JP2023174860A - Absorber and manufacturing device thereof - Google Patents

Abstract

To provide an absorber for use in an absorbent article such as a disposable diaper and a menstrual napkin.SOLUTION: An absorber is formed by laminating a first absorbent core 3 including a first water-absorbing polymer 3P and a second absorbent core 4 including a second water-absorbing polymer 4P. The second absorbent core 4 has a part in which an existence ratio of the second water-absorbing polymer 4P is lower than that of the periphery along the longitudinal direction, at least a part of the first water-absorbing polymer 3P is composed of a water-absorbing polymer of the same quality as that of the second water-absorbing polymer 4P, an average particle size of the first water-absorbing polymer 3P is smaller than that of the second water-absorbing polymer 4P, and the first water-absorbing polymer 3P contains a pulverized non-spherical water-absorbing polymer.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method and apparatus for manufacturing absorbent bodies for various absorbent articles such as disposable diapers and sanitary napkins. The present invention also relates to an absorbent body.

Various absorbent articles such as disposable diapers and sanitary napkins generally include an absorbent body capable of absorbing and retaining liquid. Absorbents generally include hydrophilic fibers such as pulp and particles of water-absorbing polymers. The manufacture of absorbent bodies made of these materials generally involves a step of dispersing particles of water-absorbing polymers. The process of dispersing water-absorbing polymer particles is roughly divided into continuous dispersion and intermittent dispersion. For example, Patent Document 1 describes a method for manufacturing a sheet-like absorbent body by intermittently dispersing water-absorbing polymer particles between two sheet materials. In this document, a part of the continuously dispersed particles is removed to the outside using an ejecting means, so that the particles are intermittently dispersed. The document states that the particles are ejected by a high pressure air stream from a high pressure air injection device. The particles discharged to the outside are collected and supplied again to the particle dispersion process.

International Publication No. 2014/104115 pamphlet

According to the technique described in Patent Document 1, the particles removed to the outside are recovered and resupplied using the removal means, so that the yield can be improved. However, when expelling the particles to the outside, an external force is applied to the particles, which may cause the particles to be crushed into fine particles. When the atomized particles are re-supplied, the re-supplied particles are removed again and external force is repeatedly applied, which further promotes the atomization of the particles and gradually reduces the average particle size. A decrease in particle size may lead to a decrease in absorption performance such as liquid retention and absorption capacity. Resupplying such particles whose absorption performance has deteriorated becomes a factor that hinders the stable production of absorbers having the desired absorption performance.

Furthermore, the technique described in Patent Document 1 performs intermittent dispersion while allowing particles to fall freely. Therefore, if a high-pressure air flow is used to remove particles, the high-pressure air flow may disturb the falling state of freely falling particles, which may interfere with the stable supply of particles.

Therefore, an object of the present invention is to reliably consume the excluded and recovered water-absorbing polymer particles in a method for producing an absorbent body, thereby suppressing the progress of atomization.

Another object of the present invention is to periodically and reliably remove continuously falling powder while stably continuously falling the powder in the process of manufacturing an article containing powder.

The present invention provides a first absorbent core obtained by performing a manufacturing process of a first absorbent core containing a first water-absorbing polymer and a manufacturing process of a second absorbent core containing a second water-absorbing polymer in parallel. and a second absorbent core, in which the manufacturing process of the first absorbent core includes a step of continuously supplying the first water-absorbing polymer, and the manufacturing process of the second absorbent core includes: The second water-absorbing polymer is intermittently supplied to the base sheet by continuously supplying the second water-absorbing polymer and periodically removing the continuously supplied second water-absorbing polymer during the supply; The present invention provides a method for manufacturing an absorbent body, in which the second water-absorbing polymer removed in the manufacturing process of the absorbent core is recovered and conveyed to the continuous supply process in the manufacturing process of the first absorbent core.

The present invention also provides an apparatus for manufacturing an absorbent body formed by laminating a first absorbent core containing a first water-absorbing polymer and a second absorbent core containing a second water-absorbing polymer,
a first water-absorbent polymer supply section that supplies the first water-absorbent polymer to the first absorbent core;
a second water-absorbent polymer supply section that supplies a second water-absorbent polymer to the second absorbent core;
a recovery means for recovering the periodically removed second water-absorbing polymer;
Re-supply means for conveying the second water-absorbing polymer collected by the collection means to the first water-absorbing polymer supply section;
The present invention provides an apparatus for manufacturing an absorbent body having the following.

Furthermore, the present invention provides an absorbent body in which a first absorbent core containing a first water-absorbing polymer and a second absorbent core containing a second water-absorbing polymer are laminated,
The second absorbent core has a region along the longitudinal direction in which the abundance ratio of the second water-absorbing polymer is lower than that in the surrounding area,
At least a portion of the first water-absorbing polymer is composed of a water-absorbing polymer of the same quality as the second water-absorbing polymer,
The average particle size of the first water-absorbing polymer is smaller than the average particle size of the second water-absorbing polymer to provide an absorbent body.

According to the present invention, the water-absorbing polymer particles excluded and recovered during the manufacturing process of the absorbent body are reliably consumed, so that the progress of atomization of the particles is effectively suppressed.
In particular, according to the present invention, in the manufacturing process of the absorber, the continuous falling powder can be stably performed while periodically and reliably removing the continuously falling powder.

FIG. 1 is a schematic perspective view of an example of an absorbent body manufactured by the manufacturing method of the present invention. FIG. 2 is a cross-sectional view schematically showing a cross section taken along line II in FIG. FIG. 3(a) is a diagram showing an example of the pattern of the joint between the core wrap sheet and the second core in the absorbent body of the present invention, and FIG. 3(b) is a diagram showing the second water absorbency of the second absorbent core. It is a figure explaining the positional relationship between the area where a polymer exists and the first absorbent core. FIG. 4 is an overall schematic diagram of a manufacturing apparatus that can be used to implement the manufacturing method of the present invention. FIG. 5 is a diagram illustrating a second water-absorbing polymer recovery process and a transport process to the first core manufacturing process. FIG. 6 is a diagram showing an example of the configuration of the dispersion means. FIG. 7 is a plan view schematically showing an example of an adhesive application pattern on a core wrap sheet. FIG. 8 is a plan view schematically showing the state immediately before two base material sheets are superimposed on each other below the dispersing means in the second core manufacturing section. FIG. 9 is a plan view schematically showing an example of a dispersion pattern in which the water-absorbing polymer is intermittently dispersed onto the base sheet in the second core manufacturing section. FIG. 10 is a diagram showing the relationship between polymer particle size and water retention amount under pressure. FIG. 11 is a schematic cross-sectional view showing a measuring device for measuring the amount of water retained under pressure of a polymer particle size. FIG. 12 is an overall schematic diagram (corresponding to FIG. 4) of another manufacturing apparatus that can be used to implement the manufacturing method of the present invention. FIG. 13 is a diagram (corresponding to FIG. 5) for explaining the recovery process of the second water-absorbing polymer and the transport process to the first core manufacturing process. FIG. 14 is a diagram (corresponding to FIG. 6) showing another configuration example of the dispersing means. FIG. 15(a) shows the test results of the non-spreading width of the second water-absorbing polymer when suction is on, and FIG. 15(b) shows the test results of the non-spreading width of the second water-absorbing polymer when suction is off. It is a figure showing a result. FIG. 16 is a block diagram illustrating a schematic configuration of a control system of the manufacturing apparatus. FIG. 17 is a diagram illustrating the configuration of the main parts of yet another manufacturing apparatus that can be used to implement the manufacturing method of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on preferred embodiments thereof with reference to the drawings. In addition, in the description of the following drawings, the same or similar parts are given the same or similar symbols. The drawings are basically schematic, and the ratio of each dimension may differ from the actual one.

FIGS. 1 and 2 show an absorbent body 1, which is an example of an absorbent body that is the object of manufacture in the manufacturing method of the present invention. FIG. 4 schematically shows a manufacturing method for the absorbent body 1, which is an example of the manufacturing method of the present invention, and a manufacturing apparatus 10, which is an embodiment of a manufacturing apparatus that can be used to carry out the manufacturing method. The absorbent body 1 is an absorbent article (not shown) having a longitudinal direction X corresponding to the front-back direction of the wearer and a lateral direction Y perpendicular thereto, and absorbs body fluids such as urine, feces, menstrual blood, and sweat. It is used for holding. The absorbent core 1 includes an absorbent core 2 containing a water-absorbing material, and a liquid-permeable core wrap sheet 5 that covers the outer surface of the absorbent core 2.

As shown in FIG. 1, the absorbent body 1 and the absorbent core 2 constituting it have a long shape in the vertical direction X, the longitudinal direction of both coincides with the vertical direction direction) coincides with the horizontal direction Y. Further, the longitudinal direction , also called "CD", which is an abbreviation for Cross Machine Direction).

The absorbent core 2 is in contact with a first absorbent core 3 made of at least a water-absorbing polymer and a fiber material, and a skin-facing surface 3a or a non-skin-facing surface 3b of the first absorbent core 3. The absorbent core 4 has a second absorbent core 4 that is thinner than the second absorbent core 4 . In this specification, the "skin-facing surface" refers to the absorbent body or its constituent members (for example, the first absorbent core 3, the second absorbent core 4) during use (when wearing an absorbent article in which the absorbent body is incorporated). The "non-skin facing surface" refers to the surface facing the user's skin, that is, the side relatively close to the user's skin. The side toward which it is directed, ie the side relatively far from the user's skin.

In this embodiment, as shown in FIGS. 1 and 2, the second absorbent core 4 is in contact with the non-skin facing surface 3b of the first absorbent core 3. In this embodiment, the first absorbent core 3 is arranged closer to the user's skin than the second absorbent core 4, and therefore the first absorbent core 3 is closer to the user's skin than the second absorbent core 4. First, the absorbent body 1 comes into contact with the body fluid to be absorbed.

In this embodiment, the core wrap sheet 5 is one sheet. The core wrap sheet 5 covers the entire skin-facing surface of the absorbent core 2 (the skin-facing surface 3a of the first absorbent core 3, the skin-facing surface 4a of the second absorbent core 4), and extends in the longitudinal direction X of the absorbent core 2. It extends outward in the lateral direction Y from both side edges along The entire non-skin facing surface 4b) is covered.
As shown in FIG. 2, in the center of the non-skin-facing surface of the absorbent core 2 in the horizontal direction Y, both side edges (tips of the extending portions) of the core wrap sheet 5 along the vertical direction X overlap each other. An overlapping portion is formed. As the core wrap sheet 5, a liquid-permeable sheet can be used, and examples thereof include paper, nonwoven fabric, and the like. The core wrap sheet 5 and the second absorbent core 4 are directly joined by the joining part 6 without interposing the first absorbent core 3.

The first absorbent core 3 is interposed between the core wrap sheet 5 and the second absorbent core 4. The first absorbent core 3 is shorter than the second absorbent core 4 in at least one of the length in the vertical direction X and the length in the horizontal direction Y, and the arrangement of the first absorbent core 3 in the second absorbent core 4 At the peripheral edge of the surface (in the illustrated embodiment, the skin-facing surface 4a), there is a portion where the first absorbent core 3 is not disposed and the second absorbent core 4 is exposed.
In this embodiment, as shown in FIG. 1, the first absorbent core 3 is shorter in both the length in the longitudinal direction X and the length in the lateral direction Y than the second absorbent core 4, and the first absorbent core The entire periphery (outline) of the second absorbent core 4 is located inward from the periphery (outline) of the second absorbent core 4 . Therefore, the peripheral edge part (the part where the first absorbent core 3 is not arranged) of the skin-facing surface 4a (the surface where the first absorbent core 3 is arranged) of the second absorbent core 4 is covered with the core wrap sheet 5, and the core wrap sheet 5 is in a state where it can be contacted.

As shown in FIG. 1, in the first absorbent core 3, the length (width) in the horizontal direction Y is not constant over the entire length in the vertical direction It is long and wide. Generally, in an absorbent article, the relatively wide longitudinal end of the first absorbent core 3 in the longitudinal direction X is located on the ventral side (front side) of the wearer of the absorbent article. It is arranged so that it is located at
As shown in FIG. 2, the first absorbent core 3 contains a water-absorbing polymer and a fiber material 3F. Water-absorbing fibers are preferred as the fiber material 3F. Examples of water-absorbing fibers include wood pulps such as softwood pulp and hardwood pulp, natural fibers such as non-wood pulps such as cotton pulp and hemp pulp; modified pulps such as cationized pulp and mercerized pulp (including cellulose fibers); ); hydrophilic synthetic fibers and the like, and one type of these can be used alone or two or more types can be used in combination. The first absorbent core 3 typically contains cellulose fibers as the fiber material 3F. The first absorbent core 3 contains, as water-absorbing polymers, a first water-absorbing polymer 3P and a recovered second water-absorbing polymer 4P, which will be described below.
As is clear from the manufacturing method described below, at least a portion of the first water-absorbing polymer 3P included in the first absorbent core 3 is composed of a water-absorbing polymer of the same quality as the second water-absorbing polymer.

