JP2018089178A - Method for producing absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for producing an absorber which can produce the absorber having absorber materials unevenly distributed at desired positions, and can stably and continuously produce the absorber.SOLUTION: A fiber materials 31 obtained by defibrating a material sheet 31A in a defibrating machine 51 is supplied by an airstream to a rotational drum 2 having an outer peripheral surface on which collection recesses are formed. The fiber materials 31 are sucked and deposited in the collection recesses 22 to be shaped into a predefined shape in the collection recesses 22, the deposited material is then released from the recesses to obtain an absorber 3. By periodically changing a rotational speed of the rotational drum 2, as the absorber 3, a fiber deposited body is obtained having a portion with a relatively-large basis weight and a portion with a relatively-small basis weight of the fiber material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing an absorbent body.

  As an apparatus for manufacturing absorbent articles for absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads, a rotating drum having a concave portion for accumulation is provided on the outer peripheral surface, and pulp and the like are absorbed on the outer peripheral surface while rotating the rotating drum. The body material is supplied in a scattered state, and the absorber material is deposited in the accumulation recess by suction from the bottom surface of the accumulation recess composed of a porous member in which a large number of suction holes are formed. 2. Description of the Related Art Absorber manufacturing apparatuses are known in which a deposit formed into a predetermined shape is released from the inside to obtain an absorber. The absorbent body is used as an absorbent body for absorbent articles as it is or after being coated with a cover sheet such as paper or a breathable nonwoven fabric.

As such an apparatus for manufacturing an absorber, various apparatuses for manufacturing an absorber in which the distribution of the absorber material is not uniform in the plane direction have been proposed.
For example, in Patent Document 1, a first suction region having a high opening area ratio and a second suction region having a lower opening area ratio than the first suction region are provided on the bottom surface of the concave portion for accumulation, and the absorption capacity is partially increased. An apparatus for manufacturing an absorber having a highly designed portion has been proposed (see Patent Document 1).
In addition, the applicant of the present invention has a relatively high basis weight of the fiber material by periodically changing the amount of the fiber material supplied in a scattered state to the rotating drum having an accumulation recess formed on the outer peripheral surface. The method of obtaining the absorber which has a part and a part with relatively low basic weight of a fiber material was proposed (refer patent document 2).

JP 2004-65930 A Japanese Patent Laid-Open No. 2006-116860

  The absorber manufacturing apparatus described in Patent Document 1 is capable of partially adjusting the accumulation amount of the absorber material in the concave portion for accumulation and manufacturing an absorber in which the basis weight of the absorber material is partially different. However, when changing the specifications such as the area ratio of the areas having different basis weights, it was necessary to modify the accumulation recesses themselves, which required a lot of labor.

According to the method described in Patent Document 2, a portion in which the basis weight of the fiber material is relatively high and a basis weight of the fiber material are relatively low by simply changing the supply amount of the fiber material per unit time. There is an advantage that an absorber having a portion can be manufactured.
However, when the inventors rapidly increase or decrease the supply speed of the raw material sheet as a raw material of the fiber material to the defibrator for the purpose of manufacturing an absorbent body having a plurality of regions having a large basis weight difference, the raw material It has been found that the fiber defibration state may become insufficient when the sheet supply rate is high. In addition, when a motor such as a servo motor is used as the drive source of the raw material sheet feeding device, the design of the basis weight difference is restricted due to the load applied to the motor at high speed rotation and the low response at high speed rotation. .

  The subject of this invention is providing the manufacturing method of the absorber which can solve the fault which the prior art mentioned above has.

  In the present invention, a fiber material obtained by defibrating a raw material sheet with a defibrator is supplied on a rotating drum having an accumulation recess formed on the outer peripheral surface and supplied on an air stream, and the supplied fiber material is sucked. Depositing in the accumulation recess and releasing the deposit formed in a predetermined shape from the accumulation recess to obtain an absorber, wherein the rotational speed of the rotating drum is periodically A method of manufacturing an absorbent body, in which a fiber deposit having a portion having a relatively high basis weight of the fiber material and a portion having a relatively low basis weight of the fiber material is obtained as the absorbent body. It is to provide.

  According to the method for manufacturing an absorbent body of the present invention, the fiber material has a portion with a relatively high basis weight and a portion with a relatively low basis weight of the fiber material, and the fibrillation state of the configured fiber material is entirely A good absorbent body can be produced over a long period of time.

FIG. 1 is a schematic view showing an embodiment of an absorbent body production apparatus preferably used for carrying out the absorbent body production method of the present invention. FIG. 2 is an exploded perspective view showing the structure of the concave portion for accumulation in the manufacturing apparatus shown in FIG. FIG. 3 (a) is a graph showing how to change the rotational speed of the rotating drum in a preferred embodiment, FIG. 3 (b) is a graph showing the manufacturing cycle of the absorber, and FIG. 3 (c). These are explanatory drawings, such as the length of the drum peripheral direction of a duct opening part. FIG. 4 is a perspective view showing an example of an absorbent body obtained by the present invention. FIG. 5 is an explanatory diagram of a method for measuring the basis weight of the portion having the lowest basis weight of the fiber material and the portion having the highest basis weight of the fiber material.

