RU2364513C1 - Absorbing composite material and method of its manufacturing - Google Patents

Abstract

FIELD: items of private use.

SUBSTANCE: invention relates to absorbing composite material for absorption of liquids of organism, to method and device of its receiving and product for absorption of organism's liquids including such material. Composite material contains material of basis, corresponding cloth and/or paper and particles of water-absorbing resin with particles size from 100 micrometres up to 2700 micrometres, formation by salts of polyacrylic acid. Method consists in saturation of basis material and/or water-absorbing resin by water with following drying of basis material and water-absorbing resin, at which they are in contact to each other. Device for receiving of absorbing composite material includes feed unit of basis material; rotary drum for implementation of combining of resin particles with basis material; feed unit of resin particles into rotary drum; drying unit for removing of water from basis material and combined with it resin particles; feed unit of determined quantity of moisture into basis material and/or resin particles.

EFFECT: product for absorption of liquids of organism consists of permeable for sheet liquid, impenetrable for sheet liquid and specified absorbing composite material, located between them.

28 cl, 60 ex, 9 tbl, 24 dwg

Description

FIELD OF THE INVENTION

The present invention relates to a thin, light sheet absorber and a method for its production. Due to the fact that the absorber is an absorbing composite material with excellent water absorption, absorption rate and high ability to distribute liquid, it is suitable for use in hygiene products, such as disposable diapers and sanitary napkins. The present invention also relates to an environmentally friendly absorber, allowing to reduce the amount of pulp, water-absorbing resin and similar materials commonly used for the manufacture of hygiene materials.

State of the art

Disposable diapers, sanitary napkins and other hygiene products include an absorber, absorbing body fluids and other fluids, a soft, liquid-permeable top sheet located on the body contacting side, and a liquid-impervious sheet on the back side farthest from the body. The absorber is usually made from a mixture of pulp or other fibrous material and a water-absorbing resin.

In recent years, there has been an increase in demand for thinner, lighter hygienic materials that can solve problems in the areas of design, distribution, recycling, etc. The most commonly used way to meet this demand is to reduce the amount of fiber or other material in the hygienic material that serves as the basis for the water-absorbing resin, and to use more water-absorbing resin. Such hygienic materials with a lower content of hydrophilic fibers and a high content of water-absorbing resin can better accumulate liquid, but not necessarily distribute and disperse it well with the actual use of diapers. That is, when the liquid is absorbed, a large amount of the water-absorbing resin turns into a soft gel, which leads to an effect called gel blocking, which seriously complicates the distribution of the liquid. If gel blocking has occurred, the resin can no longer function properly, while not only does it absorb less water, but this absorption also occurs at a slower rate.

In order to avoid these problems and preserve the absorption properties of the material, one cannot arbitrarily change the ratio of the amounts of hydrophilic fibers and the water-absorbing resin, that is, there are limits to reducing the number of hydrophilic fibers and reducing the thickness of the hygienic material. In addition, since cellulose is most often used as a fibrous material in hygiene products, in particular cellulose from primary raw materials due to its purity, the introduction of large quantities of fibers is associated with increased consumption of forest resources.

The proposed methods for preventing gel blocking that occurs when fewer fibers and more water-absorbing resin are used include a method in which two different water-absorbing resins with different absorption capacity are used (see, for example, Patent Document 1), a method of using a composition consisting of cationic ion exchange forming a hydrogel polymer and anionic ion exchange forming a hydrogel polymer (see, for example, patent document 2), the method of using water an absorption resin with a high crosslink density on the surface (see, for example, Patent Document 3), a method for using a water-absorbing resin whose surface has a lower salt concentration than the entire volume (see, for example, Patent Document 32), and an extrusion method and foaming a mixture of a water-absorbing resin and a thermoplastic resin to form a plate (see, for example, patent document 4). However, the materials obtained by these methods have inherent disadvantages such as high cost and poor absorption properties used in the absorber with a high concentration of water-absorbing resin. In addition, due to the fact that when using these methods, the relative amount of hydrophilic fibers that serve to fix the water-absorbing resin is reduced, the resin particles tend to move during use of the product or are unevenly distributed before use. When the absorbent resin is thus moved from a predetermined position, the product loses its shape, and the excreted urine or other liquid does not come into contact with the water-absorbing resin of the hygiene product, which leads to leaks.

Another way is to mix the fibers and the water-absorbing resin in an exact proportion, which prevents the uneven distribution and blocking of one part of the water-absorbing resin by its other part (see, for example, patent document 5). In this way, a high degree of mixing is achieved, since the water-absorbing resin and the pulp are first mixed in water, and then dry mixed with hydrophilic fibers and shaped into sheets with air. However, the problem is that in the process of forming the web with air, the water-absorbing resin can be knocked down. And when this happens, it is necessary to remove clods from the drum, which reduces the performance of the installation. It is also preferable to use a fairly rigid absorbent resin to prevent clumping and, if this occurs, to facilitate their removal. In general, hard water-absorbing resins are characterized by low absorption capacity, therefore, to absorb a given amount of liquid, a large amount of water-absorbing resin will be required. This method is also unsatisfactory in terms of preventing movement and uneven distribution of water-absorbing resin in the product.

To solve these problems, especially the problems of displacement and uneven distribution of water-absorbing resin, methods for bonding water-absorbing resin to a substrate were investigated. Examples of such methods are embossing of an absorber; the method according to which the absorber, along with the water-absorbing resin and hydrophilic fibers, contains thermoplastic binder fibers, and the array of absorbing material is fused when heated; the method according to which the absorber, along with the water-absorbing resin and hydrophilic fibers, contains a synthetic resin capable of substantially restoring shape after deformation, and the mass of the absorbing material is fused when heated (see, for example, patent documents 6 and 7); a method in which the surface of a water-absorbing resin containing anionic groups is coated with a cationic polymer so that when the resin swells, the particles adhere to each other and thus are fixed (see, for example, patent documents 8 and 9); the method of use for fixing the water-absorbing resin and hydrophilic fibers of an emulsion binder; the method of use for fixing the water-absorbing resin on the base material of hot melt adhesive (see, for example, patent documents 10 and 11), etc. Due to the fact that in the above examples, the particles of the water-absorbing resin are stacked on a substrate on top of each other, so that the proportion of the water-absorbing resin increases, the blocking effect is enhanced, and therefore more binder must be used. When a large amount of a binder is used to fix the water-absorbing resin on the base material in this way, among other things, the bond strength itself can limit the swelling of the water-absorbing resin. In particular, the absorption capacity inherent in a water-absorbing resin may not be fully realized if the water-absorbing resin, hydrophilic fibers, and the like. fixed with a thermoplastic binder or emulsion.

Methods to remove restrictions on the swelling of a water-absorbing resin fixed on a substrate include a water-absorbing composite material containing a water-absorbing resin, part of which is held inside the loose non-woven fabric, while the open surface of the resin is covered with thin cellulose fibers, and the outer surface of the composite material is coated with fibrillated hot-melt adhesive (see for example, patent document 12); and an absorbent composite sheet material containing a water-absorbing resin, part of which is held inside the loose non-woven fabric and part extends to the surface, and the outer surface of the resin is covered with a double layer of hot-melt adhesive in the form of a fiber network, the layers of which have different cell sizes (see, for example, patent document 13). Although thanks to these methods it is possible to reduce the limitations of swelling, fixation still adversely affects the absorbing properties. As already shown, the absorption properties of a water-absorbing resin are characterized not only by absorption capacity, absorption rate, absorption capacity under pressure, the relationship between the ability to distribute liquid and absorption capacity under pressure and the permeability of a swollen gel for a liquid, but also by a capillary absorption coefficient that reflects absorption in the result of the capillary effect in the gaps between the particles (see, for example, patent documents 14 and 15). It has been shown that capillary absorption and other absorption properties of a water-absorbing resin are degraded by conventional fixing methods. That is, even for highly effective water-absorbing resins, the absorption properties of the absorbing array obtained by fixing these resins often do not correspond to the absorption properties inherent in these resins. It is also noted that it is not necessary to pay increased attention to the characteristics of the water-absorbing resin, since they are realized only in a minimal amount (see, for example, patent document 16), and that it is actually difficult to distinguish the difference in the absorption properties of water-absorbing resins when they are part of the absorbent array, making it difficult to distinguish between absorbing arrays.

In some cases, glue is used to bond the absorbing gel to chemically hardened cellulose fibers (see, for example, Patent Document 17). In accordance with this method, chemically hardened cellulose fibers provide a space for swelling of the absorbing gel, effectively separating particles of the water-absorbing resin and facilitating its functioning. However, these fibers are not connected to each other and inevitably move within the absorbent array, causing a corresponding movement of the absorbing gel. In addition, large quantities of cellulose are needed, since in order to provide a space for swelling of the absorbing gel, it must be wrapped with cellulose fibers, and the space for swelling itself is disproportionate. You also need to use a lot of glue, which inevitably is a hindrance to swelling. Bonding can also be achieved using a base material and a crosslinking agent (see, for example, patent document 18). In this way, an absorbent composite material with good liquid permeability was obtained, for which purpose a crosslinking agent was used that does not limit the swelling of the gel, and light particles that did not cause gel blocking. However, since a crosslinking agent is required for bonding, the absorption capacity of the particles may decrease when some of them are crosslinked. In addition, it was noted that with an increase in the degree of crosslinking on the surface, the functioning under load improves, while the effect from the point of view of preventing blocking may be inadequate. In addition, the absorption capacity of this composite material is low due to the low weight of the particles used.

In some cases, the water-absorbing resin is fixed to the base material without the aid of a binder. In accordance with one of the methods, the particles of the absorbing polymer are bonded to the fibrous base material during the polymerization, and the polymerization is carried out on the fibrous base material (see, for example, patent document 19). In this case, the fibrous base material is introduced between the polymer particles, and the particles are rigidly fixed, however, it is difficult to completely carry out the reaction in the base material, therefore, the presence of large amounts of unused monomer and crosslinking agent is likely. In another example, a certain amount, or slightly more, of an aqueous solution of the monomer in the form of fine particles is applied to the pile non-woven fabric and then polymerization and thermal compression are carried out (see, for example, patent document 20). The absorption characteristics of this composite material are high, since a large amount of water-absorbing resin is used, and due to the use of a non-woven fabric, compared to the pulp, the movement is reduced. However, due to the fact that the polymerization is carried out inside the nonwoven fabric, the problem of unreacted monomers is not removed. Another way is to re-impregnate the water-absorbing resin with an aqueous solution of unpolymerized monomer, apply it to the base material and polymerization of the absorbed monomer, as a result of which the water-absorbing resin binds to the base material (see, for example, patent document 31), however, it is difficult to completely complete the polymerization of the monomer after it bonding with the base material, and a large number of monomers remains unused.

In a similar example, a suspension is made from the water-absorbing resin, which is applied to the base material (see, for example, patent document 21). Due to the use of the suspension, productivity undoubtedly increases, however, expensive microfibers must be used as a dispersion medium, and the bond strength may be unsatisfactory. In thin hygienic materials and other absorbent materials, in which the proportion of water-absorbing resin is higher, the use of a larger amount of water-absorbing resin may cause the absorption of moisture, swelling, the resin, depending on how it is placed, will become quite bulky. The stronger the water-absorbing resin is fixed, the more it presses on the body during swelling.

A method has also been proposed for applying droplets of an aqueous solution of low viscosity monomer to a fabric, followed by the polymerization reaction with this fabric, whereby gaps between the polymerized particles are formed and gel blocking is prevented (see, for example, patent document 30). In this case, due to the difficulty of fully polymerizing the base material, large quantities of unreacted monomers and low molecular weight components remain. This not only makes the product unsuitable for use as a hygienic material, but also reduces the absorption rate. When placing resin on both sides of one sheet of fabric in order to obtain the desired absorption level with respect to the area of the particles of this resin, in addition, they should have a large size of 550 μm or more, and with a very small ratio of surface area to volume for spherical, hemispherical and deformed spherical particles obtained by this method, the absorption rate necessary for real use is not provided.

From the point of view of the feeling of comfort when using hygiene products, it is important to prevent not only the likelihood of leakage, but also the appearance of moisture. Absorbent articles have been proposed in which the sensation of moisture is reduced due to the regulation of humidity increasing with their use (see, for example, patent documents 22 and 23). In accordance with the methods described in these publications, the absorbent arrays contain absolutely dry cellulose, a large amount of absorbent polymer with a high absorbency and hygroscopic material, such as silica gel or lithium chloride, in combination with a moisture-permeable sheet placed on the back side. A moisture permeable sheet is also used on the back of some absorbent articles (see, for example, Patent Document 24). According to another method, in order to prevent liquid from seeping through the moisture-permeable back sheet, even a combination of two moisture-permeable sheets is used under pressure. However, due to the fact that in these methods the fluids released by the body between the fibers of the paper or pulp are not fixed, with a large volume of secretions, the non-fixed liquid can form a flow causing an increase in humidity.

Hygienic pads have also been proposed in which rewetting, the source of which is the absorption array, can be avoided by using such an absorption array in which the values of the centrifugal capacity after swelling as a result of equilibrium absorption of artificial blood and the passage rate of artificial blood are equal to or higher than the set value (see ., for example, patent document 25), a multilayer absorbent paper having made from mixed bulk cellulose fibers the host layer, which first comes into contact with the liquid, and one or more layers of the base material, laminated on the surface layer (see, for example, patent document 25), and an absorbent sheet consisting of finely dispersed hydrophilic fibers or finely dispersed hydrophilic powder, absorbing polymer with high absorption capacity and bulk cellulose fibers (see, for example, patent document 27). However, these publications do not describe the structure of the absorbent product, which allows to significantly control the flow and suppress the increase in humidity, even when the volume of discharge (the volume of liquid that must be absorbed) is large.

Another method of controlling moisture for the absorbent layer uses fibers with a low ability to retain water (see, for example, patent document 28). This method undoubtedly allows you to reduce humidity, but due to the fact that these fibers can hardly fulfill the absorption function, it is entirely carried out by an absorbing resin, characterized by a low absorption rate, which slows down the absorption. In addition, since the fibers expand slightly during swelling, the occurrence of gel blocking and the difficulty in the proper functioning of the water-absorbing resin are likely.

It was reported that the absorption capacity of the water-absorbing resin depends on the shape of the particles (see, for example, patent document 29). Widely used particles of water-absorbing resin do not differ in expressed length or fineness and have a diameter of from about 45 to 850 microns and a weighted average diameter of from about 200 to 370 microns, however, the absorption capacity of a certain structure as a whole and the effective capacity of the water-absorbing resin in it can be improved by expanding the particle size distribution with an average particle diameter of 400 to 700 microns. However, usually, if the absorption capacity increases, the gel blocking effect cannot be avoided, since the contact between the particles increases. In addition, the absorption capacity of the absorption array is small due to the small proportion of water-absorbing resin in it.

Thus, in most absorbent arrays in which the water-absorbing resin is bonded to the base material, polymerization of monomers (with the associated problem of unreacted monomers) or glue (limiting swelling) is used for bonding, and a satisfactory bonding method does not exist. In addition, so far only absorbing arrays with low characteristics have been produced, since the state of the resin in them after binding is not adequate to the task of functioning with a high level of absorption. That is, a thin, light absorbing array having high liquid capacity and absorption rate, high liquid distribution ability and array stability has not yet been obtained.

[Patent Document 1] Japanese Patent Laid-Open No. 2001-252307

[Patent Document 2] WO 98/037149

[Patent document 3] Japanese Patent Application Laid-Open No. 06-057010

[Patent Document 4] WO 01/64153

[Patent Document 5] Japanese Patent Laid-Open No. 5-230747

[Patent Document 6] Japanese Patent Application Laid-Open No. 10-118114

[Patent Document 7] Japanese Patent Application Laid-Open No. 10-118115

[Patent Document 8] Japanese Patent Laid-Open No. 5-31362

[Patent Document 9] Japanese Patent Application Laid-Open No. 6-370

[Patent Document 10] Japanese Patent Application Laid-Open No. 2000-238161

[Patent Document 11] Japanese Translation of PCT International Publication No. 10-510447

[Patent Document 12] Japanese Patent Laid-Open No. 2001-96654

[Patent Document 13] Japanese Patent Laid-Open No. 2001-171027

[Patent Document 14] Japanese Patent Application No. 2002-72476

[Patent Document 15] Japanese Patent Application No. 2001-375375

[Patent Document 16] Japanese Patent Application Laid-Open No. 2001-96654

[Patent Document 17] Japanese Patent Application Laid-Open No. 10-512183

[Patent Document 18] Japanese Translation of PCT International Publication No. 10-508528

[Patent document 19] Japanese Patent Application Laid-Open No. 2003-11118

[Patent Document 20] Japanese Patent Laid-Open No. 2004-124303

[Patent Document 21] Japanese Patent Application Laid-Open No. 11-137600

[Patent Document 22] Japanese Patent Application Laid-Open No. 6-218007

[Patent Document 23] Japanese Patent Application Laid-Open No. 7-132126

[Patent Document 24] Japanese Translation of PCT International Publication No. 10-508521

[Patent Document 25] Japanese Patent Application Laid-Open No. 7-184956

[Patent document 26] Japanese Patent Application Laid-Open No. 6-287886

[Patent Document 27] Japanese Patent Application Laid-Open No. 9-156013

[Patent Document 28] Japanese Patent Application Laid-Open No. 2002-165837

[Patent Document 29] Japanese Patent Application No. 2904791

[Patent Document 30] US 2003/0205318 A1

[Patent Document 31] Japanese Patent Application Laid-Open No. 9-239912

[Patent document 32] Japanese Patent Application Laid-Open No. 2005-200630

SUMMARY OF THE INVENTION

Problems to be Solved by the Present Invention

The aim of the present invention is a thin, lightweight absorber and products for the absorption of body fluids with high water absorption capacity, absorption rate and high ability to distribute liquid. In particular, it is an object of the present invention to provide an absorber and article for absorbing body fluids that can have a positive effect when used in disposable diapers, sanitary napkins, incontinence pads, and the like. More specifically, it is an object of the present invention to provide an absorber and an article for absorbing body fluids having stable absorption with virtually no bias or uneven distribution of the absorber in the hygiene article, which can absorb the required amount of liquid with the minimum amount of material used. In addition, it is an object of the present invention to provide an environmentally friendly absorber and article for absorbing body fluids, whereby pulp and other resources commonly used in the manufacture of hygiene products are saved.

Means of solving these problems

As a result of research aimed at solving the above problems, it was found that a high absorption capacity can be achieved with a small amount of water-absorbing resin and a reduced amount of other materials if we use composite absorbent material formed by a base material and particles of a water-absorbing resin, in which the base material and particles of water-absorbing resin are combined in special proportions and placed in a special way.

That is, the invention is an absorbent composite material, a method for manufacturing this absorbent composite material, and a device for producing this absorbent composite material.

An absorbent composite material containing a base material and particles of a water-absorbing resin, for which the following conditions (1) - (4) are met:

(1) the weight ratio of the amount of water-absorbing resin to the total amount of base material and water-absorbing resin is from 65 to 99% by weight.,

(2) the weight of the particles of the water-absorbing resin directly bonded to the base material is 50% by weight. or more of the total particle weight of the water-absorbing resin,

(3) the average absorption capacity of the particles of water-absorbing resin is 50 g / g or more,

(4) the amount of unreacted monomers in the water-absorbing resin is 200 ppm or less.

A method of obtaining an absorbent composite material containing a base material and particles of a water-absorbing resin, which consists in saturating the base material and / or water-absorbing resin with water, followed by removing water and drying the base material and the water-absorbing resin, in which they are in contact with each other.

A device for producing an absorbent composite material containing a base material and particles of a water-absorbing resin, including a base material supply unit; a rotary drum for binding resin particles to a base material; a unit for supplying resin particles to the rotary drum; a drying unit for removing water from the base material and associated resin particles; a unit for supplying a certain amount of moisture to the base material and / or resin particles, which device has the following characteristic features (1) and (2):

(1) the surface of the rotating drum has many holes,

(2) there is a vent at the bottom of each well through which gas can escape from the inside of the rotating drum.

Technical result

The object of the present invention is a single absorbent composite material containing a plurality of particles of water-absorbing resin connected to the base material, as a result of which a thin absorber is provided, characterized by a high ability to distribute liquid and a high capacity for liquid. When using this absorber in the composition of a hygienic material or products for absorbing body fluids, the production of such a hygienic material can be simplified, and since the water-absorbing resin is used efficiently, the amount of water-absorbing resin and paper, fabric and other materials included in the absorbent can be reduced. As a result, it becomes possible to produce very thin, light hygienic materials and other products for absorbing body fluids.

Description of a preferred embodiment of the invention

Further, the present invention is explained in more detail.

1. General description of the structure and functioning of the absorbent composite material

In the context of the present invention, an absorbent composite material means a combination of a water-absorbing resin and a base material. In this composite material, 50% by weight. or more particles of water-absorbing resin is directly related to the base material, thus, the probability of a change in the position of the resin particles is small. Therefore, the base material retains the shape of the plate. The absorption capacity of a given absorbent composite material acting as an absorber is preferably controlled by incorporating cellulosic pulp or other fibers or other sheet materials into the absorbing composite material.

In accordance with the present invention, the particles of the water-absorbing resin preferably have a relatively large size (particle diameter is from 550 microns to 2100 microns) [and hereinafter referred to as "large particles"], since the absorbent composite material with such particles has a high absorption capacity per unit area and absorption rate, which is sufficient to use this material in hygiene products. Usually large particles are avoided in absorbers that are part of hygiene materials due to their low absorption rate, however, if they are directly connected to the fibers of the base material, the liquid can be transported to the particles through the fibers associated with them, stress resulting from of morphological changes in the fibers upon contact with water, is transferred to large particles associated with them, and the absorption rate of these particles is significantly increased, which allows the use of such particles as part of an absorber for the manufacture of hygiene products.

When placing the resin particles on the base material, it is preferable to maintain the area occupancy by large particles on at least one sheet at a level of from 1 to 30%, since during swelling, the resin particles collide with each other, which interferes with their further swelling, as a result of which, if there is not enough space for swelling of particles in a direction parallel to the plane of the base material, the resin in the composition of the composite material will not be able to carry out proper absorption. In this case, it is more preferable to place the particles so that they are not in contact with each other, more preferably, to place particles of the water-absorbing resin at intervals. Particles of water-absorbing resin, preferably placed in a single layer, so that they do not overlap each other. In addition, large particles are preferably arranged on both sides so that the area occupancy by large particles on each side is from 1 to 30%. If the composite material also contains particles of a relatively small size, when swelling they will be located below the large particles, without creating significant difficulties for the swelling of large particles, that is, it is possible and preferable to adjust the absorption rate in accordance with that required for this absorber by adding small particles. When such relatively fine particles are added in order to control the absorption rate, the coefficient of the total surface area (described in detail below) is preferably adjusted to be from 0.3 to 3 so as to provide the necessary balance between the absorption capacity and the absorption rate of the composite material.

Since the hygiene material must have a relatively high absorption capacity, the weight ratio of the amount of water-absorbing resin to the total weight of the water-absorbing resin and the base material should be in the range of 65 to 99% by weight.

