JPS6084308A - Polymerization of vinyl chloride monomer - Google Patents

Abstract

PURPOSE:To prevent the deposition of polymer scale on the surface of the inside wall of a polymerization vessel for polymerizing a vinyl chloride monomer, by coating the surface with hydrophilic anionic and cationic dyes with the aid of methylolmelamine and a hydrophilic polymer substance. CONSTITUTION:A hydrophilic anionic dye (e.g., C.I. Acid Orange 7 or C.I. Acid Black 1), a hydrophilic cationic dye (e.g., C.I. Basic Red 2 or C.I. Basic Black 2), methylolmelamine, and a hydrophilic polymer substance (e.g., polyvinyl alcohol or polyacrylamide). The resulting coating solution is applied to the surface of the inside wall of a polymerization vessel and/or the surface of its accessories and then dried. To this polymerization vessel are added a vinyl chloride monomer or a mixture based on this monomer and containing monomers copolymerizatable therewith and an aqueous medium to produce a polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for polymerizing vinyl chloride monomers. More specifically, cyclized vinyl monomers or polyvinyl monomers are the main constituents, and 1 (mixtures with monomers that can be combined) (hereinafter, these are collectively referred to as "vinyl chloride monomers"). When polymerizing this monomer, the polymer obtained by polymerizing this monomer is included in the term "vinyl chloride polymer"). The present invention relates to a method for preventing polymer scale deposition.

Polymerization of the vinyl chloride monomer is carried out by emulsifying the vinyl chloride monomer in an aqueous medium containing an emulsifier or a dispersant in the presence of an offshore initiator. During this polymerization process, the inside wall of the polymerization vessel, the auxiliary equipment of the polymerization vessel such as stirring, baffles, the walls of the reflux condenser, and the walls of various pipes that are attached to the polymerization vessel, etc., are removed. Polymer scale builds up on the parts that come into contact with the body (hereinafter referred to as ``inner walls of the polymerization vessel, etc.'').

As a result, the polymer yield decreases, the cooling capacity of the polymerization vessel decreases, and peeling scales are mixed into the product, resulting in a decrease in product quality (for example, Finnishai). At the same time, excessive labor and time are required to remove the f1m scale, reducing the operating rate of the offshore reactor.Furthermore, when people are in the polymerization reactor trying to remove the adhering scale, the shift is caused by vinyl chloride monomers. Therefore, it is important for the department of manufacturing vinyl chloride polymers to solve these problems.

This has been a long-standing issue.

Conventionally, as a method of preventing polymer scale from adhering to the inner wall of the polymerization vessel, polar compounds such as amine compounds, quinone compounds, and aldehyde compounds (% Kosho Geter 3θ3G No. 3) have been added to the inside of the polymerization vessel.

Methods of applying dyes (% Kosho Guzag! No. 30 and 3■) and free radical inhibitors (Japanese Patent Kokai Sho Guzag No. 32!) are known. 7:))L,Therefore, these methods have the disadvantage that the prevention effect of the scaled layer is insufficient and the sustainability of the prevention effect is low. ′! It's F.
In the method of spreading a mixture of candy, film-forming stool sebum, and a 1-coin inhibitor (percentage opening j--970 ■7), the coating film form and resin are unsuitable for water, so it is unbalanced. It must be dissolved in a bath additive before use, and there are problems with the toxicity and safety of bath additives.

As a result of extensive research in order to solve the problems of conventional methods, the present inventor, Ko et al., developed a method to prevent scale build-up by coating hydrophilic anionic dyes and hydrophilic cationic dyes using methylolmelamine and hydrophilic polymer substances. The present invention was developed by discovering that eggs have a remarkable effect on prevention, and that the prevention effect can be maintained for a long time.

Ta.

That is, an object of the present invention is to industrially advantageously carry out the polymerization reaction of vinyl chloride monomers. Mainly composed of vinyl monomer and copolymerized with it = A mixture with monomer J is not polymerized in an aqueous medium and is referred to as Z, so that it becomes hydrophilic on the inner wall of the polymerization vessel and/or the surface of the equipment attached to the polymerization vessel. sex anion dye kumipj
This is easily accomplished by coating aqueous cationic dyes with methylolmelamine and hydrophilic offshore materials.

The present invention will be explained in more detail below.

In the present invention, only two components, a hydrophilic anionic dye, hydrophilic cationic V, B methylol melamine, and a hydrophilic polymer substance, are coated on the inner wall of a polymerization vessel, etc., and a vinyl chloride monomer is polymerized. In some cases, a sufficient scale adhesion prevention effect cannot be obtained.

