TW201700693A - Adhesive composition, adhesive obtained using same, and adhesive for polarizing plates - Google Patents

Abstract

As an adhesive composition having excellent aging characteristics, which is free from the occurrence of bleeding and adverse effect on durability even if the content of an antistatic agent is increased, and which is capable of stably exhibiting antistatic properties over a long period of time, the present invention provides an adhesive composition which contains (A) an acrylic resin and (B) an antistatic agent, and wherein: the acrylic resin (A) contains an amide group and a functional group other than an amide group; a structural unit derived from a monomer (a1) containing a functional group other than an amide group accounts for 1-10% by weight of the acrylic resin (A); the antistatic agent (B) is composed of an ammonium-based antistatic agent; and the content of the antistatic agent (B) is 1.2-15 parts by weight relative to 100 parts by weight of the acrylic resin (A).

Description

Adhesive composition and adhesive using the adhesive composition and adhesive for polarizing plate

The present invention relates to an adhesive composition and an adhesive for using the adhesive composition and an adhesive for a polarizing plate, and more particularly to an antistatic property and durability which can be formed at room temperature and low temperature. An adhesive composition having excellent balance of properties and aging properties and an excellent adhesive, and an adhesive for using the adhesive composition and a polarizing plate.

The liquid crystal display panel is usually obtained by attaching a polarizing plate to a surface of a liquid crystal cell sandwiching a liquid crystal component interposed between two glass plates by interposing an adhesive. In the polarizing plate, a three-layer structure in which a polarizer made of a polyvinyl alcohol-based resin is sandwiched by a protective film made of a triacetyl cellulose resin is used.

In recent years, as a polarizing plate for a liquid crystal display panel, a resin having a high hydrophobicity such as an acrylic resin or a cycloolefin resin has been developed for protecting the double-sided protective film of the polarizing plate (polyvinyl alcohol film). However, the polarizing plate using the hydrophobic resin as the protective film is more easily charged than the polarizing plate using the triacetyl cellulose film in the protective film, and thus is frictionally charged due to friction with the backlight of the liquid crystal display panel. For other reasons, the liquid crystal alignment is disturbed and the display is poor (so-called uneven display, whitening phenomenon), and it becomes a problem.

Here, as a solution to the problem of the above-described triboelectric charging, it has been proposed to add a larger amount of anti-adhesion than the conventional one in the adhesive layer provided on the surface of the polarizing plate for bonding (crimping) to the liquid crystal cell. The electrostatic agent improves the antistatic property (refer to Patent Document 1). [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-79205

[Problems to be Solved by the Invention] However, when the antistatic amount added to the adhesive composition for polarizing plate adhesion of Patent Document 1 is increased, high temperature and high humidity conditions, low temperature conditions, thermal cycle tests, etc. Under severe conditions, the antistatic agent in the above composition may bleed out from the adhesive layer with time, and there is a possibility that the antistatic property is lowered or the durability (weather resistance) such as peeling of the polarizing plate is lowered. Further, as the adhesive for polarizing plate of Patent Document 1 mainly uses a lithium salt-based antistatic agent, it takes time to mature.

Therefore, an adhesive composition which does not bleed out even if a large amount of an antistatic agent is added and which maintains antistatic properties and has excellent ripening characteristics is sought.

The present invention has been made in view of such circumstances, and an object thereof is to provide that even if the content of the antistatic agent is increased, bleeding does not occur, and the durability is not adversely affected, and the antistatic property can be exerted over a long period of time even under various environments, and An adhesive composition having excellent ripening characteristics and an adhesive for using the adhesive composition and an adhesive for a polarizing plate. [Means for solving the problem]

In order to solve the above problems, the inventors of the present invention have conducted intensive studies and found that a specific amount of an ammonium-based antistatic agent is used as the above-mentioned binder composition containing the acrylic resin (A) and the antistatic agent (B). In the antistatic agent (B), two functional groups including a functional group other than a mercapto group and a mercapto group as a whole of the resin component are used as the acrylic resin (A), and a functional group other than the "nonylamine group" is used. The content of the structural unit (that is, the content of the structural unit derived from the monomer (a1) having a functional group other than the amidino group) is set to be more appropriate than the conventional technical knowledge, even if the content of the antistatic agent is increased. Bleed is still not generated, and when used as an adhesive for polarizing plates, antistatic properties and durability can be maintained at a high level and balance, and maturation characteristics can be obtained by using a specific amount of an ammonium salt antistatic agent. It is also an excellent binder composition, or even the completion of the present invention.

That is, the gist of the present invention relates to an adhesive composition comprising an acrylic resin (A) and an antistatic agent (B); characterized in that the acrylic resin (A) contains a non-amine group other than a mercapto group. The functional group, and the structural unit derived from the monomer (a1) having a functional group other than the amide group accounts for 1 to 10% by weight of the acrylic resin (A); and the antistatic agent (B) is composed of the ammonium-based antistatic agent The content of the antistatic agent (B) is 1.2 to 15 parts by weight based on 100 parts by weight of the acrylic resin (A).

Further, the present invention relates to an adhesive comprising a crosslinking agent (C) for crosslinking the above-mentioned adhesive composition, and an adhesive for a polarizing plate which is constituted by the adhesive. [Effects of the Invention]

The adhesive composition of the present invention and the adhesive obtained by crosslinking the adhesive composition have excellent antistatic properties over time, and even more antistatic agents are blended than conventional products. It does not bleed out, and has excellent antistatic properties and durability. In addition, the gel fraction increases in a short period of time, so that the ripening property is also excellent.

Further, the above-described adhesive composition and the adhesive obtained by using the adhesive composition are excellent in durability, light leakage resistance, and rework.

The invention will be described in detail below. Further, in the present invention, a (meth)acrylic group means an acrylic group or a methacrylic group, a (meth) acrylate means an acrylate or a methacrylate, and a (meth) acrylamide means an acryl oxime. Amine or methacrylamide. Further, the acrylic resin refers to a resin obtained by polymerizing a polymerization component containing at least one (meth)acrylate monomer. Further, the single system in the present invention means a compound having a polymerizable unsaturated group, and the functional group of the monomer does not contain the above polymerizable unsaturated group.

The adhesive composition of the present invention contains an acrylic resin (A) and an antistatic agent (B); the acrylic resin (A) contains a functional group other than a guanamine group and a guanamine group; and the antistatic agent (B) is made of ammonium. It is composed of an antistatic agent.

<Acrylic Resin (A)> The acrylic resin (A) constituting the adhesive composition of the present invention contains a functional group other than a mercaptoamine group and a mercapto group, and is derived from a functional group other than a mercapto group. The content of the structural unit of the body (a1) is 1 to 10% by weight based on the entire acrylic resin (A). The content of the structural unit derived from the monomer (a1) having a functional group other than a guanamine group is preferably 1.5 to 8% by weight, more preferably 2 to 5% by weight, particularly preferably 2.5 to 4% by weight. When the content of the structural unit derived from the monomer (a1) having a functional group other than a guanamine group is too large, since the functional group remains in a large amount, the physical property tends to change with time, and the polar component of the adhesive is present. The ratio of the adhesive layer becomes high, and the adhesive layer tends to absorb moisture, so that the durability such as foaming tends to be lowered by heating. When the content of the structural unit derived from the monomer (a1) having a functional group other than the amide group is too small, the acrylic resin cannot sufficiently react with the crosslinking agent in the crosslinking reaction, and it is not sufficient to exhibit an adhesive. Because of the cohesive force, there is a tendency for durability to decrease.

The monomer (a1) having a functional group other than the amidoxime group may be a monomer having a functional group reactive with a crosslinking agent (C) to be described later, and examples thereof include a monomer having a hydroxyl group and a monomer having a carboxyl group. A monomer, a monomer containing an acetoacetyl group, a monomer containing an isocyanate group, a monomer containing a glycidyl group, and the like. Among these, the viewpoint of efficiently crosslinking the reaction is preferable, and it is preferably a monomer having a hydroxyl group or a monomer having a carboxyl group, and a monomer having a hydroxyl group and a monomer having a carboxyl group are preferably used in combination.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 5-hydroxypentyl (meth)acrylate. a hydroxyalkyl acrylate such as hexamethylene acrylate or octahydroxyoctyl (meth)acrylate; a caprolactone modified by a caprolactone-modified (2-hydroxyethyl methacrylate) A monomer; an alkylene-modified monomer such as diethylene glycol (meth)acrylate or polyethylene glycol (meth)acrylate.

Examples of the carboxyl group-containing monomer include (meth)acrylic acid, acrylic acid dimer, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, and itaconic acid. , N-glycolic acid, cinnamic acid, and the like. Among them, (meth)acrylic acid is preferably used from the viewpoint of copolymerizability or durability.

As the monomer containing the ethyl oxime group, for example, 2-(ethionethoxy)ethyl (meth)acrylate or allyl acetate can be used.

