Abstract: An apparatus for manufacturing multilayer hollow articles having sections different from one another in respect to the kinds of resins, number of layers, and thickness of layers along the circumference in the horizontal section of an article with the narrowest of the sections in any one of the resin layers extending in a specified width along the longitudinal wall of an article and being capable of satisfying the sectional performance requirements. An apparatus is provided for manufacturing multilayer hollow articles with the wall thickness ratio of resin layers in each section varying along the longitudinal wall of an article or those with the sectional width in each resin layer varying along the longitudinal wall of an article. Hollow articles molded by the apparatus of this invention are particularly useful for automotive bumpers, the seats and backs of chairs, and boiler-room doors.

Abstract: Ortho spiroesters of excellent heat resistance and low volume shrinkage during curing are disclosed. Resin compositions of excellent heat resistance and low curing shrinkage containing these ortho spiroesters are also provided. These photosensitive or heat-curable resin compositions are formulated from photo- or heat-polymerizable compounds containing ethylenic double bonds and carboxyl groups, photopolymerization initiators and sensitizers, or polymerization initiators which generate radicals by heat, and said ortho spiroesters. These resin compositions have low curing shrinkage and are useful for applications requiring dimensional accuracy such as molding materials, encapsulants, adhesives and coatings and also for the preparation of image-forming materials such as protective films for color filters, inks and electrically insulating spacers for touch panels.

Abstract: This invention relates to heat-resistant film adhesives for use in fabrication of printed circuit boards formulated from polyimides with silicone units and epoxy resins and, if necessary, epoxy resin curing agents. It is possible to introduce functional groups reactive with epoxy resins into the polyimide structure. The films are used by inserting them between adherends and pressing at 1 to 1,000 kg/cm.sup.2 and 20.degree. to 250.degree. C. and they show excellent heat resistance, heat resistance at soldering temperature after moisture absorption and processibility when contact-bonded at 250.degree. C. or less.

Abstract: This invention provides a blow molding process for manufacturing multilayer hollow articles having sections different from one another in respect to the kind of resins, number of layers, and thickness of layers along the circumference in the horizontal section of an article with the narrowest of the sections in any one of the resin layers extending in a specified width along the longitudinal wall of an article and being capable of satisfying the sectional performance requirements, an apparatus, and said hollow articles. It also provides a process for manufacturing multilayer hollow articles with the wall thickness ratio of resin layers in each section varying along the longitudinal wall of an article or those with the sectional width in each resin layer varying along the longitudinal wall of an article, an apparatus, and said hollow articles.

Abstract: A mold 11 having an inner surface coated with a heat insulating film 14 excellent in heat insulation and conformability to a molten resin 20 is clamped with the other mold 12 to form a molding cavity 13. When the molten resin 20 is cooled and solidified in the cavity 13, heat transmission through the mold 11 is suppressed by the film 14 so that a skin layer 23 preferentially grows at the side of the mold 12. Hence, the volumetric shrinkage of the resin 20 during cooling and solidification is selectively absorbed in the deformation of the skin layer 23 separated from the inner surface of the mold 12. As a result, an obtained product has a smooth front surface free from defects such as sink marks. The heat insulating film 14 exhibits the effect to eliminate weld lines, too.

Abstract: A laminate comprising at least two layers of a photosensitive resin layer and a polyimide precursor resin layer; a process for formation of an insulating protective layer using a laminate which comprises laminating a laminate comprising at least photosensitive resin layer and a polyimide precursor resin layer on an insulating board having an exposed circuit; selectively exposing the photosensitive resin layer to active light; developing the resultant photosensitive resin layer; removing the exposed polyimide precursor resin layer by etching it with an alkaline solution using the photosensitive resin layer as a mask; removing the photosensitive resin layer; and then curing the residual polyimide precusor resin layer; and a process for preparation of a printed circuit which comprises forming a polymide precursor resin layer on an insulating board having an exposed circuit, patterning the resin layer with an alkaline solution, and then curing it.

