JP2006282825A - Method for preventing attachment of polymer, method for treating reactor and method for producing vinylic polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preventing attachment of polymer in good persistence by a simple operation completely without using an organic solvent in the polymerization of a vinylic monomer using water as a medium. <P>SOLUTION: The method for preventing the attachment of the polymer involves coating the inner wall surface of the polymerization reactor with a condensate of a phenolic compound with an aldehyde compound in a form of an aqueous solution of a volatile amine before polymerization of the vinylic monomer in the reactor by using the water as the medium, and removing the water and the volatile amine by drying. The condensate of the phenolic compound with the aldehyde compound is preferably at least one kind selected from a pyrogallol/benzaldehyde condensate, a pyrogallol/formaldehyde condensate, a pyrogallol/formaldehyde/resorcinol condensate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for preventing adhesion of a polymer, and more specifically, relates to a method for preventing adhesion of a polymer produced when a vinyl monomer using water as a medium is polymerized. Furthermore, the processing method of a reactor and the manufacturing method of a vinyl polymer are also this invention.

A polymerization adhesion inhibitor, which is a condensate of a phenolic compound and an aldehyde compound, is dissolved in a polar organic solvent such as methanol, ethanol, acetone, tetrahydrofuran, dimethylformamide, toluene, etc., applied to the inner wall of the polymerization reactor, etc. and dried. ing. However, the use of an organic solvent has problems such as explosion during application, fire hazard, exposure of the worker to the organic solvent, and adverse environmental effects such as air pollution due to diffusion into the atmosphere.
Japanese Patent Publication No. 57-502169 discloses a method of applying a condensate of resorcinol and acetaldehyde or benzaldehyde to an inner surface of a polymerization reactor wall in an aqueous ammonium salt solution. However, after spraying on the inner wall of the polymerization reactor and washing with water to polymerize the vinyl monomer, it is water-soluble because it is an ammonium salt, and it will flow out into the aqueous medium during polymerization, and a continuous polymerization adhesion preventing effect cannot be obtained. There was a drawback. As a method for solving this problem, as a method for obtaining a continuous polymerization adhesion preventing effect without flowing into the aqueous medium during polymerization, JP-A-11-217402 discloses a method for dissolving an adhesion inhibitor in an alkaline aqueous solution. An anti-adhesive agent method is disclosed in which a vinyl monomer is polymerized after being applied to the inner surface of a polymerization reactor or the like, dried and then treated with an acidic compound aqueous solution. In this method, there has been a problem that a complicated operation must be performed in order to reduce the water solubility of the coating film after applying and drying an alkaline aqueous solution.
JP-T57-502169 Japanese Patent Laid-Open No. 11-217402

  An object of the present invention is to provide a method for preventing the adhesion of a polymer having even better durability without using an organic solvent at all in a polymerization of a vinyl monomer using water as a medium and by a simple operation. is there.

  As a result of diligent studies to solve the above problems, the present inventors have dissolved a polymer adhesion inhibitor having a hydroxyl group in an aqueous volatile amine solution and applied it to the inner wall surface of the polymerization reactor. By removing the amine, it was found that the coating film became insoluble in water without increasing the neutralization treatment with an acidic compound for reducing the water solubility used in the conventional method, and the sustainability increased. It came to complete. That is, the gist of the present invention resides in the following (1) to (5).

(1) Before polymerizing a vinyl monomer in a reactor using water as a medium, a condensate of a phenol compound and an aldehyde compound is applied to the inner wall surface of the polymerization reactor in the form of a volatile amine aqueous solution and dried. A method for preventing adhesion of a polymer to remove water and volatile amines.
(2) The above characterized in that the condensate of a phenolic compound and an aldehyde compound is selected from at least one condensate of pyrogallol / benzaldehyde condensate, pyrogallol / formalin condensate, pyrogallol / formalin / resorcinol condensate ( The method for preventing adhesion of a polymer as described in 1).
(3) In the above (1) or (2), the polymerization of the vinyl monomer using water as a medium is a polymerization method selected from suspension polymerization, microsuspension polymerization method, and emulsion polymerization. The method for preventing adhesion of the polymer as described.
(4) After applying a condensation product of a phenolic compound and an aldehyde compound on the inner wall surface of the polymerization reactor in the form of a volatile amine aqueous solution, removing water and volatile amine by drying, and preventing adhesion of the polymerized product A method for producing a vinyl polymer, wherein a vinyl monomer is polymerized in a reactor using water as a medium.
(5) A vinyl monomer polymerization reactor in which a condensate of a phenolic compound and an aldehyde compound is applied to the inner wall of the polymerization reactor in the form of a volatile amine aqueous solution, and water and volatile amine are removed by drying. Processing method

