Daicel Chemical Industries, Ltd.

Kenichi Sasaki

Tatsuya Kanno

Ikuo Takahashi

Yutaka Fukuda

Akihiro Izuka

Takeshi Horikawa

Tsuyoshi Sei

Tsuyoshi Habe

Tsunehisa Katsuki

Yoshiro Iguchi

A new aromatic polycarbonate is obtained from (1) 2,2-bis(4-hydroxy-3-isopropylphenyl)propane, (2) 2,2-bis(4-hydroxyphenyl)propane and 2,2-bis(4-hydroxy-3-isopropylphenyl) propane or (3) 4,4'-dihydroxy-2,2,2-triphenylethane and 2,2-bis(4-hydroxy-3-isopropylphenyl)propane through a carbonate linkage and is useful as a starting material for an optical disk.

Polycarbonate and optical disk therefrom

A plastic optical fiber comprising an aromatic polycarbonate copolymer having a photoelastic constant of 60 Brewsters (10.sup.-12 m.sup.2 /N) or less as a core component resin exhibits small birefringence.

Plastic optical fiber

An optical disk of the invention comprises a substrate of an aromatic polycarbonate obtained by polymerizing one or two monomers polymerized through carbonate linkages and a recording layer coated thereon, said recording layer being recordable and readable by a laser beam,

Optical disk of polycarbonate

An aromatic polycarbonate copolymer is useful for a substrate of an optical disk and is composed of 1 to 99 mole percent of the unit of 2,2-bis(4-hydroxy-3-tertiary-butyl-phenyl)propane, 99 to 1 mole percent of the unit of a comonomer selected from the group consisting of

Co-polycarbonate copolymer from 2,2-bis(4-hydroxy-3-tertiary butyl

A process for preparing polyamide elastomers is provided which process comprises reacting a polyamide-forming component having carboxyl groups at both ends thereof with polyoxyalkylene glycol(s) at least 10 wt. % of which comprises a polyoxy-2-methyl-1,3-propylenediol having a number-average molecular weight of about 400 to 10,000. The polyamide-forming component forms a polyamide block having a recurring unit of the formula: ##STR1## in which n represents a positive integer of 5 to 11, and/or ##STR2## in which l represents a positive integer of 6 to 20 and m represents a positive integer of 4 to 20. The obtained polyamide elastomers have excellent low-temperature properties and elastic recovery.

Polyamide elastomer from carboxy terminated polyamide and

A novel lactone-modified diol useful as a soft segment component which provides a thermoplastic elastomer showing excellent performances in elastic recovery and low-temperature properties is provided. This lactone-modified diol is represented by the general formula:

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Himeji, Japan

Kenichi Sasaki