Abstract: A process for producing water-absorbing polymer particles, wherein surface postcrosslinked water-absorbing polymer particles are remoisturized and classified, and wherein the time between remoisturization and classification is at least 15 minutes.

Abstract: A process for producing water-absorbing polymer particles, wherein surface postcrosslinked water-absorbing polymer particles are remoisturized and delivered pneumatically, and wherein the time between remoisturization and pneumatic delivery is less than one hour.

Abstract: A process for continuously producing water-absorbing polymer particles, comprising polymerization of a monomer solution or suspension on a continuous belt, drying, grinding, classifying and at least partly recycling the undersize obtained in the classification, wherein the recycled undersize is mixed with the monomer solution or suspension.

Abstract: A process for removing metallic impurities from a product mass flow comprising water-absorbing polymer particles by means of bar magnets, wherein the water-absorbing polymer particles comprise a surfactant and have direct contact with the bar magnets.

Abstract: A process for producing water-absorbing polymer particles, comprising classification by means of a tumbler screening machine, wherein the tumbler screening machine used for classification is equipped with at least one ball knock cleaning system and entrained balls are removed outside the tumbler screening machine by means of a capture device.

Abstract: A process for producing water-absorbing polymer particles, wherein an aqueous polymer gel is dried in a forced-air belt drier on a circulating conveyor belt and the surface of the conveyor belt has a roughness of at least 0.9 ?m.

Abstract: The invention relates to processes for preparing water absorbing polymers by polymerization of a monomer solution comprising allyl acrylate and/or allyl alcohol, the solution comprising not more than 0.002% by weight of allyl acrylate and/or allyl alcohol, based on acrylic acid, to aqueous monomer solutions for producing water absorbing polymers, to water absorbing polymers, to processes for producing hygiene articles and also to hygiene articles.

Abstract: A process for producing water-absorbing polymeric particles comprises conducting the polymerization in at least two parallel continuous polymerization reactors under substantially identical conditions and further processing the reaction products conjointly in at least one process step.

Abstract: The invention relates to a measuring device for measuring the degree of transmission of a coating on a glass plate. The glass plate rests on a support relative to which it is shifted. The support is provided with a gap enabling a light beam to pass through the glass plate and to impinge on a light receiver. Thus, the degree of transmission of the coating can be determined. Further, the reflection and the electric resistance of the coating can be measured by the measuring device.

Abstract: A process for cleaning apparatus in which (meth)acrylic acid-containing organic solvents have been treated and/or generated and contain fouling and/or polymer and residues of organic solvent, in which the apparatus contents are subjected to a steam distillation in the apparatus.

Abstract: The present invention relates to novel (meth)acrylic esters of polyalkoxylated trimethylolpropane of the formula where EO is O—CH2-CH2- PO is independently at each instance O—CH2-CH(CH3)- or O—CH(CH3)-CH2- n1, n2 and n3 are independently 4, 5 or 6, n1+n2+n3 is 14, 15 or 16, m1, m2 and m3 are independently 1, 2 or 3, m1+m2+m3 is 4, 5 or 6, R1, R2 and R3 are independently H or CH3, a simplified process for preparing these esters and the use of reaction mixtures thus obtainable.

Abstract: The present invention relates to novel (meth)acrylic esters of polyalkoxylated trimethylolpropane of the formula where AO is for each AO independently at each instance EO, PO or BO where EO is O—CH2-CH2- PO is independently at each instance O—CH2-CH(CH3)- or O—CH(CH3)-CH2- BO is independently at each instance O—CH2-CH(CH2-CH3)- or O—CH(CH2-CH3)-CH2- p1+p2+p3 is 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74 or 75, R1, R2 and R3 are independently H or CH3, a simplified process for preparing these esters and the use of reaction mixtures thus obtainable.

Abstract: In a process for rectificatively separating liquids comprising (meth)acrylic monomers in a rectification column, a stream is withdrawn from the rectification column and recycled into the rectification column as a molecular oxygen-enriched liquid phase.

Abstract: Higher (meth)acrylates IV are prepared by transesterification of a lower (meth)acrylate I with a higher alcohol R2OH in the presence of a stabilizer or stabilizer mixture and of a catalyst or catalyst mixture, by a process in which the liberated lower alkanol R1OH is separated off and is fed at least partly to the preparation of the lower (meth)acrylate I.

Abstract: Organic compounds are prepared by heterogeneously catalyzed partial gas-phase oxidation of precursor compounds by a process in which a portion of the reaction gas starting mixture is brought from a low initial pressure to a higher final pressure by means of a radial compressor.

Abstract: In a process for preparing acrylic acid, an acrylic acid-containing product gas mixture obtained by catalytic gas phase partial oxidation of a C3 precursor of acrylic acid, after direct cooling with a quench liquid, is fractionally condensed in a separating column provided with internals, rising into itself with sidestream takeoff of crude acrylic acid, and the acrylic acid oligomers which form are dissociated and the resulting dissociation gas is subjected to a countercurrent rectification before it is recycled.

Abstract: The present invention describes a process for preparing (meth)acrylic esters by acid-catalyzed esterification of (meth)acrylic acid or by transesterification of (meth)acrylic esters with alcohols, by adding the (meth)acrylic acid or the (meth)acrylic ester at a metering rate of less than 250 g per hour and liter of reactor volume and/or using at least 0.2 mmol of polymerization inhibitor per kg of alcohol and per meq/kg of peroxid number of the alcohol determined by the Sully method and/or thermally treating the alcohol in the absence of water before the esterification or transesterification.

Abstract: In a process for preparing an ester of an unsaturated carboxylic acid by reacting an ester of the unsaturated carboxylic acid and a C1-C4-alkanol with an alcohol R3OH, where R3 is a C4-C20-alkyl radical, a C5-C7-cycloalkyl radical, a phenyl-C1-C4-alkyl radical or a C2-C12-alkyl radical substituted by at least one NR5R5 group or by from 1 to 3 hydroxyl groups or C1-C4-alkoxyl groups or interrupted by one or more oxygen atoms, where the radicals R5 are, independently of one another, C1-C6-alkyl or together with the nitrogen atom form a 5- to 7-membered heterocyclic ring which may contain a further nitrogen or oxygen atom, in the presence of a transesterification catalyst, the transesterification catalyst used is at least one metal alkanolate containing at least one OR1 group, where R1 is a 2,2,6,6-tetraalkyl-1-oxylpiperidin-4-yl radical.

Abstract: Mixtures containing monomers having at least one ethylenically unsaturated group are chemically and/or physically treated in the presence of the reaction products of alkylsuccinic anhydrides and stable N-oxyl radicals having a hydroxyl group.

Abstract: The invention relates to a method for producing (meth)acrylic acid esters by transesterification of the (meth)acrylic acid with a higher alkanol in the presence of an acid catalyst, at least one polymerization inhibitor and one organic solvent that forms an azeotropic mixture with water. The reaction mixture is heated to the boiling point of the mixture in a reactor that comprises a distillation unit with a column and a condenser. The content of the reactor is recirculated via an external evaporator and heated to the boiling point, and the azeotropic mixture is distilled off. The organic solvent forms a reflux and at least a part of the solvent reflux is recirculated between the reactor and the evaporator. The inventive method allows for the production of higher (meth)acrylic acid esters in a reactor with a circulation evaporator without using copper salts as the polymerization inhibitors.