JPS6215203A - Reactive dispersant for reversed phase suspension polymerization - Google Patents

Abstract

PURPOSE:A dispersant capable of improving extremely productivity of a polymer when it is used for reversed phase suspension polymerization of a water-soluble ethylenic unsaturated monomer, comprising a specific phosphoric monoester compound containing an ethylenic unsaturated bond in the molecule. CONSTITUTION:A compounding having a structure shown by the formula I (R1 is H or CH3; R2 is 4-12C alkyl; M is H, alkali metal or ammonium) is used as the aimed dispersant. The compound shown by the formula I, for example, is preferably obtained by reacting a monoalkali metallic salt of a monoalkyl phosphate shown by the formula II (M' is alkali metal) with a glycidyl (meth) acrylate shown by the formula III (M' is alkali metal) to give a phosphoric ester, acidifying optionally the ester and neutralizing it with a base and a compound shown by the formula IV, formula V, etc., may be used.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for performing reverse phase suspension polymerization by adding an aqueous solution of a water-soluble ethylenically unsaturated monomer to a polymerization inert and hydrophobic solvent. The present invention relates to a dispersant used for, in particular, a reactive dispersant that can be copolymerized with a polymerizable monomer.

[Conventional technology]

As a method for polymerizing water-soluble ethylenically unsaturated monomers, a so-called reverse-phase suspension polymerization method is well known, in which the monomers are suspended and dispersed in a hydrophobic solvent and polymerized. In implementing this method, it is important to accurately select a dispersant that can completely stabilize the monomer to be polymerized and prevent or reduce agglomeration of polymer particles. In other words, by selecting a suitable dispersant, productivity can be significantly improved and a polymer with uniform physical properties can be obtained.

Examples of dispersants used in reverse-phase suspension polymerization of water-soluble ethylenically unsaturated monomers include non-containing agents such as sorbitan monostearate, sorbitan monooleate, ethoxylated fatty acid amides, and glycerin fatty acid esters. Ionic surfactants are known (Japanese Patent Publication No. 54-30710
Publications, etc.).

In addition to the above, for example, resins having allyl (^ttyt) groups treated with maleic acid, polymers containing carboxyl groups that have affinity for organic solvents, lipophilic cellulose derivatives, etc. Molecular compounds and the like are known (Japanese Unexamined Patent Publication No. 57-74309, etc.).

[Problem that the invention seeks to solve]

However, in the -10 suspension polymerization method using these dispersants, the dispersant remains in the solvent after polymerization, and when the polymerization process is continuously operated, the remaining dispersant As a result, the polymerization system becomes unstable, causing problems such as gelation of the polymer. Therefore, since it is necessary to purify the solvent after several polymerizations, a decrease in polymer production efficiency is unavoidable.

In addition, when nonionic surfactants or polymeric dispersants are used, these dispersants are adsorbed on the surface of the hydrophilic resin. When used, due to stickiness, polymer particles adhere as aggregates to the walls of the polymerization tank or to the stirrer during the polymerization operation, resulting in a significant portion of the reacted xL polymer becoming unusable. It is inevitable that it will be lost as deposits in the tank. Generally, it takes a great deal of effort to remove water-soluble ethylenically unsaturated monomers deposited in a polymerization tank, which hinders efficient production of particulate polymers.

[Means for solving problems]

As a result of intensive research to solve the above-mentioned problems, the present inventors achieved the desired results by using a phosphoric acid monoester compound having an ethylenically unsaturated bond in the molecule as a dispersant for suspension polymerization of 10. The present invention was completed based on the discovery that the object can be achieved.

That is, the present invention is based on the general formula (I) % formula % (in the formula, R8 is H or CH:l, Rz is an alkyl group having 4 to 12 carbon atoms, and H represents H, an alkali metal, or ammonium). The present invention provides a reactive dispersant for reverse phase suspension polymerization comprising a compound having the structure shown below.

The reactive dispersant for reverse-phase suspension polymerization of the present invention can be produced, for example, as follows. That is, a monoalkali metal salt of a monoalkyl phosphoric acid represented by the formula (II) is reacted with glycidyl methacrylate or glycidyl acrylate represented by the formula (III) to produce a phosphate ester, and if necessary acidified and further treated with a base. It can be easily produced by neutralizing with.

(I[) (I[[) (wherein, io represents an alkali metal, and R,, R, are the same as above) In the phosphoric acid ester represented by formula (I), the number of carbon atoms represented by R2 is 4 to 4. Examples of the alkyl group 12 include alkyl groups such as butyl, hexyl, octyl, decyl, and dodecyl groups.

In the above reaction formula, the monoalkyl phosphate represented by the formula (II) is produced by reacting a phosphorylating agent such as phosphorus pentoxide, phosphorus oxychloride, or polyphosphoric acid with an organic hydroxy compound having a corresponding alkyl group. After phosphoric acid is obtained, it can be neutralized, and it may be obtained by any of these methods.

In the above reaction, glycidyl methacrylate or glycidyl acrylate represented by formula (III) is
It is preferable to react 1 to 10 moles, particularly 3 to 5 moles, per mole of the monoalkali metal salt of monoalkyl phosphoric acid represented by n).

