JP7598131B2 - Pattern Plate - Google Patents

Description

The present invention relates to a pattern plate used in an absorbent body manufacturing apparatus for absorbent articles such as disposable diapers.

Disposable diapers and sanitary napkins are examples of absorbent articles that absorb excretory fluids such as urine and menstrual blood. These absorbent articles have an absorbent body made by molding a fluid absorbent material containing pulp fibers and granular superabsorbent polymer (hereinafter also referred to as SAP) into a single sheet as a component for absorbing excretory fluids.

The absorbent body is produced by a manufacturing apparatus such as that shown in Patent Document 1 (JP Patent Publication No. 2014-100440). The schematic configuration of the manufacturing apparatus will now be described with reference to FIG. 5 in this application. The manufacturing apparatus 11 has a rotating drum 12. On the outer peripheral surface 12D of the rotating drum 12, a plurality of pattern plates 21 (described later) are arranged in parallel in the circumferential direction D so that the absorbent body P is formed.

Within the rotating drum 12, negative pressure compartment 12a, positive pressure compartment 12b and non-pressure compartment 12c are formed by partition walls that are fixed and do not follow the rotation of the rotating drum 12 and are set at a predetermined angle to the axis of the rotating drum 12.In addition, an intake and exhaust mechanism (not shown) is provided to draw in air in the negative pressure compartment 12a and exhaust air in the positive pressure compartment 12b.

In addition, a spray duct 13 is provided at a predetermined position in the circumferential direction D of the rotating drum 12, facing the negative pressure section 12a inside the rotating drum 12. This spray duct 13 sprays powdered absorbent material Z, which is a mixture of pulp fibers, SAP, etc., toward the outer circumferential surface 12D of the rotating drum 12 located in the negative pressure section 12a during rotation.

When passing through the area of the spray duct 13 (negative pressure section 12a) in the circumferential direction D of the rotating drum 12, the absorbent material Z is sucked in and deposited on the holes 21a of the pattern plate 21 described below by the intake air generated in the negative pressure section 12a and spraying from the spray duct 13.

Then, as the drum 12 passes through the area of the positive pressure section 12b downstream in the circumferential direction D of the negative pressure section 12a, the absorbent material Z that has been sucked in and accumulated is peeled off from the outer peripheral surface 12D by exhaust air, and the single-sheet absorbent P is transported further downstream to a process.

Figures 6 and 7 show the relationship between the rotating drum 12 and the pattern plate 21 provided on the circumferential surface of the rotating drum 12. Figure 6 is a schematic perspective view of the rotating drum 12 with a portion of the pattern plate 21 removed, and Figure 7 is an exploded perspective view showing the configuration of the pattern plate 21.

The pattern plate 21 has a surface plate 21A having a number of arc-shaped divisions corresponding to the curvature of the outer peripheral surface 12D of the rotating drum 12 and having a number of holes 21a formed therein, a reinforcing plate 21B having rod portions B1, B2 arranged in a framed lattice pattern and fixed against the inner peripheral surface of the surface plate 21A to provide backing and reinforcement from the inner peripheral surface (of the rotating drum 12) of the surface plate 21A, and a guide plate 21C which partially covers the surface plate 21A to expose the holes 21a of the surface plate 21A within the range of the planar shape of the desired absorbent body P.

Continuing with the example of Patent Document 1, in order to improve productivity, a negative pressure is generated in the negative pressure area 12a of the rotating drum 12, which rotates at high speed, to draw in outside air into the rotating drum 12, and high-pressure absorbent material Z is sprayed from the spray duct 13 toward the surface plate 21A of the pattern plate 21.

Repeated use of the pattern plate 21 causes the frame edge that defines (forms) the holes 21a of the surface plate 21A to wear away due to the spray pressure (impact) of the absorbent material Z, gradually losing the frame edge and causing damage to the surface plate 21A, such as opening a large hole with a continuous series of holes 21a. To prevent this damage to the surface plate 21A, a reinforcing plate 21B is provided in the pattern plate 21.

The reinforcing plate 21B may be configured in a lattice shape with rod sections B1 and B2 as shown in the figure, or may be made of a coarse wire mesh or a punched plate, but the common requirement is that it has a thickness and structure that will not bend as a whole even when subjected to an impact when the absorbent material Z is sprayed.

The surface plate 21A and the reinforcing plate 21B are usually integrated together. Integrating them together is generally achieved by, for example, stacking the surface plate 21A and the reinforcing plate 21B (and the guide plate 21C) and bolting their edges together, or by stacking the surface plate 21A and the reinforcing plate 21B and diffusion bonding them together.

