Modified polysaccharide

Abstract

To provide modified polysaccharide excellent in ability to prevent recontamination.SOLUTION: Polysaccharides having hydroxyl groups are modified polysaccharides that are esterified (substituted) by carboxylic acids or their salts having two or more carboxyl groups, and the degree of substitution (DS) of the modified polysaccharides by the carboxylic acid or its salt per monosaccharide unit is 1 or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to modified polysaccharides, and more particularly to modified polysaccharides useful in detergents and the like. [Background technology]

[0002] 2. Description of the Related Art Detergents used for clothing have conventionally been blended with detergent builders (detergent assistants) such as zeolite and polyethylene glycol in order to improve the cleaning effect of the detergent. In addition to the above-mentioned various detergent builders, in recent years, polymers have been blended into detergent compositions as detergent builders. For example, polycarboxylic acid polymers are polymers having a carboxyl group or a salt thereof in the molecule, and are preferably used in detergent applications because of their excellent dispersibility for inorganic particles and the like.

[0003] However, polymers such as polycarboxylic acid polymers have low biodegradability and have a problem in terms of their impact on the environment. In recent years, from the viewpoint of reducing the environmental load, techniques using highly biodegradable raw materials such as polysaccharides have been developed. For example, Patent Document 1 discloses a method for producing low substituted (DS) dextrins and starch esters, which comprises heating dextrin or thin boiling starch in the presence of a dibasic organic acid anhydride. Patent Document 2 discloses a method for producing a glucose polymer having ion exchange capacity, which comprises drying a mixed aqueous solution of a raw glucose polymer and a polycarboxylic acid to form a uniform powder, and then subjecting the powder to a heat treatment. Patent Document 3 discloses an anhydride-modified starch prepared from a base starch having (i) a degree of substitution of 10% to 80% and (ii) an average molecular weight of 15,000 to 200,000 g / mol. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 3,732,207 [Patent Document 2] JP 2004-307768 A [Patent Document 3] Special Publication No. 2022-548022 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, various modified polysaccharides obtained by using polysaccharides and carboxylic acids have been developed. However, the conventional modified polysaccharides are not sufficient in terms of soil redeposition prevention ability.

[0006] The present invention has been made in view of the above-mentioned circumstances, and has an object to provide a modified polysaccharide having excellent anti-soil redeposition ability. [Means for solving the problem]

[0007] The present inventors have conducted extensive research into modified polysaccharides and have found that modified polysaccharides obtained by esterifying (substituting) the hydroxyl groups of polysaccharides with carboxylic acids or salts thereof having two or more carboxyl groups and having a degree of substitution (DS) per monosaccharide unit with said carboxylic acids or salts thereof of 1 or more have excellent anti-soil redeposition properties. They have thus come to the realization that the above-mentioned problems can be solved in an excellent manner and have thus arrived at the present invention.

[0008] The present invention includes the following modified polysaccharides, etc. [1] A modified polysaccharide in which the hydroxyl groups of a polysaccharide are esterified (substituted) with a carboxylic acid or a salt thereof having two or more carboxyl groups, and the degree of substitution (DS) of the carboxylic acid or the salt thereof per monosaccharide unit is 1 or more. [2] The modified polysaccharide according to [1] above, wherein the polysaccharide is starch and / or cellulose. [3] The modified polysaccharide according to [1] or [2] above, wherein the carboxylic acid is an anhydride of a dicarboxylic acid. [4] A detergent composition comprising the modified polysaccharide according to any one of [1] to [3] above. Effect of the Invention

[0009] The modified polysaccharide of the present invention has the above-mentioned constitution and is excellent in anti-soil redeposition ability and biodegradability, and therefore can be suitably used in detergents and the like. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The preferred embodiments of the present invention are specifically described below, but the present invention is not limited to the following description, and can be modified as appropriate within the scope of the present invention. In addition, a combination of two or more of the individual preferred embodiments of the present invention described below also falls within the preferred embodiments of the present invention.

