KR20140031116A - Adhesive composition - Google Patents

Abstract

The present invention relates to an adhesive composition, and more specifically, to an adhesive composition which includes a primary alcohol group-containing acrylic copolymer, a secondary alcohol group-containing acrylic copolymer, a toluene diisocyanate-based crosslinking agent, and an aliphatic isocyanate-based crosslinking agent. The adhesive composition prevents leak of light by overcoming bending characteristics due to stress relaxation, improved durability, does not contain an anti-corrosive agent, and can effectively suppress the corrosion of a metal layer.

Description

[0001] ADHESIVE COMPOSITION [0002]

The present invention relates to a pressure-sensitive adhesive composition excellent in preventing light leakage due to stress concentration and at the same time excellent durability and corrosion protection of the metal.

In general, a liquid crystal display device (LCD) is provided with a liquid crystal cell and a polarizing plate containing a liquid crystal, and an appropriate pressure-sensitive adhesive layer for bonding them is used.

In order to protect the polarizer and the polarizer, the polarizing plate is laminated with protective films such as triacetyl cellulose (TAC). In addition, it may additionally include a wide viewing angle compensation film and a functional film.

At this time, each film is made of a material having a different molecular structure and composition and thus have different physical properties. In particular, under high temperature or high temperature and high humidity conditions, dimensional stability due to shrinkage or expansion of materials having a unidirectional molecular arrangement is insufficient. Therefore, when the polarizing plate is fixed by the pressure-sensitive adhesive, stress is concentrated in the TAC layer by contraction or expansion of the polarizing plate under high temperature or high temperature and high humidity conditions, and thus the polarizing plate is bent, which causes a light leakage phenomenon.

Such warpage can be suppressed by adjusting the stress relaxation property of the pressure-sensitive adhesive fixed to the polarizing plate so that residual stress does not remain, and this can be achieved when the pressure-sensitive adhesive is a low-cost bridge.

Accordingly, a crosslinkable copolymer, a noncrosslinkable copolymer, and a crosslinking agent are contained, and an adhesive having a SEMI-INTER PENETRATING NETWORK structure has been proposed [Korean Patent No. 948,778]. The pressure-sensitive adhesive is excellent in fluidity and stress relaxation characteristics, but recently there was a limit that does not show the durability suitable for the trend of the size of the polarizing plate and thinning.

In addition, a pressure-sensitive adhesive having an INTER PENETRATING NETWORK structure containing a crosslinkable copolymer, a crosslinking agent, a polyfunctional acrylate monomer and a photoinitiator has been proposed [Korean Patent No. 983,026]. The pressure-sensitive adhesive is able to implement the durability that can satisfy the recent trend, but it is difficult to secure the stress relaxation property there was a limit that warpage occurs.

The present invention is to provide a pressure-sensitive adhesive composition capable of effectively suppressing the corrosion of the metal layer without containing a corrosion inhibitor component and excellent durability, and also prevents light leakage phenomenon by reducing the occurrence of warpage by stress relaxation. .

In order to achieve the above object, the present invention provides an adhesive composition containing an acrylic copolymer having a primary alcohol group, an acrylic copolymer having a secondary alcohol group, a tolylene diisocyanate crosslinking agent and an aliphatic isocyanate crosslinking agent.

The acrylic copolymer having the primary alcohol group may be copolymerized by containing at least one monomer selected from Formulas 1 to 5 below.

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 2 to 12)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 12)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)

Wherein R ₁ is a hydrogen atom or a methyl group

(Wherein R ₁ is a hydrogen atom or a methyl group).

The acrylic copolymer having a primary alcohol group may contain a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and at least one monomer selected from Formulas 1 to 5.

The at least one monomer selected from Formulas 1 to 5 may contain 0.1 to 10 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms.

The acrylic copolymer having the secondary alcohol group may be copolymerized by containing at least one monomer selected from the following formulas (6) to (9).

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)

The acrylic copolymer having a secondary alcohol group may contain a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and at least one monomer selected from Formulas 6 to 9.

The at least one monomer selected from Formulas 6 to 9 may contain 0.01 to 5 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms.

