JP5480574B2 - Anti-darkening stain - Google Patents

Description

  The present invention relates to a dark stain preventing agent having good biodegradability and excellent ability to prevent re-contamination of wrinkle stains, and a cleaning composition containing the same.

Water-soluble polymer drugs such as polycarboxylic acids have functions such as particle dispersion / stabilization, aggregation, viscosity adjustment, and adhesion, and are applied in various fields. However, since many water-soluble polymer materials are difficult to recover after use, they are required to be biodegradable in order to reduce the environmental burden.
On the other hand, in washing clothes, it has long been known that it is difficult to wash solid stains with scissors, etc., and in recent years, with the progress of water-saving in washing machines, the items to be washed are darkened every time they are washed. The problem is getting bigger.
The main factor that the object to be cleaned becomes darker every time washing is performed is a phenomenon in which wrinkle stains detached from the object to be cleaned in the cleaning process reattach to the object to be cleaned in the washing water. When the amount of washing water decreases, the concentration of dirt in the washing water increases, so that redeposition of wrinkle dirt is likely to occur. On the other hand, if the amount of washing water decreases, the concentration of the cleaning agent and dispersant in the washing liquid increases, and the anti-reattachment effect by the cleaning agent and the like is improved. Since redeposition is large, “darkening” of the object to be cleaned is promoted.
Although it is preferable to reduce washing water from the viewpoints of reducing environmental impact and improving economic efficiency, it is difficult to improve with the washing machine itself because the “darkness” of the object to be washed is due to the small amount of water used. is there. Therefore, there is a strong demand for a cleaning composition that not only exhibits high cleaning power even in a cleaning system that uses a small amount of water, but can suppress darkening of the object to be cleaned.

Conventionally, as a technique for preventing redeposition of dirt, a detergent builder composition containing a dispersion / anti-deposition agent such as a polymer (see Patent Document 1), a nonionic surfactant, a smectite clay mineral, and a granular containing an oil-absorbing carrier Nonionic detergent composition (see Patent Document 2), detergent composition comprising a soil release agent such as sebum soil comprising a graft copolymer in which an ionic polymer main chain and an ionic polymer side chain of the opposite charge are linked to each other (See Patent Document 3) and the like are known.
However, in Patent Documents 1 to 3, the effect of preventing dark stains is not sufficient.
Patent Document 4 discloses a detergent composition containing a copolymer having a structural unit derived from N-vinylpyrrolidone and a structural unit derived from vinyl acetate for the purpose of preventing re-contamination such as wrinkles. However, this copolymer has a problem that it cannot be produced from renewable natural raw materials.

On the other hand, as a method for producing oxidized cellulose, Patent Document 5 discloses a method for producing a substantially completely oxidized cellulose derivative in which mercerized cellulose or regenerated cellulose is oxidized in the presence of an N-oxyl compound.
However, this completely oxidized cellulose is a highly crystalline oxidized cellulose having a type II crystal structure, and its preparation requires a non-aqueous solvent, metal, etc., which is disadvantageous in terms of cost and environment. is there.
Patent Document 6 discloses a method in which lignocellulose is treated with an aqueous medium containing a nitroxy radical derivative, an alkali bromide, and an oxidizing agent to obtain oxidized cellulose nanofibers. Patent Document 7 discloses a carboxyl group. A gas barrier material containing cellulose fibers having a content of 0.1 to 2 mmol / g and an average fiber diameter of 200 nm or less is disclosed.
However, the oxidation degree of the oxidized cellulose obtained in Patent Documents 6 and 7 is about 35% or less, and even if these are added to the cleaning agent, the effect of preventing the reattachment of wrinkles is not sufficient.

Japanese Laid-Open Patent Publication No. Sho 62-253694 Japanese Patent Laid-Open No. 9-87691 JP 2001-131588 A JP 2008-208187 A JP-A-10-251302 JP 2008-308802 A JP 2009-57552 A

  An object of the present invention is to provide a dark stain preventive agent that has good biodegradability and can prevent re-contamination of wrinkle stains, and a cleaning composition containing the same.

