RU2664339C1 - Absorbent product, method of manufacturing absorbent products and device for manufacturing absorbent products - Google Patents

Abstract

FIELD: manufacturing technology.

SUBSTANCE: method of manufacturing the absorbent members of the invention is a method for manufacturing absorbent members, comprising: feeding fibrous material (31) in a dispersed and air-weighed state to rotary drum (2) having a collection / accumulation recess (22) formed on its outer peripheral surface, and providing the accumulation of fibrous material (31) in the collecting / storing recess (22) by suction to form absorbent member (3) having a predetermined shape, wherein, by periodically changing the amount of fibrous material (31) fed per unit time, in accordance with the rotation / displacement period of the collecting / collecting recess (22), an absorbent member (3) has a part in which the surface density of fibrous material (31) is relatively high, and the portion in which the surface density of the fibrous material is relatively low.

EFFECT: method for manufacturing absorbent elements.

35 cl, 4 tbl, 24 dwg

Description

FIELD OF THE INVENTION

[0001]

The present invention relates to an absorbent element, a method for manufacturing absorbent elements, and a device for manufacturing absorbent elements.

State of the art

[0002]

In the art, as a device for manufacturing absorbent elements for absorbent articles, such as disposable diapers, sanitary napkins or urological pads, a device for manufacturing absorbent elements is known that includes a rotary drum having a catch / accumulation recess formed on its outer peripheral surface, wherein: the material of the absorbent element, such as cellulose, is supplied in a dispersed and air-suspended state Oyanii to the outer peripheral surface of the drum while rotating the rotating drum; provide the accumulation of material of the absorbent element in the recess for trapping / accumulation under the action of a suction force acting on the side of the lower surface of the recess for trapping / accumulation formed from a porous element having many suction holes formed therein; and the cluster, which is given a given shape, is removed from the recess for capture / accumulation to obtain an absorbent element. The absorbent element is used as is or when covered with a cover sheet, such as paper or breathable nonwoven, as the absorbent element of the absorbent article.

[0003]

One similar type of the proposed device for manufacturing absorbent elements is a device in which the lower surface of the capture / accumulation recess is formed with a first suction zone having a high fraction of the cross-section and a second suction zone having a lower fraction of the cross-section than the first suction zone, as a result, an absorbent element is made, which includes a part made with a partially increased absorbent capacity (cf. Patent Literature 1).

List of links

Patent Literature

[0004]

Patent Literature 1: JP 2004-65930A

SUMMARY OF THE INVENTION

[0005]

In accordance with the invention, there is provided a method of manufacturing absorbent elements, comprising: supplying fibrous material in a dispersed and air-suspended state to a rotating drum having a catch / accumulation recess formed on its outer peripheral surface, and providing fiber material to accumulate in the capture recess / accumulation by suction to obtain an absorbent element having a given shape, while by changing the amount of fiber of material fed per unit time is obtained an absorbent body having a portion in which the surface density of the fibrous material is relatively high, and a portion in which the surface density of the fibrous material is relatively low.

The invention also provides an absorbent element that has a new structure and which can be manufactured by a method of manufacturing absorbent elements or a manufacturing device according to the invention. That is, in accordance with the invention, an absorbent element is provided that includes a fibrous material and a water-absorbing polymer and which satisfies the following conditions AC.

Condition A: Each of the surface density of the fibrous material and the surface density of the water-absorbing polymer varies along the longitudinal direction of the absorbent element.

Condition B: In the longitudinal direction of the absorbent element, the part in which the surface density of the fibrous material is the highest coincides with the part in which the surface density of the water-absorbing polymer is the highest.

Conditions C: The uneven distribution coefficient, which is the ratio between the surface density in the part in which the surface density is the highest, and the surface density in the part in which the surface density is the lowest, is different for the fibrous material and the water-absorbing polymer.

[0006]

In accordance with the invention, there is also provided a device for manufacturing absorbent elements, including: a rotating drum having a plurality of pick-up / storage recesses formed on its outer peripheral surface at predetermined intervals; a channel that provides the supply of fibrous material as the material of the absorbent element in a dispersed and air-suspended state to the outer peripheral surface of the rotating drum; a fibrous material supply module that feeds the fibrous material into the channel, and a discharge means that ensures that the accumulation resulting from the accumulation of the fibrous material in the capture / accumulation recess exits the capture / accumulation recess in the form of an absorbent element. A device for manufacturing absorbent elements according to the invention provides the manufacture of absorbent elements, wherein each individual absorbent element has a part in which the surface density of the fibrous material is relatively high and a part in which the surface density of the fibrous material is relatively low due to a change in the amount of fibrous material supplied per unit time to the channel. The device for manufacturing absorbent elements according to the invention further includes a feed quantity control unit that determines a state of uneven distribution of the fibrous material in the absorbent element or accumulation and which, based on a certain uneven distribution state, provides a change in the amount of fibrous material supplied to the channel by the fiber material supply module.

Brief Description of the Drawings

[0007]

[Fig. 1] Fig. 1 is a schematic diagram illustrating an apparatus for manufacturing absorbent elements, preferably used for operating an embodiment of a method for manufacturing absorbent elements of the invention.

[Fig. 2] Fig. 2 is a perspective view illustrating the construction of a pick-up / storage recess in the manufacturing apparatus illustrated in Fig. 1.

[Fig. 3] Fig. 3 (a) is a graph illustrating how the supplied amount of fibrous material changes in a preferred embodiment; Fig. 3 (b) is a graph illustrating a change in the amount of fibrous material that reaches the outer the peripheral surface of the drum, in a preferred embodiment, and FIG. 3 (c) is a schematic diagram illustrating a length of a channel opening defined in a direction along the circumference of the drum, etc.

[Fig. 4] Fig. 4 is a perspective view illustrating an example of an absorbent member obtained by the invention.

[Fig. 5] Fig. 5 is a schematic diagram explaining a method for determining a surface density in a part in which a surface density of a fibrous material is lowest and a surface density in a part in which a surface density of a fibrous material is highest.

[Fig.6] Fig.6 (a) -6 (c) are side views illustrating channels with other shapes that are used in the Examples and Comparative Examples.

[Fig. 7] Fig. 7 illustrates graphs showing a state of uneven distribution of fibrous material in respective absorbent elements made in accordance with Examples 2-5.

[Fig. 8] Fig. 8 illustrates graphs showing the frequency of the degree of change — in 5% increments — of the surface density of the fibrous material in the respective absorbent elements made in accordance with Examples 2-5.

[Fig. 9] Fig. 9 illustrates graphs showing a state of uneven distribution of fibrous material and a state of uneven distribution of water-absorbing polymer in respective absorbent elements made in accordance with Examples 6 and 7.

[Figure 10] Figure 10 illustrates graphs showing the frequency of the degree of change — in 5% increments — of the surface density of the fibrous material and the surface density of the water-absorbing polymer in the respective absorbent elements made in accordance with Examples 6 and 7.

[Fig. 11] Fig. 11 is a schematic diagram illustrating an embodiment of an apparatus for manufacturing absorbent elements of the invention.

[Fig. 12] Fig. 12 (a) is a graph illustrating how the supplied amount of fibrous material changes in a preferred embodiment; Fig. 12 (b) is a graph illustrating a period corresponding to a catch / accumulation recess in in accordance with FIG. 12 (a), and FIG. 12 (c) is a schematic diagram illustrating a length of a channel hole defined in a direction along the circumference of the drum, etc.

[Fig. 13] Figs. 13 (a) to 13 (c) are graphs, each of which illustrates the height offset of the upper surface of each absorbent element, which is used to determine whether the uneven distribution of the fibrous material is appropriate or not.

[Fig. 14] Fig. 14 is a schematic diagram corresponding to Fig. 12 (a) illustrating an example of how the phase of the supplied quantity is shifted in accordance with the configuration of the uneven distribution state in the absorbent member.

[Fig. 15] Figs. 15 (a) and 15 (b) are side views illustrating other examples of absorbent elements that may be obtained by the invention.

Description of Embodiments

[0008]

In the apparatus for manufacturing absorbent elements disclosed in Patent Literature 1, the amount of absorbent element material accumulating in the capture / accumulation recess can be partially adjusted, and it is possible to manufacture an absorbent element in which the surface density of the material of the absorbent element is partially different. However, in order to change various characteristics, such as the ratio of the area of zones with different surface densities, the capture / accumulation cavity itself must be modified, which is extremely time-consuming.

[0009]

The invention relates to the development of a method of manufacturing absorbent elements and devices for manufacturing, providing the ability to solve problems of the usual prior art. The invention also relates to the implementation of an absorbent element having a new structure.

[0010]

The invention is described below in accordance with preferred variants of its implementation.

First described: a device for manufacturing absorbent elements, preferably used in one embodiment of the method of manufacturing absorbent elements according to the invention, and a device for manufacturing absorbent elements, which is one embodiment of a device for manufacturing absorbent elements according to the invention.

The device 1 for manufacturing absorbent elements illustrated in FIG. 1 is a device for manufacturing absorbent elements, preferably used in one embodiment of the method of manufacturing absorbent elements according to the invention. The device 1A for manufacturing absorbent elements illustrated in FIG. 11 is a device for manufacturing absorbent elements, which is one embodiment of a device for manufacturing absorbent elements according to the invention.

As illustrated in FIG. 1, the device 1 for manufacturing the absorbent elements of FIG. 1 (hereinafter also referred to as the “manufacturing device 1”) includes: a rotating drum 2 having a plurality of recesses 22 for collecting / accumulating formed on its outer peripheral surface at predetermined intervals; channel 4, which provides the supply of fibrous material 31 and water-absorbing polymer 32 as absorbent material in a dispersed and air-suspended state to the outer peripheral surface 2f of the rotary drum 2; a fibrous material supply module 5, which feeds the fibrous material 31 into the channel 4; an unloading blower device 6, which provides the output of the accumulation resulting from the accumulation of the fibrous material 31 and the water-absorbing polymer 32 in the capture / accumulation recess 22 from the capture / accumulation recess 22 in the form of an absorbent element 3, and a vacuum conveyor 7, which serves to as a means of transportation and is located under the rotating drum 2.

The apparatus 1A for manufacturing the absorbent elements of FIG. 11 (hereinafter also referred to as the “apparatus 1A for manufacturing”) includes, as illustrated in FIG. 11: a rotating drum 2 having a plurality of pick-up / storage recesses 22 formed on its outer peripheral surface at predetermined intervals; channel 4, which provides the supply of fibrous material 31, as the material of the absorbent element, in a dispersed and air-suspended state to the outer peripheral surface 2f of the rotary drum 2; a fibrous material supply module 5, which feeds the fibrous material 31 into the channel 4; discharge blower device 6, serving as discharge means, which provides for the output of the accumulation resulting from the accumulation of the fibrous material 31 and the water-absorbing polymer 32 in the capture / accumulation recess 22 from the capture / accumulation recess 22 in the form of an absorbent element 3; a vacuum conveyor 7, which serves as a means of transportation and is located under the rotary drum 2, and a feed quantity control unit 8A that controls the amount of fibrous material 31 to be fed from the fibrous material supply unit 5 to the channel 4.

[0011]

The rotary drum 2 of the manufacturing apparatus 1, 1A includes: a cylindrical drum body 20 made of a metal rigid element and an outer peripheral element 21 that is arranged to overlap the outer peripheral part of the drum body 20 and which forms the outer peripheral surface 2f of the rotating drum 2. The outer peripheral element 21 rotates in the direction of the arrow R about a horizontal axis by receiving power from a prime mover, such as an electric motor (Unillustrated), while the drum housing 20 is fixed and does not rotate.

