JPWO2018110361A1 - Release film and protective film - Google Patents

Abstract

Disclosed are a release film having excellent heat resistance, appearance, mechanical properties, followability, stain resistance, and release properties, and a protective film having a release layer having such properties. A release film having at least one release layer, wherein the release layer has the following characteristics (A) and (B). (A) 60% by weight or more of at least one polyolefin resin selected from polyethylene, polypropylene, and polybutene is contained. (B) 0.1 to 40% by weight of ultrahigh molecular weight polyethylene having an intrinsic viscosity [η] of 8 dl / g or more. Furthermore, the protective film which has an adhesion layer in the outermost layer with respect to the said mold release layer.

Description

  The present invention relates to a release film and a protective film having a release film. The release film of the present invention is not only an adhesive material, an adhesive film, and a release film for sheets, but also has excellent heat resistance, appearance, mechanical properties, followability, stain resistance, and release properties. It is suitably used as a release film that requires heat resistance, such as a film, a release film for flexible printed circuit boards, and a release film for prepreg molding. Furthermore, by providing an adhesive layer as the outermost layer, it can be suitably used as a protective film having excellent roll-out properties, heat resistance, contamination resistance, and appearance.

  Release films are widely used as process films for improving the handleability of adhesive materials and adhesive films and for producing various molded products. Particularly, a release film having heat resistance has high utility value as a process film in a heating process such as a printed circuit board manufacturing process, a prepreg molding process, an in-mold label process, and the like.

  For example, in the manufacturing process of a printed board, a flexible printed board, etc., a release film is used to prevent adhesion between the coverlay film and the press hot plate.

As a release film, a polyester film coated with a silicone release material, a fluorine resin film, an unstretched polyester film, an alicyclic polyolefin film, a polymethylpentene film, and the like have been proposed. (Patent Documents 1 to 4)
However, in these films, the followability to a printed circuit board or a molded body is insufficient, the releasability after press processing at a high temperature is insufficient, or a defect occurs due to a transition to a molded product. There was a thing.

  A film having an adhesive material on one outer layer is widely used as a protective film for optical members and building materials. When the protective film having a relatively high adhesive strength is in a roll state, the adhesive layer and the layer opposite to the adhesive layer are in close contact with each other. If the feeding property from the roll is inferior, an excessive load may be applied to the feeding device, the film may be deformed, or the appearance may be affected. When used as a protective film for an optical member, deformation or poor appearance of the film leads to poor quality of the adherend.

  In order to solve such problems, Patent Document 5 proposes a film having a release layer composed of an α-olefin (co) polymer having 4 or more carbon atoms and an adhesive layer composed of a styrene elastomer. Yes. However, in this method, the releasability (feeding out property from the roll) may be insufficient or the film appearance may be inferior.

JP-A-2-175247 Japanese Patent Laid-Open No. 5-283862 JP 2006-321114 A JP-A-2-175247 Japanese Patent No. 6056378

  The object of the present invention is to solve the above problems, heat release, appearance, mechanical properties, followability, stain resistance, release properties from rolls and rolls excellent in release properties, heat resistance, stain resistance, appearance It is in providing the protective film which is excellent in.

  As a result of intensive research and development to solve the above problems, the present inventor has found that the object can be achieved by adopting the following configuration.

That is, the present invention has the following features.
(1) A release film having a release layer, wherein the release layer has the following (A) and (B).
(A) 60-99.9% by weight of at least one polyolefin resin selected from polyethylene, polypropylene, and polybutene
(B) Ultra high molecular weight polyethylene having an intrinsic viscosity [η] of 8 dl / g or more 0.1 to 40% by weight
(2) A release film having a release layer, wherein the release layer has the following (A), (B) and (C).
(A) 60-99.8% by weight of at least one polyolefin resin selected from polyethylene, polypropylene, and polybutene
(B) 0.1 to 39.9% by weight of ultrahigh molecular weight polyethylene having an intrinsic viscosity [η] of 8 dl / g or more (C) 0.1 to 39.9% by weight of release material
(3) The release film according to (1) or (2), wherein the ultrahigh molecular weight polyethylene forms island-like particles in the release layer, and the island-like particle diameter is 3 to 100 μm.
(4) The release force according to any one of (1) to (3), wherein the release force after the release layer and the polyimide film are heated and pressed at 180 ° C. × 4 MPa is 0.5 N / 25 mm or less. Mold film.
(5) The release film according to any one of (2) to (4), wherein the release material is hydrosilylated polyolefin.
(6) A protective film having the release layer of the release film according to any one of (1) to (5) and having an outermost layer of a multilayer film composed of at least two layers as an adhesive layer.
(7) The protective film according to (6), wherein the adhesive layer has an olefin polymer.
(8) The protective film according to (6), wherein the adhesive layer has a styrene-based elastomer.
(9) The release film according to any one of (1) to (5), which is for producing a printed board or for producing a flexible printed board.
(10) The protective film according to any one of (6) to (8), which is for an optical film.

