The gel (and its variants)

 

(57) Abstract:

Describes a gel containing water, sodium ions, calcium ions and alginate, wherein the gel further comprises Gellan gum and prescribe and in which the ratio of sodium ions to calcium ions is between about 15:1 to about 45:1, the amount of alginate is about 0.3 - 4 wt. %, the amount of Gellan gum is approximately 0.05 - 4 wt.% and the number of sequestrant is about 0.01 to 1.5 wt.%. The technical result - the formation of diffusion-destructuring gels adding water types, with a high concentration of sodium ions. 2 S. and 2 C.p. f-crystals, 1 table.

The invention relates to a gel (its variants).

The alginate used for many years as a gelling in puddings, fruit fillings, berries or fruits in jelly and structured food products, as water binders, frozen foods, syrups, toppings flour confectionery and glazes, as an emulsifier in the seasonings to the salad and meat, giving the taste and aroma of sauces and as a stabilizer in beer, fruit sauce, decorations on the top powerknowledge cations, including cations of zinc, aluminum, copper and calcium, forming gels or precipitates. Well it is also known that the viscosity of solutions of sodium alginate change by the addition of salts of monovalent metals, but that this salt does not induce the formation of gel.

Known gel containing water, sodium ions, calcium ions and alginate (Derwent Publications Ltd., London, GB AN 124986, week 8220-JP59-063147 A, CL A 23 K 1/18, 1984).

Known gel containing water, sodium ions, calcium ions and Gellan gum (Research Disclosure, 350, 1 June 1993, Havant JB, p. 35081 XP 000373023, W. F. Chalupa et al., "Gellan gum Coating and Adhesion Systems", page 418 3rd paragraph).

The applicant has unexpectedly been found that solutions of alginates is actually really form detrusion-nestrukturirovannye gels adding water certain types, such as sea water having a high concentration of sodium ions.

The invention is a gel containing water, sodium ions, calcium ions and alginate, wherein the gel further comprises Gellan gum and prescribe and in which the ratio of sodium ions to calcium ions is between about 15:1 and about 45:1, the amount of alginate is between about 0.3 and 4%, the amount of Gellan gum is between prima is about the alginate is between about 0.7 and 2%, the amount of Gellan gum is between about 0.2 and 1%, and the number of sequestrant is between about 0.01 and 1.5 per cent.

Even more preferably the amount of alginate is between about 0.7 and 2%, the amount of Gellan gum is about 0.2 and 1%, and the number of sequestrant is between approximately 0.05% and 0.6%.

Even more preferably the alginate contains mannurone acid and guluronate acid in a mass ratio between about 2:1 and 0.35:1.

Another object of the invention is a gel containing water, sodium ions, calcium ions, and Gellan gum. The novelty is that the gel further comprises prescribe and the balance of sodium ions to calcium ions is between about 15:1 and about 45:1, number of Gellan gum is between about 0.05 and 4% and the number of sequestrant is between about 0.01 and 1.5 per cent.

Gellan gum is heteropolysaccharides obtained by fermentation using Pseudomonas elodea ETCC 31461. Gellan gum available from Kelco Division of Merck and Co., Inc., San Diego, Canada, under different names, including KELCO-GEL, KELCOGEL PC and KELCOGEL F. Methods of obtaining Gellan gum include the methods described in abilitiesa and film-forming applications, in particular as gelling agents in food products, products for personal use, and industrial applications.

Gellan gum is gelling and texturous tool that forms gels in the presence of ions. Unlike other gel-forming means Gellan gum capable of forming gels with everyone present ions including hydrogen ions. Gels can be conveniently obtained by keeping the hot solution to cool. Less common, but sometimes a useful way is to obtain a gel by diffusion of ions in the solution. This method is used, for example, in the formation of films and coatings, for example, liquid coating and similar edible coatings. Especially valuable in these coatings is the ability'gellan to form gels with sodium ions. Thus, the sodium chloride can be used as a source of gelling ions produced foods retain a pleasant taste, it can be used sometimes with other ions, but not the ions, such as calcium, which can give a bitter taste.

