CN101076359A

CN101076359A - Absorbent members comprising modified water absorbent resin for use in diapers

Info

Publication number: CN101076359A
Application number: CN 200580042472
Authority: CN
Inventors: 松本真; 三神吉郎; 池内广幸; 鸟井一司; 岩本卓; 安德烈亚斯·弗洛尔; 托斯滕·林德纳
Original assignee: Procter and Gamble Ltd
Current assignee: Procter and Gamble Ltd; Procter and Gamble Co
Priority date: 2004-12-10
Filing date: 2005-12-09
Publication date: 2007-11-21
Also published as: JP2006169267A; ZA200704319B

Abstract

An absorbent member for use in disposable diapers, wherein the absorbent member comprises a modified water absorbent resin. The modified water absorbent resin is made according to the method which comprises a) mixing a water absorbent resin and a water-soluble radical polymerization initiator or a heat-degradable radical polymerization initiator without addition of an ethylenically unsaturated monomer and b) irradiating the resultant mixture with active energy rays. The method is particularly capable of exalting the absorbency against pressure and the saline flow conductivity.

Description

The absorption component that is used for the water-absorbing resin that comprises modification that uses at diaper

Invention field

A kind of absorption component of using at diaper of being used for, wherein said absorption component comprises the water-absorbing resin of modification.By being shone, activity energy ray (active energy ray) makes this water-absorbing resin modification on the water-absorbing resin.But described water-absorbing resin mixes with the radical polymerization initiator of water-soluble radical polymerization initiator or thermal degradation, and need not to add ethylenically unsaturated monomers.

Background of invention

Up to now, water-absorbing resin is as a kind of component of hygienic material (as cotton wool, disposable diaper and be used for other kind body fluid absorption agent).As the instantiation of water-absorbing resin, can quote the hydrolyzate of the hydrolyzate of starch-acrylonitrile grafting polymer, neutral starch-acrylic acid-grafted polymer, saponified vinyl acetate-acrylate copolymer, acrylonitrile copolymer or acrylamide copolymer, their cross-linking products and the neutral cross-linked acrylic acid of part.These water-absorbing resins always have the internal crosslinking structure and are presented in the water and do not dissolve.

Expect that the characteristic that these water-absorbing resins have comprises for example high absorptive capacity, ideal infiltration rate, high-gel strength and make us the well-content necessary suction force that absorbs water from medium.Because water absorbing properties is subjected to the influence of crosslink density, so they needn't show the positive correlation each other that following enforcement is indicated: the increase of crosslink density causes the increase of gel strength, but cause the absorbed water yield to reduce.Especially absorptive capacity becomes contradictory relation with for example infiltration rate, gel strength and suction force.Therefore, the water-absorbing resin that has obtained the enhanced absorption capacity may prevent uneven moisture absorption and the accumulative part of the part of formation own when water absorbing resin particle contacts with water, be not diffused in the interior extreme reduction that causes infiltration rate of whole volumes of water absorbing resin particle simultaneously owing to moisture.

Water-absorbing resin in order to relax this phenomenon and to obtain to have high absorptive capacity and relative infiltration rate of being satisfied with can obtain to give the method that water absorbing resin particle is coated with the surface of surfactant or fixed hydrocarbon.This method has improved the dispersibility of initial absorption moisture really, but is not bringing effect of sufficient aspect absorbability that strengthens single resin particle and the suction force.

As a kind of produce high-hydroscopicity can the means of polymer of polyacrylic acid type, United States Patent (USP) 4,910,250 have proposed a kind of method, it comprises makes that have polyacrylic part alkali metal salt heats in the presence of the water-soluble peroxide radical initiator as key component and Aquo-composition with lower crosslink density, thereby introduces crosslinked within it by radical crosslinking.It is difficult to uniform distribution internal crosslinking and the difficult crosslink density of adjusting in polymer.Therefore, adopted preparation comprise lower crosslink density the water-soluble polypropylene acid gel polymer then with this polymer with add the method that the persulfate on it heats to as polymerization initiator.United States Patent (USP) 4,910,250 advocate to realize by the amount of adjusting the initiator that is added the accurate control (because the internally crosslinked even existence of polymer) of crosslink density, obtain perfect water absorbing properties and obtain not having the water-absorbing resin of viscosity.

Although the persulfate that is used in the above-mentioned United States Patent (USP) 4,910,250 can be by adding thermal degradation, but its also ultraviolet degradation and produce free radical.Because persulfate is fulfiled function as polymerization initiator.Therefore when being exposed to radiation, the aqueous solution of water-soluble vinyl monomer carries out polyreaction and radical crosslinking simultaneously and produces hydrogel.Understood by people by the reaction system of adding hydrophilic polymer component, photochemical polymerization initiator and cross-linking agent together and they form internal crosslinking with ultraviolet radiation.

Simultaneously, the method for water-absorbing resin being carried out surface treatment and giving enhanced crosslink density thereon with cross-linking agent also can be understood from for example United States Patent (USP) 4,666,983 and United States Patent (USP) 5,422,405.Make reactive functionality can be present on its surface such as the water-absorbing resin of being quoted in the aforementioned patent document.By add can and the surface crosslinking agent of functional group reactions realize introducing crosslinked between the functional group, thereby might give the surface that water-absorbing resin strengthens crosslink density, even and make that water-absorbing resin obtains to depress also good water absorbing properties adding.

In addition, because using above-mentioned surface crosslinking agent need be used to form crosslinked reaction at high temperature carries out for a long time and needs cross-linking agent to continue to exist under invariant state, United States Patent (USP) 4,783,510 have proposed the method comprise the aqueous solution contact pressure resin of peroxide radical initiator and to heat resin by making, and it has realized introducing near resin surface the polymer molecular chain crosslinked by the degraded of radical initiator.In the working example of this method, show that water-absorbing resin with the enhanced absorption capacity superheated steam by with 130 ℃ the time is realized heating to obtain in 6 minutes.

An object of the present invention is to make water-absorbing resin between absorptive capacity and infiltration rate, have good balance with in the surface-crosslinked introducing water-absorbing resin.This water-absorbing resin uses at the absorption component that is used for diaper.Usually, this purpose need have at least two kinds and can act on the water-absorbing resin with the cross-linking agent of the functional group that is present in the lip-deep functional group reactions of water-absorbing resin.As the instantiation of the cross-linking agent of this character, can quote polyhydric alcohol, multivalence glycidyl ether, halogenation epoxide, multivalence aldehyde, multivalence amine and multivalent metal salt.Because cross-linking agent has hypoergia, therefore corresponding reaction needed at high temperature carries out and needs sometimes remaining under the heated condition for a long time.Therefore, reaction needed lot of energy and time.

United States Patent (USP) 4,783, disclosed employing peroxide radical initiator carries out and needs high reaction temperature and humidity to carry out necessary moisture to be used for keeping reacting for effective reaction as the surface treatment method of cross-linking agent in 510.Therefore, it exists also in order to enhance productivity.

The present invention aims to provide the absorption component that comprises the water-absorbing resin of making according to the method that is used to produce water-absorbing resin, and described water-absorbing resin is modified so that in production efficiency and good such as performance aspect withstand voltage absorbability, infiltration rate, gel strength and the permeability for liquids.

Summary of the invention

The present invention relates to be used for the absorption component that uses at disposable diaper, wherein said absorption component comprises the water-absorbing resin of the modification of producing according to described method, and described method comprises

A) mixed water-absorbent resin and water-soluble radical polymerization initiator and do not add ethylenically unsaturated monomers and

B) with active energy roentgenization gained mixture.

In addition, the present invention relates to be used for the absorption component that uses at disposable diaper, wherein said absorption component comprises the water-absorbing resin of powdered modification, and described water-absorbing resin comprises that by polymerization the monomer component of the acrylic acid (salt) as key component obtains, and is characterized in that having

(i) be not less than 40 (10 ^-7Cm ³Sg ^-1) the saline flow conductivity,

(ii) be no more than 95% solids content and

(iii) be no more than the residual monomer content of 150ppm.

The invention still further relates to and be used for the absorption component that uses at disposable diaper, wherein said absorption component comprises the water-absorbing resin of the modification of producing according to described method, and described method comprises

A) mixed water-absorbent resin and persulfate and do not add ethylenically unsaturated monomers,

B) with step (a) simultaneously or step (a) add before the mixed aid that is different from water and

C) with active energy roentgenization gained mixture.

In another embodiment, the present invention relates to be used for the absorption component that uses at disposable diaper, wherein said absorption component comprises the water-absorbing resin of the modification of producing according to described method, and described method comprises

A) mixed water-absorbent resin and persulfate and do not add ethylenically unsaturated monomers and

B) with active energy roentgenization gained mixture,

Wherein said water-absorbing resin has acidic-group and the neutralization ratio in 50% to 75% molar range (mole percent of neutral acidic-group in whole acidic-groups).

And the invention still further relates to and be used for the absorption component that uses at disposable diaper, wherein said absorption component comprises the water-absorbing resin of the modification of producing according to described method, and described method comprises

C) with active energy roentgenization gained mixture,

The accompanying drawing summary

Though this description it is believed that by following legend and incidental explanation to understand the present invention better that by particularly pointing out and clearly claimed claim of the present invention is drawn a conclusion wherein similar components is represented with identical reference number.

Fig. 1 is the sketch map of the measuring device that is used to measure saline flow conductivity (SFC).

The reference number explanation

The 31-jar

The 32-glass tubing

The sodium-chloride water solution of 33-0.69% weight

34-is furnished with the L letter pipe of tap

The 35-tap

The 40-container

The 41-pond

The metal gauze that 42-is made by rustless steel

The metal gauze that 43-is made by rustless steel

The swollen gel of 44-

The 45-glass filter

The 46-piston

The 47-piston hole

The 48-collecting vessel

The 49-pan scale

Detailed Description Of The Invention

Studying in great detail of production being had the method for the water-absorbing resin of modified surface carries out disclosed when up to now as the persulfate of (thermal degradation) radical polymerization initiator with active can radiation exposure the time, this persulfate produces free radical and so that water-absorbing resin can easily form cross-linked structure in its surface. In addition, it is found that the method realizes surface-crosslinked introducing and need not to use is the surface crosslinking agent that is used for the solvent of conventional method, and so that the water-absorbing resin of producing shows in the balance of water absorbing properties good.

Up to now, depend on the kind that is incorporated into the surface crosslinking agent in the correspondent composition, surface-crosslinkedly need to process under the high temperature in 100 ℃ to 300 ℃ scopes. Method for the manufacture of the water-absorbing resin that is used for absorption component of the present invention can be only by realizing that surface-crosslinked introducing need not to use surface crosslinking agent by radiation exposure with active. Therefore, water-absorbing resin can be modified need not to be exposed under the high temperature, and can prevent in modifying process through degradation.

In addition, because persulfate is dissolvable in water in the water, so it is dissolvable in water in the aqueous solution and with water-absorbing resin and mixes, thereby can guarantee in resin formation surface-crosslinked uniformly. Therefore, the water-absorbing resin of modification is really good in the performance of some characteristics, the suction force that has such as absorptive capacity, infiltration rate, gel strength and expectation water-absorbing resin.

Produce to be used for the method for water-absorbing resin of modification of absorption component of the present invention by realizing surface-crosslinked with active energy radiation exposure. Therefore, compare with conventional method, it can be to the water-absorbing resin modification within the of short duration period.

First aspect of the present invention relates to the method for the water-absorbing resin of producing the modification that is used for absorption component of the present invention, and wherein said method comprises

A) mixed water-absorbent resin and water-soluble radical polymerization initiator and do not add ethylenically unsaturated monomers, and

B) with active energy radiation exposure gained mixture.

Now, will be in following detailed description for the production of the method for the water-absorbing resin of modification as described in the present invention.

Second aspect of the present invention relates to the method for the production of the water-absorbing resin of modification, and described method comprises

A) but mixed water-absorbent resin does not add ethylenically unsaturated monomers with the radical polymerization initiator of thermal degradation, and

B) with active energy radiation exposure gained mixture.

(a) water-absorbing resin

The water-absorbing resin that can be used in the absorption component of the present invention is a kind of cross-linked polymer, and it has the ability of swelling in water and water insoluble, therefore can form hydrogel. Term used herein " swelling ability in the water " refers to that the free swell degree (be ability that sample absorb physiological saline) of given sample in the sodium-chloride water solution (physiological saline) of 0.9% weight is not less than 2g/g substantially, and preferred in 5 to 100g/g scope or in 10 to 60g/g scope. Term " water insoluble " refers to that the uncrosslinked polymer (can extract polymer) that extracts in the water-absorbing resin should perhaps be no more than 25% weight in the scope of 0 to 50% weight, perhaps is no more than 15% weight, perhaps is no more than 10% weight. The numerical value of free swell degree and can extract those that polymer finds for the assay method of appointment in the working example of hereinafter quoting. Term " modification " refers to that all physics and the chemical action of carrying out at water-absorbing resin, purpose are so that water-absorbing resin can for example obtain surface-crosslinked, pore-forming and give hydrophily and hydrophobicity within it.

The water-absorbing resin that can be used in the absorption component of the present invention needn't be subject to special restriction, but only needs and can obtain by the monomer component that utilizes any known method polymerization substantially to comprise ethylenically unsaturated monomers.

Ethylenically unsaturated monomers needn't be subject to special restriction, but is preferably the monomer that has unsaturated double-bond at its end. As the instantiation of monomer in this description, can quote anionic monomer such as (methyl) acrylic acid, 2-(methyl) acryloyl ethane sulfonic acid, 2-(methyl) acryloyl propane sulfonic acid, 2-(methyl) acrylamide-2-methyl propane sulfonic acid, vinyl sulfonic acid and styrene sulfonic acid and salt thereof; The monomer that comprises non-ionic hydrophilic group replaces (methyl) acrylamide, 2-hydroxyethyl (methyl) acrylate and 2-hydroxypropyl (methyl) acrylate such as (methyl) acrylamide, N-; Comprise amino unsaturated monomer such as N, N-dimethylaminoethyl (methyl) acrylate, N, N-diethyl aminoethyl (methyl) acrylate, N, N-diethyl amino propyl group (methyl) acrylate and N, N-dimethyl aminopropyl (methyl) acrylate and their quaternized products. These monomers can use separately or use with the form of mixtures of two or more compositions. In above cited monomer, (methyl) acrylic acid, 2-(methyl) acryloyl ethane sulfonic acid, 2-(methyl) acrylamide-2-methyl propane sulfonic acid and salt thereof, N, N-dimethylaminoethyl (methyl) acrylate and quaternised N, N-dimethylaminoethyl (methyl) acrylate and (methyl) acrylamide prove preferably, and acrylic acid and salt thereof prove especially preferred.

