JPH11263815A - Water-soluble copolymer (salt) containing sulfo group and carboxy group - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer-soluble copolymer (salt) comprising a sulfo group and a carboxy group which shows an extremely good dispersibility and dispersion stability in a superfine particle dispersion. SOLUTION: This is a copolymer (salt) obtd. by copolymerizing monomer components comprising a sulfo acid group-contg. monomer and a carboxy group contg.-monomer, with a wt. average mol.wt. of 10,000-500,000 and an allowable concn. of insol. calcium of 200 mg/L or more when 100 mg/L of this copolymer (salt) is added under the condition of a temp. of 90 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group and having excellent dispersibility.

[0002]

2. Description of the Related Art Conventionally, inorganic pigments such as calcium carbonate, clay, titanium oxide, and alumina; hydraulic inorganic materials such as cement and gypsum; fuels such as coal, coke, and pitch;
Aqueous dispersants are generally widely used as dispersants for dispersing dyes and the like in water. Examples of these aqueous dispersants include polyacrylic acid, copolymers thereof, α, β-unsaturated dicarboxylic anhydrides represented by olefins such as ethylene, isobutylene, amylene, hexene, diisobutylene and maleic anhydride. Polycarboxylic acid-based dispersants, such as copolymers with polysaccharides, polycarboxylic acid-based polymers such as polymaleic acid, and salts of condensates of naphthalenesulfonic acid, sulfonic acids such as sodium ligninsulfonate and sodium polystyrenesulfonate System dispersants are known. As described above, the water-soluble polymer is widely used industrially as a fine particle dispersant utilizing its properties, and in recent years, the demand for ultrafine particles has been increasing. However, the dispersing ability of the conventional water-soluble polymer dispersant to ultrafine particles is not yet sufficient.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the conventional technical problems, and has a sulfonic acid group and a carboxylic acid group having extremely excellent dispersibility and dispersion stability in ultrafine particle dispersion. It is intended to provide a water-soluble copolymer (salt).

[0004]

The present invention relates to a copolymer (salt) obtained by copolymerizing a monomer component containing a sulfonic acid group-containing monomer and a carboxylic acid group-containing monomer. When the weight average molecular weight is 10,000 to 500,000 and the copolymer (salt) is added at 100 mg / L under the condition of 90 ° C., the insolubilizing concentration of calcium is 200 mg / L or more, preferably 280 mg / L. Water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group
Is provided. Here, the copolymer (salt) of the present invention has a silica concentration of 210 mg / L (in terms of SiO ₂ ), a magnesium concentration of 49 mg / L (in terms of Mg), a sodium hydrogencarbonate concentration of 420 mg / L (in terms of NaHCO ₃ ), a pH of 9, Under the condition of 70 ° C., this copolymer (salt)
Is preferably 140 nm or less after addition of 100 mg / L, and the average particle size of the precipitate is preferably 1,000 nm or less.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The sulfonic acid group-containing monomer constituting the sulfonic acid group- and carboxylic acid group-containing water-soluble copolymer (salt) of the present invention includes a sulfonic acid group-containing polymerizable double bond. The monomer is not particularly limited as long as
For example, a conjugated diene sulfonic acid represented by the following general formula (I) (for example, 2-methyl-1,3-butadiene-1-
Sulfonic acid) (Wherein, R ^{1 to} R ⁶ are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 20 carbon atoms or —SO ₃ X, wherein X is a hydrogen atom, a metal atom, An ammonium group or an amino group, and at least one of R ^{1 to} R ⁶ is —SO ₃ X), (meth) acrylamide—
2-methylpropanesulfonic acid, an unsaturated (meth) allyl ether monomer represented by the following general formula (II) (for example, 3-allyloxy-2-hydroxypropanesulfonic acid, 3-methallyloxy-2-hydroxypropane) Sulfonic acid),

[0006]

Embedded image

[Wherein R ⁷ is a hydrogen atom or a group having 1 to 1 carbon atoms.
8 are the same or different, and represent 0 or an integer of 1 to 100 (provided that a + b + c + d = 0
-100), the (OC ₂ H ₄ ) unit and the (OC ₃ H ₆ ) unit are bonded in an arbitrary order, Y and Z are sulfonic acid groups or hydroxyl groups, and at least one of Y and Z is Sulfonic acid group], 2-hydroxy-3-acrylamidopropanesulfonic acid, styrenesulfonic acid, methallylsulfonic acid, vinylsulfonic acid, allylsulfonic acid, isoamylenesulfonic acid, or salts thereof. Preferably, 2-methyl-1,3-butadiene-1-sulfonic acid, (meth) acrylamido-2-methylpropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, styrenesulfonic acid, or salts thereof. is there. These monomers containing a sulfonic acid group and having a polymerizable double bond can be used alone or in combination of two or more. The amount of the monomer having a polymerizable double bond containing a sulfonic acid group is 2 to 80 mol%, preferably 5 to 50 mol%, and more preferably 1 to 50 mol% in the monomer component.
0 to 35 mol%, and if it is less than 2 mol%, the resulting copolymer (salt) will not have sufficient surface activity, dispersing ability, fiber treatment ability, etc. In some cases, these performances are not satisfied.

