DE2047439A1 - Disposable diaper - Google Patents

Description

PATENT ADVOCATE DR. HANS-GUNTHER EGGERT, DIPLOMA CHEMIST

5 KDLN-LINDENTHAL PETER-KINTGEN-STBASSE 2

Cologne, Sept. 25, 1970 Rö / Cl / 221 ^

Johnson & Johnson, 501 George Street, New Brunswick, New Jersey, USA

Disposable diaper

The present invention is a multi-layer disposable diaper with high absorbency, which consists of a first layer that comes into contact with the child's skin and a porous, fibrous, fleece-like, glued top layer with controllable wettability from mixed long and short stripes. This is followed by a second highly porous, loosely layered layer of cellulose that has greater wettability than the first Layer owns. A third layer connected to the second is paper-like, very dense and made of the same cellulose material like the second layer, but with a much smaller average pore size. The last layer is a water-impermeable carrier film attached to the compacted third layer with a widely divided adhesive surface adheres.

Disposable diapers have considerable advantages over those which are washed and reused, especially when not in use at home. In recent years, there have been various disposable diapers proposed, some of which have successfully established themselves in the market. But the successful disposable diapers have insufficient puncture properties, you

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Success only comes from providing consumers with the shortcomings resigned as part of the price for convenience.

One purpose that has not yet been sufficiently achieved is the desire to remove moisture from the surface of the diaper, that comes into contact with the child's skin, thereby causing irritation and infection of the skin to avoid.

Another essential point is the lack of firmness and real adaptation to the child's body for the greatest possible comfort.

According to one embodiment of a known disposable diaper Creped cellulose wadding was used as the absorbent material, covered with a permeable paper-like cover material covered on the side that comes into contact with the child's skin and impervious on the outside Possessed plastic layer. With such a bird, the cotton wool becomes more or less even with the urine of the Soaked in a considerable amount of moisture only through the thickness of the paper from the skin of the child Child is separated. During use, the weight of the child sets the paper-like layer against the soaked one Wadding is pressed so that considerable amounts of moisture come into contact with the child's skin through this layer come.

In addition, the limited absorbency of the Cellulose wadding of the known disposable diaper measures necessary to prevent the overlying clothing from becoming wet of the child or the bedding. This V / indel has a folded edge of impermeable Plastic wrap that is used to hold the urine that is

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comes into direct contact with the child's skin to produce a to form impermeable envelope. However, prolonged direct contact of the child's skin with plastic can lead to a Cause irritation and infection.

In addition, the paper-like cover material and the creped Wadding this diaper relatively hard. So that the diaper is inconvenient, especially if there is enough cotton wool to adsorb a reasonable amount of urine.

The object of the invention is therefore to produce a diaper which is sufficiently small for the child to be comfortable and the

a) collects the entire amount of urine released,

b) can handle the maximum amount of urine leakage,

c) quickly drains the urine from the child's skin as well as any relatively dry urine that is in contact with the skin Layer leaves and

d) Keep the urine absorbed away from the clothing or bed linen over the diaper.

The invention therefore relates to a multi-layer disposable spindle, which is characterized by having a fibrous layer that is in contact with the child's skin is brought, a highly porous layer in the form of a loosely layered cellulose fleece, a paper-like compressed, strongly compressed fibrous layer of cellulose material that forms a uniform layer with the loosely layered fleece Forms a whole and has a water-impermeable outer film, which is on the contact surface with the compacted Location is glued.

The top layer is made of porous material, the fibers having a lower wettability for water than the fibers

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Piping of the loosely layered fleece, so that it is effected that the liquid migrates from the top layer into the fleece. The compacted fibrous layer has a smaller one average pore size than the loosely packed web, thereby causing liquid to flow from the web into the compacted location migrates »

The corresponding elements of the multilayer diaper work together in such a way that firstly, liquids such as urine, which in a small area on the outer surface of the Top layer flows, preferably into the underlying fleece

μ than seeps into other areas of the top layer, thereby achieving will that the moistening of the top sheet to a small area restricted and the fluid is carried away from the child's skin; that second, liquid pouring into one narrow area of the loosely layered fleece penetrates, preferably from the compacted layer below than is absorbed by other areas of the web, thereby causing the wetting of the web to one The area of moderate expansion is restricted and the fluid is further removed from the child's skin; that thirdly, fluid absorbed by the compacted layer expands laterally due to its doothed action; fourth that fluid that is lost during emptying

^ (if this is strong) go through the compacted layer would like to be retained by the impermeable cover layer for sufficient time so that it can be soaked up and that fifth, excess fluid in relation to the Absorbency of the compacted layer due to the impermeable layer in the dry part of the loosely layered one Fleece flows back, making the extra absorbent Filling is exploited.

