JP5624448B2 - Water-dispersed pressure-sensitive adhesive composition, pressure-sensitive adhesive layer, pressure-sensitive adhesive member, and image display device - Google Patents

Description

  The present invention relates to a water-dispersed pressure-sensitive adhesive. The present invention also relates to an adhesive layer formed from the water-dispersed adhesive, and an adhesive member in which the adhesive layer is laminated on a support substrate.

  The water-dispersed pressure-sensitive adhesive of the present invention can be applied in various applications. For example, as described above, it can be used as a pressure-sensitive adhesive member provided as a pressure-sensitive adhesive layer on one side or both sides of a support substrate. It can be used as a double-sided pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer on both surfaces of a material-less double-sided pressure-sensitive adhesive layer or a supporting substrate. As a base material in an adhesive member, an optical film, a surface protection film base material, a separator, etc. can be used, for example. As the optical film, a polarizing plate, a retardation plate, an optical compensation film, a brightness enhancement film, a surface treatment film such as an antireflection film, a prism sheet, a transparent conductive film used for a touch panel, and these are laminated. There are things that are. In particular, the pressure-sensitive adhesive member in which the pressure-sensitive adhesive layer is formed using an optical film as a supporting substrate is useful as a pressure-sensitive adhesive optical film, and includes image display devices such as liquid crystal display devices, organic EL display devices, CRTs, PDPs, and the like. It is used for a member used with an image display device such as a face plate. Examples of the surface protective film include various plastic films applied to the optical film and the like.

  In liquid crystal display devices and organic EL display devices, for example, in liquid crystal display devices, it is indispensable to dispose polarizing elements on both sides of the liquid crystal cell, and generally polarizing plates are attached. Has been. In addition to polarizing plates, various optical elements have been used for display panels such as liquid crystal panels and organic EL panels in order to improve the display quality of displays. Further, a front plate is used to protect an image display device such as a liquid crystal display device, an organic EL display device, a CRT, or a PDP, to give a high-class feeling, or to differentiate a design. For members used together with image display devices such as liquid crystal display devices and organic EL display devices, and front display plates, for example, retardation plates for preventing coloring, and for improving the viewing angle of liquid crystal displays A viewing angle widening film, a brightness enhancement film for increasing the contrast of a display, a hard coat film used for imparting scratch resistance to the surface, an anti-glare treatment film for preventing reflection on an image display device, Surface treatment films such as antireflection films such as reflective films and low reflective films are used. These films are collectively called optical films.

  When the optical film is attached to a display panel such as a liquid crystal cell and an organic EL panel or a front plate, an adhesive is usually used. Also, the adhesion between the optical film and the display panel such as the liquid crystal cell and the organic EL panel, or the front plate, or the optical film is usually in close contact with each other using an adhesive to reduce the loss of light. Yes. In such a case, an adhesive optical film provided in advance as an adhesive layer on one side of the optical film is generally used because it has the merit that a drying step is not required to fix the optical film. It is done. Moreover, the adhesive layer is provided also in the surface protection film used in order to protect an optical film etc.

  Conventionally, as a pressure-sensitive adhesive used for forming a pressure-sensitive adhesive layer according to the above-mentioned use, an organic solvent-type pressure-sensitive adhesive using an organic solvent as a solvent has been used because it is easy to realize a high-quality coating appearance.

  On the other hand, in recent years, it has been desired to reduce the use of organic solvents from the viewpoint of environmental impact, and water dispersion in which adhesive components are dispersed in water using water as a dispersion medium from organic solvent-type adhesives. Conversion to mold adhesive is desired. Since the water-dispersed adhesive generally contains a surfactant such as an emulsifier as a water-soluble dispersion stabilizing component, the adhesive layer formed with the water-dispersed adhesive is an adhesive formed with an organic solvent-based adhesive. Compared with the agent layer, the initial adhesive force was not sufficient.

  In order to improve the initial adhesive strength of the pressure-sensitive adhesive layer formed of the water-dispersed pressure-sensitive adhesive, it has been proposed that the water-dispersed pressure-sensitive adhesive contains a dispersant mainly composed of polycarboxylic acid or a salt thereof. (Patent Document 1). According to Patent Document 1, although the initial adhesive force of the pressure-sensitive adhesive layer formed of the water-dispersed pressure-sensitive adhesive is improved, further improvement in the initial adhesive force is desired in various applications.

JP 2007-56248 A

  An object of this invention is to provide the water-dispersed adhesive which can form the adhesive layer excellent in the initial adhesive force. Another object of the present invention is to provide a pressure-sensitive adhesive layer formed from the water-dispersed pressure-sensitive adhesive layer.

  Moreover, this invention aims at providing the adhesive member which has the said adhesive layer, and also providing the image display apparatus using the said adhesive member.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by the following water-dispersed pressure-sensitive adhesive composition and the like, and have completed the present invention.

That is, the present invention contains (meth) acrylic acid alkyl ester as a monomer unit, and has a glass transition temperature (however, the glass transition temperature is calculated based on the monofunctional monomer in the monomer unit) of −55 ° C. or higher. Water-dispersed (meth) acrylic copolymer (A) at 0 ° C. or lower,
Water dispersion containing (meth) acrylic acid alkyl ester as a monomer unit and having a glass transition temperature (however, the glass transition temperature is calculated based on a monofunctional monomer in the monomer unit) of 0 ° C. or higher and 180 ° C. or lower. An aqueous dispersion containing a (meth) acrylic copolymer (B) of a mold and a water-soluble resin (C),
At least one of the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) contains a carboxyl group-containing monomer as a monomer unit,
The difference between the glass transition temperature of the (meth) acrylic copolymer (A) and the glass transition temperature of the (meth) acrylic copolymer (B) is 50 ° C. or more, and
The mixing ratio of the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) is (A) / (B) = 50 to 95/5 to 50 (solid content weight ratio). It is related with the water dispersion-type adhesive composition characterized by consisting of the aqueous dispersion which is the range of these.

  In the water-dispersed pressure-sensitive adhesive composition, the water-soluble resin (C) is preferably a water-soluble resin having a carboxyl group salt.

  In the water-dispersed pressure-sensitive adhesive composition, the water-soluble resin (C) has a ratio of the (meth) acrylic copolymer (A) and (meth) acrylic copolymer (B) in terms of solid weight. It is preferable that it is 0.5-15 weight part with respect to a total of 100 weight part.

  In the water-dispersed pressure-sensitive adhesive composition, the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) have either one copolymer in the same emulsion particle. A core layer and the one containing emulsion particles having a core-shell structure in which the other copolymer is present as a shell layer can be used. The core layer is preferably a (meth) acrylic copolymer (B) and the shell layer is preferably a (meth) acrylic copolymer (A).

  In the water-dispersed pressure-sensitive adhesive composition, the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) are each of the (meth) acrylic copolymer (A). Those derived from the aqueous dispersion and the aqueous dispersion of the (meth) acrylic copolymer (B) can be used.

  In the water-dispersed pressure-sensitive adhesive composition, at least one of the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) is an alkoxysilyl group-containing monomer as a monomer unit. (However, the alkoxysilyl group-containing monomer is excluded from the monofunctional monomer relating to the calculation of the glass transition temperature), and the proportion of the alkoxysilyl group-containing monomer is a (meth) acrylic copolymer. It is preferable that it is 0.001-1 weight% of the total monomer unit of (A) or (meth) acrylic-type copolymer (B).

  The present invention also relates to a pressure-sensitive adhesive layer formed by applying the water-dispersed pressure-sensitive adhesive composition and then drying it.

  In the pressure-sensitive adhesive layer, the (meth) acrylic copolymer (B) is present as a domain in the resin component formed from the (meth) acrylic copolymer (A), and the domain is a maximum portion. The ratio of the domain region having a length of 1 nm to 200 nm is preferably 98% or more.

  The pressure-sensitive adhesive layer preferably has an adhesive force of 5 N / 25 mm or more with respect to a glass plate at a 180 ° peeling method, a temperature of 23 ° C., and a peeling speed of 300 mm / min.

  In the present invention, the pressure-sensitive adhesive member is characterized in that the pressure-sensitive adhesive layer is laminated on at least one side of the support base material.

  The present invention also relates to an image display device using at least one of the pressure-sensitive adhesive layer or the pressure-sensitive adhesive member.

  In the present invention, as a water-dispersed pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer, in addition to a water-dispersed (meth) acrylic copolymer (A) having a normal low glass transition temperature, a predetermined high glass A water-dispersed (meth) acrylic copolymer (B) having a transition temperature is contained as a base polymer, and a water-soluble resin (C) is contained. In the pressure-sensitive adhesive layer formed by the water-dispersed pressure-sensitive adhesive composition, the water-dispersed (meth) acrylic copolymer (B) is a resin formed from the (meth) acrylic copolymer (A). In, it can exist in the state which formed the domain. By adding the water-soluble resin (C) to such a structure, the water-dispersed (meth) acrylic copolymer (A) having a normal low glass transition temperature is simply added to the water-soluble resin (A). A pressure-sensitive adhesive layer having a higher initial adhesive force than that of the water-dispersed pressure-sensitive adhesive composition to which C) was added could be realized.

  In addition, since the pressure-sensitive adhesive layer formed of the water-dispersed pressure-sensitive adhesive composition of the present invention contains the water-soluble resin (C), it has good durability in a high-temperature and high-humidity environment, and is a high-temperature and high-humidity environment. The cloudiness of the adhesive layer below can be suppressed. The pressure-sensitive adhesive layer formed of the water-dispersed pressure-sensitive adhesive composition absorbs a large amount of moisture while being stored in a high-temperature and high-humidity environment, and when the environment returns from room temperature to room temperature, The moisture absorbed by the pressure-sensitive adhesive layer causes condensation of water molecules in the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer cannot absorb or dissolve water. As a result, it was investigated that the moisture was deposited in the pressure-sensitive adhesive layer, resulting in dew condensation, which was the cause of the clouding phenomenon. Since the water-dispersed pressure-sensitive adhesive composition of the present invention contains a water-soluble resin (C), it is a highly hygroscopic pressure-sensitive adhesive layer. By using such a highly hygroscopic pressure-sensitive adhesive layer, in the present invention, even when the pressure-sensitive adhesive layer is returned from a high-temperature and high-humidity environment to a room temperature environment, condensation due to moisture precipitation is maintained by maintaining a sufficient hygroscopic function. It is thought that it can suppress so that a cloudiness phenomenon may not occur. The reason why the water-soluble resin exhibits an excellent white turbidity suppressing effect is not clear, but the (meth) acrylic copolymer (A) as a base polymer and the (meth) acrylic copolymer (B) existing as a domain This is presumably because the water-soluble resin (C) exists uniformly between the particles and acts as a microscopic water absorbing site effective in suppressing condensation.