  By adopting the constitution of the present invention, heat resistance, appearance, mechanical properties, followability, stain resistance, release properties from rolls and rolls, roll-out performance, heat resistance, stain resistance, and excellent protection It can be a film.

  The release layer of the release film of the present invention comprises (A) at least one polyolefin resin selected from polyethylene, polypropylene, and polybutene, and (B) an ultrahigh molecular weight polyethylene having an intrinsic viscosity [η] of 8 dl / g or more. Is preferred.

  Any polyethylene, polypropylene, or polybutene can be used without particular limitation as long as it exhibits the releasability described below. Examples of the polyethylene include high pressure method low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE). Examples of polypropylene include homopolypropylene, random polypropylene, and block polypropylene. Examples of polybutene include homopolybutene, butene / ethylene copolymer, butene / propylene copolymer, and the like. These polyolefin resins may be crosslinked in order to improve heat resistance and releasability. As the crosslinking method, a known crosslinking method such as electron beam crosslinking or dynamic crosslinking in the presence of a peroxide can be employed.

  As the ultra high molecular weight polyethylene, for example, particulate ultra high molecular weight polyethylene as described in JP-A-2006-206769 is suitable. The intrinsic viscosity [η] of the ultrahigh molecular weight polyethylene is 8 dl / g or more, preferably 10 dl / g or more. Further, the average particle size of the particles is preferably 3 μm to 100 μm. Preferably it is 4-50 micrometers, More preferably, it is the range of 4-20 micrometers. The average particle size can be determined by a known method for measuring the size of fine particles, such as the Cole counter method. If the average particle size of the particles is less than 3 μm, the releasability may be insufficient and may not be preferable, and if it is more than 100 μm, it may cause fish eyes, which is not preferable. The ultra high molecular weight polyethylene used in the present invention may be crosslinked in order to improve heat resistance and releasability. As the crosslinking method, a known crosslinking method such as electron beam crosslinking or dynamic crosslinking in the presence of a peroxide can be employed.

  The composition ratio of the (A) polyolefin resin and the (B) ultrahigh molecular weight polyethylene in the release layer is such that (A) is 60 to 99.9% by weight, preferably 70 to 99.8% by weight, and more preferably 80%. -99.8% by weight, (B) is 0.1-40% by weight, preferably 0.2-30% by weight, more preferably 0.2-20% by weight. When the polyolefin resin is less than 60% by weight, it is necessary to add a large amount of a known releasable resin or a release material in order to develop releasability. In general, release resins and release materials are expensive.

  In the release film of the present invention, a release material may be added to the composition comprising the polyolefin resin and ultrahigh molecular weight polyethylene for the purpose of improving the release property.

  As the release material, a known release material can be used as long as the characteristics of the release film of the present invention are exhibited. Specific examples include silicone release materials, reaction products of ethylene / vinyl alcohol copolymer and stearyl isocyanate, and hydrosilylated polyolefins. Among these, hydrosilylated polyolefin is preferable from the viewpoint of stain resistance and releasability. The hydrosilylated polyolefin can be obtained, for example, by the method described in JP 2010-37555 A, for example, by hydrosilylating a polyolefin such as polyethylene having vinyl groups at both ends or one end.

