Abstract:
(EN) The purpose of the present invention is to provide a water absorbent article that has high water absorbency and high flexibility and, when used as a cleaning sheet, shows excellent ability to collect waste and dust even on a wet floor, etc. The method according to the present invention for manufacturing a water absorbent article ( 1 ) is characterized by comprising: a fiber lamination step for laminating a flexibility-imparting layer ( 6 ) having water absorbency on a liquid-permeable surface sheet layer ( 5 ) to form a sheet body ( 35 ); an emboss processing step for embossing the sheet body ( 35 ), said sheet body ( 35 ) being in a non-wet state, to form a bulky part provided with a number of peaks and valleys in the sheet body ( 35 ); and a binder impregnation step for, after the emboss processing step, supplying a binder to the sheet body ( 35 ) from an external surface side and thus impregnating the sheet body ( 35 ) with the binder.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a method of manufacturing a water absorbent article that can be used for cleaning articles and a water absorbent article manufactured thereby. 
       BACKGROUND ART 
       [0002]    A water absorbent article that can be used for cleaning articles includes multi-layered sheets of tissue paper adhered to one another through a water-soluble binder and embossed to form high bulky structure in the form of a plurality of protrusions and depressions. The embossed multi-layered sheets are then impregnated with an aqueous chemical. A cleaning article having such basic structure is disclosed in, for example, Patent Literature 1 below. 
       CITATION LIST 
     Patent Literature 
       [0003]    Patent Literature 1: JP-U No. 2-103397 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0004]    Regarding the cleaning articles described in Patent Literature 1, a plurality of sheets of water-soluble paper are layered on the top of one another, between each two of which a water-soluble adhesive bonds. Projections and depressions are embossed into the sheets of water-soluble paper on the whole to form a towel element which is then impregnated with a sterilizing solution. However, the process of bonding between paper sheets by means of an adhesive requires time and manpower, increasing manufacturing cost. 
         [0005]    Another way for manufacturing cleaning articles is through processes of layering a plurality of base paper sheets and then spraying a binder onto the base paper sheets, then embossing the base paper sheets and then impregnating them with aqueous chemicals. However, if the base paper sheets containing the binder are embossed, the base paper sheet adheres to an emboss roller, giving rise to the disadvantage that the embossed base paper sheet does not easily come off the roller. 
         [0006]    To prevent the base paper sheet from adhering to the emboss roller, it is required to apply a releasing agent to the emboss roller or to apply a releasing agent to the base paper sheet, involving time, effort and difficulties. 
         [0007]    The present invention has been made in view of the foregoing, and an object of the present invention is to provide a method for manufacturing a water absorbent article at low cost manufacture and in simple manufacturing processes without the disadvantage of adhesion to an emboss apparatus with a binder during an emboss process. 
       Solution to Problem 
       [0008]    The present invention is: 
         [0009]    (1) A method for manufacturing an water absorbent article, including the steps of: an accumulating fiber process of accumulating a softness imparting layer having absorbency on a surface sheet layer having liquid permeability to form a sheet body; an embossing process of performing embossing on the sheet body that is in a non-wet state to form a bulk portion formed from a plurality of uneven bodies in the sheet body; and a binder impregnating process of applying a binder to the sheet body from outside after the embossing process and impregnating the binder into the sheet body. 
         [0010]    (2) The method for manufacturing a water absorbent article according to (1), wherein the softness imparting layer is constituted by an aggregate of fibers, wherein the fibers exist densely in a compressed state in a region of a boundary face between the surface sheet layer and the softness imparting layer. 
         [0011]    (3) The method for manufacturing a water absorbent article according to (1) or (2), wherein the softness imparting layer is formed from a crushed pulp of a material including crushed pulp. 
         [0012]    (4) The method for manufacturing a water absorbent article according to (3), wherein a blending ratio of the crushed pulp in the softness imparting layer is 80% or more. 
         [0013]    (5) The method for manufacturing a water absorbent article according to any one of (1) to (4), wherein the surface sheet layer is formed from a first surface sheet layer and a second surface sheet layer, wherein the softness imparting layer is formed between the first surface sheet layer and the second surface sheet layer. 
         [0014]    (6) The method for manufacturing a water absorbent article according to any one of (1) to (5), wherein the binder is impregnated into the softness imparting layer in a region near joining face where the surface sheet layer and the softness imparting layer are joined. 
         [0015]    (7) The method for manufacturing a water absorbent article according to any one of (1) to (6), wherein the binder is a cross-linked binder. 
         [0016]    (8) The method for manufacturing a water absorbent article according to any one of (1) to (7), wherein the softness imparting layer has a bulk forming function. 
         [0017]    (9) An absorbent article manufactured by the manufacturing method according to any one of (1) to (8). 
       Advantageous Effects of Invention 
       [0018]    According the present invention, a method for manufacturing a water absorbent article at low cost manufacture and in simple manufacturing processes without the disadvantage of adhesion to an emboss apparatus with a binder during an emboss process and a water absorbent article manufactured by the method can be provided. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0019]      FIG. 1  is a plan view illustrating a configuration of a first embodiment of a water absorbent article according to the present invention. 
           [0020]      FIG. 2  is an enlarged perspective view of the water absorbent article according to the first embodiment. 
