JP4841267B2 - Adhesive optical film - Google Patents

Description

  The present invention relates to an adhesive optical film. Specifically, the present invention relates to an adhesive optical film used as various optical films including an adhesive layer and an undercoat layer.

Conventionally, optical films such as a polarizing film, a retardation film, a brightness enhancement film, and a viewing angle widening film have been used for various industrial applications, for example, attached to a liquid crystal display or the like.
As an optical film to be attached to a liquid crystal display, an optical film in which an adhesive is laminated via an undercoat layer is known.

For example, an isocyanate-based polyfunctional compound is added to an acrylic polymer solution to prepare a pressure-sensitive adhesive solution, which is laminated (laminated) on a polarizing film with an undercoat layer (anchor layer) made of a water-dispersible polyester resin. An adhesive optical film has been proposed (see, for example, Patent Document 1).
For example, an adhesive optical film in which an adhesive layer is laminated on an optical film via an undercoat layer formed of a polyamine compound has been proposed (see, for example, Patent Document 2).

Further, for example, an adhesive polarizing plate is proposed in which an acrylic pressure-sensitive adhesive layer is laminated on a polarizing plate via an undercoat layer made of a polyacrylic ester having a primary amino group (for example, Patent Document 3). reference.).
JP 2004-54007 A JP 2004-78143 A Japanese Patent Laid-Open No. 10-20118

  However, conventional adhesives have low adhesion to optical films, and when attaching optical films to liquid crystal displays, it is usually necessary to adjust the position after attaching optical films to liquid crystal displays. In such a pressure-sensitive adhesive, the pressure-sensitive adhesive remains on the surface of the liquid crystal display at the time of peeling (hereinafter referred to as “pressure-sensitive adhesive residue”), and reworkability. There is a problem that is not enough.

In addition, when handling an adhesive optical film in handling processes such as cutting or transporting the adhesive optical film, if the end of the adhesive optical film comes into contact with a person or a nearby object, the adhesive of that part is lost (hereinafter referred to as “adhesive”). It is called “lack”.) When the adhesive optical film lacking the adhesive is stuck on the liquid crystal display in this way, there is a problem that display failure occurs.
Furthermore, the pressure-sensitive adhesive laminated as the pressure-sensitive adhesive optical film is required to have high heat resistance that does not cause defects even under severe heating. Further, depending on the application, it may be used not only under severe heating conditions but also under severe heating and humidification conditions, and high moisture and heat resistance is also required.

  An object of the present invention is to provide a pressure-sensitive adhesive optical film having high adhesive strength between the pressure-sensitive adhesive layer and the optical film, effectively suppressing the occurrence of pressure-sensitive adhesive residue and pressure-sensitive adhesive loss, and having high heat resistance and heat and moisture resistance. It is to provide.

In order to achieve the above object, the pressure-sensitive adhesive optical film of the present invention includes an optical film, a pressure-sensitive adhesive layer laminated on at least one surface of the optical film, and the optical film and the pressure-sensitive adhesive layer interposed therebetween. The pressure-sensitive adhesive layer is made of an acrylic pressure-sensitive adhesive, the undercoat layer contains only an oxazoline group-containing polymer as a polymer, and the oxazoline group-containing polymer has a main chain made of an acrylic skeleton. wherein, the main to the side chain of the chain Ri oxazoline group-containing acrylic polymer der containing an oxazoline group, the oxazoline group-containing polymers are water-soluble, oxazoline value is 220 g solid / eq. It is characterized by the following .

In the pressure-sensitive adhesive optical film of the present invention, it is preferable that the undercoat layer is made of a water-dispersed polymer .

In the pressure-sensitive adhesive optical film of the present invention, it is preferable that the acrylic pressure-sensitive adhesive is a water dispersion type.
In the pressure-sensitive adhesive optical film of the present invention, it is preferable that the pressure-sensitive adhesive layer contains a functional group that reacts with an oxazoline group .
Further, the pressure-sensitive adhesive optical film of the present invention, the functional group which reacts with oxazoline group, it is preferable that a carboxyl group.

  The pressure-sensitive adhesive optical film of the present invention has a high adhesive force between the pressure-sensitive adhesive layer and the optical film, and therefore can effectively reduce the occurrence of pressure-sensitive adhesive residue and pressure-sensitive adhesive loss when pasted on a liquid crystal display or the like. . Moreover, since it has high heat resistance and heat-and-moisture resistance, excellent durability can be obtained even in a high-temperature atmosphere or a high-temperature and high-humidity atmosphere.

The pressure-sensitive adhesive optical film of the present invention comprises an optical film, a pressure-sensitive adhesive layer laminated on at least one side of the optical film, and an undercoat that is interposed between the optical film and the pressure-sensitive adhesive layer and contains only the oxazoline group-containing polymer as a polymer. With layers.
In the present invention, the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer includes a pressure-sensitive adhesive usually used for the pressure-sensitive adhesive layer, and examples thereof include an acrylic pressure-sensitive adhesive and a natural rubber latex pressure-sensitive adhesive. An acrylic pressure-sensitive adhesive is preferable, and a water-dispersed acrylic pressure-sensitive adhesive is more preferable.

The acrylic pressure-sensitive adhesive contains (meth) acrylic acid alkyl ester as the monomer component.
Examples of the (meth) acrylic acid alkyl ester include compounds represented by the following general formula (1).

(In general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a linear or branched alkyl group having 1 to 18 carbon atoms.)
Examples of R ² include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, neopentyl group, isoamyl group, hexyl group, and heptyl group. Octyl group, 2-ethylhexyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, etc. Is mentioned.

  Specific examples of the (meth) acrylic acid alkyl ester include a methacrylic acid alkyl ester and / or an acrylic acid alkyl ester, such as methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylic. Propyl acid, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, ( Neopentyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acryl Isooctyl acid, nonyl (meth) acrylate, iso (meth) acrylate Nyl, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate And (meth) acrylic acid hexadecyl, (meth) acrylic acid heptadecyl, and (meth) acrylic acid octadecyl alkyl (meth) acrylates (linear or branched alkyl having 1 to 18 carbon atoms). These alkyl (meth) acrylates are used alone or in combination as appropriate. For example, butyl acrylate and 2-ethylhexyl acrylate may be used in combination, and the blending ratio (weight ratio) is, for example, 1/99 to 55/45 (butyl acrylate / 2-ethylhexyl acrylate). The ratio is preferably 5/95 to 60/40.

The blending ratio of the (meth) acrylic acid alkyl ester is, for example, 80 parts by weight or more, preferably 85 parts by weight or more, and more preferably 90 parts by weight or more with respect to 100 parts by weight of all monomer components.
The acrylic pressure-sensitive adhesive is a (meth) acrylic acid alkyl ester for the purpose of improving the adhesiveness of the pressure-sensitive adhesive layer to the adherend by introducing a crosslinking point (functional group) for thermal crosslinking. In addition, the monomer component preferably contains a functional group-containing monomer.

