JP2011122039A - Surface protective film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface protective film that has very few fish eyes, superior blocking property without use of an antiblocking agent, superior flexibility, improved controlling of exfoliation force and improved feed performance. <P>SOLUTION: This surface protective film includes an adhesive layer formed on one side surface of a substrate layer and an exfoliation processing layer formed on the other side surface of the substrate layer. The substrate layer is made of a specific MFR-having propylene-ethylene block copolymer which is produced through sequential polymerization using a metallocene catalyst which makes, at a first step, a propylene homopolymer or a propylene-ethylene random copolymer, and at a second step, a propylene-ethylene random copolymer. The adhesive layer is made of an ethylene-α-olefin copolymer as a main component which is polymerized using the metallocene catalyst, and has a specific density, a TREF value and a molecular weight distribution. The exfoliation processing layer has a central plane average roughness (SRa) on the layer surface of the exfoliation processing layer is within a range of 0.2-1.5 μm when measured under a specific condition. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a film for surface protection, and more specifically, for surface protection of building members such as synthetic resin plates, decorative plates, metal plates, and glass plates, and surface protection of liquid crystal display device components such as polarizing plates and retardation plates. The present invention relates to a film for protecting a propylene-based surface which is suitably used as an application.

Surface protection films are affixed to building materials such as synthetic resin boards, and liquid crystal display parts of optical equipment and electronic and electrical equipment from the viewpoint of scratching and soiling the surface during assembly processing, transportation, etc. It is common to peel off and use the surface protection film after assembly processing or after transportation and transportation.
Conventionally, as a surface protective film, there is a surface protective film mainly composed of an ethylene-based resin. For example, a surface protective film made of an ethylene-based resin that is polymerized from a metallocene catalyst, has a narrow composition distribution and molecular weight distribution, and does not have fisheye is described (for example, see Patent Document 1). Further, a polyethylene composed of 50 to 90% by weight of a specific low density polyethylene and 10 to 50% by weight of a specific high density polyethylene having a weight average molecular weight / number average molecular weight ratio of 9 to 15, and an ethylene-unsaturated ester A laminated film obtained by coextruding an adhesive layer made of a copolymer is described (for example, see Patent Document 2).

However, in the surface protective film described in the above-mentioned patent document, since polyethylene is the main component, stagnation occurs inside the molding machine extruder, etc. during film formation, gelation occurs due to deterioration of the ethylene component, and the film Since fish eyes are generated inside, when pasted on the object to be protected and then stacked and stored as it is, the object to be protected is dented due to the presence of the fish eyes. Therefore, for example, even if an attempt is made to use the laminated film as a polarizing plate or a retardation plate used as a liquid crystal display material, there is a problem that the image is distorted due to the dents and cannot be applied.
In addition, in view of problems of heat resistance, scratch resistance, and rigidity of polyethylene, and having improved the point defects of the metal thin film layer due to the influence of chlorine ions, it is made of polypropylene having a chlorine content of 5 ppm by weight or less. A surface protective film mainly comprising a characteristic propylene-based resin has also been proposed (see, for example, Patent Document 3). However, even in the propylene resin described in the patent document, gelation like polyethylene does not occur, but the molecular weight distribution is wide, that is, low molecular weight having a low molecular weight and high molecular weight having a high molecular weight are mixed. Therefore, when the high molecular weight component is formed into a film, an unmelted fine lump becomes fish eye and exists in the film, resulting in a dent in the object to be protected.

  Further, both ethylene-based resins and propylene-based resins have a crystallinity distribution, but there is a problem that if the crystallinity distribution is wide and there are many low crystal components, the object to be protected is contaminated. In addition, in the process of producing the polymer, sticking of the low crystal component causes polymer adhesion in a polymerization tank or the like, resulting in deterioration of the polymer due to stagnation, and as a result, fish eyes derived from polymer degradation products exist in the film. As a result, the object to be protected is dented, and there is a problem that it cannot be applied as a surface protective film. In addition, if the crystallinity distribution is wide, the compatibility between the low crystallinity component and the high crystallinity component becomes non-uniform, and the high crystallinity component becomes an unmelted fine lump and easily exists as fish eyes. Therefore, there is a problem that it cannot be applied as a surface protective film.

JP-A-9-111208 JP 54-133578 A JP 2006-282761 A

  In view of the problems of the prior art described above, the present invention has very little fish eye, excellent blocking properties without using an anti-blocking agent, excellent flexibility, peeling force control and feeding performance. Improved propylene-based film suitable for protecting the surface of building materials such as synthetic resin plates, decorative plates, metal plates, and glass plates, and for protecting the surface of liquid crystal display components such as polarizing plates and retardation plates It aims at providing the film for resin surface protection.

  As a result of repeating various studies to solve the above problems, the present inventor used a propylene-ethylene block copolymer having a specific MFR produced by a specific manufacturing method as a base material layer, and having a specific density and temperature increase. Elution fraction (TREF) measured at an elution amount of 20 ° C. or less, an ethylene / α-olefin copolymer having a ratio of the weight average molecular weight and the number average molecular weight is used for the adhesive layer, and the center plane average roughness of the release treatment layer surface By making (SRa) within the range of 0.2 to 1.5 μm, the self-adhesion made of propylene-based resin with less fish eye, excellent flexibility, and excellent peel force control and feeding performance. The present inventors have found that a surface protective film of a mold can be obtained and completed the present invention.

That is, according to the first aspect of the present invention, in the surface protection film in which the adhesive layer is formed on one surface of the base material layer and the release treatment layer is formed on the other surface, the base material layer is made of metallocene. A propylene-ethylene block copolymer (A) polymerized using a catalyst and having the following characteristics (a1) and (a2) is formed, the adhesive layer is polymerized using a metallocene catalyst, and the following (b1) to (B3) is a layer mainly composed of an ethylene / α-olefin copolymer (B) having a characteristic of (b3), which is based on the average surface roughness of the release treatment layer surface (SRa: JIS B0651 (2001)). A film for surface protection is provided, wherein the film is measured in the MD direction of the film with a needle-type surface roughness measuring instrument in the range of 0.2 to 1.5 μm.
(A) Propylene-ethylene block copolymer (a1) 30% to 95% by weight of propylene homopolymer or propylene-ethylene random copolymer component (A1) in the first step using the metallocene catalyst, the second step in propylene contains more ethylene than the component (A1) - ethylene random copolymer component (A2) to 70 to 5 wt% sequential polymerization to obtain a propylene - ethylene block copolymer (a2) a melt flow rate ( MFR: 230 ° C. 2.16 kg) is 1 to 30 g / 10 minutes (B) ethylene / α-olefin copolymer (b1) Density is 0.860 to 0.915 g / cm ³
(B2) Elevated temperature elution fractionation (TREF) measurement using orthodichlorobenzene as a solvent, elution amount of 20 ° C. or less is 60% by weight or less (b3) Ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / Mn) is 3.5 or less

Further, according to the second invention of the present invention, there is provided a surface protective film characterized in that, in the first invention, the propylene-ethylene block copolymer (A) further satisfies the following property (a3): Provided.
(A3) The component amount W having a molecular weight of 5,000 or less obtained by gel permeation chromatography (GPC) is 0.8% by weight or less of the total.

According to the third invention of the present invention, in the first or second invention, the propylene-ethylene block copolymer (A) satisfies the following characteristics (a4) to (a5): A surface protecting film is provided.
(A4) The component (A1) obtained in the first step is a propylene-ethylene random copolymer having an ethylene content of 0.5 to 6% by weight, and the proportion in the entire propylene-ethylene block copolymer is 30 to 85%. %, And the component (A2) obtained in the second step has an ethylene content of 6 to 20% by weight more than (A1), and the proportion in the total propylene-ethylene block copolymer is 70 to 15 (A5) Plot of elution amount (dWt% / dT) against temperature by temperature rising elution fractionation method (TREF) in the temperature range of −15 ° C. to + 140 ° C. using o-dichlorobenzene solvent In the TREF elution curve obtained as
The peak temperature T (A1) observed on the high temperature side is in the range of 55 to 96 ° C.,
The peak temperature T (A2) observed on the low temperature side is 45 ° C. or lower, or the peak temperature T (A2) is not observed,
The temperature T (A4) at which 99% by weight of the propylene-ethylene block copolymer elutes is 98 ° C. or lower.

According to the fourth invention of the present invention, in any one of the first to third inventions, the propylene-ethylene block copolymer (A) satisfies the following properties (a6) to (a7). A surface protective film is provided.
(A6) The component (A1) obtained in the first step is a propylene-ethylene random copolymer having an ethylene content of 1.5 to 6% by weight, and the proportion of the entire propylene-ethylene block copolymer is 30 to 70. Component (A2) in the range of wt%, obtained in the second step, has an ethylene content of 8-15 wt% more than (A1), and the proportion of propylene-ethylene block copolymer as a whole is 70- (A7) The amount of elution (dWt% / dT) with respect to the temperature by the temperature rising elution fractionation method (TREF) in the temperature range of −15 ° C. to + 140 ° C. using an o-dichlorobenzene solvent. In the TREF elution curve obtained as a plot:
The peak temperature T (A1) observed on the high temperature side is in the range of 60 to 88 ° C.,
The peak temperature T (A2) observed on the low temperature side is 40 ° C. or lower, or the peak temperature T (A2) is not observed,
The temperature T (A4) at which 99% by weight of the propylene-ethylene block copolymer elutes is 90 ° C. or lower.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the propylene-ethylene block copolymer (A) further satisfies the following property (a8): A surface protecting film is provided.
(A8) Intrinsic viscosity [η] cxs measured in a decalin at 135 ° C. for 23 ° C. xylene solubles is 1 to 2 dl / g. According to the sixth invention of the present invention, In any one of the inventions, there is provided a film for surface protection, wherein the propylene-ethylene block copolymer (A) further satisfies the following property (a9).
(A9) In the temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA), the tan δ curve has a single peak at 0 ° C. or lower.

Moreover, according to the seventh invention of the present invention, in any one of the first to sixth inventions, there is provided a surface protecting film that is used for protecting a surface of a building member.
Furthermore, according to the eighth invention of the present invention, there is provided a surface protecting film characterized in that in any one of the first to sixth inventions, the film is used for protecting a surface of a constituent member of a liquid crystal display.

The surface protective film of the present invention uses a specific propylene-ethylene block copolymer polymerized using a metallocene catalyst for the base layer and a specific ethylene / α-polymer polymerized using a metallocene catalyst for the adhesive layer. By using an olefin copolymer, when at least one of the base material layer and the adhesive layer is laminated in a molten state, it adheres firmly and has excellent delamination, so that unmelted fish eyes are very There is little fear of delamination between the adhesive layer and the base material layer, it is rich in flexibility, and exhibits excellent adhesiveness. For this reason, even if the film for surface protection is affixed to an object to be protected and stacked and stored, the object to be protected does not dent.
Moreover, the film for surface protection of this invention is excellent in blocking property without using an antiblocking agent, and is excellent in a softness | flexibility. Furthermore, by making the center plane average roughness (SRa) of the surface of the release treatment layer in the range of 0.2 to 1.5 μm, from the roll winding state where both the adhesive layer and the release treatment layer are in contact with each other in a solid state, When the roll is unwound, it can be peeled off smoothly, and when used, it can be made into a film for surface protection having the property of improving the pay-out property.

It is a figure which shows the elution amount and elution amount integration | accumulation of the components (A1) and (A2) by TREF.

The present invention is a propylene-based surface protective film having an adhesive layer formed on one surface of a base material layer and having a release treatment layer on the opposite surface of the adhesive layer, and the base material layer is polymerized using a metallocene catalyst. And the characteristics (a1) and (a2), and if necessary, further formed with a propylene-ethylene block copolymer (A) having the characteristics (a3) to (a9), and the adhesive layer using a metallocene catalyst Polymerized and formed of a propylene / α-olefin random copolymer (B) having characteristics (b1) to (b3), and the release treatment layer has a center plane average roughness (SRa) of 0.2 to 0.2 on the release treatment layer surface. It is a film for surface protection characterized by being in the range of 1.5 micrometers.
Hereinafter, the component of each layer of the film for surface protection of this invention and the manufacturing method of the film for surface protection are demonstrated in detail.

1. Base material layer The following propylene-ethylene block copolymer (A) is used for the base material layer and the adhesive layer in the film for surface protection of the present invention.
The propylene-ethylene block copolymer (A) used in the present invention is a propylene homopolymer or a propylene-ethylene random copolymer component (A1) (hereinafter sometimes referred to as component (A1)) and propylene-. It is composed of an ethylene random copolymer component (A2) (hereinafter sometimes referred to as component (A2)), and the following properties (a1) to (a2), and further, if necessary, properties (a3) to (a9) It satisfies.

(A1) Using a metallocene-based catalyst, 30 to 95% by weight of propylene homopolymer or propylene-ethylene random copolymer component (A1) in the first step and more ethylene than component (A1) in the second step A propylene-ethylene block copolymer obtained by sequentially polymerizing 70 to 5% by weight of a propylene-ethylene random copolymer component (A2) containing a propylene-ethylene block copolymer (A), Although it is commonly called a block copolymer, it is in a blended state of the component (A1) and the component (A2), and both are not polymerized and bonded.
(A2) Melt flow rate (MFR: 230 ° C. 2.16 kg) is 1 to 30 g / 10 min

(A3) The component amount W (Mw ≦ 5,000) having a molecular weight of 5,000 or less obtained by gel permeation chromatography (GPC) measurement is 0.8% by weight or less of the total (a4) obtained in the first step. Component (A1) is a propylene-ethylene random copolymer having an ethylene content of 0.5 to 6% by weight, and its proportion in the entire propylene-ethylene block copolymer is in the range of 30 to 85% by weight. The component (A2) obtained in (6) has an ethylene content of 6 to 20% by weight more than (A1), and the proportion in the entire propylene-ethylene block copolymer is in the range of 70 to 15% by weight (a5). Elution amount (dWt% / dT) with respect to temperature by temperature rising elution fractionation method (TREF) in a temperature range of −15 ° C. to + 140 ° C. using o-dichlorobenzene solvent In TREF elution curve obtained as a lot,
The peak temperature T (A1) observed on the high temperature side is in the range of 55 to 96 ° C.,
The peak temperature T (A2) observed on the low temperature side is 45 ° C. or lower, or the peak temperature T (A2) is not observed,
The temperature T (A4) at which 99% by weight of the propylene-ethylene block copolymer elutes is 98 ° C. or lower.

(A6) The component (A1) obtained in the first step is a propylene-ethylene random copolymer having an ethylene content of 1.5 to 6% by weight, and the proportion of the entire propylene-ethylene block copolymer is 30 to 70. The component (A2) in the range of wt% and obtained in the second step has an ethylene content of 8 to 15 wt% more than (A1), and the proportion in the total propylene-ethylene block copolymer is 70 to In the range of 30% by weight

(A7) TREF elution curve obtained as a plot of elution amount (dWt% / dT) against temperature by the temperature rising elution fractionation method (TREF) in the temperature range of −15 ° C. to + 140 ° C. using an o-dichlorobenzene solvent In
The peak temperature T (A1) observed on the high temperature side is in the range of 60 to 88 ° C.,
The peak temperature T (A2) observed on the low temperature side is 40 ° C. or lower, or the peak temperature T (A2) is not observed,
The temperature T (A4) at which 99% by weight of the propylene-ethylene block copolymer elutes is 90 ° C. or lower. (A8) The intrinsic viscosity [η] cxs of 23 ° C. xylene solubles measured in 135 ° C. decalin is 1 to 2 dl / g (a9) In the temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA), the tan δ curve has a single peak at 0 ° C. or less. (A9) will be described in detail.

(1) Ethylene content in component (A1) ([E] _A1 )
The component (A1) produced in the first step is a propylene homopolymer having a relatively high melting point and crystallinity, or propylene-ethylene random copolymer, in order to suppress stickiness of the film and develop heat resistance. Must be coalesced. Ethylene content of component _{(A1) ([E] A1} ) is preferably at 7 wt% or less, more preferably 6 wt% or less, more preferably from 0.5 to 6 wt. [E] If _A1 exceeds 7% by weight, the melting point becomes too low, which may deteriorate the heat resistance of the film.
In addition, although component (A1) shows the adhesiveness and heat resistance which were improved also with the propylene homopolymer, in order to exhibit sufficient adhesiveness when component (A1) is a propylene homopolymer, the component (described later) There is a concern that the ratio of A2) needs to be extremely increased, which may cause remarkable deterioration such as heat resistance, stickiness and blocking.
On the other hand, when component (A1) is a propylene-ethylene random copolymer, although the melting point of component (A1) itself decreases, the heat resistance seems to deteriorate, but it is necessary to exhibit sufficient adhesiveness. Since the amount of the component (A2) can be suppressed, the heat resistance of the block copolymer as a whole is rather improved, and the deterioration of stickiness and blocking is small, which is preferable.
Furthermore, since the melting point can be lowered, sufficient extrusion stability and the like can be obtained even if the molding temperature at the time of film molding is lowered, so that a film with extremely excellent odor can be obtained.
From these viewpoints, the ethylene content [E] _A1 in the component (A1) is preferably 0.5% by weight or more, more preferably 1.5% by weight or more.

(2) Ethylene content in component (A2) ([E] _A2 )
The propylene-ethylene random copolymer component (A2) produced in the second step is a component necessary for improving the tackiness, impact resistance and flexibility of the propylene-ethylene block copolymer (A). .
Here, the component (A2) needs to have a specific ethylene content in order to sufficiently exhibit the above effects. That is, in the block copolymer (A) of the present invention, the lower the crystallinity of the component (A2) relative to the component (A1), the greater the effect of improving the tackiness, and the crystallinity is in the propylene-ethylene random copolymer. Therefore, the ethylene content [E] _A2 in the component (A2) needs to be larger than the ethylene content [E] _A1 E in the component (A1), preferably 3% by weight. As mentioned above, More preferably, it is 6 weight% or more, More preferably, it is 8 weight% or more, and contains more ethylene than a component (A1).
Here, when the difference in ethylene content between the component (A1) and the component (A2) is defined as [E] gap ([E] _A2− [E] _A1 ), [E] gap is in the range of 3 to 20% by weight. More preferably, it is 6-20 weight%, More preferably, it is 8-15 weight%.
[E] When the gap is less than 3% by weight, the rubber elasticity is insufficient, which is not preferable. On the other hand, if it exceeds 20% by weight, a phase separation structure divided into a matrix and a domain of the component (A1) and the component (A2) produced in the first step is taken and compatibility is deteriorated, so that fish eyes may be generated. There is. This is because polypropylene originally has low compatibility with polyethylene, and even in propylene-ethylene random copolymers, although the ethylene content is different, the mutual compatibility decreases as the difference in ethylene content increases. is there.