The reason that even with such a high weight ratio does not result in gel blocking is because 50% by weight. or more resin particles are bonded to the base material, which guarantees a certain space between the resin particles. The proportion of bound resin particles is preferably at least 60% by weight, more preferably at least 70% by weight, even more preferably at least 90% by weight. and ideally - 95% weight. or more. Preferably, the particles of the water-absorbing resin were associated with the base material, as in this case the movement of particles of the water-absorbing resin during the transportation of products or during the absorption of body fluids is excluded.

The choice of a method for directly bonding particles of a water-absorbing resin to a base material has no particular limitations. Preferably, some fibers of the base material are incorporated into the particles of the water-absorbing resin. Preferably, at least 50% by weight. particles directly related to the base material was associated with the inclusion of certain fibers in them; preferably at least 70%, more preferably at least 90%, and more preferably at least 95% by weight. water-absorbing resin was bound in this way. When particles of a water-absorbing resin are bonded to the base material with the inclusion of certain fibers, these fibers supply body fluids to the resin particles, and the absorption capacity of the particles under pressure, as well as the absorption rate, increase.

It is impossible to achieve a high absorptive capacity of the absorber only by using large particles and, thereby, increasing the volume of the resin relative to the area, the resin particles must also have a high absorption capacity. That is, the average absorption capacity of the water-absorbing resin particles used should be at least 50 g / g. Particles of a water-absorbing resin with such an absorption capacity are usually susceptible to the effect of gel blocking, and their swelling can be seriously hindered by pushing the resin particles against each other, therefore it is impossible to obtain an absorbing composite material that meets various requirements, only by using a composite material with a high proportion of resin constituting more than 50% weight. Therefore, it was previously necessary to use hard resin particles with a high degree of crosslinking on the surface and inside, which have a high absorption capacity under pressure and a low absorption capacity. In accordance with the present invention, the particles of the water-absorbing resin are positioned so as to prevent the gel blocking effect, and due to the presence of channels in the resin in some cases, high absorption capacity under pressure can be achieved even when using soft resin particles with high absorption capacity. As a result, the resulting absorbent composite material has a high absorption capacity both under pressure and without it.

In addition, due to the fact that the absorbent composite material of the present invention has a high ability to distribute liquid and allows maximum absorption of the entire water-absorbing resin, it is not necessary to use an excessive amount of water-absorbing resin, and therefore, the weight of the absorbent composite material can be reduced. To increase the absorption capacity of a given composite material, it is preferable to increase the proportion of a resin with a high absorption capacity and, more preferably, use an absorption resin with a higher absorption capacity.

In accordance with the recommended standards of the Japan Hygiene Manufacturers Association, it is desirable to reduce the amount of unreacted monomers in the water-absorbing resin. One of the distinguishing features of the absorbent composite material that is the subject of the present invention is that the amount of unreacted monomers in the water-absorbing resin is reduced to a very small amount of 200 ppm or less. It is difficult to achieve such a value during the polymerization of the resin on the base material, i.e. by the method widely used for direct binding of the resin to the base material. Such a low level of unreacted monomers can be obtained by pre-polymerizing the water-absorbing resin, followed by using this resin, which is characterized by a particularly low content of unreacted monomers, as the water-absorbing resin in the composite material.

2. Binding

In accordance with the present invention, it is preferable that at the time of using this absorbent composite material, at least 60% by weight, preferably at least 70% by weight, more preferably at least 90% by weight, even more preferably at least 99% by weight. the total number of particles of water-absorbing resin was associated with the base material.

According to the present invention, the position in which the particles of the water-absorbing resin are bonded to the base material means the position in which the particles of the water-absorbing resin are fixed to the base material and the relative position of the base material and the particles of the water-absorbing resin does not change significantly. In particular, bound particles are particles that do not separate from the surface of the absorbent composite material after shaking it for one minute with an intensity of 2 full (forward and backward) shaking per second with an amplitude of 20 cm (20 cm backward and 20 cm forward) at holding the edges of the absorbent composite material with your hands.

If the relative position of the base material and the particles of the water-absorbing resin does not change, the absorption capacity of this absorbent composite material will not change during transportation before use, in addition, this is preferable from the point of view of re-absorption.

The proportion of bound particles can be determined by forcibly separating the bound particles with tweezers or the like and weighing them.

In accordance with the present invention at the time of use of this absorbent composite material, at least 50% by weight. the total amount of water-absorbing particles are directly related to the base material. Preferably, at least 60% by weight, more preferably at least 70% by weight, even more preferably at least 90% by weight. or ideally at least 99% by weight. particles are directly related to the base material.

Direct bonding in the context of this document means that the particles are bonded without using any other components, such as glue, in addition to those components, which include the base material, particles of water-absorbing resin and their derivatives. However, particles are still considered to be directly bonded if the adhesive is used in an amount that does not prevent their swelling.

The proportion of directly bonded particles can be determined by measuring the amount of water-absorbing resin particles that remained bound to the base material after immersing the absorbent composite material for 1 hour in a solvent dissolving the adhesive.

The choice of the direct bonding method does not have certain restrictions, it can be bonding as a result of the formation of a chemical bond between the base material and particles of the water-absorbing resin, bonding as a result of physical interaction and bonding by incorporating the fibers of the base material into the water-absorbing resin.

Of these methods, it is preferable to bind by incorporating fibers of the base material into a water-absorbing resin. Namely, it is preferred that at least 50% by weight. the total number of particles of the water-absorbing resin were associated with the fibers included in the water-absorbing resin. Preferably, at least 60% by weight, more preferably at least 70% by weight, even more preferably at least 90% by weight. particles are bound in this way.

The inclusion of fibers in the water-absorbing resin means that the fibers of the base material are included in the matrix of the water-absorbing resin. There are no specific limitations on the shape and length of the included fibers. Due to the fact that water supplied through the fibers can be absorbed into such a water-absorbing resin, the bonding of this type provides the highest absorption capacity in terms of the volume of absorbed liquid and the absorption rate. An electron microscope can be used to determine whether particle bonding occurs with fibers incorporated into the water-absorbing resin. Their fraction is determined by randomly selecting 30 bound particles, forcibly separating these particles from the base material and examining them under a microscope.

In the context of the present invention, it does not matter how the remaining particles of the water-absorbing resin are bonded, since at least 50% by weight. the total number of particles of water-absorbing resin are directly related to the base material.

However, it is preferable not to use glue, since it is necessary to prevent swelling when absorbing liquid. The use of glue is not preferable, since the glue can interfere with the swelling of the water-absorbing resin. Examples of adhesives include thermoplastic fibers and polymers, emulsion binders, hot melt adhesives, and the like.

The bonded coarse particles are preferably positioned such that the area occupancy by the resin (to be described below) is from 1 to 30%. Realization of the absorption capacity of large particles is facilitated if they are arranged so that they do not come into contact with each other while absorbing the expected amount of liquid. Large particles can be associated with only one side of the base material or can be associated with both sides. Preferably, they are associated with both sides, since in this case the volume of absorbed unit area of the liquid increases.

3. The weight ratio of the absorbent resin

In the context of the present invention, the weight ratio of the water-absorbing resin is set in the form of a weight percent of the water-absorbing resin relative to the total weight of the base material and the water-absorbing resin and is specifically determined by the formula 1:

The weight ratio of resin (% wt.) = A / B × 100 (Formula 1)

(where A (g) is the weight of the water-absorbing resin included in the absorbent composite material and B (g) is the total weight of the base material and the water-absorbing resin).

The specified weight ratio to the time of use of the absorbent composite material should be at least 65% by weight. and not more than 99% by weight, preferably at least 70% by weight. and not more than 99% by weight, or, more preferably, at least 80% by weight. and no more than 99% weight. The higher the indicated weight ratio, the greater the total amount of liquid absorbed by this composite material. The weight of the water-absorbing resin is determined after separation of all particles.

3. Area occupancy with resin

In the context of the present invention, the area occupancy by particles of a water-absorbing resin with a size range from 550 to 2100 μm (i.e., large particles) is an indication of the possibility of contact between the particles after the particles of the absorption resin have absorbed the liquid. In the context of the present invention, the area occupancy by the resin in the form of large particles is measured as follows.

Using an optical or electron microscope, an image of the surface of an absorbing composite material is obtained. The measurement and magnification conditions are chosen so that the particles of the water-absorbing resin are distinguishable from the base material, and that 10 or more particles of the water-absorbing resin with a diameter of 550 to 2100 μm (i.e. large particles) fit in this image. An enlarged photocopy of this image is made, the parts corresponding to the particles of the water-absorbing resin are cut out, separated from the parts corresponding to the base material, and large particles are selected from the parts with the image of the particles of the water-absorbing resin. For this selection, use the following method.

A square sheet of paper is prepared corresponding to a square with a side of 500 μm of the composite material, the size of which is calculated based on the magnification values during image acquisition and photocopy production. A square sheet of paper corresponding to a square with a side of 2500 μm of composite material is prepared in the same way. Large particles are selected by overlapping each part of the image image of the particles of water-absorbing resin on these squares and excluding those particles whose image copies are small and fit inside a square with a side of 500 μm or large and look, even slightly, out of the square with a side of 2500 μm.

Then, the selected cut-off parts corresponding to large particles and the entire enlarged photocopy are weighed and the area occupancy with resin in the form of large particles is calculated according to the formula below 2. This procedure is performed for any five or more points on the surface of the absorbent composite material, and the obtained average value is taken as area occupancy with resin. When particles of water-absorbing resin are bonded to both sides of the base material, the area occupancy by the resin is determined similarly for each side.

Resin occupancy (%) = weight of cut parts corresponding to large particles / weight of the whole enlarged photocopy × 100 (formula 2)

The area filled with resin by the time the absorbent composite material is used is preferably from 1 to 30%, more preferably from 2 to 25%, even more preferably from 3 to 20%. If the area is filled with resin is too large, the particles of the water-absorbing resin during swelling will contact each other, causing a blocking effect, so that the water-absorbing resin will not be able to maximize its absorption capacity. If the area is filled with resin is too small, the amount of absorbed liquid per unit area of the absorbent composite material will be small, which is undesirable.

4. The coefficient of the total surface area

In the context of the present invention, the coefficient of the total surface area reflects the surface area of the particles of the water-absorbing resin per unit area of the absorbent composite material. The higher the coefficient of the total surface area, the higher the absorption rate of the absorbent composite material, therefore, higher values of the coefficient of the total surface area are preferred.

The value of the coefficient of the total surface area at the time of use of the absorbent composite material is preferably from about 0.1 to 3, and when particularly fast absorption is required in the early stages (within the first minute after the start of use), this value is preferably 0.3 to 3, more preferably 0.4 to 3, or even more preferably 0.5 to 3.

In accordance with the present invention, the coefficient of the total surface area is determined by formula 3 by collecting the particles of the water-absorbing resin used in the composition of the specified absorbing composite material, classifying them by size, measuring the weight and bulk density of the particles in the corresponding size range.

(где Wr - общий вес (г) частиц водопоглощающей смолы размера r (см), Cr - объемная плотность (г/см²) частиц водопоглощающей смолы размера r (см), S - площадь (см²) поглощающего композиционного материала).

(where Wr is the total weight (g) of particles of water-absorbing resin of size r (cm), Cr is the bulk density (g / cm ² ) of particles of water-absorbing resin of size r (cm), S is the area (cm ² ) of the absorbing composite material).

Particles of water-absorbing resin are removed (by stripping when they are bonded to the base material) and collected to measure their size and bulk density; if fibers or the like have adhered to the surface of the particles of the water-absorbing resin, they are removed prior to measurement. When fibers are incorporated into particles of a water-absorbing resin, these fibers are cut off from the surface of the particles before starting measurements. When glue or the like is applied to the surface of the particles of the water-absorbing resin, it is removed using a solvent that is not absorbed by the water-absorbing resin.

The particle size of the water-absorbing resin is measured by sieving through sieves with a mesh size of 106 μm, 212 μm, 300 μm, 425 μm, 500 μm, 600 μm, 710 μm, 850 μm, 1000 μm, 1180 μm, 1400 μm, 1700 μm and 2500 microns. In accordance with the present invention, the determined particle size is an intermediate value between the cell size of two screens, through one of which this particle passes, and through the other - does not pass. The size of the particles that pass through the sieve with a mesh size of 106 μm is taken to be 53 μm, and the size of the particles remaining on the sieve with a mesh size of 2500 μm is taken to be 2700 μm. As a result of this operation, the particles are classified by size 53 μm, 159 μm, 256 μm, 362.5 μm, 462.5 μm, 550 μm, 655 μm, 780 μm, 925 μm, 1090 μm, 1290 μm, 1550 μm, 1850 μm, 2100 μm and 2700 μm.

The bulk density of the particles of the water-absorbing resin is determined by measuring 2 cm ^{3 of the} water-absorbing resin using a 2 cm ³ volumetric flask and dividing its weight in half. Bulk density is measured 5 times and an average value is taken. Bulk density is measured for particles of each size after their classification on sieves.

5. Particles of water-absorbing resin

Water-absorbing resin

First, a water-absorbing resin is described that forms particles of a water-absorbing resin.

In accordance with the present invention, the concentration of unreacted monomers in the water-absorbing resin is preferably 200 parts per million or less, more preferably 100 parts per million or less, even more preferably 50 parts per million or less, and even more preferably 10 parts per million or less relative to the weight of the water-absorbing resin. It is not preferable that the water-absorbing resin contains unreacted monomers in high concentration, since they are washed out when the resin absorbs liquid.

The amount of unreacted monomers can be reduced by completing the polymerization by heat treatment during or after the manufacture of the absorbent composite. The concentration of unreacted monomers in the absorbent resin before it comes in contact with the base material is preferably 5% or less, more preferably 1% or less, even more preferably 0.1% or less, and even more preferably 0.05% or less. It is not preferable to use a water-absorbing resin containing a lot of unreacted monomers as starting material, since it is difficult to complete the polymerization during the production of the composite material, and in the end a significant amount of unreacted monomers remains. When using a method involving a polymerization reaction, the texture of the base material may also be damaged.

For these reasons, in accordance with the present invention, it is preferable to use amorphous particles produced by the method of polymerizing an aqueous solution, followed by grinding, and / or particles resulting from suspension polymerization with phase reversal.

The amount of unreacted monomers can be measured in the following way. The water-absorbing resin is introduced into a 0.9% saline solution, the amount of which is 250 times the weight of the resin, unreacted monomers are extracted for 6 hours with stirring at room temperature, then filtered. The amount of unreacted monomers in the filtrate is determined by liquid chromatography.

In accordance with the present invention, the type of water-absorbing resin has no particular restrictions, any water-absorbing resin can be used. Preferred is a water-absorbing resin having acid groups in the side chains, and particularly preferred is a resin having carboxyl groups in the side chains. Preferably, 50% or more of the acid groups are neutralized to form salts, and it is particularly preferred that 50% or more of the acid groups is neutralized to form ammonium salts. A water-absorbing resin with acid groups in the side chains is preferable, since due to the static repulsion of the acid groups during absorption of the liquid, the absorption rate increases. It is desirable that these acid groups be neutralized, because it is possible to absorb the liquid inside the water-absorbing resin under the action of osmotic pressure. Preferably, the acid groups are neutralized to form ammonium salts, since ammonium salts have a high affinity for water and, therefore, have a greater absorption potential.

Many types of water-absorbing resins are known, including crosslinked partially neutralized polyacrylic acid (see, for example, Japanese Patent Laid-open No. S55-84304), hydrolyzed grafted starch and acrylonitrile copolymer (see, for example, Japanese Patent No. S49-43395), neutralized grafted a copolymer of starch and acrylic acid (see, for example, Japanese Patent Laid-open Application No. S51-125468), a saponified vinyl acetate-acrylic ester copolymer (see, for example, Japanese Patent Laid-open No. S52-14689), hydrolyzed acrylonitrile copolymer or acrylamide copolymer (see, for example, Japanese Patent No. S53-15959), polyglutamic acid salts (see, for example, Japanese Patent Laid-open No. 2003-192794) and the like.

Copolymers of salts of polyacrylic acid and crosslinked partially neutralized polyacrylic acid, which are widely used in hygiene materials, are preferred in terms of absorption characteristics and cost.

Further, as an acceptable example of a water-absorbing resin, cross-linked polyacrylic acid and a method for its production are described.

In cross-linked polyacrylic acid, preferably at least 50 mol%, more preferably at least 80 mol%, even more preferably at least 90 mol%. repeating units of the polymer molecule are units containing a carboxyl group. It is undesirable for the proportion of units containing a carboxyl group in the polymer molecule to be 50 mol%. or less, since this adversely affects the absorption capacity.

Preferably, the carboxyl groups included in the polymer molecule are partially neutralized to form alkali metal salts, including sodium, potassium and lithium, and nitrogen-containing basic compounds, including ammonium. Preferably, at least 50% and, more preferably at least 70% of the carboxyl groups are neutralized. From the point of view of the type of salt, it is preferred that the carboxyl groups are partially neutralized to form at least one salt including ammonium, and it is most preferred that the carboxyl groups are partially neutralized only to form an ammonium salt. From the point of view of absorption capacity, it is preferable that at least 50 mol%, more preferably at least 70 mol%, even more preferably at least 90 mol%. and ideally, all carboxyl groups of the polymer molecule, neutralized with the formation of salts, were ammonium salts. From the point of view of absorption capacity and the ability to bind to the base material, it is preferable that the proportion of ammonium salts is large. The proportion of ammonium salts in the water-absorbing resin can be calculated based on the total number of nitrogen atoms in the resin. The total number of nitrogen atoms in the water-absorbing resin can be determined by the Kjeldahl method.

The monomers constituting the water-absorbing resin may be salts of unsaturated carboxylic acids such as methacrylic acid, ethacrylic acid, itaconic acid, maleic acid, crotonic acid, fumaric acid, sorbic acid, cinnamic acid and their anhydrides, preferably methacrylic acid salts are used. When neutralizing the acid, salts are formed, preferably, by alkali metals, including lithium, sodium and potassium, or by nitrogen-containing basic compounds, including ammonium. Copolymerization with other monomers is also possible, and examples of unsaturated monomers suitable for copolymerization include anionic unsaturated monomers such as methacrylic acid, ethacrylic acid, itaconic acid, maleic acid, crotonic acid, sorbic acid, cinnamic acid and their anhydrides, vinyl sulfonic acid allyl sulfonic acid, styrene sulfonic acid, vinyl toluenesulfonic acid, 2-methacrylamide-2-methylpropanesulfonic acid, 2-methacryloethanesulfonic acid, 2-methacryloylp ropansulfonic acid, 2-hydroxyethyl acryloyl phosphate, 2-hydroxyl ethyl methacryloyl phosphate, pentyl 2-acryloyl ethylephosphate, vinyl phosphoric acid and the corresponding salts, unsaturated monomers containing non-ionic hydrophilic groups, such as acrylamide, methacrylamide-n-propylamide, n-acrylamide-amide, , n, n-dimethylmethacrylamide, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, methoxypolyethylene glycol methacrylate, polyethylene glycol monomethacrylate, n-vinyl pyrrolidone, n-acryloyl piperidine and n-a riloilpirrolidin, hydrophilic monomers, possessing the property to absorb water from the hydrolysis of the functional groups after polymerization such as methyl methacrylate, ethyl methacrylate and vinyl acetate. Hydrophobic monomers that can be used in combination include styrene, vinyl chloride, butadiene, isobutene, ethylene, propylene, stearyl methacrylate, lauryl methacrylate and the like, which can be used individually or in combination of two or more monomers.

Together with these monomers, a crosslinking agent can be used, and the resin can be crosslinked as a result of the condensation reaction of the crosslinking agent with the functional groups of the resin; copolymerization of a polymerizable crosslinking agent with unsaturated monomers or as a result of exposure to a resin by an electron beam or radiation, and the like. A preferred crosslinking method is the use of a condensing crosslinking agent, and a more preferred crosslinking method is the copolymerization of a polymerizable crosslinking agent with unsaturated monomers in the presence of a condensing crosslinking agent which reacts with the functional groups of the resin.

Examples of condensing crosslinking agents include glycidyl ether-based compounds such as ethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, polyglycerol polyglycidyl ether, diglycerol polyglycidyl ether and propylene glycol diglycidyl ether; polyvalent alcohols such as polyglycerol, polyethylene glycol, propylene glycol, 1,3-propanediol, polyoxyethylene glycol, triethylene glycol, tetraethylene glycol, diethanolamine and triethanolamine; polyvalent amines such as ethylenediamine, diethylenediamine, polyethyleneimine and hexamethylenediamine; polyvalent ions, such as zinc, calcium, magnesium and aluminum ions; these crosslinking agents can be used in combination of two or more agents.

Examples of polymerizable crosslinking agents that copolymerize with unsaturated monomers include diethylene glycol diacrylate, n, n'-methylene-bis-acrylamide, polyethylene glycol diacrylate, polypropylene glycol diacrylate, trimethyloliprylate trilithryl ether, diphenyl ether triethyl ether, di-acrylate, di-acrylate, di-acrylamide isocyanuric acid diacrylate, a salt of tetraallyloxyethane and diallyloxyacetic acid; these crosslinking agents can be used in combination of two or more agents.

The choice of solvent to obtain a monomer solution has no particular limitations, since these monomers are highly soluble. It is especially desirable to use only water, but hydrophilic solvents such as ethanol, methanol and acetone can also be used, individually or in combination of two or more substances. Also, if necessary, a salt can be added, such as sodium chloride, a compound with basic properties, such as ammonia, pH adjusters, or, in the case of suspension polymerization with phase reversal, a suspending agent.

The choice of the method of polymerization of unsaturated monomers does not have certain restrictions, widely known methods can be used, such as polymerization in aqueous solution, suspension polymerization with phase reversal, emulsion polymerization with phase reversal, polymerization in a stream, tape polymerization, etc. The choice of a method for initiating polymerization is also not limited; polymerization can be initiated using a radical polymerization initiator, exposure to radiation, an electron beam, etc. or, during polymerization in ultraviolet radiation, using a photosensitizer. The initiator used in the radical polymerization may be a known initiator, for example, a persulfate such as potassium persulfate, ammonium persulfate or sodium persulfate; hydrogen peroxide; organic peroxide such as cumene hydroperoxide, tert-butyl hydroperoxide, peracetic acid and the like. When using an oxidizing radical polymerization initiator, a reducing agent such as L-ascorbic acid or rongalite may also be added.

