JP2001354705A - Method for manufacturing polymer from monomer having ethylenic double bond - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a polymer from a monomer having an ethylenic double bond wherein the productivity is enhanced by shortening the time for forming a coating of a scale preventing agent to the inner of a reactor the polymer scale adhesion preventing effect is improved, contamination by foreign materials is reduced, resistance to fish eye generation and initial discoloring of the molded article is improved, and qualities of the polymer and processed articles thereof are improved. SOLUTION: When polymerization is performed in a polymerizer using a monomer having an ethylenically double bond, a coating composed of a first layer and a second layer is formed on the internal wall, etc., of the polymerizer. The first layer is formed by applying a first coating liquid using steam as a carrier, the first coating liquid comprising a condensate (A) obtained by carrying out a condensation reaction of an aldehyde compound and an aromatic hydroxy compound in the presence of a nitrite and/or a reducing sugar. The second layer is formed by applying a second coating liquid using steam as a carrier to the surface of the first layer, the second coating liquid comprising at least one (B) selected from the group consisting of a water-soluble polymer, an inorganic colloid, an inorganic salt and an acid. The polymerization is carried out in this polymerizer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing a polymer by polymerizing a monomer having an ethylenic double bond in a polymerization vessel. The present invention relates to a method for producing a polymer which can prevent the production of a polymer having good quality.

[0002]

2. Description of the Related Art In a method for producing a polymer by polymerizing a monomer in a polymerization vessel, there is a known problem that the polymer adheres as a scale to the inner wall surface of the polymerization vessel. When the polymer scale adheres to the inner wall of the polymerization vessel, the yield of the polymer decreases, the cooling capacity in the polymerization vessel decreases, and the adhered polymer scale peels off and mixes into the polymer product, resulting in poor product quality. This leads to disadvantages such as a large amount of labor and time required for removing the polymer scale. Moreover,
Because the polymer scale contains unreacted monomers, workers may be exposed to it and cause physical injury.

[0003] Therefore, in the polymerization of a monomer having an ethylenic double bond, for example, the polymer is attached to the inner wall of the polymerization vessel and a stirrer in order to prevent adhesion of the polymer scale to the inner wall of the polymerization vessel. Various methods are known for forming a coating film by applying a scale adhesion inhibitor (hereinafter referred to as a scale inhibitor) in a one-step coating operation (hereinafter referred to as a one-component coating method). Specifically, for example, polar organic compounds such as amine compounds, quinone compounds and aldehyde compounds, or dyes and pigments (Japanese Patent Publication No.
-30343, JP-B-45-30835); those obtained by treating a polar organic compound or dye with a metal salt (JP-B-52-24953); a mixture of an electron-donating compound and an electron-accepting compound (JP-B-53)
-28347); Condensation reaction product of 1-naphthol with formaldehyde (JP-A-57-164107); Condensation reaction product of phenol compound with formaldehyde (JP-A-57-19)
2413); Polyaromatic amines (JP-B-59-16561); Self-condensation products of polyhydric phenols and self-condensation products of polyhydric naphthols (JP-A-54-7487); Condensation reaction between ketone resin and phenol compound Product (JP-A-62-236804); Condensation reaction product of aromatic amine and aromatic nitro compound and base product thereof (JP-B-60-30681); (JP-A-61-7309).

[0004] In the polymerized scale adhesion-preventing coating film (hereinafter referred to as scale-preventing coating film) obtained by this one-component coating method, scale easily adheres to the vicinity of the gas-liquid interface in the polymerization vessel during polymerization, Depending on the composition of the reaction solution, the scale may adhere to the entire wall surface.To prevent this, the coating solution of the scale inhibitor should be added to the anionic polymer compound, amphoteric polymer compound, cationic polymer compound, Water-soluble polymer compounds such as group-containing polymer compounds; inorganic colloids; substances having no affinity for monomers (hereinafter referred to as scale prevention assistants) such as inorganic salts such as alkali metal salts are mixed. It is also known to do.
These one-component coating methods are effective in preventing polymer scale adhesion in polymerization of a monomer having an ethylenic double bond in a polymerization vessel.

In the one-component coating method, when the effect of preventing the adhesion of the polymer scale cannot be sufficiently obtained, (a) a coating solution containing the above-described scale inhibitor is applied to form a first layer; Further, a coating film is formed by applying two types of coating solutions in two steps of forming a second layer by applying a coating solution containing the above-mentioned polymer scale adhesion preventing auxiliary (b). (Hereinafter referred to as a two-liquid two-step coating method)
03-74404, JP-A-02-80403, JP-A-02-80402, JP-A-02-80401, and JP-A-02-47102) have been proposed.

[0006] Both the method for preventing adhesion of the polymer scale by the one-liquid coating described above and the method for preventing the adhesion of the polymer scale by the two-liquid two-stage coating are applied in terms of productivity such as workability. Spray coating methods are commonly used.

[0007] The formation of the coating film in the one-part coating method of the scale inhibitor by the spray coating method is as follows: Step 1: The coating solution containing the scale inhibitor is applied to the inner wall surface of the polymerization vessel and other monomers by the spray coating method. Step 1: drying the coated surface to form a dry coating film; Step 3: washing the formed coating surface to remove excess coating liquid; 3 is provided.
In addition, the two-liquid two-stage coating method including the application of the scale inhibitor and the application of the scale-preventing auxiliary agent by the spray coating method is similar to the above-described Step 1 in the second-stage coating.
3 is performed.

When the above-mentioned spray coating method is used, the surface of the baffle and the stirring blade facing the inner wall surface of the polymerization vessel has a blind spot when viewed from the spray nozzle. Since the coating liquid hardly reaches the surface of the shaded or hidden portion when viewed from such a spray nozzle, the scale inhibitor cannot be applied in the same manner as other non-shaded surfaces. Therefore, it is difficult to form a uniform coating film on a shaded surface and a non-shaded surface. Further, in order to prevent the adhesion of scale on the surface to be shaded, if an effective amount of a coating film is to be formed, a coating solution containing a larger amount of a scale inhibitor than other surfaces must be used. Unnecessary excesses of antiscalant will be applied to non-shading surfaces. Therefore, the coating film thus formed had coating unevenness, and the coating film was partially thicker than necessary.

Further, the formation of a scale-preventing coating film using the spray coating method has the following problems. A coating of the scale inhibitor is usually formed before each polymerization batch. Since the scale inhibitor is generally colored, when the number of repetitions of the polymerization batch is increased, the scale inhibitor is repeatedly applied, and as a result, a thick part of the coating film may be generated. Such a thick portion of the coating film is peeled and taken into the reaction mixture, or a scale inhibitor is applied on the polymer scale already formed on the inner wall of the polymerization vessel and peeled off together with a part of the scale. There is a disadvantage that it is mixed into the obtained polymer product and causes colored foreign matters or fish eyes in the molded product, and the quality of the product is deteriorated such as increasing the initial coloring of the molded product. As mentioned above, the polymer scale adhesion prevention effect on the hidden or shaded surface in the polymerization vessel which is blind spot from the spray nozzle is much larger than the other surface. It is not enough to apply the inhibitor. The spray coating method requires a drying step of drying the coated surface after coating, and it takes a long time to form a coating film of the scale inhibitor. Therefore, from the viewpoint of improving productivity, it is desired to reduce the time required for forming the coating film.

