JP2007211135A - Pressure-sensitive adhesive film and use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive film having moderate pressure-sensitive adhesiveness and adhesiveness to an adherend surface and scarcely causing a remaining paste of a pressure-sensitive adhesive layer when the pressure-sensitive adhesive layer is peeled and removed even after preservation over a long period. <P>SOLUTION: The pressure-sensitive adhesive film is obtained by forming the pressure-sensitive adhesive layer comprising a polyolefin resin (A) on a resin film. The polyolefin resin (A) contains 0.01-7 mass% of an unsaturated carboxylic acid component and 28-45 mass% of an acrylic or a methacrylic ester component. The amount of the pressure-sensitive adhesive layer is 0.01-5 g/m<SP>2</SP>. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an adhesive film. More specifically, functional treatment (such as rust prevention treatment in the case of metal) on the surface of a synthetic resin plate, synthetic resin film, synthetic paper, metal plate, decorative plywood, liquid crystal plate, glass plate, or their base material. In the case of resin base materials, corona treatment, various vapor deposition treatments, various barrier treatments, easy adhesion treatments, treatments for providing UV photoreceptors and various receiving layers, and in the case of glass, water repellent treatment, etc.) The present invention relates to an adhesive film suitable as a surface protective film used for preventing adhesion and scratching.

  Conventionally, these surfaces are used during processing or transporting (before use) of synthetic resin plates, synthetic resin films, synthetic paper, metal plates, decorative plywood, liquid crystal plates, glass plates, etc. (hereinafter referred to as “adhesives”). Surface protective films are widely used to prevent dirt from being attached to or scratched on the surface. The surface protective film is one in which an adhesive layer is formed on one side of a base material layer made of thermoplastic resin, paper, or the like. While the adherend is processed and transported, the surface protective film is temporarily attached to the adherend surface by the pressure-sensitive adhesive layer to cover the adherend surface, thereby preventing adhesion and scratching of the adherend.

  The surface protective film is peeled off from the surface of the adherend when the adherend is used for its original application. Therefore, the surface protective film has an appropriate tackiness that can be easily temporarily attached to the adherend surface, and requires good peelability that can be easily peeled off from the adherend surface after use, and It is required that no adhesive remains on the adherend surface after peeling.

  In order to satisfy the above requirements, for example, Patent Document 1 discloses that a random copolymer hydrogenated product composed of 1 to 50% by weight of styrene and 99 to 50% by weight of a diene hydrocarbon and 40% by weight of polyolefin. % (A) layer having a composition of not more than 50%, a hydrogenated random copolymer consisting of 1 to 50% by weight of styrene and 99 to 50% by weight of a diene hydrocarbon and less than 60% by weight of polyolefin A surface protective film in which the layer (B) having the composition is laminated and integrated by coextrusion is disclosed.

Japanese Patent Laid-Open No. 7-241960

  However, according to the composition of the layer (A) corresponding to the pressure-sensitive adhesive layer of the surface protective film described in Patent Document 1, adhesion progress occurs after being temporarily attached to the adherend, and the surface of the adherend is removed when peeling off. It is easy for a part of the pressure-sensitive adhesive to remain (hereinafter referred to as “glue residue”). In particular, when stored at about 40 ° C., adhesive residue tends to occur. As a result, there is a problem that the commercial value is reduced or lost.

  The present invention has appropriate tackiness and adhesiveness to the adherend surface with respect to the above-mentioned problems, and the adhesive layer hardly retains adhesive when it is peeled off after long-term storage. An attempt is made to provide an adhesive film.

As a result of diligent research, the present inventors have found that a film provided with a specific amount of an adhesive layer containing a polyolefin resin having a specific composition on at least one surface of a thermoplastic resin film has an appropriate adhesiveness and adhesion to the adherend surface. In addition, the present inventors have found that the adhesive layer hardly causes adhesive residue when peeling and removing even after long-term storage.
That is, the gist of the present invention is as follows.

[1] Adhesion in which an adhesive layer containing a polyolefin resin (A) containing 0.01 to 7% by mass of an unsaturated carboxylic acid component and 28 to 45% by mass of a (meth) acrylic acid ester component is provided on a resin film. It is a film, Comprising: The quantity of this adhesion layer is 0.01-5 g / m < ² >, The adhesion film characterized by the above-mentioned.
[2] The adhesive layer further contains a polyolefin resin (A ^* ) containing 0.01 to 7% by mass of an unsaturated carboxylic acid component and 0 to 12% by mass of a (meth) acrylic acid ester component. The adhesive film according to [1].
[3] The adhesive layer further contains a water-soluble polymer compound having a number average molecular weight of 10,000 or more, and this content is 0 with respect to 100 parts by mass in total of the polyolefin resins (A) and (A ^* ). The pressure-sensitive adhesive film according to [1] or [2], which is 1 to 30 parts by mass.
[4] The adhesive film according to any one of [1] to [3], wherein the resin film is a polyolefin resin film.
[5] The adhesive film according to any one of [1] to [4], which is a film used as a protective film.
[6] The method for producing an adhesive film as described in any one of [1] to [5], wherein an aqueous dispersion containing a polyolefin resin is applied to the surface of the resin film, and then the aqueous medium is dried.