As a result of these properties, solutions of Gellan gum in addition to containing a high concentration of ions nutrito can be used advantageously in various applications, including, but limited to, the above-described application.

Commercial forms of Gellan gum, an anionic polymer is obtained in the form of mixed salts. Although gum in the overwhelming number is in the form of potassium salt, usually there is a sufficient amount of divalent ions such as calcium and magnesium, to make the product insoluble in cold water. The solubility is further eroded if the water in which the gum is necessary to dissolve or hydrate, also contains ions. This is to be expected, since, if ions are able promote cross-links Association (gelation), they will also prevent cross-links dissociation (liquefaction).

The dissolution of Gellan gum in cold water can usually be achieved simply by removing divalent ions in the water by use of sequestrant. Divalent ions are much more effective at getting gels than monovalent ions, and therefore the destruction of the first sequestrants usually leads to the aquatic environment, in which the soluble gum. Prescribe not only removes divalent ions from the water, but also bivalent ions of Gellan gum, making it soluble in cold water form odnomomentno the R sodium hexametaphosphate, the pyrophosphate is tetranitride, secondary acid sodium orthophosphate and sodium tripolyphosphate. You can also use sodium citrate.

The presence of three types of polymer segments in alginic acid from different brown algae was shown mild acid hydrolysis. One segment consists essentially of the components of the D-mannurone acid. The second segment consists essentially of the components of the L-guluronic acid. The third segment consists of alternating residues of D-mannurone acid and L-guluronic acid.

The relative content of the three polymer segments in the samples of alginic acid from different sources were identified using partial acid hydrolysis to separate alginic acid homopolymer and alternative segments. The relative content segments polymannuronic acid and prigorodovoy acid was determined by NMR spectroscopy. Table 1 shows the relative content mannurone acid and guluronic acid in samples of alginic acid obtained from different brown seaweeds.

Prigorodova acid is a folded like a ribbon molecule, in which gourova acid is in the polar hydrogen bond between the hydroxyl group at carbon atom 2 and the oxygen atom of hydroxyl group in the neighboring links. Intermolecular bonds are more complicated than in the case of polymannuronic acid, and include water molecules. The water molecule is in such position that it works twice as donor hydrogen bonds and twice as acceptor, and educated thus hydrogen bonds are in the range of 2.7 to 2.9 A. In accordance with the data density measurement and to maintain symmetry in the unit cell requires four molecules of oxen.

One of the most important and useful properties of alginate is its ability to form gels by reaction with calcium salts. These gels, which are similar to solids in the ability to retain the shape and resistance to voltage, are almost 100% of water (usually a 99.0-99.5% and 0.5 to 1.0% alginate).

Gel classical colloidal terminology is defined as the system, which owes its characteristic properties stitched spatial grid of polymer chains, which is formed at the point of gelation. A significant number of studies have been conducted to explain the nature of the crosslinks and define the structure of alginate gels.

Based on the diffraction of fibers, calculations for building models Euronaval acid alginic acid such tape and stretched. On the basis of these data and properties of the gels was supposed to be cooperative Association segments prigorodovoy acid involved in the formation of crosslinked spatial network of polymer chains. Common proposed structure of the alginate gel, in which calcium ions are fixed between the associated segments of the polymer chains, often called the "model boxes for eggs."

Research circular dichroism showed that calcium ions react preferably with segments prigorodovoy acid. It is possible that alternating segments polymannuronic acid does not play a direct role in gelation with calcium, except that connect the associated segments and, on this basis, ensure the formation of three-dimensional spatial grid circuits inside the gel.

