JP6105947B2 - Water retention aid and absorbent material, absorbent body and absorbent article containing the same - Google Patents

Description

  The present invention relates to a novel water retention aid and an absorbent material, absorbent body and absorbent article containing the same.

  For example, for absorbent articles such as disposable paper diapers and sanitary napkins, absorbent bodies for absorbing excrement, body fluids and the like are used. The absorbent body is generally composed of an absorbent material and a water-permeable member (pulp fiber or the like) that holds the absorbent material. As the absorbent material, a highly water-absorbing polymer is frequently used.

  However, the superabsorbent polymer has the ability to absorb and retain water several tens to several thousand times its own weight, but it has sufficient water retention for liquids containing a large amount of ions such as urine. is not. For this reason, in order to raise water retention, the method of using thickeners, such as polysaccharide, together is proposed.

  For example, “an absorbent material obtained by mixing these two components with one or two or more substances selected from guar gum, alginate, and xanthan gum as other components” Known (Patent Document 1).

  Also, for example, “a body fluid that contains a polysaccharide that can thicken in the presence of a polyvalent metal ion, and that the polysaccharide is present in a state where it can be dissolved or dissociated in the water in the body fluid or excreta, or An excrement thickened article ”is known (Patent Documents 2 and 3).

JP 52-59651 A JP 2000-201976 JP 2010-148923

  However, in these prior arts, there is a problem that the absorption rate clearly decreases from the time of starting absorption, and that it decreases more remarkably with the passage of time. On the other hand, if the physical properties of the thickener or the addition amount thereof are changed in order to suppress the decrease in the absorption rate, there arises a problem that sufficient water retention cannot be obtained.

  Accordingly, an object of the present invention is to provide a water retention aid capable of expressing excellent water retention while suppressing a significant decrease in absorption rate. Furthermore, this invention aims at providing the absorber and absorber which contain the said water retention aid.

  As a result of intensive studies in view of the problems of the prior art, the present inventor has found that the above object can be achieved by employing a composition containing a specific component, and has completed the present invention.

That is, the present invention relates to the following water retention aids and absorbent materials, absorbent bodies and absorbent articles containing the same.
1. A water retention aid contained in an absorber for absorbing liquid,
(1) The water retention aid contains particles containing xanthan gum and guar gum having a weight average molecular weight (Mw) of 2700000 Daltons or more,
(2) containing 0.6 to 10 parts by weight of the xanthan gum with respect to 100 parts by weight of the guar gum;
(3) Ri Der strength of the particles 4000 g / mm ² or more,
(4) The particle is a granulated product formed by bonding particles of guar gum powder with xanthan gum,
(5) The average particle diameter of the particles is 160 to 850 μm.
A water retention aid characterized by that.
2. The particle size distribution of the particles is 0 to 10% by weight of particles having a particle size of less than 160 μm, 90 to 100% by weight of particles having a particle size of 160 to 850 μm, and 0 to 10% by weight of particles having a particle size of more than 850 μm. The water retention aid according to Item 1, wherein
3. Item 3. An absorbent comprising the water retention aid according to Item 1 or 2 and a water absorbent material.
4). Item 4. The absorbent according to Item 3 , wherein 1 to 10 parts by weight of the water retention aid according to Item 1 or 2 is contained with respect to 100 parts by weight of the water-absorbing material.
5. An absorbent comprising the water retention aid according to item 1 or 2 .
6). Item 6. The absorbent body according to Item 5 , having 1) a region containing a water retention aid and not containing a water absorbing material, and 2) a region not containing a water retention aid and containing a water absorption material.
7). The absorbent article containing the absorber of said claim | item 5 or 6 .
8). Item 8. The absorbent article according to Item 7, which is used for absorbing human or animal body fluids, blood, excrement or secretions.
9. Item 2. The method for producing a water retention aid according to Item 1, comprising a step of granulating a raw material powder containing guar gum powder in the presence of a solution in which xanthan gum is dissolved in a solvent .
10. A method for producing a multilayer structure including a water retention aid and an absorbent material, comprising 1) a step of placing the water retention aid and / or the water absorbent material on the water permeable member, and 2) a water permeable member from above Item 6. The method for producing an absorbent body according to Item 5, wherein a series of steps including a step of laminating one layer or two or more layers is performed once or more .

  ADVANTAGE OF THE INVENTION According to this invention, the water retention auxiliary | assistance which exhibits the outstanding water retention property can be provided, suppressing the fall of the remarkable absorption rate. In particular, in the present invention, after determining that one of the causes of the decrease in the absorption rate is the disintegration / dissolution of the water retention aid particles during use, xanthan gum is substantially used as a binder, and specific guar gum particles are used. A granulated product (granule) having a high particle strength prepared by firmly bonding and aggregating each other is employed as a water retention aid.

  Water retention aids having such characteristics are absorbent articles for absorbing liquids (especially water or liquids using the same, such as body fluids of humans, animals, blood, excrement, secretions, etc.) It is suitable for uses such as disposable paper diapers, sanitary napkins, cloth diaper liners, panty liners, incontinence pads, surgical blood absorbents and the like.

FIGS. 1A and 1B are schematic views illustrating a procedure for producing an absorber in Example 1. FIG. Fig.1 (a) shows the state before laminating a water-permeable member from the top. FIG.1 (b) shows the state which laminated | stacked the water-permeable member. FIGS. 2A and 2B are schematic diagrams showing the layer structure of the multilayer structure and the absorber made of the multilayer structure manufactured in Example 1. FIG. Fig.2 (a) shows the laminated body before pressing. FIG.2 (b) shows the absorber obtained by pressing a laminated body. 3 (a) and 3 (b) are schematic views showing a procedure for producing an absorber in Comparative Example 1. FIG. Fig.3 (a) shows the state before laminating a water-permeable member from the top. FIG.3 (b) shows the state which laminated | stacked the water-permeable member. 4A and 4B are schematic views showing the layer structure of the multilayer body and the absorber made of the multilayer structure manufactured in Comparative Example 1. FIG. Fig.4 (a) shows the laminated body before pressing. FIG.4 (b) shows the absorber obtained by pressing a laminated body. Fig.5 (a)-(c) is a schematic diagram which shows the specific example of the planar structure of the absorber of this invention.