As the monomer containing an isocyanate group, for example, isocyanate-2-propenyloxyethyl ester, isocyanic acid-2-methylpropenyloxyethyl ester, or such an alkylene oxide adduct can be used. .

As the above-mentioned monomer containing a glycidyl group, for example, glycidyl (meth)acrylate or allyl g-propyl (meth)acrylate can be used.

In addition, the monomer (a1) having a functional group other than the amidoxime group may be used singly or in combination of two or more kinds.

In the present invention, the acrylic resin (A) preferably has a carboxyl group as a functional group other than the guanamine group, and the other than the above-described guanamine group, in view of the fact that the gel fraction is increased in a short period of time and the aging property is improved. The functional group monomer (a1) preferably contains from 1 to 5% by weight of the structural unit derived from the carboxyl group-containing monomer. The content of the structural unit derived from the monomer having a carboxyl group is preferably from 1.5 to 4% by weight, more preferably from 2 to 3.5% by weight. When the content of the structural unit derived from the monomer having a carboxyl group in the acrylic resin (A) is too small, the catalytic effect of the carboxyl group in the crosslinking reaction is not easily obtained, so that a functional group reactive with a crosslinking agent, particularly a hydroxyl group, may be The reaction of the isocyanate-based crosslinking agent does not proceed sufficiently, and the ripening tends to take time. When the content is too large, since the reactive functional group remains, it is observed that the physical properties tend to change with time, and the adhesive composition is observed. Since the ratio of the medium-polar component becomes high, it has been observed that the adhesive layer tends to absorb moisture, and the durability such as foaming due to heating tends to decrease.

Further, the acrylic resin (A) of the present invention contains a guanamine group, and the structural unit derived from the amide group-containing monomer (a2) preferably contains 1 to 25% by weight, more preferably 2 to 10% by weight, and more preferably 3 ~7% by weight is particularly good. When the content of the structural unit derived from the amidino group-containing monomer (a2) is too large, the ratio of the polar component of the acrylic resin becomes high, and the adhesive layer formed by crosslinking is easily absorbed with water, so that it is durable. When the degree of the decrease is small, there is a tendency that the cohesive force as the adhesive agent is not exhibited and the durability after heating and humidification is lowered.

The monomer (a2) containing the guanamine group may, for example, be a (meth) acrylate containing a guanamine group. Examples of the above-mentioned (meth) acrylate containing a guanamine group include methoxymethyl (meth) acrylamide, ethoxymethyl (meth) acrylamide, and propoxymethyl ( Methyl) acrylamide, isopropoxymethyl (meth) acrylamide, n-butoxymethyl (meth) acrylamide, isobutoxymethyl (meth) acrylamide, etc. Alkoxyalkyl (meth) acrylamide monomer; dialkyl (meth) acrylamide such as dimethyl (meth) acrylamide or diethyl (meth) acrylamide Monomer; (meth) acrylamide, N-methylol (meth) acrylamide, (meth) propylene oxime Porphyrin and the like. Among them, from the viewpoint of compatibility and durability with the antistatic agent (B) described later, it is preferably a dialkyl (meth) acrylamide monomer, which is preferably dimethyl (meth) acrylamide. .

Further, the amidoxime group-containing monomer (a2) may be used alone or in combination of two or more.

The acrylic resin (A) of the present invention preferably further contains a structural unit derived from the alkyl (meth)acrylate monomer (a3), and may also contain other ethylenically unsaturated monomers copolymerizable from other copolymers as needed. (a4) (The following may be described as a structural unit of "other copolymerizable monomer (a4)").

The structural unit derived from the alkyl (meth) acrylate monomer (a3) is a main structural unit of the acrylic resin (A), and the content is preferably 50 to 99% by weight, more preferably 60 to 98% by weight. It is more preferably 70 to 95% by weight, and particularly preferably 70 to 93% by weight. When the content of the structural unit derived from the alkyl (meth) acrylate monomer (a3) is too large, a structural unit derived from the monomer (a2) containing a guanamine group and a functional group derived from a amide containing group may be derived. The content of the structural unit of the monomer (a1) is reduced, and it is difficult to obtain the effect of the present invention. When the amount is too small, the acrylic resin tends to be difficult to polymerize or the productivity tends to be lowered.

As the alkyl (meth)acrylate monomer (a3), for example, the number of carbon atoms of the alkyl group is usually from 1 to 20, preferably from 1 to 18, more preferably from 1 to 12, and from 1 to 8 Particularly preferred are, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and tertiary (meth)acrylate. Butyl ester, n-propyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isodecyl (meth)acrylate And lauryl (meth)acrylate, hexadecyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isodecyl (meth)acrylate, and the like. Among them, from the viewpoint of versatility and adhesive properties, n-butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are preferable. These may be used alone or in combination of two or more.

The content of the structural unit derived from the other copolymerizable monomer (a4) is preferably from 0 to 50% by weight, more preferably from 3 to 20% by weight, even more preferably from 5 to 20% by weight, even more preferably from 6 to 15% by weight. % is particularly good. When the content of the other copolymerizable monomer (a4) is too large, the glass transition temperature tends to be high, and the workability tends to be lowered. When the content is too small, the effect of adjusting the refractive index tends to be difficult to be exhibited.

Examples of the other copolymerizable monomer (a4) include benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenoxydiethylene glycol (meth)acrylate. Monocyclic aromatic monomer such as o-phenylphenoxyethyl methacrylate; cyclohexyl oxyalkyl (meth) acrylate, tert-butylcyclohexyloxyethyl (meth) acrylate, (methyl) An alicyclic monomer such as dicyclopentanyl acrylate; acrylonitrile, methacrylonitrile, vinyl acetate, vinyl stearate, vinyl chloride, vinylidene chloride, vinyl toluene, vinyl pyrrolidone, methyl ethyl ketone, two Methyl allyl vinyl ketone and the like. These may be used alone or in combination of two or more.

Among these, in view of the adjustment of the refractive index and the ease of adjustment of birefringence, it is preferred to use a monomer containing an aromatic ring, and use benzyl (meth)acrylate or phenoxyethyl (meth)acrylate. Phenoxydiethylene glycol (meth)acrylate is more preferred. Moreover, it is preferable to use an alicyclic-containing monomer from the viewpoint of easy adjustment of the refractive index and adjustment of birefringence and excellent adhesion to the low-polarity adherend (cycloolefin).

In the case where the other copolymerizable monomer (a4) is a monomer containing an aromatic ring and a monomer containing an alicyclic ring, the content of the structural unit derived from the other copolymerizable monomer (a4) is preferably 0 to 10 The weight % is preferably 0 to 5% by weight. When the content is too large, there is a tendency that the long-term storage stability of the adhesive composition is lowered or the compatibility is lowered.

In addition, the content ratio of the structural unit derived from each of the monomers (a1) to (a4) in the acrylic resin (A) can be measured, for example, in the following manner. In other words, the adhesive layer is picked up from the polarizing plate with the adhesive layer obtained by the method described later, and the ¹ H-NMR is performed by the following <measurement conditions> using the NMR apparatus described later. Measurement (CDCl ₃ , 300K) and ¹³ C-NMR measurement (CDCl ₃ , MAS, 300K), the structural unit derived from the monomers (a1) to (a4) of the acrylic resin in the adhesive layer can be calculated. The proportion of the content.

<Measurement Equipment> NMR (Bruker Biospin AVANCE-600 ( ¹ H), Varian, UNITY-INOVA-400 ( ¹³ C))

<Measurement conditions> Observation frequency: 600MHz ( ¹ H); 100MHz ( ¹³ C) Measurement solvent: CDCl ₃ (add a small amount of pyridine-d5 when measuring ¹³ C) Measurement temperature: 300K ( ¹ H); 300K ( ¹³ C) Chemical shift Standard: Measurement solvent ( ¹ H: 7.25 ppm; ¹³ C: 77.05 ppm) Sample speed: 20 Hz ( ¹ H); 2,000 Hz ( ¹³ C)

The acrylic resin (A) used in the present invention may contain a monomer (a1) having a functional group other than a guanamine group and a monomer (a2) containing a guanamine group, which are appropriately selected. The copolymerization component of the alkyl acrylate monomer (a3) and the other copolymerizable monomer (a4) is produced by polymerization. The above polymerization can be carried out by a conventional method such as solution radical polymerization, suspension polymerization, bulk polymerization, or emulsion polymerization.

In other words, the acrylic resin (A) may be obtained by, for example, mixing or dropping a copolymerization component containing a monomer selected as described above and a polymerization initiator in an organic solvent, and polymerizing under predetermined polymerization conditions. Among these polymerization methods, solution radical polymerization and bulk polymerization are preferably used, and radical polymerization using a solution is more preferable.

