CN1482924A - Hydrogels coated with steric or electrostatic spacers - Google Patents

Abstract

The invention relates to non-water soluble hydrogels which can swell in water, and which are coated with steric or electrostatic spacers. Before being coated, the hydrogels comprise the following characteristics: absorbency under load (AUL) (0.7 psi) of at least 20 g/g, and gel strength of at least 1600 Pa. The coated hydrogels preferably have the following characteristics: centrifuge retention capacity (CRC) of at least 24 g/g, saline flow conductivity (SFC) of at least 30 x 10<-7> cm<3> s/g, and free swell rate (FSR) of at least 0.15 g/g s and/or a maximum vortex time of 160 s.

Description

Hydrogel with steric hindrance or electrostatic spacers agent coating

The present invention relates to hydrogel, contain the water-absorbent compositions of this hydrogel, their production method, their purposes in hygienic articles and the method for the water-absorbent compositions that measure to be fit to.

Hygienic articles such as baby diaper or sanitary towel utilize very early can highly swollen hydrogel.This has significantly reduced the volume of hygienic articles.

The current trends of diaper design are developing than thin structure to the hydrogel content of cellulose fiber content with reduction and increase.Advantage itself than thin structure has not only shown improved use comfort, and packing and stock's cost reduces.Significantly changed the required performance profile of hydrophilic polymer of water-swellable to the trend of more and more thin diaper structure development.Decisive performance is the fluidic ability that hydrogel is dredged and distributed and drawn now.Relatively large polymer must not cause that swollen polymer forms follow-up fluidic barrier layer (gel blocking-up) on unit are in hygienic articles.The gel blocking-up can take place when the surface of fluid wets height water absorption hydrogel particle and epitheca swelling.The result has formed barrier layer, and this has reduced the liquid that is diffused into granule interior, has therefore caused spilling.Good gel permeation and therefore good transportation performance guaranteed the optimum utilization of whole hygienic articles.

Regulate the degree of cross linking of starting polymer and afterwards crosslinked subsequently reaching the optimization of water absorption and gel strength by target, thereby realized the purpose of higher dosage that can highly swollen hydrogel.Improved gel permeation value can be only by producing than high crosslink density in the starting polymer.Yet the higher crosslink density and the absorbability of reduction and the reduction of polymers swell rate are closely connected together.The result is that the increase of the hydrogel content of hygienic articles makes that must introduce extra play prevents to spill, this so that caused hygienic articles bulky and run in the opposite direction with the actual purpose of producing than approaching health care products.

It is to make particle size range become higher value that the feasible method that improves transportation performance and avoid gel to block is provided.Yet this causes swelling ratio to descend, because the surface area of water absorbing material reduces.This is undesirable.

The another way that obtains the improvement gel permeation is that the back, surface is crosslinked, and this water gel of giving solvent swelling state is with higher gel strength.The gel of undercapacity is at pressure, for example can be out of shape under the pressure that is brought by the body weight of the user of hygienic articles, so stopped up hole in hydrogel/cellulose fibre absorbent, therefore hindered fluidic continuous absorption.For above reason be impossible because increase the crosslink density of starting polymer, so the back, surface crosslinked be the excellent way that increases gel strength.Crosslink density in the crosslinked shell that increases hydrogel particle in back, surface, the load absorption (AUL) of the base polymer that the result produces like this rises to higher level.Though the absorbability of hydrogel shell descends, the core of hydrogel particle has improved absorbability (comparing with shell), and this is owing to there is the flowing copolymer chain, makes shell mechanism guarantee improved fluid breathability.

Yet, the phenomenon that can highly swollen hydrogel still produce the gel blocking-up of high consumption.Therefore, major criterion must be to dredge fluidic ability in solvent swelling state.Have only good fluid to dredge just to guarantee utilize fully can highly swollen hydrogel real advantage, promptly they absorb and reserve capability for aqueous body fluids is significant.Yet importantly, fluid is dredged in the intended performance of hygienic articles and is occurred.The complete absorbability of hydrogel should be utilized in this process.Hydrogel is dredged fluidic ability and is quantized according to saline flow conductivity (SFC).SFC has weighed formed hydrogel layer and dredged fluidic ability under set pressure.It is believed that under high consumption, hydrogel particle contacts with each other under solvent swelling state, form the continuous absorption layer, in this absorbed layer, carry out fluid and distribute.

The follow-up modification on the surface of base polymer (the crosslinked starting polymer in back, surface) is known.

DE-A-3 523 617 relate to carry out with carboxyl-reactive cross-linking agent material surface back crosslinked after, the powdery amorphous silica is joined in the dried hydrogel powder.

In the prior art, aluminum sulfate is used as unique cross-linking agent in crosslinked or combines with other cross-linking agent behind the surface.

WO95/22356 relate to absorbable polymer with other polymer modification to improve the method for absorbent properties.Preferred modifiers is polyamines and many imines.Yet,, be minimum for the effect of SFC according to table 1 and 2.

WO95/26209 relates to and has the absorbing structure that at least one contains the zone of 60-100% height swellability hydrogel, and this hydrogel has at least 30 * 10 ^-7Cm ³The SFC of s/g and the PUP 0.7psi of 23g/g at least.Wherein illustration this can highly swollen hydrogel can be by crosslinked acquisition the behind the surface.From table 1 and 2 as can be seen, it can be the SFC that cost provides increase to reduce the gel volume only that this class is handled, and promptly has reciprocal relationship between retention property and gel permeation.

SFC increases with the increase of granularity that can highly swollen hydrogel.When granularity increases, surface area and the proportional reduction of their volume that can highly swollen hydrogel particle, this has caused the swelling ratio that lowers.Therefore can infer that swelling ratio also has reciprocal dependency to SFC from these result of experiment.

The purpose of this invention is to provide when using in hygienic articles, that has both good transportation performance and high osmosis and high limit absorbability and high swelling ratio can highly swollen hydrogel or water-absorbent compositions.In the prior art, the high absorbent capacity of hydrogel, high liquid transport performance and fast swellability be mutually exclusive, and opposite with prior art, produced novel can highly swollen hydrogel should be in conjunction with opposite parameter.In addition, can produce thin hygienic articles by highly swollen hydrogel with high consumption according to of the present invention.For this reason, should form show high swelling ratio or absorbance, high gel permeation and high retention simultaneously can highly swollen hydrogel.If exist excellent fluid to distribute, the high total capacity that the present invention in absorbed layer can highly swollen hydrogel should be utilized best.

We have found that the hydrogel of this purpose water-insoluble water-swellable by scribbling steric hindrance or electrostatic spacers agent according to the present invention realizes, be characterised in that to have feature before the following coating:

-at least the load absorption of 20g/g (AUL) (0.7psi),

-the gel strength of 1600Pa at least.

Hydrogel after the coating preferably has following feature in addition:

-centrifugal the reserve capacity (CRC) of 24g/g at least,

-at least 30 * 10 ^-7, preferably at least 60 * 10 ^-7Cm ³The saline flow conductivity (SFC) of s/g and

-at least 0.15g/g free swell rate (FSR) and/or be no more than the vortex time of 160s.

Term " water absorption " relates to water and can contain the Aquo System of the organic or inorganic chemical compound of dissolved state, especially body fluid such as urine, blood or contain their fluid.

Other goods that hydrogel of the present invention and the water-absorbent compositions that contains them can be used for producing hygienic articles or absorb aqueous fluid.Therefore the present invention further relates to the hygienic articles that contains water-absorbent compositions of the present invention between permeable top sheet of liquid and liquid impermeability tergite.This hygienic articles can exist with diaper, sanitary towel and the incontinence form with product.

The present invention also provides the hydrogel by the water-insoluble water-swellable of use as above definition to strengthen the capacity of permeability, water-absorbent compositions and the method for the performance profile that swelling ratio improves water-absorbent compositions.

The present invention further provides the method for measuring water-absorbent compositions with high osmosis, capacity and swelling ratio, centrifugal reserve capacity (CRC), saline flow conductivity (SFC) and the free swell rate (FSR) of the hydrogel after comprising the load absorption (AUL) and the gel strength of the uncoated hydrogel of measuring set water-absorbent compositions and measuring coating, and measure the water-absorbent compositions that its hydrogel shows above-mentioned performance range.

