polymer

Abstract

This specification discloses a polymer. The polymer may be an absorbable polymer used to form a so-called SAP. By adjusting the materials and conditions used in the crosslinking process to form the SAP, such a polymer can be formed without using a so-called crosslinking agent or with a minimal amount of crosslinking agent, thereby exhibiting excellent absorption capacity. The polymer is formed by crosslinking a biodegradable material without using a crosslinking agent or with a minimal amount of crosslinking agent, thereby maximizing the biodegradability of the material. This specification further discloses uses of the polymer.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0183662, dated December 23, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

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

[0003] Hydrogel Polymers or Hydrogels are generally defined as cross-linked hydrophilic polymers.

[0004] Such polymers may be used as materials known as SAPs (Super Absorbent Polymers). SAPs are materials that can absorb tens to thousands of times their own weight in water. SAPs are used in a variety of applications, including hygiene products such as sanitary napkins and diapers, medical supplies, daily necessities, agricultural materials, gardening materials, transportation materials, civil engineering and construction materials, materials related to electrical and electronic equipment, and water treatment agents.

[0005] The most widely used hydrogel polymers used as SAPs are vinyl-based materials such as cross-linked polyacrylic acid.

[0006] Although such materials are relatively inexpensive and have excellent water absorption capabilities, they remain semi-permanently even after disposal, causing various problems.

[0007] To solve this problem, there have been various attempts to produce SAP from so-called biodegradable materials.

[0008] However, currently known materials are unable to form SAPs with well-balanced physical properties. For example, the most typical physical property required for SAPs is absorbency, but currently known biodegradable SAPs do not sufficiently secure at least one of absorbency and biodegradability, or in some cases, do not secure both properties at an appropriate level.

[0009] For example, to use a biodegradable material as an SAP, the biodegradable material must be crosslinked to an appropriate level. Materials typically used as crosslinkers have no or reduced biodegradability, so crosslinking must be performed without using a crosslinker or with a minimal amount of crosslinker. However, biodegradable materials have no or reduced crosslinking sites, and even if they have some crosslinking sites, the degree of crosslinking can be reduced depending on the structure, which can be problematic. Summary of the Invention [Problem to be solved by the invention]

[0010] This specification discloses a polymer. It aims to provide a polymer that effectively exhibits excellent absorption capacity without using a so-called crosslinking agent or using only a minimal amount of crosslinking agent by adjusting the materials and conditions used in the crosslinking process to form SAP. This specification also aims to disclose the ability to maximize the biodegradability of a biodegradable material by crosslinking the material without using SAP as a crosslinking agent or using only a minimal amount of SAP. This specification further discloses uses of the polymer. [Means for solving the problem]

[0011] In the present specification, when a physical property is affected by the temperature at which it is measured, the physical property is measured at room temperature unless otherwise specified.

[0012] As used herein, the term "room temperature" refers to a natural temperature that is neither heated nor cooled, and means, for example, any temperature within the range of 10°C to 30°C, or a temperature of about 23°C, about 25°C, or about 27°C. Unless otherwise specified, the unit of temperature used herein is Celsius (°C).

[0013] In the present specification, when the measurement pressure affects a physical property, the physical property is measured at normal pressure unless otherwise specified.

[0014] In this specification, the term "normal pressure" refers to the natural pressure that is neither pressurized nor reduced, and generally refers to any pressure within the range of approximately 730 mmHg to 790 mmHg.

[0015] In the present specification, when a physical property is affected by the humidity at which it is measured, the physical property is measured at room temperature and pressure without any special adjustment of humidity, unless otherwise specified.

[0016] This specification discloses a polymer.

[0017] The polymer may be a so-called cross-linked polymer or a polymer before being cross-linked. When the polymer is a cross-linked polymer, the polymer may be a hydrogel polymer or a hydrogel.

[0018] The polymer may be an absorbent polymer.

[0019] Such absorbent polymers can exhibit at least one of a moisture content, a centrifuge retention capacity (CRC), and an absorbent capacity under pressure (AUP) within the ranges described herein.

[0020] For example, the polymer's centrifuge retention capacity (CRC) according to EDANA (European Disposables and Nonwovens Association) method WSP 241.3 may have a lower limit of 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 an upper limit of 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 CRC may be greater than or equal to any of the lower limits, or greater than or equal to any of the lower limits but less than or equal to any of the upper limits. The centrifuge retention capacity may be evaluated by the method described in "1. Evaluation of Centrifuge Retention Capacity (CRC)" in the Examples section of this specification.

[0021] The lower limit of the water content of the polymer may be about 40 wt%, 45 wt%, 50 wt%, or 55 wt%, and the upper limit may be about 70 wt%, 65 wt%, or 60 wt%. The water content may be greater than or exceeding any of the lower limits, or greater than or exceeding any of the lower limits but less than or equal to any of the upper limits. The water content is the water content of the polymer relative to the total weight of the polymer being measured and can be calculated based on the weight of the polymer containing water and the weight of the dried polymer. For example, the water content can be calculated based on the weight loss due to evaporation of water from the polymer during the drying process by increasing the temperature of the crumb-like polymer using infrared heating. The drying process for measuring the water content may include heating the polymer from room temperature to about 50°C and then maintaining the temperature at 50°C while vacuum drying for about 6 hours.

[0022] The polymer's absorbent capacity under pressure (AUP) at 0.7 psi according to EDANA (European Disposables and Nonwovens Association) method WSP242.3 may have a lower limit of about 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 an upper limit of about 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 AUP may be greater than or equal to any of the lower limits, or greater than or equal to any of the lower limits but less than or equal to any of the upper limits.

[0023] The polymer may be defined as an absorbent polymer if it exhibits at least one of the properties of moisture content, centrifuge water retention, and absorbency under pressure. The polymer may exhibit any one, two or more, or all of the properties of moisture content, centrifuge water retention, and absorbency under pressure.

[0024] The polymer may be a biodegradable polymer.

[0025] For example, the lower limit of the biodegradability of the polymer may be about 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94%, 96%, 98%, or 99%, and the upper limit may be about 100%, 98%, 96%, 94%, 92%, 90%, 88%, 86%, 84%, 82%, 80%, 78%, or 76%. The biodegradability may be greater than or exceeding any of the lower limits, or greater than or exceeding any of the lower limits but less than or equal to any of the upper limits. The polymer may exhibit biodegradability before or after crosslinking.

[0026] The term "polymer" refers to a high molecular weight substance formed by covalently linking two or more monomers (e.g., monomers). The polymer refers to a substance having a structure in which two or more monomers are covalently linked and exhibiting a molecular weight above a certain level. The range of the molecular weight will be described later.

[0027] The polymer may be or include a polysaccharide moiety.

[0028] The term "polysaccharide component" refers to a polysaccharide or a mixture of polysaccharides. In the case of a mixture of polysaccharides, the mixture may be a mixture of one type of polysaccharide or a mixture of two or more types of polysaccharides. In this context, two or more types of polysaccharides refer to different types of polysaccharides, and may include polysaccharides of the same type but with different physical properties such as molecular weight. The polysaccharide component contains only polysaccharides.

[0029] The term "polysaccharide" has its meaning as known in the art. Generally, a polysaccharide refers to a polymeric molecule in which two or more monomers are covalently linked. The covalent bonds linking the monomers are usually glycosidic bonds.

[0030] Representative polysaccharides include starch, glycogen, cellulose, chitin, and chitosan.