When acrylates is used as monomer, consider that water-absorbing resin absorbs the ability of moisture, the monovalence acrylates of selecting in acrylic acid alkali metal salt, ammonium salt and amine salt proves favourable. Acrylic acid alkali metal salt and/or the acrylates that can select in sodium salt, lithium salts and sylvite prove favourable.

In the production of water-absorbing resin, can use other monomer component that is different from above cited monomer, institute's consumption should not weaken effect of the present invention. As the instantiation of this other monomer component, can quote hydrophobic monomer such as the aromatic ethylene unsaturated monomer with the carbon number in 8 to 30 scopes, the aliphatic vinylation unsaturated monomer with the carbon number in 2 to 20 scopes, (methyl) alkyl acrylate of having the alicyclic ethylene unsaturated monomer of the carbon number in 5 to 15 scopes and comprising the alkyl with carbon number in 4 to 50 scopes. Based on the above-mentioned vinylation unsaturated monomer of 100 parts of weight, the ratio of this hydrophobic monomer is usually in the scope of 0 to 20 part of weight. If the ratio of hydrophobic monomer surpasses 20 parts of weight, then this excessive reduction that may cause the water absorbing properties of the water-absorbing resin of producing.

The water-absorbing resin that is used for absorption component of the present invention does not dissolve by forming internal crosslinking. This internal crosslinking can be the product that obtains by the self-crosslinking that does not use crosslinking agent. It can form by utilizing internal crosslinking agent, and described internal crosslinking agent has in molecular cell and is no less than two polymerizable unsaturated groups and/or is no less than two reactive functionality.

The internal crosslinking agent of this description needn't be subject to special restriction. Instantiation as internal crosslinking agent, can quote N, N '-di-2-ethylhexylphosphine oxide (methyl) acrylamide, N-methylol (methyl) acrylamide, glycidyl (methyl) acrylate, (gathering) ethylene glycol bisthioglycolate (methyl) acrylate, (gathering) propane diols two (methyl) acrylate, glycerine three (methyl) acrylate, glycerine acrylate acrylate, (methyl) acrylic acid multivalent metal salt, trimethylolpropane tris (methyl) acrylate, triallylamine, triallyl cyanurate, triallyl isocyanurate, tricresyl phosphate propylene, DGEEG, (gathering) propanetriol-diglycidyl-ether and polyethyleneglycol diglycidylether. These internal crosslinking agents can two or more compositions form of mixtures use.

The amount of used internal crosslinking agent can be in 0.0001% to 1% mole scope, perhaps in 0.001% to 0.5% mole scope, perhaps in 0.005% to 0.2% mole scope. If 0.0001% mole of this quantity not sufficient, then this deficiency will cause stoping internal crosslinking agent to be introduced in the resin. Conversely, if should amount surpass 1% mole, then this excessively may cause excessively improving the gel strength of water-absorbing resin and reduce absorptive capacity. For the inside by using internal crosslinking agent that cross-linked structure is introduced polymer, can be before monomer polymerization, during or internal crosslinking agent is added in the reaction system after being neutralized afterwards or producing polymer.

In order to produce water-absorbing resin, can in its aqueous solution, will comprise above-mentioned monomeric monomer component and internal crosslinking agent polymerization.The polymerization initiator that can be used in this situation is a water-soluble radical polymerization initiator, comprises persulfate such as potassium peroxydisulfate, Ammonium persulfate. and sodium peroxydisulfate; Peracetic acid potassium, peracetic acid sodium, potassium percarbonate, SODIUM PERCARBONATE and tert-butyl hydroperoxide; Hydrogen peroxide; Azo-compound as 2,2 '-azo two (2-amidine propane)-dihydrochloride and photochemical polymerization initiator for example comprise 2-hydroxy-2-methyl-1-phenylacetone.Above-mentioned water-soluble radical polymerization initiator can make up so that be used as the initiator of oxidoreduction type with Reducing agent (as sulphite, L-ascorbic acid or ferric salt).

Monomeric concentration needn't be received special restriction in the above-mentioned monomer solution, but can be in the scope of 15% to 90% weight or in the scope of 35% to 80% weight.If this concentration less than 15% weight, then this deficiency will must consumption of calorie because the gained hydrogel has too much water content and drying time aspect be in a disadvantageous position.

The method that polymerization is adopted needn't be subjected to special restriction, but can select in known method, and described method comprises for example polymerisation in solution, inverse suspension polymerization, precipitation polymerization and polymerisation in bulk.In these methods, aqueous solution polymerization comprise be dissolved in monomer in the aqueous solution and in aqueous solution to its polymerization, and inverse suspension polymerization proves especially favourable because of the easy performance of the control polyreaction and the water-absorbing resin of producing.

In causing above-mentioned polyreaction, above-mentioned polymerization initiator is used to realize this initiation.Except above-mentioned polymerization initiator, active energy ray such as ultraviolet, electron radiation and gamma-rays also can use separately or be used in combination with polymerization initiator.Although the temperature in the initiated polymerization depends on the kind of used polymerization initiator, it can be in 15 ℃ to 130 ℃ scope or in 20 ℃ to 120 ℃ scope.If the above-mentioned scope of the temperature departure of initiated polymerization, thereby then this departs from and will increase institute's residual monomer in the water-absorbing resin of producing and make self-crosslinking reaction excessively carry out being in a disadvantageous position aspect the water absorbing properties of reduction water-absorbing resin.

Term " inverse suspension polymerization " is meant the polymerization that carries out on the monomer solution in being suspended in hydrophobic organic solvent.It for example is disclosed in the United States Patent (USP) 4,093,776,4,367,323,4,446,261,4,683,274 and 5,244,735.Term " aqueous solution polymerization " is meant in the method for not using polymerization single polymerization monomer aqueous solution under the dispersion solvent.It is disclosed in for example United States Patent (USP) 4,625,001,4,873,299,4,286,082,4,973,632,4,985,518,5,124,416,5,250,640,5,264,495,5,145,906 and 5,380,808 and European patent 0,811,636,0,955,086 and 0,922,717 in.The monomer and the initiator that illustrate as an example in these polymerizations and quote can be applicable to the present invention.

Aqueous solution polymerization can be used such as carrying out with resulting polymers in the alkali compounds of sodium hydroxide or sodium carbonate subsequently by the acrylic acid of neutral acrylic acid of polymeric part or polymeric acid form.Therefore, be used for water-absorbing resin of the present invention and can have acidic-group and concrete neutralization ratio (neutral acidic-group is in the mole percent of whole acidic-groups).In this case, the neutralization ratio of the water-absorbing resin of being produced (mole percent of neutral acidic-group in whole acidic-groups) is in 25% to 100% mole scope, perhaps in 50% to 90% mole scope, perhaps in 50% to 75% mole scope, perhaps even in 60% to 70% mole scope.Therefore, the method of the water-absorbing resin of production modification is provided according to the preferred embodiments of the invention, described method comprises a) mixed water-absorbent resin and water-soluble radical polymerization initiator and does not add ethylenically unsaturated monomers, and b) with active energy roentgenization gained mixture, wherein said water-absorbing resin has acidic-group and the neutralization ratio in 50% to 75% molar range (mole percent of neutral acidic-group in whole acidic-groups).

The product of polyreaction is generally the gelationus cross linked polymer of water-setting.Although the present invention allow the gluey cross linked polymer of this water-setting with its constant form as water-absorbing resin, preferred polymers is dried to hereinafter with specifically described water content (%) [100-(solids content) is (%)].

Incidentally, the present invention comes the water-absorbing resin modification by utilizing hereinafter specifically described water-soluble radical polymerization initiator or thermal degradation radical polymerization initiator (being called in this manual, " radical polymerization initiator " jointly) and active energy ray.This modification originates from the effect of the radical pair main polymer chain that is produced by polymerization initiator.Therefore, this modification is not necessarily limited to the water-absorbing resin that obtains by the above-mentioned water miscible vinylation unsaturated monomer of polymerization, but can realize on the water-absorbing resin of for example cross-linking polyvinyl alcohol, crosslinked poly(ethylene oxide), cross-linked poly-aspartic acid and cross-linked carboxymethyl cellulose.

The water-absorbing resin that is used for absorption component of the present invention can be the powdery water-absorbing resin, and it obtains by the monomer that polymerization has especially as the acrylic acid (salt) of its key component.The gluey cross linked polymer of water-setting that obtains by polyreaction can dryly also grind to form water-absorbing resin subsequently.It is dry to utilize exsiccator such as hot-air drier to realize in 100 ℃ to 220 ℃ scope or under the temperature in 120 ℃ to 200 ℃ scopes.

In order to be used to pulverize, be sorted in Particle TechnologyHandbook (front page in name with Cheng Fenji, Particle Technology Association edits) table 1.10 in shearing primary breaker, collision shredder and high speed rotating grinder in, can especially preferably adopt have at least such as cutting, shear, bump and friction become at least a Cheng Fenji in the powder mechanism.

In response Cheng Fenji described above, can especially advantageously adopt to cut and to shear Cheng Fenji as dominant mechanism.Roll-type (roller rotation type) flour mill can be used as preferred embodiment and quotes.

The water-absorbing resin that is used for absorption component of the present invention is preferably powder-form.It can be and comprises particulate powdery water-absorbing resin, and described particulate diameter is (as defined by sieve classification) in the scope of 150 to 850 μ m, and ratio is in 90% to 100% scope by weight or by weight in 95% to 100% the scope.For example, when the water-absorbing resin of the modification with the particle diameter that surpasses 850 μ m was used for disposable diaper, its skin to user was given discomfort and may be caused breaking of diaper topsheets.If diameter surpasses by weight 10% less than the granule ratio of 150 μ m based on the weight of water-absorbing resin, then fine powder will scatter and choke structure in use, and may reduce the water absorbing properties of the water-absorbing resin of modification.The weight average particle diameter of water-absorbing resin is in the scope of 10 to 1,000 μ m or in the scope of 200 to 600 μ m.If weight average particle diameter less than 10 μ m then may prove disadvantageous based on safety and healthy this deficiency of consideration.Conversely, if it surpasses 1,000 μ m, then this excessive water-absorbing resin that may prevent is used for for example disposable diaper.Above-mentioned particle diameter is the value that the method for the particle size distribution measuring described by the working example that is used for hereinafter quoting is measured.

In addition or alternatively, the water-absorbing resin that is used for absorption component of the present invention can have the water-absorbing resin precursor of low neutralization ratio and this water-absorbing resin precursor mixed with matrix and obtains by production.Multifunction surface inorganic agent routine is used for surface treatment (surface-crosslinked).The performance that the multifunction surface inorganic agent has make they in water-absorbing resin with carboxyl (COOH) reaction but with its salt (for example ,-COONa) reaction.Therefore, even crosslinked can followingly the acquisition: preparation ethylenically unsaturated monomers mixture (for example, the mixture of acrylic acid and sodium acrylate), wherein-the COOH/-COONa ratio is adjusted in the suitable scope in advance, polymerization gained mixture with production have uniform distribution within it-COOH and-water-absorbing resin of COONa group, carry out surface-crosslinked with the multifunction surface cross-linking agent to the gained water-absorbing resin.On the other hand, when water-absorbing resin comprise by polymerization such as acrylic acid acids vinylation unsaturated monomer as the monomer mixture of important component then with alkali compounds such as sodium hydroxide and sodium carbonate in and resulting polymers when obtaining, the gained water-absorbing resin has less extracted polymer content and high-gel strength.Yet when carrying out with the multifunction surface inorganic agent when surface-crosslinked, it has the water absorption of reduction, this be because-COOH and-the COONa group is not evenly distributed in the water-absorbing resin.Therefore, the water-absorbing resin of producing with a kind of method in back can not carry out with this routine of multifunction surface inorganic agent surface-crosslinked ideally.Conversely, the method that water-absorbing resin adopted that is used for absorption component of the present invention according to manufacturing, because water-soluble radical polymerization initiator or thermal degradation radical polymerization initiator are by extracting hydrogen to generate free radical and to utilize the free radical coupling to impel crosslinked in main chain, rather than by with-COOH reaction, so cross-linking reaction be not subjected to-whether the COOH group be evenly distributed on the influence in the water-absorbing resin.Therefore, the method that water-absorbing resin adopted that is used for absorption component of the present invention according to manufacturing, by polymerization single polymerization monomer or comprise such as acrylic acid acids ethylenically unsaturated monomers as the monomer mixture of key component to obtain to have the water-absorbing resin precursor of low neutralization ratio, can be modified with alkali compounds such as sodium hydroxide or the sodium carbonate water-absorbing resin that this water-absorbing resin precursor obtains that neutralizes then, the water-absorbing resin of the gained modification that obtains by this method demonstrates high-gel strength and good water absorption.

In the present invention, statement " the water-absorbing resin precursor with low neutralization ratio " is meant and has low neutralization ratio (mole percent of neutral acidic-group in whole acidic-groups) or the water-absorbing resin precursor that does not have neutral acidic-group (being that neutralization ratio is zero), and typically be meant to have in about 0 to 50% molar range, perhaps the water-absorbing resin precursor of the neutralization ratio in about 0 to 20% molar range (mole percent of neutral acidic-group in whole acidic-groups).This water-absorbing resin precursor with low neutralization ratio can obtain by method same as described above, described method comprises the monomer that comprises acidic-group such as acrylic acid monomer mixture as key component by use, and wherein neutralization ratio can be adjusted in the above scope.Therefore will omit the detailed explanation of precursor.

The water content of the water-absorbing resin that uses in the method for the water-absorbing resin that is used for the contemplated modification that is used for absorption component of production the present invention is not particularly limited, as long as water-absorbing resin has flowability.Water-absorbing resin in the time of 180 ℃ after dry three hours has in 0 to 20% weight range, perhaps in 0 to 10% weight range, and the perhaps water content in 0 to 5% weight range.