  The water-dispersed pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer of the present invention comprises a water-dispersed (meth) acrylic copolymer (A) having a glass transition temperature of −55 ° C. or higher and 0 ° C. or lower, and a glass transition temperature. Is an aqueous dispersion containing a water-dispersed (meth) acrylic copolymer (B) having a temperature of from 0 ° C. to 180 ° C.

  As described above, the glass transition temperature of the (meth) acrylic copolymer (A) is −55 ° C. or more and 0 ° C. or less. In this range, the cohesive force is reduced while ensuring the adhesiveness of the pressure-sensitive adhesive. Can be suppressed. The glass transition temperature is preferably −20 ° C. or lower, more preferably −30 ° C. or lower, further −35 ° C. or lower, and further preferably −40 ° C. or lower. When the glass transition temperature of the (meth) acrylic copolymer (A) exceeds 0 ° C., the adhesiveness as a pressure-sensitive adhesive is lowered and peeling is likely to occur. On the other hand, the glass transition temperature is preferably −50 ° C. or higher, more preferably −45 ° C. or higher (preferably higher than −45 ° C.). When the glass transition temperature of the (meth) acrylic copolymer (A) is less than −55 ° C., the cohesive force of the pressure-sensitive adhesive is reduced and peeling is likely to occur.

  As described above, the glass transition temperature of the (meth) acrylic copolymer (B) is 0 ° C. or higher and 180 ° C. or lower. In this range, the decrease in cohesive force is suppressed while ensuring the adhesiveness of the pressure-sensitive adhesive. be able to. The glass transition temperature is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, further 70 ° C. or higher, further 80 ° C. or higher, and more preferably 85 ° C. or higher. When the glass transition temperature of the (meth) acrylic copolymer (B) is less than 50 ° C., the cohesive force of the pressure-sensitive adhesive is reduced and peeling is likely to occur. On the other hand, the glass transition temperature is preferably 110 ° C. or less, more preferably 100 ° C. or less, and further preferably 90 ° C. or less (preferably less than 90 ° C.) from the viewpoint of suppressing humidification peeling.

  The difference between the glass transition temperature of the (meth) acrylic copolymer (A) and the glass transition temperature of the (meth) acrylic copolymer (B) is 50 ° C. or more. The difference in the glass transition temperature is 70 ° C. or more, further 80 ° C. or more, further 90 ° C. or more, further 100 ° C. or more, further 110 ° C. or more, and further 120 ° C. or more. This is preferable from the viewpoint of suppressing a decrease in cohesive force while ensuring adhesiveness.

The glass transition temperature of the (meth) acrylic copolymer (A) and the glass transition temperature of the (meth) acrylic copolymer (B) are determined from the monomer units constituting each polymer and their proportions, based on the FOX. It is a theoretical value calculated by the formula:
Formula of FOX: 1 / Tg = w ₁ / Tg ₁ + w ₂ / Tg ₂ +... + W _n / Tg _n
(Tg: Glass transition temperature (K) of polymer, Tg ₁ , Tg ₂ ,... Tg _n : Glass transition temperature (K) of homopolymer of each monomer, w ₁ , w ₂ ,... W _n : (Weight fraction of each monomer)
However, the glass transition temperature of the (meth) acrylic polymer (A) and the glass transition temperature of the (meth) acrylic copolymer (B) are calculated based on the monofunctional monomer. That is, even in the case where each polymer contains a polyfunctional monomer as a constituent monomer unit, the amount of the polyfunctional monomer used is small, and the glass transition temperature of the copolymer is small. Not included in temperature calculation. Moreover, since the alkoxysilyl group-containing monomer is recognized as a polyfunctional monomer, it is not included in the calculation of the glass transition temperature. The theoretical glass transition temperature obtained from the FOX equation is in good agreement with the measured glass transition temperature obtained by differential scanning calorimetry (DSC), dynamic viscoelasticity, and the like.

  The (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) contain (meth) acrylic acid alkyl ester as a monomer unit and satisfy the glass transition temperature. For example, the type of monomer unit and the component composition are not particularly limited. The (meth) acrylic acid alkyl ester refers to an acrylic acid alkyl ester and / or a methacrylic acid alkyl ester, and (meth) in the present invention has the same meaning.

  The (meth) acrylic acid alkyl ester used in the (meth) acrylic polymer (A) preferably has a water solubility in a certain range from the viewpoint of emulsion polymerization reactivity, and controls the glass transition temperature. It is preferable that the main component is an alkyl acrylate ester having 1 to 18 carbon atoms in the alkyl group. Specific examples of the alkyl acrylate ester include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, Examples include acrylic acid alkyl esters such as n-octyl acrylate, lauryl acrylate, tridecyl acrylate, and stearyl acrylate. These can be used alone or in combination of two or more. Of these, alkyl acrylates having 3 to 9 carbon atoms in the alkyl group such as propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and n-octyl acrylate are preferable. The alkyl acrylate is preferably contained in an amount of 60 to 99.9% by weight of the total monomer units, more preferably 70 to 99.9% by weight, further 80 to 99.9% by weight, and further 80 to 99% by weight. Further, it is preferably 80 to 95% by weight.

  In addition, the (meth) acrylic copolymer (A) preferably has a water solubility within a certain range from the viewpoint of emulsion polymerization reactivity, and since the glass transition temperature is easily controlled, A methacrylic acid alkyl ester having 1 to 18 carbon atoms can be used. Specific examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate. And alkyl methacrylates such as n-octyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, and isobornyl methacrylate. These can be used alone or in combination of two or more. Among these, methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate and the like are preferable. The methacrylic acid alkyl ester is preferably 39.9% by weight or less of the total monomer units, more preferably 30% by weight or less, further 20% by weight or less, further 15% by weight or less, and further 10% by weight or less. Is preferred.

  On the other hand, the (meth) acrylic acid alkyl ester used for the (meth) acrylic copolymer (B) preferably has a water solubility in a certain range from the viewpoint of emulsion polymerization reactivity, and controls the glass transition temperature. Therefore, it is preferable that the alkyl group having 1 to 18 carbon atoms in the above alkyl group is a main component. The alkyl methacrylate can be used alone or in combination of two or more. Specific examples of the methacrylic acid alkyl ester include those similar to the above. Among the examples, methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate and the like are preferable. The alkyl methacrylate is preferably contained in an amount of 60 to 99.9% by weight of the total monomer units, more preferably 70 to 99.9% by weight, further 80 to 99.9% by weight, and further 80 to 99% by weight. Further, it is preferably 80 to 95% by weight.

  In addition, the (meth) acrylic copolymer (B) preferably has a water solubility within a certain range from the viewpoint of emulsion polymerization reactivity, and the glass transition temperature is easily controlled. Acrylic acid alkyl ester having 1 to 18 carbon atoms can be used. The alkyl acrylate ester can be used alone or in combination of two or more. Specific examples of the acrylic acid alkyl ester include those similar to the above. Among these examples, alkyl acrylates having 3 to 9 carbon atoms in the alkyl group such as propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and n-octyl acrylate are preferable. The acrylic acid alkyl ester is preferably 39.9% by weight or less of the total monomer units, more preferably 5 to 30% by weight, and further preferably 5 to 20% by weight.

  In addition, at least one of the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) is a carboxyl group for improving the adhesive property of the pressure-sensitive adhesive and imparting stability to the emulsion. Group-containing monomers are used. Examples of the carboxyl group-containing monomer include those having a radical polymerizable unsaturated double bond such as a carboxyl group and a (meth) acryloyl group, a vinyl group, such as (meth) acrylic acid, itaconic acid, maleic acid, Examples include fumaric acid, crotonic acid, carboxyethyl acrylate, and carboxypentyl acrylate. The carboxyl group-containing monomer may be contained as a monomer unit in either the (meth) acrylic copolymer (A) or the (meth) acrylic copolymer (B), and is contained only in one. However, it is preferably contained in both. The carboxyl group-containing monomer is preferably contained in an amount of 0.1 to 10% by weight of the total monomer units of the (meth) acrylic copolymer (A) or (meth) acrylic copolymer (B), and more preferably 0. It is preferably 5 to 7% by weight, more preferably 1 to 6% by weight.

  In the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B), in addition to the (meth) acrylic acid alkyl ester and the carboxyl group-containing monomer, stabilization of an aqueous dispersion, It is related to unsaturated double bonds such as (meth) acryloyl group or vinyl group for the purpose of improving the adhesiveness of the adhesive layer to the substrate such as an optical film and further improving the initial adhesiveness to the adherend. One or more copolymerization monomers having a polymerizable functional group can be introduced by copolymerization.

  Examples of the copolymerization monomer include alkoxysilyl group-containing monomers. The alkoxysilyl group-containing monomer is a silane coupling agent-based unsaturated monomer having at least one unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having an alkoxysilyl group. The alkoxysilyl group-containing monomer is preferable for imparting a crosslinked structure to the (meth) acrylic copolymer (A) and improving the adhesion to glass.

