KR101019751B1 - Adhesive composition and optical member - Google Patents

Abstract

An object of this invention is to provide the acrylic adhesive composition excellent in rework property and heat resistance, and the optical member provided with this. As a means for solving such a problem, (a1) acrylic acid ester or methacrylic acid ester, a primary hydroxyl group-containing monomer having a primary hydroxyl group in the (a2) molecule, and a secondary hydroxyl group having a secondary hydroxyl group in the (a3) molecule The copolymer polymer (A2) which increased the crosslinking degree of the polymer (A1) by adding a crosslinking agent to the copolymer polymer (A1) which copolymerized the hydroxyl group containing monomer or the tertiary hydroxyl group containing monomer which has a tertiary hydroxyl group, It is characterized by the above-mentioned. A pressure-sensitive adhesive composition is adopted.

(Meth) acrylic acid ester, crosslinking agent, copolymer polymer, adhesive composition

Description

Adhesive composition and optical member {ADHESIVE COMPOSITION AND OPTICAL MEMBER}

The present invention relates to an adhesive composition and an optical member.

Generally, so-called flat display panels, such as a liquid crystal display panel and a plasma display panel, are laminated | stacked various optical films, such as a polarizing plate, a retardation plate, and an antireflection film, by an adhesion layer.

For example, acrylic resin is used for the adhesion layer used for a polarizing plate in order to ensure the outstanding adhesiveness, optical transparency, etc. Acrylic resin is resin which is excellent in transparency which has acrylic acid ester or methacrylic acid ester as a main component, but contains primary hydroxyl groups, such as 4-hydroxybutyl acrylate, in order to make it reworkable when used as an adhesion layer. It may contain the monomer to make.

At this time, rework property means the property which is hard to peel off with respect to a to-be-adhered body, and which can be peeled off easily when trying to peel off. Conventionally, development of the adhesion layer which consists of acrylic resin containing a hydroxyl-containing monomer is advanced here.

[Patent Document 1] International Publication WO 2004/099334 pamphlet.

By the way, an adhesive layer may require heat resistance and heat-and-moisture heat resistance with rework property. In order to improve the heat resistance and heat-and-moisture resistance of an adhesion layer, it is effective to crosslink the acrylic resin which comprises an adhesion layer. On the other hand, when crosslinking advances, the hydroxyl group concentration in an adhesion layer may fall and rework property may fall. Therefore, in order to simultaneously provide rework resistance, heat resistance, and moist heat resistance to the adhesive layer, it is necessary to precisely control the gel fraction depending on the crosslinking degree and the degree of crosslinking.

In order to crosslink the acrylic resin containing the monomer containing a hydroxyl group, the isocyanate type crosslinking agent is used suitably. However, since an isocyanate type crosslinking agent is easy to react with the residual moisture in an adhesive composition, there existed a problem that the isocyanate type crosslinking agent which concerns on a crosslinking reaction is relatively small, and it is difficult to control crosslinking degree precisely. For this reason, it is necessary to use another kind of crosslinking agent instead of the isocyanate type crosslinking agent which is sensitive to moisture. However, when using another crosslinking agent, it is necessary to add the other monomer which has a corresponding functional group, and for this reason, it was necessary to make the compounding ratio of a primary hydroxyl group containing monomer relatively small. However, if the compounding ratio of the primary hydroxyl group-containing monomer is relatively small, it is natural but the reworkability cannot be sufficiently secured. Thus, in the conventional adhesive composition, it was difficult to improve rework resistance, heat resistance, and moisture heat resistance simultaneously.

This invention is made | formed in view of the said situation, and an object of this invention is to provide the acrylic adhesive composition excellent in rework resistance, heat resistance, and moisture heat resistance, and the optical member provided with this.

In order to achieve the above object, the present invention adopts the following configuration.

The adhesive composition of this invention is an acrylic acid ester and / or methacrylic acid ester, the primary hydroxyl group containing monomer which has a primary hydroxyl group in a molecule | numerator, the secondary hydroxyl group containing monomer which has a secondary hydroxyl group in a molecule | numerator, and / or 3 It is characterized in that the copolymer is made by copolymerizing a tertiary hydroxyl group-containing monomer having a hydroxyl group of a class, which is crosslinked by a crosslinking agent (a4).

