Binder resin, process for its manufacture and composition containing it
US6121364A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 13, 1998 |
| Grant date | Sep 19, 2000 |
| Priority date | — |
| Expiry date | Apr 13, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G9/08728
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A polymeric material comprising at least first and second polymer parts, which first part has a number average molecular weight higher than that of the second part and which first and second polymer parts each comprise a respective polymer part derived from at least one ethylenically unsaturated monomer, is prepared by a process which comprises the steps of (1) preparing, by aqueous suspension polymerisation the first, higher molecular weight polymer part in the presence of a free radical initiator, but in the absence of a chain transfer agent to form a suspension of the first, higher molecular weight part and thereafter (2) preparing by aqueous suspension polymerisation the second, lower molecular weight part, which preparation step (2) is carried out in the presence of the suspension of the first, higher molecular weight part, a free radical initiator and a catalytic chain transfer agent (CCTA). Step (2) may be continued to provide, additionally, a third polymer of a molecular weight intermediate that of the first and second polymers. A polymeric material thus obtainable has a PDi of at least 5 and a skewed molecular weight distribution in which the first-third polymers are prese…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.