           [0021]      FIG. 3  is a cross-sectional view taken along line A-A of  FIG. 1 . 
           [0022]      FIG. 4  is a view to explain an example of a manufacturing process of the absorbent article. 
           [0023]      FIG. 5  is a plan view illustrating a configuration of a second embodiment of the water absorbent article according to the present invention. 
           [0024]      FIG. 6  is a cross-sectional view taken along line B-B of  FIG. 5 . 
           [0025]      FIG. 7  is a cross-sectional view illustrating a configuration of a third embodiment of the water absorbent article according to the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0026]    A first embodiment of a water absorbent article  1  according to the present invention will be described with reference to  FIGS. 1 to 3 .  FIG. 1  is a plan view of a water absorbent article  1  according to the present invention,  FIG. 2  is an enlarged perspective view of the water absorbent article, and  FIG. 3  is a cross-sectional view taken along line A-A of  FIG. 1 . 
         [0027]    As shown in  FIGS. 1 and 2 , the water absorbent article  1  according to the present embodiment is configured as a sheet body of which a surface thereof is subjected to embossing and in which embosses  4  including a plurality of protrusions  2  and depressions  3  are formed. Note that shapes of the protrusions  2  and the depressions  3  of the emboss  4  can be determined as desired. For example, the shape of the emboss  4  may be circular, elliptical, triangular, rectangular, or rhombic; or a different shape such as, for example, a pattern/design or a corrugated shape in which the protrusions  2  and the depressions  3  having a linear shape are repeatedly formed. Moreover, these protrusions  2  and depressions  3  may be formed throughout an entire surface of the water absorbent article  1 , or may be formed only in a portion of the water absorbent article  1 . In the present embodiment, the case in which the water absorbent article  1  has the embosses  4  is described, but the embosses  4  may not necessarily be formed. 
         [0028]    Moreover, the water absorbent article  1  of the present application may be water-disintegrable or non-water-disintegrable. 
         [0029]    As shown in  FIG. 3 , the water absorbent article  1  of the present invention is formed from a surface sheet layer  5  having liquid permeability and a softness imparting layer  6  having absorbency. The surface sheet layer  5  is formed from a first surface sheet layer  7  and a second surface sheet layer  8 , and the water absorbent article  1  is constituted by an accumulated-fiber body  1   a  in which the softness imparting layer  6  is accumulated between the first surface sheet layer  7  and the second surface sheet layer  8 . Note that hereinafter, when the first surface sheet layer  7  and the second surface sheet layer  8  are described without distinction, the first surface sheet layer  7  and the second surface sheet layer  8  are referred to collectively as the surface sheet layer  5 . 
         [0030]    The surface sheet layer  5  and the softness imparting layer  6  are bonded through a binder that is impregnated into at least one layer of the surface sheet layer  5  and the softness imparting layer  6 . In order to bond the surface sheet layer  5  and the softness imparting layer  6 , the binder need to he impregnated into at least one layer of the boundary between the surface sheet layer  5  and the softness imparting layer  6 . The “boundary between the surface sheet layer  5  and the softness imparting layer  6 ” includes a mode of between the first surface sheet layer  7  and the softness imparting layer  6 , a mode of between the second surface sheet layer  8  and the softness imparting layer  6 , a mode of between the first surface sheet layer  7  and the softness imparting layer  6 , and a mode of between the second surface sheet layer  8  and the softness imparting layer  6 . Particularly, the water absorbent article  1  is configured such that the binder is impregnated into the softness imparting layer  6  in any of a region near the boundary face  9   a  between the first surface sheet layer  7  and the softness imparting layer  6 , a region near the boundary face  9   b  between the second surface sheet layer  8  and the softness imparting layer  6 , or a region near the boundary face  9   a  and boundary face  9   b,  thus increasing the joining strength. Furthermore, preferably the binder is impregnated into both of the surface sheet layer  5  and the softness imparting layer  6  in the region, further increasing the joining strength between the surface sheet layer  5  and the softness imparting layer  6 . Note that the boundary face  9   a  can be referred to as a joining face where the first surface sheet layer  7  and the softness imparting layer  6  are joined, and the boundary face  9   b  can be referred to as a joining face where the second surface sheet layer  8  and the softness imparting layer  6  are joined. 
       Surface Sheet Layer 
       [0031]    The surface sheet layer  5  is formed by a material having liquid permeability, but it is preferably formed using a paper material produced by a base paper sheet which is formed from pulp paper or a material including pulp as a principal raw material and subjected to various processing. For the paper material used for the surface sheet layer  5 , the pulp preferably constitutes 30% or more. When the surface sheet layer  5  is formed from a paper material in which the pulp constitutes 30% or more, the softness of the water absorbent article  1  as a whole can be increased and production efficiency during manufacturing can be improved. Moreover, by increasing the proportion of the pulp, it is possible to facilitate the decomposition of the water absorbent article  1  after disposal in, for example, soil. Therefore, the environment burden can be further reduced and concern for the environment can be raised. For the paper material for forming the surface sheet layer  5 , more preferably the pulp constitutes 50% or more, and furthermore preferably 80% or more. Note that when a plurality of surface sheet layers  5  are formed, the thickness and materials of the surface sheet layers  5  may be the same, or may be different. 
