WO2020142009A2

WO2020142009A2 - Production system of partite core for absorbent articles

Info

Publication number: WO2020142009A2
Application number: PCT/TR2018/050947
Authority: WO
Inventors: Özlem ESEN; Çağla BEKTAŞ
Original assignee: Evyap Sabun Yag Gliserin Sanayi Ve Ticaret Anonim Sirketi
Priority date: 2018-12-31
Filing date: 2018-12-31
Publication date: 2020-07-09
Also published as: WO2020142009A3

Abstract

The present invention relates to a partite core production system (1) for absorbent articles (A) comprising a plurality of cylindrical rotary drums (2), at least one rotating unit for rotating the drums (2) from the center thereof, at least one superabsorbent polymer (SAP) feeding unit (3) and at least one pulp feeding unit (4) provided on the drum (2) for each drum (2), a mold (6) provided on the outer surface of each drum (2) to shape at least one absorbent layer (5), a vacuum unit for creating vacuum in the inner surface of the mold (6) and enabling the absorbent layer (5) to be held in the mold (6), at least one position measuring device for measuring the position of the mold (6), and a control unit which is adapted to create vacuum in the inner surface of the mold (6) by means of the vacuum unit upon receiving the information from the position measuring device that the mold (6) is at the first position where it is aligned with the superabsorbent polymer (SAP) feeding unit (3) and pulp feeding unit (4) and which is adapted to reduce or stop the said vacuum formation upon receiving the information that the mold (6) is at a selected second position.

Description

PRODUCTION SYSTEM OF PARTITE CORE FOR ABSORBENT

ARTICLES

Field of the Invention

The present invention relates to a production system of partite core for absorbent articles.

Background of the invention

Absorbent articles are products in the category of hygiene. Examples of absorbent diapers include baby diapers, pants, adult diapers and sanitary napkins (women’s hygiene products). A conventional absorbent article is basically comprised of four parts. There is a back sheet at the bottom, a core on the back sheet, an acquisition and distribution layer on the core and a top sheet on the acquisition and distribution layer. The top sheet is the layer that will contact the user’s body and it is the first layer that will contact the bodily wastes such as urine, blood and hard or soft stools.

The acquisition and distribution layer located under the top sheet is for absorbing the bodily fluids such as urine, blood and soft stool from the top sheet and distributing it on its own surface to ensure transmission thereof to the absorbent core provided on the back sheet.

The core is comprised of an absorbent layer which comprises a mixture of a superabsorbent polymer (SAP) and pulp and which is wrapped/coated with a fabric. The core is for retaining the bodily fluids transmitted from the acquisition and distribution layer. The bodily fluids pass through the said fabric and reach the absorbent layer and are retained therein.

The liquid impermeable back sheet is for preventing the body wastes from reaching the underwear. The core is typically adhered to the surface of the back sheet by means of an adhesive material.

Various problems may arise in the absorbent articles in the prior art. One of these problems arises from the inability of the superabsorbent polymer (SAP) and pulp mixture provided in the core to be adequately adjusted to provide the critical performance characteristics of the absorbent articles. The distribution and proportions of the superabsorbent polymer (SAP) and pulp in the mixture have a critical importance in absorption and retention of the bodily fluids and maintaining the integrity and function of the core layer that is exposed to the bodily fluids. Failure to prepare the mixture in appropriate proportions causes inability of certain parts of the core layer to absorb sufficient amount of bodily fluids or absorption of a more than required amount of the bodily fluids at certain regions. Failure to absorb sufficient amount of bodily fluids results in inability of the absorbent article to fulfill its function. Regional absorption of a more than required amount of bodily fluids results in excessive regional swelling of the absorbent layer. Excessive swelling of certain regions of the absorbent layer causes discomfort to the user and limits the freedom of movement of the user.

