JP6575285B2 - Method for producing adhesive film - Google Patents

Description

  The present invention relates to a method for producing an adhesive film.

  Conventionally, a surface protective film has been used to protect the lens surface of a prism sheet used in a liquid crystal display. Since this surface protective film is for protecting the lens surface of the prism sheet from scratches and dirt in the manufacturing process, it is peeled off after the manufacturing process is completed and does not remain in the final product. Therefore, the surface protective film has (1) strong adhesive strength; it adheres to the adherend and does not peel off in the manufacturing process such as punching, (2) the adhesive progress is small; the adhesive strength at the time of peeling increases with time No (3) Less adhesive residue; adhesive properties such as no adhesive layer remaining on the surface of the adherend are required.

  As such a surface protective film, for example, an adhesive layer made of, for example, an ethylene-vinyl acetate copolymer (EVA) or a conjugated diene polymer is provided on one surface of a base material layer made of a thermoplastic resin such as an olefin resin. What is formed is known.

  As a method for producing a pressure-sensitive adhesive film such as a surface protective film, a method in which a pressure-sensitive adhesive is applied to a base material layer (see, for example, Patent Document 1), and a method in which the base material layer and the pressure-sensitive adhesive layer are collectively formed by a coextrusion method. (For example, refer to Patent Document 2 and Patent Document 3). In particular, a method for producing an adhesive layer by a co-extrusion method has been attracting attention in recent years because it is simple and can suppress production costs.

JP 2003-238927 A Japanese Patent Laid-Open No. 2003-041216 JP 2010-255007 A

  The level of adhesive properties (strong adhesive strength, low adhesive progress, low adhesive residue, etc.) and molding processability required with the rapid development of technology in recent years are increasing. There is a need for improvements.

  In particular, it is essential that the pressure-sensitive adhesive that can be used in the co-extrusion method is melted during molding and exhibits fluidity. However, such behavior means that the adhesive properties of the adhesive film change due to temperature changes. Therefore, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film produced by the co-extrusion method has a problem that the pressure-sensitive adhesive properties are lowered as the temperature increases.

  Therefore, some aspects of the present invention solve at least a part of the above-described problems, thereby improving production efficiency by the coextrusion method, reducing changes in adhesive properties due to temperature changes, and being excellent in adhesive properties. A method for producing an adhesive film having an adhesive layer is provided.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the method for producing an adhesive film according to the present invention is:
A step of preparing a composition for a substrate and a composition for an adhesive containing a thermoplastic resin (A) and a radical generator (B);
Producing a laminated film having a base material layer and an adhesive layer using a co-extrusion method of the base material composition and the adhesive composition;
Irradiating the adhesive layer of the laminated film with ultraviolet rays;
It is characterized by including.

[Application Example 2]
In the method for producing an adhesive film of Application Example 1,
The thermoplastic resin (A) can have a repeating unit derived from a conjugated diene compound and a repeating unit derived from an aromatic vinyl compound.

[Application Example 3]
In the production method of the adhesive film of Application Example 1 or Application Example 2,
The said composition for adhesives can contain the said radical generating agent (B) 0.1-10 mass parts with respect to 100 mass parts of said thermoplastic resins (A).

[Application Example 4]
In the method for producing an adhesive film of any one of Application Examples 1 to 3,
The irradiation amount of the ultraviolet light may be 10 to 5000 mJ / cm ² .

  According to the manufacturing method of the adhesive film which concerns on this invention, the production efficiency of the adhesive film which has a base material layer and an adhesive layer can be improved by using a coextrusion method. Further, according to the method for producing an adhesive film according to the present invention, the change in the adhesive property due to temperature change is small, the adhesive force to the adherend is high, the adhesive progress is small, and the adhesive remains on the adherend A pressure-sensitive adhesive film having a pressure-sensitive adhesive layer having excellent pressure-sensitive adhesive properties can be produced.

  Hereinafter, preferred embodiments according to the present invention will be described in detail. It should be understood that the present invention is not limited to only the embodiments described below, and includes various modifications that are implemented without departing from the scope of the present invention. In the present specification, “(meth) acrylic” is a concept encompassing both “acrylic” and “methacrylic”. Further, “˜ (meth) acrylate” is a concept encompassing both “˜acrylate” and “˜methacrylate”. “(Meth) allyl” is a concept encompassing both “allyl” and “methallyl”.

  In the present invention, the “adhesive film” refers to a film having an adhesive layer formed on at least one surface of a base material layer.