According to the preferred embodiment of the invention, the Upper class equal in size to the impermeable layer,

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so that there are no folded edges of the latter over the top layer of the diaper there. In this embodiment, the entire topsheet of the diaper is in contact with the skin of the Child brought into contact, made of fibrous material, so that no plastic material or similar impermeable Location comes into contact with the skin. Therefore, the diaper avoids clamminess and possible irritation and infection, which result from the direct contact between the plastic material and the skin.

The present invention is described below with reference to the in the illustrated embodiments explained in more detail.

Pig. Figure 1 shows a perspective view of an open unfolded Diaper according to an embodiment of the invention partially in section.

Pig. 2 shows a section of the diaper from Pig. I. along plane 2-2, showing the internal structure.

Pig. 5 and ^ are sections corresponding to the one in FIG. 2 which represent other embodiments according to the invention.

Pig. 5 is a perspective view of a diaper according to FIG Pig. 1 and 2, after being put on a child, on a smaller scale.

Fig. 6 is a perspective view showing is how the diaper of Figures 1 and 2 can be folded and partially opened for use.

Figure 7 is a longitudinal section through the diaper of Figure 6 level 7-7.

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Pig. 8 and 9 are partial perspective views, partially cut away, of various embodiments relating to the construction of the compacted layer.

Fig. IO is a simplified schematic view of the production line, on which the diaper is made.

11 is a schematic cross-section through the diaper; showing urine absorption.

Figure 12 is a graphical representation of a series of curves showing the beneficial high velocity of fluid migration obtained by using composite nonwovens with a compacted layer.

The diaper material shown in particular in FIGS 10 has, when it is completely spread out and laid flat, a water-impermeable layer on the underside 12, which is rectangular, also a highly water-absorbing fibrous absorbent pad or fleece 14, which is also rectangular but smaller than the impermeable layer 1st and centered on the last attached 1st, and one Overlying cover layer 16 made of fibrous material, which is also rectangular and the same size as the impermeable one Layer 12 possesses and adjoins this and is in contact with the diaper in the edge regions thereof, since it extends at the edge beyond the highly absorbent layer, i.e. the parts 16b and 12b of the cover layer 16 and the impermeable layer 12 are in connection with one another. The fleece 14 is paper-like compacted, strongly compressed lower fibrous layer with the impermeable film 12 through slightly bead-like Adhesive strips 22, which run essentially over the entire surface of the layer 12 facing the layer 18, run

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is stuck. The edge parts l6b and 12b are also through these adhesive strips 22 are connected to one another. To a preferred embodiment of the invention is the moisture-impermeable layer 12 made of polyethylene

mm

formed film, which has a thickness of about 0.025 /. The film can be smooth or embossed to make folding and improve the grip. However, other suitable flexible, liquid-impermeable films can also be used may be used, such as polyethylene terephthalate film with a thickness of about 0.0125 mm.

The fleece lh is formed from loosely layered short cellulose fibers, such as wood pulp fibers, cotton linters or mixtures thereof, which are primarily held together by fiber composite in a known manner, so that no additional adhesives are required. In short, this is a fleece in the form of a coherent web of loosely layered cellulose fibers with a low bulk density, preferably comminuted wood pulp fibers in the form of flakes.

As used herein, the term "short fibers" denotes Fibers that are less than 6.35 mm in length in contrast to "long" or "spinnable fibers", longer than 6.35 mm and generally one length now have between about 12.7 and 63.5. The short fibers are much cheaper than the long ones. The classification of the fibers according to length can be done using the Clark Classification Method in the testing manual of "The Technical Association of Pulp and Paper Industry (TAPPI-T233 SU6 ^) ".

The paper-like compacted layer 18 of the fleece 14 is made by slightly moistening a surface of the fleece.

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forms, after which pressure is applied. The properties of the fleece and its compacted position as well as the process for the preparation of the same is described in US Pat. No. 5,017 J504 described.

The overall density of the web 14, including the densified layer 18, should be above about 0.07 g / cm2 and preferably are between about 0.10 to 0.15 g / cnr. During storage and treatment, the cut or size increases the thickness of the fleece to a certain extent, which results in a lower density.

The topsheet 16 is made from a blend of fibers, preferably consisting of short cellulosic fibers such as cellulose fibers or cotton linters, amounts of about 75 to 98 % being used with the remainder being textile fibers such as rayon. Short cellulose fibers such as cellulose fibers or cotton linters are considerably cheaper than spinnable cellulose fibers such as cotton or rayon, so that their use reduces the costs for the top layer of the diaper.