Abstract: A method for producing carbon fiber comprising applying an infusibilization to a pitch fiber yarn made using mesophase pitch as a starting material in a state with substantially no tension applied to the yarn and in an oxidizing gas atmosphere including nitrogen dioxide and oxygen, then sintering in an inert gas atmosphere of 350.degree. C. to less than 400.degree. C. for 10 minutes or more for primary carbonization, then applying secondary carbonization at a temperature of 800.degree. to 1300.degree. C. for 5 to 120 seconds, while feeding out the yarn in the linear form and continuously transporting the same.

Abstract: A pitch-based carbon fiber reinforced composite material is improved with regard to its compressive strength and compression strain at failure by combining polyacrylonitrile-based carbon fibers. The pitch-based carbon fibers have a modulus in tension of not less than 400 GPa, a tensile strength of not less than 2000 MPa, a compressive strength as a unidirectionally reinforced composite material of 100 MPa to 800 MPa and a fiber diameter of 4 .mu.m to 15 .mu.m and the polyacrylonitrile-based carbon fibers have a modulus in tension of not less than 200 GPa, a compressive strength and compression strain at failure as a unidirectionally reinforced composite material larger than those of the pitch-based carbon fibers, and a fiber diameter smaller than that of the pitch-based carbon fibers.

Abstract: This invention relates to a solar heat-shielding coating composition which consists mainly of two kinds or more of pigments selected from red, orange, yellow, green, blue and purple pigments in such a manner as to yield a color of low lightness, particularly achromatic black, by additive mixture and a weather-resistant vehicle and a structure covered with said coating composition, with the composition capable of covering the outside of said structure exposed directly to the sun and suppressing a rise in the inside temperature.

Abstract: When injection-molding a molten thermoplastic resin into a molding having different thicknesses, a void inducing member is set in a cavity corresponding to heavy sections. Then gas pressure is applied passing through a gas passageway to a tip end of the void inducing member, thus forming a void nucleus in the resin adjacent to the tip end of the void inducing member. The void nucleus develops to a void by shrinking force of the resin as the molten resin cools.

Abstract: This invention provides a blow molding process for manufacturing multilayer hollow articles having sections different from one another in respect to the kind of resins, number of layers, and thickness of layers along the circumference in the horizontal section of an article with the narrowest of the sections in any one of the resin layers extending in a specified width along the longitudinal wall of an article and being capable of satisfying the sectional performance requirements, an apparatus, and said hollow articles. It also provides a process for manufacturing multilayer hollow articles with the wall thickness ratio of resin layers in each section varying along the longitudinal wall of an article or those with the sectional width in each resin layer varying along the longitudinal wall of an article, an apparatus, and said hollow articles.

Abstract: A bundle of pitch-based carbon fibers which is composed of 1000 to 100,000 continuous fiber filaments having an average diameter of 4 to 8 .mu.m, a filament tensile strength of at least 3.0 GPa, and a modulus of at least 600 GPa, and also a method for producing a fine diameter pitch-based carbon fiber wherein use is made of a spinning nozzle with a single nozzle plate which has at least 1000 capillary holes, has the capillaries arranged concentrically and circularly in 3 to 20 rows, has the capillaries positioned to be divided into at least two blocks, has a columnar projection protruding at least 20 mm from the surface of the nozzle plate at the center of the nozzle plate, and has capillaries of a diameter of 50 to 110 .mu.m.

Abstract: In the recovery of dehydrogenation oil from the reaction product gas from the vapor-phase catalytic dehydrogenation of diethylbenzene by condensing the gas in a condenser, this invention relates to a process for preparing divinylbenzene by spraying a high-boiling oil or a high-boiling oil and water inside the condenser and letting the oil or the oil and water contact the reaction product gas and the process is capable of dehydrogenating diethylbenzene at high levels of conversion and selectivity without blocking of the condenser and yielding divinylbenzene of high concentration efficiently in a long-term stable continuous operation.

