KR101781230B1 - Adhesive film - Google Patents

Abstract

The present invention relates to a polypropylene type resin film comprising a laminate comprising an adhesive layer laminated on one side of a substrate layer comprising a polypropylene resin and a release layer laminated on the opposite side, Wherein the surface roughness SRa is not less than 0.050 탆 and not more than 0.200 탆 and the average surface roughness SRa of the surface of the top adhesive layer is not more than 0.030 탆 and the contact area with an adherend defined in the specification is not less than 90% and not more than 100% An amount of water and an amount of bleeding water of an antioxidant are set within a specific range. INDUSTRIAL APPLICABILITY The pressure-sensitive adhesive film of the present invention is excellent in transparency and is excellent in the appearance of an adherend after being adhered to an adherend even after being treated at a high temperature even after the pressure-sensitive adhesive film is stored in a roll state, The change of adhesive force is small.

Description

Adhesive Film {ADHESIVE FILM}

The present invention relates to an adhesive film. The adhesive film of the present invention is applied to the surface of an article such as a synthetic resin plate, a fancy plywood, a metal plate, and a coated steel plate to protect the surface of the article from the surface protection film for protecting the article from undesirable effects such as adhesion of dirt and scratch And can be particularly preferably used as a surface protective film at the time of solder dipping of a printed board. The term "adhesive film" in the present invention also means an adhesive sheet or adhesive tape.

Background Art [0002] Conventionally, an adhesive film for the purpose of protecting the surface of a cover is used for processing, storage, and transport of building materials, electric appliances, electronic products, automobiles, etc. Such adhesive films not only have good adhesiveness, Each surface should be easily detachable without contamination with an adhesive. Recently, an adhesive film based on a polyolefin-based resin has been used instead of an adhesive film based on a plasticized vinyl chloride resin. The adhesive film based on these polyolefin-based resins is mainly composed of EVA, low-density polyethylene Or an amorphous adhesive layer or an adhesive layer comprising an elastomer such as SIS or SEBS is formed integrally with the substrate layer by co-extrusion. However, the above-mentioned adhesive film tends to be affected by the environment in which the bonded body is placed, and particularly under a high temperature environment, causes extreme change with time. As a result, the adhesive strength is increased to make it difficult to peel off from the adherend, There was a problem.

As to the problem, a composition comprising an amorphous olefin polymer and a specific ethylene polymer has been disclosed as a pressure-sensitive adhesive which maintains an appropriate tackiness without undergoing extreme change over time under a low-temperature environment but a high-temperature environment regardless of the temperature range of use (See, for example, Patent Documents 1, 2, 3, etc.).

However, even in the above-mentioned adhesive film, there is a problem that blocking is caused by storage.

Also disclosed is a film in which a surface layer having a specific surface roughness is provided on the opposite side of the adhesive layer to improve blocking resistance (see, for example, Patent Documents 4, 5 and 6).

However, this film was not sufficient in terms of performance.

Japanese Patent Application Laid-Open No. 2006-63123 Japanese Patent Application Laid-Open No. 2006-299060 Japanese Patent Laid-Open No. 2006-257191 Japanese Patent Application Laid-Open No. 2008-68564 Japanese Patent Application Laid-Open No. 2008-162059 Japanese Patent Application Laid-Open No. 2009-143074

A problem to be solved by the present invention is to provide an adhesive film which has less blocking between the pressure-sensitive adhesive films, especially when the pressure-sensitive adhesive film is stored in a roll state, has less blocking and is excellent in processing suitability, And an adhesive film excellent in transparency and having little change in adhesive force while maintaining the appearance of an adherend.

The inventors of the present invention have made extensive studies in view of the above problems. As a result, they have found that when the adhesive films are overlapped with each other, the surface of the adhesive layer is easily affected by the opposite surface thereof, And that the bleed water from the adhesive layer relates to the adhesive behavior, and has arrived at the present invention.

That is, the present invention is a polypropylene type resin film comprising a laminate comprising an adhesive layer laminated on one side of a base layer comprising a polypropylene resin and a release layer laminated on the opposite side, Wherein the average surface roughness SRa is 0.050 탆 or more and 0.200 탆 or less and the average roughness SRa of the surface of the adhesive layer is 0.030 탆 or less and the contact area with the adherend defined in the specification is 90% or more and 100% or less, The amount of the bleeding of the polymer component on the acrylic plate and the amount of bleeding of the antioxidant by b1 were determined by the method of adhering to the acrylic plate (A2-a1) x2- (b2-b1) where a2 is the amount of the bleeding of the polymer component on the peeled adhered surface and the acrylic plate after one week at 40 DEG C and b2 is the amount of the antioxidant, This -50 mg / m ² to 50 mg / m ² , and the film haze is in the range of 1 to 40%.

