Polymer

Abstract

The present specification discloses polymers. The polymer may be an absorbent polymer used to form a so-called SAP. Such a polymer can be formed without using a so-called cross-linking agent or by minimizing the amount of the cross-linking agent by adjusting the material applied to the cross-linking process for forming the SAP and the conditions of the cross-linking process, thereby exhibiting excellent absorption ability. The polymer can be formed by crosslinking a biodegradable material even without using or minimizing a crosslinking agent, thereby exhibiting maximum biodegradability of the material. The invention also discloses application of the polymer.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0183662, filed on December 23, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] This specification discloses polymers and their uses. Background Art

[0003] Hydrogel polymers or hydrogels are generally defined as crosslinked hydrophilic polymers.

[0004] Such polymers can be used as materials called SAP (Super Absorbent Polymer). SAP is a material that can absorb tens to thousands of times its own weight of water. SAP is used in various applications such as hygiene products like sanitary products or diapers, medical products, household materials, agricultural materials, horticultural materials, transportation materials, civil engineering and construction materials, materials related to electrical and electronic devices, or water treatment agents.

[0005] The most widely used hydrogel polymer as SAP is a polymer made of vinyl-based materials, such as crosslinked polyacrylic acid.

[0006] Such materials are relatively inexpensive and have excellent absorption capacity, but they cause various problems because they remain semi-permanently even after being discarded.

[0007] To solve such problems, various attempts have been made to manufacture SAP from so-called biodegradable materials.

[0008] However, the materials known so far cannot form SAPs with balanced physical properties. For example, the most representative physical property required for SAP is absorption capacity, but in the SAPs of biodegradable materials known so far, at least one of the properties of absorption capacity and biodegradability cannot be ensured satisfactorily, or in some cases, neither of the two physical properties can be ensured at an appropriate level.

[0009] For example, in order to use a biodegradable material as SAP, the biodegradable material must be crosslinked to an appropriate level. Since the materials usually used as crosslinking agents do not have biodegradability or have poor biodegradability, crosslinking must be carried out without using a crosslinking agent or minimizing its usage amount. However, biodegradable materials do not have crosslinking sites or have poor crosslinking sites, and even when they have some crosslinking sites, there is a problem that the degree of crosslinking decreases according to the structure. Summary of the Invention

[0010] Technical Problem

[0011] This specification discloses polymers. This specification aims to disclose the following: adjusting the materials applied in the crosslinking process for forming SAP and the conditions of the crosslinking process to provide polymers that effectively have excellent absorption capacity even without using the so-called crosslinking agent or minimizing its usage amount. In addition, this specification aims to disclose the following: forming SAP by crosslinking biodegradable materials even without using a crosslinking agent or minimizing it, thereby maximizing the biodegradability of the materials. This specification also discloses the uses of the polymers.

[0012] Technical solutions

[0013] Among the physical properties mentioned in this specification, when the measurement temperature affects the physical properties, unless otherwise specified, the relevant physical properties are the physical properties measured at room temperature.

[0014] In this specification, the term "room temperature" means the natural temperature without special heating or cooling, which can mean any temperature in the range of, for example, 10°C to 30°C, or a temperature around about 23°C, about 25°C, or about 27°C. Unless otherwise specified, the unit of temperature mentioned in this specification is degrees Celsius (°C).

[0015] Among the physical properties mentioned in this specification, when the measurement pressure affects the physical properties, unless otherwise specified, the relevant physical properties are the physical properties measured under normal pressure.

[0016] In this specification, the term "normal pressure" means the natural pressure without special pressurization or depressurization, which can mean a pressure around about 730 mmHg to 790 mmHg.

[0017] Among the physical properties mentioned in this specification, when the measurement humidity affects the physical properties, unless otherwise specified, the relevant physical properties are the physical properties measured at room temperature and normal pressure under humidity without special adjustment.

[0018] This specification discloses polymers.

[0019] The polymer can be a so-called crosslinked polymer or can be a polymer before crosslinking. If the polymer is a crosslinked polymer, the polymer can be a hydrogel polymer or a hydrogel.

[0020] The polymer can be an absorbent polymer.

[0021] Such an absorbent polymer can exhibit at least one of the water content, centrifuge retention capacity (CRC), and absorption under pressure (AUP) within the ranges described herein.

[0022] For example, the lower limit of the centrifuge retention capacity (CRC) of the polymer according to EDANA (European Disposables and Nonwovens Association) method WSP 241.3 can be about 10 g / g, 15 g / g, 20 g / g, 25 g / g, 30 g / g, 35 g / g, 40 g / g, or 45 g / g, and the upper limit thereof can be about 100 g / g, 95 g / g, 90 g / g, 85 g / g, 80 g / g, 75 g / g, 70 g / g, 65 g / g, 60 g / g, 55 g / g, 50 g / g, 45 g / g, 40 g / g, or 35 g / g. The centrifuge retention capacity (CRC) can be in the range greater than or equal to, or greater than, any one of the above lower limits; or in the range less than or equal to, or less than, any one of the above upper limits while being greater than or equal to, or greater than, any one of the above lower limits. The centrifuge retention capacity can be evaluated by the method described in "1. Evaluation of Centrifuge Retention Capacity (CRC)" in the Examples section of this specification.

[0023] The lower limit of the water content of the polymer can be about 40 wt%, 45 wt%, 50 wt%, or 55 wt%, and the upper limit thereof can be about 70 wt%, 65 wt%, or 60 wt%. The water content can be in the range greater than or equal to, or greater than, any one of the above lower limits; or in the range less than or equal to, or less than, any one of the above upper limits while being greater than or equal to, or greater than, any one of the above lower limits. The water content is the content of water contained in the polymer relative to the total weight of the polymer to be measured, and it can be calculated based on the weight of the polymer containing water and the weight of the dry polymer. For example, the water content can be calculated by the weight loss due to evaporation of water in the polymer during a drying process that raises the temperature of the polymer in a crumb state by infrared heating. The drying process for measuring the water content can include raising the temperature from room temperature to about 50°C, and then performing vacuum drying for about 6 hours while maintaining the temperature at 50°C.

[0024] The lower limit of the Absorbency Under Pressure (AUP) of the polymer according to the EDANA (European Disposables and Nonwovens Association) method WSP 242.3 at 0.7 psi can be around 1.5 g / g, 2 g / g, 2.5 g / g, 3 g / g, 3.5 g / g, 4 g / g, 4.5 g / g, 5 g / g or 5.5 g / g, and its upper limit can be around 40 g / g, 35 g / g, 30 g / g, 20 g / g, 15 g / g, 10 g / g, 8 g / g, 6 g / g or 4 g / g. The Absorbency Under Pressure (AUP) can be in the range greater than or equal to, or greater than any one of the above lower limits; or in the range less than or equal to, or less than any one of the above upper limits while being greater than or equal to, or greater than any one of the above lower limits.

[0025] If the polymer exhibits at least one of the characteristics of the water content, the Centrifugal Retention Capacity and the Absorbency Under Pressure, it can be defined as an absorbent polymer. The polymer can exhibit any one of the water content, the Centrifugal Retention Capacity and the Absorbency Under Pressure, or can exhibit two or more, or all of them.

[0026] The polymer can be a biodegradable polymer.

[0027] For example, the lower limit of the biodegradability of the polymer can be around 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94%, 96%, 98% or 99%, and its upper limit can be around 100%, 98%, 96%, 94%, 92%, 90%, 88%, 86%, 84%, 82%, 80%, 78% or 76%. The biodegradability can be in the range greater than or equal to, or greater than any one of the above lower limits; or in the range less than or equal to, or less than any one of the above upper limits while being greater than or equal to, or greater than any one of the above lower limits. The polymer can exhibit the biodegradability before or after crosslinking.

[0028] As is well known, the term polymer can mean a high molecular weight material formed by covalently bonding two or more unit bodies (such as monomers). A polymer can mean a material that contains a structure in which two or more unit bodies are covalently bonded and at the same time exhibits a certain level or higher molecular weight. At this time, the range of the molecular weight will be described below.

[0029] The polymer can be a polysaccharide component, or can contain a polysaccharide component.

[0030] The term polysaccharide component means a polysaccharide or a mixture of polysaccharides. In the case of a mixture of polysaccharides, the mixture can be a mixture of one type of polysaccharide, or a mixture of two or more types of polysaccharides. Here, two or more types of polysaccharides can also mean different types of polysaccharides, and can also include polysaccharides of the same type but having different physical properties (such as molecular weight). The polysaccharide component contains only polysaccharides.

[0031] The term polysaccharide has the meaning known in the industry. Generally, a polysaccharide refers to a polymer molecule in which two or more monomer units are connected by covalent bonds. The covalent bond connecting the monomer units is usually a glycosidic bond.

