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US 2011/0256331 A1Published application
Ultra-high iv polyester for extrusion blow molding and method for its production
AssigneeDak Americas LLC
InventorsHelen J. CODD, George F. ROLLEND, Norman W. LISSON
Life of this patent
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Abstract
An ultra-high IV polyester suitable for high melt strength end-uses, such as injection blow molding, pipe extrusion, profile extrusion, and extrusion blow molding, is provided, having IV of greater than 0.9; and a process for its production having high IV lift rate during SSP processing.
Claims24
A method for producing an ultra-high intrinsic viscosity (IV) polyester resin having a final IV (IVf) of at least 0.9 dL/g, comprising:
- solid-state polymerizing a polyester starting material having a starting IV (IVst) meeting the following relationship:
- 0.65 dL/g<IVst<0.9 dL/g;
- wherein the polyester starting material is a polyethylene terephthalate polymer, optionally containing one or more comonomers in amounts up to 30 mol %, wherein the polyester starting material has been prepared by melt polymerization up to the IVst with no more than 0.05 dL/g of IV lift due to solid-state polymerization, and wherein the polyester starting material is in solid form as a resin particle having been subjected to latent heat crystallization upon formation of the resin particle, and having a variation of IV of no more than 0.05 dL/g across any dimension of the resin particle.
Dependencies are inferred from the claim text.