[0031] The monomers forming the polysaccharide may be composed of carbon, hydrogen, and oxygen, or may be biomolecules composed of carbon, hydrogen, oxygen, and nitrogen. The term "biomolecule" is to be interpreted as having the meaning commonly used in the art. Examples of biomolecules generally known in the art include monosaccharides such as glucose, galactose, fructose, and xylose; disaccharides such as sucrose, lactose, maltose, and trehalose; polyols such as sorbitol and mannitol; oligosaccharides such as maltodextrin, dextrin, raffinose, stachyose, and fructooligosaccharides; and / or amino sugars such as glucosamine and N-acetylglucosamine. However, the types of biomolecules of the present invention are not limited to these.

[0032] The lower limit of the content of the polysaccharide or polysaccharide component in the polymer may 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 may be about 100 wt%, 98 wt%, 96 wt%, 94 wt%, 92 wt%, or 90 wt%. The percentage may be greater than or equal to any of the lower limits, less than or equal to any of the upper limits, or greater than or equal to any of the lower limits but less than or equal to any of the upper limits.

[0033] Although there is no particular limitation on the proportion of the polysaccharide component in the polymer, the higher the proportion, the greater the biodegradability of the polymer. However, in the case of conventional absorbent materials that use polysaccharide components, if the proportion of the polysaccharide component is increased too much in consideration of biodegradability, there is a problem that the absorbency decreases. However, in the polymer, the desired absorbency can be stably achieved while maintaining the proportion of the polysaccharide component at a high level.

[0034] If the polymer (e.g., the polysaccharide or polysaccharide component) is crosslinked and has absorbent properties, the polymer may also be referred to as a hydrogel polymer or hydrogel. In one example, the polymer may be in the form of a powder formed by a grinding process or the like.

[0035] The powdered polymer may be subjected to additional processes such as surface cross-linking.

[0036] The polymer, polysaccharide, or polysaccharide component may be in a crosslinked state. The crosslinking refers to a state in which two or more molecules of a polymer, polysaccharide, or polysaccharide component are linked by one or more chemical bonds. Typically, crosslinks are formed by a compound called a crosslinking agent. Such a crosslinking agent may have two or more functional groups that can react with the polymer, polysaccharide, or polysaccharide component, and a crosslinked structure may be formed by such functional groups.

[0037] In one example, the crosslinking of the polymer may be performed without using a crosslinking agent or with a minimal amount of crosslinking agent. Most crosslinking agents used to form SAPs known to date are substances with little or no biodegradability, so even if a biodegradable polysaccharide or polysaccharide component is used as the polymer, the biodegradability is often not fully realized after crosslinking. Therefore, by performing crosslinking without using a crosslinking agent or with a minimal amount of crosslinking agent, a polymer can be obtained that exhibits the desired absorption capacity and realizes the biodegradability of the material.

[0038] As mentioned herein, crosslinking that is carried out without the use of crosslinking agents or with minimal amounts of crosslinking agents is also referred to as self-crosslinking.

[0039] In one example, the polymer may include the self-crosslinked polysaccharide or self-crosslinked polysaccharide component.

[0040] For example, the percentage of the self-crosslinked polysaccharide or self-crosslinked polysaccharide component in the polymer, based on the total weight of the polymer, may be about 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99%, or 99.5% by weight, and the upper limit may be about 100%, 98%, 96%, 94%, 92%, or 90% by weight. The percentage may be greater than or equal to any of the lower limits, or greater than or equal to any of the lower limits but less than or equal to any of the upper limits.

[0041] The upper limit of the proportion of crosslinker in the self-crosslinked polymer, self-crosslinked polysaccharide, or self-crosslinked polysaccharide component, based on the total weight of the self-crosslinked polymer, self-crosslinked polysaccharide, or self-crosslinked polysaccharide component, may 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 may be about 0 wt%. The proportion of crosslinker may be within a range equal to or less than any of the above upper limits, or within a range equal to or greater than any of the above lower limits but equal to or less than any of the above upper limits. The cross-linking agent as used herein refers to a substance that forms a chemical bond that connects the polymer, polysaccharide, or polysaccharide component, but is not a polymer, polysaccharide, or polysaccharide component.

[0042] In this way, crosslinking can maximize the biodegradability of the material itself while maintaining absorbency when performed without using a crosslinking agent or with a minimal amount of crosslinking agent. With commonly known biodegradable polysaccharides or polysaccharide components, it is difficult to obtain polymers with desired properties (e.g., absorbency) due to reduced crosslinking efficiency. This specification discloses specific types of polysaccharides or polysaccharide components and crosslinking methods that can effectively self-crosslink without using a crosslinking agent. Such polysaccharides or polysaccharide components are in a self-crosslinked state and have excellent physical properties (e.g., absorbency) while retaining excellent biodegradability.

[0043] The self-crosslinking of the polysaccharide component may be carried out using a so-called acidic polysaccharide component. The acidic polysaccharide component is a polysaccharide component having acidic groups. Examples of the acidic groups include carboxylic groups, phosphate groups, phosphite groups, and / or sulfuric ester groups or salts thereof.

[0044] For effective self-crosslinking, the acidic polysaccharide component may be adjusted. For example, the polysaccharide component may have F in the following formula 1 at a certain level or higher. F is the value for the polysaccharide component before self-crosslinking.

[0045] [Formula 1] F = AP × DS × Log(Mw)

[0046] In Equation 1, AP is the proportion 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.

[0047] In Equation 1, AP is the proportion of amylopectin in the polysaccharide component and is measured using the method described in "3. Measurement of Amylopectin and Amylose Content" in the Examples section of this specification. The AP is calculated as AP / (Am+AP) when the sum of the weight of amylose (Am) and the weight of amylopectin (AP) in the polysaccharide component (Am+AP) is converted to 100. As is well known, polysaccharide components are often primarily composed of amylose and amylopectin. Amylose and amylopectin are composed of glucose molecules linked by glycosidic bonds. Amylose has a linear chain structure, while amylopectin has relatively short and highly branched chains. Furthermore, amylose crystallizes more easily than amylopectin, and amylopectin has a higher solubility in water than amylose. Therefore, the ratio of amylose to amylopectin in the polysaccharide component may 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 steric structure that affects the steric hindrance of the polysaccharide component, and the self-crosslinking efficiency can be affected by this steric structure.

[0048] The degree of substitution DS in Equation 1 is a value indicating the degree to which the hydroxyl groups present in each monomer contained in the polysaccharide component have been substituted with acidic groups, and is an average value for each monomer present in the polysaccharide component. For example, if the monomer is a glucose unit, the unit before modification has three hydroxyl groups. Therefore, if all of the hydroxyl groups are substituted with acidic groups, the degree of substitution for the unit is 3. The degree of substitution of a polysaccharide component is an average value of the degree of substitution of each monomer present in the polysaccharide component. For example, in a polysaccharide component containing five glucose units, if the degrees of substitution for each unit are 1, 0, 2, 3, and 1, the degree of substitution of the polysaccharide is an average value of 1.4. Such degrees of substitution are 1 This can be confirmed through H NMR analysis. 1Through H NMR analysis, the hydroxyl groups present in the polysaccharide and the substituted functional groups can be quantified, so the degree of substitution can be confirmed. 1 The degree of substitution can be calculated based on the results of 1 H NMR analysis.

[0049] The aforementioned 1 The method for performing H NMR analysis is described in "4. NMR analysis" in the Examples section of this specification, and an example of determining the degree of substitution DS based on the results is described in Production Example 1 in the Examples section.

[0050] In Equation 1, Mw is the molecular weight of the polysaccharide component, and the molecular weight related to bulkiness is also related to the three-dimensional structure associated with self-crosslinking. The molecular weight is evaluated by the method described in "2. Measurement of Molecular Weight of Polysaccharide Component" in the Examples section of this specification.

[0051] By adjusting F in Formula 1, which is determined by such factors, a polysaccharide component that is effectively self-crosslinked can be obtained.