  Examples of functional group-containing monomers include carboxyl group-containing unsaturated monomers such as (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid, such as itaconic anhydride, maleic anhydride, and fumaric anhydride. Hydroxyl group-containing unsaturated monomers such as acid anhydride group-containing unsaturated monomers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, such as (meth) acrylamide, N, N- Dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-methylol (meth) acrylamide, N -Amide groups such as methylolpropane (meth) acrylamide Containing unsaturated monomers, for example, amino group-containing unsaturated monomers such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate, such as ( Glycidyl group-containing unsaturated monomers such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate, for example, cyano group-containing unsaturated monomers such as (meth) acrylonitrile, such as N-cyclohexylmaleimide, N-isopropylmaleimide, N -Maleimide group-containing monomers such as laurylmaleimide and N-phenylmaleimide, such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N -Cyclohexyl tacon Itaconimide group-containing monomers such as imide and N-laurylitaconimide, such as N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, N- (meth) acryloyl-8-oxy Succinimide group-containing monomers such as octamethylene succinimide, such as N-vinylpyrrolidone, N- (1-methylvinyl) pyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine , N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, vinyl group-containing heterocyclic compounds such as (meth) acryloylmorpholine, such as styrene sulfonic acid, allyl sulfonic acid, 2- (meth) A Sulfonic acid group-containing unsaturated monomers such as rilamido-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid, such as 2-hydroxyethylacryloylphos Examples include phosphate group-containing unsaturated monomers such as fate, functional monomers such as 2-methacryloyloxyethyl isocyanate, and other N-vinylcarboxylic acid amides.

Furthermore, a polyfunctional monomer is mentioned as a functional group containing monomer.
Examples of the multifunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and tetraethylene glycol di (meth) acrylate. (Mono or poly) alkylene glycol di (meth) such as (mono or poly) ethylene glycol di (meth) acrylate and (mono or poly) propylene glycol di (meth) acrylate such as propylene glycol di (meth) acrylate In addition to acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol Examples include tall tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and divinylbenzene. Examples of the polyfunctional monomer include epoxy acrylate, polyester acrylate, and urethane acrylate.

The functional group-containing monomer is appropriately used alone or in combination.
Of these functional group-containing monomers, a carboxyl group-containing unsaturated monomer and an acid anhydride group-containing unsaturated monomer are preferable. If it is a carboxyl group-containing unsaturated monomer or an acid anhydride group-containing unsaturated monomer, the carboxyl group contained in or generated from these is the oxazoline group of the oxazoline group-containing polymer that forms the undercoat layer described later, or a polyamine type It can react efficiently with the amino group of the polymer to enhance the adhesion with the optical film.

The compounding ratio of the functional group-containing monomer is, for example, 0.5 to 12 parts by weight, preferably 1 to 8 parts by weight with respect to 100 parts by weight of the (meth) acrylic acid alkyl ester.
The acrylic pressure-sensitive adhesive may contain a copolymerizable monomer copolymerizable with the above-mentioned (meth) acrylic acid acrylic ester as a monomer component for the purpose of improving various properties such as cohesive force. .

  Examples of the copolymerizable monomer include vinyl ester group-containing monomers such as vinyl acetate, aromatic unsaturated monomers such as styrene and vinyltoluene, such as cyclopentyl di (meth) acrylate and isobornyl (meth) acrylate ( (Meth) acrylic acid alicyclic hydrocarbon ester monomers such as neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol (Meth) acrylic acid ester monomers of polyhydric alcohols such as methanetri (meth) acrylate and dipentaerythritol hexa (meth) acrylate, such as methoxyethyl (meth) acrylate, (meth) acrylic acid Alkoxy group-containing unsaturated monomers such as toxiethyl, for example, olefinic monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene, vinyl ether-based monomers such as vinyl ether, halogen-containing unsaturated monomers such as vinyl chloride, etc. Examples thereof include tetrahydrofurfuryl (meth) acrylate and heterocycles such as fluorine (meth) acrylate, and acrylate monomers containing halogen atoms.

Furthermore, examples of the copolymerizable monomer include alkoxysilyl group-containing vinyl monomers. Examples of the alkoxysilyl group-containing vinyl monomer include silicone-based (meth) acrylate monomers and silicone-based vinyl monomers.
Examples of the silicone-based (meth) acrylate monomer include (meth) acryloyloxymethyl-trimethoxysilane, (meth) acryloyloxymethyl-triethoxysilane, 2- (meth) acryloyloxyethyl-trimethoxysilane, 2- ( (Meth) acryloyloxyethyl-triethoxysilane, 3- (meth) acryloyloxypropyl-trimethoxysilane, 3- (meth) acryloyloxypropyl-triethoxysilane, 3- (meth) acryloyloxypropyl-tripropoxysilane, 3 -(Meth) acryloyloxypropyl-triisopropoxysilane, (meth) acryloyloxyalkyl-trialkoxysilane such as 3- (meth) acryloyloxypropyl-tributoxysilane, for example, (meth) acryloyloxymethyl-methyl Dimethoxysilane, (meth) acryloyloxymethyl-methyldiethoxysilane, 2- (meth) acryloyloxyethyl-methyldimethoxysilane, 2- (meth) acryloyloxyethyl-methyldiethoxysilane, 3- (meth) acryloyloxypropyl -Methyldimethoxysilane, 3- (meth) acryloyloxypropyl-methyldiethoxysilane, 3- (meth) acryloyloxypropyl-methyldipropoxysilane, 3- (meth) acryloyloxypropyl-methyldiisopropoxysilane, 3- (Meth) acryloyloxypropyl-methyldibutoxysilane, 3- (meth) acryloyloxypropyl-ethyldimethoxysilane, 3- (meth) acryloyloxypropyl-ethyldiethoxysilane, 3- (meth) acryloyloxypropyl Ethyl dipropoxysilane, 3- (meth) acryloyloxypropyl-ethyldiisopropoxysilane, 3- (meth) acryloyloxypropyl-ethyldibutoxysilane, 3- (meth) acryloyloxypropyl-propyldimethoxysilane, 3- ( Examples include (meth) acryloyloxyalkyl-alkyl dialkoxysilanes such as (meth) acryloyloxypropyl-propyldiethoxysilane, and (meth) acryloyloxyalkyl-dialkyl (mono) alkoxysilanes corresponding to these.

  Examples of the silicone-based vinyl monomer include vinyltrialkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, and vinyl corresponding to these. Alkyldialkoxysilanes and vinyldialkylalkoxysilanes such as vinylmethyltrimethoxysilane, vinylmethyltriethoxysilane, β-vinylethyltrimethoxysilane, β-vinylethyltriethoxysilane, γ-vinylpropyltrimethoxysilane, γ -Vinylalkyl such as vinylpropyltriethoxysilane, γ-vinylpropyltripropoxysilane, γ-vinylpropyltriisopropoxysilane, γ-vinylpropyltributoxysilane Another trialkoxysilane, these correspond and (vinyl) alkyl dialkoxy silanes, and the like (vinyl alkyl) dialkyl (mono) alkoxysilanes.

