Curable composition

Abstract

The present application relates to a curable composition. The curable composition of the present application exhibits excellent adhesion ability and liquid crystal orientation ability simultaneously before or after curing, so that it can be effectively applied to various optical uses.

Claims

1. A curable composition comprising an epoxy compound; a bisphenol type phenoxy resin; and a bisphenol type (meth)acrylate in a ratio of 60 parts by weight or less relative to 100 parts by weight of the epoxy compound, wherein the epoxy compound comprises a bisphenol type epoxy resin having an epoxy equivalent weight of 350 g/eq or more, and a bisphenol type epoxy resin having an epoxy equivalent weight of 300 g/eq or less, and the bisphenol type epoxy compound having an epoxy equivalent weight of 300 g/eq or less is comprised in a ratio of 40 to 80 parts by weight relative to 100 parts by weight of the bisphenol type epoxy resin having an epoxy equivalent weight of 350 g/eq or more.

2. The curable composition according to claim 1, wherein the bisphenol type (meth)acrylate is a compound having a bisphenol framework to which at least one (meth)acrylic functional group is linked.

3. The curable composition according to claim 1, wherein the bisphenol type (meth)acrylate is represented by Formula 1 below: ##STR00002## wherein, L is an alkylene group or alkylidene group having 1 to 8 carbon atoms, and R.sub.1 to R.sub.10 are each independently hydrogen, halogen, an alkyl group, an alkoxy group, a cyano group, a nitro group, —(O-A).sub.n-R, -(A-O).sub.n—R, —(O-A-O).sub.n—R, a (meth)acryloyl group, a (meth)acryloyloxy group, a (meth)acryloyloxyalkyl group or a (meth)acryloyloxyalkyloxy group, where A is an alkylene group, R is a (meth)acryloyl group or a (meth)acryloyloxy group, n is a number in a range of 1 to 10, and at least one of R.sub.1 to R.sub.10 is —(O-A).sub.n-R, -(A-O).sub.n—R, —(O-A-O).sub.n—R, a (meth)acryloyl group, a (meth)acryloyloxy group, a (meth)acryloyloxyalkyl group or a (meth)acryloyloxyalkyloxy group.

4. The curable composition of claim 1, wherein the bisphenol type phenoxy resin has a weight average molecular weight in a range of 30,000 to 150,000 g/mol.

5. The curable composition according to claim 1, further comprising a cationic initiator.

6. The curable composition of claim 1, further comprising a radical initiator.

7. The curable composition according to claim 1, wherein the epoxy compound is present in the curable composition in a ratio of 10 wt % to 90 wt %.

8. A method for preparing a liquid crystal orientational adhesive layer comprising steps of: coating a layer with the curable composition of claim 1; performing an orientation treatment on the layer; curing the layer on which the orientation treatment has been performed; and heat treating the layer after the curing treatment.

9. The method for preparing a liquid crystal orientational adhesive layer according to claim 8, wherein the heat treatment is performed at a temperature in a range of 50° C. to 100° C.

10. The method for preparing a liquid crystal orientational adhesive layer according to claim 8, wherein the heat treatment is performed for 10 minutes to 60 minutes.

11. An optical device comprising first and second substrates disposed opposite to each other; a liquid crystal layer existing between the first and second substrates; and a cured layer coated with the curable composition of claim 1 on a surface of the second substrate, which faces the liquid crystal layer.

12. The optical device according to claim 11, wherein a lens layer is present on a surface of the first substrate, which faces the liquid crystal layer.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The FIGURE is an exemplary unit structure of an auto-stereoscopic 3D display device, which is one example to which the curable composition of the present application can be applied.

ADVANTAGEOUS EFFECTS

(2) The present application relates to a curable composition. The curable composition of the present application exhibits excellent adhesion ability and liquid crystal orientation ability simultaneously before or after curing, so that it can be effectively applied to various optical uses.

MODE FOR INVENTION

(3) Hereinafter, the present application will be described in detail with reference to Examples according to the present application and Comparative Examples not complying with the present application, but the scope of the present application is not limited to the following examples.

(4) 1. Rubbing Processability Evaluation

(5) The curable compositions prepared in Examples and Comparative Examples are each coated on an ITO layer of a general ITO film (a film in which ITO (indium tin oxide) is deposited on one side of a PET (poly(ethylene terephthalate)) film) (the substrate (200) of the FIGURE) to a thickness of about 10 μm, dried at a temperature of about 130° C. for about 3 minutes, and then rubbed with a rubbing cloth applied to a normal rubbing orientation. Thereafter, the substrate on which the lens structure is formed (the substrate (100) of the FIGURE on which the lens layer (300) is formed) is attached to the cured layer subjected to the rubbing orientation after the heat treatment, irradiated with ultraviolet rays of about 3 J/cm2 by a metal halide lamp and the liquid crystals are injected into the space (500 in the FIGURE) therebetween, and then it is confirmed whether the liquid crystal orientation has been well formed using a polarizing microscope (Nikon Corporation, ECLIPSE E600WPOL). When the liquid crystal orientation was formed, it was evaluated as P, and when the orientation was not formed or the orientation defect was observed, it was evaluated as NG.

