JP2671249B2 - Water-in-oil type cationic emulsion, its production method and use as a polymer flocculant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-in-oil type cationic emulsion, a method for producing the same, and its use as a polymer flocculant. More specifically, it has good water solubility, dispersion stability and storage stability. Water-in-oil type cationic emulsion with low viscosity and its production method, and its applications such as retention and drainage improving agents for papermaking, coagulants and dehydrating agents for industrial wastewater and sewage and urine treatment On the other hand, the present invention relates to a novel polymer flocculant containing the above water-in-oil type cationic emulsion, which exhibits high performance, as a main component.

[0002]

2. Description of the Related Art Conventionally, cationic polymer flocculants have been widely used for applications such as retention aids for papermaking and drainage improvers, flocculants for industrial wastewater and sewage treatment, and dehydrating agents. . These cationic polymer flocculants are generally homopolymers of cationic vinyl monomers or copolymers of these with other water-soluble vinyl monomers,
The product form was mainly a powdered polymer. on the other hand,
In recent years, a large number of water-in-oil type polymer emulsion type polymer flocculants have been proposed as product forms because of their easy handling. 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 for obtaining a water-in-oil polymer emulsion by emulsifying and dispersing 30 to 30% by weight of a surfactant has been proposed. JP-A-63-90510 includes a water-soluble vinyl monomer and a crosslinking agent. An aqueous solution and an organic dispersion medium containing a hydrophobic surfactant having an HLB value of 3 to 6 are mixed and then 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. And the like, and JP-B-51-47156 discloses a water-soluble and ethylenically unsaturated monomer aqueous solution 3
A water-in-oil emulsion consisting of 0 to 70% by weight of a hydrophobic liquid, a water-in-oil emulsifier with a concentration of 0.1 to 10% by weight, and a free radical initiator is prepared and heated to generate free radicals. There has been proposed a method of producing and polymerizing the monomer to obtain a polymer latex, which is used for concentrating and dewatering solids from sewage and industrial waste liquid.

However, the basic performance required when using a water-in-oil type polymer emulsion as, for example, a polymer flocculant is to flocculate the target suspended particles in a papermaking process, a wastewater treatment process, etc. To achieve this, how to increase the polymer molecular weight is a major issue. However, in the conventional water-in-oil type polymer emulsion, if the polymerization conditions for increasing the molecular weight are selected, the storage stability deteriorates, and sedimentation, re-aggregation, thickening, etc. of the polymer particles occur during storage, and There is a big problem that performance and water solubility are lowered, and it is difficult to sufficiently satisfy both performance and storage stability.

[0004]

The above-mentioned conventional water-in-oil type polymer emulsion has various improvements in the monomer composition, the surfactant composition, etc., but the above problems have not been solved yet, and the performance and the storage stability are stable. There is a strong demand for a water-in-oil type polymer emulsion having a good balance of properties, a method for producing the same, and a polymer flocculant using the same. The present invention is water-soluble, dispersion stability, good storage stability, and a low water-in-oil type cationic polymer emulsion having a low viscosity, a method for producing the same, and a retention aid and drainage improver for papermaking, An object of the present invention is to provide a novel polymer flocculant of water-in-oil type cationic polymer emulsion type showing high performance for applications such as flocculants and dehydrators for industrial wastewater and sewage treatment.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the conventional problems, and as a result, in the conventional water-in-oil type polymer emulsion, the weight average particle diameter of emulsion particles was reduced. However, most of the emulsion particles of the conventional water-in-oil type polymer emulsion have a weight average particle diameter of 1.0 μm or more, and those having a weight average particle diameter of 0.3 μm or less are not produced. It has been found that the above problems can be solved by using a water-in-oil type cationic polymer emulsion having emulsion particles having an ultrafine particle diameter, which has not been found in the past, and completed the present invention.

The invention of claim 1 of the present invention is a homopolymerization of a cationic vinyl monomer represented by the following general formula in the presence of water, a hydrophobic organic liquid and a nonionic surfactant, Or a water-in-oil polymer emulsion obtained by copolymerizing this with another water-soluble vinyl monomer, wherein (A) the concentration of the polymer is 20 to 70% by weight, and (B) the hydrophobic organic The concentration of the liquid is 10 to 50% by weight, the concentration of the (C) nonionic surfactant is 8% by weight or less, and the weight average particle diameter of the (D) polymer emulsion is 0.
It is a water-in-oil type cationic emulsion characterized by having a size of 3 μm or less. General formula;

[0007]