(3) Ratio of component (A1) and component (A2) Ratio of component (A1) constituting propylene-ethylene block copolymer (W (A1)) and ratio of component (A2) (W (A2)) The content ratio is such that W (A1) is in the range of 30 to 95% by weight and W (A2) is in the range of 70 to 5% by weight. %, More preferably in the range of 30 to 70% by weight.
If the ratio of W (A1) is less than 30% by weight, stickiness of the film may occur and heat resistance may be reduced. On the other hand, when the ratio of W (A1) exceeds 95% by weight, the effect of improving the tackiness and impact resistance of the propylene-ethylene block copolymer cannot be sufficiently exhibited.
When the proportion of the component (A2) is too large, the stickiness increases, the blocking is deteriorated, and the heat resistance is significantly lowered. On the other hand, if the proportion of the component (A2) is too small, the effect of improving flexibility and impact resistance cannot be obtained.

(4) Measurement of _{[E] A1} and _{[E] A2} and W (A1) and was measured above W (A2) _{[E] A1} and _{[E] A2} and W (A1) and W (A2) is prepared Although it is possible to specify by the material balance of the time (material balance), in order to specify these more accurately, it is desirable to use the following analysis.
(I) Identification of W (A1) and W (A2) by temperature-temperature elution fractionation (TREF) The technique for evaluating the crystallinity distribution of a propylene-ethylene random copolymer by TREF is well known to those skilled in the art. Yes, for example, detailed measurement methods are shown in the following documents.
G. Glockner, J. et al. Appl. Polym. Sci. : Appl. Polym. Symp. 45, 1-24 (1990)
L. Wild, Adv. Polym. Sci. 98, 1-47 (1990)
J. et al. B. P. Soares, A .; E. Hamielec, Polymer; 36, 8, 1639-1654 (1995)

  The propylene-ethylene block copolymer in the present invention is greatly different in the crystallinity of each of the components (A1) and (A2), and each crystallinity distribution is narrow by being produced using a metallocene catalyst. Therefore, there are very few intermediate components between the two, and both can be discriminated with high accuracy by TREF.

A specific method will be described with reference to the figure showing the elution amount and the elution amount integration by TREF in FIG.
FIG. 1 is a graph of a TREF elution curve of a propylene-ethylene block copolymer (PEB-1) for a base material layer of the present invention produced in Example (Production Example 1). The plot line in the upper diagram of FIG. 1 shows the amount of elution at each temperature, and the plot line in the lower diagram shows the integration of the elution amount.
In the TREF elution curve (plot of elution amount with respect to temperature), component (A1) and component (A2) show their elution peaks at T (A1) and T (A2), respectively, due to the difference in crystallinity. Since it is sufficiently large, separation is possible at an intermediate temperature T (C) (= {T (A1) + T (A2)} / 2).
In addition, the lower limit of the TREF measurement temperature is −15 ° C. in the apparatus used for this measurement, but in the case where the crystallinity of the component (A2) is very low or an amorphous component, There may be no peak in the range. (In this case, the concentration of the component (A2) dissolved in the solvent at the measurement temperature lower limit (that is, −15 ° C.) is detected.)
At this time, T (A2) is considered to exist below the lower limit of the measurement temperature, but the value cannot be measured. In such a case, T (A2) is the lower limit of the measurement temperature. Defined as ° C.
Here, if the integrated amount of the component eluted by T (C) is defined as W (A2) wt%, and the integrated amount of the component eluted at T (C) or higher is defined as W (A1) wt%, W (A2) Almost corresponds to the amount of the component (A2) having low crystallinity or non-crystallinity, and the integrated amount W (A1) of the component eluted at T (C) or higher is the component (A1) having relatively high crystallinity. Almost corresponds to the amount of. The elution amount curve obtained by TREF and the above-described methods for calculating the various temperatures and amounts obtained therefrom are performed as illustrated in FIG.

(Ii) TREF measurement method In the present invention, TREF is specifically measured as follows.
A sample is dissolved in o-dichlorobenzene (containing 0.5 mg / mL BHT) at 140 ° C. to obtain a solution. This is introduced into a 140 ° C. TREF column, cooled to 100 ° C. at a rate of 8 ° C./min, subsequently cooled to −15 ° C. at a rate of 4 ° C./min, and held for 60 minutes. Thereafter, o-dichlorobenzene (containing 0.5 mg / mL BHT) as a solvent is flowed through the column at a flow rate of 1 mL / min, and components dissolved in o-dichlorobenzene at −15 ° C. are eluted in the TREF column for 10 minutes. Next, the column is linearly heated to 140 ° C. at a heating rate of 100 ° C./hour to obtain an elution curve.

(Iii) Specificity of ethylene content [E] _A1 and [E] _A2 in each component (a) Separation of component (A1) and component (A2) Based on T (C) determined by the above TREF measurement, Using a temperature-separating column separation method using a preparative type separation apparatus, the soluble component (A2) in T (C) and the insoluble component (A1) in T (C) are separated, and the ethylene content of each component is determined by NMR. .
The temperature rising column fractionation method refers to a measurement method disclosed in, for example, Macromolecules, 21 314 to 319 (1988). Specifically, the following method is used in the present invention.
(B) Fractionation conditions A cylindrical column having a diameter of 50 mm and a height of 500 mm is filled with a glass bead carrier (80 to 100 mesh) and maintained at 140 ° C. Next, 200 mL of the o-dichlorobenzene solution (10 mg / mL) of the sample dissolved at 140 ° C. is introduced into the column. Thereafter, the temperature of the column is cooled to 0 ° C. at a rate of temperature decrease of 10 ° C./hour. After holding at 0 ° C. for 1 hour, the column temperature is heated to T (C) at a heating rate of 10 ° C./hour and held for 1 hour. Note that the temperature control accuracy of the column through a series of operations is ± 1 ° C.
Next, while maintaining the column temperature at T (C), 800 mL of o (dichlorobenzene) of T (C) is allowed to flow at a flow rate of 20 mL / min, whereby components soluble in T (C) existing in the column are obtained. Elute and collect.
Next, the column temperature is increased to 140 ° C. at a temperature rising rate of 10 ° C./min, and after leaving still at 140 ° C. for 1 hour, by flowing 800 mL of a 140 ° C. solvent (o-dichlorobenzene) at a flow rate of 20 mL / min, Elute insoluble components with T (C) and collect.
The solution containing the polymer obtained by fractionation is concentrated to 20 mL using an evaporator and then precipitated in 5 times the amount of methanol. The precipitated polymer is recovered by filtration and then dried overnight in a vacuum dryer.

^(C) 13 C-NMR according to the measurement the fractionated by components obtained ethylene content ^{(A1) (A2) 13 C} -NMR spectrum ethylene content was determined according to the following conditions by complete proton decoupling method for each It is obtained by analyzing.
Model: GSX-400 manufactured by JEOL Ltd. or equivalent equipment (carbon nuclear resonance frequency of 100 MHz or more)
Solvent: o-dichlorobenzene / heavy benzene = 4/1 (volume ratio)
Concentration: 100 mg / mL
Temperature: 130 ° C
Pulse angle: 90 °
Pulse interval: 15 seconds Integration count: 5,000 times or more The attribution of the spectrum may be performed with reference to Macromolecules, 17 1950 (1984), for example.
The spectrum assignments measured under the above conditions are as shown in Table 1 below. In Table 1, symbols such as S _αα represent Carman et al. (Macromolecules, 10536 (1977)), P represents a methyl carbon, S represents a methylene carbon, and T represents a methine carbon.

Hereinafter, when “P” is a propylene unit in a copolymer chain and “E” is an ethylene unit, six kinds of triads of PPP, PPE, EPE, PEP, PEE, and EEE may exist in the chain. As described in Macromolecules, 15 1150 (1982), the concentration of these triads and the peak intensity of the spectrum are linked by the following relational expressions (1) to (6).
[PPP] = k × I (T _ββ ) (1)
[PPE] = k × I (T _βδ ) (2)
[EPE] = k × I (T _δδ ) (3)
[PEP] = k × I (S _ββ ) (4)
[PEE] = k × I (S _βδ ) (5)
[EEE] = k × {I (S _δδ ) / 2 + I (S _γδ ) / 4} (6)
Here, [] indicates the fraction of triads, for example, [PPP] is the fraction of PPP triads in all triads. Therefore,
[PPP] + [PPE] + [EPE] + [PEP] + [PEE] + [EEE] = 1 (7)
It is.
Further, k is a constant, I indicates spectral intensity, and for example, I (T _ββ ) means the intensity of a peak at 28.7 ppm attributed to T _ββ .

By using the relational expressions of the above formulas (1) to (7), the fraction of each triad is obtained, and further the ethylene content is obtained by the following formula.
Ethylene content (mol%) = ([PEP] + [PEE] + [EEE]) × 100

  The propylene-ethylene random copolymer of the present invention contains a small amount of a propylene hetero bond (2,1-bond and / or 1,3-bond), thereby producing the following minute peak.

In order to obtain an accurate ethylene content, it is necessary to include these peaks derived from heterogeneous bonds in the calculation, but it is difficult to completely separate and identify the peaks derived from heterogeneous bonds, and the amount of heterogeneous bonds is small. Therefore, the ethylene content of the present invention is obtained by using the relational expressions (1) to (7) in the same manner as the analysis of the copolymer produced with a Ziegler catalyst that does not substantially contain a heterogeneous bond. To do.
Conversion from mol% to wt% of ethylene content is performed using the following formula.
Ethylene content (% by weight) = (28 × X / 100) / {28 × X / 100 + 42 × (1−X / 100)} × 100
Here, X is the ethylene content in mol%.

The ethylene content [E] _W of the entire propylene-ethylene block copolymer is calculated from the respective ethylene contents [E] _A1 , [E] _A2 and TREF of the component (A1) and the component (A2) measured as described above. The weight ratio W (A1) and W (A2)% by weight of each component is calculated by the following formula.
[E] _W = {[E] _A1 × W (A1) + [E] _A2 × W (A2) / 100 (% by weight)

(4) Melt flow rate (MFR) of propylene-ethylene block copolymer (A)
The melt flow rate (MFR) of the propylene-ethylene block copolymer used in the present invention is 1 to 30 g / 10 minutes, preferably 4 to 15 g / 10 minutes. When the MFR is less than 1 g / 10 minutes, surface roughness called shark skin or melt fracture occurs on the surface of the film and the appearance is remarkably impaired. On the other hand, if the MFR is too high, the stability during molding deteriorates, the width and thickness of the film fluctuate, and a product cannot be obtained.
Here, MFR is a value measured at a heating temperature of 230 ° C. and a load of 2.16 kg (21.18 N) in accordance with JIS K7210 A method condition M.

(5) Definition by peak of tan δ curve In the present invention, in order to maintain good compatibility of the film, the component (A1) and the component (A2) constituting the propylene-ethylene block copolymer to be used are phase separated. Preferably not. The phase separation conditions are affected not only by the ethylene content but also by the molecular weight and composition. Therefore, in addition to the above-mentioned regulations concerning the ethylene content, a temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA) Therefore, it is necessary to define the peak of the tan δ curve.
In the propylene-ethylene block copolymer (A) used in the present invention, in the temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA), the tan δ curve has a single peak at 0 ° C. or lower. It is preferable to have.
When the propylene-ethylene block copolymer (A) has a phase separation structure, the glass transition temperature of the amorphous part contained in the component (A1) and the glass transition temperature of the amorphous part contained in the component (A2) are Since each is different, there are a plurality of peaks. In this case, there arises a problem that fish eyes are likely to occur.
Whether or not the phase separation structure is taken can be determined in the tan δ curve in the solid viscoelasticity measurement, and the tan δ curve has a single peak below 0 ° C. Is brought about by

  Specifically, solid viscoelasticity measurement is performed by applying a sinusoidal strain of a specific frequency to a strip-shaped sample piece and detecting the generated stress. Here, the frequency is 1 Hz and the measurement temperature is raised stepwise from −60 ° C. until the sample is melted and cannot be measured. Further, it is recommended that the magnitude of distortion is about 0.1 to 0.5%. From the obtained stress, the storage elastic modulus G ′ and the loss elastic modulus G ″ are obtained by a known method, and the loss tangent (= loss elastic modulus / storage elastic modulus) defined by this ratio is plotted against the temperature. It shows a sharp peak in the temperature range below 0 ° C. Generally, the peak of the tan δ curve below 0 ° C. is for observing the glass transition of the amorphous part, and here the peak temperature is defined as the glass transition temperature Tg (° C.). Define.

(6) Molecular weight The amount of the component having a weight average molecular weight of 5,000 or less measured by gel permeation (GPC) method of the propylene-ethylene block copolymer (A) used in the present invention is 0.8% by weight. The following is preferable, and more preferably 0.5% by weight or less. The propylene-ethylene block copolymer (A) in the present invention has an additional feature that the low molecular weight component is small, and the low molecular weight component, particularly the component whose molecular weight is less than the entangled molecular weight, It is thought that the surface bleeds out and the stickiness and contamination resistance to the adherend are deteriorated.
In addition, the molecular weight between the entanglement points of polypropylene is about 5,000 as described in Journal of Polymer Science: Part B: Polymer Physics; 37 1023-1103 (1999).

Here, the weight average molecular weight (Mw) refers to that measured by gel permeation chromatography (GPC).
Conversion from the retention volume to the molecular weight is performed using a calibration curve prepared in advance with standard polystyrene.
Standard polystyrenes used are the following brands manufactured by Tosoh Corporation.
F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000
A calibration curve is prepared by injecting 0.2 ml of a solution dissolved in o-dichlorobenzene (containing 0.5 mg / ml BHT) so that each is 0.5 mg / ml.
The calibration curve uses a cubic equation obtained by approximation by the least square method. Viscosity formula used for conversion to molecular weight:
[Η] = K × M ^α uses the following numerical values.
PS: K = 1.38 × 10 ⁻⁴ α = 0.7
PE: K = 3.92 × 10 ⁻⁴ α = 0.733
PP: K = 1.03 × 10 ⁻⁴ α = 0.78

The measurement conditions for GPC are as follows.
Apparatus: GPC (ALC / GPC 150C) manufactured by WATERS
Detector: MIRAN 1A IR detector manufactured by FOXBORO (measurement wavelength: 3.42 μm)
Column: AD806M / S (3 pieces) manufactured by Showa Denko KK
Mobile phase solvent: o-dichlorobenzene Measurement temperature: 140 ° C.
Flow rate: 1.0 ml / min
Injection volume: 0.2ml
Sample Preparation Prepare a 1 mg / ml solution using o-dichlorobenzene (containing 0.5 mg / ml BHT) and dissolve it at 140 ° C. for about 1 hour.
From the plot of the elution ratio against the molecular weight obtained by GPC measurement, the amount of components having a molecular weight of 5,000 or less can also be determined.

(7) Intrinsic viscosity [η] cxs
In the propylene-ethylene block copolymer (A), it is a component (CXS component) that is soluble in xylene at room temperature, in which stickiness and bleed out are particularly problematic. Therefore, the measurement of intrinsic viscosity [η] cxs is: It is preferable to carry out for the CXS component.
Here, the CXS component was prepared by dissolving the propylene-ethylene block copolymer (A) in p-xylene at 130 ° C. to form a solution, and then leaving the solution at 25 ° C. for 12 hours. The intrinsic viscosity [η] cxs of the obtained CXS component obtained by evaporating p-xylene can be measured using a Ubbelohde viscometer at a temperature of 135 ° C. using decalin as a solvent.
At this time, since the propylene-ethylene block copolymer (A) of the present invention does not increase the generation of a component having a molecular weight of 5,000 or less that tends to bleed out, the conventional Ziegler-Natta catalyst is Even if the intrinsic viscosity [η] cxs of the CXS component is in the region of 2 or less, which has been a practical problem due to deterioration of the above problems or blocking, it can be produced and used without causing any particular deterioration of physical properties. it can.
The propylene-ethylene block copolymer which does not increase the component having a molecular weight of 5,000 or less while lowering the intrinsic viscosity of such a CXS component has characteristics in terms of physical properties such as high tensile elongation at break and high tensile strength at break. In addition, there is an effect that appearance defects called “butsu” and “fish eyes” are less likely to occur.

(8) Additional requirement of crystallinity distribution by TREF elution curve By using the TREF elution curve used for specifying the amount of each component, the propylene-ethylene block copolymer (A) used in the present invention has crystals. Additional features can be found in the sex distribution.
(I) Elution peak temperature T (A1)
The higher the elution peak temperature T (A1) of the component (A1) in the TREF elution curve, the higher the crystallinity of the component (A1). At this time, when the crystallinity of the component (A1) increases, the propylene-ethylene block In order to improve the adhesiveness of the polymer (A), the component (A2) must be increased.
On the other hand, if the proportion of the component (A2) is too large, stickiness and heat resistance are deteriorated. Therefore, in order to improve the balance between adhesiveness and flexibility, T (A1) should not be too high. Furthermore, although odor etc. have a tendency to get worse as the molding temperature increases, it is preferable that T (A1) is reduced from the viewpoint that stable plasticization can be obtained even if the extrusion temperature during molding is lowered.
In the present invention, the component (A1) is a propylene homopolymer or a propylene-ethylene random copolymer, but T (A1) can be lowered by increasing the ethylene content. At this time, T (A1) is preferably 96 ° C. or lower, and the most preferable range is 88 ° C. or lower in order to exhibit a sufficient balance of adhesiveness, flexibility and heat resistance.
On the other hand, when the elution peak temperature T (A1) is less than 55 ° C., the temperature at which the component (A1) crystals melt is low, and the propylene-ethylene block copolymer can exhibit sufficient heat resistance. Therefore, in the present invention, the peak temperature T (A1) is preferably 55 ° C. or higher, and more preferably 60 ° C. or higher.

