Abstract: A flexible metal foil-polyimide laminate is prepared by applying a dimethylacetamide solution of polyamic acid onto a metal foil, drying the applied solution to form a semi-dry adhesive layer, laminating a polyimide film thereto on a hot roll press, and heat curing for solvent removal and imidization. The polyimide film has a dimethylacetamide gas permeability of at least 0.1 kg/m2·hr at 5 Torr and 200° C. In the heat curing step, the residual solvent and the water formed upon imidization in the adhesive layer are removed through the polyimide film.

Abstract: A flexible metal foil-polyimide laminate is prepared by joining a polyimide film to a metal foil via an intervening adhesive layer. The adhesive is a mixture of polyamic acids: (A) the reaction product of 3,4,3?,4?-biphenyltetracarboxylic anhydride with p-phenylenediamine, (B) the reaction product of 3,4,3?,4?-biphenyltetracarboxylic anhydride with 4,4?-diaminodiphenyl ether, and (C) the reaction product of pyromellitic dianhydride with 4,4?-diaminodiphenyl ether, in a weight ratio (A+B)/C between 75/25 and 25/75. The method is simple and inexpensive, and yields a flexible metal foil-polyimide laminate that is improved in peel strength and curling resistance while maintaining the heat resistance of polyimide.

Abstract: A flexible metal foil/polyimide laminate is prepared by furnishing a composite film including a polyimide film having a Tg?350° C., sandwiched between polyimide layers having a Tg?300° C., laying metal foils on opposite sides of the composite film, and continuously hot pressing the resulting stack in a vacuum atmosphere having a vacuum of up to 5 Torr or a nitrogen atmosphere having an oxygen concentration of up to 0.5% by volume. A flexible metal foil/polyimide laminate having improved surface properties can be continuously prepared while preventing the metal foils from being degraded by oxidation.

Abstract: An adhesive sheet made of an acrylic adhesive composition comprising (A) an acrylic polymer containing carboxyl groups and having a Tg of 5-30° C., (B) a resol phenolic resin, (C) an epoxy resin, and (D) a curing accelerator has improved heat resistance, processing and handling as well as good adhesion, and is suited for use in the manufacture of FPC.

Abstract: The invention discloses a method for counting foreign matter particles in a vinyl chloride resin powder comprising the steps of: forming an aqueous dispersion of the resin particles in a vessel having a transparent bottom, allowing the particles to settle forming a layer together with the foreign matter particles and viewing the layer of the deposited particles through the transparent bottom of the vessel to count the foreign matter particles in the deposited layer. The invention also provides an apparatus system for automatically counting foreign matter particles which comprises a vessel having a transparent bottom, a feed means for the resin powder, a water supply means, a stirrer means to form an aqueous dispersion in the vessel, a viewing means such as a CCD camera for recording the bottom image of the deposited layer through the transparent bottom of the vessel, and a control means for bringing the various parts of the system into a sequential linkage motion.

Abstract: A polyimide precursor resin solution composition sheet having a solvent content of 1-50% by weight and a thickness of 1-10 microns has improved adhesion, forms a heat resistant polyimide layer when cured, and is advantageously used in the bonding of conductors to plastic films.

Abstract: The invention discloses a method for counting foreign matter particles in a vinyl chloride resin powder comprising the steps of: forming an aqueous dispersion of the resin particles in a vessel having a transparent bottom, allowing the particles to settle forming a layer together with the foreign matter particles and viewing the layer of the deposited particles through the transparent bottom of the vessel to count the foreign matter particles in the deposited layer. The invention also provides an apparatus system for automatically counting foreign matter particles which comprises a vessel having a transparent bottom, a feed means for the resin powder, a water supply means, a stirrer means to form an aqueous dispersion in the vessel, a viewing means such as a CCD camera for recording the bottom image of the deposited layer through the transparent bottom of the vessel, and a control means for bringing the various parts of the system into a sequential linkage motion.

Abstract: A vinyl chloride polymer is prepared by charging a reactor with a vinyl chloride monomer, effecting polymerization, removing a slurry of the polymer from the reactor, and washing the reactor interior with water, and repeating the series of steps. The reactor has an internal volume of at least 40 m3. A cylinder-guided lift type washer assembly having a nozzle is secured to the reactor at its top in a sealed manner such that the nozzle can be moved downward and upward in the reactor. Water is fed to the nozzle through the assembly for injecting water from the nozzle into the reactor for cleaning. The large size reactor can be effectively washed with water in the closed state, and vinyl chloride polymers of quality with least fisheyes are produced batchwise, leading to an improved productivity.

