JP2007070532A - Modified polyvinyl alcohol and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a modified polyvinyl alcohol having unsaturated double bonds derived from a specific monomer in a main chain of a molecule and its manufacturing method. <P>SOLUTION: This modified polyvinyl alcohol has an unsaturated double bond unit derived from a specific monomer in a main chain of the molecule, wherein Mw'/Mw, a relationship of the weight average molecular weight of a polymer component obtained by the ozonolysis treatment (Mw') to the weight average molecular weight of the modified polyvinyl alcohol (Mw), is 0.001-0.70. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a modified polyvinyl alcohol having a double bond derived from a specific monomer in the main chain and a method for producing the same.

As the polyvinyl alcohol having a reactive unsaturated double bond introduced into the molecule, the polyvinyl alcohol is post-modified with a reactive molecule containing a polymerizable double bond to form a polyvinyl alcohol side chain. After obtaining a product obtained by introducing an unsaturated double bond (for example, see Patent Document 1) or a polyvinyl ester copolymer having a protected ethylenically unsaturated double bond, the protection is removed. Known ones (for example, see Patent Document 2), those obtained by introducing an unsaturated double bond at the end of a polyvinyl alcohol molecule using an aldehyde as a chain transfer agent (for example, see Patent Document 3), etc. Yes.
JP 04-283749 A JP 2001-072720 A JP 2004-250695 A

An object of the present invention is to provide a modified polyvinyl alcohol in which unsaturated double bonds derived from a specific monomer are present on the main chain in the molecule on average, and a method for producing the same.

The above-mentioned problems can be solved by using polyvinyl alcohol obtained by polymerizing a specific monomer and causing a saponification reaction.

（式中、Ｘ１とＸ２は、炭素数１〜１２の低級アルキル基、水素原子または金属塩を表す。ｇは、０〜３の整数を表す。ｈは、０〜１２の整数を表す。Ｙ１は、カルボン酸、カルボン酸エステル、カルボン酸金属塩または水素原子を表す。）
（数２） Ｙ＝ａＸ＋ｂ
（式中、ａは−０．５０以下、ｂは０．７〜１．０の値を示す。） That is, the present invention is a modified polyvinyl alcohol having a bond unit represented by the general formula (Chemical Formula 9) in the molecular main chain, the weight average molecular weight (Mw) and the weight obtained by ozonolysis treatment. It is a modified polyvinyl alcohol having a relationship Mw ′ / Mw of 0.001 to 0.70 with the weight average molecular weight (Mw ′) of the combined component. In this case, Mw ′ / Mw value (Y) and 0.2% by mass, the total value (X) of the absorbance value at 280 nm and the absorbance value at 320 nm according to the ultraviolet absorption spectrum of the aqueous solution, methanol solution or aqueous methanol mixed solution. Is preferably 0.2% by mass or more, and the absorbance at 270 nm by an ultraviolet absorption spectrum of an aqueous solution, methanol solution or aqueous methanol mixed solution of 0.2% by mass is preferably 0.05 or more. The content of the modified polyvinyl alcohol is preferably 25% by mass or less.

(In formula, X1 and X2 represent a C1-C12 lower alkyl group, a hydrogen atom, or a metal salt. G represents the integer of 0-3. H represents the integer of 0-12. Y1. Represents a carboxylic acid, a carboxylic acid ester, a carboxylic acid metal salt or a hydrogen atom.)
(Equation 2) Y = aX + b
(In the formula, a represents −0.50 or less, and b represents a value of 0.7 to 1.0.)

A modified polyvinyl alcohol having an unsaturated double bond derived from a specific monomer on average in the main chain in the molecule is obtained.

The modified polyvinyl alcohol is obtained by copolymerizing a monomer having an ethylenically unsaturated double bond and a monomer having a vinyl ester unit, followed by saponification to obtain a carbonyl group-containing polyvinyl alcohol, washing and drying. An unsaturated double bond starting from a carboxyl group is introduced into the main chain on average.

