JP3309401B2 - Maleic anhydride copolymer and scale inhibitor using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a maleic anhydride copolymer, a water-soluble maleic acid copolymer which is a hydrolyzate thereof,
The present invention relates to a method for producing the maleic anhydride copolymer and a scale inhibitor containing the water-soluble maleic acid copolymer.

[0002]

2. Description of the Related Art In general, natural water, tap water, industrial water and the like contain various impurities. As impurities, calcium, magnesium,
There are cations such as iron and barium and anions such as carbonate ion, hydrogen carbonate ion, sulfate ion and silicate ion. Furthermore, in some cases, zinc ions and phosphate ions may be contained as anticorrosives. These waters are used as circulating water for devices such as boilers, cooling towers, evaporators, and heat exchangers. However, in these devices, the water is heated, cooled, and sometimes the pH changes, so that the ions contained in the water become insoluble salts, deposit on the inner walls of the device, and adhere to the scale, often causing scale. Form. The formation of scale causes a decrease in heat transfer efficiency and cooling efficiency, an increase in flow path resistance, and causes corrosion of the device.

[0003] As a scale inhibitor, for example, lignin compounds, phosphorus compounds, acrylic acid polymer compounds, maleic acid polymer compounds and the like are used. Among them, maleic acid-based polymer compounds, for example, a hydrolyzate of a maleic anhydride homopolymer or a hydrolyzate of a maleic anhydride-monoolefin copolymer are known to have an excellent scale preventing effect [ Japanese Patent Publication No. 53-2047
No. 5, 54-29998, JP-A-53-70089
No. 60-71093]. However, the effect of preventing adhesion of calcium ions and the like, which are the main components of the scale, was not always satisfactory. That is, when the concentration of the maleic acid-based polymer was set to a relatively low concentration, for example, 20 ppm or less, it was not possible to effectively prevent the adhesion of scales such as calcium ions. Furthermore, precipitation of iron ions, which are scale components other than calcium, could not be sufficiently prevented.

[0004] Among the maleic acid-based polymer compounds, hydrolysates of maleic anhydride homopolymer are particularly excellent as scale inhibitors. However, at the time of production, it is necessary to use a relatively large amount of a polymerization initiator which is relatively expensive, and there is a problem that a hydrolyzate of a maleic anhydride homopolymer to be produced becomes expensive.

Accordingly, an object of the present invention is to provide a scale inhibitor capable of preventing precipitation and adhesion of scales such as calcium ions and iron ions even in a low concentration region where the maleic acid type polymer compound cannot effectively prevent scale. Is to do.

It is another object of the present invention to provide a method for producing a maleic anhydride copolymer having an excellent scale-inhibiting effect by using a relatively small amount of a polymerization initiator.

The copolymers of maleic anhydride and olefins include copolymers of maleic anhydride and conjugated diene (Japanese Patent Publication No. 58-35205) and copolymers of maleic anhydride and α-olefin. Polymers (U.S. Pat. Nos. 3,553,177, 3,560,455, 3,560,456, and 3,560,457)
It has been known. It is known that a copolymer of maleic anhydride and an α-olefin uses a hydrolyzate as a scale inhibitor. On the other hand, a copolymer of maleic anhydride and a conjugated diene is known for use as an adhesive, a re-staining inhibitor for detergents, a dyeing aid, a quenching agent, and the like. However, it was not used as a scale inhibitor. Heretofore, a copolymer of maleic anhydride, α-olefin and conjugated diene has not been known.

The present inventors have studied to synthesize a novel copolymer of maleic anhydride, an aliphatic monoolefin and a conjugated diene as a scale inhibitor. However, a maleic anhydride-based copolymer containing a conjugated diene such as butadiene, which can be used as a scale inhibitor, has been difficult to produce only by applying a conventional method (Japanese Patent Publication No. Sho 46 (1)). No.-31972, No.47-45954,
No. 58-35205).

Accordingly, another object of the present invention is to provide a novel maleic anhydride copolymer useful as a scale inhibitor, that is, a maleic anhydride / aliphatic monoolefin / conjugated diene copolymer and a method for producing the same. Is to do.

Another object of the present invention is to provide a scale inhibitor containing a novel maleic acid copolymer which is a hydrolyzate of the above-mentioned novel maleic anhydride copolymer.

[0011]

According to the present invention, there is provided the following formula (I):
Maleic anhydride unit represented by

[0012]

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At least one conjugated diene unit represented by the following general formula (II)

[0014]

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(Wherein R ¹ R ² R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms)
And at least one aliphatic monoolefin unit represented by the following general formula (III)

[0016]

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(Wherein R ⁵ R ⁶ R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms)
And a weight average molecular weight of 500 to 5
000, and the molar ratio of the maleic anhydride unit (I) to the total of the conjugated diene unit (II) and the aliphatic monoolefin unit (III) [(I) / ((II) + (II)
I))] is in the range of 30/70 to 90/10, and the molar ratio of the conjugated diene unit (II) to the aliphatic monoolefin unit (III) [(II) / (III)] is 5/9.
It relates to a scale inhibitor comprising a maleic anhydride copolymer in the range of 5-90 / 10.

Another aspect of the present invention is to produce a scale inhibitor containing the maleic anhydride copolymer by copolymerizing maleic anhydride, a conjugated diene and an aliphatic monoolefin in the presence of a radical generator. Wherein the polymerization is carried out by continuously adding each of the conjugated diene and the aliphatic monoolefin to a mixture of maleic anhydride and an aromatic hydrocarbon solvent. The present invention relates to a method for producing a scale inhibitor containing a copolymer.

