JP5392642B2 - Method for producing styrene-maleic anhydride copolymer - Google Patents

Description

The present invention relates to a method for producing a copolymer obtained by using styrene and maleic anhydride as starting materials, and further an esterified product, a hydrolyzate or a salt thereof.

[Prior art]
It is known that water-soluble polymers can be obtained by copolymerizing styrene and maleic anhydride by radical polymerization and then resinating, esterifying and hydrolyzing or hydrolyzing, for example, Polymer Chemistry 1963 20 646-648 , Polymer Chemistry 1963, 2049-652, and Occupational Chemistry Magazine 1974, 74, pp. 298-301. That is not touched. Generally, 2,4-diphenyl-4-methyl-1-pentene, 2,4-diphenyl-4-methyl-2-pentene, 1,1,3-trimethyl-3, such as those commercially available from Goi Kasei. -Desired viscosity can be obtained by adding a chain transfer agent such as phenylindane or α-methylstyrene. However, depending on the intended use, the chain transfer agent remains in the product and causes adverse effects, so that there are restrictions on the use. A desired viscosity can be obtained using a solvent such as benzene, dioxane or dioxolane without using a chain transfer agent, but benzene and dioxane are problematic for health effects, and whether dioxolane is safe for health effects. There is not enough data.

Problems to be solved by the invention

The object of the present invention is to produce a copolymer having styrene and maleic anhydride as starting materials, and its esterified product, hydrolyzate or salt thereof, a molecular weight regulator, a solvent having high health effects on humans such as benzene and dioxane. It is providing the manufacturing method which controls molecular weight, without using.

Means for solving the problem

As a result of intensive studies on a method for producing a styrene-maleic anhydride copolymer having the above-mentioned problems, the present inventor has found that molecular weight regulators, benzene, dioxane and the like are not used as solvents having high health effects on humans. The present inventors have found that a desired viscosity can be obtained by controlling the molecular weight by radical polymerization in a system in which mixed solvents are combined.

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(ハ)In the present invention, a copolymer obtained by using styrene and maleic anhydride as starting materials, and further an esterified product, a hydrolyzate or a salt thereof are represented by the following one-step formulas (A), (B) and (C).

(I)

(B)

(C)

  In the formula, M represents hydrogen or an organic base, and an inorganic base represents an alkali metal or an alkaline earth metal. m, n, o, p, and q are values indicating the mol% of each monomer, m is 45 to 75, n is 25 to 55, and o, p, and q are each 0 to 45. 55, m + n = 100, o + p + q = n. R is —O—R1 or —N (—R1, —R2), R1 represents an alkyl group, a halogenoalkyl group, a halogenoalkyloxyalkyl group, an aralkyl group, an aryl group, and R2 represents hydrogen or a lower alkyl group. .

The average molecular weight in the present invention is 100,000 to 800,000.

The radical polymerization method in the present invention is not particularly limited, and a conventionally known method can be used as it is, but the initiator is α, α′-azobisisobutyronitrile (AIBN) depending on the polymerization conditions. ), Benzoyl peroxide (BPO), azobiscyanovaleric acid (ACVA) and the like are preferably used.

The amount of the initiator may be 0.01% to 5% with respect to styrene, and preferably 0.1% to 3% is preferable in terms of handling and economy.

The solvent may be acetone or methyl ethyl ketone as a ketone solvent, and a mixed solvent such as toluene or xylene as an aromatic hydrocarbon solvent, but a mixed solvent of acetone and toluene is particularly preferable. The mixing ratio of the ketone solvent / aromatic hydrocarbon solvent is 95/5 to 5/95 (volume ratio) depending on the desired viscosity, but is preferably 95/5 to 70/30 (volume ratio). .

The amount of the mixed solvent used may be 1 to 20 times the amount of styrene, and preferably 1 to 3 times the amount for handling and economy.

The radical polymerization temperature is 40 to 200 ° C., preferably 55 to 100 ° C., although it depends on the ratio of the mixed solvent and the initiator efficiency. If it is less than 40 ° C., the reaction does not start. Consideration is necessary for the heating method above 150 ° C., and if it exceeds 200 ° C., there is a risk of thermal decomposition of the copolymer.