The value of Mw ′ / Mw of the modified polyvinyl alcohol represents in which part the unsaturated double bond in the molecular main chain is present. When the modified polyvinyl alcohol is subjected to an ozonolysis treatment, the unsaturated double bond introduced into the main chain is selectively cleaved. For this reason, when unsaturated double bonds are present in the main chain in the modified polyvinyl alcohol molecule on average, the polymer obtained by ozonolysis treatment has no bias in weight average molecular weight and has a low molecular weight. Since the number of components increases, the value of Mw ′ / Mw also decreases. On the other hand, when unsaturated double bonds are present in a biased manner at the end or center of the main chain, the polymer component obtained by the ozonolysis treatment is a mixture of high and low molecular weight compounds, Since it has a molecular weight, the value of Mw ′ / Mw also increases.
The value of Mw ′ / Mw is not particularly limited, but the lower limit is 0.001 or more, preferably 0.10 or more, and the upper limit is 0.70 or less, preferably 0.50 or less.

The ozonolysis treatment is a treatment method described in Polymer, vol 22, 1721 (1981), Rubber Chemistry and Technology, vol. 59, 16 (1986), Macromolecules, vol. 16, 1925 (1983), or the like. In the present invention, in accordance with this treatment method, after the re-acetylated modified polyvinyl alcohol is dissolved in a solvent, ozone is bubbled to convert the unsaturated double bond to an ozonide, which is reduced with lithium aluminum hydride. A low molecular weight polymer component was obtained.
The weight average molecular weight before and after the ozonolysis treatment is a value measured using a RI (differential refraction) detector by size exclusion chromatography (SEC) measurement.
The re-acetylated modified polyvinyl alcohol is obtained by dissolving modified polyvinyl alcohol in a mixed solvent of pyrozine and acetic anhydride, reacting, diluting by adding acetone, adding ice water to precipitate, and vacuum drying. It is obtained.

（式中、Ｘ３とＸ４は、炭素数１〜１２の低級アルキル基または水素原子を表す。ｉは、０〜１２の整数を表す。Ｙ２は、カルボン酸、カルボン酸エステル、カルボン酸金属塩または水素原子を表す。）
これらモノマーとしては、例えば、マレイン酸ジメチル、マレイン酸ジエチル等がある。 As the monomer having an ethylenically unsaturated double bond, those represented by the general formula (Formula 10) can be suitably used.

(Wherein X3 and X4 represent a lower alkyl group having 1 to 12 carbon atoms or a hydrogen atom. I represents an integer of 0 to 12. Y2 represents a carboxylic acid, a carboxylic acid ester, a carboxylic acid metal salt, or Represents a hydrogen atom.)
Examples of these monomers include dimethyl maleate and diethyl maleate.

（式中、Ｘ５とＸ６は、炭素数１〜１２の低級アルキル基または水素原子を表す。ｊは、０〜１２の整数を表す。Ｙ３は、カルボン酸、カルボン酸エステル、カルボン酸金属塩または水素原子を表す。）
これらモノマーとしては、例えば、フマル酸ジメチル、フマル酸モノエチル、フマル酸ジエチル、シトラスコン酸ジメチル等がある。 Moreover, the monomer represented by the general formula (Chemical Formula 11) can also be suitably used.

(In the formula, X5 and X6 represent a lower alkyl group having 1 to 12 carbon atoms or a hydrogen atom. J represents an integer of 0 to 12. Y3 represents a carboxylic acid, a carboxylic acid ester, a carboxylic acid metal salt, or Represents a hydrogen atom.)
Examples of these monomers include dimethyl fumarate, monoethyl fumarate, diethyl fumarate, and dimethyl citrus acid.

（式中、ｋは、０〜１２の整数を表す。Ｙ４は、カルボン酸、カルボン酸エステル、カルボン酸金属塩または水素原子を表す。）
これらモノマーとしては、例えば、無水マレイン酸、無水シトラスコン酸等がある。 Moreover, the monomer represented by the general formula (Chemical Formula 12) can also be suitably used.

(In the formula, k represents an integer of 0 to 12. Y4 represents a carboxylic acid, a carboxylic acid ester, a carboxylic acid metal salt, or a hydrogen atom.)
These monomers include, for example, maleic anhydride, citraconic anhydride and the like.

The content (copolymerization amount) of these monomers is not particularly limited, but is preferably 0.1 to 50 mol% from the viewpoint of securing the amount of unsaturated double bonds in the molecule, and preferably 0.1 to 10%. Mole% is more preferable.

The monomer having a vinyl ester unit is not particularly limited, but vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate In addition, vinyl acetate is preferable from the viewpoint of stable polymerization.