Another problem arises from the facts that the period of time the bodily fluids are transmitted to the absorbent layer is long and that they cannot be distributed along the surface of the absorbent layer. Because the said transmission time is long, the bodily fluids remain in interaction with the wearer's skin for a longer period of time. As a result of the long interaction period of time, skin disorders such as rashes, redness and irritation are frequently observed particularly in sensitive skins. In the case that the bodily fluids cannot be distributed throughout the surface of the absorbent layer, the bodily fluids accumulate intensely in the middle region of the absorbent layer. Due to the said fluid accumulation in the middle region, the superabsorbent polymer (SAP) particles swell excessively and turn into a gel. As liquid permeability/transmission cannot be achieved between the gelled superabsorbent polymer (SAP) particles, the bodily fluids cannot be distributed to the superabsorbent polymer (SAP) particles at the other regions of the absorbent layer (particularly the front and rear regions), and consequently the said other regions of the absorbent layer cannot be used. Upon movement of the users, the middle regions of the absorbent layer where the bodily fluids excessively accumulate and the other regions that remain dry are separated from each other due to the movements of the user, and lumps of agglomeration and sagging occur in the middle regions. As a result, leakage problems occur in the absorbent article.

Although the acquisition and distribution layer supports the distribution of the said bodily fluids throughout the surface of the absorbent layer, adequate distribution cannot be achieved. In the prior art, channels have been provided on the absorbent layer to support the distribution process. The bodily fluids are intended to be distributed to the front and rear parts of the absorbent layer with the help of the channels. However, although the time to absorb the fluid and the amount of wetness returned to the skin have been slightly improved in these absorbent articles with channels, the glues between the channels of the absorbent layer weaken over time under the effect of the body wastes and the distance between the channels increases due to the swelling of the superabsorbent polymer (SAP) particles. This in turn causes the absorbent layer to lose its channels and leads to deterioration of the integrity of the absorbent layer. In addition, in cases where the optimization of the superabsorbent polymer (SAP) and pulp is not well adjusted, the absorbent layer is excessively swollen and the fitting of the absorbent article to the body becomes difficult. As a result of this, the performance of the absorbent article is weakened and the user's freedom of movement is limited. Another effect of failure of ensuring optimization of the superabsorbent polymer (SAP) and pulp is the weakening of the absorbent article capacity. Since the channels in the prior art are weakened on the surface of the absorbent layer, the channel depths must be within certain limits to maintain the integrity of the absorbent layer. Due to the said limits, the channels in the prior art are insufficient in distributing the bodily fluids throughout the surface of the absorbent layer in various absorbent article types and applications.

No technology has been found in the literature for production of absorbent articles, wherein rapid absorption of the bodily fluids is enabled, and which have high absorption and retention capacity and anatomical compatibility, and which does not cause agglomeration / sagging on the user during use. By means of the present invention, a core having a multipartite absorbent layer is produced. Due to its multipartite structure, there is no restriction in the channel structure like there is in the prior art. The invention of the present application has enabled to produce cores wherein channels of desired number, shape and orientation are formed. Therefore, the performance of the core and thus of the absorbent article is enhanced.

The unique absorbent article and absorbent layer developed according to the present invention is a unique application and the first in the world to have high performance superiority in parts where the current channel technology is inadequate and its production technology is completely different from the current channel technology where the fluid passageways are designed.

Summary of the Invention

The objective of the present invention is to provide a partite core production system for an absorbent article wherein the superabsorbent polymer (SAP) and pulp mixture ratios can be adjusted and which comprises multipartite absorbent layers wherein channel shaped gaps are formed between the partite absorbent layers for distribution of the bodily fluids and thus whose performance is enhanced and wherein agglomeration and sagging problems do not occur. Detailed Description of the Invention

An example embodiment of the partite core production system developed to fulfill the objectives of the present invention is shown in the accompanying figures. The details of the invention should be evaluated taking into consideration the entire description, and the description of the accompanying figures is as follows:

Figure 1. is a schematic view of the partite core production system in an example embodiment of the invention.

Figure 2. is a schematic view of the partite core production system comprising three drums in an example embodiment of the invention

Figure 3. is another schematic view of the partite core production system comprising three drums in an example embodiment of the invention Figure 4. is a view of the core comprising cylindrical absorbent layer formed by the partite core production system in an example embodiment of the invention.

