JPS6071614A - Production of vinyl chloride based polymer - Google Patents

Abstract

PURPOSE:To prevent the deposition of polymer scales, by coating the interior of a reactor with a reaction product of a phenolic compound with a cyclopentadiene based monomer in polymerizing a vinyl chloride monomer, etc. in an aqueous medium, etc. CONSTITUTION:A cyclopentadiene based monomer is reacted with a phenolic compound in the presence of an acidic catalyst, e.g. hydrochloric acid. The interior of a polymerizer is then coated with the resultant reaction product, and vinyl chloride monomer is polymerized or copolymerized with a monomer copolymerizable therewith, e.g. vinyl acetate, in the presence of a polymerization initiator, e.g. lauroyl peroxide, in an aqueous medium by adding a suspending agent, e.g. polyvinyl alcohol, or an emulsifying agent, e.g. a sodium alkylbenzenesulfonate, thereto to give the aimed polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing polymer scale from adhering to the inner wall of a polymerization vessel and other parts that come into contact with polymers when vinyl chloride is polymerized in an aqueous medium or in bulk. It is something.

When vinyl chloride monomer or a mixture of vinyl chloride monomer and other monomers copolymerizable with vinyl chloride monomer is polymerized in an aqueous medium or in bulk, the inner wall of the polymerization vessel, the stirring blade, the baffle plate, and the temperature Film-like or lump-like scales tend to adhere to parts such as detector tubes that come in contact with monomers, which reduces the ability to remove polymerization reaction heat, and scales peeled off during polymerization can get mixed into the product, which can cause fisheye. Therefore, it is customary to clean the inside of the polymerization reactor after each polymerization, but this requires a great deal of effort and time. In addition to reducing the operating rate of the reactor, there are disadvantages such as damage to equipment such as the inner wall of the polymerization reactor due to scale cutting.

Therefore, the present inventors have developed a method for producing a vinyl chloride polymer that has improved ability to prevent scale from adhering to the inside of a polymerization reactor. When polymerizing a mixture of monomers that can be copolymerized with a monomer in an aqueous medium in bulk or in bulk, there is a method in which a reaction product of a phenol compound and a cyclopentadiene monomer is applied in advance to the inside of a polymerization reactor. The inventors have discovered that the intended purpose can be achieved and have completed the present invention.

The cyclopentadiene monomer used as a raw material for the scale adhesion prevention agent in the present invention includes cyclopentadiene, lower alkyl-substituted cyclopentadiene such as methyl-substituted and ethyl-substituted cyclopentadiene, and dimers and dimers thereof. selected from low-order Diels-Alder adducts such as symbipods and mixtures thereof.

The phenol compound which is the other U ingredient of the scale adhesion inhibitor in the present invention includes phenol, cresol% p-chlorophenol, p-bromophenol, tertiary-butylphenol, octylphenol, xylenol and other monohydric phenols, bisphenol, etc. A, Bisphenol F Examples include dihydric phenols such as lusorcinol, hydroquinone, categol, dioxytoluene, orcine, and toluhitosequinone, and trihydric phenols such as pyrogallol, hydroxyhydroquinone, and phloroglucin. When polyhydric phenol is used, the scale prevention effect is particularly remarkable, but this is thought to be due to the difference in radical inhibition effect or hydrophilic effect depending on the number of hydroxyl groups.

The reaction product of a cyclopentadiene monomer and a phenol compound is produced by combining both in the presence of an acidic catalyst to a concentration of 120 to 200
``React at C for 5 minutes to 10 hours.
Therefore, it is obtained. The acidic catalyst used here is
Hydrochloric acid, sulfuric acid, para-toluenesulfonic acid, aluminum chloride, ferric chloride.

Various organic and inorganic acids such as stannous chloride, boron trifluoride, and boron tribromide are exemplified, and para-toluenesulfonic acid is particularly preferred.

The ratio of the phenol compound to the cyclopentadiene monomer is usually 5 to 100 parts by weight, preferably 40 to 80 parts by weight, per 100 parts by weight of the phenol compound. If the usage ratio is outside this range, the scale adhesion prevention effect will decrease.

