Adhesive Composition

Abstract

An adhesive composition includes a polyvinyl alcohol binder, a crosslinking agent and a compound of Formula 1 below,

HOSO.sub.2R[Formula 1] wherein in Formula 1, R is an alkyl group, a haloalkyl group or a haloalkylaryl group. The adhesive composition may have excellent water resistance, adhesive force and other optical properties as well as greatly improved storage stability.

Claims

1. An adhesive composition comprising: a polyvinyl alcohol binder; a crosslinking agent; and a compound of Formula 1 below:
HOSO.sub.2R[Formula 1] wherein in Formula 1, R is an alkyl group, a haloalkyl group or a haloalkylaryl group.

2. The adhesive composition according to claim 1, wherein the polyvinyl alcohol binder is an aqueous binder.

3. The adhesive composition according to claim 1, wherein the polyvinyl alcohol binder includes an acetoacetyl group.

4. The adhesive composition according to claim 1, wherein the crosslinking agent is a melamine crosslinking agent.

5. The adhesive composition according to claim 1, wherein the crosslinking agent is represented by Formula 2 below: ##STR00003## wherein in Formula 2, each R is independently a hydrogen atom, a hydroxyalkyl group, an alkoxyalkyl group, an alkoxy group or a carboxyalkyloxyalkyl group.

6. The adhesive composition according to claim 1, wherein the crosslinking agent is in a ratio of 5 to 50 parts by weight relative to 100 parts by weight of the binder.

7. The adhesive composition according to claim 1, wherein in Formula 1, R is a haloalkyl group or a haloalkylaryl group.

8. The adhesive composition according to claim 1, wherein in Formula 1, R is a perfluoroalkyl group or a perfluoroalkylaryl group.

9. The adhesive composition according to claim 1, wherein the compound of Formula 1 is in a ratio of 0.1 to 20 parts by weight relative to 100 parts by weight of the binder.

10. The adhesive composition according to claim 1, further comprising a silane compound.

11. The adhesive composition according to claim 10, wherein the silane compound is represented by Formula 3 below:
R.sup.1.sub.nSiR.sup.2.sub.(4-n)[Formula 3] wherein in Formula 3, R.sup.1 is a glycidoxyalkyl group, a (meth)acryloyloxyalkyl group or an aminoalkyl group, R.sup.2 is a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, n is a number in a range of 1 to 4, and if R.sup.1 and R.sup.2 are each plural, they are each the same or different.

12. The adhesive composition according to claim 10, wherein the silane compound is in a ratio of 1 to 100 parts by weight relative to 100 parts by weight of the binder.

13. An optical laminate comprising: a first optical film; a second optical film; and an adhesive layer of the adhesive composition of claim 1, wherein the adhesive layer attaches the first optical film and the second optical film to each other.

14. The optical laminate according to claim 13, wherein the first optical film or the second optical film is a polarizer and the other is a protective film.

15. A display device comprising the optical laminate of claim 13.

Description

MODE FOR INVENTION

[0092] Hereinafter, the adhesive composition of the present application will be specifically described through Examples and Comparative Examples, but the scope of the present application is not limited by the following examples.

[0093] 1. Storage Stability Evaluation

[0094] The storage stability of the adhesive composition was evaluated by confirming the time maintained without occurrence of gelation. It was confirmed by leaving each of adhesive compositions of Examples or Comparative Examples at room temperature and evaluating the viscosity at the same time every day whether or not gelation occurred in the adhesive composition, where the time point at which the flowability of the water-based composition disappeared was evaluated as occurrence of gelation.

[0095] The results were summarized in Table 1 below.

[0096] 2. Evaluation of High Temperature and Room Temperature Water Resistance

[0097] In the evaluation of high temperature water resistance, a film coated with an adhesive composition was placed in a thermostatic bath at 60 C. and the time point at which the coated adhesive composition was dissolved was evaluated, where the case that the dissolution was not observed was indicated by P in Table 1 below. Also, the room temperature water resistance was evaluated in a thermostatic bath at room temperature in the same manner.