[0052] In Formula 1, the lower limit of F may be about 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 the upper limit may be about 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 may be greater than or equal to any of the lower limits, or greater than or equal to any of the lower limits but less than or equal to any of the upper limits.

[0053] In Formula 1, when F is within the above range, the polysaccharide component exhibits properties that allow it to exhibit excellent absorption capacity, has an amount of substituents that allows for effective self-crosslinking, and exhibits a three-dimensional structure that is suitable for crosslinking. Furthermore, such polysaccharide components can exhibit excellent absorption capacity after crosslinking.

[0054] The ranges of Mw, DS and AP for determining F in Equation 1 may be further adjusted to appropriate levels.

[0055] For example, the lower limit of Mw in Formula 1 may be about 50,000, 100,000, 150,000, 200,000, 250,000, 300,000, 500,000, 1 million, 5 million, 10 million, 15 million, 20 million, 25 million, 30 million, 35 million, 40 million, 45 million, 50 million, 55 million, 60 million, or 64 million, and the upper limit may be about 1,000,000, 950,000, 900,000, or 850,000. million, 800,000 million, 750,000 million, 700,000 million, 650,000 million, 600,000 million, 550,000 million, 500,000 million, 450,000 million, 400,000 million, 350,000 million, 3 00,000 million, 250,000 million, 200,000 million, 150,000 million, 100,000 million, 95,000 million, 90,000 million, 85,000 million, 80,000 million, 75,000 million, 70,000 million, 65 ,0 million, 60,000 million, 55,000 million, 50,000 million, 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, 5 million, 9, 0 million, 85 million, 80 million, 75 million, 70 million, 65 million, 60 million, 55 million, 50 million, 45 million, 40 million, 35 million, 3 The Mw may be about 10 million, 25 million, 20 million, 15 million, 10 million, 9.5 million, 9 million, 8.5 million, 8 million, 7.5 million, 7 million, 6.5 million, 6 million, 5.5 million, 5 million, 4.5 million, 4 million, 3.5 million, 3 million, 2.5 million, 2 million, 1.5 million, 1 million, 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 350,000. The Mw may be greater than or exceeding any one of the lower limits mentioned above, or greater than or exceeding any one of the lower limits mentioned above but less than or equal to any one of the upper limits mentioned above.

[0056] In Formula 1, the lower limit of DS may 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 the upper limit may 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. The DS may be greater than or equal to any of the lower limits mentioned above, but less than or equal to any of the upper limits mentioned above.

[0057] In Formula 1, the lower limit of AP may be about 0.6, 0.65, 0.7, 0.72, 0.74, 0.76, or 0.78, and the upper limit may be about 0.95, 0.9, 0.85, 0.8, or 0.75. The AP may be greater than or exceeding any of the lower limits, but less than or equal to any of the upper limits.

[0058] The self-crosslinking of the polysaccharide component may be carried out using, for example, a polysaccharide component having a carboxyl group or a salt of a carboxyl group as an acidic group among the above-mentioned acidic polysaccharide components. Since polysaccharides themselves contain hydroxyl groups, the self-crosslinking may be carried out by esterifying the hydroxyl group contained in any of the polysaccharide molecules with the carboxyl group or the salt of the carboxyl group contained in the acidic polysaccharide.

[0059] The type of polysaccharide component having a carboxyl group or a salt of a carboxyl group is not particularly limited. For example, the self-crosslinking may be performed using a polysaccharide that itself has a carboxyl group, such as carboxylmethyl cellulose (CMC), which is a wood-based polysaccharide, or a polysaccharide into which a carboxyl group or a salt thereof has been introduced through a process such as maleation or carboxyalkylation.

[0060] The self-crosslinked polysaccharide component may comprise polymeric chains comprising monosaccharide units linked by glycosidic bonds (i.e., crosslinked polysaccharide chains) and crosslinks connecting the polymeric chains.

[0061] In this case, the cross-linking bond may be linked to the monosaccharide unit.

[0062] The cross-linked bond may be a bond represented by the following formula 1.

[0063] [ka]

[0064] In Chemical Formula 1, L1 is an alkylene group, an alkylidene group, or a bond as shown in Chemical Formula 2 below, and L2 is a single bond or -(CH2)-O-.

[0065] [ka]

[0066] The oxygen atom shown on the left-most side of formula 1 may be directly attached to a monosaccharide unit of the polymer chain.

[0067] When L2 is a single bond in Chemical Formula 1, L2 does not exist. That is, when L2 is present in Chemical Formula 1, L2 is directly linked to a monosaccharide unit of the polymer chain, and when L2 is a single bond, the oxygen atom on the left side of L2 in Chemical Formula 1 may be directly linked to the monosaccharide unit.

[0068] In Chemical Formula 1, the alkylene group refers to a functional group in which two hydrogen atoms have been removed from an alkane and linked to another object, and in this case, the two hydrogen atoms have been removed from other carbon atoms of the alkane. Such an alkylene group may be an alkylene group having 2 to 20, 2 to 16, 2 to 12, 2 to 8, or 2 to 4 carbon atoms. Such an alkylene group may be linear, branched, or cyclic. Such an alkylene group may be optionally substituted with at least one substituent.

[0069] In Chemical Formula 1, the alkylidene group refers to a functional group in which two hydrogen atoms have been removed from an alkane and linked to another object, and in this case, the two hydrogen atoms have been removed from one carbon atom of the alkane. Such an alkylidene group may be an alkylidene group 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 group may be linear, branched, or cyclic. Such an alkylidene group may be optionally substituted with at least one substituent.

[0070] When the self-crosslinking of polysaccharides is carried out by polysaccharides that themselves have a carboxyl group or a salt thereof, such as CMC (carboxylmethyl cellulose), or polysaccharides that have a carboxyl group or a salt thereof introduced by carboxyalkylation, L1 in Chemical Formula 1 may generally be an alkylene group or an alkylidene group. When L1 in Chemical Formula 1 is a functional group represented by Chemical Formula 2, self-crosslinking is carried out by a carboxyl group or a salt thereof introduced by maleation, etc.

[0071] When L1 in Chemical Formula 1 is Chemical Formula 2, the carbon atom of the carbonyl group in Chemical Formula 2 is linked to the oxygen atom on the left side of L1 in Chemical Formula 1, and the carbon atom on the right side of the carbon-carbon double bond in Chemical Formula 2 is linked to the carbon atom of the carbonyl group on the right side of L1 in Chemical Formula 1.

[0072] There may be at least one bond of formula (1) in the self-crosslinked polysaccharide component.

[0073] The type of the monosaccharide unit is not particularly limited, and may be any monosaccharide unit that normally constitutes a polysaccharide, such as a glucose unit, a glucosamine unit, or an N-acetylglucosamine unit.

[0074] Such monosaccharide units typically contain a ring structure containing carbon and oxygen atoms. The ring structure of the monosaccharide unit is typically a six-membered ring structure (containing only five carbon atoms and one oxygen atom), but may be a ring structure with six or more members. When the ring structure is six or more members, the ring atoms may be carbon atoms or heteroatoms such as oxygen or nitrogen atoms.

[0075] In the case of a self-crosslinking structure, the bond of formula (1) may be directly connected to the carbon atom of the ring structure of the monosaccharide unit as described above, or may be connected via a methylene group (-CH2-).

[0076] At least one or all of the leftmost oxygen atom and the rightmost oxygen atom of Chemical Formula 1 (when L2 is a single bond, it means the oxygen atom connected to the right side of the carbonyl group, and when it is not a single bond, it means the oxygen atom of -(CH2)-O-) may be directly connected to a carbon atom of the ring structure or may be connected via a methylene group (-CH2-).

