Dual curing adhesive

Abstract

A dual-curing adhesive comprises multifunctional epoxy resin, thermal curing agent, photoinitiator, and a compound having an epoxy group and a radically-polymerisable group. The compound may be presen

Claims

1. A dual-curing adhesive for manufacturing an electronic device, the dual-curing adhesive comprising:a compound comprising at least one epoxy group and at least one radically polymerizable group,a multifunctional epoxy resin,a thermal curing agent, and a photoinitiator.

2. The dual-curing adhesive according to claim 1, wherein the at least one radically polymerizable group comprises acylate and / or methacrylate.

3. The dual-curing adhesive according to claim 1 or claim 2, wherein the compound comprising at least one epoxy group and at least one radically polymerizable group comprises a bisphenol group, preferably a bisphenol A group a bisphenol E group and / or a bisphenol F group, more preferably a bisphenol A group.

4. The dual-curing adhesive according to any preceding claim, wherein the compound comprising at least one epoxy group and at least one radically polymerizable group comprises:

5. The dual-curing adhesive according to any preceding claim, comprising from 5 to 50 wt.% of the compound comprising at least one epoxy group and at least one radically polymerizable group, based on the total weight of the dual-curing adhesive, preferably from 5 to 20 wt.%, more preferably from 9 to 16 wt.%.

6. The dual-curing adhesive according to any preceding claim, wherein the multifunctional epoxy resin comprises bifunctional epoxy resin.

7. The dual-curing adhesive according to any preceding claim, wherein the multifunctional epoxy resin comprises a bisphenol-based epoxy resin, preferably a bisphenol A-based epoxy resin and / or bisphenol E-based epoxy resin and / or a bisphenol F-based epoxy resin, more preferably a bisphenol A-based epoxy resin and bisphenol E-based epoxy resin.

8. The dual-curing adhesive according to any preceding claim, comprising from 5 to 50 wt.% of the multifunctional epoxy resin, based on the total weight of the dual-curing adhesive, preferably from 10 to 35 wt.%, more preferably from 13 to 30 wt.%.

9. The dual-curing adhesive according to any preceding claim, wherein the multifunctional epoxy resin comprises one or more of bisphenol A diglycidyl ether, bisphenol E diglycidyl ether, and 1,4-cyclohexanedimethanol diglycidyl ether, preferably two or more.

10. The dual-curing adhesive according to claim 9, comprising, based on the total weight of the dual-curing adhesive:from 1 to 15 wt.% of the bisphenol A diglycidyl ether, preferably from 7 to 13 wt.%, more preferably from 9 to 12 wt.%; and / orfrom 1 to 15 wt.% of the bisphenol E diglycidyl ether, preferably from 7 to 13 wt.%, more preferably from 9 to 12 wt.%; and / orfrom 1 to 10 wt.% of the 1,4-cyclohexanedimethanol diglycidyl ether, preferably from 3 to 7 wt.%, more preferably from 4 to 6 wt.%.

11. The dual-curing adhesive according to any preceding claim, wherein the thermal curing agent comprises nitrogen, preferably wherein the thermal curing agent comprises amine or imidazole, more preferably amine, even more preferably primary amine.

12. The dual-curing adhesive according to claim 11, wherein the amine has an amine value of from 100 to 170, preferably from 110 to 160, more preferably from 110 to 120 or from 140 to 160.

13. The dual-curing adhesive according to any preceding claim, comprising from 1 to 20 wt.% of the thermal curing agent, based on the total weight of the dual-curing adhesive, preferably from 2 to 10 wt.%, more preferably from 3 to 7 wt.%.

14. The dual-curing adhesive according to any preceding claim, wherein: the photoinitiator is a UV photoinitiator, preferably wherein the photoinitiator absorbs light having a wavelength of from 325 to 425 nm, more preferably from 345 to 410 nm, even more preferably from 365 to 400 nm; and / orthe photoinitiator comprises one or both of: phenyl bis (2,4,6-trimethyl benzoyl) phosphine oxide and benzil dimethyl ketal, preferably both.

15. The dual-curing adhesive according to any preceding claim, comprising from 0.5 to 5 wt.% of the photoinitiator, based on the total weight of the dual-curing adhesive, preferably from 1 to 4 wt.%.

16. The dual-curing adhesive according to any preceding claim, wherein the dualcuring adhesive further comprises one or more additives selected from:a hardener, preferably a thiol-based hardener, more preferably comprising one or both of 2,2-bis{[(3-sulfanylpropanoyl)oxy]methyl}butyl 3-sulfanylpropanoate and pentaerythritol tetrakis (3-mercaptobutylate);a reactive diluent, preferably comprising a trifunctional acrylic monomer or a diacrylate monomer, more preferably comprising one or both of trimethylolpropane triacrylate (TMPTA) monomer and tricyclodecane dimethanol diacrylate (TCDDMDA) monomer;an inorganic filler, preferably comprising one or both of silica and fumed silica;a toughening agent, preferably comprising core-shell rubber;a stabilizer, preferably comprising organic acid; and carbon black.

17. The dual-curing adhesive according to claim 16, wherein the dual-curing adhesive comprises from 30 to 80 wt.% in total of the one or more additives, based on the total weight of the dual-curing adhesive, preferably grom 50 to 75 wt.%, more preferably from 55 to 70 wt.%.

18. The dual-curing adhesive according to claim 16 or claim 17, wherein the dualcuring adhesive comprises, based on the total weight of the dual-curing adhesive:from 10 to 35 wt.% of the hardener, preferably from 20 to 30 wt.%, more preferably from 22 to 28 wt.%; and / orfrom 1 to 15 wt.% of the reactive diluent, preferably from 4 to 12 wt.%; and / or from 15 to 30 wt.% of the inorganic filler, preferably from 17 to 28 wt.%; and / or from 1 to 6 wt.% of the toughening agent, preferably from 3 to 5 wt.%; and / or from 0.1 to 1 wt.% of the stabilizer, preferably from 0.4 to 0.7 wt.%; and / or from 0.001 to 0.1 wt.% of carbon black, preferably from 0.005 to 0.05, more preferably from 0.01 to 0.03 wt.%.

19. The dual-curing adhesive according to any preceding claim, wherein: the dual-curing adhesive is solvent-free; and / or the electronic device comprises a digital camera.

20. The dual-curing adhesive according to any preceding claim, wherein the dualcuring adhesive exhibits:a viscosity of from 30,000 cP to 55,000 cP; and / ora thixotropic index of from 4 to 8.

21. A method of forming a joint between two or more work pieces to be joined, the method comprising:disposing the dual-curing adhesive of any preceding claim in the vicinity of two or more work pieces to be joined;exposing at least some of the dual-curing adhesive to actinic radiation in air;heating the dual-curing adhesive to a temperature of from 40 to 90 °C for a period of time of from 10 to 150 minutes.

22. A method of manufacturing the dual-curing adhesive of any of claims 1 to 20, the method comprising:providing a first mixture of photoinitiator and a compound comprising at least one epoxy group and at least one radically polymerizable group;providing a second mixture of a multifunctional epoxy resin and a thermal curing agent; andcombining the first mixture and the second mixture.

23. An electronic device manufactured using the adhesive of any of claims 1 to 20.

24. An electronic device comprising the adhesive of any of claims 1 to 20 in cured5 form.

25. The electronic device of claim 23 or claim 24, wherein the electronic devicecomprises a digital camera.25

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