JPH0660212B2 - Polymerization method of vinyl monomer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improved method for polymerizing vinyl monomers, and more specifically, suspension of vinyl monomers using an aqueous medium. The present invention relates to a polymerization method for preventing adhesion of polymer scale generated on the inner surface of a polymerization reactor during polymerization or emulsion polymerization.

[Conventional technology]

When polymerizing a vinyl monomer in the presence of a dispersant or emulsifier and a polymerization initiator, a problem that a solid polymer called scale adheres to the inner surface of the polymerization reactor, that is, its inner wall, stirring blades, baffle plates, condensers, etc. There is.

Due to this scale, heat transfer efficiency is reduced, product yield is reduced, quality is deteriorated due to inclusion of peeling scale into products, productivity is reduced due to the time and labor required for scale removal, and occupational health and safety. The above problems cause many disadvantages.

To solve these problems, many methods have been proposed to prevent scale formation and its adhesion to the polymerizer.

For example, dyes, pigments, other polar organic compounds, inorganic acids and their salts, polyvalent metal salts, etc. may be applied to the inner surface of the polymerization vessel or added to an aqueous medium. There are drawbacks such as difficulty in sustaining effects and deterioration of various properties of products. As a method for improving these, a method of applying a polymer compound having a functional group that prevents scale formation to the inner surface of the polymerization vessel has been proposed.

Conventionally, phenolic compounds have been used as polymerization inhibitors, and many methods utilizing them have been proposed.

For example, JP-A-55-16004 discloses a reaction product of a phenol-aldehyde initial condensation product with nitrophenols, and US Pat. No. 4,080,173 discloses self-condensed polyphenols and polyhydric compounds. Naphthol, a condensate of a phenolic compound and an aromatic aldehyde in JP-A-55-54317, JP-A-55-102610.
In the publication, propylene glycol alginate,
Japanese Patent Application Laid-Open No. 55-11209 discloses a nitrile-containing polymer, and Japanese Patent Application Laid-Open No. 58-204006 discloses a reaction product of a drying oil or a semi-drying oil with a phenol compound and optionally an aldehyde on the inner surface of the polymerization vessel. A method of applying is disclosed.

However, when these methods are used, there are many points to be improved, for example, the polymerization rate is lowered, and the durability of the coating film is insufficient, which causes a problem in the sustainability of the descaling effect.

[Problems to be solved by the invention]

As a result of intensive research to eliminate these drawbacks, the present inventors have found that a certain polymer compound, particularly during the polymerization of vinyl monomers, is applied to the inner surface of the polymerization vessel to carry out the polymerization. The inventors have completed the present invention by discovering that scale adhesion can be remarkably prevented and that adhesion to metal is extremely excellent.

[Means for solving problems]

That is, the present invention, when polymerizing a vinyl-based monomer in an aqueous medium, a reaction product of a hydrocarbon resin, a phenolic compound, and an aldehyde compound as desired, by applying to the inner surface of the polymerization vessel in advance. The present invention relates to a method for polymerizing a vinyl-based monomer that prevents scale adhesion on the inner surface of a polymerization device.

As a method for synthesizing a reaction product of a hydrocarbon resin, a phenolic compound and, if desired, an aldehyde compound used in the present invention, (1) a method of simultaneously reacting a hydrocarbon resin, a phenolic compound and an aldehyde compound, (2)
A typical method is to react a hydrocarbon resin with a phenolic compound and then to react this with an aldehyde compound, and (3) a method to react a phenolic compound with an aldehyde compound and then react with a hydrocarbon resin.

In the above method (1), the reaction is carried out according to a usual method for producing a phenol resin except that a hydrocarbon resin is coexistent.

In the case of the method (2), first, the hydrocarbon resin and the phenolic compound are mixed with an acid catalyst in a nitrogen atmosphere at 50
To 250 ° C, preferably 100 to 180 ° C, 5 minutes to 10
The modified phenol compound is produced by reacting for a time, preferably 1 to 5 hours. Then, the modified phenol compound is mixed with an aldehyde and then synthesized according to a usual method for producing a phenol resin.

Examples of the acid catalyst used here include metal halides such as fluorides or chlorides of aluminum, boron, iron, zinc, titanium, etc., or complex compounds thereof, and inorganic such as hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, etc. Examples are acids and organic acids.

Further, in the case of the method (3), a phenolic compound and an aldehyde compound are reacted in advance by a conventional method, and then a hydrocarbon resin is added and heated to obtain a modified phenol resin.

