JP2006169284A - Absorber and blood absorbent article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a white absorber having improved absorption characteristics for a liquid containing blood and improved.
SOLUTION: A vinyl polymer (A) having a carboxyl group and an unsaturated bond and having a number average molecular weight of 500 to 50,000, (meth) acrylic acid (B), and two if necessary Absorbent resin composed of a copolymer using the above-mentioned monomer having an ethylenically unsaturated bond or a compound having two or more functional groups that react with the carboxyl group of (meth) acrylic acid (B) The present invention relates to an absorbent body comprising, and a blood absorbent article composed of the absorbent body.
[Selection figure] None

Description

  The present invention relates to an absorbent body and a blood absorbent article using a water absorbent resin having excellent performance. More specifically, the present invention relates to an absorbent body with improved absorption characteristics such as blood and body fluids, as well as gravy containing blood that oozes from food.

Traditionally, products that absorb blood or meat juice (drip) from blood-containing body fluids, blood-containing body fluids, raw meat blocks, raw fish fillets, etc., are used for sanitary napkins, drip absorbents, and even for surgery. The blood absorption sheet is used for each application.
These absorbers are required to improve absorption capacity and prevent liquid return after absorption by absorbing and holding liquid containing blood.

Examples of the water-absorbing resin used in the absorber include a hydrolyzate of starch-acrylonitrile graft copolymer, a crosslinked carboxymethyl cellulose, a crosslinked polyacrylic acid (salt), an acrylic acid (salt) -vinyl alcohol copolymer, Polyethylene oxide crosslinked products and the like are known.
However, these conventional absorbent resins are insufficient in water absorption, water retention, leakage prevention properties, etc., especially when the liquid to be absorbed is blood or the like, depending on the components contained in blood, the water absorbent resin As a result, the absorption characteristic of the absorbent material is significantly lowered, and the absorption characteristic as an absorber is low.

Therefore, for the purpose of improving the blood absorbability of the water-absorbent resin, a water-absorbent composition comprising a water-absorbent resin and an anionic surfactant and / or a nonionic surfactant of HLB7 or higher (for example, Patent Document 1). Reference), a water-absorbing material surface-treated with a polyether (see, for example, Patent Document 2), a surfactant having specific physical properties, or an absorbent composition in which the surfactant and a carboxylic acid are treated with a water-absorbing resin (For example, refer to Patent Document 3) and the like have been proposed, but the wettability to blood is slightly improved, but repeated blood absorption and dry feeling after blood absorption are insufficient.
Further, a water-absorbing material comprising a water-absorbing resin containing a polyamino acid or a salt thereof (see, for example, Patent Document 4), a sanitary napkin containing them (see, for example, Patent Document 5), a blood-absorbing sheet (see, for example, Patent Document 6), A drip absorbent (see, for example, Patent Document 7) has been proposed. However, the absorbent resin obtained by using these polyamino acids has a problem of having a brownish hue although it has excellent blood absorbability. The medical and hygiene fields, such as sanitary products and diapers where water-absorbent resins are used, are fields that are particularly required to be clean and hygienic, and the fact that the water-absorbent resin exhibits a brownish hue is clean. This is a fatal defect because it impairs the feeling and gives an unsanitary impression, and the industrial utility value of this field is extremely low.

JP 58-32641 A JP 54-70694 A JP 2002-35580 A JP 2003-245544 A Japanese Patent Laid-Open No. 2002-253611 JP 2002-263132 A JP 2002-263487 A

  Therefore, the subject of this invention is improving the absorption characteristic with respect to the liquid containing blood, and providing the white absorber improved.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors are composed of a copolymer of a vinyl polymer having a carboxyl group and an unsaturated bond and having a specific molecular weight and (meth) acrylic acid. It has been found that the use of an absorbent resin can significantly improve and improve the absorption characteristics with respect to blood-containing liquids, and the present invention has been completed.

  That is, the present invention is an absorption comprising a copolymer of a vinyl polymer (A) having a carboxyl group and an unsaturated bond and having a number average molecular weight of 500 to 50,000 and (meth) acrylic acid (B). The present invention provides an absorbent body comprising a functional resin as a constituent and a blood absorbent article comprising the absorbent body.

  Since the absorbent body of the present invention is excellent in absorption characteristics of liquid containing blood, it is useful for blood absorbent articles such as sanitary napkins, tampons, medical blood absorbent sheets, drip absorbents and the like.

The matters necessary for carrying out the present invention will be specifically described below.
The absorbent body of the present invention is an absorbent body containing a water absorbent resin at least in part.
Part or all of the absorbent resin in the present invention has a carboxyl group and an unsaturated bond, and a number average molecular weight of 500 to 50,000 vinyl polymer (A) and (meth) acrylic acid (B ) And a copolymer.
The vinyl polymer (A) has a carboxyl group from the viewpoint of blood absorption of the resulting absorbent resin. Thereby, the blood-absorbing property and blood retention stability of the obtained absorbent resin can be improved, and a decrease in blood-absorbing property when blood is repeatedly absorbed can be suppressed.
The vinyl polymer (A) has an unsaturated bond for reacting with a water-soluble ethylenically unsaturated monomer. It is preferable that 1 to 3 of such unsaturated bonds are present in one molecule of the vinyl polymer from the viewpoint of suppressing aggregation of particles made of the resulting superabsorbent resin.