[0077] In the above, being linked via a methylene group (-CH2-) means that only the methylene group (-CH2-) is present between the leftmost oxygen atom of the formula 1 or the rightmost oxygen atom of the formula 1 (when L2 is not a single bond, the oxygen atom of -(CH2)-O-) and the carbon atom of the ring structure.

[0078] In this case, more specifically, the polysaccharide component may contain a unit represented by the following formula 3.

[0079] [ka]

[0080] In Chemical Formula 3, R1 is a hydroxy group, an amino group, -L5-C(=O)-OH, -L5-C(=O)-O - Or a functional group of the following formula 4, where R3 is a hydroxy group, -L5-C(=O)-OH, -L5-C(=O)-O - or a functional group of the following formula 4, wherein either L3 or L4 is a single bond and the other is CHR2, and R2 is a hydroxy group, -L5-C(=O)-OH, -L5-C(=O)-O - Or a functional group of the following formula 4, wherein L5 is an alkylene group or an alkylidene group, and any of R1 to R3 is an oxygen atom of the bond of formula 1 (excluding the oxygen atom present in the carbonyl group).

[0081] [ka]

[0082] In Chemical Formula 4, M1 is hydrogen or a metal, and when M1 is a metal, the O-M1 bond is an ionic bond.

[0083] The functional group -L5-C(=O)-OH or -L5-C(=O)-O- in Chemical Formula 3 may be, for example, a carboxyl group introduced by carboxyalkylation or a functional group obtained by ionizing the carboxyl group, and Chemical Formula 4 is a functional group introduced by maleation.

[0084] In Chemical Formula 3, the specific types of alkylene group and alkylidene group are the same as in Chemical Formula 1.

[0085] Such functional groups are introduced to participate in the self-crosslinking reaction described above to form crosslinks, but not all of the introduced functional groups may participate in the crosslinking reaction, and in such cases, some functional groups may remain.

[0086] In the above, when either L3 or L4 is a single bond, it means that either L3 or L4 is absent. For example, when L3 is absent, the carbon atoms connected to the left and right sides of L3 in Chemical formula 3 are directly connected, and when L4 is absent, the carbon atoms connected to the left and right sides of L4 in Chemical formula 3 are directly connected.

[0087] When either L3 or L4 is CHR2, it means that either L3 or L4 in Chemical Formula 3 is a carbon atom, and the carbon atom is substituted with a substituent R2.

[0088] In Chemical Formula 3, when any of R1 to R3 is an oxygen atom of the bond of Chemical Formula 1 (excluding the oxygen atom present in the carbonyl group), it means that any of R1 to R3 is an oxygen atom of the bond of Chemical Formula 1 linking the polysaccharides, and in this case, the oxygen atom means either the leftmost oxygen atom or the rightmost oxygen atom of Chemical Formula 1 (when L2 is a single bond, it means the oxygen atom linked to the right of the carbonyl group, and when it is not a single bond, it means the oxygen atom of -(CH2)-O-).

[0089] As described above, the self-crosslinking structure can be realized by esterifying acidic polysaccharides, particularly polysaccharides having a carboxyl group or its salt, with each other. In this self-crosslinking reaction, a polymer with well-balanced absorption properties can be obtained by adjusting the reaction conditions, particularly the pH, as described below.

[0090] As the acidic polysaccharide, a polysaccharide that itself has a carboxyl group or its salt, such as CMC (carboxylmethyl cellulose), or a polysaccharide into which a carboxyl group or its salt has been introduced through a process such as maleation or carboxyalkylation, can be used. However, a polysaccharide into which a carboxyl group or its salt has been introduced through a modification process may also be used to achieve the above-mentioned degree of substitution and for efficient self-crosslinking.

[0091] There are no particular limitations on the method for introducing a carboxyl group or its salt into a polysaccharide. For example, a so-called maleation process may be performed to introduce a functional group such as that shown in Chemical Formula 4. This process involves reacting a polysaccharide with an unsaturated dicarboxylic acid or its anhydride to substitute the hydroxyl group present in the monomer of the polymer with the functional group. Examples of the dicarboxylic acid or its anhydride include, but are not limited to, maleic acid or maleic anhydride, and salts of maleic acid may also be used. Methods for performing the maleation process are well known.

[0092] The carboxyalkylation process may be carried out by reacting the polysaccharide component with an alkanoic acid, a haloalkanoic acid, or a salt of the alkanoic acid or haloalkanoic acid. For example, the hydroxyl groups of the polysaccharide component may be protonated using an additive such as NaOH, and then the carboxyl group or its salt may be introduced into the polysaccharide component by reaction with the alkanoic acid.

[0093] As is well known, an alkanoic acid is an aliphatic acid derived from an alkane, and a haloalkanoic acid refers to an alkanoic acid in which at least one hydrogen atom has been substituted with a halogen atom (e.g., chlorine, fluorine, or bromine). In this specification, the alkanoic acid, haloalkanoic acid, salt of an alkanoic acid, and / or salt of a haloalkanoic acid applied in the carboxyalkylation step are also referred to as a treating agent.

[0094] The alkanoic acid or haloalkanoic acid used as the treatment agent may be, for example, 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, and acetic acid or chloroacetic acid may be typically used.

[0095] The salt of the haloalkanoic acid or alkanoic acid may be an alkali metal salt or alkaline earth metal salt of a haloalkanoic acid or alkanoic acid having the above carbon number.

[0096] Acidic groups (such as carboxyl groups) may be introduced into the polysaccharide by reacting the polysaccharide with the treating agent under appropriate conditions.

[0097] The step of introducing the acidic group may be carried out by a known method, and if necessary, an additional step may be carried out or the process conditions may be adjusted for efficient progress of the carboxyalkylation step.

[0098] For example, the process may be performed on a mixture in which the treatment agent and hydroxide are dispersed in a solvent. The solvent may be, for example, an aqueous solvent such as water. The water may be tap water, distilled water, deionized water, or purified water. The hydroxide may be ammonium hydroxide or a metal hydroxide, and the metal hydroxide may be, but is not limited to, sodium hydroxide, potassium hydroxide, or lithium hydroxide.

[0099] Such metal hydroxides can act as the additives that protonate the hydroxy groups of the polysaccharide components.

[0100] In the reaction with the mixture, for example, first, a gelatinization reaction of the polysaccharides is carried out in the mixture, and then a carboxyl group or the like is introduced by a treating agent.

[0101] In this process, the degree of substitution can be controlled by controlling the amount of treating agent in the mixture. In this reaction, approximately 90% by weight of the treating agent typically reacts with the polysaccharide component, introducing carboxyl groups or the like into the polysaccharide component. Therefore, a desired degree of substitution can be achieved by applying an appropriate level of treating agent to the polysaccharide component used, taking this into consideration. To achieve a certain level of substitution or higher, the preparation and reaction of the mixture may be repeated multiple times, and the proportion of the hydroxide added may also be controlled as needed.

[0102] For example, the lower limit of the hydroxide ratio in the mixture may be about 0.5, 0.6, or 0.7 equivalents, and the upper limit may be about 1.5, 1.15, 1.1, 1, 0.9, or 0.8 equivalents. The equivalents may be less than or equal to any of the upper limits, or greater than or equal to any of the lower limits but less than or equal to any of the upper limits. The equivalents can be calculated using the formula A / B, where A is the number of moles of hydroxide present in the mixture and B is calculated using the formula C / 162.14, where C is the weight (units: g) of polysaccharide in the mixture. 162.14 is the molar mass (g / mol) of an anhydroglucose unit. Typically, polysaccharides contain the anhydroglucose unit or its derivatives, or units with similar molar masses. Therefore, in the present invention, if the amount of polysaccharide used to calculate the equivalent weight is representatively applied to the above formula C / 162.14, the reaction can be carried out according to the intended purpose by defining the equivalent weight within the above range. Maintaining the amount of hydroxide used within the above range allows the substitution efficiency of carboxyl groups, etc., to be maintained within the desired range, while stably maintaining reaction efficiency and workability and suppressing unwanted side reactions.

