JPS61233003A - Method for polymerizing vinyl based monomer - Google Patents

Abstract

PURPOSE:To prevent effectively the scale deposit on the inner surface of equipment, by applying a reaction product of a resin obtained from liquid polybutadiene and an alpha,beta-unsaturated carboxylic acid with a phenolic compound previously to the inner surface of a polymerizer in polymerizing a vinyl based monomer. CONSTITUTION:A vinyl based monomer, e.g. ethylene or acrylonitrile, is polymer ized in an aqueous medium, preferably at 30-80 deg.C temperature. In the process, a resin obtained by reacting liquid polybutadiene with an alpha,beta-unsaturated carboxylic acid, e.g. maleic acid, is reacted with a phenolic compound, e.g. pyrogallol or hydroxyhydroquinone, and as necessary a formaldehyde compound, e.g. HCHO, and the reaction product is previously applied to the inner surface of a polymerizer preferably at 0.01-10g/m<2> ratio by the spraying, rinsing methods, etc. EFFECT:The prolonged effect is obtained due to improved adhesion to metal.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the polymerization of vinyl monomers,
More specifically, the present invention relates to a method for preventing scale from forming on the inner surface of a polymerization equipment due to K polymerization of a vinyl monomer in an aqueous medium.

[Conventional technology]

When vinyl monomers are polymerized in the presence of a dispersant or emulsifier and a polymerization initiator, solid polymers called scale adhere to the inside surface of the polymerization reactor, that is, its inner walls, stirring blades, baffle plates, condensers, etc. There are many. This scale reduces heat transfer efficiency.

A decrease in product yield, a decrease in quality due to the contamination of the product with exfoliated scale, and a decrease in productivity due to the wasted effort and time required to remove the scale.

This brings about many disadvantages, such as creating occupational safety and health problems for workers.

In order to solve these problems, there are many disadvantages of preventing scale formation and its adhesion to the polymerization vessel.

In order to solve these problems, many methods have been proposed to prevent scale formation and its adhesion to the polymerization vessel.

For example, there are methods in which dyes, pigments, other polar organic compounds, inorganic acids and their salts, polyvalent metal salts, etc. are applied to the inner surface of the polymerization vessel or added to the aqueous medium, but these methods do not affect their effectiveness. They have various drawbacks, such as poor sustainability and deterioration of product properties.

As a method for improving these methods, a method has also been proposed in which a polymer compound having a functional group that prevents scale formation is coated on the inner surface of the polymerization vessel.

Phenolic compounds have conventionally been used as polymerization inhibitors, and many methods using them have been proposed.

For example, JP-A-55-16004 discloses a product in which a phenol aldehyde initial condensate is reacted with nitrophenols, and U.S. Pat. , JP-A-55-54317 discloses a condensate of a phenolic compound and an aromatic aldehyde, JP-A-55-102610
JP-A No. 58-11209 discloses a nitrile-containing polymer, JP-A-58-204006 discloses a drying oil or semi-drying oil, a phenol compound, and optionally an aldehyde. A method is disclosed in which a reaction product, etc., is applied to the inner surface of a polymerization vessel.

[Problem that the invention seeks to solve]

However, when these methods are used, there are many problems that need to be improved, such as a decrease in the polymerization rate and problems with the sustainability of the descaling effect due to insufficient durability of the coating film. As a result of intensive research aimed at solving these drawbacks, the present inventors have discovered that certain polymeric compounds are effective, particularly in the polymerization of vinyl monomers, and have completed the present invention.

[Means to solve the problem]

That is, in the present invention, when a vinyl monomer is polymerized in an aqueous medium, liquid polybutadiene and α.

By applying a reaction product of a resin reacted with β-unsaturated carboxylic acid (hereinafter referred to as acid-modified resin), a phenolic compound, and optionally an aldehyde compound to the inner surface of the polymerization equipment, A method for polymerizing vinyl monomers that prevents scale adhesion on internal surfaces.

