DE2348430A1 - MULTILAYER DIAPER - Google Patents

Description

PA TENTANIA / JC L ΓΕ

. S2ic6ard '^ Jfüffer-JSörmr 2 3 A 8 4 3

PATENT Attorney DlPL-ING. R. MDLLER-BDRNER PATENTANWALT DIPL.-ING. HANS-H. WEY

! BERLIN-DAHLEM 33 -PODBIE LS KIA LLE E 68 8 MÖNCHEN 22. WIDENM AY ERSTRASSE

TEL 0311 · 762907 ■ TELEGR. PROPINDUS TELEX 0184057 TEL 0811 225585 TELEGR. PROPINDUS ■ TELEX 0524244

26 004/5

JOHNSON & JOHNSON New Brunswick, New Jersey, V.St.A.

Multi-layer diaper

The invention relates to multi-layer diapers *

Diapers intended for single use only or so-called disposable diapers have changed during the last Years have been introduced to an increasing extent, primarily due to the fact that they are in opposition to use diapers made of fabric or fabric, which have to be washed after soiling, conveniently. Numerous different designs of such diapers have been proposed and are in use, and some of these known diapers have been received in the market on a large scale, although they are related to their Usage properties have certain disadvantages.

With most of the known diapers, the main problem arises from the fact that it has so far proven impossible has been shown to provide a diaper which is designed to remove moisture from that surface of the diaper

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that comes into contact with the skin of a young child to avoid skin irritation and infection. There are several in U.S. Patent No. 5,612,055 Embodiments of 'diapers described, which have proven to be very effective, as aie the moisture keep them away from the skin of the toddler and as they are at the same time suitable for absorbing a full urination.

The tasks mentioned are fulfilled by a multi-layer diaper, in addition to that in the order given a support layer consisting of ^ asern in the form of a an essentially homogeneous mixture of short and long fibers that is intended to be applied to the To be brought to the skin of a toddler, also a Layer in the form of a highly porous, only loosely compacted mat made of cellulose fibers, a paper-like, highly densified cellulose fiber layer, which is covered with the only loosely compacted mat, as well as an impermeable piece of flat material, which is connected to the compacted Layer is glued within the entire contact surface. The overlay is porous and its fibers are less wettable by water than the fibers of the only loosely compacted mat, so that the liquid to it tends to escape from the support layer and into the Trespassing mat. The compacted fiber layer has a smaller mean pore size than the only loosely compacted one Mat, so that the liquid tends to preferentially condense out of the mat towards the one below Layer and not about to flow off in the direction of other parts of the surface of the mat, so that the moistening the mat is confined to an area of moderate size. The liquid entering the compacted layer tends to spread laterally due to the wicking of the layer, and the Fluid that could penetrate the compacted layer during urination if the fluid is being supplied done quickly, is made through the impermeable

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outer flat material layer retained long enough, to allow the liquid to be absorbed. The excess fluid from the compacted layer can no longer be absorbed, is through the impermeable layer in the direction of the still dry Part of the loosely compacted mat is pushed back so that the additional absorbency of the mat is used.

As in the case of the diapers according to the U.S.A. patent mentioned at the outset, the overlay layers are close by the outer surface has essentially the same amount of short cellulose fibers as in the vicinity of the inner surface, exist within the overlay itself in essentially no differences in terms of wettability, with the result that in such a diaper at least to some extent the increased wettability of the fibrous material had been used for the purpose must be to keep the urine away from the outer surface of the support layer.

Sheet materials suitable for use as Overlay for diapers according to the U.S.A. patent 5 612 055 can be made by depositing fibers are made from a stream of air »In recent times improvements have been made in this regard, like them e.g., U.S. Patent Application 108 5 ^ 6 filed Jan. 21 1971 are described. Generally speaking, includes one the procedure described there measures to remove fibers from two different types of separate devices for opening or loosening the fibers with a predetermined one Feed throughput rate, so that a predetermined total concentration in the web produced thereafter of the fibers of the two types, in order to further isolate fibers taken from the separate laser sources, to suspend the fibers taken from each source in a separate gas stream in order to move the gas streams so that that they move towards one another at least initially in order to then combine the gas streams so that they become one

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form a single carrier stream in which the fibers originating from each gas stream mix with one another, the Volume ratio between the total amount of gas and the total amount of fiber in the gaseous carrier stream at least 12000: 1, and finally the fibers carried along and separated by the common gas flow to condense in such a way that a tangle in the form of a non-woven web is created. Between values of the volume ratio the gas and fibers of over 12,000: 1, the fibers in the individual streams are sufficiently far apart removed so that when the streams are converged at an angle without any significant reduction the flow velocity occurs, the fibers contained in each stream, the fibers that meet with them Fibers can cross over, so that a non-woven product is formed, which is characterized in that a concentration at least one type of fiber is present on one side of the product which represents the total concentration and that a concentration of at least one other type of fiber on the other side of the product is present which exceeds the total concentration, with a transition zone between both sides of the product is present in such a way that the concentration of each type of fiber changes from the side on which the highest concentration of the type of fiber in question is present, gradually decreased towards the opposite side.

