Composition with efficient liquid-absorption capacity for various uses and method for producing same

Abstract

The present invention relates to a composition with absorption capacity characterised in that it comprises 5% to 50% sodium carboxymethyl cellulose; 0.01% to 5% D-sorbitol; 0.05% to 5% citric acid and 50% to 95% water. The invention also relates to a method for producing a composition with efficient liquid-absorption capacity for various uses characterised in that it comprises: a) mixing 0.05% to 5% w / w citric acid and 0.01% to 5% w / w D-sorbitol; b) partially prepolymerising the mixture of point (a) at a temperature between 80°C and 180°C for 30 minutes to 12 hours until a branched cross-linking prepolymer that is completely soluble in water is formed; c) completely dissolving the cross-linking prepolymer in water in a proportion of between 50% and 95% w / v; d) adding between 5% and 50% w / w sodium carboxymethyl cellulose until it solubilises and forms a gel with a moisture content of between 30% and 95%; e) dividing and dehydrating the gel at a temperature between 40°C and 90°C for 1 to 24 hours until a solid product is formed with a moisture content below 10%; f) grinding and sieving the product to a size of 0.1 mm to 5 mm; and g) esterifying with heat at 80°C to 180°C for 15 minutes to 12 hours.

Description

[0001] COMPOSITION WITH EFFICIENT LIQUID ABSORPTION CAPACITY FOR VARIOUS APPLICATIONS AND THE PROCESS FOR OBTAINING IT

[0002] FIELD OF INVENTION

[0003] The present invention relates to compositions of materials that have the ability to absorb water, more specifically to a hydrogel composition with the ability to efficiently absorb liquids for various applications and to a process for obtaining the same.

[0004] BACKGROUND OF THE INVENTION

[0005] Superabsorbent polymers, known for their ability to absorb and retain large quantities of water or aqueous fluids, are used in a variety of applications due to their capacity to form a stable gel once they have absorbed liquids. Their most prominent use is in personal hygiene products, such as disposable diapers and feminine hygiene products, where efficient absorption is crucial for comfort and leak prevention. In addition, these polymers play an important role in agriculture, where they are used as soil amendments to improve water retention, helping crops survive drought conditions by releasing water in a controlled manner to the plant roots.

[0006] At an industrial level, water-absorbent polymers are also used in medical applications, such as wound dressings, which help maintain a moist environment conducive to healing while absorbing exudate fluids.

[0007] In civil engineering, they can be incorporated into the formulation of construction materials to control humidity or prevent water accumulation in certain environments. Their chemical structure, generally based on cross-linked polymers such as sodium polyacrylate, is key to their ability to absorb multiple times their own weight in water, transforming into a gel that retains the liquid under pressure.

[0008] Existing products that perform similar functions include superabsorbents based on synthetic polymers, such as sodium polyacrylate, which are widely used in various commercial applications. These materials have the ability to absorb liquids while maintaining their structure.

[0009] They are commonly used in personal hygiene products, such as diapers and feminine hygiene products, as well as in industrial applications, such as food absorbents and in agriculture to improve water retention in the soil.

[0010] In addition to synthetic superabsorbents, there are also biodegradable and bio-based superabsorbents made from polysaccharides, proteins, or other polymers sourced sustainably. These materials are designed to offer absorbency levels that are typically lower than those of their synthetic counterparts, but with the advantage of being biodegradable, making them more attractive from both an environmental and health perspective.

[0011] One of the main drawbacks of synthetic super absorbents is that they are not biodegradable, meaning they persist in the environment for extended periods after use.

[0012] Their production and final disposal can have a negative impact on the environment due to their non-biodegradable nature and the potential release of chemicals and microplastics during their decomposition.

[0013] Synthetic superabsorbent polymers, such as polyacrylates, are synthesized using raw materials from fossil sources, making them unattractive in environmental terms.

[0014] Synthetic superabsorbents can contain a specific amount of unpolymerized residual monomer, which cannot be removed by washing. This can become a potentially hazardous source of contamination, particularly in applications involving direct contact with people or food. Although biodegradable, superabsorbents based on polysaccharides, proteins, or natural polymers do not offer the same level of performance in terms of absorbency, stiffness, and structure as their synthetic counterparts.

[0015] Some biodegradable superabsorbents may have trouble maintaining their structure after absorbing liquids, which can affect their effectiveness in various applications.

[0016] These biodegradable materials tend to be more expensive to produce compared to synthetic ones, and their availability may be limited in certain markets.

[0017] A search was conducted to determine the closest prior art, and the following documents were found.

