KR20150090762A - Adhesive composition for polarizing plate, adhesive film prepared from the same, polarizing plate comprising the same and optical display comprising the same - Google Patents

Abstract

The present invention relates to: a polarizing plate adhesive composition comprising one or more of Chemical Formula 1 and Chemical Formula 2, and a potential hardening catalyst bonded with organic acid; a polarizing plate adhesive film produced from the same; a polarizing plate including the same; and an optical display device including the same.

Description

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive composition for a polarizing plate, a pressure-sensitive adhesive film for a polarizing plate formed therefrom, a polarizing plate including the same, and an optical display device including the polarizing plate.

The present invention relates to a pressure-sensitive adhesive composition for a polarizing plate, a pressure-sensitive adhesive film for a polarizing plate formed from the same, a polarizing plate comprising the same, and an optical display device comprising the same.

The liquid crystal display includes a liquid crystal panel and a polarizer attached to both sides of the liquid crystal panel, and the polarizer includes a polarizer and a protective film formed on one or both sides of the polarizer to protect the polarizer. The polarizing plate is attached to the liquid crystal panel by an adhesive film for a polarizing plate. Specifically, a pressure-sensitive adhesive composition for a polarizing plate is coated on one surface of a polarizing plate and cured to form a pressure-sensitive adhesive film for a polarizing plate, which is then attached to the liquid crystal panel.

The pressure-sensitive adhesive composition for a polarizing plate comprises a pressure-sensitive adhesive resin and a curing agent for curing the pressure-sensitive adhesive resin. The curing reaction can be partially progressed even in a liquid form before the pressure-sensitive adhesive composition is coated, whereby viscosity of the pressure-sensitive adhesive composition can be increased. This may lower the coating property of the pressure-sensitive adhesive composition and the productivity of the polarizing plate. On the other hand, after coating the pressure-sensitive adhesive composition on a polarizing plate, it is important to improve the productivity by shortening the aging period of the pressure-sensitive adhesive composition. Therefore, the pressure-sensitive adhesive composition for a polarizing plate is required to slow the curing reaction before coating to lower the viscosity increase of the pressure-sensitive adhesive composition, and to accelerate the curing of the pressure-sensitive adhesive composition after coating.

Further, since the polarizing plate is made of a film having different physical properties such as a polarizer and a protective film, when the film is exposed to high temperature and / or high humidity, each film is deformed. If the pressure-sensitive adhesive layer does not have durability under conditions of high temperature and / or high humidity, the pressure-sensitive adhesive layer or the pressure-sensitive adhesive layer may not be durable even if the polarizer is attached to the liquid- There is a floating phenomenon in which the polarizing plate is peeled from the liquid crystal panel under the condition, or bubbles are likely to be generated. This can be achieved by coating the pressure-sensitive adhesive composition on a polarizing plate and then advancing the curing, thereby shortening the aging period.

In this regard, Korean Patent Laid-Open Publication No. 2012-7003032 discloses a pressure-sensitive adhesive composition for a polarizing plate that shortens the aging period by controlling the properties of the resin itself.

A problem to be solved by the present invention is to provide a pressure-sensitive adhesive composition for a polarizing plate capable of realizing a pressure-sensitive adhesive film for a polarizing plate in which durability at high temperature and / or high humidity is excellent and no polarity plate is peeled off from the liquid crystal panel or generation of bubbles.

Another object of the present invention is to provide a pressure-sensitive adhesive composition for a polarizing plate capable of lowering the viscosity increase of the pressure-sensitive adhesive composition due to a delayed curing reaction before coating and accelerating the curing of the pressure- will be.

Another object of the present invention is to provide a pressure-sensitive adhesive composition for a polarizing plate capable of realizing a highly reliable adhesive film for a polarizing plate with a small difference in gel fraction according to aging time after coating.

The pressure-sensitive adhesive composition for a polarizing plate of the present invention may comprise at least one of the following structural formulas (1) and (2) and a latent curing catalyst to which an organic acid is bonded:

≪ Formula 1 >

(2)

(Wherein n, m, p, q, r are the same as defined in the detailed description of the present invention)

The polarizing plate of the present invention may include the above-mentioned pressure sensitive adhesive film for a polarizing plate.

The optical display device of the present invention may include the polarizing plate.

The present invention provides a pressure-sensitive adhesive composition for a polarizing plate capable of realizing a pressure-sensitive adhesive film for a polarizing plate, which prevents the polarizing plate from being lifted or bubbled from being peeled off from the liquid crystal panel at high temperature and / or high humidity.

The present invention provides a pressure-sensitive adhesive composition for a polarizing plate capable of lowering the viscosity increase of a pressure-sensitive adhesive composition due to a slow curing reaction before coating and accelerating curing of the pressure-sensitive adhesive composition after coating to shorten the aging period.

The present invention provides a pressure-sensitive adhesive composition for a polarizing plate capable of realizing a pressure-sensitive adhesive film for a polarizing plate having no difference in gel fraction after aging after coating and having high reliability.

1 is a sectional view of a polarizing plate of an embodiment of the present invention.
2 is a cross-sectional view of a polarizing plate of another embodiment of the present invention.
3 is a cross-sectional view of an optical display device according to an embodiment of the present invention.