Methods for synthesizing the reaction product of an acid-modified resin, a phenolic compound, and optionally an aldehyde compound used in the present invention include (1) a method of simultaneously reacting an acid-modified resin, a phenolic compound, and an aldehyde; ) A typical method is to react an acid-modified resin with a phenolic compound and then react with an aldehyde compound.% (3) A typical method is to react a phenolic compound with an aldehyde compound and then react with an acid-modified resin. It is.

In the case of method (1) above, the reaction is carried out according to the usual method for producing phenol resins, except that an acid-modified resin is present.

In the case of method (2), first, an acid-modified resin and a phenolic compound are mixed together using an acid catalyst under a nitrogen atmosphere for 50 minutes.
5 minutes to 1 at 0 to 250°C, preferably 100 to 180°C
A modified phenol compound is produced by reacting for 0 hours, preferably 1 to 5 hours. Next, an aldehyde compound is mixed with the above-mentioned modified phenol compound, and then synthesized according to the usual method for producing 7-enol resin.

The acid catalyst used here includes fluorides such as aluminum, boron, iron, zinc, tin, and titanium.

Examples include halides such as chlorides, complex compounds thereof, inorganic acids and organic acids such as hydrochloric acid, sulfuric acid, and para-toluenesulfonic acid.

Furthermore, in the case of method (3), a phenolic compound and an aldehyde compound are reacted in advance according to a conventional method, and then an acid-modified resin is added and heated to obtain a modified phenolic resin. In this case, the reaction temperature is 50
~140''C and a reaction time of 1 to 5 hours are preferably used.

The ratio of the phenolic compound and acid-modified resin used in the production of the phenolic polymer compound in the present invention is usually MA-P to 100 parts by weight of the phenolic compound.
5 to 200 parts by weight of B resin are applied, preferably 5 to 60 parts by weight. The ratio of the phenolic compound to the aldehyde compound is 1 to 1.5 mol, preferably 15 to 1.1 mol, of the aldehyde compound per 1 mol of the phenolic compound.

If the usage ratio is outside this range, the scale adhesion prevention effect will be significantly reduced.

The acid-modified resin used in the present invention is made by combining liquid polybutadiene and α,β-unsaturated carboxylic acid at 150°C to 250°C.
It can be easily produced by heating to °C under a nitrogen atmosphere. The ratio of liquid polybutadiene to α,β-unsaturated carboxylic acid is 5 to 50 parts by weight, preferably 10 to 30 parts by weight of α,β-unsaturated carboxylic acid per 100 parts by weight of liquid polybutadiene. Ru.

The liquid polybutadiene used in the inhibitor of the present invention is liquid or semi-solid at room temperature and has a molecular weight of 200 to ioo, o.
oo Preferably, it has an IQ of 300 to 000. These liquid polybutadienes are produced by living anionic polymerization ([Szwarc, Nature, 17a11
68 (1956), M. Szwarc, “Carb
anion, Living Polymer and
Electron Transfer Process
sses'', Engineering Science Publicis
her engineering nc, lNew York, N, Y, )
and by known methods such as coordination anion polymerization (Japanese Patent Publication No. 46-20495, Japanese Patent Publication No. 48-43084).

Liquid polybutadiene consists of 1.2 bonds, 1
．． There are two types of polybutadiene consisting of 4 bonds, both of which can be used in the present invention, but liquid polybutadiene consisting of 1.2 bonds is preferred.

Furthermore, liquid polybutadiene having a hydroxyl group or a carboxyl group at the terminal group can also be used.

As the α,β-unsaturated fatty acid used in the present invention, maleic anhydride can be exemplified as a typical example.

The phenolic compound used in the present invention may be one that is used as a raw material for ordinary 7-enol resins, such as phenol, cresol,
Monovalent phenols such as P-chlorophenol and xylenol, and resorcinol.

2 such as hydroquinone, catechol, and bisphenol A.
Examples include trivalent phenols such as trihydric phenols, pyrogallol, and hydroxyhydroquinone. In addition, aldehyde compounds can be used as long as they are commonly used (
Examples include formaldehyde, paraformaldehyde, and acetaldehyde.

The phenolic polymer compound synthesized in this way is
Used by dissolving in a hydrocarbon polar solvent.

