JP6423700B2 - Method for producing polymer flocculant - Google Patents

Description

  The present invention relates to a method for producing a polymer flocculant. More specifically, the present invention relates to a method for producing a water-in-oil emulsion polymer flocculant having a small amount of coagulum which is an aggregate generated during polymerization and excellent in storage stability.

  Polymer flocculants are used to agglomerate, settle and separate suspensions contained in domestic wastewater and industrial wastewater, and as a yield improver in the paper industry and as an admixture and a mudifier in civil engineering. It is used. The polymer flocculant has nonionic, anionic, cationic, and amphoteric ionic properties. Which ionic agent is used depends on the properties of the water to be treated and the treatment method. Among these, nonionic and anionic ionic polymer flocculants are used to coarsely floculate particles condensed by charge neutralization with inorganic or organic coagulants, and yield improvers. It is used as a scouring agent.

On the other hand, polymer flocculants include powders, water suspensions of salted-out polymer particles called dispersions, and water-in-oil emulsions. When using a polymer flocculant, it is normal to dilute and dissolve the polymer in water, and the water-in-oil emulsion has excellent solubility and does not generate dust like powder. Yes, it is widely used.

  A water-in-oil emulsion is obtained by radical polymerization of an emulsion in which an aqueous monomer solution is dispersed in a hydrocarbon oil with a surfactant. As described in Patent Document 1 and Patent Document 2, a nonionic surfactant is mainly used for emulsification, and a surfactant having a low HLB value is used with emphasis on the polymerization stability of the emulsion. In addition to being relatively large and having a large specific gravity difference from oil, there is a problem that the gel particles containing the polymer settle and separate when stored for a long period of time, causing troubles during use.

Moreover, in order to dissolve the emulsion quickly in water, it is necessary to add a surfactant having a high HLB value called a phase inversion agent to the product, but if the HLB value at the time of polymerization is low, it is necessary to add a large amount. Therefore, there is a problem that the cost increases.

Patent Document 3 describes that it is preferable to use a nonionic surfactant and an ionic surfactant in combination from the viewpoint of emulsion stability, but the examples are single emulsifiers and the HLB value of the emulsifier. There is no description about. Moreover, although patent document 4 has a proposal of microemulsion with a small particle diameter in order to improve stability, there exists a fault that the quantity of an emulsifier is large and manufacturing cost is high and cannot make high concentration. Furthermore, in Patent Document 4, there are examples of a plurality of nonionic surfactants, but there is no description regarding the HLB value of the emulsifier. Accordingly, there is still room for improvement in the long-term separation stability of nonionic or anionic water-in-oil emulsion polymer flocculants that can be produced at low cost while maintaining polymerization stability.

JP 63-90510 A Japanese Patent No. 4198252 Japanese Patent No. 4382533 Japanese Patent No. 2676483

An object of the present invention is to provide a method for producing a nonionic or anionic water-in-oil emulsion polymer flocculant that solves long-term separation stability, exhibits good polymerizability, and has low coagulum and insoluble content. That is.

As a result of diligent investigations, the present inventors have found that nonionic or anionic water-in-oil obtained by emulsion polymerization by blending surfactants having different HLB values at a ratio where the weighted average HLB value is a specific value. The present invention was completed by finding that the type emulsion improves long-term separation stability and exhibits good polymerizability.

That is, the present invention
(1) A monomer mixture that does not contain a cationic monomer but contains a nonionic monomer and / or an anionic monomer is mixed with two or more surfactants having different HLB values to form each interface. A polymer flocculant comprising a polymer obtained by water-in-oil emulsion polymerization in the presence of a surfactant adjusted to have a weighted average HLB value of the activator of 4.0 to 8.0. It is a manufacturing method.

(2) Water-in-oil emulsion polymerization of the monomer mixture in the presence of at least a surfactant having an HLB value in the range of 1.5 to 7.0 and a surfactant having an HLB value in the range of 10 to 17. It is a manufacturing method of the polymer flocculant as described in said (1) containing the polymer obtained by this.