Examples of the organic solvent used in the polymerization reaction include aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane; esters such as ethyl acetate and butyl acetate; n-propanol and isopropanol. Aliphatic alcohols; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Among these solvents, ethyl acetate, acetone, methyl ethyl ketone, butyl acetate, and ethyl acetate, acetone, methyl ethyl ketone, and butyl acetate are preferable in view of easiness of polymerization reaction, effect of chain transfer, and ease of drying and adhesion at the time of application of the adhesive. Toluene and methyl isobutyl ketone, among which ethyl acetate, acetone, and methyl ethyl ketone are suitably used.

Moreover, as a polymerization initiator used for the radical polymerization of the solution, for example, a general radical polymerization initiator: 2,2'-azobisisobutyronitrile, 2,2'-azobis- Azo-based initiators such as 2-methylbutyronitrile, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(methylpropionic acid); benzoic acid peroxide An organic peroxide such as hydrazine, oxidized laurel, bis(tributyl) peroxide or cumene hydroperoxide may be appropriately selected and used in combination with the monomer to be used. These solvents may be used singly or in combination of two or more.

In the present invention, the weight average molecular weight of the acrylic resin (A) is preferably from 600,000 to 2.5 million, more preferably from 1,000,000 to 1.8 million, and even more preferably from 1.2 million to 1.55 million, and is preferably from 1.4 to 1.5 million. When the weight average molecular weight is too small, the durability tends to be lowered. When the weight average molecular weight is too large, the solvent is required to be diluted in a large amount at the time of production, so that the drying property tends to be lowered.

Further, the weight average molecular weight is a weight average molecular weight obtained by converting the molecular weight of the standard polystyrene, and is used in a high performance liquid chromatography apparatus ("Waters 2695 (main body)" and "Waters 2414" manufactured by Waters Corporation, Japan. ")") 3 columns in series: Shodex GPC KF-806L (excluding the limit molecular weight: 2 × 10 ⁷ , separation range: 100 ~ 2 × 10 ⁷ , theoretical number of plates: 10,000 plates / support, filler material: styrene - Divinylbenzene copolymer, filler particle size: 10 μm).

In the present invention, the acrylic resin (A) may be composed of a single acrylic resin, or two or more acrylic resins may be blended. In view of the viewpoint of broadly adjusting the physical properties, or the fineness of the gel fraction obtained by blending, and considering the durability, it is preferable to mix two or more kinds of acrylic resins, especially considering production. Sex, etc., should be mixed with two kinds of acrylic resin.

When the acrylic resin (A) is an acrylic resin composition obtained by blending two kinds of acrylic resins, the structural unit derived from the amidino group-containing monomer (a2) may be contained in the two kinds of acrylic acid to be blended. The resin may be contained only in any of the acrylic resins, and is preferably contained in an acrylic resin containing no structural unit derived from the monomer (a1) having a functional group other than a mercapto group.

Further, the structural unit derived from the monomer (a1) having a functional group other than a guanamine group may be contained in the two kinds of acrylic resins to be blended, or may be contained only in any of the acrylic resins. It is more preferably contained in the acrylic resin containing only one of the structural units derived from the monomer (a2) containing the guanamine group.

In other words, when the acrylic resin (A) is in particular an acrylic resin composition containing two kinds of acrylic resins, the combination of the two kinds of acrylic resins to be blended may be: a combination of a structural unit of a guanamine group monomer (a2) and an acrylic resin (Aab) derived from a structural unit derived from a monomer (a1) having a functional group other than a guanamine group; The structural unit of the amino group monomer (a2) does not contain an acrylic resin (Aa) derived from a structural unit of the monomer (a1) having a functional group other than a guanamine group, and contains a source derived from a guanamine-containing group. a functional unit of the monomer (a1) and a combination of an acrylic resin (Ab) derived from a structural unit of the amidino group-containing monomer (a2), and may also contain a source derived from a decylamine The above-mentioned acrylic resin (Aa) or acrylic acid is combined with an acrylic resin (Aab) of a structural unit of the monomer (a2) and a structural unit derived from a monomer (a1) having a functional group other than a guanamine group. Any of the resins (Ab).

In the present invention, an acrylic resin containing a structural unit derived from a monomer (a2) containing a mercapto group and containing no monomer (a1) derived from a functional group other than a mercapto group is blended in the present invention. (Aa), an acrylic resin (Ab) containing a structural unit derived from a monomer (a1) having a functional group other than a guanamine group, and containing no structural unit derived from a monomer (a2) containing a guanamine group In terms of adhesion characteristics or durability, the viewpoint is preferable.

It is presumed that due to the interaction between the acrylic resin (Aa) and (Ab), a pseudo-crosslinked structure is formed between the two acrylic resins, whereby the obtained adhesive exhibits an appropriate cohesive force and excellent Stress relaxation. It is considered that when an acrylic resin containing a carboxyl group is used as an acrylic resin (Ab) having a functional group other than a guanamine group, an electron interaction between an electron donor group, that is, a sulfhydryl group and an electron withdrawing group, that is, a carboxyl group, is considered. When the acrylic resin (Aa) and (Ab) have a physical pseudo bond force and the internal cohesive force is changed to be high, an adhesive layer having excellent stress relaxation properties and excellent durability is formed.

The content of the amidino group-containing monomer (a2) in the acrylic resin (Aa) is preferably from 1 to 25% by weight, more preferably from 2 to 15% by weight, based on the total of the polymerization component of the acrylic resin (Aa). It is more preferably 3 to 10% by weight, and particularly preferably 4 to 7% by weight. When the ratio of the entire polymerization component is too small, the adhesive does not exhibit sufficient cohesive force, and the tendency to deteriorate after heating and humidification is observed. On the other hand, when the ratio of the polar component of the adhesive is high, the adhesive layer is likely to absorb moisture, so that foaming or the like is observed in the heating test, and durability is similar. The tendency to decrease.

The blending amount of the monomer (a1) having a functional group other than the amide group in the acrylic resin (Ab) is preferably from 1 to 20% by weight, based on the total amount of the polymerization component of the acrylic resin (Ab), and is 1.5 to 1.5%. More preferably, 15% by weight, more preferably 2 to 12% by weight, and particularly preferably 2.5 to 8% by weight. When the ratio of the polymer component is too small, the functional group tends to remain in a large amount, so that the physical properties tend to change with time, and since the ratio of the polar component of the binder becomes high, the adhesive layer easily absorbs moisture. Therefore, there is a tendency that the durability such as foaming due to heating tends to decrease. When the ratio of the total amount of the polymerization component is too large, the acrylic resin and the crosslinking agent in the crosslinking reaction are not sufficiently reacted to exhibit sufficient cohesive force with respect to the binder, and thus the durability tends to be lowered. The monomer (a1) which is a functional group other than a mercapto group in the acrylic resin (Ab) is preferably a monomer having a hydroxyl group, a monomer having a carboxyl group, and a monomer having a hydroxyl group and a monomer having a carboxyl group. And use the best.

The ratio of the blending when the two kinds of acrylic resins are blended is, for example, an acrylic resin (Aa) having a structural unit derived from a monomer (a2) containing a mercapto group, and having a mercapto group derived therefrom. When the combination of the acrylic resin (Ab) of the structural unit of the monomer (a1) other than the functional group is (Ab): (Aa) = 100: 40 to 100: 500 (weight ratio), (Ab) : (Aa) = 100: 60 ~ 100: 400 (weight ratio) is better, (Ab): (Aa) = 100: 80 ~ 100: 350 (weight ratio) is even better. When the ratio of the acrylic resin (Aa) to the acrylic resin (Ab) is too large, the degree of crosslinking of the adhesive decreases, and the cohesive force tends to decrease. When the amount is too small, the degree of crosslinking of the adhesive increases, and the stress increases. The tendency to reduce slack.

When two or more kinds of acrylic resins are blended, the weight average molecular weight of each of the acrylic resins is preferably from 1,000,000 to 2,000,000, and is preferably from 1.3 to 1.6 million. When the weight average molecular weight is too small, the durability tends to be lowered, and if the weight average molecular weight is too large, the compatibility tends to be lowered and the adhesive properties tend to be uneven.

When two or more kinds of the above acrylic resins are blended, the degree of dispersion (weight average molecular weight/number average molecular weight) of the two or more kinds of the acrylic resin (A) to be blended is preferably 30 or less, more preferably 15 or less, and is 7 or more. The following is even better, especially below 5. If the degree of dispersion is too high, the cohesive force tends to decrease. Further, the lower limit of the above dispersion is usually 2.