The water-absorbing resin that is used for absorption component of the present invention is not limited to the product in the said method, but can be the product that obtains by some other method.Although the water-absorbing resin that obtains by said method is not carry out surface-crosslinked water-absorbing resin, but the method for the water-absorbing resin that is used for production modification of the present invention also can adopt in advance and carry out surface-crosslinked water-absorbing resin with polyhydric alcohol, multivalence epoxide, alkylene carbonate or oxazolidinone compounds.

(b) water-soluble radical polymerization initiator

The method of water-absorbing resin that production is used for the modification of absorption component of the present invention comprises mixes water-soluble radical polymerization initiator and above-mentioned water-absorbing resin and does not add ethylenically unsaturated monomers.Up to now, the surface-crosslinked of water-absorbing resin generally realized by mixing surface crosslinking agent.Mix surface crosslinking agent and cause being present in the functional group on the resin surface and the strong chemical bonding of surface crosslinking agent, and therefore in resin surface, introduced stable surface-crosslinked structure.Then, by the chain length of suitable selection surface crosslinking agent, might conveniently adjust the distance between crosslinked.The amount of the surface crosslinking agent that mixes by adjustment might be controlled crosslink density.Yet the present invention has proved and can only make the water-absorbing resin modification by adopting water-soluble radical polymerization initiator to need not to mix above-mentioned surface crosslinking agent, has been to introduce cross-linked structure to the surface of water-absorbing resin specifically.It is to prevent water solublity radical initiator and ethylenically unsaturated monomers reaction that the present invention utilizes the statement purpose of " not adding ethylenically unsaturated monomers ", thereby avoids by absorbing the consumption that activates the water-soluble radical polymerization initiator that causes on the resin surface before the effect with active energy roentgenization.

In the present invention, although it is also unclear with the reason of the surface-crosslinked formation of active energy ray by water-soluble radical polymerization initiator, even but think and lacking inference of true susceptible of proof that cross-linked structure forms under the situation of cross-linking compounds, promptly activatory water-soluble radical polymerization initiator acts on the several sections that is present in lip-deep main chain of water-absorbing resin or side chain by being exposed to active energy ray, and makes them combine by some effect or other.For example, this effect is attributable to extract hydrogen and activated carbon atom from the main chain of water-absorbing resin, the mutual bondings of carbon atom that make these contiguous existence, and the final reaction that forms cross-linked structure at random.

It is because this initiator can be dispersed on the good water-absorbing resin surface of hydrophilic and water absorbing properties easily that the present invention particularly points out " water-soluble radical polymerization initiator ".Therefore, might produce water-absorbing resin good aspect water absorbing properties.

Be used for water-soluble radical polymerization initiator of the present invention and have at water (25 ℃) and be not less than 1% weight, perhaps be not less than 5% weight, perhaps be not less than the dissolubility of 10% weight.The instantiation of the water-soluble radical polymerization initiator that should describe can be quoted persulfate such as Ammonium persulfate., sodium peroxydisulfate and potassium peroxydisulfate in response; Hydrogen peroxide; With water-soluble azo compounds as 2,2 '-azo two-2-amidine propane dihydrochloride and 2,2 '-azo two [2-2 (imidazoline-2-yl) propane] dihydrochloride.Among them, use the persulfate proof especially favourable, because the water-absorbing resin of modification is good in the withstand voltage absorbability of normal saline (abbreviating " withstand voltage absorbability " in this manual as), saline flow conductivity and the performance of normal saline free swell degree (abbreviating in this manual, " free swell degree " as) aspect.

Based on the water-absorbing resin of 100 parts of weight, the amount of water-soluble radical polymerization initiator can be in the scope of 0.01 to 20 part of weight, perhaps in the scope of 0.1 to 15 part of weight, perhaps in the scope of 1 to 10 part of weight.If 0.01 part of weight of the quantity not sufficient of blended water-soluble radical polymerization initiator, actively can also can stop water-absorbing resin to be modified by ray even then should deficiency may cause being exposed to.Conversely, if the amount of blended water-soluble radical polymerization initiator surpasses 20 parts of weight, the then reduction of the water absorbing properties of this excessive water-absorbing resin that may cause modification.

Definitely there is not the situation of water-soluble radical polymerization initiator to compare with use, for example when using oil-soluble radical initiator (especially oil-soluble photochemical polymerization initiator) alone, the present invention can realize that by basic use water-soluble radical polymerization initiator the production of water-absorbing resin has excellent performance.Incidentally, term used herein " oil-soluble photochemical polymerization initiator " is meant water is for example shown chemical compound less than the dissolubility of 1% weight.

Although the present invention uses the water-soluble radical polymerization initiator of selecting substantially in persulfate, hydrogen peroxide and water-soluble azo compounds, also can use the initiator that is different from water-soluble radical polymerization initiator in addition.Instantiation as other polymerization initiator that can use in addition as mentioned above, can quote photochemical polymerization initiator such as oil-soluble benzoin derivatives, benzyl derivative and acetophenone derivs and oil-soluble organic peroxide such as oil-soluble ketone peroxide, ketal peroxide, hydroperoxides, dialkyl peroxide, peroxy esters and peroxycarbonates.These photochemical polymerization initiators can be the commercially available prod, for example the product sold with trade (brand) name Irgacure 184 (hydroxy-cyclohexyl phenyl-ketone) and Irgacure 2959 (1-[4-(2-hydroxyl-oxethyl)-phenyl]-2-hydroxy-2-methyl-1-acetone) of Ciba Specialty Chemicals.

When the present invention must in addition use other initiator, based on the water-absorbing resin of 100 parts of weight, the amount of used initiator should be in the scope of 0 to 20 part of weight, perhaps in the scope of 0 to 15 part of weight, perhaps even in the scope of 0 to 10 part of weight.The amount that this usage rate correspondence is more less than water-soluble radical polymerization initiator, for example be no more than water-soluble radical polymerization initiator weight rate 1/2, even surpass 1/10, especially be no more than 1/50.

(c) thermal degradation radical polymerization initiator

According to the present invention, found that the radical polymerization initiator that has 10 hour concrete half-life decomposition temperature in the thermal degradation radical polymerization initiator can show and those similar effects that realize with above-mentioned water-soluble radical polymerization initiator.Term used herein " thermal degradation radical polymerization initiator " is meant the chemical compound that produces free radical by heating.Thermal degradation radical polymerization initiator with 10 hour half-life decomposition temperature in 0 ℃ to 120 ℃ or 20 ℃ to 100 ℃ scopes can be used among the present invention.Consider with active temperature during can roentgenization, but the radical polymerization initiator with thermal degradation of 10 hour half-life decomposition temperature in 40 ℃ to 80 ℃ scopes especially is preferred among the present invention.If the lower limit of 10 hour half-life decomposition temperature is less than 0 ℃, but then the radical polymerization initiator of thermal degradation is too unstable at memory period.Conversely, if its upper limit surpasses 120 ℃, then the chemical stability of thermal degradation radical polymerization initiator may be too high and causes the reactivity that reduces.

The thermal degradation radical polymerization initiator has than advantages of being cheap.In addition, the method and apparatus that is used for its production can be simplified because with compare as the commercially available chemical compound of light degradation radical polymerization initiator, it does not always need strict light shield.As the exemplary embodiments of thermal degradation radical polymerization initiator, can quote persulfate such as sodium peroxydisulfate, Ammonium persulfate. and potassium peroxydisulfate; Percarbonate such as SODIUM PERCARBONATE; Peracetic acid salt such as peracetic acid and peracetic acid sodium; Hydrogen peroxide; With azo-compound as 2,2 '-azo two (2-amidine propane) dihydrochloride, 2,2 '-azo two [2-2 (imidazoline-2-yl) propane] dihydrochloride and 2,2 '-azo two (2-methyl propionitrile).In thermal degradation radical polymerization initiator cited above, can use persulfate (comprising sodium peroxydisulfate, Ammonium persulfate. and potassium peroxydisulfate) and azo-compound (to comprise 2 with 10 hour half-life decomposition temperature in 40 to 80 ℃ of scopes, 2 '-azo two (2-amidine propane) dihydrochloride, 2,2 '-azo two [2-2 (imidazoline-2-yl) propane] dihydrochloride and 2,2 '-azo two (2-methyl propionitrile)).Because the remarkable withstand voltage absorbability of normal saline, saline flow conductivity and free swell degree can especially use persulfate.

The method of water-absorbing resin that production is used for the modification of absorption component of the present invention comprises heat of mixing degraded radical polymerization initiator and water-absorbing resin and does not add ethylenically unsaturated monomers.Up to now, the surface-crosslinked of water-absorbing resin generally realized by mixing surface crosslinking agent.Mix surface crosslinking agent and cause surface crosslinking agent and be present in strong chemical bonding between the functional group on the resin surface, and therefore in resin surface, introduced stable surface-crosslinked structure.Then, by the chain length of suitable selection surface crosslinking agent, might conveniently adjust the distance between crosslinked.The amount of the surface crosslinking agent that mixes by adjustment, crosslink density can be controlled.Yet the present invention has proved that the modification (being to introduce cross-linked structure to the surface of water-absorbing resin specifically) of water-absorbing resin can be only by adopting the thermal degradation radical polymerization initiator to need not to mix above-mentioned surface crosslinking agent.It is to prevent thermal degradation radical initiator and ethylenically unsaturated monomers reaction that the present invention utilizes the statement purpose of " not adding ethylenically unsaturated monomers ", thereby avoids by absorbing the consumption that activates the thermal degradation radical polymerization initiator that causes on the resin surface before the effect with active energy roentgenization.

In the present invention, although it is also unclear with the reason of the surface-crosslinked formation of active energy ray by the thermal degradation radical polymerization initiator, even but it is believed that the fact that cross-linked structure forms under the situation that lacks cross-linking compounds is because the thermal degradation radical polymerization initiator activates by being exposed to active energy ray, it acts on the several sections that is present in lip-deep main chain of water-absorbing resin or side chain, and makes them combine by some effect or other.For example, this effect is attributable to extract hydrogen from the main chain of water-absorbing resin and activated carbon is former gives the mutual bondings of carbon atom that make these contiguous existence, and the final reaction that forms cross-linked structure at random.

By the polymerization initiator that will have 10 hour concrete half-life decomposition temperature add to use then on the water-absorbing resin active can roentgenization gained mixture, carry out in the surface-crosslinked short time period at low temperatures, and the water-absorbing resin of gained modification can demonstrate high-gel strength and good water absorbing properties.Being used for thermal degradation radical polymerization initiator of the present invention can be oil-soluble or water miscible.With comparing of water solublity thermal degradation radical polymerization initiator, the composition ratio of oil-soluble thermal degradation radical polymerization initiator is not too responsive to pH and ionic strength.Yet, consider that the permeability to water-absorbing resin more preferably adopts water solublity thermal degradation radical polymerization initiator, this is because water-absorbing resin is hydrophilic.

Based on the water-absorbing resin of 100 parts of weight, the amount of thermal degradation radical polymerization initiator can be in the scope of 0.01 to 20 part of weight, perhaps can be in the scope of 0.1 to 15 part of weight, perhaps even can be in the scope of 1 to 10 part of weight.If the amount of blended thermal degradation radical polymerization initiator is lower than 0.01 part of weight, actively can also can stop water-absorbing resin to be modified by ray even then should deficiency may cause being exposed to.Conversely, if the amount of blended thermal degradation radical polymerization initiator surpasses 20 parts of weight, the then reduction of the water absorbing properties of this excessive water-absorbing resin that may cause modification.

According to second aspect of the present invention, can use the thermal degradation radical polymerization initiator that comprises persulfate, hydrogen peroxide and azo-compound.In this case, use capable of being combined has two or more persulfates of different counter ion counterionsl gegenions, and also can use persulfate separately.In addition, can use the initiator that is different from the thermal degradation radical polymerization initiator in addition.As the representative instance of other initiator used herein, can quote photochemical polymerization initiator such as oil-soluble benzoin derivatives, benzyl derivative and acetophenone derivs.Can use commercially available photochemical polymerization initiator, and this photochemical polymerization initiator comprises the product that Ciba Specialty Chemicals sells with trade (brand) name Irgacure 184 (hydroxy-cyclohexyl-phenyl ketone) and Irgacure 2959 (1-[4-(2-hydroxyl-oxethyl)-phenyl]-2-hydroxy-2-methyl-1-acetone).

If use other initiator in addition, based on the water-absorbing resin of 100 parts of weight, the amount of used initiator should be in 0 to 20 part scope, perhaps in 0 to 15 part scope, perhaps even in 0 to 10 part scope.This measures corresponding more less than thermal degradation radical polymerization initiator amount, for example is no more than the  of the weight rate of thermal degradation radical polymerization initiator, even surpasses 1/10, especially is no more than 1/50.

(d) water-absorbing resin and water-soluble radical polymerization initiator or thermal degradation radical polymerization initiator mixes

In this manual, phrase " water-soluble radical polymerization initiator or thermal degradation radical polymerization initiator " can abbreviate " radical polymerization initiator " as.

Although above-mentioned radical polymerization initiator can be realized by mixing with blended radical polymerization initiator of its unmodified form and water-absorbing resin with mixing of water-absorbing resin, also can realize by initiator being dissolved in then obtained aqueous solution is mixed with water-absorbing resin in the aqueous solution.Because water-absorbing resin can absorb moisture, be dissolved in radical polymerization initiator in the aqueous solution and provide the step of obtained aqueous solution that radical polymerization initiator is dispersed on the surface of water-absorbing resin and with the water-absorbing resin uniform mixing.Except water, aqueous solution also can comprise some other solvents, and the content of other solvent should weaken the dissolubility of radical polymerization initiator.

Based on the water-absorbing resin of 100 parts of weight (being reduced to the solids content of 100% weight), the amount of used aqueous solution is in the scope of 1 to 20 part of weight.If 1 part of weight of the quantity not sufficient of aqueous solution was even then should deficiency may cause also can stoping surface-crosslinked can not finely the realization when radical polymerization initiator is exposed to activity energy ray.Conversely, if the amount of aqueous solution surpasses 20 parts of weight, then should be excessive will be in the drying steps that forces after being exposed to active energy ray be in a disadvantageous position aspect the consumption of excessive power.This excessive water-absorbing resin that may cause is degraded.Aqueous solution can be used for dissolving radical polymerization initiator.After radical polymerization initiator and water-absorbing resin mixed, the gained mixture can mix with the ratio in above-mentioned scope with water or aqueous solution.Equally, being dried to the cross-linked hydrogel that water content obtains then by the polymerization single polymerization monomer component in 0 to 20% weight range can directly mix with radical polymerization initiator.

