Production of urethane foams and laminates thereof

• US 3,933,548 A
• Filed: 08/19/1974
• Issued: 01/20/1976
• Est. Priority Date: 08/19/1974
• Status: Expired due to Term

• Current Assignee: Polyvinyl/Permuthan Company
• Original Assignee: Beatrice Foods Company (Conagra Brands, Inc.)
• Inventors: Knisely, Charles K., Anderson, Harry M. Jr.
• Primary Examiner(s): Whitby, Edward G.
• Application Number:
  US05/498,584
• Time in Patent Office: 519 Days
• Field of Search: 117/161 KP, 117/DIG. 3, 264/DIG. 5, 260/2.5 AE, 260/2.5 AY, 156/79, 156/78, 156/246, 428/320, 428/322, 428/423
• US Class Current: 156/78
• CPC Class Codes: B32B 2038/0084 Foaming
• CPC Class Codes: B32B 2266/0278 Polyurethane
• CPC Class Codes: B32B 2307/536 Hardness
• CPC Class Codes: B32B 5/20 foamed in situ
• CPC Class Codes: C08J 2201/022 premixing or pre-blending a part of the components of a foamable composition, e.g. premixing the polyol with the blowing agent, surfactant and catalyst and only adding the isocyanate at the time of foaming
• CPC Class Codes: C08J 2203/02 CO2-releasing, e.g. NaHCO3 and citric acid
• CPC Class Codes: C08J 2375/04 Polyurethanes
• CPC Class Codes: C08J 9/08 developing carbon dioxide
• CPC Class Codes: Y10S 264/05 Use of one or more blowing agents together
• CPC Class Codes: Y10S 428/904 Artificial leather
• CPC Class Codes: Y10T 428/249953 Composite having voids in a component [e.g., porous, cellular, etc.]

Abstract

Thin flexible urethane foam film layers are produced by spreading a layer of polyurethane reactants over a carrier sheet at a uniform layer thickness. The polyurethane reactants consist essentially of an isocyanate and a hydroxyl terminated polyol having an inorganic carbon dioxide producing blowing agent incorporated therein and being free of water. The unconfined film layer is then heated to a temperature in the range of from 260°F to 390°F to cause gellation and release of the carbon dioxide in the mixture with final formation of a uniform thickness flexible polyurethane foam product.

Claims

1. A method of forming a flexible polyurethane foam layer having uniform controlled film layer thickness,

said method comprising,

spreading a layer of a polyurethane reactants containing mixture over a carrier surface in a uniform layer thickness,

said polyurethane reactants consisting essentially of an isocyanate and a hydroxyl terminated polyol having from 1 to 9% by weight thereof of an inorganic carbon dioxide producing blowing agent incorporated therein,

and heating said layer to a temperature in the range of from 260°

F to 390°

F to cause release of carbon dioxide in said mixture and formation of polyurethane foam in a uniform thickness final product.

2. A method in accordance with the method of claim 1 wherein said inorganic blowing agent is sodium bicarbonate and said foam thickness is in the range of from 0.006 to 0.l40 inch.

3. A method in accordance with claim 2 wherein said film of urethane reactants is continuously spread over a continuously moving carrier sheet and said heating is carried out in an oven through which said sheet passes.

4. A method in accordance with the method of claim 3 wherein said oven acts to bring said mixture to a gel state while causing evolution of carbon dioxide to foam said gel,

and thereafter curing said foam at a uniform thickness.

5. A method in accordance with the method of claim 4 and further comprising continuously passing a supporting layer web into contact with a surface of said gelled layer while it is tacky to form a laminate therewith prior to final cure of said polyurethane foam.

6. A method in accordance with the method of claim 1 wherein said urethane reactants are spread over a surfacing web and adhered thereto.

7. A method in accordance with the method of claim 6 and further comprising heating said foam layer to a gelled state while causing evolution of carbon dioxide,

passing a supporting layer web into contact with a surface of said gelled foam layer to form a laminate therewith, and heating to cure said polyurethane foam in a composite laminate.

8. A method in accordance with the method of claim 7 wherein said foam layer thickness is in the range of from 0.010 to 0.025 inch.

9. In a method of forming polyurethane foam layers having hardness values of 50 Shore A to 80 Shore A from polyurethane reactants containing mixtures comprising an isocyanate and a polyol,

the improvement comprising,

incorporating in the reactants from 1 to 9% by weight of powdered sodium bicarbonate nonreactive with the isocyanate and capable of releasing carbon dioxide at temperatures in the range of from 260°

F to 390°

F,

positioning a film of from 0.003 inch to 0.07 inch of said mixture on a carrier layer in a uniform thickness,

and heating said film to form a urethane foam having a uniform thickness of from 0.006 to 0.140 inch.

10. A method in accordance with the improvement of claim 9 wherein said polyurethane reactants comprise a first component containing an isocyanate and a second component containing a polyol and said sodium bicarbonate.

11. A method in accordance with the method of claim 10 and further comprising said isocyanate containing component further comprising benzoyl chloride in an amount to inhibit a polyurethane reaction and give a pot life of the two components when mixed of at least 3 hours at 72°

F.