The nature of the interaction between oligourethane segments and calcium ions was further clarified using the known geometry of the coordination model compounds, and the requirements of the cooperative Association. In this interaction polyglutamate segments are associated in aggregates with internodes, for which suitable calcium ions, model boxes on the stick of alginates from different sources. For example, alginate from Laminaria hyperborea with a high percentage polychlorinated segments forms a hard, brittle gels, which have a tendency to syneresis or loss of bound water. In contrast, alginate from Macrocystis pyrifera or Ascophyllum nodosum forms an elastic gel, which can be deformed and which have a markedly reduced tendency to syneresis.

Suitable alginates for use with this invention include, but are not limited to, alginates, sodium, alginates, potassium and ammonium alginates. Various alginates are commercially available from Kelco, a Division of Merck and Co., Inc. (San Diego, Canada). These alginates are changed in accordance with the algal source content mannurone acid and guluronic acid, molecular weight, particle shape and size of the sieve mesh. Alginates, commercially available from Kelco, include KELTONE HV, MANUGEL DMB, KELGIN MV and KELGIN f

Polyvalent cations will react with alginic polymers and in some cases to make these polymers. As content increases polyvalent ion in solution, will be salustiana, gelation and finally precipitation. Like other properties of alginic solutions, attitude mannurone and gully himself polyvalent ion will change the properties entered in the reaction of the alginate.

Polyvalent cation, most used to modify the rheology, viscosity and characteristics of the gel alginic solutions, is calcium. Calcium can also be used as precipitating ion for the formation of insoluble fibers and films.

Reaction with calcium, you can do a visual introduction injection flow 1% solution of sodium alginate (optional alginate or potassium alginate ammonium) in 10% solution of calcium chloride. Almost immediately alginate calcium will be formed on the surface of the stream of sodium alginate and the stream will keep the form he had when he was injected with the calcium chloride. Initially, the Central part will be unreacted sodium alginate, but after a certain period of time soluble calcium to diffuse into the center and forms a complete structure of calcium alginate.

The reaction between calcium ions and alginic molecules is represented as follows:

2NaAlg + Ca++= CaAlg2+ 2Na

When calcium ions are added to this system, the reaction proceeds right up until all of the alginate will not precipitate as calcium alginate.

The physical characteristics of the system alginates, sodium (or potassium, or as the tee with a weaker yield. Further addition of calcium ions leads to the formation of the gel, and finally settling.

Different algal sources give alginates with different block structure mannurone acid and guluronic acid. Each alginate has its own characteristic properties of calcium reactivity and gelation. Alginates are usually called "high M" or "high G", depending on the ratios mannurone acid and guluronic acid they contain.

As shown in table 1, Laminaria hyperborea gives alginate with a high G. In the usual terms of alginates with high G form a hard, brittle gels, which are heat resistant, whereas alginates with high M give the weaker, more elastic gels, which are less resistant, but more stable during repeated freeze. The final strength of the gel, however, can be adjusted by accessing the chemistry of the gels and in the case of some products alginates with high G and high M interchangeable.

Stoichiometric for complete replacement is required to 7.2% calcium, considering the weight of sodium alginate. Gels are formed with approximately 30% of this quantity and thickened, fluid rastvorilsya share of influence on the properties of the final gel. Too rapid addition of calcium leads to the spotted geleobrazovaniju, inhomogeneous structure of the gel or precipitation.

To regulate the speed of gelation can be a combination of alginate and slowly dissolve the calcium salt. Airing, such as the pyrophosphate tetranitride and sodium hexametaphosphate, also regulate the secretion of calcium ions and change the texture of the final gel.