  Examples of the alkoxysilyl group-containing monomer include alkoxysilyl group-containing (meth) acrylate monomers and alkoxysilyl group-containing vinyl monomers. Examples of the alkoxysilyl group-containing (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 , (Meth) acryloyloxyalkyl-trialkoxysilane such as 3- (meth) acryloyloxypropyl-triisopropoxysilane, 3- (meth) acryloyloxypropyl-tributoxysilane; , (Meth) acryloyloxymethyl-methyldimethoxysilane, (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) acryloyloxy Propyl-ethyldiethoxysilane, 3- (meth) acryloyloxypropyl-ethyldipropoxysilane, 3- (meth) acryloyloxypropyl-ethyldiisopropoxysilane, 3- (meth) acryloyloxypropyl-ethyldibutoxysilane, (Meth) acryloyloxyalkyl-alkyldialkoxysilanes such as 3- (meth) acryloyloxypropyl-propyldimethoxysilane and 3- (meth) acryloyloxypropyl-propyldiethoxysilane, and (meth) acryloyloxy corresponding thereto Alkyl-dialkyl (mono) alkoxysilane and the like can be mentioned. In addition, as an alkoxysilyl group-containing vinyl monomer, for example, vinyltrialkoxysilane such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, etc. Vinylalkyldialkoxysilanes and vinyldialkylalkoxysilanes such as vinylmethyltrimethoxysilane, vinylmethyltriethoxysilane, β-vinylethyltrimethoxysilane, β-vinylethyltriethoxysilane, γ-vinylpropyltrimethoxysilane , Γ-vinylpropyltriethoxysilane, γ-vinylpropyltripropoxysilane, γ-vinylpropyltriisopropoxysilane, γ-vinylpropyltributoxysilane, etc. Other alkyltrialkoxysilane, these correspond and (vinyl) alkyl dialkoxy silanes, and the like (vinyl alkyl) dialkyl (mono) alkoxysilanes.

  The alkoxysilyl group-containing monomer may be contained in either the (meth) acrylic copolymer (A) or the (meth) acrylic copolymer (B), or may be contained only in one. Good. The proportion of the alkoxysilyl group-containing monomer is preferably 0.001 to 1% by weight of the total monomer units of the (meth) acrylic copolymer (A) or (meth) acrylic copolymer (B), Further, it is preferably 0.01 to 0.5% by weight, more preferably 0.02 to 0.1% by weight. If it is less than 0.001% by weight, the effect of using an alkoxysilyl group-containing monomer (addition of a crosslinked structure, adhesion to glass) cannot be sufficiently obtained. On the other hand, if it exceeds 1% by weight, the adhesive layer is crosslinked. The degree becomes too high, and the pressure-sensitive adhesive layer may be cracked over time.

  Moreover, a phosphoric acid group containing monomer is mentioned as a copolymerization monomer. The phosphate group-containing monomer has an effect of improving the adhesion to glass.

Examples of the phosphate group-containing monomer include the following general formula (1):
(In General Formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 1 to 4 carbon atoms, m represents an integer of 2 or more, and M ¹ and M ² are each independently selected. Represents a hydrogen atom or a cation). The phosphoric acid group containing monomer represented by this is mentioned.

  In general formula (1), m is 2 or more, preferably 4 or more and usually 40 or less, and m represents the degree of polymerization of the oxyalkylene group. Examples of the polyoxyalkylene group include a polyoxyethylene group, a polyoxypropylene group, and the like, and these polyoxyalkylene groups may be random, block, or graft units. In addition, the cation according to the salt of the phosphate group is not particularly limited, for example, an alkali metal such as sodium or potassium, for example, an inorganic cation such as an alkaline earth metal such as calcium or magnesium, for example, a quaternary amine And organic cations.

  The proportion of the phosphate group-containing monomer may be contained in either the (meth) acrylic copolymer (A) or the (meth) acrylic copolymer (B), and is contained only in one. Also good. The proportion of the phosphate group-containing monomer is preferably 0.1 to 20% by weight of the total monomer units of the (meth) acrylic copolymer (A) or (meth) acrylic copolymer (B). If it is less than 0.1% by weight, the effect of using a phosphate group-containing monomer (suppression of the generation of linear bubbles) cannot be sufficiently obtained.

  Specific examples of the copolymerizable monomer other than the alkoxysilyl group-containing monomer and the phosphate group-containing monomer include, for example, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; for example, phenyl (meth) acrylate (Meth) acrylic acid aryl esters, for example, vinyl esters such as vinyl acetate and vinyl propionate; for example, styrenic monomers such as styrene; for example, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, etc. Epoxy group-containing monomers; for example, hydroxyl group-containing monomers such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; for example, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl ( (Meth) acrylamide, N- Sopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, (meth) acryloylmorpholine, aminoethyl (meth) acrylate, (meth) acrylic acid Nitrogen atom-containing monomers such as N, N-dimethylaminoethyl and t-butylaminoethyl (meth) acrylate; for example, alkoxy group-containing monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; Cyano group-containing monomers such as acrylonitrile and methacrylonitrile; functional monomers such as 2-methacryloyloxyethyl isocyanate; and olefins such as ethylene, propylene, isoprene, butadiene and isobutylene Monomers, for example, vinyl ether monomers such as vinyl ether; halogen atom-containing monomers such as vinyl chloride; and others such as N-vinyl pyrrolidone, N- (1-methylvinyl) pyrrolidone, N-vinyl pyridine, N-vinyl piperidone , N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, and other N-vinylcarboxylic acids Examples include amides.

  Examples of copolymerizable monomers include maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; for example, N-methylitaconimide, N-ethylitaconimide, N -Itacone imide monomers such as butyl itaconimide, N-octyl itacon imide, N-2-ethylhexyl itacon imide, N- cyclohexyl itacon imide, N- lauryl itacon imide; Succinimide monomers such as (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyoctamethylene succinimide; for example, styrene sulfonic acid, Examples include sulfonic acid group-containing monomers such as aryl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, and (meth) acryloyloxynaphthalene sulfonic acid. .

  In addition, as the copolymerizable monomer, for example, glycol-based acrylic ester monomers such as polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, and methoxypolypropylene glycol (meth) acrylate Other examples include, for example, tetrahydrofurfuryl (meth) acrylate, a heterocyclic ring such as fluorine (meth) acrylate, and an acrylate monomer containing a halogen atom.

  Furthermore, a polyfunctional monomer other than the alkoxysilyl group-containing monomer can be used as the copolymerizable monomer for adjusting the gel fraction of the water-dispersed pressure-sensitive adhesive composition. Examples of the polyfunctional monomer include compounds having two or more unsaturated double bonds such as a (meth) acryloyl group and a vinyl group. For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetraethylene glycol di (meth) acrylate, etc. (mono or poly) In addition to (mono or poly) alkylene glycol di (meth) acrylates such as ethylene glycol di (meth) acrylate and (mono or poly) propylene glycol di (meth) acrylate such as propylene glycol di (meth) acrylate, neopentyl glycol Di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate Esterified product of (meth) acrylic acid and polyhydric alcohol such as pentaerythritol tri (meth) acrylate and dipentaerythritol hexa (meth) acrylate; polyfunctional vinyl compound such as divinylbenzene; diacetone acrylamide; (meth) acrylic acid Examples thereof include compounds having unsaturated double bonds having different reactivity such as allyl and vinyl (meth) acrylate. In addition, as a polyfunctional monomer, polyester (meta) having two or more unsaturated double bonds such as (meth) acryloyl group and vinyl group as functional groups similar to the monomer component is added to a skeleton such as polyester, epoxy, and urethane. ) Acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and the like can also be used.

  The copolymerizable monomer other than the alkoxysilyl group-containing monomer and the phosphate group-containing monomer is a monomer unit in either the (meth) acrylic copolymer (A) or the (meth) acrylic copolymer (B). Or may be contained only in one side. When these copolymerizable monomers are monofunctional monomers, the ratio is such that the viscosity of the emulsion does not become too high, and from the viewpoint of emulsion stability, the (meth) acrylic copolymer (A) or (meth) It is preferably 20% by weight or less, more preferably 10% by weight or less, and further preferably 5% by weight or less of the total monomer units of the acrylic copolymer (B). When the copolymerizable monomer is a polyfunctional monomer, the ratio is the total monomer of the (meth) acrylic copolymer (A) or (meth) acrylic copolymer (B) from the viewpoint of emulsion stability. It is preferably 5% by weight or less of the unit, more preferably 3% by weight or less, and further preferably 1% by weight or less.

  The water-dispersed pressure-sensitive adhesive composition of the present invention contains the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B). It can be obtained by preparing an aqueous dispersion of an acrylic copolymer (A) and an aqueous dispersion of a (meth) acrylic copolymer (B) and mixing them.

  In the aqueous dispersion of the (meth) acrylic copolymer (A) and the aqueous dispersion of the (meth) acrylic copolymer (B), a monomer component containing a (meth) acrylic acid alkyl ester is used as a surfactant. And by polymerization in water in the presence of a radical polymerization initiator. Examples of the form of polymerization include emulsion polymerization, suspension polymerization, and dispersion polymerization. In the case of emulsion polymerization, a polymer emulsion is used. In the case of suspension polymerization, a polymer suspension is used. In the case of dispersion polymerization, a polymer dispersion is used. can get. The type of adhesive polymer and the polymerization means are selected according to the type of adhesive. In addition, the surfactant is appropriately selected depending on each polymerization mode, and an emulsifier in the case of emulsion polymerization and a dispersant in the case of suspension polymerization.

  As the aqueous dispersion of the (meth) acrylic copolymer (A) and the aqueous dispersion of the (meth) acrylic copolymer (B) in the water-dispersed pressure-sensitive adhesive composition, a polymer obtained by emulsion polymerization An emulsion-type pressure-sensitive adhesive using an emulsion is preferred.

  Moreover, the water-dispersed pressure-sensitive adhesive composition of the present invention comprises the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) in one emulsion particle. The polymer may be contained as emulsion particles having a core-shell structure in which the polymer is present as a core layer and the other copolymer is present as a shell layer.

  The emulsion particles having the core-shell structure include (1) the case where the core layer is a (meth) acrylic copolymer (A) and the shell layer is a (meth) acrylic copolymer (B), and (2) the core The layer may be a (meth) acrylic copolymer (B) and the shell layer may be a (meth) acrylic copolymer (A). The emulsion particles having the core-shell structure of the present invention can employ any of the structures (1) and (2) above. However, the structure (2) is preferable in order to effectively suppress peeling over time.