         [0032]    Examples of raw material pulp include, for example, wood pulp, synthetic pulp, and waste paper pulp. The present invention can use toilet paper material as the raw material pulp. As the toilet paper material, for example, the raw material pulp constituted by blending, at predetermined proportions, softwood bleached kraft pulp obtained from softwood such as red pine, Yezo spruce, Sakhalin fir, Douglas fir, hemlock, and spruce; and hardwood bleached kraft pulp obtained from hardwood such as beech, oak, birch, eucalyptus, oak, poplar, and alder can be used. In present invention, the surface sheet layer  5  is not limited to natural fiber such as pulp, and regenerated fiber such as rayon can be also used. Although the blend of natural fiber and regenerated fiber can be used, natural fiber is preferably used. As natural fibers other than pulp, for example, kenaf, bamboo fibers, straw, cotton, cocoon filament, sugarcane and the like can be used. Note that, the paper material used in the surface sheet layer  5  may be water-disintegrable or may not he water-disintegrable. Moreover, the paper material used in the surface sheet layer  5  is not limited to the examples described above. 
       Softness Imparting Layer 
       [0033]    The softness imparting layer  6  is constituted by an aggregate of a plurality of fibers and has absorbency. The softness imparting layer  6  is formed from natural fiber such as pulp, regenerated fiber such as rayon, or a blend of natural fiber and regenerated fiber. As the natural fiber other than pulp, for example, kenaf, bamboo fibers, straw, cocoon, cocoon filament, sugarcane, and the like can he used. The softness imparting layer  6  is preferably formed such that a degree of density of the fibers in a thickness direction varies, and particularly it is preferably formed such that the fibers exist densely in a compressed state in a region of boundary face  9   a  between the first surface sheet layer  7  as the surface sheet layer  5  and the softness imparting, layer  6 , increasing the strength of the water absorbent article. 
         [0034]    More preferably the softness imparting layer  6  is formed from the crushed pulp  11  or a material including the crushed pulp  11 . The material used in the softness imparting layer  6  with the crushed pulp  11  includes pulp other than the crushed pulp, natural fiber other than pulp, and regenerated fiber such as rayon. Here, the term “crushed pulp  11 ” refers to a cotton-like material obtained by finely crushing the pulp material such as paper material that becomes the raw material, using a crusher. The raw material pulp of the crushed pulp  11  can include wood pulp, synthetic pulp, and waste paper pulp, as in the surface sheet layer  5 , and the toilet paper material can be also used. As the toilet paper material, a blend of the softwood bleached kraft pulp and the hardwood bleached kraft pulp as in the surface sheet layer  5  can be used. However, from the perspective of manufacturing, a raw material pulp constituted from the softwood bleached kraft pulp is preferably used. Because the softwood bleached kraft pulp has longer fiber length than the hardwood bleached kraft pulp, when the softness imparting layer  6  is constituted using the crushed pulp  11  obtained from the softwood bleached kraft pulp, the degree of entangling of the fibers is increased, as a result, the strength is enhanced. Moreover, the volume of space between the fibers due to entanglement of the fibers is greater than that in the case where the hardwood bleached kraft pulp having shorter fiber length is used, and a degree of freedom for each of the fiber to move is increased, and thus the softness is improved. Note that the material of the pulp material used for forming the softness imparting layer  6  may be different from or the same as the material forming the surface sheet layer  5 . 
         [0035]    When the material used for the softness imparting layer  6  is formed from the crushed pulp  11  or the material including the crushed pulp  11  as a principal raw material, a blending proportion of the crushed pulp  11  in the material is preferably 30% or more, and more preferably 50% or more. Furthermore, even more preferably, the blending proportion of the crushed pulp  11  in the material is 80% or more. It is more preferable that the softness imparting layer  6  is formed from the crushed pulp by 100%. As the crushed pulp is formed to be cotton-like with the pulp material crushed, a larger number of spaces are formed between fibers than paper that is made through paper-making in which fibers are in a compressed state. When a large number of spaces are formed between fibers, a degree of freedom for each of the fibers constituting the softness imparting layer  6  to move can be increased. Therefore, when the crushed pulp  11  is blended at the above-mentioned proportion, a bulk forming function in the softness imparting layer  6  can be enhanced even at a lower basis weight, and the higher proportion of the crushed pulp  11  can enhance the bulk forming function even if the basis weight of the softness imparting layer  6  is reduced. Moreover, the lame number of spaces which are formed between the fibers constituting the softness imparting layer  6  retain the higher water content, thus improving absorbency. As a result, the softness as a whole can be increased, and production efficiency during manufacturing can be improved. Note that the term “bulk forming function” is a function of increasing the bulk of the accumulated-fiber body  1   a  in which the surface sheet layer  5  and the softness imparting layer  6  are accumulated. 
         [0036]    Note that the basis weight of the softness imparting layer  6  is preferably 80 g/m 2  or less, and more preferably 60 g/m 2  or less. By setting the basis weight of the softness imparting layer  6  to the range described above, manufacturing and packaging of the water absorbent article  1  can be facilitated, and the water absorbent article  1  can be formed having bulk that facilitates use by a user and packaging. Moreover, by setting the basis weight of the softness imparting layer to the range described above, there will be no too larger fiber density. As a result, an amount of the hinder for joining between the fibers can be reduced. Therefore, a large amount of binder adhering to the surface of the surface sheet layer  5  and forming a film, and then decreasing the liquid permeability of the surface sheet layer  5  can be prevented, and absorbency of the water absorbent article  1  as a whole can be ensured. 
