DE2439367A1 - SUCTIONAL DEVICE - Google Patents

Description

ALFRED HOEPPENER _ie .

DR. JUR. DI ³ L-CHEM H.-J. WOUP ^{1J) t Au} 9 1974

DR. JUR, HANS CHR. AX

Μβ FKANKFUKr AM MAlN-HOCtm

AOBflNSKASSiM

Our No. 19! »52

The Procter & Gamble Company Cincinnati, Ohio, V.St.A.

Absorbent device

The present invention belongs to the field of absorbent devices, such as disposable diapers, sanitary napkins, Insert cushions and disposable bed pads, and particularly relates to a rear one Layer for such devices, which prevents the passage of liquids and at the same time the passage of Gases enabled.

Absorbent executions, such as diapers, are everyone known. These devices are used to absorb and retain body fluids. It it is well known to cover the exterior of these devices with a flexible plastic layer, which is intended to prevent the absorbed liquid from passing through the ugly facility intrudes and neighboring items of clothing or bed linen is dirty. The previously known, waterproof plastic layers prevent penetration of the liquid and help store the liquid in the absorbent device. But they also have an effect.

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-Z-

The absorbent device feels hot and uncomfortable wear and can even cause a rash or irritation. The known layers also prevent the absorbent from drying out Facility created by the evaporation of the contained therein Liquid can be achieved.

Gas-permeable rear layers for absorbent devices belong to the known state of the art. The purpose of these layers is to create a connection between the inside and the outside of the absorbent device and thereby enable circulation. For example, in US Patent 2,570 ¹ OIl is proposed to solve the problem of a gas-permeable back layer for aaugfähige devices with a diaper having an absorbent and a retentive part. The reluctant part is one. chemically treated rapier or cloth which is folded on the surface of the diaper and which, because of the chemical treatment, is supposed to prevent the penetration of urine.

Also in US Pat. No. 3,156,242 is an absorbent device described, which contains an absorbent body which is covered with a non-absorbent, flexible film is. The film is air-permeable and therefore allows the absorbent body arranged underneath to dry. The air permeability of the film is made possible by micropores or holes or slots reached.

In US Pat. No. 2,119,610 a combination is described which consists of a removable, disposable, absorbent pad and a holder provided for this purpose consists. The holder is made of a perforated layer

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BATH ORIGINAL

Made of rubber or Japanese silk, and the upholstery contains a perforated base made of cheap, moisture-proof material, such as cellophane, the Holder is arranged adjacent.

In deia US Patent 3,439,678 baby pants are described which are intended to be worn over diapers, the latter from a folded, waterproof fabric. The fabric contains at least two layers, each of which is woven, is waterproof and permeable to air and steam.

Other web-like, porous, thermoplastic materials are, for example, in U.S. Patents 2,027,810 and 3,292,619 and 3M26,754 and 3,446,208.

Lu is therefore the aim of the present invention, a rear Specify layer for an absorbent body which is well permeable for gases and vapors and for liquids is impermeable.

Ls is another object of the present invention, a specify the back layer for an absorbent body, which is then practically impermeable to liquids remains when the absorbent body is exposed to pressure.

It is yet another object of the present invention to provide a backsheet comprised of two relatively highly porous ones

Layers is composed.

And it is also an object of the present invention to provide a liquid impermeable and gas permeable specify the back layer for an absorbent body,

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BATH

which is economical and easy to manufacture.

According to the invention, these goals are achieved with an absorbent Device that is intended for disposal after use and at least one absorbent body and one contains backing layer, which is characterized in that the backing layer is liquid-impermeable and is gas-permeable and consists of two adjacent, hydrophobic layers, of which the first layer is liquid-permeable and has only a small proportion of void space in the total volume and the second layer is liquid-permeable and has a high proportion of void space in the total volume and the combination of these two layers creates the passage of liquid, but allows the passage of gases and vapors.

The new absorbent device is particularly advantageous when the liquid contained in an absorbent body shielded from neighboring items of clothing, formed a cooler shell and while wearing d: u? Drying the absorbent body should be made possible.

The invention is described below with the aid of the figures using a few preferred exemplary embodiments. In the Figures, the thickness of some materials is drawn greatly enlarged for better representation.

Fig. 1 shows the perspective view of what is seen as a preferred embodiment of the present invention Disposable diaper in the unfolded state, in which some layers have been partially cut away.

Fig. 2 shows the perspective view of a heavily

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major part of the backsheet of the disposable diaper shown in FIG.

Fig. 3 shows the perspective view of an embodiment of the device for perforating a moisture-proof, band-shaped material.

Although the invention will be described in terms of a disposable diaper, it should be understood that it does not apply to this embodiment is limited.

The in Fig. 1 as a preferred embodiment of the present Disposable diaper 21 shown in the invention is made from the usual variety of layers of different materials. The disposable diaper shown includes a topsheet 22, an absorbent body 23 and a backsheet, which consists of a first layer 24 and a second layer 25 consists.