60 to 95 parts by weight of the acrylic copolymer having a primary alcohol group, 5 to 40 parts by weight of an acrylic copolymer having a secondary alcohol group, 0.1 to 5 parts by weight of toluene diisocyanate crosslinking agent and 0.01 to 1 weight of aliphatic isocyanate crosslinking agent It may contain a part.

The pressure-sensitive adhesive composition of the present invention has the advantage of excellent durability as well as preventing light leakage due to stress concentration by reducing the occurrence of warpage by stress relaxation.

In addition, the pressure-sensitive adhesive composition of the present invention has an advantage that it can effectively inhibit the corrosion of the metal layer without containing any corrosion inhibitor component.

Therefore, the pressure-sensitive adhesive composition is expected to have high utility in fields such as polarizing plates and liquid crystal displays.

The present invention relates to a pressure-sensitive adhesive composition excellent in preventing light leakage due to stress concentration and at the same time excellent durability and corrosion protection of the metal.

Hereinafter, the present invention will be described in detail.

The pressure-sensitive adhesive composition of the present invention contains an acrylic copolymer having a primary alcohol group, an acrylic copolymer having a secondary alcohol group, a tolylene diisocyanate crosslinking agent and an aliphatic isocyanate crosslinking agent.

According to the present invention, an acrylic copolymer having a primary alcohol group and an acrylic copolymer having a secondary alcohol group form an inter penetrating network (IPN) structure.

Specifically, according to the present invention, a crosslinking reaction is performed between a single type of acrylic copolymer by the relative steric hindrance of the crosslinking agent and the acrylic copolymer and the difference in the reaction rate of the crosslinking agent, and they are infiltrated between the crosslinked acrylic copolymers to form an IPN structure. To form.

The present invention does not use radical crosslinking of a polyfunctional acrylate for forming an existing IPN structure, and forms an IPN structure by applying only urethane crosslinking having a small number of crosslinking functional groups and a relatively long crosslinking length, thereby forming an adhesive of a conventional IPN structure. Compared with the composition, the stress relaxation property is improved and at the same time, the durability is excellent.

The acrylic copolymer having a primary alcohol group is copolymerized by containing at least one monomer selected from the following formulas (1) to (5). At least one monomer selected from Formulas 1 to 5 is a crosslinkable monomer component that enhances cohesion or adhesive strength of the pressure-sensitive adhesive composition by chemical bonding to impart durability and cutting property.

[Chemical Formula 1]

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 2 to 12)

(2)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 12)

(3)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)

[Chemical Formula 4]

Wherein R ₁ is a hydrogen atom or a methyl group

[Chemical Formula 5]

(Wherein R ₁ is a hydrogen atom or a methyl group).

Considering the durability, stress relaxation property, etc. of an adhesive composition at the same time, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylamide, hydride Preference is given to using oxymethyl (meth) acrylamide and the compound of formula (4).

It is preferable that the acryl-type copolymer which has a primary alcohol group of this invention contains the (meth) acrylate monomer which has a C1-C12 alkyl group, and 1 or more types of monomers chosen from the said Formula (1-5). In the present invention, (meth) acrylate means acrylate and methacrylate.

Examples of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms include n-butyl (meth) acrylate, 2-butyl (meth) acrylate, t-butyl (meth) acrylate, and 2-ethylhexyl (meth). ) Acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, propyl (meth) acrylate, pentyl (meth) acrylate, n-octyl (meth) acrylate, Isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, and the like, among which n-butyl acrylate, 2-ethylhexyl acrylate or Mixtures of these are preferred. These may be used alone or in combination of two or more.

At least one monomer selected from Formulas 1 to 5 is preferably included in an amount of 0.1 to 10 parts by weight, more preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms. Madam is good. When the content is less than 0.1 part by weight, the cohesive force of the pressure-sensitive adhesive becomes small and durability may be deteriorated. When the content is more than 10 parts by weight, a high gel fraction may deteriorate the adhesive strength and cause durability problems.

The acrylic copolymer of the present invention may further contain other polymerizable monomers other than the above monomers in a range not lowering the adhesive force, for example, 10 parts by weight or less based on the total amount.