  When the release layer in the present invention is a composition comprising (A) a polyolefin resin, (B) ultrahigh molecular weight polyethylene, and (C) a release material, the proportion of each component is such that (A) is 60 to 99.8 wt. %, Preferably 70-99.6%, more preferably 80-99.6% by weight, (B) 0.1-39.9% by weight, preferably 0.2-30% by weight, more preferably 0 0.2 to 20% by weight, and (C) is 0.1 to 39.9% by weight, preferably 0.2 to 20% by weight, more preferably 0.2 to 10% by weight.

  In the release film of the present invention, it is preferable that the ultra high molecular weight polyethylene forms island-like particles in the release layer, and the island-like particle diameter is 3 to 100 μm. Preferably, 4 to 70 μm, more preferably 4 to 40 μm island-shaped particles are formed. The island-like particle diameter of ultrahigh molecular weight polyethylene can be measured by a known method such as an optical microscope, a scanning electron microscope (SEM), or a transmission electron microscope (TEM) on the surface of the release layer. If the island-like particle diameter is smaller than 3 μm, the releasability may be insufficient, and if it is larger than 100 μm, the film appearance may be poor, which is not preferable.

  The release film of the present invention preferably has a peel force of 0.5 N / 25 mm or less after the release layer and the polyimide film are heated and pressed at 180 ° C. × 4 MPa. Preferably it is 0.3 N / 25mm or less, More preferably, it is 0.1 N / 25mm or less. By having such characteristics, it can be suitably used for applications that require releasability at high temperatures, such as in the manufacturing process of printed boards, flexible printed boards, and the like.

  The release film of the present invention has at least one release layer. A base material layer can be provided as needed. Moreover, when it is set as a release layer / base material layer, it can also be used as an adhesive film by providing an adhesive layer on the side opposite to the release layer. As the base material layer, polyester, polyamide and the like can be used in addition to known polyolefins such as polyethylene and polypropylene. Preferable examples of the base material layer when the release film of the present invention is used as a release film for producing a printed circuit board include those made of polyolefin having a melt tension (MT) measured at 190 ° C. of 1 g or more. . More preferably, those comprising a polyolefin having a melt tension of 2 g or more, and more preferably 3 to 30 g are mentioned. If MT is less than 1 g, the heat resistance may be inferior, which is not preferable. Examples of polyolefins include polypropylene, polyethylene, polybutene, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / methyl acrylate copolymer, ethylene / methyl methacrylate copolymer, and ionomer resin. Can do. Preferably, polypropylene and polyethylene are exemplified.

  Examples of polypropylene include homopolypropylene, random polypropylene, block polypropylene, and a copolymer of low crystalline propylene and an α-olefin having 2 to 10 carbon atoms. The MFR (melt flow rate) (230 ° C.) of polypropylene is preferably 0.1 to 30 g / 10 minutes. Preferably it is the range of 0.2-20 g / min. When the MFR is less than 0.1 g / min, the productivity of the film may be insufficient. When the MFR exceeds 30 g / min, when used with a release film for manufacturing a printed circuit board, the resin may protrude after molding. It may occur and is not preferable. The elastic modulus of polypropylene is preferably 800 MPa or less. Preferably it is the range of 20-600 MPa. When the elastic modulus exceeds 800 MPa, when used with a release film for producing a printed circuit board, the followability to the printed circuit board may be insufficient, which is not preferable.

Examples of polyethylene include high-pressure low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE), as well as co-use of low-crystalline ethylene and α-olefins having 3 to 10 carbon atoms. A polymer is mentioned. Preferably, the MFR (190 ° C.) is 0.01-30 g / min, more preferably 0.05-20 g / min, and the density is 0.870-0.945 g / cm ³ , more preferably 0.890-0. High pressure method low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) which are 940 g / cm ³ are mentioned. If the MFR is less than 0.01 g / min, the productivity of the film may be insufficient, and if it exceeds 30 g / min, the resin may protrude after molding when used as a release film for manufacturing printed circuit boards. Is not preferable. When the density is less than 0.870 g / cm ³ , the productivity of the film may be insufficient, and when it exceeds 0.945 g / cm ³ , when used as a release film for manufacturing a printed circuit board, The followability may be insufficient, which is not preferable. As for the thickness of the release film of this invention, 5-1000 micrometers is preferable. Preferably it is 10-500 micrometers, More preferably, it is 15-300 micrometers. In the case of a multilayer film of a base material layer and a release layer, the thickness of the release layer is preferably 0.5 to 100 μm. Preferably it is 1-50 micrometers, More preferably, it is 2-30 micrometers. As for the thickness of a base material layer, 5-800 micrometers is preferable. Preferably it is 7-400 micrometers, More preferably, it is 10-300 micrometers.