The invention has now created a diaper in which, on the one hand, all the advantageous Usage characteristics of the diapers according to the above called IT. S. A. Fat Entcripts have been preserved, at the same time, however, without any increase in manufacturing costs, firstly, an improved grip and therefore greater comfort for a toddler has been achieved and, secondly, within the overlay a gradually increasing degree of wettability exists so that the urine drains through the

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Support layer is conveyed through and into the mat, so that there is always a relatively dry surface that rests against the toddler's skin.

These improved performance properties are achieved according to the invention by providing a multilayer Achieved diaper, which has a water-impermeable load-bearing flat material piece in the specified order, also an intermediate layer, which is composed exclusively of short cellulose fibers, which loosely compacted within a larger portion of the mat they form and on one side of the mat are more compact that one of the supporting flat material layer adjacent paper-like skin contiguous with the mat is present, as well as one Overlay made of long fibers for textile purposes and short cellulose fibers so that the highest Concentration of the long fibers of the outer surface of the support layer is adjacent, and that the concentration of short cellulose fibers from the outer surface of the overlay towards the side adjacent to the mat gradually increasing. This concentration of the long fibers near the outer surface of the overlay gives the The diaper has a better grip and leads to greater comfort for the toddler. This concentration of Long fibers on the outside also lead to the falling out of the dust-like short cellulose fibers from the diaper is prevented or at least limited to a minimum, and that at the same time the strength of the outer part of the overlay layer increased.

The concentration of the short cellulose fibers has its highest value on the inside of the support layer, and the concentration of these short fibers preferably depends essentially on the outer surface of the overlay in the direction of its inner surface. Because the individual short cellulose fibers are more wettable than the individual long fibers, the network

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speed gradually over the entire thickness of the overlay to, essentially directly proportional to the concentration of the short cellulosic fibers. As mentioned, the presence of this wettability gradient in the overlay layer promotes the drainage of the rin through the Support layer through and to the even more wettable, non-bonded, only loosely compacted cellulose fiber part the mat. The overlay layer can be produced in this way be that it is as described in the aforementioned U.S. Patent Application 108 54-6. In the application This process traps any unpolished or compacted wood pulp particles into the interior of the diaper.

The subject matter of the invention and advantageous further details thereof are given below with reference to particular preferred embodiments explained in more detail, which are shown schematically in the drawing. It shows:

Pig. 1 shows a partially broken away perspective illustration of an embodiment of a Diaper in the flat-spread state;

Fig. 2 is an enlarged partial section along the Line 2-2 in Figure 1;

3 shows a reduced perspective illustration a diaper in the form in which it was made when it was put on the body of an infant; and

Figure 4- is a simplified schematic side view a production line for producing diapers according to FIGS. 1 to 3.

According to FIGS. 1 and 2, the illustrated diaper, denoted as a whole by 10, settles in its entirety open and spread out flat from several parts together, namely a bottom, impermeable to water rectangular piece of flat material 12, a fiber pile st he or a mat 14, which is responsible for water to a large extent

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is receptive, also has a rectangular shape, however, it is smaller than the impermeable sheet of material and is arranged in its center, as well as an uppermost one Support layer 16 made of fiber material, also rectangular in shape and the same size as the piece of flat material, which is arranged in congruence with the piece of flat material and the piece of flat material on the edge sections of the diaper contacts which protrude beyond the absorbent mat 14 at the periphery of the diaper, i.e. inside the sections 16b of the overlay layer 16 and the sections 12b of the impermeable sheet of material 12. The mat 14 has a cohesive, paper-like, in high Dimensions compacted lowermost fiber layer 18 to which at intervals distributed, parallel, thickened and also compacted sections 19 in the form of parallel strips, which extend over the entire thickness of the mat 14 extend. The highly compacted layer 18 is connected to the impermeable sheet of material 12 with the aid of strips 22 glued from adhesive essentially within the entire contact surface. The end sections 16b and 12b are connected to one another by adhesive strips 22.