The vinyl polymer (A) has a number average molecular weight of 500 to 50,000. When the number average molecular weight is less than 500 or exceeds 50,000, the blood-absorbing property of the superabsorbent resin and the blood-absorbing property when blood is repeatedly absorbed are lowered. Therefore, the number average molecular weight of the vinyl polymer is preferably in the range of 1,000 to 5,000, and more preferably in the range of 2,000 to 4,000.
The vinyl polymer (A) can be produced, for example, by mixing and stirring an aqueous solution of a vinyl polymer having a carboxyl group and a compound having an epoxy group and an unsaturated bond. In this case, it is preferable to react at 40 ° C. to 90 ° C. for 10 minutes to 1 hour.

Examples of the compound having an epoxy group and an unsaturated bond include allyl glycidyl ether and glycidyl (meth) acrylate. Among these, glycidyl methacrylate is preferable because it can suppress a side reaction when the vinyl polymer having a carboxyl group is reacted in water.
Even if the vinyl polymer having a carboxyl group is a homovinyl polymer obtained by polymerizing one kind of vinyl monomer, a block copolymer obtained by polymerizing two or more kinds of vinyl monomers or a random copolymer. A copolymer may also be used.

Examples of the vinyl monomer having a carboxyl group include (meth) acrylic acid, maleic acid, fumaric acid and the like. Examples of other vinyl monomers that can be used include amide groups or hydroxyl groups such as (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. The vinyl polymer which has can be mentioned.
The vinyl polymer having a carboxyl group is obtained by radical polymerization of the vinyl monomer having a carboxyl group and, if necessary, the other vinyl monomer in the presence of a radical polymerization initiator in an aqueous solvent. Can be manufactured.

Examples of the radical polymerization initiator include peroxides such as hydrogen peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate, and 2,2′-azobis- (2-aminodipropane) dihydrochloride, 2'-azobis- (N, N'-dimethyleneisobutylamidine) dihydrochloride, 2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propion An azo compound such as amide} can be used, and these can be used alone or in combination of two or more.
The vinyl polymer may have its carboxyl group neutralized with a basic compound. What can be used as such a basic compound is, for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, etc. Among them, it is preferable to use sodium hydroxide or potassium hydroxide.

  The (meth) acrylic acid (B) used in the present invention contains (meth) acrylic acid and / or a salt such as an alkali metal salt or ammonium salt thereof. Such (meth) acrylic acid (B) may be used alone or, if necessary, a vinyl monomer having a hydrophilic group other than (meth) acrylic acid may be used in combination. When used in combination, (meth) acrylic acid is preferably used in an amount of 50% by weight or more in producing a highly absorbent resin having excellent absorbency. Examples of the vinyl monomer having a hydrophilic group include ionic monomers and nonionic monomers. Examples of the ionic monomer include acrylamido-2-methylpropane sulfonic acid, allyl sulfonic acid, vinyl sulfonic acid, and 4-sulfobutyl methacrylate soda salt. Examples of the nonionic monomer include (meth) acrylamide, N, N-dimethylacrylamide, 2-hydroxyethyl (meth) acrylate, N-methylol (meth) acrylamide and the like.

  The (meth) acrylic acid (B) is preferably obtained by neutralizing a carboxyl group thereof with a basic compound. At this time, it is preferable to neutralize 20-100 mol% of the said carboxyl group, and it is more preferable to neutralize 30-60 mol%. Thereby, the absorptivity of the obtained highly water-absorbent resin can be further improved. Examples of the basic compound include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide and the like. Among these, sodium hydroxide and potassium hydroxide are preferably used.

  The (meth) acrylic acid (B) used in the present invention has 2 functional groups that react with the monomer having two or more ethylenically unsaturated bonds or the carboxyl group of the (meth) acrylic acid (B). It is preferable to use a compound having at least one as a crosslinking agent. These crosslink the polymers obtained by polymerizing the (meth) acrylic acid (B). The polymers obtained by polymerizing the (meth) acrylic acid (B) may self-crosslink without using the cross-linking agent. However, by using the cross-linking agent, the polymer is excellent in absorbability, particularly blood absorption. A water-absorbing resin can be produced.

  Examples of the monomer having two or more ethylenically unsaturated bonds include di (meth) acrylic acid ester, tri (meth) acrylic acid ester, bisacrylamide, and polyvalent allyl compound. Examples of di (meth) acrylic acid esters include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, di (meth) acrylic acid carb Examples include mill esters. Examples of the tri (meth) acrylic acid ester include trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate. Examples of bisacrylamide include N, N′-methylenebisacrylamide and N, N′-ethylenebisacrylamide. Examples of the polyvalent allyl compound include diallyl phthalate, tetraallyloxyethane, pentaerythritol triallyl ether, trimethylolpropane triallyl ether, diethylene glycol diallyl ether, triallyl trimellitate and the like. Among the monomers having two or more ethylenically unsaturated bonds, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, N, N′-methylenebis ( It is preferred to use (meth) acrylamide.

Examples of the compound having two or more functional groups that react with the carboxyl group of the (meth) acrylic acid (B) include compounds having two or more epoxy groups, compounds having two or more isocyanate groups, and the like. Among these, it is preferable to use a diglycidyl ether compound.
Examples of the compound having two or more epoxy groups include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, and polyglycerin diglycidyl ether. Of these, ethylene glycol diglycidyl ether is preferably used.
Examples of the compound having two or more isocyanate groups include 2,4-tolylene diisocyanate and hexamethylene diisocyanate.

  The monomer having two or more ethylenically unsaturated bonds and the compound having two or more functional groups that react with the carboxyl group of the (meth) acrylic acid (B) are the above (meth) acrylic acid (B ) It must be used within the range of 0.01 to 1 part by weight per 100 parts by weight. Among these, it is preferable that it exists in the range of 0.01-0.5 weight part. When the amount is less than 0.01 part by weight, a sufficient crosslinked structure cannot be obtained, and when the amount is more than 0.5 part by weight, the absorption performance is lowered.

