US20090056867A1 - Method and device for manufacturing sheet-shaped body and method for manufacturing disposable absorbent article using the sheet-shaped body - Google Patents

Abstract

A method for manufacturing a sheet-shaped body in which a powder particle layer is sandwiched between a base sheet to which a bonding agent is applied and a covering sheet so as to be bonded into an integral body, is provided with the steps of: shifting the base sheet, the powder particle layer and the covering sheet, with each of the sheets and the layer being held on the respective roller face, and after the powder particle layer has been transferred onto the base sheet, bonding the base sheet, the powder particle layer and the covering sheet into an integral form. Thus, the powder particle layer can be fixed to a predetermined position in a stable manner.

Description

• This application is a Divisional Application of Ser. No. 10/566,533 filed Jan. 30, 2006.
TECHNICAL FIELD
• This invention relates to a method and a device for manufacturing a sheet-shaped body, and a method for manufacturing a disposable absorbent article using the sheet-shaped body.
BACKGROUND ART
• Conventionally, a device, which manufactures a sheet-shaped absorbent body in which a highly absorbent resin particle layer is sandwiched between a base sheet to which a bonding agent is applied and a covering sheet so as to be bonded into an integral body, has been proposed (for example, see International Application Laid-Open WO01/89439).
• In thePatent Document 1, highly absorbent resin particles are naturally dropped onto the base sheet to which an adhesive has been applied to be formed into a layer, and the base sheet, the highly absorbent resin particle layer and the covering sheet are bonded into an integral form so that a sheet-shaped absorbent body is manufactured.
• However, there has been such a problem that, when naturally dropping the highly absorbent resin particles, the highly absorbent resin particles bounce on the base sheet, and it becomes difficult to obtain a sheet-shaped absorbent body in which the highly absorbent resin particle layer is stably fixed onto a predetermined position.
• The present invention has been made in order to solve the above-mentioned problem, and its objective is to provide a method and a device for manufacturing a sheet-shaped body that is capable of stably fixing a powder particle layer at a predetermined position, and a manufacturing method of a disposable absorbent article using the sheet-shaped body.
DISCLOSURE OF THE INVENTION
• In order to solve the above-mentioned problem, the present invention relates to a method that manufactures a sheet-shaped body in which a powder particle layer is sandwiched between a base sheet to which a bonding agent is applied and a covering sheet so as to be bonded into an integral body, is provided with the steps of:
• shifting the base sheet, the powder particle layer and the covering sheet, with each of the sheets and the layer being held on the respective roller faces, and after the powder particle layer has been transferred onto the base sheet, bonding the base sheet, the powder particle layer and the covering sheet into an integral form.
• In accordance with this invention, since the powder particle layer is transferred onto the base sheet while being shifted in the held state on the respective roller faces, it is possible to prevent the powder particles from bouncing, which makes this method different from the system in which powder particles are allowed to naturally drop to form a layer; therefore, it becomes possible to prepare the sheet-shaped body in which the powder particle layer is stably fixed onto a predetermined position.
• In addition, since the base sheet, the powder particle layer and the covering sheet are bonded into an integral form while being shifted, with each of the sheets and the layer being held on the respective roller faces, it is possible to easily control the shifting speeds and the bonding processes of the respective materials, and also to carry out the processes even in a narrow space. Therefore, in the case when the powder particle layer is prepared as a highly absorbent resin particle layer, the manufacturing method of a sheet-shaped body is easily assembled into a continuous manufacturing line of a disposal absorbent article.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a system diagram that shows a manufacturing apparatus of a disposable absorbent article in which a manufacturing device of a sheet-shaped absorbent body is assembled.
• FIG. 2(a) is a side view showing the manufacturing device of a sheet-shaped absorbent body andFIG. 2(b) is a side view showing an essential portion of the manufacturing device of a sheet-shaped absorbent body having a protective plate member.
• FIG. 3(a) is a front view that shows a temporary receiving roller;FIG. 3(b) is an enlarged side sectional view that shows an essential portion of the temporary receiving roller;FIG. 3(c) is a plan view that shows a base sheet immediately after a highly absorbent resin particle layer has been transferred thereon;FIG. 3(d) is a side view ofFIG. 3(c);FIG. 3(e) is a plan view that shows the base sheet immediately after the highly absorbent resin particle layer has been linearly aligned; andFIG. 3(f) is a side view ofFIG. 3(e).
• FIGS. 4(a) to4(h) are plan views of base sheets on which highly absorbent resin particle layers having patterns of respective types have been transferred.
• FIGS. 5(a) and5(b) show a sheet-shaped absorbent body;FIG. 5(a) is a plan view; andFIG. 5(b) is an enlarged sectional view taken along line D-D ofFIG. 5(a).
• FIGS. 6(a) and6(b) show a disposable absorbent article;FIG. 6(a) is a plan view; andFIG. 6(b) is an enlarged sectional view taken along line E-E ofFIG. 6(a).
• FIG. 7(a) is a side view of a manufacturing device of a sheet-shaped absorbent body constituted by a plurality of layers, andFIG. 7(b) is a sectional view showing the sheet-shaped absorbent body constituted by a plurality of layers.
BEST MODE FOR CARRYING OUT THE INVENTION
• The invention relates to a manufacturing method of a sheet-shaped body which includes the step of transferring the powder particle layer onto the base sheet, with the powder particle layer being shifted in the same direction as the base sheet. In accordance with the invention, since the powder particle layer is transferred onto the base sheet while being shifted in the same direction as the base sheet, it becomes possible to smoothly transfer the powder particle layer, with the powder particle layer being kept free from bouncing.
• The invention relates to a manufacturing method of a sheet-shaped body which is designed so that the shifting speeds of the base sheet, the powder particle layer and the covering sheet are set to the same speed or the shifting speed of the powder particle layer is made slower. In accordance with the invention, since the base sheet, the powder particle layer and the covering sheet are shifted at the same speed or since the powder particle layer is shifted at a slower speed; therefore, it becomes difficult for the powder particle layer to flow at the same speed so that the sheet-shaped body in which the powder particle layer is stably fixed at a predetermined position can be obtained.
• The invention is designed so that the process for transferring the powder particle layer on the base sheet and the process for bonding the covering sheet are carried out on the same roller face. In accordance with the invention, since the covering sheet is bonded in a short time after the powder particle layer has been transferred onto the base sheet, the powder particle layer can be enclosed between two sheets quickly so that the sheet-shaped body in which the powder particle layer is stably fixed at a predetermined position can be obtained. In addition, the processes can be carried out even in a narrow space; therefore, even in the case when the powder particle layer is prepared as a highly absorbent resin particle layer, the manufacturing device for the sheet-shaped body is easily assembled into a continuous manufacturing line of a disposable absorbent article.
