Structural adhesive compositions
An adhesive composition is disclosed. The adhesive composition comprises an epoxy-containing component; rubber particles having a core-shell structure; and a curing component comprising a mixture of an amine-containing compound substantially free of hydroxyl functional groups and a polymeric phenol-containing compound, wherein the amine-containing compound comprises primary and/or secondary amino groups, and wherein the curing component chemically reacts with the epoxy-containing component upon activation from an external energy source. Also disclosed are methods of preparing the adhesive composition and for forming a bonded substrate with the adhesive composition. Further disclosed are curing components for an adhesive composition and methods of making the curing components.
1. A curing component comprising a mixture of an amine-containing compound having a structure of formula (I):
wherein each R 1 is independently H or a C 1 -C 18 alkyl group; R 2 is oxygen; each R 3 is independently absent or C 1 -C 4 divalent alkyl or divalent cycloaliphatic, wherein the amine-containing compound comprises primary and/or secondary amino groups and tertiary amines in an amount of less than 2% by weight based on total weight of the amine-containing compound and is substantially free of hydroxyl functional groups, and a polymeric phenol-containing compound; wherein the curing component is ground to a D97 of no more than 500 μm using an air classifying mill; and wherein the amine-containing compound is blocked by the polymeric phenol-containing compound in the absence of activation from an external energy source.
2. The curing component of claim 1 , wherein the amine-containing compound has an amine equivalent weight of at least 30.
3. The curing component of claim 1 , wherein the amine-containing compound further comprises dipropylenetriamine.
4. The curing component of claim 1 , wherein the polymeric phenol-containing compound has a phenol equivalent weight of at least 62.
5. The curing component of claim 1 , wherein the polymeric phenol-containing compound comprises a phenol formaldehyde resin.
6. The curing component of claim 1 , wherein the mixture is substantially free of solvent.
7. An adhesive composition comprising:
an epoxy-containing component;
rubber particles having a core-shell structure; and
the curing component of claim 1 .
8. The adhesive composition of claim 7 , wherein the epoxy-containing component is present in an amount of from 50% to 90% by weight based on total composition weight.
9. The adhesive composition of claim 7 , wherein the curing component is present in an amount of from 0.2% to 15% by weight based on total composition weight.
10. The adhesive composition of claim 7 , further comprising a secondary latent curing catalyst.
11. The adhesive composition of claim 7 , wherein the adhesive composition is substantially free of solvent.
12. The adhesive composition of claim 7 , wherein the polymeric phenol-containing compound blocks the amine-containing compound from reacting with the epoxy-containing component in the absence of activation from the external energy source.
13. A method for forming a bond between two substrates comprising:
applying the adhesive composition of claim 7 to a first substrate;
contacting a second substrate to the adhesive composition such that the adhesive composition is located between the first substrate and the second substrate; and
applying an external energy source to cure the adhesive composition.
14. The curing component of claim 1 , wherein the amine-containing compound and the polymeric phenol-containing compound are present in a molar ratio of from 1.5:1 to 1:3.
15. The method of claim 13 , wherein the external energy source comprises thermal heating to a temperature of at least 100° C.
16. A curing component comprising a mixture of an amine-containing compound comprising an alkyl polyetheramine and/or a cycloaliphatic polyetheramine, wherein the amine-containing compound comprises primary and/or secondary amino groups and tertiary amines in an amount of less than 2% by weight based on total weight of the amine-containing compound and is substantially free of hydroxyl functional groups, and a polymeric phenol-containing compound comprising a phenol-equivalent weight of at least 124; wherein the curing component is ground to a D97 of no more than 500 μm using an air classifying mill; and wherein the amine-containing compound is blocked by the polymeric phenol-containing compound in the absence of activation from an external energy source.
17. The curing component of claim 16 , wherein the amine-containing compound has an amine equivalent weight of at least 30.
18. The curing component of claim 16 , wherein the amine-containing compound further comprises dipropylenetriamine.
19. The curing component of claim 16 , wherein the polymeric phenol-containing compound comprises a phenol formaldehyde resin.