  An absorbent resin made of a copolymer of a vinyl polymer (A) and (meth) acrylic acid (B) is prepared by mixing, for example, an anionic surfactant and a radical in a hydrophobic organic solvent containing a nonionic surfactant. An aqueous solution containing a polymerization initiator is sequentially supplied to perform water-in-oil type reverse phase suspension polymerization, and then an aqueous solution containing the vinyl polymer is supplied to perform water-in-oil type reverse phase suspension polymerization. And can be produced by drying the resulting polymer slurry. This method is preferable in that surface porous particles in which a large number of fine particles are bound to each other are formed by a synergistic effect of an anionic surfactant and a nonionic surfactant.

  Examples of the hydrophobic organic solvent used in the present invention include aliphatic hydrocarbon solvents such as n-pentane, n-hexane, n-heptane and n-octane, alicyclic hydrocarbon solvents such as cyclohexane and methylcyclohexane, and benzene. And aromatic hydrocarbon solvents such as toluene and xylene. Among these, it is preferable to use n-hexane, n-heptane or cyclohexane which has a lower boiling point than water and can form an azeotrope with water. The hydrophobic organic solvent is preferably used 0.5 to 10 times, more preferably 0.8 to 3 times, with respect to the (meth) acrylic acid (B). Thereby, it can suppress that the particle | grains of the water absorbent resin obtained aggregate.

  As the surfactant in the hydrophobic organic solvent, any known nonionic surfactant or anionic surfactant in the method for producing a water-absorbing resin by the reverse phase suspension polymerization method, nonionic surfactant, nonionic surfactant Copolymer, such as an ionic copolymer, an anionic copolymer, and a cationic copolymer, and other inorganic salts. Among these, since it is excellent in solubility and dispersibility in a hydrophobic organic solvent, the (meth) acrylic acid (B) in a hydrophobic organic solvent, a compound having two or more ethylenically unsaturated bonds, or ( A nonionic surfactant is preferred in that it is excellent in dispersibility of an aqueous solution containing a compound having two or more functional groups that react with the functional group of the (meth) acrylic acid (B) and a radical polymerization initiator.

  Nonionic surfactants include, for example, polyoxyalkylene sorbitan fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyoxyalkylene sorbitol fatty acid esters, polyoxyalkylene glycerin fatty acid esters, liglycerin fatty acid esters, polyoxyalkylene fatty acid esters. , Polyoxyalkylene alkyl ether, polyoxyethylene polyoxypropylene block copolymer, phosphoric acid triester and the like. The polyoxyalkylene sorbitan fatty acid ester is preferably a polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene having an HLB of 9 to 11 determined by the following definition formula Examples include sorbitan trioleate, and these may be used alone or in combination of two or more.

Examples of the sorbitan fatty acid ester include sorbitan monolaurate having 4 to 9 HLB, sorbitan monostearate, sorbitan monooleate and the like. Examples of the sucrose fatty acid ester include sucrose stearate having 4 to 13 HLB, sucrose palmitate, sucrose oleate, sucrose laurate, and the like. Examples of the polyoxyalkylene sorbitol fatty acid ester include polyoxyethylene sorbitol tetraoleate having an HLB of 10.5. Examples of the polyoxyalkylene glycerol fatty acid ester include polyoxyethylene glycerol monostearate having 9 to 10 HLB, polyoxyethylene glycerol monooleate, and the like. Examples of the polyoxyalkylene fatty acid ester include polyoxyethylene oleic acid ester having 7 to 13 HLB, polyoxyethylene lauric acid ester, and the like. Examples of the polyoxyalkylene alkyl ether include polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyalkylene lauryl ether, polyoxyethylene alkyl ether, and the like having 5 to 13 HLB. Examples of the phosphoric acid triester, for example, an HLB of different polyoxyethylene chain length of 7-14, tri dioxyethylene (C ₁₂ -C ₁₅₎ alkyl ether phosphates, tri hexaoxyethylene (C ₁₂ -C ₁₅₎ alkyl ether Examples thereof include phosphoric acid, trioctaoxyethylene (C ₁₂ -C ₁₅ ) alkyl ether phosphoric acid, and tridecaoxyethylene (C ₁₂ -C ₁₅ ) alkyl ether phosphoric acid.

  Examples of the radical polymerization initiator used in the present invention include peroxides such as hydrogen peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate, and 2,2′-azobis- (2-aminodipropane) 2 hydrochloric acid. Salt, 2,2'-azobis- (N, N'-dimethyleneisobutylamidine) dihydrochloride, 2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2- Azo compounds such as hydroxyethyl] propionamide}, and these may be used alone or in combination of two or more. At this time, a reducing substance such as sulfite and L-ascorbic acid, an amine salt, or the like can be used in combination with the peroxide as a redox initiator. It is necessary to use 0.1 to 1 part by weight of the radical polymerization initiator with respect to 100 parts by weight of the (meth) acrylic acid (B).

Examples of the anionic surfactant include N-acyl amino acid salts, polyoxyethylene alkyl ether carboxylates, acylated peptides, alkyl sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, and naphthalene sulfonates. Formalin polycondensate, sulfosuccinate, α-olefin sulfonate, N-acyl sulfonate, polyoxyethylene alkyl ether sulfonate, alkyl amide sulfate, alkyl phosphate, polyoxyethylene alkyl ether phosphate Salt, polyoxyethylene alkyl allyl ether phosphate ester salt, sulfated oil and the like.
Among these, it is preferable to use the α-olefin sulfonate represented by the general formula (I) in order to reduce the adhesion of the polymer to the pot wall and the stirring blade.