• In accordance with the invention, since the powder particle layer is made of a highly absorbent resin particle layer, the sheet-shaped body is constituted by a sheet-shaped absorbent body.
• Here, the powder particle body refers to a solid substance having a grain size (dimension) in which at least one powder particle body is allowed to enter a square cubic body having 3 mm square without a change in its shape. With respect to the shape thereof, not particularly limited, any shape, such as a thin film shape and a fiber shape, may be used as long as the size is set as described above. In addition, with respect to the fluidity index, the substance is set to a value of 40 or more. The substance needs to have an electrically and chemically stable state in which none of adhesion, bonding, aggregation and cross-linking occur between the particles as well as between the particles and substances derived from the particle transferring process, due to an intermolecular force, a magnetic force, a chemical reaction and the like.
• With respect to the powder particle body, for example, a highly absorbent resin particle layer for use in a sheet-shaped absorbent body is used in the present embodiment; however, by using the following materials as the powder particle body, the resulting sheet-shaped body can be used for other applications.
• The material for the powder particle body include, for example, asphalt, aluminum, aluminum chloride, potassium chloride, calcium chloride, iron pyrite, activated charcoal, clay (kaolin), synthetic wax, acetic acid fiber elements, zinc oxide, iron oxide, CMC acid, salts, barite, sodium bicarbonate, ammonium nitrate, sirasu balloons, magnesium hydroxide, barium stearate, sands, zeolite, sodium sesquicarbonate, limestone, plaster, talc, tungsten carbide, zinc carbonate, potassium carbonate, starch, toner, lead, urine, malt, sodium pyrophosphate, phosphate rock, powdered aluminum oxide, borax, fluorite, bauxite, polyethylene pellets, polystyrene, polyvinyl chloride, mirabilite, anthracite, wood powder, calcined plaster, oil rock, ammonium sulfate, sodium sulfate, calcium dihydrogen phosphate, calcium hydrogen phosphate, tricalcium phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate and trisodium phosphate, and, these material may be properly selected accordingly depending on the applications. For example, the sheet-shaped body using activated charcoal or zeolite as the powder particle body is applied as a deodorant sheet used for removing offensive stenches of excrements from human bodies and animals. In addition, the sheet-shaped body using limestone as the powder particle body can be buried in soils of rice fields or other fields so as to serve as a fertilizer sheet.
• The invention, which relates to a device for manufacturing a sheet-shaped body in which a powder particle layer is sandwiched between a base sheet to which a bonding agent is applied and a covering sheet so as to be bonded into an integral body, is provided with:
• a receiving and transferring roller that shifts the base sheet with the base sheet being held on its roller face, a temporary receiving roller that transfers the powder particle layer onto the base sheet, while shifting the powder particle layer, with the powder particle layer being held on its roller face, and a contact-bond fixing roller that bonds the base sheet, the powder particle layer and the covering sheet into an integral form, while shifting the covering sheet with the covering sheet being held on its roller face. In accordance with the invention, since the powder particle layer is transferred onto the base sheet while being shifted in the held state on the roller face, it is possible to prevent the powder particles from bouncing, which makes this device different from the system in which powder particles are allowed to naturally drop to form a layer; therefore, it becomes possible to prepare a sheet-shaped absorbent body in which the powder particle layer is stably fixed onto a predetermined position.
• In addition, since the base sheet, the powder particle layer and the covering sheet are bonded into an integral form while being shifted, with each of the sheets and the layer being kept contact with the respective roller faces, it is possible to easily control the shifting speeds and the bonding processes of the respective materials, and also to carry out the processes even in a narrow space. Therefore, in the case when the powder particle layer is prepared as a highly absorbent resin particle layer, the manufacturing device of the sheet-shaped body is easily assembled into a continuous manufacturing line of a disposable absorbent article.
• The invention, which relates to the device, has a structure in which: the surface peripheral velocities of the receiving and transferring roller, the temporary receiving roller and the contact-bond fixing roller are set to the same speed, or the surface peripheral velocity of the temporary receiving roller is set to be slower. In accordance with the invention, since the surface peripheral velocities of the receiving and transferring roller, the temporary receiving roller and the contact-bond fixing roller are set to the same speed, or since the surface peripheral velocity of the temporary receiving roller is set to be slower, it becomes difficult for the powder particle layer to flow at the same speed so that the sheet-shaped body in which the powder particle layer is stably fixed at a predetermined position can be obtained, and since the respective materials, which are shifted in the held state on the respective rollers, are allowed to shift at the same peripheral velocity, it becomes possible to easily carry out the controlling process.
• The invention, which relates to the device, has a structure in which concave grooves that receive the powder particle layer and shifts the powder particle layer while being held in a layer form are formed on the roller face of the temporary receiving roller. In accordance with the invention, since the powder particle layer, which is received by the concave grooves and held in a layer form, is transferred onto the base sheet, it becomes possible to prevent the powder particles from bouncing, which makes this structure different from the system in which powder particles are allowed to naturally drop to form a layer; therefore, it becomes possible to prepare a sheet-shaped body in which the powder particle layer is stably fixed onto a predetermined position. Here, since the concave grooves hold the powder particle layers individually, it is possible to prevent the powder particles from being spilled from the concave grooves, even when the concave grooves are directed laterally or upside down following the rotation of the temporary receiving roller, and consequently to prevent the powder particles from contaminating around the device.
• The invention, which relates to the device, has a structure in which a guide member used for maintaining the powder particle layer is installed therein in a manner so as to face the roller face of the temporary receiving roller. In accordance with the invention, the receiving openings of the concave grooves are sealed with the guide member so that the powder particle layer can be transferred onto the base sheet in a state in which the powder particle layer is enclosed into the concave grooves; therefore, it becomes possible to prevent the powder particles from bouncing, which makes this structure different from the system in which powder particles are allowed to naturally drop to form a layer, and consequently to prepare a sheet-shaped body in which the powder particle layer is stably fixed onto a predetermined position. In addition, it is possible to prevent the powder particles from being spilled from the concave grooves, and consequently to prevent the powder particles from contaminating around the device.