The monomer containing a carboxylic acid as a constituent unit is not particularly limited as long as it contains a carboxylic acid group and has a polymerizable double bond.
Examples include acrylic acid, methacrylic acid, α-haloacrylic acid, maleic acid, itaconic acid, vinyl acetic acid, allyl acetic acid, fumaric acid, phosphinocarboxylic acid, β-carboxylic acid, and salts thereof. Preferably, acrylic acid, methacrylic acid, or salts thereof are good. These monomers containing a carboxylic acid group and having a polymerizable double bond can be used alone or in combination of two or more. The amount of the monomer having a polymerizable double bond containing a carboxylic acid group is 9
It is from 8 to 20 mol%, preferably from 95 to 50 mol%, more preferably from 90 to 65 mol%, and if it is less than 20 mol%, the obtained copolymer (salt) has surface activity, dispersing ability and fiber treatment ability. However, when the content is not sufficient, and when the content exceeds 98 mol%, these properties may not be similarly satisfied.

Further, in the water-soluble copolymer (salt) having a sulfonic acid group and a carboxylic acid group of the present invention, in addition to a monomer containing a sulfonic acid group and a carboxylic acid group as constituent units, it is possible to copolymerize with these. One or two other monomers
It is also possible to copolymerize more than one kind. Examples of the other copolymerizable monomer include unsaturated alcohols such as vinyl alcohol, allyl alcohol, methyl vinyl alcohol, ethyl vinyl alcohol, and vinyl glycolic acid, hydroxymethyl (meth) acrylate, and hydroxyethyl (meth). ) Acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, glycerol mono (meth) acrylate, glycerol di (meth) acrylate, polytetramethylene glycol mono (meth) acrylate,
Hydroxyl-containing (meth) such as polytetramethylene glycol di (meth) acrylate, butanediol (meth) acrylate, and hexanediol (meth) acrylate
Acrylic esters, aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, and p-methylstyrene; (meth) methyl (meth) acrylate, ethyl (meth) acrylate, and octyl (meth) acrylate ) Alkyl acrylates, butadiene,
Aliphatic conjugated dienes such as isoprene, 2-chloro-1,3-butadiene and 1-chloro-1,3-butadiene;
Examples thereof include vinyl cyanide compounds such as (meth) acrylonitrile. When these other monomers are copolymerized, the content is preferably 30 mol% or less in the monomer components.

The method for producing the water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group provided in the present invention is as follows. For example, the reaction temperature of the above monomer in the presence of a known polymerization initiator such as hydrogen peroxide, sodium persulfate and potassium persulfate is usually adjusted to 20 to 200.
° C, preferably at 40 to 150 ° C for 0.1 to 20 hours,
Preferably, the polymerization reaction is carried out for 1 to 15 hours to produce a copolymer (salt). In order to make the calcium insolubilizing concentration (maximum permissible concentration that can be solubilized without gelling) 200 mg / L or more when 100 mg / L of this copolymer (salt) is added at 90 ° C., Can be adjusted. Various methods can be used for the prescription, but as one prescription, the polymerization can be carried out by sequentially adding the monomer components used for the polymerization. Here, the term "sequential polymerization" means to introduce a monomer component into a polymerization system in a predetermined amount per unit time or in a variable amount. Usually, the sequential addition time is 1 hour or more, preferably 4 hours or more, and more preferably 8 hours or more. Copolymer (salt) obtained by successive addition
Of the composition distribution becomes narrower, and the concentration of calcium insolubilized when 100 mg / L of this copolymer (salt) is added at 90 ° C. can be increased.

In the above copolymerization reaction, a polymerization solvent can be used in order to smoothly carry out the reaction. As the polymerization solvent, water or a mixture of water and an organic solvent miscible with water can be used. it can. Specific examples of the organic solvent are not particularly limited as long as they can be mixed with water,
Examples include tetrahydrofuran, 1,4-dioxane, alcohols and the like.

