Abstract: A safety circuit for valves actuated hydraulically via a positioning cylinder. The positioning cylinder in one embodiment is configured to be hydraulically or pneumatically depressurized in an emergency. The positioning cylinder has two cylinder chambers configured to be fluidically connected via a working line. A first and a second series-connected shut-off valve are provided in the working line. The positioning cylinder in another embodiment is configured to be hydraulically or pneumatically actuated in an emergency. The positioning cylinder has at least one first cylinder chamber configured, in an emergency, to be supplied with pressurized fluid via a first pressure medium flow path. A first and a second series-connected shut-off valve are provided in the first pressure medium flow path.

Abstract: A safety circuit for valves actuated hydraulically via a positioning cylinder. The positioning cylinder in one embodiment is configured to be hydraulically or pneumatically depressurized in an emergency. The positioning cylinder has two cylinder chambers configured to be fluidically connected via a working line. A first and a second series-connected shut-off valve are provided in the working line. The positioning cylinder in another embodiment is configured to be hydraulically or pneumatically actuated in an emergency. The positioning cylinder has at least one first cylinder chamber configured, in an emergency, to be supplied with pressurized fluid via a first pressure medium flow path. A first and a second series-connected shut-off valve are provided in the first pressure medium flow path.

Abstract: A multilayered lightweight building board, comprising a support core, two cover layers on the support core, where the support core is made of laterally fused-together tubes. The tubes have an inner layer, and an outer layer, where the outer layer has a softening point 10-90.degree. C. lower than the softening point of the inner layer. The lightweight building board is made from compatible thermoplastic materials, so they can be mechanically recycled by the customary processing methods for thermoplastics.

Abstract: Molding compounds comprising aromatic polyamides which contain from 0.001 to 10% by weight of a low molecular weight sulfonic acid amide display low melt viscosities and an increased resistance to hydrolysis and are thermoplastically processible.

Abstract: Molding compounds comprisign aromatic polyamides which contain from 0.01 to 10 mole % of a low molecular weight carboxylic acid amide display low melt viscosities and an increased resistance to hydrolysis and are thermoplastically processible.

Abstract: Reducing 3,3', 5,5'-tetra-t-butyldiphenoquinone with 2,6-di-t-butylphenol, in the melt, in the presence of a 4-dialkylaminopyridine, and then dealkylating the intermediate formed, in the melt, by adding a phosphorus-containing acid or its derivative provides 4,4'-dihydroxybiphenyl of high purity in high yield.

Abstract: A molding material comprising an imide group-containing aromatic polyamide, obtained by polycondensation of(A) an aromatic diamine of the general formulaH.sub.2 N--Ar--O--Ar'--X--Ar'--O--Ar--NH.sub.2wherein Ar and Ar' are m- or p-phenylene groups and X is --SO.sub.2 -- or --CO--, with at least one aromatic dicarboxylic acid B) selected from the group consisting of(B1) a mixture comprising 40 to 100 mole % of an acid of the structure ##STR1## and 60 to 0 mole % of an acid of the structure ##STR2## in which n is 0-4 and R is selected from the group consisting of (a) an alkyl group having 1-6 carbon atoms,(b) an unsubstituted phenyl or an alkyl- or aryl substituted phenyl group,(c) an alkoxy group having 1-6 atoms,(d) a phenoxy group, in which the phenyl ring is unsubstituted or is alkyl- or aryl substituted, and(e) a halogen,(B2) an acid of the structure ##STR3## and (B3) a dicarboxylic acid of the formulaHO.sub.2 C--Ar--(A--Ar).sub.p --CO.sub.2 Hwherein Ar is m-phenylene or p-phenylene, A=--O--, --S--, --SO.