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for preventing the adhesion of a polymer having even better durability without using an organic solvent at all and in a simple operation in the polymerization of a vinyl monomer using water as a medium.

  The present invention relates to a method for preventing adhesion of a polymer to a reactor when a vinyl monomer using water as a medium is polymerized in the reactor. In the method for preventing adhesion of a polymer of the present invention, before a vinyl monomer containing water as a medium is polymerized in a reactor, a condensate of a phenol compound and an aldehyde compound is polymerized in the form of a volatile amine aqueous solution in advance. It is applied to the inner wall surface of the reactor and is characterized by removing volatile amine and water by drying.

<Condensate of phenolic compound and aldehyde compound>
The “condensation product of a phenolic compound and an aldehyde compound” in the present invention is a polymerization adhesion preventing component, and may be hereinafter referred to as “polymerization adhesion preventing agent”.
Examples of the phenolic compound in the present invention include resorcinol, catechol, hydroquinone, pyrogallol, phloroglucin and the like, and pyrogallol is preferable because it has a large number of phenol groups having an easy condensation reaction and a polymerization inhibiting effect. Examples of the aldehyde compound include formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, o-tolualdehyde, m-tolualdehyde, p-tolualdehyde, α-naphthaldehyde, β-naphthaldehyde and the like. Formaldehyde is preferred because of condensation reactivity and ease of handling.

  As a condensate of a phenolic compound and an aldehyde compound, each one kind of condensate of the said phenolic compound and an aldehyde compound may be sufficient, and multiple types of condensate may be sufficient. For example, these condensates can be obtained by subjecting a phenolic compound and an aldehyde compound to a condensation reaction of a phenolic compound and an aldehyde compound using an acidic or basic catalyst. As a condensate of a phenolic compound and an aldehyde compound, a novolak is produced by using an acidic catalyst, and a resol is produced by using a basic catalyst. Examples of the condensate of the phenolic compound and the aldehyde compound include pyrogallol / benzaldehyde condensate, pyrogallol / formalin condensate, pyrogallol / formalin / resorcinol condensate, etc. from the viewpoint of ammonia solubility and workability, and among them pyrogallol / benzaldehyde. Condensates are preferred. These condensates may be used alone or in combination of two or more.

<Volatile amine aqueous solution>
As the volatile amine in the present invention, ammonia, primary amine, secondary amine, tertiary amine can be used. Ammonia is preferable from the viewpoint of high volatility at low temperature, economy, and easy availability. Hereinafter, ammonia will be described as an example, but when other volatile amines are used, the ammonia may be replaced with other volatile amines.

  In the case of an aqueous ammonia solution, a generally available 0.005 to 5N aqueous ammonia solution can be used. Alternatively, ammonia gas may be dissolved in an aqueous suspension of a condensate of a phenolic compound and an aldehyde compound by bubbling or the like. That is, in the present invention, “applying a condensate of a phenolic compound and an aldehyde compound to the inner wall surface of the polymerization reactor in the form of a volatile amine (ammonia) aqueous solution” means (I) a condensate of a phenolic compound and an aldehyde compound. When dissolved in a volatile amine (ammonia) aqueous solution and applied to the inner wall surface of the polymerization reactor, (2) the condensation product of the phenolic compound and the aldehyde compound is suspended in water and then volatilized into the aqueous suspension. This includes both cases where a soluble amine (ammonia) is dissolved to form a volatile amine (ammonia) aqueous solution of a condensate of a phenolic compound and an aldehyde compound, and this is applied to the inner wall surface of the polymerization reactor.