Further, the present invention provides a maleic acid unit represented by the following formula (VII):

[0020]

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(Wherein X and Y are the same or different and are selected from the group consisting of a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium and alkylammonium), at least represented by the following general formula (II) One conjugated diene unit

[0022]

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(Wherein R ¹ R ² R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms)
And at least one aliphatic monoolefin unit represented by the following general formula (III)

[0024]

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(Wherein, R ⁵ R ⁶ R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms)
And a weight average molecular weight of 500 to 5
0000, and the molar ratio of the maleic acid unit (VII) to the total of the conjugated diene unit (II) and the aliphatic monoolefin unit (III) [(VII) / ((II) + (I
II)) is in the range of 30/70 to 90/10, and the molar ratio of the conjugated diene unit (II) to the aliphatic monoolefin unit (III) [(II) / (III)] is 5 /
It relates to a scale inhibitor containing a water-soluble maleic acid copolymer in the range of 95 to 90/10.

Hereinafter, the present invention will be described in detail. In the general formula (II) which is a constitutional unit of the copolymer of the present invention, R ¹ ,
R ² , R ³ and R ⁴ are preferably each a hydrogen atom or a methyl group. The conjugated diene unit represented by the general formula (II) has 4 to 12, preferably 4 to 7, and more preferably 4 to 5 carbon atoms. Examples of conjugated diene units include butadiene, 1,3-pentadiene, isoprene,
1,3-hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene and 1,3
-Each unit of heptadiene can be exemplified. In particular, a butadiene unit is preferred because it has high reactivity with maleic anhydride, is easily available industrially, and is inexpensive.
The copolymer of the present invention may contain one kind of these conjugated diene units or two or more kinds thereof.

In the general formula (III) which is a constitutional unit of the copolymer of the present invention, R ⁵ , R ⁶ , R ⁷ and R ⁸ are each preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. . The aliphatic monoolefin unit represented by the general formula (III) has 2 to 8, preferably 2 to 5 carbon atoms. Preferred aliphatic monoolefin units are α-olefin units. Examples of the aliphatic monoolefin unit include ethylene, propylene, 1-butene, isobutene, 1-pentene, 1-hexene, 4-methyl-1-pentene,
And each unit such as -heptene and 1-octene.
The copolymer of the present invention may contain one kind of these aliphatic monoolefin units, or may contain two or more kinds thereof.

Particularly, in a copolymer containing two or more kinds of aliphatic monoolefin units and a butadiene unit as a conjugated diene unit, the hydrocarbon raw material having 4 carbon atoms in the thermal decomposition product of naphtha is used as a monomer material. It is preferable to use the amount from the viewpoint of industrial availability. The hydrocarbon fraction having 4 carbon atoms contains isobutene, 1-butene, and the like in addition to butadiene.

The copolymer of the present invention comprises a conjugated diene unit (I
The molar ratio of maleic anhydride units (I) to the sum of (I) and aliphatic monoolefin units (III) [(I) /
((II) + (III))] from 30/70 to 90/1
0, preferably in the range of 40/60 to 75/25. Further, the molar ratio of the conjugated diene unit (II) to the aliphatic monoolefin unit (III) [(II) / (I
II)] is in the range of 5/95 to 90/10, preferably in the range of 10/90 to 70/30. From the viewpoint of excellent scale prevention effect and easy production, the above range is appropriate.

Further, the weight average molecular weight of the copolymer of the present invention is from 500 to 50,000, preferably from 700 to 2,000.
0, more preferably 700 to 5000 is suitable from the viewpoint of exhibiting an excellent scale prevention effect.

The present invention also relates to a hydrolyzate of the above copolymer, that is, a maleic acid unit represented by the formula (VII), at least one conjugated diene unit represented by the general formula (II), The present invention relates to a water-soluble maleic acid copolymer containing at least one aliphatic monoolefin unit represented by (III).

The weight average molecular weight of this copolymer is 500 to 50,000, similar to the maleic anhydride copolymer.
Preferably 700 to 20,000, more preferably 700
It is suitable from the viewpoint of exhibiting an excellent scale prevention effect of from 5,000 to 5,000.

The molar ratio of the maleic acid unit (VII) to the total of the conjugated diene unit (II) and the aliphatic monoolefin unit (III) [(VII) / ((II) + (II)
I))) is preferably in the range of 30/70 to 90/10, and more preferably in the range of 40/60 to 75/25, from the viewpoint of high scale prevention effect, easy production, and excellent water solubility. Appropriate. The molar ratio [(II) / (III)] of the conjugated diene unit (II) to the aliphatic monoolefin unit (III) is in the range of 5/95 to 90/10, preferably 10/90 to 70/30. It is appropriate that the ratio is within the range because the scale prevention effect is high and the production is easy.

The maleic acid copolymer of the present invention is included in the present invention irrespective of the degree of hydrolysis as long as it is water-soluble, and the hydrolyzate of the maleic anhydride copolymer may be a completely hydrolyzed product. , Or a partial hydrolyzate. That is, the maleic acid copolymer of the present invention comprises (I)
And a maleic anhydride unit represented by the formula: Furthermore, the molar ratio of the total of the maleic acid unit (VII) and the maleic anhydride unit (I) to the total of the conjugated diene unit (II) and the aliphatic monoolefin unit (III) [((I) + (VII)) / ((II) + (II
Suitably, I))) is in the range of 30/70 to 90/10, preferably in the range of 40/60 to 75/25. Further, the molar ratio of the maleic acid unit (VII) to the maleic anhydride unit (I) [(VII) / (I)] is in the range of 10/90 to 100/0, preferably 30/70.
Suitably, it is in the range of ~ 100/0.

The water-soluble maleic acid copolymer is
Alkali metals such as sodium and potassium, calcium,
Alkaline earth metals such as barium, and salts such as ammonia and alkylamines may be used. Among them, sodium and ammonium salts are preferable.

Hereinafter, the method for producing the copolymer of the present invention will be described. The copolymer of the present invention can be produced by subjecting maleic anhydride, conjugated diene and aliphatic monoolefin to a radical copolymerization reaction in a solvent in the presence of a radical generator.