The present invention further provides hydrogel as above definition in hygienic articles or other goods, be used to absorb aqueous fluid with strengthen permeability, capacity and swelling ratio purposes.

Be surprisingly found out that, use has 20g/g, preferred 22g/g at least, especially preferred 24g/g at least, the more specifically preferred AUL of 26g/g (0.7psi) at least at least, at least 1600Pa, preferred 1800Pa at least, the especially preferred base polymer of the gel strength of 2000Pa at least, be coated with steric hindrance (inertia) or electrostatic spacers agent subsequently in its surface, reached above purpose fully.Base polymer with these performances has guaranteed that this interval dose effect is not offset by excessively easy gel particle morphotropism under restraining forces.

The technology of adding steric hindrance or electrostatic spacers agent makes might produce the hygienic articles that has the high-load hydrogel in absorbed layer.In addition, the hydrogel with electrostatic spacers agent also has the improvement adhesion to cellulose fibre, because the latter has weak negative charge from the teeth outwards.This fact is especially favourable, because this can make hydrogel and electrostatic spacers agent and the cellulose fibre generation absorbed layer with described performance profile, and does not need extra auxiliary agent that hydrogel is fixed in the fibre substrate.Automatically realize the fixing of hydrogel material with combining of cellulose fibre, made hydrogel material can heavily be distributed in for example surface of absorbent cores ideally.

Of the present invention can being celebrated because of high absorptive capacity, improved liquid transportation performance and higher swelling ratio by highly swollen polymer beads.Therefore, can make as thin as a wafer hygienic articles.Increase consumption high power capacity of the present invention can provide huge absorbent properties by highly swollen hydrogel, make that spilling problem is also avoided.Simultaneously, improved liquid-distribution property has guaranteed that high absorbent capacity is utilized fully.

The present invention relates to novel production method that can highly swollen hydrogel, comprising:

(1) select in advance to have 20g/g, preferred 22g/g at least at least, especially preferred 24g/g at least, the more specifically preferred AUL of 26g/g (0.7psi) at least and at least 1600Pa, preferred 1800Pa at least, especially preferably at least the gel strength of 2000Pa can highly swollen base polymer

(2) with steric hindrance or electrostatic spacers agent post processing (coating) is carried out on the surface according to the base polymer of above Standard Selection.

Being coated with that these preselected hydrogels provide can highly swollen hydrogel, and opposite with prior art, it has both high swelling ratio or absorbance and high gel permeation and high retention.

Therefore this obtained to have the hydrogel of following performance combination:

-CRC is not less than 24g/g, preferably is not less than 26g/g, more preferably is not less than 28g/g, also more preferably is not less than 30g/g, especially preferred CRC be not less than 32g/g and most preferably CRC be not less than 35g/g

With

-SFC is not less than 30 * 10 ^-7Cm ³S/g preferably is not less than 60 * 10 ^-7Cm ³S/g preferably is not less than 80 * 10 ^-7Cm ³S/g more preferably is not less than 100 * 10 ^-7Cm ³S/g also more preferably is not less than 120 * 10 ^-7Cm ³S/g especially preferably is not less than 150 * 10 ^-7Cm ³S/g also especially preferably is not less than 200 * 10 ^-7Cm ³S/g most preferably is not less than 300 * 10 ^-7Cm ³S/g,

With

-free swell rate is not less than 0.15g/gs, preferably is not less than 0.20g/gs, more preferably is not less than 0.30g/gs, also more preferably is not less than 0.50g/gs, especially preferably is not less than 0.70g/gs, most preferably is not less than 1.00g/gs

Or

Vortex time is no more than 160s, and preferred vortex time is no more than 120s, and more preferably vortex time is no more than 90s, and especially preferred vortex time is no more than 60s, and most preferably vortex time is no more than 30s.Hydrogel with water-swellable of interval dose

Be used to form the polymer of hydrophilic monomer of the especially polymerization of polymer (copolymerization) of hydrogel, the graft polymers (copolymer) of one or more hydrophilic monomers on suitable grafting matrix, cross-linked cellulose or starch ethers, cross-linked carboxymethyl cellulose, partial cross-linked polyoxyalkylene, or in aqueous fluid the natural product of swellable, for example guar derivative, alginate and carrageenin.

The grafting matrix that is fit to can be natural or synthetic source.Example is starch, cellulose or cellulose derivative and other polysaccharide and oligosaccharide, polyvinyl alcohol, polyoxyalkylene, especially poly(ethylene oxide) and poly(propylene oxide), polyamines class, polyamide-based and hydrophilic polyesters class.The polyoxyalkylene that is fit to for example has following structural formula:

Wherein

R ¹And R ²Be hydrogen, alkyl, alkenyl or aryl independently,

X be hydrogen or methyl and

N is the integer of 1-10000.

R ¹And R ²Preferably hydrogen, (C separately ₁-C ₄)-alkyl, (C ₂-C ₆)-alkenyl or phenyl.

The preferred polymer that forms hydrogel is the cross linked polymer with acidic group, and they mainly exist with their salt, the form of general alkali metal salts or ammonium salt.These polymer swelling especially consumingly when contacting hydrous fluid forms gel.

Preferably belong to the cross-linked polymeric of unsaturated monomer or its salt or the polymer that copolymerization obtains by acid-functionalized monoene.Might come these monomers of polymerization (copolymerization) and crosslinked subsequently without cross-linking agent in addition.

These monomeric examples that carry acid groups are that monoene belongs to unsaturated C ₃-C ₂₅Carboxylic acid or anhydride or anhydride, as acrylic acid, methacrylic acid, ethylacrylic acid, α-Lv Bingxisuan .beta.-methylacrylic acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, mesaconic acid, glutaconate, equisetic acid and fumaric acid.Also might use monoene to belong to unsaturated sulfonic acid or phosphonic acids, vinyl sulfonic acid for example, allyl sulphonic acid, acrylic acid sulphur ethyl ester, methacrylic acid sulfo group ethyl ester, acrylic acid sulfo group propyl ester, methacrylic acid sulfo group propyl ester, 2-hydroxyl-3-acryloxy propyl sulfonic acid, 2-hydroxy-3-methyl acryloxy propyl sulfonic acid, vinyl phosphonate, pi-allyl phosphonic acids, styrene sulfonic acid and 2-acrylamido-2-methyl propane sulfonic acid.Monomer can be used alone or as a mixture.

Preferred monomer is an acrylic acid, methacrylic acid, vinyl sulfonic acid, acrylamido propane sulfonic acid or their mixture, the for example mixture of acrylic acid and methacrylic acid, the mixture of acrylic acid and acrylamido propane sulfonic acid or the mixture of acrylic acid and vinyl sulfonic acid.

In order to optimize performance, can suitably use do not carry acidic group but can with other monoene ethylenically unsaturated compounds of the monomer copolymerization that carries acidic group.These chemical compounds comprise for example amide and the nitrile of monoethylenically unsaturated carboxylic acid, acrylamide for example, Methacrylamide and N-vinyl formamide, N-vinyl acetamide, N-methyl-N-vinyl acetamide, acrylonitrile and methacrylonitrile.Other examples for compounds that is fit to is saturated C ₁-C ₄The vinyl acetate of carboxylic acid such as vinyl formate, vinyl acetate or propionate; The alkyl vinyl ether that in alkyl, has at least 2 carbon atoms, for example ethyl vinyl ether or butyl vinyl ether; Monoene belongs to unsaturated C ₃-C ₆The ester of carboxylic acid, for example monobasic C ₁-C ₁₈The ester of alcohol and acrylic acid, methacrylic acid or maleic acid, the monoesters of maleic acid, maleic acid hydrogenation methyl ester for example, N-vinyl lactam such as N-vinyl pyrrolidone or N-caprolactam; The acrylate and the methacrylate of alkoxylate monobasic saturated alcohols, described alcohol for example is to react and have the alcohol of 10-25 carbon atom with 2-200mol oxirane and/or expoxy propane/mol alcohol, and the mono acrylic ester of Polyethylene Glycol or polypropylene glycol and monomethacrylates, the molal weight of poly alkylene glycol (Mn) for example is at most 2000.Other monomer that is fit to is the styrene that styrene and alkyl replace, as ethyl styrene or t-butyl styrene.