[0011] 1. Modified polysaccharides The modified polysaccharide of the present invention is a modified polysaccharide in which the hydroxyl groups of the polysaccharide are esterified (substituted) with a carboxylic acid or a salt thereof having two or more carboxyl groups (hereinafter also referred to as a polyvalent carboxylic acid), and the modified polysaccharide has a degree of substitution (DS) per monosaccharide unit with the carboxylic acid or the salt thereof of 1 or more. When the degree of substitution is 1 or more, the amount of carboxyl groups or salt groups thereof in the modified polysaccharide is sufficient, resulting in excellent dispersibility of stains and excellent anti-soil redeposition ability. Furthermore, by modifying a polysaccharide through esterification with a polyvalent carboxylic acid, the modified polysaccharide becomes highly biodegradable. The degree of substitution of the modified polysaccharide is preferably 1.5 to 3, and more preferably 2 to 3, from the viewpoint of anti-soil redeposition ability. From the viewpoint of biodegradability, the degree of substitution of the modified polysaccharide is preferably 1.2 to 3, more preferably 1.5 to 2.5. The degree of substitution can be calculated by the method described in the Examples.

[0012] The weight average molecular weight of the modified polysaccharide is not particularly limited, but is preferably 5,000 to 100,000, more preferably 8,000 to 80,000, and even more preferably 10,000 to 50,000. The weight average molecular weight of the modified polysaccharide can be measured by the method described in the Examples.

[0013] The carboxylic acid used for the esterification of the polysaccharide is not particularly limited as long as it is a polyvalent carboxylic acid having two or more carboxyl groups in one molecule, and specific examples thereof include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, fumaric acid, maleic acid, oxaloacetic acid, tartaric acid, malic acid, itaconic acid, and citraconic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid; tricarboxylic acids such as aconitic acid, citric acid, and trimellitic acid; tetracarboxylic acids such as pyromellitic acid, and anhydrides thereof, and derivatives in which substituents are bonded thereto. One or more of these can be used.

[0014] The salt of the polyvalent carboxylic acid is not particularly limited, but examples thereof include alkali metal salts such as lithium salts, sodium salts, and potassium salts; alkaline earth metal salts such as calcium salts and magnesium salts; ammonium salts; and organic amine salts such as alkanolamines (e.g., ethanolamine, diethanolamine, and triethanolamine groups) and triethylamine.

[0015] The substituent in the derivative of the polyvalent carboxylic acid is not particularly limited, and examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms.

[0016] Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an n-pentyl group (amyl group), an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, an n-icosyl group, an i-propyl group, a sec-butyl group, an i-butyl group, a t-butyl group, a 1-methylbutyl group, a 1-ethylpropyl group, a 2-methylbutyl group, an i-amyl group, a neopentyl group, a 1,2-dimethylpropyl group, a 1,1-dimethylpropyl group, a t-amyl group, a 1,3-dimethylbutyl group, and a 3,3-dimethylbutyl group. aliphatic alkyl groups such as 2-ethylbutyl group, 2-ethyl-2-methylpropyl group, 1-methylheptyl group, 2-ethylhexyl group, 1,5-dimethylhexyl group, t-octyl group, branched nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, stearyl group, and icosyl group; alicyclic alkyl groups such as cyclopropyl group, cyclopropylmethyl group, cyclobutyl group, cyclobutylmethyl group, cyclopentyl group, cyclohexyl group, cyclohexylmethyl group, cycloheptyl group, cyclooctyl group, cyclohexylpropyl group, cyclododecyl group, norbornyl group (C7), adamantyl group (C10), and cyclopentylethyl group.

[0017] Examples of the alkenyl group include a vinyl group, an allyl group, a 1-butenyl group, a 2-butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, a dodecenyl group, an octadecenyl group, and an icosenyl group. Examples of the alkynyl group include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a butynyl group, a pentynyl group, a hexynyl group, a heptynyl group, an octynyl group, a nonynyl group, a decynyl group, a dodecynyl group, an octadecynyl group, and an icosynyl group. Examples of the aryl group include aryl groups such as a phenyl group, a benzyl group, a phenethyl group, an o-, m- or p-tolyl group, a 2,3- or 2,4-xylyl group, a mesityl group, a naphthyl group, an anthryl group, a phenanthryl group, a biphenylyl group, a benzhydryl group, a trityl group and a pyrenyl group.

[0018] The substituent in the derivative of the polyvalent carboxylic acid is preferably an alkyl group having 1 to 20 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms.

