JP2014045914A - Water absorption sheet structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water absorption sheet structure having excellent liquid diffusivity, a high liquid permeation speed and a small liquid return amount, and further preventing an offensive odor generated from a body fluid and having antibacterial and deodorant capability even in the water absorption sheet structure having very few hydrophilic fibers such as pulp or the like, and provide an absorbent article formed by using the water absorption sheet structure.SOLUTION: A water absorption sheet structure is so constructed that an absorption layer containing water absorptive resin and an adhesive is held from above and below the absorption layer by non-woven fabric. The absorption layer is a water absorption sheet structure further containing powder of quartz diorite porphyrite. An absorbent article is so constructed that the water absorption sheet structure is held by a liquid permeable sheet and a liquid impermeable sheet.

Description

  The present invention relates to a water absorbent sheet structure that can be used in the field of sanitary materials and the like. More specifically, the present invention relates to a water-absorbing sheet structure that has antibacterial and deodorizing performance, is thin, and can be suitably used for absorbent articles such as paper diapers. Furthermore, this invention relates to absorbent articles, such as a paper diaper which uses this water absorbing sheet structure.

Absorbent articles typified by paper diapers have an absorbent body that absorbs liquids such as body fluids on a flexible liquid-permeable surface sheet (top sheet) disposed on the side in contact with the body and on the opposite side in contact with the body. It has a structure sandwiched between a liquid-impermeable back sheet (back sheet) disposed.

Conventionally, from the viewpoint of design, fit to the body, convenience when carrying, etc., there has been an increasing demand for thinner absorbent articles. Furthermore, in recent years, from the viewpoint of environmental conservation, there is a growing need for a so-called eco-friendly orientation that effectively uses resources and avoids the use of natural materials that require a long period of growth, such as trees. Conventionally, as a thinning method generally used in absorbent articles, for example, reducing hydrophilic fibers such as pulverized pulp fibers of wood, which is a role of fixing a water-absorbent resin in an absorbent body There was a method of increasing the water-absorbing resin.

  Absorber using a large amount of water-absorbent resin with low bulk and low water-absorbing capacity, and a large amount of water-absorbing resin with small volume and high water-absorbing capacity. The aim was to make it thinner by reducing the material, and it was thought to be a rational improvement method. However, when considering the distribution and diffusion of liquid when actually used in absorbent articles such as disposable diapers, so-called "gel blocking phenomenon" occurs when a large amount of water-absorbing resin becomes a soft gel by absorption, The liquid diffusibility is remarkably lowered, the liquid permeation rate of the absorber is slowed, and the liquid reversion amount is increased. This “gel blocking phenomenon” means that when a dense absorbent body absorbs a liquid, the water absorbent resin existing near the surface layer absorbs the liquid, and the soft gel becomes denser near the surface layer. This is a phenomenon in which the penetration of the liquid into the absorber is hindered and the water absorbent resin inside cannot absorb the liquid efficiently.

Therefore, even if there are very few hydrophilic fibers, the basic performance (fast liquid penetration rate, sufficient liquid absorption capacity, small amount of liquid reversal, small amount of liquid leakage, shape retention, etc.) is excellent, and thinning has been achieved. As a water absorbent sheet structure, a water absorbent sheet structure having a structure in which a predetermined amount of water absorbent resin and a predetermined amount of hot melt adhesive are sandwiched between two or more hydrophilic nonwoven fabrics having a predetermined basis weight (for example, patents) Documents 1 and 2) have been proposed.

Further, in the absorbent article, there is a problem that an unpleasant odor is generated when a body fluid, particularly urine, blood, sweat or the like is absorbed. These odors are rotting odors that are produced when bacteria present in the skin and digestive tract produce enzymes that break down components of body fluids such as urea and proteins, and the components of body fluids are decomposed by the enzymes. It is believed that there is. Furthermore, in an absorbent article, when the liquid diffusibility at the time of absorbing a bodily fluid is bad, a bodily fluid will concentrate on a part and it will become easy to generate | occur | produce a decaying odor.

International Publication WO2010 / 004894 Pamphlet International Publication WO2010 / 004895 Pamphlet

  Although the water absorbent sheet structure disclosed in Patent Documents 1 and 2 is sufficiently excellent in the basic performance, there is a continuing demand for a water absorbent sheet structure having further improved performance. On the other hand, in the water absorbent sheet structure, no consideration is given to the odor generated.

  Therefore, the present invention is excellent in liquid diffusibility, has a high liquid permeation rate and a small liquid return amount, and has an odor generated from body fluids, even in a water absorbent sheet structure having very few hydrophilic fibers such as pulp. It is an object of the present invention to provide a water-absorbent sheet structure having antibacterial and deodorizing ability.

That is, the gist of the present invention is as follows.
[1] A water-absorbent sheet structure having a structure in which an absorbent layer containing a water-absorbent resin and an adhesive is sandwiched from above and below the absorbent layer by a nonwoven fabric,
A water-absorbing sheet structure further comprising a quartz diorite powder; and [2] the water-absorbing sheet structure described in [1] sandwiched between a liquid-permeable sheet and a liquid-impermeable sheet. An absorbent article.

  The water absorbent sheet structure according to the present invention is thin and excellent in liquid diffusibility, can sufficiently exhibit absorption ability such as liquid permeation rate and liquid reversal amount, and has antibacterial and deodorizing performance. There is an excellent effect. Therefore, by using the water-absorbent sheet structure according to the present invention as an absorbent body such as a disposable diaper, it is possible to provide a sanitary material that is thin and has excellent fit to the body and has antibacterial and deodorizing performance.

It is a cross-sectional schematic diagram of an example of the water absorbing sheet structure concerning this invention. It is a cross-sectional schematic diagram of another example of the water absorbing sheet structure concerning this invention. It is a cross-sectional schematic diagram of another example of the water absorbing sheet structure concerning this invention. It is a cross-sectional schematic diagram of another example of the water absorbing sheet structure concerning this invention. It is a schematic diagram which shows schematic structure of the instrument for measuring the leak test in the inclination of a water absorbing sheet structure.