(Ii) Elution end temperature T (A4)
Even if the peak temperature T (A1) is low, the fish eye is deteriorated if the crystallinity distribution is present on the high crystal side. The reason for this is not clear, but if there is a crystalline distribution on the high crystal side, the density of the crystal structure increases and the density difference from the amorphous part increases, or the nucleation frequency decreases and the spherulite size increases. It is inferred to do.
Therefore, it is preferable that the spread of crystallinity toward the high temperature side is suppressed in the TREF elution curve. The spread of crystallinity to the high crystal side can be evaluated by TREF measurement, and the elution end temperature T (A4) of the entire component propylene-ethylene block copolymer (A) with respect to the peak temperature T (A1) (provided that Considering errors in TREF measurement, it is difficult to define the temperature at which all elution is performed. Therefore, in the present invention, the temperature at which 99% by weight of the total is eluted is defined as the elution end temperature T (A4)). Preferably, there is an elution component on the high temperature side, and the crystallinity of the component increases. Therefore, as a preferable requirement of the present invention, T (A4) is 98 ° C. or less, preferably 90 ° C. or less.
Furthermore, the temperature difference ΔT (T (A4) −T (A1)) from the elution peak to the end of elution is preferably 5 ° C. or less, more preferably 4 ° C. or less, and even more preferably 3 ° C. or less. .

(Iii) Elution peak temperature T (A2)
If the crystallinity of the component (A2) is not sufficiently lowered, the tackiness and flexibility of the propylene-ethylene block copolymer (A) cannot be ensured. Therefore, T (A2) is preferably 45 ° C. or lower. More preferably, it is 40 ° C. or lower.

(9) Production of propylene-ethylene block copolymer (A) The method for producing the propylene-ethylene block copolymer (A) of the present invention requires the use of a metallocene catalyst. It is well known to those skilled in the art that stickiness and bleedout deteriorate when the molecular weight and crystallinity distribution are wide in the propylene-ethylene block copolymer, but also in the propylene-ethylene block copolymer used in the present invention, In order to suppress stickiness and bleed out, and to achieve less fisheye in film formation, it is necessary to polymerize using a metallocene catalyst that can narrow the molecular weight and crystallinity distribution, It is clear from the comparison of Examples and Comparative Examples described later that the Ziegler-Natta catalyst cannot provide the excellent propylene-ethylene block copolymer of the present invention.

Here, the type of the metallocene-based catalyst is not particularly limited as long as a copolymer having the performance of the present invention can be produced, but in order to satisfy the requirements of the present invention, for example, as shown below: It is preferable to use a metallocene-based catalyst comprising the component (x), the component (y), and the component (z) used as necessary.
Component (x): At least one metallocene transition metal compound selected from the transition metal compounds represented by the general formula (1) Component (y): At least one selected from the following (y-1) to (y-4) Ionic compound capable of reacting with solid component (y-1), particulate carrier (y-2) component (x) on which solid organic component (y-1) is supported, and converting component (x) into a cation Fine carrier on which Lewis acid is supported (y-3) Solid acid fine particle (y-4) Ion exchange layered silicate component (z): Organoaluminum compound

Ingredient (x)
As the component (x), at least one metallocene transition metal compound selected from transition metal compounds represented by the following general formula (1) can be used.
^{_{Q (C 5 H 4-a}} -aR 1) (C 5 H 4-b -bR 2) MeXY ... (1)
[Wherein Q represents a divalent linking group that bridges two conjugated five-membered ring ligands, Me represents a metal atom selected from titanium, zirconium, and hafnium, and X and Y represent hydrogen atoms. Atom, halogen atom, hydrocarbon group, alkoxy group, amino group, nitrogen-containing hydrocarbon group, phosphorus-containing hydrocarbon group or silicon-containing hydrocarbon group, X and Y are each independently, ie, the same or different. Also good. R ¹ and R ² represent hydrogen, hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group or phosphorus-containing hydrocarbon group. . a and b are the number of substituents. ]

Specifically, Q represents a divalent linking group that bridges two conjugated five-membered ring ligands. For example, a divalent hydrocarbon group, a silylene group, an oligosilylene group, or a hydrocarbon group as a substituent. Examples thereof include a silylene group, an oligosilylene group, or a germylene group having a hydrocarbon group as a substituent. Among these, preferred are a divalent hydrocarbon group and a silylene group having a hydrocarbon group as a substituent.
X and Y each represents a hydrogen atom, a halogen atom, a hydrocarbon group, an alkoxy group, an amino group, a nitrogen-containing hydrocarbon group, a phosphorus-containing hydrocarbon group, or a silicon-containing hydrocarbon group. And chlorine, methyl, isobutyl, phenyl, dimethylamide, diethylamide group and the like. X and Y may be independent, that is, may be the same or different.

R ¹ and R ² represent hydrogen, a hydrocarbon group, a halogenated hydrocarbon group, a silicon-containing hydrocarbon group, a nitrogen-containing hydrocarbon group, an oxygen-containing hydrocarbon group, a boron-containing hydrocarbon group, or a phosphorus-containing hydrocarbon group. .
Specific examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a phenyl group, a naphthyl group, a butenyl group, and a butadienyl group. In addition, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group or phosphorus-containing hydrocarbon group include methoxy group, ethoxy group, phenoxy group, trimethylsilyl group. Typical examples include a group, a diethylamino group, a diphenylamino group, a pyrazolyl group, an indolyl group, a dimethylphosphino group, a diphenylphosphino group, a diphenylboron group, and a dimethoxyboron group. Among these, a hydrocarbon group having 1 to 20 carbon atoms is preferable, and a methyl group, an ethyl group, a propyl group, and a butyl group are particularly preferable.
By the way, adjacent R ¹ and R ² may combine to form a ring, on which a hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing You may have a substituent which consists of a hydrocarbon group, a boron containing hydrocarbon group, or a phosphorus containing hydrocarbon group.
Me is a metal atom selected from titanium, zirconium and hafnium, preferably zirconium or hafnium.

  Among the components (x) described above, those preferable for production of the propylene-ethylene block copolymer (A) used in the present invention are crosslinked with a silylene group, a germylene group or an alkylene group having a hydrocarbon substituent. A transition metal compound comprising a ligand having a substituted cyclopentadienyl group, a substituted indenyl group, a substituted fluorenyl group, or a substituted azulenyl group, particularly preferably a silylene group having a hydrocarbon substituent or a germylene group. It is a transition metal compound comprising a ligand having a bridged 2,4-position substituted indenyl group and 2,4-position substituted azulenyl group.

Non-limiting examples include
Dimethylsilylene bis (2-methyl-4-phenylindenyl) zirconium dichloride,
Diphenylsilylenebis (2-methyl-4-phenylindenyl) zirconium dichloride,
Dimethylsilylenebis (2-methylbenzoindenyl) zirconium dichloride,
Dimethylsilylenebis {2-isopropyl-4- (3,5-diisopropylphenyl) indenyl} zirconium dichloride,
Dimethylsilylene bis (2-propyl-4-phenanthrylindenyl) zirconium dichloride, dimethylsilylene bis (2-methyl-4-phenylazurenyl) zirconium dichloride,
Dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) azurenyl} zirconium dichloride,
Dimethylsilylenebis (2-ethyl-4-phenylazurenyl) zirconium dichloride,
Dimethylsilylenebis (2-isopropyl-4-phenylazurenyl) zirconium dichloride,
Dimethylsilylenebis {2-ethyl-4- (2-fluorobiphenyl) azurenyl} zirconium dichloride,
Examples include dimethylsilylene bis {2-ethyl-4- (4-t-butyl-3-chlorophenyl) azurenyl} zirconium dichloride.
A compound in which the silylene group of these specific examples is replaced with a germylene group and zirconium is replaced with hafnium is also exemplified as a suitable compound. In addition, since the catalyst component is not an important element of the present invention, it avoids complicated listing and is limited to a representative example, but it is obvious that the effective range of the present invention is not limited thereby. It is.

Ingredient (y)
As the component (y), at least one solid component selected from the components (y-1) to (y-4) described above is used. Each of these components is known and can be used by appropriately selecting from known techniques. Specific examples and manufacturing methods thereof are described in detail in JP-A No. 2002-284808, JP-A No. 2002-53609, JP-A No. 2002-69116, JP-A No. 2003-105015, and the like.
Here, as the particulate carrier used for the component (y-1) and the component (y-2), inorganic oxides such as silica, alumina, magnesia, silica alumina, silica magnesia, magnesium chloride, magnesium oxychloride, chloride Examples thereof include inorganic halides such as aluminum and lanthanum chloride, and porous organic carriers such as polypropylene, polyethylene, polystyrene, styrene divinyl benzene copolymer, and acrylic acid copolymer.

Further, as a non-limiting specific example of the component (y), a particulate carrier on which methylalumoxane, isobutylalumoxane, methylisobutylalumoxane, aluminum butylboronate tetraisobutyl, etc. are supported as the component (y-1). As component (y-2), triphenylborane, tris (3,5-difluorophenyl) borane, tris (pentafluorophenyl) borane, triphenylcarbonium tetrakis (pentafluorophenyl) borate, N, N-dimethyl Particulate carrier carrying anilinium tetrakis (pentafluorophenyl) borate, etc. as component (y-3), alumina, silica alumina, magnesium chloride, etc. as component (y-4), montmorillonite, zakonite, beidellite , Nontronic , Saponite, hectorite, stevensite, bentonite, smectite group such as taeniolite, vermiculite, and the like mica group. These may form a mixed layer.
Particularly preferred among the above components (y) is the ion-exchange layered silicate of component (y-4), and more preferred are chemical treatments such as acid treatment, alkali treatment, salt treatment, and organic matter treatment. It is an ion exchange layered silicate applied.

Ingredient (z)
Examples of organoaluminum compounds used as the component (z) as necessary include the following general formula AlR _a X _3-a
(Wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is hydrogen, halogen, alkoxy group, and a is a number of 0 <a ≦ 3)
Or a trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum or triisobutylaluminum, or a halogen or alkoxy-containing alkylaluminum such as diethylaluminum monochloride or diethylaluminum monomethoxide. In addition, aluminoxanes such as methylaluminoxane can also be used.
Of these, trialkylaluminum is particularly preferable.

The catalyst is formed by bringing the component (x), the component (y), and the component (z) into contact with each other as necessary. The contact method is not particularly limited, but the contact can be made in the following order. Moreover, this contact may be performed not only at the time of catalyst preparation but also at the time of prepolymerization with olefin or at the time of polymerization of olefin.
(I) Component (x) is contacted with component (y) (ii) Component (x) is contacted with component (y), and then component (z) is added (iii) Component (x) and component (z) ) Is added and then component (y) is added. (Iv) Component (y) and component (z) are contacted and then component (x) is added. (V) The three components are contacted simultaneously.

The amount of components (x), (y) and (z) used in the present invention is arbitrary. For example, the amount of component (x) used relative to component (y) is preferably in the range of 0.1 to 1,000 μmol, particularly preferably 0.5 to 500 μmol, relative to 1 g of component (y). The amount of component (z) used relative to component (y) is preferably such that the amount of transition metal is 0.001 to 100 μmol, particularly preferably 0.005 to 50 μmol, relative to 1 g of component (z). Therefore, the amount of the component (z) to the component (x) is preferably in the range of 10 ⁻⁵ to 50, particularly preferably 10 ^{−4 to} 5 in terms of the molar ratio of the transition metal.

The catalyst of the present invention is preferably subjected to a prepolymerization treatment comprising contacting an olefin in advance and polymerizing a small amount. The olefin used for the prepolymerization is not particularly limited, but ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinylcycloalkane, Styrene and the like can be used, and it is particularly preferable to use propylene.
The olefin can be supplied by any method such as a supply method for maintaining the olefin at a constant speed or in a constant pressure state, a combination thereof, or a stepwise change. The prepolymerization temperature and the time thereof are not particularly limited, but are preferably in the range of −20 ° C. to 100 ° C. and 5 minutes to 24 hours, respectively. The amount of prepolymerization is such that the amount of prepolymerization polymer is 0.01 to 100, more preferably 0.1 to 50, based on the component (y) in terms of weight ratio. After completion of the prepolymerization, the catalyst can be used as it is depending on the usage form of the catalyst, but may be dried if necessary.
Furthermore, a polymer such as polyethylene, polypropylene, or polystyrene, or an inorganic oxide solid such as silica or titania can be allowed to coexist during or after the contact of the above components.

In order to produce the propylene-ethylene block copolymer (A) used in the present invention, a crystalline propylene homopolymer or a crystalline propylene-ethylene random copolymer component (A1) and a low crystalline or amorphous material are used. It is necessary to sequentially polymerize the propylene-ethylene random copolymer component (A2).
When the propylene-ethylene block copolymer is a random copolymer obtained by simply copolymerizing ethylene with propylene, if the ethylene content is low, the flexibility and impact resistance are not sufficient, so that these physical properties can be improved. Increasing the ethylene content not only makes the heat resistance extremely worse and difficult to manufacture, but also makes it difficult to meet all the required qualities.
Therefore, in the present invention, the propylene-ethylene block copolymer (A) is a block copolymer obtained by sequentially polymerizing components having different ethylene contents in the first step and the second step. Necessary to balance.
Further, since a copolymer having a low molecular weight and easily sticking alone may be used as the component (A2), the component (A2) is polymerized after the component (A1) is polymerized in order to prevent problems such as adhesion to the reactor. It is desirable to use a method of polymerizing).

(I) Sequential polymerization In producing the propylene-ethylene block copolymer (A) used in the present invention, a propylene homopolymer or a crystalline propylene-ethylene random copolymer component (A1) and a low crystallinity or It is necessary to sequentially polymerize the amorphous propylene-ethylene random copolymer component (A2) for the reasons described above.
When performing sequential polymerization, either a batch method or a continuous method can be used, but it is generally desirable to use a continuous method from the viewpoint of productivity.
In the case of a batch method, it is possible to polymerize component (A1) and component (A2) separately using a single reactor by changing the polymerization conditions with time. As long as the effects of the present invention are not impaired, a plurality of reactors may be connected in parallel.
In the case of the continuous method, since it is necessary to polymerize the component (A1) and the component (A2) separately, it is necessary to use a production facility in which two or more reactors are connected in series, but this hinders the effect of the present invention. As long as it does not, you may connect and use a some reactor in series and / or parallel about each of a component (A1) and a component (A2).

(Ii) Polymerization process As the polymerization process (polymerization method), any polymerization method such as a slurry method, a bulk method, and a gas phase method can be used. Although supercritical conditions can be used as intermediate conditions between the bulk method and the gas phase method, they are substantially the same as the gas phase method, and are therefore included in the gas phase method without particular distinction.
Since the low crystalline or amorphous propylene-ethylene random copolymer component (A2) is easily soluble in organic solvents such as hydrocarbons and liquefied propylene, it is desirable to use a gas phase method for the production of the component (A2).
The production of the crystalline propylene-ethylene random copolymer component (A1) has no particular problem no matter which process is used, but in the case of producing the component (A1) having a relatively low crystallinity, there are problems such as adhesion. In order to avoid this, it is desirable to use a gas phase method.
Therefore, using a continuous method, first, a propylene homopolymer or a crystalline propylene-ethylene random copolymer component (A1) is polymerized by a bulk method or a gas phase method, followed by low crystalline or amorphous propylene-ethylene. It is most desirable to polymerize the random copolymer elastomer component (A2) by a gas phase method.

(Iii) Other polymerization conditions The polymerization temperature can be used without any particular problem as long as it is within a commonly used temperature range. Specifically, a range of 0 ° C. to 200 ° C., more preferably 40 ° C. to 100 ° C. can be used. The polymerization pressure varies depending on the process to be selected, but it can be used without any problem as long as it is in a pressure range usually used. Specifically, a range of greater than 0 to 200 MPa, more preferably 0.1 MPa to 50 MPa can be used. At this time, an inert gas such as nitrogen can be coexisted.
When the component (A1) is sequentially polymerized in the first step and the component (A2) is sequentially polymerized in the second step, it is desirable to add a polymerization inhibitor to the system in the second step. In the case of producing a propylene-ethylene block copolymer, if a polymerization inhibitor is added to a reactor that performs ethylene-propylene random copolymerization in the second step, the particle properties (fluidity, etc.) of the resulting powder, gel, etc. Product quality can be improved. Various technical studies have been made on this technique, and examples thereof include JP-B 63-54296, JP-A 7-25960, and JP-A 2003-2939. It is desirable to apply the method to the present invention.

  In addition, each element of the propylene-ethylene block copolymer (A) used for the polypropylene film of the present invention is controlled as follows, and is required for the propylene-ethylene block copolymer (A) of the present invention. Can be manufactured to meet the structural requirements.

(A) Component (A1) For the crystalline propylene-ethylene random copolymer component (A1), it is necessary to control the ethylene content ([E] _A1 ) and the peak temperature T (A1).
In the present invention, in order to control [E] _A1 within a predetermined range, the amount ratio of propylene and ethylene supplied to the polymerization tank in the first step may be appropriately adjusted. The relationship between the supply ratio and the ethylene content in the resulting propylene-ethylene random copolymer varies depending on the type of metallocene catalyst used, but the component (A1) having the ethylene content [E] _A1 required by adjusting the supply ratio Can be manufactured. For example, when controlling [E] _A1 to 0 to 7% by weight, the supply weight ratio of ethylene to propylene may be in the range of 0 to 0.3, preferably in the range of 0 to 0.2.
At this time, the component (A1) has a narrow crystallinity distribution, and T (A1) decreases with an increase in [E] _A1 . Therefore, in order for T (A1) to satisfy the scope of the present invention, [E] _A1 and the relationship between these are grasped and adjusted to take the target range.

(B) Component (A2) For the low crystalline or amorphous propylene-ethylene random copolymer component (A2), ethylene content [E] _A2 and peak temperature T (A2), xylene-soluble intrinsic viscosity [ [η] cxs needs to be controlled.
In the present invention, in order to control [E] _A2 within a predetermined range, the ratio of ethylene supply to propylene in the second step may be controlled in the same manner as [E] _A1 . For example, when [E] _A2 is controlled to 5 to 20% by weight, the supply weight ratio of ethylene to propylene may be in the range of 0.01 to 5, preferably in the range of 0.05 to 2. At this time, although the crystallinity distribution of the component (A2) is slightly increased with the increase of the ethylene content, T (A2) is decreased with the increase of [E] _A2 as in the case of the component (A1).
Therefore, in order for T (A2) to satisfy the scope of the present invention, the relationship between [E] _A2 and T (A2) is grasped, and [E] _A2 is controlled to be within a predetermined range. Good.
[Η] cxs will be described later.