1. Water retention aid and method for producing the same (1) Water retention aid The water retention aid of the present invention (hereinafter also referred to as "water retention aid of the present invention") is a water retention aid contained in an absorbent for absorbing liquid. And
(1) The water retention aid contains particles containing xanthan gum and guar gum (hereinafter simply referred to as “guar gum”) having a weight average molecular weight (Mw) of 2700000 Daltons or more,
(2) containing 0.6 to 10 parts by weight of the xanthan gum with respect to 100 parts by weight of the guar gum;
(3) The strength of the particles is 4000 g / mm ² or more.
It is characterized by that.

  The water retention aid of the present invention contains particles containing guar gum and xanthan gum. The proportion of the total amount of guar gum and xanthan gum in the water retention aid of the present invention is not particularly limited, but is usually 80 to 100% by weight, particularly 95 to 100% by weight, more preferably substantially 100% by weight. .

  The water retention aid of the present invention preferably contains guar gum and xanthan gum in one particle. In particular, it is preferable that both components are uniformly distributed in one particle. By adopting such a configuration, a high particle strength can be obtained more reliably.

  The guar gum used in the present invention has a weight average molecular weight (Mw) of 270,000 Daltons or more, preferably 2700000 to 3300000 Daltons. By using guar gum within such a range, excellent water retention and the like can be obtained. A known or commercially available guar gum itself having such a weight average molecular weight can be used. Moreover, as for a guar gum, it is desirable for the absorptivity shown in the below-mentioned Example to be 25 g / g or more, especially 25 g / g-40 g / g. Even better water retention can be obtained by setting to such a range.

  The xanthan gum is not particularly limited in its type (molecular weight, molecular structure, etc.), production method (synthesis conditions, medium, origin, etc.), and any known or commercially available one can be used.

  The content ratio of guar gum and xanthan gum is not particularly limited as long as the above-mentioned predetermined particle strength can be obtained, but usually 0.6 to 10 parts by weight of xanthan gum with respect to 100 parts by weight of guar gum, and particularly with respect to 100 parts by weight of guar gum. Xanthan gum is preferably 1 to 5 parts by weight. By setting within the above range, high particle strength and the like can be obtained more reliably.

  The particles may contain other components within a range that does not hinder the effects of the present invention. For example, polysaccharides other than guar gum and xanthan gum (for example, glucomannan, carrageenan, locust bean gum, tamarind seed polysaccharide, pullulan, etc.), cellulose compounds (for example, hydroxypropylcellulose, ethylcellulose, carboxymethylcellulose, crystalline cellulose, methylcellulose, etc.) In addition, known additives such as antibacterial agents, adsorbents, pH adjusters, stabilizers, anti-inflammatory agents, coloring agents, and fragrances can be used. These other components may be contained in the particles, but some or all of them may be present outside the particles. In particular, these other components are also preferably contained in the particles.

Particle strength of the particles in the present invention water retention aids 4000 g / mm ² or more, preferably 7000 g / mm ² or more. By having such extremely high particle strength, it is possible to effectively suppress or prevent the disintegration / dissolution of particles during use, and as a result, excellent water retention can be obtained while suppressing a significant decrease in absorption rate. . The upper limit of the particle strength is not particularly limited, but is preferably about 16000 g / mm ² from the viewpoint of obtaining the above effect more reliably.

  Although the form of the water retention aid of the present invention is not particularly limited, it is generally desirable to provide it in the form of granules (powder). In the case of granules, the particle size can be appropriately changed, but usually the particle size distribution is 0 to 10% by weight of particles having a particle size of less than 160 μm, and 90 to 100% by weight of particles having a particle size of 160 to 850 μm. It is desirable that the particle size exceeding 850 μm is 0 to 10% by weight. In particular, the particles having a particle diameter of less than 180 μm are 0 to 10% by weight, the particles having a particle diameter of 180 to 850 μm are 90 to 100% by weight, and the particles having a particle diameter exceeding 850 μm are 0 to 10% by weight. desirable. Moreover, although an average particle diameter is not limited, it is preferable to set it as about 160-850 micrometers, especially 200-850 micrometers.

  In particular, in the water retention aid of the present invention, the particles are preferably a granulated product formed by bonding particles of guar gum powder with xanthan gum. That is, xanthan gum plays a role as a binder (binder), and part of the particles of guar gum powder dissolves, so that another guar gum particle is passed through a xanthan gum solution (aqueous solution) covering a part or all of the surface of the guar gum particle. As a result of repeating the phenomenon of bonding, it is considered that a predetermined granulated product is obtained. Therefore, for example, a granulated product obtained by granulating a raw material powder containing guar gum powder in the presence of a solution in which xanthan gum is dissolved in a solvent can be suitably used as the water retention aid of the present invention. In this case, the raw material powder may or may not contain xanthan gum powder. These manufacturing methods will be described in detail in (2) below. By having the particle structure as described above, it is possible to more surely realize the extremely high particle strength as described above.

  The water retention aid of the present invention is used in an absorber for absorbing liquid. For example, it can be suitably used for absorbent articles for absorbing body fluids such as humans and animals, blood, excrement, secretions and the like.