一般式（Ｉ）中のＲ’は、炭素原子数８〜３０のアルケニル基又は炭素原子数８〜２４のヒドロキシアルキル基を示す。Ｍは、アルカリ金属、第４級アンモニウム又は第４級アミンを示すものである。
炭素原子数８〜３０のアルケニル基としては、例えばヘキサデセニル基、テトラデセニル基、ドデセニル基、オクタデセニル基、デセニル基、オクテニル基等が挙げられる。また、炭素原子数８〜２４のヒドロキシアルキル基としては、例えばヒドロキシラウリル基、ヒドロキシオクチル基、ヒドロキシヘキサデシル基、ヒドロキシテトラデシル基、ヒドロキシオクタデシル基、ヒドロキシデシル基等が挙げられる。
一般式（Ｉ）中におけるＭは、入手のし易さの観点から、アルカリ金属であるものが好ましい。

R ′ in the general formula (I) represents an alkenyl group having 8 to 30 carbon atoms or a hydroxyalkyl group having 8 to 24 carbon atoms. M represents an alkali metal, quaternary ammonium or quaternary amine.
Examples of the alkenyl group having 8 to 30 carbon atoms include a hexadecenyl group, a tetradecenyl group, a dodecenyl group, an octadecenyl group, a decenyl group, and an octenyl group. Examples of the hydroxyalkyl group having 8 to 24 carbon atoms include a hydroxylauryl group, a hydroxyoctyl group, a hydroxyhexadecyl group, a hydroxytetradecyl group, a hydroxyoctadecyl group, and a hydroxydecyl group.
M in the general formula (I) is preferably an alkali metal from the viewpoint of easy availability.

The α-olefin sulfonate having an alkenyl group having 8 to 30 carbon atoms is preferably an alkene (C _{8 to} C ₃₀ ) monosulfonate, such as sodium octadecene sulfonate, sodium hexadecene sulfonate, tetradecene sulfone. Examples include sodium acid, sodium dodecene sulfonate, sodium decene sulfonate, and sodium octene sulfonate.
The α-olefin sulfonate having a hydroxyalkyl group having 8 to 24 carbon atoms is preferably a hydroxyalkane (C _{8 to} C ₂₄ ) sulfonate, such as sodium hydroxylauryl sulfonate, sodium hydroxyoctyl sulfonate, hydroxy Examples include sodium hexadecyl sulfonate, sodium hydroxytetradecyl sulfonate, sodium hydroxyoctadecyl sulfonate, sodium hydroxydecyl sulfonate, and the like.
Since these α-olefin sulfonates are industrially obtained by sulfonation of α-olefins, the alkene (C ₈ -C ₃₀ ) monosulfonate and hydroxyalkane (C ₈ -C) are usually available. ₂₄ ) Mixtures of sulfonates, and these normally available mixtures can also be suitably used in the present invention.

Next, a more specific embodiment of the method for producing a water absorbent resin of the present invention will be described.
First, a hydrophobic organic solvent containing a surfactant, preferably a nonionic surfactant, is adjusted to an appropriate polymerization reaction temperature in the range of 40 to 150 ° C., preferably in the range of 60 to 90 ° C. Then, in this hydrophobic organic solvent, (meth) acrylic acid and, if necessary, vinyl monomers having other hydrophilic groups are combined, and two or more ethylenically unsaturated bonds are added per 100 parts by weight. Or a compound having two or more functional groups that react with the carboxyl group of (meth) acrylic acid, a radical polymerization initiator, and an aqueous solution containing an anionic surfactant as necessary (hereinafter referred to as “single”). Abbreviated as “mermer aqueous solution”). As a result, the monomer can be finely dispersed in a hydrophobic organic solvent, and water-in-oil type reverse phase suspension polymerization is performed.
After the monomer aqueous solution is sequentially supplied into the hydrophobic organic solvent, the polymer has a carboxyl group and an unsaturated bond, and has a weight average molecular weight of 500 to 10,000 (hereinafter abbreviated as “vinyl polymer”). (A) is supplied into the hydrophobic organic solvent, and the supply method at this time may be batch addition or sequential supply.

The aqueous solution of the vinyl polymer (A) is preferably supplied within 2 hours immediately after the monomer aqueous solution is sequentially supplied. Thereby, the particle | grain surface of the polymer obtained by polymerizing a monomer is stabilized and it can prevent that particle | grains fuse | melt.
After supplying the aqueous solution of the vinyl polymer (A), it is stirred for 10 minutes to 3 hours at 60 ° C. to 80 ° C. to contain swollen beaded water-absorbent resin, hydrophobic organic solvent and surfactant. A slurry-like mixture can be obtained. The water-absorbent resin can be separated from the slurry mixture by, for example, azeotropic dehydration or heat drying.

As the azeotropic dehydration method, for example, the slurry mixture and an organic solvent such as cyclohexane are mixed and dehydrated until the water content in the resin solid content becomes 25 to 5% by weight while maintaining the azeotropic temperature of water and the organic solvent. The method of doing is mentioned. After the azeotropic dehydration, the water-absorbent resin and cyclohexane are separated by, for example, a decantation method or a filtration method, and then dried to produce a powdery superabsorbent resin.
Examples of the heat drying method include a method using a vacuum dryer, a hot air dryer, an air flow dryer, a fluidized bed dryer, a drum dryer and the like. The drying temperature is preferably 50 ° C. or higher, more preferably in the range of 60 to 200 ° C., and still more preferably in the range of 70 to 180 ° C. By drying within such a temperature range, decomposition of the superabsorbent resin due to heat can be prevented, and as a result, a decrease in absorbability can be prevented.

