JP5160150B2 - Method for producing esterified product and cement dispersant - Google Patents

Description

The present invention relates to a method for producing an esterified product of an alkylene oxide adduct and (meth) acrylic acid, and a cement dispersant.

Alkylene oxide adduct (meth) acrylate used as a raw material for dispersants such as cement and pigment, antistatic agent, reactive emulsifier, etc. is transesterified with alkylene oxide adduct and methyl (meth) acrylate. It has been conventionally synthesized by a method or an esterification method of an alkylene oxide adduct and (meth) acrylic acid. Of these, the latter esterification method is generally a synthesis method in which the reaction product water is removed from the alkylene oxide adduct and excess (meth) acrylic acid in the presence of a strongly acidic catalyst such as sulfuric acid or paratoluenesulfonic acid. It is.
There are two methods for removing the reaction product water: a method using a dehydrated solvent and a method using no dehydrated solvent. Among these methods, a method using a dehydrated solvent has the advantage of correspondingly high quality, but it was used. It is necessary to recover the dehydrated solvent. The recovery of the dehydrated solvent used increases the production cost of the esterified product including the installation of the recovery equipment, and there is a problem in that the operator is forced to perform the recovery operation in an unfavorable environment due to its property. For this reason, the method of manufacturing an alkylene oxide adduct (meth) acrylic acid ester is proposed, without using a dehydration solvent (patent document 1). However, when no dehydrating solvent is used, a side reaction is likely to occur during the esterification reaction of the alkylene oxide adduct and (meth) acrylic acid, and the method of Patent Document 1 also generates a by-product during the esterification reaction. It is difficult to suppress, and because of the presence of by-products such as a polymer, the copolymer having the esterified product as a monomer has insufficient dispersion effect as a cement dispersant. Further, when no dehydrating solvent is used, there is a problem that the esterified product is easily colored, so that it is difficult to use it as it is as an antistatic agent or a reactive emulsifier.

JP 2001-172383 A

An object of the present invention is to provide a method for producing an esterified product in which an alkylene oxide adduct and (meth) acrylic acid are esterified using an acid catalyst in the absence of a dehydrating solvent. The present invention is to provide a method for producing an esterified product that is greatly suppressed and the esterified product is difficult to be colored, and is excellent in dispersibility comprising a copolymer having the obtained esterified product as one kind of monomer. Is to provide a cement dispersant.

As a result of intensive studies to solve the above problems, the present inventor has reached the present invention. That is, the present invention is an esterified product in which an alkylene oxide adduct (a1) represented by the general formula (1) and (meth) acrylic acid (a2) are esterified in the absence of a solvent in the presence of an acid catalyst. In the production method, 0.01 to 0.8% by weight of hydroquinone monomethyl ether (b1) and 0.01 to 3.0% by weight based on the total amount of the alkylene oxide adduct (a1) and (meth) acrylic acid (a2). A method for producing an esterified product (A), characterized in that a weight percent hypophosphorous acid (salt) (b2) is used in an esterification reaction; obtained by the production method and 5.5 on the H ¹ -NMR chart Esterified product in which the ratio (α) of the peak area of 1.0 to 1.5 ppm to the area of the peak of ˜6.5 ppm is 0.5 or less; the esterified product and unsaturated carboxylic acid (salt) ( ) Required configuration composed of a copolymer comprising as monomers a cement dispersing agent; a.
RO (AO) n-H (1)
In the formula, R represents a residue of a monohydric alcohol having 1 to 12 carbon atoms, A represents an alkylene group having 2 to 4 carbon atoms, and n represents a number of 1 to 200.

In the esterified product obtained by the production method of the present invention, the formation of by-products during the esterification reaction is greatly suppressed and the coloring is small. Further, a cement dispersant made of a copolymer comprising the esterified product and an unsaturated carboxylic acid (salt) as constituent monomers is superior in dispersibility compared to the conventional one.

In the general formula (1) in the present invention, R is a residue of a monohydric alcohol having 1 to 12 carbon atoms. Examples of the monohydric alcohol include aliphatic monohydric alcohol, aromatic monohydric alcohol, and araliphatic 1 And monohydric alcohols.