There are not these monomers of acidic group can also mix use, for example the mixture of the arbitrary proportion of vinyl acetate and acrylic acid-2-hydroxyl ethyl ester with other monomer.There are not these monomers of acidic group to join in the reactant mixture with the amount that at 0-50 weight %, preferably is lower than in the 20 weight % scopes.

Preferably carry acidic group and the optional monoene that is converted into alkali metal salts or ammonium salt belongs to unsaturated monomer and 0-40 weight % (based on their gross weight) before or after polymerization the monoene that does not carry acidic group belong to unsaturated monomer cross linked polymer.

Preferably monoene belongs to unsaturated C ₃-C ₁₂The cross linked polymer of carboxylic acid and/or their alkali metal salts or ammonium salt.Especially preferred cross linked polyacrylate, the 25-100% of its acidic group exists as alkali metal salts or ammonium salt.

Possible cross-linking agent comprises the chemical compound that contains at least two ethylenical unsaturated double bonds.The example of this compounds is N, N '-methylene-bisacrylamide, each freely has 106-8500, preferred 400-2000 molecular weight polyethylene glycol is derived and next polyethyleneglycol diacrylate and polyethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylol-propane trimethacrylate, glycol diacrylate, ethylene glycol dimethacrylate, propylene glycol diacrylate, the propylene glycol dimethylacrylate, butanediol diacrylate, butanediol dimethylacrylate, hexanediyl ester, hexanediol dimethacrylate, allyl methacrylate, the diacrylate of the block copolymer of oxirane and expoxy propane and dimethylacrylate, polyhydric alcohol such as glycerol or tetramethylolmethane with acrylic or methacrylic acid diesterization or higher esterization, triallylamine, dialkyl monohalide diallyl ammonium such as chlorination dimethyldiallylammonium and chlorination diethyl diallyl ammonium, the tetraallyl ethylene diamine, divinylbenzene, diallyl phthalate, Polyethylene Glycol divinyl ether with 106-4000 molecular weight polyethylene glycol, trimethylolpropane allyl ether, the butanediol divinyl ether, pentaerythritol triallyl ether, the pentaerythritol triallyl ether of the Ethylene glycol diglycidyl ether of 1mol or polyethyleneglycol diglycidylether and 2mol or the product of allyl alcohol, and/or divinyl ethylidene-urea.The preferred water-soluble cross-linker that uses, N for example, N '-methylene-bisacrylamide, the polyethyleneglycol diacrylate and the polyethylene glycol dimethacrylate that obtain by the addition compound product of the glycol of the oxirane of 2-400mol and 1mol or polyhydric alcohol, the vinyl ethers of the addition compound product of the oxirane of 2-400mol and the glycol of 1mol or polyhydric alcohol, glycol diacrylate, ethylene glycol dimethacrylate, or the triacrylate and the trimethyl acrylic ester of the addition compound product of 6-20mol oxirane and 1mol glycerol, pentaerythritol triallyl ether and/or divinyl urea.

Possible cross-linking agent also comprises the chemical compound that contains at least one polymerisable ethylenically unsaturated group and at least one other functional group.The functional group of these cross-linking agent must with monomeric functional group, acid-base reaction especially.The functional group that is fit to for example comprises hydroxyl, amino, epoxy radicals and '-aziridino.Useful for example is the hydroxy alkyl ester of above-mentioned monoethylenically unsaturated carboxylic acid, acrylic acid 2-hydroxyl ethyl ester for example, Hydroxypropyl acrylate, the acrylic acid hydroxy butyl ester, hydroxyethyl methylacrylate, Hydroxypropyl methacrylate, with the methacrylic acid hydroxy butyl ester, bromination pi-allyl piperidines, N-vinyl imidazole class, N-vinyl imidazole for example, 1-vinyl-glyoxal ethyline and N-vinyl imidazole quinoline class such as N-vinyl imidazole quinoline, 1-vinyl-glyoxal ethyline quinoline, 1-vinyl-2-ethyl imidazol(e) quinoline or 1-vinyl-2-propyl imidazole quinoline, they can be with the form of free alkali, with season form or in polymerization, use as salt.Can also use propenoic acid dialkyl aminoalkyl ester and methacrylic acid dialkyl aminoalkyl ester, as the acrylic acid dimethylamino ethyl ester, dimethylaminoethyl methacrylate, acrylic acid diethylamino ethyl ester and diethyl aminoethyl methacrylate.Alkaline ester is preferably with season form or use as salt.For example, can also use (methyl) glycidyl acrylate.

Useful cross-linking agent further comprise contain can with the chemical compound of at least two functional groups of monomeric functional group, main and acid-base reaction.The functional group that is fit to mentions in the above, i.e. hydroxyl, amino, epoxy radicals, isocyanates, ester, amide groups and '-aziridino group.The example of these cross-linking agent is an ethylene glycol, diethylene glycol, 2,2'-ethylenedioxybis(ethanol)., tetraethylene glycol (TEG), Polyethylene Glycol, glycerol, polyglycereol, triethanolamine, propylene glycol, polypropylene glycol, the block copolymer of oxirane and expoxy propane, ethanolamine, fatty acid esters of sorbitan, ethoxylation dehydrated Span, trimethylolpropane, tetramethylolmethane, 1,3 butylene glycol, 1, the 4-butanediol, polyvinyl alcohol, sorbitol, starch; Many glycidyls ethers, as the ethylene glycol bisthioglycolate glycidyl ether, the Polyethylene Glycol diglycidyl ether, the glycerol diglycidyl ether, the many glycidyl ethers of glycerol, the many glycidyl ethers of diglycerol, the polyglycereol polyglycidyl ether, the sorbitol polyglycidyl ether, tetramethylolmethane polyglycidyl ether, propylene glycol diglycidylether and polypropylene glycol diglycidyl ether; The polyaziridine chemical compound is as 2, the two methylol butanols three [3-(1-'-aziridino) propionic ester] of 2-, and 1,6-hexa-methylene diethylidene urea, diphenyl methane is two-4,4 '-N, N '-diethylidene urea; The halogenated epoxy based compound is as chloropropylene oxide and Alpha-Methyl-epichlorhydrin; Polyisocyanates is as 2,4 toluene diisocyanate and hexamethylene diisocyanate; Alkylene carbonates, as 1,3-dioxolanes-2-ketone and 4-methyl isophthalic acid, 3-dioxolanes-2-ketone; And bisoxazoline is with oxazolidone; The product of polyamide-based amine and they and chloropropylene oxide; And poly-season amine, as the condensation product of dimethyl amine and chloropropylene oxide, the homopolymer of chlorination diallyl dimethyl ammonium and copolymer, and optional with for example homopolymer and the copolymer of (methyl) acrylic acid dimethylamino ethyl ester of methyl chloride seasonization.

Cross-linking agent for example is present in the reactant mixture with 0.001-20 weight %, preferred 0.01-14 weight %.