  By using an alkoxysilyl group-containing vinyl monomer as a copolymerizable vinyl monomer, an alkoxysilyl group is introduced into the polymer chain, and a cross-linked structure can be formed by a reaction between them. In particular, in the acrylic adhesive, since the crosslinking agent described later has a non-uniform crosslinked structure, the end of the adhesive optical film is easily peeled off when used in a high temperature atmosphere or the like. However, when an alkoxysilyl group-containing monomer is used, a uniform cross-linked structure can be formed, so that adhesion and fixation to a glass substrate such as a liquid crystal display can be improved. In addition, the alkoxysilyl group can interact with the glass substrate to enhance the adhesion to the glass substrate.

These copolymerizable monomers are suitably used alone or in combination.
The blending ratio of the copolymerizable monomer is, for example, 30 parts by weight or less, preferably 15 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic acid alkyl ester.
The acrylic pressure-sensitive adhesive is not particularly limited, and the above-described monomer component is polymerized by a known polymerization method such as solution polymerization with an organic solvent or emulsion polymerization in water.

  For example, in emulsion polymerization, a polymerization initiator, an emulsifier, and, if necessary, a chain transfer agent are appropriately blended in water together with the above monomer components for polymerization. More specifically, for example, known emulsion polymerization methods such as a batch charging method (batch polymerization method), a monomer dropping method, and a monomer emulsion dropping method can be employed. In the monomer dropping method, continuous dropping or divided dropping is appropriately selected. Although reaction conditions etc. are selected suitably, superposition | polymerization temperature is 20-90 degreeC, for example.

  The polymerization initiator is not particularly limited, and a polymerization initiator usually used for emulsion polymerization is used. For example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (2-methylpropionamidine) dihydrochloride, 2, 2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate, 2,2′-azobis (N, N Azo initiators such as' -dimethyleneisobutylamidine), 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, for example, persulfate such as potassium persulfate and ammonium persulfate Salt-based initiators, for example, peroxide-based initiators such as benzoyl peroxide, t-butyl hydroperoxide, and hydrogen peroxide, for example, substituted ethers such as phenyl-substituted ethane. For example, carbonyl initiators such as aromatic carbonyl compounds, redox initiators such as a combination of persulfate and sodium bisulfite, a combination of peroxide and sodium ascorbate, etc. It is done.

These polymerization initiators are suitably used alone or in combination. Moreover, although the mixture ratio of a polymerization initiator is suitably selected, it is 0.005-1 weight part with respect to 100 weight part of all the monomer components, for example.
The emulsifier is not particularly limited, and an emulsifier usually used for emulsion polymerization is used. For example, sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium polyoxyethylene lauryl sulfate, sodium polyoxyethylene alkyl ether sulfate, ammonium polyoxyethylene alkyl phenyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene Anionic emulsifiers such as sodium alkylsulfosuccinate, for example, nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene polyoxypropylene block polymer.

In addition, radically polymerizable (reactive) emulsifiers (for example, HS-10 (No. 1), in which radically polymerizable functional groups (reactive groups) such as propenyl groups and allyl ether groups are introduced into these anionic and nonionic emulsifiers. Ichi Kogyo Seiyaku Co., Ltd.)).
These emulsifiers are used alone or in combination as appropriate. Moreover, the mixture ratio of an emulsifier is 0.2-10 weight part with respect to 100 weight part of all the monomer components, Preferably, it is 0.5-5 weight part.

The chain transfer agent adjusts the molecular weight of the acrylic pressure-sensitive adhesive if necessary, and a chain transfer agent usually used for emulsion polymerization is used. Examples thereof include mercaptans such as 1-dodecanethiol, mercaptoacetic acid, 2-mercaptoethanol, 2-ethylhexyl thioglycolate, and 2,3-dimethylcapto-1-propanol.
These chain transfer agents are appropriately used alone or in combination. Moreover, the mixture ratio of a chain transfer agent is 0.001-0.5 weight part with respect to 100 weight part of all the monomer components, for example.

Then, by such emulsion polymerization, the acrylic pressure-sensitive adhesive can be prepared as a water-dispersed acrylic pressure-sensitive adhesive, that is, an aqueous dispersion emulsion (water dispersion).
The water-dispersed acrylic pressure-sensitive adhesive can also be prepared, for example, by polymerizing the above-described monomer component by a method other than emulsion polymerization and then dispersing it in water using the above-described emulsifier.

  Moreover, you may mix | blend a crosslinking agent with an adhesive according to the objective and use as needed. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, and a metal chelate crosslinking agent. These crosslinking agents are not particularly limited, and oil-soluble or water-soluble crosslinking agents are used. These crosslinking agents are suitably used alone or in combination, and the blending ratio thereof is, for example, 0.1 to 10 parts by weight with respect to 100 parts by weight of the total monomer components.

Further, when the pressure-sensitive adhesive is a water-dispersed pressure-sensitive adhesive, the pH is adjusted to, for example, pH 7 to 9, preferably pH 7 to 8, for example, with ammonia water for the purpose of improving the stability of the emulsion. .
In addition, adhesives include viscosity modifiers, and if necessary, adhesives such as release modifiers, plasticizers, softeners, fillers, colorants (pigments, dyes, etc.), anti-aging agents, surfactants, etc. Additives that are usually added may be added as appropriate. The mixing ratio of these additives is not particularly limited, and can be appropriately selected.

The viscosity modifier is not particularly limited, and examples thereof include an acrylic thickener.
Such a pressure-sensitive adhesive has a gel fraction of, for example, 50 to 100% by weight, preferably 70 to 100% by weight. If the gel fraction is lower than the above value, foaming or peeling may occur when this adhesive is applied to an adhesive optical film and used in a high temperature and high humidity atmosphere.

The gel fraction can be calculated by the following formula when the pressure-sensitive adhesive is covered with, for example, a Teflon (registered trademark) sheet and immersed in ethyl acetate for 7 days.
Gel fraction (% by weight) = (weight of adhesive attached to Teflon sheet after immersion / weight of adhesive before immersion) × 100
The oxazoline group-containing polymer includes, for example, a main chain composed of an acrylic skeleton or a styrene skeleton, and has an oxazoline group in the side chain of the main chain, and preferably includes a main chain composed of an acrylic skeleton. And an oxazoline group-containing acrylic polymer having an oxazoline group in the side chain of the main chain.

Examples of the oxazoline group include 2-oxazoline group, 3-oxazoline group, 4-oxazoline group, and preferably 2-oxazoline group.
The 2-oxazoline group is generally represented by the following general formula (2).

(In general formula (2), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, a phenyl group or a substituted phenyl group.)
The number average molecular weight of the oxazoline group-containing polymer is, for example, 5000 or more, preferably 10,000 or more, and usually 1000000 or less. When the number average molecular weight is lower than 5000, the strength of the undercoat layer is insufficient, causing cohesive failure, and the anchoring force may not be improved. When the number average molecular weight is higher than 1,000,000, workability may be inferior. The oxazoline group-containing polymer has an oxazoline value of, for example, 1500 g solid / eq. Hereinafter, preferably, 1200 g solid / eq. It is as follows. The oxazoline value is 1500 g solid / eq. If it is larger, the amount of the oxazoline group contained in the molecule decreases, and the anchoring force may not be improved.