• The invention, which relates to the device, has a structure in which at least one of the contact-bond fixing roller and the receiving and transferring roller is a heat roller. In accordance with the invention, a partially fusing process between the sheets caused by heat can be carried out, and it becomes possible to eliminate the necessity of installing a heat roller separately, and consequently to make the device space compacter as well as making the device more easily controlled; therefore, in the case when the powder particle layer is prepared as a highly absorbent resin particle layer, the manufacturing device of the sheet-shaped body is easily assembled into a continuous manufacturing line of a disposable absorbent article.
• The invention, which relates to the device, has a structure in which a press contact roller which presses the covering sheet to be in contact with the base sheet on the receiving and transferring roller is installed before the contact-bond fixing roller. In accordance with the invention, immediately after the powder particle layer has been transferred on the base sheet, the base sheet is covered with the covering sheet that is made in press-contact thereto by the press contact roller; therefore, the powder particle layer is prevented from flowing so that a sheet-shaped body in which the powder particle layer is stably fixed at a predetermined position can be obtained.
• The invention, which relates to the device, has a structure in which a protective plate member, which prevents the powder particle layer from flowing, is attached to the receiving and transferring roller. In accordance with the invention, it is possible to prevent the powder particle layer from flowing by the protective plate member during a period from the transfer of the powder particle layer onto the base sheet until the covering sheet has been placed and press-secured thereon by the contact-bond fixing roller; therefore, it becomes possible to obtain a sheet-shaped body in which the powder particle layer is stably fixed at a predetermined position.
• The invention ofclaim13, which relates to the device, features that the distance between the surface of the receiving and transferring roller and the protective plate member is set in a range from 0.5 to 5 mm. In accordance with the invention, since the distance between the surface of the receiving and transferring roller and the protective plate member is set in a range from 0.5 to 5 mm, it becomes possible to positively prevent the powder particle layer from flowing.
• The invention, which relates to the device, features that the powder particle layer is a highly water-absorbent resin particle layer. In accordance with the invention, since the powder particle layer is prepared as a highly water-absorbent resin particle layer, the sheet-shaped body is obtained as a sheet-shaped absorbent body. Here, the grain size, kinds and the like of the powder particle layer are the same as those explained in the invention.
• The invention features that the sheet-shaped body is sandwiched between a liquid-permeable top sheet and a liquid-impermeable back sheet to be bonded into an integral form so that a disposable absorbent article is produced. In accordance with the invention, it is possible to produce a disposable absorbent article having a sheet-shaped absorbent body in which the highly water-absorbent resin particle layer is stably fixed at a predetermined position.
• Referring to Figures, the following description will discuss the preferred mode for carrying out the invention in detail.
EXAMPLE 1
• FIG. 1 is a system drawing that shows a continuous manufacturing apparatus of a disposable absorbent article2 (seeFIG. 6) in which a manufacturing device of a sheet-shaped water-absorbent body1 (seeFIG. 5) is incorporated.
• In the continuous manufacturing line of the disposableabsorbent article2, acarrier sheet3 is drawn from a roll body on the right side of the Figure in the length direction (leftward) A so as to be continuously drawn out.
• In process (1), a hot-melt bonding agent is applied to the upper face of thecarrier sheet3 by a hot-melt bonding-agent applying device4.
• In process (2),fibers6 mixed with highly water-absorbent resin particles are blown to the circumferential face of apattern drum5 to be laminated thereon, and thislaminated fiber aggregate7 is continuously carried on the upper face of thecarrier sheet3 at the position of asuction conveyor8 to be bonded thereon.
• Process (3) is a process for continuously manufacturing the sheet-shaped water-absorbent body1, which will be described later in detail, and in this process (3), as shown inFIG. 5, the sheet-shaped water-absorbent body1 in which a highly water-absorbentresin particle layer12 is intermittently sandwiched between abase sheet10 and acovering sheet11 in the width direction to be bonded into an integral form is continuously manufactured.
• In process (4), the sheet-shaped water-absorbent body1 with a lower face (facing the fiber aggregate7) coated with a hot-melt bonding agent is contact-bonded by apress roller13 with its lower face placed on the upper face of thefiber aggregate7 to be bonded into an integral form; thus, anabsorbent body17 is continuously manufactured.
• In process (5), theabsorbent body17 is cut into a predetermined length by amat cutter14, and then carried on atransport conveyor15 having a high speed to be shifted while being adjusted to a pitch P for each single article of disposableabsorbent articles2.
• In process (6), a hot-melt bonding agent is applied to an inner face of a liquid-impermeable back sheet18 drawn from the roll body by a hot-melt bondingagent applying device20, and theabsorbent body17 is intermittently placed on the inner face of thisback sheet18, and bonded thereto.
• In addition, a hot-melt bonding agent is applied to the inner face of a liquid-permeable top sheet19 drawn from a roll body by a hot-melt bondingagent applying device21, and the inner face of the back sheet21 (face facing the absorbent body17) is placed on the upper face of theabsorbent body17 so that theabsorbent body17 is sandwiched between theback sheet18 and thetop sheet19 to be bonded into an integral form; thus, a disposableabsorbent article2 can be continuously manufactured.
• Although the succeeding processes are not shown in Figures, theback sheet18 and thetop sheet19 are cut for each single article of disposableabsorbent articles2, and each article is double-folded or triple-folded in the length direction to be made compacter; thus, the resulting articles are packaged for each of predetermined number thereof.
• In the continuous manufacturing apparatus of the disposableabsorbent articles2 ofFIG. 1, theabsorbent body17 is manufactured by combining the sheet-shaped water-absorbent body1 and thefiber aggregate7; however, theabsorbent body17 may be formed by using only the sheet-shaped water-absorbent body1, without using thefiber aggregate7.
• In addition, the manufacturing device of the sheet-shaped water-absorbent body1 is incorporated into the continuous manufacturing apparatus of the disposableabsorbent article2; however, the manufacturing apparatus of the disposableabsorbent article2 and the manufacturing device of the sheet-shaped water-absorbent body1 may be installed in places (factories) separated from each other. In this case, the sheet-shaped water-absorbent body1 is supplied as a roll body in process (4).