The above prior art is insufficient for preventing redeposition of wrinkle stains in wash water whose stain concentration has increased due to a small amount of wash water and for reducing the environmental load.
In order to prevent darkening in washing, a cleaning agent having high anti-reattachment properties for hydrophobic fine particles such as wrinkles is required.
The present inventors have found that polyuronic acid having an oxidation degree of 50% or more obtained by oxidizing cellulose having a cellulose I-type crystallinity of 10% or more has good biodegradability and has excellent blackening stain prevention performance. I found out.
That is, the present invention provides the following (1) and (2).
(1) A dark stain preventing agent containing polyuronic acid having an oxidation degree of 50% or more, obtained by oxidizing cellulose cellulose having a crystallinity of 10% or more.
(2) A cleaning composition containing the dark stain preventing agent of (1).

  According to the present invention, there are provided a dark stain preventive agent having good biodegradability and capable of preventing recontamination of wrinkle stains removed from clothes by mechanical force during washing, and a cleaning composition containing the same. Can do.

The dark stain preventing agent of the present invention is characterized by containing polyuronic acid having an oxidation degree of 50% or more obtained by oxidizing powdered cellulose having a cellulose I-type crystallinity of 10% or more. Moreover, the cleaning composition of the present invention is characterized by containing the above-mentioned darkening stain preventing agent.
Hereinafter, polyuronic acid, raw material cellulose and the like used in the present invention will be described.

[Polyuronic acid]
The polyuronic acid in the present invention is a polymer in which an alkali metal salt of uronic acid such as D-glucuronic acid or D-galacturonic acid is linked to a sugar unit by a glycosidic bond, and is typically represented by the following structural formula (1). The degree of oxidation is 50% or more.

In the structural formula (1), X represents hydrogen or an alkali metal. When X is hydrogen or sodium, the polyuronic acid (salt) represented by the structural formula (1) exhibits a solubility of 10% or more in distilled water at 25 ° C.
M in the structural formula (1) indicates the molar fraction of D-glucuronic acid (salt) units in polyuronic acid (salt), and is synonymous with the degree of oxidation of polyuronic acid. The molar fraction m, that is, the degree of oxidation of polyuronic acid is 50% or more, preferably 60% or more, more preferably 65% or more, and further preferably 70 to 100%. By setting the molar fraction m to 50% or more, it becomes possible to stably disperse in the washing liquid by the charge repulsion of the polyuronic acid adsorbed on the soot particles. When the degree of oxidation (m) of the polyuronic acid salt is lower, a part insoluble in water may be produced, but the dark dirt prevention performance is exhibited including that part.
N in the structural formula (1) indicates a mole fraction of saccharide units in the polyuronic acid salt, and n is less than 50%, preferably less than 40%, more preferably less than 35%, still more preferably from 30 to 0%.
From these viewpoints, the molar fraction ratio (m / n) between the uronic acid salt unit m and the sugar unit n is 50-100 / 50-0, preferably 60-100 / 40-0, more preferably 65- It is 100 / 35-0, More preferably, it is 70-100 / 30-0.

Here, the oxidation degree of polyuronic acid is calculated as the ratio of the number of equivalents of the basic compound used for neutralization to the number of equivalents of carboxy groups in the polyuronic acid unit. Specifically, it is a value determined by the following formula (2) from the amount of carboxylic acid per unit weight of polyuronic acid salt measured by the titration method described in the examples.
Oxidation degree (%) = [(162.1 × A) / (1-14.0 × A)] × 100 (2)
Here, A is the amount of carboxylic acid (mol / g) determined by titration.
Examples of the basic compound used for neutralization include alkali metal or alkaline earth metal hydroxides such as sodium hydroxide, potassium hydroxide, and magnesium hydroxide, ammonia, and amine compounds.

The weight average molecular weight of polyuronic acid is preferably 10,000 to 180,000, more preferably 12,000 to 120,000, and still more preferably 13,000 to 100,000. If the weight average molecular weight is 10,000 or more, the fine particles removed from the garment can be sufficiently dispersed in the washing liquid and effectively prevent the moth particles from reattaching to the garment. it can. In addition, when the weight average molecular weight is 18,000 or less, it is possible to prevent polyuronic acids adsorbed on the surface of the soot fine particles from being bonded to each other between the soot fine particles to form aggregates of the soot fine particles. Increase in viscosity at the time of blending can be suppressed.
The degree of oxidation and the weight average molecular weight of polyuronic acid can be appropriately adjusted according to the reaction conditions such as the type of raw material polysaccharide and the amount of oxidizing agent, and can change the dirt cleaning performance.