The absorbent body 23 lies on the back layer and the cover sheet 22 on the absorbent body 23. Preferably the cover layer 22 is longer in the longitudinal direction than the absorbent body 23, so that it is around and under the longitudinal ends of the absorbent body can be folded as shown in FIG. Further the absorbent body 23 and the cover layer 22 are usually in the region of and parallel to the lateral edges and / or longitudinal ends on the back layer, which in the The embodiment according to FIG. 1 is formed by the first layer 24 is attached. It is of course also possible to use the absorbent To attach the body and the cover layer to the back layer on the entire contact surface.

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Any of the already known cover layers can be used as the cover layer 22. For example, the one in the • US Patent Reissue No. 26 * 151, which consists of artificial silk, which is combined with a thermoplastic binder to form a hydrophobic, sheet-like non-woven material is bound.

Also, the absorbent body 23 can be made from any of the materials well known to any person good moisture-absorbing properties. Various examples of such absorbent materials are described in the latter patent, for example multiple layers of creped tissue paper or Tissue material, cotton wool, cellulose ground, airfiiz, more absorbent, natural sponge and synthetic, foamed, absorbent materials.

The trained in accordance with the present invention The back layer contains a first layer 24 and a second layer 25. In the embodiment shown, there is the first layer 24 made of a perforated, hydrophobic, tape-like material made of polyethylene and the second layer 25 made of a hydrophobic, porous, creped tissue paper or tissue material. Each of these layers is for liquids in itself permeable. In contrast, the layers stacked on top of one another form a layer that is impermeable to liquids. Although in the embodiment shown in FIG. 1, the first layer 24 is arranged on the outside of the second layer 25 is, the second layer 25 can be arranged on the outside of the first layer 24.

The first layer 24 usually consists of a flexible, liquid-impermeable, band-shaped material,

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which has been perforated so that it becomes permeable for liquids. In the described embodiment polyethylene is used for the first layer. It goes without saying, however, that this layer can also be made from a different material v / can earth. In a preferred embodiment, the first layer 24 consists of a tape-shaped polyethylene material 46 jum thick, manufactured by Edison Plastic Inc., Metuchen, N.J. and manufactured as Alathon 3120 resin supplied by E.I. Du Pont de Nemours & Co. The tape-shaped material is perforated, as will be described below.

Furthermore, the first layer 24 has only a small proportion Cavities, which are also discussed in detail below to be discribed. The volume of the cavities produced by the perforation in the first layer is practically the same the percentage of area opened by perforating the sheet, based on the projected perforating diameters is calculated as will be described below. The area of the first opened by the perforation Layer is usually in a range of about 0.01 to about 5.0 the nominal area of the imperforate ribbon-shaped Material, preferably between 0.01 to 2.0% and most preferably between 0.01 to 1.0%. The middle one, projected The diameter of the perforations is usually between 10 and 300 µm, preferably 10 to 200 µm the most preferred embodiment 10 to 100 jam.

The second layer 25 of the embodiment described consists of a creped tissue paper or tissue product, i. made of a fibrous, band-shaped material with a high Proportion of voids in the volume, which material is made hydrophobic by impregnating with a paraffin wax,

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as is to be described in the following. The porosity of the second layer 24 is also after impregnation with the paraffin wax still very high.

In the diaper shown in FIG. 1, the circumference of the first layer 24 is greater than that of the absorbent body 23 and forms in the longitudinal direction and in the transverse direction extending edges 26 and 27. The lateral edges 27 are on the Upper side of the absorbent body 23 is folded and form so-called "side flaps". These side flaps can be attached to the Cover layer 22 are attached. Further, before the diaper 21 is put on a child, the lengthwise direction The edges 26 lying on the diaper are folded around and on top of the absorbent body 23. The overfolding the lateral and longitudinal edges can be advantageous because it allows the »eye-able body 23 is enclosed in a container formed by the first layer 24.

In the embodiment shown in FIG. 1, practically the entire first layer 24 is perforated. But it is also possible to limit the perforation to the "effective, gas-permeable part" of the backing layer. As more effective, The gas-permeable part is considered to be that part in which the first layer 24 and the second layer 25 cooperate in order to to prevent the passage of liquid and to allow the passage of gases. In the one shown in FIG Embodiment, the entire, rear surface can be referred to as an effective, gas-permeable part of the diaper, because the two layers cooperate over this entire surface. If, on the other hand, the second layer covers the entire back of the diaper, but only one in the geometric center the first layer 24 arranged, circular part with

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is perforated with a diameter of 50.8 mm, the active, gas-permeable part is also perforated on this Partly limited because this is the only part of the first ply 24 that interacts with the second ply in the intended manner cooperates.

The lateral edges 27 and 26 of the first layer 24 lying in the longitudinal direction can also be used, as shown in FIG. 1 may be perforated, although this does not affect the gas permeability of the backing layer.

