Continuous formation of tubes of poly-4-hydroxybutyrate and copolymers thereof
US11040170B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 2018 |
| Grant date | Jun 22, 2021 |
| Priority date | — |
| Expiry date | Apr 23, 2039 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2367/00
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Methods have been discovered that make it possible to continuously extrude tubes of P4HB and copolymers thereof. These methods allow tubes of P4HB and copolymers thereof to be produced without radial deformation of the tubes despite the slow crystallization of the polymer and copolymers. The methods can produce tubes of P4HB and copolymers thereof with tightly defined outside and inside diameters which are required for medical application. These tubes are produced by radial expansion at temperatures above the melting temperature of P4HB and copolymers thereof, and using low tube cooling temperatures and prolonged cooling times. The tubes made from P4HB and copolymers thereof are flexible, and can be prepared with high elongation to break values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.