The oxazoline group-containing polymer has a pressure-sensitive adhesive layer if the oxazoline group-containing polymer is contained in the undercoat layer because the oxazoline group reacts with a functional group (such as a carboxyl group or a hydroxyl group) contained in the pressure-sensitive adhesive at a relatively low temperature. It reacts with the functional groups in it and can adhere firmly.
As the oxazoline group-containing polymer, a general commercial product is usually used. Specifically, Epocros WS-500 (aqueous solution type, solid content 40%, main chain: acrylic, pH 7-9, oxazoline value 220 g solid / eq , Manufactured by Nippon Shokubai Co., Ltd.), Epocross WS-700 (aqueous solution type, solid content 25%, main chain: acrylic, pH 7-9, oxazoline value 220 g solid / eq., Manufactured by Nippon Shokubai Co., Ltd.) Oxazoline group-containing acrylic polymer, for example, Epocross K-1000 series (emulsion type, solid content 40%, main chain: styrene / acrylic, oxazoline value 1100 g solid / eq., PH 7-9, manufactured by Nippon Shokubai Co., Ltd.) Epocross K-2000 series (emulsion type, solid content 40%, main chain: styrene / a Lil system, pH 7-9, oxazoline value 550 g solid / eq., And the like oxazoline group-containing acrylic / styrene polymers, such as KK Nippon Shokubai). From the viewpoint of improving adhesion, an aqueous solution type oxazoline group-containing acrylic polymer is preferable to an emulsion type containing an emulsifier.

With such an oxazoline group-containing acrylic polymer, it is possible to obtain a pressure-sensitive adhesive optical film having high heat resistance by improving the adhesion between the optical film and the pressure-sensitive adhesive with good affinity with the pressure-sensitive adhesive. it can.
Such an oxazoline group-containing polymer is generally dissolved or dispersed in a solution such as an organic solvent or water, and is prepared as a resin solution or an aqueous dispersion containing the oxazoline group-containing polymer. In addition, it is preferable to prepare as an aqueous dispersion from a viewpoint of preventing deterioration of the optical film.

In the pressure-sensitive adhesive optical film of the present invention, the undercoat layer is preferably composed of a mixture of an oxazoline group-containing polymer and a polyamine polymer.
The polyamine-based polymer is a polymer having a plurality of primary or secondary amino groups in the molecule, and includes, for example, polyethyleneimine, polyallylamine, and a main chain composed of an acrylic skeleton, and a side chain of the main chain. Examples thereof include an ethyleneimine-modified acrylic polymer and an allylamine-modified acrylic polymer in which a polyethyleneimine chain represented by the following general formula (3) and a polyallylamine chain represented by the following general formula (4) are modified. . Preferably, an ethyleneimine modified acrylic polymer is used.

(In general formula (3), x and y indicate the degree of polymerization of the polyethyleneimine chain.)

(In general formula (4), z represents the degree of polymerization of the polyallylamine chain.)
The number average molecular weight of the polyamine polymer is, for example, 200 or more, preferably 1000 or more, more preferably 8000 or more, and usually 1000000 or less. If the number average molecular weight is less than 200, the strength of the undercoat layer is insufficient, causing cohesive failure, and the anchoring force may not be improved. When the number average molecular weight is larger than 1,000,000, workability may be inferior. The polyamine polymer has an amine hydrogen equivalent of, for example, 1500 g solid / eq. Hereinafter, preferably, 1200 g solid / eq. It is as follows. The amine hydrogen equivalent weight is 1500 g solid / eq. If it is larger, the amount of amino groups contained in the molecule decreases, and the anchoring power may not be improved.

  As the polyamine polymer, a general commercial product is usually used. Specifically, Epomin SP-003 (water-soluble type, amine hydrogen equivalent 47.6 g solid / eq., Manufactured by Nippon Shokubai Co., Ltd.), Epomin SP -006 (water-soluble type, amine hydrogen equivalent 50.0 g solid / eq., Manufactured by Nippon Shokubai Co., Ltd.), Epomin SP-012 (water-soluble type, amine hydrogen equivalent 52.6 g solid / eq., Japan) Catalyst), Epomin SP-018 (water-soluble type, amine hydrogen equivalent 52.6 g solid / eq., Nippon Shokubai Co., Ltd.), Epomin SP-103 (water-soluble type, amine hydrogen equivalent 52.6 g solid / eq) Epomin SP-110 (water-soluble type, amine hydrogen equivalent 55.6 g solid / eq., Nippon Touch Co., Ltd.) Epomin SP-200 (water-soluble type, amine hydrogen equivalent 55.6 g solid / eq., Manufactured by Nippon Shokubai Co., Ltd.), Epomin P-1000 (water-soluble type, amine hydrogen equivalent 52.6 g solid / eq. , Polyimine SK-1000 (emulsion type, amine hydrogen equivalent 650 g solid / eq., Manufactured by Nippon Shokubai Co., Ltd.), polyment NK-350 (solvent type, amine hydrogen) Equivalent 1100 g solid / eq., Manufactured by Nippon Shokubai Co., Ltd., Poliment NK-380 (solvent type, amine hydrogen equivalent 1100 g solid / eq., Manufactured by Nippon Shokubai Co., Ltd.), Poliment NK-100PM (water-soluble type, amine) Hydrogen equivalent 350-450 g solid / eq. (Made by Nippon Shokubai Co., Ltd.) POLYMENT NK-200 pM (soluble type, amine hydrogen equivalent 350~450g solid / eq., (Ltd.) manufactured by Nippon Shokubai Co., Ltd.) and the like ethyleneimine-modified acrylic polymer, such as.

The mixing ratio of the polyamine polymer is, for example, 70 to 98 parts by weight, preferably 70 to 97 parts by weight, more preferably 80 to 95 parts per 100 parts by weight of the total amount of the oxazoline group-containing polymer and the polyamine polymer. Parts by weight. If the polyamine polymer is less than 70 parts by weight, the heat and moisture resistance may be poor. When the amount of the polyamine polymer is more than 98 parts by weight, the heat resistance may be inferior.

  Such a mixture of an oxazoline group-containing polymer and a polyamine polymer is generally dissolved or dispersed in a solution such as an organic solvent or water, and a resin solution or a mixture of an oxazoline group-containing polymer and a polyamine polymer is used. It is prepared as an aqueous dispersion. Preferably, the mixture is prepared as a water-dispersed mixture of an oxazoline group-containing polymer and a polyamine polymer (water-dispersed polymer) in which the mixture is dispersed in water.

Thus, if the undercoat layer is composed of a mixture of an oxazoline group-containing polymer and a polyamine polymer, the adhesive optical film is maintained while maintaining the high adhesion and heat resistance when only the oxazoline group-containing polymer is comprised. High pressure-and-moisture resistance can be imparted, and an adhesive optical film having high adhesion, heat resistance, and heat-and-moisture resistance can be obtained.
In addition to the effect of increasing the adhesion due to the hydrogen bond and acid-base interaction due to the amino group of the polyamine polymer, such an effect, the undercoat layer is cross-linked by the reaction between the oxazoline group-containing polymer and the polyamine polymer, resulting in a strong By becoming an undercoat layer, it is estimated that heat resistance and heat-and-moisture resistance become high.