(6) 2. Liquid Crystal Orientation Evaluation

(7) The sample applied at the time of evaluating the rubbing orientation is further aged at a temperature of about 50° C. to 100° C. for about 10 minutes to 1 hour, and then it is confirmed whether the liquid crystal orientation has been well formed using a polarizing microscope (Nikon Corporation, ECLIPSE E600WPOL), as in the rubbing processability evaluation. When the liquid crystal orientation was formed, it was evaluated as P, and when the orientation was not formed or the orientation defect was observed, it was evaluated as NG.

(8) 3. Lens Attachment Property

(9) The sample applied at the time of evaluating the liquid crystal orientation was bent and unbent, and then the attachment degree of the layer of the curable composition to the lens and the ITO layer was observed, and when there was no abnormality, it was evaluated as P and when the attachment was detached or the defects of the liquid crystal orientation was observed, it was evaluated as NG.

(10) 4. ITO Adhesion

(11) The curable compositions prepared in Examples or Comparative Examples were each coated on the ITO layer of the ITO film, irradiated with ultraviolet rays and aged in the same manner as in the rubbing processability evaluation and the liquid crystal orientation evaluation, and subjected to a cross cut test according to ASTM D3359 standard, and when the cured layer was not detached at all, it was evaluated as P and when it was partly or entirely detached, it was evaluated as NG.

Example 1

(12) Epiclon 1055 (bisphenol A type epoxy compound, epoxy equivalent weight: 450 to 500 g/eq; softening point: 64° C. to 74° C.) from DIC Corporation as a solid epoxy compound, YD-128 (liquid bisphenol A type epoxy compound, epoxy equivalent weight: 184 to 190 g/eq) from Kukdo Chemical Co., Ltd. as a liquid epoxy compound, CN110NS (bisphenol A type epoxy acrylate, liquid phase) from Sartomer as a bisphenol type (meth)acrylate, YP-50 (bisphenol A type phenoxy resin, molecular weight: 60,000 to 80,000 g/mol) as a phenoxy resin, Irgacure 184 from BASF as a photo radical initiator and CPI-101A from SAN-APRO as a photo cationic initiator were introduced into a reactor in a weight ratio of about 15:10:15:58:1:1 (Epiclon 1055:YD-128:CN110NS:YP-50:Irgacure 184:CPI-101A), diluted appropriately with methyl ethyl ketone, and then the inside of the reactor was replaced with nitrogen and homogenized to prepare a curable composition. In the case of the curable composition of Example 1, the heat treating (aging) temperature at the time of evaluating physical properties was about 50° C., and the time was about 1 hour.

Examples 2 to 7 and Comparative Examples 1 to 3

(13) A curable composition was prepared in the same manner as in Example 1, except that the kinds and ratios of the components used were changed as shown in Table 1 below.

(14) TABLE-US-00001 TABLE 1 Example Comparative Example 1 2 3 4 5 6 7 1 2 3 Epoxy Epiclon 1055 15 25 25 25 25 25 25 25 25 15 compound YD-128 10 10 20 10 10 10 10 15 20 10 (Meth)acrylate CN110NS 15 15 13 15 15 15 15 25 Phenoxy resin YP-50 58 48 48 48 48 48 58 53 48 YP-70 40 Radical initiator Irgacure 184 1 1 1 1 1 1 1 1 1 Cationic initiator CPI-101A 1 1 1 1 1 1 1 1 1 Curing agent C11ZA 2 Heat treatment Temperature (° C.) 50 50 50 50 80 100 100 50 50 50 Time (minute) 60 50 60 60 60 10 60 60 60 60 Content unit: part by weight Epiclon 1055: bisphenol A type epoxy compound, epoxy equivalent weight: 450 to 500 g/eq, softening point: 64° C. to 74° C. (DIC Corporation) YD-128: liquid bisphenol A type epoxy compound, epoxy equivalent weight: 184 to 190 g/eq, Kukdo Chemical Co., Ltd. CN110NS: bisphenol A type epoxy acrylate, liquid phase, Sartomer product YP-50: bisphenol A type phenoxy resin, molecular weight: 60,000 to 80,000 g/mol YP-70 bisphenol A type phenoxy resin, molecular weight: 50,000 to 60,000 g/mol Irgacure 184: radical initiator(BASF) CPI-101A: cationic initiator (SAN-APRO product, liquid phase) C11ZA: heat curing agent (Shikoku Chemicals Corporation)

(15) The measured evaluation results of Examples and Comparative Examples above are as shown in Table 2 below.

(16) TABLE-US-00002 TABLE 2 Comparative Example Example 1 2 3 4 5 6 7 1 2 3 Rubbing P P P P P P P P P NG processability Liquid crystal P P P P P P P NG P NG orientation Lens attachment P P P P P P P P NG P property (before ultraviolet irradiation) Lens attachment P P P P P P P P NG NG property (after ultraviolet irradiation) ITO adhesion P P P P P P P P P P

EXPLANATION OF REFERENCE NUMERALS

(17) 100, 200: substrate 300: lens structure 400: alignment layer, cured layer of curable composition 500: inner space