Abstract: A gas stove burner has a base defining an axis and a ring assembly sitting on the base, forming therewith an annular outer compartment and a central inner compartment, and formed with an array of outwardly open lower passages open radially inward into the outer compartment. A generally imperforate cover disk overlying the ring assembly has an outer edge, upwardly closes the inner compartment, and forms with the ring assembly an array of upper passages open radially inward into the inner compartment and radially outward at the disk outer edge. Inlets on the base feed respective gas/air mixtures to the compartments and form a main flame at the edge from the mixture exiting the lower passages and a simmer flame at the edge from the mixture exiting the upper passages.

Abstract: A soldering paste for hard-soldering and coating working parts made of aluminum or aluminum alloys, which contains 25 to 35 percent in weight of a water-miscible organic binding agent on the basis of aliphatic glycols, 25 to 45 percent in weight of an aluminum hard-soldering powder, 25 to 45 percent in weight of an aluminum fluxing agent and, as an additive to influence the rheological properties, 0.01 to 0.2 percent by weight with respect to the total amount of one or several fatty acids with 10 to 20 C atoms and/or their ammonium salts.

Abstract: A flux based on inorganic boron and/or halogen compounds for brazing difficult to wet metallic materials with silver- and copper-based solders, which contains, as an activating addition, based on the total amount of the flux, 0.01-10 wt. % of elemental boron and 0.01-10 wt. % of at least one of the elements Mo, W, Mn, Co, Ni, Pd, Cu or Ag in the form of elements, alloys or compounds. The activating addition brings about a substantial increase in the wettability by the solder, particularly in the case of difficult to wet stock materials.

Abstract: Block copolymers comprise at least two hard blocks S1 and S2 made from vinylaromatic monomers and, between these, at least one random soft block B/S made from vinylaromatic monomers and from dienes, where the proportion of the hard blocks is above 40% by weight, based on the total block copolymer.

Abstract: Block copolymers comprise at least two hard blocks S1 and S2 made from vinyl aromatic monomers and, between these, at least ore random soft block B/S made from vinyl aromatic monomers and from dienes, where the proportion of the hard blocks is above 40% by weight, based on the total block copolymer, wherein the 1,2-vinyl content in the soft block B/S is less than 20%.

Abstract: The invention relates to a catalytic process for carrying out multiphase reactions in a tubular reactor, with the catalyst being present in the continuous phase and at least one starting material in a disperse phase and the loading factor B of the tubular reactor being equal to or greater than 0.8. The process is especially suitable in particular for the hydroformylation of olefins. The aldehydes thus prepared can ideally be used for the preparation of alcohols, carboxylic acids or in aldol condensations.

Abstract: In a process for precipitating microsuspension polymers from a suspension comprising them, a polymer dispersion prepared by emulsion polymerization is added to the suspension.

Abstract: A process for preparing polymers which comprises conducting polymerization in the presence of free radicals of the formula I where Q is NR2 or S and T is CR3R4 or S and R1, R2, R3 and R4 can be identical or different and independently are hydrogen, C1- to C20-alkyl or C6- to C18-aryl.

Abstract: The invention relates t a flux-free brazing paste for the brazing of copper and copper alloys. The paste includes a binder consisting of a mixture of polyisobutene with a relative molar mass from 50,000 to 500,000 and paraffin within a melting-range from 40 to 90° C.

Abstract: The invention relates to a process for the catalytic aldol condensation of aldehydes by means of a multiphase reaction in a tube reactor, wherein the catalyst is present in the continuous phase and at least one aldehyde is present in a dispersed phase and the loading factor B of the tube reactor is equal to or greater than 0.8; the aldol condensation products obtained in this way can be used for preparing alcohols or carboxylic acids.

Abstract: 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.

Abstract: A gas stove burner has a base having an annular outer edge and a lower ring sitting on the base, forming therewith a lower compartment, and having an outer edge forming with the base outer edge an outwardly open annular slot communicating with the lower compartment. An upper ring sitting on the lower ring forms therewith an upper compartment and has an outer edge forming with the lower-ring outer edge an array of outwardly open holes communicating with the upper compartment. The upper-ring outer edge has a diameter generally equal to a diameter of the lower-ring outer edge. A gas/air mixture is fed to each of the compartments so that the gas will issue from the holes to form an upper flame and from the slot to form a lower flame of substantially the same diameter.

Abstract: A block copolymer obtainable by reacting A) monomers selected from the group consisting of styrene, &agr;-methylstyrene, acrylonitrile, methacrylonitrile, methyl methacrylate and maleic anhydride to form blocks A having a glass transition temperature Tg of more than 0° C. and B) monomers selected from the group consisting of n-butyl acrylate, methyl acrylate and 2-ethylhexyl acrylate to form blocks B having a glass transition temperature Tg of less than 0° C. at from 100 to 160° C. in the presence of free-radical initiators and N-oxyl radicals.

