Process for making PEN/PET blends and transparent articles therefrom
US5902539A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 6, 1996 |
| Grant date | May 11, 1999 |
| Priority date | — |
| Expiry date | Dec 6, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/917
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Process for controlling the rate of change of intrinsic viscosity and transesterification during solid stating of a polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) blend, with an effective amount of an ethylene glycol compound. The process enables the production of a copolymer based on predefined initial and final IV's and final transesterification level, by varying the solid-stating time and/or effective amount of ethylene glycol. In one embodiment, a relatively greater amount of post-consumer PET (e.g., 70%) having an IV of on the order of 0.72-0.73, is incorporated in the blend to provide a final IV on the order of 0.80-0.85, and a moderate, controlled level of transesterification; the blend is used to injection mold a sleeve layer of a preform. In another embodiment, a substantially transparent neck finish for a preform is made from a PEN/PET blend having an amount of ethylene glycol which enables substantial transesterification, without excessive increase in IV.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.