The diaper 21 shown in Figure 1 can be fastened using any of the fastening means known to those skilled in the art, such as, for example a diaper needle attached to a child. Another fastener that is increasing in scope used is arnjo made from contact adhesive tape. Hino A corresponding embodiment is described in the aforementioned US patent Reissue No. 26,151. These fastening devices are not shown in the figures.

FIG. 2 shows a greatly enlarged part of the first layer 24 with the material made from the band-like material mentioned above Polyethylene arranged, typical protuberances 29, in which perforations 30 are arranged.

To produce the protuberances and perforations can advantageously the device shown in Fig. 3 can be used. The device contains two steel rollers, one pressure roller 31 and the perforating roller 32, which are arranged in frames and bearings (not shown) and form a roller gap. The roller bearings can be adjusted with the help of compressed air cylinders, whose working pressure is adjustable with a pressure control valve known to anyone skilled in the art, shifted and thereby the.

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Width of the nip 36 can be changed. In a practically used device, the perforating roller 32 was included a card cover 33 made by Howard Bros. Mfg. Co., Auburn, Mass., Is spirally wrapped. Of the Card cover 33 contains four layers of cotton fabric impregnated with an adhesive made on the basis of rubber are. The band-shaped card cover is 3.17 mm thick and 39.7 mm wide. Are in the card cover Pins or mandrels 34 are used, which are perpendicular to the plane formed by the tape and a uniform, straight

Form a linear pattern with 82 thorns per cm area. The mandrels 34 are made of tempered carbon steel with a

Tensile modulus from 18'278 to 20'387 kp / cm and have a round Cross section with a diameter of 228 µm. The ends of the mandrels extended 3.17 mm above the surface of the tape so that the total thickness of the carding cover is 6.35 mm.

The perforating roller 32 around which the carding cover was wound had a diameter of 76.2 mm and a length of more than 482 mm and was indicated in FIG. 3 by the arrow Direction driven.

The pressure roller 31 was made of a needle punched felt tubular felt sleeve 35 as manufactured by Rontex America Inc., Lowell, Massachusetts. The fibers used for this felt consist of a small one Share of polyester and a larger share of nylon staple fibers with great toughness, a fineness in the range from 1.5 to 6.0 denier and a length from 25.4 to 50.8 mm. The thickness of the felt sleeve 35 measured in the radial direction was b.35 now, the inside diameter was 7b, 2 now and the weight of the felt sleeve was 87 g per 9.3 dm of the inner surface

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before. The diameter of the pressure roller 31 wit more drawn Felt sleeve 35 was 88.9 mm. The pressure roller 31 was not driven.

Lin tape 28 made of the polyethylene film described above,

whose surface area corresponded to about 31.8 m per kg of weight, was passed through the nip 36, the effective pressure in the nip · approx. 1.7 kp per linear mm and the feed was approx. 67 m per minute.

The height of the protrusions 29 formed in the above-described manner in the said band above the surface of tape 28 ranged between about 50 to 150 jams. One the preferred height is about 150 µm, which corresponds to about three times the thickness of the imperforate tape and with what an unloaded thickness of the first layer 24 can be achieved which is approximately four times the thickness of the imperforate tape is equivalent to.

The perforations 30 have a theoretical diameter of about 226 μm , which corresponds to the dimension of the mandrels in the card cover. The term diameter of the perforation is used here for the mean value of the straight line running through the center of the perforation. The projected diameter of the perforation, that is the diameter of the perforation 30 after projection onto the Mmmip determined by the tape 28, is less than 228 inn, because the perforations are generally arranged in the side surfaces of the protuberances 29 and therefore make an angle with that of include the tape at a certain level. In addition, because of the elasticity of the film, the diameter of the perforations contracts as soon as the mandrels 34 of the card cover are withdrawn from the perforations.

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A perforated Edison film had the following properties, the knife methods of which will be described later.

Diameter of

0.1 mm perforation

3

Air permeability 3.9 cm / sec / cm with a pressure difference corresponding to 10 cm water column

Elmendorf crack resistance MD-3 6

(Values for 4 layers or CD-46 4-fold folded material)

Ball drop test 39.4 cm

Mean projected diameter of the perforation 55 / in

Percentage of perforated protuberances 8%

Elasticity measured as permanent elongation after

a) 30% elongation MD-3.3%

CD-4.5%

b) 55% elongation MD-IO, 5%

CD-IO, 0%

Tensile strength at

a) 30% elongation MD-29 g / mm Jircite

CD-20.3 / mm width

b) 55% elongation MD-34.6 g / mm width

CD-22.5 g / mm width

c) when torn MD-43.5 g / mm width

CD-25.2 g / mm width

(projected) open area 0.014%

MD = machine direction

DC = across the machine direction

The first layer 24 should be permanent after being stretched by 30% Deformation of 15% or less and a permeability

3

for air from 0.5 to 10 cm per second per cm with one

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lit »■

Have a pressure difference of 10 cm water column.

In the embodiment described, a creped, moisture-proof, white tissue paper was used as the second layer 25 or tissue product is used which has been rendered hydrophobic by treating the fiber surface with paraffin wax was. The tissue product treated with the wax retained a high porosity.