In order to improve the mixed nature of aqueous solution and water-absorbing resin, can add the mixed aid except water.Be not particularly limited although add the time of mixed aid, mixed aid can with the blended step a) while of water-absorbing resin and radical polymerization initiator or before step a), add.Therefore, the preferred embodiments of the invention provide the method for the water-absorbing resin of production modification, it comprises a) mixed water-absorbent resin and persulfate and does not add ethylenically unsaturated monomers, b) with step a) simultaneously or before step a), add the mixed aid that is different from water, and c) with active can roentgenization gained mixture.In addition, the preferred embodiment of the present invention provides the method for the water-absorbing resin of production modification, it comprises a) mixed water-absorbent resin and persulfate and does not add ethylenically unsaturated monomers, b) with step a) simultaneously or before step a), add the mixed aid that is different from water, and c) with active energy roentgenization gained mixture, wherein said water-absorbing resin has acidic-group and the neutralization ratio in 50% to 75% molar range (mole percent of neutral acidic-group in whole acidic-groups).

The mixed aid that is different from water is not particularly limited, as long as it is that water solublity or water can decentralized compounds except ethylenically unsaturated monomers or radical polymerization initiator, and it can suppress the agglomeration of water-absorbing resin and water, and improves mixing of aqueous solution and water-absorbing resin.Mixed aid can be water solublity or water can decentralized compound.Can decentralized compound as this water solublity or water, can typically use surfactant, water-soluble polymer, hydrophilic organic solvent, water-soluble inorganic compound, mineral acid, inorganic acid salt, organic acid and acylate.In this manual, term " water soluble compound " is meant in the water of 100g at room temperature to have the 1g of being not less than, and perhaps is not less than the chemical compound of 10g dissolubility.Because the interpolation of mixed aid can suppress the agglomeration of water-absorbing resin and water, and impel the uniform mixing of aqueous solution and water-absorbing resin, activity when shining in later step can shine on the water-absorbing resin by ray on an equal basis equably, thereby the uniform outer surface that can obtain whole water-absorbing resins is crosslinked.

The form of used mixed aid is not particularly limited, and it can the powder-form utilization, perhaps solubilized, be dispersed or suspended in the solution.It can aqueous solution the form utilization.

In addition, the interpolation of mixed aid order also is not particularly limited.Can adopt any method, as comprise and add in the water-absorbing resin mixed aid in this mixture, add and stir aqueous solution then method, and comprise mixed aid is dissolved in and make gained solution and the blended method of water-absorbing resin in the aqueous solution simultaneously.

As surfactant used herein, can adopt to have at least a surfactant that is selected from the group of forming by non-ionic surface active agent or anion surfactant that is not less than 7 HLB.As the instantiation of this surfactant, can quote sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyglyceryl fatty acid ester, polyoxyethylene alkyl ether, polyethenoxy alkylphenols, polyoxyethylene acyl ester, sucrose fatty acid ester, higher alcohol sulfate, alkylnaphthalene sulfonate, alkyl polyoxyethylene sulfuric ester and dialkyl sulfosuccinates.In these surfactants, can use polyoxyethylene alkyl ether.The number-average molecular weight of polyoxyethylene alkyl ether should be in 200 to 100,000 scope, perhaps in 500 to 10,000 scope.If number-average molecular weight is too big, then dissolubility reduces in the water, thereby owing to surfactant concentrations in the solution can not increase the poor efficiency that becomes that mixes that makes with water-absorbing resin, and the viscosity of solution also increases.Conversely, if number-average molecular weight is too little, then surfactant is as the mixed aid poor efficiency that becomes.

As the instantiation of water-soluble polymer, can quote polyvinyl alcohol, poly(ethylene oxide), Polyethylene Glycol, polypropylene glycol, polyacrylamide, polyacrylic acid, sodium polyacrylate, polymine, methylcellulose, carboxymethyl cellulose, hydroxyethyl-cellulose, hydroxypropyl cellulose, dextrin, sodium alginate and starch.In these polymer, can use Polyethylene Glycol.The number-average molecular weight of Polyethylene Glycol is similar to polyoxyethylene alkyl ether should be in 200 to 100,000 scope, perhaps in 500 to 10,000 scope.

As the instantiation of hydrophilic organic solvent, can quote alcohol as methanol, ethanol, propanol, isopropyl alcohol, butanols, isobutanol and the tert-butyl alcohol; Ketone such as acetone and methyl ethyl ketone; Ether such as dioxane, alkoxyl (gathering) ethylene glycol and oxolane; Amide as

-caprolactam and N, dinethylformamide; Sulfoxide such as dimethyl sulfoxide; Polyhydric alcohol such as ethylene glycol, diethylene glycol, propylene glycol, 2,2'-ethylenedioxybis(ethanol)., tetraethylene glycol (TEG), l, ammediol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, glycerol, 2-butylene-1,4-glycol, l, 3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,2-Hexalin, trimethylolpropane, diethanolamine, triethanolamine, polyoxypropylene, tetramethylolmethane and sorbitol.These hydrophilic organic solvents can use separately or use with two or more mixture of ingredients forms.

Instantiation as water-soluble inorganic compound, can quote alkali metal salt such as sodium chloride, sodium bisulfate and sodium sulfate, ammonium salt such as ammonium chloride, ammonium hydrogen sulfate and ammonium sulfate, alkali metal hydroxide such as sodium hydroxide and potassium hydroxide, polyvalent metal such as aluminum chloride, aluminium polychlorid, aluminum sulfate, potassium alum, calcium chloride, alkoxytitanium, zirconium carbonate ammonium, zirconium acetate and non-reduced alkali metal salt pH buffer agent such as bicarbonate, dihydric phosphate and dibasic alkaliine.

In addition,, can quote hydrochloric acid, sulphuric acid, phosphoric acid, carbonic acid and boric acid and salt thereof, for example their alkali metal salt and their alkali salt as the instantiation of mineral acid (salt).As the instantiation of organic acid (salt), can typically quote acetic acid, propanoic acid, lactic acid, citric acid, succinic acid, malic acid and tartaric acid and salt thereof, for example their alkali metal salt and their alkali salt.

In the above chemical compound of quoting, at least a water solublity or the water that are selected from the group of being made up of following material can be used as mixed aid by decentralized compound: polyoxyethylene alkyl ether, Polyethylene Glycol, water solublity polyvalent metal, sodium chloride, ammonium hydrogen sulfate, ammonium sulfate, sulphuric acid and hydrochloric acid.

These mixed aids can use separately or use with the mixed form of two or more compositions.As mentioned above, add mixed aid amount be not particularly limited, as long as it suppresses the gathering of water-absorbing resin and water, and improve mixing of aqueous solution and water-absorbing resin.Typically, the addition of mixed aid is with respect to 100 parts water-absorbing resin by weight in 0.01 to 40 part scope by weight or by weight in 0.1 to 5 part the scope.Alternatively, in the present invention, mixed aid can the aqueous solution form utilizes, and based on the total amount of aqueous solution, its concentration is in the scope of 0 to 40% weight, perhaps in the scope of 0.01 to 30% weight, perhaps even in the scope of 0.1 to l 0% weight.

Method as for mixed water-absorbent resin and radical polymerization initiator, can quote by using common agitating device to realize blended method as an example, common agitating device for example comprises V-type agitator, banding pattern agitator, spiral type stirrer, rotating disk type agitator, airflow agitator, intermittently kneading and cutting machine, kneading and cutting machine, oar type agitator or spatial mode agitator continuously.

(e) active energy ray

In the production of water-absorbing resin, polymerization rate is well-known by being exposed to the active fact that can ray improves.For example, by with polymerizable monomer component and internal crosslinking agent and the photochemical polymerization initiator mixes and with active can ray such as ultraviolet, electron radiation or radiation gamma gained mixture, might prepare insoluble water-absorbing resin with internal crosslinking.Therefore, as the method on crosslinked water-absorbing resin surface, by using surface crosslinking agent and promoting relevantly to react obtained surface-crosslinked and form known to the public by applying heat.Surface-crosslinked for water-absorbing resin can be used the chemical compound such as polyhydric alcohol, multivalence glycidyl ether, halogenation epoxide and the multivalence aldehyde that have a plurality of functional groups in molecular cell.Usually, by 100 to 300 ℃ of time heating, these functional groups can be present in the lip-deep carboxyl reaction of water-absorbing resin and on the water-absorbing resin surface, produce cross-linked structure.Yet, might on the surface of water-absorbing resin, form cross-linked structure by using radical polymerization initiator and being exposed to active energy ray, and need not the existence of this surface crosslinking agent and polymerisable monomer according to the present invention.By method disclosed herein, also might improve the withstand voltage absorbability (AAP) and the saline flow conductivity (SFC) of the water-absorbing resin of modification.

In this article, active irradiation that can ray can be during water-absorbing resin and radical polymerization initiator mixed process or carry out after the mixing of this two kinds of components.Yet,, preferably adopt the mixture that comprises the aqueous solution for preparing water-absorbing resin and comprise water-soluble radical polymerization initiator also to use the method for active energy roentgenization gained mixture from the crosslinked angle consideration of formation uniform outer surface.

As the instantiation of active energy ray, can quote ultraviolet, electron radiation and gamma-rays.These are active can rays can to use separately or use with the combining form of two or more compositions.In these active energy rays, ultraviolet and electron radiation prove favourable.Consider active can ray to the influence of human body, ultraviolet proves preferably, and ultraviolet have the wavelength that is no more than 300nm also can be in 180 to 290nm scope.

As for illuminate condition, when adopting ultraviolet, exposure rate can be 3 to 1000mW/cm ²Scope in, and dosage 100 to 10000mJ/cm ²Scope in.As the instantiation of the device that is used for irradiation ultraviolet radiation, can quote high-pressure mercury gas lamp, low-pressure mercury gas lamp, metal halide lamp, xenon lamp and Halogen light.As long as adopt ultraviolet, for example wavelength is no more than the ultraviolet of 300nm, and then it can comprise other radiation and wavelength and step and is not particularly limited.When adopting electron radiation, for example accelerating potential is in 50 to 800kV scope, and absorbed dose are in the scope of 1 to 1000kGy (0.1 to 100Mrad).

Usually, active persistent period that can roentgenization can be no less than 0.1 minute but is less than 60 minutes, perhaps is no less than 0.2 minute but is less than 30 minutes, perhaps even is not less than 1 minute but is less than 15 minutes.When adopting conventional surface crosslinking agent, this persistent period may be above 60 minutes.Be the crosslink density that is fixed, the present invention can reduce the persistent period of surface-crosslinked processing.

When surface treatment when realizing, does not then need to apply heat by active irradiation that can ray.Yet the irradiation of active energy ray may cause photothermal generation.Usually, it is enough to be no more than 150 ℃, perhaps is no more than 120 ℃, perhaps even in the scope of room temperature to 100 ℃, perhaps even under the temperature in 50 to 100 ℃ of scopes handles water-absorbing resin.Therefore, the invention enables treatment temperature to be set in than the lower level of conventional surface treatment temperature.

During active energy roentgenization, water-absorbing resin should keep stirring.Stir by this, might use the mixture of active energy ray uniform irradiation radical polymerization initiator and water-absorbing resin.As the instantiation that is used for stirring the device of water-absorbing resin during can roentgenization, can quote and shake agitator, shake feed appliance, banding pattern agitator, circular cone banding pattern agitator, spiral type stirrer, airflow agitator, intermittently kneading and cutting machine, kneading and cutting machine, oar type agitator, high speed fluidization agitator and buoyancy fluidization agitator continuously active.

Usually the known free radical that comprises can be subjected to the inhibition of oxygen as the reaction of active substance.Yet in production method disclosed herein, when oxygen was present in the system, its solid-state properties of surface-treated water-absorbing resin can not weaken.Infer between the light period of active energy ray that by this fact being used for needn't be for inert around the atmosphere of reaction system.

(f) other processing

With active can roentgenization after, water-absorbing resin randomly under the temperature in 50 ℃ to 250 ℃ scopes through heat-treated to carry out drying.

In addition, after with active energy roentgenization, it is surface-crosslinked to use the known surface crosslinking agent of any routine (as polyhydric alcohol, epoxide and alkylene carbonate) to give water-absorbing resin.

Be used in the method for water-absorbing resin of modification of absorption component of the present invention in production, for active can roentgenization before or the flowability of enhance fluid after the irradiation or between the light period, water-absorbing resin can add a kind of reagent.As the instantiation of fluidity enhancers, can quote mineral such as Talcum, Kaolin, bleaching earth, bentonite, activated clay, barite, bitumen, strontium stone, ilmenite and pearlite; Aluminium compound such as aluminum sulfate 14 to 18 hydrates (or anhydride), aluminium potassium sulfate 12 hydrates, aluminum sodium sulfate 12 hydrates, aluminum chloride, aluminium polychlorid and aluminium oxide and their aqueous solution; Other multivalent metal salt; Hydrophilic amorphous silicas (dry method product of for example making and sell with trade (brand) name " Reolosil QS-20 " and the sedimentation method product of making by DEGUSSA Corp. and sell with trade (brand) name " Sipernat 22S and Sipernat 2200 ") by Tokuyama K.K.; And composite oxides such as silica alumina magnesium oxide complex (for example by ENGELHARDCorp. with trade (brand) name " Attagel#50 " product of sale), complex and the silicon oxide and the magnesian complex of silicon oxide and aluminium oxide.May be in the scope of 0 to 20 part of weight, perhaps in the scope of 0.01 to 10 part of weight, perhaps in addition this fluidity enhancers in the scope of 0.1 to 5 part of weight mix with the water-absorbing resin of the modification of 100 parts of weight.Fluidity enhancers can the form with aqueous solution be added when it is dissolved in water, and the form with powder or serosity when it does not dissolve is added.Fluidity enhancers can be added with the blended form of radical polymerization initiator.Other additive (as antibacterial, deodorizer and chelating agen) can suitably use in addition in the amount in the above-mentioned scope.

