Toray Industries, Inc.

Takeshi Sugimoto

Yuhei Maeda

Koji Sugano

Tomoko Takano

Reo Mitsunaga

Tatsuya Mori

Keiji Kaiho

Koichiro Maeda

A laminated polyarylene sulfide heat-resistant filter has a plurality of layers, at least including a first web layer that is a filtering surface, and a second web layer that is a non-filtering surface, the laminated polyarylene sulfide heat-resistant filter being characterized in that the first web layer contains 30 to 70 wt % of polyarylene sulfide fibers having a fineness of 0.5 to 1.2 dtex, and 30 to 70 wt % of polyarylene sulfide fibers having a fineness of 1.3 to 3.0 dtex taking a total of a weight percentages of the first web layer as 100 wt %, wherein the second web layer contains polyarylene sulfide fibers having a fineness of 1.0 to 4.0 dtex.

Laminated polyarylene sulfide heat-resistant filter

The present invention provides: a polyphenylene sulfide fiber that has excellent tensile strength; and a polyphenylene sulfide fiber that decreases in toughness to a small extent even when subjected to a long-term heat treatment and has excellent tensile strength. The polyphenylene sulfide fiber according to the present invention is characterized by comprising a polyphenylene sulfide resin having a weight average molecular weight of 50000 to 80000 inclusive, having a rigid amorphous content of 50% or more, and having a crystal size of 5 nm or more in the direction of a (111) crystal plane.

Polyphenylene sulfide fiber, filter cloth comprising polyphenylene sulfide fiber, and method for producing polyphenylene sulfide fiber

A polyphenylene sulfide fiber has an amount of heat of crystallization measured by DSC is 10 J/g or more and the degree of shrinkage on dry heating of 150&#xb0; C.&#xd7;30 minutes is 20% or less. A method produces a densified wet-laid nonwoven fabric by subjecting paper produced in a papermaking process and containing 60 to 100% by mass of a polyphenylene sulfide fiber having an amount of heat of crystallization of 10 J/g or more and an amount of heat of crystallization of the wet-laid nonwoven fabric before heating-pressurizing treatments is 5 J/g or more to heating-pressurizing treatment at a temperature that is not lower than the glass transition temperature and not higher than the melting point of the polyphenylene sulfide fiber.

Polyphenylene sulfide fiber, method for producing the same, wet-laid nonwoven fabric, and method for producing wet-laid nonwoven fabric

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Iyo-gun, Japan

Takeshi Sugimoto