  The water absorbent sheet structure according to the present invention is a water absorbent sheet structure having a structure in which an absorbent layer containing a water absorbent resin and an adhesive is sandwiched from above and below the absorbent layer by a nonwoven fabric, and the absorbent layer Is a water absorbent sheet structure characterized by further containing quartz diorite powder having antibacterial and deodorizing performance. By adopting such a structure, it is possible to realize a water-absorbent sheet structure that is thin and excellent in liquid diffusibility, excellent in absorption performance such as liquid penetration rate and liquid reversal amount, and has antibacterial and deodorant performance. It is.

In the water absorbent sheet structure according to the present invention, the absorption layer contains quartz diorite powder. Quartz diorite is a scientific name, for example, Io stones produced in the Iozan mountain range near Kanazawa City, the prefectural border between Ishikawa Prefecture and Toyama Prefecture. Quartz diorite has a large number of pores and a large surface area, so it is known that it has excellent water absorption / adsorption performance and antibacterial activity.

This quartz diorite is a mixture mainly composed of quartz, plagioclase, mica and amphibole in terms of mineral composition, and mainly in terms of chemical composition: SiO ₂ : 70 to 80% by mass, Al ₂ O. ₃ : 10 to 16% by mass, Na ₂ O + K ₂ O: 3 to 9% by mass, and FeO + Fe ₂ O ₃ : 0.2 to 2% by mass. Further, as trace components such as Mg, Ca, V, Mo, Ti, etc. Contains oxides.

  Quartz diorite does not swell like water-absorbent resin when it absorbs water. Therefore, the presence of quartz diorite powder in the same absorption layer as the water-absorbent resin, when the absorption layer absorbs liquids such as body fluids, it serves as a passage that promotes liquid diffusion, It is considered that the gel blocking phenomenon of the water absorbent resin can be alleviated.

The content ratio of the quartz diorite powder in the absorption layer is preferably in the range of 0.04 to 0.35 times, more preferably 0.05 to 0.35 times the content (mass basis) of the water absorbent resin. The range is 0.30 times. In the absorption layer, the content ratio of the quartz diorite powder is preferably 0.04 times or more from the viewpoint of serving as a passage for liquid diffusion and maintaining sufficient antibacterial and deodorizing performance. Moreover, the content ratio of the quartz diorite powder is preferably 0.35 times or less from the viewpoint of reducing the jerky feel of the resulting water-absorbent sheet structure and improving the texture.

The mass average particle size of the quartz diorite powder preferably serves as a liquid diffusion passage in the absorption layer, and reduces the jerky feel of the resulting water-absorbent sheet structure to improve the texture. It is 100-600 micrometers, More preferably, it is 150-550 micrometers, More preferably, it is 200-500 micrometers. In the present specification, the mass average particle diameter of the quartz diorite powder is a value obtained by the measurement method described in the examples described later.

  As a kind of the water-absorbent resin used in the water-absorbent sheet structure according to the present invention, a commercially available water-absorbent resin can be used, for example, a starch-acrylonitrile graft copolymer hydrolyzate, a starch-acrylic acid graft polymer Water-absorbing resins such as neutralized products, saponified products of vinyl acetate-acrylic acid ester copolymers, and cross-linked products of partially neutralized acrylic acid polymers. Among these, a cross-linked product of a partially neutralized acrylic acid polymer is preferable from an industrial viewpoint such as supply capacity and cost. Examples of the method for producing a crosslinked product of a partially neutralized acrylic acid polymer include a reverse phase suspension polymerization method and an aqueous solution polymerization method.

  The degree of neutralization of the crosslinked product of the partially neutralized acrylic acid polymer is preferably 50 mol% or more and more preferably 70 to 90 mol% from the viewpoint of increasing the osmotic pressure of the water absorbent resin and enhancing the water absorption capacity.

The content of the water-absorbent resin in the water-absorbent sheet structure is about 1 square meter of the water-absorbent sheet structure from the viewpoint of obtaining sufficient liquid absorption performance even when the water-absorbent sheet structure according to the present invention is used in an absorbent article. 100 to 1000 g (i.e. 100 to 1000 g / ^{m 2)} are preferred, more preferably 150~900g / ^{m 2,} more preferably 200 to 700 g / ^{m 2.} The content is preferably 100 g / m ² or more from the viewpoint of sufficiently exhibiting the liquid absorption performance as the water absorbent sheet structure and particularly suppressing the liquid reversal amount, and from the viewpoint of improving the liquid penetration rate, the total content Is preferably 1000 g / m ² or less.

The weight average particle diameter of the water absorbent resin is a viewpoint that prevents the dissipation of the water absorbent resin in the absorbent layer and the gel blocking phenomenon at the time of water absorption and reduces the jerky feel of the resulting water absorbent sheet structure to improve the texture. Therefore, it is preferably 100 to 600 μm, more preferably 150 to 550 μm, and further preferably 200 to 500 μm. In the present specification, the mass average particle diameter of the water-absorbent resin is a value obtained by the measurement method described in Examples described later.

The liquid absorption performance of the water absorbent sheet structure according to the present invention is affected by the water absorption performance of the water absorbent resin used. In the present specification, the water absorption rate of the water absorbent resin is evaluated as the physiological saline water absorption rate. The physiological saline water absorption rate of the water absorbent resin is preferably 1 from the viewpoint of increasing the liquid permeation rate in the water absorbent sheet structure according to the present invention and preventing liquid leakage when used in sanitary materials such as absorbent articles. It is -70 seconds, More preferably, it is 2-60 seconds, More preferably, it is 3-55 seconds. In the present specification, the physiological saline water absorption rate of the water-absorbent resin is a value obtained by the measurement method described in Examples described later.

Examples of the adhesive used in the water-absorbent sheet structure according to the present invention include rubber adhesives such as natural rubber, butyl rubber and polyisoprene; styrene-isoprene block copolymer (SIS) and styrene-butadiene block. Styrenic elastomer adhesives such as polymer (SBS), styrene-isobutylene block copolymer (SIBS), styrene-ethylene-butylene-styrene block copolymer (SEBS); ethylene-vinyl acetate copolymer (EVA) adhesion Agent: ethylene-acrylic acid copolymer copolymer adhesive such as ethylene-ethyl acrylate copolymer (EEA), ethylene-butyl acrylate copolymer (EBA); ethylene-acrylic acid copolymer (EAA) adhesive Polyamide adhesives such as copolymer nylon and dimer acid-based polyamide; Examples include polyolefin adhesives such as polyethylene, polypropylene, atactic polypropylene, and copolymerized polyolefin; polyester adhesives such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and copolymerized polyester; and acrylic adhesives. . In the present invention, the adhesive strength is strong, and it is possible to prevent the peeling of the nonwoven fabric and the dissipation of the water-absorbent resin and the quartz diorite powder in the resulting water-absorbent sheet structure, from which ethylene-vinyl acetate copolymer is adhered. Agents, styrene elastomer adhesives, polyolefin adhesives and polyester adhesives are preferred. These adhesives may be used alone or in combination of two or more.

