Shin-Etsu Chemical Co., Ltd.

Shin-Etsu Chem Co., Ltd.

Tomohisa Suzuki

Tadashi Amano

Shoji Ichinohe

Toshio Shinohara

Masanao Kamei

Kenichi Isobe

Hideshi Kurihara

Mitsuo Asai

Takashi Kobayashi

Akira Yamamoto

Tohru Nishikawa

Silicon-containing peroxyester compounds, for example, represented by the following formula: ##STR1## useful as a polymerization initiator, which compounds can produce vinyl chloride polymers having a high quality in a high yield and in a short reaction time.

Silicon-containing peroxyesters

A water soluble water absorption preventing agent mainly comprising an organic silicon compound and/or its partial hydrolytic condensate, represented by the following general formula: ##STR1## wherein R.sup.1 denotes an alkyl group with 1-20 carbon atoms and with a linear chain or branched chain for which a halogen can substitute for part or all of the hydrogen atoms, R.sup.2 denotes a hydrogen atom or an alkyl group with 1-10 carbon atoms and with a linear chain or branched chain, R.sup.3 denotes a hydrogen atom or an alkyl group with 1-8 carbon atoms and with a linear chain or branched chain, m denotes an integer 1-2 and n denotes an integer 1-3 where m+n=3 or 4, p denotes an integer 1-50, and q denotes an integer 0-25.

Water absorption preventing agent having water solubility and a method

A diorganopolysiloxane terminated only at one of the molecular chain ends with a (meth)acryloxyalkyl group bonded to the terminal silicon atom is prepared, instead of the prior art method in which a diorganopolysiloxane obtained by the anionic ring-opening living polymerization reaction of, for example, hexamethyl cyclotrisiloxane by using a lithium catalyst is subjected to a desalinating condensation reaction with a (meth)acryloxyalkyl dimethyl chlorosilane, by a novel method in which the diorganopolysiloxane obtained by the anionic ring-opening living polymerization reaction of, for example, hexamethyl cyclotrisiloxane is hydrolyzed and the thus obtained monofunctionally silanol-terminated diorganopolysiloxane is reacted with a (meth)acryloxyalkyl dimethyl dialkylamino silane to effect a deamination reaction. This method is advantageous in that the relatively narrow molecular weight distribution of the diorganopolysiloxane obtained by the anionic living polymerization is not affected and retained as such in the deamination reaction while not in the prior art method.

Method for the preparation of an organopolysiloxane polymerizable at a

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Gunma, Japan

Tomohisa Suzuki