US 4,788,224 AGranted

Two stage process for the production of molded articles

AssigneeBayer Aktiengesellschaft

InventorsHanns P. Muller, Walter Uerdingen, Heinrich Heine

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Abstract

Molded articles are produced in a two-stage process. In the first stage, an organic polyisocyanate is reacted with an organic compound containing at least two epoxide groups (NCO: epoxide equivalent ratio of 1.2:1 to 500:1) in the presence of a tertiary amine catalyst. This reaction is stopped when no more than 65% of the isocyanate groups have reacted by adding an alkylating sulfonic acid alkyl ester of methyl iodide and/or of dimethyl sulfate in an amount equivalent to the amount of tertiary amine catalyst present. A latent catalyst capable of being activated by heat is subsequently added to the intermediate product and the resultant mixture is heated in a mold to complete the crosslinking of the intermediate product and to form the molded article.

Claims8

Dependent claims

A two-stage process for the production of molded articles comprising

(a) reacting
(1) at least one organic polyisocyanate with
(2) at least one organic compound containing at least two epoxide groups
in quantities such that the ratio of isocyanate groups to epoxide groups is from 1.2:1 to 500:1, in the presence of
(3) a tertiary amine catalyst
to form an intermediate product containing oxazolidinone and isocyanurate groups,
(b) stopping reaction (a) after no more than 65% of the isocyanate groups present in polyisocyanate (1) have reacted by adding an alkylating sulfonic acid alkyl ester, methyl iodide and/or dimethyl sulfate in a quantity which is at least equivalent to the quantity of tertiary amine (3) present,
(c) adding at least one latent catalyst capable of being activated by heat to the mixture of (b),
(d) supplying the mixture of (c) to a mold, and
(e) heating to complete the crosslinking of the intermediate product.

7 more elements

Dependencies are inferred from the claim text.