NL8005786A - SANITARY DIAPER. - Google Patents

Description

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Sanitary diaper.

The invention relates to a sanitary diaper and more particularly relates to a diaper with layers of different absorbent materials.

There are several features desirable for a sanitary diaper. The sanitary diaper must be comfortable, it must be highly absorbent, it must quickly remove fluid from the surface adjacent to the user and it must be relatively inexpensive to manufacture.

Butyl pulp fibers or other similar natural cellulose-based fiber systems have long been used as the primary absorbent component of these diapers. Butbut Puff is soft, resilient, absorbent and inexpensive.

One of the difficulties in using hum juice as an absorbent material for menstrual fluid is that there is no preferred direction transfer, so that a higher sweat concentration exists in areas closest to immediate contact. The result is a wet intermediate surface which tends to leak cm quickly. These transfer problems become more serious as the pad 20 gets wetter.

The prior art has recognized these problems and has attempted to provide suitable composite absorbent systems using wood pulp or like materials as one of the absorbent layers. The other absorbent layer, which is usually placed on the top side, is thereby selected on the theory that it is desirable to pass fluid through the surface of the upper absorbent layer as quickly as possible. In some instances this is done by making the top surface 30 of the top absorbent layer "hydrophobic" and / or by selective absorption of the more viscous parts of menstrual fluid in the top layer with, at least theoretically, preventing the aqueous portion of the the menstrual fluid passes through the down layer.

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The theory has also been developed that absorbent systems using two highly absorbent units on successive layers would be very appropriate.

An example of a composite absorbent system 5 known from U.S. Pat. This patent teaches that the top layer 10 described in this way would pass through the less viscous carponents. Suitable fibers to be considered are rayon which has been made relatively hydrophobic on the surface but treated with hydrophilic agents for the inner portion of the fibrous web.

Another representative composite diaper is disclosed in US Pat. No. 4,047,531 and it has an outer dance layer obtained from a thermomechanical gruel used in conjunction with a traditional down layer to an absorbent system. The concept in question is again the use of a "hydrophobic" fiber in the top layer.

There are other known composite absorbent systems, but all have been found to describe the use of an upper layer which is at most less absorbent than the bottom layer and which, in fact, has less actual absorptive capabilities, especially as regards the aqueous components of the menstrual fluid.

The invention provides an absorbent system for a sanitary diaper or the like two-ply article, wherein the layer closest to the user's body allows the fluid to pass quickly through the top surface while still retaining the overall absorbent capabilities, while also the bottom surface of a conventional cellulose-based fiber mat is wetted.

It has been found that the composite absorbent 8005786

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3 systems can be significantly improved by using a top layer which can act as an absorbent for all menstrual fluid components by combining high capacity with good fluid transfer properties.

The menstrual loudness, while in contact with the top absorbent layer of the composite sanitary napkin of the invention, rapidly passes through the top surface of the diaper and spreads. quickly in radial direction 10 as it passes through the thickness of the first layer. During this passage, a portion of all of the components of the fluid are retained.

The topsheet must have relatively large fiber spacing to allow rapid fluid transfer. If a very high fluid retention for the topsheet is present after the topsheet is saturated, there will be fluid runoff between the topsheet and the cellulose-based fiber layer in contact therewith, causing side leakage problems. Also, in the case of a highly absorbent top layer, capillaries in this layer may block due to the high level of absorption which will prevent at least a portion of the straw from contacting the second absorbent layer.

It has now been found that an upper layer having a capillary absorption composition value not greater than 0.5 and an equilibrium capacity not greater than 4.6 grams absorbed per gram of absorbance, in combination with a known layer of cellulose base such as a wood pulp fiber, 3Q provides a highly effective absorption system that utilizes the absorbent capabilities of both layers with a high degree of efficiency without lateral leakage or puckering of the surface at the top of either absorbent layer.

The invention will be explained in more detail below

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4 with reference to the drawing, which shows by way of example an embodiment of a sanitary diaper according to the invention, m shows the drawing:

Fig. 1 is a perspective and partially sectional view of a sanitary diaper construction, and FIGS. 2 and 3 are diagrams of the experiments used to characterize the top absorbent layer in the pad of the invention.