[0032] Representative polysaccharides include starch, glycogen, cellulose, chitin or chitosan, etc.

[0033] The monomer units forming the polysaccharide can be biomolecules composed of carbon, hydrogen and oxygen, or biomolecules composed of carbon, hydrogen, oxygen and nitrogen. In this specification, the term biomolecule is interpreted to have the meaning commonly applied in the industry. Typically, as examples of biomolecules in the industry, monosaccharides such as glucose, galactose, fructose or xylose are known; disaccharides such as sucrose, lactose, maltose or trehalose; polyols such as sorbitol or mannitol; oligosaccharides such as maltodextrin, dextrin, raffinose, stachyose or oligofructose; and / or amino sugars such as glucosamine or N-acetylglucosamine; etc., but the types of biomolecules in this application are not limited to the foregoing.

[0034] The lower limit of the content of the polysaccharide or polysaccharide component in the polymer can be about 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 99 wt% or 99.5 wt%, and the upper limit thereof can be about 100 wt%, 98 wt%, 96 wt%, 94 wt%, 92 wt% or 90 wt%. This ratio can be in the range greater than or equal to, or greater than any one of the above lower limits; or in the range less than or equal to, or less than any one of the above upper limits; or in the range less than or equal to, or less than any one of the above upper limits while greater than or equal to, or greater than any one of the above lower limits.

[0035] The ratio of the polysaccharide component in the polymer is not particularly limited, but as the ratio increases, the biodegradability of the polymer increases. However, in the case of conventional absorbent materials using the polysaccharide component, if the ratio of the polysaccharide component is excessively increased in consideration of biodegradability, there is a problem of reduced absorption capacity. However, the polymer can stably achieve the desired absorption capacity while maintaining the ratio of the polysaccharide component at a high level.

[0036] If a polymer (e.g., a polysaccharide or a polysaccharide component) is in a cross-linked state and has absorbent capacity, the relevant polymer can be referred to as a hydrogel polymer or a hydrogel. In one example, the polymer can also be in the form of a powder formed by a grinding process or the like.

[0037] The polymer in the form of a powder can also be applied to additional processes such as surface cross-linking.

[0038] The polymer or the polysaccharide or the polysaccharide component can be in a cross-linked state. Cross-linking means a state in which two or more molecules of the polymer, polysaccharide or polysaccharide component are connected by one or more chemical bonds. Typically, cross-linking is formed by a compound called a so-called cross-linking agent. Such a cross-linking agent has two or more functional groups capable of reacting with the polymer, polysaccharide or polysaccharide component, and the cross-linked structure can be formed through such functional groups.

[0039] In one example, cross-linking of the polymer can be carried out without using a cross-linking agent or while minimizing the amount used. Most of the cross-linking agents known to date for forming SAPs are non-biodegradable or poorly biodegradable substances, such that in most cases, even when a biodegradable polysaccharide or polysaccharide component is used as the polymer, its biodegradability is not effectively exhibited after cross-linking. Therefore, if cross-linking is carried out without using a cross-linking agent or while minimizing the amount used, a polymer can be obtained in which the biodegradability of the material is achieved while exhibiting the desired absorbent capacity.

[0040] In this specification, the above-mentioned cross-linking carried out without using a cross-linking agent or while minimizing the amount used can be referred to as self-cross-linking.

[0041] In one example, the polymer can contain a self-cross-linked polysaccharide or a self-cross-linked polysaccharide component.

[0042] For example, based on the total weight of the polymer, the lower limit of the ratio of the self-cross-linked polysaccharide or the self-cross-linked polysaccharide component in the polymer can be about 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 97 wt%, 99 wt% or 99.5 wt%, and the upper limit thereof can be about 100 wt%, 98 wt%, 96 wt%, 94 wt%, 92 wt% or 90 wt%. The ratio can be in the range greater than or equal to, or greater than, any one of the above lower limits; or in the range less than or equal to, or less than, any one of the above upper limits while being greater than or equal to, or greater than, any one of the above lower limits.

[0043] Based on the total weight of the self-crosslinked polymer, self-crosslinked polysaccharide or self-crosslinked polysaccharide component, the upper limit of the ratio of the crosslinking agent in the self-crosslinked polymer, self-crosslinked polysaccharide or self-crosslinked polysaccharide component can be about 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt%, 0.5 wt%, 0.1 wt%, 0.05 wt%, 0.01 wt%, 0.005 wt%, 0.001 wt%, 0.0005 wt% or 0.0001 wt%, and the lower limit thereof can be about 0 wt%. The ratio of the crosslinking agent can be in the range less than or equal to, or less than any one of the above upper limits; or in the range less than or equal to, or less than any one of the above upper limits and greater than or equal to, or greater than any one of the above lower limits. Herein, the crosslinking agent is a substance that forms a chemical bond connecting the polymer, polysaccharide or polysaccharide component, and it means a substance other than the polymer, polysaccharide or polysaccharide component.

[0044] In this way, when crosslinking is carried out without using a crosslinking agent or while minimizing the usage amount, the biodegradability of the material itself can be maximally utilized while ensuring the absorption capacity. Since polysaccharides or polysaccharide components, which are generally known biodegradable materials, have low crosslinking efficiency, it is not easy to obtain a polymer having desired properties (such as absorption capacity). In the present specification, specific types of polysaccharides or polysaccharide components that can be effectively self-crosslinked without using a crosslinking agent and crosslinking methods are disclosed. These polysaccharides or polysaccharide components can have excellent physical properties (such as absorption capacity) in a self-crosslinked state while having excellent biodegradation characteristics.

[0045] Self-crosslinking of the polysaccharide component can be carried out using a so-called acidic polysaccharide component. The acidic polysaccharide component is a polysaccharide component having an acidic group. Examples of the acidic group can include a carboxyl group, a phosphoric acid ester group, a phosphorous acid ester group and / or a sulfuric acid ester group, or a salt thereof.

[0046] For effective self-crosslinking, the acidic polysaccharide component can be adjusted. For example, in the polysaccharide component, F in the following Equation 1 can be greater than or equal to a certain level. F is the value of the polysaccharide component before self-crosslinking.

[0047] [Equation 1]

[0048] F = AP × DS × Log(Mw)

[0049] In Equation 1, AP is the ratio of amylopectin in the polysaccharide component, DS is the degree of substitution of the polysaccharide component, and Mw is the molecular weight of the polysaccharide component.

[0050] In Equation 1, AP is the ratio of amylopectin in the polysaccharide component and is measured in the manner described in "3. Measurement of Amylose and Amylopectin Contents" in the Examples section of this specification. When the sum (Am + Ap) of the weight of amylose (Am) and the weight of amylopectin (Ap) in the polysaccharide component is converted to 100, AP is calculated as Ap / (Am + Ap). As is known, the polysaccharide component is usually mainly composed of amylose and amylopectin. Amylose and amylopectin are composed of glucose molecules linked by glycosidic bonds, where amylose has a linear chain structure while amylopectin has relatively short and highly branched chains. In addition, amylose is relatively easy to crystallize compared to amylopectin, and amylopectin has a relatively higher solubility in water than amylose. Therefore, the ratio of amylose to amylopectin in the polysaccharide component can be related to the absorption capacity and biodegradability of the polysaccharide component. In addition, the ratio of amylopectin in the polysaccharide component is related to the spatial structure that affects the steric hindrance of the relevant polysaccharide component, and the self-crosslinking efficiency may be affected according to such a spatial structure.

[0051] The degree of substitution DS in Equation 1 is a value representing the degree to which the hydroxyl groups present in each unit contained in the polysaccharide component have been substituted by acidic groups, and is the average value of each unit present in the polysaccharide component. For example, if the unit is a glucose unit, there are three hydroxyl groups present in the relevant unit before modification, and thus, if all hydroxyl groups are replaced by acidic groups, the degree of substitution of the relevant unit is 3. The degree of substitution of the polysaccharide component is the average value of the degrees of substitution of each unit present in the relevant polysaccharide component, such that, for example, in a polysaccharide component containing 5 glucose units, if the degrees of substitution of each unit are 1, 0, 2, 3, and 1, the degree of substitution of the polysaccharide becomes 1.4, which is the average value. This degree of substitution can be determined by 1 1H NMR analysis of the polysaccharide. Since the hydroxyl groups and substituted functional groups present in the polysaccharide can be quantified by 1 1H NMR analysis, the degree of substitution can be determined, and if necessary, the 1 1H NMR analysis results of the polysaccharide before modification can be considered to calculate the degree of substitution.

[0052] The method for performing 1 1H NMR analysis is described in "4. NMR Analysis" in the Examples section of this specification, and an example of calculating the degree of substitution DS based on the results is described in Preparation Example 1 in the above Examples section.

