Abstract: This invention provides an illuminating device characterized in that the device comprises a light-transmitting rod for transmitting the light incident on one end thereof toward the otehr end, a diffusion pattern formed on the outer peripheral surface of the rod by adhering a fine powder of high refractive index in the shape of a line extending continuously or discretely axially of the rod, and a transparent protective tube covering the peripheral surface of the rod with a circumferential clearance formed between the rod and the tube, the clearance between the rod and the protective tube being sealed off at opposite ends thereof.

Abstract: A process for preparing polytetrafluoroethylene fine powder by polymerization of tetrafluoroethylene in an aqueous medium comprising a water-soluble polymerization initiator and a non-telogenic surfactant capable of keeping colloidal polytetrafluoroethylene particles at a sufficiently stable state, characterized in that the polymerization is carried out at a temperature of 55.degree. to 120.degree. C., and a polymerization retarder chosen from aromatic hydroxy compounds, aromatic amino compounds and quinone compounds which has a water-solubility of not less than 2.5.times.10.sup.-6 mol/liter at 25.degree. C. and does not have any reinitiation ability after its addition or chain transfer to a free radical in the polymerization system is incorporated in the aqueous medium in an amount of 0.

Abstract: Polytetrafluoroethylene fine powders which have an average molecular weight of not less than 5,000,000, preferably not less than 5,500,000, an amorphous index of not more than 0.1, preferably not more than 0.09, a number average primary particle size of 0.1 to 0.4 micron, preferably 0.15 to 0.38 micron, and a sharp endothermic peak at a temperature between 343.degree. C. and 350.degree. C. on the melting diagram by a differential scanning calorimeter, said sharp peak having an endothermic ratio of not more than 0.3, preferably not more than 0.27, and a half value width of the endothermic peak of not more than 8 degrees, preferably not more than 6 degrees, and a process for producing the polytetrafluoroethylene fine powders. The polytetrafluoroethylene fine powders have an excellent stretchability and are useful for electric wire coating, small diameter tubes, large diameter tubes, sealing tapes and the like.

Abstract: A process for preparing a polytetrafluoroethylene fine powder by polymerizing tetrafluoroethylene in an aqueous medium containing a polymerization initiator and a dispersant, coagulating the resulting polymer, washing the coagulated polymer when desired, and drying the polymer, characterized in that after at least 30 wt. % of the whole amount of the tetrafluoroethylene to be polymerized has been polymerized at a constant temperature, the polymerization is conducted at an altered temperature at which the same whole amount, when polymerized, gives a polymer having an amorphous index at least 0.01 higher than when the whole amount is polymerized at the first-mentioned temperature.

Abstract: An air-pervious sheet predominantly of polytetrafluoroethylene, the sheet being reinforced by being fused to a liquid-pervious reinforcing material layer which is capable of retaining its original form even when heated to a temperature of 270.degree. to 280.degree. C. The sheet preferably consists of a polytetrafluoroethylene fibrous powder having an average fiber length of 100 to 5,000 microns, an average shape factor of not less than 10, and an anisotropic expansion factor of 1.30 to 7.00 adhered by means of molten polytetrafluoroethylene having an average particle diameter of 0.05 to 0.5 microns to a liquid-pervious reinforcing material layer which is capable of retaining its original form even when heated to a temperature of 270.degree. C. to 380.degree. C.

Abstract: A fluoroelastomer composition which contains (a) a fluoroelastomer, (b) at least one metal compound selected from the group consisting of bivalent metal oxide, bivalent metal hydroxide and mixture of bivalent metal oxide or metal hydroxide with metal salt of weak acid, (c) an aromatic polyhydroxy compound, (d) a quaternary ammonium compound of 8-alkyl- or 8-aralkyl-1,8-diaza-bicyclo[5.4.0]-7-undecenium, and (e) 1,8-diaza-bicyclo[5.4.0]-7-undecene in an amount of not more than 0.07 part by weight per 100 parts by weight of fluoroelaster, provides a fluoro-rubber having a low compression set and an excellent elastic property. The fluoroelastomer composition can be handled and processed with safety, and yet can be cured with an appropriate induction time and a good cure rate, and has excellent storage properties.

Abstract: A fluoroelastomer composition which contains (a) a fluoroelastomer, (b) at least one member selected from the group consisting of bivalent metal oxide, bivalent metal hydroxide and mixture of bivalent metal oxide or metal hydroxide with metal salt of weak acid, (c) an aromatic polyhydroxy compound, and (d) a quaternary ammonium compound of imidazole or imidazoline, provides a fluoro-rubber having a low compression set and an excellent elastic property. The fluoroelastomer composition can be handled and processed with safety, and yet can be cured at a good cure rate, and has excellent storage properties. The cure rate of the composition is more accelerated by further addition of (e) water or a metal compound which produces water by reacting it with hydrogen fluoride.

Abstract: A fluoroelastomer composition which contains (a) a fluoroelastomer, (b) at least one member selected from the group consisting of bivalent metal oxide, bivalent metal hydroxide and mixture of bivalent metal oxide or metal hydroxide with metal salt of weak acid, (c) an aromatic polyhydroxy compound, and (d) a quaternary ammonium compound of 8-alkyl- or 8-aralkyl-1,8-diaza-bicyclo[5.4.0]-7-undecenium, provides a fluoro-rubber having a low compression set and an excellent elastic property. The fluoroelastomer composition can be handled and processed with safety, and yet can be cured with a good cure rate, and has excellent storage properties. The cure rate of the composition is further accelerated by addition of (e) water or a metal compound which produces water by reacting it with hydrogen fluoride.

Abstract: Polytetrafluoroethylene fine powders which have an average molecular weight of not less than 5,000,000, preferably not less than 5,500,000, an amorphous index of not more than 0.1, preferably not more than 0.09, a number average primary particle size of 0.1 to 0.4 micron, preferably 0.15 to 0.38 micron, and a sharp endothermic peak at a temperature between 343.degree. C. and 350.degree. C. on the melting diagram by a differential scanning calorimeter, said sharp peak having an endothermic ratio of not more than 0.3, preferably not more than 0.27, and a half value width of the endothermic peak of not more than 8 degrees, preferably not more than 6 degrees, and a process for producing the polytetrafluoroethylene fine powders. The polytetrafluoroethylene fine powders have an excellent stretchability and are useful for electric wire coating, small diameter tubes, large diameter tubes, sealing tapes and the like.