The sanitary diaper N shown in Figure 1 has a fluid permeable outer sheath that completely surrounds the other components of the diaper. An upper absorbent layer 2 is located directly below the bottom surface of the surrounding wrapper. The known wood pulp or like absorbent layer 3 is located directly below the top absorbent layer and is arranged on the top of a fluid impermeable sheet 4. The fluid impermeable sheet actually surrounds the sides of the bottom absorbent layer and may extend for covering parts of the sides of the top absorbent layer. This construction has the advantage of minimizing leakage from the sides of the cushion. The cushion is sealed at the front and rear edges 5 and 6 in a conventional manner, for example by adhesive sealing. The seal is indicated by the near line that lies within the edges of the respective ends. This particular pillow is of the non-card type and, as shown in part with dashed lines, there may be an adhesive peel strip that exposes the lower adhesive surface for attachment to undergarments.

The cushion shown in Figure 1, in its preferred embodiment, utilizes an outer fluid-permeable sheath of spun-bonded polypropylene, as described in U.S. Pat. No. 3,886,942, and a currently preferred sheet material is 0.6 mm. thick polypropylene. The bottom absorbent layer currently (3 Π A s 7 7 ft ψ 5 preferably consists of wood puff down and the top absorbent layer is selected after processing the table below and for cost reasons.

It is noted that the embodiment shown in Fig. 1 should only illustrate a particular configuration which can be selected, and the essence of the invention is not limited to that configuration. For example, a sandwich type diaper can be made in which the fluid permeable topsheet extends only IQ to the edge of the pad and the fluid impermeable base plate is directly attached to the fluid permeable topsheet all around the outer circumference of the pad.

The capillary absorption composition value is obtained by the capillary absorption composition test.

This test is performed as follows: First, the material to be tested is manufactured on a nonwoven fabrication plant set up for comparison purposes to form a nonwoven having a basis weight of 34 grams per square foot. The material is cut to produce a 3 inch diameter 2Q circle. A similar cut of wood puff just three inches in diameter is also cut by the same means and placed under the experimental absorbent material for testing. The test device is shown in Fig. 2.

The test device consists of a syringe pan variable power and means for keeping the temperature and pressure on the object constant. The fluid used for testing is rundef blood whose hemato-critical level, that is, the level of the red blood cells, is set at a level of 20% by weight of the solution. The blood is fed by a pump 11 past a magnetic stirrer 12 through an injector 13 and into the supply tube 14. The supply tube 14 leads to a hollow wall heat exchanger 15 which, as shown in partial cross section, rests on a support block B turn on the 8005786 6 test pads 19 rest. Among the objects is a colostomy bag 10 and it rests on a support 18. The colostomy bag is fluidly connected to a bath 23 of constant temperature via a colostorry supply tube 21 and a ραηρ P. As shown in the drawing, the porridge P provides the heat exchanger 15 ode with a water flow of controlled temperature through a water supply tube 20. A standpipe 22 is also connected to the colostcmy bag by a pressure tube 24. The standpipe together with the bath 23 controls constant temperature, both the temperature and the pressure. The example is held at a constant temperature of 37 ° C, which is the body temperature, by means of the fluid flow of the constant temperature bath at the heat exchanger 15 through the conduit tube 20 (the fluid escaping from the heat exchanger 15 via an exit line 16) and also through the flow-through tube 21 in the eolostemy bag 17. The pressure is kept at 75 cm water column and the flow of the modified bovine blood is maintained at 2 milliliters per hour for 90 min.

The capillary absorption composition value is calculated after 2Q the test is completed. The value is a ratio of the surface area of the spot from the bovine blood of the surface of the absorbent top layer to the spot area on the bottom surface of the bottom absorbent layer, the lower the value the greater the amount of passage in Z- direction of the fluid and spreading the fluid over the bottom surface of the absorbent material. It is noted that the calculated value does not only refer to the capillary properties or the size of the capillaries.

If this were the desired test, it would only take a time measurement to determine how long the fluid takes from one surface to another.

By measuring the actual radial dispersion or dispersion of the fluid along the bottom surface and comparing this value with the dispersion at the top, an indication is obtained for the capillary 8005786 »7 property in connection with the absorption.

The second method used to characterize the top absorbent layer in the pad of the invention is the controlled capacity. By "controlled capacity" is meant that the absorbent layer has some absorbent capacity but of limited value.

As noted previously, it is desirable that the second absorbent layer contribute significantly to the absorption process, and in order to achieve this it is necessary to accurately control the absorbent capacity of the top layer. The value of the absorbent capacity is determined by the capillary absorber shown in Figure 3.

