TW201829199A - Release film and protective film - Google Patents

Abstract

Provided are a release film having excellent heat resistance, appearance, mechanical characteristics, followability, stain resistance and release properties; and a protective film having a release layer that exhibits the aforementioned characteristics. The release film has at least one release layer, and the release layer is characterized by comprising components (A) and (B). (A) 60 wt% or more of at least one type of polyolefin selected from among polyethylene, polypropylene and polybutene. (B) 0.1-40 wt% of an ultrahigh molecular weight polyethylene having an intrinsic viscosity [[eta]] of 8 dl/g or more. Furthermore, the protective film has an adhesive layer on the outermost layer that faces the release layer.

Description

   Release film and protective film   

The present invention relates to a release film and a protective film having a release film. In addition to being used as an adhesive material, an adhesive film, and a release film for a sheet, the release film of the present invention is excellent in heat resistance, appearance, mechanical properties, followability, pollution resistance, and release property, and can be used as a release film. It is suitably used as a release film for a printed circuit board, a release film for a flexible printed circuit board, a release film for prepreg molding, etc., which requires heat resistance, and is suitably used. Furthermore, by providing an adhesive layer on the outermost layer, it can be suitably used as a protective film with excellent unwinding property, heat resistance, stain resistance, and appearance.

Release film is widely used as an engineering film for improving the handling workability of adhesive materials and adhesive films and for manufacturing various molded articles. In particular, a release film having heat resistance is used as a step film in a heating step, such as a printed board manufacturing step, a prepreg forming step, an in-mold label step, and the like, and has a high utilization value.

For example, in the manufacturing steps of a printed circuit board, a flexible printed circuit board, or the like, a release film can be used in order to prevent the cover film from being bonded to the hot plate.

As a release film, a polyester film, a fluorine-based resin film, an unstretched polyester film, an alicyclic polyolefin film, a polymethylpentene film, etc., which have been coated with a silicone release material, have been proposed. (Patent Documents 1 to 4)

However, such films may have insufficient followability to printed substrates and molded bodies, insufficient release properties after press processing at high temperatures, and problems due to transfer of molded articles.

One film with an adhesive material on its outer layer is widely used as a protective film for optical components and building materials. When the protective film with relatively high adhesive force is used as a roll, the adhesive layer and the layer on the opposite side of the adhesive layer are in close contact, so the rollability from the roll is not good. When the unwinding property of the self-winding roll is not good, there are cases in which an excessive load is applied to the unwinding device, the film is deformed, and the appearance is affected. When used as a protective film for an optical member, deformation of the film and poor appearance are related to poor quality of the adherend.

In order to solve such problems, Patent Document 5 proposes a film having a release film composed of an α-olefin (co) polymer having 4 or more carbon atoms and a pressure-sensitive adhesive layer containing a styrene-based elastomer. However, with this method, there are cases where the release property (self-winding property from the roll) is insufficient and the appearance of the film is not good.

Prior art literature Patent literature

Patent Document 1 Japanese Patent Laid-Open No. 2-175247

Patent Document 2 Japanese Patent Application Laid-Open No. 5-283862

Patent Document 3 Japanese Patent Laid-Open No. 2006-321114

Patent Document 4 Japanese Patent Laid-Open No. 2-175247

Patent Document 5 Japanese Patent No. 6056378

The object of the present invention is to solve the above problems and provide a release film and self-rolling reel, heat resistance, and stain resistance with excellent heat resistance, appearance, mechanical properties, followability, stain resistance, and release properties. 2. Excellent appearance protective film.

The present inventors have conducted careful research and development in order to solve the above problems, and as a result, have found that the object can be achieved by the following constitution.

That is, the present invention has the following features.

(1) A release film, which is a release film having a release layer, characterized in that the release layer has the following (A), (B): (A) 60 to 99.9% by weight of polyethylene, polymer Polyolefin resin of at least one selected from propylene and polybutene; (B) Ultra-high molecular weight polyethylene having a limiting viscosity [η] of 0.1 to 40% by weight of 8 dl / g or more.