As illustrated in FIG. 2, the outer peripheral element 21 has in its outer peripheral part: a porous plate 27 (porous element) and a plate 28 forming a contour that is fixed in a position in which it is superposed from the outer surface 27a of the porous plate 27. The lower surface of the capture / accumulation recess 22 is formed by a porous plate 27.

[0012]

The contour forming plate 28 has an outer surface 28a that forms the outer peripheral surface 2f of the rotary drum 2, and an inner surface 28b that faces the axis of rotation of the rotary drum 2, and also has spaces 280 between the outer surface 28a and the inner surface 28b, each of which has a shape corresponding to a three-dimensional shape inside the respective recesses 22 for capture / accumulation. The contour line 22L of each space 280 corresponds to the contour line of the recess 22 for collection / accumulation. As the plate 28 forming the contour, you can use, for example: a plate having holes (spaces 280, each of which has a shape corresponding to a three-dimensional shape inside the respective recesses 22 for collecting / accumulation), formed by machining a plate made, for example, from resin or metal such as stainless steel or aluminum; a plate made integrally by forming holes in the mold; a plate made by punching or etching, or a plate formed by superposing the aforementioned plates on top of each other.

[0013]

The porous plate 27 is an air-permeable plate that allows air from the outer side of the rotary drum 2 to be transmitted through suction from the side of the drum body 20, which holds the material of the absorbent element carried in the air flow without causing the penetration of the material of the absorbent element through it, and which allows only air to pass through it. The porous plate 27 has a plurality (large number) of suction holes (small holes) passing through the plate 27 in the thickness direction, and the holes are formed so that they are evenly distributed throughout the plate 27. When the recess 22 for capture / accumulation passes over the space A, which is formed in the rotary drum 2 and in which negative pressure is maintained, the suction openings function as ventilation openings for the air flow. The porous plate 27 of the manufacturing apparatus 1 has a constant fraction of the cross-sectional area over the entire zone, and no component, such as a suction force adjusting plate for partially changing the suction force, is located under the porous plate 27. In other words, in accumulation of the recess 22 of the device 1 for manufacturing a uniform suction force is created on the entire bottom surface.

As the porous plate 27, for example, a mesh plate made of metal or resin and a plate in which a plurality (large number) of small holes are formed by etching or punching in a plate made of metal or resin can be used.

[0014]

As illustrated in FIGS. 1 and 11, the drum body 20 has a plurality of independent spaces A, B, C and D separated by partitions 20p that are provided from the side of the central shaft of the rotating drum 2 toward the side of the outer peripheral surface 2f. A suction fan (not illustrated) is attached to a portion 222, which is the central shaft of the drum body 20. In the manufacturing apparatus 1, the pressure in each of the spaces A-D divided inside the rotary drum 2 can be controlled by actuating the suction fan. In the device 1A for manufacturing a damper, valve, etc., made with the possibility of regulating the area of the cross-section, are provided between the part 222, which is a Central rod, and each space, and when increasing / decreasing the cross-sectional area of the shutter can adjust the pressure in each of the spaces AD, divided inside the rotating drum 2.

In both manufacturing apparatuses 1, 1A, the suction force in the area of the space A, which is in the area in which the outer peripheral surface 2f is covered by the channel 4, is greater than the suction force in each of the zones of the spaces B-D. It should be noted that spaces C and D are zones including the place of movement of the absorbent element 3 in the recess 22 for collection / accumulation, and the area in front and behind the place of movement, and, thus, it is preferable that the pressure in them be zero or positive.

[0015]

As illustrated in FIGS. 1 and 11, the channel 4 in the manufacturing apparatus 1, 1A extends from the fiber material supply unit 5 to the rotary drum 2, and the opening of the channel 4 on the output side “covers” the outer peripheral surface 2f located above the space A, which is formed inside the rotating drum 2 and in which negative pressure is maintained. The fibrous material supply module 5 includes a chopper 51 as a fiberizing machine and is configured such that the sheet material 31A, which is a fibrous material, such as wood pulp, is introduced into the chopper 51 by means of material supply rollers 52, and fibrous material 31, obtained by separation into fibers in the grinder 51, is fed into the channel 4.

A dispersion tube 55 for supplying a water-absorbing polymer 32, which is another type of absorbent material, to a channel 4 is provided in a channel 4 between the rotary drum 2 and the fiber supply module 5. When the suction fan of the (non-illustrated) rotary drum 2 is driven, an air stream that allows the material of the absorbent element (fibrous material 31 and water-absorbing polymer 32) to pass to the outer peripheral surface 2f of the rotary drum 2 is created in the space inside the channel 4.

[0016]

The pressure tape 24 of the device 1, 1A for the manufacture of absorbent elements is an endless breathable or airtight tape. The tape covers the roller 25, the roller 26 and other rollers (not illustrated) and rotates, repeating the rotation of the rotating drum 2. In cases where the pressing tape 24 is an air-permeable tape, it is preferable that the tape does not allow the material of the absorbent element (fibrous material 31 and water-absorbing polymer 32), located in the recess 22 for capture / accumulation, to pass through it. Thanks to the pressure tape 24, the accumulation in the capture / accumulation recess 22 can be held inside the capture / accumulation recess 22 until the accumulation is transferred to the vacuum conveyor 7, even when the pressure in space B is set at atmospheric pressure.

[0017]

The vacuum conveyor 7 (conveying means) of the manufacturing device 1, 1A is located under the rotating drum 2 and is located next to the outer peripheral surface 2f located in the space C of the rotating drum 2, in which the pressure is set to zero (atmospheric pressure) or slightly increased pressure. The vacuum conveyor 7 includes: an endless breathable belt 73 and a vacuum chamber 74 located opposite the outer peripheral surface 2f of the rotary drum 2 on the other side of the breathable belt 73. A breathable cover sheet 35, such as tissue paper (tissue paper) or non-woven material is introduced onto the vacuum conveyor 7. This breathable cover sheet 35 is also liquid permeable.

[0018]

The discharge blower device 6 of the manufacturing apparatus 1, 1A functions as a discharge means that provides an outlet for the accumulation resulting from the accumulation of the material of the absorbent element (fibrous material 31 and water-absorbing polymer 32) in the capture / accumulation recess 22 from the recess 22 for capture / accumulation. The discharge blower 6 is located in the space C further inward than the outer peripheral element 21. The discharge blower 6 can blow air toward the side of the outer surface 27a from the side of the inner surface of the porous element, such as a porous plate forming the lower surface of the recess 22 for capture / accumulation, in which the material of the absorbent element accumulates, and air contributes to the exit of the cluster from the recess 22 for trapping I / accumulation.

[0019]

As illustrated in FIG. 1, the manufacturing apparatus 1 includes a feed quantity control unit 8 that controls the amount of fiber material 31 supplied from the fiber material supply unit 5 to the channel 4. In addition, as illustrated in FIG. 11, the device 1A for manufacturing includes a supply quantity control unit 8A that controls the amount of fibrous material 31 supplied from the fibrous material supply unit 5 to the channel 4. Although this is not illustrated in detail It is customary that each supply quantity control unit 8, 8A includes, for example: a computer having a display device; an interface that electrically connects a computer and another device, and a predetermined program installed on the computer.

The manufacturing apparatus 1A further includes a surface displacement measuring device 82. The signal from the surface displacement measuring device 82 is inputted to the computer of the supply quantity control unit 8A, and a change in the height of the upper surface of the absorbent element 3 along the X direction of movement of the absorbent element 3 moved on the transport means 7A is recorded in a storage device such as a hard disk drive ( HDD), random access memory (RAM) or solid-state drive (SSD), and is also displayed in the display device.

The computer of the feed quantity control unit 8, 8A controls the amount of sheet material 31A supplied to the shredder 51 by controlling the rotation of the drive motor 53 by providing a control signal to the drive motor 53, and thereby can control the amount of fibrous material 31 fed into the channel 4. Instead of a computer, a programmable controller (PLC) can be used.

[0020]

The drive motor 53 drives and rotates the two feed rollers 52, 52, which feed sheet material 31A, which is fibrous material 31, to the shredder 51. As the speed of the drive motor 53 increases, the amount of sheet material 31A fed to the shredder 51, increases, and thus increases the amount of fibrous material, such as cellulosic fiber, supplied per unit time to channel 4. On the other hand, as the frequency decreases by rotating the drive motor 53, the amount of sheet material 31A supplied to the shredder 51 is reduced, and thus, the amount of fibrous material, such as cellulosic fiber, supplied per unit time to the channel 4 is reduced.

[0021]

The device 1, 1A for manufacturing absorbent elements further includes a mechanism for producing a continuous absorbent element 30A by closing the upper and lower surfaces of the absorbent elements 3, discharged from the respective recesses 22 to capture / accumulation, covering sheets 35, 36. A covering sheet 36 that covers the surface of the absorbent element 3 from the side opposite to the side of the covering sheet 35 supplied to the vacuum conveyor 7 may be a side cover sheet 35, which after placing the absorbent element 3 in a portion central in the width direction on one surface of the cover sheet 35, are bent toward the side of the other surface. Alternatively, the cover sheet 36 may be a cover sheet 36 separate from the cover sheet 35 fed to the vacuum conveyor 7. Similarly to the cover sheet 35, the cover sheet 36 may be, for example, thin paper (tissue paper) or non-woven material, and preferably is breathable. This breathable cover sheet 36 is also liquid permeable.

The device 1, 1A for manufacturing absorbent elements further includes a cutting device 9 that cuts the continuous absorbent element 30A into absorbent elements 3, each of which has a length that allows it to be used in a separate absorbent article (hereinafter also referred to as “length for one absorbent article "). As the cutting device 9, one of the various types of known cutting means used to make absorbent articles and absorbent elements can be used, and, for example, as illustrated in FIGS. 1 and 11, a device that includes a cutting roller 91 having a cutting knife 92, and a support roller 93 for receiving the knife and which sequentially cuts the continuous absorbent element 30A at constant intervals due to the rotation of the rollers.

[0022]

A method for continuously manufacturing absorbent elements 3 by means of the aforementioned device 1 for manufacturing absorbent elements, that is, one embodiment of a method for manufacturing absorbent elements according to the invention, is described below. Below, this embodiment is called the first embodiment.

For the manufacture of absorbent elements 3 by means of the aforementioned manufacturing device 1, the rotary drum 2 is rotated and the suction fan is driven to create negative pressure in space A. In addition, the discharge blower device 6, the vacuum conveyor 7, the conveyor belt 7A are driven located next to the vacuum conveyor 7, and the cutting device 9.

When the suction fan is driven, a uniform suction force is created in the entire area of the lower surface of the capture / accumulation recess 22 located above the space A, and the air flow that passes to the outer peripheral surface of the rotating drum 2 is created inside the channel 4.

[0023]

When the feed rollers 52 of the fiber supply module 5 are driven and the sheet material 31A, which is the fiber material 31, is introduced into the chopper 51, the fibrous material 31 obtained by dividing into fibers by the chopper 51 is fed into the channel 4. The fibrous material 31, fed into the channel 4, goes into a dispersed and air-suspended state and is transferred to the air flow passing inside the channel 4, and is fed towards the outer peripheral surface of the rotating drum 2.

[0024]

In the first embodiment, the amount of fibrous material supplied per unit time to the rotating drum 2 in a dispersed and air-suspended state is periodically changed. That is, the amount of fibrous material 31 supplied per unit time to channel 4 is periodically changed. More specifically, when using a computer included in the feed quantity control unit 8, the amount of fibrous material 31 supplied per unit time to the channel 4 is periodically changed by periodically changing the rotation speed of the feed rollers 52 for supplying the material, and thereby periodically changing the feed rate of the fibrous sheet material 31A to the shredder 51, serving as a fiberizing machine. The program for providing such a change is pre-installed in the computer of the unit 8 for controlling the supplied quantity. The speed of the feed rollers 52 can be periodically changed using a programmable computer.