The tissue paper or tissue product was made from bleached, chemically processed wood pulp. This contained 30% bleached sulphite pulp obtained from aspen species and 70% bleached pulp suitable for the manufacture of kraft paper Wood pulp made from northern spruce and pine species. The pulp was cleaned and then with a moistureproof Resin treated, for example with Parez 631NC (American Cyanamide Company) until the solids content of the Resin V2 was% to 1% of the weight of the dry fibers. This wood pulp was made on a Yankee Fourdrinier paper machine with facilities known in the industry Processed into rolls of white creped tissue. The percentage of creping that results from the relationship: (Machine speed - roll winding speed) : The machine speed is determined to be 14%.

The tissue prepared as described was then subjected to a dry wax process * The process was carried out by The Crystal Tissue Company, Tiiddletown, Ohio _f . It has long been known and is widely used. In this process, paraffin wax, the purity of which corresponds to the regulations applicable to foodstuffs and which has a melting point of around 77.8 ° C, is used.

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points against a surface of at a speed
applied from about 286 m per minute rapidly moving tissue bands. A relatively slowly rotating heated one is used for this purpose
Application roller used, the speed of rotation of which is about 5% of the belt speed and which is partially in a
Bath dipped from the melted paraffin wax. So that the wax stripped from the surface of the application roller onto the tissue wets the surface of all fibers until all fibers
are coated, the band coated with the wax becomes
guided over additional heating rollers and then at
a temperature that is above the melting point of the wax, rolled up. In this dry wax process, the surface of the fibers within the tissue is coated with wax. The amount of wax used is limited in such a way that
that only the smallest voids between the fibers are clogged and only a relatively small reduction in the air permeability of the tissue product occurs.

A second layer 25 produced in the manner described
had the following physical properties before and after their training, the measurement method of which will be described below
will.

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Basic thickness * Tensile strength (now) speed in (g / m ² ) dry

Condition (pd / mm
Broad)

Tensile strength when wet (pd / nun
Broad)

CD

MD 'CD MD

waxes 395 0.127 26 9.5 - 2.95

waxed 483 0.127 28.4 9.7 7.4 3.15

2 * measured at a pressure of 12.4 pd / cm

HD = machine direction

CD = across the machine direction

Air permeability with a pressure difference corresponding to 12.7 ran water column (dm ³ / min / dm ² )

306

274

The wax-treated tissue product described above had a void fraction of the total volume of 88%. The for the calculation method used to determine the void volume is described below. The void volume the second layer 25 should be at least 60% of the total volume. The layer used with the high proportion of void volume should have a permeability for air that corresponds to a pressure difference of 12.7 mm water column

2
is at least 30 liters / min / dm.

Another type of process was used to make the tissue product hydrophobic. With this other one Procedure was paraffin wax in a chloroethylene solvent dissolved, the solution having about 5% by volume of paraffin wax. The tissue product became through this paraffin solution guided and carefully wetted. The wetted tissue product was then removed by evaporation of the solvent dried.

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The second layer 25 can also be produced by only the bottom surface of one having a large proportion of voids absorbent body is treated with one of the hydrophobic materials mentioned above, for example, so that only the bottom layer of the absorbent body is hydrophobic up to a depth corresponding to several fiber lengths will.

About the impermeability to liquids and the permeability For gases of the back layer, the test cushion layers described in the following examples were used manufactured. All of the test cushion layers were approximately the same dimensions, they were square with one Side length of about 10 cm and had several layers. The first four layers of each layer of upholstery were similar and had the following order. The first L.; ujo, which the diaper topsheet 22 was a Kendall Webline 6211 non-woven product having a basis weight of

2
23.9 g / m available from Kendali Corporation.

The second layer was made of a creped, moisture resistant Tissue made from a material suitable for making bleached Kraft paper and had a

2
Basic weight of 19.9 g / m. The third layer consisted of cellulose flakes or, as they are sometimes also called, air felt, which were made of bleached material made from soft wood and suitable for Kraft paper. This third layer had a basis weight of 168 g / m. The fourth layer consisted of creped tissue, a material suitable for bleached Kraft paper

2 with a basis weight of 19.9 g / m. The layers 2, 3 and 4 corresponded to the absorbent body 23 in FIG. 1 shown diaper. The different upholstery layers used for the test only had different, backwarming

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term layers, which are described in the individual examples.

The cushion layers used for the test were with a test liquid which is used to simulate urine was provided and consisted of a 1% aqueous NaCl solution, whose surface tension was achieved by adding Triton X-IOO, a surfactant made by the Röhm and Haas Company, Philadelphia, Pennsylvania, was reduced to 45 dynes / cm. Each. Cushion layer was with the test liquid wetted, the degree of wetting about 5 g of liquid per 1 g of absorbent body, i.e. per gram of the combined weight of layers 2, 3 and 4. This degree of wetting is referred to below as "wetted up to 5X".