Examples of the aliphatic monohydric alcohol include methyl alcohol, ethyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, n-pentyl alcohol, n-hexyl alcohol, n-octyl alcohol, 2-ethylhexyl alcohol, n-decyl. And linear or branched saturated aliphatic alcohols such as alcohol and lauryl alcohol, and cyclic aliphatic alcohols such as cyclohexyl alcohol and ethylcyclohexyl alcohol. Examples of the aromatic monohydric alcohol include phenol and ethylphenol. Examples of the araliphatic monohydric alcohol include benzyl alcohol. The monohydric alcohol may be a natural alcohol or a synthetic alcohol (Ziegler alcohol, oxo alcohol, etc.). Of the alcohols, aliphatic monohydric alcohols are preferred.

Examples of the alkylene group having 2 to 4 carbon atoms represented by A in the general formula (1) include an ethylene group, a 1,2-propylene group, a 1,3-propylene group, a 1,2-butylene group, and a 1,4-butylene group. And a butylene group.

n is a number from 1 to 200, preferably a number from 6 to 100. Since (a1) is an alkylene oxide adduct, there is usually a distribution in the number of moles of alkylene oxide added. Accordingly, the alkylene oxide adduct (a1) is composed of a mixture of compounds having different addition mole numbers, and n is an average value of the addition mole numbers and is not necessarily an integer.

The alkylene oxide adduct (a1) is produced by an ordinary production method, that is, by adding 1 to 200 mol of an alkylene oxide having 2 to 4 carbon atoms on average to a monohydric alcohol having 1 to 12 carbon atoms. As the catalyst in the addition reaction, known catalysts such as alkali metal hydroxides and acidic compounds can be used. The temperature of the addition reaction is usually 50 to 180 ° C.

Examples of the alkylene oxide having 2 to 4 carbon atoms include ethylene oxide (hereinafter abbreviated as EO) alone; EO and other alkylene oxides [1,2-propylene oxide (hereinafter abbreviated as PO), 1,2-butylene oxide. Side, tetrahydrofuran, alkylene oxide substituted products (epichlorohydrin) and the like], and a mixture of two or more of these.

(Meth) acrylic acid (a2) in the present invention represents acrylic acid, methacrylic acid, and a combination of acrylic acid and methacrylic acid. Of these, methacrylic acid is preferred.

Examples of the acid catalyst used in the esterification reaction include inorganic acids such as sulfuric acid and hydrochloric acid, and organic acids such as methanesulfonic acid, paratoluenesulfonic acid, xylenesulfonic acid, and naphthalenesulfonic acid. In this case, the acid catalyst may be used alone or in the form of a mixture of two or more. The addition amount of the acid catalyst is 0.01 to 10.0% by weight, more preferably 0.1 to 1% by weight, based on the total amount of the alkylene oxide adduct (a1) and (meth) acrylic acid (a2). It is.

The amount of hydroquinone monomethyl ether (b1) used in the esterification reaction is usually 0.01 to 0.8% by weight, preferably 0.08 to 0%, based on the total amount of (a1) and (a2). .5% by weight. If it is less than 0.01% by weight, the polymerization reaction tends to occur, and the reaction system may gel. Even if an amount exceeding 0.8% by weight is added, the polymerization inhibiting effect reaches an equilibrium.

In the present invention, hypophosphorous acid (salt) (b2) represents hypophosphorous acid, hypophosphite, and a combination of hypophosphorous acid and hypophosphite.

Hypophosphites include alkali metal salts of hypophosphorous acid such as sodium, potassium and lithium; amine salts and ammonium salts such as monomethylamine, dimethylamine, trimethylamine, diethylamine, monoethanolamine, diethanolamine and triethanolamine And so on. Of the hypophosphorous acid (salt) (b2), sodium hypophosphite and hypophosphorous acid are preferred, and hypophosphorous acid is particularly preferred. The amount of hypophosphorous acid (salt) (b2) added is usually 0.01 to 3.0% by weight, preferably 0.05 to 0.5% by weight, based on the total amount of (a1) and (a2). %. If it is less than 0.01% by weight, the esterified product tends to be colored. Further, even when an amount exceeding 3.0% by weight is added, the coloring suppression effect reaches an equilibrium, and the generation of by-products in the esterified product tends to increase.