[0053] In Equation 1, Mw is the molecular weight of the polysaccharide component, and the molecular weight related to bulk is also related to the spatial structure related to self-crosslinking. The molecular weight is evaluated in the manner described in "2. Measurement of the Molecular Weight of the Polysaccharide Component" in the Examples section of this specification.

[0054] By adjusting F in Equation 1 determined by these factors, a polysaccharide component in which self-crosslinking is effectively carried out can be obtained.

[0055] The lower limit of F in Equation 1 can be around 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9 or 9.5, and its upper limit can be around 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9.5, 9, 8.5, 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, 3.5, 3 or 2.5. F can be in a range greater than or equal to, or greater than, any one of the above lower limits; or in a range less than or equal to, or less than, any one of the above upper limits and greater than or equal to, or greater than, any one of the above lower limits.

[0056] The polysaccharide component with F in the above range can exhibit the property of being able to exhibit excellent absorption ability, and exhibit a spatial structure suitable for crosslinking while having a substituent in an amount capable of effective self-crosslinking. In addition, such a polysaccharide component can exhibit excellent absorption ability after crosslinking.

[0057] It is also possible to adjust the ranges of Mw, DS, and AP for determining F in Equation 1 to appropriate levels.

[0058] For example, the lower limit of Mw in Equation 1 can be around 50,000, 100,000, 150,000, 200,000, 250,000, 300,000, 500,000, 1,000,000, 5,000,000, 10,000,000, 15,000,000, 20,000,000, 25,000,000, 30,000,000, 35,000,000, 40,000,000, 45,000,000, 50,000,000, 55,000,000, 60,000,000 or 64,000,000, and its upper limit can be 10,000,000,000, 9,500,000,000, 9,000,000,000, 8,500,000,000, 8,000,000,000, 7,500,000,000, 7,000,000,000, 6,500,000,000, 6,000,000,000, 5,500,000,000, 5,000,000,000, 4,500,000,000, 4,000,000,000, 3,500,000,000, 3,000,000,000, 2,500,000,000, 2,000,000,000, 1,500,000,000, 1,000,000,000, 950,000,000, 900,000,000, 850,000,000, 800,000,000, 750,000,000, 700,000,000, 650,000,000, 600,000,000, 550,000,000, 500,000,000, 450,000,000, 400,000,000, 350,000,000, 300,000,000, 250,000,000, 200,000,000, 150,000,000, 100,000,000, 95,000,000, 90,000,000, 85,000,000, 80,000,000, 75,000,000, 70,000,000, 65,000,000, 60,000,000, 55,000,000, 50,000,000, 45,000,000, 40,000,000, 35,000,000, 30,000,000, 25,000,000, 20,000,000, 15,000,000, 10,000,000, 9,500,000, 9,000,000, 8,500,000, 8,000,000, 7,500,000, 7,000,000, 6,500,000, 6,000,000, 5,500,000, 5,000,000, 4,500,000, 4,000,000, 3,500,000, 3,000,000, 2,500,000, 2,000,000, 1,500,000, 1,000,000, 950,000, 900,000, 850,000, 800,000, 750,000, 700,000, 650,000, 600,000, 550,000, 500,000, 450,000, 400,000 or about 350,000. Mw can be in the range greater than or equal to, or greater than any one of the above lower limits; or in the range less than or equal to, or less than any one of the above upper limits while greater than or equal to, or greater than any one of the above lower limits.,

[0059] In Equation 1, the lower limit of DS can be about 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55 or 1.6, and its upper limit can be about 2.5, 2.45, 2.4, 2.35, 2.3, 2.25, 2.2, 2.15, 2.1, 2.05, 2, 1.95, 1.9, 1.85, 1.8, 1.75, 1.7, 1.65, 1.6, 1.55, 1.5, 1.45, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.1, 1.05, 1, 0.95, 0.9, 0.85, 0.8, 0.75, 0.7, 0.65, 0.6, 0.55, 0.5, 0.45 or 0.4. DS can be in the range less than or equal to, or less than any one of the above upper limits while greater than or equal to, or greater than any one of the above lower limits.,

[0060] In Equation 1, the lower limit of AP can be about 0.6, 0.65, 0.7, 0.72, 0.74, 0.76 or 0.78, and its upper limit can be about 0.95, 0.9, 0.85, 0.8 or 0.75. AP can be in the range less than or equal to, or less than any one of the above upper limits while greater than or equal to, or greater than any one of the above lower limits.,

[0061] The self - crosslinking of the polysaccharide component can be carried out, for example, by using a polysaccharide component having a carboxyl group or a salt of a carboxyl group as an acidic group in the above - mentioned acidic polysaccharide component. Since the polysaccharide itself contains hydroxyl groups, the self - crosslinking can be carried out by an esterification reaction between the hydroxyl groups contained in one polysaccharide molecule and the carboxyl group or the salt of the carboxyl group contained in the acidic polysaccharide.,

[0062] The type of the polysaccharide component having a carboxyl group or a salt of a carboxyl group is not particularly limited. For example, self-crosslinking can be carried out by applying a polysaccharide having a carboxyl group or the like itself, such as so-called CMC (carboxymethyl cellulose) (which corresponds to a lignocellulosic polysaccharide), or by introducing a carboxyl group or a salt thereof into a polysaccharide through a process such as maleation or carboxyalkylation.

[0063] The self-crosslinked polysaccharide component may include a polymer chain containing monosaccharide units linked by glycosidic bonds (i.e., the polysaccharide chain to be crosslinked), and a crosslinking bond connecting the polymer chains.

[0064] At this time, the crosslinking bond may be connected to the monosaccharide unit.

[0065] Here, the crosslinking bond may be a bond represented by the following formula 1.

[0066] [Formula 1]

[0067]

[0068] In formula 1, L1 is an alkylene group, an alkylidene group or a bond of the following formula 2, and L2 is represented by a single bond or -(CH2)-O-.

[0069] [Formula 2]

[0070]

[0071] In formula 1, the oxygen atom shown on the leftmost side may be directly connected to the monosaccharide unit of the polymer chain.

[0072] In formula 1, when L2 is a single bond, L2 does not exist. That is, in formula 1, when L2 exists, L2 may be directly connected to the monosaccharide unit of the polymer chain, and when L2 is a single bond, the oxygen atom on the left side of L2 in formula 1 may be directly connected to the monosaccharide unit.

[0073] In formula 1, the alkylene group means a functional group in which two hydrogen atoms are separated from an alkane and connected to another object, where the two hydrogen atoms are separated from different carbon atoms of the alkane. Such an alkylene group may be an alkylene group having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms. Such an alkylene group may be linear, branched or cyclic. Such an alkylene group may also be optionally substituted with one or more substituents.

[0074] In Formula 1, alkylidene means a functional group in which two hydrogen atoms are separated from an alkane and connected to another object, and it means a structure in which two hydrogen atoms are separated from one carbon atom of an alkane. Such an alkylidene can be an alkylidene having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Such an alkylidene can be linear, branched, or cyclic. Such an alkylidene can also optionally be substituted with one or more substituents.

[0075] In the case of self-crosslinking of a polysaccharide with a polysaccharide having a carboxyl group or its salt itself, such as CMC (carboxymethyl cellulose), or a polysaccharide having a carboxyl group or its salt introduced by carboxyalkylation or the like, L1 in Formula 1 can generally be an alkylene or an alkylidene. In Formula 1, when L1 is a functional group of Formula 2, it is a case of self-crosslinking through a carboxyl group or its salt introduced by so-called maleation or the like.

[0076] In Formula 1, when L1 is Formula 2, the carbon atom of the carbonyl group in Formula 2 is connected to the oxygen atom on the left side of L1 in Formula 1, and the carbon atom on the right side of the carbon-carbon double bond in Formula 2 is connected to the carbon atom of the carbonyl group on the right side of L1 in Formula 1.

[0077] One or more bonds of Formula 1 can be present in the self-crosslinked polysaccharide component.

[0078] The type of the monosaccharide unit is not particularly limited, and it can typically be a monosaccharide unit constituting a polysaccharide. For example, such a monosaccharide unit can be a glucose unit, a glucosamine unit, an N-acetylglucosamine unit, etc.

[0079] Such a monosaccharide unit generally contains a ring structure containing carbon atoms and oxygen atoms as ring-constituting atoms. The ring structure of the monosaccharide unit is generally a six-membered ring structure (when the ring atoms include only 5 carbon atoms and 1 oxygen atom), but it can also have a ring structure of six or more members. When the ring structure is a six- or more-membered ring, the ring atoms can be carbon atoms, or heteroatoms such as oxygen atoms or nitrogen atoms.

[0080] In the case of a self-crosslinked structure, the bond of Formula 1 above can be directly connected to the carbon atom of the ring structure of the monosaccharide unit, or can be connected via a methylene group (-CH2-).

