Abstract: An actuator is operatively connected to a closing member via a tappet. The closing member is introduced in a valve chamber and forms, with a conically tapering valve seat as part of a servovalve, a seal resistant to high pressure. The cross section of the closing member is configured to be mushroom-shaped, a closing head being in the form of a part-sphere and having a central flattening, with the result that the tappet has an enlarged bearing surface. A stem of the closing member is surrounded by a valve spring. The closing member is preferably shaped out of a solid sphere.

Abstract: A thermoplastic polyurethane elastomer is disclosed obtained by reactingA) diisocyanates,B) polyhydroxy compounds and/or polyamines, withC) as chain extenders mixtures ofC1) benzene substituted with at least two hydroxyalkyl, hydroxyalkoxy, aminoalkyl and/or aminoalkoxy groups andC2) an alkanediol with 4 to 44 C atoms. The reaction is further characterized in that the molar ratio C1 to C2=60 to 40 to 95 to 5 and in that the equivalent ratio of NCO groups to the sum of the NCO-reactive groups is about 0.9 to 1.20.

Abstract: The present invention is directed to a process for the production of moldings from plastic forming materials in metal molds comprising coating at least a portion of the internal walls of the mold with an external mold release agent, introducing the plastic forming material into the mold, closing the mold, and removing the product from the mold, the improvement wherein the external mold release agent comprises one or more organic compounds the molecules of contain on a statistical averageA) from 0.5 to 1.2 polar groups selected from the group consisting of --CN, --NC, --NCO, --CNO, --OCN, --SCN and --NCS andB) at least one non-polar hydrocarbon chain with at least 12 carbon atoms, which chain may be at least partially fluorinated, and which may be interrupted by heteroatoms and/or carbonyl groups.

Abstract: When pulverising polyurethane, polyurea and/or polyurethane/polyurea materials in a roller mill with at least two rollers (2,3) rotating at different circumferential speeds, a very economical method of operation is achieved by returning the coarse fraction falling freely out of the roll slit (4) to the roll slit (4) and stripping the fine material adhering to the roller (3) with the higher circumferential speed and discharging it separately from the coarse fraction.

Abstract: The invention relates to a process for the preparation of single-layered or multilayered molded articles from particles of polyisocyanate-polyaddition products by shaping a specified mixtures under heat and pressure. The mixture contains quasi-thermoplastic particles of polyisocyanate-polyaddition products and one or more processing aids.

Abstract: Composite structures are produced by placing at least two flat, thermoplastically formable plastic materials one above the other and thermoplasticially molding the materials under sufficient conditions of temperature and pressure that molding is accompanied by intimate union of individual layers of the structure. At least one of the plastic materials is based on a polyisocyanate polyaddition product having a density of at least 0.8 g/cm.sup.3 and is prepared by reacting:a) an aromatic polyisocyanate,b) a compound having a molecular weight of about 1800 to 12,000 and containing an average of at least 2.5 isocyanate reactive groups,c) optionally a diamine having a molecular weight of from 108 to 400 and containing two primary and/or secondary aromatically bound amino groups, andd) optionally an aliphatic or cycloaliphatic polyol and/or an aliphatic or cycloaliphatic polyamine having a molecular weight of from 60 to 1799 and which may contain ether groups,at an isocyanate index of from about 60 to 140.

Abstract: The present invention is directed to a process of thermoplastically molding a specific foam composition. The composition is formed by reacting an isocyanate and a relatively low molecular weight tri or higher polyol in the presence of a blowing agent.

Abstract: The invention is directed to a process for the production of molded articles by deep-drawing a prefabricated polyurethane(urea) part produced from a polyisocyanate polyaddition product having a specific gravity of at least 0.8 g/cm.sup.3. The part is placed inside a deep-drawing mold and pressed at a temperature of up to 230.degree. C. and a pressure of up to 1,000 bar. After the deep-drawing process, the part is subjected to a dwell time of at least 10 seconds at a temperature of up to 230.degree. C. and a pressure of up to 1,000 and is immediately thereafter removed from the mold.