(Raw cellulose)
The cellulose used as a raw material for producing polyuronic acid may be powdered cellulose having a cellulose I-type crystallinity of 10% or more, and the type and molecular weight are not particularly limited. The cellulose type I crystallinity of the raw material cellulose is preferably 25% or more, more preferably 30% or more. When oxidized cellulose is produced using cellulose having a high degree of crystallinity, a part insoluble in water is produced, and by including this part insoluble in water, a high dark stain prevention performance is exhibited.
Several crystal structures are known for cellulose, and the degree of crystallinity is generally calculated from the ratio of crystal parts to the total amount of crystal parts and amorphous parts.
In the present invention, “cellulose type I crystallinity” means type I crystallinity derived from the crystal structure of natural cellulose, and is calculated by the Segal method from the diffraction intensity value by the powder X-ray crystal diffraction spectrum method. It is defined by the following calculation formula (3).
Cellulose type I crystallinity (%) = [(I _22.6 -I _18.5 ) / I _22.6 ] × 100 (3)
Wherein, I _22.6, the lattice plane in X-ray diffraction (002 plane) indicates the diffraction intensity of the (diffraction angle 2θ = 22.6 °), I _18.5 is amorphous portion (angle of diffraction 2 [Theta] = 18.5 °) The diffraction intensity is shown. ]

As the raw material cellulose, pulp with high crystallinity can be used as it is, but the oxidation reaction of the crystalline part is difficult to proceed, which is not preferable from the viewpoint of efficiently obtaining polyuronic acid. According to the calculation formula (1), the crystallinity of powder cellulose that is generally known is so-called crystalline cellulose included in a range of approximately 60 to 80%. Therefore, it is preferable to use powdered cellulose whose crystallinity is lowered by mechanochemical treatment or the like. At this time, it is necessary to prevent the crystallinity from being lowered excessively. That is, since cellulose having a large number of non-crystallized portions is less likely to exhibit darkening contamination prevention performance, the cellulose type I crystallinity of raw material cellulose needs to be 10% or more, preferably 10 to 75%, more preferably 15 to 73. %, More preferably 30 to 70%.
Moreover, 150 or more are preferable, as for the polymerization degree of raw material cellulose, 200 or more are more preferable, and 300 or more are still more preferable.
Such cellulose powder with reduced cellulose I-type crystallinity can be easily prepared from sheet-like or roll-like pulp with high cellulose purity obtained as a general-purpose raw material. There is no particular limitation on the method for preparing the powdered cellulose having a reduced crystallinity. For example, methods described in JP-A-62-236801, JP-A-2003-64184, JP-A-2004-331918 and the like can be mentioned. Among these, it is more preferable to use powdered cellulose whose crystallinity is lowered by mechanochemical treatment.

(Mechanochemical treatment)
A particularly preferred method for producing powdered cellulose by mechanochemical treatment includes, for example, a method in which chip-like pulp obtained by roughly pulverizing sheet pulp is treated with an extruder and further treated with a ball mill.
Examples of the extruder used in this method include a single-screw or twin-screw extruder, preferably a twin-screw extruder. From the viewpoint of applying a strong compressive shear force, a so-called kneading is applied to any part of the screw. A thing provided with a disk part is preferred.
The kneading disc portion is composed of a plurality of kneading discs, which are combined while being shifted at a constant phase. For example, a combination of 3 to 20 kneading disks, preferably 6 to 16 kneading disks, which are staggered at a phase of 90 °. The kneading disk portion can be continuously processed while applying a very strong shearing force by forcibly passing chip-like pulp through the narrow gap as the screw rotates. As a shear rate in an extruder process, 600-3000 sec < ^-1 > is preferable and 6000-2000 sec < ^-1 > is more preferable.
Although there is no restriction | limiting in particular as a processing method using an extruder, The method of throwing a chip-form pulp into an extruder and processing continuously is preferable.

As the ball mill, a known vibration ball mill, medium stirring mill, rolling ball mill, planetary ball mill, or the like can be used.
There is no restriction | limiting in particular in the material of the ball | bowl used as a medium, For example, iron, stainless steel, an alumina, a zirconia etc. are mentioned. The outer diameter of the ball is preferably 0.1 to 100 mm, more preferably 1 to 50 mm, from the viewpoint of efficiently amorphizing cellulose. As a medium, besides a ball, a rod-shaped or tube-shaped medium can be used.
In the ball mill treatment, the treatment is preferably performed at a temperature of preferably 250 ° C. or less, more preferably 5 to 200 ° C., in order to minimize denaturation and deterioration due to generated heat.

