NL8902635A - Incontinence pad mfg. appts. - uses heat source and roller pressure to produce layers of varying thickness and absorbency - Google Patents

Abstract

Material (5) of constant thickness is absorbent. The bottom layer (6) is of impermeable material while the top player (16) is liquid-impermeable. The absorbent layer is subject to a heat source (7) and to pressure (8) to achieve the required adhesion. Pressure is applied by roller (9) rotating on a shaft (10) which is movable up and down w.r.t. the centre line (11). Opposite this roller is a second roller (12). In the nip between the rollers runs a support layer (13), on top of this a rear layer, then a layer of absorbent material, then the top layer. When the nip is at max. the absorbing layer is at min. (14). When the rollers rotate half a turn the nip is max., thus producing a thicker section (15). A cutter roller (17) has a knife (18), and its circumference is equal to the distance between the thin area (14), thus material is at thinnest section of material length.

Description

Absorbent body, as well as method and device for the manufacture thereof.

The invention relates to an absorbent body for use in, for example, diapers, incontinence, wound or sanitary napkin, comprising material with a capillary structure, wherein in an area near the point of micturition the cross-sectional size of the capillaries is relatively large and in at least one other area is relatively small such that liquids contained in the former region attempt to flow to the latter region.

Such an absorbent body is known from EP-B-169.] 84. This known absorbent body has a capillary structure in which the cross-sectional dimensions of the capillaries are greatest on the side facing the user and smaller on the side facing away from it. This ensures that the body fluids do not remain on the side facing the user, but are more or less drawn into the interior of the absorbent body.

The known absorbent body is covered on the user-facing side with a liquid-permeable nonwoven layer, and on the opposite side with a protective liquid-impermeable layer.

The absorbent body is required to absorb, distribute and retain the fluid offered as quickly as possible, even under pressure. Heretofore, predominantly use has been made of loose fibers of wood pulp (fluff) in the capillary structure of which the liquid can move and be retained. In addition, super absorbers are often added. These products form a gel with liquids and are therefore able to retain liquid under pressure. However, this also means that they can block the fluid transport when they fill the capillaries.

It is known that absorption material with a low density (or large porosity) can retain a lot of liquid and has a low radiation resistance. However, this structure is less able to transport liquid to more distant parts of the system if it is to be done vertically (against gravity). High density material (low porosity), on the other hand, does have the required greater suction power, but again has the disadvantage of a higher flow resistance and a lower absorption capacity.

It is known that the known absorbent bodies can still leak at large micturitions. This is because a lot of liquid is not absorbed directly and instead flows over the surface of the dressing to the sides. If the edges of the incontinence bandage do not fit very well to the skin, the fluid between the bandage and the skin will flow out. There is a clear need for users with high micturition needs for a product that can absorb the liquid faster and distribute it over a larger area across the system.

Absorbent bodies generally consist of one absorbent core over the entire surface, the construction and composition of which need not be the same in all places. This includes locally added superabsorbents and locally applied compactions of the structure, the latter often in the form of diamond patterns. The compactions serve, among other things, to improve moisture transport, the superabsorbers have a function in retaining the liquid under pressure. The part of the bandage may also be thickened and / or pressed more heavily at the discharge point.

However, all these measures have not yet led to a sufficient improvement of the absorbent properties.

The object of the invention is now to provide an absorbent body of the type mentioned in the preamble which exhibits better behavior with larger micturitions. This is accomplished in that those areas are juxtaposed in a direction perpendicular to the thickness direction of the body, such that the fluids to be absorbed attempt to travel from the micturition point to an edge of the body adjacent to an area of relatively small cross-sectional capillaries. to flow.

Thanks to this course of the capillaries, a larger part of the absorbent body can now be usefully used for absorbing liquids. At the point of micturition, the liquid can be quickly discharged, thanks to the relatively wide capillaries, to the more distant areas where the liquid is retained in the narrower capillaries. This is particularly important with a U-shaped absorbent body applied to the user. According to the invention, the liquids can now be sucked up from the low-lying micturition point to the higher parts, whereby the body is used optimally and can absorb as much liquid as possible without the risk of leakage.

This is evident from an experiment, for example. Two 24 cm strips cut from the length of a fluff built-up diaper were both dipped in test liquid with one end. The first diaper had a constant density over the entire length and a value of about 100 kg / m 2, which is common for this product.

This is achieved by clamping the diaper between two parallel plates over the entire length. These plates are made of a translucent plastic to follow the course of the liquid rise. In the second diaper, the density varied over the height; at the bottom the value was 75 kg / m ^, at the top it was 350 kg / m ^. This was accomplished by clamping the diaper between two plates that were clamped closer together. In the first diaper, after 7 seconds, 1 min and 4 min, approx. Heights of 2, 4 and 8 cm respectively. reached. After 16 minutes, the ascent stopped at a height of 10 cm. In the second diaper, the heights reached after 7 seconds, 1 min and 4 min were 3, 7 and 14 cm, respectively. After 20 minutes, the diaper was moistened to the maximum height, 24 cm.