(g) water-absorbing resin of modification

When the method for water-absorbing resin that implement to produce the modification that is used for absorption component of the present invention, the water-absorbing resin of being produced obtains the withstand voltage absorbability of its improvement.The crosslinked formation of known surface up to now causes the free wxpansion degree that reduces a little, but has improved even the ability of the liquid hold-up when pressurized state promptly withstand voltage absorbability.By method disclosed herein, to compare with the withstand voltage absorbability of modification resin before, the withstand voltage absorbability of the 4.83kPa of water-absorbing resin is enhanced and is not less than 1g/g.It is believed that this fact shows that the inventive method introduced cross-linked structure to the surface of water-absorbing resin.As the performance after the modification, this improvement can be not less than 8g/g, perhaps is not less than 12g/g, perhaps is not less than 15g/g, perhaps is not less than 20g/g, perhaps not even less than 22g/g.The water-absorbing resin that is used for the modification of absorption component of the present invention shows the withstand voltage absorbability with the 4.83kPa in 8 to 40g/g scopes.Although the absorbefacient upper limit that this is withstand voltage is not crucial especially, and is when considering that the cost that causes owing to the production difficulty raises, provable enough near the 40g/g.

Then, free swell degree (GV) can be not less than 8g/g, perhaps is not less than 15g/g, perhaps is not less than 20g/g, perhaps not even less than 25g/g.Although the upper limit is not specially limited, it should be no more than 50g/g, perhaps is no more than 40g/g, does not perhaps even surpass 35g/g.If the not enough 8g/g of free swell degree (GV), then water-absorbing resin will be not suitable as hygienic material such as disposable diaper owing to crossing a spot of absorption.Conversely, if free swell degree (GV) surpasses 50g/g, this is excessive may to stop the water-absorbing resin of production because the shortage of gel strength obtains the fluidic ability of transmission of brilliance.

The water-absorbing resin of the modification that obtains by method disclosed herein has following performance: saline flow conductivity (SFC) is not less than 10 (* 10 ^-7Cm ³Sg ^-1), perhaps be not less than 30 (* 10 ^-7Cm ³Sg ^-1), perhaps be not less than 50 (* 10 ^-7Cm ³Sg ^-1), perhaps not even less than 70 (* 10 ^-7Cm ³Sg ^-1), perhaps not even less than 100 (* 10 ^-7Cm ³Sg ^-1).These numerical value are measured by appointed method in the working example of hereinafter quoting.

In addition, the water-absorbing resin of the modification that obtains by method disclosed herein has very low residual monomer content.It is believed that this is because initiator free radical and the reaction of the residual monomer in the water-absorbing resin by generating with the ultraviolet radiation radical polymerization initiator.Because water-absorbing resin is used for disposable diaper, therefore in view of abnormal smells from the patient and safety, remaining content of monomer should be as far as possible little.Although usually in 200 to 500ppm scope, the residual monomer content major part of the surface-treated water-absorbing resin that obtains by the present invention is no more than 200ppm (being limited to 0ppm down) as the residual monomer content of the water-absorbing resin of matrix polymer.The residual monomer content of the water-absorbing resin of modification can be no more than 200ppm, perhaps is no more than 150ppm, perhaps is no more than 100ppm (being limited to 0ppm down).

In addition, the water-absorbing resin of the modification that obtains with method of modifying by routine is compared, the water-absorbing resin of the modification that obtains by method disclosed herein has few solids content, and conventional method of modifying comprises to water-absorbing resin and adds surface conditioning agent as matrix polymer and heating blends at high temperature.This is because according to method disclosed herein, and reaction does not need high temperature, still keeps after reaction even therefore be included in the most of water that adds in the aqueous solution on the water-absorbing resin as matrix polymer.Big water content has following effect in the water-absorbing resin: can reduce and have the fine powder amount (considering that for health this fine powder is worthless) that is no more than 150 μ m granularities, can prevent to cause during air conveying generation of static electricity on the particle surface of obstruction, and can suppress air conveying during because the degeneration of the physical attribute that physical hazard causes.The solids content of the water-absorbing resin of modification can be no more than 95%, perhaps is no more than 93%, perhaps is no more than 91%.Although lower limit is not crucial, being no more than 70% solids content might be inadvisable in some uses, because in this case, the absorbability of Unit Weight water-absorbing resin reduces.

Therefore, the present invention relates to be used for absorption component and have the water-absorbing resin of the powdered modification that the monomer component of the acrylic acid (salt) as key component obtains, it is characterized in that having (i) and be not less than 40 (10 by polymerization ^-7Cm ³Sg ^-1) mobile conductivity, (ii) be no more than 95% solids content and (iii) be no more than the residual monomer content of 150ppm.In this case, the water-absorbing resin of modification can have the withstand voltage absorbability of normal saline of normal saline free swell degree that is not less than 25g/g and/or the 4.83kPa that is not less than about 22g/g.These numerical value are measured by appointed method in the working example of hereinafter quoting.

The form of the surface-treated water-absorbing resin that obtains by method disclosed herein can suitably be adjusted by treatment conditions, as the form of water-absorbing resin before handling and the agglomeration and the molding of the processing water-absorbing resin after handling.Yet the water-absorbing resin of modification has powder-form usually.This powder has in 10 to 1,000 mu m ranges or the weight average particle diameter in 200 to 600 mu m ranges (specifying by screen sizing).In this powder, based on the weight of water-absorbing resin, having the granule content of 150 to 850 μ m diameters can be in 90% to 100% scope by weight or in 95% to 100% scope by weight.

Production method disclosed herein demonstrates the effect of agglomeration at the fine powder of the production period generation of the water-absorbing resin of modification during the process of surface-crosslinked water-absorbing resin.Therefore, even when water-absorbing resin comprised fine powder once in a while before modification, the fine powder that the method for the water-absorbing resin that is used for the production modification disclosed herein can agglomeration comprises, thus reduce fine powder content in the water-absorbing resin of the modification that is included in gained.Compare the higher granularity of particle size distribution deflection of the water-absorbing resin of the modification of being produced with the water-absorbing resin before the modification.Yet, degrees of offset along with the kind and the changes of contents of the blended radical polymerization initiator of water-absorbing resin, and when it adds as aqueous solution, also along with water content, active illuminate condition and the fluidizing method between the light period that can ray change.

The water-absorbing resin of the modification that obtains by method disclosed herein have on the whole surface of water-absorbing resin with high density evenly form surface-crosslinked, and can expectation the characteristic that water-absorbing resin had be increased to very high level such as absorptive capacity, infiltration rate, gel strength and suction force.When the water-absorbing resin of acrylic-type being carried out finding that surface-crosslinked speed and degree depend on neutralization ratio when surface-crosslinked by using such as the surface crosslinking agent of polyhydric alcohol, multivalence epoxide or alkylene carbonate.Specifically, when in and ratio is surface-crosslinked when low carries out fast, and when in and ratio is surface-crosslinked when high is not easy realization.For the surface-crosslinked water-absorbing resin that obtains by post neutralization, post neutralization need evenly carry out after surface-crosslinked processing.Yet the present invention can and produce the good water-absorbing resin of water absorption to the water-absorbing resin modification, and need not to depend on the uniformity of the neutralization ratio or the post neutralization of water-absorbing resin.Therefore the surface-crosslinked according to inferring effect of depending on radical polymerization initiator to the water-absorbing resin main chain can go on and whether continues with carboxyl that form with acid exists or to have reduced salify irrelevant.

When method disclosed herein was carried out in the presence of ethylenically unsaturated monomers, this implementation did not meet target of the present invention, because radical polymerization initiator can consume owing to the polyreaction of ethylenically unsaturated monomers.

According to the present invention, even the surface treatment of water-absorbing resin is also made us very realizing satisfactorily under near the reaction temperature the room temperature, and the surface-treated water-absorbing resin that obtains subsequently can demonstrate the expectation characteristic such as absorptive capacity, infiltration rate, gel strength and suction force that water-absorbing resin was had with high level.Therefore, the water-absorbing resin that obtains by method disclosed herein most desirably is applicable to cotton wool, disposable diaper and other hygienic material that is used for absorb body fluids and is used for rural activity.

Disposable diaper

The water-absorbing resin of producing according to method disclosed herein is used for absorption component.These absorption components are included in the disposable diaper, and typically described absorption component is included in the absorbent cores.

Term used herein " diaper " is meant the absorbent article of being worn around lower body by baby and incontinent person usually." absorbent article " be meant and absorb and the device of receiving fluids, more particularly be meant be close to wearer's health or contiguous that place, be used to absorb and hold the multiple excremental device that discharges by health.

Comprise so-called belt-diapers according to term of the present invention " diaper ", promptly by utilizing fastening system such as adhesive tape or machinery band to connect and being fixed to wearer (preferred baby or less than 5 years old child) diaper on one's body.Also comprise pull-on diaper and training pants according to term of the present invention " diaper ", promptly have the closed side and as conventional underwear through wearer's diaper on one's body.Term " diaper " also comprises any combination between the mentioned types of diapers.

Be particularly useful for disposable diaper of the present invention and typically comprise outer covering piece, described outer covering piece comprises the egative film of liquid permeable topsheet, preferred liquid impermeable and places absorbent cores between top flat and the egative film usually.Absorbent cores can comprise any absorbing material, this material is normally compressible, suitable shape, non-stimulated to wearer's skin, and can absorb and receiving fluids, as other body excretions of urine and some.Except water-absorbing resin of the present invention, absorbent cores also can comprise the multiple liquid absorption material that is usually used in disposable diaper and other absorbent article, as is commonly called the wood pulp of the pulverizing of airfelt.

Absorbent cores typically comprises at least one fluid acquisition layer and at least one fluid storage layer.Fluid acquisition layer is typically towards top flat, and the fluid storage layer is typically towards diaper chassis.

As the exemplary absorbent structrual description that absorbs molectron in following patent: that authorized people such as Herron on August 11st, 1992 is entitled as " Absorbent Structure Containing Individualized; Polycarboxylic Acid Crosslinked Wood Pulp Cellulose Fibers " United States Patent (USP) 5,137,537; JIUYUE in 1992 were authorized people's such as Young the United States Patent (USP) 5,147,345 that is entitled as " High EfficiencyAbsorbent Articles For Incontinence Management " on the 15th; Authorized the United States Patent (USP) 5,342,338 that is entitled as " Disposable Absorbent Article ForLow-Viscosity Fecal Material " of Roe on August 30th, 1994; Authorized the United States Patent (USP) 5,260,345 that is entitled as " Absorbent Foam Materials For Aqueous Body Fluids andAbsorbent Articles Containing Such Materials " of DesMarais on November 9th, 1993; Authorize people's such as Dyer the United States Patent (USP) 5,387,207 that is entitled as " Thin-Until-Wet Absorbent Foam Materials ForAqueous Body Fluids And Process For Making Same " February 7 nineteen ninety-five; Authorize people's such as LaVon the United States Patent (USP) 5,397,316 that is entitled as " Slitted Absorbent Members ForAqueous Body Fluids Formed Of Expandable Absorbent Materials " March 14 nineteen ninety-five; And the United States Patent (USP) 5,625,222 that is entitled as " Absorbent Foam Materials ForAqueous Fluids Made From high In al. " on July 22nd, 1997.

In one embodiment of the invention, the water-absorbing resin of producing according to method disclosed herein is in the content by the weight at least 80% of described total fluid storage layer, perhaps with at least 85% content, perhaps with at least 90% or even surpass 95% content and be included in the fluid storage layer of absorbent cores.In order to utilize the water-absorbing resin of these higher concentrations, water-absorbing resin must satisfy some parameter area (such as the scope of withstand voltage absorbability and saline flow conductivity).Otherwise, so-called gel blockage will take place.

Absorb after the aqueous solution unmodified swelling water absorbing resin particle become very soft and easy deformation.After distortion, the void space between the water absorbing resin particle gets clogged, and this has just increased the flow resistance for liquid greatly.This is commonly called " gel blockage ".Under the gel blockage situation, liquid can only be crossed swollen water absorbing resin particle by diffusion flow, and this is than flowing slowly manyly in the space between water absorbing resin particle.

If absorption component comprises high-load water-absorbing resin and includes only a spot of other liquid absorption material (as cellulose fibre) that then the probability of gel blockage is very big.Therefore, water-absorbing resin must be modified, thereby also can avoid gel blockage even use high-load water-absorbing resin, and for example, water-absorbing resin must be modified to have higher SFC value and high withstand voltage absorption value.The water-absorbing resin that carries out modification according to method disclosed herein is modified, thereby allows and use high-load water-absorbing resin.

In order to increase the integrity of absorbent cores, this core can comprise the water-absorbing resin of making according to method disclosed herein, and described water-absorbing resin is embedded in the substrate of thermoplastic resin or in the substrate of hot-melt adhesive or in their mixture.

If the fluid storage layer comprise as this paper the water-absorbing resin of preferred high level, absorbent cores or at least the fluid storage layer can be wrapped in the so-called core wrap (for example non-woven material slice), described core wrap is wrapped in around the absorbent cores to prevent that water absorbing resin particle from being selected by absorbent cores.

Method and embodiment

Now, the present invention will more specifically describe with reference to working example and comparing embodiment following.The present invention is not limited thereto.Hereinafter, for simplicity, " parts by weight " can be expressed as " umber " simply, and " liter " can be reduced to " L ".Assay method and evaluation methodology pointed in working example and the comparing embodiment will be described as follows.

(1) particle size distribution

With the test sieve the given water-absorbing resin sample of ten grams before the surface treatment and after the surface treatment is classified, described test sieve has the mesh size (Iida Seisakusho K.K. manufacturing) of diameter and 850 μ m, 600 μ m, 300 μ m and the d150 μ m of 75mm.The weight of measuring classification part resin afterwards is to obtain the percetage by weight of each granularity.By making with Iida Seisakusho Ltd. and rocking sample with the sieve that trade (brand) name Sieve Shaker ES-65 sells and realized classification in five minutes.Dry 24 hours of decompression (less than 133.3Pa (1mmHg)) during at 60 ± 5 ℃ before being used for measuring with water-absorbing resin.

(2) mensuration of solids content

In that to measure the end directly be 4cm and highly be in the aluminum cup of 2cm, the sample of the given water-absorbing resin of 1g is evenly distributed on the lower surface of aluminum cup.Sample in the cup was placed three hours in being adjusted to 180 ℃ hot-air drier in advance.The solids content of water-absorbing resin (%) is calculated based on the loss in weight that takes place between resting period.