[Production of polyuronic acid]
The polyuronic acid used in the present invention is obtained by dissolving or dispersing powdered cellulose having a cellulose I-type crystallinity of 10% or more in a solvent, and performing an oxidation reaction in the presence of a catalyst and, if necessary, a co-oxidant or a co-catalyst. Can be manufactured. Here, the oxidation reaction refers to glucuronic acid having a carboxy group (expressed by the above structural formula (1)) by selectively oxidizing a primary hydroxyl group of a glucose unit which is a constituent component of cellulose, that is, a primary hydroxyl group of C6 position. This is a reaction for generating a left portion.
Examples of the selective oxidation reaction of the primary hydroxyl group include an oxidation reaction with oxygen using a platinum catalyst, an oxidation reaction with nitrogen oxides, an oxidation reaction with nitric acid, and an oxidation reaction with an N-oxyl compound. Among these, in view of high selectivity of the reaction, homogeneity, and smooth progress of the oxidation reaction under milder conditions, an N-oxyl compound is used as a catalyst in the presence thereof, and if necessary, a co-oxidant. It is preferable to produce polyuronic acid by carrying out an oxidation reaction using a cocatalyst.

(N-oxyl compound)
The N-oxyl compound is a hindered amine N-oxide, particularly a hindered amine N-oxide having a bulky group at the α-position of the amino group. Examples of N-oxyl compounds include 2,2,6,6-tetraalkylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetraalkylpiperidine-1-oxyl, 4-alkoxy-2,2 Di-tertiary alkyl nitroxyl compounds such as 6,6-tetraalkylpiperidine-1-oxyl. Among these, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2,2,6 , 6-Tetramethylpiperidine-1-oxyl is preferred, and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) is more preferred.
In the oxidation reaction using TEMPO as the N-oxyl compound, it is considered that the oxoammonium moiety, which is an oxidation active species of the nitroxy radical, functions as an oxidizing agent.
The amount of the N-oxyl compound in the reaction system may be a catalytic amount, and is preferably 0.001 to 5% by mass, more preferably 0.1 to 4% by mass, and more preferably 0.1 to 4% by mass, based on the low crystalline powdery cellulose. Preferably it is 0.5-3 mass%.

(Co-oxidizer and cocatalyst)
Examples of the co-oxidant include oxygen or air, peroxide, halogen, hypohalous acid, halous acid, perhalogen acid or salts thereof, halogen oxide, nitrogen oxide and the like.
Examples of the cocatalyst include bromides such as sodium bromide and potassium bromide, and iodides such as sodium iodide and potassium iodide.
The amount of the co-oxidant and the co-catalyst is not particularly limited as long as it is an effective amount capable of exhibiting these functions.

(Reaction conditions)
The temperature of the oxidation reaction is preferably 50 ° C. or less, more preferably 40 ° C. or less, further preferably 20 ° C. or less, and the lower limit is preferably from the viewpoint of reaction selectivity and side reaction suppression. Is −5 ° C. or higher.
The pH of the reaction system is preferably matched to the properties of the cooxidant. For example, in the case of sodium hypochlorite, the pH of the reaction system is preferably on the alkali side.
The oxidation reaction in the present invention is preferably carried out by dispersing low crystalline powdered cellulose in water or an organic solvent. Examples of the organic solvent include alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, N, N-dimethylformamide, and dimethyl sulfoxide. Among these, from the viewpoint of reducing environmental burden, it is more preferable to carry out the oxidation reaction by dispersing in water or an aqueous medium containing water as a main component and containing an organic solvent. The aqueous medium can be water alone or a mixture of water and two or more organic solvents.
In the production of polyuronic acid salts, residual N-oxyl compounds such as TEMPO used as a catalyst and salt by-products are likely to occur. Therefore, in order to obtain a highly pure polyuronic acid salt, reprecipitation into methanol, ethanol, acetone, etc., extraction of N-oxyl compounds into a solvent insoluble in water, ion exchange of salts, purification by dialysis, etc. Preferably it is done. As the purification method, an optimum method can be adopted depending on the kind of solvent in the oxidation reaction, the degree of oxidation of the product, and the degree of purification.