(2) A release film, which is a release film having a release layer, characterized in that the release layer has the following (A), (B), and (C): (A) 60 to 99.8% by weight of Polyolefin resin selected from polyethylene, polypropylene, and polybutene; (B) Ultra-high molecular weight polyethylene having a limiting viscosity [η] of 0.1 to 39.9% by weight 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 ultra-high molecular weight polyethylene forms island-shaped particles in the release layer, and the island-shaped particle diameter of the island-shaped particles is 3 to 100 μm.

(4) The release film according to any one of (1) to (3), wherein the release force after the release film is heated at 180 ° C. × 4 MPa and the polyimide film is brought into contact with the pressure of 0.5 N / 25mm or less.

(5) The release film according to any one of (2) to (4), wherein the release material is a hydrosilylated polyolefin.

(6) A protective film having the release layer of the release film according to any one of (1) to (5), and an outermost layer of the multilayer film composed of at least two layers is an adhesive layer.

(7) The protective film according to (6), wherein the adhesive layer has an olefin-based 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 used for manufacturing a printed circuit board or for manufacturing a flexible printed circuit board.

(10) The protective film according to any one of (6) to (8), which is for an optical film.

With the constitution of the present invention, it can be used as a release film and self-rolling reel, heat resistance, and pollution resistance with excellent heat resistance, appearance, mechanical properties, followability, pollution resistance, and release properties. Protective film with excellent properties and appearance.

The release layer of the release film of the present invention preferably contains (A) a polyolefin resin selected from at least one of polyethylene, polypropylene, and polybutene, and (B) an limiting viscosity [η] of 8 dl / g The above ultra-high molecular weight polyethylene.

Polyethylene, polypropylene, and polybutene can be used without particular limitation as long as they exhibit release properties described later. Examples of polyethylene include high-pressure low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE). Examples of polypropylene include homogeneous polypropylene, random polypropylene, and block polypropylene. Examples of the polybutene include homogeneous polybutene, a butene-ethylene copolymer, and a butene-propylene copolymer. In order to improve heat resistance and release properties, these polyolefin resins can be crosslinked. As the crosslinking method, a conventional crosslinking method such as electron beam crosslinking, dynamic crosslinking in the presence of a peroxide, and the like can be used.

As the ultrahigh molecular weight polyethylene, for example, a granular ultrahigh molecular weight polyethylene described in Japanese Patent Application Laid-Open No. 2006-206769 is suitable. The limiting viscosity [η] of the ultra-high molecular weight polyethylene is 8 dl / g or more, and preferably 10 dl / g or more. The average particle size of the particles is preferably from 3 μm to 100 μm. It is preferably in a range of 4 to 50 μm, and more preferably in a range of 4 to 20 μm. The average particle diameter can be obtained by a conventional method for measuring the diameter of fine particles such as the Coulter counter method. When the granular average particle diameter is less than 3 μm, the release property may be insufficient and inferior, and when it is larger than 100 μm, it may be the cause of fish eyes, which is not preferable. The ultra-high molecular weight polyethylene used in the present invention can be crosslinked in order to improve heat resistance and release properties. As the crosslinking method, a conventional crosslinking method such as electron beam crosslinking, dynamic crosslinking in the presence of a peroxide, and the like can be used.

The composition ratio of (A) polyolefin resin and (B) ultra-high molecular weight polyethylene in the release layer is: (A) 60 to 99.9% by weight, preferably 70 to 99.8% by weight, and more preferably 80 to 99.8 (B) is 0.1 to 40% by weight, preferably 0.2 to 30% by weight, and more preferably 0.2 to 20% by weight. When the polyolefin resin is less than 60% by weight, in order to exhibit release properties, it is necessary to add a large number of conventional release resins and release materials. 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 containing a polyolefin resin and an ultra-high molecular weight polyethylene according to the purpose of improving the release property.