Moreover, you may copolymerize the monomer which can be copolymerized with these monomers as needed. The copolymerizable monomer is not particularly limited, but examples thereof include olefins such as ethylene, propylene, 1-butene and isobutene, acrylic acid, methacrylic acid, crotonic acid, phthalic acid, maleic acid, itaconic acid and the like. Unsaturated acids, or salts thereof, monoalkyl esters or dialkyl esters having 1 to 18 carbon atoms, acrylamide, N-alkyl acrylamides having 1 to 18 carbon atoms, N, N-dialkyl acrylamides, diacetone acrylamides, 2 Acrylamides such as acrylamidopropanesulfonic acid and its salts, acrylamidopropyldimethylamine and its salts or quaternary salts thereof, methacrylamide, N-alkylmethacrylamide having 1 to 18 carbon atoms, N, N-dialkylmethacrylamide, di Methacrylamides such as seton methacrylamide, 2-methacrylamide propanesulfonic acid and salts thereof, methacrylamide propyldimethylamine and salts thereof or quaternary salts thereof, alkyl vinyl ethers having an alkyl chain length of 1 to 18 carbon atoms, hydroxyalkyl Vinyl ethers such as vinyl ether and alkoxyalkyl vinyl ether, N-vinyl amides such as N-vinyl pyrrolidone, N-vinyl formamide and N-vinyl acetamide, vinyl cyanides such as acrylonitrile and methacrylonitrile, vinyl chloride, vinylidene chloride, fluorine Vinyl halides such as vinyl chloride, vinylidene fluoride, vinyl bromide, vinylidene bromide, vinyl silanes such as trimethoxyvinyl silane, allyl acetate, allyl chloride, allyl alcohol Allyl compounds such as dimethyl allyl alcohol, vinyl silyl compounds such as vinyltrimethoxysilane, there is isopropenyl acetate and the like. Although the usage-amount of these copolymerizable monomers is not specifically limited, 0.001-20 mol% is preferable with respect to all the monomers to be used.

The weight average molecular weight (Mw) of the modified polyvinyl alcohol is not particularly limited, but is generally in the range of 1900 to 66500 which is generally used, and from 3800 to 28500 from the viewpoint of improving the balance between water solubility and protective colloid properties. A range is more preferred.

The method for polymerizing the monomer is not particularly limited, and a known polymerization method is used. Usually, solution polymerization using an alcohol such as methanol, ethanol or isopropyl alcohol as a solvent is performed. Bulk polymerization, emulsion polymerization, and suspension polymerization can also be performed. The solution polymerization may be continuous polymerization or batch polymerization, and the monomer may be charged all at once or dividedly, or any means such as continuous or intermittent addition may be used.

The polymerization initiator used in the solution polymerization is not particularly limited, but azobisisobutyronitrile, azobis-2,4-dimethylpareronitrile, azobis (4-methoxy-2,4-dimethylpareronitrile). ) And other azo compounds, acetyl peroxide, benzoyl peroxide, lauroyl peroxide, acetylcyclohexylsulfonyl peroxide, peroxides such as 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate, and diisopropylpropyl Percarbonate compounds such as dicarbonate, di-2-ethylhexyl peroxydicarbonate, diethoxyethyl peroxydicarbonate, t-butylperoxyneodecanate, α-cumylperoxyneodecane, t-butylperoxyneo Decanate The perester compound, azobisdimethylvaleronitrile can be used a known radical polymerization initiator such as azo-bis-methoxy valeronitrile. The polymerization reaction temperature is usually selected from the range of about 30 ° C to 90 ° C.

In saponification, a copolymer obtained by copolymerizing monomers is dissolved in alcohol, and an ester in the molecule is hydrolyzed in the presence of an alkali catalyst or an acid catalyst. Examples of the alcohol include methanol, ethanol, butanol and the like. The concentration of the copolymer in the alcohol is not particularly limited, but is selected from a range of 10 to 80% by weight. As the alkali catalyst, for example, an alkali catalyst such as an alkali metal hydroxide or alcoholate such as sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate, potassium methylate, etc. can be used. For example, an inorganic acid aqueous solution such as hydrochloric acid or sulfuric acid, or an organic acid such as p-toluenesulfonic acid can be used. These catalysts are preferably used in an amount of 1 to 100 mmol equivalents relative to the copolymer. The saponification temperature is not particularly limited, but is in the range of 10 to 70 ° C, preferably 30 to 40 ° C. Although reaction time is not specifically limited, It is performed over 30 minutes-3 hours.

