CZ20003276A3 - Moisture distributing substances with enhanced properties of distribution at lower extent of moistening - Google Patents

Abstract

The present invention is a fluid handling member having improved balance of permeability, ability to release fluid both at full and partial saturation. This member has (i) a sufficiently open structure with a permeability of at least about 1 Darcy at 100 % saturation, (ii) the ability readily release the fluid contained therein by having a low Capillary Sorption Desorption Height (CSDH 50) of less than about 150 cm, and (iii) a permeability at 50 % of their saturation, which is more than about 14 % of the permeability at 100 % saturation. A preferred execution of such materials comprises an open celled foam material, such as of a High Internal Phase Emulsion (HIPE) type. Such materials are particularly useful for absorbent articles, such as diapers, adult incontinence articles, or feminine hygiene articles.

Description

Moisture distributing agents with improved distribution properties at a lower humidification rate

Technical field

The present invention relates to moisture distribution elements which are characterized by improved moisture distribution properties and which can be used in particular in sanitary absorbent articles such as diapers, parts of sportswear, anti-fouling agents for adults and female sanitary articles. absorption of body excreted substances such as urine, menstrual discharge, sweat or loose stools.

BACKGROUND OF THE INVENTION

Substances having specific moisture distribution properties are well known in the art of absorbent and disposable materials. The need for these substances has increased considerably with the introduction of highly absorbent (i.e., absorbent gelling masses) or superabsorbents, which can sufficiently absorb body fluids (e.g., urine) but do not allow increased moisture distribution. The use of absorbent compositions of less advantageous shape or less preferred materials may even reduce the moisture distribution (this phenomenon is often referred to as "gel blocking"). For example, in substances in which the superabsorbent mass is a homogeneous mixture with pulp fibers, a certain critical concentration (which is firmly determined by the selection of the superabsorbent mass) should not be exceeded in order not to impair the functionality of the absorbent core.

As a result, a number of different forms of absorbent cores have been developed with different functions of the lots. These absorbent cores, in addition to their moisture-absorbing components and / or substances, also contain parts which have specific properties for increased absorption or for more efficient distribution of the moisture retained. Often the same portion of the absorbent composition serves to increase both absorption and distribution of moisture simultaneously.

Initially, the demands on the moisture distribution properties of the substance were not too high.

Conventional paper pulp (e.g., US-A-3.952.745) has also been used to produce absorbent cores, which has also been used to increase moisture distribution (EP-0.343.941, US-A-4.578.068).

Further developments can be illustrated in the following documents: EP-A-0.397.110 discloses an absorbent article having a variable functionality portion to improve moisture distribution that has been characterized by precise basis weights, absolation intervals, and residual moisture; US-A-4,898,642 discloses some curved and chemically stiffened cellulosic fibers and absorbents with these fibers; EP-A-0.640.330 describes the use of this type of fiber in combination with certain superabsorbent materials.

Other attempts have been made to improve the suction properties of the pulp fiber based fabrics: US-A-3.575.174 or US-A-4.781.710, where portions of the surface are compressed to a higher density, thereby creating smaller pores with a higher suction height, e.g. in the form of lines or patterns.

Since some of these substances were unpleasant to the touch, post-treatment procedures have been developed to achieve the desired softness. This post-treatment consists in that, instead of (or in addition to) softening the material during its manufacture or fabric formation, the fabric, after pressing and drying, is processed mechanically in a separate manufacturing step, often before further processing, such as absorbent core and / or composition (US-A-5,117,540, US-A-4,440,597).

• ·

Further experiments have focused on the pore size of the moisture-distributing materials: US-A-5.244.482 discloses reducing the maximum pore size by turning the meltable fiber in one direction with subsequent thermal stiffening of the deformed fibers.

In addition, special combination materials have been developed with regard to pore size and the distribution of different porous structures. These improvements are described in more detail in US-A5.549.589 or in WO 97/38654, and essentially consist of providing a flexible structure in which particularly stiffened pulp fibers (e.g., crossed softwood pulp fibers) with large pores filled small and narrow pulp (eg eucalyptus) fibers. Both processes also include steps to achieve sufficient cohesion and strength of the fabric, in the first case by adding thermoplastic fibers and partially melting them, in the second case by adding a chemical binder.

Further attempts (patent application EP-A-0.810.078) have focused on special additional mechanical processing of the netting in order to achieve better suction and moisture distribution properties (eg the above-mentioned higher average flow rate at certain suction heights).

In order to increase the functionality of the absorbent articles according to the increasing demands, more detailed research has been carried out on porous materials. Synthetic fibers with a higher surface area (US Statuary Invention Registration H1511) have been used in absorbent materials to provide better longitudinal moisture distribution. Other materials took the form of foams, such as cellulose foams (Spontex SA., France).

Other polymeric foams for absorbent compositions are disclosed in US-A-5,268,224, namely, high internal phase polymerized masses that can be used to trap fluid while simultaneously distributing the trapped fluid to prevent local supersaturation.

However, all these developments have until recently been concerned with the improvement of suction-related moisture distribution properties of substances, such as flow rate, suction height and suction intervals. The importance of the mechanism of distribution of moisture scavenging agents has been neglected, especially in the case of incomplete saturation.

Objectives of the invention

It is therefore an object of the present invention to provide substances that readily release fluid, especially at low saturation.

Another object of the present invention is to provide substances capable of more readily distributing moisture even at low or moderate saturation rates.

It is a further object of the present invention to provide absorbent compositions employing said materials which will thus exhibit improved moisture distribution properties.

SUMMARY OF THE INVENTION

The present invention relates to moisture trapped distribution elements which are characterized by a more balanced permeability and fluid release capability at full and partial saturation.

These substances have a sufficiently open structure with a 100% saturation throughput to (100) of more than about 1 Darcy, preferably more than about 2 Darcy, more preferably more than about 8 Darcy, and even more preferably more than about 100 Darcy.

• ·

Furthermore, these substances are capable of readily releasing the entrapped fluid, as they have a capillary sorption desorption height at 50% of their capacity at 0 cm (DVKS 50) of less than about 150 cm, preferably less than about 100 cm, more preferably less than about 75 cm and even better, less than 50 cm.

Further, they are characterized by a permeability at 50% saturation k (50) which represents more than about 14% permeability at 100% saturation k (100), preferably more than about 18% permeability at 100% saturation, more preferably more than about 25 % permeability at 100% saturation, and even more preferably more than about 35% permeability at 100% saturation.

A preferred embodiment of these materials comprises open cell foam, such as High Intemal Phase Emulsion (HIPE).

These substances are particularly suitable for use in absorbent articles such as diapers, adult anti-fouling compositions and feminine hygiene articles.

Brief overview of the drawings

Figures 1-4 illustrate different procedures for performing permeability tests. Drawings 1 and 2 relate to the simplified test, drawings 3 and 4 relate to the general test. Figures 1 and 3 relate to the measurement of transplanted transmittance, and Figures 2 and 4 to the measurement of surface permeability.

Figure 5 shows schematically an apparatus for performing a capillary sorption test.

Figure 6 shows a diaper as an example of an absorbent article.

Figure 7 shows schematically an apparatus for performing a vertical suction flow test.

DETAILED DESCRIPTION OF THE INVENTION

The term "moisture distribution element" in this context refers to the functional parts of the absorbent article in terms of moisture distribution. The absorbent article may comprise one or more different moisture distribution elements, e.g., one or more moisture extraction beer, one or more moisture distribution elements, or one or more moisture acquisition elements. Each of these elements may further comprise one or more sub-elements which may (but need not) be in the form of a homogeneous substance, i. each element may be made from one or more substances. These elements may, for example, be in the form of layers, which optionally consist of layers of sub-structures of optionally different construction, density or thickness.

Each of these elements can fulfill a certain function, such as a function of suction or a function of trapping moisture. The elements may alternatively perform several functions at the same time, similar to the developmentally oldest pulp of mere pulp, where the pulp mass simultaneously provided the functions of suction, distribution and moisture collection.

The term "absorbent element for absorbing moisture" refers to the absorbent core element, the function of which is primarily to ultimately absorb absorbed moisture.

By "moisture distribution beer" is meant within the scope of the present invention an element which fulfills the requirements set for the moisture distribution function, regardless of whether it fulfills any other fluid handling function.

The term " moisture evacuation element " refers to absorbent core components that are primarily intended to receive moisture supplied to the absorbent article.

The term "absorbent core" in this context refers to those elements of the absorbent article which are primarily used to distribute moisture, including including "moisture distribution element (s)". Usually, the face or backside of the absorbent article is not considered to be part of the absorbent core, although in some cases, for example, the face surface may perform the function of evacuating moisture.

The absorbent core may be subdivided into "functional portions", which may perform the function of one or more of said elements. The functional part of the suction can thus consist of the suction element (including other elements) and can also consist only of the suction element itself (and no other elements) containing the suction substance. E.g. the functional part of the suction / moisture distribution may thus comprise both a suction element and a fluid distribution element.

In this context, the term " aseptic means " refers to means for absorbing and retaining body exudates, more specifically, means for proximity to or on the body of a user that serves to absorb and retain the various exudates excreted by the body. Urine, menstrual discharge, sweat and faeces (but not only these) are referred to as 'body excretions'.

The term "disposable" refers to those absorbent articles which are not intended to be cleaned and reused (i.e., to be disposed of, preferably for recycling, composting or other treatment in an environmentally sound manner).

"Dimension Z" here is an orthogonal dimension to the length and width of the element, core, and device. The dimension Z usually corresponds to the thickness of the element, core or device. "X-Y dimension" refers here to a plane orthogonal to the thickness of the element, core, or device. The X-Y dimension usually corresponds to the length and width (respectively) of the element, core, or device.

The terms "parts" or "lots" in this context refer to parts or parts of an absorbent element. The parts or lots may thus be two-dimensional (front / rear) or three-dimensional (such as a suction portion that is three-dimensional, although in the form of a layer).

The term "layer" in this context refers to an absorbent element, given in particular by the dimensions X-Y, i. length and width. It must be understood that the term layer need not necessarily be limited to individual layers or areas. Thus, the layer itself may consist of several layers of another or of several surfaces or meshes of similar types of substances. Thus, the term 'layer' includes the terms 'layers' and 'layered'.

For the purposes of the present invention, the term "top" should refer to absorbent elements, such as layers, which are located closest to the skin of the user of the absorbent article, and which are typically located near the Kenya area. Similarly, the term " bottom " refers to absorbent elements which are furthest from the user ' s skin and which are generally located near the back surface.

All ratios, proportions and conversions used herein are by weight unless otherwise stated.

Improved moisture distribution element

The requirements imposed on moisture distribution elements can be assessed in two respects, either in terms of the element itself or in terms of the substances used. In this »· · I

Accordingly, the requirements set forth in the specification must be satisfactorily addressed either in terms of the element as a whole or in terms of the substances used.

The moisture distribution beer and / or the substance of this element according to our invention can therefore be described according to the following important parameter:

1) Permeability of the element or the substances used in it at full saturation k (100). Conventional moisture-permeable substances are characterized by a permeability leveled to achieve an optimum state between a low resistance to fluid flow (i.e., a high permeability) and a sufficient capillary pressure, with a resultant absorbency caused by small pores (i.e., a low permeability). The permeability at full saturation (klOO) should generally be greater than 1 Darcy (with 1 Darcy corresponding to 9,869.10 ^B m ² ), preferably more than 2 Darcy, or even 8 Darcy, or even more preferably more than 100 Darcy. Full saturation can be determined by the capillary soap test described below as the maximum amount of fluid delivered, which corresponds to a resulting capillary sorption absorption capacity of 0 cm (AKKS 0).

2) Dependence of permeability on saturation rate. This feature has not been taken into account in previous documents. Conventional substances are considerably below average in this respect; the throughput at a saturation rate of less than 100% is considerably lower than would be the linear correlation between true throughput and saturation.

3) Capillary sorption pressure, mainly desorption capillary sorption pressure, as a result of the capillary sorption test described below. This refers to the ability of substances or elements used to release fluids.

In addition, and often preferably, the moisture distributing materials may meet the criteria of the high fluid flow rate described below in the vertical absorbency test. These materials allow the absorbency at a height of 15 cm, preferably at least 0,045 flow g'cm ^{2 /} sec, preferably more than 0.06 g / cm ² / sec, more preferably more than 0.10 g / cm ² / sec.

By carefully selecting the substances meeting the proper balance of these parameters, considerably advantageous properties of the absorbent substances and / or the elements containing them can be achieved.

1) Moisture-distributing substances can be quickly cleared of moisture after receiving a dose of urine. This is important because the substances are readily capable of absorbing additional moisture, as is the case in normal use.

2) These substances allow a more even distribution of the entrapped fluids, even at doses relatively small relative to the capacity of the composition. This is particularly important in the case of devices which aim to maintain a better fit on the user's body by preventing the accumulation of moisture in some parts of the device and which therefore aim to evenly distribute the entrapped fluids.

3) If these substances meet the high flow criteria, the moisture distribution is good and fast, even in the direction against gravity. This is particularly important if a space remote from the suction areas is provided for the final fluid acquisition. Such materials are particularly desirable in embodiments of the absorbent core of PCT application US 97/05046 of Mar 27, 1997.

The permeability rate of said substances or elements can be determined using the permeability tests described below.

Without wishing to be overly theoretical, we believe that the true permeability to {S} is given by the degree of saturation and that it can be derived from the following equation for many relevant systems:

to {S} = to {100} * {With ^SDP } • ·

-6k - throughput in Darcv

SDP - dimensionless exponent or saturation dependency parameter (for atypical behavior)

S - a degree of saturation from 0 to 1, with a value of 1 indicating full saturation, i. (100% saturation) at zero external and / or capillary pressure

Measures for carrying out moisture distributing agents have focused on achieving high saturation permeability values of k (100). This, of course, could have led to the development of substances with low or no absorbency, which would thus be suitable as moisture-absorbing substances (where the "free flow regime" would have to be modified) but would not be suitable for moisture distribution. Such substances would have a very poor moisture distribution, for example a distribution in the direction opposite to gravity. Conventional moisture extractors are characterized by such special properties, although the moisture distribution substance described in patent application EP-A-0.809.991 discloses a combination of absorbency and free flow control - but still under full saturation conditions.

The compounds of the invention have a permeability to (100) of at least 1 Darcy, preferably at least 2 Darcy. Higher permeability values result in even less resistance to fluid distribution and are preferred, if possible, without compromising the other requirements herein. In particular, substances with a permeability greater than 8 Darcy or even greater than 100 Darcy may be very suitable.

It is apparent from the above equation that higher SDP values describe systems with more atypical behavior (if the SDP value is equal to 1, the relationship would be linear). The available moisture-distributing substances are characterized by markedly atypical behavior (they can be expressed as SDP values of 3 or more). At such a value, the transmittance at 50% saturation represents only 12.5% transmittance at 100% saturation, thereby also dramatically reducing the ability to receive and distribute the next fluid dose.

Thus, the SDP value of the compounds of the invention is less than 3, preferably less than 2.75, more preferably less than 2.5, even more preferably less than 2. At such values, the permeability at 50% saturation is more than 14% at 100% saturation, preferably greater than about 18%, even more preferably greater than about 25% and even more preferably greater than 35%. At such values, the transmittance at 30% saturation is more than about 3.5% transmittance at 100% saturation, preferably more than about 5% and more preferably more than about 10%.

By means of a simplified permeability test, as described below, the "transplanar" permeability (i.e., permeability to a selected sample depth) can be measured, and the area permeability can also be measured using a simplified cell sample. For many substances (eg isotropic foam), the transplanar and transmittance values will necessarily be identical. With this simplified permeability test, it is possible to measure permeability under two special conditions: it is possible to measure either the permeability for the whole range of porous masses (non-woven synthetic fiber or pulp mass) at 100% saturation, or the permeability of substances at different saturation degrees with by proportional change in thickness (not filled with air), whose permeability at different degrees of saturation can be measured at different thicknesses.

Said flexible foams are, for example, characterized by a thickness which depends on the degree of saturation, i.e. the thickness of the foams. at a certain saturation, they have a thickness that decreases as the fluid decreases - the polarity of these substances is such that they decrease in fluid loss. The reverse process is possible using a certain »· · · · · · · ···

-Ί average to define a certain degree of saturation. In the case of these substances, the permeability to saturation can be readily determined by this simplified permeability test.

With the general permeability test described below, the permeability dependence on the saturation of porous substances in a general sense can be measured (i.e., in the case of porous substances, netting, or foams with pore size substantially unaffected by the degree of wetting).

Another important requirement for the substances and / or elements of the present invention is their ability to further release the fluid into the moisture retention medium. This illustrates the fact that the substances or elements of the moisture distribution should not retain the fluid for too long, but only for the time necessary to transfer the fluid into a suitable substance or fluid acquisition element.

