Abstract: The object of the present invention is to provide a method capable of producing polyimide resins having excellent heat resistance, which can utilize inexpensive monomers and does not use solvents. The method comprises mixing, in the absence of a solvent, a diamine and at least one tetracarboxylic acid component selected from the group consisting of a tetracarboxylic acid, a tetracarboxylic acid monoanhydride and a tetracarboxylic acid dianhydride capable of forming two imide rings upon cyclization, and then heat-treating the mixture.

Abstract: The object of the present invention is to provide a method capable of producing polyimide resins having excellent heat resistance, which can utilize inexpensive monomers and does not use solvents. The method comprises mixing, in the absence of a solvent, a diamine and at least one tetracarboxylic acid component selected from the group consisting of a tetracarboxylic acid, a tetracarboxylic acid monoanhydride and a tetracarboxylic acid dianhydride capable of forming two imide rings upon cyclization, and then heat-treating the mixture.

Abstract: There are provided a process for producing a two-layered tape for TAB, which comprises forming desired holes in a semi-cured polyamic acid film formed on a release film or in a semi-cured polyamic acid film subjected to stretching of 10% or more, then pressure-bonding the resulting film or film laminate to a conductor foil or a conductor foil on which a semi-cured light-transmittable polyamic acid film is formed, so that the polyamic acid film and the conductor foil contact with each other or the two polyamic acid films contact with each other, conducting imidization, and thereafter forming a desired pattern in the conductor foil; a process for producing a stretched polyamic acid film by subjecting a polyamic acid film to stretching of 10% or more; and a process for producing a flexible base board for printed circuit or a flexible printed circuit board with a cover layer, both using said stretched polyamic acid film.

Abstract: An information recording/reproducing apparatus is provided with a shutter mechanism for closing and opening an insertion slot formed on a wall of a housing to insert/eject an information recording medium into/from the housing. The shutter mechanism includes a first member which is movable in a first direction perpendicular to a second direction in which the information recording medium is inserted into the slot of the housing, the first member being movable between a slot open and a slot closed position. A second member is fixed on the housing and is selectively either contacting the first member in the slot closed position or being spaced away from the first member in the slot open position. A slanted surface, which is slanted or inclined with respect to the first and the second directions, is formed on the first member such that the first and second members contact each other on the slanted surface when the first member is in the slot closed position.