In the polymerization, the conjugated diene is preferably added continuously to a mixture of maleic anhydride and a solvent. This is because, if the conjugated diene is previously charged together with maleic anhydride and the reaction solvent, the Diels-Alder reaction proceeds during the temperature increase or at the beginning of the polymerization reaction, and the yield may decrease. By continuously supplying the conjugated diene, the polymerization reaction can be prioritized over the Diels-Alder reaction. Further, it is preferable that the aliphatic monoolefin is continuously supplied as in the case of the conjugated diene. On the other hand, the radical generator may be added in advance to a mixture of maleic anhydride and a reaction solvent, or may be added continuously like a conjugated diene.

Examples of the solvent include hydrocarbons such as benzene, toluene, xylene and cyclohexane; ketones such as acetone, cyclohexanone and methyl ethyl ketone; esters such as ethyl acetate and isopropyl acetate; ethers such as dibutyl ether, tetrahydrofuran and dioxane; Alternatively, dimethylsulfoxide, dimethylformamide, gamma-butyrolactone and the like can be used. These solvents can be classified into those in which maleic anhydride is dissolved but the copolymer is insoluble, and those in which both maleic anhydride and the copolymer are soluble. With the former type of solvent, the polymerization proceeds as a precipitation polymerization or a suspension polymerization in the presence of a suitable dispersant. On the other hand, when the latter type of solvent is used, it proceeds as solution polymerization. Solvents such as amines and alcohols are not suitable for reacting with maleic anhydride or the resulting copolymer.

Among the above-mentioned solvents, aromatic hydrocarbon solvents are preferred from the viewpoints of production and process. The aromatic hydrocarbon solvent is a poor solvent for the present copolymer, and after completion of the reaction, the copolymer precipitates and is obtained as a precipitate. Therefore, there is an advantage that most of the solvent can be easily separated by removing the supernatant, and further, unreacted maleic anhydride and by-products can be removed at the same time. Further, when producing a hydrolyzate of the copolymer, there is also an advantage that a small amount of solvent remaining in the system can be easily removed as an azeotropic mixture with water.

In the present invention, it is particularly preferable to continuously add the conjugated diene and the aliphatic monoolefin to a mixture of maleic anhydride and an aromatic hydrocarbon solvent. This is because a desired copolymer can be obtained while suppressing formation of a crosslinked polymer. At this time, the radical generator may be previously added to a mixture of maleic anhydride and an aromatic hydrocarbon solvent, or may be continuously added as in the case of the conjugated diene and the aliphatic monoolefin. .

As the aromatic hydrocarbon solvent, benzene,
Examples thereof include alkyl-substituted benzenes such as toluene, xylene, ethylbenzene and cumene, and halogen-substituted benzenes such as chlorobenzene and bromobenzene. Preferably, benzene, toluene and xylene are mentioned.

The amount of the solvent used is not particularly limited. However,
From the viewpoint of suppressing a local and rapid reaction, for example, 50 to 500 parts by weight of maleic anhydride is used.
Suitably, parts by weight of the aromatic hydrocarbon solvent are used.

Examples of the conjugated diene include butadiene, 1,3-pentadiene, isoprene, 1,3-hexadiene, 2,3-dimethyl-1,3-butadiene,
-Ethyl-1,3-butadiene, 1,3-heptadiene and the like can be used. In particular, butadiene is preferred because it has high reactivity with maleic anhydride, is easily available industrially, and is inexpensive. In the above copolymerization,
These conjugated dienes may be used alone or in combination of two or more.

As the aliphatic monoolefin, α
-Olefins are preferred. Examples of the aliphatic monoolefin include ethylene, propylene, 1-butene, isobutene, 1-pentene, 1-hexene, 1-heptene,
Examples thereof include 1-octene and 4-methyl-1-pentene. These may be used alone or as a mixture of two or more. In particular, it is industrially easily available to use a hydrocarbon fraction having 4 carbon atoms among the thermal decomposition products of naphtha as a monomer raw material containing two or more aliphatic monoolefins and containing butadiene as a conjugated diene. This is preferred. The hydrocarbon fraction having 4 carbon atoms contains isobutene, 1-butene, and the like in addition to butadiene.

A mixture of maleic anhydride and an aromatic hydrocarbon solvent or a mixture of this mixture and a radical generator previously charged in a polymerization vessel is heated to a predetermined reaction temperature. It is preferable to carry out the polymerization by continuously supplying a solution of the conjugated diene and the aliphatic monoolefin and, if desired, a radical generator. This is because if the conjugated diene, maleic anhydride and the solvent are previously charged, the Diels-Alder reaction may proceed during the temperature increase or at the beginning of the polymerization, and the yield may decrease.
By continuously supplying the conjugated diene, the polymerization reaction can be prioritized over the Diels-Alder reaction.

In the present method, the feed rates of the conjugated diene, the aliphatic monoolefin and the radical generator are not particularly limited. However, it is preferable that the feed rate of the conjugated diene satisfies the following condition from the viewpoint of suppressing the Diels-Alder reaction and suppressing the generation of an insoluble three-dimensional polymer.

Y> 175X + 80 where Y represents the reaction temperature (° C.), and X represents the butadiene feed rate (total moles of butadiene / total moles of maleic anhydride / butadiene feed time (hour)).

The conjugated diene, aliphatic monoolefin and radical generator can be supplied uniformly during the polymerization reaction, or the supply rate can be increased or decreased for controlling the reaction. .

On the other hand, when the radical generator is continuously supplied, the supply rate of the radical generator is not particularly limited. However, it is preferable that radicals are generated in accordance with the supply of the conjugated diene, and it is preferable to supply all the radical generators in substantially the same time as the supply time of the conjugated diene.
In addition, the radical generator can be supplied evenly during the polymerization reaction, or the supply rate can be increased or decreased for controlling the reaction.

The radical generator used in the present method is determined in consideration of its half-life. It is preferable to use a radical generator having a half-life of 1 hour or less in the reaction temperature range. If the half-life is too long, the amount of radicals generated per unit time will decrease, the Diels-Alder addition reaction will proceed from the polymerization reaction, leading to a decrease in yield, and it will be necessary to increase the amount of the radical generator used. Absent.

