JP2005097601A - Polymer scale adhesion inhibitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer scale adhesion inhibitor which can form a scale inhibiting coating film having a sufficient scale adhesion inhibiting performance by a one-step coating, improves productivity by shortening a process time, and even when many polymerization batches in high-temperature polymerization reaction conditions are repeated, inhibits polymer scale adhesion onto a internal wall surface, etc. of a polymerizer, and can obtain a polymer product having improved quality, and to provide a polymerizing method using the inhibitor. <P>SOLUTION: The polymer scale adhesion inhibitor for polymerizing a monomer having an ethylenically double bond which comprises (A) a condensation reaction product obtained by reacting an aldehyde compound and an hydroxynaphthalene compound in the presence of a reducing agent, and (B) a nitrogen atom-containing polymer compound. The polymerizing method using the inhibitor is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention polymerizes a monomer having an ethylenic double bond in a polymerizer, and prevents the polymer scale from adhering to the inner wall surface of the polymerizer when producing a polymer. It relates to the agent.

It is known that when a monomer having an ethylenic double bond is polymerized, the polymer adheres to the inner wall surface of the polymerization vessel as a scale.
The adhesion of the polymer scale becomes remarkable as the number of polymerization batches is increased, and the yield of the polymer, the cooling capacity in the polymerization vessel, and the like are reduced. Further, there is a problem that the polymer scale peeled off from the inner wall surface of the polymerization vessel is mixed with the obtained polymer and the quality of the product is lowered. And the removal work of the polymer scale adhered to the inner wall surface of the polymerization vessel not only requires excessive labor and time, but also the risk that unreacted monomers contained in the polymer scale may damage the human body. There is also.

  Conventionally, in order to prevent the polymer scale from adhering to the inner wall surface of the polymerization vessel during the polymerization of the monomer having an ethylenic double bond, the polymer scale adhesion preventing agent is attached to the inner wall surface of the polymerization vessel, a stirrer, etc. A method of forming a coating film by coating a coating is known. Examples of the polymer scale adhesion preventing agent include, for example, a condensation reaction product of naphthols and an aldehyde compound and a mixture of inorganic colloids (further, a water-soluble polymer compound) (Patent Document 1), sodium hydroxymethanesulfinate, A mixture of a reaction product with naphthols and polyvinyl alcohol (Patent Document 2, Patent Document 3) and the like are known.

  However, for example, a polymer scale adhesion-preventing coating film formed using the polymer scale adhesion preventing agent described in Patent Document 1 is a polymerizer particularly in the case of a polymerization reaction at a polymerization temperature of about 60 ° C. or higher. It was revealed that the polymer scale adhesion preventing effect in the vicinity of the gas-liquid interface was insufficient. Furthermore, when the number of polymerization batches increases to about 150 batches or more, the polymer scale attached to the vicinity of the gas-liquid interface grows, and when the degree of growth increases, the polymer is finally mixed into the polymer obtained by peeling. There was a problem of causing fish eyes of the combined product.

  Conventionally, when the number of repetitions of the polymerization batch increases, as a result of the repeated application of the polymer scale adhesion preventing agent to the inner surface of the polymerization vessel, etc., the scale inhibitor layer becomes gradually thicker, and this layer is partially peeled off. There was a problem that it was mixed in the obtained polymer and contained as colored particles in the polymer product, or the molded product showed discoloration such as yellowing. The phenomenon is called initial coloring.

JP-A-6-206909 Japanese National Patent Publication No. 11-506495 Japanese National Patent Publication No. 11-511495

  An object of the present invention is a polymer scale adhesion preventive agent for producing a polymer by polymerization of a monomer having an ethylenic double bond, and a polymer scale adhesion preventive coating film on an inner wall surface of a polymerization vessel. (Hereinafter referred to as “scale preventive coating”) can be completed by one-step application of the polymer scale anti-sticking agent, so that productivity can be improved. Even in the above polymerization reaction at a high temperature, and even when the number of polymerization batches increases to about 150 batches or more, the polymer scale adhesion prevention effect is sufficiently exerted, and the peel scale and coloration of the resulting polymer product are achieved. It is an object of the present invention to provide the polymer scale anti-adhesive agent which can improve the quality of the product by reducing the contamination of the particles and, as a result, significantly reducing the fish eye and initial coloration.

In order to achieve the above object, the present invention has been completed as a result of intensive studies.
That is, the present invention relates to an ethylene (A) condensation reaction product obtained by reacting an aldehyde compound and a hydroxynaphthalene compound in the presence of a reducing agent, and (B) a nitrogen atom-containing polymer compound. The present invention provides a polymer scale adhesion preventive agent (hereinafter referred to as “scale preventive agent”) for monomer polymerization having an ionic double bond.
The present invention further comprises the step of polymerizing a monomer having an ethylenically unsaturated double bond in a polymerization vessel having an inner wall surface and a coating film having a scale-inhibiting property on a portion contacting the monomer during polymerization. A method for producing a monomer polymer provides a method for producing a polymer, wherein the scale-preventing coating film comprises the above-mentioned scale inhibitor.

  The scale preventive agent of the present invention can form a scale preventive coating film having sufficient scale adhesion preventing performance by one-step coating, shortening the process time and improving productivity, and at a high number of times under high temperature polymerization reaction conditions. Even if the polymerization batch is repeated, not only the liquid phase wall in the polymerization vessel but also the vicinity of the gas-liquid interface, the stirrer, the baffle surface facing the wall, etc., effectively prevent the adhesion of the polymer scale. be able to. For this reason, not only can the colored particles be mixed into the polymer much less than the conventional one, but the molded product obtained by molding the polymer into a sheet or the like has very little fish eye and is resistant to damage. The initial colorability is extremely excellent, and a polymer product with improved quality can be obtained.

Hereinafter, the present invention will be described in detail. In the present specification, “initial color” means discoloration that occurs when a polymer product is molded under heat and pressure, and “anti-initial color” means resistance to such discoloration. .
[(A) Condensation reaction product]
The component (A) is a condensation reaction product obtained by subjecting an aldehyde compound and a hydroxynaphthalene compound to a condensation reaction in a solvent in the presence of a reducing agent.
The condensation reaction for obtaining the component (A) will be described in detail below.

<Aldehyde compound>
As the aldehyde compound which is a reaction raw material of the component (A), any organic compound having an aldehyde group (—CHO) can be used without particular limitation. Examples of the aldehyde compound include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, acrolein, crotonaldehyde, benzaldehyde, furfural, phenylacetaldehyde, 3-phenylpropionaldehyde, 2-phenylpropionaldehyde and the like. These can be used singly or in combination of two or more.
Among the aldehyde compounds exemplified above, formaldehyde and acetaldehyde are preferable from the industrial and economic viewpoints.