<Antistatic agent (B)> Next, the antistatic agent (B) used for the adhesive composition of the present invention will be described. The antistatic agent (B) used in the adhesive composition of the present invention is an ammonium-based antistatic agent, and specifically, a cationic antistatic agent of a quaternary ammonium salt such as an alkylammonium sulfonate. Examples of the alkylammonium salt include methyltri-n-butylammonium bis(trifluoromethanesulfonyl) quinone imine [melting point 27.5 ° C (manufacturer published value) (manufactured by 3M Company, product name: FC-4400) )], tetrabutylammonium bis(trifluoromethanesulfonyl) quinone imine [melting point 92 ° C (manufacturer published value) (manufactured by MERCK)], tetrabutylammonium bromide [melting point 119 ° C (manufacturer announced) Value) (made by Wako Pure Chemical Industries, Ltd.), tetraamylammonium bromide [melting point 98 ° C (manufacturer published value) (manufactured by Wako Pure Chemical Industries, Ltd.)], tetraoctyl ammonium bromide [melting point 99 ° C (manufacture) (published value) (made by Wako Pure Chemical Industries, Ltd.), ethyl dimethyl propyl ammonium bis(trifluoromethanesulfonyl) quinone imine [melting point -11 ° C (manufacturer published value) (manufactured by MERCK) ], n-butyltrimethylammonium bis(trifluoromethanesulfonyl) quinone imine [melting point 19 ° C (published according to ionic liquid II CMC ISBN 978-4-7813-0878-4)], methyl trioctyl ammonium Bis(trifluoromethanesulfonyl) quinone imine [melting point -75 ° C (published according to ionic liquid II CMC ISBN 978-4-7813-0878-4)], methyl tributyl ammonium sulfate methyl ester [solid (Ardrich ,], tetraethylammonium trifluoromethanesulfonate, tetrabutylammonium benzoate, tetrabutylsulfate Methyl ester, tetrabutylammonium nonafluorobutanesulfonate, tetra-n-butylammonium hexafluorophosphate, tetrabutyl ammonium trifluoroacetate, tetra hexyl ammonium tetrafluoroborate, tetra hexyl ammonium. These may be used alone or in combination of two or more.

The above antistatic agent (B) is preferably a solid at normal temperature (25 ° C), and from the viewpoint of solubility, the melting point is preferably 25 to 120 ° C, preferably 25 to 100 ° C, more preferably 25 to 50 ° C. When the melting point is too low, the durability tends to be extremely lowered at the time of bleeding. When the melting point is too high, the antistatic agent becomes agglomerated during dissolution, and it tends to take a long time until it dissolves. In addition, the melting point at the time of mixing two or more types of the antistatic agent (B) is a melting point calculated from the average melting point calculated from the respective melting points and blending ratios (distribution ratios) of the mixed antistatic agents.

Therefore, in the above examples, the antistatic agent (B) is preferably used in view of the melting point: methyl tri-n-butylammonium bis(trifluoromethanesulfonyl) quinone imine (manufactured by 3M Company), tetrabutylammonium Bis(trifluoromethanesulfonyl) quinone imine (manufactured by MERCK Co., Ltd.), tetrabutylammonium bromide (manufactured by Wako Pure Chemical Industries, Ltd.), tetraamyl ammonium bromide (manufactured by Wako Pure Chemical Industries, Ltd.), bromination Tetraoctyl ammonium (manufactured by Wako Pure Chemical Industries, Ltd.), methyl tributylammonium sulfate (manufactured by Ardrich Co., Ltd.), methyl tri-n-butylammonium bis(trifluoromethanesulfonyl) quinone imine (3M) Company system) is particularly good.

Further, from the viewpoint of antistatic property, it is preferred that the anion component of the above antistatic agent (B) is an antistatic agent of (trifluoromethanesulfonyl) quinone imine anion, wherein methyl tri-n-butylammonium double is used. (Trifluoromethanesulfonyl) quinone imine (made by 3M Company) is particularly preferred.

In addition, the cationic component of the ammonium-based antistatic agent (B) of the present invention is preferably an alkylammonium cation, and has a carbon number of 1 in the viewpoint of excellent compatibility with the acrylic resin (A). The alkylammonium cation of the alkyl group of ~6 is particularly preferred. When the carbon number of the alkyl chain is too large, the melting point and the electrical conductivity tend to decrease.

The content of the antistatic agent (B) is preferably 1.2 to 15 parts by weight, more preferably 2.5 to 14 parts by weight, even more preferably 5 to 13 parts by weight, based on 100 parts by weight of the acrylic resin (A). 9~12 parts by weight is especially good. When the content of the antistatic agent (B) is too small, there is a tendency that sufficient antistatic performance or antistatic property stability with time is not obtained, and if too much, the antistatic agent (B) is partially crystallized. The bleed out is a bright spot of the liquid crystal display panel, and the appearance is poor, and the durability tends to be remarkably lowered.

Further, in the present invention, the antistatic agent (B) is composed of an ammonium antistatic agent, but an antistatic agent other than the ammonium antistatic agent may be used in combination. Other antistatic agents are generally used, and examples thereof include an imidazole salt, an aliphatic sulfonate, a higher alcohol sulfate salt, a higher alcohol alkylene oxide adduct sulfate salt, a higher alcohol phosphate salt, and an advanced one. An anionic antistatic agent such as an alcohol alkylene oxide adduct phosphate salt; a potassium bis(fluorosulfonyl) sulfonium iodide, a lithium bis(trifluorosulfonyl) ruthenium iodide or a base such as lithium chloride Metal salts; alkaline earth metal salts, higher alcohol alkylene oxide adducts, polyalkylene glycol fatty acid esters, and the like. In addition, when the other antistatic agent is used in combination, it may be used in a range that does not interfere with the effect of the above-mentioned ammonium antistatic agent. Specifically, the amount of other antistatic agent is usually 5 in the entire antistatic agent. It is used in the range of % by weight or less.

The adhesive composition of the present invention contains the specific acrylic resin (A) and the antistatic agent (B) as essential components, and the binder composition is crosslinked by the crosslinking agent (C). The adhesive of the present invention.

As the crosslinking agent (C), for example, an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, a melamine crosslinking agent, an aldehyde crosslinking agent, and an amine crosslinking can be used. Agent, metal chelate crosslinking agent, and the like.

Examples of the isocyanate crosslinking agent include toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, toluene diisocyanate, and diisocyanate-1,3. - phenyl dimethyl ester, diisocyanate - 1,4- phenyl dimethyl ester, hexamethylene diisocyanate, 4,4-diisocyanate diphenylmethane, diisocyanate isophor Ketoester, 1,3-bis(isocyanatomethyl)cyclohexane, tetramethylphenyl diisocyanate, naphthyl 1,5-diisocyanate, triphenyl triisocyanate a methane ester, an adduct of the polyisocyanate compound and a polyhydric alcohol compound such as trimethylolpropane, a biuret or a isocyanurate of the polyisocyanate compound. Among them, the viewpoint of a long pot life or an excellent compatibility with a resin is particularly preferable as an addition product of toluene 2,4-diisocyanate and trimethylolpropane.

Examples of the epoxy-based crosslinking agent include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and glycerol diepoxypropyl acrylate. Ether, glycerol triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, Pentaerythritol polyepoxypropyl erythritol, diglyceryl polyglycidyl ether, 1,3-bis(N,N'-diepoxypropylaminemethyl)cyclohexane, N,N, N'N'-tetraepoxypropyl-m-xylylenediamine. Among them, in view of high reactivity, it is 1,3-bis(N,N'-diepoxypropylaminemethyl)cyclohexane, N,N,N'N'-tetraepoxypropyl-m-phenylene Dimethyldiamine is particularly good.

Examples of the aziridine-based crosslinking agent include tetramethylolethane propionate-tri-β-aziridine propionate, trimethylolpropane propionate-tri-β-aziridine ester, and N. N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide) Wait.

Examples of the melamine-based crosslinking agent include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxymethyl melamine, and hexaethoxyoxymethyl melamine. , hexahexyloxymethyl melamine, melamine resin, and the like.

Examples of the aldehyde crosslinking agent include glyoxal, malondialdehyde, succinaldehyde, maleic aldehyde, glutaraldehyde, formaldehyde, acetaldehyde, and benzaldehyde.

Examples of the amine-based crosslinking agent include hexamethylenediamine, triethylenediamine, polyethylenimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, and isophor. Ketodiamine, amine based resin, polydecylamine, and the like.

Examples of the metal chelate-based crosslinking agent include ethyl mercaptoacetone or a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, ruthenium, magnesium, vanadium, chromium, or zirconium. An acetoacetyl ester coordination compound, and the like.

Among these, from the viewpoint of excellent durability and light leakage resistance, an isocyanate crosslinking agent and an epoxy crosslinking agent are preferable, and an isocyanate crosslinking agent and an epoxy crosslinking agent are particularly preferable. Further, in the present invention, from the viewpoint of improving the ripeness due to the catalytic effect of the ammonium-based antistatic agent, an isocyanate-based crosslinking agent is also preferable.

In addition, these crosslinking agents (C) may be used alone or in combination of two or more.

The content of the crosslinking agent (C) is preferably 0.001 to 10 parts by weight, more preferably 0.1 to 8 parts by weight, even more preferably 0.3 to 7 parts by weight, per 100 parts by weight of the acrylic resin (A). 0.5 to 6 parts by weight is particularly good. When the amount of the crosslinking agent (C) is too small, the durability tends to be lowered. When the amount is too large, the stress relaxation property is lowered or the ripening property tends to be lowered.