Although the reaction products of both products depend on the raw materials, they are generally resin-like substances having a softening point of 30 to 50°C when a -hydric phenol is used and 60 to 100°C when a polyhydric phenol is used.

The above-mentioned reaction product may be applied as it is to the required location inside the polymerization reactor, but usually it is dissolved in an aqueous alkali solution or an organic solvent such as methanol or acetone, and the solution is polymerized by spraying or brushing. Applied inside the reactor.

When an alkaline aqueous solution is used as the solution, there is no need to heat and dry the surface in the polymerization reactor after application (simple water washing or inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid, carbonic acid, or formic acid or acetic acid). After washing with acidic water adjusted with an organic carboxylic acid such as oxalic acid, the polymerization medium can be subsequently charged into the polymerization reactor to start the polymerization, which is particularly preferred.

It is preferable for the solid content concentration of the coating solution to be in the range of 0.1 to 10% by weight. Although the coating amount is not particularly limited, if the solid content is o, oosE/i or more, sufficient scale adhesion prevention can be achieved. The upper limit of the application amount is, for example, 11/rt, unless there are any particular adverse effects. The above may be used. Coating may be carried out after each polymerization reaction, but even if the polymerization reaction is simply washed after the completion of the polymerization reaction, the polymerization reaction can be carried out several times or more without causing scale adhesion.

The method of the present invention involves polymerization in an aqueous medium, i.e. suspension polymerization,
It can be applied to emulsion polymerization, milk suspension polymerization, and bulk polymerization.

Examples of monomers that can be copolymerized with the vinyl chloride monomer in the method of the present invention include vinyl esters such as vinyl acetate, alkyl vinyl ethers such as cetyl vinyl ether, α-monoolefins such as ethylene or propylene, and vinylidene chloride. Examples include vinylidene halides and alkyl acrylates such as methyl acrylate and methyl methacrylate.

Furthermore, the polymerization agents used in the present invention, such as a polymerization initiator, suspending agent, or emulsifier, are those used in ordinary polymerization or bulk polymerization of vinyl chloride in an aqueous medium. Examples of polymerization initiators include lauroyl peroxide,
Organic peroxides such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, t-butyl peroxyhybarate, α, α′-
Examples include azo compounds such as azobisisobutyronitrile, and inorganic peroxides such as ammonium persulfate and potassium persulfate. Suspending agents include polyvinyl alcohol, partially saponified polyvinyl acetate, cellulose derivatives such as methylcellulose, polyvinylpyrrolidone, synthetic polymers such as maleic anhydride-vinyl acetate copolymers, and natural polymers such as starch and gelatin. Examples include molecular substances. Examples of emulsifiers include anionic emulsifiers such as alkylbenzene sulfo/acid soda and lauryl sulfate, and nonionic emulsifiers such as polyoxyethylene alkyl ether and polyoxyethylene sorbitan fatty acid partial ester. Moreover, a molecular weight regulator can be used if necessary. The above-mentioned polymerization initiator, vinyl chloride and other monomers, suspending agents, emulsifiers, molecular weight regulators, etc. may be added to the polymerization system all at once at the start of polymerization, or they may be added in portions during polymerization. You can also do that. Polymerization is usually carried out at a temperature of 35-80''C with stirring.

Although the method of the present invention can effectively prevent scale adhesion and maintain its effect for a long time, it may also delay the polymerization rate or worsen the particle size distribution, color tone, fish eyes, etc. of the product. It is extremely useful as it does not have any negative effects such as causing irritation.

The present invention will be specifically explained below using examples. Note that the number of parts and coefficients on each side are based on weight.

Reference Example 1 A four-day flask was charged with 100 parts of pyrogallol, yso parts of dicyclopentadiene, and 0.2 parts of paratoluenesulfonic acid, and a reaction was carried out at 150° C. for 4 hours under a nitrogen atmosphere.