When carrying out a one-component reaction of cyclized vinyl yarn monomers by applying hydrophilic anionic dyes and aqueous cationic dyes to the inner wall of the polymerization vessel, etc., it is necessary to apply scales with good relative softness. Although a layer prevention effect can be obtained, the scale adhesion prevention effect disappears in a short time t2. However, as described above, hydrophilic anionic dyes and hydrophilic cationic dyes with low persistence of scale prevention effect and hydrophilic cation dyes are combined with methylolmelamine and hydrophilic polymeric substances according to the method of the present invention. By using it, you can get an excellent 7 hisskel adhesion prevention effect,
;6) It has an unexpected effect of being able to maintain the anti-inflammatory effect for a long time.

The hydrophilic anionic dye used in the method of the present invention may be one that is soluble in water (having sufficient water solubility to be used as a coating solution). OS Weight - Above, Eha, OoI, Acid Orange 7- 0.1. Acid Black/, C9 Engineering, Acid Flu/j, O, I.

Acid green/2, C1 work, direct red, 2
,0. Engineering, Direct Brown/, 0. i, Hydrophilic azo dye such as Direct Yellow/Co, O, i, Acid Black λ, ゛ ・ --... C1 ■, Acid Blue! 2nd class hydrophilic azine dye.

Rad! Hydrophilic xanthine family I, such as A, A, Acid Yellow 3, etc., hydrophilic quinoline dyes, C6 ■.

Acid Yellow 2nd Class Hydrophilic Naphthalimide 'All
Hydrophilic nitro dyes such as C-1, Acid Yellow/etc. are used. The stiffeners may be used alone or in a mixture of two or more.

1. The hydrophilic cationic dye used in combination with the hydrophilic anionic dye may be one that is soluble in water (having sufficient water solubility to be used as a coating solution). , usually o to water, o is heavy Mq6 or more, preferably 0. /Heavy resistance - A material that dissolves at least 10% is used.

Examples of these hydrophilic cationic dyes include C0, Paysic Red 2. C1 engineering, Paysic black λ
Hydrophilic azine dyes such as C0■, Paysic Blue/.

C0■, pasic violet 3. C0 engineering, Paysic Blue! % Hydrophilic triphenylmethane dyes such as C0 Process and Paysic Blue 2, hydrophilic thiazine dyes such as C0 Process and Paysic Bruta, hydrophilic thiazole dyes such as C0 Process and Paysic Yellow/etc., C8■.

Mention may be made of PASIC YELLOW//% hydrophilic methine dyes. These may be used alone or in a mixture of two or more.

Furthermore, examples of methylolmelamine include monomethylolmelamine and dimethylolmelamine.

trimethylolmelamine, tetramethylolmelamine,
Examples include pentamethylolmelamine and hexamethylolmelamine, and b may be used alone or in a mixture of two or more. Further, a condensate of methylolmelamine may be incorporated into the methylolmelamine to the extent that it is soluble in water. Furthermore, alkylated methylolmelamine obtained by alkylating the methylolmelamine with alcohol or the like, such as methylated methylolmelamine, can also be used.

In addition, a hydrophilic polymer substance that reacts with monomethylolmelamine to form a crosslinked polymer substance is used as the hydrophilic polymer substance, and a functional group that can react with the methylol group, imino group, or alkoxy group of methylolmelamine is used. , for example, has a hydroxyl group, a carboxyl group, or an amide group, and.

A hydrophilic material is used. Specific examples include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyethyleneimine, partially saponified polyvinyl acetate, and the like may be used alone or in a mixture of two or more.

In order to apply a hydrophilic anionic dye and a hydrophilic cationic dye to the inner wall of a polymerization vessel using methylolmelamine and a hydrophilic polymer substance according to the method of the present invention, a solution of these components (from a working surface, it is better to use an aqueous solution) is used. Good.

) may be applied singly or in combination to surfaces such as the inner wall of the polymerization vessel, but in order to perform the coating work more efficiently, hydrophilic anionic dyes, hydrophilic cationic dyes, and hydrophilic polymers may be used. The substance is dissolved in water and methylolmelamine is added just before application.

4 is preferably applied as an aqueous solution of a mixture of components. Further, when applying the above-mentioned wiping liquid to a surface such as the inner wall of a polymerization vessel, it is preferable to use an acidic coating liquid. For this reason, when using the lead cloth solution alone, it is best to use a pH adjuster to adjust the aqueous solution containing Fi, a hydrophilic anionic dye, and a hydrophilic cationic dye to a pH value of 2 or less, preferably a pH value or less. In addition, when using the above 4 as a mixture of components, the pH value of the aqueous solution containing the above 4 components is adjusted to 2 or less using a pH adjuster.

