Nippon Telegraph and Telephone Public Corporation

Nippon Telegraph and Telephone Corporation

Japan Synthetic Rubber Co., Ltd.

Shinzo Yamakawa

Takao Kimura

Fumio Yamamoto

Mitsutoshi Hoshino

Makoto Wagatsuma

Osamu Maeda

Yoshito Shuto

Norio Murata

Koichi Nakagawa

Ryotaro Ohono

A coated optical fiber comprising an optical fiber; a first layer of a thermoplastic rubber composition which is disposed around the circumference of the optical fiber, has a Young's modulus of 0.1 GPa or less, and is capable of extrusion coating; and a second layer of a thermoplastic resin composition which is disposed around the circumference of the first layer, has a linear expansion coefficient of 1.times.10.sup.-5.degree. C..sup.-1 or less and a Young's modulus of 5 GPa or more, and is capable of extrusion coating. The coated optical fiber has excellent transmission characteristics at low and high temperatures and is inexpensive.

Coated optical fiber, fabrication process thereof and fabrication

A UV-ray curable resin composition comprising a polyurethane derived from a polyether polyol and a diene polymer having hydroxyl group, said polyurethane having polymerizable double bond different from the carbon-carbon double bonds contained in said diene polymer having hydroxyl group, and a coated optical fiber having a coated layer comprising the cured product of said resin composition. This composition has good coating characteristics, and the cured product thereof has small modulus over a wide temperature range and good hydrolysis resistance, and water absorption resistance. The coated optical fiber has small transmission loss over a wide temperature range and has high strength even in water.

UV-ray curable polyurethane composition and coated optical fiber

A protective packaging method of protecting the spliced portion of optical fibers, comprising the steps of providing a protective packaging assembly having a heat-shrinkable tube capable of shrinking in the radial direction thereof, an extended form of hot-melt adhesive disposed on the inner side of the heat-shrinkable tube, and an electrical resistance heating element so disposed on the inner side of the heat-shrinkable tube and extendedly in the axial direction of the heat-shrinkable tube as to be capable of heating both the heat-shrinkable tube and the extended form of hot-melt adhesive, and a space provided in the heat-shrinkable tube for allowing the passage of the optical fiber; placing the protective packaging assembly around the splice portion of the optical fiber which has been passed through the space; and supplying electric current through the electrical resistance heating element to heat-melt the hot-melt adhesive and to heat-shrink the heat-shrinkable tube for forming a reinforced unit including the spliced portion of the optical fiber and the electrical resistance heating element with the hot-melt adhesive acting as a sealant inside the heat-shrunk tube. A highly reliable reinforced portion is easily and rapidly formed which does not contain residual bubbles. The reinforced fiber is hardly broken and has little increase of transmission loss.

Protective packaging assembly and method

This invention discloses a continuous process for the production of polymer-polyoxymethylene (POM) having small linear expansion coefficients and high tensile modulus, the process for producing an ultrahigh modulus POM comprising the step of drawing a crystalline polymer continuously under dielectric heating while maintaining the ambient temperature at an elevated temperature by external heating, said ambient temperature being controlled to change from a lower temperature to a higher temperature along the drawing direction of said crystalline polymer with a pre-set temperature gradient.

Drawing of polyoxymethylene using dielectric heating

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Katsuta, Japan

Shinzo Yamakawa