Abstract: A process for producing a vinyl chloride polymer for matted moldings which comprises performing the suspension polymerization of vinyl chloride monomer or a mixture of vinyl monomers composed mainly of vinyl chloride in an aqueous medium, said suspension polymerization being performed after the addition of a dispersion obtained by dispersing a polyfunctional monomer having 2 or more ethylenic double bonds in the molecule into a solution containing a partially saponified polyvinyl alcohol having a degree of saponification of 25 to 65 mole % and an average degree of polymerization of 150 to 1000, thereby yielding a vinyl chloride resin composed of 5 to 90 wt % tetrahydrofuran-insoluble gel fraction, with the remainder being tetrahyrofuran-solubles.

Abstract: An improvement is proposed in the process of suspension polymerizatiopn of vinyl chloride monomer in an aqueous polymerization medium, by which a resin product of high quality relative to the contents of foamy resin and fish-eyes can be produced in a high efficiency with little deposition of polymer scale on the reactor walls. The improvment comprises heating and keeping the surfaces of the polymerization reactor and accessory equipment coming into contact with the gaseous phase above the polymerization mixture at a temperature of 55.degree. C. or higher during a period starting from a moment when the temperature of the polymerization mixture under temperature elevation up to the polymerization temperature is still 45.degree. C. or lower to a moment when conversion of the monomer into polymer is at least 10% so that foaming on the polymerization mixture can be greatly reduced.

Abstract: A process for preparing a vinyl chloride polymer of the present invention comprises initiating suspension polymerization by suspending a vinyl chloride monomer in an aqueous medium in the presence of a first dispersion stabilizer and adding a second dispersion stabilizer at a specified time after the initiation of polymerization. Here, as the first dispersion stabilizer, (A) a partially saponified polyvinyl alcohol with a high saponification degree and (B) a hydroxypropylmethyl cellulose are used in combination, and as the second dispersion stabilizer, (C) a partially polyvinyl alcohol with a low saponification degree is used. According to the process, it is possible to prepare a vinyl chloride polymer with excellent characteristics such as plasticizer take-up, etc.

Abstract: A process for producing a vinyl chloride polymer for matted moldings which comprises performing the suspension polymerization of vinyl chloride monomer or a mixture of vinyl monomers composed mainly of vinyl chloride in an aqueous medium, in the presence of (A) 0.01 to 3 parts by weight of a polyfunctional monomer having two or more ethylenic double bonds in the molecule and (B) 0.00005 to 0.01 part by weight of antioxidant, thereby yielding a vinyl chloride resin composed of 5 to 90% by weight of tetrahydrofuran-insoluble gel fraction, with the remainder being tetrahydrofuran-solubles.

Abstract: A process for preparing a vinyl chloride polymer, which comprises polymerizing vinyl chloride or a monomeric mixture composed mainly of vinyl chloride in an aqueous medium, wherein the polymerization reaction is terminated at the last stage of polymerization by addition of an aqueous dispersion of an antioxidant, containing a polyoxyalkylene glycol as a dispersing agent. A polymer with good initial coloration characteristic, thermal stability and take-up of plasticizer, and large bulk density can be obtained.

Abstract: A process of producing a vinyl chloride polymer, comprising the step of suspension polymerizing vinyl chloride or a monomer mixture comprising mainly vinyl chloride in the presence of an oil-soluble polymerization initiator in an aqueous medium containing a dispersant, wherein said dispersant comprises:(A) a partially saponified polyvinyl alcohol,(B) a hydroxypropylmethyl cellulose, and(C) a crosslinked polymer having a carboxyl group.This process can produce a vinyl chloride polymer having a high bulk density and a high porosity and therefore capable of producing an extruded product with an extremely small amount of fish eyes, at high efficiency and high productivity.