[0018] US patent application 2 O 22 O 347655 A 1, dated October 2, 2020, was located, disclosing a method for preparing a water-absorbent crosslinked polyacrylic polymer comprising crosslinking the polyacrylic polymer with a crosslinking agent comprising a polyepoxide and a polyhydrazide. The crosslinking agent comprises approximately 0.1% to 10% by weight of polyepoxide and / or approximately 0.1% to 10% by weight of polyhydrazide based on the weight of the polyacrylic polymer.The polyacrylic polymer comprises a member selected from homopolymers and copolymers of ethylenically unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, 2-ethacrylic acid, 2-propylacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid and the like, as well as salts and anhydrides thereof; carboxymethyl cellulose and its salts; polyaspartic acids and its salts; polyglutamic acids and its salts; and carboxyethyl dextran and its salts. In certain embodiments, the polyacrylic acid polymer can be selected from the group consisting of α-poly(glutamic acid), γ-poly(glutamic acid), α-poI1i(aspartic acid), α-poI1i(aspartic acid), carboxymethyl cellulose, polyacrylic acid, polymethacrylic acid, poly(2-carboxyethyl acrylate), poly(2-ethylacrylate acid), poly(2-propylacrylate acid), poly(maleic acid), their copolymers and combinations thereof.

[0019] The polyepoxide may be a selected member of the group consisting of ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,3-butanediol diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentylglycol diglycidyl ether, resorcinol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, poly(I) ie ti (I) eng (I) ico (I) diglycidyl ethers, poly(I) propane diglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolethane triglycidyl ether, triethanolpropane diglycidyl ether, triethanolethane triglycidyl ether, glycerol propoxy lato triglycidyl ether, pentaerythritol tetra g I icidi I ether, castor oil no polyglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, and combinations thereof.

[0020] However, acrylic polymers have a wide range of homopolymers and copolymers of ethylenically unsaturated carboxylic acids, not all of which have the same effects and functions. While sorbitol and sorbitol poly(I) icidic ether are related chemical compounds, their structures and properties differ. Sorbitol poly(I) icidic ether is a derivative of sorbitol in which the hydroxyl groups have been modified to include epoxides. These epoxides are reactive groups that can form cross-links with other compounds. The overall structure includes several epoxy groups attached to the sorbitol backbone.

[0021] The aforementioned document also reveals that polyhydrazide may be a selected member of the group consisting of oxalyl dihydrazide, succinic acid dihydrazide, malonic acid dihydrazide, ethylmalonic acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, dodecanedioic acid dihydrazide, sebacic acid dihydrazide, italic acid dihydrazide, terephthalic acid dihydrazide, isophthalic acid dihydrazide, carbohydrazide, thiocarbohydrazide, citric acid trihydrazide, ethylenediaminetetraacetic acid tetrahydrazide, and combinations thereof.

[0022] Citric acid trihydrazide is a derivative of citric acid in which the carboxyl groups have been converted into hydrazide groups.

[0023] Therefore, the components of the formulation of the referred document may comprise very diverse components and it is not specified that one of the compositions is exactly that of our invention, nor is a possible formulation in the same percentages disclosed or suggested in its examples.

[0024] Also located was document W02009022358A1 by Ambrosio Luigi et al., dated August 10, 2007, which discloses a method for preparing a superabsorbent polymeric hydrogel. This method comprises crosslinking a precursor containing a carboxymethylcellulose salt (IceIuIose), optionally in combination with hydroxyethylcellulose salt (IceIuIose), using citric acid as a crosslinking agent and in the presence of a molecular spacer. The gel is then washed in a polar organic solvent and finally dried by phase inversion in a non-solvent for cellulose. Furthermore, the invention relates to the superabsorbent hydrogel obtainable by the method of the invention and its use in a number of different applications.

[0025] The invention also discloses a method for preparing a superabsorbent polymeric hydrogel, comprising the following steps:

[0026] (i) Crosslinking an aqueous solution of a precursor comprising at least one carboxymethylcellulose salt, in combination with another different cellulose-derived polymer, with citric acid as a crosslinking agent in the presence of a molecular spacer.

[0027] (i) Wash the gel obtained by swelling in a polar organic solvent at least once.

[0028] (iii) Dry the gel by phase inversion in a non-solvent for cellulose.

[0029] The other polymer derived from cellulose is hydroxyethyl acetate, where the molecular spacer is sorbitol. The polar organic solvent is selected from methanol and water.

[0030] But in this case the aqueous crosslinking comprises a carboxymethylcellulose salt combined with another different cellulose-derived polymer and requires a polar organic solvent, such as methanol, for washing the gel.

[0031] The referenced document does not reveal or suggest exactly the same components and percentages of a composition with efficient liquid absorption capacity for diverse applications such as that of the present invention, nor can our invention be deduced or inferred based on the information disclosed in the referenced documents.

[0032] Given the need for a composition with efficient liquid absorption capacity for various applications and a process for obtaining it that solves the aforementioned problems and offers a more effective and efficient product, the present invention was developed.

[0033] OBJECTIVES OF THE INVENTION

[0034] The main objective of the present invention is to make available a composition with efficient liquid absorption capacity for diverse applications, made of a fully bio-based super-absorbent material, which allows for the efficient absorption of liquids, while maintaining a stable and biodegradable structure.

[0035] Another objective of the invention is to make available a composition with efficient liquid absorption capacity for diverse applications, which can be used, but is not limited to, disposable personal hygiene products such as baby diapers, adult diapers and sanitary napkins; to block water penetration in underground power or communications cables, in self-healing concrete; horticultural water retention agents, spill control and aqueous waste fluids; in absorbent pads for meat, fruit and other foods.