       Binder 
       [0037]    Any of various types of binders can be used, provided that the binder has a predetermined adhesive strength and can impart a predetermined strength to the surface sheet layer  5  and the softness imparting layer  6 . Examples of the binder that can be used in the present invention include polysaccharide derivatives, natural polysaccharides, and synthetic polymers. Examples of the polysaccharide derivatives include carboxymethyl cellulose, carboxyethyl cellulose, carboxymethy starch or a salt thereof, starch, methyl cellulose, and ethyl cellulose. Examples of the natural polysaccharides include guar gum tragacanth gum, xanthan gum, sodium alginate, carrageenan, gum arabic, gelatin, and casein. Moreover, examples of the synthetic polymer include polyvinyl alcohol, ethylene-vinyl acetate copolymer resin, polyvinyl alcohol derivative, polymers or copolymers of unsaturated carboxylic acid, or a salt thereof; and examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic anhydride, maleic acid, and fumaric acid. Of these, carboxymethyl cellulose and polyvinyl alcohol are particularly preferable. 
         [0038]    When the binder is a cross-linked binder, it is preferable that the physical strength of the water absorbent article  1  is increased. The crosslinking agent for crosslinking the hinder causes a crosslinking reaction with the binder  37  and forms the binder  37  into crosslinking structure. As a result, physical strength is increased. 
         [0039]    When the binder having carboxyl group such as carboxymethyl cellulose is used, a polyvalent metal ion is preferably used as the crosslinking agent, and examples of the polyvalent metal ion include zinc, alkaline earth metals such as calcium and barium, and metal ions such as magnesium, aluminum, manganese, iron, cobalt, nickel, and copper. Specifically, ions of zinc, calcium, barium, magnesium, aluminum, iron, cobalt, nickel, and copper are advantageously used, which are preferable from the perspective of imparting a sufficient wet strength. The polyvalent metal ion as the crosslinking agent is used in the form of a water-soluble metal salt such as sulfate, chlorides, hydroxides, carbonates, and nitrates. 
         [0040]    Moreover, when the polyvinyl alcohol is used as the binder, a titanium compound, a boron compound, a zirconium compound, a compound containing silicon, or the like can be used as the crosslinking agent, and one or a mixture of a plurality of these compounds can be also used as the crosslinking agent. Examples of the titanium compound include titanium lactate and titanium triethanol aminate; and examples of the boron compound include borax and boric acid. Moreover, examples of the zirconium compound include zirconium ammonium carbonate, and examples of the compound containing silicon include sodium silicate. 
         [0041]    In the example described above, the case has been described where the water absorbent article is configured such that the surface sheet layers are on both surfaces of the softness imparting layer, but the water absorbent article may be configured such that the surface sheet layer is provided only on one surface of the softness imparting layer. Further, the surface sheet layers may be provided on both surfaces of the softness imparting layer, and a softness imparting layer may be further accumulated on one surface or both surfaces of the surface sheet layer. Furthermore, the surface sheet layer may be further provided on at least one surface of the softness imparting layer, and the number of the softness imparting layers and the surface sheet layers may be optionally adjusted. 
       Manufacturing Method 
       [0042]    Next, an example of a method for manufacturing the water absorbent article  1  according to the present invention will be described with reference to  FIG. 4 . Note that in the manufacturing method, “upstream side” refers to a side where the base paper sheet (described below) is supplied at a predetermined point in the manufacturing process, and “downstream” refers to a side where the supplied base paper sheet is discharged at a predetermined point in the manufacturing process. 
         [0043]    In  FIG. 4 , reference sign  21  is a first feeding roll on which a first base paper sheet  24  for forming the first surface sheet layer  7  is wound, reference sign  22  is a second feeding roll on which a second base paper sheet  25  for forming the second surface sheet layer  8  is wound, and reference sign  23  is a third feed roll on which a pulp sheet  26  of crushed pulp raw material for forming the softness imparting layer  6  is wound. Moreover, the first base paper sheet  24 , the second base paper sheet  25  and the pulp sheet  26  may employ a single layer structured sheet constituted by one layer of thin paper such as toilet paper or a multilayer structured sheet constituted by a plurality of layers of thin paper. 
       Crushed Pulp Accumulating Process 
       [0044]    The first base paper sheet  24  is fed by a first pinch roller  27  in a direction of the X arrow so as to be fed into a crusher  31 . Additionally, the pulp sheet  26  is fed by a third pinch roller  29  in a direction of the Y arrow so as to be fed into the crusher  31 . 
         [0045]    The crusher  31  is provided with a crushing part  33  inside a housing  32 , and an airflow forming mechanism F that draws an air in the housing  32  and forms an airflow The pulp sheet  26  is crushed by the crushing part  33  upon being fed into the crusher  31 . 
         [0046]    Then, in the housing  32 , the crushed pulp (crushed pulp  11 ) moves in a surface direction of the first base paper sheet  24  (in a direction B in the drawing) while the fibers are detangled or entanglement between the fibers is relaxed by the airflow formed by the airflow forming mechanism F, and is drawn and accumulated on the first base paper sheet  24  while being sequentially compressed. 