[0103] The lower limit of the proportion of the treating agent in the mixture may be about 0.5, 0.6, or 0.7 equivalents, and the upper limit may be about 1.5, 1.15, 1.1, 1, 0.9, or 0.8 equivalents. The equivalent may be less than or equal to any of the upper limits, or greater than or equal to any of the lower limits but less than or equal to any of the upper limits. The equivalent may be calculated using the formula D / B, where D is the number of moles of the treating agent present in the mixture and B is the same as in the formula for calculating the hydroxide equivalent. Maintaining the amount of treating agent used within the above ranges allows for maintaining the substitution efficiency of carboxyl groups and the like within a desired range, while maintaining stable reaction efficiency and workability and suppressing unwanted side reactions.

[0104] The ratio (A / B) of the moles of the hydroxide (A) to the moles of the treating agent (D) in the mixture may have a lower limit of about 0.5, 0.6, 0.7, 0.8, 0.9, or 0.95, and an upper limit of about 1.5, 1.4, 1.3, 1.2, 1.1, or 1.05. The ratio may be equal to or less than any of the above upper limits, or may be equal to or greater than any of the above lower limits but less than any of the above upper limits. Maintaining the above ratio allows for the production of a stable self-crosslinkable polysaccharide while maintaining the substitution efficiency of carboxyl groups and the like within a desired range, thereby stably maintaining reaction efficiency and workability and suppressing unwanted side reactions.

[0105] In the reaction, the mixture may be present in a reactor in a predetermined ratio. For example, the lower limit of the volume ratio of the mixture in the reactor may be about 70%, 75%, 76%, or 77% based on the total volume of the reactor, and the upper limit may be about 95%, 94%, 93%, or 92%. The ratio may be less than or equal to any of the upper limits, or may be greater than or equal to any of the lower limits but less than or equal to any of the upper limits. Maintaining the ratio may stably maintain the torque in the reactor, maintain the substitution efficiency of carboxyl groups, etc., within a desired range, produce a stable self-crosslinkable polysaccharide component, stably maintain reaction efficiency and workability, and suppress unwanted side reactions.

[0106] The carboxyalkylation is carried out by maintaining the mixture at an appropriate temperature for a certain period of time to obtain the desired acidic polysaccharide. If necessary, an additional step such as stirring may be carried out during this process.

[0107] The present specification further discloses a method for preparing the polymer via the step of self-crosslinking an acidic polysaccharide component, such as the acidic polysaccharide component described above.

[0108] The acidic polysaccharide component may be any of the above-described components. After introducing acidic groups such as carboxyl groups into the polysaccharide component through the above-described reaction, a self-crosslinking process may be performed immediately. If necessary, the polysaccharide component may be recovered first and then the self-crosslinking process may be performed. The polysaccharide component may be recovered by dissolving the reaction product in water and precipitating it using an organic solvent such as alcohol, or by various other methods.

[0109] The acidic polysaccharide component may have the range of F in Formula 1, and values ​​of AP, DS, and Mw in Formula 1 described above.

[0110] The method for performing self-crosslinking is not particularly limited, but for efficient self-crosslinking, the acidic polysaccharide may be dispersed in a solvent and then maintained at a predetermined pH range.

[0111] In the above process, an aqueous solvent such as water may be used as the solvent. The water may be tap water, distilled water, deionized water, or purified water.

[0112] During self-crosslinking, it is appropriate to use substantially only the aqueous solvent (e.g., water) as the solvent. Therefore, the solvent used during self-crosslinking may be substantially free of other solvents other than the aqueous solvent (e.g., water). In this case, "substantially free of other solvents" means that the content of other solvents other than the aqueous solvent (e.g., water) in the solvent is approximately 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%, with the lower limit being approximately 0 wt%. The proportion may be within a range of less than or equal to any of the above upper limits, or may be greater than or equal to or exceeding any of the above lower limits while being less than or equal to any of the above upper limits.

[0113] The amount of the solvent used in the above process may be 5 to 15 times the weight of the polysaccharide used. The dissolution of the polysaccharide in the solvent may be carried out under normal temperature and pressure conditions, but is not limited thereto.

[0114] Self-crosslinking may be achieved by dissolving the polysaccharide in the solvent and maintaining the pH at a certain level. If necessary, additional steps may be carried out to promote self-crosslinking, such as a stirring step.

[0115] The lower limit of the pH maintained during the process may be about 6, 6.1, 6.2, 6.3, 6.4, or 6.5, and the upper limit may be about 7, 6.9, 6.8, 6.7, 6.6, 6.5, 6.4, 6.3, 6.2, 6.1, or 6. The pH may be within a range of not more than or less than any of the above upper limits, or not less than or equal to any of the above lower limits, or not less than or equal to any of the above upper limits while not more than or equal to any of the above lower limits. By maintaining such a pH range, the desired self-crosslinking can be effectively achieved.

[0116] 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 performed under that condition. If the desired pH is not achieved, the pH can be adjusted by adding an appropriate acid or base in consideration of the target pH. In this case, the hydroxide used in the carboxyalkylation can be used as the base, and hydrochloric acid, sulfuric acid, etc. can be used as the acid, but the methods are not limited thereto.

[0117] A catalyst may be added during the reaction process, if necessary. For example, an ester catalyst that promotes the reaction between a carboxyl group and a hydroxy group may be added. Examples of such catalysts include, but are not limited to, 4-methylaminopyridine, magnesium acetate, tetra-n-butyl titanate, lead acetate, sodium acetate, potassium acetate, antimony trioxide, and / or N-methylimidazole. The catalyst may be added in a catalytic amount, for example, in a ratio of 0.1 to 5 moles per mole of polysaccharide used in the reaction. The lower limit of the catalyst use ratio may be about 0.1 moles, 0.5 moles, 1 mole, or 2 moles, and the upper limit may be about 5 moles, 4.5 moles, 4 moles, or 3.5 moles. The ratio may be less than or equal to any of the above upper limits, or may be greater than or equal to, but less than, any of the above lower limits.

[0118] The reaction may be carried out in the presence of a heat stabilizer, if necessary. Suitable heat stabilizers include organic or inorganic phosphorus compounds such as phosphoric acid, organic esters of phosphoric acid, phosphorous acid, or organic esters of phosphorous acid, such as phosphoric acid, alkyl phosphates, or aryl phosphates, which are commercially known as heat stabilizers.

[0119] The reaction may be carried out in the presence of additives such as thickeners, plasticizers, storage stabilizers and / or antioxidants, if necessary.

[0120] The crosslinking reaction may be carried out at a predetermined temperature. For example, the lower limit of the temperature at which the reaction is carried out may 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 may 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 may be equal to or higher than any of the lower limits listed above, but may be equal to or lower than any of the upper limits listed above. The reaction temperature may be controlled by, for example, supplying hot air, irradiating with infrared rays, irradiating with ultrashort waves, or irradiating with ultraviolet rays.

[0121] The reaction time is not particularly limited, and for example, the lower limit of the reaction time may be about 30, 60, 90, 120, 150, or 180 minutes, and the upper limit may be about 500, 480, 460, 440, 420, 400, 380, 360, 340, 320, 300, 280, 260, 240, 220, 200, or 180 minutes. The reaction time may be greater than or exceeding any of the lower limits mentioned above, but less than or equal to any of the upper limits mentioned above.

[0122] The method results in the desired self-crosslinked polysaccharide component.

