摘要:
Graft copolymers (P1) contain, in any desired sequence, at least (P1.1) a hard segment having a glass transition temperature of at least 11.degree. C., which contains at least one vinylaromatic monomer as the monomer or as one of two or more monomers copolymerizable with one another and a crosslinker component comprising at least dihydrodicyclopentadienyl acrylate as a crosslinking agent having two or more functional groups of different reactivity and at least one crosslinking agent having two or more functional groups of the same reactivity, and (P1.2) a soft segment having a glass transition temperature of not more than 10.degree. C., which contains at least one acrylate as the monomer or as one of two or more monomers copolymerizable with one another, and blends and thermoplastic materials contain said graft copolymers.
摘要:
A thermoplastic molding composition having little intrinsic color is produced from a graft copolymer and a thermoplastic polymer. The graft copolymer is produced from a soft elastomeric particulate graft base obtained by polymerization of a conjugated diene alone or with a small amount of a monoethylenically unsaturated monomer, upon which is grafted a vinylaromatic monomer and acrylonitrile and optionally another monoethylenically unsaturated monomer. The thermoplastic polymer is a copolymer of a vinylaromatic monomer and acrylonitrile and optionally an additional monoethylenically unsaturated monomer. The thermoplastic molding composition has a low level of intrinsic color coupled with good mechanical properties and can be processed by, for example, extrusion, injection molding, calendaring, blow molding, compression molding, or sintering.
摘要:
Solid preparations are obtainable by melt extrusion ofA) at least one active compound,B) a mixture ofB1) from 10 to 90% by weight of a water-soluble, thermoplastic polymer, andB2) from 10 to 90% by weight of a low-substituted hydroxypropylcellulose, andC) from 0 to 50% by weight, based on the total amount of the preparation, of customary pharmaceutical auxiliaries.
摘要:
A fluidized-bed process for preparing hydrogen peroxide, C.sub.1 -C.sub.4 -monopercarboxylic acids and C.sub.4 -C.sub.18 -dipercarboxylic acid complexes in which a solution of hydrogen peroxide, a C.sub.1 -C.sub.4 -monopercarboxylic acid, a C.sub.4 -C.sub.18 -dipercarboxylic acid or a mixture thereof in water or carboxylic acids is applied to a pulverulent or pregranulated matrix and fluidized-bed drying takes place.
摘要:
A process for coating drug forms by application of an aqueous dispersion which contains as binder a redispersed latex of an emulsion polymer onto the drug form and evaporating the water at a temperature at which the latex particles form a film, comprises employing a polymer dispersion which has been prepared by emulsion polymerization of one part by weight of at least one ethylenically unsaturated polymerizable monomer, by means of initiators which provide free radicals, in the presence of from 0.1 to 2 parts by weight of saccharified starch, and from 0 to 5% by weight, based on the monomer or monomers, of a surfactant, with or without further conventional additives, drying to a powder and redispersing in water.
摘要:
Shear forces are used for essentially salt-free coagulation of plastics dispersions or rubber dispersions. For this, method of use is made of an apparatus with at least one shearing module which has a stator and a rotor arranged within the stator, where the surfaces facing toward one another in the stator and in the rotor are in each case smooth, or at least the rotor exhibits a structure formed on its surface and facing from this in the direction of the stator, and between the stator and the rotor there is a gap of predetermined gap width. The process is carried out by passing the dispersion to be coagulated through the gap between stator and rotor and precipitating the dispersion by rotation of the rotor with predetermined shear rate and shear deformation.
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:
A process for preparing a free-flowing redispersible powder composed of a vinyl-pyrrolidone/vinyl acetate copolymer containing 15-40% by weight of vinylpyrrolidone units wherein the mixture of the monomers is copolymerized in organic solution, the resulting solution is, after addition of a surfactant, subjected to replacement of the solvent by water, and the resulting dispersion is spray- or freeze-dried, and the use of the redispersible powder for producing paints and coating compositions, glues and adhesives and, in particular, the matrix and/or coating of solid slow-release pharma-ceutical forms and of hair-spray formulations are described.
摘要:
Slow-release matrix pellets with a spherical or lenticular shape and uniform maximum diameters in the range from 0.5 to 4 mm, composed of a) 0.1-87% by weight of at least one biologically active compound, b) 5-50% by weight of at least one water-insoluble polymer, c) 5-45% by weight of at least one lipophilic component as plasticizer for polymer b), d) 3-40% by weight of a natural or semisynthetic gel former, e) 0-50% by weight of one or more conventional formulation aids.