Among the adhesives, when using a hot-melt adhesive, the melting temperature or softening point of the adhesive is sufficient to fix the water-absorbent resin and quartz diorite powder to the non-woven fabric and to thermally degrade the non-woven fabric. From the viewpoint of preventing deformation, it is preferably 50 to 180 ° C, more preferably 70 to 150 ° C.

The content ratio of the adhesive in the water absorbent sheet structure is preferably in the range of 0.05 to 2.0 times the total content (mass basis) of the water absorbent resin and the quartz diorite powder. Preferably it is the range of 0.08 to 1.5 times, More preferably, it is the range of 0.1 to 1.0 times. From the viewpoint of preventing the peeling of the nonwoven fabric and the dissipation of the water-absorbent resin and quartz diorite powder with sufficient adhesion, and improving the form retention of the water-absorbent sheet structure, the content ratio of the adhesive is preferably 0.05 times or more From the viewpoint of preventing swelling of the water-absorbent resin due to excessive adhesion and improving the liquid penetration rate and liquid leakage of the water-absorbent sheet structure, the content ratio of the adhesive is preferably 2.0 times or less.

The water absorbent sheet structure according to the present invention is mixed with water absorbent resin and quartz diorite powder in the absorbent layer between the nonwoven fabrics in such an amount that hydrophilic fibers such as pulp do not impair the effects of the present invention. Although an aspect may be sufficient, it is preferable that it is an aspect which does not contain a hydrophilic fiber substantially from a viewpoint of thickness reduction.

The water-absorbent sheet structure according to the present invention can be produced, for example, by the following method.

(A) A mixed powder of water-absorbent resin, quartz diorite powder and adhesive is uniformly spread on the non-woven fabric, and the non-woven fabric is further stacked and heat-pressed near the melting temperature of the adhesive.
(B) A mixed powder of water-absorbent resin, quartz diorite powder, and adhesive is uniformly sprayed on the nonwoven fabric and passed through a heating furnace, and fixed to such an extent that the mixed powder does not dissipate. A non-woven fabric is laminated on this and heat-pressed.
(C) Immediately after the adhesive was melt-coated on the nonwoven fabric, a mixed powder of the water-absorbent resin and quartz diorite powder was uniformly dispersed to form a layer, and the adhesive was melt-coated from above. The non-woven fabric is laminated from above so that the coated surface of the adhesive is directed to the side of the mixed powder layer, and is pressed using a roll press or the like, and heated and pressed as necessary.
(D) On the nonwoven fabric, a mixed powder of water-absorbing resin, quartz diorite powder, and adhesive is uniformly dispersed, and the nonwoven fabric is further laminated and heat embossed to heat-bond the nonwoven fabric together.

For example, by producing a water-absorbent sheet structure by the methods shown in (a) to (d), an absorbent layer containing a water-absorbent resin, quartz diorite powder and an adhesive is made of nonwoven fabric. A water-absorbing sheet structure having a structure sandwiched from above and below can be obtained. Among these methods, the methods (a), (c), and (d) are more preferable from the viewpoint of simplicity of the manufacturing method and high manufacturing efficiency. In addition, a water absorbing sheet structure can also be manufactured combining the method illustrated by (a)-(d).

Moreover, the water absorbent sheet structure according to the present invention may be appropriately mixed with additives such as a gel stabilizer.

  In the present invention, the entire surface or part of the absorbent layer of the water-absorbent sheet structure is made to absorb the liquid to be absorbed with respect to the vertical direction (the thickness direction of the sheet structure) using an appropriate air-permeable fraction layer. It can also be set as the structure divided into the primary absorption layer of the supplied side, and the secondary absorption layer of the opposite side. By adopting such a structure, the liquid absorption performance of the water absorbent sheet structure, in particular, the liquid leakage is improved.

  The air-permeable fraction layer has an appropriate air-permeability and liquid permeability, but may be any layer as long as powder such as a water absorbent resin does not substantially pass therethrough. Specifically, nets such as nets having pores made of PE and PP fibers, porous films such as performance films, sanitary papers such as tissue paper, airlaid nonwoven fabrics made of pulp / PE / PP, etc. Examples thereof include a cellulose-containing synthetic fiber nonwoven fabric or a synthetic fiber nonwoven fabric made of rayon fiber, polyolefin fiber and polyester fiber.

  The water absorbent resin ratio (mass ratio) of the primary absorbent layer / secondary absorbent layer is preferably in the range of primary absorbent layer / secondary absorbent layer = 98/2 to 20/80. The layer / secondary absorption layer is more preferably in the range of 95/5 to 25/75, and the primary absorption layer / secondary absorption layer is more preferably in the range of 90/10 to 30/70. From the viewpoint of sufficiently exhibiting the liquid absorbability of the secondary absorption layer and preventing liquid leakage, the ratio of primary absorption layer / secondary absorption layer is preferably 98 or less / 2 or more, and the liquid penetration rate is increased. And from a viewpoint of preventing the wet touch of the side which touches the body (skin) after liquid absorption, it is preferable that a primary absorption layer / secondary absorption layer is a ratio of 20 or more / 80 or less.

The water-absorbent resin of the primary absorbent layer used in the present invention is preferably selected in the above-described preferred range in consideration of the structure of each component of the water-absorbent sheet structure. Further, the water absorbent resin of the secondary absorbent layer may be the same as or different from the water absorbent resin of the primary absorbent layer.

