Modified polysaccharides with improved absorption properties and methods for their production

 

(57) Abstract:

Describes how to get swelling in water insoluble in water carboxylicacid, including the stage of the preparation of a homogeneous mixture consisting of water-soluble polysaccharide and water allocation specified polysaccharide from the above-mentioned mixture and heat treatment specified selected carboxylterminated at 200 - 250oC for 50 - 90, as well as the polysaccharide obtained in this way. Swelling in water insoluble polysaccharide has an initial value of the absorption capacity under load of at least 17 g/g and retains at least about 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least 30%. 6 C. and 39 C.p. f-crystals, 26 tab., 1 Il.

The present invention relates to modified polysaccharides having improved absorption properties. More specifically, the present invention relates to a modified polysaccharides having improved ability to absorb fluid at an ambient pressure and after aging, and the method of obtaining these polysaccharides.

Know the use of NABA personal hygiene, containing absorbents. Such absorbent materials /absorbents/ usually are used in absorbing moisture products, such as diapers, training pants, products for adults suffering from incontinence, and articles for feminine hygiene, in order to increase the absorbent capacity of such products while reducing their total volume. Such absorbents are typically in absorbing moisture products in the fibrous matrix of drevesnosmolyanoy wool. Matrix of drevesnosmolyanoy wool usually has an absorption capacity of about 6 grams of fluid per gram of cotton. Absorbents described above, typically have an absorption capacity than their weight in water at least 10 times, preferably 20 times, and often up to 100 times.

It is obvious that the use of such absorbent products for personal hygiene can reduce the overall volume and at the same time to increase the absorptive capacity of these products.

Described a large number of different materials that can be used as absorbents such products for personal hygiene. These materials include natural substances such as agar, pectin, natural resins, carboxyethylgermanium starch and carboxymethylchitin. Although it is known that the absorbents based on natural materials are used in products for personal hygiene, their use in such products are not widely spread. The use of absorbents from natural materials in products for personal hygiene was not widespread at least in part because their absorption properties are usually worse in comparison with synthetic absorbents, such as polyacrylates. In particular, many natural materials swelling in liquids tend to form a soft gelatinous mass. In the case of use in the absorbent articles of the presence of such a soft gelatinous mass prevents the transport of fluid in the fibrous matrix, which contains these absorbents. This phenomenon is known as the gel - blocking. Once gel-blocking, subsequent portions falling on the product fluid can not effectively absorbed by the product, and the product begins to flow the liquid. In addition, many natural materials have poor absorption properties, especially when exposed to external pressure.

In contrast, synthetic absorbents are often capable of absorbing large to the in absorbent articles and the probability gel blocking is minimal.

Materials on the basis of karboksimetsiltsellyulozy and other modified polysaccharides known in the art. As a rule, carboximethilcellulose materials derived from cellulose material, which process carboxyethylidene reagents such as chloralkali acid, preferably monochloracetic acid and alkali, such as sodium hydroxide, possibly in the presence of alcohol. Such a process is described, for example, in U.S. patent 3723413, issued March 27, 1973 Chatterjee and other Such karboksimetsiltsellyulozy usually soluble in water. Known methods of transformation of such water-soluble carboxymethylcellulose in water-insoluble products.

In U.S. patent 2639239, issued may 19, 1953 Elliot described the way in which commercially available water-soluble salt of alkaline metal carboxymethyl cellulose with a degree of substitution of from 0.5 to 1 is subjected to heat treatment for 10 hours, as a result of which such water-soluble carboxymethylcellulose acquires the ability to form gel particles with a high degree of swelling.

Similarly, in U.S. patent 3723413 discussed above, the comrade and by-products, as a result of which karboksimetilcelljuloza becomes insoluble in water and acquires the desired absorption and retention properties and characteristics.

In U.S. patent 3345358, issued October 3, 1967 Inklaar described a method of obtaining a gel-forming derivatives of polysaccharides, such as karboksimetilirovaniya starch. The method consists in the acidification of finely carboxymethylated esters of polysaccharides by treating them with acid in methanol or other miscible with water and organic liquids. In this way in the original substance are injected acid carboxymethyl group. The substance is kept in a sour, Nagykanizsa environment, which leads to the formation of ester groups, which is the binding of macromolecules processed substances with each other. Then the substance is neutralized with alkali. As described in the patent, thus obtained derivative capable of forming a gel by adding water.

In U.S. patent 3379720, issued April 23, 1968 Reid, described the process for production of modified polysaccharides, such as ethers and esters of cellulose, which includes the suspension of water-soluble polysaccharide in any inert environment, podkislenija.

In U.S. patent 4689408, issued August 25, 1987 Gelman and others, describes a method for salts of carboxymethylcellulose. The method includes processing carboxymethylcellulose water, adding herstories for carboxymethyl cellulose and the allocation of carboxymethyl cellulose. Specifies that the carboxymethyl cellulose has an absorptive capacity of at least 25 grams of fluid per gram of carboxymethyl cellulose.

Unfortunately, the known modified polysaccharides do not have the absorptive properties, comparable with many synthetic materials with high absorption capacity. This prevented the widespread use of such carboxylterminated as absorbents in products for personal hygiene.

It is desirable to develop and to obtain a material with high absorption capacity based on natural substances, which are stable in time absorption properties similar to the properties of synthetic materials with a high absorption capacity, and therefore suitable for use in absorbent articles for personal hygiene.

The present invention relates to swelling in water insoluble in water carboxylterminated. Ka is oblasti under load /AUL/ and has an effective resistance of the absorption properties after aging.

One of the embodiments of the present invention relates to carboxylicacid, which has an initial value of the absorption capacity under load of at least about 14 and retains at least about 50% of this value after aging for 60 days at 24oC and at a relative humidity of at least 30%.

The present invention also relates to methods of obtaining swelling in water, insoluble in water carboxylicacid, which has an effective initial value of the absorption capacity under load and has an effective resistance of the absorption properties after aging.

One method proposed in the present invention, includes the stage of preparation of the mixture consisting of water-soluble carboxylicacid, water and cross-linking agent. Carboxylterminated separated from the mixture and subjected to heat treatment at high temperature for such a period of time that is required to carboxylterminated had an effective initial value of the absorption capacity under a load and the effective stability of the absorption properties after aging.

One of the variants of Ishida, water and a crosslinking agent; the selection of the specified carboxylterminated of the above-mentioned mixture; and heat treating the specified selected carboxylterminated at a temperature above the 50oC during the time required for stitching the specified carboxylterminated to make the specified carboxylterminated swelling in water and insoluble in water, so that swelling in water insoluble in water carboxylterminated had initial value of the absorption capacity under load of at least about 14 and retains at least about 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and at a relative humidity of at least 30%.

Another method proposed in the present invention, includes the stage of preparation of the mixture consisting of water-soluble carboxylterminated and water. Carboxylterminated separated from the mixture and subjected to heat treatment at a certain temperature for a certain period of time, so that carboxylterminated after treatment was effective initial value of the absorption capacity under load and had effective stabilin MESI, consisting of water-soluble carboxylterminated and water; the selection of the specified carboxylterminated of the above-mentioned mixture; and heat treatment of the specified selected carboxylterminated at a temperature of from 200 to 250oC during the time interval from 50 to 90 seconds, and during a specified heat treatment is stitching specified carboxylicacid, with the result that he acquires the ability to swell in water and not dissolve in water, and swelling in water and insoluble in water carboxylterminated has an initial value of the absorption capacity under load of at least 14 and retains at least 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least 30%.

Another method proposed in the present invention, includes the stage of preparation of the mixture consisting of water-soluble carboxylterminated and water, and this mixture has a pH of from 4.0 to 7.5. Carboxylterminated separated from the mixture and subjected to heat treatment at a certain temperature for a certain period of time, so that carboxyethylpyrrole absorption properties after aging.

One of the options for implementing such a method comprises preparing a mixture consisting of water-soluble carboxylterminated and water, where the pH of the mixture is from 4.0 to 7.5, the allocation of the specified carboxylterminated of the above-mentioned mixture; and heat treatment of specified isolated from a mixture of carboxylterminated at a temperature above the 50oC for a time effective to bind the specified carboxylicacid, resulting in the specified carboxylterminated acquires the ability to swell in water and becomes water-insoluble and swellable in water and insoluble in water carboxylterminated has an initial value of the absorption capacity under load of at least 14 and retains at least 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least 30%.

Another method proposed in the present invention, includes the stage of preparation of the mixture consisting of water-soluble carboxylicacid, citric acid, catalyst and water. Carboxylterminated separated from the mixture so that carboxyethylpyrrole absorption properties after aging.

One of the options for implementing such a method includes obtaining a mixture consisting of water-soluble carboxylicacid, water, citric acid and hypophosphite sodium, and the allocation of the specified carboxylterminated of the above-mentioned mixture, and the obtained swelling in water, insoluble in water carboxylterminated has an initial value of the absorption capacity under load of at least 14 and retains at least 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least 30%.

Another method proposed in the present invention, includes the stage of preparation of the mixture consisting of water-soluble carboxylicacid, aluminum ion and water. Carboxylterminated separated from the mixture so that it had an effective initial value of the absorption capacity under a load and the effective stability of the absorption properties after aging.

One of the options for implementing such a method comprises preparing a mixture consisting of water-soluble carboxylicacid, water and cross-linking agent containing aluminum ion, and highlight the action in the water carboxylicacid, which has an initial value of the absorption capacity under a load equal to at least 14, and stores at least 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least 30%.

