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. 20, 1997
Filed:
Oct. 27, 1995
Hideyuki Hongo, Kanagawa, JP;
Akio Yamaguchi, Kanagawa, JP;
Yoji Hori, Kanagawa, JP;
Toshimitsu Hagiwara, Kanagawa, JP;
Yoko Takahashi, Kanagawa, JP;
Abstract
The block copolymer of polyesters and polycarbonates comprises at least one of each of the constituting units of (I) and (II) having the general formulae: ##STR1## where the sign * indicates an asymmetric carbon atom; R.sub.1, R.sup.2, R.sup.3 and R.sup.4 are either a hydrogen atom or a methyl group; m and n are respective a natural numbers ranging from 300 to 5000: The block copolymer is obtained by successive ring-opening and copolymerization of optically active .beta.-butyrolactones and cyclic carbonates in the presence of a catalyst. The block polymer obtained has high molecular weight and high melting temperature, and can thus be used as a high strength material for practical use and which has bio-degradable and hydrolyzable nature.