Hereinafter, the present invention will be described based on preferred embodiments thereof.
First, an absorbent body manufacturing apparatus preferably used in an embodiment of the absorbent body manufacturing method of the present invention will be described with reference to FIG. The absorbent body manufacturing apparatus 1 shown in FIG. 1 is also an embodiment of the absorbent body manufacturing apparatus of the present invention.
As shown in FIG. 1, the absorbent body manufacturing apparatus 1 shown in FIG. 1 has a rotating drum 2 having a plurality of accumulation recesses 22 formed on the outer peripheral surface at predetermined intervals, and an outer peripheral surface 2 f of the rotating drum 2. In the duct 4 for supplying the fiber material 31 and the water-absorbing polymer 32 as the absorber material in a scattered state, the fiber material supply unit 5 for supplying the fiber material 31 into the duct 4, and the accumulation recess 22 A release air blow device 10 for releasing the deposit produced by depositing the fiber material 31 and the water-absorbing polymer 32 as the absorbent body 3 from the concave portion 22 for accumulation, and a first disposed below the rotary drum 2. And a vacuum conveyor 7 as a conveying means.

The rotary drum 2 includes a cylindrical drum main body 20 made of a metal rigid body, and an outer peripheral member 21 that is arranged on the outer peripheral portion of the drum main body 20 and forms the outer peripheral surface 2 f of the rotary drum 2. Has been. The outer peripheral member 21 receives power from a motor (not shown) such as a motor and rotates around the horizontal axis in the direction of arrow R, while the drum body 20 is fixed and does not rotate.
As shown in FIG. 2, the outer peripheral member 21 has a porous plate 27 (porous member) and a pattern forming plate 28 that is fixed on the outer surface 27 a side of the porous plate 27, as shown in FIG. 2. . The bottom surface of the accumulation recess 22 is formed from a porous plate 27.

  The pattern forming plate 28 has an outer surface 28a that forms the outer peripheral surface 2f of the rotating drum 2 and an inner surface 28b that faces the rotating shaft side of the rotating drum 2, and an accumulation recess is provided between the outer surface 28a and the inner surface 28b. 22 has a space portion 280 having a shape corresponding to the three-dimensional shape in 22. The outline 22L of the space 280 coincides with the outline of the accumulation recess 22. As the pattern forming plate 28, for example, a plate formed by machining a metal or resin plate such as stainless steel or aluminum to form an opening (a space portion 280 having a shape corresponding to the three-dimensional shape in the accumulation recess 22), Alternatively, a plate in which the opening is integrally formed using a mold, a punched or etched plate, a superposition of these plates, or the like can be used.

The porous plate 27 transmits the air flow generated by the suction from the drum body 20 side to the outside of the rotating drum 2, holds the absorber material carried on the air flow without passing it, and the air It is a breathable plate that only allows it to pass through. The porous plate 27 is formed with a plurality of (multiple) suction holes (pores) penetrating the plate 27 in the thickness direction with a uniform distribution over the entire plate 27, and the accumulation recess 22 is a rotating drum. While passing through the space A maintained at a negative pressure in 2, the suction hole functions as an airflow vent. The porous plate 27 in the absorbent body manufacturing apparatus 1 has a constant aperture ratio over the entire region, and a suction force control plate or the like that partially varies the suction force is disposed below the porous plate 27. Not. That is, the accumulation recess 22 in the absorbent body manufacturing apparatus 1 generates a uniform suction force on the entire bottom surface.
As the porous plate 27, for example, a metal or resin mesh plate, or a metal or resin plate formed with a plurality of (many) pores by etching or punching can be used.

  As shown in FIG. 1, the drum body 20 includes a plurality of mutually independent spaces A, B, C, partitioned by a partition plate 20p provided from the central axis side of the rotary drum 2 toward the outer peripheral surface 2f. D. An intake fan (not shown) is connected to the central shaft portion 222 of the drum body 20 so that the pressure in the partitioned spaces A to D in the rotary drum 2 can be adjusted by driving the intake fan. Thus, in the absorber manufacturing apparatus 1, the suction force in the area of the space A located in the area where the outer peripheral surface 2f is covered with the duct 4 is stronger than the suction force in the areas of the spaces BD. Since the spaces C and D are regions including the transfer position of the absorber 3 in the accumulation recess 22 and the front and back thereof, zero pressure or positive pressure is preferable.

