WO2003034963A2

WO2003034963A2 - Absorbent product with binder

Info

Publication number: WO2003034963A2
Application number: PCT/EP2002/011535
Authority: WO
Inventors: Herbert F. Gerlach; Valentino Zappa
Original assignee: Korma S.P.A.
Priority date: 2001-10-25
Filing date: 2002-10-16
Publication date: 2003-05-01
Also published as: AU2002350548A1; EP1437995A2; DE10152155A1; DE10152155B4; WO2003034963A3

Abstract

This invention concerns an absorbent (1) consisting of a first surface (3) and a second surface (4), between which at least one absorbing material (10) is arranged. A contrasting agent (7) is arranged in the area of the absorbing material (10).

Description

Absorbent with binder

This invention concerns an absorbent consisting of a first surface and a second surface, between which at least one absorbing material is arranged. The first and second surfaces are linked to one another in such a way as to fully close up the absorbing material, where the latter is capable of absorbing at least liquids or gases, and at least one of the surfaces is permeable to liquids.

From EP 0 875 224 A1 there results an absorbent with bag-like structure. A superabsorbent is arranged in the bag. The quantity as well as the position of the superabsorbent is given by the bag shape. From WO 92/19198 results that particles, and especially superabsorbents, are applied to a smooth surface through a perforated pattern and are eventually processed into an absorbent. The pertaining equipment for the particles application is known from WO 92/19388. From WO 94/01069 results that a superabsorbent is arranged between the first and second layer and the superabsorbent is bound to the layers by means of a binding agent. Both layers show a flat condition when applied onto one another.

Proceeding from said state of the art, the present aim is to devise an absorbent whose structure enables to check the surface distribution of the material used.

This task is accomplished by an absorbent having the characteristics of requisition 1 , by means of an equipment having the characteristics of requisitions 12 and 15, and by means of a process having the characteristics of requisition 18. Further suggested details are explained in the following requisitions.

This invention concerns an absorbent consisting of a first and second surface, between which at least one absorbing material is arranged. The first and second surfaces are linked to one another in such a way as to fully close up the absorbing material. The absorbing material is capable of absorbing at least liquids and gases, and at least one of the surfaces is permeable to liquids. According to the invention, in the area with the absorbing material the absorbent contains a contrasting agent. The contrasting agent is perceptible by means of automatic detection, so that various processing steps can be undertaken by interpreting the automatic detection itself. For instance, from the position, the distribution and heaping of the contrasting agent it is possible to act back on the processing steps. If for example the contrasting agent is detected in an area where it should not be present, it is possible to operate an automatic adjustment of the regulating members, and if certain limit values are exceeded, the machine output can be automatically interrupted. This avoids producing waste goods, which would otherwise be located only at the final control.

The contrasting agent should preferably be solid, and precisely in granules. For example the contrasting agent can be in the form of granulate or powder. The contrasting agent can be applied by means of a sprinkling device or of a proportioning device. However, the contrasting agent may also be liquid, for example as gel. It can be applied by sprinkling or impregnation. In particular, the contrasting agent is capable of softening under heat effect as well as of changing its aggregate condition. After ensuing cooling, the contrasting agent can solidify again.

The absorbent shows a first surface which is permeable enough to allow detecting the contrasting agent through it. For example, said surface may be translucent, opaque. The suitable layers, whose components and structure result from EP 0 634 920 B1 , EP 0 347 745 A and from the documents mentioned therein, are all included within the framework of this publication. The surface of the first layer is possibly structured in such a way as not to produce any dispersion effects, which may falsify the detection results. The surface can therefore show for instance a micro-geometry providing for surface dulling. Examples of suitable surface geometries result from US 4,463,045 included within the framework of this publication.