Further, the adhesive composition of the present invention preferably further contains a decane coupling agent (D). By blending the decane coupling agent (D), the adhesion to the optical member can be improved when the adhesive is formed.

Examples of the decane coupling agent (D) include a cyclodecane coupling agent containing an epoxy group, a decane coupling agent containing a (meth) acrylonitrile group, a decane coupling agent containing a mercapto group, and a decane containing a hydroxyl group. A coupling agent, a decane coupling agent containing a carboxyl group, a decane coupling agent containing an amine group, a decane coupling agent containing a guanamine group, a decane coupling agent containing an isocyanate group, and the like. These may be used alone or in combination of two or more.

Among these, it is preferred to use an epoxy group-containing decane coupling agent, a mercapto group-containing decane coupling agent, and an epoxy group-containing decane coupling agent and a mercapto group-containing decane coupling agent to improve wet heat durability. The idea that the adhesion does not rise excessively is also ideal. Further, the oligomer-type decane compound which is partially hydrolyzed and polycondensed is also preferable from the viewpoint of excellent durability and reworkability.

Specific examples of the epoxy group-containing decane coupling agent include γ-glycidoxypropyltrimethoxydecane, γ-glycidoxypropyltriethoxydecane, and γ-. Glycidoxypropylmethyldiethoxydecane, γ-glycidoxypropylmethyldimethoxydecane, methyltris(epoxypropyl)decane, β-(3,4 ring Oxycyclohexyl)ethyltrimethoxydecane, β-(3,4 epoxycyclohexyl)ethyltrimethoxydecane, etc., as preferred, γ-glycidoxypropyltrimethoxy Decane, γ-glycidoxypropyltriethoxydecane, γ-glycidoxypropylmethyldiethoxydecane, β-(3,4 epoxycyclohexyl)ethyltrimethoxy Decane and so on.

Specific examples of the mercapto group-containing decane coupling agent include γ-mercaptopropyltrimethoxydecane, γ-mercaptopropyltriethoxydecane, and γ-mercaptopropyldimethoxymethylnonane. An oxime ketone alkoxy oligomer (fluorenyl-modified ethyl decanoate/methyl decanoate low condensate) containing SH group.

The content of the decane coupling agent (D) is usually 0.001 to 10 parts by weight, preferably 0.01 to 1 part by weight, based on 100 parts by weight of the acrylic resin (A), more preferably 0.03 to 0.8 part by weight. 0.05 to 0.5 parts by weight is particularly preferred. When the content of the decane coupling agent (D) is too small, the adhesion to the optical member tends to be unfavorable, and if it is too large, the bleeding tends to be observed and the durability tends to be lowered. Further, there is a tendency that the adhesion of the adhesive is excessively increased and the workability is lowered.

Further, the adhesive composition of the present invention may be blended in a range which does not impair the effects of the present invention: other adhesives, urethane resin, rosin, rosin ester, hydrogenated rosin ester, phenol resin, An adhesive such as an aliphatic petroleum resin, an alicyclic petroleum resin or a styrene resin; various additives such as a coloring agent, a filler, an antioxidant, an ultraviolet absorber, and a functional dye; or by irradiation with ultraviolet rays or radiation A compound that develops color or causes discoloration. Further, in addition to the above additives, impurities and the like contained in the raw material for production of the constituent components of the binder composition may be contained in a small amount. These blending amounts can be appropriately set to obtain desired physical properties.

In the present invention, an adhesive layer layer formed by crosslinking the above-described adhesive composition of the present invention is formed on an optical member (optical laminate), whereby an optical layer provided with an adhesive layer can be obtained. member.

The optical member provided with the adhesive layer is preferably provided with a release sheet on a surface opposite to the surface of the optical member of the adhesive layer.

The method for producing the optical member provided with the adhesive layer is as follows: [1] applying the adhesive composition to the optical member, drying the bonded release sheet, and performing the method at room temperature (23 ° C) or a method of aging treatment under heating, [2] applying the adhesive composition to a polarizing plate and drying, and then performing the aging treatment at room temperature or under heating to bond the release sheet The method [3] applies the adhesive composition to the release sheet, and after drying, the polarizing plate is attached and subjected to a ripening treatment at room temperature or under heating, [4] comprising an adhesive. The object is applied onto a release sheet and dried, and a method of laminating a polarizing plate after aging treatment at room temperature or in a heated state is carried out. Among them, the method of the above [2] is preferable from the viewpoint of not damaging the substrate and the adhesion to the substrate.

The above-mentioned ripening treatment is carried out in order to obtain a balance of the adhesive properties in terms of the reaction time of the chemical crosslinking of the adhesive. As a condition of ripening, the temperature is usually from room temperature to 70 ° C, and the time is usually from 1 day to 30 days. Specifically, for example, it can be carried out under conditions of 23 ° C, 1 day to 20 days, 23 ° C, 3 days to 10 days, 40 ° C, 1 day to 7 days, and the like.

In the above-mentioned ripening treatment, in order to obtain a balance of the adhesive properties, for example, when the adhesive composition is crosslinked by using an isocyanate crosslinking agent, the ripening is particularly preferable at 23 ° C for about 7 days.

Further, since the adhesive composition of the present invention is excellent in aging characteristics, crosslinking is carried out in a short period of time, and the gel fraction is increased and stabilized, so that an adhesive having excellent adhesive properties can be obtained even if the aging treatment time is short. . Therefore, the ripening treatment time can be shortened more than in the past, and it is very advantageous in terms of productivity. Further, since the adhesive property is stabilized in a short period of time, it is also possible to prevent, for example, when the film having the adhesive layer is stored in a roll shape, the particles of the anti-adhesion layer of the protective film are transferred to the adhesive, that is, the so-called adhesive The problem of "orange peel".

When applying the above-mentioned adhesive composition, it is preferable to dilute the adhesive composition in a solvent and apply it as a dilution concentration, preferably 5 to 60% by weight based on the concentration of the residual component of the heating, and 10 to 30% by weight. good. Further, the solvent is not particularly limited as long as it dissolves the binder composition, and for example, an ester solvent such as methyl acetate, ethyl acetate, methyl acetate or ethyl acetate; acetone; A ketone solvent such as methyl ethyl ketone or methyl isobutyl ketone; an aromatic solvent such as toluene or xylene; or an alcohol solvent such as methanol, ethanol or propanol. Among these, it is suitable to use in view of solubility, drying property, price, etc.: an ester solvent, especially ethyl acetate; a ketone solvent, especially methyl ethyl ketone.

Further, the application of the above-mentioned adhesive composition is carried out by a conventional method such as roll coating, die coating, gravure coating, smear coating, or screen printing.

Regarding the gel fraction of the adhesive layer produced by the above method, the gel fraction of the adhesive layer after one day of application and drying of the adhesive composition solution is defined as "initial gel fraction". Rate Gi", the gel fraction of the sample which was re-cooked for 6 days at room temperature (23 ° C) was defined as "the gel fraction Ga after ripening", and was heated in an oven at 80 ° C after the above 6 days of ripening. When the gel fraction of the adhesive layer for 24 hours is defined as "the gel fraction Gh after heating", the gel fraction Ga of the adhesive layer is considered to be 40 to 85 in view of durability and light leakage resistance. %, 45~75% is better, 50~70% is better. When the gel fraction Ga is too low, the cohesive force of the adhesive layer becomes weak, and the bubble tends to be generated in a high-temperature environment. If the gel content is too high, the adhesive layer becomes hard, and the adhesive layer is hardened in a high-temperature and high-humidity environment. The adhesiveness is lowered and the tendency to peel off is likely to occur. The gel fraction can be adjusted, for example, by adjusting the amount or type of the crosslinking agent; adjusting the blending ratio of the acrylic resin (A) of the binder composition component, or the monomer composition and molecular weight of the acrylic resin (A). Wait and adjust.

Moreover, the rate of change of the gel fraction Ga of the adhesive layer produced by the above method relative to the initial gel fraction Gi (Ga/Gi) is usually less than 300%, preferably less than 150%. . When the rate of change (Ga/Gi) of the gel fraction Ga after the above-mentioned aging is too high, the maturing time of the physical properties of the adhesive layer reaching stability is prolonged, and the productivity tends to be lowered.

Further, the rate of change (Gh/Ga) of the gel fraction Gh after heating of the adhesive layer relative to the gel fraction Ga after the ripening is usually 90 to 110%, preferably 95 to 105%. When the rate of change (Gh/Ga) of the gel fraction Gh after heating is too low or too high, there is a tendency that the physical properties of the adhesive agent vary depending on the environment of the storage place, and durability and the like tend to be lowered.