As shown in FIG. 1, the duct 4 extends from the fiber material supply unit 5 to the rotary drum 2, and the opening on the downstream side of the duct 4 is a space A in the rotary drum 2 that is maintained at a negative pressure. The outer peripheral surface 2f located above is covered.
The fiber material supply unit 5 includes a defibrating machine 51 and a raw material sheet supply device 6.
The defibrator 51 pulverizes a raw material sheet 31 </ b> A such as a pulp sheet to form a fiber material 31 that is a fibrous material such as pulp fiber, and the generated fiber material 31 is opened toward the inside of the duct 4. The material is supplied into the duct 4 from the material supply port.
The defibrating machine 51 includes a defibrating roll 51a and a casing 51b. The defibrating roll 51a has a large number of defibrating blades on its peripheral surface for defibrating by contacting the leading edge of the raw material sheet 31A. The defibrating roll 51a is supported by bearings at both ends of the rotating shaft protruding from the casing 51b, and power from a power source such as a motor is transmitted to the rotating shaft by an arbitrary power transmission means such as a gear or a belt. And is driven to rotate. The defibrating roll 51a is rotationally driven in one direction at a constant speed.

  The raw material sheet supply device 6 includes a known nip roll 61 and a drive motor 62, and the control unit 8 rotates the nip roll 61 with the drive motor 62 while the raw material sheet 31 </ b> A is sandwiched between the pair of nip rolls 61. The raw material sheet 31A is supplied to the defibrating machine 51 at a controlled speed.

  Between the rotating drum 2 and the fiber material supply unit 5 in the duct 4, a spray pipe 55 that supplies the duct 4 with a water-absorbing polymer 32, which is another kind of absorber material, is provided. An air flow that causes the absorbent material (fiber material 31 and water-absorbing polymer 32) to flow toward the outer peripheral surface 2f of the rotary drum 2 in the space in the duct 4 by the operation of the intake fan (not shown) of the rotary drum 2 Has come to occur.

  The holding belt 24 is an endless breathable or non-breathable belt, and is stretched over the roll 25, the roll 26, and other rolls (not shown), and is rotated along with the rotation of the rotary drum 2. When the pressing belt 24 is a breathable belt, it is preferable that the absorbent material (the fiber material 31 and the water-absorbing polymer 32) in the accumulation concave portion 22 is not allowed to pass therethrough. Even if the pressure in the space B is set to atmospheric pressure, the presser belt 24 can hold the deposit in the stacking recess 22 in the stacking recess 22 until it is transferred onto the vacuum conveyor 7.

  The vacuum conveyor 7 (conveying means) is disposed below the rotary drum 2 and is close to the outer peripheral surface 2f located in the space C where the rotary drum 2 is set to have a weak positive pressure or zero pressure (atmospheric pressure). Are arranged. The vacuum conveyor 7 has an endless breathable belt 73, a vacuum box 74 disposed at a position facing the outer peripheral surface 2f of the rotary drum 2 with the breathable belt 73 interposed therebetween, and a breathable belt 73 wound around the vacuum conveyor 7. A plurality of rolls 75 and 76 are provided. The plurality of rolls 75 and 76 are drive rolls in which at least one roll 75 is driven by a drive motor such as a servomotor. On the vacuum conveyor 7, a breathable coating sheet 35 made of thin paper (tissue paper) or non-woven fabric is introduced. This air-permeable covering sheet 35 is also a liquid-permeable covering sheet.

  The mold release air blow device 10 is a mold release means for releasing the deposit obtained by depositing the absorber material (the fiber material 31 and the water-absorbing polymer 32) in the stacking recess 22 from the stacking recess 22. Function as. The release air blow device 10 is disposed inside the outer peripheral member 21 in the space C, and the inner surface of a porous plate (porous member) that forms the bottom surface of the accumulation recess 22 on which the absorber material is deposited. Air can be blown from the side toward the outer surface 27a side, and release of the deposit from the accumulation recess 22 is promoted by the air.

As shown in FIG. 1, the absorber manufacturing apparatus 1 has a function of controlling the rotational speed of the rotary drum 2 and a function of controlling the amount of the fiber material 31 supplied from the fiber material supply unit 5 into the duct 4. A control unit 8 is provided. Although not shown in detail, the control unit 8 includes a computer including a display unit, an interface for electrically connecting the computer and other devices, a predetermined program incorporated in the computer, and the like.
The control unit 8 outputs a control signal to a drive motor (not shown) that drives the rotary drum 2 by the function of controlling the rotation speed of the rotary drum 2 to increase or decrease the rotation speed of the drive motor. The rotational speed of the rotating drum can be increased or decreased a plurality of times while the rotating drum 2 rotates once. The drive motor that drives the rotary drum 2 is preferably an electric motor, and more preferably a servo motor.