(2) Method for producing water retention aid The production method for the water retention aid of the present invention is not limited, but using guar gum and xanthan gum, granulate particles containing guar gum and xanthan gum under conditions that at least xanthan gum dissolves. The water retention aid of the present invention can be suitably produced by a production method including the step of: For example, 1) a production method including a step of granulating a raw material powder containing guar gum powder in the presence of a solution in which xanthan gum is dissolved in a solvent (first method), 2) a raw material powder containing xanthan gum powder and guar gum powder On the other hand, it can be suitably produced by a production method (second method) including a step of granulating the raw material powder in the presence of a solvent capable of dissolving guar gum and xanthan gum. That is, as explained in the above (1), a granulated product (water retention aid particles) having extremely high particle strength can be suitably obtained by using xanthan gum as a binder (binder).

First Method The first method is a production method including the step of granulating a raw material powder containing guar gum powder in the presence of a solution in which xanthan gum is dissolved in a solvent as described above.

  The granulation method is not particularly limited as long as it is a method capable of carrying out the above steps, and a known method can be adopted. For example, any of a rolling granulation method, a stirring granulation method, a fluidized bed granulation method, a compression molding method, a vibration molding method, a pressure swing method, a vacuum molding method and the like may be used. The granulation can be performed using a known or commercially available granulator. Among these granulation methods, in the present invention, the granulation can be suitably performed by a rolling granulation method, a stirring granulation method, a fluidized bed granulation method, or the like.

  As described above, the granulation is desirably performed in the presence of a solution in which xanthan gum is dissolved in a solvent. For example, a method of granulating while spraying the solution on the raw material powder can be employed.

  The above solution can be prepared by dissolving xanthan gum in a solvent. The solvent is not particularly limited as long as it dissolves guar gum and xanthan gum. As such a solvent, water or an aqueous solvent can be suitably used. Examples of the aqueous solvent include a mixed solution of water and a water-soluble organic solvent (such as ethanol).

  In the present invention, it is particularly preferable to use water as a solvent. By using such a solvent, a desired high-strength granulated product can be prepared by the xanthan gum solution serving as a binder while maintaining the guar gum powder particles as a solid.

  The concentration of xanthan gum in the above solution is not particularly limited, but is usually 0.1-100 g / L, preferably 0.1-10 g / L. Moreover, it is preferable that the mixing | blending ratio of a xanthan gum solution shall be 35 weight part or more of the said solution with respect to 100 weight part (solid content) of guar gum, More preferably, it is 50-150 weight part, More preferably, it is 100-125 weight part. Use. This makes it possible to prepare a granulated product more efficiently.

  The granulation is preferably controlled so as to have the predetermined particle diameter. That is, the particle size distribution is 0 to 10% by weight of particles having a particle diameter of less than 160 μm, 90 to 100% by weight of particles having a particle diameter of 160 to 850 μm, and 0 to 10% by weight of particles having a particle diameter of more than 850 μm. It is desirable to be. In particular, the particles having a particle diameter of less than 180 μm are 0 to 10% by weight, the particles having a particle diameter of 180 to 850 μm are 90 to 100% by weight, and the particles having a particle diameter exceeding 850 μm are 0 to 10% by weight. desirable. The average particle size is preferably about 160 to 850 μm, particularly preferably 200 to 850 μm. In order to control the particle size distribution as described above, after granulation, for example, treatment such as drying, classification, coating, and the like can be performed as necessary according to a known method.

Second Method As described above, the second method is a production method including the step of granulating the raw material powder in the presence of a solvent capable of dissolving guar gum and xanthan gum with respect to the raw material powder containing xanthan gum powder and guar gum powder. .

  The granulation method may be performed in the same manner as in the first method except that a raw material powder containing xanthan gum powder and guar gum powder adjusted to a predetermined ratio is used, and a solvent capable of dissolving guar gum and xanthan gum is used as a solvent.

  As the raw material powder, a raw material powder containing xanthan gum powder and guar gum powder is used. For example, a mixed powder obtained by mixing both powders in a dry manner can be suitably used.

  As the solvent capable of dissolving guar gum and xanthan gum, for example, the same solvents as those mentioned in the first method can be used. That is, water or an aqueous solvent can be suitably used. Examples of the aqueous solvent include a mixed solution of water and a water-soluble organic solvent (such as ethanol).

2. Absorbent Material The present invention includes an absorbent material (hereinafter also referred to as “the present invention absorbent material”) comprising the water retention aid of the present invention and a water absorbent material. Therefore, this invention includes the absorptive composition containing this invention water retention aid and a water absorbing material.

  The absorbent material of the present invention includes a water-absorbing material in addition to the water retention aid of the present invention. As the water absorbing material, a water absorbing polymer can be preferably used. As the water absorbing polymer, for example, a known or commercially available high water absorbing polymer can be suitably used. More specifically, for example, polyacrylate polymer, starch-acrylate graft polymer, vinyl acetate copolymer, maleic anhydride copolymer, polyvinyl alcohol, CMC, and the like can be mentioned. These can generally be used in the form of powder, fine granules, granules, fibers and the like.

  When using a water-absorbing material, the content ratio of the water retention aid of the present invention and the water-absorbing material can be appropriately set according to the type of the water-absorbing material to be used, the desired water retention, etc. The water retention aid of the present invention is preferably 1 to 10 parts by weight, particularly 2.5 to 7.5 parts by weight, and more preferably 3 to 7 parts by weight with respect to 100 parts by weight of the water absorbent material. Within this range, even better water retention can be obtained while maintaining the desired absorption rate.

  In the absorbent material of the present invention, the water retention aid of the present invention and the absorbent material may be contained in the absorber in any form. For example, it may be a mixed powder of the powder of the water retention aid of the present invention and the powder of the absorbent material, or a granulated product obtained by granulating a material containing the water retention aid of the present invention and the absorbent material. There may be.

  As long as the effect of the present invention is not hindered, the absorbent material of the present invention may contain additives as described above as needed in addition to the water retention aid and water absorbent material of the present invention. .