The copolymer in the present invention can be removed by solvent removal under reduced pressure, or after reprecipitation in a hydrocarbon solvent, and then dried and taken out. I can do it.

When esterification is performed, there is no problem in the esterification reaction even if there is a mixed solvent used for copolymerization in addition to alcohols or amines used in the reaction. An esterification catalyst can also be used.

Moreover, although reaction temperature is based also on the ratio of a mixed solvent, it is 30-150 degreeC, Preferably it is 50-10.
0 ° C. If it is less than 50 ° C., the esterification reaction is slow, and if it exceeds 100 ° C., it is necessary to consider the heating method, and if it exceeds 150 ° C., there is a risk of thermal decomposition of the copolymer.

The esterification reaction time depends on the alcohol or amine to be used and the reaction temperature, but the reaction can be carried out effectively in 1 to 30 hours, preferably 3 to 14 hours.

The hydrolysis of the copolymer in the present invention may be carried out after reprecipitation in a hydrocarbon solvent and then dried and taken out as a powder, or may be carried out as it is without adding the solvent to an alkaline aqueous solution. I can do it. As the alkaline agent, sodium hydroxide, potassium hydroxide, aqueous ammonia and the like are economically preferable.

Moreover, although the temperature of a hydrolysis is based also on the alkali agent to be used, it is 10-100 degreeC, Preferably it is 30-80 degreeC. If it is less than 30 ° C., the hydrolysis reaction is slow. When esterification is performed, if the temperature exceeds 80 ° C., the ester may be hydrolyzed by heat.

In order to explain the present invention in more detail, the following examples are given, but the present invention is not limited to these examples.

Gel permeation chromatography (hereinafter abbreviated as GPC) was measured using a Tosoh apparatus and a solvent.

Pump: CCPM, detection unit: RI-8010, column: G6000PWxl, G3000PWxl connected, column temperature: 40 ° C., data processing device: SC-8020, solvent solution: 20 mmoll sodium carbonate + 20 mmol disodium hydrogenphosphate aqueous solution (pH 11.5) The molecular weight of the mixed solution was calculated based on a calibration curve using polystyrene of known molecular weight as standard data.

The infrared absorption spectrum was measured using a Horiba FT-200 apparatus, and when the solvent was removed from the resin, a KBr tablet was used. In the case of a solution, it was measured by the difference spectrum method by the ATR method.

The viscosity was measured at 25 ° C. with a B-type viscometer manufactured by TOKIMEC.

Example 1
A 1000 ml four-necked flask equipped with a stirrer, thermometer, and reflux condenser was charged with 45 g of styrene, 43 g of maleic anhydride, 35 ml of toluene, 315 ml of acetone and 0.2 g of benzoyl peroxide, and heated in an oil bath under reflux. , Reacted for 6 hours. Thereafter, 16 g of fluorinated alcohol (HCF2CF2OH) was added and the esterification reaction was carried out at 65 ° C. for 7 hours. Next, this esterification solution was added to an aqueous solution in which 27 g of sodium hydroxide was dissolved in 350 g of water, hydrolyzed at 60 ° C. for 5 hours, and then cooled to 15 ° C. or lower to precipitate the resin portion. After removing the separated upper organic layer and separated water, water was added to adjust to 6%.
The obtained water-soluble polymer had a weight average molecular weight of 300,000, and a 6% aqueous solution having a viscosity of 60 mPa · s and an ester bond near 1740 cm −1 attributable to the ester could be confirmed in the infrared absorption spectrum.

