JPH0247105A - Method for preventing polymer scale adhesion - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for preventing the adhesion of polymer scale, particularly in the polymerization of monomers having ethylenic double bonds. The present invention relates to a method that can effectively prevent adhesion.

[Conventional technology]

BACKGROUND ART In a method of producing a polymer by polymerizing monomers in a polymerization vessel, there is a known problem that the polymer adheres as scale to the inner wall surface of the polymerization vessel. When polymer scale adheres to the inner wall surface of a polymerization vessel, a great deal of effort and time is required to remove the polymer scale. Furthermore, there are disadvantages such as a decrease in the yield of the polymer, a decrease in the cooling capacity of the polymerization vessel, and a deterioration in the quality of the product polymer due to the adhering polymer scale peeling off and contaminating the product.

Conventionally, as a method for preventing polymer scale from adhering to the inner wall surface of a polymerization vessel, for example, a method of applying polar compounds, dyes, pigments, etc. to the inner wall surface (Japanese Patent Publication Nos. 45-30343 and 45-30835) has been used. , a method of applying an aromatic amine compound (Japanese Unexamined Patent Publication No. 51-50887), a method of applying a reaction product of a phenol compound and an aromatic aldehyde (Japanese Unexamined Patent Publication No. 55-54317), etc. are known.

These methods are effective in preventing the adhesion of polymer scale in the polymerization of vinyl halide monomers such as vinyl chloride, or monomer mixtures mainly composed of vinyl chloride and containing small amounts of monomers that can be copolymerized with these monomers. It is.

[Problem to be solved by the invention] However, when the monomer subjected to polymerization is a monomer having other ethylenic double bonds such as styrene, α-methyluntyrene, acrylic ester, acrylonitrile, etc. Because these monomers have a significantly high solubility in the coating film formed by the above-mentioned anti-adhesion method, part or all of the coating film is dissolved and lost, resulting in polymer scale formation. It is not possible to effectively prevent the adhesion of the polymer to the inner wall surface of the polymerization vessel.

Therefore, an object of the present invention is to provide a method that can effectively prevent the deposition of polymer scale in the polymerization of not only halogenated vinyl monomers but also monomers having a wide range of ethylenic double bonds. It's about doing.

[Means to solve the problem]

The present invention solves the above problems and provides a method for preventing the adhesion of polymer scale during the polymerization of a monomer having an ethylenic double bond in a polymerization vessel, the method comprising: A method for preventing the adhesion of polymer scale in which the polymerization is performed after previously treating other parts with which the monomer comes into contact with a treatment liquid containing at least one selected from a titanium compound, a zinc compound, a nickel compound, and an aluminum compound. It provides:

Examples of the titanium compound used in the present invention include titanium oxides, halides, inorganic acid salts, organic acid salts, oxyacids, salts thereof, and other compounds containing titanium. Specifically, for example, titanium oxides such as titanium oxide (■) TiO□; titanium chloride (IV) TiCj24,
Halides such as titanium chloride (I[I) TiCffiz, titanium potassium fluoride TiKJ, titanium (IV) iodide TiI4; titanium salts of inorganic acids such as titanium sulfate Tt (504) z; titanate H4Ti0a, metatitanate H2TiOz Oxygen acids of titanium such as sodium titanate Na4TiO4, sodium metatitanate Na2Ti0
3. Ammonium pentafluorotitanate(III) (
NH4) z(TiFs], hexafluorotitanium (I
Ammonium I[)ate (NH4)3 (TiFb), Ammonium hexafluorotitanate(IV)ate (NH4)
! Various titanates such as (TiFa); acetylacetonatotitanium (II) oxide TiO (CHsCOCHCOC
H+)z, 2TiO(CaO
2) z, titanium tetraisopropoxide Ti (OCR
(CH3)! ) Examples include organic titanium compounds such as a. Among these titanium compounds, preferred are, for example, titanium sulfate Ti (SO4) z,
Examples include titanate H, TiO, and metatitanate H2TiOi.