The absorbance of the modified polyvinyl alcohol is not particularly limited, but it is preferable that the absorbance at 270 nm by an ultraviolet absorption spectrum of 0.2% by mass of an aqueous solution, a methanol solution, or a water-methanol mixed solution is 0.05 or more. This absorbance can be adjusted to any value by changing the amount of catalyst used in the saponification step, the saponification time, and the saponification temperature.

Here, regarding the attribution of the ultraviolet absorption spectrum, in JP-A-2004-250695, etc., the absorption at 215 nm is attributed to the structure of —CO—CH═CH— in the polyvinyl alcohol-based resin, and the absorption at 280 nm is polyvinyl alcohol-based. There is a description that it is attributed to the structure of —CO— (CH═CH) ₂ — in the resin, and the absorption at 320 nm relates to the structure of —CO— (CH═CH) ₃ — in the polyvinyl alcohol resin.

The value (Y) of Mw ′ / Mw is a value representing the dispersion state of the unsaturated double bond as described above, and is based on the ultraviolet absorption spectrum of 0.2% by mass of an aqueous solution, a methanol solution, or an aqueous methanol mixed solution. The total value (X) of the absorbance value at 280 nm and the absorbance value at 320 nm is a value representing the amount of unsaturated double bonds in the molecule. Therefore, the general formula (Equation 3) specifies the structure of the modified polyvinyl alcohol.
(Equation 3) Y = aX + b
(In the formula, a represents −0.50 or less, and b represents a value of 0.7 to 1.0.)
Here, the value of a is a value representing the dispersion state of unsaturated double bonds, and the smaller this value, the more the unsaturated double bonds are dispersed on the main chain in the molecule. The value of b is a constant and represents Mw ′ / Mw of a modified polyvinyl alcohol that does not contain an unsaturated double bond in the main chain in the molecule.
Although the value of a is not particularly limited, for example, when the obtained modified polyvinyl alcohol is used as a dispersant during suspension polymerization or a protective colloid agent during emulsion polymerization, from the viewpoint of improving its activity. It may be set in the range of −0.50 to −0.70.

In order to adjust the value of Mw ′ / Mw or the value of a, it can be adjusted by the charging method when the monomer is polymerized. For example, in order to reduce these values, the monomer may be charged continuously or divided into a polymerization can when producing modified polyvinyl alcohol.

The UV absorption spectrum derived from the double-chain structure (—CO— (CH═CH) ₂ —) of an unsaturated double bond of polyvinyl alcohol using a general aldehyde as a chain transfer agent has a peak top near 280 nm. Is derived from the structure of the general formula (Chemical Formula 13) in the modified polyvinyl alcohol of the present invention and has a peak included in the range of 265 to 275 nm at the center of 270 nm. A comparison chart is shown in FIG.

The degree of saponification of the modified polyvinyl alcohol is not particularly limited, but may generally be selected from the range of 30 mol% to 99.9 mol%.

Hereinafter, the present invention will be described in more detail with reference to examples.
Unless otherwise specified, “parts” and “%” mean “parts by mass” and “mass%”.

Example 1
<Production of modified polyvinyl alcohol>
17 parts of vinyl acetate, 14 parts of methanol, 0.023 part of dimethyl maleate and 0.10% azobisisobutyronitrile with respect to vinyl acetate are charged into the polymerization vessel, heated after nitrogen substitution and heated to the boiling point. Furthermore, a mixed solution of 6 parts of vinyl acetate, 5 parts of methanol and 0.207 parts of dimethyl maleate was continuously added until a polymerization rate of 75% was reached, and the polymerization was carried out when the polymerization rate reached 90%. Stopped. Subsequently, unpolymerized vinyl acetate was removed by a conventional method, and the resulting polymer was saponified by a conventional method with sodium hydroxide. Thereafter, it was dried with hot air at 90 ° C. for 90 minutes to obtain modified polyvinyl alcohol.