[0081] At least one or both of the leftmost oxygen atom and the rightmost oxygen atom in Formula 1 (if L2 is a single bond, it means the oxygen atom connected to the right side of the carbonyl group, and if L2 is not a single bond, it means the oxygen atom of -(CH2)-O-) can be directly connected to the carbon atom of the ring structure, or can be connected via a methylene group (-CH2-).

[0082] Here, the case of being connected via a methylene (-CH2-) means that there is only a methylene (-CH2-) between the leftmost oxygen atom in Formula 1 above or the rightmost oxygen atom in Formula 1 (if L2 is a single bond, it means the oxygen atom connected to the right side of the carbonyl group, and if L2 is not a single bond, it means the oxygen atom of -(CH2)-O-) and the carbon atom of the ring structure.

[0083] In this case, more specifically, the polysaccharide component may contain a unit represented by the following Formula 3.

[0084] [Formula 3]

[0085]

[0086] In Formula 3, R1 is a hydroxyl group, an amino group, -L5-C(=O)-OH, -L5-C(=O)-O - , or a functional group of the following Formula 4, R3 is a hydroxyl group, -L5-C(=O)-OH, -L5-C(=O)-O - , or a functional group of the following Formula 4, and one of L3 and L4 is a single bond and the other is CHR2, where R2 is a hydroxyl group, -L5-C(=O)-OH, -L5-C(=O)-O - , or a functional group of the following Formula 4, and L5 is an alkylene group or an alkylidene group, provided that any one of R1 to R3 is the oxygen atom of the bond in Formula 1 above (except for the oxygen atom present in the carbonyl group).

[0087] [Formula 4]

[0088]

[0089] In Formula 4, M1 is hydrogen or a metal, and when M1 is a metal, the above O-M1 bond is an ionic bond.

[0090] The functional group -L5-C(=O)-OH or -L5-C(=O)-O in Formula 3 - can be, for example, a carboxyl group introduced by carboxyalkylation or a functional group in which the carboxyl group is ionized, etc., and Formula 4 is a functional group introduced by maleation.

[0091] In Formula 3, the specific types of the alkylene group and the alkylidene group are the same as those in Formula 1.

[0092] These functional groups are introduced to form crosslinking bonds by participating in the above self-crosslinking reaction, but not all of the introduced functional groups can participate in the crosslinking reaction, and in this case, some functional groups can remain.

[0093] Here, the case where either L3 or L4 is a single bond means the absence of either L3 or L4. For example, in the absence of L3, the carbon atoms connected to the left and right sides of L3 in Formula 3 are directly connected, and in the absence of L4, the carbon atoms connected to the left and right sides of L4 in Formula 3 are directly connected.

[0094] The case where the other of L3 and L4 is CHR2 means the following case: in Formula 3, either of L3 and L4 is a carbon atom, and a substituent R2 is substituted on this carbon atom.

[0095] The case where any one of R1 to R3 in Formula 3 is an oxygen atom of the bond of Formula 1 (except for the oxygen atom present in the carbonyl group) means that any one of R1 to R3 is an oxygen atom connecting the polysaccharide of the bond of Formula 1, where this oxygen atom means either the leftmost oxygen atom and the rightmost oxygen atom in Formula 1 (if L2 is a single bond, it means the oxygen atom connected to the right side of the carbonyl group, and if L2 is not a single bond, it means the oxygen atom of -(CH2)-O-).

[0096] As described above, the self-crosslinked structure can be achieved by carrying out an esterification reaction between acidic polysaccharides, especially polysaccharides having a carboxyl group or its salt. In such a self-crosslinking reaction, as described below, by particularly adjusting the pH in the reaction conditions, a polymer having balanced absorption characteristics can be provided.

[0097] As the acidic polysaccharide, a polysaccharide having a carboxyl group or its salt by itself such as CMC (carboxymethyl cellulose) can be used, or a polysaccharide in which a carboxyl group or its salt is introduced by a process such as maleation or carboxyalkylation can be used, and in order to achieve the above-mentioned degree of substitution and for effective self-crosslinking, a polysaccharide in which a carboxyl group or its salt has been introduced by a denaturation process can be used.

[0098] The method for introducing a carboxyl group or its salt into the polysaccharide is not particularly limited. For example, in order to introduce a functional group such as Formula 4, a so-called maleation process can be carried out. Such a process is a process of reacting a polysaccharide with an unsaturated dicarboxylic acid or its anhydride to replace the hydroxyl group present in the monomer unit of the polymer with a functional group, and examples of the dicarboxylic acid or its anhydride can be exemplified as maleic acid or maleic anhydride, etc., but are not limited thereto, and salts of maleic acid, etc. can also be applied. The method for carrying out the maleation process is known.

[0099] The carboxyalkylation process can be carried out by reacting a polysaccharide component with an alkanoic acid or a haloalkanoic acid or a salt of an alkanoic acid or a haloalkanoic acid. For example, after protonating the hydroxyl group of the polysaccharide component by an additive such as NaOH, a carboxyl group or its salt can be introduced into the polysaccharide component by reaction with an alkanoic acid.

[0100] As is known, alkanoic acids are aliphatic acids derived from alkanes, and haloalkanoic acids mean acids in which at least one hydrogen atom of the alkanoic acid is replaced by a halogen atom (such as chlorine, fluorine, or bromine, etc.). In the present specification, the alkanoic acids, haloalkanoic acids, salts of alkanoic acids, and / or salts of haloalkanoic acids applied in the carboxyalkylation process may be referred to as treating agents.

[0101] As the alkanoic acid or haloalkanoic acid used as a treating agent, an alkanoic acid or haloalkanoic acid having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms can be used, and typically acetic acid or chloroacetic acid can be used.

[0102] The salts of haloalkanoic acids or alkanoic acids can be alkali metal salts or alkaline earth metal salts of haloalkanoic acids or alkanoic acids having the same number of carbon atoms as above.

[0103] By reacting the treating agent with the polysaccharide under appropriate conditions, acidic groups (such as carboxyl groups) can be introduced into the polysaccharide.

[0104] The process of introducing acidic groups can be carried out according to known methods, and if necessary, additional processes can be carried out or the conditions of the process can be adjusted to effectively carry out the carboxyalkylation process.

[0105] For example, the above process can be carried out on a mixture in which the treating agent and the hydroxide are dispersed in a solvent. Here, as the solvent, for example, an aqueous solvent such as water can be used. Here, as the water, tap water, distilled water, deionized water, or purified water, etc. can be used. Here, as the hydroxide, ammonium hydroxide or metal hydroxide can be used, and as the metal hydroxide, sodium hydroxide, potassium hydroxide, or lithium hydroxide, etc. can be used, but it is not limited thereto.

[0106] Such a metal hydroxide can act as an additive for protonating the hydroxyl groups of the polysaccharide component.

[0107] In the reaction of the mixture, for example, first the gelatinization reaction of the polysaccharide is carried out in the mixture, and then the introduction of carboxyl groups, etc. by the treating agent is carried out.

[0108] In the above process, the degree of substitution can be controlled by controlling the amount of the treating agent in the mixture. In the above reaction, about 90% by weight of the treating agent usually applied reacts with the polysaccharide component, thereby introducing carboxyl groups, etc. into the polysaccharide component. Therefore, considering this, by applying an appropriate level of the treating agent relative to the polysaccharide component used, the desired degree of substitution can be achieved. To achieve a degree of substitution higher than a certain level, the preparation and reaction of the mixture can be repeated multiple times, and if necessary, the ratio of the hydroxide applied together can also be controlled.

[0109] For example, the lower limit of the ratio of hydroxide in the mixture can be about 0.5 equivalents, 0.6 equivalents, or 0.7 equivalents, and the upper limit thereof can be about 1.5 equivalents, 1.15 equivalents, 1.1 equivalents, 1 equivalent, 0.9 equivalents, or 0.8 equivalents. The equivalent can be within a range less than or equal to, or less than any of the above upper limits; or within a range less than or equal to, or less than any of the above upper limits and greater than or equal to, or greater than any of the above lower limits. Herein, the equivalent can be obtained by the formula A / B, where A is the number of moles of hydroxide present in the mixture, and B is the value calculated as C / 162.14, where C is the weight of the polysaccharide in the mixture (unit: g). Herein, 162.14 is the molar mass (g / mol) of the anhydroglucose unit. Typically, the polysaccharide contains anhydroglucose units or their derivatives, or units having a similar molar mass. Thus, in the present application, if the amount of the polysaccharide used to obtain the above equivalent is typically applied by the formula C / 162.14, the reaction can be carried out according to the purpose by specifying the equivalent within the above range according to such an application method. By maintaining the amount of hydroxide used within the above range, the reaction efficiency and workability can be stably maintained while keeping the substitution efficiency of carboxyl groups and the like within the desired range, and unnecessary side reactions and the like can be suppressed.