Examples of the zinc compound include zinc oxides, halides, inorganic acid salts, hydroxides, organic acid salts, and other zinc-containing compounds. Specifically, for example, oxides such as zinc oxide ZnO; sulfides such as zinc sulfide ZnS; zinc bromide ZnB
rt, zinc halides such as zinc chloride ZnC1z, zinc iodide Zn12; zinc sulfate ZnSO4, zinc nitrate Z
n(Noff)z1 Inorganic acid salts of zinc such as zinc phosphate Zn (POa)z, zinc carbonate ZnC0, etc.; zinc hydroxide Zn
Zinc hydroxide such as (OH) z; Zinc acetate Zn (C
H3CO2)2, Zinc benzoate (C6H5COO
)z, zinc lactate Zn (C:+HsOs)z, zinc phenolsulfonate Zn (C,04(011)SO:l
) z, zinc salicylate ZnCCb■4 (OH)
COO) z, Zinc stearate (CiaH3sO
z)z, Zinc dibenzyldithiocarbamate Zn (
(Ci, HsCHz) zNCSS ) 2, Zinc dibutyldithiocarbamate Zn ((CaHq) 2
NCSS) z, zinc diethyldithiocarbamate Z
Organic acid salts of zinc such as n((CzHs) zNCSS ) z; acetylacetonatozinc (U ) Zn (C1
Examples include organic zinc compounds such as hCOCIICOCH:+)z. Among these zinc compounds, preferred examples include zinc sulfate Zn5On, zinc nitrate Zn(No:+)z, and zinc carbonate ZnCO3.

Examples of the nickel compound include nickel oxides, halides, inorganic acid salts, organic acid salts, and other nickel-containing compounds. Specifically, for example, nickel oxide (
Nickel oxides such as lNiO1 nickel (III oxide) NizOs; nickel (II) bromide N1Brz
, nickel(II) chloride NiCj! Nickel halides such as □; Nickel sulfate (II) NiSO4, Nickel nitrate (Il, ) N1 (No3) z, Nickel sulfate (II) ammonium (NH4) zNi (SOa)
2. Nickel carbonate (If) NiC01・2Ni(O
H) Nickel z-sulfamate (It) Ni (
Inorganic acid salts of nickel such as NHzSO+) z; Nickel acetate (U)
II) N1(HCOO)z, nickel lactate (I[
) Ni (organic acid salts of nickel such as CI (3cH (OR) Coo: l z; acetylacetonatonickel (I[
) N1(C8:+C0CHCOCH3)2 and other organic nickel compounds.

Among these nickel compounds, preferable ones include, for example, nickel sulfate (n) NiSO4, nickel nitrate (If) N1 (NO+) z, nickel (II) sulfate ammonium (NH4) zNi (SO4
) z is mentioned.

Examples of aluminum compounds include aluminum oxide,
Examples include halides, inorganic acid salts, hydroxides, organic acid salts, and other aluminum-containing compounds. in particular,
For example, oxides of aluminum such as aluminum oxide 81203; aluminum bromide A II! Br, , ,
Aluminum halides such as aluminum chloride AfCfi; aluminum sulfate Al□(SO4)3, aluminum nitrate Al(N(h)3, aluminum phosphate AffiPO, aluminum silicate An□03)
3SiOz, aluminum ammonium sulfate A j!
NH4(SO4)z, potassium aluminum sulfate A2K(SOn)z, sodium aluminum sulfate A
Inorganic salts of aluminum such as 2Na (SO4) 2; aluminum hydroxide All! (OHh, aluminum hydroxide such as aluminum metahydroxide AfO(OH); sodium aluminate Na CAN (OH)4),
Metal salts of aluminate such as barium aluminate Ba (Al1 (OH)s ); aluminum acetate A j! (
CH3COO) x , aluminum laurate A l
Organic acid salts of aluminum such as (CH3(CHI)1OCOO)3; acetylacetonadoaluminum80 (CH3COCHCOCH3):1, aluminum isopropoxide compounds, and the like. Among these aluminum compounds, preferable ones include, for example, aluminum nitrate A l (NOz) 3 , aluminum ammonium sulfate A I NH4 (SO4) and aluminum hydroxide Al (OH) 3 .

In the method of the present invention, one type of the above titanium compound, zinc compound, nickel compound, and aluminum compound may be used alone or in combination of two or more types.

In the method of the present invention, in order to prevent the polymer from adhering to the inner wall surface of the polymerization vessel, at least one compound selected from the titanium compound, zinc compound, nickel compound, and aluminum compound (hereinafter referred to as "metal The inner wall surface of the polymerization vessel and other parts that come into contact with the monomer during polymerization are treated with a treatment solution containing the compound (referred to as "compound"). In this treatment, a treatment liquid is prepared by dissolving or dispersing one or more of the above compounds in an appropriate solvent, and this treatment liquid is applied to the inner wall surface of the polymerization vessel and other areas that the monomers come into contact with during polymerization. This can be carried out, for example, by contacting with a stirring shaft, stirring blade, or the like. This treatment is preferably carried out at temperatures above 40°C, particularly preferably between 65 and 95°C.
The heating is carried out continuously for preferably 10 minutes or more, more preferably 30 minutes or more while heating at °C. The treatment liquid after this treatment may be discharged from the polymerization vessel.