[0025]

In the first embodiment, the mass of the fibrous material 31 supplied to the channel 4 is periodically changed by the supply quantity control unit 8 in accordance with the sequence illustrated in FIG. 3 (a), and therefore the mass of the fibrous material 31 that reaches the outer peripheral surface rotating drum 2, periodically changes in accordance with the sequence illustrated in figure 3 (b).

The fibrous material 31 is obtained by dividing the sheet material 31A into fibers by means of a chopper 51; however, when sheet cellulose is used as the sheet material 31A, it is difficult to divide the sheet cellulose into fibers to a state in which the cellulose fibers are separated and the fibrous material 31 has the appearance of flakes, while the cellulose fibers are roughly tangled. Thus, the fibrous material 31 has a low apparent density compared to the water-absorbing polymer 32, which is in the state of particles, and is easily influenced by the air flow. As a result, the wave shape and amplitude in FIG. 3 (a) do not correspond to the wave shape and wavelength in FIG. 3 (b), and the degree of change in the amount of fibrous material that reaches the outer peripheral surface of the drum is small compared to the degree of change in the amount of fibrous material fed into the duct 4. In other words, the difference between FIGS. 3 (a) and 3 (b) is due to the fact that during the passage of the fibrous material 31 through the duct 4, the distribution of the fibrous material is leveled due to the effect of diffusion by the air flow. It is difficult to accurately predict the scattering effect, and if the distribution becomes completely uniform, it becomes impossible to ensure the intended distribution of the fibrous material for the absorbent element being manufactured. In order to maintain the state illustrated in FIG. 3 (b) and to make an absorbent member in which the fibrous material is not evenly distributed, it is preferable that the degree of change in the amount of fibrous material supplied to the channel 4 is large enough and the scattering effect in the channel 4 is reduced.

The sequence illustrated in FIG. 3 (a) is a sequence in which the step of supplying a relatively small amount of fibrous material 31 to the channel 4 and the step of supplying a relatively large amount of fibrous material 31 to the channel 4 are repeated alternately, and the fibrous material 31 is fed continuously simultaneously changing the quantity supplied. Instead, the fibrous material 31 may be fed into the channel 4 in accordance with a sequence in which the step of not supplying the fibrous material 31 to the channel 4 and the step of supplying the fibrous material 31 to the channel 4 are repeated alternately.

[0026]

The feed rollers 52 in the manufacturing apparatus 1, 1A are moved in cooperation with each other by connecting them, for example, via gears and rotated in opposite directions at the same peripheral speed by a single drive motor 53. A drive motor 53 is preferably used as the drive motor 53. Various known devices, such as an input / output interface and a servo amplifier, are located between the drive motor 53 and the supply quantity control unit 8, 8A in accordance with, for example, the type of rotation control signal that is output by the supply quantity control unit 8, 8A and the type of motor .

When changing the amount of sheet material 31A supplied to the shredder 51 in accordance with a sequence such as that illustrated in FIG. 3 (a), it is preferable that the drive motor 53 and the gear ratio of the gears used for coupling have characteristics and adjusting parameters, providing the ability to achieve excellent response to guarantee high "sensitivity" of the feed rollers 52.

[0027]

The vertical axis in the graph of FIG. 3 (a) shows the amount (mass a) of fibrous material 31 supplied per unit time to channel 4, and the vertical axis in the graph of FIG. 3 (b) shows the amount (mass b) of fibrous material 31 which reaches the outer peripheral surface of the drum 2. The duration T shown in FIGS. 3 (a) and 3 (b) shows the interval corresponding to the catch / accumulation recess 22 that passes through the portion covered by the channel 4 in accordance with rotation rotating drum 2 and also shows n the duration of one rotation / movement period of the recess 22 for capture / accumulation. More specifically, as illustrated in FIG. 3 (c), this period corresponds to the time from the moment when a specific location P1 of one capture / storage recess 22a, for example, a front end in the rotation direction R, passes by a specific location P2 of channel 4 at the direction along the circumference of the rotary drum 2, until the same specific location P1 of the next capture / storage recess 22b passes by the same specific location P2.

[0028]

In the first embodiment, the amount of fibrous material 31 supplied per unit time to the channel 4 is periodically changed in accordance with the rotation / movement period of the catch / accumulation recess 22.

In the first embodiment, due to the periodic change in the amount of fibrous material 31 supplied per unit time to the channel 4, it is possible to form in a cluster, the formation of which is ensured by accumulation in the capture / accumulation recess 22, of a part in which the accumulated amount of fibrous material 31 is small , and the part in which the accumulated amount of fibrous material 31 is large; thus, a part in which the surface density of the fibrous material is relatively low, and a part in which the surface density of the fibrous material is relatively low are formed in the absorbent member 3 obtained by discharge from the recess 22 for collection / storage.

In addition, in accordance with the first embodiment, even in the case where the manufacturing speed of the absorbent elements 3 changes, the same absorbent elements 3 can be obtained by appropriately adjusting the period and amount of fibrous material 31 supplied to the channel 4.

[0029]

FIG. 4 is a perspective view illustrating an example of an absorbent member 3 made by the method of the first embodiment.

In the absorbent element 3 illustrated in FIG. 4, a high surface density part 33 in which the surface density of the fibrous material is relatively high is formed on the side of one end 3a of the capture / accumulation recess 22, which corresponds to the front end f in the direction of rotation, and a low surface density portion 34 in which the surface density of the fibrous material is relatively low is formed on the side of the other end 3b of the capture / storage recess 22 i, which corresponds to the trailing end of r in the direction of rotation. The absorbent element 3 has a longitudinal direction 3X corresponding to a direction along the circumference of the rotating drum 2, and a width direction 3Y orthogonal to the longitudinal direction. When transporting the absorbent element 3 by means of a vacuum conveyor 7 and a conveyor belt 7A that serve as conveying means, the longitudinal direction 3X of the absorbent element 3 extends along the conveying direction X, and the side of this one end 3a having a high surface density portion 33 is oriented towards to the side downstream in the conveying direction, as illustrated in FIG.

As illustrated in FIG. 1, the absorbent elements 3 obtained as described above are covered with cover sheets 35, 36 and converted into a continuous absorbent element 30A, and then the continuous absorbent element is cut into predetermined lengths by means of a cutting device 9 for receiving absorbent elements 30 covered with covering sheets. The absorbent member is included in an absorbent article, such as a disposable diaper.

[0030]

The absorbent member 3 or the absorbent member 30, the core of which is formed by the absorbent member 3, is preferably used as the absorbent member of the absorbent article. An absorbent article is mainly used to absorb and retain the body fluid, such as urine or menstrual blood, released from the body. Examples of absorbent articles include disposable diapers, sanitary napkins, urological and panty liners for everyday use, but this is not a limitation, and absorbent articles broadly encompass articles used to absorb fluid released from the human body.

[0031]

The absorbent element 3 or the absorbent element 30, the core of which is formed by the absorbent element 3, includes a high surface density part 33 having a relatively high surface density and a low surface density part 34 having a relatively low surface density and an amount of accumulated absorbent material element differs in these parts. Thus, from the point of view of maximizing the characteristics of the absorbent element in use, it is preferable that when the absorbent element is specifically used in a disposable diaper, the absorbent element 3 is used by incorporating it into the absorbent article so that the absorbent element portion 33 having a high surface density, was located on the side of the abdomen (front side) and part 34 with low surface density was located on the back (back side).

It is preferable to perform part with a high surface density and part with a low surface density, in which the surface densities of the fibrous material are different, in the absorbent element 3 also for reasons related to the fact that, for example, it will be easy to provide high absorbency in the necessary parts while reducing absorbency in parts in which it is not so necessary, resulting in a decrease in the total amount of material used. It should be noted that the absorbent element 3 can be used as the absorbent element of the absorbent product even without closing it with the cover sheets 35, 36.

[0032]

Both in the manufacturing method and in the manufacturing device according to the invention, from the point of view of the relationship between the change in the supplied amount of the fibrous material 31 and the difference in the surface density of the fibrous material in the absorbent element 3, the ratio of the length of the channel opening, determined in the direction along the circumference of the drum, to the length recesses 22 for capture / accumulation, determined in the direction along the circumference of the drum, is preferably 2.0 or less, more preferably 1.5 or less. In addition, from the point of view of the relationship between the accumulation rate of the fibrous material and the speed according to which the material is carried by air in the channel 4, the above ratio is preferably greater than 0, more preferably 0.1 or more.

As illustrated in FIGS. 3 (c) and 12 (c), the length of the channel hole, determined in the direction along the circumference of the drum, is the distance between both ends 4f and 4r of the hole 4e of the channel 4, determined in the direction along the circumference of the rotating drum from the side of the rotating drum and measured along the outer peripheral surface of the rotating drum. The length of the capture / accumulation recess 22, determined in the direction along the circumference of the drum, is the distance between both ends f and r of the capture / accumulation recess 22, determined in the direction along the circumference of the drum and measured along the outer peripheral surface of the rotating drum.

[0033]

In order to change the amount of fibrous material 31 supplied to the channel 4 and to produce an absorbent element in which the fibrous material is not evenly distributed, it is preferable that the parts in which the concentration of the fibrous material is high and the parts in which the concentration is low reach the outer the peripheral surface of the rotating drum 2 is undulating. In addition, it is preferable that parts (parts with high surface density) in which the surface density of the fibrous material is relatively high, and parts (parts with a low surface density) in which the surface density of the fibrous material is relatively low, are wave-shaped on the outer peripheral surface of the rotating drum 2.

[0034]

In addition, in the absorbent element made in accordance with the invention, the ratio of the surface density in the part in which the surface density of the fibrous material is highest to the surface density in the part in which the surface density of the fibrous material is the lowest is preferably 1.5 or more more preferably 2 or more and preferably 30 or less. In addition, for reasons related to the strength of the absorbent element, it is preferable that the surface density in the part in which the surface density of the fibrous material is the lowest is from 100 to 3000 g / m ² .

The content (mass) of the fibrous material included in each absorbent element depends on the application / use of the absorbent article. The surface density in the part in which the surface density of the fibrous material is the highest is determined based on the content of the fibrous material included in each absorbent element, the surface density in the part in which the surface density of the fibrous material is the lowest, and the preferred ratio of surface densities.

[0035]

The surface density in the part in which the surface density of the fibrous material is the highest, and the surface density in the part in which the surface density of the fibrous material is the lowest, is determined as described below. As illustrated in FIG. 5, straight lines C extending along the width direction 3Y are drawn at intervals of 30 mm from a longitudinally defined 3X, one end 3a of the absorbent member 3, and the absorbent member 3 is divided into a plurality of parts 3A-3F with straight lines C serving as boundaries. The area and mass of the fibrous material included in these parts is determined for each of the separated parts, and the surface density is calculated based on the mass and area that were determined. The surface density of the separated part, in which the calculated surface density is the highest, is considered as the surface density in the part in which the surface density of the fibrous material is the highest. The surface density of the separated part, in which the calculated surface density is the lowest, is considered as the surface density in the part in which the surface density of the fibrous material is the lowest. It should be noted that, as illustrated by the dashed line in FIG. 5, if the absorbent element 3 includes a part 3G whose length from the last straight line Ce is less than 30 mm, then the absorbent element 3 is not separated by a straight line Ce, but instead, the 3G portion is considered as part of the previous 3F portion, and the surface density of the 3F portion is calculated. In cases where the absorbent element is intended for the absorbent article, the end of the absorbent element closer to the abdomen side (front side) of the carrier in the front to back direction is considered one end 3a of the absorbent element 3 in the longitudinal direction 3X. If the relationship with the front / rear sides of the carrier is unknown, the end corresponding to the end f of the capture / accumulation recess 22 front in the direction of rotation is considered as this one end. If this is also unknown, then an arbitrary end in the longitudinal direction is considered given one end 3a.