Another method proposed in the present invention, includes the preparation of carboxylterminated in the form of the reaction dispersion, highlighting carboxylterminated from the reaction dispersion, the mixture consisting of the selected carboxylterminated and water, and the allocation of carboxylterminated from the mixture; carboxylterminated contains an effective amount of the original crystal structure of the polysaccharide so that carboxylterminated has an effective initial value of the absorption capacity under a load and the effective stability of the absorption properties after aging.

One of the options for implementing such a method includes:

A. Preparation of the reaction dispersion containing a solvent and a polysaccharide, which has the original crystal structure;

b. Adding carboxyaniline reagent to the reaction of dispea carboxylicacid;

C. Selection of carboxylterminated from the reaction dispersion;

d. Preparation of a mixture consisting of selected carboxylterminated and water; and

e. The selection of carboxylterminated from the mixture, and the selected carboxylterminated contains so many of the original crystal structure of the polysaccharide, which allows you to get swelling in water, insoluble in water carboxylterminated having initial value of the absorption capacity under a load equal to at least 14, and which retains at least 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and at a relative humidity of at least 30%.

The drawing shows a device for determining values of the absorption capacity under load for absorbent material.

In one aspect, the present invention relates to swelling in water, insoluble in water, the modified polysaccharide, which initially has an effective absorption properties and retains these properties after aging.

Modified polysaccharides suitable for use in the present izopet modified polysaccharide with the desired initial and time-stable absorption characteristics, as described herein. As used in this description, the modified polysaccharide is soluble in water, if it is mainly dissolved in the excess water with the formation of a true solution, losing its original shape dispersed powder molecular and becoming dispersed in aqueous solution. An alternative to this, the modified polysaccharide can swell in water to such an extent that it loses its original structure, even if the true solution is not formed. As a rule, water-soluble, modified polysaccharide should not contain a significant number of links, since the crosslinking leads to modified polysaccharides become insoluble in water.

Used herein, the term "swelling in water, insoluble in water", in relation to a modified polysaccharide means that if you put a modified polysaccharide in an excess of sodium chloride in water with a concentration of 0.9 wt.%, it swells to an equilibrium volume, but does not go into solution. By itself, swelling in water, insoluble in water, the modified polysaccharide is typically retains its original physical structure, but during the absorption of water is to be resistant to the flow and adhesion between adjacent particles. Swelling in water, insoluble in water, the modified polysaccharide used in the present invention, effectively crosslinks that it became practically insoluble but capable of beginning to absorb sodium chloride solution in water with a concentration of 0.9 weight. % in excess of its own weight at least 14 times under applied external load of about 0.3 pound per square inch /0,021 kg/cm2/.

Modified polysaccharides suitable for use in the present invention include, without limitation, karboksilirovanie, sulfonated, sulfated and phosphated derivatives of polysaccharides, their salts and mixtures thereof. Examples of suitable polysaccharides are cellulose, starch, guar, carrageenan, agar, Gellan gum, chitin, chitosan, and mixtures thereof.

Carboxylterminated suitable for use in the present invention include karboksimetsiltsellyulozy, such as carboxymethylcellulose, karboksimetilcelljuloza, carboxyethylgermanium starch, carboxyethylgermanium carrageenan, carboxyethylgermanium agar, carboxyethylidene Gellan resin and mixtures thereof. The preferred carboxylterminated is carbox">

Ways of getting carboxylterminated known to specialists in this field. As the source material used polysaccharide, such as wool from wood pulp, cotton, cotton waste, starch and agar. The polysaccharide may be in the form of fibers or fibers, powdered. Typically, the polysaccharide is dispersed in the solvent such as water or alcohol, and the dispersion is added carboxyaniline reagents. Carboxyaniline reagents typically include harukanaru acid, such as monochloracetic acid, and a base such as sodium hydroxide. Carboxyaniline reagents added to the dispersion under conditions that effectively promote the reaction carboxyaniline reagents with polysaccharide and modification of the polysaccharide as a result of this reaction. Such effective conditions can be different, and they usually depend, for example, temperature, pressure, mixing conditions and the relative amounts of starting substances, solvents and reagents used for the modification of the polysaccharide.

One method proposed in the present invention, includes receiving carboxylterminated of polysaccharide, having originally KRISTALLIChESKAYa such functions crystalline part of the polysaccharide, as the ability to form crosslinks, so that the resulting carboxylterminated has an effective initial value of the absorption capacity under load, and effectively retains its absorption properties after aging.

In this process, the polysaccharide is dispersed in the solvent, and carboxyaniline reagents added to the dispersion. Carboxyaniline reagents added to the dispersion under conditions that allow carboxyaniline reagents to effectively respond to and modify the polysaccharide, while maintaining the effective portion of the original crystallinity of the polysaccharide. Such effective conditions can be different and will depend, for example, temperature, pressure, mixing conditions and the types and relative quantities used of the original substances, solvents and reagents. Usually then carboxylterminated separated from the dispersion. After that, the selected carboxylterminated dispersed in water mixture and extracted from the mixture using, for example, the methods described here. Such allocated from a mixture of crystalline cross-linked carboxylterminated contains such a quantity of the crystalline structure of the original polysaccharide, kotorogo the amount of absorption under load and effective stability after aging.

It is known that many polysaccharides, such as cellulose and chitin, are vysokochastotnymi substances. The degree of crystallinity depends on the source of the polysaccharide and its previous treatment. Highly ordered crystalline structure and less ordered amorphous regions usually have a different reactivity in relation to acting on the polysaccharide reagents. The result of this difference in reactivity is that the amorphous region is usually replaced in the first and in the greatest degree, and vysokochastotnye region are replaced in the last and the least. Swelling of the polysaccharide in the alkali improves access modifier reagents in the crystalline region and facilitates the reaction of the modification. If the total degree of substitution of the polysaccharide is high enough, and the substitution distributed uniformly, then usually achieve complete solubility of the modified polysaccharide in aqueous solution. However, if the total degree of substitution relative low or substitution distributed relatively unevenly received a modified polysaccharide will have a chain structure consisting of alternating soluble is ristalliceski areas remaining after the reaction modification. Thus, the crystalline region functions as a site for the soluble crosslinking of modified segments of the polysaccharide. Such crystallinity of the original polysaccharide or modified the final product can be determined by analytical methods such as optical microscopy or x-ray. Modified product after dispersion in aqueous solution can save some characteristics of the fiber of the original polysaccharide.

Take karboksimetilirovaniya cellulose as an example for discussion. Karboksimetilirovaniya is the process of modification, which, as usually considered, is kinetically controlled and irreversible. Once was substituted for carboxyethylidene groups, the location of these groups in the chain cellulose is usually fixed. Specific distribution scheme carboxymethyl groups in the molecule obtained cellulose depends on the ratio of the reactants and the reaction conditions during synthesis.

In the cellulose more accessible amorphous regions are substituted preferably compared to crystalline regions. Therefore, carboxymethyl golee high degree of substitution allows the substitution in the crystalline regions, that leads to more uniform substitution and a more complete solubility in water.

On the other hand, the preservation of the crystalline areas of natural cellulose can be useful under certain conditions. For example, it was found that crystalline crosslinked carboxymethylcellulose can be obtained in various ways, including the following: use the process as alkali potassium hydroxide instead of sodium hydroxide; using less than the stoichiometric ratio of alkali to carboxyethylidene reagent, such as Chloroacetic acid; the use of lower reaction relations carboxymethyllysine reagent to the pulp; the changing composition of the solvent in the suspension process, or a combination of these different ways of conducting the process. Such reaction conditions can be created in order to facilitate the formation of structures of carboxymethyl cellulose, which are segments of crystalline cellulose, and carboxyethylidene segments in the final molecular structures. One typical result, characteristic of this molecular structure is that when the above-mentioned carboxymethyl cellulose is dissolved in water, the dispersion osteolysis gives a clean and clear solution.

The alkali is used upon receipt of carboxymethyl cellulose as an agent that causes swelling of the cellulose, and a neutralizing reagent to all acids, such as hydrochloric acid released in the reaction of karboksimetilirovaniya. Sodium hydroxide is commonly used as the alkali in the process of industrial production of carboxymethyl cellulose. It was found that the use of potassium hydroxide as the alkali in carboxymethylamino cellulose leads to a more uneven distribution of carboxymethyl groups along the chain of cellulose than using sodium hydroxide, even at relatively vesovoy degree of substitution. This uneven distribution carboxymethyl groups usually helps preserve part of the original crystallites of cellulose in the end carboxymethyllysine that usually leads to improved absorption properties carboxymethyllysine. Conversely, the same process, but using as the alkali sodium hydroxide instead of potassium hydroxide, yields a water-soluble carboxymethyl cellulose with a relatively poor absorption properties.

It can be assumed that the differences between the ISOE is being a larger cation, than the sodium ion may not be able to penetrate some of the crystalline region of cellulose, and as a result, such a crystalline region of cellulose usually remain intact during karboksimetilirovaniya, and forms a reaction product with a more uneven distribution of replacement groups. This uneven distribution of substituting groups can take place even in the carboxymethyl cellulose with a relatively high degree of substitution, for example with a degree of substitution of more than 1.