For example, in the water absorbent sheet structure, a positive value is present between the physiological saline water absorption rate of the water absorbent resin used in the primary absorbent layer and the physiological saline water absorption rate of the water absorbent resin used in the secondary absorbent layer. Preferably there is a difference. The greater the difference, the stronger the effect of avoiding liquid stagnation in the primary absorption layer and enhancing the dry feeling and preventing liquid leakage. Specifically, (the physiological saline water absorption speed of the water absorbent resin used in the primary absorbent layer) − (the physiological saline water absorption speed of the water absorbent resin used in the secondary absorbent layer) is preferably 10 seconds or more. Yes, more preferably 15 seconds or more, and still more preferably 20 seconds or more.

The quartz diorite powder contained in the absorption layer may be contained in each of the fractionated primary absorption layer and secondary absorption layer, or may be contained only on one side.

In particular, when there is a positive difference in the saline water absorption rate of the water-absorbing resin used in the primary absorption layer and the secondary absorption layer described above, the quartz diorite powder is secondary It is preferable that it is contained in an absorption layer. This is because when the physiological saline water absorption rate of the water absorbent resin is small, the gel blocking phenomenon of the water absorbent resin tends to occur, and the liquid diffusibility in the absorbent layer tends to deteriorate. It is preferable that powder of diorite is included in the secondary absorption layer.

The water absorbent sheet structure according to the present invention has one feature in that it can be thinned, and considering the use for absorbent articles, the thickness of the water absorbent sheet structure is preferably in a dry state. Is 4 mm or less, more preferably 3 mm or less, and still more preferably 1.0 to 2.5 mm. A dry state means the state before a water absorbing sheet structure body absorbs a liquid. In the present specification, the dry thickness of the water absorbent sheet structure is a value obtained by the measurement method described in the examples described later.

Further, the water absorbent sheet structure according to the present invention has one feature in that the liquid permeation rate is fast, and considering the use for absorbent articles, the total liquid permeation rate of the water absorbent sheet structure is preferably It is 600 seconds or less, more preferably 580 seconds or less. In this specification, the total liquid permeation rate of the water-absorbent sheet structure is a value obtained by the measurement method described in Examples described later.

  Furthermore, the water absorbent sheet structure according to the present invention has one feature in that the liquid reversal amount is small, and the liquid reversal amount of the water absorbent sheet structure is preferably 12 g in consideration of use in absorbent articles. Or less, more preferably 10 g or less. In this specification, the liquid reversal amount of the water absorbent sheet structure is a value obtained by the measurement method described in the examples described later.

  Furthermore, in the water-absorbent sheet structure according to the present invention, it is preferable that leakage in the inclination of the liquid is small in consideration of use in an absorbent article. From this, the total leakage amount in the inclination of the water absorbent sheet structure is preferably 50.0 g or less, and more preferably 45.0 g or less. In this specification, the total amount of leakage due to the inclination of the water-absorbent sheet structure is a value obtained by the measurement method described in Examples described later.

As the water-absorbent sheet structure according to the present invention, one having a predetermined characteristic in the thickness in the dry state, the total liquid penetration rate, the liquid reversal amount, and the total leakage amount in the inclination is preferable.

  Furthermore, the water-absorbent sheet structure according to the present invention has a very small amount of use of a naturally-derived material, so that the above-described thickness, liquid permeation rate, and liquid reversal amount are high-performance and environmentally conscious. It is. The use ratio of the natural material is preferably 30% by mass or less, more preferably 20% by mass or less, and further preferably 15% by mass or less. The usage ratio of the natural material is calculated by dividing the total content of pulp, cotton, hemp, silk, and the like contained in a small amount in each component of the water absorbent sheet structure by the mass of the water absorbent sheet structure.

  Next, the structure of the water absorbent sheet structure according to the present invention will be described with reference to FIG. Here, FIG. 1 is an enlarged cross-sectional view schematically showing the structure of the water absorbent sheet structure according to the present invention.

  A water absorbent sheet structure 10 shown in FIG. 1 includes an absorbent layer 14 containing a water absorbent resin 12, a quartz diorite powder 13 and an adhesive 11 by nonwoven fabrics 15 and 16, above the absorbent layer. It is a structure sandwiched from below.

  Moreover, the water absorbing sheet structure shown in FIG. 2 is also an example of another form of the water absorbing sheet structure according to the present invention. FIG. 2 shows an example in which the adhesive 17 is melt-coated on the nonwoven fabrics 15 and 16.

  Furthermore, the water absorbent sheet structure shown in FIGS. 3 and 4 is also an example of another form of the water absorbent sheet structure according to the present invention. 3 and 4, the absorbent layer is fractionated into a primary absorbent layer 20 and a secondary absorbent layer 21 by the air-permeable fraction layer 19, and is sandwiched from above and below the absorbent layer by the nonwoven fabrics 15 and 16. Structure.

  The water-absorbent sheet structure according to the present invention is a flexible liquid-permeable surface sheet disposed on the side in contact with the body (skin), that is, the side to which the liquid to be absorbed is supplied when used in an absorbent article. (Top sheet) and a structure sandwiched by a liquid impermeable back sheet (back sheet) arranged on the opposite side that contacts the body (skin), that is, on the opposite side of the liquid to be absorbed. Have.

  The absorbent article according to the present invention can be obtained by sandwiching the water absorbent sheet structure according to the present invention between the liquid permeable sheet and the liquid impermeable sheet. As the liquid permeable sheet and the liquid impermeable sheet, those known in the technical field of absorbent articles can be used without particular limitation. Moreover, this absorbent article can be manufactured by a well-known method.

Examples of the absorbent article include paper diapers, light incontinence pads, sanitary napkins, pet sheets, food drip sheets, and the like.

  Hereinafter, the present invention will be described in more detail based on examples and comparative examples. However, the present invention is not limited to such examples.

  The performances of the water-absorbing resin, quartz diorite powder, and water-absorbing sheet structure were measured by the following methods.

<Saline water absorption rate of water-absorbing resin>
The water absorption rate of the water absorbent resin was measured in a room adjusted to 25 ° C. ± 1 ° C. Stir 50 ± 0.1 g of 0.9 mass% sodium chloride aqueous solution (saline) adjusted to a temperature of 25 ± 0.2 ° C. in a thermostatic water bath with a magnetic stirrer bar (without 8 mmφ × 30 mm ring). A vortex was generated at a rotational speed of 600 r / min. Water-absorbing resin 2.0 ± 0.002 g was added to the physiological saline at a time, and the time (seconds) from the addition of the water-absorbing resin to the time when the liquid level vortex converged was measured. It was set as the physiological saline water absorption speed of the water absorbent resin.

