High expansion two-component structural foam

• US 20040131840A1
• Filed: 01/03/2003
• Published: 07/08/2004
• Est. Priority Date: 01/03/2003
• Status: Active Grant

• Current Assignee: Henkel KGaA (Henkel AG & Co KGaA)
• Original Assignee: Henkel KGaA (Henkel AG & Co KGaA)
• Inventors: Agarwal, Rajat K., Ferguson, Gregory A., Koshy, Vettithara C.
• Granted Patent: US 7,119,149 B2
• Time in Patent Office: Days
• US Class Current: 428/317.9
• CPC Class Codes: C08J 2207/02 Adhesive
• CPC Class Codes: C08J 2363/00 Characterised by the use of epoxy resins; Derivatives of epoxy resins
• CPC Class Codes: C08J 9/32 from compositions containing microballoons, e.g. syntactic foams
• CPC Class Codes: H02K 1/276 Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
• CPC Class Codes: Y10T 428/249986 Void-containing component contains also a solid fiber or solid particle
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31725 Of polyamide

Abstract

The present invention is directed to a high expansion two-component structural foam that expands to about twice its original volume while maintaining good cell structure. The foam of the present invention is based on epoxy resins. Each component of the foam system exhibits storage stability, e.g., no phase separation, yet reacts when combined to provide a cured material having exceptionally good compression strength and modulus. The blowing system used to prepare the foam produces a foam which is uniform in appearance and is essentially free of the large voids often found in conventional two-part thermosettable compositions, even when a relatively large mass is utilized.

Claims

1. A two component system capable of being cured to provide a structural reinforcement adhesive, said two component system comprising a Component A and a Component B, wherein said Component A comprises at least one epoxy resin and Component B comprises a curing system that comprises at least one amine curative, and wherein said two-component system comprises a blowing system that comprises at least one high-temperature thermally-activated blowing agent and at least one low-temperature thermally-activated blowing agent.

2. The two component system of claim 1 wherein the high- and low-temperature blowing agents are present at a weight ratio in the range of from about 1:

1 to about 7;

1 respectively.

3. The two component system of claim 2, wherein said weight ratio is in the range of from about 2:

1 to 6;

1.

4. The two component system of claim 1 wherein the at least one high-temperature thermally-activated blowing agent has an onset temperature in the range of from about 110°

C. to about 150°

C. and wherein said at least one low-temperature thermally-activated blowing agent has an onset temperature in the range of from about 75°

C. to about 105°

C.

5. The two component system of claim 1 wherein the at least one high-temperature thermally-activated blowing agent has an onset temperature in the range of from about 110°

C. to about 130°

C. and wherein said at least one low-temperature thermally-activated blowing agent has an onset temperature in the range of from about 90°

C. to about 100°

C.

6. The two component system of claim 1 wherein the at least one high-temperature thermally-activated blowing agent has a maximum temperature in the range of from about 165°

C. to about 210°

C. and wherein said at least one low-temperature thermally-activated blowing agent has a maximum temperature in the range of from about 115°

C. to about 150°

C.

7. The two component system of claim 1 wherein the at least one high-temperature thermally-activated blowing agent has a maximum temperature in the range of from about 180°

C. to about 195°

C. and wherein said at least one low-temperature thermally-activated blowing agent has a maximum temperature in the range of from about 135°

C. to about 150°

C.

8. The two component system of claim 1 wherein the at least one high-temperature thermally-activated blowing agent has a maximum temperature greater than the internal temperature of the adhesive during curing and wherein said at least one low-temperature thermally-activated blowing agent has a maximum temperature less than the internal temperature of the adhesive during curing.

9. The composition of claim 1 wherein said Component A comprises from about 0.5 to about 10 wt % high-temperature thermally-activated blowing agent and from about 0.5 to about 5 wt % low-temperature thermally-activated blowing agent.

10. The composition of claim 1 wherein said Component A comprises from about 2 to about 8 wt % high-temperature thermally-activated blowing agent and from about 1 to about 4 wt % low-temperature thermally-activated blowing agent.

11. The two component system of claim 1 wherein said high- and low-temperature thermally-activated blowing agents each comprise expandable microspheres.

12. The two component system of claim 1 wherein said Component A comprises at least one epoxy resin which is a glycidyl ether of a polyhydric phenol.

13. The two component system of claim 1 wherein the curative system of Component B comprises at least one aliphatic polyamine, at least one amidoamine, at least one alcohol, and at least one adduct of a polyamine and an epoxide.

14. A two component system capable of being expanded and cured to provide a structural reinforcement foam, said two component system comprising a Component A and a Component B, wherein said Component A comprises:

at least one epoxy resin which is a glycidyl ether of a polyhydric phenol;

hollow inorganic microspheres;

a blowing system comprising at least one high-temperature thermally-activated blowing agent and at least one low-temperature thermally-activated blowing agent;

and wherein said Component B comprises;

a curative system comprising at least one amine curative; and

hollow inorganic microspheres.