The use of excessive amounts of alkali with respect to carboxymethyloxime reagent, such as Chloroacetic acid, usually produces a more uniformly substituted carboxymethylcellulose, which is soluble in water, if the degree of substitution is high enough. However, it was found that the lack of alkali with respect to carboxyethylidene the reagent can be obtained is insoluble in water and relatively non-uniformly substituted carboxymethylcellulose with the desired absorption properties. It can be assumed that this phenomenon occurs because the lack of alkali with respect to carboxyethylidene reagent reduces the degree of swelling in the structure of cellulose, which in turn contributes mainly is of relatively low ratio carboxyaniline reagent to the polysaccharide, such as Chloroacetic acid to the cellulose, can also be used to obtain carboxylterminated with the desired absorption properties. In addition, the use of relatively low ratio carboxyaniline agent to polysaccharide usually means lower costs for raw materials and reduction reactions with the formation of by-products, both of these factors are usually beneficial in terms of both economic and environmental reasons.

Such crystalline cross-linked carboxylterminated usually must be processed through a process of homogenization, such as dispersion, and select from the aqueous mixture, but usually there is no need for any additional stages of processing, such as thermal or chemical treatment, in order to obtain the desired initial value of the absorption capacity under load and time-stable absorption properties, as described in this invention.

In the dispersion of the crystalline cross-linked karboksimetsiltsellyulozy in water of the fibrous structure and oriented packing of the molecular chains of the modified cellulose decreases. As soon as soluble segments circuits Carbo is perepletena molecular configuration, which is then stored on drying. In the process of dissolution can also be formed larger aggregates of crystalline regions, which serve as zones of super-link for chains of karboksimetsiltsellyulozy, which enables the formation of a true three-dimensional grid.

Repeated absorption and removal of the fluid, apparently, does not affect the absorption properties of crystalline cross-linked karboksimetsiltsellyulozy. It is believed that the stability of the physical crosslinks should depend on the size of the crystalline regions, which serve as sites for crosslinking. In that case, if the size of the crystalline regions above a certain effective value, for example greater microns, these nodes will be stable and will generally be insensitive to the action of water molecules. With this effective amount of the crystalline areas, there is generally a translucent dispersion of crystalline cross-linked carboxymethyl cellulose in an aqueous solution.

Any method of selection carboxylterminated from the reaction dispersion without unacceptable deterioration of the absorption properties of carboxylterminated suitable for use in the present invention. Examples so n a critical point, etc. However, it should be understood that it is possible to spend carboxyethylidene source of the polysaccharide so that the solution carboxylterminated can be obtained directly, without an intermediate stage of the selection. For example, the process of modification can be done in conditions of low humidity. That is, the initial polysaccharide can be moisten, for example, 1 part of water per part of the original polysaccharide. You can then mix carboxyaniline reagents with moistened source polysaccharide in order to spend carboxyethylidene. After that you can add to carboxylterminated additional amount of water to obtain a mixture of carboxylterminated and water. Thus, do not need any stage of selection between education of carboxylterminated and any subsequent stages of processing, such as the preparation of a mixture of carboxylterminated and water, in order to give carboxylterminated stability in time. However, if the original polysaccharide is too much water, the reaction carboxyethylidene may not be enough.

When carboxylterminated is Sabino has an average degree of substitution of from 0.3 to 1.5, more acceptable from 0.4 to 1.2. The degree of substitution indicates the average number carboxialkilnuyu groups such as carboxymethyl groups present in anhydroglucose link cellulosic material. In General, the maximum average number carboxialkilnuyu groups which may be present in anhydroglucose link cellulose, is 3.0. When karboksimetilcelljuloza has an average degree of substitution ranging from 0.3 to 1.5, karboksimetilcelljuloza usually soluble in water prior to its treatment with the purpose of obtaining karboksimetsiltsellyulozy with the desired initial and stable in time absorptive properties described in this invention. However, experts in this field can determine what other characteristics, such as the true distribution of modifying the substituting groups in the polysaccharide may also affect the solubility of carboxylterminated in water.

The industry produces carboximetilzellulozu with molecular weights over a wide range. Karboksimetilcelljuloza having a relatively high molecular weight, often preferred for use in the present invention. However, for use in the present invention is llulose in terms of the viscosity of its 1.0% /by weight/ water solution at 25oC. Carboxymethyl cellulose suitable for use in the present invention typically has a viscosity of 1.0% /by weight/ water solution at 25oC from 10 CP /10 mPas to 80000 CP /80000 mPas/, preferably from 500 CP /500 mPas to 80000 CP /80000 mPas/ and more preferably from 1000 centipoise /1000 mPas/ to 80000 CP /80000 mPas/.

It was found that cross-linked carboxylterminated having improved absorption properties, which are described in the present invention have a relatively low viscosity aqueous solution compared with carboxypolymethylene, which do not show improved absorption properties, as in the present invention. For example, when measuring the viscosity of a 1% /by weight/ water solution containing 0.9 wt.% sodium chloride /saline/, which tried to reach equilibrium at 25oC, for example, by stirring for 18 hours, it was found that carboxylterminated of the present invention have a viscosity of less than 400 centipoise, preferably less than 300 centipoise and most acceptable - less than 200 centipoise. It was found that carboxylterminated of the present invention have a viscosity that is typically 50%, PR is oxyalkylated, which was not obtained or processed in order to achieve enhanced absorption properties, as described in the present invention. For example, if carboxylicacid, which was not obtained or processed in order to achieve enhanced absorption properties, as in the present invention, has a viscosity of about 800 centipoise, carboxylterminated, which was obtained or processed in order to give him superior absorption properties, as in the present invention will have a viscosity of less than 400 centipoise, preferably less than 320 centipoise, and most acceptable - less than 240 centipoise.

It is found that the method proposed in the present invention leads to improved initial AUL value in the modified polysaccharides with molecular weights over a wide range. Although the modified polysaccharides of high molecular weight is generally preferable, it is important that it is possible to achieve improvement in the modified polysaccharides of low molecular weight. Low molecular weight modified polysaccharides are usually cheaper than the high molecular weight modified polysaccharides. In accordance with this, the use of low molecular weight modified polysaccharides economicseconomics modified polysaccharides, than with aqueous solutions containing high concentrations of high molecular weight modified polysaccharides. This is due to the fact that aqueous solutions of high molecular weight modified polysaccharides have a higher viscosity compared to water solutions containing the same concentration of low molecular weight modified polysaccharides. Moreover, for reasons of efficiency, it is often desirable to prepare an aqueous solution with the highest concentration of modified polysaccharides, so that it was still possible to work effectively with this aqueous solution.

Suitable karboksimetsiltsellyulozy produced by many firms. An example produced by the industry karboksimetsiltsellyulozy is carboxymethyl cellulose manufactured by the firm "Aqualon Company under the trade name "cellulose resin "Agualon or Blanose".

Carboxylterminated described in this invention have the ability to absorb a liquid while under external pressure or load, and this property is called here "absorption capacity under load" /AUL/. It was found that synthetic polymeric materials, such as polyacrylates, which usually has the high is in the composition of absorbent products. The method, which determines the magnitude of the absorption capacity under a load is described below in connection with examples. The magnitude of the absorption capacity under a load is defined as described below and shown in this description, expressed as a number, in grams, of an aqueous solution containing 0.9 wt.% sodium chloride, which can absorb one gram of the modified polysaccharide for 60 minutes under a load, for example, 0.3 psi /0,021 kg/cm2/. As a General rule, it is desirable that carboxylterminated had initial value of the absorption capacity under a load at a load of about 0.3 pound per square inch, at least 14, preferably at least 17, more preferably at least 20, it is acceptable for at least 24, more acceptable, at least 27 and up to 50 g/g Used herein, the term "initial value of the absorption capacity under load" denotes a magnitude AUL, which is carboxylterminated when measured within one day after preparation of carboxylterminated if carboxylterminated stored under normal conditions, such as temperature of approximately 24oC and relative humidity from 30% to 60%. It was found that plavix.ultrasound as it is aging. Even in relatively mild conditions, such as normal - when the 24oC and at a relative humidity of not less than 30%, from 30% to 60%, usually occurs deterioration in the absorption properties of carboxylterminated as it is aging. Typically, these storage conditions, as relatively higher temperatures and/or relatively higher relative humidity compared to normal conditions, can lead to faster and/or more rapid deterioration in the absorption properties of carboxylterminated when they are aging.

Carboxylterminated described in the present invention, tend to keep the initial AUL value after aging. Specifically, carboxylterminated of the present invention can save more than 50% and better over 70% of the initial AUL value after aging for 60 days. As a rule, conditions of aging - this is the usual condition for about 24oC and a relative humidity of at least 30%. For example, if carboxylterminated the present invention has an initial AUL value of about 20, this carboxylterminated can have a value of AUL of at least about 10 and better about 14 after aging for 60 days at the dialkylphosphate not retain their initial AUL value after aging under the same conditions.

Preferably carboxylterminated of the present invention retain more than 50% and more preferably more than 70% of the initial AUL value after aging for 60 days at 24oC and a relative humidity of about 100%.

As described above, carboxylterminated is preferably karboksimetilcelljuloza, such as carboxymethylcellulose or karboksimetilcelljuloza. This karboksimetilcelljuloza has an initial value of the absorption capacity under a load equal to at least 14, preferably at least 17, more preferably at least 20, better at least 24 and even better at least 27, and saves more than 50%, preferably more than 70% of the initial AUL value after aging for 60 days at 24oC and a relative humidity of at least 30%, and preferably retains 50%, preferably more than 70% of the initial AUL value after aging for 60 days at 24oC and a relative humidity of about 100%.

