Polyurethane foams prepared from mechanically frothed polyurethane dispersions

• US 6,271,276 B1
• Filed: 12/16/1999
• Issued: 08/07/2001
• Est. Priority Date: 12/29/1998
• Status: Expired due to Term

• Current Assignee: Dow Global Technologies LLC (Dow, Inc.)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Schrock, Alan K., Van Bellegem, Paulus C. J. M., Kennedy, James G., Tabor, Rick L., Gribble, Michael Y., Jakubowski, James J.
• Primary Examiner(s): Gorr, Rachel
• Assistant Examiner(s): Bagwell, M D
• Application Number:
  US09/464,113
• Time in Patent Office: 600 Days
• Field of Search: 521/67, 521/133, 521/159, 428/314.4, 428/304.4, 264/50, 264/48
• US Class Current: 521/133
• CPC Class Codes: C08G 18/0866 the dispersing or dispersed phase being an aqueous medium
• CPC Class Codes: C08G 18/12 using two or more compounds having active hydrogen in the first polymerisation step
• CPC Class Codes: C08G 18/283 Compounds containing ether groups, e.g. oxyalkylated monohydroxy compounds
• CPC Class Codes: C08G 18/3246 heterocyclic, the heteroatom being oxygen or nitrogen in the form of an amino group
• CPC Class Codes: C08J 2375/04 Polyurethanes
• CPC Class Codes: C08J 9/30 by mixing gases into liquid compositions or plastisols, e.g. frothing with air
• CPC Class Codes: D06N 2203/041 Polyacrylic
• CPC Class Codes: D06N 2203/042 Polyolefin (co)polymers
• CPC Class Codes: D06N 2203/047 Arromatic vinyl (co)polymers, e.g. styrene
• CPC Class Codes: D06N 2203/048 Polyvinylchloride (co)polymers
• CPC Class Codes: D06N 2203/068 Polyurethanes
• CPC Class Codes: D06N 2209/1685 Wear resistance
• CPC Class Codes: D06N 3/14 with polyurethanes
• CPC Class Codes: D06N 7/0073 the back coating or pre-coat being applied as an aqueous dispersion or latex
• CPC Class Codes: D06N 7/0086 characterised by the cushion backing, e.g. foamed polyurethane
• CPC Class Codes: Y10T 428/249976 Voids specified as closed

Abstract

The present invention is polyurethane dispersion composition that can be mechanically frothed to yield a foam that has good resiliency. Frothed foams of the present invention can be useful in cushioned flooring applications such as attached cushion broadloom, carpet tiles, carpet underlay, or vinyl flooring. Frothed foams of the present invention can also be useful as coatings for various textiles and for diapers.

Claims

1. A resilient polyurethane foam comprising a foam prepared by a process including the steps of (1) frothing an aqueous externally stabilized polyurethane dispersion;

(2) applying the froth to a substrate; and

(3) drying the froth into a foam, wherein;

a) the externally stabilized polyurethane dispersion is prepared by admixing water, a chain extender, an external anionic surfactant, and a polyurethane prepolymer under mixing conditions sufficient to prepare a stable dispersion;

b) the polyurethane is prepared from a formulation including a polyisocyanate and a polyol having a hydroxyl functionality of greater than about 2.2; and

c) the polyurethane foam has a resiliency of from about 5 to about 80 percent.

2. The polyurethane foam of claim 1 wherein the polyurethane foam has a resiliency of from about 10 to about 60 percent.

3. The polyurethane foam of claim 2 wherein the polyurethane foam has a resiliency of from about 15 to about 50 percent.

4. The polyurethane foam of claim 1 wherein the polyurethane is prepared from a formulation including a polyol having a hydroxyl functionality of from about 2.2 to about 5.0.

5. The polyurethane foam of claim 4 wherein the polyurethane is prepared from a formulation including a polyol having a hydroxyl functionality of from about 2.3 to about 4.0.

6. The polyurethane foam of claim 5 wherein the polyurethane is prepared from a formulation including a polyol having a hydroxyl functionality of from about 2.6 to about 3.5.

7. The polyurethane foam of claim 6 wherein the polyurethane is prepared from a formulation including a polyol having a hydroxyl functionality of from about 2.6 to about 3.5 and that polyol is only polyol included in the formulation.

8. The polyurethane foam of claim 1 wherein the polyurethane prepolymer is prepared using from a formulation which includes MDI as the only polyisocyanate.

9. A foam backed substrate comprising a substrate and adherent thereto a resilient polyurethane foam of claim 1.

10. The foam backed substrate of claim 9 wherein the substrate is cushioned flooring and the foam is a filled foam.

11. The foamed back cushioned flooring of claim 10 wherein the cushioned flooring is a carpet.

12. A method of making a resilient polyurethane foam adhered to a substrate comprising the steps of (1) frothing an aqueous externally stabilized fully reacted polyurethane dispersion in the presence of a foam stabilizer;

(2) applying the froth to a substrate, and (3) drying the froth into a foam, wherein;

a) the externally stabilized polyurethane dispersion is prepared by admixing water, a chain extender, an external anionic surfactant, and a polyurethane prepolymer under mixing conditions sufficient to prepare a stable dispersion;

b) the polyurethane is prepared from a formulation including a polyisocyanate and a polyol having a hydroxyl functionality of greater than about 2.2; and

c) the polyurethane foam has a resiliency of from about 5 to about 80 percent.

13. The method of claim 12 wherein the froth includes a filler.

14. The method of claim 13 wherein the substrate is cushioned flooring.

15. The method of claim 12 wherein step (3) includes exposing a surface of the froth to infra-red heat to promote formation of a smooth skin on the surface of the foam facing the heater, and further drying the froth at temperatures of from 50°

C. to 200°

C.

16. The method of claim 15 wherein the substrate is a carpet and wherein the foam has a resiliency of from about 15 to about 50 percent.

17. The method of claim 12 wherein the foam is resistant to yellowing.