Abstract: A graphitized fiber heat-treated at a temperature higher than 2300.degree. C. in an inert atmosphere, of which oxidation weight reduction rate A in dry air at 650.degree. C. is in the range defined by the equation (1), of which BET specific surface area S determine by nitrogen or krypton adsorption technique at -196.degree. C. is in the range defined by the equation (2), and of which pore volume determined by the carbon dioxide adsorption technique at 25.degree. C. is 0.001 ml/g or less: ##EQU1## where, A is the oxidation weight reduction rate in dry air at 650.degree. C. in min.sup.-1S is the specific surface area determine by nitrogen or kypton adsoprtion technique at -196.degree. C. in m.sup.2 g.sup.-1D is the mean monofilament diameter of the graphitized fiber in .mu.m and .rho. is the density of the graphitized fiber in gcm.sup.-3.

Abstract: The invention relates to a process for preparing prilled bisphenol A by granulation which comprises adding compounds soluble in molten bisphenol A, not affecting adversely the melt color of bisphenol A to any significant extent, and have a melting point of 60.degree. C. or more to bisphenol A and granulating and also to a process which comprises adding the reaction mother liquor or cyrstallization mother liquor produced in the manufacturing step of bisphenol A to bisphenol A or the adduct of bispheol A and phenol or a mixture of bispheol A and phenol, removing the phenol, and granulating. The processes yield prilled bispheol A which have high strength and resist powdering.

Abstract: Rubber-modified styrene resins with excellent impact resistance are prepared by formulating a feed from a styrene-based monomer, or a mixture thereof with comonomers and high-viscosity rubber, an organic peroxide, and, if necessary, all inert organic solvent, preheating and continuously supplying the feed to one end of a plug flow type reactor equipped with an agitator, performing the preliminary polymerization to a conversion sufficiently high for the transformation of the rubber in the feed into particles while controlling the weight average particle diameter of the rubber particles to 0.8 to 5 .mu.m, withdrawing the prepolymerized feed from the other end of the reactor, and supplying it to a following plug flow type reactor for continuous enhancement of tile conversion.

Abstract: 2-Alkyl-6-ethylnaphthalene is prepared selectively and efficiently by the reaction of at least one kind of feed naphthalene selected from naphthalene and 2-alkylnaphthalenes with polyethylbenzenes at 50.degree. to 400.degree. C. in the presence of a solid acid catalyst.

Abstract: A process is disclosed for preparing of aromatic polyester-polystyrene block copolymers which comprises subjecting preferentially styrene polymers (A) having terminal functional groups reactive with acid chloride groups and an excess of aromatic dicarboxylic acid dihalides (C) to condensation and then subjecting continuously the resultant mixture and aromatic dihydroxy compounds (B) to interfacial polymerization at the ratio (A)/[(B)+(C)] by weight of 5/95 to 80/20, without separating reaction products of styrene polymers (A) and aromatic dicarboxylic acid dihalides (C), and the block copolymers thus prepared contain a small amount of uncopolymerized styrene polymers, have long aromatic polyester segments, show low birefringence, good transparency, exceptionally low birefringence, low melt viscosity, and good mechanical strength, and are particularly useful as materials for optical instruments.

Abstract: This invention provides a method for separating 2,6-diethylnaphthalene from a mixture of diethylnaphthalene isomers by contacting said mixture with zeolite producing the same powder X-ray diffraction pattern as faujasite and the method can efficiently separate 2,6-diethylnaphthalene from ethylation reaction products containing diethylnaphthalene isomers.

Abstract: This invention relates to a process for preparing bisphenol A of good heat stability by heat-treating bisphenol A containing a very small amount of impurities in a molten state at 185.degree. to 220.degree. C. for 5 to 60 minutes in an oxygen-free atmosphere and the process yields bisphenol A of good heat stability which shows reduced coloration when heated. Bisphenol A prepared by this process has excellent properties relating to color and is particularly suitable as raw material for the manufacture of polycarbonates where the requirement for color is strict.