Polymerization causes by initiator with usual way.But polymerization can also be used for causing to polymerisable aqueous mixture by electron beam.Yet polymerization can also cause by the high-energy radiation in the presence of light trigger under the situation of above-mentioned initiator not having.Useful polymerization initiator is included in all chemical compounds that resolve into free radical under the polymerizing condition, for example peroxide, hydroperoxides, hydroperoxide kind, persulfate, azo-compound and oxidation reduction catalyst.The use of water soluble starter is preferred.In some cases, advantageously use the mixture of different polymerization initiators, for example, the mixture of hydrogen peroxide and sodium persulfate or potassium persulfate.The mixture of hydrogen peroxide and sodium persulfate can use with any ratio.The example of the organic peroxide that is fit to is an acetyl acetone peroxide, methyl-ethyl-ketone peroxide, tert-butyl hydroperoxide; cumene hydroperoxide; cross the neopentanoic acid tert-pentyl ester, cross the neopentanoic acid tert-butyl ester, cross new hecanoic acid t-butyl ester; t-butyl peroxy-isobutylate; cross-the 2 ethyl hexanoic acid tert-butyl ester, cross the different n-nonanoic acid tert-butyl ester, tert butyl permaleic acid; t-butyl perbenzoate; cross two carbonic acid two (2-ethylhexyl) ester, cross two carbonic acid, two cyclohexyls, cross two carbonic acid two (4-tert-butylcyclohexyl) ester; cross two carbonic acid myristyl esters; cross two carbonic acid diacetyl esters, pi-allyl is crossed esters, crosses neodecanoic acid cumyl ester; cross-3; 5, the 5-tri-methyl hexanoic acid tert-butyl ester, acetyl group cyclohexyl sulfonyl-peroxide; dilauryl peroxide, dibenzoyl peroxide and mistake neodecanoic acid tert-pentyl ester.Particularly suitable polymerization initiator is a water-soluble azo initiator; for example; 2, two (2-amidine propane) dihydrochlorides of 2 '-azo, 2; 2 '-azo is two-(N; N '-dimethylene) 2,2-Dimethylaziridine dihydrochloride, 2-(carbamoyl azo) isopropyl cyanide, 2; two [2-(2 '-imidazoline-2-yl) propane] dihydrochlorides and 4 of 2 '-azo, 4 '-azo two (4-cyanopentanoic acid).Described polymerization initiator for example uses with the amount of 0.01-5 weight %, preferred 0.05-2.0 weight % with usual amounts, based on the polymeric monomer of want.

Useful initiator also comprises oxidation reduction catalyst.In oxidation reduction catalyst, oxidation component is at least a of above-mentioned per-compound, reduction components for example is ascorbic acid, glucose, sorbose, ammonium or alkali metal bisulfites, sulphite, thiosulfate, dithionate, pyrosulfate or sulfide, or slaine, as ferrum (II) ion or methylol sodium hydrosulfide.Reduction components in oxidation reduction catalyst is ascorbic acid or sodium sulfite preferably.For example, can use 3 * 10 ^-6To the oxidation component of the oxidation reduction catalyst of the reduction components of the redox (-)catalyst system of 1mol% and 0.001-5.0mol%, based on the amount of monomer of in polymerization, using.

When polymerization used high-energy radiation to cause, employed initiator is light trigger normally.Light trigger for example comprises α-distintegrant, and H-captures system or azide.The example of these initiators is benzophenone derivates such as Michler's keton; phenanthrene derivative; fluorene derivative; anthraquinone derivative; thioxanthone derivates, coumarin derivative, benzoin ethers and their derivant; azo-compound such as above-mentioned free radical form agent, replace hexa-aryl bi-imidazole class or acylphosphine oxide class.The example of azide is: 4-azido cinnamic acid 2-(N; the N-dimethylamino) ethyl ester; 2-(N; the N-dimethylamino) ethyl 4-azido naphthyl ketone; 4-triazobenzene formic acid 2-(N, N-dimethylamino) ethyl ester, 5-azido-1-naphthyl 2 '-(N; the N-dimethylamino) ethyl sulfone; N-(4-sulfonyl azido-phenyl) maleimide, N-acetyl group-4-sulfonyl azido aniline, 4-sulfonyl azido aniline; 4-azido aniline; 4-azido phenacyl bromide is to triazobenzene formic acid, 2; two (to the azido benzal base) Ketohexamethylene and 2 of 6-, two (to azido benzal the base)-4-methyl-cyclohexyl ketone of 6-.If use, the consumption of light trigger is the 0.01-5% of the polymeric monomer weight of wanting normally.

Follow-up cross-linking stage comprises that belonging to unsaturated acids and optional monoene by above-mentioned monoene belongs to the polymerization preparation of unsaturated comonomer and have the polymer and the chemical compound reaction that has at least two groups of responding property of acidic group that surpasses 5000, preferably surpasses 50000 molecular weight.This reaction can be at room temperature or is being carried out under 220 ℃ the high temperature at the most.

The functional group that is fit to mentions in the above, i.e. hydroxyl, amino, epoxy radicals, isocyanates, ester, amide groups and '-aziridino group, and the example of these cross-linking agent.Cross-linking agent joins in acid-functionalized polymer or the salt with the amount of 0.5-25 weight %, preferred 1-15 weight %, based on the consumption of polymer.

Cross linked polymer preferably uses with complete neutral form.Yet neutralization can also only be partly.Degree of neutralization is preferably in the scope of 25-100%, especially in the scope of 50-100%.Useful nertralizer comprises alkali metal base or ammonia/amine.Preferred sodium hydrate aqueous solution or the potassium hydroxide aqueous solution of using.Yet neutralization can also use sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate or other carbonate or bicarbonate or ammonia to carry out.And can use primary, the second month in a season and tertiary amines.

The commercial run that is used to prepare these products comprises all methods that are generally used for preparing superabsorbents, as the 3rd chapter at " Modern Superabsorbent Polymer Technology ", F.L.Buchholz and A.T.Graham, Wiley-VCH is described in 1998.

Polymerization in aqueous solution is preferably carried out as gel polymerisation.It comprises that the monomer and the 10-70 weight % aqueous solution of the suitable grafting matrix of choosing wantonly utilize Trommsdorf-Norish effect to come polymerization in the presence of radical initiator.

Polyreaction can 0-150 ℃, preferably under 0-100 ℃, not only can be, and can under super-atmospheric pressure or decompression, carry out at atmospheric pressure.Usually, polymerization can also for example be carried out under nitrogen in the protective gas atmosphere.

By subsequently under 50-130 ℃, preferably 70-100 ℃ of following heated polymerizable thing gel several hours, the polymer properties characteristic can further be modified.

Preferably carried out the polymer of the crosslinked formation hydrogel in back, surface.The crosslinked polymer beads that can use drying, grinding in normal way and classify in back, surface carries out.

Crosslinked in order to finish surface back, the chemical compound of functional group reactions that can be by crosslinked and polymer is applied on the surface of hydrogel particle, and preferably the form with aqueous solution applies.This aqueous solution can contain the water miscibility organic solvent.The solvent that is fit to is an alcohols, as methanol, ethanol, isopropyl alcohol or acetone.

Back, the surface cross-linking agent that is fit to for example comprises:

-two or multi-shrinking glyceryl compound, as diglycidyl phosphonate ester or Ethylene glycol diglycidyl ether, two chloropharin ethers of poly alkylene glycol,

-polyglycidyl compounds, the polyaziridine class, based on polyethers or replace the aziridine cpd of hydro carbons, for example pair-N-'-aziridino methane,

-polyalcohols, as ethylene glycol, 1, the 2-propylene glycol, 1, the 4-butanediol, glycerol, the methyl 2,2'-ethylenedioxybis(ethanol)., the Polyethylene Glycol with 200-10000 average molecular weight Mw, two glycerol and polyglycereol, tetramethylolmethane, sorbitol, ester such as the ethylene carbonate or the propylene carbonate of the ethoxylate of these polyhydric alcohol and they and carboxylic acid or carbonic acid

-carbonic acid derivative, as urea, thiourea, guanidine, dicyandiamide, the derivant ， bisoxazoline ， Ju oxazoline class of 2-oxazolidone and it, two and polyisocyanates,

-two-and many-N-methylol compound, for example di-2-ethylhexylphosphine oxide (N-methylol methacrylamide) or melamine-formaldehyde resin,

-have the chemical compound of two or more blocked isocyanate bases, for example use 2,2,3, the trimethyl hexamethylene diisocyanate of 6-tetramethyl piperidine-4-ketone sealing.

If necessary, can add acidic catalyst, for example p-methyl benzenesulfonic acid, phosphoric acid, boric acid or Ammonium biphosphate.

Especially back, the surface cross-linking agent that is fit to is two-or multi-shrinking glyceryl compound, as Ethylene glycol diglycidyl ether, the product of polyamide-based amine and chloropropylene oxide and 2-oxazolidone.

