An optical fiber comprises a glass fiber comprising a core and a cladding, and a coating resin layer covering the outer periphery of the glass fiber, wherein the average linear expansion coefficient of the coating resin layer at −50° C. or more and 0° C. or less is 3.3×10.sup.−5/° C. or more and less than 9.0×10.sup.−5/° C.

An optical fiber comprises a glass fiber comprising a core and a cladding, and a coating resin layer covering the outer periphery of the glass fiber, wherein the average linear expansion coefficient of the coating resin layer at −50° C. or more and 0° C. or less is 3.3×10.sup.−5/° C. or more and less than 9.0×10.sup.−5/° C.

An optical fiber ribbon is intermittently connected in a length direction by an intermittent connection which includes a polyol having a weight-average molecular weight of 3000 to 4000 in a specific amount relative to the entire intermittent connection and which has Young's modulus at 23 C. within a specific range. When collectively unitizing optical fiber ribbons to form an optical fiber cable, an optical fiber ribbon is formed which maintains advantages of the optical fiber ribbon and which prevents cracks of the intermittent connection and detachment of the intermittent connection from a colored optical fiber core when the cable is subjected to repetitive ironing.

An optical fiber ribbon is intermittently connected in a length direction by an intermittent connection which includes a polyol having a weight-average molecular weight of 3000 to 4000 in a specific amount relative to the entire intermittent connection and which has Young's modulus at 23 C. within a specific range. When collectively unitizing optical fiber ribbons to form an optical fiber cable, an optical fiber ribbon is formed which maintains advantages of the optical fiber ribbon and which prevents cracks of the intermittent connection and detachment of the intermittent connection from a colored optical fiber core when the cable is subjected to repetitive ironing.

A curable formaldehyde-free binding composition for use with fiberglass is provided. Such curable composition comprises an aldehyde or ketone and an amine salt of an inorganic acid. The composition when applied to fiberglass is cured to form a water-insoluble binder which exhibits good adhesion to glass. In a preferred embodiment the composition when applied to fiberglass provides a sufficient blackness required in facer products.

A curable formaldehyde-free binding composition for use with fiberglass is provided. Such curable composition comprises an aldehyde or ketone and an amine salt of an inorganic acid. The composition when applied to fiberglass is cured to form a water-insoluble binder which exhibits good adhesion to glass. In a preferred embodiment the composition when applied to fiberglass provides a sufficient blackness required in facer products.

The present invention is directed to a solid state binder composition for binding mineral fibers comprising a component (i) in form of one or more carbohydrates; a component (ii) in form of one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof.

The present invention is directed to a solid state binder composition for binding mineral fibers comprising a component (i) in form of one or more carbohydrates; a component (ii) in form of one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof.

A light irradiation device includes a light source having a plurality of solid-state elements disposed on a substrate to be defined by a first direction and a second direction in a plurality of rows and irradiate the irradiation target with light from a third direction, an optical element refracting light from the solid-state elements, emitting the light and narrowing a spread angle of light to be emitted from the solid-state elements relative to the third direction, a first reflection portion having at least two first reflection surfaces on a downstream side in the third direction of the irradiation target and reflecting a part of light incident on the first reflection surface to the irradiation target, and a second reflection portion having a pair of second reflection surfaces disposed between the optical element and the first reflection portion and guiding light from the optical element to the first reflection surface.

A light irradiation device includes a light source having a plurality of solid-state elements disposed on a substrate to be defined by a first direction and a second direction in a plurality of rows and irradiate the irradiation target with light from a third direction, an optical element refracting light from the solid-state elements, emitting the light and narrowing a spread angle of light to be emitted from the solid-state elements relative to the third direction, a first reflection portion having at least two first reflection surfaces on a downstream side in the third direction of the irradiation target and reflecting a part of light incident on the first reflection surface to the irradiation target, and a second reflection portion having a pair of second reflection surfaces disposed between the optical element and the first reflection portion and guiding light from the optical element to the first reflection surface.