3. Absorbent Body The present invention includes an absorbent body in which at least a water retention aid is held (or fixed) on a water permeable member. Therefore, as an absorbent body of the present invention, for example, 1) an absorbent body in which an absorbent material containing a water retention aid and a water absorbent material is held by a water permeable member, and 2) a material containing the water retention aid and a water absorbent material. Any of the absorbers etc. by which the material to contain is separately hold | maintained at the water-permeable member is included.

  Examples of the absorber of 1) include those in which a mixture containing a water retention aid and a water absorbing material is held (fixed) on a water permeable member. As the absorber of 2), for example, a material containing a water retention aid and a material containing a water absorbing material are held (fixed) to the water permeable member in a state of being separated by the water permeable member or other materials. And the like.

  As the water permeable member used in the absorber, a member partially or entirely made of a porous material can be suitably used. The porous material may be any material that allows water or a liquid that uses water as a solvent (medium) to pass therethrough. For example, a fibrous sheet, a porous polymer sheet, or the like can be suitably used. As a fibrous sheet, any of a nonwoven fabric, a woven fabric, etc. may be sufficient. Moreover, as a fiber which comprises a fibrous sheet, synthetic fibers other than natural fibers, such as fluff pulp, can also be used. For example, a porous synthetic resin sheet can be used as the porous polymer sheet. These can also use the material currently used by the well-known or commercially available absorber. In the present invention, a fluff pulp laminate composed of natural fibers (preferably fluff pulp) can be suitably used.

  The means for retaining the water retention aid or the like is not particularly limited, and the same method as in the case of a known or commercially available absorber can be employed. For example, a method of filling the water permeable member of the bag body with a water retention aid, a method of filling the pores (gap) of the water permeable member by pressurizing the water retention aid, etc., an adhesive or an adhesive to the water permeable member. Examples thereof include a fixing method and a method of forming after mixing a material capable of constituting a water-permeable member and a water retention aid.

  The content of the water retention aid in the absorber can be appropriately changed according to the desired water absorption and the like. However, the ratio to the water-absorbing material is particularly the above 2. It is preferable to adjust within the range indicated by.

  The structure of the absorbent body of the present invention is not particularly limited, but preferably has a multilayer structure. For example, an absorbent body having a multilayer structure including at least one layer made of a water-permeable member and a water retention aid and / or a water-absorbing material held by the member can be suitably used.

As such a multilayer structure, for example, a multilayer structure manufactured by the following method can be suitably employed.
(A) A multilayer structure including a water retention aid and an absorbent material, 1) a step of placing the water retention aid and / or the water absorbent material on the water permeable member, and 2) the top of the water permeable member. A multilayer structure obtained by a method in which a series of steps comprising a step of laminating one layer or two or more layers is carried out at least once. In addition, the arrangement | positioning density of the water retention adjuvant and / or absorbent material to arrange | position, or the density in each layer of a water-permeable member can be changed suitably. The usage-amount of the water retention auxiliary and / or absorptive material to arrange | position, and a water-permeable member can be changed suitably.
(B) A multilayer structure including a water retention aid and an absorbent material, 1) a step of placing the water retention aid and the water absorbent material on the water permeable member, and 2) one layer of the water permeable member from above Including a step of laminating two or more layers and 3) a step of disposing a water-absorbing material from above, and 4) a step of laminating one or more layers of water-permeable members from above, and 3) and / or Or the multilayer structure obtained by the method by which the process of said 4) is implemented once or more. In addition, the mixing density of the water retention aid and / or the absorbent material to be mixed or the density in each layer of the water-permeable member can be appropriately changed. The amount of the water retention aid and / or absorbent material and the water permeable member to be mixed can be appropriately changed.
(C) A multilayer structure comprising a water retention aid and an absorbent material, wherein the water retention aid and / or water absorption is applied to a layer comprising a water retention aid and / or a mixture comprising a water absorbent material and a fibrous material. A multilayer structure obtained by carrying out the step of laminating one layer or two or more layers made of a mixture containing a material and a fibrous material or at least once. In addition, the mixing density of the water retention aid and / or the absorbent material to be mixed or the density in each layer of the water-permeable member can be appropriately changed. Moreover, the weight of the water retention aid and / or the absorbent material and the water permeable member to be mixed can be appropriately changed.

  In the method (C), the fibrous material to be used is not limited as long as it is a material that can constitute the water-permeable member, and known or commercially available short fibers or long fibers can be used. More specifically, pulp (fiber) or the like can be used. As the pulp itself, known or commercially available ones can be used.

  In any of the methods (A), (B), and (C), the form of the water retention aid and the water-absorbing material is not limited. For example, any of powder, granule (granulated product), molded product, etc. Forms can also be employed. For example, as shown in Examples described later, a powder or granular water retention aid and a powder or granular water-absorbing material can be suitably used.

  In the methods (A), (B), and (C), when forming a multilayer structure, the laminate can be pressurized as necessary. As a method of pressurizing, a method using a known or commercially available press device or the like can be adopted.

  As a multilayer structure, for example, 1) When the water retention aid and / or the water absorbent material is held inside the water permeable member, 2) The water retention aid and / or the water absorbent material is held on the surface of the water permeable member. Any structure such as the case of being included is included.

  For example, 1) When each layer contains both a water retention aid and a water absorbing material, 2) a region that contains a water retention aid and does not contain a water absorbent material (a water retention aid region), and no water retention aid, This includes any case where a region containing an absorbent material (absorbent material region) coexists.

  The planar structure of the absorbent body of the present invention is not limited. For example, in the case where one layer is a layer composed of a water retention auxiliary region or a layer composed of an absorbent material region, the planar structure is shown in FIGS. As shown, the absorbent material region 72 is disposed in the center, and the water retention aid region 71 is disposed in the whole or a part of the periphery of the absorbent material region (both ends in the longitudinal direction or the short direction). A planar structure may be used.

