JP3325621B2 - Method for producing water-in-oil cationic polymer emulsion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel process for producing a water-in-oil cationic polymer emulsion, and more particularly, to a water-soluble and storage-stable good retention agent for papermaking. And drainage improver,
The present invention relates to a method for producing a water-in-oil cationic polymer emulsion exhibiting high performance for uses such as a flocculant and a dehydrating agent for industrial wastewater and sewage and human waste treatment.

[0002]

2. Description of the Related Art Conventionally, cationic polymer flocculants have been widely used for applications such as retention and drainage improvers for papermaking, flocculants and dehydrating agents for industrial wastewater and sewage and human waste treatment. . These cationic polymer flocculants are generally a homopolymer of a cationic vinyl monomer or a copolymer thereof with another water-soluble vinyl monomer,
The predominant product form was a powdered polymer. on the other hand,
In recent years, due to its good handleability, a number of water-in-oil polymer emulsion-type polymer flocculants have been proposed as product forms. For example, Japanese Patent Publication No. 54-37986 discloses a monomer aqueous solution of 30 to 70% by weight and a hydrophobic liquid 70%.
A method of obtaining a water-in-oil polymer emulsion by emulsifying and dispersing about 30% by weight of a surfactant using a surfactant has been proposed. JP-A-63-90510 discloses a method containing a water-soluble vinyl monomer and a crosslinking agent. After mixing an aqueous solution and an organic dispersion medium containing a hydrophobic surfactant having an HLB value of 3 to 6, the mixture is polymerized at a temperature of 30 to 80 ° C. in the presence of a radical polymerization catalyst to produce a water-in-oil emulsion polymer. In addition, Japanese Patent Publication No. 47156/1976 discloses a water-soluble and ethylenically unsaturated monomer aqueous solution.
A water-in-oil emulsion composed of 0-70% by weight, a hydrophobic liquid, a concentration of 0.1-10% by weight of a water-in-oil emulsifier and a free radical initiator is prepared, and heated to generate free radicals. A method has been proposed in which the monomer is produced and the monomer is polymerized to form a polymer latex, which is used for concentrating and dehydrating solids from sewage and industrial waste liquid.

In these conventional methods for producing water-in-oil polymer emulsions, peroxides are used as polymerization initiators.
Radical polymerization initiators such as persulfates and azo compounds have been used alone, or redox-based polymerization initiators obtained by combining peroxides and persulfates with reducing agents have been used. Furthermore, the basic performance requirement for these polymer emulsions is to aggregate target suspended particles in the papermaking process, wastewater treatment process, etc.However, in order to meet this requirement, how to increase the molecular weight of the polymer is a major issue. It is. However, in the water-in-oil type polymer emulsion produced by the conventional production method, if the polymerization conditions for increasing the molecular weight are selected, storage stability deteriorates, and during storage, sedimentation, reagglomeration, thickening, etc. of the polymer particles occur. However, there is a large problem in that the performance and the water solubility decrease with time, and it has been difficult to sufficiently satisfy both the performance and the storage stability.

[0004]

In the above-mentioned conventional water-in-oil polymer emulsion, various improvements have been made in the monomer composition, the surfactant composition, and the like, but the above-mentioned problems have not been solved, and the performance and storage stability have not been solved. There is a strong need to develop a method for producing a water-in-oil polymer emulsion having a good balance of properties and the like. The present invention is a water-in-oil cationic polymer emulsion having good water solubility, dispersion stability, storage stability, and low viscosities,
Provided is a method for producing a water-in-oil cationic polymer emulsion exhibiting high performance for applications such as retention and drainage improvers for papermaking, flocculants and dehydrating agents for industrial wastewater and sewage treatment. The purpose is to:

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the conventional problems, and as a result, the polymerization conditions using a special polymerization initiator system, which has not been used at all, have been investigated. ) By polymerization, a polymer emulsion containing a high-molecular-weight emulsion polymer and having good storage stability can be produced, and it has been found that the above problems can be solved. Thus, the present invention has been completed.

According to the present invention, a cationic vinyl monomer represented by the following general formula (Chemical Formula 2) is homopolymerized in the presence of water, a hydrophobic organic liquid, a nonionic surfactant, When a water-in-oil polymer emulsion is produced by copolymerization with a hydrophilic vinyl monomer, a peroxide is not used as a polymerization initiator, and a reducing agent is used alone, or an azobis-based polymerization initiator and / or metal This is a method for producing a water-in-oil cationic polymer emulsion, which is used in combination with a salt and initiates polymerization by adding 5 to 300 ppm per monomer.

