JPH0753827A - W/o-type polymer emulsion and use thereof - Google Patents

Abstract

PURPOSE:To provide a W/O-type polymer emulsion composed of a specific polymer, a specific oil-soluble surfactant, water, a hydrophobic liquid and a phase-inversion promoting surfactant at specific ratios, having low shape-keeping viscosity and excellent water-solubility, dispersion stability and storage stability and useful as a yield-improving agent for paper-making, etc. CONSTITUTION:This W/O-type polymer emulsion is composed of (A) 25-50wt.% (based on the total emulsion) of a polymer containing one or more kinds of water-soluble vinyl monomers of the formulas I to III (R<1> is H or methyl; R<2> is H or 1-3C alkyl; R<3> is H or 1-8C alkyl; R<4> is R<1> or carboxyl; M is H, univalent to trivalent metal ion, etc.) as constituent units, (B) 30-50wt.% of water, (C) 10-30wt.% of a hydrophobic liquid such as n-paraffin, (D) 0.1-8wt.% of oil- soluble surfactants containing (i) one or more kinds of oil-soluble surfactants having an HLB of 2-6 and (ii) one or more kinds of oil-soluble surfactants having an HLB of 8-15 and (E) 0.1-8wt.% of a phase-inversion promoting surfactant such as polyoxyethylene lauryl ether. The particle diameter of the polymer in the emulsion is <=0.3mum.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention has good water-solubility, dispersion stability and storage stability, and low product viscosity, and is a retention aid and drainage improver for papermaking, industrial wastewater and sewage treatment. The present invention relates to a water-in-oil type polymer emulsion exhibiting high performance for applications such as flocculants and dehydrating agents.

[0002]

2. Description of the Related Art Conventionally, water-soluble polymers such as polyacrylamide and copolymers of acrylamide and other anionic vinyl monomers have been used as coagulating sedimentation agents for sludge generated by treatment of activated sludge in sewage and urine treatment. It has been used mainly in powder form as a dehydrating agent, as a paper-making agent for holding cellulose fibers or fine substances during paper-making, and as an agent for industrial wastewater treatment such as papermaking wastewater treatment and civil wastewater treatment. . Also, in recent years due to its easy handling,
It is being replaced by drugs in the form of water-in-oil emulsions.

Conventionally used HLB values are 3 to 6
The water-in-oil type polymer emulsion using only the hydrophobic surfactant as the emulsifier is less likely to cause phase inversion of the emulsion from the water-in-oil type to the oil-in-water type when used in an aqueous suspension. Since the water-soluble polymer is difficult to function, JP-A-6-6
As shown in 3-90537, it was necessary to add a phase inversion promoting surfactant such as polyoxyethylene alkyl ether or polyoxyethylene alkyl allyl ether.

However, this self-inverting water-in-oil type polymer emulsion is deteriorated in dispersion stability and storage stability by adding a sufficient amount of a phase inversion-promoting surfactant to satisfy a sufficient phase inversion rate. After 2 to 3 weeks, the sedimentation of the polymer particles or the apparent viscosity of the emulsion increases, and within a few weeks at the latest, the polymer particles adhere to each other and become a gel that cannot be redispersed, and the fluidity characteristics as a liquid product are lost. There was a drawback that it would end up. One of the ways to solve the contradictory problem is to reduce the particle size of the polymer.

For example, Japanese Patent Application Laid-Open No. 2-225502 discloses that
A water-in-oil polymer having a particle size of 0.02 to 0.4 μm is obtained by polymerizing an aqueous solution of a water-soluble vinyl monomer and a hydrophobic liquid such as isoparaffin using a surfactant having an HLB value of 8 to 12. Methods for obtaining emulsions have been proposed. However, in order to reduce the particle size of the polymer, the ratio of the aqueous monomer solution to the hydrophobic liquid needs to be about 1: 1.
Therefore, only a water-in-oil emulsion having a low polymer concentration of 20% by weight or less is obtained.