[Cleaning composition]
The cleaning composition of the present invention contains an anti-darkening agent containing polyuronic acid having a degree of oxidation of 50% or more obtained by oxidizing cellulose cellulose having a crystallinity of 10% or more. Characteristically, preferably further containing a surfactant. When the darkening stain preventing agent containing the polyuronic acid and the surfactant are used in combination, the effect of preventing stain recontamination is enhanced.
From the viewpoint of cleaning performance, the content of the polyuronic acid in the cleaning composition is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, and even more preferably 1.5 to 10% by mass. preferable. The content of the surfactant in the cleaning composition is preferably 5 to 60% by mass, more preferably 10 to 40% by mass, and more preferably 20 to 30% by mass from the viewpoint of effectively expressing cleaning performance and re-contamination prevention. % Is more preferable.

Examples of the surfactant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant.
Examples of the anionic surfactant include alkylbenzene sulfonate, alkylnaphthalene sulfonate, dialkyl sulfosuccinate, α-olefin sulfonate, higher alcohol sulfate, alkyl ether sulfate, polyoxyethylene alkyl Phenyl ether sulfate, fatty acid alkylolamide sulfate ester, alkyl ether phosphate ester salt, alkyl phosphate ester salt, alkyl ether carboxylate, N-acyl amino acid salt, fatty acid soap and the like are preferably used.
Among the above anionic surfactants, linear alkyl benzene sulfonates, alkyl sulfate esters, and polyoxyalkylene alkyl ether sulfates are preferable, and linear alkyl benzene sulfonate sodium having an alkyl chain having 10 to 18 carbon atoms is preferable. More preferred.

As the cationic surfactant, aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts and the like are preferably used.
Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene block polymer, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene glycerin fatty acid ester, polyoxyethylene Castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyethylene glycol fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, higher fatty acid alkanolamide or its alkylene oxide adduct, polyoxyethylene alkylamine , Alkylamine oxide and the like are preferably used.
The nonionic surfactant has good hard water resistance and excellent detergency for oily dirt such as sebum dirt, and preferred examples thereof include an alkyl group having an average carbon number of 10 to 20, preferably Examples thereof include polyoxyethylene alkyl ethers having 12 to 18, particularly preferably 12 to 14, and an average added mole number of ethylene oxide of 6 to 14, preferably 6 to 10.
As the amphoteric surfactant, for example, carboxybetaine type compounds, aminocarboxylates, imidazolinium betaines and the like are preferably used.

As the surfactant, an anionic surfactant and a nonionic surfactant are preferably used as the main surfactant.
The content of the anionic surfactant in the cleaning composition is preferably 5% by mass or more, more preferably 7% by mass or more, and more preferably 9% by mass from the viewpoint of detergency against hydrophobic solid particle dirt such as wrinkles. The above is more preferable. Moreover, from a viewpoint of powder physical properties, 40 mass% or less is preferable, 35 mass% or less is more preferable, 30 mass% or less is more preferable, and 26 mass% or less is still more preferable.
The content of the nonionic surfactant in the cleaning composition is preferably 1 to 15% by mass and more preferably 5 to 15% by mass from the viewpoint of foamability and rinsability.

In producing the cleaning composition of the present invention, various detergent components used in ordinary cleaning compositions can be blended in addition to the dark stain preventing agent and surfactant of the present invention.
Detergent components used include, for example, alkali agents, sequestering agents, other polymers, other additives, bleaching agents (percarbonate, perborate, etc.), bleach activators, recontamination Examples thereof include inhibitors (carboxymethyl cellulose and the like), softening agents, reducing agents (sulfite and the like), fluorescent whitening agents, antifoaming agents (silicone and the like), enzymes such as cellulase and protease, dyes and fragrances.
As the alkali agent, a known alkali agent can be used from the viewpoint of detergency. For example, alkali metal carbonates such as sodium carbonate collectively called dense ash and light ash, and amorphous alkali metal silicates such as JIS No. 1, No. 2 and No. 3 sodium silicate, crystalline alkali metal silicates, etc. Examples include alkali metal salts. From the viewpoint of increasing the detergency against oil stains such as sebum, the content of the alkaline agent in the cleaning composition is preferably 1 to 40% by mass, and more preferably 5 to 30% by mass or more.
Examples of the sequestering agent include crystalline aluminosilicate, crystalline sodium silicate, acrylic acid polymer, acrylic acid-maleic acid copolymer, sodium tripolyphosphate, ethylenediaminetetraacetic acid, and methylglycine diacetic acid.
Examples of other polymers include homopolymers or copolymer carboxylic acid polymers such as acrylic acid, methacrylic acid, and itaconic acid having a weight average molecular weight of 3000 to 20,000, and a weight average molecular weight of 1,000 to 20,000. Examples include polyethylene glycol and carboxymethyl cellulose.
Said surfactant and detergent component can be used individually or in combination of 2 or more types as appropriate.
Although there is no limitation in particular in the use of the cleaning composition of this invention, it can use especially suitably as a cleaning composition for textiles, such as a yarn bundle, a fabric, and clothing.