However, bolting and diffusion bonding have their pros and cons. With bolting, if the surface plate 21A is damaged, only the surface plate 21A can be replaced. However, because the entire contact surface between the surface plate 21A and the reinforcing plate 21B is not bonded, the positive and negative pressures of the rotating drum 12 during use can cause the surface plate 21A to pulsate or flutter relative to the reinforcing plate 21B, causing the absorbent material Z to get between the surface plate 21A and the reinforcing plate 21B, causing the surface plate 21A to float from the reinforcing plate 21B, preventing the reinforcing plate 21B from being reinforced, and increasing the frequency of breakage.

With diffusion bonding, the entire contact surface between the award plate 21A and the reinforcing plate 21B is bonded, so there is no pulsation as occurs with the bolt fastening, making the frequency of breakage low. However, if the surface plate 21A is damaged, the entire plate, including the reinforcing body 21B, must be replaced, which increases the replacement costs. In addition, because high-temperature processing is used, the surface plate 21A becomes softened by annealing, making it more susceptible to breakage.

JP 2014-100440 A

The problem faced by the present invention is that conventional pattern plates are unable to achieve both easy replacement of the surface plate if it becomes damaged, and a low frequency of damage during use.

In order to solve the above-mentioned problems, the present invention provides a pattern plate used in a manufacturing device for manufacturing absorbent articles, the pattern plate comprising a surface plate having a plurality of holes formed therein, and a reinforcing plate laminated on the back surface of the surface plate and having a plurality of holes formed therein, the surface plate and the reinforcing plate being joined by projection welding between the opposing surfaces of the surface plate and the reinforcing plate, and a joining/peeling layer being formed which can be later peeled off by hand by an operator and which requires a force of 20 to 60 N when peeling .

According to the present invention, the bonding/peeling layer can be peeled off from the reinforcing plate if the surface plate is damaged, thus solving the problem of integrating the surface plate and reinforcing plate by conventional diffusion bonding. In addition, when used as a pattern plate, the opposing surfaces of the surface plate and reinforcing plate are bonded, which has the advantage of solving the problem of integrating the surface plate and reinforcing plate by conventional bolt fastening.

FIG. 2 is an exploded perspective view showing a pattern plate of the present invention. FIG. 2 is a partially enlarged perspective view showing a surface plate and a reinforcing plate of the pattern plate of the present invention. 1A and 1B show a pattern plate of the present invention, in which (a) is a partially enlarged view, and (b) is a cross-sectional view taken along line AA of (a). FIG. 2 is a diagram showing the relationship between a rotating drum and a pattern plate of the present invention. FIG. 1 is a diagram showing a schematic configuration of a conventional manufacturing apparatus. FIG. 1 is a diagram showing the relationship between a conventional rotating drum and a conventional pattern plate. FIG. 1 is a diagram showing a schematic configuration of a conventional pattern plate.

The present invention achieves the object of obtaining a pattern plate that is easily replaceable and has excellent durability by comprising a surface plate having a plurality of holes formed therein and a reinforcing plate that is laminated on the back surface of the surface plate and has a plurality of holes formed therein, the surface plate and the reinforcing plate being joined by projection welding between the opposing surfaces of the surface plate and the reinforcing plate, and forming a joining/peeling layer that can later be peeled off by hand by an operator and that requires a peeling force of 20 to 60 N.

Simply put, the bonding/peeling layer means a layer that can be attached and peeled off. Therefore, the bonding/peeling layer must be able to maintain a secure bonded state during use, be able to be peeled off if the surface plate is damaged, and not block any holes in the surface plate or the reinforcing plate.

In addition, in the present invention, in the above configuration, the bonding/peeling layer may require a force of 20 to 60 N when peeling the surface plate from the reinforcing plate. In other words, this 20 to 60 N is a level at which the bonding between the surface plate and the reinforcing plate is secure and the reinforcing plate can be easily peeled off. If the bonding/peeling layer is used with a force of less than 20 N, the bonding will be insufficient and the surface plate and the reinforcing plate may shift or peel off during use, while if the force is more than 60 N, peeling will be difficult and workability will decrease.

