Abstract: A method of producing polycarbonate resin pellets containing very less residual organic solvent and low molecular weight volatile matters and having a high transparency by melt-kneading a polycarbonate resin powder in an extruder equipped with a screw having a material seal mechanism, and vents, and devolatilizing the residual organic solvent and/or the low molecular weight volatile matters at the vent portion and then extruding the molten resin.The polycarbonate resin pellets are suitable for optical grade articles and automobile lenses.

Abstract: A grafted aromatic polycarbonate resin is produced by melt-kneading a graft precursor comprising a mixture of 35 to 95% by weight of aromatic polycarbonate resin particles and 65 to 5% by weight of vinylic copolymer containing active oxygen, the vinylic copolymer being present in the aromatic polycarbonate resin particles, thereby subjecting to grafting reaction of the aromatic polycarbonate resin and the vinylic copolymer, where the grafting reaction can be sufficiently carried out and thus the grafted polycarbonate resin is useful for molding materials for optical disks, optical lenses, etc. a polymer blend-compatible agent, adhesives, paints, etc.

Abstract: A polycarbonate resin solution for forming a thermal-sublimating dye-receiving layer film, comprising a random copolycarbonate resin dissolved in an organic solvent, the resin having a structural unit represented by following formula (1) and a structural formula represented by following formula (2) or (3), the molar ratio of the structural unit represented by formula (1) to the structural unit represented by formula (2) or (3) being from 35/65 to 65/35, and having a number average molecular weight of from 5,000 to 50,000. ##STR1## wherein R.sup.1 to R.sup.12 each represents a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms and in formula (1), A represents a straight chain, branched, or cyclic alkylidene group having from 1 to 10 carbon atoms, an aryl-substituted alkylidene group, an arylene group, or a sulfonyl group.

Abstract: Disclosed is a process for producing a grafted polycarbonate resin for optical use, which comprises adding to an aqueous suspension of an aromatic polycarbonate resin having radical-polymerizable unsaturated terminal group on a molecule wherein the aromatic polycarbonate resin has an average particle diameter of 0.1 to 5 mm and an apparent density of 0.2 to 0.9 g/cm.sup.3, a vinyl monomer and a radical-polymerization initiator, heating the aqueous suspension at a lower temperature by 5.degree. C. to 20.degree. C. than the decomposition temperature for a half-life period of 10 hours of the radical-polymerization initiator, thereby impregnating the polycarbonate resin with the vinyl monomer and the radical-polymerization initiator, then elevating the temperature to the range of from a lower temperature by 50.degree. C. to a higher temperature by 30.degree. C.

Abstract: In a process for producing a halogenated polycarbonate molded article from a powder or pellets of a halogenated polycarbonate resin or composition thereof by means of injection molding using an injection molding machine, the improvement wherein the injection molding machine comprises a cylinder whose inner circumferential wall being made of a corrosion-resistant and abrasion-resistant alloy comprising alloy component (1), (2), or (3) given below, and a screw part made of a steel having a metal coating formed by hard chromium plating or hard nickel plating or made of SUS420, SUS440, Hastelloy C, or a steel comprising alloy component (4) given below:______________________________________ Alloy component (1): C: 0.5-2 wt % Si: 1-5 wt % B: 0.5-5 wt % Ni: 10-25 wt % Cr: 20-35 wt % W: 10-25 wt % Cu: 0.5 -5 wt % Remainder: Co and unavoidable impurities, Alloy component (2): Si: 0.2-4 wt % Mn: 0.

Abstract: A method of coloring a polycarbonate extruded or molded product for optical members, which is colored by a liquid coloring process for obtaining a colored polycarbonate extruded or molded product for optical members by extrusion or injection molding. The process involves mixing a polycarbonate resin for optical members and a liquid coloring agent dispersion obtained by dispersing a coloring agent in a dispersing agent. The dispersing agent includes a specific saturated fatty acid ester or silicon oil. After mixing the polycarbonate resin and liquid coloring agent dispersion, the resulting mixture is melted and thereafter extruded or molded to form a product for optical members.