The production method of the esterified product of the present invention is such that hydroquinone monomethyl ether (b1) and hypophosphorous acid (salt) (b2) are added in the above amounts, respectively, thereby coloring the esterified product, polymer during reaction, etc. The amount of by-products produced is suppressed. When either (b1) or (b2) is less than 0.01% by weight, both by-products and coloring during the reaction are not suppressed. In particular, when hypophosphorous acid (salt) (b2) is less than 0.01% by weight, a polymerization reaction is likely to occur, and the reaction system may be gelled. In order to obtain an esterified product with low coloration and less by-products with higher purity, the weight ratio (b1) / (b2) between (b1) and (b2) is preferably 0.1-2. More preferably, it is 0.15-1, Most preferably, it is 0.2-0.9.

As means for removing reaction product water out of the system during the esterification reaction, a carrier gas is blown into the reaction system and the product water is taken out of the system together with the carrier gas. Examples thereof include a method of distilling out of the system and a method combining these.

Among these methods, a method of reducing the pressure in the reaction system while preferably blowing a carrier gas can be mentioned. Examples of the carrier gas include air, nitrogen gas, oxygen gas, helium gas, argon gas, and carbon dioxide gas. Among these gases, air or oxygen gas having an effect of blocking radicals generated in the reaction system is preferable, and air or oxygen gas may be used alone or mixed with other gases. May be used. When the inside of the reaction system is reduced in pressure, the reaction raw material components (a1) and (a2) remain in the system, and preferably only the produced water is distilled out of the system. Generally, the conditions are 2 kPa to 70 kPa. Is preferred. The reaction temperature in the esterification reaction is preferably 105 to 135 ° C.

The equivalence ratio of (a1) and (a2) in the esterification reaction is not particularly limited, but usually a ratio in which one is excessive is preferable. Specifically, with respect to 1 mol of (a1), (A2) is 1.0 to 30 mol, preferably 1.2 to 15 mol. The end point of the esterification reaction is when the hydroxyl value of the esterified product is analyzed and the reaction rate becomes 95% or more.

In the H ¹ -NMR chart, the esterified product obtained by the production method of the present invention has an area ratio (α) of a peak of 1.0 to 1.5 ppm to an area of a peak of 5.5 to 6.5 ppm of 0. 5 or less, preferably 0.2 or less.

The peak area of 1.0 to 1.5 ppm is considered to correlate with the amount of methylene group and methyl group of the by-product, and the peak area of 5.5 to 6.5 ppm is the same as that of the (meth) acryloyl group. It is thought to correlate with the amount of heavy bonds. Therefore, the area ratio (α) is considered to be an indicator of the content of by-products. If the esterified product having α exceeding 0.5 is used as a monomer as it is, the quality of the resulting polymer is insufficient, and in particular, dispersibility as a cement dispersant cannot be exhibited.

The esterified product obtained by the production method of the present invention has a hue by the Hazen colorimetric method of 50 or less, preferably 40 or less. The esterified product having a hue of more than 50 according to the Hazen colorimetric method causes coloring of the resulting resin or fiber when used as an antistatic agent, and coloring of the resulting resin emulsion when used as a reactive emulsifier. Cause.

The cement dispersant of the present invention comprises a copolymer comprising the esterified product (A) and the unsaturated carboxylic acid (salt) (B) as essential constituent monomers. Examples of the unsaturated carboxylic acid (salt) (B) include acrylic acid, methacrylic acid, maleic acid, and salts thereof. Examples of the salt include alkali metal (potassium, sodium, etc.) salt, ammonium salt, amine (alkylamine having an alkyl group having 1 to 4 carbon atoms, such as trimethylamine, triethanolamine, monobutylamine) salt, quaternary ammonium. Salts (tetraalkylammonium salts having 1 to 4 carbon atoms in the alkyl group: for example, tetramethylammonium salt, trimethylethylammonium salt) and the like are included.

The molar ratio of the esterified product / unsaturated carboxylic acid (salt) in the copolymer is preferably 10 to 95/90 to 5, more preferably 20 to 85/80 to 15, and most preferably 30 to 65/70 to. 35.