(C) About W (A1) and W (A2) The amount W (A1) of component (A1) and the amount W (A2) of component (A2) are the production amounts of the first step for producing component (A1). It can be controlled by changing the ratio of the production amount of the component (A2). For example, in order to increase W (A1) and reduce W (A2), the production amount of the second step may be reduced while maintaining the production amount of the first step, which shortens the residence time of the second step. It can be easily controlled by reducing the polymerization temperature or increasing the amount of the polymerization inhibitor. The reverse is also true.
Actually, when setting the conditions, it is necessary to consider the decay of activity. That is, in the range of the ethylene content [E] _A1 and [E] _A2 to be carried out in the present invention, when the ratio of ethylene supply to propylene is generally increased in order to increase the ethylene content, the polymerization activity is increased. At the same time, the activity decay tends to increase. Therefore, in order to maintain the activity of the second step, it is necessary to suppress the polymerization activity of the first step. Specifically, the production amount W (A1) is lowered in the first step, and the polymerization is performed as necessary. Lower the temperature and / or shorten the polymerization time (residence time), or increase the ethylene content [E] _A2 in the second step, increase the production W (A2), and raise the polymerization temperature as necessary And / or conditions may be set in such a way as to increase the polymerization time (residence time).

(D) Glass transition temperature Tg The propylene-ethylene block copolymer (A) used in the present invention preferably has a single peak in the glass transition temperature Tg. In order for Tg to have a single peak, the difference [E] gap of the ethylene content [E] _A1 in component (A1) and the ethylene content [E] _A2 in component (A2), ie [E ] _A2- [E] _{A1 is set} to 20% by weight or less, preferably 18% by weight, more preferably 15% by weight or less, and in actual measurement, [E] gap is reduced to a range where Tg becomes a single peak That's fine.
Depending on the ethylene content [E] _A1 of the crystalline copolymer component (A1), the ethylene content [E] _A2 of the low crystalline or amorphous copolymer component (A2) should be within the proper range. By setting the supply weight ratio of ethylene to propylene during the polymerization of component (A2), it is possible to obtain a polymer having a predetermined [E] gap.
Moreover, Tg of the propylene-ethylene block copolymer (A) which does not take a phase-separated structure as in the present invention is the ethylene content [E] _A1 in the component (A1) and the ethylene content in the component (A2). [E] _A2 and the amount ratio of both components are affected. In the present invention, the amount of the component (A2) is 5 to 70% by weight, but in this range, Tg is more strongly affected by the ethylene content [E] _{A2 in} the component (A2). That is, Tg reflects the glass transition of the amorphous part. In the block copolymer component (A) of the present invention, the component (A1) has crystallinity and relatively few amorphous parts. This is because the component (A2) is low crystalline or amorphous and most of it is an amorphous part.
Therefore, the value of Tg is controlled by substantially _{[E] A2,} the control method of _{[E] A2} are as described above.

(E) Melt Flow Rate (MFR) In the propylene-ethylene block copolymer (A) of the present invention, the crystalline copolymer component (A1) and the low crystallinity or Since the amorphous copolymer elastomer component (A2) is compatible, the viscosity [η] A1 of the component (A1), the viscosity [η] A2 of the component (A2), a propylene-ethylene block copolymer ( A) The apparent viscosity mixing rule generally holds between the overall viscosity [η] W. That is,
Log [η] W = {W (A1) × Log [η] A1 + W (A2) × Log [η] A2} / 100
Is generally established. In general, there is a certain correlation between MFR and [η], so from the viewpoint of flexibility and heat resistance, [η] A2, W (A1), and W (A2) are set first. The MFR can be freely controlled by changing [η] A1 according to the above equation.

(F) Elution temperature T (A4) The temperature T (A) at which 99% by weight is eluted is an index indicating the crystallinity distribution. Since T (A4) is closer to T (A1) (lower) as the crystallinity distribution of component (A1) is narrower, controlling (A4) lower is the crystal of component (A1) and component (A2). It is none other than controlling the sex distribution narrowly.
In general, by using a metallocene-based catalyst, a polymer having a narrower crystallinity distribution can be obtained than when using a Ziegler-Natta catalyst. In order to narrow the property distribution, a metallocene catalyst is used.

  Furthermore, in order to adjust the final propylene-ethylene block copolymer (A) to those having desirable physical properties, the components (A1) and (A2) have different specific polymer compositions. That is, in the first step and the second step, it is necessary to keep the polymerization conditions corresponding to the respective polymer compositions, particularly the monomer gas composition, at different specific values. Therefore, when the crystallinity distribution of the component (A2) is wide in the adopted process, the transfer step is adjusted so that the specific monomer gas mixture corresponding to the first step is not brought into the second step from the first step. It is necessary to devise such as. Specifically, the crystallinity distribution of the component (A2) can be narrowed by increasing the purge amount in the transfer step, or by diluting or substituting with an inert gas such as nitrogen.

(G) Component amount M (Mw ≦ 5,000) having a molecular weight of 5,000 or less Generally, a polymer having a narrower molecular weight distribution than that of a Ziegler-Natta catalyst can be obtained by using a metallocene catalyst. However, in a system performing sequential polymerization as in the present invention, it is not always sufficient to use a metallocene catalyst in order to narrow the molecular weight distribution. In particular, in order to prevent the formation of low molecular weight components, the time for transferring from the first step to the second step can be shortened, or the monomer gas mixture corresponding to the first step can be changed with an inert gas such as nitrogen in the transfer step. By completely replacing it, M (Mw ≦ 5,000) can be controlled to be small independently of the polymerization conditions.

(H) Intrinsic Viscosity [η] cxs For [η] cxs, the propylene-ethylene block copolymer (A) of the present invention uses a metallocene catalyst, so that the CXS component is mostly contained in component (A1). Therefore, it can be controlled by changing the molecular weight of the component (A2). In order to control [η] cxs, the ratio of hydrogen supply to the monomer in the second step may be controlled as usual. In general, a metallocene catalyst tends to have a lower molecular weight of the polymer as the polymerization temperature is higher. Therefore, [η] cxs can be controlled by changing the polymerization temperature. [Η] cxs can also be controlled by combining both the hydrogen supply ratio and the polymerization temperature.

2. Adhesive layer In the surface protective film of the present invention, an adhesive layer is formed on one surface of the base material layer made of the propylene-ethylene block copolymer (A).
As the pressure-sensitive adhesive, an ethylene / α-olefin copolymer (B) having the following characteristics (b1) to (b3) polymerized with a metallocene catalyst and (b4) as necessary is used.
By using a specific ethylene / α-olefin copolymer polymerized with a metallocene catalyst in the adhesive layer, at least one of the base material layer and the adhesive layer made of a propylene-ethylene copolymer resin polymerized with a metallocene catalyst is melted. When laminated in a state, it adheres firmly and has excellent delamination properties. Since the adhesive layer and the base material layer are firmly bonded, for example, after attaching the surface protective film of the present invention to a non-adherent, the adhesive layer does not remain on the non-adherent even if it is peeled off again. It can also be used as a surface protective film that can be repeatedly applied.

The α-olefin copolymerized with ethylene is preferably an α-olefin having 3 to 20 carbon atoms, and examples thereof include propylene, butene-1, hexene-1, octene-1, and the like. In particular, propylene, butene- 1 or hexene-1 is preferred. Further, the α-olefin copolymerized with ethylene may be one type or two or more types.
The ethylene content in the ethylene / α-olefin random copolymer is preferably 50% by weight or more. If the ethylene content is low, the adhesive strength tends to be weak, and therefore the effect as an adhesive layer may be inferior. The content of α-olefin is appropriately adjusted according to the required density.

(B1) the density of the density ethylene · alpha-olefin copolymer is 0.860~0.915g / cm ^3, preferably 0.870~0.910g / cm ^3, more preferably 0.880 to 0 908 g / cm ³ . The density is adjusted by the strength of the adhesive force. However, if the density is less than 0.860 g / cm ³ , the adhesive strength becomes too high, and there is a problem that the substrate film peels off and a mark remains on the protected object. If it exceeds / cm ³ , the adhesive strength becomes too weak and the effect as an adhesive layer cannot be obtained.
The density is a value measured according to JIS K6922-2: 1997 appendix (23 ° C.).

(B2) Elution amount of 20 ° C. or less by temperature rising elution fractionation (TREF) measurement Elution amount of 20 ° C. or less in temperature rising elution fractionation (TREF) measurement using orthodichlorobenzene of ethylene / α-olefin copolymer as a solvent is , 60% by weight or less, preferably 50% by weight or less, particularly preferably 15% by weight or less. If the amount of elution at 20 ° C. or less by TREF exceeds 60% by weight, the peeling strength at the time of feeding is large, and it is not preferable because it cannot be drawn out smoothly.
Further, the elution amount of 65 ° C. or higher by temperature rising elution fractionation (TREF) of the ethylene / α-olefin copolymer is preferably 0.3% by weight or more, more preferably 1.0% by weight or more, and further preferably 2%. 0.0% by weight or more, particularly preferably 5.0% by weight or more. If it is the said range, since favorable adhesive strength can be maintained, it is preferable.

Here, the amount of elution by TREF is measured by the following cross-fractionation chromatograph (CFC) comprising a temperature rising elution fractionation (TREF) part for performing crystalline fractionation and a gel permeation chromatography (GPC) part for molecular weight fractionation. Depending on the method.
First, a polymer sample was completely dissolved in orthodichlorobenzene (ODCB) containing 0.5 mg / mL BHT at 140 ° C., and this solution was passed through a sample loop of the apparatus, and the TREF column (not used) maintained at 140 ° C. Column) packed with active glass bead carriers) and gradually cooled to a predetermined first elution temperature to crystallize the polymer sample. After maintaining at a predetermined temperature for 30 minutes, ODCB is passed through a TREF column, whereby the eluted components are injected into the GPC section to perform molecular weight fractionation, and an infrared detector (MIRAN 1A IR detector manufactured by FOXBORO, A chromatogram is obtained with a measuring wavelength of 3.42 μm). Meanwhile, in the TREF part, the temperature is raised to the next elution temperature, and after obtaining the chromatogram of the first elution temperature, the elution component at the second elution temperature is injected into the GPC part. Thereafter, the same operation is repeated to obtain a chromatogram of the eluted components at each elution temperature.

The measurement conditions are shown below.
Equipment: CFC-T102L manufactured by Dia Instruments
GPC column: Showa Denko AD-806MS (3 connected in series)
Solvent: ODCB
Sample concentration: 3 mg / mL
Injection volume: 0.4mL
Crystallization rate: 1 ° C / min Solvent flow rate: 1 mL / min GPC measurement time: 34 minutes Stabilization time after GPC measurement: 5 minutes Elution temperature: 0, 5, 10, 15, 20, 25, 30, 35, 40, 45 49, 52, 55, 58, 61, 64, 67, 70, 73, 76, 79, 82, 85, 88, 91, 94, 97, 100, 102, 120, 140
Data analysis: The chromatograms of the elution components obtained at each elution temperature obtained by measurement are processed by the data processing program attached to the instrument, and the elution amount is standardized so that the total is 100% (proportional to the area of the chromatogram) ) Is required. In addition, an integrated elution curve for the elution temperature is calculated. An elution amount of 20 ° C. or lower and an elution amount of 65 ° C. or higher are determined from the obtained elution curve.

(B3) Ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / Mn)
The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the ethylene / α-olefin copolymer is 3.5 or less, preferably 3.0 to 1.5. Especially preferably, it is 2.5-2.0. If Mw / Mn exceeds 3.5, stickiness may occur.
Here, Mw / Mn is defined by the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC). The measuring method of Mw / Mn is as follows.
Apparatus: Waters GPC 150C type Detector: MIRAN 1A infrared spectrophotometer (measurement wavelength, 3.42 μm)
Column: 3 AD806M / S manufactured by Showa Denko Co., Ltd. The column was calibrated by measuring monodisperse polystyrene (0.5 mg / ml solution of each of A500, A2500, F1, F2, F4, F10, F20, F40, and F288) manufactured by Tosoh. And the logarithm of the elution volume and molecular weight was approximated by a quadratic equation. The molecular weight of the sample was converted to polyethylene using the viscosity formula of polystyrene and polyethylene. Here, the coefficients of the viscosity formula of polystyrene are α = 0.723 and log K = −3.767, and polyethylene has α = 0.723 and log K = −3.407.
Measurement temperature: 140 ° C
Injection volume: 0.2ml
Concentration: 20 mg / 10 mL
Solvent: Orthodichlorobenzene Flow rate: 1.0 ml / min

(B4) MFR
The melt flow rate (MFR: 190 ° C., 21.18N load) of the ethylene / α-olefin copolymer is preferably from 0.1 to 50 g / 10 minutes, more preferably from 1 to 30 g / 10 minutes, particularly preferably. Is 2 to 15 g / 10 min. When the MFR is less than 0.1 g / 10 min, the extrusion characteristics are liable to deteriorate, and there is a problem in that the interface with the base film of the propylene-ethylene block copolymer of the present invention is roughened. If it exceeds 50 g / 10 min, it causes thickness unevenness.
In addition, MFR of an ethylene polymer is a value measured based on JIS-K6922-2: 1997 appendix (190 degreeC, 21.18N load).

  The ethylene / α-olefin copolymer is obtained by using a metallocene catalyst in a process such as a gas phase method, a solution method, a high pressure method, a slurry method, etc., with ethylene and propylene, 1-butene, 1-hexene, 4-methyl-1- Although it can be produced by copolymerization with an α-olefin such as pentene and 1-octene, those produced by a high-pressure method or a solution method are particularly preferable because both the molecular weight distribution and the crystallinity distribution are narrow.

In the ethylene / α-olefin copolymer, MFR, density, elution amount of TREF 20 ° C. or lower, Mw / Mn change the polymerization temperature, polymerization pressure, catalyst used, and the type and composition of ethylene and α-olefin. Therefore, it can be adjusted easily.
For example, the density tends to increase as the polymerization temperature is increased, reducing the α-olefin feed rate. Moreover, the amount of elution below TREF 20 ° C. tends to increase as the α-olefin supply amount is increased or the polymerization temperature is lowered. Furthermore, the MFR tends to decrease with increasing polymerization pressure.

  The adhesive layer is composed mainly of an ethylene / α-olefin copolymer polymerized using the metallocene catalyst, but may contain only the ethylene / α-olefin copolymer, and may contain other components. May be. Examples of other components include low density polyethylene, hydrogenated styrene elastomer, and propylene soft resin.

Commercially available ethylene / α-olefin copolymers polymerized using a metallocene catalyst include Harmolex series, Kernel series, Prime polymer Evolue series, Sumitomo Chemical (Japan Polyethylene Co., Ltd.) Exelen GMH series, Exelen FX series, etc. manufactured by Co., Ltd. can be exemplified.
These pressure-sensitive adhesives can be used singly or in combination of two or more, as long as the effects of this object are not impaired. Moreover, other components can further be contained.

The adhesive layer is an ethylene / α-olefin obtained by polymerizing the propylene-ethylene block copolymer (A) used in the present invention with the metallocene catalyst in consideration of adhesion to the base material layer and heat resistance. What was mix | blended with the copolymer (B) can also be used as an adhesion layer. When the ethylene / α-olefin copolymer (B) polymerized using the metallocene catalyst is blended with the propylene-ethylene block copolymer (A) used in the present invention, the propylene-ethylene block copolymer is used. When the total of the combination (A) and the ethylene / α-olefin copolymer (B) is 100% by weight, the content of the propylene-ethylene block copolymer (A) is 1 to 49% by weight.
Among the other components that may be added to the adhesive layer, propylene-based soft resins include Dow Chemical Japan's “Versify” series, ExxonMobil's “Vistamax” series and Mitsui Chemicals, Inc. ) “Notio” series and the like, and as the hydrogenated styrene-based elastomer, “Dynalon” series made by JSR Corporation and the like can be exemplified, but are not limited thereto.

3. Release treatment layer In the surface protective film of the present invention, a release treatment layer is formed on the other surface of the pressure-sensitive adhesive layer formed on one of the base material layers made of the propylene-ethylene block copolymer. As a peeling process layer, the layer which roughened the peeling process layer side surface of a film, formed unevenness | corrugation, and improved peelability can be mentioned. Roughening the surface of the release treatment layer means that the film for surface protection has the characteristics that when the roll is unwound, the adhesive layer and the release treatment layer both come into contact with each other in a solid state, and when the roll is unwound, it is peeled off smoothly and when used it is improved. It can be.

The surface of the film that has been roughened on the surface of the release treatment layer to form unevenness to improve the peelability is based on the center surface average roughness of the release treatment layer surface (SRa, JIS B0651 (2001)). The resin used is not particularly limited as long as it is within the range of 0.2 to 1.5 μm (measured in the MD direction of the film with a measuring instrument), and is a known thermoplastic resin or thermosetting. Or a mixture thereof.
Preferably, a layer made of a polyolefin resin is good, specifically, a propylene / α-olefin block copolymer alone, or a propylene homopolymer blended with a propylene / α-olefin block copolymer, or , Propylene / α-olefin random copolymer blended with propylene / α-olefin block copolymer, low density polyethylene alone, high density polyethylene alone, or low density polyethylene blended with high density polyethylene Or a blend of low density polyethylene or high density polyethylene with a propylene homopolymer, or a blend of low density polyethylene or high density polyethylene with a propylene / α-olefin random copolymer, or propylene / α-ole A blend of low-density polyethylene or high-density polyethylene in a block copolymer, or a blend of two or more of these polyolefin resins, or a blend of thermoplastic resins with different compatibility with these polyolefin resins Can be mentioned.

