Polyurethane foams and method of manufacture thereof
View Patent ↗A thermoformable polyurethane foam having excellent compression set resistance, and a thermoformable polyurethane foam having excellent compression set resistance and shape retention under load. In another embodiment, at least one additional layer of a polyurethane foam is integrally bonded to the thermoformable foam. A moisture management system for polyurethane foams is also described. The foams have particular utility as shoe sole inserts.
1. A polyurethane foam formed from a composition comprising:
an isocyanate-containing component having an average isocyanate functionality less than or equal to 2.15;
an active hydrogen-containing component having an average functionality less than or equal to 2.14;
a catalyst; and
a surfactant, wherein the foam is thermoformable, has a density of 10 to 40 pounds per cubic foot, and a room temperature compression set resistance of less than or equal to 10% after 50% compression for 22 hours.
2. The foam of claim 1 , wherein the active hydrogen-containing component has an average functionality greater than or equal to or equal to 2.065.
3. The foam of claim 1 , having a thermoformability factor greater than or equal to 0.5.
4. The foam of claim 1 , having a recovery factor greater than or equal to 0.4.
5. The foam of claim 1 , having a 50° C. compression set resistance of lees than or equal to 30% after 50% compression for 22 hours.
6. The foam of claim 1 , having a thermoformability factor greater than or equal to 0.6, a recovery factor greater than or equal to 0.5, and a room temperature compression set resistance of less than or equal to 10% after 50% compression for 22 hours.
7. The foam of claim 1 , having a thermoformability factor greater than or equal to 0.6, a recovery factor greater than or equal to 0.5, a room temperature compression set resistance less than or equal to 10%, and a 50° C. compression set resistance of less than or equal to 30% after compression to 50% for 22 hours.
8. The composition of claim 1 , wherein the active hydrogen-containing component comprises a polyol.
9. The composition of claim 8 , wherein the polyol is a mixture of a polyether polyol and a polyester polyol.
10. The composition of claim 8 , wherein the polyester polyol is selected from the group consisting of aromatic polyesters and caprolactone-based polyesters.
11. The composition of claim 8 , wherein the polyether polyol is selected from a group consisting of polypropylene ether based polyether triol.
12. The composition of claim 8 , wherein the polyether polyol is selected from a group consisting of a mixture of polypropylene ether based polyether triol and diol.
13. The composition of claim 12 , further comprising a moisture management system.
14. The composition of claim 1 , wherein the average functionality of the isocyanate-containing component is 1.80 to 2.10.
15. The composition of claim 1 , wherein the average functionality of the isocyanate-containing component is 2.00 to 2.05.
16. The composition of claim 1 , wherein the average functionality of the isocyanate-containing component is 2.00.
17. The composition of claim 1 , further comprising a moisture management system.
18. The composition of claim 17 , wherein the moisture management system is selected from the group of additives consisting of sodium carboxymethylcellulose, poly(N-vinyl acrylamide), sodium acrylate, potassium acrylate, wood powder, corn starch, calcium carbonate, and mixtures comprising one of the foregoing additives.
19. The composition of claim 18 , wherein the moisture management system is selected from the group of additives consisting of sodium carboxymethylcellulose, poly(N-vinyl acrylamide), calcium carbonate, and mixtures comprising one of the foregoing additives.
20. A shoe insert comprising the foam of claim 1 .