Photocurable adhesive composition
Provided is an adhesive composition comprising: a thermosetting epoxy resin formed with an epoxy copolymer containing a hydroxyl group; and a UV curable epoxy resin having an epoxy equivalence of 100 g/eq to 500 g/eq.
1. An adhesive composition comprising: a thermally curable epoxy resin formed of a hydroxyl group-containing epoxy copolymer; and a UV curable epoxy resin having an epoxy equivalent weight of 100 g/eq to 500 g/eq, wherein
the epoxy copolymer has a weight average molecular weight of 20,000 to 70,000; and
the thermally curable epoxy resin has a hydroxyl group equivalent weight of 200 g/eq to 400 g/eq.
2. The adhesive composition according to claim 1 , wherein the epoxy copolymer has a structure in which the hydroxyl group is substituted into a main chain thereof.
3. The adhesive composition according to claim 1 , wherein the epoxy copolymer has a glass transition temperature of 50° C. to 90° C.
4. The adhesive composition according to claim 1 , wherein the UV curable epoxy resin comprises a novolac type epoxy resin.
5. The adhesive composition according to claim 4 , wherein the novolac type epoxy resin comprises any one selected from the group consisting of phenol novolac type, cresol novolac type, cycloaliphatic novolac type, cycloaliphatic novolac type modified, bisphenol novolac type, biphenyl novolac type, naphthol novolac type epoxy resins, and combinations thereof.
6. The adhesive composition according to claim 1 , wherein the UV curable epoxy resin has a glass transition temperature of 60° C. to 90° C.
7. The adhesive composition according to claim 1 , wherein the thermally curable epoxy resin is present in an amount of 10 parts by weight to 60 parts by weight based on 100 parts by weight of the UV curable epoxy resin.
8. The adhesive composition according to claim 1 , further comprising: a cationic photoinitiator.
9. The adhesive composition according to claim 8 , wherein the cationic photoinitiator is present in an amount of 5 parts by weight to 15 parts by weight based on 100 parts by weight of the UV curable epoxy resin.
10. The adhesive composition according to claim 1 , wherein the adhesive composition has a difference in surface energy of 2 dyne/cm to 4 dyne/cm between before and after photocuring.
11. The adhesive composition according to claim 1 , wherein the adhesive composition has a difference in contact angle of 5° C. to 20° C. between before and after photocuring.