Polycarbodiimide modification of polyesters for extrusion applications
US4071503A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 19, 1976 |
| Grant date | Jan 31, 1978 |
| Priority date | — |
| Expiry date | Aug 19, 1996 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L67/02
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
There is disclosed a process for preparing polycarbodiimide modified thermoplastic polyesters having unique rheological properties which include increased intrinsic viscosity and melt strength. These polycarbodiimide modified thermoplastic polyesters are prepared by reacting the carboxyl end groups of thermoplastic saturated polyesters which are in a molten state with the polycarbodiimide groups of at least one polycarbodiimide such as poly (4,4'-diphenyl-methane carbodiimide) which both (a) is derived from at least one aromatic diisocyanate which is either unsubstituted or contains up to one methyl substituent on each aromatic ring, and (b) contains at least three carbodiimide units per polycarbodiimide molecule. The resulting polycarbodiimide modified thermoplastic polyester has improved melt strength and intrinsic viscosity and a decreased number of carboxylic acid end groups. These improved melt strength polyesters also have improved die swell and shear sensitivity characteristics and are generally useful in extrusion applications such as blow molding.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.