On the other hand, the basic performance required when a water-in-oil type polymer emulsion is used as, for example, a polymer flocculant is to agglomerate solids suspended in water in the papermaking process, wastewater treatment process and the like. In order to achieve this object, how to make the polymer have a high molecular weight is a big problem.

However, in the case of a surfactant which has been usually used conventionally, when the polymerization is carried out under the condition of initiating the polymerization at a low temperature for increasing the molecular weight, the dispersion stability of the emulsion is deteriorated during the polymerization, and in the worst case, the dispersion is Gelation due to destruction will occur. Therefore, a method of heating the emulsion at a temperature of 45 ° C. or lower, first producing a small amount of a polymer, and then performing two-step polymerization at a temperature of 40 to 100 ° C. ing. But,
This method has a problem in that the polymerization initiation temperature becomes high, so that the polymer has a high molecular weight.

[0008]

The conventional water-in-oil type polymer emulsion has a monomer composition, a surfactant, a polymerization initiator,
Although various improvements have been made in terms of polymerization temperature conditions, etc., the above problems have not yet been solved, and a water-in-oil polymer emulsion satisfying both performance and storage stability during storage, and the use thereof There is a demand for a high-molecular flocculant. The present invention provides a water-in-oil polymer emulsion having good water solubility, dispersion stability, storage stability, and low product-state viscosity, and a retention aid and drainage improver for papermaking, industrial wastewater, and It is an object of the present invention to provide a water-in-oil type polymer emulsion showing high performance for applications such as a flocculant for treating sewage and urine.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve these problems, and as a result, have found that the oil-soluble surface active agents having an HLB of 2 to 6 which are conventionally used as emulsifiers. In addition to the agent, by using an oil-soluble surfactant having an HLB in the range of 8 to 15 at the same time, the emulsion can be dispersed even under the condition that a high-concentration monomer is polymerized at low temperature without heating. A water-in-oil polymer emulsion which is stable and has a particle size of the polymer in the emulsion of 0.3 μm or less and which contains a high-molecular weight polymer and has good storage stability, and can solve the above problems. Found,
The present invention has been completed.

That is, the present invention relates to a polymer containing as a constituent unit at least one of water-soluble vinyl monomers represented by the general formulas (A) to (C) in an amount of 25 to 50% by weight based on the total weight of the emulsion. Copolymer, 30-50% by weight of water,
A water-in-oil polymer emulsion comprising 10 to 30% by weight of a hydrophobic liquid, 0.1 to 8% by weight of an oil-soluble surfactant, and 0.1 to 8% by weight of a phase inversion promoting surfactant. A polymer containing a high molecular weight polymer containing at least one oil-soluble surfactant having an HLB of 2 to 6 and at least one oil-soluble surfactant having an HLB of 8 to 15 as the oil-soluble surfactant. Is a water-in-oil polymer emulsion having a particle size of 0.3 μm or less.

[0011]

[Chemical 4]

(R ¹ in the above formula is hydrogen or a methyl group, R 1
² represents hydrogen or an alkyl group having 1 to 3 carbon atoms, R ³
Represents hydrogen or an alkyl group having 1 to 8 carbon atoms. )

[0013]

[Chemical 5]

(R ⁴ in the above formula represents hydrogen, a methyl group or a carboxyl group, and M represents hydrogen, monovalent, divalent,
Represents a trivalent metal ion or ammonium ion. )

[0015]

[Chemical 6]

(M in the above formula represents hydrogen, monovalent, divalent or trivalent metal ion or ammonium ion.)

As the water-soluble vinyl monomer used in the present invention, (meth) acrylamide, N-methylacrylamide, N-isopropylacrylamide, N-butylacrylamide, Nt-octylacrylamide,
Nonionic monomers of N, N-dimethylacrylamide, N, N-diethylacrylamide, N, N-diisopropylacrylamide, and (meth) acrylic acid, itaconic acid or salts thereof, 2-acrylamido-2-methylpropanesulfone Examples thereof include anionic monomers such as acids or salts thereof.