<Hydroxynaphthalene compound>
The hydroxy naphthalene compound which is a reaction raw material of the component (A) is an organic compound having a naphthalene ring skeleton, and at least one hydrogen atom bonded to the carbon atom forming the skeleton is substituted with a hydroxyl group. Any compound can be used without particular limitation. Examples of the hydroxynaphthalene compound include 1-naphthol, 2-naphthol, 1,3-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 6-hydroxy-2-naphthoic acid, 2- Examples thereof include hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, 8-hydroxy-1-naphthoic acid and the like. These can be used singly or in combination of two or more.
Of the hydroxynaphthalene compounds exemplified above, 1-naphthol and 2-naphthol are preferred.

<Reaction raw material usage ratio>
The proportion of the aldehyde compound and hydroxynaphthalene compound used for the condensation reaction may need to be adjusted depending on the type of both, the type of solvent and catalyst, the condensation reaction conditions, etc. The mole number of the aldehyde group (—CHO) contained in the aldehyde compound with respect to 1 mole of the hydroxyl group contained in the hydroxynaphthalene compound is usually 0.1 to 10 moles, particularly 0.5 to 5 moles. Is preferred.

<Condensation reaction solvent>
The solvent used in the condensation reaction of the two reaction raw materials is water, an organic solvent, or a mixed solvent thereof.
The organic solvent is not particularly limited as long as it can dissolve both the reaction raw materials and form a uniform solution, but a water-soluble organic solvent is preferable. Examples of the organic solvent include alcohols such as methanol, ethanol and propanol; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; and the following general formula (1):

(1)
（式中、Ｒ¹ は炭素原子数１〜３のアルキル基であり、Ｘはメチレン基（-ＣＨ₂-）または式：-ＮＲ²-(Ｒ² は炭素原子数１〜３のアルキル基)で表される２価の基である）
で表される化合物、等が挙げられる。これらは１種単独でも２種以上の混合溶媒としても使用することができる。また、上記のとおり、これらの有機溶媒と水との混合溶媒を用いることもできる。

(1)
Wherein R ¹ is an alkyl group having 1 to 3 carbon atoms, X is a methylene group (—CH ₂ —) or a formula: —NR ² — (R ² is an alkyl group having 1 to 3 carbon atoms) Is a divalent group represented by
And the like. These can be used alone or as a mixed solvent of two or more. Moreover, as above-mentioned, the mixed solvent of these organic solvents and water can also be used.

In the general formula (1), R ¹ is an alkyl group having 1 to 3 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Among these, a methyl group is preferable. When X is a group represented by the formula: —NR ² —, R ² is the same alkyl group as described for R ¹ , preferably a methyl group.
Examples of the compound represented by the general formula (1) include N-methyl-2-pyrrolidone, N, N′-dimethyl-2-imidazolidone, N-ethyl-2-pyrrolidone, N, N′-diethyl. -2-imidazolidone, N-propyl-2-pyrrolidone, N, N′-dipropyl-2-imidazolidone, and the like, preferably N-methyl-2-pyrrolidone, N, N′-dimethyl-2-imidazolidone It is. As described above, the compounds can be used singly or in combination of two or more.

  Among the solvents, the compound represented by the general formula (1), particularly N-methyl-2-pyrrolidone, N, N′-dimethyl-2-imidazolidone or a mixed solvent thereof, or the general formula (1) A mixed solvent of the represented compound and water is preferred. The reason is that the hydroxy naphthalene compound, which is a raw material for the reaction, has good solubility, and a uniform solution of the condensation reaction product can be obtained after the condensation reaction without forming a precipitate in the condensation reaction. This is because it can be effectively avoided that the precipitate derived from the condensation reaction is mixed into the polymer product.

When a mixed solvent of the compound represented by the general formula (1) and water is used, the use ratio is not particularly limited, but is usually 2 to 500 parts by weight, preferably 5 parts per 100 parts by weight of water. It is good to set it as the range of -200 weight part.
Further, the amount of the solvent used may be an amount that can dissolve both the reaction raw materials and form a uniform solution, and can obtain a uniform solution of the condensation reaction product after completion of the condensation reaction. Although not limited, the amount is usually in the range of 2 to 500 parts by weight, preferably 5 to 200 parts by weight with respect to 100 parts by weight of the total of both reaction raw materials.

<Reducing agent>
In the present invention, it is an essential requirement that the condensation reaction product of the aldehyde compound and the hydroxynaphthalene compound be obtained in the presence of a reducing agent.

  The reducing agent is preferably added to the reaction system in the condensation reaction before the initiation, during the condensation reaction, or at both stages, preferably before the condensation reaction. By the condensation reaction in the presence of this reducing agent, the uniform stability of the resulting condensation reaction product solution is improved, and no gelled product is produced even when stored for a long period of time. There is an advantage that it does not affect the quality of the product by preventing it from being mixed in. Furthermore, there is an advantage that the scale adhesion preventing effect of the scale preventive coating film obtained from the scale inhibitor of the present invention is improved.

  The “before the start of the condensation reaction” means the time before the step of raising the temperature of the reaction system from room temperature to a predetermined reaction temperature is completed after the preparation of the solution of both reaction raw materials and the like. . In addition, “during the condensation reaction” means that after the temperature of the reaction system reaches a predetermined reaction temperature, and the unreacted reaction raw material remains in the reaction system, the condensation reaction is not completed. Means stage.

Reducing agents include sulfites, phosphites, nitrites, reducing sugars, and thiourea dioxide.
Examples of the sulfite include ammonium sulfite, potassium sulfite, sodium sulfite, ammonium hydrogen sulfite, sodium hydrogen sulfite, sodium dithionite (Na ₂ S ₂ O ₄ ), Rongalite and the like.

  As phosphites, for example, ammonium phosphite, sodium phosphite, potassium phosphite, calcium phosphite, uranyl phosphite, cobalt phosphite, ferrous phosphite, ferric phosphite , Copper phosphite, barium phosphite, hydrazinium phosphite, ammonium hydrogen phosphite, sodium hydrogen phosphite, potassium hydrogen phosphite, potassium hydrogen phosphite, cobalt hydrogen phosphite, hydrogen phosphite Cuprous, cupric hydrogen phosphite, ferrous hydrogen phosphite, ferric hydrogen phosphite, lead hydrogen phosphite, barium hydrogen phosphite, magnesium hydrogen phosphite, hydrogen phosphite Examples include manganese and hydrazinium hydrogen phosphite.

  Examples of nitrites include ammonium nitrite, sodium nitrite, potassium nitrite, calcium nitrite, zinc nitrite, silver nitrite, cobalt potassium nitrite, sodium cobalt nitrite, strontium nitrite, cesium nitrite, cerium nitrite, Examples include cupric nitrite, nickel nitrite, barium nitrite, magnesium nitrite, lithium nitrite, and rubidium nitrite.

  The reducing saccharide is a saccharide having a free aldehyde group or a carbonyl group and exhibiting reducibility. Examples thereof include maltose, lactose, and glucose (glucose).

The sulfites, phosphites, nitrites, reducing sugars, and thiourea dioxide exemplified above can be used singly or in combination of two or more. For example, sulfites and sulfites can be used. Even when two or more reducing agents are combined, such as a combination with a phosphate, it can be used.
Of the reducing agents exemplified above, sulfites and thiourea dioxide are preferred.