The absorbent body in the present invention contains the water-absorbent resin as a constituent component.
Examples of the structure of the absorber include a sheet structure in which the water-absorbent resin is sandwiched between highly diffusive and highly permeable sheets. Here, as the highly diffusive and highly permeable sheet, perforated or non-porous paper or nonwoven fabric is preferably used. When paper is used as a sheet, it may be a paper made of softwood pulp, hardwood pulp, mulberry, Mitsumata, and a mixture of these with rayon, polyethylene, and cotton fibers. Examples of the raw material for the nonwoven fabric include natural fibers such as cotton, pulp, and wool, regenerated fibers such as rayon, and synthetic fibers manufactured from synthetic polymers such as vinylon, nylon, polyester, polyethylene, polypropylene, and acrylic. . These fibers may be used alone or may be mixed and composited. When synthetic fibers are used as the raw material for the nonwoven fabric, the fibers used may be fibers blended with different polymers, fibers having a core-sheath structure, or fibers having a bimetal structure. Moreover, the cross section of the fiber may also have an atypical cross section structure other than the normal circular fiber. The manufacturing method of a nonwoven fabric is not specifically limited, You may manufacture by the conventionally well-known method. Depending on the fiber used, all known technologies such as chemical bond method, fiber lock method, air lay method, stitch bond method, spun bond method, melt blow method, spun lace method, thermal bond method, needle punch method, wet method, etc. Can be adopted.

As a method of processing an integral absorbent body from a highly diffusive and highly permeable sheet and a water absorbent resin, the water absorbent resin is evenly spread on a sheet that has been previously wetted with water, or on the sheet. After the water-absorbing resin is uniformly sprayed, it can be integrated by spraying steam or mist of water to make the water-absorbing resin into a paste, and then crimping with a highly diffusive and highly permeable sheet. At this time, the water-absorbing resin may be spread on one half of the highly diffusive and highly permeable sheet, and the absorbent resin may be wrapped and integrated with only one sheet, or the absorbent resin may be highly diffused and permeable. It is also possible to integrate them by spreading them on one highly reliable sheet and sandwiching them with another sheet. Moreover, when the adhesiveness of the water absorbent resin is weak and the strength cannot be maintained, a binder can be used in combination. The mixing ratio of the water absorbent resin to the highly diffusive and highly permeable sheet is preferably 10 to 500 g / m ² of the water absorbent resin.

  Further, the structure of the absorbent body may be a structure in which a water-absorbent resin is dispersed and mixed in a water-absorbent fiber. Examples of water-absorbing fibers include fluff pulp, that is, cellulose fibers, and artificial cellulose fibers such as rayon and acetate. Furthermore, hydrophobic synthetic fibers such as olefins such as polyethylene and polypropylene, polyesters, and polyamides may be used in combination. Pulp is a chemical pulp, mechanical pulp, or a sheet of chemical mechanical pulp made into cotton by a pulverizer. The raw material for pulp is not limited to coniferous trees, but hardwoods can also be used. In addition, waste paper pulp, straw, bamboo, kenaf and the like can also be used.

  The absorbent body may have a single-layer structure formed by mixing the above-described water-absorbent fibers and an absorbent resin, or may have a structure in which a water-absorbent fiber layer is laminated on the absorbent resin layer, or A structure in which a layer formed by mixing a superabsorbent polymer and a superabsorbent fiber on the superabsorbent fiber layer may be laminated, and the superabsorbent polymer and the superabsorbent fiber are interposed between the two superabsorbent fiber layers. A structure in which mixed layers are stacked may be used. The mixing ratio of the water absorbent fiber and the superabsorbent polymer is preferably 10 to 1000 parts by weight of the water absorbent resin with respect to 100 parts by weight of the water absorbent fiber, and further 10 to 500 parts by weight of the water absorbent resin with respect to 100 parts by weight of the water absorbent fiber. preferable. As a method for forming the water-absorbing fiber into a sheet, it is desirable to adopt a known dry pulp air raid system. By adopting this method, the water absorbent resin can be uniformly dispersed in the water absorbent fibers. The dry pulp air raid method is a method in which a water-absorbing fiber and an absorbent resin are carried in an air flow to form a web. When compression-molding a liquid-absorbing sheet composed of the materials as described above, the surface has a smooth shape so that the density is uniform, or embossing is performed to guide the liquid in the longitudinal and diagonal directions. It may be partially different.

  Since the absorbent body in the present invention is excellent in blood absorbability, it can be used as a blood-absorbent article in a bag having a liquid-permeable sheet. Examples of the bag having a liquid permeable sheet include a liquid permeable sheet and a non-liquid permeable sheet that does not permeate liquid or is difficult to permeate. In this case, according to the liquid permeable sheet, The configured part becomes a part that can transmit liquid. A liquid-permeable sheet and a non-liquid-permeable sheet are stacked on top and bottom, and the periphery of these liquid-permeable sheet and non-liquid-permeable sheet is sealed to form a bag. The other surface is a surface that does not or does not easily transmit liquid.

  As other bag embodiments, for example, two liquid permeable sheets are stacked up and down to seal the periphery, and two non-liquid permeable sheets are stacked up and down to surround the periphery. Examples thereof include a bag-like shape formed by sealing, which is made liquid-permeable by forming a large number of slits or pores in one non-liquid-permeable sheet. The liquid-permeable sheet is made of a material that has a permeability that allows liquid to permeate, water resistance, and a density (pore diameter) that does not allow the absorbent of the present invention to exude, and that does not adversely affect the human body. More preferred are non-woven fabrics such as wet nonwoven fabrics, spun pond nonwoven fabrics, hydroentangled nonwoven fabrics, and paper. Further, the non-liquid permeable sheet is preferably composed of a material that has non-permeability and water resistance that does not permeate liquid or is difficult to permeate, and does not adversely affect the human body. For example, a non-liquid-permeable sheet is preferably a synthetic resin film such as a polypropylene film, a polyethylene film or a polyamide film having a thickness in the range of 10 to 50 microns, more preferably 20 to 30 microns, or a polypropylene film and a polyethylene film. A two-layer film having a thickness of 20 to 100 microns, more preferably 25 to 40 microns can be suitably used. In this case, a small hole or a slit may be formed in the non-liquid permeable sheet in a range where the liquid permeability is lower than that of the liquid permeable sheet.