[0036] Another objective of the invention is to make available a composition with efficient liquid absorption capacity for diverse applications, which, in addition to being fully bio-based, meets the requirements in terms of absorption and mechanical properties necessary to be incorporated as a direct substitute for synthetic polymers, without the need to modify existing production lines or processes.

[0037] Another objective of the invention is to make available a composition with efficient liquid absorption capacity for diverse applications, where the raw materials used are globally available, are economical, and where the process can be easily replicated and scaled up.

[0038] And all those qualities and objectives that will become apparent when making a general and detailed description of the present invention supported by the illustrated modalities.

[0039] BRIEF DESCRIPTION OF THE INVENTION

[0040] In general, the composition with efficient liquid absorption capacity for diverse applications, which allows obtaining a super-absorbent bio-based hydrogel, in accordance with the present invention, comprises:

[0041] a) Biodegradable base materials: Polysaccharides and / or natural proteins derived from renewable and sustainable sources, used as the base matrix of the absorbent material.

[0042] b) Crosslinking agents: Especially carboxylic acids, these are used to crosslink polymers and improve absorption capacity. c) Branching agents: Used to expand the molecular chain of the polymerization that takes place between the base matrix and the crosslinking agent.

[0043] d) Water

[0044] These natural polysaccharides and / or proteins, derived from renewable and sustainable sources and used as the base matrix of the absorbent material, are selected from the group consisting of nanocellulose, hydroxyethylcellulose, hydroxypropyl methylcellulose, hydroxyalkylcellulose, hydroxypropyl methylcellulose, carboxyalkylcellulose, sodium carboxymethylcellulose, and carboxyethylcellulose. Preferably, sodium carboxymethylcellulose (CMC), nanocellulose, hydroxyethylcellulose, or a combination thereof may be used.

[0045] Sodium carboxymethylcellulose can have a degree of substitution of between 0.5 and 2.0. The properties of sodium carboxymethylcellulose will depend on the degree of substitution.

[0046] The polysaccharides must have a viscosity of 1% by weight (w / w) of an aqueous solution at room temperature (25°C), or greater than 200 centipoise (cps), within a range of 200 cps to 12,000 cps.

[0047] The molecular weight of polysaccharides can have a polydispersity index of less than 10 within a range of approximately 1 to 10. Such carboxylic acids, as crosslinking agents, are selected from the group consisting of malic acid, succinic acid, acetic acid, citric acid, butanedioic acid, formic acid, monosuccinic acid tartrate, itaconic acid, citraconic acid, oxalic acid, tartaric acid, oxydisuccinic acid, thiodisuccinic acid, benzoic acid, transaconitic acid, melitic acid, disuccinic acid, benzenehexacarboxylic acid, or mixtures thereof.

[0048] These branching agents, used to expand the molecular chain of the polymerization that takes place between the base matrix and the crosslinking agent, are selected from the group consisting of organic compounds of polyalcohols or sugar alcohols, such as glycerin, diglycerin, propylene glycol, D-sorbitol, xylitol, lactylol, D-mannitol, maltitol, arabitol, 1-5 pentanediol and 1-6 hexanediol.

[0049] Quantitatively, the composition with efficient liquid absorption capacity for diverse applications, according to the present invention, comprises:

[0050] From 5% to 50% w / w of sodium carboxymethyl cellulose;

[0051] From 0.01% to 5% w / w D-sorbitol;

[0052] From 0.05% to 5% w / w of citric acid;

[0053] 50% to 95% v / w water.

[0054] In its preferred form, where the composition offers the best performance, it quantitatively comprises:

[0055] 40% w / w sodium carboxymethyl cellulose;

[0056] 0.04% w / w of D-sorbitol;

[0057] 0.2% w / w citric acid;

[0058] 59.76% v / w of water.

[0059] The process of obtaining a composition with efficient liquid absorption capacity for diverse applications comprises:

[0060] a) Mix crosslinking agents such as a carboxylic acid, preferably citric acid in a weight percentage of between 0.05% to 5% w / w, with branching agents such as a polyalcohol, preferably D-Sorbitol in a w / w percentage of between 0.01% to 5% w / w;

[0061] b) Partially prepolymerize the mixture from section (a) by means of heat at a temperature between 80°C and 180°C for a time between 30 minutes and 12 hours until a crosslinking branched prepolymer is formed that is completely soluble in water;

[0062] c) Dissolve the crosslinking prepolymer completely in water in a proportion of between 50% and 95%;

[0063] d) Add a natural polysaccharide, preferably sodium carboxymethyl cellulose, in a weight percentage of between 5% and 50% until completely solubilizes and forms a gel with a moisture percentage between 30-95%;

[0064] e) Section and dehydrate the gel by thermal methods at temperatures between 40°C and 90°C for a period of 1 to 24 hours, until a solid product is formed with a moisture percentage below 10%;

[0065] f) Grind and sieve the product to form a homogeneous granular product in the particle size range between 0.1 mm and 5 mm;

[0066] g) Esterify in a controlled manner by means of heat in a range of 80°C to 180°C for a period of 15 minutes to 12 hours, to create polymer networks stable against deformation and pressure with high absorption capacity.