The present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the scope of the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

As used herein, "(meth) acrylic" means acryl and / or methacrylic, "(meth) acrylate" means acrylate and / or methacrylate, 'Is not necessarily fixed to the upper and lower portions, and' upper 'may be changed to' lower 'and' lower 'may be changed to' upper 'according to the viewing time of the polarizing plate.

Hereinafter, the pressure-sensitive adhesive composition for a polarizing plate of one embodiment of the present invention will be described.

The pressure-sensitive adhesive composition for a polarizing plate of one embodiment of the present invention is used for attaching a polarizing plate to a panel of an optical display device or attaching a polarizing plate to another optical film when a polarizing plate includes an optical film formed on one side or both sides of the polarizing element At least one of the following formulas (1) and (2); And a latent curing catalyst combined with an organic acid:

≪ Formula 1 >

(Wherein n and m are each an integer of 1 to 5)

(2)

(Wherein p, q, and r are each an integer of 1 to 5).

As a result, the pressure-sensitive adhesive composition for a polarizing plate of the present invention has a short aging period, so that the polarizing plate can be prevented from being lifted or peeled off from the liquid crystal panel under high temperature and / or high humidity conditions, .

The compounds of the formulas (1) and (2) can act as a curing catalyst, but when the organic acid is bonded, not only the catalytic activity but also the viscosity change of the pressure sensitive adhesive composition can be lowered.

Specifically, the latent curing catalyst catalyzes the curing reaction between the (meth) acrylic copolymer and the curing agent as at least one of the chemical formula 1 and the chemical formula 2 and a salt of an organic acid. In the pressure-sensitive adhesive composition, the organic acid and at least one of the chemical formulas (1) and (2) are not separated and exist in a salt state, and do not catalyze the curing of the pressure-sensitive adhesive composition. As a result, the viscosity of the pressure-sensitive adhesive composition is not increased. However, in the drying condition such as high temperature after coating of the pressure-sensitive adhesive composition, the organic acid is separated from the curing catalyst, and in the aging process, at least one of the chemical formula 1 and the chemical formula 2 catalyzes the curing reaction, that is, a latent curing catalyst And the aging period of the pressure-sensitive adhesive composition can be shortened.

In embodiments, the organic acid may be separated from the curing catalyst at 80-120 < 0 > C, such that at least one of Formula I, Formula II may act as a catalyst. That is, after coating the pressure-sensitive adhesive composition, it is generally dried at 80 to 120 ° C. In this process, the organic acid is separated from the curing catalyst, and at least one of the organic acids and the organic acids represented by the formulas (1) , At least one of the formulas (1) and (2) can catalyze the aging or curing of the pressure-sensitive adhesive composition.

Thus, the pressure-sensitive adhesive composition for a polarizing plate may have a low rate of viscosity change when stored under a predetermined condition (for example, 20 to 35 ° C). For example, the pressure-sensitive adhesive composition for a polarizing plate may have a viscosity change rate (Δn) of the following formula 1 of less than 10%, specifically 5% or less, specifically 0 to 5% The viscosity can not be increased and the coating property of the pressure-sensitive adhesive composition can be good:

<Formula 1>

N = n2 - n1 / n1 x 100

(In the above formula 1, n1 is the initial viscosity (unit: cP) of 200 g of the pressure-sensitive adhesive composition at 25 캜,

and n2 is the viscosity (unit: cP) at 25 DEG C after 200 g of the pressure-sensitive adhesive composition was allowed to stand at 25 DEG C for 24 hours.

When the gel fraction according to the aging period is defined by the following formula 2, the difference between the gel fraction after 1 day of aging and the gel fraction after 7 days of aging is less than 5%, specifically 0.1 to 4% And can accelerate curing of the pressure-sensitive adhesive composition in the above range, shorten the aging period, and can be reliable.

<Formula 2>

Gel fraction = (WC-WA) / (WB-WA) x 100 (% by weight)

(In the above Equation 2, WA represents the weight of the wire mesh,

WB was prepared by applying 0.5 g of the pressure-sensitive adhesive composition to a release film to a thickness of 20 m to prepare a pressure-sensitive adhesive, aging the pressure-sensitive adhesive on the release film at 35 DEG C and 45% relative humidity for a predetermined period, After weighing,

WC is the weight of the dried adhesive and wire netting, which is obtained by adding the aged adhesive and wire netting to the sample bottle, adding 50cc of ethyl acetate and leaving for 1 day, drying at 100 ° C for 12 hours). That is, the gel fraction after one day of aging is the gel fraction measured by aging the pressure-sensitive adhesive for 1 day, and the gel fraction after 7 days of aging is the gel fraction measured by aging the pressure-sensitive adhesive for 7 days.

Specifically, the compound of Chemical Formula 1 is 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) (1,8-diazabicyclo [ , 1,5-diazabicyclo [4.3.0] non-5-ene (represented by the following formula (4) It is not limited. Specifically, the compound of Formula 2 may be 1,4-diazabicyclo [2.2.2] octane, DABCO (Formula 5), but is not limited thereto :

(3)

&Lt; Formula 4 >

&Lt; Formula 5 >

At least one of the compounds of the general formulas (1) and (2) may be contained in an amount of 0.01 to 2.0% by weight, specifically 0.05 to 1.0% by weight in the pressure-sensitive adhesive composition for a polarizing plate based on a solid content, have.