According to the present invention, there is little blocking between the pressure-sensitive adhesive films, and even after the pressure-sensitive adhesive film is stored in a roll state, the pressure-sensitive adhesive tape is less likely to be foamed, Furthermore, the pressure-sensitive adhesive film having excellent transparency is not affected by the storage state, and an adhesive film with little change in adhesive force with time can be obtained.

Also, it has excellent adhesive property and excellent processability.

Also in this case, it is preferable that the pressure-sensitive adhesive layer contains a polypropylene-based elastomer.

Also in this case, it is preferable that the polypropylene-based elastomer is an amorphous polypropylene composed solely of a polypropylene-based resin, or a copolymer of polypropylene and ethylene-propylene rubber.

In this case, the average surface roughness SRa of the surface of the release layer is preferably 0.150 mu m or less.

Also in this case, the average surface roughness SRa of the surface of the adhesive layer is preferably 0.020 mu m or less.

In this case, it is preferable that the base layer, the adhesive layer and the release layer are melt-extruded and laminated from a plurality of extruders by a co-extrusion method.

In this case, a film roll made of the above-mentioned film and having a width of 450 mm or more and a length of 300 m or more is preferable.

The pressure-sensitive adhesive film according to the present invention is less likely to block the adhesion between the pressure-sensitive adhesive films, and even when the pressure-sensitive adhesive film is stored in a roll state, And further has an advantage that the change of the adhesive force is small while maintaining the appearance of the adherend.

1 is a schematic view of a measurement sample.

Hereinafter, embodiments of the pressure-sensitive adhesive film of the present invention will be described.

(Substrate layer)

The pressure-sensitive adhesive film of the present invention requires a base layer comprising a polypropylene-based resin. As the polypropylene-based resin used herein, a crystalline polypropylene, a random copolymer block copolymer of propylene and a small amount of? Heptane insoluble isotactic propylene homopolymer used in ordinary extrusion molding or the like, or propylene homopolymer of n-heptane insoluble isotactic propylene homopolymer or polypropylene containing propylene in an amount of 60% by weight or more and other? -Olefin , And the propylene homopolymer or a copolymer of propylene and another? -Olefin may be used alone or in combination.

The n-heptane insolubility means that the crystallinity of the polypropylene is used as an indicator and also shows safety. In the present invention, the n-heptane insoluble substance (n-heptane insoluble) extracted at 25 캜 for 60 minutes Is not more than 150 ppm (when the use temperature exceeds 100 캜, it is not more than 30 ppm).

Examples of the? -Olefin copolymerization component of a copolymer of propylene and other? -Olefins include? -Olefins having 2 to 8 carbon atoms such as ethylene or 1-butene, 1-pentene, 1-hexene, And C4 or more alpha-olefins such as 1-pentene are preferable.

Here, the copolymer is preferably a random or block copolymer obtained by polymerizing propylene with one or more of the? -Olefins exemplified above.

The melt flow rate (MFR) is in the range of 0.1 to 100 g / 10 min, preferably 0.5 to 20 g / 10 min, and more preferably 1.0 to 10 g / 10 min. And particularly preferably in the range of 2.0 to 7.0 g / 10 min.

Two or more kinds of copolymers of propylene and other? -Olefins may be used in combination. When a 1-butene copolymerized polypropylene copolymer is used, the stickiness of the film is reduced and the stickiness is improved, which is preferable for improving the contact area ratio.

(Adhesive layer)

As the resin used in the pressure-sensitive adhesive layer which is a requirement of the present invention, it is preferable to use an olefinic polymer in order to laminate an adhesive layer on one side of a base layer comprising a polypropylene resin, In order to prevent the residual adhesive layer from remaining on the adherend, it is preferable that the pressure-sensitive adhesive layer contains at least 50% or more of an amorphous polyolefin-based resin in order to attain the contact area ratio with the adherend, And it is preferable that this is finely dispersed.

As the method of containing the polyolefin-based elastomer, there are a method of using 1) a block copolymer in which an elastomer component is finely dispersed in an island shape by multistage polymerization, 2) a method of diluting the olefin-based elastomer resin with a crystalline olefin resin Method, and 3) a method of using both of them.

