DE2358394C2 - Disposable diaper - Google Patents

Description

The present invention relates to a disposable diaper, which consists of a liquid-impermeable back layer, a liquid-absorbent pad and from an overlying hydrophobic cover layer made of an Ethylenäthylacrylat film, which with a A plurality of rectilinear slots is provided

A disposable diaper of this type is known from DE-OS 21 46 278. In this diaper, the upper layer of which is made of a hydrophobic material which is provided with slits, the liquid can therefore only gelatijen through the slits to the actual absorbent material. These slots have a kind of valve action, ie they can be opened to allow liquid to pass under certain conditions and closed to prevent the passage of liquid under certain other conditions. In the open state, the closable openings should have the capability of at least 20 ml of liquid to pass ^{through a wetted area of approximately 130 cm 2 within 10 seconds.}

However, the time required for soaking, that is to say the time until the absorption of the liquid actually occurs in the absorbent material, is still insufficient. The retention of urine before vacuuming starts so is so great that discomfort may occur.

Another known embodiment of a disposable diaper is described in DE-OS 17 10 985. here the absorbent layer is provided with depressions on at least one side. This absorbent with The layer provided with depressions is at least on this one side with a liquid-permeable soft, cotton-like layer, mostly rayon wool, in which the liquid only spreads insignificantly can. This causes the liquid to penetrate through this soft layer and then into the one next to it Depressions added, thereby their spread in the absorbent layer, which by this Wells have received a larger surface, should be facilitated. Since the outer layer is the Liquid cannot spread or spread only insignificantly, arises on the skin facing the child Side of the diaper 50 for a long time a damp feeling, until the urine or other secreted liquid through the liquid-permeable layer has passed through and over the depressions of the actually absorbent layer is added. If larger amounts of liquid are present, the The liquid in the soft material does not spread or spreads only insignificantly and accumulates on the skin, at least for a shorter period of time, the build-up of liquid results in an uncomfortable damp feeling

It is therefore the object of the present invention to provide a disposable diaper with improved absorbency.

This object is achieved by the features characterized in claim 1

Surprisingly, it has been shown that the effectiveness of the diaper by the invention Training has a largely improved absorption capacity because it initially increases Liquid can accumulate in the wells caused by the introduction of the wells into the Foil that has already been slotted further open contactors can be passed on at higher speed into the liquid-absorbent insert. Another advantage consists in the fact that when the depressions are made, the insert which absorbs the liquid underneath is compressed; these parts are connected to the more open slots, whereby a Soaking up the liquid is achieved to a greater extent. In fact, most of the Cases currently. To the extent that the liquid transfers to the absorbent pad the pad will absorb the liquid over its entire area until either partial or complete saturation is reached, if this is the case the compressed material expands and pushes the indentation upwards, closer to the plane of the Top layer. This action is used to close the previously open slots, causing the liquid in the absorbent pad inserted, 'jigen will. It will therefore according to the present invention a maximum wicking and absorption effect in the course of the critical period of time during fluid flow (e.g. when urinating and similar processes) achieved during the passage of the liquid from the absorbent pad back through the same Slot openings is considerably reduced because of the combination of the blocking effect by the Slots and those in the indentations.

The depressions can be arranged in a variety of patterns on the absorbent article. That is, the effect of the entire pattern can be a diamond, curved line, herringbone, and other patterns. The preferred pattern consists of a system of substantially straight, staggered, parallel rows along the surface of the topsheet. The number of depressions per 6.5 cm ^{2 of} the area of the absorbent pad can be varied over a relatively wide range. Even when only one well (1.27 mm diameter) per 6.5 cm ^{2 of} absorbent pad was used, improvements were observed. Further, it was observed that good results were obtained even when 100 depressions (1.27 mm in diameter) were used in 6.5 cm ^{2 of} the area of the absorbent pad. Of course, this must be taken into account.

that the number of wells that can be accommodated in an area of 6.5 cm ^{2 of} the insert depends on the size of the wells. As a general rule, the total area occupied by the indentations should not exceed 20% of the surface area of the insert. Excellent results are obtained when the total area of the wells occupies 4 to 12% of the surface area of the absorbent pad. Approximately 3 to 25 wells (2 ^ 54 mm in diameter) are placed in 6.5 cm 'of the surface area of the pad . Preferably about 6 to 15 depressions are provided on 63 cm ^{2 of} the surface area of the insert.

As a general rule, the diameters of the dimples can range from about 0.635 to 635 mm lie. From the standpoint of functionality and aesthetic quality, it is preferred that the depth of the depressions is in the range of about 1.905 to about 3.810 mm for the diameter. The depressions also serve the purpose of improving dimensional stability and an aesthetic one To convey an impression of the material.