         [0047]    Therefore, it is said that the fibers of the crushed pulp  11  exist densely in the most compressed state in the region of boundary face with the layer formed by the fibers of the crushed pulp  11  being accumulated on the surface of the first base paper sheet  24 . Since the crushed pulp  11  exists densely in a compressed state in the boundary region between the first base paper sheet  24  forming the first surface sheet layer  7  and the layer of the crushed pulp  11  for forming the softness imparting layer  6 , the fibers that exists densely and the fibers of the first base paper sheet  24  are densely joined by the binder  37 , thus increasing the bonding strength with the first surface sheet layer  7  in the resulting absorbent article  1 . 
         [0048]    On the other hand, a density of the crushed pulpit in the boundary region between the layer of the crushed pulp  11  and the second base paper sheet  25  is more sparsely than the density in the boundary region between the first base paper sheet  24  and the layer of the crushed pulp  11  for forming the softness imparting layer  6 , thereby weakening joining strength between the surface sheet layer  5  and the softness imparting layer  6  in the resulting absorbent article  1  and improving softness in the surface. Thus, the absorbent article  1  having both superior strength and softness can be obtained. 
         [0049]    In the present embodiment, because the crushed pulp  11  is accumulated on the first base paper sheet  24  by the airflow as described above, the softness imparting layer  6  has softness compared with paper made by a paper-making process including a press process. 
         [0050]    Moreover, for example, unlike a paper making process including a plurality of processes, the manufacturing method is simple because the crushed pulp has only to be crushed and accumulated. 
         [0051]    Further, when the layer is formed through a paper making process, the presence of the press process causes the fiber-fiber to be crushed, but in the present embodiment, the fibers of the crushed pulp are only accumulated, so that there is a space between the fibers. As a result, the layer of the present embodiment can be bulkier at the same basis weight than that manufactured by a paper-making, and air permeability can be improved. 
         [0052]    Furthermore, as the fiber-fiber is not crushed, the impregnation of the binder can be facilitated. As a result, the drying time in the manufacturing method can be shortened, and the manufacturing method can be efficient. 
         [0053]    As described above, the first base paper sheet  24  on which the crushed pulp  11  has been accumulated in the housing  32  of the crusher  31  is discharged out of the crusher  31  while moving in the X direction. 
       Second Base Paper Sheet Laminating Process 
       [0054]    Then, on a downstream side of the crusher  31 , the second base paper sheet  25  is laminated on the surface of the first base paper sheet  24  where the crushed pulp  11  is accumulated. The second base paper sheet  25  is fed in the Z direction by a second pinch roller  28 , and is laminated on the first base paper sheet  24 . At this point, the first base paper sheet  24 , the crushed pulp  11  and the second base paper sheet  25  are sequentially laminated and accumulated to form a sheet body  35 . 
       Embossing Process 
       [0055]    The sheet body  35  is passed through a pair of vertical emboss rollers  34 , and is subjected to the embossing here. The emboss rollers  34  can employ a plurality of embossing protrusions (uneven bodies) on a peripheral surface of the rollers as conventionally known. 
         [0056]    However, the emboss rollers  34  is not limited to this, and may be a combination of emboss rollers, in which the uneven bodies are projected, and flat rollers. 
         [0057]    The material of emboss roller  34  may be a steel material or an elasticity material (such as a rubber material). 
         [0058]    For example, uneven shaping by the embossing may be performed on only one side of the sheet body  35  from either one of the first base paper sheet  24  or the second base paper sheet  25 , or may be performed on both front and back sides of the sheet body  35 , that is, the first base paper sheet  24  side and the second base paper sheet  25  side. 
         [0059]    The sheet body  35  is in a non-wet state at this time, and the embossing is performed on the sheet body  35  that is in a non-wet state. 
         [0060]    Herein, the non-wet state does not include the mode in which moisture is applied to the sheet body  35  such as by blowing water on the sheet body  35 . Ordinary, paper materials include moisture (water content) corresponding to conditions of air temperature and humidity, but the moisture (water content) is not water content that is actively supplied from outside. As such, even if such moisture (water content) is included, this corresponds to the non-wet state according to the present invention. 
         [0061]    Accordingly, the percentage content of moisture (water content) included in the sheet body  35  varies depending the conditions of air temperature and humidity and regardless of the numeric value of the percentage content, it can be understood that this corresponds to the non-wet state according to the present invention. 
         [0062]    The embossing is performed on the base paper sheet that is in an ordinary dry and non-wet state under the atmosphere, and thus there is no possibility of the sheet body  35  adhering to the emboss rollers  34 , as there is in cases where the sheet body  35  is subjected to embossing in a wet state in which the sheet body  35  is impregnated with the binder. Therefore, there is no need to apply a releasing agent to the emboss rollers  34  or to apply a releasing agent to the sheet body  35 . 
         [0063]    The embossing is able to be performed without the emboss rollers  34  being heated, but the embossing may be performed with the emboss rollers  34  heated to a predetermined temperature. In the latter, a heating temperature for the emboss roller  34  preferably ranges from 60° C. to 150° C. 