1. Manufacturing method of adhesive film The manufacturing method of the adhesive film which concerns on this embodiment prepares the composition for base materials, and the composition for adhesives containing a thermoplastic resin (A) and a radical generator (B). A step (hereinafter also referred to as a “raw material preparation step”), and a step of producing a laminated film having a base material layer and an adhesive layer using a co-extrusion method of the base material composition and the adhesive composition. (Hereinafter also referred to as “laminated film manufacturing step”) and a step of irradiating the adhesive layer of the laminated film with ultraviolet rays (hereinafter also referred to as “ultraviolet irradiation step”). Hereinafter, each step will be described in detail.

1.1. Raw material preparation step First, a base material composition for preparing a base material layer and an adhesive composition for preparing an adhesive layer are prepared.

1.1.1. Composition for base material The composition for base material for producing the base material layer preferably contains a thermoplastic resin. Of the thermoplastic resins, olefin resins are preferred.

  As the olefin resin, for example, polyethylene, polypropylene, and polybutene copolymers can be suitably used. Specifically, propylene-ethylene copolymer, propylene-butene-1 copolymer, butene-1-ethylene copolymer, propylene-ethylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene -Ethyl acrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-n-butyl acrylate copolymer, etc. can be mentioned. These thermoplastic resins can be used alone or in combination of two or more.

  The composition for a substrate contains a thermoplastic resin as a main component, but for the purpose of preventing deterioration, for example, an antioxidant, an ultraviolet absorber, a light stabilizer such as a hindered amine light stabilizer, an antistatic agent, and the like. For example, fillers such as calcium oxide, magnesium oxide, silica, zinc oxide, and titanium oxide, pigments, anti-tarnish agents, lubricants, anti-blocking agents, and the like can be appropriately added.

  It is preferable that MFR measured by 230 degreeC and a 21.2N load of the thermoplastic resin contained in the composition for base materials is 0.01-100 g / 10min, 0.1-80 g / 10min It is more preferable that Moreover, the thermoplastic resin contained in the base composition may be composed of only one kind of thermoplastic resin, or may be composed by mixing two or more kinds of thermoplastic resins. The base material layer may be a single layer or a multilayer of two or more layers. It is also possible to select a foam layer as the base material layer.

1.1.2. Composition for pressure-sensitive adhesives A composition for pressure-sensitive adhesives for producing a pressure-sensitive adhesive layer contains a thermoplastic resin (A) and a radical generator (B). Hereinafter, each component contained in the composition for adhesives used by this embodiment is demonstrated in detail.

1.1.2.1. Thermoplastic resin (A)
The thermoplastic resin (A) (hereinafter also simply referred to as “component (A)”) contained in the pressure-sensitive adhesive composition used in the present embodiment is used to produce a pressure-sensitive adhesive layer constituting a part of the pressure-sensitive adhesive film. Used for. As such a component (A), any resin having adhesiveness can be used without particular limitation. In addition, in this embodiment, in order to produce an adhesive film by a coextrusion method, it is preferable that a component (A) has a repeating unit derived from a conjugated diene compound and a repeating unit derived from an aromatic vinyl compound. . Hereinafter, the repeating unit constituting the component (A) and the structure and properties of the component (A) will be described in order.

<Repeating unit derived from conjugated diene compound>
The component (A) preferably has a repeating unit derived from a conjugated diene compound. Examples of the conjugated diene compound include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene and the like. , One or more selected from these. As the conjugated diene compound, 1,3-butadiene is particularly preferable.

  In the component (A), the content of the repeating unit derived from the conjugated diene compound is preferably 30 to 95 parts by mass when the total repeating unit of the component (A) is 100 parts by mass, and preferably 35 to 90 parts by mass. More preferably, it is a part. When the content ratio of the repeating unit derived from the conjugated diene compound is in the above range, it becomes easy to produce an adhesive film excellent in viscoelasticity and strength, and the adhesive properties of the adhesive layer are further improved.

<Repeating unit derived from aromatic vinyl compound>
The component (A) preferably has a repeating unit derived from an aromatic vinyl compound. Examples of the aromatic vinyl compound include styrene, tert-butylstyrene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, divinylbenzene, 1,1-diphenylstyrene, vinylnaphthalene, vinylanthracene, N, N— Examples thereof include diethyl-p-aminoethylstyrene and vinylpyridine. Among these, styrene is particularly preferable.