Prior to initiating the polymerization, dissolved oxygen is preferably removed from the monomer solution. This is done, for example, by sparging or another method of treating an inactive gas for a certain time. The atmosphere in the reaction vessel is preferably formed by an inactive gas, such as nitrogen or helium. A rarefaction, normal pressure, or elevated pressure may be created in the reaction vessel. The polymerization initiation temperature is preferably in the range of 0 to 100 ° C., more preferably in the range of 20 to 70 ° C. If the initiation temperature is too high, the polymerization begins as a result of heating until the initiator is added, which is undesirable. A low initiation temperature is also undesirable, since then the initiation reaction takes longer. The temperature in the reaction vessel during the reaction may vary spontaneously, or it can be controlled by cooling or heating. The rate of temperature increase during polymerization and its maximum value can not be precisely controlled, the maximum temperature can exceed 100 ° C. The value of the maximum temperature during the polymerization usually lies in the range from 20 to 140 ° C or, preferably, from 40 to 120 ° C. The concentration of monomer in the solution is preferably from 10 to 80%, more preferably from 30 to 70%. It is undesirable for this concentration to be too large, since then the reaction can get out of control. It is also undesirable for this concentration to be too low, since in this case the reaction will take too much time and difficulties will arise in the subsequent drying step. It is preferable to stop the polymerization when the reaction solution ceases to produce heat. Since the polymerization is followed by processes related to heating, such as drying, crosslinking, etc., the polymerization can also be terminated before the reaction solution ceases to produce heat. This solution, after it ceases to give off heat, can also be heated or kept warm.

The polymer obtained by the described wet gel polymerization is dried. The choice of drying method has no particular limitations. Azeotropic distillation dehydration, fluidized bed drying, hot air drying, vacuum drying and the like can be used, preferably, hot air drying or vacuum drying. The polymer is dried until the water content in it becomes 30% by weight. or less, preferably 10% by weight. or less. The wet gel can be dried in any form, preferably, before drying, increase the surface area of the polymer by coarse grinding. The drying temperature range is preferably from 70 to 180 ° C., more preferably from 100 to 140 ° C.

The particle size of the dried polymer is adjusted to the desired value by grinding or classification. If crosslinked polyacrylic acid is used, the dried polymer can be ground to obtain the desired particle size and then heated. During heat treatment, it is desirable to add a compound having 2 or more functional groups capable of reacting with carboxyl groups. This compound having 2 or more functional groups capable of reacting with carboxyl groups can be introduced before polymerization or added to the particles before heat treatment. If the compound is added before the heat treatment, it is preferable to introduce it by dissolving in a hydrophilic solvent such as water, alcohol or ether, and spray the resulting solution onto the surface. The temperature of the heat treatment is not strictly limited, its value preferably lies in the range from 120 to 250 ° C, more preferably from 150 to 240 ° C, even more preferably from 170 to 230 ° C. Heat treatment can be carried out continuously on the same equipment as drying, or at a stage independent of drying.

For said heat treatment, a conventional dryer or oven may be used, for example a tunnel dryer, a drum dryer, a disk dryer, a fluidized bed dryer, an air flow dryer, a radiation dryer, and the like.

If necessary, deodorants, perfumes, various inorganic powders, blowing agents, pigments, dyes, antibacterial agents, short hydrophilic fibers, plasticizers, adhesives, surfactants, fertilizers, oxidizing agents, reducing agents, chelating agents, antioxidants can be added to the water-absorbing resin. , heat resistance agents, infrared absorbers, light resistance agents, water, salts, and the like.

Examples of these inorganic powders include fine particles of various inorganic compounds that are inactive with water and hydrophilic organic solvents, and fine particles of clay minerals. It is especially desirable to use as inorganic powders those which have a certain affinity for water, but are insoluble or poorly soluble in it, examples thereof include metals, oxides, such as silicon dioxide, titanium; silicic acids (salts), such as natural zeolite, artificial zeolite; kaolin; talc; clay; concrete, etc.

Inorganic powders are typically used in an amount of from 0.001 to 10 parts by weight, or preferably from 0.01 to 5 parts by weight, per 100 parts by weight of a water-absorbing resin. The choice of the method of mixing the water-absorbing resin and inorganic powder does not have certain restrictions, it can be mixing of dry components, wet mixing, etc.

Particle shape

The particles of the water-absorbing resin can be of any shape, are spherical particles widely used in absorbent compositions, amorphous particles, aggregated particles, short fibers or sheet-shaped particles. Amorphous particles obtained by grinding, particle aggregates (for example, in the form of a bunch of grapes), particles in the form of flakes, granules, etc. can also be used. It is preferable to use aggregated particles, spherical particles or amorphous particles.

However, the water-absorbing resin used in the form of large particles is preferably amorphous particles obtained by polymerization of an aqueous solution, followed by grinding, and / or aggregated particles obtained by suspension polymerisation with phase reversal. The reason for this choice is that, using spherical particles, it is difficult to obtain a hygienic material with a sufficient absorption rate, even if the absorption rate is increased due to the presence of the base material in the composite material, since the spherical particles have a very low specific surface area.

Surface salt concentration

The salt concentration at the surface of the particles of the water-absorbing resin before binding to the base material (hereinafter “surface salt concentration”) is preferably at least 50 mol%, more preferably at least 60 mol%, even more preferably at least 70 mol%, and even more preferably at least 80 mol%. If the surface concentration of salt before binding to the base material is too low, then the particles have low adhesion.

The limiting value of the surface concentration of salt in the particles of the water-absorbing resin included in the composition of the absorbing composite material, after binding to the base material, has no particular limitations, however, it is preferably 90 mol%. or less, more preferably 80 mol%. or less, even more preferably 60 mol%. or less. It is effective if the surface concentration of salt in the particles of the water-absorbing resin in the finished composite material is low, since in this case products in the atmosphere of moist air are less sticky. It is also very desirable because in this way the high ability of the absorbent composite material to distribute the aqueous solution is maintained even if the particles begin to come into contact as a result of swelling upon absorption of the aqueous solution by the composite material. To maintain a high absorption capacity, it is necessary to increase the salt concentration in the particles of the water-absorbing resin as a whole, and from the point of view of creating a high ability of the composite material to distribute liquid it is better if the surface has a lower salt concentration. Thus, it is desirable to reduce the surface salt concentration by increasing the internal salt concentration. Namely, it is preferable that the surface concentration of the salt is at least 10 mol%. lower, more preferably, at least 20 mol%. lower, even more preferably, at least 30 mol%. lower than the concentration of salt in the center of the resin particles. “At the surface” means an outer layer about 1 μm thick from the surface of the resin. It is desirable to control the concentration of salt at the surface simultaneously with the binding of the resin to the base material, since in this way it is possible to precisely balance the adhesion and absorption capacity.

The water-absorbing resin typically contains acidic groups such as carboxyl groups, sulfonic acid groups and their salts, and basic groups such as amino groups and their salts and the like. The value of the surface salt concentration reflects the fraction of groups neutralized with the formation of salts in the surface layer of particles of water-absorbing resin. According to the present invention, the salt concentration at the surface of the resin particles can be determined by impaired total reflection spectroscopy, in which the absorption of infrared radiation is analyzed. Since this method allows obtaining information on the structure of the surface layer with a depth of 1 μm, the degree of neutralization of the groups at the surface of the resin particles can be directly measured by the method of impaired total reflection spectroscopy. The degree of neutralization in the inner part is measured by the same method after cutting the resin particles using an ultramicrotome (Reichert, Ultracut N). For measurements using the device Bio-Rad FTS-575.

The measurements are further described with the example of polyacrylic acid used as a water-absorbing resin. To determine the proportion of carboxylic acid and carboxylate, the ratio of peak areas (1695/1558 cm ^-1 ) is calculated: peak area at 1695 cm ^-1 (material line of the carboxyl group C = O at 1774-1616 cm ^-1 ) and peak area at 1558 cm ^{- 1} (the material line of the COO group ^is 1616-1500 cm ^-1 ). The indicated fraction is determined on the basis of a calibration curve obtained as a result of measurements for standard samples of partially crosslinked polyacrylic acid, neutralized with 10 mol%, 30 mol%, 50 mol%, 70 mol%, 90 mol%. or 100 mol%. ammonium solution.

Surface strength

The surface strength of the particles of the water-absorbing resin before binding to the base material is preferably from 0.1 to 5.5 N, more preferably from 0.1 to 5 N, even more preferably from 0.2 to 4 N and even more preferably from 0.2 to 3 N. Surface strength is a parameter reflecting the probability of deformation of the surface of the particle. When particles of a water-absorbing resin, which absorbed moisture and swell for some time, are placed in a container and subjected to a load, the gel is moved and deformed so that it fills the gaps between the particles of the water-absorbing resin, which are laid in the container at intervals. Since surface strength is the modulus of elasticity of particles of a water-absorbing resin after they absorb liquid and acquire a real volume, its value indicates the degree of interaction between the gel particles and the likelihood of deformation of their surface. If the surface strength of the particles of the water-absorbing resin is high, this means that the particles of the water-absorbing resin are difficult to deform. If the particles are difficult to deform, then when the particles absorb the water-absorbing resin, a strong resistance to swelling occurs, which reduces the absorption capacity. If the surface of the particles is difficult to deform, the bonding area of the resin and the base material is reduced, thereby facilitating the separation of particles from the composite material. In the context of the present invention, the surface strength of the particles of the water-absorbing resin is determined as follows.

Equipment: Shimadzu Autograph AG-1.

Sample: 0.10 g of particles of water-absorbing resin are accurately measured and evenly distributed on the bottom of a cylindrical container with a height of 50 mm and an inner diameter of 20.5 mm, to the bottom of which a nylon sheet with a pore size of 75 μm is glued. Take a Petri dish with a diameter of 50 mm, place it in 0.90 g of saline and leave it in a cylindrical container with particles of water-absorbing resin for 1 hour to absorb liquid and swell.

Measurements: take a 1 kN load cell and attach a cylindrical rod with a diameter of 19.7 mm to it. The measurement range is set to 0.2 kN and, starting from the height at which the sensor is not loaded, lower the rod at a constant speed of 0.6 mm / min. The change in pressure on the sensor over time is recorded. Surface strength corresponds to the load (N) at the point of acquisition by the particles of the actual volume. The actual particle size of the water-absorbing resin is calculated based on the relative density of the saline solution of 1.010 g / cm ³ and the relative particle density of the water-absorbing resin.

Absorption capacity

In accordance with the present invention, the average absorption capacity of the particles of water-absorbing resin included in the composite material should be at least 50 g / g, preferably at least 60 g / g, more preferably at least 70 g / g.

In addition, for particles of water-absorbing resin, which is the object of the present invention, the absorption capacity of the water-absorbing resin under load or under pressure of 0.8 psi. an inch is preferably at least 20 g / g, more preferably at least 25 g / g, even more preferably at least 30 g / g. It is desirable that the particles of the water-absorbing resin have a high absorption capacity, since then the amount of water-absorbing resin used can be reduced.

In the context of the present invention, the absorption capacity of the particles of the water-absorbing resin means the amount of 0.9% saline solution that the particles of the water-absorbing resin can absorb, freely swelling in the absence of load. The absorption capacity of the particles of the water-absorbing resin is measured as follows.

0.05 g of particles of water-absorbing resin are uniformly placed in a bag of non-woven material similar to tea bags (60 × 40 mm), and immersed in 0.9% saline at 23 ° C. After 180 minutes, the bag is taken out, slanted by the corners for 10 minutes to drain and weighed. The same procedure is performed in the absence of particles of water-absorbing resin in the bag and determine the weight of the bag as such. The absorption capacity is calculated by the formula 4. The measurement is carried out 3 times and the average value is taken as the absorption capacity.

Absorption capacity of particles of water-absorbing resin (g / g) = {(weight of the bag after absorption) - (weight of an empty bag after absorption) - (weight of particles of water-absorbing resin)} / (weight of particles of water-absorbing resin) (formula 4)

In accordance with the present invention, the absorption capacity of the particles of the water-absorbing resin under pressure is measured as follows. 0.02 g of particles of water-absorbing resin are placed in an acrylic resin tube with an inner diameter of 25 mm and a length of 30 mm, at the bottom of which there is a non-woven nylon material with a pore size of 250 mesh, a smoothly moving cylinder is placed in the tube, thereby obtaining a measuring device , and the design is weighed. The load is created by placing a load of 278.33 g (corresponding to 0.8 psi) on the top of the measuring device cylinder, which device is placed in a 120 mm Petri dish containing 60 g of 0.9% saline. After 60 minutes, the measuring device is removed and placed on a Kimberly-Clark towel for draining water for 3 seconds, after the load is removed, the device is weighed and the absorption capacity under pressure is calculated according to formula 5.

Absorption capacity (g / g) of particles of water-absorbing resin under pressure = (weight (g) of the device after absorption - weight (g) of the device before absorption) / (weight of particles of water-absorbing resin) (formula 5)

For the production of hygiene products, such as disposable diapers, it is desirable to have an absorbent composite material with a tensile strength of 0.6 (N / 20 mm) or more, containing particles of water-absorbing resin with an absorption capacity of 70 g / g or more and absorption capacity under pressure 0.8 psi an inch of 20 g / g or more, since at such parameters it has the desired absorption properties both without load and under pressure. Such a water-absorbing composite material preferably consists of particles of water-absorbing resin and paper and / or fabric, more preferably, each particle of the water-absorbing resin is located at a distance from other particles in order to prevent blocking of the particles, even more preferably 90% by weight . or more particles of water-absorbing resin were associated with paper and / or fabric. Particles of water-absorbing resin with an absorbing capacity without load of 70 g / g or more and an absorption capacity at a pressure of 0.8 psi. an inch of 20 g / g or more can be obtained in the following ways. They can be obtained by polymerization of unsaturated carboxylic acid monomers, 70% or more of which are acrylic acid, in which 50% or more of the carboxyl groups are neutralized to form ammonium salts and 70% or more of the total number of monomers have neutralized carboxyl groups. In this case, the monomers include a compound containing in one molecule 2 or more unsaturated groups acting as a crosslinking agent, which compound is present in an amount of from 0.0005 to 0.1 mol%. the total number of monomer components. From 0.1 to 3 parts by weight of a compound containing two or more of such functional groups that can react with carboxyl groups can be used at any stage before or after polymerization. Radical polymerization is carried out using a redox initiator in an amount of from 0.005 to 0.5 mol%. the amount of unsaturated monomers. The reducing agent is used in an amount of from 0.0001 to 1 g per 1 mol of monomers. Also, if necessary, heating is carried out under conditions satisfying Formula 6. Preferably, the absorbent composite material is heated as a whole during production, and not the resin particles separately.

Y = -1.6X + 345 (formula 6)

(where Y is the heating time, min; X is the heating temperature, ° C).

Since the particles of water-absorbing resin thus obtained have a tendency to blocking, they are characterized by low rates, especially the absorption rate and absorption capacity under pressure, if these parameters are measured in the usual way, in which the particles of water-absorbing resin are in close contact with each other. However, these same particles give good results in terms of absorption rate, and absorption capacity without load, and absorption capacity under pressure, if these indicators are measured by the method described above, which is included in the present invention, in which the maximum realization of their absorption capacity is possible.

Particle size

The weighted average particle size of the water-absorbing resin used in the context of the present invention is preferably 100 to 2700 microns, more preferably 100 to 2100 microns, even more preferably 200 to 2100 microns and ideally 200 to 1400 microns. In terms of absorption, it is not preferred that the average particle size be too small. On the other hand, it is not preferable that the average particle size is too large, since it is difficult to select the coefficient of the total surface area so that it matches the desired range.

In accordance with the present invention, the particle size of the water-absorbing resin is determined by classification on sieves with mesh sizes of 106 μm, 212 μm, 300 μm, 425 μm, 500 μm, 600 μm, 710 μm, 850 μm, 1000 μm, 1180 μm, 1400 μm, 1700 microns and 2500 microns. In accordance with the present invention, the determined particle size is an intermediate value between the cell size of two screens, through one of which this particle passes, and through the other - does not pass. The size of the particles that pass through the sieve with a mesh size of 106 μm is taken to be 53 μm, and the size of the particles remaining on the sieve with a mesh size of 2500 μm is taken to be 2700 μm. As a result of this operation, the particles are classified by size 53 μm, 159 μm, 256 μm, 362.5 μm, 462.5 μm, 550 μm, 655 μm, 780 μm, 925 μm, 1090 μm, 1290 μm, 1550 μm, 1850 μm, 2100 μm and 2700 μm.

The proportion of particles of water-absorbing resin in the composite material of the present invention that pass through a sieve with a mesh size of 300 μm is preferably 50% or less, more preferably 40% or less. The proportion of particles that cannot pass through a sieve with a mesh size of 3000 μm is preferably 10% or less, more preferably 5% or less.

The particle size distribution of the water-absorbing resin in the absorbent composite material of the present invention is directly related to the absorption capacity of this absorbent composite material. For example, the absorption rate tends to increase with decreasing average particle size, and the degree of swelling in the direction perpendicular to the base material and the amount of liquid absorbed per unit area tend to increase with increasing average particle size. If we compare resin particles with the same weight, the area occupancy tends to decrease with an increase in the average particle size, i.e., swelling is less likely to block. If the particles are too large, the absorption rate of the particles as such is very low, however, the absorption rate of large particles in the composition of the composite material of the present invention increases due to the combination with the fibers, so it is preferable to use relatively large particles. From the point of view of both absorption capacity and absorption rate, it is desirable to use both relatively large particles of size 550 μm or more and relatively small particles of size 300 μm or less, preferably, the particle size distribution in this composite material has two or more peaks. The particle size corresponding to these two peaks differs, preferably 2 or more times, more preferably 3 or more times, even more preferably 4 or more times. If the particle size is different, the particles are packed most densely to each other, and when swelling large and small particles do not come into contact, that is, each particle maximally implements its absorption capacity.

Large particles

The absorbent composite material of the present invention preferably uses coarse particles. Large particles are particles ranging in size from 550 to 2100 microns. In order to increase the absorptive capacity per unit area of the absorbent composite material, it is desirable to use larger particles, however, if the particles are too large, the absorption rate is reduced, which, when used in an absorber in a hygiene product, can cause pain or other inconvenience due to protrusion. Therefore, the size of the large particles is preferably from 655 to 1850 μm, more preferably from 780 to 1550 μm, even more preferably from 925 to 1290 μm.

Since the absorption rate of such large particles is highly dependent on their shape, it is preferable to use ground amorphous particles obtained by a method including grinding and / or aggregated particles obtained by phase reversal suspension polymerization. Other particles than crushed amorphous particles or aggregated particles whose specific surface area (surface area / volume) is smaller can cause a decrease in the absorption rate.

The term "aggregated particles" in the context of this document means a cluster formed by combining two or more particles with an average size of from 10 to 550 microns (hereinafter referred to as primary particles). The distribution of primary particles in size does not have to be uniform; primary particles can include particles larger than 550 microns and less than 10 microns. That is, it is enough that the average size of the primary particles before aggregation lies in the range from 10 to 550 microns. It is desirable that the average size of the primary particles is small, since in this case the absorption rate of large particles increases. On the other hand, it is desirable that the average size of large particles be large, because then the surface area of the particle decreases after swelling and, therefore, the contact area of the water-absorbing resin with an object outside is reduced, that is, the user does not feel cold from contact with the water-absorbing resin. This is also desirable because the penetration of the swollen resin through the sheet located between the absorbent composite material and the body to the skin is prevented, even if the swollen primary particles are separated from the base material. Therefore, the most desirable average primary particle size is from 200 to 500 microns.

The concentration of salt at the surface of large particles, preferably 10 mol%. or more, more preferably, at 20 mol%. or more, even more preferably 30 mol%. or lower than the concentration of salt in the center of the resin particles. If crushed amorphous particles are used, it is particularly preferable to increase the absorption rate by introducing water into the particles as a result of the osmotic effect caused by the difference in salt concentrations on the surface and in the center of the particle, since the specific surface area of large particles is less than aggregated. It is also preferable to crosslink the surface of the particles in order to reduce the blocking effect when, upon swelling of the particles at the surface during absorption of the liquid, there is an obstacle to the penetration of the liquid into the particles. When aggregated particles are used as large particles, the absorption rate may decrease due to the gel blocking effect of the primary particles, that is, obstruction of the penetration of water from the outside into the large particles. Therefore, it is desirable to reduce the gel blocking effect, that is, to make the surface of the swollen particles dry by lowering the salt concentration at the surface of the primary particles or by stitching the surface layer of the primary particles.

The absorption capacity and absorption rate of the absorbent composite material of the present invention are preferably controlled by the use of large particles and other particles of water-absorbing resin, in which case the average particle size in the mixture is preferably from 10 to 2700 μm, more preferably 100 to 1000 microns, even more preferably 200 to 550 microns. When, in addition to large particles, other resin particles are included in the composite material of the present invention, in addition to large particles, it is desirable to add many particles of water-absorbing resin of a relatively small size. In this case, the content of particles passing through a sieve with a mesh size of 300 μm is preferably from 10 to 50% by weight. relative to all particles of water-absorbing resin in the absorbent composite material. If the particles of the water-absorbing resin are too small, the absorption capacity will be lower, therefore, the content of particles of the water-absorbing resin with a size of less than 100 μm should preferably be 10% by weight. or less. It is better if the content of particles of water-absorbing resin with a size of less than 212 microns is preferably 10% by weight. or less.

6. Base material

In the context of the present invention, “base material” means a material that can maintain the shape of a sheet.

Material

In the context of the present invention, the base material may be any sheet-shaped material, however paper and / or fabric is preferred. As used herein, “paper” means paper whose parameters are defined by the JISP00001 standard, and “fabric” is a general term for sheet-shaped sheet fiber products described by the JISL0206 standard. Depending on the method of forming the fabric, they are divided into textile fabric, knitted fabric, lace fabric, mesh and non-woven material. In accordance with the present invention, it is preferable to use textile fabric, knitted and non-woven fabric; Non-woven fabric is particularly preferred. Paper and / or fabric is desirable to use because they, unlike pulp and other short fibers, have morphological stability. Nonwoven fabric parameters are described in JISL0222.

The choice of base material does not have certain restrictions; a combination of several materials can be used. The fibers of the base material may be natural or artificial fibers, and a combination of several types of fibers may also be used. These fibers can be both long and short. They can also be processed to increase strength and hydrophilicity. From the point of view of liquid absorption and water permeability, the use of hydrophilic rather than hydrophobic fibers is more favorable. It is also better to use continuous long rather than short fibers, as they provide good fluid permeability.

Of hydrophilic materials, cellulosic is particularly suitable for the base material. In the context of the present invention, a cellulosic backing material means a fabric and / or paper made mainly from cellulose and a fabric and / or paper made from cellulose fibers, it is particularly desirable to use a non-woven cellulosic material. As cellulosic fibers, cellulose derivatives obtained by esterification and esterification can be used. They can also be mixed with other fibers. Types of cellulose include natural fibers such as cotton and hemp, and regenerated fibers such as viscose fiber, viscose modal fiber, lyocell, cupra and the like. It is preferable to use regenerated fibers, especially regenerated fibers made from raw cotton.

The form

The shape of the base material has no particular limitations, the thickness of the material is preferably from 0.001 mm to 1 cm, more preferably from 0.01 mm to 5 mm, even more preferably from 0.05 mm to 3 mm, ideally from 0 , 1 mm to 1 mm. The weight is preferably from 0.1 g / m ² to 1 kg / m ² , more preferably from 0.5 g / m ² to 500 g / m ² , even more preferably from 1 g / m ² to 100 g / m ² . From a strength point of view, too thin or too light a material is not preferable.