         [0064]    When the embossing is performed, the embosses  4  including the plurality of protrusions  2  and depressions  3  are formed in the sheet body  35  as shown in  FIGS. 1 and 2 , and the plurality of embosses  4  forms a bulk portion  36 . At this time, the bulky feel can be increased because the crushed pulp  11  exists between the first base paper sheet  24  and the second base paper sheet  25 . As the crushed pulp  11  is cotton-like, when the softness imparting layer  6  is formed from the crushed pulp or a material including the crushed pulp, the softness imparting layer  6  can impart the bulky feel. 
         [0065]    Herein, in the present invention, the embossing is performed on the sheet body  35  that is in a non-wet state, and thus, compared with the case of a wet state, the ductility during the process may not be necessarily excellent. In such a case, the sheet body  35  may not respond the load force of the embossing depending on an emboss depth, so that breaking of part of bonds between fibers may occur. 
         [0066]    A small emboss depth is unlikely to cause such fiber-fiber bond breaking, but a large emboss depth is likely to cause the fiber-fiber bond breaking. For example, when the emboss depth ranges from 1 mm to 5 mm, the fiber-fiber bond breaking easily occurs. It is suggested that in present invention, the occurrence of fiber-fiber bond breaking is a desirable embodiment as described below, if anything. 
         [0067]    In the present embodiment, in the method for manufacturing a water absorbent article, the base paper sheet to which water content is not supplied is used, and the base paper sheet which does not include a water-soluble binder and is in a non-wet state is subjected to embossing, and thus there is no possibility of the base paper sheet adhering to the emboss apparatus. Accordingly, there is no need to apply a releasing agent to the emboss apparatus, simplifying the embossing process and improving manufacturing efficiency. As a result, according to the present invention, the absorbent article can be easily manufactured and a reduction in manufacturing cost is achieved. 
       Binder Impregnating Process 
       [0068]    In the next process, the binder  37  such as carboxymethyl cellulose is applied to the sheet body  35  in which the bulk portion  36  is formed by the plurality of uneven bodies  4 . 
         [0069]    The binder  37  is applied by spraying a solution of the binder  37  from a nozzle of a spraying device onto the front surface and the back surface of the sheet body  35 , Thus, the binder  37  is applied from the front and back (outer) sides of the sheet body  35  and impregnated into the sheet body  35 . 
         [0070]    In this case, in the present embodiment, the binder  37  is sprayed onto both the front and back surfaces of the sheet body  35  and impregnated into at least one of the surface sheet layer  5  and the softness imparting layer  6 , that is, more specifically, the binder is impregnated into the first surface sheet layer  7 , the second surface sheet layer  8  and the softness imparting layer  6 . However, provided that the binder  37  capable of bonding the surface sheet layer  5  and the softness imparting layer  6  is impregnated into at least either of the surface sheet layer  5  and the softness imparting layer  6 , the binder may be sprayed onto only the surface of one of the front and back sides of the sheet body  35 . 
         [0071]    A conventionally known spray nozzle may be selected as desired as the spray nozzle used for the spraying. 
         [0072]    The means for supplying the binder  37  is not limited to the above-described spraying. For example, a technique of dropping the binder  37  onto the surface of the sheet body  35 , and a technique of applying coating of the same, and the like may be adopted. 
         [0073]    Moreover, hinders other than carboxymethyl cellulose, polyvinyl alcohol, ethylene-vinyl acetate copolymer resin, and other substances may be used as the binder  37 . 
         [0074]    There are cases in which the binder  37  penetrates from one surface of the sheet body  35  to an opposing surface in the thickness direction and is impregnated throughout all layers in the thickness direction; and cases in which the binder  37  penetrates not to the opposing surface in the thickness direction, but only partway, that is, there are cases in which while the binder  37  is impregnated up to at least the boundary face between the first base paper sheet  24  the layer formed by the fibers of the crushed pulp  11  being accumulated thereon, and the boundary face between the second base paper sheet  25  and the layer formed by the fibers of the crushed pulp  11  being accumulated thereon, the binder  37  is not impregnated into the entirety of the sheet body  35 , but rather into only a portion thereof. 
         [0075]    This is the same for cases in which the solution of the binder  37  is applied from one side of the sheet body  35 , and cases in which the solution of the binder  37  is applied from both sides of the sheet body  35 . When a crosslinking agent of the binder is added as needed, the crosslinking agent can be applied simultaneously with the binder, but the present invention is not limited to this. The crosslinking agent may be applied and added at an arbitrary point in the manufacturing process. 
         [0076]    By a supply of the binder as described above, the binder is impregnated into the sheet body  35 . Here, the present embodiment includes the mode in which a part of fiber-fiber bond may break in the sheet body  35  in the embossing process. 
         [0077]    When such fiber-fiber bond breaking occurs in the sheet body  35 , a spot of the fiber-fiber bond breaking becomes a region that facilitates penetration of the binder, thereby increasing the speed of penetration of the binder as a whole. 
         [0078]    Accordingly, the speed of penetration of the binder is greater than that in the case when the fiber-fiber bond breaking does not occur, enabling penetration of the binder with efficiency. 
         [0079]    Moreover, when the binder flows into the spot of the fiber-fiber bond breaking, the fibers are bonded together through the binder, making the fiber-fiber bond tight. 
         [0080]    Specifically, after the binder dries to a film, the strength of the binder film is greater than the strength of the fiber, thus achieving an enhancement in the strength of the sheet body  35 . Furthermore, after cross-links are formed as described below, the strength of the binder film becomes further greater. 