20. The curing component of claim 16 , wherein the mixture is substantially free of solvent.
21. An adhesive composition comprising:
an epoxy-containing component;
rubber particles having a core-shell structure; and
the curing component of claim 16 .
22. The adhesive composition of claim 21 , wherein the epoxy-containing component is present in an amount of from 50% to 90% by weight based on total composition weight.
23. The adhesive composition of claim 21 , wherein the curing component is present in an amount of from 0.2% to 15% by weight based on total composition weight.
24. A method for forming a bond between two substrates comprising:
applying the adhesive composition of claim 21 to a first substrate;
contacting a second substrate to the adhesive composition such that the adhesive composition is located between the first substrate and the second substrate; and
applying an external energy source to cure the adhesive composition.
25. A curing component comprising a mixture of an amine-containing compound having a structure of formula (I):
wherein each R 1 is independently H or a C 1 -C 18 alkyl group; R 2 is oxygen; each R 3 is independently absent or C 1 -C 4 divalent alkyl or divalent cycloaliphatic, wherein the amine-containing compound comprises primary and/or secondary amino groups and tertiary amines in an amount of less than 2% by weight based on total weight of the amine-containing compound and is substantially free of hydroxyl functional groups, and a polymeric phenol-containing compound; wherein the curing component is a powder having a D97 particle size of no more than 500 μm; and wherein the amine-containing compound is blocked by the polymeric phenol-containing compound in the absence of activation from an external energy source.
26. The curing component of claim 25 , wherein the amine-containing compound has an amine equivalent weight of at least 30 and/or the polymeric phenol-containing compound has a phenol equivalent weight of at least 62.
27. The curing component of claim 25 , wherein the amine-containing compound further comprises dipropylenetriamine and/or the polymeric phenol-containing compound comprises a phenol formaldehyde resin.
28. The curing component of claim 25 , wherein the amine-containing compound and the polymeric phenol-containing compound are present in a molar ratio of from 1.5:1 to 1:3.
29. An adhesive composition comprising:
an epoxy-containing component;
rubber particles having a core-shell structure; and
the curing component of claim 25 .
30. The adhesive composition of claim 29 , wherein the epoxy-containing component is present in an amount of from 50% to 90% by weight based on total composition weight and/or wherein the curing component is present in an amount of from 0.2% to 15% by weight based on total composition weight.
31. A method for forming a bond between two substrates comprising:
applying the adhesive composition of claim 29 to a first substrate;
contacting a second substrate to the adhesive composition such that the adhesive composition is located between the first substrate and the second substrate; and
applying an external energy source to cure the adhesive composition.
32. A curing component comprising a mixture of an amine-containing compound comprising an alkyl polyetheramine and/or a cycloaliphatic polyetheramine, wherein the amine-containing compound comprises primary and/or secondary amino groups and tertiary amines in an amount of less than 2% by weight based on total weight of the amine-containing compound and is substantially free of hydroxyl functional groups, and a polymeric phenol-containing compound comprising a phenol-equivalent weight of at least 124; wherein the curing component is a powder having a D97 particle size of no more than 500 μm; and wherein the amine-containing compound is blocked by the polymeric phenol-containing compound in the absence of activation from an external energy source.
33. The curing component of claim 32 , wherein the amine-containing compound has an amine equivalent weight of at least 30.
34. The curing component of claim 32 , wherein the amine-containing compound further comprises dipropylenetriamine and/or the polymeric phenol-containing compound comprises a phenol formaldehyde resin.
35. An adhesive composition comprising:
an epoxy-containing component;
rubber particles having a core-shell structure; and
the curing component of claim 32 .
36. The adhesive composition of claim 35 , wherein the epoxy-containing component is present in an amount of from 50% to 90% by weight based on total composition weight and/or the curing component is present in an amount of from 0.2% to 15% by weight based on total composition weight.
37. A method for forming a bond between two substrates comprising:
applying the adhesive composition of claim 35 to a first substrate;
contacting a second substrate to the adhesive composition such that the adhesive composition is located between the first substrate and the second substrate; and
applying an external energy source to cure the adhesive composition.