In the following production examples, examples and comparative examples, “%” is “% by mass” unless otherwise specified. In addition, the measurement of the polymerization degree and crystallinity degree of the low crystalline cellulose powder of a raw material, the measurement of the weight average molecular weight and oxidation degree of a polyuronic acid salt, and evaluation of biodegradability were performed with the following method.
In addition, the carbon black recontamination prevention performance of the polyuronic acid sodium salt obtained in Examples and Comparative Examples was evaluated by the following method.

<Measurement of degree of polymerization of powdered cellulose>
The degree of polymerization of powdered cellulose was measured by the copper ammonia method described in ISO-4312.
<Calculation of cellulose I type crystallinity>
Using a “Rigaku RINT 2500VC X-RAY diffractometer” manufactured by Rigaku Corporation, the cellulose I type crystallinity was calculated from the peak intensity of the diffraction spectrum measured under the following conditions by the above formula (3).
X-ray light source: Cu / Kα-radiation, tube voltage: 40 kV, tube current: 120 mA
Measurement range: 2θ = 5-45 °,
Measurement sample: Prepared by compressing pellets with an area of 320 mm ² × thickness 1 mm X-ray scanning speed: 10 ° / min

<Measurement of weight average molecular weight of polyuronic acid>
It measured on condition of the following using gel permeation chromatography. The portion not dissolved in water was removed using a 0.45 μm filter, and only the portion dissolved in water was measured.
Column: Tosoh Corporation G4000PWXL + G2500PWXL
Eluent: 0.2M phosphate buffer / acetonitrile (volume ratio) = 9/1
Measurement temperature: 40 ° C., flow rate: 1.0 mL / min, detector: UV or RI
Standard polymer: Pullulan

<Measurement of oxidation degree of polyuronic acid>
50 g of a 2% aqueous solution or aqueous dispersion of sodium polyuronic acid produced was prepared, and the pH was adjusted to 1 or less with 6N hydrochloric acid. This acidic aqueous solution was poured into 500 mL of ethanol, and the resulting precipitate was recovered and washed several times with ethanol. 0.1 g of the resulting polyuronic acid is precisely weighed, dissolved or dispersed in 30 mL of ion exchange water, titrated with 0.1N aqueous sodium hydroxide solution using phenolphthalein as an indicator, and the amount of carboxylic acid per unit weight of polyuronic acid salt Asked. Furthermore, from the amount of carboxylic acid, the degree of oxidation was determined by the following formula (2).
Oxidation degree (%) = [(162.1 × A) / (1-14.0 × A)] × 100 (2)
Here, A is the amount of carboxylic acid (mol / g) determined by titration.
The degree of oxidation of potato starch and the degree of carboxyl methylation of carboxymethyl cellulose were also measured in the same manner.

<Evaluation of biodegradability>
A 3 L beaker was charged with 50 mg-carbon / L (about 100 mg / L) of polymer and 200 mg / L of treatment site sludge, and the test was conducted at 25 ± 1 ° C. while bubbling and stirring air. On the 28th day from the start of the test, a sample was collected and filtered through a 0.2 μm filter, and the dissolved organic carbon concentration (DOC) was measured.
The biodegradation rate (%) was determined by the ratio with the DOC at the start of the test.