In the upper layer are the short fibers with 2 to 25 Gew .- ^ textile fibers in an even mixture, with it ^ The textile fibers are, for example, rayon fibers with 1.5 denier and a uniform length of 38.1 mm. The short and long fibers are random and substantially uniformly distributed and interconnected by one Binders such as self-crosslinking acrylic resin emulsion tied together. The top layer is also treated with a wetting agent to partially reduce water repellency to counteract the binder and to bring the top layer to the desired degree of wettability. Upper classes with these properties are described in detail in US application serial no. 729 784.

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Topsheets suitable for the purposes of the invention have a make weight on the order of y 1 to 170 g / m and a density less than 0.15 g / cm, generally in the range between 0.05 and 0.1 g / cm- ³ . The dry strength of the topsheet for a material weighing about 51 g / cm is at least 2.68 kg / m in the machine direction and at least 1.785 kg / m in the cross direction. The structure is unusually elastic, full, soft and easy to drape compared to previously known products that have a substantial content of short fibers.

An important aspect of the invention is the provision of different wettabilities between those described above Fiber components of the diaper, so that the moisture from the topsheet into the nonwoven body and from there into it compacted layer is peeled off.

The fiber elements of the topsheet 16 of the diaper are on least wettable. Nevertheless, a certain wettability with water is also desired here. A water repellency of the topsheet is undesirable because at the desired fiber density in the topsheet it could cause the Liquid could not penetrate into the top layer and thus into the absorbent layers underneath, so that the effect a tent material that prevents the passage of rainwater. For this reason, the The topsheet is usually treated with a crosslinking agent such as an anionic surface treatment agent to protect the To mitigate and reduce water repellency imparted to the short and long fibers of the web by binders that connect them to form a coherent layer. After treatment with a crosslinking agent leaves the Urine passes through the upper layer, but remains less cross-linked than the fleece.

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A suitable parameter for wettability is the liquid-paser contact angle for the individual pasers the layer, which is almost 90 ° for fibers that are difficult to crosslink, and for fibers that are highly water-repellent exceeds 90 ° and is almost 0 for fibers that are highly wettable by water. The liquid paser contact angle can dry through boundary layer photography at high speed of individual Pipes, which are held in a clamp, are determined, with the pasers in a wetting liquid (Water) at 0.5 cm / sec. be immersed by known means.

In each individual topsheet, the liquid-fiber contact angle for the individual fibers can vary considerably due to the non-uniformity of the distribution of the water-repellent binder and the crosslinking agent. Nonetheless, an angle between about 30 and 60 degrees will provide suitable topsheet wettability for most (over 50 %) of the individual fibers in a random distribution, with an angle between about 46 and 60 degrees being preferred.

The fleece body 14 is much more wettable than the top layer, whereby a drainage of the liquid from the Upper class is effected. The individual fibers of the fleece are extremely wettable, they generally have one Liquid-fiber angle of contact below about 15 and reach 0 ° as the optimum. However, the wicking or preferred water absorption of the nonwoven body is limited by its low density, which creates a large effective capillary radius for the capillaries between adjacent fibers results.

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The pressure that causes a liquid to enter a cylindrical capillary is given by the following Expressed in the equation:

ρ - 2 ^ cos e
r

P is the capillary pressure,

/ "the surface tension of the liquid, θ is the liquid-fiber contact angle and r is the capillary radius.

For a given liquid, the pressure (capillary force) increases with the cosine of the liquid-fiber contact angle (and reaches a maximum when the angle is 0 °), and decreases with decreasing capillary radius, so that narrower capillaries will withdraw from wider liquid.

The relative wicking between the topsheet 16 and the nonwoven body 14 is determined by both the relative Densities of the layers as well as caused by the relative wettability of the individual fibers in each layer. The topsheet is sometimes denser than the nonwoven body, creating greater wicking in the topsheet could be achieved, but even then the individual fibers of the fleece have a significantly smaller one Liquid-fiber ^ contact angles than those of the Upper stratum, so that the difference in density is more than made up and an increase essentially everywhere of the capillary pressure is effected to suck liquid into the nonwoven body.

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The compacted fiber layer 18 of the fleece has a maximum of capillary pressure, since with it both the very low contact angle of the fleece fibers with the high density (small capillary radius) of the compacted fibers is combined.

Fig. 11 shows the liquid absorption of the invention Diaper. When urine is emptied into the area of the topsheet 16, it partially wets the topsheet and is absorbed in this, spreads over a limited area and forms an essentially round one humidified zone herein, which is designated in Fig. 11 with 16w and shown in dashed lines.