The contrasting agent has a colour or rather emits rays, perceivable through the above mentioned first surface also to the naked eye. Suitable shades are high colours such as blue, black, red or brown, as well as all possible colour combinations. The choice of the contrasting agent to be used depends on the kind and structure of the adjoining materials. According to one development, the contrasting agent must be able to stand out against the material or materials. The choice can also be influenced by the detection kind, which can be based on optical process, on electromagnetic process, or on a mixture of different detection processes.

The choice of the contrasting agent will fall on a colour capable of covering the tinge of another material contained in the absorbent. For instance, from EP 0 643 955 B1 , which within the framework of the publication includes full description of the absorbent used therein, there result a sphagnum-moos compound and process to produce layered absorbents. The natural absorbing material on vegetable basis has a dark shade of colour. So the suitable contrasting agent for detection should have a light hue standing out against the dark background.

According to one development, the binder containing the contrasting agent is added to the absorbing material. For instance, from the above mentioned WO94/01069 there results the use as binders of suitable polymeric materials, where the used polymers, kind of feed and application as well as absorbent production are included within the frame of this publication according to said document. The contrasting agent may be added to the polymeric material. The contrasting agent may even be part of the binder itself, for instance by using one or more suitable contrasting pigments.

According to one development, the binder is evenly arranged on the whole surface of the absorbing material. The contrasting agent, which for instance may be applied along with the binder, is also arranged on the whole surface of the absorbing material. This then allows to check the exact form, structure and/or position of the absorbing material on a surface.

According to another development, the binder is blended with the absorbing material. This offers the advantage of allowing to detect the position of the absorbing material especially with a uniform distribution of the contrasting agent in the binder and ensuing uniform distribution of absorbing material and binder also in the absorbing material. At the same time, it is also possible to check the distribution of the binder in the absorbing material. Through the more or less fixed quantity proportions, the possibility is also given to check and ascertain weight and quantity of the materials inside an absorbent after applying the materials themselves. This is possible on a production line as well as within the framework of the final control of the individual resulting products.

A polymer mixed with a contrasting agent should preferably be used as binder. Polyolefins, compounds thereof and especially polyethlene have turned out to be suitable polymers. It is also possible to use polyester. Under temperature influence, the latter, just like other suitable materials, shows adhesive characteristics. This leads to binding the absorbing materials used, but also the contrasting agent. After cooling, the materials stay in place even if their position changes, so that the detection results are reliable also in the following processing steps.

The detection process can be carried out from above, from underneath, from the side or even from the corner. It is also possible to carry out repeated successive or contemporary detections. For instance, the detectors applied to a production line can be differently set in their positions. Systems which can be applied partly with changes, result for example from DE 195 00 822 C1 using ultrasound, or from DE 35 114 74 A1 using optoelectronic means.

The absorbent should preferably contain a contrasting agent radiating a wave-length between 1 nm and 1*10^"2, or rather which is detectable at such range. According to another development, the contrasting agent may be externally activated, so that it can radiate independently, for example by means of phosphorizing or glowing effects. Further, it is possible to employ and distinguish different contrasting agents, for example in order to check the structure of different layers as well as their position in the absorbent. It has proved quite convenient when the contrasting agent has always approximately the same proportion to the quantity of absorbing material.

According to another development, the contrasting agent is added for example in the form of strips, where the first strip goes the whole length of the absorbing layer, from beginning to end, and the second strip is applied transversally across the width of the absorbing layer. According to another development, only the outline of the absorbing layer is detectable by means of the contrasting agent, since the remaining surface has either no or very little concentrations of contrasting agent. The concentration of contrasting agent in the absorbent depends for example on the detection method, on the contrasting agent used, on the other materials used, on the separation fineness necessary for detection, as well as on other parameters. For example, it is also possible to dye a material with contrasting agent. With respect to a material absorbing the contrasting agent, the concentration of the latter can range from 0,05% to over 15%. Further, the necessary concentration may be affected by the fact that the surface covering the contrasting agent has itself been dyed for example by means of titanium dioxide. The respective dye and dyeing grade have already been hinted at in connection with the proper surfaces resulting from the mentioned documents. It is also possible to use a gas-absorbing material in the absorbent, for example in view of smell inhibition or smell processing. This can also contain the contrasting material, for example in the form of dyeing. Possible materials to be used are for example calcium carbonate, silicate, kaolin, plaster and pertaining compounds.