At a reaction temperature range of 90 ° C. or higher,
Examples of the radical generator having a half life of 1 hour or less include t-butylperoxy (2-ethylhexanoate),
peroxyesters such as t-butylperoxybenzoate; dialkyl peroxides such as di-t-butyl peroxide and dicumyl peroxide;
Peroxy ketals such as bis (t-butylperoxy) -3,3,5-trimethylcyclohexane can be mentioned.

The amount of the radical generator used is determined in consideration of the supply time of the radical generator and the like. For example, 0.05 to 15% by weight, preferably 0.1 to 15% by weight, based on maleic anhydride.
Suitably, it is 5 to 10% by weight. If the amount is too small, the polymerization reaction does not proceed effectively. If the amount is too large, the molecular weight is too low, and it is not preferable from an economic viewpoint.

The amounts of maleic anhydride, conjugated diene and aliphatic monoolefin used can be appropriately adjusted depending on the maleic anhydride unit, conjugated diene unit and aliphatic monoolefin unit of the copolymer.

The conjugated diene, aliphatic monoolefin and radical generator can be supplied as they are or as a mixture with a solvent. However, it is preferable to supply a mixture with a solvent from the viewpoint of suppressing a local rapid reaction. The mixing ratio (weight ratio) with the solvent is 50 to 500 parts by weight of the solvent with respect to 100 parts by weight of the conjugated diene, and 50 to 50 parts by weight of the solvent with respect to 100 parts by weight of the aliphatic monoolefin.
With respect to 500 parts by weight and 100 parts by weight of the radical generator,
It is appropriate that the solvent is used in an amount of 500 to 5000 parts by weight.

The reaction temperature is preferably 90 ° C. or higher when the radical generator is continuously supplied. If the temperature is lower than this temperature, the average molecular weight of the copolymer becomes too high than a desired value, or three-dimensional cross-linking easily occurs, and the copolymer cannot be used as a water-soluble copolymer. On the other hand, the upper limit of the reaction temperature is not particularly limited. However, in order to set the average molecular weight of the obtained copolymer to a desired value, 1 is required.
The temperature is preferably lower than 80 ° C. Considering the average molecular weight of the copolymer and the reaction time, the reaction temperature is 100 to 1
More preferably, it is in the range of 60 ° C.

The pressure is suitably normal pressure to 30 kg / cm ² G, preferably normal pressure to 10 kg / cm ² G.

After the addition of the conjugated diene, the aliphatic monoolefin and the radical generator is completed, the polymerization reaction has been almost completed.
However, in order to completely consume unreacted monomers and radical generators, it is preferable to continue the polymerization reaction for a certain period of time, for example, about 30 minutes to 2 hours.

After the completion of the reaction, the copolymer precipitated in the precipitation or suspension polymerization is recovered by filtration or decantation of the supernatant. If necessary, it can be further washed with a poor solvent. On the other hand, in solution polymerization, a copolymer is precipitated by adding a reaction solution to a large amount of a poor solvent, and the copolymer is recovered by filtration separation or decantation of a supernatant.

The copolymer thus obtained can be heated and refluxed with water for a certain period of time, or can be heated with steam to hydrolyze the copolymer to form an aqueous solution. However, from an economical and industrial point of view, it is desirable to hydrolyze using water vapor to form an aqueous solution. The operating conditions for the hydrolysis of the copolymer with steam are not particularly limited. However, the aqueous solution of the copolymer finally has a solid content of about 10 to 50% by weight.
It is preferable to adjust the amount of steam introduced and withdrawn and the amount of heating of the solution so as to obtain the following formula. In addition, the time of the hydrolysis with steam is preferably a time during which the solvent remaining in the solid content is distilled off as an azeotropic mixture at the same time as the hydrolysis, so that the solvent can be sufficiently distilled off.

Further, the aqueous solution of the hydrolyzate of the copolymer can be converted into a salt, if necessary. The compound used to make the salt is not particularly limited, and examples thereof include basic substances such as metal salts, ammonium salts and amine salts. The metal salt is sodium hydroxide,
It can be obtained by neutralizing the hydrolyzate of the copolymer using an alkali metal hydroxide or an alkaline earth metal hydroxide such as potassium hydroxide or magnesium hydroxide. Alkylamine salts include methylamine, ethylamine, aniline, cyclohexylamine, monoethanolamine,
It can be prepared using ethylenediamine or the like.
In addition, it is also possible to coexist the above-mentioned basic substance at the time of hydrolysis, to carry out the hydrolysis, and to obtain a water-soluble salt of the copolymer.

The composition ratio of the copolymer of the present invention is ¹ H-NM
It can be determined from R and ¹³ C-NMR or CHN elemental analysis. Homonuclear shift correlation NMR ( ¹ H-COS) of the copolymer
From the spectrum of Y), a 1,4-structure butadiene-
The presence of maleic anhydride units, isobutene-maleic anhydride units and 1-butene-maleic anhydride units can be confirmed. Also, from the IR spectrum, 1774 to 1780
The presence of a maleic anhydride unit can be easily confirmed by the presence of the absorption peak of the carbonyl of the cyclic acid anhydride at around 1845 to 1857 cm ^-1 . On the other hand, in the IR spectrum of the hydrolyzate of the copolymer, the absorption peak of carbonyl of the above cyclic acid anhydride becomes weak or disappears, and 171 is newly added.
Since the absorption peak of carbonyl derived from the carboxylic acid group can be observed around 4-1722 cm ^−1, the presence of the hydrolyzed maleic anhydride unit can be confirmed. ¹ H-
In the NMR spectrum, the presence of an absorption peak around 7 to 7.5 ppm confirms the presence of an aromatic terminal group due to the chain transfer reaction of the solvent. In addition, it is generally known that maleic anhydride and olefins form an alternating copolymer. In this regard, from the results of FAB-MS, it can be estimated that the copolymer of the present invention contains two or more units of maleic anhydride.

