摘要:
A crosscurrent heat exchanger body made up of a stack of joined, parallel flow web plates (1), and a hollow chamber (5) for flow across them between each two successive web plates, with the cover layers (2,2') of successive web plates being sloped toward one another at their ends over the hollow chamber (5) enclosed between them, and being joined tightly to one another over the entire width, is disclosed.
摘要:
Agglomerated particles of water-swellable addition polymers, the agglomerated particles having an average particle diameter of from 20 to 5000 &mgr;m and consisting of primary particles having an average particle diameter of from 0.1 to 15 &mgr;m, being preparable by polymerization of water-soluble monomers in the presence of from 1′ to 10% by weight of a regulator and at least 2000 ppm, each based on the monomers, of a crosslinking agent in the manner of a water-in-oil polymerization and subsequent azeotropic removal of water from the water-in-oil polymer emulsions, containing the primary particles, in the presence of agglomerating polyalkylene glycols which (a) are obtainable by an addition reaction of C2-C4-alkylene oxides with alcohols, phenols, amines or carboxylic acids, and (b) contain at least 2 polymerized alkylene oxide units, and disintegrating into the primary particles on introduction into an aqueous medium, processes for preparing the agglomerated polymer particles and use of the agglomerated particles as thickeners for print pastes.
摘要:
Graft polymers which contain N-vinyl units and in which the grafting base is a polymer which contains in each case at least 5% by weight of units of the formulae ##STR1## where R.sup.1 and R.sup.2 are each H or C.sub.1 -C.sub.6 -alkyl, monoethylenically unsaturated monomers are grafted onto the grafting base in a weight ratio of from 100:1 to 1:100, and which have K values of at least 7 (determined according to H. Fikentscher in 5% strength by weight aqueous solution at 25.degree. C. and pH 7), are prepared by polymerization of monoethylenically unsaturated monomers in the presence of polymers which in each case contain at least 5% by weight of units of the formulae I and/or II as the grafting base in a weight ratio of from 100:1 to 1:100, and are used as dispersants for pigments, as additives for detergents and cleaning agents, and strength agents for paper and as soil stabilizers and for fertilizer compaction.
摘要:
Nitrile impurities are eliminated from polymers which contain acyclic N-vinyl-carboxamide and/or vinylamine units by treating the polymers with at least one oxidizing agent a) with exposure to light and/or b) in the presence of heavy metal ions.
摘要:
Reaction products of polybasic acids and amino-containing compounds, which are obtainable by heating a mixture of (a) a polybasic carboxylic acid selected from the group consisting of citric acid, isocitric acid, aconitic acid, itaconic acid and/or tartaric acid and (b) an amino-containing compound in a molar ratio of (a) to (b) of from 1:0.1 to 1:10 to at least 80.degree. C. are used as additives in low-phosphate and phosphate-free detergents and cleaning agents.
摘要:
Graft polymers are obtainable by free radical polymerization of(A) monomers or monomer mixtures of(a) from 10 to 100% by weight of open-chain N-vinylcarboxamides(b) from 0 to 90% by weight of other, carboxyl-free monoethylenically unsaturated monomers which are copolymerizable with the monomers (a) and(c) from 0 to 5% by weight of monomers containing two or more ethylenically unsaturated, non-conjugated double bonds in the molecule, in the presence of(B) natural substances containing saccharide structures, such as mono-, oligo- and polysaccharides,in a weight ratio (A):(B) of from 95:5 to 20:80 and, if required, subsequent hydrolysis of the amido groups of the polymerized monomers (a) of the graft polymer with formation of amino groups, and said polymers are used as dry and wet strength agents for paper, board and cardboard.
摘要:
Water-in-oil emulsions of water-soluble or water-swellable polymers, in which the oil phase of the emulsion consists of not less than 50% by weight of an oil of vegetable or animal origin, contain, as water-in-oil emulsifiers, compounds which are obtainable by(A) reacting a C.sub.10 -C.sub.22 -fatty alcohol with epichlorohydrin in a molar ratio of from 1:0.5 to 1:1.5 to give a glycidyl ether,(B) reacting the glycidyl ether with (1) a saturated C.sub.2 -C.sub.6 -alcohol containing from 2 to 6 OH groups or (2) the monoether thereof with a C.sub.10 -C.sub.22 -fatty alcohol, in a molar ratio of glycidyl ether to (1) or (2) of from 1:0.5 to 1:6, in the presence of an acid or base and(C) alkoxylating the reaction product from (B) with one or more C.sub.2 -C.sub.4 -alkylene oxides in a molar ratio of from 1:1 to 1:6,if necessary, from 5 to 95% by weight of the stated water-in-oil emulsifier being replaced with other water-in-oil emulsifiers.
摘要:
N-vinylformamide is polymerized with or without other water-soluble monoethylenically unsaturated monomers and with or without water-insoluble monoethylenically unsaturated monomers in not less than 30% strength by weight aqueous monomer solutions in the presence of a polymerization initiator at not more than 150.degree. C. in a kneader by a method in which the polymerization is carried out to such an extent that the initially formed water-containing polymer gel disintegrates into fine particles and the finely divided polymer obtainable in this manner is hydrolyzed, preferably in the kneader, so that not less than 0.1 mol % of the N-vinylformamide units present in the polymer are converted into vinylamine units. The polymers obtainable in this manner dissolve readily in water. The aqueous solutions are used, for example, in papermaking and tertiary oil production.
摘要:
Nonhydrolyzed copolymers of(a) from 99 to 1 mol % of N-vinylformamide and(b) from 1 to 99 mol % of one or more water-soluble dialkylaminoalkylacrylamides in the form of the salts or quaternized products or a dialkylammonium compoundare used as agents for the treatment of wastewaters and sludges.
摘要:
A process for the preparation of copolymers which contain monoethylenically unsaturated monocarboxylic acids and dicarboxylic acids as copolymerized monomer units, which comprises copolymerizinga) 10 to 60% by weight, based on the sum of the monomers, of a monoethylenically unsaturated dicarboxylic acid of 4 to 6 carbon atoms, -or an alkali metal salt thereof or, an anhydride thereof,b) 90 to 40% by weight of a monoethylenically unsaturated monocarboxylic acid of 3 to 10 carbon atoms or an alkali metal salt thereof andc) 0 to 20% by weight of another monoethylenically unsaturated monomer, not having carboxyl groups and which is copolymerizable with a) and b);in an aqueous medium in the presence of from 0.5 to 5% by weight, based on monomers, of a water-soluble initiator.