JPS63175002A - Production of vinyl polymer - Google Patents

Abstract

PURPOSE:To effectively prevent the deposition of a polymer scale on the inner wall of a polymerizer, etc., by polymerizing a vinyl monomer in a polymerizer having a coating layer produced by applying and drying a coating liquid containing a fluorine-containing surfactant and a silicic acid compound. CONSTITUTION:The inner wall of a polymerizer and the other part of the polymerizer contacting with monomer during the polymerization process, e.g. stirrer, etc., is coated with a scale-preventive liquid containing (A) 100pts.wt. of a fluorine-containing surfactant (e.g. perfluoroalkylsulfonic acid ammonium salt) and (B) usually 1-600pts.wt. of a silicic acid compound (e.g. colloidal silica, orthosilicic acid, water-glass, etc.). The coating liquid is dried and a vinyl polymer is polymerized in the polymerizer having the produced coating layer. The method is effective irrespective of the method of polymerization, material of the polymerizer and the kind of the monomer. Since the scale- preventing agent is colorless, there is no fear of causing contamination of the product.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing vinyl polymers.

[Conventional technology]

Vinyl polymers are produced by suspension polymerization, emulsion polymerization, solution polymerization, gas phase polymerization, or bulk polymerization, but in all of these polymerization methods, the inner wall of the polymerization vessel In addition, there is a problem of polymer scale adhesion to the stirring equipment and other areas. In other words, when vinyl monomers are polymerized using these methods, polymer scale adheres to parts that come into contact with the monomer during polymerization, such as the inner wall of the polymerization vessel and the stirring device, which reduces the yield of the polymer and the polymerization rate. In addition to reducing the cooling capacity of the equipment, this adhered scale flakes off and mixes into the product, reducing the quality of the product.

Furthermore, in order to remove this adhered scale, not only does it require excessive labor and time, but also unreacted monomers are adsorbed in this scale, so removal work is now extremely important. There is also the problem that the monomers in question (acrylonitrile, vinyl chloride, etc.) pose a risk of injury to the human body.

Therefore, as a method to prevent this polymer scale from adhering to the inner walls of the polymerization vessel, for example, coating the inner walls of the polymerization vessel and the stirrer with polar organic compounds such as amine compounds, quinone compounds, aldehyde compounds, dyes, pigments, etc. Method (Japanese Patent Publication No. 45-30343, No. 45-308
35), a method of applying a polar f-organic compound or dye treated with a metal salt (Japanese Patent Publication No. 52-24953)
Publication No. 2), etc. have been proposed.

[Problem that the invention seeks to solve]

However, in the above conventional methods, depending on the type of polymerization method,
Particularly in the case of emulsion polymerization, scale adhesion cannot be sufficiently prevented, and it also depends on the type of additives such as monomers and polymerization catalysts, the composition of the polymerization system, and the material of the polymerization vessel, especially stainless steel. However, there is a problem in that it is not possible to sufficiently prevent the adhesion of polymer scale. In addition, the compounds used as scale inhibitors in the above method are generally colored and may contaminate the product, and some of them are not non-toxic, which poses hygienic problems.

[Means for solving problems]

The present invention solves the above-mentioned problems of the conventional method by adding (a) a fluorine-based surfactant and ) Provides a method for producing a vinyl polymer, which comprises polymerizing a vinyl monomer in a polymerization vessel having a coating film formed by applying and drying a coating solution containing a silicic acid compound. be.

The fluorine-based surfactant that is component (a) of the coating liquid used in the present invention is not particularly limited, and examples include ammonium salts of perfluoroalkylsulfonic acids (Florard FC
-93; manufactured by Sumitomo 3M), potassium salt of perfluoroalkylsulfonic acid (Florad FC-95, FC-
98, FC-129: manufactured by Sumitomo 3M), perfluoroalkyl quaternary ammonium iodide (Florado F
C-135; manufactured by Sumitomo 3M), perfluoroalkyl polyoxyethylene ethanol (Florard FC-1
70C (manufactured by Sumitomo 3M), fluorinated alkyl ester (Flora)' FC-430, FC-431; manufactured by Sumitomo 3M), and these can be used alone.
It can also be used in combinations of more than one species. Particularly preferable fluorosurfactants include Florard FC-129, FC
-135 and FC-170C.

