| 摘要 |
Disclosed are branched polyester compositions having an I.V. of at least about 0.7 dl/g and a melt viscosity sufficiently high to permit foaming during extrusion or molding operations. These branched polyesters are readily foamable with a wide range of foaming agents to provide low density shaped articles, films, and sheets. The branched polyesters comprise about 80 to about 99.9 wt % of a polyester and about 0.1 to about 20 wt % of an ethylene copolymer containing repeat units of ethylene and of a monomer selected from the group comprising acrylic acid, methacrylic acid, alkyl acrylate, alkyl methacrylate and vinyl alcohol. The polyester comprises repeat units from about 75 to 100 mol % of a dibasic acid having from about 6 to about 40 carbon atoms and 0 to about 25 mol % of a modifying dibasic acid and repeat units from about 75 to 100 mol % of a glycol having from about 2 to about 10 carbon atoms, 0 to about 25 mol % of a modifying glycol and 0 to about 25 mol % of a modifying compound selected from the group comprising amino alcohols, diamines and lactams.
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