When the urine penetrates through the topsheet and comes into contact with the nonwoven body 14, it is preferred absorbed in the fleece body because of its greater wettability. The urine is distributed in the fleece body and wets a larger, essentially round zone, which is designated 14w and shown in dashed lines.

When the urine penetrates through the nonwoven body it comes into contact with the compacted layer 18 and is in this is strongly drawn in, because it has a higher density, is distributed laterally over a lot larger essentially round zone, which is designated by 18w and shown in dashed lines, or up to the Edge of the fleece. The latter depends on the amount of urine that penetrates.

When a certain amount of urine has been evacuated, the compacted layer may become saturated

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and the excess urine caused by the presence the water-impermeable film 12 and its adhesion to the compacted layer at various points supported, in the previously dry parts of the fleece body and finally in the previously dry Sections of the upper class invade. However, this outflow from a saturated, compacted layer takes place here from the outer portions of the diaper inwards so that most of the topsheet remains dry until all other fibrous parts of the diaper are soaked.

As already stated above, the compacted layer of the fleece has a high capillary pressure, which has the effect that Liquid is quickly withdrawn from the area of the original wetting. However, the speed is the fluid migration in the destroyed position is limited by the resistance caused by narrow capillaries will. The structure of the nonwoven body according to the invention with its compacted layer that is in close contact standing with the absorbent material of lower density provides a greater velocity of the liquid Hike as a compacted or not loosely layered layer alone.

Flg. 12 shows the increased speed of ⁴ FlUssigkeitswanderung that one of the compressed obtained by the combined effect with the loosely layered pressed position, as compared with the speeds of the liquid migration in separate layers in Fig. 12 is the path of liquid migration (on the abscissa) for such a migration for a compacted layer I, a loosely layered layer II of flakes and for a

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Combination of the two, III, plotted against time. From the figure it can be seen that a liquid needs about 9 seconds for it to migrate 5 cm if both layers are combined. In contrast, case II takes 12 seconds and case I approx. 15 seconds. If the way of fluid migration against the square root of Time is plotted, almost straight lines would result in FIG.

It is believed that the improvement in the rate of fluid migration from the interaction the dense and the loosely layered layer in the fleece due to the proximity of the two layers and the fact it is obtained that very close to the high capillary pressure generated by the dense layer, there are large capillaries of the loosely layered layer, the larger amounts of liquid with relatively low Can promote flow resistance.

In addition, there is an interaction between the compressed Non-woven layer and impermeable film 12 attached thereto. An emptying of the urine takes place usually takes place within a short time, so that the adsorption rate of the diaper in this short span of time in spite of their ultimate capacity to adsorb the amount of liquid released, and in spite of the For reasons outlined above, the relatively high absorption rate could be overused. The waterproof one The layer serves to hold the urine and to protect the bed linen and clothes from getting wet, like this that the absorbent parts of the diaper have enough time to perform their function. In addition, the un-

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permeable film as an anchor to the flaky part of the fleece against the migration of the loosely layered Pasern to protect, as the waterproof film is attached to the compacted layer with the flaky part of the fleece forms a unit, is glued over a widely distributed area.

The embodiment shown in Figure 2 is one of the simplest and most economical forms of the present Invention. However, a better effect is produced by the embodiment shown in FIG. This construction is similar to that shown in Fig. 2, except that the topsheet over the impermeable The film extends out and is folded under itself in the edge areas to make a thicker, heavier border to deliver. The underfolded part of the top layer is marked 16c and the one created by the folding Curvature denoted by l6d.

Because the topsheet 16 is of considerable strength and bulk, its fold-over at the edge of the diaper increases that Strength of the diaper and causes additional tear resistance in the event that needles are used for fastening will. In addition, this embodiment improves the balance and grip of the diaper and provides one Better fit if the diaper is put on with the edge areas in contact with the child's thighs come.

Another advantage of the embodiment shown in FIG comes from the fact that by turning over the top layer, it is brought together on the inner surface of the fold.

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is pressed and stretched on the outer surface of the curvature created by the splitting, so that the outside results in a lower density of the pleated topsheet. When the diaper with urine to the edge of the topsheet Thoroughly saturated, the urine is caused to be in the denser inner part of the fold due to the lesser The density of the outer part remains and is thus kept within the diaper.