Abstract: The invention provides an improved method for the suspension polymerization of vinyl chloride to give a polyvinyl chloride resin having excellent properties such as high bulk density, small number of fish-eyes, rapid plasticizer absorption and easy monomer releasability with a decreased amount of polymer scale deposition on the reactor walls. The inventive method characteristically comprises the successive steps of: introducing water as the suspension medium at an elevated temperature of 40.degree. C. or higher, introducing the monomer under agitation to be dispersed into monomer droplets, introducing a partially saponified polyvinyl alcohol, which satisfies several specific physical and chemical requirements, in the form of an aqueous solution and, within 3 minutes thereafter, introducing a monomer-dsoluble polymerization initiator.

Abstract: A process for producing a vinyl chloride polymer for matted moldings which comprises performing the suspension polymerization of vinyl chloride monomer or a mixture of vinyl monomers composed mainly of vinyl chloride in an aqueous medium, said suspension polymerization being performed after the addition of an aqueous dispersion obtained by dispersing a polyfunctional monomer having 2 or more ethylenic double bonds in the molecule into an aqueous solution of a water-soluble partially saponified polyvinyl alcohol, a water-soluble cellulose eter or an emulsifier, thereby yielding a vinyl chloride resin composed of 5 to 90 wt % tetrahydrofuran-insoluble gel fraction, with the remainder being tetrahydrofuran-solubles.

Abstract: Such food packing materials as heat shrinkable films or such formed containers for food as bottles are manufatured by forming resin compositions of the following compostions: (a) 100 weight parts of vinyl chloride based resin obtained by adding 0.005 to 0.5 weight parts of partially saponified polyvinyl alcohol, degree of saponification 20-55 mol %, means degree of polymerization 150-600, to 100 weight parts of loaded vinyl chloride monomer or a mixture of vinyl based monomer with vinyl chloride as main, during suspension-polymerizing in an aqueous medium under the existence of 0.03-0.08 weight parts of partially saponified polyvinyl alcohol, degree of saponification 65-80 mol %, means degree of polymerization 600-1000, or else in slurry after completion of the suspension-polymerizing: (b) 0.3 to 5 weight parts of non-toxic stabilizer for food which is a liquid composite stabilizer; and (c) 4 to 15 weigth parts of butadiene-styrene based copolymer resin.

Abstract: A method for preparing vinyl chloride polymers which comprises polymerizing vinyl chloride monomer or a vinylic monomer mixture mainly composed of vinyl chloride in an aqueous medium in the presence of a polymerization initiator, characterized by washing a piping and an opening of a polymerizer, for charging the polymerization initiator into the polymerizer, with water, steam or a washing liquid capable of lowering the half-life of the polymerization initiator to not more than 30 minutes after introducing the initiator into the polymerizer. The method makes it possible to eliminate the formation of polymer scales on the piping and the opening for charging the polymerization initiator into a polymerizer and, therefore, the yield of the vinyl chloride polymers can greatly improved and the production cost can be substantially saved. Moreover, the polymer product does not include any materials used for washing said portions and thus polymer product of high quality can be provided in a high yield.

Abstract: A process for preparing a vinyl chloride polymer comprises initiating suspension polymerization with a monomer, etc. being suspended previously in an aqueous medium by used of (A) a particular partially saponified polyvinyl alcohol with high saponification degree and (B) a particular hydroxypropylmethyl cellulose as the first dispersion stabilizer, and adding further the partially saponifice polyvinyl alcohol (A) into the polymerization system at a predetermined timing after the initiation of polymerization. A vinyl chloride polywer with a high bulk density can be obtained, and yet from said polymer, a molded or formed product of high quality with a very small number of fish eyes can be obtained.

Abstract: A highly heat-resistant and thermally stable polyvinyl chloride resin can be prepared by copolymerizing vinyl chloride monomer and an N-substituted maleimide compound without decreasing the ingerently excellent properties of polyvinyl chloride resins when the monomer mixture is suspension-copolymerized in an aqueous medium containing a suspending agent which is a combination of three different polymers including: (a) a first partially saponified polyvinyl alcohol having an average degree of polymerization in the range from 700 to 3000 and a degree of saponification in the range from 70 to 95%; (b) a second partially saponified polyvinyl alcohol having an average degree of polymerization in the range from 300 to 600 and a degree of saponification in the range from 35 to 55%; and (c) a water-soluble cellulose derivative of which a 0.2% by weight aqueous solution has a surface tension not exceeding 55 dyn/cm at 25.degree. C., in a specified proportion.