The hydration degree of the anionic monomer is 50 to 100.
Mol%, preferably 70 to 100 mol%, and a degree of neutralization of 50 mol% or less is not preferable in terms of water solubility, storage stability, aggregation performance and the like. As the counterion of the anionic monomer, ammonia, amines such as dimethylamine,
It can be arbitrarily selected from alkali metals such as Na ⁺ and K ⁺ , alkaline earth metals such as Ca ²⁺ and Mg ²⁺ , Al ³⁺ and Fe ³⁺ .

If the weight ratio of the water-soluble vinyl polymer to the total weight of the emulsion is less than 25% by weight, the economy is poor,
It is difficult to manufacture a product with more than 50% by weight,
The product has a high viscosity and is difficult to handle.

The HLB used in the present invention is from 2 to 2.
The oil-soluble surfactant of 6 and the oil-solubility of the oil-soluble surfactant having an HLB of 8 to 15 mean that 10 parts by weight of the surfactant are added to 90 parts by weight of the hydrophobic liquid at a temperature of 25 ° C. When mixed, the surfactant is uniformly dissolved and white turbidity or separation does not occur.

Examples of the oil-soluble surfactant having an HLB of 2 to 6 include sorbitan monostearate, sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate and other sorbitan fatty acid esters, stearic acid monoglyceride, oleic acid monoglyceride, Glycerin fatty acid ester such as stearic acid monodiglyceride, oleic acid monodiglyceride or a mixture of two or more thereof, polyglycerin fatty acid ester such as decaglycerin pentaoleic acid, propylene glycol monostearate, propylene glycol fatty acid ester such as propylene glycol monooleate And the like, fatty acid esters of polyhydric alcohols such as those shown here.

As the oil-soluble surfactant having an HLB of 8 to 15, polyoxyethylene sorbitan monolaurate,
Polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan trioleate, etc. polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol tetraoleate, polyoxyethylene sorbitol tetraoleate, etc. Examples thereof include polyoxyethylene derivatives represented by ethylene sorbitol fatty acid esters and the like, and fatty acid esters of polyhydric alcohols represented by hexaglycerin monooleate, decaglycerin monooleate, decaglycerin monostearate and the like.

The mixing ratio of the oil-soluble surfactant having HLB of 2 to 6 and the oil-soluble surfactant having HLB of 8 to 15 is
It must be in the range 5: 1 to 1:10, preferably in the range 2: 1 to 1: 6. When the ratio of the oil-soluble surfactant having an HLB of 8 to 15 with respect to the oil-soluble surfactant having an HLB of 2 to 6 is lower than 5: 1, the emulsion is liable to be broken at the time of polymerization, and addition is performed after the completion of the polymerization. The reversible surfactant causes the polymer particles to easily settle, re-aggregate and thicken during storage.

Similarly, when the ratio of the oil-soluble surfactant having an HLB of 8 to 15 with respect to the oil-soluble surfactant having an HLB of 2 to 6 is higher than 1:10, the emulsion is broken during the polymerization. It will be easier. On the other hand, if the weight ratio of the oil-soluble surfactant to the total weight of the emulsion is less than 0.1% by weight, dispersion breakage of the emulsion occurs during polymerization and no emulsion is obtained, and if it exceeds 8% by weight, the economy is poor.

In the present invention, the addition amount of the phase inversion promoting surfactant is based on the total weight of the emulsion.
It is 0.1 to 8% by weight, preferably 0.5 to 5% by weight. If the phase inversion promoting surfactant is less than 0.1% by weight, sufficient water solubility cannot be obtained, and if it is 8% by weight or more, dispersion stability and storage stability are deteriorated, and polymer particles stick to each other, and It becomes a non-dispersible gel and loses its fluidity as a liquid product. Examples of the reversible surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene alkyl ether such as polyoxyethylene oleyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether and the like. Examples thereof include polyoxyethylene alkyl allyl ether.