The organic acid can have a pKa of 3 to 8, excellent stability at room temperature of the curing catalyst in the above range, and less change in viscosity of the pressure-sensitive adhesive composition even at room temperature, so that stability at room temperature of the pressure- The fraction can be reduced.

As used herein, 'pKa' is the pKa value of the organic acid measured at room temperature (e.g., 25 DEG C) and water. The organic acid having a pKa of 3 to 8 is specifically a saturated or unsaturated aliphatic carboxylic acid having 1 to 20 carbon atoms having a pKa of 3 to 8, Or an aromatic carboxylic acid having a pKa of 3 to 8 and a carbon number of 6 to 30, and specifically may be at least one of octanoic acid, oleic acid, and formic acid.

The latent curing catalyst may be a commercially available product or may be prepared by reacting at least one of the compounds of the formulas (1) and (2) with an organic acid (for example, a neutralization reaction).

The latent curing catalyst may be contained in an amount of 0.1 to 2.0% by weight, specifically 0.1 to 1.0% by weight, in the pressure-sensitive adhesive composition for a polarizing plate based on a solid basis. Within this range, the effect of shortening the aging period and suppressing the viscosity change of the compounding liquid can be realized.

The latent curing catalyst may be contained in an amount of 0.01 to 2.0 parts by weight, specifically 0.05 to 1.0 part by weight based on 100 parts by weight of the (meth) acrylic copolymer, and the increase in viscosity of the pressure-sensitive adhesive composition may be suppressed in the above range.

The pressure sensitive adhesive composition for a polarizing plate may further comprise a (meth) acrylic copolymer and a curing agent.

The (meth) acrylic copolymer is cured by a curing agent to increase the mechanical strength of the pressure sensitive adhesive film for a polarizing plate. The (meth) acrylic copolymer is preferably a (meth) acrylic monomer having an alkyl group, a (meth) acrylic monomer having a carboxylic acid group, A (meth) acrylic monomer having a heterocyclic group, a (meth) acrylic monomer having an aromatic group, and a (meth) acrylic monomer having an alicyclic group. For example, the (meth) acrylic copolymer may have at least one of an alkyl group, a hydroxyl group, and a carboxylic acid group. For example, the (meth) acrylic copolymer may be a copolymer of a monomer mixture containing a (meth) acrylic monomer having an alkyl group, a (meth) acrylic monomer having a carboxylic acid group, and a (meth) acrylic monomer having a hydroxyl group.

The (meth) acrylic monomer having an alkyl group is intended to improve the reliability of the polarizing plate adhesive film and may include a linear or branched unsubstituted alkyl (meth) acrylate having an alkyl group of 1-20 carbon atoms. (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, Acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, isooctyl (meth) acrylate, hexyl (meth) acrylate, (Meth) acrylate, decyl (meth) acrylate, and dodecyl (meth) acrylate, but are not limited thereto, and they may be used singly or in combination of two or more have.

The (meth) acrylic monomer having an alkyl group may be contained in the (meth) acrylic copolymer or the monomer mixture in an amount of 70 to 99% by weight, for example 95 to 99% by weight or 90 to 97% by weight, There can be excellent effects.

The (meth) acrylic monomer having a hydroxyl group may be a (meth) acrylic acid ester having a terminal or an alkyl group having 2 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms having a hydroxyl group in the structure. (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl 1-chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, (Meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (Meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, trimethylol ethane di (meth) acrylate, 2-hydroxy- Acrylate, and cyclohexane dime (Meth) acrylate, and mono (meth) acrylate. These monomers may be used singly or in combination of two or more.

The (meth) acrylic monomer having a hydroxyl group may be contained in the (meth) acrylic copolymer or the monomer mixture in an amount of 0.1 to 10% by weight, for example, 1 to 5% by weight, for example, 1 to 4% , There can be obtained an excellent effect of reliability.

The (meth) acrylic monomer having a carboxylic acid group is intended to improve the reliability of the polarizing plate adhesive film and may mean at least one selected from the group consisting of (meth) acrylic acid and? -Carboxyethyl (meth) acrylate, They are not limited thereto, and they may be used singly or in combination of two or more.

The (meth) acrylic monomer having a carboxylic acid group may be contained in the (meth) acrylic copolymer or the monomer mixture in an amount of 0 to 10 wt%, for example, 0.01 to 10 wt%, for example, 1 to 6 wt% , There can be obtained an excellent effect of reliability.

The (meth) acrylic monomer having a heterocyclic ring may be a saturated or unsaturated aliphatic or alicyclic heterocyclic ring having 2 to 10 carbon atoms having a hetero atom (e.g., one or more of nitrogen, oxygen, sulfur) or an aromatic heterocyclic ring having 4-20 carbon atoms &Lt; / RTI &gt; For example, it may include acryloylmorpholine.

The vinyl monomer having a heterocyclic ring may be contained in an amount of 10% by weight or less, for example, 0 to 5% by weight in the (meth) acrylic copolymer or the monomer mixture. Within the above range, endurance reliability can be improved, and the rework characteristics can be good.