The solvent used in the reaction is preferably an inert polar solvent, such as water, methyl alcohol, ethyl alcohol, etc., with water being particularly preferred.

The reaction temperature is preferably 30 to 100°C, particularly 50 to 90°C.

Furthermore, polymerization inhibitors or polymerization inhibitors may be added during the reaction, such as hydroquinone monomethyl ether, hydroquinone, 2゜2'-methylenebis(4-
ethyl-6-t-butylphenol) etc. to glycidyl methacrylate or glycidyl acrylate.
~io, oo.

It is preferable to add ppm.

The reaction solution thus obtained contains, in addition to the target compound phosphoric ester, the unreacted compound represented by formula (II[) or its hydrolyzate. Depending on the purpose of use, it is possible to use the reaction product obtained from this reaction solution as it is, but it is also possible to further refine this product to obtain a highly pure product. For example, dodecyl 2-
Sodium hydroxy-3-methacryloyloxypropyl phosphate [R+=CH3, R in the compound of formula (I)
z=C+ zllzs, M=Na, hereinafter, compound (V
), after reacting glycidyl methacrylate with an aqueous solution of sodium dodecyl phosphate, the water is distilled off, or the reaction solution is saturated with an electrolyte such as sodium chloride or potassium chloride, and the organic matter is removed with ethyl ether. After extraction with an organic solvent such as, ethyl ether is distilled off,
After separation from water and extraction and separation of unreacted glycidyl methacrylate with a nonpolar solvent such as n-hexane, acetone is further added to produce dodecyl 2-hydroxy-
By precipitating sodium 3-methacryloyloxyprobyl phosphate and separating it from the hydrolyzate of glycidyl methacrylate soluble in acetone, the target product with good purity can be obtained. In addition, if unreacted glycidyl methacrylate is completely hydrolyzed after the reaction is completed,
The subsequent purification process becomes easier.

Acid form of dodecyl 2-hydroxy-3-methacryloyloxypropyl phosphate [R,= in the compound of formula (I)
CH3, Ih=C+2Hzs, gate=11) can be obtained by making the aqueous solution of Na salt obtained above acidic with an acid, such as hydrochloric acid, and extracting with a solvent such as ethyl ether.

The feature of the present invention is that the compound thus obtained is -1
It has been adopted as a dispersant for suspension polymerization.

In the above formula (I), if the number of carbon atoms in the alkyl group represented by R2 is less than 4, the suspension stability will be insufficient, resulting in the generation of aggregated polymers, which is not preferable. is larger than 12, the compound represented by formula (I) will not exhibit water solubility, which is not preferable.

The reactive dispersant for suspension polymerization of the present invention is preferably used in an amount ranging from 0.2 to 20% by weight, particularly from 1.0 to 10% by weight, based on the water-soluble ethylenically unsaturated monomer. weight%
Preferably, an amount in the range of .

Various types of water-soluble ethylenically unsaturated monomers can be mentioned as the water-soluble ethylenically unsaturated monomers that can be polymerized by suspension polymerization (reverse phase) to which the dispersant of the present invention is applied.

For example, alkali metal salts, ammonium salts, amine salts, acrylamide or methacrylamide or water-soluble N-substituted acrylamide or methacrylamide of acrylic acid or methacrylic acid, vinylimidazole, vinylpyridine, vinylpyrrolidone or sulfonated styrene, vinylsulfonic acid. Alkali metal salts, etc. These monomers can be used in any combination of one or more types. Further, other water-soluble monomers can be copolymerized within a range that does not impair hydrophilicity.

Furthermore, if necessary, a water-soluble crosslinking agent having two or more polymerizable unsaturated groups, such as methylene bisacrylamide, or two or more polymerizable unsaturated groups capable of reacting with the functional group of the ethylenically unsaturated monomer may be added. It is also possible to carry out a crosslinking reaction during or after the (co)polymerization of the monomers using a water-soluble crosslinking agent having a functional group, such as ethylene glycol diglycidyl ether.

The monomer concentration of the monomer aqueous solution when using the 110 reactive dispersant for suspension polymerization of the present invention can be varied within a wide range, but is generally 15 to 80% by weight. Preferably.

When using the dispersant for reverse-phase suspension polymerization of the present invention, as a solvent for reverse-phase suspension polymerization, in principle, all solvents that are inactive for polymerization and do not dissolve water can be used.

Considering the removal of polymerization heat and the drying process of the obtained polymer, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, or a mixed solution thereof having a boiling point of 30 to 200°C are preferred, and n-hexane is particularly preferred. , cyclohexane, benzene, toluene, or a mixed solvent thereof are preferably used.

Furthermore, the ratio between the aqueous monomer solution and the amount of the polymerization-inactive and hydrophobic solvent can be varied over a wide range, but the volume ratio is usually in the range of 1:1 to 1:4. suitable.

For monomer polymerization, a water-soluble radical polymerization initiator,
For example, peroxides, hydroperoxides, or azo compounds are used in known amounts. These polymerization initiators can be used in combination of two or more types, and furthermore, chromium ions, sulfites, hydroxylamine,
It is also possible to add hydrazine or the like and use it as a redox polymerization initiator.

