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Preparation of carbodiimide-containing polyisocyanates

  • US 4,143,063 A
  • Filed: 04/10/1978
  • Issued: 03/06/1979
  • Est. Priority Date: 01/31/1977
  • Status: Expired due to Term
First Claim
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1. A process for preparing a carbodiimide-containing organic polyisocyanate said process comprising:

  • heating an organic polyisocyanate to a temperature in the range of about 70°

    C. to about 200°

    C. in the presence of a catalytic amount of a polymer characterized in that from 0.1 percent to 100 percent of the recurring units have the formula ##STR14## wherein R1 and R2 are hydrocarbyl free from substituents reactive with isocyanate groups, R3 is selected from the class consisting of hydrogen, chloro and methyl, R4 is selected from the class consisting of hydrogen and methyl, and n is an integer from 0 to 1 and the remainder of the recurring units in said polymer have the formula ##STR15## wherein R4 and R3 are as above defined;

    continuing said heating until the desired proportion of carbodiimide-formation has occurred; and

    stopping said reaction by separating the solid catalyst from the carbodiimide containing organic polyisocyanate.

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