JP2702232B2 - Inhibitor of vinyl polymer scale and method of preventing vinyl polymer scale using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polymer scale inhibitor generated when a vinyl monomer is polymerized, and a method for preventing a polymer scale using the same. More specifically, the present invention relates to a polymer scale inhibitor applicable to a suspension polymerization method, an emulsion polymerization method, and a bulk polymerization method and applicable to continuous batch polymerization, and a method for preventing a polymer scale using the same.

[Problems to be Solved by the Related Art] During the polymerization of vinyl monomers, the polymer adheres to the inner wall surface, baffles, stirring blades, etc. of the polymerization reactor (hereinafter, also referred to as the inner wall surface). Scale is produced, which reduces the effect of removing the heat generated during the polymerization or mixes into the product to deteriorate the product quality. Furthermore, it is well known that scale removal requires a great deal of expense and production disadvantages such as the inability to carry out polymerization continuously.
In addition, to increase productivity by increasing the efficiency of heat removal and increasing the size of the polymerization reactor, there is a tendency to use a polymerization reactor made of stainless steel, clad copper, or nickel, rather than a glass-lined polymerization reactor. .

However, polymerization reactors made of stainless steel, clad steel, and nickel are more likely to generate scale and are more difficult to remove than glass-lined polymerization reactors. It is well known in the art that it has the disadvantage of increasing costs.

Conventionally, a scale prevention method has been energetically studied, particularly in a suspension polymerization method of vinyl chloride or a monomer containing vinyl chloride, and some results have been obtained. For example, a condensate of an aldehyde and a phenolic compound, a condensate of an aromatic amine, a condensate of an aromatic amine and a nitro compound or a sulfonated product thereof is applied to the inner wall surface of a polymerization reactor to prevent scale. Methods are known.

However, it is difficult to say that a sufficient effect is obtained by these methods. Further, in these methods, the suspension polymerization method in which a highly water-soluble vinyl monomer, for example, vinyl acetate and vinyl chloride is copolymerized, has a problem that the scale prevention effect is reduced. Further, there is a problem that the emulsion polymerization of vinyl chloride hardly provides a scale prevention effect.

Except for the production of vinyl chloride resins, NBS resins, ABS resins, and polymethacrylates are generally employed in the production of emulsion-processable resins by emulsion polymerization. Then, almost no scale prevention effect can be obtained.

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to develop a polymer scale inhibitor and a method for preventing the polymer scale which have improved the conventional disadvantages. In the polymerization of the product, a polymerization reaction vessel is previously prepared using a mixture of a reduction reaction product obtained by reducing a reaction product of an aminonaphthalene compound and a naphthoquinone compound, and colloidal alumina, titanium oxide and / or tin oxide. The present inventors have found that coating the inside can effectively prevent the polymer scale, and have completed the present invention.

[Example] The polymer scale inhibitor of the present invention is a reaction product obtained by reducing a reaction product of an aminonaphthalene compound and a naphthoquinone compound (hereinafter, referred to as a reduction reaction product).
And a mixture of colloidal alumina, colloidal titanium oxide and / or colloidal tin oxide.

The reduction reaction product is a component that firmly adheres to the inner wall surface or the like of the polymerization reactor and has a function of holding the colloid particles firmly while exhibiting a scale prevention effect by itself,
An aminonaphthalene compound and a naphthoquinone compound are dissolved in a synthetic solvent, reacted at a predetermined temperature after addition of a catalyst for a predetermined time, and the resulting reaction product is reduced and then obtained by excessive fractionation. It is about 40,000.

The aminonaphthalene compound used for producing the reduction reaction product is not particularly limited, and any known aminonaphthalene compound can be used. Specific examples thereof include, for example, monoaminonaphthalene such as 1-aminonaphthalene and 2-aminonaphthalene, 1,2-diaminonaphthalene, 1,4-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene, And polyaminonaphthalenes such as 2,6-diaminonaphthalene and 2,7-diaminonaphthalene. Further, a substituent such as a sulfonic acid group, a carboxylic acid group, or a halogen atom may be present on the naphthalene ring present in the aminonaphthalene compound. Among these aminonaphthalene compounds, polyaminonaphthalene is preferred because it has a good scale prevention effect.

