REACTIVE FILM ADHESIVE

• US 20140158296A1
• Filed: 12/11/2013
• Published: 06/12/2014
• Est. Priority Date: 12/11/2012
• Status: Active Grant

• Current Assignee: Adhesives Research Inc.
• Original Assignee: Adhesives Research Inc.
• Inventors: WIGDORSKI, Robert M., HERR, Donald
• Granted Patent: US 9,512,340 B2
• Time in Patent Office: Days
• US Class Current: 156/307.1
• CPC Class Codes: C08G 59/687 containing sulfur
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: C08L 63/00 Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• CPC Class Codes: C08L 67/00 Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain of polyester-amides C08L77/12; of polyester-imides C08L79/08; Compositions of derivatives of such polymers
• CPC Class Codes: C09J 163/00 Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
• CPC Class Codes: C09J 167/00 Adhesives based on polyesters obtained by reactions forming a carboxylic ester link in the main chain based on polyester-amides C09J177/12; based on polyester-imides C09J179/08; Adhesives based on derivatives of such polymers
• CPC Class Codes: C09J 2463/00 Presence of epoxy resin
• CPC Class Codes: C09J 2467/00 Presence of polyester
• CPC Class Codes: C09J 7/10 without carriers
• CPC Class Codes: C09J 7/20 characterised by their carriers
• CPC Class Codes: C09J 7/30 characterised by the adhesive composition

Abstract

An actinic radiation activated, thermally curable solid film adhesive is disclosed that includes a film forming polymeric binder, a cationically curable resin, and a cationic photoinitiator. The solid film adhesive is capable of being processed at temperatures up to 120° C. prior to exposure to actinic radiation without curing, has a latency period at room temperature following activation of the initiator, and is curable at temperatures above 50° C. following activation of the initiator.

Claims

1. An actinic radiation activated, thermally curable solid film adhesive comprising a film forming polymeric binder, a cationically curable resin, and a cationic photoinitiator, wherein the solid film adhesive is processable at temperatures up to 120°

C. prior to exposure to actinic radiation without curing, has a latency period at room temperature following activation of the initiator, and is curable at temperatures above 50°

C. following activation of the initiator.

2. The solid film adhesive of claim 1 wherein the film forming polymeric binder is selected from the group consisting of a polyester, a polyurethane, styrene-butadiene rubber, nitrile rubber, carboxy-terminal nitrile rubber, poly(butadiene) rubber, poly(isoprene) rubber, styrene block copolymer, poly(isobutylene), an acrylic polymer, a polyamide, a polyimide, a siloxane polyimide, and combinations thereof and wherein the cationically curable resin is a solid multifunctional epoxy resin.

3. The solid film adhesive of claim 2 wherein the film forming polymeric binder is a polyester.

4. The solid film adhesive of claim 1 further comprising a liquid additive present in an amount of less than 30% by weight of the film forming polymeric binder.

5. The solid film adhesive of claim 4, wherein the additive is a polyol or epoxy resin.

6. The solid film adhesive of claim 1, wherein the cationic photoinitiator is UV activated.

7. The solid film adhesive of claim 6, wherein the cationic photoinitiator comprises a triarylsulfonium salt.

8. The solid film adhesive of claim 6, wherein the cationic photoinitiator comprises a diaryl iodonium salt.

9. The solid film adhesive of claim 1, wherein the cationically curable resin comprises a solid epoxy resin including a glycidyl ether.

10. The solid film adhesive of claim 1, wherein the cationically curable resin is present in the range of about 10% to about 75% by weight of the total solids content of the solid film adhesive and the film forming polymeric binder is present in the range of about 25% to about 90% by weight of the total solids content of the solid film adhesive.

11. The solid film adhesive of claim 10, wherein the cationically curable resin is present in the range of about 35% to about 50% by weight of the total solids content of the solid film adhesive.

12. An actinic radiation activated, thermally curable solid film adhesive comprising a film forming polymeric binder, a cationically curable resin, and a cationic photoinitiator, wherein the solid film adhesive is processable at temperatures up to 120°

C. prior to exposure to actinic radiation without curing, has a latency period at room temperature following activation of the initiator, and is curable at temperatures above 50°

C. following activation of the initiator,

wherein the film forming polymeric binder comprises a polyester resin present in the range of about 25% to about 90% by weight of the solid content of the solid film adhesive,

wherein the cationically curable resin comprises a solid epoxy resin present in the range of about 35% to about 50% by weight of the solid content of the solid film adhesive, and

wherein the cationic photoinitiator comprises a triarylsulfonium salt or a diaryl iodonium salt.

13. The solid film adhesive of claim 12, further comprising less than 30% by weight of the film forming polymeric binder of a liquid epoxy resin.

14. A method of forming a solid film adhesive tape comprising:

mixing a film forming polymeric binder, a solid cationically curable resin, and a cationic photoinitiator to form a solid film adhesive;

thereafter

laminating the solid film adhesive to a first substrate at a temperature less than 120°

C. without curing the solid film adhesive;

thereafter

activating the photoinitiator; and

thereafter

curing the solid film adhesive at a temperature greater than 50°

C.

15. The method of claim 14, wherein the step of mixing comprises melt blending.

16. The method of claim 14, wherein the step of mixing comprises solvent blending the components in a common solvent.

17. The method of claim 14, further comprising the step of storing the solid film adhesive at room temperature for a period of at least twenty four hours prior to the step of activating the photoinitiator.

18. The method of claim 17, wherein a period of time elapses between the steps of activating and curing.

19. The method of claim 18 further comprising laminating the film adhesive to a second substrate contemporaneously with the step of curing.

20. The method of claim 14, wherein the photoinitiator comprises a triarylsulfonium salt or a diaryl iodonium salt.