You can state a hypothesis, not considering it is only possible that the phenomenon of reduction AUL over time due to the dissociation of nodes matching carboxylterminated. Nodes joining usually can be divided into two grams of them as ester or amide bond, formed, for example, result from the application of a crosslinking agent based on polyamines, or ionic bonds are formed, for example, be used as a crosslinking agent for polyvalent metal ion, or physical crosslinking formed, for example, of the surviving crystalline structure. The second group are the sites of crosslinks, which may consist of a relatively fragile links, such as hydrogen bonds in the molecule carboxylterminated.

To improve stability during aging of carboxylterminated it is desirable to increase the number of relatively strong links that exist in carboxyethylpyrrole, but not to such an extent that there was a full stitching carboxylterminated. Carboxylterminated described in the present invention, suitable for use in containing absorbents garments and products for personal hygiene, such as diapers, training pants, feminine hygiene products for adults suffering from incontinence, and medical products such as bandages for wounds or surgical blankets or robes.

It was found that the modified polysaccharides described the constituent of carboxylterminated, water and possibly cross-linking agent. This aqueous mixture typically contains from 0.01 to 90 wt.%, preferably from 0.1 to 30 wt.% and more preferably from 2 to 25 wt.% carboxylterminated of the total weight of the mixture. The mixture typically contains from to 99.99 to 10 wt.%, preferably from about 99.9 to 70 wt.% and more preferably from 98 to 75 wt.% water.

I believe that the dissolution of carboxylterminated water mixture leads to the entanglement of individual segments of carboxylterminated with each other. As a result of this weave chain polysaccharide in the mixture interpenetrate and complement each other, so that there arises the molecular configuration in the form of statistical, twisted tangles, which can be put effectively forms a node joining, and which allows additional stitching carboxylterminated during further processing, as for example by heat treatment. To occur of the effective interweaving of individual segments of carboxylterminated with each other, create conditions to before additional processing stages formed a stable homogeneous mixture in equilibrium, to ensure the efficient dissolution of carboxylterminated in the water. With Vratsa in the water. For example, intact crystalline region of the crystalline cross-linked polysaccharide usually do not dissolve in water, whereas the non-crystalline region will dissolve.

Carboxylterminated usually dissolved in a solvent that contains at least 30 wt.% water, preferably 50 wt.% water, better than 75 weight. % water and even better 100 wt.% water. When together with water using a different solvent, that other suitable solvent may be methanol, ethanol and acetone. However, the use of such other, non-aqueous solvents may prevent the formation of a homogeneous mixture, and therefore the chain carboxylterminated will not now go into solution and vzaimopronikayut each other.

Crosslinking agents suitable for use in the present invention are typically soluble in water. One of the suitable cross-linking agent is an organic compound containing at least two functional groups or functionalities capable of reacting with carboxyl, amino or hydroxyl groups carboxylterminated. Preferably, such organic crosslinking agent was selected from the group consisting of diamines, poolaw, primary diamines and primary polyamines and mixtures thereof. Among the diols and polyols are generally more preferred by those that have a large carbon chain length /4/. In particular, a crosslinking agent can be selected from the group consisting of chitosan glutamate, gelatin type a, Diethylenetriamine, ethylene glycol, butyleneglycol, polyvinyl alcohol, hyaluronic

acid, polyethylenimine and their derivatives, and mixtures thereof. Other suitable organic cross-linking agents include monochloracetic acid, sodium CHLOROACETATE, citric acid, butanetetracarboxylic acid and amino acids such as aspartic acid, and mixtures thereof.

The use of a crosslinking agent, especially a diamine or polyamine, some of the processes described in the present invention, can improve the initial value of the absorption capacity under a load of carboxylterminated obtained according to the present invention, compared with the identical in other respects carboxylterminated obtained in a similar process, but without a cross-linking agent. Specifically, carboxylterminated obtained using a cross-linking agent, can have an initial value of the absorption sparough relations carboxylterminated without a crosslinking agent. Identical in other respects carboxylterminated may have the same structure, and can be obtained in exactly the same process as carboxylterminated of the present invention, except that it will not contain a cross-linking agent.

Other suitable crosslinking agents include metal ions with more than two positive charges, such as Al3+, Fe3+Ce3+, Ti4+, Zr4+and Ce4+. Suitable cross-linking agents containing metal ions include those of the transition elements, which usually have vacant d-orbitals. Suitable cross-linking agents, which contain metal ions are AlCl3, FeCl3Ce2(SO4)3, Zr(NH4)4( CO3)4and Ce(NH4)4(SO4)42H2O, other well-known compounds containing metal ions, and mixtures thereof. It is assumed that such cross-linking agents with metal ions used for stitching carboxylterminated form ionic bonds with the carboxyl groups of carboxylterminated. Metal ions with two positive charges, such as Zn2+Ca2+or Mg2+usually do not provide sufficient by the reteni.

A crosslinking agent is usually used in an amount of from 0.01 to 20, preferably from 0.05 to 10 and better from 0.1 to 5 wt.% the total weight of carboxylterminated present in the mixture.

Generally, the order of mixing carboxylicacid, water and cross-linking agent is not a critical factor when using a crosslinking agent. Or carboxylicacid, or a crosslinking agent separately can be added to water and then add the other substances, or all three substances can be added together at the same time. However, it may be preferable, when using some cross-linking agents first add carboxylterminated and water, and then add to the mixture of a crosslinking agent. For example, if the crosslinking agent is used citric acid, may be preferable to carboxylterminated and water were first mixed with each other, and then to the mixture was added citric acid.

In General, catalyst for crosslinking is not necessary, but it may be useful to facilitate the stitching of carboxylterminated of the present invention. For example, if used as a crosslinking agent is citric acid, as to the ü in the amount of from 0.01 to 3 wt.%, better from 0.1 to 1.0 weight. % of the total weight of used carboxylterminated.

An aqueous mixture of carboxylterminated, water, and possibly cross-linking agent generally can be prepared at any temperature at which carboxylterminated soluble in water. Typically, such temperatures are in the range of 10oC to 100oC. As a General rule, the preparation of a mixture of good conduct under stirring.

Water the mixture can be acid /pH less than 7/ neutral /pH equal to 7/ or alkaline /pH greater than 7/. If desired, the mixture can be acidified by adding an aqueous solution of an inorganic acid, such as hydrochloric acid, nitric acid, etc. or an aqueous solution of organic acid such as acetic acid, etc., Similarly, if it is desirable to obtain an aqueous mixture with an alkaline pH, to the mixture you can add a base, such as aqueous solution of sodium hydroxide, potassium hydroxide, ammonia, etc., the pH Value of the water mixture is typically in the range from 2 to 12, preferably from 4 to 9, more preferably from 4 to 7.5 and best of all from 6 to 7.5. Selected carboxylterminated usually has the same pH value as the mixture. However, when carboxylterminated vydelyaetsa is, if the mixture was alkaline.

In the case when carboxylterminated of the present invention is intended for use in products for personal hygiene, such as diapers, training pants, and feminine hygiene, it is normally desirable that carboxylterminated had a neutral reaction. For this reason, it is generally preferable that the water mixture was prepared with a neutral pH. If water mixture after cooking is acidic or alkaline pH, it is allocated from it carboxylterminated may be acidic or alkaline /accordingly/, but can be neutralized. If the selected carboxylterminated is acidic, it can be neutralized, for example by contact with a gaseous base, such as ammonia. If the selected carboxylterminated is alkaline, it can be neutralized, for example, by contacting with an acidic gas such as carbon dioxide.

After preparation of the mixture of carboxylterminated, water, and possibly cross-linking agent, carboxylterminated separated from the mixture. Any way to select carboxylterminated of a mixture, if it does not lead to unacceptable deterioration absorp the AMI such methods are evaporative drying, drying, freezing, precipitation, drying in a critical point, etc.

The selection of carboxylterminated of a mixture here means that almost all the water out from carboxylterminated before additional processing. However, it should be noted that even after removing almost all the water that may remain a small amount of water trapped within the crystal structure of carboxylterminated. The amount of water remaining trapped within a structure of carboxylterminated will typically depend on the method and conditions of allocation of carboxylterminated. Usually remains captured in the selected polysaccharide less than 15 wt.%, preferably less than 10 wt.% and more preferably less than 5 wt.% from the initial amount of water in the mixture.

Preferably carboxylterminated separated from a mixture of evaporative drying. As a General rule, carboxylterminated can be distinguished evaporative drying at a temperature in the range from 10oC to 100oC, preferably from 50oC to 80oC. it is of Course possible to use a higher temperature if the mixture is under pressure. Lower temperatures can be used if the mixture nabilelshami, water and possibly cross-linking agent type precipitator, such as methanol, ethanol or acetone, to plant carboxylterminated from the mixture. Carboxylterminated you can then select filtering. If to highlight carboxylterminated deposition is used, it may be desirable to rinse the selected carboxylterminated to remove the precipitant.

Depending on the form that highlights carboxylicacid, it may be necessary or desirable to change the shape of carboxylterminated. For example, if you use evaporative drying, carboxylterminated can be distinguished in the form of film or sheet. It may be desirable to grind the film or sheet material and turn it into a material consisting of particles or flakes.

The desired shape of the selected carboxylterminated will depend to a large extent on its subsequent use. If carboxylterminated is intended for use in absorbent articles for personal hygiene, it is normally desirable that carboxylterminated was in the form of discrete particles, fibers or flakes. If it is in the form of particles, usually preferably from 100 μm to 1000 μm, more preferably in the range from 300 μm to 600 μm.