  The pressure-sensitive adhesive film of the present invention has appropriate pressure-sensitive adhesiveness and adhesiveness to various adherend surfaces, and it is difficult for adhesive residue to remain in the pressure-sensitive adhesive layer when peeling and removing even after long-term storage. In addition, there is an advantage that the dependency on the application amount of the tackiness and adhesiveness is reduced, and the performance is easily stabilized. Therefore, the adhesive film of the present invention can be suitably used as a protective film for protecting various adherend surfaces.

  Hereinafter, the present invention will be described in detail.

The pressure-sensitive adhesive film of the present invention is obtained by providing a pressure-sensitive adhesive layer containing a polyolefin resin on a resin film, and the coating amount of this pressure-sensitive adhesive layer is 0.01 to 5 g / m ^2. It contains substantially no emulsifier component with a number average molecular weight of 10,000 or less.

Coating amount of the adhesive layer, moderate tack, from the viewpoint of the adhesive property can be imparted, must be 0.01-5 g / ^{m 2,} it is preferably 0.02~2g / ^{m 2,} 0 more preferably .05~2g / ^{m 2,} more preferably from 0.05 to 1 g / ^{m 2,} and particularly preferably 0.1 to 1 g / ^{m 2.} When the coating amount is less than 0.01 g / m ² , the tackiness and adhesiveness tend to be lowered and the performance as an adhesive film tends to be lost, and when it is more than 5 g / m ² , the adhesive residue tends to remain. .

  The polyolefin resin (A) contained in the adhesive layer needs to contain 0.01 to 7% by mass of an unsaturated carboxylic acid component. The content of the unsaturated carboxylic acid component is preferably 0.1 to 5% by mass, more preferably 1 to 4% by mass. When the content of the unsaturated carboxylic acid component is less than 0.01% by mass, it becomes difficult to make the resin aqueous (liquefied), and it becomes difficult to laminate the adhesive layer of the present invention to a predetermined thickness. If it exceeds 7% by mass, the adhesion to the polyolefin substrate may be lowered.

  The unsaturated carboxylic acid component of the polyolefin resin (A) is introduced by an unsaturated carboxylic acid or its anhydride. Specifically, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride In addition to fumaric acid, crotonic acid and the like, unsaturated dicarboxylic acid half ester, half amide and the like can be mentioned. Of these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferable, and acrylic acid and maleic anhydride are particularly preferable. Further, the unsaturated carboxylic acid component may be copolymerized in the polyolefin resin (A), and the form thereof is not limited. For example, random copolymerization, block copolymerization, graft copolymerization (graft modification), etc. Can be mentioned.

  The polyolefin resin (A) needs to contain 28 to 45% by mass of the (meth) acrylic acid ester component, preferably 28 to 40% by mass, and more preferably 28 to 38% by mass. When the content of this component is less than 28% by mass, it becomes difficult to impart appropriate tackiness, and when it is 45% by mass or more, the adhesion with the resin film substrate may be reduced. is there.

  Examples of the (meth) acrylic acid ester component include an esterified product of (meth) acrylic acid and an alcohol having 1 to 30 carbon atoms, and (meth) acrylic acid and carbon number 1 from the viewpoint of easy availability. Esterified products with ˜20 alcohols are preferred. Specific examples of such compounds include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, (meth) acrylic acid. Examples include octyl, decyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, and the like. Mixtures of these may be used. Of these, methyl (meth) acrylate (ethyl) (meth) acrylate, butyl (meth) acrylate, hexyl acrylate, and octyl acrylate are more preferable from the viewpoint of adhesion to various substrates, and ethyl acrylate. More preferred is butyl acrylate, and particularly preferred is ethyl acrylate. ("(Meth) acrylic acid" means "acrylic acid or methacrylic acid".)

  The olefin component of the polyolefin resin (A) is not particularly limited, but alkene having 2 to 6 carbon atoms such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, 1-hexene is preferable, and a mixture thereof. May be used. Among these, alkenes having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and 1-butene are more preferable, and ethylene and propylene are more preferable.

