IP Library › Granted Patent US 12668010
Granted Patent B2
US 12668010 · App. 18/000,453 · Granted Jun 30, 2026

Method for producing polymeric molded product

Inventors: Akira Maehara (Niigata, JP); Tadahisa Iwata (Tokyo, JP); Taku Omura (Tokyo, JP); Taizo Kabe (Sayo-gun, JP)
Assignees: Mitsubishi Gas Chemical Company, Inc.; The University of Tokyo
B29C48/022B29C48/78B29C48/92B29K2067/04B29K2995/006D01F6/84
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Quick Facts
Patent No.
US 12668010
App. No.
18/000,453
Granted
Jun 30, 2026
Kind
B2
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.

Claims (10)

1 . 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.

2 . The method according to claim 1 , further comprising:

cooling the melted polymer in air, in a temperature range where some of the lamellar crystals undergo melting and flowing, and the other balance lamellar crystals remain unmelted.

3 . The method according to claim 1 , wherein the melt-molding is molding through melt extrusion.

4 . The method according to claim 1 , wherein the melt-molding is molding through melt extrusion spinning.

5 . The method according to claim 1 , wherein the melt-molding is performed once.

6 . The method according to claim 1 , wherein the residual ratio of the molecular weight of the polymer after melt-molding is at least 93%.