In addition to the esterified product (A) and the unsaturated carboxylic acid (salt) (B), the copolymer further comprises (meth) acrylamide, (meth) acrylonitrile, allyl alcohol and an alkylene oxide adduct of allyl alcohol, allyl A sulfonic acid (salt) and a hydrophilic vinyl monomer described in JP-A-2006-124210 and JP-A-2006-206367 may be used. The total of the esterified product (A) and the unsaturated carboxylic acid (salt) (B) in the copolymer is preferably 80 mol% or more, more preferably 70 mol% or more of all monomers.

As the method for producing the copolymer, a known polymerization method can be applied, and examples thereof include solution polymerization, suspension polymerization, bulk polymerization, reverse phase suspension polymerization, and emulsion polymerization. Among these polymerization methods, solution polymerization, suspension polymerization, reverse phase suspension polymerization or emulsion polymerization is preferable, more preferably solution polymerization, reverse phase suspension polymerization or emulsion polymerization, particularly preferably solution polymerization or emulsion polymerization, Solution polymerization is preferred. For this polymerization, known polymerization initiators, chain transfer agents and / or solvents can be used.
The weight average molecular weight (Mw) of the copolymer is preferably from 1,000 to 1,000,000, more preferably from 3,000 to 500,000, particularly preferably from 5,000 to 100,000, from the viewpoint of dispersibility and the like. Further, the molecular weight distribution {ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn)} is preferably 1 to 4, more preferably 1.5 to 3, particularly preferably 2 to 2. .5. The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC) method (standard substance: polyethylene glycol).

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. In the following, parts and% indicate parts by weight and% by weight, respectively.

In addition, the weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the copolymer were obtained by GPC measurement under the following conditions.
Apparatus: Waters GPC system [pump; Model 510]
Column: TSKgel G3000PWXL and TSKgel G50000PWXL 7.8 ml I.D. Column temperature coupled in series with D 30cm: 40 ° C
Developing solvent: water / methanol (volume ratio = 70: 30) + sodium acetate (0.5%)
Flow rate: 1.0 (ml / min)
Detector: waters410
Reference material: Polyethylene glycol

<Example 1>
A SUS autoclave equipped with a thermometer, a stirrer, and a SUS dropping funnel was charged with 32 parts of methanol and 0.4 part of sodium hydroxide, and after the inside of the container was sufficiently purged with nitrogen, the container was sealed and heated to 100 ° C. . After 132 parts of ethylene oxide was dropped from the dropping funnel over 1 hour and reacted at 150 ° C. or lower, the temperature was raised to 180 ° C., and 880 parts of ethylene oxide was dropped from the dropping funnel over 3 hours to react. Further, after aging at 180 ° C. for 1 hour, the mixture was cooled to 25 ° C. Transfer the contents to a glass reactor equipped with a thermometer, stirrer, product water separator, reflux condenser, 8 parts hydroquinone monomethyl ether, 19 parts hypophosphorous acid, 6 parts sulfuric acid, and 860 parts methacrylic acid. Esterification at 120 ° C while charging, gradually increasing the temperature while supplying a small amount of air and reducing the pressure while distilling water produced by the esterification reaction out of the reaction system at a reduced pressure of 40 kPa. Reaction was performed. Subsequently, the remaining excess methacrylic acid was further distilled off at a reduced pressure, so that methoxypolyethylene glycol having a hydroxyl value of 0.5, a weak acid value of 7.4, and an esterification rate of 99% calculated from the hydroxyl value (addition) Mole number 23) methacrylate was obtained.

In addition, (b1) preparation amount (%) of hydroquinone monomethyl ether with respect to the total amount of alkylene oxide adduct and methacrylic acid in Example 1 and the following Examples 2-3 and Comparative Examples 1-4, (b2) hypophosphorous acid The amount of acid (salt) charged (%), (b1) / (b2), product hue (Hazen colorimetric test method), and α are shown in Table 1.