In order to roughen the film surface to form irregularities and improve the peelability, the irregularities on the film surface are 0.2 to 1.5 μm in terms of center plane average roughness (SRa). Preferably it is 0.3-1.2 micrometers, More preferably, it is 0.5-1.0 micrometer, Most preferably, it is 0.8-1.0 micrometer. When the center surface average roughness is less than 0.2 μm, sufficient peeling performance cannot be exhibited, and when it exceeds 1.5 μm, the unevenness of the peeling surface is easily transferred to the adhesive layer, which is not preferable.
Here, the measuring method of the center plane average roughness (SRa) is measured by a stylus type surface roughness measuring instrument defined in JIS B0651 (2001) in the present invention. The measurement conditions of the measuring instrument are: the radius of curvature of the stylus tip is 5 μm, the cutoff wavelength is 0.80 mm, the cutoff type is 2CR (phase compensation), the measurement speed is 0.3 mm / second, the measurement direction is the film MD direction, and the measurement The length was 2 mm, and the range of surface roughness was defined by the obtained value. The MD direction as the measurement direction refers to the film feed direction (take-off direction) when the film of the present invention is produced by extrusion molding or the like, that is, the direction parallel to the longitudinal direction of the film.

Polyolefin resins preferably used for the release treatment layer include polypropylene resins such as propylene homopolymer (homopolypropylene), propylene / α-olefin random copolymer, propylene / α-olefin block copolymer, and high-pressure radical polymerization method. Examples thereof include low density polyethylene such as low density polyethylene and linear low density polyethylene, and polyethylene resins such as high density polyethylene.
Polypropylene resins such as propylene homopolymer (homopolypropylene), propylene / α-olefin random copolymer, propylene / α-olefin block copolymer generally use a catalyst such as a Ziegler catalyst or a metallocene catalyst. In the presence of these catalysts, it is produced by a polymerization method such as a slurry method using an inert solvent, a solution method, a gas phase method substantially using no solvent, or a bulk polymerization method using a polymerization monomer as a solvent. . Moreover, ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene etc. are mentioned as an alpha olefin of a copolymerization component. The α-olefin may be used alone or in combination of two or more.
High-density polyethylene generally uses a catalyst such as a Ziegler catalyst, a Phillips catalyst, or a metallocene catalyst, and is a process such as a gas phase method, a solution method, a high-pressure method, or a slurry method. It is produced by (co) polymerizing with α-olefins such as -butene, 1-hexene, 4-methyl-1-pentene, 1-octene.
High-pressure radical polymerization method Low-density polyethylene uses ethylene or ethylene and a small amount of propylene, 1-butene, 1-hexene, 4-methyl in a process such as a high-pressure radical polymerization method using a radical generator such as peroxide as a polymerization initiator. It is produced by (co) polymerizing α-olefins such as -1-pentene and 1-octene.
Linear low-density polyethylene generally uses a catalyst such as a Ziegler catalyst, a Phillips catalyst, or a metallocene catalyst, and processes such as a gas phase method, a solution method, a high-pressure method, and a slurry method with ethylene and propylene, 1-butene. , 1-hexene, 4-methyl-1-pentene, 1-octene and other α-olefins are copolymerized. The α-olefin may be used alone or in combination of two or more.
The low density polyethylene is preferably a high pressure radical polymerization method low density polyethylene from the viewpoint of moldability.

  Moreover, the said polyolefin resin preferably used for a peeling process layer can use the resin composition which combined single or 2 types or more of polyolefin resin. The blending amount and basic physical properties of the resin are not particularly limited as long as the center plane average surface roughness (SRa) of the surface of the release treatment layer of the film of the present invention is in the range of 0.2 to 1.5 μm. In the combination of polyethylene and high density polyethylene, preferably low density polyethylene 99-1% by weight, high density polyethylene 1-99% by weight, more preferably low density polyethylene 95-20% by weight, high density polyethylene 5-80% by weight. %, More preferably, a polyethylene resin composition containing 90 to 50% by weight of low density polyethylene and 10 to 50% by weight of high density polyethylene. The melt flow rate (MFR; based on JIS-K6922-2: 1997, measured at 190 ° C. and 21.18 N load) of the polyethylene-based resin is 0.1 to 40 g / 10 minutes, preferably 0.3. -25 g / 10 min, more preferably 1.0-10 g / 10 min.

Also, polypropylene resins such as propylene homopolymer (homopolypropylene), propylene / α-olefin random copolymer, propylene / α-olefin block copolymer, high pressure radical polymerization method low density polyethylene, linear low density When using as a release treatment layer by mixing a low density polyethylene such as polyethylene, or a polyethylene resin such as high density polyethylene, preferably 99 to 50% by weight of polypropylene resin, 1 to 50% by weight of polyethylene resin, More preferably, the resin composition contains 95 to 70% by weight of a polypropylene resin and 5 to 30% by weight of a polyethylene resin.
Further, in the combination of polypropylene resins such as a propylene homopolymer (homopolypropylene), a propylene / α-olefin random copolymer, and a propylene / α-olefin block copolymer, the polypropylene homopolymer 99 to 1 is preferable. Resin composition containing 1 to 99% by weight of propylene / α-olefin block copolymer, more preferably 95 to 5% by weight of propylene homopolymer and 5 to 95% by weight of propylene / α-olefin block copolymer More preferably, it is a resin composition containing 50 to 10% by weight of a propylene homopolymer and 50 to 90% by weight of a propylene / α-olefin block copolymer. Further, 99 to 1% by weight of propylene / α-olefin random copolymer, 1 to 99% by weight of propylene / α-olefin block copolymer, more preferably 95 to 5% by weight of propylene / α-olefin random copolymer. , A resin composition containing 5 to 95% by weight of propylene / α-olefin block copolymer, more preferably 50 to 10% by weight of propylene / α-olefin random copolymer, propylene / α-olefin block copolymer 50 It is a resin composition containing -90 weight%.

  Melt flow rate (MFR; JIS K7210-) of polypropylene resins such as propylene homopolymer (homopolypropylene), propylene / α-olefin random copolymer, propylene / α-olefin block copolymer, and the like preferably used for the release treatment layer According to 1995, the value measured at 230 ° C. and a load of 21.18 N is a melt flow rate (MFR) close to that of the propylene-based resin used for the base material layer in order to suppress interface roughness with the base material layer. Preferably, the melt flow rate (MFR) is from 1 to 50 g / 10 minutes, preferably from 2 to 30 g / 10 minutes, more preferably from 5 to 20 g / 10 minutes, most preferably from 7 to 15 g / 10. Minutes. Further, polypropylene resins such as propylene homopolymer (homopolypropylene), propylene / α-olefin random copolymer, propylene / α-olefin block copolymer used for the release treatment layer, and high-pressure radical polymerization method low density polyethylene In combination with a low-density polyethylene such as linear low-density polyethylene or a polyethylene resin such as high-density polyethylene, the melt flow rate (MFR) of the polypropylene resin and the melt flow rate (MFR of polyethylene resin) (JIS K6922). -2: In accordance with 1997, the value measured at 190 ° C. and a 21.18 N load) is extremely poor in compatibility with the MFR, and causes fish eyes. Melt flow rate (MFR) is 0.1-40 / 10 min, preferably 0.3～25G / 10 min, more preferably at 1.0～10G / 10 min.

    The low density polyethylene preferably used for the release treatment layer has a ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) of 4. It is preferably 0 to 8.0. When Mw / Mn is 4.0 to 8.0, the outer layer (release treatment layer) -adhesive delamination property is excellent.

In particular, the polyolefin resin and the like preferably used for the release treatment layer preferably has a D hardness of 50 or more in order to prevent the film surface from being damaged during transportation and transportation.
Here, the D hardness is a value measured according to JIS K7215.

Since the D hardness of the polyolefin resin is listed in a product pamphlet created by a polyolefin resin manufacturer or a polyolefin resin sales company, it can be selected from those commercially available products. The D hardness of a resin composition in which two or more polyolefin resins are combined can be predicted by an addition rule calculation from the D hardness and composition ratio of each polyolefin resin. In general, the D hardness is considered to change according to the crystallinity of the polyolefin resin. Among the polyolefin-based resins, the polyethylene-based resin has a high density polyethylene and tends to decrease as the density decreases. Moreover, propylene homopolymer is high in a propylene-type resin, and it becomes low as the quantity of a copolymerization component increases.
In the present invention, it is preferable to select in consideration of other performances (formability, interlayer strength with intermediate layer, etc.) within a range where D hardness is 50 or more.

  Further, when a release treatment agent such as a silicone type or a long chain alkyl type is used in combination with the release treatment layer, a smooth feeling when the roll is unwound is improved, and a further feeding effect is obtained.

  As the silicone release treatment agent, a commonly used silicone release treatment agent mainly composed of dimethylpolysiloxane can also be used. It is also possible to use a silicone release treatment agent containing a three-dimensional organopolysiloxane. Specifically, a silicone-based release treatment agent containing organopolysiloxane as a main component and blended with a cellulose derivative such as methyl cellulose, ethyl cellulose, acetyl cellulose, alkyd resin, or the like is preferably used. By incorporating a cellulose derivative, an alkyd resin, or the like, the releasability of the silicone release treatment agent can be controlled. The cellulose derivative and alkyd resin are preferably blended in an amount of 5 to 50% by weight in the silicone-based release treatment agent.

Organopolysiloxanes are roughly classified into a condensation reaction type and an addition reaction type depending on the type of the curing reaction (crosslinking reaction), but any reaction type may be used in the present invention.
For example, as the condensation reaction type silicone release agent, for example, a silicone release agent in which a cellulose derivative or an alkyd resin is blended with an organopolysiloxane having a silanol group at a molecular terminal is mentioned. Here, as the organopolysiloxane having a silanol group at the molecular end, a polysiloxane in which an alkyl group such as a methyl group or an ethyl group or a phenyl group is introduced as a side chain functional group (for example, dimethyl diphenylpolysiloxane) is used. It is preferable that the release agent has a good compatibility with the cellulose derivative and the alkyd resin, and a stable release property. In addition, the organopolysiloxane having a silanol group at the molecular end is appropriately blended with a crosslinking agent such as an alkoxy group-containing organopolysiloxane, or a catalyst such as dibutyltin dilaurate, dibutyltin diacetate, dibutylditin dioctate, or zinc octylate. May be. Moreover, resin, such as an acrylic resin, can also be suitably mix | blended as a 3rd component as needed. In the silicone release agent, the crosslinking agent is preferably 4 to 20% by weight, the catalyst is preferably 5 to 10% by weight, and the resin as the third component is preferably 5 to 26% by weight.

  As an addition reaction type silicone release agent, for example, a silicone release agent in which a cellulose derivative or an alkyd resin is blended with an organopolysiloxane having at least two alkenyl groups such as vinyl groups bonded to silicon atoms in one molecule. Agents. Here, as the above-mentioned organopolysiloxane, it is preferable to use an organopolysiloxane having an alkyl group such as a methyl group or an ethyl group or a phenyl group introduced as a functional group of the side chain, whereby cellulose derivatives or alkyds are used. A release agent having good compatibility with the resin and stable release characteristics can be obtained. The organopolysiloxane may be appropriately blended with a crosslinking agent such as an organohydrodiene polysiloxane and a catalyst such as a platinum compound such as chloroplatinic acid.

  The silicone-based release treatment agent can be appropriately selected from commercially available products. For example, as a condensation reaction type silicone release agent, KS available from Shin-Etsu Chemical Co., Ltd., KS -723A / B (consisting of dimethyl-diphenylpolysiloxane, methoxysilicone and ethylcellulose) is X-62-9201A / B available from Shin-Etsu Chemical Co., Ltd. as an addition reaction type silicone release agent. be able to.

Examples of the long-chain alkyl release agent include a polymer of a long-chain alkyl acrylate having 12 or more carbon atoms, a copolymer of a long-chain alkyl acrylate and another vinyl monomer, or a long-chain alkyl isocyanate to polyvinyl alcohol. And a release agent obtained from a reaction product obtained by reacting the long-chain alkyl component.
For example, BP type manufactured by Nitto Denko Corporation, ashioresin manufactured by Ashio Sangyo Co., Ltd., and Pyroleil manufactured by Yushi Co., Ltd. can be used.

As a means of using a release treatment agent such as a silicone or a long chain alkyl type in combination with the release treatment layer, a method of applying and curing to the release treatment layer by a known method, a blending with a release treatment layer resin in advance, etc. A method can be mentioned.
As a method of applying to the release treatment layer, on the surface of the release treatment layer, a silicone or long chain alkyl release agent dissolved in an organic solvent such as a toluene solution is applied with a roll coater and then dried. A method of curing the release treatment agent to form a release treatment layer can be mentioned. At this time, in order to improve the affinity, the surface of the release treatment layer may be subjected to conventionally known corona discharge treatment, plasma discharge treatment, primer treatment, and the like.
In addition, as a method of blending in advance in the release treatment layer, by using an extruder, a release treatment agent such as silicone or long chain alkyl is blended in the release treatment layer resin and heated and melted, and in a film form from the T die, Examples thereof include a method of laminating on one side of the base material layer, or a method of heat-melting with an extruder and co-extrusion into a film form from a T-die together with the base material layer.

  In the present invention, when a silicone-based or long-chain alkyl-based release treatment agent is blended into a release treatment layer resin and a method of co-extrusion formation with a base layer from a T-die is adopted, there is a problem of contamination and economics. This is advantageous.

In the case of a method in which a silicone-based or long-chain alkyl-based release treatment agent is applied in a subsequent step to form a release treatment resin layer, the application amount of the release treatment agent is usually 0.01 to 10 g / m ² , preferably 0.5 to 0.7 g / m ² , more preferably 0.1 to 0.4 g / m ² . In the case of long-chain alkyl-based, 0.005~10g / ^{m 2,} preferably 0.02~0.3g / ^{m 2,} particularly preferably preferably 0.01 to 0.1 g / ^{m 2.}
In addition, in the case of a method for forming a release treatment layer obtained by blending a release treatment agent into a release treatment layer resin and heating and melting from an extruder, the amount of the release treatment agent is the sum of the release treatment layer resin and the release treatment agent. Is 100% by weight, the content of the release treatment layer resin is 90 to 99.95% by weight, and the content of the release treatment agent is 10 to 0.05% by weight. Preferably, the content of the release treatment layer resin is 95 to 99.9% by weight, and the content of the release treatment agent is 5 to 0.1% by weight.

4). Resin compounding agent that can be used in each layer The base material layer made of the propylene-ethylene block copolymer (A) in the present invention, the adhesive layer made of the ethylene / α-olefin copolymer (B), and the release treatment layer Various additives used as a known resin compounding agent within the range that does not impair the purpose of the present invention, from the film-forming stability of the film, the handling during secondary processing, and the quality maintenance as a surface protective film, for example, , Antioxidants, antiblocking agents, slip agents, nucleating agents, neutralizing agents, light stabilizers, antistatic agents, tackifiers and the like may be contained.
Various additives are described in detail below.

(1) Antioxidants As antioxidants, specific examples of phenolic antioxidants include tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, 1,1,3- Tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, pentaerythrityl-tetrakis {3- ( 3,5-di-tert-butyl-4-hydroxyphenyl) propionate}, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10- Examples thereof include tetraoxaspiro [5,5] undecane, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid and the like.

Specific examples of phosphorus antioxidants include tris (mixed, mono and dinonylphenyl phosphite), tris (2,4-di-t-butylphenyl) phosphite, 4,4′-butylidenebis (3- Methyl-6-tert-butylphenyl-di-tridecyl) phosphite, 1,1,3-tris (2-methyl-4-di-tridecylphosphite-5-tert-butylphenyl) butane, bis (2, 4-di-t-butylphenyl) pentaerythritol-di-phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t -Butyl-5-methylphenyl) -4,4'-biphenylenediphosphonite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phos You can list s fights.
Specific examples of the sulfur-based antioxidant include di-stearyl-thio-di-propionate, di-myristyl-thio-di-propionate, pentaerythritol-tetrakis- (3-lauryl-thio-propionate), and the like. it can.
These antioxidants can be used singly or in combination of two or more as long as the effects of the present object are not impaired.

  The compounding quantity of antioxidant is 0.01-1.0 weight part with respect to 100 weight part of each resin used for each layer of a base material layer, an adhesion layer, and a peeling process layer, Preferably it is 0.02-0. 5 parts by weight, more preferably 0.05 to 0.1 parts by weight. When the blending amount of the antioxidant is within the above range, the thermal stability is improved and the deterioration of the resin causing fish eyes is suppressed.

(2) Antiblocking agent As the antiblocking agent, those having an average particle diameter of 1 to 7 μm, preferably 1 to 5 μm, and more preferably 1 to 4 μm can be preferably used. If the average particle diameter is less than 1 μm, the slipperiness and openability of the resulting film are inferior. On the other hand, if it exceeds 7 μm, the transparency and scratching property are remarkably inferior. Here, the average particle diameter is a value obtained by Coulter counter measurement.

Specific examples of the anti-blocking agent include, for example, inorganic or synthetic silica (silicon dioxide), magnesium silicate, aluminosilicate, talc, zeolite, aluminum borate, calcium carbonate, calcium sulfate, barium sulfate, calcium phosphate. Etc. are used.
Moreover, as an organic type, polymethyl methacrylate, polymethylsilyltosesquioxane (silicone), polyamide, polytetrafluoroethylene, epoxy resin, polyester resin, benzoguanamine / formaldehyde (urea resin), phenol resin, etc. may be used. it can.
In particular, synthetic silica and polymethyl methacrylate are preferable from the balance of dispersibility, transparency, blocking resistance, and scratch resistance.
Anti-blocking agents may be surface-treated, and as surface treating agents, surfactants, metal soaps, acrylic acids, oxalic acid, citric acid, tartaric acid and other organic acids, higher alcohols, esters , Silicone, fluorine resin, silane coupling agent, hexametaphosphate soda, pyrophosphate soda, tripolyphosphate soda, trimetaphosphate soda, etc. can be used, especially citric acid treatment among organic acid treatment Those are preferred. The treatment method is not particularly limited, and a known method such as surface spraying or dipping can be employed.
The anti-blocking agent may have any shape, and may be any shape such as a spherical shape, a square shape, a column shape, a needle shape, a plate shape, or an indefinite shape.
These anti-blocking agents can be used singly or in combination of two or more in a range that does not impair the effects of this object.

  When the antiblocking agent is blended, the blending amount is 0.01 to 1.0 part by weight with respect to 100 parts by weight of each resin used in each of the base layer, the adhesive layer and the release treatment layer, preferably 0.00. It is 05-0.7 weight part, More preferably, it is 0.1-0.5 weight part. When the blending amount of the anti-blocking agent is within the above range, the blocking property is improved and the feeding property is improved.