Furthermore, the silicic acid compound that is component (b) of the coating solution is not particularly limited, and includes, for example, colloidal silica, water-soluble silicic acids, or silicate compounds, and specific examples thereof are as follows. be.

Colloidal silica, orthosilicic acid, metasilicic acid, mesotrisilicate, mesotrisilicate, mesotetrasilicic acid, sodium metasilicate, potassium hydrogen disilicate, lithium orthosilicate, lithium orthosilicate, water glass, 12-silicate tungstic acid, Iso-12-silicotungstic acid, 10-silicotungstic acid, potassium 12-silicotungstate, iso-12-potassium silicotungstate, potassium 10-silicotungstate, sodium 12-silicotungstate, iso-12-silicotungstate acid sodium,
These include silicomolybdic acid, potassium silicomolybdate, and sodium silicomolybdate.

Among these, preferred are colloidal silica, orthosilicic acid, lithium orthosilicate, and water glass. These silicic acid compounds can also be used alone or in combination of two or more.

The coating solution used in the method of the present invention is usually composed of components (a) and (b) in the required ratio in an appropriate solvent at a concentration of 0.0.
05-10-t%, particularly preferably 0.01-5 wt%
Prepare by dissolving or dispersing.

The ratio of component (a) and component (b) in the coating liquid is in the range of 0.1 to 1000 parts by weight (preferably 1 to 600 parts by weight) of component (a) to 100 parts by weight of component (a). This is desirable. If the amount of component (B) is less than 0.1 part by weight or exceeds 1,000 parts by weight relative to 100 parts by weight of component (B), it will be difficult to obtain the effect of using component (-) and (b) in combination, which will reduce the adhesion of scale. cannot be prevented.

The solvent used to prepare the coating solution may be one or a mixture of two or more of water, alcohol solvents, ketone solvents, ester solvents, and the like.

The coating solution obtained as described above is applied to the inner wall of the polymerization vessel and other parts that come into contact with the monomer during polymerization, such as the stirring shaft and the stirrer blades, and dried at a temperature between room temperature and 100°C. By doing so, a coating film is formed to prevent the adhesion of polymer scale.

The method of applying the coating solution to the inner walls of the polymerization vessel, etc. is not limited, and any method such as brushing or spraying may be used, and the amount of application is approximately 0.001 g/n? or more (solid content) especially 0.
It is preferable to set it as 01-2 g/m. 0.001g/
Below rd, the connectivity of the scale prevention effect decreases.

In the present invention, the coating film may be formed for each batch of polymerization, but since the coating film once formed has considerable durability and its scale prevention effect is long-lasting, it is not necessary to form the coating film for each batch. There is no need to do so. Usually 1~
It may be formed for each batch.

Polymerization of vinyl monomers in a polymerization vessel in which a coating film has been previously formed on the inner wall surface of the polymerization vessel as described above is carried out according to a conventional method. That is, for example, water, a vinyl monomer, a polymerization initiator, and other necessary additives such as monomer dispersion aids are charged and polymerized according to a conventional method.

The method of the present invention can be applied to the homopolymerization of vinyl chloride monomers and the copolymerization of vinyl chloride monomers with other vinyl monomers in an aqueous medium. The type of polymerization may be suspension polymerization, emulsion polymerization, solution polymerization, bulk polymerization, or gas phase polymerization.