(3) The method for producing a polymer flocculant according to (1) or (2) above, wherein the monomer mixture contains a radically polymerizable bifunctional monomer.

(4) The method for producing a polymer flocculant according to (3), wherein the bifunctional monomer is one or more of methylenebisacrylamide or di (meth) acrylate represented by the following general formula (1): It is.
_{CH 2 = CR 1 -CO-X} -CO-CR 2 = CH 2 (1)
(In the formula, R ₁ and R ₂ represent H or CH ₃ , X represents O (C ₂ H ₄ O) l, O (C ₃ H ₆ O) l (l represents an integer of 1 to 20). Or an ethylene oxide-modified bisphenol A skeleton of the following general formula (2) or an ethylene oxide-modified isocyanuric acid skeleton of the following general formula (3).

(In the formula, R ₃ and R ₄ represent H or CH ₃ , and m and n represent an integer of 1 to 10.)

(In the formula, p, q and r represent an integer of 1 to 10.)

(5) The nonionic monomer is (meth) acrylamide, and the anionic monomer is (meth) acrylic acid (salt) and / or 2-acrylamido-2-methylpropanesulfonic acid (salt). The method for producing a polymer flocculant according to any one of (1) to (4).

(6) The method for producing a polymer flocculant according to any one of (1) to (5), wherein the standard viscosity of the water-in-oil emulsion polymer is 1 to 9 mPa · s. Here, the standard viscosity means a viscosity of a 1N sodium chloride solution in which 0.1% by mass of a polymer is dissolved, measured with a B-type viscometer using a BL adapter at 60 rpm and 25 ° C. .

(7) A polymer flocculant comprising the water-in-oil emulsion according to any one of (1) to (6).

The polymer flocculant obtained by the production method of the present invention is excellent in long-term separation stability, exhibits good polymerizability, and is nonionic or anionic oil free of coagulum or insoluble matter that causes product defects. Water-type emulsion polymer flocculant.

Further, the polymer flocculant of the present invention is a coagulation of domestic wastewater and industrial wastewater sludge, as a dehydrating agent, such as a drainage yield improver for papermaking, a drainage improver, a formation forming aid and a paper strength enhancer. It can be applied to a wide range of applications such as papermaking chemicals, flocculants for drilling and muddy water treatment, additives for increasing crude oil production, organic coagulants, thickeners, dispersants, scale inhibitors, antistatic agents, and fiber treatment agents. Is possible.

Hereinafter, the present invention will be described in detail.
Nonionic monomers and anionic monomers in the present invention are exemplified below. In the present specification, acrylate and / or methacrylate is represented as (meth) acrylate, acrylamide and / or methacrylamide is represented as (meth) acrylamide, and acrylic acid and / or methacrylic acid is represented as (meth) acrylic acid. Moreover, an acid and its salt are represented as an acid (salt).

Nonionic monomers include (meth) acrylamide compounds (meth) methacrylate (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hydroxyethyl (meth) acrylate, ) Alkyl acrylate ester, styrene, acrylonitrile, vinyl acetate and the like. Among these nonionic monomers, (meth) acrylamide is preferred because it is easy to increase the molecular weight required as a polymer flocculant and has excellent performance as a polymer flocculant. Most preferred is acrylamide, which is particularly excellent in performance as a molecular flocculant. These nonionic monomers may be used alone or in combination of two or more.

Examples of the anionic monomer include vinyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, maleic acid and the like and salts thereof in addition to (meth) acrylic acid and salts thereof. Among these anionic monomers, (meth) acrylic acid and salts thereof are preferable because the high molecular weight necessary for the polymer flocculant is easy and the performance as the polymer flocculant is excellent. As the salts, ammonium salts and alkali metal salts such as sodium salts and potassium salts are preferable. These anionic monomers may be used alone or in combination of two or more. There is no restriction | limiting in particular in the compounding ratio (molar ratio) of each monomer in the monomer mixture of this invention.