  The core-shell structure emulsion particles are obtained by multi-stage emulsion polymerization in which the core layer copolymer is formed by emulsion polymerization, and then the shell layer copolymer is emulsion polymerized in the presence of the core layer copolymer. be able to. That is, in each emulsion polymerization, a monomer component containing a (meth) acrylic acid alkyl ester, which is a monomer component related to the monomer unit of the core layer or shell layer copolymer, is converted into a surfactant (emulsifier) and a radical polymerization initiator. A copolymer of the core layer or the shell layer is formed by polymerizing in water in the presence of.

  Emulsion polymerization of the monomer component is performed by emulsion polymerization after emulsifying the monomer component in water by a conventional method. Thus, an aqueous dispersion (polymer emulsion) containing the (meth) acrylic copolymer (A) or the (meth) acrylic copolymer (B) as a base polymer is prepared. In emulsion polymerization, for example, a surfactant (emulsifier), a radical polymerization initiator, and a chain transfer agent, if necessary, are appropriately blended together with the monomer components described above. 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 and the monomer emulsion dropping method, continuous dropping or divided dropping is appropriately selected. These methods can be appropriately combined. Although reaction conditions etc. are selected suitably, it is preferable that polymerization temperature is about 40-95 degreeC, for example, and it is preferable that polymerization time is about 30 minutes-about 24 hours.

  The surfactant (emulsifier) used for emulsion polymerization is not particularly limited, and various surfactants usually used for emulsion polymerization are used. As the surfactant, for example, an anionic surfactant or a nonionic surfactant is used. Specific examples of anionic surfactants include higher fatty acid salts such as sodium oleate; alkyl aryl sulfonates such as sodium dodecylbenzene sulfonate; alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate; polyoxyethylene lauryl Polyoxyethylene alkyl ether sulfate salts such as sodium ether sulfate; Polyoxyethylene alkyl aryl ether sulfate salts such as polyoxyethylene nonylphenyl ether sodium sulfate; Sodium monooctylsulfosuccinate, sodium dioctylsulfosuccinate, polyoxyethylene laurylsulfosuccinate Alkylsulfosuccinic acid ester salts such as sodium acid salt and derivatives thereof; It can be exemplified sodium naphthalene sulfonate formalin condensate; ether sulfates. Specific examples of nonionic surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; polyoxyethylene alkyl such as polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether Sorbitan monolaurate, sorbitan monostearate, sorbitan higher fatty acid esters such as sorbitan trioleate; polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate; polyoxyethylene monolaurate; Polyoxyethylene higher fatty acid esters such as polyoxyethylene monostearate; oleic acid monoglyceride, stearic acid monoglyceride, etc. Can be exemplified polyoxyethylene-polyoxypropylene block copolymers, polyoxyethylene distyrenated phenyl ether; glycerol higher fatty acid esters.

  In addition to the non-reactive surfactant, a reactive surfactant having a radical polymerizable functional group related to an ethylenically unsaturated double bond can be used as the surfactant. As the reactive surfactant, a radical polymerizable surfactant obtained by introducing a radical polymerizable functional group (radical reactive group) such as propenyl group or allyl ether group into the anionic surfactant or nonionic surfactant. Agents and the like. These surfactants are used alone or in combination as appropriate. Among these surfactants, a radical polymerizable surfactant having a radical polymerizable functional group is preferably used from the viewpoint of the stability of the aqueous dispersion and the durability of the pressure-sensitive adhesive layer.

  Specific examples of the anionic reactive surfactant include alkyl ethers (for example, Aqualon KH-05, KH-10, KH-20, manufactured by Asahi Denka Kogyo Co., Ltd. Adekaria soap SR-10N, SR-20N, Latemu PD-104, etc. manufactured by Kao Corporation); Sulfosuccinic acid ester system (for example, Latemul S-120, S-120A, S-180P manufactured by Kao Corporation) S-180A, Sanyo Chemical Co., Ltd., Eleminol JS-2, etc.); alkyl phenyl ether or alkyl phenyl ester (commercially available products include, for example, Aqualon H-2855A, H-3855B, Daiichi Kogyo Seiyaku Co., Ltd., H-3855C, H-3856, HS-05, HS-10, HS-20, HS-30, BC- (5, BC-10, BC-20, Adeka Soap SDX-222, SDX-223, SDX-232, SDX-233, SDX-259, SE-10N, SE-20N) manufactured by Asahi Denka Kogyo Co., Ltd. ) Acrylate sulfate ester (commercially available products include, for example, Antox MS-60, MS-2N, Sanyo Kasei Kogyo Co., Ltd., Elminol RS-30, etc. manufactured by Nippon Emulsifier Co., Ltd.); For example, H-3330PL manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Adeka Soap PP-70 manufactured by Asahi Denka Kogyo Co., Ltd.). Nonionic reactive surfactants include, for example, alkyl ethers (commercially available products such as Adeka Soap ER-10, ER-20, ER-30, ER-40, Kao Corporation, manufactured by Asahi Denka Kogyo Co., Ltd. Latemul PD-420, PD-430, PD-450, etc.); alkyl phenyl ethers or alkyl phenyl esters (commercially available products include, for example, Aqualon RN-10, RN-20, RN manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) -30, RN-50, Adeka Soap NE-10, NE-20, NE-30, NE-40, etc. manufactured by Asahi Denka Kogyo Co., Ltd.); (meth) acrylate sulfate ester type (commercially available products include, for example, Japan Emulsifiers RMA-564, RMA-568, RMA-1114, etc.).

  The blending ratio of the surfactant is preferably 0.3 to 5 parts by weight with respect to 100 parts by weight of the monomer component containing the (meth) acrylic acid alkyl ester. Depending on the blending ratio of the surfactant, adhesion characteristics, polymerization stability, mechanical stability, and the like can be improved. The blending ratio of the surfactant is more preferably 0.3 to 4 parts by weight.

  The radical polymerization initiator is not particularly limited, and a known radical 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, Azo initiators such as 2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride; for example, potassium persulfate, Persulfate-based initiators such as ammonium persulfate; for example, peroxide-based initiators such as benzoyl peroxide, t-butyl hydroperoxide, hydrogen peroxide; for example, substituted ethane-based initiators such as phenyl-substituted ethane; And carbonyl-based initiators such as aromatic carbonyl compounds. These polymerization initiators are suitably used alone or in combination. Moreover, when performing emulsion polymerization, it can be set as the redox-type initiator which uses a reducing agent together with a polymerization initiator depending on necessity. Thereby, it becomes easy to accelerate the emulsion polymerization rate or to perform the emulsion polymerization at a low temperature. Examples of such reducing agents include reducing organic compounds such as metal salts such as ascorbic acid, ersorbic acid, tartaric acid, citric acid, glucose, formaldehyde sulfoxylate; thorium thiosulfate, sodium sulfite, sodium bisulfite, Examples include reducing inorganic compounds such as sodium metabisulfite; ferrous chloride, Rongalite, thiourea dioxide, and the like.

  Further, the blending ratio of the radical polymerization initiator is appropriately selected, and is, for example, about 0.02 to 1 part by weight, preferably 0.02 to 0.5 part by weight, with respect to 100 parts by weight of the monomer component. More preferably, it is 0.08 to 0.3 parts by weight. If it is less than 0.02 part by weight, the effect as a radical polymerization initiator may be reduced. If it exceeds 1 part by weight, a (meth) acrylic copolymer (A) related to an aqueous dispersion (polymer emulsion) (A ) May decrease, and the durability of the water-dispersed pressure-sensitive adhesive composition may decrease. In the case of a redox initiator, the reducing agent is preferably used in the range of 0.01 to 1 part by weight with respect to 100 parts by weight of the total amount of monomer components. As described above, the emulsion particles having the core-shell structure can be obtained by multi-stage emulsion polymerization in which the core layer copolymer is formed by emulsion polymerization and then the shell layer copolymer is emulsion polymerized. At this time, in the emulsion polymerization of the copolymer of the core layer and the emulsion polymerization of the copolymer of the shell layer, the amount of the initiator used relative to the monomer component is the same as described above.

  The chain transfer agent adjusts the molecular weight of the water-dispersed (meth) acrylic polymer as necessary, and a chain transfer agent usually used for emulsion polymerization is usually used. Examples thereof include mercaptans such as 1-dodecanethiol, mercaptoacetic acid, 2-mercaptoethanol, 2-ethylhexyl thioglycolate, 2,3-dimethylcapto-1-propanol, and mercaptopropionic acid esters. These chain transfer agents are appropriately used alone or in combination. Moreover, the mixture ratio of a chain transfer agent is 0.001-0.3 weight part with respect to 100 weight part of monomer components, for example.

  By such emulsion polymerization, the (meth) acrylic copolymer (A) or the (meth) acrylic copolymer (B) can be prepared as an aqueous dispersion (emulsion). Such water-dispersed (meth) acrylic copolymer (A) or (meth) acrylic copolymer (B) has an average particle size of, for example, 0.05 to 3 μm, preferably 0. 0.05 to 1 μm. When the average particle size is smaller than 0.05 μm, the viscosity of the water-dispersed pressure-sensitive adhesive composition may increase. When the average particle size is larger than 1 μm, the adhesion between the particles may decrease and the cohesion may decrease. .

  In order to maintain the dispersion stability of the aqueous dispersion, at least one of the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) according to the aqueous dispersion is The monomer unit contains a carboxyl group-containing monomer, but it is preferable to neutralize the carboxyl group-containing monomer. Neutralization can be performed, for example, with ammonia, alkali metal hydroxide, or the like.

  The water-dispersed (meth) acrylic copolymer (A) or (meth) acrylic copolymer (B) of the present invention preferably has a weight average molecular weight of 1,000,000 or more. In particular, those having a weight average molecular weight of 1,000,000 to 4,000,000 are preferable in terms of heat resistance and moisture resistance. When the weight average molecular weight is less than 1,000,000, heat resistance and moisture resistance are lowered, which is not preferable. Moreover, the pressure-sensitive adhesive obtained by emulsion polymerization is preferable because its molecular weight becomes very high due to its polymerization mechanism. However, since the pressure-sensitive adhesive obtained by emulsion polymerization generally has a large gel content and cannot be measured by GPC (gel permeation chromatography), it is often difficult to support the actual measurement regarding molecular weight.