(3) free swell degree (GV)

The sample of the given water-absorbing resin of 0.2g evenly is positioned over (size: 60mm * 60mm in the pouch of supatex fabric; By Nangoku Pulp Kogyo K.K. make and with trade mark " Heatlon Paper, Model GSP-22 sells).The pouch that will have sample in room temperature (25 ± 2 ℃) down is immersed in the sodium-chloride water solution (normal saline) of 0.9% a large amount of weight.In solution, place after 30 minutes, pouch is pulled out and used whizzer under the centrifugal force of 250G, dewatered three minutes.Then, measure the weight W of pouch ₁(g).Repeat identical step under any water-absorbing resin not adopting, and measure the weight W of used pouch at that time ₂(g).Utilize W ₁And W ₂Calculate the free swell degree of sample according to following formula.

Free swell degree (g/g)=[W ₁(g)-W ₂(g)-weight (g) of water-absorbing resin]/weight (g) of water-absorbing resin.

(4) withstand voltage absorbability (AAP)

400 purpose stainless steel metal silk screens (mesh size is 38 μ m) are welded to the bottom that internal diameter is the plastic support cylinder of 60mm.Under the damp condition of room temperature (25 ± 2 ℃) and 50% relative humidity, the given water-absorbing resin of 0.900g is dispersed on the metal gauze, piston and load is mounted thereto in succession with mentioned order, adjust piston and load respectively evenly to apply the load of 4.83kPa to water-absorbing resin, suppose that external diameter is slightly less than 60mm, prevent to produce gap with respect to the inner wall surface of back-up roller, and make it possible to produce unimpeded moving both vertically, measure the gross weight Wa (g) of gained measuring device.

The glass filter of 90mm internal diameter (aperture: 100 to 120 μ m: made by Sogo RikagakuGlass Manufactory K.K.) is placed on the inside that diameter is the petri diss of 150mm, and the sodium-chloride water solution (normal saline) (20 ℃ to 25 ℃) of 0.9% weight is added in the petri diss is increased to the level identical with the upper surface of glass filter up to it.With diameter filter paper (the reservation particle diameter of the thickness of 0.26mm and 5 μ m that is 90mm; Make and sell by Advantec ToyoK.K. with ProductName " JIS P 3801, No.2 ") be placed on the normal saline so that make the whole moistenings in its surface and remove excess solution.

On the whole filter paper that is placed in moistening of gained measuring device, and make water-absorbing resin load absorbent solution reach the stipulated time.This soak time is set at from measurement begins to be calculated as one hour.Particularly, leave standstill after one hour and to promote entire measuring device and to measure its weight W _b(g).The mensuration of this weight must not be exposed under any vibration at device carries out as quickly as possible.Withstand voltage absorbability (AAP) (g/g) utilizes W _aAnd W _bCalculate according to following formula.

AAP (g/g)=[W _b(g)-W _a(g)]/weight (g) of water-absorbing resin

(5) saline flow conductivity (SFC)

Saline flow conductivity (SFC) is with showing that given water absorbing resin particle shows that the value of the penetration degree that has represents under to the wetting state of respective liquid.SFC is for along with the index that the permeability of liquid is increased proportional growth.

The mensuration of SFC by follow do the necessary world of revising not unexamined patent announce that the test of describing in the communique of HEI9-509591 that is used for saline flow conductivity (SFC) carries out.

By utilizing device shown in Figure 1, the granule (0.900g) of given water-absorbing resin evenly is positioned in the container 40, under 2.07kPa (0.3psi) pressure in artificial urine swelling 60 minutes, and the height of 44 layers of record gels.Next, under 2.07kPa (0.3psi) pressure, will from the saline 33 of 0.69% weight of jar 31 under the regulation hydrostatic pressure by swollen gel layer.This SFC test is carried out under room temperature (20 ℃ to 25 ℃).By means of computer and balance, the amount of liquid that will flow through gel layer in 20 seconds interval is recorded as 10 minutes time function.Flow rate F s (T) by swell gel 44 (mainly between adjacent particles) decides divided by the time (s) that increases by the weight (g) with increase, and unit is g/s.The time that wherein obtains fixed hydrostatic pressure and stable flow velocity is represented with Ts.The data that obtain during 10 minutes after Ts are specifically designed to the calculating flow velocity.By utilizing the flow velocity that obtains during 10 minutes after the Ts to calculate Fs (T=0) value, i.e. initial flow-rate by gel layer.The result of Fs (T=0) by the extrapolation least square method that carries out on to the time at Fs (T) calculates to T=0.

Saline flow conductivity (SFC)

＝(Fs(t＝0)×L0)/(ρ×A×ΔP)

＝(Fs(t＝0)×L0)/139506

Wherein Fs (t=0) represents the flow velocity with the g/s unit representation, the L0 representative height of the gel layer of cm unit representation, and ρ represents the density (1.003g/cm of NaCl solution ³), A represents the upside area (28.27cm of the gel layer in the pond 41 ²), Δ P representative is applied to hydrostatic pressure (492Pa (4920 dyne/cm on the gel layer ²), and the unit of SFC value is (10 ^-7Cm ³Sg ^-1).

In device shown in Figure 1, jars 31 have the glass tubing 32 that inserts in it, and the lower end of glass tubing 32 saline 33 that is set to make 0.69% weight can maintain the height of the bottom 5cm of the swell gel 44 that holds in the pond 41.The saline solution of 0.69% weight in the jar 31 supplies in the pond 41 by the L letter pipe 34 of being furnished with tap 35.Container 48 under pond 41 is used to collect the liquid that flows through, and this collection container 48 is arranged on the pan scale.Pond 41 has the internal diameter of 6cm.Stainless metal gauze (mesh size is 38 μ m) 42 is arranged on the lower surface of bottom, pond.Piston 46 has the hole 47 that is enough to flow through liquid in its underpart, and in its bottom glass filter 45 is installed, and this filter has good penetration, can prevent that the granule of water-absorbing resin or its swell gel from entering hole 47.Pond 41 is placed in the shelf that is used to install this pond.The stand surface that contacts this pond be placed on can not the stainless steel metal silk screen 43 of block liquid passage on.

By being added on, 0.25g calcium chloride dihydrate, 2.0g potassium chloride, 0.50g magnesium chloride hexahydrate, 2.0g sodium sulfate, 0.85g Ammonium biphosphate, 0.15g diammonium phosphate and 994.25g purified water obtain above-mentioned artificial urine together.

(6) can extract polymer

In having the capping plastic containers of 250mL internal volume (measure and be 6cm diameter * 9cm height), put into the sodium-chloride water solution of 0.900% weight of the independent weighing of 184.3g, the particulate water-absorbing resin of 1.00g is added on it, and by using magnetic stirring apparatus (measure and be 8mm diameter and 25mm length) under the speed of 52.4rad/s (500rpm), to stir 16 hours together with the solubilized content in the extracting resin.Make extract pass through a filter paper (the reservation particle diameter of the thickness of 0.26mm and 5 μ m; Make and sell by Advantec Toyo K.K. with ProductName " JIS P3801 No.2 "), the gained filtrate of 50.0g is used for measuring.

The sodium-chloride water solution of independent titration 0.900% weight of NaOH aqueous solution of at first using 0.1N is to pH 10, and the HCl aqueous solution titration of using 0.1N subsequently is to pH 2.7, to obtain fixed titer ([bNaOH] ml, [bHCl] ml).

By solution to be measured is carried out identical titration operation, can obtain titer ([NaOH] ml, [HCl] ml).

Under the water-absorbing resin situation of being made up of the acrylic acid and the sodium salt thereof of for example known quantity, the extracted polymer of this water-absorbing resin can calculate according to following formula based on the titer that is obtained by monomeric mean molecule quantity and aforesaid operations.When equivalent is unknown, the neutralization ratio calculating that monomeric mean molecule quantity obtains by using titration.

Can extract polymer (% weight)=0.1 * (mean molecule quantity) * 184.3 * 100 * ([HCl]-

[bHCl])/1000/1.0/50.0

Neutralization ratio (% mole)=[1-([NaOH]-[b (NaOH)])/([HCl]-[bHCl])] * 100

(7) residual monomer content

The water-absorbing resin of 0.500g is scattered in the deionized water of 1000mL.Dispersions obtained is that the magnetic stirrer 2 hours of 50mm is to extract residual monomer with length.Then, utilize filter (by Toyo Roshi Kaisha, Ltd., No.2 produce, keep granularity as defined by JIS P 3801 be 5 μ m) filter swell gel.Use the filter colour disk 25A of pretreatment HPLC sample (to produce water type, aperture: 0.45 μ m) further filter filtrate is used to measure residual monomer content with preparation sample by Kurabo Industries Ltd..Be used to measure sample high performance liquid chromatography (HPLC) analysis of residual monomer content.The following mensuration of the residual monomer content of water-absorbing resin: analyze 12 standard solution that comprise predetermined concentration monomer (acrylic acid) to obtain calibration curve, the use calibration curve is as external standard and consider dilution rate.The operating condition of HPLC is as follows.

Carrier solution: phosphate aqueous solution obtains in the ultra-pure water that can be by 3mL phosphoric acid (by weight 85%, produced superfine chemicals by WakoJunyaku Kabushiki Kaisha) being diluted in 1000mL (than resistance: be not less than 15M Ω cm).

Carrier flow velocity: 0.7mL/min

Pillar: SHODEX RSpak DM-614 (producing) by Showa Denko Kabushiki Kaisha

Column temperature: 23 ± 2 ℃

Wavelength: ultraviolet 205nm

Production instance 1

In kneading and cutting machine with two δ type blades, aqueous solution (the monomer concentration: 38% weight of the acrylates type that preparation is formed by sodium acrylate, acrylic acid and water, neutralization ratio: 75% mole), and will as the polyethyleneglycol diacrylate of internal crosslinking agent (average ethylene oxide unit number, n=8) with based on the ratio solvent of 0.05% mole of monomer in it.

Then, nitrogen is blown in this aqueous solution to reduce the oxygen concentration in the aqueous solution and to replace the entire reaction internal tank.Next, keep under the rotation at two δ type blades, with adding in the container of 0.05% mole (based on monomer) as the sodium peroxydisulfate of polymerization initiator and the L-ascorbic acid of 0.0006% mole (based on monomer), component in the stirring kneading and cutting machine and polymerization 40 minutes.Thereby the hydrogel shaped polymer that acquisition has the 2mm particle mean size.

The hydrogel shaped polymer that is obtained like this in being set at 170 ℃ hot-air drier dry 45 minutes.Then, dry polymer is pulverized in roller flour mill and carry out classification, have greater than the granule of the particle diameter of 850 μ m and obtain powdery water-absorbing resin (A) as matrix polymer to remove with sieve with 850 μ m mesh sizes.

With therefore as water-absorbing resin (A) that matrix polymer obtained with various performance classifications.The results are shown in the table 1.

Particle size distribution as the water-absorbing resin (A) that matrix polymer obtained is shown in Table 2.

Embodiment 1

In a separable quartz flask, 10g water-absorbing resin (A) put into as matrix polymer and stir with stirring vane, the ammonium persulfate aqueous solution with 23.8% weight of 1.05g adds in the matrix polymer of stirring then.Continue to stir after 15 minutes, what obtain subsequently stirs the mixture with ultraviolet with 60mW/cm ²Radiant intensity irradiation 10 minutes to obtain surface-treated water-absorbing resin (1), described ultraviolet is sent by the ultraviolet radiation device of being furnished with metal halide lamp (made and sold with product code UVL-1500M2-N1 by Ushio Denki K.K.) (made and sold with product code UV-152/IMNSC3-AA06 by identical company).Being used for surface-treated condition and water absorbing properties is shown in Table 3.

Embodiment 2

Surface-treated water-absorbing resin (2) obtains by the step of following among the embodiment 1, but uses the ammonium persulfate aqueous solution of 38.5% weight of 1.30g.

Embodiment 3

Surface-treated water-absorbing resin (3) obtains by the step of following among the embodiment 2, but changes into 5 minutes with the persistent period of ultraviolet radiation.

Embodiment 4

Surface-treated water-absorbing resin (4) obtains by the step of following among the embodiment 1, but uses the sodium persulfate aqueous solution of 38.5% weight of 1.30g.

Comparing embodiment 1

The surface-treated water-absorbing resin (1) that is used for comparison obtains by the step of following embodiment 2, but utilizes in 80 ℃ hot bath the position of ultraviolet radiation heating 10 minutes.

Production example 2

Gelatinous polymer obtains by the step of following in the production example 1, but the amount that will change internal crosslinking agent is to based on 0.065% mole of monomer.The hydrogel shaped polymer that is obtained like this in being set at 175 ℃ hot-air drier dry 50 minutes.Then, dry polymer pulverized with roller flour mill and carry out classification, have greater than the granule of the particle diameter of 500 μ m and have less than the granule of the particle diameter of 300 μ m and obtain water-absorbing resin (B) as matrix polymer to remove with sieve with 500 μ m mesh sizes and sieve with 300 μ m mesh sizes.

With therefore as water-absorbing resin (B) that matrix polymer obtained with various performance classifications.The results are shown in the table 1.

Particle size distribution as the water-absorbing resin (B) that matrix polymer obtained is shown in Table 2.

Embodiment 5

Surface-treated water-absorbing resin (5) obtains by the step of following among the embodiment 1, but uses 10g water-absorbing resin (B) as matrix polymer, and uses the sodium persulfate aqueous solution of 38.5% weight of 1.3g.

Comparing embodiment 2

The surface-treated water-absorbing resin (2) that is used for comparison obtains by the step of following embodiment 5, but has omitted the use radical polymerization initiator, but utilizes the deionized water of 0.8g.

Comparing embodiment 3

The water-absorbing resin (3) that is used for comparison obtains by the step of following embodiment 5, realizes applying 1 hour step of heat but adopt in being adjusted to 180 ℃ hot-air drier in advance in the position of ultraviolet radiation.

Embodiment 6

Surface-treated water-absorbing resin (6) obtains by the step of following among the embodiment 5, but changes the mixed solution that use is made up of the aluminum sulfate aqueous solution of 50% weight of the sodium persulfate aqueous solution of 38.5% weight of 1.3g and 0.2g into.