The bifunctional monomer used in the present invention is used for the purpose of introducing a branched or crosslinked structure into the polymer chain. Examples of the bifunctional monomer include methylene bisacrylamide and di (meth) acrylate represented by the following general formula (1). Furthermore, di (meth) modified with ethylene oxide and / or propylene glycol having high water solubility. An acrylate is mentioned. Among these, methylenebisacrylamide having a small molecular weight, water solubility and high reactivity is particularly preferable. Moreover, these bifunctional monomers may use 2 or more types together.
_{CH 2 = CR 1 -CO-X} -CO-CR 2 = CH 2 (1)
(Wherein R ₁ and R ₂ represent H or CH ₃ , X represents O (C ₂ H ₄ O) 1, O (C ₃ H ₆ O) 1, (l is an integer of 1 to 20) or An ethylene oxide-modified bisphenol A skeleton of the general formula (2) or an ethylene oxide-modified isocyanuric acid skeleton of the following general formula (3) is shown.

(In the formula, R ₃ and R ₄ represent H or CH ₃ , and m and n represent an integer of 1 to 10.)

(In the formula, p, q and r represent an integer of 1 to 10.)

  The amount of the bifunctional monomer is preferably in the range of 0 to 1000 ppm, more preferably in the range of 0 to 500 ppm, based on the total mass of the nonionic and / or anionic monomer mixture. If the amount exceeds 1000 ppm, even if the obtained emulsion is dissolved in water, it only swells by absorbing water and does not completely dissolve, and the performance as a polymer flocculant is remarkably lowered.

Examples of the oil include paraffins, various mineral oils, mixtures thereof, and hydrocarbon compounds such as n-hexane, cyclohexane, and n-heptane. The oil content is preferably 15 to 50% by mass based on the total amount of the water-in-oil emulsion.

From the viewpoint of improving the separation stability while imparting the polymerization stability of the emulsion, the surfactant in the present invention is a mixture of two or more surfactants having different HLB values, and the HLB value of each surfactant. Are adjusted so that the weighted average is in the range of 4.0 to 8.0. In particular, it is preferable to combine a surfactant having an HLB value of 1.5 to 7.0 and a surfactant having an HLB value of 10 to 17 so that the weighted average of the HLB values is 4.0 to 8.0.

The reason for this is that by combining two or more types of surfactants with different HLB values, the surfactant layer existing at the particle interface of the emulsion particles becomes thick, and the stability as an emulsion is estimated to be improved. ing.

Here, the HLB value indicates the molecular weight of the hydrophilic group portion in the total molecular weight of the surfactant, and the nonionic surfactant is obtained by the Griffin equation shown in the following general formula (4). It is what The HLB value of the mixed surfactant composed of two or more kinds of nonionic surfactants can be obtained as follows. The HLB value of the mixed surfactant is a load-averaged HLB value of each nonionic surfactant based on the blending ratio.

Mixed HLB = Σ (HLB _X × W _X ) / ΣW _X (4)
(In General formula (4), HLB _X shows the HLB value of the nonionic surfactant X.
W _X represents the mass (g) of the nonionic surfactant X having a value of HLB _X. )

  Examples of surfactants used include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, isostearyl glyceryl ether, glycerol monooleate, Sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, sorbitan monolaurate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitol tetraoleate, polyethylene glycol monooleate, polyethylene glycol dioleate Oleic acid diethanolamide, lauric acid monoethanolamide, stearic acid monoe It can be mentioned nonionic surfactants such as Noruamido. The effective addition amount of these surfactants is preferably 0.2 to 15% by mass, more preferably 0.25 to 10% by mass, based on the total amount of the water-in-oil emulsion.

  The polymerization conditions are appropriately set according to the monomers and initiators used and the physical properties of the polymer. The polymerization temperature is preferably 0 to 100 ° C, more preferably 10 to 80 ° C. The monomer concentration is preferably 20 to 50% by mass and more preferably 25 to 45% by mass with respect to the total amount of the water-in-oil emulsion. The polymerization time is preferably 1 to 10 hours.

