JP2006089515A - Water-in-oil type dispersion having excellent stability and solubility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a water-in-oil type dispersion that contains a water-soluble polymer in an aqueous phase and has excellent stability and solubility, especially a water-in-oil type emulsion. <P>SOLUTION: The water-in-oil type dispersion essentially comprises a water-immiscible organic liquid, a water-soluble polymer-containing aqueous phase, an acid and a cationic oil-soluble polymer containing a hydrophobic group and a cationic group of specific structural units. The cationic oil-soluble polymer is preferably a copolymer of 50-95 mol% of a 4-18C alkyl group-containing alkyl (meth)acrylate and 5-50 mol% of a dialkylaminoalkyl (meth)acrylate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a water-in-oil dispersion that is stable and excellent in dissolution. More specifically, the present invention relates to a water-in-oil dispersion liquid that contains a water-immiscible organic liquid, an aqueous phase containing a water-soluble polymer, an acid and a cationic oil-soluble polymer as essential components and is excellent in stability and dissolution.

Technical background

Water-in-oil dispersions containing water-soluble polymers in the aqueous phase are easier to measure, dissolve and automate than powdered or highly viscous liquids. In particular, water-in-oil emulsions are excellent in handleability and are widely used as flocculating agents and thickeners.

These have problems such as water-soluble polymer particles adhering due to mechanical shear to generate foreign matter, separation and solidification by gravity, and time required for dissolution. Moreover, since these tendencies become particularly remarkable as the monomer concentration increases, it is difficult to obtain a high-quality high-concentration dispersion.

In Patent Document 1, an oil-soluble polymer having a charge opposite to that of the ionic water-soluble polymer in the aqueous phase is used as a suspension polymerization method including an ionic water-soluble polymer in the aqueous phase and for the purpose of stabilizing the product. A method to use is proposed. However, the stability of the product against the mechanical share is not sufficient, and since an oil-soluble polymer having an opposite charge to the ionic water-soluble polymer in the aqueous phase is used, When the ionic water-soluble polymer is dissolved, the dissolution may be inhibited.

Patent Document 2 describes a cationic oil-soluble composition comprising a hydrophobic monomer and a hydrophilic monomer for the purpose of producing a water-in-oil emulsion having an excellent water storage phase and containing an ionic water-soluble polymer in the aqueous phase. A polymer is added to the oil phase and dissolved together with the surfactant, and then mixed with an aqueous monomer solution to form a water-in-oil emulsion for polymerization. However, this method does not describe neutralization of cationic groups with an acid to improve dispersibility.

JP 59-47203 A British Patent No. 1,482,515

An object of the present invention is to obtain a water-in-oil dispersion, particularly a water-in-oil emulsion, which contains a water-soluble polymer in an aqueous phase and is excellent in stability under such circumstances. Here, when it is described as a water-in-oil dispersion, it refers to a dispersion having a water phase particle size of 0.5 to 500 μm, and when it is described as a water-in-oil emulsion, the water phase particle size is 0.1 to 500 μm. Refers to a 5 μm dispersion. Both are collectively referred to as a water-in-oil dispersion hereinafter.

一般式（１）
ここでＲ１は水素またはメチル基、Ｑはフェニル基、炭素数７〜１８のアリール基、アルキル基、ＣＯＯＲ３あるいはＣＯＮＨＲ４である。ここでＲ３、Ｒ４は炭素数４〜１８のアルキル基。Ｒ２は水素または炭素数１〜３のアルキル基。

一般式（２）
Ｒ７は水素又はメチル基、Ｒ８、Ｒ９は炭素数１〜３のアルキルあるいはアルコキシル基、Ｒ１０は水素、炭素数１〜３のアルキル基、アルコキシル基あるいはベンジル基であり、同種でも異種でも良い。Ａは酸素またはＮＨ、Ｂは炭素数２〜４のアルキレン基またはアルコキシレン基を表わす。Ｘ１は陰イオンを表わす。 As a result of intensive studies to achieve the above object, the present inventors have found that a water-immiscible organic liquid, an aqueous phase containing a water-soluble polymer, an acid, and a structure represented by the following general formulas (1) and (2) It has been found that by containing a cationic oil-soluble polymer having a unit as an essential component, a desired water-in-oil dispersion having excellent stability and dissolution can be obtained, and the present invention is completed based on this finding. It came. Further, with respect to the amino group in the molecule of the cationic oil-soluble polymer, the water-in-oil monomer dispersion before polymerization or the water-in-oil polymer dispersion after polymerization contains 30 mol% or more of acid. It is characterized by that.