  By making the structure of the absorber of the present invention a multi-layer structure, the water retention effect is enhanced by arranging at least the water retention aid close to each other, and it is possible to efficiently reduce rewetting. In addition, since the swelling due to the place is easily averaged, it is possible to obtain an effect that the thickness of the absorbent body as a whole is difficult to be uneven.

4). Absorbent article TECHNICAL FIELD This invention includes the absorbent article (product) containing an absorber. The absorbent article of the present invention can employ a known configuration except that the absorbent body of the present invention is used as the absorbent body. Moreover, these absorbent articles can be manufactured (assembled) by a known method according to the type of each article. As specific examples of the absorbent article, for example, 1) a liquid-permeable sheet located on the skin contact surface side of the wearer, 2) a liquid-impermeable sheet located on the non-skin contact surface side of the wearer, and 3) Examples include an absorbent article including an absorber disposed between the liquid-permeable sheet and the liquid-impermeable sheet.

  As the liquid permeable sheet, those used in known or commercially available absorbent articles can be used. For example, a sheet-like material having a structure that allows liquid to permeate, such as an apertured film, a woven fabric, and a non-woven fabric. The fibers constituting the woven fabric and the nonwoven fabric may be either natural fibers or chemical fibers. Examples of natural fibers include cellulose such as pulverized pulp and cotton. Examples of the chemical fiber include regenerated cellulose such as rayon and fibril rayon; semi-synthetic cellulose such as acetate and triacetate; thermoplastic hydrophobic chemical fiber and thermoplastic hydrophobic chemical fiber subjected to hydrophilic treatment. Examples of the thermoplastic hydrophobic chemical fiber include fibers made of a graft polymer of PE and PP in addition to single fibers such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). Examples of the nonwoven fabric include air-through nonwoven fabric, spunbond nonwoven fabric, point bond nonwoven fabric, spunlace nonwoven fabric, needle punched nonwoven fabric, melt blown nonwoven fabric, and nonwoven fabrics composed of these combinations (for example, SMS).

The liquid-impermeable sheet may be any sheet that does not allow liquid to pass through, but is preferably one that allows gas to pass through. For example, a film containing PE, PP or the like; a resin film having air permeability; a resin film having air permeability bonded to a nonwoven fabric such as spunbond or spunlace; and a multilayer nonwoven fabric such as SMS. Considering the flexibility of the absorbent article, for example, a low density polyethylene (LDPE) film having a basis weight of about 15 to about 30 g / m ² is preferable.

  If necessary, a second sheet can be included as a separate layer between the liquid-permeable sheet and the absorber. As the second sheet, the same sheet as the liquid permeable sheet can be used.

  Moreover, the whole or a part of the absorber contained in the absorbent article may be covered with a layer (so-called core wrap) having a barrier property that is liquid-permeable and does not transmit the absorbent. For example, a woven fabric or a non-woven fabric can be used as the layer. Examples of the woven fabric and non-woven fabric include natural fibers, chemical fibers, and tissue paper.

Examples of the use of the absorbent article of the present invention include the same uses as known or commercially available absorbent articles. For example, it can be applied to disposable paper diapers, sanitary napkins, cloth diaper liners, panty liners, incontinence pads, surgical blood absorbing materials, and the like.

  The features of the present invention will be described more specifically with reference to the following examples and comparative examples. However, the scope of the present invention is not limited to the examples.

  In addition, each test in each Example and a comparative example was implemented with the following method.

1) Measurement of average particle diameter JIS standard sieve opening of 710 μm (22 mesh), opening of 500 μm (30 mesh), opening of 425 μm by automatic dry sonic sieving measuring instrument (“ROBOT SIFTER RPS-105” manufactured by Seishin Co. (36 mesh), opening 355 μm (42 mesh), opening 300 μm (50 mesh), opening 250 μm (60 mesh), opening 180 μm (83 mesh), opening 106 μm (140 mesh) The particle size distribution was measured by sieving for minutes. And the integrated 50 mass% particle diameter in sieving integrated distribution was made into the average particle diameter.

2) Measurement of particle strength After classifying a sample with a JIS standard sieve and measuring the strength of each of the 30 particles approximated to the average particle size with a particle strength measuring device GRANO (Okada Seiko Co., Ltd.), The average of the measurement results for 20 pieces excluding 5 pieces at the top and bottom was taken as the intensity of each piece.

3) Measurement of absorption ratio a) 0.25 g of a sample is put in a nylon mesh bag and weighed.
b) Place 50 g of artificial urine in a 100 mL beaker.
c) The nylon mesh bag containing 0.25 g of the sample was placed in a 100 mL beaker containing 50 g of artificial urine, and the weight of the entire nylon mesh bag after being left for 30 minutes was measured, and the absorption capacity was determined by the following formula. .
Absorption capacity = (weight of the whole nylon mesh bag of c−weight of the whole nylon mesh bag of a) / weight of the sample (0.25 g)

4) Measurement of absorption time a) A superabsorbent polymer (Sumitomo Seika Co., Ltd., trade name “Aquakeep SA55SXII”) 1.0 g and a sample 0.05 g are placed on one half of a petri dish (outer diameter 90 mm, height 15 mm). Add the mixture. For Comparative Example 1, only 1.0 g of a superabsorbent polymer is added.
b) Tilt the petri dish slightly so that the superabsorbent polymer and the sample are on top, and pipette 10 mL of artificial urine on the opposite side of the superabsorbent polymer and the sample.
c) Tilt the petri dish and allow the liquid to flow along the side of the petri dish to the superabsorbent polymer and the sample side and simultaneously start time measurement.
d) While tilting the petri dish, the fluidity of the liquid is confirmed, and the point at which no fluid flow is observed is taken as the end point.
e) b to d were performed at 5-minute intervals, the absorption time was measured in the same manner, and the total of 3 cycles was taken as the absorption time.