Figure 5. is a view of the absorbent article comprising a core formed by the partite core production system comprising two drums in an example embodiment of the invention.

Figure 6. is a view of the core comprising hexagonal absorbent layer formed by the partite core production system comprising two drums in an example embodiment of the invention.

Figure 7. is a view of the absorbent article comprising a core formed by the partite core production system comprising two drums having hexagonal molds in an example embodiment of the invention

Figure 8. is a view of the core comprising rectangular absorbent layer formed by the partite core production system comprising three drums in an example embodiment of the invention. Figure 9. is a view of the absorbent article comprising a core formed by the partite core production system comprising two drums having rectangular molds in an example embodiment of the invention

Figure 10. is a view of the core comprising square absorbent layer formed by the partite core production system comprising two drums in an example embodiment of the invention.

Figure 11. is a view of the core comprising S-shaped absorbent layer formed by the partite core production system comprising three drums in an example embodiment of the invention.

Figure 12. is a view of the absorbent article comprising a core formed by the partite core production system comprising two drums having S-shaped molds in an example embodiment of the invention

Figure 13. is a schematic view of the absorbent layers wrapped such that the fabric ends overlap, in other words, by folding the fabric in the form of a G.

Figure 14. is a schematic view of the absorbent layers which are placed on a fabric surface after leaving the drum molds and which are covered by another fabric, in other words wrapped in the form of a sandwich as fabric - absorbent layer - fabric.

Figure 15. is a schematic view of the absorbent layers wrapped upon folding the ends of the fabric onto the absorbent layers, i.e. folding the fabric in the form of a C, and then placing the core thereon.

The components in the figures are given reference numbers as follows:

1. Partite core production system

2. Drum

3. (SAP) feeding unit

4. Pulp feeding unit

5. Absorbent layer

6. Mold 7. Fabric

8. Production line

9. Channel

10. Core

A. Absorbent article

C. Channel

A partite core production system (1) for absorbent articles (A) of the present application comprises a plurality of cylindrical rotary drums (2), at least one rotating unit for rotating the drums (2) from the center thereof, at least one superabsorbent polymer (SAP) feeding unit (3) and at least one pulp feeding unit (4) provided on the drum (2) for each drum (2), a mold (6) provided on the outer surface of each drum (2) to shape at least one absorbent layer (5), a vacuum unit for creating vacuum in the inner surface of the mold (6) and enabling the absorbent layer (5) to be held in the mold (6), at least one position measuring device for measuring the position of the mold (6), and a control unit which is adapted to create vacuum in the inner surface of the mold (6) by means of the vacuum unit upon receiving the information from the position measuring device that the mold (6) is at the first position where it is aligned with the superab sorbent polymer (SAP) feeding unit (3) and pulp feeding unit (4) and which is adapted to reduce or stop the said vacuum formation upon receiving the information that the mold (6) is at the second position where it is aligned with a fabric (7) located under the drum. The partite core production system (1) comprising three consecutive drums in an example embodiment of the invention is shown in Figure 2.

The partite core production system (1) for absorbent articles (A) of the present application comprises a plurality of rotary drums (2). The rotating unit is adapted to rotate the drum (2) from the center thereof. The rotating unit may be directly connected to the drum (2) or by means of a gear, belt or a similar transmission means. A rotary motor connected to a central shaft of the cylindrical drum (2) may be given as an example to the rotary unit.

The positioning measuring device is for detecting the position of the mold (6) when the drum (2) is rotating. Analog or digital rotary encoders, position sensors and angular position sensors can be given as examples to the position measuring devices in a way not limiting the scope of the invention. While the position measuring device can be adapted to detect the selected positions of the mold (6), it may also adapted to detect the angular position of the mold (6) with respect to the center of the drum (2).