[0067] To better understand the characteristics of the invention, the following illustrative but not limiting drawings are included as an integral part of this description.

[0068] BRIEF DESCRIPTION OF THE FIGURES

[0069] Figure 1 shows a Pareto chart of the standardized effects (response is FSC (Y1 ), a = 0.05) with the magnitude of the statistical significance of the factors in the studied response variable for the composition with efficient absorption capacity of liquids for diverse applications.

[0070] Figures 2a, 2b, 2c, and 2d show residual plots for free absorption capacity (FSC) with the output variables (Y1), with the FSC response (Y1) showing the normal probability plot, fits, histogram, and order, respectively, of residual tests performed to validate the study using the assumptions of normality, homoscedasticity, and independence.

[0071] For a better understanding of the invention, a detailed description of some of its modalities will be given, shown in the drawings that are attached to this description for illustrative but not limiting purposes.

[0072] DETAILED DESCRIPTION OF THE INVENTION

[0073] The characteristic details of the hydrogel composition with efficient liquid absorption capacity for various applications, in accordance with the present invention, are clearly shown in the following description and in the attached illustrative drawings, the same reference signs serving to indicate the same parts.

[0074] The optimization of the composition with efficient liquid absorption capacity for diverse applications and the process of obtaining it, which forms a bio-based super-absorbent hydrogel with excellent stability and biodegradability, was obtained using design of experiments (DOE) and analysis of variance (ANOVA) techniques, which allow identifying and quantifying the impact of various factors on the properties of the hydrogel.

[0075] Examples of composition:

[0076] a) Preparation of super absorbent hydrogel with citric acid prepolymer and D-sorbitol in a 5:1 ratio.

[0077] A prepolymer (PP) is prepared from a 5:1 ratio of citric acid and D-sorbitol, which is then heated in an oven at 150°C for 90 minutes. After this process, 0.8 g of the PP is weighed and added to 2,000 ml of water; this solution is mixed until homogeneous.

[0078] Next, 100 g of sodium carboxymethyl cellulose is added and mixed to form the hydrogel matrix. This material is then mixed to incorporate the matrix with the prepolymer. The resulting product is dried for 8 hours at 65°C. Once dry, the hydrogel is ground and sieved to obtain a particle size between 0.15 mm and 0.8 mm.

[0079] The material, in its granular form, undergoes a crosslinking process in a convection oven with a rotating drum arrangement at 140°C for 40 minutes. Free absorption (FSC) testing of this sample yielded an absorption of 22.37g.

[0080] b) Preparation of superabsorbent hydrogel with prepolymer defined by succinic acid and D-sorbitol in a 1:1 ratio. A prepolymer (PP) consisting of a 1:1 ratio of succinic acid and D-sorbitol is prepared and placed in an oven at a temperature of 150°C for 60 minutes. At the end of this process, 0.8 g of the PP is weighed and added to 1000 ml of water; this solution is mixed until homogenized.

[0081] Next, 100 g of sodium carboxymethyl cellulose is added and mixed to form the hydrogel matrix. This material is then mixed to incorporate the matrix with the prepolymer. The resulting product is dried for 8 hours at 65°C. Once dry, the hydrogel is ground and sieved to obtain a particle size between 0.15 mm and 0.8 mm.

[0082] The material, in its granular form, undergoes a crosslinking process, which is carried out in a convection oven with a rotating drum arrangement at a temperature of 140°C for 40 minutes. The absorption value obtained in this example was 18.70 g / g.

[0083] c) Preparation of super absorbent hydrogel with 1:1 malic acid prepolymer and sorbitol.

[0084] A prepolymer (PP) is prepared from a 1:1 ratio of succinic acid and D-sorbitol, which is then heated in an oven at 150°C for 60 minutes. After this process, 1.2 g of the PP is weighed and added to 1,000 ml of water, and the solution is mixed until homogeneous. Then, 150 g of sodium carboxymethyl cellulose is added and mixed to form the hydrogel matrix. This material is then mixed to incorporate the matrix with the prepolymer. The resulting product is dried for 8 hours at 65°C. Once dry, the hydrogel is ground and sieved to obtain a particle size between 0.15 mm and 0.8 mm.

[0085] The granular material is then crosslinked in a convection oven with a rotating drum arrangement at 140°C for 40 minutes. A FSC of 15.03 g / g was obtained.

[0086] d) Preparation of super absorbent hydrogel with 5:1 citric acid prepolymer and D-sorbitol with added gelatin.

[0087] A prepolymer (PP) is prepared consisting of a 5:1 ratio of citric acid and D-sorbitol, which is placed in an oven at a temperature of 150°C for 90 minutes. At the end of this process, 1.44 g of the PP is weighed out, along with 3.6 g of gelatin and 900 ml of water. This solution is heated to a temperature of 50°C and mixed until homogenized.