1) include, for example, "JERAS MC707" and "JERAS MC717" manufactured by Mitsubishi Chemical Corporation. An example of 2) is, for example, "Tapselen H3522A" manufactured by Sumitomo Chemical Co., Ltd.

However, it is difficult to prevent adhesion of the adherend and contamination of the adherend with heating and time lapse only by using these resins as they are. In order to prevent these adverse effects, the amount of the bleeding water derived from the high molecular weight, which is one of the requirements of the present invention, and the amount of the bleeding water of the antioxidant are peeled off within a specific range, , The amount of the bleed water of the polymer component on the acrylic plate and the amount of the bleed water of the antioxidant b1 were fixed on the acrylic plate and after 1 week at 40 ° C, the peeled adhesive surface and the polymer component (A2-a1) x2- (b2-b1) needs to be -50 mg / m ² or more and 50 mg / m ² or less when the amount of the bleeding water of the antioxidant is a2 and the amount of the antioxidant is b2.

The amount of the bleed water is a value obtained by extraction with chloroform, and unlike the adhesive residue of the so-called adhesive layer, it means the amount of the component derived from the polymer and the additive on the surface of the adhesive layer in a very small amount.

Examples of measures for keeping the amount of the bleeding water derived from the high molecular weight and the amount of the bleeding water for the antioxidant within a specific range include 1) a method in which the raw material resin is immersed in water to wash the low molecular weight component of the polymer component before the film formation, 2) A method in which the surface of the adhesive layer is subjected to corona treatment to increase the initial amount of bleeding derived from the high molecular weight, and 3) a method of adding a heat stabilizer that increases the amount of bleeding out after adhesion. However, depending on the conditions under which they are carried out, these methods may adversely affect the adhesive strength over time, so care must be taken.

As the antioxidant used in the present invention, a phenol-based antioxidant is preferable. For example, Irganox 1010 (manufactured by Ciba Specialty Chemicals), Irganox 1076 (manufactured by Ciba Specialty Chemicals Kabushiki Kaisha), Irganox 1330 (manufactured by Ciba Specialty Chemicals) , Irganox 3114 (manufactured by Ciba Specialty Chemicals Kabushiki Kaisha), Irganox 1425WL (manufactured by Ciba Specialty Chemicals Co., Ltd.), and the like. They have the property that the amount of bleed-out increases after adhesion.

The adhesive layer may have a melt flow rate (MFR) of 0.1 to 100 g / 10 min, preferably 0.5 to 20 g / 10 min, and more preferably 1.0 to 10 g / 10 min. And particularly preferably in the range of 2.0 to 7.0 g / 10 min.

The average surface roughness SRa of the adhesive layer surface of the adhesive film of the present invention should be 0.030 mu m or less. Preferably 0.025 占 퐉 or less, more preferably 0.020 占 퐉 or less, and particularly preferably 0.015 占 퐉 or less.

Here, when the average surface roughness SRa of the surface of the adhesive layer is more than 0.030 占 퐉, the contact area is reduced at the time of bonding with the adherend, which is a cause of deteriorating the adhesive strength. One of the factors that determine the adhesion is the force of pulling each other, that is, van der Waals force, on each surface where the bonded film is in contact, and this force is the source of adhesive force. The small contact area here means that the tensile force between the bonded film surface and the adherend surface is reduced, and the adhesive strength is lowered, which is not preferable.

Further, it is necessary to make the surface of the pressure-sensitive adhesive layer as flat as possible, and it can be said that it is preferable not to add the additive for forming the surface unevenness as much as possible.

On the other hand, if the average surface roughness SRa of the surface of the adhesive layer is made less than 0.010 mu m, it can be said that it is also practically difficult for the stretched film without additive.

The pressure-sensitive adhesive film of the present invention preferably has a thickness variation ratio in a transverse direction of 2.0% or more and 10.0% or less, preferably 8.0% or less, more preferably, 6.0% or less. When the variation rate of the thickness exceeds 10.0%, pressure unevenness occurs depending on the place when the adhesive film is pressed and adhered to the adherend, which causes deterioration of the adhesive strength, which is not preferable. On the other hand, it can be said that it is practically difficult to suppress the thickness variation rate to less than 2.0%.

The film of the present invention preferably has a value of 90% or more, more preferably 95% or more when the contact area with an adherend is measured by the following method in accordance with the test method of JIS-Z-0237 adhesive tape and pressure- , And particularly preferably 98% or more.