The liquid impermeability of the back layer was determined by a permeability test to be described below certainly. The gas permeability of the rear layer was determined by a method which will also be described later Evaporation test determined.

Permeability test. Two coats of Whatman No. 4 filter paper, available from W. & R. Baiston Ltd., England, were weighed to determine the dry weight of the filter paper to determine. The back layer of a wetted cushioning layer was in contact with the filter paper brought. On the moistened cushion layer was then with With the help of a pressure stamp with a diameter of 5 cm, which is located in the middle of the one opposite the back layer The outer surface of the cushioning layer acted and a pressure of 35.2 or 70.4 pd / cm was exerted for 15 minutes. After 15 minutes the filter paper was weighed again,

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to determine its weight when moistened. The amount of liquid absorbed by the filter paper was then determined by subtracting the weight of the dry filter paper from the weight of the wet filter paper became. In order to obtain a measure of the liquid permeability of the backing layer, the amount of Liquid determined per unit area which had penetrated through the backing layer under pressure. For this purpose the Amount of fluid that has leaked through the rear layer

2 strength due to the area under pressure, i.e. 19.7 cm,

divided.

Evaporation test. The cushion layers were up to about 5X wetted and "covered" with a non-perforated polyethylene film. To do this, the film was placed over the top layer the cushioning layer and folded lightly around its edges. The parts of the foil that were wrapped around the edges were attached to the backing sheet with commercially available polyester tape.

The free rear surface, i.e. not covered by the film, was practically square with a side length of about 9 cm. The covered, wetted cushion layer was then weighed to provide a first layer weight. The upholstery layer was then placed on a laboratory bench with the back layer up, around the uncovered back Exposing the layer to ambient room conditions, which were about 22 to 23.8 ° C and 60% relative humidity. The cushion sheet was exposed to these conditions for about 3 hours and then reweighed to remove gain second layer weight. The weight loss achieved by evaporation was calculated by subtracting the second Layer weight determined by the first layer weight. Of the

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Evaporation loss was converted into an evaporation rate by dividing the weight loss over the treatment time and the free area of the back layer was divided. This factor was then converted to one Specify the evaporation rate expressible in grams per 1000 cm per hour.

Examples I - IV

To produce test cushion layers, the four first layers described above were also applied to a single layer of the above-described, perforated, tape-shaped polyethylene film laid. The polyethylene film was on the Position 4, and the protuberances 29 were against the inside of the Upholstery layer directed. The cushion layer was then using the test liquid is moistened up to about 5X. The one after that The moisture permeability and evaporation tests carried out resulted in those given in Table 1 below Results.

Examples V - VIII

To produce further test cushion layers, the four first layers described above on a single layer of the one also described above, treated with paraffin wax TissuG product placed so that the wax treated Tissue product was in contact with layer 4 of the cushioning layer. The cushion layer was with the test liquid up to about 5X moistened. The results of the moisture permeability and evaporation test performed thereafter are given in Table 1 below.

Examples IX - XII

Test cushion layers were made which correspond to the above contained four first layers and a reverse

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term layer, which consists of a layer of the above, with Paraffin wax treated tissue product and a layer of the perforated polyethylene film also described above passed. The tissue product treated with wax was in contact with layer 4 of the cushioning layer, as shown in FIG. 1 for the layer 25 of the diaper 21 is shown. The perforated polyethylene film was against the wax treated tissue product on, corresponding to the outer layer 24 of the diaper 21 shown in FIG. 1, the protuberances against the cushion layer were directed. The cushion layers were moistened with the test liquid up to about 5X. After that were the moisture permeability and evaporation tests carried out? the results are in the table below 1 listed.

Example XIII

A test cushion layer was produced which only had the four first layers described above, but no rear layers Layer exhibited. The test cushion layer was grown up to about 5X moisturizes. Thereafter, the moisture permeability and evaporation tests were carried out; the results are listed in Table 1 below.

Examples XIV and XV

Test cushioning layers were produced which were similar to those for Examples IX - XII, with the difference that that instead of the wax-treated tissue product, a silicon dioxide-treated tissue product with a large proportion of voids in the total volume was used. The tissue product treated with the silicon dioxide was creped in the manner described above and coated with silicone in a suspension containing 10% by volume, sublimed silica immersed in "Chlorothene"

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been. This suspension is called Silanox 101 available from Cabot Corporation, Boston, Massachusetts. Thereby per 10 χ 10 cm of the tissue surface were about 0.05 g dry matter added. The test cushion layers were moistened with the test liquid up to about 6X. The results of the moisture permeability test carried out afterwards and evaporation testing are listed in Table 1 below.