<Mass average particle size>
Unless otherwise specified, the particle size of the water-absorbent resin or quartz diorite powder was defined as the mass average particle size, and was measured as follows. As a lubricant, 0.25 g of amorphous silica (Degussa Japan Co., Ltd., Siperant 200) was mixed with 50 g of water absorbent resin or quartz diorite powder.

JIS standard sieve from above, sieve with an opening of 850 μm, sieve with an opening of 600 μm, sieve with an opening of 500 μm, sieve with an opening of 425 μm, sieve with an opening of 300 μm, sieve with an opening of 250 μm, sieve with an opening of 150 μm, and saucer Combined in the order.

  The mixture was put on the combined uppermost sieve and classified by shaking for 20 minutes using a low-tap shaker.

  After classification, the mass of the mixture remaining on each sieve is calculated as a mass percentage with respect to the total mass, and by integrating in order from the larger particle size, the integrated value of the mass percentage of the mixture remaining on the sieve opening and sieve Is plotted on a logarithmic probability paper. By connecting the plots on the probability paper with a straight line, the particle diameter corresponding to an integrated mass percentage of 50 mass% was defined as the mass average particle diameter.

<Measurement of thickness of water absorbent sheet structure>
A sample having a strip shape of 10 cm × 30 cm and cut so that the longitudinal direction is the longitudinal direction (machine direction) of the nonwoven fabric was used as a sample. Using a thickness measuring instrument (manufactured by Ozaki Mfg. Co., Ltd., model number: J-B), the left end, the center, and the right end in the longitudinal direction were measured (3 cm from the left, 3 cm from the left, 15 cm from the center, and 27 cm from the right end). The width direction measured the center part. The measured thickness was measured three times at each location and averaged. Furthermore, the values at the left end, the center, and the right end were averaged, and the values were taken as the dry thickness of the entire water absorbent sheet structure.

<Evaluation of liquid permeation rate and liquid reversal amount of water-absorbing sheet structure>
A sample having a strip shape of 10 cm × 30 cm and cut so that the longitudinal direction is the longitudinal direction (machine direction) of the nonwoven fabric was used as a sample.

  In a 10 L container, 60 g of sodium chloride, 1.8 g of calcium chloride dihydrate, 3.6 g of magnesium chloride hexahydrate and an appropriate amount of distilled water were added and completely dissolved. Next, 15 g of a 1% by mass poly (oxyethylene) isooctylphenyl ether aqueous solution was added, and distilled water was further added to adjust the mass of the entire aqueous solution to 6000 g. A test solution was prepared.

A polyethylene air-through porous liquid permeable sheet having the same size as the sample (10 × 30 cm) and a basis weight of 22 g / m ² was placed on the top of the sample (water-absorbing sheet constituting body). Further, a polyethylene liquid-impermeable sheet having the same size and basis weight as this sheet was placed under the sample to prepare a simple absorbent article. In the vicinity of the center of this absorbent article, an acrylic plate having a bottom area of 16.8 cm ² having a cylinder with an inner diameter of 1.9 cm and a height of 15 cm is placed in the center, and a weight is placed on the acrylic plate, and a total load of 780 g is applied. It was set as the state concerning a sample. While putting 50 mL of the test solution into the cylinder at a time, using a stopwatch, the time until the test solution completely penetrates into the absorbent article was measured and used as the first liquid permeation rate (second). Next, the same operation was performed after 30 minutes and 60 minutes without moving the position of the acrylic plate, and the second and third liquid penetration rates (seconds) were measured. The total number of seconds for the first to third times was taken as the total liquid penetration rate.

The acrylic plate is removed 120 minutes after the start of the first test liquid charging, and a 10 cm square filter paper (Wa (g), about 70 g) having been measured in advance near the liquid charging position on the body fluid absorbent article ( About 80 sheets), and a 5 kg weight of 10 cm × 10 cm was placed thereon. After loading for 5 minutes, the mass of the filter paper (Wb (g)) was measured, and the increased mass was taken as the reversal amount (g).
Liquid return amount (g) = Wb−Wa (g)

<Evaluation of the amount of leakage in the slope>
The amount of leakage in the inclination was performed using the apparatus shown in FIG.
As an outline, after the acrylic plate 32 is tilted and fixed using a commercially available gantry 31 for experimental equipment, the test solution is dropped onto the absorbent article 33 placed on the plate with a dropping funnel 34 from above vertically. This is a mechanism for measuring the amount of leakage with a balance 35. Detailed specifications are shown below.

The acrylic plate 32 was 45 cm in length in the direction of the inclined surface and was fixed by the gantry 31 so that the angle formed with respect to the horizontal was 45 ± 2 °. The acrylic plate 32 had a width of 100 cm and a thickness of 1 cm, and it was also possible to measure a plurality of absorbent articles 33 in parallel. Since the surface of the acrylic plate 32 was smooth, no liquid stayed or was absorbed on the plate.

A dropping funnel 34 was fixed vertically above the inclined acrylic plate 32 using the gantry 31. The dropping funnel 34 had a capacity of 100 mL, an inner diameter of the tip portion of about 4 mm, and the cock throttle was adjusted so that the liquid was introduced at 8 mL / second.

A balance 35 on which a tray 36 is placed is installed at the lower part of the acrylic plate 32. All of the test liquid that flows down as a leak is received, and its mass is recorded with an accuracy of 0.1 g.

The leak test in the inclination using such an apparatus was performed according to the following procedure. After measuring the mass of the water-absorbent sheet structure having a strip shape of 10 cm × 30 cm and having the longitudinal direction cut in the longitudinal direction (machine direction) of the nonwoven fabric, the liquid-permeable nonwoven fabric made of air-through polyethylene of the same size (weight per unit area) 22 g / m ² ) is attached from above, and a simple absorbent article 33 made by attaching a liquid impervious sheet of polyethylene of the same size and weight from below is pasted on the acrylic plate 32. (The lower end of the absorbent article 33 was not pasted on the acrylic plate 32 in order not to stop leaking).

Marks were placed at locations 2 cm below the upper end of the absorbent article 33, and the inlet of the dropping funnel 34 was fixed so that the vertical distance from the mark was 10 ± 1 mm.

