Abstract:
The invention relates to a method for producing a water-absorbing resin by polymerization of a reaction mixture comprising at least one hydrophilic monomer and optionally at least one cross-linker, in a reactor. According to said method, at least one first fraction of a particulate additive is admixed to the reaction mixture before the reaction mixture reaches a dwell time of 40 % of the total dwell time in the reactor, and at least one second fraction of a particulate additive is admixed when the reaction mixture reaches a dwell time of 45 % or more of the total dwell time in the reactor. The additive is selected from the group of water-adsorbing resin powders, fillers and mixtures thereof, the total solids content of the monomer and the additive being 30 to 60 % by weight, the amount of the additive being 5 to 50 % by weight, based on the monomer, and the weight ratio of the first fraction to the second fraction of the additive being 10:1 to 1:5. The resin powder is constituted of, e.g., recycled fines. Bot the residual monomer content, especially the residual cross-linker content, and the content in extractable substances of the water-absorbing resin are reduced by the described manner of admixture. A high percentage of additives can be incorporated without deteriorating the properties of the water-absorbing resin so obtained. The additives form a sufficiently strong compound with the resin without excessive dust formation when the resin is exposed to mechanical stress.
Abstract:
The invention relates to a cross-linked, water-swellable polymer that contains polymerized into it moieties of a) water-soluble, monoethylenically unsaturated monomers, and b) 0.001 to 5 mole % based on the monomers a) of a cross-linking combination, b1) a first cross-linking agent with at least two (meth)acrylic ester moieties in the molecule and b2) a second cross-linking agent with at least two (meth)allyloxy moieties in the molecule, the molar ratio of b1) to b2) ranging from 0.7:1 to 10:1. The polymer according to the invention has a balanced property profile as regards absorptivity, gel strength, absorption speed and extractable components and can be advantageously produced by a continuous method.
Abstract:
The present invention relates to novel hydrophilic swellable addition polymers comprising improved odor control, a process for their preparation and their use for absorbing aqueous fluids and a process for screening superabsorbents.
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:
Preparation of water-absorbing resin by polymerization of a reaction mixture comprising at least one hydrophilic monomer and optionally at least one cross-linker, comprises mixing at least a first portion of a particulate additive in the reaction mixture, before the reaction mixture reaches a retention time of 40% of the total retention time in the reactor; and mixing at least a second portion of a particulate additive in the reaction mixture, when the reaction mixture reaches a retention time of 45% or more of the total retention time in the reactor. Preparation of water-absorbing resin by polymerization of a reaction mixture comprising at least one hydrophilic monomer and optionally at least one cross-linker, in a reactor, comprises mixing at least a first portion of a particulate additive in the reaction mixture, before the reaction mixture reaches a retention time of 40% of the total retention time in the reactor; and mixing at least a second portion of a particulate additive in the reaction mixture, when the reaction mixture reaches a retention time of 45% or more of the total retention time in the reactor, where: the additive is a water-adsorbing resin powder and/or filler; the total solid content of the monomer and additive is 30-60 wt.%; the amount of the additive is 5-50 wt.%, based on the monomer; and the weight ratio of the first fraction to the second fraction of the additive is 10:10-1:5.
Abstract:
The invention relates to a cross-linked, water-swellable polymer that contains polymerized into it moieties of a) water-soluble, monoethylenically unsaturated monomers, and b) 0.001 to 5 mole % based on the monomers a) of a cross-linking combination, b1) a first cross-linking agent with at least two (meth)acrylic ester moieties in the molecule and b2) a second cross-linking agent with at least two (meth)allyloxy moieties in the molecule, the molar ratio of b1) to b2) ranging from 0.7:1 to 10:1. The polymer according to the invention has a balanced property profile as regards absorptivity, gel strength, absorption speed and extractable componenents and can be advantageously produced by a continuous method.
Abstract:
Water-swellable hydrophilic (co)polymer powder contains additive(s) to reduce dust. The additive comprises silicone(s) and/or a total of less than 1 wt.% fatty alcohols or their esters, fatty acids or their opt. sulphated esters or amides, sulphosuccinic esters, polyols, polyglycols or their ethers, aliphatic hydrocarbons and/or paraffin oils. The individual additives have a vapour pressure of at most 0.1 mbar at 20 degrees C and m.pt. of max. 100 degrees C. Also claimed is a method of producing the treated powder.
Abstract:
1,4,6,9-Tetraoxa-5-silaspiro(4.4)nonanes (diglycol silicates) (I) are used as crosslinking agents for surface crosslinking of particles of superabsorbing polymer. 1,4,6,9-Tetraoxa-5-silaspiro(4.4)nonanes (diglycol silicates) of formula (I) are used as crosslinking agents for surface crosslinking of particles of superabsorbing polymer: R, R' = hydrogen (H) or 1-6 carbon (C) alkyl. An Independent claim is also included for surface-crosslinked superabsorbing polymer produced in this way.
Abstract:
Resení se týká zasítovaného, vodou bobtnatelného polymeru, který obsahuje jako polymerované soucásti a) ve vode rozpustné, monoethylenove nenasycené monomery, a b) 0,001 do 5 % mol., vztazeno k monomerum a), kombinace b1) prvního zesítujícího cinidla s alespon dvema (meth)akrylesterovými cástmi v molekule a b2) druhého zesítujícího cinidla s alespon (meth)allyloxy cástmi v molekule, pricemz molární pomer b1) vzhledem k b2) se pohybuje v rozmezí od 0,7:1 do 10:1. Polymer podle predlozeného resení má vyrovnaný profil vlastností, predevsím pohltivosti, pevnosti gelu, absorpcní rychlosti a podíluextrahovatelných komponent a muze být s výhodou pripraven kontinuální metodou.