The naphthoquinone compound used for producing the reduction reaction product is not particularly limited, and any known naphthoquinone compound can be used. As a specific example,
For example, carbonyl groups such as 1-naphthoquinone and 2-naphthoquinone have one naphthoquinone (hereinafter referred to as mononaphthoquinone), 1,2-naphthoquinone, 1,3-naphthoquinone, 1,4-naphthoquinone, 1,8-naphthoquinone, and 2 Carbonyl groups such as 2,3-naphthoquinone and 2,6-naphthoquinone having two naphthoquinones (hereinafter referred to as polynaphthoquinone)
And so on. Further, the naphthalene ring present in the naphthoquinone compound may have a substituent such as a sulfonic acid group, a carboxylic acid group and a halogen atom. Among these naphthoquinone compounds, polynaphthoquinone is preferred from the viewpoint that the effect of preventing scale is improved.

The molar ratio of the aminonaphthalene compound to the naphthoquinone compound is preferably about 1/5 to 5/1. When the ratio of the aminonaphthalene compound is less than 1/5, the reaction hardly occurs, and when the ratio is more than 5/1, the scale preventing effect tends to decrease.

As described above, when the aminonaphthalene compound is reacted with the naphthoquinone compound, a catalyst, a synthesis solvent, and the like are used.

Specific examples of the synthesis solvent include known alcohols, ketones, esters, ethers, and water. These may be used alone or in combination of two or more. The use amount thereof is preferably about 2 to 200 times by weight with respect to the total amount of the aminonaphthalene compound and the naphthoquinone compound from the viewpoint of uniformly reacting.

Specific examples of the catalyst include acidic catalysts such as ferric chloride, ferric sulfate, cupric chloride, cupric sulfate, hydrochloric acid, and phosphoric acid. As the amount of the catalyst used,
The amount is preferably about 0.1 to 5 mol per 1 mol of the aminonaphthalene compound.

The reaction temperature is 20 to 80 ° C, and the reaction time is 10 minutes to
About 10 hours are common.

These conditions have no critical meaning and vary depending on the catalyst used. If ferric chloride, ferric sulfate, cupric chloride and cupric sulfate are preferably used, the desired average molecular weight is obtained by a reaction at room temperature for 1 to 5 hours.
About 1000 to 40000 reaction products are obtained.

The reaction product of the aminonaphthalene compound and the naphthoquinone compound thus obtained is reduced, and a reduction reaction product is obtained.

The reduction method is not particularly limited, and any known method can be employed. At the time of reduction, for example, a reducing agent may be added to the reaction product and the synthesis solvent for reduction,
The reaction product may be excessively separated from the synthesis solvent and treated with a reducing agent, or the excessively separated reaction product may be dissolved again in the solvent and subjected to a reduction treatment.

The reducing agent is not particularly limited, and any known one can be used. Specific examples thereof include known ones such as sodium hydrogen sulfite, sodium thiosulfate, aluminum lithium hydride, and hydrogen.

The amount of the reducing agent used is preferably an amount that is about 1 to 5 times the number of moles of naphthoquinone used in the reaction, and the reduction conditions may be any known methods.

Examples of the reduction reaction product thus obtained include, for example, a reduction reaction product of a reaction product of 1-aminonaphthalene and 1-naphthoquinone, and a reduction reaction product of a reaction product of 2-aminonaphthalene and 2-naphthoquinone. Thing, 1,
A reduction reaction product of a reaction product of 4-diaminonaphthalene and 2,3-naphthoquinone, 1,8-diaminonaphthalene and 1,2-
Examples include a reduction reaction product of a reaction product of naphthoquinone and a reduction reaction product of a reaction product of 1,8-diaminonaphthalene and 2,3-naphthoquinone.

When the reduction reaction product uses polyaminonaphthalene as the aminonaphthalene compound and polynaphthoquinone as the naphthoquinone compound, the scale prevention effect is particularly good. Although the cause is not clear, the degree of condensation of the reaction product is increased, the adhesion to the inner wall surface is improved, the dissolution and elution resistance in the polymerization reaction medium is improved, and the hydroxyl group-containing compound has a polymerization inhibiting effect. It is considered that the amount is large.

The alumina colloid, titanium oxide colloid, and / or tin oxide colloid (hereinafter, also referred to as colloids) used in the present invention are substances such as aluminum oxide, titanium oxide, and tin oxide, and are used to impart hydrophilicity. Component. The smaller the particle size of the colloids is, the better the specific surface area is, but the smaller the particle size, the more difficult it is to manufacture and the harder to obtain. Therefore, the particle diameter of the colloid is preferably 200 μm or less,
μ or less is more preferable, and usually about 20 μm or more. In addition, when the particle diameter of the colloids increases, the scale prevention effect decreases.

Among the colloids, use of a titanium oxide colloid or an alumina colloid provides a particularly large scale preventing effect.