  In the present invention, “the condensate of phenolic compound and aldehyde compound is applied to the inner wall surface of the polymerization reactor in the form of a volatile amine (ammonia) aqueous solution” means, in other words, “condensation of phenolic compound and aldehyde compound”. "Applying the volatile amine (ammonia) aqueous solution of the product to the inner wall surface of the polymerization reactor" and "the volatile amine (ammonia) aqueous solution of the condensate of phenolic compound and aldehyde compound" The concentration of the condensate with the aldehyde compound is generally 0.05% to 20% by weight, preferably 0.1% to 10% by weight. If the condensate concentration is too low, a large amount of volatile amine (ammonia) and water must be removed, which is economically disadvantageous. If it is too high, the amount of coating on the inner wall surface of the polymerization reactor is increased and wasted.

<Application method>
In the present invention, the volatile amine aqueous solution of the condensate of the phenolic compound and the aldehyde compound obtained above is applied to the inner wall surface of the polymerization reactor. The coating method may be a known method such as brush or spray. Is possible. Next, the inner wall surface of the applied polymerization reactor is dried to evaporate and remove moisture and volatile amines. The degree of removal of water and volatile amine is usually 90% or more, preferably 95% or more. Ideally 100% removal, but about 10% may remain. When moisture and volatile amines remain, the polymerization adhesion inhibitor of the present invention cannot sufficiently adhere and may be peeled off by a polymerization solvent or the like. The drying temperature is not particularly limited as long as it is a temperature at which water and volatile amine can be removed to the extent described above, but is usually 40 ° C to 200 ° C, preferably 50 ° C to 150 ° C, and more preferably 60 ° C to 130 ° C.

  If the drying temperature is too low, it takes time to dry, resulting in poor economic efficiency. On the other hand, if it is too high, the anti-adhesive agent will be thermally deteriorated and a sufficient effect of preventing polymerization adhesion cannot be obtained. In order to accelerate drying, a gas such as air or nitrogen may be blown. Moreover, you may apply | coat a coating agent there, heating the inner wall surface etc. of a polymerization reactor to this drying temperature previously. From the aspect of shortening the coating and drying time, it is preferable to apply to the inner wall surface of the polymerization reactor heated in advance.

  The drying time is not particularly limited as long as it is a temperature at which water and volatile amine can be removed to the extent described above, but is usually 0.5 to 10 hours, preferably 1 to 5 hours. If the drying time is too short (that is, the drying is insufficient), moisture and volatile amines remain, so that they may be peeled off by an aqueous solvent during polymerization. On the other hand, if the length is too long, the pretreatment time for polymerization becomes long, so the economic efficiency is deteriorated.

  A surfactant may be added to improve the wettability between the coated surface and the aqueous coating solution. The surfactant may be added directly to the volatile amine aqueous solution of the condensate of the phenolic compound and the aldehyde compound. If necessary, the surfactant is applied to the reactor wall surface in advance. You may apply | coat the volatile amine aqueous solution of the condensate of an aldehyde compound. As the surfactant, there are known ionic or nonionic surfactants. For example, there are known surfactants such as sodium alkylbenzene sulfonate, sodium naphthalene sulfonate, alkyl phenyl ether, and partially saponified polyvinyl acetate. These may be used alone or in combination of two or more. Considering the polymerization stability of the vinyl monomer, it is preferable to use the same surfactant that is used particularly when the vinyl monomer is polymerized using water as a medium. The amount used may be 0.011 to 10 parts by weight per 100 parts by weight of the polymerization adhesion inhibitor. If the amount of the surfactant added is too small, the wettability improving effect cannot be obtained. If the amount is too large, the hydrophilicity of the remaining surfactant may be peeled off during the polymerization reaction.

<Coating amount>
The coating amount of volatile amine aqueous solution in the present invention is usually 0.05-5 g / m ² with a polymer in terms of per coating area, is an amount that preferably a 0.05 to 3 g / m ^2. If the coating amount is too small, a sufficient polymerization adhesion preventing effect cannot be obtained. If it is too much, no further effect can be obtained and it is economically wasteful.