       Drying Process 
       [0081]    The sheet body  35  impregnated with the binder  37  is transported to a dryer  38  and, here, subjected to drying. Hot-air drying, infrared drying, or a similar conventionally known method may be optionally selected and used as drying means. Regarding the drying by the dryer  38  of the sheet body  35  impregnated with the binder  37 , the present invention is not limited to cases of drying using a single dryer  38 , rather, a configuration is possible in which a plurality of dryers  38  are provided and the sheet body  35  is dried while being sequentially transported to each of the dryers  38 . 
         [0082]    The sheet body  35  that has been dried by the dryer  38  is then sequentially subjected to a folding process, a cutting process and the like as required. In the folding process, the sheet body  35  is guided to a folding machine  39  and is folded a predetermined number of times. After the folding process, the sheet body  35  is cut to predetermined dimensions and, thus, a folded body  40  of the sheet body  35  (the water absorbent article  1 ) is obtained. 
         [0083]    Note that in the manufacturing method shown in  FIG. 4 , in the housing  32  of the crusher  31 , the airflow forming mechanism F draws an air and forms an airflow to accumulate the crushed pulp  11  on the first base paper sheet  24  in a compressed state, but the method of accumulating the crushed pulp  11  on the first base paper sheet  24  is not limited to this. Moreover, an example was described in which embossing is performed on the sheet body  35  by the emboss roller  34 , but the embossing may not be necessarily performed. 
         [0084]    The water absorbent article  1  of the present invention can be used as raw materials of dry products such as tissue paper used in a non-wet state. Moreover, the water absorbent article  1 , which has superior absorbency, can be used as raw materials for wet products such as cleaning goods for cleaning around toilets; a posterior wiping material; a body wipe for wiping the body; a facial sheet, makeup remover, or toning sheet for wiping a face; a wet tissue; a wet wipe or paper rag; and a wet floor wiping sheet which are used by impregnating an antimicrobial agent, a cleaning agent, or a detersive thereon. 
       Second Embodiment 
       [0085]    Next, a configuration of a second embodiment of the absorbent article according to the present invention will be described with reference to  FIGS. 5 and 6 . 
         [0086]    A water absorbent article  51  shown in  FIGS. 5 and 6  includes a surface sheet layer  54  formed from the first surface sheet layer  52  and the second surface sheet layer  53 , and a softness imparting layer  55  is accumulated between the first surface sheet layer  52  and the second surface sheet layer  53 . With the water absorbent article  51 , a plurality of depressions  56  made by embossing are formed in an edge portion of the water absorbent article  51 . The depression  56  is a concept including what is referred to as “spot processing” in the embossing. 
         [0087]    Here, “spot processing” is a method for performing sealing of the first surface sheet layer  52  and the second surface sheet layer  53  by pressing the second surface sheet layer  53  (described below) in a spot-like manner toward the first surface sheet layer  52 . In this case, the depression  56  is formed in the surface of the second surface sheet layer  53 ; the depression  56  is not formed in the surface of the first surface sheet layer  52 , which is flat. 
         [0088]    Even with the water absorbent article  51  formed in such a manner, the water absorbent article  51  having both strength and softness as a whole can be obtained. Moreover, with the water absorbent article  51 , better feeling on the skin can be provided. Also, as in the absorbent article of the first embodiment, the water absorbent article  51  has superior absorbency. 
       Third Embodiment 
       [0089]    Next, a configuration of a third embodiment of the water absorbent article  1  according to the present invention will be described with reference to  FIG. 7 . A water absorbent article  61  shown in  FIG. 7  has a two-layer configuration in which a softness imparting layer  63  is accumulated on a surface sheet layer  62 . Note that specific configurations of the surface sheet layer  62  and the softness imparting layer  63  are the same as those described in the first embodiment. Therefore, description here is omitted. 
         [0090]    Moreover, the apparatus for manufacturing the water absorbent article  1  according to the first embodiment includes the second feeding roll  22  on which the second base paper sheet  25  for forming the second surface sheet layer  8  is wound, but a manufacturing apparatus according to the present embodiment does not include the second feeding roll  22 . Note that other configurations are the same as the first embodiment. 
         [0091]    Furthermore, a method for manufacturing the absorbent article  1  does not include the second base paper sheet laminating process. Other processes are the same as the first embodiment. 
         [0092]    Even with the water absorbent article  61  as shown in  FIG. 7 , by accumulating the softness imparting layer  63  on the surface sheet layer  62 , the overall strength and softness of the water absorbent article  61  can be increased and the bulky feel of the water absorbent article  61  can be enhanced at a low basis weight. Thus, softness and strength as a whole can be imparted and a product with better feeling on the skin can be obtained. Also, the absorbent article according to the third embodiment has superior absorbency as those in the first and second embodiments. 
         [0093]    As described above, embodiments of the absorbent article according to the present invention have been described in detail, but the description given above is an example of the absorbent article according to the present invention, and the present invention is not limited thereto. For example, it will be understood that the present invention can be used for absorbent articles such as paper diapers and sanitary articles. Moreover, in the embodiments described above, a formation was described in which embossing was performed on the surface sheet layer and the softness imparting layer, but a formation is possible in which embossing is not performed and, instead, edge portions of the surface sheet layer and the softness imparting layer are folded. 