<Example 2>
A SUS autoclave equipped with a thermometer, a stirrer, and a SUS dropping funnel was charged with 186.3 parts of lauryl alcohol and 1.6 parts of potassium hydroxide, and after the inside of the container was sufficiently purged with nitrogen, the container was sealed and heated to 180 ° C. The temperature was raised, and 4400 parts of ethylene oxide was dropped from the dropping funnel over 5 hours to be reacted. Further, after aging at 180 ° C. for 1 hour, the mixture was cooled to 25 ° C. Transfer the contents to a glass reactor equipped with a thermometer, stirrer, product water separator, reflux condenser, 26 parts hydroquinone monomethyl ether, 29 parts sodium hypophosphite, 54 parts sulfuric acid, and 1290 parts methacrylic acid While stirring, the temperature was gradually raised while supplying a small amount of air and the pressure was reduced, and the water produced by the esterification reaction was distilled out of the reaction system at a reduced pressure of 40 kPa, and the ester was added at 120 ° C. The reaction was carried out. Subsequently, the excess methacrylic acid remaining was distilled off at a further reduced pressure, whereby a polyethylene glycol lauryl ether having a hydroxyl value of 0.7, a weak acid value of 5.6, and an esterification rate of 99% calculated from the hydroxyl value ( An addition mole number of 100 moles of methacrylate was obtained.

<Example 3>
A SUS autoclave equipped with a thermometer, a stirrer and a SUS dropping funnel was charged with 32 parts of methanol and 0.1 part of sodium hydroxide, and the container was sufficiently purged with nitrogen, then sealed and heated to 100 ° C. . After 132 parts of ethylene oxide were dropped from the dropping funnel over 1 hour and reacted, the temperature was raised to 180 ° C., and 132 parts of ethylene oxide was dropped from the dropping funnel over 0.5 hour to react. Further, after aging at 180 ° C. for 1 hour, the mixture was cooled to 25 ° C. Transfer the contents to a glass reactor equipped with a thermometer, stirrer, product water separator, reflux condenser, 1 part hydroquinone monomethyl ether, 4.4 parts hypophosphorous acid, 1.0 part sulfuric acid, and acrylic While adding 144 parts of acid and gradually stirring while supplying a slight amount of air, the pressure was reduced and the water produced by the esterification reaction was distilled out of the reaction system at a reduced pressure of 70 kPa. The esterification reaction was performed at 0 ° C. Next, the remaining excess acrylic acid was further distilled off at a reduced pressure, so that methoxypolyethylene glycol having a hydroxyl value of 0.3, a weak acid value of 3.4, and an esterification rate of 99% calculated from the hydroxyl value (addition) Mole number 6 mol) acrylate was obtained.

<Comparative Example 1>
The same procedure as in Production Example 1 was carried out except that hypophosphorous acid was not added and the hydroquinone monomethyl ether was changed to p-benzoquinone, and the esterification reaction was carried out.

<Comparative example 2>
The same procedure as in Example 1 was carried out except that 19 parts of hypophosphorous acid was changed to 95 parts, and a methoxypolyethylene glycol (addition) having a hydroxyl value of 0.5, a weak acid value of 5.8, and an esterification rate of 99% calculated from the hydroxyl value. Mole number 23) methacrylate was obtained.

<Comparative Example 3>
A polyethylene glycol having a hydroxyl value of 1.2, a weak acid value of 5.2, and an esterification rate of 99% calculated from the hydroxyl value, except that 29 parts of sodium hypophosphite was changed to 0.29 part. Methacrylate of lauryl ether (added mole number 100 mol) was obtained.

<Comparative example 4>
Methoxypolyethylene glycol having the esterification rate of 99% calculated from the hydroxyl value of 0.5, the weak acid value of 4.4, and the hydroxyl value by performing the same operation as in Example 3 except that 4.4 parts of hypophosphorous acid was changed to 22 parts. (Addition mole number 6 mol) An acrylate was obtained.