<Evaluation of carbon black recontamination prevention performance>
The cleaning composition shown below was prepared, the cleaning test of the carbon black dirty cloth was performed by the following method, and the polymers of Examples and Comparative Examples were blended with the cleaning agent not blended with a polymer such as polyuronic acid. The increase rate (%) of prevention of recontamination of the cleaning composition was calculated, and the recontamination prevention performance was evaluated.
(Composition of cleaning composition)
Polyoxyethylene (average addition mole number of ethylene oxide 2.5) alkyl (carbon number 12-14) ether sodium sulfate: 25%
Polyoxyethylene (average added mole number of ethylene oxide 7) alkyl (carbon number 12-14) ether: 15%
Polymer such as sodium salt of polyuronic acid: 6%, water: balance (test cloth)
Cotton knitted fabric (fluorescent dye-undyed fabric) was obtained from Tanigami Shoten Co., Ltd.
(Carbon black recontamination prevention test)
For the evaluation of the effect of preventing recontamination, a targotometer was used.
The above detergent composition was dissolved in 100 mL of 72 mg / L (calculated in terms of CaCO ₃ ) of calcium hard water to prepare 0.15%. Next, 0.13 g of carbon black is put into the detergent solution, and is irradiated with ultrasonic waves for 15 minutes using a bathtub of an ultrasonic oscillator (made by Kokusai Electric Eltech Co., Ltd., model U0600PB-Y), dispersed, and tergotometer Moved to.
Three kinds of treated cloths each having a size of 4 × 5 cm, each of which is a set of 15 pieces in a set of 5 pieces are put into a solution in a targotometer, and the rotation speed is 100 times / minute at 25 ° C. for 30 minutes. Then, it was rotated with a tartometer and washed. After rinsing with 5 L of tap water, an iron press treatment was performed. Next, the reflectance at 550 nm of the raw cloth before washing and the recontamination test cloth was measured with a spectrocolor difference meter SE2000 manufactured by Nippon Denshoku Industries Co., Ltd. The recontamination prevention rate (%) and the recontamination prevention increase from the following equations The rate (%) was calculated.
Recontamination prevention rate (%) = [reflectance after washing / reflectance of base fabric] × 100
Increase rate of prevention of recontamination (%) = [(recontamination prevention rate when polymer is added−recontamination prevention rate when polymer is not added) / recontamination prevention rate when polymer is not added] × 100

Production Example 1 (Production of low crystalline powdered cellulose)
A wood pulp sheet (manufactured by Boleguard, pulp sheet, crystallinity 74%) was shredded (manufactured by Meiko Shokai, "MSX2000-IVP440F") to form a chip.
Next, the obtained chip-like pulp was charged at 2 kg / hr into a twin-screw extruder ("EA-20" manufactured by Suehiro EPM Co., Ltd.) equipped with a kneading disk at the center of the screw, and a shear rate of 660 sec. ^-1 and powdered by one pass treatment while flowing cooling water from the outside under the condition of screw rotation speed of 300 rpm.
Next, the powdered cellulose thus obtained was mixed into a batch-type medium stirring ball mill (Igarashi Machine Co., Ltd., “Sand Grinder 6TSG-1 / 4”, ball filling rate 25%, zirconia balls (5 mmφ)). 80 g of cellulose was added. While passing cooling water through the container jacket, pulverization was performed at a stirring rotational speed of 2000 rpm for 15 minutes to obtain low crystalline powdery cellulose (crystallinity 32%, polymerization degree 574, average particle size 66 μm).

Production Examples 2-3 (Production of Amorphized Powdered Cellulose)
Except for changing the treatment time in the ball mill treatment, in the same manner as in Production Example 1, non-crystallized powdered cellulose having a crystallinity of 0% and a polymerization degree of 62 (Production Example 2), a crystallinity of 0% and a polymerization degree of 31 Amorphized powdered cellulose (Production Example 3) was produced.
Production Examples 4 to 6 (Production of mixed powder cellulose)
Powdered cellulose (manufactured by Nippon Paper Chemical Co., Ltd., trade name: KC Flock 400G (registered trademark), crystallinity 70%, polymerization degree 250) and the non-crystallized powdered cellulose obtained in Production Example 2 (Weight ratio) = 71/29 (Production Example 4) or 60/40 (Production Example 5) or 80/20 (Production Example 6) were mixed to produce mixed powdered celluloses A to C.