<Anti-adhesive agent facilitator>
In the present invention, a known metal compound used for the purpose of promoting the prevention of polymerization adhesion may be used in combination with a volatile amine aqueous solution of a condensate of a phenolic compound and an aldehyde compound. Examples of the metal compound include known substances such as oxides such as aluminum, iron, silicon, nickel, titanium, and tin, hydroxides, chlorides, and carbonates. The amount used may be 10 to 100% by weight with respect to the polymerization adhesion inhibitor.

<Inside of polymerization reactor>
The inner wall surface of the polymerization reactor refers to the inner wall surface of the polymerization reactor, the baffle plate attached to the polymerization reactor, the stirring blade, the charging pipe, the recovery pipe, the reflux pipe, and the place where polymerization adhesion is generated. In the invention, it is not necessary to apply to all of these, and it may be applied to a place where it is desired to prevent polymerization adhesion. The present invention is used as a polymerization adhesion preventing agent in vinyl monomer polymerization using water as a medium. The monomer to be polymerized is not particularly limited, but the adhesion preventing effect is great for vinyl monomers. Examples of the vinyl monomers include vinyl chloride, styrene, acrylonitrile, alkyl (meth) acrylates such as methyl methacrylate and butyl acrylate, and vinyl acetate known vinyl monomers such as vinyl chloride, styrene, Alkyl (meth) acrylates, particularly preferably vinyl chloride and styrene. These include both homopolymerization with one type of monomer or copolymerization with a combination of two or more types of monomers. In addition, the vinyl monomer polymerization using water as a medium shown in the present invention can be a suspension polymerization method, a micro suspension polymerization method in which the particle diameter obtained by the suspension polymerization method is further reduced, an emulsion polymerization method, or the like. .

<Suspension polymerization method>
The suspension polymerization method is a method of performing polymerization while keeping oil droplets of about 50 to 3000 μm, in which an oil-soluble initiator is dissolved in the vinyl monomer by stirring, in water stably. A suspension stabilizer can be added to water to stabilize the vinyl monomer in suspension. For example, starch, alkyl cellulose, hydroxyalkyl cellulose, methyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, partially saponified polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, gelatin, vinyl acetate-maleic anhydride copolymer, styrene-maleic anhydride copolymer Examples thereof include water-soluble polymer colloids such as coalescence or powders of poorly water-soluble inorganic salts such as magnesium oxide, calcium carbonate, magnesium carbonate, calcium pyrophosphate, magnesium pyrophosphate, tricalcium phosphate, and hydroxyapatite. In particular, in the case of using a poorly water-soluble inorganic salt, an anionic surfactant (for example, todecylbenzene) of 10 ppm / water to 2% / water is insufficient because it alone has poor affinity with the above-mentioned vinyl monomer oil droplets. Sulfonic acid soda, α-olefin sulfonic acid soda, etc.) can be used together as a suspension stabilizing aid. The addition amount of these suspension stabilizers is usually 0.01 to 3 parts by weight with respect to 100 parts by weight of the charged monomer.

  Examples of the oil-soluble initiator include lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, t-butyl peroxypivalate, t-butyl peroxyneodecanate, diisopropyl peroxydicarbonate, di-2- Organic peroxides such as ethylhexyl peroxydicarbonate and acetylcyclohexylsulfonyl peroxide; and azo compounds such as α, α′-azobisisobutyronitrile and α, α′-azobis-2,4-dimethylvaleronitrile These 1 type can be used individually or in combination of 2 or more types. The addition amount of these oil-soluble initiators is about 0.01 to 5% by weight with respect to the vinyl monomer.

<Micro suspension polymerization method>
The micro suspension polymerization method is a subordinate concept of the above general suspension polymerization method, and is a suspension polymerization method used to obtain a polymer having an average particle size of less than 50 μm. The suspension stabilizer used in the suspension polymerization is added to water, and the oil-soluble initiator is dissolved to the target average particle size to polymerize the vinyl monomer. For example, a mechanical shearing device such as a high-pressure homogenizer, a high-speed pump, a colloid mill, or an ultrasonic horn can be used as a method for reducing the particle size to the target average particle size. As the oil-soluble initiator and the suspension stabilizer, those described in the above suspension polymerization method can be used.

