JPH0457811A - Production of aqueous solution or slurry of metal salt of maleic anhydride copolymer - Google Patents

Abstract

PURPOSE:To produce easily and inexpensively an aqueous solution or slurry of a metal salt of a maleic anhydride copolymer by copolymerizing maleic anhydride with a copolymerizable vinyl monomer in a specified organic solvent, adding a metal (hydr)oxide and water to reaction mixture, and reaction them under heating while distilling off the organic solvent. CONSTITUTION:Maleic anhydride is copolymerized with at least one vinyl monomer copolymerizable therewith (e.g. styrene) in an organic solvent which can dissolve these monmers but cannot dissolve the obtained copolymer (e.g. toluene). A metal hydroxide or a metal oxide (e.g. ZnO) and water are added to the obtained copolymer slurry and reacted under heating while distilling off the organic solvent. In this way, an aqueous solution or slurry of a metal salt of a maleic anhydride copolymer is obtained. The obtained aqueous solution or slurry can desirably be used as an adhesive, a nonburning coating agent, a cement dispersing agent or the like.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for producing an aqueous solution or aqueous slurry of a maleic anhydride copolymer metal salt, and more specifically relates to an inorganic dispersant, an adhesive, an adhesive, and a method for producing an aqueous slurry. The present invention relates to a method for obtaining an aqueous solution or aqueous slurry of a maleic anhydride copolymer metal salt useful as a rust agent, a noncombustible coating agent, a water absorbing agent, a cement dispersant, etc., using an unprecedented and simple means.

[Prior art and problems to be solved by the invention] Copolymers of lower olefins and maleic anhydride are sometimes stored and used in the form of dispersion in water; During this process, a mild hydrolysis reaction occurs in water, causing changes in physical properties and properties. For this reason, a technology has been developed in which the maleic anhydride copolymer is made to react with metal oxide or metal hydroxide to stabilize it without changing its physical properties and properties even after long-term storage (Japanese Patent Laid-Open No. 62-83344). Public bulletin).

Maleic anhydride copolymer metal salts have conventionally been used as inorganic dispersants (JP-A-60-993) in the form of aqueous solutions or aqueous slurries.
No. 34), adhesive composition (JP-A-59-12064)
7), rust preventive agents (JP-A-51-147441), non-flammable coating agents (JP-A-52-99699), water-absorbing agents (JP-A-59-230046, JP-A-59- No. 125973), cement dispersant (Japanese Unexamined Patent Publication No. 62-83344), etc.

Generally, as a method for obtaining an aqueous solution or aqueous slurry of a maleic anhydride copolymer metal salt, after polymerization, the solvent used in the polymerization is removed, and the copolymer powder is reacted with a metal oxide or metal hydroxide in water. A method is taken to make it happen. but,
This synthesis method requires a large amount of energy for drying.
Further, the adhesion of the copolymer to the inner wall of the dryer causes a decrease in yield, and above all, there is a major drawback in that powder must be handled.

[Means to solve the problem]

As a result of intensive research to solve the above-mentioned conventional drawbacks, the present inventors discovered that after polymerization, water and metal hydroxide or metal oxide were directly added without removing the solvent, and the polymerization solvent was added while the reaction was occurring. The present invention was completed based on the discovery that an aqueous solution or aqueous slurry of a maleic anhydride copolymer metal salt can be obtained without a drying step by removing it.

That is, the present invention provides maleic anhydride and one or more vinyl monomers copolymerizable with maleic acid in an organic solvent that dissolves these monomers but does not dissolve the resulting copolymer. A maleic anhydride copolymer metal salt is characterized in that a metal hydroxide or a metal oxide and water are added to the resulting copolymer slurry and the organic solvent is distilled off while the reaction is heated. The present invention provides a method for producing an aqueous solution or aqueous slurry.

The present invention will be explained in detail below.

Vinyl monomers copolymerizable with maleic anhydride used in the present invention include olefins having 2 to 22 carbon atoms, styrene monomers, alkyl vinyl ethers having alkyl groups having 1 to 22 carbon atoms, and Examples include vinyl esters of 2 to 22 aliphatic carboxylic acids.

Specific examples of olefins having 2 to 22 carbon atoms include ethylene, propylene, isobutylene, 1-butene, 2-butene, 1-pentene, 2-pentene, 1-hexene, cyclopentene, 2-methyl-17-butene, cyclohexene, - Straight chain or branched, such as methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-butene, diisobutylene, 1-decene, 1-dodecene, 1-octadecene, etc. Examples include olefins.

Specific examples of the styrene monomer include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, chloromethylstyrene, and the like.

Examples of the alkyl vinyl ether having an alkyl group having 1 to 22 carbon atoms include methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, lauryl vinyl ether, and stearyl vinyl ether.

Examples of vinyl esters of aliphatic carboxylic acids having 2 to 22 carbon atoms include vinyl acetate, vinyl propionate, vinyl laurate, vinyl stearate, and the like.

Among those exemplified above, lower olefins having 2 to 8 carbon atoms, styrene monomers, and lower alkyl vinyl ethers having alkyl groups having 1 to 4 carbon atoms are preferably used, and isobutylene and styrene are particularly preferred.