Example 1

[0098] As the binder, an acetoacetyl group-modified polyvinyl alcohol resin (Z-200, Nippon Synthetic Chemical Gohasefimer, Co.) was used, and methylol melamine (in Formula 2 below, a compound in which all R's are each a hydroxymethyl group) as a crosslinking agent, 3-glycidoxypropyltrimethoxysilane as a silane compound and a compound of Formula 1 were mixed with the resin to prepare an adhesive composition. Here, as the compound of Formula 1, a compound wherein R in Formula 1 below is a trifluoromethyl group in Formula 1) was used.

[0099] The binder, the crosslinking agent, the silane compound and the compound of Formula 1 were mixed in a solvent (deionized water) in a weight ratio of 100:15:10:2 (binder:crosslinking agent:silane compound:composition of Formula 1) to prepare an adhesive composition.

HOSO.sub.2R[Formula 1]

##STR00002##

Example 2

[0100] As the compound of Formula 1, a compound, wherein R in Formula 1 above is a methyl group, was used and the binder, the crosslinking agent, the silane compound and the compound of Formula 1 were mixed in deionized water as a solvent in a weight ratio of 100:15:10:2 (binder:crosslinking agent:silane compound:compound of Formula 1) to prepare an adhesive composition.

Example 3

[0101] As the compound of Formula 1, a compound, wherein R in Formula 1 above is a methyl group, was used and the binder, the crosslinking agent, the silane compound and the compound of Formula 1 were mixed in deionized water as a solvent in a weight ratio of 100:15:10:10 (binder:crosslinking agent:silane compound:compound of Formula 1) to prepare an adhesive composition.

Comparative Example 1

[0102] Only a binder (Z-200, Nippon Synthetic Chemical Gohasefimer, Co.) was dispersed in deionized water as a solvent to prepare an adhesive composition.

Comparative Example 2

[0103] Only the binder and crosslinking agent of Example 1 were dispersed in deionized water as a solvent in a weight ratio of 100:15 (binder:crosslinking agent) to prepare an adhesive composition.

Comparative Example 3

[0104] Only the binder, crosslinking agent and silane compound of Example 1 were dispersed in deionized water as a solvent in a weight ratio of 100:15:10 (binder:crosslinking agent:silane compound) to prepare an adhesive composition.

Comparative Example 4

[0105] The binder, crosslinking agent, silane compound and acetic acid of Example 1 were dispersed in deionized water as a solvent in a weight ratio of 100:15:10:10 (binder:crosslinking agent:silane compound:acetic acid) to prepare an adhesive composition.

[0106] The physical properties confirmed for Examples and Comparative Examples above were summarized and described in Table 1 below.

TABLE-US-00001 TABLE 1 High temperature Room temperature Storage stability water resistance water resistance Example 1 21 days P P 2 21 days P P 3 21 days P P Comparative 1 21 days Total dissolution Total dissolution Example 2 Less than 1 day 50% or more 50% or more dissolution dissolution 3 Less than 1 day Partial dissolution Partial dissolution 4 Less than 5 days Partial dissolution Partial dissolution

[0107] From the results of Table 1, it can be confirmed that through comparison of Comparative Examples 1 to 3, the polyvinyl alcohol binder alone ensures storage stability, but the water resistance is deteriorated, whereas in the case of mixing the crosslinking agent or the silane compound, the water resistance is improved to some extent, but the storage stability is deteriorated. Also, when the acetic acid is mixed, the storage stability is improved to some extent, but the degree of improvement is insufficient and the water resistance is still insufficient.

[0108] Accordingly, it can be confirmed that when the compound of Formula 1 according to the present application is mixed, the water resistance and the storage stability are simultaneously improved. Although this is not clear, it is presumed that the compound of Formula 1 is capping the crosslinking agent to increase the storage stability and then is decapping it sufficiently quickly.