Improved clarity and adjustable shrinkage of shrink films using miscible polyester blends

摘要

A heat-shrinkable film is provided comprising a copolyester blend of: (a) about 1 to about 98.5 percent by weight of a PETG copolyester, (b) about 98.5 to about 1 percent by weight of a DEG modified PET copolyester having a b* value of less than 15, preferably less than 10, (c) about 0.5 to about 3 percent by weight of anti-blocking agent, and optionally, (d) about 5 to about percent by weight of a crystallizable polyester. Component (a) comprises 100 mol percent dicarboxylic acid residue component of at least 95 mol percent terephthalic acid residues and 100 mol percent diol residue component of about 65 to about 80 mol percent ethylene glycol residues and about 35 to about 20 mol percent 1,4-cyclohexanedimethanol residues. Component (b) comprises 100 mol percent dicarboxylic acid residue component, 100 mol percent diol residue component, catalyst residues and color control agent residues. The dicarboxylic acid residue component comprises at least 75 mol percent of terephthalic acid residues. The diol residue component comprises 10 to 50 mol percent diethylene glycol residue and 50 to 90 mol percent ethylene glycol residue. The catalyst residues comprise 20 to 100 ppm manganese, 50 to 300 ppm antimony, 0 to 100 ppm titanium and 40 to 150 ppm phosphorus, based on the weight of the copolyester. The color control agent residues comprises either (i) 40 to 100 ppm cobalt, (ii) 1.5 to 10 ppm of blue compounds of substituted 1,4-bis(2,6-dialylanilino) anthraquinones and 0.5 to 6 ppm of red compounds of anthraquinones and (iii) 0.5 to 10 ppm of 1-cyano-3H-dibenzÄf,ijÜ isoquinoline-2,7-diones, all ppm based on the weight of the copolyester.