Abstract: An object of the present invention is to provide a method for producing a heat-treated liquid crystal polyester-impregnated base material, which can prevent welding to a supporting material upon a heat treatment. A second liquid crystal polyester-impregnated base material is obtained by heat-treating a first liquid crystal polyester-impregnated base material 11 arranged on a supporting material 13 through a resin layer 12 which exhibits a melting point of 320° C. or higher by the measurement using a differential scanning calorimeter, or does not undergo decomposition at lower than 320° C. and also does not exhibit a melting point.

Abstract: An object of the present invention is to provide a method for producing a heat-treated liquid crystal polyester-impregnated base material, in which the portion to be practically used as the liquid crystal polyester-impregnated base material after a heat treatment is not welded to the supporting member. In the step of heat-treating a first liquid crystal polyester-impregnated base material, the first liquid crystal polyester-impregnated base material is heat-treated while supporting by a supporting member in the site other than the portion to be practically used after the heat treatment to obtain a second liquid crystal polyester-impregnated base material.

Abstract: The present invention provides a process for producing a glass cloth substrate including: an impregnating step of impregnating a surface-treated glass cloth with a liquid composition including a solvent and a polyester to obtain a liquid composition-impregnated glass cloth, and a substrate preparing step of removing the solvent from the liquid composition in the liquid composition-impregnated glass cloth to obtain a glass cloth substrate. According to the present invention, adherability between the liquid crystal polyester and the glass cloth is improved, and the heat resistance at moisture absorption of the glass cloth substrate is improved.

Abstract: A resin-impregnated sheet obtained by impregnating a fiber sheet with a thermoplastic resin, wherein a weight loss rate upon a heat treatment at 225° C. for 30 minutes is from 6.8 to 10% by mass; and a method for producing a resin-impregnated sheet laminate with a metal foil, which comprises preliminarily pressing a plurality of the resin-impregnated sheets while being laid one upon another, subjecting the obtained resin-impregnated sheet laminate to a heat treatment, and arranging a metal foil on both sides of the sheet laminate, followed by regular pressing.

Abstract: The present invention aims at providing a liquid composition which contains a liquid crystal polyester, a solvent and an inorganic filler and which provides a liquid crystal polyester-impregnated fiber sheet that is less likely to cause a decrease in strength even when exposed to high humidity; according to a preferred embodiment, the liquid composition is prepared by mixing a liquid crystal polyester, a solvent, and a surface treated silica containing silica having a volume average particle diameter of from 0.1 to 1.5 ?m, the surface of which is treated with a silane compound having at least one kind of group selected from the group consisting of a methacryloyloxy group, a phenyl group, a vinyl group and an epoxy group.

Abstract: The present invention provides a method for producing a metal foil laminate, the method comprising sequentially interposing an insulating base material between a pair of metal foils and between a pair of metal plates, followed by heating and pressurizing to produce a metal foil laminate in which the pair of metal foils are attached on both sides of the insulating base material, wherein the ratio of an area of the insulating base material to that of each metal plate is from 0.75 to 0.95. According to the present invention, tight adhesion of a metal foil laminate is sufficiently increased even if the metal foil laminate has a large size.

Abstract: A method for producing a liquid crystalline polyester impregnated fiber sheet, comprising a step of impregnating a fiber sheet composed of an aramid fiber or a polybenzazole fiber with a liquid composition containing a liquid crystalline polyester and an aprotic solvent free of a halogen atom and a step of removing the solvent from the fiber sheet impregnated with the liquid composition. As the above mentioned solvent, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone are preferably used. As the above mentioned sheet, textiles are preferably used.