Furthermore, in the present invention, the reinforcing plate may be configured such that some holes in the surface plate are treated as unit hole groups and a rib is formed by connecting the non-hole portions of the unit hole groups. The rib in the reinforcing plate may be formed by connecting the non-hole portions of the unit hole groups of some holes in the surface plate as unit hole groups, for example, a total of 10 unit hole groups consisting of three in the upper row, four in the middle row, and three in the lower row, and the non-hole portions of the outer edges of the unit hole groups may be connected to form a rib.

In this way, the area surrounded by the ribs does not block the holes in the surface plate, and the ribs form holes (openings) that penetrate through the front and back of the reinforcing plate and are larger in diameter than the holes in the surface plate. This means that the reinforcing plate with the ribs formed on it improves the rigidity of the surface plate, and also makes it possible to remove the pattern plate from the rotating drum and reliably clean the back side of the reinforcing plate.

Furthermore, in the above-mentioned configuration, the present invention may be configured such that the reinforcing plate is made of a plurality of sheets stacked and integrated together. If there are concerns about the reinforcing surface of the reinforcing plate, multiple reinforcing plates may be stacked and integrated together.

There are no particular limitations on the method of stacking and integrating multiple reinforcing plates, but for example, diffusion bonding can be used to improve rigidity and achieve strong integration. This not only improves the rigidity of the entire pattern plate, but also prevents the holes in the surface plate from becoming deeper, so clogging can be suppressed even if the thickness is increased.

An embodiment of the present invention will be described with reference to Figures 1 to 3. Note that the overall configuration of the absorbent article manufacturing apparatus is not the point of the present invention and has been explained in the section on prior art, so its explanation will be omitted in this embodiment. Also, in this embodiment, the same reference numerals will be used for the same members as in Figures 5 and 6, and their explanation will be omitted.

The pattern plate 1 of the present invention is provided on the peripheral surface of a rotating drum 12 (in place of the pattern plate 21 in Figs. 5 and 6) in a manufacturing apparatus for manufacturing absorbent articles as shown in Fig. 5. A plurality of pattern plates 1 cover the outer peripheral surface 12D of the rotating drum 12, and each of the pattern plates is formed in an arc shape corresponding to the curvature of the number of divisions of the rotating drum 12.

As shown in FIG. 1, the pattern plate 1 has a surface layer 2 having a plurality of holes 2a formed therein, a reinforcing plate 3 laminated on the rear surface of the surface layer 2, and a guide plate 4 which partially covers the surface layer 2 to expose the holes 2a of the surface layer 2 within the planar shape range of the desired absorber P. In this example, for example, a projection welding layer 5 is formed as a joining/peeling layer between the opposing surfaces of the surface layer 2 and the reinforcing plate.

Considering clogging of the holes 2a with the absorber material Z, it is desirable for the surface plate 2 to be thin, and the material used is, for example, stainless steel, which has excellent corrosion resistance and appropriate rigidity. For example, in this example, the surface plate 2 is 0.3 mm thick, and circular holes 2a with a diameter of 0.45 mm are formed by etching.

In addition, the surface plate 2 has positioning holes (not shown) at its four corners, allowing it to be positioned with high precision relative to the reinforcing plate 3. Since the thin surface plate 2 can be used for the holes 2a, they can be etched to create the hole diameter and pitch according to the order.

The reinforcing plate 3 is made of a stainless steel plate that is the same size as the surface plate 2 and has positioning holes (not shown) formed at its four corners in the same positions as the surface plate 2A. In the same area as the surface plate 3, several holes 2a are formed as unit hole groups 2A, in this example, one in the center and five around it for a total of six holes 2a, by etching to form ribs 3A connecting the connecting parts 2b, which are the peripheral parts that form the holes 2a in the unit hole group 2A.

In this example, nine reinforcing plates 3 are stacked in this order from the outer periphery of the rotating drum 12, using their respective positioning holes to precisely align the ribs 3A of the upper and lower layers so that they do not shift, and the entire structure is diffusion bonded to form a single unit.

As mentioned above, in this example, the reinforcing plate 3 is made of a material such as stainless steel for reasons of durability and corrosion resistance, but the thickness of the plate does not need to be as thin as that of the surface plate 2, and it is sufficient if the plate is of the maximum thickness that can be etched into the rib 3A.

The area surrounded by the ribs 3A is roughly hexagonal (or lotus leaf shaped) and corresponds only to the connection portion 2b of the surface plate 2, does not block the hole 2a, and forms a roughly hexagonal hole (opening) that penetrates the front and back of the reinforcing plate 3 and is larger in diameter than the hole 2a of the surface plate 2 by the ribs 3A. The reinforcing plate 3 with the ribs 3A formed thereon reinforces the rigidity of the surface plate 2.