In the pressure-sensitive adhesive optical film of the present invention, the undercoat layer is also preferably composed of a mixture of an oxazoline group-containing polymer and a compound containing a plurality of carboxyl groups .

The compounds containing multiple carboxyl group, a polymer compound (polymer of unsaturated compound containing a carboxyl group), for example, a polymer of unsaturated compounds such as acrylic acid, methacrylic acid (polyacrylic Acid, polymethacrylic acid, etc.), for example, copolymers of these unsaturated compounds, specifically copolymers of acrylic acid and methacrylic acid, copolymers of acrylic acid and maleic acid, methacrylic acid and maleic acid Examples thereof include a copolymer, a copolymer of acrylic acid, methacrylic acid and maleic acid. Preferably, a copolymer of acrylic acid and maleic acid is used.

The compound containing a plurality of carboxyl groups has a number average molecular weight (GPC measurement, standard polyethylene glycol equivalent) of, for example, 1000 or more, preferably 3000 to 200000.
Moreover, the carboxyl group which the compound containing a some carboxyl group has may form the salt with the cation all or one part.

Examples of the cation include inorganic cations such as potassium ion and sodium ion, for example, ammonium cations, and organic cations such as primary amine, secondary amine, and tertiary amine cations.
As the compound containing a plurality of carboxyl groups, generally commercially available products are used. Specifically, Poise 532A (acrylic acid / maleic acid copolymer ammonium salt, number average molecular weight of about 10,000, manufactured by Kao Corporation) ) And the like.

  A mixture of such an oxazoline group-containing polymer and a compound containing a plurality of carboxyl groups is generally dissolved or dispersed in a solution such as an organic solvent or water, and the oxazoline group-containing polymer and a plurality of carboxyl groups are combined. It is prepared as a resin solution or aqueous dispersion of a mixture with the contained compound. Preferably, the mixture is prepared as a water-dispersed mixture of an oxazoline group-containing polymer and a compound containing a plurality of carboxyl groups (water-dispersed polymer).

  In general, when a water-soluble material is used as the undercoat layer, if the thickness of the undercoat layer increases, the strength of the undercoat layer may decrease when used in a high-humidity atmosphere, resulting in interlaminar fracture. . However, if the undercoat layer is a mixture of an oxazoline group-containing polymer and a compound containing a plurality of carboxyl groups, the oxazoline group of the oxazoline group-containing polymer and the carboxyl group of the compound containing a plurality of carboxyl groups As a result of the reaction, the undercoat layer is cross-linked to become a stronger undercoat layer, and thus it is presumed that the heat resistance and heat-and-moisture resistance are increased and the adhesion is increased.

  The compounding ratio of the compound containing a plurality of carboxyl groups is, for example, 1 to 30 parts by weight, preferably 2 to 20 parts per 100 parts by weight of the total amount of the oxazoline group-containing polymer and the compound containing a plurality of carboxyl groups. Part by weight, more preferably 3 to 10 parts by weight. If the compound containing a plurality of carboxyl groups is less than 1 part by weight, the effect of crosslinking the undercoat layer may be reduced. When the compound containing a plurality of carboxyl groups is more than 30 parts by weight, the undercoat layer may become cloudy and optical properties may be deteriorated.

Furthermore, in the pressure-sensitive adhesive optical film of the present invention, the undercoat layer is preferably composed of a mixture of an oxazoline group-containing polymer, a polyamine-based polymer, and a compound containing a plurality of carboxyl groups.
The blending ratio of the polyamine polymer is, for example, 50 to 98 parts by weight, preferably 70 to 97 parts by weight with respect to 100 parts by weight of the total amount of the oxazoline group-containing polymer, the polyamine polymer, and the compound containing a plurality of carboxyl groups. Parts, more preferably 80 to 95 parts by weight. If the polyamine polymer is less than 50 parts by weight, the heat and moisture resistance may be poor. When the amount of the polyamine polymer is more than 98 parts by weight, the heat resistance may be inferior.

  The compounding ratio of the compound containing a plurality of carboxyl groups is, for example, 1 to 30 parts by weight, preferably 100 parts by weight based on the total amount of the oxazoline group-containing polymer, the polyamine polymer and the compound containing a plurality of carboxyl groups, 2 to 20 parts by weight, more preferably 3 to 10 parts by weight. If the compound containing a plurality of carboxyl groups is less than 1 part by weight, the effect of crosslinking the undercoat layer may be reduced. When the compound containing a plurality of carboxyl groups is more than 30 parts by weight, the undercoat layer may become cloudy and optical properties may be deteriorated.

  Such a mixture of an oxazoline group-containing polymer, a polyamine polymer, and a compound containing a plurality of carboxyl groups is generally dissolved or dispersed in a solution such as an organic solvent or water, and the oxazoline group-containing polymer and the polyamine are mixed. It is prepared as a resin solution or an aqueous dispersion of a mixture of a system polymer and a compound containing a plurality of carboxyl groups. Preferably, these mixtures are prepared as a water-dispersed mixture of an oxazoline group-containing polymer, a polyamine polymer, and a compound containing a plurality of carboxyl groups (water-dispersed polymer). .

Hereinafter, with reference to FIG. 1, the manufacturing method of the adhesive optical film of this invention is demonstrated.
In order to obtain the adhesive optical film shown in FIG. 1, first, an optical film 1 is prepared.
The optical film 1 is not particularly limited as long as it has optical characteristics and is attached to a liquid crystal display, and examples thereof include a polarizing film, a retardation film, a brightness enhancement film, and a viewing angle widening film. .

As a polarizing film, what provided the transparent protective film on the single side | surface or both surfaces of a polarizer is used.
The polarizer is not particularly limited, and examples thereof include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, ethylene / vinyl acetate copolymer partially saponified films, iodine and dichroism. Examples thereof include uniaxially stretched films dyed with dichroic substances such as dyes, and polyene-based oriented films such as polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Preferably, a polarizer obtained by uniaxially stretching a polyvinyl alcohol film with iodine is used.

  Examples of the transparent protective film include polyester polymer films such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymer films such as diacetyl cellulose and triacetyl cellulose, acrylic polymer films such as polymethyl methacrylate, polystyrene, acrylonitrile and styrene. Examples thereof include a styrene polymer film such as a polymer (AS resin), and a polycarbonate polymer film. In addition, polyethylene, polypropylene, polyolefin having a cyclo or norbornene structure, polyolefin polymer film such as ethylene / propylene copolymer, vinyl chloride polymer film, nylon, amide polymer film such as aromatic polyamide, imide polymer film, Sulfone polymer film, polyether sulfone polymer film, polyether ether ketone polymer film, polyphenylene sulfide polymer film, vinyl alcohol polymer film, vinylidene chloride polymer film, vinyl butyral polymer film, arylate polymer film, poly Of oxymethylene-based polymer film, epoxy-based polymer film, or blends of the above-mentioned polymers Irumu also include such.