In the present invention, the molar ratio of maleic anhydride to the vinyl monomer copolymerizable with it (if two or more types are used, their total il) is preferably in the range of 172 to 2/1. , more preferably in the range of 1/1.2 to 1.2/1.

In the present invention, the organic solvent used to synthesize the copolymer is not particularly limited as long as it dissolves the monomers used in the reaction but does not dissolve the resulting copolymer. In particular, solvents that have a lower boiling point than water or are azeotropic with water are preferred, and specific examples include aromatic solvents such as benzene, xylene, toluene, ethylbenzene, n- or t-butylbenzene, and isopropylbenzene that are azeotropic with water. system solvent,
Examples include lower ester solvents such as methyl acetate, ethyl acetate, isopropyl acetate, and methyl propionate, and ketone solvents such as acetone, methyl ethyl ketone, and diethyl ketone. These may be used alone or in combination of two or more. The amount of these solvents is preferably such that the concentration of the resulting copolymer is 5 to 35% by weight.

In the present invention, precipitation polymerization is carried out using maleic anhydride and a vinyl monomer copolymerizable with maleic anhydride in accordance with a conventional method in the presence of a radical polymerization initiator in an organic solvent as described above. Obtain a combined slurry.

Examples of radical polymerization initiators include cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, diisopropyl peroxycarbonate, lauroyl)<-oxide, t-butyl peroxybenzoate, potassium persulfate, and ammonium persulfate. oxides, azo initiators such as 2.2''-azobisisobutyronitrile, 2.2'-azobis(2,4-dimethylvaleronitrile), etc., but are particularly limited to these. isn't it.

The amount of these polymerization initiators used is based on maleic anhydride.
0.1-20 mol% is suitable.

The polymerization temperature is selected depending on the decomposition temperature of the polymerization initiator used and the boiling point of the solvent used, but is usually 30 to 1
It is carried out at 50°C, preferably in the range of 40 to 100°C. If the polymerization temperature is too low, the polymerization rate will decrease, and if it is too high, the produced copolymer will tend to adhere to the reactor wall or form lumps.

The time for the polymerization reaction is normally set appropriately within the range of 1 to 15 hours.

Furthermore, the reaction may be carried out under pressure, or may be carried out under normal pressure by dropping the vinyl monomer as it is or as a solution, or by blowing in the vinyl monomer if it is a gaseous monomer. .

In the present invention, the metal hydroxide or metal oxide and water are directly added to the copolymer slurry obtained as described above without removing the organic solvent used in the synthesis of the copolymer. The organic solvent is distilled off while the reaction is heated. The metal hydroxides and metal oxides used here include metals that can react with maleic anhydride to form salts, such as Na+ K+ Ca, Cu, Zn+ N
Examples include hydroxides and oxides containing metals such as i+Mg+AI+Fe and Tt. These may be used alone or in combination of two or more, but copper oxide, zinc oxide, copper hydroxide, and zinc hydroxide are particularly preferred. The molar ratio of these metal hydroxides or metal oxides to maleic anhydride is desirably within the range of metal hydroxide or metal oxide/maleic anhydride=0.5 to 2, more preferably 0. .8-1.
It is within the range of 2.

When using a hydroxide or oxide containing a monovalent alkali metal, such as Na, K, etc., the metal salt of the copolymer is finally obtained in the form of an aqueous solution. Further, when a divalent or higher valent metal is used, such as Ca, Cu, Zn, Ni, Mg, etc., the metal salt of the copolymer can be obtained in the form of an aqueous slurry dispersed in water.

In the synthesis method of the present invention, when a hydroxide or oxide containing a divalent or higher metal is used, the metal salt is added while maintaining the particle size and particle shape of the copolymer obtained by precipitation polymerization. It is particularly useful because it can be obtained.

In the present invention, the reaction temperature when adding a metal hydroxide or a metal oxide and water to the maleic anhydride copolymer slurry and reacting is determined by It is selected according to the boiling point of the solvent or the azeotropic temperature of the organic solvent and water, but usually 30 to 1
The temperature is preferably 60 to 100°C.

If the reaction temperature is too low, the reaction rate will decrease, and if it is too high, the copolymer metal salt produced will tend to adhere to the reactor wall or form lumps.

Moreover, this temperature may be changed during the reaction as necessary. The reaction time is affected by the reaction temperature, but is usually 1 to 20
It is set appropriately within the time range.

The amount of water to be added is such that all the organic solvent is azeotroped and the remaining aqueous solution or slurry of the copolymer metal salt has a concentration of 5 to 60%.
It is adjusted to be 20 to 40% by weight, preferably 20 to 40% by weight.

〔Example〕

The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples. In addition, "parts" in the examples are "parts by weight j".