Example 2
A 1000 ml four-necked flask equipped with a stirrer, thermometer, and reflux condenser is charged with 45 g of styrene, 43 g of maleic anhydride, 35 ml of toluene, 315 ml of acetone, and 1 g of Nipa-BW (benzoyl peroxide paste product manufactured by NOF Corporation). The mixture was heated in an oil bath and reacted for 6 hours under reflux. This reaction solution is put into 1500 ml of hexane to precipitate a resin, which is filtered and dried. The dried styrene-maleic anhydride copolymer was dissolved in an aqueous sodium hydroxide solution and the molecular weight was measured. The obtained water-soluble polymer had a weight average molecular weight of 380,000, and a 6% aqueous solution viscosity of 80 mPa · s could be confirmed.

Example 3
A 1000 ml four-necked flask equipped with a stirrer, thermometer, and reflux condenser is charged with 45 g of styrene, 43 g of maleic anhydride, 70 ml of toluene, 280 ml of acetone and 1 g of Nipa-BW (benzoyl peroxide paste product manufactured by NOF Corporation). The mixture was heated in an oil bath and reacted for 6 hours under reflux. This reaction solution was added to an aqueous solution in which 27 g of sodium hydroxide was dissolved in 350 g of water, hydrolyzed at 60 ° C. for 5 hours, and then cooled to 15 ° C. or lower to precipitate the resin portion. After removing the separated upper organic layer and separated water, water was added to adjust to 12%.
The obtained water-soluble polymer had a weight average molecular weight of 230,000, and a 6% aqueous solution viscosity of 45 mPa · s could be confirmed.

Comparative Example 1
A 1000 ml four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser is charged with 45 g of styrene, 43 g of maleic anhydride, 350 ml of toluene, and 1 g of Nypa-BW (benzoyl peroxide paste product manufactured by NOF Corporation). And reacted for 6 hours under reflux. An aqueous solution in which 27 g of sodium hydroxide was dissolved in 350 g of water was added to this reaction liquid, and after hydrolysis at 60 ° C. for 5 hours, toluene was removed by steam distillation, and water was added to adjust to 12%.
The weight average molecular weight of the obtained water-soluble polymer was 50,000, and the viscosity of 6% aqueous solution was 12 mPa · s.

Comparative Example 2
In a 1000 ml four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, 45 g of styrene, 43 g of maleic anhydride, 350 ml of acetone and 1 g of Nypa-BW (benzoyl peroxide paste product manufactured by NOF Corporation) are placed in an oil bath. And reacted for 6 hours under reflux. This reaction solution was added to an aqueous solution in which 27 g of sodium hydroxide was dissolved in 350 g of water, hydrolyzed at 60 ° C. for 5 hours, and then cooled to 15 ° C. or lower to precipitate the resin portion. After removing the separated upper organic layer and separated water, water was added to adjust to 12%.
The weight average molecular weight of the obtained water-soluble polymer was 1,000,000 or more, and the viscosity of 6% aqueous solution was confirmed to be 400 mPa · s or more.

Comparative Example 3
In a 1000 ml four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, 45 g of styrene, 43 g of maleic anhydride, 350 ml of dioxane and 0.15 g of Nypa-BW (Nippon Fatty Fatty Benzoyl peroxide paste product) were placed. The mixture was heated in an oil bath and reacted for 6 hours under reflux. This reaction solution is put into 1500 ml of hexane to precipitate a resin, which is filtered and dried. The dried styrene-maleic anhydride copolymer was dissolved in an aqueous sodium hydroxide solution and the molecular weight was measured. The obtained water-soluble polymer had a weight average molecular weight of 280,000, and a 6% aqueous solution viscosity of 58 mPa · s could be confirmed.

Effect of the invention

According to the present invention, in the production of a copolymer using styrene and maleic anhydride as starting materials, and its esterified product, hydrolyzate or salt thereof, a molecular weight regulator or a solvent having high health effects on humans such as benzene and dioxane is added. It was possible to provide a production method for controlling the molecular weight without using it.

Claims (1)

Copolymerization ratio of styrene unit and maleic anhydride is 45 to 75 to 55 to 25 (mol%), and a ketone solvent and benzene are excluded as reaction solvents in order to obtain a weight average molecular weight of 100,000 to 800,000. A method for producing a styrene-maleic anhydride copolymer, wherein a mixed solvent of an aromatic hydrocarbon solvent is used.