Comparing embodiment 4

The surface-treated water-absorbing resin (4) that is used for comparison obtains by the step of following embodiment 5, but changes the aluminum sulfate aqueous solution of 50% weight of using 0.2g into.

Comparing embodiment 5

The water-absorbing resin (5) that is used for comparison obtains by the step of following embodiment 6, realizes applying 1 hour step of heat but adopt in being adjusted to 180 ℃ hot-air drier in advance in the position of ultraviolet radiation.

Production example 3

Gelatinous polymer obtains by the step of following in the production example 1, but the amount that will change internal crosslinking agent is to based on 0.09% mole of monomer.The hydrogel shaped polymer that is obtained like this in being set at 175 ℃ hot-air drier in advance dry 50 minutes.With roller flour mill dry polymer is pulverized.The gained powder is carried out classification with the sieve with 600 μ m mesh sizes, have greater than the granule of 600 μ m granularities and obtain powdery water-absorbing resin (C) as matrix polymer to remove.

Will be as powdery water-absorbing resin (C) that matrix polymer obtained with various performance classifications.The results are shown in the table 1.

Particle size distribution as the powdery water-absorbing resin (C) that matrix polymer obtained is shown in Table 2.

Embodiment 7

Surface-treated water-absorbing resin obtains by the step of following among the embodiment 5, but the water-absorbing resin (C) of use 10g is as matrix polymer.Water-absorbing resin (7) is placed by the decompression in being adjusted to 60 ℃ vacuum desiccator in advance of the water-absorbing resin that will be produced and was obtained in 12 hours.It is found that the water-absorbing resin of being produced (7) has 94.0% solids content by weight (being specified by dry weight of being lost in 3 hours 180 ℃ the time).

Embodiment 8

Water-absorbing resin (8) obtains by the step of following among the embodiment 7, but changes the mixed solution that use is made up of the aluminum sulfate aqueous solution of 50% weight of the sodium persulfate aqueous solution of 38.5% weight of 1.3g and 0.2g into.It is found that the water-absorbing resin of being produced (8) has 93.3% solids content by weight (being specified by dry weight of being lost in 3 hours 180 ℃ the time).

Embodiment 9

Water-absorbing resin (9) obtains by the step of following among the embodiment 7, but changes the mixed solution that pass through with 5: 1 ratio mix the moisture sodium lactate resulting solution composition of the aluminum sulfate aqueous solution of 50% weight and 50% weight of use by the moisture sodium peroxydisulfate of 38.5% weight of 1.3g and 0.2g into.It is found that the water-absorbing resin of being produced (9) has 93.7% solids content by weight (being specified by dry weight of being lost in 3 hours 180 ℃ the time).

Embodiment 10

Surface-treated water-absorbing resin (10) obtains by the step of following among the embodiment 1, and different is the 0.25g ammonium hydrogen sulfate will be added in the ammonium persulfate aqueous solution.

Embodiment 11

Surface-treated water-absorbing resin (11) obtains by the step of following among the embodiment 1, and different is 0.25g ammonium sulfate will be added in the ammonium persulfate aqueous solution.

Embodiment 12

Surface-treated water-absorbing resin (12) obtains by the step of following among the embodiment 1, and different is 0.25g sodium chloride will be added in the ammonium persulfate aqueous solution.

Embodiment 13

Surface-treated water-absorbing resin (13) obtains by the step of following among the embodiment 1, and different is 0.165g ammonium sulfate and 0.11g sulphuric acid will be added in the ammonium persulfate aqueous solution.

Embodiment 14

Surface-treated water-absorbing resin (14) obtains by the step of following among the embodiment 2, and different is will be before ammonium persulfate aqueous solution adds adds the mixed solution of sodium lactate aqueous solution of 60% weight of aqueous solution, 0.0025g propylene glycol and 0.0167g of aluminum sulfate 14 to 18 hydrates that comprises 50% weight of 0.1g in the water-absorbing resin (A) to.

Embodiment 15

Surface-treated water-absorbing resin (15) obtains by the step of following among the embodiment 2, and different is will be with 0.05g poly glycol monomethyl ether (number-average molecular weight: about 2,000) add in the ammonium persulfate aqueous solution.

Embodiment 16

Surface-treated water-absorbing resin (16) obtains by the step of following among the embodiment 1, and different is to use 10g water-absorbing resin (C) as matrix polymer.

Embodiment 17

Surface-treated water-absorbing resin (17) obtains by the step of following among the embodiment 16, and different is will be with 0.05g poly glycol monomethyl ether (number-average molecular weight: about 2,000) add in the ammonium persulfate aqueous solution.

Production example 4

The hydrogel shaped polymer obtains by the step of following in the production example 1, but will change the neutralization ratio to 60% mole of the monomer solution of acrylates type, and the amount that will change internal crosslinking agent is to based on 0.06% mole of monomer.The hydrogel shaped polymer that is obtained like this in being redefined for 175 ℃ hot-air drier dry 50 minutes.With roller flour mill dry polymer is pulverized.The gained powder is carried out classification with the sieve with 600 μ m mesh sizes, have greater than the granule of 600 μ m granularities and obtain powdery water-absorbing resin (D) as matrix polymer to remove.

Will be as powdery water-absorbing resin (D) that matrix polymer obtained with various performance classifications.The results are shown in the table 1.

Identical as the particle size distribution of the powdery water-absorbing resin (D) that matrix polymer obtained and powdery water-absorbing resin (C).

Embodiment 18

Surface-treated water-absorbing resin (18) obtains by the step of following among the embodiment 2, and different is to use 10g water-absorbing resin (D) as matrix polymer.

Embodiment 19

Surface-treated water-absorbing resin (19) obtains by the step of following among the embodiment 18, and different is with 0.05g poly glycol monomethyl ether (number-average molecular weight: about 2,000) add in the ammonium persulfate aqueous solution.

Production example 5

In kneading and cutting machine with two δ type blades, the preparation acrylic acid aqueous solution (monomer concentration: 30% weight) and will as the methylene-bisacrylamide of internal crosslinking agent with based on the ratio solvent of 0.15% mole of monomer in it.

Then, nitrogen is blown in this aqueous solution to reduce the oxygen concentration in the aqueous solution and to exchange the atmosphere of entire reaction internal tank.Next, under the rotation of two δ type blades, with 0.016% mole (based on monomer) as 2,2 of polymerization initiator '-azo two (2-amidine propane)-dihydrochloride and the L-ascorbic acid of 0.002% mole (based on monomer) and the hydrogen peroxide of 0.04% mole (based on monomer) add in the container.When the viscosity of acrylic acid aqueous solution increases, stop the rotation of blade, in kneading and cutting machine, carry out static polyreaction.After the temperature of production gel reaches peak value, the temperature in the kneading and cutting machine chuck is set at 70 ℃, and gel was left standstill one hour.Next, the blade in the kneading and cutting machine rotates again with abrasive gel 20 minutes.Then, add the aqueous sodium carbonate (, being equivalent to 60% mole) of 20% weight, keep the blade rotation simultaneously and continue stirring 60 minutes based on monomer.Thereby the hydrogel shaped polymer that acquisition has the 2mm particle mean size.

The hydrogel shaped polymer that is obtained like this in being set at 175 ℃ hot-air drier dry 50 minutes.Then, dry polymer is pulverized in roller flour mill and carry out classification, have greater than the granule of the particle diameter of 600 μ m and obtain powdery water-absorbing resin (E) as matrix polymer to remove with sieve with 600 μ m mesh sizes.

With therefore as water-absorbing resin (E) that matrix polymer obtained with various performance classifications.The results are shown in the table 1.

Identical as the particle size distribution of the powdery water-absorbing resin (E) that matrix polymer obtained and powdery water-absorbing resin (C).

Embodiment 20

Surface-treated water-absorbing resin (20) obtains by the step of following among the embodiment 2, and different is to use 10g water-absorbing resin (E) as matrix polymer.

Embodiment 21

Surface-treated water-absorbing resin (21) obtains by the step of following among the embodiment 20, and different is with 0.05g poly glycol monomethyl ether (number-average molecular weight: about 2,000) add in the ammonium persulfate aqueous solution.

With the surface-treated water-absorbing resin produced with various performance classifications.The results are shown in table 1 in 4.

Table 1

	GV(g/g)	Extractible polymer (%)	Water content (%)
	GV(g/g)	Extractible polymer (%)	Water content (%)	Matrix polymer (A)	34.5	12.4	92.3
Matrix polymer (B)	33.4	9.2	-	Matrix polymer (A)	34.5	12.4	92.3
Matrix polymer (B)	33.4	9.2	-	Matrix polymer (C)	32.8	7.9	93.3
Matrix polymer (D)	36.7	14.7	95.4	Matrix polymer (C)	32.8	7.9	93.3
Matrix polymer (D)	36.7	14.7	95.4	Matrix polymer (E)	35.0	2.3	94.8

Table 2

Granularity	Production example 1 matrix polymer (A)	Production example 2 matrix polymers (B)	Production example 3 matrix polymers (C)
Granularity	Production example 1 matrix polymer (A)	Production example 2 matrix polymers (B)	Production example 3 matrix polymers (C)	850μm＜	0.0％	0.0％	0.0％
600 to 850 μ m	28.0％	0.0％	0.0％	850μm＜	0.0％	0.0％	0.0％
600 to 850 μ m	28.0％	0.0％	0.0％	300 to 600 μ m	54.8％	100.0％	67.3％
300 to 150 μ m	15.0％	0.0％	30.5％	300 to 600 μ m	54.8％	100.0％	67.3％
300 to 150 μ m	15.0％	0.0％	30.5％	150μm＞	2.2％	0.0％	2.2％

Table 3

		Matrix polymer	Be used for the surface-treated condition				Water absorbing properties
			Be used for the surface-treated condition				Water absorbing properties					Water-soluble radical polymerization initiator	Initiator (% weight)	Ultraviolet or heating	Other additive (% weight)	GV (g/g)	AAP (g/g)	SFC (10 ^-7·cm ³·s·g ^-1)	Residual monomer (ppm)	Solids content (%)
			Production example 1	BP ^*(A)	-	-	-	-	-	34.5	7.5	Water-soluble radical polymerization initiator	Initiator (% weight)	Ultraviolet or heating	Other additive (% weight)	GV (g/g)	AAP (g/g)	SFC (10 ^-7·cm ³·s·g ^-1)	Residual monomer (ppm)	Solids content (%)	0	271	92.3
Embodiment 1	WAR ^**(1)	(A)	Production example 1	BP ^*(A)	-	-	-	-	-	34.5	7.5	Ammonium persulfate.	2.5	Ultraviolet 10 minutes	-	25.8	18.7	28	142	86.3	0	271	92.3
Embodiment 1	WAR ^**(1)	(A)	Embodiment 2	WAR(2)	(A)	Ammonium persulfate.	5.0	Ultraviolet 10 minutes	-	24.1	19.5	Ammonium persulfate.	2.5	Ultraviolet 10 minutes	-	25.8	18.7	28	142	86.3	48	98	86.5
Embodiment 3	WAR(3)	(A)	Embodiment 2	WAR(2)	(A)	Ammonium persulfate.	5.0	Ultraviolet 10 minutes	-	24.1	19.5	Ammonium persulfate.	5.0	Ultraviolet 5 minutes	-	24.5	18.7	21	106	86.1	48	98	86.5
Embodiment 3	WAR(3)	(A)	Embodiment 4	WAR(4)	(A)	Sodium peroxydisulfate	5.0	Ultraviolet 10 minutes	-	25.1	18.8	Ammonium persulfate.	5.0	Ultraviolet 5 minutes	-	24.5	18.7	21	106	86.1	47	111	86.4
Comparing embodiment 1	The WAR (1) that is used for comparison	(A)	Embodiment 4	WAR(4)	(A)	Sodium peroxydisulfate	5.0	Ultraviolet 10 minutes	-	25.1	18.8	Ammonium persulfate.	5.0	Heating is 10 minutes in the time of 80 ℃	-	31.4	8.0	0	256	87.5	47	111	86.4
Comparing embodiment 1	The WAR (1) that is used for comparison	(A)	Production example 2	BP ^*(B)	-	-	-	-	-	33.4	7.2	Ammonium persulfate.	5.0	Heating is 10 minutes in the time of 80 ℃	-	31.4	8.0	0	256	87.5	0	-	-
Embodiment 5	WAR(5)	(B)	Production example 2	BP ^*(B)	-	-	-	-	-	33.4	7.2	Sodium peroxydisulfate	5.0	Ultraviolet 10 minutes	-	25.7	20.8	45	-	-	0	-	-
Embodiment 5	WAR(5)	(B)	Comparing embodiment 2	The WAR (2) that is used for comparison	(B)	-	-	Ultraviolet 10 minutes	-	30.9	9.4	Sodium peroxydisulfate	5.0	Ultraviolet 10 minutes	-	25.7	20.8	45	-	-	0	-	-
Comparing embodiment 3	The WAR (3) that is used for comparison	(B)	Comparing embodiment 2	The WAR (2) that is used for comparison	(B)	-	-	Ultraviolet 10 minutes	-	30.9	9.4	Sodium peroxydisulfate	5.0	Heating is 60 minutes in the time of 180 ℃	-	33.6	7.2	0	-	-	0	-	-
Comparing embodiment 3	The WAR (3) that is used for comparison	(B)	Embodiment 6	WAR(6)	(B)	Sodium peroxydisulfate	5.0	Ultraviolet 10 minutes	Al ^*)：2	23.8	19.5	Sodium peroxydisulfate	5.0	Heating is 60 minutes in the time of 180 ℃	-	33.6	7.2	0	-	-	102	-	-
Comparing embodiment 4	The WAR (4) that is used for comparison	(B)	Embodiment 6	WAR(6)	(B)	Sodium peroxydisulfate	5.0	Ultraviolet 10 minutes	Al ^*)：2	23.8	19.5	-	-	Ultraviolet 10 minutes	Al ^*)：2	33.8	7.9	0	-	-	102	-	-
Comparing embodiment 4	The WAR (4) that is used for comparison	(B)	Comparing embodiment 5	The WAR (5) that is used for comparison	(B)	Sodium peroxydisulfate	5.0	Heating is 60 minutes in the time of 180 ℃	Al ^*)：2	32.8	7.4	-	-	Ultraviolet 10 minutes	Al ^*)：2	33.8	7.9	0	-	-	0	-	-