  As a specific example of the polyolefin resin (A), an ethylene- (meth) acrylic acid ester-maleic anhydride copolymer is most preferable. The form of the copolymer may be any of a random copolymer, a block copolymer, a graft copolymer, etc., but a random copolymer and a graft copolymer are preferred from the viewpoint of easy availability.

  Further, the polyolefin resin (A) may be chlorinated, and in this case, the chlorination rate is suitably 5 to 50% by mass. The method for chlorination is not particularly limited, and a known method can be used. For example, it can be carried out by dissolving a resin to be chlorinated in a chlorine-based solvent such as chloroform and then blowing gaseous chlorine while irradiating with ultraviolet rays or in the presence of a radical generator.

  In the present invention, the polyolefin resin (A) preferably has a melt flow rate of 0.01 to 1000 g / 10 minutes at 190 ° C. and a load of 2160 g, which is a measure of molecular weight, and more preferably 0.01 to 100 g / 10. Minutes. Among these, 0.01 to 30 g / 10 min is more preferable from the viewpoint that the adhesive residue after the storage for a period is less likely to occur and the coating amount dependency of adhesiveness and adhesiveness is reduced and the performance is easily stabilized. 0.1-10 g / 10 min is particularly preferred. When the melt flow rate is less than 0.01 g / 10 minutes, the adhesion with the substrate tends to be lowered. On the other hand, when the melt flow rate of the polyolefin resin exceeds 1000 g / 10 minutes, the coating film becomes hard and brittle, and the adhesion to the substrate is lowered.

In the present invention, it is preferable that the adhesive layer further contains a polyolefin resin (A ^* ) from the viewpoint of reducing adhesive residue when peeled after long-term storage.

The polyolefin resin (A ^* ) needs to contain 0.01 to 7% by mass of an unsaturated carboxylic acid component, preferably 0.1 to 5% by mass, and more preferably 1 to 4% by mass. When the content of this component is less than 0.01% by mass, it becomes difficult to make the resin aqueous (liquefied), and it becomes difficult to make the adhesive layer have a predetermined coating amount, while 7% by mass. When it exceeds%, the adhesion to the resin substrate may be lowered.

The unsaturated carboxylic acid component of the polyolefin resin (A ^* ) is introduced by an unsaturated carboxylic acid or its anhydride. Specifically, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride In addition to acids, fumaric acid, crotonic acid and the like, unsaturated dicarboxylic acid half esters, half amides and the like can be mentioned. Of these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferable, and acrylic acid and maleic anhydride are particularly preferable. The unsaturated carboxylic acid component may be copolymerized in the polyolefin resin (A ^* ), and the form thereof is not limited. For example, random copolymerization, block copolymerization, graft copolymerization (graft modification), etc. Is mentioned.

(Meth) acrylic acid ester is added to the polyolefin resin (A ^* ) to give appropriate tackiness when mixed with the polyolefin resin (A), and to reduce adhesive residue after long-term storage and storage under heat. Ingredients may be contained. The content of the (meth) acrylic acid ester component is preferably 0 to 12% by mass, more preferably 1 to 10% by mass, and more preferably 2 to 8% by mass. Yes. (A3) When content of a component is 12 mass% or more, it becomes difficult to remove.

Examples of the (meth) acrylic acid ester component of the polyolefin resin (A ^* ) include an esterified product of (meth) acrylic acid and an alcohol having 1 to 30 carbon atoms. ) An esterified product of acrylic acid and an alcohol having 1 to 20 carbon atoms is preferred. Specific examples of such compounds include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, (meth) acrylic acid. Examples include octyl, decyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, and the like. Mixtures of these may be used. Of these, methyl (meth) acrylate (ethyl) (meth) acrylate, butyl (meth) acrylate, hexyl acrylate, and octyl acrylate are more preferable from the viewpoint of adhesion to various substrates, and ethyl acrylate. More preferred is butyl acrylate, and particularly preferred is ethyl acrylate.

The olefin component of the polyolefin resin (A ^* ) is not particularly limited, but alkene having 2 to 6 carbon atoms such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, 1-hexene is preferable. Mixtures may be used. Among these, as (A2), C2-C4 alkenes, such as ethylene, propylene, isobutylene, 1-butene, are more preferable, and ethylene and propylene are further more preferable.

As a specific example of the polyolefin resin (A ^* ), an ethylene- (meth) acrylic acid ester-maleic anhydride copolymer is most preferable. The form of the copolymer may be any of a random copolymer, a block copolymer, a graft copolymer, etc., but a random copolymer and a graft copolymer are preferred from the viewpoint of easy availability.

The polyolefin resin (A ^*) and the polyolefin resin (A) in the case of using the (A ^*) the weight ratio of (A) / (A ^*) is moderate tack, point adhesion can be imparted and long-term storage or after heat From the point of reducing adhesive residue at the time of lower storage, it is preferably 5/95 to 95/5, more preferably 10/90 to 80/20, and 15/85 to 70/30. Further preferred is 20/80 to 60/40.