[0019] The polyvalent carboxylic acid is preferably an aliphatic dicarboxylic acid, anhydride thereof, or a derivative thereof, more preferably succinic acid, maleic acid, anhydride thereof, or a derivative thereof having an alkyl group having 1 to 20 carbon atoms bonded thereto, and even more preferably succinic anhydride. When the polyvalent carboxylic acid is an anhydride, the crosslinking reaction can be more sufficiently inhibited from proceeding during the esterification. The number of carbon atoms in the polyvalent carboxylic acid is not particularly limited, but is preferably 2 to 12, more preferably 4 to 8, and further preferably 4 to 6. When the polycarboxylic acid has a substituent, the number of carbon atoms of the polycarboxylic acid includes the number of carbon atoms of the substituent.

[0020] Examples of the derivatives of succinic acid include methylsuccinic anhydride, ethylsuccinic anhydride, propylsuccinic anhydride, butylsuccinic anhydride, pentylsuccinic anhydride, hexylsuccinic anhydride, heptylsuccinic anhydride, octylsuccinic anhydride, decylsuccinic anhydride, dodecylsuccinic anhydride, tridecylsuccinic anhydride, tetradecylsuccinic anhydride, pentadecylsuccinic anhydride, and hexadecylsuccinic anhydride. alkylene-dicarboxylic acid anhydrides such as heptadecylsuccinic anhydride, octadecylsuccinic anhydride, isooctadecylsuccinic anhydride, etc.; alkenylene-dicarboxylic acid anhydrides such as propenylsuccinic anhydride, butenylsuccinic anhydride, pentenylsuccinic anhydride, hexenylsuccinic anhydride, heptenylsuccinic anhydride, octenylsuccinic anhydride, decenylsuccinic anhydride, dodecenylsuccinic anhydride, etc.

[0021] The polysaccharides used as the raw material for the modified polysaccharide of the present invention are not particularly limited as long as they have monosaccharides such as glucose, galactose, mannose, fructose, etc. as constituent units, and examples thereof include starch, cellulose (β-1,4-glucan), glycogen, agarose, carrageenan, xanthan gum, dextran, dextrin, glucomannan, β-1,3-glucan, α-1,2-glucan, α-1,3-glucan, etc. The monosaccharides constituting the polysaccharides are preferably aldoses having 5 to 7 carbon atoms, more preferably aldoses having 6 carbon atoms, and even more preferably glucose. The polysaccharides may be natural polysaccharides isolated from plant sources or synthetic polysaccharides. Examples of natural starches include those obtained from plants such as potato, wheat, corn, rice, tapioca, sago, barley, pea, quinoa, and cassava.

[0022] The polysaccharide is preferably starch or cellulose, more preferably starch. The starch may be any one containing amylose and / or amylopectin, and may be solubilized by acid treatment or the like.

[0023] The average molecular weight of the polysaccharide is not particularly limited, but is preferably 2,000 to 100,000, more preferably 2,000 to 50,000, and even more preferably 2,000 to 10,000. The average molecular weight of the polysaccharide can be measured by gel permeation chromatography.

[0024] The modified polysaccharide has a structure in which the hydroxyl groups of the raw material polysaccharide are esterified (substituted) with the polyvalent carboxylic acids, and the degree of substitution (DS) with the carboxylic acid or a salt thereof per monosaccharide unit is not limited to 1. The modified polysaccharide may have unesterified hydroxyl groups, or a compound other than the polyvalent carboxylic acids may be bonded to the hydroxyl groups. In the modified polysaccharide, the degree of substitution of hydroxyl groups with compounds other than polycarboxylic acids is not particularly limited as long as the degree of substitution with polycarboxylic acids is 1 or more, but is preferably 2 or less.

[0025] The compounds other than polyvalent carboxylic acids that may be bonded to the hydroxyl groups of the polysaccharides are not particularly limited as long as they have a functional group capable of reacting with the hydroxyl groups. Examples of the functional group capable of reacting with a hydroxyl group include a carboxyl group or a salt thereof, an epoxy group, a hydroxyl group, etc. Preferred are a carboxyl group or a salt thereof, and an epoxy group.

[0026] The compound other than the polyvalent carboxylic acids may be any compound having a functional group capable of reacting with a hydroxyl group, but it is preferable that the compound has a hydrophobic group. Examples of the hydrophobic group include the above-mentioned alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, alkynyl groups having 2 to 20 carbon atoms, and aryl groups having 6 to 20 carbon atoms.