A suitable parameter to determine this capability is the desorption pressure of the capillary sorption, which is given by the ability of the substance or element to absorb and release fluid at various capillary pressures (in units of column height of water - capillary height). The Capillary Sorption Absorption Capacity Test (also referred to herein as the Capsorption Test) measures the amount of test fluid per gram of absorbent element or substance absorbed or released upon placement of the element or substance at various heights in the capillary sorption device. The capillary sorption absorption capacity test is described in more detail in the Tests section and indicates the height at which the test substance releases 50% of the absorbed liquid at the ocm sorption height (capillary desorption height - DVKS 50).

Substances useful in the context of the present invention should have a DVKS value of less than 150 cm, preferably less than 100 cm, more preferably less than 75 cm, and even more preferably less than 50 cm.

For the purposes of the present invention, hydrophilic, flexible, open cell interconnected polymeric foams are particularly suitable.

The mechanical strength of these foams may be such that the release of fluid reduces the volume of the foam due to capillary pressures. By reducing the volume of the foam, the effective capacity of the foam is reduced according to a real factor related to the density of the foam (as described below). Reducing the volume of the foam, if relatively uniform, will also reduce the amount of fluid in place of compression. The rigidity of the foam in this case is lower than the capillary pressure exerted by the foam, so that the foam decreases in volume after the liquid has been removed by the beer to retain the core fluid. The capillary pressure here is dependent on the set foam cell size (which is inversely related to the ratio of surface area per unit volume). The strength is given by the combination of the density of the crosslinks and the density of the foam, which can be expressed as the density of the foamed bonds per unit volume. The type of cross-linking agent and types of other comonomers may also have an effect.

Suitable polymeric foams for this purpose include porous cellular foams. The cells of these porous cellular foams are equipped with intercellular apertures or "cavities" which, by their size, allow rapid transfer of fluid from one cell to another.

These porous cellular foams are generally characterized by a grid structure with individual cells delimited by a plurality of interconnected three-dimensionally branched crosslinks. For the purposes of the present invention, a foamed material is a porous cellular foam if at least 80% of the cells of the foamed material are at least 1 µm in size and are characterized by fluid communication with at least one adjacent cell.

In addition to being lightweight foams by nature, these polymer foams are sufficiently hydrophilic to absorb aqueous liquids. The inner surfaces of the foams are hydrophilic due to the residual hydrophilizing surface ·· ····

8 agents and / or salts left after polymerization in the foam, or as a result of the selected treatments described below following polymerization of the foam.

The degree of "hydrophilicity" of these polymeric foams can be quantitatively expressed by the value of the "adhesive stress" produced by contact with the absorbable test fluid. The adhesion stresses produced by the foams can be experimentally determined by a process whereby a weight gain of a test fluid, such as synthetic urea, is measured on a foam sample of known dimensions and known capillary suction surface area. This procedure is described in more detail in the Tests section of U.S. Patent No. 5,387,207, issued February 7, 1995, which is set forth in the appendix. The foams useful as the fluid distributors of the present invention are generally those in which the adhesive tension is from about 15 to about 65 dynes / cm, more preferably from about 20 to about 65 dynes / cm with an increase in capillary self-synthetic urine with a surface tension of 65 ± 5 dynes / cm.

An important aspect of these foams is their glass transition temperature (TSP), which is the midpoint of the transition between the glassy and flexible state of the polymer. Foams whose TSP is higher than the temperature at which they are used may be very strong but may also be very rigid and potentially susceptible to deterioration. Such foams are also characterized by tendencies to deformation under pressure and low resistance when used at temperatures cooler than the TSP of the polymer. The desired combination of mechanical properties, especially strength and durability, greatly limits the choice of monomer types and levels.

The TSP foams usable in the moisture distribution of the present invention should be as low as possible, up to acceptable strength. Accordingly, monomers whose corresponding polymers have a lower TSP value are preferably selected.

The shape of the glass transition region may also be important. if the shape is narrow or wide depending on the temperature. Particularly desirable is a shape where the operating temperature of the polymer (usually body temperature or ambient temperature) is identical to or very close to the TSP value. For example, a wider area of glass transition may mean that the transition is incomplete at operating temperature. In this case, the polymer usually exhibits greater rigidity and less flexibility. Conversely, if the transition at operating temperature is complete, the polymer will more easily return to its original form when pressure is released. We can see that it is desirable to be able to regulate the TSP value and the width of the transition region in order to achieve adequate mechanical properties of the polymer. In general, it is preferred that the TSP of the polymer be at least about 10 ° C lower than its operating temperature.

Polymer foams useful in the present invention can be described by a variety of parameters.

The polymeric foams useful for the purposes of the present invention are capable of sucking aqueous liquids to a considerable height upstream of gravitational forces, e.g., at least about 15 cm. The fluid column within the foam exerts a considerable precipitation capillary pressure. At a certain height of the column, which is given by both the rigidity of the foam (upon compression) and the surface area per unit of foam volume, the foam is compressed. This height gives the value of the capillary collapse pressure (TKK), expressed in cm, while 50% of the foam volume at zero initial pressure is lost. Preferred foams of the present invention will have a capillary collapse pressure of at least about 15 cm, more preferably at least about 20 cm, and even more preferably at least about 25 cm. Preferred foams of the invention will typically have a capillary collapse pressure of at least about 15 cm to about 50 cm, more preferably from about 20 cm to about 45 cm, and more preferably from about 25 cm to about 40 cm.

A parameter that may be useful in defining preferred polymeric foams is cell building. Foam cells, and in particular cells resulting from the polymerization of an oil phase monomer that surrounds relatively droplets of the monomer-free water phase, will often have substantially »»·· · · · · ··

-9-spherical shape. These spherical cells are interconnected by apertures, which are referred to herein as divisions between cells. Both the size or "diameter" of such spherical cells and the diameter of the holes (holes) between the cells are commonly used to characterize the foams in general. Since the cells and the holes between them do not necessarily have to be approximately the same size in a given polymer foam sample, the average cell and the hole size will often be specified, i. average cell and hole diameter.

Cells and particle sizes are parameters that can affect a number of mechanical and functional properties of these foams, including fluid absorbency and capillary pressure within the foam. The average cell size and aperture size of the foams can be determined in a number of ways. One of these is a simple measurement based on the scanning of a foam sample by an electron photomicrograph scanner. Foams suitable as aqueous liquid absorbents of the present invention will preferably have a plurality of average cells ranging in size from about 20 µm to about 60 µm. typically from about 30 µm to about 50 µm, and a plurality of average holes of about 5 µm to about 15 µηι. usually from about 8 µm to about 12 µπι.

"Capillary suction surface area" is the dimension of the surface area of the polymer network accessible to the test fluid, which is given by both the dimensions of the cellular units of the foam and the density of the polymer. In this way, the overall dimension of the solid surface of the foam which is involved in the absorption activity can be determined.

For the purposes of this invention, the capillary suction surface area is determined by measuring the volume of the capillary absorption of a low surface tension fluid (eg ethanol) that is performed on a foam sample of known volume and dimensions. For a detailed description of this procedure, see Tests in U.S. Patent No. 5,387,207 supra. Any other appropriate method of determining the exact capillary suction surface area may also be used.

Moisture distributing foams suitable for the present invention will preferably have a capillary suction surface area of at least about 0.01 m ² / ml, and more preferably at least about 0.03 m ² / ml. Typically, the capillary suction surface area will range from about 0.01 to about 0.20 m ² / mL, preferably from about 0.03 to about 0.10 m ² / mL, and most preferably from about 0.04 to about 0.08. m ² / ml.

The "foam density" (volume of foam in grams per cubic cm in air) is determined here on a dry basis. Foam density, as well as the precise surface area of the capillary suction, can affect a number of functions and mechanical properties of the absorbent foams, including the absorbent capacity for aqueous fluids and compression deflection properties. The density of the foam will vary depending on the state of the foam. The foams in the compressed state will obviously have a higher density than the same foams in the non-compressed state. The foams useful in the present invention will generally have a dry density of about 0.11 g / cm ³ in a compressed state.

Any suitable gravimetric procedure may be used to determine the amount of solid foam per unit volume of foam. For example, ASTM gravimetric analysis, described in more detail in the Tests section of U.S. Patent No. 5,387,207 supra, can be used to determine the density of the foam. The density of the foam is the weight of the unit of pure foam free of emulsifying agents, fillers, surfactants such as salts and the like. Foams suitable for the present invention will preferably have a dry density of from about 8 mg / cm ³ to about 77 mg / cm ³ , more preferably from about 11 mg / cm ³ to about 63 mg / cm ^3, and even more preferably from about 13 mg / cm ^3. cm ³ to about 48 mg / cm ³ .

Foams suitable for the purposes of the present invention can be obtained by polymerizing a certain water-in-oil (HIPE) emulsion with a relatively small amount of an oil phase and a relatively higher amount of an aqueous phase. The procedure consists of the following steps:

• fcfc fcfcfcfcfcfcfc fcfc fcfc fcfc fcfc fc fc fcfc fcfc fc

- 10A) forming a water-in-water emulsion at a certain temperature and precision shear mixing from the following components:

(1) the oil phase contains:

a) from about 85% to about 98% by weight of a monomer component capable of forming a copolymer having a glass transition temperature of about 35 ° C or less, the monomer component comprising:

(1) from about 30% to about 80% by weight of at least one substantially water-insoluble, single-functional monomer capable of forming an atactic amorphous polymer having a glass transition temperature of about 25 ° C or less;

ii) from about 5% to about 40% by weight of at least one substantially water insoluble monovalent comonomer capable of imparting a strength roughly equivalent to that mediated by styrene;

iii) from about 5% to about 3% by weight of a first substantially water-insoluble cross-linking polyfunctional agent selected from divinylbenzenes, trivinylbenzenes, divinyltoluenes, divinylxylenes, divinylnaflalenes, divinylalkylbenzenes, divinylphenanthrenes, divinylpheniphenylenes, diphenyldiphenyls, diphenyldiphenyls, diphenyldiphenyls, diphenyldiphenyls, woodfurans, divinylsulfides, divinylsulfones and mixtures thereof;

iv) from about 0% to about 15% by weight of a second substantially water-insoluble cross-linking polyfunctional agent selected from polyfunctional acrylates, methacrylates, akiylamides, methakiylamides and mixtures thereof;

b) from about 2% to about 15% by weight of an oil-soluble emulsifier component suitable for forming a stable water-in-oil emulsion, the emulsifier component comprising: (i) a major emulsifier with at least 40% by weight emulsifier components selected from diglycerínmonoesterů linearly unsaturations fatty acids with a chain _of C ₁₆ - C n · diglycerínmonoesterů branched fatty acids with a chain C _I6 - C ₂₄ diglycerínmonoalifatické ethers of branched alcohols having chain C _I6 - C ₂₄ diglycerínmonoalifatické etheiy linearly unsaturated fatty alcohols with chain C ₆ - C ₂₂ diglycerínmonoalifatické ethers of linear saturated alcohols with chain C ₁₂ - C ₁₄ sorbitan monoesters of linear unsaturated fatty acids with a chain C ₁₆ - C ₂₂ sorbitan monoesters of branched fatty acids with a chain C ₆ - C ₂ 4 , and mixtures thereof; or (ii) a combination of a major emulsifying agent with at least 20% by weight of said emulsifying ingredients and some secondary emulsifying agents in a weight ratio of the major and secondary emulsifying agents from about 50: 1 to about 1: 4; and

2) an aqueous phase in the form of an aqueous solution comprising: (i) from about 0.2 to about 20% by weight of a water-soluble electrolyte; and (ii) an effective amount of a polymerization initiator;

3) a water to oil phase weight ratio ranging from about 12: 1 to about 125: 1; and

B) polymerizing the monomer component in the oil phase of the water-in-oil emulsion to form a polymeric foam; and

(C) de-watering the polymeric foam, if any.

This procedure allows the formation of absorbent foams which are capable of distributing moisture due to the carefully selected properties described herein. These were achieved by careful selection> 9 • »

- 11 types and levels of monomer and component to form cross-links, by selecting the parameters to form the emulsion (especially the degree of shear mixing, temperature and water-in-oil ratio - which is transferred to the final dry foam density).

Polymer foams suitable for the purposes of the present invention can be made by polymerizing some emulsions with a relatively high water to oil ratio. This procedure is known in the art by the abbreviation "HEPE". The polymer foams thus produced are referred to herein as "HIPI foams?" and a detailed description of the general procedure is given in US Patents 5,563,179 and 5,387,207 infra.

The relative amount of water and oil phase used in the manufacture of HIPE foams, along with other parameters, is important for determining the structural, mechanical, and functional properties of the resulting foams. In particular, the water to oil ratio (V: O ratio) in the emulsion varies indirectly with the final foam density and can affect cell size, the exact surface area of the capillary suction and the dimensions of the foam forming tubes. Emulsions used to prepare HIPE foams suitable for the present invention will generally have a water to oil phase weight ratio ranging from about 12: 1 to about 125: 1, most typically from about 15: 1 to about 90: 1. Particularly preferred HIPE foams having a ratio of both phases of from about 20: 1 to about 75: 1.

The major part of the oil phase of HIPE foams will contain monomers, comonomets and crosslinking components, see US Patent 5,387,207 infra. It is essential that these monomers, comonomers and crosslinking components be substantially insoluble in water so that they are primarily soluble in the oil phase and not in the water phase. The use of these substantially water-insoluble monomers ensures that the desired characteristics and stability of the HEPE foams are achieved. It is of course highly desirable that such monomers, comonomers, and crosslinking components be of a type such that the resulting polymeric foam is non-toxic and chemically stable accordingly. These monomers, comonomers and foam bonding components should preferably exhibit little or no toxicity as long as they remain present at very low residual concentrations upon subsequent treatment or use of polymerized foam.

Another essential component of the oil phase is an emulsifying component that allows the stability of the HIPE foams to be achieved. This component contains a primary emulsifier component and optionally a second emulsifier component - see U.S. Pat. No. 5,387,207 infra.

The oil phase used to prepare the HIPE foams comprises a monomer of from about 85% to about 98% by weight and an emulsifier from about 2% to about 15%. Preferably, the oil phase will comprise a monomer of from about 90% to about 98% by weight and an emulsifier from about 3% to about 10%. The oil phase may also contain other optional components. One such optional component is an oil-soluble polymerization initiator of the general type well known to those skilled in the art (see U.S. Pat. No. 5,290,820 of March 1, 1994, which is appended). Another preferred optional ingredient is an antioxidant, such as Hindered Amine Light Stabilize (HALS), Hindered Phenolic Stabilizers (HPS) or any other antioxidant compatible with the initiator to be used. Other optional ingredients include plasticizers, fillers, dyes, chain transfer agents, solubilized polymers, and others.

The discontinuous aqueous internal phase of HEPE foams is generally an aqueous solution containing one or more dissolved components - see US Patent 5,387,207 infra. One essential dissolved component of the aqueous phase is a water-soluble electrolyte. The dissolved electrolyte reduces the tendency of the monomers, comonomers and components to form cross-links (which are mainly oil-soluble) to also dissolve in the aqueous phase.

It to it it to it it to this it to it this to it this to it ··· • • to ·

In contrast, in our opinion, the degree of filling of the cell windows with polymer mass at the oil-water interfaces formed by the water phase droplets during polymerization is reduced. The presence of the electrolyte and the resulting ionic strength of the aqueous phase thus determine, in our opinion, whether and to what extent the resulting polymer foams may take the form of expanded porous foams.

HIPE foams will also normally contain a polymerization initiator. This component is generally added to the aqueous phase of these foams and can be any conventional water-soluble free radical. These include peroxygen compounds such as sodium, potassium and ammonium pyrosulfates, hydrogen peroxide, sodium peracetate, sodium percarbonate and others. Conventional redox initiation systems may also be used. These systems consist of a combination of said peroxygen compounds with reducing agents such as sodium bisulfite, L-ascorbic acid or ferrous salts.

The initiator may be present up to about 20 mole percent of the total number of gram polymerizable monomer molecules present in the oil phase. More preferably, the initiator is present in an amount of from about 0.001 to about 10 mole percent of the total number of gram polymerizable monomer molecules present in the oil phase.

The polymer that forms the HIPE foam structure will preferably not contain polar functional groups. That is, the nature of the polymer foam will be relatively hydrophobic. These hydrophobic foams may find use where absorption of hydrophobic fluids is desired. Possible uses include those where the oil component is mixed with water and where it is desirable to separate and isolate the oil component, as is the case with oil product spills into the sea.

Where these foams are to be used as absorbents of aqueous liquids (juice, milk stains, etc.) for cleaning or suctioning of body fluids (such as urine), further processing is generally required to make the foam more hydrophilic. Hydrophilization of the foam may, if necessary, be accomplished by treating the HIPE foam with a hydrophilizing surfactant as described in U.S. Patent No. 5,387,207.

The hydrophilizing surfactant may be any substance which increases the wettability of the surface of the polymer foam with water. Numerous similar surfactants are known in the art, preferably of the non-ionic type - see U.S. Patent No. 5,387,207 to measure.

Another substance that is usually added to the HIPE foam structure is a hydratable and preferably hygroscopic or melting water-soluble inorganic salt. Such salts include, for example, acidic earth metal salts which are toxicologically acceptable. Salts of this type and their use together with oil-soluble surfactants (such as foamed hydrophilizing surfactants) are described in more detail in U.S. Patent No. 5,352,711, Sep. 4, 1994, the description of which is appended hereto. Preferred salts of this type include calcium haloids such as calcium chloride (as already mentioned, calcium chloride can also be used as an electrolyte in the aqueous phase).

