Claims
- 1. A method for making a hydrophilic ester polyurethane foam, comprising:
(a) forming a polyurethane foam by mixing together the following components:
(i) 100 parts by weight of an ester polyol; (ii) from 20.0 to 62.0 parts by weight, based on 100 parts polyol, of an isocyanate, wherein the isocyanate index is 120 or less; and (iii) from 1.0 to 3.0 parts by weight, based on 100 parts polyol, of a stabilizing surfactant; (b) treating the polyurethane foam in a caustic bath to form the hydrophilic ester polyurethane foam, and (c) felting the treated foam, wherein the hydrophilic ester polyurethane foam has a water absorption rate of at least 20 pounds of water per square foot per minute.
- 2. The method of claim 1, wherein the stabilizing surfactant is a silicone surfactant.
- 3. The method of claim 1, further comprising from 1.0 to 5.0 parts by weight, based on 100 parts polyol, of a blowing agent as a component.
- 4. The method of claim 3, wherein the blowing agent is water.
- 5. The method of claim 1, further comprising as a component a catalyst selected from the group consisting of: gel catalysts and gas forming catalysts, and mixtures thereof.
- 6. The method of claim 1, further comprising as components from 0.5 to 2.0 parts of a blow catalyst and from 0 to 0.3 parts of a gel catalyst.
- 7. The method of claim 1, wherein at least 5.0 parts by weight of the ester polyol comprises a hydrophilic polyester polyol made from an adipic acid and a polyethylene glycol.
- 8. The method of claim 1, further comprising a double cell-forming additive as a component.
- 9. The method of claim 1, further comprising an antimicrobial additive as a component.
- 10. The method of claim 1, wherein the caustic bath is formed as a solution containing sodium hydroxide.
- 11. The method of claim 1, wherein the treated foam is felted by compressing the foam to from one-third to one-eighth of its original thickness.
- 12. The method of claim 1, wherein the treated foam is felted by compressing the foam while heating the treated foam to a temperature of from 340 to 380° F. (171 to 193° C.).
- 13. The method of claim 1, wherein before felting, the hydrophilic ester polyurethane foam has pore sizes in the range of 70 to 130 pores per linear inch (27.6 to 51 pores per cm).
- 14. The method of claim 1, wherein the isocyanate index is 100 or less.
- 15. The method of claim 1, wherein the hydrophilic ester polyurethane foam has an instantaneous wet out.
- 16. A hydrophilic ester polyurethane foam made according to the method of claim 1.
Cross-Reference to Related Applications
[0001] This application is a continuation in part of U.S. patent application Ser. No. 10/074,606, filed Feb. 12, 2002. This application further claims priority from U.S. Provisional Application Serial No. 60/435,277, filed Dec. 23, 2002.
[0002] This invention relates to certain ester polyurethane foams that have been chemically modified and then felted (compressed under heat and pressure), following which the foams have unexpectedly improved liquid absorption and wicking. The foams may be incorporated into articles used to wipe and absorb liquids, such as household cleaning sponges and mop heads.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60435277 |
Dec 2002 |
US |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
10074606 |
Feb 2002 |
US |
Child |
10744052 |
Dec 2003 |
US |