Provided is a reinforcing fiber mat including a reinforcing fiber mat constituted by reinforcing fibers having an average fiber length of 3 to 100 mm. The reinforcing fibers satisfy the following i) to iv): i) a weight-average fiber width (Ww) of the reinforcing fibers satisfies the following Equation (1):
0.03 mm<Ww<5.0 mm   (1);
ii) an average fiber width dispersion ratio (Ww/Wn) defined as a ratio of the weight-average fiber width (Ww) to a number-average fiber width (Wn) of the reinforcing fibers is 1.8 or more and 20.0 or less; iii) a weight-average fiber thickness of the reinforcing fibers is smaller than the weight-average fiber width (Ww); and iv) a fiber width distribution of the reinforcing fibers included in the reinforcing fiber mat has at least two peaks.

Provided is a reinforcing fiber mat including a reinforcing fiber mat constituted by reinforcing fibers having an average fiber length of 3 to 100 mm. The reinforcing fibers satisfy the following i) to iv): i) a weight-average fiber width (Ww) of the reinforcing fibers satisfies the following Equation (1):
0.03 mm<Ww<5.0 mm   (1);
ii) an average fiber width dispersion ratio (Ww/Wn) defined as a ratio of the weight-average fiber width (Ww) to a number-average fiber width (Wn) of the reinforcing fibers is 1.8 or more and 20.0 or less; iii) a weight-average fiber thickness of the reinforcing fibers is smaller than the weight-average fiber width (Ww); and iv) a fiber width distribution of the reinforcing fibers included in the reinforcing fiber mat has at least two peaks.

A synthetic leather has excellent flame retardance and an article covered with the synthetic. The synthetic leather includes a fiber base material layer formed of a non-woven fabric sheet, wherein the non-woven fabric sheet includes at least one flameproof layer formed of a web including a non-melting fiber A having a high-temperature shrinkage rate of 3% or less and a thermal conductivity, conforming to ISO22007-3 (2008), of 0.060 W/m.Math.K or less and is formed by bonding the flameproof layer to a scrim layer including a carbonized heat-resistant fiber B having an LOI value, conforming to JIS K 7201-2 (2007), of 25 or more, and a resin layer is laminated on a surface of the scrim layer, and a covered article covered with the synthetic leather.

An aramid paper suitable for use in electronic applications which has a density of 0.20-0.65 g/cm3 and a grammage of 30-280 g/m2, which paper comprises 10-40 wt. % of aramid shortcut with a linear density of 2.6 dtex or lower and a length of 0.5-25 mm and 10-90 wt. % of aramid fibrid, wherein the aramid shortcut comprises at least 70 wt. % para-aramid shortcut and the aramid fibrid including at least 70 wt. % para-aramid fibrid. It has been found that the use of a paper with the above properties in electronic applications ensures a low CTE in combination with good homogeneity and a good dimensional stability resulting from good resin adhesion and penetration. Use of the aramid paper in a composite sheet including at least one layer of aramid paper and a resin, or in a substrate board for electronic applications.

A hot press cushioning material includes: a first nonwoven fabric forming an inner layer; and second nonwoven fabrics placed on both surfaces of the first nonwoven fabric and forming outer layers. Copolymerized para-aramid fibers having a basis weight of 80 to 400 g/m.sup.2 are used as a material of the second nonwoven fabrics. Fibers that are more rigid than the copolymerized para-aramid fibers are used as a material of the first nonwoven fabric. Each of the first nonwoven fabric and the second nonwoven fabrics has a heat resistant temperature of 270° C. or more.

A hot press cushioning material includes: a first nonwoven fabric forming an inner layer; and second nonwoven fabrics placed on both surfaces of the first nonwoven fabric and forming outer layers. Copolymerized para-aramid fibers having a basis weight of 80 to 400 g/m.sup.2 are used as a material of the second nonwoven fabrics. Fibers that are more rigid than the copolymerized para-aramid fibers are used as a material of the first nonwoven fabric. Each of the first nonwoven fabric and the second nonwoven fabrics has a heat resistant temperature of 270° C. or more.

An alumina-silica hydrate fiber for thermal protection in the most hazardous environments experienced by firefighters. The fiber has a combination of heat resistance at temperatures above 1,000° C. and an endothermic behavior when heated. Its endothermic condensation reaction releases up to 12% water upon heating, thereby contributing to the thermal insulating properties. The fibers are extremely soft to the touch and do not irritate the skin. They are also non-respirable in the deep lung, so they can be used safely without risk of inhalation. The fabric is sufficiently lightweight and flexible as well, allowing firefighters to move easily. These properties of alumina-silica hydrate fibers enable their use for apparel.

A safety garment material is designed to be used in high temperature environments where aluminized personal protection equipment is required gear to protect workers from high radiant heat as well as accidental molten metal splashing or spills. The material includes a plurality of layers of nonwoven fire-resistant oxidized polyacrylonitrile (OPAN) arranged in a wicking configuration to wick moisture away from the wearer's body and layer of perforated aluminized film to allow escape of moisture from the wearer's body.

Provided is a polymer nanofiber sheet having high delamination resistance, a high mechanical strength, and a high specific surface area. Specifically, provided is a polymer nanofiber sheet, including polymer nanofibers, the polymer nanofibers being laminated and three-dimensionally entangled with each other, in which: at least part of the polymer nanofibers are crosslinked at a crosslinked part having crosslinking portions and a non-crosslinking portion; and the crosslinked part contains a low-molecular weight epoxy compound having a molecular weight of from 100 to 3,000.

Provided is a polymer nanofiber sheet having high delamination resistance, a high mechanical strength, and a high specific surface area. Specifically, provided is a polymer nanofiber sheet, including polymer nanofibers, the polymer nanofibers being laminated and three-dimensionally entangled with each other, in which: at least part of the polymer nanofibers are crosslinked at a crosslinked part having crosslinking portions and a non-crosslinking portion; and the crosslinked part contains a low-molecular weight epoxy compound having a molecular weight of from 100 to 3,000.