[0027] Preferable examples of the compound other than polyvalent carboxylic acids include monovalent carboxylic acids, epoxy compounds, and alcohols.

[0028] Examples of the monovalent carboxylic acids include saturated fatty acids such as acetic acid, propionic acid, butyric acid, valeric acid, pivalic acid, caproic acid, enanthic acid, caprylic acid, 2-ethylhexanoic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, and arachidic acid; and saturated fatty acids such as acrylic acid, methacrylic acid, crotonic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, and gadolinium acid. Examples of such fatty acids include monounsaturated fatty acids such as linoleic acid, eicosadienoic acid, etc.; diunsaturated fatty acids such as linoleic acid, eicosadienoic acid, etc.; triunsaturated fatty acids such as α-linolenic acid, γ-linolenic acid, pinoleic acid, eleostearic acid, mead acid, dihomo-γ-linolenic acid, eicosatrienoic acid, etc.; tetraunsaturated fatty acids such as stearidonic acid, arachidonic acid, eicosatetraenoic acid, etc.; pentaunsaturated fatty acids such as bosseopentaenoic acid, eicosapentaenoic acid, docosapentaenoic acid, etc., and salts thereof.

[0029] Examples of the epoxy compound include propylene oxide, 2,3-butylene oxide, isobutylene oxide, 1,2-butylene oxide, 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2-epoxypentane, 1,3-butadiene monoxide, glycidyl methyl ether, ethyl glycidyl ether, glycidyl isopropyl ether, tert-butyl glycidyl ether, 2-(chloromethyl)-1,2-epoxypropane, glycidol, epichlorohydrin, epibromohydrin, butyl glycidyl ether, 1,2-epoxyhexane, 2-(chloromethyl)-1,2-epoxybutane, allyl glycidyl ether, tetracyanoethylene oxide, glycidyl butyrate, glycidyl methacrylate, 1-methyl-1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 3,4-epoxytetrahydrofuran, and 2,3-epoxynorbornene.

[0030] Examples of the alcohols include aliphatic alcohols having 1 to 20 carbon atoms, such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 1-hexanol, 2-hexanol, 3-hexanol, octanol, 2-ethyl-1-hexanol, nonyl alcohol, lauryl alcohol, cetyl alcohol, and stearyl alcohol; alicyclic alcohols having 3 to 20 carbon atoms, such as cyclohexanol; and unsaturated alcohols having 3 to 20 carbon atoms, such as (meth)allyl alcohol, 3-buten-1-ol, and 3-methyl-3-buten-1-ol.

[0031] 2. Manufacturing method of modified polysaccharides The method for producing the modified polysaccharide of the present invention is not particularly limited, and the modified polysaccharide can be obtained by reacting a raw material polysaccharide with a polyvalent carboxylic acid or a salt thereof, or an anhydride thereof. The present invention also relates to a method for producing a modified polysaccharide, which comprises a step of reacting a polysaccharide with a polyvalent carboxylic acid or a salt thereof, or an anhydride thereof. Specific examples and preferred forms of the raw material polysaccharides and polyvalent carboxylic acids or their salts or anhydrides are as described above.

[0032] In the above reaction step, the amount of polyvalent carboxylic acid used is not particularly limited and may be determined in consideration of the desired degree of substitution, but the amount of polyvalent carboxylic acid used per monosaccharide unit of polysaccharide (molar ratio) is preferably 1.1 to 20, more preferably 1.5 to 15, even more preferably 1.8 to 10, and particularly preferably 2 to 8.

[0033] In the reaction step between the polysaccharide and the polyvalent carboxylic acid, a catalyst such as a base or an acid may be used. It is preferable to use a base catalyst in the reaction step. The base catalyst is, for example, a hydroxide, carbonate, or hydrogen carbonate of an alkali metal such as sodium or potassium. Preferably, it is a carbonate of an alkali metal, and more preferably potassium carbonate.