• Referring toFIG. 2(a), the following description will discuss process (3) for manufacturing the sheet-shaped water-absorbent body1 in detail.
• The manufacturing device of the sheet-shaped water-absorbent body1, which is incorporated in aframe member26, has a structure in which: atemporary receiving roller27 is attached to the upper portion of thisframe member26; a receiving and transferringroller28 is attached to the lower portion thereof; and a contact-bond fixing roller29 is attached to the right side thereof, with thetemporary receiving roller27 and the receiving and transferringroller28 being made close to each other vertically, as well as with the receiving and transferringroller28 and the contact-bond fixing roller29 being made close to each other horizontally. The distance between thetemporary receiving roller27 and the receiving and transferringroller28 is preferably set to 3 mm or less, more preferably, to 1 mm.
• Thetemporary receiving roller27 is rotated counterclockwise, the receiving and transferringroller28 is rotated clockwise, and the contact-bond fixing roller29 is rotated counterclockwise, and in this arrangement, the respective surface peripheral velocities are set to the same speed, or thetemporary receiving roller27 is set to a slightly lower velocity. In other words, therespective rollers27 to29 are basically set to the same peripheral velocity; however, with respect to thetemporary receiving roller27, its surface peripheral velocity is variably determined so as to be set to a surface velocity slightly lower than that of theother rollers28 and29. The reason for this will be described later.
• As shown in the front view ofFIG. 3(a), rows of a plurality of concave grooves (four in this example)27a, which extend along the circumference of the roller face with a predetermined interval t1 in the roller length direction, are formed in the roller surface of thetemporary receiving roller27, and as shown in the side sectional view showing an essential portion ofFIG. 3(b), each of theconcave grooves27ais formed so as to have intermittent portions (cells) with a predetermined interval t2 along the circumference of the roller face (rotation shifting direction). Eachconcave groove27ahas abottom face27bformed into an arc shape along the circumference of the roller face.
• Eachconcave groove27ais used for receiving highly water-absorbent resin particles12′ and for shifting these while being held in a layer state. Here, when concave grooves having the same pattern as thetemporary receiving roller27 are also formed on the roller face of the receiving and transferringroller28, the highly water-absorbent resin particles12′ can be stably transferred so that it is possible to prevent the resin particles from scattering on the periphery.
• Abox31 that supplies the highly water-absorbent resin particles12′ to each of theconcave grooves27aof the roller face is placed above thetemporary receiving roller27, and an arc-shapedguide member32, used for holding the highly water-absorbentresin particle layer12 that has been supplied to each of theconcave grooves27aand formed into a layer, is installed in a manner so as to face the roller face of thetemporary receiving roller27 located from thebox31 to the roller face of the receiving and transferringroller28. Here, a tank that stores the highly water-absorbent resin particles12′ may be connected to the upper portion of thebox31.
• The gap between thetemporary receiving roller27 and theguide member32 is preferably set to 1 mm or less, more preferably, to 0.2 mm or less. Thetemporary receiving roller27 and theguide member32 are preferably made of a metal material having high hardness. Since the highly water-absorbent resin particles12′ are always made in contact with these, these members are subjected to severe abrasion. With respect to the metal material of thetemporary receiving roller27, SKH51 having hardness in a range of HRC61±1 is preferably used, and with respect to the metal material of theguide member32, SKH51 having hardness in a range of HRC63±1 is preferably used.
• Thebase sheet10, which has been drawn from a roll body in the length direction so as to be continuously shifted, has its upper face (inner face) coated with a hot-melt bonding agent by a hot-melt bonding agent applying device33 (seeFIG. 1), and is then directed downward with its lower face (outer face) being made in contact with the roller face of the receiving and transferringroller28 from the left side so as to be wound around the roller face of the receiving and transferringroller28. In other words, thebase sheet10 is shifted in a held (wrapped) state on the roller face of the receiving and transferringroller28.
• The highly water-absorbent resin particles12′ are supplied from thebox31 to each of theconcave grooves27aof the roller face of thetemporary receiving roller27. At this time, since a scrapingmember34 is attached to a wall portion on the downstream side in the rotation direction inside thebox31, the excessive portion of the highly water-absorbent resin particles12′ beyond the capacity of each of theconcave grooves27ais scraped off so that a fixed amount of the highly water-absorbent resin particles12′ corresponding to the amount that just makes full of each of theconcave grooves27ais received.
• The highly water-absorbentresin particle layer12 that has been received by each of theconcave grooves27ato be formed into a layer, is shifted directly above thebase sheet10 wrapped on the roller face of the receiving and transferringroller28, while being held inside each of theconcave grooves27aby theguide member32, so that simultaneously with the coming off from theend32aof theguide member32, it is transferred onto the upper face of thebase sheet10 coated with the hot-melt bonding agent. In other words, the highly water-absorbentresin particle layer12 is shifted in a held state on the roller face of thetemporary receiving roller27.
• Immediately after the transferring process, the highly water-absorbentresin particle layer12 forms a square shape, with its distances t1 and t2 being kept vertically as well as laterally, as shown inFIGS. 3(c) and3(d), and in this case, when the interval t2 is made narrower, as shown inFIGS. 3(e) and3(f), it is allowed to form a linear shape in the shifting direction of thebase sheet10 with the interval t1 being intermittently kept in the width direction in the course of the shift.
• InFIGS. 3(a) and3(b), since the square-shapedconcave grooves27aare placed vertically as well as horizontally, the highly water-absorbentresin particle layer12 forms a square shape immediately after the transferring process, as shown inFIG. 4(a) for use in comparison; however, whenconcave grooves27a, each having a laterally elongated rectangular shape, are placed in the vertical direction, the highly water-absorbentresin particle layer12 is allowed to form a laterally elongated rectangular shape as shown inFIG. 4(b) immediately after the transferring process.
• In the same manner, as shown inFIG. 4(c), when each of theconcave grooves27ais formed into a ring shape, the highly water-absorbentresin particle layer12 is also made into the same shape; as shown inFIG. 4(d), whenconcave grooves27a, each having a square shape, are combined into a ring shape, the highly water-absorbentresin particle layer12 is also made into the same shape; as shown inFIG. 4(e), whenconcave grooves27aare formed into an X-shape, the highly water-absorbentresin particle layer12 is also made into the same shape; and as shown inFIG. 4(f), whenconcave grooves27a, each having a square shape, are combined into an X-shape, the highly water-absorbentresin article layer12 is also made into the same shape. Although not shown in Figures, each of theconcave grooves27amay be made into a lozenge or an elliptical shape, and theconcave grooves27amay be arranged in a snaking format around the roller circumferential face (rotation shifting direction).