Hydratable inorganic salts can be easily incorporated by treating the foams with an aqueous solution of these salts. These saline solutions can generally be used to treat foams upon completion or as part of the process of removing residual water phase from just polymerized foams. Treatment of the foams with these solutions preferably results in the deposition of a hydratable inorganic salt such as calcium chloride in a residual amount of at least about 0.1% by weight of the foam, typically in the range of about 0.1 to 12%.

Treatment of these relatively hydrophobic foams with hydrophilizing surfactants (with or without hydratable salts) will usually be performed to the extent necessary to impart adequate hydrophilicity. However, some preferred HIPE foams are suitably hydrophilic upon manufacture and may contain sufficient amounts of hydratable salts so that they do not require any additional hydrophilizing surfactant treatment or hydratable surfactants.

-13salt. Such preferred HIPE foams include those wherein certain oil phase emulsifiers and calcium chloride are already used in the manufacture. In such cases, the internal polymerized foam surfaces will be correspondingly hydrophilic and will comprise a residual aqueous phase fluid containing sufficient amounts of calcium chloride, even after deposition of the polymeric water foams to the usable state.

Foam production usually consists of the following steps:

1) forming a stable high internal phase emulsion (HIPE);

2) polymerizing / curing the stable emulsion under conditions suitable to form a solid polymeric foam;

3) optionally washing out the solid polymeric foam to free from the original residual water phase and, if necessary, treating the polymeric foam with a hydrophilic surfactant or hydratable reindeer to apply any necessary hydrophilizing surfactant to the hydratable salt; and

4) then dewatering the polymeric foam. The entire process is described in more detail in US Patent 5,387,207 supra.

Absorbents

The compounds of the present invention are suitable for a variety of moisture distribution applications (i.e., suction, distribution, release), but are particularly suitable for use in absorbent compositions.

In order to use the appropriate materials in absorbent materials, these materials can be combined with other elements to form a moisture distribution element comprising the materials described above.

The absorbent article typically comprises:

an absorbent core or core structure (with the improved moisture distribution elements of the present invention, which may consist of sub-elements);

a liquid pervious top surface; a liquid impermeable bottom surface;

optional additional parts such as attachment means or elastic compliance means.

6 is a plan view of an exemplary embodiment of an absorbent article of the present invention having a diaper function;

The diaper 20 of Figure 6 is shown in unfolded, non-warped form (with the elastic pads removed except for the side panels where the pads are left in a relaxed state). The diaper portions, including the back portion, are cut out to more clearly illustrate the structure of the diaper 20. The diaper 20 includes a containment assembly 22, which further preferably includes a liquid pervious top surface 24, a liquid impermeable bottom surface 26 that is joined to the top surface 24, an absorbent core 28 that is sandwiched between the top surface 24 and the bottom surface 26, the elastic side panels 30, the elastic leg cuffs 32, the elastic waist 34 and the fastening means 36.

The dual voltage switching system 36 preferably includes a primary switching system 38 and a waist-fastening system 40. The waist-fastening system 40 preferably includes a pair of first fastening portions 46 and a second fastening portion 48. The diaper 20 also preferably has Velcro fasteners 50 adjacent to it. of each first clamping member 46.

Further components of the diaper 20 of Figure 6 further include an outer surface 52 (facing the viewer's eyes), an inner surface 54 that faces the outer surface 52, a first waist portion 56, a second waist portion 58 that is opposed to the first waist portion 56, and the rim 60 defined by the outer rims of the diaper 20, i. longitudinal rims 62 and transverse rims 64. The inner surface 54 of the diaper 20 includes that portion of the diaper 20 that, when in use, abuts the skin of the wearer (i.e., the inner surface 54 generally comprises at least a portion of the upper surface 24 and . The outer surface 52 includes that portion of the diaper 20 that is positioned outside the user's body (i.e., the outer surface 52 generally comprises at least a portion of the bottom surface 26 and other parts joined to the bottom surface). The first waist portion 56 and the second waist portion 58 extend from the transverse edges 64 of the rim 60 to the transverse centerline 66 of the diaper 20. Both waist portions include a central portion 68 and a pair of side panels, and usually the outer longitudinal portions of the waist portions. The first portion of the waistband 56 includes side panels 70 and the second portion of the waistband 58 the side panels 72. It is not necessary that the two pairs of side panels be identical, but preferably represent a mirror image of each other. The side panels 72 in the second waist portion 58 may be resiliently extensible in the transverse direction (i.e., the resilient side panel 30). The transverse direction x (or width) is defined as the direction parallel to the transverse centerline 66 of the diaper 20, the longitudinal direction y (or length) is defined as the direction parallel to the longitudinal centerline 67 and the axial direction z (thickness) is defined by the direction 20 May

Figure 6 shows the diaper 20 with the length and width of the top 24 and the bottom surface 26 greater than the dimensions of the absorbent core 28. The top 24 and the bottom surface 25 overlap the edges of the absorbent core 28 to form the edge 60 of the diaper 20. , ie. its longitudinal 62 and transverse flanges 64.

Although both elastic leg cuffs 32 may resemble a thigh collar, side flaps, or support cuff, each preferably includes an inner abutment cuff 84, a support flap 85, and a spatial elastic member 86 (see U.S. Pat. No. 4,909,803). In a preferred embodiment, a further component of the elastic cuff 32 is an elastic sealing cuff 104 including one or more elastic strips 105 located outside the support cuff 84 (see the aforementioned U.S. Patent 4,695,278).

A further component of the diaper 20 may be an elastic waist feature 34 that allows better fit and grip. The elastic waist feature 34 extends longitudinally outwardly from at least the waist flanges 83 of the absorbent core 28, at least in the middle portion 68, and typically forms at least a portion of the transverse hem 64 of the diaper 20. Thus, the elastic waist feature 34 includes a portion of the diaper that extends from the waist hem 83 of the absorbent core 28 to the transverse hem 64 of the diaper 20 and is intended to be positioned around the waist of the wearer. Disposable diapers are generally made with two elastic waistbands, one positioned in the first waist portion and the other in the second waist portion.

The elastic waistband 35 of the elastic waist member 34 may comprise a portion of the upper surface 24, a portion of the lower surface 26 that has been mechanically tensioned ⁷ , a bilayer mass including an elastomeric member 76 interposed between the upper 24 and lower surface 26, and a resilient member 77 interposed between the surface 26 and the elastomeric member 76.

These and other diaper parts are described in more detail in WO 93/16669, which is included in the appendix.

• ·

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Absorbent core

The absorbent core should generally be compressible, supple, non-irritating to the skin and capable of absorbing and retaining liquids such as urine and other body exudates. It can be seen from Figure 6 that the absorbent core includes a garment-facing surface ("lower" or "lower"), a body-facing surface, side edges and waist edge. The absorbent core may include, in addition to the fluid distribution element of the present invention, a variety of absorbent and moisture handling agents commonly used in disposable diapers and other absorbent articles such as but not limited to pulverized wood , fused flat polymers, chemically stiffened, treated or crossed pulp fibers, fabrics including fabric padding and layered fabrics.

General examples of absorbents are described in U.S. Patents 4,610,678, 4,673,402, 4,888,231, and patent applications EP-A-0,640,330, US 5,180,622 and US 5,387,207. These and the like can be considered comparable to the absorbent core 28 requirements set forth below.

The absorbent core may be in the form of a unitary whole, or it may be a combination of several absorbent substances which consist of one or more sub-units. Each of these or sub-units may be two-dimensional (i.e. in the form of a layer) or three-dimensional.

Parts of absorbent articles

Absorbent sanitary articles are generally intended to be worn on the lower torso. The main functional feature of these devices is to cover the body parts where excretion occurs, ie. body parts around the respective body openings. Corresponding parts of the absorbent article are referred to as " filling areas ". In use, the position of the absorbent means is generally such that, when the wearer is in an upright position, the absorbent means is pushed upward in its crotch, both front and rear.

These means are generally elongated in shape, i. that the length dimension exceeds the width dimension. The device is worn such that the axis of the longitudinal dimension is parallel to the dimension of the height of the user in its upright position and the axis of the transverse dimension is parallel to the line drawn from the left to the right through the body of the user.

For anatomical reasons, the space between the legs of the wearer defines the space for receiving the absorbent article. The absorbent article should be adapted to fit well in the crotch region. If the device is too wide with respect to the crotch width of the user, the device may be deformed, resulting in a deterioration in its functionality and a deterioration of the user's comfort.

The place where the absorbent is the narrowest coincides with the place on the body where the distance between the legs is narrowest. We call this place "the crotch point" for the purposes of our invention.

The crotch point is not always necessarily in the middle of the absorbent article. The appearance of the absorbent article may be such that its anterior portion is smaller than the posterior portion - either longitudinally, transversally, both, or at the surface area. The crotch point also need not be in the middle of the absorbent core, especially in those cases where the absorbent core is not longitudinally in the middle of the absorbent article.

The crotch portion is in the area surrounding the crotch point so as to cover the respective body openings, i. excretions. Unless otherwise stated, this portion covers 50% of the total length of the core in the longitudinal direction (this is defined as the distance between the front and rear hem • ·

of the core waist, which may be represented by straight lines and rectangular lines relative to the longitudinal centerline). If the crotch point is in the middle of the absorbent article, then the crotch portion begins (calculated from the front hem of the core) at 25% and covers 75% of the total length of the core. In other words, the front and back quarters of the length of the absorbent core are not counted to the crotch portion.

This length of the crotch portion (i.e. 50% of the total length of the absorbent core) was derived for diapers, which in our view are a suitable means of representing the effects of moisture handling. If the present invention is used for compositions with significantly different dimensions, it may be necessary to reduce or increase the ratio by 50%. More generally, the crotch part should not exceed the user's discharging part too much.

If the crotch point is not identical to the center point of the absorbent article, the crotch portion still covers 50% of its total length (in the longitudinal direction) but is not evenly positioned between the front and back portions.

In the case of an absorbent article having a crotch point at the center and a total core length of 500 mm, the crotch portion will extend from 125 mm from the front hem to 375 mm from the hem. If the crotch point is deflected 50 mm towards the front edge of the core (i.e., at a distance of 200 mm from the front edge of the core), the crotch portion will be guided 100 mm to 350 mm from the front edge of the core.

Generally, if a total absorbent core length of L _c, a crotch point distance Lc _P from the luff and the core crotch region length of L _cz, the front edge of the crotch region located at a distance

Lfecz ^- L _cp (2 - L _cz i L _c )

The absorbent may be, for example, a baby diaper intended for toddlers (i.e., a weight of about 12-18 kg), the size of which is commercially generally referred to as MAXI size. The absorbent must in this case be capable of holding and retaining both faeces and urine, and in the context of the present invention, the crotch portion must be able to receive primarily the total volume of urine.

The total area and size of the crotch portion also depends, of course, on the width of the absorbent core, i. if the core in the crotch portion is narrower than outside the crotch portion, the area of the crotch portion is smaller than the remaining area of the absorbent core.

Although we may consider the possibility of curved edges between the crotch portion and the remainder of the absorbent article, for purposes of the present invention, they are in line with this description straight lines forming a right angle with the longitudinal axis of the absorbent article.

The "crotch area" is further defined by the width of the kernel in the area concerned, and the "crotch area" is given by the length of the crotch area and its width.

In the function of the complementary crotch portion, the absorbent core may also comprise at least one, but mostly two, waist portions extending beyond the crotch portion of the front and rear outside the absorbent core.

Estimated capacity and final capacity

In order to compare end-use absorbent articles or absorbent articles of different sizes, we have determined "predicted capacity" as the appropriate common measure.

• ·

A typical user group is, for example, children, but within this group, the amount of urine volume, the rate of excretion and the composition of urine will vary considerably between newborns and toddlers on the one hand, but also between children.

Another user group may be larger children who still suffer from some form of wetting.

These agents can also be used by adults, again with a whole range of difficulties.

It will certainly not be a problem for the practitioner to convert the discussed sizes to other sizes, and we will focus on children of toddler age. In toddlers, we found urine levels with one rectum empty up to a volume of 75 ml, with an average of four voids per absorbent wear period. This means a total filling volume of 300 ml and a volume diameter of 15 ml / sec.

In order to meet these requirements, absorbent articles must be able to accommodate these amounts of urine, which will be referred to as "predicted capacity".

These amounts of fluids must be absorbed by the materials that can safely retain them, or at least the aqueous parts thereof, so that only a small amount of fluid remains in the worst case on the skin-absorbent surface. The term 'final capacity' here refers both to the situation of wearing the absorbent article for a long period of time without replacement, and to absorbents which reach their final capacity after equilibrium with the environment. Thus, it may relate to absorbent compositions under real-life conditions over long periods of wear, or also to test procedures for pure substances or combinations thereof. Because many of the processes examined have an asymptotic kinetic waveform, the skilled artisan will understand a "finite capacity" value where the actual capacity is sufficiently close to the asymptotic endpoint.

The absorbent article may comprise substances primarily intended to ultimately retain fluids and other substances intended primarily to perform other functions, such as aspiration and / or fluid distribution, but which may not have the ultimate fluid acquisition capability. For this reason, suitable absorbent core materials according to the invention are described herein without attempting to separate these functions. However, the degree of ultimate entrapment capability may be derived for the entire absorbent core, its portions, absorbent substances, partial substances, and all substances used.

It will not be a problem for the person skilled in the art to adjust the appropriate predicted capacities for other user groups (see the various sizes of absorbent articles mentioned above).

Substances applicable to absorbent cores

The absorbent core may comprise fibrous webs in the form of fibrous webs or fibrous matrices.

Suitable fibers include natural fibers (treated or untreated) as well as synthetically produced fibers. Suitable treated / untreated natural fibers include cotton, esparto grass, sugarcane, hemp, flax, silk, wool. pulp, chemically treated pulp, jute, rayon, ethylcellulose and cellulose acetate. For the production of the corresponding synthetic fibers, polyvinyl chloride, polyvinyfluoride, polytetrafluoroethylene, polyvinylidene sulfide, polyacrylates such as ORLON®, polyvinyl acetate, polyethylene vinyl acetate, insoluble or soluble polyvinyl alcohol, polyolefins such as polyethylene (e.g. PULPEX®) and polypropylene, polyamide, DACRON® or KODEL®, polyurethanes, polystyrenes and others. The fibers may consist solely of natural fibers, solely of synthetic fibers or

- 18 • · · · · · · ·

any compatible combination of natural and synthetic fibers. The fibers used in the present invention may be hydrophilic or a combination of both hydrophilic and hydrophobic fibers.

Hydrophilic fibers are preferred for many types of absorbent cores. These include pulp fibers, treated pulp fibers, rayon, polyester fibers such as poly (ethylene terephthalate) (e.g., DACRON ®), hydrophilic nylon (HYDROFIL ®), and others. Suitable hydrophilic fibers can be obtained by hydrophilizing hydrophobic fibers such as a surfactant or silica treated thermoplastic fibers derived from materials such as polyolefins - polythylene, polypropylene, polyacryls, polyamides, polystyrenes, polyurethanes and others.

Suitable pulp fibers can be obtained by many known chemical processes, including but not limited to Kraft and sulfite processes. Another suitable type of fiber is chemically stiffened pulp. The term "chemically stiffened pulp fibers" in this context means pulp fibers that were. reinforced with chemical agents to increase fiber stiffness, both in dry and humid environments. Such procedures may include the addition of a chemical reinforcing agent which, for example, impregnates and / or impregnates the fibers. Further, these processes may include stiffening the fibers by altering the chemical structure, e.g., by crosslinking the polymer fibers.

Polymeric stiffeners that may cover or impregnate the pulp fibers include: cationically modified starches with nitrogen containing groups (eg, amino groups), latexes, wet-strength resins (eg, Kymene® 557H polyamideepichlorohydrin resin, Hercules, Inc. Wihnington, Delaware) , USA), polyacrylamide resins (described, for example, in U.S. Patent 3,556,932), commercially available polyacrylamides distributed under the trade name Parez® 631 by American Cyanamid Co. Stamford, CT, USA, urea formaldehyde and melamine formaldehyde resins and polyethylene amine resins.

These fibers can also be stiffened by a chemical reaction. For example, the cross-linking agent may be used such that, upon application, cross-linking crosslinks are chemically formed to enhance the stiffness of the fibers. Although the use of inter-fiber cross-links is preferred, this does not mean excluding other types of chemical stiffening reactions.

Procedures for preparing individual stiffened fibers by cross-linking are described, for example, in U.S. Patents 3,224,926, 3,440,135, 3,932,209, 4,035,147, 4,989,642d and 5,137,537.

In the presently preferred stiffening process, the fibers are subjected to chemical treatment, including cross-filament cross-linking, by means of cross-linking agents, wherein the fibers are in a relatively dehydrated, defibrillated (i.e., discrete) and twisted state. Suitable chemical ztužovadlům monomer usually include reagents enabling the crossover, including in particular C ₂ - C ₉ polycarboxylic acids such as citric acid. The mechanical treatment of such stiffened fibers is preferably described in the US patent

4.898.642.

