JPH06328049A - Removal of attaching polymer from surface of manufacturing equipment - Google Patents

Abstract

PURPOSE:To remove a polymer attaching to a manufacturing equipment after the polymerization of a water-soluble unsaturated ethylenic monomer in a short time and at high removal efficiency. CONSTITUTION:This method for removing an attaching polymer from the surface of manufacturing equipment is to remove a polymer attaching to the surface of manufacturing equipment, which is produced by polymerization of a water-soluble unsaturated ethylenic monomer, by treating the attaching polymer using a radical initiator and/or a reducing agent.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for removing polymer adhering to the surface of manufacturing equipment after polymerization of a water-soluble ethylenically unsaturated monomer.

[0002]

BACKGROUND OF THE INVENTION Water-soluble or water-swellable polymers obtained by polymerizing water-soluble ethylenically unsaturated monomers are
It is a useful polymer that has been used in a wider range of applications than before. In particular, water-swellable polymers have been recently used as sanitary products, sanitary products, disposable diapers, disposable rags, water retention agents,
In addition to agricultural and horticultural products such as soil conditioners, it is used in various applications such as sludge coagulants, anti-condensation agents and oil dehydrators.

The above polymers are generally reverse phase suspension polymerizations,
The polymer is synthesized by a method such as reverse phase emulsion polymerization, aqueous solution polymerization, polymerization in an organic solvent, and then various processes such as dehydration, surface modification, pulverization and granulation are carried out. In addition, a part of the produced polymer adheres to the production equipment, which adversely affects the production of the polymer. The problem of the adhesion of this polymer to the production equipment is described in JP-A-62-172006, JP-A-61-231004, and JP-A-57-74309.
And Japanese Patent Application Laid-Open No. 61-36763. To cope with this problem, various countermeasures have been studied so far, for example, the addition of a surfactant can suppress the adhesion of the polymer (Japanese Patent Laid-Open No. 61-36663), or the polymer on the wall of the polymerization tank. Fluorine-based resin coating is applied to prevent adhesion (JP-A-60-55002).
JP-A-56-3254, etc.), methods for improving the smoothness of the wall surface of the polymerization tank have been reported for the purpose of suppressing polymer adhesion. Although these methods are effective in suppressing the adhesion of the polymer to the manufacturing equipment, they are not techniques for removing the adhered polymer. As a method for removing the polymer adhering to the manufacturing equipment, Japanese Patent Laid-Open No. 01-
Japanese Patent No. 242602 describes a method of treating a deposited polymer with caustic soda or potassium hydroxide. However, this method has a problem in that it takes a long time to remove the polymer, and since strong alkaline water is used for the treatment, it is difficult to handle the liquid before and after washing.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned state of the art, the present invention removes a polymer adhering to a manufacturing equipment after polymerization of a water-soluble ethylenically unsaturated monomer in a short time and with extremely high removal efficiency. The purpose is to provide a method of obtaining.

[0005]

[Means for Solving the Problems]

[Summary of the Invention] The present inventors have found that when the following specific chemicals are used as a treatment agent, the removal of the adhered polymer can be performed in a very short time with high efficiency, and the present invention is completed. I arrived. That is, the method of the present invention is a method of removing a polymer produced by polymerization of a water-soluble ethylenically unsaturated monomer and adhering to the surface of manufacturing equipment, wherein the attached polymer is used as a radical generator and / or a reducing agent. It is characterized by processing by.

[Detailed Description of the Invention] <Target Polymer> The polymer to which the method of the present invention is applied is a water-soluble or water-swellable polymer produced by polymerization of a water-soluble ethylenically unsaturated monomer. Here, the water-soluble ethylenically unsaturated monomer is a water-soluble group having a functional group derived from a carboxylic acid or (and) salt thereof, phosphoric acid or (and) salt thereof, sulfonic acid or (and) salt thereof. And ethylenically unsaturated monomers. Specifically, (meth) acrylic acid or a salt thereof, maleic acid or a salt thereof, itaconic acid or a salt thereof, vinylsulfonic acid or a salt thereof, 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof, 2-acryloyl. Examples thereof include ethanesulfonic acid or a salt thereof, 2-acryloylpropanesulfonic acid or a salt thereof, 2-methacryloylethanesulfonic acid or a salt thereof, vinylphosphonic acid or a salt thereof.

Monomers copolymerizable with the above-mentioned monomers, such as (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, (poly) ethylene glycol mono (meth) acrylate, 2-hydroxyethyl ( A polymer obtained by copolymerizing (meth) acrylate or the like is also an object to which the method of the present invention is applied.

