JPS61247710A - Polymerization of vinyl monomer - Google Patents

Abstract

PURPOSE:To prevent polymer scale from being deposited on the surface of a polymerization reactor, by precoating the surface with a reaction product between a hydrocarbon resin and a phenolic compound and polymerizing a vinyl monomer in an aqueous medium in the reactor. CONSTITUTION:In polymerizing a vinyl monomer in an aqueous medium, the inside surface of the polymerization reactor is precoated with a reaction product among a hydrocarbon resin, a phenolic compound and, optionally, an aldehyde compound. Examples of the vinyl monomers used, which are monomers having a vinyl group, include monomers such as olefins, vinyl esters, acrylate esters, aromatic vinyl compounds, diene monomers, and acrylonitrile and vinyl monomers copolymerizable therewith. Examples of the phenolic compounds include cresol, resorcinol, pyrogallol and hydroxyhydroquinone.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improved method for polymerizing vinyl monomers, and more particularly, to a method for polymerizing vinyl monomers using an aqueous medium. The present invention relates to a polymerization method for preventing the deposition of polymer scale on the inner surface of a polymerization reactor during polymerization or emulsion polymerization.

[Conventional technology]

When vinyl yarn monomers are polymerized in the presence of a dispersant or emulsifier and a polymerization initiator, there is a problem in which 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 is.

This scale causes a decrease in heat transfer efficiency, a decrease in product yield, a decrease in quality due to the contamination of exfoliated scale into the product, a decrease in productivity due to the labor and time required for removing the scale, and occupational safety and health. This causes many disadvantages due to the above problems.

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; They have 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. Japanese Patent Publication No. 55-5451
No. 7 discloses a condensate of a phenolic compound and an aromatic aldehyde, and JP-A-55-102610 discloses a reaction product of alginate propylene glyfur varnish oil or semi-drying oil with a 7-Nol compound and, if necessary, an aldehyde. , etc. are disclosed on the inner surface of a polymerization vessel.

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.

[Problem that the invention seeks to solve]

As a result of intensive research in order to eliminate these drawbacks, the present inventors have discovered that certain polymeric compounds, especially vinyl monomers, can be applied to the inner surface of the polymerization vessel during polymerization. The present invention was completed after discovering that scale adhesion can be significantly prevented and adhesion to metals is extremely excellent.

[Means for solving problems]

That is, in the present invention, when a vinyl monomer is polymerized in an aqueous medium, a reaction product of a hydrocarbon resin, a 7-Nol compound, and optionally an aldehyde compound is applied to the inner surface of the polymerization vessel in advance. This invention relates to a method for polymerizing vinyl monomers that prevents scale adhesion on the inner surface of polymerization equipment.

The method for synthesizing the reaction product of a hydrocarbon resin, a phenolic compound, and optionally an aldehyde compound used in the present invention includes (11) a method of simultaneously reacting a hydrocarbon resin, a 7-phenol compound, and an aldehyde compound. ,(
2) A method of reacting a hydrocarbon resin with a hexaphenolic compound, and then reacting it with an aldehyde compound; (3) A method of reacting a phenolic compound with an aldehyde compound;
A typical method is to react a hydrocarbon resin.

In the method (1) above, the reaction is carried out according to the usual method for producing a 7-enol resin, except for the coexistence of a hydrocarbon resin.

In addition, in the case of method (2), first the hydrocarbon resin and 7
and a ethanolic compound under a nitrogen atmosphere using an acid catalyst.
0 to 250°C, preferably 100 to 180°C, 5 minutes to 1
The reaction is carried out for 0 hours, preferably 1 to 5 hours. Next, after mixing an aldehyde with the above-mentioned modified phenol compound, it is synthesized according to the usual method for producing 7-enol resin.

The acid catalyst used here is aluminum.

Examples include metal halides such as fluorides or chlorides such as boron, iron, zinc, and titanium, or complex compounds thereof, as well as inorganic acids and organic acids such as hydrochloric acid, sulfuric acid, and p-)luenesulfonate.

Furthermore, in the case of method 31, a modified phenolic resin is obtained by reacting a phenolic compound and an aldehyde compound in advance by a conventional method, and then adding a hydrocarbon resin and heating.

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

The ratio of the hydrocarbon resin and the heptadol compound used in the production of the phenolic polymer compound in the present invention is as follows:
Generally, 5 to 200 parts, preferably 5 to 60 parts of hydrocarbon resin are applied to 100 parts of phenolic compound.

City Na 7. Are you pregnant? Regarding the ratio of V-lue supply, the aldehyde compound (L1 to 5 moles, preferably 05 to 1.1 moles) is used per 1 mole of the phenolic compound.

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

The hydrocarbon resin used in the present invention can be prepared by adding 4 fractions or α, β unsaturated carboxylic acid to the − fraction as needed, and then producing 7
60 at a temperature of 10 to 80°C with a Riedel Kushikura 7-type catalyst.
It can be obtained by polymerizing for minutes to 10 hours.