Further, the blood-absorbing article has an absorber disposed between a liquid-permeable sheet made of a nonwoven fabric, a porous plastic sheet, etc., and a non-liquid-permeable leak-proof material made of a polyethylene sheet or a polyethylene sheet laminated nonwoven fabric. However, a structure in which the outer edge portion is joined by an adhesive such as hot melt or an adhesive means such as heat sealing may be used. Further, if necessary, a part for preventing side leakage, for example, a part called gather in the case of a sanitary napkin, may be attached to both sides.
The blood-absorbing article of the present invention includes sanitary napkins, tampons, surgical blood-absorbing sheets, drip-absorbing sheets from seafood and meat, pads for protecting wound sites, wound dressings, highly functional gauze, hemostatic agents It can be used as a dental apron, a pet sheet, a blood / waste liquid absorbing sheet for animal experiments / anatomy, and the like.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the following, all percentages are based on weight unless otherwise specified. Various properties of the resin were measured by the following methods.

[Measurement method of resin blood absorption]
In a petri dish having an inner diameter of 95 mm, about 1.0 g of polymer particles obtained in Examples described later were weighed, and 20 g of equine defibrinated blood was added to absorb the blood for 1 minute. After 1 minute, the contents of the petri dish were taken out on a 20 cm-diameter filter paper layered five times, and excess blood was absorbed by the filter paper by sandwiching with the 20 cm-diameter filter paper layered from the top. The weight of the remaining gel material was weighed, and the amount of blood absorbed by 1 g of the polymer particles was measured by subtracting 1.0 g of the weight of the first polymer particles from the weight of the gel material.

[Measurement method of blood absorption of absorber]
In the flask, 50 g of equine defibrinated blood was weighed, and the absorbent body cut into 4 × 4 cm was immersed in the flask for 5 minutes to absorb blood. After absorbing the blood, the absorber was picked up with tweezers and held in the air until the blood stopped dripping. The weight of the absorbent was measured, and the blood suction amount (g) was calculated by subtracting the weight of the sheet before blood absorption.

(Reference Example 1) (Preparation example of vinyl polymer (a) having carboxyl group and unsaturated bond)
A reaction vessel equipped with a stirrer, a dropping device, a reflux device, and a nitrogen gas introduction tube was charged with 187.7 parts of ion-exchanged water and heated to 93 ° C. in a nitrogen atmosphere.
Next, at the same temperature, a solution consisting of 124.3 parts of acrylic acid, 9.8 parts of sodium persulfate and 61.29 parts of ion-exchanged water was added dropwise over 2 hours each. After completion of dropping, the temperature was kept at the same temperature for 6 hours, and then the temperature was lowered to 25 ° C. A 30% aqueous solution of sodium hydroxide was added thereto, the resin solid content (hereinafter abbreviated as NV) was 35%, and the Gardner viscosity (hereinafter abbreviated as VIS.) Was CD. Thus, a polyacrylic acid resin having a pH of 2.61 was obtained. Next, 100 parts of the obtained polyacrylic acid resin was charged into another reaction vessel equipped with a stirrer, a dropping device, a reflux device, and an air introduction tube, and the temperature was raised to 70 ° C. in an air atmosphere. At the same temperature, 2.4 parts of glycidyl methacrylate (hereinafter abbreviated as GMA) was added and held at that temperature for 1 hour. After the reaction, 24.4 parts of a 30% aqueous solution of sodium hydroxide was added to obtain a solution of a vinyl polymer (a) having a carboxyl group and an unsaturated bond having a pH of 5.07. When the molecular weight was measured using a liquid chromatograph CCPM manufactured by Tosoh Corporation with two connected columns of TSKGEL columns G5000PSX and G3000PSX and using phosphate buffer (pH = 7.0) as a medium, the number average molecular weight was 3, 000.

(Reference Example 2) (Preparation example of vinyl polymer (b) having carboxyl group and unsaturated bond)
A reaction vessel equipped with a stirrer, a dropping device, a reflux device, and a nitrogen gas introduction tube was charged with 187.7 parts of ion-exchanged water and heated to 93 ° C. in a nitrogen atmosphere.
Next, at the same temperature, a solution consisting of 124.3 parts of acrylic acid, 3.7 parts of sodium persulfate and 61.29 parts of ion-exchanged water was added dropwise over 2 hours each. After completion of dropping, the temperature was kept at the same temperature for 6 hours, and then the temperature was lowered to 25 ° C. To this was added a 30% aqueous solution of sodium hydroxide, and N.I. V. Is 35% and VIS. Obtained a polyacrylic acid resin having a pH of 2.57. Subsequently, 100 parts of the polyacrylic acid resin obtained above was charged in another reaction vessel equipped with a stirrer, a dropping device, a reflux device, and an air introduction tube, and the temperature was raised to 70 ° C. in an air atmosphere. At the same temperature, 0.9 part of GMA was added and held at that temperature for 1 hour. After the reaction, 24.4 parts of a 30% aqueous solution of sodium hydroxide was added to obtain a solution of a vinyl polymer (b) having a pH of 5.02 and having a carboxyl group and an unsaturated bond. When the molecular weight was measured, the number average molecular weight was 8,000.