The method of heating the treatment liquid while it is in contact with the inner wall surface of the polymerization vessel, for example, involves filling the polymerization vessel with the treatment liquid,
Examples include a method of heating the treatment liquid, and a method of heating the jacket of the polymerization vessel while spraying the treatment liquid onto the inner wall of the polymerization vessel to form a wet wall using a shower or the like. If the temperature of the heat treatment is too low or the time is too short, the amount of polymer attached will increase.

The concentration of the metal compound in the treatment liquid is usually preferably 0.1 to 5% by weight, more preferably 0.3 to 3% by weight, particularly preferably 0.5 to 1% by weight. If the concentration of the compound is too low, it will be difficult to sufficiently prevent the polymer from adhering to the inner wall surface of the polymerization vessel, and if the concentration is too high, it may adversely affect the quality of the product polymer.

The solvent for dissolving or dispersing the metal compound is water and an organic solvent miscible with water, such as alcoholic solvents such as methanol, ethanol, and n-propyl alcohol; and esters such as methyl formate, ethyl formate, and methyl acetate. Solvents include ketone solvents such as acetone and methyl ethyl ketone, and these may be used alone or as a mixed solvent of two or more.

As a result of this treatment, coloring or changes in the surface gloss of the inner wall surface of the polymerization vessel and other parts that come into contact with monomers during polymerization can be seen, so that a film or adsorption film of the metal compound is formed by this treatment. It is thought that

After treating the inner wall surface of the polymerization vessel and other parts that come into contact with monomers during polymerization with a treatment solution containing the metal compound and washing with water as described above, the polymerization vessel is treated with an ethylenic polymer in accordance with a conventional method. A monomer having a bond, a polymerization initiator, other necessary polymerization media such as water, and additives such as a monomer dispersion aid may be charged and polymerized.

Monomers having an ethylenic double bond to which the method of the present invention is applied include, for example, vinyl halides such as vinyl chloride, vinyl esters such as vinyl acetate and vinyl propionate, acrylic acid, methacrylic acid, and the like. esters or salts of maleic acid or fumaric acid and their esters or anhydrides, diene monomers such as butadiene, chloroprene, and isoprene, as well as styrene, α-methylstyrene, acrylic esters, acrylonitrile, vinylidene halides, and vinyl ethers. Examples include.

The method of the present invention is effective regardless of the material of the inner wall of the polymerization vessel, such as stainless steel, lined glass, etc.

Further, the method of polymerization to which the method of the present invention is applied is not particularly limited, and any polymerization method such as suspension polymerization, emulsion polymerization, solution polymerization, and bulk polymerization is effective.

Therefore, any commonly used additives added to the polymerization system can be used without any restrictions. That is,
For example, suspending agents such as partially saponified polyvinyl alcohol, methyl cellulose, polyacrylate, solid dispersants such as calcium phosphate and hydroxyapatite, anionic emulsifiers such as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium dioctyl sulfosuccinate, and sorbitan. Nonionic emulsifiers such as monolaurate and polyoxyethylene alkyl ether, fillers such as calcium carbonate and titanium oxide, stabilizers such as tribasic lead sulfate, calcium stearate, dibutyltin dilaurate, and dioctyltin mercaptide, rice wax, and stearin. Lubricant such as acid, DOP, DBP
chain transfer agents such as trichlorethylene and mercaptans, pHfiJl adjusters, diisopropyl peroxydicarbonate, α,α'-azobis-2゜4
-dimethylvaleronitrile, lauroyl peroxide, potassium persulfate, cumene hydroperoxide, P
- Even in a polymerization system in which a polymerization catalyst such as menthane hydroperoxide is present, the method of the present invention can effectively prevent the deposition of polymer scale.

Polymerization in which the method of the present invention is particularly suitably carried out is, for example, suspension polymerization or emulsion polymerization of vinyl halides such as vinyl chloride, vinylidene halides, or monomer mixtures mainly containing these. In addition, stainless steel polymerization vessels are mainly used for polymer beads such as polystyrene, polymethyl methacrylate, and polyacrylonitrile.
Latex manufacturing, SBR, NBR, CR, IR, I
It is also suitable for the production of synthetic rubbers such as IR (these synthetic rubbers are usually produced by emulsion polymerization) and polymerization for producing ABS resins.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

Brevo 1mer. S1 The prepolymers used in each side below were prepared in the following manner.