  Examples of the polymerization initiator include persulfates such as sodium persulfate and potassium persulfate, organic peroxides such as benzoyl peroxide, t-butyl hydroperoxide and paramentane hydroperoxide, 2,2′-azobis- ( Amidinopropane) hydrochloride, azobiscyanovaleric acid, 2,2′-azobisisobutyronitrile and 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide] and other azo And known compounds such as redox catalysts composed of combinations of hydrogen peroxide, persulfate, sodium bisulfite, ferrous sulfate and the like. These polymerization initiators may be used alone or in combination of two or more.

  As a method for adjusting the molecular weight, a known chain transfer agent can be used. Known chain transfer agents include thiol compounds such as mercaptoethanol and mercaptopropionic acid, reducing inorganic salts such as sodium sulfite, sodium bisulfite and sodium hypophosphite, alcohols such as ethanol and isopropyl alcohol, Examples include allyl compounds such as sodium rylsulfonate.

  After the polymerization, a hydrophilic surfactant called a phase inversion agent can be added to make the emulsion particles easily compatible with water and easily dissolved in water. Examples of the hydrophilic surfactant include a cationic surfactant and a nonionic surfactant having an HLB value of 9 to 17.

  In addition, additives such as a stabilizer, a pH adjuster, and an antioxidant may be added as long as the effects of the present invention are not impaired.

  The water-in-oil emulsion of the present invention preferably has a standard viscosity of 1 to 9 mPa · s. The standard viscosity refers to the viscosity of a 1N sodium chloride aqueous solution in which 0.1% of the polymer content is dissolved using a BL adapter with a B-type viscometer, measured at 60 rpm and 25 ° C. When the standard viscosity is higher than 9 mPa · s, the solubility of the polymer is poor, and the performance as a flocculant is remarkably lowered.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. The tests described in the examples were performed as follows.

(1) Polymerization stability If the stability is poor during polymerization, aggregates of emulsion particles are generated. This aggregate is called a coagulum. When the amount of coagulum is 0.2% by mass or less, the polymerization stability is good. The coagulum amount was measured by the following method.
About 20 g of the precisely weighed water-in-oil emulsion is filtered through a # 150 mesh stainless steel wire mesh. The emulsion on the wire mesh is washed away with a hydrocarbon oil in which 10% by weight of sorbitan sesquioleate is dissolved. Wipe off the oil with a paper towel and measure the weight of the residue on the wire mesh. (Residual mass / amount of emulsion subjected to filtration) × 100 = coagulum amount (mass%). The larger the amount, the worse the polymerization stability.

(2) Storage stability The following accelerated test is introduced as an index of the separation stability of the emulsion during storage. When this index is 20% by mass or less, the difference in solid content between the upper layer emulsion and the lower layer emulsion after about 3 months at room temperature corresponds to less than 2%, and the storage stability is good. Details are described below.
About 65-70 g of water-in-oil emulsion is precisely weighed in a glass centrifuge tube and centrifuged at 1310 g for 23 minutes. The obtained supernatant is discarded, and the amount of the emulsion residue remaining on the bottom is precisely weighed. (Residual mass / amount of emulsion subjected to centrifugation) × 100 = sedimented separation amount (mass%). The larger this amount, the worse the storage stability.