[0007]

Embedded image

[0008] (In the formulas, A represents an oxygen atom or NH; Z is a hydroxy alkylene group having 2 to 4 carbon alkylene group or a C 1 to 4 carbon atoms; R ₁ is hydrogen or a methyl group; R ₂ is 1 to the number of carbon atoms R ₃ and R ₄ are each independently an alkyl group having 1 to 4 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms; X ⁻ is a salt Represents an anion that forms

The cationic vinyl monomer represented by the general formula (1) used in the present invention includes dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminohydroxypropyl (meth) acrylate and the like. Dialkylamino such as neutralized salt or quaternized dialkylamino (hydroxy) alkyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminohydroxypropyl (meth) acrylamide, etc. Neutralized salts or quaternized (hydroxy) alkyl (meth) acrylamides are exemplified.

Other water-soluble vinyl monomers used in the present invention include nonionic vinyl monomers such as (meth) acrylamide, N, N'-dimethyl (meth) acrylamide, acrylonitrile, methyl methacrylate, and hydroxypropyl (meth) acrylate. Monomer, vinyl pyridine,
Examples include cationic vinyl monomers such as vinylimidazoline and the like, and anionic vinyl monomers such as acrylic acid, methacrylic acid, sodium acrylate and acrylamidopropanesulfonic acid.

The hydrophobic organic liquid used in the present invention includes:
Examples thereof include kerosene, light oil, hexane, isoparaffin, benzene, toluene, xylene, and other aliphatic hydrocarbons or aromatic hydrocarbons.

The nonionic surfactant used in the present invention includes polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan tristearate, polyoxyethylene lauryl ether, polyethylene glycol monooleate, sorbitan monolaurate and the like. Can be

In the present invention, peroxides such as hydrogen peroxide, benzoyl peroxide, lauroyl peroxide, tert-butyl hydroperoxide, ammonium persulfate and potassium persulfate are not used as the polymerization initiator. In the present invention, as a polymerization initiator, a reducing agent alone,
Alternatively, it is important to use it in combination with an azobis-based polymerization initiator or in combination with a trace amount of metal ion.

The reducing agent used in the present invention is not particularly limited, but ferrous chloride, ferrous sulfate, cuprous chloride, cuprous sulfate, sodium sulfite, sodium hydrogen sulfite, sodium thiosulfate, L -Ascorbic acid, alkanolamines, sodium formaldehyde sulfoxylate, hydrazine and the like can be used. Further, the addition amount of these reducing agents is preferably 10 to 200 ppm. If it is 5 ppm or less, it is very difficult to initiate a polymerization reaction, and if it is 300 ppm or more, it becomes difficult to sufficiently increase the molecular weight of the polymer. In the present invention, two or more of these reducing agents can be used in combination.

In the present invention, a reducing agent as a polymerization initiator can be used in combination with an azobis-based polymerization initiator. The azobis-based polymerization initiator is not particularly limited, but includes 2,2′-azobisisobutyronitrile,
2'-azobis (4-methoxy-2,4-dimethylvaleronitrile, 2,2'-azobis (2-aminodipropane) dihydrochloride, etc. Depending on the polymerization conditions, an azobis-based polymerization initiator may be used. When the reducing agent is allowed to act in combination with the above, the unreacted monomer in the polymer may be reduced in some cases.

Further, in the present invention, a reducing agent as a polymerization initiator can be used in combination with a metal salt. The metal salt is not particularly limited, but a copper salt, a nickel salt, an iron salt, a cobalt salt, a chromium salt, and the like can be used, and examples thereof include cupric chloride and ferric sulfate. .
Depending on the polymerization conditions, when a reducing agent is used in combination with a metal salt, the polymerization reaction proceeds smoothly, and a polymer having high emulsion stability and high molecular weight may be obtained.

The water-in-oil cationic polymer emulsion obtained by (co) polymerization under the polymerization conditions using the special polymerization initiator system has a high molecular weight of the emulsion polymer and a low physical viscosity. There is no precipitation or re-agglomeration of the emulsion particles during storage, resulting in excellent dispersion stability and storage stability. Furthermore, the water-in-oil cationic polymer emulsion produced by the production method of the present invention has a significantly improved performance as compared with a polymer emulsion produced by a conventional production method, and has a papermaking retention improver and an improved drainage. It is suitable for use as an agent, a flocculant for industrial wastewater and a sewage excreta treatment and a dehydrating agent.