Since such colloids are generally marketed as aqueous dispersions or liquids with improved dispersibility in organic solvents,
It can be mixed with the reduction reaction product as it is. The colloids may be used alone or in combination of two or more.

The colloid alone has no scale preventing effect at all, but exhibits a remarkable scale preventing effect when used in combination with the reduction reaction product. Although the mechanism is not clear, these colloids are hydrophilic and do not dissolve or elute in the polymerization reaction medium such as water or vinyl monomers. Adsorbs
It is considered that the formation of the water layer prevents the scale-adhering active substance generated in the polymerization medium from adhering to the inner wall surface or the like.

In the present invention, a mixture (hereinafter, also referred to as a coating liquid) for coating the inside of the polymerization reaction apparatus by mixing the reduction reaction product and the colloids is prepared.

The coating solution is prepared by dissolving the reduction reaction product in a solvent (coating solvent) that will be a solvent for the coating solution, and then dispersing the colloids.

When the reduction reaction product is, for example, a liquid containing a coating solvent as a solvent, the colloids may be dispersed therein or the concentration thereof may be adjusted, and then the colloids may be dispersed.

As the coating solvent, dimethylformamide, dimethylacetamide, dimethylsulfoxide, methylpyrrolidone and the like can be used in addition to the above-mentioned synthesis solvent, and these may be used alone or in combination of two or more.

The concentration of the reduction reaction product in the coating liquid is 0.1 to 5
% (Weight%, the same applies hereinafter). The mixing ratio of the reduction reaction product / colloid is preferably about 1 / 0.3 to 1/3 by weight. If the mixing ratio of the reduction reaction product / colloid is out of the above range and is small or large, the scale prevention effect is reduced.

The coating liquid thus prepared is a dispersion of several centipoise to about 20 centipoise.

The coating solution is coated on the inner wall surface of the polymerization reactor which has been washed beforehand, and dried.

The method of coating is not particularly limited, and various methods such as brush coating, spray coating, and coating a polymerization reactor with a coating liquid filled therein can be employed.

The coating amount 0.01~10g the inner wall surface 1 m ² per solids
Degree is preferable, and about 0.1 to 5 g is more preferable. If the coating amount is less than about 0.01 g, the scale preventing effect tends to decrease. If the coating amount exceeds about 10 g, the scale preventing effect is substantially the same, which is economically disadvantageous. Drying is to evaporate the coating solvent, and in practice, it may be dried at about 50 to 120 ° C. under reduced pressure or air blowing for about 10 minutes to 3 hours as necessary.

The polymerization reactor referred to in the present invention is not limited to a polymerization reactor made of stainless steel, clad steel, or a metal such as a nickel alloy, but is also a concept including a polymerization reactor made of glass lining and the like. Necessary components such as baffles and stirring blades are attached to these polymerization reactors.

After applying and drying the coating solution on the inner wall of the polymerization reactor in advance as described above, the aqueous medium, a vinyl monomer, a polymerization initiator, a dispersant, an emulsifier, an additive, and the like are charged and suspended. When polymerization such as polymerization, emulsion polymerization, or bulk polymerization is performed, it is possible to effectively prevent the adhesion of the polymer scale to the inner wall surface or the like of the polymerization reactor, and conventionally, it is very difficult to prevent the polymer scale. Even in the conventional emulsion polymerization method of methacrylic acid ester and acrylic acid ester, and even when the polymerization reaction medium is on the acidic side or on the alkaline side, a remarkable effect of preventing polymer scale is exhibited. In addition, in the bulk polymerization method, after coating and drying the coating liquid, once washed with water,
After forming a water film on the surface of the coating film, it is preferable to carry out polymerization by charging a vinyl monomer, a polymerization initiator and the like.

The above-mentioned suspension polymerization, emulsion polymerization, bulk polymerization and the like are polymerizations by known polymerization methods.

The vinyl monomer means a known vinyl monomer, a vinylidene monomer and a known diene monomer, and specific examples of the vinyl monomer include, for example, vinyl chloride, vinylidene chloride, and acetic acid. Vinyl, styrene, α-methylstyrene, acrylate, methacrylate, acrylic acid, methacrylic acid, phenylmaleimide, ethylene, propylene, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, 1-butene,
Known monomers such as 1-hexene, butadiene, isoprene, chloroprene and the like can be mentioned.