It is preferable to use the following pH values.

As the above-mentioned pH adjuster, inorganic acids such as sulfuric acid, nitric acid, and phosphoric acid, hydrophilic organic acids such as acetic acid, lactic acid, and glycolic acid, and acid salts thereof are used.

Furthermore, carbon atoms t are added to the coating solution prepared as described above.
It is preferable to use a monohydric alcohol containing / to -0 weight because it improves the workability of coating the coating solution onto the inner wall of the polymerization vessel, and further improves the effect of preventing scale buildup.

The monohydric alcohols mentioned above include n-phthyl alcohol, 1iso-butyl alcohol, BeQ-butyl alcohol, t-butyl alcohol; n-amyl alcohol, 180-amyl alcohol.

Examples include θeC-amyl alcohol, 1 t-amyl alcohol, n-hexyl alcohol, SθC-hexyl alcohol, and the like. Kowara - It may be used alone or in a mixture of two or more.

The mixing ratio of the above-mentioned components is not particularly limited, but in order to obtain good coating performance, the ratio of water-based anionic dye and hydrophilic cationic dye/methylolmelamine/hydrophilic polymer substance should be adjusted in weight proportions. 10θ/10 to 10θ0/10
It is preferable that it is within the range of ~10θθ. In addition, the ratio of hydrophilic anionic dye to hydrophilic cationic dye is the heavy duty ratio /
It is preferably within the range of θθ//θ to /θθ. In addition, the viscosity and other components that affect joint workability have been reduced to 0.
It is preferable to prepare an aqueous solution containing an amount of /~30M.

This aqueous solution may be applied to the inner wall of the polymerization vessel using a commonly used coating means such as spraying. In coating group A, methylolmelamine and a hydrophilic polymer substance undergo a crosslinking reaction and become water-insoluble, and the hydrophilic anionic dye and hydrophilic cationic dye T-are tightly immersed in the inner wall of the polymerization vessel, etc. let

Although this crosslinking reaction can be carried out by leaving it at room temperature for a long time, it is preferable to accelerate the reaction by heating to lit θ to izo°C.

The amount of the above-mentioned green component applied is usually 1 θ, 0/l/d or more, relative to the surface to which the total amount is applied, i.e., the inner wall of the polymerization vessel, etc.
Preferably 0. It is in the range of O/~ioy/d. If the coating amount is less than 0.0/f/-, scale generation cannot be sufficiently suppressed. In addition, if /Ot/n1 or higher, no increase in the prevention effect can be expected; on the contrary, if the coating material is applied to the wall surface? AM power tends to be weaker.

In the method of the present invention, all commonly known polymerization recipes are used for the polymerization of the vinyl monomer.

The dispersants and emulsifiers used are special polymerization initiators.
A polymerization initiator tube can be used. For example, dispersants and emulsifiers include partially saponified polyvinyl acetate and acrylic acid copolymers.

Maleic anhydride copolymer, cellulose derivative.

Protective colloidal agents such as gelatin, starch, etc.
or 1 natural polymer compound, esters of killed fatty acids and polyhydric alcohols, nonionic surfactants such as polyoxyethylene derivatives, gold pI4 salts of crystalline fatty acids, higher alcohols, etc. Anionic surfactants such as alkali salts of acid esters are used.

Examples of the polymerization initiator include organic peroxides such as benzoyl peroxide, lauroyl peroxide, dioctyl peroxycarbonate, and acetyl Schifte-hexyl sulfonyl peroxide.

Azo compounds such as azobisinbutytetranitrile and dimethylvaleronitrile -'A4jAttm potassium.

Persulfates such as ammonium sulfate can be used.

The vinyl chloride yarn monomer body used in the method of the present invention and the thickened vinyl monomer itself are mainly composed of slimmed vinyl rectangles. It may be a monomer of tM vinyl or a mixture of monomers copolymerizable therewith. Monomers that can be copolymerized include olefins such as ethylene and propylene, vinyl esters such as vinyl acetate and stearin vinyl, vinyl ethers such as ethyl vinyl needle and cetyl vinyl ether, acrylic esters, maleic acid, and Unsaturated carboxylic acid conductors such as fumaric diesters and anhydrides.

Any conventionally known monomers copolymerizable with vinyl chloride, such as aromatic vinyl compounds such as styrene and unsaturated nitrile compounds such as acrylonitrile, can be used.