[0088] Next, 180 g of sodium carboxymethyl cellulose is added and mixed to form the hydrogel matrix. This material is then mixed to incorporate the matrix with the prepolymer. The resulting product is dried for 8 hours at 65°C. Once dry, the hydrogel is ground and sieved to obtain a particle size between 0.15 mm and 0.8 mm.

[0089] The granular material is then crosslinked in a convection oven with a rotating drum arrangement at a temperature of 140°C for 40 minutes, resulting in an absorption of 23.12 g / g.

[0090] The composition that obtained the best free absorption results is example d), with 23.12 g / g. This composition contains gelatin as an additive, helping to improve the absorption capabilities of the hydrogel.

[0091] Below are some examples of formulations of the composition with efficient liquid absorption capacity for various applications.

[0092] Examples of formulation:

[0093] a) Preparation of super absorbent hydrogel with 5:1 citric acid prepolymer and sorbitol.

[0094] A prepolymer (PP) is prepared from a 5:1 ratio of citric acid and sorbitol, which is then heated in an oven at 150°C for 90 minutes. After this process, 15.2 g of the PP are weighed and added to 2184.8 ml of water; this solution is mixed until homogeneous.

[0095] Next, 1800 g of carboxymethyl cellulose is added and mixed to form the hydrogel matrix. This material is then mixed to incorporate the matrix with the prepolymer. The resulting product is dried for 8 hours at 65°C. Once dry, the hydrogel is ground and sieved to obtain a particle size between 0.15 mm and 0.8 mm.

[0096] The granular material is then crosslinked in a convection oven with a rotating drum arrangement at 140°C for 40 minutes. The resulting FSC content was 22.73 g / g.

[0097] b) Preparation of super absorbent hydrogel with 1:3 citric acid prepolymer and sorbitol.

[0098] A prepolymer (PP) is prepared from a 1:3 ratio of citric acid and sorbitol, which is then heated in an oven at 110°C for 60 minutes. After this process, 2.45 g of the PP are weighed and added to 422.55 ml of water; this solution is mixed until homogeneous.

[0099] Next, 75 g of carboxymethyl cellulose is added and mixed to form the hydrogel matrix. This material is then mixed to incorporate the matrix with the prepolymer. The resulting product is dried for 8 hours at 65°C. Once dry, the hydrogel is ground and sieved to obtain a particle size between 0.15 mm and 0.8 mm.

[0100] The material, in its granular form, undergoes a crosslinking process in a convection oven with a rotating drum arrangement at 100°C for 180 minutes, resulting in an absorption of 22.15 g / g in FSC.

[0101] c) Preparation of super absorbent hydrogel with 5:1 citric acid prepolymer and sorbitol with added gelatin.

[0102] A prepolymer (PP) is prepared from a 5:1 ratio of citric acid and sorbitol, which is then placed in an oven at 150°C for 90 minutes. After this process, 2.11 g of the PP are weighed out, and 10 g of gelatin and 2997.89 ml of water are added. This solution is heated to 50°C and mixed until homogenized.

[0103] Then, 1000 g of carboxymethyl cellulose is added and mixed until the hydrogel matrix is ​​formed. This material is then mixed to incorporate the matrix with the prepolymer. The resulting product is dried for 8 hours at 65°C. Once dry, the hydrogel is ground and sieved to obtain a particle size between 0.15 mm and 0.8 mm.

[0104] With the material in its granular form, it undergoes a crosslinking process, which is carried out in a convection oven with a rotating drum arrangement at a temperature of 140°C for 40 minutes. An absorption of 25.85 g / g was obtained with the addition of gelatin to formula a). d) Preparation of superabsorbent hydrogel with 2.6:1 citric acid prepolymer and D-sorbitol.

[0105] A prepolymer (PP) is prepared consisting of a 2.6:1 ratio of citric acid and sorbitol, which is placed in an oven at a temperature of 130°C for 120 minutes. At the end of this process, 20.9 g of the PP are weighed and added to 2179.10 ml of water; this solution is mixed until homogenized.

[0106] Next, 1800 g of carboxymethyl cellulose is added and mixed to form the hydrogel matrix. This material is then mixed to incorporate the matrix with the prepolymer. The resulting product is dried for 8 hours at 65°C. Once dry, the hydrogel is ground and sieved to obtain a particle size between 0.15 mm and 0.8 mm.

[0107] The material, in its granular form, undergoes a crosslinking process in a convection oven with a rotating drum arrangement at a temperature of 140°C for 180 minutes. A free absorption of 22.44 g / g was obtained.

[0108] The variation of formulations carried out indicates that the prepolymer with the best results was the 5:1 citric acid with D-sorbitol, for example a) resulting in an absorption of 22.73 g / g, however, in example c) a considerable improvement was obtained due to the addition of gelatin, obtaining a 13% improvement in absorption compared to example a).

[0109] Thanks to the experimental techniques implemented, the formula used to produce a bio-based superabsorbent material was optimized. This allowed researchers to determine the most efficient combination of ingredients and which components are strictly necessary for manufacturing this superabsorbent formulation. Table 1 shows a comparison of hydrogel-free absorption with and without a prepolymer.

[0110] Table 1.