• In this manner, it is possible to form highly water-absorbent resin particle layers12 having various patterns by appropriately selecting the shape of theconcave grooves27a.
• As described above, in the case when the interval t2 is made narrower, the highly water-absorbentresin particle layer12 is formed into a linear shape in the shifting direction of thebase sheet10 with an interval t1 being intermittently kept in the width direction in the course of a shift as shown inFIGS. 3(e) and3(f), and with respect to thetemporary receiving roller27, by setting the surface peripheral velocity to a level slightly slower than that of theother rollers28 and29, the highly water-absorbentresin particle layer12 is formed into a linear shape in the shifting direction of thebase sheet10 with an interval t1 being intermittently kept in the width direction as shown inFIG. 4(g) in the example ofFIG. 4(a), in the same manner asFIGS. 3(e) and3(f); and, in the example ofFIG. 4(b), it is also formed into a linear shape in the shifting direction of thebase sheet10, as shown inFIG. 4(h). Here, with respect to cases shown inFIGS. 4(c),4(d),4(e) and4(f) as well, it is possible to provide a pattern that is blurred in the shifting direction. Here, the amount of the highly water-absorbent resin particles12′ to be transferred onto thebase sheet10 is determined by the capacity of each of theconcave grooves27aso that by adjusting the capacity of theconcave groove27a, the degree of the blurred state in the shifting direction of a pattern can be changed.
• The coveringsheet11, drawn from a roll body so as to be continuously shifted, has its upper face (inner face) coated with a hot-melt bonding agent by a hot-melt bonding agent applying device35 (seeFIG. 1), and is then wound around the roller face of the contact-bond fixing roller29 in a manner so as to be drawn downward with its lower face (outer face) being made in contact with the roller face of the contact-bond fixing roller29 from the right side. In other words, the coveringsheet11 is shifted in the held (wrapped) state around the roller face of the contact-bond fixing roller29.
• Then, thebase sheet10 on which the highly water-absorbentresin particle layer12 has been transferred and the coveringsheet11 are joined between the receiving and transferringroller28 and the contact-bond fixing roller29 so that a sheet-shaped water-absorbent body1 in which the highly water-absorbentresin particle layer12 is sandwiched between thebase sheet10 and the coveringsheet11 by the contact bonding process of the contact-bond fixing roller29 to be bonded into an integral form is continuously manufactured.
• The sheet-shaped water-absorbent body1 thus continuously manufactured has its lower face (facing the fiber aggregate7) coated with a hot-melt bonding agent by a hot-melt bonding agent applying device36 (seeFIG. 1) as explained in process (4), and is then placed on the upper face of thefiber aggregate7.
• The contact-bond fixing roller29, which forms a heat roller, has a structure in which a step portion is formed on the roller face of the contact-bond fixing roller29 so that the two ends of thebase sheet10 and the coveringsheet11 are melt-bonded, with the adjacent highly water-absorbent resin particle layers12 being also melt-bonded to each other; thus, as shown inFIG. 5(b), a sealingportion1ais formed on the sheet-shaped water-absorbent body1. Here, the receiving and transferringroller28 is also preferably prepared as a heat roller.
• Thebase sheet10 on which the highly water-absorbentresin particle layer12 is preferably joined to thecovering sheet11 as soon as possible to be bonded into an integral form so that the highly water-absorbentresin particle layer12 is desirably fixed at a predetermined position quickly in a stable manner.
• For this reason, as shown inFIG. 2(a), apress contact roller38, used for pressing thecovering sheet11 onto thebase sheet10 on the receiving and transferringroller28, is preferably installed at a position prior to the contact-bond fixing roller29 between thetemporary receiving roller27 and the contact-bond fixing roller29. Thispress contact roller38 is supported by apiston rod39aof a hydraulic cylinder (or an air-pressure cylinder may be used; hereinafter, the same is true)39, and the covering sheet [reference numeral (11)] is wound around thepress contact roller38, and immediately after having been released between thetemporary receiving roller27 and the receiving and transferringroller28, the coveringsheet11 is pressed onto thebase sheet10 on which the highly water-absorbentresin particle layer12 has been transferred, to cover thereon. Thereafter, by the contact bonding process of the contact-bond fixing roller29, the highly water-absorbentresin particle layer12 is sandwiched between thebase sheet10 and the coveringsheet11, and bonded into an integral form. Here, thepress contact roller38 is adjusted in its press-contacting force by thehydraulic cylinder39 so that with respect to the highly water-absorbentresin particle layer12 to be transferred onto the upper face of thebase sheet10, the thickness thereof, which is varied depending on the amount of the highly water-absorbentresin particle layer12, is properly adjusted. Here, the step portion to form the sealingportion1amay be formed on the roller face of thepress contact roller38 instead of being formed on the contact-bond fixing roller29. Thepress contact roller38 is preferably designed to have a diameter of about 14 mm.
• As shown inFIG. 2(b), in place of thepress contact roller38, an arc-shapedprotective plate member40, which is located close to the roller face of the receiving and transferringroller28 with a predetermined interval t3, may be installed.
• Thisprotective plate member40 is used for preventing the highly water-absorbentresin particle layer12 from flowing during a period from the transferring process of the highly water-absorbentresin particle layer12 onto thebase sheet10 until the press contacting and fixing processes of the coveringsheet11 thereon by using the contact-bond fixing roller29. The distance t3 between the roller face of the receiving and transferringroller28 and theprotective plate member40 is preferably set in a range from 0.5 to 5 mm.
• By the use of thisprotective plate member40, it becomes possible to obtain a sheet-shaped water-absorbent body1 with the sheet being stably fixed on a predetermined position. When the above-mentioned distance t3 is less than 0.5 mm, the distance is too narrow, with the result that the highly water-absorbent resin particles12′ tend to clog or the hot-melt bonding agent on the inner face (upper face) of thebase sheet10 tends to adhere to theprotective plate member40 making it difficult to carry out controlling processes; in contrast, when it exceeds 5 mm, it becomes impossible to achieve the objective of preventing the highly water-absorbentresin particle layer12 from flowing.
• FIG. 5 show a sheet-shaped water-absorbent body1 continuously manufactured in the above-mentioned process (3), andFIG. 5(a) is a plan view thereof, andFIG. 5(b) is an enlarged sectional view taken along line D-D ofFIG. 5(a).
• The sheet-shaped water-absorbent body1 has a structure in which the highly water-absorbentresin particle layer12 is sandwiched between thebase sheet10 and the coveringsheet11 and bonded into an integral form, with the sealingportions1abeing formed between the adjacent highly water-absorbent resin particle layers12. Here,reference numeral33arepresents a hot-melt bonding agent layer that is applied onto thebase sheet10 by a hot-melt bondingagent applying device33, and reference numeral35arepresents a hot-melt bonding agent layer applied onto the coveringsheet11 by a hot-melt bondingagent applying device35.
