摘要:
A process for producing thin absorbent planar structures which may be used in hygiene products such as diapers, incontinence products, wound contact materials or sanitary napkins to absorb body fluids, comprises the steps of: A) producing a mixture of an adhesive in dispersion form and a particulate absorbent by fluidizing the components, B) applying the mixture of adhesive and absorbent uniformly to the surface of one side of a first planar backing material, C) one side of a second planar backing material is applied to the mixture of adhesive and absorbent that is present on the surface of one side of the first planar backing material, so producing a sandwichlike intermediate, and D) the sandwichlike intermediate is processed to the end product at a temperature of at least 90° C., a pressure of from 4 to 50 bar, and a pressing time of from 0.5 to 5 min.
摘要:
Mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates (raw MDI) having a reduced iodine color number and a reduced chlorine content are prepared by reacting the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylenepolyamines with phosgene in the presence of at least one inert organic solvent at elevated temperature, and then, after phosgenation is complete, incorporating into the reaction mixture, in the presence or absence of the phosgene, a mixture of water and at least one monohydric or polyhydric polyoxyalkylene alcohol, preferably having a functionality of from 2 to 3, and advantageously having a hydroxyl number of from 20 to 1800, in an effective amount which advantageously comprises from more than 0.01 to 0.3% by weight of water (i) and from 0.5 to 5% by weight of a polyoxyalkylene alcohol (ii), in each case based on the weight of raw MDI, then removing the excess phosgene or the phosgene residues still present and the inert organic solvent, if desired adding to the reaction product up to 5% by weight, based on the weight of raw MDI, of at least one antioxidant based on phenol and/or aryl phosphite and thermally treating the reaction mixture.
摘要:
In a process and an apparatus for preparing (cyclo)aliphatic polyisocyanates containing biuret groups from (cyclo)aliphatic diisocyanates and steam or a substance capable of splitting off water as reactants which are mixed with one another in a stirred reactor, the reactants are passes in countercurrent through a cascade-type stirred reactor comprising at least two stages. The dispersion of the gaseous reactant in the liquid reactant is reinforced by baffles installed in the stirred reactor. As baffles, use is made of discs provided with central openings and arranged at a distance from one another and/or strip baffles running in the longitudinal direction of the stirred reactor.
摘要:
A double-throw contact assembly, particularly for relay switches, or push button switches of the non-locking type, having a break contact, a make contact, and a pair of flexible contact arms associated therewith. Each contact arm is fixed adjacent one of its ends at a clamp point and has a free end movable into and out of contact with one of the break and make contacts. In their relaxed state, the arms converge at the clamp point from a bend intermediate the free end and the clamp point, thereby to define two linear portions or segments for each arm, a first straight segment for each arm extending from the clamp point to the bend, and a second straight segment for each arm extending from the bend to the free end of the arm.
摘要:
Water-absorbing, expanded, crosslinked polymers obtainable by (I) foaming a polymerizable aqueous mixture which comprises (a) monoethylenically unsaturated monomers which contain acidic groups and are optionally neutralized, (b) optionally other monoethylenically unsaturated monomers, (c) crosslinkers, (d) initiators, (e) 0.1-20% by weight of at least one surfactant, (f) optionally at least one solubilizer and (g) optionally thickeners, foam stabilizers, polymerization regulators, fillers and/or cell nucleating agents, where the foaming takes place by dissolving a gas which is inert to free radicals under a pressure of 2-400 bar in the polymerizable aqueous mixture, and then decompressing the latter to atmospheric pressure, and (II) polymerizing the foamed mixture to form an expanded hydrogel and, where appropriate, adjusting the water content of the expanded polymer to 1-60% by weight, process for preparing the water-absorbing, expanded, crosslinked polymers and use of these polymers in sanitary articles employed for absorbing body fluids, in dressing material for covering wounds, as sealing material, as soil improver, as soil substitute and as packaging material.
摘要:
A water-absorbing, expanded, crosslinked polymer obtainable by (I) foaming a polymerizable aqueous mixture which comprises (a) monoethylenically unsaturated monomers which contain acidic groups and are optionally neutralized, (b) optionally other monoethylenically unsaturated monomers, (c) crosslinkers, (d) initiators, (e) 0.1-20% by weight of at least one surfactant, (f) optionally at least one solubilizer and (g) optionally thickeners, foam stabilizers, polymerization regulators, fillers and/or cell nucleating agents, where the foaming takes place by dispersing fine bubbles of a gas which is inert to free radicals in the polymerizable aqueous mixture, and (II) polymerizing the foamed mixture to form an expanded hydrogel, whereby at least 20 mol % of the monomers (a) which contain acidic groups have been neutralized with tertiary alkanolamines and/or the free acidic groups of the expanded hydrogel have been at least 20 mol % neutralized with at least one alkalolamine after the polymerization, and, where appropriate, adjusting the water content of the expanded polymer to 1-60% by weight, the production thereof and the use thereof in hygiene articles employed to absorb body fluids and in dressing material for covering wounds.
摘要:
A process for reducing the foam formation when a dispersion or liquid is treated with steam by a) introduction of steam into the lower region of a column and simultaneous feed of a medium at the top of the column, the steam ascending to the top of the column, b) contacting the medium with the steam, with foam formation, includes the medium fed in stage a) having been generated by mixing a dispersion or liquid with steam in an apparatus, this medium during the feed into the top of the column having a higher temperature than that of the steam which comes into contact with the medium (in stage b)).
摘要:
Mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates (crude MDI) of reduced iodine color number are prepared by reacting the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylenepolyamines with phosgene in the presence of at least one inert organic solvent at elevated temperature, at least one monohydric or polyhydric polyoxyalkylene alcohol, preferably having a functionality of from 2 to 3, and advantageously having a hydroxyl number of from 20 to 1800, or mixtures thereof in an effective amount, expediently in an amount of from 0.1 to 10% by weight, based on the weight of the crude MDI, being introduced into the reaction mixture when the phosgenation is complete, the phosgene and the inert organic solvent then being removed, up to 5% by weight, based on the weight of crude MDI, of at least one phenol-based antioxidant and/or aryl phosphite being added, if desired to the reaction product, and the reaction mixture being heated.
摘要:
A process for the reduction of the residual monomer content and enhancement of the wet strength of articles formed from water absorbent crosslinked polymer foams containing units derived from monoethylenically unsaturated acids, which comprises treating the formed articles with at least 0.5% by weight of a polymer containing primary and/or secondary amino groups and having a molar mass of at least 300, the formed foam articles thus obtainable and use of the wet strength enhanced formed foam articles in hygiene articles.
摘要:
Mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates (crude MDI) having a reduced iodine color number are prepared by reacting the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylene-polyamines with phosgene in the presence of one or more inert organic solvents at elevated temperatures by a process in which low molecular weight alkanols, polyhydric alcohols, preferably dihydric to octahydric alcohols having a molecular weight of from 60 to 350, or mixtures thereof are incorporated in an effective amount, advantageously in an amount of from 0.01 to 5% by weight, based on the weight of crude MDI, into the reaction mixture after the end of the phosgenation, the phosgene and the inert organic solvent are then separated off, from 0 to 5% by weight, based on the weight of crude MDI, of one or more phenol-based antioxidants and/or aryl phosphite are added to the reaction product, and the reaction mixture is subjected to a thermal treatment.