<Ozone decomposition treatment>
0.15 g of denatured polyvinyl alcohol was dissolved in 40 ml of dichloromethane, cooled to −25 ° C. to −30 ° C., and ozone was introduced at a rate of 0.041 mmol / min with respect to an oxygen flow rate of 100 ml / min while stirring. To this solution, 0.2 ml of 30% hydrogen peroxide was added and refluxed at 80 ° C. for 60 minutes and cooled to room temperature. Further, 2 g of anhydrous magnesium sulfate was added to remove water generated during the decomposition treatment, followed by suction filtration, evaporation, and vacuum drying.

<Analysis method>
The degree of saponification of the modified polyvinyl alcohol was measured according to JIS K 6276 “3.5 degree of saponification”, and the content of the unmodified polyvinyl alcohol was completely determined with an alkaline catalyst in methanol in the modified polyvinyl alcohol. The saponified and Soxhlet-extracted sample was adjusted to a concentration of 0.01 w / v% aqueous solution, and was calculated by the area ratio of the IR detector using ion exclusion HPLC. The absorbance is obtained by adjusting the absorbance of ultraviolet rays at 270 nm, 280 nm, and 320 nm after adjusting the modified polyvinyl alcohol to a 0.2 mass% aqueous solution.

<Measurement of weight average molecular weight before and after ozonolysis treatment>
This was performed under the following conditions by size exclusion chromatography (SEC).
Apparatus Pump; JASCO PU-980, thermostat; Hitachi L-5030, data processing; System Instruments SIC480II, column; Tosoh TSK-GEL MultiporeHXL-M Φ7.8 × 300 mm, 40 ° C., mobile phase: THF 1 ml / min, detector: Hitachi L-3350, sample injection amount: 0.1% 100 μL, calibration curve data: polystyrene

<Photocurability>
Dissolve 5 parts of modified polyvinyl alcohol in 45 parts of water to make an approximately 10% aqueous solution. Add 0.005 part of a photopolymerization initiator (Irgacure 2959; manufactured by Nagase Sangyo Co., Ltd.) to this aqueous solution and irradiate with UV. went.

<Emulsion polymerization of acrylic monomer>
500 parts of ion-exchanged water was added to a glass polymerization vessel equipped with a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet, 40 parts of denatured polyvinyl alcohol was added, and the mixture was heated and stirred to dissolve. Thereafter, the temperature in the polymerization vessel was set to 70 ° C., and 2 parts by weight of ammonium persulfate, 23 parts of methyl methacrylate, and 23 parts of 2-ethylhexyl acrylate were added as polymerization initiators and polymerized for 30 minutes. Next, the temperature in the polymerization vessel was raised to 80 ° C., and 207 parts of methyl methacrylate and 207 parts of 2-ethylhexyl acrylate were continuously added over 3 hours. After completion of the continuous addition, 0.05 g of ammonium persulfate was added and a ripening reaction was performed for 1 hour to complete the polymerization. The physical properties of the obtained acrylic resin emulsion were measured according to the following methods.

<Emulsion average particle size>
A laser diffraction particle size distribution analyzer “SALD 3000” (manufactured by Shimadzu Corporation) was used, and measurement was performed after ultrasonic irradiation for 5 minutes.
<Emulsion viscosity>
After the temperature of the emulsion was adjusted to 30 ° C., the viscosity was measured at 4 rpm using a BH viscometer (rotor No. 6 or No. 7).

Examples 2-6, Comparative Examples 1-3
Table 1 shows the degree of saponification, the weight average molecular weight (Mw), the type of monomer having an unsaturated double bond, the content of unmodified polyvinyl alcohol, and the amount of modified polyvinyl alcohol added during emulsion polymerization of the acrylic monomer. A sample was prepared and evaluated in the same manner as in Example 1 except for changing to.

Modified polyvinyl alcohol can be easily cured with energy rays such as ultraviolet rays and electron beams by combining with a photoinitiator, a polymerizable monomer, etc., if necessary. Effectively used for plates, etching resists, solder resists, dispersants during suspension polymerization, protective colloids during vinyl acetate emulsion polymerization, protective colloids during acrylic emulsion polymerization, protective colloids during styrene emulsion polymerization, etc. it can.

The figure which compared the ultraviolet absorption spectrum of Example 2 and Example 4, and the ultraviolet absorption spectrum of the conventional aldehyde modified polyvinyl alcohol.

