Abstract:
Production of impact-resistant styrene copolymers by polymerizing styrene and acrylonitrile in the presence of butadiene polymers, the bulk of the acrylonitrile being added to the system after a disperse phase has formed from the homogeneous rubber monomers.
Abstract:
PROCESS FOR THE PRODUCTION OF IMPACT-RESISTANT POLYMERS BY THE CONTINUOUS POLYMERIZATION OF A SOLUTION OF A DIENE ELASTOMER OR ELASTOMERIC COPOLYMER OF ETHYLENE AND PROPYLENE, THE STARTING MATERIALS BEING FIRST PARTIALLY POLYMERIZED TO SUCH AN EXTENT THAT THE SOLIDS CONTENT OF THE MIXTURE IS 1.1 TO 2 TIMES THE CONTENT OF DIENE ELASTOMER BUT NOT MORE THAN 16% BY WEIGHT, THEN INTRODUCED INTO AN ISOTHERMAL POLYMERIZATION STAGE WHERE A MIXTURE CONTAINING LESS THAN 50% BY WEIGHT OF SOLIDS IS PREPARED AT A TEMPERATURE OF FROM 50* TO 150*C. WHILE MIXING, WHICH MIXTURE IS TOTALLY POLYMERIZED IN THE DOWNSTREAM CONTINUOUS POLYMERIZATION STAGES AT A TEMPERATURE OF UP TO 250*C. TO GIVE A MIXTURE CONTAINING MORE THAN 60% BY WEIGHT OF SOLIDS, AND THEN FREED IN A CONVENTIONAL MANNER FROM VOLATILE CONSTITUENTS.
Abstract:
PROBLEM TO BE SOLVED: To produce an impact-resistant thermoplastic resin composed of a wet elastomer component and a fragile thermoplastic polymer in an industrially simple manner by one treatment process if possible. SOLUTION: An elastomer component A is supplied to a twin-screw extruder formed from a distribution section, a crushing section, a, section supplying a thermoplastic polymer B to the extruder, a section equipped with a mixing element, a kneading element and/or a separate plasticizing element, a degassing section and a feed-out zone in a feed direction and equipped with screws rotated in the same way and the water discharged from a dehydration opening is allowed to be present as a liquid phase partially or wholly. Therefore, the residual water contained in rubber partially dehydrated at first is already removed as water in the first crushing section and the feed amt. of rubber is 3-8wt.% of the amt. of the wet rubber in the first crushing section and below 1wt.% in a second crushing section.
Abstract:
PROBLEM TO BE SOLVED: To manufacture impact resistant thermoplastic in a single step as far as possible by supplying elastomer composition containing residual moisture up to specific wt.% to a biaxial extruder having double threaded screws rotating in the same direction so that the moisture from a dehydration part partly or entirely becomes a liquid state. SOLUTION: The zones of a biaxial extruder are arranged as follows toward the axial direction of the extruder. The zones include the metering supply zone 2 of elastomer composition A containing the residual moisture up to 60wt.%, first compression zone 3, second compression zone 3', intermediate site feeding screw zone 0, zone 4 supplied with melted material of thermoplastic B, first plasticizing zone 5, second plasticizing zone 5', first deaerating zone 6, second deaerating zone 6' and discharge zone 7. The two screws of the extruder are formed as deeply engraved threads and double threads. The extruder is operated by the number of revolutions of the screw from 50 to 600min , and shearing speed of 20 to 240s .
Abstract:
The invention concerns a method of producing multi-layer medicaments in solid form for oral or rectal administration. At least two substances, which each comprise a thermoplastic, pharmacologically acceptable polymer binder which is soluble or can swell in a physiological environment, at least one of the substances comprising a pharmaceutical active substance, are coextruded and the coextruded multi-layer material is shaped to form the desired medicament.
Abstract:
The invention relates to a method for producing solid forms of administration by means of melt extrusion. A polymer binder, at least one pharmaceutical active agent and optionally, other additives are mixed and the mixture is melted in an extruder and then extruded in the form of a continuous plastic product strand. The inventive method is characterised in that the extruder used is a planetary roller extruder (10) which preferably has one central spindle (13) and six planetary spindles (14).
Abstract:
The invention relates to a tube bundle heat exchanger (R) for removing dissolved substances from a polymer solution (P) by degassing, having a bundle of tubes (R) which are arranged parallel to one another and vertically and are fastened at both ends in each case in one tube plate (B), and having a degassing region below the lower tube plate (B), having an insert (1) in each tube (R), which insert (1) narrows the free throughflow cross section through the tube (R), and wherein the polymer solution (P) is supplied into the tubes (R) in a single-phase liquid state, and having a casing space around the tubes (R) which is traversed by a heat carrier, wherein the degassing takes place by means of a pressure drop between the inlet pressure of the polymer solution (P) in the tube bundle heat exchanger (R) and the degassing region, characterized in that each insert (1) is designed in such a way as to generate a pressure step between the inlet pressure and the pressure in the degassing region, by means of which pressure step a predefined low residual content of dissolved substances is obtained in the degassed polymer, and an additional heat input which is necessary for this purpose takes place via the heat carrier into the single-phase liquid polymer solution (P).
Abstract:
The present invention relates to a mixing apparatus at least composed of a screw-based machine S 1 and a screw-based machine S 2 , where S 1 has heating equipment, at least in the plasticizing and homogenizing zone, and where the outlet from S 2 has been connected to the screw-containing barrel of S 1 , within the plasticizing or homogenizing zone of S 1 , a substantive feature of which is that the connection between S 1 and S 2 is brought about by a connector which has cooling equipment effective as far as the inner wall of the screw-containing barrel of S 1 , and to a process for preparing thermoplastically processable molding compositions, in particular additive masterbatches, from at least one thermoplastic component C 1 and at least one component C 2 , where the melting point or decomposition temperature T M C2 of C 2 is lower, by at least about 50° C., than the temperature T H C1 , which is the lower limit of the thermoforming range of C 1 , and where most of C 2 is melted only after contact with C 1.
Abstract:
A process for producing thin absorbent planar structures which may be used in hygiene products such as diapers, incontinence products, wound contact materials or sanitary napkins to absorb body fluids, comprises the steps of: A) producing a mixture of an adhesive in dispersion form and a particulate absorbent by fluidizing the components, B) applying the mixture of adhesive and absorbent uniformly to the surface of one side of a first planar backing material, C) one side of a second planar backing material is applied to the mixture of adhesive and absorbent that is present on the surface of one side of the first planar backing material, so producing a sandwichlike intermediate, and D) the sandwichlike intermediate is processed to the end product at a temperature of at least 90° C., a pressure of from 4 to 50 bar, and a pressing time of from 0.5 to 5 min.