[0034] In the reaction step of the polysaccharide with the polyvalent carboxylic acid, a solvent is preferably used. The solvent is not particularly limited, and examples thereof include water; alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, and tert-butanol; aliphatic or alicyclic hydrocarbons such as n-hexane, n-pentane, and cyclohexane; aromatic hydrocarbons such as benzene and toluene; aliphatic or aromatic halides such as chloroform, chlorobenzene, and dichlorobenzene; nitriles such as acetonitrile and benzonitrile; ethers such as diethyl ether, diphenyl ether, anisole, 1,2-dimethoxyethane, and 1,4-dioxane; ketones such as acetone, methyl isopropyl ketone, and methyl isobutyl ketone; esters such as ethyl acetate and ethyl propionate; N-alkyllactams such as N-methyl-2-pyrrolidone; N,N-dialkylamides such as N,N-dimethylformamide and N,N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide; and sulfolanes such as sulfolane. The solvent is preferably water, ethers, or sulfoxides, and more preferably water, anisole, or dimethyl sulfoxide.

[0035] 3. Uses of modified polysaccharides The modified polysaccharide of the present invention can be suitably used for detergent builders, detergents, water treatment agents, dispersants, fiber treatment agents, scale inhibitors (scale inhibitors), cement additives, metal ion sequestering agents, thickeners, various binders, etc. Among these, it can be more suitably used for detergent builders, detergents, water treatment agents, and dispersants, and more preferably for use in laundry detergents.

[0036] The present invention further relates to a detergent builder, a detergent, a detergent composition, a water treatment agent, or a dispersant containing, as an essential component, the modified polysaccharide of the present invention or the modified polysaccharide produced by the production method of the present invention. The detergent and detergent composition of the present invention may be in a solid or liquid form, and may be for use in dishwashing or laundry, with laundry use being preferred.

[0037] The content of the modified polysaccharide of the present invention in the detergent or detergent composition of the present invention is preferably 0.1 to 15% by mass, more preferably 0.3 to 10% by mass, and even more preferably 0.5 to 5% by mass, based on the total amount of the detergent or cleaning composition.

[0038] The detergent and detergent composition of the present invention may contain, in addition to the modified polysaccharide of the present invention, one or more other components such as a solvent, a surfactant, a cleaning auxiliary additive, and an encapsulating agent. Examples of cleaning auxiliary additives include builders, surfactants or thickeners, mud stain removal / redeposition prevention agents, polymer stain release agents, polymer dispersants, polymer grease cleaning agents, enzymes, enzyme stabilizing systems, bleaching compounds, bleaching agents, bleach activators, bleaching catalysts, brighteners, dyes, hueing agents, dye transfer inhibitors, chelating agents, foam suppressors, fabric softeners, fragrances, and the like, and these may be used alone or in combination of two or more. EXAMPLES

[0039] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, unless otherwise specified, "parts" means "parts by weight" and "%" means "% by mass".

[0040] <Conditions for measuring the weight-average molecular weight of modified products> Equipment: Alliance HPLC (Waters) Detector: Waters 2414 RI Detector Column: OHpak SB-806M HQ x 2, OHpak SB-G 6B, manufactured by Resonac Inc. Column temperature: 40℃ Flow rate: 1.0mL / min Eluent: 100 mM phosphate buffer / acetonitrile = 92 / 8 (w / w) Calibration curve: Polyacrylic acid standard manufactured by American Polymer Standards

[0041] <Example 1> 14.32 g of dimethyl sulfoxide, 2.71 g of succinic anhydride, 0.59 g of anisole, and 0.19 g of potassium carbonate were charged into a glass reaction vessel and stirred at room temperature until uniformly dissolved. Then, 2.20 g of soluble starch (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to the reaction vessel and stirred at room temperature. After 42 hours, the stirring was stopped and the suspension after the reaction was dropped into 300 mL of ethanol to precipitate the product. The precipitate was then collected by filtration and washed with a small amount of ethanol. The precipitate was further dried under reduced pressure at 60°C for 3 hours to obtain modified product (1). The degree of substitution of modified product (1) estimated from the acid value measurement was 1.34. The weight average molecular weight of the modified product was 22,000.

[0042] <Example 2> 11.26 g of dimethyl sulfoxide, 6.40 g of succinic anhydride, 0.46 g of anisole, and 0.15 g of potassium carbonate were charged into a glass reaction vessel and stirred at room temperature until uniformly dissolved. Then, 1.73 g of soluble starch was added to the reaction vessel and stirred at room temperature. After 120 hours, the stirring was stopped and the suspension after the reaction was dropped into 300 mL of ethanol to precipitate the product. The precipitate was then collected by filtration and washed with a small amount of ethanol. The precipitate was further dried under reduced pressure at 60°C for 3 hours to obtain modified product (2). The degree of substitution of modified product (2) estimated from the acid value measurement was 2.37. The weight average molecular weight of the modified product was 33,100.