After the reaction was completed, it was cooled to 100°C or less, and then 400 parts of water was added, washed with water, and the supernatant liquid was separated, and then heated to 75 mH.
Dehydration and concentration were performed under reduced pressure of H, and the concentration was completed when the internal temperature reached 150°C. As a result, a deep purple reaction product with a softening point of 85°C was obtained. This product was soluble in aqueous alkaline solutions and polar solvents such as methanol and acetone.

Reference Example 2 A four-day flask was charged with 100 parts of resorcin, 60 parts of the same dicyclopentadiene used in Reference Example 1, and 0.2 parts of para-toluenesulfonic acid, and a reaction was carried out in the same manner as in Reference Example 1, resulting in softening. A deep purple reaction product with a temperature of 76°C was obtained. This product is.

It was soluble in aqueous alkaline solutions and polar solvents such as methanol and acetone.

Reference Example 3 A reaction was carried out in the same manner as in Reference Example 1 except that pyrogallol 1 was modified to phenol, and a deep purple reaction product with a softening point of 31°C was obtained. This product was sparingly soluble in aqueous alkaline solutions and methanol, but soluble in aceto/toluene.

Reference Example 4 A reaction was carried out in the same manner as in Reference Example 1 except that cyclopentadiene was used in place of the dicyclopentadiene used in Reference Example 1. A deep purple reaction product with a softening point of 67°C was obtained. It was done. This product was soluble in alkaline aqueous solution, methanol, and acetone.

Reference Example 5 When the same reaction as in Reference Example 1 was carried out without using the cyclobencdiene monomer, a deep purple viscous reaction product was obtained. This product was water soluble.

Example 1 The reaction product obtained in Reference Example 1 was dissolved in a 54% aqueous sodium hydroxide solution to prepare a coating solution having a solid content concentration of 3% by weight. Subsequently, the inner wall of a stainless steel polymerization vessel with an internal volume of 1-1 and the portion in contact with the monomer were sprayed with o and s 9 with a sprayer.
The above coating solution was sprayed to a coating amount of /rl (in terms of solid content, the same applies hereinafter), and the coated surface was further washed with deionized water.

Next, 400 g of deionized water, 180 g% of partially saponified polyvinyl acetate (2-ethylhexyl peroxydicarbonate, 309 tertiary butyl peroxypivale) 6Cl were charged into the polymerization vessel, and after desilvering, vinyl chloride monomer was added. The polymerization was carried out at 58° C. for 12 hours after charging 200 hours. After the polymerization was completed, the interior of the polymerization vessel was washed with water at a weak water pressure of 5 to 10 kg/crl, and the state of scale adhesion was observed, but no scale was found to have adhered. Furthermore, no adverse effects such as delayed reaction, rough particle size of the product, deterioration of color tone, or increase in fish eyes occurred.

Comparative Example 1 When the same experiment as in Example 1 was conducted without using the coating liquid used in Example 1, 330 g/d of scale was deposited inside the polymerization vessel.

Comparative Example 2 The dicyclopentadiene used in Reference Example 1 was made into a 2-titoluene solution and applied in a polymerization vessel at a coating amount of o, sl/rrl, and after air drying, polymerization was carried out in the same manner as in Example 1.
After observing the scale adhesion after polymerization, it was found that 3001
A scale of 1/rl was deposited, and it was found that this polymer alone had almost no effect on preventing scale deposition.

Comparative Example 3 The reaction product obtained in Reference Example 5 was dissolved in water to prepare a coating liquid with a solid content concentration of 2% by weight. Subsequently, the coating was applied in the same manner as in Example 1, and polymerization was performed after washing with water. When the state of scale adhesion was observed after polymerization, scale of 2009/cd was observed. It was found that viscous reaction products prepared using only phenolic compounds as raw materials had little effect on preventing scale adhesion.

Example 2 An experiment similar to Example 1 was conducted using the reaction product obtained in Reference Example 2 instead of the reaction product obtained in Reference Example 1, and it was found that no scale was deposited inside the polymerization vessel. Similarly to Example 1, no reaction delay or adverse effect on product quality was observed.