Moreover, in the adhesive composition of this invention, the mass ratio [(secondary hydroxyl group containing monomer and / or tertiary hydroxyl group containing monomer) / of a primary hydroxyl group containing monomer, a secondary hydroxyl group containing monomer, and / or a tertiary hydroxyl group containing monomer is / (Primary hydroxyl group-containing monomer)] is preferably 2 or more.

Moreover, in the adhesive composition of this invention, it is preferable that the said copolymer polymer contains the acrylic acid ester and / or methacrylic acid ester which have a functional group in any one of a carboxyl group, an epoxy group, and an amine group.

Next, the optical member of the present invention is characterized in that the pressure-sensitive adhesive composition described above is applied to one or both surfaces of the optical sheet.

ADVANTAGE OF THE INVENTION According to this invention, the acrylic adhesive composition excellent in rework property, heat resistance, and moisture heat resistance, and the optical member provided with this can be provided.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

`` Adhesive composition ''

The pressure-sensitive adhesive composition of this embodiment is composed of acrylic ester and / or methacrylic acid ester (a1 component), primary hydroxyl group-containing monomer (a2 component) having a primary hydroxyl group in a molecule, and a secondary hydroxyl group in a molecule. A copolymer (A1) is formed by copolymerizing a tertiary hydroxyl group-containing monomer and / or a tertiary hydroxyl group-containing monomer (a3 component) having a tertiary hydroxyl group, and a crosslinking agent is added thereto to increase the degree of crosslinking of the copolymer produced by the crosslinking agent. The copolymerized polymer (A2) is contained.

a1 component becomes a main component of the adhesive composition of this embodiment, and provides transparency and adhesiveness to an adhesive composition.

In addition, a2 component is a monomer containing a primary hydroxyl group, and the primary hydroxyl group contained in this monomer is easy to crosslinking reaction with a crosslinking agent. Therefore, the crosslinking degree of an adhesive composition can be improved by adding a2 component, and heat resistance and heat and moisture resistance can be improved.

On the other hand, although a3 component is a monomer which has a hydroxyl group similarly to a2 component, the hydroxyl group of this a3 component is a secondary or tertiary hydroxyl group, and it is hard to react with a crosslinking agent. Therefore, by adding a3 component, the hydroxyl group derived from a3 component remains in an adhesive composition, and by this, rework property can be ensured. Thus, according to the adhesive composition of this embodiment, heat resistance, moist heat resistance, and rework resistance can be improved simultaneously.

Moreover, when a hydroxyl group remains in an adhesive composition, a stress relaxation property will become high. Thereby, when the adhesive composition of this embodiment is applied to the adhesion layer of a polarizing plate, for example, light leakage of a polarizing plate can be prevented.

Moreover, the crosslinking degree of an adhesive composition is added to the copolymer polymer which comprises the adhesive composition of this embodiment by adding the acrylic ester and / or methacrylic acid ester which have a functional group of any one of a carboxyl group, an epoxy group, and an amine group (a4 component). It is possible to further increase the heat resistance, it is also possible to further improve the heat resistance and moisture heat resistance.

Hereinafter, the a1 to a4 components, the crosslinking agent, and other additive components will be described.

(a1 ingredient)

It is preferable that the acrylic acid ester and / or methacrylic acid ester which is an a1 component do not have a functional group which becomes a crosslinking point, and also the acrylate and / or methacrylate which are about 1-14 carbon atoms of an esterified substituent {hereinafter "( Methacrylate "is preferred from the viewpoint of excellent transparency and good adhesion characteristics.

The range of 80 mass%-98.9 mass% is preferable, and, as for the compounding ratio of the a1 component in a copolymer polymer (A1), the range of 88 mass%-97.5 mass% is more preferable.

