PROCESS FOR PROFILE EXTRUSION OF A POLYESTER

摘要

In a process for producing a profile by profile extrusion, a melt of a polyester composition is extruded through a die to form a profile. The processability of the polyester composition is improved by the addition of a branching agent, which provides increased melt strength and increased high shear thinning. The polyester composition has an inherent viscosity of at least 0.65 dl/g. The diacid component of the polyester composition has from 100 to 98.0 mole percent of residues of a primary acid selected from terephthalic acid, naphthalenedicarboxylic acid, isophthalic acid and mixtures therof. The glycol component of the polyester composition has from 100 to 98.0 mole percent of residues of a primary glycol selected from ethylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, neopentyl glycol, and mixtures thereof. The polyester composition has from 0.05 to 2.0 mole percent of residues of the branching agent selected from an acidic branching agent with a tri-functional or greater monomer, an alcoholic branching agent with a tri-functional or greater monomer, and mixtures thereof. The branching agent is present as part of either the diacid component or glycol component depending on whether the functionality is acidic or alcoholic, respectively.