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:
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:
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.
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 which contain from 0.1 to 10% by weight of a compound of a polyvalent metal are suitable for the production of dull moldings having high impact strength.
摘要:
Pelletized materials based on at least one thermoplastically processable polymer, where the pellets have less than 10% of concave regions and otherwise are convex in every other region, this being determined by means of incident-light interference-contrast spectroscopy, by taking the average value for the ratios of the outline area to the entire outline area for an assembly of pellets.
摘要:
An apparatus intended for extruding thermoplastics and having at least one devolatilization orifice and, if desired, also at least one dewatering orifice, which has been equipped with a metal-wire-mesh composite sheet, with a finely perforated metal sheet, or with a slit diaphragm.
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:
A molding material comprises styrene/butadiene block copolymers obtainable by anionic polymerization and from 0.01 to 1% by weight, based on the polymer, of .alpha.-tocopherol.
摘要:
A particulate polymer A having a mean particle size of less than 1000 nm consists of a1: up to 99.8% by weight of at least one vinylaromatic monomer a1, a2: up to 99.8% by weight of at least one alkyl methacrylate a2 where the alkyl radical is of 1 to 8 carbon atoms, a3: up to 50% by weight of at least one polar, copolymerizable, ethylenically unsaturated monomer a3, a4: from 0.1 to 10% by weight of at least one polyfunctional, crosslinking monomer a4 and a5: from 0.1 to 15, preferably from 0.5 to 10, % by weight of at least one monomer a5 containing one or more acidic, basic or epoxy groups, the sum of the components a1, a2 and a3 being from 75 to 99.8% by weight, based on A, and the sum of a1, a2, a3, a4 and a5 being 100% by weight, based on A.