In this embodiment, the first water-absorbing polymer 3P contained in the first absorbent core 3 is generally in the form of particles, but may be in the form of fibers. The shape of the particulate first water-absorbing polymer 3P is not particularly limited, and may be, for example, spherical, lump-like, bale-like, or irregularly shaped. The first water-absorbing polymer 3P is typically mainly composed of a polymer or copolymer of acrylic acid or an alkali metal salt of acrylic acid.

The first absorbent core 3 has a region along the longitudinal direction X where the abundance ratio of the first water-absorbing polymer 3P is lower than in the surrounding area. As shown in FIGS. 1 and 2, this region also includes a form in which the core forming material of the first absorbent core 3 is not present throughout the entire thickness direction of the first absorbent core 3. Therefore, in the following description, this portion will be referred to as a forming material non-existing portion 3N. In the illustrated form, the forming material-free portion 3N is symmetrical with respect to an imaginary straight line (not shown) that bisects the first absorbent core 3 (absorbent body 1) in the horizontal direction Y and extends in the vertical direction X. A pair of virtual straight lines are formed on both sides of the virtual straight line. The pair of material-free portions 3N each have an elongated shape in the vertical direction X (specifically, a rectangular shape) in plan view. The forming material-free portion 3N functions as a flow path for the body fluid to be absorbed by the absorber 1, promotes diffusion of the body fluid in the surface direction, and can contribute to effective utilization of the absorption performance of the absorber 1. .
In addition, the forming material-free portion 3N also functions as a deformation guiding portion (flexible shaft) when the first absorbent core 3 deforms by bending in response to external force such as body pressure, and serves as a deformation guiding portion (flexible shaft) to It is possible to reduce discomfort when wearing the absorbent article and improve the feeling and fit of the absorbent article.
Since the forming material-free portion 3N plays such a role, it is placed in a region of the first absorbent core 3 where body fluids tend to concentrate (easily receives body fluids first) and where it is susceptible to external forces such as body pressure. It is preferable that From this point of view, the forming material-free portion 3N is a region corresponding to the wearer's crotch region when wearing the absorbent article in which the absorbent core 1 is incorporated, specifically, at least in the longitudinal direction X of the first absorbent core 3. It is preferable to arrange it in the central part of.

The forming material non-existing portion 3N is formed by intentionally stacking the core forming material including the fiber material 3F and the first water-absorbing polymer 3P in the step of stacking the core forming material including the fiber material 3F and the first water-absorbing polymer 3P during manufacturing of the first absorbent core 3. This is a site formed by inhibition.
In this embodiment, as shown in FIG. 2, the core wrap sheet 5 and the second absorbent core 4 (more specifically, the base sheet 4S described later) are joined in the forming material non-existing portion 3N. With such a configuration, the shape retention of the first absorbent core 3 is improved, and the shape of the first absorbent core 3 is difficult to collapse before and after absorbing body fluids, so that the absorbent performance of the absorbent body 1 is further improved.

As shown in FIG. 2, the second absorbent core 4 includes two base sheets 4S facing each other and a second water absorbent polymer 4P interposed between the two base sheets 4S, The two base sheets 4S are bonded to each other with an adhesive. As will be described later, the adhesive used for the second absorbent core 4 is applied in a predetermined pattern to the opposing surfaces of the two base sheets 4S (the surfaces on which the second water-absorbing polymer 4P is arranged). There is. As the adhesive used for the second absorbent core 4, any adhesive used for bonding constituent members in absorbent articles can be used without particular limitation, and for example, a hot melt adhesive can be used.

The base sheet 4S may be any sheet-like material that can fix the second water-absorbing polymer 4P, and may be liquid-permeable or liquid-impermeable. Examples of the base sheet 4S include fibrous structures such as nonwoven fabrics, woven fabrics, knitted fabrics, and paper, as well as resin films, foams, and nets, and one of these may be used alone or two or more of these may be laminated. It can be used as
The base sheet 4S typically includes a nonwoven fabric. As the nonwoven fabric constituting the base sheet 4S, those made by various manufacturing methods can be used without particular limitation, such as air-through nonwoven fabric, heat roll nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, meltblown nonwoven fabric, and spunbond-meltblown-spun fabric. Examples include bonded (SMS) nonwoven fabrics. These nonwoven fabrics may be hydrophilic nonwoven fabrics made of fibers that have been subjected to hydrophilic treatment.
Further, the two base sheets 4S may be the same or different from each other. In the latter case, for example, of the two base sheets 4S, one that is relatively closer to the skin of the wearer of the absorbent article (in this embodiment, closer to the first absorbent core 3) has liquid permeability. , it is possible to adopt a form in which the material farthest from the wearer's skin (first absorbent core 3) has liquid impermeability. The basis weight of one base sheet 4S is preferably 5 g/m ² or more, more preferably 7 g/m ² or more, from the viewpoint of a balance between making the absorber thinner and having practically sufficient strength. Preferably it is 50 g/m ² or less, more preferably 40 g/m ² or less.
In the first absorbent core 3 and the second absorbent core 4, the distribution form of the first water absorbent polymer 3P and the second water absorbent polymer 4P is not particularly limited, and may be uniformly distributed throughout the core. Although the former may be unevenly distributed in a part of the area, the former is preferable from the viewpoint of improving various performances such as liquid absorbency and flexibility.

As shown in FIG. 3(a), the core wrap sheet 5 and the second absorbent core 4 are directly joined by the joint portion 6 without interposing the first absorbent core 3. In this embodiment, the first water-absorbing polymer 3P is of the same type as the second water-absorbing polymer 4P, but the average particle size of the first water-absorbing polymer 3P is the same as that of the second water-absorbing polymer 4P. Those with a smaller diameter than the particle size are used. In this specification, the average particle size of the water-absorbing polymer refers to the median diameter. The median diameter is measured, for example, by a laser diffraction type dry particle size distribution measuring device.
In this embodiment, the length L2 of the region where the second water-absorbing polymer 4P contained in the second absorbent core 4 exists is the length L2 of the region in which the second absorbent polymer 4P exists, as shown in FIG. 3(b). Larger than L1. Therefore, even if the small-diameter first water-absorbing polymer 3P separates from the first absorbent core 3, it is received by the second absorbent core 4, so it is possible to prevent the first water-absorbing polymer 3P from falling off from the absorbent core 2, which is preferable.
Furthermore, since the length L2 of the region where the second water-absorbing polymer 4P exists is larger than the length L1 of the first absorbent core 3 in the longitudinal direction 4 is preferable because it can be absorbed reliably.

The absorbent body 1 is used as an absorbent body of an absorbent article. The term "absorbent articles" here includes a wide range of articles used to absorb bodily fluids (urine, soft stool, menstrual blood, sweat, etc.) discharged from the human body, such as disposable diapers, sanitary napkins, and sanitary napkins. Includes shorts, incontinence pads, etc.
Absorbent articles typically include an absorbent body, a liquid-permeable top sheet disposed on a side closer to the wearer's skin than the absorbent body, and a side farther from the wearer's skin than the absorbent body. and a liquid-impermeable or impermeable back sheet disposed on the inside.

Next, a method for manufacturing an absorbent core according to the present invention will be described with reference to the drawings, taking the method for manufacturing the absorbent core 1 described above as an example.
FIG. 4 is an overall schematic diagram of a manufacturing apparatus 10, which is an embodiment of a manufacturing apparatus that can be used to carry out the method for manufacturing the absorbent body 1. The manufacturing apparatus 10 includes a first absorbent core manufacturing unit (hereinafter referred to as “first core manufacturing unit”) 20 that manufactures the first absorbent core 3, and a first absorbent core 3 manufactured by the first core manufacturing unit 20. A first conveyance section 30 receives and conveys the second absorbent core 4, a second absorbent core manufacturing section (hereinafter referred to as "second core manufacturing section") 40 that manufactures the second absorbent core 4, and a second core manufacturing section 40 that manufactures the second absorbent core 4. and a second conveying section 50 that receives and conveys the second absorbent core 4.
In addition, below, the conveyance direction (flow direction) of the core wrap sheet 5 (absorbent body 1) is MD1, the conveyance direction (flow direction) of the base sheet 4S (4S1, 4S2) is MD2, MD3, and the second absorbent core 4 The conveyance direction (flow direction) is also called MD4.

In the manufacturing method using the manufacturing apparatus 10, the manufacturing process of the first absorbent core containing the first water-absorbing polymer 3P is performed in the first core manufacturing section 20, and the manufacturing process of the second absorbent core containing the second water-absorbing polymer 4P is performed. The process is performed in the second core manufacturing section 40. In the manufacturing method in this embodiment, the manufacturing process of the first absorbent core and the manufacturing process of the second absorbent core are performed in parallel, and the first absorbent core 3 and second absorbent core 4 obtained thereby are laminated.

The first core manufacturing unit 20 includes a fiber stacking drum 21 in which a plurality of stacking recesses (not shown) are formed at predetermined intervals on an outer peripheral surface 21S, a core forming material (in this embodiment, a fiber material 3F and a first The fiber stacking drum 21 is provided with a duct 22 that continuously supplies the water-absorbing polymer 3P) to the outer circumferential surface of the fiber stacking drum 21 while being accompanied by an air flow.
The upstream end (not shown) of the air flowing through the duct 22 is connected to the introduction device 60, and the downstream end covers a part of the outer circumferential surface 21S of the fiber stacking drum 21.
The introduction device 60 defibrates a raw material sheet mainly composed of the fiber material 3F, and continuously supplies the fiber supply section 61 which supplies the fiber material 3F into the duct 22 and the first water-absorbing polymer 3P into the duct 22. A first water-absorbing polymer supply section 62 for carrying out the process is provided.

The fiber stacking drum 21 includes a cylindrical drum main body 210 made of a rigid metal body, and an outer peripheral member 211 that is arranged to overlap the outer peripheral part of the drum main body 210 and forms an outer peripheral surface 21S of the fiber stacking drum 21. It consists of
The outer peripheral member 211 is configured to receive power from a prime mover such as a motor and rotate in the direction of arrow R1 in FIG. 4 about a horizontal rotation axis, but the drum body 210 is fixed. It does not rotate. The inside of the drum body 210 is partitioned into a plurality of spaces A, B, and C in the circumferential direction. Further, a pressure reducing mechanism (not shown) is connected to the drum body 210 to reduce the pressure inside the drum body 210, and the spaces A to C can be maintained at negative pressure by driving the pressure reducing mechanism.

In the fiber stacking drum 21, a space A whose outer peripheral portion is covered with a duct 22 is a fiber stacking zone in which core forming material can be stacked by suction from the inside. When the outer circumferential member 211 is rotated in the direction of arrow R1 while maintaining the negative pressure in the space A, the accumulation recess (not shown) formed in the outer circumferential member 211 passes over the space A. Negative pressure in the space A acts on the bottom of the accumulation recess, and air is sucked through a large number of suction holes formed at the bottom. By suction through this suction hole, the core forming material that has been conveyed inside the duct 22 is guided to the accumulation recess and stacked on the bottom of the stack, and the first absorbent core 3 that is the stacked fiber is It is formed.
On the other hand, the space B of the stacking drum 21 is usually set to a weaker negative pressure than the space A or zero pressure (atmospheric pressure), and the space C is set to the transfer position of the stacked fibers in the stacking recess. Since the area includes the area before and after that, the pressure is set to zero or positive pressure. The accumulation recess has a shape corresponding to the shape to be given to the first absorbent core 3 to be manufactured. In this embodiment, as described above, since the first absorbent core 3, which is the object to be manufactured by the first core manufacturing section 20, has the forming material-free portion 3N, no forming material is present at the bottom of the accumulation recess. The portion corresponding to the existing portion 3N protrudes outward in the radial direction of the fiber stacking drum 21 compared to the peripheral portion, thereby preventing the core forming material from stacking in the portion.