These chemically stiffened pulp fibers have certain properties with respect to non-stiffened pulp fibers which make them particularly suitable for use in certain absorbent articles. In addition to being hydrophilic, these fibers have remarkable combinations of strength and elasticity.

In addition or alternatively to the above, synthetic or thermoplastic fibers, for example made of any thermoplastic polymer that can be melted at temperatures that do not substantially interfere with the fibers, may be included in the absorbent materials. The melting point of such a thermoplastic mass will preferably be less than about 190 ° C and preferably between about 75 ° C and 175 ° C. In any case, the melting point of the thermoplastic should not be lower than the likely storage temperature of the absorbent articles containing the thermally bonded absorbent. The melting point of thermoplastics is generally not less than about 50 ° C.

· · · * * * * * * * * * * * * * * * * * * * *

Thermoplastic materials and especially thermoplastic fibers can be made from a variety of thermoplastic polymers, including polyolefins such as polyethylene (e.g., PULPEX®) and polypropylene, polyesters, copolyesters, polyvinyl acetate, polyamides, copolyamides, polystyrenes, polyurethanes and copolymers of all such materials. is vinyl chloride / vinyl acetate and others. Suitable thermoplastic materials include hydrophobic fibers which have been made hydrophilic, such as a surfactant or silica treated thermoplastic fibers, derived, for example, from polyolefins such as polythylene or polypropylene, polyacryls, polyamides, polystyrenes, polyurethanes, and others. The surface of the hydrophobic thermoplastic fibers can be made by hydrophilic treatment with a surfactant, such as a nonionic or anionic surfactant, eg by spraying the fibers with the surfactant, immersing the fibers in a bath or incorporating the surfactant as part of the polymer melt in thermoplastic fibers. Upon melting and re-solidification, the surfactant will tend to remain on the surface of the thermoplastic fibers. Suitable surfactants include nonionic agents such as Brij® 76, manufactured by ICI Americas, Inc. of Wilmington, Delaware, and other reagents sold under the trademark Pegosperse® by Glyco Chemical, Inc. of Greenwich, Connecticut. In addition to nonionic surfactants, it is also possible to use anionic surfactants. This can be applied to the thermoplastic fibers at levels of, for example, from about 0.2 to about 1 g / cm ^{2 of} thermoplastic fibers.

Suitable thermoplastic fibers can be made from a single polymer (monocomponent fibers) or from more than one polymer (eg, bicomponent fibers). Bicomponent fibers are, for example, thermoplastic fibers whose core is made of a single polymer enclosed in a thermoplastic sheath made of a different polymer. The sheath polymer often melts at a different (usually lower) temperature than the core polymer. As a result, these bicomponent fibers allow thermal bonds by melting the sheath polymer while maintaining the desired strength of the core polymer.

Suitable bicomponent fibers include core-type fibers containing the following polymer combinations: polyethylene / polypropylene, polyethyl vinyl acetate / polypropylene, polyethylene / polyester, polypropylene / polyester, copolyester / polyester, and others. Particularly suitable bicomponent thermoplastic fibers for use in the present invention are fibers with a polypropylene or polyester core and a copolyester, polyethylene, or polyethylene sheath (e.g., DANAKLON®, CELBOND® or CHISSO®). These bicomponent fibers may be concentric or eccentric, depending on whether the core sheath is uniform or uneven in thickness. Eccentric bicomponent fibers may be suitable because of greater resistance to compression at lower fiber thickness. Both types of bicomponent fibers may be "uncombed" for the purposes of the present invention. The bicomponent fibers may be combed by conventional textile mechanical means to provide predominantly a "two-dimensional" or "flat" fiber placement.

In the case of thermoplastic fibers, their length may vary according to the melting point and other desirable properties. These thermoplastic fibers generally have a length of from about 0.3 to about 7.5 cm, preferably from about 0.4 to about 3.0 cm. The properties of the fibers - including the melting point - of these thermoplastic fibers can also be adjusted by changing the diameter (caliper) of the fibers. The diameter of these thermoplastic fibers is usually referred to as denier (g per 9,000 m) or decitex (g per 10,000 m). In the context of different structure configurations, suitable thermoplastic fibers may have a decitex of less than 1 dtex (e.g., 0.4 dtex) to about 20 dtex.

The fibrous masses of the individual fibers can be used in the manufacture of an absorbent composition by spraying the fibrous mass onto a production line. These fibers can also be used in the form of preformed fibrous web or fabric, which are further processed necessarily over a considerable length (e.g.

-20 rolls or reels) and are cut to size during the process. Each substance can thus be treated individually before being combined with other parts to form an absorbent core, or after combining with other parts.

Methods for making such webs are numerous and well known in the art.

Due to the applicability of the fibers in the manufacture of these webs - in principle, there are hardly any limitations, although certain pressing and binding processes of the webs may not be fully compatible with certain masses or types of fibers.

In the manufacture of netting from individual fibers, these fibers may be contained in a mobile medium - if the medium is gaseous (air), the production of such netting is generally referred to as "dry deposit"; like “wet I save”. "Wet deposit" is very often used in the manufacture of paper fabrics with a variety of properties. This term is most commonly used in connection with pulp masses, but may also refer to synthetic fibers.

"Dry deposition" is widely used in the context of nonwoven netting.

The molten polymer can be extruded into fibers, from which it is then possible to directly form the web (i.e., the step of forming the individual fibers from which the web is then formed is omitted). The resulting compositions are commonly referred to as meltblown type nonwoven webs.

Mesh can also be produced by combining other production technologies.

For reasons of certain strength and integrity, netting is generally carried out. The most commonly used processes are (a) chemical bonds or (b) melting portions of the formed thermal bonds. In the latter case, the fibers may be compressed, resulting in significant bonding points that may cover (e.g., nonwoven) a significant portion of the total area - 20% is no exception. Or, where low-density masses are desired, air-through binding can be used, where parts of the polymer (e.g., BiCo sheath mass) are melted by means of heated air that is routed through the mesh.

The molded and interwoven webs can be further processed to obtain precise properties. It is possible - as one example of many possibilities - to expose them to an additional surfactant which will make the hydrophobic fibers more hydrophilic, etc. The webs can also be processed post-mechanically to give them particularly advantageous properties - see patent application EP 96108427.4.

The absorbent cores may comprise, in addition to or alternatively to the fibrous webs, other porous materials, such as foams, in particular open cell absorbent polymeric foams as described above.

Superabsorbent polymers or hydrogels

Optionally and often preferably, the absorbent materials of the present invention may comprise superabsorbent polymers and / or hydrogels. The hydrogel absorbent polymers useful in the present invention include a number of substantially water-insoluble but water-swellable polymers capable of absorbing large quantities of liquids. These polymer masses are also commonly called "hydrocolloids" or "superabsorbent" masses. These hydrogel-forming absorbent polymers are preferably characterized by multiple anionic functional groups such as sulfonic acid, or more typically, carboxyl groups. Suitable polymers include those made from polymerizable acid-containing unsaturated monomers.

Certain non-acidic monomers may also be included in the preparation of the hydrogel-forming absorbent polymers, usually in small amounts. Such non-acidic monomers may include, for example, water-soluble or water-dispersible aesthetics of acid-containing monomers as well as monomers which do not contain any carboxylic or sulfonic acid groups at all. Examples of such well known compositions are described, for example, in U.S. Patents 4,076,663 and 4,062,817.

Suitable hydrogel-forming absorbent polymers for use herein include carboxyl groups. These polymers include hydrolyzed graft copolymers of starch-acrylonitrile copolymers, partially neutralized graft copolymers, starch-acrylonitrile graft copolymers, starch-acrylic acid, partially neutralized copolymers ⁷ starch-acrylic acid copolymers, saponified vinyl acetate-acrylic ester copolymers, hydrolyzed acrylonitrile or acrylamide, slightly cross-linked polymers of any of the foregoing copolymers, partially neutralized polyacrylic acid, and slightly crosslinked polymers of partially neutralized polyacrylic acid. These polymers can be used either alone or in the form of a mixture of two or more different polymers. Examples of these polymer compositions are described in U.S. Patents 3,661,875, 4,076,663, 4,093,776, 4,666,983, and 4,734,478.

Most of the advantages of polymeric compositions suitable for making hydrogel-forming particles are slightly cross-linked polymers of partially neutralized polyacrylic acids and their starch derivatives. The hydrogel-forming particles preferably contain from about 50 to about 95% and preferably about 75% neutralized and cross-linked polyacrylic acid (i.e. poly (sodium acrylate / acrylic acid)).

As already mentioned, the hydrogels forming the absorbent polymers are preferably slightly cross-linked. Crossing the grid makes the polymer substantially insoluble in water and partially determines the absorption capacity and releasable properties of the polymer content of the precursor particles and the resulting macrostructures. The procedures for forming cross-linked polymer lattices and typical cross-linking agents are described in more detail in the aforementioned U.S. Patent 4,076,663.

The superabsorbent compositions can be used in bulk or fibrous form and can also be combined with other elements to form a tablet.

The absorbent structure and / or sub-structure may be formed by combining one or more beers that have been described separately.

Description of suitable combinations will follow (without limiting the list thereof).

i) Loose Superabsorbent Polymer (SAP), blended with pulp or other fibers. The basic principle is well known - after attempts to reduce the thinness of the formulations, increasingly higher and higher ratios of SAP weight relative to the amount of fibers have recently been used. Within this framework, combining SAP with a binder such as hot-melt adhesives (see EP-A-0.695.541) or a meltable polymer mass (such as PE particles) may be a suitable means of immobilizing SAP;

(ii) SAP forming the substructure by cross-particle intersection;

(iii) SAP in fiber form mixed with other fibers or in the form of fiber SAP mesh;

iv) foam structures containing superabsorbent bulk materials.

• fc fcfcfcfc · fcfcfc

-22Examples

These examples illustrate the precise preparation of HIPE compressed foams suitable for the purposes of the present invention.

Samples 1, 2, 3 - HIPE foams as a moisture distribution agent

The following samples A. 5 - A. 7 are polymeric foams and are made as described in the general description in the Examples section of US Patent 5,563,179 supra. The process generally involves adequately mixing an aqueous phase containing selected salts with an oil phase containing selected monomers and emulsifying agents. The aqueous phase typically comprises an initiator such as potassium persulfate and an inorganic salt such as hydrated calcium chloride. The oily phase typically comprises a mixture of monomers (eg, 2-ethylhexyl acrylate) and cross-linked monomers (eg, divinylbenzene, which contains ethyl styrene as an impurity, and 1,6-hexanediol diacrylate). Adjuvants (eg, antioxidants, turbidity, pigments, dyes, fillers, and other non-reactive chemicals) may also be added to both phases.

The separated oil and water phase streams (usually heated to between about 30 ° C and 90 ° C) are fed to a dynamic mixer where complete mixing is performed mechanically. The density level of the final foam produced is determined by the ratio of water to oil phase (water to oil ratio - W: O). For a detailed description of the devices and processes for producing HIPE foams, see Examples of US Patent 5,563,179 supra.

After the mixing device is filled, dynamic mixing is started with the impeller rotating at a certain speed given in rpm. The water phase flow diameter is then evenly increased to 44.1 cm ³ / sec over a period of about 30 seconds, the oil phase flow diameter is reduced to 1.25 g / sec over a period of about 1 minute. The back pressure created by the dynamic and static mixer at this point is from about 21 to about 55 kPa. The drive is then set to the desired speed for 120 seconds. The system back pressure is adjusted to this setting and remains constant thereafter.

The HIPE is removed from the static mixer into a polypropylene tube (43 cm diameter and 10 cm high) with a concentric Celcon insert. The diameter of the insert at its base is 12.7 cm, at its top at a height of 17.1 cm has a diameter of 12 cm. The HIPE-containing polypropylene tubes are then stored in a 65 ° C room for 18 hours to cure the HIPE polymer foam.

After curing, the HIPE foam is removed from the tubes. The foam at this point contains a residual aqueous phase (containing dissolved emulsifying agents, electrolyte and initiator residues). This is cut into slices of the desired thickness, which are then subjected to compression by a series of two perforating vacuum rollers which gradually de-foam the residual water phase up to twice the weight of the polymerized monomers. At this point, the slices are rewetted with a 4% CaCl solution at 60 ° C and then again subjected to compression by a series of three perforating vacuum cylinders with a loss of residual water phase to twice the weight of the polymerized monomers. _CaCl2 content of the foam is between 2 and 10%.

The HIPE foam is then exposed to air for 16 hours or is subjected to continuous drying, resulting in a moisture content of about 4-20% by weight of the polymerized mass.

4

4 44

-23Sample 1

Anhydrous calcium chloride (36.32 kg) and potassium persulfate (189 g) are dissolved in 378 L of water. This is the source of the water phase that will be continuously fed when the HEPE emulsion is formed.

Kmonomer combination (distilled divinylbenzene (39% divinylbenzene and 61% ethylstyrene) 2.640 g, 2-ethylhexyl acrylate 4.720 g, hexanediol diacrylate 640 g) is added diglycerol monooleate emulsifying agent (480 g), ditallow dimethyammonium methylsulfonate (80 g) dimethyl sulphate ). The diglycerol monooleate emulsifier (Grindsted Products, Brabrand, Denmark) contains approximately 81% diglycerol monooleate. 1% additional diglycerol monoesters, 3% polyols and 15% other polyglycerol esters) is a source of a minimum interfacial tension of approximately 2.7 dynes / cm and is characterized by a critical oil and water agglomeration concentration of approximately 2.8 wt%. After mixing, this combination of substances is allowed to settle for a few hours. No visible residue was formed and the entire volume of the mixture was used as the oil phase during the manufacture of the HEPE emulsion.

Separate oil phase (25 ° C) and water phase (53-55 ° C) streams are fed to a dynamic mixing device. Thorough mixing of the two streams in the dynamic mixer is accomplished by means of a spike actuator in the form of a cylindrical shaft about 36.5 cm long with a radius of about 2.9 cm. There are 6 rows of spikes, 3 rows of 33 spikes and 3 rows of 34 spikes on the shaft, each with 3 spikes at an angle of 120 ° to each other, with each level offset by 0.03 mm and its spikes gripping with adjacent spikes 60 degrees. Each spike has a diameter of 0.5 cm and extends outward from the central axis of the shaft to a distance of 2.3 cm. The spike actuator is mounted on a cylindrical sleeve, which represents a dynamic mixing device, the spikes having a clearance of 1.5 mm from the walls of the cylindrical sleeve.

A small portion of the effluent from the dynamic mixing device is fed to the recirculation area (see U.S. Patent Application Serial No. 08 / 716,510, which is enclosed in the appendix). In the recirculation area, this part is discharged by the oil and water phase streams into the dynamic mixing area.

A spiral static mixer is provided below the dynamic mixer, which transmits back pressure to the dynamic mixer and allows better incorporation of the component components into the later formed HEPE emulsion. The static mixer is equipped with 12 beers with an outside diameter of 2.5 cm. Below the static mixer is a tube for draining the emulsion to the device used for curing. Optionally, an additional static mixer may be used to provide additional back pressure to fill the tube.

The combined mixer and recirculation system is filled with oil and water phases in a 1: 4 ratio. The dynamic mixer is equipped with a fan that allows air to escape when the unit is full. Flow rates during filling are for the oil phase

7.57 g / sec and for the water phase 30.3 cm ³ / sec.

After the assembly is filled, the dynamic mixer is started, the impeller is rotating at a speed of 850 rpm, recirculation is initiated with an average volume of 30 cm ³ / sec. The water phase flow diameter is then evenly increased up to 151.3 cm ³ / sec over a period of about 1 min, the oil phase flow diameter is reduced to 2.52 weeks for 3 min. Recirculation is gradually increased to a diameter of about 150 cm ³ / sec. The back pressure created by the dynamic region and the static mixers at this time is about 33.8 kPa, which represents a complete pressure drop of the system. The pump operation in the recirculation area is then evenly reduced to a flow rate of approximately 75 cm ³ / sec.

9

9 • * 9 9

9 99

99

9 9 9

9 9 9

9 9 9

9 9 9

99

The HIPE emulsion that flows from the static mixer is currently removed to a 102 cm diameter and 31.8 cm high polyethylene tube with side walls removed. A rigid tubular polyethylene liner with a diameter of 31.8 cm and a height of 31.8 cm is fixed to the center of its base. The HIPE emulsion tubes are then stored for 18 hours in a 65 ° C room where the polymerization of the foam is complete.

After this time, the cured HIPE foam is removed from the curing tubes. The foam now contains the residual aqueous phase (including dissolved emulsifying agents, electrolyte, and initiator residues), which is 55-65 times the weight of polymerized cli monomers. The foam is then cut into slices of 5.1 mm thickness, which are then subjected to compression by a series of two perforating vacuum rollers which gradually de-foam the residual water phase up to three times the weight of polymerized monomers. At this point, the wafers are rewetted with a 4% CaCl 3 solution at 60 ° C and then repressed by a series of three perforating vacuum rollers with a residual water phase loss to twice the weight of the polymerized monomers. _CaCl2 content of the foam is between 2 and 10%.