The transparent protective film can also be formed as a cured layer of thermosetting or ultraviolet curable resin such as acrylic, urethane, acrylurethane, epoxy, and silicone.
As a transparent protective film, Preferably, a cellulose polymer is mentioned. The thickness in particular of a transparent protective film is not restrict | limited, For example, it is 500 micrometers or less, Preferably, it is 1-300 micrometers, More preferably, it is 5-200 micrometers.

In order to bond the polarizer and the transparent protective film, for example, an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based adhesive, a latex-based adhesive, a water-based polyester adhesive, or the like is used. Glue.
Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a liquid crystal polymer alignment layer supported by the film. The thickness of the retardation film is not particularly limited and is, for example, 20 to 150 μm.

  Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, Polyphenylene sulfide, polyphenylene oxide, polyallylsulfone, polyvinyl alcohol, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose polymer, or binary, ternary copolymers, graft copolymers, blends Such as things. These polymer materials become an oriented product (stretched film) by stretching or the like.

  Examples of the liquid crystalline polymer include various main chain types and side chain types in which a conjugated linear atomic group (mesogen) imparting liquid crystal orientation is introduced into the main chain or side chain of the polymer. It is done. As the main chain type liquid crystalline polymer, for example, a structure in which a mesogenic group is bonded at a spacer portion imparting flexibility, specifically, a nematic orientation polyester-based liquid crystalline polymer, a discotic polymer or a cholesteric polymer. Etc. As the side chain type liquid crystalline polymer, for example, polysiloxane, polyacrylate, polymethacrylate or polymalonate is used as the main chain skeleton, and the side chain is substituted by a nematic orientation-imparting para-substitution through a spacer portion composed of a conjugated atomic group. Examples thereof include those having a mesogenic part composed of a cyclic compound unit. These liquid crystalline polymers are prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment-treated surface such as a surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or an oblique deposition of silicon oxide. It is obtained by developing and heat treatment.

In addition, the retardation film may be, for example, a film for the purpose of expanding coloring or viewing angle due to birefringence of various wavelength films or liquid crystal layers, or may have a phase difference as appropriate depending on the purpose of use. Two or more retardation films may be laminated to control optical characteristics such as retardation.
Examples of brightness enhancement films are those that transmit linearly polarized light with a predetermined polarization axis and reflect other light, such as dielectric multilayer thin films and multilayer laminates of thin film films with different refractive index anisotropies. , Cholesteric liquid crystal polymer alignment films and those whose alignment liquid crystal layer is supported on a film substrate, such as those that reflect either left-handed or right-handed circularly polarized light and transmit other light, etc. Is mentioned.

  The viewing angle widening film is a film that widens the viewing angle so that the image can be seen relatively clearly even when the screen of the liquid crystal display is viewed from a slightly oblique direction rather than perpendicular to the screen. Examples thereof include an alignment film such as a film and a liquid crystal polymer, and a support in which an alignment layer such as a liquid crystal polymer is supported on a transparent substrate. Retardation films used as viewing angle widening films include birefringent polymer films stretched biaxially in the plane direction and thickness direction refractions stretched uniaxially in the plane direction and stretched in the thickness direction. A birefringent film such as a polymer having birefringence with a controlled rate or a tilted orientation film is used.

Then, the undercoat layer 2 is provided on one side of the optical film 1. In this description, the undercoat layer 2 is provided on one side of the optical film, but may be provided on both sides if necessary.
In order to provide the undercoat layer 2, for example, the optical film 1 is provided with an oxazoline group-containing polymer, a mixture of an oxazoline group-containing polymer and a polyamine polymer, a mixture of an oxazoline group-containing polymer and a compound containing a plurality of carboxyl groups, or A resin solution or an aqueous dispersion of a mixture of an oxazoline group-containing polymer, a polyamine polymer, and a compound containing a plurality of carboxyl groups is directly coated and dried by a known coating method such as a knife coating method.

The thickness (thickness after drying) of the undercoat layer 2 is set to, for example, 1 to 500 nm, preferably 10 to 450 nm, and more preferably 20 to 400 nm. If the thickness of the undercoat layer is set within the above-described range, the adhesion between the optical film 1 and the pressure-sensitive adhesive layer 3 can be sufficiently increased.
Next, the pressure-sensitive adhesive layer 3 is provided on at least one surface of the optical film 1 via the undercoat layer 2.

  In order to provide the pressure-sensitive adhesive layer 3, for example, a method of transferring the pressure-sensitive adhesive layer 3 from the release sheet 4 on which the pressure-sensitive adhesive layer 3 is formed to the above-described undercoat layer 2 can be mentioned. The release sheet 4 on which the pressure-sensitive adhesive layer 3 has been formed can be prepared by directly coating the release sheet 4 with a pressure-sensitive adhesive by a known coating method such as a knife coating method and drying it. Further, in order to transfer the pressure-sensitive adhesive layer 3, the release sheet 4 on which the pressure-sensitive adhesive layer 3 is formed is brought into contact with the optical film 1 on which the undercoat layer 2 is provided. Thus, after bonding together, the release sheet 4 is peeled off from the adhesive layer 3.

In order to provide the pressure-sensitive adhesive layer 3, for example, the pressure-sensitive adhesive can be directly coated on the undercoat layer 2 by a known coating method such as a knife coating method and dried.
Examples of the release sheet 4 include paper, synthetic resin films such as polyethylene, polypropylene, and polyethylene terephthalate, rubber sheets, paper, cloth, nonwoven fabric, nets, foamed sheets, metal foils, and laminated sheet bodies thereof. In order to improve the peelability from the pressure-sensitive adhesive layer 3, the surface of the release sheet 4 may be subjected to treatments such as silicone treatment, long-chain alkyl treatment, and fluorine treatment as necessary.

The thickness (thickness after drying) of the pressure-sensitive adhesive layer 3 is set, for example, in the range of 1 to 100 μm, preferably 5 to 50 μm, and more preferably 10 to 40 μm.
Thus, by providing the pressure-sensitive adhesive layer 3 made of a pressure-sensitive adhesive on at least one surface of the optical film 1 via the undercoat layer 2, the pressure-sensitive adhesive optical film of the present invention can be obtained.
The adhesive optical film of the present invention thus obtained can be used in various industries as an optical film such as a polarizing film, a retardation film, a brightness enhancement film, and a viewing angle widening film without impairing the optical properties of the optical film. It is suitably used for applications.

  In particular, since such an adhesive optical film has a high adhesive force between the adhesive layer 3 and the optical film 1, when adhering to a liquid crystal display or the like, after adhering the optical film to the liquid crystal display, position For adjustment, even if it is once peeled off and reattached (reworked), the remaining adhesive can be effectively suppressed and reworked at the time of peeling. Therefore, efficient sticking work can be realized.

Also, when handling in the usage process such as cutting and transporting the adhesive optical film, even if the end of the adhesive optical film comes into contact with people or other objects, it is possible to effectively suppress adhesive chipping. In addition, it is possible to effectively prevent display defects of the liquid crystal display due to the lack of adhesive.
Furthermore, since such an adhesive optical film has high heat resistance, if it is attached to a liquid crystal display or the like, it can effectively prevent a decrease in adhesion with the liquid crystal display even in a high temperature atmosphere. Excellent durability can be obtained even in an atmosphere.