In order to be able to detect the layout of the absorbing material, the absorbent preferably presents a zeolite of the absorbing material with contrasting agent. The zeolite material can for example be dyed. According to another development, an absorbing powder contains the contrasting agent, or rather the powder is added only in the area of the absorbing material, which besides the function as contrasting agent also presents another function. The contrasting agent is preferably applied on the whole surface of the absorbing material and/or perfectly mixed with the absorbing material.

According to another concept of the invention, the contrasting agent is fed by means of an absorbent production device, which allows the contrasting agent to get into contact with the absorbing material. This can be attained through a proper mechanic feeding before or even during the material application on a surface. The contrasting agent feed is structured in such a way as to allow a perfect blending of the contrasting agent with the absorbing material. Another development provides for the contemporary feeding of a binder on the contrasting agent. The contrasting agent feed can be structured in such a way as to allow applying all the materials to be dispensed on a surface. Another concept of the invention envisages a detection unit on the absorber production device, capable of detecting the contrasting agent. One or more detection units can be used, also with different application aims. For example, a detection unit can be used to check whether the material is correctly distributed or positioned on the surface. Detecting can take place from the side and/or from above. Another detection unit can be used for example to check the material on the surface used, thanks to the contrasting function of the agent. For example it is possible to check the type of foil, nonwoven or woven material.

Another possibility is to locate displaced material quantities with the aid of the contrasting agent. A high production speed may result in turbulences or other effects causing the material to be spilled. Said material may end up in an area which in the next processing should have no or at the most very little material on it. A typical example for this are the sealing areas where both layers have to come into contact and be, for example, glued together. The material spilled in said spots can lead to a faulty final product. By means of proper evaluation of the warnings received, it can be possible to locate such defective spots, mark them and eventually sort them out, or subject them to further tests.

When a processing width is available which allows the juxtaposition of several absorbing mats to be eventually separated from one another, another detection possibility is to check the positioning of the mats. In case the given threshold values are exceeded, it is possible for example to ^"arrange automatic adjusting. Another development provides for supervision of a separation line free of material, in view of the ensuing separation of the individual absorbing mats.

It is further possible to check and possibly adjust the size of the absorbing mat by means of a detection unit with the aid of the contrasting agent. Besides absorbing mats in a square shape, it is also possible to arrange the absorbing material in curved and even round shapes. The shape of the absorbing mat may also for example have the form of the typical hygiene articles. The detection unit should possibly check and if necessary adjust at least the width of an absorbing mat. The absorber production device should possibly have a controlling unit capable of processing the detection warning produced with the aid of the contrasting agent. A further development provides for a control unit capable of producing a warning signal in case of value deviation in connection with the contrasting agent. Said warning will then produce a change to the present production step of the absorbent.

In particular, the contrasting agent is used to locate an absorbing area with expected absorption of liquid and/or gas, and ensuing smell production. For example, the first layer, can be coated, so that the contrasting agent then helps locate those areas which have to be kept free from coating in order to grant the future absorbing capacity.

Checking of the absorbing material is possibly achieved by adding a contrasting agent to a binder so as to grant controllability of the binder application. A binder with polymer should preferably be used, where the latter melts just like the contrasting agent. Further suitable binders as well as their application result for example from EP 0 720 488 B1 , EP 0 592 001 A1 e EP 0 666 350 B1 , whose contents on this regard are included in the publication in hand.

Regarding the absorbent production process, the materials used and the application fields, as well as the suitable detection means, reference is made to the declarant's still unpublished DE 101 23 099.0, which is made reference to on this regard within the framework of the publication at hand.

