Abstract: The present invention relates to a method for producing a prepreg which contains reinforcing fibers and a matrix resin composition with the weight per square meter of the reinforcing fibers being 250-2,000 g/m2. The production method comprises the following steps (1)-(3): (1) a matrix resin composition blending step for obtaining a matrix resin composition by mixing an epoxy resin, a radically polymerizable unsaturated compound, an epoxy resin curing agent and a polymerization initiator that generates radicals, in said step the content of the radically polymerizable unsaturated compound relative to 100% by mass of the total of the epoxy resin and the radically polymerizable unsaturated compound being 10-25% by mass; (2) a matrix resin composition impregnating step; and (3) a surface viscosity increasing step.

Abstract: Disclosed is a production system (1) for a carbon fiber thread (Z) by continuously subjecting a carbon fiber thread precursor (X) having a jointed portion (a) connecting respective ends of two carbon fiber thread precursors (X) to heat treatment, which contains an oxidization oven (10) for subjecting the carbon fiber thread precursor (X) to an oxidization treatment, a carbonization furnace (12) for subjecting a thus obtained oxidized fiber thread to a carbonization treatment, a winder (18) for winding the carbon fiber thread (Z) around a winding bobbin, a detection means (24) for detecting the jointed portion (a), a positional information-acquisition means (26) for acquiring positional information of the jointed portion (a), a control means (28) for controlling the winder (18) in such a way that a carbon fiber thread including the jointed portion (a) and a carbon fiber thread not including the jointed portion (a) are separately wound up around different winding bobbins based on the positional information.

Abstract: According to the present invention, a porous electrode substrate with greater sheet strength, lower production cost, and excellent gas permeability and conductivity as well as its manufacturing method are provided. Also provided are a precursor sheet for forming such a substrate, and a membrane electrode assembly and a polymer electrolyte fuel cell containing such a substrate. The method for manufacturing such a porous electrode substrate includes the following steps [1]˜[3]: [1] a step for manufacturing a sheet material in which short carbon fibers (A) are dispersed; [2] a step for manufacturing a precursor sheet by adding a water-soluble phenolic resin and/or water-dispersible phenolic resin to the sheet material; and [3] a step for carbonizing the precursor sheet at a temperature of 1000° C. or higher.

Abstract: Disclosed is a production system (1) for a carbon fiber thread (Z) by continuously subjecting a carbon fiber thread precursor (X) having a jointed portion (a) connecting respective ends of two carbon fiber thread precursors (X) to heat treatment, which contains an oxidization oven (10) for subjecting the carbon fiber thread precursor (X) to an oxidization treatment, a carbonization furnace (12) for subjecting a thus obtained oxidized fiber thread to a carbonization treatment, a winder (18) for winding the carbon fiber thread (Z) around a winding bobbin, a detection means (24) for detecting the jointed portion (a), a positional information-acquisition means (26) for acquiring positional information of the jointed portion (a), a control means (28) for controlling the winder (18) in such a way that a carbon fiber thread including the jointed portion (a) and a carbon fiber thread not including the jointed portion (a) are separately wound up around different winding bobbins based on the positional information.

Abstract: The present invention relates to a carbon fiber nonwoven band-shaped article obtained by cutting a needle-punch nonwoven fabric of carbon fiber, wherein the carbon fiber is primarily oriented in a direction substantially perpendicular to a cut face of the band-shaped article. The band-shaped article can be manufactured by needle-punching a laminate web in which staples of fire-resistant fibers are oriented in substantially one direction, carbonizing an obtained nonwoven fabric by sintering and then cutting a carbonized nonwoven fabric in a direction substantially perpendicular to the direction of an orientation of the staples.