As the release material, a conventional release material can be used in a range that exhibits the characteristics as the release film of the present invention. Specific examples include a silicone-based release material, a reaction product of an ethylene / vinyl alcohol copolymer and a stearyl isocyanate, and a hydrosilylated polyolefin. Among these, from the viewpoints of pollution resistance and release properties, a hydrosilylated polyolefin is preferred. The hydrosilylated polyolefin system can be obtained, for example, by a method described in Japanese Patent Application Laid-Open No. 2010-37555. For example, a hydrosilylation can be performed on a polyolefin such as polyethylene having vinyl at both ends or a single end.

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

The release film of the present invention is preferably: the ultra-high molecular weight polyethylene forms island-shaped particles in the release layer, and the island-shaped particle diameter of the island-shaped particles is preferably 3 to 100 μm. It is preferable to form island particles of 4 to 70 μm, and it is more preferable to form island particles of 4 to 40 μm. The island-like particle size of the ultra-high molecular weight polyethylene can be measured by conventional methods such as an optical microscope, a scanning electron microscope (SEM), and a transmission electron microscope (TEM). When the island-like particle diameter is less than 3 μm, the release property may be insufficient, and when it is larger than 100 μm, the appearance of the film may be poor and unsuitable.

The release film of the present invention is preferably: the peel force after the release film and the polyfluorene film are heated at 180 ° C. × 4 MPa, and the pressure is 0.5 N / 25 mm or less. It is preferably 0.3 N / 25 mm or less, and more preferably 0.1 N / 25 mm or less. By having such characteristics, it is possible to appropriately utilize applications requiring release properties at high temperatures, such as manufacturing steps for printed boards, flexible printed boards, and the like.

The release film of the present invention has at least one release layer. If necessary, a base material layer may be provided. 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 a release layer. As the substrate layer, in addition to conventional polyolefins such as polyethylene and polypropylene, polyesters, polyamides, and the like can also be used. When the release film of the present invention is used as a release film for manufacturing a printed circuit board, a preferable example of the base material layer includes a polymer having a hot melt tension (MT) of 1 g or more measured at 190 ° C. Made up of olefins. More preferred examples include those composed of polyolefins having a hot melt tension of 2 g or more, and even more preferred include those composed of polyolefins having a hot melt tension of 3 to 30 g. When the MT is less than 1 g, the heat resistance is not good, so it is not good. Examples of the polyolefin include polypropylene, polyethylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, and ion polymerization Resin. Preferable examples include polypropylene and polyethylene.

Examples of the polypropylene include, in addition to homogeneous polypropylene, random polypropylene, and block polypropylene, 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. The range of 0.2 to 20 g / min is preferable. When the MFR is less than 0.1 g / min, the productivity of the film may be insufficient, and when it exceeds 30 g / min, when it is used as a release film for the production of a printed substrate, it may cause resin after molding. Exudation is not good. The elastic modulus of polypropylene is preferably 800 MPa or less. The range of 20 to 600 MPa is preferable. When the elastic modulus exceeds 800 MPa, when it is used as a release film for manufacturing a printed circuit board, there is a case where the followability to the printed circuit board is 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 low-crystalline ethylene and carbon number Copolymer of 3 to 10 α-olefins. Preferred examples include a MFR (melt flow rate) (190 ° C) of 0.01 to 30 g / min (more preferably 0.05 to 20 g / min), a density of 0.870 to 0.945 g / cm ³ (more preferably 0.890 to 0.0940 g / cm ³ ) of high pressure low density polyethylene (LDPE), linear low density polyethylene (LLDPE). When the MFR is less than 0.01 g / min, the productivity of the film may be insufficient, and when it exceeds 30 g / min, when it is used as a release film for the production of a printed circuit board, it may cause resin after molding Exudation is not good. When the density is less than 0.870 g / cm ³ , the productivity of the film may be insufficient, and when the density is more than 0.945 g / cm ³ , when it is used as a release film for the production of a printed circuit board, The printed circuit board has insufficient followability, so it is not good. The thickness of the release film of the present invention is preferably 5 to 1000 μm. It is preferably 10 to 500 μm, and more preferably 15 to 300 μm. In the case of a multilayer film of a substrate layer and a release layer, the thickness of the release layer is preferably 0.5 to 100 μm. It is preferably 1 to 50 μm, and more preferably 2 to 30 μm. The thickness of the substrate layer is preferably 5 to 800 μm. It is preferably 7 to 400 μm, and more preferably 10 to 300 μm.