Embedded image

(Wherein A is an oxygen atom or NH; Z is an alkylene group having 1 to 4 carbon atoms or a hydroxyalkylene group having 2 to 4 carbon atoms; R ₁ is hydrogen or a methyl group; R ₂ is
Hydrogen or an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group having 2 to 4 carbon atoms or a benzyl group; R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms or a hydroxyalkyl having 2 to 4 carbon atoms; The group; X ⁻ represents an anion that forms a salt. )

According to the second aspect of the present invention, a cationic vinyl monomer represented by the following general formula is homopolymerized in the presence of water, a hydrophobic organic liquid and a nonionic surfactant, Alternatively, when a water-in-oil type polymer emulsion is copolymerized with this and another water-soluble vinyl monomer, a stable water-in-oil type monomer emulsion having a weight average particle size of 0.3 μm or less is prepared before the initiation of polymerization. A method for producing a water-in-oil type cationic polymer emulsion, which comprises initiating polymerization after formation. General formula;

[0010]

Embedded image

(Wherein A is an oxygen atom or NH; Z is an alkylene group having 1 to 4 carbon atoms or a hydroxyalkylene group having 2 to 4 carbon atoms; R ₁ is hydrogen or a methyl group; R ₂ is
Hydrogen or an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group having 2 to 4 carbon atoms or a benzyl group; R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms or a hydroxyalkyl having 2 to 4 carbon atoms; The group; X ⁻ represents an anion that forms a salt. )

A third aspect of the present invention is a polymer flocculant containing the water-in-oil polymer emulsion according to the first aspect as a main component.

Examples of the cationic vinyl monomer represented by the general formula used in the present invention include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate and dimethylaminohydroxypropyl (meth).
Neutralized salts or quaternary compounds of dialkylamino (hydroxy) alkyl (meth) acrylates such as acrylate, dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide,
Examples thereof include neutralized salts or quaternized salts of dialkylamino (hydroxy) alkyl (meth) acrylamides such as dimethylaminohydroxypropyl (meth) acrylamide.

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

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

Examples of the nonionic surfactant used in the present invention include polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan tristearate, polyoxyethylene lauryl ether, polyethylene glycol monooleate and sorbitan monolaurate. To be

In the present invention, the polymerization initiator for polymerizing the vinyl monomer may be a generally used radical polymerization initiator, such as a peroxide such as ammonium persulfate and hydrogen peroxide, or a peroxide thereof and sulfurous acid. Examples thereof include redox polymerization initiators in combination with reducing agents such as sodium, azo compounds such as azobisisobutyronitrile, and the like. Further, there is also a method of initiating radical polymerization by using ultraviolet rays, radiation or the like without using these polymerization initiators.

In the present invention, it is essential to form a stable water-in-oil type monomer emulsion having a weight average particle diameter of 0.3 μm or less before polymerization. Generally, by making the monomer emulsion before polymerization fine, the polymer emulsion after polymerization can also be made into uniform and ultrafine emulsion particles. Therefore, the polymer emulsion after polymerization has a high molecular weight, has good storage stability, and further has improved solubility in water. When the weight average particle diameter of the monomer emulsion exceeds 0.3 μm, it is difficult to obtain a polymer emulsion having a high molecular weight and good storage stability.

As a method for adjusting the weight average particle diameter of the monomer emulsion to 0.3 μm or less, the composition ratio of the monomer, water, the hydrophobic organic liquid and the nonionic surfactant and the hydrophobic organic liquid and the nonionic surfactant are used. It is needless to say that the selection of the type should be thoroughly examined, but it is necessary to apply an extremely strong shearing force to these mixed liquids. A device such as a homogenizer or an in-line homomixer is used as a means for giving a shearing force, and a sufficient average circulation number (the average number of times the liquid passes between the blade and the outer wall).
It is important to keep

As a method for measuring the weight average particle size of the monomer emulsion, a light scattering method, a centrifugal sedimentation light transmission method,
There are various measuring methods such as a laser diffraction method and an electric detection zone method, and a measuring instrument corresponding to each method has been devised, but the light scattering method is preferable from the viewpoint of measuring range and accuracy.