Other favourable structures and properties are shown in the following drawing, which along with the described properties allows to obtain further functional combinations not explained in detail here. They are:

Figure 1 view of a surface carrying several absorbent mats and Figure 2 schematic view of an absorbent production device

Fig. 1 shows a schematic view of joint absorbents 1. Absorbents 1 have several absorbing mats 2, where the structure of absorbents 1 preferably consists of the first surface 3, at least one inserted material layer 4 and a final second surface 5. Absorbents 1 may however also consist of several structures of this kind laid on one another, or rather of several material layers 4, especially absorbent layers. This is possible for example by folding absorbent 1 , or by repeated coating. Further, according to the described production method, absorbents 1 have been applied a sealing in cross-direction 5 as well as in machine direction 6. Both sealings 5 and 6 should preferably be continuous, that is unbroken. In another development, one or both sealings 5 and 6 are interrupted at certain spots. Material layer 4 presents a contrasting agent 7, which according to the present version is uniformly distributed in material layer 4. This enables for example to check the shape of the material layer by automatically controlling the detected contrasting agent.

Figure 1 also shows a diagram of detection unit 8. Sensor 9 is capable of detecting an active or passive warning from contrasting agent 7, which is then interpreted by detection unit 8. The detected signal can for example inform a cutting system, for a cut through the material layers 4 in cross direction, but also in machine direction by detecting contrasting agent 7 in view of separating absorbents 1. Further, absorbent 1 may have additional markings such as for example grooves, coloured markings or such. Contrasting agent 7 also allows to detect a projection of absorbent 1 , so that it may inform about the areas where a material layer 4 is present. It is also possible - by lighting absorbent 1 and eventually undertaking a light and shade comparison for example by assessing CCD-camera photographs with the aid of contrasting agent 7 - to draw inferences about the distribution of absorbing material 10 and to obtain pertaining resulting information. According to one development, the detection unit allows to check the applied binder containing contrasting agent 7. Moreover, the above mentioned detection unit 8, along with the various detecting possibilities, can be used not only to carry out cuts on absorbent 1. For example there is also the possibility of checking material layer 4 during or before further processing, for example in case of storing in the desired transport form by means of a packaging unit or a processing unit for the production of the final product. As expounded, it is possible to position the absorbent layers to be sealed in cross direction both in a parallel and in an alternate arrangement.

Figure 2 shows a schematic view of a possible device 11 for absorbent production. The first cylinder 12 continuously conveys the first surface 2 to a feeding unit 13 equipped with an integrated contrasting agent feed 14. Through feeding unit 13, the contrasting agent 7 with absorbing material 10 and binder 15 are applied to the first surface 2, according to the described device 11. It is then possible to detect the contrasting agent by means of sensor 9. Finally, the second cylinder 16 applies a second surface 4 onto the first surface 2, and then - for instance after heat treatment - there takes place the separation into individual absorbents, which are not described in detail here.

The invention also allows to check the separate packaging of the individual absorbents into the transportation form. The single absorbing layers can then be combined in a purpose-built processing station or in correspondence with the final product. For example, in the hygiene as well as incontinence fields it is possible to diversify the positioning of the absorbing material in the diaper for the two sexes according to the genitalia position.

The suggested method as well as the absorbents are suitable for processing of the most diverse materials. As first as well as second layers it is possible to use fabrics, paper, nonwovens, especially airlaid materials, films or other thin-surface materials as well as multi-layer material blends. As material, and in particular absorbing material, it is possible to use SAP, black carbon, zeolite, alone, blended, compound with polymer or other materials. In particular, the absorbents attainable according to the invention can be used in the following applications: hygiene products, such as sanitary towels, diapers or absorbing pads for breastfeeding mothers, incontinence products such as absorbing shields, food technology such as meat underlying protection and food packaging, smell control, absorbing pads, especially for industrial purposes such as oil absorption, absorption of liquids, especially leakage liquids, for washing pads, to be used in washing machines equipped with olfactory substances or detergents, for medical needs such as blood absorbing materials for operation theatres, for coverings, cleaning materials for operation theatres and surgery clothing, for clothes, clothes detergents in general, also in washing cloths, dusters, tissues, in the household, for food transportation, for frozen goods, for goods which may leak liquids, as barrier against hole obstruction achieved by swelling out, in building constructions, as sealant against dampness penetration, in particular for the absorption of air humidity, for example for dry storing of electronic components or optical devices, as underlying protection as well as covering.