The release film of the present invention can be produced by a conventional method capable of producing polyethylene and polypropylene films such as blow molding and T-die molding. Even when forming a multilayer film, a method of multi-layer extrusion molding, dry lamination of a substrate film and a release film prepared in advance, and lamination of a substrate film and a release film can be used. Method, etc.

In the release layer and / or the base material layer of the release film of the present invention, an antioxidant, a weathering agent, and a crystal nucleating agent may be added in a range where the effects of the present invention are not impaired, and for the purpose of improving formability and the like. , Inorganic fillers, antistatic agents, and other conventional additives or fillers that can be used in polyolefins.

The present invention can be used as a protective film by providing an adhesive layer.

As the adhesive used in the adhesive layer, in addition to the conventional alkyl acrylate-based adhesives and rubber-based hot-melt adhesives, olefin-based polymers, styrene-based elastomers, and the like can be used. Preferred are olefin-based polymers and styrene-based elastomers.

As the olefin polymer, preferred examples are: ethylene homopolymers such as high-density polyethylene and high-pressure low-density polyethylene; copolymers of ethylene and α-olefins having a carbon number of 3 to 20; ethylene and vinyl esters, Copolymers of acrylic esters; homopolymers of propylene; copolymers of propylene with ethylene and α-olefins having a carbon number of 4 to 20; other polymers and copolymers mainly containing an α-olefin of 4 or more carbon atoms. Specific examples include ethylene-butene copolymer, ethylene-pentene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, and ethylene-acrylic acid Methyl ester copolymer, ethylene-ethyl acrylate copolymer, soft propylene homopolymer, propylene-ethylene copolymer, propylene-ethylene-butene copolymer, propylene-butene copolymer, propylene-4-methylpentene copolymerization Materials, 4-methylpentene polymers, etc.

Examples of the styrene-based elastomer include a styrene-butadiene copolymer (SB), a styrene-butadiene-styrene copolymer (SBS), a styrene-isoprene copolymer (SI), Copolymers of styrene and conjugated diene, such as styrene-isoprene-styrene copolymer (SIS), and their hydrides (styrene-ethylene-butene-styrene copolymer (SEBS), Styrene ethylene-butene-styrene copolymer (SEPS), etc.), styrene-isobutylene copolymer (SIB), styrene-isobutylene-styrene (SIBS), and the like.

The olefin-based polymer and the styrene-based elastic system may be used alone, or two or more of them may be used in combination. For the purpose of adjusting the adhesiveness, an olefin-based polymer and a styrene-based elastomer may be used in combination.

In the adhesive layer of the protective film of the present invention, an adhesive imparting agent may be added to the adhesive layer for the purpose of making the adhesive force desired. Examples of the adhesion-imparting agent include commercially available resin groups such as rosin-based, terpene-based, and coumarin-indene-based resins.

The protective film of the present invention has an adhesive layer on the outermost layer in the release film of the present invention. In the present invention, a base material layer may be provided as needed. Specific examples of the layer configuration include a release layer / adhesive layer, a release layer / base material layer / adhesive layer. When the adhesion between the layers is insufficient, an adhesive layer composed of an adhesive may be provided between the layers. As the base material layer, as described above, in addition to conventional polyolefins such as polyethylene and polypropylene, polyesters, polyamides, and the like can also be used.