The polyolefin resin (A ^* ) may be chlorinated. In this case, the chlorination rate is suitably 5 to 50% by mass. The method for chlorination is not particularly limited, and a known method can be used. For example, it can be carried out by dissolving a resin to be chlorinated in a chlorine-based solvent such as chloroform and then blowing gaseous chlorine while irradiating with ultraviolet rays or in the presence of a radical generator.

The polyolefin resin (A ^* ) preferably has a melt flow rate of 0.01 to 1000 g / 10 minutes, more preferably 0.01 to 100 g / 10 minutes at 190 ° C. and 2160 g load, which is a measure of molecular weight. . Among these, 0.01 to 30 g / 10 min is more preferable from the viewpoint that the adhesive residue after the storage for a period is less likely to occur and the coating amount dependency of adhesiveness and adhesiveness is reduced and the performance is easily stabilized. 0.1-10 g / 10 min is particularly preferred. When the melt flow rate is less than 0.01 g / 10 minutes, the adhesion with the substrate tends to be lowered. On the other hand, when the melt flow rate of the polyolefin resin exceeds 1000 g / 10 minutes, the coating film becomes hard and brittle, and the adhesion to the substrate is lowered.

In the polyolefin resin (A) and the polyolefin resin (A ^* ), the following components may be contained in each resin up to 25% by mass. Namely, alkenes having 6 or more carbon atoms such as 1-octene and norbornenes, dienes such as butadiene and isoprene, maleic esters such as dimethyl maleate, diethyl maleate and dibutyl maleate, (meth) acrylic amide , Saponification of vinyl esters such as methyl vinyl ether, alkyl vinyl ethers such as ethyl vinyl ether, vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl versatate and vinyl esters with basic compounds, etc. Vinyl alcohol, 2-hydroxyethyl acrylate, glycidyl (meth) acrylate, (meth) acrylonitrile, styrene, substituted styrene, halogenated vinyls, vinylidene halides, carbon monoxide, sulfur dioxide, etc. It may be a mixture of et al. These components may be copolymerized with each polyolefin resin, and the form thereof is not particularly limited, and examples thereof include random copolymerization, block copolymerization, and graft copolymerization (graft modification).

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film preferably contains a water-soluble polymer having a number average molecular weight of 10,000 or more for the purpose of reducing the change with time of the pressure-sensitive adhesive. The number average molecular weight is preferably 20,000 or more, more preferably 30,000 to 5,000,000, still more preferably 30,000 to 2,000,000, and particularly preferably 40,000 to 1,000,000, from the viewpoint that adhesive residue of the adhesive layer hardly occurs. Examples of the water-soluble polymer include modified polyvinyl alcohol such as polyvinyl alcohol and carboxyl group-modified polyvinyl alcohol, polyalkylene oxide, polyethyleneimine, polyallylamine, cellulose compounds such as carboxymethylcellulose and hydroxyethylcellulose, starch, modified starch, guar gum, Polysaccharides such as carrageenan, alginate, polyvinyl pyrrolidone, polyoxyethylene, polyvinyl methyl ether, polyoxazoline, poly (meth) acrylic acid and its salt, acrylic acid-maleic anhydride copolymer and its salt, styrene- (meta ) Acrylic acid copolymer and salt thereof, ethylene- (meth) acrylic acid copolymer and salt thereof, methyl vinyl ether-maleic anhydride alternating copolymer and salt thereof Isobutylene-maleic anhydride alternating copolymer and salt thereof, polyitaconic acid and salt thereof, polymaleic acid and salt thereof, water-soluble acrylic copolymer having amino group such as polyacrylamide, dextrin, gelatin, gum arabic, casein, Collagen etc. can be mentioned. You may use these in mixture of 2 or more types. Of these, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl pyrrolidone, and polyoxyethylene are preferable from the viewpoint of the stability of the aqueous dispersion and the transparency of the coating film, and polyvinyl alcohol and ethylene-vinyl alcohol copolymer are particularly preferable. preferable. The saponification degree of polyvinyl alcohol is preferably 80 to 100% from the viewpoint of easy handling as an aqueous solution. The content of the water-soluble polymer is preferably 0.1 to 30 parts by mass with respect to a total of 100 parts by mass of the polyolefin resins (A) and (A ^* ), from the viewpoint that appropriate tackiness can be imparted. 1 to 28 parts by mass is more preferable, 2 to 25 parts by mass is further preferable, and 5 to 25 parts by mass is particularly preferable.