As a method for solving the drawbacks of the above spray coating method, there has been proposed a method of applying a coating solution of a scale inhibitor using steam as a carrier (hereinafter referred to as steam coating) (Japanese Patent Publication No. 01-5044). . As the coating liquid in this case, a coating liquid containing only the scale preventing agent or a coating liquid obtained by adding the above-described scale preventing auxiliary to the coating liquid is used.

This steam coating method has the following advantages. With a small amount of coating solution, the scale inhibitor required to effectively prevent the adhesion of scale can be formed as a thin uniform coating film. A small amount of coating solution used, a scale inhibitor required to prevent scale adhesion even in hidden or shaded areas in the polymerization vessel that are blind spots when viewed from the spray nozzle. Thus, the effect of preventing adhesion of polymer scale can be obtained even in these portions. The drying step in the coating film forming step becomes unnecessary, and the time required for forming a coating film such as a scale inhibitor is reduced.

By the way, in the steam coating method, a coating solution is mixed with steam, and the coating solution is applied to the inner wall surface of a polymerization vessel or the like while being carried by the steam. Therefore, the concentration of the scale inhibitor in the coating liquid is set in consideration of dilution with water vapor. Usually, the concentration of the scale inhibitor in the coating solution is 4 to 40 times that for the steam application than for the spray application. However, the amount of the scale inhibitor required for the steam application is almost the same as that for the spray application.

Although the steam coating method has the above advantages, it has the following problems. Although water vapor coating enables uniform coating in the polymerization vessel, the effect of preventing scale near the gas-liquid interface in the polymerization vessel is insufficient. Because the effect of preventing scale adhesion near the gas-liquid interface in the polymerization vessel is insufficient, polymer scale deposits grow near the gas-liquid interface when the number of repetitions of the polymerization batch increases, and the deposited scale peels off during polymerization. And may be mixed into the polymer product to cause fish eyes. In addition, when the number of repetitions of the polymerization batch increases, the scale inhibitor is repeatedly applied, so that the scale inhibitor layer becomes gradually thicker, and this layer is partially peeled and mixed into the polymer product to remove colored foreign matter. This causes a problem that the anti-initial coloring property of the polymer product is reduced (in particular, the brightness index is reduced).

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the time required for forming a coating film such as a scale inhibitor, thereby improving the productivity and improving the effect of preventing the adhesion of polymer scale. Reduce the mixing of colored foreign substances into products,
An object of the present invention is to provide a method for producing a polymer by polymerizing a monomer having an ethylenic double bond, which can enhance the fisheye and anti-initial coloring properties of a molded article and improve the quality of the polymer and its processed product.

[0015]

An object of the present invention is to provide a method for producing a polymer, comprising polymerizing a monomer having an ethylenic double bond in a polymerization vessel, wherein the polymerization vessel has an inner wall surface and Having a polymer scale anti-adhesion coating on the other surface with which the monomer contacts during polymerization; wherein the coating is a first layer formed on the inner wall surface and other surfaces And a second layer formed on the first layer, wherein the first layer is at least selected from the group consisting of nitrites and reducing sugars in a condensation reaction between an aldehyde compound and an aromatic hydroxy compound. The coating liquid containing the condensate (A) obtained by performing in the presence of one kind, is formed by coating using steam as a carrier, the second layer, the second layer of the first layer Above, water-soluble polymer compound, inorganic colloid It is formed by applying a second coating solution containing at least one polymer scale adhesion preventing auxiliary (B) selected from the group consisting of an inorganic salt and an acid by using steam as a carrier; This is achieved by a method for polymerizing a monomer having an ethylenic double bond, which is characterized in that:

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The scale-inhibiting coating film used in the method of the present invention comprises a first layer formed on a surface such as an inner wall surface of a polymerization vessel and a second layer formed thereon.

[First Layer of Coating Film] The condensate (A) used in the coating solution for forming the first layer is a group consisting of a nitrite and a reducing sugar, which is used for the condensation reaction between an aldehyde compound and an aromatic hydroxy compound. Obtained in the presence of at least one member selected from the group consisting of: The details will be described below. <Aldehyde compound> Examples of the aldehyde compound include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, acrolein, crotonaldehyde, benzaldehyde, furfural, phenylacetaldehyde, 3-phenylpropionaldehyde, and 2-phenylpropionaldehyde. Acetaldehyde is industrially and economically advantageous.

<Aromatic hydroxy compound> Examples of the aromatic hydroxy compound include dihydroxybiphenyl compounds, naphthol compounds, phenol compounds, tannins and 2,3-dihydroxynaphthalene.
Monomer compounds and the like.

Examples of the dihydroxybiphenyl compound include 2,2'-dihydroxybiphenyl and 2,2'-
Dihydroxy-5,5'-dimethylbiphenyl, 2,
2'-dihydroxy-4,4 ', 5,5'-tetramethylbiphenyl, 2,2'-dihydroxy-5,5'-dichlorobiphenyl, 2,2'-dihydroxy-5,5'
-Dichlorohexylbiphenyl, 2,2'-dihydroxy-5,5'-di-tert-butylbiphenyl, and the like. Of these, 2,2'-dihydroxybiphenyl is particularly suitable industrially.

Examples of the naphthol compound include 1-naphthol, 2-naphthol, 1,3-dihydroxy-naphthalene, 1,5-dihydroxynaphthalene and 1,7-naphthol.
-Dihydroxynaphthalene, 6-hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, 1-hydroxy-8-naphthoic acid and the like.

Examples of the phenolic compounds include phenol, cresol, pyrogallol, hydroxyhydroquinone, resorcin, catechol, hydroquinone, bisphenol A, hydroxybenzoic acid, dihydroxybenzoic acid, 2-hydroxy-5-methoxybenzoic acid, salicylic acid and the like. No.

Examples of tannins include tannic acid, quintuple tannin, gallic tannin, smack tannin, quebracho tannin, and persimmon tannin.

Examples of the dimer compound of 2,3-dihydroxynaphthalene include 2,3,2 ', 3'-tetrahydroxybinaphthyl and the like.

<Nitrite> Examples of nitrite include zinc nitrite, ammonium nitrite, potassium nitrite, calcium nitrite, silver nitrite, cobalt potassium nitrite, sodium cobalt nitrite, strontium nitrite, cesium nitrite, and cesium nitrite. Examples include cerium nitrate, cupric nitrite, sodium nitrite, nickel nitrite, barium nitrite, magnesium nitrite, lithium nitrite, rubidium nitrite and the like. These can be used alone or in combination of two or more.

<Reducing Sugars> Reducing sugars are sugars having a free aldehyde group or ketone group and exhibiting reducing properties. For example, maltose, lactose, glucose (glucose) and the like can be mentioned. These can be used alone or in combination of two or more.

The condensate of the aldehyde compound and the aromatic hydroxy compound is prepared by mixing these reaction components in a suitable medium in the presence of a catalyst, usually at room temperature to 200 ° C. for 2 to 100 hours.
It is preferably produced by reacting at 30 to 150 ° C. for 3 to 30 hours. Further, each of the aldehyde compound and the aromatic hydroxy compound may be used alone or in combination of two or more. The nitrite and / or reducing saccharide is preferably added to the reaction mixture between immediately before the start of the condensation reaction and the middle stage of the reaction. Here, immediately before the start of condensation is before the catalyst is added and / or before heating is started, and the middle stage of the reaction is a state in which the reaction is not completed and unreacted substances remain.