In the two embodiments shown in FIGS. 2 and 3 (folded or unfolded) the top layer is adjacent to the impermeable film, there being no overfolding of the impermeable film, around the edge of the fibrous material. Hence there is no part of the surface that comes into contact with the child the diaper (as shown in Figs. 2 and 3) covered with some plastic material so that none Plastic material comes into direct contact with the child's skin when the diaper is removed with the help of needles, Strips or the like is applied. Continuous direct contact of the plastic material with the skin of the Child can cause irritation and infection, but has nonetheless been used on previously known diapers, The higher absorption capacity of the diaper according to the invention and its better functioning make it such Plastic-skin contact unnecessary.

In the embodiment shown in FIG. 4, there are two Nonwoven layers are attached between the topsheet 16 and the impermeable film 12, the layer 14 similar to that of Fig. 2 is provided with a compacted layer 18 and a second, larger layer 2o, the

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similar to the former, having its own condensed location. This creates a stepped cross-section generated.

When the child's weight rests on the stepped construction of Fig. 4, the loosely layered one becomes absorbent material of layers 14 and 2o causes them to be partially compressed by the weight will. Since there is a greater material thickness in the middle of the compared to the edges there is a step-shaped construction, a greater pressure exertion in the middle (u'Ad thus a greater Squeeze). This gives "'; a smaller one effective capillary radius in the middle area and off the Grünoen already mentioned above, a greater wicking effect of the more compressed middle part compared to the less compressed fringes. Pur in the event that the diaper nac.lits to catch several Is used for evacuations, the embodiment shown in FIG. 4 helps. the urine in the middle of the diaper and from the edges where it could ooze keep.

The wind / 1 according to the invention is normally folded, packed and sold. F / .g. 6 shows the diaper shown in FIG. 1 in the folded state and also in dashed lines the diaper νη a partially opened state, in that it is suitable for application to the lower part of the body and the Schen'.al of a child.

Fig. 7 is a partial section through the folded Diaper according to Fig. 6 length of the level 7-7.

As shown in Figures 6 and 7, and is the rare 109819/1112

Edges 12b and 16b of the impermeable film 12 and the Upper layer 16, together with a part of the fleece 14, is folded inwards in a first palte, with one part of the moisture-impermeable film 12c forms the top layer of the fold. This is then done again each side folded out in a second fold to cover the first folded portion and the edge portion the top layer 16d as the top layer of the double fold. In the preferred embodiment, each contains Double fold on the edges of the diaper approximately one third of the width of the folded diaper, so that approx. one third of the width of the folded diaper remains as the middle unfolded and uncovered part.

The diaper is held in this folded position by two small swabs of glue 24 placed between the main body of the diaper and the overlapping sides 16b of the topsheet are attached approximately in the middle, wherein there is a swab on each folded side of the diaper. When the diaper is put on a child the folds on one side of each of the glue pads are opened as shown in phantom in FIG is, and the open part of the diaper is placed under the buttocks of the child, while the folded part is bent up between the legs. The final

The shape of the diaper is shown in perspective on a reduced scale in FIG.

According to one embodiment of the invention shown in FIG. 6 and 6, the diaper is provided with adhesive strips 26, each with one end at the impermeable Slide 12 is attached, as well as a free

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End at which the adhesive side is provided with a protection 32 is. The latter are removed to expose the adhesive surfaces when the diaper is to be put on, such as shown in Figure 5, whereupon the free ends of the adhesive strips on the opposite edges of the diaper be attached.

In this embodiment just discussed, the coherent compacted layer 18, which is connected to the fleece body 14 over its entire surface. However can

the compacted layer also, if desired, a wide |

form distributed interrupted layer, as shown in FIGS. 8 and 9, in which the diaper in sections and shown in perspective with the impermeable sheet facing up, with a portion of that sheet removed is to show the structure of the compacted layer.

The compacted layer shown in Fig. 8 consists of parallel narrow compacted strips 18s, which in Run lengthways of the diaper and are separated by narrow uncompacted strips. The condensed The layer of Fig. 9 consists of a rectangular network 18g of compacted material in which a multitude of

small areas of undeserved material are located. ™

Compacted layers as shown in Figures 8 and 9 are compacted in the same manner as continuous Layer produced as described above, although the print is provided with a relief structure Roles is exercised, as in. The o. E. U.S. Patent j5 ol7 j5o4 is described.

Suitable fiber structures for the production of layers

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14 used in this invention are made from short cellulosic fibers made by grinding or grinding compact wood pulp fibers or cotton linters. The compact cellulose material has a moisture content of 5 to Io wt -.% (Optionally, it is easily wetted in order to bring it into this region ^ before it is subjected to the grinding operation so that the fibers produced by grinding have sufficient moisture to allow they enter into a weak inter-fibrous hydrogen bond in order to provide a certain connection for the nonwoven body.