5) Measurement of the water retention amount of the absorbent body a) The weight of the absorbent body and the weight of the nylon mesh bag are measured.
b) Place the absorber in a nylon mesh bag.
c) 240 mL of artificial urine is dropped into the absorber.
d) The absorbent is immersed in a vat containing 300 mL of physiological saline and left for 30 minutes.
e) The immersed absorbent body was put in a centrifugal dehydrator, and the weight (including the bag) of the absorbent body after dehydration at 75 G for 90 seconds was measured, and the water retention amount was determined by the following formula.
Water retention amount = weight of absorbent after dehydration (including bag)-(weight of absorbent before testing + weight of nylon mesh bag)

6) Preparation of artificial urine for use in each test Urea 2 w / v. % Sodium chloride 0.8 w / v. %, Magnesium sulfate 0.08 w / v. %, Calcium chloride 0.03 w / v. % Aqueous solution was prepared and used as artificial urine.

7) Molecular weight measurement The sample was adjusted to 1 mg / mL by adding water, and then centrifuged at 15000 rpm for 2 min. Thereafter, the weight average molecular weight (Mw) of the solution treated with the 0.2 μm filter was measured with Viscotek TDAmax + GPCmax (manufactured by Malvern) under the following conditions.
Mobile phase: 0.1M NaNO ₃ + 0.02% NaN ₃
Column: 2 × A6000M (Malvern)
Standard: GPC / SEC Standards Kit, Polyethylene Oxide (PEO) (Malvern, 19 kDaltons)
Temperature: 35 ° C
Flow rate: 0.7 mL / min
Sample concentration: 1 mg / mL
Injection volume: 100μL

8) Viscosity measurement 199 g of purified water was put into a 300 mL tall beaker, and 1 g of a sample was gradually added while stirring at 500 rpm, and then stirred for 14 hours. The viscosity of this solution was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd.) at a liquid temperature of 13 ° C., an M2 rotor, and 30 rpm.

Example 1
After loading 100 parts by weight of a commercially available guar gum having a weight average molecular weight (Mw) of 306,000 Daltons and an absorption ratio of 26 g / g into a high speed mixer (manufactured by Fukae Pautech), a commercially available xanthan gum 1 having a viscosity of 400 to 500 mPa · s as a binder. Granulation was carried out using a whole amount of a part dissolved in 100 parts by weight of purified water as a solvent. After the obtained granulated product was dried at 60 ° C., the particle size was classified to 180 to 750 μm, thereby producing a water retention aid comprising granules having an average particle size of 400 μm. The weight retention molecular weight (Mw) of the water retention aid was 2840000 Daltons. Next, 7.56 g of an absorbent was prepared by mixing 0.36 g of the obtained water retention aid with a superabsorbent polymer (Sumitomo Seika Co., Ltd., trade name “Aquakeep SA55SXII”). Next, the absorbent material (7.56 g) was divided into four equal parts, and an absorbent body was produced according to the procedure shown in FIG. That is, the absorbent material (1.89 g) obtained by dividing the absorbent material composed of the highly water-absorbing polymer particles 3 and the water retention aid particles 4 into four equal parts is obtained as shown in FIG. Pulp laminate; basis weight 50 g / m ² , size 30 cm × 10 cm, weight of 1.5 g per sheet) was uniformly sprinkled over, and then the pulp layer 5 was placed from above as shown in FIG. . By repeating the steps shown in FIGS. 1A and 1B four times, “pulp layer / absorbent layer / pulp layer / absorbent layer / pulp layer / absorption as shown in FIG. A laminate 6 composed of “material layer / pulp layer / absorbent layer / pulp layer” was produced. Thereafter, the laminate 6 is pressed under the conditions of a press pressure of 80 kg / cm ² , a press temperature of room temperature, and a press time of 10 to 15 seconds × 4 times. The absorbent body 7 (15.06 g) in which the highly water-absorbing polymer particles 3 and the water retention aid particles 4 constituting the structure were held in the pulp layer 5 was obtained.

Comparative Example 1
Only 7.56 g of the superabsorbent polymer similar to Example 1 was used as the absorbent. This was divided into four equal parts, and an absorber was produced according to the procedure shown in FIG. That is, the absorbent material (1.89 g) obtained by dividing the absorbent material composed of the highly water-absorbent polymer particles 3 into four equal parts as shown in FIG. 3 (a) is a pulp layer 5 (fluff pulp laminate; basis weight) as a water-permeable member. 50 g / m ² , size 30 cm × 10 cm, weight of 1.5 g per sheet), and then the pulp layer 5 was placed from above as shown in FIG. By repeating the process shown in FIGS. 3A and 3B four times, “pulp layer / absorbent layer / pulp layer / absorbent layer / pulp layer / absorbent layer / shown in FIG. A laminate 10 composed of “pulp layer / absorbent layer / pulp layer” was produced. Thereafter, the laminate is pressed under the conditions of a pressing pressure of 80 kg / cm ² , a pressing temperature of room temperature, and a pressing time of 10 to 15 seconds × 4 times, thereby forming an absorbent material as shown in FIG. Thus, an absorbent body 11 (15.06 g) in which the superabsorbent polymer particles 3 to be held in the pulp layer 5 was obtained.

Comparative Example 2
Example 1 except that 0.36 g of a commercially available guar gum powder similar to Example 1 was mixed with a superabsorbent polymer similar to Example 1 in place of the water retention aid, except that 7.56 g of the absorbent was prepared. An absorber was prepared in the same manner as described above.

Comparative Example 3
100 parts by weight of commercially available guar gum similar to Example 1 and 3 parts by weight of commercially available hydroxypropylcellulose as a binder were loaded into a high speed mixer (Fukae Pautech Co., Ltd.), and then 40 parts by weight of ethanol was used as a solvent. Granulation was performed. After drying this at 40 degreeC, the particle diameter was classified into 180-750 micrometers, and the water retention auxiliary agent which consists of a granule with an average particle diameter of 300 micrometers was manufactured. Next, an absorbent body was prepared in the same manner as in Example 1 except that 0.36 g of the obtained water retention aid was mixed with the same superabsorbent polymer as in Example 1 to prepare 7.56 g of an absorbent. did.