• Thebase sheet10 and the coveringsheet11 are preferably formed by liquid-permeable non-woven fabric materials. Examples of the non-woven fabric materials include: hydrophilic fibers (cotton, rayon, cellulose, etc.), fibers prepared by subjecting hydrophobic fibers (polyethylene, polypropylene, polyethylene terephthalate, nylon, polyamide, etc.) to a hydrophilic-property applying treatment by using a surfactant or the like, and mixed fibers of these fibers.
• The highly water-absorbentresin particle layer12 is formed by using conventionally known highly water-absorbent resin particles utilized as disposable absorbent articles, such as polyacrylic-acid salt based, cellulose-based, starch-based, polyacrylonitrile-based, polyamide-based and polyamino-acid-based particles. The particle size is preferably set to a size from 37 to 1000 mm, in particular, from 150 to 700 mm, in particles of 90% by mass or more of the entire mass.
• With respect to the hot-melt bonding agent, conventionally known hot-melt bonding agents, such as olefin-based, rubber-based and EVA-based hot-melt bonding agents, may be utilized, and among these, rubber-based hot-melt bonding agents, which have superior flexibility, are preferably used. With respect to the coating method, conventionally known coating methods, such as coater-coating, beads-coating, spiral-coating, melt-blow-coating and omega-coating methods, may be utilized, and among these, the spiral-coating method is preferably used for a hot-melt bonding agent to be applied to thebase sheet10, since this method hardly intervenes with the absorbing speed, while the melt-blow-coating method is also preferably used for a hot-melt bonding agent to be applied to thecovering sheet11, since this method improves the fixing stability.
• Thefiber aggregate7 forms an absorbing body that is normally used as a disposable absorbent article in which highly absorbent resin particles are mixed in hydrophilic fibers (mainly, pulverized pulp fibers) and formed into a predetermined shape, and covered with tissue paper or liquid-permeable non-woven fabric.
• FIG. 6 show a disposableabsorbent article2 that is continuously manufactured in the above-mentioned process (5); andFIG. 6(a) is a plan view andFIG. 6(b) is an enlarged sectional view taken along line E-E ofFIG. 6(a).
• The disposableabsorbent article2 has a urine-absorbing pad type in which theabsorbent body17 is sandwiched between aback sheet18 and atop sheet19 and bonded into an integral form, and on both sides of the disposableabsorbent article2, risingflaps42, each having an adjacentelastic member42a, may be placed. In addition, the disposableabsorbent article2 may have a shape such as a gourd shape so as to be well fitted to a wearer's body form.
• In addition, a tape-type disposable absorbent article with a fastening tape or a shorts-type disposable absorbent article in which expansion elastic members are formed along a waist opening portion and right and left two leg openings may be used.
• Theback sheet18 is preferably formed by a liquid-impermeable film material, a water-repellent non-woven fabric material or a composite material of these, and thetop sheet19 is preferably formed by a liquid-permeable non-woven fabric material.
• The rising flaps42 are preferably formed by a water-repellent non-woven fabric material.
• With respect to the above-mentionedelastic member42a, conventionally-known elastic materials utilized as disposable absorbent articles, such as polyurethane threads, polyurethane films and natural rubber, may be used.
• In the case when the above-mentioned manufacturing device of the sheet-shaped water-absorbent body1 is used, the receiving and transferringroller28 that transfers thebase sheet10 which is being held on its roller face, thetemporary receiving roller27 that transfers the highly water-absorbentresin particle layer12 on thebase sheet10 while shifting it in a held state on its roller face, and a contact-bond fixing roller29 that bonds thebase sheet10, the highly water-absorbentresin particle layer12 and the coveringsheet11 into an integral form while shifting the coveringsheet11 in a held state on its roller face are installed so that the highly water-absorbentresin particle layer12 is transferred on thebase sheet10, while being shifted in the held state on its roller face; therefore, it becomes possible to prevent the highly water-absorbent powder particles12′ from bouncing, which makes this device different from the system in which highly water-absorbent powder particles12′ are allowed to naturally drop to form a layer, and consequently to prepare the sheet-shaped water-absorbent body1 in which the highly water-absorbentresin particle layer12 is stably fixed onto a predetermined position.
• In addition, since thebase sheet10, the highly water-absorbentresin particle layer12 and the coveringsheet11 are bonded into an integral form while being shifted in the respective held states on roller faces, the shifting speeds and the bonding processes of therespective materials10 to12 can be easily controlled, and the processes can also be carried out even in a narrow space; therefore, the manufacturing device is easily assembled into a continuous manufacturing line of the disposableabsorbent article2
• Furthermore, in the arrangement in which the surface peripheral velocities of the receiving and transferringroller28, thetemporary receiving roller27 and the contact-bond fixing roller29 are set to the same speed, since therespective materials10 to12 that are shifted in the held states on therespective rollers27 to29 are shifted at the same speed, it becomes difficult for the highly water-absorbentresin particle layer12 to flow so that the sheet-shaped water-absorbent body1 in which the powder particle layer is stably fixed at a predetermined position can be obtained, and it becomes possible to easily carry out the controlling process. In particular, in the case when the manufacturing device of the sheet-shaped water-absorbent body1, which has been incorporated into the manufacturing apparatus of the disposableabsorbent article2, is used, the manufacturing apparatus of the disposableabsorbent article2 tends to be fluctuated in its manufacturing speed due to influences of factors other than the sheet-shaped water-absorbent body1; therefore, by providing more parts that can be controlled at the same peripheral velocity, it becomes possible to carry out driving operations easily and also to stabilize the product quality.
• In addition, since the water-absorbentresin particle layer12 is transferred onto thebase sheet10 while being shifted in the same direction as thebase sheet10, the highly water-absorbentresin particle layer12 can be smoothly transferred while preventing the highly water-absorbent resin particles12′ from bouncing.
• Furthermore, since the coveringsheet11 can be bonded in a short time after the highly water-absorbentresin particle layer12 has been transferred onto thebase sheet10, the highly water-absorbentresin particle layer12 can be quickly sealed between twosheets10 and11 so that it becomes possible to obtain the sheet-shaped water-absorbent body1 in which the resin particle layer is stably fixed at a predetermined position.