In general, the absorbent body is designed as a pad with a thickness considerably smaller than its length and width. Once applied to the user, as mentioned, it has a U-shape, the longitudinal direction of which is curved. This is the case, for example, with diapers. In such applications, in order to be able to make the desired optimum use for the absorbent body, it is provided, according to a preferred embodiment, that the cross-sectional dimensions of the capillaries decrease from the center of the cushion to the transverse edges.

In this embodiment, the collected liquid can be discharged to and retained in the higher parts of the absorbent body. Even if the user is lying or sitting, while exerting a certain pressure on these higher parts, the liquid can still be retained properly thanks to the narrow capillaries in those parts.

Of course, it may also be envisaged that the cross-sectional dimensions of the capillaries decrease from the center of the pad to the longitudinal sides.

Practical tests have shown that the best results are obtained if the cross-sectional dimensions of the capillaries decrease approximately inversely proportional to the distance to the micturition point, where their largest cross-sectional dimensions are.

Thus, the present invention is based on the fact that a gradual reduction of the capillary cross-sectional dimensions is made in the direction of material further away from the micturition point. As a result, the flow resistance is kept small in the vicinity of the micturition point and the suction force is maintained at a greater distance from the micturition point. In order not to increase the flow resistance of areas further away from the micturition point due to the higher density or swelling of the superabsorbers present, provision may be made for the capillary structure to be at least near the areas where the diameter of the capillaries is smallest when wetted. can swell, such that these capillaries become larger. The latter is possible, for example, in that the ability to swell is provided by the wetting-out of dried stresses, which are obtained, for example, by means of separately introduced rigid fibers, powder, microspheres or sponge-like structures and which relax or change shape after wetting. These fibers can also have a function in retaining the fluid under pressure, which is important in the areas where this suction is needed, namely outside the crotch, where the dressing can be pressurized (in sitting or lying positions) of the user).

The invention further relates to a method of manufacturing an absorbent body. In a possible method, as is known, a strip of starting material with a thermal binder or shrinking fibers is formed into a capillary structure under the influence of heat and / or pressure. For the manufacture of the absorbent bodies according to the invention, it is now provided, according to a first variant, that the material with capillary structure is compressed in varying degrees in the longitudinal direction, such that regularly spaced relatively strongly compressed areas with relatively less strength in between. compressed areas are formed, and then the strip is cut transversely at the location of the relatively highly compressed areas.

According to a second variant, however, it can also be provided that the material with the capillary structure is compressed to a varying degree in the transverse direction, such that a relatively less strongly compressed area is formed in that direction in the center, and that the strip is then transversely moved in a regular manner. distances.

Finally, the invention also relates to a device for carrying out the first variant of the method according to the invention, which device is provided in known manner with supply means for a strip of absorbent material, heating and pressure means for forming a capillary structure in said absorbent material, as well as cutting means for cutting it.

For carrying out the first variant of the method, the device is designed in such a way that as pressure medium a pair of rollers is used, one or both of which is suspended movably towards or away from the other, such that during rotation of the rollers a largest and smallest pinch the size of which corresponds to the thickness of the relatively weak and highly compressed areas, respectively.

The invention will now be elucidated on the basis of some exemplary embodiments shown in the figures.

Fig. 1 shows a first embodiment of the absorbent body according to the invention in perspective.

Fig. 2 shows a second embodiment of the absorbent body.

Fig. 3 schematically shows a perspective device for manufacturing the absorbent body.

The absorbent body 1 shown in Fig. 1 consists of material with a capillary structure, such as, for example, loose fibers of wood pulp (fluff), which are optionally held together by any suitable binding agent.

In Fig. 1, the absorbent body is shown in a curved position, which corresponds to the position that the body assumes when applied to the user. In that state, the supply of bodily fluids mostly takes place at the micturition point 2 indicated by the arrow. At that micturition point 2, a certain amount of liquid must therefore be absorbed in a relatively short time, in order to prevent the liquid from escaping near the side edges 3 of the body 1.

For this purpose the body 1 has a fiber structure with relatively wide capillaries near the point of micturition 2. A fairly large amount of liquid can be quickly absorbed in such a structure. However, as soon as all capillaries are filled with liquid, no further liquid can be absorbed near the micturition point 2 of the body 1, so that there is still the risk that escape takes place near the side edges 3. In addition, the micturition point 2 generally located at the lowest point of the body 1, so that gravity generally has an adverse effect on the passage of the liquid to the generally higher parts 4 of the body 1.

According to the invention, these generally higher parts 4 are now more compressed than the part near the micturition point 2, so that these parts 4 have a structure with finer capillaries than the part 2 of the absorbent body 1. These capillaries with smaller cross-sectional dimensions therefore have a greater suction power than the capillaries with larger cross-sectional dimensions, which means that they are able to suck up the liquid from the part 2 to those parts 4. On the other hand, the capillaries with smaller cross-sectional dimensions show better behavior with regard to retaining the liquid, also when pressure is exerted on the body 1, as is the case, for example, when the user is sitting or lying down.

In order to still increase the absorption capacity of the parts 4 located higher up, fibers can for instance be provided there which swell as soon as they become moist.