According to the method of the present invention, during the polymerization reaction, there is no or an insignificant amount of scale attached to the inner walls of the polymerization vessel, so the occurrence of fish eyes etc. in the final processed product is drastically reduced. The quality has improved, and cleaning of the inner walls of the 11. -II becomes noticeably less and continues to be operated for a long period of time without stopping.
The productivity is the same as above, and the cost is extremely low! You can get great results. In addition, operations such as cooling become easier, and a reflux condenser can be used as a new cooling means. The coating substance used in the thin ice invention method is water-soluble and is used after dissolving in water, so the working environment when recovering the solvent when making a temporary phase of the ifM bath agent and drying the coating film. There are no adverse effects such as deterioration of Furthermore, the method of the present invention can be used in cases where the production of scale deposits has been particularly marked in the past, when a polymerization initiator with a low fjμ point, such as t-butylperoxypivanate or diisoglobilperoxydicarbonate, is used. Even when a special auxiliary agent such as sorbitan ester is added for quality improvement, a stable scale adhesion prevention effect is exhibited.

The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example/Methylolmelamine (manufactured by Sumitomo Kaji Co., Ltd., trade name Sumimaru@M-, tOw) was added to a 2% by weight water bath solution of polyethyleneimine.
), a, engineering, acid black λ.

1. Add and mix specific amounts of 0. Polyethyleneimine/wt%,
Methylolmelamine! 1 quantity chi, C1 work, assisted black co, θ, /! An aqueous coating solution having a pH of λJ and containing 0.0 weight % of C0 weight and 0.0 weight weight jl of C0 work and payic proof was prepared. This coating liquid was applied to the inner wall of a stainless steel polymerization vessel with an internal volume of 100 g, using an iron sprayer, to the surface of the stirring blade at a rate of coating liquid ii/00 per area/-.
? Deionized water using a toner/! θ/cl/, partially saponified polyvinyl acetate tOf, m-vinyl heptamer-100k
2.g and t-butyl peroxybivalate were charged, and polymerization was carried out at about 10° C. until a predetermined polymerization rate was reached. After the produced vinyl chloride road coalescing slurry was extracted, the inside of the vessel was washed with water, and after drying, the amount of scale attached was measured. The results are shown in the table below. Furthermore, when the same polymerization as above was carried out in 30 batches, the scale activation amount tllll
All results are shown in the table.

Example - The same procedure as Example was carried out except that polyvinyl alcohol was used instead of polyethyleneimine. The results are shown in Table 1.

Example 3 The same procedure as in Example 3 was carried out except that partially saponified polyvinyl acetate was used instead of polyethyleneimine. The results are shown in Table 1.

Example The same procedure as in Example 1 was carried out except that polyacrylamide was used as the base of polyethyleneimine. The results are shown in Table 1.

Example! 7% by weight of polyethyleneimine as coating liquid.

Methylolmelamine weighs 96.0. Engineering, Acid Blue! From θ, θ' N fit %, O, Engineering, Peisic - / / Total 0,03 Juchi - Chi and n
-butyl alcohol! Heavy gold containing liquid pH2,j
The same procedure as in Example 1 was carried out except that an aqueous solution of was used. Show the results to the public.

Example g Example except that polyacrylic acid was used instead of polyethyleneimine! I did the same thing. The results are shown in Table 1.

Example 7 Partially saponified polyvinyl acetate was used as a coating liquid in an amount of 7% by weight, and methylolmelamine was used in an amount of 7% by weight.

Acid blue jri 0. θrMjtr%, C6 engineering, θ, 0.21 scratch and n-butyl alcohol! Liquid pH containing heavy OS! The procedure was as in Example 1 and Ii'7 except that an aqueous solution of was used.

The results are shown in Table 1.

Example ♂ The same procedure as in Example 2 was carried out except that polyvinyl alcohol was used instead of partially saponified polyvinyl acetate.

The results are shown in Table 1.

Example 2 Polyacrylamide was used as the coating liquid. 0.2. ft finger%, methylolmelamine 7fold-111-thi, a, Z,
Direct green, 2j 0.03 weight 1 inch, C1 construction,
Peisic proof o, oconi # if % and n-butyl alcohol! Liquid pH λ, j
The same procedure as in Example 1 was carried out except that an aqueous solution of was used. The results are shown in Table 1.

Example/θ The same procedure as in Example 1 was carried out except that polyethyleneimine was used as the polyacrylamide base. The results are shown in Table 1.

Example // As coating liquid, polyvinyl alcohol fθ, J′ weight %,
Methylolmelamine! An aqueous solution of gpH-2,-t containing % by weight, CO, Direct Brown/o, i by weight, and C8I, θ, /% by weight of PASIC Red 4 was used. I went in the same way. The results are shown in Table 1.