Examples XVI and XVII

Test cushioning layers were produced which correspond to those for the Examples IX - XIV were similar "except that instead of the wax treated tissue product, a Non-woven product with a large proportion of voids was used. This non-woven was made of meltblown polypropylene, which had been made into sheet material and from Beloit Corporation, Beloit, Wisconsin, can be obtained. This non-woven became one with a Card cover perforated polyethylene film arranged adjacent. The non-woven product had a contact angle for water from 100 °, one at a measuring pressure of 7.75

2.

pd / cm measured thickness of 0.33 mm, it had a permeability

3 2

air flow rate of 320 dm / min / dm at a pressure difference corresponding to 12.7 mm water column and a basis weight of

2
30 g per m, corresponding to a volume fraction of the voids of 88.9%. The test cushion layers were moistened with the test liquid up to about 6X. The results of the subsequently carried out test of moisture permeability and evaporation are listed in Table 1 below.

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Examples XVIII and XIX

Test cushioning layers were produced which correspond to those of Examples IX-XII were similar, with the difference that the foils provided with conical protuberances were replaced by a Polyethylene film has been replaced by the Allied Synthetics Corporation, St. Louis, Missouri, using the porulation process was perforated. In this process, practically cylindrical pores with a slightly protruding edge are produced. The film had a measured thickness of 46 µm

2 2

Weight corresponding to 64 m / g, a pore number of 309 / m and a pore diameter of 178 yam. The test cushion layers were moistened with the test liquid up to about 6X. The results of the tests carried out afterwards for moisture permeability and evaporation are shown in Table 1 below.

Examples XX and XXI

Test cushioning layers were produced which correspond to those of Examples I - IV were similar, with the difference that the perforated film provided with conical protuberances was replaced by a perforated polyethylene film, as used for the test cushion layers according to the above Examples XVIII and XIX had been used. The test cushion layers were with the test liquid up to about 6X. moisturizes. The results of the tests carried out afterwards the moisture permeability and evaporation are shown in Table 1 below.

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TABLE 1

cn ο co οο ο co ^. ο

example

II

III

IV

VI

VII

VIII

back layer

perforated ribbon-shaped Polyethylene

waxed

Product liquid permeability (g / 15 min)

Test pressure

mZ) 70.4 ^

0.70

1.37

Evaporation rate (g / 1000 cm ² / hour)

6.3

5.1

12.3 12.5

IX X

XI XII )

XIII

waxed product and perforated ribbon-shaped polyethylene

no

0.02

5.6 5.1

16.6

to

CO CO

TABLE 1 (continued)

example

back layer liquid permeability (g / 15 min)

Test pressure
35.2 (PdZCm ² ) 70.4 (pd / cm ² )

Evaporation rate (g / 1000 cm ² / hour)

XVJ

XVI ϊ XVII J

silicon dioxide treated tissue product and perforated polyethylene

Non-woven and perforated polyethylene 0.00

0.03

5.26

3.2

χνΐΙΙΪ, polyethylene with cy-

^ Lindrian Perfora-XIX J tionen and gev / achst Tissue-Produkt 0.07

4.5

XX) XXIJ

Polyethylene with cylindrical perforations 3.37

4.8

ro co

CJ CD

As can be seen from the test results shown in Table 1, both the perforated polyethylene film and Even the tissue product treated with wax is not liquid-impermeable on its own; on the other hand, this is achieved by folding the combined material formed by the perforated polyethylene film and the waxed tissue product practically impermeable to liquids. The table also shows that a combination of a perforated Polyethylene film and a wax-treated tissue product is gas-permeable. This shows that the combination mentioned can be used as a back layer, which is also impermeable to liquids and is gas permeable.

The results of Examples XIV and XVII further show that a layer made of a hydrophobic material with a high proportion of voids used in volume as opposed to the wax treated tissue product in a back layer can be used to form an effective, liquid-impermeable and gas-permeable layer.

It is understandable to any person skilled in the art that other porous, hydrophobic materials with a high proportion of voids can also be used can be used in volume. It is also possible to be hydrophilic Materials by treating with various agents, for example with fatty acids and their salts, vegetable To make waxes, silicones, organofluorine resins and olefin resins hydrophobic and if they have a high percentage of voids in the total volume to be used for the products according to the present invention.

Porous, hydrophilic materials with a relatively large proportion of voids in the volume are, for example, natural and

50 9 809/0885

artificial foams and sponges with open cells, Non-woven products and woven textiles, as well as a wide range of paper products. Such materials can be made directly from foams with open cells and from fiber materials originally made from hydrophobic polymers such as the aforementioned organofluorine and olefin resins.

Although olefin films for the strip-shaped material according to the invention and especially those made of polyethylene are preferred because they are easily available and inexpensive, In addition, many other materials including the polymers of vinyl chloride, polyvinyl chloride, propylene can be used and butylene can be used. The most effective combination in terms of strength and fluid rejection After perforating, it is also possible to use foils made of different plastic materials to form one layer to collapse or to provide with hydrophobic coatings, which are produced with such materials as they have been described for the products with the high proportion of voids in volume.

The following are the most important of the previous ones described measuring method.

The height of the protuberances produced during perforation was measured optically with the aid of a microscope, which is a Fine adjustment screw with a micron graduation. In doing so, the microscope was first placed on the plane of the upper surface of the film on the base line of the protuberance and the corresponding division on the adjusting screw read. Then the adjusting screw was turned until the microscope sharpens the tip of the protuberance.