In a five-neck separable flask, weigh 12.1 g of sorbitan sesquioleate with an HLB value of 3.7, 4.0 g of oleic acid diethanolamide with an HLB value of 5.0, and 1.9 g of polyethylene glycol monooleate with an HLB value of 13.5. 236.7g of paraffin oil was added and dissolved to prepare an oil phase. The weighted average HLB value of the added surfactant was 5.0, which was 1.8% by mass of the entire water-in-oil emulsion.
28 mass% ammonia water was added to 640.0 g of 50 mass% acrylamide aqueous solution, and it adjusted to pH 6.0. To this was added 1.28 g of a 5% by weight aqueous solution of a chelating agent EDTA, 0.32 g of isopropyl alcohol, 2.0 g of an aqueous solution containing 0.008 g of t-butyl hydroperoxide as an initiator, and 28% by weight ammonia after adding ion-exchanged water. The pH was again adjusted to 6.0 with water and 98% by mass sulfuric acid to prepare a total of 719.9 g of aqueous phase. The monomer concentration was 32% by mass of the entire water-in-oil emulsion. While stirring the oil phase, the water phase was added, and the mixture was stirred at a high speed with a homogenizer to prepare a water-in-oil emulsion. A five-necked separable flask was equipped with a nitrogen gas blowing tube, a reflux condenser, and a thermometer, and degassing was started with nitrogen gas while stirring with a stirring blade. After sufficiently degassing, while supplying nitrogen gas, nitrogen gas containing 0.02 vol% of sulfur dioxide was further blown into the emulsion at a supply rate of 28.0 ml / min to initiate polymerization. After reaching 40 ° C. and maintaining this temperature for 2 hours, the supply amount of nitrogen gas containing sulfur dioxide is increased to 149.1 ml / min, and further maintained at 40 ° C. for 1 hour, and then containing nitrogen and sulfur dioxide. The nitrogen gas was stopped, and after the polymerization was completed, the weight average average HLB value of the total emulsifier contained in the emulsion was set to 10.0 as the hydrophilic surfactant, polyethylene glycol monooleate having an HLB value of 13.5. .8 g was added and mixed to prepare the water-in-oil emulsion of Example 1.
Hereinafter, polymerization was carried out in the same manner as in Example 1 except that the emulsifier species used in the polymerization, the ratio thereof, the monomer ratio, and the pH of the aqueous phase were changed as shown in Table 1, and in the oils of Examples 2 to 9 A water emulsion was prepared.

  Instead of 2.0 g of water in the aqueous phase, 2.0 g of an aqueous solution containing 0.0064 g of methylenebisacrylamide is added, and the emulsifier species and ratio used in the polymerization, the monomer ratio of the aqueous phase, and the pH of the aqueous phase are set. Polymerization and preparation were carried out in the same manner as in Example 1 except that the changes were made as shown in Table 2.

In Example 10, the methylenebisacrylamide aqueous solution was changed to 2.0 g of an aqueous solution containing 0.0064 g of polyethylene glycol diacrylate (trade name: Aronix M-240 manufactured by Toagosei Co., Ltd.), and the same as described in Table 2 except that it was changed to the formulation shown in Table 2. Was prepared by polymerization.

Polymerization was carried out in the same manner as in Example 10 except that methylenebisacrylamide was changed to 0.0032 g and the formulation shown in Table 2 was changed.

In Example 10, except that the methylenebisacrylamide aqueous solution was changed to 2.0 g of an acetone solution containing 0.0064 g of polypropylene glycol diacrylate (trade name: Aronix M-225 manufactured by Toagosei Co., Ltd.) and changed to the formulation shown in Table 2. Was polymerized and prepared in the same manner.

In Example 10, the methylenebisacrylamide aqueous solution was changed to 2.0 g of an acetone solution containing 0.0064 g of isocyanuric acid ethylene oxide-modified diacrylate (trade name: Aronix M-215 manufactured by Toagosei Co., Ltd.). Polymerization was carried out in the same manner except that the formulation was changed.

In Example 10, the aqueous methylenebisacrylamide solution was changed to 2.0 g of an acetone solution containing 0.0032 g of bisphenol A ethylene oxide-modified diacrylate (trade name: Aronix M-211B, manufactured by Toagosei Co., Ltd.), and changed to the formulation shown in Table 2. Polymerization was carried out in the same manner except for the above.

<Comparative Example 1>
In Example 1, polymerization was carried out in the same manner except that the emulsifier species used in the polymerization, the ratio thereof, the monomer ratio, and the pH of the aqueous phase were changed as shown in Table 1.

<Comparative example 2>
The polymerization was carried out in the same manner as in Example 1 except that the emulsifier species used in the polymerization, the ratio thereof, the monomer ratio, and the pH of the aqueous phase were changed as shown in Table 1, and the emulsion particles aggregated in the middle. The mixture could not be stirred and the polymerization was stopped.