  In the component (A), the content of the repeating unit derived from the aromatic vinyl compound is preferably 5 to 70 parts by mass when the total repeating unit of the component (A) is 100 parts by mass. More preferably, it is part by mass. When the content ratio of the repeating unit derived from the aromatic vinyl compound is in the above range, the tackiness of the adhesive layer becomes better.

<Other repeating units>
Component (A) may have a repeating unit other than the above. Examples of the repeating unit other than the above include a repeating unit derived from an unsaturated carboxylic acid ester, a repeating unit derived from an unsaturated carboxylic acid, and a repeating unit derived from an α, β-unsaturated nitrile compound.

  The unsaturated carboxylic acid ester is preferably a (meth) acrylic acid ester. Specific examples of such (meth) acrylic acid esters include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, (meth ) N-butyl acrylate, i-butyl (meth) acrylate, n-amyl (meth) acrylate, i-amyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth ) 2-ethylhexyl acrylate, n-octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylic Ethylene glycol, di (meth) acrylic acid ethylene glycol, di (meth) acrylic acid propylene glycol , Trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, allyl (meth) acrylate, ethylene di (meth) acrylate, etc. It can be one or more selected from these. Among these, one or more selected from methyl (meth) acrylate, ethyl (meth) acrylate and 2-ethylhexyl (meth) acrylate is preferable, and methyl (meth) acrylate is particularly preferable. preferable.

  Specific examples of the unsaturated carboxylic acid include mono- or dicarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and the like. One type selected from these That can be the end. In particular, at least one selected from acrylic acid, methacrylic acid and itaconic acid is preferable.

Specific examples of the α, β-unsaturated nitrile compound include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile, vinylidene cyanide, and one or more selected from these. Can be. Of these, at least one selected from acrylonitrile and methacrylonitrile is preferable, and acrylonitrile is particularly preferable.

  Moreover, a component (A) may further have a repeating unit derived from the compound shown below. Examples of such compounds include fluorine-containing compounds having an ethylenically unsaturated bond such as vinylidene fluoride, tetrafluoroethylene, and hexafluoropropylene; ethylenically unsaturated carboxylic acids such as (meth) acrylamide and N-methylolacrylamide. Acid alkyl amides; Vinyl acetates, vinyl acetates, vinyl propionates, etc .; Acid anhydrides of ethylenically unsaturated dicarboxylic acids; Monoalkyl esters; Monoamides; Aminoethylacrylamide, dimethylaminomethylmethacrylamide, Methylaminopropylmethacrylamide Examples thereof include aminoalkylamides of ethylenically unsaturated carboxylic acids such as, and can be one or more selected from these.

<Structure, characteristics and synthesis method of thermoplastic resin (A)>
Although it does not specifically limit as a component (A) in this invention, ABA type | mold in which the block of the repeating unit derived from an aromatic vinyl compound and the block of the repeating unit derived from a conjugated diene compound exist alternately. A block copolymer is preferably used. Specifically, a block copolymer of styrene and a conjugated diene compound such as butadiene or isoprene, or a hydrogenated product thereof is preferable. From the viewpoint of durability, a styrene-butadiene-styrene block copolymer or a hydrogenated product thereof is used. More preferred. Such a thermoplastic resin (A) can be synthesized by a method described in JP 2010-255007 A or International Publication No. 2007/126081.

  The content of the repeating unit derived from the aromatic vinyl compound in such a styrene-conjugated diene block copolymer is usually 5 to 40% by mass, preferably 10 to 35% by mass. When the content of the repeating unit derived from the aromatic vinyl compound is in the above range, the adhesive force can be further increased, and there is a tendency that no adhesive residue occurs due to cohesive failure.

  In the production of the pressure-sensitive adhesive film, when the substrate composition and the pressure-sensitive adhesive composition are co-extruded using a melt co-extrusion apparatus or the like, the component (A) contained in the pressure-sensitive adhesive composition The melt flow rate (MFR) measured at 230 ° C. and 21.2 N load is preferably 0.1 to 100 g / 10 minutes, more preferably 1.0 to 50 g / 10 minutes. It is particularly preferably 0 to 30 g / 10 minutes. If the MFR is less than 0.1 g / 10 minutes, the load during coextrusion may be excessive. On the other hand, if the MFR exceeds 100 g / 10 min, there is a tendency to cause problems in coextrusion moldability such as drawdown.