Cross-linking agent solution is preferably sprayed and is applied by being used in cross-linking agent solution among common response mixer or mixing and drying equipment such as Patterson-Kelly mixer, DRAIS turbulent flow mixer, L dige mixer, screw mixer, board-like mixer, fluid bed mixer and the Schugi Mix.Is heat treatment step after the spraying of cross-linking agent solution, preferably in downstream dryer, 80-230 ℃, preferred 80-190 ℃, especially preferably under 100-160 ℃, carried out 5 minutes to 6 hours, preferred 10 minutes to 2 hours, especially preferred 10 minutes to 1 hour; During this period, not only pyrolysis product can be removed, the solvent fraction can also be removed.But drying can also be carried out by heating jacket or by being blown into the preheating carrier gas in mixer itself.The steric hindrance interval dose

Useful steric hindrance interval dose comprises inert material (powder), for example has the silicate (Montmorillonitum, Kaolin, Talcum) of band shape, chain or laminated structure, zeolite, active carbon or silicon dioxide.Inorganic inertia interval dose further comprises for example magnesium carbonate, calcium carbonate, barium sulfate, aluminium oxide, titanium dioxide, and ferrous oxide (II).Organic inertia interval dose comprises for example polyalkyl methacrylate or thermoplastic such as polrvinyl chloride.The preferred silicon dioxide that uses, they are divided into precipitated silica and pyrogenic silica according to its preparation method.Two kinds of modification can be purchased under trade name AEROSIL  (pyrogenic silica) or Silica FK, Sipernat , Wessalon  (precipitated silica).Siloxanes and silanol are carried in the surface of silica dioxide granule.Has more siloxane group.They are reason places of the basic inert nature of this synthetic silica.The particular type of silicon dioxide can be used for different application.For example, can add silane and come silica surface is carried out chemical modification, make initial hydrophilic silicon dioxide be converted into hydrophobic type.Some silicon dioxide grades can be used as mixed oxide for example with the blend utilization of aluminium oxide.The function of interval dose can constitute according to the surface of primary granule to be controlled.Pyrogenic silica (for example AERSIL ) obtains with the granularity grades of 7-40nm.Silicon dioxide under trade name Silica FK, Sipernat  and Wessalon  can be used as granularity grades and the 50-450m of 5-100 μ m ²The powder of the specific surface area of/g obtains.

In order to be used as the steric hindrance interval dose, the granularity of inert powder is at least 1 μ m preferably, more preferably at least 4 μ m, especially preferably at least 20 μ m, more preferably at least 50 μ m.The use of precipitated silica is particularly preferred.

The processing of inertia silicon dioxide grade generally is safe on physiology.This allows to use without reservation this class material in hygienic articles.

Base polymer with the coating of inertia interval dose material can be produced by being applied on the powdery base polymeric material at the inertia interval dose in moisture or the water miscibility medium or by the inertia interval dose with powder type.Aqueous or water miscibility medium preferably applies by being sprayed on the dry polymer powder.In the particularly preferred modification of this production method, prepare pure powder/powder blend by powdery inertia interval dose material and base polymer.Inertia interval dose material is applied on the surface of base polymer with the ratio of 0.05-5 weight %, preferred 0.1-1.5 weight %, especially preferred 0.3-1 weight %, based on the gross weight of the hydrogel after the coating.The electrostatic spacers agent

Cationic components can be used as the electrostatic spacers agent to be added.

Generally can add cationic polymer and be used for Coulomb repulsion.This for example realizes with following material: the polyethyleneimine: amine, the polyvinyl amine, polyamines class such as polyalkylenepolyamines class, the cationic derivative of polyacrylamide, the polyethyleneimine: amine, poly-quaternary ammonium, for example, hexamethylene diamine, the condensation product of dimethyl amine and chloropropylene oxide, the condensation product of dimethyl amine and chloropropylene oxide, the copolymer of hydroxyethyl-cellulose and chlorination diallyl dimethyl ammonium, the copolymer of acrylamide and chlorination Beta-methyl acryloxy-ethyl trimethyl ammonium, with chloropropylene oxide reaction and the hydroxylated cellulose of using Trimethylamine seasonization then, the addition compound product of the homopolymer of chlorination diallyl dimethyl ammonium or chloropropylene oxide and amide groups amine.Poly-quaternary amine can further synthesize by the reaction of dimethyl sulfate and polymer, described polymer is the polyethyleneimine: amine for example, the copolymer of the copolymer of vinyl pyrrolidone and dimethylaminoethyl methacrylate or ethyl methacrylate and diethyl aminoethyl methacrylate.Poly-quaternary amine can the wide molecular weight scope obtain.

The electrostatic spacers agent is also by applying crosslinked cation epitheca with the reagent (for example addition compound product of chloropropylene oxide and polyamide-based amine) that can self form network, or can produce with the cationic polymer of the cross-linking agent reaction of adding by applying, the cross-linking agent of interpolation for example is the conjugate of polyamines or many imines and polyepoxide, multifunctional ester, polyfunctional acid or multifunctional (methyl) acrylate.Can also use to have uncle or any polyfunctional amine of secondary amino group polymine for example, PAH, polylysine, preferably polyethylene base amine.Other example of polyamines is an ethylenediamine, diethylenetriamines, and trien, tetren, penten and polymine also have molal weight in all cases up to 4 000 000 polyamine.

The electrostatic spacers agent can also by add bivalence or more the solution of high-valency metal salt apply.Bivalence or more the example of high valent cationic be Mg ²⁺, Ca ²⁺, Al ³⁺, Sc ³⁺, Ti ⁴⁺, Mn ²⁺, Fe ^2+/3+, Co ²⁺, Ni ²⁺, Cu ^+/2+, Zn ²⁺, Y ³⁺, Zr ⁴⁺, Ag ⁺, La ³⁺, Ce ⁴⁺, Hf ⁴⁺And Au ^+/3+, preferred metal cation is Mg ²⁺, Ca ²⁺, Al ³⁺, Ti ⁴⁺, Zr ⁴⁺And La ³⁺, and particularly preferred metal cation is Al ³⁺, Ti ⁴⁺And Zr ⁴⁺Metal cation not only can use separately, and can intermingling.In the middle of mentioned metal cation, all salt that have abundant dissolubility in solvent for use are fit to.Suitable especially is to have for example slaine of chloride ion, nitrate anion and sulfate radical of Weakly coordinating anions.The useful solvent of slaine comprises water, alcohol, DMF, DMSO and their mixture.Particularly preferably be water and water-alcohol mixture, for example water/methanol, or water/1,2-propylene glycol.

In production method, the electrostatic spacers agent can be as the inertia interval dose by applying in moisture or water miscibility medium.This is a preferred production methods under the situation of adding slaine.Cationic polymer is with aqueous solution, or the solution in water-miscible solvent, and is also optional as dispersion, or is applied on the powdery base polymeric material with the powder form.Moisture or water miscibility medium preferably applies by being sprayed on the dry polymer powder.Subsequently can the optionally drying polymer powders, in this case, the base polymer of coating can only be no more than under 100 ℃ the temperature dry.Higher temperature will cause forming covalent bond between polyamine component and polycarboxylate, and this under any circumstance all should be avoided, so that the additive-crosslinking that the result brings can exceedingly not reduce the capacity of product.For this reason, when being coated with, preferably do not comprise this heat treatment step with polyamines.When using the additive-crosslinking agent, select heat-treat condition, make that only the polyamines coating is crosslinked, and following polycarboxylate is not crosslinked.

The cation interval dose is applied on the surface of base polymer with the ratio of 0.05-5 weight %, preferred 0.1-1.5 weight %, especially preferred 0.1-1 weight %, based on the gross weight of the hydrogel that is coated with.

Described hydrogel is celebrated to the high-absorbable of water and aqueous solution with it, and is therefore first-selected as the absorbent in the hygienic articles.

The hydrogel of water-swellable can exist with sheathing material jointly with hydrogel, preferably be embedded in polymer fiber substrate or the open cell polymer foams, be fixed on the lamellar basic material or and be present in the chamber that forms by basic material as granule as granule.

The present invention also provides the method for producing water-absorbent compositions, comprising:

The hydrogel of-preparation water-swellable,

-optional with steric hindrance or electrostatic spacers agent coating hydrogel and

-hydrogel is incorporated in polymer fiber substrate or the open cell polymer foams or introduces by form indoor of basic material or be fixed on the lamellar basic material.