In an example embodiment of the invention, the position measuring device detects that the mold (6) is at a first position where it is aligned with the superabsorbent polymer (SAP) feeding unit (3) and the pulp feeding unit (4) located over the drum (2). When the position measuring device transmits to the control unit the information that the mold (6) has reached the first position, the control unit creates a vacuum on the inner surface of the mold (6) by means of the vacuum unit. The superabsorbent polymer (SAP) and the pulp are filled into the mold (6) by means of the superab sorbent polymer (SAP) feeding unit (3) and the pulp feeding unit (4). The superabsorbent polymer (SAP) and the pulp can be filled/poured into the mold (6) upon being mixed by a mixer preferably in selected proportions. At this stage, an absorbent layer (5) comprising a mixture of superabsorbent polymer (SAP) and pulp is produced in the mold (6). The drum (2) is rotated by the rotating unit thereby changing the position of the mold (6). This process is repeated for each mold (6) provided in each rotating drum (2). During the rotation of the drum (2), the separation/detachment of the absorbent layer (5) from within the mold (6) under the influence of centrifugal force and/or the force of gravity is prevented by the vacuum created on the inner surface of the mold (6). The position measuring device detects when the mold (6) reaches a selected second position where it is aligned with a fabric (7). When the position measuring device transmits to the control unit the information that the mold (6) has reached the second position, the control unit ceases the vacuum on the inner surface of the mold (6). When the vacuum is ceased, the absorbent layer (5) is detached from the mold (6). The selected second position is preferably the position (preferably under the drum (2)) where the mold (6) starts to get aligned with a fabric (7). As a result, the absorbent layer (5) in the mold (6) is positioned on the fabric (7). In the embodiments of the invention, the fabric (7) is preferably a nonwoven fabric (7). The surface of the fabric (7) is preferably coated with an adhesive material for adhesion of the absorbent layer (5). In an example embodiment of the invention, the width of the mold (6) is typically 60-150 mm, more commonly 65-140 mm, and preferably 70-125 mm; and the length thereof is typically 250-600 mm, more commonly 250-550 mm, and preferably 260-500 mm.

In one embodiment of the invention, the controls of the feeding units for the said filling operation are carried out by the control unit. When the position measuring device transmits to the control unit the information that the mold (6) has reached the first position, the control unit starts the operation of filling from the feeding units to the mold (6). A valve, which is preferably provided in the feeding units and can be opened and closed by the control unit, can be used for starting and terminating the filling operation. In an embodiment of the invention which can be adapted to all its embodiments, the superabsorbent polymer (SAP) and pulp received from the feeding units are passed through a mixer where they are mixed then filled into the mold (6).

One embodiment of the invention comprises a production line (8) (e.g. a conveyor belt) which extends under the drum (2) and on which the fabric (7) will be placed. Absorbent layers (5) of selected number and shapes are placed on the fabric (7) provided on the production line (8) by means of the drums (2). As the drum (2) rotates, the production line (8) is advanced thereby enabling arrangement of the absorbent layer (5) parts on the fabric, and thus the production of the core (10) having the desired structure is realized. The same process is applied on another fabric (7) located on the production line (8). Thus, mass production of the core (10) can be carried out. Figures 2 and 3 show the absorbent layers (5) arranged on the fabrics (7) provided on the production line (8) in an example embodiment of the present invention.