As the medium for carrying out the above condensation reaction, for example, water or organic solvents such as alcohols, ketones and esters can be mentioned. For example, alcohols such as methanol, ethanol and propanol, acetone, methyl ethyl ketone and the like can be mentioned. Ketones and esters such as methyl acetate and ethyl acetate. The pH of the medium for performing the above condensation reaction is usually in the range of 1 to 13, and the pH adjuster can be used without any particular limitation. The catalyst used in the condensation reaction, such as sulfuric acid, hydrochloric acid, perchloric acid, p- toluenesulfonic acid, methanesulfonic acid, an acidic catalyst such as trifluoromethanesulfonic acid; NaOH, KOH, basic, such as NH ₄ OH A catalyst or the like is used.

The ratio of the aldehyde compound to the aromatic hydroxy compound at the time of performing the condensation reaction is affected by the type of the aldehyde compound, the aromatic hydroxy compound, the solvent and the catalyst used, the reaction time, the reaction temperature and the like. However, the aldehyde compound is usually preferably 0.1 to 10 mol, particularly preferably 0.5 to 5 mol, per 1 mol of the aromatic hydroxy compound. The ratio of the nitrite and / or reducing saccharide to the aldehyde compound is usually preferably 0.1 to 10 mol per 1 mol of the aldehyde compound.

[Second layer of coating film] The coating solution for forming the second layer is as follows:
Water-soluble polymer compound (b-1), inorganic colloid (b-
2) at least one scale prevention auxiliary (B) selected from the group consisting of inorganic salts (b-3) and acids (b-4)
Is used.

<Water-soluble polymer compound (b-1)> Examples of the water-soluble polymer compound (b-1) include a water-soluble polymer compound having a hydroxyl group, a water-soluble amphoteric polymer compound, and a water-soluble polymer compound. And a water-soluble cationic polymer compound. Examples of the water-soluble polymer compound containing a hydroxyl group include starches such as amylose, amylopectin, and dextrin-phosphorylated starch, and animal viscous substances such as chitin; cellulose such as methyl cellulose, glycol cellulose, ethyl methyl cellulose, hydroxyethyl cellulose, and hydroxyethyl methyl cellulose. Derivatives; hemicelluloses such as xylan, mannan, alabogalactan, galactan, araban; alcohol lignin, dioxane lignin,
Lignins such as phenol lignin, hydrotropic lignin, mercapto lignin, alkali lignin, thioalkali lignin, acid lignin, copper oxide-ammonia lignin, periodate lignin; partially saponified polyvinyl alcohol; polyvinyl alcohol.

Examples of the water-soluble amphoteric polymer compound include glue, gelatin, casein, albumin, ribonucleic acid, deoxyribonucleic acid, and chitosan. As the water-soluble anionic polymer compound, a water-soluble anionic polymer compound having a carboxyl group or a sulfonic acid group in a side chain is used. For example, sulfomethylated polyacrylamide, polyacrylic acid, alginic acid, acrylamide-vinyl sulfone Acid derivatives, polymethacrylic acid,
Polystyrene sulfonic acid, carboxymethyl starch,
Pectic acid, pectinionic acid, protopectic acid, carrageenic acid, hyaluronic acid, chondroitin sulfate, heparin, kerado sulfate, thioglycolic acid ligninsulfonic acid, styrene-maleic anhydride copolymer, acrylic acid-
A maleic anhydride copolymer and carboxymethyl cellulose are exemplified.

As the water-soluble cationic polymer compound,
Cationic polyelectrolyte having a nitrogen atom in a side chain and the nitrogen atom bearing a positive load, for example, polyethyleneimine, polyvinylamine, polyacrylamide, N-
Vinyl-2-pyrrolidone / acrylamide copolymer, cyclized polymer of dimethyldiamylammonium chloride,
Cyclized polymer of dimethyldiethylammonium bromide, cyclic polymer of diallylamine hydrochloride, cyclic copolymer of dimethyldiallylammonium chloride and sulfur dioxide, polyvinyl pyridine, polyvinyl pyrrolidone,
Examples thereof include polyvinyl carbazole, polyvinyl imidazoline, polydimethylaminoethyl acrylate, polydiethylaminoethyl acrylate, and polydiethylaminoethyl methacrylate.

Among the water-soluble polymer compounds exemplified above,
Methylcellulose, hydroxyethylcellulose, hydroxyethylmethylcellulose, polyvinyl alcohol, partially saponified polyvinyl alcohol, glue, casein, gelatin, chitosan, polyacrylic acid, alginic acid, polymethacrylic acid, pectic acid, carrageenic acid, hyaluronic acid, carboxymethylcellulose, polyvinylpyrrolidone, Styrene-maleic anhydride copolymer is preferred.

<Inorganic colloid (b-2)> As the inorganic colloid, for example, aluminum, thorium, titanium,
Colloids of oxides and hydroxides of metals selected from zirconium, antimony, tin, iron, etc .; colloids of tungstic acid, vanadium pentoxide, selenium, sulfur, silica, gold and silver; silver iodide sol, etc. . Preferred among these are colloids of oxides and hydroxides of metals selected from aluminum, titanium, zirconium, tin and iron, and colloidal silica. The inorganic colloid may be obtained by any production method, and the production method is not particularly limited. For example, a particle colloid produced by a dispersion method using water as a dispersion medium or an aggregation method may be used. The size of the colloid particles is preferably from 1 to 500 nm.

<Inorganic Salt (b-3)> Examples of the inorganic salt include a silicate of an alkali metal and an inorganic salt of an alkaline earth metal. Examples of the alkali metal silicate include metasilicate (M ₂ SiO ₃ ) and orthosilicate (M ₄ Si) of an alkali metal such as lithium, sodium, and potassium.
O ₄ ), disilicate (M ₂ Si ₂ O ₃ ), trisilicate (M ₃ Si
₃ O ₇ ), sesquisilicic acid (M ₄ Si ₃ O ₁₀ ), and the like (where M represents an alkali metal such as lithium, sodium, and potassium), and water glass. As inorganic salts of alkaline earth metals, for example, silicates, carbonates, phosphates, sulfates, nitrates, borates, acetates, hydroxides of alkaline earth metals such as magnesium, calcium and barium , Oxides, halides and the like. Among these alkaline earth metal compounds, particularly preferred are magnesium carbonate, calcium carbonate, magnesium phosphate, calcium phosphate, calcium pyrophosphate, calcium dihydrogen pyrophosphate, barium phosphate, calcium sulfate, calcium borate, and magnesium hydroxide. , Calcium hydroxide, barium hydroxide, magnesium chloride and calcium chloride.

