US 4,904,746 A · Preparation of linear polyester-polyepoxide reaction products via reactive concentrate

Abstract

Branched polyester compositions having high melt viscosities, especially under conditions of low shear, are prepared in a two-step method. The first step is the reaction of a linear polyester, polycarbonate or polyester-polycarbonate containing free carboxylic acid groups with a polyfunctional epoxyalkyl compound such as triglycidyl isocyanurate to form a reactive concentrate. The second step is the reaction of said reactive concentrate with a polyester, such as poly(ethylene terephthalate) or poly(butylene terephthalate), containing a measurable proportion of carboxylic acid end groups. By this two-step method, it is possible to use less epoxy compound for a given melt viscosity level than is the case when the epoxy compound is directly blended with the polyester.

Claims19

Dependent claims

A method for preparing a branched polymer which comprises the steps of:

(I) forming a reactive concentrate by effecting reaction between the constituents of a mixture consisting essentially of (A) at least one poly(O- or N-epoxyalkyl-substituted) cyclic amide, imide or imidate with (B) at least one linear polymer having substantial proportions of at least one of ester and carbonate structural units, a number average molecular weight of at least about 4000 and a measurable proportion of free carboxylic acid groups, and
(II) melt blending said concentrate with (C) at least one linear polyester having a substantial proportion of free carboxylic acid groups;
the proportion of reagent A employed in step I being at least about 3 parts by weight per 100 parts of reagent B, and about 0.1-3.0 parts per 100 parts of the total of reagents B and C.

Dependencies are inferred from the claim text.

Preparation of linear polyester-polyepoxide reaction products via reactive concentrate

Life of this patent

Preparation of linear polyester-polyepoxide reaction products via reactive concentrate

Life of this patent

Abstract

Claims19