Tensile strength

In accordance with the present invention, the tensile strength after absorption of the saline solution is preferably at least 0.6 N / 20 mm, more preferably from 0.6 to 5000 N / 20 mm, even more preferably from 0.7 up to 500 N / 20 mm, even more preferably from 0.85 to 100 N / 20 mm, ideally from 1 to 100 N / 20 mm.

In accordance with the present invention, the direction in which the strength of the material is maximum is defined as the longitudinal direction, and the direction perpendicular to this direction is determined as the transverse direction; the strength preferably corresponds to the indicated range in the transverse direction (i.e., both in the longitudinal and in the transverse direction).

In accordance with the present invention, the tensile strength after absorption of the saline solution means the tensile strength measured after the base material has absorbed the saline solution. Sometimes hygienic materials continue to be used without substitution after they have absorbed liquids. It may also be necessary to repeatedly absorb the liquid after it once happened. If the absorber continues to be used after it has absorbed liquid, the situation becomes similar to that when the material is under pressure and holds water inside. If the base material breaks under load, its liquid permeability, liquid distribution capacity and absorption capacity deteriorate. From the point of view of wear resistance of the absorber, it is preferable that the base material retain strength even after absorption of the saline solution. Preferably, the base material has high strength, since low strength is ineffective when the manufacturing process of the composite material includes a step in which the base material is impregnated with water. However, by using an exceptionally strong base material, absorption capacity cannot be further enhanced.

The tensile strength after absorption of the saline solution is determined as follows.

Sample: a base material in the form of a rectangle of 15 × 2 cm in size (samples are prepared in different directions).

Equipment: tensile testing device (Shimadzu Autograph).

Methods: 700 g of 0.9% saline solution is placed in a 1 liter beaker and the base material is immersed in it for 10 minutes. Then the base material is removed and left for 1 minute on a Kimberly-Clark towel, and then fixed in the indicated device at points located 2.5 cm from the edge so that the distance between them is 10 cm. The base material is stretched at a speed 10 mm / min to rupture, record the force at the moment of rupture. The maximum value is strength in N / 20 mm. If the strength value of the material depends on the direction, measurements are performed for several different directions.

Absorption capacity, absorption rate

Absorption capacity and absorption rate are indicators of hydrophilicity and liquid permeability of the base material. Below they are described in detail.

In the context of the present invention, the absorbency of the base material means the coefficient of weight gain of the base material after 60 minutes of absorption of 0.9% saline, measured as follows.

A round piece with a diameter of 59.5 mm is cut from the base material, the wire is weighed and passed through it at a distance of 1 cm from the edge. 500 g or more of a saline solution with a temperature of 23 ° C is poured into a 1 liter beaker, into which the base material is immersed together with the wire. After 60 minutes, the base material and the wire are removed from the brine and suspended for 10 minutes so that the material does not come into contact with anything. After 10 minutes, the wire is removed, and the total weight of the wet base material and its associated water is measured.

The absorption capacity of the base material is expressed by formula 7.

Absorption capacity of the base material (g / g) = weight after absorption (g) / weight before absorption (g) (formula 7)

In accordance with the present invention, the absorption capacity of the base material is preferably at least 6 g / g and not more than 200 g / g, more preferably at least 8 g / g and not more than 100 g / g, even more preferably at least 10 g / g and not more than 50 g / g and ideally at least 12 g / g and not more than 30 g / g.

Due to the fact that the fibers of the absorbent composite material have a higher absorption rate than the particles of the water-absorbing resin, the absorption of the base material occurs at an earlier stage than the absorption of particles of the water-absorbing resin. It is desirable that the base material has a higher absorption capacity, since then faster absorption of the liquid in the early stages is ensured. Since the absorption of the base material occurs mainly as a result of the capillary effect, under load, the liquid can be released and create a sensation of moisture when used. However, if resin particles are bonded to the fibers of the base material, water-absorbing resins absorb the liquid, drawing it away from the base material. As a result, re-wetting under load or the formation of steam during use is not enough.

In the context of the present invention, the absorption rate of the base material means the speed at which the base material with a width of 2 cm absorbs 0.9% saline in the perpendicular direction.

The absorption rate of the base material is preferably at least 0.35 mg / s and not more than 100 mg / s, more preferably at least 0.45 mg / s and not more than 50 mg / s, even more preferably at least 0.55 mg / s and not more than 30 mg / s and even more preferably at least 0.65 mg / s and not more than 10 mg / s.

In particular, the absorption rate of the base material is measured as follows.

Sample: a rectangular piece of base material measuring 10 × 2 cm.

If the material has differences in the longitudinal and transverse directions, prepare 2 or more samples in different directions.

Equipment: electronic scales, Petri dish with a diameter of 90 mm.

Methods: the Petri dish is placed on an electronic scale, the base material is suspended vertically 10 cm above the Petri dish. The Petri dish is removed from the balance and filled with 60 g of 0.9% saline, suspended on other scales. The Petri dish is returned to the balance, hand supporting the lower edge of the base material so that it does not touch the solution, the scale of the scales is set to 0. The base material is carefully immersed in the solution and the balance is periodically taken. The time (s) and the absolute value (mg) of the balance are plotted and the gradient (mg / s) between 120 and 240 s is determined, which is the absorption rate. If the material has pronounced directions, perform several measurements for different directions and take the value for the direction in which absorption is the fastest as the absorption rate.

It is preferable that the absorption rate of the base material be different for different directions, since in this case the material is well permeable to liquid in a certain direction, and the liquid is easily removed and distributed in this direction, which ensures balanced absorption by this absorber.

The ratio of tensile elongation and strength in the longitudinal and transverse directions

If the material has pronounced directions, the values of strength and elongation in these directions are different. As indicated above, in the context of the present invention, the direction in which the strength is maximum is considered longitudinal and the direction perpendicular to the longitudinal is considered transverse.

The ratio of the tensile strengths in the longitudinal and transverse directions is preferably at least 1.2: 1, more preferably at least 1.5: 1, even more preferably at least 2: 1, but no more than 10: 1.

The ratio of tensile elongation in longitudinal and transverse directions is preferably at least 1: 1.2, more preferably at least 1: 1.5, even more preferably at least 1: 2, but not more than 1:10. The elongation and strength of the base material can be determined in the same way as the strength of the base material after absorption of the saline solution, by tensile testing of the dry base material without immersing it in brine. The tensile test is continued until the base material ruptures, the maximum recorded force is the strength value of the base material, and the elongation at the corresponding time is destructive elongation under tension.

Wetting angle

In accordance with the present invention, it is preferable to use a non-woven fabric having a contact angle of 130 ° or less.

In the context of the present invention, the contact angle is defined as the angle formed 10 minutes after contacting the base material and a 44% aqueous solution of ammonium polyacrylate with a viscosity of 74 cP at room temperature. This angle is measured using a CA-X150 goniometer manufactured by FACE (Kyowa Interface Science). The solution is prepared by adjusting the viscosity of a 44% aqueous solution of ammonium polyacrylate (70 to 110 cP) manufactured by Wako Pure Chemical by adding water. Viscosity is measured with a rotating disk viscometer.

The wetting angle is preferably 130 ° or less, more preferably 120 ° or less, even more preferably 110 ° or less, ideally 100 ° C or less. The affinity of the base material for water and the affinity of the base material for the water-absorbing resin increase with decreasing wetting angle, while the absorption capacity and adhesion increase.

7. A method of obtaining an absorbent composite material

The absorbent composite material of the present invention is made from particles of a water-absorbing resin and a base material, preferably by a method comprising the step of bonding the particles of a water-absorbing resin to a base material.

The choice of the binding method does not have certain restrictions; it may be one of those methods that satisfy the above conditions.

Examples of bonding methods include methods for weaving a water-absorbing resin with a base material, and methods for using adhesives, and a method comprising impregnating a water-absorbing resin and / or base material with water in an amount of from 10 to 3000 weight is preferred. parts of water per 100 weight. parts of the water-absorbing resin and the subsequent removal of water while maintaining contact between the water-absorbing resin and the base material. The amount of water is preferably from 20 to 2000 weight. parts or, more preferably, from 50 to 1000 weight. parts per 100 weight. parts of particles of water-absorbing resin. This bonding method is preferred because it does not require the use of glue, which is a contaminant. When using this method, some fibers penetrate the water-absorbing resin, which is desirable from the point of view of absorption speed and absorption capacity. It is preferable to use more water, since this increases the adhesion, however, the use of too much water is inefficient due to the increase in drying time.

Absorbed water may contain impurities. Examples of impurities include cations, such as sodium ions, ammonium ions, and water-soluble organic compounds, such as iron ions, chlorine ions and other anions, acetone, alcohols, esters and amines. Acidic or basic compounds may be used to adjust the pH of the water-absorbing resin and / or absorbent composite material. From the point of view of ensuring the contact of the water-absorbing resin with the base material and absorption capacity, it is desirable to use ion-exchanged or distilled water without any impurities.

To impart the desired properties to the finished absorbent composite material, it is preferable to dissolve and / or disperse substances of deodorizing or other action in water. Examples of deodorants that can be used in this case include organic and inorganic deodorants. When a water-insoluble deodorant is used, it is desirable to simultaneously use a dispersant or surfactant. In addition, inorganic deodorants can be dispersed in water without the use of a dispersant by reducing the particle size to a few nanometers, therefore, it is preferable to use finely dispersed inorganic deodorants without a dispersant.

The choice of the method of moisturizing does not have certain restrictions; examples include immersion in a water bath, spraying water, contact with a wet body, keeping in a humid atmosphere, etc. Of these methods, spraying is most preferred due to simplicity from the point of view of industrial embodiment and regulation of water content. It is preferable to use such a water sprayer, which allows you to evenly distribute water in the fabric or other base material. If the water content is very different in different parts of the base material, the particle size of the resin in the dried absorbent composite material will be heterogeneous, because the amount of water absorbed by the water-absorbing resin after being brought into contact with the base material and before the drying stage will be different in different areas, which will cause differences in the degree of foaming caused by the removal of water during the drying phase. An absorbent composite material with inhomogeneous resin particles may not meet customer requirements.

When wetting the base material and binding it to particles of a water-absorbing resin, the amount of water in the base material preferably corresponds to a range of from 50 to 500% by weight. To increase the adhesion of the particles of the water-absorbing resin to the base material, it is preferable to increase the water content, however, if the water content is too high, the surface of the drum used in accordance with the production method described below will be covered with a large amount of water, which causes the particles of the water-absorbing resin to adhere to different parts of the drum, preventing them from entering the wells. Of course, too low a water content adversely affects the adhesion of the base material to the resin particles. Therefore, the water content should be in the range from 50 to 200% by weight, more preferably from 80 to 150% by weight.

In order to moisten the base material, the particles of the water-absorbing resin may also contain water, which increases their adhesion, however, due to the fact that the particles of the water-absorbing resin in this case will adhere to other objects, in addition to the base material, it is preferable to dry the particles of the water-absorbing resin before binding to states when they do not adhere to other objects or other particles of resin. The water content in the particles of the water-absorbing resin in this case is preferably from 1 to 50% by weight, more preferably from 5 to 30% by weight.

Examples of contacting methods include dispersing particles of the water-absorbing resin onto the base material from above; fixing particles of water-absorbing resin in the holes on the surface of the drum, followed by moving these particles of water-absorbing resin from the holes to the surface of the base material; filling the drum, on the surface of which there are holes, with particles of water-absorbing resin, followed by extrusion of particles from the inside of the drum and placing them on the surface of the base material. The preferred method is one that allows the particles of the water-absorbing resin to be placed so that they do not touch each other after swelling, since in this case the absorption capacity of the particles of the water-absorbing resin is maximally realized.

Any method may be used to remove water. This is, for example, drying by heating, blowing with dry air or nitrogen, vacuum drying, freeze-drying, azeotropic distillation, fluid-bed drying, micro-network drying and the like, heating drying is preferred. The heating conditions correspond, preferably, from 1 to 1000 s at 70 - 350 ° C, more preferably from 1 to 1000 s at 100-340 ° C, even more preferably from 1 to 1000 s at 120-330 ° C, ideally - from 1 to 1000 s. at 150-300 ° C. The higher the temperature, the shorter the drying time, however, prolonged curing at high temperatures can adversely affect the absorption capacity of some types of resin. Simultaneously with drying, surface treatment such as crosslinking, for example, can be carried out. The removal of water can be carried out at any stage until the finished product is obtained, preferably immediately after wetting to prevent deterioration of the quality of the water-absorbing resin.

The preferred method of obtaining an absorbent composite material

The following describes an acceptable example of a method of manufacturing an absorbent composite material in accordance with the present invention.

FIG. 1 is a diagram of an acceptable device for manufacturing an absorbent composite material of the present invention. The base material is fed from a roll of fabric (a), moistened with a device such as a water spray (b), turning it into a wet base material (c). Then, on one of the surfaces of the wet base material, the resin particles are blown out of the rotary drum (e1) for applying the resin particles, into the wells of which the resin particles (f) are supplied from the resin particle supply unit (d1). The resin particles are then blown onto the other surface of the wet base material from a rotary drum (e2) for applying resin particles, into the wells of which resin particles (f) are supplied from the resin particle supply unit (d2). After that, to control the absorption capacity of the absorbent composite material, fine particles of resin are uniformly applied using a small particle feed unit (i) and the base material with resin particles bonded to both of its surfaces is dried by passing through a drying unit (g), resulting in a composite material with resin particles firmly bound to it.

For the described method, the design of a rotating drum for applying resin particles is important, due to which the particles of water-absorbing resin are placed on the surface of the base material. On the surface of the drum in predetermined places there are many holes in which particles of water-absorbing resin can be placed. These wells are preferably located so as to reduce the likelihood of particles of water-absorbing resin in contact with each other. There is an optimal arrangement of the holes at which the absorption capacity of the absorbent composite material is maximum. This is an arrangement in which there is a space between adjacent resin particles allowing the particles to swell upon absorption of the liquid, and in which a larger number of particles of water-absorbing resin can be placed on the base material.

In accordance with this method of obtaining the outer diameter of the holes of the holes on the surface of the drum is preferably from 1 to 3, more preferably from 1.2 to 2 maximum diameters of the supplied particles of the water-absorbing resin. In the context of this document, the "outer diameter of the holes of the holes on the surface of the drum" means the largest value of the distance between any two points on the outer border of the holes on the surface of the drum.

If the outer diameter of the hole is too large, it is difficult to achieve stable operation, since several particles of water-absorbing resin may fall into one well or the particles of resin that fall into the holes may with high probability fall out of them. On the other hand, if the outer diameter of the hole is too small, particles of water-absorbing resin from the holes can be removed, sticking to parts other than the holes due to the action of static electricity, etc., even if they are held in the holes by the suction force.

With regard to the shape of the hole, the outer boundary of its surface on the surface of the drum may be of any shape, including having no angles, for example round or oval, having angles, for example triangular, rectangular, and an irregular pentagon. A specific shape with or without corners is preferable from the point of view of the drum manufacturing process, and a shape without corners is desirable from the point of view of both the production of the drum and the placement and removal of particles from the holes.

As for the design of the hole between its outer boundary on the surface of the drum and the inner part of the drum, it can be unchanged along the entire length from the outer surface of the drum to the inner one, or it can expand to the inner surface, or may already be on the inner surface. From the point of view of ease of placement and removal of particles of water-absorbing resin, it is desirable that the holes are already on the inner surface of the drum than on the outer.

The depth of each well is preferably from 0.3 to 2, more preferably from 0.5 to 1.5, even more preferably from 0.7 to 1.2, the average particle size of the water-absorbing resin supplied to the drum. If the wells are too small, then particles of water-absorbing resin can be removed from them, sticking to parts other than the holes due to the action of static electricity, etc., even if they are held in the holes by the suction force. If the wells are too deep, several particles can be placed in one well, making it difficult to adjust the amount of resin present in a bound form in the finished absorbent composite material, in addition, it can also make it difficult to remove particles of water-absorbing resin from the wells and, thus, impair the stability of the process.

At the bottom of each well on the surface of the drum in accordance with this manufacturing method, there is preferably an opening through which gas can pass for blowing particles of the water-absorbing resin. The inner diameter of this hole is preferably smaller than the size of the small particles of water-absorbing resin supplied to the drum. If these holes are larger than small particles, then particles smaller than the diameter of the holes, instead of being blown onto the base material, can enter the inner cavity of the drum and accumulate there, creating obstacles to stable operation. These openings may be of any shape that allows gas to easily pass from inside the drum to the outside. In order to avoid clogging of these holes with particles of water-absorbing resin, it is preferable that they are wider from the side of the inner cavity of the drum.

With regard to the placement of particles of water-absorbing resin in the drum, it is preferable that the particles are placed under the action of the suction force resulting from the creation of vacuum inside the drum. The pressure difference inside and outside the drum in this case is preferably from 0.01 to 500 Torr. If the pressure difference is too small, the particles placed in the wells will easily fall out of them. On the other hand, if it is too large, there will be too many particles in the wells that are difficult to push out. Therefore, the pressure difference should be in the range of preferably from 0.05 to 100 Torr, more preferably from 0.1 to 50 Torr, even more preferably from 0.5 to 5 Torr. The described method, which uses suction, is especially good because it not only increases the likelihood of particles of water-absorbing resin being placed in the wells, but also prevents the particles placed in the holes from sticking out to other than the holes sections of the drum before they are blown onto the substrate from hydrophilic material.

According to the present production method, it is preferable to remove the static charge from the drum, since the static electricity generated by the operation of the drum can destabilize the movement of particles of the water-absorbing resin.

To control the coefficient of the total surface area, etc. preferably, after placing large particles with a drum, apply resin particles having different sizes. These particles can be deposited only on one surface or on both surfaces of the fabric during the reverse course of the fabric after applying the particles to one of the surfaces. To prevent the separation of these particles, it is advisable to wet the backing material with water again before applying them. The choice of method for applying the particles is not particularly limited, and preferably one that allows the particles to be applied uniformly is used.

According to the present production method, it is preferable to move the base material. The method of moving the base material in this case does not have certain restrictions. Examples of methods for moving the base material include those methods in which the base material is moved without support from above or below, and those in which the base material is moved using a conveyor belt or other element supporting it from below. If particles of water-absorbing resin are applied to both surfaces of the base material, it is preferable to use a conveyor belt at the stage of moving below the drum surface of that surface of the base material, the binding of particles to which is carried out later, since this prevents the resin already deposited on the back surface of the base material from being separated into during the blowing of particles of water-absorbing resin from the drum. It is also preferable to use a conveyor belt at the final stage of water removal and drying, since this reduces the shrinkage of the base material, which is likely when water is removed from the base material and when it is dried.

Preferably, the particles of the water-absorbing resin used in accordance with the present production method have a high surface concentration of salt, as this allows for enhanced adhesion when blowing particles onto the base material. However, it is not preferable that the surface concentration of salt in the finished product is too large. That is, it is desirable to adjust the salt concentration on the surface after the particles of the water-absorbing resin adhere to the base material. From the point of view of productivity, it is better to adjust the salt concentration simultaneously with the drying stage, and not after it. The surface salt concentration is preferably at least 10% less, more preferably at least 20% less, even more preferably at least 30% less than this value before said treatment.

8. Characterization of absorbent composite material

Absorption capacity

In the context of the present invention, the absorption capacity of an absorbent composite material means the amount of 0.9% saline solution absorbed over 3 hours under free absorption conditions. More specifically, a round piece of absorbent composite material with a diameter of 59.5 mm is prepared and its absorption capacity is measured in the same ways as the absorption capacity of the base material. If there are unbound particles of water-absorbing resin or particles are separated, these particles of water-absorbing resin are collected by filtration and left for 10 s on a Kimberly-Clark towel to remove excess water, and their weight is taken into account when measuring. When measuring the absorption capacity of an absorbent composite material in which almost 50% by weight. particles of water-absorbing resin are in an unbound state, this absorbing composite material is placed in a bag like tea bags and perform measurements in accordance with the method of measuring the absorption capacity of the particles of water-absorbing resin.

The absorption capacity of the absorbent composite material is preferably at least 40 g / g, more preferably at least 45 g / g, even more preferably at least 50 g / g.

The amount of fluid absorbed by a surface unit

The amount of absorption per unit surface is important because it is an indicator of the absorption capacity of an absorbent composite material. The amount of fluid absorbed by a surface unit is calculated by formula 8 using the results of the measurements described above.

The amount of liquid absorbed by a surface unit (g / cm ² ) = (total weight after absorption (g) - weight of the absorbing composite material (g)) / area of the absorbing composite material (cm ² ) (formula 8)

Preferably, the amount of liquid absorbed by the surface unit is large, preferably, this value is not less than 0.4 g / cm ² , more preferably not less than 0.7 g / cm ² , even more preferably not less than than 1 g / cm ² .

Absorption capacity under pressure

The absorption capacity under pressure of the absorbent composite material of the present invention is expressed as the amount of 0.9% saline absorbed over 3 hours of absorption under pressure. More specifically, this value is measured using a round piece of absorbent composite material with a diameter of 59.5 mm, as follows.

The measuring device is described in general terms with reference to FIG. 2. As shown in FIG. 2, the measuring device consists of weights 1, a container 2 placed on the scales 1, a suction pipe 3, a pipe 4, a glass filter 6 and a measuring element 5 placed on the glass filter 6. There are holes 2a in its lower part in the container 2 and 2b on the side. A tube 3 for sucking in air is inserted into the hole 2a, and a pipe 4 is connected to the hole 2b. The container 2 contains a predetermined amount of saline solution 12. The lower end of the air suction pipe 3 is immersed in saline solution 12. The diameter of the glass filter 6 is 70 mm. The container 2 and the glass filter 6 are connected to each other via a conduit 4. The position of the glass filter is adjusted so that it is at the same height as the lower end of the air suction pipe 3. As shown in FIG. 3, in the measuring element 5 there is filter paper 7, a support cylinder 9 and a load 11. Advantec No. 2 paper with a diameter of 60 mm is used as filter paper 7. In the measuring element 5, the filter paper 7 and the support cylinder 9 are placed on the glass filter 6 in this order, and the load 11 is located inside the support cylinder 9. The inner diameter of the support cylinder 9 is 60 mm. The weight of the load 11 is chosen so that it provides a uniform load equal to 0.8 pounds / sq. inch per absorbent composite material 13. Absorption capacity under pressure of the absorbent composite material is measured using a measuring device of the design described. The following explains the measurement method. Firstly, preliminary preparation is required, which consists in filling the container 2 with a predetermined amount of saline solution 12 and installing a tube 3 for sucking air in the container 2. Then, filter paper 7 is placed on the glass filter 6. At the same time, absorbent composite material 13 is placed inside the support cylinder 9. and load 11 on it. Then the supporting cylinder 9 is placed so that its center coincides with the center of the glass filter 6. After installing the supporting cylinder 9, the weight W (g) of saline solution 12 is measured every 10 s, oshchenilas absorbent composite pictures 13, using the balance 1. The absorption capacity under pressure of the absorbent composite is determined by the formula 9.