After the last compression, the foam remains compressed to a thickness of about 0.069 cm and then air dried for 16 hours. This drying reduces the moisture content to about 9-17% by weight of the polymerized mass. The foam slices are very ductile at the moment.

Sample 2

Anhydrous calcium chloride (36.32 kg) and potassium persulfate (189 g) are dissolved in 378 liters of water. This is the source of the water phase that will be continuously fed when the HIPE is formed.

Kmonomer combination (distilled divinylbenzene (42.4% divinylbenzene and 57.6% ethylstyrene) 2.640 g, 2-ethylhexyl acrylate 4.400 g, hexanediol diacrylate 960 g) is added diglycerol monooleate emulsifying agent (640 g), barium (ditallow) dimethyammonium methylsulfate Tinuvin 765 (20g). The diglycerol monooleate emulsifier (Grindsted Products, Brabrand, Denmark) contains approximately 81% diglycerol monooleate, 1% other diglycerol monoesters, 3% polyols and 15% other polyglycerol esters) is a source of a minimum interfacial tension of approximately 2.7 dynes / cm and is critical an oil and water agglomeration concentration of about 2.8 vvt ° o. After mixing, this combination of substances is allowed to settle for a few hours. No visible residue was formed and the entire volume of the mixture was used as the oil phase during the manufacture of the HIPE emulsion.

The separated oil phase (25 ° C) and water phase (75-77 ° C) streams are fed to a dynamic mixing device. Careful mixing of the two streams in the dynamic mixing is accomplished by means of a spike actuator in the form of a cylindrical shaft about 36.5 cm long with a radius of about 2.9 cm. On the shaft there are 6 rows of spikes, 3 rows of 33 spikes and 3 rows of 34 spikes, each level with 3 spikes, forming an angle of 120 ° to each other. 60 degrees. Each spike has a diameter of 0.5 cm and extends outward from the central axis of the shaft to a distance of 2.3 cm. The spike actuator is mounted on a cylindrical sleeve, which represents a dynamic mixing device, the spikes having a clearance of 1.5 mm from the walls of the cylindrical sleeve.

A small portion of the effluent from the dynamic mixing device is fed to the recirculation area (see U.S. Patent Application Publication No. 08 / 716,510, which is appended in the appendix). In the recirculation area, this part is discharged by the oil and water phase streams into the dynamic mixing area.

»9949

9

4 4

4 4 4

4 4 4

4 4 4 •

A spiral static mixer is provided below the dynamic mixer, which transmits back pressure to the dynamic mixer and allows the component components to be better incorporated into the later formed HIPE emulsion. The static mixer is usually equipped with 12 elements with an outer diameter of 3.8 cm, but 17.8 cm has been removed to fit the mixer into the appropriate space. Below the static mixer is a tube for draining the emulsion to the device used for curing. Optionally, an additional static mixer may be used to provide additional back pressure to fill the tube.

The combined mixer and recirculation system is filled with the oil and water phases in a 1: 4 ratio. The dynamic mixer is equipped with a fan that allows air to escape when the unit is full. Flow rates during filling are for the oil phase

7.57 g / sec and for the water phase 30.3 cm ³ / sec.

After the assembly is filled, the dynamic mixer is started, the impeller is rotating at 800 rpm, recirculation is started with an average volume of 30 cm ³ / sec. The flow diameter of the water phase is then increased uniformly up to a diameter of 151.3 cm ³ / sec for about 1 minute, the oil phase flow diameter is reduced to 2.52 g / sec for 3 minutes. Recirculation is gradually increased to a diameter of about 150 cm ³ / sec. The back pressure created by the dynamic region and the static mixers is currently about 29 kPa, which represents a complete pressure drop of the system. The pump operation in the recirculation area is then evenly reduced to a flow rate of approximately 75 cm ³ / sec.

HIPE emulsion that flows from a static mixer. at the moment, it is removed into a polyethylene tube with a diameter of 102 cm and a height of 31.8 cm with removable side walls. A tubular polyethylene liner with a diameter of 31.8 cm and a height of 31.8 cm is fixed to the center of its base. The HIPE emulsion tubes are then stored for 18 hours in a 65 ° C room where the polymerization of the foam is complete.

After this time, the cured HIPE foam is removed from the curing tubes. The foam now contains the residual aqueous phase (including dissolved emulsifiers, electrolyte and initiator residues), which is 58 to 62 times the weight of polymerized monomers. The foam is then cut into slices of 5.1 mm thickness, which are then subjected to compression by a series of two perforating vacuum rollers which gradually de-foam the residual water phase up to six times the weight of the polymerized monomers. At this point, the slices are rewetted with a 1.5% CaCl ₂ solution at 60 ° C and then again subjected to compression by a series of three perforating vacuum cylinders with a loss of residual water phase to twice the weight of polymerized monomers. _CaCl2 content of the foam is between 3-6%.

After the last compression, the foam remains compressed to a thickness of about 0.071 cm ( ⁷ inches) and is then air dried for 16 hours. This drying reduces the moisture content to about 9-17% by weight of the polymerized mass. The foam slices are very ductile at the moment.

Sample 3

Anhydrous calcium chloride (36.32 kg) and potassium persulfate (189 g) are dissolved in 378 L of water. This is the source of the water phase that will be continuously fed when the HIPE is formed.

Kmonomer combination (distilled divinylbenzene (42.4% divinylbenzene and 57.6% ethylstyrene) 2.640 g, 2-ethylhexyl acrylate 4.400 g, hexanedioidiacrylate 960 g) is added diglycerol monooleate emulsifying agent (640 g), barium (ditallow) dimethyammonium methylsulfate Tinuvin 765 (20g). Diglycerol monooleate emulsifying

99 ···· • · * ♦ · • Φ • · · • «· • • ♦ Φ · • ·· * • · * • • • · • · • · »·« » • • • · ♦ 9

-26 The reagent (Grindsted Products, Brabrand, Denmark) contains approximately 81% diglycerol monooleate, 1% other diglycerol monoesters, 3% polyols and 15% other polyglycerol esters) is a source of a minimum interfacial tension of approximately 2.7 dynes / cm and is characterized by a critical concentration oil and water agglomeration of about 2.8 wt ° o. After mixing, this combination of substances is allowed to settle for a few hours. No visible residue was formed and the entire volume of the mixture was used as the oil phase during the manufacture of the HIPE emulsion.

The separated oil phase (25 ° C) and water phase (75-77 ° C) streams are fed to a dynamic mixing device. Thorough mixing of the two streams in the dynamic mixing is accomplished by means of a spike actuator in the form of a cylindrical shaft about 21.6 cm long with a radius of about 1.9 cm. There are 6 rows of spikes on the shaft, one level with 3 rows of 21 spikes, another level also with 3 rows of 21 spikes, the spikes of all levels make an angle of 120 ° to each other, with each additional level offset 0.03 mm and its spikes with tips of adjacent levels angle of 60 °. Each spike has a diameter of 0.5 cm and extends outward from the central axis of the shaft to a distance of 1.4 cm. The spike actuator is mounted on a cylindrical sleeve, which is a dynamic mixing device, the tips having a clearance of 3 mm from the walls of the cylindrical sleeve.

A small portion of the effluent from the dynamic mixing device is fed to the recirculation area (see U.S. Patent Application Serial No. 08 / 716,510, which is enclosed in the appendix). In the recirculation area, this part is discharged by the oil and water phase streams into the dynamic mixing area.

A spiral static mixer is mounted below the dynamic mixer, which transmits back pressure to the dynamic mixer and allows the component components to be better incorporated into the later formed HIPE emulsion. The static mixer is adjusted by a shortening of 6.1 cm. The original length is 35.6 cm long with an outer radius of 1.3 cm.

The combined mixer and recirculation system is filled with oil and water phases in a 1: 4 ratio. The dynamic mixer is equipped with a fan that allows air to escape when the unit is full. Flow rates during filling are 1.89 g / sec for oil phase and 7.56 cm ³ / sec for water phase.

After the assembly is filled, the dynamic mixer is started, the impeller rotates at 1,000 rpm, recirculation is initiated with an average volume of 8 cm ³ / sec. The water phase flow diameter is then evenly increased up to a diameter of 45.4 cm ³ / sec for about 1 min, the oil phase flow diameter is reduced to 6 g / sec for 3 min. Recirculation is gradually increased to a diameter of about 45 cm ³ / sec. The back pressure generated by the dynamic region and the static mixers at this point is about 20 kPa, which represents a complete pressure drop of the system. The pump operation in the recirculation area is then evenly reduced to a flow rate of approximately 75 cm ³ / sec.

The HIPE emulsion that flows from the static mixer is currently taken into a 43 cm diameter and 10 cm high polyethylene tube with removable side walls. To the center of its base is a firmly seated tubular polyethylene liner with a diameter of 12 cm and height

17.1 cm. The HIPE emulsion tubes are then stored for 18 hours in a 65 ° C room where the polymerization of the foam is complete.

After this time, the cured HIPE foam is removed from the curing tubes. The foam now contains the residual aqueous phase (including dissolved emulsifying agents, electrolyte, and initiator residues), which is 70-80 times the weight of polymerized monomers. The foam is then cut into slices of 4.7 mm thickness, which are then subjected to compression by a series of two perforating vacuum rollers which gradually de-foam the residual water phase up to six times the weight of the polymerized monomers. At this time, e 4 4 ·· 4 • 4

4 ·· * «« 4

4 4

4 «4

4 · 4 44 • 4 * 4 · 4 4

4 4 4 • 4 4

The plates were rewetted with a 1.5% CaCl ₂ solution at 60 ° C and then subjected to compression again by a series of three perforating vacuum rollers with a residual water phase loss to twice the weight of the polymerized monomers. _CaCl2 content of the foam is between 3 and 5%.

After the last compression, the foam remains compressed to a thickness of about 0.079 cm and then air dried for 16 hours. This drying reduces the moisture content to about 9-17% by weight of the polymerized mass. The foam slices are very ductile at the moment.

Tests

Unless otherwise specified, the tests are performed under laboratory conditions at a temperature of about 23 ± 2 ° C and a relative humidity of 50 ± 10%. Test samples are stored under these conditions for at least 24 hours before starting the tests. It should be noted that in those cases where the test substances do not comply with the test protocol by their flowability, these substances may be deposited on a hydrophobic cloth which does not affect their absorbency.

Synthetic urea composition

Unless otherwise indicated, the synthetic urea used for these assays is known as Jayco SynUrine and is available from Jayco Pharmaceuticals Company of Camp HI11, Pennsylvania. Contains 2 g / l KC1, gl 2: Na ₂ SO _4, 0.85 gl (NHT) H ₂ PO ₄ 0.15 g / l (NH ₄₎ H ₂ PO _4, 0.19 gl CaCl ₂ and 0.23 g of MgCl ₂ . All of these chemicals are reagent. The pH of synthetic urea is in the range of 6.0-6.4.

Vertical suction speed and vertical suction capacity

The vertical suction rate is determined by the length of time during which a colored test fluid (e.g., synthetic urea) is sucked from the beaker into a test strip of foam of a certain size up to a vertical distance of 15 cm. The vertical suction procedure is detailed in the Tests section of U.S. Patent No. 5,387,207 supra, which is included in the appendix, but is performed at 31 ° C instead of at 37 ° C. The vertical suction capacity at a certain height is measured by the Vertical Suction Absorption Capacity Test, also described in Tests of U.S. Patent No. 5,387,207, but conducted at 31 ° C instead of at 37 ° C. We also omit the washing and re-drying step mentioned in said patent. The value of the vertical suction capacity is given as the equilibrium value at a height of 15 cm. The result is expressed in units of g ^z cm ² / sec.

Vertical suction test

For the purposes of the present invention, it has been found that a preferred method of detecting vertical suction properties may be a Vertical Suction Progress Test which better characterizes the ability of the absorbent (moisture wicking or moisture acquisition / distribution) to absorb moisture vertically. Any mass that is sufficiently cohesive to be can be tested in this way

-28vertically suspended. If the fabric is not sufficiently cohesive, an additional mechanical backing layer may be used to be added to one or both surfaces of the fabric. The additional mechanical backing layer should be in the form of a low base weight fabric or netting that has no or negligible effect on the suction process.

In short, this test is performed by hanging the 20 cm sample strip (at least 27.5 cm overall) vertically in a beaker of test fluid, with the remaining

7.5 cm samples are placed horizontally on a plastic surface. The suction time is measured by electrical sensors. The amount of aspirated fluid per unit of time is measured as the weight loss of the fluid in the beaker. At the end, the sample attempts to be cut into pieces to determine the longitudinal saturation profile.

Thus, the vertical suction test provides the following information:

the amount of aspirated fluid (expressed in g or g per unit of sample or in g per unit of sample);

height of aspirated fluid per unit of time; sample flow per unit time; longitudinal saturation profile of the sample;

The test is carried out using the following equipment (see Figure 7):

The auto-slide holder (950) is set at a height of 20 cm from the level of the test fluid in the beaker (960). The automatically movable holder (950) ensures, by means of a zero-point sensor, that the sample (910) remains in a certain position relative to the level of the test fluid in the beaker (960), i. that it will touch the test fluid level all the time. The auto-slide holder (950) is further equipped with 9 moisture detection rollers (930) at a height of 2, 3.5, 5, 7.5, 10, 12.5, 15, 17.5 and 20 cm above the liquid level in the beaker (962). λ ⁷ two other sensors (930) are located in the horizontal part of the holder. Although the exact width of the rollers (930) is not decisive for the performance of the test, a width of about 0.77 cm is appropriate in our opinion, the diameter of the rollers is about 9.5 mm. Make sure that the centers of the rollers (930) are at the indicated heights. The 2, 5, 10, 15 and 20 cm rollers are attached to the arm (940) in the form of a ladder rung, the rollers at 3.5, 7.5, 12.5 and

17.5 cm are fastened in a similar manner to the second arm (940). In the course of the test, both arms (940) are placed on the opposite surface of the test substance (910), thereby also allowing testing of substances of different thicknesses. Both arms (940) are in a parallel position during the test and slightly inclined (about 5 °) to the vertical.

The test fluid reservoir (960) may be a glass beaker of a capacity such that the level does not drop too much (the beaker may be round, eg, a 150 mra radius and a wall height of 75 mm). To reduce evaporation, cover the beaker with a lid with a slot (approximately 2.5 x 5 cm). A beaker (960) is placed on a scale (965).

In order to carry out the experiment at a constant temperature of 31 ° C and a relative humidity of 85% (unless otherwise specified), the entire apparatus can be placed in an environmental chamber.

Weight changes (965), signals from the rollers (930), and height of the auto-slide bracket (950) are recorded as a function of time by the computer (980). Data can be processed by a variety of programs.

A pair of scissors, a ruler, and an analytical balance are required to determine the weight of the sample parts.

The synthetic urea used in this test is identical in composition to the above description.

-29Test Procedure

The test sample (910) is stored overnight under standard conditions (temperature 22.2 ° C, relative humidity 50%) and the environmental chamber is set at 31 ° C and relative temperature 85%, balancing takes about 45 minutes.

The sample (910) measuring 5 x 27.5 cm is cut using a cut-out die of the same dimensions, the sample is divided by fine dots along its edges into 11 pieces of 2.5 cm each. The sample is pre-weighed and its thickness is measured at a pressure of 620 Pa using a standard caliper scale.

Place the sample (910) between the rollers (930) so that the bottom of the sample is approximately 1 mm below the zero point of the tester, at this time the sample is not immersed in the test fluid. The upper end of the sample (910) is attached to the plastic plate by a conventional adhesive tape (970).

The environmental chamber is closed and the internal environment is equilibrated to the set temperature and relative humidity, reaching the equilibrium state for about 20 minutes.

Data processing is started by inserting the relevant data into the program, ie. eg, sample name, test run length, sample length, width, thickness, temperature, relative humidity. The test is initiated by immersing the sample through an automatically slide holder in the test fluid. I) the amount of aspirated fluid per unit of time is measured and ii) the time at which the aspirated fluid reaches certain heights is continuously recorded.

At the end of the test, the sample (910) is automatically picked up from the container (960). The saturation profile is then measured, taking care that the sample is in the same vertical position as during the test. When dividing the sample into parts, care should be taken not to move the trapped fluid. The sample is removed from the holder and cut vertically into 2.5 cm pieces that are placed in pre-weighed pans. Striped samples must be cut from bottom to top.

Thereafter, the horizontal portion of the sample is cut into a 2.5 cm piece, which is placed in pre-weighed trays. Thereafter, portions of the sample are weighed immediately to minimize evaporation losses. After weighing, portions of the sample are dried and reweighed to determine the dry weight.