Example 3 The reaction product obtained in Reference Example 3 was dissolved in acetone,
1. A coating solution with a solid content concentration of 2% by weight was prepared.
It was coated in the same manner as in Example 1, washed with water, and then polymerized. After the polymerization, the state of scale adhesion was observed, and 120 g/m' of scale was observed. Although the reaction product prepared using -hydric phenol had less scale adhesion prevention effect than the case where polyhydric phenol was used, the effect was observed.

Example 4 An experiment similar to Example 1 was conducted except that the reaction product obtained in Reference Example 4 was used instead of the reaction product obtained in Reference Example 1. No adhesion was observed.

Example 5 The resinous compound obtained in Reference Example 1 was dissolved in methanol to prepare a coating solution having a solid content concentration of 2% by weight.

Next, the internal volume ITr? The coating liquid was sprayed with a sprayer to the inner wall of the stainless steel polymerization vessel and other parts that would come in contact with the polymer to a coating amount of 197 m, and the coated surface was further washed with deionized water.

After that, the polymerization vessel was filled with 400 kl of deionized water, 25 C1 of partially saponified polyvinyl acetate, and 150.9 kg of hydroxymethylpropyl cellulose. 100 g of tert-butyl peroxyvivalate was charged, and after degassing, 180 g of vinyl chloride monomer and 20 g of vinyl acetate monomer were charged, and polymerization was carried out at 60°C for 15 hours. After the polymerization was completed, the inside of the polymerization vessel was washed with a weak water pressure of 5~H)'kg/d, and the state of scale adhesion was observed, but no scale was found to be attached at all.

In addition, no adverse effects such as delayed reaction, rough particle size, or deterioration of color tone occurred.

Comparative Example 5 When the same experiment as in Example 5 was conducted without using the coating liquid used in Example 5, a scale of 3809/- was deposited inside the polymerization vessel.

Example 6 The same coating solution used in Example 5 was applied to the inner wall of a stainless steel polymerization vessel with an internal volume of 1-sg/m' in an amount of 1-s g/m' using a sprayer to the parts that would come into contact with other monomers. The coated surface was then washed with deionized water. Thereafter, 400 kg of deionized water, 1 kg of sodium lauryl sulfate, and potassium persulfate 2609 were charged into a polymerization vessel, and after degassing, 9 was charged to the polymerized vinyl monomer 200, and polymerization was carried out at 55° C. for 10 hours. After the polymerization is completed, the inside of the polymerization vessel is heated for 5 to 10 minutes.
After washing with water at a weak water pressure of 9/cIl, the state of scale adhesion was observed, but no scale was observed.

Comparative Example 6 When the same experiment as in Example 6 was conducted without using the coating liquid, 2709/yl scale was deposited inside the polymerization vessel.

Example 7 The same coating solution used in Example 5 was sprayed on the inner wall of a stainless steel autoclave with an internal volume of 101 mm and other parts that come into contact with the mass body, using a sprayer, to a coating amount of 1.597 m, and then deionized water was added. The coated surface was washed and dried. Thereafter, 5 kg of vinyl chloride monomer containing 0.023 tt% azobisisobutyronitrile was charged into an autoclave and polymerized at 55°C for 10 hours. After the polymerization was completed, the scale adhesion inside the autoclave was observed, but no scale was observed at all.

Comparative Example 7 When the same experiment as in Example 7 was conducted without using the coating liquid, a scale of 4909/rl was deposited inside the polymerization vessel.

Patent applicant: Zeon Corporation

Claims (2)

[Claims] (1) When polymerizing vinyl chloride monomer or a mixture of vinyl chloride monomer and monomers copolymerizable with it in an aqueous medium or in bulk, a phenol compound and a cyclopentadiene monomer 1. A method for producing a vinyl chloride polymer, which comprises applying the reaction product to the inside of a polymerization reactor in advance. (2) The reaction product of the phenol compound and the cyclopentadiene monomer is applied to the inside of the polymerization reactor as an alkaline aqueous solution or an organic solution of the reaction product, as described in claim (1). Manufacturing method 0