Usually isolated from the mixture carboxylterminated must be subjected to heat treatment at an elevated temperature for some time. As a result of this heat treatment is stitching or additional stitching carboxylicacid, which achieves the desired initial AUL value and stability during aging, as described here.

However, if, for example, as a cross-linking agent is used citric acid as catalyst stitching is used hypophosphite sodium, it is possible to obtain carboxylicacid, which has an effective initial AUL value, and improved stability during aging, without subsequent stage of the process, such as heat treatment, after the separation of carboxylterminated from the aqueous mixture.

In General, if heat treatment is required, any combination of temperature and time, which is effective to achieve the desired degree of crosslinking without undesirable damage to carboxylicacid, so that carboxylterminated had the desired initial value AUl and stability during aging, as described here,dialkylphosphate should be subjected to a heat treatment at a temperature in the range from 50 to 250oC, preferably from 80oC, 250oC, more preferably from 100oC to 200oC and better from the 100oC to 160oC. used the higher the temperature, the shorter the period of time normally required to achieve the desired degree of crosslinking. It was found that if you use a very high temperature when the effective duration of treatment, as for example, a temperature of from 200oC to 250oC over time from 50 to 90 seconds can be achieved for carboxylterminated effective initial AUL value and sufficient stability during aging without using a crosslinking agent.

Usually the heat treatment process lasts for a period of time from 1 minute to 600 minutes, preferably from 2 minutes to 200 minutes, and more preferably from 5 minutes to 100 minutes.

If water mixture carboxylicacid, water, and possibly cross-linking agent has an acid reaction, the time required for the implementation of cross-linking can be reduced. We can assume, not counting this assumption is only possible that this is due to the fact that in the slightly acidic environment carboxylterminated will usually contain more free carboxyl is positive low temperature. If water mixture slightly alkaline, there is a tendency to increase the length of the fusion process at a given temperature compared with the weakly acidic and neutral mixture. Despite this, similar to the main absorption properties can be achieved and for acidic and neutral and alkaline aqueous mixture. In some cases it may be desirable to inject water mixture and separate carboxylterminated acid character, in order to reduce the temperature or shorten the heat treatment time. In this case, carboxylterminated can be neutralized after the stage of heat treatment.

As a result of the heat treatment process is carboxylterminated sewn or additionally stitched and is usually swelling in water and insoluble in water. Can be put, not counting this assumption is only possible that as a result of the heat treatment process is to some extent clossiana of carboxylterminated, regardless of the presence of a crosslinking agent, through the formation of ester linkages. This clossiana is in addition to any binding due to the presence of a crosslinking agent. Further, when a crosslinking agent of ammonium salts. Etherification through a process of clossiana occurs primarily in weakly acidic, neutral or slightly alkaline environment. Etherification by clossiana does not proceed in a noticeable extent in a relatively alkaline environment. Crosslinking under the action of a crosslinking agent can occur both in acid and in alkaline medium. Thus, the presence of a crosslinking agent enables the stitching in a wide range of pH.

Usually there is an optimal degree of crosslinking or the number of crosslinks for this carboxylicacid, which provides the optimal initial value of the absorption capacity under load and stability during aging of this modified polysaccharide. If the degree of crosslinking is too low, carboxylterminated may have a relatively low initial value of the absorption capacity under load due to insufficient strength of the gel. If the degree of crosslinking is too high, carboxylterminated may similarly have a relatively low initial value of the absorption capacity under a load due to the inability of carboxylterminated to absorb the liquid.

Experts can be determined by various analytical methods. For example, you can use infrared spectroscopy or nuclear magnetic resonance to determine the presence of the ester or amide cross-linking.

In another aspect, the present invention relates to swelling in water, insoluble in water carboxylicacid, characterized by the fact that this carboxylterminated has stitching formed by the esterification and amidation. This carboxylterminated preferably produced by the methods described above. Despite this, does not mean that the described methods are the only ways by which can be obtained such carboxylterminated.

Testing methods.

Absorption capacity under load. Absorption capacity under load /AUL/ is a test that measured the ability of the absorbent to absorb the liquid /for example, sodium chloride solution in distilled water with a concentration of 0.9 wt.%/, while under the effects of applied load or restraining force.

Device and method for determining AUL will be described with reference to the drawing, which shows the device in perspective during the test. In the drawing until the thorn tripod 4 reinforced spring 5, connected to the sensor 6 a modified thickness, passing through the body 7 of thickness, rigidly mounted on a laboratory stand. Plastic Cup for sample 8, in which the test sample superabsorbent has a bottom permeable to liquid, and placed in a Petri dish 9, which contains absorbed saline solution. The load 10 is placed on top of disk lining /not visible/ that lies on the sample superabsorbent /not visible/.

Cup for sample consists of a plastic cylinder with an inner diameter of 1 inch /2.54 cm/ and an outer diameter of 1.25 inches /3,18 cm/. The bottom of the Cup for sample represents a metal mesh 100 mesh with holes with a diameter of 150 μm, glued to the end of the cylinder by heating grid above the melting temperature of the plastic and cuddling plastic cylinder heated to the grid in order to melt the plastic and attach the mesh to the plastic cylinder.

Modified the thickness gauge is used to measure the expansion of the sample in the absorption solution is a digital auto indicator Mitutoy Digimatic Jndicatic Jndicator, JDC series 543, model 543-180 with the limits of measurement 0 - 0.5 inch and accuracy 0,00005 inch/ firms who by the spring, coupled with the sensor inside the housing. This spring is removed, so that the sensor was able to fall freely, developing when falling down force of about 27, in Addition, also remove the sensor cover, located on the top of the housing of the unit to attach the sensor to the hanging on the tripod spring 5 /received from the company "Mc Master-Garr Supply", Chicago, Illinois, N K/, which serves to counteract or reduce the downward force sensor to a value of 1 g of 0.5, To the upper part of the sensor can be glued to the hook wire to attach a hanging spring. The lower end of the sensor is also equipped with an additional needle /firm "Mitutoyo Corporation", item N 131279/, so that the sensor can be inserted into the Cup for a sample.

To test the sample of absorbent material weight 0,160 g, which was sifted through a sieve so that the particle size ranged from 300 to 600 μm, was placed in a Cup for a sample. The sample was then covered with a plastic disk lining weighing 4.4 g, which had a size slightly smaller than the inner diameter of the Cup for sample and served to protect the sample from damage during the test. Then on top of disk lining placed a weight of 100 g, thus creating a load approximately the intelligent table raised until until it touches the tip of the sensor. The device is set to zero. In a Petri dish pour enough salt solution /50-100 ml/, to start test. The distance rose the cargo in the expansion of the sample as absorbance them salt solution, was measured using the sensor. This distance is multiplied by the square internal cross-section cups for sample, is a measure of the increase in the volume of the sample in the absorption. Multiplying this value by the density of the salt solution and knowing the weight of the sample, it is easy to calculate the amount of the absorbed salt solution. The weight of saline solution absorbed after 60 min, gives the value of AUL>, expressed in grams of saline solution absorbed per gram of absorbent. If desired, the testimony of modified thickness can be continuously entered into the computer /Mitutoyo Digimatic Miniprocessor AL-DH/ in order to make calculations and to obtain values AUL. To control the AUL value can also be determined by measuring the difference in weight of the Cup to the sample before and after the test, and this difference in weight will correspond to the amount of solution absorbed by the sample.

Examples.

Example 1.

Used DV is Cellulosa resin CMC-7HCF or CMC-9H4F. Carboxymethylcellulose CMC-7HCF had an average degree of substitution of about 0.7 and a viscosity of 1% aqueous solution at 25oC about 1000-2800 CP. CMC-9H4F had an average degree of substitution of about 0.9 and a viscosity of 1% aqueous solution at 25oC about 2500-6000 CP. Each type of carboxymethylcellulose separately dissolved in distilled water to obtain a solution containing 2 wt.% of carboxymethyl cellulose to the total weight of the solution. A crosslinking agent was dissolved in water, obtaining a solution containing 0.5 wt.% a crosslinking agent to the total weight of the solution. As cross-linking agents used chitosan glutamate produced by the firm "Protan Biopolymer A/S, Norway under the trade name "SeQ Cure G; 1,4-butyleneglycol manufactured by the firm Aldrich Chemical Co"; polyethylenimine /molecular weight 50000-100000/ produced by the firm "Polysciences"; the sodium salt of hyaluronic acid produced by the company "Sigma"; gelatin type a, manufactured by the firm Aldrich Chemical Co. under the trade name 300 Bloom; and Diethylenetriamine manufactured by the firm Aldrich Chemical Co. An aqueous solution containing a crosslinking agent was then added to each of the aqueous solutions containing the carboxymethyl cellulose to obtain different concentrations of crosslinking agent relative to the total is ethylcellulose and a crosslinking agent, then thoroughly mixed. The carboxymethyl cellulose was isolated from the solution by evaporative drying at 80oC in an air dryer Blue M. After drying dedicated carboxymethylcellulose were crushed into granules in the mixer and subjected to heat treatment at different processing times and at different temperatures in the furnace. Experiments were conducted with different combinations of carboxymethylcellulose, cross-linking agent, various concentrations of cross-linking agent, the temperature of the heat treatment and the duration of heat treatment. We measured the initial value of the absorption capacity under load for different samples of carboxymethyl cellulose, treated in this way. Quantitative data on each combination of carboxymethyl cellulose and cross-linking agent and their initial AUL value shown in table. 1. Similar values were determined AUL for the control samples of carboxymethylcellulose CMC-7F and SMS 94F. These results are also shown in table. 1.

