Adhesive compositions, manufacture and use thereof
View Patent ↗The invention relates to an adhesive composition having an added component of rubber-epoxy such as XNBR-epoxy adducts. It was found that the new adhesive composition significantly reduces meander formation in the making of automotive parts.
1. An adhesive composition comprising
a) an epoxy resin that includes a liquid diglycidyl ether of bisphenol A;
b) a blocked polyurethane toughener;
c) a curing agent that includes dicyandiamide; and
d) a rubber-epoxy adduct component with a Mw value above 60,000 Da, the adhesive composition having a viscosity value—from 307 to 1350 Pas at 25° C.
2. An adhesive composition consisting essentially of
a) at least one liquid diglycidyl ether of bisphenol A and optionally at least one solid diglycidyl ether of bisphenol A;
b) a blocked polyurethane toughener;
c) a curing agent that includes dicyandiamide;
d) a rubber-epoxy adduct component with a Mw value above 60,000 Da;
e) and optionally one or more of a filler, a wetting agent, a colorant and an adhesion promoter, the adhesive composition having a viscosity value—from 307 to 1350 Pa·s at 25° C.
3. The adhesive composition according to claim 2 , wherein the rubber-epoxy component comprises carboxylated acrylonitrile butadiene rubber-epoxy adducts.
4. The adhesive composition according to claim 2 wherein the epoxy resin further includes a solid diglycidyl ether of bisphenol A.
5. The adhesive composition according to claim 2 wherein the rubber-epoxy adduct component has about 1 to 15 wt % of rubber elastomer.
6. The adhesive composition according to claim 2 wherein the rubber-epoxy adduct component has about 3 to 10 wt % of rubber elastomer.
7. The adhesive composition according to claim 2 , wherein the rubber-epoxy adduct component has a molecular weight of Mw above 80,000 and Mn above 10,000.
8. The adhesive composition according to claim 2 wherein the rubber elastomer is a combination of at least two different carboxylated nitrile butadiene rubbers.
9. The adhesive composition according to claim 2 wherein the composition comprises at least about 4 wt % of the rubber-epoxy adduct component.
10. The adhesive composition according to claim 2 wherein the composition comprises at least about 8 wt % of the rubber-epoxy adduct component.
11. The adhesive composition according to claim 2 wherein the composition comprises at least about 12 wt % of the rubber-epoxy adduct component.
12. The adhesive composition according to claim 2 wherein the rubber-epoxy adduct component has a viscosity above 50,000 mPa·s at 25° C.
13. The adhesive composition according to claim 2 wherein the rubber-epoxy adduct component has a viscosity above 300,000 mPa·s at 25° C.