Abstract: A hot air heater includes heating wires (3a, 3b) wound around an insulating fire-resistant support in such a way that currents flow reversely through the heating wires (3a, 3b) in order to compensate electromagnetic waves generated from the heating wires (3a, 3b), thus reducing electromagnetic waves.

Abstract: This invention provides an unheated-curable binder composition and a method for manufacturing a phenolic resin molded article using the binder. This invention also provides a porous ceramic molded article obtainable by setting a ceramic and the above-mentioned binder composition under unheated conditions to give a set article and then baking the set article, and a method for manufacturing the article. This invention also provides an unheated-curable binder composition having as its main components a crosslinking agent, a catalyst, and a trifunctional or tetrafunctional phenol bearing one or two electron donating groups on the benzene ring of the phenol, and a method for manufacturing a phenolic resin molded article using the binder.

Abstract: The present invention provides a method of manufacturing an exfoliated graphite/phenol resin composite foam of a porosity of 50-95%, a density of 0.1-0.8 g/cm3, by forming under contact pressure or reduced pressure at a temperature of 140-200° C. a mixture comprising 100 parts by weight of powdered and/or crushed exfoliated graphite and 40-240 parts by weight of phenol resin; an exfoliated graphite/phenol resin composite foam obtained by the method; and a method of obtaining an exfoliated graphite/glassy carbon composite foam of a porosity of 50-95%, a density 0.1-0.8 g/cm3 with volumetric baking shrinkage of 10% or less by baking the exfoliated graphite/phenol resin composite foam.

Abstract: A carbon heating element of excellent durability and thermal shock resistance, usable even in a special environment, for example, even in a strong oxidizing chemical, and having a sufficient capability of generating heat with smaller power consumption. The carbon heating element is formed by covering a carbon material, such as carbon fiber or a carbon fiber cloth with quarts glass, making the interior of the quartz glass vacuous or setting the pressure of the interior of the quartz to not higher than 0.2 atm. with substituted inert gas, and melt-scal the quartz glass.

Abstract: The present invention provides a method of manufacturing an exfoliated graphite/phenol resin composite foam of a porosity of 50-95%, a density of 0.1-0.8 g/cm3, by forming under contact pressure or reduced pressure at a temperature of 140-200° C. a mixture comprising 100 parts by weight of powdered and/or crushed exfoliated graphite and 40-240 parts by weight of phenol resin; an exfoliated graphite/phenol resin composite foam obtained by the method; and a method of obtaining an exfoliated graphite/glassy carbon composite foam of a porosity of 50-95%, a density 0.1-0.8 g/cm3 with volumetric baking shrinkage of 10% or less by baking the exfoliated graphite/phenol resin composite foam.

Abstract: This invention relates to a granular phenolic resin forming material. Grains are obtained by pulverizing a hardened phenol resin or epoxy resin, particularly a waste, having aromatic rings. The grains are heated to react with a phenolic substance, to solubilize at least surfaces thereof, whereby the grains are made formable again. The pulverized, hardened grains and the phenolic substance, preferably a phenol, are mixed in the ratio of 100/10 to 100/90. An acid catalyst may be used, as necessary, in a quantity not exceeding 9 parts. A preferred reaction temperature is 80.degree. to 180.degree. C. at atmosphere pressure. The forming material of this invention may be formed with hexamine compounded therewith.