In one embodiment, the (meth) acrylic copolymer may be a copolymer of 95 to 99% by weight of a (meth) acrylic monomer having an alkyl group and 1 to 5% by weight of a (meth) acrylic monomer having a hydroxyl group. In another embodiment, the (meth) acrylic copolymer includes 90 to 97% by weight of a (meth) acrylic monomer having an alkyl group, 1 to 4% by weight of a (meth) acrylic monomer having a hydroxyl group, 6% by weight of the copolymer. Within the above-mentioned range, there is no decrease in durability under high temperature and high humidity conditions, light leakage phenomenon can be improved, adhesion to the panel is good, cohesive force is good, and peeling and bubbling are not caused in evaluation of durability.

The (meth) acrylic copolymer may have a weight average molecular weight of from more than 0 to 1,000,000 g / mol, for example, from 80,000 to 1,000,000 g / mol. In this range, the reliability is excellent and light leakage can be suppressed . The weight average molecular weight can be measured by gel permeation chromatography. (Meth) acrylic copolymer may have a polydispersity index (PDI) of 1.5 to 15, for example, 2 to 7. In the above range, there can be obtained an excellent effect of reliability. (Meth) acrylic copolymer may have a glass transition temperature of from -52 to -27 ° C. Within this range, it is possible to provide a good stress relaxation force to the polarizing plate, increase the adhesive force to glass, simultaneously provide high shrinkage resistance, and minimize light leakage.

The method for producing the (meth) acrylic copolymer is not particularly limited, and can be produced by a solution polymerization method, a photopolymerization method, a bulk polymerization method, an emulsion polymerization method, or an emulsion polymerization method. Preferably, the (meth) acrylic copolymer is produced by a solution polymerization method, and the polymerization temperature is preferably from 50 ° C to 140 ° C and the polymerization time is from 5 to 24 hours. As an initiator in the polymerization, an azo-based polymerization initiator such as azobisisobutyronitrile or azobiscyclohexanecarbonitrile; And / or peroxides such as benzoyl peroxide or acetyl peroxide, and the like. The initiator may be included in an amount of 0.01-10 parts by weight based on 100 parts by weight of the vinyl monomer having an alkyl group. Within this range, the copolymer can be sufficiently polymerized. The solvent for polymerization is not particularly limited, but one or more of ethyl acetate and methyl ethyl ketone may be used.

The curing agent cures the (meth) acrylic copolymer and may include one or more of isocyanate, epoxy, aziridine, melamine, amine, imide, carbodiimide, and amide.

Examples of the isocyanate-based curing agent include tolylene diisocyanate (TDI), 4,4'-methylenediphenyl diisocyanate (2,4-tolylene diisocyanate) including hexamethylene diisocyanate (HDI), 2,4-tolylene diisocyanate and 2,6- (MDI), 1,3-xylene diisocyanate, 1,4-xylene diisocyanate and the like, hydrogenated tolylene diisocyanate, isoform diisocyanate, 1,3-bisisocyanatomethylcyclo Hexane, hexane, tetramethylxylylene diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, trimethylolpropane- Diisocyanate, trimethylolpropane-modified tolylene diisocyanate, trimethylolpropane tolylenediisocyanate Bit control duct, trimethylolpropane and the like xylene diisocyanate air duct, triphenylmethane triisocyanate, methylene bis triisocyanate of propane, but are not necessarily limited thereto. These may be used alone or in combination of two or more.

The curing agent may be contained in an amount of 0.1 to 5 parts by weight, specifically 0.1 to 1 part by weight, based on 100 parts by weight of the (meth) acrylic copolymer. In this range, the pressure-sensitive adhesive is excellent in endurance reliability, Can be written down.

Since the curing agent is catalyzed by the latent curing catalyst, it is important to control the content of the curing agent and the latent curing catalyst. Specifically, the weight ratio of the curing agent to the latent curing catalyst in the pressure-sensitive adhesive composition may be 1: 0.1 to 1: 1.0, and the viscosity increase in the pressure-sensitive adhesive composition may be lowered in the above range, .

The pressure-sensitive adhesive composition for a polarizing plate may further comprise a silane coupling agent. The silane coupling agent is contained in the pressure-sensitive adhesive composition, so that the moisture-proof and moisture-wet heat reliability of the pressure-sensitive adhesive film for a polarizing plate can be enhanced.

As the silane coupling agent, those conventionally known to those skilled in the art can be used. For example, silicon compounds having an epoxy structure such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; A polymerizable unsaturated group-containing silicon compound such as vinyltrimethoxysilane, vinyltriethoxysilane and (meth) acryloxypropyltrimethoxysilane; Containing silicon compounds such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane. ; And 3-chloropropyltrimethoxysilane, and the like, but are not limited thereto. Preferably, a silane coupling agent having an epoxy structure can be used.

The silane coupling agent may be contained in an amount of 0.1 to 5 parts by weight, specifically 0.1 to 1 part by weight, based on 100 parts by weight of the (meth) acrylic copolymer. The pressure-sensitive adhesive of the present invention is excellent in endurance reliability, Change can be small.