[0123] After such a cross-linking step, known additional steps may be carried out as necessary, such as a step of recovering the self-cross-linked polysaccharide component, a drying step, a grinding step, and / or a surface treatment step for the polysaccharide.

[0124] The polymer contains the polysaccharide component as described above, and may further contain other components as needed. Examples of other components that may be contained together with the polysaccharide include, but are not limited to, an additional processing agent for the polysaccharide component or a polymer different from the polysaccharide component.

[0125] For example, the polymer may be in powder form and may further include a surface treatment agent bonded to the surface of the powder, which may contribute to improving the gel strength of the powder and ensuring absorption capacity under pressure.

[0126] The polymers exhibit good resorbability and biodegradability and may be used in a variety of applications.

[0127] For example, the polymers may be used as absorbent materials in hygiene products such as diapers and sanitary napkins, or other applications requiring absorption. If necessary, the polymers may be subjected to additional crosslinking, surface treatment, or physical grinding steps to enhance their effectiveness in the hygiene products or absorbent materials.

[0128] Accordingly, the present specification discloses absorbent materials or sanitary articles (eg, diapers, sanitary napkins, etc.) that include the polymers.

[0129] The specific method of applying the polymer to form the absorbent material or sanitary product is not particularly limited, and for example, the method of applying a conventional SAP to form the absorbent material or sanitary product may be similarly used. [Effects of the Invention]

[0130] This specification discloses a polymer. The polymer may be an absorbable polymer used to form a so-called SAP. By adjusting the materials and conditions used in the crosslinking process to form the SAP, such a polymer can be formed without using a so-called crosslinking agent or with a minimal amount of crosslinking agent, thereby exhibiting excellent absorption capacity. The polymer is formed by crosslinking a biodegradable material without using a crosslinking agent or with a minimal amount of crosslinking agent, thereby maximizing the biodegradability of the material. This specification further discloses uses of the polymer. [Brief explanation of the drawings]

[0131] [Figure 1] FIG. 1 is a 1H NMR spectrum of the acidic polysaccharide of Production Example 1. [Figure 2] FIG. 2 is a 1H NMR spectrum of the acidic polysaccharide of Example 3. [Figure 3] FIG. 3 is a 1H NMR spectrum of the acidic polysaccharide of Example 4. [Figure 4] FIG. 4 is a 1H NMR spectrum of the acidic polysaccharide of Example 5. [Figure 5] FIG. 5 is a 1H NMR spectrum of the acidic polysaccharide of Example 6. [Figure 6] FIG. 6 is a 1H NMR spectrum of the acidic polysaccharide of Example 7. [Figure 7] FIG. 7 is a 1H NMR spectrum of the acidic polysaccharide of Example 8. [Figure 8] FIG. 8 is a 1H NMR spectrum of the acidic polysaccharide of Example 9. [Figure 9] FIG. 9 is a 1H NMR spectrum of the acidic polysaccharide of Comparative Example 7. [Figure 10] FIG. 10 is a 1H NMR spectrum of the acidic polysaccharide of Comparative Example 8. [Figure 11] FIG. 11 is a 1H NMR spectrum of the acidic polysaccharide of Comparative Example 9. DETAILED DESCRIPTION OF THE INVENTION

[0132] Hereinafter, the polymers disclosed herein will be described in detail through examples and comparative examples, but the scope of the polymers is not limited to the following examples.

[0133] 1. Evaluation of Centrifuge Retention Capacity (CRC) CRC (Centrifuge Retention Capacity) was measured according to the EDANA (European Disposables and Nonwovens Association) WSP 241.3 standard. Approximately 0.2 g (W0) of polymer was placed in a nonwoven bag, sealed, and then immersed in saline. The saline solution used was a 0.9 wt% NaCl aqueous solution. This condition was maintained for approximately 30 minutes, and the bag was centrifuged at 250 G for 3 minutes to remove water, after which the mass of the bag (g, W2) was measured. The same procedure was repeated for the same nonwoven bag without the polymer, and the mass (g, W1) was measured.

[0134] The measurement results were substituted into the following formula A to calculate CRC (g / g).

[0135] The evaluation was carried out under constant temperature and humidity conditions (23±1° C., relative humidity: 50±10%).

[0136] [Formula A] CRC(g / g)={[W2(g)-W1(g)] / W0(g)}-1

[0137] 2. Molecular weight measurement of polysaccharide components Molecular weight was evaluated using the flow FFF (field-flow fractionation)-MALS (multiangle light scattering) method. This method involves connecting a flow FFF with a MALS (light scattering detector) that measures the intensity of scattered light at various angles to measure the molecular weight of a sample. The flow FFF / MALS device used was a Postnova AF2000. To measure molecular weight, the sample was dissolved in distilled water at a concentration of 5 mg / mL at 150°C in a hydrothermal reactor for 6 hours and filtered through a cellulose syringe filter. A 0.1 M aqueous solution of ammonium acetate (NH4OAc) was prepared and filtered through a solvent clarification system before being used as the mobile phase. The molecular weight of the sample was measured while it was flowing through the analytical channel (300 mm × 60 mm × 40 mm) under the following conditions: detector flow of 0.5 mL / min, injection flow of 0.4 mL / min, injection time of 10 min, cross flow of 0.5 mL / min, and transition time of 1 min.

[0138] 3. Measurement of amylopectin and amylose content The contents of amylopectin and amylose in the polysaccharide components were evaluated according to the method described in the paper (Potato Research 31 (1988) 241-246).

[0139] First, approximately 5 mg of starch sample was dissolved in approximately 1 mL of sterile water to prepare a sample (Step 1), and then heated in a 95°C water bath for approximately 15 minutes (Step 2).

[0140] Next, about 20 μl of the sample was placed in a cuvette (step 3), and about 980 μl of iodine solution was added and mixed (step 4).

[0141] Next, the absorbance of the sample mixed with the iodine solution was measured at wavelengths of 525 nm and 700 nm and recorded (Step 5). The absorbance was measured using an OPTIZEN POP model manufactured by KLAB.

[0142] Approximately 20 μl of water was placed in another cuvette, and 980 μl of iodine solution was added and mixed (Step 6). The absorbance of the solution from Step 6 was measured at wavelengths of 525 nm and 700 nm in the same manner as in Step 5, and recorded (Step 7).

[0143] The absorbance obtained in step 7 was subtracted from the absorbance obtained in step 5 to determine the percentage of amylose using the following formula E (step 8).

[0144]

number

[0145] In Equation E, PA is the percentage of amylose, and OD 700 is the absorbance at 700 nm measured in step 5 minus the absorbance at 700 nm measured in step 7, and OD 525 is the value obtained by subtracting the absorbance at 525 nm measured in step 7 from the absorbance at 525 nm measured in step 5.

[0146] 4.NMR analysis To evaluate the degree of substitution of starch, a polysaccharide component 1 H-NMR analysis was carried out in the following manner. 1The sample for H-NMR analysis was prepared by dissolving the polysaccharide components in water, adding methanol, stirring, filtering, and drying. 50 mg of the resulting sample was dissolved in a mixed solvent of 0.75 mL of DO and 0.25 mL of DO, which was the NMR measurement solvent, and stirred at 90°C for approximately 1 hour to prepare a sample. The sample turned deep yellow after stirring. 1 H NMR analysis was carried out at ambient temperature (approximately 25° C.) using a Varian Unity Inova (500 MHz) spectrometer with a triple-resonance 5 mm probe. 1 1 H NMR analysis was performed using a Bruker Avance Neo instrument.