The first absorbent core 3 formed in the accumulation recess is conveyed to the lower part of the fiber stacking drum 21 by the rotation of the outer peripheral member 211, and is released from the accumulation recess by air discharge from the air discharge device 23. Then, the process moves to the first transport section 30.

As shown in FIG. 5, the first water absorbent polymer supply section 62 includes a first supply tank 63 that continuously supplies the first water absorbent polymer 3P to the duct 22, and a first water absorbent polymer that supplies the first water absorbent polymer 3P to the first supply tank 63. A first storage tank 64 in which 3P is stored. The first supply tank 63 is a sealed container, communicates with a part of the duct 22, and is configured to be able to supply the first water-absorbing polymer 3P into the duct 22. The first supply tank 63 also functions as a relay tank that stores the second water absorbent polymer 4P that is recovered and transported to the manufacturing process of the first absorbent core.
The first water absorbent polymer 3P stored in the first storage tank 64 is supplied to the first supply tank 63 by a first water absorbent polymer supply means 65 such as a screw feeder.

Returning to FIG. 4, the first conveyance section 30 includes a conveyance means 31 capable of conveying the conveyed object while sucking the conveyed object on the conveyance surface, and the conveyance means 31 rotates in the direction of arrow R2 in FIG. The conveyor belt 32 includes a conveyor belt 32 having a shape, and a suction box 33 as a suction means installed in the orbit of the conveyor belt 32.
The conveyor belt 32 forms a conveyance surface for objects to be conveyed, and has air permeability. The conveyor belt 32 is made of, for example, a mesh belt having a large number of suction holes (not shown).
The suction box 33 is installed at a position facing the air discharge device 23 with the conveyor belt 32 in between, and is capable of sucking air blown out from the air discharge device 23.
The core wrap sheet 5 is previously supplied onto the conveyor belt 32 before the first absorbent core 3 is released from the stacking recess and placed on the conveyor belt 32. The first absorbent core 3 released from the stacking recess is conveyed to the second conveyance section 50 while being placed on the core wrap sheet 5 .
Further, the first conveyance section 30 includes a pressing roll 36 that presses the first absorbent core 3 placed on the core wrap sheet 5 toward the core wrap sheet 5 side. The first absorbent core 3 is compressed in the thickness direction by the press roll 36 before being supplied to the second conveyance section 50 (before the second absorbent core 4 is stacked).

In the manufacturing apparatus 10, the core wrap sheet 5 is continuously unwound from the original fabric 5R in which the long core wrap sheet 5 is wound into a roll, and is supplied onto the conveyor belt 32 of the first conveyance section 30. During the supply to the conveyor belt 32, adhesives 34A, 35A (Fig. 7 (see adhesive application process).
In the adhesive application step, before arranging the first absorbent cores 3 on the core wrap sheet 5 that is conveyed in one direction (before implementing the first core arrangement step), the first absorbent cores 3 on the core wrap sheet 5 are This is a step of applying adhesives 34A and 35A to the placement surface (upper surface) of the. Specifically, in the adhesive application step, as shown in FIG. The adhesive 34A is continuously applied, and the adhesive 35A is continuously applied by the application means 35 to the central portion 5A of the CD on the one surface.
In this embodiment, the application means 34 is arranged upstream of the MD 1 than the application means 35, and therefore the adhesive 34A is applied to the core wrap sheet 5 before the adhesive 35A is applied. The center portion 5A of the CD of the core wrap sheet 5 is a portion where the first absorbent core 3 manufactured in the first core manufacturing section 20 is arranged, and the side portions 5B, 5B are respectively on the first absorbent core 3 side. This is the part that is folded back and overlapped with the first absorbent core 3 (see FIG. 7).

In the adhesive application step of the present embodiment, the adhesives 34A and 35A are applied to the central portion 5A and both side portions 5B and 5B of the CD on the surface (top surface) on which the first absorbent core 3 of the core wrap sheet 5 is arranged. are different. Specifically, as shown in FIG. 7, the adhesive 34A is applied in a continuous line extending in MD1 (longitudinal direction of the core wrap sheet 5) in plan view on both sides 5B, 5B, and the adhesive 35A is applied in the center. In the portion 5A, it is applied in a spiral shape extending in MD1 in plan view.
On one side of the core wrap sheet 5 after the adhesives 34A and 35A have been applied, there are a plurality of coated areas of the adhesive 34A in the CD (in FIG. In the central portion 5A, a plurality of (five in FIG. 7) application parts of the adhesive 35A having a spiral shape in plan view are arranged in parallel on the CD. The part of the core wrap sheet 5 where the adhesive 34A is applied in a continuous line is a so-called "solidly coated" part, and the adhesive 34A is adhered to the entire area of the part.
On the other hand, in the part of the core wrap sheet 5 where the adhesive 35A is applied in a spiral manner, the adhesive 35A extends in MD1 in a spiral manner, and the adhesive 35A-adhered part and non-adhered part are CD1. exist alternately. Note that the application patterns of the adhesives 34A and 35A are not limited to those shown in the drawings, and can be set arbitrarily.

As shown in FIG. 4, the manufacturing process of the second absorbent core carried out in the second core manufacturing unit 40 involves applying an adhesive to one surface of the base sheet 4S, which is a long sheet conveyed in one direction. After that, while continuously supplying the second water-absorbing polymer 4P, the continuously supplied second water-absorbing polymer 4P is periodically removed during the supply, thereby intermittently applying the second water-absorbing polymer 4P to the base sheet 4S. It comprises a water-absorbing polymer dispersion step of supplying, scattering, and adhesion, and a step of superimposing another elongated base material sheet on one surface of the base material sheet 4S to obtain the elongated second absorbent core 4. ing. A water-absorbing polymer may also be sprinkled on this "another long base sheet".

To explain further, in the second core manufacturing unit 40, after applying adhesives 41A and 42A (see FIG. 8) to the two base sheets 4S constituting the second absorbent core 4 using application means 41 and 42, respectively, The second water-absorbing polymer 4P is sprayed on the adhesive-coated surface of at least one of both sheets by the dispersing means 43, and then both sheets 4S are stacked with their respective adhesive-coated surfaces on the inside, A long second absorbent core 4 is manufactured.
In addition, in FIG. 4, one of the two base sheets 4S (the base sheet in contact with the first absorbent core 3) is designated as 4S1, and the other is designated as 4S2. That is, the manufacturing process of the second absorbent core includes a process of intermittently supplying the second water absorbent polymer 4P between the base sheets 4S1 and 4S2, which are two long sheets that are continuously conveyed in the same direction. There is.

More specifically, in the second core manufacturing unit 40, the long base sheet 4S1 is continuously unwound from the original fabric 4R1 wound into a roll, and one of the base sheets 4S1 is rolled out. The adhesive 41A is applied to the surface (the surface facing the other base sheet 4S2) by the application means 41. In parallel with this, the base sheet 4S2 is continuously unwound from the original fabric 4R2 in which the long base sheet 4S2 is wound into a roll, and one side of the base sheet 4S2 (the other side is The adhesive 42A is applied by the application means 42 to the surface facing the material sheet 4S1).
In this embodiment, as shown in FIG. 8, the adhesive 41A applied to the base sheet 4S1 in contact with the first absorbent core 3 extends in the transport direction (longitudinal direction) MD2 of the base sheet 4S1 in plan view. The adhesive 42A applied in a spiral manner to the base sheet 4S2 on which the second water-absorbing polymer 4P is directly sprinkled is applied to almost the entire area of one side of the base sheet 4S2 (so-called solid coating). . On one surface of the base sheet 4S1 after the adhesive 41A has been applied, a plurality (eight in FIG. 8) of applied parts of the adhesive 41A having a spiral shape in a plan view are arranged side by side in the CD. Adhesive 41A is applied in a spiral over substantially the entire area. Note that the application patterns of the adhesives 41A and 42A are not limited to those shown in the drawings, and can be set arbitrarily.

As shown in FIGS. 4 and 6, the spraying means 43 is arranged at a position spaced upward from the base sheet 4S to which the second water-absorbing polymer 4P is to be sprayed. The second water-absorbing polymer 4P sprayed from the spraying means 43 falls due to its own weight and adheres to one surface of the base sheet 4S (4S2) being conveyed below the spraying means 43. In this embodiment, the second water-absorbing polymer 4P is sprayed on one of the base sheets 4S1 and 4S2, but the second water-absorbing polymer 4P may be sprayed on the base sheets 4S1 and 4S2. .
The scattering means 43 is not particularly limited in its configuration as long as it can accurately scatter a predetermined amount of particles of the second water-absorbing polymer 4P at a predetermined position on the base sheet 4S being conveyed. For example, in the present embodiment, as shown in FIGS. 5 and 6, the dispersion means 43 is capable of storing the second water absorbent polymer 4P in the form of powder inside, and has an outlet 431a for discharging the second water absorbent polymer 4P. and a conveying means 432 located below the hopper 431 and conveying the second water-absorbing polymer 4P discharged from the discharge port 431a to a spraying position and dispersing it.
The conveying means 432 includes a receiving means 433 for receiving the second water-absorbing polymer 4P discharged from the discharge port 431a, and a vibration generating means 434 for vibrating the receiving means 433. The vibration generating means 434 vibrates the receiving means 433. By doing so, the second water-absorbing polymer 4P on the receiving means 433 can be transported to the spraying position.

In this embodiment, as shown in FIG. 5, the hopper 431 is provided with a second water-absorbing polymer supply section 162 that supplies the second water-absorbing polymer 4P. The second water absorbent polymer supply section 162 includes a second supply tank 163 that continuously supplies the second water absorbent polymer 4P to the hopper 431, and a second supply tank 163 that continuously supplies the second water absorbent polymer 4P to the hopper 431, and a second supply tank 163 that continuously supplies the second water absorbent polymer 4P to the second supply tank 163. It includes a storage tank 164 and a second water-absorbing polymer supply means 165 that supplies the second water-absorbing polymer 4P in the second storage tank 164 to the second supply tank 163.
The second supply tank 163 is a sealed container, and the bottom thereof and the hopper 431 are communicated through a conveyance path 166. The second water-absorbing polymer 4P in the second supply tank 163 is supplied to the hopper 431 via the conveyance path 166.
An adjustment valve 169 is disposed in the conveyance path 166 as an adjustment means for adjusting the amount of second water-absorbing polymer 4P supplied to the hopper 431 by adjusting the cross-sectional area within the path. As the regulating valve 169, either a butterfly valve that opens and closes the valve body by manual operation or a solenoid valve that opens and closes the valve body by electronic control may be used, but in this embodiment, a solenoid valve is used.
The second water-absorbing polymer supply means 165 includes a vacuum transfer device 167 provided in the second supply tank 163 and a supply path 168 connecting the vacuum transfer device 167 and the second storage tank 164. The supply path 168 has one end connected to the suction side of the vacuum transfer device 167 and the other end connected to the second storage tank 164. The second water absorbent polymer 4P stored in the second storage tank 164 is an unused second water absorbent polymer 4P.
According to the second water-absorbing polymer supply means 165, when the vacuum transfer device 167 is activated, the unused second water-absorbing polymer 4P in the second supply tank 163 is transferred to the second supply tank 163 along with the gas flow. is supplied via the transport path 166, and is stirred and mixed with the existing second water-absorbing polymer 4P in the second supply tank 163.

In the second core manufacturing section 40, as shown in FIG. 4, the elongated second absorbent core 4 obtained through the step of dispersing the second water absorbent polymer 4P by the dispersing means 43 is introduced between the nip rolls 44 and 45. After compressing in the thickness direction, an adhesive is applied to one surface of the second absorbent core 4 (the surface facing the first absorbent core 3) by the application means 46.
In this embodiment, the adhesive is applied in a spiral shape extending in the transport direction (longitudinal direction) MD4 of the second absorbent core 4 in plan view. On one surface of the second absorbent core 4 after the adhesive has been applied, a plurality (for example, five) of adhesive application parts having a spiral shape in plan view are arranged in a CD. Note that the adhesive application pattern is not limited to the above-mentioned pattern, and can be arbitrarily set. The elongated second absorbent core 4 having one surface coated with the adhesive in this manner is conveyed to the second conveyance section 50 and superimposed on the first absorbent core 3 .