In the preferred embodiment of the invention the moisture-impermeable sheet 12 is made of polyethylene, and it has a thickness of about 0.0254 mm. This piece of flat material can be smooth or to improve the handle and drapability one Embossing * According to the invention, other flexible, moisture-impermeable flat materials can also be used may be used, e.g., polyethylene terephthalate with a thickness of about 0.0127 mm.

The mat 14 consists of loosely compacted, short ones Cellulose fibers, e.g. wood pulp fibers or cotton linters or mixtures thereof, and these fibers are in a known manner primarily through between adjacent Fibers hold existing bonds together so that it is not necessary to add an adhesive. Generally

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Speaking of which, the mat 14 is a one Low bulk density, coherent web of loosely compacted cellulose fibers, preferably comminuted Wood fibers in the form of a so-called fluff.

As used herein, the term "short fibers" refers to fibers less than about 6.35 mm in length to "long fibers", "staple fibers" or "fibers for textile use" that are greater than about 6.35 mm in length and their length usually about 12.7 and 63.5 mm lies. The short fibers are considerably cheaper than the long fibers. The classification of fibers according to the Length can be performed using the Clark classification procedure described in the Examination Manual of The Technical Association of Pulp and Paper Industry (TAPPI-T235 SU64).

The paper-like, more compacted layer 18 of the mat 14 is created by having a surface of the Slightly moistened the mat and then subjecting the mat to pressure. The structure of the mat and its more compacted The layer and the process for making it are described in U.S. Patent 3,017,304. The thickened, more compacted sections 19 are produced in a manner to be described in that the Mat 14 is further compressed in the still wet state.

The overall density of the mat 14 including its more compacted layer 18 should be higher than approximately 0-07 g / cm2 and preferably between about 0.10 and about Of 15 g / cnr. These values of density apply to the Diaper in the state in which it is after its manufacture. In storage and handling the bulk or thickness of the mat increases to some extent, so that the density decreases Values.

The support layer 16 is viewed as a whole from fibers having a certain concentration.

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which mainly consists of short cellulose fiber] !, e.g. Wood pulp fibers or cotton linters are made, which are in Amounts from about 50% "to about 98% are present during the remaining fibers are textile fibers, e.g. fibers made of rayon, polyester, cellulose acetate, Nylon or the like. The short cellulose fibers such as wood pulp fibers or cotton linters are considerably cheaper than textile fibers, e.g. those made of cotton or rayon, and since the use of cheap fibers is significant Meaning, it is desirable to use as large an amount of cellulosic short fibers as can be used the required strength can be agreed.

The support layer 16 is preferably with the help a method for depositing fibers from air currents, for example using the method according to FIG U.S. patent application referred to above so that one a fiber web is obtained which has an outer surface 15 and an inner surface 17, in which the outer surface 15 thereby is characterized in that the concentration of textile or staple fibers exceeds the total concentration, and in which the inner surface 17 is characterized in that the concentration of the cellulose short fibers exceeds the total concentration. The term "area" denotes here that part of the support layer 16 which extends from an outer flat side in the thickness direction of the support layer to a depth of approximately 6.35 now extends · The transition zone »wipe the from each other facing away surfaces 15 and 17 is due to a decreasing concentration of the fiber type in question between the face where this fiber type predominates, towards the opposite face of the product marked. The outer surface 15 preferably contains a larger amount of textile fibers and a smaller amount by weight Amount of weight of short cellulose fibers compared to the total concentration of the two types of fibers, where, the different fibers are mixed together; the inner surface 17 preferably contains a greater amount by weight

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of short cellulose fibers and a smaller amount of textile fibers compared to the total concentration of both types of fibers, and here too the fibers are interrelated mixed..

The total concentration of the textile fibers within the support layer 16 can be between about 2% and about 50% vary and is preferably between about 10% and about 40%. The textile fibers can be, for example, artificial silk fibers of 1.5 denier, which are uniform length of about 38 mm are cut, but the invention is not limited to textile fibers of a certain length and also not to certain values of concentration. For example, it has been with overlay layers with a total concentration of textile fibers between about 10 and about 40 percent by weight that the concentration of the textile fibers on the outer surface 15 is about 5 to 20 percent by weight higher than the total concentration. In a certain embodiment of the support layer 16, the total of about 25 percent by weight consisted of rayon fibers and about 75 percent by weight short cellulose fibers, the concentration was of the rayon fibers on the outer surface 15 to about 35% 40%, and these textile fibers were substantially uniformly mixed with 65% to 60% cellulosic short fibers. In this embodiment, 17 rayon fibers were present on the inner surface in an amount of about 5% to 10%, and these fibers were shorter by about 95% to 90% Cellulose fibers mixed evenly.