		Matrix polymer	Be used for the surface-treated condition				Water absorbing properties
			Be used for the surface-treated condition				Water absorbing properties					Water-soluble radical polymerization initiator	Initiator (% weight)	Ultraviolet or heating	Other additive (% weight)	GV (g/g)	AAP (g/g)	SFC (10 ^-7·cm ³·s·g ^-1)	Residual monomer (ppm)	Solids content (%)
			Production example 3	BP(C)	-	-	-	-	-	32.8	7.2	Water-soluble radical polymerization initiator	Initiator (% weight)	Ultraviolet or heating	Other additive (% weight)	GV (g/g)	AAP (g/g)	SFC (10 ^-7·cm ³·s·g ^-1)	Residual monomer (ppm)	Solids content (%)	0	202	93.3
Embodiment 7	WAR(7)	(C)	Production example 3	BP(C)	-	-	-	-	-	32.8	7.2	Sodium peroxydisulfate	5.0	Ultraviolet 10 minutes	-	26.7	21.3	40	47	94.0	0	202	93.3
Embodiment 7	WAR(7)	(C)	Embodiment 8	WAR(8)	(C)	Sodium peroxydisulfate	5.0	Ultraviolet 10 minutes	Al ^*)：2	24.0	20.4	Sodium peroxydisulfate	5.0	Ultraviolet 10 minutes	-	26.7	21.3	40	47	94.0	71	-	93.3
Embodiment 9	WAR(9)	(C)	Embodiment 8	WAR(8)	(C)	Sodium peroxydisulfate	5.0	Ultraviolet 10 minutes	Al ^*)：2	24.0	20.4	Sodium peroxydisulfate	5.0	Ultraviolet 10 minutes	Al ^**)：2	25.3	22.1	73	-	93.7	71	-	93.3

^*: matrix polymer ^*: water-absorbing resin ^{* *}: heating

^*) the aqueous sulfuric acid aluminum of 50% weight,

^*) mixed solution of the aluminum sulfate of 50% weight and 50% sodium lactate=5: 1

The amount of initiator and other additive is used based on the percetage by weight of matrix polymer and is represented.

Table 4

		Matrix polymer	Be used for the surface-treated condition				Water absorbing properties
			Be used for the surface-treated condition				Water absorbing properties					Water-soluble radical polymerization initiator	Initiator (% weight)	Ultraviolet or heating	Other additive (% weight)	GV (g/g)	AAP (g/g)	SFC (10 ^-7·cm ³·s·g ^-1)	Residual monomer (ppm)	Solids content (%)
			Embodiment 10	WAR(10)	(A)	Ammonium persulfate.	2.5	Ultraviolet 10 minutes	Ammonium hydrogen sulfate: 2.5	24.4	19.2	Water-soluble radical polymerization initiator	Initiator (% weight)	Ultraviolet or heating	Other additive (% weight)	GV (g/g)	AAP (g/g)	SFC (10 ^-7·cm ³·s·g ^-1)	Residual monomer (ppm)	Solids content (%)	71	130	86.6
Embodiment 11	WAR(11)	(A)	Embodiment 10	WAR(10)	(A)	Ammonium persulfate.	2.5	Ultraviolet 10 minutes	Ammonium hydrogen sulfate: 2.5	24.4	19.2	Ammonium persulfate.	2.5	Ultraviolet 10 minutes	Ammonium sulfate: 2.5	24.1	18.1	59	161	86.9	71	130	86.6
Embodiment 11	WAR(11)	(A)	Embodiment 12	WAR(12)	(A)	Ammonium persulfate.	2.5	Ultraviolet 10 minutes	Sodium chloride: 2.5	24.9	19.9	Ammonium persulfate.	2.5	Ultraviolet 10 minutes	Ammonium sulfate: 2.5	24.1	18.1	59	161	86.9	73	148	85.6
Embodiment 13	WAR(13)	(A)	Embodiment 12	WAR(12)	(A)	Ammonium persulfate.	2.5	Ultraviolet 10 minutes	Sodium chloride: 2.5	24.9	19.9	Ammonium persulfate.	2.5	Ultraviolet 10 minutes	Ammonium sulfate: 1.65	24.3	19.2	66	151	86.2	73	148	85.6
			Sulphuric acid: 1.1												Ammonium sulfate: 1.65
			Sulphuric acid: 1.1	Embodiment 14	WAR(14)	(A)	Ammonium persulfate.	5.0	Ultraviolet 10 minutes	Al ^***)：1.192	24.0				18.3						66	-	-
Embodiment 15	WAR(15)	(A)	Ammonium persulfate.	Embodiment 14	WAR(14)	(A)	Ammonium persulfate.	5.0	Ultraviolet 10 minutes	Al ^***)：1.192	24.0	5.0	Ultraviolet 10 minutes	Poly glycol monomethyl ether: 0.5	18.3	23.8	20.3	85	92	86.4	66	-	-
Embodiment 15	WAR(15)	(A)	Ammonium persulfate.	Embodiment 16	WAR(16)	(C)	Ammonium persulfate.	2.5	Ultraviolet 10 minutes	-	26.8	5.0	Ultraviolet 10 minutes	Poly glycol monomethyl ether: 0.5	19.8	23.8	20.3	85	92	86.4	26	31	86.2
Embodiment 17	WAR(17)	(C)	Ammonium persulfate.	Embodiment 16	WAR(16)	(C)	Ammonium persulfate.	2.5	Ultraviolet 10 minutes	-	26.8	2.5	Ultraviolet 10 minutes	Poly glycol monomethyl ether: 0.5	19.8	25.5	22.1	51	43	86.6	26	31	86.2
Embodiment 17	WAR(17)	(C)	Ammonium persulfate.	Production example 4	BP(D)	-	-	-	-	-	36.7	2.5	Ultraviolet 10 minutes	Poly glycol monomethyl ether: 0.5	6.6	25.5	22.1	51	43	86.6	0	105	95.4
Embodiment 18	WAR(18)	(D)	Ammonium persulfate.	Production example 4	BP(D)	-	-	-	-	-	36.7	5.0	Ultraviolet 10min	-	6.6	24.0	21.2	64	28	90.8	0	105	95.4
Embodiment 18	WAR(18)	(D)	Ammonium persulfate.	Embodiment 19	WAR(19)	(D)	Ammonium persulfate.	5.0	Ultraviolet 10 minutes	Poly glycol monomethyl ether: 0.5	24.6	5.0	Ultraviolet 10min	-	21.5	24.0	21.2	64	28	90.8	74	29	89.4
Production example 5	BP(E)	-	-	Embodiment 19	WAR(19)	(D)	Ammonium persulfate.	5.0	Ultraviolet 10 minutes	Poly glycol monomethyl ether: 0.5	24.6	-	-	-	21.5	35.0	7.9	0	1321	94.8	74	29	89.4
Production example 5	BP(E)	-	-	Embodiment 20	WAR(20)	(E)	Ammonium persulfate.	5.0	Ultraviolet 10 minutes	-	25.3	-	-	-	20.8	35.0	7.9	0	1321	94.8	30	738	90.1
Embodiment 21	WAR(21)	(E)	Ammonium persulfate.	Embodiment 20	WAR(20)	(E)	Ammonium persulfate.	5.0	Ultraviolet 10 minutes	-	25.3	5.0	Ultraviolet 10 minutes	Poly glycol monomethyl ether: 0.5	20.8	25.0	22.2	41	710	90.7	30	738	90.1

^{* *}) sodium lactate aqueous solution=1.0/0.025/0.167% weight (based on matrix polymer) of aqueous sulfuric acid aluminum 14～18 hydrate solns/propylene glycol/60% weight of 50% weight

For the surface treatment that resin modified given water-absorbing resin can very realize under the reaction temperature of room temperature that is near the mark satisfactorily, and the water-absorbing resin of the modification that obtains subsequently show goodly aspect water absorbing properties, so is used for disposable diaper.

The relevant part of all references is incorporated herein by reference in detailed Description Of The Invention.Quoting of any document may not be interpreted as its approval as prior art of the present invention.

Although illustrated and described the present invention with specific embodiments, it will be apparent to those skilled in the art that many other variations and modifications may be made in the case of without departing from the spirit and scope of protection of the present invention.Therefore, in additional claims, comprise all such changes and modifications that belong in the scope of the invention consciously.

Be of a size of technical size for each of value that this paper limited, it in the context of the present invention and be not understood to literal implication.Therefore, all embodiments with the size that is equivalent to the size that this paper states on the function are intended to belong to scope of the present invention, and for example, the size of " 40mm " it must be understood that to being meant " about 40mm ".

Claims

1. one kind is used for the absorption component that uses at disposable diaper, and wherein said absorption component comprises the water-absorbing resin of the modification of producing according to described method, and described method comprises:

B) with active energy roentgenization gained mixture.

2. absorption component as claimed in claim 1, wherein said water-soluble radical polymerization initiator are at least a composition that is selected from the group of being made up of following material: persulfate, hydrogen peroxide and water-soluble azo compounds.

3. one kind is used for the absorption component that uses at disposable diaper, and wherein said absorption component comprises the water-absorbing resin of the modification of producing according to described method, and described method comprises:

But a) radical polymerization initiator of mixed water-absorbent resin and thermal degradation and do not add ethylenically unsaturated monomers and

B) with active energy roentgenization gained mixture.

4. absorption component as claimed in claim 3, but the radical polymerization initiator of wherein said thermal degradation is at least a composition that is selected from the group of being made up of following material: persulfate, hydrogen peroxide and azo-compound.

5. as each described absorption component in the claim 1 to 4, the amount of wherein adding by weight the described radical polymerization initiator in 100 parts of described water-absorbing resins to is in 0.01 to 20 part scope by weight.

6. as each described absorption component in the claim 1 to 5, wherein said radical polymerization initiator mixes with the form of aqueous solution.

7. as each described absorption component in the claim 1 to 6, the mixture of wherein said water-absorbing resin and described radical polymerization initiator is with the another kind of mixture of water, described another kind of mixture-base in 100 parts of water-absorbing resins by weight in 1 to 20 part scope by weight.

8. as each described absorption component in the claim 1 to 7, the mixed aid and the step a) that wherein are different from water are added simultaneously or were added before step a).

9. absorption component as claimed in claim 8, wherein said mixed aid are that at least a water solublity that is selected from the group of being made up of following material or water can decentralized compounds: surfactant, water-soluble polymer, hydrophilic organic solvent, water-soluble inorganic compound, mineral acid, inorganic acid salt, organic acid and acylate.

10. as claim 8 or the described absorption component of claim 9, wherein said mixed aid is that at least a water solublity that is selected from the group of being made up of following material or water can decentralized compounds: polyoxyethylene alkyl ether, Polyethylene Glycol, water solublity polyvalent metal, sodium chloride, ammonium hydrogen sulfate, ammonium sulfate, sulphuric acid and hydrochloric acid.

11. as each described absorption component in the claim 8 to 10, the addition of wherein said mixed aid based on 100 parts of water-absorbing resins by weight in 0.01 to 40 part scope by weight.

12. as each described absorption component in the claim 1 to 11, wherein said water-absorbing resin has acidic-group and the neutralization ratio in 50% to 75% molar range (mole percent of neutral acidic-group in whole acidic-groups).

13. as each described absorption component in the claim 1 to 12, wherein said active energy ray be a ultraviolet.

14. as each described absorption component in the claim 1 to 13, wherein said water-absorbing resin is for having the powdered resin that monomer obtained of the acrylic acid (salt) as key component by polymerization.

15. as each described absorption component in the claim 1 to 14, wherein said water-absorbing resin has the water-absorbing resin precursor of low neutralization ratio by production and described water-absorbing resin precursor is mixed with matrix and obtains.

16. as each described absorption component in the claim 1 to 15, wherein said water-absorbing resin comprises granule, described granule has the diameter in 150 to 850 mu m ranges, and its ratio is in 90% to 100% weight range.

17. as each described absorption component in the claim 1 to 16, wherein compare with the withstand voltage absorbability of modification resin before, the withstand voltage absorbability of normal saline of the 4.83kPa of the described water-absorbing resin after the modification is enhanced and is not less than 1g/g.

18. as each described absorption component in the claim 1 to 17, wherein the withstand voltage absorbability of normal saline of the 4.83kPa of the water-absorbing resin after the modification is in 8 to 40g/g scope.

19. as each described absorption component in the claim 1 to 18, wherein the saline flow conductivity of the water-absorbing resin after the modification is not less than 10 (10-7cm3sg-1).

20. one kind is used for the absorption component that uses at disposable diaper, wherein said absorption component comprises the water-absorbing resin of powdered modification, and described water-absorbing resin comprises that by polymerization the monomer component of the acrylic acid (salt) as key component obtains, and is characterized in that having

(i) be not less than 40 (10 ^-7Cm ³Sg ^-1) the saline flow conductivity,

(ii) be no more than 95% solids content and

(iii) be no more than the residual monomer content of 150ppm.

21. one kind is used for the absorption component that uses at disposable diaper, wherein said absorption component comprises the water-absorbing resin of powdered modification as claimed in claim 20, and described water-absorbing resin has the normal saline free swell degree that is not less than 25g/g.

22. one kind is used for the absorption component that uses at disposable diaper, wherein said absorption component comprises the water-absorbing resin as claim 20 or the described powdered modification of claim 21, and described water-absorbing resin has the withstand voltage absorbability of normal saline of the 4.83kPa that is not less than 22g/g.

23. one kind is used for the absorption component that uses at disposable diaper, wherein said absorption component comprises the water-absorbing resin of the modification of producing according to described method, and described method comprises:

B) with step a) simultaneously or before step a), add the mixed aid that is different from water and

C) with active energy roentgenization gained mixture.

24. one kind is used for the absorption component that uses at disposable diaper, wherein said absorption component comprises the water-absorbing resin of the modification of producing according to described method, and described method comprises:

B) with active energy roentgenization gained mixture,

25. one kind is used for the absorption component that uses at disposable diaper, wherein said absorption component comprises the water-absorbing resin of the modification of producing according to described method, and described method comprises:

C) with active energy roentgenization gained mixture,