Further, the control unit 8 outputs a control signal to the drive motor 62 of the raw material sheet supply device 6 by the function of controlling the amount of the fiber material 31, and maintains the rotation speed of the drive motor 62 at a constant value. The supply speed of the sheet 31A to the defibrator 51 can be maintained at a constant speed.
Further, by switching the setting, the control signal for the drive motor 62 of the raw material sheet supply apparatus 6 can be changed to control the supply amount of the raw material sheet 31 </ b> A to the defibrating device 51 to change periodically. When the rotational speed of the drive motor 62 is increased, the supply amount of the raw material sheet 31A to the defibrator 51 is increased, and the supply amount of the fiber material per unit time in the duct 4 and the outer peripheral surface of the rotary drum 2 is increased. When the rotational speed is lowered, the supply amount of the raw material sheet 31A to the defibrator 51 is reduced, and the supply amount of the fiber material per unit time to the outer peripheral surface of the duct 4 and the rotary drum 2 is reduced. When changing the rotation speed of the drive motor 62, the drive motor is preferably an electric motor, more preferably a servo motor. The drive motor for driving the rotary drum 2 and the drive motor 62 of the raw material sheet supply device 6 and the control unit 8 are input according to the type of rotation control signal output from the control unit 8 and the type of motor. Known devices such as an output interface and a servo amplifier are arranged. The control unit 8 can use a programmable logic controller (PLC) or other similar device instead of a computer.

Further, the absorbent body manufacturing apparatus 1 includes a mechanism for covering the upper and lower surfaces of the absorbent body 3 released from the accumulation recess 22 with the covering sheets 35 and 36 to obtain the continuous absorbent body 30A. The covering sheet 36 covering the surface opposite to the covering sheet 35 supplied on the vacuum conveyor 7 in the absorbent body 3 is placed after the absorbent body 3 is placed at the center in the width direction on one side of the covering sheet 35. Further, both sides of the covering sheet 35 folded back to the other side may be used, or a covering sheet 36 different from the covering sheet 35 supplied onto the vacuum conveyor 7 may be used. As the covering sheet 36, a thin paper (tissue paper), a non-woven fabric, or the like can be used similarly to the covering sheet 35, and preferably has air permeability. This air-permeable covering sheet 36 is also a liquid-permeable covering sheet.
Moreover, the manufacturing apparatus 1 of an absorber cut | disconnects the absorber continuous body 30A into the absorber 30 of the length (henceforth length of one absorbent article) used for each absorbent article. A cutting device 9 is provided. As the cutting device 9, various known cutting means used for manufacturing absorbent articles and absorbent bodies can be used. For example, as shown in FIG. 1, a cutter roll 91 having a cutting blade 92 and its blade are received. It has the anvil roll 93, and what cuts the absorber continuous body 30A sequentially by a fixed period by rotation of both rolls can be used.

A method for continuously producing the absorbent body 3 using the above-described absorbent body production apparatus 1, that is, an embodiment of the absorbent body production method of the present invention will be described.
In order to manufacture the absorber 3 using the manufacturing apparatus 1 described above, the rotary drum 2 is rotated and the intake fan is operated to make the space A have a negative pressure. Further, the release air blow device 10, the vacuum conveyor 7 as the first conveying means, the belt conveyor 7 </ b> A as the second conveying means arranged adjacent to the vacuum conveyor 7, and the cutting device 9 are operated.
By the operation of the intake fan, a uniform suction force is generated over the entire bottom surface of the accumulation recess 22 located on the space A, and the air flowing in the duct 4 toward the outer peripheral surface of the rotary drum 2. A flow is generated.

  And if the raw material sheet supply apparatus 6 of the fiber material supply part 5 is operated and the raw material sheet 31A of the fiber material 31 is introduced into the defibrating machine 51, the fiber material 31 generated by defibrating by the defibrating machine 51 is generated in the duct 4. To be supplied. The fiber material 31 supplied into the duct 4 is in a scattered state, is carried on the air flow flowing through the duct 4, and is supplied toward the outer peripheral surface of the rotary drum 2.

In the manufacturing method of the present embodiment, as shown in FIG. 3A, the rotational speed of the drive motor that drives the rotary drum 2 is increased or decreased by the control function of the rotational speed of the rotary drum 2 of the control unit 8. In addition, the rotational speed (circumferential speed) of the rotating drum is increased or decreased a plurality of times during one rotation of the rotating drum 2. The number of times that the rotational speed of the rotating drum 2 is increased or decreased during one rotation of the rotating drum 2 is preferably the same as the number of accumulation recesses 22 provided in the rotating drum 2.
On the other hand, for the raw material sheet supply device 6, the control unit 8 maintains the rotational speed of the drive motor 62 at a constant value and supplies the raw material sheet 31 </ b> A to the defibrating device 51 at a constant speed. In that case, the fiber material 31 generated by defibration by the defibrator 51 is supplied to the duct 4 or the outer peripheral surface of the rotary drum 2 at a constant speed.