[0111]

[0112]

[0113] CMC: Sodium carboxymethyl cellulose

[0114] AC: Citric acid

[0115] S: D-Sorbitol

[0116] FSC: Free Absorption Capacity

[0117] PP: Preprolimer

[0118] Table 1 defines the name of each sample using two notations. The first, identified by the "+" sign, refers to samples where the components are added without the crosslinking process. The second notation, using the "" sign, refers to samples with the crosslinking process.

[0119]

[0120] The prepolymer percentage column refers to samples that do not have the crosslinking process.

[0121] Each composition has two samples, only one with the cross-linking process and the other without that cross-linking process. It can be observed how the introduction of the prepolymer (responsible for the cross-linking) improves the free absorption capacity (FSC) of the studied material.

[0122] These results indicate that incorporating the proposed methodology, in addition to the prepolymers used, improves absorption capabilities. This confirmed the initial functionality of the invention.

[0123] With this information, a sequence of studies was developed to understand the significance of each component and, thereby, optimize the process to obtain a formula with a higher performance in the absorption capacity of the material.

[0124] Within these studies, design of experiments (DOE) and analysis of variance (ANOVA) techniques were used, which allow the identification and quantification of the impact of seven factors on the properties of the hydrogel; a fractional factorial DOE 2< was used 7 - 4 ), composed of seven factors with resolution IV to perform the analysis, in addition, center points were used in order to detect statistical significance in the curvature.

[0125] The factors and levels are presented below in Table 2 in a coded manner; these factors were studied to optimize the response variable of free absorption capacity (FSC).

[0126] Table 2.

[0127]

[0128]

[0129] Table 3 below presents the summary of the statistical model, where the study found that 82.46% of the variation in free absorption capacity is explained by the presented model.

[0130] Table 3.

[0131]

[0132] S = Sample standard deviation

[0133] The ANOVA of this study is presented in Table 4. This analysis describes the statistical significance of each factor. The Pareto chart (See Figure 1) graphically describes the magnitude of the significance of the factors in the studied response variable.

[0134] page 4.

[0135]

[0136]

[0137] GL = Degrees of Freedom.

[0138] SC Ajust= Adjusted sum of squares

[0139] MC Ajust= Adjusted mean square

[0140] The factors that are statistically significant for the response variable are listed in order of magnitude:

[0141] 1. F

[0142] 2. A

[0143] 3. G

[0144] 4. AD 5. E

[0145] 6. AF

[0146] With this analysis completed, a series of residual tests are performed to validate the study, in which assumptions of normality, homoscedasticity and independence are verified. In this case, the three assumptions presented in the graphs of figures 2a, 2b, 2c and 2d are satisfactorily met, so it is possible for us to make statistical inferences accurately and precisely, in addition to giving us the ability to seek to optimize the synthesis of superabsorbent hydrogel.

[0147] As a result, the process was optimized, ensuring with 95% confidence that a synthesis with an absorption capacity yield between 19.2 g / g and 25.5 g / g will be obtained. This information is presented in Table 5.

[0148] Table 5.

[0149]

[0150] FSC:

[0151] Free Absorption Capacity (Y 1 )= Output Variable

[0152] SE = Standard Error of Adjustment

[0153] IC = Confidence Interval

[0154] IP = l Prediction Interval

[0155] Based on the above analysis, the following composition with efficient liquid absorption capacity for diverse applications was obtained, in accordance with the present invention: - Biodegradable base materials: Polysaccharides and / or natural proteins derived from renewable and sustainable sources, used as the base matrix of the absorbent material.

[0156] Crosslinking agents: Especially carboxylic acids, these are used to crosslink polymers and improve absorption capacity.

[0157] Branching agents: Used to expand the molecular chain of the polymerization that takes place between the base matrix and the crosslinking agent.

[0158] Said biodegradable base material is preferably sodium carboxymethyl cellulose.

[0159] The crosslinking agent used to crosslink the polymers and improve absorption capacity is preferably citric acid.

[0160] The branching agent used to expand the molecular chain of the polymerization that takes place between the base matrix and the crosslinking agent is preferably D-sorbitol. Consequently, the composition with efficient liquid absorption capacity for diverse applications according to the present invention comprises polysaccharides, specifically sodium carboxymethyl cellulose (CMC), as the structural matrix. This innovative formulation uses a combination of a carboxylic acid, such as citric acid, as a crosslinking agent, and a polyalcohol, such as D-sorbitol, to act as an expander and brancher of the molecular chain of this prepolymer. The synergy between these components allows for the generation of a hydrogel that can expand more efficiently and, consequently, absorb a greater volume of water.

[0161] Sodium carboxymethyl cellulose (CMC) is selected as a structural matrix due to its biocompatible and biodegradable properties. CMC is a cellulose derivative with a high capacity to form gels and retain water, making it ideal for superabsorbent hydrogel applications. The presence of carboxymethyl groups in the cellulose structure allows for easy chemical modification and enhances the hydrogel's water absorption capacity.

