JPS6059247B2 - Manufacturing method of vinyl chloride polymer - Google Patents

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 monomers when vinyl chloride is polymerized in an aqueous medium or in bulk. There are things.

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 walls of the polymerization vessel, stirring blades, baffle plates, and Film-like or lump-like scale tends to adhere to parts that come into contact with monomers, such as temperature detection tubes, and as a result, the heat of the polymerization reaction gets mixed into the product, which causes fish eyes and deteriorates the quality of the product. Such problems arise.

Therefore, it is customary to clean the inside of the polymerization reactor after every polymerization, but this requires a great deal of effort and time, which reduces the operating rate of the polymerization reactor, and also damages the inner walls of the polymerization reactor due to scale cutting. Such disadvantages may occur, such as damage to other equipment. Therefore, as a result of intensive study to develop a method for producing a vinyl chloride polymer that has improved ability to prevent scale from adhering to the inside of a polymerization reactor, the inventors of the present invention have discovered that vinyl chloride monomers or vinyl chloride monomers and When polymerizing a mixture of monomers that can be copolymerized with a monomer in an aqueous medium or in bulk, a reaction product of a phenol compound and an oily or waxy cyclopentadiene polymer is applied in advance to the inside of the polymerization reactor. The present invention was completed by discovering a method that achieves the intended purpose.

The oily or waxy cyclopentadiene polymer used as a raw material for the scale adhesion inhibitor in the present invention is prepared by adding a cyclopentadiene monomer or It can be obtained by a known method such as thermal polymerization of a mixture of a monomer and a comonomer (for example, JP-A-53-98383) or cationic polymerization.

Cyclopentadiene monomers include cyclopentadiene, lower alkyl-substituted cyclopentadiene such as methyl-substituted and ethyl-substituted cyclopentadiene, and lower Diels-Alder adducts thereof such as dimers, trimers, and codimers, and their selected from a mixture. Comonomers include monoolefins such as ethylene, propylene, butene, pentene, styrene, and α-methylstyrene, conjugated dienes such as 1,3-butadiene, isoprene, and 1,3-pentadiene, vinyl acetate, and vinyl propionate. , acrylic esters, methacrylic esters, acrylonitrile, acrolein, vinyl monomers having polar groups such as allyl alcohol, phenols such as phenol, cresol, oxystyrene, and the like. The oily polymer usually has a viscosity at 25°C of 100 to 50,000 centipoise, preferably 300 to 30,000 centipoise, and the waxy polymer has a melting point of 140°C or lower, preferably 100°C or lower. It is not preferable to use a resinous polymer instead of this polymer because it has poor reactivity with the phenol compound. The phenolic compound which is the other raw material for the anti-scaling agent in the present invention includes monohydric phenols such as phenol, cresol, p-chlorophenol, p-bromophenol, tert-butylphenol, octylphenol, xylenol, and bisphenol A1. Bisphenol F1
Resorcinol, hydroquinone, catechol, dioxytoluene, orcine, toluhydro. Dihydric phenols such as quinone, pyrochlore, hydroxyhydroquinone,
Examples include trihydric phenols such as phloroglucin.

When polyhydric phenol is used, the scale prevention effect is particularly remarkable, and this is thought to be due to the difference in the J radical inhibition effect or hydrophilic effect depending on the number of hydroxyl groups. The reaction product of a cyclopentadiene polymer and a phenol compound is produced by combining both in the presence of an acidic catalyst.
It is obtained by carrying out an alkylene reaction at 0 to 200°C for 5 minutes to 1 hour.

The acidic catalysts used here include hydrochloric acid, sulfuric acid, balatoluenesulfonic acid, aluminum chloride, ferric chloride,
Various organic and inorganic acids such as stannous chloride, boron trifluoride, and boron tribromide are exemplified, and among them, valatoluenesulfonic acid is preferred. The ratio of the phenol compound to the cyclopentadiene polymer is usually 10 parts by weight of the phenol compound to 5 to 20 parts by weight of the cyclopentadiene polymer.
0 parts by weight, preferably in the range of 50 to 15 parts by weight. If the usage ratio is outside this range, the scale adhesion prevention effect will decrease. The reaction product of both depends on the raw materials, but when monohydric phenol is used, the softening point is 40 to 80°C.
When polyhydric phenol is used, it is generally a resinous material at a temperature of 50 to 120°C.