In this embodiment, in the water-absorbing polymer dispersion step performed in the second core manufacturing unit 40, as shown in FIG. The second water-absorbing polymer 4P is intermittently sprinkled so as to be disposed intermittently in the transport direction MD3 of the base sheet 4S2. Due to the intermittent dispersion of the second water-absorbing polymer 4P, the adhesion area 4M and non-adhesion area 4N of the second water-absorbing polymer 4P are formed on one surface of the base sheet 4S2 in the transport direction MD3 (of the base sheet 4S2). arranged alternately in the longitudinal direction).
The reason why the second water-absorbing polymer 4P is intermittently sprinkled on the base sheet 4S (4S2) is to smoothly cut the second absorbent core 4 (absorbent body 1) after this spraying step. It's for a reason. That is, the steps after obtaining the long second absorbent core 4 are as follows: 1) The long second absorbent core 4 is transported as it is to the second transport section 50, and the core wrap sheet 5 is folded by a folding means 56, which will be described later. A process of obtaining a long absorbent body 1 through the folding process and cutting the long absorbent body 1 into a predetermined product unit length; After the core 4 has passed between the nip rolls 44 and 45 and after the adhesive has been applied, the long second absorbent core 4 is cut into a predetermined product unit length to obtain a single sheet of the second absorbent core 4. However, since water-absorbing polymers are generally very hard, the second absorbent core 4 (absorbent core 4) in 1) or 2) above may be included. If the second water-absorbing polymer 4P is present at the cutting position of the body 1), poor cutting may occur.

In this embodiment, in order to prevent defective cutting of the second absorbent core 4 (absorbent core 1), the second water-absorbing polymer 4P is not sprayed at the position where the long second absorbent core 4 is to be cut. I have to. That is, when cutting the elongated second absorbent core 4 in 1) or 2) above, the cutting is performed at the non-adhering region 4N of the second water-absorbing polymer 4P. Therefore, the second absorbent core 4 obtained by cutting the elongated second absorbent core 4 has a portion in the longitudinal direction where the abundance ratio of the second water absorbent polymer is lower than the surrounding area. The region is located at the front and rear end regions of the second absorbent core in the longitudinal direction. In addition, in this embodiment, as shown in FIG. 4, the long second absorbent core 4 is conveyed as it is to the second conveyance section 50 without being cut, and the above-mentioned 1) is adopted.

In the method of intermittently spraying the second water absorbent polymer 4P onto the base sheet 4S, the second water absorbent polymer 4P is continuously sprayed from the spray means 43, and the second water absorbent polymer 4P is sprayed continuously from the spray means 43 onto the base sheet 4S. A method is adopted in which the flow of the second water-absorbing polymer 4P toward 4S is appropriately blocked.

In this intermittently spraying step, in this embodiment, in the second water-absorbing polymer dispersing step in the second core manufacturing unit 40, the second water-absorbing polymer 4P is placed at a position apart from the base sheet 4S (4S2). The second water-absorbing polymer 4P that continuously falls from the dispersing means 43 toward the base sheet 4S (4S2) is periodically removed, and the second water-absorbing polymer 4P is intermittently sprinkled.
In this embodiment, as shown in FIGS. 4 and 6, the second core manufacturing unit 40 has a second water-absorbing polymer between the dispersing means 43 and the base sheet 4S (4S2) conveyed below the dispersing means 43. It is equipped with a 4P recovery means 47.
The recovery means 47 recovers the second water absorbent polymer 4P that was periodically removed and was not supplied between the base sheets 4S (4S2) in the second absorbent core manufacturing process, and It is transported to the continuous supply process in. The recovery of the second water-absorbing polymer 4P and the process of conveying it to the continuous supply process in the manufacturing process of the first absorbent core will be described later. Note that the second water-absorbing polymer that is recovered and transported to the manufacturing process of the first absorbent core is hereinafter referred to as "recovered second water-absorbing polymer 4P1."

The second transport unit 50 includes a transport means 51 that can transport the object on the transport surface while sucking it. The conveying means 51 of the second conveying section 50 includes a breathable conveyor belt 52 that moves along a predetermined orbit in the direction of arrow R3 in FIG. 4, a suction box 53 as a suction means installed in the orbit, 54. The conveyor belt 52 forms a conveyance surface for an object to be conveyed, and the object to be conveyed (a laminate of the core wrap sheet 5, the first absorbent core 3, and the second absorbent core 4) is placed on the upper surface of the conveyor belt 52. The conveyor belt 52 is made of, for example, a mesh belt having a large number of suction holes (not shown). When the suction boxes 53 and 54 are operated, the objects to be conveyed on the conveyor belt 52 (conveyance surface) are sucked through suction holes (not shown).

Further, as shown in FIG. 4, the second conveyance section 50 transports the first absorbent core 3 and the second absorbent core 4 manufactured by the second core manufacturing section 40 onto the first absorbent core 3. A press roll 55 is provided that presses the laminate of the two absorbent cores 4 from the second absorbent core 4 side (upper surface side). The press roll 55 is located on the opposite side of the suction box 53 across the core wrap sheet 5 (first absorbent core 3) being transported at or near the confluence point of the second absorbent core 4 on the transport path of the core wrap sheet 5. It is located in

Further, as shown in FIG. 4, the second conveyance unit 50 includes a folding means 56 for the core wrap sheet 5 on the downstream side of the MD from the press roll 55. The folding means 56 is installed in a part of the orbit of the conveyor belt 52, and is arranged corresponding to the installation location of the suction box 54. The folding means 56 is configured to fold back the absorbent core 2 (a laminate of the first absorbent core 3 and the second absorbent core 4) placed on both sides 5B, 5B of the core wrap sheet 5 during conveyance, that is, the core wrap sheet 5. A known folding mechanism is provided for folding back the extending portions from both side edges along the MD toward the absorbent core 2 side.

The plurality of first absorbent cores 3 manufactured in the first core manufacturing section 20 are transported to the center of the upper surface of the elongated core wrap sheet 5 being conveyed in one direction (direction indicated by code MD1) by the first conveying section 30. 5A and intermittently placed in MD1. Adhesives 34A and 35A are applied in advance to substantially the entire upper surface of the core wrap sheet 5 by application means 34 and 35, and the arranged first absorbent core 3 is adhered to the upper surface of the core wrap sheet 5. .
The core wrap sheet 5 to which the first absorbent core 3 is adhered is pressed toward the core wrap sheet 5 side by the press roll 36 included in the first conveying section 30, thereby compressing the first absorbent core 3 in the thickness direction. It is transported to the second transport section 50.
The core wrap sheet 5 including the first absorbent core 3 transported to the second transport section 50 is overlapped with the second absorbent core 4 to which an adhesive has been applied in advance by the application means 46 at the confluence position P1, and the core wrap The sheet 5 and the second absorbent core 4 are joined and integrated.

In the second conveyance section 50, after the long second absorbent core 4 is joined onto the first absorbent core 3 disposed in the central part 5A of the CD of the long core wrap sheet 5, the core is The long absorbent body 1 is folded back toward the center portion 5A side (second absorbent core 4 side) so that both side portions 5B, 5B of the CD of the wrap sheet 5 are wrapped (rolled up) around the second absorbent core 4. get.
The elongated absorbent body 1 obtained as described above is then cut into a predetermined product unit length by a cutting means (not shown), and the absorbent body 1 as shown in FIG. 1 is manufactured. As described above, the non-adhesive area 4N of the second water absorbent polymer 4P exists at the planned cutting position in the long absorbent body 1 due to the intermittent spraying of the second water absorbent polymer 4P constituting the second absorbent core 4. By cutting the long absorbent body 1 in the non-adhesion region 4N, cutting defects are less likely to occur, and the work of cutting into product unit lengths can be smoothly performed.

The recovery process of the second water absorbent polymer 4P and the process of conveying it to the continuous supply process in the first absorbent core manufacturing process will be described.
As shown in FIGS. 5 and 6, the collection means 47 includes a collection box 472 equipped with an opening 471 through which the second water-absorbing polymer 4P, which is powder continuously falling from the dispersion means 43, passes; A shutter 473 is provided as a closing means that closes periodically.
In addition to the collection means, the manufacturing apparatus 10 also transports and supplies the second water-absorbing polymer 4P accumulated in the collection box 472 to the first supply tank 63 in the manufacturing process of the first absorbent core. A supply means 474 is provided.
The collection box 472 has a hollow shape and is arranged in a range including the position where the second water-absorbing polymer 4P continuously falls from the dispersing means 43. An opening 471 is formed in the bottom 472a of the collection box 472 at a position where the second water-absorbing polymer 4P falls continuously. A duct 477 is arranged above the opening 471 and serves as a guide path for guiding the second water-absorbing polymer 4P continuously falling from the dispersing means 43 into the collection box 472. The continuously falling second water-absorbing polymer 4P is introduced into the collection box 472 via the duct 477, passes through the opening 471, and is combined with the base sheet 4S1, which becomes a long sheet located below the opening 471. The material is continuously supplied between the material sheets 4S2.

The shutter 473 is arranged inside the collection box 472. The shutter 473 is configured to be slidable between a position where the opening 471 is opened and a position where the opening 471 is closed. During normal times, the shutter 473 occupies a position where the opening 471 is opened, and when the timing for blocking the opening 471 comes, it is moved by a drive means (not shown) to close the opening 471. The timing of blocking the opening 471 is the timing of forming the non-adhesion region 4N (see FIG. 9) of the second water-absorbing polymer 4P on one surface of the base sheet 4S2. When the timing for blocking the opening 471 has passed, the shutter 473 is returned to the position where the opening 471 is opened by the driving means, and is held at that position until the next timing for blocking the opening 471. .
The collection box 472 is arranged so as to be inclined with respect to the falling direction of the second water-absorbing polymer 4P. In this embodiment, in FIG. 6, the right end 472b, which is one end, is located below the left end 472c, which is the other end. The end portion 472b constitutes a deposition portion. Therefore, when the opening 471 is closed by the shutter 473, the second water-absorbing polymer 4P, which has been prevented from falling from the opening 471 by the shutter 473, is received on and around the shutter 473, and the second water-absorbing polymer 4P is caught on and around the shutter 473, and the second water-absorbing polymer 4P is stopped by the shutter 473 from falling through the opening 471. It slides to the side and accumulates. The end portion 472b is formed to be tapered toward the inclination direction, so that the second water-absorbing polymer 4P that slides down the bottom portion 472a and accumulates on the end portion 472b is easily collected in the tapered portion.

By the way, if the second water-absorbing polymer 4P collected and accumulated in the collection box 472 is re-supplied to the second supply tank 163, it will fall from the hopper 431 and be used for manufacturing the second water-absorbing polymer 4P. Therefore, the yield of the second water-absorbing polymer 4P becomes good. However, when the particles of the second water-absorbing polymer 4P are expelled to the outside, an external force is applied to the particles, which may cause the particles to be crushed into fine particles. For example, when the shutter 473 is used to cut off the supply of the second water-absorbing polymer 4P between the base sheets as in this embodiment, the continuously falling second water-absorbing polymer 4P and the shutter 473 that opens and closes. Due to the collision, the second water-absorbing polymer 4P tends to be crushed and become fine particles. For example, when the second water-absorbing polymer 4P is spherical, the spherical second water-absorbing polymer 4P is crushed into a non-spherical shape.
When the atomized second water-absorbing polymer 4P is re-supplied to the hopper 431, the chance of collision with the shutter 473 increases, atomization is promoted, and the average particle size gradually becomes smaller. A decrease in the particle size of the second water-absorbing polymer 4P may lead to a decrease in absorption performance such as body fluid retention ability. Resupplying such particles whose absorption performance has deteriorated becomes a factor that hinders the stable production of absorbers having the desired absorption performance.

FIG. 10 is a diagram showing the measurement results of the relationship between the particle size of polymer particles and the water retention amount under pressure (hereinafter referred to as "water retention amount under pressure"). In FIG. 10, the horizontal axis indicates the particle size, and the vertical axis indicates the water retention amount under pressure. For the measurement, water-absorbing polymers 22P having average particle diameters of 100 μm, 300 μm, and 500 μm were produced, and the amount of water retained under pressure was measured using the measuring device shown in FIG. 11.
With reference to FIG. 11, a measuring device for carrying out a method of measuring the amount of water retained under pressure will be described.
As shown in FIG. 11(1), a column 210A is prepared in which a mesh 213 (250 mesh) is pasted on the lower end opening 212 of a vertically erected cylinder 211A (inner diameter 30 mm). 0.500 g of water-absorbing polymer 22P (particles) is placed therein so as to have a uniform thickness. Next, a weight 221 (a weight capable of applying a pressure of 2.0 kPa) having an outer diameter slightly smaller than 30 mm is placed on the water absorbent polymer 22P.
Pour 100 mL of physiological saline 231 (0.9 mass% sodium chloride aqueous solution) at room temperature (20±5° C.) into a 100 mL beaker 230. Then, the column 210A is immersed in physiological saline 231 without the mesh 213 touching the bottom of the beaker 230, and left in this state for one hour.
Thereafter, the column 210A is taken out from the beaker 230 and drained for 15 minutes with a weight 221 placed on the water-absorbing polymer 22P, as shown in FIG. 11(2). The temperature of this test atmosphere is room temperature (20±5° C.).
Then, the water retention amount under pressure is calculated according to the following equation (1).