[0162] Citric acid is used as a crosslinking agent due to its ability to form covalent bonds with the sodium carboxymethyl cellulose (CMC) matrix. By reacting with the functional groups of sodium carboxymethyl cellulose (CMC), citric acid introduces crosslinking sites within the polymer matrix, providing a more stable and resilient three-dimensional structure. This crosslinking significantly improves the hydrogel's ability to retain water under mechanical stress.

[0163] D-sorbitol is incorporated into the formulation as a molecular chain expander and brancher. Its polyalcohol structure allows it to interact with the sodium carboxymethyl cellulose (CMC) matrix and citric acid, acting as a flexible bridge that separates and branches the cross-linked polymer chains. This additional separation between the chains allows for greater expansion of the hydrogel when it absorbs water, thus increasing its swelling capacity and absorption volume.

[0164] Quantitatively, the composition with efficient liquid absorption capacity for diverse applications, according to the present invention, comprises:

[0165] From 5% to 50% w / w of sodium carboxymethyl cellulose;

[0166] From 0.01% to 5% w / w D-sorbitol;

[0167] From 0.05% to 5% w / w of citric acid;

[0168] 50% to 95% v / w water.

[0169] In its preferred form, where the composition offers the best performance, it quantitatively comprises:

[0170] 40% w / w sodium carboxymethyl cellulose;

[0171] 0.04% w / w of D-sorbitol;

[0172] 0.2% w / w citric acid; 59.76% v / w water.

[0173] The synthesis process for the composition is based on the initial implementation of a prepolymer, which is essential to the process. By subjecting a polyalcohol to partial polymerization with a carboxylic acid through a heat treatment between 80°C and 180°C for a period of 30 minutes to 12 hours, a branched and crosslinking prepolymer, completely soluble in water, is obtained. When incorporated into the hydrogel, this prepolymer aids in the formation of its polymer network and also serves as a spacer for the polymer chains, resulting in greater swelling capacity and, consequently, greater absorption. The following stages consist of a set of methodologies, such as the mixing and incorporation of two phases: a solid phase and a liquid phase. This process is fundamental, as homogenizing the mixture ensures complete hydration of the polysaccharide.This allows the expansion of the polymer chains and gives rise to the formation of a three-dimensional network, which is essential for the hydrogel to absorb and retain water. Another important step in the process is drying through a heat treatment of 40° to 90° for periods of 15 minutes to 24 hours. Removing moisture from the hydrogel prevents the particles from clumping together and also allows for better handling during the crushing and sieving process. These processes are crucial for achieving uniform particle size between 100 and 2 mm, depending on the application, as this stage of the process can determine the material's absorption capacity and speed.

[0174] The synthesis process of the bio-based superabsorbent material is based on an improvement of current processes through the implementation of a prepolymer in the initial stage, which is indispensable in the process, since by subjecting a polyalcohol with a carboxylic acid to partial polymerization by means of a heat treatment between 80°C and 180°C for a period of 15 minutes to 12 hours to obtain a branched and crosslinking prepolymer that is completely soluble in water, which, when incorporated into the hydrogel, helps in the formation of its polymer network, in turn serving as a spacer of polymer chains, which translates into a greater swelling capacity, and therefore, absorption.This step improves the dimensional stability of the hydrogel, preventing it from deforming or swelling excessively until it breaks, thus improving the mechanical resistance of the material. Similarly, it affects the absorption capacity of the hydrogel; a higher level of cross-linking (higher temperatures or cross-linking times) reduces the swelling capacity, while a lower level of cross-linking increases the absorption capacity.

[0175] The process of obtaining a composition with efficient liquid absorption capacity for diverse applications comprises:

[0176] a) Mix crosslinking agents such as a carboxylic acid, preferably citric acid in a weight percentage of between 0.05% to 5% w / w, with branching agents such as a polyalcohol, preferably D-Sorbitol in a w / w percentage of between 0.01% to 5% w / w;

[0177] b) Partially prepolymerize the mixture from part (a) by means of heat at a temperature between 80°C and 180°C for a time between 30 minutes and 12 hours until a branched crosslinking prepolymer completely soluble in water is formed; this reaction is represented below, p

[0178]

[0179] Molecule (A) represents citric acid, which undergoes a dehydration reaction, losing one water molecule (H2O) to form a cyclic lactone (B). Then, the sorbitol molecule (C) is added to form a compound with the lactone (D). This compound loses another water molecule to form an ester with a cyclic structure (E). Similarly, compound (F) is created, which undergoes dehydration of two water molecules. These final molecules cause a polymerization reaction, resulting in elongation and branching of the prepolymer chain.

[0180] It is important to note that ester bonds are ideal for our application because these bonds can be easily hydrolyzed, resulting in better biodegradability.

[0181] c) Dissolve the crosslinking prepolymer completely in water in a proportion of between 50% and 95%;

[0182] d) Add a natural polysaccharide, preferably sodium carboxymethyl cellulose, in a weight percentage of between 5% and 50% until completely solubilized and forming a gel with a moisture percentage between 30-95%;

[0183] e) Section and dehydrate the gel by thermal methods at temperatures between 40°C and 90°C for a period of 1 to 24 hours, until a solid product is formed with a moisture percentage below 10%;

[0184] f) Grind and sieve the product to form a homogeneous granular product in the particle size range between 0.1 mm and 5 mm;

[0185] g) Esterify in a controlled manner by means of heat in a range of 80°C to 180°C for a period of 15 minutes to 12 hours, to create polymer networks stable against deformation and pressure with high absorption capacity.