The above reaction product may be applied as it is to the required location inside the polymerization reactor, but it is usually dissolved in an aqueous alkaline solution or an organic solvent such as methanol or acetone, and the solution is sprayed or brushed onto the polymerization reactor. It is applied inside the container.

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 coating, and it can be easily washed with water or inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid, carbonic acid, etc.
Alternatively, after washing with acidic water prepared with an organic carboxylic acid such as formic acid, acetic acid, or oxalic acid, the polymerization medium can be subsequently charged into the polymerization reactor to initiate polymerization, which is particularly preferred. The solid content concentration of the coating solution is 0.1 to 1% by weight.
It is preferable for the work to be within the range of . Although the coating amount is not particularly limited, if the solid content is 0.001 f1/d or more, sufficient scale adhesion prevention can be achieved. The upper limit of the application amount is, for example, 1y unless there is a particular negative effect.
It may be set to /A or above. 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 process according to the invention can be applied to polymerizations in aqueous media, ie suspension polymerization, emulsion polymerization, milk suspension polymerization, and also to bulk polymerizations. 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, acrylic acid alkyl esters 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 the polymerization initiator include organic peroxides such as lauroyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and t-butyl peroxypivalate, and α,α″-azobisisobutyronitrile. Examples include azo compounds such as, or inorganic peroxides such as ammonium persulfate and potassium persulfate. Examples of suspending agents include polyvinyl alcohol, partially saponified polyvinyl acetate, cellulose derivatives such as methylcellulose, polyvinylpyrrolidone, Examples include synthetic polymeric substances such as maleic anhydride monovinyl acetate copolymer, and natural polymeric substances such as starch and gelatin. Examples of emulsifiers include anionic emulsifiers such as sodium alkylbenzenesulfonate and sodium lauryl sulfate. Examples include nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene sorbitan fatty acid partial ester, etc.A molecular weight regulator can also be used if necessary.The above-mentioned polymerization initiators, 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 may be added in portions during polymerization. The process is carried out under stirring at a temperature of °C.The method of the present invention can effectively prevent scale adhesion and maintain this effect for a long time. It is extremely useful because it does not have any adverse effects such as deterioration of particle size distribution, color tone, and shape.

The present invention will be specifically explained below using examples.

Note that the number of parts and percentages in each example are based on weight.
Reference Example 1 100 parts of pyrogallol was placed in a four-ring flask, and an oily cyclopentadiene polymer (50% dicyclopentadiene and 1,3-
1 (4) parts of thermal copolymer with 50% pentadiene) and 0.2 parts of valatoluenesulfonic acid were charged, and reaction was carried out at 160'C for 2 hours under a nitrogen atmosphere.

After the reaction was completed, it was cooled to 100°C or less, and then 40% of water was added, washed with water, and the supernatant liquid was separated, followed by 75wRHy.
Dehydration and concentration were performed under reduced pressure, 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 107°C was obtained. This product was soluble in aqueous alkaline solutions and polar solvents such as methanol and acetone. Reference Example 2 A four-hole flask was charged with 10 parts of resorcinol, 70 parts of the same oily cyclopentadiene polymer used in Reference Example 1, and 02 parts of valatoluene sulfonic acid, and a reaction was carried out in the same manner as in Reference Example 1. A deep purple reaction product was obtained at 101°C.

This product 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 phenol was used instead of pyrogallol, and a deep purple reaction product with a softening point of 40°C was obtained.

This product was sparingly soluble in aqueous alkaline solutions and methanol, but soluble in acetone and toluene. Reference Example 4 A reaction was carried out in the same manner as in Reference Example 1, except that an oily cyclopentadiene homopolymer having a viscosity of 8000 centipoise at 25°C was used in place of the cyclopentadiene polymer used in Reference Example 1, and softening occurred. A deep purple reaction product with a temperature of 110°C was obtained.

This product was soluble in alkaline aqueous solution, methanol, and acetone. Reference Example 5 Reference Example 1 without using oily cyclopentadiene polymer
When the same reaction was carried out, a dark 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 1% by weight aqueous solution of caustic soda to prepare a coating solution with a solid content concentration of 3% by weight.