For gel formation in cold water, you can use sodium alginate, anhydrous secondary acidic calcium phosphate, sodium citrate and adipic acid. When added to water, sodium citrate dissolves quickly and associates (sequestered) free calcium in the water, thereby allowing to dissolve the sodium alginate. Adipic acid dissolves slowly and reacts with anhydrous secondary acidic calcium phosphate, releasing calcium ions, which form a gel with sodium alginate. Citrate dihydrate may be replaced by such airing, such as the pyrophosphate tetranitride or other polyphosphates. Other calcium sources (calcium carbonate or calcium sulphate) can replace anhydrous secondary acidic calcium phosphate. Effective either slowly soluble food acid, than some other acids used in food products. Regulation of pH is necessary to prevent premature gelation or precipitation. When pH decreases, the ionization of the carboxyl groups is suppressed by loss of solubility; the first is gelation, followed by deposition, if the pH is reduced far enough. At a pH of about 3.5 alginate gel is a mixture of calcium and acid gel.

Widespread food and industrial uses of alginates is usually based on their ability to react with calcium ions to function advantageously as thickeners, film-forming means and gelling and texturing tools. As in the case of Gellan gum, because calcium ions are able to form gels, these ions, if present in high enough quantities, can inhibit the hydration of the alginate. Therefore, the acceptable practice is the use of alginates in combination with airing to promote hydration in cases in which the need to "soften" the water that was hydration.

In contrast, Gellan gum, alginates do not form gels with n is creative), they do not form a gel diffusion, but rather is dispersed in the aqueous medium with stirring. Sea water contains high levels of sodium ions and therefore should not be expected that the addition of solutions of alginates in seawater will lead to gel formation.

Us unexpectedly been found that solutions of alginates is actually really form a diffusion-nestrukturirovannye gels when added to water with high concentrations of sodium ions, for example sea water. Accordingly alginates can be used as an alternative to solutions of Gellan gum in the previously mentioned applications. Without binding theory it is believed that the ionic composition of sea water such that there is enough present multivalent ions, including calcium, to induce gel formation and to keep the alginate gel in the state, despite the presence of sodium ions and other, not forming gels ions, which can, depending on the relative content of multivalent (gelling) and agileoresund (generatorexe) ions to cause disintegration of the gel.

As already mentioned, the use of the invention in practical terms can often trabold in cold water. In addition, the strength required of the gel, which depends mainly on the concentration of the polymer may vary. It is therefore understandable considering cases that require the use of relatively low levels of alginate in combination with relatively high levels of sequestrant. In these cases, prescribe at the time of starting the diffusion ion in the solution will be preferable to link the gel-forming divalent ions, which leads to the possibility of dispersion of alginate in the surrounding aquatic environment before the gelation. In the case of Gellan gum, regardless of the relative concentrations of the gum and sequestrant cannot be controlled dispersion of the polymer prior to gelation, since gelation and recovery of the polymer will occur simultaneously through interaction with ions of sodium and other monovalent ions that are not bound by sequestrants.

Therefore, especially preferred embodiment of the invention is the use of solutions containing as alginate and Gellan gum. This combination not only eliminates loss of alginate by diffusion, but also provides an alternative texture of the gel and in some sluices irreversible and consist of vysokomineralizovannyh alginate polymers. By correct choice of gel-forming means you can regulate the structure and hardness of the gel. Soft gels tend to flow and take the shape of their container. Loss of water in the atmosphere, causing shrinkage of gels, alginic gels is very slow.

Alginate gels of the present invention and alginate gels of the invention comprising Gellan gum, suitable for a wide range of oil fields and other applications, including control profile (close to water), where the gel is used for keeping the flow of unwanted water or, preferably, the permeability reduction to water flow, at the same time not significantly affecting the flow of oil. Lost circulating gels must adjust the main quantity of fluids that are lost to the formation during applications for drilling or maintenance work on wells.

The use of "traffic jams" of the gel makes use of in cement spacers used between the liquids, or for cleaning pipelines, where the "pigs" of the gel to remove the remains of the rocks in the pipes. The gel structure is favorable to reduce convection when used in applications with an insulating packer-liquids, on the it environment. One of the uses is curing waste wells that take place in the operations of drilling and/or production. It may include curing natural occurring radioactive material and drill cuttings while drilling in the open sea. Another use is the manufacture of the lining of wells, which stops or reduces the leaching of chemicals into the soil below the wells, particularly in ground water.