(3) Slip agent Examples of the slip agent include monoamides and bisamides, and these may be substituted. Among these, it can be used 1 type or in combination of 2 or more types.
Specific examples of monoamides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide and the like as saturated fatty acid monoamides.
Examples of the unsaturated fatty acid monoamide include oleic acid amide, erucic acid amide, ricinoleic acid amide and the like.
Specific examples of substituted amides among monoamides include N-stearyl stearic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl Examples include palmitic acid amide.
Specific examples of bisamides include, as saturated fatty acid bisamides, methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis lauric acid amide, ethylene bis stearic acid amide, ethylene bisisostearic acid amide, ethylene bishydroxystearic acid amide, Ethylene bis behenic acid amide, hexamethylene bis stearic acid amide, hexamethylene bis behenic acid amide, hexamethylene bishydroxy stearic acid amide, N, N'-distearyl adipic acid amide, N, N'-distearyl Sepacic acid amide etc. are mentioned.
Examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide and hexamethylene bisoleic acid amide.
Examples of the aromatic bisamide include m-xylylene bis stearic acid amide and N, N′-distearylisophthalic acid amide.
Among these, oleic acid amide, erucic acid amide, and behenic acid amide are particularly preferably used among the fatty acid amides.
Specific examples of substituted amides among bisamides include N, N′-dioleyl adipate amide, N, N′-dioleyl sepasin amide, and the like.
Examples of the aromatic bisamide include m-xylylene bis stearic acid amide and N, N′-distearylisophthalic acid amide.
Among these, oleic acid amide, erucic acid amide, and behenic acid amide are particularly preferably used among the fatty acid amides.

  The amount of the slip agent to be blended is 0.01 to 1.0 part by weight, preferably 0 with respect to 100 parts by weight of each resin used for each of the base layer, the adhesive layer and the release treatment layer. 0.05 to 0.7 parts by weight, more preferably 0.1 to 0.4 parts by weight. When the blending amount of the slip agent is within the above range, the slipping property is improved and the feeding property is improved.

(4) Nucleating agent Specific examples of the nucleating agent include sodium 2,2-methylene-bis (4,6-di-t-butylphenyl) phosphate, talc, 1,3,2,4-di (p-methyl). A sorbitol-based compound such as benzylidene) sorbitol, hydroxy-di (t-butylaluminum benzoate), 2,2-methylene-bis (4,6-di-t-butylphenyl) phosphoric acid and an aliphatic monocarbon having 8 to 20 carbon atoms A carboxylic acid lithium salt mixture (manufactured by ADEKA, trade name NA21) and the like can be mentioned.
The blending amount when blending the nucleating agent is 0.0005 to 0.5 parts by weight, preferably 100 parts by weight of each resin used for each layer of the base material layer, the adhesive layer and the release treatment layer. It is 0.001-0.1 weight part, More preferably, it is 0.005-0.05 weight part. When the blending amount of the nucleating agent is within the above range, the crystallization speed is increased and the transparency is improved.

Moreover, a high density polyethylene resin can be mentioned as a nucleating agent other than the above. The density of the high-density polyethylene resin is 0.94 to 0.98 g / cm ³ , preferably 0.95 to 0.97 g / 10 cm ³ . If the density is out of this range, the effect of improving transparency cannot be obtained. The 190 degreeC melt flow rate (MFR) of a high density polyethylene resin is 5 g / 10min or more, Preferably it is 7-500 g / 10min, More preferably, it is 10-100 g / 10min. When the MFR is less than 5 g / 10 min, the dispersion diameter of the high-density polyethylene resin is not sufficiently small, and it itself becomes a foreign matter and causes fish eyes. In order to finely disperse the high-density polyethylene resin, the MFR of the high-density polyethylene resin is preferably larger than the MFR of the propylene-ethylene block copolymer used in the present invention.

  The production of the high-density polyethylene resin used as the nucleating agent is not particularly limited with respect to the polymerization method and catalyst as long as a polymer having the desired physical properties can be produced. For catalysts, Ziegler type catalysts (ie, based on a combination of supported or unsupported halogen-containing titanium compounds and organoaluminum compounds), Kaminsky type catalysts (ie, supported or unsupported metallocene compounds and organoaluminum compounds, especially alumoxanes). Based on the combination). There is no restriction | limiting about the shape of a high density polyethylene-type resin, A pellet form may be sufficient and a powder form may be sufficient.

  When used as a nucleating agent, the blending amount of the high-density polyethylene is 0.01 to 5 parts by weight, preferably 100 parts by weight of each resin used in each layer of the base material layer, the adhesive layer and the release treatment layer. 0.05 to 3 parts by weight, more preferably 0.1 to 1 part by weight. When the blending amount of the high density polyethylene is within the above range, the crystallization speed is increased and the transparency is improved. Further, in the case of coextrusion molding, there is no transfer of the sweeper roll.

(5) Neutralizing agent Specific examples of the neutralizing agent include calcium stearate, zinc stearate, hydrotalcite, Mizukarak (manufactured by Mizusawa Chemical Co., Ltd.), and the like.
The blending amount in the case of blending the neutralizing agent is 0.01 to 1.0 part by weight, preferably 0.00 with respect to 100 parts by weight of each resin used in each of the base layer, the adhesive layer and the release treatment layer. It is 02-0.5 weight part, More preferably, it is 0.05-0.1 weight part. When the blending amount of the neutralizing agent is within the above range, the effect as an internal lubricant is improved, and scraping of deteriorated materials inside the extruder is suppressed.

(6) Light Stabilizer As the light stabilizer, a hindered amine stabilizer is preferably used, and a structure in which all hydrogen bonded to carbons at the 2-position and 6-position of a conventionally known piperidine is substituted with a methyl group. Although the compound which has this is used without being specifically limited, the following compounds are specifically used.
Specific examples include polycondensates of dimethyl oxalate and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, tetrakis (1,2,2,6,6). -Pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, N, N-bis (3-aminopropyl) ) Ethylenediamine · 2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4- Jil} {(2,2, , 6-tetramethyl-4-piperidyl) imino} hexamethylene {2,2,6,6-tetramethyl-4-piperidyl} imino], poly [(6-morpholino-s-triazine-2,4-diyl) And [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}].
These hindered amine stabilizers can be used singly or in combination of two or more in a range not impairing the effect of the present object.

When the hindered amine stabilizer is blended, the blending amount is 0.005 to 2 parts by weight, preferably 0.01 to 100 parts by weight of each resin used in each layer of the base material layer, the adhesive layer and the release treatment layer. -1 part by weight, more preferably 0.05-0.5 part by weight.
When the content of the hindered amine stabilizer is within the above range, stability such as heat resistance and aging resistance is improved.

(7) Antistatic agent The antistatic agent can be used without particular limitation as long as it is a known antistatic agent or antistatic agent conventionally used, and examples thereof include anionic surfactants and cations. Ionic surfactants, nonionic surfactants, amphoteric surfactants and the like.

  Examples of the anionic surfactant include fatty acid or rosin acid soap, N-acyl carboxylate, ether carboxylate, carboxylate such as fatty acid amine salt; sulfosuccinate, ester sulfonate, N-acyl sulfonate Sulfonates such as salts; sulfated oils, sulfate esters, alkyl sulfate salts, sulfate sulfate polyoxyethylene salts, sulfate ether salts, sulfate ester salts such as sulfate amide salts; alkyl phosphate salts, alkyl polyoxyethylene phosphates Examples thereof include phosphoric acid ester salts such as salts, phosphoric acid ether salts and phosphoric acid amide salts.

  Examples of the cationic surfactant include amine salts such as alkylamine salts; alkyltrimethylammonium chloride, alkylbenzyldimethylammonium chloride, alkyldihydroxyethylmethylammonium chloride, dialkyldimethylammonium chloride, tetraalkylammonium salt, N, N-di Quaternary ammonium salts such as (polyoxyethylene) dialkylammonium salts and N-alkylalkanamide ammonium salts; 1-hydroxyethyl-2-alkyl-2-imidazoline, 1-hydroxyethyl-1-alkyl-2-alkyl Examples include alkyl imidazoline derivatives such as -2-imidazoline; imidazolinium salts, pyridinium salts, isoquinolinium salts, and the like.

  Examples of the nonionic surfactant include ether forms such as alkyl polyoxyethylene ether and p-alkylphenyl polyoxyethylene ether; fatty acid sorbitan polyoxyethylene ether, fatty acid sorbitol polyoxyethylene ether, fatty acid glycerin polyoxyethylene ether, etc. Ether ester form of fatty acid polyoxyethylene ester, monoglyceride, diglyceride, sorbitan ester, sucrose ester, dihydric alcohol ester, boric acid ester, etc .; dialcohol alkylamine, dialcohol alkylamine ester, fatty acid alkanolamide, N, N-di (polyoxyethylene) alkanamide, alkanolamine ester, N, N-di (polyoxyethylene) alkaneamine, amine oxy De, a nitrogen-formed and fabricated and alkyl polyethylene imine.

  Examples of the amphoteric surfactant include amino acid forms such as monoaminocarboxylic acid and polyaminocarboxylic acid; N-alkyl-β-alanine such as N-alkylaminopropionate and N, N-di (carboxyethyl) alkylamine salt. Forms: Betaine forms such as N-alkylbetaines, N-alkylamidobetaines, N-alkylsulfobetaines, N, N-di (polyoxyethylene) alkylbetaines, imidazolinium betaines; 1-carboxymethyl-1-hydroxy- And alkyl imidazoline derivatives such as 1-hydroxyethyl-2-alkyl-2-imidazoline and 1-sulfoethyl-2-alkyl-2-imidazoline.

  Among these, nonionic surfactants and amphoteric surfactants are preferable. Among them, monoglycerides, diglycerides, boric acid esters, dialcohol alkylamines, dialcohol alkylamine esters, amides and the like or nitrogen-containing non-type surfactants are preferred. Ionic surfactants; betaine amphoteric surfactants are preferred.

  In addition, as an antistatic agent, a commercial item can be used, for example, electro stripper TS5 (trade name, glycerin monostearate manufactured by Kao Corporation), electro stripper TS6 (trade name, stearyl manufactured by Kao Corporation). Diethanolamine), electrostripper EA (trade name, lauryl diethanolamine, manufactured by Kao Corporation), electrostripper EA-7 (trade name, polyoxyethylene laurylamine capryl ester, manufactured by Kao Corporation), Denon 331P (maruhishi oil ( Co., Ltd., trademark, stearyl diethanolamine monostearate), Denon 310 (manufactured by Maruhishi Oil Chemical Co., Ltd., trademark, alkyldiethanolamine fatty acid monoester), Register PE-139 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trademark) , Stearic acid mono & diglyceride Ester), Chemistat 4700 (Sanyo Chemical Industries Co., Ltd., trademark, alkyl dimethyl betaine), rheostat S (Lion Co., Ltd., trademark, alkyl diethanolamide), and the like.

  When blending the antistatic agent, the blending amount is 0.01 to 2 parts by weight, preferably 0.05 with respect to 100 parts by weight of each resin used in the base layer, the adhesive layer and the release treatment layer. To 1 part by weight, more preferably 0.1 to 0.8 part by weight, and most preferably 0.2 to 0.5 part by weight. These antistatic agents can be used singly or in combination of two or more in a range that does not impair the effects of this object. When the blending amount of the antistatic agent is within the above range, it is possible to prevent electrification and suppress deposits such as dust.

(8) Tackifiers Examples of tackifiers include aliphatic petroleum resins, alicyclic hydrogenated petroleum resins, aromatic petroleum resins, C5 petroleum resins, terpene resins, coumarone / indene resins, Known tackifiers such as phenol resins, rosin resins, tackifiers, propylene-based soft resins, hydrogenated styrene-based elastomers and the like can be mentioned. These are one or two types within a range that does not significantly impair the effects of the present invention. These can be used in combination. Specific examples of the propylene-based soft resin include the “Versify” series manufactured by Dow Chemical Japan Co., Ltd., the “Vistamax” series manufactured by ExxonMobil, and the “Notio” series manufactured by Mitsui Chemicals, Inc. Specific examples of the hydrogenated styrene-based elastomer include, but are not limited to, “Dynalon” series manufactured by JSR Corporation.

  The blending amount in the case of blending the tackifier is not particularly limited as long as the effects of the present invention are not impaired, but 100 weights of each resin used for each of the base layer, the tacky layer and the release treatment layer. 0.0001 to 200 parts by weight with respect to parts. Preferably it is 0.01-150 weight part, More preferably, it is 1-150 weight part, Most preferably, it is 10-100 weight part. When the compounding amount of the tackifier is within the above range, the adhesive strength is improved.

(9) Others Further, an elastomer is blended as a component for appropriately adjusting flexibility and tackiness within a range that does not significantly impair the effects of the present invention, an ultraviolet absorber, a metal deactivator, a peroxide, and a filler. Antibacterial and antifungal agents, fluorescent whitening agents, antifogging agents, flame retardants, colorants, pigments, natural oils, synthetic oils, waxes, and the like can be blended, and the blending ratio is an appropriate amount.

The blending of the above various additives can be directly added to the propylene-ethylene copolymer of the present invention obtained by polymerization and melt kneaded for use, or may be added during melt kneading. . Furthermore, it can be added directly after melt-kneading, or can be added as a masterbatch within a range that does not significantly impair the effects of the present invention. Moreover, you may add by these composite methods.
In general, additives such as antioxidants and neutralizers are blended, mixed, melted and kneaded, and then molded into products for use. It is also possible to add and use other resins or other additional components (including a masterbatch) as long as the effects of the present invention are not significantly impaired during molding.

  For the above mixing, melting, and kneading, any conventionally known method can be used. Usually, a Henschel mixer, a super mixer, a V blender, a tumbler mixer, a ribbon blender, a Banbury mixer, a kneader blender, a uniaxial or biaxial kneading. It can be carried out in an extruder. Among these, it is preferable to perform mixing or melt-kneading with a uniaxial or biaxial kneading extruder.

5). Production of surface protective film The surface protective film of the present invention can be produced by a known method for producing a laminated film.
For example, it manufactures by well-known techniques, such as a T die-cast method, a water cooling inflation method, an air cooling inflation method.
In the T-die casting method, a resin melt-kneaded by an extruder is extruded from the T-die and cooled by being brought into contact with a roll through which a coolant such as water is passed, and generally has good transparency and good thickness accuracy. A film can be produced. Such a method is a preferable manufacturing method for the film.

  Here, the thickness of the surface protective film is not particularly limited, but is preferably 10 to 500 μm, more preferably 20 to 200 μm, still more preferably 30 to 100 μm, and most preferably 40 to 80 μm. If the thickness is outside this range, processing becomes difficult.

As a means for providing the adhesive layer on one side of the base material layer, as a method obtained by application by a solution coating method or the like, an adhesive dissolved in an organic solvent such as a toluene solution is applied to one side of the base material layer by a roll coater or the like. Thereafter, a method of forming an adhesive layer by drying can be mentioned. At that time, in order to improve the affinity between the base material layer and the pressure-sensitive adhesive layer, conventionally known corona discharge treatment, plasma discharge treatment, primer treatment, etc. are performed on one surface of the base material layer (adhesion surface with the pressure-sensitive adhesive layer). May be.
In addition, as a method for obtaining the adhesive layer by lamination, the adhesive is heated and melted by an extruder, extruded into a film form from a T die, and laminated on one side of the substrate layer, or the substrate layer is obtained by an extruder. And a method in which the pressure-sensitive adhesive is heated and melted and coextruded into a film shape from a T-die together with the base material layer.
In the present invention, adopting a method in which the adhesive layer is coextruded with the base material layer in the form of a film from a T-die is advantageous in terms of contamination problems and economical points.

  The thickness of the adhesive layer is not particularly limited because the adhesive strength varies depending on the application, but in the case of a method of forming an adhesive layer by applying an adhesive in a later step, the adhesive layer is heated and melted from an extruder. Also in the method of forming a layer, it is 0.1-100 micrometers normally, Preferably it is 1-50 micrometers, More preferably, it is 5-30 micrometers, Most preferably, it is 10-20 micrometers.

Examples of means for forming the release treatment layer provided on the other surface of the adhesive layer of the surface protective film of the present invention include known methods such as coating, curing, and lamination.
As a method for obtaining a release treatment layer by coating, a release treatment agent dissolved in an organic solvent such as a toluene solution is applied to one side of the base material layer with a roll coater, and then dried to cure the release treatment agent and release. The method of forming a process layer can be mentioned. At that time, in order to improve the affinity between the base material layer and the release treatment layer, conventionally known corona discharge treatment, plasma discharge treatment, primer treatment, etc. are performed on one side of the base material layer (adhesion surface with the release treatment layer). May be.
Further, as a method of obtaining the release treatment layer by lamination, the release treatment layer is heated and melted by an extruder, and is laminated in a film shape from a T-die on one side of the base material layer, or by an extruder. Examples thereof include a method in which the material layer and the release treatment layer are heated and melted and coextruded into a film shape from a T die together with the base material layer.
In the present invention, adopting a method of roughening the surface of the release treatment layer to form unevenness and imparting release properties is advantageous in terms of contamination problems and economical points, and is suitable for the production of the release treatment layer. In addition, a method of co-extrusion with a T-die and lamination is preferable.

  Although the thickness of the said peeling process layer is not specifically limited, Usually, 0.1-100 micrometers, Preferably it is 1-50 micrometers, More preferably, it is 5-30 micrometers, Most preferably, it is 10-20 micrometers.

6). Applications of the surface protective film Applications of the surface protective film of the present invention include all known products that require surface protection. By field, for example, protective films for transporting electronic components and printed circuit board protection Electronics field such as film, window glass protection film, baking coating film, guard film for protecting automobiles to users, marking film for display, marking film for decoration and sponge for cushioning, protection, heat insulation and soundproofing Automotive field such as film, medical and sanitary material field such as adhesive bandages and transdermal patches, electrical insulation, identification, duct construction, window glass protection, curing, packaging, packing, office use, Residential and construction fields such as household, fixing, bundling and repair protective films can be listed.
Among these, particularly suitable for surface protection of building members such as synthetic resin plates, decorative plates, metal plates, and glass plates, and surface protection of components of liquid crystal display devices such as polarizing plates and retardation plates. Can do.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples. The physical property measurement methods, characteristic evaluation methods, and resin materials used in Examples and Comparative Examples are as follows.