[0186] The resulting structure is completely biodegradable, non-toxic, functional and bio-based, suitable for various industrial and commercial applications.

[0187] The invention has been described sufficiently so that a person with average knowledge in the subject can reproduce and obtain the results mentioned in the present invention.

[0188] However, any person skilled in the technical field to which the present invention pertains may be able to make modifications not described in the present application; however, if the application of these modifications to a given structure or to the manufacturing process thereof requires the material claimed in the following claims, such structures shall be included within the scope of the invention.

Claims

CLAIMS Having sufficiently described the invention, the following claims are claimed as property.

1. A composition with efficient liquid absorption capacity for diverse applications, characterized by comprising: a) Biodegradable base materials such as polysaccharides and / or natural proteins derived from renewable and sustainable sources, used as the base matrix of the absorbent material. b) Crosslinking agents, especially carboxylic acids, to crosslink the polymers and improve absorption capacity. c) Branching agents used to expand the molecular chain of the polymerization that takes place between the base matrix and the crosslinking agents. d) Water.

2. The composition with efficient liquid absorption capacity for various applications, according to claim 1, characterized in that said natural polysaccharides are selected from the group consisting of nanocellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxyalkylcellulose, hydroxypropylmethylcellulose, carboxyalkylcellulose, sodium carboxymethylcellulose and carboxyethylcellulose. 3.- The composition with efficient liquid absorption capacity for various applications, according to claim 1, characterized in that said natural polysaccharide is sodium carboxymethylcellulose.

4. The composition with efficient liquid absorption capacity for various applications, according to the preceding claims, characterized in that said natural polysaccharides have a viscosity in a range of 200 cps to 12,000 cps. 5.- The composition with efficient liquid absorption capacity for various applications, according to claim 3, characterized in that said sodium carboxymethylcellulose has a degree of substitution of between 0.5 and 2.

0.

6. The composition with efficient liquid absorption capacity for various applications, according to the preceding claims, characterized in that said natural polysaccharides have a polydispersity index in the range of approximately 1 to 10. 7.- The composition with efficient liquid absorption capacity for diverse applications, according to the claim 1, characterized in that said carboxylic acids as crosslinking agents are selected from the group consisting of malic acid, succinic acid, acetic acid, citric acid, butanedioic acid, formic acid, monosuccinic tartrate, itaconic acid, citraconic acid, oxalic acid, tartaric acid, oxydisuccinic acid, thiodisuccinic acid, benzoic acid, transaconitic acid, melitic acid, disuccinic acid, benzenehexacarboxylic acid or mixtures thereof. 8.- The composition with efficient liquid absorption capacity for various applications, according to claim 1, characterized in that said carboxylic acid is citric acid.

9. The composition with efficient liquid absorption capacity for various applications, according to claim 1, characterized in that said branching agents are selected from the group consisting of organic compounds of polyalcohols or sugar alcohols such as glycerin, diglycerin, propylene glycol, D-sorbitol, xylitol, lactylol, D-mannitol, maltitol, arabitol, 1-5 pentanediol and 1-6 hexanediol. 10.- The composition with efficient liquid absorption capacity for various applications, according to claim 1, characterized in that said branching agent is D-sorbitol. 1 1.- The composition with efficient liquid absorption capacity for various applications, according to any of the preceding claims, characterized in that it comprises: From 5% to 50% w / w of sodium carboxymethyl cellulose; From 0.01% to 5% w / w D-sorbitol From 0.05% to 5% w / w of citric acid 50% to 95% v / w water.

12. A process for obtaining a composition with efficient liquid absorption capacity for various applications, as claimed in claims 1 to 11, characterized by comprising: a) Mix 0.05% to 5% w / w citric acid as a crosslinking agent and 0.01% to 5% w / w D-sorbitol as a branching agent; b) Partially prepolymerize the mixture from section (a) by means of heat at a temperature between 80°C and 180°C for a time between 30 minutes and 12 hours until a crosslinking branched prepolymer is formed that is completely soluble in water; c) Dissolve the crosslinking prepolymer completely in water in a proportion of between 50% to 95% w / v; d) Add between 5% and 50% sodium carboxymethyl cellulose as the base matrix, until completely solubilized and a gel is formed with a moisture percentage between 30-95%; e) Section and dehydrate the gel using thermal methods at temperatures between 40°C and 90°C for a period of 1 to 24 hours, until a solid product is formed with a moisture percentage below 10%; f) Grind and sieve the product to form a homogeneous granular product in the particle size range between 0.1 mm and 5 mm; g) Esterify in a controlled manner by means of heat in a range of 80°C to 180°C for a period of 15 minutes to 12 hours, to create stable polymer networks with high absorption capacity.

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