The scale inhibitor of the present invention contains the above water-soluble maleic acid copolymer. The amount of addition when the water-soluble maleic acid copolymer is used as a scale inhibitor varies depending on each ion concentration in water.
By setting the amount to 0 ppm, preferably 0.1 to 30 ppm, and more preferably 1 to 20 ppm, generation of scale can be effectively prevented.

The scale inhibitor of the present invention may use a known agent such as a water treatment agent in addition to the copolymer or a salt thereof.

[0064]

The scale inhibitor of the present invention prevents calcium ion precipitation and effectively prevents scale adhesion by adding a relatively small amount to an aqueous system. Further, the scale inhibitor of the present invention can prevent the formation of scale by effectively preventing the precipitation of iron ions by adding a small amount to the aqueous system. Further, the scale inhibitor of the present invention is derived from cations such as calcium, magnesium, iron and barium and various anions, carbonates, hydroxides, sulfates, silicates, and the like.
Generation of scale such as phosphate can be effectively prevented.

[0065]

The present invention will be further described with reference to the following examples.

Example 1 An autoclave was charged with 30 parts by weight of maleic anhydride and 48.6 parts by weight of toluene, and heated to 150 ° C. in a nitrogen atmosphere. To this, a mixed solution of 1.5 parts by weight of di-t-butyl peroxide and 40.6 parts by weight of toluene and a hydrocarbon having 4 carbon atoms obtained by thermally decomposing naphtha containing 43% of butadiene shown in Table 1 A mixed solution of 28.8 parts by weight of the fraction (12.4 parts by weight of butadiene, 7.2 parts by weight of isobutene, and 4 parts by weight of 1-butene) and 30.8 parts by weight of toluene were separately and continuously taken over 2 hours. Was added. Then 1
The reaction was aged at 50 ° C. for 1 hour to complete the reaction. After cooling the reaction solution, the supernatant was separated to obtain a block copolymer. The yield of the copolymer was 34.7 parts by weight (65% yield).

The weight average molecular weight of the obtained copolymer by GPC (gel permeation chromatography) was 7,500, and the content of maleic anhydride units estimated from CHN elemental analysis was about 59 mol%. there were. In the IR spectrum, absorption peaks of carbonyl derived from the cyclic acid anhydride were observed at around 1774 to 1780 and 1845 to 1857 cm ^-1 .

¹ H-NMR and ¹³ C of the obtained copolymer
The NMR spectra are shown in FIGS. 1 and 2, respectively. From the area ratio of these peaks, the molar ratio of (maleic anhydride unit) / (olefin unit derived from butadiene) / (other olefin unit) is 59/13/28.
Was calculated. In addition, in the ¹ H-NMR spectrum of FIG. 1, a peak derived from a benzyl group, which is an aromatic solvent residue, was observed at around 7.2 to 7.4 ppm. Further, in the ¹³ C-NMR spectrum of FIG. 2, the quaternary carbon of the t-butoxy group, which is the radical generator residue, and the primary carbon of the t-butoxy group, about ^{13 to 14} ppm, are found at around 68 to 69 ppm. Peak was observed. Furthermore, the spectrum of homonuclear shift correlation two-dimensional NMR spectra ⁽¹ H-COSY), 1,4 structure - butadiene / maleic anhydride units, isobutene / maleic anhydride units and 1-butene / maleic acid units confirmed Was done.

Next, the obtained copolymer was heated together with an appropriate amount of water in an autoclave equipped with a steam inlet tube and a condenser to introduce steam. From around 86 ° C., an azeotropic mixture of toluene and water began to agglomerate in the condenser portion, and when the temperature was raised to around 100 ° C., almost no toluene flowed out. After the temperature was raised, introduction of steam and extraction with a condenser were continued for another 2 hours, and toluene was sufficiently distilled off. The aqueous solution was cooled to room temperature to obtain 121 parts by weight of a uniform aqueous copolymer solution having a solid content of 30% by weight. In the IR spectrum of the obtained hydrolyzate,
An absorption peak of carbonyl derived from a carboxylic acid group was observed at around 1722 cm ^-1 .

Table 1 {Component Content (% by Weight)} {Butadiene 43 isobutene 25 1-butene 14 2-butene 10 butanes / others 8} ──────────

Example 2 30 parts by weight of maleic anhydride and 48.6 parts by weight of toluene were charged into an autoclave and heated to 150 ° C. in a nitrogen atmosphere. A mixed solution of 1.5 parts by weight of di-t-butyl peroxide and 40.6 parts by weight of toluene and 19.3 parts by weight of a hydrocarbon fraction having 4 carbon atoms shown in Table 1 (8.3 parts by weight of butadiene) 4.8 parts by weight of isobutene, 3.7 parts by weight of 1-butene) and 40.6 parts by weight of toluene were separately added continuously over 4 hours. Thereafter, the mixture was aged at 150 ° C. for 1 hour to terminate the reaction. After cooling the reaction solution, the supernatant was separated to obtain a block copolymer. The yield of the copolymer was 34.9 parts by weight (76% yield).
Met.

The weight average molecular weight of the obtained copolymer by GPC was 2,700, and the content of maleic anhydride units estimated from CHN elemental analysis was about 60 mol%. In the IR spectrum, 1774 to 178
At 0 and around 1845 to 1857 cm ⁻¹ , absorption peaks of carbonyl derived from the cyclic acid anhydride were observed.

As a result of ¹ H-NMR and ¹³ C-NMR, a spectrum similar to that of Example 1 was obtained. From the area ratio of these peaks, (maleic anhydride unit) / (olefin unit derived from butadiene) The molar ratio of) / (other olefin units) was calculated to be 60/12/28.

Further, hydrolysis and steam distillation were carried out in the same manner as in Example 1 to obtain 122 parts by weight of a uniform aqueous copolymer solution having a solid content of 30% by weight. In the IR spectrum of the obtained hydrolyzate, 1714 to 1722 cm ⁻¹
In the vicinity, an absorption peak of carbonyl derived from the carboxylic acid group was observed.