Examples of vinyl monomers that can be subjected to polymerization include vinyl esters such as vinyl acetate and vinyl propionate, acrylic acid, methacrylic acid, or their esters or salts, maleic acid or fumaric acid, and their esters or anhydrides. , butadiene, chloroprene, and isoprene, as well as styrene, acrylonitrile, vinylidene halide, and vinyl ether.

In these j9J polymerizations and emulsion polymerizations, for example, t-butyl peroxyneodecanate,
Di-2-ethylhexyl peroxydicarbonate, 3
．． 5.5-Trimethylhexanoel peroxide, α
-cumyl peroxyneodecanoate, cumene hydroperoxide, cyclohexanone peroxide, t
- organics such as butyl peroxypivalate, di-2-ethoxyethyl peroxydicarbonate, benzoyl peroxide, lauroyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate and acetylcyclohexyl peroxide. Peroxides, azo catalysts such as α,α′-azobisisobutyronitrile, α,α′-azobis-2,4-dimethylvaleronitrile, water-soluble peroxides such as potassium persulfate, ammonium persulfate, etc. are used. It will be done. Further, as dispersants, for example, partial oxides of polyvinyl acetate, polyacrylic acid, copolymers of vinyl acetate and maleic anhydride, cellulose derivatives such as hydroxypropyl methylcellulose, and natural and synthetic polymer compounds such as gelatin, etc. suspending agents; nonionic emulsifiers such as sorbitan monolaurate, sorbitan triolate;
Emulsifiers such as anionic emulsifiers such as sodium lauryl sulfonate and sodium alkylbenzenesulfonate are used, and other additives include fillers such as calcium carbonate and titanium oxide, tribasic lead sulfate, calcium stearate, dibutyltin dilaurate, and dioctyl. Stabilizers such as tin mercaptide, lubricants such as rice wax, stearic acid, and cetyl alcohol, plasticizers such as DOP and DBP, chain transfer agents such as trichlorethylene and mercaptans, and pHtJj1 moderators are added to the polymerization system. According to the method of the present invention, scale adhesion can be effectively prevented in any polymerization system, regardless of the types of catalysts, dispersants, and additives.

[Effect]

Although the mechanism by which the method of the present invention prevents the adhesion of polymer scale is not clear, it is probably because the coating film made of the mixture of fluorosurfactant and silicic acid compound adheres sufficiently firmly to the wall surface of the polymerization vessel. This is presumed to be due to the effect of preventing specific adsorption of all dissociated molecules and undissociated molecules present in the polymerization system to the inner wall surface of the polymerization vessel during polymerization.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the scope of the present invention is not limited thereto.

The following fluorosurfactants used in the examples below are:
All products are manufactured by Sumitomo 3M and have the following ionic properties.

Florado FC-93 anion FC-95 FC-98'' FC-129 FC-135 cation FC-170C nonion FC-430 FC-431 Example 1 In each experimental floor shown in Table 1, A coating solution having the composition shown in Table 1 was prepared.
A methanol solution is prepared, and the silicic acid compound is dissolved or dispersed in a small amount of water and mixed with the methanol solution. The obtained coating solution was applied to the inner wall of a stainless steel polymerization vessel with an internal volume of 10,001 cm and a stirring shaft, stirring blades, and other parts in contact with the vehicle body, dried at 60° C. for 15 minutes, and then washed with water.

In the polymerization vessel in which the coating film was formed in this way, 400 kg of water was added.
g, 200 kg of vinyl chloride t-tetramer, 250 g of partially saponified polyvinyl alcohol, 25 g of hydroxypropyl methyl cellulose, and 75 g of diisopropyl peroxydicarbonate were charged, and polymerization was carried out at 57° C. with stirring.

After the polymerization was completed, the amount of scale deposited on the inner wall of the polymerization vessel was examined, and the results shown in Table 1 were obtained.

Note that the experimental storms marked with * are comparative examples.

Experimental floor 18, which is a comparative example, used Sudan B/
- Prosin/NazSi04 (weight ratio 100/100/
100)
This is an example using elExp (used in No. 953, elExp, m33).