Example-1 A 11 separable flask equipped with a stirring device, a gas inlet pipe, a thermometer, and a cooling pipe, with a gas bag attached to the end of the cooling pipe, was equipped with 607 parts of toluene, 68.6 parts of maleic anhydride, and ethyl cellulose [Vercules]. manufactured by Ethyl Cellulose N
-7, ethoxyl content 48%, molecular weight 62,000
3.4 parts (in terms of cm listyrene) were added, and the temperature was raised to 70°C with stirring in a nitrogen atmosphere. As a polymerization initiator, 2
, 2'-azobisisobutyronitrile (6.8 parts) was added, and then isobutylene gas was introduced into the solution from a gas inlet tube from a separately prepared cylinder. While the reaction temperature was maintained at 70°C, 45 parts of isobutylene gas (molar ratio to maleic anhydride: 1.14) was continuously blown in over 3 hours. After the introduction of isobutylene gas, the solution immediately became cloudy and the gas bag did not inflate, indicating that the gas was efficiently absorbed into the solution and a polymerization reaction was occurring.

After the completion of gas blowing, the mixture was further aged at that temperature for 2 hours with stirring, and then cooled to obtain a toluene slurry of isobutylene maleic anhydride copolymer.

362.5 parts of the toluene slurry of the obtained isobutylene maleic anhydride copolymer, 28.5 parts of zinc oxide in an equimolar amount to the maleic anhydride unit in the copolymer, and 199.5 parts of ion-exchanged water were mixed using a stirring device and temperature. 11 equipped with a water meter and a dehydration pipe.
I put it in a separable flask. The temperature of the reaction bath is 110°.
The temperature was raised to C, and while the reaction between the isobutylene maleic anhydride copolymer and zinc oxide proceeded, toluene, which was a polymerization solvent, was distilled off azeotropically with water. The azeotrope was carried out at 85°C, and the fraction composition was toluene:water=80:20.

Distillation of toluene, the polymerization solvent, was completed in about 4 hours, and the toluene slurry could be directly transferred to a water slurry.

In addition, absorption of anhydride groups was measured by infrared spectroscopy, but could hardly be confirmed.

It is considered that the reaction between the isobutylene maleic anhydride copolymer and zinc oxide progresses quantitatively.

Examples 2 to 5 Same as Example 1 except that the polymerization solvent and metal oxide or metal hydroxide shown in Table 1 are used instead of toluene and zinc oxide as polymerization solvents in Example 1. The reaction was carried out.

In Example-2, a transparent aqueous solution of the copolymer metal salt was obtained. In Examples 3 to 5, water slurries in which copolymer metal salts were dispersed in water were obtained.

Completion of the reaction was confirmed by infrared spectrum measurement in the same manner as in Example-1.

Table-1 Example 6 Styrene 72 instead of isobutylene gas in Example-1
．． A toluene slurry of styrene maleic anhydride copolymer was obtained in the same manner as in Example 1, except that 8 parts (molar ratio to maleic anhydride: 1.0) was continuously added dropwise over 3 hours.

396.1 parts of toluene slurry of the obtained styrene-maleic anhydride copolymer, 28.5 parts of zinc oxide in an equimolar amount to the maleic anhydride unit of the copolymer, and 199 parts of ion-exchanged water.
．． The reaction was carried out in the same manner as in Example-1 using 5 parts.

Distillation of toluene was completed in about 4 hours, and a copolymer water slurry was obtained.

From the results of infrared spectrum measurements, it was confirmed that the reaction between the copolymer and zinc oxide was complete.

Comparative Example-1 A toluene slurry of isobutylene maleic anhydride copolymer synthesized in the same manner as in Example-1 was filtered and dried at 80°C under a reduced pressure of 100 Hg. It took about 6 hours. Also, adhesion of copolymer was observed inside the kneader/dryer. The yield was 95% based on maleic anhydride.

67.2 parts of the obtained copolymer, 35.5 parts of zinc oxide, and 154.1 parts of ion-exchanged water were placed in a 500 Ml separable flask and reacted at 80°C. When the absorption of the anhydride group was followed by infrared spectroscopy, it took about 7 hours for it to disappear.

〔Effect of the invention〕

As explained in detail above, according to the method of the present invention, a dryer is not required, so 1) fixed costs are reduced, 2) energy required for drying is not required, 2) cycle time is shortened, and 3 there is no powder handling. ■Since there is no adhesion of the copolymer to the inner wall of the dryer, it has the advantage of preventing a decrease in yield.

Therefore, not only can the cost of the product be reduced, but also the stability of production can be improved because the operation is simple.

Claims (1)

[Claims] 1. Maleic anhydride and one or more vinyl monomers copolymerizable with maleic acid, these monomers dissolve, but the resulting copolymer does not dissolve. A maleic anhydride copolymer characterized by polymerizing in an organic solvent, adding a metal hydroxide or a metal oxide and water to the obtained copolymer slurry, and distilling off the organic solvent while carrying out a heating reaction. A method for producing an aqueous solution or slurry of a combined metal salt. 2. The method for producing an aqueous solution or slurry of a maleic anhydride copolymer metal salt according to claim 1, wherein the organic solvent has a boiling point lower than that of water or is an azeotrope with water. 3. The method for producing an aqueous solution or slurry of a maleic anhydride copolymer metal salt according to claim 1, wherein the metal hydroxide or metal oxide is a hydroxide or oxide of zinc or copper.