General formula (1)
Here, R1 is hydrogen or a methyl group, Q is a phenyl group, an aryl group having 7 to 18 carbon atoms, an alkyl group, COOR3 or CONHR4. Here, R3 and R4 are alkyl groups having 4 to 18 carbon atoms. R2 is hydrogen or an alkyl group having 1 to 3 carbon atoms.

General formula (2)
R7 is hydrogen or a methyl group, R8 and R9 are alkyl or alkoxyl groups having 1 to 3 carbon atoms, and R10 is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, which may be the same or different. A represents oxygen or NH, and B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms. X1 represents an anion.

The present invention also relates to a method for using a water-in-oil dispersion, wherein the water-soluble polymer dispersion is used as an aggregating agent.

The present invention provides a water-in-oil dispersion that is stable and excellent in solubility, so that a water-immiscible organic liquid, an aqueous phase containing a water-soluble polymer, an acid, and a specific cationic group and a hydrophobic group And a cationic oil-soluble polymer having a structural unit as an essential component. The cationic oil-soluble polymer is preferably a copolymer of an alkyl (meth) acrylate having a C 4-18 alkyl group and a dialkylaminoalkyl (meth) acrylate. Further, the acid is added in an amount of 30 mol% or more to the water-in-oil monomer dispersion before polymerization or the water-in-oil polymer dispersion after polymerization with respect to the amino group in the molecule of the cationic oil-soluble polymer. It is preferable.

First, the cationic oil-soluble polymer will be described. The cationic oil-soluble polymer of the present invention can be produced by copolymerization of a hydrophobic monomer and a monomer having a cationic group. The hydrophobic monomer is a monomer having an aromatic ring such as styrene or α-methylstyrene or an aromatic ring to which an alkyl group is added, an aromatic ring having 6 to 20 carbon atoms such as an α-olefin, or an aliphatic vinyl compound. Moreover, the alkyl (meth) acrylate which has a C4-C18 alkyl group can also be used.

Specific examples of the alkyl (meth) acrylate include the following. That is, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, and the like.

The monomer having a cationic group is dialkylaminoalkylacrylamide or dialkylaminoalkyl (meth) acrylate. Specific examples of the dialkylaminoalkylacrylamide include dimethylaminopropylacrylamide and diethylaminopropylacrylamide. Specific examples of the dialkylaminoalkyl (meth) acrylate include dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl acrylate and the like.

Of these combinations of copolymerization of the hydrophobic monomer and the monomer having a cationic group, 2-ethylhexyl acrylate or lauryl acrylate and dimethylaminoethyl methacrylate are most preferable.

The molar ratio of the hydrophobic monomer in the cationic oil-soluble polymer is preferably 50 to 95 mol%, more preferably 50 to 80 mol%. On the other hand, the molar ratio of the monomer having a cationic group is preferably 5 to 50 mol%, more preferably 20 to 50 mol%.

The cationic oil-soluble polymer can be prepared by a conventional polymerization method after preparing the monomer mixture. Examples of the polymerization method include solution polymerization, bulk polymerization, and suspension polymerization. A preferred method is solution polymerization which is easy to handle and handle the polymerization. In the case of solution polymerization, the polymerization is performed at a monomer concentration of 20 to 80%, preferably 40 to 60%. In this case, the polymerization solvent is preferably a nonpolar organic solvent. That is, it is an aromatic or aliphatic hydrocarbon, and particularly preferred is paraffin or isoparaffin having a boiling point of 190 ° C. to 230 ° C. used as a dispersion medium in water-in-oil emulsion polymerization.

The method for using the cationic oil-soluble polymer of the present invention can be arbitrarily used. That is, after polymerizing the cationic oil-soluble polymer, an appropriate amount is added and dispersed in the water-in-oil emulsion, and then an amount of acid proportional to the amino group in the cationic oil-soluble polymer is added and stabilized. Alternatively, an acid in an amount proportional to the amino group in the cationic oil-soluble polymer may be added to the water-in-oil dispersion in advance, and the cationic oil-soluble polymer may be added after polymerization. Preferably, an acid is added in advance, and a cationic oil-soluble polymer is added after polymerization.