(Reference Example 3) (Preparation example of vinyl polymer (c) having carboxyl group and unsaturated bond)
In a reaction vessel equipped with a stirrer, a dropping device, a reflux device, and a nitrogen gas introduction tube, 319.9 parts of ion-exchanged water was charged and heated to 93 ° C. in a nitrogen atmosphere.
Next, at the same temperature, a solution consisting of 65.1 parts of acrylic acid, 195.2 parts of hydroxyethyl acrylate, 20.2 parts of sodium persulfate and 105 parts of ion-exchanged water was added over 2 hours. And dripped. After completion of dropping, the temperature was kept at the same temperature for 6 hours, and then the temperature was lowered to 25 ° C. To this was added a 30% aqueous solution of sodium hydroxide, and N.I. V. Is 35% and VIS. Was obtained, and a resin solution having a pH of 2.61 was obtained. Subsequently, 80 parts of the polyacrylic acid resin obtained above was charged in another reaction vessel equipped with a stirrer, a dropping device, a reflux device, and an air introduction tube, and the temperature was raised to 70 ° C. in an air atmosphere. At the same temperature, 2.0 parts of GMA was added and kept at the same temperature for 1 hour. After the reaction, 5.2 parts of a 30% aqueous solution of sodium hydroxide was added to obtain a vinyl polymer (c) solution having a carboxyl group and an unsaturated bond having a pH of 5.22. When the molecular weight was measured, the number average molecular weight was 4,000.

Reference Example 4 (Preparation example of polyaspartic acid having an ethylenically unsaturated group)
96 g of maleic anhydride and 50 g of ion-exchanged water were added to a 1 L four-necked flask equipped with a stirrer, a thermometer, a reflux device, and a nitrogen gas blowing device. Next, the mixture was heated to 55 ° C. to dissolve maleic anhydride, and then cooled once to obtain a maleic anhydride slurry. The system was heated again and when the temperature reached 55 ° C., 60.8 g of 28% aqueous ammonia was added. Thereafter, the temperature in the system was raised to 80 ° C. After reacting for 3 hours, the obtained aqueous solution was dried to obtain a reaction intermediate. A 2 L eggplant flask was charged with 100 g of the reaction intermediate and 10 g of 85% phosphoric acid, and reacted for 4 hours at 200 ° C. under reduced pressure in an oil bath temperature using an evaporator. The obtained product was washed several times with water and methanol to obtain a polysuccinimide powder. As a result of measuring the obtained polysuccinimide by GPC, the weight average molecular weight was 3000.
Next, 75 g of an aqueous solution in which 20.6 g of sodium hydroxide was dissolved was added to another reactor equipped with a stirrer, a thermometer, a reflux device, and a nitrogen gas blowing device, and then the poly-aluminum obtained in Reference Example 1 was added. An aqueous solution of polysuccinimide was obtained by adding 50 g of acid imide powder. Next, after raising the temperature to 90 ° C., 5.0 g of glycidyl methacrylate was added, and the reaction was performed for 1 hour to obtain an aqueous solution containing a hydrolyzate of polyaspartic acid having a methacryloyl group introduced.

<< Reference Example 5 >> Method for Producing Water Absorbent Resin 1 To a 500 ml Erlenmeyer flask was added 30 g of acrylic acid, and 81.5 g of an aqueous lithium hydroxide solution containing 8.74 g of lithium hydroxide monohydrate dissolved while cooling from the outside. The solution was added dropwise to neutralize 50 mol% of acrylic acid. To this solution, 1.89 g of Latemuru PS (sodium alkanesulfonate Kao Corporation) was added and dissolved. Further, 23.4 mg of N, N′-methylenebisacrylamide and 0.05 g of ammonium persulfate were added to this solution and dissolved.
Separately from this, 164 g of cyclohexane was added to a 500 ml four-necked flask equipped with a stirrer, a thermometer, a reflux device, and a nitrogen gas blowing device, and this was added with Rhedol TW-O106V (polyoxyethylene sorbitol monooleate (EO; 6 mol adduct) (HLB = 10.0) manufactured by Kao Corporation) 0.41 g was added and dispersed while stirring at 500 rpm. Next, after the flask was purged with nitrogen, the temperature was raised to 75 ° C., and the acrylic acid aqueous solution prepared above was added dropwise over 60 minutes. After the dropwise addition, 8 g of the previously obtained carboxyl group-containing vinyl polymer (a) was added all at once. Subsequently, after hold | maintaining at 70-75 degreeC for 3 hours, it spin-dry | dehydrated until the water content of the resin produced | generated by the azeotrope with a cyclohexane became 10%. Stirring was performed constantly at a rotation speed of 500 rpm. After completion of the reaction, the cyclohexane phase is separated by decantation, and then the water-containing polymer particles obtained are dried under reduced pressure at 70 ° C. for 3 hours and further dried under reduced pressure at 180 ° C. for 1 hour, so that the water content becomes 5%. The water-absorbent resin 1 was obtained.

Reference Example 6 Production Method of Water Absorbent Resin 2 A water absorbent resin 2 was obtained by the same operation as in Reference Example 5 except that the carboxyl group-containing vinyl polymer (a) was changed to (b).
Reference Example 7 Production Method of Water Absorbent Resin 3 A water absorbent resin 3 was obtained in the same manner as in Reference Example 5 except that the carboxyl group-containing vinyl polymer (a) was changed to (c).
<< Reference Example 8 >> Method for Producing Water Absorbent Resin 4 A brown water absorbent resin is obtained by the same operation as in Reference Example 1 except that the carboxyl group-containing vinyl polymer (a) is changed to polyaspartic acid having an ethylenically unsaturated group. 4 was obtained.

