Abstract: The invention generally relates to a flexible heal exchanger comprising a pair of flexible multilayer thermoplastic polyimide films each of which comprises an aromatic polyimide substrate film showing no glass transition temperature or a glass transition temperature of 340° C. or higher and a thermoplastic aromatic polyimide surface film showing a glass transition temperature in the range of 190 to 300° C. in which the surface films of the flexible multilayer thermoplastic polyimide films face each other and are in part fused together, whereby producing between the flexible multilayer thermoplastic polyimide films a conduit pattern through which a fluid passes. The flexible multilayer thermoplastic polyimide films preferably have a thickness in the range of 10 to 125 ?m and comprise a linear expansion coefficient of MD, a linear expansion coefficient of TD and an average of linear expansion coefficients of MD and TD, in the range of 10×10?6 to 35×10?6 cm/cm/° C. at 50-200° C.

Abstract: A polyimide powder for an antistatic polyimide molded product is disclosed. The polyimide powder comprises a polyimide-powder prepared from an aromatic tetracarboxylic acid component and a diamine component, and a conductive carbon black having a DBP oil absorption of 300 ml/100 g or more; wherein the amount of the conductive carbon black is within a range of 0.75 wt % to 5 wt % relative to the polyimide-powder. A polyimide molded product with sufficient antistatic property can be formed by molding the above polyimide powder.

Abstract: A terminal-crosslinkable polyamic acid oligomer having 1) heat resistance indicated by Tg of 300° C. or more and a pyrolysis temperature of 500° C. or more, 2) toughness, and 3) capability of allowing an increase in concentration. The polyamic acid oligomer is obtained by reacting an aromatic tetracarboxylic dianhydride including 2,2?,3,3?-biphenyltetracarboxylic dianhydride, an aromatic diamine compound, and a reactive crosslinking agent including an amino group or acid anhydride group and a crosslinkable group in the molecule, and includes a crosslinkable group at the molecular terminal.

Abstract: A water-soluble polyimide precursor, which can be suitably applied for aromatic polyimides and exhibits a low reduction in heat resistance and mechanical properties, an aqueous solution of the polyimide precursor and a polyimide obtained from the precursor. A heat-resistant fiber impregnated material and an impregnated sheet-like material are prepared by using the precursor and a laminate is prepared by employing the precursor.

Abstract: Machines existing in a plant are classified under a multilevel hierarchy and are displayed on a screen. A summary of a diagnosis result of one or more nondisplayed machines which is not displayed on the screen and is classified to a level lower than that of the machines displayed on the screen. Therefore, the diagnosis result of the nondisplayed machines can also be seen on the screen and oversights of machine management can be prevented.

Abstract: A terminal-crosslinkable polyamic acid oligomer having 1) heat resistance indicated by Tg of 300° C. or more and a pyrolysis temperature of 500° C. or more, 2) toughness, and 3) capability of allowing an increase in concentration. The polyamic acid oligomer is obtained by reacting an aromatic tetracarboxylic dianhydride including 2,2?,3,3?-biphenyltetracarboxylic dianhydride, an aromatic diamine compound, and a reactive crosslinking agent including an amino group or acid anhydride group and a crosslinkable group in the molecule, and includes a crosslinkable group at the molecular terminal.

Abstract: A flexible heating sheet is composed of two heat fusible aromatic polyimide films and an electric heating element having an electric source-connecting terminal at each end which intervenes between the heat fusible aromatic polyimide films, in which each heat fusible aromatic polyimide film is covered with a heat resistant aromatic polyimide film.

Abstract: A foamed polyimide shaped article having heat resistance and molded to any shape obtained by molding and then calcining a mixture of pulverized pieces of a pre-foamed polyimide resin mass and a heat resistant binder and a process for production of the same comprising pulverizing a pre-foamed polyimide resin mass, mixing the pulverized pieces with a heat resistant binder, molding the mixture to a predetermined shape, then calcining it at a temperature of at least 350° C. to cure the binder and strongly bond the polyimide foam mass.

Abstract: A flexible polyimide foam having an apparent density of 13.5 to 900 kg/m3 and a glass transition temperature of 300° C. or higher can be prepared by mixing an aromatic tetracarboxylic acid comprising 2,3,3′,4′-biphenyltetracarboxylic dianhydride a portion of which is converted into its mono- or di-lower primary alcohol ester with an aromatic polyamine containing diaminodisiloxane in an amount of 0.1 to 10 mol. %, based on the amount of total amine compounds, to give a solid of polyimide precursor; heating the solid of polyimide precursor to a temperature of 300° C. to 500° C. to produce a polyimide foam; and compressing the polyimide foam.

Abstract: A fusible polyimide showing a fusion endothermic peak in a differential scanning calorimeter has a recurring unit of the following formula (1): in which Ar1 is a mixture of residues of tetracarboxylic dianhydrides composed of 12-25 mol. & of a residue of pyromellitic dianhydride, 5-15 mol. % of a residue of 3,3′4,4′-benzophenonetetracarboxylic dianhydride, and a remaining mol. % of a residue of 3,3′,4,4′-biphenyltetracarboxylic dianhydride, and Ar2 is an aromatic diamine residue composed of 1,3-bis(4-aminophenoxy)benzene.

Abstract: An antistatic film with a surface resistivity of 1013 &OHgr;/□, comprising a metal oxide and conductive ultrafine particle mixed layer formed on the surface of a film, and a process for manufacture of the antistatic film which comprises coating the surface of a self-supporting film, obtained by casting and drying a solution of a heat-resistant resin precursor, with a mixture obtained by uniformly combining a metal compound which converts to a metal oxide upon heating, conductive ultrafine particles and a solvent, and then heating it to dryness, removing the solvent and cyclizing the heat-resistant resin precursor. The film exhibits improved antistatic retention with no reduction in its original mechanical properties and formed without the use of special equipment such as a sputtering apparatus, as well as a process for its manufacture.

Abstract: A flexible heat exchanger is composed of a pair of flexible thermoplastic polymer films which are in part fused together, whereby producing between the polymer films a conduit pattern through which a fluid passes.

Abstract: A fusible polyimide showing a fusion endothermic peak in a differential scanning calorimeter has a recurring unit of the following formula (1): 1

Abstract: A flexible polyimide foam having an apparent density of 13.5 to 900 kg/m3 and a glass transition temperature of 300° C. or higher can be prepared by mixing an aromatic tetracarboxylic acid comprising 2,3,3′,4′-biphenyltetracarboxylic dianhydride a portion of which is converted into its mono- or di-lower primary alcohol ester with an aromatic polyamine containing diaminodisiloxane in an amount of 0.1 to 10 mol. %, based on the amount of total amine compounds, to give a solid of polyimide precursor; heating the solid of polyimide precursor to a temperature of 300° C. to 500° C. to produce a polyimide foam; and compressing the polyimide foam.

Abstract: A water-soluble polyimide precursor, which can be suitably applied for aromatic polyimides and exhibits a low reduction in heat resistance and mechanical properties, an aqueous solution of the polyimide precursor and a polyimide obtained from the precursor. A heat-resistant fiber impregnated material and an impregnated sheet-like material are prepared by using the precursor and a laminate is prepared by employing the precursor.

Abstract: In a heat-resistant aromatic polyimide/metal (or metal oxide) composite sheet composed of an aromatic polyimide film and a metal or metal oxide layer arranged on the film, the polyimide film is composed of an aromatic polyimide resin and an Al-containing material dispersed in the polyimide resin in an amount of 1 to 1,000 ppm per the amount of polyimide film, and the metal or metal oxide layer is formed on the polyimide film via no adhesive.