However, it is also possible to obtain the variation in the size of the capillaries by locally applying fibers of varying cross-sectional dimensions, whereby coarser fibers must then be introduced, for example, near the point of micturition. Furthermore, this course could be obtained by, for example, placing powder or microspheres between the fibers.

Fig. 2 shows a second embodiment of the body having a constant thickness. However, the higher parts 20 are also more compressed here than the area near the micturition point 21. This can be achieved by giving the areas corresponding to the parts 20 in the initial state, before the body has been pressed. During pressing, those areas are then compressed more strongly, so that the desired course in the cross-sectional dimensions of the capillaries is obtained.

Fig. 3 schematically shows a device for manufacturing an absorbent body according to the invention with varying capillary cross-section dimensions.

This is based on a layer of material 5 of constant thickness consisting of an absorbent material, a back layer 6 of liquid-impermeable material and a top layer 16 of liquid-permeable material. The layer of absorbent material is subjected to heat at 7 and pressure at 8 to provide the desired consistency. The pressure is applied at 8 by means of a roller 9, which is rotatable about an axis 10 which is arranged reciprocally, transversely to center line 11. Opposite this roller 9, there is a roller 12. In the nip between both rollers 9, 12 first run a supporting layer 13, on which the back layer 6, the layer of absorbent material 5 and then the top layer 16. In the illustrated position, the nip between rollers 9 and 12 is just as small as possible, wherein in the layer of absorbent material strongly compressed portion 14 is formed. When the roller rotates by half a revolution, the nip is made as large as possible, whereby a less strongly compressed portion 15 is then formed.

A cutting roller 17 is also provided which carries a cutting blade 18. The circumference of the cutting roller 17 corresponds to the distance between two strongly compressed parts 14 of the absorbent material 5. As shown in the figure, the layer of absorbent material 5 is just cut in one of the most compressed areas 14. In this case, separate absorbent bodies 1, as shown in Fig. 1, each having a relatively thick portion 3 and two relatively thin portions 4.

Subsequently, the bodies 1 are further transported on the support layer 13, in order to be processed into finished diapers in a known manner.

Claims (9)

An absorbent body for use in, for example, diapers, incontinence wound or sanitary napkin, comprising material having a capillary structure, in which the cross-sectional dimensions of the capillaries are relatively large in one area near the point of micturition and proportionally in at least one other area. are small such that liquids that can be contained in the former region attempt to flow to the latter region, characterized in that those regions lie in a direction perpendicular to the thickness direction of the body, such that the liquids to be absorbed from attempt to flow the point of micturition towards an edge of the body located near an area of capillaries of relatively small cross-sectional dimensions. Absorbent body according to claim 1, designed as a pad with a thickness considerably smaller than its length and width, characterized in that the cross-sectional dimensions of the capillaries decrease from the center of the pad to the transverse edges. Absorbent body according to claim 1 or 2, designed as a cushion with a thickness considerably smaller than its length and width, characterized in that the cross-sectional dimensions of the capillaries decrease from the center of the cushion to the longitudinal edges. Absorbent body according to any one of the preceding claims, characterized in that the average cross-sectional dimensions of the capillaries are approximately inversely proportional to the distance from the point of micturition. Absorbent body according to any one of the preceding claims, wherein the capillary structure can swell at least near the areas where the cross-sectional dimensions of the capillaries are smallest on wetting, such that these capillaries become larger, characterized in that the ability to swell is provided by the release of dried stresses during wetting, which are obtained, for example, by means of separately introduced rigid fibers, powder, microspheres or sponge-like structures. A method of manufacturing an absorbent body according to claim 2 or according to any one of claims 3, 4 or 5 in combination with claim 2, wherein a strip of starting material with a thermal binder or shrinking fibers is formed under the influence of heat and pressure. capillary structure, characterized in that the material having the capillary structure is compressed in the longitudinal direction to varying degrees, such that regularly spaced relatively strongly compressed areas with relatively less compressed areas are formed therebetween, and subsequently the strip is transversely is cut at the location of the relatively strongly compressed areas. A method for manufacturing an absorbent body according to claim 2, according to any one of claims 3, 4 or 5 in combination with claim 2, or according to claim 6, wherein a strip of starting material with a thermal binder or shrinking fibers under the influence of heat and pressure is formed into a capillary structure, characterized in that the material with the capillary structure is compressed to different degrees in the transverse direction, such that a relatively less strongly compressed area is formed in the center in that direction, and then the strip in the transverse direction cut at regular intervals. The method of manufacturing an absorbent body according to claim 6, characterized in that uneven amounts of starting material are longitudinally applied in the strip such that longitudinally spaced raised areas are formed, and the strip is then compressed becomes essentially constant in longitudinal direction. 9. Device for manufacturing an absorbent body according to the method of claim 6, or 6 and 7, comprising supply means for a strip of absorbent material, heating and pressure means for forming a capillary structure in said absorbent material, and cutting means for cutting through, characterized in that as pressure medium a pair of rollers is used, one or both of which is suspended and movable towards the other, respectively, which form a largest and smallest pinch, the size of which corresponds to the thickness of the relative weak and strongly compressed areas.