1. Physical property measurement method, characteristic evaluation method (1) MFR:
The propylene-ethylene block copolymer is measured at 230 ° C. under a load of 21.18 N in accordance with JIS K7210-1995, and the ethylene / α-olefin copolymer is in accordance with JIS K6922-2: 1997 appendix. , Measured at 190 ° C. and a load of 21.18 N.

(2) Melting peak temperature:
Using a differential scanning calorimeter (DSC manufactured by Seiko Co., Ltd.), a sample amount of 5.0 mg was taken, held at 200 ° C. for 5 minutes, crystallized to 40 ° C. at a rate of temperature decrease of 10 ° C./minute, and further 10 ° C. / The melting peak temperature (Tmp) when melted at a heating rate of minutes was measured.

(3) Weight average molecular weight (Mw), number average molecular weight (Mn):
It measured by the method described by description of the base material layer and the adhesion layer.

(4) TREF measurement of base material layer resin:
A sample is dissolved in o-dichlorobenzene (containing 0.5 mg / ml BHT) at 140 ° C. to prepare a solution. This is introduced into a 140 ° C. TREF column, cooled to 100 ° C. at a rate of 8 ° C./min, subsequently cooled to −15 ° C. at a rate of 4 ° C./min, and held for 60 minutes. Thereafter, o-dichlorobenzene (containing 0.5 mg / ml BHT) as a solvent is caused to flow through the column at a flow rate of 1 ml / min, and components dissolved in o-dichlorobenzene at −15 ° C. in the TREF column. Elution is performed for 10 minutes, and then the column is linearly heated to 140 ° C. at a heating rate of 100 ° C./hour to obtain an elution curve.

(A) Apparatus (a-1) TREF part TREF column: 4.3 mmφ × 150 mm stainless steel column Column filler: 100 μm Surface inactive processing glass beads Heating method: Aluminum heat block Cooling method: Peltier element (Peltier element is cooled by water )
Temperature distribution: ± 0.5 ° C
Temperature controller: Chino Corporation Digital Program Controller KP1000 (Valve Oven)
Heating method: Air bath oven Measurement temperature: 140 ° C
Temperature distribution: ± 1 ° C
Valve: 6-way valve 4-way valve

(I-2) Sample injection part Injection method: Loop injection method Injection amount: Loop size 0.1 ml
Inlet heating method: Aluminum heat block Measurement temperature: 140 ° C
(I-3) Detection unit Detector: Fixed wavelength infrared detector MIRAN 1A manufactured by FOXBORO
Detection wavelength: 3.42 μm
High-temperature flow cell: Micro flow cell for LC-IR Optical path length 1.5mm Window shape 2φ x 4mm oval Synthetic sapphire window Measurement temperature: 140 ° C
(A-4) Pump unit Liquid feed pump: SSC-3461 pump (b) manufactured by Senshu Kagaku Co., Ltd. Measurement conditions Solvent: o-dichlorobenzene (including 0.5 mg / ml BHT)
Sample concentration: 5 mg / ml
Sample injection volume: 0.1 ml
Solvent flow rate: 1 ml / min

(5) Temperature rising elution fractionation (TREF) method of adhesive layer resin:
It was measured by the method described in the description of the adhesive layer.

(6) Solid viscoelasticity measurement:
The sample used was cut into a strip of 10 mm width × 18 mm length × 2 mm thickness from a 2 mm thick sheet injection molded under the following conditions. The apparatus used was ARES manufactured by Rheometric Scientific. The frequency is 1 Hz. The measurement temperature was raised stepwise from −60 ° C., and measurement was performed until the sample melted and became impossible to measure. The strain was performed in the range of 0.1 to 0.5%.
Test piece preparation conditions Standard number: JIS-K7152 (ISO294-1)
Molding machine: TU-15 injection molding machine manufactured by Toyo Machine Metal Co., Ltd. Molding machine set temperature: 80, 80, 160, 200, 200, 200 ° C. from below the hopper
Mold temperature: 40 ℃
Injection speed: 200 mm / sec (speed in the mold cavity)
Injection pressure: 800 kgf / cm ²
Holding pressure: 800 kgf / cm ²
Holding time: 40 seconds Mold shape: Flat plate (thickness 2 mm, width 30 mm, length 90 mm)

(7) Intrinsic viscosity (synonymous with intrinsic viscosity) of normal temperature xylene soluble component (CXS):
A 2 g sample is dissolved in 300 ml of p-xylene (containing 0.5 mg / ml BHT) at 130 ° C. to make a solution, and then left at 23 ° C. for 12 hours. Thereafter, the precipitated polymer is filtered off, p-xylene is evaporated from the filtrate, and further dried under reduced pressure at 100 ° C. for 12 hours, and CXS is collected and weighed. The intrinsic viscosity of the obtained CXS component was measured at 135 ° C. using Decalin as a solvent using an Ubbelohde viscometer.

(8) Calculation of ethylene content It measured by the method described by description of the base material layer.

(9) Tensile elastic modulus: The film was measured for tensile elastic modulus in the flow direction (MD) under the following conditions in accordance with ISO 527.
It can be said that the lower the obtained numerical value is, the more flexible the film is, and it is preferably 400 MPa or less as a flexible surface protective film, more preferably 300 MPa or less.
Sample length: 150mm
Sample width: 10mm
Distance between chucks: 100mm
Crosshead speed: 25mm / min

(10) Fisheye:
The film was cut into a size of 20 cm × 15 cm, five films were visually observed, the number of fish eyes was counted, and the number per 1 m ^{2 of} area was calculated. The size of the fish eye is 0.4 mm or more in the major axis (≧ 0.4 mm), 0.2 mm or less smaller than 0.4 mm (<0.4 mm to ≧ 0.2 mm), 0.1 mm or larger smaller than 0.2 mm (< 0.2 mm to ≧ 0.1 mm), and the number of each was divided (unit: pieces / m ² ).
When the surface of the protective film is attached to the object to be protected and stacked and stored, the object having less fish eyes is good as a film for surface protection without causing a dent in the object to be protected.

(11) Tackiness:
Acrylic resin plate (mirror surface acrylic plate (“Acrylite L001” 3 mm plate manufactured by Mitsubishi Rayon Co., Ltd.)) preliminarily heated to 60 ° C., with the vertical direction of the film taken as the longitudinal direction, 25 mm wide and 20 cm long After the pasted film was aged for 12 hours at a temperature of 23 ° C. and a humidity of 50%, the adhesive strength per 25 mm width was measured at a pulling rate of 300 mm / min and a peeling angle of 180 ° C. in accordance with JIS Z0237. Was measured.
The higher the value, the higher the adhesive strength. Although the target strength varies depending on the adherend, the adhesive strength is generally used in the range of 1 to 1000 g / 25 mm, preferably in the range of 4 to 500 g / 25 mm. If the adhesive strength is too low, bonding to the adherend cannot be performed. If the adhesive strength is too high, it cannot be easily peeled off from the adherend.

(12) Exterior (peeling treatment layer) -adhesive delamination property:
Usually, the surface protecting film is wound around a paper tube in a form in which the exterior (peeling layer) and the adhesive layer are in contact with each other, and the film is fed out and adhered to the product. As an evaluation of unwinding property, the molded film is wound up in a form in which the outer layer (peeling layer) and the adhesive layer are in contact with a 3-inch paper tube, attached to the unwinding machine, and wrinkled, sagging, etc. It was visually confirmed whether or not it could be smoothly fed out, and ○ that was able to be smoothly fed out was marked with ○, and that that could not be smoothly fed out was marked with ×.

(13) Contamination resistance of adherend:
In the evaluation of adhesiveness, when the film was peeled from the acrylic plate, the case where no peeling mark remained was marked with ○, and the case where the peeling mark or the adhesive layer resin remained on the acrylic plate was marked with x.

(14) Center plane average roughness (SRa):
Using a surface roughness profile measuring machine “Surfcom 1500DX” manufactured by Tokyo Seimitsu Co., Ltd., the measurement was performed under the conditions described above.

2. Resin Material (1) Base Layer Resin As the propylene-ethylene block copolymer of the base layer resin, the propylene-ethylene block copolymers (PEB-1 to 9) obtained in Production Examples 1 to 9 described later are used. It was.
The polymerization conditions and polymerization results are shown in Table 3, and the physical properties are shown in Table 4.

(Production Example 1)
(I) Preparation of prepolymerization catalyst (a) Chemical treatment of silicate In a 10-liter glass separable flask equipped with a stirring blade, 3.75 liters of distilled water, followed by 2.5 kg of concentrated sulfuric acid (96%) Slowly added. At 50 ° C., 1 kg of montmorillonite (Menzawa Chemical Co., Ltd. Benclay SL; average particle size = 25 μm, particle size distribution = 10-60 μm) was dispersed, heated to 90 ° C., and maintained at that temperature for 6.5 hours. After cooling to 50 ° C., the slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake to reslurry it, and then filtered. This washing operation was performed until the pH of the washing solution (filtrate) exceeded 3.5. The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 707 g.
(B) Drying of silicate The silicate previously chemically treated was dried with a kiln dryer. Specifications and drying conditions are as follows.
Rotating cylinder: Cylindrical inner diameter 50mm Heating zone 550mm (Electric furnace) Speed up with hoisting blade: 2rpm
Tilt angle: 20/520 Silicate feed rate: 2.5 g / min Gas flow rate: Nitrogen 96 liters / hour Countercurrent drying temperature: 200 ° C. (powder temperature)

(C) Preparation of catalyst An autoclave having an internal volume of 16 liters having a stirring and temperature control device was sufficiently substituted with nitrogen. 200 g of the dried silicate was introduced, 1,160 ml of mixed heptane and 840 ml of a heptane solution of triethylaluminum (0.60 M) were added and stirred at room temperature. After 1 hour, the mixture was washed with mixed heptane to prepare a silicate slurry to 2,000 ml. Next, 9.6 ml of a heptane solution of triisobutylaluminum (0.71 ML) was added to the silicate slurry prepared above and reacted at 25 ° C. for 1 hour. In parallel, 187 ml of (r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azulenyl}] zirconium and 2,180 mg (0.3 mM) of mixed heptane Then, 33.1 ml of a heptane solution of triisobutylaluminum (0.71 M) was added, and the mixture reacted at room temperature for 1 hour was added to the silicate slurry. After stirring for 1 hour, 5,000 ml was added with mixed heptane. Prepared.

(D) Prepolymerization / washing Subsequently, the temperature in the tank was raised by 40 ° C., and when the temperature was stabilized, propylene was supplied at a rate of 100 g / hour to maintain the temperature. After 4 hours, the supply of propylene was stopped and maintained for another 2 hours.
After completion of the prepolymerization, the residual monomer was purged, stirring was stopped and the mixture was allowed to stand for about 10 minutes, and then the supernatant was decanted to 2,400 ml. Subsequently, 9.5 ml of a heptane solution of triisobutylaluminum (0.71 ML) and 5600 ml of mixed heptane were further added, stirred for 30 minutes at 40 ° C., allowed to stand for 10 minutes, and then 5600 ml of the supernatant was removed. This operation was further repeated 3 times. When the component analysis of the last supernatant liquid was performed, the concentration of the organoaluminum component was 1.23 mmol / liter, the Zr concentration was 8.6 × 10 −6 g / L, and the abundance in the supernatant with respect to the charged amount was It was 0.016%. Subsequently, 170 ml of a heptane solution of triisobutylaluminum (0.71 ML) was added, followed by drying at 45 ° C. under reduced pressure. A prepolymerized catalyst containing 2.0 g of polypropylene per 1 g of catalyst was obtained.

(Ii) First Step In the first step, propylene-ethylene random copolymerization was carried out using a liquid phase polymerization vessel with an internal volume of 0.4 m ^{3 and} a stirrer. Liquefied propylene, liquefied ethylene, and triisobutylaluminum were continuously fed at 90 kg / hour, 4.2 kg / hour, and 21.2 g / hour, respectively. The hydrogen supply amount was adjusted so that the MFR in the first step became a target value.
Further, the above prepolymerized catalyst was supplied as a catalyst (excluding the weight of the prepolymerized polymer) so as to be 6.9 g / hour. The polymerization tank was cooled so that the polymerization temperature was 45 ° C.
When the propylene-ethylene random copolymer obtained in the first step was analyzed, BD (bulk density) was 0.46 g / cc, MFR was 7.0 g / 10 min, and ethylene content was 3.7% by weight. It was.

(Iii) Second Step In the second step, propylene-ethylene random copolymerization was carried out using a stirred gas phase polymerization tank having an internal volume of 0.5 m ³ . The slurry containing polymer particles was continuously extracted from the liquid phase polymerization tank in the first step, and after liquefied propylene was flushed, the pressure was increased with nitrogen and continuously supplied to the gas phase polymerization tank.
The polymerization tank was controlled so that the temperature was 80 ° C. and the total partial pressure of propylene, ethylene and hydrogen was 1.5 MPa. At that time, the concentrations of propylene, ethylene, and hydrogen in the total partial pressure of propylene, ethylene, and hydrogen were controlled to be 66.97 vol%, 32.99 vol%, and 420 vol ppm, respectively.
Furthermore, ethanol was supplied to the gas phase polymerization tank as an activity inhibitor. The supply amount of ethanol was set to 0.3 mol / mol with respect to aluminum in TIBA supplied along with the polymer particles supplied to the gas phase polymerization tank.
When the propylene-ethylene block copolymer thus obtained was analyzed, the activity was 8.7 kg / g-catalyst, the BD was 0.41 g / cc, the MFR was 7.0 g / 10 min, and the ethylene content was 8.7. % By weight.

(Iv) Granulation The following antioxidant was added to the propylene-ethylene block copolymer powder obtained above with a blender, and the mixture was sufficiently stirred and mixed.
Antioxidant: Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane (manufactured by Ciba Specialty Chemicals Co., Ltd., Irganox 1010) 0.05 Parts by weight, tris (2,4-di-t-butylphenyl) phosphite (manufactured by Ciba Specialty Chemicals Co., Ltd., Irgafos 168) 0.10 parts by weight propylene-ethylene block copolymer with added additives The powder was mixed at a high speed at 750 rpm for 1 minute at room temperature with a Henschel mixer, and then melted at a screw rotation speed of 200 rpm, a discharge rate of 10 kg / hr, and an extruder temperature of 190 ° C. in a PCM twin screw extruder having a screw diameter of 30 mm. While kneading and cooling and solidifying the molten resin extruded from the strand die in a cooling water tank Taking up and cutting the strand into a diameter of about 2 mm and a length of about 3 mm using a strand cutter, a propylene-ethylene block copolymer raw material pellet (PEB-1) was obtained.
The result of the TREF measurement of PEB-1 is shown in FIG.

(Production Examples 2 to 7)
A propylene-ethylene block copolymer was produced in the same manner as in Production Example 1 except that the polymerization conditions were changed to those shown in Table 3.
From the resulting propylene-ethylene block copolymer powder, raw material pellets (PEB-2 to 7) were obtained under the same additive formulation and granulation conditions as in Production Example 1.

(Production Example 8)
(I) Preparation of solid catalyst component 2,000 milliliters of dehydrated and deoxygenated n-heptane was introduced into a fully nitrogen-substituted flask, and then 2.6 mol of MgCl ₂ and Ti (On-C ₄ H ₉ ) 5.2 mol of ₄ was introduced and reacted at 95 ° C. for 2 hours. After completion of the reaction, the temperature was lowered to 40 ° C., and then 320 ml of methylhydropolysiloxane (20 centistokes) was introduced and reacted for 3 hours. The resulting solid component was washed with n-heptane.
Next, 4,000 milliliters of n-heptane purified in the same manner as described above was introduced into a sufficiently nitrogen-substituted flask, and 1.46 mol of the solid component synthesized above was introduced in terms of Mg atoms. Next, 25 ml of n-heptane was mixed with 2.62 mol of SiCl ₄ , introduced into the flask at 30 ° C. for 30 minutes, and reacted at 70 ° C. for 3 hours. After completion of the reaction, washing with n-heptane was performed. Next, 0.15 mol of phthalic acid chloride was mixed with 25 ml of n-heptane, introduced into the flask at 70 ° C. for 30 minutes, and reacted at 90 ° C. for 1 hour. After completion of the reaction, washing with n-heptane was performed. Next, 11.4 mol of TiCl ₄ was introduced and reacted at 110 ° C. for 3 hours. After completion of the reaction, the solid component was obtained by washing with n-heptane. The titanium content of this solid component was 2.0% by weight.
Next, the autoclave having an internal volume of 16 liters having a stirring and temperature control device was sufficiently replaced with nitrogen, and 5,000 milliliters of n-heptane purified in the same manner as above was introduced into the autoclave to synthesize the solid component synthesized above. Gram was introduced, and 0.875 mol of SiCl ₄ was introduced and reacted at 90 ° C. for 2 hours. After completion of the reaction, further (CH ₂ ═CH) Si (CH ₃ ) ₃ 0.15 mol, (t-C ₄ H ₉ ) (CH ₃ ) Si (OCH ₃ ) ₂ 0.075 mol and Al (C ₂ H ₅ ) ₃ 0.4 mol was sequentially introduced and contacted at 30 ° C. for 2 hours. After completion of the contact, it was thoroughly washed with n-heptane to obtain a solid catalyst component mainly composed of magnesium chloride. The titanium content of this product was 1.8% by weight.

(Ii) Prepolymerization An autoclave having an internal volume of 16 liters equipped with a stirring and temperature control device was sufficiently replaced with nitrogen. To this, 100 g of the n-heptane slurry of the solid catalyst component prepared above was introduced as a solid catalyst component, and n-heptane was further introduced to adjust the liquid level to 5,000 ml. Next, the temperature in the tank was adjusted to 15 ° C., and 0.1 mol of triethylaluminum / n-heptane solution (10 wt%) was added as Al (C ₂ H ₅ ) ₃ . Thereafter, prepolymerization was performed by supplying propylene at a rate of 50 g / hour for 2 hours. After completion of the prepolymerization, the residual monomer was purged and the solid catalyst was thoroughly washed with n-heptane. After the washing, drying under reduced pressure was performed to obtain a prepolymerized catalyst. The prepolymerized catalyst contained 2.0 g of polypropylene per 1 g of the catalyst.
(Iii) Polymerization Production Example except that the prepolymerized catalyst thus obtained was used, and triethylaluminum was continuously fed at 10 g / hour instead of triisobutylaluminum, and the polymerization conditions shown in Table 3 were used. In the same manner as in No. 1, a propylene-ethylene block copolymer was produced.
From the resulting propylene-ethylene block copolymer powder, raw material pellets (PEB-8) were obtained under the same additive formulation and granulation conditions as in Production Example 1.