<Emulsion polymerization method>
In the emulsion polymerization method, the monomer is dispersed as particles of micron or less in an aqueous medium that hardly dissolves the vinyl monomer, and a small amount of a stabilizer such as a surfactant is added to dissolve the monomer in water. This is a method in which polymerization is carried out by adding a polymerizable polymerization initiator. Further, a soap-free polymerization method without using an emulsifier can also be used. As an emulsifier to be used, various anionic, cationic and nonionic emulsifiers, and further a polymer emulsifier can be used. As the water-soluble polymerization initiator, inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide can be used. These inorganic peroxides can be used as a redox initiator in combination with a reducing agent. Various known methods can be used for supplying the vinyl monomer in the emulsion polymerization. For example, various methods such as a batch charging method, a monomer addition method, and an emulsion addition method can be used. A seed polymerization method or a power feed polymerization method in which the composition of the vinyl monomer to be added is sequentially changed can also be used.

Examples of the present invention and comparative examples are illustrated below, but these do not limit the present invention.
Reference Example: Condensate of phenolic compound and aldehyde compound A pyrogallol / benzaldehyde condensate was obtained using the same method as in Example 1 of JP-A-55-54317. Specifically, 387.5 g of distilled water was put into an 800 ml glass separable flask equipped with a stirrer with a half moon blade, a cooling pipe and a nitrogen introduction pipe, and stirring at 200 rpm and introduction of nitrogen at 50 ml / min were started. Further, 95.6 g of pyrogallol (special grade manufactured by Kishida Chemical) was added. After confirming that pyrogallol was dissolved, 138.9 g of benzaldehyde (85% manufactured by Kishida Chemical Co., Ltd.) was added dropwise over 30 minutes.

The reactor was immersed in an oil bath at 120 ° C., and temperature increase was started. The reaction was started for 4 hours, starting when the internal temperature reached 95 ° C. The reactor was taken out from the oil bath, cooled to room temperature, stirring was stopped, insoluble matter was filtered, and dried under reduced pressure at 50 ° C. for 5 hours to obtain a pyrogallol / benzaldehyde condensate.
Analysis results: As a result of measurement by infrared spectroscopy using the KBr tablet method, absorption was observed at 763,700 cm ⁻¹ derived from 3460,911 and benzene nucleus 1 substitution, respectively.

Example 1
5 g of the pyrogallol / benzaldehyde condensate obtained in the above Reference Example was pulverized with a coffee mill and then dissolved in 100 mL of a 0.1 N aqueous ammonia solution. An aqueous ammonia solution of the pyrogallol / benzaldehyde condensate was spray-coated on the inner wall surface of the 3 L polymerization reactor and dried at 70 ° C. for 60 minutes. From the spray amount, the coating amount of pyrogallol / benzaldehyde condensate was 1 g / m ² .

Continuous 10 batch polymerization was carried out by the suspension polymerization method of styrene shown below. Table 1 shows the effect of preventing polymerization adhesion after each batch.
Comparative Example 1
Using the same pyrogallol / benzaldehyde condensate as in Example 1, after pulverizing 5 g of pyrogallol / benzaldehyde condensate with a coffee mill in the same manner as in Example of JP-A-11-217403, 100 mL of 0.1 N aqueous sodium hydroxide solution was obtained. Dissolved in. A sodium hydroxide aqueous solution of the pyrogallol / benzaldehyde condensate was spray-coated on the inner wall surface of the 3 L polymerization reactor and dried at 70 ° C. for 60 minutes. From the spray amount, the coating amount of pyrogallol / benzaldehyde condensate was 1 g / m ² . Next, the polymerization reactor was filled with 0.01 hydrochloric acid aqueous solution and treated at 50 ° C. for 20 minutes, and then the treated water was discharged.

Polymerization was carried out continuously for 5 batches by the suspension polymerization method of styrene shown below, but in the 6th batch, the amount of adhesion was so large that the polymerization could not be continued. Table 1 shows the effect of preventing polymerization adhesion after each batch.
Comparative Example 2
Example 1 was repeated except that 500 mL of acetone was used instead of 100 mL of the 0.1 N aqueous ammonia solution. A large amount of acetone vapor was generated during drying, which was dangerous. From the spray amount, the coating amount of pyrogallol / benzaldehyde condensate was 1 g / m ² .