Abstract: A process for producing a low-particle-content transparent thermoplastic resin solution, which comprises centrifuging a solution of a transparent thermoplastic resin containing free water to separate it into a resin solution phase, an aqueous phase and an intermediate layer, and separating the resin solution phase from the aqueous phase and the intermediate layer. By this process, the number of particles having a size of at least 0.5 .mu.m in the resin solution can be decreased to 10,000 or less, preferably substantially zero, per gram of the transparent thermoplastic resin.

Abstract: A process for producing a polycarbonate molded article having a low dust level from a polycarbonate resin in the form of a powder or pellets by injection molding using an injection molding machine. The injection molding machine includes a cylinder whose inner circumferential wall is made of a corrosion- and abrasion-resistant alloy from alloy components (1), (2), or (3) given below and a screw part made of a steel having a metal coating formed of hard chromium plating or hard nickel plating or formed of titanium carbide or tungsten carbide, or is made of SUS420, SUS440, Hastelloy C, or a steel of alloy component (4) given below:Alloy components (1):C: 0.5-1.5 wt%Si: 1.0-2.0 wt%B: 0.5-2.5 wt%Ni: 10.0-20.0 wt%Cr: 20.0-30.0 wt%W: 10.0-20.0 wt%Cu: 0.5-2.0 wt%Remainder: Co and unavoidable impurities,Alloy components (2):Ni: 0.0-2.0 wt%Cr: 5.0-15.0 wt%Fe: 0.0-1.0 wt%Mn: 0.1-2.0 wt%Si: 0.2-4.0 wt%B: 2.0-4.0 wt%Remainder: Co and unavoidable impurities,Alloy components (3):Cr: 5.0-10.0 wt%Co: 5.0-40.0 wt%Fe: 0.0-10.

Abstract: A method for producing a purified polycarbonate resin is disclosed, comprising contacting a solid polycarbonate resin with a fluid comprising at least 70% by weight of carbon dioxide and having a temperature of 30.degree. to 120.degree. C. and a pressure of at least 10 kg/cm.sup.2. The method can effectively remove almost all the impurities contained in the polycarbonate resin within a very short period of time, thereby providing highly purified polycarbonate resin materials which are suitably used in the fields of information, electronic and medical industries.

Abstract: A process for producing a low-particle polycarbonate resin molding material suitable for use as molding material for optical materials is disclosed, which comprises directly supplying a polycarbonate resin wet powder having a water content of from 0.5 to 10.0% by weight and an organic solvent content of from 0.01 to 5.0% by weight, said wet powder, when dried, having a weight average particle diameter of from 5 to 60 mesh, to a vented extruder and extruding the wet powder while venting to obtain pellets containing not more than 20 ppm of a residual halogenated hydrocarbon. The molding material has a greatly decreased solvent content while being freed from a particle content increase.

Abstract: A process for producing an oxymethylene copolymer by copolymerizing trioxane with at least one cyclic comonomer selected from the group consisting of cyclic ethers and cyclic formals, said process comprising(1) polymerizing trioxane alone or with a cyclic comonomer in the presence of a polymerization catalyst until the conversion of trioxane reaches 10 to 95%, and(2) thereafter adding a cyclic comonomer and a polymerization catalyst to the reaction system and continuing the polymerization.

Abstract: An acetal resin composition comprising an acetal resin and a low molecular weight polycarbonate compound having an intrinsic viscosity of 0.2 dl/g or less in methylene chloride at 25.degree. C. and, optionally, an organic or inorganic filler is disclosed. Said composition has improved surface gloss and weather resistance.

Abstract: An acetal resin composition comprising(A) an acetal resin,(B) at least one member selected from the group consisting of (1) a polyfunctional cyanic acid ester or its prepolymer, (2) a mixture of a polyfunctional cyanic acid ester or its prepolymer with a polyfunctional maleimide or its prepolymer and (3) a pre-copolymer of a polyfunctional cyanic acid ester and a polyfunctional maleimide,(C) an amine-substituted triazine and/or a cyanoguanidine compound, and(D) an inorganic filler other than glass, and/or an organic filler.