The disposable diaper according to the invention is assembled in the usual manner before the Upper layer is slit. A rotating slitting device can be used for this purpose without a Damage to the rear film or a loss of impermeability to the liquid occurs

The depressions can be formed in the cover layer in a variety of ways. The easiest The procedure is carried out with a roller, which is equipped with heating means, and a variety of Has spikes or specials, which protrude beyond the width of the roller and its circumference. The spikes, Spikes or probes, which have smooth, rounded endpoints, can be used on the Roll be arranged to the desired number of depressions on the absorbent article deliver. The indentations are formed after the slots have been formed but before they are fully fabricated the diaper.

The invention is explained in detail with reference to the drawings; shows here

F i g. 1 is a plan view, partly in section, of a disposable diaper according to the present invention;

2 shows a section along line 3-3 Fig. 1;

3 shows an enlarged section from the Cross-section according to FIG. Fig. 2 showing a portion of the thus disposable diaper in an unsaturated state;

F i g. 4 is a view similar to that of FIG. 3, with the exception that the disposable diaper with liquid is saturated.

Fig. 1 shows a disposable diaper 10 including the rectangular absorbent pad 12, the flexible backsheet 14 of liquid impervious material, and the flexible topsheet 16 which is normally also made of liquid impervious material. A system of slots, which are designated by the reference numeral 18, and a system of indented areas 22 (depressions) are distributed over the surface of the cover layer 16. The slots 18 are arranged in longitudinal rows such that each <> 5 row represents an elongated region of substantially parallel, straight slots, each of which is angularly oriented with respect to the longitudinal axis of the row. Adjacent rows are similarly arranged but with the deviation that the slots are arranged in such a way that the end points of each slot lie on a line which runs substantially between the end points of corresponding slots of adjacent alternating rows. The slots suitable for the present invention must be substantially straight because if they have a curved, V-shaped, or other configuration, then they form tabs in the surface of the film which can flex open, negating their effectiveness. Each of the slots should be about 0.762 to about 635 mm in length. Preferably, ^{about 30 to about 150 slits are provided every 6.5 cm 2} , each of these slits being about 1.778 to about 5.08 mm in length. Most preferred films contain about 81 slits ^{per 6.5 cm 2, of which} each approximately 2.54 mm in length

The indented areas 22 (depressions) are in the manner shown in FIGS. 1 to 4 over the Surface of the topsheet distributed. That is, it can be seen that the topsheet 16 has a plurality of Depressions have soft in staggered, parallel rows along the surface of the topsheet (Fig. 1) are arranged, and which extend below the level of the upper class (Figs. 2 and 3). It is important that the Depressions are formed in such a way that there is essentially no breakage or cutting of the Upper class occurs in the course of manufacture or afterwards

For these reasons and also to facilitate and simplify the production are circular depressions as shown in FIGS. 1 to 3 shown preferred

From FIGS. 2 and 3 it can be seen that the depressions 22 are a short distance below the plane of the Topsheet 16 and that the absorbent material 12a immediately below the depressions in compressed state is present. At the points where the depression over a section of the Slot 18 has been formed, it can be seen that the slot is open to a far greater extent than corresponding ones Slots that are apart from the depressions 22. However, because of the arrangement of the depressions, the Slots, which are arranged between corresponding depressions, more open than would be the case, if there were no indentations. This is due to the fact that the pressure, which is exerted from the depressions on the surface of the topsheet, under the influence of a Tensioning the top layer causes the slits to open slightly. Parts of the compressed, absorbent Pad are connected to these open slots, and because of this contact v / ird a high level of absorption is achieved.

An assay method is described in the following examples. Following the procedure used in the following examples, an open cylinder with an inner diameter of 101.6 mm is placed on a portion of the absorbent article. In the cylinder, 30 ml of a liquid, such as water or a salt solution is poured and the time registered soft ium absorbing this 30 ml of liquid (which at a temperature of 35 to 38 ° C is maintained) required by the hydrophobic film through

is borrowed.

example 1

An absorbent pad made of eight layers with the approximate dimensions 305 × 406 × 4.76 mm was used placed in the middle on a foil made of polyethylene film with the approximate dimensions 311 ■ 412 ■ 0.032 mm, in which a taffeta-like pattern was embossed.

A 0.032 mm thick sheet of ethylene-ethyl acrylate film was perforated or slit by yielding through the gap between a roller with a plurality of small blades, which were arranged in staggered parallel rows around the circumference of the roller, and one rear roller was guided. The perforating roller had ^{approximately 125 blades on 6.5 cm 2} , so the perforated film also had approximately 125 parallel slots per 63 cm ^{2 of} surface area, each slot being approximately 2.54 mm in length.