Example/- Central hl except that partially saponified polyvinyl acetate was used instead of polyvinyl alcohol! The same procedure as Example i// was carried out. The results are shown in Table 1.

Example/3 As a coating liquid, polyvinyl alcohol was used at θ, j% by weight, methylolmelamine was used at -2:i%, c, and Acid Black 2 was used at 0.0%! The procedure was carried out in the same manner as in Example 1, except that an aqueous solution containing 0.0.2% by weight of 0.0.2% by weight of Paysic Yellow was used.

The results are shown in Table 1.

Example/(t) The same procedure as Example 3 was carried out except that polyethyleneimine was used instead of polyvinyl alcohol. The results are shown in Table 1.

Example/! The same procedure as in Example 3 was conducted except that partially saponified polyvinyl acetate was used instead of polyvinyl alcohol.

Show the results to the public.

Fireside 1 IJ/6 1All- was carried out in the same manner as Example/3 except that polyacrylamide was used for d = polyvinyl alcohol. The results are shown in Table 1.

Comparative Example The same procedure as in Example was carried out, except that the coating liquid was not applied at all to the inner wall of the mixing vessel and the surface next to the stirring n. The results are shown below.

Comparative Example The same procedure as in Example 1 was carried out except that an aqueous solution containing 1 M % methylolmelamine and 7 weight % polyvinyl alcohol was used as the coating liquid. The results are shown below.

Comparative Example 3 The same procedure as in Example 3 was carried out except that an aqueous solution containing methylolmelamine tN-di and partially saponified IJDi=M vinyl/Toki% was used as the coating liquid. The results are shown below.

Comparative Example The same procedure as in Example 1-1 was carried out except that a bathing solution containing 3kti% methylolmelamine and polyacrylamide/N was used as the coating solution. The results are shown below.

Comparative example! Methylolmelamine J'M % as coating liquid
The same procedure as in Example 1 was carried out except that an aqueous solution containing % and polyethyleneimine/M needles was used. The results are shown below.

Comparative Example 6 Example except that an aqueous solution of H, 2, θ (sulfuric acid was used as a pH adjuster) was used as a coating solution, and a solution containing 0.2% by weight of C0 coating and acid black λ. I did the same thing as /. The results are shown below.

Comparative Example 2 Polyethyleneimine'er/MAL as coating liquid
%.

Methylolmelamine! Powder containing 0.13% by weight of Acid Black A 1) Aqueous solution of H2,0 (same as Example/except that sulfuric acid 1 was used as the pH adjuster) I did it.

The results are shown below.

Comparative example? Use C6■ and Paysic Flu 9 as coating liquids. , 2% by weight of a water bath solution (p)I having a pH of 2.0. Sulfuric acid was used as an adjuster. The procedure was carried out in the same manner as in Example 7+ except that ) was used, and the results are shown in the second table.

Comparative example? pH of solution containing θ,/-tmit% of Issikku Pluta
Aqueous solution of 2,θ (with pH adjuster and silicate acid)
Example 1 was carried out in the same manner as in Example 1, except that .

The results are shown in Section 26.

Comparative example / θ Coating solution (2 C1 process, Acid Blue! θ, θ by weight and C1 ■, Pacific Yellow // O0O) An aqueous solution of pH, i, θ Sulfuric acid was used for spinning and sharpening.) The rig was carried out in the same manner as in Example 1. The results are shown in Section 26.

Comparative Example // As coating liquids, C, The process was carried out in the same manner as in Example except that a 1L pH-2.0 aqueous solution (sulfuric acid was used as the pH adjuster) was used, containing θ, os weight of PASIC BLUE 2. . The results are shown in Section 26.

Reference example/~6 Example 3. Example/Example/3. Comparative example/.

In Comparative Example 2 and Comparative Example //, the quality of vinyl chloride polymers obtained in specific batch polymerization reactions was evaluated using the methods described below.

100 parts of the obtained vinyl chloride polymer, 50 parts of dioctyl phthalate, and 3 seconds of lead-based stabilizer were thoroughly mixed, and the resulting mixture was rolled at 1°C. There was a mix-up for minutes. λ for the obtained rolled sheet! -I counted the fish-eye nails inside. The results are shown in the third column.

Table 3

Claims (1)

[Claims] (1) When polymerizing vinyl chloride monomer or a mixture of vinyl chloride monomer as a main component and a monomer copolymerizable with it in an aqueous medium, the inner wall of the polymerization vessel and/or the polymerization vessel A method for polymerizing vinyl chloride monomers, which comprises applying a Kfi aqueous anionic dye and a hydrophilic cationic dye to the surface of the appendix using methylolmelamine and a hydrophilic polymer substance.