Specific examples of the dispersant and emulsifier include, for example, inorganic compounds such as calcium phosphate and barium sulfate, methyl cellulose, ethyl cellulose, polymer compounds such as partially saponified polyvinyl acetate, polyoxyethylene alkyl ethers, and polyoxyethylene sorbitanate. And anionic surfactants such as alkali metal salts of alkylbenzenesulfonic acid, metal salts of alkylnaphthalenesulfonic acid and metal salts of dialkylsulfosuccinic acid.

Specific examples of the polymerization initiator include, for example, azo compounds, diacyl peroxides, hydroperoxides,
Known polymerization initiators such as diacyl peroxide, dialkyl peroxide, alkyl perester, peroxydicarbonate, persulfate, and redox initiator are exemplified.

Examples of the additive include a known chain transfer agent, a known antioxidant, a known electrolyte compound, a known plasticizer, and the like.

Hereinafter, the present invention will be described in more detail based on examples, but these do not limit the present invention at all.

Production Examples 1 to 10 and Comparative Production Example 1 Aminonaphthalene and naphthoquinone shown in Table 1 were dissolved in a mixed solvent of 300 cc of methanol and 30 cc of tetrahydrofuran, stirred for 1 hour, and then dissolved in 60 cc of water, followed by aqueous ferric chloride. Was added and reacted at room temperature for 3 hours.
After separating the reaction product by filtration, the obtained reaction product was reduced at 30 ° C. for 3 hours in a mixed solvent of 300 cc of methanol and 700 cc of water in which 3 mol of a reducing agent was dissolved. Then, sort out,
The reduction reaction products of Sample Nos. 1 to 11 were obtained. In addition,
Sample No. 1 is a reduction reaction product obtained from a reaction product of aniline and benzoquinone for comparison.

Examples 1 to 3 and Comparative Examples 1 to 5 The reduction reaction product of Sample No. 5 obtained by the above method was prepared by using dimethylformamide / butanol / water (85/10/5).
(Volume ratio)) and adjusted to a concentration of 1%. Then
Alumina colloid, titanium oxide colloid, tin oxide colloid, aluminum sulfate or aluminum chloride are added thereto so that the weight ratio of colloid particles or metal salt to the reduction reaction product becomes 1/1, and the mixture is dispersed to form a coating liquid. Prepared. The coating solution is applied to the inner wall of the polymerization reactor, which has been washed beforehand, with a brush so that the inner surface becomes 1 g (solid content) per 1 m ^{2 and} dried at 70 ° C. for 2 hours.
The polymerization of the following formula 1 was repeated until scale adhesion was observed.

The coating liquid is applied to the inner wall surface of the polymerization reactor and dried, and the presence or absence of hydrophilicity of the formed film and the number of polymerizations (scale prevention continuous batches) that could be performed without observing scale adhesion were determined. It is shown in Table 2.

In Comparative Examples 2 and 3, a reaction product (unreduced product) of 0.1 mol of 1,8-diaminonaphthalene and 0.1 mol of 1,2-naphthoquinone was used instead of the reduction reaction product of Sample No. 5. The case of using is shown.

(Formulation 1: Emulsion polymerization method of vinyl chloride) 8 kg of water in which 80 g of sodium dodecylbenzenesulfonate was dissolved, 4 kg of vinyl chloride and 8 g of potassium persulfate were charged into a coated stainless steel polymerization reactor having an inner volume of 20, and the mixture was heated at 60 ° C for 10 minutes. Polymerization was carried out for hours. The pH of the polymerization medium at the end of the polymerization was 3.5.

(Hydrophilicity) Apply the coating solution to the inner wall of the polymerization reactor, etc.
After drying, the surface was brought into contact with water, and the surface wettability of the water was observed. The state where the water was wet on the entire surface and the state where the water was repelled were judged as no.

Table 2 shows that a remarkable scale-preventing effect can be obtained by using the reduction reaction product in combination with the alumina colloid, the titanium oxide colloid, or the tin oxide colloid. In particular, when titanium oxide colloid or alumina colloid is used, a large scale preventing effect can be obtained.

Examples 4 to 14 and Comparative Examples 6 to 15 The type and particle size of colloidal particles or metal salts, and the weight ratio of (reduction reaction product) / (colloidal particles or metal salts) were changed as shown in Table 3 and polymerization was carried out. Except that the method was changed to the method of the following formulation 2, the presence or absence of hydrophilicity and the number of continuous batches for scale prevention were examined in the same manner as in Examples 1 to 3. The results are shown in Table 3.

