Granted Patent B2

US 9,181,463 · App. 13/821,748 · Granted Nov 10, 2015

Abstract

Claims (28)

1. A one-part structural adhesive comprising:

A) at least one epoxy resin;

B) a reactive elastomeric toughener containing capped isocyanate groups; and

C) one or more epoxy curing agents;

wherein all reactive elastomeric tougheners containing capped isocyanate groups present in the one-part structural adhesive are formed by

a) reacting an excess of a polyisocyanate with a 300-3000 equivalent weight polyol or with a mixture of a 300-3000 equivalent weight polyol and a branching agent, to form an isocyanate-terminated prepolymer;

b) reacting the isocyanate-terminated prepolymer with a chain extender to produce a chain extended, isocyanate-terminated prepolymer, and

c) capping 100% of the terminal isocyanate groups of the chain extended, isocyanate-terminated prepolymer with a capping agent selected from a monophenol, a polyphenol and an aminophenol.

2. The structural adhesive of claim 1 , wherein the 300-3000 equivalent weight polyol is a polyether, a hydroxyl-terminated polybutadiene or a mixture of a polyether and a hydroxyl-terminated polybutadiene.

3. The structural adhesive of claim 1 , wherein the chain extender contains two phenolic hydroxyl groups.

4. The structural adhesive of claim 1 wherein the capping agent is a monophenol.

5. The structural adhesive of claim 1 wherein the capping agent is a polyphenol.

6. The structural adhesive of claim 1 wherein the capping agent is an aminophenol.

7. The structural adhesive of claim 1 , wherein the epoxy resin includes at least one diglycidyl ether of a polyhydric phenol.

8. The structural adhesive of claim 1 , which contains at least one epoxide-terminated liquid rubber.

9. The structural adhesive of claim 1 , further comprising a latent catalyst which becomes active only upon exposure to elevated temperatures.

10. The structural adhesive of claim 9 wherein the latent catalyst is 2,4,6-tris(dimethylaminomethyl)phenol integrated into a poly(p-vinylphenol) matrix or 2,4,6-tris(dimethylaminomethyl)phenol integrated into a novolac resin.

11. The structural adhesive of claim 1 wherein the curing agent includes one or more of a boron trichloride/amine complex, a boron trifluoride/amine complex, dicyandiamide, melamine, diallylmelamine, acetoguanamine, benzoguanamine, 3-amino-1,2,4-triazole, adipic dihydrazide, stearic dihydrazide, isophthalic dihydrazide, semicarbazide, cyanoacetamide, and diaminodiphenylsulphones.

12. The structural adhesive of claim 1 further comprising one or more of calcium carbonate, calcium oxide, talc, carbon black, textile fibers, glass particles, glass fibers, aramid pulp, boron fibers, carbon fibers, a mineral silicate, mica, powdered quartz, hydrated aluminum oxide, bentonite, wollastonite, kaolin, fumed silica, silica aerogel, a polyurea compound, a polyamide compound, aluminum powder, iron powder, and microballoons having an average particle size of up to 200 microns and density of up to 0.2 g/cc.

13. A method comprising applying the structural adhesive of claim 1 to the surfaces of two members, and curing the structural adhesive to form an adhesive bond between the two members.

14. A one-part structural adhesive comprising:

A) at least one epoxy resin;

B) a reactive elastomeric toughener containing capped isocyanate groups; and

C) one or more epoxy curing agents;

wherein all reactive elastomeric tougheners containing capped isocyanate groups present in the one-part structural adhesive are formed by

a) reacting an excess of 1,6-hexamethylene diisocyanate with a 300-3000 equivalent weight polytetrahydrofuran, to form an isocyanate-terminated prepolymer;

b) reacting the isocyanate-terminated prepolymer with o,o′-diallylbisphenol A to produce a chain extended, isocyanate-terminated prepolymer, and

c) capping 100% of the terminal isocyanate groups of the chain extended, isocyanate-terminated prepolymer with a capping agent selected from o,o′-diallylbisphenol A and allylphenol.

Assignments (6)