<Acid (b-4)> Examples of the acid include inorganic acids such as phosphoric acid, pyrophosphoric acid, polyphosphoric acid, phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, silicotungstic acid, molybdic acid and tungstic acid; Terephthalic acid, 1,12-dodecanedicarboxylic acid, 1-dodecanedisulfonic acid, benzoic acid, lauric acid, sulfanilic acid, p-styrenesulfonic acid, propionic acid, salicylic acid, copper phthalocyanine tetrasulfonic acid, urocanic acid, L-ascorbic acid And organic acids such as D-isoascorbic acid, chlorogenic acid, caffeic acid, p-toluenesulfonic acid, sorbic acid, β-naphthoquinone-4-sulfonic acid, phytic acid and tannic acid. Among at least one kind of scale prevention assistant (B) selected from the above-mentioned components (b-1) to (b-4), water-soluble polymer compound (b-1), inorganic colloid (b-2), inorganic Salt (b-3) is preferred, and water-soluble polymer compound (b-1) is particularly preferred.

The coating solution for the second stage coating is as described in the above (b-1)
It is prepared by dissolving at least one kind of scale preventing aid (B) selected from the components (b-4) in a suitable solvent.
As this solvent, water or a mixed solvent of water and a hydrophilic organic solvent miscible with water is used. Among the above organic solvents, examples of the hydrophilic organic solvent include alcohol solvents such as methanol, ethanol, and propanol; ketone solvents such as acetone and methyl ethyl ketone; and ester solvents such as methyl acetate and ethyl acetate. Further, among the above solvents, it is preferable to use an alcohol solvent.
When using a mixed solvent of water, a hydrophilic organic solvent and water, the content of the hydrophilic organic solvent should be such that there is no danger of ignition, volatilization, etc., and there is no problem in handling safety such as toxicity. More specifically, the content of the hydrophilic organic solvent is preferably 50% by weight or less, and more preferably 30% by weight or less. If necessary, a pH adjuster such as NaOH or ethylenediamine may be used. The above (b-
The concentration of the scale-inhibiting aid (B) in the coating solution when applying at least one scale-inhibiting aid (B) selected from the components (1) to (b-4) is in the range of 0.01 to 20% by weight. And more preferably 0.1 to 15% by weight.

[Steam Carrier] The steam used as a carrier with the coating solution may be ordinary saturated steam or superheated steam, and may be 0.196 to 3.43 MPa · G (2
Those having a pressure of ~ 35 kgf / cm ² · G) are more preferred.
The temperature of the steam is preferably from 120 to 260 ° C, from 130 to 200 ° C.
C is more preferred. The pressure and temperature of the steam are values measured before the steam is mixed with the coating liquid, for example, in the steam supply line 6 in FIG.

[Formation of Coating Film] The formation of a coating film comprising a first layer and a second layer according to the method of the present invention will be described with reference to the coating apparatus shown in FIG. FIG. 1 schematically shows the configuration of the polymerization apparatus. Step 1. (Preheating of inner wall of polymerization vessel by steam) Hot water or the like is passed through jacket 2 attached to polymerization vessel 1 to raise the temperature of the inner wall of the polymerization vessel to 50 ° C. or higher (preferably 50 to 95 ° C.).
(° C). At the top of this polymerization vessel, a downwardly directed nozzle 3a and an upwardly directed nozzle 3 are formed by an annular pipe.
An application ring 4 having b is provided. The coating ring 4 is connected to a line 5 for supplying steam and a coating solution from outside the polymerization vessel 1. The line 5 is connected to a steam supply line 6, a first application liquid supply line 7, and a second application liquid supply line 8 via a valve. If necessary, steam (steam or superheated steam) is blown into the vessel from the application nozzles 3a and 3b of the application ring 4, and a baffle (not shown) and a stirring blade (not shown) are also heated in advance. In this device, steam is supplied from a steam supply 9 via a flow meter 10 through lines 6 and 5 to the coating ring 4.

Step 2. (First-stage coating) Steam is supplied to the coating ring 4 and the first coating liquid tank 1
The first coating liquid contained in 1 is supplied to the coating ring 4 via lines 7 and 5 by a pump 12 or an aspirator valve (not shown). P is a pressure gauge. The first coating solution is transported to steam and applied in a mist state to a surface where the monomer comes into contact during polymerization, such as an inner wall surface of the polymerization vessel, a baffle surface, and a stirring blade surface, and is applied. At the same time as this coating, the first coating liquid applied on these surfaces is dried (simultaneous drying) to form a first layer. Therefore, no special operation for drying is required. The mixing ratio (L / G) of the steam (G) and the coating liquid (L) is 0.005 to 0.8 in terms of a weight-based flow ratio.
Is preferable, and 0.01 to 0.2 is more preferable.

Step 3. (Second-stage coating) The second coating solution stored in the second coating solution tank 13 is supplied to the line 8 using the pump 14 while the steam is continuously flowing.
And 5 are supplied to the coating ring 4 in the same manner, and coated on the first layer surface to form a second layer (not shown). As in the case of the first-stage coating, the second coating solution applied on the first layer is dried (simultaneous drying) at the same time as the application, and the second layer is formed, so that no special drying operation is required. . Also in this second-stage coating, the mixing ratio (L / G) of the steam (G) and the coating liquid (L) is preferably 0.005 to 0.8, more preferably 0.01 to 0.2, in terms of weight-based flow ratio.

Step 4. (Washing) After the supply of steam and the coating liquid is stopped, the inside of the polymerization vessel 1 is washed with the washing water stored in the water tank 15. Wash water is supplied by a pump 16 through a line 17 from a nozzle 18 into the polymerization vessel. However, if there is little influence on the quality, it is not necessary to wash with water. Dry coating amount of the thus first layer formed is preferably 0.0005~3g / m ^2, more preferably from 0.0005~1g / m ^2. The dry coating amount of the second layer is preferably 0.0005 to ² g / m ² , more preferably
0.0005 to 1 g / m ² . Total dry coating weight of the first and second layers is preferably 0.001 to 5 g / m ^2, more preferably from 0.001~2g / m ^2.

Polymerization The method of the present invention is applied to the polymerization of a monomer having an ethylenically unsaturated double bond. Examples of this monomer include vinyl halides such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid, methacrylic acid, and their esters or salts; maleic acid, fumaric acid, and the like. Esters or anhydrides; diene monomers such as butadiene, chloroprene and isoprene; styrene; acrylonitrile; vinylidene halide;

As an example in which the method of the present invention is particularly preferably practiced, suspension polymerization or emulsification of a vinyl halide such as vinyl chloride or a vinylidene halide, or a monomer mixture mainly containing them, in an aqueous medium is preferred. There is the production of these polymers by polymerization. Further, the coating film formed by the method of the present invention has high durability even for monomers having a high solubility for conventional coating films such as α-methylstyrene, acrylate, acrylonitrile, and vinyl acetate. Therefore, the production of polymer beads such as polystyrene, polymethacrylate and polyacrylonitrile, the production of latex, and the production of synthetic rubber such as SBR, NBR, CR, IR and IIR (these synthetic rubbers are usually produced by emulsion polymerization) )), And can be suitably carried out for the production of ABS resin.

