Method for producing polymeric molded product
AssigneesMitsubishi Gas Chemical Company, Inc., The University of Tokyo
InventorsAkira Maehara, Tadahisa Iwata, Taku Omura, Taizo Kabe
Life of this patent
Estimating the term…
Abstract
An object of the present invention is to provide a method for producing a polymeric molded product, which does not undergo a considerable molecular weight reduction during melt-molding, even in a polymer may easily lose its molecular weight when it is in a melted state. The present invention provides a method for producing a polymeric molded product, which comprises melt-molding a polymer comprising lamellar crystals that are different in lamella thickness, in a temperature range where some of the lamellar crystals undergo melting and flowing, and the other balance lamellar crystals remain unmelted.
Claims6
A method for producing a polymeric molded product, the method comprising:
- melt-molding a polymer comprising lamellar crystals that are different in lamella thickness, in a temperature range where some of the lamellar crystals undergo melting and flowing, and the other balance lamellar crystals remain unmelted,
- wherein the temperature range is from 113.9° C. to 140.9° C., which is higher than an outflow onset temperature determined in accordance with a flow tester temperature raising method and lower than an extrapolated melting offset temperature, and wherein a residual ratio of a molecular weight of the polymer after melt-molding is more than 86%, and
- wherein the polymer is a copolymer comprising 3-hydroxybutyric acid and 4-hydroxybutyric acid as monomer units, and a proportion of the 4-hydroxybutyric acid is from 5 mol % to 40 mol %, and a weight average molecular weight of the polymer is 500.000 or greater.
Dependencies are inferred from the claim text.