Next, apply the above coating solution to the inner wall of a stainless steel polymerization vessel with an internal volume of 1 d and the area in contact with the monomer using a sprayer so that the coating amount is 0.5 y/Rrl (in terms of solid content, the same applies hereinafter). After spraying, the coated surface was washed with deionized water.
Next, 400k9 of deionized water, 180y12-ethylhexyl peroxycarbonate 30y1, 60y tert-butyl peroxypivalate were charged into the polymerization vessel, and after degassing, vinyl chloride monomer 20y
0k9 was charged and polymerization was carried out at Seki°C for 12 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 k9/Clt, 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, and 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, a scale of 340 y/d was deposited inside the polymerization vessel.

Comparative Example 2 A 2% toluene solution of the cyclopentadiene polymer used in Reference Example 1 was applied in a polymerization vessel to a coating amount of 0.5 y/distance, and after air drying, polymerization was carried out in the same manner as in Example 1. When the scale adhesion was observed after polymerization, it was found that 310
It was found that scale of y/d was attached, and this polymer alone had almost no effect on preventing scale attachment.

Comparative Example 3 The reaction product obtained in Reference Example 5 was dissolved in water to prepare a coating solution having a solid content concentration of 2% by weight.

Subsequently, it was applied in the same manner as in Example 1, washed with water, and then polymerized.
When observing the state of scale adhesion after polymerization, it was found that 200y
/Cd scale was attached. It was found that a viscous reaction product prepared using only a phenol compound as a raw material 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 attached to 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,
A coating liquid having a solid content concentration of 2% by weight was prepared.

Subsequently, it was applied in the same manner as in Example 1, washed with water, and then polymerized.
When observing the state of scale adhesion after polymerization, it was found that 150y
/A scale has adhered. Although the reaction product prepared using monohydric phenol had less scale adhesion prevention effect than the case using polyhydric phenol, 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.

Subsequently, the coating solution was sprayed with a sprayer to the inner wall of a stainless steel polymerization vessel with an internal volume of 1 d and other parts that would come into contact with the monomer to a coating amount of 1 y/i, and the coated surface was further washed with deionized water. . After that, add 400k9 of deionized water to the polymerization vessel.
Partially saponified polyvinyl acetate 250y1 Hydroxymethylpropyl cellulose 150y1 Tertiary butyl baroxypivalet 00fI was charged, and after degassing, vinyl chloride monomer 180k9 and vinyl acetate monomer 20k9 were charged and polymerized at 60°C for one hour. I went to

After the polymerization was completed, the inside of the polymerization vessel was washed with a weak water pressure of 5 to 10 k9/Clt, and the state of scale adhesion was observed.
No scale was attached at all. Furthermore, 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 400 y/d was deposited inside the polymerization vessel.

Example 6 The same coating liquid used in Example 5 was sprayed onto the inner wall of a stainless steel polymerization vessel with an internal volume of 1 d and the parts that would come into contact with other monomers, so that the coating amount was 1.5 y/d. Then, the coated surface was further washed with deionized water.

After that, 400k9 of deionized water, 1k9 of lauryl sulfate sorter, and 260y of potassium persulfate were charged into the polymerization vessel, and after degassing, 200kg of vinyl chloride monomer was charged and heated at 55°C for 10
Time polymerization was carried out. After polymerization is completed, the interior of the polymerization vessel is
It was washed with water at a weak water pressure of 10 kg/Crl and the state of scale adhesion was observed, but no scale was observed at all. Comparative Example 6 When the same experiment as in Example 6 was conducted without using the coating liquid, a scale of 260 y/d was deposited inside the polymerization vessel.

Example 7 The same coating liquid 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 monomer using a sprayer to a coating amount of 1.5 d/day. Furthermore, the coated surface was washed with deionized water and dried.

After that, 5k9 of vinyl chloride monomer containing 0.0% azobisisobutyronitrile was added to the autoclave.
Polymerization was carried out at 5°C for 1 hour. After the polymerization was completed, the state of 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/d was observed in the polymerization vessel.

Claims (1)

[Claims] 1. When a vinyl chloride monomer or a mixture of a vinyl chloride monomer and a monomer copolymerizable therewith is polymerized in an aqueous medium or in bulk, a phenolic compound and an oily or waxy A method for producing a vinyl chloride polymer, which comprises applying a reaction product of the above with a cyclopentadiene polymer to the inside of a polymerization reactor in advance. 2. The reaction product of a phenol compound and an oily or waxy cyclopentadiene polymer is applied to the inside of a polymerization reactor as an aqueous alkaline solution or an organic solvent solution of the reaction product, as described in claim 1. manufacturing method.