  The weight average molecular weight (Mw) of the component (A) is preferably 50,000 to 700,000, and more preferably 80,000 to 350,000. When the weight average molecular weight (Mw) of the component (A) is in the above range, an adhesive film excellent in molding processability and adhesive strength can be easily obtained. When this Mw is less than the above range, tackiness is excellent, but adhesive residue or the like may occur during peeling. If Mw exceeds the above range, the moldability or adhesive strength may not be sufficiently increased.

The component (A) preferably has at least one melting peak (crystal melting peak) in the range of 50 to 150 ° C. This melting peak temperature is measured by differential scanning calorimetry (DSC method). Specifically, using a differential scanning calorimeter (DSC), the sample component (A) was held at 200 ° C. for 10 minutes, then cooled to −80 ° C. at a rate of 10 ° C./minute, and then −80 This is the peak temperature of the heat flow rate (heat of crystal melting) when the temperature is raised at a rate of 10 ° C./min after being held at ° C. for 10 minutes. The crystal melting heat amount of the melting peak is in the range of 5 to 70 J / g, preferably 10 to 50 J / g.

1.1.2.2. Radical generator (B)
The radical generator (B) (hereinafter also simply referred to as “component (B)”) contained in the pressure-sensitive adhesive composition used in the present embodiment is used to produce a pressure-sensitive adhesive layer that constitutes a part of the pressure-sensitive adhesive film. In addition, it is used to generate radicals by heating or irradiating ultraviolet rays such as ultraviolet rays. By generating radicals to crosslink the component (A), it is possible to effectively reduce the adhesion progress of the formed adhesive layer.

  The component (B) is preferably a photoradical generator that generates radicals when irradiated with light such as ultraviolet rays. Specific examples of the photo radical generator include hydroxy ketones, benzyl dimethyl ketals, amino ketones, acyl phosphine oxides, benzophenones and the like. These photo radical generators can be used singly or in combination of two or more.

  The component (B) is particularly preferably an oligomer type photoradical generator. The oligomer type photo radical generator is a low molecular weight polymer of a monomer having a functional group capable of generating radicals by irradiation with light such as ultraviolet rays. Such an oligomer type photo radical generator has a plurality of radical generation points in one molecule, so it is not easily affected by cross-linking inhibition by oxygen and can be cross-linked with a small amount. In particular, it is preferably used because it does not scatter in a solvent-free hot melt state and is not extracted from the polymer.

  Specific examples of the oligomer type photo radical generator include oligomers obtained by polymerizing acrylated benzophenone (trade name “Ebecryl P36” manufactured by UCB), 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy- An oligomer obtained by polymerizing a reaction product of a primary hydroxyl group of 2-methyl-1-propan-1-one (trade name “Irgacure 2959” manufactured by BASF Corporation) and 2-isocyanatoethyl methacrylate, 2-hydroxy-2-methyl- [4 -(1-Methylvinyl) phenyl] propanol oligomer (manufactured by Lamberti, trade name “EsacureKIP150”) and the like. The molecular weight of these oligomer-type photoradical generators is preferably up to about 50,000.

  It is preferable that the content rate of the component (B) in the composition for adhesives used by this embodiment is 0.1 to 10 mass parts with respect to 100 mass parts of components (A), 0.5 It is more preferable that the amount is not less than 5 parts by mass.

1.1.2.3. Other components In the composition for pressure-sensitive adhesives according to the present embodiment, in addition to the above-described components, if necessary, other anti-blocking agents, tackifiers, anti-aging agents, fillers, polymers, colorants, You may add a flame retardant.

The anti-blocking agent is used to improve the productivity of the pressure-sensitive adhesive film by suppressing blocking (clogging) with a hopper or the like. As an anti-blocking agent, synthesis of fluoropolymers, polyethylene wax, polypropylene wax, ethylene-propylene copolymer wax, Fischer-Tropsch wax and their partial oxides or copolymers with ethylenically unsaturated carboxylic acids, etc. Hydrocarbon waxes; modified waxes such as montan wax derivatives, paraffin wax derivatives and microcrystalline wax derivatives; hydrogenated waxes such as hardened castor oil and hardened castor oil derivatives; higher fatty acids such as cetyl alcohol, stearic acid and 12-hydroxystearic acid; Alcohol: fatty acid ester such as glyceryl stearate, polyethylene glycol stearate, stearyl stearate, isopropyl palmitate; fatty acid amide such as stearic acid amide Calcium stearate, fatty acid metal salts of lithium stearate; phthalic anhydride imide, chlorinated hydrocarbons, and the like.