Further, the gel fraction ratio is an indication of the degree of crosslinking (degree of hardening) of the composition, which is calculated, for example, by the following method. That is, the adhesive layer is scraped from the adhesive sheet formed of the adhesive member layer formed on the optical member (for example, a polarizing plate) as a substrate, and the adhesive layer is made of SUS metal mesh of 200 mesh. The coating was further immersed in ethyl acetate under the conditions of 23 ° C × 24 hours, and the weight percentage of the insoluble binder component (crosslinking component) remaining in the metal mesh was determined as the gel fraction. The initial gel fraction Gi, the gel fraction Ga after ripening, and the gel fraction Gh after heating also include the ripening conditions, measurement methods, and the like, which will be described in detail later.

The above initial adhesion is calculated in the following manner. The polarizing plate provided with the adhesive layer was cut into a width of 25 mm in width, the release sheet was peeled off, and the adhesive layer side was pressed to an alkali-free glass plate ("EAGLE XG" manufactured by CORNING Co., Ltd.) The polarizing plate is attached to the glass plate. Thereafter, autoclave treatment (50° C., 0.5 MPa, 20 minutes) was carried out, and after standing at 23° C. and 50% RH for 24 hours, a 180° peel test was performed.

Further, the thickness of the adhesive layer in the optical member provided with the adhesive layer is preferably 5 to 300 μm, more preferably 10 to 50 μm, still more preferably 10 to 30 μm. When the thickness of the adhesive layer is too small, the adhesive property tends to be difficult to be stabilized. When the thickness is too thick, there is a tendency that appearance defects such as bubbles are increased during production.

The optical member in the present invention is not particularly limited, and examples thereof include an optical film which is applied to an image display device such as a liquid crystal display device, an organic EL display device, or a PDP, for example, a polarizing plate, a phase difference plate, an elliptically polarizing plate, and optical compensation. A film, a brightness enhancement film, or the like, or the like. Among them, the present invention is effective in the case of a polarizing plate, and is particularly effective in the case of a polarizing plate which is required to withstand high shrinkage such as shrinkage of a polarizing plate.

Therefore, by using the adhesive of the present invention, the polarizing plate is attached to the liquid crystal display panel of the liquid crystal cell (glass plate), and the antistatic property of the surface remains for a long time even if it is continuously used under severe conditions such as high temperature and high humidity. Without failing, it is possible to produce a liquid crystal display panel which is excellent in durability without causing peeling of the polarizing plate or the like.

In addition, the polarizing plate used in the present invention is usually formed by laminating a protective film on both sides of a polarizing film, and a single protective film polarizing plate or the like having a protective film on the side where the polarizing plate is bonded is removed for thinning. Examples of the protective film include a highly hydrophobic resin film such as an acrylic film, a polyethylene film, a polypropylene film, or a cycloolefin film. Further, in the present invention, a conventional use of a triethylenesulfonated cellulose film can also be used as a protective film.

As the polarizing film, a film made of a polyvinyl alcohol-based resin having an average degree of polymerization of 1,500 to 10,000 and a degree of saponification of 85 to 100 mol% is used as a raw film, and an aqueous solution of iodine-potassium iodide or a dichroic dye is used. The uniaxially stretched film obtained by dyeing (usually about 2 to 10 times, preferably about 3 to 7 times the stretching ratio).

The polyvinyl alcohol-based resin is usually produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate, but may contain a small amount of an unsaturated carboxylic acid (including a salt, an ester, a guanamine, a nitrile, etc.), A component which can be copolymerized with vinyl acetate, such as an olefin, a vinyl ether or an unsaturated sulfonate. Further, it is also possible to use a polyvinyl alcohol in the presence of an acid to react with an aldehyde, for example, a polyvinyl butyral resin, a polyvinyl formal resin, or the like, a so-called polyethylene acetal resin and polyvinyl alcohol. derivative.

For the antistatic property of the polarizing plate provided with the adhesive layer manufactured by the above method, after the polarizing plate provided with the adhesive layer is manufactured, it is allowed to stand under 23 ° C × 50% RH ambient gas for 24 hours. After that, the separator of the adhesive layer is removed, and the surface resistance value of the adhesive layer measured by the surface resistivity measuring device described later is preferably less than 1.0×10 ¹² Ω. /□, less than 1.0 × 10 ¹¹ Ω / □ is better, less than 5.0 × 10 ⁹ Ω / □ and even better. When the initial surface resistance value Ri is too high, the polarizing plate is charged by friction with the backlight of the liquid crystal display panel or the like, and display defects tend to occur.

Moreover, in terms of the stability over time of the antistatic property of the polarizing plate provided with the adhesive layer, after manufacturing the polarizing plate provided with the adhesive layer, the oven is heated at a temperature of 40 ° C and a humidity of 90% RH. After storing for 100 hours, and then standing at 23 ° C × 50% RH ambient gas for 24 hours, the separator of the adhesive layer was removed, and the surface resistivity of the adhesive layer was measured using a surface resistivity measuring device described later. When the obtained value is defined as "surface resistance value Rt after humidification", the rate of change with time in the "surface resistance value Rt after humidification" / "initial surface resistance value Ri" = rate of change with time ( Rt/Ri) should be maintained in the range of 0.6 to 1.4, more preferably in the range of 0.8 to 1.2, and even better in the range of 0.9 to 1.1. If the antistatic property changes with time (variation of the rate of change with time) is too large, depending on the product, deviations may occur, and the use in a long time, high temperature and high humidity environment, and the backlight of the liquid crystal display panel When the polarizing plate is charged, the tendency to display defects is observed. Moreover, when used as a touch panel or the like, the sensitivity of the sensor changes, and there is a tendency that it is not normally driven. [Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by the following examples as long as it does not exceed the gist of the invention. In addition, "part" and "%" in the example mean the weight basis.

First, various acrylic resins were produced as follows. Further, the measurement of the weight average molecular weight of the acrylic resin and the gel fraction of the adhesive was carried out in accordance with the above method.

[Preparation of Acrylic Resin (A)] In the production of the following resin, (a1) to (a4) appended to the substance name indicate the type of the monomer, and each of them indicates that (a1) is other than the amidino group. The monomer of the functional group, (a2) is a monomer containing a guanamine group, (a3) is an alkyl (meth) acrylate monomer, and (a4) is another copolymerizable monomer.

<Production of Acrylic Resin (A-1)> 82.5 parts of butyl acrylate [BA] (a3), 10 parts of benzyl acrylate [BzA] (a4), and 2-hydroxyethyl acrylate [HEA] (a1) 0.5 parts, 7 parts of [AAc](a1) acrylic acid, 47.2 parts of ethyl acetate as a solvent, 42 parts of acetone, and 0.013 parts of azobisisobutyronitrile [AIBN] as a polymerization initiator were provided with reflux cooling. In a 4-neck round bottom flask equipped with a stirrer, a nitrogen gas inlet, and a thermometer, an AIBN and an ethyl acetate were added to react at a reflux temperature for 3.25 hours, and then diluted with ethyl acetate to obtain an acrylic resin (A-1). A solution having a weight average molecular weight of 1.5 million and a dispersion of 3.3.

<Production of Acrylic Resin (A-2)> 88.5 parts of butyl acrylate (a3), 10 parts of benzyl acrylate (a4), 0.5 part of 2-hydroxyethyl acrylate (a1), and 1 part of acrylic acid (a1) 47.2 parts of ethyl acetate as a solvent, 42 parts of acetone, and 0.013 parts of azobisisobutyronitrile [AIBN] as a polymerization initiator were supplied with a reflux cooler, a stirrer, a nitrogen gas inlet, and a thermometer. In the round bottom flask, AIBN and ethyl acetate were added to react at reflux temperature for 3.25 hours, and then diluted with ethyl acetate to obtain an acrylic resin (A-2) (weight average molecular weight: 1.5 million, degree of dispersion: 3.4). Solution.

<Production of Acrylic Resin (A-3)> 93 parts of butyl acrylate (a3), 2 parts of methyl methacrylate [MMA] (a3), and 5 parts of dimethyl acrylamide [DMAA] (a2) 43 parts of ethyl acetate as a solvent, 42 parts of acetone, and 0.011 parts of azobisisobutyronitrile [AIBN] as a polymerization initiator were supplied with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer. In the round-bottomed round flask, the AFBN and ethyl acetate were added and reacted at reflux temperature for 3.25 hours, and then diluted with ethyl acetate to obtain an acrylic resin (A-3) (weight average molecular weight: 1.4 million, degree of dispersion: 4.6). Solution.

<Production of Acrylic Resin (A-4)> 78 parts of butyl acrylate (a3), 2 parts of methyl methacrylate (a3), 20 parts of dimethyl acrylamide (a2), and acetic acid B as a solvent 43 parts of ester, 42 parts of acetone, and 0.011 part of azobisisobutyronitrile [AIBN] as a polymerization initiator were fed into a 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer. A solution of the acrylic resin (A-4) (weight average molecular weight: 1.4 million, dispersion degree: 3.6) was obtained by diluting with ethyl acetate by appropriately adding AIBN and ethyl acetate at a reflux temperature for 3.25 hours.