Alginate gels, optionally comprising Gellan gum, useful as a means against fluid loss (in the form of films), ballast liquids for vehicles, means for reducing friction, which reduces the pressure drop or increase the flow rate, hydromulching coatings for lease of land (especially the slope), auxiliary means for stabilizing sand (water wells, piles for construction and so on), foam stabilizers with xanthan gum and as a barrier to water loss of the cement.

Example 1

Alginates restored in sea water

A solution of 1% KELTONE HV, sodium alginate highest grade received careful dispersing 3 g powder in 300 g deionized water using intensive pennou sea water, which was obtained in accordance with method D-1141-52 ASTM (American standard test method) dissolution 32,26 g sea salt (sea salt is available commercially from Lake Products Company, Inc. (Maryland Heights. MO) in 1 l deionized water. Watched the instant formation of a "gel-like worms. This example shows the ability of solutions of alginates obtained without heating, to form gels diffusion of ions when added to sea water.

Example 2

Gellan gum restored in sea water

0.5% solution of Gellan gum KELCOGEL was obtained by dissolving a mixture of 1.5 g of Gellan gum and 45% sodium citrate in 300 ml of deionized water using intensive mixing. Approximately 50 g aliquot of the solution was poured in a thin trickle in artificially reconstituted sea water, which was obtained by dissolving 32,26 g of sea salt in 1 liter of deionized water. Watched instant education "jelly worms.

This example shows the ability of solutions of Gellan gum obtained without heating, to form a gel by diffusion of ions when added to sea water.

Example 3

Alginates restored in sea water

As opisivao varieties with a high content of monomer guluronic acid). KELGIN MV and KELGIN F (medium viscosity, purified alginates, sodium). Each solution was poured into a restored sea water as described in example 1. The formation of gels occurred in all cases. Apparently the gel MANUGEL DMB slightly stronger than the other gels.

Example 4

Alginates in real sea water

As described in example 1 were obtained with 1% solutions of the following alginates: KELTONE HV, MANUGEL DMB (gelling alginate highest grade with a high content of monomer guluronic acid), KELGIN MV and KELGIN F (medium viscosity, purified alginates, sodium). Each solution was poured in accordance with the method of example 1 in the present marine water samples which were taken from the sea at the sea shore in Canada. The formation of gels occurred in all cases. Apparently the gel MANUGEL DMB slightly stronger than the other gels. This example and example 3 show that the gel formation is not limited to a particular alginates.

Example 5

Alginates in 1% solution of calcium chloride

As described in example 1 were obtained with 1% solutions of the following alginates: KELTONE HV, MANUGEL DMB (gelling alginate highest grade with a high content of monomer guluronic acid), KELGIN MV and KELGIN F (medium viscosity, peeled altania gels, stronger than the gels obtained in seawater occurred in all cases. Apparently the gel MANUGEL DMB slightly stronger than the other gels.

Example 6

Alginates in 1% solution of sodium chloride

As described in example 1 were obtained with 1% solutions of the following alginates: KELTONE HV, MANUGEL DMB (gelling alginate highest quality with a high content of monomer guluronic acid). KELGIN MV and KELGIN F (medium viscosity, purified alginates, sodium). Each solution was poured in accordance with the method of example 1 in a 1% solution of sodium chloride. Gels are not formed and the solutions were dispersibility in the aquatic environment with weak stirring.

This example shows that the formation of the gel in a solution of sodium salt does not occur.

Example 7

Alginates restored in sea water

Tap water in San Diego has a value of stiffness is typically about 180 M. D., expressed as calcium carbonate. Full hydration of alginates and Gellan gum in cold water faucet San Diego as a result of this required the use of sequestrant.

1% solution KELGIN MV was obtained in tap water for San Diego dispersion product using vigorous mixing and 0.10% added to kkuu water. The gel identified on the screens after about 16 hours, and found that it is soft and has the form of a jelly.

