JPS61235403A - Polymerization of vinyl monomer - Google Patents

Abstract

PURPOSE:To polymerize a vinyl monomer without deposition of polymer scale on the inside surface of a polymerizer, by previously coating the inside surface of the polymerizer with a specified reaction product and polymerizing the monomer in an aqueous medium in the polymerizer. CONSTITUTION:In polymerizing a vinyl monomer in an aqueous medium, the inside surface of the polymerizer is previously coated with a reaction product between a high-molecular halogen compound and a phenolic compound. Examples of the vinyl monomers which can be applied include vinyl chloride and a mixture thereof with a monomer copolymerizable therewith. Examples of the high-molecular halogen compounds include high-molecular chloroalkyl compounds and halopolystyrenes. Examples of the phenolic compounds include phenol, dihydric phenolic compounds and trihydric phenolic compounds obtained by introducing substituents into the compounds.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved method for polymerizing vinyl monomers, and more particularly, to a method for suspending 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 a vinyl monorod is polymerized in the presence of a dispersant or emulsifier and a polymerization initiator, the problem is that solid polymer called scale adheres to the inside surface of the polymerization reactor, that is, its inner wall, stirring blades, baffle plate, condenser, 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 compounds 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 shortcomings 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 No. 55-16004 discloses phenol-aldehyde initial condensates reacted with nitrophenols, and U.S. Pat. No. 4,080.175 discloses self-condensed polyhydric phenols and Naphthol, JP-A-55-54317
The publication describes a condensate of a phenolic compound and an aromatic aldehyde, JP-A No. 55-102610 II K is alginate propylene glycol ester, JP-A No. 55-11
No. 209 discloses a nitrile-containing polymer, JP-A-58-
No. 204006 discloses a method of applying a reaction product of a drying oil or a semi-drying oil, a phenol compound, and optionally an aldehyde to 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. They discovered that scale adhesion can be effectively prevented and completed the present invention.

[Means for solving problems]

That is, the present invention provides a vinyl-based monomer characterized in that, when polymerizing a vinyl-based monomer in an aqueous medium, a reaction product of a high-molecular halogen compound and a phenolic compound is applied in advance to the inner surface of a polymerization vessel. This invention relates to a method for polymerizing monomers.

Polychloromethylstyrene, a copolymer of styrene and chloromethylstyrene, chloromethylated polystyrene, polyepichlorohydrin, a copolymer of epichlorohydrin and ethylene oxide, epichlorohydrin and Terpolymer of ethylene oxide and glycidyl ether, as well as poly-5-bis(chloromethyl)oxetane and polychloromethyl acrylate.

Examples include polymeric chloroalkyl compounds such as polychloroethyl acrylate and polyvinylchloroethyl ether, and halogenated polystyrene such as chloropolystyrene, brominated polystyrene, and lithiated polystyrene.

In addition, phenolic compounds include phenol, resorcinol, catefol, and hydroquinone.

Divalent heptanolic compounds such as bisphenol A, or trivalent heptanolic compounds such as pyrugallol, hydroxyhydroquinone, phloroglucin, and compounds having substituents such as alkyl groups and carboxylic acid groups on the above compounds. can be exemplified.

The method for producing the reaction product of a polymeric halogen compound and a phenolic compound according to the present invention involves using a Friedel-Krach catalyst in a suitable solvent with a polymeric halogen compound and a phenolic compound in the molecule. There are two methods: a reaction method using phenoxyto prepared from the above-mentioned heptanol compound and sodium hydroxide or potassium hydroxide.

Further, as the Friedel-Kraz catalyst, for example, metal halides such as aluminum chloride, zinc chloride, tin chloride, iron chloride, and boron trifluoride are used.

These reactions are carried out at 10-200°C, preferably 40-15°C.
It is carried out at 0° C. for 5 minutes to 10 hours, preferably 1 to 5 hours.

The mixing ratio of the polymeric halogen compound and the phenolic compound is 1 mole of the halogen group, and 1 mole of the halogen group and the unsaturated group each if the molecule contains an unsaturated group.
The phenolic compound IIL is used in a range of 5 to 5 moles, preferably in a range of α8 to 2 moles.

The solvent used in the reaction system is 7Riedel-Cla7.
When using a catalyst, an inert solvent such as acetone, dioxane, methyl ethyl ketone, or methyl isobutyl ketone is suitable; when using a phenoxide, an ether is used in addition to these solvents.

Tetrahydrofuran, dimethyl sulfate oxide, water, etc. are used, but in either case, it is also possible to carry out the reaction without a solvent.

Further, the amount of the Friedel-Kraz catalyst is preferably α01 to 10 parts (L1 to 2 parts used, and further phenoxy The solution is prepared with potassium hydroxide or sodium hydroxide in an equimolar amount to the phenolic compound used.