As a specific example of the acrylic acid ester and / or methacrylic acid ester which is a1 component,

Methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate,

t-butyl (meth) acrylate, isobutyl (meth) acrylate,

Hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,

n-octyl (meth) acrylate, isooctyl (meth) acrylate,

n-nonyl (meth) acrylate, isononyl (meth) acrylate,

n-decyl (meth) acrylate, isodecyl (meth) acrylate,

n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate,

n-tetradecyl (meth) acrylate, methoxyethyl (meth) acrylate,

Ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate,

Cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate,

Phenoxyethyl (meth) acrylate,

Nonylphenoxypolyethylene glycol (meth) acrylate, benzyl (meth) acrylate,

Isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and the like. Especially as a1 component of the adhesive composition for optical members, containing n-butyl acrylate as a main component is preferable at the point which can exhibit high adhesiveness.

(a2 component)

The primary hydroxyl group containing monomer which is a2 component has a primary hydroxyl group used as a crosslinking point at the time of crosslinking reaction with a crosslinking agent in a molecule | numerator. As a specific example of a primary hydroxyl group containing monomer,

2-hydroxyethyl (meth) acrylate,

4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate,

8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate,

12-hydroxylauryl (meth) acrylate,

(4-hydroxymethylcyclohexyl) methyl acrylate,

N-methylol (meth) acrylamide, N-2-hydroxyethyl (meth) acrylamide,

Vinyl alcohol, aryl alcohol, 2-hydroxyethyl vinyl ether,

4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, etc. are mentioned. In particular, as a primary hydroxyl-containing monomer, a (meth) acrylate compound is preferable.

The range of 0.1 mass%-5 mass% is preferable, and, as for the compounding ratio of the a2 component in a copolymer polymer (A1), the range of 0.5 mass%-2 mass% is more preferable. When a2 component is less than 0.1 mass%, since the number of hydroxyl groups used as a crosslinking point is insufficient, the crosslinking degree of a copolymer polymer falls, and since heat resistance of an adhesive composition falls by this, it is unpreferable. Moreover, when a2 component exceeds 5 mass%, since the crosslinking degree increases, the flexibility of a copolymer polymer falls, and rework property and adhesiveness fall, it is unpreferable.

(a3 ingredient)

The secondary hydroxyl group-containing monomer and / or tertiary hydroxyl group-containing monomer which is an a3 component have a secondary hydroxyl group or tertiary hydroxyl group which is difficult to crosslink with a crosslinking agent in a molecule | numerator. A secondary hydroxyl group containing monomer and a tertiary hydroxyl group containing monomer may add either, and may add both simultaneously.

As the secondary hydroxyl group-containing monomer,

2-hydroxypropyl (meth) acrylate,

2-hydroxybutyl (meth) acrylate,

3-hydroxybutyl (meth) acrylate,

2-hydroxy-1-ethylpropyl (meth) acrylate,

2-hydroxyhexyl (meth) acrylate,

2-hydroxycyclohexyl (meth) acrylate,

2-hydroxypentyl (meth) acrylate,

3-hydroxy-2-ethylhexyl (meth) acrylate,

3-chloro-2-hydroxypropyl (meth) acrylate,

Aliphatic epoxy acrylates can be exemplified.

As the tertiary hydroxyl group-containing monomer, 3-hydroxy-1,3-diethylbutyl (meth) acrylate can be exemplified.

The range of 1 mass%-15 mass% is preferable, and, as for the compounding ratio of a3 component in a copolymer polymer, the range of 2 mass%-10 mass% is more preferable. If the a3 component is less than 1% by mass, the number of hydroxyl groups remaining in the copolymer polymer is insufficient and the reworkability of the pressure-sensitive adhesive composition is not preferable. Moreover, when a3 component exceeds 15 mass%, a part of hydroxyl groups contained in a3 component become a crosslinking point, the crosslinking degree increases, the flexibility of a copolymer polymer falls, and rework property and adhesiveness fall, and are unpreferable.

Moreover, the mass ratio between the primary hydroxyl group containing monomer which is a2 component, and the secondary hydroxyl group containing monomer and / or tertiary hydroxyl group containing monomer which are a3 components [(secondary hydroxyl group containing monomer and / or tertiary hydroxyl group containing monomer) / (1 Class hydroxyl group-containing monomer)] is preferably 2 or more (a3 component / a2 component = 2 or more). When the mass ratio is less than 2, the number of hydroxyl groups (secondary and / or tertiary hydroxyl groups) remaining in the copolymer polymer is relatively lowered, which is not preferable because the reworkability is lowered.