The acid added as described above is to neutralize and dissociate the amino group of the cationic oil-soluble polymer to enhance the dispersibility of the cationic oil-soluble polymer and improve the function as a dispersion stabilizer. Another purpose is to prevent degradation of the water-soluble polymer by adjusting the water-in-oil dispersion pH after polymerization. As the acid used for such a purpose, any acid may be used as long as it does not adversely affect the water-soluble polymer in the aqueous phase and the dispersion form retention. Specific examples include succinic acid, acetic acid, citric acid, adipic acid and the like.

The amount of acid to be added is 30 mol% or more based on the amino group in the molecule of the cationic oil-soluble polymer in the water-in-oil monomer dispersion before polymerization or the water-in-oil polymer dispersion after polymerization. Added. Further, it is preferably 30 mol% or more and 1000 mol% or less, more preferably 50 mol% or more and 500 mol% or less.

The acid can be replaced by a monomer having an anionic group. That is, when an amphoteric water-soluble polymer is produced, it is used as a raw material without neutralizing a monomer containing a carboxyl group or a sulfone group. When the amount of the acid of the monomer having an anionic group is insufficient, the above succinic acid, acetic acid, citric acid, adipic acid and the like are added as an additional acid. The same operation can be performed when producing an anionic water-soluble polymer.

The water-soluble polymer in the present invention is polymerized using a water-in-oil dispersion polymerization method or a water-in-oil emulsion polymerization method. The water-soluble polymer can be produced by any of cationic, amphoteric, nonionic and anionic. The water-in-oil dispersion polymerization method uses a monomer or a monomer mixture of two or more copolymerizable monomers as water, an oily substance comprising at least water-immiscible hydrocarbons, and water-in-oil. This is a method of synthesizing by mixing an effective amount for forming a mold emulsion and at least one surfactant having HLB, and stirring strongly to form a water-in-oil dispersion, followed by polymerization.

Examples of oily substances composed of hydrocarbons used as a dispersion medium include paraffins, mineral oils such as kerosene, light oil, and middle oil, or hydrocarbon-based synthetic oils having characteristics such as boiling point and viscosity substantially in the same range as these. Or a mixture thereof. As content, it is the range of 20 weight%-50 weight% with respect to the total amount of water-in-oil dispersion liquid, Preferably it is the range of 20 weight%-35 weight%.

Examples of at least one surfactant having an amount effective to form a water-in-oil dispersion and HLB are HLB 3-13 nonionic surfactants, specific examples of which include sorbitan monooles. -Sorbitan monostearate, sorbitan monopalmitate and the like. The addition amount of these surfactants is 0.5 to 10% by weight, preferably 1 to 5% by weight, based on the total amount of the water-in-oil emulsion.

After the polymerization, a hydrophilic interfacial modifier called a phase inversion agent is added to make the dispersed particles covered with the oil film easy to adjust to water, and the water-soluble polymer inside is easily dissolved as necessary. Dilute with water and use for each application. Examples of hydrophilic interfacial chemicals are cationic interfacial chemicals and HLB 9-15 nonionic interfacial chemicals, such as polyoxyethylene polyoxypropylene alkyl ether systems and polyoxyethylene alcohol ether systems. is there.

The water-soluble polymer in the present invention can be produced by any of cationic, amphoteric, nonionic and anionic, and can be produced by a water-in-oil dispersion polymerization method. The cationic water-soluble polymer can be produced by polymerization using a cationic monomer or a cationic monomer and a nonionic monomer. The amphoteric water-soluble polymer can be produced by polymerization using a cationic monomer, an anionic monomer and a nonionic monomer. The anionic water-soluble polymer can be produced by polymerization using an anionic monomer or an anionic monomer and a nonionic monomer.

Examples of the cationic monomer include dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylamide, and examples of the quaternary ammonium group-containing polymer include the tertiary amino-containing monomer. (Meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, ) Acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloyloxy 2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride, etc. .

Examples of the anionic monomer include methacrylic acid, acrylic acid, itaconic acid, maleic acid, vinyl sulfonic acid, vinyl benzene sulfonic acid, 2-acrylamido 2-methylpropane sulfonic acid, and salts thereof. These may be used alone or in combination of two or more.

Examples of the water-soluble nonionic monomer used include (meth) acrylamide, N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, and N-vinylpyrrolidone. N-vinylformamide, N-vinylacetamide, acryloylmorpholine, acryloylpiperazine and the like.