In this case, the reaction temperature is 50 to 140 ° C. and the reaction time is 1
~ 5 hours are preferably used.

The ratio of the hydrocarbon resin and the phenolic compound used in the production of the phenolic polymer compound in the present invention is
Usually, 5 to 200 parts, preferably 5 to 60 parts of the hydrocarbon resin is applied to 100 parts of the phenolic compound.

The ratio of the phenolic compound to the aldehyde compound is 0.1 to 1.5 mol, preferably 0.5 to 1.1 mol, of the aldehyde compound with respect to 1 mol of the phenolic compound.

If the usage ratio is out of this range, the effect of preventing scale adhesion is significantly reduced.

The hydrocarbon resin used in the present invention contains a C ₉ fraction or an α, β unsaturated carboxylic acid, if necessary, added to a C ₅ fraction, and a Friedel-Crafts catalyst at a temperature of 10 to 80 ° C.
It can be obtained by polymerizing for 10 minutes.

Further, the resin obtained in this manner may be further modified with a carboxylic acid or a hydroxyl group to be used in the present invention.

C ₅ cut refers to a boiling point range of 30 obtained in the thermal decomposition of petroleum.
It is a fraction containing olefins and diolefins such as isoprene, piperylene, pentene and methylbutene as main components at -80 ° C.

C ₉ cut refers to the boiling point range of 14 obtained during the thermal decomposition of petroleum.
It is a fraction containing unsaturated hydrocarbons such as styrene, methylstyrene, and indene at 0 to 280 ° C. Examples of the α, β unsaturated carboxylic acid include maleic anhydride and its derivatives. Many of these hydrocarbon resins are commercially available.

The hydrocarbon resin used in the present invention has a molecular weight of 300 to 1
50,000, preferably 500-1,000 with a bromine number of 2
0-300 g / 100 g, preferably 50-200 g / 1
There are no other quality restrictions with 00 g of resin.

The phenolic compound used in the present invention may be any of those commonly used as raw materials for phenol resins, such as phenol, cresol,
monovalent phenol compounds such as p-chlorophenol and xylenol, divalent phenol compounds such as resorcin, hydroquinone, catechol and bisphenol A,
Examples include trivalent phenol compounds such as pyrogallol and hydroxyhydroquinone.

Further, the aldehyde compound may be one that is usually used, and examples thereof include formaldehyde, paraformaldehyde, acetaldehyde and the like.

The descaling agent thus produced is used by dissolving it in a hydrocarbon-based polar solvent. This solution was used as a descaling agent per square meter on the surface of the target polymerization vessel at 0.0
Spraying such that the ratio of ^{1g / m 2 ~10g / m 2} ,
It is used by being attached to the surface of the polymerization vessel by a method such as a rinse method.

The polymerization of the vinyl monomer used in the present invention includes suspension polymerization,
Emulsion polymerization is adopted, but the dispersant, emulsifier, initiator and the like used in this polymerization are not particularly limited and commonly used ones can be used.

For example, as a dispersant or an emulsifier, a partially saponified product of polyvinyl acetate, an acrylic acid copolymer, a cellulose derivative, gelatin, a protective colloidal compound such as starch, or an ester of a higher fatty acid and a polyhydric alcohol,
Nonionic surfactants such as polyoxyethylene derivatives,
Anionic surfactants such as metal salts of higher fatty acids and metal salts of alkylbenzene sulfonic acids are used.

As the polymerization initiator, organic peroxides such as benzoyl peroxide, lauroyl peroxide, dioctyl peroxydicarbonate, azo compounds such as azobisisodimethylvaleronitrile, and persulfates such as potassium persulfate and ammonium persulfate are used. To be done. The vinyl-based monomer referred to here is a monomer having a vinyl group, for example, olefins such as ethylene and propylene, vinyl halides such as vinyl chloride and vinylidene chloride, vinyl esters such as vinyl acetate, Vinyl ethers such as ethyl vinyl ether, acrylic acid esters such as methyl methacrylate, metal salts or esters such as maleic acid and fumaric acid, aromatic vinyls such as styrene, and diene-based monoamines such as butadiene, chloroprene and isoprene And vinyl monomers that are copolymerizable with these monomers. The polymerization temperature is usually in the range of 30 to 80 ° C.

