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:
Jul. 24, 2001
Filed:
Jun. 01, 1999
Satoshi Nagai, Ibaraki, JP;
Osamu Kondo, Ibaraki, JP;
Shu Yoshida, Ibaraki, JP;
Makoto Sasaki, Ibaraki, JP;
Takashi Konishi, Ibaraki, JP;
Takayasu Fujimori, Ibaraki, JP;
Mitsubishi Gas Chemical Company, Inc., Tokyo, JP;
Abstract
Processes for producing an aromatic/aliphatic copolycarbonate which has excellent impact resistance, excellent heat resistance, a high Abbe's number, a low photoelastic coefficient, and an excellent color tone. The processes include those in which: an aromatic/aliphatic copolycarbonate having a nitrogen content of 9 ppm or lower is produced from an aliphatic dihydroxy compound having a nitrogen content of 10 ppm or lower; an aromatic/aliphatic copolycarbonate is produced from an aliphatic dihydroxy compound having an iron content of 1 ppm or lower; an aromatic/aliphatic copolycarbonate is produced from an aliphatic dihydroxy compound having a content of aldehyde groups and/or formyl groups of 100 ppm or lower; an aromatic/aliphatic copolycarbonate is produced by subjecting an aromatic dihydroxy compound and an aliphatic dihydroxy compound having a content of free chlorine of 5 ppm or lower to polycondensation with heating and melting; and an aromatic/aliphatic copolycarbonate is produced from an aliphatic dihydroxy compound which has a melt Hazen unit of 40 or smaller after having been maintained at 260° C. for 5 hours in the air.