For the water-soluble polymer of the present invention, methylene bisacrylamide or ethylene glycol di (meth) acrylate as a polyfunctional monomer having a plurality of vinyl groups, N, N- Dimethylacrylamide or the like can be applied.

The polymerization conditions are usually appropriately determined depending on the monomer used and the copolymerization mol%, and the temperature is 20 to 80 ° C., preferably 20 to 60 ° C. For the initiation of polymerization, a radical polymerization initiator is used. These initiators may be either oil-soluble or water-soluble, and can be polymerized by any of azo, peroxide, and redox systems. Examples of oil-soluble azo initiators include 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2-methylpropionate), 4,4-azobis (4-methoxy-2,4dimethyl) valeronitrile and the like.

Examples of water-soluble azo initiators include 2,2′-azobis (amidinopropane) dichloride, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] And dihydrochloride, 4,4′-azobis (4-cyanovaleric acid), and the like. Examples of redox systems include a combination of ammonium peroxodisulfate and sodium sulfite, sodium hydrogen sulfite, trimethylamine, tetramethylethylenediamine, and the like. Further examples of peroxides include ammonium or potassium peroxodisulfate, hydrogen peroxide, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, succinic peroxide, t-butylperoxy 2-ethylhexanoate, and the like. I can give you.

Since the dispersion is stabilized by the cationic oil-soluble polymer of the present invention, it is possible to obtain a high concentration product having high stability. The reason why a water-in-oil dispersion that is stable and excellent in dissolution according to the present invention is obtained is that when a cationic oil-soluble polymer is brought into contact with an aqueous phase that has been pH-adjusted with an acid. Furthermore, it is considered that the contact portion forms a salt and becomes water-dispersible (water-soluble) and strongly adsorbs to the aqueous phase.

(Examples) The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.
(Synthesis Example 1)

In a reaction vessel equipped with a stirrer and a temperature controller, 24.75 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C., 5.48 g (30 mol%) of dimethylaminoethyl methacrylate (hereinafter abbreviated as DMM), lauryl acrylate (carbon number 12) , Hereinafter abbreviated as LA) 19.52 g (70 mol%), 3-mercapto 1,2-propanediol 0.25 g, dimethyl-2,2-azobisisobutyrate (V-601, manufactured by Wako Pure Chemical Industries) 5 g (2% by weight of monomer) was charged and dissolved. The temperature of the monomer solution was kept at 70 to 73 ° C., and nitrogen substitution was performed for 30 minutes to initiate the polymerization reaction. The reaction was completed at a reaction temperature of 71 ± 2 ° C. for 5 hours to complete the reaction.
(Synthesis Example 2)

Polymerization was carried out in the same manner as in Example 1, except that 3.52 g (20 mol%) of DMM and 21.48 g (80 mol%) of LA were used as monomers.
(Synthesis Example 3)

Polymerization was carried out in the same manner as in Example 1, except that 12.39 g (60 mol%) of DMM and 12.61 g (40 mol%) of LA were used as monomers.
(Synthesis Example 4)

Polymerization was carried out in the same manner as in Example 1, except that 6.40 g (30 mol%) of DMM and 18.60 g (70 mol%) of 2-ethylhexyl acrylate were used as monomers.
(Synthesis Example 5)

Polymerization was carried out in the same manner as in Example 1, except that 0.50 g (3 mol%) of DMM and 24.50 g (97 mol%) of LA were used as monomers.
(Synthesis Example 6)

Polymerization was carried out in the same manner as in Example 1 except that 14.95 g (30 mol%) of DMM and 10.5 g (70 mol%) of ethyl acrylate (carbon number 2) were used as monomers.
(Synthesis Example 7)

Polymerization was carried out in the same manner as in Example 1 except that 3.76 g (30 mol%) of DMM and 21.24 g (70 mol%) of behenyl acrylate (22 carbon atoms) were used as monomers.

In Synthesis Examples 1, 2, 3, 4, 5, and 7, a polymer that was uniformly dissolved in isoparaffin was obtained. In Synthesis Example 6, a polymer was precipitated and a uniform polymer was not obtained, and could not be used as a stabilizer.