Absorption capacity under pressure of an absorbent composite material (g / g) = weight W (g) / weight of an absorbent composite material (g) (formula 9)

Absorption capacity under pressure of an absorbent composite material under a load of 0.8 psi. an inch is preferably at least 15 g / g, more preferably at least 16 g / g, even more preferably at least 18 g / g. The amount of fluid absorbed by a surface unit under pressure can be measured in the same way as the amount of fluid absorbed by a surface unit without load. The amount of fluid absorbed by a surface unit under a pressure of 0.8 psi. an inch is preferably 0.1 g / cm ² , more preferably at least 0.15 g / cm ² , even more preferably at least 0.2 g / cm ² .

An absorbent composite material having an absorption capacity of 40 g / g or more, absorption capacity at a pressure of 15 g / g or more with a load value of 0.8 psi. an inch and a tensile strength of 0.6 (N / 20 m) or more, is highly absorbent and durable and can be successfully used in the manufacture of disposable diapers and other hygiene materials. Its absorption capacity is preferably at least 45 g / g, more preferably at least 50 g / g, even more preferably at least 55 g / g. Its absorption capacity under a load of 0.8 psi. an inch is preferably at least 16.5 g / g, more preferably at least 18 g / g, even more preferably at least 20 g / g.

Absorption capacity after 1 min

Absorption capacity after 1 min is an indicator of the initial rate of absorption of the liquid. Due to the fact that materials for such purposes as, for example, used for the production of disposable diapers, must absorb body fluids instantly, it is preferable that the absorption capacity after 1 min of absorption be higher. The absorption capacity after 1 min is determined by the formula 10. More specifically, this value is measured as follows.

A piece of 2 cm long and 7 cm wide is cut from the absorbent composite material and weighed. A 700 cm ³ saline solution is poured into a 1000 cm ³ beaker. A tea bag with a length of 80 cm and a width of 70 cm is weighed, immersed for absorption in water for 1 min, centrifuged and again weighed. This weight is divided by the weight of the sachet before absorption and the sorption capacity of the sachet is obtained after 1 min. A bag of the same size is weighed and a sample of absorbent composite material is placed in it. In order for the package to be quickly removed from the liquid, a cord equipped with a clip is attached to it; the package is carefully and quickly immersed in liquid so that the material does not bend or curl. After 1 min, the bag is quickly pulled out of the glass by the cord, the clamp is removed, the bag is centrifuged at 150 g for 3 minutes and weighed. Absorption capacity after 1 min is determined by subtracting the amount of liquid absorbed by the package from the total weight and dividing the result by the weight of the absorbing composite material before absorption. Centrifugation begins within 15 seconds after the absorbent composite has been removed from the liquid.

Absorption capacity after 1 min (g saline / g) = (weight after centrifugation (g) - weight of the bag (g) · absorption capacity of the bag after 1 min) / weight of the absorbent composite material (g) (formula 10)

Bending resistance

The bending resistance of the absorbent composite material is determined by method D (heart-shaped loop method) described in JISL1096. The values for the front and back surfaces are different if the size and distribution of particles on them are different; in accordance with the present invention, the value obtained for a softer surface, in other words, a larger value, is taken as the value of bending resistance. Bending resistance is preferably 90 mm or less, or more preferably 85 mm or less.

9. The method of using absorbent composite material

A preferred method for using the absorbent composite material of the present invention is to use products for absorbing body fluids as a component. The use of this composite material as an integral element of absorbent articles is explained below.

Products for absorbing body fluids

In the context of the present invention, articles for absorbing body fluids are absorbent articles consisting of a liquid permeable sheet, a liquid impermeable sheet, and interposed therebetween to form a layered structure of the absorbent composite material; These include all products that can absorb body fluids. In accordance with the present invention, the type of absorbed body fluid is not particularly limited, and examples of fluids include urine, menstrual blood, breast milk, loose stools and the like. There are also no particular restrictions on the shape of the product, and acceptable examples include diapers, sanitary napkins, incontinence pads, milk pads.

In combination with a liquid-permeable and liquid-impermeable sheet, the absorbent composite material of the present invention may form part of an absorbent body product having a high ability to absorb bodily fluids, while being thin and light. Due to the low probability that the absorber will move or move inside the absorbent product during use, it is also capable of stable absorption of body fluids. In addition, due to the higher proportion of water-absorbing resin than in conventional products for absorbing body fluids, the amount of absorbed liquid released under load (re-hydration) is small, and the part adjacent to the body always leaves a feeling of comfort.

In accordance with the present invention, a liquid-permeable sheet may be any sheet material through which water poured onto it passes, preferably a fabric described by JISL0206. According to the method of forming the sheet, the fabrics are divided into textile fabric, knitted fabric, lace fabric, mesh and non-woven material, and textile fabric, knitted or non-woven fabric, more preferably non-woven fabric, is preferred for use in accordance with the present invention as a liquid-permeable fabric. . It is preferable to use a sheet having low water absorption, made of polyethylene, polypropylene or other polyolefins in order to reduce the feeling of moisture on the skin of the user and increase comfort; it is preferable to use a sheet made of polyolefin, which, by appropriate treatment, is given water permeability or hydrophilicity properties, so that it can quickly transport body fluids.

In accordance with the present invention, a liquid permeable sheet may be any water permeable sheet material. From the point of view of preventing moisture sensation, a material with good gas permeability is preferred.

In the context of the present invention, it is sufficient that the product for absorbing body fluids consists of at least a liquid-permeable sheet, a liquid-impermeable sheet and placed between them to form a layered structure of the absorbent composite material, however, between the liquid-permeable sheet and the absorbent composite material and / or other materials may also be present between the liquid impermeable sheet and the absorbent composite material. Other material may also be external to a liquid impermeable sheet or a liquid permeable sheet.

Materials that can be used in this case include fiber materials, such as pulp, granular materials, such as particles of water-absorbing resin, sheet materials, such as various fabrics, paper and the like. These materials may be associated with a water-absorbing composite material that is an object of the present invention. These materials may be bonded, using glue, or directly, to particles of the water-absorbing resin of the absorbent composite material of the present invention. Products for absorbing body fluids preferably include a tape or elastic element for securing the product to the wearer's body, wings to prevent leakage on the sides, and the like.

Products for the absorption of body fluids, which are the object of the present invention, can have any shape: square, round, triangular, oval, combined trapezoidal or irregular. A rectangular, oval or similar shape, characterized by a larger length and a smaller width (in a direction perpendicular to the length), is suitable when the product is a diaper, sanitary pad, incontinence pad, etc., because it matches the shape perineum of the user. In FIG. 4 shows illustrative examples of the shape of the absorbent composite material, characterized by a larger length. Elements may also be provided for connecting the lap composite with other elements.

If the absorbent composite material has a shape having side lap members in which there is no water-absorbing resin, it is preferable that the proportion of the water-absorbing resin and the area occupancy by the resin of the absorbent composite material are adjusted to the desired values without taking into account the side elements.

A given absorbent composite material or a combination of two or more composite materials may be used in a product. To make the finished product thin, it is preferable to use one composite material. In order to obtain a product with increased absorption capacity, it is preferable to use more than one composite material. In this case, the composite materials may be stacked or in a row. They can be the same or different shapes. To effectively increase the absorption capacity, it is preferable that they overlap each other only in the place where body fluids are released, and to prevent leakage, they should overlap in areas of probable leaks.

There are no particular restrictions on the position of the absorbent composite material in the product for absorption of body fluids; the sheet of absorbent composite material may be fully unfolded or have wrinkles or folds.

Laying absorbent composite material in an article for absorbing body fluids

If the absorbent composite material of the present invention is used as a component of products for absorbing body fluids, the edges of the absorbent composite material are preferably folded, thereby preventing leakage of body fluids at the edges. The term "edge" in the context of this document means a zone 15 cm wide from the outer border of the sheet of absorbent composite material. Which part is bent does not have certain restrictions if it is within 15 cm from the outer border, preferably 12 cm, more preferably 8 cm, even more preferably 5 cm and ideally 3 cm. In accordance with the present invention the position in which the absorbent composite material is bent means that a certain part of the absorbent composite material does not lie in the same plane as the absorbent composite material when this absorbent composite material is stretched without applying redundant effort, and pin to the board with thumbtacks.

Folding can be carried out both in the direction of the liquid permeable sheet, as shown in FIG. 5, and in the direction of the liquid impermeable sheet, as shown in FIG. 6. When another piece of material lies in a plane different from that in which the first fold is located, as shown in FIG. 7, this part is called the second fold.

The folding of the composite material can be carried out once, twice or many times. Several folds are more effective in terms of preventing leakage, however, in this case, the thickness increases greatly, so the number of folds should be chosen so as not to distort the shape of the composite material. If several folds are used, their direction and angle can be chosen arbitrarily. These can be accordion folds, as in FIG. 8, or formed by multiple folding in the same direction as in FIG. 9. The part folded once can be bent again to form a double fold, as in FIG. 10. It is also possible threefold, etc. folding. As shown in FIG. 11, the fold does not have to be flat.

The presence of a fold along the edge of the absorbent composite material prevents leakage, since, thanks to a certain thickness of the fold, it acts as a barrier to the spread of liquid. In addition, the bent portion can also prevent leakage after the liquid has reached this area, since the absorption capacity of the bent portion is higher than that of the non-bent portion.

The absorbent composite material may be bent on all sides or only partially. If the absorbent composite material has a shape characterized by a larger length and a smaller width, such as a rectangle, oval, etc., leaks are more likely in the direction of a shorter measurement, therefore, leakages can be prevented with minimal folding of the material, bending only long sides of absorbent composite material. In this case, it is preferable to create such a shape of the absorbent composite material, which either has an element for folding, as in FIG. 12A, or slots to form a crease, as in FIG. 12V When it is known in which section of the material the absorption of body fluids should be carried out, it is advisable to place a fold on the edge near this section. In FIG. 12, the area marked with dots means the curved part.

The length of the bent portion has no particular limitations, however, it is preferably at least 2 cm, more preferably at least 5 cm, even more preferably at least 7 cm, ideally at least 10 see. The longer the bent part, the more pronounced the effect of preventing leaks.

Folding can be carried out in one place or in more than one place. The folds may be continuous or be multiple folds with gaps between them.

The folds can have any width, however, preferably, the overlapping part formed as a result of folding has a width of from 0.1 to 100 mm, more preferably from 1 to 70 mm, even more preferably from 5 to 40 mm, ideally from 5 to 20 mm. If the crease is very narrow, it provides little resistance to leakage, on the other hand, and if the crease is too wide, the gain is small.

In accordance with the present invention, when an article for absorbing body fluids is deployed on a flat board without applying excessive force and the four corners are fixed with buttons, the bending angle is the angle between the plane of the body for absorbing body fluids and a straight line connecting the point where the bent portion exits from the plane of the product to absorb body fluids, and the point farthest from this plane. When there are several folds, only the first is taken into account. Bending angles are shown in FIG. 5, 6 and 11. The bending angle is preferably greater than 0 °, more preferably at least 30 °, even more preferably at least 60 °, ideally at least 90 °.

The bent part can be fixed with glue. Fixing the bent portion with glue is desirable, as this avoids slipping of the absorbent composite material. The adhesive may be applied to the inner surface of the bent portion, i.e. the absorbent composite material is bonded to itself, or to an external surface, then the absorbent composite material is bonded to a liquid permeable sheet, a liquid impermeable sheet, or to another element.

The absorbent composite material may be bent separately or together with other elements. When the absorbent composite material is folded together with other elements, it is preferable that these are sheet materials.

Adhesives used in products for absorbing body fluids

Preferably, the adhesive is applied by a line in the direction of the product length, in other words, along the longest dimension, between the liquid permeable sheet and / or the liquid impermeable sheet and the absorbent composite material. Between the absorbent composite material and the liquid-permeable sheet and / or liquid-impermeable sheet, another sheet material may be located. In this case, the adhesive can be applied on the absorbent composite material itself, or on another sheet, or on a liquid permeable sheet and / or liquid impermeable sheet. In accordance with the present invention, the absorbent composite material has an unchanged sheet shape, the probability of its displacement inside the product for absorption of body fluids during use is small, thus ensuring a stable distribution and absorption of body fluids. The applied glue acts as a barrier to body fluids and, thereby, regulates the flow of this fluid and directs it, mainly along the longer dimension of the product to absorb body fluids. Typically, an article for absorbing body fluids has a pronounced length and width, and if the liquids are distributed mainly in the length direction, the efficiency of using the absorbent composite material is increased, and the likelihood of leakage of liquids in the width direction is reduced.

The properties of the adhesive used in the context of the present invention are not particularly limited; it can be liquid or solid. A single glue or a combination of two or more may be used. The type of glue also does not have certain restrictions, its examples include soluble glue, water dispersion glue, hot melt adhesive, composite glue, etc., namely adhesives based on polyurea, polymelanin, polyphenol, resorcinol, alpha-olefins, water-soluble polymer isocyanates, emulsions of polyvinyl acetate acrylic emulsion, chloroprene rubber, nitrile rubber, styrene butadiene rubber, natural rubber, epoxy resins, cyanoacrylate, polyurethane, polymethylmethacrylate, denatured organosilicon polymers, and aerobic adhesives, inorganic adhesives, paste, etc. Because hydrophilic adhesives are easily dispersible, which makes it difficult to control the bonding surface, it is preferable to use hydrophobic adhesives. To simplify the manufacturing process, it is preferable to use hot melt adhesive. Hot glue is any glue that is solid at room temperature, melts and spreads when heated, and when cooled it hardens and sticks; specific examples are adhesives containing, as main components, a copolymer of ethylene and vinyl acetate, polyamide, polyester, atactic polypropylene, thermoplastic elastomers and the like; rosin, coumaron-indene resin, etc., as well as waxes, antioxidants, inorganic fillers, plasticizers, etc. are used as tackifiers.

The amount of glue can be any that provides bonding. The amount of adhesive per unit length is preferably from 0.000001 to 0.1 g / cm, more preferably from 0.00001 to 0.01 g / cm, even more preferably from 0.00003 to 0.0045 g / cm. The amount of adhesive applied per unit area of the absorbent composite material is preferably from 0.2 to 1000 g / m ² , more preferably from 2.0 to 100 g / m ² . If too much glue is applied to the absorbent composite, it will prevent the swelling of the water-absorbing resin, reducing the absorption capacity, and damage the texture. On the other hand, in terms of adhesive strength, it is undesirable to apply little glue.

In accordance with the present invention, the adhesive can be applied in the form of one of the widely used patterns, such as winding lines, dots, vertical stripes, etc. If a measurement with a longer length, defined as a longitudinal direction, and a measurement with a shorter length, defined as a transverse direction, are distinguished from a product for absorbing body fluids or an absorbing composite material, it is preferable to apply glue so that the fluid flow is directed mainly in the longitudinal and not in the transverse direction in which leaks are most likely to reduce leaks. Examples of the shape and distinguishable directions of the absorbent composite material are shown in FIG. 4, where the arrows indicate the longitudinal direction, however, these examples are not restrictive. It is desirable to apply the adhesive in the form of a pattern that extends in the longitudinal direction and thus forms a barrier, which is a way of organizing a fluid flow mainly in the longitudinal direction. Since when, spreading out, the liquid reaches the glue, it cannot flow through it, the flow direction changes in accordance with the glue application pattern. In accordance with the present invention, an adhesive deposition pattern contributing to a predominant deviation of the flow in the direction of the length rather than the width of the product are longitudinal, spaced apart lines. Suitable examples of glue application patterns are shown in FIG. 13, however, they are not restrictive. In FIG. 13A shows a linear application of glue in the longitudinal direction. Each of the lines may be straight or curved, as in FIG. 13B. The lines may be continuous or short lines, as in FIG. 13C and D, or formed by a bitmap, as in FIG. 13E and F. Preferably, at least 60%, more preferably at least 80% of each line is an angle of up to 45 ° with a longitudinal direction. 60% or 80% means the total fraction of the lengths of straight lines making an angle of up to 45 ° with the longitudinal direction, relative to the total length of all lines. If the lines are curved, the total vector of these lines is preferably an angle of up to 45 ° with a straight line running in the longitudinal direction. The distance between the lines is preferably from 0.001 to 10 cm, more preferably from 0.01 to 5 cm, even more preferably from 0.1 to 2 cm. A spiral pattern in the longitudinal direction is also preferred, as shown in FIG. 13G. The vector of the spiral pattern is preferably an angle of up to 45 ° with a longitudinal direction. The vectors of each of the spiral lines are spaced, preferably from 0.001 to 10 cm, more preferably from 0.01 to 5 cm, even more preferably from 0.1 to 2 cm. Both one pattern and a combination can be used. several drawings, as shown in FIG. 13H. A pattern of intersecting lines can also be used, as in FIG. 13I. in this case, preferably at least 60%, more preferably at least 80% of all adhesive lines are spaced at intervals of 0.001 to 10 cm.

Assessment of the characteristics of the product for the absorption of body fluids

Evaluation of re-wetting and fluid drainage range

A wooden board of sufficient width is placed on the laboratory table, on which a straightened, wrinkle-free product for absorbing body fluids is fastened to the four corners of the buttons. A cylindrical tube with a diameter of 60 mm and a weight of 53.5 g was placed in the center of the absorbent composite material, 80 g of saline solution was heated to a temperature of 37 ° C and poured dropwise through the tube into the center of the absorbent composite material at a rate of 7 to 8 ml / s. When the saline solution is no longer visible on the upper surface of the top sheet, the tube is removed. 5 minutes after the start of dripping, measure the distance by which the fluid has moved in the longitudinal direction, the value of which is taken as the range of fluid discharge.

1 minute after the start of dripping, a square of 10 cm cut from Advantec No. 2 filter paper with a diameter of 150 mm is applied to the place where dripping was made, so that the total weight is about 90 g, and a load of 3 is immediately applied to this filter paper 5 kg. 3 minutes after application of the load, it is removed, filter paper is removed from the product and weighed. The value by which the weight of the filter paper has increased compared to the initial one is taken as the first rewet amount.

9 minutes after the start of dripping, the cylinder is returned to the same place. 10 minutes after the start of dripping, another 80 g of saline is poured dropwise and the same steps are repeated as in the first stage. The value by which the weight of the filter paper increased as a result is taken as the second rewet amount.

After 19 minutes after the start of dripping, the cylinder is returned to the same place. 20 minutes after the start of the first drip, another 80 g of saline is poured dropwise and the same steps are repeated. The value by which the weight of the filter paper increased as a result of these actions is taken as the third rewet value.

The amount of re-wetting is an indicator of the sensation of moisture during use of the product to absorb body fluids. If this value is large, the skin will be wet and the product unpleasant to wear. In order for the surface of the product to remain dry and cause a comfortable feeling, the re-wetting value should preferably be as small as possible. The repeated wetting values during multiple measurements reflect the sensations of the product for absorption of body fluids during continuous wear and repeated absorption of body fluids. The larger the second and third rewet values, the more comfortable this product is when worn continuously. The first rewet amount is preferably not more than 30 g, more preferably no more than 20 g, even more preferably no more than 10 g and even more preferably no more than 3 g. The second rewet amount is preferably no more than 40 g, more preferably no more than 30 g, even more preferably no more than 25 g and even more preferably no more than 20 g. The third re-wetting amount is preferably no more than 50 g, more preferably no more than 45 g, still more preferably not its 40 g, and still more preferably not more than 30 g.

Liquid discharge range means the distance in a given area of the absorbent composite material at which the liquid was absorbed, and the greater the liquid discharge range, the higher the efficiency of using the absorbent composite material. If the efficiency of using the absorbent composite material is high, then the desired absorption capacity can be achieved with a small amount of absorbent composite material and corresponding resource savings. If the liquid is diverted over a long distance, the absorbent layer after absorption is thin, and the probability of the bias of the absorbent composite material decreases, and the absorbent composite material becomes more comfortable to wear. The liquid discharge range is preferably at least 200 mm, more preferably at least 240 mm, even more preferably at least 270 mm, or even more preferably at least 300 mm.

Estimation of longitudinal distribution and distribution area

A wooden board of sufficient width is placed on the laboratory table, on which a straightened, wrinkle-free product for absorbing body fluids is fastened to the four corners of the buttons. A 50 cm ³ saline solution is continuously poured dropwise onto the center of the absorbent composite material at a speed of 1 ml / s. 2 minutes after completion of the drip, measure the length and width of the area over which the liquid was distributed. The longitudinal distribution is calculated according to the formula 11, and the distribution area is calculated according to the formula 12.

Longitudinal distribution = length of the distribution section in the longitudinal direction (cm) / length of the distribution section in the transverse direction (cm) (formula 11)

Distribution area = length of the distribution area in the longitudinal direction (cm) x length of the distribution area in the transverse direction (cm) (formula 12)

Typically, leaks in an article for absorbing body fluids are more likely in the transverse direction, in which the article is generally smaller. Preferably, the magnitude of the longitudinal distribution is large, since then the fluid flow will be easier to move in the longitudinal direction, and the likelihood of leaks will be reduced. A high longitudinal distribution is also desirable from the point of view of increasing the efficiency of use of the absorbent composite material. The longitudinal distribution is preferably at least 1.4, more preferably at least 1.7, even more preferably at least 2.0, or even more preferably at least 2.5 . In an absorbent composite material having a high ability to distribute liquid, this liquid can move until it reaches the side edge. Leakage usually does not occur immediately after the liquid reaches this edge, or it is prevented by the use of wings or the like. However, it is preferable that the distribution range in the transverse direction is less than the width of the product, since in the case of further addition of large quantities of liquid, leakage is possible.

Distribution area is an indicator of the ability of a given product to distribute liquid. To increase the efficiency of use of the absorbent composite material, it is preferable to use an absorbent composite material with a higher distribution area. With a constant amount of liquid to be absorbed, the absorbing composite material with a larger distribution area during the absorption process changes less in thickness and is more stable, since the larger the distribution area, the smaller the amount of liquid that must be absorbed by a surface unit. In addition, if there is little change in the thickness of the absorbent composite material, the hygiene product is comfortable to wear, as it does not cause the user to feel pressure. The size of the distribution area is preferably at least 150 cm ² , more preferably at least 200 cm ² , even more preferably at least 250 cm ^2, or even more preferably at least 300 cm ² .

Leak Assessment

In accordance with the present invention, the quantitative parameters of leaks are determined as follows. The center of the absorbent composite material included in the product for absorbing body fluids is marked with a cross about 1 cm in size. The absorbent composite material is fixed with buttons on a horizontal board above a line parallel to its short measurement through the center, as shown in FIG. 14. If the material has wings, etc. elements, they are also fixed so that the edges of the absorbent composite material are top views. Then, as shown in FIG. 15, insert the plastic panel and fasten the product with tape so that at the fixation point it forms an angle of 30 °. In this case, the absorbent composite material is straightened and does not form wrinkles.

A saline solution stained with food coloring in red is poured dropwise at a rate of 0.1 ml / s at the point marked with a cross. The amount of liquid poured by the time when the liquid being distributed begins to extend beyond the edges of the absorbent composite material is taken as the amount causing leakage.

The amount of leakage causing liquid is preferably at least 100 ml, more preferably at least 120 ml, even more preferably at least 135 ml, or even more preferably at least 150 ml. The amount of liquid that causes leakage can be increased by increasing the thickness and weight of the absorbent composite material, however, the product itself should preferably be thin and light. Therefore, in accordance with the present invention, an indicator of leakage resistance per unit area is the leakage coefficient, determined by formula 13 based on the amount of liquid that causes leakage, the weight of the absorbent composite material and its area.