Claims

1. Absorbent (1) with first surface (3) and second surface (4), between which at least one absorbing material (10) is positioned and where the first (3) and second (4) surfaces are bound together in such a way as to close up the absorbing material (10) within the surfaces, and the absorbing material is capable of absorbing at least liquids and gases, and where at least one of the surfaces (3, 4) is permeable to liquids, characterised by presenting a contrasting agent (7) in the absorbing material (10) area.

2. Absorbent (1 ) according to requisition 1 , characterised by containing a contrasting agent (7) in solid form, especially granulate.

3. Absorbent (1 ) according to requisition 1 , characterised by containing a contrasting agent (7) in liquid form.

4. Absorbent (1) according to requisitions 1 , 2 or 3, characterised by having a permeable first surface (3) where the contrasting agent (7) is detectable through the first surface (3) itself.

5. Absorber (1 ) according to one of the previous requisitions, characterised by having a binder added to the absorbing material (10), where the binder contains the contrasting agent (7).

6. Absorbent (1 ) according to one of the previous requisitions, characterised by a zeolite of the absorbent material (10) containing the contrasting agent (7).

7. Absorbent (1 ) according to one of the previous requisitions, characterised by a powder containing the contrasting agent (7).

8. Absorber (1 ) according to requisitions 5, 6 or 7, characterised by having the contrasting agent (7) applied on the whole surface of the absorbing material (10) and/or perfectly mixed with the absorbing material (10).

9. Absorbent (1 ) according to one of the previous requisitions, characterised by the contrasting agent (7) emitting a wave length between 1 nm and 1 *10^"2.

10. Absorber (1 ) according to one of the previous requisitions, characterised by a contrasting agent (7) that can be activated.

11. Absorber (1 ) according to one of the previous requisitions, characterised by having quite a fixed proportion between a quantity of the contrasting agent (7) and a quantity of absorbing material (10).

12. Device (11 ) for the production of absorbent (1) according to requisition 1 , characterised by the device (11 ) having a contrasting agent feed (14) through which the contrasting agent (7) gets into contact with the absorbing material (10).

13. Device (11) according to requisition 12, characterised by the contrasting agent feed (14) allowing to mix the contrasting agent (7) with the absorbing material (10).

14. Device (11 ) according to requisition 12 or 13, characterised by the possibility of simultaneously feeding a binder (15) through the contrasting agent feed (14).

15. Device (11 ) for the production of absorbent (1) according to requisition 1 , characterised by the device (11) having a detection unit (8) allowing to detect the contrasting agent (7).

16. Device (11 ) according to requisition 15, characterised by the device (11 ) equipped with a control capable of processing the detected signal in connection with the contrasting agent (7).

17. Device (11 ) according to requisition 16, characterised by the control being structured in such a way as to produce a signal in case of deviating values detected in connection with the contrasting agent (7), where said signal activates a change to the processing step under way for the production of the absorbent (1).

18. Production process for absorbent (1 ) according to requisition 1, characterised by having a contrasting agent (7) added to the binder (15) so as to grant the controllability of the binder application.

19. Binder (15) for absorbent (1) according to requisition (1), characterised by having a contrasting agent (7) mixed with the binder (15).

20. Absorbing material (10) for absorbent (1 ) according to requisition 1 , characterised by the absorbing material (10) having a contrasting agent (7).

21. Use of contrasting agent (7) for absorbent (1 ) according to requisition (1 ).