• In addition, since the highly water-absorbent resin particles12′, which are received by theconcave grooves27aand held in a layer form, are transferred onto thebase sheet10, it becomes possible to prevent the highly water-absorbent resin particles12′ from bouncing, which makes this structure different from the system in which powder particles are allowed to naturally drop to form a layer; therefore, it becomes possible to prepare the sheet-shaped water-absorbent body2 in which the highly water-absorbentresin particle layer12 is stably fixed onto a predetermined position. Here, since theconcave grooves27ahold the highly water-absorbent resin particles12′ individually, it is possible to prevent the highly water-absorbent resin particles12′ from being spilled from theconcave grooves27a, even when theconcave grooves27aare directed laterally or upside down following the rotation of thetemporary receiving roller27, and consequently to prevent the resin particles from contaminating the periphery of the device.
• In addition, upon transferring the highly water-absorbentresin particle layer12 onto thebase sheet10, the total amount thereof can be transferred without a residual highly water-absorbentresin particle layer12 in the bottom portion of eachconcave groove27a.
• Furthermore, the highly water-absorbentresin particle layer12 can be transferred onto thebase sheet10, with the resin particle layer being enclosed inside theconcave grooves27aby sealing the receiving opening of theconcave grooves27awith theguide member32 so that the highly water-absorbent resin particles12′ can be prevented from bouncing, which makes this system different from the system of forming a layer by utilizing natural drops; therefore, it becomes possible to obtain a sheet-shaped water-absorbent body1 in which the highly water-absorbentresin particle layer12 is stably fixed at a predetermined position. In addition, it is also possible to prevent the highly water-absorbent resin particles12′ from spilling out of theconcave grooves27aand consequently contaminating the periphery of the device.
• Since the contact-bond fixing roller29 is prepared as a heat roller (the receiving and transferringroller28 may also be prepared as a heat roller), thesheets10 and11 can be partially melt-bonded to each other through heat, and it becomes unnecessary to install a heat roller separately; therefore, the device space is made compacter, making it possible to easily carry out the controlling operations, and consequently to easily assemble the manufacturing device of the sheet-shaped absorbent body is easily assembled into a continuous manufacturing line of the disposal absorbent article.
• In addition, with the arrangement in which thepress contact roller38 is installed, immediately after having been transferred onto thebase sheet10, the resulting highly water-absorbentresin particle layer12 is covered with the coveringsheet11 and subjected to a press-contacting process; therefore, it becomes possible to prevent the highly water-absorbentresin particle layer12 from flowing, and consequently to obtain the sheet-shaped water-absorbent body1 in which the resin particle layer is stably fixed at a predetermined position.
• Furthermore, by assembling the above-mentioned manufacturing device of the sheet-shaped water-absorbent body1 into the continuous manufacturing apparatus of the disposableabsorbent article2, it is possible to stably manufacture the disposableabsorbent article2 having the sheet-shaped water-absorbent body1 in which the highly water-absorbentresin particle layer12 is stably fixed to a predetermined position quickly, and also to manufacture the sheet-shaped water-absorbent body1 through an in-line system; therefore, it becomes possible to provide the disposableabsorbent article2 having the sheet-shaped water-absorbent body1 at a low price.
EXAMPLE 2
• FIG. 7(a) shows a manufacturing device of a sheet-shaped water-absorbent body44 composed of a plurality of layers, andFIG. 7(b) is a sectional view of the sheet-shaped water-absorbent body44 composed of a plurality of layers.
• As shown inFIG. 7(a), abase sheet10 is coated with a hot-melt bonding agent or the like in its inner face by a hot-melt bonding-agent applying device33, and then are held on a base-sheet side receiving and transferring roller28(A), and highly water-absorbent resin particles12′, supplied from a base-sheet side box31(A), are held on a base-sheet side temporary receiving roller27(A) so that the resulting highly water-absorbentresin particle layer12, formed into a layer state, is transferred onto thebase sheet10.
• A coveringsheet11 is coated with a hot-melt bonding agent or the like in its inner face by a hot-melt bonding-agent applying device35, and then are held on a coating-sheet side receiving and transferring roller28(B), and highly water-absorbent resin particles12′, supplied from a coating-sheet side box31(B), are held on a coating-sheet side temporary receiving roller27(B) so that the resulting highly water-absorbentresin particle layer12, formed into a layer state, is transferred onto the coveringsheet11.
• Anintermediate sheet45 is interpolated between thebase sheet10 of the base-sheet side receiving and transferring roller28(A) and the coveringsheet11 of the coating-sheet side receiving and transferring roller28(B).
• Hot-melt bonding agents are respectively applied to both of the faces of theintermediate sheet45 by hot-melt bonding-agent applying devices46 and47 so that theintermediate sheet45 is bonded to thebase sheet10 and the coveringsheets11 into an integral form between the base-sheet side receiving and transferring roller28(A) and the coating-sheet side receiving and transferring roller28(B); thus, a sheet-shaped water-absorbent body44 composed of a plurality of layers is manufactured.
• By using the above-mentioned manufacturing device, thebase sheet10, theintermediate sheet45 and the coveringsheet11 can be melt-bonded to one another, as long as either the base-sheet side receiving and transferring roller28(A) or the coating-sheet side receiving and transferring roller28(B) is prepared as a heat roller.
• In addition, by making the diameter of receiving and transferring rollers28 (A, B) larger than that of temporary receiving rollers27 (A, B), a space to which theintermediate sheet45 is directed is prepared. In this case, in order to shift therespective materials10,11 and45 at the same speed, it is necessary to rotate the receiving and transferring rollers28 (A, B) slower than the temporary receiving rollers27 (A, B).
• InFIG. 7(b) that is a cross-sectional view of the sheet-shaped water-absorbent body44 composed of a plurality of layers, when the highly water-absorbent resin particle layers12 are placed at virtually the same position in upward and downward directions, thebase sheet10, theintermediate sheet45 and the coveringsheet11 are melt-bonded to one another at one time to form a sealingportion44a; however, the present invention is not intended to be limited to this layout. Here,reference numeral46arepresents a hot-melt bonding-agent layer applied on one surface of theintermediate sheet45 by a hot-melt bonding-agent applying device46, and reference numeral47arepresents a hot-melt bonding-agent layer applied on the other surface of theintermediate sheet45 by a hot-melt bonding-agent applying device47.
• Theintermediate sheet45 is preferably formed by a liquid-permeable non-woven fabric material, and examples of the non-woven fabric material include: hydrophilic fibers (cotton, rayon, cellulose, etc.), fibers prepared by subjecting hydrophobic fibers (polyethylene, polypropylene, polyethylene terephthalate, nylon, polyamide, etc.) to a hydrophilic-property applying treatment by using a surfactant or the like, and mixed fibers of these fibers.
INDUSTRIAL APPLICABILITY
• In accordance with the manufacturing method of a sheet-shaped body of the present invention, it becomes possible to stably fix a powder particle layer such as a highly absorbent resin particle layer at a predetermined position. In addition to an absorbent body of a disposable absorbent article, this sheet-shaped body can be used for various applications by changing the kinds of the powder particles.