<Production of Acrylic Resin (A-5)> 89.8 parts of butyl acrylate (a3), 5 parts of dimethyl acrylamide (a2), 0.2 parts of 2-hydroxyethyl acrylate (a1), acrylic acid (a1) 5 parts, 43 parts of ethyl acetate as a solvent, 42 parts of acetone, and 0.011 part of azobisisobutyronitrile [AIBN] as a polymerization initiator were provided with a reflux condenser, a stirrer, a nitrogen gas inlet, and In a four-necked round bottom flask, a mixture of AIBN and ethyl acetate was added at a reflux temperature for 3.25 hours, and then diluted with ethyl acetate to obtain an acrylic resin (A-5) (weight average molecular weight: 1.5 million, dispersion degree) 3.5) solution.

The content of the raw material monomer component, the weight average molecular weight (Mw), and the degree of dispersion of the acrylic resins (A-1) to (A-5) obtained as described above are shown in Table 1 below.

[Table 1] Blending of acrylic resin (A)

<Antistatic agent (B)> Further, as an antistatic agent (B), the following compounds were prepared. (B-1): Methyl tri-n-butylammonium bis(trifluoromethanesulfonyl) quinone imine melting point 27.5 ° C (manufacturer published value) (manufactured by 3M Company, "FC-4400") (B-2) : tetrabutylammonium bis(trifluoromethanesulfonyl) quinone imine melting point 92 ° C (manufacturer published value) (manufactured by MERCK) (B-3): methyl tributyl ammonium sulfate methyl ester solid (Ardrich (B-4): 1-butyl-2,3-dimethyltrifluoromethanesulfonate imidazole melting point 100 ° C (manufacturer published value) (manufactured by MERCK) (B-5): tetrabutyl bromide Base melting point 100 ° C (manufacturer's published value) (manufactured by Wako Pure Chemical Industries, Ltd.) (B-6): lithium bistrifluoromethanesulfonimide (tetraethylene glycol dimethyl ether dispersion) (manufactured by Sanko Chemical Co., Ltd.) , "SANKONORU TGR")

<Crosslinking agent (C)> Then, as the crosslinking agent (C), the following compounds were prepared. (C-1): a 55% ethyl acetate solution of a toluene diisocyanate adduct of trimethylolpropane (manufactured by Nippon Polyurethane Co., Ltd., "CORONATE L-55E") (C-2): 1,3 -Bis(N,N'-diepoxypropylaminomethyl)cyclohexane ("TETRAD-C", manufactured by Mitsubishi Gas Chemical Co., Ltd.)

<Hydrane coupling agent (D)> Further, as a decane coupling agent (D), the following compounds were prepared. (D-1): epoxy-based decane coupling agent [3-glycidoxypropyltrimethoxydecane ("KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.)]

[Examples 1 to 10, Comparative Examples 1 to 7] [Preparation of Adhesive Composition (Solution)] Each of the blended components prepared and prepared as described above was blended at a ratio shown in Table 2 below. The adhesive composition was prepared and diluted with ethyl acetate to prepare a binder composition solution (solid content concentration: 13%). In the following Table 2, the respective amounts of the antistatic agent (B), the crosslinking agent (C), and the decane coupling agent (D) are converted into 100 parts by weight based on the total amount of the acrylic resin (A). The value obtained.

【Table 2】

Then, the adhesive composition solutions of the examples and the comparative examples were applied to a polyester release sheet so that the thickness after drying became 25 μm, and after drying at 100 ° C for 3 minutes, the formed adhesive was composed. The layer was transferred to a polarizing plate (protective film: TAC film manufactured by Fujifilm Co., Ltd.), and aged for 7 days under conditions of 23 ° C × 65% RH to obtain a polarizing plate provided with an adhesive layer for testing.

Using the polarizing plate provided with the above-mentioned adhesive layer, the antistatic property [initial and surface resistance after humidification and its rate of change] and the ripening characteristics [initial and after ripening] were measured and evaluated according to the methods described below. , gel fraction after heating and its rate of change], and durability [heat resistance and heat and humidity resistance]. These results are combined and shown in Table 3 below. Further, the test piece of the polarizing plate provided with the adhesive layer was cut and used so as to be 0 degree (parallel) with respect to the extending axis of the polarizing plate.

[Evaluation of initial antistatic property] After the test piece of the above polarizing plate provided with the adhesive layer was allowed to stand under an ambient gas of 23 ° C × 50% RH for 24 hours, the separator of the adhesive layer was peeled off and used. The surface resistivity measuring device (manufactured by Mitsubishi Chemical Corporation ANALYTECH, the device name "Hiresta-UP MCP-HT450") measures the surface resistance value of the adhesive layer. This measurement is taken as the initial surface resistance value. The evaluation criteria are as follows. (Evaluation Criteria) ◎: Less than 5.0 × 10 ⁹ Ω / □ ○: 5.0 × 10 ⁹ Ω / □ or more and less than 1.0 × 10 ¹¹ Ω / □ △: 1.0 × 10 ¹¹ Ω / □ or more and less than 1.0 × 10 ¹² Ω/□ ×: 1.0×10 ¹² Ω/□ or more

[Evaluation of antistatic property after humidification] In order to observe changes in antistatic property with time, the test piece of the above polarizing plate provided with the adhesive layer was stored in an oven at a temperature of 40 ° C and a relative humidity of 90% for 100 hours. Thereafter, after standing for 24 hours under an ambient gas of 23 ° C × 50% RH, the separator of the adhesive layer was peeled off and the surface resistance value of the adhesive layer was measured. It is set as the surface resistance value after duration (heating). The rate of change is the initial surface resistance value and the surface resistance value after heating, and the rate of change is calculated using the following formula. The evaluation criteria are as follows. Rate of change (change with time) = [surface resistance value after heating] / [initial surface resistance value] (evaluation basis) ◎: The rate of change is 0.9 or more and less than 1.1 ○: The rate of change is 0.8 or more and less than 0.9, or 1.1 The above does not reach 1.2 △: the rate of change is less than 0.6 or less than 0.8, or 1.2 or less is less than 1.4 ×: the rate of change is less than 0.6, or 1.4 or more

[Evaluation of ripening characteristics] The resin solution was applied to a polyester-based release sheet to have a thickness of 25 μm after drying, and dried at 100 ° C for 3 minutes, and then the formed adhesive composition layer was transferred. A polarizing plate (protective film: TAC film manufactured by Fujifilm Co., Ltd.) was used as a sample for measuring "initial gel fraction" for one day under conditions of 23 ° C × 65% RH, and matured for 7 days (added in the above 1 day) For the first 6 days, the sample for the measurement of the gel fraction after the ripening was placed in the oven at 80 ° C for 24 hours, and the sample was measured as the "gel fraction after heating".

The measurement of the gel fraction was also calculated by the following method as described previously. That is, the adhesive sheet is scraped from the adhesive sheet (the separator is not provided) in which the adhesive layer is formed on the polarizing plate as the substrate, and the adhesive layer is made of 200 mesh SUS. The metal mesh was coated and immersed in ethyl acetate at 23 ° C for 24 hours, and the weight percentage of the insoluble binder component remaining in the metal mesh was defined as "gel fraction".

From the "initial gel fraction" obtained by the above method and the "gel fraction after ripening", the rate of change of the gel fraction after ripening was calculated by the following formula. The evaluation criteria are as follows. Rate of change of gel fraction after ripening (%) = [gel fraction after ripening] / [initial gel fraction] × 100 (basis of evaluation of rate of change of gel fraction after ripening) ○: rate of change not Up to 150% △: The rate of change is 150% or more, less than 300% ×: The rate of change is more than 300%

Moreover, the rate of change of the gel fraction after heating was calculated from the "gel fraction after ripening" and "gel fraction after heating" by the above method. The evaluation criteria are as follows. Rate of change of gel fraction after heating (%) = [gel fraction after heating] / [gel fraction after ripening] × 100 (Evaluation criteria for rate of change of gel fraction after heating) ○: Rate of change 95% or more is less than 105% △: 90% or more is less than 95%, or 105% or more is less than 110% ×: the rate of change is less than 90%, or 110% or more

[Evaluation of Durability] The release sheet of the obtained polarizing plate sample provided with the adhesive layer was peeled off, and the adhesive layer side was pressed against an alkali-free glass plate (EAGLE XG, manufactured by CORNING Co., Ltd.). After the polarizing plate and the glass plate were bonded together, high temperature and high pressure treatment (50 ° C, 0.5 MPa, 20 minutes) was carried out, and thereafter, evaluation of foaming and peeling in the following endurance test (heat resistance test, moisture heat resistance test) was carried out visually. Further, the size of the test piece used in the test was 20 cm × 15 cm (stamping).

