Toray Industries, Inc.

Sachio Inaba

Seiichiro Murase

Mitsuhito Suwa

Hiroji Shimizu

Shingo Hayashi

Yuji Iyama

Takuji Kobayashi

Ryoichi Hane

Kouichi Dan

Yoshihiro Ikegami

The present invention provides an electret fiber sheet having superior recovery of airflow volume by heat treatment and having high air permeability. The electret fiber sheet of the present invention is a nonwoven fabric formed from long fibers that are formed from a thermoplastic resin and have an average single fiber diameter of 0.1 to 8.0 &#x3bc;m, wherein a bulk density of the nonwoven fabric is 0.05 to 0.30 g/cmand the long fibers contain a crystal nucleating agent at 0.005 to 1.0% by mass.

Electret fiber sheet

An impurity-diffusing composition including (A) a polysiloxane represented by Formula (1) and (B) an impurity diffusion component.  In the formula, Rrepresents an aryl group having 6 to 15 carbon atoms, and a plurality of Rmay be the same or different. Rrepresents any of a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an acyl group having 2 to 6 carbon atoms, and an aryl group having 6 to 15 carbon atoms, and a plurality of Rmay be the same or different. Rand Reach represent any of a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an acyl group having 2 to 6 carbon atoms, and a plurality of Rand a plurality of Reach may be the same or different. The ratio of n:m is 95:5 to 25:75.

Impurity-diffusing composition and method for producing semiconductor element

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Otsu, Japan

Sachio Inaba