Formed above the liquid, a gel from which removed, were analyzed using the test phenol/sulphuric acid-soluble carbohydrate. No significant amount of carbon was not detected, this indicates that the polymer is essentially remained completely in the spatial grid of the gel and did not videochelsea in the surrounding liquid.

The experiment showed that the gelation still has a place when to implement the hydration you need a prescribe, and diffusion structuring method, described earlier, is extremely effective (essentially used all polymers).

Example 8

Gellan gum restored in sea water

0.5% solution of Gellan gum KELCOGEL got in the water crane San Diego dispersion product using vigorous mixing and 0.12% added sodium hexametaphosphate as sequestrant. The solution formed a gel when added to the recovered sea water. The gel was hard and brittle.

Formed above the liquid, a gel from which removed, were analyzed using the test procative, the polymer was essentially intact in the spatial grid of the gel and did not videochelsea in the surrounding liquid.

The experiment showed that the gelation still has a place when to implement the hydration you need a prescribe, and diffusion curing in the manner described previously, extremely efficient (essentially used all polymers).

Example 9

Alginates in combination with Gellan gum restored in sea water

A solution containing 0.3% KELCOGEL, 1% KELGIN MV and 0.12% sodium hexametaphosphate, got in the water crane San Diego dispersion product using vigorous stirring. The solution formed a gel when added to the recovered sea water. The gel was completely solid and coherent and differed in texture from the other two gels.

Formed above the liquid, a gel from which removed, were analyzed using the test phenol/sulphuric acid-soluble carbohydrate. No significant amount of carbon was not detected, this indicates that the polymer is essentially remained completely in the spatial grid of the gel and did not videochelsea in the surrounding liquid.

The experiment showed that guinate and Gellan gum forms strong gels and diffusion structuring method as described earlier, it is extremely effective (essentially used all polymers).

Example 10

Analysis of seawater

The sample recovered seawater used in examples 1, 2, 3, 7, 8 and 9, and a sample of real sea water used in example 4 were analyzed on the ionic composition of atomic absorption. The results were as follows:

Restored

Ca - 237,7 M. D.

K - 452,9 M. D.

Mg - 828,6 M. D.

Na - 960,1 M. D.

Restored

Ca - to 298.9 M. D.

K - 439,8 M. D.

Mg - 856,4 M. D.

Na - 9523.2 M. D.

The solution containing calcium, potassium, magnesium and sodium in the approximate proportions present in the restored sea water (and therefore also in the real sea water, because its composition is similar to the composition of the recovered sea water), were obtained by adding appropriate amounts of chlorides of each of these cations in deionized water. One percent solutions of sodium alginates KELTONE HV and KELGIN MV obtained in deionized water, as described, was added in the form of thin streams in the salt solution and again formed a "gel-like worms.

This example shows that the ionic composition of sea water case is I, there is enough calcium, so that the gelation of alginate.

1. The gel containing water, sodium ions, calcium ions and alginate, wherein the gel further comprises Gellan gum and prescribe and in which the ratio of sodium ions to calcium ions is between about 15 : 1 and about 45 : 1, the amount of alginate is between about 0.3 and 4 wt.%, the amount of Gellan gum is between about 0.05 and 4 wt.% and the number of sequestrant is between about 0.01 and 1.5 wt.%.

2. Gel under item 1, wherein the amount of alginate is between about 0.7 and 2 wt.%, the amount of Gellan gum is between about 0.2 and 1 wt.% and the number of sequestrant is between approximately 0.05% and 0.6 wt.%.

3. Gel under item 1, characterized in that the alginate contains mannurone acid and guluronate acid in a mass ratio between about 2 : 1 and 0.35 : 1.

4. The gel containing water, sodium ions, calcium ions and Gellan gum, wherein the gel further comprises prescribe, and the balance of sodium ions to calcium ions is between about 15 : 1 and about 45 : 1, number of Gellan gum is m is

 

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