Overlay layers which are suitable for the purposes of the invention have fabric weights in the range from about 33.9 to 165 6 / ^{m and} preferably in the range from about

ρ
59 to about 93 g / m. According to the invention it is also contemplated that one could use a fabric which has an even lower fabric weight. After its manufacture, the fiber web is treated with a binder, for example a self-crosslinking acrylic emulsion, and then

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becomes the web for the overlay layer with a wetting agent treated in order to partially eliminate the water repellency of the binding agent and to give the overlay layer the desired wettability One binder that has been used with considerable success is a latex made of one Polyäthylacrylat copolymer, which contains small amounts of acrylonitrile and a crosslinking monomer, which under the legally protected name "Hycar 2600 X 120" is available. This binder should preferably be a have low viscosity of less than 5 centipoise. In order to avoid excessive water repellency, the binder suspension becomes a surface-active one Agent, preferably an anionic surfactant, added. A typical surfactant, which has been found to be suitable is the ionic sulfonated alkyl ester, which is protected under the law Designation "Triton GR-5" is available. However, one can also use a nonionic8 surface-active one Use funds; for example, a polyoxyethylene sorbitan monolaurate, which is protected under the law Designation "Tween 20" is available as a special proven useful. In a typical application, the binder suspension is adjusted so that a proportion of dry solids is added to the fabric, based on the weight of the fabric in the range of about 4.5% to 9%, with the surfactant being from about 0.15% to about 0.30%. Layers when the only an extremely low percentage of textile fibers contain, e.g. a proportion approaching 2%, the amount of binder would be in the upper part of that Quantity range. It should be noted that the usage of said surface active agents leads to a decrease in water repellency that the short and long lasering the web is imparted by the binder which serves to bind the fibers together so that they form a coherent layer. After treatment with a wetting agent leaves the overlay layer

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the urine will seep through, but it remains wettable to a lesser extent than the mat.

The main body of the mat 14 is wettable to a significantly greater extent than the support layer 16, and the Mat strives to drain liquid from the support layer. The individual fibers of the mat are wettable to an extremely high degree because of the contact angle between of the liquid and fibers is generally less than about 15 ° and, in the optimal embodiment, is similar to zero, as in the previous one U.S. Patent is described in detail. The wicking or preferred absorbency However, the body of the mat for water is limited by the low density of the mat, which is at the capillaries leads to a large effective capillary radius between adjacent fibers.

The relative wicking between the overlay 16 and the body of the mat 14 is determined by both the Density values of the layers as well as the relative wettability of the individual fibers within each layer influenced. The overlay layer in some cases has one higher density than the body of the mat so that the overlay develops a greater wicking effect, however even in this case, the individual fibers of the mat have considerably smaller contact angles between them Liquid and the fibers on than the fibers of the overlay layer, thus reducing the effect of the difference the density is eliminated, so that there is an overall significant increase in the capillary pressure, the Soaking up the liquid runs through the body of the mat.

The more densely compressed fiber layer 18 of the mat 14 has the maximum capillary pressure, since with her the very small contact angles between the fibers of the mat with the high density, i.e. the small capillary radius, of the compressed fibers is combined.

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Place over a portion of the supporting layer 16, a urine evacuation takes moistened ^u rin a portion of the plating layer, so that it is absorbed by this layer and propagates to a limited extent, so that an approximately circular wetted zone arises as soon as the ^ τΐη the If the support layer 16 penetrates and comes into contact with the body of the mat 14, it is preferably absorbed by the body of the mat because of the increased wettability of the mat. In the body of the mat, the urine spreads so that it moistened an approximately circular zone that is slightly larger than the moistened zone of the support layer 16. As soon as the υ _Γ χ _η <ι _β η body of the mat 14 penetrates, it comes initially in contact with one or more of the bulges 19, and in doing so the urine is strongly attracted to the compacted layer 18 because of its high density, so that it is spread laterally within a much larger zone, the size of which varies according to the amount of the discharged Urine directs and spreads towards the edges of the mat. The urine is transported along the thickenings 19 considerably faster than in the transverse direction within the compacted bridge sections between the thickenings, and this has the consequence that the approximately circular zone within the initially wetted, only loosely compacted part of the mat 14 in the more compacted part 18 the mat assumes a generally oval shape.