[0110] The lower limit of the ratio of the treatment agent in the mixture can be about 0.5 equivalents, 0.6 equivalents, or 0.7 equivalents, and the upper limit thereof can be about 1.5 equivalents, 1.15 equivalents, 1.1 equivalents, 1 equivalent, 0.9 equivalents, or 0.8 equivalents. The equivalent can be within a range less than or equal to, or less than any of the above upper limits; or within a range less than or equal to, or less than any of the above upper limits and greater than or equal to, or greater than any of the above lower limits. Herein, the equivalent can be obtained by the formula D / B, where D is the number of moles of the treatment agent present in the mixture, and B is the same as the formula for calculating the equivalent of hydroxide. By maintaining the amount of the treatment agent used within the above range, the reaction efficiency and workability can be stably maintained while keeping the substitution efficiency of carboxyl groups and the like within the desired range, and unnecessary side reactions and the like can be suppressed.

[0111] The lower limit of the ratio (A / B) of the number of moles (A) of the hydroxide in the mixture to the number of moles (D) of the treating agent can be around 0.5, 0.6, 0.7, 0.8, 0.9, or 0.95, and the upper limit thereof can be around 1.5, 1.4, 1.3, 1.2, 1.1, or 1.05. The ratio can be in the range less than or equal to, or less than, any of the above upper limits; or in the range less than or equal to, or less than, any of the above upper limits and greater than or equal to, or greater than, any of the above lower limits. By maintaining the above ratio, a polysaccharide capable of stable self-crosslinking can be obtained while keeping the substitution efficiency of carboxyl groups and the like within a desired range, the reaction efficiency and workability can be stably maintained, and unnecessary side reactions and the like can be suppressed.

[0112] In the above reaction, the mixture can be present in the reactor where the reaction is carried out at a predetermined ratio. For example, based on the total volume of the reactor, the lower limit of the ratio of the volume of the mixture in the reactor can be around 70%, 75%, 76%, or 77%, and the upper limit thereof can be around 95%, 94%, 93%, or 92%. The ratio can be in the range less than or equal to, or less than, any of the above upper limits; or in the range less than or equal to, or less than, any of the above upper limits and greater than or equal to, or greater than, any of the above lower limits. By maintaining the above ratio, the torque in the reactor can be stably maintained, a polysaccharide capable of stable self-crosslinking can be obtained while keeping the substitution efficiency of carboxyl groups and the like within a desired range, the reaction efficiency and workability can be stably maintained, and unnecessary side reactions and the like can be suppressed.

[0113] Carboxyalkylation can be carried out by maintaining the mixture at an appropriate temperature for a constant time or longer, and a desired acidic polysaccharide can be obtained. In this process, if necessary, additional processes such as stirring can be carried out.

[0114] This specification also discloses a method for producing a polymer by a step of self-crosslinking an acidic polysaccharide component (such as the above acidic polysaccharide component).

[0115] As the acidic polysaccharide component, the above components can be used. Immediately after introducing acidic groups such as carboxyl groups into the polysaccharide component by the above reaction, the self-crosslinking process can also be carried out, and if necessary, after recovering the polysaccharide component, the self-crosslinking process can be carried out. Recovering the polysaccharide component can include a process of dissolving the reactants produced by the reaction in water and precipitating them with an organic solvent such as alcohol, and in addition, various methods can also be applied.

[0116] The acidic polysaccharide component can have the range of F in Equation 1 and the values of AP, DS, and Mw in Equation 1 as described above.

[0117] The method for self-crosslinking is not particularly limited, but for effective self-crosslinking, it can be carried out by dispersing an acidic polysaccharide in a solvent and then maintaining the pH within a predetermined range.

[0118] In the above process, an aqueous solvent such as water can also be used as the solvent, and tap water, distilled water, deionized water, purified water, etc. can be used as water.

[0119] Even during self-crosslinking, it may be suitable to use basically only an aqueous solvent (such as water) as the solvent. Therefore, the solvent used during self-crosslinking may basically not contain other solvents except for the aqueous solvent (such as water). At this time, the case of basically not containing other solvents may mean that the upper limit of the content of other solvents in the solvent except for the aqueous solvent (such as water) is about 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt%, 0.5 wt%, 0.1 wt%, 0.05 wt%, 0.01 wt%, 0.005 wt% or 0.001 wt%, and its lower limit is about 0 wt%. This ratio can be within the range less than or equal to, or less than any of the above upper limits; or within the range less than or equal to, or less than any of the above upper limits and greater than or equal to, or greater than any of the above lower limits.

[0120] The amount of the solvent applied in the above process can be an amount 5 to 15 times the weight of the polysaccharide applied. Dissolving the polysaccharide in the solvent can be carried out under room temperature and normal pressure conditions, but is not limited thereto.

[0121] Self-crosslinking can be carried out by dissolving the polysaccharide in a solvent and maintaining the pH at a constant level. If necessary, additional processes that can promote self-crosslinking, such as a stirring process, can also be carried out.

[0122] The lower limit of the pH maintained in the above process can be about 6, 6.1, 6.2, 6.3, 6.4 or 6.5, and its upper limit can be 7, 6.9, 6.8, 6.7, 6.6, 6.5, 6.4, 6.3, 6.2, 6.1 or 6. The pH can be within the range less than or equal to, or less than any of the above upper limits; or within the range greater than or equal to, or greater than any of the above lower limits; or within the range less than or equal to, or less than any of the above upper limits and greater than or equal to, or greater than any of the above lower limits. By maintaining this pH range, the desired self-crosslinking can be effectively carried out.

[0123] The method for maintaining the pH within the above range is not particularly limited. For example, if the pH within the above range is achieved by adding an acidic polysaccharide, self-crosslinking can be carried out in this state. If the desired pH is not achieved, the pH can be adjusted by adding an appropriate acid or base considering the desired pH. At this time, for example, hydroxides applied in carboxyalkylation can be used as the base, and hydrochloric acid or sulfuric acid, etc. can be used as the acid, but it is not limited thereto.

[0124] During the above reaction process, a catalyst can be added as needed. For example, an ester catalyst that promotes the reaction between carboxyl and hydroxyl groups can be added. As such a catalyst, 4-methylaminopyridine, magnesium acetate, tetra-n-butyl titanate, lead acetate, sodium acetate, potassium acetate, antimony trioxide, and / or N-methylimidazole, etc. can be used, but it is not limited thereto. The catalyst can be added in a catalytic amount. For example, relative to 1 mol of polysaccharide applied to the reaction, it can be used at a ratio within the range of 0.1 mol to 5 mol. The lower limit of the catalyst usage ratio can be about 0.1 mol, 0.5 mol, 1 mol, or 2 mol, and the upper limit thereof can be about 5 mol, 4.5 mol, 4 mol, or 3.5 mol. This ratio can be within a range less than or equal to, or less than any of the above upper limits; or within a range less than or equal to, or less than any of the above upper limits while being greater than or equal to, or greater than any of the above lower limits.

[0125] If necessary, the reaction can also be carried out in the presence of a heat stabilizer. As applicable heat stabilizers, organic or inorganic phosphorus compounds can be used, such as phosphoric acid, organic esters of phosphoric acid, phosphorous acid, or organic esters of phosphorous acid. For example, phosphoric acid, alkyl phosphates, or aryl phosphates commercially known as heat stabilizers can be used.

[0126] If necessary, the reaction can also be carried out in the presence of additives (such as thickeners, plasticizers, storage stabilizers, and / or antioxidants).

[0127] The crosslinking reaction can be carried out at a predetermined temperature. For example, the lower limit of the reaction temperature can be about 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C, or 120 °C, and the upper limit thereof can be about 300 °C, 280 °C, 260 °C, 240 °C, 220 °C, 200 °C, 180 °C, 160 °C, 140 °C, 130 °C, 125 °C, or 125 °C. The temperature can be within a range less than or equal to, or less than any of the above upper limits while being greater than or equal to, or greater than any of the above lower limits. The reaction temperature can be achieved by methods such as hot air supply, infrared irradiation, microwave irradiation, or ultraviolet irradiation.

[0128] The time for the reaction is not particularly limited. For example, the lower limit of the reaction time can be about 30 minutes, 60 minutes, 90 minutes, 120 minutes, 150 minutes or 180 minutes, and the upper limit thereof can be about 500 minutes, 480 minutes, 460 minutes, 440 minutes, 420 minutes, 400 minutes, 380 minutes, 360 minutes, 340 minutes, 320 minutes, 300 minutes, 280 minutes, 260 minutes, 240 minutes, 220 minutes, 200 minutes or 180 minutes. The time can be within the range of being shorter than or equal to, or shorter than any one of the above upper limits while being longer than or equal to, or longer than any one of the above lower limits.

