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US 6,187,832 B1Granted
Process for making flexible polyurethane foams
AssigneeImperial Chemical Industries PLC
InventorJan Willem Leenslag
Life of this patent
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Abstract
Process for preparing a flexible polyurethane foam by reacting a polyisocyanate and two different polyols under foam forming conditions so as to prepare a rigid foam, by crushing the rigid foam so obtained and by subjecting the flexible foam so obtained to a heat treatment. Flexible foams are obtained which do not show a major glass transition temperature between −100° C. and +25° C.
Claims23
A process for preparing a flexible polyurethane foam comprising:
- reacting a polyisocyanate with a first isocyanate-reactive compound, a second isocyanate-reactive compound, and water to form a rigid polyurethane foam;
- crushing said rigid polyurethane foam to form a flexible polyurethane foam;
- and
- heating said flexible polyurethane foam to a temperature between 70° C. and 200° C. for a period of time between 0.5 minute and 8 hours;
- wherein said crushed polyurethane foam has a ratio E′−100° C./E′25° C. of 1.3 to 15.0.
2 more elements
A process for preparing a flexible polyurethane foam comprising:
- reacting a polyisocyanate with a first polyol, a second polyol, and water to form a rigid polyurethane foam;
- crushing said rigid polyurethane foam to form a flexible polyurethane foam;
- and
- heating said flexible polyurethane foam to a temperature between 70° C. and 200° C. for a period of time between 0.5 minute and 8 hours;
- wherein said crushed polyurethane foam has a ratio E′−100° C./E′25° C. of 1.3 to 15.0;
- and wherein
- said first polyol is present in an amount of 2-20 parts by weight and has a hydroxyl number of at least 150 mg KOH/g and an average nominal hydroxyl functionality of from 2 to 8;
- said second polyol is present in an amount of 5-35 parts by weight and has a hydroxyl number of from 10 to less than 150 mg KOH/g and an average nominal hydroxyl functionality of from 2 to 6;
- said water is present in an amount of 1-17 parts by weight;
- and
- wherein said parts by weight are relative to the total combined weights of said polyisocyanate, said first polyol, said second polyol, and said water;
- and
- wherein the weight ratio of said first polyol to said second polyol is from 0.1:1 to 4:1.
10 more elements
Dependencies are inferred from the claim text.