Test example 1
About the water retention aid and the absorbent obtained in Example 1 and Comparative Examples 1 to 3, the particle strength and average particle diameter of the water retention aid, the absorption ratio (after 30 minutes), the absorption rate (total absorption time of 3 cycles) ) And the amount of water retained in the absorber. The results are shown in Table 1.

  As is clear from the results in Table 1, it can be seen that the water retention of Example 1 is superior to that of Comparative Example 1. That is, in Example 1, after absorbing a large amount of liquid, even if time passes, it turns out that it is hold | maintained in an absorber, without discharging | emitting water. Further, as can be seen from the results of the absorption rates of Comparative Examples 2 to 3, the water retention aid generally decreases when the water retention is increased, whereas the water retention aid of Example 1 does not cause such a decrease phenomenon. It can be seen that the same absorption rate as in Comparative Example 1 is maintained. Further, when the particle strengths of Example 1 and Comparative Example 3 are compared, the water retention aid of Example 1 has a higher particle strength than Comparative Example 3, and this suppresses a decrease in absorption rate. Conceivable. Thus, by using the water retention aid of the present invention, it is possible to provide an absorbent body having excellent water retention without lowering the absorption rate.

Example 2
A water retention aid, an absorbent material and an absorber were produced in the same manner as in Example 1 except that the particle size of the water retention aid was classified to 500 to 850 μm.

Example 3
A water retention aid, an absorbent material and an absorber were produced in the same manner as in Example 1 except that the particle size of the water retention aid was classified to 355 to 500 μm.

Example 4
A water retention aid, an absorbent material and an absorber were prepared in the same manner as in Example 1 except that the particle size of the water retention aid was classified to 250 to 355 μm.

Comparative Example 4
A water retention aid, an absorbent material and an absorbent body were produced in the same manner as in Example 1 except that the particle size of the water retention aid was classified to 150 μm or less.

Test example 2
The test was carried out in the same manner as in Test Example 1 for the water retention aid and the absorbent obtained in Examples 2 to 4 and Comparative Example 4. The results are shown in Table 2.

As is clear from the results in Table 2, it can be seen that Examples 2 to 4 exhibit superior water retention compared to Comparative Example 4. That is, in these examples, after absorbing a large amount of liquid, the water retention when time passes is excellent. Moreover, it turns out that the absorption rate falls in Comparative Example 4, whereas the water retention aids of Examples 2 to 4 do not cause such a reduction phenomenon. Therefore, in this invention, it can be said that the optimal particle | grain intensity | strength which can exhibit the outstanding water retention and water absorption, without reducing an absorption rate is about 4000-16000g / mm < ² >.

Example 5
A water retention aid, an absorbent and an absorber were prepared in the same manner as in Example 1 except that 1.5 parts by weight of the commercially available xanthan gum similar to that in Example 1 was used as the binder.

Example 6
A water retention aid, an absorbent material and an absorbent were prepared in the same manner as in Example 1 except that 3 parts by weight of the commercially available xanthan gum similar to that in Example 1 was used as the binder.

Example 7
A water retention aid, an absorbent material and an absorbent were prepared in the same manner as in Example 1 except that 5 parts by weight of the commercially available xanthan gum similar to that in Example 1 was used as the binder.

Comparative Example 5
A water retention aid, an absorbent material and an absorbent were prepared in the same manner as in Example 1 except that 0.5 parts by weight of the commercially available xanthan gum similar to that in Example 1 was used as a binder.

Test example 3
Tests were carried out in the same manner as in Test Example 1 for the water retention aids and absorbers obtained in Examples 5 to 7 and Comparative Example 5. The results are shown in Table 3.

  As is clear from the results in Table 3, the water retention of Examples 5 to 7 exhibits superior performance as compared with Comparative Example 5. That is, in these examples, it can be seen that the water retention when time passes after absorbing a large amount of liquid is excellent. In general, when the water retention is increased, the absorption rate tends to decrease, whereas in Examples 5 to 7, it is understood that there is no such decrease phenomenon. Therefore, in the present invention, the optimum xanthan gum content for obtaining a water retention aid capable of exhibiting better water retention without lowering the absorption rate is 0.6% by weight with respect to 100 parts by weight of guar gum. It can be said that it is more than a part.

Example 8
A water retention aid, an absorbent material and an absorber were prepared in the same manner as in Example 1 except that a commercially available xanthan gum having a viscosity of 700 to 800 mPa · s was used as a binder.

Comparative Example 6
A water retention aid in the same manner as in Example 1, except that a commercially available guar gum having a weight average molecular weight (Mw) of 2600000 Daltons and an absorption ratio of 15 g / g, and a commercially available xanthan gum having a viscosity of 700 to 800 mPa · s as a binder, Absorbents and absorbers were prepared.

Comparative Example 7
A water retention aid, absorbent material and absorber were prepared in the same manner as in Example 1 except that a commercially available guar gum having a weight average molecular weight (Mw) of 2600000 Daltons and an absorption ratio of 15 g / g was used.

Test example 4
Tests were conducted in the same manner as in Test Example 1 for the water retention aids and absorbent bodies obtained in Example 8 and Comparative Examples 6-7. The results are shown in Table 4.