After starting the balance 35 and correcting the display to zero, 80 mL of the test solution was put into the dropping funnel 34 at a time. The test liquid flowed through the inclined acrylic plate 32 without being absorbed by the absorbent article 33, and the amount of liquid entering the tray 36 was measured to obtain the first leakage amount (g).

Similarly, at the interval of 10 minutes from the start of the first injection, the second and third test solutions were similarly supplied, and the second and third leakage amounts (g) were measured. The total (g) of the first to third leakage amounts was defined as the total leakage amount in the slope.

<Tactile sensation of water absorbent sheet structure>
The tactile sensation of the water absorbent sheet structure was evaluated by the following method. The obtained water absorbing sheet structure was cut into a size of 10 × 30 cm. Ten panelists were selected, and the surface of the water-absorbing sheet structure was evaluated on the surface according to the following criteria in three stages, and the panel evaluation values were averaged to evaluate the tactile sensation of the water-absorbing sheet.
Stage A: The surface feel is smooth (evaluation value: 5).
Stage B: Although the surface feel is smooth, a foreign body sensation is felt (evaluation value: 3).
Stage C: The surface feel is uneven (evaluation value: 1).

<Odor sensory test of water absorbent sheet structure>
50 mL of fresh urine was placed in a 100 mL Meyer flask, 0.25 g of urea and 1 g of pulp collected from used diapers were added, and the solution was allowed to stand for 24 hours to prepare fermented urine. Next, the test solution was prepared by mixing fresh urine and the above fermented urine at a ratio of 9: 1 (mass ratio) (the fresh urine is sterile, so sufficient odor is generated if the fermented urine is not mixed) do not do).
A sample formed by cutting the water-absorbing sheet structure into a 5 × 5 cm square was placed in a 250 mL glass bottle as a sample, and then 30 g of the test solution was added from the top of the sample. After adding the test solution, it was immediately sealed and stored at 40 ° C. for 24 hours. After storage, five panelists (A to E) were asked to determine the odor in the 250 mL glass bottle according to the following criteria in accordance with the “standard 6-level odor intensity display method” of the standard criteria, and evaluated with the average value. .

Example 1
Quartz diorite is crushed, passed through a 425 μm sieve using a JIS standard sieve, and what remains on the 300 μm sieve is quartz diorite powder (mass average particle size: 363 μm; “quartz” It was used as “Diorenite powder A”.

84 parts by mass of an ethylene-vinyl acetate copolymer (EVA; melting temperature 95 ° C.) as an adhesive and a water-absorbing resin at the inlet of a roller-type spreader (manufactured by HASHIMA CORPORATION: Sinter Ace M / C) Cross-linked product of partially neutralized polymer of acrylic acid (manufactured by Sumitomo Seika Co., Ltd .: Aquakeep SA55SX-II, physiological saline water absorption rate: 42 seconds, mass average particle size: 360 μm; referred to as “water absorbent resin A”) A mixture of 270 parts by mass and 60 parts by mass of quartz diorite powder A was charged. On the other hand, a spunlace nonwoven fabric having a width of 30 cm (weight per unit area: 50 g / m ² , fiber: rayon / polyethylene terephthalate = 70/30; “spunlace nonwoven fabric”) was laid on the conveyor at the bottom of the roller-type spreader. . Subsequently, the mixture was uniformly laminated on the nonwoven fabric at a basis weight of 414 g / m ² by operating a spraying roller and a lower conveyor.

  The obtained laminate is sandwiched from above with a spunlace nonwoven fabric as a nonwoven fabric, and then heat-sealed with a laminating machine (manufactured by HASHIMA CORPORATION: linear adhesive press HP-600LF) whose heating temperature is set to 130 ° C. These were integrated and the water absorbing sheet structure was obtained. If the cross section of the structure of the obtained water-absorbing sheet composition is schematically shown, the structure is as shown in FIG.

  The obtained water-absorbent sheet structure was cut into a predetermined size and subjected to the various measurements and evaluations. The results are shown in Tables 3 and 4.

(Example 2)
A spunlace nonwoven fabric having a width of 30 cm as a nonwoven fabric was laid on a hot melt coating machine (Harrys Co., Ltd .: Marshall 150) set at a heating temperature of 150 ° C., and then a styrene-butadiene-styrene copolymer ( SBS (softening point 85 ° C.) was applied onto the nonwoven fabric at a basis weight of 25 g / m ² .

Next, a mixture of 270 parts by mass of water-absorbing resin A270 and 27 parts by mass of quartz diorite powder was charged into the inlet of a roller-type spreader (manufactured by Hashima Corporation: Sinter Ace M / C). On the other hand, the adhesive-coated nonwoven fabric was laid on the conveyor below the spreader so that the adhesive-coated surface was the upper surface. Subsequently, the mixture was uniformly laminated on the nonwoven fabric at a weight per unit area of 297 g / m ² by operating the spreading roller and the lower conveyor.

Laminating machine in which the obtained laminate was sandwiched between spunlace nonwoven fabrics coated with SBS as an adhesive in the same manner as described above with a basis weight of 25 g / m ² from the top, and the heating temperature was set to 100 ° C. These were integrated by heat-sealing with (manufactured by HASHIMA CORPORATION: linear adhesive press HP-600LF) to obtain a water absorbent sheet structure. If the cross section of the structure of the obtained water-absorbing sheet composition is schematically shown, the structure is as shown in FIG.

  The obtained water-absorbent sheet structure was cut into a predetermined size and subjected to the various measurements and evaluations. The results are shown in Tables 3 and 4.

(Example 3)
A spunlace nonwoven fabric having a width of 30 cm as a nonwoven fabric was laid on a hot melt coating machine (Harrys Co., Ltd .: Marshall 150) set at a heating temperature of 150 ° C., and then a styrene-butadiene-styrene copolymer ( SBS (softening point 85 ° C.) was applied onto the nonwoven fabric with a basis weight of 21 g / m ² .

Next, a mixture of 270 parts by mass of water-absorbing resin A and 9 parts by mass of quartz diorite powder was charged into the inlet of a roller-type spreader (manufactured by Hashima Corporation: Sinter Ace M / C). On the other hand, the adhesive-coated nonwoven fabric was laid on the conveyor below the spreader so that the adhesive-coated surface was the upper surface. Subsequently, the mixture was uniformly laminated on the nonwoven fabric at a weight per unit area of 279 g / m ² by operating the spray roller and the lower conveyor.