The thickness of the protective film of the present invention is preferably 5 to 1000 μm. It is preferably 10 to 500 μm, and more preferably 15 to 300 μm. The thickness of the release film should be 0.5 to 100 μm. It is preferably 1 to 50 μm, and more preferably 1 to 30 μm. The thickness of the substrate layer is preferably 0 to 800 μm. It is preferably 7 to 400 μm, and more preferably 10 to 300 μm. The thickness of the adhesive layer should be 0.5 to 100 μm. It is preferably 1 to 50 μm, and more preferably 1 to 30 μm.

The protective film of the present invention can be produced by a conventional method capable of producing polyethylene and polypropylene films, such as blow molding and T-die molding. Even when making a multilayer film, you can use multi-layer extrusion molding, dry lamination of a pre-prepared substrate layer film and a release film, and extrude the release layer and the adhesive layer to the substrate. Laminating method.

Examples

Hereinafter, the release film of the present invention will be described in detail based on specific examples, but the present invention is not limited to these examples. The measurement and evaluation were performed by the methods described below.

    (1) Peeling force from polyimide film    

A release film having a size of 15 cm × 15 cm and a polyimide film having a thickness of 50 μm (“Kapton (registered trademark)” 200H manufactured by Toray DuPont Co., Ltd.) were stacked, and a heating press was used at a pressure of 4 MPa and a temperature of 180 ° C. Contact at temperature for 5 minutes. After returning to room temperature, the peeling force of the release film and the polyimide film was measured using a tensile tester, and the obtained value was regarded as the peeling force.

    (2) the average roughness of the release layer (Ra, Rz)    

The release film was stored in an environment at room temperature of 23 ° C and a humidity of 50RH% for more than 3 days after the preparation. Then, the Surfline Coder "ET4000A" manufactured by Kosaka Laboratory was used to measure the average roughness of the centerline (Ra) and the ten-point average roughness. (Rz).

    (3) Hot melt tension    

Using a hot-melt tension tester (hole diameter 2.1mm, L / D = 4), at 190 ° C, decrease the speed of the piston by 5.5mm / min, and increase the drawing speed by 50m / min. , Take the tension value of the strand breaking speed as the hot melt tension (MT).

    (4) Island shape particle size    

The release layer was observed from the surface using an optical microscope. The island-like particle size was measured.

    (5) Release from flexible printed circuit boards    

Each determination is as follows.

：: The release film is easily peeled from the flexible printed board after pressing.

×: After pressing, the release film cannot be peeled off from the flexible printed circuit board and is fixed.

    (6) Adhesive followability    

Each determination is as follows.

○: Between the wiring patterns of the substrate, the adhesive is completely embedded.

×: Between the wiring patterns of the substrate, the adhesive was not sufficiently embedded, and air bubbles remained.

    (7) Exposed state    

Each determination is as follows.

○: The release film is not exposed from the size of the flexible printed circuit board (10 mm or more).

×: The release film is largely exposed from the size of the flexible printed circuit board (10 mm or more).

    (8) Peeling force of release layer / adhesive layer    

Using a film with a size of 50mm × 100mm, the release layer and the adhesive layer were bonded by using a 2kg roll. After standing at 23 ° C for one day, the peeling force of the release layer and the adhesive layer was measured by a tensile tester, and the obtained value was taken as the peeling force.

    (9) Releasability from the reel    

A film with a length of 1000m is wound into a roll. The state (stability, appearance) when the film was repeatedly output from the roll at a speed of 5 m / minute was evaluated as rollability.

    <Example 1>    

The following composition was used as a release layer: MFR (230 ° C, 2.16kg load) was 8g / 10 minutes, and the limiting viscosity [η] of the rubber component (called cold xylene soluble component) (at 135 ° C) Measured in decahydronaphthalene) 2.8 dl / g, the amount of rubber (cold xylene soluble content) is 137.5% by weight of block polypropylene 97.5% by weight; the limiting viscosity [η] is 20 dl / g, average particle diameter 1.5% by weight of a granular ultra-high molecular weight polyethylene of 11 μm; and a hydrosilation polymer obtained by silanizing a terminal vinyl polyethylene having a melting point of 116 ° C. and a number average molecular weight of 730 according to the method of Japanese Patent Laid-Open No. 2010-37555. 1.0% by weight of ethylene.