The urine is transported relatively quickly in all directions in the compacted layer 18, since the more compacted layer extends without gaps over the entire adjacent surface of the absorbent mat. However, the thickenings 19 lead to an increase in the volumetric liquid throughput in the longitudinal direction, so that a larger amount of the urine is quickly transported in the direction of the ends of the absorbent arrangement. The bridge sections of the compacted layer between the thickenings 19 cause the liquid to be quickly drained from the initially wetted zone of the compacted layer and in contact with not yet wetted

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Thickening is brought, with the result that liquid is quickly withdrawn from the initially wetted zone and both in the longitudinal direction and in the transverse direction to substantially all parts of the compacted Layer 18 is transported.

Occasionally a significant amount of urine is evacuated, the compacted layer 18 becomes saturated and the excess urine is due to the presence of the impermeable layer 12 which is adhered to the compacted layer 18, the bond points forming an interrupted pattern within substantially the entire contact surface, caused to flow to the previously dry parts of the body of the mat 14 and finally penetrate into the previously dry parts of the support layer 16. It is noted, however, that this flow of the ^above rins takes place from the saturated densified layer from the outermost parts of the diaper from inside, so that the greater part of the supporting layer remains dry 16 until all the remaining consisting of fiber parts of the Have the diaper saturated with liquid. The thickenings 19 of the compacted layer 18 have the effect that, compared to a compacted layer of uniform thickness or a plurality of spaced compacted zones within the absorbent surface, there is a larger cross-section, and this larger cross-sectional area enables a larger volume of urine to be received. In the diaper according to the invention, a larger amount of urine can thus be stored in the compacted layer, and the tendency of the urine to flow back to the mat 14 or the support layer 16 is counteracted.

For the reasons mentioned, the compacted layer of the mat leads to an increase in the capillary pressure, so that an effort arises to quickly drain the liquid from the originally wetted zone. However, will the speed of migration of the liquid in the

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sealed layer 18 limited by the resistance of the capillary present there. The one used according to the invention composite mat 14- with the more compacted one Layer 18, which is in intimate contact with an absorbent material of lower density, leads compared to FIG the compacted layer alone or the uncompacted layer alone to an increase in the speed of migration the liquid.

It should be noted that the overlay layer 16 in the The diaper is arranged in register with the impermeable sheet material 12, and that the impermeable sheet material is not folded so that there is any edge of the fiber material overlaps. Thus, on the top of the diaper there is no part of the plastic of the layer 12 is covered so that no part of the plastic comes into direct contact with the toddler's skin when the The diaper is put on and fastened with the help of needles or tongues. A prolonged direct contact between the Plastic and a toddler's skin can cause irritation and infection, but such contact will not in the case of the disposable diapers known up to now avoided because there is an effort to achieve a good seal against the skin of the toddler. The better absorbency of the diaper according to the invention and its improved mode of action make it unnecessary to have a Part of the plastic material in contact with the skin of the To bring toddler.

The diaper according to the invention is normally folded and packaged for sale as it is in US Pat aforementioned U, S.A. patent. For this purpose, the longitudinal edges 12b and 16b of the impermeable flat material 12 and the support layer 16 are brought together with parts of the mat 14 each along a first fold line folded inwards so that the top layer of the folded part is in each case covered by a part of the moisture impermeable sheet material 12 is formed.

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Part of each of these inwardly folded sections becomes then folded outwards along a second fold line so that it covers the inwardly folded part, and that in the area of the double-folded parts, the end sections of the overlay layer 16 form the top layer. In the preferred embodiment adopts any double fold the relevant longitudinal edge of the diaper about a third of the total width of the folded diaper, so that in the In the middle there is an unfolded and not covered part of the diaper, which extends over the middle third extends the width of the diaper.

In its folded state, the diaper is held together by two small, centrally disposed adhesive spots, 16b between the H _a uptkörper the diaper and the edge portions overlying the support layer are arranged, inside each folded part of the diaper, such an adhesive patch available is. When the diaper is to be put on a toddler, the pleats on one side of each of the adhesive patches are opened and the open portion of the diaper is placed under the toddler's buttocks while the folded portion is folded up in the crotch. The final shape of the diaper is shown in perspective in FIG. 3 in a smaller scale. In one embodiment of the invention, the diaper according to FIG. 3 is provided with adhesive tongues 26, each of which is firmly connected at one end to the impermeable sheet material 12 and has a free end at which the applied adhesive is protected by a cover sheet. These topsheets are peeled off to expose the adhesive surfaces when the diaper is to be placed on an infant, as shown in Figure 3, and the free ends of the adhesive tabs are attached to the adjacent corners of the diaper.

