Abstract: The invention is directed to chopped strands of carbon fibers in which 0.3-5% by weight of carbonaceous spherules are present between filaments of carbon fibers. The chopped strands of carbon fibers can be used in spinning. During production, the chopped strands include water, or an organic medium, in which 1-15% by weight of carbonaceous spherules are dispersed. The chopped strands of carbon fibers show no fusion of filaments together, are excellent in separationability and easily disperse in a matrix while maintaining excellent bundling properties.

Abstract: Resin-coated chopped carbon fiber stands for direct injection molding including chopped carbon fiber strands coated with 20-50 parts by weight of a thermosetting resin and 0.5-30 parts by weight of an urethane resin based on 100 parts by weight of the carbon 2iber chopped strands.

Abstract: The present invention provides a short-fiber containing composition inhibited from electrostatic charging and having practical insulating properties. This composition has a volume resistivity of 10.sup.5 -10.sup.13 .OMEGA.cm and comprises 10-40 parts by weight of at least one kind of short fibers having a volume resistivity of 10.sup.-1 -10.sup.3 .OMEGA.cm and 90-60 parts by weight of a polymer or comprises 10-40 parts by weight of a mixture comprising at least one kind of short fibers having a volume resistivity of less than 10.sup.-1 .OMEGA.cm and at least one kind of short fibers having a volume resistivity of 10.sup.-1 .OMEGA.cm or more and 90-60 parts by weight of a polymer. A method for controlling the polymer composition to 10.sup.5 -10.sup.13 .OMEGA.cm in volume resistivity is also provided.

Abstract: The present invention relates to a process for producing a carbon fiber chopped strand which comprises preparing a pitch fiber from petroleum pitch or coal pitch, cutting the pitch fiber to a predetermined desired length, heating the cut pitch fiber at a high density accumulation in the atmosphere of an oxidative gas to infusibilize the cut pitch fiber, and then carbonizing and graphitizing the infusibilized fiber in an inert atmosphere. According to the process of the invention, no fuzz are formed on the fiber and no uneven infusibilization takes place. Further, the pitch fiber chopped strand accumulation has a high bulk density and relieve exothermic excursion naturally, and therefore neither combustion nor sticking takes place even in an oxidative atmosphere. Accordingly, the production speed can be enhanced and the cost can be lowered to a great extent.

Abstract: This invention provides a method for infusibilization of pitch fibers for production of carbon fibers which comprises putting pitch fibers prepared by melt spinning from a spinning pitch in containers, introducing in succession the containers containing the pitch fibers into an infusibilizing furnace divided into a plurality of sections and passing the containers therethrough from inlet to outlet wherein the containers containing the pitch fibers are intermittently moved through the infusiblizing furnace to retain each of the containers in respective sections for a given period of time, during which temperature of respective sections is independently raised from minimum controlled temperature to maximum controlled temperature and thereafter is lowered to the minimum controlled temperature and then the container is moved.

Abstract: Disclosed is a method for producing carbon fiber chopped strands excellent in bundling of fibers, high in bulk density, uniform in fiber length and superior in molding operability which includes application of an inorganic and/or organic binder in an amount of 0.1-3% by weight in terms of solid to carbon fiber or graphite fiber strands or chopped strands made from a petroleum or coal pitch.

Abstract: A flat glass fiber strand comprises a multiplicity of glass filaments having a non-circular cross-sectional shape with the ratio between its maximum and minimum dimensions being between 1.2:1 and 3:1, and which are gathered in such a manner that one dimension of the cross-section of each extends in parallel with the same dimension of the other filaments. This flat glass fiber strand is manufactured by discharging molten glass under high pressure from a multiplicity of nozzles which are shaped in the form of bores having non-circular cross-sectional shape with the ratio between its maximum and minimum dimensions being between 1.5:1 and 6:1 so as to form a multiplicity of filaments of non-circular cross-sectional shape which are then gathered and wound.

Abstract: A method of producing a glass fiber strand in which a plurality of molten glass filaments spun from adjacent nozzle ports in a nozzle plate are adjoined to one another so as to form a single glass fiber having a non-circular cross-sectional shapes such as oval, elliptic, cocoon-shaped and polygonal shapes. The method can employ a nozzle plate provided in the underside thereof with a plurality of recesses in each of which a plurality of nozzle ports are opened, so that the molten glass filaments from these nozzle ports are adjoined to each other so as to form the single glass fiber having a non-circular cross-section.

Abstract: An air nozzle apparatus for directing air flow against the undersurface of an orifice plate of a glass fiber drawing forehearth, having an air introducing section having a manifold formed with at least one air supply port, and an air nozzle section formed with a plurality of nozzle channels communicating with the manifold. The air nozzle section has a plurality of nozzle ribs of substantially the same shape each having opposed side surfaces and opposed end edge portions. The plurality of nozzle ribs are arranged to have their side surfaces located in adjacent relationship to provide a nozzle block. Each nozzle rib is formed on at least one of the opposed side surfaces with a longitudinally extending recess which defines one of the plurality of nozzle channels between the adjacent nozzle ribs.

