One-part structural epoxy resin adhesives containing elastomeric tougheners capped with phenols and hydroxy-terminated acrylates or hydroxy-terminated methacrylates
AssigneeDow Global Technologies LLC
InventorsAndreas Lutz, Daniel Schneider
Life of this patent
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Abstract
Structural adhesives are prepared from an elastomeric toughener that contains urethane and/or urea groups, and have some terminal isocyanate groups that are capped with a phenol and other terminal isocyanate groups that are capped with a hydroxy-functional acrylate or a hydroxy-functional methacrylate. In certain embodiments, the presence of both types of capping on the toughener leads to higher impact peel strengths and a greater level of cohesive failure, than when the toughener is capped with a phenol an hydroxy-functional acrylate or hydroxy-functional methacrylate alone.
Claims13
1-15. (canceled)
An elastomeric toughener represented by structure (I):
- wherein p is from 1.5 to 8;
- wherein 80 to 99% of the A groups comprises a residue of an amino group of a primary aliphatic, cycloaliphatic, heterocyclic or araliphatic amine;
- an amino group of a secondary aliphatic, cycloaliphatic, heterocyclic or araliphatic amine or a hydroxyl group of a hydroxy-functional acrylate or methacrylate;
- 1 to 20% of the A groups comprises a residue of a phenol;
- Y is a residue of an isocyanate-terminated prepolymer after removal of the terminal isocyanate groups;
- and Y comprises at least one elastomeric segment.
A structural adhesive comprising:
- A) at least one epoxy resin;
- B) an elastomeric toughener represented by structure (I)
- wherein p is from 1.5 to 8;
- wherein 80 to 99% of the A groups comprises a residue of an amino group of a primary aliphatic, cycloaliphatic, heterocyclic or araliphatic amine;
- an amino group of a secondary aliphatic, cycloaliphatic, heterocyclic or araliphatic amine or a hydroxyl group of a hydroxy-functional acrylate, methacrylate;
- 1 to 20% of the A groups comprises a residue of a phenol;
- Y is a residue of an isocyanate-terminated prepolymer after removal of the terminal isocyanate groups;
- and Y comprises at least one elastomeric segment;
- C) one or more epoxy curing agents;
- D) a liquid rubber-modified epoxy resin, a core-shell rubber, or both a liquid rubber-modified epoxy resin and a core-shell rubber;
- E) a catalyst;
- and
- F) a latent free radical initiator that can be activated by radiation or by heating to a temperature of from 80 to 130° C.;
- wherein the adhesive cures rapidly at a temperature of 140° C. or higher but slowly if at all at a temperature of 80° C. or lower.
Dependencies are inferred from the claim text.