Suitable fiber composites for the mats or pads 14 used according to the invention are made from short cellulose fibers obtained by grinding or chopping compacted wood pulp fibers, or

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made of cotton liner. The mats are first produced in such a way that the cellulose fibers are removed with the aid of air be blown onto a pad until a total weight

from about 68 to about 34-0 g / m is reached, whereupon the deposited fibers are exposed to a high pressure. The more compact, paper-like layer or Chews are created by taking an area of the mat off Cellulose fibers moistened with a fine water spray and then subjecting the moistened mat to pressure. It is believed that the formation of the densified skin on the cellulose mat is due to the fact that strong hydrogen bonds between touching Moistened fibers are created, which are similar to the bonds between the fibers in paper. By choosing accordingly the amount of moisture and pressure applied to one side of the mat, it is possible to reduce the Properties of the densified skin 18 can be varied as desired. The thickness, the density, the strength and others Properties of the compacted skin depend on the evenness with which the moisture is applied, according to the depth to which the moisture penetrates and according to the degree of compression of the fibers. If e.g. by spraying on the surface of the fiber web a

^ z ρ

Applying an amount of water of about 0.0015 cor / cm and the web

then exposed to a pressure of about 2.8 kg / cm, a suitable, compacted, cohesive, paper-like skin 18. The thickenings 19 can be erzeμgt that one the web subject to additional pressure, e.g. with the help of an embossing roller, while the web is still damp, whereby this additional pressure is preferably several times higher than the pressure applied to create the densified layer 18.

In the case of the ^ to create the mat 14 according to the invention The short fibers used are usually exclusively wood pulp fibers or cotton linters. However, you could use other cellulose fibers as well

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Mixtures of cellulose fibers and other fibers. like silk, Use wool, nylon, and cellulose acetate. In most cases of application, largely purified Kraft paper pulp fibers have been found proved to be very suitable.

The diaper according to the invention can be made with the aid of a system in Pig. 4 shown type can be produced. Here, a supply roll 41 made of compressed wood pulp is provided, from which the material for producing short cellulosic fibers is fed to a mill or grinding device 42, from which a paser stream is blown onto a conveyor belt 43 so that one layer 44 arises, which has a weight between about 68 and about 340 g / m. The layer created in this way is under a Compaction roller 46 passed, beyond which the Layer has sufficient cohesion that it can be used as a self-supporting sheet without further to be carried by the conveyor belt 43. The web then runs between two calender rolls 47 in order to continue to be compacted, whereupon the web passes under a nozzle arrangement 48 which serves to give a fine Apply moisture spray to the top of the web. Then the moistened web runs between two further calender rolls 49, which exert a high pressure on the web, around the web on its upper side a skin 51 to be provided.

The amount of moisture applied to the web can be between about 0.0005 and about 0.03 eai of water per square centimeter the web surface vary, and it depends on the desired thickness of the paper-like, stronger compacted skin; with thinner webs with a very thin paper-like skin, smaller moisture r amounts are used, while thicker webs with thicker skin use correspondingly larger amounts of liquid be used.

The pressure applied by rollers 49 can

vary between about 0.35 and about 7 kg / cm and more,

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and in practice a pressure in the range applied from about 0.7 to about 3.5 kg / cm. At a Typical embodiment is the web with water in one

7. Ο

Sprayed at an amount of about 0.0015 cnr / cm and then subjected to a pressure of about 2.8 kg / cm to produce a compacted, cohesive, paper-like skin of uniform thickness on the wetted surface of the web. The amount of moisture is selected so that the web is still moist after the skin 51 has been created. The web then passes between a carrier roller 52 and a back-up roller 53 in order to be provided with the more compacted thickenings. The roller 52 has a plurality of axial spacings distributed, extending in the circumferential direction of rib-like approaches 54-, which are supported on the previously generated H _au t 51, and there is present in the web is still residual moisture and by the lugs 54-a If increased pressure is applied, the more densely compressed thickenings are created 19

When applying pressure through the lugs 54 embossing roller 52 according to FIG. 2 also result in free hems or air gaps 20 which are in alignment with the thickenings 19. According to FIG. 2, the non-thickened ones go Parts of the compacted layer 18 on a generally flat surface 21 into the only loosely compacted mat 14 over, and the thickenings protrude upwards from the surface 21, so that they compacted into the loosely Mat 14 protrude to give the absorbent dressing a three-dimensional reinforcement.