Abstract: In a process for producing a stabilized oxymethylene copolymer by heat-melting, at a temperature ranging between the melting point of the copolymer and a temperature 100.degree. C.

Abstract: A process for producing a polyacetal homopolymer or copolymer which comprises continuously feeding a liquid starting mixture containing molten trioxane and a catalyst and optionally a comonomer through a feed opening of a reactor, said reactor being a continuously stirring-type mixer having two stirring shafts having a plurality of plate-like paddles fixed thereto the cross-section of each of said paddles taken perpendicularly of the axial direction of the stirring shaft having a shape of a convex lens, an ellipse or a quasipolygon inscribing a phantom circle at each vertex, one of said paddles facing another paddle fixed to the other stirring shaft and said one paddle being positioned such that it rotates while the edges thereof keep a slight clearance from the inner surface of the barrel and the other paddle; polymerizing the starting mixture while moving it toward the discharge opening by the rotation of the paddles, the improvement wherein the profiles of the paddles are changed, or the arrangement of the

Abstract: In a process for producing an oxymethylene homopolymer or copolymer having improved stability which comprises polymerizing trioxane or a mixture of trioxane and a cyclic ether and/or a cyclic acetal in bulk in the presence of a catalyst which is at least one compound selected from the group consisting of boron trifluoride, boron trifluoride hydrate and coordination compounds of boron trifluoride with organic compounds containing an oxygen or sulfur atom, the improvement which comprises performing the bulk polymerization without destroying the bulk polymerization system, or which comprises adding a tertiary phosphine compound to the polymerization system to deactivate the catalyst, before the polymerization system formed by the bulk polymerization is destroyed.

Abstract: In a process for producing a stabilized oxymethylene copolymer which comprises heat-melting an oxymethylene copolymer having unstable, unblocked terminals obtained by the copolymerization of trioxane with a cyclic acetal and/or a cyclic ether to heat decompose it in the presence of available heat stabilizers; the improvement which comprises heating said oxymethylene copolymer having unblocked terminals in a mixer at a temperature between the melting point of said oxymethylene copolymer and a point 100.degree. C. higher than said melting point under a pressure of 0.

Abstract: A process for polymerizing trioxane made from an aqueous solution of methanol-containing formaldehyde by a conventional method or copolymerizing the trioxane with another monomer, characterized bycooling the trioxane to crystallize it,allowing the trioxane in a crystalline state to stand in an open system in an atmosphere of air or an inert gas to remove polyoxymethylene dimethoxide from the trioxane,melting the trioxane, andpolymerizing the trioxane or copolymerizing the trioxane and the another monomer.

Abstract: A process for continuously producing an oxymethylene polymer by continuously polymerizing a starting monomer containing at least 50 mole% of trioxane in bulk in the presence of a catalyst, which comprises feeding the starting monomer into a first-stage polymerization reactor having a self-cleaning action to perform a first-stage polymerization reaction until the conversion reaches 40 to 70%, withdrawing the reaction mixture as a powder from the outlet of the first-stage polymerization reactor, feeding the reaction mixture into a second-stage polymerization reactor having a stirring action to perform a second-stage polymerization reaction until the conversion reaches 95 to 100%, and then withdrawing the polymerization product as a powder from the outlet of the second-stage polymerization reactor.

Abstract: A process for preparing oxymethylene polymers which comprises polymerizing trioxane or both trioxane and a specific cyclic ether in the presence of a catalytic amount of a boron fluoride-type catalyst, stopping the polymerization, and then subjecting the resulting polymer to a terminal stabilizing treatment, wherein the polymerization is stopped by adding a specific trivalent organic phosphorus compound and then the terminal stabilizing treatment is performed without removing the catalyst from the polymer.