Example 3 100 parts by weight of maleic anhydride and 277 parts by weight of toluene were charged into an autoclave and heated to 150 ° C. in a nitrogen atmosphere. A mixed solution of 5 parts by weight of di-t-butyl peroxide and 79 parts by weight of toluene and 32 parts by weight of a hydrocarbon fraction having 4 carbon atoms shown in Table 1 (13.8 parts of butadiene) were added thereto.
Parts by weight, isobutene 8 parts by weight, 1-butene 4.5 parts by weight) and toluene 44 parts by weight were separately added over 4 hours. Thereafter, the reaction was aged at 150 ° C. for 1 hour to complete the reaction. After cooling the reaction solution, the supernatant was separated to obtain a block copolymer. The yield of the copolymer was 11
It was 6 parts by weight (yield 92%).

The weight average molecular weight of the obtained copolymer by GPC was 1,400, and the content of maleic anhydride units estimated from CHN elemental analysis was about 68 mol%. In the IR spectrum, 1774 to 178
At 0 and around 1845 to 1857 cm ⁻¹ , absorption peaks of carbonyl derived from the cyclic acid anhydride were observed.

As a result of ¹ H-NMR and ¹³ C-NMR, a spectrum similar to that of Example 1 was obtained. From the area ratio of these peaks, (maleic anhydride unit) / (olefin unit derived from butadiene) The molar ratio of) / (other olefin units) was calculated to be 68/5/27.

Further, hydrolysis and steam distillation were carried out in the same manner as in Example 1 to obtain 406 parts by weight of a uniform aqueous copolymer solution having a solid content of 30% by weight. In the IR spectrum of the obtained hydrolyzate, 1714 to 1722 cm ⁻¹
In the vicinity, an absorption peak of carbonyl derived from the carboxylic acid group was observed.

FIG. 3 shows the spectrum of FAB-MAS in the region where the molecular weight of the hydrolyzate is 1000 or less. ^Since the presence of a benzyl group as an aromatic solvent residue was confirmed from ¹ H-NMR, TM3IB, TM3
4IB, TM4I2B, TM4IB2, TM5I2B,
A chain having a composition such as TM5IB2, TM5I3B, and TM5I2B2 was confirmed. The composition of TM was confirmed by high resolution measurement. (T is benzyl, M is maleic acid,
I represents isobutene or 1-butene, and B represents a butadiene unit. )

Example 4 125 parts by weight of maleic anhydride and 377 parts by weight of toluene were charged into an autoclave and heated to 140 ° C. in a nitrogen atmosphere. This is followed by t-butyl peroxybenzoate6.
A mixed solution of 25 parts by weight and 79 parts by weight of toluene, and Table 1
A mixed solution of 120 parts by weight of a hydrocarbon fraction having 4 carbon atoms (butadiene 51.6 parts by weight, 30 parts by weight of isobutene, 16.8 parts by weight of 1-butene) and 44 parts by weight of toluene was separately taken for 3 hours. Was added continuously. afterwards,
The reaction was aged at 140 ° C. for 1 hour to complete the reaction. After cooling the reaction solution, the supernatant was separated to obtain a block copolymer. The yield of the copolymer was 149 parts by weight (67% yield).

The weight average molecular weight of the obtained copolymer by GPC was 5,800, and the content of maleic anhydride units estimated from CHN elemental analysis was about 57 mol%. In the IR spectrum, 1774 to 178
At 0 and around 1845 to 1857 cm ⁻¹ , absorption peaks of carbonyl derived from the cyclic acid anhydride were observed.

As a result of ¹ H-NMR and ¹³ C-NMR, a spectrum similar to that of Example 1 was obtained. From the area ratio of these peaks, (maleic anhydride unit) / (olefin unit derived from butadiene) The molar ratio of) / (other olefin units) was calculated to be 57/12/31.

Further, hydrolysis and steam distillation were carried out in the same manner as in Example 1 to obtain 522 parts by weight of a uniform aqueous copolymer solution having a solid content of 30% by weight. In the IR spectrum of the obtained hydrolyzate, 1714 to 1722 cm ⁻¹
In the vicinity, an absorption peak of carbonyl derived from the carboxylic acid group was observed.

Example 5 30 parts by weight of maleic anhydride and 48.6 parts by weight of toluene were charged into an autoclave and heated to 132 ° C. in a nitrogen atmosphere. To this was added t-butyl peroxybenzoate.
A mixed solution of 5 parts by weight and 40.6 parts by weight of toluene, and 19.8 parts by weight of a hydrocarbon fraction having 4 carbon atoms shown in Table 1 (8.5 parts by weight of butadiene, 5 parts by weight of isobutene, and 2 parts of 1-butene). (8 parts by weight) and 30.8 parts by weight of toluene were separately added continuously over 2 hours. Thereafter, the mixture was aged at 132 ° C. for 1 hour to terminate the reaction. After cooling the reaction solution, the supernatant was separated to obtain a block copolymer. The yield of the copolymer was 32.8 parts by weight (yield 71%)
Met.

The weight average molecular weight of the obtained copolymer by GPC was 4,200, and the content of maleic anhydride units estimated from CHN elemental analysis was about 61 mol%. In the IR spectrum, 1774 to 178
At 0 and around 1845 to 1857 cm ⁻¹ , absorption peaks of carbonyl derived from the cyclic acid anhydride were observed.

¹ H-NMR and ¹³ C-NMR of the obtained copolymer
The NMR spectra are the same as in FIGS. 1 and 2, respectively. From the area ratio of these peaks, the molar ratio of (maleic anhydride unit) / (olefin unit derived from butadiene) / (other olefin unit) is as follows. , 6
It was calculated to be 1/11/28.

