JPS61181802A - Polymerization of vinyl monomer - Google Patents

Abstract

PURPOSE:To polymerize a vinyl monomer while preventing scale deposition, by previously applying a specified compound to the inside surface of a polymerizer and polymerizing the monomer in an aqueous medium therein. CONSTITUTION:A vinyl monomer is polymerized in an aqueous medium, in a polymerizer with its inside surface being previously coated with a reaction product among a hydroxystyrene polymer, a polyphenol compound and an aromatic aldehyde compound. The hydroxystyrene polymer used is synthesized from an o-, m- or p-hydroxystyrene. A commercially available oxime polymer of a MW of about 1,000-40,000 can also be suitable used. Although diphenol compounds such as catechol and bisphenol A, triphenols such as pyrogallol and phloroglucinol, etc., can be used as said polyphenols, the use of non- substituted benzaldehyde is the most advantageous cost wise.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for the polymerization of vinyl monomers, and more particularly to a process for the suspension or emulsion polymerization of vinyl monomers using an aqueous medium. The present invention relates to a polymerization method for preventing the formation of polymer scale on the inner surface of polymerization reaction equipment.

When a vinyl monomer is polymerized in the presence of a dispersant or emulsifier and a polymerization initiator, the inner surface of the polymerization reactor, that is, its inner wall.
Stirring blade, puffle plate. A solid polymer called scale often adheres to condensers and the like.

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 This brings about many disadvantages, such as causing occupational safety and health problems.

[Conventional technology]

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

For example, dyes, pigments and other polar organic compounds.

There are methods of applying inorganic acids and their salts, polyvalent metal salts, etc. to the inner surface of the polymerization vessel or adding them to the aqueous medium, but these methods have problems with the sustainability of their effects and may damage the original product. It has various drawbacks such as deterioration of characteristics.

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 a product in which a phenol aldehyde initial condensate is reacted with nitrophenols, and U.S. Pat. No. 4,080,175 discloses
Self-condensed polyhydric phenols and polyhydric naphthols, JP-A-55-54317, condensates of phenolic compounds and aromatic aldehydes, JP-A-55-102,610
The publication contains alginate furopylene gelicol ester,
JP-A-55-11209 discloses a nitrile-containing polymer, JP-A-58-204006 discloses a drying oil or
A method is disclosed in which a reaction product of a semi-drying oil, a phenol compound, and optionally an aldehyde is applied 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.

[Structure of the invention]

The inventors of the present invention have carried out intensive research to solve these drawbacks, and have found that the rice polymer compound, especially when vinyl monomers are polymerized, can be applied to the inner surface of the polymerization vessel and polymerized. The present invention was completed after discovering that adhesion can be significantly prevented and the adhesion to metals is extremely excellent.

That is, in the present invention, when a vinyl monomer is polymerized in an aqueous medium, a reaction product of an oxystyrene polymer, a polyhydric phenolic compound, and an aromatic aldehyde compound is applied to the inner surface of the polymerization reactor in advance, and then The present invention relates to a method for polymerizing vinyl monomers, which is characterized by polymerization.

The polymer compound used in the present invention is prepared by mixing the oxystyrene polymer, polyphenolic compound, and aromatic aldehyde in an aqueous medium or an organic solvent using an acid catalyst at a temperature of 40°C.
"It is obtained as a reaction product co-condensed in the range of 0 to 200°C.

The oxystyrene polymer that can be used in the present invention is 〇-+
” * p-oxystyrenes can be prepared by a known method, for example 1.
.

J, Polym, Sci, A 4, 177 S (
(1965). Also, the molecular weight is 1000
Commercially available oxystyrene polymers of about 40,000 to 40,000 can also be suitably used.

Catechol is a polyhydric phenolic compound.

Divalent phenolic compounds such as resorcinol, hydroquinone, bisphenol A, and pyrogallol.

Trivalent phenolic compounds such as hydroxyhydroquinone and 70roglucin can be used.

As the aromatic aldehyde, an aldehyde having a benzene nucleus substituent can be used, but the use of unsubstituted benzaldehyde is most advantageous in terms of cost.

The range is from 9/1 to 1/9, preferably from 7/3 to 3.
Can be used within the range of /7. The amount of aromatic aldehyde used is from IIL1 to 1 mole of polyhydric phenolic compound.
It is used in a range of 1 mol.

As the acid, sulfuric acid, hydrochloric acid, phosphoric acid, etc. are used.

The polymer compound synthesized in this manner is used after being dissolved in a hydrocarbon polar solvent or an alkaline solution.

This solution was applied to CLO19/rr per square meter of the surface of the polymerization vessel. ~109/n? It is used by attaching it by a method such as a spray method or a rinsing method so that the ratio is as follows: (as a polymer).