  Furthermore, since such an adhesive optical film has high moisture and heat resistance, if it is attached to a liquid crystal display or the like, it effectively prevents a decrease in adhesion to the liquid crystal display even in a high temperature and high humidity atmosphere. Excellent durability can be obtained even in a high temperature and high humidity atmosphere.

Hereinafter, the present invention will be described more specifically with reference to Examples , Reference Examples and Comparative Examples. However, the present invention is not limited to the following examples , reference examples and comparative examples. In the following description, “parts” and “%” are based on weight unless otherwise specified.
(Preparation of water-dispersed acrylic adhesive)
In a container, 95.2 parts of butyl acrylate, 4.76 parts of acrylic acid, 0.02 part of 3-methacryloxypropyl-trimethoxysilane (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.), reactive emulsifier Aqualon HS -10 (Daiichi Kogyo Seiyaku Co., Ltd.) 2.0 parts (solid content) and 57.4 parts of water were added, and the mixture was stirred and mixed at 6000 min-1 for 5 minutes using a homogenizer to prepare a monomer emulsion. In a separate container, 0.1 part of 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.) Was dissolved in water to prepare a 10% initiator aqueous solution.

Next, in a reaction vessel equipped with a cooling pipe, a nitrogen introducing pipe, a thermometer and a stirrer, 52.3 parts of water, 30% amount of 10% initiator aqueous solution prepared as described above, monomer emulsion prepared as described above Was added, and the emulsion polymerization was carried out at 59 ° C. for 1 hour while stirring. Then, all of the remaining 10% initiator aqueous solution (70% amount) was added, and then all of the remaining monomer emulsion (80% amount) was added over 3 hours with stirring. The reaction was performed for 3 hours. Next, this was cooled to 30 ° C. or lower and adjusted to pH 8 by adding 10% ammonia water to obtain a water-dispersed acrylic pressure-sensitive adhesive.
(Formation of adhesive layer)
A water-dispersed acrylic pressure-sensitive adhesive was coated on a release film (polyethylene terephthalate base material, Diafoil MRF38, manufactured by Mitsubishi Chemical Polyester Co., Ltd.) so that the thickness after drying was 21 μm, It dried for 2 minutes at 100 degreeC with the hot-air circulation type oven, and formed the adhesive layer on the release film.
(Preparation of optical film)
A polyvinyl alcohol film (thickness 80 μm) is stretched 5 times the original length in an aqueous iodine solution at 40 ° C., and then the polyvinyl alcohol film is pulled up from the aqueous iodine solution and dried at 50 ° C. for 4 minutes to obtain a polarizer. Obtained. A triacetyl cellulose film as a transparent protective film was adhered to both sides of the polarizer using a polyvinyl alcohol adhesive to obtain an optical film.

Example 1
Epocross WS-700 (oxazoline group-containing acrylic polymer, manufactured by Nippon Shokubai Co., Ltd.) is diluted with water / ethanol (volume ratio 1: 1) to a solid content of 2% to prepare a primer solution. did. This primer solution was coated on one side of an optical film using a Mayer bar # 5 and dried at 40 ° C. for 2 minutes to provide a primer layer. Subsequently, the release film in which the adhesive layer was formed was bonded to the single side | surface of the optical film in which the undercoat layer was provided, and the adhesive optical film was produced.

Example 2
Except for changing the undercoat solution Epocros WS-700 (oxazoline group-containing acrylic polymer, manufactured by Nippon Shokubai Co., Ltd.) to Epocros WS-500 (oxazoline group-containing acrylic polymer, manufactured by Nippon Shokubai Co., Ltd.) A pressure-sensitive adhesive optical film was produced in the same manner as in Example 1.

Example 3
A pressure-sensitive adhesive optical film was produced in the same manner as in Example 1 except that the solid content of the primer solution was changed from 2% to 5%.
Reference example 1
In the preparation of the primer solution of Example 1, Epocros WS-700 (oxazoline group-containing acrylic polymer, manufactured by Nippon Shokubai Co., Ltd.) of the primer solution was changed to Epocros WS-700 (oxazoline group-containing acrylic polymer, ) Manufactured by Nippon Shokubai) and Polyment SK-1000 (ethyleneimine-modified acrylic polymer, manufactured by Nippon Shokubai Co., Ltd.) (mixing ratio is 5:95 in terms of solid content), water / A primer coating solution was prepared in the same manner as in Example 1 except that the ethanol (volume ratio of 1: 1) mixed solution was changed to water to prepare an adhesive optical film.

Reference example 2
In the preparation of the primer solution of Example 1, Epocros WS-700 (oxazoline group-containing acrylic polymer, manufactured by Nippon Shokubai Co., Ltd.) of the primer solution was changed to Epocros WS-700 (oxazoline group-containing acrylic polymer, ) Manufactured by Nippon Shokubai Co., Ltd.) and poise 532A (acrylic acid / maleic acid copolymer ammonium salt, number average molecular weight of about 10,000, manufactured by Kao Corporation) (mixing ratio is 95: 5 in solid content ratio) Except that the water / ethanol (volume ratio of 1: 1) mixed solution was changed to water, and the same treatment as in Example 1 was carried out to prepare a primer solution to produce an adhesive optical film. did.

Reference example 3
In the preparation of the primer solution of Example 1, Epocros WS-700 (oxazoline group-containing acrylic polymer, manufactured by Nippon Shokubai Co., Ltd.) of the primer solution was changed to Epocros WS-700 (oxazoline group-containing acrylic polymer, ) Manufactured by Nippon Shokubai Co., Ltd., Polyment SK-1000 (ethyleneimine modified acrylic polymer, manufactured by Nippon Shokubai Co., Ltd.), Poise 532A (acrylic acid / maleic acid copolymer ammonium salt, number average molecular weight of about 10,000, Kao ( Except that the water / ethanol (volume ratio is 1: 1) mixed solution was changed to water. In the same manner as in Example 1, a primer solution was prepared, and an adhesive optical film was produced.

Example 4
A pressure-sensitive adhesive optical film was produced in the same manner as in Example 1 except that the solid content of the primer solution was changed from 2% to 0.25%.
Comparative Example 1
Except for changing the undercoat solution Epocros WS-700 (oxazoline group-containing acrylic polymer, manufactured by Nippon Shokubai Co., Ltd.) to water-dispersed urethane resin Takelac W-511 (Mitsui Takeda Chemical Co., Ltd.) In the same manner as in No. 1, an adhesive optical film was produced.

Comparative Example 2
Example 1 except that Epocross WS-700 (oxazoline group-containing polymer, manufactured by Nippon Shokubai Co., Ltd.) of the primer solution was changed to water-dispersed polyester resin Byron TAD-1000 (manufactured by Toyobo Co., Ltd.) In the same manner as above, an adhesive optical film was produced.
Comparative Example 3
Example 1 except that Epocros WS-700 (oxazoline group-containing polymer, manufactured by Nippon Shokubai Co., Ltd.) as the primer solution was changed to a water-dispersed vinyl acetate resin Boncoat 9180 (produced by Dainippon Ink, Inc.). In the same manner as above, an adhesive optical film was produced.

