Easily dyeable polyester film and preparation thereof
US6258921A · kind A · utility
Inventors
Key dates
| Filing date | Dec 11, 1997 |
| Grant date | Jul 10, 2001 |
| Priority date | — |
| Expiry date | Dec 11, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/13
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A double-axis elongated polyester film for dyeing which simultaneously satisfies following formulas: EQU 3.295.ltoreq.N.sub.MD +N.sub.TD.ltoreq.3.340 (1) EQU Benzene plane orientation.ltoreq.0.740 (2) EQU Crystallinity (%).ltoreq.54 (3) EQU 3.ltoreq.Thermal shrinkage in machine direction(%).ltoreq.7 (4) EQU 0.ltoreq.Thermal shrinkage in transverse direction(%).ltoreq.3 (5) The polyester film is prepared by melt-extruding polyester chips and cooling the extrudate in a cooling drum to prepare a non-crystalline sheet; elongating said sheet at a temperature between 80 and 100.degree. C. which is higher than glass transition temperature (Tg) to make 3.0 to 3.6 folds of length in machine direction to obtain single-axis elongated film; further elongating the film to 3.0-4.2 folds of length in transverse direction at 120-140.degree. C.; thermally treating the obtained film in Tenter's thermal treatment zone at 210-240.degree. C. with at least 5 stages; and rolling the double-axis elongated film obtained by releasing 0.01-10% of the film in machine and/or transverse direction. The film obtained above must satisfy both formulas (1) and (2).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.