After the skin 18 and the thickenings 19 have been created, the absorbent web comes into contact with it a web 55 made of a support material and is of this The web is carried while it is divided into individual mats 14 by a cutter 56. From a supply roll 58 from a polyethylene film 12 is supplied, on which according to FIG. 4 with the aid of a device 59 adhesive is applied in the form of strips. How on

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As described above, the adhesive is arranged in the form of parallel strips or beads 22 between the impermeable sheet material 12 and the compacted layer 18 of the mat 14 - and at the edges of the diaper between the sheet material 12 and the overlay layer 16. If necessary, the adhesive can also be arranged in the form of a gapless layer between the polyethylene material and the mat, but there is a risk that the diaper will become too rigid. It is also possible to apply the adhesive in the form of other patterns, for example in the form of spaced spots or so-called connecting islands, but it is necessary to provide a fairly firm connection between the sheet material 12 and the mat 14, and not part of the The polyethylene material should be further than about 50 mm from the next bond point. If no such connection within the entire diaper surface present, the polyethylene film from the compacted layer 18 may peel off, so that voids of significant size in which rinmengen accumulate in the form of puddles in an uncontrollable manner large ^u can.

After the support material and the polyethylene film to rest on the relevant surfaces of the absorbent Mats 14- have been brought in, the bandage is made with the help further rollers 60 and 61 compacted and brought into its final shape, whereupon of the strand thus produced the individual diapers are separated with the aid of a cutting device.

If necessary, one can omit the device 59 for applying adhesive and the connection between produce the polyethylene layer and the fiber layers by a heat seal, which with the help of a in the Production line switched on sealing device is effected.

As mentioned, the overlay layer 16 is preferred manufactured using the process that in the

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U.S.A. patent application mentioned at the outset is described. The overlay has a total concentration of short Fibers with a length of at most about 6.55 now »die is between about 50 and about 98 weight percent. the mean length of the short fibers is about 1.6 to about 4.8 mm. To make the overlay, first short cellulose fibers 70 and long lextile fibers 71 one Device 72 for loosening and mixing the fibers is supplied, which consists of two individual rotating lickerins as described in the referenced U.S. Patent Application. The fibers 70 and 71 become the Device 72 is fed at the desired speed so that that a web 73 with the desired total fiber concentration is created! / The device 72 is not only used to loosen up and loosen the fed fibers * individually, but it causes the fibers fed to it from each source in separate gas streams are suspended, which are agitated so that they combine into a single carrier stream in which the fibers from the two streams cross over to form the overlay in the manner described above to build.

The volume ratio between the gas and the fibers depends on the type and length of the fibers in each of the separate gas streams. With most of the commercially available shorter fibers suitable for use in the overlay layer according to the invention, one can work with larger values of the volume ratio compared to longer fibers or staple fibers. In the case of the shorter fibers, the volume ratio between the gas and the fibers in the separate gas streams is at least 12,000: 1 to 15,000: 1, and it can be up to 275,000: 1. In the case of the longer fibers or the textile fibers, the volume ratio between the gas and the fibers in the separate gas streams is preferably at least about 15,000: 1 to 18,000: 1 and can be up to 275,000: 1, but it is expediently between 100,000: 1 and 275,000 : 1 »The minimum value

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the volume ratio between the gas and the fibers in the total flow resulting from the partial flows to some extent according to the total concentration of the short and long fibers, and it is preferable equal to or above the aforementioned minimum test value. With volume ratios between the Gas and the fibers, which are between about 12000: 1 and about 275000: 1 in the total current, it is possible, very much uniform fiber webs as defined in said U.S.A. patent application with a high production speed that is "up to about 168 m / min or above. As mentioned, the transition is the fiber concentration between the surface 15 and the surface 17 and vice versa substantially uniformly. As used herein, the term "substantially uniformly" denotes the fact that at no point between the surfaces 15 and 17 there is practically a clearly discernible dividing line between the fibers of the nonwoven fabric is when you look at the fabric in cross section.

The fiber web 73 delivered by the device 72 can be transported to a station by a conveyor belt 74- where it is bound throughout with a binder of the type mentioned above, that of the web of a source 75 is supplied from. Beyond this station, the web 73 is dried by drying drum 76 to then guided upwards according to FIG. 4 and with the rest Parts of the diaper to be bandaged.