  Among these, at least one selected from the group consisting of polyethylene wax, polypropylene wax, fatty acid amide, fatty acid ester, and fatty acid metal salt is preferable. When an anti-blocking agent is added to the pressure-sensitive adhesive composition used in the present embodiment, blocking with a hopper or the like can be effectively suppressed in a production apparatus such as a melt coextrusion apparatus for producing a pressure-sensitive adhesive layer.

  As a method of adding the anti-blocking agent to the pressure-sensitive adhesive composition, the anti-blocking agent may be added to the pressure-sensitive adhesive composition and mixed and stirred uniformly, but the pressure-sensitive adhesive composition is formed into a pellet. When used, the anti-blocking agent may be unevenly distributed by, for example, applying to the pellet surface. When the blocking inhibitor is unevenly distributed on the pellet surface, blocking (clogging) of the hopper can be effectively suppressed when the pressure-sensitive adhesive film is produced by the co-extrusion method.

  It is preferable that the content rate of the antiblocking agent in the composition for adhesives used by this embodiment is 0.01 to 5 mass parts with respect to 100 mass parts of components (A), and 0.05 mass More preferably, it is 1 part by mass or more.

  The tackifier can be used, for example, for the purpose of further suppressing generation of an adhesive layer residue. The tackifier means a material that is compatible with the rubber layer that is a soft segment and can control the adhesive force. “Compatible” means that the tan δ peak temperature of the mixture obtained by adding a tackifier to the pressure-sensitive adhesive composition is different from the tan δ peak temperature of the pressure-sensitive adhesive composition. Say. In the present specification, “tan δ peak temperature” means a temperature at which tan δ is maximized.

  The tackifier is not particularly limited. For example, petroleum resins such as aliphatic copolymers, aromatic copolymers, aliphatic / aromatic copolymers, and alicyclic copolymers; coumarone-indene series Resins; terpene resins; terpene-phenol resins; rosin resins such as polymerized rosins; (alkyl) phenol resins; xylene resins; or hydrogenated products thereof, particularly those commonly used for adhesives Can be used without restriction. A tackifier having a softening point in the range of 90 to 140 ° C is preferable. Moreover, in order to improve peelability and weather resistance, it is preferable to use a hydrogenated type tackifier. These tackifiers may be used alone or in combination of two or more. Moreover, you may use the commercially available tackifier which is a mixture containing the above tackifiers in combination with an olefin resin.

  The content of the tackifier in the pressure-sensitive adhesive composition according to the present embodiment is preferably 1 part by mass or more and 50 parts by mass or less, and preferably 1 part by mass or more and 40 parts by mass with respect to 100 parts by mass of the component (A). The following is more preferable.

  As anti-aging agents, for example, antioxidants such as hindered phenols and phosphites, ultraviolet absorbers such as benzotriazoles, benzophenones and salicylates, and light stabilizers such as hindered amines are suitably added. . The addition amount of the anti-aging agent is preferably 10 parts by mass or less and more preferably 0.1 parts by mass or more and 1 part by mass or less with respect to 100 parts by mass of the component (A).

  As the filler, inorganic fillers such as talc, silica and calcium carbonate, and organic fillers such as carbon fiber and amide fiber can be used.

1.2. Laminated film preparation process Next, the laminated film which has a base material layer and an adhesion layer is produced by using the said composition for base materials and the said composition for adhesives using a coextrusion method. Specifically, the adhesive layer is bonded to at least one surface of the base material layer by coextrusion molding the base material composition and the adhesive composition using a melt coextrusion apparatus or the like. A laminated film is used. By using the coextrusion method, the production efficiency of the laminated film is greatly improved as compared with the case where other methods such as a coating method are used.

  As the melt coextrusion apparatus, any one having a plurality of extruders and having a feed block type or multi-layer type die can be used, and both a T die type and an inflation type can be used. .

1.3. Ultraviolet irradiation step Next, the adhesive layer of the laminated film obtained in the above step is irradiated with ultraviolet rays. After producing the laminated film by co-extrusion of the substrate composition and the pressure-sensitive adhesive composition by the co-extrusion method, the pressure-sensitive adhesive layer having a thickness of 5 to 200 μm is obtained by irradiating the pressure-sensitive adhesive layer with ultraviolet rays and crosslinking. Form.