(a4 ingredient)

The acrylic ester and / or methacrylic acid ester (hereinafter referred to as "(meth) acrylic acid ester") having a functional group of any one of a4 carboxyl group, epoxy group and amine group are optional components, and the degree of crosslinking of the copolymer polymer is further increased. Add when improved.

Carboxyl group-containing (meth) Specific examples of the acrylic acid ester, for example, there can be mentioned acrylic acid (H ₂ C = CHCOOH), β- carboxy ethyl acrylate _{(H 2 C = CHCOOCH 2 CH} 2 COOH).

The epoxy group-containing (meth) Specific examples of the acrylic acid ester, for example, glycidyl methacrylate may be mentioned the _{(H 2 C = CCH 3 COOCH} 2 (C 2 H 3 0)).

As a specific example of the (meth) acrylic acid ester containing an amine group, for example, N-dimethylaminoethyl acrylate (H ₂ C = CHCOOC ₂ H ₄ -N (CH ₃ ) ₂ ) or N-diethylamino Ethyl acrylate (H ₂ C═CHCOOC ₂ H ₄ —N (C ₂ H ₅ ) ₂ ) may be exemplified.

As for the compounding ratio of the a4 component in a copolymer polymer, the range of 0 mass%-5 mass% is preferable. When a4 component exceeds 5 mass%, since the crosslinking degree increases, the softness | flexibility of a copolymer polymer falls, and rework property and adhesiveness fall, it is unpreferable.

Moreover, the range of 800,000 or more and 2 million or less of the weight average molecular weight of a copolymer polymer is preferable. When the weight average molecular weight is in the range of 1 million to 1.5 million, sufficient adhesive force can be obtained as the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer of the optical member. In addition, a weight average molecular weight can be calculated | required in polystyrene conversion by gel permeation chromatography.

(Bridge)

It is preferable that the copolymer polymer (A1) is bridge | crosslinked with the crosslinking agent in the adhesive composition of this embodiment. As a crosslinking agent, it is preferable to use any 1 or more types of an isocyanate compound or a metal chelate compound.

In this case, symbol A1 is a copolymer before crosslinking, and A2 means a copolymer crosslinked by a crosslinking agent.

Moreover, when a4 component is added to a copolymer polymer, you may add another type of crosslinking agent in addition to an isocyanate compound or a metal chelate compound. That is, when a4 component is the (meth) acrylic acid ester which has a hydroxyl group, only the crosslinking agent which consists of an isocyanate compound or a metal chelate compound may be used. In addition, when a4 component is the (meth) acrylic acid ester which has a carboxyl group, what is necessary is just to add the crosslinking agent which consists of an epoxy compound further. Moreover, when a4 component is the (meth) acrylic acid ester which has an epoxy group, you may use the crosslinking agent which consists of a carboxyl group containing compound or an amine group containing compound. In addition, when a4 component is the (meth) acrylic acid ester which has an amine group, what is necessary is just to add the crosslinking agent which consists of an epoxy compound further.

The range of 0.05 mass part-5 mass parts is preferable with respect to 100 mass parts of copolymer polymers, and, as for the compounding ratio of a crosslinking agent, the range of 0.07 mass part-3 mass parts is more preferable. If the compounding ratio of a crosslinking agent is less than 0.05 mass part, since heat resistance of an adhesive composition falls, it is unpreferable, and when the compounding ratio of a crosslinking agent exceeds 5 mass parts, since flexibility of an adhesive composition falls and adhesiveness falls, it is unpreferable.

As an isocyanate compound in a crosslinking agent,

Lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate;

Alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate;

Aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate;

Trimethylolpropane / tolylene diisocyanate trimer adduct (brand name coronate L), trimethylolpropane / hexamethylene diisocyanate trimer adduct (brand name coronate HL), isocyanur of hexamethylene diisocyanate Isocyanate addition products, such as a late body (brand name coronate HX) (all are the Nippon Polyurethane Co., Ltd. product), etc. are mentioned.