  The water-dispersed pressure-sensitive adhesive composition of the present invention comprises the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) in a ratio of (A) / (B) = 50. It contains in the range of -95 / 5-50 (solid content weight ratio). The emulsion particles having a core-shell structure are prepared by combining the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) in the same emulsion particle (A) / (B) = It contains in the range of 50-95 / 5-50 (weight ratio). Within this range, by using the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B), it is possible to suppress a decrease in cohesive force while ensuring adhesiveness of the pressure-sensitive adhesive. it can. The said ratio is a ratio when the sum total of each solid content weight of (meth) acrylic-type copolymer (A) and (meth) acrylic-type copolymer (B) is 100 (weight%).

The ratio (solid content weight ratio) of the (meth) acrylic copolymer (A) is 50% by weight or more, preferably 60% by weight or more, and more preferably 70% by weight or more. When the ratio (solid weight ratio) of the (meth) acrylic copolymer (A) is less than 50% by weight, the adhesive property of the pressure-sensitive adhesive is lowered and peeling is likely to occur. On the other hand, the proportion (solid weight ratio) of the (meth) acrylic copolymer (A) is 95% by weight or less, more preferably 90% by weight or less, further 85% by weight or less, and even less than 85% by weight. It is preferable to use it. If the ratio (solid weight ratio) of the (meth) acrylic copolymer (A) is less than 85% by weight, it does not have monomer units other than the (meth) acrylic acid alkyl ester and the carboxyl group-containing monomer. The effect is good. When the ratio liquid (solid content weight ratio) of the (meth) acrylic copolymer (A) exceeds 95% by weight, the cohesive force of the pressure-sensitive adhesive is lowered and peeling is likely to occur. In the present invention, the solid content weights of the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) are the prepared (meth) acrylic copolymer (A) and Based on the value obtained from the aqueous dispersion of the (meth) acrylic copolymer (B).

  The water-dispersed pressure-sensitive adhesive composition of the present invention contains a water-soluble resin (C) in addition to the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B). The water-soluble resin (C) is mixed with the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B), the appearance when the pressure-sensitive adhesive layer is formed, the color, From the viewpoint of durability and the like, the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) are dispersed in water and mixed in an aqueous medium. In preparing the water-dispersed pressure-sensitive adhesive composition, those capable of forming a stable dispersion without causing aggregation particularly in a neutral to basic pH range are preferred.

  “Water-soluble” in the water-soluble resin (C) means that the solubility in 100 g of water at 25 ° C. is 5 g or more. The solubility of the water-soluble resin (C) in 100 g of water is preferably 10 to 50 g.

  Examples of the water-soluble resin (C) include polymers or copolymers obtained by polymerizing at least one of carboxyl group-containing monomers, hydroxyl group-containing monomers, vinyl pyrrolidone, acrylamide and other hydrophilic monomers. It is done. Examples of the carboxyl group-containing monomer and the hydroxyl group-containing monomer are the same as those exemplified as the copolymerization monomer unit of the (meth) acrylic polymer.

  Moreover, as water-soluble resin (C), the copolymer of the said hydrophilic monomer and another copolymerizable monomer is mentioned. Other copolymerizable monomers that can be copolymerized with the hydrophilic monomer include alkyl (meth) having an alkyl group having 4 to 14 carbon atoms exemplified as the main component of the (meth) acrylic copolymer. In addition to acrylate alkyl, there can be exemplified copolymerizable monomers other than the above hydrophilic monomers exemplified as copolymer monomer units of the (meth) acrylic polymer, for example, styrene monomers; olefin monomers; Examples thereof include methyl vinyl ether.

  Specific examples of the water-soluble resin obtained by polymerization or copolymerization of the hydrophilic monomer include, for example, polycarboxylic acid such as poly (meth) acrylic acid obtained by polymerizing a carboxyl group-containing monomer such as (meth) acrylic acid. (Meth) acrylic acid- (meth) acrylic acid alkyl ester copolymer, (meth) methacrylic acid, which is a copolymer of an acid polymer, a carboxyl group-containing monomer such as (meth) acrylic acid and other monomers / (Meth) acrylic acid alkyl ester copolymer, (meth) methacrylic acid / acrylamide / (meth) acrylic acid alkyl ester copolymer; styrene / maleic anhydride copolymer, isobutylene / maleic anhydride copolymer , Acrylamide / (meth) acrylic acid alkyl ester copolymer, polyacrylamide, polyvinyl Pyrrolidone, methyl vinyl ether.

  Among the water-soluble resins obtained by polymerization or copolymerization of the hydrophilic monomer, those containing a carboxyl group-containing monomer as a monomer unit, that is, a water-soluble resin containing a carboxyl group is all or one of the carboxyl groups. What the part forms the salt of a carboxyl group is preferable. The salt of the carboxyl group can be carried out by neutralizing the carboxyl group by adding a water-soluble basic component to the water-soluble resin. As the water-soluble basic component, the same water-soluble (meth) acrylic polymer as that used for neutralization of the carboxyl group of the (meth) acrylic polymer can be used. Examples of the cation forming the carboxyl group salt of the water-soluble resin include inorganic cations such as alkali metals such as sodium and potassium, alkaline earth metals such as calcium and magnesium, and organic such as tertiary amines. Examples include cations and ammonium cations. Among these, an ammonium cation or a sodium cation is preferable.

  As the water-soluble resin obtained by polymerization or copolymerization of the hydrophilic monomer, the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) are mixed (transparency, dispersion). From the viewpoint of (stability), a water-soluble resin containing a carboxyl group salt is preferred. In particular, poly (meth) acrylic acid salts (especially ammonium salts or sodium salts) and copolymers of (meth) acrylic acid and other monomers (especially ammonium salts or sodium salts) maintain optical properties. From the viewpoint of stability during dispersion.

  Specific products of water-soluble resins containing a carboxyl group salt include, for example, polycarboxylic acid ammonium salt-based dispersants (for example, trade names Dispatex SMA, Rohm and Haas (manufactured by Nikka Chemical Co., Ltd.)) ) Product name Orotan 165A, product name DKS DISCOAT N-14 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., styrene maleic acid resin half ester dispersant (for example, product name ALASTAR manufactured by Arakawa Chemical Industries, Ltd.) 703S). Also, polycarboxylic acid sodium salt-based dispersants (for example, trade names SN Dispersant 5034, Nop Cosperth 44C, manufactured by San Nopco Co., Ltd., trade names Aqualic DL-40, DL-365, Kao manufactured by Nippon Shokubai Co., Ltd., Kao) Trade name Poise 521 manufactured by Co., Ltd., and trade name Epan 785 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). As a trade name of polyvinylpyrrolidone, trade name K-30 manufactured by Nippon Shokubai Co., Ltd. may be mentioned.

  Examples of water-soluble resins other than the above include cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose; polyvinyl alcohol, sodium alginate, gelatin, casein, starch, and derivatives thereof.

  The water-soluble resin (C) preferably has a surface tension of 25 to 80 mN / m in a 1% by weight aqueous solution. Those satisfying the surface tension within this range are preferable because the adhesion to glass is improved. The surface tension is more preferably 60 to 80 mN / m. Those satisfying the surface tension in this range have little cloudiness after being exposed to humidification, and are suitable for the optical field where transparency is required. The higher the surface tension value, the smaller the hydrophobic component of the water-soluble resin (C), that is, the higher the concentration of hydrophilic components such as carboxyl groups, the more effective the adhesiveness.

  The ratio of the water-soluble resin (C) in the water-dispersed pressure-sensitive adhesive composition of the present invention is such that the (meth) acrylic copolymer (A) and (meth) acrylic copolymer ( 0.5-15 weight part is preferable with respect to a total of 100 weight part of B), 0.5-10 weight part is more preferable, Furthermore, 1-10 weight part is preferable. If the proportion of the water-soluble resin (C) is less than 0.5 parts by weight, it is difficult to obtain the effect of initial adhesiveness. On the other hand, if it exceeds 15 parts by weight, the elastic modulus becomes too high and the adhesive force tends to decrease. Become.

  The water-dispersed pressure-sensitive adhesive composition of the present invention is water containing a water-dispersed (meth) acrylic copolymer (A), a (meth) acrylic copolymer (B), and a water-soluble resin (C). The water-soluble resin (C) is blended with an aqueous dispersion containing a water-dispersed (meth) acrylic copolymer (A) and a (meth) acrylic copolymer (B). Can be prepared. In addition, the water-dispersed pressure-sensitive adhesive composition of the present invention is an aqueous dispersion containing the water-dispersed (meth) acrylic copolymer (A) and / or (meth) acrylic copolymer (B). In the process of preparing the water-dispersed (meth) acrylic copolymer (as a raw material monomer used during emulsion polymerization), the hydrophilic monomer is used in a range that does not impair the dispersion stability during emulsion polymerization. A) and / or (meth) acrylic copolymer (B) can be produced, and separately prepared by simultaneously forming water-soluble resin (C) by side reaction.

  As the hydrophilic monomer used when forming the water-soluble resin (C) together with the production of the water-dispersed (meth) acrylic copolymer (A) and / or (meth) acrylic copolymer (B) Are preferably a carboxyl group-containing monomer, a hydroxyl group-containing monomer, N-vinylpyrrolidone, (meth) acrylamide and the like. Usually, in addition to the carboxyl group-containing monomer, a carboxyl group-containing monomer is used in the production of the water-dispersed (meth) acrylic copolymer (A) and / or the (meth) acrylic copolymer (B). As the hydrophilic monomer, it is preferable to use a hydroxyl group-containing monomer, N-vinylpyrrolidone, or the like. Using a hydroxyl group-containing monomer or N-vinylpyrrolidone, water-soluble resin (C) together with the production of water-dispersed (meth) acrylic copolymer (A) and / or (meth) acrylic copolymer (B) In general, the hydroxyl group-containing monomer and N-vinylpyrrolidone are preferably about 0.2 to 10 parts by weight, and 0.5 to 5 parts by weight with respect to 100 parts by weight of the alkyl (meth) acrylate. It is more preferable to use it.

