Graft copolymers and blends thereof with polyolefins
US4957974A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 1, 1989 |
| Grant date | Sep 18, 1990 |
| Priority date | — |
| Expiry date | Mar 1, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L2205/08
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A novel graft copolymer capable of imparting to a polyolefin when blended therewith high tensile modulus and high sag resistance without increasing melt viscosity, and a method of making the same. The graft copolymer is a polyolefin having a relatively high weight-average molecular weight methacrylate polymer grafted thereto. The graft copolymer is formed by dissolving or swelling a non-polar polyolefin in an inert hydrocarbon solvent, heating to dissolve the polyolefin, and while stirring the mixture, adding a methacrylate monomer, together with an initiator to produce a constant, low concentration of radicals, to form a graft copolymer with a high molecular weight polymer chain covalently bonded or grafted to the polyolefin backbone. The graft copolymer can be separated from the solvent, isolated by volatilizing the solvent, for example in a devolatilizing extruder, and extruded into a desired shape such as a sheet, tube or the like. This graft copolymer can be blended with a polyolefin matrix. The blend exhibits improved physical properties in the melt, upon cooling, and in the solid state, and is useful in cast and oriented films, solid extruded rod and profile, foamed rod, pro…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.