Random polypropylene (propylene-ethylene-butene copolymer) with a melting point of 142 ° C, MFR (230 ° C, 2.16kg load) of 6 g / 10 minutes, and hot melt tension (190 ° C) of 0.5 g was used as an intermediate layer (base Material layer).

For these, a T-die composite film forming machine was used to obtain two types of three-layer films 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 made into a release layer / intermediate layer / release layer = 10/80/10 μm.

The release layer had Ra of 0.50 μm and Rz of 8.7 μm. The island-like particle size is in the range of 9 to 15 μm.

As a result of measuring the peel force of the obtained release film and polyimide film after heating and pressing at 180 ° C. and 4 MPa, it was 0.01 N / 25 mm. The peeling force after being brought into contact with the polyfluorene film at a high temperature is small, and there is no cracking when the release film is peeled off, and the heat resistance and the release property are good.

The evaluation results for the flexible printed circuit board are as follows.

Release from flexible printed circuit boards: ○

Adhesive followability: ○

Exposed state: ×

    <Example 2>    

The following composition was used as a release layer: MFR (230 ° C, 2.16kg load) was 8 g / 10 minutes, and the limiting viscosity [η] of the rubber component (measured in decalin at 135 ° C) was 2.8 dl / g, 97.5 wt% of block polypropylene with a rubber content (amount of cold xylene solubles) of 13 wt%; granular ultra-high molecular weight polyethylene 1.5 with an average particle diameter of 11 μm and an ultimate viscosity [η] of 20 dl / g 1.0% by weight of silylated polyethylene obtained by silylation of a terminal vinyl polyethylene having a melting point of 116 ° C. and a number average molecular weight of 730 according to the method of Japanese Patent Application Laid-Open No. 2010-37555.

A 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 minutes, and hot melt tension (190 ° C) of 7.0 g was used as an intermediate layer ( Substrate layer).

For these, a T-die composite film forming machine was used to obtain two types of three-layer films 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 made into a release layer / intermediate layer / release layer = 10/80/10 μm.

The release layer had Ra of 0.51 μm and Rz of 8.8 μm. The island-like particle size is in the range of 9 to 15 μm.

As a result of measuring the peel force of the obtained release film and polyimide film after heating and pressing at 180 ° C. and 4 MPa, it was 0.01 N / 25 mm.

The evaluation results for the flexible printed circuit board are as follows.

Release from flexible printed circuit boards: ○

Adhesive followability: ○

Exposed state: ○

    <Example 3>    

An intermediate layer (base material layer) was made of a high-density polyethylene having an MFR (190 ° C, 2.16 kg load) of 7 g / 10 minutes and a hot melt tension (190 ° C) of 0.8 g. An operation was performed to form a release film.

The release layer had Ra of 0.45 μm and Rz of 8.5 μm. The island-like particle size is in the range of 9 to 15 μm.

The peeling force between the obtained release film and the polyimide film was 0.02 N / 25 mm. The peeling force after being brought into contact with the polyfluorene film at a high temperature is small, and there is no cracking when the release film is peeled off, and the heat resistance and release properties are good.

The evaluation results for the flexible printed circuit board are as follows.

Release from flexible printed circuit boards: ○

Adhesive followability: ○

Exposed state: ×

    <Example 4>    

A release film was prepared in the same manner as in Example 1 except that the following composition was used as a release layer: MFR (230 ° C, 2.16 kg load) was 8 g / 10 minutes, and the rubber component The limiting viscosity [η] (measured in decalin at 135 ° C) is 2.8 dl / g, the amount of rubber (amount of cold xylene solubles) is 135% by weight, and the block polypropylene is 98.5% by weight; the limiting viscosity [η] is 1.5% by weight of an electron beam irradiated material of a granular ultra-high molecular weight polyethylene having an average particle diameter of 11 μm at 20 dl / g.