Further, the polymer to which the present invention is applied may contain an inert inorganic powder such as fine particle silica, titanium dioxide powder, and alumina powder as an additive. The method for producing the target polymer of the present invention is not particularly limited, and the method of the present invention can be effectively applied to a polymer produced by any conventionally known polymerization method.

<Treatment of Removal of Adhering Polymer> According to the method of the present invention, the polymer produced by the polymerization of the water-soluble ethylenically unsaturated monomer and adhered to the surface of the production equipment is treated with the following radical generator and / or It is removed by treating with a reducing agent. Here, the “production equipment surface” refers to a portion of the production equipment, such as the inner wall surface of the polymerization reactor, the agitator surface, the inner wall surface of the polymer transfer line, which the polymer comes into contact with during the production of the polymer.

Examples of the radical generator used in the present invention include the following. (A) Inorganic peroxides Inorganic peroxides such as hydrogen peroxide, potassium persulfate, sodium persulfate, ammonium persulfate and other persulfates, etc. (b) Organic peroxides t-butyl hydroperoxide, cumene hydroper Hydroperoxides such as oxides and dicumyl peroxide, di-t-butyl peroxide, dialkyl peroxides such as bistriphenylethyl peroxide, percarboxylic acids such as perlauric acid and perbenzoic acid, and peroxalic acid dit. -Peroxides such as butyl and t-butyl perbenzoate, and organic peroxides such as diacyl peroxides such as benzoyl peroxide and lauroyl peroxide (C) Azo compounds azoisobutyronitrile, 2,2 ′ -Azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis (N,
N'-dimethyleneisobutylamidine) dihydrochloride, 4,
Azo compounds such as 4'-azobis (4-cyanovaleric acid), etc. Among these, radical generators exhibiting oxidizing properties such as inorganic peroxides and organic peroxides are, for example, reducing substances described below, so-called reducing agents. It can also be used in combination with.
Such a combination is preferable since a high polymer removing effect can be obtained even at a low processing temperature.

Examples of the reducing agent used in the present invention include acidic sulfites such as sodium sulfite and sodium hydrogen sulfite; tertiary amines such as dimethylaniline and dimethyltoluidine; divalent iron compounds such as ferrous chloride; nitrate,
L-ascorbic acid (salt), etc. can be mentioned.
The above radical generator and / or reducing agent are preferably used in the form of an aqueous solution dissolved in water or a liquid dispersed in water, and the concentration thereof is 0.001 wt% from the viewpoint of the polymer removing effect and economical viewpoint. % Or more, particularly 0.01 to
It is preferably 3.0% by weight.

The removal treatment of the adhering polymer is carried out by bringing the treating agent (aqueous solution or water dispersion) into contact with the adhering polymer on the surface of the manufacturing equipment. For example, fill the inside of the device where the polymer is attached with a radical generator aqueous solution,
In order to improve the removal effect, the removal treatment is carried out under heating and / or stirring as necessary. When the amount of attached polymer is small, for example, a sufficient effect can be obtained even if the equipment part to which the polymer is attached is spray-washed with a radical generator aqueous solution at a temperature as necessary. In some cases, it is possible to employ a method in which the above treatment agent is brought into contact with the adhering polymer as a powder or a 100% solution as it is, and then contacted with water or removed by an air stream.

[0013]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited thereto. Production Example 1 150 kg of cyclohexane was charged into a 300 liter jacketed SUS316 stirred tank, 1.0 kg of sorbitan monostearate of HLB3 was added and dissolved, and then nitrogen gas was blown thereinto to expel dissolved oxygen (solution A ). Into another 300 liter jacketed stirring tank, 74.7 kg of a 37.6% by weight acrylic acid aqueous solution,
While cooling from the outside, 46.7 kg of a 25 wt% sodium hydroxide aqueous solution was gradually added to neutralize 70 mol%. Furthermore, N, N-methylenebisacrylamide 0.0
After 42 kg and 0.104 kg of potassium persulfate were added and dissolved, nitrogen gas was blown thereinto to expel dissolved oxygen (solution B). A 500-liter polymerization reactor made of SUS316 equipped with a stirrer, a jacket, a reflux condenser, and a nitrogen gas inlet pipe was equipped with three pitched paddle blades with anchor blades (blade diameter / tank diameter = 0.7) as stirring blades. Then, the above liquids (a) and (b) were added, and the mixture was stirred and dispersed, and then heated to maintain the jacket at 55 to 65 ° C. for 1 hour to carry out a polymerization reaction. Got Polymerization liquid (solution C)
Was extracted, and the above polymerization operation was repeated 15 times. The amount of attached polymer on the inner wall surface of the polymerization reactor after the final polymerization operation was 30 to 35 kg.