As you can see from the data table. 1, the method proposed in the present invention significantly increases the initial value of the absorption capacity under load the source karboksimetilcellyulozih is osobnosti under load. In addition, it is seen that the cross-linking agents are effective in the entire concentration range.

Example 2.

An aqueous solution of chitosan glutamate, used in example 1 is slightly. In order to evaluate the effect of pH, used a crosslinking agent with the basic properties of Diethylenetriamine manufactured by the firm Aldrich Chemical Co/. As in the previous example, carboxymethyl cellulose /CMC-7F/ dissolved in water, getting water solution with a concentration of 2 wt.%. Diethylenetriamine was dissolved in water, getting water solution with concentration of 0.5 wt.%. Then an aqueous solution of Diethylenetriamine was added to aqueous solution of carboxymethyl cellulose to obtain a concentration of Diethylenetriamine 2 wt.% the total weight of carboxymethyl cellulose, present in aqueous solution. The carboxymethyl cellulose was then isolated by evaporative drying, and crushed into a powder as described in example 1. Material for comparison prepared by dissolving the carboxymethyl cellulose /CMC-7HCF/ in distilled water to obtain a solution with a concentration of 2 wt.%. To the aqueous solution of carboxymethyl cellulose was then added of 0.004 wt.% of sodium hydroxide. Carboxymethylcellulose prepared for comparison, were isolated and smiljanich polymers was determined by the initial absorption capacity under load. The results of determination are shown in table. 2.

As you can see from the table. 2, carboxymethylcellulose without cross-linking agent in an alkaline environment does not show any increase in the initial values of the absorption capacity under load after heat treatment. In contrast, it is seen that for carboxymethylcellulose containing a crosslinking agent with the Foundation properties, Diethylenetriamine, the initial AUL value increases as a result of heat treatment. You can put, this indicates that clossiana carboxymethylcellulose at a relatively alkaline pH occurs with difficulty.

Example 3.

Samples NN 65-71 received, preparing an aqueous solution containing 2 weight. % of carboxymethyl cellulose /CMC-7F/. To the water solution was added amount of sodium hydroxide sufficient to bring the pH of the solution to 9. The solution was no cross-linking agents. Then the carboxymethyl cellulose according to the method described in example 1, was isolated, crushed, subjected to heat treatment at 150oC for different periods of time, and determine the absorption capacity under load.

Samples NN 72-77 received, preparing an aqueous solution containing 2 weight. % of carboxymethyl cellulose /CMC-NS is, what is the pH of the solution was 7.4. Then the carboxymethyl cellulose according to the method described in example 1, was isolated, crushed, subjected to heat treatment at 150oC for different periods of time and determine the initial value of the absorption capacity under a load.

Samples NN 78-103 was obtained in the same manner as the samples NN 72-77, except that the aqueous solution containing carboxymethylcellulose and chitosan glutamate, prior to extraction was added sodium hydroxide. The amount of added sodium hydroxide sufficient to bring the pH to 9.2, 10.1 or 10,9. Then the carboxymethyl cellulose according to the method described in example 1, was isolated, crushed, subjected to heat treatment at 150oC for different periods of time and determine the initial value of the absorption capacity under a load.

The results of these tests /samples NN 65-103/ are given in table. 3.

As you can see from the table. 3, alkali carboxymethylcellulose containing no cross-linking agent /samples 65-71) does not show a noticeable increase in the initial values of the absorption capacity under load in the heat treatment. In contrast, samples 7-103 shows what imitatie initial values of AUL, less than at high pH.

Example 4.

Used carboxymethyl cellulose, manufactured by the firm "Agualon Company under the trade name "cellulose resin Agualon CMC-7L. The carboxymethyl cellulose has a relatively low molecular weight, which corresponds to a viscosity of 2% aqueous solution at 25oC for about 25 to 50 CP. Sample 104 N /comparative/ was obtained by preparing an aqueous solution containing 2 wt.% carboxymethyl cellulose /CMC-7L/. The carboxymethyl cellulose was isolated and dried as described in example 1. It was found that this material had an initial value of the absorption capacity under a load of 2.1. Sample 105 N /comparative/ received a similar pattern N 104, except that after extraction of this material was ground and subjected to heat treatment at 170oC for 160 minutes. The resulting material had an initial value of the absorption capacity under a load of 8.6. Neither the material does not contain a crosslinking agent.

Sample N 106 was obtained by preparing an aqueous solution containing 2 weight. % of carboxymethyl cellulose /CMC-7L/. To the water solution was added 1 weight. % chitosan glutamate, in the same manner as described in example 1. Then karpooravalli for two hours at 170oC. it Was found that the resulting material has an initial value of the absorption capacity under a load equal to 14.7.

From the above it is seen that the presence of a crosslinking agent is chitosan glutamate significantly improves the initial value of the absorption capacity under load for low molecular weight carboxymethyl cellulose compared to materials not subjected to heat treatment and materials, heat treated, but not containing a cross-linking agent.

Example 5.

To determine behavior during aging absorbents obtained in accordance with the present invention and comparative samples absorbents were prepared with the following samples:

Sample N 107 was obtained similarly to the sample N 2.

Sample N 108 received the same N samples 25-28, except that the material was heated at 150oC for 70 minutes.

Sample N 109 was obtained similarly to sample No. 42. Were obtained from different initial AUL value.

Sample No. 110 was obtained similarly to the sample N 24, except that the material was heated for 20 min.

Sample # 111 received by the method specified in example 1, using ethylene glycol in kazzy NN 107-111 were placed in conditions of controlled temperature and humidity. Maintained the temperature of the 24oC and relative humidity 30%. For the samples was determined AUL value at different points within 60 days. The results are shown in table. 4. In the table, the value of "saving AUL indicate the AUL value after 60 days, expressed as a percentage of the value AUL in 0 days /initial AUL value. That is the AUL value after 60 days divided by the value of the AUL for 0 days.

As can be seen from table 4, although only one heat treatment, in the absence of a crosslinking agent gives acceptable initial AUL value, saving AUL after 60 days is only 34,5% /sample 107 N/

Adding a cross-linking agent in accordance with the present invention provides improved retention of the AUL value after 60 days /samples NN 108-111/.

Example 6.

In this example evaluated the use of polyvalent metal ions as cross-linking agents. The carboxymethyl cellulose was dissolved in distilled water, getting solutions containing 2 wt.% of carboxymethyl cellulose to the total weight of the solution. A crosslinking agent containing a metal ion, dissolved in water, obtaining a solution. Then an aqueous solution containing a crosslinking agent based on the metal ion was added to separate the cross-linking agent relative to the total weight of carboxymethyl cellulose, present in the solution. The mixture containing water, carboxymethyl cellulose and cross-linking agent, and then thoroughly mixed. The carboxymethyl cellulose was isolated from the solution by evaporative drying at a temperature of from 30oC to 50oC. After drying, the selected carboxymethylcellulose were crushed and sieved through a sieve, obtaining granules ranging in size from 300 to 600 μm. These pellets are then subjected to heat treatment for different time and at different temperatures in the furnace. They conducted experiments with different combinations of carboxymethylcellulose, cross-linking agent on the basis of metal ions at different concentrations of cross-linking agent, the temperature and heat treatment time of the heat treatment. We measured the initial value of the absorption capacity under load, and changing properties during aging for different samples of carboxymethyl cellulose. Tests on the change of properties during aging was carried out at ambient temperature 23oC and relative humidity from 30% to 60%. Quantitative data about the ratio of carboxymethyl cellulose and cross-linking agent and the magnitude of the AUL listed in the table. 5. Likewise determined AUL values for the control samples carboxy is 114 and placed in conditions with controlled temperature and humidity. Maintained a temperature of about 23oC and relative humidity of about 100%. For the samples was determined AUL value at different points in time during aging. The results are shown in table. 6.

The carboxymethyl cellulose /Agualon CMC-7H4F/ was dissolved in distilled water, preparing a solution with a concentration of 2 wt.%, and stirred by means of an industrial mixer Hobart when the stirring speed from low to medium. To the solution were added various amounts of carbonate, ammonium zirconium /Outlook addon/. The solution is evaporated at 50oC during the night in the conventional dryer. After crushing and sieving through a sieve the samples was determined values of AUL in the absence of additional heat treatment /time additional heat treatment 0 minutes/. For additional stitching samples used additional heat treatment /hardening/ at a temperature of 110oC for different periods of time. After that, the samples were again determined values of AUL. The results are shown in table. 7.

The carboxymethyl cellulose /Adualon CMC-7H4F/ was dissolved in distilled water to obtain solutions with a concentration of 2 wt.%, and stirred by means of an industrial Hobart mixer at speed paramesh the ones on the weight of carboxymethyl cellulose. For sample 142 to the solution was added 1 wt.% carbonate of ammonium zirconium, based on the weight of carboxymethyl cellulose. A sample of 133 were dried at 50oC for two days in a convection dryer. Samples 134-135 were dried at 50oC for four days in a convection dryer. Samples 136-141 was dried at 80oC for four days in a convection dryer. A sample of 142 was dried at 80oC for two days in a convection dryer and then subjected to heat treatment for 20 minutes at 80oC. After grinding and sieving through a sieve, the samples were placed in an environment with controlled temperature and humidity. Maintained a temperature of about 23oC and relative humidity of about 100%. For the samples was determined AUL values at different points in time during aging. The results are shown in table. 8.