15. The two component system of claim 14 wherein Component A comprises at least one epoxy resin which is a diglycidyl ether of bisphenol A.

16. The two component system of claim 14 wherein said high- and low-temperature thermally-activated blowing agents each comprise expandable microspheres.

17. The two component system of claim 14 wherein the at least one high-temperature thermally-activated blowing agent has an onset temperature in the range of from about 110°

C. to about 125°

C. and wherein said at least one low-temperature thermally-activated blowing agent has an onset temperature in the range of from about 90°

C. to about 100°

C.

18. The two component system of claim 14 wherein the high- and low-temperature blowing agents are present at a weight ratio in the range of from about 1:

1 to about 7;

1 respectively.

19. The two component system of claim 14 wherein the curative system of Component B comprises:

at least one aliphatic polyamine;

at least one amidoamine;

at least one alcohol; and

at least one adduct of a polyamine and an epoxide.

20. The two component system of claim 19 wherein at least one aliphatic polyamine corresponds to the generic structure

21. The two component system of claim 19 wherein at least one amidoamine is an aliphatic amidoamine prepared by reacting an aliphatic polyamine with a fatty acid.

22. The two component system of claim 19 wherein at least one alcohol is an aromatic alcohol.

23. The two component system of claim 19 wherein at least one alcohol is a polyhydric phenol.

24. The two component system of claim 19 wherein at least one alcohol is bisphenol A.

25. The two component system of claim 19 wherein at least one adduct is an adduct of an aliphatic polyamine corresponding to the general structure

26. The two component system of claim 19 wherein at least one adduct is an adduct of a glycidyl ester.

27. The two component system of claim 19 wherein at least one adduct is an adduct of a glycidyl ester of C₂-C₂₄ aliphatic carboxylic acid.

28. The two component system of claim 14 wherein Component A has the following composition:

29. The two component system of claim 14 wherein Component B has the following composition:

30. The composition of claim 14 wherein said Component A comprises from about 0.5 to about 10 wt % high-temperature thermally-activated blowing agent and from about 0.5 to about 5 wt % low-temperature thermally-activated blowing agent.

31. The composition of claim 14 wherein said Component A comprises from about 2 to about 8 wt % high-temperature thermally-activated blowing agent and from about 1 to about 4 wt % low-temperature thermally-activated blowing agent.

32. The composition of claim 14 wherein said Component A comprises about 4.5 wt % high-temperature thermally-activated blowing agent and about 1.8 wt % low-temperature thermally-activated blowing agent, and wherein the high-temperature thermally-activated blowing agent and the low-temperature thermally-activated blowing agent each are expandable micro spheres.

33. A composition comprising:

34. The composition of claim 33 wherein the blowing system comprises from about 2 to about 8 wt % high-temperature thermally-activated blowing agent and from about 1 to about 4 wt % low-temperature thermally-activated blowing agent.

35. The composition of claim 33 wherein the blowing system comprises about 4.5 wt % high-temperature thermally-activated blowing agent and about 1.8 wt % low-temperature thermally-activated blowing agent.

36. The composition of claim 33 wherein the high-temperature thermally-activated blowing agent and the low-temperature thermally-activated blowing agent each are expandable microspheres.

37. A method of curing a thermosettable composition comprised of:

(a) at least one epoxy resin;

(b) hollow glass microspheres; and

(c) a blowing system comprising;

(i) at least one high-temperature thermally-activated blowing agent, and

(ii) at least one low-temperature thermally-activated blowing agent;

said method comprising combining said thermosettable composition with a curative system comprising at least one amine curative and initiating exothermic reaction of the thermosettable composition and the curative system.

38. A method of preparing a structural reinforcing foam comprising combining:

(a) at least one epoxy resin;

(b) hollow glass microspheres;

(c) a blowing system comprising;

(i) at least one high-temperature thermally-activated blowing agent, and

(ii) at least one low-temperature thermally-activated blowing agent; and

(d) a curative system comprising at least one amine curative;

and initiating exothermic reaction of (a) and (d) and expansion of the blowing system.

39. A method of reinforcing a substrate having a surface, said method comprising combining at least one epoxy resin, hollow glass microspheres, and a blowing system comprised of at least one high-temperature thermally-activated blowing agent, and at least one low-temperature thermally-activated blowing agent;

and a curative system comprised of at least one amine curative to form a mixture, applying said mixture to said surface, and curing said mixture.

40. A method of reinforcing a structural member having a cavity, said method comprising:

(A) combining

(a) at least one epoxy resin;

(b) hollow glass microspheres; and

(c) a blowing system comprising;

(i) at least one high-temperature thermally-activated blowing agent, and

(ii) at least one low-temperature thermally-activated blowing agent; and

(vii) a curative system comprised of at least one amine curative to form a pumpable mixture;

(B) introducing said pumpable mixture into said cavity; and

(C) curing and expanding said pumpable mixture to provide a structural reinforcement foam within said cavity.