Abstract: A process for producing a vinyl chloride-based polymer by suspension polymerization is provided. The polymerization is initiated in the presence of (A) a particular hydroxypropylmethylcellulose, (B) a particular partially saponified PVA with a saponification degree of 75 to 85 mol % and an average polymerization degree of 1000 to 3000, and (C) a particular partially saponified PVA with a saponification degree of 20 to 57 mol % and an average polymerization degree of 150 to 600 in a specified ration, and said (C) is also additionally added to the polymerization system when a conversion rate is 15–50%. Polymers with a high porosity, excellent plasticizer absorption, extremely low levels of fish eyes, and a high bulk specific gravity are produced at a high level of productivity.

Abstract: In a flexible metal foil/polyimide laminate comprising in sequence, a heat resistant polyimide film, an adhesive layer, and a metal foil, the adhesive layer is a polyimide adhesive layer with a Tg of at least 400° C., obtained by heat imidization of a polyamic acid varnish containing 5-200 ppm of a leveling agent, typically polyether-modified silicone. This laminate of the all polyimide type takes full advantage of the properties of heat resistant polyimide film, includes the adhesive layer having a smooth surface, and is free of thickness variations.

Abstract: A production process for a vinyl chloride polymer is proposed in which either vinyl chloride, or a monomer mixture comprising vinyl chloride, is polymerized in an aqueous medium inside a polymerization vessel, while heat removal is conducted using a reflux condenser. In this process, the liquid level of the contents inside the polymerization vessel is monitored using an electric wave liquid level gauge, which is disposed on the polymerization vessel and radiates microwaves with a frequency of 4 to 20 GHz. The operating efficiency of the reflux condenser can be improved, and the quantity of heat removed by the reflux condenser can be increased. Furthermore, the time required to complete the process, including the raw material addition step and/or the washing step conducted following completion of the polymerization, can be shortened.

Abstract: A process is provided for producing a vinyl chloride-based polymer by polymerization of vinyl chloride or a monomer mixture containing it in a reaction vessel. Heat generated during polymerization is removed using a reflux condenser. When the polymerization rate is within a range from 30% to 50%, a copolymeric polyether, with a weight average molecular weight of 1,500,000 to 2,000,000, and an ethylene oxide to propylene oxide molar ratio within a range from 78/22 to 82/18, is added to the reaction mass. Foaming of the polymer slurry due to the use of the reflux condenser beyond the point where the polymerization rate reaches 60% is suppressed, and the polymer can be produced with no deleterious effects on the quality of the product polymer.

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: Provided is a flame retardant adhesive composition including (A) a halogen-free epoxy resin, (B) a thermoplastic resin and/or a synthetic rubber, (C) a curing agent, (D) a curing accelerator, and (E) a phosphorus-containing filler. Also provided are an adhesive sheet, a coverlay film, and a flexible copper-clad laminate prepared using such a composition. A cured product yielded by curing the composition, as well as the adhesive sheet, the coverlay film, and the flexible copper-clad laminate display excellent flame retardancy and electrical characteristics (anti-migration properties).

Abstract: A process for producing a vinyl chloride-based polymer by suspension polymerization is provided. The polymerization is initiated in the presence of (A) a particular hydroxypropylmethylcellulose, (B) a particular partially saponified PVA with a saponification degree of 75 to 85 mol % and an average polymerization degree of 1000 to 3000, and (C) a particular partially saponified PVA with a saponification degree of 20 to 57 mol % and an average polymerization degree of 150 to 600 in a specified ration, and said (C) is also additionally added to the polymerization system when a conversion rate is 15-50%. Polymers with a high porosity, excellent plasticizer absorption, extremely low levels of fish eyes, and a high bulk specific gravity are produced at a high level of productivity.

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 polymer scale preventive agent for use in the polymerization of a monomer containing an ethylenic double bond is provided. The agent includes (A) a condensation reaction product obtained by reacting an aldehyde compound and a hydroxynaphthalene-based compound in the presence of a reducing agent, and (B) a polymer compound containing a nitrogen atom. This agent is capable of forming a coating with satisfactory scale prevention properties on inner wall surfaces of a polymerization vessel with a single-stage application, enabling the production process time to be shortened and the productivity and quality of polymeric products improved.