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was set and read the corresponding division again. The difference between the two readings then gave the height of the Protuberance in microns.

The Elmendorf tear strength was determined according to the Tappi method measured according to US regulation T414M-49.

The ball impact strength became similar to that according to the prescription measured according to ASTM D1709, with the difference that instead of the arrow a steel ball with a diameter of 19.05 mm and a weight of 28.16 g was used. Of the Ring for fastening the foil had a diameter of 76.2 mm. The applied force was changed by adjusting the height of fall of the ball. The height at which 50% the impact caused an open tear in the film was noted.

To measure elasticity, one was used for stress measurements suitable tensile strength testing device, which can also be used for the Testing according to ASTM Standard D-882-67 is useful. This device is called Model TM manufactured by the Instron Company, Canton, Massachusetts. The coupons used had a width of 25.4 now and a length of 50.8 mm. The speed of the crosshead of the Instron device was stretching and retracting 508 mm per minute. The specimens were down 30% or stretched by 55% and then reduced the tensile force back to zero. The permanent one left after the stretch The elongation of the specimen was recorded as a percentage of the original length.

The projected diameter of the perforation was measured by taking a test piece of the perforated tape-like material

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was placed under a microscope which had an eyepiece with calibrated grating.

The permeability of a perforated film to air flow was measured using an airtight chamber on which a sample holder was attached, the one practical

circular opening with an opening area of 10 cm

exhibited. The chamber was via a Fairchild Hiller-Kendall model 10 flow regulator with a metering range from 0 to 0.7 kp / cm overpressure connected to a source of air, and was between the flow regulator and the chamber an air flow meter of the Brooks type, setting 0-150 with a measuring range of 0-6500 cnP per minute installed. Next was a water manometer with one end to the chamber and the other end to the free atmosphere connected to measure the pressure difference between the chamber and the atmosphere.

For this measurement, a test piece with a width of 44.5 mm was cut off from the perforated, band-shaped material and fastened over the opening in the sample holder, with the protuberances facing away from the chamber. Thereafter the air source was switched on, and there was a pressure drop (ΔΡ) readable on the manometer over the test piece set. The flow of air through the flow meter was recorded and used to calculate size: volume of air per time period per effective area of the specimen.

The permeability of tissue products to air flow

3 was in accordance with ASTM D-737-69 in feet / min / foot at a pressure difference of 0.5 inch water column accordingly

3 2 measured 3.05 dm / min / dm or 12.7 mm.

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_0Q_

To calculate the voids in a tissue product was

2 assumed that the weight of the 278.7 m tall unwaxed Tissue product was 5.62 kg and the weight of the same sized waxed tissue product was 6.98 kg fraud. The thickness of the tissue was 0.127 mm at a measuring pressure

2 2

of 12.4 pd / cm. The total volume of the 278.7 m product was then at the specified measuring pressure: area χ thickness = 2.78.10 | ⁶ cm ² χ 1.27. "10 cm. = 3.54.10 cm ²

Of this, the volume of cellulose accounts for:

Cellulose weight _ 5, 62 »10 _ _

Cellulose density (literature value). l.54g / cm ³ '

and the volume of the wax: wax weight

Wax density (literature value)

- (6.98-5.62) .10 ³ g _ _lfl 3 "3 0.8g / cmJ" ¹ ^ ^{7 '10} <= »

The total solid volume is then calculated from the

Cellulose volume plus the wax volume to be 5.35-10 cm

and the percentage of the cavity according to the formula:

(Total volume - solid volume) χ 100 total volume

= (35,4-5,35) .10 ³ cm ³

35.4cmJ ^X

To calculate the cavity in a perforated polyethylene film, it was assumed that the polyethylene film one from the weight of the surface area and the optical measured thickness has calculable density, which is quite good with the density measured by liquid displacement matches. This means that the Polyäthyienfolie at least for the purpose of interest here practically all

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Has properties of a material without voids.

If such a film is perforated with a card cover

2
which has 82 pins / cm with a diameter of 0.228 mm each, with perfect holes being punched out, the proportion of voids caused by the perforations is proportional to the cross-sectional area of the holes.

This results in the following for the cavity created by perforating:

Area of the holes ⁿ "" ⁷ ^ "" * ~ ^{n Λη} ~ ² Surface of the film

_ 82.3Γ / 4- (2.28-10 cm) __., 1 cm ^

Because of its elasticity, the film contracts after perforation, with the diameter of the perforations is decreased. Therefore, the void created by the perforation is actually smaller than the one above Calculation was found, so that a polyethylene film perforated in the manner described above is only a relative has a small amount of hollow space.

As could be shown in the description above, The present invention enables an improved, gas-permeable and liquid-impermeable rear Layer that fully achieves the intentions, goals and advantages outlined at the beginning. Although the invention with the help Preferred exemplary embodiments have been described, it is understood that many alternatives, modifications and changes are possible.

