Renewable polyester compositions having a low density
US9518181B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 2015 |
| Grant date | Dec 13, 2016 |
| Priority date | — |
| Expiry date | Apr 24, 2035 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L2207/04
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A thermoplastic composition that contains a rigid renewable polyester and has a voided structure and low density is provided. To achieve such a structure, the renewable polyester is blended with a polymeric toughening additive to form a precursor material in which the toughening additive can be dispersed as discrete physical domains within a continuous matrix of the renewable polyester. The precursor material is thereafter stretched or drawn at a temperature below the glass transition temperature of the polyester (i.e., “cold drawn”). This creates a network of voids located adjacent to the discrete domains, which as a result of their proximal location, can form a bridge between the boundaries of the voids and act as internal structural “hinges” that help stabilize the network and increase its ability to dissipate energy. The present inventors have also discovered that the voids can be distributed in a substantially homogeneous fashion throughout the composition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.