  The water-dispersed pressure-sensitive adhesive composition of the present invention includes the water-dispersed (meth) acrylic copolymer (A) and (meth) acrylic copolymer (B), and the water-soluble resin (C). The total of the solid content weight of each of these aqueous dispersions is 80% by weight or more of the solid content of the aqueous dispersion according to the water-dispersed pressure-sensitive adhesive composition, and further 90% by weight. % Or more, preferably 95% by weight or more, more preferably 100%. That is, the aqueous dispersion according to the water-dispersed pressure-sensitive adhesive composition includes (meth) acrylic copolymer (A), (meth) acrylic copolymer (B), and water-soluble resin (C). In addition, other components can be used. The proportion of other components is preferably 10% by weight or less from the viewpoint of suppressing the haze deterioration of the pressure-sensitive adhesive layer.

  The water-dispersed pressure-sensitive adhesive composition of the present invention contains water-dispersed (meth) acrylic copolymer (A) and (meth) acrylic copolymer (B) as emulsion particles having a core-shell structure. In the case of preparing the emulsion particles having the core-shell structure, the emulsion of the (meth) acrylic copolymer (A), which was not involved in the core-shell structure, was prepared. , An emulsion of (meth) acrylic copolymer (B) may be formed. Therefore, the water-dispersed pressure-sensitive adhesive composition of the present invention includes an emulsion of (meth) acrylic copolymer (A) and an emulsion of (meth) acrylic copolymer (B) in addition to the core-shell structure emulsion particles. It may contain.

  As said other component, a crosslinking agent can be contained as needed. As the crosslinking agent used when the water-dispersed pressure-sensitive adhesive composition is a water-dispersed acrylic pressure-sensitive adhesive, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a carbodiimide-based crosslinking agent, Commonly used materials such as metal chelate crosslinking agents can be used. These cross-linking agents have an effect of cross-linking by reacting with a functional group introduced into the (meth) acrylic copolymer (A) by using a functional group-containing monomer.

  The blending ratio of the cross-linking agent is not particularly limited. Usually, the total of the solid content weights of the aqueous dispersion of (meth) acrylic copolymer (A) and (meth) acrylic copolymer (B) is 100. It mix | blends in the ratio of about 10 weight part or less of crosslinking agents (solid content) with respect to a weight part. The blending ratio of the crosslinking agent is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, and further preferably about 0.01 to 2 parts by weight. In addition, although a cohesive force can be provided to an adhesive layer with a crosslinking agent, when a crosslinking agent is used, there exists a tendency for adhesiveness to worsen and to become humid peeling easily.

  Furthermore, the water-dispersed pressure-sensitive adhesive composition of the present invention includes a viscosity modifier, a release modifier, a tackifier, a plasticizer, a softener, glass fiber, glass beads, metal powder, and other inorganic materials as necessary. Fillers made of powder, pigments, colorants (pigments, dyes, etc.), pH adjusters (acids or bases), antioxidants, UV absorbers, silane coupling agents, etc. do not depart from the purpose of the present invention. Various additives can be appropriately used within a range. Moreover, it is good also as an adhesive layer etc. which contain microparticles | fine-particles and show light diffusibility. These additives can also be blended as an emulsion.

  The pressure-sensitive adhesive layer of the present invention is formed from the water-dispersed pressure-sensitive adhesive composition. The pressure-sensitive adhesive layer can be formed by applying the water-dispersed pressure-sensitive adhesive composition to a support substrate and then drying. Various materials can be used for the support substrate, and examples thereof include an optical film, a surface protective film substrate, and a separator (or a release film).

  The pressure-sensitive adhesive member of the present invention is obtained by laminating the pressure-sensitive adhesive layer on one side or both sides of a support base material. The pressure-sensitive adhesive member of the present invention is formed by applying the water-dispersed pressure-sensitive adhesive composition to a support substrate and drying it. In the case where the pressure-sensitive adhesive layer is formed on the release film, the pressure-sensitive adhesive layer is bonded to the support substrate and transferred.

  Various methods are used for the application process of the water-dispersed pressure-sensitive adhesive composition. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples thereof include an extrusion coating method.

  Moreover, in the said application | coating process, the application quantity is controlled so that the adhesive layer formed may become predetermined | prescribed thickness (thickness after drying). The thickness (thickness after drying) of the pressure-sensitive adhesive layer is usually set in the range of about 1 to 100 μm, preferably 5 to 50 μm, and more preferably 10 to 40 μm.

  Next, in forming the pressure-sensitive adhesive layer, the applied water-dispersed pressure-sensitive adhesive composition is dried. The drying temperature is usually about 80 to 170 ° C, preferably 80 to 160 ° C, and the drying time is about 0.5 to 30 minutes, preferably 1 to 10 minutes.

  In the pressure-sensitive adhesive layer of the present invention, the (meth) acrylic copolymer (B) has a maximum length of 1 nm or more and 200 nm in the resin component formed from the (meth) acrylic copolymer (A). It exists as the following domain. When the length of the maximum part of the domain is within the above range, a good initial adhesive force can be obtained. On the other hand, when the length of the maximum part of the domain exceeds 200 nm, the haze of the pressure-sensitive adhesive layer becomes high, depolarization occurs, and it is difficult to use in optical applications. From the above viewpoint, the length of the maximum part of the domain is preferably 5 to 150 nm, and more preferably 10 to 100 nm.

  Based on the (meth) acrylic copolymer (B), the control related to the size of the domain reflects the particle size of the aqueous dispersion of the (meth) acrylic copolymer (B) in the size of the domain. Can be made.

  The ratio of the domain region having the maximum length of 1 nm to 200 nm is preferably 98% or more, and more preferably 100%. Note that the ratio of the domain region related to the length of the maximum portion means that the exceptional maximum domain is excluded when confirming that the length of the maximum portion is 1 nm or more and 200 nm or less.

  The maximum length of the domain is determined by the transmission electron microscope (TEM), and the maximum domain is determined for each photograph taken at three arbitrary locations (photo image size: size 300 nm × 300 nm to 5000 nm × 5000 nm). And the length of the largest part of the domain having the largest length among the largest domains of the three photographed photographs. In order to exclude the maximal domain, a TEM image having three or more domains of 1 nm or more and 200 nm or less is adopted, and two or less domains are not adopted.

  Further, the pressure-sensitive adhesive layer of the present invention has a haze value of 1% or less when the thickness of the pressure-sensitive adhesive layer is 23 μm and can satisfy 0 to 1%, and is required for a pressure-sensitive adhesive layer for optical films. It has transparency. The haze value is preferably 0 to 0.8%, and more preferably 0 to 0.5%. If the haze value exceeds 1%, depolarization occurs, which is not preferable for optical film applications.

  The pressure-sensitive adhesive layer of the present invention can satisfy an adhesive force of 5 N / 25 mm or more with a 180 ° peeling method, a temperature of 23 ° C., and a peeling speed of 300 mm / min. When it has 5N / 25mm or more as said adhesive force, it is preferable when maintaining the adhesive force with respect to glass, and satisfying durability. The adhesive strength is preferably 5 to 20 N / 25 mm, more preferably 5 to 15 N / 25 mm, and further preferably 5 to 10 N / 25 mm.

  Examples of the constituent material of the release film include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foils, and laminates thereof. However, a plastic film is preferably used from the viewpoint of excellent surface smoothness.

  The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, and a vinyl chloride co-polymer are used. Examples thereof include a polymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

  The release film has a thickness of usually 5 to 200 μm, preferably about 5 to 100 μm. For the release film, if necessary, release and antifouling treatment with a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, etc., coating type, kneading type, An antistatic treatment such as a vapor deposition type can also be performed. In particular, the release property from the pressure-sensitive adhesive layer can be further improved by appropriately performing a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment on the surface of the release film.

  When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a release film until practical use. In addition, said peeling film can be used as a separator of an adhesive member as it is, and can simplify in a process surface.

  Moreover, in order to improve the adhesiveness between the pressure-sensitive adhesive layer on the surface of the support substrate, the pressure-sensitive adhesive layer is formed after forming an anchor layer or performing various easy adhesion treatments such as corona treatment and plasma treatment. Can be formed. Moreover, you may perform an easily bonding process on the surface of an adhesive layer.

  As the material for forming the anchor layer, an anchor agent selected from polyurethane, polyester, polymers containing an amino group in the molecule and polymers containing an oxazolinyl group is preferably used, and an amino group in the molecule is particularly preferably used. And polymers containing an oxazolinyl group. Polymers containing an amino group in the molecule and polymers containing an oxazolinyl group are good because the amino group or oxazolinyl group in the molecule reacts with the carboxyl group in the adhesive or interacts with it such as ionic interactions. Secure adhesion.

  Examples of polymers containing an amino group in the molecule include polymers of amino group-containing monomers such as polyethyleneimine, polyallylamine, polyvinylamine, polyvinylpyridine, polyvinylpyrrolidine, dimethylaminoethyl acrylate, and the like.

  When the support substrate is an optical film, an adhesive optical film is used as the adhesive member. As an optical film, what is used for formation of image display apparatuses, such as a liquid crystal display device, is used, and the kind in particular is not restrict | limited. For example, a polarizing plate is mentioned as an optical film. A polarizing plate having a transparent protective film on one or both sides of a polarizer is generally used.

  The polarizer is not particularly limited, and various types can be used. Examples of polarizers include dichroic iodine and dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. Examples thereof include polyene-based oriented films such as those obtained by adsorbing substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be prepared, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched even in an aqueous solution such as boric acid or potassium iodide or in a water bath.

  As a material constituting the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, cyclic Examples thereof include polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. A transparent protective film is bonded to one side of the polarizer by an adhesive layer. On the other side, as a transparent protective film, (meth) acrylic, urethane-based, acrylurethane-based, epoxy-based, silicone A thermosetting resin such as a system or an ultraviolet curable resin can be used. One or more kinds of arbitrary appropriate additives may be contained in the transparent protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, an anti-coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. . When content of the said thermoplastic resin in a transparent protective film is 50 weight% or less, there exists a possibility that the high transparency etc. which a thermoplastic resin originally has cannot fully be expressed.