Calculations

Amount of aspirated fluid

Possible units:

Q ^{; g} ,

Q *: g / cm ~ of the original dry area

Q: g'g of the original total weight of the sample

Qc ': o vaporized quantity corrected amount of aspirated fluid in g / cm ²

It is necessary to monitor the amount of evaporated liquid from the partially covered beaker (at 31 ° C and 85% relative humidity) - eg 0.009 g / min. In long-term tests, the volume of evaporated water from the wet part of the sample (ie over a test duration of more than 2 hours) should be considered.

The amount of aspirated fluid, corrected for evaporative loss (g / min), can be calculated by subtracting the increasing evaporation volume (ie evaporation from the beaker (g / min)).

-30 times the time (min.), Subtracted from the weight of the fluid in the beaker (g) and divided by the width and thickness (both in cm).

The following quantities are calculated for data collection at certain times:

Increasing amount of aspirated fluid Fi (g / cm ² / min)

Fi = Qi * / ie, where Qj * is the amount of aspirated fluid (g / cm ² ) and h is the time (min.)

Urea flow rate DF; (g / cm ² / min) □Fi ⁼ (Qi * -Qi-1) / (ti-ti.i)

Longitudinal saturation profile of the sample:

Fluid weight gain in each part (g / g) = (weight _in ^ _έηι - weight _{in wet} ^) / weight _in wet state

Taking the weight _{in the} light state ⁼ weight of the wet part (g) weight _{in suc} hé _m = weight of the dry part (g)

In the following, the data entered into the program is described in more detail: the suction test program is used to determine the ratio of fluid increment versus time in determining the properties of the absorbent and / or diaper materials. The program takes data in regular time intervals from the balance equipped with RS-232 output, the length of time intervals is controlled by a computer. The program is compiled for IBM PC and is compatible with DOS 3.0 or any later system.

In the test itself, data (fluid increment and time) and values in all input fields are written to a folder in the current DOS directory. This folder is accessible for further data analysis when processing the results.

The following is a typical test protocol:

Input field

Description of matter

Identification of matter

Sample # 1

Operator: Fluid type: Jayco synthetic urea

Width: 5 cm Temperature: 31.1 ° C

Test duration: 60 minutes

Length: 27.5 cm Weight: 1.9 g

Relative humidity: 85% • · · ·

-31 Output

Time (min) Weight (g) Increment (g'cm ² ) Increment (g''g) Height (cm) 0 0.424011 0.77093 0.223164 2 0.04485 0,924011 1,68002 0.486322 3.5 0,0778167 1,22 2,21818 0.642106 5 0.247167 2,017 3.66727 1.06158 7.5 0.552 2.86401 5,2073 1,50738 10 1.12688 3,79501 6,90002 1.99738 12.5 1.87295 4,5 8,18182 2,36842 15 Dec 3,32845 5,409 9.83454 2.84684 17.5 5,53095 6.25302 11.3691 3.29106 20 May

Test results

Each sample should be subjected to at least two tests. Of course, individual parameters can be reconciled and written accordingly.

A cumulative fluid increment of 15 cm has been found to be particularly suitable for the purposes of the present invention.

Simplified permeability test

With a simplified permeability test, permeability can be measured in two special cases. Either we measure the permeability of a number of porous masses (such as non-woven synthetic fibers or pulp) at 100% saturation, or we measure the permeability of masses that achieve different saturation rates by relative thickness change without being filled with air (e.g. (compressible polymer foams whose permeability can be easily measured at different thicknesses and at different saturation rates).

Especially in the context of polymeric foams, we have found it convenient to carry out these tests at a higher temperature (31 ° C), which better corresponds to the conditions of the absorbent articles when worn.

This test is based on Darcy's law according to which the volume diameter of the liquid through the porous mass corresponds proportionally to the pressure gradient (with a proportional permeability constant).

Q / A = (k / µ) * (DP / L)

Whereas

Q = volume diameter of fluid penetration (cm ³ / s)

A = cross-sectional area (cm ² ) k = permeability (cm ² ) (where 1 Darcy corresponds to 9.869 * 10 ^'13 m ² ) μ = viscosity (Pa * s) □ P / L = pressure gradient (Pa / m)

L = sample thickness (cm)

Thus, the permeability can be calculated at a fixed or given cross-sectional area and viscosity of the test fluid by measuring the pressure drop and changing the volume diameter of the fluid by the sample;

k = (Q / A) * (L / DP) * μ

The test can be performed in two versions. The first relates to the transparency of the permeability (ie the liquid penetrates the sample exclusively in the thickness direction). The second embodiment relates to surface permeability (the liquid penetrates the sample in the x-v direction).

An accessory of the simplified permeability test is shown in Figure 1, wherein a substantially circular or cylindrical sample receiving chamber (120) having an upper (121) and a lower (122) portion is shown. The distance of both of these parts can be measured and adjusted using three circumferentially mounted thickness gauges (145) and adjustment screws (140). It also includes several fluid reservoirs (150, 154, 156) including height adjustment of the water inlet (170) of the reservoir inlet (150), a tube (180), easy-release closures (189) to connect the chamber to other equipment and valves (182). 184, 186, 188). The pressure difference transducer (197) is connected by a tube (180) to the upper pressure detection point (194) and the lower pressure detection point (196). The valve control computer (190) is further connected to a pressure difference transducer (197), a temperature probe (192), and a weight calibration chamber (198).

A circular-shaped specimen (110) of about 2.54 cm diameter is placed between two porous grids (135) in the form of two cylindrical bodies (121, 122) with an inner diameter of 2.54 cm in the specimen storage chamber (120), which is resilient the inlet connection pipes (132) connected to the inlet of the container (150) and the outlet connection (133) to the outlet container (154). The sealed sealing foam (115) prevents fluid leakage around the edges of the sample. The test sample (110) is then compressed to a thickness corresponding to the desired wet compression set (unless otherwise specified) to about 1.4 kPa. Thereafter, fluid is allowed to flow through the sample until a uniform flow is achieved. At the time of uniform flow, the average volume flow and pressure drop as a function of the length of time are recorded using the sample storage chamber (198) and the pressure difference transducer (197). The test can be carried out at any height of the pressure water column up to 80 cm (approx. 7.8 kPa), the height of the water column can be adjusted to the height setting (170). From the collected data it is possible to determine the average volume of fluid flow through the sample at a different pressure.

This device is commercially available as Permeameter from Porous Materials, Inc., Ithaca, New York, USA under the name PMI Liquid Permeameter, which is designated 2/97 in the respective user manual. The device includes two stainless steel porous grids (135) and other components described. Compressed air supply (at least 4.1 bar) is also required to control the operation of the respective valves.

The test fluid is deionized water.

The test is performed in the following steps:

1) Preparation of test sample (s):

In the preparatory test, we decide if one or more layers of the test sample are needed, and the test, as shown below, is carried out at the lowest and highest pressure. We then assemble a number of layers that can maintain a flow rate of between 0.5 cm ³ / sec at the lowest pressure drop and 15 cm7see at the highest pressure drop. The sample flow rate would be

at the same pressure drop should be less than the flow rate through the sample-free device. Conversely, flow should be reduced by using multiple layers of the sample.

Sample size: cut the samples using a circle punch with a diameter of about 2.54 cm. If the specimens are not strong enough, or if they are not sufficiently cohesive to withstand handling, a conventional low base weight support (grid or mesh) may be used.

We cut at least two samples (where necessary, each harvest consists of the necessary number of layers). One of them is saturated with doinized water at the temperature at which the test is to be carried out (31 ° C - unless stated otherwise).

Using a standard gauge, measure the thickness of the wet sample (if necessary after the stabilization period - 30 sec), set at the desired pressure at which the test is to be carried out. The thickness gauge (supplied by AMES, Waltham, MASS, USA) has a pressure base diameter of about 2.86 cm and, unless otherwise specified, exerts a pressure of about 1.4 kPa on the sample.

We choose a seal with a suitable combination of substances, so that the total foam thickness of the seal (115) is 150-200% of the wet sample thickness (taking into account that combined seals of different thicknesses may need to be used to achieve the total required thickness). A 7.62 cm diameter ring is cut from the sealant (115) into which a 2.54 cm diameter bore is cut through the punch.

If the sample size changes after wetting, it is necessary to cut the sample so that it has the desired diameter in the wet state. It is also possible to register a possible change of dimensions in this preliminary test. These changes may cause the sample to leak or wrinkle, both resulting in improper placement on the grid. This means that the sample size needs to be adjusted accordingly.

Insert the test sample (110) into the opening in the sealant foam (115) and place both on the bottom of the bottom half of the sample chamber (120). Check that the position of the sample on the grid (135) is correct and that there are no gaps on the sides of the sample.

Place the upper portion (121) of the sample chamber (120) in a horizontal position and reset all three calibers of thickness (145).

We then place the upper portion (121) of the sample chamber (120) on the lower portion (122) so that the sealing foam (115) with the test sample (110) lies between the two parts. Tighten both parts tightly with the adjustment screws (140) so that all three caliber calipers are set to the same value as measured for a wet sample at the appropriate pressure as described above.

2) Test preparation is started by running the computer program (190) and removing sample identification data and other input data (appropriate pressure, etc.).

3) The test will be performed on one sample (110) over several pressure cycles, with the first value being the lowest pressure. The results of the individual cycles will be stored separately in separate files of the computing unit (190) from where they are drawn to perform the calculations described below.

4) The fluid reservoir inlet (150) is set to the desired height of the water column and a test is initiated by the calculation unit.

5) Insert the sample chamber (120) into the permeameter unit.

6) Open the valves (184, 186, 188) to fill the chamber (120). During this step it is necessary to get rid of the air bubble system. This is achieved by inverting the sample chamber vertically.

9 9

-347) After carefully removing air bubbles, close the bottom fill valves (184, 186) and open the top fill valve (182) to fill the top of the chamber.

8) Fill the fluid reservoir up to the fill line (152).

Thereafter, the flow of the test fluid through the sample is initiated in cooperation with the calculation unit (190). The test can be started after reaching the desired temperature in the sample storage chamber (120).

Upon initiation of the test by the computing unit (120), the fluid outlet is automatically diverted from the waste container (156) to the outlet container (154). Then the temperature and pressure drop data are collected over a period of several minutes.

Upon completion of the test, the computing unit (120) provides the recorded results in numerical or graphical form.

If necessary, the same test sample can be used to measure permeability using a different pressure head followed by a gradual increase in pressure.

The equipment should be cleaned every two weeks and calibrated at least once a week.

The pressure difference is recorded by a pressure difference transducer associated with pressure detection points (194, 196) at the top and bottom of the sample storage chamber. Each test must be preceded by a pre-measurement as other causes of fluid flow resistance may occur in addition to the recorded pressure. Preliminary measurements should be made every day at pressure column heights of 10, 20, 30, 40, 50, 60 70 and 80 cm.

For each pressure value of the test sample, the flow rate should be recorded as Preliminary Corrected Pressure by the calculation unit (120) and this result should be further used to correct the Actual Pressure values of the recorded pressure differences at all pressure column heights. This corrected pressure value is the differential pressure (DP) that should be used in the permeability equation (below).

The permeability can be calculated for each desired pressure value and averaged from all the calculations thus obtained to determine the average permeability of the absorbent mass tested.

Each sample should be subjected to three tests at all pressure column heights, the results should be averaged and the standard deviation calculated. However, it is also possible to measure the permeability at all pressure column heights for one sample and repeat the second and third repetitions on a new sample.

The permeability measurement can be carried out under the same conditions as the permeability transplants measurement, with the modification of the apparatus described above in Figures 2A and 2B, with a partially exploded schematic view of the sample storage chamber. Corresponding parts are designated by equivalent reference numerals, such that, for example, the sample receiving chamber has a mark (220) in the drawing 2, i.e., a " 100 more than the chamber (120) in the drawing of Figure 1, etc. The simplified sample storage chamber (220) is adapted so that fluid can flow in only one direction (depending on how the sample is stored in the chamber). Care should be taken to prevent fluid from penetrating along the walls, as this may result in an erroneous end result. The test procedure is completely analogous to the simplified transplanar test.

The specimen storage chamber (220) is adapted to be inserted into the device in the same manner as the transplant test chamber (120) except that the filling tube is directed to the inlet connection (232) at the bottom of the chamber (220). Figure 2A is a partially exploded view of the sample chamber, and Figure 2B is a cross-sectional view of the chamber at the same level.

The test chamber (220) is made in two parts: a lower portion (225) in the form of a rectangular cassette provided with flanges and an upper portion (223) that fits into the lower portion (225) and is also provided with flanges. The test sample is cut into a square (approximately 5.1 x 5.1 cm) and inserted into the bottom of the chamber (225). The upper part (223) of the chamber is then inserted into the lower part (225) so that it sits on the test sample (210). The upper part (223) is provided with an incompressible neoprene seal (224). The test fluid is routed from the inlet reservoir to the sample space and by connecting the inlet (232) further through the outlet connection (233) to the outlet reservoir. Since in this test the thermal control of the fluid passing through the sample may be insufficient due to the lower flow rate, the temperature of the sample is maintained at the desired level by the heating device (226) (the heating chamber (227) is pushed by the pump. The gap in the sample chamber is set to the sample thickness corresponding to the desired wet compression (usually about 1.4 kPa). Spacers (216) with a gauge of 0.1 mm to 20 mm are used to set the correct gap dimension in the sample chamber, optionally using a combination of several spacers.

At the beginning of the test, the sample chamber (220) is rotated 90 ° (the sample is thus in a vertical position) and the test fluid is allowed to slowly enter from below. Make sure that all air is removed from the sample and from the inlet / outlet connections (232, 233). Then rotate the sample chamber (220) to its original position so that the sample (210) is in the horizontal position. The further procedure corresponds to the procedure described above for the permeability test. Place the inlet reservoir at the desired height, allow equilibrium flow, and measure the average flow and pressure drop. Permeability calculations are performed according to Darcy's law. This procedure is repeated even at higher pressures.

For samples with very low permeability, it may be necessary to increase the rupture pressure (eg by increasing the water column level or by additionally applying atmospheric pressure to the reservoir to achieve a measurable flow diameter).

General fluid permeability test

With the general permeability test, the permeability can be measured as a function of the saturation of any porous mass. The principle of the test is similar to that of the Simplified Test, with the main difference being that, in addition to being filled with liquid, the sample is filled with a certain amount of air, resulting in a given saturation rate. This is accomplished by the test apparatus shown schematically in Figure 3, showing the principles and specific aspects of the general transparency of transmittance, and Figure 4, showing the differences of the apparatus for performing the general surface permeability test. The reference numerals (even those not mentioned in the description) correspond to the corresponding reference numerals in Figure 1 - eg the waste container (356) corresponds to the waste container (156), etc.

The sample chamber (320/420) is fixedly attached to the height adjusting device (372), in addition, the height of the inlet container is adjustable by the height adjusting means (370). The inlet reservoir defines, relative to the outlet reservoir (354), the first height difference (357) which relates to the pressure difference Dp (for the throughput calculation). This inlet reservoir (350) defines a second height difference (359) relative to the sample height, which relates to the pressure difference Dp (c) (associated with the sample saturation rate, with higher capillary suction usually associated with lower saturation).

»· · · · ·

• · · ·

-36 The test starts at a low DPc (close to 0 cm water level) when the sample has 100% saturation. The fluid flows through the sample due to the applied pressure drop np (c) (input tray height - output tray height). In equilibrium, the amount of fluid added to the outlet reservoir is measured as a function of time. Throughput can be measured from pressure drop and volumetric flow projection data using Darcy's law. The exact saturation rate can be calculated from the ratio of the wet sample weight after the test to the dry sample weight before the test.

In order to measure the saturation throughput of less than 100%, a new test sample must be brought to a 100% saturation state, as described above. The sample is then lifted to a higher height (eg 10 cm) and allowed to equilibrate. The fluid flows continuously from the inlet to the outlet reservoir. The saturation rate of the sample will increase over time. After reaching a steady state, the average flow rate, pressure drop and saturation are measured as above. The whole procedure is repeated using new samples at several heights.

In order to obtain a measurable flow diameter, it may be necessary to increase the pressure drop between the inlet and outlet reservoirs as the saturation rate increases. This is because, for most porous masses, permeability decreases sharply as the saturation decreases. It must be ensured that the pressure drop between the inlet and outlet reservoirs is much smaller than the capillary suction.

It is necessary to ensure that the fluid level in the reservoirs does not change significantly during the alignment, and it is therefore necessary to use wide fluid reservoirs (352, 354).

The test shows the permeability value in relation to the saturation during the desorption cycle, i.e.. starting with a higher saturation value of the sample. The permeability values can of course also be derived for the absorption cycle, but these should not be used for calculations of this type, as some hysteresis phenomena could occur.

Sample receiving chamber (320) for general test of transplantation permeability of the sample chamber (120) of the simplified permeability test transplants differs fundamentally ⁷ in that it is equipped with two fntami (335) positioned above and below the sample (310). It must be ensured that the frits have a negligible resistance and that the bulk of the resistance is due to the sample. The fine-pored thin membrane frit allows measurements up to considerable heights without causing significant flow resistance. The frits should be selected so as to have a sufficiently high bubbling pressure point corresponding to a water column more than 200 cm high, but at the same time producing a low flow resistance. This can be easily achieved by depositing selected sufficiently thin membranes with the desired bubbling pressure point over a thinner support grid.