[For production]

The W10 reactive dispersant for suspension polymerization of the present invention not only has the ability as a dispersant, but also has an ethylenically unsaturated bond group in the molecule, so it functions as a dispersant and has water-soluble properties. Can be copolymerized with ethylenically unsaturated monomers. Therefore, when the polymerization of the water-soluble ethylenically unsaturated monomer is completed, the dispersant is incorporated as a constituent into the polymer. For this reason, there is no problem that the dispersant remains or accumulates in the solvent after polymerization, unlike when conventional dispersants are used.

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples and Comparative Examples, but the present invention is not limited only to these Examples.

The compounds used in the following examples are as follows.

n OH0NA CI! 3 0 0 0 HONa Example 1 Cyclohexane 2 was added to a 500 m 14 day round bottom flask equipped with a stirrer, reflux condenser, dropping funnel and nitrogen gas inlet tube.
50 ml of the flask was charged, nitrogen gas was blown in to drive out dissolved oxygen, and the temperature was raised to 75°C.

Separately, in a flask, 30 g of acrylic acid was added to 40 g of ion-exchanged water with 13.4 g of 98% caustic soda while cooling from the outside.
It was neutralized with a solution of g. Next, 0.1 g of potassium persulfate and 0.8 g of Compound A were added and dissolved, and then nitrogen gas was blown into the solution to remove oxygen present in the aqueous solution.

This solution was added dropwise to the above-mentioned 4-hole flask over 30 minutes to polymerize. After the polymerization was completed, the reaction was continued for an additional hour while maintaining the temperature at 75°C. Thereafter, the solvent cyclohexane was distilled off under reduced pressure, and the remaining polymer portion was dried under reduced pressure at 80 to 100°C to obtain a small granular polymer of sodium polyacrylate with a center particle size of 100 to 350. .

The amount of deposits in the tank was 0.1 g.

Example 2 Compound B instead of Compound A 1. Polymerization was carried out according to Example 1 except that Og was used, and a small granular polymer was obtained. The amount of deposits in the tank was 0.2 g.

Example 3 Compound c instead of compound A 1. Polymerization was carried out according to Example 1 except that Og was used, and a small granular polymer containing no aggregates was obtained.

The amount of deposits in the tank was 0.3 g.

Example 4 The same procedure as in Example 2 was carried out. However, when 25 g of sodium vinyl sulfonate was used instead of sodium acrylate as the ethylenically unsaturated monomer aqueous solution, and a monomer aqueous solution prepared by dissolving this in 75 g of ion-exchanged water was used, small granules of sodium polyvinyl sulfonate were obtained. A polymer was obtained. The amount of deposits in the tank was 0.3 g.

Example 5 Polymerization was carried out according to Example 1 except that 1.0 g of Compound D was used instead of Compound A. However, as a monomer, dimethylaminoethyl methacrylate 20% by weight aqueous solution 85
g, 2,2°-azobis(2,4-dimethylvaleronitrile) (trade name V-65, Wako Pure Chemical Industries, Ltd.) as a polymerization initiator
When polymerization was carried out using 0.15 g of the polymer (manufactured by Mimaki Co., Ltd.), a small granular polymer containing no aggregates and having a center particle diameter of 200 to 350 μm was obtained. The amount of deposits in the reaction tank was 0.4 g.

Comparative Example 1 Polymerization was carried out according to Example 1. However, when 1.2 g of compound E was used instead of compound A as a dispersant,
The polymerization system gelled, and a stable particulate polymer could not be obtained.

Comparative Example 2 Polymerization was carried out according to Example 1. However, when 1.2 g of sorbitan monostearate was used as a dispersant, small granular polymers were obtained. The amount of deposits in the reaction tank is 1.0g.
Met.

Comparative Example 3 Polymerization was carried out according to Example 1. However, when Compound F was used instead of Compound A, Compound F did not dissolve in the sodium acrylate aqueous solution. When this system was directly polymerized, the polymerized system turned into a gel.

〔Effect of the invention〕

The 170 reactive dispersant for suspension polymerization of the present invention has the original function of a dispersant and works to maintain the suspension polymerization system stably, but it contains ethylenically unsaturated molecules in the molecule. Because it has a bond, it has the characteristic that it can be copolymerized with a water-soluble ethylenically unsaturated monomer. Therefore, when polymerization is carried out using the -10 reactive dispersant for suspension polymerization of the present invention, the dispersant does not remain in the solvent after the polymerization is completed, so the used solvent does not interfere with the next polymerization. The productivity of the desired polymer can be greatly improved.

In addition, when the 110 reactive dispersant for suspension polymerization of the present invention is used, the amount of aggregates adhering to the inside of the polymerization tank can be suppressed to an extremely small amount, so the polymerization equipment can be used continuously. can do.

Claims (1)

[Claims] 1. General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1 is H or CH_3, R_2 is carbon number 4
to 12 alkyl groups, M represents H, an alkali metal, or ammonium.