Leakage coefficient = amount of liquid causing leakage (ml) / (weight of absorbent composite material (g) / area of absorbent composite material (cm ² )) (formula 13)

The weight and area of the absorbent composite material is determined in relation to the absorbent composite material as a whole. For absorbent composite materials with the same weight and area, the greater the leakage rate, the higher the resistance to leakage. The leakage rate is preferably at least 1000, more preferably at least 2000, even more preferably at least 3000, or even more preferably at least 4000. Preferably, the absorbent composite has a coefficient leakage, corresponding to the specified range, and was characterized by the amount of liquid causing the leak, lying in the range indicated above.

Examples

The following are specific examples of the implementation of the present invention, as well as comparative examples; however, the present invention is not limited to the examples given.

Production 1

Acrylic acid, a reagent of a certain quality produced by Wako Pure Chemical, was purified by distillation before use. 100 g of this acrylic acid was dissolved in 91.02 g of water. The aqueous solution was cooled in an ice bath and then maintained at a temperature of 30 ° C or less, gradually adding 117.94 g of a 25% by weight aqueous solution of ammonium and stirring until a 40% by weight aqueous solution of ammonium acrylate was obtained (degree of neutralization 100%).

90 g of a 40% by weight aqueous solution of ammonium acrylate and 0.0187 g of N, N'-methylene-bis-acrylamide were placed in a 300 ml detachable flask. The flask was immersed in a water thermostat, maintaining the temperature of the liquid at 30 ° C. To create a nitrogen atmosphere in the reaction system, oxygen was removed from the water thermostat by sparging with nitrogen gas. Then, using a syringe, 0.43 g of a 42% by weight aqueous glycerol solution was added, the mixture was thoroughly mixed; 0.0917 g of a 30% by weight aqueous solution of hydrogen peroxide and 0.0415 g of rongalite, each dissolved in 1 g of water, were added to initiate polymerization. 5 minutes after the start of the reaction, the temperature inside the flask was increased from the initial, 30 ° C, to 100 ° C. The mixture was then heated for 3 hours in a water thermostat so that the internal temperature was 70 ° C. After that, the gel was removed from the detachable flask, coarsely ground, and dried at 100 ° C for 4 hours in an inert atmosphere furnace. After drying, it was crushed using a homogenizer and subjected to classification by sieving into portions with a particle size of less than 106 microns, from 106 to 212 microns, from 212 to 300 microns, from 300 to 425 microns, from 425 to 500 microns, from 500 to 600 microns , from 600 to 710 microns, from 710 to 850 microns, from 850 to 1200 microns, from 1200 to 1400 microns, from 1400 microns to 1700 microns, from 1700 to 2500 microns, from 2500 to 3000 microns and more than 3000 microns. These particles were used as particles of water-absorbing resin 1. The surface strength of these resin particles was 0.5 N. The total concentration of ammonium salts was 96%, the salt concentration at the surface was 90%, and the salt concentration at the center of the particles was 97%.

Production 2

The water-absorbing resin particles obtained as described in Production 1 were heat-treated for 10 minutes in an inert atmosphere furnace at 180 ° C and used as water-absorbing resin particles 2. The surface strength of these resin particles was 2.7 N. The total concentration of ammonium salts was 70%, the salt concentration at the surface was 30%, and the salt concentration in the center of the particles was 95%.

Production 3

81.73 g of acrylic acid, which is a reagent of a certain quality produced by Wako Pure Chemical, 185.71 g of water and 31.78 g of sodium hydroxide were slowly added to a 300 ml flask with constant cooling, so that the temperature of the liquid did not exceed 30 ° C ( salt concentration of 70%). 90 g of this monomer solution and 0.0561 g of N, N'-methylene-bis-acrylamide were added to a 300 ml detachable flask. The flask was immersed in a water thermostat, maintaining the temperature of the liquid at 30 ° C. To create a nitrogen atmosphere in the reaction system, oxygen was removed from the water thermostat by sparging with nitrogen gas. Then, 0.0826 g of 30% by weight and 0.0518 g of rongalite were added to initiate polymerization, each was dissolved in 1 g of water. 10 minutes after the start of the reaction, the temperature inside the flask was increased from the initial, 30 ° C, to 70 ° C. 5 minutes after this, the temperature in the flask was increased to a maximum and the solution in a water thermostat was heated for 3 hours so that the internal temperature was 75 ° C. After a predetermined time, the gel was removed from the detachable flask, coarsely ground and dried at 100 ° C. for 4 hours in an inert atmosphere furnace. After drying, it was crushed using a homogenizer and subjected to classification by sieving into portions with a particle size of less than 106 microns, from 106 to 212 microns, from 212 to 300 microns, from 300 to 425 microns, from 425 to 500 microns, from 500 to 600 microns , from 600 to 710 microns, from 710 to 850 microns, from 850 to 1200 microns, from 1200 to 1400 microns, from 1400 microns to 1700 microns, from 1700 to 2500 microns, from 2500 to 3000 microns and more than 3000 microns. These particles were used as particles of water-absorbing resin 3. The surface strength of these resin particles was 0.9 N.

Production 4

A mixture of 0.6 g of isopropyl alcohol, 0.02 g of glycerol and 0.06 g of water was prepared and it was evenly distributed on 2 g of particles of water-absorbing resin 2, obtained as described in Production 3. These particles were kept for 10 min at a temperature 180 ° C in an inert atmosphere furnace and was used as particles of water-absorbing resin 4. The surface strength of these resin particles was 5.9 N.

Production 5

81.73 g of acrylic acid, which is a reagent of a certain quality produced by Wako Pure Chemical, 185.71 g of water and 21.8 g of sodium hydroxide were slowly added to a 300 ml flask with constant cooling of the flask with ice, so that the liquid temperature did not exceed 30 ° C (salt concentration 48%). 90 g of this monomer solution and 0.0561 g of n, n'-methylene-bis-acrylamide were added to a 300 ml detachable flask. The flask was immersed in a water thermostat, maintaining the temperature of the liquid at 30 ° C. To create a nitrogen atmosphere in the reaction system, oxygen was removed from the water thermostat by sparging with nitrogen gas. Then, to initiate the polymerization, 0.0826 g of a 30% by weight aqueous solution of hydrogen peroxide and 0.0518 g of rongalite were added, each was dissolved in 1 g of water. After 10 minutes, the temperature inside the flask was increased from the initial, 30 ° C, to 70 ° C. 5 minutes after this, the temperature in the flask was increased to a maximum and the solution in a water thermostat was heated for 3 hours so that the internal temperature was 75 ° C. After a predetermined time, the gel was removed from the detachable flask, coarsely ground and dried at 100 ° C. for 4 hours in an inert atmosphere furnace. After drying, it was crushed using a homogenizer and subjected to classification by sieving into portions with a particle size of less than 106 microns, from 106 to 212 microns, from 212 to 300 microns, from 300 to 425 microns, from 425 to 500 microns, from 500 to 600 microns , from 600 to 710 microns, from 710 to 850 microns, from 850 to 1200 microns, from 1200 to 1400 microns, from 1400 microns to 1700 microns, from 1700 to 2500 microns, from 2500 to 3000 microns and more than 3000 microns. These particles were used as particles of water-absorbing resin 5. The surface strength of these resin particles was 1.1 N.

Production 6

A mixture of 0.6 g of isopropyl alcohol, 0.02 g of glycerol and 0.06 g of water was prepared and evenly distributed on 2 g of particles of water-absorbing resin 5, obtained as described in Production 5. These particles were kept for 10 min at a temperature 180 ° C in an inert atmosphere furnace and was used as water-absorbing resin particles 6. The surface strength of these resin particles was 6 N.

Production 7

Acrylic acid, a reagent of a certain quality produced by Wako Pure Chemical, was purified by distillation before use. 753 g of this purified acrylic acid was cooled in an ice bath and then, while maintaining the liquid temperature at 30 ° C or less, 625 g of a 25% by weight aqueous solution of ammonia, which is a reagent of a certain quality, produced by Wako Pure, was gradually added to it with stirring Chemical, to obtain 66% by weight of an aqueous solution of ammonium acrylate (degree of neutralization of 100%). 0.0395 g of N, N'-methylene-bis-acrylamide dissolved in 1 g of water was added to the solution and dissolved with stirring, the mixture was deoxygenated by sparging with nitrogen gas.

4.3 L of cyclohexane and 7.8785 g of sorbitan monostearate as a surfactant were placed in a 12 L autoclave with a nitrogen atmosphere already created in it and dissolved with stirring at room temperature, the reaction system was deoxygenated at a pressure of 65 kPa. The temperature of the reaction system was increased, while maintaining a vacuum, to an internal temperature of 60 ° C. An aqueous solution of 0.7186 g of ammonium persulfate dissolved in 50 g of water was added to the described aqueous solution of ammonium acrylate. After increasing the internal temperature of the reaction system to 60 ° C, a prepared aqueous solution of ammonium acrylate was introduced into it and suspended by stirring at a speed of 120 rpm in a stream of nitrogen. Polymerization was initiated in the reaction system at 65 kPa and an internal temperature of 60 ° C. and stirred at a speed of 120 rpm for 2 hours to obtain an emulsion containing a wet gel. Normal pressure inside the reaction system was restored with nitrogen, the system was compacted and heated to an internal temperature of 80 ° C, the stirrer speed was set at 400 rpm and a mixed solution of 108.8 g of ethanol manufactured by Wako Pure Chemical and 8.35 g was introduced over 15 minutes glycerin. The pressure in the system was increased with nitrogen, the internal temperature was increased to 110 ° C, and stirring was continued for another 30 minutes. Then the pressure was reduced to normal, and the resulting wet gel was washed three times with 2 liters of cyclohexane at 40 ° C.

The wet gel was separated by filtration and dried at 70 ° C under full vacuum, and then, for 6 hours, in an inert oven at 70 ° C. After drying, the gel was coarsely crushed using a homogenizer and subjected to classification by sieving into portions with a particle size of less than 106 microns, from 106 to 212 microns, from 212 to 300 microns, from 300 to 425 microns, from 425 to 500 microns, from 500 to 600 microns, from 600 to 710 microns, from 710 to 850 microns, from 850 to 1200 microns, from 1200 to 1400 microns, from 1400 microns to 1700 microns, from 1700 to 2500 microns, from 2500 to 3000 microns and more than 3000 microns. These particles were used as particles of water-absorbing resin 7. The absorption capacity of these resin particles was 70 g / g and the surface strength was 0.4 N. The total concentration of ammonium salts was 95%, the salt concentration at the surface was 88%, and the salt concentration in the center of the particles - 97%.

Particles of water-absorbing resin 7, obtained as described in section Production 7, were subjected to heat treatment for 10 min in an inert oven at 180 ° C. The conditions for this operation are the same as for heat treatment in order to form a composite material based on the base material in the following examples. As a result, the surface strength of the particles of the water-absorbing resin was 2.5 N at a total concentration of ammonium salts of 70%, a salt concentration at the surface of 32%, and a salt concentration in the center of the particles of 94%.

Production 8

The same actions were performed as described in Production 7, except that the mixing speed during the polymerization was set not to 120, but to 400 rpm. The resulting particles are particles of water-absorbing resin 8. The absorption capacity of these resin particles was 80 g / g and the surface strength was 0.4 N. The total concentration of ammonium salts was 95%, the salt concentration at the surface was 87%, and the salt concentration in the center particles - 97%.

Particles of water-absorbing resin 8, obtained as described in Production 8, were heat-treated for 10 minutes in an inert atmosphere furnace at 180 ° C. The conditions for this operation are the same as for heat treatment in order to form a composite material based on the base material in the following examples. As a result, the surface strength of the particles of the water-absorbing resin was 2.2 N at a total concentration of ammonium salts of 68%, a salt concentration at the surface of 33%, and a salt concentration in the center of the particles of 93%.

Production 9

Prepared acrylic acid, which is a reagent of a certain quality manufactured by Wako Pure Chemical. 2557.8 g of this acrylic acid reagent was dissolved in 2087.3 g of water, the aqueous solution was cooled in an ice bath and then, while maintaining the liquid temperature at 30 ° C or less, 3507.0 g of 40.5% was gradually added to it with stirring. by weight aqueous solution of NaOH to obtain a 40% by weight aqueous solution of sodium acrylate.

1733.0 g of the thus obtained aqueous solution of sodium acrylate was dissolved in 341.5 g of water. To this aqueous solution of sodium acrylate was added 227.7 g of acrylic acid to form 2302.2 g of a 40% by weight aqueous solution with a ratio of sodium acrylate / acrylic acid = 70/30. 2.5 g of N, N'-methylene-bis-acrylamide was added and dissolved to it as a crosslinking agent, the mixture was deoxygenated by sparging with nitrogen gas.

4.3 L of cyclohexane and 7.8785 g of sorbitan monostearate as a surfactant were placed in a 12 L autoclave with a nitrogen atmosphere already created in it and dissolved with stirring at room temperature, the reaction system was deoxygenated at a pressure of 65 kPa. The temperature of the reaction system was increased, while maintaining a vacuum, to an internal temperature of 60 ° C. An aqueous solution of 0.7186 g of ammonium persulfate dissolved in 50 g of water was added to the described aqueous solution of sodium acrylate. After increasing the internal temperature of the reaction system to 60 ° C, a prepared aqueous solution of sodium acrylate was introduced into it and suspended by stirring at a speed of 400 rpm in a stream of nitrogen. Polymerization was initiated in the reaction system at 65 kPa and an internal temperature of 60 ° C. and stirred at a speed of 400 rpm for 2 hours to obtain an emulsion containing a wet gel. Normal pressure inside the reaction system was restored with nitrogen, the system was compacted and heated to an internal temperature of 80 ° C, the stirrer speed was set to 400 rpm and a mixed solution of 108.8 g of ethanol manufactured by Wako Pure Chemical and 4.2 g was introduced over 15 minutes glycerin. The pressure in the system was increased with nitrogen, the internal temperature was increased to 110 ° C, and stirring was continued for another 30 minutes. Then the pressure was reduced to normal, and the resulting wet gel was washed three times with 2 liters of cyclohexane at 40 ° C.

The wet gel was separated by filtration and dried at 70 ° C under full vacuum. After drying, the gel was crushed using a homogenizer and subjected to classification by sieving into portions with a particle size of less than 106 microns, from 106 to 212 microns, from 212 to 300 microns, from 300 to 425 microns, from 425 to 500 microns, from 500 to 600 microns , from 600 to 710 microns, from 710 to 850 microns, from 850 to 1200 microns, from 1200 to 1400 microns, from 1400 microns to 1700 microns, from 1700 to 2500 microns, from 2500 to 3000 microns and more than 3000 microns. These particles were used as particles of water-absorbing resin 9. The absorption capacity of these resin particles was 55 g / g and the surface strength was 1.2 N.

Production 10

Acrylic acid, a reagent of a certain quality produced by Wako Pure Chemical, was purified by distillation before use. 753 g of this purified acrylic acid was cooled in an ice bath and then, while maintaining the liquid temperature at 30 ° C or less, 625 g of a 25% by weight aqueous solution of ammonia, which is a reagent of a certain quality, produced by Wako Pure, was gradually added to it with stirring Chemical, to obtain 66% by weight of an aqueous solution of ammonium acrylate (degree of neutralization of 100%). The mixture was deoxygenated by sparging with nitrogen gas.

4.3 L of cyclohexane and 7.53 g of sorbitan monolaurate as a surfactant were placed in a 12 L autoclave with a nitrogen atmosphere already created in it and dissolved with stirring at room temperature, the reaction system was deoxygenated at a pressure of 30 kPa. The temperature of the reaction system was increased, while maintaining a vacuum, to an internal temperature of 40 ° C. An aqueous solution of 0.7699 g of ammonium persulfate dissolved in 50 g of water was added to the described aqueous solution of ammonium acrylate. After increasing the internal temperature of the reaction system to 40 ° C, a prepared aqueous solution of ammonium acrylate was introduced into it and suspended by stirring at a speed of 400 rpm in a stream of nitrogen. In the reaction system at 30 kPa and an internal temperature of 40 ° C, polymerization was initiated and stirring was provided at a speed of 400 rpm for 2 hours to obtain an emulsion containing a wet gel. Then, normal pressure was restored inside the reaction system, and the resulting wet gel was washed three times with 2 liters of cyclohexane at 40 ° C.

The wet gel was separated by filtration and dried at 70 ° C under full vacuum. After drying, the gel was crushed using a homogenizer and subjected to classification by sieving into portions with a particle size of less than 106 microns, from 106 to 212 microns, from 212 to 300 microns, from 300 to 425 microns, from 425 to 500 microns, from 500 to 600 microns , from 600 to 710 microns, from 710 to 850 microns, from 850 to 1200 microns, from 1200 to 1400 microns, from 1400 microns to 1700 microns, from 1700 to 2500 microns, from 2500 to 3000 microns and more than 3000 microns. These particles were used as particles of water-absorbing resin 10. The absorption capacity of these resin particles was 80 g / g and the surface strength was 0.6 N. The total concentration of ammonium salts was 97%, the salt concentration at the surface was 91%, and the salt concentration in the center of the particles - 98%.

Particles of water-absorbing resin 10, obtained as described in Production 10, were heat-treated for 10 minutes in an inert atmosphere furnace at 180 ° C. The conditions for this operation are the same as for heat treatment in order to form a composite material based on the base material in the following examples. As a result, the surface strength of the particles of the water-absorbing resin was 2.8 N with a total concentration of ammonium salts of 70%, a salt concentration at the surface of 29%, and a salt concentration in the center of the particles of 95%.

Production 11

Prepared acrylic acid, which is a reagent of a certain quality manufactured by Wako Pure Chemical. 2557.8 g of this acrylic acid reagent was dissolved in 2087.3 g of water, the aqueous solution was cooled in an ice bath and then, while maintaining the liquid temperature at 30 ° C or less, 3507.0 g of 40.5% was gradually added to it with stirring. by weight aqueous solution of NaOH to obtain a 40% by weight aqueous solution of sodium acrylate.

1733.0 g of the thus obtained aqueous solution of sodium acrylate was dissolved in 341.5 g of water. To this aqueous solution of sodium acrylate was added 227.7 g of acrylic acid to form 2302.2 g of a 40% by weight aqueous solution with a ratio of sodium acrylate / acrylic acid = 70/30. 2.5 g of N, N'-methylene-bis-acrylamide was added and dissolved to it as a crosslinking agent, the mixture was deoxygenated by sparging with nitrogen gas.

4.3 L of cyclohexane and 7.8785 g of sorbitan monostearate as a surfactant were placed in a 12 L autoclave with a nitrogen atmosphere already created in it and dissolved with stirring at room temperature, the reaction system was deoxygenated at a pressure of 65 kPa. The temperature of the reaction system was increased, while maintaining a vacuum, to an internal temperature of 60 ° C. An aqueous solution of 0.7186 g of ammonium persulfate dissolved in 50 g of water was added to the described aqueous solution of sodium acrylate. After increasing the internal temperature of the reaction system to 60 ° C, a prepared aqueous solution of sodium acrylate was introduced into it and suspended by stirring at a speed of 400 rpm in a stream of nitrogen. Polymerization was initiated in the reaction system at 65 kPa and an internal temperature of 60 ° C. and stirred at a speed of 400 rpm for 2 hours to obtain an emulsion containing a wet gel. Normal pressure inside the reaction system was restored with nitrogen, the system was compacted and heated to an internal temperature of 80 ° C, the stirrer speed was set at 400 rpm and 108.8 g of ethanol manufactured by Wako Pure Chemical was introduced over 15 minutes. The pressure in the system was increased with nitrogen, the internal temperature was increased to 110 ° C, and stirring was continued for another 30 minutes. Then the pressure was reduced to normal, and the resulting wet gel was washed three times with 2 liters of cyclohexane at 40 ° C.

The wet gel was separated by filtration and dried at 70 ° C under full vacuum. After drying, the gel was crushed using a homogenizer and subjected to classification by sieving into portions with a particle size of less than 106 microns, from 106 to 212 microns, from 212 to 300 microns, from 300 to 425 microns, from 425 to 500 microns, from 500 to 600 microns , from 600 to 710 microns, from 710 to 850 microns, from 850 to 1200 microns, from 1200 to 1400 microns, from 1400 microns to 1700 microns, from 1700 to 2500 microns, from 2500 to 3000 microns and more than 3000 microns. These particles were used as particles of water-absorbing resin 11. The absorption capacity of these resin particles was 57 g / g, and the surface strength was 1.1 N.

The properties of the particles of water-absorbing resin 1-11 obtained as described in the sections Production 1-11 are shown in table 1.

Table 1 The average absorption capacity, g / g Absorption capacity under pressure, g / g The number of unreacted monomers (parts / million) Particles of water-absorbing resin 1 76 28 170 Particles of water-absorbing resin 2 83 35 <20 Particles of water-absorbing resin 3 61 26 200 Particles of water-absorbing resin 4 54 21.6 160 Particles of water-absorbing resin 5 53 23 190 Particles of water-absorbing resin 6 43 12.3 160 Particles of water-absorbing resin 7 70 <20 Particles of water-absorbing resin 8 80 <20 Particles of water-absorbing resin 9 55 <20 Particles of water-absorbing resin 10 80 <20 Particles of water-absorbing resin 11 57 <20 Particles of water-absorbing resin 12 76 28 170 Particles of water-absorbing resin 13 76 28 170

Example 1

From Bemliese® material (material properties are presented in table 2) manufactured by Asahi Kasei Fibers Corp. cut a circular element with a diameter of 59.5 mm, the weight of which was 0.0796 g. Bemliese® is a non-woven fabric made from 100% continuous cellulosic fibers and, like a non-woven cellulosic fabric, has excellent absorption properties. Due to the fact that the material is made of continuous fibers, it is quite durable after absorption of water and has a good ability to distribute liquid.

0.164 g of Particles of water-absorbing resin 1, obtained as described in Production 1 and having a particle size of from 850 to 1200 μm, were placed on a Teflon sheet with a diameter of 59.5 mm so that they were not laid tightly. This sheet was named Sheet 1. Another Teflon sheet prepared in the same way was called Sheet 2. Bemliese® was placed on Sheet 1 and 3 ml of water was sprayed with a spray gun. Sheet 1 was placed on Sheet 2 with the bottom side up, so that the Bemliese® was lying on the particles laid on Sheet 2. From above it was lightly pressed by hand and left for 1 min, then it was heated at 180 ° C for 10 min in an inert atmosphere furnace. The weight, measured immediately after heating, was 0.4061 g; the calculated weight ratio of the water-absorbing resin in the composite material was 80.4%. All particles of the water-absorbing resin were firmly bonded to Bemliese®; as a result of rubbing with a hand, none of the particles detached. Using a scanning electron microscope (JEOL JSM-5300), it was found that all particles are bonded to Bemliese® to incorporate fibers into the water-absorbing resin. In FIG. 16 shows an image of the adhesion geometry obtained with an electron microscope with a magnification of 150 × laterally at an angle rather than from above, from the particle side, which allows you to see the adhesion geometry. This composite material is given as Example 1.