In the general permeability test, care should be taken to allow air to access the side surfaces of the sample so as to allow different degrees of saturation depending on Qp (c). Thus, the embodiment of the sample chamber is identical to the simplified permeability test tube test chamber except that the sealing foam is removed and the means for sealing the gap between the upper and lower portions is replaced by a pressure-producing device such as a weight (317) it loads ( together with the weight of the upper portion (321), the sample at a desired pressure of about 1.4 kPa (unless otherwise specified).

The sample storage chamber (420) in the General Area Permeability Test (see Figure 4) is derived from the Simplified Area Permeability Test Chamber and the above rules. Thus, fluid is introduced into the sample chamber (420) by the fluid inlet (432) and the outlet (433). which are connected to membranes (435) of the type such as the frits (335) described above. The test sample (410) is positioned so that its ends overlap both frits, but not

-37 with its central part (approximately 5.1 x 5.1 cm) to prevent creasing of the specimen and gaps between the specimen and membranes. Place the test sample (410) between the top and bottom of the sample storage chamber (420), using the weights (417) to generate operating pressure (about 1.4 kPa - unless otherwise specified). Also in this case, the sample is kept at a constant temperature by means of a heating device (426) (eg by injecting constant temperature water through the heating chamber (427)).

Again, air access to the sample through its side surfaces is required to allow different degrees of saturation.

Fluid viscosity

Fluid viscosity is an important input parameter for all of the above procedures and should be determined for a given fluid and temperature at either a table, by calculation, or measured by known procedures.

Capillary sorption

The purpose of this test is to measure the capillary sorption absorption capacity as a function of height in the absorbent compositions of the present invention. (The test is also used to measure the capillary sorption absorption capacity as a function of the height of high surface area masses - i.e., without an osmotic absorbent such as a hydrogel-forming absorbent polymer or other optional masses used in the absorbent composition. sorption in relation to the whole moisture-absorbing element). Capillary sorption is an essential property of all absorbents that determines how liquids are absorbed by absorbent materials. In this test, the absorption capacity of the capillary sorption is measured as a function of the liquid pressure caused by the height of the sample relative to the test fluid reservoir.

The essence of the test

The porous glass frit is connected through a continuous column of liquid to the liquid reservoir in equilibrium. The sample is subjected to a constant load during the test. By absorbing the liquid through the porous structure, the equilibrium in the container is disturbed, and the weight loss is recorded as the amount of liquid absorbed (with respect to the amount absorbed by the lip as a function of height and with respect to evaporation). The capillary suction (capillary suction and / or height) of capillary suction is measured. The absorption is increased by decreasing the frit growth (ie by reducing the capillary suction).

Time is monitored during the test to calculate the initial mean effective wicking value (g / g ^ hr) at a liquid column height of 200 cm.

- 38-waybill (Directive 91)

ΦΦ φ φ · · · · · · · · φ φ φ φ • • • • • • • φ φ φ φ φ φ φ φ φ φ φ

Reagents

Test liquid: Synthetic urea, substances in distilled water.

prepared by complete dissolution of the following

Chemicals F.W. KC1 74.6 Na ₂ SO ₄ 142 (NH 3) H ₂ PO ₄ 115 (NH 4) ₂ HPO ₄ 132 CaCl ₂ 2H ₂ O 147 MgCl ₂ .6H ₂ O 203

Concentration (g / 1)

2,0

2,0

0.85

0.15

0.25

0.5

General description of the test equipment

The capillary sorption test equipment (generally designated 520 in Figure 5A) is intended to operate at a temperature of 25 ° C and a relative humidity of 50%. The test sample is placed in a glass frit 502 which is connected through a continuous column of test liquid (synthetic urea) to a balanced liquid reservoir 506 containing the test liquid. The fluid reservoir 506 is placed on a scale 507 connected to a computer (not shown). The scale should be capable of a resolution of 0.001 g. A glass frit 502 is placed on a xertical slide 501 that allows the sample to be moved vertically and thus exposed to varying suction heights. The slide may be a contactless propulsion device connected to a computer to record suction heights and the appropriate time to measure the amount of fluid received by the sample. The measurement results from the propulsion device 501 and the balance 507 are immediately processed into the capillary sorption absorption capacity data of each test sample. The computer interface of the drive device 501 may allow vertical movement of the glass fitting 502. For example, the drive device may be instructed to move the glass flap vertically only after reaching equilibrium at each suction height.

The bottom of the glass frit 502 is connected to a tube 503 that connects the frit 503 to a three-position shut-off drain tap 509, the drain tap 509 is connected by the glass tube 504 and shut-off tap 510 to the fluid reservoir 505. and removing air bubbles) A glass tube 511 with a stopcock 510 connects the fluid reservoir 505 with a balanced fluid reservoir 506. The balanced fluid reservoir 506 consists of a lightweight 12 cm diameter glass beaker 506A and a housing 506B. In the housing 506B there is an opening that allows the glass tube 511 to be connected to the fluid in the reservoir 506. The glass tube 511 must not contact the housing 506B as this would disturb the equilibrium and the results could not be used.

The glass frit must be of a diameter such that a cylinder / piston device (described below) can accommodate the test sample. The glass frit 502 is provided with a jacket to maintain a constant temperature by means of a heated bath. Frit 502 is a 350 ml fritted filter divider with a pore size of 4-5.5 μηι. The poles are fine enough to allow wetting of the frit surface at the prescribed capillary suction heights (the glass frit does not allow air to enter a continuous column of test fluid below the frit).

-39correction sheet (Directive 91) • * *. ·· ♦. «» ♦ ♦ ♦ směrnice směrnice směrnice směrnice směrnice směrnice směrnice směrnice směrnice směrnice směrnice směrnice směrnice směrnice. ♦ · ♦ ♦ »» »» »»

As already mentioned, the 502 is connected by a tube according to the setting of the three-position shut-off valve 510 to the fluid reservoir 505 or to the balanced fluid reservoir 506.

The glass frit is provided with a jacket to receive water from a bath heated to a constant temperature. During the test, the temperature of the frit is thus constantly maintained at 31 ° C. It is apparent from Figure 5A that the glass strand 502 is provided with an inlet port SO2A and an outlet port 502B which forms a closed circuit with a circulating thermal bath 508. (Figure 5A does not show the frit jacket. Water supplied from the bath 508 to the glass frit 502 plastic equipment, comes into contact with the test fluid nor the test liquid is not circulated through this bath. \ ^r ODA of the bath with a constant temperature jacket walls of the glass frit 502.)

The container 506 and the balance 507 are in an enclosed space to minimize evaporation of the test fluid during the test and to maintain the balance of the balance. This space is in the form of a cassette 512 with a top portion and walls, the top portion having an opening through which the tube 511 extends.

The glass frit is shown in more detail in FIG. 5B, which is a cross-section through the frit without an inlet 502A and an outlet 502B port. As already mentioned, it is a sintered filter divider with a pore size of 4-5 µm. The glass frit 502 consists of a cylindrical funnel 550 with a sheath and a glass frit plate 560. Another component is a cylinder / piston assembly 565 (cylinder 566 and piston 568) into which test sample 570 is placed and which exerts little pressure on the sample. Excess evaporation of the test fluid from the glass frit plate 560 is prevented by the Teflon ring 562 placed on the plate. This Teflon ring 562 has a thickness of 0.0127 cm, covering the surface of the frit plate outside the periphery of the cylinder 566, thus minimizing evaporation from the glass frit. Ring inner diameter 562 ie 6.3 cm, outer diameter 7.6 cm. The inner diameter of the ring 562 is approximately 2 mm smaller than the outer diameter of the cylinder 566. A ring 564 is inserted onto the upper surface of the Teflon ring 562 to seal the space between the inner wall of the cylindrical jacket having funnel 550 and the Teflon ring 562.

As already mentioned, the cylinder / piston assembly 565 (see more detail in Figure 5C) closes the test sample and exerts little pressure on it. The assembly 565 consists of a cylinder 566, a cup-shaped Teflon cylinder 568, and (if necessary) a weight (or set of weights) that can be inserted into the Teflon cylinder 568. (Optionally, a weight that is combined with the balance will be used. The cylinder 566 has the following dimensions: outside diameter 7.0 cm, inside diameter 6.0 cm, and height 6.0 cm. The Teflon cylinder 568 has an outer diameter 0.02 cm smaller than the inner diameter of the cylinder 566. It is apparent from Figure 5D that a chamber 590, 1.8 cm deep and a diameter of 5 cm is drilled at the end of the cylinder 568 which does not touch the test sample. 0 cm, into which optional weights are inserted (based on the actual dry sample diameter). These weights together with the weight of the cylinder 568 are to exert a pressure of 1.4 kPa on the test sample. In other words, the total weight of the cylinder 568 and any selected weight (not shown), divided by the actual diameter of the test sample (in the dry state), should be such that a 1.4 kPa pressure is applied to the sample. The cylinder 566 and the piston 568 are equilibrated at a temperature of 31 ° C for at least 30 minutes before starting the capillary suction absorption capacity test.

The air-conditioned destabilization around the sample is minimized during the test by a 14 cm x 14 cm perforated film which is not treated with a surfactant and is placed on a glass frit 502.

• ·

- 40 - Corrigendum (Directive 91) fc fcfcfcfc fcfc fcfc fcfc

Sample preparation

The test sample can be obtained by cutting a 5.4 cm diameter ring from the absorbent to absorb moisture. If this element is a component of the absorbent, the other components must be removed before starting the test. Only in those cases where it is not possible to isolate the element from other component parts of the absorbent without compromising its structure (eg density and / or physical properties, etc.) or when the beer is not a component of the absorbent, is the test sample prepared by combining of all beers, so that the resulting combination represents the element. The test sample takes the form of a ring with a diameter of 5.4 cm and is cut out using a punch.

The dry weight of the test sample (used below to calculate the capillary sorption absorption capacity) is the weight of the sample in a conventional environment prepared as described above.

Preparation of the test equipment

1. Place a clean dry glass frit 502 in a cylindrical funnel 550 attached to the vertical chute 501. Slide the funnel holder of the vertical chute so that the glass frit is 0 cm high.

2. Adjust the device components as described above, as shown in Figure 5A.

3. Place the fluid container 506 with a diameter of 12 cm onto the scale 507. Place the plastic lid 506B on the balanced fluid container 506 and the cartridge lid on the scale cassette 512. Both of these lids are provided with a small opening for extending the glass tube 511. The tube 511 must not touch the lid 506B of the balanced fluid reservoir, as this would disturb the equilibrium and the measurement result could not be used.

4. Adjust the stopcock 510 so that the tube 504 is closed and the tube 511 is opened. The fluid reservoir 505, previously filled with the test fluid, is opened so that the test fluid flows into the tube 511 and fills the balanced fluid reservoir 506.

5. Align the glass frit 502 and grip it firmly in a steady state. Check that the glass frit is dry.

6. Attach the tube 503 to the stopcock 509. (The tube should be long enough to comfortably reach the glass frit 502 at its height of 200 cm.) Fill tube 503 with test fluid from the fluid reservoir 505.

7. Attach the tube 503 to the glass frit 502 in a balanced condition and open the stopcock 509 and the stopcock 510 that leads from the fluid reservoir 505 to the glass frit 502. (Stopcock 510 closes the glass tube 511.) The glass frit 502 in the balanced state is filled with non-sticking liquid, while all trapped air is forced out of the frit. Continue filling until the level of test fluid exceeds the top surface of the glass frit plate 560. Empty the funnel and remove any air bubbles in the tube and inside the funnel. The air bubbles can be removed by inverting the glass frit 502, allowing air bubbles to rise and escape through the tap outlet 509. (Air bubbles usually accumulate at the bottom of the glass frit plate 560.) Re-level the frit at a sufficiently small level to fit into the frit cylindrical funnels with sheath 550 and glass sintered glass surface 560.

Fc fcfc fcfcfc fcfc fcfc fc fc fc fc fc fc fc fc

-41 8. Using a balanced fluid reservoir 506, zero the glass frit. To do this, fill the tube of sufficient length with test fluid. Insert one end into the balanced fluid reservoir 506 and the other end to the height of the glass frit 502. The test fluid level in the tube (which is equivalent to the level in the balanced fluid reservoir) is 10 mm below the top of the glass frit plate 560. replenish either the amount of fluid in the reservoir or reset the vertical slide 501 to zero.

9. Attach the inlet and outlet ports from the thermal bath 508 with tubes to the inlet 502A and outlet port 502B of the glass frit. Allow the glass frit plate 560 to heat to 31 ° C. The temperature can be measured by partially filling the glass frit with test fluid and monitoring the temperature after reaching equilibrium. The bath temperature will have to be slightly higher than 31 ° C to allow some heat loss when the bath fluid flows into the glass frit.

10. The glass frit is equilibrated for 30 minutes.

Capillary sorption parameters

The computer program that determines how long the glass frit remains at each height will be described below.

The capillary sorption is processed by a computer program so that the test sample is at a height above the fluid reservoir. As already mentioned, the fluid reservoir is placed on the scale so that the computer can always take readings from the balance at the end of a given time interval and calculate the average flow (increment / value) between the test sample and the reservoir. For the purpose of this method, the test sample is in a steady state if the flow rate is less than the specified average flow rate in a series of consecutive time intervals. It has been found that for some substances a true equilibrium state may not be achieved if a certain "equilibrium constant" has been reached. The time interval between measurements is 5 seconds.

The number of measurements is shown in the capillary sorption system as “equilibrium patterns” in the increment table. The maximum number of measurements is 500. The flow average in the capillary sorption system is referred to as the "equilibrium constant".

The equilibrium constant units are g / sec ranging from 0.0001 to 100.000.

The following is a simplified flowchart example.

Equilibrium Patterns = 3 Equilibrium Constant = .0015 fc · fcfc ··· ·················· · · · · · ··· • · ······· fc ······ ··· ·· ··

-42When living fluid

0.350

0.300

0.250

0.200

0.150

0.100

0.050

0,000

Time interval

Time interval Load Increasing fluid 0 (G) 0 (g / sec) 1 0,090 0.0180 2 0.165 0.0150 3 0.225 0.0120 4 0.270 0.0090 5 0.295 0.0050 6 0.305 0.0020 7 0.312 0,0014 8 0.316 0.0008 9 0.318 0.0004

· To to to to to to to • to toto toto toto toto toto toto toto toto toto

-43Increment table

Time 0 1 2 3 4 5 6 7 8 9 Delta 1 9999 0.0180 0.0180 0.0180 0.0090 0.0090 0,0090 0,0014 0,0014 0,0014 Delta 2 9999 9999 0.0150 0.0150 0.0150 0.0050 0,0050 0,0050 0.0008 0.0008 Delta 3 9999 9999 9999 0.0120 0.0120 0.0120 0,0020 0,0020 0.0020 0.0004

The equilibrium sorption value in the simplified example is 0.318 g.

Capillary sorption parameters

Load: 1.4 kPa Equilibrium patterns (n): 50 Equilibrium constant: 0.0005 g / sec Adjustment height value: 100 cm Final height value: 0 cm

Hydrostatic pressure parameters: 200, 180, 160, 140, 120, 100, 90, 80, 70, 60, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5 and 0 cm.

The capillary sorption absorption capacity is measured using all of the above heights. Even if we need to determine the absorption capacity of the capillary sorption at a certain height (eg 35 cm), it is necessary to carry out the whole procedure with all the hydrostatic pressure heights in that order. Although all of these heights are used in the capillary sorption test to derive capillary sorption isotherms, the present disclosure deals with absorbent elements to retain fluid in terms of their absorption properties at heights of 200, 140, 100, 50, 35 and 0 cm.

Capillary Sorption Test Procedure

1) Preparation of the device is performed as described above.

2) Make sure that the thermal bath 508 is operating, that the water is circulating through the glass frit 502 and that the temperature of the glass frit plate 560 is 31 ° C.

3) Place the glass frit 502 at a suction height of 200 cm. Open the stopcocks 509 and 510 to connect the glass frit 502 to the balanced fluid reservoir 506. (Due to the fluid reservoir 505, the stopcock 510 is closed.) The glass frit 502 is equilibrated for 30 minutes.

4) Insert the above capillary sorption parameters into the computer.

5) Close taps 509 and 510.

6) Move the glass frit 502 to a height of 100 cm.

7) Place the Teflon ring 562 on the surface of the '560 fritted glass plate. Place the 566 ring on the Teflon ring 562. If necessary, insert additional weights into the piston chamber 590.

»4444

4 • 4 4 »4 44» 4 4

-44 Cover the glass frit 502 with a perforated membrane.

8) The value given by the weight at this time is zero (balanced).

9) Move the glass frit 502 to a height of 200 cm.

10) Open the stopcocks 509 and 510 (with respect to the fluid reservoir 505 the stopcock 510 is closed) and start weighing and reading the time.