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Claims (3)

PATENT CLAIMS 1. Absorbent device intended for disposal after use is and contains at least one absorbent body and a back layer, characterized in that, that the back layer is impermeable to liquids and (breathable) is gas-permeable! and consists of two adjacent, hydrophobic There are layers, of which the first layer is liquid-permeable and only a small proportion of the cavity Has total volume and the second layer is liquid-permeable and has a high proportion of void space in the total volume and the combination of these two layers creates the passage prevented by liquid, but the passage of vc ^ gases and steaming allowed. 2. Device according to claim 1, characterized in that the first layer consists of a liquid-impermeable film which has perforations through which the layer is liquid-permeable under pressure. 3. Device according to claim 2, characterized in that is the mean projected diameter of the perforations in the Range between about 10 to about 300 jum and the proportion the open area formed by the perforations .. » (breathable) in the first layer in the area that is effective for gas passage / " Ranges from 0.01 to about 5.0 percent of the nominal area of the layer. 4. Device according to claim 2, characterized in that the mean projected diameter of the perforations in the Range between about 10 to about 200 ^ μΐη and the proportion the open area formed by the perforations 509809/0885 in the first layer in the one effective for the passage of gas Range between 0.01 to about 2.0% of the nominal area of the Shift. 5. Device according to claim 2, characterized in that the mean projected diameter of the perforations in the The range is between about 10 to about 100 µm and the proportion of the open area formed by the perforations in the first layer in the effective range for the gas passage between 0.01 to about 1.0% of the nominal area of the Shift. 6. Device according to claim 2, characterized in that the first layer is a permanent extension after being stretched to 30% of at most 15%. 7. Device according to claim 6, characterized in that the mean projected diameter of the perforations is in the range from about 10 to about 100 μm and the proportion of the open area formed by the perforations in the first layer is in the area effective for the gas passage is between 0.01 to about 1.0 percent of the nominal area of the layer. 8. Device according to claim 7, characterized in that the first layer has a plurality of protuberances, and the perforations are arranged in these protuberances. 9. Device according to claim 8, characterized in that the mean height of the protuberances is at least 50 µm, 10. Device according to claim 8, characterized in that the protuberances face the absorbent body. 509809/0885 11. Device according to claim 8, characterized in that the second layer is arranged between the first layer and the absorbent body. 12. Device according to claim 11, characterized in that the protuberances face the absorbent body. 13. Device according to claim 1, characterized in that the first layer has a permanent elongation of no more than 15% after being stretched to 30%. 14. Device according to claim 13, characterized in that the mean projected diameter of the perforations is in the range between about 10 to about 100 _y 0.01 to about 1.0% of the nominal area of the layer. 15. Device according to claim 1, characterized in that the air permeability of the second layer at least 3 2 (1 ° cfm / sq.ft).
'30.5 dm / min / dm with a pressure difference accordingly Is 12.7 mm water column. 16. Device according to claim 1, characterized in that the proportion of the cavity in the total volume in the second layer is at least 60%. 17. Device according to claim 16, characterized in that the second layer is a strip-shaped material composed of fibers is. 18. Device according to claim 17, characterized in that 509809/0 885 a creped tissue product is used as the second layer and the surfaces of the fibers of this tissue product are coated with a hydrophobic material. 19. Device according to claim 16, characterized in that a foam-like product is used as the second layer, which has a plurality of intercommunicating channels. 20. Device according to claim 19, characterized in that the second layer is a flexible, polymeric, foamed material is used with open cells. 21. Device according to claim 1, characterized in that the second layer is arranged between the first * layer and the absorbent body. 22. Absorbent device intended for disposal after use is, containing an absorbent body and a rear layer, characterized in that the rear Layer a gas-permeable and liquid-impermeable Has part and consists of the combination of a first and a second layer, the second layer is arranged between the first layer and the absorbent body and in that the first layer contains: (A) a liquid-impermeable, hydrophobic, polymeric film which, after being stretched by 30%, is permanent Exhibits elongation of 15% or less, (B) a large number of protuberances arranged in the film, the height of which is at least 50 μm, (C) a large number of perforations located in the protuberances, whose mean projected diameter is between 10 and 100 µm and which are practically uniform 509 809/0885 are distributed in the part of the first layer which is provided as an effective gas-permeable part, so that the The proportion of the open area of this part is between about Q.01 and about 1.0%, and in that the second layer contains: one made of fibers, the surfaces of which are hydrophobic Material are coated, formed, band-shaped material which has a cavity portion that is at least 60% of the total volume, and the hydrophobic, fibrous material has air permeability, with a pressure difference corresponding to 12.7 ram water 3 2 column is at least 30.5 dm / min / dm, and that due to the interaction of the two layers what is achieved is that the passage of liquid aurch practically prevents the effective gas-permeable part of the rear layer, on the other hand the passage of Gasea. and steaming is enabled. For: The Procter tf Gamble Company Cincinnati, / Ohio, V.St-.A. Dr * HUJ.Wolff Lawyer 509809/0 885 Blank page