<< Reference Example 9 >> Method for Producing Water Absorbent Resin 5 150 g of acrylic acid is added to a 500-liter descup, and 341.5 g of an aqueous solution of sodium hydroxide in which 33.3 g of sodium hydroxide is dissolved is added dropwise while cooling from outside. 50 mol% was neutralized. Subsequently, 468 mg of N, N′-methylenebisacrylamide and 620 mg of ammonium persulfate were added and dissolved. 2. 820 g of cyclohexane is added to a 2 L four-necked flask equipped with a stirrer, a thermometer, a reflux device, and a nitrogen gas blowing device, to which is added Rhedol Super SP-S10 (sorbitan monostearate, manufactured by Kao Corporation). 75 g was added and dispersed while stirring at 350 rpm. Next, after the inside of the flask was purged with nitrogen, the prepared aqueous acrylic acid solution was added and mixed. After the addition, the flask was heated by heating in a water bath at 80 ° C., and heat was generated when the temperature exceeded 70 ° C. After holding at 65 to 75 ° C. for 3 hours, dehydration was performed until the water content of the resin produced by azeotropy with cyclohexane reached 10%. Stirring was performed constantly at a rotation speed of 350 rpm. After completion of the reaction, the cyclohexane phase was separated by decantation. Subsequently, water was removed from the obtained water-containing polymer particles by drying under reduced pressure until the water content became 5%, whereby water-absorbing resin 5 was obtained.

<< Examples 1-3 >>
The water-absorbing resins 1, 2 and 3 obtained in Reference Examples 5 to 7 were uniformly sprayed on a paper sheet having a basis weight of 15 g / m ² so as to have a basis weight of 90 g / m ² . After spraying, the water-absorbent resin was moistened using a mist sprayer, and then pressure-bonded with another paper sheet having a basis weight of 15 g / m ² to obtain an absorber. The obtained absorbent body was cut into 4 cm × 4 cm, and the amount of blood absorbed was measured. It can be seen that the absorber has excellent blood absorbability as shown in Table-1.
Example 4
The water absorbent resin 1 obtained in Reference Example 5 was uniformly sprayed on a paper sheet having a basis weight of 15 g / m ² so as to have a basis weight of 35 g / m ² . After spraying, the water-absorbent resin was moistened using a mist sprayer, and then pressed with another paper sheet having a basis weight of 15 g / m ² to obtain an absorbent body. The obtained absorbent body was cut into 4 cm × 4 cm, and the amount of blood absorbed was measured. It can be seen that the absorber has excellent blood absorbability as shown in Table-1.

<< Comparative Example 1 >>
^Two paper sheets having a basis weight of 15 g / m ² were stacked and cut into 4 cm × 4 cm, and the blood absorption was measured.
<< Comparative Example 2 >>
Instead of the water absorbent resin obtained in Reference Examples 5, 6 and 7, an absorbent body was prepared in the same manner as in Examples 1 to 3 except that the water absorbent resin 4 obtained in Reference Example 8 was used. The blood absorption was measured. Although this absorbent body was excellent in blood absorbability, the resin brown was visible on the surface.
<< Comparative Example 3 >>
Instead of the water absorbent resin obtained in Reference Examples 5, 6 and 7, an absorbent body was prepared in the same manner as in Examples 1 and 2 except that the water absorbent resin 5 obtained in Reference Example 9 was used. The blood absorption was measured.

Example 5
A lead-cooking paper (manufactured by Lion Co., Ltd.) was cut into 10 cm × 20 cm, three sheets were stacked, kneaded with two tissues, and pressed at 5 kg / cm ² to prepare a sheet. An absorbent body was prepared by uniformly spraying the water-absorbent resin 1 so as to have a basis weight of 180 g / m ² between the second sheet and the third sheet. A sanitary napkin was prepared by laminating a 10 cm × 20 cm liquid-permeable porous polyethylene sheet on the absorbent body, laying a polyethylene sheet underneath and adhering the periphery. 4g of equine defibrinated blood was added from the center and allowed to absorb for 3 minutes. 5 sheets of 20 cm diameter filter papers were placed on a sanitary napkin after blood absorption, and a 5 kg weight of the same diameter was placed on the sanitary napkin for 5 minutes. After 5 minutes, the filter paper was observed for blood return. As a result, no blood adhered to the filter paper.

Example 6
In Example 1, the absorbent body using the water-absorbent resin 1 was rubbed with a liquid-permeable sheet made of nonwoven fabric and a liquid-impermeable sheet made of polyethylene, and the drip absorbent sheet was created by sealing the periphery. The drip absorbent sheet showed excellent blood absorbability.

Claims (4)

An absorbent resin comprising a copolymer of a vinyl polymer (A) having a carboxyl group and an unsaturated bond and having a number average molecular weight of 500 to 50,000 and (meth) acrylic acid (B) as a constituent component An absorber comprising. (Meth) acrylic acid (B) is used in combination with a monomer having two or more ethylenically unsaturated bonds or a compound having two or more functional groups that react with the carboxyl group of (meth) acrylic acid (B) The absorbent body according to claim 1. An aqueous solution containing (meth) acrylic acid (B), an anionic surfactant, and a radical polymerization initiator is sequentially supplied into a hydrophobic organic solvent containing the nonionic surfactant. Water-in-oil type reverse-phase suspension polymerization is performed, then an aqueous solution containing the vinyl polymer (A) is supplied, water-in-oil type reverse-phase suspension polymerization is performed, and the resulting polymer slurry is dried. The absorber according to claim 1 or 2. The blood absorptive article comprised from the absorber of any one of Claims 1-3, and a liquid-permeable sheet.