  The release film of the present invention can be produced by a known method capable of producing a polyethylene or polypropylene film such as inflation molding or T-die molding. Even in the case of a multilayer film, multilayer extrusion molding, a method of dry laminating a base material layer film and a release layer prepared in advance, a method of extrusion laminating a base material layer film and a release layer, or the like can also be employed.

  The release layer and / or the base layer of the release film of the present invention are provided with an antioxidant, a weathering agent, a crystal nucleating agent, an inorganic filler, a charge for the purpose of improving moldability and the like within a range not impairing the effects of the present invention You may add the well-known additive and filler currently used for polyolefin, such as an inhibitor.

  The present invention can provide a protective film by providing an adhesive layer.

  As the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer, an olefin polymer, a styrene-based elastomer, or the like can be used in addition to the known alkyl acrylate pressure-sensitive adhesive and rubber-based hot melt pressure-sensitive adhesive. Preferred are olefin polymers and styrene elastomers.

  Examples of the olefin polymer include ethylene homopolymers such as high-density polyethylene and high-pressure low-density polyethylene, copolymers of ethylene and α-olefins having 3 to 20 carbon atoms, ethylene and vinyl esters and acrylate esters. Preferred examples thereof include propylene homopolymers, propylene / ethylene / copolymers having 4 to 20 carbon atoms, and polymers and copolymers mainly composed of α-olefins having 4 or more carbon atoms. The For example, ethylene-butene copolymer, ethylene-pentene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene -Methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, soft propylene homopolymer, propylene-ethylene copolymer, propylene-ethylene-butene copolymer, propylene-butene copolymer, propylene-4- Examples thereof include a methylpentene copolymer and a 4-methylpentene polymer.

  Examples of the styrene elastomer include styrene-butadiene copolymer (SB), styrene-butadiene-styrene copolymer (SBS), styrene-isoprene copolymer (SI), and styrene-isoprene-styrene copolymer (SIS). Copolymers of styrene and conjugated dienes and their hydrides (styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-ethylene-butylene-styrene copolymer (SEPS), etc.), styrene-isobutylene copolymer Examples thereof include a polymer (SIB) and styrene-isobutylene-styrene (SIBS).

  The olefin polymer and these styrene elastomers may be used alone or in combination of two or more. Moreover, an olefin polymer and a styrene elastomer can be used in combination for the purpose of adjusting the adhesiveness.

  It is also possible to add a tackifier to the pressure-sensitive adhesive layer for the purpose of making the pressure-sensitive adhesive force desired in the pressure-sensitive adhesive layer of the protective film of the present invention. Examples of tackifiers include commercially available resin groups such as rosin, terpene, and coumarone-indene.

  The protective film of the present invention has an adhesive layer as the outermost layer in the release film of the present invention. In this invention, a base material layer can be provided as needed. Specific examples of the layer structure include a release layer / adhesive layer and a release layer / base material layer / adhesive layer. In addition, when the adhesive force between each layer is inadequate, the adhesive layer by an adhesive agent can also be provided between each layer. As the base material layer, in addition to known polyolefins such as polyethylene and polypropylene, polyesters, polyamides and the like can also be used as described above.

  As for the thickness of the protective film of this invention, 5-1000 micrometers is preferable. Preferably it is 10-500 micrometers, More preferably, it is 15-300 micrometers. The thickness of the release layer is preferably 0.5 to 100 μm. Preferably it is 1-50 micrometers, More preferably, it is 1-30 micrometers. As for the thickness of a base material layer, 0-800 micrometers is preferable. Preferably it is 7-400 micrometers, More preferably, it is 10-300 micrometers. The thickness of the adhesive layer is preferably 0.5 to 100 μm. Preferably it is 1-50 micrometers, More preferably, it is 1-30 micrometers.

