Abstract: Disclosed is an electromagnetic casting method of polycrystalline silicon which is characterized in that polycrystalline silicon is continuously cast by charging silicon raw materials into a bottomless cold mold, melting the silicon raw materials using electromagnetic induction heating, and pulling down the molten silicon to solidify it, wherein the depth of solid-liquid interface before the start of the final solidification process is decreased by reducing a pull down rate of ingot in a final phase of steady-state casting. By adopting the method, the region of precipitation of foreign substances in the finally solidified portion of ingot can be reduced and cracking generation can be prevented upon production of a polycrystalline silicon as a substrate material for a solar cell.

Abstract: Provided is a continuous casting method of a silicon ingot for continuously casting the silicon ingot by arranging, inside an induction coil, a bottomless cold crucible having a part along an axial direction that is circumferentially divided into a plurality of strip elements, forming molten silicon inside the cold crucible through electromagnetic induction heating by the induction coil, and solidifying the molten silicon while pulling it down from the cold crucible, wherein as the cold crucible, used is a cold crucible with Ni—B alloy plating on a portion in the inner surface thereof that faces the outer side surface of the molten silicon and the outer surface of the silicon ingot. The method can reduce the damage to the inner surface of the cold crucible, in addition to the contamination of cast ingots with impurities.

Abstract: Provided is a silicon electromagnetic casting apparatus that is capable of stably producing polycrystalline silicon used as a solar cell substrate material, having a bottomless cold mold and an induction heating coil, the apparatus for pulling down the silicon melted through electromagnetic induction heating by means of the induction coil and solidifying the silicon melt; further including a plasma torch for generating a transferable plasma arc and a top heater configured so as to face a top surface of the molten silicon, the top heater for generating heat through electromagnetic induction by means of the induction coil. The apparatus enables, upon production of a high quality polycrystalline silicon ingot as a solar cell substrate material along with plasma heating, stable production thereof without cracking in a final solidification portion.

Abstract: Disclosed is an electromagnetic casting method of polycrystalline silicon which is characterized in that polycrystalline silicon is continuously cast by charging silicon raw materials into a bottomless cold mold, melting the silicon raw materials using electromagnetic induction heating, and pulling down the molten silicon to solidify it, wherein the depth of solid-liquid interface before the start of the final solidification process is decreased by reducing a pull down rate of ingot in a final phase of steady-state casting. By adopting the method, the region of precipitation of foreign substances in the finally solidified portion of ingot can be reduced and cracking generation can be prevented upon production of a polycrystalline silicon as a substrate material for a solar cell.

Abstract: Provided is a continuous casting method of a silicon ingot for continuously casting the silicon ingot by arranging, inside an induction coil, a bottomless cold crucible having a part along an axial direction that is circumferentially divided into a plurality of strip elements, forming molten silicon inside the cold crucible through electromagnetic induction heating by the induction coil, and solidifying the molten silicon while pulling it down from the cold crucible, wherein as the cold crucible, used is a cold crucible with Ni—B alloy plating on a portion in the inner surface thereof that faces the outer side surface of the molten silicon and the outer surface of the silicon ingot. The method can reduce the damage to the inner surface of the cold crucible, in addition to the contamination of cast ingots with impurities.

Abstract: Disclosed is an electromagnetic casting method of a silicon ingot in which a polycrystalline silicon ingot is continuously cast by charging silicon raw materials into a bottomless cold copper mold, melting the charged silicon raw materials through electromagnetic induction, pulling down to solidify the molten silicon, in which the length of a part of copper mold positioned below a lower end of an induction coil surrounding the copper mold is set to more than 40 mm and 180 mm or less. According to this method, a copper contamination of a silicon ingot incurred by a copper cold mold can be suppressed to produce a silicon ingot which is suitable as a starting material of the substrate of a solar cell.

Abstract: Provided is a silicon electromagnetic casting apparatus that is capable of stably producing polycrystalline silicon used as a solar cell substrate material, having a bottomless cold mold and an induction heating coil, the apparatus for pulling down the silicon melted through electromagnetic induction heating by means of the induction coil and solidifying the silicon melt; further including a plasma torch for generating a transferable plasma arc and a top heater configured so as to face a top surface of the molten silicon, the top heater for generating heat through electromagnetic induction by means of the induction coil. The apparatus enables, upon production of a high quality polycrystalline silicon ingot as a solar cell substrate material along with plasma heating, stable production thereof without cracking in a final solidification portion.