[0147] Production Example 1: Production of acidic polysaccharide (A) 100 g of starch and 400 mL of IPA (isopropyl alcohol) were placed in a 500 mL round-bottom flask and stirred. The starch had a molecular weight of approximately 6.48 × 10 7 The average molecular weight of the mixture was approximately g / mol, and the weight ratio of amylose (AM) to amylopectin (AP) (AP:AM) was approximately 79:21. The weight ratio of amylose to amylopectin could be adjusted using the method described in Example 16. The external temperature was set to 60°C, and after waiting for temperature equilibrium to be achieved, approximately 39 g of an aqueous NaOH solution with a concentration of approximately 40 wt% was added, followed by 46 g of SMCA (sodium monochloro acetate). The mixture was stirred for at least 2 hours while maintaining the heating state at 60°C. The mixture was then allowed to cool to room temperature (approximately 25°C) and filtered. The solid obtained by filtering was washed several times with an aqueous 80 wt% MeOH (methanol) solution and dried to produce acidic polysaccharide (A).

[0148] FIG. 1 shows the polysaccharide components obtained by the above method. 11H NMR spectrum. The degree of substitution of this polysaccharide component was evaluated by the following method. First, the sum of the intergral 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, which are peaks within the range of 2.5 ppm to 3.6 ppm in the spectrum, was set to be 1. Next, the degree of substitution at carbon 2 (2-DS) was calculated as the sum of the intergral values ​​at the 3.34 ppm and 3.33 ppm (doublet, 0.23) and 2.57 ppm and 2.58 ppm (doublet, 0.20) peaks. The degree of substitution at carbon 3 (3-DS) was calculated by dividing the intergral values ​​at the 2.39 ppm and 2.41 ppm (0.20) peaks by 2. The degree of substitution at carbon 6 (6-DS) was calculated by dividing the intergral values ​​at the 2.14 ppm and 2.15 ppm (0.19) peaks by 2.

[0149] Next, the degree of substitution was calculated by adding up all the above degrees of substitution (2-DS+3-DS+6-DS). The degree of substitution calculated in this manner was about 0.6.

[0150] Example 1 The acidic polysaccharide component of Production Example 1 was dispersed in 10 times the amount of distilled water, and a 0.5N aqueous HCl solution was added to adjust the pH of the mixture to about 6.0.

[0151] The pH-adjusted mixture was then applied to a thickness of about 0.2 to 0.5 cm and heat-treated in an oven at about 120°C for about 3 hours to allow for a self-crosslinking reaction. The self-crosslinked polymer was then crushed and classified to produce particulate polymer with a size ranging from about 150 μm to 850 μm.

[0152] Example 2. A particulate polymer was produced in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 6.5.

[0153] Comparative Example 1 A particulate polymer was produced in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 4.5.

[0154] Comparative Example 2 A particulate polymer was produced in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 5.0.

[0155] Comparative Example 3. A particulate polymer was produced in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 5.5.

[0156] Comparative Example 4. A particulate polymer was produced in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 7.0.

[0157] Comparative Example 5. A particulate polymer was produced in the same manner as in Example 1, except that the pH of the mixture was adjusted to about 8.0 using 0.5N NaOH aqueous solution instead of 0.5N HCl aqueous solution.

[0158] Comparative Example 6. A particulate polymer was produced in the same manner as in Comparative Example 5, except that the pH of the mixture was adjusted to about 9.0.

[0159] The CRC evaluation results of the polymers of the above Examples and Comparative Examples are summarized in Table 1 below.

[0160] [Table 1]

[0161] The results in Table 1 show that polymers with the desired absorbency cannot be obtained if the pH is too low or too high during the self-crosslinking process. These results are believed to be due to the fact that if the self-crosslinking reaction, which is promoted under acidic conditions, occurs too quickly or too slowly depending on the pH, the absorbency decreases or leakage of the polymer solution occurs during the absorption process.

[0162] Example 3 An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, but with a degree of substitution of about 0.4. The degree of substitution can be adjusted by adjusting the amount of SMCA (sodium monochloro acetate) used during the preparation process. Typically, about 90% by weight of the applied SMCA reacts with starch to introduce carboxyl groups. Taking this into consideration, the amount of SMCA used was changed to about 30 g, and the amount of NaOH aqueous solution (40% by weight) added was changed to about 25 g, thereby producing an acidic polysaccharide with a degree of substitution of about 0.4.

[0163] FIG. 2 shows the acidic polysaccharides produced 1 The degree of substitution was determined by the same method as in Preparation Example 1 and was found to be about 0.4. The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0164] Example 4. An acidic polysaccharide was produced in the same manner as in Production Example 1, except that the amount of SMCA (sodium monochloro acetate) was adjusted to about 37 g, and the amount of NaOH aqueous solution (40 wt%) added was changed to about 30.5 g, thereby obtaining an acidic polysaccharide with a degree of substitution of about 0.5. 1 The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0165] Example 5. An acidic polysaccharide was produced in the same manner as in Production Example 1, except that the amount of SMCA (sodium monochloro acetate) was adjusted to about 52 g, and the amount of NaOH aqueous solution (40 wt%) added was changed to about 43 g, thereby obtaining an acidic polysaccharide with a degree of substitution of about 0.7. 1The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0166] Example 6 An acidic polysaccharide was produced in the same manner as in Production Example 1, except that the amount of SMCA (sodium monochloro acetate) was adjusted to about 58 g, and the amount of NaOH aqueous solution (40 wt%) added was changed to about 49 g, thereby obtaining an acidic polysaccharide with a degree of substitution of about 0.8. 1 The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0167] Example 7 An acidic polysaccharide was produced in the same manner as in Production Example 1, except that the amount of SMCA (sodium monochloro acetate) was adjusted to about 65 g, and the amount of NaOH aqueous solution (40 wt%) added was changed to about 55 g, thereby obtaining an acidic polysaccharide with a degree of substitution of about 0.9. 1 The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0168] Example 8 An acidic polysaccharide was produced in the same manner as in Production Example 1, except that the amount of SMCA (sodium monochloro acetate) was adjusted to about 72 g, and the amount of NaOH aqueous solution (40 wt%) added was changed to about 61 g, thereby obtaining an acidic polysaccharide with a degree of substitution of about 1.0. 1 The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0169] Example 9. An acidic polysaccharide was produced in the same manner as in Production Example 1, except that the amount of SMCA (sodium monochloro acetate) was adjusted to about 99 g, and the amount of NaOH aqueous solution (40 wt%) added was changed to about 83 g, thereby obtaining an acidic polysaccharide with a degree of substitution of about 1.2. 1 The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0170] Example 10. An acidic polysaccharide was prepared in the same manner as in Preparation Example 1, except that an excess amount (approximately 120 g or more) of SMCA (sodium monochloro acetate) was added, and the amount of NaOH aqueous solution (40 wt%) added was changed to approximately 100 g, yielding an acidic polysaccharide with a degree of substitution of approximately 1.4. The acidic polysaccharide was then subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0171] Example 11 The process of Example 10 for preparing an acidic polysaccharide was repeated twice to obtain an acidic polysaccharide with a degree of substitution of about 1.6. The acidic polysaccharide was then subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0172] Comparative Example 7. An acidic polysaccharide was produced in the same manner as in Production Example 1, but the amount of SMCA (sodium monochloro acetate) was adjusted to about 22 g to obtain an acidic polysaccharide with a degree of substitution of about 0.3. 1 The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0173] Comparative Example 8. The process of Example 10 for preparing an acidic polysaccharide was repeated four times to obtain an acidic polysaccharide with a degree of substitution of about 2.1. 1The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0174] Comparative Example 9. The process of Example 10 for preparing an acidic polysaccharide was repeated five times or more to obtain an acidic polysaccharide with a degree of substitution of about 2.5. 1 The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0175] Comparative Example 10. 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 reaction process for self-crosslinking. In this case, the EG functioned as an internal crosslinking agent, and therefore the obtained polymer was not a self-crosslinked polymer.