The ultraviolet irradiation can be performed using an appropriate ultraviolet ray source such as a high-pressure mercury lamp, a low-pressure mercury lamp, an excimer laser, or a metal halide lamp. Dose of ultraviolet light is determined according to the degree of crosslinking in need, preferably ^{10mJ / cm 2 ~5000mJ / cm 2} , more preferably ^{100mJ / cm 2 ~5000mJ / cm 2} . In addition, a filter or a polyester sheet that cuts ultraviolet rays on the short wavelength side may be used as necessary. Furthermore, the temperature at the time of ultraviolet irradiation is not particularly limited, and heating conditions from room temperature to 140 ° C. can be appropriately selected.

  According to the above method for producing a pressure-sensitive adhesive film, a pressure-sensitive adhesive layer having improved pressure-sensitive adhesive properties and heat resistance can be produced by irradiating the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition with ultraviolet rays. Since fluidity is suppressed by partial crosslinking on the surface of the adhesive layer, the adhesion progress is particularly reduced among the adhesive properties. At that time, after the ultraviolet crosslinking, the solvent-soluble content of the block copolymer is 5 to 95% by mass, preferably 10 to 90% by mass. In order to obtain such a solvent-soluble component, the degree of crosslinking may be appropriately adjusted by selecting the amount of the radical generator (B) used or selecting the amount of ultraviolet irradiation.

  In place of the radical generator (B), when sulfur, a sulfur vulcanizing agent, or a vulcanization accelerator generally used for rubber crosslinking is used, a large amount of sulfide ions and sulfate ions are generated from the adhesive layer. Since it may bleed out, it is not preferable. In addition, it may be difficult to obtain sufficient heat resistance by crosslinking using a peroxide.

  The pressure-sensitive adhesive film thus produced can be used in a tape shape or a sheet shape as necessary.

2. EXAMPLES Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. “Part” and “%” in Examples and Comparative Examples are based on mass unless otherwise specified.

2.1. Example 1
2.1.1. Preparation of composition for pressure-sensitive adhesives Thermoplastic resin (A) (manufactured by JSR Corporation, product name “DR1320”, styrene-ethylene-butylene-styrene type thermoplastic elastomer) 100 parts by mass, radical generator (B) ( BASF Corporation, product name “Irgure 127”) 1 part by mass, calcium stearate (manufactured by Wako Pure Chemical Industries, Ltd.) 0.15 part by mass, and tackifier (Arakawa Chemical Industries, Ltd., product name “ARKONP-”) 125 ”) 30 parts by mass is melt-extruded and mixed in a twin-screw extruder (trade name“ Lab Blast Mill ”manufactured by Toyo Seiki Seisakusho), and the extruded strand is solidified in a hot tub set at 60 ° C. Was pelletized at a temperature of 5 mmφ to obtain a pressure-sensitive adhesive composition.

2.1.2. Manufacture of adhesive film Using polyethylene (Mitsubishi Chemical Co., Ltd., trade name “YF30”) as the base material layer, and the pellet-shaped adhesive composition prepared above as the adhesive layer, feed block type T-die With the two-layer coextrusion apparatus provided, the base material layer and the adhesive layer are formed under the molding conditions of a cylinder temperature of 190 ° C. and a die temperature of 190 ° C. so that the thickness of the base material layer becomes 100 μm and the thickness of the adhesive layer becomes 10 μm. Coextruded to produce a film. The pressure-sensitive adhesive layer surface of the obtained film was irradiated with an ultraviolet ray having an irradiation amount shown in Table 1 with a high-pressure mercury lamp to produce a pressure-sensitive adhesive film.

2.1.3. Evaluation method <Blocking evaluation in the hopper>
The obtained pellet of the pressure-sensitive adhesive composition was put into a two-layer coextrusion apparatus equipped with a feed block type T die, and the blocking state was confirmed in a hopper, and evaluated according to the following criteria. The results are shown in Table 1.
"3 points": Very good without blocking in the hopper.
-“2 points”: blocking in the hopper, but blocking with a stick breaks down.
・ "1 point": Blocking in the hopper, and sticking with a stick does not eliminate the blocking and is defective.

<Evaluation of initial adhesive strength>
A prism sheet (GTL5000) manufactured by Goyo Paper Industries Co., Ltd. was used as the adherend, and the adhesive layer of the adhesive film cut out to a width of 25 mm and the lens surface of the prism sheet were opposed to each other at room temperature (23 ° C. The pressure-sensitive adhesive film was pressure-bonded to the adherend with a 2 kg roller. Then, it is left to stand at 23 ° C. for 2 hours, and peeled off at 180 ° at a speed of 300 mm / min using a strograph (manufactured by Toyo Seiki Seisakusho, model number “VES05D”) in an environment of 23 ° C. and 60% RH. The initial adhesive strength was measured. The larger the value of the initial adhesive strength, the better. However, practically, when the value is 50 mN / 25 mm or more, it can be judged as good.

