STRUCTURAL ADHESIVES

• US 20110098382A1
• Filed: 04/07/2009
• Published: 04/28/2011
• Est. Priority Date: 04/09/2008
• Status: Active Grant

• Current Assignee: Zephyros, Inc.
• Original Assignee: Zephyros, Inc.
• Inventors: Czaplicki, Michael
• Granted Patent: US 11,248,145 B2
• Time in Patent Office: Days
• US Class Current: 523/453
• CPC Class Codes: C08G 2650/56 Polyhydroxyethers, e.g. phenoxy resins
• CPC Class Codes: C08G 59/186 with acids
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/22 Macromolecular compounds not provided for in C08L2666/16 - C08L2666/20
• CPC Class Codes: C08L 71/00 Compositions of polyethers obtained by reactions forming an ether link in the main chain of polyacetals C08L59/00; of epoxy resins C08L63/00; of polythioether-ethers C08L81/02; of polyether-sulfones C08L81/06; 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 171/00 Adhesives based on polyethers obtained by reactions forming an ether link in the main chain based on polyacetals C09J159/00; based on epoxy resins C09J163/00; based on polythioether-ethers C09J181/02; based on polyethersulfones C09J181/06; Adhesives based on derivatives of such polymers
• CPC Class Codes: C09J 2400/163 in the substrate
• CPC Class Codes: C09J 5/06 involving heating of the applied adhesive

Abstract

An adhesive formulation comprising i) an adduct of an epoxy resin and an elastomer, ii) a phenoxy resin; a core/shell polymer; iv) a curing agent which provides a structural adhesive with improved low temperature impact strength particularly useful for bonding metal especially in the automotive industry.

Claims

1. An adhesive formulation comprising

i) an adduct of an epoxy resin and an elastomer;

ii) a phenoxy resin;

iii) a core/shell polymer;

iv) a curing agent.

2. An adhesive formulation according to claim 1, wherein the formulation contains from about 5% to 20% by weight of the adduct based on the activatable material.

3. An adhesive formulation according to claim 1, wherein the adduct includes about 1:

5 to 5;

1 parts of epoxy to elastomer.

4. An adhesive formulation according to claim 1, wherein the elastomer in the adduct is selected from the group consisting of:

natural rubber, styrene-butadiene rubber, polyisoprene, polyisobutylene, polybutadiene, isoprene-butadiene copolymer, neoprene, nitrile rubber (e.g., a butyl nitrile, such as carboxy-terminated butyl nitrile), butyl rubber, polysulfide elastomer, acrylic elastomer, acrylonitrile elastomers, silicone rubber, polysiloxanes, polyester rubber, diisocyanate-linked condensation elastomer, EPDM (ethylene-propylene diene rubbers), chlorosulphonated polyethylene, fluorinated hydrocarbons and any combination thereof.

6. An adhesive formulation according to claim 1, wherein the phenoxy resin is of the formula

7. An adhesive formulation according claim 1, wherein the phenoxy resin is supplied as a solution.

8. An adhesive formulation according to claim 7 in which the solvent is a liquid epoxy resin.

9. An adhesive formulation according to claim 1, wherein the formulation contains no more than 20% by weight of the phenoxy resin.

10. An adhesive formulation according to claim 1, wherein the core/shell polymer has a ductile core and a rigid shell which is compatible with the other components of the formulation.

11. An adhesive formulation according to claim 1, wherein the first and second polymeric materials of the core/shell polymer include elastomers, polymers, thermoplastics, copolymers, or any combination thereof.

12. An adhesive formulation according to claim 11 in which the first polymeric material, the second polymeric material or both include or are at least 70% or more by weight one or more thermoplastics.

13. An adhesive formulation according to claim 12 in which the polymeric materials are selected from the group consisting of:

styrenics, acrylonitriles, acrylates, acetates, polyamides, polyethylenes and any combination thereof.

14. An adhesive formulation according to claim 1 wherein the core/shell polymer is a graft copolymer in which styrene, acrylonitrile or methyl methacrylate, are grafted onto a core made from polymers of soft or elastomeric compounds such as butadiene or butyl acrylate.

15. An adhesive according to claim 14 in which the core polymer includes other copolymerizable containing compounds, selected from styrene, vinyl acetate, methyl methacrylate, butadiene and isoprene.

16. An adhesive according to claim 14 in which the core polymer material includes a cross linking monomer having two or more nonconjugated double bonds.

17. An adhesive according to claim 14 in which the shell portion is polymerized from alkyl acrylates and/or methacrylates.

18. An adhesive formulation according to claim 1 wherein the formulation contains from about 5% to about 30% of the core shell polymer.

20. An adhesive formulation according to claim 1 wherein the curing agent is selected from aliphatic or aromatic amines or their respective adducts, amidoamines, polyamides, cycloaliphatic amines, anhydrides, polycarboxylic polyesters, isocyanates, phenol-based resins (e.g., phenol or cresol novolak resins, copolymers such as those of phenol terpene, polyvinyl phenol, or bisphenol-A formaldehyde copolymers, bishydroxyphenyl alkanes or the like), or mixtures thereof.

21. An adhesive formulation according to claim 20 in which the curing agent is selected from modified and unmodified polyamines or polyamides such as triethylenetetramine, diethylenetriamine tetraethylenepentamine, cyanoguanidine and dicyandiamides.

24. An adhesive formulation according to claim 1, wherein the formulation contains between about 2% and about 15% by weight liquid epoxy resin.

31. An adhesive formulation according to claim 1, wherein the formulation contains one or more liquid polysulfides.

32. An adhesive formulation according to claim 1, comprising from about 3% to about 25% by weight of the epoxy/elastomer adduct, from about 3% to about 20% of the phenoxy resin, from about 5% to about 30% of the core/shell polymer;

and from about 1% to about 10% of a curing agent.

33. An adhesive formulation according to claim 32 containing about 5% to about 75% of one or more epoxy resins, about 0.2% to about 3% of a cure accelerator, about 0.1% to about 50% mineral filler, and about 0.1% to about 3.0% clay and/or silica.

35. A process for the preparation of an adhesive formulation according to claim 1 comprising supplying an epoxy elastomer adduct and a core/shell polymer in solid form and blending with a solution of the phenoxy resin.

36. A process according to claim 35 in which the epoxy resin is a liquid epoxy resin.

5. An adhesive formulation according to claim 5 in which the elastomer/epoxy adduct is derived from a butadiene acrylonitrile rubber.

19. (canceled)

22-23. -23. (canceled)

25-30. -30. (canceled)

34. (canceled)

37. An adhesive having a strength when cured in the wedge impact test at −

40°

C. of greater than 20 N/mm.

38-45. -45. (canceled)