Production Example 2 The (c) liquid of Production Example 1 was transferred to a 500 liter stirring tank made of SUS316 equipped with a stirrer, a jacket, a reflux condenser, and a reflux receiving tank (decanter type), and then heated. The jacket was kept at 110 to 120 ° C. to dehydrate the water contained in the polymer. During the dehydration, water evaporated by heating and cyclohexane were cooled by a reflux condenser and led to a reflux receiving tank, and then water was taken out of the system, and cyclohexane was completely returned to the stirring tank. When the water content of the polymer reached 20% by weight, the heating was stopped and the obtained dehydrated polymer and cyclohexane slurry liquid was extracted. The above dehydration operation was repeated 15 times. The amount of attached polymer on the inner wall surface of the stirring tank after the final dehydration operation is 35 to 4
It was 0 kg.

Production Example 3 414 parts by weight of acrylic acid, 4380 parts by weight of a 37% by weight aqueous solution of sodium acrylate, 54.97 parts by weight of polyethylene glycol diacrylate (n = 8) as a crosslinking agent, sodium hypophosphite monohydrate After using 9.76 parts by weight and 670 parts by weight of ion-exchanged water to obtain a monomer aqueous solution (solution E) having a concentration of 37% and a degree of neutralization of 75%, nitrogen gas was blown in to expel dissolved oxygen. Attach a lid to a jacketed stainless steel double-armed beading machine (kneader) having a sigma-type blade with an internal capacity of 500 liters, and feed 200 kg of the above solution (d) into this reactor, and inject nitrogen gas to carry out the reaction. The system was replaced with nitrogen. Then, two sigma type blades were rotated, and while heating the jacket with warm water at 35 ° C., 0.095 kg of ammonium persulfate and 0.0044 kg of sodium hydrogen sulfite were added to initiate polymerization. The gel body of the water-swellable polymer obtained 60 minutes after the initiation of the polymerization was extracted. The above polymerization operation was repeated 5 times. The amount of attached polymer on the inner wall surface of the polymerization reactor (kneader) after the final polymerization operation was 40 to 45 kg.

Examples 1 to 6 and Comparative Examples 1 to 6 The polymerization reactor to which the polymer was attached in Production Example 1 was filled with an aqueous solution of a treating agent of the type shown in Table 1 and attached under the conditions shown in the same table. Polymer removal treatment was performed. The results obtained are shown in Table 1.

Examples 7 to 12 The stirring tank to which the polymer was adhered in Production Example 2 was filled with an aqueous solution of a treating agent of the type shown in Table 2, and the adhering polymer was removed under the conditions shown in the same table. . Second result obtained
Shown in the table.

Examples 13 to 18 The polymerization reactor to which the polymer was attached in Production Example 3 was filled with an aqueous solution of a treating agent of the type shown in Table 3, and the attached polymer was removed under the conditions shown in the same table. It was The results obtained are shown in Table 3.

[Table 1]

[Table 2]

[Table 3]

[0019]

EFFECTS OF THE INVENTION According to the method of the present invention, a polymer produced by polymerization of a water-soluble ethylenically unsaturated monomer and adhering to the surface of manufacturing equipment can be removed in an extremely short time and at a high removal rate. it can. In addition, since the time required for removing the adhered polymer is shortened by the method of the present invention, the polymer production apparatus can be operated continuously for a long period of time, and therefore the polymer product quality can be further stabilized.

Front page continuation (72) Inventor Osamu Nakajima 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Petrochemical Co., Ltd. Yokkaichi Research Institute Chemicals Research Laboratory (72) Inventor, Katsuhiko Itakura 1 Toho-cho, Yokkaichi-shi, Mie Address Mitsubishi Petrochemical Co., Ltd. Inside the Yokkaichi Research Institute Chemicals Research Laboratory (72) Inventor Masayuki Yamashita No. 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Petrochemical Co., Ltd. Within Yokkaichi Research Institute Chemicals Research Center (72) Invention Person Hino Mori Shunichi 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Petrochemical Co., Ltd. Yokkaichi Research Institute Chemicals Research Center

Claims (1)

[Claims] 1. A method for removing a polymer produced by polymerization of a water-soluble ethylenically unsaturated monomer and adhering to the surface of manufacturing equipment, wherein the adhering polymer is treated with a radical generator and / or a reducing agent. A method characterized by the following.