<Comparative Example 3>
The polymerization was carried out in the same manner as in Example 1 except that the emulsifier species used in the polymerization, the ratio thereof, the monomer ratio, and the pH of the aqueous phase were changed as shown in Table 1, and the emulsion particles aggregated in the middle. Stirring was disabled and polymerization was stopped.

<Comparative example 4>
In Example 1, it prepared similarly except having changed the emulsifier seed | species used at the time of superposition | polymerization, its ratio, a monomer ratio, and pH of the aqueous phase as shown in Table 2.

Tables 1 and 2 list the measurement results of polymerization stability (coagulum) and storage stability (sedimentation separation) of the emulsions of Examples and Comparative Examples.

In Table 1 and Table 2, abbreviations indicate the following.
AM: acrylamide AMPS: 2-acrylamido-2-methylpropanesulfonic acid AcA: acrylic acid (a) sorbitan sesquioleate, HLB value 3.7
(B) Oleic acid diethanolamide, HLB value 5.0
(C) Polyoxyethylene monooleate, HLB value 13. 5
(D) Polyoxyethylene sorbitan monooleate, HLB value 10.0
Bifunctional monomer addition amount: ppm / other monomer mass

  As is apparent from the results, the water-in-oil emulsions of the examples have low coagulum during polymerization and high polymerization stability, while the ratio of the sedimented layer by centrifugation, which is a test for promoting long-term separation stability, is small. It indicates that the storage stability is high.

Claims (5)

A monomer mixture containing no nonionic monomer and / or anionic monomer without a cationic monomer, and at least two surfactants having an HLB value in the range of 1.5 to 7.0 And at least one surfactant having an HLB value in the range of 10 to 17 was mixed to adjust the weighted average of the HLB values of each surfactant to be in the range of 4.0 to 8.0. In the presence of a surfactant, a water-in-oil emulsion containing a polymer obtained by water-in-oil emulsion polymerization is obtained,
Next, a method for producing a polymer flocculant in which a hydrophilic surfactant is added to the water-in-oil emulsion,
The nonionic monomer comprises (meth) acrylamide, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hydroxyethyl (meth) acrylate, styrene, acrylonitrile, and vinyl acetate. At least one selected from the group,
The anionic monomer is at least one selected from the group consisting of (meth) acrylic acid, vinyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, maleic acid, and salts thereof. A method for producing a polymer flocculant.   The surfactant having the HLB value in the range of 1.5 to 7.0 is sorbitan sesquiolate and oleic acid diethanolamide, and the surfactant having the HLB value in the range of 10 to 17 is polyoxyethylene monooleate. A method for producing a polymer flocculant according to claim 1.   The method for producing a polymer flocculant according to claim 1 or 2, wherein the monomer mixture contains a radically polymerizable bifunctional monomer. The method for producing a polymer flocculant according to claim 3, wherein the bifunctional monomer is one or more of methylenebisacrylamide or di (meth) acrylate represented by the following general formula (1).
_{CH 2 = CR 1 -CO-X} -CO-CR 2 = CH 2 (1)
(In the formula, R ₁ and R ₂ represent H or CH ₃ , X represents O (C ₂ H ₄ O) l, O (C ₃ H ₆ O) l (l represents an integer of 1 to 20). Or an ethylene oxide-modified bisphenol A skeleton of the following general formula (2) or an ethylene oxide-modified isocyanuric acid skeleton of the following general formula (3).

(In the formula, R ₃ and R ₄ represent H or CH ₃ , and m and n represent an integer of 1 to 10.)

(In the formula, p, q and r represent an integer of 1 to 10.) The method for producing a polymer flocculant according to any one of claims 1 to 4 , wherein the standard viscosity of the water-in-oil emulsion polymer is 1 to 9 mPa · s (wherein the standard viscosity is 0.1 mass of the polymer). 1N sodium chloride aqueous solution in which% is dissolved is a B-type viscometer, which means a viscosity measured using a BL adapter at 60 rpm and 25 ° C.).