The weight average particle diameter of the emulsion particles of the polymer emulsion of the present invention is 0.3 μm or less.
When it exceeds 0.3 μm, it is difficult to sufficiently stabilize the polymer emulsion and increase the polymer molecular weight.
The polymer concentration in the polymer emulsion of the present invention is usually 20 to 70% by weight, preferably 30 to 50% by weight. When the concentration exceeds 70% by weight, it becomes very difficult to set the weight average particle diameter of the emulsion particles to 0.3 μm or less. Further, if the concentration is less than 20% by weight, it becomes difficult to sufficiently increase the molecular weight of the polymer. The concentration of the nonionic surfactant in the polymer emulsion of the present invention is usually 8% by weight or less, preferably 2 to 6% by weight. The concentration of the hydrophobic organic liquid in the polymer emulsion of the present invention is usually 10 to 50% by weight, preferably 25 to 40% by weight. When the concentration is less than 10% by weight, it becomes very difficult to set the weight average particle diameter of the emulsion particles to 0.3 μm or less. Further, even when the concentration exceeds 50% by weight, it becomes difficult to obtain a polymer emulsion having good storage stability.

The method for measuring the weight average particle diameter of the emulsion particles of the polymer emulsion of the present invention is the same as the method for measuring the weight average particle diameter of the above-mentioned monomer emulsion, such as a light scattering method, a centrifugal sedimentation light transmission method and a laser. There are various measurement methods such as the diffraction method and the electrical detection zone method, and measuring instruments corresponding to each method have been devised, but considering the measurement range and accuracy, the light scattering method is the most suitable. Seem.

The water-in-oil type cationic polymer emulsion of the present invention obtained by forming a monomer emulsion having an ultrafine particle size before the initiation of polymerization and then initiating the polymerization has uniform and fine particles, and therefore has a molecular weight of Is high,
It has low physical viscosity, does not cause precipitation or re-aggregation of emulsion particles during storage, and has excellent dispersion stability and storage stability.

The polymer flocculant of the present invention comprises the water-in-oil type cationic polymer emulsion of the present invention as a main component, and the performance is remarkably improved as compared with the conventional polymer flocculant, and the polymer flocculant is stored. Emulsion particles do not precipitate or re-aggregate during storage, have excellent storage stability and water solubility, and have a sufficiently high molecular weight. Therefore, they are retention aids for papermaking and drainage improvers, for industrial wastewater. It is also suitable for use as a flocculant and a dehydrating agent for treating sewage and urine.

[0025]

EXAMPLES The present invention will be specifically described with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. (Example 1) 640 g of n-hexane as a hydrophobic organic liquid and 80 g of polyoxyethylene stearyl ether as a nonionic surfactant were mixed in a 2 liter beaker to prepare an oil liquid. Separately, in a 1 liter beaker, dimethylaminoethyl methacrylate hydrochloride 36
0 g (80% aqueous solution) and 192 g of acrylamide were dissolved in 316 g of ion-exchanged water to prepare a monomer aqueous solution. 8000 using a homogenizer for the oil liquid
The monomer aqueous solution was gradually added while stirring at rpm. After the addition was completed, the emulsion dispersion was continued for 180 minutes (average circulation number:
3000 passes) to prepare a monomer emulsion. A 2-liter 3-neck separable flask connected with a stirrer, a thermometer and a nitrogen inlet tube was charged with the whole amount of the monomer emulsion prepared, 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, the temperature of this monomer emulsion is set to 3
After maintaining at a constant temperature of 5 ° C., 0.1 as a polymerization initiator
% Of an aqueous ferrous chloride solution and 14 g of 0.1% ammonium persulfate were sequentially added to initiate polymerization. Polymerization was completed after about 4 hours, and a water-in-oil type cationic polymer emulsion having a weight average particle diameter of 0.21 μm (measured by a light scattering method) was obtained.

(Examples 2 to 5) Further, by changing the composition of the hydrophobic organic liquid, the nonionic surfactant, the monomer and the like and the polymerization initiator in the same manner, polymerization is carried out to give water in oil. A type cationic polymer emulsion was obtained. Table 1 also shows their composition, polymerization initiator, weight average particle diameter of the monomer emulsion and weight average particle diameter of the polymer emulsion after polymerization.

[0027]

[Table 1]