  When this reducing agent is used, the amount used is usually about 0.01 to 10 parts by weight, preferably about 0.1 to 3 parts by weight, with respect to 100 parts by weight of the total of both reaction raw materials. By making the amount of reducing agent used within the above range, gelation products are not generated in the condensation reaction, and the condensation reaction products can be obtained in a uniform and stable solution state, and also prevent scale adhesion. It is possible to form an excellent scale preventive coating film.

<Condensation reaction>
The condensation reaction is carried out at room temperature to 200 ° C., preferably 30 to 150 ° C. in the presence of the reducing agent after uniformly dissolving both reaction raw materials in the solvent. The time required for the condensation reaction may be adjusted depending on the total amount of the above two reaction raw materials, but is usually 2 to 100 hours, preferably about 3 to 30 hours.

  It is preferable to use a catalyst for the condensation reaction. Examples of the catalyst include acidic catalysts such as sulfuric acid, hydrochloric acid, perchloric acid, p-toluenesulfonic acid, methanesulfonic acid, and trifluoromethanesulfonic acid; basic catalysts such as sodium hydroxide, potassium hydroxide, and ammonium hydroxide; Etc. can be used. The amount of the catalyst used is not particularly limited as long as it is an effective amount as a catalyst, but is usually about 1 to 20 parts by weight, preferably about 2 to 15 parts by weight with respect to a total of 100 parts by weight of both reaction raw materials. . The amount used can be economically advantageous and can sufficiently promote the condensation reaction.

  The pH condition of the reaction system for the condensation reaction is not particularly limited, but is usually in the range of 1 to 13, preferably 7 to 13. In addition, a pH adjuster can be added to a reaction system as needed, without restrict | limiting the kind and addition amount.

  By the condensation reaction, a condensation reaction product of the aldehyde compound and the hydroxynaphthalene compound can be obtained in a uniform solution state. Subsequently, a solvent etc. are removed from the said solution, and the condensation reaction product which is (A) component of this invention is obtained. If there is no hindrance in the preparation of the scale inhibitor, the solution may be used as it is for the preparation of the scale inhibitor of the present invention. In this case, there is an advantage that the process is simplified.

[(B) Nitrogen atom-containing polymer compound]
The scale inhibitor of the present invention is greatly characterized in that (B) a nitrogen atom-containing polymer compound is combined with the condensation reaction product of the component (A). By the combination, it becomes possible to form a scale-preventive coating film having a remarkably excellent scale-preventing effect by only one-step application, and a polymer product having no quality problem can be produced.

Examples of the nitrogen atom-containing polymer compound as component (B) include polyethyleneimine, polyacrylamide, N-vinyl-2-pyrrolidone / acrylamide copolymer, dimethyldiammylammonium chloride cyclized polymer, dimethyldiethyldiamylammonium Cyclized polymer of chloride, cyclized polymer of diallylamine hydrochloride, cyclized copolymer of dimethyldiallylammonium chloride and sulfur dioxide, polyvinyl pyridine, polyvinyl pyrrolidone, polyvinyl carbazole, polyvinyl imidazoline, polydimethylaminoethyl acrylate, poly Diethylaminoethyl acrylate and derivatives or modified products of these polymer compounds, such as partially cross-linked products, copolymers, graft copolymers, and these polymer compounds include —OH, —NH ₂ , —COOH, —SO Examples thereof include those introduced with a functional group such as ₃ H. This component (B) can be used alone or in combination of two or more.
Among these, the use of polyvinylpyrrolidone is preferable because the scale prevention effect is improved. When polyvinylpyrrolidone is used, it is effective to use a weight average molecular weight of usually about 3,000 to 5,000,000, preferably about 6,000 to 3,000,000.

  The amount of component (B) used is usually 1 to 100 parts by weight, particularly 5 to 50 parts by weight, based on 100 parts by weight of the condensation reaction product of component (A). preferable. The said range is desirable at the point that the scale adhesion prevention coating film of the uniform and sufficient thickness excellent in the scale adhesion prevention effect can be formed easily.

[(C) Inorganic colloid, alkali metal silicate]
In addition to the above components (A) and (B), the scale inhibitor of the present invention further contains at least one selected from the group consisting of (C) inorganic colloids and non-colloidal alkali metal silicates. Also good. When this component (C) is used in combination, the adsorptive power of the scale-preventing coating film to the inner wall surface of the polymerization vessel is enhanced, and there is an effect that the scale-preventing effect is improved.

  Examples of inorganic colloids include colloids of metal oxides such as aluminum, thorium, titanium, zirconium, antimony, tin, and iron; colloids of the metal hydroxides; colloids of elements such as selenium, sulfur, gold, and silver And colloids of compounds such as silica, tungstic acid, vanadium pentoxide and silver iodide. These can be used singly or in combination of two or more. Preferred among these are aluminum, titanium, antimony, tin, or iron oxides and colloids of the metal hydroxides, and colloidal silica.

  The method for producing the inorganic colloid is not particularly limited. For example, a particle colloid produced by a dispersion method or an aggregation method using water as a dispersion medium may be used. The particle size of the colloidal particles is not particularly limited, but is usually 1 to 500 nm, particularly 4 to 100 nm.

Examples of alkali metal silicates include, for example, alkali metal metasilicates such as lithium, sodium, and potassium: M ₂ SiO ₃ (the above M is an alkali metal, the same shall apply hereinafter), orthosilicate: M ₄ SiO ₄ , Disilicate: M ₂ Si ₂ O ₃ , trisilicate: M ₃ Si ₃ O ₇ , sesquisilicate: M ₄ Si ₃ O _10, etc .; solid water glass: Na ₂ O · nSiO ₂ (n is 2 Is a positive number of ~ 4). These can be used singly or in combination of two or more. Among these, solid water glass: Na ₂ O · nSiO ₂ is preferable.

  When the component (C) is used in combination, the amount used is usually 0.1 to 100 parts by weight, particularly 1 to 50 parts by weight per 100 parts by weight of the condensation reaction product of the component (A). It is preferable that

[Preparation of scale inhibitor]
In preparing the scale inhibitor, for example, the component (A) and the solution of the component (B) are mixed. The solution of the condensation reaction product obtained by the condensation reaction of the component (A) may be used as it is and mixed with the solution of the component (B). If necessary, in the mixing step, the component (C), which is an optional blending component, is also mixed together.

In order to prepare the solution of the component (B), water or a mixed solvent of water and a hydrophilic organic solvent miscible with water is used. Examples of the hydrophilic organic solvent include alcohol solvents such as methanol, ethanol and propanol; ketone solvents such as acetone and methyl ethyl ketone; ester solvents such as methyl acetate and ethyl acetate; N-methyl-2-pyrrolidone, N , N′-dimethyl-2-imidazolidone, etc., a compound represented by the above general formula (1); These can be used alone or as a mixed solvent of two or more.
Among the solvents, use of water, a mixed solvent of water and the alcoholic solvent, or a mixed solvent of water and the compound represented by the general formula (1) allows the solubility of the component (B). It is preferable from the viewpoint of good points and relatively low odor.