Can be known by the hygienic articles of water-absorbent compositions production of the present invention itself, and narrate.They are diaper, sanitary towel and incontinence product such as incontinence pad preferably.The structure of these products is known.The narration of test method

Centrifugal reserve capacity (CRC)

This method is measured the free swell of hydrogel in tea-bag.The dried hydrogel (granularity grades 106-850 μ m) of 0.2000 ± 0.0050g is encased in the tea-bag of size 60 * 85mm, and sealing.This tea-bag soaks 30 minutes (polymer powder of sodium chloride solution/1g of 0.83L at least) then in 0.9 excessive weight % sodium chloride solution.Tea-bag under 250g centrifugal 3 minutes then.Measure amount of liquid by the tea-bag of weighing after centrifugal.

Load absorption (AUL) 0.7psi

The measuring cell of measuring AUL0.7psi is the Plexiglas graduated cylinder of internal diameter 60mm and height 50mm.What be bonded in its bottom surface is the stainless steel sift bottom with 36 μ m screen sizes.Measuring cell further comprises plastic plate with 59mm diameter and counterweight that can be in plastic plate is placed on measuring cell.The weight of plastic plate and counterweight amounts to 1345g.AUL0.7psi by measuring empty Plexiglas graduated cylinder and plastic plate weight and be recorded as W ₀Measure.The polymer that is used to form hydrogel of weighing 0.900 ± 0.005g (particle size distribution: 150-800 μ m), join in the Plexiglas graduated cylinder and be evenly distributed on the stainless steel sift very much then.Carefully plastic plate is placed in the Plexiglas graduated cylinder then, the whole device of weighing, weight record are W _aThen counterweight is placed on the plastic plate in the Plexiglas graduated cylinder.Then the ceramic filtering plate of diameter 120mm and porosity 0 is placed on the middle part of the Petri dish of diameter 200mm and height 30mm, introduce 0.9 enough weight % sodium chloride solution again, make the surface of liquid concordant with the filter plate surface, the surface of filter plate does not have wetted.Subsequently with the round filter paper of diameter 90mm and aperture＜20 μ m (from Schleicher ﹠amp; The S﹠amp of Sch ü ll; S589Schwarzband) be placed on the ceramic wafer.The Plexiglas graduated cylinder that will contain the polymer that is used to form hydrogel then with plastic plate and counterweight be placed on filter paper above, and kept there 60 minutes.Last during this period, the filter paper in Petri dish takes out whole device, takes out counterweight subsequently in the Plexiglas graduated cylinder.The Plexiglas graduated cylinder and the plastic plate of weighing together and containing the swelling hydrogel, weight record are W _b

AUL calculates by following equation:

AUL0.7psi[g/g]＝[W _b-W _a]/[W _a-W ₀]

Free swell rate (FSR)

With 1.00g (W _H) hydrogel evenly spread out and put in the weigh bottom of ship of the plastics of round bottom with about 6cm.The plastics ship of weighing is circular, the about 6cm of base diameter, and dark approximately 2.5cm and top are about 7.5cm * 7.5cm square.Use funnel with 20g (W then _U) synthetic urine solution join the center of the ship of weighing, this urine is by with the KCl of 2.0g, the Na of 2.0g ₂SO ₄, 0.85g NH ₄H ₂PO ₄, 0.15g (NH ₄) ₂HPO ₄, 0.19g CaCl ₂MgCl with 0.23g ₂Be dissolved in the 1L distilled water and prepare.The time of intact all fluids of record absorbed (with not existing the fluid that compiles to represent), be labeled as t _ACalculate the free swell rate by following formula then:

FSR＝W _U/(W _H×t _A)

Saline flow conductivity (SFC)

The test method of measuring SFC has been described in WO95/262/9.

Vortex time

The 0.9 weight %NaCl solution weighing of 50ml is joined in the 100ml beaker.When under 600rpm, stirring saline solution, be quickly poured into the hydrogel of 2.00g in the mode that can avoid agglomeration with magnetic stirring apparatus.Collection is calmed down the time (second) that flattens with the saline solution surface up to stirring the vortex that produces.

Gel strength

Measuring the Research on The Rheology of gel strength uses the CSL100 proof stress flow graph available from Carrimed to carry out.All measurements are at room temperature carried out.

Sample preparation: measure with the hydrogel particle with ratio sieve aperture fraction 300-400 μ m of 1 hour of swelling in 0.9 weight %NaCl solution of 1: 60 in advance and carry out.In order to prepare the sample that will measure, at first NaCl solution is joined in the 100mL beaker, under stirring, (magnetic force) adds the dried hydrogel granule gradually, and making does not have agglomeration to take place.Take out stirring rod subsequently, reuse film phonograph seal beaker and under this state, at room temperature place 1 hour so that swelling.In order to ensure with measure before the same terms, must follow this preparation method definitely, otherwise rheology measurement will suffer damage and measurement result distorted.

Measure operation: by the mode of oscillation of using plate-plate geometries (diameter 6cm) CarrimedCS rheometer measurement gel strength.For fear of slide effect, use sandblast plate system for this reason.Sample is placed on the base plate, slowly promotes this inclined-plane, this slit is slowly sealed.Measuring the slit is measured as 1mm and must be full of specimen material definitely fully.Gel strength is the elastic modelling quantity as the preswollen hydrogel of front defined, and to measure with the similar mode of the elastic modelling quantity in the linear viscoelastic region of sample, this is measuring same sample in test in advance.In order to measure gel strength subsequently, under constant frequency (1Hz), in linear viscoelastic region, carry out torque with mode of oscillation and mop up.If elastic characteristic, it is straight line that gained is measured curve, and it has quantized gel strength as the material constant of elastic solid (Hookean body).

The measurement result of being reported is the meansigma methods of 3 groups of measured values.

Following examples illustrate the present invention.

Embodiment

The embodiment of the invention 1:

In the polyethylene can of thorough insulating 10L capacity with plastic foam material, add the deionized water of 3600g and the acrylic acid of 1400g, add the tetraallyl oxygen base ethane of 4.0g and the allyl methacrylate of 5.0g subsequently.Add continuously down by 2 of 2.2g at 4 ℃, the initiator that the potassium persulfate (being dissolved in the deionized water of 150g) of the two amidine propane dihydrochlorides (being dissolved in the deionized water of 20g) of 2 '-azo, 4g and the ascorbic acid (being dissolved in the deionized water of 20g) of 0.4g are formed, and stir.Allow reaction solution place under the condition of stirring not having then.Polymerization has subsequently produced hard gel, and temperature rises to about 90 ℃ in this process.Carry out mechanical activation comminution after this, reuse 50 weight % sodium hydrate aqueous solutions transfer to pH6.0.Desiccant gel then grinds and is categorized as the particle size distribution of 100-850 μ m.This exsiccant hydrogel of 1kg is used the solution spray of being made up of the Ethylene glycol diglycidyl ether of the isopropyl alcohol of 60g deionized water, 40g and 1.0g in ploughshare shape mixer, subsequently 140 ℃ of following heat treatments 60 minutes.Product described herein has following performance:

CRC＝28.4g/g

AUL0.7psi＝25.1g/g

Gel strength=2350Pa

SFC＝35×10 ^-7cm ³s/g。

The embodiment of the invention 2:

In the polyethylene can of thorough insulating 30L capacity, add the deionized water of 14340g and the sorbitol triallyl ether of 42g with plastic foam material.The sodium bicarbonate of 3700g is suspended in this initial charge, so that avoid the speed of reaction solution excess foam formation to add the acrylic acid of 5990g gradually; Reaction solution is cooled to about 3-5 ℃.Add initiator down continuously at 4 ℃, be 2 of 6.0g, 2, the two amidine propane dihydrochlorides (being dissolved in the deionized water of 60g) of-azo, the potassium persulfate (being dissolved in the deionized water of 450g) of 12g and the ascorbic acid (being dissolved in the deionized water of 50g) of 1.2g, and thoroughly stir.Allow reaction solution place under the condition of stirring not having then.Polymerization has subsequently produced gel, and temperature rises to about 85 ℃ in this process.Subsequently this gel is transferred in the kneader, and transferred to 6.2 pH by adding 50 weight % sodium hydrate aqueous solutions.The gel that to pulverize is dry in air flow under 170 ℃ then, grinds and be categorized as the particle size distribution of 100-850 μ m.With 1 of the demineralized water of 2g RETEN 204 LS (available from polyamide-based amine-epichlorohydrin adducts of Hercules), 30g and 30g, the solution spray of 2-propylene glycol is subsequently 150 ℃ of following heat treatments 60 minutes in ploughshare shape mixer for this product of 1kg.Recorded following performance:

CRC＝32.3g/g

AUL0.7psi＝26.4g/g

Gel strength=1975Pa

SFC＝25×10 ^-7cm ³s/g。

The embodiment of the invention 3:

The WERNER ﹠amp that will have the 2L displacement volume with vacuum pump; The PFLEIDERER laboratory kneader is evacuated to 980 millibars, will be cooled to more about 25 ℃ and by feed nitrogen come deactivation in advance separately the monomer solution of preparation be drawn in this kneader.Monomer solution has the deionized water of following composition: 825.5g, the acrylic acid of 431g, the NaOH 50% of 335g, the pentaerythritol triallyl ether (available from the P-30 of Daiso) of the ethoxylated trimethylolpropane triacrylate of 4.5g (available from the SR9035 oligomer of SARTOMER) and 1.5g.In order to improve the deactivation effect, the kneader of finding time recharges with nitrogen subsequently.Repeat this operation 3 times.Suck the solution (being dissolved in the deionized water of 6.8g) of the sodium peroxydisulfate of 1.2g then, then after other 30 seconds, suck another solution of forming by the 0.024g ascorbic acid that is dissolved in the 4.8g deionized water.Behind nitrogen purging, 75 ℃ pre-thermal jacket heater circuit in bypass is switched to the kneader chuck, and blender speed is increased to 96rpm.After polymerization begins and reaches Tmax, the chuck heater circuit is switched to bypass, and batch of material is not appending polymerization 15 minutes under the heating/refrigerative situation, with postcooling and discharge.The gained gel particle grinds and is categorized into the particle size distribution of 100-850 μ m dry more than 100 ℃.This product of 500g in ploughshare shape mixer with 1 of the deionized water of the 2-oxazoline ketone of 2g, 25g and 10g, the 2-propylene glycol solution spray, subsequently 185 ℃ of following heat treatments 70 minutes.Recorded following performance:

CRC＝26.3g/g

AUL0.7psi＝23.8g/g

Gel strength=2680Pa

SFC＝50×10 ^-7cm ³s/g。

The embodiment of the invention 4:

The polymer of the embodiment of the invention 1 of 1000g and the Sipernat D17 (hydrophobic precipitated silica, the commercial product of Degussa AG, particle mean size 10 μ m) of 10g were mixed 15 minutes with ploughshare shape mixer.Tu Bu product has following performance like this:

CRC＝28.9g/g

SFC＝115×10 ^-7cm ³s/g

Vortex time=80s.

The embodiment of the invention 5:

With the polymer of the embodiment of the invention 1 of 1000g in ploughshare shape mixer with 50g by 90 parts by weight of deionized water and 10 weight portion aluminum sulfate (Al ₂(SO ₄) ₃) solution spray formed, append therein subsequently and mixed 30 minutes.The product of Huo Deing has following performance like this:

CRC＝27.2g/g

SFC＝160×10 ^-7cm ³s/g

Free swell rate=0.25g/gs.

The embodiment of the invention 6:

The polymer of the embodiment of the invention 1 of 1000g and the Sipernat 22 (hydrophilic precipitated silica, the commercial product of Degussa AG, particle mean size 100 μ m) of 8g were mixed 15 minutes with ploughshare shape mixer.Tu Bu product has following performance like this:

CRC＝29.5g/g

SFC＝100×10 ^-7cm ³s/g

Free swell rate=0.56g/gs.

The embodiment of the invention 7:

The polymer of the embodiment of the invention 2 of 1000g and the Kiesels  ure FK320 (hydrophilic precipitated silica, the commercial product of Degussa AG, particle mean size 15 μ m) of 10g were mixed 15 minutes with ploughshare shape mixer.Tu Bu product has following performance like this:

CRC＝32.6g/g

SFC＝95×10 ^-7cm ³s/g

Vortex time=58s.

The embodiment of the invention 8:

The solution spray that the polymer of the embodiment of the invention 2 of 1000g uses the SPAN20 by the Polymin G100 solution of 40g deionized water, 20g and 0.5g to form in ploughshare shape mixer appends therein subsequently and mixed 20 minutes.The product of Huo Deing has following performance like this:

CRC＝35.4g/g

SFC＝90×10 ^-7cm ³s/g

Vortex time=45s.

The embodiment of the invention 9:

The polymer of the embodiment of the invention 3 of 1000g was mixed 15 minutes with ploughshare shape mixer with the Sipernat D17 of 10g.Tu Bu product has following performance like this:

CRC＝25.8g/g

SFC＝210×10 ^-7cm ³s/g

Vortex time=105s.

The embodiment of the invention 10:

Solution spray with the polymer of the embodiment of the invention 3 of 1000g uses the SPAN20 by the Ethylene glycol diglycidyl ether of the deionized water of 50g, the polyvinylamine of 10g (K88), 0.1g and 0.5g to form in ploughshare shape mixer appends therein subsequently and mixed 20 minutes.After 80 ℃ of following heat treatments 1 hour, product has following performance in the laboratory drying baker:

CRC＝25.6g/g

SFC＝330×10 ^-7cm ³s/g

Vortex time=20s.

The comparative example 1:

In the polyethylene can of thorough insulating 10L capacity with plastic foam material, add the deionized water of 3600g and the acrylic acid of 1400g, add the chlorination tetraallyl ammonium of 14g subsequently.Add continuously down by 2 of 2.2g at 4 ℃, the initiator that the potassium persulfate (being dissolved in the deionized water of 150g) of the two amidine propane dihydrochlorides (being dissolved in the deionized water of 20g) of 2 '-azo, 4g and the ascorbic acid (being dissolved in the deionized water of 20g) of 0.4g are formed, and stir.Allow reaction solution place under the condition of stirring not having then.Polymerization has subsequently produced hard gel, and temperature rises to about 90 ℃ in this process.Carry out mechanical activation comminution after this, reuse 50 weight % sodium hydrate aqueous solutions transfer to pH6.0.Desiccant gel then grinds and is categorized as the particle size distribution of 100-850 μ m.This exsiccant hydrogel of 1kg is used the solution spray of being made up of the Ethylene glycol diglycidyl ether of the isopropyl alcohol of 40g deionized water, 40g and 0.5g in ploughshare shape mixer, subsequently 140 ℃ of following heat treatments 60 minutes.Product described herein has following performance:

CRC＝36.2g/g

AUL0.7psi＝25.9g/g

Gel strength=1580Pa

SFC＝8×10 ^-7cm ³s/g。

The comparative example 2:

The WERNER ﹠amp that will have the 2L displacement volume with vacuum pump; The PFLEIDERER laboratory kneader is evacuated to 980 millibars, will be cooled to more about 25 ℃ and by feed nitrogen come deactivation in advance separately the monomer solution of preparation be drawn in this kneader.Monomer solution has the deionized water of following composition: 825.5g, the acrylic acid of 431g, the NaOH 50% of 335g and the methylene-bisacrylamide of 3.0g.In order to improve the deactivation effect, the kneader and recharging with nitrogen subsequently of finding time.Repeat this operation 3 times.Suck the solution (being dissolved in the deionized water of 6.8g) of the sodium peroxydisulfate of 1.2g then, then after other 30 seconds, suck another solution of forming by the 0.024g ascorbic acid that is dissolved in the 4.8g deionized water.Behind nitrogen purging, 75 ℃ pre-thermal jacket heater circuit in bypass is switched to the kneader chuck, and blender speed is increased to 96rpm.After polymerization begins and reaches Tmax, the chuck heater circuit is switched to bypass, and batch of material is not appending polymerization 15 minutes under the heating/refrigerative situation, with postcooling and discharge.The gained gel particle grinds and is categorized into the particle size distribution of 100-850 μ m dry more than 100 ℃.Recorded following performance:

CRC＝29.4g/g

AUL0.7psi＝15.8g/g

Gel strength=1920Pa

SFC＝5×10 ^-7cm ³s/g。

The comparative example 3:

The comparative example's 1 of 1000g polymer and the Sipernat D17 (hydrophobic precipitated silica, the commercial product of Degussa AG, particle mean size 10 μ m) of 10g were mixed 15 minutes with ploughshare shape mixer.Tu Bu product has following performance like this:

CRC＝35.8g/g

SFC＝11×10 ^-7cm ³s/g

Vortex time=85s.

