Photocurable adhesive composition and display device comprising same

Patent metadata

Field	Value
Publication number	US-9175196-B2
Application number	US-201214362502-A
Country	US
Kind code	B2
Filing date	Aug 6, 2012
Priority date	Dec 7, 2011
Publication date	Nov 3, 2015
Grant date	Nov 3, 2015

Abstract

The present invention relates to a photocurable adhesive composition. The photocurable adhesive composition comprises a urethane(meth)acrylate resin, a functional-group-containing polybutadiene, a photocurable monomer and a photoinitiator; and the functional group is either an epoxy group or a hydroxyl group. The photocurable adhesive composition ensures good outdoor readability, has outstanding adhesive properties, and impact strength and optical transparency, and minimizes the phenomenon whereby substantial contraction occurs during photocuring, and thus can be suitably used for a display.

First claim

The invention claimed is:

1. A photocurable adhesive composition comprising a urethane (meth)acrylate resin, a functional group-containing polybutadiene, a photocurable monomer, and a photoinitiator, wherein:
the functional group is an epoxy group or a hydroxyl group,
the composition has a pH of more than 4, and
the urethane (meth)acrylate resin is free from a hydroxyl group.

2. The photocurable adhesive composition according to claim 1 , wherein the photocurable adhesive composition provides a curing contraction rate of about 3.5% or less and an elongation of about 200% to about 800% in accordance with ASTM D638.

3. The photocurable adhesive composition according to claim 1 , wherein the urethane (meth)acrylate resin and the functional group-containing polybutadiene are present in a combined amount of about 50 wt % to about 80 wt % based on a total weight of the adhesive composition.

4. The photocurable adhesive composition according to claim 1 , wherein each of the urethane (meth)acrylate resin and the functional group-containing polybutadiene contains a terminal vinyl group.

5. The photocurable adhesive composition according to claim 1 , comprising: about 25 wt % to about 76 wt % of the urethane (meth)acrylate resin, about 2.5 to about 40 wt % of the functional group-containing polybutadiene, about 15 wt % to about 40 wt % of the photocurable monomer, and about 1 wt % to about 5 wt % of the photoinitiator.

6. The photocurable adhesive composition according to claim 1 , wherein the urethane (meth)acrylate resin and the functional group-containing polybutadiene are present in a urethane (meth)acrylate resin:functional group-containing polybutadiene weight ratio of about 1:1 to about 20:1.

7. The photocurable adhesive composition according to claim 1 , wherein the urethane (meth)acrylate resin has a weight average molecular weight of about 3,000 g/mol to about 25,000 g/mol and a polydispersity index of about 1 to about 3.

8. The photocurable adhesive composition according to claim 1 , wherein the urethane (meth)acrylate resin has a glass transition temperature of about −65° C. to about −55° C. and a viscosity at 25° C. of about 5,000 cPs to about 45,000 cPs.

9. The photocurable adhesive composition according to claim 1 , wherein the photocurable adhesive composition provides a storage modulus of about 10 kPa to about 100 kPa.

10. The photocurable adhesive composition according to claim 1 , wherein the functional group-containing polybutadiene is an epoxy group-containing polybutadiene.

11. The photocurable adhesive composition according to claim 10 , wherein the epoxy group-containing polybutadiene has a number average molecular weight of about 3,000 g/mol to about 20,000 g/mol and a viscosity at 45° C. of about 20,000 cPs to about 120,000 cPs.

12. The photocurable adhesive composition according to claim 10 , wherein the epoxy group-containing polybutadiene has an epoxy equivalent weight of about 100 g/eq. to about 500 g/eq.

13. The photocurable adhesive composition according to claim 10 , wherein the epoxy group-containing polybutadiene has a glass transition temperature of about −70° C. to about −30° C.

14. The photocurable adhesive composition according to claim 11 , wherein the epoxy group-containing polybutadiene has a repeat unit represented by one or more of Formula 1-1 to Formula 1-4:

15. The photocurable adhesive composition according to claim 1 , wherein the functional group-containing polybutadiene is a hydroxyl group-containing polybutadiene.

16. The photocurable adhesive composition according to claim 15 , wherein the hydroxyl group-containing polybutadiene has a weight average molecular weight of about 1,500 g/mol to about 10,000 g/mol and a polydispersity index of about 1.2 to about 2.7.

17. The photocurable adhesive composition according to claim 15 , wherein the hydroxyl group-containing polybutadiene has a hydroxy value of about 0.7 meq/g to about 1.9 meq/g and a butadiene group content of 70% or more.

18. The photocurable adhesive composition according to claim 15 , wherein the hydroxyl group-containing polybutadiene has a glass transition temperature of about −80° C. to about −70° C.

19. The photocurable adhesive composition according to claim 15 , wherein the hydroxyl group-containing polybutadiene has a structure represented by Formula 2:

(where x ranges from about 0.1 to about 0.35, y ranges from about 0.1 to about 0.35, and z ranges from about 0.4 to about 0.7).

20. The photocurable adhesive composition according to claim 1 , wherein the photocurable monomer comprises at least one selected from the group consisting of a hydroxyl group-containing (meth)acrylate, a monocyclic or heterocyclic aliphatic ring-containing (meth)acrylate, a (meth)acrylic monomer having a monocyclic aliphatic hetero-ring including nitrogen, oxygen or sulfur, a carboxyl group-containing (meth)acrylic monomer, and a vinyl group and silane group-containing monomer.

21. The photocurable adhesive composition according to claim 1 , further comprising: one or more of a silane coupling agent, a UV absorbent, or a heat stabilizer.

22. A display comprising the photocurable adhesive composition according to claim 1 .

23. The display according to claim 22 , wherein the photocurable adhesive composition forms an adhesive film interposed between and in contact with a cover window and an ITO substrate.

Assignees

• Ha Kyoung Jin
• Kwon Ji Hye
• Kim Lee June
• Nam Irina
• Oh Se Il
• Choi Seung Jib
• Cheil Ind Inc

Inventors

• Ha Kyoung Jin
• Kwon Ji Hye
• Kim Lee June
• Nam Irina
• Oh Se Il
• Choi Seung Jib

Classifications

• C09J133/066 Primary

  containing -OH groups · CPC title

• C09J4/00

  Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond {; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16} · CPC title

• G02F2201/503

  Arrangements improving the resistance to shock · CPC title

• G02F2201/54

  Arrangements for reducing warping-twist · CPC title

• G02F2202/28

  Adhesive materials or arrangements · CPC title