Examples of the hydrophobic liquid include kerosene, light oil, kerosene, n-paraffin, isoparaffin, naphthene, cyclohexane, n-hexane, n-octane, isooctane, benzene, toluene, xylene and ligroin. A cyclic or aromatic hydrocarbon or the like can be used alone or in combination.

In the present invention, the polymerization initiator for polymerizing the vinyl monomer may be a commonly used radical polymerization initiator, such as benzoyl peroxide, lauroyl peroxide, potassium persulfate, ammonium persulfate and peroxide. Peroxides such as hydrogen oxide, or redox catalysts obtained by combining them with a reducing agent such as sodium sulfite, ferrous sulfate and dimethylaniline, 2,2-azobis (2-aminodipropane) hydrochloride (V-50) And azo compounds such as azobisisobutyronitrile and azobisvaleronitrile. Furthermore, ultraviolet light without using these polymerization initiators,
A method of initiating radical polymerization using radiation or the like can also be used.

In the present invention, the particle size of the aqueous phase polymer particles in the polymer emulsion is 0.3 μm or less. It is more preferable to form a stable water-in-oil type monomer emulsion having a polymerization average particle size of 0.3 μm or less before the polymerization. Generally, by making the monomer emulsion before polymerization fine, the polymer emulsion after polymerization can also be made into uniform and fine particles.

The weight average particle diameter of the monomer emulsion is set to 0.
As a method of reducing the thickness to 3 μm or less, a water-soluble vinyl polymer,
A method of giving a strong shearing force to a mixed solution of water, a hydrophobic liquid and an oil-soluble surfactant by using a device such as a homogenizer or an in-line homomixer is preferable. At this time, it is necessary to give an average circulation number (an average value of the number of times the liquid passes between the blade and the outer wall) of a certain number or more.
Therefore, in the present invention, the above oil-soluble surfactant is used,
Give sufficient shearing force before the start of polymerization, particle size 0.3μm
By forming the following stable water-in-oil type monomer emulsion, the polymerization is initiated at a low temperature of 5 to 25 ° C., and the high molecular weight and the particle size of the polymer particles is 0.3 μm.
It is possible to obtain a water-in-oil type polymer emulsion having m or less, which is excellent in dispersion stability, storage stability and water solubility.

The yield improver and drainage improver for papermaking according to the present invention, the coagulant for industrial wastewater and the treatment of sewage and sewage, and the chemical agent utilizing the cohesive action for civil engineering wastewater treatment include
The water-in-oil type polymer emulsion of the present invention is the main component, and the performance is remarkably improved as compared with the conventional polymer flocculant, such as precipitation and re-aggregation of emulsion particles during storage. In addition, it is excellent in storage stability, water solubility, and has a sufficiently high molecular weight, and is suitable for the above-mentioned applications.

[0031]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

(Example 1) In a 2 L beaker, 330 g of Isopar M (Exxon, isoparaffin) as a hydrophobic organic liquid, 15 g of sorbitan monooleate as a water-in-oil type surfactant, and 40 g of polyoxyethylene sorbitan monostearate. Were mixed to prepare an oil solution. Separately, 135 g of acrylic acid and 315 g of acrylamide were dissolved in 505 g of distilled water in a 1 L beaker and neutralized with 130 g of sodium hydroxide (40% by weight aqueous solution) to prepare a monomer aqueous solution. Using a homogenizer for the oil solution, the monomer aqueous solution was gradually added while stirring at 8000 rpm. After the addition was completed, emulsion dispersion was continued for 30 minutes (average circulation number: 500 passes) to prepare a monomer emulsion. A 2 L 3-neck separable flask, which was continuously equipped with a stirrer, a thermometer and a nitrogen introducing tube, was charged with the whole amount of the prepared monomer emulsion, and nitrogen gas was bubbled at a flow rate of 1.5 L / min for 60 minutes to obtain a monomer. The emulsion was degassed.