When using a mixed solvent of water and a hydrophilic organic solvent, the content of the hydrophilic organic solvent reduces the possibility of precipitation of compounding components due to concentration changes due to volatilization of the hydrophilic organic solvent, and ignites. In view of the dangers of toxicity, etc., and the safety in handling, it is preferable to limit the amount so as not to cause a problem. Specifically, the content is preferably 50% by weight or less in a mixed solvent with water, and more preferably 30% by weight or less.
Moreover, when preparing the solution of the said (B) component, you may add and adjust pH adjusters, such as sodium hydroxide, potassium hydroxide, and ethylenediamine, as needed.

  In addition, although the density | concentration of (B) component contained in the solution of said (B) component needs to be adjusted with the kind of (B) component used, the range of 1.0-15 weight% is preferable normally, More preferably, it is 2.0 to 10% by weight.

As described above, the scale inhibitor containing each component can be obtained as a uniform liquid, and the mixing operation itself is not particularly limited. The mixer may be a commonly used one, and for example, an apparatus such as a jacketed reactor for heating having a stirrer can be used.
The uniform liquid of the scale inhibitor of the present invention thus obtained is used as a coating solution applied to the inner wall surface of the polymerization vessel.

In addition, solid content (including component (A) and component (B). When component (C) is present, components (A) to (C) are included) contained in the coating solution, the condensate is precipitated. Since it is desirable to make it the range which does not carry out, it is desirable to make it into the range of 4 to 25 weight% normally, Preferably it is 8 to 20 weight%.
Moreover, since it is desirable to make the pH of the coating solution alkaline so that the condensate does not precipitate, it is usually 9 to 13.5, preferably 10.5 to 13.0. This pH value can be set by adjusting the amount of a pH adjusting agent such as sodium hydroxide, potassium hydroxide, or ethylenediamine as required.

[Formation of scale preventive coating]
The formation process of the scale prevention coating film using the scale inhibitor of this invention is demonstrated referring FIG. In addition, the application method of the scale inhibitor of the present invention is not particularly limited, but it is preferably applied to, for example, the inner wall surface of the polymerization vessel using water vapor as a carrier. FIG. 1 is a schematic view of an apparatus used for forming a scale preventive coating film.

<Water vapor carrier>
The water vapor used as the carrier of the coating liquid may be normal saturated water vapor or superheated water vapor, and is usually 0.196 to 3.43 MPa (G) (2 to 35 kgf / cm ² · G), particularly 0.196. Those having a pressure of ˜1.96 MPa · G (2 to 20 kgf / cm ² · G) are preferable. The temperature of the water vapor is usually 120 to 260 ° C, particularly preferably 130 to 200 ° C.

  In addition, the value of the said pressure and temperature of water vapor | steam means the value measured in the water vapor | steam supply line 6 of FIG. 1 before the time of vapor | steam mixing with a coating liquid, for example so that it may mention later.

<Application process>
Process 1. (Preheating the inner wall of the polymerization vessel with water vapor)
The temperature of the inner wall surface of the polymerization vessel is preheated to a temperature of 50 ° C. or higher, preferably 50 to 95 ° C., through hot water or the like through a jacket 2 attached to the polymerization vessel 1. An applicator ring 4 made of an annular pipe and having a downward nozzle 3a and an upward nozzle 3b is provided at the top of the polymerization vessel. Connected to the coating ring 4 is a line 5 that can integrally supply water vapor and coating liquid from the outside of the polymerization vessel 1.

  A steam supply line 6 and a coating liquid supply line 7 are connected to the line 5 via valves. If necessary, only the water vapor supplied from the application nozzles 3a and 3b of the application ring 4 through the water vapor supply line 6 and the line 5 is blown into the polymerization vessel, and the baffle ( A stirring blade (not shown) and the like can also be heated in advance. In this apparatus, water vapor is supplied from the water vapor supply device 8 through the flow meter 9 to the coating ring 4 through the lines 6 and 5.

Step 2. (Application of scale inhibitor)
Water vapor is supplied to the application ring 4, and the application liquid 11 stored in the application liquid tank 10 is supplied to the application ring 4 via the lines 7 and 5 by a pump 12 or an aspirator valve (not shown). In the figure, P is a pressure gauge. The coating solution is applied in a mist state integrated with water vapor and applied to the surface where the monomer contacts during the polymerization reaction such as the inner wall surface of the polymerization vessel, the surface of the baffle, and the surface of the stirring blade. The coating solution applied on these surfaces simultaneously with this application is dried simultaneously with application to form a scale inhibitor coating film. Therefore, no special operation for drying is necessary.

  The mixing ratio (L / G) of the water vapor (G) and the coating liquid (L) in the line 5 is usually 0.005 to 0.8, particularly 0.01 to 0.2, as a flow rate ratio (weight basis) per unit time. It is preferable to control as described above. By setting the mixing ratio within the above range, the mist in a state suitable for forming a scale-preventing coating film on the inner wall surface of the polymerization vessel can be formed.

Process 3. (Washing)
After stopping the supply of the water vapor and the coating liquid, the inside of the polymerization vessel 1 is washed with the washing water 14 stored in the water tank 13. The washing water is supplied from the nozzle 17 to the polymerization vessel through the line 16 by the pump 15. In addition, when the formation state of the coating film is good and the quality of the polymer product is not affected even if the water washing step is omitted, the water washing is not performed, and the process is simplified and the productivity is improved. Can be planned.

Through the above process, the coating amount of the scale inhibitor is formed (after drying) is generally, 0.0005~3g / m ^2, particularly preferably a 0.0005~1g / m ^2. By setting the coating amount within the above range, a coating film having a necessary and sufficient thickness can be formed on the inner wall surface of the polymerization vessel, and a good scale prevention effect can be exhibited. Furthermore, problems associated with peeling of the coating film from the inner wall surface of the polymerization vessel can be reduced.

[polymerization]
The scale inhibitor of the present invention is applied during the polymerization of a monomer having an ethylenically unsaturated double bond. Examples of this monomer include, for example, vinyl halides such as vinyl chloride; vinylidene halides such as vinylidene chloride; vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid, methacrylic acid, and esters or salts thereof. Maleic acid, fumaric acid, and esters or acid anhydrides thereof; conjugated diene monomers such as butadiene, chloroprene and isoprene; styrene; acrylonitrile; vinyl ether and the like.

  As an example in which the scale inhibitor of the present invention is particularly preferably practiced, vinyl halides or vinylidene halides such as vinyl chloride and vinylidene chloride, or monomer mixtures composed mainly of these with other monomers Examples thereof include a process for producing a polymer or copolymer of the monomer or monomer mixture by suspension polymerization or emulsion polymerization in an aqueous medium.