The method for producing the copolymer is not particularly limited and can be produced by methods such as bulk polymerization, solution polymerization, emulsion polymerization or suspension polymerization, which are commonly used in the art, and solution polymerization is preferable. In addition, a solvent, a polymerization initiator, a chain transfer agent for molecular weight control and the like which are usually used in polymerization can be used.

The acrylic copolymer preferably has a weight average molecular weight (polystyrene conversion, Mw) of 50,000 to 2,000,000, more preferably 400,000 to 2,000,000 as measured by Gel Permeation Chromatography (GPC). When the weight-average molecular weight is less than 50,000, cohesion between co-polymers may be insufficient, which may cause problems in adhesion durability. If the weight average molecular weight is more than 2,000,000, a large amount of a diluting solvent may be required in order to ensure fairness in coating.

It is preferable to contain 60-95 weight part with respect to 100 weight part of adhesive compositions, and, as for the acrylic copolymer which has such a primary alcohol group, 70-90 weight part is more preferable. If the content is less than 60 parts by weight may be insufficient durability, if it exceeds 95 parts by weight may be insufficient stress relaxation characteristics.

The acrylic copolymer having a secondary alcohol group is copolymerized by containing at least one monomer selected from the following formulas (6) to (9). At this time, the monomer of Formula 2 also serves as a crosslinkable monomer.

[Chemical Formula 6]

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)

[Formula 7]

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)

[Formula 8]

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)

[Chemical Formula 9]

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)

Among these, in consideration of durability, stress relaxation property, and the like of the pressure-sensitive adhesive composition, 2-hydroxypropyl (meth) acrylate or 3-phenoxy-2-hydroxypropyl acrylate is preferable, and 2-hydroxypropyl (meth) ) Acrylate is more preferred.

It is preferable that the acryl-type copolymer which has a secondary alcohol group of this invention contains the (meth) acrylate monomer which has a C1-C12 alkyl group, and 1 or more types of monomers chosen from the said Formulas 6-9.

The at least one monomer selected from Formulas 6 to 9 is preferably included in an amount of 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms. Madam is good. If the content is less than 0.01 parts by weight, the cohesive force of the pressure-sensitive adhesive may be reduced, the durability may be lowered.

In addition, the kind of the (meth) acrylate monomer which has a C1-C12 alkyl group, the polymerization method, the weight average molecular weight of the produced acrylic copolymer, etc. are the same as the copolymer which has the said primary alcohol group.

It is preferable to contain 5-40 weight part with respect to 100 weight part of adhesive compositions, and, as for the acrylic copolymer which has such a secondary alcohol group, 10-30 weight part is more preferable. If the content is less than 5 parts by weight, the stress relaxation performance may be insufficient, and if it exceeds 40 parts by weight, durability may be reduced.

The tolylene diisocyanate crosslinking agent and the aliphatic isocyanate crosslinking agent are components for enhancing the cohesive force of the pressure-sensitive adhesive by appropriately crosslinking the acrylic copolymer.

The tolylene diisocyanate-based crosslinking agent is involved in the crosslinking reaction of the acrylic copolymer having a primary alcohol group. Specifically, it may be in the form of an adduct of tolylene diisocyanate, isocyanurate thereof or polyhydric alcohol.

It is preferable that such tolylene diisocyanate type crosslinking agent contains 0.1-5 weight part with respect to 100 weight part of adhesive compositions. If the content is less than 0.1 part by weight may be a decrease in durability, if the content exceeds 5 parts by weight may be a concern of simultaneous degradation of durability and stress relaxation properties.

The aliphatic isocyanate crosslinking agent is involved in the crosslinking reaction of the acrylic copolymer having a secondary alcohol group. Specifically, it may be an adduct form of hexamethylene diisocyanate-based and isophorone diisocyanate-based, isocyanurate-based or polyhydric alcohols thereof.

It is preferable to contain 0.01-1 weight part of such aliphatic isocyanate type crosslinking agents with respect to 100 weight part of adhesive compositions. If the content is less than 0.01 parts by weight may be a decrease in durability, if more than 1 part by weight may be a concern of the stress relaxation resistance.