[Durability] (1) Heat resistance test The durability test at 80 ° C for 240 hours was carried out as follows. (2) Moisture resistance test The durability test at 60 ° C × 90% RH × 240 hours and the endurance test at 85 ° C × 85% RH × 240 hours were evaluated as follows. (Evaluation Criteria) Whether or not the tests (1) and (2) have disadvantages (foaming, streaking, floating, peeling) were evaluated by optical microscopy and visual observation. The evaluation criteria are as follows. (Evaluation Criteria) ◎: No defects were observed in optical microscope observation. ○: In the optical microscope observation, a defect was observed at an edge portion within 0.5 mm from the end portion of the polarizing plate. △: A defect of about 1 mm which was visually confirmed was observed at a portion within 0.5 mm from the end portion of the polarizer. ×: A defect visually confirmed or a peel of 1 mm or more was observed at a side (close to the center) 0.5 mm from the end portion of the polarizing plate.

The results of these tests and the evaluations are shown in Table 3 below.

[Table 3] Test results (evaluation)

According to the evaluation results of the above Table 3, the adhesives of Examples 1 to 10 which are composed of the adhesive composition of the present invention have a good balance of antistatic property, durability, and ripening characteristics, and are excellent in comparison thereto. The structural unit of the monomer (a1) having a functional group other than a guanamine group is less than 1% by weight of the acrylic resin (A). The adhesives of Comparative Examples 2 and 3 have significantly poor aging characteristics and durability. good. It is also known that the acrylic resin (A) does not contain the binder of Comparative Example 4 derived from the structural unit of the amidino group-containing monomer (a2), and cannot satisfy the stability of antistatic property with time, and durability. Also not good.

Further, it was found that the adhesives of Comparative Examples 5 to 7 using an antistatic agent other than the ammonium antistatic agent as the antistatic agent (B) could not satisfy the stability of the antistatic property with time, or the ripening property and durability. At least one of them. Further, it was found that the adhesive of Comparative Example 1 in which the amount of the antistatic agent (B) was less than the limited range could not satisfy the initial antistatic property.

Further, according to the evaluation results described in the above Table 3, it was found that even in Examples 2, 3, and 9, 10 in which the antistatic agent (B) having a relatively large amount of blending was not observed, there was no adhesion test from the adhesive layer. The defects caused by the exudation of the antistatic agent occur, and the adhesive of the present invention improves the stability of the antistatic property with time, and the durability and the ripening property are even when the antistatic agent is blended in a relatively large amount. Balanced and excellent.

Further, the polarizing plate provided with the adhesive layer obtained by using the adhesive compositions of the above Examples 1 to 3, 8 to 10 and Comparative Example 1 was used for antistatic properties under low temperature conditions [surface resistance value, Electrostatic discharge (ESD GUN) unevenness disappearing time] Measurement and evaluation were carried out in accordance with each method shown below. The test is shown in Table 4 below.

[Evaluation of Antistatic Property under Low Temperature Conditions] The polarizing plate provided with the adhesive layer prepared in each of the above Examples and Comparative Examples was allowed to stand under a 4 ° C × 55% RH ambient gas for 24 hours, and then bonded. The separator of the agent layer was peeled off and the surface resistivity of the adhesive layer was measured under a 4 ° C × 55% RH ambient gas using a surface resistivity measuring device (manufactured by Mitsubishi Chemical Corporation, apparatus name "Hiresta-UP MCP-HT450"). The evaluation criteria for the values are as follows. (Evaluation Criteria) ◎: Less than 5.0 × 10 ⁹ Ω / □ ○: 5.0 × 10 ⁹ Ω / □ or more and less than 1.0 × 10 ¹¹ Ω / □ △: 1.0 × 10 ¹¹ Ω / □ or more and less than 1.0 × 10 ¹² Ω/□ ×: 1.0×10 ¹² Ω/□ or more

[Liquid crystal display unevenness test (electrostatic discharge (ESD GUN) uneven disappearance time)] After the polarizing plate provided with the adhesive layer prepared in each of the above examples and comparative examples was cut into 100 mm × 100 mm, The release sheet was peeled off and attached to a liquid crystal panel (manufactured by INNOLAX Co., Ltd.). Further, a polarizing plate provided with an adhesive layer prepared separately is attached to a crossed nicol state on the opposite side, and the transmitted light is blocked. Then, the liquid crystal panel to which the polarizing plate of the adhesive layer was attached was placed on the backlight, and the surface of the polarizing plate prepared in the example was subjected to an electrostatic tester (ESSB3011 (electrostatic tester) manufactured by NOISE Research Co., Ltd. ) and GT-30R (discharge gun) make it contact with discharge +15kV static electricity. At this time, the time (seconds) from the occurrence of the static unevenness (whitening phenomenon) caused by the generation to the original state was measured and evaluated. The shorter the time, the better the electrical characteristics. When static electricity is generated on the surface of the polarizing plate, whitening occurs due to uneven static electricity, and the liquid crystal may exhibit poor display. The measurement was carried out at 23 ° C, 55% RH ambient gas and 4 ° C, 55% RH ambient gas. (Evaluation criteria) ◎: The static electricity unevenness disappeared after less than 1 second. ○: Static electricity unevenness disappeared after 1 second or more and less than 5 seconds. △: Static electricity unevenness disappeared after 5 seconds or more and less than 20 seconds. ×: Static electricity unevenness disappeared for 20 seconds or more.

【Table 4】

According to the evaluation results described in the above Table 4, the adhesives of Examples 1 to 3 and 8 to 10 which are composed of the adhesive composition of the present invention have excellent surface resistance values even under low temperature conditions, and are excellent. Antistatic properties. It is also known that, for Examples 1 to 3 and 8 to 10, although the surface resistance values of the polarizing plates are equal to the evaluation results under low temperature conditions, no mixing amount of the antistatic agent (B) is observed. Difference, but in the display unevenness test of the liquid crystal panel closer to the practical state, the examples 2, 3, and 9, 10 in which a large amount of the antistatic agent (B) is blended exhibit a short disappearance time of unevenness, and are more excellent. The antistatic property was further known in Examples 3 and 10 to have the same degree of display unevenness as the room temperature conditions (the conditions for the evaluation of the initial antistatic property described above). Therefore, it is known that the adhesive of the present invention is balanced and excellent even when a relatively large amount of the antistatic agent is blended in order to improve the stability of the antistatic property with time, and further, even in a low temperature condition. It also has excellent antistatic properties.

The above embodiments are shown in the specific embodiments of the present invention, but the above embodiments are merely illustrative and not limiting. Various changes apparent to those skilled in the art are intended to be included within the scope of the present invention. [Industrial use]

The adhesive composition of the present invention and the adhesive agent formed by crosslinking the adhesive composition do not bleed out even if the content of the antistatic agent is increased, and the adhesive durability is not adversely affected. The optical member having the adhesive layer obtained by using the adhesive for the optical member is excellent in antistatic property and excellent in aging characteristics, and is particularly protected by coating with a highly hydrophobic resin. Adhesives for adhesion of the surface of the polarizing plate of the film are very effective.

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Claims (10)

An adhesive composition comprising an acrylic resin (A) and an antistatic agent (B), wherein the acrylic resin (A) contains a functional group other than a guanamine group and a guanamine group, and is derived from The structural unit of the monomer (a1) having a functional group other than a guanamine group accounts for 1 to 10% by weight of the acrylic resin (A); the antistatic agent (B) is composed of an ammonium-based antistatic agent, and the antistatic agent The content of the agent (B) is 1.2 to 15 parts by weight based on 100 parts by weight of the acrylic resin (A). The adhesive composition according to claim 1, wherein the acrylic resin (A) has a carboxyl group as a functional group other than the guanamine group. The adhesive composition according to claim 1 or 2, wherein the structural unit derived from the monomer having a carboxyl group accounts for 1 to 5% by weight of the acrylic resin (A). The adhesive composition according to claim 1 or 2, wherein the acrylic resin (A) has a structural unit derived from a monomer (a2) containing a mercapto group, and is derived from a mercapto group-containing The structural unit of the monomer (a2) accounts for 1 to 25% by weight of the acrylic resin (A). The adhesive composition according to claim 1 or 2, wherein the acrylic resin (A) is an acrylic resin composition containing two or more kinds of acrylic resins. The adhesive composition of claim 5, wherein the two or more acrylic resins have a weight average molecular weight of 1,000,000 to 2,000,000, respectively. The adhesive composition according to claim 1 or 2, wherein the acrylic resin (A) is an acrylic resin composition containing a structural unit derived from a monomer (a2) containing a mercapto group. The acrylic resin (Aa) containing no structural unit derived from the monomer (a1) having a functional group other than a guanamine group, and the structure containing the monomer (a1) derived from a functional group other than the guanamine group The unit is not contained in the acrylic resin (Ab) derived from the structural unit of the amidino group-containing monomer (a2). An adhesive composition according to claim 1 or 2, which contains a crosslinking agent (C). An adhesive agent obtained by crosslinking a binder composition according to any one of claims 1 to 8 with a crosslinking agent (C). An adhesive for a polarizing plate is obtained by using an adhesive as disclosed in claim 9 of the patent application.