The carboxymethyl cellulose obtained from pulp obtained in the Kraft process of Northern hardwoods, which used sodium hydroxide to the alkali treatment after bleaching; and where the pulp had a viscosity of about 43 CP and a degree of polymerization /srednecenovogo/ about 2023; and where the carboxymethyl cellulose had a degree of substitution in the range of 0.7 to 0.9 dissolved is sites Hobart when the stirring speed from low to medium. To the solution was added to the ferric chloride /0.6 wt.% based on the weight of CMC/. The solutions were dried over night at 80oC in a convection dryer. After crushing and sieving through a sieve the samples was determined values of AUL. For additional crosslinking of the samples was applied subsequent heat treatment at a temperature of 140oC for different periods of time. The samples were again determined values of AUL. The results are shown in table. 9.

Sample N 144 is a material of the table. 9, where CMC was subjected to heat treatment at a temperature of 140oC for 25 minutes Sample of N 145 is a material of the table. 9, where CMC was subjected to heat treatment at a temperature of 140oC for 30 minutes the samples were placed in an environment with controlled temperature and humidity. Maintained temperature of approximately 23oC and relative humidity of about 100%. The samples were determined AUL value at different points in time during aging for 20 days. The results are shown in table. 10.

The carboxymethyl cellulose was dissolved in distilled water to obtain solutions with a concentration of 2 wt.%, and stirred by means of an industrial Hobart mixer at speed paramashiva is ovali carboxymethylcellulose, similar to the one you made for further processing to obtain the pattern shown in the table. 9. To the solution were added various amounts of sulfate trivalent cerium. The solutions were dried at 80oC overnight in a convection dryer. After grinding and sieving through a sieve the samples was determined values of AUL. For additional stitching samples used additional heat treatment at a temperature of 140oC for different periods of time. After that, the samples were again determined values of AUL. The results are shown in table. 11.

Sample N 149 is a material of the table. 11 at a weight ratio of CMC/CE2(SO4)3from 100 to 1, where SMS was subjected to heat treatment at a temperature of 140oC for 60 min, the sample was placed in an environment with controlled normal conditions - a temperature of about 23oC and relative humidity from 30% to 60%. For the sample was determined by AUL value at different points in time during the 11-month period. The results are shown in table. 12.

Sample N 150 represents a carboxymethyl cellulose Agualon SMS 74F, to which was added a crosslinking agent. Sample N 151 is a material from a temperature of 140oC for 50 minutes Sample N 152 is a material of the table. 11, where the weight ratio of CMC/CE2(SO4)3is 100/1 and where CMC was subjected to heat treatment at a temperature of 140oC for 100 minutes These samples were placed in an environment with controlled temperature and humidity. Maintained temperature of approximately 23oC and relative humidity of about 100%. For the samples was determined AUL value at different points in time during aging. The results are shown in table. 13.

Example 7.

The carboxymethyl cellulose /Agualon CMC-7H4F/ was dissolved in distilled water to obtain solutions with a concentration of 3 weight. % and stirred by means of an industrial mixer Waring, who worked at low speed. To the solution were added various amounts of acids based on the weight used CMC. The solutions were poured into trays with Teflon coating and dried at 75oC overnight in a convection dryer. After crushing and sieving through a sieve the samples was determined values of AUL. The results are shown in table. 14.

Additional samples, where as crosslinking additives used monochloracetic acid /MSAA/, prepared by the same method, which was spoliators and humidity. For samples 170 and 171 kept the temperature around 23oC and relative humidity of about 100%. For samples 172 and 173 maintained a temperature of about 110oF /about 43oC/ and a relative humidity of about 80%. For samples 174 and 175 maintained a temperature of about 23oC and relative humidity under normal conditions - from 30% to 60%. For samples determined the size of AUL at 0.3 psi /0,021 kg/cm2/ and different points in time during aging. The results are shown in table. 15.

Various amounts of acetic acid was added to the water to achieve the desired pH. The carboxymethyl cellulose /Agualon CMC-7H4F/ was dissolved in acidified water to obtain solutions of CMC with a concentration of 3 wt.%, and stirred by means of an industrial mixer Waring, who worked at low speed. After the CMC were completely dissolved in acidified water, measured the pH of the mixture. This pH value shown in table. 16. The solutions were poured into trays with Teflon coating, dried at 40oC overnight in a convection dryer and then crushed and sieved through a sieve. For additional stitching samples used heat treatment at different temperatures and for different periods of greenarmadillo Agualon CMC-7H4F, and perform heat treatment at 140oC for 90 min, and the ageing conditions were as follows: temperature 23oC and relative humidity from 30% to 60%. For samples 181-182 used carboximetilzellulozu Agualor SMS 7F, heat treatment was carried out at 100oC for 120 min for sample 181 and at 150oC for 35 min for sample 182, and the ageing conditions were as follows: temperature of approximately 23oC and relative humidity from 30% to 60%.

Example 8.

The carboxymethyl cellulose /Agualon CMC-7H4F/ was dissolved in distilled water to obtain solutions with a concentration of 2 wt.%, and stirred by means of an industrial Hobart mixer at low to medium speed mixing. To the solution were added various amounts of aspartic acid /AA/. The solutions were dried at 80oC overnight in a convection dryer. After crushing and sieving through a sieve for the samples was determined values of AUL, at a load of 0.3 psi/cm2/. For additional crosslinking of the samples was applied heat treatment at a temperature of 140oC for different periods of time. After this treatment, the samples were again identified the AUL value at a load of 0.3 psi. The results given Argunova acid/SMS equal to 2.5/100, where CMC was subjected to heat treatment at a temperature of 110oC for different periods of time. For the samples was determined AUL value at a load of 0.3 psi after heat treatment. The results are shown in table. 18.

Sample N 189 is a material from table 18, where CMC was subjected to heat treatment at a temperature of 110oC for 10 min Sample N 190 is a material of the table. 18, where CMC was subjected to heat treatment at a temperature of 110oC for 15 min Sample N 191 is a material of the table. 18, where CMC was subjected to heat treatment at 110oC for 20 min Sample N 192 represents a control material, where the CMC has not added aspartic acid and where CMC was subjected to heat treatment at a temperature of 140oC for 30 minutes the samples were placed in an environment with controlled temperature and humidity. Maintained a temperature of about 23oC and relative humidity of about 100%. For samples determined the size of AUL, at a load of 0.3 psi, at different points in time during aging. The results are shown in table. 19.

Example 9.

The carboxymethyl cellulose /Aualon CMC-7H4F/was dissolved in distilled water to obtain a solution with a concentration of 2 wt.%, and mixed in the mixer from stainless steel, the agent and hypophosphite sodium /SHP/ as a catalyst for crosslinking. The solutions were well mixed at 25oC, was poured into the pans with Teflon coating and dried at 95oC for 16 h in a convection dryer. After crushing and sieving through a sieve to separate the fraction with a particle size of from 300 to 600 μm, was determined for samples of size AUU at a load of 0.3 psi. The results are shown in table. 20.

Samples 196, 197, and 199 were placed in an environment with controlled temperature and humidity. Maintained a temperature of about 25oC and relative humidity of about 100%. For the samples was determined AUL value at a load of 0.3 lb/sq, inch at different points in time in the course of aging. The results are shown in table. 21.

Example 10.

To obtain samples of the carboxymethyl cellulose used conventional synthetic scheme of the suspension process, which in General can be described as follows: 15 g of cellulose was placed into a 400 ml isopropanol in a reactor equipped with a mechanical stirrer, an inlet for entry of inert gas and a sensor for temperature control. Then he added thirty-five milliliters of water containing the desired amount of alkali/. The suspension was stirred for half an hour at room temperature (about 23oC THE 60oC. Then the suspension was filtered, the product washed twice with a mixture /400 ml/ methanol and water 70:30 /volume/ off, washed once with 400 ml of methanol and dried. Dedicated carboxymethyl cellulose was then dispersible in water, dried at 30oC and crushed into granules. Selected fraction with a particle size of from 300 to 600 microns to determine the absorption capacity. The degree of substitution in the obtained carboxymethyl cellulose was measured by the method of1H-NMR spectroscopy. Morphological features of the dispersion of carboxymethyl cellulose was observed using a polarizing optical microscopy and x-ray diraction processes. Tests to determine AUL was conducted at a load of 0.3 psi. Tests on aging was carried out by placing granular samples in a chamber filled with steam /relative humidity of 100% at room temperature (about 24oC/. Through certain time intervals samples were removed from the chamber and dried under normal ambient conditions for two days before testing the absorptive capacity. Unused samples were placed back in the camera to continue aging.

For the following samples use the mole Aqualon CMC-7H4F specified under the designation CMC-74F. The pulp manufactured by ITT Rayonier Corp., under the trade name Porosanier-I, which is a wood pulp from southern pine with a characteristic viscosity of about 8.4 DL/g and a content of alpha-cellulose 98,7%, are listed under the designation 1TT. The pulp produced by the company "Southern Cellulose Products under the trade name Grade 1050, representing cellulose from cotton pickings, with the content of alpha-cellulose of about 99.2%, and are listed under the designation SC. The pulp obtained by the Kraft process without cold alkali treatment after bleaching with a viscosity of about 15,3 CP and the content of alpha-cellulose of about 94.6% of that specified under the designation CR# 8. The pulp obtained by the Kraft process from wood pulp softwood southern species that use sodium hydroxide for cold alkali treatment after bleaching, having a viscosity of about 19.8 CP and a degree of polymerization /srednecenovogo/ ABT 1477 specified under the designation CR# 10. The pulp obtained by the Kraft process from softwood southern rock, which used sodium hydroxide to cold alkali treatment after bleaching with a viscosity of approx. 16,6 CP and a degree of polymerization of the /among the of aspen chips without cold alkali treatment after bleaching, having a viscosity of about 41.2 CP and a degree of polymerization /srednecenovogo/ about 1997, listed under the designation CR#18. The pulp used to produce sample 143 table. 9, are listed under the designation CR#21.