According to FIG. 10, the tendency of the measurement results is that as the particle size of the water-absorbing polymer becomes smaller (fine), the amount of water retained under pressure decreases, which may cause a decrease in the absorption performance of the absorbent body.

Therefore, in this embodiment, the second water-absorbing polymer 4P collected and deposited in the collection box 472 is transferred not to the second absorbent core manufacturing process (second supply tank 163) but to the first water-absorbing polymer manufacturing process. (first supply tank 63) is collected and transported by resupply means 474.
As shown in FIG. 5, the resupply means 474 includes a vacuum transfer device 475 provided in the first supply tank 63 and a recovery path 476 that connects the vacuum transfer device 475 and the recovery box 472. One end 476a of the recovery path 476 is connected to the suction side of the vacuum transfer device 475, and the other end 476b is connected to the end 472b of the recovery box 472.
In such a resupply means 474, when the vacuum conveyance device 475 is operated, the second water absorbent polymer 4P deposited in the collection box 472 is collected together with the gas flow and transferred to the first supply tank as the recovered second water absorbent polymer 4P1. 63. As a result, in the first supply tank 63, the first water-absorbing polymer 3P and the recovered second water-absorbing polymer 4P1 are stirred and mixed by the air flow.
That is, in the manufacturing process of the first absorbent core, the first water absorbent polymer 3P is supplied from the first storage tank 64 to the first supply tank 63, and is collected and transported from the manufacturing process of the second absorbent core. The recovered second water-absorbing polymer 4P1 is supplied, whereby a mixture of the first water-absorbing polymer 3P and the recovered second water-absorbing polymer 4P1 is continuously supplied from the first supply tank 63 to the duct 22.

As described above, according to the manufacturing method of the present embodiment, the second water-absorbing polymer 4P, which has been used in the second manufacturing process and is recovered and is likely to become atomized, is not returned to the second manufacturing process. First, it is returned to the first manufacturing process as a recovered second water-absorbing polymer 4P1, mixed with the first water-absorbing polymer 3P, and used for manufacturing the first water-absorbing polymer 3P.
Therefore, the particles of the second water-absorbing polymer 4P that are excluded and recovered in the manufacturing process of the absorbent body 1 (the manufacturing process of the second absorbent core 4) are reliably consumed, so that the particles of the water-absorbing polymer are not atomized. The progress can be effectively suppressed, and the yield of the second water-absorbing polymer 4P can also be reduced. Further, since the progress of atomization of the water-absorbing polymer particles can be suppressed, an absorbent body having the desired absorption performance can be stably produced.

According to the manufacturing method of this embodiment, in the manufacturing process of the second absorbent core, the second water-absorbing polymer 4P is intermittently supplied between the base sheets 4S1 and 4S2, which are two long sheets that are continuously conveyed. Since the method includes a step, a non-adhering region 4N of the second water-absorbing polymer 4P is formed in the transport direction CD of the base sheet. Therefore, the second absorbent core 4 (absorbent body 1) can be cut in the non-adhesion region 4N, so that poor cutting can be prevented.

According to the manufacturing method of this embodiment, the recovered second water absorbent polymer 4P1 recovered and transported from the manufacturing process of the second absorbent core is transferred to the first water absorbent polymer 3P from the first storage tank 64. It is supplied to the first supply tank 63, mixed with the first water absorbent polymer 3P, and continuously supplied from the first supply tank 63 to the manufacturing process of the first absorbent core. Therefore, the first water-absorbing polymer 3P and the recovered second water-absorbing polymer 4P1 are well mixed in the first absorbent core 3, so that deterioration in the performance of the first absorbent core 3 can be suppressed. Therefore, it is possible to stably produce an absorbent body having the desired absorption performance.
When the second water-absorbing polymer 4P is spherical, the water-absorbing polymer supplied to the first supply tank 63 is a mixture of the first water-absorbing polymer 3P and the pulverized non-spherical second water-absorbing polymer 4P. Become. Therefore, the first absorbent core 3 includes a first water-absorbing polymer 3P and a crushed non-spherical second water-absorbing polymer 4P. In other words, the first water absorbent polymer 3P in the first absorbent core 3 contains a pulverized non-spherical water absorbent polymer.

With respect to the amount of the first water-absorbing polymer 3P supplied from the first storage tank 64 to the first supply tank 63, the recovered second water-absorbing polymer 3P is transported from the manufacturing process of the second absorbent core and supplied to the first supply tank 63. If the ratio of the water-absorbing polymer 4P1 is too large, the water-absorbing performance of the first absorbent core 3 may be lower than that of the first water-absorbing polymer 3P alone due to the influence of the fine powder contained in the recovered second water-absorbing polymer 4P1. There is sex.
Therefore, the amount of the recovered second water-absorbing polymer 4P1 relative to the amount of the first water-absorbing polymer 3P supplied to the first supply tank 63 is determined by considering the absorption performance, particle size, etc. of the recovered second water-absorbing polymer 4P1. , 1/3 or less, preferably 1/5 or less, more preferably 1/6 or less.
In this way, by specifying the amount of the recovered second water absorbent polymer 4P1 to be supplied to the first supply tank 63 to be at least ⅓ or less, the influence of the fine powder contained in the recovered second water absorbent polymer 4P1 is suppressed, A decrease in the water absorption performance of the first absorbent core 3 can be suppressed.

Adjustment of the ratio of the recovered second water-absorbing polymer 4P1 supplied to the first supply tank 63 and the first water-absorbing polymer 3P in the first supply tank 63 is performed when the recovered second water-absorbing polymer 4P1 is supplied to the first supply tank 63 from the first storage tank 64. This can be realized by adjusting the supply amount of the first water-absorbing polymer 3P and the supply amount of the recovered second water-absorbing polymer 4P1 transported from the recovery box 472 by the re-supply means 474. For example, when the supply amount of the first water-absorbing polymer 3P supplied from the first storage tank 64 to the first supply tank 63 is a fixed supply, the re-supply means The value of the conveyance amount of the recovered second water-absorbing polymer 4P1 by 474 can be adjusted.

In this embodiment, from the viewpoint that the first water absorbent polymer 3P and the second water absorbent polymer 4P are mixed in the first supply tank 63 and used for manufacturing the first absorbent core 3, the first water absorbent polymer 3P and the second water-absorbing polymer 4P are made of the same kind of substance. Specifically, as the second water-absorbing polymer 4P, a water-absorbing polymer of the same type as the first water-absorbing polymer 3P is used.
By using the first water-absorbing polymer 3P and the second water-absorbing polymer 4P that are made of the same kind of material in this way, it is possible to suppress a decrease in the performance of the first absorbent core 3. Therefore, it is possible to more stably manufacture an absorbent body having the desired absorption performance.

According to the manufacturing method of this embodiment, when the second water-absorbing polymer is continuously dropped and intermittently dropped from the opening 471, the shutter 473 is used to periodically close the opening 471 during the fall. , the second water-absorbing polymer 4P can be reliably removed. Therefore, the non-adhesion region 4N of the second water-absorbing polymer 4P can be more reliably formed in the transport direction CD of the base sheet, and cutting defects can be more reliably prevented.

According to the manufacturing method of the present embodiment, the recovered second water absorbent polymer 4P1 recovered in the second absorbent core manufacturing process is conveyed to the continuous supply process in the first absorbent core manufacturing process while accompanied by a gas flow. Therefore, the external force applied to the water-absorbing polymer is small compared to a conveyance method that applies mechanical force such as a screw conveyor, which prevents the recovered second water-absorbent polymer 4P1 from becoming atomized during conveyance, and improves the performance of the first absorbent core 3. The decrease can be suppressed. Therefore, it is possible to more stably manufacture an absorbent body having the desired absorption performance.

In the present embodiment, in the manufacturing process of the first absorbent core, the first water absorbent polymer 3P and the second water absorbent polymer (recovered second water absorbent polymer 4P1) are both mixed with the fiber material 3F to form the first absorbent core. Used for manufacturing core 3. Therefore, in the manufacturing process of the first absorbent core, the first water absorbent polymer 3P and the second water absorbent polymer (recovered second water absorbent polymer 4P1) are not removed. As a result, the fine powder contained in the second water-absorbing polymer is reliably consumed without being removed or recovered, suppressing further atomization and producing an absorbent body with the desired absorption performance more stably. be able to.

Next, another embodiment of the present invention will be described with reference to FIGS. 12 to 14.
As shown in FIGS. 12 to 14, in the manufacturing apparatus 10, the recovery means 47 for the second water-absorbing polymer 4P includes an accumulation section 48.

The storage section 48 is for collecting and storing the second water-absorbing polymer 4P deposited in the collection box 472. As shown in FIGS. 13 and 14, the accumulation section 48 includes an accumulation tank 481 and a recovery path 482 configured with piping that connects the accumulation tank 481 and the recovery box 472. The storage tank 481 has a volume that can sufficiently store the second water-absorbing polymer 4P stored in the collection box 472.
One end 482a of a recovery path 482 is connected to an upper end 481a of the storage tank 481 so as to communicate with the inside of the storage tank 481 via a seal member. The other end 482b of the collection path 482 is connected to the end 472b where the second water-absorbing polymer 4P is deposited inside the collection box 472 via a seal member so as to communicate with the inside of the collection box 472.

A switching valve 483 is installed at the bottom 481b of the storage tank 481 as a valve that can selectively select the transport path of the second water-absorbing polymer 4P stored in the storage tank 481. As the switching valve 483, a butterfly valve whose valve body is opened and closed by manual operation, or a solenoid valve whose valve body is opened and closed by electronic control can be used. In this embodiment, a solenoid valve is used.
The switching valve 483 is operated when selecting whether to subject the second water-absorbing polymer 4P stored in the storage tank 481 to the transport process or to discharge it outside the storage tank 481. For this reason, a three-way valve is used as the switching valve 483. The switching valve 483 has one port on the introduction side and two ports on the discharge side. A discharge path 484 connected to a discharge container (not shown) is connected to one discharge side port of the switching valve 483, and a recovery path 476 is connected to the other discharge side port. The position of the switching valve 483 is set so as to guide the second water-absorbing polymer 4P in the storage tank 481 to the re-supply path 491 during normal times.

The storage tank 481 includes a sensor that detects the storage state of the second water-absorbing polymer 4P in the tank. The sensors include a sensor 111 (upper sensor) installed at the upper part 481c of the storage tank 481, a sensor 113 installed near the top of the storage tank 481, and a sensor (lower sensor) installed at the lower part 481d of the recovery tank. It is 112. The vicinity of the top here refers to the range from the upper end 481a of the storage tank 481 to the collection box 472. More specifically, it extends from the upper end 481a to the collection box 472, and includes the collection path 482. In this embodiment, the sensor 113 is installed at the upper end 481a of the storage tank 481.
The sensor 111 detects whether the second water-absorbing polymer 4P in the storage tank 481 has reached the planned storage amount. The sensor 113 detects whether the second water-absorbing polymer 4P in the storage tank 481 has reached its storage limit. The sensor 112 is for detecting whether the storage amount of the second water-absorbing polymer 4P in the storage tank 481 has reached the minimum storage amount.
Further, a sensor 115 is installed in the transport path from the collection box 472 to the storage section 48. Specifically, in this embodiment, it is arranged on the collection path 482 located between the end 472b of the collection box 472 and the on-off valve 496. The sensor 115 detects whether or not the second water-absorbing polymer 4P in the recovery channel 482 is clogged. As the sensor 115, a capacitance sensor or a paddle-type sensor that is provided with a detection paddle in the recovery path 482 and detects the degree of passage of the second water-absorbing polymer 4P from the amount of rotation of the paddle can be used. .

As the sensors 111 to 113, light transmission type optical sensors are used. For this reason, each sensor includes a light emitting section and a light receiving section, and at least the light emitting surface and the light receiving surface are disposed within the storage tank 481. Each sensor is configured to output detection light emitted from a light emitting part by receiving it at a light receiving part, and is of a type in which the output changes when the second water-absorbing polymer 4P is detected and when it is not detected. It is. The sensors 111 to 113 are not optical sensors, but are capacitance sensors or paddle-type sensors that provide a detection paddle in the recovery path 482 and detect the degree of passage of the second water-absorbing polymer 4P from the amount of rotation of the paddle. Sensors can be used.