Next, the temperature of this monomer emulsion is set to 1
After cooling to 5 ° C., 0.5% 2,2-as a polymerization initiator
Azobis (2-aminodipropane) hydrochloride (V-50)
5 g of aqueous solution, 14 g of 0.1% ammonium persulfate aqueous solution
And 8 g of a 0.1% ferrous sulfate aqueous solution were sequentially added to initiate polymerization in an adiabatic system. After the polymerization was completed in about 2 hours, 30 g of polyoxyethylene oleyl ether was added as a reversible surfactant, and a water-in-oil polymer emulsion having a particle diameter of 0.15 μm or less (measured by a light scattering method) was used. Got

(Examples 2 to 5) Polymerization was carried out in the same manner as in Example 1 except that the composition of the hydrophobic liquid, water-in-oil type surfactant, monomer and the like and the polymerization initiator were changed to carry out polymerization. A water-in-water polymer emulsion was obtained.

(Comparative Example 1) The composition of the water-in-oil type surfactant was changed in the same manner as in the polymerization conditions of Example 1 so that the particle size of the polymer emulsion after polymerization was not within the range of the present invention. A combined emulsion was obtained.

Comparative Example 2 The homogenizer rotation speed and emulsification time were set to 3000 in the same manner as in the polymerization conditions of Example 1.
When the rpm was changed to 10 minutes (average circulation number: about 60 passes), a polymer emulsion having a particle size of the polymer emulsion after polymerization outside the range of the present invention was obtained. Composition ratio of these water-soluble vinyl monomer, water, hydrophobic liquid, oil-soluble surfactant with HLB of 2 to 6, oil-soluble surfactant with HLB of 8 to 15, polymerization initiator, and polymer emulsion. The particle sizes of are also shown in Table 1.

[0037]

[Table 1]

Next, the polymerization yield, the apparent viscosity, the viscosity of a 0.2% aqueous solution, the polymerization average molecular weight (Mw), and the emulsion state of the polymers obtained in Examples 1 to 5 and Comparative Examples 1 and 2 were determined. 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 B.
Type rotary viscometer (rotor NO.3, 30rpm) at 30 ℃
The weight average molecular weight was measured by GPC. As for the emulsion state, the dispersibility and uniformity of the emulsion were visually evaluated.

[0039]

[Table 2]

Next, in order to examine the storage stability of each polymer emulsion obtained in Examples 1 to 5 and Comparative Examples 1 and 2, each polymer emulsion was placed in a constant temperature bath at 40 ° C. for 60 days immediately after production. The solid viscosity and emulsion state were measured over time. Table 3 shows the results of these storage stability measurements.

[0041]

[Table 3]

As shown in Tables 2 and 3, the water-in-oil type polymer emulsions of Examples 1 to 5 prepared according to the production method of the present invention were converted into the water-in-oil type polymer emulsions of Comparative Examples 1 and 2. It can be seen that, in comparison, the emulsion has a high molecular weight, is excellent in dispersibility of the emulsion, storage stability over time, and water solubility, and has a low product viscosity.

Example 6 Pulp slurry (NBKP,
A slurry was prepared by adding 10% titanium oxide to the pulp solid content as a filler to a concentration: 0.5%, CSF: 210 ml). After adjusting 1500 mL of this slurry to pH 4.5 with sulfuric acid, Examples 1 to 5 and Comparative Examples 1 and 2 were performed.
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 60 seconds at 500 rpm using a stirrer with a propeller blade to form flocs. 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. The results are shown in Table 4.

[0044]

[Table 4]

(Example 7) Excess sludge (pH 5.8, SS concentration: 2.0) generated by biological treatment of paper pulp wastewater
%) Of 200 ml, Examples 1-5, Comparative Example 1,
A 0.1% aqueous solution of a polymer flocculant consisting of the polymer emulsion obtained in 2 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) was performed, and the filtrate after 30 seconds was measured. Further, the obtained flocs were centrifugally dehydrated (1
00, mesh nylon filter cloth, 3000 rpm) and the water content of the flocs were measured. The results are shown in Table 5.