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. (Example 1) Isobar (manufactured by Exxon, isoparaffin) 56 as a hydrophobic organic liquid in a 2 liter beaker
0 g and sorbitan monolaurate 64 g as a nonionic surfactant were mixed to prepare an oil solution. Separately, 800 g of methacryloylethyltrimethylammonium chloride (80% aqueous solution) was dissolved in 128 g of ion-exchanged water in a 1-liter beaker to prepare an aqueous monomer solution. Using a homogenizer for the oil solution, 5000
The aqueous monomer solution was gradually added while stirring at rpm.
After the addition was completed, emulsification and dispersion were continued for 10 minutes to produce a monomer emulsion. The prepared monomer emulsion was charged in a 2-liter three-neck separable flask connected to a stirrer, a thermometer, and a nitrogen inlet tube, and nitrogen gas was bubbled at a flow rate of 1.5 liter / min for 120 minutes.
The monomer emulsion was degassed. Next, after maintaining the temperature of this monomer emulsion at a constant temperature of 40 ° C.,
As a polymerization initiator, 32 g of a 0.1% aqueous sodium formaldehyde sulfoxylate solution and 16 g of a 0.1% aqueous sodium sulfite solution were added to initiate polymerization. About 4
After an hour, the polymerization was completed, and a water-in-oil polymer emulsion was obtained.

Example 2 In a 2-liter beaker, 640 g of toluene as a hydrophobic organic liquid and 80 g of polyoxyethylene stearyl ether as a nonionic surfactant were mixed to prepare an oil liquid. Separately, in a 1 liter beaker, 350 g of dimethylaminoethyl methacrylate sulfate (80% aqueous solution) and acrylamide 2
80 g was dissolved in 208 g of ion-exchanged water to prepare an aqueous monomer solution. Using a homogenizer for the oil liquid,
While stirring at 5000 rpm, the aqueous monomer solution was gradually added. After the addition was completed, emulsification and dispersion were continued for 10 minutes to produce a monomer emulsion. The entire amount of the prepared monomer emulsion was charged into a 2-liter 3-neck separable flask connected to a stirrer, a thermometer and a nitrogen inlet tube, and nitrogen gas was bubbled at a flow rate of 1.5 liter / min for 120 minutes to remove the monomer emulsion. I noticed. Next, after maintaining the temperature of the monomer emulsion at a constant temperature of 40 ° C., 42 g of a 0.1% aqueous sodium sulfite solution was added as a polymerization initiator to initiate polymerization. After about 4 hours, the polymerization was completed, and a water-in-oil polymer emulsion was obtained.

Example 3 In a 2-liter beaker, 640 g of n-hexane as a hydrophobic organic liquid and 96 g of polyoxyethylene stearyl ether as a nonionic surfactant were mixed to prepare an oil liquid. Separately, 420 g of dimethylaminoethyl methacrylate hydrochloride (80% aqueous solution) and 224 g of acrylamide were dissolved in 192 g of ion-exchanged water in a 1-liter beaker to prepare an aqueous monomer solution. A monomer aqueous solution was gradually added to the oil solution while stirring at 5000 rpm using a homogenizer. After addition is completed, emulsification and dispersion are continued for 10 minutes,
A monomer emulsion was prepared. The entire amount of the prepared monomer emulsion was charged into a 2-liter 3-neck separable flask connected to a stirrer, a thermometer and a nitrogen inlet tube, and nitrogen gas was bubbled at a flow rate of 1.5 liter / min for 120 minutes to remove the monomer emulsion. I noticed. Next, after keeping the temperature of this monomer emulsion at a constant temperature of 35 ° C., 28 g of a 0.1% ferrous chloride aqueous solution was added as a polymerization initiator to initiate polymerization. After about 4 hours, the polymerization was completed, and a water-in-oil polymer emulsion was obtained.

(Example 4) In the same manner as in Example 3, the charged amount of ion-exchanged water at the time of preparing the aqueous monomer solution was changed to 178 g, and 2,2'-azobisisobutyronitrile was used as a polymerization initiator. The polymerization was started by adding 14 g of a 0.1% aqueous solution and 28 g of a 0.1% ferrous chloride aqueous solution to obtain a water-in-oil polymer emulsion.

(Example 5) In the same manner as in Example 3, the amount of charged ion-exchanged water at the time of preparing the aqueous monomer solution was 189.2 g.
To 0.1% cupric chloride only before the start of polymerization.
After the addition of g, 24 g of a 0.1% ferrous chloride aqueous solution was added as a polymerization initiator to initiate polymerization, thereby obtaining a water-in-oil polymer emulsion.

(Comparative Examples 1 and 2) A redox polymerization initiator consisting of ammonium persulfate alone was used as the polymerization initiator in the same manner as in Example 3 according to the amounts of the polymerization initiator and the amounts of distilled water shown in Table 1. To obtain a water-in-oil polymer emulsion. (Comparative Examples 3 to 5) In the same manner as in Example 3, ferrous chloride was added as a polymerization initiator and then ammonium persulfate was added in the same manner as in Example 3 based on the amount of the polymerization initiator and the amount of distilled water shown in Table 1. The operation was performed using the redox polymerization initiator thus obtained to obtain a water-in-oil polymer emulsion.