A laminate machine in which the obtained laminate was sandwiched between spunlace nonwoven fabrics coated with SBS as an adhesive in the same manner as described above at a basis weight of 21 g / m ² from the top, and the heating temperature was set to 100 ° C. These were integrated by heat-sealing with (manufactured by HASHIMA CORPORATION: linear adhesive press HP-600LF) to obtain a water absorbent sheet structure.

  The obtained water-absorbent sheet structure was cut into a predetermined size and subjected to the various measurements and evaluations. The results are shown in Tables 3 and 4.

Example 4
A spunlace nonwoven fabric having a width of 30 cm as a nonwoven fabric was laid on a hot melt coating machine (Harrys Co., Ltd .: Marshall 150) set at a heating temperature of 150 ° C., and then a styrene-butadiene-styrene copolymer ( SBS (softening point 85 ° C.) was applied onto the nonwoven fabric at a basis weight of 40 g / m ² .

Next, a mixture of 270 parts by mass of the water-absorbent resin A and 100 parts by mass of quartz diorite powder was charged into the inlet of a roller type spreader (manufactured by Hashima Co., Ltd .: Sinter Ace M / C). On the other hand, the adhesive-coated nonwoven fabric was laid on the conveyor below the spreader so that the adhesive-coated surface was the upper surface. Subsequently, the mixture was uniformly laminated on the nonwoven fabric at a weight per unit area of 370 g / m ² by operating the spreading roller and the lower conveyor.

Laminating machine in which the obtained laminate was sandwiched between spunlace nonwoven fabrics coated with SBS as an adhesive in the same manner as described above at a basis weight of 40 g / m ² from the top, and the heating temperature was set to 100 ° C. These were integrated by heat-sealing with (manufactured by HASHIMA CORPORATION: linear adhesive press HP-600LF) to obtain a water absorbent sheet structure.

  The obtained water-absorbent sheet structure was cut into a predetermined size and subjected to the various measurements and evaluations. The results are shown in Tables 3 and 4.

(Example 5)
In Example 2, quartz diorite was pulverized as a powder of quartz diorite to be used and passed through a sieve having an opening of 150 μm using a JIS standard sieve (mass average particle diameter: 75 μm; A water-absorbent sheet structure was obtained in the same manner as in Example 2 except that “rock powder B” was used.

  The obtained water-absorbent sheet structure was cut into a predetermined size and subjected to the various measurements and evaluations. The results are shown in Tables 3 and 4.

(Example 6)
In Example 2, quartz diorite was pulverized as a powder of quartz diorite used, passed through a sieve having an opening of 850 μm using a JIS standard sieve, and remained on the sieve having an opening of 600 μm ( A water-absorbent sheet structure was obtained in the same manner as in Example 2 except that mass average particle diameter: 725 μm; “Quartz diorite powder C” was used.

  The obtained water-absorbent sheet structure was cut into a predetermined size and subjected to the various measurements and evaluations. The results are shown in Tables 3 and 4.

(Example 7)
A spunlace nonwoven fabric having a width of 30 cm as a nonwoven fabric was laid on a hot melt coating machine (Harrys Co., Ltd .: Marshall 150) set at a heating temperature of 150 ° C., and then a styrene-butadiene-styrene copolymer ( SBS (softening point 85 ° C.) was applied onto the nonwoven fabric at a basis weight of 25 g / m ² .

Next, a mixture of 270 parts by mass of water-absorbing resin A270 and 27 parts by mass of quartz diorite powder was charged into the inlet of a roller-type spreader (manufactured by Hashima Corporation: Sinter Ace M / C). On the other hand, the adhesive-coated nonwoven fabric was laid on the conveyor below the spreader so that the adhesive-coated surface was the upper surface. Subsequently, the mixture was uniformly laminated on the nonwoven fabric at a weight per unit area of 297 g / m ² by operating the spreading roller and the lower conveyor.

An air-through nonwoven fabric (weight per unit area: 23 g / m ² , fiber: as a breathable fraction layer obtained by applying the SBS as an adhesive in the same manner as described above with a basis weight of 25 g / m ² from the top of the obtained laminate. After being sandwiched by polypropylene / polyethylene = 50/50; “air-through non-woven fabric”), heat-sealing with a laminating machine (manufactured by HASHIMA Co., Ltd .: linear adhesive press HP-600LF) set at a heating temperature of 100 ° C. These were integrated to obtain a water absorbent sheet constituting intermediate.

In the same manner as described above, the SBS was applied as an adhesive onto a water-absorbent sheet-constituting intermediate on a hot melt coater set at a heating temperature of 150 ° C. with a basis weight of 9 g / m ² .

Next, a cross-linked product of a partially neutralized acrylic acid polymer as a water-absorbing resin (Sumitomo Seika Co., Ltd .: Aquakeep 10SH-PB, physiological saline water absorption rate: 3 seconds, (Mass average particle size: 320 μm; “water-absorbing resin B”) 70 parts by weight and quartz diorite powder A17 parts by weight were mixed uniformly. On the other hand, a water absorbent sheet constituting intermediate was laid on the conveyor at the lower part of the spreader so that the adhesive application surface was the upper surface. Next, the mixture roller was uniformly laminated on the water absorbent sheet constituting intermediate with a weight per unit area of 87 g / m ² by operating the spreading roller and the lower conveyor.

The obtained laminate was sandwiched between spunlace nonwoven fabrics coated with the SBS in the same manner as described above with a basis weight of 9 g / m ² from the top, and then the laminating machine (Hashima Co., Ltd.) was set at a heating temperature of 100 ° C. (Manufactured by: linear adhesive press HP-600LF), these were integrated by heat fusion to obtain a water absorbent sheet structure. If the cross section of the structure of the obtained water-absorbing sheet composition is schematically shown, the structure is as shown in FIG.

The obtained water-absorbent sheet structure was cut into a predetermined size, and the various measurements and evaluations were performed so that the absorbent layer containing the water-absorbent resin A was on the upper side. The results are shown in Tables 3 and 4.