Abstract: An apparatus and method for manufacturing glass fibers are provided. The apparatus comprises means for containing a head of glass; an orifice plate having a large number of orifices arranged in flooding relationship, each of said orifices being provided on a projection or tip extending downwardly from said orifice plate; and means disposed below said orifice plate and being in communication with a gas supply for directing air upwardly to the undersurface of said orifice plate to cool the cones of glass formed at each projection or tip, said air impinging upon said orifice plate.

Abstract: Disclosed is a bushing for spinning glass fibers having at its bottom an orifice plate provided with a great number of extremely densely disposed plain holes constituting orifices. In order to stiffen the orifice plate, beam members are provided in the bushing to extend substantially in parallel with and spaced from the orifice plate. Each beam member is fixed at its both ends to confronting walls of the bushing, and is connected to the orifice plate by means of rod members having a small diameter.

Abstract: In a glass fiber forming apparatus comprising an orifice plate which has a large number of closely spaced orifices and has a flat undersurface and air is blown upwardly against said orifice plate during spinning operation, means is provided for mechanically separating into individual glass fibers a mass of molten glass adhering to the undersurface of the orifice plate in flooding condition before spinning is started or after all glass fibers are broken. The separating means is a clamping means so constructed and arranged as to clamp a mass of molten glass, means for moving said clamping means between a waiting position at which said clamping means will not interfere with the stream of filaments in the normal spinning operation and an operative position at which said clamping means can clamp a mass of molten glass, and means for causing said clamping means to open or close.

Abstract: The orifice plate 2 in the bottom of a bushing 1 is uniformly inwardly curved in a concave manner, whereby its resistance to outward deformation or sagging under the weight of molten glass in the bushing and the tension of glass filaments 5 withdrawn therethrough is greatly increased. The plate may be rectangular or circular, i.e. arch-shaped or domed, and may be further strengthened by reinforcing bars 7 secured to the interior side walls of the bushing and to the crown portion of the plate.

Abstract: In an apparatus for producing glass fibers wherein an orifice plate formed with a greater number of orifice holes in high density is provided to draw glass fibers therethrough and air nozzle means is provided for impinging air flow against the undersurface of the orifice plate so that the adjacent cones of molten glass formed on the undersurface of the orifice plate may be prevented from coalescing to each other, an air nozzle assembly is provided which includes a plurality of tubular nozzles arranged in such a way that their discharge ports may be arranged in line and in parallel with the longitudinal direction of the array of orifice holes in the orifice plate and spaced apart from each other by a predetermined distance.

Abstract: A method of detecting breakages of glass fiber filaments being drawn through orifies of an orifice plate by converting the variation in intensity of radiant light or heat emitted from a bead of molten glass which grows on the undersurface of the orifices plate at an orifice at which a breakage occurs into an electrical signal by a radiation thermometer which is so arranged as to reciprocate horizontally in parallel with both one side and said undersurface of said orifice plate, whereby the breakage may be detected.

Abstract: Disclosed is an orifice plate for use in glass-fiber spinning having a number of densely arranged orifices. Each orifice has a larger diameter at the inlet side thereof facing the molten glass and a smaller diameter at the outlet side thereof facing the ambient air. The ratio of the larger diameter to the smaller diameter is so selected to fall within a range between 1 : 0.4 and 1 : 0.9. The reduced diameter of the orifices at their outlet side provides sufficiently large space between adjacent orifices at their outlet sides, in spite of the high density at which the orifices are arranged, so that the joining of glass cones suspended from respective orifices is conveniently avoided even after the brims of the orifices are ground by the viscous cooled molten glass.

Abstract: Disclosed is an orifice plate for use in a bushing for spinning glass fibers having a number of orifices each of which consists of two cascaded coaxial cylindrical bores of different diameters, one of which opens in the upper surface of the orifice plate to constitute a molten-glass inlet-side bore, while the other opens in the lower surface of the orifice plate to constitute a molten-glass outlet-side bore.The orifices are so densely arranged as would allow joining of molten glass cones formed at adjacent orifices if a suitable countermeasure such as a cooling by air flow were not taken.

Abstract: In a process for spinning glass fibers continuously from a nozzle plate having 25- 200 orifices per cm.sup.2, a start-up operation is improved by using the nozzle plate made of a material having a contact angle of 60.degree. or more, drawing flooded molten glass which has spread over the whole undersurface of the nozzle plate at a greater speed than the flowing speed of the molten glass by its own weight from each orifice, while maintaining the normal spinning temperature, and finding the ends of the individual filaments.