In addition to the above components, the pressure-sensitive adhesive composition may further contain various additives such as a silane coupling agent, a tackifier resin, an antioxidant, a leveling agent, a surface lubricant, a dye, an antioxidant, and the like in order to control the adhesion, cohesion, viscosity, A pigment, a defoaming agent, a filler, a light stabilizer, an antistatic agent, and the like.

The double silane coupling agent serves to improve the adhesion between the pressure-sensitive adhesive and the substrate. Therefore, it is preferable that the double silane coupling agent contains an alkoxysilane containing an amino group, an epoxy group, an acetoacetyl group, a polyalkylene glycol group, an acryl group, Can be used.

The amount of such an additive may be suitably controlled within a range that does not impair the effect of the present invention. For example, the silane coupling agent may be contained in an amount of 0.1 to 2 parts by weight based on 100 parts by weight of the acrylic copolymer in consideration of adhesion strength and durability have.

In particular, the pressure-sensitive adhesive composition of the present invention can be used as a pressure-sensitive adhesive for polarizing plates and a surface protective film for bonding to liquid crystal cells. In addition, it can be used as a general commercial adhesive sheet product as well as a protective film, a reflective sheet, a structural adhesive sheet, a photographic adhesive sheet, a lane marking adhesive sheet, an optical adhesive product, an adhesive for electronic parts, and the like.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Manufacturing example  : Acrylic copolymer preparation

Manufacturing example  A-1: Primary Alcohol groups  Acrylic copolymer

92 parts by weight of n-butyl acrylate (BA), 7 parts by weight of methyl acrylate (MA), 2-hydroxyethyl acrylate 1.0 in a 1 L reactor equipped with a refrigeration system to allow nitrogen gas to reflux and facilitate temperature control. After adding the monomer mixture consisting of parts by weight, 100 parts by weight of acetone was added as a solvent. Then, after purging nitrogen gas for 1 hour to remove oxygen, it was maintained at 55 ℃. After homogenizing the mixture, 0.02 parts by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator, and reacted for 12 hours to have a primary alcohol group having a weight average molecular weight of about 1.5 million. Acrylic copolymer.

Manufacturing example  A-2: Primary Alcohol groups  Acrylic copolymer

The same procedure as in Preparation Example A-1, except that 2-hydroxyethyl acrylate has a primary alcohol group using Formula 4 (wherein R ₁ is hydrogen). Acrylic copolymer.

Manufacturing example  A-3: Primary Alcohol groups  Acrylic copolymer

In the same manner as in Preparation Example A-1, using 4-hydroxybutyl acrylate instead of 2-hydroxyethyl acrylate having a primary alcohol group Acrylic copolymer.

Manufacturing example  A-4: Primary Alcohol groups  Acrylic copolymer

The same procedure as in Preparation Example A-1, except that 2-hydroxyethyl methacrylamide was used instead of 2-hydroxyethyl acrylate to have a primary alcohol group Acrylic copolymer.

Manufacturing example  A-5: 1st Alcohol groups  Acrylic copolymer

In the same manner as in Preparation Example A-1, 92.5 parts by weight of n-butyl acrylate (BA) and 2-instead of 92 parts by weight of n-butyl acrylate (BA) and 1 part by weight of 2-hydroxyethyl acrylate. 0.5 parts by weight of hydroxyethyl acrylate having a primary alcohol group Acrylic copolymer.

Manufacturing example  A-6: Primary Alcohol groups  Acrylic copolymer

In the same manner as in Preparation Example A-1, 90 parts by weight of n-butyl acrylate (BA) and 2-instead of 92 parts by weight of n-butyl acrylate (BA) and 1 part by weight of 2-hydroxyethyl acrylate. Using 3 parts by weight of hydroxyethyl acrylate having a primary alcohol group Acrylic copolymer.

Preparation Example A-7 : Acrylic Copolymer Having a Primary Alcohol Group

In the same manner as in Preparation Example A-1, instead of 92 parts by weight of n-butyl acrylate (BA) and 1 part by weight of 2-hydroxyethyl acrylate 81 parts by weight of n-butyl acrylate (BA) and 2- Using 12 parts by weight of hydroxyethyl acrylate having a primary alcohol group Acrylic copolymer.