       EXAMPLES 
     Example 1 
       [0094]    In Example 1, a first base paper sheet formed from a paper material of a size of 100 mm×100 mm, and a second base paper sheet formed from the same paper material as the first base paper sheet having a size of 100 mm×100 mm and the same weight as the first base paper sheet were used. Moreover, a pulp sheet formed from pulp material was used. Moreover, a basis weight of the pulp sheet was 30 g/m 2 . 
         [0095]    Next, the pulp sheet was crushed and, the crushed pulp formed thereafter was accumulated on the first base paper sheet. Next, the first base paper sheet on which the crushed pulp was accumulated was fed out of the crusher, and the second base paper sheet was laminated on the crushed pulp. Thereafter, embossing was performed using emboss rollers and a bulk portion was formed by forming an uneven body. Note that hereinafter, the first base paper sheet in such a accumulated/laminated formation is referred to as the “first surface sheet” and the second base paper sheet in the formation is referred to as the “second surface sheet”. 
         [0096]    Next, a binder made from carboxymethyl cellulose was sprayed from a nozzle of a spraying device onto the front and back sides of the sheet body, and an aqueous solution of zinc sulfate as a crosslinking solution was sprayed thereon, thereby impregnating the binder and the crosslinking agent into the sheet body. Thereafter, the accumulated-fiber body was dried using a dryer. 
         [0097]    Next, the aqueous solution of zinc sulfate as a crosslinking solution was sprayed on and impregnated into the dried accumulated-fiber body. Thereafter, the sheet body was folded by a folding machine and a folded absorbent article was obtained. A thickness of the obtained absorbent article was 0.17 mm. 
       Peeling Test 
       [0098]    A test was performed on the absorbent article obtained through the process described above in which the second surface sheet was peeled from the first surface sheet, and visual confirmation as to Which, of the first surface sheet and the second surface sheet, the crushed pulp constituting the softness imparting layer was adhered to was carried out. Five sample pieces of the absorbent article obtained through the process described above were prepared and all of these samples were subjected to this peeling test. As a result, when the second surface sheet was peeled, an average value of a total weight of the first surface sheet and the crushed pulp adhered to the first surface sheet was 0.49 g, and an average value of a total weight of the second surface sheet and the crushed pulp adhered to the second surface sheet was 0.23 g. Thus, the weight of the first surface sheet and the crushed pulp adhered to the first surface sheet was greater than the weight of the second surface sheet and the crushed pulp adhered to the second surface sheet. A reason for this is thought to be because the fibers of the crushed pulp are accumulated on the first surface sheet by an airflow drawn and generated from a lower side of the first base paper sheet and, as such, the fibers of the crushed pulp exist densely in a compressed state in the region of the boundary face between the first surface sheet layer and the layer of the crushed pulp; and consequently, the joining strength due to the binder between the fibers of the first surface sheet layer and the fibers of the softness imparting layer is greater than the joining strength due to the binder between the fibers of the second surface sheet layer and the fibers of the softness imparting layer. 
       Example 2 
       [0099]    In Example 2, a first base paper sheet and a second base paper sheet of the same size and thickness as in Example 1 were used. Furthermore, a water absorbent article was obtained through the same process as in Example 1. Example 2 differed from Example 1 in that the basis weight of the pulp sheet was 20 g/m 2  and the thickness of the absorbent article was 0.13 mm. 
       Peeling Test 
       [0100]    As in Example 1, in Example 2, five sample pieces of the absorbent article were prepared and all of these samples were subjected to the peeling test. As a result, when the second surface sheet was peeled, an average value of a weight of the first surface sheet and the crushed pulp adhered to the first surface sheet was 0.37 g., and an average value of a weight of the second surface sheet and the crushed pulp adhered to the second surface sheet was 0.21 g. Thus the weight of the first surface sheet and the crushed pulp adhered to the first surface sheet was greater than the weight of the second surface sheet and the crushed pulp adhered to the second surface sheet. As expected, as in Example 1, the crushed pulp is accumulated on the first surface sheet by the airflow drawn and generated from a lower side of the first base paper sheet, therefore, the fibers of the crushed pulp exist densely in a compressed state at a position near the first base paper sheet. As a result, as the entanglement between the fiber of the crushed pulp and the fiber of the surface sheet layer increases, the area contacting the binder is larger. For these reasons, it is thought that the joining strength between the crushed pulp and the surface sheet layer increases and, more of the crushed pulp remains on the first surface sheet that has a higher density than on the second surface sheet and there is a change in weight. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1 ,  51 ,  61  Water absorbent article 
           1   a  Accumulated-fiber body 
           2  Protrusion 
           3 ,  56  Depression 
           4  Emboss 
           5 ,  54 ,  62  Surface sheet layer 
           6 ,  55 ,  63  Softness imparting layer 
           7 ,  52  First surface sheet layer 
           8 ,  53  Second surface sheet layer 
           9   a,    9   b  Boundary face 
           11  Crushed pulp 
           24  First base paper sheet 
           25  Second base paper sheet 
           26  Pulp sheet 
           31  Crusher 
           32  Housing 
           33  Crushing part 
           34  Emboss roller 
           36  Bulk portion 
           37  Binder 
           38  Dryer 
           40  Folded body