This solution is applied by spraying, rinsing, or other methods at a rate of LO19/rr? to 109/lr?c polymer per square meter of the target polymerization vessel surface.

Polymerization of the vinyl monomer used in the present invention includes suspension polymerization,
Emulsion polymerization is employed. The dispersant used in this polymerization,
There are no particular restrictions on the emulsifier, initiator, etc., and commonly used ones can be used.

For example, dispersants and emulsifiers include partially saponified polyvinyl acetate, acrylic acid copolymers, cellulose derivatives,
Anionic surfactants such as protective colloidal compounds such as gelatin and starch, esters of higher fatty acids and polyhydric alcohols, anionic surfactants such as polyoxyethylene derivatives, metal salts of higher fatty acids, and metal salts of alkylbenzenesulfonic acids. Agents are used.

As polymerization initiators, organic peroxides such as benzoyl peroxide, lauroyl peroxide, and dioctyl peroxydicarbonate, azo compounds such as azobisisodimethylvaleronitrile, and persulfates such as potassium persulfate and ammonium persulfate are used. be done.

The vinyl monomers mentioned here are monomers having a vinyl group, such as olefins such as ethylene and propylene, vinyl halides such as vinyl chloride and vinylidene chloride, and vinyl esters such as vinyl acetate. , vinyl ethers such as ethyl vinyl ether, acrylic acid ethers such as methyl methacrylate, metal salts or esters such as maleic acid and fumaric acid, aromatic vinyls such as styrene, diene monomers such as butadiene, chloroprene, isoprene, etc. Examples include acrylonitrile, acrylonitrile, etc.

The polymerization temperature used is a commonly used range of 30°C to 80°C.

Although the present invention can be used for the polymerization of the above-mentioned vinyl monomers alone or a mixture of two or more vinyl monomers, it is particularly effective in polymerizing monomers mainly composed of vinyl chloride. .

〔Effect of the invention〕

According to the present invention, scale adhesion can be significantly prevented, and since it has excellent adhesion to metals, it can provide a long-lasting effect.

〔Example〕

The present invention will be specifically explained below using Examples.

Reference Example 1 80 parts by weight of 1.2-liquid polyptadiene having a molecular weight of 3,000 and 20 parts by weight of maleic anhydride were placed in a four-piece flask and reacted at 200° C. for 4 hours under a nitrogen atmosphere, resulting in a brown compound.

(MA-FB) The reaction temperature was lowered to 150"C, 100 parts by weight of pyrogallol and 1 part by weight of halatoluenesulfonic acid were charged, and the reaction was carried out in a nitrogen atmosphere for 4 hours. After the reaction was completed, it was cooled to below 100°C. Then, 600 parts of water was added to dehydrate, wash, and dry to obtain a reaction product.

Reference example 2 100 parts by weight of pyrogallol in a four-flask.

50 parts by weight of an acidic resin synthesized in the same manner as in Reference Example 1.

Add 1 part by weight of aluminum chloride and add 16 parts by weight under nitrogen atmosphere.
After reacting at 0° C. for 1 hour, the mixture was cooled, 75 parts by weight of formaldehyde (35% concentration) was added, and the reaction was carried out under reflux for 1 hour. Next, 500 parts by weight of water was added to dehydrate, wash, and dry to obtain a reaction product.

Reference example 5 100 parts by weight of pyrogallol in a four-flask.

68 parts by weight of formaldehyde (35% concentration).

2,000 parts by weight of 50 tyric acid was reacted at 60°C for 1 hour to obtain a reddish-purple precipitate. This precipitate was dehydrated and dried. This 100 parts by weight and 50 parts by weight of the acid-modified resin were reacted in the same manner as in Reference Example 1 to obtain a product.

Reference example 4 100 parts by weight of pyrogallol in a four-piece flask.

75 parts of formaldehyde (concentration 55%), 50 parts of acidic resin
Parts by weight of oxalic acid dihydrate dihydrate were charged, and the reaction was carried out for 4 hours under a nitrogen atmosphere. The reaction temperature was controlled by refluxing and condensing the water in the system.

After the reaction was completed, 400 parts by weight of water was added, and after dehydration and washing,
The reaction product was obtained by drying.