The comparative example 4:

With the comparative example's 1 of 1000g polymer in ploughshare shape mixer with 50g by 90 parts by weight of deionized water and 10 weight portion aluminum sulfate (Al ₂(SO ₄) ₃) solution spray formed, append therein subsequently and mixed 30 minutes.The product of Huo Deing has following performance like this:

CRC＝34.6g/g

SFC＝9×10 ^-7cm ³s/g

Free swell rate=0.48g/gs.

The comparative example 5:

The comparative example's 2 of 1000g polymer was mixed 15 minutes with ploughshare shape mixer with the Sipernat D17 of 10g.Tu Bu product has following performance like this:

CRC＝29.7g/g

SFC＝6×10 ^-7cm ³s/g

Vortex time=78s.

The comparative example 6:

Solution spray with the comparative example's 2 of 1000g polymer uses the SPAN 20 by the Ethylene glycol diglycidyl ether of the deionized water of 50g, the polyvinylamine of 10g (K88), 0.1g and 0.5g to form in ploughshare shape mixer appends therein subsequently and mixed 20 minutes.After 80 ℃ of following heat treatments 1 hour, product has following performance in the laboratory drying baker:

CRC＝27.8g/g

SFC＝15×10 ^-7cm ³s/g

Vortex time=35s.

The comparative example 7:

In the polyethylene can of thorough insulating 30L capacity, add the deionized water of 14340g and the sorbitol triallyl ether of 42g with plastic foam material.The sodium bicarbonate of 3700g is suspended in this initial charge, so that avoid adding gradually under the speed of reaction solution excess foam formation the acrylic acid of 5990g; Reaction solution is cooled to about 3-5 ℃.Add initiator down continuously at 4 ℃, be 2 of 6.0g, the two amidine propane dihydrochlorides (being dissolved in the deionized water of 60g) of 2 '-azo, the potassium persulfate (being dissolved in the deionized water of 450g) of 12g and the ascorbic acid (being dissolved in the deionized water of 50g) of 1.2g, and thoroughly stir.Allow reaction solution place under the condition of stirring not having then.Polymerization has subsequently produced gel, and temperature rises to about 85 ℃ in this process.Subsequently this gel is transferred in the kneader, and transferred to 6.2 pH by adding 50 weight % sodium hydrate aqueous solutions.The gel that to pulverize is dry in air flow under 170 ℃ then, grind and be categorized as the particle size distribution of 100-850 μ m, again with Aerosil 200 (pyrogenic silica, the commercial product of Degussa AG, the particle mean size 12nm) uniform mixing of 1.0 weight %.With 1 of the demineralized water of 2g RETEN 204 LS (available from polyamide-based amine-epichlorohydrin adducts of Hercules), 30g and 30g, the solution spray of 2-propylene glycol is subsequently 150 ℃ of following heat treatments 60 minutes in ploughshare shape mixer for this product of 1kg.Recorded following performance:

CRC＝31.8g/g

SFC＝25×10 ^-7cm ³s/g。

Vortex time=65s.

The comparative example 8:

In the polyethylene can of thorough insulating 30L capacity, add the deionized water of 14340g and the sorbitol triallyl ether of 42g with plastic foam material.The sodium bicarbonate of 3700g is suspended in this initial charge, so that avoid adding gradually under the speed of reaction solution excess foam formation the acrylic acid of 5990g; Reaction solution is cooled to about 3-5 ℃.Add initiator down continuously at 4 ℃, be 2 of 6.0g, the two amidine propane dihydrochlorides (being dissolved in the deionized water of 60g) of 2 '-azo, the potassium persulfate (being dissolved in the deionized water of 450g) of 12g and the ascorbic acid (being dissolved in the deionized water of 50g) of 1.2g, and thoroughly stir.Allow reaction solution place under the condition of stirring not having then.Polymerization has subsequently produced gel, and temperature rises to about 85 ℃ in this process.Subsequently this gel is transferred in the kneader, and transferred to 6.2 pH by adding 50 weight % sodium hydrate aqueous solutions.The gel that to pulverize is dry in air flow under 170 ℃ then, grinds and be categorized as the particle size distribution of 100-850 μ m.This product of 1kg is used the aluminum sulfate Al of 2g RETEN 204 LS (available from polyamide-based amine-epichlorohydrin adducts of Hercules), 5g in ploughshare shape mixer ₂(SO ₄) ₃, the demineralized water of 30g and 30g 1, the solution spray of 2-propylene glycol is subsequently 150 ℃ of following heat treatments 60 minutes.Recorded following performance:

CRC＝31.5g/g

SFC＝24×10 ^-7cm ³s/g。

Vortex time=73s.

Claims (14)

1,, be characterised in that to have feature before the following coating with the hydrogel of the water-insoluble water-swellable of steric hindrance or electrostatic spacers agent coating:

-at least the load absorption of 20g/g (AUL) (0.7psi),

-the gel strength of 1600Pa at least.

2,, be characterised in that to have following coating back feature as the desired hydrogel of claim 1:

-centrifugal the reserve capacity (CRC) of 24g/g at least,

-at least 30 * 10 ^-7Cm ³The saline flow conductivity (SFC) of s/g and

-at least 0.15g/g free swell rate (FSR) and/or be no more than the vortex time of 160s.

3, as claim 1 or 2 desired hydrogels, wherein the steric hindrance interval dose is selected from bentonite, zeolite, active carbon and silicon dioxide.

4, as claim 1 or 2 desired hydrogels, wherein the electrostatic spacers agent is a cationic polymer.

5, as the desired hydrogel of claim 3, wherein the steric hindrance interval dose is applied on the surface of hydrogel with the amount of 0.05-5 weight %, based on the gross weight of the hydrogel after the coating.

6, contain water-absorbent compositions just like the hydrogel of each desired water-insoluble water-swellable among the claim 1-5.

7, as the desired water-absorbent compositions of claim 6, wherein the hydrogel of water-swellable is embedded in polymer fiber substrate or the open cell polymer foams as granule, be fixed on the lamellar basic material or as granule be present in by basic material form indoor.

8, production comprises as the method for the desired water-absorbent compositions of claim 6:

The hydrogel of-preparation water-swellable,

-with steric hindrance or electrostatic spacers agent coating hydrogel and

-hydrogel is incorporated in polymer fiber substrate or the open cell polymer foams or introduces by form indoor of basic material or be fixed on the lamellar basic material.

9, each the desired water-absorbent compositions as claim 6 and 7 is used to produce the hygienic articles of absorption aqueous fluid or the purposes of other goods.

10, the hygienic articles of each desired water-absorbent compositions between permeable top sheet of liquid and liquid impermeability tergite, containing just like claim 6 and 7.

11, diaper, sanitary towel and incontinence with product form as the desired hygienic articles of claim 10.

12, improve the method for the performance profile of water-absorbent compositions, comprise with the permeability, capacity and the swelling ratio that improve water-absorbent compositions as the hydrogel of each defined water-insoluble water-swellable among the claim 1-5.

13, measure the method for water-absorbent compositions with high osmosis, capacity and swelling ratio, centrifugal reserve capacity (CRC), saline flow conductivity (SFC) and the free swell rate (FSR) of the hydrogel after comprising the load absorption (AUL) and the gel strength of the uncoated hydrogel of measuring set water-absorbent compositions and measuring coating, and measure the water-absorbent compositions that its hydrogel shows performance range described in claim 1 or 2.

14, the hydrogel as each defined water-insoluble water-swellable among the claim 1-5 is used to absorb aqueous fluid to improve the purposes of permeability, capacity and swelling ratio in hygienic articles or other goods.