INDUSTRIAL APPLICABILITY The present invention can be used for the polymerization of the above vinyl-based monomers alone or a mixture of two or more vinyl-based monomers, and particularly shows a remarkable effect on the polymerization of vinyl chloride-based monomers. .

〔The invention's effect〕

The method described above can significantly improve the scale adhesion.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples.
This does not limit the scope of the invention.

[Reference Example 1] A four-necked flask equipped with a stirrer, a thermometer and a reflux condenser had a molecular weight of 900 and a bromine number of 60 (g / 100).
g), softening point 60 ° C. hydrocarbon resins (C ₅ petroleum resins commercially available) 100 parts, 100 parts of pyrogallol, p- toluenesulfonic acid 1 part were charged, 4 hours under a nitrogen atmosphere at a reaction temperature 0.99 ° C. The reaction I went.

After the reaction was completed, the reaction product was cooled to 100 ° C. or lower, and then 600 parts of water was added to dehydrate and wash, followed by drying to obtain a reaction product.

Reference Example 2 As in Reference Example 1, pyrogallol 100 was placed in a four-necked flask equipped with a stirrer, a thermometer and a reflux condenser.
Part, 50 parts of the participating hydrogen resin used in Reference Example 1 and 1 part of aluminum chloride were charged, reacted for 1 hour under a nitrogen atmosphere and then cooled, 75 parts of 35% formaldehyde was added, and the mixture was refluxed for 1 hour. The reaction was carried out. Then, 600 parts of water was added, and the mixture was dehydrated and washed, and then dried to obtain a reaction product.

Reference Example 3 As in Reference Example 1, pyrogallol 100 was placed in a four-necked flask equipped with a stirrer, a thermometer and a reflux condenser.
Parts, 68 parts of 35% concentrated formaldehyde and 2000 parts of 50% phosphoric acid were reacted at 60 ° C. for 1 hour to obtain a reddish purple precipitate.

A product was obtained by reacting 100 parts of the precipitate obtained by dehydrating and drying this with 50 parts of the hydrocarbon resin used in Reference Example 1 in the same manner as in Reference Example 1.

Reference Example 4 As in Reference Example 1, pyrogallol 100 was placed in a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser.
Parts, 75 parts of 35% formaldehyde, 50 parts of the hydrocarbon resin used in Reference Example 1, and 2 parts of oxalic acid dihydrate were charged and reacted under a nitrogen atmosphere for 4 hours.

The reaction temperature was controlled by refluxing the water in the system.

After the reaction was completed, 400 parts of water was added, and after dehydration and washing, it was dried to obtain a reaction product.

[Reference Example 5] A reaction product was obtained in the same manner as in Reference Example 1, except that hydroxyhydroquinone was used instead of pyrogallol.

Comparative Example 1 After charging 250 parts of pure water, 0.25 part of partially saponified polyvinyl acetate and 0.05 part of 2,2′-azobis-2,4 dimethylvaleronitrile into a polymerization vessel having an internal volume of 1 m ³ . Then, 100 parts of vinyl chloride monomer was injected under reduced pressure.

Then, the mixture was heated to 57 ° C. with stirring, and when the pressure in the polymerization reactor fell below 2 kg / cm ² from the pressure in the steady state of the polymerization reaction, the recovery of unreacted monomers was started.

The polymerization time at this time was 10 hours.

Then, after recovering the unreacted monomer, the polymerization suspension was taken out from the polymerization vessel, and the inner surface was washed with low pressure water. Then, when the amount of scale attached to the inner surface of the polymerization vessel was measured, the results shown in Table 1 were obtained.

[Comparative column 2] An aqueous solution containing 126 parts of pyrogallol and 85 parts of formaldehyde having a concentration of 35% was used as a 50 wt% aqueous solution of phosphoric acid 200
In addition to 0 parts, a water-insoluble solid was obtained which was reacted at 60 ° C. for 1 hour. This solid was washed with water, dried, and made into a 3% acetone solution, spray-coated on the inner surface of the polymerization vessel used in Comparative Example 1, and dried.

The coating amount at this time was 0.4 g / m ² .

When a polymerization reaction was carried out in the same manner as in Comparative Example 1 using this polymerization vessel, the polymerization time was 10 hours, and the amount of scale attached was as shown in Table 1.

[Examples 1 to 5] The products obtained by the methods of Reference Examples 1 to 5 were each made into a 3% acetone solution and spray-coated on the inner surface of the polymerization vessel used in Comparative Example 1 and dried. The coating amount at this time was 0.4 g / m ² .