  Examples of the optical film include a reflection plate, an anti-transmission plate, a phase difference plate (including wavelength plates such as 1/2 and 1/4), a visual compensation film, a brightness enhancement film, a surface treatment film, and other liquid crystal display devices. What becomes an optical layer which may be used for formation of is mentioned. These can be used alone as an optical film, or can be laminated on the polarizing plate for practical use and used as one layer or two or more layers.

  The surface treatment film is also provided by being bonded to the front plate. Anti-reflective films such as hard coat films used to impart surface scratch resistance, anti-glare treated films to prevent reflection on image display devices, anti-reflective films, low-reflective films, etc. Is mentioned. The front plate is attached to the surface of the image display device in order to protect the image display device such as a liquid crystal display device, an organic EL display device, a CRT, or a PDP, to give a high-class feeling, or to differentiate by design. It is provided together. The front plate is used as a support for the λ / 4 plate in 3D-TV. For example, in a liquid crystal display device, it is provided above the polarizing plate on the viewing side. When the pressure-sensitive adhesive layer of the present invention is used, the same effect as that of the glass substrate can be exhibited not only on the glass substrate but also on a plastic substrate such as a polycarbonate substrate and a polymethylmethacrylate substrate. .

  An optical film in which the optical layer is laminated on a polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of a liquid crystal display device or the like can be improved because of excellent stability and assembly work. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When adhering the polarizing plate and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with the target phase difference characteristic.

  The pressure-sensitive adhesive optical film of the present invention can be preferably used for forming various image display devices such as liquid crystal display devices. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a display panel such as a liquid crystal cell, an adhesive optical film, and an illumination system as required, and incorporating a drive circuit. There is no particular limitation except that the pressure-sensitive adhesive optical film according to the present invention is used. As the liquid crystal cell, any type such as a TN type, STN type, π type, VA type, IPS type, or the like can be used.

  Appropriate liquid crystal display devices such as a liquid crystal display device in which an adhesive optical film is disposed on one side or both sides of a display panel such as a liquid crystal cell, and a lighting system using a backlight or a reflecting plate can be formed. In that case, the optical film by this invention can be installed in the one side or both sides of display panels, such as a liquid crystal cell. When optical films are provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device: OLED) will be described. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light emitting layer, and electron injection layer is known. It has been.

  In organic EL display devices, holes and electrons are injected into the organic light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the phosphor material. Then, light is emitted on the principle that the excited fluorescent material emits light when returning to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. It is used as. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode and the polarizing plate.

  Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, the mirror surface of the metal electrode can be completely shielded by configuring the retardation plate with a quarter-wave plate and adjusting the angle formed by the polarization direction of the polarizing plate and the retardation plate to π / 4. .

  That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. This linearly polarized light becomes generally elliptically polarized light by the phase difference plate, but becomes circularly polarized light particularly when the phase difference plate is a quarter wavelength plate and the angle formed by the polarization direction of the polarizing plate and the phase difference plate is π / 4. .

  This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

  As described above, in the organic EL display device, an elliptically polarizing plate or a circularly polarizing plate in which a retardation plate and a polarizing plate are combined can be used via an adhesive layer in order to block specular reflection. In addition, an elliptical polarizing plate or a circular polarizing plate bonded to the touch panel via an adhesive layer is applied to the organic EL panel without directly bonding the elliptical polarizing plate or the circular polarizing plate to the organic EL panel. be able to.

  As a touch panel applied in the present invention, various methods such as an optical method, an ultrasonic method, a capacitance method, and a resistive film method can be adopted. The resistive touch panel is composed of a touch-side touch panel electrode plate having a transparent conductive thin film and a display-side touch panel electrode plate having a transparent conductive thin film through a spacer so that the transparent conductive thin films face each other. They are arranged opposite to each other. On the other hand, in a capacitive touch panel, a transparent conductive film having a transparent conductive thin film having a predetermined pattern shape is usually formed on the entire surface of the display unit. The pressure-sensitive adhesive optical film of the present invention is applied to either the touch side or the display side.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, all the parts and% in each example are based on weight.

Production Example 1
(Preparation of monomer emulsion (A1))
As a raw material, 380 parts of butyl acrylate, 20 parts of acrylic acid and 0.12 part of 3-methacryloyloxypropyl-trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-503) are added to the container and mixed. A monomer mixture (A1) was obtained. Next, 3.2 parts of a reactive surfactant (anionic) Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd.), 214 parts of ion-exchanged water with respect to 320 parts of the prepared monomer mixture (A1) Was added and stirred at 6000 (rpm) for 5 minutes using a homomixer (made by Tokushu Kika Kogyo Co., Ltd.) to prepare a monomer emulsion (A1).

(Preparation of monomer emulsion (B1))
In a separate container, as raw materials, 15 parts of butyl acrylate, 5 parts of acrylic acid, 80 parts of methyl methacrylate and 3-methacryloyloxypropyl-trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-503) 0.03 Part was added and mixed to obtain a monomer mixture (B1). Next, for 80 parts of the monomer mixture (B1) prepared at the above ratio, 8.8 parts of Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd.) which is a reactive surfactant (anionic), ion exchange 362 parts of water was added, and the mixture was stirred at 6000 (rpm) for 5 minutes using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to prepare a monomer emulsion (B1).

(Preparation of aqueous dispersion containing core-shell emulsion particles)
Into a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer, a dropping funnel and a stirring blade, the monomer emulsion (B1) prepared above was charged, and the reaction vessel was sufficiently purged with nitrogen, and then ammonium persulfate 0.04 Part (0.05% with respect to 80 parts of the monomer mixture (B1)) was added and polymerized at 65 ° C. for 1 hour with stirring to obtain a copolymer that became a core layer. Subsequently, 0.12 part of ammonium persulfate (0.0375% with respect to 320 parts of the monomer mixture (A1)) was further added, and after 10 minutes, the monomer emulsion (A1) was kept with the reaction vessel kept at 65 ° C. Was added dropwise over 3 hours, and then polymerized for 3 hours to form a shell layer to obtain an aqueous dispersion containing core-shell polymer emulsion particles having a solid content of 42%. Next, after cooling the aqueous dispersion containing the polymer emulsion particles to room temperature, a 10% concentration of aqueous ammonia is added to adjust the pH to 8 and the solid concentration is adjusted to 41%. An aqueous dispersion (B1-A1) containing the emulsion particles was obtained.

Production Example 2
(Preparation of monomer emulsion (A2))
Reactive surfactant (anionic) Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd.) 4 parts, ion-exchanged water 268 parts with respect to 400 parts of the monomer mixture (A1) prepared in Production Example 1 Was added and stirred at 6000 (rpm) for 5 minutes using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to prepare a monomer emulsion (A2).

(Preparation of aqueous dispersion (A2) according to (meth) acrylic copolymer emulsion)
Next, in a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, a dropping funnel and a stirring blade, 136 parts of the monomer emulsion (A2) prepared above, with a reactive surfactant (anionic) First, 8 parts of Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd.) and 308 parts of ion-exchanged water were charged, and after the reaction vessel was sufficiently purged with nitrogen, 0.1 part of ammonium persulfate was added and stirred. The polymerization was carried out at 65 ° C. Next, 0.3 part of ammonium persulfate was further added, and after 10 minutes, the remaining monomer emulsion was added dropwise over 3 hours while maintaining the reaction vessel at 65 ° C., and then polymerized for 3 hours to form a solid. A polymer emulsion having a partial concentration of 42% was obtained. Next, after cooling the polymer emulsion to room temperature, aqueous ammonia having a concentration of 10% is added to adjust the pH to 8, and an aqueous dispersion according to a (meth) acrylic copolymer emulsion having a solid content concentration of 41%. (A2) was obtained.

Production Example 3
(Preparation of monomer emulsion (B2))
Add 360 parts of methyl methacrylate, 32 parts of butyl acrylate, 8 parts of acrylic acid and 0.12 part of 3-methacryloyloxypropyl-trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-503) to the container and mix. As a result, a monomer mixture (B2) was obtained. Next, 4 parts of reactive surfactant (anionic) Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd.) and 268 parts of ion-exchanged water are added to 400 parts of the prepared monomer mixture (B2). Using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), the mixture was stirred at 6000 (rpm) for 5 minutes to prepare a monomer emulsion (B2).

(Preparation of aqueous dispersion (B2) according to (meth) acrylic copolymer emulsion)
Next, in a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, a dropping funnel and a stirring blade, 136 parts of the monomer emulsion (B2) prepared above, with a reactive surfactant (anionic) First, 8 parts of Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd.) and 308 parts of ion-exchanged water were charged, and after the reaction vessel was sufficiently purged with nitrogen, 0.1 part of ammonium persulfate was added and stirred. The polymerization was carried out at 65 ° C. Next, 0.3 part of ammonium persulfate was further added, and after 10 minutes, the remaining monomer emulsion was added dropwise over 3 hours while maintaining the reaction vessel at 65 ° C., and then polymerized for 3 hours to form a solid. A polymer emulsion having a partial concentration of 42% was obtained. Next, after cooling the polymer emulsion to room temperature, aqueous ammonia having a concentration of 10% is added to adjust the pH to 8, and an aqueous dispersion according to a (meth) acrylic copolymer emulsion having a solid content concentration of 41%. (B2) was obtained.

Example 1
(Preparation of water-dispersed pressure-sensitive adhesive composition)
With respect to 100 parts of the aqueous dispersion (B1-A1) containing the emulsion particles having the core-shell structure prepared in Production Example 1 with the weight in terms of solid content, the polycarboxylic acid ammonium salt water-soluble resin (Rohm and Haas ( 5 parts of Orotan 165A, 1% aqueous solution having a surface tension of 30.3 [mN / m] was added to prepare a water-dispersed pressure-sensitive adhesive composition.