Further, hydrolysis and steam distillation were carried out in the same manner as in Example 1 to obtain 115 parts by weight of a uniform aqueous copolymer solution having a solid content of 30% by weight. In the IR spectrum of the obtained hydrolyzate, 1714 to 1722 cm
An absorption peak of carbonyl derived from the carboxylic acid group was observed around ^-1 .

Examples 6 to 17 Copolymers were obtained in the same manner as in Example 1 using the conditions shown in Table 2. Table 2 shows the results such as the yield and the molecular weight. still,
The generator of Example 12 and the supply time of “0 hr” means that the generator was previously contained in a mixture of maleic anhydride and an aromatic hydrocarbon solvent.

Examples 18 to 20 Copolymers were obtained in the same manner as in Example 3 using the conditions shown in Table 2. Table 2 shows the results such as the yield and the molecular weight.

[0090]

[Table 2]

In Table 2, MAn is maleic anhydride, BD is butadiene, IP is isoprene, IB is isobutene, B
1 is 1-butene, PB-D is di-t-butyl peroxide, PB-Z is t-butyl peroxybenzoate,
PB-O indicates t-butylperoxy (2-ethylhexanoate), and PH-3M indicates 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane. The unit of the amount of the radical generator added is% by weight (based on the weight of maleic anhydride), and the unit of the half-life is time.

Example 21 3000 parts by weight of maleic anhydride and 25200 parts by weight of toluene were charged into an autoclave and heated at 150 ° C. in a nitrogen atmosphere.
Until heated. A mixed solution of 150 parts by weight of di-t-butyl peroxide and 7200 parts by weight of toluene and 960 parts by weight of a hydrocarbon fraction having 4 carbon atoms shown in Table 1 (412 parts by weight of butadiene, 240 parts by weight of isobutene, 1 part by weight) −
A mixed solution of 134.1 parts by weight of butene and 3600 parts by weight of toluene was separately added over 4 hours. Thereafter, the reaction was aged at 150 ° C. for 1 hour to complete the reaction. After cooling the reaction solution, the supernatant was separated to obtain a block copolymer.
The yield of the copolymer was 2,490 parts by weight (66% yield).

The weight average molecular weight of the obtained copolymer by GPC was 1,000, and the content of maleic anhydride units estimated from CHN elemental analysis was about 56 mol%.

Further, hydrolysis and steam distillation were carried out in the same manner as in Example 1 to obtain 8,715 parts by weight of a uniform aqueous copolymer solution having a solid content of 30% by weight.

Example 22 An autoclave was charged with 1,000 parts by weight of maleic anhydride and 7,500 parts by weight of toluene, and heated to 135 ° C. in a nitrogen atmosphere. To this, a mixed solution of 50 parts by weight of t-butyl peroxybenzoate and 1500 parts by weight of toluene, and 640 parts by weight of a hydrocarbon fraction having 4 carbon atoms shown in Table 1 (275.2 parts by weight of butadiene, 160 parts by weight of isobutene,
A mixed solution of 19.6 parts by weight of 1-butene) and 3000 parts by weight of toluene was separately added over 3 hours. Thereafter, the reaction was aged at 135 ° C. for 1 hour to terminate the reaction. After cooling the reaction solution, the supernatant was separated to obtain a block copolymer. The yield of the copolymer was 1143 parts by weight (75% yield).
Met.

The weight average molecular weight of the obtained copolymer by GPC was 4,700, and the content of maleic anhydride units estimated from CHN elemental analysis was about 47 mol%.

Further, hydrolysis and steam distillation were carried out in the same manner as in Example 1 to obtain 4000 parts by weight of a uniform aqueous copolymer solution having a solid content of 30% by weight.

Example 23 915 parts by weight of a hydrocarbon fraction having 4 carbon atoms shown in Table 1 (393.5 parts by weight of butadiene, 22 parts by weight of isobutene 22
A copolymer was obtained in the same manner as in Example 22, except that 8.8 parts by weight and 128.1 parts by weight of 1-butene were used. The yield of the copolymer was 1124 parts by weight (64% yield).

The weight average molecular weight of the obtained copolymer by GPC was 15,700, and the content of maleic anhydride units estimated from CHN elemental analysis was about 48 mol%.

Further, hydrolysis and steam distillation were carried out in the same manner as in Example 1 to obtain 3934 parts by weight of a uniform aqueous copolymer solution having a solid content of 30% by weight.

Example 24 100 parts by weight of maleic anhydride and 296 of cyclohexanone
Charge the autoclave to 100 parts by weight in a nitrogen atmosphere.
Heated to ° C. 10 parts by weight of t-butylperoxy (2-ethylhexanoate) and 9 parts of cyclohexanone
2 parts by weight of the mixed solution, and 41.7 parts by weight of isoprene,
Mixed solutions of 22.9 parts by weight of isobutene and 12 parts by weight of cyclohexanone were separately added continuously over 3 hours. Thereafter, the reaction was aged at 100 ° C. for 1 hour to terminate the reaction. After cooling to room temperature, the reaction solution was poured into excess toluene to precipitate a copolymer, which was separated by filtration, washed and dried to obtain 136 parts by weight of a copolymer (yield 83).
%). Further, the copolymer was hydrolyzed with an aqueous sodium hydroxide solution to obtain a uniform aqueous copolymer solution having a solid content of 30% by weight.

Test Example (Scale adhesion suppression test) 900 ml of tap water in a beaker
, And various copolymers or commercial products are added so that the final solid content concentration becomes 1.5 ppm or 20 ppm, and a calcium chloride dihydrate 5.88 wt% aqueous solution 20 m
1 and 20 ml of a 0.70% by weight aqueous solution of Mohr's salt were added. Adjust the pH to 8.5 with aqueous sodium hydroxide,
Tap water was added to bring the total volume to 11. The beaker was placed in a constant temperature water bath at 40 ° C., and the pipe heater was immersed in the test solution in the beaker to adjust the liquid temperature to 60 ° C. After 6 hours, the amount of scale attached to the pipe heater was weighed. The scale adhesion inhibition rate (%) was calculated from the amount of adhesion by the following formula. The results are shown in Table 3.