[0036]

In both the manufacturing method and the manufacturing device according to the invention, in addition to supplying the fibrous material 31 to the channel 4, it is preferable to continuously supply the water-absorbing polymer 32 with a constant supply amount. The water-absorbing polymer 32 is introduced, for example, from the aforementioned dispersion tube 55 and is fed into the air stream carrying the fibrous material 31.

Even when the water-absorbing polymer 32 is fed continuously with a constant supply amount, a relatively larger amount of water-absorbing polymer 32 will be included in parts in which the concentration of fibrous material is high in the air flow carrying the fibrous material 31 than in parts in which the concentration is low . This is because, in parts in which the concentration of the fibrous material is high, the fibrous material 31 serves as a carrier for transferring the water-absorbing polymer 32. Thus, as the absorbent element 3, an absorbent element can be obtained that includes a larger amount of the water-absorbing polymer in the part in which the surface density of the fibrous material is relatively high than the part in which the surface density of the fibrous material is relatively low Coy.

As described above, in accordance with the method of the present embodiment, an absorbent element can be obtained in which the water-absorbing polymer is distributed unevenly, even without performing means for changing the supplied amount, for the device for supplying the water-absorbing polymer 32.

[0037]

In addition, according to the method of the first embodiment, an absorbent element can be obtained in which the water-absorbing polymer is distributed unevenly and the phase of the uneven distribution of the fibrous material coincides with the phase of the uneven distribution of the water-absorbing polymer, even without performing means for changing the supplied amount, for the device for water-absorbing polymer supply 32.

In addition, a change in the surface density of the water-absorbing polymer depends on a change in the amount of fibrous material, as illustrated in FIG. 3 (b), and therefore, an absorbent element can be obtained in which the surface density of the fibrous material and the surface density of the water-absorbing polymer change continuously and smoothly.

[0038]

When the absorbent element is obtained by supplying a water-absorbing polymer in accordance with a preferred embodiment of the invention, both the fibrous material and the water-absorbing polymer are distributed unevenly, and their phases of uneven distribution coincide with each other (cf. FIG. 9). In addition, it is possible to achieve a distribution in which the surface density changes continuously and smoothly.

Thus, when using the absorbent member included in the absorbent article, there is no inconvenience when wearing even when the absorbed amount is large. In addition, even in cases where no water-absorbing polymer is supplied, an absorbent article can be obtained that does not cause any inconvenience when worn.

[0039]

According to a preferred embodiment of the method of manufacturing the absorbent elements according to the invention, an absorbent element including a fibrous material and a water-absorbing polymer can be obtained, wherein: each of the surface density of the fibrous material and the surface density of the water-absorbing polymer varies along the longitudinal direction of the absorbent element; in the longitudinal direction of the absorbent element, the part in which the surface density of the fibrous material is the highest coincides with the part in which the surface density of the water-absorbing polymer is the highest, and the uneven distribution coefficient, which is the ratio between the surface density in the part in which the surface density is the highest, and the surface density in the part in which the surface density is the lowest differs for fibers material and water-absorbing polymer. In this absorbent element, it is preferable that the uneven distribution coefficient for the fibrous material is greater than the uneven distribution coefficient for the water-absorbing polymer.

An “uneven distribution coefficient for the fibrous material” is the ratio of the surface density of the fibrous material in the part in which the surface density of the fibrous material is the surface density of the fibrous material in the part in which the surface density of the fibrous material is the lowest. “Uneven distribution coefficient for a water-absorbing polymer” is the ratio of the surface density of the water-absorbing polymer in the part in which the surface density of the water-absorbing polymer is the highest to the surface density of the water-absorbing polymer in the part in which the surface density of the water-absorbing polymer is the lowest. The ratio of the uneven distribution coefficient for the fibrous material to the uneven distribution coefficient for the water-absorbing polymer is preferably 1.05 or more, more preferably 1.1 or more, and preferably 10 or less, more preferably 5 or less.

[0040]

The following describes a method for continuously manufacturing absorbent elements by means of the aforementioned absorbent element manufacturing apparatus 1A, which is one embodiment of an absorbent element manufacturing apparatus according to the invention. By this method, it is also possible to obtain an absorbent element 3 similar to that illustrated in FIG. 4, as in the aforementioned first embodiment.

For the manufacture of absorbent elements 3 by means of the aforementioned manufacturing device 1A, the rotary drum 2 is rotated and the suction fan is driven to create negative pressure in space A. In addition, the discharge blower device 6, the vacuum conveyor 7, the conveyor belt 7A are driven located next to the vacuum conveyor 7, and the cutting device 9.

When the suction fan is driven, a uniform suction force is created in the entire area of the lower surface of the capture / accumulation recess 22 located above the space A, and an air flow that passes to the outer peripheral surface of the rotary drum 2 is created inside the channel 4. When the feed rollers 52 52 of the fiber supply module 5 are driven, and the sheet material 31A, which is the fiber material 31, is introduced into the shredder 51, the fiber material 31, is obtained fiber separation by means of a grinder 51, is fed into channel 4. The fibrous material 31 supplied to channel 4 goes into a dispersed and air-suspended state and is transferred to the air flow passing inside channel 4 and is fed towards the outer peripheral surface of the rotating drum 2.

[0041]

In this manufacturing apparatus 1A, the supply quantity control unit 8A periodically changes the amount of fibrous material supplied per unit time to the rotary drum 2 in a dispersed and air-suspended state. That is, the amount of fibrous material 31 supplied per unit time to channel 4 changes periodically. More specifically, when using a computer included in the supply quantity control unit 8A, the amount of fibrous material 31 supplied per unit time to the channel 4 is periodically changed by periodically changing the speed of the feed rollers 52, 52 for supplying the material, and thereby periodically changing the feed rate of the fibrous sheet material 31A to the shredder 51 serving as a fiberizing machine. The program for providing such a change is pre-installed in the computer of the supply quantity control unit 8A. The speed of the feed rollers 52, 52 can be periodically changed using a programmable controller.

[0042]

For example, the feed quantity control unit 8A periodically changes the speed of the feed rollers 52, 52 for feeding material in accordance with the sequence illustrated in FIG. 12 (a), and thereby the mass a of the fibrous material 31 fed into the channel 4 by means of the unit 8A controlling the amount supplied is periodically changed in accordance with the same sequence.

The sequence illustrated in FIG. 12 (a) is a sequence in which the step of supplying a relatively small amount of fibrous material 31 to the channel 4 and the step of supplying a relatively large amount of fibrous material 31 to the channel 4 are repeated alternately, and the fibrous material 31 is fed continuously simultaneously changing the quantity supplied. Instead, the fibrous material 31 may be supplied to the channel 4 in accordance with a sequence in which the step of not supplying the fibrous material 31 to the channel 4 and the step of supplying the fibrous material 31 to the channel 4 are repeated alternately.

[0043]

The vertical axis in the graph of FIG. 12 (a) shows the speed with which the sheet material 31A, which is the fibrous material 31, is introduced into the shredder 51 by means of the feed rollers 52, 52, and the amount (mass a) of the fibrous material 31 supplied per unit time in channel 4, changes in the same way. The graph of FIG. 12 (b) shows the period corresponding to the capture / accumulation recess 22 that passes through the portion covered by channel 4. As illustrated in FIGS. 3 (c) and 12 (c), for example, a single period corresponds to the time from the moment when a certain place P1 of one recess 22a for collection / accumulation, for example, the front end in the direction of rotation R, passes by a certain place P2 of the channel 4 in the direction along the circumference of the rotating drum 2, until the moment when the same defined location P1 after blowing recess 22b for capture / accumulation will pass by the same specific location P2.

During operation of the manufacturing apparatus 1A, as illustrated in FIGS. 12 (a) and 12 (b), the feed quantity control unit 8A synchronizes a period of a change in the feed rate of the fibrous sheet material 31A to the shredder 51 with a period of which the recess 22 for capture / accumulation passes through the part closed by the channel 4.

[0044]

Due to the periodic change in the amount of fibrous material 31 supplied per unit time to channel 4, by means of block 8A, the supplied quantity can be formed in a cluster, the formation of which is ensured by accumulation in the recess 22 for collection / accumulation, of a part in which the accumulated amount of fibrous material 31 is small, and the part in which the accumulated amount of fibrous material 31 is large; thus, a part in which the surface density of the fibrous material is relatively low, and a part in which the surface density of the fibrous material is relatively low are formed in each of the absorbent elements obtained by unloading from the respective recesses 22 for collection / accumulation. FIG. 4 is a perspective view illustrating an example of an absorbent member 3 made by the apparatus 1 of the present embodiment.

In the absorbent element 3 illustrated in FIG. 4, a high surface density part 33 in which the surface density of the fibrous material is relatively high is formed on the side of one end 3a of the capture / accumulation recess 22, which corresponds to the front end f in the direction of rotation, and a low surface density portion 34 in which the surface density of the fibrous material is relatively low is formed on the side of the other end 3b of the capture / storage recess 22 i, which corresponds to the trailing end of r in the direction of rotation. The absorbent element 3 has a longitudinal direction 3X corresponding to a direction along the circumference of the rotating drum 2, and a width direction 3Y orthogonal to the longitudinal direction. When transporting the absorbent element 3 by means of a vacuum conveyor 7 and a conveyor belt 7A that serve as conveying means, the longitudinal direction 3X of the absorbent element 3 extends along the conveying direction X, and the side of this one end 3a having a high surface density portion 33 is oriented towards to the side downstream in the conveying direction, as illustrated in FIG.

As illustrated in FIG. 11, the absorbent elements 3 obtained as described above are covered with cover sheets 35, 36 and converted into a continuous absorbent element 30A, and then the continuous absorbent element is cut into predetermined lengths by means of a cutting device 9 for receiving absorbent elements 30 covered with covering sheets. The absorbent member is included in an absorbent article, such as a disposable diaper.

[0045]

In accordance with a signal that is input from the surface displacement measuring device 82, the supply quantity control unit 8A registers a height offset of the upper surface of the absorbent member 3 transported by the conveyance means. 13 (a) illustrates a graph of the vertical displacement of the upper surface of the absorbent element 3, which is registered in the storage device of the supply quantity control unit 8A. Each of the numbers from 0 to 360 on the horizontal axis of Fig. 13 (a) shows 1/360 of the length of time of one cutting period by the cutting roller 91 or one period corresponding to a recess for capture / accumulation, similar to that described above; each point 0 on the horizontal axis represents a point in time when a determination signal is input from a sensor that has detected a reference position provided on a cutting roller or a rotating drum. Instead, a rotating position encoder 83 may be provided on the axis of the cutting roller 91 of the cutting device, and the duration of the pulse output by the rotating position encoder 83 and corresponding to one revolution of the cutting roller 91 can be considered as a duration from 0 to 360 on the horizontal axis.

In the storage device of the supply quantity control unit 8A, a preferred range of heights of the upper surface at each of a plurality of points is stored in advance within a duration of 0 to 360 on a horizontal axis in accordance with a predetermined absorbent element to be manufactured. It can be determined whether each absorbent element 3 made has the shape of a given absorbent element 3 or not according to whether the values for each absorbent element actually measured during the manufacture of the absorbent element 3 correspond to the stored values or not. As the surface displacement measuring device 82, a laser displacement sensor can be used.