Manufacturing example  B-1: 2nd Alcohol groups  Acrylic copolymer

After a nitrogen mixture was refluxed and a monomer mixture consisting of 99.9 parts by weight of n-butyl acrylate (BA) and 0.1 parts by weight of 2-hydroxypropyl acrylate was added to a 1 L reactor equipped with a cooling device. 100 parts by weight of acetone was added as a solvent. Then, after purging nitrogen gas for 1 hour to remove oxygen, it was maintained at 65 ℃. After homogenizing the mixture, 0.1 part by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator, and reacted for 6 hours to have a secondary alcohol group having a weight average molecular weight of about 400,000. Acrylic copolymer.

Manufacturing example  B-2: 2nd Alcohol groups  Acrylic copolymer

The same procedure as in Preparation Example B-1, except that 2-phenoxy-2-hydroxypropyl acrylate was used instead of 2-hydroxyethyl acrylate to have a secondary alcohol group. Acrylic copolymer.

Manufacturing example  B-3: Secondary Alcohol groups  Acrylic copolymer

In the same manner as in Preparation Example B-1, 99.9 parts by weight of n-butyl acrylate (BA) and 99.95 parts by weight of n-butyl acrylate (BA) instead of 0.1 parts by weight of 2-hydroxypropyl acrylate and 2- Using 0.05 parts by weight of hydroxypropyl acrylate having a secondary alcohol group Acrylic copolymer.

Manufacturing example  B-4: 2nd Alcohol groups  Acrylic copolymer

In the same manner as in Preparation Example B-1, 99.9 parts by weight of n-butyl acrylate (BA) and 98 parts by weight of n-butyl acrylate (BA) instead of 0.1 parts by weight of 2-hydroxypropyl acrylate, 2- Using 2 parts by weight of hydroxypropyl acrylate having a secondary alcohol group Acrylic copolymer.

Manufacturing example  B-5: 2nd Alcohol groups  Acrylic copolymer

In the same manner as in Preparation Example B-1, 99.9 parts by weight of n-butyl acrylate (BA) and 95 parts by weight of n-butyl acrylate (BA) instead of 0.1 parts by weight of 2-hydroxypropyl acrylate, 2- Using 5 parts by weight of hydroxypropyl acrylate having a secondary alcohol group Acrylic copolymer.

Manufacturing example  B-6: 2nd Alcohol groups  Acrylic copolymer

In the same manner as in Preparation Example B-1, 99.9 parts by weight of n-butyl acrylate (BA) and 90 parts by weight of n-butyl acrylate (BA) instead of 0.1 parts by weight of 2-hydroxypropyl acrylate, 2- Using 10 parts by weight of hydroxypropyl acrylate having a secondary alcohol group Acrylic copolymer.

Manufacturing example  C-1: Reactivity Functional group  Free Acrylic Copolymer

The same procedure as in Preparation Example B-1, except that 100 parts by weight of n-butyl acrylate (BA) was used to prepare an acrylic copolymer.

Manufacturing example  D-1: acid Functional group  Containing acrylic copolymer

In the same manner as in Preparation Example B-1, an acrylic copolymer was prepared using acrylic acid instead of 2-hydroxypropylacrylate.

Example  1-15 and Comparative Example  1-4

As shown in Table 1 below, an acrylic copolymer having a primary alcohol group, an acrylic copolymer having a secondary alcohol group, a toluene diisocyanate-based (TDI) crosslinking agent, an aliphatic isocyanate-based crosslinking agent and a silane coupling agent (3-glycidoxypropyltrime Toxisilane, KBM-403 manufactured by Shin-Etsu Co., Ltd.) was mixed with 0.5 parts by weight based on 100 parts by weight of the acrylic copolymer, and then diluted in an organic solvent to prepare an adhesive composition.