Abstract: Provided is a polymer scale deposition-preventive agent. It includes (A) a condensation reaction product of an aldehyde compound and a hydroxynaphthalene compound and (B) a soluble methoxyl group-substituted cellulose ether. The agent is formed into a film having an adequate polymer scale deposition-preventive property in a single-step application. The time for the application process is shortened to improve productivity. Polymer scales can be prevented from adhering to the inner wall surfaces of the polymerization vessel even if a plenty number of batches for polymerization are repeated.

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: A polymer scale preventive agent for use in the polymerization of a monomer containing an ethylenic double bond is provided. The agent includes (A) a condensation reaction product obtained by reacting an aldehyde compound and a hydroxynaphthalene-based compound in the presence of a reducing agent, and (B) a polymer compound containing a nitrogen atom. This agent is capable of forming a coating with satisfactory scale prevention properties on inner wall surfaces of a polymerization vessel with a single-stage application, enabling the production process time to be shortened and the productivity and quality of polymeric products improved.

Abstract: There is provided a process for producing a vinyl chloride-based polymer by conducting a suspension polymerization in an aqueous medium using an oil soluble polymerization initiator, wherein the oil soluble polymerization initiator utilizes a combination of (A) t-amyl peroxyneodecanoate and (B) a peroxide-based polymerization initiator with a 10 hour half-life temperature in a solution with a concentration of 0.1 mol/liter in trichloroethylene within a range of at least 30° C. but less than 55° C., and when a predetermined polymerization conversion rate is reached, the polymerization reaction temperature is raised by a predetermined amount, followed by addition of an antioxidant to said polymerization mixture to halt the polymerization reaction. According to this process, a vinyl chloride-based polymer with good anti-initial discoloration can be produced in high yield and with good productivity.

Abstract: Provided is a polymer scale deposition-preventive agent. It includes (A) a condensation reaction product of an aldehyde compound and a hydroxynaphthalene compound and (B) a soluble methoxyl group-substituted cellulose ether. The agent is formed into a film having an adequate polymer scale deposition-preventive property in a single-step application. The time for the application process is shortened to improve productivity. Polymer scales can be prevented from adhering to the inner wall surfaces of the polymerization vessel even if a plenty number of batches for polymerization are repeated.

Abstract: A production process for a vinyl chloride polymer is proposed in which either vinyl chloride, or a monomer mixture comprising vinyl chloride, is polymerized in an aqueous medium inside a polymerization vessel, while heat removal is conducted using a reflux condenser. In this process, the liquid level of the contents inside the polymerization vessel is monitored using an electric wave liquid level gauge, which is disposed on the polymerization vessel and radiates microwaves with a frequency of 4 to 20 GHz. The operating efficiency of the reflux condenser can be improved, and the quantity of heat removed by the reflux condenser can be increased. Furthermore, the time required to complete the process, including the raw material addition step and/or the washing step conducted following completion of the polymerization, can be shortened.

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: A method of producing a vinyl chloride-based polymer by suspension polymerization is provided, by which heat removal performed by a reflux condenser can be increased, but total heat removal performed by the jacket can be reduced, without affecting the quality of the product polymer. The method includes commencing heat removal when or after a polymerization conversion rate reaches 15%, and controlling said reflux condenser so as to remove a fixed quantity of heat per unit of time depending on the polymerization conversion rate as the polymerization process proceeds.

Abstract: A process is provided for producing a vinyl chloride-based polymer by polymerization of vinyl chloride or a monomer mixture containing it in a reaction vessel. Heat generated during polymerization is removed using a reflux condenser. When the polymerization rate is within a range from 30% to 50%, a copolymeric polyether, with a weight average molecular weight of 1,500,000 to 2,000,000, and an ethylene oxide to propylene oxide molar ratio within a range from 78/22 to 82/18, is added to the reaction mass. Foaming of the polymer slurry due to the use of the reflux condenser beyond the point where the polymerization rate reaches 60% is suppressed, and the polymer can be produced with no deleterious effects on the quality of the product polymer.

Abstract: A process for polymerizing vinyl chloride or a monomer mixture containing vinyl chloride in an aqueous medium in a polymerization vessel fitted with a reflux condenser, characterized by starting to add (A) an anti-foam agent, and (B) a partially saponified polyvinyl alcohol with an average degree of polymerization of 100 to 500 and a saponification degree of 75 to 85 mole %, to a reaction mixture during the operation of said reflux condenser, and continuing the addition of (A) and (B) until recovery of unreacted monomers from said polymerization vessel is completed, thereby preventing the polymer slurry from foaming, rising, or scattering during polymerization or recovery of unreacted monomers.