For example, if the shape of the absorbent element 3 determined by the values inputted from the surface displacement measuring device 82 is the shape illustrated in FIG. 13 (b), even though the absorbent element 3 to be manufactured must have a shape, illustrated in FIG. 13 (a), the phase of the supplied quantity is shifted in accordance with the configuration of the uneven distribution state in the absorbent member, as illustrated in FIG. The direction in which the phase is shifted is the direction in which the uneven distribution of the fibrous material in the absorbent element being manufactured approaches the uneven distribution in the predetermined absorbent element.

[0046]

As described above, according to the manufacturing apparatus 1A of the present embodiment, an absorbent member can be manufactured in which a large amount of absorbent member material will be unevenly distributed in a predetermined part of one absorbent member, simply by changing the amount of fibrous material supplied per unit time. In addition, by monitoring the state of uneven distribution in the manufactured absorbent element 3 using the device 82 measuring the surface displacement, etc. and changes in the amount of fibrous material supplied to the channel by the fibrous material supply module in accordance with the uneven distribution state, absorbent elements in which the fibrous material is distributed unevenly in a predetermined state can be continuously and stably produced.

[0047]

The absorbent member 3 or the absorbent member 30, the core of which is formed by the absorbent member 3, is preferably used as the absorbent member of the absorbent article. In addition, the absorbent element 3 or the absorbent element 30, the core of which is formed by the absorbent element 3, made by the manufacturing apparatus 1A, includes a high surface density part 33 having a relatively high surface density and a low surface density part 34 having relatively low surface density, and the amount of accumulated material of the absorbent element is different in these parts. It should be noted that the absorbent element 3 can be used as the absorbent element of the absorbent product even when it is not covered by the cover sheets 35, 36.

[0048]

The absorbent element 3 to be manufactured may have the shape illustrated in FIG. 13 (b) or FIG. 13 (c), or the shape illustrated in FIG. 15 (a) or FIG. 15 (b).

The absorbent member illustrated in FIG. 13 (b) has: a high surface density part 33 in which the surface density of the fibrous material is highest, in a part central in the longitudinal direction 3X, which corresponds to the circumferential direction of the rotating drum 2, and a part 34 with a low surface density, in which the surface density of the fibrous material is the lowest, on both sides of the portion 33 with a high surface density in the longitudinal direction 3X.

The absorbent member illustrated in FIG. 15 (a) has: a high surface density part 33, in which the surface density of the fibrous material is highest, in a part central in the longitudinal direction 3X, which corresponds to the circumferential direction of the rotating drum 2, part 34 with a low surface density in which the surface density of the fibrous material is the lowest, from the side of one end in the longitudinal direction 3X and part 38 with an intermediate surface density in which the surface Single density of the fibrous material less than 33 parts of high surface density, and higher than the lowest portion 34 with a surface density from the other end in the longitudinal direction of 3X.

The absorbent element illustrated in FIG. 15 (b) has a plurality of high surface density parts 33 formed in a state in which they are separated from each other in the 3X longitudinal direction, which corresponds to the circumferential direction of the rotating drum 2. In the absorbent element, illustrated in FIG. 15 (b), all three parts other than the two high surface density parts 33 are low surface density parts 34 in which the surface density of the fibrous material is not zkaya, but one or two of these three parts may be a portion 38 of the intermediate surface density, wherein the surface density of the fibrous material less than 33 parts of high surface density, and higher than 34 parts of a low surface density

[0049]

An absorbent article in which an absorbent member manufactured by a manufacturing method or device for manufacturing according to the invention is included, or an absorbent member according to the invention typically includes a top sheet, a back sheet and a liquid retaining member, an absorbent member located between the top sheet and the back by sheet. The upper and lower surfaces of the absorbent element may be covered by one or more covering sheets. The back sheet may or may not be permeable to water vapor. The absorbent article may further include elements of various types depending on the particular application of the absorbent article. Similar elements are known to those skilled in the art. For example, in cases where the absorbent article is used as a disposable diaper or sanitary napkin, one or more pairs of sealed protective elements may be located on the outside with respect to the respective lateral sides of the absorbent element, which are standing.

[0050]

Regarding the fibrous material and the water-absorbing polymer used in the invention, the various materials commonly used for absorbent elements of absorbent articles, such as sanitary napkins, panty liners for everyday use, and disposable diapers can be used without particular limitation, with examples of this include staple fibers from cellulose fibers, such as cellulose fiber, hydrated cellulose fiber or cotton fiber, or staple fibers from synthetic fibers such as polyethylene. The aforementioned fiber of only one type may be used, or two or more types may be used in combination. Preferably, part of the fibrous material or all of the fibrous material is / is cellulosic fiber, and the proportion of cellulosic fiber in the fibrous material is preferably from 50 to 100% by mass, more preferably from 80 to 100% by mass, even more preferably 100% by mass . Other materials other than the fibrous material, such as a deodorizing material or an antibacterial agent, can be fed into the channel if necessary. In addition, it should be noted that the water-absorbing material may or may not be supplied.

[0051]

Examples of the water-absorbing polymer include sodium polyacrylate, a copolymer of acrylic acid and vinyl alcohol, a crosslinked sodium polyacrylate, a grafted copolymer of starch and acrylic acid, a copolymer of isobutylene and maleic anhydride and their saponification products, and polyaspartic acid. As for the fiber and the water-absorbing polymer, only one type can be used, or two or more types can be used in combination.

[0052]

A method of manufacturing absorbent elements, an absorbent element and a device for manufacturing absorbent elements according to the invention are not limited to the above embodiments and can be modified accordingly.

For example, an absorbent element in which the location of the part with a high surface density differs from the position of this part in the absorbent element illustrated in FIG. 4 can be manufactured by changing the amount of fibrous material 31 fed into the channel 4 by means of the feed quantity control unit 8 in accordance with a sequence different from the sequence illustrated in figure 3 (a). In addition, instead of changing the amount of sheet material 31A supplied to the shredder 51, the amount of fibrous material 31 fed to the channel 4 can be periodically changed in accordance with other methods. For example, a shutter may be provided directly behind the chopper 51, and the amount of fibrous material 31 fed into the channel 4 can be periodically changed by opening / closing the shutter.

In the rotary drum of the device for manufacturing absorbent elements illustrated in FIG. 1, a plurality of recesses for collection / accumulation, each of which provides the formation of an absorbent element for one absorbent article, are formed at intervals between them in the direction along the circumference of the rotary drum. However, the rotary drum to be used in the device for manufacturing absorbent elements according to the invention or in the method for manufacturing absorbent elements according to the invention may have one continuous recess for collecting / accumulating along the circumferential direction and may provide the formation of a continuous absorbent element in which absorbent elements for a plurality of absorbent articles are formed adjacent to each other.

In addition, the invention can be implemented in combination with the method disclosed in Patent Literature 1. The lower surface of the capture / accumulation recess 22 may be formed with a first suction zone having a large fraction of the cross-section and a second suction zone having a smaller fraction of the cross-section. sections compared to the first suction zone, and the accumulation of fibrous material in both of these suction zones can be ensured.

In addition, an absorbent element that does not include a water-absorbing polymer can be manufactured by supplying fibrous material to the channel without supplying a water-absorbing polymer.

[0053]

In the manufacturing apparatus 1A of the above embodiment, the surface displacement measuring apparatus is used to determine a state of uneven distribution of the fibrous material in the absorbent member. Instead, image processing or a capacitive sensor can be used.

In image processing, for example, the surface density of the fibrous material can be determined by the darkness / density of the absorbent element in the image captured by the image capturing means. A capacitive sensor is preferred for reasons that it is suitable for measuring insulating materials such as cellulosic fibers, such as cellulosic fibers, hydrated cellulose fibers or cotton fibers, and synthetic fibers, such as polyethylene, which are used as materials for absorbent articles. .

[0054]

In connection with the above-described embodiments of the invention, the following additional features are further disclosed (manufacturing methods of absorbent elements, absorbent elements, devices for manufacturing absorbent elements, etc.).

{one}

A method of manufacturing absorbent elements, including

supplying fibrous material in a dispersed and air-suspended state to a rotating drum having a catch / accumulation recess formed on its outer peripheral surface, and

ensuring the accumulation of fibrous material in the recess for collection / accumulation by suction to obtain an absorbent element having a given shape, while

by periodically changing the amount of fibrous material supplied per unit time, in accordance with the rotation / movement period of the capture / accumulation recess, an absorbent element is obtained having a part in which the surface density of the fibrous material is relatively high and a part in which the surface density of the fibrous material is relatively low.

[0055]

{2}

A method of manufacturing absorbent elements according to paragraph {1}, in which a uniform suction force is created on the entire lower surface of the recess for trapping / accumulation.

{3}

A method of manufacturing absorbent elements according to paragraph {1} or {2}, in which:

the fibrous material to be supplied to the rotary drum in a dispersed and air-suspended state is obtained by feeding sheet material representing fibrous material into a fiberizing machine; and

the amount of fibrous material supplied per unit time to the rotating drum in a dispersed and air-suspended state is periodically changed by changing the amount of sheet material supplied per unit time to the fiberizing machine.

{four}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {3}, in which the amount of fibrous material supplied per unit time to the channel is periodically changed by periodically changing the speed of the feed roller for supplying material, and thereby periodically changing the speed feeding the sheet material, which is a fibrous material, into a fiberizing machine.

{5}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {4}, in which the mass of fibrous material that reaches the outer peripheral surface of the rotating drum is periodically changed by

periodically changing the mass of the fibrous material supplied to the channel by means of the control unit for the supplied quantity in accordance with the sequence in which

the step of supplying a relatively small amount of fibrous material to the channel and

the step of supplying a relatively large amount of fibrous material to the channel

are repeated alternately, and

continuous supply of fibrous material while changing the feed amount.

[0056]

{6}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {5}, in which the mass of fibrous material that reaches the outer peripheral surface of the rotating drum is periodically changed by periodically changing the mass of the fibrous material in accordance with the sequence in which

a step of not supplying fibrous material to the channel and

the stage of feeding the fibrous material into the channel

are repeated alternately.

{7}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {6}, wherein the servomotor is used as a drive motor for the feed roller.

{8}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {7}, wherein the part in which the surface density of the fibrous material is relatively high and the part in which the surface density of the fibrous material is relatively low are formed in the absorbent element, which is obtained by discharging from a recess for collection / accumulation, by forming in a cluster provided by accumulation in a recess for trapping / accumulation, a part in which the amount accumulated in loknistogo material is small, and the part at which the accumulated amount of fibrous material is large.

{9}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {8}, in which a part with a high surface density, in which the surface density of the fibrous material is relatively high, is formed on the side of one end of the recess for capture / accumulation, which corresponds to the front end in the direction rotations, and a part with a low surface density, in which the surface density of the fibrous material is relatively low, form on the side of the other end of the recess for capture / accumulation, which The appropriate rear end in the direction of rotation.

{10}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {9}, wherein when transporting an absorbent element by means of a vacuum conveyor or a conveyor belt that serves as a conveyance means, the longitudinal direction of the absorbent element extends along the conveying direction, and the end of the absorbent element, having a part with high surface density, oriented to the side located further downstream in the direction of transportation.

[0057]

{eleven}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {10}, in which the absorbent element includes a part with a high surface density having a relatively high surface density, and a part with a low surface density having a relatively low surface density.

{12}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {11}, in which the ratio of the length of the channel hole, determined in the direction along the circumference of the drum, to the length of the recess for capture / accumulation, determined in the direction along the circumference of the drum, is preferably 2.0 or less, more preferably 1.5 or less, and preferably more than 0, more preferably 0.1 or more.