(Comparative Example 1) In the same manner as the polymerization conditions of Example 1, the number of revolutions of the homogenizer and the emulsification time were changed,
A polymer emulsion was obtained in which the weight average particle size of the monomer emulsion and the weight average particle size of the polymer emulsion after polymerization were out of the range of the present invention. (Comparative Example 2) In the same manner as in the polymerization conditions of Example 3, the number of revolutions of the homogenizer and the emulsification time were changed, and the weight average particle diameter of the monomer emulsion and the weight average particle diameter of the polymer emulsion after polymerization were determined according to the present invention. A polymer emulsion out of range was obtained. (Comparative Example 3) By changing the number of revolutions of the homogenizer and the emulsification time in the same manner as in the polymerization conditions of Example 5, the weight average particle diameter of the monomer emulsion and the weight average particle diameter of the polymer emulsion after polymerization were determined according to the present invention. A polymer emulsion out of range was obtained. (Comparative Example 4) In the same manner as in the polymerization conditions of Example 1, the number of revolutions of the homogenizer, the emulsification time, the composition of the surfactant and the ion-exchanged water were changed, and the weight average particle diameter of the monomer emulsion and the polymer after polymerization were changed. A polymer emulsion having a weight average particle size of the emulsion outside the range of the present invention was obtained. (Comparative Example 5) In the same manner as in the polymerization conditions of Example 1, the number of revolutions of the homogenizer, the emulsification time, the composition of the surfactant and the ion-exchanged water were changed, and the weight average particle diameter of the monomer emulsion and the polymer after polymerization were changed. A polymer emulsion having a weight average particle size of the emulsion outside the range of the present invention was obtained. Table 2 shows the emulsification conditions / composition conditions, the weight average particle size of the monomer emulsion and the weight average particle size of the polymer emulsion of Comparative Examples 1 to 5.

[0029]

[Table 2]

Polymerization yields, physical viscosities of the polymer emulsions obtained in Examples 1 to 5 and Comparative Examples 1 to 5,
Table 3 shows the viscosity of 0.2% aqueous solution, weight average molecular weight (Mw), and emulsion state. The polymerization yield was measured by liquid chromatography. The physical viscosity and 0.2% aqueous solution viscosity were measured using a B-type rotational viscometer (rotor No. 3, 30 rp).
m) at 30 ° C., and the weight average molecular weight was measured by GPC. As for the emulsion state, the dispersibility and uniformity of the emulsion were visually evaluated.

[0031]

[Table 3]

Next, in order to examine the storage stability of each polymer emulsion obtained in Examples 1 to 5 and Comparative Examples 1 to 5, each polymer emulsion was prepared from 60 immediately after its production.
It was stored in a constant temperature bath at 40 ° C for a day, and the apparent viscosity and emulsion state were measured with time. Table 4 shows the results of these storage stability measurements.

[0033]

[Table 4]

As shown in Tables 3 to 4, the water-in-oil type polymer emulsions of Examples 1 to 5 prepared according to the production method of the present invention were compared with the water-in-oil type polymer emulsions of Comparative Examples 1 to 5. Has high molecular weight and dispersibility of emulsion,
It can be seen that it has excellent uniformity and storage stability, and has a low physical viscosity.

Example 6 Pulp slurry (NBKP,
A slurry was prepared by adding 10% titanium oxide to the pulp solids as a filler to a concentration of 0.5% and CSF of 210 ml. The pH of 1500 ml of this slurry was adjusted with sulfuric acid.
After adjusting to 4.5, a 0.1% aqueous solution of a polymer flocculant consisting of the polymer emulsions obtained in Examples 1 to 5 and Comparative Examples 1 to 5 was added, and the mixture was stirred at 500 rpm using a stirrer with a propeller blade. Stir for 60 seconds to allow flock formation. DDJ tester (TAPPI standard, 100
(500 mesh) using a mesh wire mesh)
The mixture was stirred at m 3 for 30 seconds and then filtered, and the SS concentration of the filtrate was measured. Table 5 shows the results.

[0036]

[Table 5]

Example 7 Pulp slurry (NBKP,
Concentration: 1.0%, CSF: 440 ml), a slurry was prepared by adding 20% of sodium bicarbonate to the pulp solid content as a filler. To 1000 ml of this slurry, a 0.1% aqueous solution of a polymer flocculant consisting of the polymer emulsions obtained in Examples 1 to 5 and Comparative Examples 1 to 5 was added, and the mixture was stirred at 500 rpm using a stirrer with a propeller blade.
Stir for 0 seconds to allow flock formation. The freeness of the agglomerated slurry was measured using a Canadian Standard Freeness Tester. Table 6 shows the results.

[0038]

[Table 6]

(Example 8) Excess sludge (pH 5.8, SS concentration: 2.0) generated by biological treatment of paper pulp wastewater
%) Of 200 ml, Examples 1-5, Comparative Examples 1-5
A 0.1% aqueous solution of a polymer flocculant consisting of the polymer emulsion obtained in 1. was added, and the mixture was stirred for 90 seconds at 500 rpm using a stirrer with a propeller blade to form flocs. The Nutsche test (1
00 mesh nylon filter cloth) and the amount of filtrate after 30 seconds was measured. Further, the resulting flocs were centrifugally dehydrated (100 mesh nylon filter cloth, 3000 rpm, 1
Min), and the water content of the floc was measured. Table 7 shows the results.