As shown in FIGS. 3 (a) and 3 (b), the mode in which the rotational speed of the rotating drum 2 is periodically changed includes a period in which the rotating speed of the rotating drum 2 is changed, and a manufacturing period T of the absorber. Are preferably matched. “Match” here means, as shown in FIGS. 3 (a) and 3 (b), one period for changing the rotation speed of the rotary drum 2 and one period for the manufacturing cycle T of the absorber. Means a one-to-one correspondence, and the phase may be shifted.
The manufacturing cycle T of the absorbent body is a desired time interval in which the absorbent body 30 having a length corresponding to one absorbent article having a configuration in which one absorbent body, preferably a fiber deposit body is coated with a coating sheet, is produced. For example, in the example shown in FIG. 1, it is a time interval for cutting the absorber continuous body 30 </ b> A by the cutting device 9, and the time required for one rotation of the cutter roll 91 of the cutting device 9 is determined by the cutter roll 91. This coincides with the quotient divided by the number of cutting blades 92 at different positions. In the absorbent article production line including the absorbent body production process, the absorbent article production cycle T is usually the same as the time interval at which individual absorbent articles are produced.
The rotational speed control pattern shown in FIG. 3 (a) is such that the step of rotating the rotary drum 2 at a relatively high speed and the step of rotating the rotary drum 2 at a relatively low speed are alternately performed. This is a repeated pattern, and the rotating drum 2 is continuously rotated at different speeds. Instead of this, the rotating drum 2 may be intermittently rotated in a pattern in which the step of rotating the rotating drum 2 and the step of not rotating the rotating drum 2 are repeated alternately.

  Further, the mode in which the rotational speed of the rotating drum 2 is periodically changed is that the rotational speed of the rotating drum 2 is changed and the accumulation recess 22 is covered with the duct 4 as shown in FIG. It is preferable to match the period of passing through the specific position P2 of the portion.

According to the manufacturing method of the present embodiment, by periodically changing the rotation speed of the rotary drum 2, the deposition amount of the fibrous material 31 and the portion of the fibrous material 31 that are deposited on the accumulation concave portion 22 are reduced. A portion having a large amount of deposition can be formed, and in each absorbent body obtained by releasing from the concave portion 22 for accumulation, the portion having a relatively high basis weight of the fiber material and the basis weight of the fiber material are relatively Lower portion is formed. FIG. 4 is a perspective view showing an example of the absorbent body 3 manufactured by the manufacturing apparatus 1 of the present embodiment.
In the absorbent body 3 shown in FIG. 4, a high basis weight portion 33 having a relatively high basis weight of the fiber material is formed on the one end 3 a side corresponding to the rotation direction front end f of the accumulation recess 22, and the accumulation recess 22. A low basis weight portion 34 having a relatively low basis weight of the fiber material is formed on the other end 3b side corresponding to the rear end r in the rotation direction. The absorber 3 has a longitudinal direction 3X corresponding to the circumferential direction of the rotary drum 2 and a width direction 3Y orthogonal to the longitudinal direction. When the absorbent body 3 is transported by a vacuum conveyor 7 as a first transport means and a belt conveyor 7A as a second transport means, the longitudinal direction 3X extends along the transport direction X as shown in FIG. The one end 3a side having the high basis weight portion 33 is directed to the downstream side in the transport direction.
As shown in FIG. 1, the absorbent body 3 thus obtained is coated with the covering sheets 35 and 36 to form an absorbent body continuous body 30 </ b> A, and then cut into a predetermined length by the cutting device 9. The absorbent body 30 covered with the covering sheet is incorporated into an absorbent article such as a disposable diaper.

In this way, according to the manufacturing method of the present embodiment, an absorber in which a large amount of absorber material is unevenly distributed at a desired site in one absorber simply by periodically changing the rotation speed of the rotary drum 2. Can be manufactured. Moreover, since there is no need to change the raw material sheet feeding device, the fiber defibrating state, which is likely to occur when the supply speed of the raw material sheet to the defibrator is rapidly increased or decreased, is less likely to occur. It is also possible to produce an absorbent body having a fine state throughout.
Moreover, basically, the uneven distribution state of the fiber material can be changed to some extent only by periodically changing the rotation speed of the rotary drum 2, so that a complicated operation such as changing the shape of the duct is required. In addition, it is possible to cope with a design change in the uneven distribution state of the fiber material relatively easily.

  The uneven distribution state of the fiber material in the manufactured absorbent body 3 is monitored by a monitoring device capable of measuring or estimating the uneven distribution state such as a surface displacement meter. If the uneven distribution state is not a desired state, the rotating drum 2 The fiber material is unevenly distributed in a desired state by adjusting the phase between the period of changing the rotation speed of the sheet and the period in which the accumulation recess 22 passes through the arbitrarily defined specific position P2 of the portion covered with the duct 4 It is preferable to modify so as to obtain an absorbed body.

In the manufacturing method of the present embodiment, the deposit in the accumulation concave portion 22 of the rotary drum 2 is released on the vacuum conveyor 7 as the first conveying means. , And fluctuating in synchronization with the rotational speed of the rotating drum 2. More specifically, at the closest portion of the rotary drum 2 and the vacuum conveyor 7, the moving speed of the outer peripheral surface of the rotary drum 2 and the moving speed of the transfer surface of the vacuum conveyor 7 are always consistent, The mold is released on the vacuum conveyor 7 moving at the same speed as the outer peripheral surface of the rotary drum 2 over the entire length in the conveying direction. Thereby, when moving a deposit to the vacuum conveyor 7 from the rotating drum 2, it can prevent that the deposit itself and the uneven distribution state of a fiber material collapse | crumble. The expression of releasing on the first conveying means includes a case where the covering sheet 35 is introduced on the first conveying means and the deposit is released on the covering sheet 35.
On the other hand, on the downstream side of the vacuum conveyor 7 serving as the first transport means, a belt conveyor 7A serving as the second transport means having a constant transport speed is arranged, and the absorbent body 3 released from the vacuum conveyor 7 is released. Is transferred to a belt conveyor 7A having a constant conveying speed. Thereby, it can be made not to give the influence which changed the rotational speed of the rotating drum 2 periodically to the subsequent process, for example, the disposable diaper containing the absorber which changed the specification of the distribution state of fiber material Etc. can be manufactured while suppressing modification of the manufacturing equipment as a whole and an increase in manufacturing costs.