[0043] <Substitution degree (DS)> 1) Acid value measurement 0.20 g of the modified product was collected in a 100 mL beaker and dissolved in 60 mL of pure water / acetonitrile (=50 / 50 vol%). The acid value of the modified product was then measured by neutralization titration using an automatic titrator (HIRANUMA COM-A19). 2) Degree of substitution Acid value: AV (mgKOH / g) is the number of mg of KOH required to neutralize the acid components in 1 g of sample. The AV of succinic acid modified starch can be written as follows, where the degree of substitution of polysaccharide is x, the molecular weight of potassium hydroxide is 56, the molecular weight of succinic anhydride is 100, and the molecular weight of glucose structural unit is 162. AV = 1000 x 56 x x / (162 + 100 x x) Transforming the formula, we get x=162×AV / (1000×56-100×AV) In the above 1) acid value measurement, the acid value of each sample determined by neutralization titration was substituted for AV in the formula to calculate the degree of substitution x.

[0044] <Measurement of anti-redeposition ability> The following washing process, rinsing process, and drying process were carried out in this order, and the ability to prevent soil redeposition on the fabric was measured. Washing process: The following two types of cotton cloth were used for washing. Cotton cloth (1): Five pieces of cotton knit cloth (manufactured by Tanigashira Shoten) measuring 5 cm x 5 cm were prepared as recontamination judgment cloths. Cotton cloth (2): Cotton cloth obtained from Testfabrics was combined with cotton cloth (1) to give a total weight of 30 g. A detergent solution containing 4.37 g of sodium carbonate, 4.16 g of polyoxyethylene lauryl ether, 2.06 g of sodium sulfate, 11.61 g of linear alkylbenzenesulfonate (16%), 0.65 g of sodium chloride, 0.08 g of sodium sulfite, and 977.07 g of pure water was prepared. In addition, an aqueous solution of sodium bicarbonate consisting of 15.44 g of sodium bicarbonate, 100 g of 0.1N hydrochloric acid, and 884.6 g of pure water, and 3000 dH hard water were prepared from 59.00 g of calcium chloride dihydrate, 27.20 g of magnesium chloride hexahydrate, and 913.8 g of pure water. In addition, a 1% by mass aqueous solution of the modified product obtained in the manufacturing example was prepared. A mixed solution of 4055.46 g of pure water, 5.76 g of the above 3000 dH hard water, and 172.8 g of detergent solution was prepared in a plastic container, and 882.1 g was divided into 1 L pots for a Tergot-o-meter (manufactured by Daiei Scientific Co., Ltd., product name: TM-4). 4.5 g of sodium bicarbonate aqueous solution, 0.18 g of synthetic zeolite, 8.24 g of a 1 mass % aqueous solution of the modified product, and 5.00 g of pure water were added to each pot and stirred. After that, 1.8 g of ordinary red clay was added and stirred, and then cotton cloths (1) and (2) were added and washed at a stirring speed of 120 rpm at 25° C. for 10 minutes. Rinse step: After the washing step, the washed items were dehydrated for 1.5 minutes, and then rinsed in 900 mL of separately prepared 4 dH hard water at 25° C. at 120 rpm for 3 minutes at 25° C. This operation (dehydration and rinsing) was repeated twice. Drying process: After the rinsing step, the washed items were dehydrated for 1.5 minutes, and then only the cotton cloth (1) was taken out, sandwiched between two cotton cloths, and dried with an iron. The reflectance (Z value) of the cotton fabric (1) that had been subjected to the above-mentioned washing treatment and the cotton fabric (1) before the washing treatment was measured using a reflectometer (spectrophotometer, product name: SE6000, manufactured by Nippon Denshoku Industries Co., Ltd.), and the anti-redeposition rate was calculated using the following formula. Redeposition prevention rate = (Z value of cotton cloth (1) after washing) / (Z value of cotton cloth (1) before washing) x 100