[0129] The desired self-crosslinked polysaccharide component can be obtained by the above method.

[0130] After such a crosslinking process, known additional processes can be carried out as needed. For example, processes such as recovering the self-crosslinked polysaccharide component, drying process, grinding process and / or surface treatment process of the polysaccharide can be carried out.

[0131] The polymer can contain the polysaccharide component as described above, and if necessary, can also contain other components. Examples of other components that can be included together with the polysaccharide are not particularly limited, but can be exemplified as additional treatment agents for the polysaccharide component, or polymers different from the polysaccharide component, etc.

[0132] For example, the polymer is in powder form and can also contain a surface treatment agent bound to the powder surface, etc. Such a surface treatment agent can help ensure the absorption capacity under pressure, etc. by improving the gel strength of the powder.

[0133] Since the polymer exhibits excellent absorbency and biodegradability at the same time, it can be used in various applications.

[0134] For example, the polymer can be used as an absorbent material for sanitary products (such as diapers or sanitary napkins) or other applications that require absorption. If necessary, the polymer can also be further crosslinked, surface-treated or physically ground to improve the efficiency of being used as a sanitary product or absorbent material.

[0135] Therefore, this specification discloses an absorbent material or a sanitary product (such as diapers, sanitary napkins, etc.) containing the said polymer.

[0136] The specific method for forming the absorbent material or sanitary product by applying the said polymer is not particularly limited. For example, the method for forming the absorbent material or sanitary product by applying the existing SAP can be used in the same way.

[0137] Beneficial effects

[0138] This specification discloses polymers. The polymers can be absorbent polymers for forming so-called SAP. By adjusting the materials applied to the cross-linking process for forming SAP and the conditions of the cross-linking process, such polymers can be formed even without using a so-called cross-linking agent or minimizing its usage amount, thereby exhibiting excellent absorption capacity. The polymers can be formed by cross-linking biodegradable materials even without using a cross-linking agent or minimizing its usage amount, thereby exhibiting the maximum biodegradability of the materials. This specification also discloses the uses of the polymers. Description of the Drawings

[0139] Figure 1 1H NMR spectrum of the acidic polysaccharide of Preparation Example 1 1 1H NMR spectrum.

[0140] Figure 2 1H NMR spectrum of the acidic polysaccharide of Example 3 1 1H NMR spectrum.

[0141] Figure 3 1H NMR spectrum of the acidic polysaccharide of Example 4 1 1H NMR spectrum.

[0142] Figure 4 1H NMR spectrum of the acidic polysaccharide of Example 5 1 1H NMR spectrum.

[0143] Figure 5 1H NMR spectrum of the acidic polysaccharide of Example 6 1 1H NMR spectrum.

[0144] Figure 6 1H NMR spectrum of the acidic polysaccharide of Example 7 1 1H NMR spectrum.

[0145] Figure 7 1H NMR spectrum of the acidic polysaccharide of Example 8 1 1H NMR spectrum.

[0146] Figure 8 1H NMR spectrum of the acidic polysaccharide of Example 9 1 1H NMR spectrum.

[0147] Figure 9 1H NMR spectrum of the acidic polysaccharide of Comparative Example 7 1 1H NMR spectrum.

[0148] Figure 10 1H NMR spectrum of the acidic polysaccharide of Comparative Example 8 1 1H NMR spectrum.

[0149] Figure 11 1H NMR spectrum of the acidic polysaccharide of Comparative Example 11 1 1H NMR spectrum. Detailed Description of the Invention

[0150] In the following, polymers and the like disclosed in this specification will be described in detail by way of examples and comparative examples, but the scope of polymers and the like is not limited by the following examples.

[0151] 1. Evaluation of Centrifugal Retention Capacity (CRC)

[0152] CRC (Centrifugal Retention Capacity) is measured according to EDANA (European Disposables and Nonwovens Association) WSP 241.3. Approximately 0.2 g (W0) of the polymer is placed in a non-woven bag, sealed, and then immersed in a physiological saline solution. As the physiological saline solution, an aqueous NaCl solution with a concentration of 0.9 wt% is used. This state is maintained for about 30 minutes, and water is removed from the bag for 3 minutes under the condition of 250G using a centrifuge, and the mass (g, W2) of the bag is measured. The same operation is performed on the same non-woven bag without the polymer, and the mass (g, W1) is measured.

[0153] CRC (g / g) is calculated by substituting the measurement results into the following Equation A.

[0154] The evaluation is carried out under constant temperature and humidity conditions (23 ± 1 °C, relative humidity: 50 ± 10%).

[0155] [Equation A]

[0156] CRC (g / g) = {[W2 (g) - W1 (g)] / W0 (g)} - 1

[0157] 2. Measurement of the Molecular Weight of the Polysaccharide Component

[0158] The molecular weight was evaluated using flow FFF (field-flow fractionation)-MALS (Multiangle Light Scattering) method. This method is a method for measuring the molecular weight of a sample by connecting MALS, which measures the intensity of scattered light at different angles as a light scattering detector, to flow FFF. As the flow FFF / MALS device, the AF2000 device of Postnova was used. To measure the molecular weight, a sample for molecular weight measurement was placed in distilled water at a concentration of 5 mg / mL, dissolved in a hydrothermal reactor set at a temperature of 150 °C for 6 hours, and filtered (cellulose syringe filter) to prepare a sample. An aqueous solution of 0.1 M NH4OAc (ammonium acetate) was prepared and used as the mobile phase by filtering it using a solvent purification system. The molecular weight was measured while the sample flowed through the analysis channel (300 mm × 60 mm × 40 mm) under the conditions of a detector flow rate of 0.5 mL / min, an injection flow rate of 0.4 mL / min, an injection time of 10 minutes, a cross-flow rate of 0.5 mL / min, and a transition time of 1 minute.

[0159] 3. Measurement of the contents of amylopectin and amylose

[0160] The contents of amylopectin and amylose in the polysaccharide component were evaluated according to the method described in the paper (Potato Research 31(1988)241-246).

[0161] First, a sample (step 1) was prepared by dissolving approximately 5 mg of polysaccharide (starch) in approximately 1 mL of sterile water, and heated to 95 °C in a constant temperature water bath for approximately 15 minutes (step 2).

[0162] Subsequently, approximately 20 μl of the sample was placed in a cuvette (step 3), and approximately 980 μl of iodine solution was added thereto and mixed (step 4).

[0163] Subsequently, the absorbances of the sample mixed with the iodine solution were measured and recorded at wavelengths of 525 nm and 700 nm, respectively (step 5). The absorbances were measured using the OPTIZEN POP model of KLAB.

[0164] Approximately 20 μl of water was placed in another cuvette, 980 μl of iodine solution was added thereto, and mixed (step 6). For the solution in step 6, the absorbances at wavelengths of 525 nm and 700 nm were measured and recorded in the same manner as in step 5 (step 7).

[0165] The absorbance obtained in step 7 was subtracted from the absorbance obtained in step 5, and the ratio (%) of amylose was determined according to the following equation E (step 8).

[0166] [Equation E]

[0167]

[0168] In Equation E, PA is the ratio (%) of amylose, OD 700 is the value obtained by subtracting the absorbance measured at a wavelength of 700 nm in Step 7 from the absorbance measured at a wavelength of 700 nm in Step 5, and OD 525 is the value obtained by subtracting the absorbance measured at a wavelength of 525 nm in Step 7 from the absorbance measured at a wavelength of 525 nm in Step 5.

[0169] 4. NMR Analysis

[0170] 1H-NMR analysis for evaluating the degree of substitution of starch as a polysaccharide component is carried out in the following manner. A specimen for 1 1H-NMR analysis is prepared by dissolving the polysaccharide component in water, introducing methanol thereto, subsequently stirring the mixture, and then drying it after filtration. 1 50 mg of the obtained specimen is dissolved in a mixed solvent of 0.75 mL of D2O and 0.25 mL of D2SO4 as an NMR measurement solvent, and stirred at 90 °C for about 1 hour to prepare a sample. The sample turns dark yellow due to stirring. 1H NMR analysis is carried out at room temperature (about 25 °C) using a Varian Unity Inova (500 MHz) spectrometer with a triple resonance 5 mm probe. 1 1H NMR analysis is carried out using a Bruker avance Neo instrument. 1 1H NMR analysis.