Scale adhesion inhibition rate (%) = ((BA) / B) × 100 A: Scale adhesion amount after test B: Scale adhesion amount without addition

(Iron-Scale Precipitation Inhibition Test) 500 ml of pure water was placed in an Erlenmeyer flask, and various copolymers or commercial products were added so that the final solid concentration was 2.5 ppm.
Further, 10 ml of a 0.70% by weight aqueous solution of Mohr salt and 10 ml of a 3.36% by weight aqueous solution of sodium hydrogen carbonate were added. Adjust the pH to 8.5 with aqueous sodium hydroxide,
Pure was added to bring the total volume to 11. The Erlenmeyer flask was capped and allowed to stand in a constant temperature water bath at 40 ° C. for 20 hours. Then
Allow to cool to room temperature, collect supernatant, and determine iron concentration by ICP
Was analyzed by The scale precipitation inhibition rate (%) was calculated by the following formula. The results are shown in Table 3.

Scale deposition inhibition rate (%) = ((AB) / (CB)) × 100 A: Iron concentration in supernatant after test B: Iron concentration in supernatant after test without addition C: Iron concentration before test

[0106]

[Table 3]

Reference Production Example 1 An autoclave was charged with 25 parts by weight of maleic anhydride and 69 parts by weight of toluene, and heated to 150 ° C. in a nitrogen atmosphere. A mixed solution of 0.5 parts by weight of di-t-butylperoxyside and 20.5 parts by weight of toluene and a mixed solution of 7.1 parts by weight of isobutene and 10.5 parts by weight of toluene were separately added for 2 hours. And added. Then 150
The reaction was completed by aging at 1 ° C. for 1 hour. After cooling the reaction solution, the supernatant was separated and subjected to hydrolysis and steam distillation to obtain 73 parts by weight of a homogeneous aqueous solution of a copolymer hydrolyzate having a solid content of 30% by weight.

[Brief description of the drawings]

[1] ¹ H-NM maleic anhydride copolymer of the present invention
1 shows the spectrum of R.

FIG. 2 shows the ¹³ C-NM of the maleic anhydride copolymer of the present invention.
1 shows the spectrum of R.

FIG. 3 shows a spectrum of FAB-MS in a region where the molecular weight of the maleic acid copolymer (hydrolyzate) of the present invention is 1,000 or less.

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C08F 236: 04 C08F 236: 04 210: 08) 210: 08) (72) Inventor Yasushi Takano 3-chome Shiroyama, Toinmachi, Inaba-gun, Mie Prefecture. 23-1 No. 1 (72) Inventor Masao Ishii 4-5-16-1 Sumiyoshi, Suzuka-shi, Mie (72) Inventor Yoshiaki Kano 2-1504-67 Miyukigaoka, Yokkaichi-shi, Mie (56) References 237045 (JP, A) JP-A-51-157189 (JP, A) JP-A-4-65408 (JP, A) JP-B-49-29124 (JP, B1) (58) Fields investigated (Int. ⁷ , DB name) C08F 222/00-222/40 C08F 210/00-210/18 C08F 236/00-236/22 CA (STN) REGISTRY (STN)

Claims (5)

(57) [Claims] 1. A maleic anhydride unit represented by the following formula (I): At least one conjugated diene unit represented by the following general formula (II): Wherein R ¹ R ² R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; Olefin unit Wherein R ⁵ R ⁶ R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and have a weight average molecular weight of 500 to 50,000; Maleic anhydride unit (I) based on the sum of conjugated diene unit (II) and aliphatic monoolefin unit (III)
Is 30 [(I) / ((II) + (III))].
/ 70 to 90/10, and the molar ratio of the conjugated diene unit (II) to the aliphatic monoolefin unit (III) [(II) / (III)] is 5/95 to 90/10
A scale inhibitor containing a maleic anhydride copolymer in the range of 2. The conjugated diene unit represented by the general formula (II) is a butadiene unit represented by the formula (IV): An aliphatic monoolefin unit represented by the general formula (III) is an isobutene unit represented by the formula (V): And a 1-butene unit represented by the formula (VI): The scale inhibitor according to claim 1, which is at least one member selected from the group consisting of: 3. A maleic acid unit represented by the following formula (VII): (Wherein X and Y are the same or different and are selected from the group consisting of hydrogen atom, alkali metal, alkaline earth metal, ammonium and alkylammonium), and at least one of the following general formula (II) Conjugated diene unit (Wherein, R ¹ R ² R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms), and at least one kind of an aliphatic monomer represented by the following general formula (III) Olefin unit Wherein R ⁵ R ⁶ R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and have a weight average molecular weight of 500 to 50,000; Maleic acid unit (VII) based on the sum of conjugated diene unit (II) and aliphatic monoolefin unit (III)
The molar ratio [(VII) / ((II) + (III))] is in the range of 30/70 to 90/10, and the conjugated diene unit (II) to the aliphatic monoolefin unit (III)
Is from 5/95 to 90 /
10. A scale inhibitor comprising a water-soluble maleic acid copolymer in the range of 10. 4. A maleic anhydride unit represented by the following formula (I): And the molar ratio of the total of maleic acid units (VII) and maleic anhydride units (I) to the total of conjugated diene units (II) and aliphatic monoolefin units (III) [((I) + (VII) ) / ((II) + (II
The scale inhibitor according to claim 3, wherein (I))) is in the range of 30/70 to 90/10. Presence of 5. A radical generator include maleic anhydride, a conjugated diene and an aliphatic mono-olefin are copolymerized claim 1 maleic acid copolymer according scale
A method for producing an antioxidant , characterized in that polymerization is performed by continuously adding each of the conjugated diene and the aliphatic monoolefin to a mixture of maleic anhydride and an aromatic hydrocarbon solvent. Containing maleic anhydride copolymer
A method for producing a scale inhibitor .