  Further, the scale preventive coating film formed from the scale preventive agent of the present invention is higher than the conventionally known scale preventive coating films such as α-methylstyrene, (meth) acrylic acid ester, acrylonitrile, vinyl acetate and the like. Even if it is applied to the polymerization of monomers having solubility, it exhibits high durability, so the production of polymer beads or latexes such as polystyrene, polymethyl methacrylate, polyacrylonitrile, etc., SBR, NBR, CR, IR, It can also be suitably applied to the production of synthetic rubber such as IIR (these synthetic rubbers are usually produced by emulsion polymerization) and the production of ABS resin.

  In the polymerization of one or more of these monomers, regardless of the polymerization mode such as suspension polymerization, emulsion polymerization, bulk polymerization, solution polymerization, etc., emulsifier, stabilizer, lubricant, plasticizer, pH adjuster In the presence of any additive such as a chain transfer agent, the purpose of scale prevention is effectively achieved. For example, in the suspension polymerization or emulsion polymerization of vinyl monomers, various additives are added to the polymerization system as necessary. Examples of the additive include suspension stabilizers such as partially saponified polyvinyl alcohol and methyl cellulose; anionic emulsifiers such as sodium lauryl sulfate; nonionic emulsifiers such as sorbitan monolaurate and polyoxyethylene alkyl ether; tribasic lead sulfate , Stabilizers such as calcium stearate, dibutyltin dilaurate and dioctyltin mercaptide; chain transfer agents such as trichloroethylene and mercaptans; various pH adjusters and the like. According to the application of the scale inhibitor of the present invention, even if such an additive is present in the polymerization system, scale adhesion is effectively prevented.

  Moreover, the remarkable polymer scale adhesion preventing effect of the scale inhibitor of the present invention is exhibited when any polymerization initiator is used without being affected by the type of the polymerization initiator. Specific examples of the polymerization initiator include, for example, t-butyl peroxyneodecanoate, bis (2-ethylhexyl) peroxydicarbonate, 3,5,5-trimethylhexanoyl peroxide, α-cumi Luperoxyneodecanoate, cumene hydroperoxide, cyclohexanone peroxide, t-butylperoxypivalate, bis (2-ethoxyethyl) peroxydicarbonate, dibenzoyl peroxide, diisopropylbenzene hydroperoxide, lauroyl peroxide 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, α, α'-azobisisobutyronitrile, α, α'-azobis-2,4-dimethylvaleronitrile, di-2-ethylhexyldi Peroxyisophthalate, potassium persulfate, persulfate Examples include ammonium.

  Other conditions for the polymerization may be as 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 reference to suspension polymerization, solution polymerization, and bulk polymerization as examples, but the present invention is not limited thereto.

In the case of suspension polymerization, first, water and a dispersing agent are charged into a polymerization vessel, and then a polymerization initiator is charged. Next, after the inside of the polymerization vessel is evacuated to about 0.001 to 101 kPa · G (about 0.01 to 760 mmHg), the internal pressure of the polymerization vessel is usually 49 to 2940 kPa · G (0.5 to Charge the monomer in an amount of 30 kgf / cm ² · G), and then polymerize at a reaction temperature of 30 to 150 ° C. During the polymerization, one or more of water, a dispersant and a polymerization initiator are added as necessary. The reaction temperature during the polymerization varies depending on the type of monomer to be polymerized. For example, the polymerization is performed at 30 to 80 ° C. in the case of vinyl chloride polymerization, and the polymerization at 50 to 150 ° C. in the case of styrene polymerization. I do. Polymerization is performed when the internal pressure of the polymerization vessel decreases to 0 to 686 kPa · G (0 to 7 kgf / cm ² · G), or to the inlet of cooling water that flows into and out of the cooling jacket attached to the outer periphery of the polymerization vessel. It is considered complete when the difference between the temperature and the outlet temperature is almost gone (ie when the exotherm from the polymerization reaction is gone). The amount of water, dispersing agent and initiator charged during the polymerization is usually 20 to 500 parts by weight of water, 0.01 to 30 parts by weight of the dispersing agent and 0.01 to 5 parts by weight of the polymerization initiator with respect to 100 parts by weight of the monomer. Part.

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

  In the case of bulk polymerization, the inside of the polymerization vessel is evacuated to a pressure of about 0.001 to 101 kPa · G (about 0.01 to 760 mmHg) or atmospheric pressure, and then a monomer and a polymerization initiator are charged into the polymerization vessel. And polymerization at a reaction temperature of −10 to 250 ° C. For example, in the case of polymerization of vinyl chloride, the polymerization is performed at 30 to 80 ° C., and in the case of polymerization of styrene, the polymerization is performed at 50 to 150 ° C.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.
In addition, what attached | subjected * to "Coating liquid No." etc. of Table 1 is a comparative example which does not satisfy | fill the conditions of this invention, and other than that is an Example.

  Hereinafter, “parts” means “parts by weight”. Further, the “condensate (A)” in Table 1 means a condensation reaction product of the aldehyde compound of component (A) and a hydroxynaphthalene compound. “Auxiliary agent (B)” means a nitrogen atom-containing polymer compound. “Auxiliary agent (C)” means the inorganic colloid or alkali metal silicate of component (C). (A), (B) and (C) described in Tables 1 and 2 mean each component according to the above. The same applies to the descriptions in Table 3 and Table 4.

[Preparation of condensation reaction product]
In the following preparation examples of the condensation reaction product as the component (A), the weight average molecular weight of the condensation product of the obtained product was measured as follows.
-Measurement of weight average molecular weight Polystyrene conversion weight average molecular weight was measured by gel permeation chromatography (GPC) under the following measurement conditions.

Column: Guard column
Product name: shim-pack GPC-800DP (manufactured by Shimadzu Corporation)
Analytical column
Product name: shim-pack GPC-803D, 802D (manufactured by Shimadzu Corporation)
Carrier: LiBr / DMF = 10 mmol / L
Flow rate: 1.0 mL / min
Detector: UV absorption spectrum (wavelength = 290 nm)
Temperature: 60 ° C

<Preparation example 1> Preparation of condensate No. 1 (comparative preparation example using no reducing agent)
A pressure-resistant reactor was charged with 36.0 kg (250 mol) of 1-naphthol and 180 L of 1 N NaOH aqueous solution (NaOH content 7.2 kg (180 mol)) and heated to 70 ° C. while stirring. Next, 19.75 kg (containing 1.92 wt% formaldehyde) of an aqueous solution in which formaldehyde was dissolved in the reaction mixture was added dropwise at a constant rate over 1.5 hours. Until the dropping was completed, the internal temperature of the reactor was adjusted so as not to exceed 80 ° C. The reaction mixture was then continuously stirred over 3 hours, during which time the temperature was reduced to 60 ° C. 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 the condensation reaction product (condensate No. 1).
Next, after removing the solvent of the cooled reaction mixture, the residue was washed and dried at 50 ° C. under reduced pressure. The result of measuring the weight average molecular weight of the condensate No. 1 was 2,400.

