Method of producing a polyurethane foam molded article

• US 20060134398A1
• Filed: 12/14/2005
• Published: 06/22/2006
• Est. Priority Date: 12/17/2004
• Status: Active Grant

• Current Assignee: Bayer Materialscience AG (Covestro AG)
• Original Assignee: Bayer Materialscience AG (Covestro AG)
• Inventors: Nakamura, Masafumi, Maeda, Hitoshi, Suzuki, Masaru
• Granted Patent: US 7,540,985 B2
• Time in Patent Office: Days
• US Class Current: 428/310.500
• CPC Class Codes: B29C 44/0461 by having different chemical compositions in different places, e.g. having different concentrations of foaming agent, feeding one composition after the other
• CPC Class Codes: C08G 18/7664 containing alkylene polyphenyl groups
• CPC Class Codes: C08G 18/797 containing carbodiimide and/or uretone-imine groups
• CPC Class Codes: C08G 2110/0033 having integral skins
• CPC Class Codes: Y10T 428/249961 With gradual property change within a component

Abstract

A method of producing a polyurethane molded article is provided, in which one molding machine which can provide distinctly polyisocyanate component(s) and two kinds of polyol components is used, and prior to completion of the feed of a first polyurethane mixture liquid containing a polyisocyanate and a polyol component without a blowing agent into a mold, a second polyurethane mixture liquid containing a polyisocyanate and a second polyol component with a blowing agent is fed into the mold. The method produces, in a single stage, a polyurethane foam molded article having the skin or high density portion selectively formed on portions of the molded article actually requiring them, where the proportions of the skin and the high density portion and the foamed core can be varied freely.

Claims

1. A method of producing a polyurethane molded article from

(a) one or two polyisocyanate components, and

(b) two polyol components,

the method comprising:

providing a molding machine which can feed distinctly the polyisocyanate component(s) and two polyol components;

feeding a first polyurethane mixture liquid comprising a polyisocyanate component and a polyol component without a blowing agent into a mold with the molding machine; and

for at least 0.1 seconds prior to completion of feeding the first polyurethane mixture liquid,

feeding a second polyurethane mixture liquid comprising a polyisocyanate component and a polyol component with the blowing agent into the mold.

2. The method of producing a polyurethane molded article according to claim 1, wherein the quantity of the first polyurethane mixture liquid, to be fed before the feed of the second polyurethane mixture liquid, is at least 10 weight % of the total of the first polyurethane mixture liquid and the second polyurethane mixture liquid.

3. The method of producing a polyurethane molded article according to claim 1, wherein the first polyurethane mixture liquid is fed after the feed of the second polyurethane mixture liquid.

4. The method of producing a polyurethane molded article according to claim 3, wherein the quantity of the first polyurethane mixture liquid, to be fed after the completion of the feed of the second polyurethane mixture liquid, is at least 1.0 weight % of the total of the first polyurethane mixture liquid and the second polyurethane mixture liquid.

5. The method of producing a polyurethane molded article according to claim 1, wherein the blowing agent is at least one chosen from carbon dioxide, hydrocarbons, fluorinated hydrocarbons and water.

6. A polyurethane molded article, produced by the method according to claim 1, having both a high density part and a low density part, wherein the high density part has a density of at least 0.8 g/cm³ and covers at least 50% of the whole surface of the molded article.

7. A method of producing a polyurethane molded article from at least one polyisocyanate component and two polyol components, said method comprising:

feeding into a mold from a molding machine, a first polyurethane mixture liquid comprising a polyisocyanate and a first polyol component without a blowing agent, and for at least 0.1 seconds prior to completion of feeding the first polyurethane mixture liquid;

feeding into the mold from a molding machine, a second polyurethane mixture liquid comprising a polyisocyanate and a second polyol component with the blowing agent; and

curing the polyurethane molded article.