division
(Parts by weight) Acrylic copolymer Isocyanate system
Cross-linking agent Primary alcohol group (A) Second alcohol group (B) Cor-l Cor-HXR One 2 3 4 5 6 7 One 2 3 4 5 6 Example 1 80 - - - - - - 20 - - - - - 0.8 0.05 Example 2 - 80 - - - - - 20 - - - - - 0.8 0.05 Example 3 - - 80 - - - - 20 - - - - - 0.8 0.05 Example 4 - - - 80 - - - 20 - - - - 0.8 0.05 Example 5 80 - - - - - - - 20 - - - - 0.8 0.05 Example 6 90 - - - - - - 10 - - - - - 0.8 0.05 Example 7 70 - - - - - - 30 - - - - - 0.8 0.05 Example 8 - - - - 80 - - 20 - - - - - 0.5 0.05 Example 9 - - - - - 80 - 20 - - - - - 1.0 0.05 Example 10 - - - - - - 80 20 - - 1.0 0.05 Example 11 80 - - - - - - - - 20 - - - 0.8 0.02 Example 12 80 - - - - - - - - - 20 - - 0.8 0.1 Example 13 80 - - - - - - - - - - 20 - 0.8 0.1 Example 14 80 - - - - - - - - - - - 20 0.8 0.1 Example 15 80 - - - - - - 20 - - - - - 1.5 0.02 Comparative Example 1 100 - - - - - - - - - - - - 1.0 - Comparative Example 2 - - - - - - - 100 - - - - - - 1.0 Comparative Example 3 80 - - - - - - 20 - - - - - 1.0 - Comparative Example 4 80 - - - - - - 20 - - - - - - 1.0 Cor-L: coronate-L (tolylene diisocyanate adduct of trimethylolpropane, product of Nippon Polyurethane Co., Ltd.)
Cor-HXR: Coronate-HXR (HDI isocyanurate, Nippon Polyurethane Co., Ltd. product)
Crosslinking agent is parts by weight based on 100 parts by weight of the acrylic copolymer

Comparative Example  5: conventional SEMI - IPN rescue

In the same manner as in Example 1, but instead of the acrylic copolymer of B-1 to prepare a pressure-sensitive adhesive composition using an acrylic copolymer of C-1.

Comparative Example  6: Acid Polymer  Use

In the same manner as in Example 1, but instead of the acrylic copolymer of B-1 to prepare a pressure-sensitive adhesive composition using an acrylic copolymer of D-1.

Comparative Example  7: Conventional IPN  rescue

10 parts by weight of 1,6-hexanediol diacrylate (HDDA) to a mixture of 100 parts by weight of the acrylic copolymer of A-1 and 1.0 parts by weight of tolylene diisocyanate adduct (TDI-1) of trimethylolpropane and a, a 1 weight part of -methoxy-a-hydroxyacetophenone (Irgacure # -651) was added thereto, followed by stirring to prepare an adhesive composition.

The pressure-sensitive adhesive composition prepared above was applied on a release film coated with a silicone release agent to have a thickness of 25 μm, dried at 100 ° C. for 1 minute, and photocured at 1000 mJ under a fusion lamp to form an adhesive layer.

A pressure-sensitive adhesive polarizing plate was prepared by laminating the pressure-sensitive adhesive layer prepared above on an iodine-based polarizing plate having a thickness of 185 μm. The prepared polarizing plate was stored under curing conditions at 23 ° C. and 60% RH.

Test Example

The physical properties of the pressure-sensitive adhesive composition and pressure-sensitive adhesive polarizing plate prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Table 2 below.

1. Bending

The prepared pressure-sensitive adhesive polarizing plate was bonded to one surface of 17-inch Corning glass and autoclaved. Then, the resultant was heat-treated at 80 ° C. for 100 hours, left at room temperature for 24 hours, and then placed on a flat surface to have a high flatness. The bending characteristic was confirmed by measuring the distance to a side. At this time, when the height is 10 mm or less, it is determined that the bending property is good.

2. Adhesive durability

The release film of the polarizing plate with pressure-sensitive adhesive was peeled off, the surface of the pressure-sensitive adhesive layer was bonded to Corning glass, and after standing at 60 ° C. for 300 hours, the appearance was confirmed (heat resistance test).