(Formulation 2: Emulsion polymerization of butyl acrylate) A coated stainless steel polymerization reactor having an inner volume of 3 was charged with 1500 g of water whose pH was adjusted to 11.5 with sodium carbonate and sodium hydroxide, 800 g of butyl acrylate, and 15 g of sodium oleate. , 10 g of cumene hydroperoxide, 5 g of Rongalit, 0.15 g of sodium ethylenediaminetetraacetate, and 0.07 g of ferrous sulfate, and polymerization was carried out at 50 ° C. for 10 hours.

According to Table 3, the use of the reduction reaction product and the alumina colloid particles can provide a scale prevention effect, but especially when the weight ratio of the reduction reaction product to the colloid particles is in the range of 1 / 0.3 to 1/3. It can be seen that a remarkable scale prevention effect can be obtained. It is also found that titanium oxide colloid and tin oxide colloid particles have a remarkable scale preventing effect when used in combination with the reduction reaction product. In addition, non-hydrophilic zirconium oxide colloids and aluminum chloride, aluminum sulfate, antimony oxide colloid particles that are easily soluble in polymerization media (water, alkali, monomer), sodium silicate, silicate colloid, unreduced reaction products It can be seen that there is no or almost no scale prevention effect when such a method is used. It can also be seen that the smaller the particle size of the coagulated alumina colloid and alumina colloid, the greater the scale prevention effect.

Examples 15 to 27 and Comparative Examples 16 to 23 Examples 1 to 3 except that the colloidal particles or metal salts and the reduction reaction product were changed as shown in Table 4 and the polymerization method was changed to the method of Formula 3 below. The number of continuous batches of hydrophilic organic and anti-scaling was determined as described above. 4th result
It is shown in the table.

(Formulation 3: Methyl methacrylate emulsion polymerization method) 2.5 kg of water and 25 sodium dodecylbenzenesulfonate were placed in a coated stainless steel polymerization reactor having an inner volume of 5
g, 8 g of potassium peroxide, 1.5 kg of methyl methacrylate and 500 g of styrene were charged and polymerized at 70 ° C. for 8 hours.
The pH of the polymerization medium at the end of the polymerization was 3.

Table 4 shows that the use of colloidal alumina, titanium oxide or tin oxide in combination with the reduction reaction product of the reaction product of aminonaphthalene and naphthoquinone provides a remarkable scale prevention effect. Also,
It can also be seen that using polyaminonaphthalene as the aminonaphthalene and polynaphthoquinone as the naphthoquinone provides a more remarkable scale prevention effect.

It is also found that among the colloids, the use of titanium oxide colloid and alumina colloid has a large scale preventing effect.

[Effects of the Invention] The present invention shows a remarkable effect in preventing the polymer scale from adhering to the inner wall surface of the polymerization reactor when polymerizing a vinyl monomer, and the polymerization is continuously performed repeatedly. The effect lasts. The present invention also shows a remarkable scale-preventing effect in emulsion polymerization of acrylates and methacrylates, which has conventionally been difficult to prevent scales.

Claims (8)

(57) [Claims] 1. A vinyl polymer scale comprising a mixture of a reduction reaction product obtained by reducing a reaction product of an aminonaphthalene compound and a naphthoquinone compound, and colloidal alumina, colloidal titanium oxide and / or colloidal tin oxide. Inhibitor. 2. The vinyl polymer scale inhibitor according to claim 1, wherein polyaminonaphthalene is used as the aminonaphthalene compound and polynaphthoquinone is used as the naphthoquinone compound. 3. The vinyl polymer scale inhibitor according to claim 1, wherein a titanium oxide colloid is used as the alumina colloid, the titanium oxide colloid, and / or the tin oxide colloid. 4. The vinyl polymer scale inhibitor according to claim 1, wherein an alumina colloid is used as the alumina colloid, the titanium oxide colloid, and / or the tin oxide colloid. 5. A polymerization reaction of a vinyl monomer, wherein a reduction reaction product obtained by reducing a reaction product of an aminonaphthalene compound and a naphthoquinone compound, an alumina colloid, a titanium oxide colloid and / or a tin oxide colloid A method for preventing the scale of a vinyl polymer, which comprises coating the inside of a polymerization reactor in advance with a mixture of the above. 6. The method according to claim 5, wherein polyaminonaphthalene is used as the aminonaphthalene compound and polynaphthoquinone is used as the naphthoquinone compound. 7. The method according to claim 5, wherein a titanium oxide colloid is used as the alumina colloid, the titanium oxide colloid, and / or the tin oxide colloid. 8. The method for preventing vinyl polymer scale according to claim 5, wherein alumina colloid is used as the alumina colloid, titanium oxide colloid, and / or tin oxide colloid.