Dpr gp <trhlii7ie film was cut into pieces with the approximate dimensions 311 x 412 mm and placed this on top of the absorbent pad, making the last one sandwiched between the slit film and the polyethylene film was wrapped. The edges of the wrapping material wjrden then welded under the action of heat.

The absorbent article was then placed under the cylinder and the wicking properties examined. To this end, 30 ml of a liquid, i. H. an 03 n sodium chloride solution at body temperature (to simulate urine) poured into the cylinder. Within 74 seconds the Liquid is completely absorbed by the absorbent material through the cover layer.

The cover sheet was then carefully removed and placed on top of another, identical absorbent material, and the edges were then resealed. The absorbent article was then passed, with touching contact, past a roller which was equipped with heating devices and with approximately 10 pins per 6.5 cm ² which protruded over the width of the roller and beyond its circumference. The diameter of the pins was 2.78 mm and the end point of the pins was designed spherically with a radius of curvature of approximately 1,389 mm. The absorbent article was held by a resilient rear roller. Means a system which circulated in the hot oil having a temperature of 177 ⁼ C, the pins were held at a temperature of about 150 C ^c. The absorbent product obtained had approximately 10 depressions per 6.5 cm ² along the topsheet of the absorbent article. The absorbent article was then subjected to the same initial wicking and wicking test discussed above. It was found that within 14 seconds the liquid was completely absorbed through the cover layer in the absorbent insert

Example 2

This example shows that without closable openings no or almost no liquid can pass through the depressions in the top layer passes through

An absorbent article was made substantially similar to the article of Example 1 corresponded, but with the difference that the formation of the slit did not take place. That is, the absorbent The object corresponded identically to the object according to Example I, but with the difference that dip Cover layer had no closable openings (slots). According to the procedure according to the example! > The water absorption of the absorbent article was examined. After a period of No apparent absorption of the liquid in the absorbent material was observed for 3 minutes. The liquid remained as a whole on the surface of the top layer. That means essentially kicked no liquid through the indentations of the topsheet.

Example 3

π An absorbent pad made of eight layers of absorbent wadding with the approximate dimensions of 305 × 406 × 4.76 mm was placed in the middle on a sheet of polyethylene film with the approximate dimensions of 311-412-0.032 mm, with a 2 " taffeta pattern embossed in the latter .

A 0.032 mm thick film of ethylene-ethyl acrylate-FiIm was characterized slotted so reciprocated in contact with one and reciprocating rod was placed, which had a plurality of small cutting edges 2>, which reciprocates over the surface of reciprocating Rod were distributed. The perforated film thus produced had ^{approximately 72 parallel slits per 6.5 cm 2} , each of which was approximately 2.03 mm in length.

JO The perforated film was then cut into pieces with dimensions of 311 × 412 mm and placed on top of the absorbent wadding pad, sandwiching this pad from the perforated film and the polyethylene film was wrapped. The edges of the wrapping material were made then welded under the action of heat.

The absorbent article was then placed under the cylinder (inner diameter 101.6 mm) and investigated the properties upon absorption of 30 ml of liquid (simulated urine). Within Within 57 seconds the liquid was completely through the topsheet and into the absorbent Absorbent pad.

The topsheet was then carefully removed and replaced with a different, identical absorbent Material laid, and the edges welded again.

The absorbent article was then passed, with touching contact, past a roller which was equipped with a heating device and with approximately 10 pins per 6.5 cm ² , the pins protruding over the width of the roller and beyond its circumference. The diameter of the pins was 2.78 mm and the end point of the pins was spherical with a radius of curvature of approximately 1389 mm. The absorbent article was held or supported by a flexible, rear roller. By means of hot oil (177 ° C.) circulating in a corresponding system, the sticks were heated to a temperature of approximately 150 ° C. w> The absorbent obtained in this way Product had approximately 10 depressions per 64 cm ² along the topsheet of the absorbent article. The absorption property of the absorbent article was then examined in accordance with the above procedure, and it was found that the liquid was completely absorbed through the topsheet and into the absorbent material within 4 seconds.

1 sheet of drawings

Claims (3)

Claims; U disposable winch), consisting of a liquid-impermeable back layer, a liquid-absorbent insert and an overlay s arranged hydrophobic cover layer made of an Ethylenäthylacrylat film, which with a variety rectilinear slots are provided, characterized in that the cover layer (16) is also formed with a number of recesses (22) directed towards the insert (12) and having a circular cross-section, in the walls thereof there are also slots (18). 2. Disposable diaper according to claim 1, characterized in that the total area that the Take up depressions (22) over the surface of the insert (12), 4–12% 3. Disposable diaper according to claim 1 or 2, characterized in that there are ^{6-15 recesses (22) on 6.5 cm 2 of} the insert (12).