[0176] Comparative Example 11. 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 0.5 wt% during the reaction process for self-crosslinking. In this case, the EG functioned as an internal crosslinking agent, and therefore the obtained polymer was not a self-crosslinked polymer.

[0177] The CRC evaluation results of the polymers of the above Examples and Comparative Examples are summarized in Table 2 below.

[0178] [Table 2]

[0179] From the results in Table 2, it can be seen that if the amount of carboxyl groups required for self-crosslinking is too large, an excessively dense crosslinked structure is realized, the proportion of polar functional groups decreases, and absorbency decreases. Also, if the amount of carboxyl groups is too small, crosslinking does not occur sufficiently, again resulting in reduced absorbency. In the case of Comparative Example 9, where the degree of substitution was not properly adjusted, the desired absorbency could not be obtained even when an internal crosslinking agent (EG) was added.

[0180] Example 12 Acidic polysaccharides were produced in the same manner as in Production Example 1, except that the molecular weight of the starch was about 3.64 × 10 5 The acidic polysaccharide was produced using starch with a weight ratio of amylose (AM) to amylopectin (AP) (AP:AM) of approximately 79:21, and a degree of substitution of approximately 0.7.

[0181] The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0182] Example 13 Acidic polysaccharides were produced in the same manner as in Production Example 1, except that the molecular weight of the starch was about 8.72 × 10 6 The acidic polysaccharide was produced using starch with a weight ratio of amylose (AM) to amylopectin (AP) (AP:AM) of approximately 79:21, and a degree of substitution of approximately 0.7.

[0183] The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0184] Example 14. Acidic polysaccharides were produced in the same manner as in Production Example 1, except that the molecular weight of the starch was about 3.29 × 10 5 The acidic polysaccharide was produced using starch with a weight ratio of amylose (AM) to amylopectin (AP) (AP:AM) of approximately 79:21, and a degree of substitution of approximately 0.7.

[0185] The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0186] Example 15. Acidic polysaccharides were produced in the same manner as in Production Example 1, except that the molecular weight of the starch was about 5.20 × 10 7 The acidic polysaccharide was produced using starch with a weight ratio of amylose (AM) to amylopectin (AP) (AP:AM) of approximately 79:21, and a degree of substitution of approximately 0.7.

[0187] The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0188] The CRC evaluation results for the polymers of the above examples are summarized in Table 3 below.

[0189] [Table 3]

[0190] Example 16. Acidic polysaccharides were prepared in the same manner as in Preparation Example 1, except that the weight ratio of amylose (AM) to amylopectin (AP) (AP:AM) was adjusted to about 72:28. The molecular weight of the starch thus prepared was about 1 x 10 7 g / mol level, and the degree of substitution of the acidic polysaccharide was about 0.7.

[0191] The amylose to amylopectin ratio of the starch may be adjusted using n-butanol as follows: First, approximately 10 g of starch is mixed with 10 mL of ethanol and approximately 300 mL of distilled water and stirred at approximately 90°C until the mixture becomes clear. Next, 200 mL of a mixture of n-butanol and isoamyl alcohol in a 3:1 volume ratio (n-butanol:isoamyl alcohol) is added to the clear mixture, and the mixture is heated for an additional 20-30 minutes (approximately 90°C) until the mixture becomes clear. The mixture is then allowed to cool to room temperature (approximately 25°C) and stored at approximately 4°C for approximately 24 hours. The mixture is then centrifuged (3000 × g, 20 minutes), washed with ethanol, and dried to obtain starch. Because amylose selectively precipitates with n-butanol, the starch obtained through this process has a higher amylose content than conventional starch. This process may be repeated until the desired amylose content is obtained.

[0192] The acidic polysaccharide was subjected to self-crosslinking in the same manner as in Example 2 to obtain a self-crosslinked polymer.

[0193] Comparative Example 12. The acidic polysaccharide and the self-crosslinked polymer were prepared in the same manner as in Example 16, except that starch (waxy corn starch) with an amylose (AM) to amylopectin (AP) weight ratio (AP:AM) of about 96:4 was used.

[0194] Comparative Example 13. Acidic polysaccharides and self-crosslinked polymers were prepared in the same manner as in Example 16, except that the weight ratio of amylose (AM) to amylopectin (AP) (AP:AM) was adjusted to about 61:39.

[0195] Comparative Example 14. Acidic polysaccharides and self-crosslinked polymers were prepared in the same manner as in Example 16, except that the weight ratio of amylose (AM) to amylopectin (AP) (AP:AM) was adjusted to about 48:52.

[0196] Comparative Example 15. Acidic polysaccharides and self-crosslinked polymers were prepared in the same manner as in Example 16, except that the weight ratio of amylose (AM) to amylopectin (AP) (AP:AM) was adjusted to about 40:60.

[0197] The CRC evaluation results for the polymers are summarized in Table 4 below.

[0198] [Table 4]

Claims

1. containing a self-crosslinked polysaccharide component, A polymer having a centrifugal water retention capacity of 30 g / g or more according to EDANA (European Disposables and Nonwovens Association) method WSP 241.

3.

2. The polymer of claim 1 , wherein the polysaccharide component is a starch.

3. 10. The polymer of claim 1 comprising at least 80% by weight of said self-crosslinked polysaccharide component.

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

5. The polymer according to claim 1 , wherein F in the following formula 1 is 2.00 or more. [Formula 1] F=AP×DS×Log(Mw) In Equation 1, AP is the proportion 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. 6. The polymer of claim 5, wherein AP in Formula 1 is in the range of 0.7 to 0.

9.

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

0.

8. 6. The polymer of claim 5, wherein the Mw of Formula 1 is 10 million or greater.

9. 2. The polymer of claim 1, wherein the self-crosslinked polysaccharide component comprises a polymer chain comprising monosaccharide units linked by glycosidic bonds and a bond of the formula 1 below connecting the polymer chains. 【Chemistry 1】 In Chemical Formula 1, L １ is an alkylene group, an alkylidene group, or a bond represented by the following formula 2, and L ２ is a single bond or -(CH ２ )-O-. 【Chemistry 2】

10. 10. The polymer of claim 9, wherein the monosaccharide unit has a ring structure containing carbon and oxygen atoms as ring atoms, and the bond of formula (I) is connected to the carbon atom of the ring structure directly or through a methylene group.

11. The polymer according to claim 9 , wherein the polysaccharide component comprises a unit represented by the following formula: 【Transformation 3】 In Chemical Formula 3, R １ represents a hydroxy group, an amino group, -L ５ -C(=O)-OH, -L ５ -C(=O)-O － or a functional group of the following formula 4, R ３ represents a hydroxy group, -L ５ -C(=O)-OH, -L ５ -C(=O)-O － or a functional group of the following formula 4, ３ and L ４ is a single bond, and the other is CHR ２ and R ２ is a hydroxyl group, -L ５ -C(=O)-OH, -L ５ -C(=O)-O － or a functional group of the following formula 4, ５ is an alkylene group or an alkylidene group, １ ~R ３ is an oxygen atom in the bond of the formula (1) (excluding the oxygen atom in the carbonyl group). 【Chemistry 4】 In Chemical Formula 4, M １ is hydrogen or a metal, and the M １ is the metal, １ The bond is an ionic bond.

12. A method for producing a 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 more and less than 7.

13. The method for producing a polymer according to claim 12 , wherein the acidic polysaccharide component has F in the following formula 1 of 2.00 or more: [Formula 1] F=AP×DS×Log(Mw) In Equation 1, AP is the proportion 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 a polymer according to any one of claims 1 to 11.

15. Hygiene article comprising a polymer according to any one of claims 1 to 11.

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