Abstract:
A process for producing water-absorbing polymer particles, wherein at least one aliphatic aldehyde or reaction product thereof with an aliphatic alcohol, an aliphatic amine, ammonia, a hypophosphite or a phosphite is added.
Abstract:
Water-absorbing polymeric particles are produced by polymerizing a monomer solution or suspension comprising at least one unsaturated carboxylic acid, at least one hydroquinone monoether and at least one inorganic peroxide and coating the polymeric particles with at least one basic salt of a bivalent metal cation.
Abstract:
The invention relates to a process for producing a water-absorbing resin by polymerization of a reaction mixture comprising at least one hydrophilic monomer and, if appropriate, at least one crosslinker in a reactor, which comprises admixing the reaction mixture with at least one first portion of a particulate additive before the reaction mixture has reached a residence time of 40% of the overall residence time in the reactor and with at least one second portion of a particulate additive when the reaction mixture has reached a residence time of 45% or more of the overall residence time in the reactor, the additive being selected from water-absorbing resin powders, fillers and mixtures thereof, the total solids content of monomer and additive being in the range from 30% to 60% by weight, the amount of additive being in the range from 5% to 50% by weight, based on the monomers, and the weight ratio of the first portion to the second portion of the additive being in the range from 10:1 to 1:5. The resin powder is recycled fine-sized material for example. Not only the residual monomer content, specifically the residual crosslinker content, but also the level of extractables in the water-absorbing resin are reduced by the method of addition described. A high fraction of additives can be incorporated without the properties of the water-absorbing resin obtained being adversely affected. The additives enter a sufficiently firm bond with the resin, so that no excessive dusting occurs on exposure to mechanical stress.
Abstract:
The invention relates to finely divided water-absorbing polymeric particles having high fluid transportation and absorption performance, the Centrifuge Retention Capacity (CRC) being not less than 26 g/g, the absorbency under a load of 4.83 kPa (AUL0.7 psi) not less than 23 g/g and the Transportation Value (TV) not less than 15,000 cm3s, the Transportation Value (TV) being the product of Saline Flow Conductivity (SFC) and wicking absorption after 60 minutes (DA60) multiplied by 107, and wherein the wicking absorption after 60 minutes (DA60) is the weight of 0.9% by weight sodium chloride solution absorbed by 70 g of the water-absorbing polymeric particles in 60 minutes, wherein the water-absorbing polymeric particles are situated, during measurement, in a circularly round vessel which has an internal diameter of 6 cm and is sealed at its lower end by a sieve base of 36 μm mesh size, and the sieve base is in atmospheric contact with 0.9% by weight sodium chloride solution, processes for their preparation and also their use in hygiene articles and packaging materials.
Abstract:
Disclosed is a process for postcrosslinking a water absorbing polymer by the polymer being treated with at least one postcrosslinker and postcrosslinked and dried during or after the treatment by raising the temperature, the at least one postcrosslinker being a cyclic carbamate or a cyclic urea, wherein the cyclic carbamate or the cyclic urea was obtained by reacting respectively an aminoalcohol or a diamine with a cyclic carbonate.
Abstract:
Swellable hydrogel-forming polymer comprising at least one hydrophilic polymer of dendritic structure, a process for preparing the swellable hydrogel-forming polymer and also its use in hygiene articles.
Abstract:
The invention refers to absorbent structures for use in an absorbent article, the absorbent structure comprising a water absorbing material. The water absorbing material is obtainable by a process comprising the steps of bringing particles of a non surface-crosslinked water-absorbing polymer in contact with at least one post-crosslinker, at least one water-insoluble metal phosphate, and at least one further ingredient. The at least one ingredient is selected from at least one Nitrogen-containing water-soluble polymer, and at least one hydrophobic polymer. The particles are heat-treated at a temperature in the range from 120° C. to 300° C.
Abstract:
The invention refers to absorbent structures for use in an absorbent article, the absorbent structure comprising a water absorbing material. The water absorbing material is obtainable by a process comprising the steps of bringing particles of a non surface-crosslinked water-absorbing polymer in contact with at least one postcrosslinker, at least one Nitrogen-containing water-soluble polymer, and at least one hydrophobic polymer. The particles are heat-treated at a temperature in the range from 120° C. to 300° C.
Abstract:
The invention relates to a process for producing a water-absorbing resin by polymerization of a reaction mixture comprising at least one hydrophilic monomer and, if appropriate, at least one crosslinker in a reactor, which comprises admixing the reaction mixture with at least one first portion of a particulate additive before the reaction mixture has reached a residence time of 40% of the overall residence time in the reactor and with at least one second portion of a particulate additive when the reaction mixture has reached a residence time of 45% or more of the overall residence time in the reactor, the additive being selected from water-absorbing resin powders, fillers and mixtures thereof, the total solids content of monomer and additive being in the range from 30% to 60% by weight, the amount of additive being in the range from 5% to 50% by weight, based on the monomers, and the weight ratio of the first portion to the second portion of the additive being in the range from 10:1 to 1:5. The resin powder is recycled fine-sized material for example. Not only the residual monomer content, specifically the residual crosslinker content, but also the level of extractables in the water-absorbing resin are reduced by the method of addition described. A high fraction of additives can be incorporated without the properties of the water-absorbing resin obtained being adversely affected. The additives enter a sufficiently firm bond with the resin, so that no excessive dusting occurs on exposure to mechanical stress.
Abstract:
A mixture of at least two compounds each having at least two double bonds, said mixture having a WFR from 200 to 600 g/mol of double bond and at least two of said compounds each comprising at least two (meth)acrylic esters as double bond component, WFR being given by: ∑ i = 1 n α i ⨯ MW i / Z i = WFR where ∑ i = 1 n α i = 1 αi is equal to the molar fraction of compound (i) in said mixture,n is equal to the number of compounds in said mixture and n is ≧2,Zi is equal to the number of double bonds in said compound (i),MWi is equal to the molecular weight of said compound (i).