(Formation of adhesive layer and creation of adhesive member)
The water-dispersed pressure-sensitive adhesive composition was applied onto a polyethylene terephthalate substrate having a thickness of 38 μm by a die coater so that the thickness after drying was 23 μm, and then dried at 100 ° C. for 2 minutes to form a pressure-sensitive adhesive layer. A pressure-sensitive adhesive member was obtained. The polyethylene terephthalate substrate used was subjected to an easy adhesion treatment.

  On the other hand, instead of the polyethylene terephthalate base material, a release film (polyethylene terephthalate base material) having a thickness of 38 μm that has been subjected to a release treatment is used, and a 23 μm thick adhesive is applied to the release treatment surface by the same operation as above. A layer was formed.

Examples 2-8, Comparative Examples 1-4
(Preparation of water-dispersed pressure-sensitive adhesive composition)
In Example 1, water was used in the same manner as in Example 1 except that the type, usage rate, type of water-soluble resin, and usage rate of the (meth) acrylic copolymer emulsion used were changed as shown in Table 1. A dispersion-type pressure-sensitive adhesive composition was obtained.

  In Examples 2 to 4 and Comparative Example 3, for the (meth) acrylic copolymer, an aqueous dispersion (B1-A1) containing core-shell structure emulsion particles was used. In Examples 5 to 6 and Comparative Example 4, the aqueous dispersions (A2) and (B2) according to the (meth) acrylic copolymer emulsion were mixed and used. In Comparative Examples 1 and 2, the aqueous dispersion (A2) according to the (meth) acrylic copolymer emulsion was used alone.

(Formation of adhesive layer and creation of adhesive member)
Using the water-dispersed pressure-sensitive adhesive composition, a pressure-sensitive adhesive member having a pressure-sensitive adhesive layer formed was obtained in the same manner as in Example 1. Further, an adhesive layer was formed on the release film in the same manner as in Example 1.

  Table 1 shows glass transition temperatures (theoretical values based on the FOX formula) of the (meth) acrylic copolymer emulsions obtained in the above examples. The glass transition temperature was calculated using the glass transition temperature (K) of the homopolymer of each monomer described below. Butyl acrylate (228.15K), acrylic acid (379.15K), methyl methacrylate (378.15K). The calculation result of the glass transition temperature is 71.2 ° C. for the (meth) acrylic copolymer (B1) related to the core layer of Production Example 1, and − (meth) acrylic copolymer (A1) related to the shell layer is − 40.2 degreeC, the (meth) acrylic-type copolymer (A2) of manufacture example 2 is -40.2 degreeC, and the (meth) acrylic-type copolymer (B) of manufacture example 3 is 86.3 degreeC.

  The surface tension of the water-soluble resin (C) is adjusted to a 1% aqueous solution using ion-exchanged water, and then an automatic contact angle measuring device (ST-1S type) manufactured by Shimadzu Corporation and a glass tension measurement as a probe thereof. Using a plate, it was determined by the Wilhelmi method at 20 ° C. The measured values are also shown in Table 1.

  The following evaluation was performed about the adhesive layer and adhesive member obtained by the said Example and comparative example. The evaluation results are shown in Table 1.

[Confirm domain size]
Only the pressure-sensitive adhesive layer was taken out from the pressure-sensitive adhesive member and dyed with iodine and ruthenic acid. A sample was prepared by preparing an ultrathin section having a thickness of 80 nm from the dyed adhesive layer with a microtome. The prepared sample was observed with H-7650 manufactured by Hitachi High-Technologies Corporation, which is a transmission electron microscope (TEM). The domain portion was a portion that was heavily dyed with ruthenium, and the (meth) acrylic copolymer emulsion particles were a portion that was dyed relatively thinly. The obtained image was made into a photograph using image processing software, and the length of the maximum part of the domain was measured from the photograph. The results are shown in Table 1.

  The maximum length of the domain is determined by the transmission electron microscope (TEM), and the maximum domain is determined for each photograph taken at three locations, and is the largest of the three domains. The length of the largest part of the domain having the length was taken. Note that an exceptional local maximum domain is excluded from the maximum length domain. Therefore, the TEM image has three or more domains of 1 nm or more and 200 nm or less, and two or less domains are not used.

  In the pressure-sensitive adhesive layer of the example, the ratio of the domain having the maximum portion length of 1 nm to 200 nm was 98% or more with respect to the domain. In Comparative Example 1, only emulsion particles were confirmed.

(Adhesive strength evaluation)
The adhesive members (sheets) prepared in Examples and Comparative Examples were cut into 25 mm width × 150 mm length, and this was pasted by reciprocating a 2 kg roller on the glass plate. Thereafter, it was left in an autoclave at 50 ° C. and 0.5 MPa for 15 minutes, then cooled to 23 ° C., and the adhesive strength when peeled off by a tensile tester at a speed of 300 mm / min in the direction of 180 ° (N / 25 mm ) Was measured.

(Haze evaluation)
The pressure-sensitive adhesive layer having a thickness of 23 μm provided in the release film obtained in each example was subjected to heat treatment at 140 ° C. for 90 minutes. Thereafter, the release film was peeled off, and the sample attached to the glass was used as a sample (initial). The haze value of this initial sample was measured. In addition, this sample was heated in a constant temperature and humidity chamber of 60 ° C. and 90% RH for 500 hours, then the sample was taken out, left at room temperature (23 ° C., 55% RH) for 60 minutes, and then the haze value was obtained. (%) Was measured. The haze value was measured in accordance with JISK-7136 using “HAZEMETER HM-150 type” manufactured by Murakami Color Research Laboratory Co., Ltd. in an atmosphere of 25 ° C. If the haze value of the sample after the heat treatment was less than 2.5, it was “◯”, if it was 2.5 or more and less than 5.0, “Δ”, and if it was 5.0 or more, “x”.

In Table 1, Orotan 165A is a polycarboxylic acid ammonium salt manufactured by Rohm and Haas Co. (surface tension of 1% aqueous solution is 30.3 [mN / m]);
SN Dispersant 5034 is a polycarboxylic acid sodium salt manufactured by San Nopco Corporation (surface tension of 1% aqueous solution is 70.0 [mN / m]);
Aqualic DL-365 is a polyacrylic acid sodium salt manufactured by Nippon Shokubai Co., Ltd. (surface tension of 1% aqueous solution is 73.1 [mN / m]);
Epan 785 indicates a water-soluble resin (1% aqueous solution has a surface tension of 40.4 [mN / m]) manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

Claims (11)

Water containing (meth) acrylic acid alkyl ester as a monomer unit and having a glass transition temperature (where the glass transition temperature is calculated based on the monofunctional monomer in the monomer unit) of −55 ° C. or more and 0 ° C. or less. Dispersed (meth) acrylic copolymer (A),
Water dispersion containing (meth) acrylic acid alkyl ester as a monomer unit and having a glass transition temperature (however, the glass transition temperature is calculated based on a monofunctional monomer in the monomer unit) of 0 ° C. or higher and 180 ° C. or lower. An aqueous dispersion containing a (meth) acrylic copolymer (B) of a mold and a water-soluble resin (C),
At least one of the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) contains a carboxyl group-containing monomer as a monomer unit,
The difference between the glass transition temperature of the (meth) acrylic copolymer (A) and the glass transition temperature of the (meth) acrylic copolymer (B) is 50 ° C. or more, and
The mixing ratio of the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) is (A) / (B) = 50 to 95/5 to 50 (solid content weight ratio). range der of is,
The water-soluble resin (C) is a polycarboxylic acid salt produced separately from the production of the (meth) acrylic copolymer (A) and / or the (meth) acrylic copolymer (B). the optical film for aqueous dispersion-type pressure-sensitive adhesive composition characterized in that it consists of that aqueous dispersion. The ratio of the water-soluble resin (C) is 100 parts by weight in total of the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) in the solid content weight ratio. claim 1 for an optical film water-dispersible pressure-sensitive adhesive composition according to, characterized in that 0.5 to 15 parts by weight. In the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B), one copolymer is a core layer and the other copolymer is in the same emulsion particle. the optical film for water-dispersible pressure-sensitive adhesive composition according to claim 1 or 2, characterized in that it contains emulsion particles having a core-shell structure present as the shell layer. 4. The water-dispersed adhesive for optical films according to claim 3, wherein the core layer is a (meth) acrylic copolymer (B) and the shell layer is a (meth) acrylic copolymer (A). Agent composition. The (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) are an aqueous dispersion of each (meth) acrylic copolymer (A) and a (meth) acrylic copolymer. polymer (B) according to claim 1 or 2 for an optical film water-dispersible adhesive composition according to, characterized in that is derived from an aqueous dispersion of. At least one of the (meth) acrylic copolymer (A) and the (meth) acrylic copolymer (B) is an alkoxysilyl group-containing monomer (provided that the alkoxysilyl group-containing monomer is a monomer unit) The ratio of the alkoxysilyl group-containing monomer is (meth) acrylic copolymer (A) or (meth) acrylic copolymer. polymer optical film for water-dispersible pressure-sensitive adhesive composition according to any one of claims 1 to 5, characterized in that 0.001% by weight of the total monomer units (B). After the application of the optical film for water-dispersible pressure-sensitive adhesive composition according to any one of claims 1 to 6 pressure-sensitive adhesive layer for an optical film, characterized in that one formed by drying. In the pressure-sensitive adhesive layer, the (meth) acrylic copolymer (B) is present as a domain in the resin component formed from the (meth) acrylic copolymer (A), and the domain is a maximum portion. 8. The pressure-sensitive adhesive layer for an optical film according to claim 7 , wherein a ratio of a domain region having a length of 1 nm to 200 nm is 98% or more. The pressure-sensitive adhesive layer, 180 ° peeling method, the temperature 23 ° C., the adhesive strength for a glass plate at a peel rate of 300 mm / min, for an optical film according to claim 7 or 8, wherein the at 5N / 25 mm or more Adhesive layer. A pressure-sensitive adhesive member, wherein the pressure-sensitive adhesive layer for an optical film according to any one of claims 7 to 9 is laminated on at least one side of a support substrate. An image display device comprising at least one pressure-sensitive adhesive layer for an optical film according to any one of claims 7 to 9 or the pressure-sensitive adhesive member according to claim 10 .