The fleece bodies 14 are formed by first placing the slightly moistened cellulose fibers on a carrier

up to a total weight of approx. 68 to ^ 40 g / cm air laid and then the air laid fibers are strongly compressed. The low content of moisture, which can be added to the pulp material if necessary is equal to that with air inflated fibers are distributed by the grinding and the inflation and causes a weak hydrogen bond, which gives the layer a certain cohesion.

The densely layered paper-like layer is made by wetting the surface of the cellulose fleece fine spraying with water and then pressing the moistened layer together. It is believed, that the formation of the compacted layer on the cellulose layer through the formation of strong hydrogen bonds between the touching moistened

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Fibers similar to that produced between the fibers of paper. The properties of the compacted layer can be varied as desired through the precise choice of the amount of moisture that is applied to the surface of the layer and the pressure to be applied. The thickness, density, strength and other properties of the densified layer depend on the uniformity with which the moisture is applied, the depth to which it penetrates and the degree of compression of the fibers. For example, fine spraying with about 0.05 cubic centimeters of water per cm g is obtained

Fleece surface and then compressing the

Fleece with about 2.8 kg / cm a suitable compacted, contiguous paper-like layer 18 on the surface of the fleece which has been moistened.

The short fibers used to make the layers are generally entirely made of fibers Wood pulp or cotton linters. However, other cellulosic fibers such as blends of cellulosic fibers can also be used can be used with other fibers such as silk, wool, nylon, or cellulose acetate. Highly cleaned lines Kraft pulp have also been tried and found to work for most applications

are satisfactory.

The diaper according to the invention can be produced with the device shown schematically in FIG. A roll of compact wood pulp 41 is placed in a size reduction mill 42 for the production of short cellulose fibers introduced, from the mill a stream of fibers is blown onto a belt 43 as layer 44,

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which has a weight between approx. 68 to 3> 40 g / cm. The cellulose tape 41 normally has a moisture content of 5 to 10 wt .- #, if it is less is what may have been caused by prolonged exposure to dry atmosphere is to slightly moisten the belt before grinding in the mill 42, to bring the moisture content to the desired range.

In the mill 42, the cellulose ribbon is ground into individual short fibers. In a preferred embodiment, however, some of the cellulosic fibers are not completely chopped and remain bound with other fibers in small lumps, generally less than about 6.355 mm in diameter. It has been found that the presence of such small clumps of fibers in the batt body 14 provides islands of increased strength for holding the liquid. When the weight of a child on a portion of the web compresses it and causes the liquid to concentrate in the compressed portion, the presence of fiber clumps in other locations will cause the liquid to be held in those locations. Preferably to about 2 to Io wt -.% Of the fibers in the form of presence of such clumps.

The air-laid fleece layer passes a roller 46 where it is compressed and from where it has sufficient cohesion, itself as a path without to wear the carrier tape 43. The train then passes a pair of calender rolls 47 where they are further compressed and then a nozzle 48 through the liquid on the upper surface of the web fine-

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is partially sprayed on. The moistened web then passes again calender rolls 49 * which are considerable Apply pressure to the web to form a densified layer 51 on the top surface.

The amount of moisture applied to the web can range from about 0.0005 to 0.03 cubic centimeters of water per centimeter Web surface area will vary and depends on the thickness of the web and the thickness of the paper-like densified desired Layer off, with less moisture for thinner | Sheets and very thin paper-like layers and larger ones Quantities are needed for thicker webs and thicker layers.

The pressure exerted by rollers 49 can vary from about 0.35 to 7.04 and more kg / cm, with a range between 0.7 and 3.5 kg / cm being preferred. In a typical embodiment, the web with o, ool5 enr ⁵ cm water surface of the web is sprayed and subjected to a pressure of about 2.8l kg / cm ^2, to a densified coherent paper-like layer to obtain on the wetted surface of the web.

Weak hydrogen bonds exist in the absorbent sheet and in the non-woven fabrics cut from it provide sufficient strength to maintain cohesion under normal handling, whereas in The condensed layer of strong hydrogen bonds exist to create the bond between the two different ones Enlarge layers of fleece. After the densified layer is formed, the absorbent tape is in contact with a tape of topsheet material 52 brought and transported further, whereby it is through a

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-ab cutting device 53 is cut into individual pieces 14. The topsheet material, which is prepared as described below, is fed by a roller 5 ^.