<Evaluation of advancing magnification>
A prism sheet (GTL5000) manufactured by Goyo Paper Industries Co., Ltd. was used as the adherend, and the adhesive layer of the adhesive film cut out to a width of 25 mm and the lens surface of the prism sheet were opposed to each other at room temperature (23 ° C. The pressure-sensitive adhesive film was pressure-bonded to the adherend with a 2 kg roller. After that, it was left to stand at 60 ° C. for 20 hours, and peeled off by 180 ° at a speed of 300 mm / min using a strograph (manufactured by Toyo Seiki Seisakusho, model number “VES05D”) in an environment of 23 ° C. and 60% RH. The force was measured.
Using the values of the initial adhesive strength and the progressive adhesive strength, the forward magnification was calculated from the following formula.
-Progression magnification = Progressive adhesive force / Initial adhesive force The smaller the value, the better the progress magnification. However, when it is practically 2.0 or less, it can be judged as good.

<Evaluation of adhesive residue>
The surface state of the adherend after evaluating the progressive adhesive strength was visually confirmed, the state of the adherend surface was confirmed, and evaluation was performed according to the following indices.
-“3 points”: Very good because no adhesive remains.
・ “2 points”: Good because a slight adhesive residue is observed.
・ "1 point": A large amount of adhesive remains and is defective.

2.2. Examples 2-8, 10-21, Comparative Examples 1-2
Except having set it as the composition and manufacturing conditions of Tables 1-3, it carried out similarly to Example 1, and manufactured the composition for adhesives and an adhesive film, and evaluated. The results are shown in Tables 1 to 3.

2.3. Example 9
Thermoplastic resin (A) (manufactured by JSR Corporation, product name “DR1320”, 100 parts by mass of styrene-ethylene-butylene-styrene type thermoplastic elastomer), radical generator (B) (manufactured by BASF, product name “ 1 part by weight, and 30 parts by weight of a tackifier (manufactured by Arakawa Chemical Co., Ltd., product name “ARKONP-125”), a twin-screw extruder (manufactured by Toyo Seiki Seisakusho, trade name “Lab Blast Mill”) The extruded strand was solidified in a hot bath set at 60 ° C. and pelletized with a strand cutter to obtain 5 mmφ pellets. 0.08 parts by mass of calcium stearate (manufactured by Wako Pure Chemical Industries, Ltd.) was added as an antiblocking agent to the total amount of pellets obtained, and the antiblocking agent was unevenly distributed on the pellet surface by mixing and stirring. A pellet-shaped composition for pressure-sensitive adhesives was obtained.

  A pressure-sensitive adhesive film was produced and evaluated in the same manner as in Example 1 except that the pellet-shaped pressure-sensitive adhesive composition thus obtained was used. The results are shown in Table 1.

2.4. Comparative Example 3
Except having set it as the composition of Table 2, it carried out similarly to Example 1, and obtained the pellet-shaped composition for adhesives. The obtained pellet-shaped pressure-sensitive adhesive composition was dissolved in toluene so as to have a pellet weight fraction of 17% to prepare a pressure-sensitive adhesive composition coating solution.

  Using polyethylene (Mitsubishi Chemical Co., Ltd., YF30) as a base material layer, a base material layer having a thickness of 100 μm was produced by an extrusion apparatus equipped with a feed block type T die, and the adhesive layer was formed with a doctor blade. The pressure-sensitive adhesive composition coating solution was applied so as to have a thickness of 10 μm, then dried at 25 ° C. for 20 hours and further dried at 70 ° C. for 1 hour to form an adhesive layer to obtain a film. The pressure-sensitive adhesive layer surface of the obtained film was irradiated with an irradiation amount of ultraviolet rays shown in Table 2 with a high-pressure mercury lamp to produce a pressure-sensitive adhesive film. The obtained adhesive film was evaluated in the same manner as in Example 1. The results are shown in Table 2.

2.5. Evaluation results Tables 1 to 3 below show the compositions of the pressure-sensitive adhesive compositions used in the examples and comparative examples, the production conditions of the pressure-sensitive adhesive film, and the evaluation results.