The degree of coloration of the polymer obtained on each experimental floor was measured as follows.

100 parts of polymer, stabilizer TS-lot (manufactured by Akishima Chemical)
A mixture of 1 part and 0.5 parts of C-100J (Yomikuchi Kako) and 50 parts of plasticizer DOP was kneaded with two rolls at 160°C for 5 minutes, and then made into a sheet with a thickness of 1.
A measurement sample was prepared by placing it in a mold of m x 4c + n x 1.5 cm (thickness) and pressurizing it at 160°C with a pressure of 65 to 70 kg/cut.

The L value of the sample was measured by reflection using a colorimeter ND-1001DP model (manufactured by Nippon Heavy Industries). The obtained L values are also shown in Table 1. The closer the L value is to 1oo, the higher the whiteness and the lower the degree of coloring.

Example 2 A coating liquid having the composition shown in Table 2 was prepared under each experimental light shown in Table 2. That is, 0.5 wt% of fluorosurfactant
The silicic acid compound is dissolved or dispersed in a small amount of water and mixed with the methanol solution. The obtained coating liquid was applied to the inner wall of a glass-lined polymerization vessel equipped with an agitator having an internal volume of 201 mm, and to the agitating shaft, agitating blades, and other parts in contact with the vehicle body, dried at 40° C. for 20 minutes, and then washed with water.

7.5 kg of water was placed in the polymerization vessel in which the coating film was formed.
, methyl methacrylate 4kg, styrene it form 1kg
.

25 g of t-dodecyl mercaptan 1 5 g of polyvinyl alcohol and α,α'-azobisisobutyroni I-IJ
25 g of the polymer was added and polymerized at 80°C for 5 hours.

After the polymerization was completed, the amount of scale deposited on the inner wall of the polymerization vessel was examined, and the results shown in Table 2 were obtained.

Note that the experimental lights marked with * in Table 2 are comparative examples.

Example 3 In each experiment shown in Table 3, the coating liquid shown in Table 3 was used at an internal volume of 20 I! Apply to the inner wall of the stainless steel polymerization vessel, stirring shaft, stirring blades, and other parts that come into contact with the vehicle body, and heat to 50°C.
After drying for 15 minutes, it was washed with water.

9 kg of water, 225 g of sodium dodecylbenzenesulfonate, 12 g of dodecyl mercaptan, and 13 g of potassium persulfate were added to the polymerization vessel in which the coating film was formed in this way.
After purging with nitrogen gas, 1.3 kg of styrene and 3.8 kg of butadiene were charged, followed by polymerization at 50°C for 20 hours.

After the polymerization was completed, the amount of scale adhesion on the inner wall of the polymerization vessel was examined, and the results shown in Table 3 were obtained.

In Table 3, the experimental results marked with * are comparative examples.

〔Effect of the invention〕

According to the method of the present invention, it is possible to effectively prevent the adhesion of polymer scale on the inner wall of the polymerization vessel, the stirrer, and other parts that come into contact with monomers, and this effect is effective in suspension polymerization, emulsion polymerization, and bulk polymerization. In various polymerization methods such as solution polymerization, gas phase polymerization, etc., whether the polymerization vessel is made of stainless steel or glass lined, it is affected by the type of monomer, the composition of the polymerization system, the polymerization catalyst, etc. Kotona (exercised)

Further, the fluorosurfactant and silicic acid compound used as a scale inhibitor in the method of the present invention have the advantage that they are generally colorless and have no risk of contaminating the product.

Claims (1)

[Claims] 1) Applying a coating solution containing (a) a fluorine-based surfactant and (b) a silicic acid compound to the inner wall of the polymerization vessel and other parts of the polymerization vessel that come into contact with monomers during polymerization, and drying. A method for producing a vinyl polymer, which comprises polymerizing a vinyl monomer in a polymerization vessel having a coating film formed by.