(Example 8)
A spunlace nonwoven fabric having a width of 30 cm as a nonwoven fabric was laid on a hot melt coating machine (Harrys Co., Ltd .: Marshall 150) set at a heating temperature of 150 ° C., and then a styrene-butadiene-styrene copolymer ( SBS (softening point 85 ° C.) was applied onto the nonwoven fabric at a basis weight of 20 g / m ² .

Next, the water-absorbent resin A was charged into the inlet of a roller-type spreader (manufactured by Hashima Corporation: Sinter Ace M / C). On the other hand, the adhesive-coated nonwoven fabric was laid on the conveyor below the spreader so that the adhesive-coated surface was the upper surface. Subsequently, the water-absorbing resin A was uniformly laminated on the nonwoven fabric with a basis weight of 270 g / m ² by operating the spreading roller and the lower conveyor.

The obtained laminate was sandwiched with an air-through nonwoven fabric as a breathable fraction layer in which the SBS as an adhesive was applied from the top at a basis weight of 20 g / m ² in the same manner as described above, and then the heating temperature was 100 ° C. These were integrated by heat-sealing with a laminating machine (manufactured by HASHIMA CORPORATION: linear adhesive press HP-600LF) to obtain a water-absorbing sheet constituting intermediate.

In the same manner as described above, the SBS was applied as an adhesive onto a water-absorbent sheet-constituting intermediate on a hot melt coater set at a heating temperature of 150 ° C. with a basis weight of 9 g / m ² .

Next, a mixture of 70 parts by mass of water-absorbing resin B and 17 parts by mass of quartz diorite powder A was charged into the charging port of the roller type spreader. On the other hand, a water absorbent sheet constituting intermediate was laid on the conveyor at the lower part of the spreader so that the adhesive application surface was the upper surface. Next, the mixture roller was uniformly laminated on the water absorbent sheet constituting intermediate with a weight per unit area of 87 g / m ² by operating the spreading roller and the lower conveyor.

The obtained laminate was sandwiched between spunlace nonwoven fabrics coated with the SBS in the same manner as described above with a basis weight of 9 g / m ² from the top, and then the laminating machine (Hashima Co., Ltd.) was set at a heating temperature of 100 ° C. (Manufactured by: linear adhesive press HP-600LF), these were integrated by heat fusion to obtain a water absorbent sheet structure. If the cross section of the structure of the obtained water-absorbing sheet composition is schematically shown, the structure is as shown in FIG.

The obtained water absorbent sheet structure was cut into a predetermined size, and the various measurements and evaluations were performed so that the water absorbent layer containing the water absorbent resin A was on the upper side. The results are shown in Tables 3 and 4.

(Comparative Example 1)
In Example 2, the quartz diorite powder was not used, and the adhesive applied to the non-woven fabric was used in a basis weight of 20 g / m ² (adhesive content: 40 g / m ² ). A water-absorbent sheet structure was obtained by the same method. The obtained water-absorbent sheet structure was cut into a predetermined size and subjected to the various measurements and evaluations. The results are shown in Tables 3 and 4.

(Comparative Example 2)
In Example 8, the weight of the adhesive applied to the nonwoven fabric on the absorbent layer side containing the water-absorbent resin B without using the quartz diorite powder was 6 g / m ² (adhesive content: 12 g / m). ^A water absorbent sheet structure was obtained in the same manner as in Example 8 except that it was used in ² ). The obtained water-absorbent sheet structure was cut into a predetermined size, and the various measurements and evaluations were performed so that the absorbent layer containing the water-absorbent resin A was on the upper side. The results are shown in Tables 3 and 4.

Table 2 shows the configuration of the water-absorbing sheet structure in Examples and Comparative Examples, Table 3 shows the performance of the water-absorbing sheet structure, and Table 4 shows the results of the odor sensory test of the water-absorbing sheet structure.

＊：吸水性樹脂の含有量（質量基準）に対する割合。
＊＊：吸水性樹脂及び石英閃緑玲岩の粉末の合計含有量（質量基準）に対する割合。

*: Ratio to the content (mass basis) of the water absorbent resin.
**: Ratio to the total content (mass basis) of water-absorbent resin and quartz diorite rock powder.

  From Tables 2-4, the water absorption sheet structure of Examples 1-8 contains the liquid of a liquid permeation rate, a liquid reversal amount, and an odor with respect to Comparative Examples 1 and 2 by containing the powder of quartz diorite in the absorption layer. It was found to have excellent performance in the sensory test.

  When the content of quartz diorite is low (Example 3) or when the mass average particle size of quartz diorite is small (Example 5), liquid penetration rate, liquid reversal amount and odor sensory test There was little effect. On the other hand, when the content of the quartz diorite powder is large (Example 4), although the liquid penetration rate, the liquid reversion amount, and the odor sensory test are excellent, the leak amount and the tactile sensation on the slope deteriorated. Moreover, when the mass average particle diameter of the quartz diorite powder was large (Example 6), the tactile sensation was particularly poor.

  The water-absorbent sheet structure according to the present invention can be used for absorbent articles in the sanitary material field, building material field, and the like, and in particular, can be suitably used for absorbent articles in the sanitary material field.

DESCRIPTION OF SYMBOLS 10 Water-absorbing sheet structure 11 Adhesive 12 Water-absorbing resin 13 Quartz diorite powder 14 Absorbing layer 15 Non-woven fabric 16 Non-woven fabric 17 Adhesive 18 Water-absorbing resin 19 Breathable fractionation layer 20 Primary absorbent layer 21 Secondary absorbent layer 31 Base 32 Acrylic plate 33 Absorbent article 34 Drip funnel 35 Balance 36 Tray

Claims (4)

An absorbent layer comprising a water-absorbent resin and an adhesive is a water-absorbent sheet structure having a structure sandwiched from above and below the absorbent layer by a nonwoven fabric, wherein the absorbent layer is a quartz diorite powder A water-absorbent sheet structure further comprising: The water absorption sheet | seat structure of Claim 1 whose content rate of the powder of quartz diorite in an absorption layer is the range of 0.04-0.35 times with respect to content (mass basis) of a water absorbing resin. body. The water-absorbent sheet structure according to claim 1 or 2, wherein the quartz diorite powder has a mass average particle diameter of 100 to 600 µm.   An absorptive article formed by sandwiching the water-absorbent sheet structure according to any one of claims 1 to 3 between a liquid-permeable sheet and a liquid-impermeable sheet.

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