Abstract: A molding composition, comprising an aliphatic/aromatic copolyamide polymer having statistically distributed throughout the polymer:(A) from greater than 40 to less than 100 mole % aliphatic monomer units containing amino groups, carboxyl groups or mixtures thereof; and(B) up to 60 mole % of aromatic monomer units containing amino groups, carboxy groups or mixtures thereof, said aromatic monomer units containing at least one member selected from the group consisting of 4,4'-bis(4-aminophenoxy)diphenyl sulfone, 4,4'-bis(3-aminophenoxy)diphenyl sulfone, 4,4'-bis(4-aminophenoxy)benzophenone, and 4,4'-bis(3-aminophenoxy)benzophenone.

Abstract: A molding material, comprising the following monomer units:(A) 10-80 mole % HO--AR--COOH,(B) 0-40 mole % HOOC--Ar'--COOH,(C) 10-45 mole % HO--Ar"--OH, and(D) 5-45 mole % ##STR1## wherein Ar, Ar', and Ar", independently, are 1,3- or 1,4-phenylene; 1,4-, 1,5-, 2,6- or 2,7-naphthylene or ##STR2## wherein X is --O--, --S--, --SO.sub.2 -- or --CR.sub.2 --, R is H or C.sub.1-4 alkyl, and n is 0 or 1, wherein all monomer unit quantities relate to the sum of components A-D and their sum is 100 mol %, and wherein the molar ratio (B+D):C ranges from about 0.9:1 to 11.1:1.

Abstract: A high molecular weight aromatic polyamide molding composition prepared by the polycondensation reaction of:(A) An aromatic diamine of the formula:H.sub.2 N--AR'--O--Ar"--CO--Ar"--O--Ar'--NH.sub.2wherein Ar' and Ar" are meta- or para-phenylene, and wherein up to 70 mole % of said aromatic diamine can be replaced by a second aromatic diamine having the formula:H.sub.2 N--Ar--((Z).sub.q --Ar).sub.r --NH.sub.2wherein Ar is meta- or para-phenylene, Z is identical or different radicals selected from the group consisting of --O--, --S--, --SO.sub.2 --, --CO--, and --C(CH.sub.3).sub.2 --, q is 0 or 1, and r is 0, 1 or 2, with(B) An aromatic dicarboxylic acid selected from the group consisting of:(i) isophthalic acid, wherein up to 60 mole % of said isophthalic acid may be replaced with terephthalic acid, wherein said isophthalic acid and said terephthalic acid may be ring substituted with one or more substituents selected from the group consisting of C.sub.1-6 alkyl, phenyl, alkyl or aryl substituted phenyl, C.sub.

Abstract: The invention relates to aromatic polyamides and polyamidimides, and a method of manufacturing these by transamidation of aromatic biasmides of carboxylic acids, using aromatic di- and/or tricarboxylic acids or their anhydrides, in the melt, at temperatures between 220.degree. to 390.degree. C.

Abstract: The invention relates to a process for producing aromatic polyamides by melt condensation of(i) aromatic diamines of the formulaH.sub.2 N--Ar'--X--Ar"--Y--Ar"--X--Ar--NH.sub.2where X=--O-- and Y=--SO.sub.2 -- or X=--SO.sub.2 -- and Y=--O-- and Ar' and Ar"=meta-, para-phenylene, which can be replaced up to 70 mole percent by an aromatic diamine of the formulaH.sub.2 N--Ar--((Z)q--Ar).sub.r --NH.sub.2where Ar=meta-- or para-phenylene; Z=--O--, --S--, --SO.sub.2 --, --CO--, or --C(CH.sub.3).sub.2 -- or mixtures thereof; q=0 or 1; r=0, 1 or 2 and of(ii) isophthalic acid, which can be replaced up to 60 mole % by terephthalic acid, while both acids can be substituted for by an acid with the formula ##STR1## or a dicarboxylic acid with the general formulaHO.sub.2 C--Ar--(A--Ar).sub.p --CO.sub.2 H,where A=--O--, --S--, --SO.sub.2 --, --CO-- or a single bond; and p=0 or 1; in the presence of triphenylphosphite or an acid with the formula H.sub.3 PO.sub.n, where n=2, 3 or 4.