<Preparation example 2> Preparation of condensate No. 2 (aqueous solvent system, using reducing agent)
A pressure-resistant reactor was charged with 36.0 kg (250 mol) of 1-naphthol and 180 L of 1 N NaOH aqueous solution (NaOH content 7.2 kg (180 mol)) and heated to 70 ° C. while stirring. Next, 19.75 kg (containing 1.92 wt% formaldehyde) of an aqueous solution in which formaldehyde was dissolved in the reaction mixture was added dropwise at a constant rate over 1.5 hours. Immediately after the dropwise addition of the aqueous formaldehyde solution, 17.25 kg of a 20 wt% aqueous sodium nitrite solution (sodium nitrite content 50 mol) was added dropwise at a constant rate over 0.1 hour. During this time, the internal temperature of the reactor was adjusted so as not to exceed 80 ° C. The reaction mixture was then continuously stirred over 3 hours, during which time the temperature was reduced to 60 ° C. 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 the condensation reaction product (condensate No. 2).
Next, after removing the solvent of the cooled reaction mixture, the residue was washed and dried at 50 ° C. under reduced pressure. The result of measuring the weight average molecular weight of Condensate No. 2 was 2,300.

<Preparation example 3> Preparation of condensate No. 3 (organic solvent system, using reducing agent)
Condensation in the same manner as in Preparation Example 2 except that 90 kg of N-methyl-2-pyrrolidone and 90 L of 2N NaOH aqueous solution (NaOH content 7.2 kg (180 mol)) were charged instead of 180 L of 1N NaOH aqueous solution. A reaction product (condensate No. 3, weight average molecular weight 4,900) was obtained.

<Preparation Example 4> Preparation of condensate No. 4 (organic solvent system, using reducing agent)
Instead of 1-naphthol, 36.0 kg (250 mol) of 2-naphthol was used. Instead of 180 L of 1N NaOH aqueous solution, 90 kg of N-methyl-2-pyrrolidone and 90 L of 2N NaOH aqueous solution (NaOH content 7.2 kg (180 kg) In the same manner as in Preparation Example 2, except that 24.51 L of an aqueous solution in which 980 g of furfural is dissolved per liter (250 mol of furfural content) is used instead of the aqueous formaldehyde solution. A product (condensate No. 4, weight average molecular weight 4,700) was obtained.

<Preparation Example 5> Preparation of condensate No. 5 (organic solvent system, using reducing agent)
Instead of 180 L of 1 N NaOH aqueous solution, 90 kg of N, N'-dimethyl-2-imidazolidone, 90 L of 2 N NaOH aqueous solution (NaOH content 7.2 kg (180 mol)) and 2 N NaOH aqueous solution 90 L (NaOH content 7.2 kg (180 mol) )), And in place of the aqueous sodium nitrite solution, 43.53 kg of a 20% by weight aqueous sodium dithionite solution (sodium dithionite content of 50 mol) was used. Similarly, a condensation reaction product (condensate No. 5, weight average molecular weight 5,300) was obtained.

<Preparation Example 6> Preparation of condensate No. 6 (aqueous solvent system, using reducing agent)
In the same manner as in Preparation Example 2 except that 43.53 kg of a 20% by weight aqueous solution of sodium dithionite (sodium dithionite content 50 mol) was used instead of the aqueous sodium nitrite solution, the condensation reaction product ( Condensate No. 6, weight average molecular weight 5,400) was obtained.
In Table 1 below, condensate No. 1 to condensate No. 6 obtained in Preparation Example 1 to Preparation Example 6 are sequentially described as CP1 to CP6.

[Preparation of coating solution]
Preparation of Coating Liquid Nos. 101 to 119 Condensate (A), auxiliary agent (B) and auxiliary agent (C) shown in Table 1 below are shown in Table 1 below (A) / (B) / (C ) Weight ratio. In addition, the auxiliary agent (B) and auxiliary agent (C) which were used are as having shown concretely in Tables 3-4 as below-mentioned.

  Furthermore, all the components were mixed and dissolved using a solvent having the composition shown in Table 2. Upon dissolution, the total concentration and pH of components (A) to (C) were adjusted as shown in Table 2. Thus, coating solutions No. 101 to No. 119 in which each component was uniformly dissolved were obtained.

However, coating solution No. 102 ^* and coating solution No. 103 ^* are comparative examples using CP1 prepared without using a reducing agent as in Preparation Example 2 above. The coating solution No. 103 ^* corresponds to the coating solution using polyvinyl pyrrolidone and colloidal silica used in Experiment No. 112 described in JP-A-6-206909. The polyvinylpyrrolidone and colloidal silica are listed in Tables 3 and 4.

＊：比較例

*: Comparative example

＊：比較例

*: Comparative example

<Auxiliary agent (B)>
A to f abbreviated as auxiliary agents (B) described in Table 1 are those described in Table 3 below. (The auxiliaries (B) a to d described in Table 3 below are those manufactured by IPS Japan.)

<Auxiliary agent (C)>
G to m abbreviated as auxiliary agents (C) listed in Table 1 are those listed in Table 4 below.

Examples and Comparative Examples The following experiments were conducted using the polymerization apparatus shown in FIG. 2 that are the same as those in FIG. 1 are denoted by the same reference numerals.

In FIG. 2, a SUS 316 L stainless steel polymerization vessel 1 having an internal volume of 2 m ³ has a stirring device 19 (stirring motor not shown) having a stirring blade 18, a heating / cooling jacket 2, a manhole 20, a baffle 21, and Other equipment (not shown) usually provided in other polymerization equipment for vinyl chloride polymerization is provided. A line 22 connected to the upper portion of the polymerization vessel 1 is a raw material charging line. As shown in the drawing, a vinyl chloride monomer (hereinafter referred to as “VCM”) charging line 22a, a catalyst solution charging line 22b, as shown in FIG. Further, branch lines such as a suspension agent charging line 22c and a pure water charging line 22d are connected. Valves V1, V2, V3, V4 and V5 are provided at the positions shown in the drawing line 22 and the lines 22a to 22d.

  A line 23 connected to the upper portion of the polymerization vessel 1 is provided for exhausting the polymerization vessel 1 and collecting VCM. The line 23 is led to a gas holder 25 through a line 24 branched from the line 23. A VCM recovery line 26 is led out from the gas holder 25, and a line 27 led out from the gas holder 25 is connected to the line 23 and is used for a pressure equalizing operation described later. These lines 23, 24, 26 and 27 are provided with valves V6, V7, V8, V9, V10, V11, V12 and V13 at the positions shown in the figure. The line 24 branches to a line 24a provided with a vacuum pump 28 used for exhausting the polymerization vessel 1, recovery of VCM, and the like, and a line 24b not provided with such a pump, and then once again. Two lines are connected to the gas holder 25.