[0024]

[Table 1]

The polymerization yield, physical viscosity, 0.2% aqueous solution viscosity, weight average molecular weight (Mw), and emulsion state of the water-in-oil polymer emulsions obtained in Examples 1 to 5 and Comparative Examples 1 to 5 The results are shown in Table 2. The polymerization yield was measured by liquid chromatography, and the physical viscosity and the 0.2% aqueous solution viscosity were measured using a B-type rotational viscometer (Rotor No. 3, 30
rpm) at 30 ° C., and the weight average molecular weight is GPC
Was measured. In the emulsion state, the dispersibility and uniformity of the emulsion were visually evaluated.

[0026]

[Table 2]

Table 3 shows the results of storage stability tests of the polymer emulsions obtained in Examples 1 to 5 and Comparative Examples 1 to 5. In the test, the polymer emulsion was stored in a constant temperature bath at 40 ° C., the physical viscosity was measured with time, and the emulsion state was also evaluated with time.

[0028]

[Table 3]

In order to examine the performance of the polymer emulsions obtained in Examples 1 to 5 and Comparative Examples 1 to 5 as a polymer flocculant, a Nutsche test was performed on excess sludge.
Surplus sludge generated by biological treatment of pulp and paper wastewater (pH
7.0, SS concentration: 2.6%)
A 0.1% aqueous polymer solution of the polymer emulsion was added, and the mixture was stirred at 500 rpm using a stirrer with propeller blades.
The mixture was stirred for 0 second to form a floc. The aggregated slurry was subjected to a Nutsche test (100 mesh nylon filter cloth), and the amount of filtrate after 30 seconds was measured. further,
The obtained floc was centrifugally dehydrated (100 mesh nylon filter cloth, 3000 rpm, 1 minute), and the water content of the floc was measured. Table 4 shows the results.

[0030]

[Table 4]

As shown in Tables 2 to 4, the water-in-oil polymer emulsions obtained from Examples 1 to 5 according to the production method of the present invention have a higher molecular weight than Comparative Examples 1 to 5. It is also found that the emulsion is excellent in the dispersibility, uniformity and storage stability of the emulsion, and shows high aggregation performance as a polymer flocculant.

[0032]

According to the present invention, by carrying out (co) polymerization under polymerization conditions using a special polymerization initiator system which has not been used at all, an oil containing a high-molecular-weight emulsion polymer and having good storage stability can be obtained. A water-based cationic polymer emulsion can be produced. The water-in-oil cationic polymer emulsion obtained by the method of the present invention is a water-in-oil cationic polymer emulsion having good water solubility, dispersion stability and storage stability, and having a low physical viscosity. High performance for applications such as retention and drainage improvers for papermaking, flocculants and dehydrating agents for industrial wastewater and sewage and human waste treatment. In the present invention, a large problem in the conventional water-in-oil polymer emulsion in which storage stability is deteriorated by selecting polymerization conditions for increasing the molecular weight is solved, and both performance and storage stability are sufficiently satisfied. Therefore, its industrial utility value is great.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08F 4/06 C08F 4/06 20/60 20/60 (72) Inventor Mitsuru Utsuki 5-1 Ogimachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Showa (56) References JP-B-54-37986 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 20/34-20/36 C08F 20 / 60 C08F 120/24-120/36 C08F 120/60 C08F 220/34-220/36 C08F 220/60 C08F 2/32 C08F 4/04 C08F 4/06

Claims (1)

(57) [Claims] 1. The method of claim 1, wherein the cationic vinyl monomer represented by the following general formula (1) is homopolymerized in the presence of water, a hydrophobic organic liquid, a nonionic surfactant, When producing a water-in-oil polymer emulsion by copolymerizing with a monomer, a peroxide is not used as a polymerization initiator, and a reducing agent is used alone or with an azobis-based polymerization initiator and / or a metal salt. Used in combination, 5 to 3 per monomer
A process for producing a water-in-oil cationic polymer emulsion, characterized in that polymerization is started by adding 00 ppm. Embedded image (In the formula, A represents an oxygen atom or NH; hydroxyalkylene group and Z is C2-4 alkylene or a carbon of 1 to 4 carbon atoms; R ₁ is hydrogen or a methyl group; R ₂ is from 1 to 4 carbon atoms
Alkyl group, hydroxyalkyl group or benzyl group having 2 to 4 carbon atoms; R _3, R ₄ carbon atoms are each independently 1
X 4 represents an alkyl group having 2 to 4 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms; X ⁻ represents a salt-forming anion. )