The descaling agent produced in this manner is used after being dissolved in a hydrocarbon polar solvent or an alkaline solution.

This solution is used by being applied to the surface of the polymerization vessel by a method such as a spraying method or a rinsing method at a ratio of 1 lL019/- to 109/- as a descaling agent per square meter of the surface of the polymerization vessel.

Polymerization of vinyl monomers using 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 partial keticides of polyvinyl acetate, acrylic acid copolymers, cellulose derivatives, gelatin, starch, etc., esters of higher fatty acids and polyhydric alcohols, etc. Anionic surfactants such as oxyethylene derivatives, metal salts of higher fatty acids, and metal salts of alkylbenzenesulfones 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 monomer referred to here is a monomer having a vinyl group, such as 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 esters such as methyl methacrylate, metal salts or esters such as maleic acid and 7-marine, aromatic vinyls such as styrene, dienes such as butadiene, phosphorylene, and isoprene. Examples include monomers such as acrylonitrile and vinyl monomers that can be copolymerized with these monomers.

Moreover, the polymerization temperature is carried out in the commonly used range of 50 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〕

As 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 sample having a molecular weight of 6000 and a degree of chloromethylation of 5 was placed.
100 parts of 0 mol% chloromethylated polystyrene, 80 parts of pyrogallol, and 400 parts of dioxane were charged, stirred to completely dissolve, and heated to 100°C, and 2 parts of argonium chloride was added thereto. It was gradually added and reacted for about 1 hour and 30 minutes.

After the reaction was completed, the reaction product was thoroughly washed with water and dried.

[Reference Example 2] In the same manner as Reference Example 1, in a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, Vitagar p-270
and 120 parts of potassium hydroxide were dissolved in 550 parts of methyl ethyl ketone VCaO°C.

Then, in advance, the specific gravity is 1.38 and the Mooney viscosity is 60 ± 1.
A solution of 0MLI+4 (polyepichlorohydrin 10Ow having a molecular weight of 10 (1°C)) dissolved in 2504% methyl ethyl ketone was added dropwise to react at 80°C for 4 hours.

Thereafter, the product was washed with water and dried in the same manner as in Reference Example 1.

[Comparative Example 1] After charging 250 parts of pure water, 125 parts of partially saponified polyvinyl acetate, and 05 parts of 2.27-azobis-λ4 dimethylvaleronitrile α into a polymerization vessel with an internal volume of 1yy/y, vinyl chloride monomer was added under reduced pressure. 100 parts of the sample was injected.

Next, the mixture was heated to 57° C. with stirring, and when the pressure inside the polymerization vessel decreased by 2 g/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 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 found to be 1so9/-.

[Example 1.2] The products obtained by the methods of Reference Examples 1 and 2 were each
% ethanol solution was sprayed onto the inner surface of the polymerization vessel used in Comparative Example 1, and dried.

The coating amount at this time was α59/-.

Using this polymerization vessel, polymerization reactions were carried out in the same manner as in Comparative Example 1. The polymerization time was 10 hours in both cases, and the amount of scale attached was 49/, / and 5, respectively.
It was 9/l.

[Comparative Example 2] 250 parts of pure water, 5 parts of vinyl acetate, 125 parts of partially saponified polyvinyl acetate, and 2.2'-
After charging 105 parts of azobis-2,4 dimethylvaleronitrile, 100 parts of vinyl chloride monomer was injected under reduced pressure, and then heated to 60°C while stirring, until the pressure inside the polymerization vessel was adjusted to allow the polymerization reaction to occur. From the steady state pressure of 2 to 9/d
When the temperature decreased, 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 found to be 1 cp59/rd.

[Example 4] The products obtained by the methods of Reference Examples 1 and 2 were each
% ethanol/l/solution, and was spray applied to the inner surface of the polymerization vessel used in Comparative Example 2 and dried.

The coating amount at this time was r:L59/-, respectively.

Using this polymerization vessel, polymerization reactions were carried out in the same manner as in Comparative Example 2, and the polymerization times were both a5 hours, and the scale adhesion amount K was approximately 89/i.

Claims (5)

[Claims] (1) When polymerizing vinyl monomers in an aqueous medium,
A method for polymerizing vinyl monomers, which is characterized in that a reaction product of a high-molecular halogen compound and a phenolic 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 polymeric halogen compound is a polymeric chloroalkyl compound. (4) The phenolic compound is a divalent phenolic compound such as phenol and bisphenol A, or
The polymerization method according to claim 1, wherein the polymerization method is a trivalent phenolic compound such as pyrogallol, hydroxyhydroquinone, or phloroglucin. (5) The polymerization method according to claim 3, wherein the polymeric chloroalkyl compound is chloromethylated polystyrene and polyepichlorohydrin.