Correction of glass frit (comparative sorption)

Since the glass frit plate 560 has a porous structure, it is necessary to determine the value of the capillary sorption (comparative sorption) of the glass frit and subtract it to obtain the true capillary sorption value of the test sample. Glass frit correction is performed for each new frit. The procedure for obtaining the comparative sorption value (g) is the same as above but without using the test sample. The time elapsed at each specific altitude is the time of comparative sorption (s).

Evaporative loss correction

1) Move the glass frit 502 to a height of 2 cm above zero and allow it to equilibrate at this height for 30 minutes with taps 509 and 510 open (closed to the fluid reservoir 505).

2) Close taps 509 and 510.

3) Place the Teflon ring 562 on the surface of the glass frit plate 560. Place the ring 564 on the Teflon ring 562. Place the heated cylinder 566 concentrically on the Teflon ring. Insert the piston 568 into the cylinder 566. Cover the glass frit 502 with a perforated membrane.

4) Open the taps 509 and 510 (closed with respect to the fluid reservoir 505) and record the weight value variations over time for 3.5 hours. Calculate the evaporation loss (g / h) as follows:

(weight deviation in 1 hour - weight deviation in 3.5 hours) / 2.5 hours

Even using the above procedure, there will be some evaporation loss, typically about 0.10 g / hr, both for the test sample and for frit correction.

Laboratory equipment cleaning

Tube 503 is used to reinstall the glass frit 502. If microbial contamination is observed, clean the glass tubes 504 and 511, the fluid reservoir 505 and the balanced fluid reservoir 506 with a 50% Clorox Bleach® solution in distilled water followed by a rinse with distilled water.

and.

Clean laboratory equipment after each use

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-45When each test is completed (after the test sample has been removed), rinse the glass frit from the front (ie the test fluid is flushed to the bottom of the glass frit) with 250 ml of test fluid from the fluid reservoir 505 to remove test sample residues from the glass frit plate pores. With the shut-off taps 509 and 510 open relative to the fluid reservoir 505 and closed relative to the balanced fluid reservoir 506, remove the glass frit from the holder, invert it and rinse first with test fluid and then with additional rinses with acetone and test fluid (synthetic urea). When rinsing, the glass frit is in the inverted position, and the rinsing strikes the surface of the glass frit plate that touches the test sample. Then rinse the glass frit for the second time with 250 ml of test fluid (synthetic urea) from the front. Finally, put the glass frit in the holder again.

b. Monitoring the functionality of the glass frit

The functionality of the glass frit must be monitored after each cleaning and in any case of a newly installed frit. Set the glass frit to a height of 0 cm. Pour 50 ml of test liquid onto the surface of the balanced glass frit plate (without Teflon ring, ring 564 and cylinder / piston assembly). Record the time to increase the test fluid level by 5 ml above the surface of the glass frit plate. If this time exceeds 4.5 minutes, repeated cleaning is required.

c. Repeated cleaning

Glass frits are repeatedly cleaned (see performance monitoring) to remove deposits. The cleaning fluids are distilled water, acetone, 50% Clorox Bleach® solution in distilled water (to remove bacteria) and test fluid. Cleaning involves removing the glass frit from the holder and disconnecting all tubes. Rinse the glass frit from the front (ie pour the cleaning liquid onto the bottom of the frit) with the frits reversed with the appropriate fluids in the appropriate quantity and in the following order:

1. 250 ml distilled water

2. 100 ml acetone

3. 250 ml distilled water

4. 100 ml of Clorox® / distilled water 1: 1

5. 250 ml distilled water

6. 250 ml test fluid

The cleaning result can be considered satisfactory if the functionality of the glass frit is within the above flow criteria and if the surface of the glass frit plate is clean.

Calculations

The result of the computer processing is a report containing capillary sorption height (cm) data, time and weight gain (g) at each specific height. From these data, which includes frit correction and evaporation loss, it is possible to calculate the capillary sorption absorption capacity. On the basis of the capillary sorption absorption capacity at 0 cm, capillary absorption efficiency at specific heights can also be calculated. In addition, an effective weight gain of 200 cm is also calculated.

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-46 Comparative sorption (frit correction) algae Comparative sorption (s) * sample evaporation (g / h)

Correction of comparative increment (g) = comparative increment (g) -------------------------------------- ---- 3600 (s / hour)

Absorption capacity of capillary sorption (AKKS)

Osp = correction of comparative increments

Sample time (s) * sample evaporation (g / h)

Sample weight gain (g) -------------------------------------------- --------- - Osp (g)

3600 s / hour

AKKS (g / g) = ------------------------------------------- -------------------------------------------------- ---- Dry sample weight (g)

Original effective average increment of 200 cm

AKKS at 200 cm (g / g)

PUP (g / g / hr) ----------------------------------------- --- Specific sample time at 200 cm (s)

Reporting of results

At least two tests should be performed on each sample. The average increment at each height should be calculated and the absorption capillary sorption capacity (AKKS) of the absorbent element and / or the corresponding high surface area mass calculated therefrom.

The following values can be calculated from this data:

Desorption height of capillary sorption (DVKS), in which the mass released x% of its capacity at a height of 0 cm (ie AKKS 0, DVKS x), (cm);

Absorption height of capillary sorption (AVKS), in which the mass absorbed y% of its capacity at a height of 0 cm (ie AKKS 0, AVKS y), (cm);

Absorption capacity of capillary sorption at height z (AKKS z) expressed in (g) of fluid / (g) of mass, especially at height 0 cm (AKKS 0) and at height 35 cm, 40 cm etc .;

Absorption efficiency of capillary sorption at height z (ACS z), expressed in%, representing the ratio AKKS 0 to AKKS z.

In the case of a combination of two substances (eg the first substance has the function of a fluid suction / distribution substance and the second has a fluid entrapment function), the AKKS value (and hence the corresponding ACS value) of the second substance can be determined by the DVKS value of the first substance.

-47Test of tea bag capacity in centrifuge (KSO test)

Although the KSO test was developed specifically for superabsorbent materials, it can also be used for other absorbent materials.

This test measures the tea bag capacity values in a centrifuge, which are a measure of the fluid retention capacity of absorbent materials.

Place the absorbent mass in a 'Tea Bag', dip it in a 0.9% sodium chloride solution for 20 minutes and then centrifuge for 3 minutes. The absorption capacity of the absorbent is determined by the ratio of the weight of the retained fluid to the original weight of the dry substance.

Pour two liters of 9% by weight sodium chloride solution in distilled water into a 24 x 30 x 5 cm bowl. The solution should be at a height of about 3 cm from the bottom.

The tea bag is 6.5 x 6.5 cm and is available from Teekanne in Dusseldorf, Germany. The bag is closed with a conventional heat seal.

Open the bag by careful partial incision and weigh. Place about 0.2 g of the absorbent sample, accurately weighed to ± 0.005 g, into it. Then seal the bag with a heat seal. This will prepare the sample bag. We also close the empty tea bag and use it for a comparison experiment.

Place the sample bag and the empty bag on the surface of the saline solution and immerse them for 5 seconds using a copist, allowing complete wetting (the bags will remain on the surface of the saline solution but will be completely soaked). Turn on the timer immediately.

After 20 minutes, remove both bags from the saline solution and place them in a centrifuge with a diameter of 230 mm so that each bag rests on the inner peripheral wall of the centrifuge. Close and start the centrifuge so that the speed of rotation quickly rises to 1,400 rpm. Once the rotation speed has stabilized, start the timer. Stop the centrifuge after 3 minutes.

Remove both bags and weigh separately.

Calculate the capacity of a tea bag in a centrifuge (KSO) with a sample of absorbent mass as follows.

KSO = [(weight of sample bag after centrifugation) - (weight of empty bag after centrifugation) (weight of absorbent in dry state)] - (weight of absorbent in dry state)

In this way, the absorption capacity of other parts of the absorbent means can also be measured in the form of " partial cuts " either parts of the individual elements or parts of the entire absorbent means, wherein the cut is made over the entire thickness of the absorbent means along predetermined points of the longitudinal axis of the means. In particular, the crotch lot as defined above makes it possible to measure the "absorption capacity of the crotch lot". Other slits can be used to determine the "base capacity" (i.e., the value of the capacity of a unit of area - preferably 2 x 2 cm - specific portions of the absorbent).

Final capacity of captured fluid

A number of methods have been proposed to determine or evaluate the ultimate capacity of the entrapped fluid of the absorbent article.

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In the context of the present invention, it is believed that the final capacity of the absorbent composition is the sum of the final absorbent capacities of the individual elements or substances. A variety of established procedures can be used to calculate the capacities of individual components, provided they are used systematically throughout the measurement. For example, the tea bag capacity test in the centrifuge (KSO test), which was developed and undertaken in the measurement of superabsorbent polymers (SAP), can be used in addition to SAP materials to measure the capacity of other substances.

Knowing the capacities of the individual substances, the capacity of the entire absorbent article can be calculated by multiplying the resulting values (in ml / g) of these substances by the weight contained in the absorbent article.

In the case of substances having a function other than the ultimate fluid acquisition - for example, suction layers and others, the ultimate absorption capacity may be neglected as these substances actually have a very low capacity or are intended to be to another function and therefore releases fluids to other substances.

Calculation of density, basis weight and thickness measurement

We shall weigh the sample cut with the sample punch to an accuracy of at least 0,1%. When measuring thickness, a pressure of 550 Pa is applied to the 50 mm sample area. The basis weight is the weight of the sample per unit area in g / m ² , the thickness is expressed in mm under a pressure of 550 Pa and the density is expressed in g / m ³ . These values can be calculated very easily.

Claims (45)

PATENT CLAIMS 1. Moisture distributors with improved distribution properties at lower humidification rates, including a moisture distribution element with a capillary sorption desorption height value at 50% capacity drop at 0 cm (DVKS 50), with a permeability to (100) at 100% saturation and permeability k (50) at 50% saturation, this moisture distribution element is characterized by a DVKS 50 value of less than about 150 cm, a permeability at 100% saturation to (100) of more than about 1 Darcy, and a permeability at 50% saturation k (50) represents more than about 14% transmittance at 100% saturation. The moisture distribution element of claim 1, having a transmittance at 100% saturation to (100) of more than about 2 Darcy. The moisture distribution element of claim 1 having a transmittance at 100% saturation to (100) of greater than about 8 Darcy. denotes value denotes value The moisture distribution element of claim 1, which is characterized by a transmittance at 100% saturation to (100) of greater than about 8 Darcy. value The moisture distribution element of any one of claims 1-4, characterized in that its transmittance at 50% saturation k (50) represents more than about 18% transmittance at 100% saturation k (100). The moisture distribution element of claim 5, wherein its moisture permeability at 50% saturation k (50) is greater than about 25% permeability at 100% saturation k (100). The moisture distribution element of claim 6, wherein its transmittance at 50% saturation k (50) is greater than about 35% transmittance at 100% saturation k (100). The moisture distribution element of any one of claims 1-7, characterized in that its transmittance at 30% saturation k (30) represents more than about 3.5% transmittance at 100% saturation k (100). The moisture distribution element of claim 8, wherein its transmittance at 30% saturation k (30) is greater than about 5% transmittance at 100% saturation k (100). The moisture distribution element of claim 9, wherein its moisture permeability at 30% saturation k (30) is greater than about 10% permeability at 100% saturation k (100). A moisture distribution beer according to any one of claims 1-10, characterized by a desorption height of capillary sorption at a 50% capacity drop (D'VKS 50) of less than about 100 cm. The moisture distribution element of claim 11, characterized by a desorption height of the capillary sorption at a 50% capacity drop (DVKS 50) of less than about 75 cm. The moisture distribution element according to claim 12, characterized by a desorption height of the capillary sorption at a 50% capacity drop (DVKS 50) of less than about 50 cm. 14. A moisture distribution element having a capillary sorption desorption height value at 50% capacity drop (DVKS 50), a 100% saturation throughput at 100% saturation and a 50% saturation throughput at 50%, characterized in that the DVKS value is 50 is less than about 150 cm, 100% saturation throughput k (100) is greater than about 1 Darcy, 50% saturation throughput (50) is greater than about 14% throughput at 100% saturation, and 15 cm flow rate is at least 0.045 g / cm ² / sec according to the vertical waveform test described above. The moisture distribution element according to claim 14, characterized by a flow rate of 15 cm at least 0.06 tycm ² / sec ·. A moisture distribution beer as claimed in claim 14, characterized by a flow rate of 15 cm at least 0.1 g / cm ² / sec. The moisture distribution element of claim 14, wherein the moisture permeability at 100% saturation k (100) is greater than 2 Darcy. The moisture distribution element of claim 14, wherein the moisture permeability at 100% saturation k (100) is greater than about 8 Darcy. The moisture distribution element of claim 14, wherein the moisture transfer rate at 100% saturation k (100) is greater than about 8 Darcy. The moisture distribution element of any one of claims 14-19, characterized in that its transmittance at 50% saturation k (50) represents more than about 18% transmittance at 100% saturation k (100). The moisture distribution beer of claim 20, wherein its moisture permeability at 50% saturation k (50) is greater than about 25% permeability at 100% saturation k (100). The moisture distribution element of claim 20, wherein its transmittance at 50% saturation k (50) is greater than about 35% transmittance at 100% saturation k (100). β · · · - 51 A moisture distribution beer according to any one of claims 14-22, characterized in that its transmittance at 30% saturation k (30) represents more than about 3.5% transmittance at 100% saturation k (100). The moisture distribution beer of claim 23, wherein its moisture permeability at 30% saturation k (30) is greater than about 5% permeability at 100% saturation k (100). The moisture distribution element of claim 23, wherein its moisture permeability at 30% saturation k (30) is greater than about 10% permeability at 100% saturation k (100). The moisture distribution element of any one of claims 14-25, characterized by a desorption height of the capillary sorption at a 50% capacity drop (DVKS 50) of less than about 100 cm. A moisture distribution element according to any one of claims 14-26, characterized by a desorption height of capillary sorption at a 50% capacity drop (DVKS 50) of less than about 75 cm. A moisture distribution element according to any one of claims 14-27, characterized by a desorption height of the capillary sorption at a 50% capacity drop (DVKS 50) of less than about 50 cm. The moisture distribution element of any preceding claim, further comprising a hydrophilic flexible polymeric foam having interconnected open cells. The moisture distribution element according to claim 29, further characterized in that it is increased in volume by wetting. 31. The moisture distribution element of claim 29, further characterized in that its volume is reduced after dehumidification. A moisture distribution element according to any one of claims 29-31, characterized by a capillary breakdown pressure of at least about 15 cm. The moisture distribution element of any one of claims 29-32, characterized by a free absorbent capacity of at least about 15 g / g. An absorbent means comprising a moisture distribution element according to any one of the preceding claims, further comprising a first moisture collection area that withdraws moisture from the moisture distribution element. The absorbent article of claim 34, further comprising at least a second moisture trapping region and wherein both moisture trapping regions take up moisture from the moisture distribution element. 5236. The absorbent article of any one of claims 34 or 35, wherein at least one of the two moisture acquisition areas comprises a 50% capillary sorption (AVKS 50) absorbent height substance of at least about 40 cm. 37. The absorbent article of Claim 34, further comprising a fluid acquisition device having a fluid storage capacity of about 80% of the total absorbent core capacity. 38. The absorbent article of Claim 34, further comprising a fluid acquisition device having a capacity of about 90% of the total capacity of the absorbent core to hold the fluid. 39. An absorbent article comprising an absorbent core comprising a crotch portion and one or more waist portions, characterized in that the crotch portion has less fluid acquisition capacity than one or more portions of the waist together, and the crotch portion is a moisture distribution element according to any one of claims 1-33. The absorbent article of Claim 39, wherein the final base capacity to retain fluid in the crotch portion is less than 0.9 times the final base capacity to retain fluid in the absorbent core. 41. The absorbent article of claim 40, characterized in that said final basic capacity to entrap fluid crotch region is smaller than a multiple of the final basic 0,5t ⁷ capture capacity of the fluid absorbent core. 42. The absorbent article of claim 41, wherein the final fluid storage capacity of the crotch portion is less than a multiple of 0.3 (i.e., 0.3x) the final fluid storage capacity of the absorbent core. 43. The absorbent article of Claim 39, wherein the local final fluid storage capacity of the crotch portion is less than 49% of the final fluid storage capacity of the entire absorbent core. 44. The absorbent article of claim 39, wherein the local final fluid storage capacity of the crotch portion is less than 41% of the final fluid storage capacity of the entire absorbent core. 45. The absorbent article of claim 39, wherein the local final fluid storage capacity of the crotch portion is less than 23% of the final fluid storage capacity of the entire absorbent core. 46. An absorbent article according to any one of claims 39-45, further characterized in that at least 50% of the area of the crotch portion does not refer to the concept of ultimate fluid storage capacity. -5347. The absorbent article of any one of claims 39-46, further characterized in that less than 50% of the final fluid acquisition capacity is in the front half of the absorbent article in front of the crotch portion and more than 50% of the final fluid acquisition capacity is in the back half of the absorbent means. 48. The absorbent article of claim 47, wherein less than 33% of the final fluid acquisition capacity is in the front half of the absorbent article in front of the crotch portion and more than 67% of the final fluid acquisition capacity is in the back half of the absorbent article.