Accordingly, when the heat treatment is performed under the condition of 80 占 폚 for 24 hours, foaming is hardly caused, and the adhering or peeling of the adhered film from the acrylic plate can be suppressed.

By increasing the contact area, it is considered that bubbles which are invisible to the eyes existing at the interface between the adherend and the film are removed.

At this time, the difference between the initial adhesion at 50 ° C and the initial adhesion at 23 ° C is preferably 10 cN / 25 mm or less, more preferably 5 cN / 25 mm or less, When the change is smaller than that at room temperature, a change in the adhesive force with time is small.

The adhesive force of the adhesive film of the present invention is preferably in the range of 3 to 50 cN / 25 cm at 23 DEG C from the viewpoint of the protective performance and peelability of the adherend. The adhesive force can be achieved by appropriately setting the adhesive force by controlling the amount and composition of the amorphous component of the resin of the adhesive layer.

The pressure-sensitive adhesive film of the present invention can contain known additives insofar as the effect of the present invention is not impaired. For example, a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, an anti-light agent, and an impact resistance improver.

However, it is preferable that the low molecular weight substance on the surface of the adhesive layer is less than 1 mg / m ² .

(Releasing layer)

In the adhesive film of the present invention, the release layer is formed on the opposite side of the adhesive layer laminated on one side of the substrate layer. Thus, even when the adhesive films are overlapped with each other, blocking between the adhesive films is small, Even after the process is completed, there is less blocking and excellent processability.

In this case, the average surface roughness SRa of the surface is preferably 0.050 mu m or more.

However, merely by providing the releasing layer, the surface irregularities of the releasing layer are transferred to the surface of the pressure-sensitive adhesive layer to deteriorate the adhesive force and the above-mentioned adhesive area, or to cause a change in the adhesive force immediately after bonding to the adherend, Therefore, it is preferable to set the average surface roughness SRa to 0.200 mu m or less. By doing so, the blocking resistance and the protection performance of the adherend can be improved.

At this time, the surface irregularities of the release layer preferably have an average surface roughness SRa of 0.150 mu m or less on the surface, more preferably 0.060 mu m or more and 0.130 mu m or less, and most preferably 0.080 mu m or more and 0.130 mu m or less.

In order to form the surface irregularities as described above, for example, a layer containing a silicone resin or a fluorine resin, or a layer obtained by mixing a resin containing a propylene ethylene block copolymer and a polyethylene resin, can do.

As a preferable resin for obtaining the surface of the matte layer, a propylene-ethylene block copolymer such as "BC3HF" manufactured by Nippon Polypropylene Co., Ltd. can be exemplified.

The 100% propylene-ethylene block copolymer formulation is advantageous in that the average roughness SRa of the surface is increased, but when used alone, the surface roughness becomes too large. Therefore, it is necessary to dilute the polypropylene homopolymer or the propylene-ethylene random copolymer to fall within the range of the surface roughness described above.

(Adhesive film)

The haze value of the pressure-sensitive adhesive film of the present invention is preferably in the range of 1 to 40, particularly when it is used in an adherend for optical use. More preferably 1 to 30%, and particularly preferably 1 to 25%.

The thickness of the pressure-sensitive adhesive layer of the present invention is preferably 1 mu m or more and less than 30 mu m.

If the thickness of the adhesive film is less than 1 m, there is a problem of adhesion. If the thickness is 30 m or more, there is a problem that the adhesive strength of the surface of the adhesive layer is too strong.

In this case, when the adhesive force is increased, it is preferable to increase the thickness in consideration of the viscosity thereof. When the thickness of the adhesive layer is large, it is easy to increase the contact area with the adherend, and it is particularly effective when a hard resin is used for the adhesive layer.

The thickness of the adhesive layer is preferably 2 mu m or more and 20 mu m or less on the blocking surface, more preferably 2 mu m or more and 15 mu m or less, and particularly preferably 2 mu m or more and 5 mu m or less.

The thickness of the base layer of the present invention is preferably not less than 5 mu m and less than 100 mu m, and more preferably not less than 15 mu m and not more than 25 mu m.

If the thickness of the pressure-sensitive adhesive film is less than 5 占 퐉, there is a problem that the stickiness becomes weak and wrinkles are not obtained or the adhesive force is not sufficiently obtained.

Tackiness means instantaneous adhesive strength and is an index of ease of adhesion at the initial bonding time.

The adhesive film of the present invention is preferably handled in the form of a roll.