[0045] <Biodegradability test> The biodegradability test of the modified products obtained in the examples was carried out in accordance with OECD301F. Preparation of medium: Stock medium solutions A to D were prepared by the following method. Solution A: 0.850 g of potassium dihydrogen phosphate (KH2PO4), 2.175 g of dipotassium hydrogen phosphate (K2HPO4), 6.7217 g of disodium hydrogen phosphate 12-hydrate (Na2HPO4 12H2O), and 0.050 g of ammonium chloride (NH4Cl) were weighed into a 50 ml sample bottle, dissolved in an appropriate amount of water, transferred to a 100 ml measuring flask, and then water was added up to the mark. Solution B: 3.640 g of calcium chloride dihydrate (CaCl2·2H2O) was dissolved in an appropriate amount of water and transferred to a 100 ml measuring flask, after which water was added up to the mark. Solution C: 2.250 g of magnesium sulfate heptahydrate (MgSO4·7H2O) was dissolved in an appropriate amount of water and transferred to a 100 ml measuring flask, after which water was added up to the mark. Solution D: 0.025 g of iron(III) chloride hexahydrate (FeCl3·6H2O) was dissolved in an appropriate amount of water and transferred to a 100 ml measuring flask, after which water was added up to the mark. The above stock medium solutions A to D were adjusted to 25°C, and 10 ml of A was placed in a 1L measuring flask using a whole pipette and diluted with approximately 800 ml of water. Then, 1 ml each of B, C, and D was added using a whole pipette and diluted to the mark with water adjusted to 25°C. Multiple portions of the above medium were prepared according to the amount required for the test. The prepared medium was transferred to a 5L beaker, mixed, and bubbled for more than 1 hour while stirring. Preparation of sludge solution: The sludge used in the biodegradability test was obtained from Minami Suita Sewage Treatment Plant. First, the concentration of the obtained sludge was measured by the following method. The obtained sludge was bubbled while stirring, 5 ml was taken using a whole pipette, and suction filtered using filter paper. Five sheets of filter paper on which the sludge was collected in this way were prepared, and after drying at 105°C for 1 hour in a dryer, the concentration of the sludge was calculated from the average weight loss of the five sheets. This sludge was diluted with the medium prepared above to prepare a 1000 ppm sludge solution. Preparation of denaturant solution: The modified product obtained in each Example was diluted with pure water to obtain a 2% by mass aqueous solution of the modified product. As a standard substance, sodium benzoate was diluted with pure water to obtain a 2% by mass aqueous solution of sodium benzoate. BOD Testing: A pressure sensor type BOD meter was used to measure the BOD. 144.75 g of the medium prepared above was weighed into a flask, and 0.75 g of a 2% denatured solution was added. For the blank measurement, 0.75 g of pure water was added, and for the standard measurement, 0.75 g of a 2% sodium benzoate solution was added. The pH of the solution was then measured, and the pH was adjusted with a 0.1 M hydrochloric acid solution so that the pH value of the solution was 7.4 ± 0.2. Then, 4.5 ml of 1000 ppm sludge solution was added to make the test solution. After placing a stirrer in the flask, 1.8 g of CO2 absorbent (Yabasil lime) was placed in the CO2 absorbent holder, set it, and a BOD sensor was attached. The flask with the BOD sensor attached was stirred in a thermostatic bath at 22 ° C, and the BOD value was calculated from the pressure sensor. Calculation of decomposition rate: The theoretical oxygen demand (ppm) of the modified substance was calculated, and the decomposition rate was calculated from the difference between the BOD value of the blank measurement and the BOD value measured using the modified substance. The decomposition rate 28 days after the start of the test was calculated as the biodegradation rate using the following formula. Decomposition rate (%) = (biochemical oxygen consumption from modified substance) / (theoretical oxygen demand of modified substance) x 100

[0046] [Table 1]

Claims

1. A modified polysaccharide in which a hydroxyl group of a polysaccharide is esterified (substituted) with a carboxylic acid having two or more carboxyl groups or a salt thereof, The modified polysaccharide has a degree of substitution (DS) per monosaccharide unit with the carboxylic acid or a salt thereof of 1 or more.

2. The modified polysaccharide of claim 1 , wherein the polysaccharide is starch and / or cellulose.

3. The modified polysaccharide according to claim 1 or 2, wherein the carboxylic acid is an anhydride of a dicarboxylic acid.

4. A detergent composition comprising the modified polysaccharide according to claim 1 or 2.

Images