In the embodiments of the invention, a plurality of drums (2) located at a selected distance from one another are used. While the drums (2) can be positioned one after the other (e.g. figure 2), they can also be positioned side by side on a single rotating shaft (e.g. figure 3). Both drums (2) are positioned so that their centers are at a selected distance from each other. Thus, between the absorbent layers (5) to be positioned on the fabric (7) side by side by each drum (2), a distance is provided to form a channel (9) / groove / fluid absorption path. On the surface of each drum (2), there is a plurality of molds (6) preferably located at a selected distance from each other. Thus, a natural channel (9) / groove / fluid absorption path of a selected width/length (at least as much as the selected distance) is formed between the absorbent layers (5) (partite absorbent layers (5)) to be positioned by each drum (2) on the fabric (7). The cross sections of the molds (6) can preferably be cylindrical, oval, hexagonal (honeycomb), rectangular, square, circular or S-shaped (see figures 4, 5, 6, 7, 8, 9, 10, 11, 12). Absorbent layers (5) will be adhered to a number of fabrics (7) as much as the number of the drums (2) used. The number of absorbent layers (5) of an absorbent article (A) in the y axis may also vary according to the shape of the drum (2) mold (6) that is used. If a cylindrical, oval and S-shaped mold (6) is used, the absorbent layer (5) adhering to the fabric (7) can be permanently adhered as a single piece and/or, depending on the length of the mold (6) in the y axis, can be added to the fabric (7) as a plurality of absorbent layers (5). Similarly, a plurality of absorbent layers (5) can be positioned on the fabric (7) also with the hexagonal, rectangular and square molds (6) by intermittent application. In this case, depending on the n number of drum (2) molds (6) used in the x axis in the finished absorbent article (A), n-1 number of channels (9) / grooves / fluid absorption paths are formed, and depending on the adhesion of continuous absorbent layers (5) in the y axis of the mold (6), an absorbent layer (5) as a single piece can be obtained from the front to the back along the fabric (7); or depending on the adhesion of m number of hexagonal, square and rectangular absorbent layers (5) from the front to the back on the absorbent article (A) in the y axis of the mold (6), m-1 number of channels (9) / grooves / fluid absorption paths can be obtained. By means of this channel (9) / groove / fluid absorption path formed, the fluid absorption time of the finished absorbent article (A) is significantly reduced compared to the prior art, and the absorption time performance is improved thereby enabling the fluid to be rapidly retained in the absorbent layer and since contact of the skin with the fluid is eliminated in a short period of time, minimizing skin problems such as rashes, redness and allergies. Since the formed structure with channels (9) also facilitates forward and backward distribution of the fluid along the diaper, the capacity of the superab sorbent polymer (SAP) and pulp raw materials at the front and rear regions of the absorbent article, which remain unused in the prior art applications, is enabled to be used efficiently. The problem of superabsorbent polymer (SAP) particles gelling and thus not transmitting the fluid to the other superabsorbent polymer (SAP) particles due to excessive swelling in the case of rapid encounter with the fluid because of the single piece absorbent layer (5) in the current applications is eliminated by means of the originally developed method of producing absorbent articles (A) with channels (9). Since the structure with channels (9) does not wait for the superab sorbent polymer (SAP) particles to receive the fluid and transmit it to the other superabsorbent polymer (SAP) particles due to the rapid fluid absorption, but transmits the fluid to the front and rear regions of the absorbent article (A) particularly in y axis, the probability of gelling of the superabsorbent polymer (SAP) particles is minimized. Thus an absorbent article (A) is produced which has a high capacity and a high sealing performance, and wherein the amount of wetness returned to the skin is minimized.

In one embodiment of the present invention, the absorbent layers (5), which leave the drum (2) molds (6) and are arranged on the fabric (7), can be wrapped such that the ends of the fabric (7) overlap, in other words, by folding the fabric (7) in the form of a G (see figure 13). In another embodiment, the absorbent layers (5) can be wrapped by being covered by another fabric (7), in other words, by being wrapped in the form of a sandwich as fabric (7) - absorbent layer (5) - fabric (5). In another embodiment, the absorbent layers (5) can be wrapped by folding the ends of the fabric (7) on one surface of the absorbent layer (5) onto the absorbent layer (5), in other words, by folding the fabric (7) in the form of a C, and then placing another fabric (7) thereon (see figure 15). With these applications, the absorbent layers (5) and the channels (9) between the absorbent layers (5) are wrapped with the fabric (7). In the wrapping process, an adhesive (e.g. glue) material is used to fix the absorbent layers (5) to the fabric (7), and the positions of the channels (9) are secured. The adhesion process is reinforced by the application of ultrasonic pressure (adhesion of two layers under the influence of the vibration caused by ultrasound waves) and/or mechanical pressure (physical pressure).