The pressure-sensitive adhesive composition for a polarizing plate may further include a solvent. The solvent is not particularly limited, but methyl ethyl ketone and the like can be used. The pressure-sensitive adhesive composition may further contain conventional additives such as an ultraviolet absorber and an antioxidant.

The pressure-sensitive adhesive composition for a polarizing plate may further include a conventional curing catalyst, for example, a tin-containing catalyst, contained in the pressure-sensitive adhesive composition for a polarizing plate.

The pressure-sensitive adhesive composition for a polarizing plate may have a viscosity of 1,000 to 6,000 cP at 25 ° C. Within the above range, the thickness of the adhesive film can be easily adjusted, there is no unevenness in the adhesive film, and the coated surface can have a uniform effect.

Hereinafter, the pressure-sensitive adhesive film for a polarizing plate of one embodiment of the present invention will be described.

The pressure-sensitive adhesive film for a polarizing plate can be produced by drying and / or aging the pressure-sensitive adhesive composition for a polarizing plate of one embodiment of the present invention. Specifically, aging of the pressure-sensitive adhesive composition may include, but is not limited to, thermosetting, or leaving at 20 to 35 占 폚 for 1 hour to 1 week. For example, the pressure-sensitive adhesive film can be produced by coating the pressure-sensitive adhesive composition on a release film (for example, a polyethylene terephthalate film), followed by drying and curing at 20 to 35 ° C.

The adhesive film for a polarizing plate may have a peel strength of 0.1 to 1.0 kgf / 25 mm, for example, 0.15 to 0.6 kgf / 25 mm as measured by JIS 2107 or ASTM D3330 / D3330M. In the above range, It is possible to provide a polarizing plate which can be adhered well to the polarizing plate, is easily reattached, and is excellent in reliability.

The thickness of the pressure sensitive adhesive film for a polarizing plate may be 5 to 100 탆, and within the above range, the pressure sensitive adhesive film for a polarizing plate may be used.

The pressure-sensitive adhesive film for a polarizing plate may have an acid value of 12 mgKOH / g or less, specifically 6 to 8 mgKOH / g. In this range, a polarizer excellent in reliability can be provided.

The polarizing plate of the present invention comprises an adhesive layer for a polarizing plate of one embodiment of the present invention or an adhesive layer formed of a pressure-sensitive adhesive composition for a polarizing plate of one embodiment of the present invention. Specifically, the polarizing plate may include a polarizer, an optical film formed on one side or both sides of the polarizer, and an adhesive film for a polarizing plate formed on one side of the optical film. The optical film may include at least one of a non-phase difference protective film and a retardation film. Hereinafter, a polarizing plate of one embodiment of the present invention will be described with reference to Fig.

Referring to FIG. 1, a polarizer 100 of one embodiment of the present invention includes a polarizer 1; A first protective film 2 formed on the upper portion of the polarizer 1; A second protective film 3 formed on the lower portion of the polarizer 1; And a first adhesive film 4 formed on the lower part of the second protective film 3. The first adhesive film 4 may be formed of the adhesive film or the adhesive composition of the present invention.

The polarizer is made of a polyvinyl alcohol-based film and is not particularly limited as long as it is a polyvinyl alcohol-based film regardless of the manufacturing method. For example, a polarizer may be a modified polyvinyl alcohol film such as a partially-formalized polyvinyl alcohol film or an acetoacetyl-modified polyvinyl alcohol film. Specifically, a polyvinyl alcohol film is prepared by dyeing iodine or a dichroic dye and stretching it in a predetermined direction. Specifically, it is produced through a swelling process, a dyeing process, and a stretching process. Methods of performing each step are commonly known to those skilled in the art. Although the thickness of the polarizer is not particularly limited, it may be, for example, 10 占 퐉 to 50 占 퐉, and it may be used in an optical display device in the above range.

The first protective film and the second protective film may be laminated on one side of the polarizer, respectively. The first protective film and the second protective film may be the same or different and may be selected from the group consisting of a cyclic polyolefin-based material including a cyclic olefin polymer (COP), a poly (meth) acrylate-based, a polycarbonate-based, Polyamide, polyimide, polyolefin, polyarylate, polyvinyl alcohol, polyvinyl chloride, polyvinyl chloride, polyvinylidene chloride, polyvinylidene chloride, Ternary or a mixture thereof.

Thicknesses of the first protective film and the second protective film are not particularly limited, but may be 10 占 퐉 to 200 占 퐉, for example, 30 占 퐉 to 120 占 퐉, respectively.

The adhesive film may be formed by coating the adhesive composition of one embodiment of the present invention on one side of the protective film, drying and / or curing the adhesive film, and the thickness of the adhesive film may be 5 to 100 탆.

Although not shown in Fig. 1, the adhesive film 4 is laminated on one surface of a liquid crystal display panel (not shown in Fig. 1) to fix the polarizing plate to the liquid crystal display panel.

1, an adhesive layer may be formed between the polarizer 1 and the first protective film 2 and between the polarizer 1 and the second protective film 3, And may be formed of an adhesive for a polarizing plate. Specifically, the adhesive for a polarizing plate may include an aqueous adhesive including a polyvinyl alcohol resin, and a photo-curable adhesive including a (meth) acrylic adhesive resin.

