PE-based crosslinked elastomeric foam with high filler loadings for making shockpads and articles used in footwear and flooring applications
View Patent ↗Crosslinked foams having high filler loadings, which may be formed from A) a polyolefin having a crystallinity of 21 percent or less, an ethylene vinyl acetate copolymer having a vinyl acetate content of less than 15 mole percent, or a combination thereof; B) a polyolefin having a viscosity between 500 and 20,000 cP, as measured using ASTM D1084 (Brookfield Viscosity at 350° F.); and C) a filler, wherein the crosslinked foam includes from 10 to 80 parts filler per hundred parts of components A, B, and C, by weight. In other aspects of embodiments disclosed herein, the crosslinked foam may optionally include one or more of: D) at least one polyolefin having a crystallinity of greater than 21 weight percent, an ethylene vinyl acetate copolymer having a vinyl acetate content of 15 mole percent or greater, or a combination thereof; and E) a scorch retarder.
1. A crosslinked foam for use in footwear or as a shockpad, the foam comprising the reaction product of:
A. a first polyolefin having a crystallinity of 21 percent or less, an ethylene vinyl acetate copolymer having a vinyl acetate content of less than 15 mole percent, or a combination thereof;
B. a second polyolefin having a viscosity between 500 and 20,000 cP, as measured using ASTM D1084, the second polyolefin having a crystallinity of greater than 21 percent;
C. a filler, wherein the crosslinked foam comprises from 40 to 80 parts filler per hundred parts of components A, and B, by weight;
D. a scorch retarder; and
E. a third polyolefin having a crystallinity of greater than 21 percent;
wherein the crosslinked foam, prior to crosslinking, comprises a thermoplastic composition, the thermoplastic composition comprising:
i. 20 to 80 weight percent of component A;
ii. 25 to 75 weight percent of component E;
iii. greater than 0 to 6 weight percent of component B;
iv. greater than 0 to 1 weight percent of component D; and
v. 27 to 50 weight percent of component C;
wherein the above weight percentages are based on the total weight of components A, B, C, D, and E.
2. The crosslinked foam of claim 1 , wherein components A and B were crosslinked using a peroxide curing agent.
3. The crosslinked foam of claim 1 , wherein components A and B were crosslinked using a heat activated curing system or a radiation induced curing system.
4. The crosslinked foam of claim 3 , wherein the heat activated curing system comprises at least one of sulfur and an epoxy.
5. The crosslinked foam of claim 3 , wherein the radiation activated curing system comprises at least one of e-beaming and gamma radiation.
6. The crosslinked foam of claim 1 , wherein components A and B were crosslinked using a silane derived compound.
7. The crosslinked foam of claim 1 wherein the foam comprises at least about 30 percent by weight gel content as measured using xylene extractables.
8. The crosslinked foam of claim 1 , wherein the filler comprises at least one of regrind and calcium carbonate.
9. The crosslinked foam of claim 1 , wherein the crosslinked foam has a density within the range from about 50 to about 500 kg/m 3 .
10. The crosslinked foam of claim 1 , wherein the crosslinked foam has an open cell volume of less than 30 percent.
11. The crosslinked foam of claim 1 , wherein the crosslinked foam has a thickness in the range from 1 to 80 mm.
12. An artificial turf, carpet, or flooring comprising a shock pad as defined in claim 1 .
13. A shoe, boot, or footwear comprising a shock pad as defined in claim 1 .