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:
Nov. 28, 1989
Filed:
Apr. 20, 1987
Eugene R Moore, Midland, MI (US);
Brian D Dalke, Midland, MI (US);
Michael T Malanga, Midland, MI (US);
Gary M Poindexter, Midland, MI (US);
The Dow Chemical Company, Midland, MI (US);
Abstract
The specification discloses a monovinylidene aromatic polymer having a molecular weight of at least 50,000 and an extremely narrow molecular weight distribution of less than 1.5, preferably with at least 80% by weight of the polymer having a molecular weight within plus or minus 30% of the weight average molecular weight. This polymer is produced through anionic polymerization of a pure feed stock which is first cooled to a temperature at which an anionic initiator preferentially reacts with impurities present in the feed stock and initiates the polymerization reaction but does not substantially propagate styrene polymerization. The initiator is uniformly dispersed into the feed stock while maintaining it at the lower temperature and the feed stock temperature is subsequently increased to a temperature at which polymerization of the sytrene proceeds normally. The resulting polymer is especially well adapted to injection molding in that exceptional strength properties are achieved in combination with good processability, e.g., melt flow rate.