As shown in FIG. 14, a sensor 114 is installed near the opening 471 of the collection means 47. The sensor 114 detects whether the second water-absorbing polymer 4P is passing through the opening 471 properly. The vicinity of the opening 471 is a range in which the amount of the second water-absorbing polymer 4P passing through the opening 471 can be detected. It is installed so that it faces towards the

In this embodiment, since the second water-absorbing polymer 4P is collected by the storage section 48, the second water-absorbing polymer 4P deposited in the collection box 472 is introduced into the storage tank 481 through the collection path 482. stored. Therefore, the removed second water-absorbing polymer 4P does not overflow from the collection box 472. As a result, the second water-absorbing polymer 4P accumulated in the collection box 472 is prevented from leaking from the opening 471 and falling. As a result, uneven distribution of the second water-absorbing polymer 4P can be prevented.

In this embodiment, as shown in FIGS. 12 and 13, the second water-absorbing polymer 4P stored in the storage tank 481 is transported to the first supply tank 63 by the resupply means 474. As shown in FIG. 13, the resupply means 474 includes a vacuum transfer device 475 provided in the first supply tank 63 and a recovery path 476 connecting the vacuum transfer device 475 and the storage tank 481. One end 476a of the recovery path 476 is connected to the suction side of the vacuum transfer device 475, and the other end 476b is communicatively connected to the bottom 481b of the storage tank 481 (see FIG. 14) via a switching valve 483. To explain in more detail, the other end 476b of the recovery path 476 is connected to the other outlet of the switching valve 483, and is configured to transport the second water-absorbing polymer 4P using airflow and positive pressure. It is composed of

By the way, when the second water-absorbing polymer 4P collected and stored in the storage tank 481 is conveyed along with the gas flow using the re-supply means 474, the second water-absorbing polymer 4P freely falls from the dispersion means 43. This may cause a phenomenon in which the falling state of the product is disturbed. Such a phenomenon may hinder the stable supply of the second water-absorbing polymer 4P to the area to be sprayed. Such a phenomenon may become a factor in the variation in the second water-absorbing polymer 4P sprinkled on the base sheet 4S, and may also affect the formation of the non-adhesion region 4N.

Therefore, in this embodiment, the removal of the second water-absorbing polymer 4P and the recovery of the second water-absorbing polymer 4P are spatially separated. As for when to shut off, it was determined when the second water-absorbing polymer 4P was transported to the above-described continuous supply process. This is because the suction of the air flow generated during the continuous supply process and the effects of the pulsation associated with it act on the collection box 472 through the storage tank 481, and the second water-absorbing polymer 4P freely falls toward the opening 471. This is because it is presumed to have an influence.
For this reason, the manufacturing apparatus 10 in this embodiment includes an on-off valve 496 as an isolating means for spatially separating the removal of the second water-absorbing polymer 4P from the recovery of the second water-absorbing polymer 4P. The on-off valve 496 is disposed between the shutter 473 that removes the second water-absorbing polymer 4P and the storage section 48 that collects the removed second water-absorbing polymer 4P. Specifically, an on-off valve 496 is installed in a recovery path 482 that is disposed between and connected to the recovery box 472 and the storage section 48, so that the recovery path 482 can be opened and closed. The on-off valve 496 opens the recovery path 482 during normal times, allowing the second water-absorbing polymer 4P discharged from the recovery box 472 to be introduced into the recovery path 482. On the other hand, when the vacuum conveyance device 475 of the resupply means 474 is operated to convey the second water-absorbing polymer 4P, the on-off valve 496 is closed.

According to this embodiment, even when the vacuum conveyance device 475 is operated and the recovered second water absorbent polymer 4P1 is conveyed by the resupply means 474, the recovery path 482 is closed by the on-off valve 496. Therefore, the collection box 472 and the storage tank 481 of the storage section 48 are spatially isolated, so that they are less susceptible to the suction effect or pulsation of the air flow generated on the resupply means 474 side. As a result, in the manufacturing process of the absorbent body 1 containing the second water-absorbing polymer 4P, the continuously falling second water-absorbing polymer 4P is periodically and reliably removed, and the continuous falling of the second water-absorbing polymer 4P is prevented. It can be done stably. This leads to the ability to form the non-adhesion region 4N well.

FIG. 15 shows the falling second water-absorbing polymer when the vacuum conveying device 475 is activated and suction force is generated (suction always on) and when it is not activated and suction force is not generated (suction always off). It is a figure which shows the test result of inspecting the non-dispersion width of 4P. FIG. 9(a) shows the measurement results when the suction is always on, and FIG. 9(b) shows the test results when the suction is always off. In both figures, the vertical axis shows the non-dispersion width, and the horizontal axis shows the number of inspections.
As for the inspection method, a method was adopted in which the second absorbent core 4 was imaged using an image inspection machine and the non-dispersion width of the second absorbent core 4 was measured from the captured image. Note that the non-dispersion width of the second absorbent core 4 may be inspected using a capacitance sensor instead of an image inspection machine.

When the highest value (MAX), lowest value (MIN), average value (Ave.), and standard deviation of the non-dispersion width were calculated and compared from the test results in FIGS. 15(a) and 15(b), the highest value The difference in standard deviation (3σ) was more remarkable than the difference in (MAX), minimum value (MIN), and average value (Ave.). Specifically, when the suction is always on, the standard deviation (3σ) is 20.2 mm, but when the suction is always off, the standard deviation (3σ) is 9.6 mm, which is better when the suction is always off. The result was that the variation in non-dispersion width became smaller.
From this result, in the manufacturing process of the absorber 1, the resupply means 474 (vacuum conveying device 475) is turned on/off to spatially control the removal of the second water absorbent polymer 4P and the recovery of the second water absorbent polymer 4P. It can be confirmed that by isolating the second water-absorbing polymer 4P, the continuous fall of the second water-absorbing polymer 4P can be performed stably, and the non-adhesion region 4N can be formed well.

Next, the configuration and control contents of the control system of the manufacturing apparatus 10 in this embodiment will be explained.
FIG. 16 is a block diagram illustrating a schematic configuration of the control system of the manufacturing apparatus 10. As shown in FIG. 16, the manufacturing apparatus 10 includes a control means 100. The control means 100 includes a CPU 101 which is a central processing unit, a RAM 102 and a ROM 103 which are storage units, and a timer 104 which is a measurement means. Although not shown, the control means 100 includes interfaces on the input side and output side to which means and devices to be controlled and sensors as detection means can be connected via signal lines. The input side interface includes sensors 111, 112, 113 installed in the storage tank 481, a sensor 114 installed near the opening 471 of the collection box 472, and a sensor between the collection box 472 and the storage section 48. Sensors 115 installed on a recovery path 482, which is a transport path, are connected via signal lines, and detection results (outputs) from each sensor are transmitted to the control means 100.
At the output side interface, a signal line is connected to a dispersing means 43, a warning display section, a regulating valve 169, a vacuum conveying device 167 and a vacuum conveying device 475, a drive motor for opening and closing the shutter 473, a switching valve 483, and an on-off valve 496. connected via. Although not shown in the figure, drive units other than those described above, such as the first core manufacturing unit 20, first transport unit 30, second core manufacturing unit 40, and second transport unit 50, are connected to the output side interface. The start and stop of operation can be controlled by commands from the control means 100. Start of operation is a state in which the drive system of the manufacturing apparatus 10 is operated to manufacture the absorbent body 1 by the manufacturing apparatus 10, and stoppage of operation is a state in which the drive system of the manufacturing apparatus 10 is operated to manufacture the absorbent body 1. It refers to stopping.

Each control mode will be explained below, but in each control mode it is assumed that the manufacturing apparatus 10 is already in an operating state (control mode 1).
In control form 1, control is performed based on the time measured by the timer 104 without using sensors. In control mode 1, the conveyance process is started every time the measurement time t measured by the timer 104 reaches a set time t1 preset in the ROM 102, and the second water-absorbing polymer 4P is removed and the second water-absorbing polymer 4P is removed. 4P recovery is spatially separated. Specifically, when the measured time t≧the set time t1, a signal is sent from the control means 100 to the on-off valve 496 to control its closing, and at the same time, the vacuum transfer device 475 is activated.

In this way, when the set time t1 comes, the vacuum transfer device 475 is activated and the on-off valve 496 is controlled to close, so that the collection box 472 and the storage tank 481 of the storage section 48 are spaced apart every set time t1. Since the re-supplying means 474 side is isolated from the rest, it is less susceptible to the suction effect and pulsation of the air flow generated on the re-supply means 474 side. As a result, in the manufacturing process of the absorbent body 1 containing the second water-absorbing polymer 4P, the continuously falling second water-absorbing polymer 4P is periodically and reliably removed, and the continuous falling of the second water-absorbing polymer 4P is stabilized. Go to target. This leads to the ability to form the non-adhesion region 4N well. Further, since the on-off valve 496 is automatically closed by the control means 100, there is no separation of space, and the second water-absorbing polymer 4P can be continuously dropped more stably.

(Control form 2)
In control mode 2, a sensor detects the amount of second water-absorbing polymer 4P stored in an accumulation tank 481 equipped with a sensor. By detecting the storage amount of the second water-absorbing polymer 4P in the storage tank 481 with a sensor, it is possible to accurately know the storage amount in the storage tank 481, and to perform control commensurate with the storage amount. .

(Control form 3)
In control mode 3, the sensor 111 installed on the upper part 481c of the storage tank 481 detects whether the second water-absorbing polymer 4P in the storage tank 481 has reached the planned storage amount. In this control mode, when the sensor 111 installed on the upper part 481c of the storage tank 481 detects the second water-absorbing polymer 4P, the control means 100 determines that the planned storage amount has been stored. Since the output of the sensor 111 changes when it detects the second water-absorbing polymer 4P, the control means 100 (CPU 101) determines that the planned storage amount has been reached when there is a change in the output from the sensor 111.
In control mode 3, when it is detected that the second water-absorbing polymer 4P in the storage tank 481 has reached the planned storage amount, the vacuum is turned on to start conveying the second water-absorbing polymer 4P to the first supply tank 63. While operating the transport device 475, the on-off valve 496 is controlled to close in order to spatially isolate the collection box 472 and the storage tank 481 of the storage section 48.
Therefore, when the second water-absorbing polymer 4P in the storage tank 481 reaches the planned storage amount, the second water-absorbing polymer 4P in the storage tank 481 is transported to the first supply tank 63 as a recovered second water-absorbing polymer 4P1. The second water-absorbing polymer 4P can be stably dropped continuously even though it is reused.
In this control mode, when it is detected that the second water-absorbing polymer 4P in the storage tank 481 has reached the scheduled storage amount, the vacuum transfer device 475 is activated at that point, and the on-off valve 496 is controlled to close. However, it is not necessary to perform the control immediately after detection, and the control may be performed after a certain period of time has elapsed (delay control). In this case, a certain period of time is stored in the ROM 103 in advance, and the timer 104 starts measurement from the time when the sensor 111 detects that the scheduled storage amount has been reached, and after the certain period of time has elapsed, the vacuum transfer device 475 is activated. It is sufficient to operate the on-off valve 496 and close the on-off valve 496 at the same time. In this way, by introducing delay control, it is possible to eliminate transient outputs of the sensor 111 and variations in the outputs of the sensors, thereby improving control accuracy.

(Control form 4)
In control mode 4, the sensor 113 installed near the top of the storage tank 481 detects whether the second water-absorbing polymer 4P in the storage tank 481 has reached its storage limit. In this control mode, when the sensor 113 installed near the top detects the second water-absorbing polymer 4P, the control means 100 determines that the water has been stored up to the storage limit. The control means 100 (CPU 101) determines that the storage limit amount has been reached based on the change in the output when the sensor 113 detects the second water-absorbing polymer 4P.
In this control mode, when the second water-absorbing polymer 4P in the storage tank 481 reaches the storage limit, the control means 100 stops the operation of all drive systems in order to stop the operation of the manufacturing apparatus 10 at that point. Stop.
Therefore, the second water-absorbing polymer 4P recovered from the storage tank 481 can be prevented from overflowing to the recovery path 482 side, which is outside the tank.
In this control mode, a warning display section may be activated to display and warn that the storage tank 481 is at its storage limit before and after the operation of the drive system of the manufacturing apparatus 10 is stopped. .