A polyethylene film 12 is fed from a roll 56, with strips of adhesive passing through a device 57 be applied. As already described above, the adhesive is in the form of parallel strips or beads between the impermeable film and the compressed layer, or the topsheet in the edge zones of the diaper applied. The adhesive can, if desired, as a continuous layer between the polyethylene and the Fleece can be used, but this causes excessive rigidity. The glue can but also in other forms, for example as separate points or in so-called "island connections" can be used, but there is a fairly closed bond between the Foil and the fleece required, with no part of the polyethylene foil more than about 5 * 08 cm from a bond point should be removed. If this is not the case, the polyethylene film can be compressed from the Layer can be removed, which can create rather large spaces in which there are uncontrollably large A lot of free liquid urine can accumulate.

After the topsheet material and the polyethylene with the corresponding surfaces of the absorbent fleece are brought into contact, the whole is compressed by rollers 58 and 59 to form the diaper bandage to form, after which the individual diapers of

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a cutting device 6l are cut off.

If desired, the glue applicator can be avoided and the connection between the polyethylene film and the fiber layer by heat welding effected., with a suitable welding device Can be used on the production line.

The top layer contains 75 to 98 wt -.% Short fibers, which do not extend mm over a length of 6.55. On average, the short fibers are about 1.59 to 4.76 mm long. The upper class is initially Ä

by forming a web of randomly laid dry short and long fibers in the desired Mixture prepared, this sheet having a density of about 0.09 to 0.025 g / cm ^ according to ASTM method D-1777 measured at o, oll2o kg / cm.

The upper layers weighing between about ^> k and

170 g / m 2 are generally suitable for the purposes of the invention. In particular, a top layer has been found to be suitable which consists of approximately 15 % spinnable fibers such as rayon fibers with a uniform staple length of 5.8 l cm by 1.5 Dinier and 85 % short fiber content of cotton linters. This topsheet is produced on a web laying machine with a weight of 68 g / m. This layer is then placed in a binder applicator which is provided with a suction device and a binder such as self-crosslinking acrylic acid emulsion is applied. One binder that has been used successfully is a latex of a poly (ethyl acrylate) copolymer containing small amounts of acrylonitrile and a crosslinking monomer and under

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the trade name jJiHYCAR 26ooX12o is sold. The binder should preferably have a low viscosity, which is less than 5 cP.

In order to avoid water repellency, a surface treatment agent, preferably anionic, is also used Type, added to the binder suspension. A typical surface treatment agent that proves to be suitable is ionic sulfonated alkyl ester sold under the tradename Triton GR-5 will.

The composition of the binder suspension and the suction at the suction slot is made so that the material receives a solid dry additive of 6 %, based on the weight of the material, of which about 0.15% is stirred by the surface treatment agent. A suitable range for the binder is about 4.5 to 9; J> based on the weight of the material.

Thereafter, the wet web is transferred to a drying oven, which has a temperature of 154 to 160 ° C, where it dried and the resin binder is cured. The resulting material has a density of 0.05 to ° * ° 7 g / cnr and a dry strength of about 25 kp / m in the transverse direction. The wet strength is about 16.07 kgf / m in the machine direction and about 98 kg / m in the transverse direction.

The binder in the topsheet tends to be a layer with greater dimensional stability than the nonwoven body that does not contain any binding agents. When the diaper is moistened with urine and the weight of the child on part of it, both the upper

109819/1112

The layer as well as the fleece body are compressed under this weight, but the fleece body suffers one greater compression because it does not contain any binding agent. This increased compression of the fleece body increases the wicking effect of the edge, which is usually comparable to that of the top layer (even when dry and uncompressed), and tends to move the fluid from migrating into the To keep the upper layer where it could wet the child's skin.

If desired, the top layer can be made with long pasers be laminated on one or both sides, this in place of or in addition to the short pasers mixed long pasers occurs. Such is disclosed in the above-mentioned US application Ser. 729 78 ^ described.

According to another embodiment, the topsheet can be made essentially entirely from spinnable fibers which are bonded together by a resinous binder. This allows an upper class with

greater strength can be produced, but it will a

not preferred because it is more expensive and because the strength of the topsheet material containing short fibers, is sufficient for most cases.

In all embodiments, the adhesive is impermeable Layer with the compacted, continuous or interrupted, essentially over the entire Inner surface between these two layers important because

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this avoids a separation between the two and the formation of essential gaps in which free-flowing urine could collect. ■ The adhesion of the impermeable layer to the paper-like, The compacted cellulose layer ensures that the compacted layer is dimensionally stable against transverse displacements and thereby brings about a stabilization of the loosely layered fiber flock part of the fleece layer, because the paper-like compacted layer forms a unit with the flock part of the fleece and holding forces of the spatially stable impermeable layer over the widely distributed adhesive on the compacted layer. and then is transferred to the flakes.