(Production Example 9)
In Production Example 1, polymerization was carried out in the same manner as in Polymerization Production Example 1 except that only the first step was carried out without carrying out the second step, and a propylene-ethylene random copolymer was produced.
From the resulting propylene-ethylene random copolymer powder, raw material pellets (PEB-9) were obtained under the same additive formulation and granulation conditions as in Production Example 1.
Table 3 shows the polymerization conditions and polymerization results, and Table 4 shows the characteristics of the pellets PEB-1 to PEB-9.

(2) Adhesive layer resin As the ethylene / α-olefin copolymer of the adhesive layer resin, the ethylene / α-olefin random copolymer (PE-1 to 2) obtained in the following Production Examples 10 to 11 using a metallocene catalyst. High-pressure low-density polyethylene (manufactured by Nippon Polyethylene Co., Ltd., brand name: Novatec LD LF441B) was used.
Table 5 shows these characteristics.

(Production Example 10)
The catalyst was prepared by the method described in JP-T-7-508545. That is, to the complex dimethylsilylenebis (4,5,6,7-tetrahydroindenyl) hafnium dimethyl 2.0 mmol, tripentafluorophenyl boron was added in an equimolar amount with respect to the complex, and diluted to 10 liters with toluene. A catalyst solution was prepared.
A stirred autoclave type continuous reactor having an internal volume of 1.5 liters was maintained at a pressure of 130 MPa, and a mixture of ethylene and 1-hexene was 40 kg / hour so that the composition of 1-hexene was 64% by weight. Continuously. Further, the catalyst supply amount was adjusted so that the polymerization temperature was maintained at 150 ° C. The amount of polymer production per hour was about 3.0 kg. After completion of the reaction, an ethylene / 1-hexene copolymer (PE1) having a 1-hexene content of 15% by weight was obtained. The obtained ethylene / 1-hexene copolymer (PE1) was pelletized at an extrusion temperature of 230 ° C. using a 50 mmφ single screw extruder to obtain an adhesive resin (PE-1).

(Production Example 11)
In Production Example 10, the conditions were changed so that the polymerization temperature was 135 ° C., and the composition of 1-hexene in the mixture of ethylene and 1-hexene was 74% by weight, and an ethylene / 1-hexene copolymer (PE2 ) The obtained ethylene / 1-hexene copolymer (PE2) was pelletized at an extrusion temperature of 230 ° C. using a 50 mmφ single screw extruder to obtain an adhesive resin (PE-2).
Table 5 shows the characteristics of PE-1 and PE-2 and LF441B.

(3) Release treatment layer The following polyolefin resin was used as the release treatment layer resin.
Propylene homopolymer (homopolypropylene)
Nippon Polypro Co., Ltd., Brand Name: Novatec PP, FY4
Propylene / ethylene random copolymer Nihon Polypro Co., Ltd., Brand Name: Wintech WFW4
Propylene-ethylene block copolymer Nippon Polypro Co., Ltd., Brand Name: Novatec PP, BC3HF
Low density polyethylene Nippon Polyethylene Co., Ltd. Brand Name: Novatec LD LC600A
MFR: 7.0 g / 10 min, density: 0.918 g / cm ³ , Mw / Mn: 7.9
Low density polyethylene Nippon Polyethylene Co., Ltd., Brand Name: Novatec LD LF240
MFR: 0.7 g / 10 min, density: 0.924 g / cm ³ , Mw / Mn: 4.9
Low density polyethylene Nippon Polyethylene Co., Ltd., Brand Name: Novatec LD LF441B
MFR: 2.0 g / 10 min, density: 0.924 g / cm ³ , Mw / Mn: 4.4
High density polyethylene Nippon Polyethylene Co., Ltd., Brand Name: Novatec HD HJ560
MFR: 7 g / 10 min, density: 0.964 g / cm ³ )

Example 1
PEB-1 was used as a base material layer, PE-1 was used as an adhesive layer, and LC600A was used as a release treatment layer.
Using a multi-layer T-die molding machine having a release agent layer extruder 20 mmφ, a substrate layer extruder 35 mmφ, and an adhesive layer extruder 20 mmφ, peeling is performed at a molding temperature of 230 ° C. and a cooling roll temperature of 30 ° C. A surface protective film made of a multilayer T-die film having a treatment layer thickness of 20 μm, a base material layer thickness of 20 μm, and an adhesive layer thickness of 10 μm was prepared. Table 6 shows the evaluation results of the obtained surface protective film.

(Example 2)
Evaluation was performed by forming a film by the same method as in Example 1 except that the base layer resin PEB-1 used in Example 1 was replaced with PEB-2. The results are shown in Table 6.

(Example 3)
Evaluation was performed by forming a film in the same manner as in Example 1 except that the base layer resin PEB-1 used in Example 1 was replaced with PEB-3. The results are shown in Table 6.

Example 4
Evaluation was performed by forming a film in the same manner as in Example 1 except that the base layer resin PEB-1 used in Example 1 was replaced with PEB-4. The results are shown in Table 6.

(Example 5)
A film was formed and evaluated in the same manner as in Example 1 except that the adhesive layer resin PE-1 used in Example 1 was replaced with PE-2. The results are shown in Table 6.

(Example 6)
Except that the adhesive layer resin PE-1 used in Example 1 was changed to a pellet mixture of PE-1 (70% by weight) and PE-2 (30% by weight), a film was formed in the same manner as in Example 1 for evaluation. went. The results are shown in Table 6.

(Example 7)
Example 1 except that the adhesive layer resin PE-1 used in Example 1 was changed to a pellet mixture of PE-2 (70% by weight) and PEB-1 (30% by weight) used for the base layer resin. The film was formed by the same method and evaluated. The results are shown in Table 6.

(Example 8)
Example 1 except that the adhesive layer resin PE-1 used in Example 1 was changed to a pellet mixture of PE-2 (50% by weight) and PEB-1 (50% by weight) used for the base layer resin. The film was formed by the same method and evaluated. The results are shown in Table 6.

Example 9
A film was formed in the same manner as in Example 1 except that the adhesive layer resin PE-1 used in Example 1 was changed to a pellet mixture of PE-1 (70% by weight) and tackifier Dynalon 1320P (30% by weight). Evaluation was performed. The results are shown in Table 6.

(Example 10)
A film was formed in the same manner as in Example 1 except that the adhesive layer resin PE-1 used in Example 1 was changed to a pellet mixture of PE-1 (50% by weight) and tackifier Dynalon 1320P (50% by weight). Evaluation was performed. The results are shown in Table 6.

(Example 11)
The release treatment layer resin LC600A used in Example 1 was formed and evaluated in the same manner as in Example 1 except that the mixed composition of LC600A was changed to 80% by weight and HJ560 was changed to 20% by weight. The results are shown in Table 7.

(Example 12)
Except that the release treatment layer resin LC600A used in Example 1 was replaced with BC3HF, a film was formed in the same manner as in Example 1 and evaluated. The results are shown in Table 7.

(Example 13)
The release treatment layer resin LC600A used in Example 1 was formed and evaluated in the same manner as in Example 1 except that the mixed composition of BC3HF was changed to 60% by weight and LF240 was changed to 40% by weight. The results are shown in Table 7.

(Example 14)
The release treatment layer resin LC600A used in Example 1 was formed and evaluated in the same manner as in Example 1 except that a mixed composition of 80% by weight of BC3HF and 20% by weight of LF441B was replaced. The results are shown in Table 7.

(Example 15)
The release treatment layer resin LC600A used in Example 1 was formed and evaluated in the same manner as in Example 1 except that a mixed composition of 80% by weight of BC3HF and 20% by weight of HJ560 was replaced. The results are shown in Table 7.

(Example 16)
The release treatment layer resin LC600A used in Example 1 was formed and evaluated in the same manner as in Example 1 except that the mixed composition was 80% by weight of WFW4 and 20% by weight of LF441B. The results are shown in Table 7.

(Example 17)
The release treatment layer resin LC600A used in Example 1 was formed and evaluated in the same manner as in Example 1 except that the mixed composition was 80% by weight of FY4 and 20% by weight of LF441B. The results are shown in Table 7.

(Example 18)
The release treatment layer resin LC600A used in Example 1 was formed and evaluated in the same manner as in Example 1 except that PEB-1 was replaced with a mixed composition of 80% by weight and LF441B was replaced by 20% by weight. The results are shown in Table 7.

(Example 19)
The release treatment layer resin LC600A used in Example 1 was formed and evaluated in the same manner as in Example 1 except that the mixed composition was 80% by weight of WFW4 and 20% by weight of HJ560. The results are shown in Table 7.

(Example 20)
The exfoliation treatment layer resin LC600A used in Example 1 was melt extrusion mixed with 99.75% by weight of BC3HF and 0.25% by weight of polydimethylsiloxane SH200 (manufactured by Toray Dow Corning Co., Ltd.) as a silicone release agent. Except having replaced with the composition, it formed into the film by the same method as Example 1, and evaluated. The results are shown in Table 7.

(Comparative Example 1)
A film was formed and evaluated in the same manner as in Example 1 except that the base layer resin PEB-1 used in Example 1 was replaced with PEB-5. The results are shown in Table 8.

(Comparative Example 2)
A film was formed and evaluated in the same manner as in Example 1 except that the base layer resin PEB-1 used in Example 1 was replaced with PEB-6. The results are shown in Table 8.

(Comparative Example 3)
A film was formed and evaluated in the same manner as in Example 1 except that the base layer resin PEB-1 used in Example 1 was replaced with PEB-7. The results are shown in Table 8.

(Comparative Example 4)
A film was formed and evaluated in the same manner as in Example 1 except that the base layer resin PEB-1 used in Example 1 was replaced with PEB-8. The results are shown in Table 8.

(Comparative Example 5)
A film was formed and evaluated in the same manner as in Example 1 except that the base material layer resin PEB-1 used in Example 1 was replaced with PEB-9. The results are shown in Table 8.

(Comparative Example 6)
Evaluation was performed by forming a film in the same manner as in Example 1 except that the adhesive layer resin PE-1 used in Example 1 was replaced with LF441B. The results are shown in Table 8.

(Comparative Example 7)
Except that the release treatment layer resin LC600A used in Example 1 was replaced with WFW4, a film was formed in the same manner as in Example 1 and evaluated. The results are shown in Table 8.

(Comparative Example 8)
Except having replaced PEB-1 with peeling process layer resin LC600A used in Example 1, it formed into a film by the same method as Example 1, and evaluated. The results are shown in Table 8.

  From the results of Tables 6 to 8, the surface protective film of the present invention has no sticky component bleed, so it does not affect the adherence to the adherend, and does not affect the peelability between the outer layer and the adhesive layer. (Examples 1 to 20). On the other hand, the propylene-ethylene block copolymer in which Mw / Mn obtained by the Ziegler catalyst is outside the scope of the present invention has too many fish eyes (Comparative Example 4). On the other hand, if the MFR is higher than the range of the propylene-ethylene block copolymer of the present invention, draw resonance occurs during molding, and a film having an unstable thickness and a uniform thickness cannot be obtained (Comparative Example 2). On the other hand, if the MFR is too low, a shark skin (rough skin) is generated on the film surface, and a film having a good appearance cannot be formed (Comparative Example 3). Further, if the amount of the component (A2) is too large, bleeding due to sticky components is remarkable, so that the adherend is contaminated and the peelability between the outer layer and the adhesive layer is also affected, so that the feeding property is deteriorated (Comparative Example 1). . Moreover, the film using the propylene-ethylene random copolymer which does not contain the component (A2) for the base material layer has higher rigidity and flexibility than the film using the propylene-ethylene block copolymer of the present invention for the base material layer. Is inferior (Comparative Example 5).

In addition, by using an ethylene / α-olefin random copolymer rubber-based pressure-sensitive adhesive obtained by a metallocene catalyst for the pressure-sensitive adhesive layer, a surface protective film having excellent stain resistance to an adherend can be provided ( Examples 1 to 20). On the other hand, a film using an ethylene / α-olefin random copolymer obtained by a Ziegler catalyst for the adhesive layer is not suitable as a surface protection film because of its weak adhesiveness and poor adhesion to an adherend (Comparative Example). 6).
Moreover, even if the adhesive force is strong, the peelability between the outer layer and the pressure-sensitive adhesive layer is improved by roughening the surface of the release treatment layer, and the feeding property is improved (Examples 1 to 20). On the other hand, the film in which the surface of the release treatment layer is not rough has a poor feeding property (Comparative Examples 7 to 8).

  The surface protective film of the present invention uses a specific propylene-ethylene block copolymer as a base material layer, a specific ethylene / α-olefin copolymer as an adhesive layer, and peels off a polypropylene resin or a polyethylene resin. Because it is used for the treatment layer, there are very few unmelted fish eyes at the time of film formation, and even if the surface protection film is attached to the protected object and stored in layers, the protected object will not be dented, In addition, it is excellent in flexibility, and in addition, is excellent in stain resistance to the adherend. Furthermore, by roughening the surface of the release treatment layer as the release treatment layer, the roll-off state where both the adhesive layer and the release treatment layer are in contact with each other in a solid state peels off smoothly when the roll is unwound, and the drawability improves when used. It can be used as a surface protective film having characteristics, for surface protection of building members such as synthetic resin plates, decorative plates, metal plates, and glass plates, and surface protection of liquid crystal display components such as polarizing plates and retardation plates. It can be suitably used as a film.

Claims (8)

In the surface protective film in which the adhesive layer is formed on one surface of the base material layer and the release treatment layer is formed on the other surface, the base material layer is polymerized using a metallocene catalyst, and the following (a1) and (a2) ) And propylene-ethylene block copolymer (A), and the adhesive layer is polymerized using a metallocene catalyst and has the following characteristics (b1) to (b3): It is a layer mainly composed of a polymer (B), and is based on the center plane average roughness (SRa: JIS B 0651 (2001) of the surface of the release treatment layer. A film for surface protection, characterized in that (measured in the MD direction) is 0.2 to 1.5 μm.
(A) Propylene-ethylene block copolymer (a1) 30% to 95% by weight of propylene homopolymer or propylene-ethylene random copolymer component (A1) in the first step using the metallocene catalyst, the second step A propylene-ethylene block copolymer obtained by sequential polymerization of 70 to 5% by weight of a propylene-ethylene random copolymer component (A2) containing more ethylene than the component (A1) (a2) Melt flow rate ( MFR: 230 ° C. 2.16 kg) is 1 to 30 g / 10 minutes (B) ethylene / α-olefin copolymer (b1) Density is 0.860 to 0.915 g / cm ³
(B2) In temperature rising elution fractionation (TREF) measurement using orthodichlorobenzene as a solvent, the elution amount at 20 ° C. or less is 60% by weight or less. (B3) Ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / Mn) is 3.5 or less The film for surface protection according to claim 1, wherein the propylene-ethylene block copolymer (A) further satisfies the following property (a3).
(A3) The component amount W having a molecular weight of 5,000 or less obtained by gel permeation chromatography (GPC) is 0.8% by weight or less of the total. The film for surface protection according to claim 1 or 2, wherein the propylene-ethylene block copolymer (A) satisfies the following properties (a4) to (a5).
(A4) The component (A1) obtained in the first step is a propylene-ethylene random copolymer having an ethylene content of 0.5 to 6% by weight, and the proportion in the entire propylene-ethylene block copolymer is 30 to 85%. %, And the component (A2) obtained in the second step has an ethylene content of 6 to 20% by weight more than (A1), and the proportion in the total propylene-ethylene block copolymer is 70 to 15 (A5) Plot of elution amount (dWt% / dT) against temperature by temperature rising elution fractionation method (TREF) in the temperature range of −15 ° C. to + 140 ° C. using o-dichlorobenzene solvent In the TREF elution curve obtained as
The peak temperature T (A1) observed on the high temperature side is in the range of 55 to 96 ° C.,
The peak temperature T (A2) observed on the low temperature side is 45 ° C. or lower, or the peak temperature T (A2) is not observed,
The temperature T (A4) at which 99% by weight of the propylene-ethylene block copolymer elutes is 98 ° C. or lower. The film for surface protection according to any one of claims 1 to 3, wherein the propylene-ethylene block copolymer (A) satisfies the following properties (a6) to (a7).
(A6) The component (A1) obtained in the first step is a propylene-ethylene random copolymer having an ethylene content of 1.5 to 6% by weight, and the proportion of the entire propylene-ethylene block copolymer is 30 to 70. The component (A2) in the range of wt% and obtained in the second step has an ethylene content of 8 to 15 wt% more than (A1), and the proportion in the total propylene-ethylene block copolymer is 70 to (A7) The amount of elution (dWt% / dT) with respect to the temperature by the temperature rising elution fractionation method (TREF) in the temperature range of −15 ° C. to + 140 ° C. using an o-dichlorobenzene solvent. In the TREF elution curve obtained as a plot:
The peak temperature T (A1) observed on the high temperature side is in the range of 60 to 88 ° C.,
The peak temperature T (A2) observed on the low temperature side is 40 ° C. or lower, or the peak temperature T (A2) is not observed,
The temperature T (A4) at which 99% by weight of the propylene-ethylene block copolymer elutes is 90 ° C. or lower. The film for surface protection according to any one of claims 1 to 4, wherein the propylene-ethylene block copolymer (A) further satisfies the following property (a8).
(A8) Intrinsic viscosity [η] cxs measured in a 135 ° C. decalin for 23 ° C. xylene solubles is 1 to 2 dl / g The film for surface protection according to any one of claims 1 to 5, wherein the propylene-ethylene block copolymer (A) further satisfies the following property (a9).
(A9) In the temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA), the tan δ curve has a single peak at 0 ° C. or lower.   It is used for the surface protection of a building member, The film for surface protection of any one of Claims 1-6 characterized by the above-mentioned.   It is used for the surface protection of a liquid crystal display device structural member, The film for surface protection of any one of Claims 1-6 characterized by the above-mentioned.

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