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film may contain another polymer as long as the effects of the present invention are not impaired. Other polymers are not particularly limited. For example, polyolefin resins other than those mentioned above, polyvinyl chloride, polyvinylidene chloride, styrene-maleic acid resin, styrene- (meth) acrylic acid resin, styrene-butadiene resin, butadiene resin, acrylonitrile-butadiene resin, poly (meth) Examples include acrylonitrile resin, (meth) acrylamide resin, polyester resin, modified nylon resin, urethane resin, acrylic resin, phenol resin, silicone resin, and epoxy resin. You may use these in mixture of 2 or more types. The addition amount of the other polymer is usually 1 to 50 parts by mass with respect to 100 parts by mass in total of the polyolefin resins (A) and (A ^* ).

A cross-linking agent may be added to the pressure-sensitive adhesive layer in order to further improve various coating film performances such as a balance between tackiness and adhesiveness, water resistance and solvent resistance of the coating film. In this case, 0.01 to 30 parts by mass, preferably 0.1 to 20 parts by mass can be added to 100 parts by mass in total of the polyolefin resins (A) and (A ^* ). When the addition amount of the crosslinking agent is less than 0.01 parts by mass, the degree of improvement in the coating film performance is small, and when it exceeds 30 parts by mass, the adhesive performance may be deteriorated. As the crosslinking agent, a crosslinking agent having self-crosslinking property, a compound having a plurality of functional groups that react with a carboxyl group in the molecule, a metal complex having a polyvalent coordination site, etc. can be used. Of these, isocyanate compounds , Melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, oxazoline group-containing compounds, zirconium salt compounds, silane coupling agents and the like are preferable. Moreover, you may use combining these crosslinking agents.

  For the adhesive layer, various agents such as leveling agents, antifoaming agents, anti-waxing agents, antistatic agents, pigment dispersants, UV absorbers, and pigments or dyes such as titanium oxide, zinc white, and carbon black are used as necessary. May be added.

  In the case of using an emulsifier component having a number average molecular weight of less than 10,000, the amount added is 2 parts by mass or less with respect to 100 parts by mass of the polyolefin resin component. Preferably, it is 1 part by mass or less. However, it is particularly preferable that an emulsifier having a number average molecular weight of less than 10,000 is not used and is not substantially contained in the adhesive layer.

  Examples of the emulsifier component used in the present invention include cationic emulsifiers, anionic emulsifiers, nonionic emulsifiers, and amphoteric emulsifiers. In addition to those generally used for emulsion polymerization, surfactants are also included. For example, anionic emulsifiers include higher alcohol sulfates, higher alkyl sulfonates, higher carboxylates, alkyl benzene sulfonates, polyoxyethylene alkyl sulfate salts, polyoxyethylene alkyl phenyl ether sulfate salts, vinyl sulfosuccinates. Nonionic emulsifiers include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyethylene glycol fatty acid ester, ethylene oxide propylene oxide block copolymer, polyoxyethylene fatty acid amide, ethylene oxide-propylene oxide. Compounds having a polyoxyethylene structure such as copolymers and sorbitan derivatives such as polyoxyethylene sorbitan fatty acid esters And examples of the amphoteric emulsifiers, lauryl betaine, lauryl dimethyl amine oxide, and the like.

  As the base resin film of the pressure-sensitive adhesive film of the present invention, polyethylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate and other polyester resins, polyglycolic acid and polylactic acid Biodegradable resins represented by aliphatic polyester resins such as polyhydroxycarboxylic acid such as poly (ethylene succinate) and poly (butylene succinate), polyamide resins such as nylon 6, nylon 66, nylon 46, PP, Polyethylene, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid ester copolymer, ionomer, ethylene-propylene copolymer, ethylene-propylene-butene copolymer, propylene-butene copolymer And films made of polyolefin resins, rubber resins, polyimide resins, polyarylate resins or mixtures thereof, such as coalesced and modified products thereof (acid-modified, chlorinated products), polyester resins, polyamide resins, polyethylene, ethylene- Each film such as a vinyl acetate copolymer, an ionomer, a polyolefin resin such as PP, or a rubber resin is more preferable, and a polyolefin resin film is particularly preferable. Examples of the rubber-based resin include polybutadiene, polychloroprene, natural rubber, styrene-acrylonitrile rubber, and styrene-butadiene rubber.

  The resin film may be an unstretched film or a stretched film, and its production method is not particularly limited. Moreover, the laminated body which consists of a some layer may be sufficient as a film. Although the thickness is not particularly limited, it is usually in the range of 1 to 500 μm. The thermoplastic resin film may be subjected to surface treatment such as corona treatment or plasma treatment.

  Silica, alumina, or the like may be deposited on the resin film, or a gas barrier coat layer such as an oxygen gas barrier layer may be laminated.