  Further, a washing water supply line 16 is connected to the upper portion of the polymerization vessel 1 in order to perform washing in the polymerization vessel. The line 16 is provided with a valve 14 at the position shown in the figure, and a nozzle 17 is provided at the tip led into the polymerization vessel. Furthermore, a coating liquid supply line 7 is connected to the upper portion of the polymerization vessel 1 via a valve V17 as shown in the figure. Further, a steam supply line 6 is connected to the line 5 via a valve. An application ring 4 provided with application nozzles 3a and 3b is provided at the tip of the line 5 in the polymerization vessel. These lines are provided with valves V15 and V16 at the positions shown in the figure. The steam supply line 6 is provided with a valve V18 at the illustrated position. A line 29 is connected to the bottom of the polymerization vessel 1, which is divided into a line 29 a for guiding the polymer slurry to the slurry tank via the filter 30 and a line 29 b for discharging the coating liquid and the washing water to the waste water tank. . Valves V19, V20 and V21 are provided at the positions shown in the lines 29, 29a and 29b, respectively.

  In Experiment No. 101 to Experiment No. 119, polymerization of vinyl chloride was repeatedly performed as described below using the coating solution No. 101 to the coating solution No. 119, respectively. In addition, although drying itself after apply | coating a coating liquid is required, the special operation for that is usually unnecessary, and a drying operation (process) is not performed also in a present Example.

(1) Pretreatment in the polymerization vessel A scale preventive coating film is formed on the inner wall of the polymerization vessel of the polymerization apparatus shown in Fig. 2 by the following method. All valves are initially closed.
In the pretreatment step, hot water is passed through the jacket 2 to apply the coating solution without preheating the inner wall surface of the polymerization vessel 1. As a result, the process can be simplified.

Valves V18, V21, V19, V15 and V16 are opened, and water vapor of 392 kPa · G (4 kgf / cm ² · G) (143 ° C.) is blown into the polymerization vessel at a flow rate of 4 kg / min for 1 minute to form a polymerization vessel After preheating the inside, the valve V17 is opened and a coating solution containing a scale inhibitor is supplied through the line 7 at a flow rate of 0.2 kg / min for 1 minute. As a result, the coating liquid is integrated with the water vapor in the line 5. The water vapor is used as a carrier to apply a scale adhesion preventing agent to the inner wall surface of the polymerization vessel and simultaneously dry. At this time, the mixing ratio (L / G) of the water vapor (G) and the coating liquid (L) is 0.05 as a flow rate ratio (weight basis). Thereafter, the valves V18, V21, V19, V15, V16 and V17 are closed.
Valves V14, V19, V21, V6, V7 and V10 are opened, the inside of the polymerization vessel is washed with water for 1 minute, and the water after washing is discharged into a waste water tank M. Thereafter, the valves V14, V19 and V21 are closed.

(2) Preparation Valves V1, V2 and V3 are opened, 200 parts of pure water, 0.020 part of partially saponified polyvinyl alcohol and 2-hydroxypropylmethylcellulose (trade name: Metroles, Shin-Etsu Chemical Co., Ltd., methoxyl group substitution degree: 1.9, 2-hydroxypropoxyl group substitution degree: 0.25) 0.026 part is charged into the polymerization vessel 1. Thereafter, the valves V1, V2, V3, V6, V7 and V10 are closed.

  Next, the valves V1 and V5 are opened, 100 parts of VCM are charged, and the valve V5 is closed. Next, while stirring the charged raw materials, the valve V4 is opened, 0.03 part of t-butylperoxyneodecanoate is charged, and the valves V1 and V4 are closed.

(3) Polymerization While stirring the charged raw materials, hot water was passed through jacket 2 to raise the temperature, and when the internal temperature reached 66 ° C, cooling water flow to jacket 2 was started. Polymerization is performed while maintaining the internal temperature at 66 ° C. The polymerization is completed when the pressure in the polymerization vessel is reduced to 490 kPa · G (5 kgf / cm ² · G).

(4) Exhaust gas Valves V6, V8, V12, and V9 are opened, and the unreacted VCM is exhausted to the gas holder 25 until the internal pressure of the polymerization reactor reaches almost atmospheric pressure (101 kPa · G). Thereafter, the valves V12, V8 and V9 are closed. The valves V11 and V10 are opened and the VCM recovered in the gas holder 25 is sent to the VCM recovery device via the line 26, and then the valves V11 and V10 are closed.

(5) Pressure equalization Valves V7 and V10 are opened, and the internal pressure of the polymerization vessel 1 and the internal pressure of the gas holder 25 are made equal.

(6) Slurry extraction Valves V19 and V20 are opened, and the polymer slurry is extracted from the polymerization vessel into the slurry tank through the filter 30. The filter 30 is in the form of a wire mesh having a mesh size of 5 to 7 (mesh opening is about 3 to 4 mm). When the polymer slurry contains a scale peeled off from the inner wall surface of the polymerization vessel, the polymer slurry is collected by the filter 30.
The polymer slurry withdrawn to a slurry tank (not shown) is then dehydrated and dried to become a vinyl chloride polymer product. After extracting the polymer slurry, the valve V20 is closed.

(7) First water washing in the polymerization vessel Open the valve 21. Next, the valve V14 is opened and the inside of the polymerization vessel 1 is washed with water for 5 minutes, and the washing water is sent to the waste water tank through the filter 30. During the washing in the polymerization vessel, hot water is passed through the jacket 2 to keep the temperature of the polymerization vessel wall at 70 ° C. When the scale is separated from the inner wall surface of the polymerization vessel, particularly near the gas-liquid interface, the stirring blade, the baffle head, the support, and the like at the time of washing with water, it is collected by the filter 30.
Thereafter, the valves V14, V19, V21, V6, V7 and V10 are closed.

(8) Water vapor application and simultaneous drying Stop hot water flow to the jacket 2. Open valves V18, V21, V19, V15, V16 and V17, with a flow rate of 240 kg / Hr, 392 kPa · G (4 kgf / cm ² · G) (143 ° C), and a flow rate scale of 0.2 L / min. A coating solution containing an inhibitor is supplied for 1 minute via line 5 to perform water vapor coating and simultaneous drying. Thereafter, the valves V18, V21, V19, V15, V16 and V17 are closed.

(9) Second water washing in polymerization vessel Valves V14, V19 and V21 are opened, the inside of the polymerization vessel 1 is washed with water for 1 minute, and the water after washing is discharged into a waste water tank. Thereafter, the valves V14, V19 and V21 are closed.
The operations from the above (2) charging step to (9) the second water washing step in the polymerization vessel were regarded as one batch, and the polymerization of VCM was repeated for the total number of batches shown in Table 5 in each experiment.

<Evaluation method>
・ Measurement of polymer scale adhesion amount In each experiment, after the final batch (for example, 200th batch when polymerization was carried out in total), the polymer scale adhesion amount in the liquid phase part of the polymerization vessel, the stirring blade and The amount of polymer scale deposited near the baffle surface and the interface between the gas phase part and the liquid phase part was determined by the following method.
The scale adhering to an area of 10 cm × 10 cm on each target surface was completely scraped off with a spatula as far as it can be confirmed with the naked eye, and weighed with a balance. By multiplying the measured value by 100, the amount of scale adhered per 1 m ² (g) was determined. The results are shown in Table 5.

・ Measurement of the amount of filter scale collected In each experiment, the scale peeled off from the inner wall surface of the polymerizer collected by the filter 30 was separated after the second water washing step in the polymerization vessel and before the charging step in each batch. After collecting and drying, the weight (g) was measured. Table 5 shows the total weight (g) corresponding to the total number of batches described in Table 5 of each experiment.