Further, the resin obtained in this manner can also be further modified with carboxylic acid or hydroxyl group and used in the present invention.

A distillate is a fraction with a boiling point of 30% obtained during thermal decomposition of petroleum.
It is a distillate whose main components are olefins and diolefins such as isoprene, piperylene, pentene, and methylbutene at ~80°C.

The term “fraction” refers to the boiling point range 14 obtained during thermal decomposition of petroleum.
Styrene, methylstyrene at 0-280℃.

This is a fraction containing unsaturated hydrocarbons such as indene.

Examples of α,β unsaturated carboxylic acids include maleic anhydride and derivatives thereof. Many of these hydrocarbon resins are commercially available.

The hydrocarbon resin used in the present invention has a molecular weight of 300 to IQ
,000 preferably 500-1. Bromine number is 2 in OOO
0-3009/io0g preferably 5o-zaag71
There are no other quality restrictions on the Aa resin. The phenolic compounds used in the present invention may be those that are used as raw materials for ordinary phenolic resins, such as phenol, cresol, p
- Monovalent phenolic compounds such as chlorophenol and xylenol, resorcinol, hydroquinone, catechol,
Examples include divalent heptanols such as bisphenols, trivalent heptanols such as bilogaquaryl, and human tetraxyhydroquinone.

Further, the aldehyde compound' may be any commonly used aldehyde compound, such as formaldehyde, paraformaldehyde, acetaldehyde, and the like.

The descaling agent produced in this manner is used after being dissolved in a hydrocarbon polar solvent. This solution is applied as a descaling agent per square meter of the target polymerization vessel surface.
It is used by being attached to the surface of the polymerization vessel by a method such as a spray method or a rinsing method so that the ratio is t9/- to 1/m'.

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

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

Benzoyl peroxide is used as a polymerization initiator.

Organic peroxides such as lauroyl peroxide and dioctyl peroxydicarbonate, azo compounds such as azobisisodimethylvaleronitrile, and persulfates such as potassium persulfate and ammonium persulfate are used. The vinyl monomers mentioned here are monomers having a vinyl group, such as olefins such as ethylene and propylene, acrylic esters such as vinyl chloride and methyl bimethacrylate, maleic acid, fumaric acid, etc. metal salts or esters, aromatic vinyls such as styrene, butadiene.

Examples include diene monomers such as chloroprene and isoprene, monomers such as acrylonitrile, and vinyl monomers that can be copolymerized with these monomers.

Further, the polymerization temperature is carried out within the commonly used range of 30-10°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〕

By the method described above, scale adhesion can be significantly improved.

〔Example〕

The present invention will be specifically explained below with reference to Examples.
This is not intended to limit the scope of the invention.

[Reference Example 1] In a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, a mixture with a molecular weight of 900 and a bromine number of 60 (9/100
9), 100 parts of a hydrocarbon resin with a softening point of 60°C (-based petroleum resin commercially available), 100 g of pyrogallol, and 1 part of p-)luenesulfonic acid were charged, and the reaction was carried out for 4 hours under a nitrogen atmosphere at a reaction temperature of 150°C. went.

After the reaction was completed, the mixture 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] Similarly to Reference Example 1, pyrogallol 100 was placed in a four-neck flask equipped with a stirrer, a thermometer, and a reflux condenser.
1 part, 50 parts of the hydrocarbon resin used in Reference Example 1, and 1 part of aluminum chloride were charged with nitrogen [Reference Example 3] In the same manner as Reference Example 1, a four-necked 7-mouth tube was equipped with a stirrer, a thermometer, and a reflux condenser. Pyrogallol 100 in Rasuf
68 parts of 35% formaldehyde and 2000 parts of 50% phosphoric acid were reacted at 60° C. for 1 hour to obtain a reddish-purple precipitate.

100 parts of the precipitate obtained by dehydrating and drying this and 50 parts of the hydrocarbon resin washed in Reference Example 1 were reacted in the same manner as in Reference Example 1 to obtain a product.

[Reference Example 4] In the same manner as Reference Example 1, pyrogallol 100
1, 75 parts of formaldehyde at a concentration of 55%, 50 parts of the hydrocarbon resin used in Reference Example 1, and 2 parts of Scheler's acid dihydrate were charged, and a reaction was carried out for 4 hours under a nitrogen atmosphere.

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

After the reaction was completed, 400 parts of water was added, dehydrated, washed, and 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] 250 parts of pure water, 125 parts of partially saponified polyvinyl acetate, and 5 parts of 2,21-azobis-2,4dimethylvaleronitrile cL0 were charged into a polymerization vessel with an internal volume of 1 m, and then chlorinated under reduced pressure. 100 parts of vinyl monomer were injected.

Next, the temperature was heated to 57°C with stirring, and the pressure inside the polymerization vessel was reduced from the steady state pressure of the polymerization reaction to 29/crIt.
At the bottom, recovery of unreacted monomers was started.

The polymerization time at this time was 10 hours.

After collecting unreacted monomers, the polymerization suspension was taken out from the polymerization vessel, and the inner surface was washed with low-pressure water.

