| 摘要 |
A process for film production characterized by forming a film of a melt from a polyhydroxyalkanoic acid as a raw material, rapidly cooling the melt film to a temperature which is not higher than the temperature higher by 10°C than the glass transition temperature of the polyhydroxyalkanoic acid to thereby solidify it and prepare an amorphous film, and subjecting the amorphous film to cold stretching and then to a heat treatment under tension. The process enables a high-strength film to be obtained regardless of the molecular weight, composition (homopolymer or copolymer), and other properties of the PHA, which vary depending on the origin of the polymer, i.e., depending on whether the polymer is one produced by a wild-type strain of a PHA-producing microorganism, one produced by a recombinant strain, chemically synthesized one, etc. Also provided is a film which is stable at ordinary temperature, has high strength, and is capable of secondary processing.
|