[0046]

[Table 5]

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

[0048]

The water-in-oil type polymer emulsion of the present invention is obtained by polymerizing at least one water-soluble vinyl monomer in the presence of water, a hydrophobic liquid, and a water-in-oil type emulsifier, and then reversing the interface. Particle size of a polymer obtained by adding an active agent, which has a specific polymer concentration, a hydrophobic liquid concentration, a water-in-oil emulsifier and its concentration, and a reversible surfactant concentration and is a dispersed phase. It is a water-in-oil type polymer emulsion having a particle size of 0.3 μm or less, and has good dispersion stability, storage stability, and water solubility, and has a low product viscosity.

The water-in-oil type polymer emulsion of the present invention can be easily produced by giving sufficient shearing force before the initiation of the polymerization to initiate the polymerization. The polymer flocculant mainly composed of the water-in-oil type polymer emulsion of the present invention,
An unprecedented ultrafine particle size polymer emulsion, which has excellent storage stability and water solubility, and has a sufficiently high molecular weight. It is a retention aid and drainage improver for papermaking, industrial wastewater. It exhibits higher performance than conventional agents for applications such as coagulants and sewage and sewage treatment flocculants and dehydrating agents. In the present invention, it is possible to solve the big problem in the conventional water-in-oil polymer emulsion that the dispersion stability and the storage stability are deteriorated when the polymerization conditions for increasing the molecular weight are selected, and the performance, the storage stability and the water stability are improved. Since the solubility can be sufficiently satisfied, its industrial utility value is great.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C08F 220/58 MNG // D21H 17/37

Claims (4)

[Claims] 1. 25 to 5 relative to the total weight of the emulsion
A polymer containing 0% by weight of at least one water-soluble vinyl monomer represented by any one of the general formulas (A) to (C) as a constituent unit.
0-50% by weight water, 10-30% by weight hydrophobic liquid,
0.1-8% by weight of oil-soluble surfactant and 0.1-8
What is claimed is: 1. A water-in-oil type polymer emulsion comprising wt% phase inversion promoting surfactant, wherein HL is used as the oil soluble surfactant.
B is 2 to 6 and at least one kind of oil-soluble surfactant;
A water-in-oil type polymer emulsion, wherein LB contains at least one oil-soluble surfactant having 8 to 15 and the particle size of the polymer is 0.3 μm or less. [Chemical 1] (R ¹ in the above formula represents hydrogen or a methyl group, R ² represents hydrogen or an alkyl group having 1 to 3 carbon atoms, and R ³ represents hydrogen or an alkyl group having 1 to 8 carbon atoms.) (R ⁴ in the above formula represents hydrogen, a methyl group or a carboxyl group, and M represents hydrogen, a monovalent, divalent or trivalent metal ion, or an ammonium ion.) (M in the above formula represents hydrogen, monovalent, divalent, trivalent metal ion, or ammonium ion.) 2. An oil-soluble surfactant having an HLB of 2 to 6,
The weight ratio of the oil-soluble surfactant having an HLB of 8 to 15 is 5:
The water-in-oil polymer emulsion according to claim 1, which is in the range of 1 to 1:10. 3. The oil-soluble surfactant having an HLB of 2 to 6 is a fatty acid ester of glycerin, sorbitol, sorbitan, and polyglycerin, and the oil-soluble surfactant having an HLB of 8 to 15 is a polyester of sorbitol or a sorbitan fatty acid ester. The water-in-oil polymer emulsion according to claim 1, which is an oxyethylene derivative and a polyglycerin fatty acid ester. 4. A retention aid for papermaking comprising the water-in-oil polymer emulsion according to claim 1 as a main component, a drainage improver, a coagulant for industrial wastewater and sewage urine treatment, and civil engineering wastewater treatment. Use as a drug that utilizes the aggregating action.