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

Example 1 A triple solution of the reaction product obtained in Reference Example 1 in acetone was prepared, sprayed onto a stainless steel polymerization vessel having a volume of 10,004 mm, and dried. The amount of coating at this time is Q, 49
/rrl.

9. Add 200% vinyl chloride to this polymerization vessel. Pure water 4001c9
150 g of partially saponified polyvinyl acetate and 609 g of azobisisodimethylvaleronitrile were added, and polymerization was carried out at 57° C. for 9 hours with stirring. After the polymerization was completed, the amount of scale attached was measured, and the results shown in Table 1 were obtained.

Examples 2 to 5 Polymerizations similar to those in Example 1 were carried out using the reaction products obtained in Reference Examples 2 to 5 instead of the reaction products obtained in Reference Example 1. The results are shown in Table 1.

Example 6 A 3-weight acetone solution of the reaction product obtained in Reference Example 1 was prepared, spray-coated onto a stainless steel polymerization vessel having a capacity of 1000 tons, and dried. The amount of coating at this time is IIL5/W? Met.

Into this polymerization vessel, vinyl chloride #190kg, acetic acid hydrogen = tv1
1C9, pure water 45019. Partially saponified polyvinyl acetate 1
80 g and 60 g of azobisdimethylvaleronitrile were added, and polymerization was carried out at 57°C for 10 hours with stirring. After the polymerization was completed, the amount of scale attached was measured, and the results shown in Table 2 were obtained.

Examples 7 to 10 Polymerizations similar to those in Example 6 were carried out using the reaction products obtained in Reference Examples 2 to 5 instead of the reaction products obtained in Reference Example 1. The results are shown in Table 3.

Practical Example 11 A 3% by weight acetone solution of the reaction product obtained in Reference Example 1 was prepared, sprayed and dried in a stainless steel polymerization vessel with a capacity of 1000 t.The amount of coating was (13 g/
-It was.

This polymerization vessel pressure chloroprene 20019. Polyoxystyrene beef tallow alkylpropylene diamine 8 to 9° acetic acid 2 to 9. Alumina sol 1J9. Sodium formaldehyde sulfoxylate 11.04 to 9. Add 200 kg of pure water and heat at 40°C to dissolve t-butyl hydroperoxide 10
Polymerization was completed in 10 hours while adding 9 to 2. After the polymerization was completed, the amount of scale attached was measured, and the results shown in Table 943 were obtained.

Examples 12 to 15 Polymerizations similar to those in Example 11 were carried out using the reaction products obtained in Reference Examples 2 to 5 instead of the reaction products obtained in Reference Example 1. The results are shown in Table 3.

Comparative Examples A, B, C An aqueous solution containing parts of pyrogallol 126f and 85 parts by weight of formaldehyde (concentration 35%) was added to 2000 parts by weight of a 50 wt% phosphoric acid aqueous solution and reacted at 60°C for 1 hour to form a water-insoluble solid. I got it. After washing this solid with water and drying, it was made into a 3-thiacetone solution, spray-coated, and dried. The coating amount at this time was [1L4g/ze].

Comparative example A is Examples 1 to 5, and comparative example B is Examples 6 to 10.
In Comparative Example C, polymerization was carried out under the same conditions as Examples 11 to 15. The results are shown in the table in comparison with Examples.

Table 1 Table 3 As described above, in each of the examples, the number of effective batches was improved by significantly reducing the amount of scale adhesion and improving the durability of the coating film compared to the comparative example.

Claims (4)

[Claims] (1) When polymerizing vinyl monomers in an aqueous medium,
A vinyl monomer characterized in that a reaction product of a resin obtained by reacting liquid polybutadiene with an α,β-unsaturated carboxylic acid, a phenolic compound, and optionally an aldehyde compound is applied to the inner surface of the polymerization equipment in advance. How the body polymerizes. (2) The polymerization method according to claim 1, wherein the vinyl monomer is vinyl chloride alone or 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 hydroxyhydroquinone. (4) The polymerization method according to claim 1, wherein the α,β-unsaturated carboxylic acid is maleic anhydride.