Comparative Example 4
Except for changing the undercoat solution Epocross WS-700 (oxazoline group-containing acrylic polymer, manufactured by Nippon Shokubai Co., Ltd.) to carbodiimide group-containing water-dispersed acrylic resin Carbodilite E-01 (manufactured by Nisshinbo Co., Ltd.) A pressure-sensitive adhesive optical film was produced in the same manner as in Example 1.

Comparative Example 5
In the preparation of the primer solution of Example 1, Epocross WS-700 (oxazoline group-containing acrylic polymer, manufactured by Nippon Shokubai Co., Ltd.) of the primer solution was replaced with Poliment SK-1000 (ethyleneimine modified acrylic polymer, ) Produced by Nippon Shokubai Co., Ltd., and treated in the same manner as in Example 1 except that the water / ethanol (volume ratio of 1: 1) mixed solution was changed to water to prepare a primer solution, and an adhesive type An optical film was produced.

Comparative Example 6
A pressure-sensitive adhesive optical film was produced in the same manner as in Example 1 except that no undercoat layer was provided.
(Evaluation)
1) Thickness of undercoat layer In each example , each reference example, and each comparative example, an adhesive optical film provided with only an undercoat layer was dyed with a 2% aqueous ruthenium acid solution for 2 minutes, and this was then placed in an epoxy resin. By embedding and cutting with an ultramicrotome (Ultracut S, manufactured by Leica) to a thickness of about 80 nm, and then observing the cross section of this optical film section with TEM (Hitachi H-7650 acceleration voltage 100 kV), the thickness of the undercoat layer Asked. The results are shown in Table 1.
2) Haze In each example , each reference example, and each comparative example, the optical film provided with only the undercoat layer was cut into 50 × 50 mm, and haze was measured with a haze computer HZ-1 (Suga Test Instruments Co., Ltd.). It was measured. The results are shown in Table 1. In addition, it is preferable that a haze is 2.0% or less normally, and when it exceeds 2%, it looks white visually and is not preferable.
3) Adhesive force between the pressure-sensitive adhesive layer and the optical film The pressure-sensitive adhesive optical films of each Example , each Reference Example and each Comparative Example were cut into a size of 25 × 120 mm and used as a sample. This sample was aged at 23 ° C. in an atmosphere of 60% RH, in an atmosphere of 50 ° C., and in an atmosphere of 90% RH at 60 ° C., respectively. After aging, the release film is peeled off, a polypropylene porous membrane is attached to the adhesive surface of the sample, and an adhesive tape (No. 31B, manufactured by Nitto Denko Corporation) is attached onto the polypropylene porous membrane. After reinforcement, the substrate was left in an atmosphere of 23 ° C. and 60% RH for 24 hours or more. Thereafter, a SUS304 steel plate was attached to the back surface of the adhesive optical film after being left using a double-sided tape, and a polypropylene porous film and an adhesive tape (No. 31B) at a speed of 300 mm / min in a 180 ° direction by a tensile tester. ) And the pressure sensitive adhesive layer was confirmed to adhere to the polypropylene porous membrane side, and then the peel stress was measured. The results are shown in Table 1. In addition, it is preferable that adhesive force is 5.0 N / 25mm or more normally.
4) Heat resistance The adhesive optical films of each Example , each Reference Example and each Comparative Example were cut into a size of 230 × 310 mm and used as a sample. The pressure-sensitive adhesive surface of the sample was attached to a glass plate (thickness 0.7 mm, Corning # 1737, manufactured by Corning Co., Ltd.) and allowed to stand in an atmosphere of 50 ° C. and 0.5 MPa for 15 minutes. Then, the presence or absence of peeling of the adhesive optical film after storing this sample at 90 ° C. for 500 hours was confirmed by visual observation. The results are shown in Table 1.

In Table 1, “◯” indicates that there was no defect such as lifting or peeling, “Δ” indicates that there was peeling of less than 1 mm, and “×” indicates that there was peeling of 1 mm or more. It shows that.
5) Humidity and heat resistance The adhesive optical films of each Example , each Reference Example and each Comparative Example were cut into a size of 230 × 310 mm and used as a sample. The pressure-sensitive adhesive surface of the sample was attached to a glass plate (thickness 0.7 mm, Corning # 1737, manufactured by Corning) and allowed to stand in an atmosphere of 50 ° C. and 0.5 MPa for 15 minutes. Then, the presence or absence of peeling of the adhesive optical film after storing this sample at 60 ° C. and 90% RH for 500 hours was confirmed by visual observation. The results are shown in Table 1.

  In Table 1, “◯” indicates that there was no defect such as lifting or peeling, “Δ” indicates that there was peeling of less than 1 mm, and “×” indicates that there was peeling of 1 mm or more. It shows that.

As is clear from Table 1, the adhesive optical films of Examples 1 to 4 and Reference Examples 1 to 3 are Comparative Example 6 in which no undercoat layer is provided, and Comparative Examples 1 to 5 in which other undercoat layers are provided. Compared with this adhesive type optical film, the adhesive force between the pressure-sensitive adhesive layer and the optical film is high, and particularly high adhesive force can be obtained even by aging by heating. Moreover, it turns out that heat resistance is favorable . Also, Comparative Example 5 using a polyamine polymer alone, both resistance to heat and moist heat resistance, while it is slightly better than the Comparative Examples 1 to 4 and 6, further including an oxazoline group-containing acrylic polymer In Example 4 used in combination, it can be seen that not only the heat resistance but also the moist heat resistance is enhanced.

Further, comparing Example 4 where the thickness of the undercoat layer is thin and Examples 1 to 3 where the thickness of the undercoat layer is thick, when the thickness of the undercoat layer is increased, the adhesion is reduced due to aging due to heating and humidification. On the other hand, it can be seen that if the thickness of the undercoat layer is thin, the adhesion does not decrease .

It is an expanded sectional view of one embodiment of the adhesion type optical film of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical film 2 Undercoat layer 3 Adhesive layer 4 Release sheet

Claims (5)

An optical film;
An adhesive layer laminated on at least one side of the optical film;
An undercoat layer interposed between the optical film and the pressure-sensitive adhesive layer,
The pressure-sensitive adhesive layer is made of an acrylic pressure-sensitive adhesive,
The undercoat layer contains only an oxazoline group-containing polymer as a polymer,
The oxazoline group-containing polymer comprises a main chain consisting of acrylic skeleton, Ri oxazoline group-containing acrylic polymer der containing an oxazoline group in a side chain of the main chain,
The oxazoline group-containing polymer is water-soluble and has an oxazoline value of 220 g solid / eq. An adhesive optical film characterized by the following . The pressure-sensitive adhesive optical film according to claim 1, wherein the undercoat layer is made of a water-dispersed polymer. The acrylic pressure-sensitive adhesive, characterized in that is water-dispersible, pressure-sensitive adhesive optical film according to claim 1 or 2. The pressure-sensitive adhesive layer according to any one of claims 1 to 3 , wherein the pressure-sensitive adhesive layer contains a functional group that reacts with an oxazoline group . The pressure-sensitive adhesive optical film according to claim 4 , wherein the functional group that reacts with an oxazoline group is a carboxyl group.

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