In FIG. 16, in a portion within the oval, the water-absorbing resin is bonded to fibers. Particles of water-absorbing resin are visible in the upper right part of this section, and the fibers of the base material are visible in the lower left, they look dark, which indicates that they are involved inside the particles of water-absorbing resin.

Example 2

The experiment was carried out in the same manner as in Example 1, except that resin particles 7 of size 850 to 1200 μm were used, obtained as described in Production 7. The evaluation of the results is given in Table 3.

Example 3

The experiment was carried out in the same way as in Example 1, except that the resin particles 8 were used, ranging in size from 850 to 1200 microns, obtained as described in Production 8. The evaluation of the results is given in table 3.

Example 4

The experiment was carried out in the same way as in Example 1, except that the particles of resin 9 were used, ranging in size from 850 to 1200 microns, obtained as described in Production 9. The evaluation of the results is given in table 3.

Example 5

The experiment was carried out in the same way as in Example 1, except that resin particles 10 of size 850 to 1200 μm were used, obtained as described in Production 10. The evaluation of the results is given in table 3.

Example 6

The experiment was carried out in the same way as in Example 1, except that resin particles 11 of size 850 to 1200 μm were used, obtained as described in Production 11. The evaluation of the results is given in table 3.

Comparative Example 1

81.73 g of Acrylic Acid Reagent (which is a reagent of a certain quality produced by Wako Pure Chemical) 185.71 g of water and 31.78 g of sodium hydroxide were gradually introduced into a 300 ml flask with constant cooling with ice, so that the temperature of the liquid did not exceed 30 ° C (salt concentration 70%). 90 g of the monomer solution was poured into the atomizer in a chamber with a nitrogen atmosphere and 0.0561 g of N, N'-methylene-bis-acrylamide was added. The resulting aqueous solution was deoxygenated by sparging with nitrogen gas. 1 ml of a solution of 0.022 g of iron (III) chloride hexahydrate dissolved in 100 g of water, 1 ml of a 30% by weight hydrogen peroxide solution and a solution of 0.12 g of L-ascorbic acid in 1 ml of water were quickly added and mixed, the resulting mixture sprayed onto Spun Bond EltasCrimp® PC8020 manufactured by Asahi Kasei Fibers Corp. All the material obtained, including the nonwoven fabric, was heated to 60 ° C on a hot plate and polymerized for 1 hour, then the temperature was increased to 120 ° C and maintained for 30 minutes to complete the polymerization. The material was then vacuum dried at 100 ° C and the amount of unreacted monomers was measured, amounting to 1000 ppm or more.

Reference Example 2

Composite material was prepared in the same manner as in Example 1 using particles of water-absorbing resin 2 obtained as described in Production 2. Particles ranging in size from 850 to 1200 μm were used. Due to the low concentration of ammonium salts at the surface, 30%, only about 35% of the particles were bound to the base material. Particle occupancy was measured immediately after heating until the resin detached. Due to the fact that the proportion of bound particles was low, it was difficult to obtain stable characteristics. Evaluation of the results is given in table 3.

Reference Example 3

Composite material was prepared in the same manner as in Example 1 using particles of water-absorbing resin 6, obtained as described in section Production 6. Particles ranging in size from 850 to 1200 μm were used. Their surface strength was high, 6 N, and only about 25% of the particles were bound to the base material. Particle occupancy was measured immediately after heating until the resin detached. Evaluation of the results is given in table 3.

Reference Example 4

Composite material was prepared in the same manner as in Example 1, except that no water was added. Particle binding did not occur.

Example 7

Composite material was prepared in the same manner as in Example 1, except that 15 g of water was used. Since not all water evaporated after 10 minutes of heating, heating continued for another 10 minutes.

Example 8

A composite material was prepared in the same manner as in Example 1, except that the drying was carried out at 60 ° C for 5 hours.

Example 9

A composite material was prepared in the same manner as in Example 1, except that the drying temperature was 370 ° C. Due to the fact that the material may burn during overheating, the drying conditions were checked every few seconds and the heating was stopped when the material was dry.

The physical properties of the absorbent composite materials obtained in Examples 1-9 and in Comparative examples 2 and 3 are presented in table 3.

Example 10

The experiment was carried out in the same manner as in Example 1, except that resin particles 1 of size 500 to 600 μm were used, obtained as described in Production 1. The weight ratio of resin in the absorbent composite material was 67.6%. Evaluation of the results is given in table 4.

Example 11

The experiment was carried out in the same manner as in Example 1, except that resin particles 1 from 710 to 850 μm in size were used, obtained as described in Production 1. The weight ratio of resin in the absorbent composite was 72.6%. Evaluation of the results is given in table 4.

Example 12

The experiment was carried out in the same way as in Example 1, except that the base material was used viscose lace fabric (Spunlace) (its physical properties are shown in table 2), and the weight ratio of the resin in the absorbent composite material was 81.5% . Evaluation of the results is given in table 4.

Example 13

The experiment was carried out in the same manner as in Example 1, except that resin particles 1 of size 1700 to 2500 μm were used, obtained as described in Production 1. The weight ratio of resin in the absorbent composite was 89.2%. Evaluation of the results is given in table 4.

Example 14

The experiment was carried out in the same manner as in Example 1, except that resin particles 1 from 710 to 850 μm in size were used, obtained as described in Production 1. The weight ratio of resin in the absorbent composite was 72.8%. Evaluation of the results is given in table 4.

Example 15

The experiment was carried out as in Example 1, except that the weight ratio of resin in the absorbent composite material was 66.6%. Evaluation of the results is given in table 4.

Example 16

The experiment was carried out as in Example 8, except that the weight ratio of resin in the absorbent composite material was 71.6%. Evaluation of the results is given in table 4.

Example 17

The experiment was carried out in the same way as in Example 1, except that resin particles 7 ranging in size from 850 to 1200 μm were used, obtained as described in Production 7, the weight ratio of resin in the absorbent composite material was 80.0%, and as the base material was used viscose lace fabric (Spunlace). Evaluation of the results is given in table 4.

Reference Example 5

The experiment was carried out in the same manner as in Example 1, except that resin particles 1 from 300 to 425 μm in size were used, obtained as described in Production 1. The weight ratio of resin in the absorbent composite was 64%. Evaluation of the results is given in table 4.

The physical properties of the absorbent composite materials obtained in Examples 10-17 and in Comparative example 5 are presented in table 4.

Example 18

The composite material in Example 18 was prepared in the same manner as in Example 1, except for using a mixture of particles: 50% by weight. particles of water-absorbing resin 1 ranging in size from 850 to 1200 microns, obtained as described in Production 1, and 50% by weight. particles of water-absorbing resin 1 ranging in size from 100 to 300 microns, obtained as described in Production 1. 98% of the particles were in a bound state with the inclusion of fibers in the water-absorbing resin upon binding.

Example 19

The composite material in Example 19 was prepared in the same manner as in Example 1, except for using a mixture of particles: 30% by weight. particles of water-absorbing resin 1 ranging in size from 850 to 1200 microns, obtained as described in Production 1, and 70% by weight. particles of water-absorbing resin 1 ranging in size from 100 to 300 microns, obtained as described in Production 1. 98% of the particles were in a bound state with the inclusion of fibers in the water-absorbing resin upon binding.

Example 20

The composite material in Example 20 was prepared in the same manner as in Example 1, except for using a mixture of particles: 30% by weight. particles of water-absorbing resin 1 ranging in size from 850 to 1200 microns, obtained as described in the Production section 1, 20% by weight. particles of water-absorbing resin 1 with a size of 3000 μm or more, obtained as described in Production 1, and 50% by weight. particles of water-absorbing resin 1 ranging in size from 100 to 300 microns, obtained as described in Production 1. 98% of the particles were in a bound state with the inclusion of fibers in the water-absorbing resin upon binding.

Example 21

The composite material in Example 21 was prepared in the same way as in Example 1, except for the use of particles of water-absorbing resin 3 ranging in size from 850 μm to 1200 μm, obtained as described in Production 3. All particles were firmly bonded to the Bemliese® material with the inclusion of fibers into water-absorbing resin. Compared to the particles of water-absorbing resin 1 obtained as described in Production 1, the amount of liquid absorbed by this composite material was slightly less due to the lower absorption volume of these resin particles.

Example 22

The composite material in Example 22 was prepared in the same way as in Example 1, except for the use of particles of water-absorbing resin 4 ranging in size from 850 μm to 1200 μm, obtained as described in Production 4. The adhesion was slightly lower due to the higher surface strength of the particles , 67% of the particles were bound.

Example 23

The composite material in Example 23 was prepared in the same way as in Example 1, except that instead of using Bemliese® material, Spun Bond® nylon material (its physical properties are shown in Table 2) manufactured by Asahi Kasei Fibers. Particles ranging in size from 850 to 1200 microns were used. 92% of the particles were bound.

Example 24

The composite material in Example 24 was prepared in the same way as in Example 1, except for the use of Oji Kinocloth KS-40® material (its physical properties are shown in table 2) instead of Bemliese® material, manufactured by Oji Kinocloth. Oji Kinocloth is a nonwoven fabric made from dry pulp. Particles ranging in size from 850 to 1200 microns were used. All particles were in a bound state with the inclusion of fibers in the water-absorbing resin. Due to the low strength of the cellulose, the particles were easily separated with tweezers along with the cellulose fibers.

Example 25

The composite material in Example 25 was prepared in the same manner as in Example 1, except that instead of using Bemliese® material, PET Spunbond® (its physical properties are shown in Table 2) manufactured by Asahi Kasei Fibers. Particles ranging in size from 850 to 1200 microns were used. The adhesion was small, only 62% of the particles were in a bound state.

Example 26

The composite material in Example 26 was prepared in the same manner as in Example 1, except for using instead of the Bemliese® material the Spunbond Eltas® polypropylene material (its physical properties are shown in Table 2) manufactured by Asahi Kasei Fibers. Particles ranging in size from 850 to 1200 microns were used. The adhesion was small, only 51% of the particles were in a bound state.

Example 27

The composite material in Example 27 was prepared in the same way as in Example 1, except that instead of using Bemliese® material, single sheets of “Piason” toilet paper from Toyo Co. Particles ranging in size from 850 to 1200 microns were used. Since the strength of the paper in the wet state is low, it was easily torn during handling.

Example 27-2

The composite material in Example 27-2 was prepared in the same manner as in Example 1, except that the resin fraction was 94%, particles of water-absorbing resin 1 from 850 μm to 1200 μm in size were used, obtained as described in Production 1. 95% of the particles were bound. The absorbent resin particles were packed tightly. Some particles separated after absorption, as they were stacked on top of each other.

Reference example 1

Liquid permeability measurement of film wrapping products manufactured by Asahi Kasei Life & Living Co., Ltd. Water cannot pass through this film. It is not preferable to use a film that is absolutely impervious to water as a hygienic material; it can be used only on one side.

Reference Example 7

In Comparative Example 7, a mixture of pulp and water-absorbing resin taken from a Pampers Cotton Care® size M absorber from P&G Co., Ltd. was used. The water-absorbing resin was not associated with the pulp, which mass was fluffed and did not retain its shape. The weight ratio of the resin was not possible to measure by the method of the present invention. Due to the lack of base material, the area occupancy was also not measured.

Reference Example 8

From Rifure Anshin Pad® gaskets designed for 150 cm ³ absorption, Livedo Corporation separated the top and bottom sheets and removed the absorber. A circular element with a diameter of 59.5 mm was cut from its central part. In this case, the water-absorbing resin was bonded to the base material with glue and was not directly bonded to it. This case is given as Comparative Example 8.

Reference Example 9

Acrylic acid, a reagent of a certain quality produced by Wako Pure Chemical, was purified by distillation before use. 10 g of this acrylic acid reagent was dissolved in 91.02 g of water. The aqueous solution was cooled in an ice bath and then maintained at a temperature of 30 ° C or less, gradually adding 117.94 g of a 25% by weight aqueous solution of ammonium and stirring until a 40% by weight aqueous solution of ammonium acrylate was obtained .

A simple chamber with a nitrogen atmosphere was prepared and all subsequent operations were performed in this chamber. 90 g of a 40% by weight aqueous solution of ammonium acrylate and 0.0187 g of N, N'-methylene-bis-acrylamide were placed in a 300 ml flask. The aqueous solution was deoxygenated by sparging with nitrogen gas. The internal temperature at this time was 20 ° C. Then, using a syringe, 0.43 g of a 42% by weight aqueous glycerol solution was added, the mixture was thoroughly mixed; 0.0917 g of a 30% by weight aqueous solution of hydrogen peroxide and 0.0415 g of rongalite, each dissolved in 1 g of water, were added to initiate polymerization. After the internal temperature began to rise and exceeded 20 ° C, 50 g of the reaction mixture was poured onto 3 g of Bemliese® material laid on a tray and left for 3 hours. Then it was taken out of the chamber with a nitrogen atmosphere and dried at 100 ° C for 4 hours in an inert atmosphere furnace. The obtained absorbent composite material is given as Comparative Example 9. It turned out to be tough, it is difficult to cut and bend. Since it was difficult to measure its absorption capacity directly, initially, before the measurement, it was crushed in the same way as particles of water-absorbing resin, and was classified by sieving by sizes from 106 to 850 microns. It was not possible to measure the weight ratio of the resin and the area occupancy for this composite material since it was crushed.

Reference Example 10

A composite material was prepared in the same manner as in Example 1, except for the use of particles of water-absorbing resin 1 ranging in size from 850 μm to 1200 μm obtained as described in Production 1 with a resin weight ratio of 25%. This case is given as Comparative Example 10. All particles of the water-absorbing resin were in a bound state.

Reference Example 12

A composite material was prepared in the same manner as in Example 1, except for the use of particles of water-absorbing resin 1 ranging in size from 850 μm to 1200 μm obtained as described in Production 1 with a resin weight ratio of 55%. This case is given as Comparative Example 12. All particles of the water-absorbing resin were in a bound state.

The physical properties of absorbent composite materials (absorbers) obtained in Examples 18-27-2 and in Comparative examples 7-12 are presented in table 5.

Production 12

Particles of water-absorbing resin 12 were obtained in the same manner as described in Production 1, except that these particles were classified on sieves with mesh sizes of 106 μm, 212 μm, 300 μm, 425 μm, 500 μm, 600 μm, 710 μm, 850 μm, 1000 μm, 1180 μm, 1400 μm, 1700 μm and 2500 μm.

Production 13

Particles of water-absorbing resin 13 were obtained in the same manner as described in Production 3, except that these particles were classified on sieves with mesh sizes of 106 μm, 212 μm, 300 μm, 425 μm, 500 μm, 600 μm, 710 μm, 850 μm, 1000 μm, 1180 μm, 1400 μm, 1700 μm and 2500 μm.

Example 28

A 27 cm long and 8 cm wide piece was cut from Bemliese® manufactured by Asahi Kasei Fiber. Bemliese® is a non-woven fabric made from 100% continuous cellulosic fibers. As a cellulosic non-woven fabric, it has good absorption characteristics. Due to the fact that it is made of continuous fibers, the material is sufficiently strong in the wet state and has a high ability to distribute liquid. A piece 27 cm long and 8 cm wide was also cut out of Teflon® Teflon sheet and a line was drawn on it with a length of 25 cm and a width of 6 cm. Repeated this operation again. 1.5 g of the Particles of water-absorbing resin 12 remaining on a sieve with a mesh size of 1000 μm in the manufacture described in the Production 12 section, were evenly distributed within the drawn line using a sieve with a mesh size of 1180 μm. 1.5 g of resin particles remaining on a sieve with a mesh size of 212 μm were also evenly distributed using a sieve with a mesh size of 300 μm. 1.5 g of resin particles remaining on a sieve with a mesh size of 1000 μm, evenly distributed in the same way on another sheet. 1.2 g of water was sprayed onto a Bemliese® material using a spray gun, which was then placed on prepared sheets to adhere the resin to both of its surfaces. The material was dried for 10 minutes at 180 ° C in an inert atmosphere furnace, with a portion of the material on which there was no resin was pressed with a load to prevent shrinkage of the Bemliese® material. The resulting material was Example 28.

Examples 29-32

The composite material was obtained in the same manner as in Example 28, except for changing the size and number of particles of water-absorbing resin 12 used.

In Example 29, 1.5 g of resin particles remaining on a sieve with a mesh size of 500 μm were used on each side of the material.

In Example 30, 1.5 g of resin particles remaining on a sieve with a mesh size of 850 μm were used on each side of the material, and on the one hand, 1.5 g of resin particles remaining on a sieve with a mesh size of 212 μm were used.

In Example 31, 1.05 g of resin particles remaining on a sieve with a mesh size of 710 μm were used on each side of the material, and 2.4 g of resin particles remaining on a sieve with a mesh size of 300 μm were used on one side.

In Example 32, 1.05 g of resin particles remaining on a sieve with a mesh size of 710 μm were used on each side of the material, and 0.975 g of resin particles remaining on a sieve with a mesh size of 300 μm were used on one side.

Example 33

The composite material in Example 33 was prepared in the same way as in Example 28, except for using particles of water-absorbing resin 13 obtained as described in Production section 13. The amount of liquid absorbed by this composite material was slightly less, since the resin particles contained non-salt ammonia, and absorbed less than the particles of water-absorbing resin obtained as described in section Production 12. Some particles were separated from it after the manufacture of the material, since the concentration of salt on x surface was slightly less than the concentration of ammonium salts.

Example 34

The composite material in Example 34 was made in the same manner as in Example 28, except for the use of Asahi Kasei Fiber Nylon Spunbond® material instead of Bemliese® material. This material is given as Example 34.

Example 35

The composite material in Example 35 was made in the same manner as in Example 28, except for using Oji Kinocloth KS-40® material instead of Bemliese®. Oji Kinocloth is a nonwoven fabric made from dry pulp. Due to the low strength of the cellulose, the particles were easily separated with tweezers along with the cellulose fibers.

Example 36

The composite material in Example 36 was made in the same manner as in Example 28, except for the use of Asahi Kasei Fibers PET Spunbond® material instead of Bemliese® material. Traction was low.

Example 37

The composite material was made in the same way as in Example 28, except for changing the size and quantity of the particles of water-absorbing resin 7 obtained as described in Production 7.

In Example 37, 1.5 g of resin particles passed through a sieve with a mesh size of 1400 μm but remained on a sieve with a mesh size of 850 μm were used on each side of the material, and 1.5 g of resin particles passed through a sieve were used on one side with a mesh size of 300 microns, but remaining on a sieve with a mesh size of 212 microns.

Example 38

The composite material was made in the same way as in Example 28, except for changing the size of the used particles of water-absorbing resin 8, obtained as described in the Production section 8.

In Example 38, 1.5 g of resin particles passed through a sieve with a mesh size of 1400 μm but remained on a sieve with a mesh size of 850 μm were used on each side of the material, and 1.5 g of resin particles passing through a sieve were used on one side with a mesh size of 300 microns, but remaining on a sieve with a mesh size of 212 microns.

Example 39

The composite material was made in the same way as in Example 28, except for changing the size of the used particles of water-absorbing resin 7 and 8, obtained as described in sections Production 7 and 8.

In Example 39, 1.5 g of resin particles 7 were used on each side of the material, manufactured as described in Production 7 and passed through a sieve with a mesh size of 1400 μm, but remained on a sieve with a mesh size of 850 μm, and on one side - 1.5 g of resin particles 8, made as described in Production 8, and passed through a sieve with a mesh size of 300 μm, but remaining on a sieve with a mesh size of 212 μm.

The physical properties of the absorbent composite materials obtained in Examples 28-39 are presented in table 6.

Example 40

The apparatus shown in FIG. 17. On it (a) is a roll of fabric (base material) Bemliese® manufactured by Asahi Kasei Fiber 500 mm wide. The density of this tissue is 28 g / m ² . Water and gas pipelines are connected to the spray nozzle of the water sprayer (b). The amount of water sprayed is controlled by the pressure of the gas and water in the spray nozzle. A funnel is provided in the device for loading particles of water-absorbing resin (d1) (feed unit). Above the drum (e1), a gas blower (i1) is provided to blow off particles of water-absorbing resin supplied from the funnel (d1) and adhered to other parts of the drum than the wells. To dry the surface of the drum before it comes into contact with the particles, a blower (j1) is provided that supplies dry, warm air. The drum (e1) has a diameter of 500 mm and a width of 500 mm. The design of the holes located on the surface of the drum is shown in FIG. 18 and 19. FIG. 18 shows the relative position of the holes on the surface of the drum when viewed from above. Wells are arranged so that the distance between the centers of adjacent holes is approximately 3.1 mm. FIG. 19 is a cross section of the hole, which shows that it is hollow and directed from the surface of the drum inward, while the hole in the surface of the drum is a circle with a diameter of 1.5 mm and tapers to 0.7 mm at a depth of 0.8 in the direction of the inner parts of the drum, and then the diameter of the hole, equal to 0.7 mm, does not change throughout the depth of the hole.

The fabric (c) that has passed under the drum (e1) and to which resin particles (f) are attached to one side then passes between the rollers (l), which strengthen the bond between the resin particles and the fabric. The same equipment as described above in the case of a drum (e1), a loading funnel (d1), a gas blower (i1) and a blower (j1) is used respectively as a drum (e2), a loading funnel (d2), a gas blower (i2) and blower (j2). The fabric is fed by conveyor belt (k) from under the drum (e2) to the outlet of the dryer (g). In dryer (g), the fabric travels a distance of about 2 m and warm air blows in the direction from the fabric exit to the entry point. The last take-off roller (h) is manually operated to control the speed of rotation so as to maintain approximately constant sagging of the fabric between the conveyor belt and the last roller.

In FIG. 20 shows the construction of the drum (e1), including its internal structure.

The inner part of the drum (e1) by a partition (o1) is divided into a rarefaction region (q1) and a normal pressure region. A gas blower (m1) is installed at the place where the drum contacts the fabric, and the gas exiting from it blows particles out of the holes passing by the gas blower (m1). In the drum (e1) there is another gas blower (n1), gas from which blows out particles that were not blown onto the fabric, these particles fall into the container of remaining particles (p1).

In FIG. 21 shows the construction of the drum (e2), including its internal structure.

The inner part of the drum (e2) by a partition (o2) is divided into a rarefaction region (q2) and a normal pressure region. A gas blower (m2) is installed at the place where the drum contacts the fabric, and the gas exiting from it blows particles from the holes passing by the blower (m2). In the drum (e2) there is another gas blower (n2), the gas from which blows out the remaining particles onto the fabric, which were not immediately blown onto the fabric.