[0040]

[Table 7]

As shown in Tables 5 to 7, the water-in-oil type polymer emulsion type polymer flocculants according to the present invention are
It can be seen that, as compared with the polymer flocculant composed of the polymer emulsion of Comparative Example, it exhibits excellent performance for applications such as a retention improver for papermaking and a drainage improver, and a dehydrating agent for industrial wastewater.

[0042]

The water-in-oil type cationic emulsion of the present invention comprises a cationic vinyl monomer, water, a hydrophobic organic liquid,
Specific (A) polymer concentration, (B) concentration of hydrophobic organic liquid obtained by homopolymerization in the presence of a nonionic surfactant or by copolymerization thereof with another water-soluble vinyl monomer , (C) a nonionic surfactant concentration, and (D) the polymer emulsion has a weight average particle size of 0.
A water-in-oil type cationic emulsion having a particle size of 3 μm or less, which has good water solubility, dispersion stability, and storage stability,
It also has a low physical viscosity. To easily produce the water-in-oil type cationic emulsion of the present invention by forming a stable water-in-oil type monomer emulsion having a weight average particle size of 0.3 μm or less before starting the polymerization and then initiating the polymerization. You can The polymer flocculant containing the water-in-oil type cationic emulsion of the present invention as a main component has emulsion particles having an ultrafine particle diameter which has never been used, is excellent in storage stability and water solubility, and is sufficiently high. Higher performance than conventional polymer flocculants for applications such as retention aids and drainage improvers for papermaking, flocculants for industrial wastewater and sewage and sewage treatment, and dehydrating agents. Indicates. In the present invention, solving the big problem in the conventional water-in-oil polymer emulsion that the storage stability is deteriorated by selecting the polymerization conditions for increasing the molecular weight,
Since both performance and storage stability can be fully satisfied, its industrial utility value is great.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tadayoshi Hashimoto 5-1 Ogimachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Showa Denko KK Chemicals Research Laboratory (56) Reference JP-A-60-35002 (JP, A) JP 48-19632 (JP, A)

Claims (3)

(57) [Claims] 1. A cationic vinyl monomer represented by the following general formula is homopolymerized in the presence of water, a hydrophobic organic liquid or a nonionic surfactant, or with this and another water-soluble vinyl monomer. A water-in-oil polymer emulsion obtained by copolymerization, wherein the concentration of (A) polymer is 20 to 70% by weight, and the concentration of (B) hydrophobic organic liquid is 10 to 50% by weight. , (C) the concentration of the nonionic surfactant is 8% by weight or less, and (D) the weight average particle size of the polymer emulsion is 0.
A water-in-oil type cationic emulsion characterized by having a size of 3 μm or less. General formula; (In the formula, A is an oxygen atom or NH; Z is an alkylene group having 1 to 4 carbon atoms or a hydroxyalkylene group having 2 to 4 carbon atoms; R ₁ is hydrogen or a methyl group; R ₂ is hydrogen or 1 to 4 carbon atoms. the salt ^- X; alkyl group, a hydroxyalkyl group or a benzyl group having 2 to 4 carbon atoms; hydroxyalkyl group of the alkyl group or C2-4 1 to 4 carbon atoms in each of R _3, R ₄ independently Represents the anion that forms.) 2. A cationic vinyl monomer represented by the following general formula is homopolymerized in the presence of water, a hydrophobic organic liquid or a nonionic surfactant, or with this and another water-soluble vinyl monomer. When producing a water-in-oil type polymer emulsion by copolymerization, a stable water-in-oil type monomer emulsion having a weight average particle size of 0.3 μm or less is formed before the start of the polymerization, and then the polymerization is started. And a method for producing a water-in-oil type cationic polymer emulsion. General formula; (In the formula, A is an oxygen atom or NH; Z is an alkylene group having 1 to 4 carbon atoms or a hydroxyalkylene group having 2 to 4 carbon atoms; R ₁ is hydrogen or a methyl group; R ₂ is hydrogen or 1 to 4 carbon atoms. the salt ^- X; alkyl group, a hydroxyalkyl group or a benzyl group having 2 to 4 carbon atoms; hydroxyalkyl group of the alkyl group or C2-4 1 to 4 carbon atoms in each of R _3, R ₄ independently Represents the anion that forms.) 3. A polymer flocculant containing the water-in-oil polymer emulsion according to claim 1 as a main component.