<Evaluation Criteria>

Bubbles and peeling phenomenon are observed: x

1-2 bubbles are visually recognized, or less than 1 mm of peeling is visualized: △

Bubbles and Peelings Unidentified: ○

3. Metal layer Corrosion resistance

After the release film of the polarizing plate with the adhesive was peeled off, the surface of the pressure-sensitive adhesive layer was bonded to the aluminum plate, and the sample was allowed to stand for 250 hours in an atmosphere of 60 ° C and 95% RH.

The pressure-sensitive adhesive layer was peeled from the laminate, and the surface of the aluminum plate in contact with the pressure-sensitive adhesive layer was visually observed to evaluate the presence or absence of corrosion.

<Evaluation Criteria>

Aluminum plate surface does not corrode at all: ○

Corrosion of aluminum plate surface: x

division Deflection (/ mm) Adhesive durability Corrosion resistance Example 1 4 ○ ○ Example 2 2 ○ ○ Example 3 3 ○ ○ Example 4 3 ○ ○ Example 5 4 ○ ○ Example 6 6 ○ ○ Example 7 3 ○ ○ Example 8 2 ○ ○ Example 9 7 ○ ○ Example 10 9 △ ○ Example 11 2 ○ ○ Example 12 6 ○ ○ Example 13 8 △ ○ Example 14 9 △ ○ Example 15 3 ○ ○ Comparative Example 1 20 ○ ○ Comparative Example 2 One × ○ Comparative Example 3 14 ○ ○ Comparative Example 4 11 ○ ○ Comparative Example 5 2 × ○ Comparative Example 6 4 ○ × Comparative Example 7 27 ○ ○

As shown in Table 2, the pressure-sensitive adhesive composition of Examples 1 to 15 containing an acrylic copolymer having a primary alcohol group, an acrylic copolymer having a secondary alcohol group, a tolylene diisocyanate crosslinking agent and an aliphatic isocyanate crosslinking agent according to the present invention. Compared with Comparative Examples 1 to 7 it was confirmed that the occurrence of less warpage, excellent durability and satisfactory corrosion protection at the same time.

Claims (8)

The pressure-sensitive adhesive composition containing an acrylic copolymer having a primary alcohol group, an acrylic copolymer having a secondary alcohol group, a tolylene diisocyanate crosslinking agent and an aliphatic isocyanate crosslinking agent.
The pressure-sensitive adhesive composition of claim 1, wherein the acrylic copolymer having a primary alcohol group is copolymerized by containing at least one monomer selected from Chemical Formulas 1 to 5 below:
[Chemical Formula 1]

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 2 to 12)
(2)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 12)
(3)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)
[Chemical Formula 4]

Wherein R ₁ is a hydrogen atom or a methyl group
[Chemical Formula 5]

(Wherein R ₁ is a hydrogen atom or a methyl group).
The pressure-sensitive adhesive composition of claim 2, wherein the acrylic copolymer having a primary alcohol group contains a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and at least one monomer selected from Formulas 1 to 5.
The pressure-sensitive adhesive composition of claim 3, wherein the at least one monomer selected from Formulas 1 to 5 contains 0.1 to 10 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms.
The pressure-sensitive adhesive composition of claim 1, wherein the acrylic copolymer having a secondary alcohol group is copolymerized by containing at least one monomer selected from Chemical Formulas 6 to 9.
[Chemical Formula 6]

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)
(7)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)
[Chemical Formula 8]

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)
[Chemical Formula 9]

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)
The pressure-sensitive adhesive composition of claim 5, wherein the acrylic copolymer having a secondary alcohol group contains a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and at least one monomer selected from Formulas 6 to 9.
The pressure-sensitive adhesive composition of claim 6, wherein the at least one monomer selected from Formulas 6 to 9 contains 0.01 to 5 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms.
According to claim 1, 60 to 95 parts by weight of the acrylic copolymer having a primary alcohol group, 5 to 40 parts by weight of the acrylic copolymer having a secondary alcohol group, 0.1 to 5 parts by weight of toluene diisocyanate-based crosslinking agent and aliphatic isocyanate Adhesive composition containing 0.01-1 weight part of crosslinking agents.