In a polymerization vessel, 6000 g of styrene, 720 g of polybutadiene rubber, mineral oil (CP-50 manufactured by Idemitsu Kosan)
480 g and n-dodecyl mercaptan 6000 g
was charged and reacted at 115°C for 5 hours to prepare a prepolymer.

1 to 20 6 1 On each side, first, water 11 is charged in a stainless steel polymerization vessel with an internal volume of 20 f and equipped with a stirrer, the metal compounds shown in Table 1 are added to prepare a treatment liquid, and the inside of the polymerization vessel is heated. After that, the treated liquid was discharged from the polymerization vessel, and the inside of the polymerization vessel was washed with water.

However, in Comparative Example 1, no treatment with a metal compound was performed. For each side, the metal compound used, the concentration of the metal compound in the treatment solution, and the temperature and time of the heat treatment are as shown in Table 1.

Next, 7,000 ml of water was added to the polymerization vessel treated in this way.
g, 7000 g of prepolymer obtained in the above preparation example
Hydroxyapatite 70g 1 Sodium dodecylbenzenesulfonate 0.14g, Benzoyl peroxide 17
．． 5 g and 10.5 g of t-butyl perbenzoate were reacted at 92°C for 3.5 hours, and then heated to 135°C.
The reaction was carried out for 1 hour to produce a polymer.

After the polymerization was completed, the amount of polymer scale attached to the inner wall surface of the polymerization vessel was measured. The results are shown in Table 1.

21 to 35, ... 12 On each side, a stainless steel polymerization vessel with an internal volume of 1000 N and a stirrer was coated with a treatment solution containing the metal compounds shown in Table 2 in the same manner as in Example 1. The parts that come into contact with the monomer during polymerization were treated. however,
In Comparative Example 2, treatment with a treatment liquid containing a metal compound was not performed. Note that for each side, the type of metal compound used, the concentration of the metal compound in the treatment liquid, and the temperature and time of the heat treatment are as shown in Table 2.

Next, in the polymerization vessel treated in this way, 400 kg of water,
Styrene 260 kg, acrylonitrile 140 kg
, 400 g of partially saponified polyacrylamide and α.

1.2 kg of α'-azobisisobutyronitrile was charged and reacted at 90°C for 5 hours to produce a polymer.

After the polymerization was completed, the amount of polymer scale attached to the inner wall surface of the polymerization vessel was measured. The results are shown in Table 2.

36-50 3 On each side, in a stainless steel polymerization vessel with an internal volume of 1000 ffi and a stirrer, the inner wall surface of the polymerization vessel and other areas were treated with a treatment solution containing the metal compounds shown in Table 3 in the same manner as in Example 1. The parts that come in contact with the monomers were treated. However, in Comparative Example 3, treatment with a treatment liquid containing a metal compound was not performed. Note that on each side, the type of metal compound used, the concentration of the metal compound in the treatment liquid, and the temperature and time of the heat treatment are as shown in Table 3.

Next, in the polymerization vessel treated in this way, 400 kg of water,
Polybutadiene latex (solid content = 50% by weight)
270 kg, styrene 70 kg, acrylonitrile 30
625 g of 5 L-dodecyl mercaptan and 700 g of potassium persulfate were charged and reacted at 50°C for 10 hours to produce a polymer.

After the polymerization was completed, the amount of polymer attached as scale to the inner wall of the polymerization vessel was measured. The results are shown in Table 3.

〔Effect of the invention〕

According to the method of the present invention, it is possible to effectively prevent polymer scale from adhering to the inner wall surface of a polymerization vessel during the polymerization of a monomer having an ethylenic double bond, which has been difficult in the past. In particular, monomers with high solubility, such as styrene,
Adhesion of polymer scale can be prevented even in the case of polymerization of a polymerization system containing α-methylstyrene, acrylic acid ester, and acrylonitrile. By treating the inner walls of the polymerization vessel with a treatment liquid containing at least one selected from titanium compounds, zinc compounds, nickel compounds, and aluminum compounds in every batch or once every few batches, the inner walls of the polymerization vessel, etc. The polymerization vessel can be used repeatedly without polymer scale adhering to the surface. Furthermore, since there is no need to add anything to the polymerization system during polymerization to prevent polymer scale, the quality of the resulting polymer is not affected.

Agent Patent Attorney Comrade Iwamiya

Claims (1)

[Claims] A method for preventing the adhesion of polymer scale during the polymerization of a monomer having an ethylenic double bond in a polymerization vessel, the method comprising the steps of: A method for preventing adhesion of polymer scale, wherein the polymerization is performed after previously treating other parts of the body with a treatment liquid containing at least one selected from a titanium compound, a zinc compound, a nickel compound, and an aluminum compound.