Abstract: A gas-valve assembly has a housing having an inlet port, an outlet port, and a passage extending between the ports and defining an axis, a valve plug rotatable about the axis in the housing in the passage between a closed end position blocking flow between the ports and an open end position permitting flow between the ports, and a control knob rotatable on the housing and angularly coupled to the valve plug. Structure engaged between the knob and the housing prevents the knob from moving axially relative to the housing while permitting rotation of the knob about the axis relative to the housing. A safety valve in the housing has a valve body displaceable axially between a closed position blocking flow through the passage and an open position permitting flow through the passage.

Abstract: A process for producing, on a metallic substrate, a geometric metal structure having a precise contour, including the steps of: solder coating a solder paste onto the substrate by screen printing to create the geometric metal structure, the solder paste comprising an organic binder system, and 80 to 95 weight % of a mixture of a nickel-based solder and a pulverulent alloy of nickel with at least one member selected from the group consisting of chromium, molybdenum, tungsten, manganese and iron, provided as a higher-melting metallic filler, wherein a weight ratio of solder to filler is 2-6:1, an average grain size of the solder is between 10 and 50 &mgr;m, and a grain size ratio of solder to filler, relative to the average grain size is from 0.5-2.5:1; drying the structure; decomposing the organic binder system present in the solder paste, without leaving a reside, by a heat treatment; and raising the temperature until the resulting solder material liquifies.

Abstract: Polyimides can be obtained by reacting a dianhydride component comprising 3,4,3',4'-bisphenyltetracarboxylic dianhydride, oxydiphthalic dianhydride and in addition further aromatic dianhydrides, and a diamine component comprising diamines of the formula ##STR1## and in addition further aromatic diamines.

Abstract: Stabilized polyaryl ether ketone molding compositions containing as essential componentsA) from 50 to 99.99% by weight of a polyaryl ether ketone prepared by electrophilic polycondensation and composed to an extent of not less than 50 mol % of units of the formula I' ##STR1## where s and t are each 0, 1, 2 or 3, T and T' are each --O-- or --CO-- and Ar is meta-phenylene, paraphenylene or two aromatic rings linked to each other in the meta or para position by a chemical bond, or the ring-substituted C.sub.1 -C.sub.8 -alkyl, C.sub.6 -C.sub.20 -aryl or halogen derivatives thereof,B) from 0.01 to 4% by weight of at least one organic compound which has a base constant pk.sub.b within the range from 2 to 12 and a boiling point of higher than 300.degree. C.,C) from 0 to 50% by weight of a further thermoplastic other than A), andD) from 0 to 45% by weight of fibrous or particulate fillers or mixtures thereof.

Abstract: A process for preparing polyaryl ethers of the formula I or Ia ##STR1## by condensation of at least one appropriate bisphenol with at least one appropriate aromatic dichloride in the presence of an alkali metal carbonate in a dipolar aprotic solvent, is carried out in the presence of a catalyst selected from the alkali metal nitrites and the group of compounds of the formula II ##STR2## where r.sup.1 and r.sup.3 are each hydrogen, C.sub.7 -C.sub.16 -phenylalkyl, C.sub.1 -C.sub.12 -alkoxy, fluorine, chlorine, bromine, iodine or nitro, and R.sup.2 is nitro or nitroso, or ##STR3## where R.sup.4 is hydrogen, C.sub.1 -C.sub.4 alkyl, fluorine, chlorine, bromine or iodine.

Abstract: An N-substituted polyamideimide essentially composed of identical or different repeating units of the formula I ##STR1## where R.sup.1 is one of the following tetravalent aromatic radicals ##STR2## and X is a bond or one of the following linkers ##STR3## where R.sup.2 and R.sup.4 are each, independently of one another, one of the following divalent aromatic radicals ##STR4## and where X has the abovementioned meanings and where R.sup.3 is hydrogen or a monovalent radical such as C.sub.1 -C.sub.6 -alkyl or phenyl, and the C.sub.1 -C.sub.6 -alkyl-, C.sub.1 -C.sub.6 -alkoxy-, aryl- or halogen-substituted derivatives thereof, and precursors (monomers) therefor, are described.

Abstract: An N-substituted polyamide-imide essentially composed of identical or different repeating units of the formula I ##STR1## where R.sup.1 is one of the following tetravalent aromatic radicals ##STR2## and X is a bond or one of the following linkers ##STR3## where R.sup.2 and R.sup.4 are each, independently of one another, one of the following divalent aromatic radicals ##STR4## and where X has the abovementioned meanings and where R.sup.3 is hydrogen or a monovalent radical such as C.sub.1 -C.sub.6 -alkyl or phenyl, and the C.sub.1 -C.sub.6 -alkyl-, C.sub.1 -C.sub.6 -alkoxy-, aryl- or halogen-substituted derivatives thereof, and precursors (monomers) therefor, are described.