Ube Industries, Inc.

Yoshiyuki Watanabe

Yukinori Kohama

Takuya Oka

Nobuharu Hisano

Kenji Hirotsu

Takashi Doi

Satoru Fujitsu

Yoshihiro Yoshida

Ryoichi Takasawa

Keiji Iwamoto

Daisuke Douyama

Shinji Yasuda

Miharu Nakagawa

A polyimide precursor including at least one repeating unit represented by the following chemical formula (1): 

Polyimide precursor and polyimide

A polyimide precursor comprising a repeating unit represented by the following chemical formula (1):   

Polyimide precursor, polyimide, varnish, polyimide film, and substrate

A polyimide precursor comprising at least one repeating unit represented by the following chemical formula (5): in which Ais a divalent group of an aromatic diamine or an aliphatic diamine, from which amino groups have been removed; and Xand Yare each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms, and/or at least one repeating unit represented by the following chemical formula (6): in which Ais a divalent group of an aromatic diamine or an aliphatic diamine, from which amino groups have been removed; and Xand Yare each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms.

Polyimide precursor, polyimide, polyimide film, varnish, and substrate

The present invention relates to a polyimide precursor comprising a repeating unit represented by the following chemical formula (1): wherein A is a tetravalent group having at least one aliphatic six membered ring and no aromatic ring in the chemical structure, and B is a divalent group having at least one amide bond and an aromatic ring in the chemical structure; or A is an aliphatic tetravalent group and B is a divalent group having at least one chemical structure represented by the following chemical formula (2) in the chemical structure: and Xand Xare each independently hydrogen, a Calkyl group or a Calkylsilyl group.

An object of the present invention is to provide an industrially advantageous process for preparing a benzaldehyde compound from a benzyl alcohol compound with high yield. The present invention relates to a process for preparing an aromatic aldehyde compound represented by the formula (2); which comprises reacting an aromatic methyl alcohol compound represented by the formula (1); and a peroxide under a pH value of a reaction solution being pH 0.01 or higher and less than 10 in the presence of at least one metallic compound selected from a molybdenum compound and a tungsten compound, a quaternary ammonium salt and an organic phosphonium salt.

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Ube, Japan

Yoshiyuki Watanabe