Hereinafter, the polarizing plate of another embodiment of the present invention will be described with reference to Fig. 2 is a sectional view of a polarizing plate of another embodiment of the present invention.

Referring to FIG. 2, the polarizing plate 200 of another embodiment of the present invention includes a polarizer 1; A first protective film 2 formed on the upper surface of the polarizer 1; A second protective film 3 formed on the lower surface of the polarizer 1; A first adhesive film (4) formed on the lower surface of the second protective film (3); A third protective film 5 formed on the lower surface of the first adhesive film 4; And a second adhesive film 6 laminated on the lower surface of the third protective film 5 and at least one of the first adhesive film 4 and the second adhesive film 6 is used for a polarizing plate May be formed of a pressure-sensitive adhesive composition. Except that a third protective film and a second adhesive film are further formed on the lower surface of the first adhesive film.

The third protective film may be a polyester-based film including a cyclic olefin polymer including a cyclic olefin polymer (COP), a poly (meth) acrylate, a polycarbonate, and a polyethylene terephthalate (PET) , A polyether sulfone system, a polysulfone system, a polyamide system, a polyimide system, a polyolefin system, a polyarylate system, a polyvinyl alcohol system, a polyvinyl chloride system, a polyvinylidene chloride system or a mixture thereof. Although the thickness of the protective film is not particularly limited, it may be 10 占 퐉 to 200 占 퐉, for example, 30 占 퐉 to 120 占 퐉, and it may be used in an optical display device in the above range.

Although not shown in Fig. 2, the second adhesive film 6 is laminated on one surface of a liquid crystal display panel (not shown in Fig. 2) to fix the polarizing plate to the liquid crystal display panel.

The display device of the present invention may include the adhesive film or the polarizing plate. The display device may include, but is not limited to, a liquid crystal display device or the like including a TFT-LCD or the like.

Hereinafter, an optical display device according to one embodiment of the present invention will be described with reference to FIG. 3 is a cross-sectional view of an optical display device according to an embodiment of the present invention.

3, an optical display 300 according to an embodiment of the present invention includes a liquid crystal display panel 310, a first polarizer 320 formed on the upper surface of the liquid crystal display panel 310, and a liquid crystal display panel 310, And a second polarizer 330 formed between the liquid crystal display panel 310 and the light source unit 340. One or more of the first polarizer 320 and the second polarizer 330 may be disposed on the lower surface of the liquid crystal display panel 310, It can be a polarizing plate.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Manufacturing example  One:( Meta ) Preparation of Acrylic Copolymer

97 parts by weight of n-butyl acrylate (BA), 1 part by weight of 2-hydroxyethylacrylate (2-HEA), 1 part by weight of acrylic acid (AA), and the like were charged in a 1 L reactor equipped with a cooling device, ) And 100 parts by weight of ethyl acetate (EA) as a solvent. After that, the reactor was replaced with nitrogen gas for 1 hour to remove oxygen, and the temperature was maintained at 62 ° C. After homogeneously stirring the monomer mixture, 0.07 part by weight of azobisisobutyronitrile (AIBN) as a reaction initiator was added and reacted for 8 hours to prepare an acrylic copolymer A having a weight average molecular weight of 800,000 to 1,000,000 g / mol .

Manufacturing example  2 to 3 :( Meta ) Preparation of acrylic copolymer

Acrylic copolymers B and C were produced in the same manner as in Production Example 1, except that the content ratio was changed to the following Table 1 (unit: parts by weight).

Copolymer BA 2-HEA AA [Manufacturing Example 1] A 97 One 2 [Preparation Example 2] Preparation of B 99 One - [Manufacturing 3] C 94 One 5

Example  One

On the basis of the solid content, 100 parts by weight of the acrylic copolymer of Production Example 1, 1 part by weight of a modified isocyanate curing agent (Coronate-L, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a curing agent, and 3 parts by weight of 3-glycidoxypropyltrimethoxysilane (KBM-403, Shin-Etsu), 0.5 parts by weight of a DBU / organic acid salt (1,8-Diazabicycloundec-7-ene / octanoic acid slat, SA-102, SAN-APRO) as a latent curing catalyst, The mixture was diluted to a concentration of 20% and stirred for 30 minutes to prepare a pressure-sensitive adhesive composition for a polarizing plate.

The prepared pressure-sensitive adhesive composition for a polarizing plate was coated on a release film (for example, polyethylene terephthalate film) and dried at 100 ° C for 3 minutes to form a pressure-sensitive adhesive film having a thickness of 20 μm. The pressure-sensitive adhesive film for a polarizing plate was laminated on a polarizing plate and aged under constant temperature and humidity conditions (35 DEG C, 45% relative humidity).

Example  2 to 7

The procedure of Example 1 was repeated except that the kind of the (meth) acrylic copolymer, the kind and content of the latent curing catalyst, and the content of the silane coupling agent in Example 1 were changed as shown in Table 2 (unit: parts by weight) A pressure-sensitive adhesive composition for a polarizing plate was prepared in the same manner.

The prepared pressure-sensitive adhesive composition for a polarizing plate was coated on a release film (for example, polyethylene terephthalate film) and dried at 100 ° C for 3 minutes to form a pressure-sensitive adhesive film having a thickness of 20 μm. The pressure-sensitive adhesive film for a polarizing plate was laminated on a polarizing plate and aged under constant temperature and humidity conditions (35 DEG C, 45% relative humidity).