  The method of providing the adhesive layer on the resin film is not particularly limited, but a method of co-extruding the resin film and the adhesive layer by an inflation method, a T-die method, or the like, or a coating agent in which an adhesive layer component is dissolved or dispersed in the resin film A method of applying and drying the medium, a method of applying a coating agent in which the adhesive layer component is dissolved or dispersed on the release paper, and a method of transferring the adhesive layer after drying the medium to a resin film. Examples thereof include a method of melt extrusion to a resin film. Above all, from the viewpoint of environment and performance, a method of applying a coating agent (aqueous dispersion) in which a polyolefin resin as an adhesive layer component is dissolved or dispersed in an aqueous dispersion and drying the medium on the resin film surface However, it is preferable because it is easy to adjust the amount of the adhesive layer, and in particular, it is easy to control the thickness thinly. An aqueous dispersion suitable for forming such an adhesive layer and a method for producing the same are described in, for example, Japanese Patent No. 3699935.

  In the case of using an aqueous dispersion, known application methods such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dip coating, and brush coating are used. Apply a uniform coating on the surface of the thermoplastic resin film, etc., and set it at around room temperature as necessary, followed by heat treatment for drying or drying, so that the uniform adhesive layer adheres to the surface of various substrates. Can be formed.

  Moreover, you may perform what is called in-line coating which extends | stretches a film, after apply | coating an aqueous dispersion to an unstretched film.

  The pressure-sensitive adhesive film of the present invention has moderate pressure-sensitive adhesiveness and adhesion to the adherend surface, and the adhesive layer hardly adheres to the surface of the adherend when it is peeled off after long-term storage. It is suitable as a protective film. As the adherend, functional treatment (such as rust prevention treatment in the case of metal) on the surface of a synthetic resin plate, synthetic resin film, synthetic paper, metal plate, decorative plywood, liquid crystal plate, glass plate, etc. In the case of a synthetic resin base material, a corona treatment, various vapor deposition treatments, various barrier treatments, an easy adhesion treatment, a treatment for providing a UV photosensitive member and various receiving layers, and in the case of glass a water repellent treatment, etc. It is done.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

  Various characteristics were measured or evaluated by the following methods.

1. Resin Characteristics (1) Configuration of Polyolefin Resin Configurations other than the unsaturated carboxylic acid component were determined from ¹ H-NMR analysis (manufactured by Varian, 300 MHz). Orthodichlorobenzene (d4) was used as a solvent, and measurement was performed at 120 ° C. The unsaturated carboxylic acid content was calculated from the value obtained by measuring the acid value of the resin according to JIS K5407.
(2) Melt flow rate (MFR)
It measured by the method of JIS6730 description (190 degreeC, 2160g load).

2. Characteristics of Aqueous Dispersion (1) Solid Concentration of Aqueous Dispersion An appropriate amount of the aqueous dispersion was weighed and heated at 150 ° C. until the mass of the residue (solid content) reached a constant weight to determine the solid content concentration. .
(2) Average particle diameter of aqueous dispersion The number average particle diameter (mn) and the weight average particle diameter (mw) using a Microtrac particle size distribution analyzer UPA150 (MODEL No. 9340, dynamic light scattering method) manufactured by Nikkiso Co., Ltd. ) Here, the refractive index of the resin used for calculating the particle diameter was set to 1.50.

3. Material characteristics In the following evaluation, as a thermoplastic resin film, a biaxially stretched polyethylene terephthalate film (Embret PET12 manufactured by Unitika, thickness 12 μm, hereinafter referred to as PET), a stretched polypropylene film (OP U-1, manufactured by Tosero Co., Ltd., thickness 50 μm). Hereinafter, PP) was used.

(1) Water resistance evaluation method of coating film After coating the aqueous dispersion on the corona-treated surface of the OPP film using a Mayer bar so that the coating amount of the adhesive layer after drying is 2 g / m ² , 1 at 90 ° C. Allow to dry for a minute. The obtained coated film was evaluated after standing at room temperature for 1 day. The coating film was rubbed 10 times with a cloth wetted with water, and the state of the coating film was visually evaluated.
○: No change, △: Cloudy coating, ×: Coating peels off or completely dissolves

(2) Adhesiveness of coating film After coating the aqueous dispersion on various substrates using a Mayer bar so that the coating amount of the adhesive layer after drying was 2 g / m ² , the coating was dried at 90 ° C. for 1 minute. . The obtained laminate was allowed to stand at room temperature for 1 day, and then a cellophane tape (TF-12 manufactured by Nichiban Co., Ltd.) was attached to the surface, and the degree of peeling when the tape was peeled at a stretch was visually evaluated.
○: No peeling at all, Δ: Partial peeling off, ×: All peeling off

(3) Transparency of coating film According to JIS K7105, "Haze (%)" was measured using NDH2000 "turbidity, haze meter" manufactured by Nippon Denshoku Industries Co., Ltd. After coating the aqueous dispersion using a Mayer bar on a PET film having a haze of 2.8% (Embret PET12 manufactured by Unitika, thickness 12 μm) so that the coating amount of the adhesive layer after drying was 2 g / m ² , The coated film was prepared by leaving to dry at 25 ° C. for 3 days. Thus, the transparency of the coating film was evaluated by measuring the haze of the whole coat film produced.