In the polymerization of one or more of these monomers, irrespective of the type of polymerization such as suspension polymerization, emulsion polymerization, bulk polymerization, solution polymerization, and the like, emulsifiers, stabilizers, lubricants, plasticizers, Even in the presence of any additives such as a pH adjuster and a chain transfer agent, the purpose of preventing scale is effectively achieved. For example, in the case of suspension polymerization or emulsion polymerization of a vinyl monomer, various additives are added to the polymerization system as needed. Examples of the additives include a suspending agent such as partially saponified polyvinyl alcohol and methylcellulose; an anionic emulsifier such as sodium lauryl sulfate; a nonionic emulsifier such as sorbitan monolaurate and polyoxyethylene alkyl ether; Stabilizers such as calcium phosphate, dibutyltin dilaurate, and dioctyltin mercaptide; chain transfer agents such as trichloroethylene and mercaptans; and pH adjusters. According to the method of the present invention, even when such an additive is present in the polymerization system, scale adhesion is effectively prevented.

Further, the remarkable effect of preventing the adhesion of polymer scale of the present invention can be exhibited regardless of the type of the polymerization catalyst, regardless of the type of the polymerization catalyst. Specific examples of the catalyst include t-butyl peroxy neodecanoate, bis (2-ethylhexyl) peroxy dicarbonate, 3,5,5-trimethylhexanoyl peroxide, α-cumyl peroxy neodecanoate Ethate, cumene hydroperoxide, cyclohexanone peroxide, t-butyl peroxypivalate, bis (2-ethoxyethyl) peroxydicarbonate, benzoyl peroxide, diisopropylbenzene hydroperoxide, lauroyl peroxide, 2,4-di Chlorbenzoyl peroxide, diisopropyl peroxydicarbonate, α, α′-azobisisobutyronitrile, α, α′-azobis-2,4-dimethylvaleronitrile, di-2-ethylhexyl diperoxyisophthalate, Sulfuric acid Um, ammonium persulfate, and the like.

Other conditions for the polymerization may be the same as those conventionally performed, and are not particularly limited as long as the effects of the present invention are not impaired. Hereinafter, typical polymerization conditions will be specifically described with examples of suspension polymerization, solution polymerization, and bulk polymerization as examples.
There is no limitation to this. In the case of suspension polymerization, first, water and a dispersant are charged into a polymerization vessel, and then a polymerization initiator is charged. Next, the inside of the polymerization vessel is evacuated to 0.01 to 10
After reducing the pressure to 1 kPa (0.1 to 760 mmHg), the monomer was charged (at this time, the internal pressure of the polymerization vessel was usually 150 to 3040 kPa (0.5
3030 kgf / cm ² · G)], and then polymerize at a reaction temperature of 30 to 150 ° C. During polymerization, one or more of water, a dispersant, and a polymerization initiator are added as necessary. Also,
The reaction temperature during the polymerization differs depending on the type of the monomer to be polymerized. For example, in the case of vinyl chloride polymerization, the polymerization is performed at 30 to 80 ° C, and in the case of styrene, the polymerization is performed at 50 to 150 ° C. In the polymerization, the internal pressure of the polymerization vessel is 100 to 790 kPa (0 to 7 kgf / cm ²
-When the temperature drops to G) or when the difference between the inlet and outlet temperatures of the cooling water flowing into and out of the jacket provided on the outer periphery of the polymerization vessel has almost disappeared (that is, when the heat generated by the polymerization reaction has disappeared). Is determined to be completed. The water, dispersant and initiator charged during the polymerization are usually monomers 10
20 to 500 parts by weight of water, 0.01 to 30 parts by weight of a dispersant, and 0.01 to 5 parts by weight of a polymerization initiator, based on 0 parts by weight.

In the case of solution polymerization, an organic solvent such as toluene, xylene and pyridine is used as a polymerization medium instead of water. A dispersant is used as needed.
Other polymerization conditions are generally the same as the polymerization conditions for suspension polymerization.

In the case of bulk polymerization, about 0.001
After evacuating to a pressure of ~ 101 kPa (about 0.01 to 760 mmHg), a monomer and a polymerization initiator were charged into the polymerization vessel, and -10 to 25
Polymerize at a reaction temperature of 0 ° C. For example, in the case of vinyl chloride polymerization, the polymerization is carried out at 30 to 80 ° C, and in the case of styrene polymerization, the polymerization is carried out at 50 to 150 ° C.

[0050]

The present invention will be described in detail below with reference to examples and comparative examples. In addition, "part" means "part by weight", and "auxiliary agent" in the table means "polymer scale adhesion preventing auxiliary agent". Production of Condensation Product In the following Production Examples, the weight average molecular weight of the obtained condensation product was measured as follows.

Measurement of Weight Average Molecular Weight The weight average molecular weight in terms of polystyrene was measured by gel permeation chromatography (GPC) under the following measurement conditions. Column: Guard column Brand name shim-pack GPC-800DP, Shimadzu Corporation Analytical column Brand name shim-pack GPC-803D, 802D, Shimadzu Corporation Mobile phase: 10 mM LiBr / DMF Flow rate: 1.0 ml / min Detector: RI temperature: 60 ℃

Production Example 1 Production of condensate No. 1 (Comparative production example using neither nitrite nor reducing sugar) Production of polymer scale adhesion inhibitor with reference to Production Example 1 of JP-A-57-164107 did. 1-naphthol for pressure-resistant reactor
250 mol (36.0 kg) and 1N NaOH aqueous solution (NaOH 180 mol,
180 L was charged, and the temperature was raised to 70 ° C. while stirring. Next, formaldehyde (38 w / v) was added to the reaction mixture.
% Aqueous solution (19.75 L, 250 mol) was added dropwise over 1.5 hours. During this time, the internal temperature of the reactor was kept from exceeding 80 ° C. The reaction mixture is then stirred for 60
Cooled to ° C. Next, the reaction mixture was heated to 98 ° C.
For 1.5 hours. Thereafter, the reaction mixture was cooled to obtain an alkaline solution of a condensate (condensate No. 1). Condensate N
The weight average molecular weight of o.1 was 2,400.

Production Example 2 Production of Condensate No. 2 In a pressure-resistant reactor, 250 mol (36.0 kg) of 1-naphthol and 1N
180 L of an aqueous NaOH solution (containing 180 mol of NaOH and containing 7.2 kg) was charged, and the temperature was raised to 70 ° C. with stirring. Next, formaldehyde (19.75 L of a 38 w / v% aqueous solution, 250 mol) was added dropwise to the reaction mixture over 1.5 hours. Immediately after the end of the formaldehyde addition, sodium nitrite (20% w / w aqueous solution 17.2) was added.
5 kg, 50 mol) was added over 0.1 hour. During this time, the internal temperature of the reactor was kept from exceeding 80 ° C. The reaction mixture was then cooled to 60 ° C. over 3 hours with continued stirring. Next, the reaction mixture was heated to 98 ° C. and reacted at 98 ° C. for 1.5 hours. Thereafter, the reaction mixture is cooled and the condensate (condensate No.
2) An alkaline solution was obtained. The weight average molecular weight of the condensate No. 2 was 2,300.