[0171] Preparation Example 1. Preparation of Acidic Polysaccharide (A)

[0172] 100 g of starch and 400 mL of IPA (isopropyl alcohol) are introduced into a 500 mL round-bottom flask and stirred. The molecular weight of the starch is about 6.48×10 7Around g / mol, where the weight ratio of amylopectin (AP) to amylose (AM) (AP:AM) is about 79:21. The weight ratio of amylose and amylopectin can be adjusted in the manner shown in Example 16. Set the external temperature to 60 °C, and after waiting until temperature equilibrium is achieved, further introduce about 39 g of an aqueous NaOH solution with a concentration of about 40 wt%, and then further introduce 46 g of SMCA (Sodium MonochloroAcetate) into it. Stir it for 2 hours or longer while maintaining the heating state with the temperature set to 60 °C. Subsequently, cool it to room temperature (about 25 °C) and filter. Wash the solid obtained by filtration several times with an 80 wt% aqueous solution of MeOH (methanol) and dry it to prepare acidic polysaccharide (A).

[0173] Figure 1 For the polysaccharide component obtained in the above manner 1 1H NMR spectrum. The degree of substitution of this polysaccharide component was evaluated in the following manner. First, set the sum of the integrals of the peaks at 2.57 ppm, 2.58 ppm, 2.60 ppm, 2.64 ppm, 2.66 ppm, 3.15 ppm, 3.16 ppm, 3.33 ppm, and 3.34 ppm in the range of 2.5 ppm to 3.6 ppm of the spectrum as 1. Next, the degree of substitution at the 2-position carbon (2-DS) was obtained as the sum of the integrals of the peaks at 3.34 ppm and 3.33 ppm (doublet, 0.23) and 2.57 ppm and 2.58 ppm (doublet, 0.20), the degree of substitution at the 3-position carbon (3-DS) was obtained by dividing the integral value of the peaks at 2.39 ppm and 2.41 ppm (0.20) by 2, and the degree of substitution at the 6-position carbon (6-DS) was obtained by dividing the integral value of the peaks at 2.14 ppm and 2.15 ppm (0.19) by 2.

[0174] Subsequently, add all the above degrees of substitution together, and regard the value of 2-DS + 3-DS + 6-DS as the degree of substitution. The degree of substitution obtained by this method is about 0.6.

[0175] Example 1.

[0176] Disperse the acidic polysaccharide component of Preparation Example 1 in 10 times the amount of distilled water, and add 0.5 N HCl aqueous solution to adjust the pH of the mixture to about 6.0.

[0177] Subsequently, the pH-adjusted mixture was applied to a thickness of about 0.2 cm to 0.5 cm and heat-treated in an oven at a temperature of about 120 °C for about 3 hours to carry out a self-crosslinking reaction. Subsequently, the self-crosslinked polymer was crushed and classified to prepare a polymer in the form of granules with a size of about 150 μm to 850 μm.

[0178] Example 2.

[0179] A polymer in the form of granules was prepared in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 6.5.

[0180] Comparative Example 1.

[0181] A polymer in the form of granules was prepared in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 4.5.

[0182] Comparative Example 2.

[0183] A polymer in the form of granules was prepared in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 5.0.

[0184] Comparative Example 3.

[0185] A polymer in the form of granules was prepared in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 5.5.

[0186] Comparative Example 4.

[0187] A polymer in the form of granules was prepared in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 7.0.

[0188] Comparative Example 5.

[0189] A polymer in the form of granules was prepared in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 8.0 by using 0.5 N NaOH aqueous solution instead of 0.5 N HCl aqueous solution.

[0190] Comparative Example 6.

[0191] A polymer in the form of granules was prepared in the same manner as in Comparative Example 5, except that the pH of the mixture was adjusted to about 9.0.

[0192] The CRC evaluation results of the polymers of the above examples and comparative examples were summarized and described in Table 1 below.

[0193] [Table 1]

[0194] CRC (g / g) Example 1 34.0 Example 2 43.7 Comparative Example 1 5.9 Comparative Example 2 11.6 Comparative Example 3 23.3 Comparative Example 4 23.3 Comparative Example 5 19.2 Comparative Example 6 6.4

[0195] As can be seen from the results in Table 1, if the pH is too low or too high during the self-crosslinking process, a polymer with the desired absorption capacity cannot be obtained. It was determined that if the self-crosslinking reaction promoted under acidic conditions occurs too fast or too slow according to the pH, such a result is deterioration of the absorption capacity or leakage caused by the polymer solution during the absorption process.

[0196] Example 3.

[0197] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but the acidic polysaccharide was prepared such that the degree of substitution was about 0.4. The degree of substitution can be adjusted by regulating the amount of SMCA (sodium chloroacetate) applied during the preparation process. Generally, about 90% by weight of the applied SMCA reacts with starch to introduce carboxyl groups, and taking this into account, if the amount of applied SMCA is changed to about 30 g and thus the introduction amount of the NaOH aqueous solution (40% by weight) is changed to about 25 g, an acidic polysaccharide with a degree of substitution of about 0.4 can be produced.

[0198] Figure 2 For the 1 1H NMR results of the above-prepared acidic polysaccharide, and the degree of substitution obtained in the same manner as in Preparation Example 1 was about 0.4. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0199] Example 4.

[0200] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but a self-acidic polysaccharide with a degree of substitution of about 0.5 was obtained by regulating the amount of SMCA (sodium chloroacetate) to about 37 g and thus changing the introduction amount of the NaOH aqueous solution (40% by weight) to about 30.5 g. Figure 3 For the 1 1H NMR results of this acidic polysaccharide. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0201] Example 5.

[0202] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but a self-acidic polysaccharide with a degree of substitution of about 0.7 was obtained by regulating the amount of SMCA (sodium chloroacetate) to about 52 g and thus changing the introduction amount of the NaOH aqueous solution (40% by weight) to about 43 g. Figure 4 For the 1 1H NMR results of this acidic polysaccharide. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0203] Example 6.

[0204] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but by adjusting the amount of SMCA (sodium chloroacetate) to about 58 g, and accordingly changing the introduced amount of the NaOH aqueous solution (40 wt%) to about 49 g to obtain an acidic polysaccharide with a degree of substitution of about 0.8. Figure 5 For the 1 1H NMR results of this acidic polysaccharide. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0205] Example 7.

[0206] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but by adjusting the amount of SMCA (sodium chloroacetate) to about 65 g, and accordingly changing the introduced amount of the NaOH aqueous solution (40 wt%) to about 55 g to obtain an acidic polysaccharide with a degree of substitution of about 0.9. Figure 6 For the 1 1H NMR results of this acidic polysaccharide. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0207] Example 8.

[0208] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but by adjusting the amount of SMCA (sodium chloroacetate) to about 72 g, and accordingly changing the introduced amount of the NaOH aqueous solution (40 wt%) to about 61 g to obtain an acidic polysaccharide with a degree of substitution of about 1.0. Figure 7 For the 1 1H NMR results of this acidic polysaccharide. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0209] Example 9.

[0210] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but by adjusting the amount of SMCA (sodium chloroacetate) to about 99 g, and accordingly changing the introduced amount of the NaOH aqueous solution (40 wt%) to about 83 g to obtain an acidic polysaccharide with a degree of substitution of about 1.2. Figure 8 For the 1 1H NMR results of this acidic polysaccharide. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0211] Example 10.

[0212] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but by introducing an excess amount (about 120 g or more) of SMCA (sodium monochloroacetate), and thus changing the introduction amount of the aqueous NaOH solution (40 wt%) to about 100 g to obtain a self-acidic polysaccharide with a degree of substitution of about 1.4 or so. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0213] Example 11.

[0214] The process of preparing the acidic polysaccharide in Example 10 was repeated twice to obtain a self-acidic polysaccharide with a degree of substitution of about 1.6 or so. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0215] Comparative Example 7.

[0216] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but by adjusting the amount of SMCA (sodium monochloroacetate) to about 22 g or so to obtain a self-acidic polysaccharide with a degree of substitution of about 0.3 or so. Figure 9 This is the 1 1H NMR result of the acidic polysaccharide. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0217] Comparative Example 8.

[0218] The process of preparing the acidic polysaccharide in Example 10 was repeated four times to obtain a self-acidic polysaccharide with a degree of substitution of about 2.1 or so. Figure 10 This is the 1 1H NMR result of the acidic polysaccharide. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0219] Comparative Example 9.

[0220] The process of preparing the acidic polysaccharide in Example 10 was repeated 5 times or more to obtain a self-acidic polysaccharide with a degree of substitution of about 2.5 or so. Figure 11 This is the 1 1H NMR result of the acidic polysaccharide. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0221] Comparative Example 10.

[0222] A crosslinked polymer was obtained in the same manner as in Comparative Example 9, except that EG (ethylene glycol) was added to the mixture in an amount of about 0.3 wt% during the self-crosslinking reaction process. In this case, EG acts as an internal crosslinking agent, and thus the obtained polymer is not a self-crosslinked polymer.