Although the upper limit of the width and the winding length of the film roll is not particularly limited, the width is preferably 1.5 m or less, and the winding length is preferably 6000 m or less when the film thickness is 45 m due to ease of handling. As the winding core, plastic cores or metal cores, typically 3 inches, 6 inches, 8 inches, etc., can be used.

Further, it is preferable that the film roll is a film roll having a length of 300 m or more and a width of 450 mm or more from the viewpoint of processability.

The pressure-sensitive adhesive film of the present invention can be applied to a variety of applications such as, for example, synthetic resin plates (for optical members, for building materials), stainless steel plates (for building materials, for example), aluminum plates, fancy plywood, In order to protect the precision machinery and the surface of the automobile body at the time of manufacture and to prevent the occurrence of scratches when the articles are stacked, stored, transported, or transported in the manufacturing process, For example, bending or pressing), it is possible to preferably use it to prevent occurrence of scratches.

[Example]

Next, the present invention will be described again with reference to examples. However, the present invention is not limited to the following examples unless they depart from the gist of the present invention. In the following Examples and Comparative Examples, evaluation methods of physical properties are as follows.

(1) Crystallization heat of fusion and crystallization heat

About 5 mg of the polyolefin resin was weighed and the temperature was raised to 200 ° C at a heating rate of 10 ° C / min using a differential scanning calorimeter (DSC-60) manufactured by Shimadzu Seisakusho Co., Ltd., and maintained at 200 ° C for 5 minutes After cooling to 0 deg. C at a cooling rate of 10 deg. C / min, the crystal heat of fusion and the crystallization heat of crystallization were obtained from a chart obtained by raising the temperature to 10 deg. C / min to 200 deg.

(2) Elastic modulus of resin

It was measured according to JIS K 7162 test method under the following conditions.

Specimen: Type 1A

Chuck spacing: 115 mm

Speed: 1 mm / min

(3) Measurement of surface roughness

Using the contact type three-dimensional center surface surface roughness meter (Model ET-30HK) and the three-dimensional roughness analyzer (SPA-11) manufactured by Kosaka Kagenkusho Co., the center surface average roughness SRa ) Was measured by a touch method under the following conditions.

Conditions were as follows, and the average value of 20 measurements was taken.

Pen tip radius: 0.5 ㎛

Pressure: 20 mg

Cutoff value: 80 탆

Measurement length: 1000 탆

Vertical magnification: 5000 times

Measuring speed: 100 탆 / s

Measurement interval: 2 ㎛

(4) Evaluation of stickiness

JIS-Z-0237 (2000) Measured by the following method in accordance with the test method of the adhesive tape and pressure-sensitive adhesive sheet.

A 50 mm x 150 mm acrylic plate (3 mm in thickness, acrylite manufactured by Mitsubishi Rayon Co., Ltd.) was prepared as an adherend, and test specimens of 25 mm in the take-up direction and 180 mm in the direction orthogonal thereto And a rubber roll having a mass of 2000 g (having a spring hardness of 80 Hs on the roller surface and a rubber layer of 6 mm in thickness, having a width of 45 mm and a diameter of 95 mm (including a rubber layer) And the test piece were reciprocated once at a speed of 5 mm / sec. After the compression, the sample was allowed to stand for 30 minutes in an environment of a temperature of 23 DEG C and a relative humidity of 65%, and the sample was allowed to stand for 24 hours and the time course was measured using "Tensilon" (UTM-IIIL) , And a resistance value when the film was peeled 180 degrees at a rate of 300 mm / min was regarded as an adhesive force [cN / 25 mm]. 180 degree peeling means that the peeling angle between the acrylic plate and the film is maintained at 180 degrees when the resistance value at the time of peeling is measured.

At the time of measurement, a polyester sheet having a thickness of 190 탆 and a size of 25 mm × 170 mm was prepared as a chuck margin of the test sample, and a margin of 15 mm was attached to the end of the test sample on which the adhesive film and the acrylic plate were pressed, And attached with a cellophane tape to give a chucking margin at the time of measurement. A schematic diagram of the measurement sample is shown in Fig. The measurement was carried out three times for one sample, and the average value thereof was regarded as the adhesion of the sample.

(5) Evaluation of the contact area ratio with the adherend

The adhesive film was adhered to the acrylic plate in the same manner as in (4), and the state of the contact surface between the acrylic plate and the adhesive film was observed at 23 占 폚 for 30 minutes.

Observation conditions: A digital image was photographed at a magnification of 100 times using a digital microscope VHX-200F manufactured by KEYENCE, and then the area ratio of the portion contacting the acrylic plate was calculated with image analysis software.