Production Example 3 Production of Condensate No. 3 250 mol (36.0 kg) of 1-naphthol, 50 mol (3.2 kg) of ammonium nitrite and a 1N aqueous solution of NaOH (NaO
180 mol of H (containing 7.2 kg) was charged, and the temperature was raised to 70 ° C. while stirring. Next, formaldehyde (19.75 L of a 38 w / v% aqueous solution, 250 mol) was added dropwise to the reaction mixture over 1.5 hours. During this time, the internal temperature of the reactor was kept from exceeding 80 ° C. The reaction mixture was then cooled to 60 ° C. over 3 hours with continued stirring. Next, the reaction mixture was heated to 98 ° C. and reacted at 98 ° C. for 1.5 hours. Thereafter, the reaction mixture was cooled to obtain an alkaline solution of a condensate (condensate No. 3). The weight average molecular weight of the condensate No. 3 was 2,100.

Production Example 4 Production of Condensate No. 4 A scale inhibitor was produced with reference to Synthesis 2 of the coating compound of JP-A-57-192413. Pyrogallol 10 in pressure reactor
0 mol (12.6 kg), 30 mol of glucose (5.4 kg) and 100 L of water
And pyrogallol was dissolved in water. Next, 200 mol (21.2 kg) of benzaldehyde and 300 mol (29.4 kg) of phosphoric acid were added to the resulting solution, and the mixture was added at 95 ° C. for 1 hour.
After reacting for 0 hours, a red-brown product insoluble in water was obtained. After washing the water-insoluble product with ether, a methanol-soluble component is extracted from the water-insoluble product with methanol, and then methanol is removed from the extract by drying to obtain a condensate No. 4 as a residue. Was. The weight average molecular weight of this condensate No. 4 was 4,000.

Production Example 5 A polymer scale adhesion inhibitor was produced with reference to Production Example 3 of JP-B-6-62709, except that nitrite was added to the reaction mixture during the production reaction of condensate No. 5 . In a pressure-resistant reactor, 30 mol (2,9'-dihydroxybiphenyl) (5.59 kg), 30 mol (0.948 kg) of 95% pure paraformaldehyde, and 0.2 mol of p-toluenesulfonic acid were added.
19 kg and 10 L of ethylene glycol dimethyl ether were charged, and the temperature was raised to 130 ° C. while stirring. When the temperature reaches 130 ° C, lithium nitrite (6.6 kg of a 20% w / w aqueous solution, 25 mol) is added.
Added over 0.1 hour. Next, the mixture was reacted at 130 ° C. for 17 hours, cooled to 50 ° C., and the reaction mixture was poured into 50 L of water. The resin precipitated by being poured into water was filtered, washed with water and dried to obtain 5.1 kg of a 2,2'-dihydroxybiphenyl-formalin condensed resin (condensate No. 5). The weight average molecular weight of the condensate No. 5 was 5,200.

<Preparation of First Coating Solution> Preparation of First Coating Solution Nos. 101 to 111 [ Condensate (A), auxiliary (B), pH adjuster, (A) / ( B), the weight ratio of (B), the total concentration of (A) + (B), the solvent composition, and the pH] are shown in Table 1.
A first coating solution for forming a first layer was prepared using a pH adjuster and a solvent. However, the coating liquid No. 102 is a coating liquid containing a scale inhibitor prepared at a low concentration for spray coating.
In the following table, the condensate is abbreviated as CP. For example,
“CP 5” means “condensate No. 5”.

[0058]

[Table 1]

<Preparation of Second Coating Solution> Preparation of Second Coating Solution Nos. 201 to 218 The conditions shown in Tables 2 and 3 [Auxiliary (B) of (b-1) to (b-4), (B-1) / (b-2) to (b-4) weight ratio, total concentration of (B), solvent, pH adjuster and pH] to prevent scale prevention shown in Tables 2 and 3. Auxiliaries (B),
Using a pH adjuster and a solvent, a coating solution containing a scale prevention aid (for second-stage coating) was prepared. However, coating liquid No. 202 *
Is a comparative polymer scale adhesion preventing aid-containing coating solution used for spray coating. In addition, since the water-soluble polymer compound (b-1) hardly dissolves at room temperature in the coating solution using the water-soluble polymer compound, the solvent was heated to about 70 ° C. and dissolved.

[0060]

[Table 2] [for second-stage coating (part 1)]

[0061]

[Table 3] [For second stage application (No. 2)]

Example 1 FIG. 2 schematically shows the structure of a polymerization apparatus. Regarding the polymerization vessel, the same elements as those in FIG. 1 are indicated by the same reference numerals. The following experiment was performed using the polymerization apparatus shown in FIG. In FIG. 2, a SUS 316 L stainless steel polymerization vessel 1 having an internal volume of 2 m ³ is provided with a stirring device 21 having a stirring blade 20 (a stirring motor is not shown), a heating / cooling jacket 2, a manhole 22, a baffle 23, Other accessory equipment (not shown) usually provided in a polymerization vessel for vinyl chloride polymerization is provided. A line 24 connected to the upper part of the polymerization vessel 1 is a raw material charging line, and a vinyl chloride monomer (V
CM) charging line 24a, catalyst solution charging line 24b,
Branch lines such as a suspension agent solution charging line 24c and a pure water charging line 24d are connected. The valves V1, V2,
V3, V4 and V5 are provided. In addition, polymerization vessel 1
A line 25 connected to the upper part of the reactor 25 is provided for exhausting the inside of the polymerization reactor 1, recovering monomers, and the like, and is led to a gas holder 27 via a line 26 branched from the line 25. A monomer recovery line 28 is led out of the gas holder 27, and a line 29 led out of the gas holder 27 is connected to a line 25 and used for a pressure equalizing operation described later. These lines 25, 26, 28 and 29 have valves V6, V7, V8, V9, V10, V11, V1
2 and V13 are provided. The line 26 branches into a line 26a provided with a vacuum pump 30 used for evacuation of the polymerization vessel 1, a monomer recovery and the like, and a line 26b not provided with such a pump, and then again. One line is connected to the gas holder 27. Further, a line 31 is connected to an upper portion of the polymerization vessel 1 in order to wash the inside of the polymerization vessel with water. The valve 14 is provided in the line 31 at the position shown in the figure, and a nozzle 32 is provided at a tip guided into the vessel. Further, a first coating liquid supply line 34 and a second coating liquid supply line 35 are connected to a coating liquid supply line 33 via a valve as shown in the upper part of the polymerization vessel 1. Further, a steam supply line 36 is connected to the line 33 via a valve. The application nozzles 3a and 3b
Is provided with an application ring 4 provided with. These lines have valves V15, V16, V17
And V18 are provided. Steam supply line 36
Is provided with a valve 19 at the position shown. A line 37 is connected to the bottom of the polymerization vessel 1 and is divided into a line 38a for guiding a polymer slurry to a blow-down tank and a line 38b for discharging a coating liquid or the like and washing water to a wastewater tank. Valves V20, V21 and V22 are located at the illustrated positions in each of these lines 38, 38a, 38b.
Is provided.

Table 4 shows the number of the coating solution used in each experiment. In advance, a coating solution is applied to the surface of the inner wall of the polymerization vessel or the like by a method described later, and if necessary, the polymerization of the vinyl chloride monomer is repeated in the polymerization vessel in which the coating film is formed by drying as follows. Was. (1) Coating and drying The following a), on the inner wall of the polymerization vessel of the polymerization apparatus shown in FIG.
A coating film is formed by the method of b), c) or d). In addition,
The methods a), b) and c) are the methods of the comparative examples. In the description of each method, it is assumed that all valves are initially closed.