  The protective film of the present invention can be produced by a known method capable of producing a polyethylene or polypropylene film such as inflation molding or T-die molding. In the case of a multilayer film, multilayer extrusion molding, a method of dry laminating a prepared base layer film and a release film, and a method of extruding a release layer or an adhesive layer to the base layer film are also used. it can.

  Hereinafter, although the release film of this invention is demonstrated in detail based on a specific Example, this invention is not a thing limited to these Examples. In addition, it measured and evaluated by the method shown below.

(1) Peeling force with polyimide film A 15 cm × 15 cm release film and a 50 μm-thick polyimide film (“Kapton (registered trademark)” 200H manufactured by Toray DuPont Co., Ltd.) are overlaid, using a heating press machine, Contact is made at a pressure of 4 MPa and a temperature of 180 ° C. for 5 minutes. After returning to room temperature, the peel force between the release film and the polyimide film was measured with a tensile tester, and the obtained value was taken as the peel force.

(2) Average roughness of the release layer (Ra, Rz)
The release film is stored for 3 days or more after preparation in a room temperature of 23 ° C. and a humidity of 50 RH%. After that, using a surf coder “ET4000A” manufactured by Kosaka Laboratory, centerline average roughness (Ra) and ten points Average roughness (Rz) was measured.

(3) Melt tension Using a melt tension tester (orifice inner diameter 2.1 mm, L / D = 4), 190 ° C., piston lowering speed 5.5 mm / min, take-up speed at a constant acceleration of 50 m / min. The tension value at a speed at which the strand was broken and the strand was broken was defined as melt tension (MT).

(4) Island-like particle diameter The release layer was observed from the surface with an optical microscope. The island particle size was measured.

(5) Releasability with respect to flexible printed circuit board Each determination is as follows.
◯: The release film is easily peeled off from the flexible printed board after pressing.
X: The release film adheres without being released from the flexible printed circuit board after pressing.

(6) Adhesive follow-up property Each determination is as follows.
○: The adhesive is completely embedded between the wiring patterns of the substrate.
X: Adhesive is not sufficiently buried between the wiring patterns of the substrate, and bubbles remain.

(7) Protruding state Each determination is as follows.
○: The release film is not large (10 mm or more) from the size of the flexible printed circuit board.
X: The release film protrudes large (10 mm or more) from the size of the flexible printed circuit board.

(8) Peeling force between release layer / adhesive layer A 50 mm × 100 mm size film, and the release layer and the adhesive layer are bonded together with a 2 kg load roller. After leaving at 23 ° C. for 1 day, the peeling force of the release layer of the release layer was measured with a tensile tester, and the obtained value was taken as the peeling force.

(9) Unwindability from roll A film having a length of 1000 m is wound into a roll. The state (stability, appearance) at the time of feeding the film again at a speed of 5 m / min from the roll shape was evaluated as the feeding property.
<Example 1>
MFR (230 ° C., 2.16 kg load) is 8 g / 10 minutes, and the intrinsic viscosity [η] (measured in decalin at 135 ° C.) of the rubber component (referred to cold xylene solubles) is 2.8 dl / g, 97.5% by weight of block polypropylene having an amount of rubber (referred to a cold xylene soluble amount) of 13% by weight,
Intrinsic viscosity [η] is 20 dl / g, particulate ultrahigh molecular weight polyethylene having an average particle diameter of 11 μm, 1.5% by weight,
A composition comprising 1.0% by weight of hydrosilylated polyethylene obtained by hydrosilylating a terminal vinyl polyethylene having a melting point of 116 ° C. and a number average molecular weight of 730 according to the method of JP 2010-37555 A was used as a release layer.
Random polypropylene (propylene / ethylene / butene copolymer) having a melting point of 142 ° C., MFR (230 ° C., 2.16 kg load) of 6 g / 10 min and melt tension (190 ° C.) of 0.5 g is an intermediate layer (base material layer) ).
Using these, a T-die type composite film forming machine was used to obtain a two-type three-layer film composed of a release layer / intermediate layer / release layer. The total thickness of the film was 100 μm, and the thickness of each layer was release layer / intermediate layer / release layer = 10/80/10 μm.
The release layer had an Ra of 0.50 μm and an Rz of 8.7 μm. The island-like particle diameter was in the range of 9-15 μm.

