Abstract: A vinyl-based polymer having a mass average molecular weight of 1500 to 10000, which is prepared by a first step of continuously feeding a material mixture containing a vinyl-based monomer to a continuous tank type first reactor, and polymerizing the vinyl-based monomer under the conditions of a polymerization temperature of 150° to 300° C. and a retention time of 1 to 60 minutes at a rate of polymerization of 50 to 99% to obtain a reaction intermediate mixture; and a second step of feeding a polymerization initiator in the amount of 0.01 to 5 parts by mass based on 100 parts by mass of the vinyl-based monomer and the reaction intermediate mixture to a second reactor, and further polymerizing the vinyl-based monomer under the conditions of a polymerization temperature of 100° to 200° C. and a retention time of 10 to 240 minutes at a rate of polymerization of 80% or more.

Abstract: Disclosed is an apparatus for continuous plate formation using belts, in which a polymerizable raw material is fed to one end of a space surrounded by opposed surfaces of two endless belts 1 and 1? facing each other and by gaskets 7 disposed at side edges of these belt surfaces so as to be sandwiched between the surfaces, the polymerizable raw material is polymerized in a section where the belts are heated or cooled with warm water, and a plate-form polymer is taken out of the other end of the space, which contains three or more recovery vessels 13 for recovering the warm water used to heat or cool the belts, and temperature sensing elements (thermometers 14) for measuring the temperature of the warm water recovered in every recovery vessel 13.

Abstract: To be provided are a heat treatment apparatus having blocking members which block gaps between the side walls of nozzle boxes provided with slit nozzles, whose size in the lengthwise direction is greater than the width of a sheet, and the side walls of a heat treatment chamber, and gas having a uniform velocity fluctuating no more than ±25% in the lengthwise direction of the slit nozzles is blown out of the slit nozzles to subject the sheet to heat treatment, resulting in little unevenness of temperature in the widthwise direction and reduced energy loss, and a heat treatment method using this heat treatment apparatus.

Abstract: This invention provides a process for manufacturing a methyl methacrylate polymer comprising the steps of feeding a monomer containing at least 80 wt % of methyl methacrylate and a radical polymerization initiator represented formula (III) to a reactor; polymerizing the material at a polymerization temperature of 110 to 160° C. under the conditions satisfying particular equations between an initiator concentration and a polymerization temperature; feeding a reaction mixture taken out from the reactor to a devolatilization step (feeding step); and separating and removing volatiles from the reaction mixture (devolatilization step).

Abstract: To be provided are a heat treatment apparatus having blocking members which block gaps between the side walls of nozzle boxes provided with slit nozzles, whose size in the lengthwise direction is greater than the width of a sheet, and the side walls of a heat treatment chamber, and gas having a uniform velocity fluctuating no more than ±25% in the lengthwise direction of the slit nozzles is blown out of the slit nozzles to subject the sheet to heat treatment, resulting in little unevenness of temperature in the widthwise direction and reduced energy loss, and a heat treatment method using this heat treatment apparatus.

Abstract: Disclosed are a belt type continuous plate manufacturing apparatus including two endless belts 11, 11? with their facing belt surfaces running toward the same direction at the same speed, and a gasket 7 sandwiched by belt surfaces at their both side edge portions, in which a polymerizable raw material is fed into a space surrounded by the facing belt surfaces and the gasket from its one end, and solidified together with running of the belts in a heating zone, and a plate polymer is taken out from the other end, wherein a plurality of upper and lower roll pairs 4, 4? each composed of an upper roll 4 and a lower roll 4? and having axes orthogonally grossing the belt running direction are placed along the belt running direction as a mechanism of holding the belt surfaces of the endless belts 1, 1? in the heating zone, and the outer diameter D of the roll body portion of the upper and lower roll pair is in the range of 100 mm to 500 mm; and a method of producing a plate polymer using this apparatus.

Abstract: A belt type continuous plate manufacturing apparatus comprising two facing endless belts 1, 1? and gaskets 7 sandwiched by belt surfaces at their both side edge portions, wherein a polymerizable raw material is fed into a space surrounded by the facing belt surfaces and the gaskets 7 from its one end, the polymerizable raw material is solidified together with running of the belts in a heating zone, and the plate polymer is taken out from the other end, characterized in that three or more upper and lower roll pairs satisfying the following formulae (1) and (2) are placed so that respective axes thereof orthogonally cross the belt running direction, between a raw material feeding position and a heating initiation position; and a method of producing a plate polymer by using it: D/Z?0.04 (1), 0.30?D/X?0.99 (2) [D=outermost diameter of roll body portion (mm), Z=width of roll body portion (mm), X=distance between axis centers of adjacent upper and lower roll pairs (mm)].

Abstract: A vinyl-based polymer having a mass average molecular weight of 1500 to 10000, which is prepared by a first step of continuously feeding a material mixture containing a vinyl-based monomer to a continuous tank type first reactor, and polymerizing the vinyl-based monomer under the conditions of a polymerization temperature of 150° to 300° C. and a retention time of 1 to 60 minutes at a rate of polymerization of 50 to 99% to obtain a reaction intermediate mixture; and a second step of feeding a polymerization initiator in the amount of 0.01 to 5 parts by mass based on 100 parts by mass of the vinyl-based monomer and the reaction intermediate mixture to a second reactor, and further polymerizing the vinyl-based monomer under the conditions of a polymerization temperature of 100° to 200° C. and a retention time of 10 to 240 minutes at a rate of polymerization of 80% or more.

Abstract: This invention provides a process for manufacturing a methyl methacrylate polymer comprising the steps of feeding a monomer containing at least 80 wt % of methyl methacrylate and a radical polymerization initiator represented formula (III) to a reactor; polymerizing the material at a polymerization temperature of 110 to 160° C. under the conditions satisfying particular equations between an initiator concentration and a polymerization temperature; feeding a reaction mixture taken out from the reactor to a devolatilization step (feeding step); and separating and removing volatiles from the reaction mixture (devolatilization step). A methyl methacrylate polymer having adequately good optical properties and a plastic optical fiber having improved transmission performance can be prepared according to this invention.

Abstract: This invention provides a process for manufacturing a methyl methacrylate polymer comprising the steps of feeding a monomer containing at least 80 wt % of methyl methacrylate and a radical polymerization initiator represented formula (III) to a reactor; polymerizing the material at a polymerization temperature of 110 to 160° C. under the conditions satisfying particular equations between an initiator concentration and a polymerization temperature; feeding a reaction mixture taken out from the reactor to a devolatilization step (feeding step); and separating and removing volatiles from the reaction mixture (devolatilization step). A methyl methacrylate polymer having adequately good optical properties and a plastic optical fiber having improved transmission performance can be prepared according to this invention.

Abstract: The present invention relates to a process for the production of methacrylic polymers which comprises the steps of, in one perfect mixing type reactor, effecting continuous bulk polymerization at a polymerization temperature of 110 to 160° C.