Moreover, as an isocyanate compound, tolylene diisocyanate, hydrogenated tolylene diisocyanate, tolylene diisocyanate of trimethylolpropane, the xylylene diisocyanate adduct of trimethylolpropane, triphenylmethane triisocyanate, methylene Bis (4-phenylmethane) triisocyanate, isophorone diisocyanate, these ketooxime block, phenol block, etc. can also be used.

Examples of the metal chelate compound include acetylacetone and acetoacetic acid ester coordination compounds of polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium.

Examples of the epoxy compound include bisphenol A epichlorohydrin type epoxy resins, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin di or triglycidyl ether, 1 , 6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, diglycidylamine, N, N, N ', N'-tetragly Cydyl-m-xylene diamine (brand name TETRAD-X), 1,3-bis (N, N'- diglycidylaminomethyl) cyclohexane (brand name TETRAD-C) [all Mitsubishi Gaskagaku ( Note) products;

As the carboxyl group-containing compound, terminal carboxyl group-type saturated polyester resin (manufactured by Unitica Co., Ltd., "ER-8000 series"), acid pendant polyester-based adhesive resin (manufactured by Toyo Ink Co., Ltd., "Dynareo VA" -9020 ''), 1,8- octane dicarboxylic acid, methyl 1, 4- hexane dicarboxylic acid, 2, 6- naphthalene dicarboxylic acid, etc. are mentioned.

Examples of the amine group-containing compound include hexamethylene diamine, triethyl diamine, polyethylene imine, hexamethylene tetramine, diethylene triamine, triethyl tetramine, isophorone diamine, amino resin, melamine resin and the like.

As for the crosslinking degree of the copolymer polymer (A2) in an adhesive composition, 40 to 85% of range is preferable at a gel fraction, and about 70% is more preferable. If the gel fraction is in this range, the adhesive strength of the pressure-sensitive adhesive composition can be increased. In addition, a gel fraction can be calculated | required by the formula of "gel fraction = mass / initial mass # 100 after immersion drying" from the initial mass and the mass after immersion drying, when the adhesive composition is immersed in 25 degreeC ethyl acetate for 1 day.

(Other Additives)

In the pressure-sensitive adhesive composition of the present embodiment, various conventionally known antistatic agents, tackifiers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents (silane coupling agents) It can be suitably added according to the use using conventionally well-known various additives, such as an agent), an inorganic or organic filler, metal powder, powder, such as a pigment, a particulate form, and a foil-like thing. In particular, as the antistatic agent, an ionic compound or an ionic liquid compatible with the copolymer polymer can be used.

Moreover, the secondary hydroxyl group and / or tertiary hydroxyl group remain | survive in the adhesive composition of this embodiment, and these hydroxyl groups have a lone electron pair. Polarity is expressed in the adhesive composition of this embodiment by this isolated electron pair. Therefore, for example, when an ionic compound or an ionic liquid is added, surface resistance can be remarkably reduced and it becomes possible to express electroconductivity.

"Manufacturing method of adhesive composition"

As a manufacturing method of the adhesive composition of this embodiment, the various monomers of the a1 component-a3 component which are raw materials of a copolymer polymer, and a4 component as needed, for example, ethyl acetate, toluene, acetone, hexane, ketones, alcohol, etc. A copolymer polymer (A1) is prepared by mixing the organic solvent having a boiling point of about 120 ° C. or less, and further adding a polymerization initiator or the like to polymerize the monomers. The obtained copolymer polymer (A1) can be obtained in a state dissolved in an organic solvent or in a state swelled in an organic solvent.

Next, a crosslinking agent and other additives are added to the organic solvent containing the copolymer polymer (A1), and then aged to prepare a copolymer polymer (A2) having an increased degree of crosslinking. Thus, the pressure-sensitive adhesive composition of the present invention is prepared using the copolymer polymer (A2) having an increased degree of crosslinking.

The obtained pressure-sensitive adhesive composition is applied to, for example, a substrate, and then dried to form an adhesive layer. In addition, you may perform crosslinking by aging after apply | coating an adhesive composition on a base material.