It was 0.01 N / 25mm as a result of measuring the peeling force after the thermocompression bonding with 180 degreeC and 4 Mpa of the obtained mold release film and polyimide film. The peeling force after contacting with the polyimide film at high temperature was small, and there was no tear when peeling the release film, and the heat resistance and release properties were good.
The evaluation results for flexible printed circuit boards are as follows.
Releasability from flexible printed circuit board; ○
Adhesive follow-up property; ○
Overhanging state: ×.

<Example 2>
MFR (230 ° C., 2.16 kg load) is 8 g / 10 min, rubber component intrinsic viscosity [η] (measured in 135 ° C. decalin) is 2.8 dl / g, rubber amount (cold xylene soluble amount) is 137.5% by weight of block polypropylene 97.5% by weight,
1.5% by weight of particulate ultrahigh molecular weight polyethylene having an average particle diameter of 11 μm and an intrinsic viscosity [η] of 20 dl / g, and
A composition comprising 1.0% by weight of hydrosilylated polyethylene obtained by hydrosilylating a terminal vinyl polyethylene having a melting point of 116 ° C. and a number average molecular weight of 730 according to the method of JP 2010-37555 A was used as a release layer.
Low density polyethylene (EPPE CU5003 manufactured by Sumitomo Chemical Co., Ltd.) having a density of 0.928 g / cm ³ , MFR (190 ° C., 2.16 kg load) of 0.4 g / 10 min, and melt tension (190 ° C.) of 7.0 g Substrate layer).
Using these, a T-die type composite film forming machine was used to obtain a two-type three-layer film composed of a release layer / intermediate layer / release layer. The total thickness of the film was 100 μm, and the thickness of each layer was release layer / intermediate layer / release layer = 10/80/10 μm.
The release layer had an Ra of 0.51 μm and an Rz of 8.8 μm. The island-like particle diameter was in the range of 9-15 μm.

It was 0.01 N / 25mm as a result of measuring the peeling force after the thermocompression bonding with 180 degreeC and 4 Mpa of the obtained mold release film and polyimide film.
The evaluation results for flexible printed circuit boards are as follows.
Releasability from flexible printed circuit board; ○
Adhesive follow-up property; ○
Overhanging state: ○.

<Example 3>
Mold release was performed in the same manner as in Example 1 except that the intermediate layer (base material layer) was a high-density polyethylene having an MFR (190 ° C., 2.16 kg load) of 7 g / 10 min and a melt tension (190 ° C.) of 0.8 g. A film was created.
The release layer had an Ra of 0.45 μm and an Rz of 8.5 μm. The island-like particle diameter was in the range of 9-15 μm.

The peeling force between the obtained release film and the polyimide film was 0.02 N / 25 mm. The peeling force after contacting with the polyimide film at high temperature was small, and there was no tear when peeling the release film, and the heat resistance and release properties were good.
The evaluation results for flexible printed circuit boards are as follows.
Releasability from flexible printed circuit board; ○
Adhesive follow-up property; ○
Overhanging state: ×.

<Example 4>
MFR (230 ° C., 2.16 kg load) is 8 g / 10 min, rubber component intrinsic viscosity [η] (measured in 135 ° C. decalin) is 2.8 dl / g, rubber amount (cold xylene soluble amount) is 13% by weight of block polypropylene 98.5% by weight,
1.5% by weight of an electron beam irradiated material of particulate ultrahigh molecular weight polyethylene having an intrinsic viscosity [η] of 20 dl / g and an average particle diameter of 11 μm
A release film was prepared in the same manner as in Example 1 except that the composition consisting of was used as a release layer.
The release layer had an Ra of 0.47 μm and an Rz of 8.8 μm. The island-like particle diameter was in the range of 9-15 μm.

The peeling force between the obtained release film and the polyimide film was 0.10 N / 25 mm. The peeling force after contacting with the polyimide film at high temperature was small, and there was no tear when peeling the release film, and the heat resistance and release properties were good.
The evaluation results for flexible printed circuit boards are as follows.
Releasability from flexible printed circuit board; ○
Adhesive follow-up property; ○
Overhanging state: ×.

