Improved modified pet polymers and copolymers suitable for blow molding.

摘要

There is disclosed an improved modified polymer suitable for use in making hollow containers by conventional extrusion blow molding. It is a specific type of end-capped and branched polyethylene terephthalate polymer or copolymer. In the improvement, the end-cap comprises the reacted component of a difunctional acid or alkali metal salt of a difunctional acid having the formula:
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wherein: X has a valency of 6 and is selected from sulfur, selenium and tellurium; M is an alkali metal or hydrogen; and Y is hydrogen or an aliphatic group containing 1 to 18 carbon atoms.

The preferred difunctional acid is m-sulfobenzoic acid. The product typically contains few large gels having diameters greater than 0.1mm.