109819/1112

Claims (19)

Claims 1. Multi-layer diaper, characterized by a porous top layer (l6) in the form of a water-wettable web of mixed long and short fibers, a highly porous, loosely layered fleece (14) made of cellulose fibers, which lies against the top layer (l6) and opposite water has a higher wettability than this, a paper-like densified layer of cellulosic fibers (18) with a relatively high wettability and just such Plüssigkeitsfest- * entertainment assets, located with the above ™ loosely layered fleece (14) forms a unit, and a water-impermeable carrier film (12), which is attached to the compacted layer (18). 2. Diaper according to claim 1, characterized in that the carrier film (12) and the top layer (l6) are substantially rectangular and of the same size, the fleece (14) is substantially rectangular and smaller than the carrier film (12) and the top layer (ΐβ) and is arranged centered on this, so that edge parts of the diaper are formed in which the carrier film (12) and the topsheet (16) touch each other directly. \ 3. Diaper according to claim 1 or 2, characterized in that the content of short fibers that have a staple length of less than 6.35 mm, in the upper layer (16) is about 75 to 98 wt .- ^ and the rest 2 to 25 wt .- ^ formed from spinnable fibers that have a stack length of about 12.7 to 63 * 5 mm own. 109819/1112 4. Diaper according to one of claims to 3, characterized in that that the fibers of the top layer (16) by a water-repellent polymer binder are connected to each other and coated with a surface treatment agent. 5. Diaper according to one of claims 1 to 4, characterized in that that the fleece (14, 18) with the carrier film (12) distributed discontinuously by a Adhesive is bonded to the entire contact surface. 6. Diaper according to one of claims 1 to 5> characterized in that the top layer (16) has a manufacturing weight of approximately 34 to 170 g / m 2 and a density of less than 0.15 g / cnr. 7. Diaper naoh claim 6, characterized in that the density is between about 0.05 and 0.1 g / cm3. 8. Diaper according to one of claims 1 to 7, characterized in that the fleece together with the compressed layer (14, 18) has a density between about 0.07 and 0.2 g / cm ^, 9. Diaper according to one of claims 1 to 8, characterized in that the compressed layer (18) is contiguous and covers the inner surface of the fleece (l4) which is opposite the surface, which is in contact with the upper layer (16). 10. Diaper according to one of claims 1 to 9, characterized in that that the compacted layer (18) has an un- tÖ9818 / 1112 terbroehene, over the inner surface of the fleece (l4) is widely distributed layer, which is attached to the Upper layer (16) facing away from the surface of the fleece is located. 11. Diaper according to claim 10, characterized in that the interrupted compacted layer (18) consists of parallel narrow compacted strips (18s) separated by narrow uncompacted strips. 12. Diaper according to claim 10, characterized in that j the interrupted compacted layer (18) consists of a network (18g) of compacted material, in which there is a multitude of small areas of uncompacted material. 13. Diaper according to one of claims 2 to 12, characterized in that that the top layer (16) has twice the thickness in the edge areas. 14. Diaper according to one of claims 2 to 1J>, characterized in that an additional fleece (20) which is larger than the fleece (14) is attached between the latter and the carrier film (12). ^ 15. Diaper according to one of claims 1 to 14, characterized in that at least 50 % of the individual fibers of the topsheet (16) have a liquid-fiber contact angle with respect to water of between about 30 and 60 °. 16. Diaper according to one of claims 1 to 15, characterized in that the individual fibers of the cellular 109819/1112 - 52 - loose fleece (14) has a liquid-fiber contact angle with respect to water which is not greater than is about 15 °. 17. Diaper according to one of claims 1 to 1β, characterized in that the fleece (14) between the loosely layered fibers contains randomly distributed lumps of fibers, the diameter of which is not greater than about 6.35 rom and in an amount of about 2 to 10 % of the weight of the loosely layered fleece is present. 18. Diaper according to one of claims 1 to YJ, characterized in that the water-impermeable film (12) is attached to the compressed layer (18) by heat sealing. 19. The method for producing a diaper according to one of claims 1 to 18, characterized in that that the surface of a highly porous, loosely layered layer of short cellulose fibers moisturizes, the layer is compressed to form a densified layer, creating an absorbent Nonwoven fabric is formed, a water-repellent binder and a surface treatment agent used to treat a fiber layer made from an even mixture of short and long fibers and then drying the sheet to form a topsheet, which is first formed absorbent fleece between the top layer and a water-impermeable carrier film with the compacted layer is placed against the carrier film and the compacted layer with the carrier film is glued or welded. 109819/1 1 1? Blank page