(4) Initial adhesiveness The adhesive film described in the examples was attached to a 1 mm thick polycarbonate plate (Mitsubishi Gas Co., Ltd., Iupilon NF2000) at a room temperature of 25 ° C. using a ² kg / cm ² pressure roller at a speed of 300 mm / min. It was. After leaving it at room temperature for 1 day, it is cut out to a width of 25 mm to make a measurement sample, and using a tensile tester (precision universal material testing machine type 2020 manufactured by Intesco), a coating speed of 200 mm / min and a tensile angle of 180 degrees is applied. The peel strength was evaluated.

(5) Adhesion with time The measurement sample of (4) was left in a gear oven at 50 ° C. for 1 day, and the peel strength was evaluated by the same method as in (4).

(6) Adherent contamination The surface of the polycarbonate plate after the end of the peel test of (4) and (5) is subjected to ATR measurement (Perkin Elmer System-2000 Fourier transform infrared spectrophotometer, resolution 4 cm ⁻¹ , 512 times integration). , Ge 60 ° prism was used) and the presence or absence of contaminants due to adhesive residue was confirmed.

(Polyolefin resin)
A commercially available polyolefin resin was used. The composition of the polyolefin resin used is shown in Table 1.

(Production of aqueous polyolefin resin dispersion “E-1”)
Using a stirrer equipped with a hermetic pressure-resistant 1 liter glass container with a heater, 60.0 g of polyolefin resin [Bondaine AX-8390, manufactured by Arkema Co., Ltd.], 100.0 g of n-propanol (manufactured by Wako Pure Chemical Industries, Ltd.) ), 2.5 g of triethylamine (manufactured by Wako Pure Chemical Industries, Ltd.) and 137.5 g of distilled water were charged into a glass container and stirred at a rotation speed of a stirring blade of 300 rpm. It was not recognized and it was confirmed that it was floating. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 120 ° C. and further stirred for 20 minutes. Then, after cooling to room temperature (about 25 ° C.) while stirring with air rotation at 300 rpm, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) As a result, a milky white uniform polyolefin resin aqueous dispersion “E-1” was obtained.

(Production of aqueous polyolefin resin dispersion “E-2”)
Using a stirrer equipped with a hermetic pressure-resistant 1 liter glass container with a heater, 60.0 g of polyolefin resin [Bondaine LX-4110, manufactured by Arkema Corporation], 75.0 g of n-propanol (manufactured by Wako Pure Chemical Industries, Ltd.) ), 2.5 g of triethylamine (manufactured by Wako Pure Chemical Industries, Ltd.) and 162.5 g of distilled water were charged into a glass container and stirred at a rotation speed of a stirring blade of 300 rpm. It was not recognized and it was confirmed that it was floating. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 120 ° C. and further stirred for 20 minutes. Then, after cooling to room temperature (about 25 ° C.) while stirring with air rotation at 300 rpm, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) As a result, a milky white uniform polyolefin resin aqueous dispersion “E-2” was obtained.

(Production of aqueous polyolefin resin dispersion “H-1”)
As the polyolefin resin, an ethylene-acrylic acid copolymer resin (Primacol 5980I, 20% by mass acrylic acid copolymer, manufactured by Dow Chemical) was used. Using a stirrer equipped with a hermetic pressure-resistant 1 liter glass container with a heater, 60.0 g of Primacol 5980I, 16.8 g of triethylamine, and 223.2 g of distilled water were charged into the glass container, and a stirring blade When stirring was performed at a rotation speed of 300 rpm, no precipitation of resin particles was observed at the bottom of the container, confirming that it was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 120 ° C. and further stirred for 40 minutes. Then, after cooling to room temperature (about 25 ° C.) while stirring with air rotation at 300 rpm, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) As a result, a slightly cloudy aqueous dispersion “H-1” was obtained.

  Properties of various aqueous dispersions are shown in Table 2.