A). One-step spray application and drying Hot water is passed through the jacket 2 to heat the inner wall surface of the polymerization vessel 1 to a temperature of 70 ° C. (Preheating time in jacket; 10
Minutes) The valves V17, V16, V15, V20, and V22 are opened, and the first coating solution containing a scale adhesion inhibitor is applied at a flow rate of 5 L / min for 1.5 minutes. Valve V17, V1
6, V15, V20 and V22 are closed, and valves V6, V8 and V
13. Open V9, start the vacuum pump 30, and apply 8.0 kPa (-7
The pressure is reduced to 00 mmHg), and the wet coating film is dried (necessary drying; drying time: 25 minutes) to form a coating film. Thereafter, the vacuum pump is stopped, and the valves V8, V13, and V9 are closed. Next, the valves V7 and V10 are opened to make the internal pressure of the polymerization vessel 1 the same as the internal pressure of the gas holder 27. After that, valves V6 and V
7. Close V10. The flow of the hot water to the jacket 2 is stopped.

B). Two-stage spray application and drying Hot water is passed through the jacket 2 to heat the inner wall surface of the polymerization vessel 1 to 70 ° C. (preheating time in the jacket: 10 minutes). Valves V17, V16, V15, V20,
V22 is opened, and a coating solution containing a scale adhesion inhibitor (undercoat) is applied at a flow rate of 5 L / min for 1.5 minutes. Valve V1
7, V16, V15, V20, V22 are closed and the valve V
6, open V8, V13, V9, start the vacuum pump 30,
The pressure is reduced to 8.0 kPa (−700 mmHg), and the coating solution is dried (necessary drying; drying time: 25 minutes) to form a first layer. Thereafter, the vacuum pump is stopped, and the valves V8, V13, and V9 are closed. Next, the valves V7 and V10 are opened to make the internal pressure of the polymerization reactor 1 the same as the internal pressure of the gas holder 27. Then V
6. Close V7 and V10. Next, the valves V18, V1
6, V15, V20 and V22 are opened, and a coating solution containing a polymer scale adhesion preventing aid (overcoat) is applied at a flow rate of 5 liter / min.
Apply on the first layer for 1.5 minutes. Valve V18, V
16, V15, V22 and V20 are closed and valves V6 and V
8, open V13, V9, start the vacuum pump 30, and 8.0k
The pressure is reduced to Pa (-700 mmHg), and the coating solution is dried (needing drying;
Drying time: 25 minutes), forming a second layer. Thereafter, the vacuum pump is stopped, and the valves V8, V13, and V9 are closed. Then V
7. Open V10 and reduce the internal pressure of polymerization reactor 1 to gas holder 27.
To the same pressure as the internal pressure. Thereafter, V6, V7 and V10 are closed.
The flow of the hot water to the jacket 2 is stopped.

C). One-step steam application (and simultaneous drying) Hot water is passed through the jacket 2 to heat the inner wall of the polymerization vessel 1 to 70 ° C. (preheating time in the jacket: 10).
Minutes). Open the valves V19, V22, V20, V15 and V16 and apply steam of 392 kPa · Gauge (4 kgf / cm ² · G) (143 ° C) to 2
The steam was blown into the polymerization vessel at a flow rate of 40 kg / Hr for 3 minutes, and after preheating the inside of the vessel, the valve V17 was opened, and the coating solution containing a scale adhesion inhibitor was sprayed at a flow rate of 0.2 L / min for 2 minutes. Coating and simultaneous drying using as a carrier. After that, valves V19, V22, V20, V15, V16,
Close V17. The flow of the hot water to the jacket 2 is stopped.

D). Two-stage steam coating (and simultaneous drying) (1) Coating and drying Hot water is passed through the jacket 2 to heat the inner wall of the polymerization vessel 1 to 70 ° C. (jacket) Preheating time: 10 minutes). Valves V19, V22, V20, V15, V1
6 is opened and steam of 392 kPa · Gauge (4 kgf / cm ² · G) (143 ° C.) is blown into the polymerization vessel 1 at a flow rate of 240 kg / Hr for 3 minutes.
After preheating the inside of the vessel, the valve V17 is opened, and the first coating solution containing a scale adhesion inhibitor (for undercoating) is applied at a flow rate of 0.2 L / min for 2 minutes using the steam as a carrier and simultaneously dried to form a first layer. Form. Thereafter, the valve V17 is closed.
Next, the valve V18 is opened, and a second coating solution containing an auxiliary agent (for overcoating) is applied onto the first layer at a flow rate of 0.2 liter / min for 1 minute by using the steam carrier and dried at the same time. Is applied. Then, valves V19, V22, V2
0, V15, V16 and V18 are closed. The flow of the hot water to the jacket 2 is stopped.

(2) Second Rinsing in Vessel Open valves V14, V20, V22, V6, V7, V10 to rinse the inside of the vessel, and discharge the flushed water to a wastewater tank. The valves V14, V20, V22 are closed. A) above
Alternatively, when the method of b) is used, the washing time is 4 minutes. When the above method c) or d) is used, the washing time is 1 minute.

(3) Charging The valves V1, V2, and V3 are opened, and 200 parts by weight of pure water, 0.022 parts by weight of partially saponified polyvinyl alcohol, and 0.028 parts by weight of hydroxymethyl cellulose are charged into the polymerization vessel 1.
The valves V1, V2, V3, V6, V7, V10 are closed. Next, the valves V1 and V5 are opened, 100 parts by weight of vinyl chloride monomer (VCM) are charged, and the valve V5 is closed.
Next, while stirring the charged raw materials, the valve V4 is opened, 0.03 parts by weight of t-butyl peroxyneodecanate is charged, and the valves V1 and V4 are closed. (4) Polymerization While stirring the charged raw materials, hot water was passed through the jacket 2 to raise the temperature. When the internal temperature reached 52 ° C, the internal temperature was maintained at 52 ° C by passing cooling water through the jacket 2. Polymerization was performed. The polymerization was terminated when the pressure in the vessel dropped to 490 kPa · Gauge (5 kgf / cm ² · G). (5) Exhaust gas The valves V6, V8, V12, and V9 are opened, and the exhaust gas is exhausted to the gas holder 27 until the internal pressure becomes substantially atmospheric pressure.
Thereafter, the valves V12, V8, and V9 are closed. Valve V1
1. Open V10 and send the monomer recovered in the gas holder 27 to the VCM recovery process via the line 28, and then close the valves V11 and V10.

(6) Equalization The valves V7 and V10 are opened to make the internal pressure of the polymerization vessel 1 equal to the internal pressure of the gas holder 27 (equalization). (7) Slurry extraction Valves V20 and V21 are opened, and the polymer slurry is extracted from the vessel into a blowdown tank (not shown). The polymer slurry discharged to the blowdown tank is then dehydrated and dried to obtain a vinyl chloride polymer product. (8) First Rinsing Vessel Open the valve V14 to rinse the inside of the polymerization vessel 1 and send the cleaning water to the blowdown tank. Then the valves V14, V20,
V21, V6, V7 and V10 are closed. During the water washing in this vessel, the temperature of the polymerization vessel wall was passed by passing hot water through the jacket 2.
Keep at 70 ° C. The operations from the above-mentioned coating and drying (1) to the first washing (8) after the completion of the polymerization were regarded as one batch, and the same operation was repeated for the number of batches shown in Table 6.