<Comparative Example 1>
MFR (230 ° C., 2.16 kg load) is 4 g / 10 min, rubber component intrinsic viscosity [η] (measured in 135 ° C. decalin) is 2.5 dl / g, rubber amount (cold xylene soluble amount) is A release film was prepared in the same manner as in Example 1 except that 100% by weight of 13% by weight of block polypropylene was used as the release layer. The release layer had an Ra of 0.2 μm and an Rz of 3.0 μm.
No island-like particle diameter derived from ultrahigh molecular weight polyethylene was observed.

The peel strength of the obtained release film from the polyimide film was 2.1 N / 25 mm. The peeling force after contacting with the polyimide film at high temperature was large, and deformation occurred when peeling the release film, resulting in insufficient heat resistance and release properties.
The evaluation results for flexible printed circuit boards are as follows.
Releasability from flexible printed circuit board; ×
Adhesive follow-up property; ○
Overhanging state: ×.

<Example 5>
MFR (230 ° C., 2.16 kg load) is 8 g / 10 min, rubber component intrinsic viscosity [η] (measured in 135 ° C. decalin) is 2.8 dl / g, rubber amount (cold xylene soluble amount) is 137.5% by weight of block polypropylene 97.5% by weight,
Intrinsic viscosity [η] is 20 dl / g, an average particle diameter of 11 μm in the form of particulate ultrahigh molecular weight polyethylene, 1.5% by weight, and
A composition comprising 1.0% by weight of hydrosilylated polyethylene obtained by hydrosilylating a terminal vinyl polyethylene having a melting point of 116 ° C. and a number average molecular weight of 730 according to the method of JP 2010-37555 A was used as a release layer.
Random polypropylene (propylene / ethylene / butene copolymer) having a melting point of 142 ° C. and MFR (230 ° C., 2.16 kg load) of 6 g / 10 min was used as an intermediate layer (base material layer).
A composition comprising 40% by weight of a styrene-ethylene-butylene copolymer (Dynalon 1321P manufactured by JSR), 10% by weight of a terpene phenol tackifier (TH130 manufactured by Yasuhara Chemical), and 50% of high-pressure polyethylene was used as an adhesive layer.
Using these, a T-die type composite film forming machine was used to obtain a three-layer three-layer film composed of a release layer / intermediate layer / adhesive layer. The total thickness of the film was 40 μm, and the thickness of each layer was the release layer / intermediate layer / adhesive layer = 3/32/5 μm.
The release layer had an Ra of 0.50 μm, an Rz of 8.7 μm, and an island-shaped particle size of 9 to 15 μm.

  The peeling force between the release layer and the adhesive layer was 0.1 g / 25 mm. Good feeding stability from roll. The film appearance after feeding was also good.

<Comparative example 2>
MFR (230 ° C., 2.16 kg load) is 4 g / 10 min, rubber component intrinsic viscosity [η] (measured in 135 ° C. decalin) is 2.5 dl / g, rubber amount (cold xylene soluble amount) is A protective film was prepared in the same manner as in Example 5 except that 100% by weight of 13% by weight of block polypropylene was used as a release layer. The release layer had an Ra of 0.2 μm, an Rz of 3.0 μm, and no island-like particle diameter derived from ultra high molecular weight polyethylene.

  The peeling force between the release layer and the adhesive layer was 15 g / 25 mm. The feeding from the roll was irregular and unstable, and streaks (stop marks) were observed in the direction perpendicular to the feeding direction in the film after feeding.

<Example 6>
MFR (230 ° C., 2.16 kg load) is 8 g / 10 min, rubber component intrinsic viscosity [η] (measured in 135 ° C. decalin) is 2.8 dl / g, rubber amount (cold xylene soluble amount) is 13 wt% block polypropylene 98.5 wt%, and
A protective film was prepared in the same manner as in Example 5 except that a composition comprising 1.5% by weight of particulate ultrahigh molecular weight polyethylene having an intrinsic viscosity [η] of 20 dl / g and an average particle diameter of 11 μm was used as a release layer. did. The release layer had an Ra of 0.47 μm, an Rz of 8.8 μm, and an island-shaped particle size of 9 to 15 μm.