(Control form 5)
In control mode 5, the sensor 112 installed at the lower part 481d of the storage tank 481 detects whether the storage amount of the second water-absorbing polymer 4P in the storage tank 481 has reached the minimum storage amount. The control means 100 continues the normal operating state to collect the second water-absorbing polymer 4P transported from the collection box 472 in the storage tank 481 until the storage amount of the second water-absorbing polymer 4P reaches the minimum storage amount. do. Then, when it is detected from the sensor 112 that the storage amount has reached the minimum storage amount, the control means 100 controls the vacuum transfer to stop the transfer of the second water-absorbing polymer 4P to the first supply tank 63 at that point. The operation of the device 475 is stopped, and the on-off valve 496 is controlled to close, thereby spatially separating the collection box 472 and the storage tank 481 of the storage section 48.
In this way, since the operation of the vacuum transfer device 475 is stopped to avoid idle operation of the vacuum transfer device 475, damage to the vacuum transfer device 475 can be prevented.

(Control form 6)
In control mode 6, a switching valve 483 provided at the bottom 481b of the storage tank 481 is used to selectively select the destination of the second water-absorbing polymer 4P in the storage tank 481. As described above, the switching valve 483 configured as a three-way valve has a valve body positioned so as to transport the second water-absorbing polymer 4P to the first supply tank 63.
For example, when the sensor 113 detects that the storage amount in the storage tank 481 has reached the storage limit, the control means 100 sends a signal to the switching valve 483 to change the position of the valve body connected to the discharge container. By switching to the discharge path 484 side, the second water-absorbing polymer 4P in the storage tank 481 can be discharged to the outside of the tank, so there is no need to stop the operation of the manufacturing device 10, and a decrease in productivity is suppressed. It will be done.
Alternatively, when cleaning the inside of the storage tank 481 is assumed, the control means 100 is provided with a cleaning mode and a switch for activating the mode, and when the switch is operated and the cleaning mode is set, the position of the valve body is changed to the discharge container. The storage tank 481 can be emptied by controlling the switch to the discharge path 484 side connected to the storage tank 481.

(Control form 7)
In control mode 7, the sensor 114 installed near the opening 471 formed in the collection box 472 detects the appropriateness of passage of the second water-absorbing polymer 4P. When the second water-absorbing polymer 4P has properly passed through the opening 471, the control means 100 controls the transport of the second water-absorbing polymer 4P in the storage tank 481 to the first supply tank 63. If it is detected that the second water-absorbing polymer 4P has not passed through the opening 471 properly, the second water-absorbing polymer 4P is controlled to stop falling at that point. Specifically, the operation of a drive motor (not shown) is controlled to move the shutter 473, which opens and closes to the closed position, to intermittently supply the second water-absorbing polymer 4P.
To determine whether or not the second water-absorbing polymer 4P is passing through the opening 471 properly, the output from the sensor 114 at the time of proper passage is set in the ROM 103 in advance, and the output from the sensor 114 is compared with the set value. It can be detected by doing so. The output from the sensor 114 at the time of proper passage is not a single value, but a permissible range is set, and if the output from the sensor 114 exceeds the permissible range, it can be determined that the passage is not proper. This is preferable because oversensitive control can be avoided.

(Control form 8)
Control mode 8 is such that the presence or absence of clogging of the second water-absorbing polymer 4P in the recovery path 482 can be detected by the sensor 115 installed in the recovery path 482 that communicates the recovery box 472 and the storage section 48. .
To determine whether or not the second water-absorbing polymer 4P is clogged in the recovery channel 482, the output from the sensor 115 during normal, non-clogged conditions is set in the ROM 103 in advance, and the output from the sensor 115 and the set value are compared. It can be detected by If this sensor 115 detects a blockage in the recovery path 482, the blockage in the recovery path 482 may be due to a defect in the on-off valve 496 installed downstream of the sensor 115 in the transport direction, or a defect in any of the sensors 111 to 113. It is assumed that the second water-absorbing polymer 4P is clogged. Therefore, when the sensor 115 detects clogging in the recovery path 482, it is preferable that the control means 100 control the manufacturing apparatus 10 to stop operating.

In control mode 3-5, by performing the delay control described in control mode 2, it is possible to eliminate variations in each transient output and sensor output, thereby increasing control accuracy.

Although the manufacturing apparatus 10 described in each of the above embodiments is assumed to be newly installed, the concept of the present invention can also be applied to existing manufacturing apparatuses. An example is shown in FIG. The manufacturing apparatus 10A shown in FIG. 17 uses the same type of water-absorbing polymer supplied to the first supply tank 63 and the second supply tank 163, and the second storage tank 164 described in the manufacturing apparatus 10 is used as a shared storage tank 164A. It is used as The vacuum transfer device 475 and the vacuum transfer device 167 are connected to transfer paths 203 and 204 through which the water-absorbing polymer is transferred from the storage tank 164A via the path switching valve 201.
Further, the storage tank 481 described in the manufacturing apparatus 10 is connected to the other end 476Ab of the recovery path 476A that communicates the transport path 204 and the storage tank 481, thereby forming a resupply means 474A. A switching valve 207 for switching the transport route is provided at the connection between the transport route 204 and one end 476Aa of the recovery route 476A. The switching valve 207 has a path that guides the second water-absorbing polymer 4P recovered in the storage tank 481 from the recovery path 476A to a first transport path 204A that transports it to the vacuum transport device 475, and a path that guides the second water-absorbing polymer 4P recovered in the storage tank 481. It is possible to switch between the recovery path 476A and the second transport path 204B, which transports the liquid to the storage tank 164A.

Also in the manufacturing apparatus 10A having such a configuration, by switching the switching valve 207 to the first conveyance path 204A side, the recovered second water absorbent polymer 4P is transferred to the first supply tank 63 as the recovered second water absorbent polymer 4P1. Since it can be transported, the recovered second water-absorbing polymer 4P1 can be recycled. In addition, by switching the switching valve 207 to the second transporting route 204B while switching the route switching valve 201 so that the transporting route 204 and the vacuum transporting device 167 communicate with each other, the recovered second water-absorbing polymer 4P can be transferred. Since the recovered second water-absorbing polymer 4P1 can be transported to the vacuum conveying device 167, the recovered second water-absorbing polymer 4P1 can be recycled. In this case, by closing the on-off valve 496 when transporting the recovered second water-absorbing polymer 4P1, the recovery path 482 is closed by the on-off valve 496, so that the recovery box 472 and the accumulation tank 481 of the accumulation section 48 can be spatially separated. As a result, the same effects as those described in the embodiments described above are achieved.

Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit of the present invention.
For example, the first absorbent core 3 does not need to have the forming material absent portion 3N, and even if the first absorbent core 3 has the forming material absent portion 3N, the number may vary depending on the embodiment. It is not limited to the number of
In the embodiment described above, the first absorbent core 3 was a fiber stack containing the fiber material 3F, the first water absorbent polymer 3P, and the second water absorbent polymer (recovered second water absorbent polymer 4P1). Like the core 4, it may be made of a water-absorbing polymer. Even in this case, the second water-absorbing polymer 4P that is intermittently supplied by the opening and closing operation of the shutter 473, that is, the second water-absorbing polymer 4P that is prevented from falling by the shutter 473 and pulverized into atomized particles, is By resupplying the recovered second water-absorbing polymer 4P1 to the manufacturing process of the first absorbent core, the same effects as in the embodiment described above can be achieved.
If the particle size of the first water-absorbing polymer 3P used in the first absorbent core 3 is smaller than the particle size of the second water-absorbing polymer 4P, the particle size of the recovered second water-absorbing polymer 4P1 and the first water-absorbing polymer 3P By making the particle sizes of the two particles close to each other, it is possible to suppress the difference in performance due to the difference in particle size between the two. As a result, it can be expected that deterioration in the performance of the first absorbent core 3 can be suppressed, which is preferable because it leads to more stable production of an absorbent body having the desired absorption performance.

Further, in the embodiment, vacuum conveyance using positive pressure is used as a driving source for the resupply means 474 that conveys the second water absorbent polymer 4P from the accumulation section 48 to the first supply tank 63 as the recovered second water absorbent polymer 4P1. Although the device 475 was used, the drive source for the resupply means 474 may be of a type that sucks and conveys the second water-absorbing polymer 4P from the storage tank 481 using negative pressure.

Furthermore, in the embodiment, the second water absorbent polymer 4P stored in the storage tank 481 is transported to the first absorbent core manufacturing process (first supply tank 63) as the recovered second water absorbent polymer 4P1. However, the method for recycling the second water-absorbing polymer 4P is not limited to this method. For example, depending on the degree of atomization by pulverization of the second water-absorbing polymer 4P, the second water-absorbing polymer 4P may not be returned to the second supply tank 63 instead of being returned to the first absorption core manufacturing process (first supply tank 63). 163 and may be reused in the manufacturing process of the second absorbent core. Even in this case, the second water-absorbing polymer 4P removed by the shutter 473 can be recycled, which is preferable.

Regarding the embodiment of the present invention described above, the following method for manufacturing an absorbent body is further disclosed.

<1>
The manufacturing process of the first absorbent core containing the first water-absorbing polymer and the manufacturing process of the second absorbent core containing the second water-absorbing polymer are performed in parallel, and the first absorbent core and the second absorbent core obtained thereby are A method of manufacturing an absorbent body by laminating a core and a core,
The manufacturing process of the first absorbent core includes a continuous supplying process of the first water absorbent polymer,
In the manufacturing process of the second absorbent core, while continuously supplying the second water absorbent polymer, the continuously supplied second water absorbent polymer is periodically removed during the supply, thereby converting the second water absorbent polymer into a base sheet. Including the process of intermittent supply,
A method for manufacturing an absorbent body, comprising collecting the second water-absorbing polymer removed in the second absorbent core manufacturing process and transporting it to the continuous supply step in the first absorbent core manufacturing process.

<2>
The manufacturing method according to <1>, wherein the manufacturing process of the second absorbent core includes a process of intermittently supplying the second water-absorbing polymer between two long sheets that are continuously conveyed in the same direction.
<3>
In the first absorbent core manufacturing process, the first water absorbent polymer is supplied from the first storage tank to the first supply tank, and the second water absorbent polymer is recovered and transported from the second absorbent core manufacturing process. The manufacturing method according to <1> or <2>, wherein the mixture of the first water-absorbing polymer and the second water-absorbing polymer is continuously supplied from the first supply tank.
<4>
In the manufacturing process of the first absorbent core,
The production according to <3>, wherein the first water-absorbing polymer and the second water-absorbing polymer recovered in the manufacturing process of the second absorbent core are mixed by being stirred by an air flow in the first supply tank. Method.
<5>
The amount of the second water absorbent polymer recovered in the manufacturing process of the second absorbent core and supplied to the first supply tank is 1/3 of the amount of the first water absorbent polymer supplied to the first supply tank. The manufacturing method according to <4> above, which is as follows.
<6>
In the manufacturing process of the first absorbent core,
The manufacturing method according to any one of <1> to <5> above, wherein a raw material sheet mainly composed of a fibrous material is defibrated and the fibrous material is supplied into a duct.

<7>
The manufacturing process of the second absorbent core includes a step of continuously dropping the second water absorbent polymer to pass through the opening,
By periodically closing the opening with a closing means, the continuously falling second water-absorbing polymer is periodically prevented from passing through the opening, and the second water-absorbing polymer is caused to fall intermittently. The manufacturing method according to any one of <1> to <6> above, wherein the second water-absorbing polymer that is blocked from passing through the opening is also removed.
<8>
In the manufacturing process of the second absorbent core,
The manufacturing method according to <7>, wherein the second water-absorbing polymer whose falling from the opening is prevented by the closing means slides to the depositing part and is deposited.
<9>
Any of the above <1> to <8>, wherein the second water-absorbing polymer recovered in the second absorbent core manufacturing process is conveyed to the continuous supply process in the first absorbent core manufacturing process, accompanied by a gas flow. The manufacturing method described in (1) above.
<10>
comprising a conveying means located below a hopper capable of storing the second water-absorbing polymer and conveying the second water-absorbing polymer discharged from the outlet of the hopper to a spraying position and spraying;
The conveying means has a receiving means for receiving the second water-absorbing polymer discharged from the discharge port, and a vibration generating means for vibrating the receiving means,
In the manufacturing process of the second absorbent core,
The manufacturing method according to any one of <1> to <9>, wherein the second water-absorbing polymer on the receiving means is transported to a spraying position by vibrating the receiving means with the vibration generating means.
<11>
The manufacturing method according to any one of <1> to <10>, wherein the first water-absorbing polymer and the second water-absorbing polymer are made of the same kind of substance.