The test will be explained with reference to the component parts of the device described here. This test 15 can essentially be counted as an analysis that determines the ratio between the pore volume and the capillary pressure during absorption of a particular system. The device used by performing this test consists of a filter funnel 35 with a flat bottom PYREX filter-20 disc 40 of medium porosity. The filter disk has a diameter of three inches and the sample obtained was described in the previous test and cut to a three inch diameter configuration and placed on the filter disk. A tube 33 connects the funnel to a length of capillary glass tube that is in a fixed horizontal position. The fluid reservoir 30 is connected to the capillary tube 31 by a three-way valve 32. A drain 36 is placed between the capillary tube and the valve. The capillary tube is either calibrated internally or by using a 30 meter tok so that the volume of fluid per centimeter of the tube can be calculated. The reservoir 30 is filled with a commercially available research fluid called Isoton.

This fluid has a pH of 7.4 and the surface tension was adjusted to 54 dynes. After filling the reservoir 35, a continuous column of liquid extends from the bottom surface of the filter plate to the capillary tube.

A porous Teflon weight of about 210 grams is placed on the top of the sample while resting on the sample plate and a lid is placed over the filter funnel to prevent fluid loss. The filter funnel 35 is mounted on a graduated gauge rod 34 and the funnel is raised to a position of 60 centimeters with the drain valve closed. The valve is then opened to allow free flow of fluid from the sample being tested to the capillary tube. The system is then allowed to core in equilibrium with an equilibrium depending on the particular choice of the absorbent pad tested. The cell is then moved downward at predetermined intervals, each of which allows for equilibrium until the entire volume of the sample is filled, ie, 0 centimeters.

At this point, the sample has passed from the dryness state to one of full saturation. In view of the particular test, the absorbent value selected is the amount of fluid retained per gram of absorbent material at 30 centimeters height on the desorption cycle.

A range of absorbent materials were tested with this procedure and the results are shown in the table below.

Table I

Material description

Capacity

Capillary

Base weight Spot stain tension 25 Material g / ft. above / ender (g / 9030 cm)

Wadding 34 g / ft2 1.07 1.54 (20 strokes)

Wood puddles 32 g / ft2 0.77 4.6

Polyester 3.0 32 g / ft2 0.06 0.6 30 Denier

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* 9 ABS0RBI3? 3/3 33 7g / ft 0.13 1.54

Denier ABSORBIT 1.5 33 g / ft2 0.78 3.0

Denier 2 5 Rayon 1.5 Denier 32 g / ft 1.14 1.4

Rayon 3.0 Denier 32 g / ft2 0.28 1.5 2

Polyester / Rayon 32 g / ft 0.05 0.4 80/20 Blend 3.0 Denier 10 BUCKEYE CLD 34 g / ft2 0.12 7.58 UIIAIjCN 34 g / ft2 0.10 7.79 2

Thenno-Mechanical 34 g / ft 1.39 3.40 (Australian IMP) (Pinus Radiata) 15 The porridge termed thermo-mechanical in the table is an example of the material of U.S. Pat. No. 4,047,531.

AQDALON is a trade name of Hercules Incorporated and is a material known for its high absorbent or super absorbent properties. The composition is based on cotton fluff treated with carboxymethyl.

UCKEYE CLD is a trade name of a Procter & Gamble and is also a so-called super absorbent material and consists of carboxymethyl treated wood pulp fibers.

25 ABSORBIT is a trade name of American Enka,

Division of Akzona and is an alloyed cellulose fiber containing an alkali metal salt or ammonium salt of a copolymer or terpolymer of acrylic acid and / or methacrylic acid.

It should be noted that the denier appears to have an important effect on the ability of the particular materials selected. The higher denier absorbent and the higher denier rayon samples meet the criteria for the test, but the lower denier absorbite and the rayon samples do not. It is therefore clear that in order to meet the particular test parameters that limit the present invention / factors other than the choice of the absorbent material play a role.

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Claims (4)

1. Flexible and soft sanitary diaper, characterized in that it consists of: already a fluid permeable top layer, a first absorbent layer of a relatively thin, highly absorbent material with large capillaries, which absorbent material has a capillary absorption composition. has a value not greater than 0.5 and has a capacity not greater than 4.6 grams absorbed / gram, cl a second layer of conventional cellulose-based absorbent material placed under the first layer, and dl a fluid impermeable plate. 2. Bandage according to claim 1, characterized in that the top layer constitutes between 5 and 80% by weight of the total absorbent material. Bandage according to claim 1, characterized in that the top layer constitutes from 15 to 60% by weight of the total absorbent material. 4. Panty liner or similar diaper as shown 2Q in the drawing and / or discussed accordingly. 80057 = ¾