Abstract: A process for preparing trioxane by trimerization of formaldehyde in aqueous acidic solution and subsequently removing trioxane from a mixture substantially comprising trioxane, water and formaldehyde (crude trioxane product), which comprises a) distilling the crude trioxane product from the trimerization, b) crystallizing the trioxane out and c) removing it from the mother liquor and d) subsequently melting it and e) distilling off further by-products.

Abstract: Moldings based on polyamides are surface treated with mixtures of at least 20% strength by weight aqueous hydrochloric acid with mono- or diethers of an aliphatic polyfunctional hydroxy compound in a mixing ratio of from 90:10 to 10:90% by volume.

Abstract: Thermoplastic molding materials containA) from 40 to 99.69% by weight of a polyoxymethylene homo- or copolymer,B) from 0.1 to 2% by weight of at least one stabilizer selected from the group consisting of benzotriazole derivatives or benzophenone derivatives or aromatic benzoate derivatives,C) from 0.1 to 2% by weight of at least one sterically hindered amino compound,D) from 0.005 to 2% by weight of a polyamide,E) from 0 to 2% by weight of an epoxy-containing compound,F) from 0 to 50% by weight of a toughened polymer andG) from 0 to 50% by weight of a fibrous or particulate filler or of a mixture thereof.

Abstract: A thermoplastic molding material based onA) from 2 to 97.5% w/w of a homopolymer or copolymer of polyoxymethyleneB) from 2 to 97.5% w/w of a polyamideC) from 0.5 to 25% w/w of a polycondensate of 2,2-di(4-hydroxyphenyl)propane and epichlorohydrinD) from 0 to 60% w/w of an impact modifier, andE) from 0 to 60% w/w of fibrous or particulate fillers or mixtures thereof.

Abstract: A process for the surface treatment of moldings based on liquid crystalline polymers with acidic or alkaline reagents includes using the reagents in a solvent which is an organic solvent to an extent of not less than 60% by weight.

Abstract: Thermoplastic molding compositions suitable for producing interior components for vehicles for the conveyance of passengers, in particular aircraft, which show a low smoke gas density and low heat release characteristics in the event of a fire, are based on a heat-resistant plastic which contains as a filler from 0.5 to 50 % by weight of an oxide of an element of main group III, IV or V, of a salt of an oxygen acid of an element of main group III, IV or V or of a compound which on heating forms such an oxide or salt.

Abstract: Thermoplastic molding compositions suitable for producing interior components for vehicles for the conveyance of passengers, in particular aircraft, which show a low smoke gas density and low heat release characteristics in the event of a fire, are based on a heat-resistant plastic which contains as a filler from 0.5 to 50% by weight of an oxide of an element of main group III, IV or V, of a salt of an oxygen acid of an element of main group III, IV or V or of a compound which on heating forms such an oxide or salt.

Abstract: A polymeric molding composition contains(a) 20-70% by weight of a thermotropic, liquid-crystalline polymer(b) 10-50% by weight of a polycarbonate(c) 10-50% by weight of a polyester, the weight percentages (a), (b) and (c) adding up to 100, and(d) up to 60% by weight, based on the total amount of proportions (a), (b) and (c), of further polymers, fillers, reinforcing agents, processing aids or other additives, and is used for producing moldings, fibers, films or coatings.

Abstract: Thermoplastic molding materials which are stable at high temperatures and are based on polyaryl ether sulfones and, if required, polyether ketones have a content of alkali metal salts of not more than 100 ppm, based on total polymer.

Abstract: Thermoplastic molding compositions suitable for producing interior components for vehicles for the conveyance of passengers, in particular aircraft, which show a low smoke gas density and low heat release characteristics in the event of a fire, are based on a heat-resistant plastic which contains as a filler from 0.5 to 50% by weight of an oxide of an element of main group III, IV or V, of a salt of an oxygen acid of an element of main group III, IV or V or of a compound which on heating forms such an oxide or salt.

Abstract: Fiber-reinforced materials are produced by a process in which a heat-stable thermoplastic aromatic polyether A containing reactive groups, preferably nitrile groups and/or sulfur bridges and/or arylthio or alkylthio groups, if required together with a heat-stable thermoplastic polymer B which does not contain any reactive groups, is applied onto reinforcing fibers, the resulting semi-finished product is shaped, and the plastic matrix in the molding obtained is crosslinked so that there is virturally no increase in its glass transition temperature although the amount of soluble material is decreased to less than 60%, determined by extraction in boiling dichloromethane for one hour.

Abstract: High temperature resistant molding materials containing(A) 5-95 mol % of blocks having the structural unit I ##STR1## (B) 5-95 mol % of blocks having the structural unit II ##STR2## (C) 0-80 mol % of blocks having the structural unit III ##STR3## the molecular weight of the blocks being within the range 2000-20,000, where X is --O--, --S--, ##STR4## (only if a or b.noteq.0), ##STR5## (R.sup.7 =R.sup.8 =CH.sub.3 only if a or b.noteq.O) or a chemical bond, R.sup.7 and R.sup.8 are each alkoxy or alkyl of 1-6 carbon atoms, aryl or hydrogen, Q and W are each ##STR6## Z is --O-- or a chemical bond and R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each alkyl or alkoxy of 1-6 carbon atoms, aryl, Cl or F and p, q and r are each 0 or 1 and a, b, c, d and e are each 0, 1, 2, 3 or 4.

Abstract: Fiber-reinforced materials are produced by a process in which a heat-stable thermoplastic aromatic polyether A which contains reactive groups, preferably nitrile groups and/or sulfur bridges and/or arylthio or alkylthio groups, if necessary together with a heat-stable thermoplastic polymer B which does not contain any reactive groups, is applied onto reinforcing fibers, the resulting semi-finished product is molded and, in the molding obtained, the plastic matrix is crosslinked so that the glass transition temperature increases and it becomes virtually insoluble.

Abstract: Thermoplastic molding materials containing a mixture ofA. a heat-stable polymer, e.g. a polyether sulfone or polysulfone, which does not contain any reactive groups, andB. a heat-stable polymer which contains reactive groups, preferably nitrile or thioaryl groups and/or sulfur bridges,can be processed to moldings, which can be crosslinked, for example by being heated at above 200.degree. C., so that the plastic matrix becomes virtually insoluble.

Abstract: Fiber-reinforced materials are produced by impregnating continuous filaments with a melt of a polyarylene sulfide ketone, preferably one having a reduced viscosity .eta..sub.red of from 0.1 to 0.5 [dl.g.sup.-1 ], shaping the resulting semi-finished product to give a finished article and heating the latter for not less than 15 minutes at above the crystallite melting point of the polyarylene sulfide ketone, the latter undergoing crosslinking and its glass transition temperature Tg increasing by not less than 5.degree. C.