Comparative Example  One

A pressure-sensitive adhesive composition for a polarizing plate was prepared in the same manner as in Example 1, except that the curing catalyst was not used in Example 1.

Comparative Example  2

A pressure-sensitive adhesive composition for a polarizing plate was prepared in the same manner as in Example 1, except that the TIN catalyst was used as the curing catalyst in Example 1.

Comparative Example  3

A pressure-sensitive adhesive composition for a polarizing plate was prepared in the same manner as in Example 1, except that DBU was used as a curing catalyst in Example 1.

Comparative Example  4

A pressure-sensitive adhesive composition for a polarizing plate was prepared in the same manner as in Example 1, except that an organic acid (octanoic acid) was used instead of the DBU / organic acid salt in Example 1.

Example Comparative Example One 2 3 4 5 6 7 One 2 3 4 Copolymer Kinds A A A A A B C A A A A Weight portion 100 100 100 100 100 100 100 100 100 100 100 Hardener One One One One One One One One One One One Silane coupling agent 0.5 0.5 0.5 0.5 0.5 0.5 - 0.5 0.5 0.5 0.5 Curing catalyst SA-102 (DBU / octanoic acid salt) 0.5 - - 0.1 1.0 0.5 0.5 - - - - SA-106 (DBU / oleic acid salt) - 0.5 - - - - - - - - - SA-603 (DBU / formic acid salt) - - 0.5 - - - - - - - - dibutyltin dilaurate
(DBTDL) - - - - - - - - 0.5 - - DBU - - - - - - - - - 0.5 - octanoic acid - - - - - - - - - - 0.5 Curing agent: Coronate L, manufactured by Nippon Polyurethane Co.
Silane coupling agent: 3-glycidoxypropyltrimethoxysilane (KBM-403, Shin-Etsu Chemical Industry Co., Ltd.)
Curing catalyst: DBU SALT (SAN-APRO)

The following properties were evaluated for the pressure-sensitive adhesive composition for a polarizing plate of Examples and Comparative Examples, and the pressure-sensitive adhesive film prepared by coating and curing therefrom, and the results are shown in Table 3.

division Example Comparative Example One 2 3 4 5 6 7 One 2 3 4 PKa of organic acids 4.89 5.02 3.75 4.89 4.89 4.89 4.89 - - - 4.89 Peel strength
(kgf / 25 mm) 0.19 0.21 0.18 0.25 0.18 0.16 0.24 1.17 0.54 0.14 0.17 Viscosity change rate (%) 3.7 4.2 2.4 1.9 4.8 1.1 3.4 2.1 4.7 28.4 12.4 Viscosity change of compounded liquid ○ ○ ○ ○ ○ ○ ○ ○ ○ × △ Gel fraction (%) after 1 day of aging 79.1 77.6 81.9 75.9 82.1 81.2 78.4 32.6 52.8 84.7 72.4 Gel fraction (%) after 7 days of aging 82.1 81.0 82.7 79.3 83.8 82.3 80.3 79.6 82.3 86.2 82.9 Gel fraction difference (%) 3.0 3.4 0.8 3.4 1.7 1.1 1.9 47.0 29.5 1.5 10.5 Intrinsic reliability ○ ○ ○ ○ ○ ○ ○ × △ △ △ Heat Resistance Reliability ○ ○ ○ ○ ○ ○ ○ × × △ ○

(1) Peel strength: The 180 占 peeling force between the adhesive film and the glass substrate was measured by the method specified in JIS 2107. [ The adhesive film was cut into 25 mm x 200 mm (width X length) and attached to the glass surface. Each of them was connected to the upper and lower jig of the adhesive film and the glass substrate in a load cell of 30 kgf using a texture analyzer and then subjected to peeling at 180 ° peeling rate at a tensile speed of 300 mm / min Were measured.

(2) Change in Viscosity of Compounded Liquid: 200 g of the pressure-sensitive adhesive composition after blending was measured for initial viscosity at 25 캜, and 200 g of the pressure-sensitive adhesive composition was allowed to stand at 25 캜 for 24 hours and then the viscosity at 25 캜 was measured. n) was calculated according to the following formula 1, and the viscosity change rate was evaluated based on the following criteria. The viscosity was measured with a Brookfield viscometer of LV type.

<Formula 1>

N = n2 - n1 / n1 x 100

(In the above formula 1, n1 is the initial viscosity (unit: cP) of 200 g of the pressure-sensitive adhesive composition at 25 캜,

and n2 is the viscosity (unit: cP) at 25 DEG C after 200 g of the pressure-sensitive adhesive composition was allowed to stand at 25 DEG C for 24 hours.

<Evaluation Criteria>

?: 5%??? N <10%

?: 10%??? N <20%

X: 20%?? N

(3) Gel fraction: The gel fraction is measured according to the following formula 2, and the gel fraction difference is evaluated.