[0223] Comparative Example 11

[0224] The crosslinked polymer was obtained in the same manner as in Comparative Example 9, except that EG (ethylene glycol) was added to the mixture in an amount of about 0.5% by weight during the reaction for self-crosslinking. In this case, EG acts as an internal crosslinking agent, and thus the obtained polymer is not a self-crosslinked polymer.

[0225] The CRC evaluation results of the polymers of the above Examples and Comparative Examples are summarized and described in Table 2 below.

[0226] [Table 2]

[0227] CRC (g / g) Example 3 35.7 Example 4 38.4 Example 5 45.8 Example 6 46.1 Example 7 43.4 Example 8 42.1 Example 9 40.8 Example 10 38.2 Example 11 34.5 Comparative Example 7 28.2 Comparative Example 8 19.2 Comparative Example 9 10.8 Comparative Example 10 24.4 Comparative Example 11 24.8

[0228] From the results in Table 2, it can be known that if the amount of carboxyl groups required for self-crosslinking increases, an overly dense crosslinked structure is achieved and at the same time the ratio of polar functional groups decreases, resulting in a decrease in the absorption capacity. In addition, it can be known that if the amount of carboxyl groups is too small, crosslinking cannot be fully achieved, and thus the absorption capacity also decreases. In the case of Comparative Example 9 where the degree of substitution was not appropriately adjusted, even when an internal crosslinking agent (EG) was added, the desired absorption capacity could not be obtained.

[0229] Example 12

[0230] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but using starch having a molecular weight of about 3.64×10 5 g / mol or so and a weight ratio of amylopectin (AP) to amylose (AM) of about 79:21 or so as the starch, and preparing the acidic polysaccharide such that it can have a degree of substitution of about 0.7 or so. The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0231] Example 13

[0232] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but using starch having a molecular weight of about 8.72×10 6 g / mol or so and a weight ratio of amylopectin (AP) to amylose (AM) of about 79:21 or so as the starch, and preparing the acidic polysaccharide such that it can have a degree of substitution of about 0.7 or so.

[0233] The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0234] Example 14

[0235] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, except that starch having a molecular weight of about 3.29×10 5 g / mol and a weight ratio of amylopectin (AP) to amylose (AM) of about 79:21 was used as the starch, and the acidic polysaccharide was prepared to have a degree of substitution of about 0.7.

[0236] The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0237] Example 15.

[0238] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, except that starch having a molecular weight of about 5.20×10 7 g / mol and a weight ratio of amylopectin (AP) to amylose (AM) of about 79:21 was used as the starch, and the acidic polysaccharide was prepared to have a degree of substitution of about 0.7.

[0239] The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0240] The CRC evaluation results of the polymers of the above examples are summarized and described in Table 3 below.

[0241] [Table 3]

[0242] CRC (g / g) Example 12 33.5 Example 13 38.8 Example 14 32.7 Example 15 42.1

[0243] Example 16.

[0244] An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, except that the weight ratio of amylopectin (AP) to amylose (AM) was adjusted to about 72:28. The molecular weight of the thus adjusted starch was about 1×10 7 g / mol, and the degree of substitution of the acidic polysaccharide was about 0.7.

[0245] The ratio of amylose to amylopectin in starch can be adjusted using n-butanol in the following manner. First, about 10 g of starch, 10 mL of ethanol, and about 300 mL of distilled water are mixed and stirred at about 90 °C until the mixture becomes transparent. Subsequently, 200 mL of a mixture of n-butanol and isoamyl alcohol with a volume ratio of 3:1 (n-butanol:isoamyl alcohol) is introduced into the transparent mixture, and the mixture is further heated for 20 to 30 minutes until the mixture becomes transparent (about 90 °C). Subsequently, after cooling it to room temperature (about 25 °C), it is stored at about 4 °C for about 24 hours, then centrifuged (3000 xg, 20 minutes), then the separated product is washed with ethanol, and then dried to obtain starch. Since amylose selectively forms a precipitate with n-butanol, the starch obtained by the above process has an increased amylose content compared to existing starch. The above process can be repeated until the desired amylose content is obtained.

[0246] The acidic polysaccharide was self-crosslinked in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0247] Comparative Example 12.

[0248] An acidic polysaccharide and a self-crosslinked polymer were respectively prepared as in Example 16, except that starch (waxy corn starch) with a weight ratio of amylopectin (AP) to amylose (AM) of about 96:4 was used.

[0249] Comparative Example 13.

[0250] An acidic polysaccharide and a self-crosslinked polymer were respectively prepared as in Example 16, except that the weight ratio of amylopectin (AP) to amylose (AM) was adjusted to about 61:39.

[0251] Comparative Example 14.

[0252] An acidic polysaccharide and a self-crosslinked polymer were respectively prepared as in Example 16, except that the weight ratio of amylopectin (AP) to amylose (AM) was adjusted to about 48:52.

[0253] Comparative Example 15.

[0254] An acidic polysaccharide and a self-crosslinked polymer were respectively prepared as in Example 16, except that the weight ratio of amylopectin (AP) to amylose (AM) was adjusted to about 40:60.

[0255] The CRC evaluation results of the polymers are summarized and described in Table 4 below.

[0256] [Table 4]

[0257] CRC (g / g) Example 16 35.8 Comparative Example 12 14.6 Comparative Example 13 20.2 Comparative Example 14 16.6 Comparative Example 15 15.7

Claims

1. A polymer comprising a self-crosslinked polysaccharide component, and wherein the centrifugal retention capacity of the polymer according to EDANA (European Disposables and Nonwovens Association) method WSP 241.3 is 30 g / g or greater.

2. The polymer according to claim 1, wherein the polysaccharide component is starch.

3. The polymer according to claim 1, comprising the self-crosslinked polysaccharide component in an amount of 80% by weight or more.

4. The polymer according to claim 1, wherein the polysaccharide component is an acidic polysaccharide component.

5. The polymer according to claim 1, wherein in the following Equation 1, F is 2.00 or greater: [Equation 1] F = AP × DS × Log(Mw) Among them, AP is the ratio of amylopectin in the polysaccharide component, DS is the degree of substitution of the polysaccharide component, and Mw is the molecular weight of the polysaccharide component.

6. The polymer according to claim 5, wherein AP in Equation 1 is in the range of 0.7 to 0.

9.

7. The polymer according to claim 5, wherein DS in Equation 1 is in the range of 0.4 to 2.

0.

8. The polymer according to claim 5, wherein Mw in Equation 1 is 10,000,000 or greater.

9. The polymer material according to claim 1, wherein the self-crosslinked polysaccharide component comprises a polymer chain containing monosaccharide units linked by glycosidic bonds, and a crosslinking bond of Formula 1 below that links the polymer chains: [Formula 1] Among them, L1 is an alkylene group, an alkylidene group or a bond of Formula 2 below, and L2 is represented by a single bond or -(CH2)-O-: [Formula 2] 10. The polymer material according to claim 9, wherein the monosaccharide unit has a ring structure containing carbon atoms and oxygen atoms as ring-forming atoms, and the bond of Formula 1 is directly connected to the carbon atom of the ring structure or is connected via a methylene group.

11. The polymer material according to claim 1, wherein the polysaccharide component comprises a unit represented by Formula 3 below: [Formula 3] Among them, R1 is a hydroxyl group, an amino group, -L5-C(=O)-OH, -L5-C(=O)-O - , or a functional group of Formula 4 below, R3 is a hydroxyl group, -L5-C(=O)-OH, -L5-C(=O)-O - , or a functional group of Formula 4 below, and one of L3 and L4 is a single bond and the other is CHR2, where R2 is a hydroxyl group, -L5-C(=O)-OH, -L5-C(=O)-O - , or a functional group of Formula 4 below, and L5 is an alkylene group or an alkylidene group, provided that any one of R1 to R3 is an oxygen atom of the bond of Formula 1 above (except for the oxygen atom present in the carbonyl group): [Formula 4] wherein, M1 is hydrogen or a metal, and when M1 is a metal, the above O-M1 bond is an ionic bond.

12. A method for producing the polymer according to any one of claims 1 to 11, comprising the step of self-crosslinking an acidic polysaccharide component under conditions where the pH is 6 or greater and less than 7.

13. The method for producing a polymer according to claim 12, wherein F in the following Equation 1 of the acidic polysaccharide component is 2.00 or greater: [Equation 1] F = AP × DS × Log(Mw) Among them, AP is the ratio of amylopectin in the polysaccharide component, DS is the degree of substitution of the polysaccharide component, and Mw is the molecular weight of the polysaccharide component.

14. An absorbent material comprising the polymer according to any one of claims 1 to 11.

15. A sanitary product comprising the polymer according to any one of claims 1 to 11.

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