In this example, particles of water-absorbing resin from 850 to 1200 μm in size were used, obtained as described in Production 1. 1 kg of such resin particles were placed in each of the feed hoppers (d1) and (d2). Each time, when the amount of resin during operation of the device was reduced to approximately 300 g, up to 1 kg of resin was added to the funnels. This is necessary in order to avoid complete emptying of the funnels during operation. The pressure in the rarefaction areas (q1) and (q2) was reduced through the axis of the drum to approximately 700-750 mm and then maintained at that level. Air was introduced into the blowers (i1) and (i2) and the volume of blown air was adjusted so that most of the particles adhering to parts of the drum other than the holes moved air back into the funnels. Dry blower air was supplied through blowers (j1) and (j2) to dry the surface of the drum. Gas was supplied through the blowers (m1), (m2), (n1) and (n2). Gaseous nitrogen with a temperature of 180 ° C was passed through the dryer (g) in the direction from the place of exit of the fabric to the place of entry with a flow rate of 50 m ³ / h. The amount of water sprayed through the water spray was adjusted so that the water content in the Bemliese material was 200 g of water / m ² at a material speed of 0.2 m / min.

Due to the rotation of the drums (e1) and (e2) and the conveyor belt (k), uniform movement of the fabric was ensured, and after setting the speed of the fabric to approximately 0.3 m / min, the process was started.

During operation, the pickup roller (h) was manually actuated to maintain approximately constant sagging of the fabric between the conveyor belt (k) and the pickup roller (h).

The fabric coming down from this roller in the period from 20 to 60 minutes from the beginning of the technological process was subjected to various studies.

Evaluation of Absorbent Composite Material Produced: Bond Resin and Fabric

A square with a side of 10 cm was cut from the absorbent composite material obtained in Example 40, and the type of bond between the fibers of the nonwoven material and the absorbent resin was examined using an optical microscope. The fibers were passing through the resin.

Evaluation of the absorbent composite produced: weight ratio of resin in the absorbent composite

A portion of the absorbent composite material produced in Example 40 was divided into pieces 50 cm long and 10 pieces were selected to measure the proportion of resin. The weight ratio of the resin ranged from 82 to 86% by weight. That is, there was a slight fluctuation of this value in the resulting absorbent composite material. This absorbent composite material was divided into pieces 50 cm long and 10 pieces were randomly selected to measure the proportion of resin. The proportion of resin varied significantly from 70% by weight. up to 90% by weight, indicating that this fabric is characterized by an unstable weight ratio of resin. The weight ratio of the resin in the absorbent composite was calculated in the same manner as in Example 42, described below.

Evaluation of Absorbent Composite Material Produced: Bond of Absorbent Resin and Fabric

A 50 cm long piece was cut from the absorbent composite material obtained in Example 40 and hung on a bar fixed at a height of about 1 m; for 60 s, the plank was shaken up and down at a speed of 15 cm / s and an amplitude of 30 cm. The weight ratio of resin in this absorbent composite material was 84% by weight, and only 5 resin particles separated.

Evaluation of the absorbent composite material produced: amount of absorbed fluid in the absence of load

The amount of liquid absorbed by the absorbent composite material obtained in Example 40 in the absence of load was 61 g / g. Absorption capacity per unit area was 1 g / cm ² .

Example 41

The process was carried out as in Example 40, except for the use of particles of water-absorbing resin obtained as described in Production section 3.

Evaluation of the absorbent composite material produced: area occupancy of the absorbent composite material by resin

The occupancy of the area on one side of the absorbent composite material obtained in Example 41 was 15.5%.

Evaluation of the absorbent composite material produced: the relationship of the water-absorbing resin and fabric

A piece of 50 cm long was cut from the absorbent composite material obtained in Example 41 and hung on a bar fixed at a height of about 1 m; for 60 s, the plank was shaken up and down at a speed of 15 cm / s and an amplitude of 30 cm. The weight ratio of resin in this absorbent composite material was 85% by weight, and only 20 resin particles separated.

Example 42 (the water content in the base material is less than 0.5% by weight.)

The process was carried out as in Example 40, except that the amount of water sprayed with the sprayer was less so that the water content in the Bemliese material after passing the sprayer was 0.3% by weight.

For evaluation used tissue removed from the device 20-60 minutes after the start of the process. A 50 cm long piece was cut from the absorbent composite material and hung on a strap fixed at a height of about 1 m; for 60 s, the bar was shaken up and down at a speed of 30 cm / s and an amplitude of 30 cm. The weight ratio of resin in this absorbent composite was 30% by weight. or less. A low water content was associated with a small amount of resin particles. The amount of resin in a given absorbent composite was determined by subtracting the weight of the fabric from the total weight of the absorbent composite. The weight of the fabric included in the absorbent composite material was obtained by multiplying 0.25 m ² by the dry tissue density before use (g / m ² ), measured in advance, with the assumption that the area of the piece was 50 cm long, cut for carrying out the described measurement is 0.25 m ² . The weight ratio of the resin in the absorbent composite was obtained as a percentage by dividing the weight of the resin included in the absorbent composite, calculated as described above, by the total weight of the absorbent composite.

Example 43 (the water content in the particles of the water-absorbing resin is more than 50% by weight.)

1 kg of particles of water-absorbing resin was placed in a 10 L teflon container and 2 kg of water was added simultaneously with vigorous stirring. When almost all the water was absorbed into the particles of the water-absorbing resin, the mixing was completed. The technological process was carried out in the same manner as in Example 40, except for the use of particles of water-absorbing resin prepared by the described method. For evaluation used tissue removed from the device 20-60 minutes after the start of the process. The resulting absorbent composite material was divided into pieces 50 cm long and 10 pieces were randomly selected to measure the weight ratio of the resin. Its value fluctuated greatly in the range from 70% weight. up to 90% by weight, which indicates an unstable weight ratio of the resin. The weight ratio of the resin in the absorbent composite was calculated in the same manner as in Example 42.

Example 44 (The outer diameter of the holes on the surface of the drum was more than 3 times the average particle size of the water-absorbing resin)

The technological process was carried out as in Example 40, except that the diameter of the holes on the surface of the drums (e1) and (e2) was 4 mm. For evaluation used tissue removed from the device 20-60 minutes after the start of the process. The resulting absorbent composite material was divided into pieces 50 cm long and 10 pieces were randomly selected to measure the weight ratio of the resin. Its value fluctuated greatly in the range from 92% weight. up to 75% wt., which indicates an unstable weight ratio of the resin. The weight ratio of the resin in the absorbent composite was calculated in the same manner as in Example 42.

Example 45 (The depth of the holes on the surface of the drum was more than 2 times the average particle size of the water-absorbing resin)

The technological process was carried out in the same way as in Example 40, except that the depth of the holes on the surface of the drums (e1) and (e2) was 4 mm, not 0.8 mm. For evaluation used tissue removed from the device 20-60 minutes after the start of the process. The resulting absorbent composite material was divided into pieces 50 cm long and 10 pieces were randomly selected to measure the weight ratio of the resin. Its value fluctuated greatly in the range from 92% weight. up to 75% wt., which indicates an unstable weight ratio of the resin. The weight ratio of the resin in the absorbent composite was calculated in the same manner as in Example 42.

Example 46 (Using PET-Based Nonwoven Fabric)

The resin applying device worked in the same mode as in Example 40, except for using PET-based non-woven fabric. For evaluation used tissue removed from the device 20-60 minutes after the start of the process. A piece of a length of 50 cm was cut from the obtained absorbent composite material and hung on a bar fixed at a height of about 1 m; for 60 s, the bar was shaken up and down at a speed of 15 cm / s and an amplitude of 30 cm. The weight ratio of resin in this absorbent composite material was 30% by weight. or less, a small amount of particles was associated with PET-based nonwoven fabric. The weight ratio of the resin in the absorbent composite was calculated in the same manner as in Example 42.

Example 47 (Using PP nonwoven fabric)

The resin applying device worked in the same mode as in Example 40, except for using non-woven material based on PP as a fabric. For evaluation used tissue removed from the device 20-60 minutes after the start of the process. A piece of a length of 50 cm was cut from the obtained absorbent composite material and hung on a bar fixed at a height of about 1 m; for 60 s, the bar was shaken up and down at a speed of 30 cm / s and an amplitude of 30 cm. The weight ratio of resin in this absorbent composite was 30% by weight. or less, a small amount of particles was associated with PP-based nonwoven fabric. The weight ratio of the resin in the absorbent composite was calculated in the same manner as in Example 42.

Example 48

A piece of 37 cm long and 21 cm wide was cut from Bemliese® material. A piece of 37 cm long and 21 cm wide was cut from Teflon® material and a line was drawn on it with a length of 35 cm and a width of 19 cm. Another such piece was prepared. As large particles, 6.6 g of particles from 1000 to 1180 μm in size were used, obtained as described in Production 1, which were evenly distributed inside the drawn line using a sieve with a mesh size of 1180 μm. Similarly, 6.65 g of particles ranging in size from 212 to 300 μm, obtained as described in Production 1, were used as small particles and evenly distributed using a sieve with a mesh size of 300 μm. 6.7 g of Particles ranging in size from 1000 to 1180 μm were distributed in the same manner on another sheet. Using a sprayer, 8 g of water was applied to the Bemliese® material, then the material was laid on resin particles and pressed. An additional 2 g of water was applied to the Bemliese® material and bonded to the resin particles from the back. An additional 3 g of water was applied to the Bemliese® material, and then it was dried for 10 minutes at 180 ° C in an inert atmosphere furnace, while the part of the material on which there was no resin was pressed with a load to prevent the Bemliese® material from shrinking .

Prepared Munee Nobiru Fit® diaper manufactured by Unicharm Co., Ltd. size M, the upper and lower sheets were separated from it by melting hot melt adhesive using the heat of a dryer. A piece of 33 cm long and 17 cm wide was cut from the absorbent composite material produced and laid between these sheets to form a layered structure, while the edges of the upper and lower sheets not in contact with the absorbent composite material were glued to each other using a non-corrosive quick-drying adhesive sealant TSE397 manufactured by GE Toshiba Silicones Co., Ltd. having thus obtained an article for the absorption of body fluids, which has become an example 48.

Example 49

Munee Nobiru Fit® Diaper Absorber manufactured by Unicharm Co., Ltd. size M was disconnected and the pulp was placed together with the water-absorbing resin in a vibrating screen. The pulp was harvested with tweezers because it was aggregated. This work was continued until the water-absorbing resin was completely separated from the pulp. An absorbent composite material was prepared in the same way as in Example 48, distributing on it with a sieve 3 g of the specified pulp. Then, in the same manner as in Example 48, a layered structure was formed using the upper and lower sheets to form an article for absorbing body fluids. The sensations caused by contact with this product have been improved by adding a layer of pulp.

Example 50

A product for absorbing body fluids was prepared in the same way as in Example 48, with the exception of changing the size of large particles from a range from 500 to 600 μm to a range from 1000 to 1180 μm, small particles were not used. This product is presented as Example 50.

Example 51

A product for absorbing body fluids was prepared in the same way as in Example 48, except for changing the size of large particles to a range from 710 to 850 microns, using large particles in an amount of 4.65 g on each side, changing the size of small particles to a range from 300 to 425 microns and the use of fine particles in an amount of 10 g. This product is presented as Example 51.

Example 52

An article for absorbing body fluids was prepared in the same manner as in Example 48, except for using resin particles obtained as described in Production section 3. This article is presented as Example 52.

Example 53

The body fluid absorbent article was prepared in the same manner as in Example 48, except that the absorbent composite material and the waterproof sheet were glued together using water-repellent hot-melt adhesive ME117 manufactured by Japan NSC Co., Ltd., as shown in FIG. 22. This product was Example 53. The adhesive was sprayed onto the absorbent composite material vertically and horizontally, as can be seen from FIG. 22. This absorbent composite was stable and did not move within the product.

Example 54

A product for absorbing body fluids was prepared in the same way as in Example 48, except for the use of large particles of resin ranging in size from 710 to 850 microns on both sides, 6.1 g on each side, and 4 g of resin particles ranging in size from 212 to 300 microns - as fine. This product is presented as Example 54.

Reference Example 13

As Comparative Example 13, a Munee Nobiru Fit® Size M diaper manufactured by Unicharm Co., Ltd. was used. In it, the absorber was a mixture of pulp and water-absorbing resin, was thick and had a low absorption capacity.

Reference Example 14

As Comparative Example 14, a Pampers Cotton Care® Size M diaper manufactured by P&G Co., Ltd. was used. In it, the absorber was a mixture of pulp and water-absorbing resin, was thick and had a low absorption capacity.

The physical properties of products for the absorption of body fluids, which are Examples 48-54 and Comparative examples 13 and 14, are shown in table 7.

Example 55

In Example 55, an article for absorbing body fluids was prepared in the same manner as in Example 48, except for the following changes.

Chunks of 37 cm long and 25 cm wide were cut from Bemliese® and Teflon. A line 35 cm long and 23 cm wide was drawn on the Teflon sheet. 8.0 g and 8.1 g of large particles were distributed on the front and back surfaces and 8 g, respectively fine particles.

A piece of 33 cm long and 21 cm wide was cut from the composite material obtained and placed between the top and bottom sheets folded as shown in FIG. 23.

Example 56

The product for absorbing body fluids was prepared in the same way as in Example 55, except for the use of large particles ranging in size from 500 to 600 microns and the absence of small particles. This product constituted Example 56.

Example 57

A body fluid absorbing product was prepared in the same manner as in Example 55, except for using the water-repellent glue ME117 manufactured by Japan NSC Co., Ltd. This product constituted Example 57.

The physical properties of products for the absorption of body fluids, which are Examples 55-57, are shown in table 8.

Example 58

In Example 58, an article for absorbing body fluids was prepared in the same manner as in Example 48, except that the absorbent composite was glued to a water-permeable sheet and a waterproof sheet using the adhesive drawing pattern shown in FIG. 24.

Example 59

In Example 59, an article for absorbing body fluids was prepared in the same manner as in Example 58, except for using the water-repellent glue ME117 manufactured by Japan NSC Co., Ltd.

Example 60

In Example 60, an article for absorbing body fluids was prepared in the same manner as in Example 50, except that the absorbent composite was glued to a water-permeable sheet and a waterproof sheet using the adhesive drawing pattern shown in FIG. 24.

The physical properties of products for the absorption of body fluids, which are Examples 58-60, are shown in table 9.

Description of drawings

Figure 1 is an explanatory diagram of an acceptable device for the production of absorbent composite material, which is the object of the present invention.

FIG. 2 is an explanatory diagram of an apparatus for measuring the absorption capacity of an absorbent composite material that is an object of the present invention.

In FIG. 3 is an enlarged view showing a diagram of the measuring element 5 of FIG. 2.

In FIG. 4 shows examples of the shape of the absorbent composite material, characterized by a larger value in length.

In FIG. 5 shows an example of folding an absorbent composite material.

In FIG. Figure 6 shows an example of folding an absorbent composite.

In FIG. 7 shows an example of folding an absorbent composite material.

In FIG. 8 illustrates an example of folding an absorbent composite.

In FIG. 9 shows an example of folding an absorbent composite material.

In FIG. 10 illustrates an example of folding an absorbent composite.

In FIG. 11 shows an example of folding an absorbent composite material.

In FIG. 12 shows an example of folding an absorbent composite.

In FIG. 13 shows examples of glue application patterns.

FIG. 14 is an explanatory diagram for conducting a leak assessment test.

FIG. 15 is an explanatory diagram for conducting a leak assessment test.

In FIG. 16 is an electron microscope image showing the penetration of fibers into an absorbent resin upon binding.

FIG. 17 is an explanatory diagram of one of the devices for manufacturing an absorbent composite material that is an object of the present invention.

FIG. 18 is a simplified diagram of the location of the holes on the surface of a drum included in a device, the circuit of which is shown in FIG. 17.

FIG. 19 is a simplified cross-sectional diagram of the holes on the surface of a drum included in a device whose circuit is shown in FIG. 17.

FIG. 20 is a simplified diagram of a first drum included in a device, a circuit of which is shown in FIG. 17.

FIG. 21 is a simplified diagram of a second drum included in a device, a diagram of which is shown in FIG. 17.

In FIG. 22 shows a glue application pattern in an Example of an article for absorbing body fluids 53.

FIG. 23 is a simplified diagram of the structure of an article for absorbing body fluids in Example 55.

FIG. 24 is a simplified diagram of the structure of an article for absorbing body fluids in Example 58.

Claims (28)

1. Absorbing composite material for absorbing body fluids containing a base material and particles of water-absorbing resin with a particle size of from 100 to 2700 μm, where
the base material is fabric and / or paper, and
the water-absorbing resin constituting the particles of the water-absorbing resin is a copolymer formed mainly by salts of polyacrylic acid,
for which the following conditions are met (1) - (4):
(1) the weight ratio of the amount of water-absorbing resin to the total amount of base material and water-absorbing resin is from 65 to 99 wt.%,
(2) the number of particles of water-absorbing resin directly related to the base material is 50 wt.% Or more of the total number of particles of water-absorbing resin,
(3) the average absorption capacity of the particles of water-absorbing resin is 50 g / g or more,
(4) the amount of unreacted monomers in the water-absorbing resin is 200 ppm or less. 2. The absorbent composite material according to claim 1, in which the area occupancy by resin particles ranging in size from 550 to 2100 microns, at least on one side of the base material is from 1 to 30%. 3. The absorbent composite material according to claim 1 or 2, in which the coefficient of the total surface area is from 0.3 to 3. 4. The absorbent composite material according to claim 1, wherein the salt concentration at the surface of the particles of water-absorbing resin ranging in size from 550 to 2100 μm after binding to the base material is at least 10 mol% lower than the salt concentration in the center of the particles. 5. The absorbent composite material according to claim 1, in which the resin is crosslinked on the surface of the particles of water-absorbing resin ranging in size from 550 to 2100 μm. 6. The absorbent composite material according to claim 1, in which the particle size distribution of the particles according to the size of the water-absorbing resin meets the following conditions (1) and (2):
(1) particles that can pass through a sieve with a mesh size of 300 μm comprise from 10 to 50 wt.% Of the total weight of the water-absorbing resin;
(2) particles that cannot pass through a sieve with a mesh size of 3000 μm comprise 10 wt.% Or less of the total weight of the water-absorbing resin. 7. The absorbent composite material according to claim 1, in which the particles of the water-absorbing resin are amorphous particles of the water-absorbing resin obtained by polymerization of an aqueous solution followed by grinding, and / or resin particles obtained by suspension polymerisation with phase reversal. 8. The absorbent composite material according to claim 1, in which the surface strength of the particles of the water-absorbing resin before binding to the base material is from 0.1 to 5.5 N. 9. The absorbent composite material according to claim 1, in which the absorption capacity under pressure of the particles of the water-absorbing resin is 20 g / g or more. 10. The absorbent composite material according to claim 1, in which the water-absorbing resin constituting the particles of the water-absorbing resin is a resin with acid groups in the side chains, and 50% or more of the acid groups of the water-absorbing resin are neutralized to form ammonium salts before binding to the base material . 11. The absorbent composite material according to claim 1, in which the contact angle of the base material with an aqueous solution of ammonium polyacrylate with a viscosity of 74 cP is 130 ° or less. 12. The absorbent composite material according to claim 1, in which the tensile strength of the base material after absorption of the salt solution is 0.6 N / 20 mm or more both in the longitudinal and transverse directions. 13. The absorbent composite material according to claim 1, in which the following conditions (1) and (2) are satisfied for the base material:
(1) the ratio of tensile elongation in tension in the longitudinal and transverse directions is from 1: 1.2 to 1:10;
(2) the ratio of tensile strengths in the longitudinal and transverse directions is from 1.2: 1 to 10: 1. 14. The absorbent composite material according to claim 1, wherein the absorption capacity of the base material is 6 g / g or more. 15. The absorbent composite material according to claim 1, in which the absorption rate of the base material is 0.35 mg / s or more. 16. The absorbent composite material according to claim 1, in which the base material is paper and / or fabric consisting of cellulose fibers. 17. The absorbent composite material according to clause 16, in which the base material is a cellulosic non-woven fabric. 18. The absorbent composite material according to claim 1, in which the edges are bent and fixed. 19. The absorbent composite material according to claim 1, in which the adhesive is applied linearly in the longitudinal direction. 20. The absorbent composite material according to claim 19, in which the adhesive is a hot melt adhesive. 21. A method of obtaining an absorbing composite material for absorbing body fluids containing a base material and particles of a water-absorbing resin with a particle size of 100 to 2700 μm, which consists in saturating the base material and / or water-absorbing resin with water, followed by removing water and drying the base material and water-absorbing resin in which they are in contact with each other, where the base material is fabric and / or paper, and the water-absorbing resin constituting the particles of the water-absorbing resin is polymer formed mainly salts of polyacrylic acid. 22. The method of producing absorbent composite material according to item 21, comprising the following stages (1) to (3):
(1) saturating the particles of the water-absorbing resin and / or the base material with water in an amount of from 10 to 3000 wt.% Of the particles of the water-absorbing resin, which must be bound;
(2) bringing the base material into contact with particles of a water-absorbing resin;
(3) removing water and drying the base material and particles of the water-absorbing resin. 23. The method of producing an absorbent composite material according to item 21 or 22, in which the drying conditions correspond to a heating temperature of from 70 to 350 ° C and a processing time of from 1 to 1000 s. 24. The method of producing an absorbent composite material according to item 23, in which the particles of water-absorbing resin used are particles in which the concentration of salt on the surface was reduced by drying by heating by 10% or more compared with the value before the heat treatment. 25. A device for producing an absorbing composite material for absorbing body fluids containing a base material and particles of water-absorbing resin with a particle size of from 100 to 2700 μm, including a node for supplying the base material; a rotary drum for binding resin particles to a base material; a unit for supplying resin particles to the rotary drum; a drying unit for removing water from the base material and associated resin particles; a unit for supplying a certain amount of moisture to the base material and / or resin particles; Where
the base material is fabric and / or paper, and
the water-absorbing resin constituting the particles of the water-absorbing resin is a copolymer formed mainly by polyacrylic acid salts, where the device has the following characteristic features (1) and (2):
(1) the surface of the rotating drum has many holes,
(2) there is a vent in the bottom of each hole through which gas can escape from the inside of the rotating drum. 26. A method of producing an absorbent composite material for absorbing body fluids according to claim 25, which comprises bonding particles of a water-absorbing resin with a particle size of 100 to 2700 μm with a base material, followed by drying the particles of a water-absorbing resin and a base material, where
the base material is fabric and / or paper, and
the water-absorbing resin constituting the particles of the water-absorbing resin is a copolymer formed mainly by salts of polyacrylic acid,
where the method satisfies the following conditions (1) - (5):
(1) the water content in the base material before applying the particles is from 50 to 500 wt.%;
(2) the water content in the particles of the water-absorbing resin before application to the base material is from 1 to 50 wt.%;
(3) particles of the water-absorbing resin adhere to the base material as a result of applying these particles, previously placed in the holes of the rotating drum, to the base material by contacting the tissue-like base material with the surface of the rotating drum;
(4) the outer diameter of the hole of the holes on the surface of the rotating drum is from 1 to 3 maximum diameters of the particles of water-absorbing resin used;
(5) the depth of the holes on the rotating drum is from 0.3 to 2 values of the average particle size of the water-absorbing resin used. 27. Product for absorbing body fluids, consisting of a liquid-permeable sheet, a liquid-impermeable sheet and an absorbent composite material according to any one of claims 1 to 22, located between these sheets. 28. The product for absorbing body fluids according to item 27, further comprising a pulp located between a liquid permeable sheet and a liquid impermeable sheet.

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