-Measurement of fish eye The fish eye (number) when the polymer obtained after completion of the final batch in each experiment was molded into a sheet was measured by the following method. The results are shown in Table 6.
100 parts of a polymer, 50 parts of dioctyl phthalate, 1 part of dibutyltin dilaurate, 1 part of cetyl alcohol, 0.25 part of titanium oxide and 0.05 part of carbon black were kneaded at 150 ° C. for 7 minutes using a 6 inch roll, and the thickness was 0.2. Molded into mm sheets. The number of fish eyes contained 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 anti-initial colorability when the polymer was molded into a sheet, the lightness index (L value) was measured by the following method. The results are shown in Table 6.
100 parts of the resulting polymer, 1 part of dibutyltin laurate stabilizer (trade name: TS-101, manufactured by Akishima Chemical Co., Ltd.), cadmium organic composite stabilizer (trade name: C-100J, manufactured by Katsuta Chemical Co., Ltd.) ) A mixture of 0.5 part and 50 parts of dioctyl phthalate as a plasticizer was kneaded at 150 ° C. for 5 minutes using a two-roll mill, and then formed into a sheet having a thickness of 0.8 mm. The obtained sheet was cut into 4 cm × 4 cm, and the cut pieces were put into a 4 cm × 4 cm × 1.5 cm formwork, then preheated at 160 ° C. for 5 minutes, and then 2.84 to 3.04 MPa (29 to 31). A sample for measurement was produced by press molding under a pressure of kgf / cm ² ) for 5 minutes. The brightness index L of this sample was determined as follows.

  First, in accordance with the provisions of JIS Z 8722, using standard light C and a photoelectric colorimeter (trade name: Z-1001 DP type colorimetric color difference meter, manufactured by Nippon Denshoku Industries Co., Ltd.), the stimulus value direct reading method is used to perform the XYZ color specification. The system stimulation value Y was determined. Here, the condition d described in Section 4.3.1 of JIS Z 8722 was adopted as the geometric condition for illumination and light reception.

Next, the obtained stimulus value Y is used as the color difference formula of the Hunter specified in JIS Z 8730 (1980):
L = 10Y ^1/2
And the L value was calculated. The results are shown in Table 6. In addition, it means that whiteness is so high that an L value is large, ie, anti-initial color property is favorable.

Measurement of colored particles A mixture of 100 parts of the polymer obtained after the final batch in each experiment, 2 parts of TVS N-2000E (trade name, manufactured by Nitto Kasei Co., Ltd.) as a stabilizer, and 20 parts of dioctyl phthalate as a plasticizer After sufficiently kneading, it was put into a 160mm x 130mm x 3mm mold and pressure molded at a temperature of 175 ° C at a pressure of 3.43 MPa (35 kgf / cm ² ) to prepare a measurement sample. . About this sample, the number of colored particles was measured visually. The results are shown in Table 6.

*：比較例

*: Comparative example

*：比較例

*: Comparative example

[Evaluation]
As is clear from the results shown in Table 5, a scale preventive coating film is formed on the inner wall surface of the polymerization vessel by one-step coating using the scale inhibitor containing the components (A) and (B) of the present invention. In the experiments No. 101, No. 104 to No. 119, even when the polymerization batch of as many as 200 batches was repeated under the high temperature polymerization reaction condition of 66 ° C., in particular, near the gas-liquid interface in the polymerization vessel, the stirring blade It can be seen that the amount of scale attached to the part and the baffle part is remarkably small.

  The amount of scale collected by the filter 30 corresponds to the amount of scale peeled or deposited on the inner wall surface of the polymerization vessel. Even when the amount of scale collected in the filter 30 is seen, it can be seen that the scale adhesion preventing effect of the scale inhibitor of the present invention on the inner wall surface of the polymerization vessel is remarkably excellent. Also, from the results shown in Table 6, when the scale inhibitor of the present invention is used, the amount of colored particles which are considered to be caused by peeling of the fish eye and the scale-preventing coating film is small. It can be seen that a polymer product having no problem in quality such as initial colorability is obtained.

In contrast, the comparative example using coating solution No. 102 ^* and coating solution No. 103 ^* containing a condensate of an aldehyde compound and a hydroxynaphthalene compound obtained without using a reducing agent is a scale. The adhesion preventing effect was poor, and the quality of the resulting polymer product was clearly inferior.

It is the figure which showed the outline of the apparatus used for scale prevention coating film formation using the scale inhibitor of this invention. It is the figure which showed the outline of the polymerization apparatus used in the Example in order to implement the polymerization method using the scale inhibitor of this invention.

Explanation of symbols

1. Polymerizer 1. Jacket 4. Application ring 6. 6. Steam supply line Coating liquid supply line 16. Wash water supply line 18. Stirring blade 21. Baffle 22. Raw material supply line 23. Exhaust and monomer recovery line 25. Gas holder 30. filter

Claims (7)

  (A) a condensation reaction product obtained by reacting an aldehyde compound with a hydroxynaphthalene compound in the presence of a reducing agent, and (B) an ethylenic double bond containing a nitrogen atom-containing polymer compound Polymer scale adhesion inhibitor for monomer polymerization. The polymer scale adhesion preventing agent according to claim 1, wherein the condensation reaction product of the component (A) is represented by the following general formula (1):

(1)
Wherein R ¹ is an alkyl group having 1 to 3 carbon atoms, X is a methylene group (—CH ₂ —) or a formula: —NR ² — (R ² is an alkyl group having 1 to 3 carbon atoms) Is a divalent group represented by
A polymer scale adhesion preventing agent obtained by a condensation reaction in the presence of an organic solvent containing a compound represented by the formula:   3. The polymer scale adhesion preventing agent according to claim 1 or 2, wherein the condensation reaction product of the component (A) is added to the reaction system before the start of the condensation reaction, during the condensation reaction, or at both stages. Polymer scale adhesion preventive agent obtained by adding   The polymer scale adhesion preventing agent according to any one of claims 1 to 3, further comprising (C) at least one selected from the group consisting of inorganic colloids and non-colloidal alkali metal silicates. , Polymer scale adhesion inhibitor.   The polymer scale adhesion preventing agent according to any one of claims 1 to 4, further comprising a solvent and in a liquid state, wherein the total content of solids is 4 to 25% by weight. Anti-adhesive agent.   A monomer having an ethylenically unsaturated double bond is polymerized in a polymerization vessel having an inner wall surface and a coating film having a scale-inhibiting property at a portion in contact with the monomer during polymerization. A method for producing a polymer, wherein the scale-preventing coating film comprises the polymer scale adhesion preventing agent according to any one of claims 1 to 4.   It is a manufacturing method which concerns on Claim 6, Comprising: The said scale prevention coating film apply | coats the coating liquid of the polymer scale adhesion prevention agent of any one of Claims 1-4 using water vapor | steam as a carrier. The manufacturing method which is formed by this.

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