The release layer had Ra of 0.47 μm and Rz of 8.8 μm. The island-like particle size is in the range of 9 to 15 μm.

The release force between the obtained release film and the polyimide film was 0.10 N / 25 mm. The peeling force after being brought into contact with the polyfluorene film at a high temperature is small, and there is no cracking when the release film is peeled off, and the heat resistance and release properties are good.

The evaluation results for the flexible printed circuit board are as follows.

Release from flexible printed circuit boards: ○

Adhesive followability: ○

Exposed state: ×

    <Comparative example 1>    

The following was used as a release layer, except that the same operation as in Example 1 was performed to form a release film: MFR (230 ° C, 2.16 kg load) was 4 g / 10 minutes, and the limiting viscosity of the rubber component [ η] (measured in decalin at 135 ° C) was 2.5 dl / g, and the amount of rubber (amount of cold xylene solubles) was 13% by weight of 100% by weight of the block polypropylene. The release layer had Ra of 0.2 μm and Rz of 3.0 μm.

No island-like particle size derived from ultra-high molecular weight polyethylene was observed.

The release force between the obtained release film and the polyimide film was 2.1 N / 25 mm. The peeling force after being brought into contact with the polyimide film at a high temperature is large, and deformation occurs when the release film is peeled off, and the heat resistance and release properties are insufficient.

The evaluation results for the flexible printed circuit board are as follows.

Release for flexible printed circuit boards: ×

Adhesive followability: ○

Exposed state: ×

    <Example 5>    

The following composition was used as a release layer: MFR (230 ° C, 2.16kg load) was 8 g / 10 minutes, and the limiting viscosity [η] of the rubber component (measured in decalin at 135 ° C) was 2.8 dl / g, 97.5 wt% of block polypropylene with a rubber content (amount of cold xylene solubles) of 13 wt%; granular ultra-high molecular weight polyethylene with a limiting viscosity [η] of 20 dl / g and an average particle diameter of 11 μm 1.5% by weight of the electron beam irradiation; and 1.0% by weight of silylated polyethylene obtained by silylation of 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

A random layer (propylene-ethylene-butene copolymer) having a melting point of 142 ° C and an MFR (230 ° C, 2.16 kg load) of 6 g / 10 minutes was used as an intermediate layer (base material layer).

A composition containing 40% by weight of a styrene-ethylene-butene copolymer (Dyronon 1321P manufactured by JSR Corporation), 10% by weight of a terpene-phenol based adhesion-imparting agent (TH130 manufactured by Yasuhara Chemical), and 50% by weight of high-pressure polyethylene Adhesive layer.

For these, a T-die composite film forming machine was used to obtain three types of three-layer films composed of a release layer, an intermediate layer, and an adhesive layer. The total thickness of the film is 40 μm, and the thickness of each layer is made of a release layer / intermediate layer / adhesive layer = 3/32/5 μm.

The release layer had Ra of 0.50 μm and Rz of 8.7 μm. The island-like particle size is in the range of 9 to 15 μm.

The release force of the release layer and the adhesive layer was 0.1 g / 25 mm. The rolling stability from the roll is good, and the appearance of the film after rolling is also good.

    <Comparative example 2>    

A protective film was prepared in the same manner as in Example 5 except that the following was used as a release layer: MFR (230 ° C, 2.16 kg load) was 4 g / 10 minutes, and the limiting viscosity of the rubber component [η ] (Measured in decalin at 135 ° C) was 2.5 dl / g, and the amount of rubber (amount of cold xylene solubles) was 13% by weight of 100% by weight of the block polypropylene. The release layer had Ra of 0.2 μm and Rz of 3.0 μm. No island-like particle size derived from ultra-high molecular weight polyethylene was observed.

The release force between the release layer and the adhesive layer was 15 g / 25 mm. The unwinding from the reel is irregular and unstable. After the unwinding, the tendon (stop mark) can be seen in the direction perpendicular to the unwinding direction.