[0058]

{13}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {12}, in which parts (parts with a high surface density) in which the surface density of the fibrous material is relatively high, and parts (parts with a low surface density) in which the fibrous material is relatively low, form a wave-like shape on the outer peripheral surface of the rotating drum.

{fourteen}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {13}, wherein in the absorbent element, the ratio of surface density in the part in which the surface density of the fibrous material is highest to the surface density in the part in which the surface density of the fibrous material is the lowest is preferably 1.5 or more, more preferably 2 or more, and preferably 30 or less.

{fifteen}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {14}, wherein in the absorbent element, the surface density in the part in which the surface density of the fibrous material is highest is preferably 100 g / m ² or more, and preferably 3000 g / m ² or less.

{16}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {15}, in which:

all of the fibrous material or part of the fibrous material is preferably a cellulosic fiber; and

the proportion of cellulosic fiber in the fibrous material is preferably from 50 to 100% by mass., more preferably from 80 to 100% by mass., even more preferably 100% by mass.

{17}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {16}, wherein an absorbent element including a water-absorbing polymer is obtained by supplying a water-absorbing polymer to an air stream that carries fibrous material.

{eighteen}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {17}, in which by supplying a water-absorbing polymer with a constant feed quantity per unit time to the air stream that carries the fibrous material, the absorbent element, which includes a larger amount of water-absorbing polymer in the part in which the surface density of the fibrous material is relatively high than the part in which the surface density of the fibrous material is relatively low is obtained as absorbent item.

[0059]

{19}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {18}, wherein one type or combination of two or more types selected from sodium polyacrylate, a copolymer of acrylic acid and vinyl alcohol, a crosslinked sodium polyacrylate, is grafted as a water-absorbing polymer a copolymer of starch and acrylic acid, a copolymer of isobutylene and maleic anhydride and their saponification products, and polyaspartic acid.

{twenty}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {19}, in which:

a shutter is provided directly behind the chopper; and

the amount of fibrous material fed into the channel is periodically changed by opening / closing the shutter.

{21}

A method of manufacturing absorbent elements according to any one of paragraphs {1} - {20}, in which:

the lower surface of the capture / accumulation recess is provided with a first suction zone having a large fraction of the cross-section, and a second suction zone having a smaller fraction of the cross-section than the first suction zone; and

provide the accumulation of fibrous material both in the first suction zone and in the second suction zone.

{22}

A method of manufacturing absorbent elements according to any one of paragraphs {1} - {21}, in which:

an absorbent element is used as an absorbent element of an absorbent article; and

Absorbent article is an article used to absorb liquid released from the human body.

{23}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {22}, wherein the absorbent article is a disposable diaper, sanitary napkin, urological napkin or panty liner for daily use.

{24}

A method of manufacturing absorbent elements according to any one of paragraphs {1} to {23}, wherein when using the absorbent element in a disposable diaper, the absorbent element is used by incorporating it into the absorbent article so that a portion of the absorbent element having a high surface density is located on the abdomen side (front side) and the part with low surface density will be located on the back (back side).

{25}

Absorbent element containing

fibrous material and

water-absorbing polymer, while:

each of the surface density of the fibrous material and the surface density of the water-absorbing polymer varies along the longitudinal direction of the absorbent element;

in the longitudinal direction of the absorbent element, the part in which the surface density of the fibrous material is the highest coincides with the part in which the surface density of the water-absorbing polymer is the highest; and

the uneven distribution coefficient, which is the ratio between the surface density in the part in which the surface density is the highest, and the surface density in the part in which the surface density is the lowest, differs for the fibrous material and the water-absorbing polymer.

{26}

The absorbent element according to paragraph {25}, wherein the uneven distribution coefficient for the fibrous material is greater than the uneven distribution coefficient for the water-absorbing polymer.

{27}

The absorbent element according to paragraph {25} or {26}, in which the surface density of the fibrous material smoothly changes in the longitudinal direction of the absorbent element.

[0060]

{28}

A device for manufacturing absorbent elements, comprising:

a rotating drum having a plurality of pick-up / storage recesses formed on its outer peripheral surface at predetermined intervals;

a channel that provides the supply of fibrous material as the material of the absorbent element in a dispersed and air-suspended state to the outer peripheral surface of the rotating drum;

a fibrous material supply module that feeds fibrous material into the channel; and

unloading means, which provides the output of the accumulation, which is formed as a result of the accumulation of fibrous material in the recess for capture / accumulation, from the recess for capture / accumulation in the form of an absorbent element, while:

the manufacturing apparatus enables the manufacture of absorbent elements, wherein each individual absorbent element has a part in which the surface density of the fibrous material is relatively high, and a part in which the surface density of the fibrous material is relatively low, due to a change in the amount of fibrous material supplied per unit time per channel; and

The manufacturing device comprises a feed quantity control unit that determines a state of uneven distribution of the fibrous material in the absorbent element or accumulation and which, based on the determined uneven distribution state, provides a change in the amount of fibrous material supplied to the channel by the fiber supply module.

[0061]

{29}

The device for manufacturing absorbent elements according to paragraph {28}, in which the ratio of the length of the channel hole, which is determined in the direction along the circumference of the drum, which opens from the side of the rotating drum, to the length of the catch / accumulation recess, which is determined in the direction along the drum circumference, is preferably 2.0 or less.

{thirty}

A device for manufacturing absorbent elements according to paragraph {28} or {29}, in which the feed quantity control unit changes the supplied amount of fibrous material to produce an absorbent element in which the uneven distribution of the fibrous material coincides with the uneven distribution of the fibrous material previously stored in the memory device.

{31}

A device for manufacturing absorbent elements according to any one of paragraphs {28} to {30}, wherein the surface displacement measuring device, image processing, or capacitive sensor is used to determine an uneven distribution of the fibrous material in the absorbent element or cluster.

{32}

A device for the manufacture of absorbent elements according to any one of paragraphs { 1 } to {31}, in which

rotating drum includes

a cylindrical drum body and

an outer peripheral element, which is arranged to be superposed on the outer peripheral part of the drum body and which forms the outer peripheral surface of the rotating drum;

the outer peripheral element has in its outer peripheral part

porous plate and

the plate forming the contour, which is fixed in the state of its imposition from the outer surface of the porous plate; and

the bottom surface of the capture / accumulation recess is formed by a porous plate.

[0062]

{33}

A device for manufacturing absorbent elements according to paragraph {32}, wherein the porous plate is an air-permeable plate that provides movement of the air flow generated by suction from the side of the drum body from the outside of the rotating drum; which holds the material of the absorbent element carried by the air flow without causing the penetration of the material of the absorbent element through it, and which allows only air to pass through it.

{34}

A device for the manufacture of absorbent elements according to any one of paragraphs {28} - {33}, in which:

the channel extends from the feed module of the fibrous material to the rotating drum;

the fibrous material supply module includes a chopper as a fiberizing machine;

the sheet material, which is a fibrous material, is introduced into the shredder by a roller for feeding material; and

the fibrous material obtained by dividing into fibers by means of a chopper is fed into the channel.

{35}

A device for the manufacture of absorbent elements according to paragraph {34}, in which the feed module of the fibrous material includes:

two feed rollers that feed the sheet material into the shredder; and

a drive motor that drives and feeds the rollers.

{36}

The device for manufacturing absorbent elements according to paragraph {35}, in which the amount of fibrous material supplied per unit time to the channel increases with increasing speed of the drive electric motor, and the amount of fibrous material supplied per unit time to the channel decreases with decreasing speed of the drive electric motor.

{37}

A device for the manufacture of absorbent elements according to any one of paragraphs {28} - {36}, in which the control unit for the supplied quantity includes:

a computer having a display device and an input device;

an interface that electrically connects a computer and another device; and

a given program installed on a computer.

[0063]

{38}

A device for manufacturing absorbent elements according to any one of paragraphs {34} to {37}, further comprising a computer, wherein the computer controls the amount of sheet material supplied to the shredder by controlling the rotation of the drive motor by providing a control signal to the drive motor and thereby controlling the amount fibrous material fed into the channel.

{39}

A device for manufacturing absorbent elements according to any one of paragraphs {28} to {38}, further comprising:

a mechanism for producing a continuous absorbent element by closing the upper and lower surfaces of the absorbent elements, discharged from the respective recesses for capture / accumulation, covering sheet; and

a cutting device that cuts a continuous absorbent element into absorbent elements, each of which has a length that allows it to be used in a separate absorbent article.

{40}

A device for manufacturing absorbent elements according to any one of paragraphs {34} to {39}, in which the feed quantity control unit synchronizes the period of change in the feed rate of the sheet material into the shredder with the period during which the recess for trapping / accumulation passes through the portion covered by the channel .

{41}

A device for manufacturing absorbent elements according to any one of paragraphs {28} to {40}, wherein the dispersion tube for supplying a water-absorbing polymer, which is another type of absorbent material, into the channel is provided for the channel between the rotary drum and the fiber material supply module.

Examples

[0064]

The invention is described with further details below in accordance with its Examples. However, the scope of the invention is not limited by the Examples below.

[0065]

{Example 1}

The absorbent element was manufactured by using the device illustrated in FIG. Wood pulp was used as the sheet material 31A, and the feed amount was changed, as illustrated in FIG. 3 (a), to produce an absorbent member 3 having a part in which the surface density of the fibrous material is high and a part in which the surface the density is low, as illustrated in FIG. During the manufacture of the absorbent element 3, a uniform suction force was created in the entire area of the lower surface of the recess for trapping / accumulation. No water-absorbing polymer 32 was filed.

{Examples 2-5 and Comparative Examples 1-3}

Absorbent elements were made as in Example 1, except that the shape of the channel 4 next to the rotating drum 2 was changed, as indicated in the line "Channel shape" in Table 1, and the length of the recess to be detected in the direction along the circumference of the drum / accumulation was changed as shown in Table 1. The length of the recess for collecting / accumulating in the direction along the circumference of the drum corresponds to the length of the absorbent element made, which is determined in the longitudinal direction. In Comparative Examples 1-3, wood pulp was introduced into the shredder at a constant speed, and the amount supplied to the channel was not changed.

Forms 1-4 of the channels indicated in the column "Channel shape" in Table 1 are as follows:

Form 1: The form illustrated in figure 1; channel hole length: 940 mm.

Form 2: The form illustrated in FIG. 6 (a); channel hole length: 520 mm.

Form 3: The form illustrated in FIG. 6 (b); channel hole length: 346 mm.

Form 4: The form illustrated in FIG. 6 (c); channel hole length: 173 mm.

The manufacturing speed in Examples 1-4 and Comparative Examples 1-3 was 10 m / min. Only in Example 5, the manufacture was carried out at speeds of 10, 50, 100 and 150 m / min, and the evaluation result shown in Table 1 shows the average value for the four speed modes. The manufacturing speed is the peripheral speed of the rotating drum and the transportation speed of the conveyors 7, 7A.

[0066]

[Table 1]

Example Comparative Example one 2 3 four 5 one 2 3 Channel shape Form 1 Form 2 Form 2 Form 3 Form 4 Form 2 Form 3 Form 4 The length a of the channel hole, determined in the direction along the circumference of the drum (mm) 940 520 520 346 173 520 346 173 The length b of the recess for capture / accumulation, determined in the direction along the circumference of the drum (mm) 667 667 333 333 333 333 333 333 Uneven distribution coefficient for fibrous material 3.0 5,4 2,5 2.0 2.6 1,1 1,2 1,2

[0067]

{Grade}

For each of the absorbent elements obtained in Examples 1-5 and Comparative Examples 1-3, the ratio between the surface density of the part in which the surface density of the fibrous material was the highest and the surface density of the part in which the surface density of the fibrous material was the lowest, (hereinafter also referred to as the "uneven distribution coefficient") was determined in accordance with the aforementioned method and is shown in Table 1.