In addition, the multiple reinforcing plates 3 may all have the same rib 3A (opening) shape, or each or some of the reinforcing plates 3, or all of the reinforcing plates 3 may have a different rib 3A (opening) shape. In this case, however, the ribs 3A are configured so as not to block the openings of ribs 3A adjacent to each other in the stacking direction.

In this way, by stacking the reinforcing plate 3 toward the back side of the surface plate 2 so that the opening dimensions created by the ribs 3A are larger, the openings and holes 2a created by the ribs 3A are not blocked by the ribs 3A even when the thickness is increased, making it easy to clean the pattern plate.

The projection welding layer 5, which is the joining/peeling layer in this example formed between the back surface of the surface plate 2 and the surface of the reinforcing plate 3 facing the surface plate 2, refers to a layer interposed with a protrusion 5A formed by etching on the end face of a rib 3A, which is the surface of the reinforcing plate 3 facing the surface plate 2 of the reinforcing plate 3, as shown in Figure 3, for example.

When the surface plate 2 and the reinforcing plate 3 are stacked, electricity, for example 300 to 1500 A, is passed between the surface of the surface plate 2 and the back surface of the bottom layer of the reinforcing plate 3, causing the protrusion 5A to heat up due to electrical resistance, and the protrusion 5A is welded and joined to the surface plate 2 and the reinforcing plate 3. If the current value is lower than 300 A, the surface plate 2 may become displaced from the reinforcing plate 3 when the pattern plate 1 is in use, and if it is higher than 1500 A, it will be firmly welded and difficult to peel off.

The current value, as well as the planar area, pitch (number), and current flow time of the protrusions 5A are adjusted so that the force required to peel the surface plate 2 from the reinforcing plate 3 is 20 to 60 N. This force required to peel is the value measured with an Imada Co., Ltd. ZTS-5N digital force gauge using an Imada Co., Ltd. P90-200N 90 degree peel test fixture peel test system attachment in accordance with JIS C 5016: 1994 Flexible Printed Wiring Board Peel Test (90° Peel).

By forming the projection welding layer 5 so that the force required for peeling is 20 to 60 N, the surface plate 2 will not shift or even partially peel off from the reinforcing plate 3 when the pattern plate 1 is in use, and there is no problem in which the surface plate 2 is damaged and cannot be peeled off by hand when attempting to replace it.

The projection welding layer 5 employed as the joining/peeling layer in the above embodiment of the pattern plate 1 of the present invention is characterized in that it is a joining technique that is originally specialized for joining, i.e. does not assume peeling, but is used to join the surface plate 2 and the reinforcing plate 3 so that they can be peeled off by the worker. Therefore, the present invention is not particularly limited as long as it satisfies the conditions for reliable joining and later peeling off by the worker.

In the above, an example has been described in which a projection welding layer 5 is formed on the entire opposing surface between the surface plate 2 and the reinforcing plate 3, including the area not exposed from the guide plate 4 (the area hidden by the guide plate 4). However, it is also possible to configure the structure so that only the area exposed from the guide plate 4 is replaced.

When replacing only the area exposed from the guide plate 4, the surface plate 2 is divided into an area exposed from the guide plate 4 and an area not exposed, and in the area exposed from the guide plate 4, the hole 2a of the surface plate and the rib 3A of the reinforcing plate 3 are formed, and the projection welding layer 5 is interposed between them. This eliminates the need to remove the guide plate 4, making the work easier.

1 Pattern plate 2 Surface plate 2a Hole 3 Reinforcement plate 3A Rib 5 Projection welding layer (joining/peeling layer)

Claims (3)

The pattern plate is used in a manufacturing device for producing absorbent articles, and comprises a surface plate having a plurality of holes formed therein, and a reinforcing plate laminated on the back surface of the surface plate and having a plurality of holes formed therein, the surface plate and the reinforcing plate being joined by projection welding between opposing surfaces of the surface plate and the reinforcing plate, and a joining/peeling layer is formed between the opposing surfaces of the surface plate and the reinforcing plate which can be later peeled off by hand by an operator and which requires a force of 20 to 60 N when peeling . 2. The pattern plate according to claim 1, wherein said reinforcing plate is formed with ribs connecting non-hole portions of some holes of said surface plate into unit hole groups. 3. The pattern plate according to claim 1, wherein the reinforcing plate is a laminate of a plurality of sheets.

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