Process for producing transparent and heat-resistant polyester containers
US5183623A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 4, 1991 |
| Grant date | Feb 2, 1993 |
| Priority date | — |
| Expiry date | Oct 4, 2011 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2995/0041
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A process for producing a transparent and heat-resistant container includes forming a sheet from a melt of a polyester resin having at least 80 mole % ester units derived from 1,3-propanediol and terephthalic acid or an ester-forming derivative thereof. The formed sheet is quenched and solidified so as to have relatively low crystallinity (i.e., less than 50%). The solidified low crystallinity film is then aged and shaped by thermoforming to obtain a container having relatively high crystallinity (i.e., greater than 50%, and preferably greater than 80%). The aging step is most preferably conducted at a temperature which satisfies the relationship represented by the following equation (1): EQU Ta.ltoreq.Tcc wherein Ta is the aging temperature (.degree.C.), and Tcc is the cold crystallization temperature (.degree.C.) as determined by differential thermal analysis at a rate of temperature increase of 10.degree. C./min. Moreover, the aging step is practiced such that the aged sheet satisifies the relationship represented by the following equation (2): EQU (.DELTA.Hcc)a.gtoreq.5.0 (J/g) wherein (.DELTA.Hcc)a is the heat of cold crystallization (J/g) of the aged sheet as determined by di…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.