[0068]

In the absorbent elements obtained in Examples 1-5, which are embodiments of the invention, the uneven distribution coefficient was 1.5 or more, and the absorbent elements included a part in which the surface density of the fibrous material is the highest, and a part in which the surface density of the fibrous material is the lowest. On the other hand, in the absorbent elements obtained in Comparative Examples 1-3, the uneven distribution coefficient was 1.2 or less.

[0069]

In addition, for Examples 2-5, the results of determining the surface density at intervals of 30 mm along the longitudinal direction of each absorbent element, which corresponds to the direction of transportation during manufacture, are shown in Fig.7. Fig. 7 does not show the result for one absorbent element, but shows the result of continuous measurement of a plurality of absorbent elements, the successively formed absorbent elements being considered as continuous, so that the separated section at the end of one absorbent element, rearward in the longitudinal direction, and the separated section at the end the next absorbent element, the front in the longitudinal direction, are adjacent to ensure compliance with figure 3 (b). The measurement was carried out for three to four separate absorbent elements under the assumption that the length of each absorbent element was 333 mm. The length of the last separated portion on the side back in the conveying direction (that is, the portion that corresponds to both the 3F portion and the 3G portion in the absorbent member 3 illustrated in FIG. 5) was 33 mm. The interval shown by the arrow in FIG. 7 is an interval corresponding to one absorbent element.

[0070]

In addition, to assess the smoothness of the change in surface density, the degree of change in surface density was determined at intervals of 30 mm, and the frequency distribution is shown in Fig. 8. The degree of change in surface density was determined by using the difference in surface densities of the adjacent separated sections and the average surface density of one absorbent element. When considering FIG. 5 as an example, differences for parts were sequentially calculated, such as the difference for parts 3A and 3B, the difference for parts 3B and 3C, and so on, and the value obtained by dividing each difference by the average surface density was determined as the degree changes in surface density. In cases where the difference in surface densities was a negative value, its absolute value was considered as the degree of change in surface density. When the measurement errors were eliminated, the degree of change in surface density was 35% / 30 mm or less.

In cases where the maximum value of the degree of change in surface density was 35% / 30 mm or less when examining the degree of change in the surface density of the fibrous material at intervals of 30 mm along the longitudinal direction of the absorbent element, it was considered that in this absorbent element "surface density of the fibrous material changed smoothly ”in the longitudinal direction (one direction). A numerical value on the horizontal axis of the graph shown in FIG. 8 means that the interval indicated by a given numerical value is an interval that is greater than a value that is 5 percentage points less than a given numerical value and equal to or less than a given numerical value. For example, the interval for which the number 35 is shown as a numerical value on the horizontal axis of the graph for Example 5 is an interval in which the degree of change in surface density is greater than 30% and less than or equal to 35%, and this means that within the measured area there was one part, the degree of change in surface density in which was within this interval.

[0071]

{Examples 6 and 7}

The absorbent element was made as in Example 3 or 4, except that the water-absorbing polymer 32 was continuously supplied from the dispersion tube 55 during the manufacture of the absorbent element.

{Grade 1}

For each of the absorbent elements obtained in Examples 6 and 7, a relationship was determined between the surface density of the polymer in the part in which the surface density of the fibrous material was the highest and the surface density of the polymer in the part in which the surface density of the fibrous material was the lowest, ( hereinafter also referred to as the "second coefficient of uneven distribution for the polymer"). The results are shown in Table 2

[0072]

[Table 2]

Example 6 7 Channel shape Form 2 Form 3 The length a of the channel hole, determined in the direction along the circumference of the drum (mm) 520 346 The length b of the recess for capture / accumulation, determined in the direction along the circumference of the drum (mm) 333 333 Uneven distribution coefficient for fibrous material 2,4 1.8 The second coefficient of uneven distribution for the polymer 2.7 3.3

[0073]

The results in Table 2 show that, according to the method of the invention, an absorbent element can be obtained in which the water-absorbing polymer is distributed unevenly, even without having to carry out means for changing the supplied amount, for the device for supplying the water-absorbing polymer 32.

[0074]

{Grade 2}

For each of the absorbent elements obtained in Examples 6 and 7, the surface density of the fibrous material and the surface density of the water-absorbing polymer were determined at 30 mm intervals along the longitudinal direction of the absorbent element, which corresponds to the direction of transportation during manufacture. The results are shown in Fig.9. The degree of change in the surface density of the fibrous material and the degree of change in the surface density of the water-absorbing polymer was determined in accordance with the same method as the above method for determining the degree of change in the surface density of the fibrous material. Figure 10 shows the degree of change in surface density and frequency distribution separately for the fibrous material and the water-absorbing polymer.

The surface density of the fibrous material and the surface density of the water-absorbing polymer in each part separated at 30 mm intervals were determined as follows.

First, the total surface density of the fibrous material and the water-absorbing polymer was determined without distinguishing between the fibrous material and the water-absorbing polymer. After that, the image of the water-absorbing polymer in grayscale was obtained by means of a device with soft x-ray radiation, intended for imaging (EMT-J from Softex, Co., Ltd.). The surface density of the water-absorbing polymer was determined based on the degree of dark in the image in grayscale and the calibration curve of the surface density of the water-absorbing polymer, which was determined separately. The surface density of the fibrous material was determined by subtracting the surface density of the water-absorbing polymer from the total surface density of the fibrous material and the water-absorbing polymer.

[0075]

The results in Fig. 9 show that in Examples 6 and 7, the phase of the uneven distribution of the fibrous material coincided with the phase of the uneven distribution of the water-absorbing polymer. More specifically, in a graph in which the horizontal axis shows the longitudinal position of the absorbent element and the vertical axis shows surface density, the positions of the vertices and troughs on the curve for the fibrous material substantially coincide with the positions of the vertices and troughs on the curve for the water-absorbing polymer. In addition, the phase shift between the fibrous material and the water-absorbing polymer was one quarter of a period or less with respect to the length of the absorbent element (defined in the direction along the circumference of the drum, the length b of the capture / accumulation recess shown in Table 2). The degree of change in surface density was 50% / 30 mm or less.

[0076]

More specifically, as illustrated in FIG. 9, in both Examples 6 and 7, each of the surface density of the fibrous material and the surface density of the water-absorbing polymer varies along the longitudinal direction of the absorbent element within an interval corresponding to one absorbent element having a length of 333 mm.

In Example 6, within the interval corresponding to one absorbent element, the part in which the surface density of the fibrous material is the highest is the part located at a distance of 450-480 mm from the reference position corresponding to 0 mm, and the part in which the surface the density of the water-absorbing polymer is the highest, it is a part located at a distance of 390-420 mm from the reference position corresponding to 0 mm. The difference (in absolute value) in the location is 60, which is determined by subtracting 420 from 480, and less than one quarter of the length (333 mm) of the absorbent element. In Example 7, within the interval corresponding to one absorbent element, the part in which the surface density of the fibrous material is the highest is the part located at a distance of 480-510 mm from the reference position corresponding to 0 mm, and the part in which the surface the density of the water-absorbing polymer is the highest, is a part located at a distance of 420-450 mm from the reference position corresponding to 0 mm. The difference (in absolute value) in the location is 60, which is determined by subtracting 450 from 510, and less than one quarter of the length (333 mm) of the absorbent element.

It is believed that when the difference (in absolute value) in the location between the part in which the surface density of the fibrous material is the highest and the part in which the surface density of the water-absorbing polymer is the highest is equal to or less than one quarter of the length of the absorbent element in the longitudinal direction, the part in which the surface density of the fibrous material is the highest, and the part in which the surface density of the water-absorbing polymer is the highest, coincide with each other in longitudinal m direction of the absorbent element. In the absorbent element made in accordance with the invention and the absorbent element in accordance with the invention, when sequentially separating the absorbent element at intervals of 30 mm from one end in the longitudinal direction, it is preferable that the part in which the surface density of the fibrous material is the highest and the part in of which the surface density of the water-absorbing polymer is the highest, represented the same part or represented neighboring parts, or represented two parts at hydrochloric or two parts located therebetween, and more preferably they represent the same part or the neighboring parts, or two portions with one portion extending therebetween.

[0077]

In the absorbent element made in accordance with the invention and the absorbent element in accordance with the invention in calculating the uneven distribution coefficient, which is the ratio between the surface density (the highest surface density) in the part in which the surface density is the highest and the surface density ( the lowest surface density) in the part in which the surface density is the lowest (i.e. the ratio of the highest surface density to the most low surface density), for each of the fibrous material and the water-absorbing polymer, it is preferable that the uneven distribution coefficient be different for the fibrous material and the water-absorbing polymer for reasons related to the water absorption characteristic and for reasons related to the strength of the absorbent element, it is preferable that the coefficient the uneven distribution for the fibrous material was greater than the uneven distribution coefficient for the water-absorbing polymer pa

[0078]

{Example 11}

An absorbent element was manufactured using the device illustrated in FIG. 11. The wood pulp was used as the sheet material 31A, and the amount supplied to the shredder 51 was changed, as illustrated in FIG. 12 (a), to produce an absorbent member 3 having a part in which the surface density of the fibrous material is high, and the part in which the surface density is low, as illustrated in FIG. During the manufacture of the absorbent element 3, a uniform suction force was created in the entire area of the lower surface of the recess for trapping / accumulation. No water-absorbing polymer 32 was filed. In addition, during manufacture, the condition of uneven distribution of the fibrous material in the absorbent element 3 was monitored by using a surface displacement measuring device. The uneven distribution of the fibrous material has always been stable.

{Examples 12-15 and Comparative Examples 11-13}

Absorbent elements were made as in Example 11, except that the shape of the channel 4 next to the rotating drum 2 was changed, as indicated in the line "Channel shape" in Table 3, and the length of the recess to be detected in the direction along the circumference of the drum / accumulation was changed as shown in Table 3. The length of the recess for collecting / accumulating in the direction along the circumference of the drum corresponds to the length of the absorbent element made, determined in the longitudinal direction. In Comparative Examples 11-13, a sheet of wood pulp was fed to the chopper 51 always at a constant speed. “Yes” in the column “Regulation of the amount of pulp supplied” means that the supplied amount of wood pulp sheet was periodically changed.

Forms 1-4 of the channels indicated in the column "Channel shape" in Table 3 are as follows:

Form 1: The form illustrated in FIG. 11; channel hole length: 940 mm.

Form 2: The form illustrated in FIG. 6 (a); channel hole length: 520 mm.

Form 3: The form illustrated in FIG. 6 (b); channel hole length: 346 mm.

Form 4: The form illustrated in FIG. 6 (c); channel hole length: 173 mm.

[0079]

[Table 3]

Example Comparative Example eleven 12 13 fourteen fifteen eleven 12 13 Channel shape Form 1 Form 2 Form 2 Form 3 Form 4 Form 2 Form 3 Form 4 The length a of the channel hole, determined in the direction along the circumference of the drum (mm) 940 520 520 346 173 520 346 173 The length b of the recess for capture / accumulation, determined in the direction along the circumference of the drum (mm) 667 667 333 333 333 333 333 333 Ratio (a / b) 1.4 0.8 1,6 1,0 0.5 1,6 1,0 0.5 Regulation of the amount of pulp supplied Yes Yes Yes Yes Yes No No No Uneven distribution coefficient for fibrous material 3.0 6.8 2,4 1.8 2,8 1,1 1,2 1,2

[0080]

{Control Examples 11-14}

Absorbent elements were made as in Example 11, except that the shape of the channel 4 next to the rotating drum 2 was changed as indicated in the line “Channel shape” in Table 4, and the length of the recess for catching in the direction along the circumference of the drum / accumulation was changed as shown in Table 4. In Control Examples 11-14, the amount of pulp supplied was controlled, but the ratio of the length of the channel bore determined in the direction along the circumference of the drum, which opens from the side of rotation drum, to the length b of the recess for capture / accumulation, determined in the direction along the circumference of the drum, was more than 3.

