Preparation process of the formed product of L-lactic acid base polymer
US6290896A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 1995 |
| Grant date | Sep 18, 2001 |
| Priority date | — |
| Expiry date | May 18, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2367/04
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A formed product which has a thickness of 0.1.about.2 mm and a haze of 5%/2 mm or less and is degraded with ease in the natural environment is obtained by holding a transparent L-lactic acid base polymer sheet having an L-lactic acid proportion of 75% or more and a thickness of 0.2.about.2 mm under conditions where: PA1 (1) a holding temperature is in the range of 55.about.90.degree. C., PA1 (2) a holding time m.sub.1 (min) satisfies the formula: EQU log.sub.10 m.sub.1 <-0.083 T.sub.1 +7.66, forming said sheet by adhering to the internal surface of a mold through vacuum suction, compressed air pressure or vacuum/air pressure under a condition where: PA1 (3) a mold temperature T.sub.2 is set in the range of from the glass transition temperature Tg of the L-lactic acid base polymer to the holding temperature T.sub.1, and taking out the formed product from the mold after reducing an internal temperature of the mold to less than Tg.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.