Example 1 (Production and evaluation of polyuronic acid salt)
A 500 mL separable flask equipped with a pH meter is charged with 5 g of the low crystalline powder cellulose (polymerization degree 574) obtained in Production Example 1 and 95 g of ion-exchanged water, and stirred at a rotation speed of 200 rpm using a football-type stirrer. Then, the amorphous cellulose powder was dispersed. An aqueous solution prepared by dissolving 0.095 g of 2,2,6,6-tetramethyl-1-piperidine-N-oxyl (TEMPO) and 1.25 g of sodium bromide in 150 g of ion-exchanged water was added to the powdered cellulose dispersion. Stirring was continued under ice cooling. When the temperature of the reaction solution became 5 ° C. or lower, 15 g of an aqueous sodium hypochlorite solution was added to the amorphous cellulose dispersion.
As the oxidation reaction progresses, the pH decreases, so 0.5N NaOH (61.7 mL) was gradually added using a microtube pump in order to bring the pH of the amorphous cellulose dispersion to around 10.8. . Furthermore, 40 g of sodium hypochlorite aqueous solution (effective chlorine concentration 5%) was added over 1 hour, and 0.5 N NaOH was added to adjust the pH to around 10.8.
The reaction-terminated liquid was poured into 3 L of ethanol to precipitate polyuronic acid sodium salt. The precipitate was collected by filtration, washed with a solvent of acetone / water (volume ratio) = 7/1, further washed with acetone, and then dried at 40 ° C. to obtain 6 g of slightly yellow sodium salt of polyuronic acid. .
The degree of oxidation of this polyuronic acid was 68%, the weight average molecular weight was 72,600, and the biodegradation rate was 94%.
Table 1 shows the results of calculating the increase rate (%) of the recontamination prevention rate of the obtained polyuronic acid salt and evaluating the carbon black (CB) recontamination prevention performance.

Example 2
In Example 1, instead of the low crystalline powdered cellulose obtained in Production Example 1, highly crystalline powdered cellulose (manufactured by Nippon Paper Chemical Co., Ltd., trade name: KC Flock 400G (registered trademark), crystallinity 70% The sodium salt of polyuronic acid having an oxidation degree of 61% was produced in the same manner as in Example 1 except that the polymerization degree 679) was used. The results are shown in Table 1.
Examples 3-5
In Example 1, in place of the low crystalline powdered cellulose obtained in Production Example 1, mixed powdered celluloses A to C obtained in Production Examples 4 to 6 were used in the same manner as in Example 1, Sodium salt of polyuronic acid having a degree of oxidation of 70% (Example 3), sodium salt of polyuronic acid having a degree of oxidation of 100% and a weight average molecular weight of 13,900 (Example 4), degree of oxidation of 74% and a weight average molecular weight of 17 , 200 polyuronic acid sodium salt (Example 5). The results are shown in Table 1.

Comparative Examples 1-2
In Example 1, in place of the low crystalline powdered cellulose obtained in Production Example 1, the amorphous cellulose powder obtained in Production Example 2 or 3 was used in the same manner as in Example 1, except that the oxidation was performed. A polyuronic acid sodium salt having a degree of 89% and a weight average molecular weight of 16,800 (Comparative Example 1) and a polyuronic acid sodium salt having a degree of oxidation of 91% and a weight average molecular weight of 13,900 (Comparative Example 2) were produced. The results are shown in Table 1.
Comparative Examples 3-4
In Example 1, the sodium shown in Table 1 was used, and 12 g of an aqueous sodium hypochlorite solution (effective chlorine concentration 5%) was used. A salt was produced. The results are shown in Table 1.
Comparative Example 5
In Example 1, instead of the low crystalline powder cellulose obtained in Production Example 1, oxidation was performed in the same manner as in Example 1 except that potato starch was used to produce oxidized starch. The results are shown in Table 1.
Comparative Example 6
Commercially available sodium carboxymethyl cellulose (CMC, manufactured by Nippon Paper Chemical Co., Ltd., trade name: Sunrose (registered trademark) APP-84, biodegradation rate: 74%) is used as it is to prevent carbon black (CB) recontamination. The evaluation results are shown in Table 1.
Comparative Example 7
Table 1 shows the results of evaluating the carbon black (CB) recontamination prevention performance using a commercially available sodium polyacrylate (trade name: Poise (registered trademark) 536, manufactured by Kao Corporation) as it is.

  From the results in Table 1, it can be seen that the sodium salt of polyuronic acid of the example is extremely superior in carbon black (CB) recontamination prevention performance as compared with the comparative example.

Claims (4)

An anti- darkening antifouling agent for preventing recontamination of dirt during washing , comprising polyuronic acid having an oxidation degree of 50% or more, obtained by oxidizing cellulose cellulose having a crystallinity of 10% or more.   The dark stain preventing agent according to claim 1, wherein the polyuronic acid is obtained by performing an oxidation reaction in the presence of an N-oxyl compound.   The blackening stain preventing agent according to claim 1 or 2, wherein the polyuronic acid is obtained by dispersing powdered cellulose in an aqueous medium and performing an oxidation reaction.   A cleaning composition containing the darkening stain preventing agent according to any one of claims 1 to 3.