摘要:
Essentially dry materials are obtained by mechanically dewatering water-moist rubber, prepared by emulsion polymerization and precipitation, to give a compact material having a rubber content of at least 50%, by a process in which the previously dewatered rubber is fed to the feed section of a twin-screw extruder which has screws rotating in the same direction and possesses, in succession in the conveying direction, at least two back-up zones and two associated dewatering orifices, each of which may be provided with a retaining screw, and at least one kneading zone, one devolatilization zone and finally one discharge zone, which may be closed by a die lip, and the water separated off is discharged at the dewatering orifices in liquid form.
摘要:
Toughened thermoplastics are prepared by mechanically dewatering a water-moist elastomer component A containing up to 60% by weight of residual water and mixing the resulting dewatered elastomer component A' with a thermoplastic polymer B in an extruder, by a process in which the elastomer component A is fed to a twin-screw extruder which has corotating, in each case double-flight, screws and essentially includes, in the transport direction,a metering section in which the elastomer component A is fed to the extruder by a metering means,at least one squeeze section which serves for dewatering and contains at least one retarding element and in each case at least one associated dewatering orifice,at least one section provided with a conveying screw or at least one section provided with mixing, kneading or other plasticating elements or combinations of these elements,at least one section in which the thermoplastic polymer B is introduced as a melt into the extruder,at least one section provided with mixing, kneading or other plasticating elements or combinations of these elements,at least one devolatilization section which is provided with at least one devolatilization orifice and in which the residual water is removed as steam, anda discharge zone,the water emerging from the dewatering orifices being present partially or completely in the liquid phase, and the extruder being operated at a screw speed of from 50 to 600 min.sup.-1 and average shear rates of from 20 to 240 s.sup.-1.
摘要:
A process for preparing thermoplastics or polymer blends comprising (A) from 5 to 95% of a water-moist elastomer component containing up to 60% of residual water, (B) from 5 to 95% of a thermoplastic polymer, (C) from 0 to 95% of a further polymer, and (D) from 0 to 70% of additives, said process comprising mixing the components A to D in an extruder with mechanical dewatering of component A, wherein the extruder has at least two rotating screws and, in the conveying direction, is essentially composed of a metering section into which component A is fed, a squeeze section which serves for dewatering component A and contains a retarding element and an associated dewatering orifice which is present upstream of the retarding element by a distance corresponding to at least one screw diameter, a feed section in which the thermoplastic polymer B is introduced as a melt into the extruder, a plastication section with mixing or kneading elements, a devolatilization section with an orifice and in which the remaining water is removed as steam, and a discharge zone.
摘要:
Toughened thermoplastics are prepared by mechanically dewatering a water-moist elastomer component A containing up to 50% by weight of residual water and mixing the resulting dewatered elastomer component A' with a thermoplastic polymer B in a mixing unit, by a process in which the elastomer component A is fed to a twin-screw extruder which has corotating screws and essentially includes, in the transport direction,one unheated metering section in which the elastomer component A is fed to the extruder by a metering means,at least one unheated squeeze section which serves for dewatering and contains at least one retarding element and in each case at least one associated dewatering orifice,at least one section in which the thermoplastic polymer B is introduced as a melt into the extruder,at least one section provided with mixing, kneading or other plasticating elements or combinations of these elements,at least one devolatilization section which is provided with at least one devolatilization orifice and in which the residual water is removed as steam, anda heated discharge zone,and in which the water emerging from the dewatering orifices is present partially or completely in the liquid phase.
摘要:
Toughened thermoplastics are prepared by mixing a water-moist elastomer component A containing up to 60% by weight of residual water with a thermoplastic polymer B and further polymers C and additives D in an extruder with mechanical dewatering of the elastomer component A, by a process in which the components A, B, C and D are fed to a twin-screw extruder which has corotating screws and essentially comprises, in the transport direction, at least one metering section in which the elastomer component A is fed to the extruder by a metering means, at least one squeeze section which serves for dewatering the component A and contains at least one retarding element and in each case at least one associated dewatering orifice, at least one section in which the thermoplastic polymer B is introduced as a melt into the extruder, at least one section provided with mixing, kneading or other plasticating elements or combinations of these elements, at least one devolatilization section which is provided with at least one devolatilization orifice and in which the residual water is removed as steam, and a discharge zone, the water emerging from the dewatering orifices being present partially or completely in the liquid phase, and the components C or D or mixtures thereof, together or separately from one another, being fed to one or more of the stated extruder sections, either together with the component A or B or mixtures thereof or separately from A and B.
摘要:
Toughened thermoplastics are prepared by mechanically dewatering a water-moist elastomer component A containing up to 50% by weight of residual water and mixing the resulting dewatered elastomer component A' with a thermoplastic polymer B in a mixing unit, by a process in which the elastomer component A is fed to a twin-screw extruder which has corotating, in each case triple-flight, screws and essentially includes, in the transport direction, one unheated metering section in which the elastomer component A is fed to the extruder by a metering means, at least one squeeze section which serves for dewatering and contains at least one retarding element and in each case at least one associated dewatering orifice, at least one section in which the thermoplastic polymer B is introduced as a melt into the extruder, at least one section provided with mixing, kneading or other plasticating elements or combinations of these elements, at least one devolatilization section which is provided with at least one devolatilization orifice and in which the residual water is removed as steam, and unheated discharge zone, and in which the water emerging from the dewatering orifices is present partially or completely in the liquid phase.
摘要:
Fluorescent pigments contain essentially a polymer matrix based on polymethyl methacrylate and a nonpolar fluorescent dye from the coumarin or perylene series, the polymer matrix being a crosslinked polymethacrylate or polyacrylate prepared by suspension polymerization.
摘要:
Thermoplastic molding materials contain A) from 50 to 99% by weight, based on the total weight of the molding material, of a toughened polymer, B) from 1 to 20% by weight, based on the total weight of the molding material, of a blend of B.sub.1) a copolymer comprising polymerized units which are derived from a polymerizable carboxylic acid or derivatives thereof and B.sub.2) a polyamide, C) from 0 to 40% by weight of a fibrous or particulate filler or of a mixture thereof and D) from 0 to 20% by weight of conventional additives and processing assistants.
摘要:
Thermoplastic molding materials containA) from 50 to 99% by weight, based on the total weight of the molding material, of a toughened polymer,B) from 1 to 20% by weight, based on the total weight of the molding material, of a blend ofB.sub.1) a copolymer comprising polymerized units which are derived from a polymerizable carboxylic acid or derivatives thereof andB.sub.2) a polyamide,C) from 0 to 40% by weight of a fibrous or particulate filler or of a mixture thereof andD) from 0 to 20% by weight of conventional additives and processing assistants.
摘要:
Solid mixtures of a reactive size and starch, which are obtainable by mixing at least one reactive size with at least one starch in a melt in the presence of at least one destructuring agent for starch under the action of shear forces at from 65 to 250° C. and cooling the melt to room temperature, are used in the form of aqueous dispersions as process assistants in papermaking.