<12>
The manufacturing method according to any one of <1> to <11>, wherein in the manufacturing process of the first absorbent core, neither the first nor the second water-absorbing polymer is removed.
<13>
Any of the above <1> to <12>, which spatially separates the removal of the second water-absorbing polymer from the recovery of the second water-absorbing polymer when the second water-absorbing polymer is conveyed to the continuous supply step. The manufacturing method described in (1) above.
<14>
The manufacturing method according to <13> above, wherein in recovering the second water-absorbing polymer, the removed second water-absorbing polymer is stored in an accumulation tank.
<15>
Every time the measurement time measured by the measuring means reaches a preset time, the second water-absorbing polymer is started to be transported to the continuous supply step, and the second water-absorbing polymer is removed and the second water-absorbing polymer is removed. The manufacturing method according to <13> or <14>, wherein the polymer recovery is spatially separated.
<16>
In recovering the second water-absorbing polymer, the removed second water-absorbing polymer is stored in an accumulation tank equipped with a sensor;
The manufacturing method according to any one of <13> to <15>, wherein the storage amount of the second water-absorbing polymer in the storage tank is detected by the sensor.

<17>
the sensor is installed at the top of the storage tank;
Detecting whether the second water-absorbing polymer in the storage tank has reached a predetermined storage amount by the sensor;
When it is detected that the storage amount of the second water-absorbing polymer has reached the scheduled storage amount, the transportation of the second water-absorbing polymer to the continuous supply step is started at that point, or after a certain period of time has elapsed, and The manufacturing method according to <16> above, wherein the removal of the second water-absorbing polymer and the recovery of the second water-absorbing polymer are spatially separated.
<18>
the sensor is installed near the top of the storage tank;
Detecting by the sensor whether the second water-absorbing polymer in the storage tank has reached a storage limit;
The manufacturing method according to <16> or <17>, wherein when it is detected that the storage amount of the second water-absorbing polymer has reached the storage limit, the operation is stopped at that point or after a certain period of time has elapsed. .
<19>
the sensor is installed at the bottom of the storage tank;
While transporting the second water-absorbing polymer in the storage tank, detecting with the sensor whether the storage amount of the second water-absorbing polymer in the storage tank has reached a minimum storage amount;
When it is detected that the storage amount of the second water-absorbing polymer has reached the minimum storage amount, at that point, the transportation of the second water-absorbing polymer to the continuous supply step is stopped, or after a certain period of time has elapsed, and The manufacturing method according to any one of <16> to <18>, wherein the removal of the second water-absorbing polymer and the recovery of the second water-absorbing polymer are spatially communicated.
<20>
A valve is provided at the bottom of the storage tank to selectively select a transport route for the second water-absorbing polymer stored in the storage tank,
Any of <16> to <19> above, wherein the second water-absorbing polymer stored in the storage tank is subjected to the continuous supply step or to the discharge step out of the storage tank by switching the valve. The manufacturing method described in (1) above.
<21>
In removing the second water-absorbing polymer, a sensor is installed near the opening,
detecting whether the second water-absorbing polymer is properly passing through the opening by a sensor;
If it is detected that the second water-absorbing polymer is not passing through the opening properly, the falling of the second water-absorbing polymer is stopped at that point or after a certain period of time has elapsed. 20>.

<22>
<13> to <21> above, wherein the presence or absence of clogging of the second water-absorbing polymer in the transport path is detected by a sensor installed in the transport path from removal of the second water-absorbing polymer to recovery of the second water-absorbing polymer. The manufacturing method according to any one of the above.
<23>
An apparatus for producing an absorbent body formed by laminating a first absorbent core containing a first water-absorbing polymer and a second absorbent core containing a second water-absorbing polymer,
a first water-absorbent polymer supply section that supplies the first water-absorbent polymer to the first absorbent core;
a second water-absorbent polymer supply section that supplies a second water-absorbent polymer to the second absorbent core;
a recovery means for recovering the periodically removed second water-absorbing polymer;
Re-supply means for conveying the second water-absorbing polymer collected by the collection means to the first water-absorbing polymer supply section;
An apparatus for producing an absorbent body.
<24>
The resupply means includes a recovery path connecting a first supply tank provided in the first water-absorbing polymer supply section and a recovery box provided in the recovery means, and a vacuum provided in the first supply tank. The manufacturing device according to <23> above, comprising a conveyance device.
<25>
The manufacturing apparatus according to <24>, wherein a sensor is installed in the recovery path.
<26>
According to any one of <23> to <25>, wherein the resupply means is configured to convey the second water-absorbing polymer to the first water-absorbing polymer supply section along with the gas flow. manufacturing equipment.

<27>
the second absorbent core includes a second water absorbent polymer and a base sheet,
The manufacturing apparatus according to any one of <23> to <26>, further comprising the collecting means between the second water-absorbing polymer dispersing means and the base sheet conveyed below.
<28>
The collection means spatially isolates a collection box in which the second water-absorbing polymer is deposited, an accumulation section that collects and accumulates the second water-absorbing polymer deposited in the collection box, and the collection box and the accumulation section. The manufacturing apparatus according to any one of <23> to <27>, further comprising an on-off valve.
<29>
The manufacturing apparatus according to <28>, wherein the collection box includes an opening through which the continuously falling second water-absorbing polymer passes, and a closing means for periodically closing the opening.
<30>
The manufacturing apparatus according to <29> above, wherein a sensor is installed near the opening.
<31>
The manufacturing apparatus according to any one of <28> to <30>, wherein the collection box has a hollow shape and is arranged in a range including a falling position of the continuously falling second water-absorbing polymer.

<32>
The manufacturing apparatus according to any one of <28> to <31>, wherein the collection box is arranged to be inclined with respect to the falling direction of the second water-absorbing polymer.
<33>
The manufacturing device according to <32>, wherein the lower end of the collection box is tapered toward the inclination direction.
<34>
The manufacturing device according to any one of <28> to <33>, wherein the accumulation section includes an accumulation tank, and the accumulation tank and the recovery box are connected by a recovery path.
<35>
The manufacturing apparatus according to any one of <28> to <34>, wherein the sensor is installed between the collection box and the on-off valve.
<36>
Any one of <28> to <35> above, wherein a switching valve is installed at the bottom of the storage tank to selectively select a transport route for the second water-absorbing polymer stored in the storage tank. The manufacturing equipment described in .

<37>
The manufacturing apparatus according to any one of <28> to <36>, wherein the storage tank includes a sensor that detects the storage state of the second water-absorbing polymer in the storage tank.
<38>
The manufacturing apparatus according to <37>, wherein the storage tank has the sensor at an upper part of the storage tank.
<39>
The manufacturing apparatus according to <37>, wherein the storage tank has the sensor at the top of the storage tank.
<40>
The manufacturing apparatus according to <37>, wherein the storage tank has the sensor at a lower part of the storage tank.
<41>
According to any one of <28> to <40>, the second water absorbent polymer stored in the storage tank is configured to be transported to the first water absorbent polymer supply section by the resupply means. manufacturing equipment.
<42>
The manufacturing apparatus according to any one of <23> to <41>, further comprising a control means including a central processing unit, a storage section, and a measuring means.

<43>
An absorbent body in which a first absorbent core containing a first water-absorbing polymer and a second absorbent core containing a second water-absorbing polymer are laminated,
The second absorbent core has a region along the longitudinal direction in which the abundance ratio of the second water-absorbing polymer is lower than that in the surrounding area,
At least a portion of the first water-absorbing polymer is composed of a water-absorbing polymer of the same quality as the second water-absorbing polymer,
The average particle size of the first water-absorbing polymer is smaller than the average particle size of the second water-absorbing polymer.
<44>
The absorbent body according to <43>, wherein the second absorbent core includes two base sheets facing each other and a second water-absorbing polymer interposed between the two base sheets.
<45>
The absorbent body according to <43> or <44>, wherein the second absorbent core has the portion in the front and rear end regions in the longitudinal direction where the abundance ratio of the second water-absorbing polymer is lower than that in the surrounding area.
<46>
the second water-absorbing polymer is spherical;
The absorbent body according to any one of <43> to <45>, wherein the first water-absorbing polymer in the first absorbent core contains a pulverized non-spherical water-absorbing polymer.
<47>
The absorbent body according to any one of <42> to <46>, wherein the second absorbent core is thinner than the first absorbent core 3.

<48>
The absorbent body according to any one of <43> to <47>, wherein the second absorbent core is in contact with the non-skin facing surface of the first absorbent core.
<49>
The first absorbent core has at least one of the length in the vertical direction and the length in the horizontal direction shorter than the second absorbent core,
Said <43> or <43>, wherein a portion of the second absorbent core on which the first absorbent core is arranged has a portion where the second absorbent core 4 is exposed and the first absorbent core is not arranged. 47>.
<50>
The first absorbent core has both a length in the vertical direction and a length in the horizontal direction shorter than the second absorbent core,
The absorbent body according to any one of <43> to <49>, wherein the entire circumferential edge of the first absorbent core is located further inward than the circumferential edge of the second absorbent core.
<51>
The absorbent core according to any one of <43> to <50>, wherein the first absorbent core has a longer length in the horizontal direction on one end side in the vertical direction than on the other end side.
<52>
Any one of <43> to <51> above, wherein the first absorbent core has a region along the longitudinal direction where the core forming material of the first absorbent core is not present throughout the entire thickness direction of the first absorbent core. The absorbent body described in 1.
<53>
The absorbent according to any one of <43> to <52>, wherein the length of the region in which the second water-absorbing polymer contained in the second absorbent core is present is greater than the length in the longitudinal direction of the first absorbent core. .

1 Absorbent body 2 Absorbent core 3 First absorbent core 3F Fiber material 3N Forming material absent area 3P First water absorbent polymer 4S (4S1, 4S2) Two base sheets 4P Second water absorbent polymer 4P1 Recovery second water absorbent Polymer 10 absorber manufacturing equipment
20 First absorption core manufacturing section 22 Duct 40 Second absorption core manufacturing section 43 Spreading means 47 Collection means 63 First supply tank 431 Hopper 431a Discharge port 432 Conveyance means 433 Receiving means 471 Opening 472 Collection box 473 Shutter

Claims (8)

An absorbent body in which a first absorbent core containing a first water-absorbing polymer and a second absorbent core containing a second water-absorbing polymer are laminated,
The second absorbent core has a region along the longitudinal direction in which the abundance ratio of the second water-absorbing polymer is lower than that in the surrounding area,
At least a portion of the first water-absorbing polymer is composed of a water-absorbing polymer of the same quality as the second water-absorbing polymer,
The average particle size of the first water-absorbing polymer is smaller than the average particle size of the second water-absorbing polymer,
An absorbent body, wherein the first water-absorbing polymer contains a pulverized non-spherical water-absorbing polymer. The absorbent core according to claim 1, wherein the second absorbent core includes two base sheets facing each other and a second water-absorbing polymer interposed between the two base sheets. The absorbent body according to claim 1 or 2, wherein the second absorbent core has the portions in the front and rear end regions in the longitudinal direction in which the abundance ratio of the second water-absorbing polymer is lower than in the surrounding area. The absorbent body according to any one of claims 1 to 3, wherein the second water-absorbing polymer is spherical. An apparatus for producing an absorbent body formed by laminating a first absorbent core containing a first water-absorbing polymer and a second absorbent core containing a second water-absorbing polymer,
a first water-absorbent polymer supply section that supplies the first water-absorbent polymer to the first absorbent core;
a second water-absorbent polymer supply section that supplies a second water-absorbent polymer to the second absorbent core;
a recovery means for recovering the periodically removed second water-absorbing polymer;
Re-supply means for conveying the second water-absorbing polymer collected by the collection means to the first water-absorbing polymer supply section;
An apparatus for producing an absorbent body. The resupply means includes a recovery path connecting a first supply tank provided in the first water-absorbing polymer supply section and a recovery box provided in the recovery means, and a vacuum provided in the first supply tank. The manufacturing apparatus according to claim 5, comprising a conveying device. The manufacturing apparatus according to claim 6, wherein a sensor is installed in the recovery path. 8. Manufacture according to any one of claims 5 to 7, wherein the resupply means is configured to transport the second water-absorbing polymer entrained in a gas flow to the first water-absorbing polymer supply. Device.

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