US 5,852,156 AGranted

Polycarbonate composition

AssigneeAsahi Kasei Kogyo Kabushiki Kaisha

InventorsHiroshi Hachiya, Kyosuke Komiya, Tetsuo Hamada

Life of this patent

Estimating the term…

Loading patent…

Abstract

A polycarbonate composition comprises (a) a substantially chlorine-atom free, aromatic dihydroxy compound/carbonic diester transesterification polycarbonate, and the following components (b), (c) and (d) in specifically, extremely limited amounts, wherein component (b) is at least one metal selected from an alkali metal and an alkaline earth metal, component (c) is an aromatic monohydroxy compound, and component (d) is at least one member selected from an oligomer having a weight average molecular weight of 1,000 or less and a residual monomer. This polycarbonate composition is substantially free from occurrence of crazing, even when it experiences moist heat, and especially even when it has been recycled. Further, when this polycarbonate composition is continuously injection-molded, not only can the molding be carried out with less necessity of interruption for mold cleaning, but also even when the continuous molding is interrupted for mold cleaning or for other reasons and then restarted, occurrence of unfavorable phenomena (such as deposition of black spots, i.e., carbonized material waste, and development of brown streaks, uneven color and the like) can be effectively suppressed.

Claims18

Dependent claims

A polycarbonate composition comprising:

(a) a substantially chlorine-atom free, aromatic dihydroxy compound/carbonic diester transesterification polycarbonate, wherein said polycarbonate (a) satisfies the following two requirements:
(1) the chlorine atom content of the polycarbonate (a) is 0.5 ppm or less in terms of the chlorine ion content as measured by potentiometric titration using an aqueous 1/500N silver nitrate solution or by ion chromatography and (2) the chlorine atom content of the polycarbonate (a) is 10 ppm or less as measured by the combustion method,
(b) at least one metal selected from the group consisting of an alkali metal and an alkaline earth metal,
(c) an aromatic monohydroxy compound, and
(d) at least one member selected from the group consisting of:
an aromatic dihydroxy compound/carbonic diester transesterification oligomer having a weight average molecular weight of 1,000 or less;
and
a residual monomer selected from the group consisting of said aromatic dihydroxy compound, said carbonic diester and a mixture thereof,
said components (b), (c) and (d) being, respectively, present in amounts of not more than 800 ppb by weight, not more than 200 ppm by weight, and not more than T.sub.2 % by weight, each based on the total weight of said components (a), (b), (c) and (d), wherein T.sub.2 is defined by the following formula:
T.sub.2 =1,520,000.times.(weight average molecular weight of said polycarbonate).sup.-1.44.

7 more elements

Dependencies are inferred from the claim text.