The peeling force between the release layer and the adhesive layer was 2 g / 25 mm. Good feeding from roll.
The film appearance after feeding was also good.

<Example 7>
Example 5 except that a composition comprising 90% by weight of a styrene-isobutylene-styrene copolymer (Shibustar 062M manufactured by Kaneka Corporation) and 10% by weight of a styrene-based tackifier (FTR6125 manufactured by Mitsui Chemicals) was used as the adhesive layer. A protective film was prepared in the same manner. The release layer had an Ra of 0.51 μm and an Rz of 8.5 μm.

  The peeling force between the release layer and the adhesive layer was 10 g / 25 mm. Good feeding stability from roll. The film appearance after feeding was also good.

<Comparative Example 3>
MFR (230 ° C., 2.16 kg load) is 4 g / 10 min, rubber component intrinsic viscosity [η] (measured in 135 ° C. decalin) is 2.5 dl / g, rubber amount (cold xylene soluble amount) is A protective film was prepared in the same manner as in Example 5 except that 100% by weight of 13% by weight of block polypropylene was used as a release layer. The release layer had an Ra of 0.2 μm and an Rz of 3.0 μm.

The peeling force between the release layer and the adhesive layer was 80 g / 25 mm. The feeding from the roll was irregular and unstable, and streaks (stop marks) were observed in the direction perpendicular to the feeding direction in the film after feeding.

<Example 8>
Example 5 except that a composition comprising 90% by weight of a styrene-isobutylene-styrene copolymer (Shibustar 062M manufactured by Kaneka Corporation) and 10% by weight of a styrene-based tackifier (FTR6125 manufactured by Mitsui Chemicals) was used as the adhesive layer. A protective film was prepared in the same manner. The release layer had an Ra of 0.51 μm and an Rz of 8.5 μm.

  The peeling force between the release layer and the adhesive layer was 10 g / 25 mm. The feeding stability from the roll was good, and the film appearance after feeding was also good.

<Example 9>
A protective film was prepared in the same manner as in Example 5 except that 100% by weight of propylene-ethylene-butene copolymer (Tafmer PN-2060 manufactured by Mitsui Chemicals, Inc.) was used as the adhesive layer. The release layer had an Ra of 0.51 μm and an Rz of 8.6 μm.

  The peeling force between the release layer and the adhesive layer was 3 g / 25 mm. The feeding stability from the roll was good, and the film appearance after feeding was also good.

Claims (10)

A release film having a release layer, wherein the release layer has the following (A) and (B).
(A) 60-99.9% by weight of at least one polyolefin resin selected from polyethylene, polypropylene, and polybutene
(B) Ultra high molecular weight polyethylene having an intrinsic viscosity [η] of 8 dl / g or more 0.1 to 40% by weight A release film having a release layer, wherein the release layer has the following (A), (B) and (C).
(A) 60-99.8% by weight of at least one polyolefin resin selected from polyethylene, polypropylene, and polybutene
(B) 0.1 to 39.9% by weight of ultrahigh molecular weight polyethylene having an intrinsic viscosity [η] of 8 dl / g or more (C) 0.1 to 39.9% by weight of release material The release film according to claim 1 or 2, wherein the ultrahigh molecular weight polyethylene forms island-like particles in the release layer, and the island-like particle diameter of the island-like particles is 3 to 100 µm. The release film according to any one of claims 1 to 3, wherein the release force after the release layer and the polyimide film are heated and pressurized contacted at 180 ° C x 4 MPa is 0.5 N / 25 mm or less. The release film according to any one of claims 2 to 4, wherein the release material is hydrosilylated polyolefin. The protective film which has a release layer of the release film in any one of Claims 1-5, and the outermost layer of the multilayer film which consists of at least 2 layers is an adhesion layer. The protective film according to claim 6, wherein the adhesive layer has an olefin polymer. The protective film according to claim 6, wherein the adhesive layer has a styrene-based elastomer. The release film according to any one of claims 1 to 5, which is used for manufacturing a printed circuit board or for manufacturing a flexible printed circuit board. It is an object for optical films, The protective film in any one of Claims 6-8.