Explanation of symbols

1 UV absorption spectrum 2 of Example 2 UV absorption spectrum 3 of Example 4 UV absorption spectrum 4 of conventional aldehyde-modified polyvinyl alcohol (Kuraray Co., Ltd. L-8) 72.5) UV absorption spectrum

Claims (8)

A modified polyvinyl alcohol having a bond unit represented by the general formula (Chemical Formula 1) in the molecular main chain, the weight average molecular weight (Mw) and the weight average of the polymer component obtained by ozonolysis treatment A modified polyvinyl alcohol having a relationship Mw ′ / Mw of 0.001 to 0.70 with the molecular weight (Mw ′).

(In formula, X1 and X2 represent a C1-C12 lower alkyl group, a hydrogen atom, or a metal salt. G represents the integer of 0-3. H represents the integer of 0-12. Y1. Represents a carboxylic acid, a carboxylic acid ester, a carboxylic acid metal salt or a hydrogen atom.) The relationship between the value (Y) of Mw ′ / Mw and the total value (X) of the absorbance value at 280 nm and the absorbance value at 320 nm according to the ultraviolet absorption spectrum of 0.2% by mass of an aqueous solution, methanol solution or aqueous methanol mixed solution is The modified polyvinyl alcohol according to claim 1, which satisfies the general formula (Equation 1).
(Equation 1) Y = aX + b
(In the formula, a represents −0.50 or less, and b represents a value of 0.7 to 1.0.) 2. The weight average molecular weight (Mw ′) of a polymer component obtained by ozonolysis is a weight average molecular weight of a polymer component that showed a maximum peak when the molecular weight distribution was measured. Or the modified polyvinyl alcohol of Claim 2. The absorbance at 270 nm according to the ultraviolet absorption spectrum of 0.2% by mass of an aqueous solution, a methanol solution or a water-methanol mixed solution is 0.05 or more, as described in any one of claims 1 to 3 Modified polyvinyl alcohol. The peak top of the ultraviolet absorption spectrum derived from the unsaturated double bond represented by the general formula (Chemical Formula 2) is between 265 and 275 nm, and is described in any one of claims 1 to 4 Modified polyvinyl alcohol.

The modified polyvinyl alcohol according to any one of claims 1 to 5, wherein the content of unmodified polyvinyl alcohol is 25% by mass or less. The copolymer obtained by copolymerizing at least one monomer represented by the general formula (Chemical Formula 3) to the general formula (Chemical Formula 5) and a monomer having a vinyl ester unit is saponified. The manufacturing method of modified polyvinyl alcohol as described in any one of Claims 1-6.

(In the formula, X3 and X4 represent a lower alkyl group having 1 to 12 carbon atoms, a hydrogen atom or a metal salt. I represents an integer of 0 to 12. Y2 represents a carboxylic acid, a carboxylic acid ester or a carboxylic acid. Represents a metal salt or a hydrogen atom.)

(In the formula, X5 and X6 represent a lower alkyl group having 1 to 12 carbon atoms, a hydrogen atom or a metal salt. J represents an integer of 0 to 12. Y3 represents a carboxylic acid, a carboxylic acid ester or a carboxylic acid. Represents a metal salt or a hydrogen atom.)

(In the formula, k represents an integer of 0 to 12. Y4 represents a carboxylic acid, a carboxylic acid ester, a carboxylic acid metal salt, or a hydrogen atom.) It was obtained after copolymerizing at least one of the monomers represented by the general formula (Chemical Formula 6) to the general formula (Chemical Formula 8), a monomer having a vinyl ester unit, and a monomer copolymerizable with these monomers. The method for producing a modified polyvinyl alcohol according to any one of claims 1 to 6, wherein the copolymer is saponified.

(In the formula, X3 and X4 represent a lower alkyl group having 1 to 12 carbon atoms, a hydrogen atom or a metal salt. I represents an integer of 0 to 12. Y2 represents a carboxylic acid, a carboxylic acid ester or a carboxylic acid. Represents a metal salt or a hydrogen atom.)

(In the formula, X5 and X6 represent a lower alkyl group having 1 to 12 carbon atoms, a hydrogen atom or a metal salt. J represents an integer of 0 to 12. Y3 represents a carboxylic acid, a carboxylic acid ester or a carboxylic acid. Represents a metal salt or a hydrogen atom.)

(In the formula, k represents an integer of 0 to 12. Y4 represents a carboxylic acid, a carboxylic acid ester, a carboxylic acid metal salt, or a hydrogen atom.)

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