<Example 4>
In a polymerization reaction vessel, 600 parts of water was charged, while stirring, the inside of the reaction vessel was replaced with nitrogen gas, and the temperature of water was heated to 80 ° C. in a nitrogen atmosphere. Next, a monomer solution consisting of 556 parts (0.5 mole part) of the monomer obtained in Example 1, 43 parts (0.5 mole part) of methacrylic acid, 60 parts of water and 0.3 part of mercaptoethanol was prepared. The solution was dropped into the polymerization reaction vessel over 2 hours. Simultaneously with the start of the dropping, an aqueous catalyst solution comprising 13 parts of ammonium persulfate and 180 parts of water was added dropwise over 2.5 hours. After completion of the dropwise addition of the catalyst aqueous solution, the mixture was further reacted at 80 ° C. for 1 hour to obtain a polymerization solution. Next, a 50% aqueous sodium hydroxide solution was added to the polymerization solution cooled to 25 ° C. so as to have a pH of 7, thereby obtaining a cement dispersant (1) comprising an aqueous solution of the copolymer (P1). The weight average molecular weight (Mw) of (P1) was 30000, and the molecular weight distribution (Mw / Mn) was 1.8.

<Example 5>
The same procedure as in Example 4 was conducted except that 556 parts (0.50 mole part) of the monomer obtained in Example 1 was changed to 175 parts (0.50 mole part) of the monomer obtained in Example 3. A cement dispersant (2) comprising an aqueous solution of the copolymer (P2) was obtained. The weight average molecular weight (Mw) of the copolymer (P2) was 35000, and the molecular weight distribution (Mw / Mn) was 1.8.

<Comparative Example 5>
Except that 556 parts (0.50 mole part) of the monomer obtained in Example 1 was changed to 556 parts (0.50 mole part) of the monomer obtained in Comparative Example 2, the same procedure as in Example 4 was performed. A cement dispersant (3) comprising an aqueous solution of the copolymer (P3) was obtained. The weight average molecular weight (Mw) of the copolymer (P3) was 30000, and the molecular weight distribution (Mw / Mn) was 1.8.

<Comparative Example 6>
The same procedure as in Example 5 was conducted except that 556 parts (0.50 mole part) of the monomer obtained in Example 3 was changed to 175 parts (0.50 mole part) of the monomer obtained in Comparative Example 4. A cement dispersant (4) comprising an aqueous solution of the copolymer (P4) was obtained. The weight average molecular weight (Mw) of the copolymer (P4) was 35000, and the molecular weight distribution (Mw / Mn) was 1.8.

(1) Preparation of evaluation mortar An evaluation mortar was prepared with the formulation shown in Table 2 in accordance with 10.4.3 mixing method of JIS R5201-1997.

(2) Flow test Based on JIS R5201-1997 "11. Flow test", the flow value (mm) was obtained by the flow test. The results are shown in Table 3. In addition, it means that fluidity | liquidity is so favorable that a numerical value is large.

Since the esterified product obtained by the production method of the present invention has few by-products, the copolymer obtained by copolymerizing it is of high quality and can be used as a cement dispersant exhibiting excellent dispersibility. . In addition, since the esterified product is less colored, it is useful as an antistatic agent or a reactive emulsifier.

Claims (3)

In the method for producing an esterified product in which an alkylene oxide adduct (a1) represented by the general formula (1) and (meth) acrylic acid (a2) are esterified in the absence of a solvent in the presence of an acid catalyst, 0.01 to 0.8% by weight of hydroquinone monomethyl ether (b1) and 0.01 to 3.0% by weight of hypochlorous acid based on the total amount of alkylene oxide adduct (a1) and (meth) acrylic acid (a2) The phosphoric acid (salt) (b2) is obtained by a method for producing an esterified product (A), characterized in that it is used in an esterification reaction, and H ¹ -In the NMR chart, the esterified product (A) in which the ratio (α) of the peak area of 1.0 to 1.5 ppm to the peak area of 5.5 to 6.5 ppm is 0.5 or less, and the unsaturated carboxylic acid A cement dispersant comprising a copolymer having acid (salt) (B) as an essential constituent monomer.
RO (AO) n-H (1)
(Wherein R is a residue of a monohydric alcohol having 1 to 12 carbon atoms, and A is an alkyle having 2 to 4 carbon atoms.
N represents a number of 1 to 200. ) Esterification reaction at a temperature of 105 to 135 ° C. and a pressure of 2 kPa to 70 kPa
The cement dispersant according to claim 1, wherein: The cement dispersant according to claim 1 or 2, wherein the hypophosphorous acid (salt) (b2) is hypophosphorous acid.
.