Idemitsu Kosan Company, Limited

Hideyuki Miyamoto

Takaaki Hikosaka

Hironobu Morishita

Shuji Sakamoto

Tomohiro Nagao

Hiroichi Hokari

Chikayuki Chiba

Hitoshi Takemoto

A polycarbonate copolymer includes a repeating unit represented by a formula (1) below and a molar copolymer composition represented by Ar/(Ar+Ar) in a range of 25 mol % to 50 mol %. In the formula (1): Arand Arrepresent a divalent aromatic group; a chain end is terminated by a monovalent aromatic group or a monovalent fluorine-containing aliphatic group; and n represents an average repeating number of an Arblock and is a numeral of 1.0 to 3.0, provided that Arand Arare not the same.

Polycarbonate copolymer, coating liquid using same, and electrophotographic photosensitive body

A dihydric phenol compound represented by the following formula (2), a phosgene compound, and an aliphatic tertiary amine are mixed together using a hydrophobic organic solvent to produce bischloroformate that is represented by the following formula (1) and has an average number of repeating units (n) of 1.99 or less.  In the formulae (1) and (2), Ar is a divalent aromatic group.

Method for producing bischloroformate compound, polycarbonate oligomer having small number of monomers and solution containing bischloroformate compound

An electrophotographic photosensitive body having a photosensitive layer on a conductive base, in which at least the outermost layer thereof contains particles having a double structure composed of a core member and a shell member having a larger rubber hardness than the core member. The electrophotographic photosensitive body has excellent mechanical strength such as wear resistance, abrasion resistance, and scratch resistance as well as excellent electrophotographic characteristics such as cleaning properties over time.

Electrophotographic photosensitive body

A polyester polymer comprising repeating units (I), or repeating units (I) and (II), and having a reduced viscosity (.eta. sp/c) of 0.2 to 10.0 dl/g, measured at 20.degree. C. as a 0.5 g/dl solution dissolved in methylene chloride is prepared by allowing a dihydric phenol (III), or dihydric phenols (III) and (IV), to react with a carbonate precursor or a dibasic acid. An electrophotographic photoreceptor which comprises an electroconductive substrate and a photosensitive layer disposed on the electroconductive substrate and containing the polyester polymer as a charge transporting material or a binder resin. ##STR1## wherein, W is --O-- or single bond, X is a divalent group which is derived from a dihydric phenol containing a hydrazine structure, each of R.sup.25 and R.sup.26 is a halogen atom, an alkyl group, a cycloalkyl group or an aryl group, each of m and n is an integer of 0 to 4, Y is single bond, --O--, --S--, --SO--, --SO.sub.2 --, --CR.sup.27 R.sup.28 --, a 1,1-cycloalkylene group or an .alpha.,.omega.-alkylene group.

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Tokyo, Japan

Hideyuki Miyamoto