Expectations: 509815/0112

Claims (10)

EXPECTATIONS 1. Multi-layer winding, characterized in that a porous support layer (16) in There is a form of a non-woven web consisting of fibers with the length usual for staple fibers and short cellulose fibers consists that the total concentration of fibers with the usual length for staple fibers is about 2 to about 55 weight percent means that the total concentration of the short fibers is about 45 to about 98 weight percent is that the web has an outer flat side (15) on which the concentration of fibers with that of staple fibers usual length is higher than their total concentration that the web has an inner flat side (17) on which the Concentration of the short cellulosic fibers is higher than their total concentration, being a highly porous one, only loosely compacted mat (14) made of cellulose fibers in surface contact with the inner flat side of the support layer is arranged, and that with the outer surface of the mat a water-impermeable load-bearing flat material layer (12) is glued. 2 # diaper according to claim 1, characterized in that the length usual for staple fibers containing fibers are rayon fibers. 3. Diaper according to claim 1, characterized in that the usual for staple fibers Length fibers are polyester fibers. 4. Diaper according to claim 1, characterized in that the usual for staple fibers Length fibers are present in a total concentration of about 10 to about 40 percent by weight, and that their concentration on the outer flat side (15) 509815/0112 the overlay layer (16) by about 5 to 20 percent by weight is higher than their total concentration. 5. Multi-layer diaper, characterized in that a porous support layer (16) in Form of a non-woven web is present, which consists of the usual length of staple fibers and short fibers Cellulose fibers consist that the total concentration ■ of the fibers having the usual length for staple fibers in the overlay layer about 2 to about 55 percent by weight is that the total concentration of short fibers in the overlay layer is about 45 to about 98 percent by weight is that the web has an outer flat side (15) on which the concentration of the length usual for staple fibers containing fibers is higher than the total concentration mentioned, that the web has an inner flat side (17), at which the concentration of the short cellulose fibers is higher than the total concentration mentioned, that of the middle Part of the webs between the two flat sides has a transition such that the concentration of one in the case of staple fibers, fibers having the usual length from the outer flat side in the direction of the inner flat side gradually decreases, and that the concentration of the short cellulose fibers from the inner flat side in Gradually decreases towards the outer flat side, so that a highly porous, only loosely compacted mat (14) is made of cellulose fibers that are in surface contact with the inner flat side of the overlay layer stands, and that-with the outer surface of the mat a water-impermeable bearing flat material piece (12) is glued. 6. Diaper according to claim 5 »characterized in that the total concentration of the at Staple fibers having the usual length fibers is about 10 to about 40 percent by weight, and that these fibers are an the outer flat side (15) of the support layer (16) in one Concentration are present, which by about 5 to 20 509815/0112 weight percent higher total concentration as said ^ e. 7. Diaper according to claim 6, characterized in that the transition in each type of fibers between the flat sides (15, 17) of the support layer (16) is substantially uniform. 8. Diaper according to claim 5j, characterized in that the one common with ~ staple fibers Length fibers are rayon fibers. 9. Diaper according to claim 5 »characterized in that the one common with staple fibers Length fibers are polyester fibers. 10. Multi-layer diaper, characterized in that a .porous support layer (16) is present in the form of a non-woven web, which is made up of fibers having a normal length for staple fibers and short cellulose fibers that the total concentration consists the fibers having a normal length for staple fibers is about 2 to about 55 percent by weight, that the total short fiber concentration ranged from 45 to about 98 percent by weight that the nonwoven web has an outer flat side (15) on which a mixture of fibers having the usual length for staple fibers and short cellulose fibers is present, and at which the concentration of the length usual for staple fibers containing fibers exceeds the total concentration mentioned so that the web has an inner flat side (17) on which a mixture of short cellulose fibers and the usual length of staple fibers is present, and on which the concentration of the short Cellulose fibers exceed said total concentration that in the middle part of the web between the a transition is present on both flat sides in such a way that the concentration of that which is usual with staple fibers Length of fibers from the outer flat side 50 9 815/0112 in the direction of the inner flat side gradually, diminishes, and that the concentration of the short cellulose fibers increases from the inner flat side in the direction gradually reduced to the outer flat side that a highly porous, only loosely compacted mat (14) made of cellulose fibers is present, the layer in surface contact with the inner flat side of the support stands, and that a water-impermeable load-bearing flat material piece (12) is glued to the outer surface of the mat is. 509815/01 12 Blank page