[0081]

[Table 4]

Control Example eleven 12 13 fourteen Channel shape Form 1 Form 1 Form 2 Form 2 The length a of the channel hole, determined in the direction along the circumference of the drum (mm) 940 940 520 520 The length b of the recess for capture / accumulation, determined in the direction along the circumference of the drum (mm) 167 67 167 67 Ratio (a / b) 5,6 14.0 3,1 7.8 Regulation of the amount of pulp supplied Yes Yes Yes Yes Uneven distribution coefficient for fibrous material 1,1 1,1 1,2 1,1

[0082]

{Grade}

For each of the absorbent elements obtained in Examples 11-15, Comparative Examples 11-13 and Control Examples 11-14, the ratio between the surface density of the part in which the surface density of the fibrous material was the highest and the surface density of the part in which the surface density the fibrous material was the lowest, (hereinafter also referred to as the "uneven distribution coefficient") was determined in accordance with the above method and is shown in Tables 3 and 4.

[0083]

In the absorbent elements obtained in Examples 11-15, which are embodiments of the invention, the uneven distribution coefficient was 1.5 or more, and the absorbent elements included a part in which the surface density of the fibrous material is the highest, and a part in which the surface density of the fibrous material is the lowest. On the other hand, in the absorbent elements obtained in Comparative Examples 11-13, the uneven distribution coefficient was 1.2 or less, and the surface density was substantially constant.

Industrial applicability

[0084]

According to the manufacturing method of absorbent elements according to the invention, it is easy to manufacture an absorbent element having a part in which the surface density of the fibrous material is relatively high and a part in which the surface density of the fibrous material is relatively low, simply by changing the amount of fibrous material supplied to unit of time.

[0085]

According to the design of the device for manufacturing absorbent elements according to the invention, it is possible to produce an absorbent element in which a large amount of material of the absorbent element will be unevenly distributed in a predetermined part, and it is also possible to continuously produce such absorbent elements in a stable manner.

Claims (73)

1. A method of manufacturing absorbent elements, including: supplying fibrous material in a dispersed and air-suspended state to a rotating drum having a catch / accumulation recess formed on its outer peripheral surface, and ensuring the accumulation of fibrous material in the recess for capture / accumulation by suction to obtain an absorbent element having a given shape, wherein by periodically changing the amount of fibrous material supplied per unit time, in accordance with the rotation / movement period of the capture / accumulation recess, an absorbent element is obtained having a part in which the surface density of the fibrous material is relatively high and a part in which the surface density fibrous material is relatively low. 2. The method according to claim 1, in which a uniform suction force is created on the entire lower surface of the recess for trapping / accumulation. 3. The method according to claim 1, in which: the fibrous material to be supplied to the rotary drum in a dispersed and air-suspended state is obtained by feeding sheet material representing fibrous material into a fiberizing machine; and the amount of fibrous material supplied per unit time to the rotating drum in a dispersed and air-suspended state is periodically changed by changing the amount of sheet material supplied per unit time to the fiberizing machine. 4. The method according to claim 1, in which the amount of fibrous material supplied per unit time to the channel is periodically changed by periodically changing the rotational speed of the feed roller for supplying material, and thereby periodically changing the feed speed of the sheet material, which is a fibrous material into a fiber separation machine. 5. The method according to claim 1, in which the mass of fibrous material that reaches the outer peripheral surface of the rotating drum is periodically changed by periodically changing the mass of fibrous material supplied to the channel by the feed amount control unit in accordance with a sequence in which the step of supplying a relatively small amount of fibrous material to the channel and the step of supplying a relatively large amount of fibrous material to the channel are repeated alternately, and continuous supply of fibrous material while changing the feed amount. 6. The method according to claim 1, in which the mass of fibrous material that reaches the outer peripheral surface of the rotating drum is periodically changed by periodically changing the mass of fibrous material in accordance with the sequence in which the step of not supplying fibrous material to the channel and the step of supplying fibrous material to the channel are repeated alternately. 7. The method according to claim 1, in which the servomotor is used as a drive motor for the feed roller, designed to supply material. 8. The method according to claim 1, in which the part with a high surface density, in which the surface density of the fibrous material is relatively high, is formed on the side of one end of the recess for capture / accumulation, which corresponds to the front end in the direction of rotation, and part with a low surface density in which the surface density of the fibrous material is relatively low, is formed on the side of the other end of the capture / accumulation recess, which corresponds to the rear end in the direction of rotation I am. 9. The method according to claim 1, in which when transporting the absorbent element by means of a vacuum conveyor or belt conveyor, which serves as a means of transportation, the longitudinal direction of the absorbent element extends along the conveying direction, and the end of the absorbent element having a part with high surface density is oriented to the side downstream in the direction of transportation. 10. The method according to claim 1, in which the ratio of the length of the channel opening, determined in the direction along the circumference of the drum, to the length of the recess for trapping / accumulation, determined in the direction along the circumference of the drum, is greater than 0 and is up to 2.0 or less. 11. The method according to claim 1, in which parts with a high surface density, in which the surface density of the fibrous material is relatively high, and parts with a low surface density, in which the surface density of the fibrous material is relatively low, are formed in waves on the outer peripheral surface of the rotating drum. 12. The method according to claim 1, in which in the absorbent element the ratio of the surface density in the part in which the surface density of the fibrous material is highest to the surface density in the part in which the surface density of the fibrous material is from 1.5 to 30 . 13. The method according to claim 1, in which in the absorbent element the surface density in the part in which the surface density of the fibrous material is the highest is from 100 to 3000 g / m ² . 14. The method according to claim 1, in which: all fibrous material or part of the fibrous material is cellulosic fiber; and the proportion of cellulose fiber in the fibrous material is from 50 to 100 wt.%. 15. The method according to claim 1, in which the absorbent element comprising a water-absorbing polymer is obtained by supplying a water-absorbing polymer to the air stream that carries the fibrous material. 16. The method according to claim 1, in which by supplying a water-absorbing polymer with a constant feed quantity per unit time to the air stream that carries the fibrous material, an absorbent element, which includes a larger amount of water-absorbing polymer in the part in which the surface density of the fibrous material is relatively high than in the part in which the surface density of the fibrous material is relatively low, is obtained as an absorbent element. 17. The method according to claim 1, in which: a shutter is provided directly behind the chopper; and the amount of fibrous material fed into the channel is periodically changed by opening / closing the shutter. 18. The method according to claim 1, in which: the lower surface of the capture / accumulation recess is provided with a first suction zone having a large fraction of the cross-section, and a second suction zone having a smaller fraction of the cross-section than the first suction zone; and provide the accumulation of fibrous material both in the first suction zone and in the second suction zone. 19. The method according to claim 1, in which: an absorbent element is used as an absorbent element of an absorbent article; and Absorbent article is an article used to absorb liquid released from the human body. 20. The method according to claim 1, in which the absorbent product is a disposable diaper, sanitary pad, urological pad or panty liner for daily use. 21. The method according to claim 1, in which when using the absorbent element in a disposable diaper, the absorbent element is used by incorporating it into the absorbent article so that the high absorbent portion of the absorbent element is located on the abdomen (front side) and the low part surface density will be located on the back (back side). 22. A device for the manufacture of absorbent elements, containing: a rotating drum having a plurality of pick-up / storage recesses formed on its outer peripheral surface at predetermined intervals; a channel that provides the supply of fibrous material as the material of the absorbent element in a dispersed and air-suspended state to the outer peripheral surface of the rotating drum; a fibrous material supply module that feeds fibrous material into the channel; and unloading means, which provides the output of the accumulation resulting from the accumulation of fibrous material in the recess for capture / accumulation from the recess for capture / accumulation in the form of an absorbent element, wherein the manufacturing apparatus enables the manufacture of absorbent elements, wherein each individual absorbent element has a part in which the surface density of the fibrous material is relatively high and a part in which the surface density of the fibrous material is relatively low due to a change in the amount of fibrous material supplied per unit time per channel; and The manufacturing device comprises a feed quantity control unit that determines a state of uneven distribution of the fibrous material in the absorbent element or accumulation and which, based on the determined uneven distribution state, provides a change in the amount of fibrous material supplied to the channel by the fiber supply module. 23. The device according to item 22, in which the ratio of the length of the channel hole, which is determined in the direction along the circumference of the drum, that opens from the side of the rotating drum, to the length of the capture / accumulation recess, which is determined in the direction along the circumference of the drum, is 2.0 or less. 24. The device according to item 22, in which the control unit feed quantity changes the supplied amount of fibrous material for the manufacture of an absorbent element, in which the uneven distribution of the fibrous material coincides with the uneven distribution of the fibrous material previously recorded in the storage device. 25. The device according to item 22, in which a device for measuring surface displacement, image processing or a capacitive sensor is used to determine the condition of the uneven distribution of fibrous material in the absorbent element or accumulation. 26. The device according to item 22, in which: rotating drum includes: a cylindrical drum body and an outer peripheral element, which is arranged to be superposed on the outer peripheral part of the drum body and which forms the outer peripheral surface of the rotating drum; wherein the outer peripheral element has a porous plate in its outer peripheral part and the plate forming the contour, which is fixed in the state of its imposition from the outer surface of the porous plate; and the bottom surface of the capture / accumulation recess is formed by a porous plate. 27. The device according to p, in which the porous plate is an air-permeable plate, which provides movement of the air flow generated by suction from the side of the drum body, from the outer side of the rotating drum; wherein said porous plate holds the material of the absorbent element carried by the air flow without causing the penetration of the material of the absorbent element through it, and which allows only air to pass through it. 28. The device according to item 22, in which: the channel extends from the feed module of the fibrous material to the rotating drum; the fibrous material supply module includes a chopper as a fiberizing machine; the sheet material, which is a fibrous material, is introduced into the shredder by a roller for feeding material; and the fibrous material obtained by dividing into fibers by means of a chopper is fed into the channel. 29. The device according to p, in which the feed module of the fibrous material includes: two feed rollers that feed the sheet material into the shredder; and a drive motor that drives and feeds the rollers. 30. The device according to clause 29, in which the amount of fibrous material supplied per unit time to the channel increases with increasing frequency of rotation of the drive motor, and the amount of fibrous material supplied per unit of time to the channel decreases with decreasing frequency of rotation of the drive motor. 31. The device according to clause 29, further comprising a computer, wherein the computer controls the amount of sheet material supplied to the shredder by controlling the rotation of the drive motor by providing a control signal to the drive motor and thereby controlling the amount of fibrous material supplied to the channel. 32. The device according to p. 28, in which the control unit for the supplied quantity synchronizes the period of change in the feed rate of the sheet material into the shredder with the period during which the recess for capture / accumulation passes through the part closed by the channel. 33. The device according to item 22, further comprising: a mechanism for producing a continuous absorbent element by closing the upper and lower surfaces of the absorbent elements, discharged from the respective recesses for capture / accumulation, covering sheet; and a cutting device that cuts a continuous absorbent element into absorbent elements, each of which has a length that allows it to be used in a separate absorbent article. 34. The device according to item 22, in which the control unit for the supplied quantity includes: a computer having a display device and an input device; an interface that electrically connects a computer and another device; and a given program installed on a computer. 35. The device according to item 22, in which the dispersing pipe for supplying a water-absorbing polymer, which is another type of material of the absorbent element, into the channel is provided for the channel between the rotating drum and the module for supplying fibrous material.

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