(6) Quantitative measurement of amount a1 of the bleed water of the polymer component and amount b1 of the bleed water of the antioxidant

(4), peeled off after 24 hours at 23 占 폚, and the surface of the adhesive layer of two films was opposed, and the area of 25.2 cm 占 12.4 cm could be extracted per sheet The spacer was inserted and fixed to the frame. 20 ml of chloroform was injected between the extraction surfaces and the surface bleed was extracted for 3 minutes. After recovering the extract, 10 ml of fresh chloroform was added thereto and washed gently.

On the other hand, the dried Kim Wipes previously washed with chloroform were wiped with n-hexane to wipe off the acrylic plate, and the Kim Wipes were extracted with n-hexane (wiped and extracted three times repeatedly). These extracts were collected and dried, and the weight of the residue was measured. Further, the residue was dissolved in deuterated chloroform, and a 1 H-NMR spectrum was measured using a 400 MHz-NMR apparatus manufactured by Varian. The weight ratio of each component contained in the extract was calculated from the peak area of each component of the 1 H-NMR spectrum. The weight ratio of the sum of the polymer components and the total weight of the antioxidants was multiplied by the weight of the total extract, respectively, and the amount a1 of the bleed and the amount b1 of the bleed of the antioxidant were calculated.

(7) Method for quantifying the amount a2 of the bleed water of the polymer component and the amount b2 of the bleed water of the antioxidant

(4), peeled off after one week at 40 占 폚, and then peeled off and measured in the same manner as in (6).

(8) Pollution of adherend during high temperature treatment

(4), an adhesive film was adhered to an acrylic plate, and then heat treatment was performed under conditions of 80 DEG C x 24 hours. After the bonded film was peeled off from the acrylic plate, the surface contamination of the acrylic plate was visually evaluated.

○: No pollution

△: Some contamination is seen

X: Apparently white

(9) Film Hayes

Measurement was made using a haze meter NDH-2000 manufactured by Nippon Denshoku Kogyo Co., Ltd. according to the optical property test method of JIS-K-7105 plastic.

(10) Evaluation of blocking resistance

The adhesive film was cut into a size of 150 mm in length x 50 mm in width, and the adhesive surface and the release surface were opposed to each other. Then, the adhesive film was put under a load of 20 kg and allowed to stand at 40 캜 for 7 days. Thereafter, the treated adhesive film was cut into a length of 25 mm width x 100 mm, and a tensile tester Tensilon UT-IIIL manufactured by Toyo Seiki Co., Ltd. was used to cut 180 The resistance value [cN / 25 mm] when peeling was measured.

(11) Thickness variation

Anritsu FILM THICKNESS TESTER KG601A and K306C.

Measurement speed 0.01 sec

Feeding speed 1.5 m / min

HIGH CUT OFF

Thinning processing OFF

A sample having a length of 40 mm with respect to the winding direction at the time of producing the film and a length of 500 mm with respect to the direction perpendicular to the winding direction was cut out and the continuous thickness in the direction perpendicular to the winding direction was measured under the above conditions. Based on the results obtained by the measurement, the thickness variation ratio was obtained by the following formula. The measurement was carried out five times for one sample, and the average value thereof was defined as the rate of thickness variation of the sample.

(%) = [(Maximum value of thickness - minimum value of thickness) / average value of thickness] x 100

[Example 1]

(Preparation of base layer)

100% by weight of homopolypropylene polymer (FLX80E4, manufactured by Sumitomo Chemical Co., Ltd., tensile modulus of elasticity: 1500 MPa) was melt-extruded with a 60 mm phi single screw extruder (L / D: 22.4)

(Production of adhesive layer)

(L / D: 19) of 98% by weight of an olefinic elastomer (JERAS MC707, manufactured by Mitsubishi Chemical Corporation) and 2% by weight of a heat stabilizer master batch (MB) containing 50,000 ppm of Irganox 1076, To obtain a pressure-sensitive adhesive layer.

(Preparation of release layer)

50% by weight of a propylene-ethylene block copolymer (Nippon Polypropylene BC3HF) and 50% by weight of a propylene-ethylene random copolymer (SUMITOMOCHA CHEMICAL: WF836DG3) were melt-extruded by a 65 mmφ single screw extruder (L / Thereby forming a release layer.