For comparison, the synthesized samples of water-soluble carboxymethylcellulose. In table. 22 shows the reaction conditions and the magnitude of absorption of the samples. All samples soluble in saline solution, used for testing, and AUL values determined for samples aged at ambient temperature (about 24oC/ and at a relative humidity of about 100%.

Prepared samples, using as alkali potassium hydroxide /KOH/. In table. 23 given reaction conditions and amount of absorption of the samples. All samples under dispersion in water to give a translucent and fiber dispersion.

As you can see, for example, from the comparison of samples 207 and 212, using potassium hydroxide instead of sodium hydroxide leads to the production of carboxymethyl cellulose, which has a high initial value of the absorption capacity under load, and good stability during aging.

Samples 213 and 214 received, use the acid, less than 2: 1. Samples 215-222 was obtained with the use of a smaller quantity of the modifying agent, as shown molar ratio of Chloroacetic acid to cellulose, which is less than 1:1.

In table. 24 given reaction conditions and amount of absorption of the samples.

Samples 208 and 214-217 also placed in an environment with controlled temperature and humidity. Maintained the temperature of the 23oC and relative humidity of about 100%. For the samples was determined AUL value at a load of 0.3 psi at different points in time in the course of aging. The results are shown in table. 25.

Example 11.

The carboxymethyl cellulose /Aqualon CMC-7H4F/ was dissolved in distilled water to obtain solutions with a concentration of 2 wt.%, and mixed them with industrial mixer Habart, operating at low to medium speed mixing. The solutions were dried at 80oC overnight in a convection dryer, and then the dried product was ground and sieved through a sieve. For stitching samples were used for subsequent heat treatment at a temperature of 226oC for different periods of time. These samples were placed in an environment with controlled temperature and VL is supported temperature of 25oC and relative humidity of about 100%. For samples determined the size of AUL, at a load of 0.3 psi at different points in time in the course of aging. The results are shown in table. 26.

Although the present invention is described through specific methods of implementation described above, the experts in this field will understand the many possible equivalent changes and modifications of the invention. Accordingly, the specific examples above do not imply in any way limit the scope of this invention as set forth in the accompanying claims.

1. The method of obtaining swelling in water, not soluble in water carboxylicacid, comprising the following stages: preparation of a homogeneous mixture consisting of water-soluble carboxylterminated and water, where carboxylterminated soluble in water; the selection of the specified carboxylterminated of the above-mentioned mixture and heat treatment specified selected carboxylterminated at a temperature of 200 - 250oC for 50 - 90 s, and this heat treatment leads to a more efficient binding of the specified carboxylterminated and specified rastvorimy in water carboxylterminated has an initial value of the absorption capacity under load of at least about 17 g/g and retains at least about 5% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least 30%.

2. The method according to p. 1, where carboxylterminated obtained from polysaccharide selected from the group consisting of cellulose, starch, guar, carrageenan, agar, Gellan resin, chitin, chitosan and mixtures thereof.

3. The method according to p. 1, where carboxylterminated is carboximetilzellulozu.

4. The method according to p. 2, where carboxylterminated is carboxymethyllysine.

5. The method according to p. 4, where carboxymethyllysine is a carboxymethylcellulose.

6. The method according to p. 1, where the specified carboxymethyllysine allocate by evaporative drying.

7. The method according to p. 1, where the pH of this mixture containing the specified carboxylterminated and water is in the range from 5 to 9.

8. The method according to p. 1, where swelling in water, not soluble in water carboxylterminated has an initial value of the absorption capacity under load of at least about 20 g/g

9. The method according to p. 1, where swelling in water, not soluble in water carboxylterminated retains at least about 70% of the initial value of the absorption capacity under load after the p. 1, where swelling in water, not soluble in water carboxylterminated retains at least about 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of 100%.

11. The method of obtaining swelling in water, not soluble in water carboxylicacid, comprising essentially the following stages: preparation of a homogeneous mixture consisting essentially of water-soluble carboxylterminated and water, where water-soluble carboxylterminated soluble in water; adding to the homogeneous mixture solution consisting essentially of a cross-linking agent containing aluminum ion, dissolved in water, the selection of the specified carboxylterminated and specified cross-linking agent of the above-mentioned mixture, with swelling in water, insoluble in water carboxylterminated has an initial value of the absorption capacity under load of at least about 17 g/g and retains at least about 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least 30%.

12. The method according to p. 11, where carboxy ainana, agar, Gellan resin, chitin, chitosan and mixtures thereof.

13. The method according to p. 11, where carboxylterminated is carboximetilzellulozu.

14. The method according to p. 11, where carboxylterminated is carboxymethyllysine.

15. The method according to p. 14, where carboxylterminated is a carboxymethylcellulose.

16. The method according to p. 11, where the specified carboxylterminated and the specified crosslinking agent allocate by evaporative drying.

17. The method according to p. 11, where swelling in water, not soluble in water carboxylterminated has an initial value of the absorption capacity under load of at least about 20 g/g

18. The method according to p. 11, where swelling in water, not soluble in water carboxylterminated retains at least about 70% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least 30%.

19. The method according to p. 11, where swelling in water, not soluble in water carboxylterminated retains at least about 50% of the initial value of the absorption capacity under load after aging for 60 semoga in water carboxylicacid, includes: a) preparation of the reaction dispersion comprising a solvent and a polysaccharide that contains the original crystal structure; (b) adding carboxyaniline agent to the reaction dispersion under conditions effective for reaction carboxyaniline reagent with the polysaccharide to obtain soluble in water, dispersible in water carboxylicacid; (c) the selection is not soluble in water, dispersible in water carboxylterminated from the reaction dispersion; (d) preparation of a mixture consisting of selection is not soluble in water, dispersible in water carboxylterminated and water, and (e) the allocation of carboxylterminated from the mixture, thus carboxylterminated contains so many of the original crystal structure of the polysaccharide, which is effective to get carboxylicacid, swelling in water and not soluble in water, which has an initial value of the absorption capacity under load of at least about 17 g/g and retains at least about 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least consisting of cellulose, chitin, and mixtures thereof.

22. The method according to p. 20, where carboxylterminated is carboximetilzellulozu.

23. The method according to p. 20, where carboxylterminated is carboxymethyllysine.

24. The method according to p. 23, where carboxylterminated is a carboxymethylcellulose.

25. The method according to p. 20, where the specified carboxylterminated isolated from the mixture by evaporative drying.

26. The method according to p. 20, where swelling in water insoluble in water carboxylterminated has an initial value of the absorption capacity under load of at least about 20 g/g

27. The method according to p. 20, where swelling in water insoluble in water carboxylterminated retains at least about 70% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least 30%.

28. The method according to p. 20, where swelling in water insoluble in water carboxylterminated retains at least about 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of 100%.

30. The method according to p. 20, where to get carboxylterminated used the ratio of alkali to carboxyethylidene the reagent is less than the stoichiometric ratio.

31. The method according to p. 30, where the ratio of alkali to carboxyethylidene the reagent is less than 2:1.

32. The method according to p. 20, where in the reaction molar ratio carboxyaniline reagent to the polysaccharide is less than 1:1.

33. The method according to p. 32, where carboxyaniline reagent is a Chloroacetic acid and the polysaccharide is a cellulose.

34. The method of obtaining swelling in water, not soluble in water carboxylicacid, comprising: (a). preparation of a mixture consisting of water-insoluble, dispersible in water carboxylterminated and water, and (b) the allocation of carboxylterminated of a mixture, where carboxylterminated obtained from polysaccharide that contains the original crystal structure, and carboxylterminated contains so many of the original crystal structure of the polysaccharide, which is effective for obtaining swelling in water and not soluble in water carboxylicacid, and selected carboxylterminated is th least about 50% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least 30%.

35. The method according to p. 34, where carboxylterminated obtained from polysaccharide selected from the group consisting of cellulose, chitin, and mixtures thereof.

36. The method according to p. 34, where carboxylterminated is carboximetilzellulozu.

37. The method according to p. 34, where carboxylterminated is carboxylterminated.

38. The method according to p. 37, where carboxylterminated is a carboxymethylcellulose.

39. The method according to p. 34, where the specified carboxylterminated isolated from the mixture by evaporative drying.

40. The method according to p. 34, where swelling in water, not soluble in water carboxylterminated has an initial value of the absorption capacity under load of at least about 20 g/g

41. The method according to p. 34, where swelling in water, not soluble in water carboxylterminated retains at least about 70% of the initial value of the absorption capacity under load after aging for 60 days at 24oC and a relative humidity of at least 30%.

42. The method according to p. 34, where swelling in water, not soluble in water carboxycellulose the program within 60 days when the 24oC and a relative humidity of 100%.

43. Swelling in water, not soluble in water carboxylterminated obtained by the method described in paragraph 1.

44. Swelling in water, not soluble in water carboxylterminated obtained by the method described in paragraph 11.

45. Swelling in water, not soluble in water carboxylterminated obtained by the method described in paragraph 20.

 

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