Polymerization of vinyl monomers using 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 protective colloidal compounds such as partially saponified polyvinyl acetate, acrylic acid copolymers, cellulose derivatives, gelatin, and starch, esters of higher fatty acids and polyhydric alcohols, and polyvinyl acetate. Anionic surfactants such as oxyethylene derivatives, 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 may be used.

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, chlorobrene, isoprene, etc. Examples include acrylonitrile, acrylonitrile, etc.

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

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

The present invention will be specifically explained below using Examples.

[Reference Example 1] A commercially available oxystyrene polymer (A) 64 having a molecular weight of about 2000 was placed in a 1 ton stirrer and a reflux condenser-equipped Mitsuro flask.
g, pyrogallol (B) 32, benzaldehyde (C
)449. Phosphoric acid 1189. Add pure water 4009,
The oil bath was heated to 120"C and the reaction was carried out for 6 hours. After the reaction was completed, the product was washed with water and dried.

[Examples 1 to 5] A polymer compound was synthesized by the method shown in Reference Example 1 in a stainless steel polymerization vessel having a capacity of 1000 t, and the 3-thiacetone solution was spray-coated and dried. At this time, the coating amount is (:L5
It was 97-.

Vinyl chloride 200J9. Pure water 400J9° Partially saponified polyvinyl acetate 1509. 60 g of azobisisodimethylvaleronitrile was 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 6 to 10] The 4-thiacetone solution of the polymer compound used in Examples 1 to 5 was spray applied to a stainless steel polymerization vessel having a capacity of 1000 t, and dried. The coating amount was α49/-.

This polymerization vessel contained 190 kg of vinyl chloride and 1 kg of vinyl acetate.
019, 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 11 to 15] A 5% acetone solution of the polymer compound used in Examples 1 to 5 was spray applied to a stainless steel polymerization vessel having a capacity of 1000 t, and dried. The coating amount was [1,32/i].

Chloroprene 200 Jc9. Polyoxystyrene tallow alkylpropylene diamine 8kg.

Acetic acid 21C9, alumina sol 1 and 9. Sodium formaldehyde sulfoxylate α04119. H water 20
0 → was added, and the polymerization was completed in 10 hours while adding 9 to t-butyl hydroperoxide a and 02 at 40"C. After the completion of polymerization, the amount of scale attached was measured, and the results shown in Table 3 were obtained. Ta.

[Comparative Examples A, B, C] 126 parts by weight of pyrogallol and formaldehyde (concentration 3
An aqueous solution containing 85 parts by weight of phosphoric acid was added to 2000 parts by weight of an aqueous solution of 50 parts by weight of phosphoric acid, and the mixture was reacted at 60"C for 1 hour to obtain a water-insoluble solid. After washing this solid with water and drying, it was added with 3% acetone. It was made into a solution, spray coated, and dried.The coating amount at this time was (L49/lr?).

Comparative example A is Examples 1 to 5, and comparative example B is Examples 6 to 10.
and Comparative Example C were polymerized under the same conditions as Examples 11-15.

The results are shown in the table in comparison with Examples.

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

Umbrella 1 The effective number of patches 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 that foreign substances 9 have a negative effect on quality (such as hue). Applicant for a patent characterized by the number of batches that can be effectively used until polymerization cannot be continued without further cleaning procedures Toyo Machida Kogyo Co., Ltd. Procedural Amendment (Method) % Formula % 1 Incident Display 1985 Patent Application No. 20911, Name of the invention: Polymerization method for vinyl-based monohung bodies 3. Matters to be amended (1) Relationship with patent applicant: Toyo Soda Kogyo Co., Ltd. Patent information department Telephone number: (505) 4471 4: Date of amendment order: 1985 May 8, 1985 (Shipping date: 5 J128, 1985)
5) Detailed explanation of the invention in the specification subject to amendment 6 Contents of the amendment (1) Description in lines 1 to 3 on page 6 of the specification, ``For example...
...can be synthesized. ” as follows: Correct.

[For example, Journal of American Chemical Society
Chemical 5ociety) Li.

402 (1949), Journal of PolymerSc.
ience) A4, 1773 (1963)
It can be synthesized by ”

Claims (5)

[Claims] (1) When polymerizing vinyl monomers in an aqueous medium,
A method for polymerizing vinyl monomers, which comprises applying a reaction product of an oxystyrene polymer, a polyhydric phenol compound, and an aromatic aldehyde compound to the inner surface of a polymerization reactor in advance, and then polymerizing the product. (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 or 2, wherein the polyhydric phenolic compound is a divalent phenolic compound such as resorcinol, catechol, or hydroquinone. (4) The polymerization method according to claim 1 or 2, wherein the polyhydric phenolic compound is a trivalent phenolic compound such as pyrogallol, hydroxyhydroquinone, or phloroglucin. (5) The polymerization method according to claim 1 or 2, wherein the oxystyrene polymer is an o-, m-, or p-oxystyrene polymer.