(Production of film)

The multilayer extrusion was carried out in a three-layer T die (multi-manifold type, lip width 250 mm, lip gap 1 mm) at 250 占 폚 with the substrate layer, the adhesive layer and the release layer melted in each extruder. The extruded film was blown onto a casting roll having a temperature of 20 DEG C with an air knife and was pulled at a speed of 12 m / min to be cooled and solidified to obtain a base layer thickness of 35 mu m, a pressure-sensitive adhesive layer thickness of 10 mu m, 3-layer undrawn film.

As a result of evaluating the properties of the film, it was found that a smooth adhesive layer was formed, had adhesiveness at room temperature, had no contact irregularity between an adherend and an adhesive layer, had a small increase in adhesive strength after adhesion with an adherend, And there was no blocking between the releasing layer and the adhesive layer, so that the handling property was good.

[Example 2]

50% by weight of a resin of the base layer and a homopolypropylene polymer (FLX80E4, manufactured by Sumitomo Chemical Co., Ltd., tensile modulus of elasticity: 1500 MPa ) Was changed to 50% by weight. This film also has a smooth adhesive layer, has adhesiveness at room temperature, has no contact unevenness between an adherend and an adhesive layer, has a small increase in adhesive force after adhesion with an adherend, has excellent appearance, There was no blocking between layers and the handling was good.

[Example 3]

The base layer and the release layer were produced in the same manner as in Example 1. The adhesive layer and the film were produced as follows. This film also has a smooth adhesive layer, has adhesiveness at room temperature, has no contact unevenness between an adherend and an adhesive layer, has a small increase in adhesive force after adhesion with an adherend, has excellent appearance, There was no blocking between layers and the handling was good.

(Adhesive layer)

50/50) of homopolypropylene resin (FLX80E4, manufactured by Sumitomo Chemical Co., Ltd., tensile modulus of elasticity: 1500 MPa) was mixed with amorphous PP (Tapselene H3522A manufactured by Sumitomo Chemical Co., Ltd., heat of crystal fusion and crystallization heat of 28 J / 50% by weight was melt-extruded with a 45 mm? Twin-screw extruder (L / D: 19) to obtain an adhesive layer.

(Production of film)

The multilayer extrusion was carried out in a three-layer T die (multi-manifold type, lip width 250 mm, lip gap 1 mm) at 250 占 폚 with the substrate layer, the adhesive layer and the release layer melted in each extruder. The extruded film was blown onto a casting roll at a temperature of 20 DEG C with an air knife and pulled at a speed of 12 m / min. After cooling and solidifying, the surface of the pressure-sensitive adhesive layer was subjected to corona treatment so that the surface tension was 37 mN / m To obtain a three-kind three-layer unoriented film having a base layer thickness of 30 占 퐉, a pressure-sensitive adhesive layer thickness of 15 占 퐉 and a release layer thickness of 5 占 퐉.

This film also exhibited good characteristics as in Example 1.

[Comparative Example 1]

A film was prepared in the same manner as in Example 1 except that the amount of the olefinic elastomer (Mitsubishi Chemical's Jarasu MC707) was changed to 100 wt%.

As a result of evaluating the characteristics of the film, it was found that a smooth adhesive layer was formed, had adhesiveness at room temperature, had no contact irregularity between the adherend and the adhesive layer, exhibited excellent appearance and had a small blocking between the releasing layer and the adhesive layer However, the increase in adhesion after adhesion with the adherend was large.

[Comparative Example 2]

The prescription of the pressure-sensitive adhesive layer was changed in accordance with the prescription of the pressure-sensitive adhesive layer with an amorphous PP (Tifselene H3522A, crystalline heat of fusion and a crystallization heat amount of 28 J / g) and homopolypropylene resin (FLX80E4 manufactured by Sumitomo Chemical Co., MPa) were mixed at a ratio of 80/20 wt%, and a film was produced in the same manner as in Example 3 except that the corona treatment was not performed.

As a result of evaluating the characteristics of the film, it was found that a smooth adhesive layer was formed, had adhesiveness at room temperature, had no contact irregularity between the adherend and the adhesive layer, exhibited excellent appearance and had a small blocking between the releasing layer and the adhesive layer However, the increase in the adhesive force after adhesion with the adherend was large, and the adherend was found to be contaminated.

[Comparative Example 3]

The prescription of the pressure-sensitive adhesive layer was changed to 95% by weight of an olefinic elastomer (Mitsubishi Chemical's Jarasu MC707) and 5% by weight of a heat stabilizer master batch (MB) containing 50000 ppm of Irganox 1076, A film was produced in the same manner as in Example 1 except that the corona treatment was performed so that the tension was 45 mN / m.