  As is clear from the results in Table 4, it can be seen that the water absorption capacity and water retention of Examples 1 and 8 are superior to those of Comparative Examples 6-7. That is, in Example 8, it is understood that the water retaining property is excellent when time passes after absorbing a large amount of liquid. In general, when the water retention is increased, the absorption rate is decreased, whereas in Examples 1 and 8, such a decrease is not observed from the results of the absorption time. Therefore, in the present invention, especially as the guar gum, the weight average molecular weight (Mw) is set to 2700000 Daltons or more, more preferably 2700000 to 3300000 Daltons, and the absorption capacity is set to 25 g / g or more, more preferably 25 g / g to 40 g / g. Thus, it can be seen that a better water retention can be obtained, and in particular, the xanthan gum of the binder is not limited.

Example 9
100 parts by weight of commercially available guar gum similar to Example 1 and 1 part by weight of commercially available xanthan gum similar to Example 1 as a binder were loaded into a high speed mixer (Fukae Pautech Co., Ltd.), and then 100 parts by weight of purified water as a solvent. Used to granulate. After drying this at 60 ° C., the particle size was classified to 180 to 750 μm, thereby producing a water retention aid comprising granules having an average particle size of 400 μm. Next, an absorbent body was prepared in the same manner as in Example 1 except that 0.36 g of the obtained water retention aid was mixed with the same superabsorbent polymer as in Example 1 to prepare 7.56 g of an absorbent. did.

Test Example 5
The test was carried out in the same manner as in Test Example 1 for the water retention aid and the absorbent obtained in Example 9 and Comparative Example 1. The results are shown in Table 5.

  As is clear from the results in Table 5, it can be seen that the water retention of Example 9 is superior to that of Comparative Example 1. That is, in this example, it can be seen that the water retention is excellent when time passes after absorbing a large amount of liquid. In general, when the water retention is increased, the absorption rate decreases, whereas in Example 9, the absorption rate does not decrease, and it is understood that the absorption rate equivalent to that of Comparative Example 1 is maintained. Therefore, in the present invention, when water retention aids are manufactured, even if granulation is performed by adding a solvent to a mixture of raw material powders of guar gum and xanthan gum in advance, xanthan gum dissolves in the solvent during the granulation process, and as a binder Since it plays a role, it turns out that desired performance can be obtained.

Example 10
A water retention aid, an absorbent material and an absorber were prepared in the same manner as in Example 1 except that 1.25 parts by weight of commercially available xanthan gum similar to Example 1 was used as the binder and 125 parts by weight of purified water was used as the solvent.

Comparative Example 8
A water retention aid, absorbent material and absorber were prepared in the same manner as in Example 1 except that 0.3 parts by weight of commercially available xanthan gum similar to Example 1 was used as the binder and 30 parts by weight of purified water was used as the solvent.

Test Example 6
The test was carried out in the same manner as in Test Example 1 for the water retention aid and the absorbent obtained in Example 10 and Comparative Example 8. The results are shown in Table 6.

  As is clear from the results in Table 6, it can be seen that the water retention of Example 1 and Example 10 is superior to that of Comparative Example 8. That is, in Example 1 and Example 10, after absorbing a lot of liquid, it turns out that it is excellent in the water retention property when time passes. In general, when the water retention is increased, the absorption rate decreases, whereas in the examples 1 and 10, such a decrease is not recognized from the results of the absorption time. Therefore, in the present invention, the optimal amount of the solvent added to obtain a water retention aid that can have better water retention without decreasing the absorption rate is 30 parts by weight or more with respect to 100 parts by weight of guar gum. It can be said that.

Comparative Example 9
Absorbents and absorbers were prepared in the same manner as in Example 1 except that commercially available mannan was used as the binder.

Test Example 7
The test was carried out in the same manner as in Test Example 1 for the water retention aid and the absorbent obtained in Example 1 and Comparative Example 9. The results are shown in Table 7.

  As is clear from the results in Table 7, it can be seen that the water retention of Example 1 expresses performance superior to that of Comparative Example 9. That is, in Example 1, after absorbing a large amount of liquid, it turns out that it is excellent in the water retention property when time passes. Thus, in the water retention aid of the present invention, it can be seen that it is effective to use xanthan gum as a binder in order to obtain desired performance.

Claims (10)

A water retention aid contained in an absorber for absorbing liquid,
(1) The water retention aid contains particles containing xanthan gum and guar gum having a weight average molecular weight (Mw) of 2700000 Daltons or more,
(2) containing 0.6 to 10 parts by weight of the xanthan gum with respect to 100 parts by weight of the guar gum;
(3) Ri Der strength of the particles 4000 g / mm ² or more,
(4) The particle is a granulated product formed by bonding particles of guar gum powder with xanthan gum,
(5) The average particle diameter of the particles is 160 to 850 μm.
A water retention aid characterized by that. The particle size distribution of the particles is 0 to 10% by weight of particles having a particle size of less than 160 μm, 90 to 100% by weight of particles having a particle size of 160 to 850 μm, and 0 to 10% by weight of particles having a particle size of more than 850 μm. The water retention aid according to claim 1, wherein An absorbent comprising the water retention aid according to claim 1 or 2 and a water absorbent material. Water retention aids according to claim 1 or 2 for the water-absorbing material 100 parts by weight is contained 1 to 10 parts by weight, the absorption material according to claim 3. An absorbent comprising the water retention aid according to claim 1 or 2 . The absorbent body according to claim 5 , comprising 1) a region containing a water retention aid and no water absorbing material, and 2) a region not containing a water retention aid and containing a water absorption material. The absorbent article containing the absorber of Claim 5 or 6 . The absorbent article according to claim 7, which is used to absorb human or animal body fluids, blood, excreta or secretions. The method for producing a water retention aid according to claim 1, comprising a step of granulating a raw material powder containing guar gum powder in the presence of a solution in which xanthan gum is dissolved in a solvent . A method for producing a multilayer structure including a water retention aid and an absorbent material, comprising 1) a step of placing the water retention aid and / or the water absorbent material on the water permeable member, and 2) a water permeable member from above The manufacturing method of the absorber of Claim 5 which implements a series of processes including the process of laminating | stacking 1 layer or 2 layers or more once .