Abstract: The disclosure is directed to fiber blends of melamine resin fibers and aramid fibers.

Abstract: A process for producing fibers by spinning a resin by a centrifugal spinning process comprises supplying a resin solution having a viscosity from 50 to 200 Pa.s at the spinning temperature to a whirler plate and ensuring that the resin solution is under a sufficient pressure to completely fill the nozzles of the whirler plate as the fibers are being spun. The process is particularly suitable for producing fibers based on amino resins. In the apparatus the supply line for the resin is preferably located within the driveshaft.

Abstract: A thermally stable electrical insulating material comprises melamine resin fibers and a polymer fibril binder with or without a synthetic resin powder and mineral fillers.

Abstract: A condensation polymer, obtainable by condensation of a mixture containing, as chief components,(A) from 90 to 99.9% molar of a mixture substantially consisting of(a) from 30 to 99% molar of melamine and(b) from 1 to 70% molar of a substituted melamine of the general formula I ##STR1## in which X, X', and X" are selected from the group consisting of --NH.sub.2, --NHR, and --NRR', and only one or two of X, X', and X" denote(s) --NH.sub.2, and R and R' are selected from the group consisting of hydroxy-C.sub.2 -C.sub.10 -alkyl, hydroxy-C.sub.2 -C.sub.4 -alkyl-(oxa-C.sub.2 -C.sub.4 -alkyl).sub.n, where n is an integer from 1 to 5, and amino-C.sub.2 -C.sub.12 -alkyl, or mixtures of melamines I, and(B) from 0.1 to 10% molar, based on (A) and (B), of unsubstituted phenols or phenols substituted by radicals selected from the group consisting of C.sub.1 -C.sub.9 -alkyl and hydroxy, or of C.sub.1 -C.sub.

Abstract: A process for the preparation of expandable granules based on polyaryl ether sulfones and/or polyether imides, containing from 5 to 20% by weight of a physical blowing agent, the blowing agent and the polymers being mixed in an extruder and subsequently extruded directly into a medium at less than 40.degree. C., and a process for the production of foams from expandable granules based on polyaryl ether sulfones and/or polyether imides, containing from 5 to 20% by weight of a physical blowing agent, the granules being press molded at from 120.degree. to 250.degree. C. and at a pressure of from 5 to 30 bar to form a sheet, and the sheet being subsequently foamed by reducing the pressure, are described.

Abstract: Foams having high compressive strength are obtained by extrusion of a mixture of a styrene polymer and from 3 to 9% by weight of a blowing agent consisting of from 80 to 100% by weight of CO.sub.2 and from 0 to 20% by weight of one or more halohydrocarbons or hydrocarbons which are gaseous at room temperature, the mixture being extruded into a zone under from 0.1 to 2 bar gage pressure and the foam being allowed to stabilize under this pressure.

Abstract: The continuous preparation of melamine/formaldehyde precondensate solutions is carried out by a process in which melamine, formaldehyde and, if required, modifiers and/or additives are metered into a continuous mixer, and the homogeneous mixture is passed into a single-screw or twin-screw extruder, condensed at elevated temperatures, cooled and extruded.

Abstract: Polyolefin foams which have a density of from 30 to 300 g/l, do not exhibit after-shrinkage and possess taut cells are prepared by letting down a polyolefin/blowing agent gel, the latter first being let down to 0.1-10 bar gage pressure and the foam being kept at this pressure until it has cooled to at least 20.degree. C. below the expansion temperature.

Abstract: In order to compound organic materials which are crystalline under standard conditions, these materials, in the pulverulent and/or molten state, are processed in a self-purging, twin-screw extruder in which the screws rotate in the same direction, ejected through one or more narrow passages into a low pressure zone, cooled and comminuted to give particles. In order to improve the pourability and shelf life, the materials are completely crystallized by the time they reach the end of the screws, and are heated during discharge through the narrow passage, in order to form a melt film. Dust-free granules havig a smooth surface can be produced in this manner.

Abstract: In order to prepare thermoplastic polyurethane elastomers(a) organic diisocyanate,(b) polyhydroxyl compounds with molecular weights of 500 to 8,000, and(c) chain extenders with molecular weights of 60 to 400 in the presence of(d) catalysts, and optionally(e) auxiliaries, and/or(f) additivesare reacted in two reaction stages at temperatures from 60.degree. C. to 250.degree. C. In the first reaction stage the components are continuously mixed, the reaction mixture is applied to a carrier, preferably a conveyor band of thermoplastic material, and is allowed to react at the reaction temperature until solidified. Subsequently, the solidified reaction mixture is melted in an extruder and the reaction is completed in the second reaction stage.

Abstract: A sheet-like packing material consisting ofA. from 2 to 90% by weight of melamine resin or phenol resin fibers and/or fibrids,B. from 5 to 90% by weight of finely divided inorganic fillers, preferably cement, andC. from 2 to 40% by weight of organic binders, preferably rubber, with or withoutD. from 0.1 to 50% by weight of thermoplastic fibrids, the percentages summing to 100,possesses low gas permeability, high compressive creep strength and advantageous compressibility, resilience and swelling behavior.

Abstract: A mixing head for multicomponent plastics, especially polyurethane, in whose mixing chamber (2) a hollow piston (7) can be moved to and fro to control the component streams. The hollow piston contains an expulsion piston (8), which is movable independently of the hollow piston, and which can be passed through an outlet tube (3) which adjoins the outlet orifice (4). The end face (12) of the hollow piston forms, together with the mixing chamber wall (11) nearest the sprue, a shearing gap in which the components are mixed. As a result of the design and arrangement of the pistons (7) and (8), good mixing is achievable even under critical conditions, and the mixing chamber is also easily cleaned.

Abstract: Manufacture of fibrids from polymers or copolymers containing fluorine in a fluid precipitation medium under the action of shearing forces.