The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 08, 2001
Filed:
Feb. 09, 1999
Steinar Pedersen, Skein, NO;
Arvid Berge, Trondheim, NO;
Harald Jacobsen, Stathelle, NO;
Kari-Anne Leth-Olsen, Trondheim, NO;
Bård Sæthre, Porsgrunn, NO;
John Ugelstad , late of Trondheim, NO;
Norsk Hydro ASA, Oslo, NO;
Abstract
A procedure for the production of PVC particles with a narrow size distribution in the range 10-50 &mgr;m, preferably 10-30 &mgr;m, in which, in a first stage, a vinyl monomer or a mixture of monomers is polymerised to form a polymer/oligomer seed particle in the range 1-10 &mgr;m. In a second stage, another vinyl monomer or mixture of monomers is swelled into the polymer/oligomer seed particles and polymerisation takes place in such a way that they grow into polymer particles of the desired size. It is preferable to use aromatic vinyl monomers or acrylates as the monomer in the seed particles. The seed particles in the first stage can be produced in a two-stage swelling process or by dispersion polymerisation.