`` Optical member ''

In the optical member of the present embodiment, the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition is formed on one or both surfaces of the optical sheet so as to have a thickness of about 3 to 200 m, preferably about 10 to 100 m. Formation of an adhesion layer can be performed by the method of apply | coating an adhesive composition directly to an optical sheet, the method of transferring the thing which apply | coated and formed the adhesion layer to another base material (for example, peeling liner, etc.) once.

As a coating formation method of an adhesion layer, the well-known method used for manufacture of an adhesive tape can be used, Specifically, a roll coat, a gravure coat, a reverse coat, a roll brush, a spray coat, an air knife coat, the die coat method, etc. are used. Can be mentioned.

As an optical sheet, what can be used for manufacture of various display apparatuses etc. is used, Although the kind in particular is not restrict | limited, For example, a polarizing plate, a phase difference plate, a brightness improving plate, an anti-glare sheet, etc. are included. The optical sheet may be a laminate of two or more optical materials such as a laminate of a polarizing plate and a retardation plate, a laminate of a retardation plate, a laminate of a polarizing plate and a brightness enhancement plate, or an antiglare sheet. As a polarizing plate, the thing based on the polyvinyl alcohol-type polarizing plate film, for example, and providing the protective layer to this can be used.

The adhesive strength of the adhesive layer (adhesive composition) formed on the optical sheet is preferably about 1 (N / 25 mm) to 15 (N / 25 mm), and about 5 (N / 25 mm) to about 10 (N / 25 mm). Is more preferable. When the adhesive strength is in the range of 1 to 15 (N / 25 mm), the strength becomes sufficient as the adhesive strength of the pressure-sensitive adhesive layer of the optical member. In addition, adhesive strength can be calculated | required by measuring according to the adhesive tape adhesive sheet test method of JISZ0237. Specifically, the optical member having the pressure-sensitive adhesive layer was left to stand at 23 ° C. in a 50% RH atmosphere for 7 days, and then cut into a width of 25 mm, for example, attached to a glass plate, and 50 ° C. 5 kg / cm 2 20 minutes. After carrying out autoclave treatment, a tensile tester is used, the adhesive force is measured in accordance with JIS Z0237 at a peel angle of 90 degrees and a peel rate of 0.3 m / min in a 23 ° C. and 50% RH atmosphere to evaluate the adhesive force. .

As explained above, according to the adhesive composition of this embodiment, heat resistance, heat-and-moisture resistance, and rework resistance can be improved simultaneously. Moreover, according to the adhesive composition of this embodiment, an antistatic function can be provided by adding the ionic compound and ionic liquid which are compatible with a copolymer polymer.

Moreover, according to the optical member of this embodiment, since the adhesive layer which consists of said adhesive composition is provided, the rework property, heat resistance, and damp-heat resistance of an optical member can be improved.

Example

(Adhesive composition and optical member of Example 1)

94.5 parts by mass of butyl acrylate (a1 component), 0.5 parts by mass of 4-hydroxybutyl acrylate as the primary hydroxyl group-containing monomer (a2 component) and 2-hydroxypropyl acryl as the secondary hydroxyl group-containing monomer (a3 component) 5 mass parts of rate and 140 mass parts of ethyl acetate as a solvent were injected into the flask equipped with a reflux machine and a stirrer, and it heated to 65 degreeC, carrying out nitrogen substitution. Next, 0.075 mass part of AIBN was added as a polymerization initiator, and polymerization reaction was performed over 6 hours, maintaining 65 degreeC. After completion of the polymerization reaction, 260 parts by mass of ethyl acetate was further added for viscosity adjustment, and cooled to room temperature.

Next, 0.25 mass parts of trimethylolpropane / tolylene diisocyanate trimer adduct (isocyanate type crosslinking agent, Nippon Polyurethane Co., Ltd. product, brand name coronate L) is added to the solution after cooling, Furthermore, 0.1 mass part of 3-glycidoxy propylmethyl diethoxysilane (Shin-Etsu Chemical Co., Ltd. product, brand name Shin-Etsu Silicone KBM-403) was added as a silane coupling agent, it mixed sufficiently, and it was set as the adhesive composition solution. .