In the absorbent body manufacturing apparatus shown in FIG. 1, the vacuum conveyor 7 is used as the first transport means and the belt conveyor 7A is used as the second transport means. However, as the first and second transport means, Any transporting means capable of transporting the deposit or the absorber 3 can be used. Moreover, it is preferable that the belt conveyor 7A as a 2nd conveyance means is also a vacuum conveyor.
In order to change the conveying speed of the first conveying means in synchronization with the change in the rotating speed of the rotating drum 2, the absorbent body manufacturing apparatus 1 shown in FIG. It has a function of controlling the rotation of a drive motor (not shown) that drives the roll 75.
Note that the transport speed of the second transport means is set to be higher than the average transport speed of the first transport means, and the absorber 3 or the second transport means is transferred during transfer from the first transport means to the second transport means. It is preferable that the interval between the absorbent bodies 30 each having the core portion made of the absorbent body 3 is increased.

  The absorbent body 30 or the absorbent body 30 having the core portion made of the absorbent body 3 is preferably used as an absorbent body of an absorbent article. The absorbent article is mainly used to absorb and retain body fluids excreted from the body such as urine and menstrual blood. Absorbent articles include, for example, disposable diapers, sanitary napkins, incontinence pads, panty liners, etc., but are not limited to these, and widely include articles used to absorb liquid discharged from the human body. To do.

Moreover, the absorber 3 in which the absorbent body 3 or the core portion is composed of the absorbent body 3 is composed of the high basis weight portion 33 having a relatively high basis weight and the low basis weight portion 34 having a relatively low basis weight. And the deposit amount of the absorber material is partially different. As an absorber used for a disposable diaper, it is used by being incorporated in an absorbent article so that the high basis weight portion 33 is located on the front side of the wearer and the low basis weight portion 34 is located on the back side of the wearer. It is preferable in that the performance of the absorber is maximized.
Moreover, having the high basic weight part and low basic weight part from which the basic weight of a fiber material differs in the absorber 3 is easy to ensure a high absorption capacity | capacitance in a required part, for example, However, Absorption of the part inferior to necessity It is also preferable from the viewpoint of reducing the capacity and reducing the amount of the raw material used as a whole. In addition, the absorber 3 can also be used as an absorber of an absorbent article, without coat | covering with the coating sheets 35 and 36. FIG.

  As shown in FIG. 4, the absorbent body 3 to be manufactured has a high basis weight portion 33 in which the basis weight of the fiber material is relatively high on the front end side in the rotation direction of the rotary drum 2, and a basis weight of the fiber material on the rear end side. The basis weight is not limited to the low basis weight portion 34, and the high basis weight portion 33 in which the basis weight of the fiber material is relatively high and the low basis weight portion 34 in which the basis weight of the fiber material is relatively low. May be manufactured in any form, and the low basis weight of the fiber material is relatively low on both sides of the high basis weight portion with a relatively high basis weight of the fiber material Absorber in which a high basis weight part with a relatively high basis weight of the fiber material is formed on both sides of the absorbent body in which the part is formed or a low basis weight part with a relatively low basis weight of the fiber material The body may be manufactured.

From the viewpoint of connecting the change in the rotational speed of the rotating drum 2 to the difference in the basis weight of the fiber material in the absorbent body 3, the length of the duct opening in the drum circumferential direction is relative to the length of the accumulation recess 22 in the drum circumferential direction. The ratio is preferably 3 or less, more preferably 2.5 or less, and still more preferably 2 or less. Further, from the viewpoint of the magnitude relationship between the deposition rate of the fiber material and the pneumatic transport rate of the same material in the duct 4, the ratio is preferably more than 1.5, and more preferably 2 or more.
As shown in FIG. 3C, the length of the duct opening in the drum circumferential direction is the length between both ends 4f and 4r of the opening 4e on the rotating drum side of the duct 4 in the direction along the circumferential direction of the rotating drum. It is measured along the outer peripheral surface of the rotating drum. The length of the accumulation recess 22 in the drum circumferential direction is the length between both ends f and r of the accumulation recess 22 in the direction along the circumferential direction of the rotating drum, and is measured along the outer peripheral surface of the rotation drum.