As a result of evaluating the characteristics of the film, a smooth adhesive layer was formed and had a stickiness at room temperature, but the adhesive strength was significantly reduced in the course of time.

[Comparative Example 4]

The base layer and the pressure-sensitive adhesive layer were the same as in Example 1 except that the release layer and the composition of each layer were changed to the following contents to obtain an unoriented three-layer three-layer film in the same manner as in Example 1.

(Preparation of release layer)

100 weight% of propylene-ethylene block copolymer (manufactured by Goodallomer: PC523A) was melt-extruded with a 65 mm? Single axis extruder (L / D: 25) to obtain a release layer.

(Production of film)

The multilayer extrusion was carried out in a three-layer T die (multi-manifold type, lip width 250 mm, lip gap 1 mm) at 250 캜 with the substrate layer, the adhesive layer and the release layer being melted in each extruder. The extruded film was blown onto a casting roll having a temperature of 20 DEG C with an air knife and pulled at a speed of 12 m / min to cool and solidify to form a base layer thickness of 40 mu m, an adhesive layer thickness of 5 mu m, a release layer thickness of 5 mu m 3-layer undrawn film.

As a result of evaluating the properties of the film, the adhesiveness at room temperature was slightly lowered, the surface roughness of the adhesive layer was high, contact irregularity between the adherend and the adhesive layer was seen, and the contact area between the adherend and the adhesive surface was small. Further, it was foamed at the time of the high-temperature treatment after the adhesion, and the appearance was deteriorated after heating. There was no blocking between the releasing layer and the adhesive layer and the handling property was good.

[Comparative Example 5]

The substrate layer and the adhesive layer were formed in the same manner as in Example 1 except that the release layer was changed to the following contents and the substrate layer thickness was 35 占 퐉 and the pressure sensitive adhesive layer thickness was 10 占 퐉, 3-layer unoriented film having a thickness of 5 탆 was obtained.

(Releasing layer)

100 weight% of a homopolypropylene resin (FLX80E4, manufactured by Sumitomo Chemical Co., Ltd.) was melt-extruded with a 65 mm phi single screw extruder (L / D: 25) to prepare a release layer.

As a result of evaluating the characteristics of the film, a smooth adhesive layer was formed, and the adhesive property at room temperature was not observed. The contact irregularity between the adherend and the adhesive layer was not observed, and the contact area between the adherend and the adhesive surface was sufficient. Further, there was no foaming at the time of high-temperature treatment after bonding, and appearance after heating was good, but the blocking between the release layer and the adhesive layer was strong, and there was a problem in handleability.

The results are shown in Table 1 below.

The pressure-sensitive adhesive film of the present invention has a low blocking between the pressure-sensitive adhesive films, particularly, even after the pressure-sensitive adhesive film is stored in a roll state, the blocking is small and the processability is excellent. Can be used for a wide range of applications such as synthetic resin plates, fancy plywood, metal plates and painted steel plates, baking painting of automobiles, and printed boards, and thus contributes to industry.

Claims (7)

A pressure-sensitive adhesive film comprising a base layer comprising a polypropylene resin, a pressure-sensitive adhesive layer containing a polyolefin-based elastomer on one surface thereof, and a release layer laminated on the opposite surface thereof, Wherein the roughness SRa is not less than 0.080 mu m and not more than 0.130 mu m and the average surface roughness SRa of the surface of the adhesive layer is not less than 0.010 mu m and not more than 0.025 mu m and the adhesive film is adhered to an acrylic plate, The area ratio of the contact portion of the adhesive film with the acrylic plate calculated by observing the state of the contact surface was 90% or more and 100% or less, and the adhesive film was peeled off after 24 hours at 23 占 폚 after adhering to the acrylic plate The amount of the bleed water of the polymer component on the adhesive surface and the acrylic plate at the time of adhesion is a1, the amount of the bleed water of the antioxidant is b1, (A2-a1) x2- (b2-b1) is -50 mg, when the amount of the bleeding water of the polymer component on the peeled adhesive surface and the acrylic plate is a2 and the amount of the antioxidant is b2 / m ² to 50 mg / m ² , and the film haze is in the range of 1 to 40%. The adhesive film according to claim 1, wherein the average surface roughness SRa of the adhesive layer is 0.020 mu m or less. A film roll comprising the film according to claim 1, wherein the film roll has a width of 450 mm or more and a length of 300 m or more. delete delete delete delete

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