In a reaction vessel equipped with a stirrer and a temperature controller, 15.0 g of polyoxyethylene (20) sorbitan trioleate was charged and dissolved in 135 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C. Separately, 236 g of 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 92.4 g of 50% aqueous solution of acrylamide (abbreviated as AAM), 1.76 g of 0.2% aqueous solution of methylenebisacrylamide, 0.71 g of isopropyl alcohol ( 0.3 wt% of monomer) and 5.00 g of succinic acid and 4.14 g of ion-exchanged water were each collected, mixed and completely dissolved. Thereafter, the oil and the aqueous solution were mixed, and stirred and emulsified with a homogenizer at 1000 rpm for 15 minutes. The monomer composition at this time is DMQ / AAM = 60/40 (mol%). The obtained emulsion was maintained at a temperature of the monomer solution at 40 to 43 ° C. and purged with nitrogen for 30 minutes, and then dimethyl-2,2-azobisisobutyrate (V-601, manufactured by Wako Pure Chemical Industries). 12 g (0.05% by weight of monomer) was added to initiate the polymerization reaction. The reaction was completed at a reaction temperature of 42 ± 2 ° C. for 12 hours to complete the reaction. The water-in-oil emulsion viscosity after polymerization was 355 mPa · s, and the weight average molecular weight determined by the dynamic light scattering method was 7.2 million.

1% of the oil-soluble polymer of Synthesis Examples 1, 2, 3, 4, 5, 7 was added to the water-in-oil emulsion polymer of Example 3 (in terms of the pure amount of the oil-soluble polymer relative to the total amount of the liquid). Samples were designated as Sample-1, Sample-2, Sample-3, Sample-4, Sample-5, and Sample-6, respectively, and those without oil-soluble polymer were designated as Sample-7.
The results are shown in Table 1.

ＤＭＱ：アクリロイルオキシエチルトリメチルアンモニウム塩化物
ＡＡＭ：アクリルアミド、分散液粘度：ｍＰａ・ｓ、 (Table 1)

DMQ: acryloyloxyethyltrimethylammonium chloride AAM: acrylamide, dispersion viscosity: mPa · s,

The following operation was performed as a mechanical stability test of the water-in-oil emulsion. 5 g of each sample was taken in a 50 ml beaker and stirred with a 30 mm magnetic stirrer at 800 rpm, and the time until the product solidified was measured. The results are shown in Table 2.

(Table 2)

The following experiment was conducted to test the solubility in water. Each sample was dissolved in ion-exchanged water at a concentration of 0.2%, and the time until the viscosity became constant was measured. The results are shown in Table 3.

(Table 3)

From this test result, it can be said that when the present invention is applied to an aggregating agent, workability can be improved by shortening the dissolution time.

The following test was conducted to see the stationary stability. Centrifugation operation was performed for 30 minutes at 3000 rpm with respect to 40 g of each sample, and the amount of each precipitation residue was measured. The results are shown in Table 4.

(Table 4)

From the results of the above tests, it can be seen that the present invention makes it possible to obtain a water-in-oil dispersion that contains a water-soluble polymer in the aqueous phase and is excellent in stability and dissolution.

Claims (5)

Water-in-oil dispersion containing essentially water-immiscible organic liquid, aqueous phase containing water-soluble polymer, acid and cationic oil-soluble polymer having structural units of the following general formulas (1) and (2) .

General formula (1)
Here, R1 is hydrogen or a methyl group, Q is a phenyl group, an aryl group having 7 to 18 carbon atoms, an alkyl group, COOR3 or CONHR4. Here, R3 and R4 are alkyl groups having 4 to 18 carbon atoms. R2 is hydrogen or an alkyl group having 1 to 3 carbon atoms.

General formula (2)
R5 is hydrogen or a methyl group, R6 and R7 are alkyl or alkoxyl groups having 1 to 3 carbon atoms, and R8 is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, which may be the same or different. A represents oxygen or NH, and B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms. X1 represents an anion. The cationic oil-soluble polymer is a copolymer of 50 to 95 mol% of an alkyl (meth) acrylate having an alkyl group having 4 to 18 carbon atoms and 5 to 50 mol% of a dialkylaminoalkyl (meth) acrylate. The water-in-oil dispersion according to claim 1, wherein 30 mol% or more of the acid is added to the water-in-oil monomer dispersion before polymerization or the water-in-oil polymer dispersion after polymerization with respect to the amino group in the molecule of the cationic oil-soluble polymer. The water-in-oil dispersion according to claim 1 or 2. A water-in-oil dispersion according to any one of claims 1 to 3, wherein a surfactant is allowed to coexist. A method for using a water-in-oil dispersion, wherein the water-in-oil dispersion according to any one of claims 1 to 4 is used as an aggregating agent.