摘要:
A process for producing water-absorbing polymer particles by neutralizing the monomer and cooling it by means of an indirect heat exchanger, wherein the specific cooling performance of the heat exchanger is less than 10 W/m2.
摘要翻译:通过中和单体并通过间接热交换器进行冷却来制造吸水性聚合物颗粒的方法,其中热交换器的比冷却性能小于10W / m 2。
摘要:
A process for continuously producing water-absorbing polymer particles, comprising polymerization, drying, grinding, classification and at least partial recycling of the undersize obtained in the classification, wherein the polymer gel obtained by the polymerization is withdrawn from the polymerization reactor and mixed with the recycled undersize.
摘要:
A process for pneumatic delivery of water-absorbing polymer particles using curved pipelines, the ratio of radius of curvature to tube diameter being at least 5.
摘要:
The invention relates to a neutralization process in which at least one ethylenically unsaturated carboxylic acid is neutralized at least partly with a base and at least one stream of the neutralization is determined continuously, and also to an apparatus for carrying out the process.
摘要:
Process for classifying a particulate water-absorbing resin using a sieving apparatus at a reduced pressure compared with the ambient pressure and a sieving apparatus for classifying a particulate water-absorbing resin at a reduced pressure compared with the ambient pressure.
摘要:
The present invention relates to novel (meth)acrylic esters of polyalkoxylated glycols of the formula where AO is independently at each instance is —O—CHR3-CHR4- or —CHR3-CHR4-O— where R3 and R4 are independently H, linear or branched C1-C8-alkyl, p1 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35, p2 is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35, n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 447, 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, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, R1 and R2 are independently H or CH3, wherein there is at least one AO in (AO)p1 and also at least one AO in (AO)p2 where R3 and R4 are not both H at one and the same time, a simplified process for preparing these esters and use of reaction mixtures thus obtainable.
摘要:
Foams composed of water-absorbing basic polymers, obtainable by (I) foaming a crosslinkable aqueous mixture including (a) at least one basic polymer whose basic groups have optionally been neutralized, (b) at least one crosslinker, (c) at least one surfactant, (d) optionally at least one solubilizer, (e) optionally thickeners, foam stabilizers, fillers, fibers and/or cell nucleators, and (f) optionally particulate water-absorbing acidic polymers, by dissolving a gas which is inert toward free radicals in the crosslinkable aqueous mixture under a pressure from 2 to 400 bar and subsequently decompressing the crosslinkable aqueous mixture to atmospheric or by dispersing fine bubbles of a gas which is inert toward free radicals, and (II) crosslinking the foamed mixture to form a hydrogel foam and if applicable adjusting the water content of the polymer foam to 1-60% by weight. Preparation of the foams by application of the abovementioned measures (I) and (II) and use of the thus obtainable foams in hygiene articles to absorb body fluids, in dressing material to cover wounds, as a sealing material, as a packaging material, as a soil improver, as a soil substitute, to dewater sludges, to absorb aqueous acidic wastes, to thicken waterborne paints or coatings in the course of disposing of residual quantities thereof, to dewater water-containing oils or hydrocarbons or as a material for filters in ventilation systems.
摘要:
Method for avoiding network defects due to unwanted secondary reactions during the polymerization in water-swellable hydrophilic polymers which contain polymers prepared by free radical (co)polymerization of one or more hydrophilic monomers of the formula I ##STR1## wherein R.sup.1 is hydrogen, methyl or ethyl, R.sup.2 is the group --COOR.sup.4, the sulphonyl group, the phosphonyl group, the phosphonyl group-esterified by (C.sub.1 -C.sub.4)-alkanol or a group of the formula ##STR2## R.sup.3 is hydrogen, methyl, ethyl or the carboxyl group, R.sup.4 is hydrogen, amino or hydroxy-(C.sub.1 -C.sub.4)-alkyl and R.sup.5 is the sulphonyl group, the phosphonyl group or the carboxyl group, or grafting (co)polymerization of one or more hydrophilic monomers of the formula I onto a grafting base, using a free radical initiator which forms three or more free radical sites per molecule.
摘要:
The present invention relates to a hydrophilic, highly swellable hydrogel based on (co)polymerized hydrophilic monomers or based on graft (co)polymers, characterized in that it has been surface-modified by means of a mixture ofA) one or more diglycidyl phosphonates andB) one or more other reactive compounds which are capable of reacting with the functional groups in the polymer, to a process for the preparation thereof, to the use thereof, and to diglycidyl phosphonate-containing crosslinking agent mixtures.
摘要:
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.