Abstract: The present invention includes a method for casting a silicon ingot by using a continuous casting method by means of an electromagnetic induction, and a method for cutting the silicon ingot as a starting material into plural silicon blocks. When the silicon blocks with a square section are cut out, the sectional shape of the silicon ingot is set to be rectangular. Not less than 6 pieces of equal-sized silicon blocks are cut out from the silicon ingot, thereby enabling to enhance the manufacturing efficiency to a great extent. And since the amount of excision of the edge per silicon block is reduced, the production yield can be enhanced. Further, since the proportion of columnar crystals with large grain size inside the ingot can be increased, it becomes possible to enhance the conversion efficiency of a solar battery using the silicon block as a substrate material.

Abstract: In a silicon casting apparatus according to the present invention, silicon melted by electromagnetic induction heating is continuously solidified using an electrically-conductive bottomless cold crucible and an induction coil surrounding the cold crucible. The cold crucible is made of copper alloy containing beryllium (desirably containing beryllium of 0.1 to 5 mass %), whereby the generation of electric-discharge flaw can be effectively prevented in performing electromagnetic casting. The use of the silicon casting apparatus according to the present invention can greatly extend a crucible life to reduce facility costs. Additionally, a solar-cell silicon ingot can be produced with high quality.

Abstract: The present invention includes a method for casting a silicon ingot by using a continuous casting method by means of an electromagnetic induction, and a method for cutting the silicon ingot as a starting material into plural silicon blocks. When the silicon blocks with a square section are cut out, the sectional shape of the silicon ingot is set to be rectangular. Not less than 6 pieces of equal-sized silicon blocks are cut out from the silicon ingot, thereby enabling to enhance the manufacturing efficiency to a great extent. And since the amount of excision of the edge per silicon block is reduced, the production yield can be enhanced. Further, since the proportion of columnar crystals with large grain size inside the ingot can be increased, it becomes possible to enhance the conversion efficiency of a solar battery using the silicon block as a substrate material.

Abstract: An optical fiber coated with a reinforcing material having an excellent heat resistance and a process for producing the same are disclosed. The reinforcing material comprises continuous filaments having impregnated therein a curable composition comprising(a) tri(meth)acrylate of trishydroxylalkyl isocyanurate,(b) a modified phenol novolak-based resin having (meth)acryloyl groups in the molecule, and(c) a polymerization initiator.

Abstract: A coating material for optical glass fibers is disclosed. The material is comprised of 1,4-polybutadienes having functional groups or modified polybutadienes derived from the 1,4-polybutadienes having introduced therein polymerizable double bonds different from the double bonds present in the 1,4-polybutadienes.

Abstract: A reinforced plastic molding having excellent heat resistance, toughness and adhesion property to a fibrous substrate is disclosed, comprising a fibrous substrate having impregnated and cured therein a curable composition comprising tri(meth)acrylate of trishydroxyalkyl isocyanurate, a modified phenol novolak-based epoxy resin and a polymerization initiator.

Abstract: Coated optical glass fibers are described, wherein the coating composition comprises an unsaturated polyester containing at least one of (1) polyethylene glycol or polypropylene glycol having an average molecular weight of from 200 to 1,000 as a glycol component, (2) a long chain saturated aliphatic dibasic acid containing 12 or more carbon atoms as saturated polybasic acid component, and an acrylate or methacrylate, and (3) a long chain saturated aliphatic dibasic acid containing 6 or more carbon atoms as a saturated polybasic acid component and a long chain aliphatic dihydric alcohol containing 4 or more carbon atoms as a glycol component; and an acrylate or methacrylate.

Abstract: A water-solubilized resin composition for forming a thermally stable polyimide polymer prepared by mixing(I) a nitrogenous base salt of a polyimide precursor containing an amino group at both terminals of the molecule and having a residual acid value ratio of about 50 to about 5% obtained by reacting 1,2,3,4-butanetetracarboxylic acid and a molar excess of a diamine in water, or in a water-soluble solvent or in the presence of both a water-soluble solvent and water with(II) a nitrogenous base salt of a 3,3',4,4'-benzophenonetetracarboxylic acid diester whose ester linkage is positioned at either one of the adjoining two carboxyl groups in the same benzene nucleus thereof.