When a polymerization reaction was carried out in the same manner as in Comparative Example 1 using this polymerization vessel, the polymerization time was 10 hours each, and the amount of scale adhesion was the result shown in Table 1.

Comparative Example 3 250 parts of pure water and 5 parts of vinyl acetate were placed in a polymerization vessel having an internal volume of 1 m ^3.
Parts, partially saponified polyvinyl acetate 0.25 parts, 2,2'-
After charging 0.05 parts of azobis-2,4 dimethylvaleronitrile, 100 parts of vinyl chloride monomer was injected under reduced pressure, and then heated to 60 ° C. with stirring, and the pressure in the polymerization reactor was set to the polymerization reaction. 2kg / cm ³ from the pressure in the steady state of
When the temperature dropped, collection of unreacted monomer was started.

The polymerization time at this time was 8.5 hours.

Then, after recovering the unreacted monomer, the polymerization suspension was taken out from the polymerization vessel, and the inner surface was washed with water.

After that, when the amount of scale attached to the inner surface of the polymerization vessel was measured, the results shown in Table 2 were obtained.

[Comparative Example 4] The solid obtained by the method of Comparative Example 2 was used as a 3% acetone solution, and was spray-coated on the inner surface of the polymerization vessel used in Comparative Example 3 and dried.

The coating amount at this time was 0.5 g / m ² .

When a polymerization reaction was carried out in the same manner as in Comparative Example 3 using this polymerization vessel, the polymerization time was 8.5 hours, and the amount of scale adhesion was as shown in Table 2.

[Examples 6 to 10] The products obtained by the methods of Reference Examples 1 to 5 were each made into a 3% acetone solution, and spray-coated on the inner surface of the polymerization vessel used in Comparative Example 3 and dried. The coating amount at this time was 0.5 g / m ² .

When a polymerization reaction was carried out in the same manner as in Comparative Example 3 using this polymerization vessel, the polymerization times were both 8.5 hours, and the amounts of scale adhesion were as shown in Table 2.

Comparative Example 5 100 parts of pure water and 1 part of chloroprene were placed in a polymerization vessel having an internal volume of 1 m ^3.
After charging 00 parts, polyoxystyrene beef tallow alkyl propylene diamine 4 parts, acetic acid 1 part, alumina sol 0.5 part, and sodium formaldehyde sulfoxylate 0.02 part, t-butyl hydroperoxide 0.01 part at 40 ° C. Was added in 10 hours to complete the polymerization.

After the polymerization was completed, the amount of scale attached to the inner surface of the polymerization vessel was measured, and the results shown in Table 3 were obtained.

Comparative Example 6 The solid obtained by the method of Comparative Example 2 was used as a 3% acetone solution and spray-coated on the inner surface of the polymerization vessel used in Comparative Example 5 and dried.

The coating amount at this time was 0.3 g / m ² .

When a polymerization reaction was carried out in the same manner as in Comparative Example 5 using this polymerization vessel, the amount of scale attached was as shown in Table 3.

[Examples 11 to 15] The products obtained by the methods of Reference Examples 1 to 5 were each made into a 3% acetone solution, and spray-coated on the inner surface of the polymerization vessel used in Comparative Example 5 and dried. The coating amount at this time was 0.3 g / m ² .

Polymerization reactions were carried out in the same manner as in Comparative Example 5 using this polymerization vessel, and the results of the amount of scale adhesion shown in Table 3 were obtained.

As described above, in any of the examples, the number of effective batches was improved by remarkably reducing the amount of scale deposit and improving the durability of the coating film as compared with the comparative example.

* 1 The number of effective batches in the table means that the applied scale adhesion preventive agent will lose its scale adhesion prevention effect due to peeling due to slurry stirring due to polymerization, and it will adversely affect the quality such as foreign matter and hue. It means the number of batches that can be effectively used until polymerization cannot be continued without a washing operation.

Claims (3)

[Claims] 1. When polymerizing a vinyl-based monomer in an aqueous medium, a reaction product of a hydrocarbon resin, a phenolic compound and, if desired, an aldehyde compound is applied to the inner surface of the polymerization vessel in advance. A method for polymerizing vinyl monomers. 2. The vinyl monomer is vinyl chloride alone, or
The polymerization method according to claim 1, which is a mixture of vinyl chloride and a monomer copolymerizable therewith. 3. The polymerization method according to claim 1, wherein the phenolic compound is pyrogallol or hydroxydroquinone.