In Tables 1 to 3, the abbreviations of the components are as follows.
<Thermoplastic resin (A)>
DR1320 (manufactured by JSR Corporation, product name “DR1320”, styrene-ethylene-butylene-styrene type thermoplastic elastomer)
-TR2827 (manufactured by JSR Corporation, product name "TR2827", styrene-butadiene-styrene type thermoplastic elastomer)
RB810 (manufactured by JSR Corporation, product name “RB810”, syndiotactic polybutadiene type thermoplastic elastomer)
SIS 5229 (manufactured by JSR Corporation, product name “SIS 5229”, styrene-isoprene-styrene type thermoplastic elastomer)
<Radical generator (B)>
・ Irg127 (manufactured by BASF, product name “Irgacure127”, 10% weight reduction temperature 290 ° C.)
・ KIP150 (Lamberti, product name “EsacureKIP150”, heat-resistant temperature 255 ° C.)
・ Irg 369 (manufactured by BASF, product name “Irgacure 369”, 10% weight reduction temperature 264 ° C.)
・ Irg907 (manufactured by BASF, product name “Irgacure907”, 10% weight reduction temperature 214 ° C.)
・ Irg184 (manufactured by BASF, product name “Irgacure184”, 10% weight reduction temperature 170 ° C.)
<Ingredient (C)>
・ Ca stearate (Wako Pure Chemical Industries, Ltd., calcium stearate)
・ Lithium stearate (Wako Pure Chemical Industries, Ltd.)
・ Stearic acid amide (Wako Pure Chemical Industries, Ltd.)
・ Polyethylene wax (Mitsui Chemicals, product name “High Wax 200P”)
・ Polypropylene wax (product name “High Wax NP055” manufactured by Mitsui Chemicals, Inc.)

  The measurement of the 10% weight reduction temperature of the radical generator (B) was made from the initial weight when the temperature was increased from 35 ° C. at a rate of 10 ° C./min using NETZSCH (model number: TG-DTA2000SR). This was done by reading the temperature when the 10% weight was reduced.

  According to Examples 1 to 21, the pressure-sensitive adhesive composition according to the present invention has a high adhesive force to the adherend, a low adhesion progress, and a balance of adhesive properties such that there is no adhesive residue on the adherend. It was possible to produce an adhesive film having an excellent adhesive layer. When Examples 1-21 and Comparative Examples 1-2 were contrasted, it was found that in Examples 1-21, the adhesion progress was significantly reduced.

  Further, when Example 8 and Example 9 were compared, it was found that blocking in the hopper was more effectively suppressed when the blocking inhibitor was unevenly distributed on the surface of the pellet-shaped adhesive composition. .

  Furthermore, when Example 5 was compared with Comparative Example 3, it was found that the adhesive film produced by the coextrusion method had less adhesive residue than the adhesive film produced by the coating method. The reason for this is presumed that in the coating method, the interface area between the base material layer and the adhesive layer was reduced, and the adhesive layer was distorted by curing shrinkage, resulting in distortion between the coated surface and the cured adhesive layer. Is done.

  The present invention is not limited to the above embodiment, and various modifications can be made. The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). The present invention also includes a configuration in which a non-essential part of the configuration described in the above embodiment is replaced with another configuration. Furthermore, the present invention includes a configuration that achieves the same effects as the configuration described in the above embodiment or a configuration that can achieve the same object. Furthermore, the present invention includes a configuration obtained by adding a known technique to the configuration described in the above embodiment.

Claims (4)

A step of preparing a composition for a substrate and a composition for an adhesive containing a thermoplastic resin (A) and a radical generator (B);
Producing a laminated film having a base material layer and an adhesive layer using a co-extrusion method of the base material composition and the adhesive composition;
Irradiating the adhesive layer of the laminated film with ultraviolet rays;
Only including,
The manufacturing method of the adhesive film whose 100 mass% of the said thermoplastic resin (A) is a thermoplastic elastomer .   The method for producing an adhesive film according to claim 1, wherein the thermoplastic resin (A) has a repeating unit derived from a conjugated diene compound and a repeating unit derived from an aromatic vinyl compound.   The said composition for adhesives contains the said radical generating agent (B) 0.1 mass part or more and 10 mass parts or less with respect to 100 mass parts of said thermoplastic resins (A). The manufacturing method of the adhesive film of description. The manufacturing method of the adhesive film as described in any one of Claim 1 thru | or 3 whose irradiation amount of the said ultraviolet-ray is 10-5000mJ / cm < ² >.