Thereafter, the amount of scale adhering to the inner surface of the polymerization vessel was measured, and the results are shown in Table 1.

[Comparative Example 2] An aqueous solution containing 126 parts of pyrogallol and 85 parts of formaldehyde with a concentration of 35% was mixed with 200 parts of a 50% by weight aqueous solution of phosphoric acid.
0 parts and reacted at 60° C. for 1 hour to obtain a water-insoluble solid. This solid was washed with water and dried, then made into a 3% acetone solution, sprayed onto the inner surface of the polymerization vessel used in Comparative Example 1, and dried.

The amount of application at this time is [lL4ri/? It was F/.

Using this polymerization vessel, a polymerization reaction was carried out in the same manner as in Comparative Example 1. The polymerization time was 10 hours, and the amount of scale deposited 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 each solution was spray coated onto the inner surface of the polymerization vessel used in Comparative Example 1 and dried.

The coating amount at this time was α49/-.

Using this polymerization vessel, polymerization reactions were carried out in the same manner as in Comparative Example 1. The polymerization times were 10 hours in both cases, and the amounts of scale deposited were as shown in Table 1.

[Comparative Example 3] After charging 250 parts of pure water, 5 parts of vinyl acetate, 25 parts of partially saponified polyvinyl acetate α, and 0.05 part of 2.21-azobis-λ4 dimethylvaleronitrile into a polymerization vessel with an internal volume of 1. , injecting 100 parts of vinyl chloride monomer under reduced pressure,
Next, the mixture was heated to 60° C. with stirring, and when the pressure inside the polymerization vessel decreased by 2iai/d from the pressure in the steady state of the polymerization reaction, recovery of unreacted monomers was started.

The polymerization time at this time was a5 hours.

After collecting unreacted monomers, the polymerization suspension was taken out from the polymerization vessel, and the inner surface was washed with water.

Thereafter, the amount of scale adhering to the inner surface of the polymerization vessel was measured, and the results are shown in Table 2.

[Comparative Example 4] The solid obtained by the method of Comparative Example 2 was made into a 3% acetone solution, sprayed onto the inner surface of the polymerization vessel used in Comparative Example 5, and dried.

The amount of coating at this time is α59/lt? Met.

When a polymerization reaction was carried out in the same manner as in Comparative Example 3 using this polymerization vessel, the polymerization time was a5 hours, and the amount of scale deposited was as shown in Table 2.

[Examples 6 to 10] Each of the products obtained by the methods of Reference Examples 1 to 5 was made into a 3% acetone solution, and sprayed onto the inner surface of the polymerization vessel used in Comparative Example 3 and dried.

The coating amount at this time was α59/a.

Using this polymerization vessel, polymerization reactions were carried out in the same manner as in Comparative Example 5. Both polymerization times were &5 hours, and the amounts of scale deposited were as shown in Table 2.

[Comparative Example 5] Internal volume 1? After charging 100 parts of pure water, 100 parts of chloroprene, 4 parts of polyoxystyrene tallow alkylpropylene diamine, 1 part of acetic acid, 5 parts of alumina sol α, and 2 parts of sodium formaldehyde sulfoxylate (ClO) into a polymerization vessel of F/, the mixture was heated at 40°C. Polymerization was completed in 10 hours while adding 101 parts of 1-butyl hydroperoxide.

After completion of polymerization, measure the amount of scale adhering to the inner surface of the polymerization vessel.1.
[Comparative Example 6] The solid obtained by the method of Comparative Example 2 was made into a 3% acetone solution and placed on the inner surface of the polymerization vessel used in Comparative Example 5. Spray applied and dried.

The amount of coating at this time is [L59/rr? T: Yes.

Using this polymerization vessel, a polymerization reaction was carried out in the same manner as in Comparative Example 5, and the amount of scale deposited 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 the solutions were spray coated onto the inner surface of the polymerization vessel used in Comparative Example 5 and dried.

The coating amount at this time was α39/a.

Using this polymerization vessel, polymerization reactions were carried out in the same manner as in Comparative Example 5, and the amounts of scale deposited were as shown in Table 5.

As shown in Table 1 and Table 3, in all Examples, the amount of scale deposited was significantly reduced and the durability of the coating film was improved, resulting in an improvement in the number of effective batches compared to the Comparative Example.

*1 The effective batch number in the table refers to the fact that the scale adhesion prevention effect is lost because the applied scale adhesion preventive agent is peeled off by slurry agitation due to polymerization, and it is not practical to wash any more than this because it has a negative effect on quality such as foreign matter 9 hue. Characterized by the number of batches that can be used effectively until it is no longer possible to continue the polymerization without work

Claims (3)

[Claims] (1) When polymerizing vinyl monomers in an aqueous medium,
A method for polymerizing vinyl monomers, characterized in that a reaction product of a hydrocarbon resin, a phenolic compound, and optionally an aldehyde compound is applied to the inner surface of a polymerization vessel in advance. (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 hydroxydroquinone.