Claims (10)

1. A device for manufacturing a sheet-shaped body in which a powder particle layer is sandwiched between a base sheet to which a bonding agent is applied and a covering sheet so as to be bonded into an integral body, the device comprising:

a receiving and transferring roller that shifts the base sheet with the base sheet being held on the roller face thereof;

a temporary receiving roller that transfers the powder particle layer onto the base sheet, while shifting the powder particle layer, with the powder particle layer being held on the roller face thereof; and

a contact-bond fixing roller that bonds the base sheet, the powder particle layer and the covering sheet into an integral form, while shifting the covering sheet with the covering sheet being held on the roller face thereof.

2. The device for manufacturing the sheet-shaped body according toclaim 1, wherein

surface peripheral velocities of the receiving and transferring roller, the temporary receiving roller and the contact-bond fixing roller are set to the same speed, or the surface peripheral velocity of the temporary receiving roller is set to be slower.

3. The device for manufacturing the sheet-shaped body according toclaim 1, wherein

concave grooves which receive the powder particle layer and shift the powder particle layer being held thereon in a layer form are formed on the roller face of the temporary receiving roller.

4. The device for manufacturing the sheet-shaped body according toclaim 3, wherein

a guide member for holding the powder particle layer is installed in a manner so as to face the roller face of the temporary receiving roller.

5. The device for manufacturing the sheet-shaped body according toclaim 1, wherein

at least one of the contact-bond fixing roller and the receiving and transferring roller is a heat roller.

6. The device for manufacturing the sheet-shaped body according toclaim 1, wherein

a press contact roller which presses the covering sheet to be in contact with the base sheet on the receiving and transferring roller is installed before the contact-bond fixing roller.

7. The device for manufacturing the sheet-shaped body according toclaim 1, wherein

a protective plate member which prevents the powder particle layer from flowing is attached to the receiving and transferring roller.

8. The device for manufacturing the sheet-shaped body according toclaim 7, wherein

the distance between the roller face of the receiving and transferring roller and the protective plate member is set in a range from 0.5 to 5 mm.

9. The device for manufacturing the sheet-shaped body according toclaim 1, wherein

the powder particle layer is a highly water-absorbent resin particle layer.

10. A method for manufacturing a disposable absorbent article, wherein

the sheet-shaped body manufactured by the manufacturing method according toclaim 5 is sandwiched between a liquid-permeable top sheet and a liquid-impermeable back sheet to be bonded into an integral form so that the disposable absorbent article is produced.

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