By means of the partite core production system (1) for absorbent articles (A) of the present application, cores (10) comprising a plurality of absorbent layers (5) made of superabsorbent polymer (SAP) and pulp mixture can be produced. The absorbent layers (5) are separated by channels (9) and wrapped by fabric (7). Since the process of wrapping with the fabric (7) is supported with the adhesive material, problems such as sagging and agglomeration of the absorbent layer (5) are eliminated.

By means of the channels (9) formed on the core (10), the fluid absorption time of the absorbent article (A) is significantly reduced compared to the prior art and the bodily fluid absorption time performance is improved. Thus, the bodily fluid is enabled to be rapidly retained in the absorbent layer (5), the contact time of the user’s skin with the bodily fluid is reduced, and skin problems such as rashes, redness and allergies are prevented. The channel (9) structure formed by the partite absorbent layers (5) of the core (10) also facilitates the distribution of the bodily fluids forward and backward along the core (10). Thus, the capacity of the superabsorbent polymer and pulp raw materials at the front and rear regions of the absorbent article (A), which remain unused in the prior art applications, is enabled to be used efficiently. By producing a partite absorbent layer (5), the surface area of the absorbent layer (5) is increased, and channels (9) effective in fluid distribution are formed. As a result of the increase in the surface area and effective fluid distribution of the said channels (9), fluid distribution is realized to the front and rear regions of the absorbent article (A) without depending on the fluid distribution between the superabsorbent polymer particles, and the probability of gelling of the superabsorbent polymer particles is minimized. Thus an absorbent article (A) is obtained, which has a high capacity in retaining bodily fluids and a high sealing performance, and wherein the amount of wetness returned to the skin is minimized.

Claims

1. A partite core production system (1) for absorbent articles (A) comprising a plurality of cylindrical rotary drums (2) and at least one rotating unit for rotating the drums (2) from the center thereof; and characterized by at least one superabsorbent polymer (SAP) feeding unit (3) and at least one pulp feeding unit (4) provided on the drum (2) for each drum (2), a mold (6) provided on the outer surface of each drum (2) to shape at least one absorbent layer (5), a vacuum unit for creating vacuum in the inner surface of the mold (6) and enabling the absorbent layer (5) to be held in the mold (6), at least one position measuring device for measuring the position of the mold (6), and a control unit which is adapted to create vacuum in the inner surface of the mold (6) by means of the vacuum unit upon receiving the information from the position measuring device that the mold (6) is at the first position where it is aligned with the superabsorbent polymer (SAP) feeding unit (3) and pulp feeding unit (4) and which is adapted to reduce or stop the said vacuum formation upon receiving the information that the mold (6) is at the second position where it is aligned with a fabric (7) located under the drum.

2. Partite core production system (1) according to Claim 1, comprising a rotating unit which is a rotary motor connected to a central shaft at the center of the drum (2).

3. Partite core production system (1) according to any one of the preceding claims comprising a position measuring device which is an encoder and/or position sensor and/or angular position sensor.

4. Partite core production system (1) according to any one of the preceding claims, comprising nonwoven fabric.

5. Partite core production system (1) according to any one of the preceding claims, comprising a fabric coated with an adhesive material.

6. Partite core production system (1) according to any one of the preceding claims, comprising a valve, which is located at the superabsorbent polymer (SAP) feeding unit (3) and the pulp feeding unit (4), and which can be opened and closed by the control unit.

7. Partite core production system (1) according to any one of the preceding claims, comprising a mixer, which mixes superabsorbent polymer (SAP) it receives from the superabsorbent polymer (SAP) feeding unit (3) with the pulp from the pulp feeding unit (4).

8. Partite core production system (1) according to any one of the preceding claims, comprising a production line which extends under drum (2) and is used for placing the fabric thereon.

9. Partite core production system (1) according to any one of the preceding claims, comprising the mold (6) having cylindrical, oval, hexagonal, rectangular, square, circular or S-shaped cross-section.

10. Partite core production system (1) according to any one of the preceding claims, comprising drums (2) which are positioned at a selected distance from one another.

11. Partite core production system (1) according to any one of the preceding claims, comprising molds (6) which are positioned at a selected distance from one another.