Pet chew toys of rubber and polyamide, and methods of manufacture thereof
View Patent ↗A pet chew toy comprising a blend containing a polyamide terpolymer and a diene elastomer, wherein the diene elastomer is crosslinked and the polyamide terpolymer has a Tm in the range of 120° C. to 250° C.
1. A method of making a pet chew toy comprising:
providing a first material composition having a first Shore durometer hardness, the first material composition comprising a blend containing a polyamide terpolymer and a diene elastomer, wherein the polyamide terpolymer is formed of three different polyamide segments and has a melt temperature in a range of 120° C. to 250° C., and wherein the diene elastomer is crosslinked;
providing a second material composition having a second Shore durometer hardness, the first Shore durometer hardness of the first material composition being higher than the second Shore durometer hardness of the second material composition, the second material composition comprising an elastomer;
forming two end portions of the pet chew toy with the first material composition; and
forming a central shaft portion of the pet chew toy with the second material composition, wherein the central shaft portion is joined to each end portion.
2. The method of claim 1 wherein:
forming the two end portions and the central shaft portion of the pet chew toy are each performed by injection molding.
3. The method of claim 1 wherein:
forming the two end portions of the pet chew toy with the first material composition is performed in a first molding apparatus; and
providing the first material composition comprising the polyamide terpolymer and the diene elastomer further comprises mixing the polyamide terpolymer and the diene elastomer in a mixing apparatus prior to an introduction of the first material composition to the first molding apparatus.
4. The method of claim 3 wherein:
mixing the polyamide terpolymer and the diene elastomer in the mixing apparatus further includes cross-linking the first material composition comprising the polyamide terpolymer and the diene elastomer in the mixing apparatus.
5. The method of claim 3 wherein:
providing the first material composition comprising the polyamide terpolymer and the diene elastomer further comprises forming the first material composition comprising the polyamide terpolymer and the diene elastomer into a sheet after mixing the polyamide terpolymer and the diene elastomer in the mixing apparatus and cutting the sheet into smaller sections prior to the introduction of the first material composition to the first molding apparatus.
6. The method of claim 3 wherein:
the first molding apparatus is an injection molding apparatus.
7. The method of claim 3 wherein:
the mixing apparatus is an intensive mixing apparatus.
8. The method of claim 3 wherein:
forming the central shaft portion of the pet chew toy with the second material composition is performed in a second molding apparatus.
9. The method of claim 8 wherein:
the second molding apparatus is an injection molding apparatus.
10. The method of claim 3 wherein:
the central shaft portion is joined to each end portion by at least one of melt bonding and by a mechanical lock.
11. The method of claim 1 wherein:
the polyamide terpolymer has a melt temperature in a range of 120° C. to 200° C.
12. The method of claim 1 wherein:
the polyamide terpolymer has a melt temperature in a range of 120° C. to 150° C.
13. The method of claim 1 wherein:
the polyamide terpolymer comprises a terpolymer of the following three polyamide homopolymer segments:
14. The method of claim 1 wherein:
the polyamide terpolymer is in a range of 30% by weight to 95% by weight of the first material composition.
15. The method of claim 1 wherein:
the diene elastomer is in a range of 5% by weight to 50% by weight of the first material composition.
16. The method of claim 1 wherein:
the polyamide terpolymer and the diene elastomer of the first material composition are each present at a selected weight ratio, and the weight ratio of the diene elastomer to the polyamide terpolymer is 1:10 to 1:1.
17. The method of claim 1 wherein:
the diene elastomer of the first material composition comprises cis-1,4-polyisoprene.
18. The method of claim 1 wherein:
the first Shore durometer hardness of the first material composition is a Shore A durometer hardness greater than 70.
19. The method of claim 1 wherein:
the second Shore durometer hardness of the second material composition is a Shore A durometer hardness less than 65.