    <Example 6>    

A protective film was prepared in the same manner as in Example 5 except that the following composition was used as a release layer: MFR (230 ° C, 2.16 kg load) was 8 g / 10 min. The limiting viscosity [η] (measured in decalin at 135 ° C) is 2.8 dl / g, and the amount of rubber (amount of cold xylene solubles) is 135% by weight of the block polypropylene 98.5% by weight; the limiting viscosity [ η] is 1.5% by weight of a granular ultra-high molecular weight polyethylene having an average particle diameter of 11 μm at 20 dl / g. The release layer had Ra of 0.47 μm and Rz of 8.8 μm. The island-like particle size is in the range of 9 to 15 μm.

The peel force of the release layer and the adhesive layer is 2g / 25mm. The rolling stability from the roll is good, and the appearance of the film after rolling is also good.

    <Example 7>    

A protective film was prepared in the same manner as in Example 5 except that the following composition was used as an adhesive layer: 90% by weight of styrene-isobutylene-styrene copolymer (SIBSTAR 062M manufactured by KANEKA), benzene 10% by weight of an ethylene-based adhesion-imparting agent (FTR6125 manufactured by Mitsui Chemicals). The release layer had Ra of 0.51 μm and Rz of 8.5 μm.

The release force of the release layer and the adhesive layer was 10 g / 25 mm. The roll-out stability from the reel is good. The appearance of the film after being rolled out was also good.

    <Comparative example 3>    

A protective film was prepared in the same manner as in Example 5 except that the following was used as a release layer: MFR (230 ° C, 2.16 kg load) was 4 g / 10 minutes, and the limiting viscosity of the rubber component [η ] (Measured in decalin at 135 ° C) was 2.5 dl / g, and the amount of rubber (amount of cold xylene solubles) was 13% by weight of 100% by weight of the block polypropylene. The release layer had Ra of 0.2 μm and Rz of 3.0 μm.

The release force between the release layer and the adhesive layer was 80 g / 25 mm. The unwinding from the reel is irregular and unstable. After the unwinding, the tendon (stop mark) can be seen in the direction perpendicular to the unwinding direction.

    <Example 8>    

A protective film was prepared in the same manner as in Example 5 except that the following composition was used as an adhesive layer: 90% by weight of styrene-isobutylene-styrene copolymer (SIBSTAR 062M manufactured by KANEKA), benzene 10% by weight of an ethylene-based adhesion-imparting agent (FTR6125 manufactured by Mitsui Chemicals). The release layer had Ra of 0.51 μm and Rz of 8.5 μm.

The release force of the release layer and the adhesive layer was 10 g / 25 mm. The rolling stability from the roll is good, and the appearance of the film after rolling is also good.

    <Example 9>    

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

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

Claims (10)

    A release film is a release film having a release layer, which is characterized in that the release layer has the following (A) and (B): (A) 60 to 99.9% by weight of polyethylene, polypropylene, and polyethylene At least one kind of polyolefin resin selected from butene; (B) Ultra-high molecular weight polyethylene having a limiting viscosity [η] of 0.1 to 40% by weight of 8 dl / g or more.         A release film is a release film having a release layer, which is characterized in that the release layer has the following (A), (B), and (C): (A) 60 to 99.8% by weight of polyethylene, Polyolefin resin selected from polypropylene and polybutene; (B) Ultra-high molecular weight polyethylene having a limiting viscosity [η] of 0.1 to 39.9% by weight of 8 dl / g or more; (C) 0.1 to 39.9% by weight Release material.         For example, the release film of claim 1 or 2, wherein the ultra-high molecular weight polyethylene forms island-shaped particles in the release layer, and the island-shaped particle diameter of the island-shaped 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 film and the polyimide film are heated and pressed at 180 ° C. × 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 a hydrosilylated polyolefin.         A protective film having a release layer according to any one of claims 1 to 5, and an outermost layer of a multilayer film composed of at least two layers is an adhesive layer.         The protective film according to claim 6, wherein the adhesive layer has an olefin-based 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.         The protective film according to any one of claims 6 to 8, which is for an optical film.