In the absorbent body produced in the present invention, the ratio of the basis weight of the portion with the highest basis weight of the fiber material to the basis weight of the portion with the lowest basis weight of the fiber material is preferably 1.5 or more, more preferably 2 or more, preferably 30 or less. Moreover, the basis weight of the lowest basis weight of the fiber material is preferably 100 g / m ² or more and 3000 g / m ² or less from the viewpoint of the absorber strength.
The basis weight of the portion having the highest basis weight of the fiber material and the portion having the lowest basis weight of the fiber material is determined as follows. That is, as shown in FIG. 5, a straight line C along the width direction 3Y is drawn at an interval of 30 mm from one end 3a in the longitudinal direction 3X of the absorbent body 3, and the absorbent body 3 is divided into a plurality of portions 3A to 3F with the straight line C as a boundary. And the area and the mass of the fiber material contained are determined for each of the divided portions. Then, the basis weight is calculated from the calculated mass and area, the basis weight of the divided portion with the highest calculated basis weight is set as the basis weight of the portion with the highest basis weight of the fiber material, and the calculated basis weight is the lowest division. Let the basic weight of a part be the basic weight of the part with the lowest basic weight of a fiber material. In addition, as shown with a dotted line in FIG. 5, when the absorber 3 has a portion 3G extending from the last drawn straight line Ce with a length of less than 30 mm, the portion 3G is not divided on the straight line Ce. As a part of the previous part 3F, the basis weight of the part 3F is calculated. The one end 3a in the longitudinal direction 3X of the absorbent body 3 is the one end closer to the abdomen side (front side) of the wearer in the front-rear direction when the absorbent article is an absorbent body. When the relationship between the wearer's front and rear is unknown, the end corresponding to the rotational direction front end f of the concave portion 22 for accumulation is defined as one end, and when the relationship is unknown, any one end in the longitudinal direction is defined as one end.

  In the above-described embodiment, the rotational speed of the rotating drum 2 is periodically changed, while the supply amount per unit time of the raw material sheet 31 </ b> A to the defibrating machine 51 is constant, and the fiber material with respect to the outer peripheral surface of the rotating drum 2 is fixed. Although the supply amount is constant, instead of this, the rotational speed of the rotating drum 2 is periodically changed, and the supply amount per unit time of the raw material sheet 31A to the defibrating device 51 is periodically changed to rotate the rotating drum. The amount of the fiber material supplied to the outer peripheral surface of 2 may be changed periodically. Thereby, manufacture of the absorber with a large basis weight difference with the part with the lowest basis weight of the part with the lowest basis weight of a fiber material, etc. become easy.

In the method of the present invention, in addition to supplying the fiber material 31 to the duct 4, it is also preferable to supply the water-absorbing polymer 32. The water-absorbing polymer 32 is supplied from, for example, the spray tube 55 described above, and supplied into the air stream that conveys the fiber material 31.
The water-absorbing polymer 32 can also be continuously supplied with a constant supply amount (mass) per unit time. Even if the water-absorbing polymer 32 is continuously supplied, the water-absorbing polymer 32 is more in the portion of the air flow conveying the fiber material 31 in the portion where the concentration of the fiber material is high than in the portion where the concentration is low. Since 32 is entangled, a relatively large amount is included. Therefore, as the absorbent body 3, an absorbent body having more water-absorbing polymer in a portion where the basis weight of the fiber material is relatively high than in a portion where the basis weight of the fiber material is relatively low is obtained. According to the manufacturing method or manufacturing apparatus of the present embodiment, an absorbent body in which the water-absorbing polymer is unevenly distributed can be obtained without providing means for changing the supply amount in the water-absorbing polymer 32 supply apparatus.

  The water-absorbing polymer 32 can also be supplied by periodically changing the supply amount (mass) per unit time. In that case, as with the supply of the fiber material, the step of supplying the water-absorbing polymer and the step of not supplying the water-absorbing polymer may be repeated in a pattern, or the step of supplying a relatively large amount of the water-absorbing polymer. And a pattern in which a relatively small amount of the water-absorbing polymer is supplied may be supplied. In either case, it is preferable to periodically change the supply amount of the water-absorbing polymer in accordance with the passage period of the accumulation recess. As a mode to match the passage period of the concave portion for accumulation, a large amount of water-absorbing polymer is deposited on a portion where the amount of fiber material is deposited, and a small amount of water-absorbing polymer is deposited or not deposited on a portion where the amount of fiber material is deposited is low. However, it is not limited to this. When the supply amount of the water-absorbing polymer is periodically changed, the apparatus for supplying the water-absorbing polymer may include a control unit that periodically changes the supply amount of the water-absorbing polymer per unit time with respect to the air flow. preferable. The control unit of the apparatus for supplying the water-absorbing polymer may also serve as the control unit 8 of the manufacturing apparatus 1 or may be provided separately from the control unit 8 of the manufacturing apparatus 1.

  The absorbent article typically includes a top sheet, a back sheet, and a liquid-retaining absorbent body disposed between both sheets. The upper and lower surfaces of the absorber may be covered with one or a plurality of covering sheets. The back sheet may or may not have water vapor permeability. The absorbent article may further include various members according to specific uses of the absorbent article. Such members are known to those skilled in the art. For example, when the absorbent article is applied to a disposable diaper or a sanitary napkin, a pair or two or more pairs of three-dimensional guards may be disposed on both sides in the longitudinal direction of the absorbent article that coincides with the wearer's longitudinal direction. it can.