The obtained pressure-sensitive adhesive composition solution was applied to a peeling PET film (Mitsubishi Chemical Co., Ltd. product, brand name MRF38) so as to have a thickness of 25 µm after drying, and aged at room temperature for 7 hours to advance the crosslinking reaction to obtain an adhesive composition. A pressure-sensitive adhesive layer was formed. And the optical member of Example 1 provided with the adhesion layer which consists of an adhesive composition of the composition shown in Table 1 by sticking an adhesion layer and peeling PET film to a polarizing plate (aesthetic imaging product, brand name MLPH).

(Adhesive composition and optical member of Examples 2 to 6)

Butyl acrylate (a1 component), 4-hydroxybutyl acrylate as a primary hydroxyl group containing monomer (a2 component), and functional groups, such as 2-hydroxypropyl acrylate and a hydroxyl group, as a secondary hydroxyl-containing monomer (a3 component) 140 parts by mass of ethyl acetate is added as a solvent to 100 parts by mass of acrylic acid as an acrylic acid ester and / or methacrylic acid ester (a4 component) as appropriate, which is injected into a flask equipped with a reflux machine and a stirrer, and nitrogen-substituted. It heated to 65 degreeC, performing the following. Next, 0.075 mass part of AIBN was added as a polymerization initiator, and polymerization reaction was performed over 6 hours, maintaining 65 degreeC. After completion of the polymerization reaction, 260 parts by mass of ethyl acetate was further added for viscosity adjustment, and cooled to room temperature.

Next, trimethylolpropane / tolylene diisocyanate trimer adduct (isocyanate type crosslinking agent, Nippon Polyurethane Co., Ltd. product, brand name coronate L) is added to the solution after cooling as a crosslinking agent, 3-glycidoxypropylmethyldiethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name Shin-Etsu Silicone KBM-403) was added as the silane coupling agent, and in Example 6, 1-hexyl was used as an antistatic agent. 3-methyl imidazolium hexafluorophosphate (made by Tokyo Kasei Co., Ltd.) was added, it mixed sufficiently, and it was set as the adhesive composition solution.

The obtained pressure-sensitive adhesive composition solution was applied to a peeling PET film (Mitsubishi Chemical Co., Ltd. product, brand name MRF38) so as to have a thickness after drying of 25 µm, and aged at room temperature for 7 hours to advance the crosslinking reaction to obtain a pressure-sensitive adhesive composition. A pressure-sensitive adhesive layer was formed. And the optical member of Examples 2-6 provided with the adhesion layer which consists of an adhesive composition of the composition shown in Table 1 by sticking an adhesion layer and a peeling PET film to a polarizing plate (aesthetics imaging product, brand name MLPH). It was.

(A pressure-sensitive adhesive composition and optical member of Comparative Examples 1 to 3)

Butyl acrylate (a1 component), 4-hydroxyl butyl acrylate as the primary hydroxyl group-containing monomer (a2 component), 2-hydroxypropyl acrylate as appropriately mixed as the secondary hydroxyl group-containing monomer (a3 component) 100 140 mass parts of ethyl acetate are added to a mass part as a solvent, and a trimethylol propane / tolylene diisocyanate trimer adduct (isocyanate type crosslinking agent, Nippon Polyurethane Co., Ltd. product, brand name Coronate L) as a crosslinking agent ) And 3-glycidoxypropylmethyldiethoxysilane (Shin-Etsu Chemical Co., Ltd. make, brand name Shin-Etsu Silicone KBM-403) suitably added as said silane coupling agent, The said Examples 2-6 In the same manner as in the above, the optical members of Comparative Examples 1 to 3 having the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition shown in Table 1 were prepared.

The obtained optical member was measured for heat resistance, moisture heat resistance, light leakage resistance, rework resistance and surface resistance values. The results are shown in Table 1 together. In addition, the order of each performance test is as follows.

<Test method of performance test>

`` Heat resistance ''

The optical member was cut | judged to the magnitude | size of 120 mm (polarizing plate MD direction) # 60 mm, and it attached to the glass plate, and performed 50 degreeC 5 kg / cm <2> 20-minute autoclave process. Then, the appearance after leaving for 120 hours in 80 degreeC atmosphere was observed, and the presence or absence of foaming, floating, or peeling was evaluated. When there was no foam etc., it was set as "good | favorableness."