Abstract: The present invention relates to a process for the preparation of moldings or films based on polyisocyanate polyadducts comprising thermoplastically molding, at a temperature of at least 50.degree. C. and at a pressure of at least 5 bar, polyisocyanate polyadducts obtained by reacting in closed molds using the reaction injection molding technique aromatic polyisocyanates; compounds having a molecular weight of from 1800 to 12,000 and containing on a statistical average at least 2.5 isocyanate-reactive groups; and one or more components selected from a diamine containing two primary and/or secondary aromatically bound amino groups and and an aliphatic or cycloaliphatic polyol or polyamine; with the provisos that the quantity of isocyanate-reactive compound is at least 30% by weight based on the total quantity of the components and that at least one of the diamine, polyol, or polyamine components comprises at least 5% by weight based on the weight of the isocyanate-reactive compound.

Abstract: The present invention is directed to composite structures by thermoplastically shaping an assembly of at least two flat thermoplastically formable plastic materials placed in layers one above the other and optionally at least one upper, lower and/or intermediate layer containing a reinforcing or filler material under such conditions of temperature and pressure that shaping is accompanied by intimate union of the individual layers of the assembly, characterized in that at least one of the flat plastic materials is based on a polyisocyanate polyaddition product having a density of at least 0.8 g/cm.sup.3 which has been prepared by the reaction of(a) aromatic polyisocyanates,(b) compounds having a molecular weight of 1800 to about 12000 and containing a statistical average of at least 2.

Abstract: The present invention relates to thermoplastic mixtures of 90 to 20% by weight of an aromatic polycarbonate with an Mw of 15,000 to 25,000 and p-(iso-C.sub.8 -C.sub.9 -alkyl)-phenyl end groups and 10 to 80% by weight of a polystyrene with an Mw of 80,000 to 400,000, and to their use as substrates for optical data memories.

Abstract: A turbosupercharging system is provided having two turbosuperchargers of the same type and dimensions, connected in parallel. A cut-in valve is installed in an exhaust manifold in which the second turbine is installed. When the valve is closed, the entire exhaust blast coming from the engine is directed to the first turbine. In this manner, even at low engine speeds, the first turbine can deliver an effective amount of power to its compressor, thereby introducing a detectable supercharge into the cylinders of the internal combustion engine. This supercharge also holds a biased nonreturn valve which is built into the manifold pressure line of the second tubosupercharger is a closed position. When the cut-in valve is completely open the exhaust blast is divided between both turbines, thereby allowing a pressure build up in the manifold pressure line of the second turbosupercharger.

Abstract: In apparatuses for the preparation of phthalic anhydride and/or maleic anhydride by catalytic oxidation of naphthalene or o-xylene with air, reduced pressure is generated using liquid-jet pumps, and wash liquid is removed from the exit gas washer as a pump fluid for the liquid-jet pumps and is subsequently recycled to the exit gas washer.

Abstract: Desublimator for isolating sublimation products from reaction gases, which consists of a closed housing and a plurality of rows of finned tubes accommodated horizontally and superposedly therein, successive superposed finned tubes being supported, and mutually spaced, with limited adjustability, by means of cage-like perforated sliding shoes surrounding them in a box-like manner, the sliding shoes of the individual finned tubes being directly stacked one above the other and resting loosely on common supporting girders anchored to the housing, and the supporting girders having, in cross-section, the outline of a triangle with its apex pointing downward.

Abstract: Process for the recovery of phthalic anhydride in which gases as obtained in the catalytic atmospheric oxidation of o-xylene or naphthalene are treated with a hydrocarbon containing C.sub.26.sub.- paraffins, cooling, if necessary, the hydrocarbon laden with phthalic anhydride, separating the solid phthalic anhydride followed by melting and distillation thereof.

Abstract: A finned tube heat exchanger for isolating sublimates, especially phthalic anhydride, in which the finned tubes arranged in parallel alongside one another and above one another and connected by headers and tube bends permit flow through them successively in the first, then the third, then the second and then the fourth row, and that the transverse fins are arranged in rows staggered laterally in opposite directions by an amount corresponding to from half the spacing to the whole spacing between adjacent fin edges.