  As the fiber material and the water-absorbing polymer used in the present invention, various materials conventionally used for absorbent bodies of absorbent articles such as sanitary napkins, panty liners, and disposable diapers can be used without particular limitation. For example, short fibers of cellulosic fibers such as pulp fibers, rayon fibers, and cotton fibers, and short fibers of synthetic fibers such as polyethylene are used. These fibers can be used alone or in combination of two or more. Moreover, it is preferable that the fiber material is entirely or partly pulp fiber, and the ratio of the pulp fiber in the fiber material is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, More preferably, it is 100 mass%. In addition to the fiber material, a deodorant or an antibacterial agent may be supplied into the duct as necessary. The water-absorbing polymer may or may not be supplied.

  Examples of water-absorbing polymers include sodium polyacrylate, (acrylic acid-vinyl alcohol) copolymer, cross-linked sodium polyacrylate, (starch-acrylic acid) graft copolymer, and (isobutylene-maleic anhydride) copolymer. Examples thereof include a polymer and a saponified product thereof, and polyaspartic acid. A fiber and a water absorbing polymer can be used individually by 1 type or in combination of 2 or more types.

As mentioned above, although the one embodiment of the manufacturing method and manufacturing apparatus of the absorber of this invention was demonstrated, this invention is not restrict | limited to embodiment mentioned above, Each can be changed suitably.
For example, instead of the surface displacement measuring instrument, image processing or a capacitance sensor can be used to measure the uneven distribution state of the fiber material of the manufactured absorber. In the image processing, for example, the basis weight amount of the fiber material can be determined based on the density of the absorber in the image captured by the imaging unit. The electrostatic capacity sensor is preferable because it is suitable for measuring insulators such as cellulose fibers such as pulp fibers, rayon fibers, and cotton fibers used as a material for absorbent articles, and synthetic fibers such as polyethylene.
Further, the concave portion for accumulation in the absorbent body manufacturing apparatus 1 shown in FIG. 1 generates a uniform suction force on the entire bottom surface, but is relatively lower than a region that generates a relatively high suction force on the bottom surface. An accumulation recess having a region that generates a suction force may be used. For example, the method of the present invention can be combined with the method described in Patent Document 1. That is, a first suction area having a high opening area ratio and a second suction area having a lower opening area ratio than the first suction area are provided on the bottom surface of the accumulation recess 22 and the fiber material is deposited on both the suction areas. You can also.
Moreover, you may manufacture the absorber which does not contain a water absorbing polymer, without supplying a water absorbing polymer, while supplying a fiber material to a duct.

DESCRIPTION OF SYMBOLS 1 Absorbent body manufacturing apparatus 2 Rotating drum 2f Outer peripheral surface 20 Drum body 21 Outer peripheral member 22 Concave portion for accumulation 3 Absorber 31 Fiber material 31A Raw material sheet 32 Water-absorbing polymer 33 High basis weight part 34 Low basis weight part 30 Having a covering sheet Absorber 4 Duct 4e Duct opening 5 Textile material supply part 51 Defibration machine 52 Raw material supply roller 53 Drive motor 10 Release air blow device 7 Vacuum conveyor (first conveying means)
7A Belt conveyor (second conveying means)
8 Control unit 9 Cutting device 91 Cutter roll 92 Cutting blade 93 Anvil roll 55 Water-absorbing polymer spray tube

Claims (5)

The fiber material obtained by defibrating the raw material sheet with a defibrator is supplied on a rotating drum having a concave portion for accumulation formed on the outer peripheral surface thereof on an air stream, and the supplied fiber material is sucked for the accumulation. A method of manufacturing an absorbent body, wherein the absorbent body is obtained by depositing in a concave portion and releasing a deposit formed in a predetermined shape from the concave portion for accumulation.
By periodically changing the rotational speed of the rotating drum, a fiber deposit body having a portion having a relatively high basis weight of the fiber material and a portion having a relatively low basis weight of the fiber material as the absorber. A method for producing an absorbent body.   A step of releasing the deposit on the first conveying means whose conveying speed fluctuates in synchronization with the rotating speed of the rotating drum, and then transferring the deposit to the second conveying means having a constant conveying speed; The manufacturing method of the absorber of Claim 1 which comprises.   The manufacturing method of the absorber of Claim 1 or 2 which makes the period which changes the rotational speed of the said rotating drum, and the manufacturing period of the said absorber correspond.   The manufacturing method of the absorber of any one of Claims 1-3 which changes the supply amount per unit time of the said raw material sheet with respect to the said fibrillator periodically.   The manufacturing method of the absorber of any one of Claims 1-4 which supply a water absorbing polymer in the air flow which conveys the said fiber material, and obtain the fiber deposit body containing a water absorbing polymer.

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