`` Heat and moisture resistance ''

After the autoclave treatment, except for being left for 120 hours in an atmosphere of 60 ° C. and 90% RH, the appearance after standing was observed in the same manner as in the heat resistance test, and the presence or absence of foaming, floating or peeling was evaluated. When there was no foaming etc., it was set as "good | favorableness."

`` Light leakage ''

The optical members are cut into 120 mm (polarizing plate MD direction) ㅧ 60 mm and 120 mm (polarizing plate TD direction) ㅧ 60 mm, respectively, and placed on both sides of the glass plate so as to overlap each other. The clave process was performed. Then, the appearance after standing for 120 hours in an 80 degreeC atmosphere was observed. When light leakage was not observed, it was set as "good", and when light leakage was observed as "bad".

`` Reworkability (adhesive force and peeling state) ''

The optical member was cut | disconnected to 25 mm width, it was attached to the glass plate, and 50 degreeC <5 kg / cm <2> * 20 minutes autoclave process was performed. Thereafter, using a tensile tester, the adhesive force was measured in accordance with JIS Z0237 (adhesive tape adhesive sheet test method) under conditions of a peel angle of 90 degrees and a peel rate of 0.3 m / min in an atmosphere of 23 ° C. and 50% RH. Was performed.

In addition, the peeling state was observed at the time of the said adhesive force measurement, and the presence or absence of the electrodeposition of the adhesion layer with respect to the glass substrate was evaluated.

`` Surface Resistance Value ''

The surface resistance value of the adhesion layer of the optical member was measured in 20 degreeC and 50% RH atmosphere using the microelectrometer (made by Kawaguchi Denki Seisakusho).

The symbol in Table 1 is as follows.

BA: Butyl Acrylate

4HBA: 4-hydroxybutyl acrylate

2HPA: 2-hydroxypropyl acrylate

AA: acrylic acid

Antistatic Agent: 1-hexyl-3-methylimidazolium hexafluorophosphate (manufactured by Tokyo Kasei Co., Ltd.)

As shown in Table 1, the optical members of Examples 1 to 6 had better heat resistance, moist heat resistance, light leakage resistance, and rework resistance than Comparative Examples 1 to 3. Further, the optical member of Example 6 has a relatively low surface resistance of the pressure-sensitive adhesive layer, which makes it possible to impart antistatic performance. In Comparative Examples 1 and 2, since the a3 component was not added, heat resistance, moist heat resistance, and light leakage deteriorated. In Comparative Example 3, gelation of the solution occurred during the polymerization of the pressure-sensitive adhesive composition, and various tests were impossible.

Claims (7)

(a1) 80-98.9 weight% of acrylic acid ester or methacrylic acid ester, (a2) 0.1-5 weight% of primary hydroxyl-containing monomer which has a primary hydroxyl group in a molecule, and (a3) 2 which has a secondary hydroxyl group in a molecule A copolymer polymer in which a crosslinking agent is added to a copolymer polymer (A1) obtained by copolymerizing 1 to 15% by weight of a tertiary hydroxyl group-containing monomer or a tertiary hydroxyl group-containing monomer having a tertiary hydroxyl group to increase the degree of crosslinking of the polymer (A1) ( A2), wherein the pressure-sensitive adhesive composition, characterized in that the mass of the (a3) secondary hydroxyl group-containing monomer or tertiary hydroxyl group-containing monomer is more than twice the mass of the (a2) primary hydroxyl group-containing monomer. . delete The method of claim 1, Said crosslinking agent contains 0.05-5 weight part with respect to 100 weight part of said copolymer polymers (A1). delete The method of claim 1, The copolymer polymer (A1) is an adhesive composition, characterized in that the acrylic ester or methacrylic acid ester having a functional group of any one of a carboxyl group, an epoxy group and an amine group is contained. The method of claim 1, The crosslinking degree of the copolymer polymer (A2) having an increased crosslinking degree is an adhesive composition, characterized in that 40 to 85% based on the gel fraction. An optical member comprising the pressure-sensitive adhesive composition according to any one of claims 1, 3, 5, and 6 applied to one or both surfaces of an optical sheet.