<Formula 2>

Gel fraction = (WC-WA) / (WB-WA) x 100

(In the above Equation 2, WA represents the weight of the wire mesh,

WB was prepared by applying 0.5 g of the pressure-sensitive adhesive composition to a release film to a thickness of 20 m to prepare a pressure-sensitive adhesive, aging the pressure-sensitive adhesive on the release film at 35 DEG C and 45% relative humidity for a predetermined period of time, After weighing,

WC is the weight of the dried adhesive and wire mesh, which is obtained by adding the aged adhesive and wire netting to the sample bottle, adding 50cc of ethyl acetate and allowing to stand for 1 day, drying at 100 ° C for 12 hours). That is, the gel fraction after one day of aging is the gel fraction measured by aging the pressure-sensitive adhesive for 1 day, and the gel fraction after 7 days of aging is the gel fraction measured by aging the pressure-sensitive adhesive for 7 days. The gel fraction after 1 day of aging and the gel fraction after 7 days of aging are obtained. Further, when the difference in the gel fraction is less than 5%, it is evaluated that the aging of the pressure-sensitive adhesive composition is completed. A polyethylene terephthalate film (thickness: 38 mu m) was used as a release film, and a 100 mL block bottle was used as a sample bottle, and 200 mesh was used as a wire mesh.

(4) durability: the examples and comparative examples, a pressure-sensitive adhesive composition is coated polarizer (100mm x 80mm, length x width) prepared in the specimen attached to the both surfaces of the glass substrate and applying a pressure of 4-5 kg / cm ² Respectively. The heat resistance of the prepared specimens was evaluated by observing the occurrence of bubbles or peeling after standing at 85 ° C for 250 hours. The humidity resistance and the heat resistance reliability were evaluated by observing whether bubbles or peeling occurred after standing for 250 hours at a temperature of 60 ° C and a relative humidity of 95%. The evaluation criteria are as follows.

○: No bubbles or peeling

△: There are some bubbles or peeling.

X: There is bubble or peeling.

As shown in Table 3, the pressure-sensitive adhesive film and the pressure-sensitive adhesive composition for a polarizing plate of the present invention had a low rate of change in viscosity in the blended state, and the coating properties of the pressure-sensitive adhesive composition were high. Instead, the gel fraction, It was confirmed that the difference in the post gel fraction was remarkably low to shorten the time required for aging to improve the processability and to provide excellent durability at high temperature and / or high humidity.

On the other hand, Comparative Example 1, which did not contain an organic acid salt, took a long time for aging due to a large difference in gel fraction, and the moisture and / or moisture proof reliability was also poor. Comparative Example 2 containing a tin compound used as a conventional curing catalyst had a problem that the gel fraction was greatly changed, and Comparative Examples 3 and 4 including DBU alone or organic acid alone had a high viscosity change rate.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (12)

At least one of the following formulas (1) and (2); And a latent curing catalyst having an organic acid bonded thereto:
&Lt; Formula 1 >

(Wherein n and m are each an integer of 1 to 5)
(2)

(Wherein p, q, and r are each an integer of 1 to 5). The pressure-sensitive adhesive composition for a polarizing plate according to claim 1, wherein the organic acid has a pKa of 3 to 8. The pressure-sensitive adhesive composition for a polarizing plate according to claim 1, wherein the organic acid comprises at least one of octanoic acid, oleic acid, and formic acid. The method of claim 1, wherein the compound of Formula 1 is 1,8-diazabicyclo [5.4.0] undec-7-ene, 5-diazabicyclo [4.3.0] non-5-ene (1,5-diazabicyclo [4.3.0] non-5-ene). The pressure-sensitive adhesive composition for a polarizing plate according to claim 1, wherein the compound of formula (2) is 1,4-diazabicyclo [2.2.2] octane. The pressure-sensitive adhesive composition for a polarizing plate according to claim 1, wherein the latent curing catalyst is contained in an amount of 0.01 to 2.0% by weight based on the solid content of the pressure-sensitive adhesive composition for a polarizing plate. The pressure-sensitive adhesive composition for a polarizing plate according to claim 1, wherein the pressure-sensitive adhesive composition for a polarizing plate further comprises a (meth) acrylic copolymer and a curing agent. The pressure-sensitive adhesive composition for a polarizing plate according to claim 7, wherein the (meth) acrylic copolymer has at least one of an alkyl group, a hydroxyl group and a carboxylic acid group. The pressure-sensitive adhesive composition for a polarizing plate according to claim 7, wherein the pressure-sensitive adhesive composition for a polarizing plate further comprises a silane coupling agent. The pressure-sensitive adhesive composition for a polarizing plate according to claim 1, wherein the pressure-sensitive adhesive composition for a polarizer has a viscosity change rate (? N) of less than 10%
<Formula 1>
N = n2 - n1 / n1 x 100
(In the above formula 1, n1 is the initial viscosity (unit: cP) of 200 g of the pressure-sensitive adhesive composition at 25 캜,
and n2 is the viscosity (unit: cP) at 25 DEG C after 200 g of the pressure-sensitive adhesive composition was allowed to stand at 25 DEG C for 24 hours. A pressure-sensitive adhesive film for a polarizing plate formed from the pressure-sensitive adhesive composition for a polarizing plate according to any one of claims 1 to 10. An optical display device comprising the pressure-sensitive adhesive film for a polarizing plate according to claim 11.

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