<Evaluation> Time required for forming a coating film Table 5 shows the time required for forming a coating film in Examples and Comparative Examples.
Shown in ・ Measurement of polymer scale adhesion amount In each experiment, after the final batch, the polymer scale adhesion amount in the liquid phase part in the polymerization vessel, the polymer scale near the interface between the stirring blade and baffle surface and the interface between the gas phase part and the liquid phase part The amount of adhesion was determined by the following method. The scale adhering to an area of 10 cm × 10 cm on the surface of the object was scraped off with a spatula as far as the naked eye could confirm, and weighed with a balance. By multiplying the measured value by 100, the amount of scale adhered per 1 m ² was obtained. Table 6 shows the results. -Measurement of fish eye In each experiment , the fish eye obtained when the polymer obtained after the end of the final batch was molded into a sheet was measured by the following method. Table 7 shows the results. 100 parts by weight of polymer, 50 parts by weight of dioctyl phthalate, 1 part by weight of dibutyltin dilaurate, 1 part by weight of cetyl alcohol, 0.25 of titanium oxide
Parts by weight and 0.05 parts by weight of carbon black were kneaded for 7 minutes at 150 ° C. using a 6-inch roll, and then formed into a sheet having a thickness of 0.2 mm. The number of fish eyes per 100 cm ^{2 of the} obtained sheet was examined by a light transmission method.

Measurement of lightness index (L value) In order to evaluate the initial coloring when the polymer was molded into a sheet, the lightness index (L value) was measured by the following method. Table 7 shows the results. 100 parts by weight of the obtained polymer, 1 part by weight of a dibutyltin laurate-based stabilizer (TS-101, manufactured by Akishima Chemical Co., Ltd.) and a cadmium organic complex-based stabilizer (C-100, manufactured by Katsuta Kako Co., Ltd.)
J) 0.5 parts by weight and dioctyl phthalate as a plasticizer
The mixture of 50 parts by weight was heated to 160 ° C. using a two-roll mill.
After kneading for 5 minutes, a sheet having a thickness of 1 mm was formed. The sheet obtained was placed in a 4 × 4 × 1.5 cm formwork,
A sample for measurement was prepared by applying a pressure of 6.37 to 6.87 MPa · Gauge (65 to 70 kgf / cm ² · G) at a temperature of 0 ° C. The lightness index L of this sample was determined as follows.

First, in accordance with JIS Z 8722, using standard light C and a photoelectric colorimeter (Z-1001 DP type colorimetric colorimeter manufactured by Nippon Denshoku Industries Co., Ltd.), XYZ colorimetry was performed by a stimulus value direct reading method. The stimulus value Y of the system was determined. Here, as the geometrical conditions for illumination and light reception, condition d described in JIS Z 8722, section 4.3.1, was employed. Next, the obtained stimulus value Y was substituted into the Hunter's color difference equation: L = 10Y1 ^{/ 2} described in JIS Z 8730 (1980) to calculate the L value. The larger the L value, the higher the whiteness, that is, the better the initial coloring.

Measurement of Colored Particles In each experiment, 100 parts by weight of the polymer obtained after the end of the final batch,
As a stabilizer [TVS N-2000E, manufactured by Nitto Kasei Co., Ltd.] 2
Parts by weight, and a mixture of 20 parts by weight of dioctyl phthalate as a plasticizer, after sufficiently kneading, 160 mm × 130 mm × 3 mm
175 ° C, 3.43MPaGauge (35kgf / cm ²
-The sample for measurement was produced by press-molding under the pressure of G). This sample was visually examined for the number of colored particles. Table 7 shows the results.

[0075]

[Table 4] *: Comparative example

[0076]

[Table 5]

[0077]

[Table 6] *: Comparative example

[0078]

[Table 7] Scale coverage and quality *: Comparative example

[0079]

According to the polymerization method of the present invention, the time required for forming a coating film such as a scale inhibitor is shortened to improve the productivity, and when the vinyl chloride monomer is polymerized, the polymerization time in the polymerization vessel is reduced. The adhesion of the polymer scale can be effectively prevented not only on the liquid phase wall surface, but also on the stirring device, the baffle surface facing the wall surface, near the interface between the gas phase and the liquid phase, and the like. For this reason, the quality of the obtained polymer product is improved,
In addition to being able to significantly reduce the number of colored particles in the polymer as compared to the related art, a molded product obtained by molding the polymer into a sheet or the like includes:
Very few fish eyes and very little initial coloring.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a polymerization apparatus for performing the method of the present invention.

FIG. 2 is a schematic diagram of another polymerization apparatus for performing the method of the present invention.

[Explanation of symbols]

 1. Polymerizer 4. Application ring 6. 6. Steam supply line 7. First coating liquid supply line Second coating liquid supply line 17. Cleaning water supply line 20. Stirrer blade 23. Baffle 24. Raw material supply line 27. Gas holder 31． Cleaning water supply line 34. First coating liquid supply line 35. Second coating liquid supply line 36. Steam supply line

 ────────────────────────────────────────────────── ─── Continued on the front page F-term (reference) 4J011 AA01 DA01 DA02 DA03 DA04 DB14 EB04 EB05 EB08 EB09 EB10 EB14 JA07 JA08 KA04 KA10 4J033 CA01 CA02 CA04 CA05 CA12 CA18 CA19 CA22 CA26 CA28 CA36 CB02 CB03 CC03 HA02 HA09B

Claims (5)

[Claims] 1. A method for producing a polymer, comprising polymerizing a monomer having an ethylenic double bond in a polymerization vessel, wherein said polymerization vessel has an inner wall surface and said monomer is polymerized during polymerization. Having a polymer scale anti-adhesion coating on the other surface in contact with the coating; the coating comprising a first layer formed on the inner wall surface and other surfaces; The first layer performs a condensation reaction between the aldehyde compound and the aromatic hydroxy compound in the presence of at least one selected from the group consisting of nitrites and reducing sugars. The first coating solution containing the condensate (A) obtained by the above, is formed by applying using steam as a carrier, the second layer, the first layer, water-soluble Made of polymer compound, inorganic colloid, inorganic salt and acid Ethylene formed by applying a second coating solution containing at least one polymer scale adhesion preventing assistant (B) selected from the group, using a steam as a carrier; A method for polymerizing a monomer having an acidic double bond. 2. The method according to claim 1, wherein at least one selected from the group consisting of nitrites and reducing sugars is added to the reaction mixture immediately before the start of the condensation reaction to the middle stage of the reaction. 2. The composition according to claim 1, wherein said composition is added.
The method described in. 3. The method according to claim 1 or 2, wherein
The method according to claim 1, wherein the condensate (A) contained in the first coating liquid is a condensation product having a weight average molecular weight of an aromatic compound of 500 or more. 4. The method according to claim 3, wherein the weight-average molecular weight of the condensation product is from 500 to 70,000. 5. The method according to claim 1, wherein in both the application of the first coating liquid and the application of the second coating liquid, the water vapor (G) used as a carrier and the coating liquid (L) are used.
The mixing ratio (L / G) is 0.005 by weight based flow rate ratio.
方法 0.8.