Example 1
The aqueous dispersion “E-1” and the aqueous dispersion “E-2” were mixed and stirred at room temperature so that the solid content mass ratio of the polyolefin resin became 70/30, and this was further diluted with isopropanol and coated. This was applied to various thermoplastic resin films so that the adhesive layer coating amount after drying was 0.5 g / m ² and dried at 90 ° C. for 1 minute to obtain an adhesive film. Table 3 shows the results of various physical property evaluations.

(Example 2)
A pressure-sensitive adhesive film was prepared in the same manner as in Example 1 except that the aqueous dispersion “E-1” and the aqueous dispersion “E-2” were changed so that the solid content mass ratio of the polyolefin resin was 50/50. Obtained. Table 3 shows the results of various physical property evaluations.

(Example 3)
An adhesive film was obtained in the same manner as in Example 1 except that the aqueous dispersion “E-1” and the aqueous dispersion “E-2” were changed so that the solid content mass ratio of the polyolefin resin was 30/70. It was. Table 3 shows the results of various physical property evaluations.

Example 4
Polyvinyl alcohol (Unitika Chemical Co., UF170G, polymerization degree 1700, number average molecular weight 75000, saponification degree 99%) was used as the water-soluble polymer. Polyvinyl alcohol was dissolved in hot water to prepare a 3% by mass aqueous solution. Example 1 except that this was added so that the solid content of polyvinyl alcohol was 10 parts by mass with respect to 100 parts by mass of the polyolefin resin solids of the mixed liquid of E-1 and E-2 obtained in Example 3. In the same manner, an adhesive film was obtained. Table 3 shows the results of various physical property evaluations.

(Example 5)
An adhesive film was obtained in the same manner as in Example 1 except that the adhesive layer coating amount was changed to 0.2 g / m ² . Table 3 shows the results of various physical property evaluations.

(Example 6)
An adhesive film was obtained in the same manner as in Example 1 except that only the aqueous dispersion “E-1” was used and the amount of the adhesive layer applied was 0.2 g / m ² . Table 3 shows the results of various physical property evaluations.

(Comparative Example 1)
An adhesive film was obtained in the same manner as in Example 1 except that “H-1” was used instead of the aqueous dispersion “E-1”. Table 3 shows the results of various physical property evaluations.

(Comparative Examples 2 and 3)
A pressure-sensitive adhesive film was obtained in the same manner as in Example 1 except that “E-2” (Comparative Example 2) and “H-1” (Comparative Example 3) were used alone. Table 3 shows the results of various physical property evaluations.

  In Examples 1 to 6, in each adhesive film, the adhesive layer had good adhesion to various substrate films. Moreover, the adhesive film had moderate adhesiveness, and there was no big change in the adhesiveness with time (after long-term storage) under heating. Furthermore, there was no adhesive residue even after peeling (both initial and after time), and contamination of the adherend surface was not confirmed. In Example 4, the change in adhesiveness over time was suppressed by blending a water-soluble polymer.

On the other hand, in Comparative Examples 1 to 3, since the polyolefin resin composition of the adhesive layer was out of the scope of the present invention, the adhesion with the base film was inferior or the adhesiveness was not sufficient.

Claims (8)

A pressure-sensitive adhesive film comprising a pressure-sensitive adhesive layer containing a polyolefin resin (A) containing 0.01 to 7% by mass of an unsaturated carboxylic acid component and 28 to 45% by mass of a (meth) acrylic acid ester component. And the quantity of this adhesion layer is 0.01-5 g / m < ² >, The adhesion film characterized by the above-mentioned. The pressure-sensitive adhesive film according to claim 1, wherein the pressure-sensitive adhesive layer contains substantially no emulsifier component having a number average molecular weight of less than 10,000. The adhesive layer further contains a polyolefin resin (A ^* ) containing 0.01 to 7% by mass of an unsaturated carboxylic acid component and 0 to 12% by mass of a (meth) acrylic acid ester component. Item 3. The pressure-sensitive adhesive film according to item 1 or 2. The pressure-sensitive adhesive film according to claim 3, wherein the mass ratio (A) / (A ^* ) of the polyolefin resins (A) and (A ^* ) is 5/95 to 95/5. The pressure-sensitive adhesive layer further contains a water-soluble polymer compound having a number average molecular weight of 10,000 or more, and this content is 0.1 to 100 parts by mass with respect to a total of 100 parts by mass of the polyolefin resins (A) and (A ^* ). It is 30 mass parts, The adhesive film in any one of Claims 1-4 characterized by the above-mentioned. The pressure-sensitive adhesive film according to claim 1, wherein the resin film is a polyolefin resin film. It is a film used as a protective film, The adhesive film in any one of Claims 1-6. The method for producing an adhesive film according to any one of claims 1 to 7, wherein the aqueous medium is dried after an aqueous dispersion containing a polyolefin resin is applied to the surface of the resin film.