  Although four continuous batch polymerizations were carried out by the suspension polymerization method of styrene shown below, the amount of adhesion was large in the fifth batch, and the polymerization could not be continued. The adhesion preventing effect after each batch at that time is shown in Table 1. Since it is difficult to dissolve in acetone with respect to 100 ml of ammonia water, it was diluted with 500 ml of a large amount of acetone, and unevenness, fish eyes and the like occurred during drying, and it was considered that the effect of preventing polymerization adhesion was weakened.

Comparative Example 3
After spray coating in Example 1, the same method operation was carried out except that the drying treatment was performed at 30 ° C. for 60 minutes under a nitrogen stream instead of drying at 70 ° C. for 60 minutes. The spray surface after the treatment was dry. When a small amount of water was sprayed, the coated surface peeled off.
Separately, after spray coating in Example 1, the polymerization reactor was used in the same manner except that it was dried at 70 ° C. for 60 minutes in a nitrogen stream at 60 ° C. for 60 minutes. The continuous polymerization of 4 batches was carried out by the suspension polymerization method of styrene shown in FIG. The adhesion preventing effect after each batch at that time is shown in Table 1. Since the volatilization of ammonia was insufficient, a sufficient adhesion preventing effect could not be obtained.

Test example: Suspension polymerization of styrene 1,000 g of distilled water, 4.0 g of calcium triphosphate, and dodecyl in an autoclave with a rotary stirrer having a capacity of 3 liters subjected to the treatment of Example 1 and Comparative Examples 1 to 3 above. Next, 0.03 g of sodium benzenesulfonate was charged, and then 3.6 g of benzoyl peroxide (25% wet product) and 0.9 g of butyl perbenzoate were dissolved in 900 g of styrene. Next, the autoclave is heated to a temperature of 90 ° C., and styrene is polymerized at the same temperature for 6 hours, and then the autoclave is heated to a temperature of 110 ° C. to completely react unpolymerized products. It was. Thereafter, the reaction system was cooled to a temperature of 30 ° C. to complete the polymerization.

The adhesion state of the inner wall surface of the polymerization vessel polymerized by each polymerization method was visually observed and judged according to the following criteria.
○: Adhesion adherence is not observed on the entire wall surface. Δ: Adhesion adherence is observed on a part of the wall surface. X: Adhesion adhesion is observed on the entire wall surface. In addition, after removing ammonia by drying, it can be seen that there is a continuous anti-adhesion effect of 10 batches or more. This is presumably because the polymerization adhesion inhibitor by heating was baked stably and uniformly after the ammonia and moisture were removed by evaporation. On the other hand, in the case of the treatment with the acidic compound aqueous solution, it seems that the neutralizing salt compound remained, so that the sustaining effect was reduced.

Claims (5)

  Before the vinyl monomer is polymerized in the reactor using water as a medium, the condensate of the phenolic compound and the aldehyde compound is applied to the inner wall of the polymerization reactor in the form of a volatile amine aqueous solution, and water and volatilization are performed by drying. Method for preventing adhesion of polymer to remove functional amine.   The condensate of a phenolic compound and an aldehyde compound is selected from at least one condensate of pyrogallol / benzaldehyde condensate, pyrogallol / formalin condensate, and pyrogallol / formalin / resorcinol condensate. Method for preventing adhesion of polymer.   Polymerization of a vinyl monomer using water as a medium is a polymerization method selected from suspension polymerization, microsuspension polymerization method, and emulsion polymerization. Prevention method.   After applying the condensate of phenolic compound and aldehyde compound to the inner wall of the polymerization reactor in the form of an aqueous volatile amine solution, water and volatile amines are removed by drying to prevent adhesion of the polymer, A method for producing a vinyl polymer, wherein a vinyl monomer is polymerized in a reactor as a medium.   A method for treating a vinyl monomer polymerization reactor in which a condensate of a phenolic compound and an aldehyde compound is applied to the inner wall surface of a polymerization reactor in the form of a volatile amine aqueous solution, and water and volatile amine are removed by drying.