In the present invention, the copolymer (salt) concentration is 100 m
Under the conditions of g / L and 90 ° C., the calcium insolubilizing concentration needs to be 200 mg / L or more, preferably 280 mg / L or more.
If it is less than / L, the composition distribution width is wide, so that the surface activity, dispersing ability, and fiber treating ability are insufficient.

The copolymer (salt) of the present invention has a silica concentration of 210 mg / L (in terms of SiO ₂ ), a magnesium concentration of 49 mg / L (in terms of Mg), a sodium hydrogen carbonate concentration of 420 mg / L (in terms of NaHCO ₃ ), pH 9, 70 ° C
Under the conditions described above, the average particle size of the precipitate formed 140 hours after the addition of 100 mg / L of the copolymer (salt) is preferably 1,000 nm or less, more preferably 800 nm or less, and particularly preferably. It is desirable that the thickness be 500 nm or less. If it exceeds 1,000 nm, the dispersing ability,
Dispersion stability becomes insufficient. The adjustment of the average particle size of the precipitate can be achieved by, for example, the above-described sequential polymerization.

Further, the molecular weight of the water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group provided in the present invention is 10,000 to 500,000, preferably 20,000 to 300,000, more preferably 40,000. ~ 300,000. If it is less than 10,000, stable dispersing ability and fiber treatment ability may not be obtained. On the other hand, if it exceeds 500,000, handling becomes difficult due to gelation and the like.

The cation type of the water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group of the present invention thus obtained is not particularly limited.
In order to make the compound water-soluble, hydrogen, an alkali metal, an alkaline earth metal, ammonium, an amine and the like are preferable. Examples of the alkali metal include sodium and potassium.
Examples of the amine include alkylamines such as methylamine, ethylamine, propylamine, dimethylamine, diethylamine, triethylamine, butylamine dibutylamine and tributylamine; polyamines such as ethylenediamine, diethylenetriamine and triethylenetetramine; morpholine and piperidine; and alkaline earth metals. Examples thereof include calcium and magnesium. Preferably, they are hydrogen, sodium, and potassium. These cation species can be exchanged with other cation species by various ion exchange techniques.

The water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group of the present invention contains a component based on a monomer other than the sulfonic acid group-containing monomer and the carboxylic acid group-containing monomer. The spread of the dispersant molecules,
An effect such as control of the adsorption ability to an organic material and an inorganic material is obtained, and in various kinds of fine particles, the dispersing ability, the dispersion stabilizing ability and the like may be improved. The sulfonic acid group and carboxylic acid group-containing water-soluble copolymer of the present invention (salt)
It is used as a dispersant in the dispersion of various dispersions and is used as a dispersion composition. Such dispersions include solid fuels, cements, dyes and / or pigments, metal oxides, or scales formed in boilers, heat exchangers, condensers, and piping. Further, the water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group of the present invention can be dissolved or emulsified in water and used as a fiber treatment agent as in the conventional case. Furthermore, the water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group of the present invention may be used for carbon black, carbon fiber dispersant, agricultural chemical, fertilizer,
It can be used in fields such as surfactants for feeds, synthetic rubbers, synthetic resins, emulsifiers for emulsions and surfactants for cosmetics.

[0017]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. The percentages and parts in the examples are on a weight basis unless otherwise specified.

The weight-average molecular weight (Mw) in the examples is obtained by converting the result determined by gel permeation chromatography (GPC) using a calibration curve prepared using sodium polystyrene sulfonate as a standard sample. Here, the measurement conditions of GPC are as follows. Column: G3000PWXL [manufactured by Tosoh Corporation] Column: GMPWXL [manufactured by Tosoh Corporation] Column: GMPWXL [manufactured by Tosoh Corporation] The columns are connected in series in the order of 〜, and a sample is introduced from the column side. Detector: Differential refractometer RI-8021 [Tosoh Corporation
Eluent: water / acetonitrile / sodium sulfate = 2,1
00/900/15 (weight ratio) Flow rate; 1.0 ml / min Temperature; 40 ° C. Sample concentration; 0.2% Sample injection volume; 400 μl

Under the condition of 90 ° C., 100 parts of the copolymer (salt) was added.
The conditions for measuring the calcium insolubilization concentration when mg / L was added are as follows. Using a 300 ml Erlenmeyer flask, copolymer (salt) concentration 100 mg / L, calcium concentration (adjusted by calcium chloride dihydrate) 40 mg
/ L, adjust to a total volume of 200 ml. At this time, the pH of the aqueous solution is adjusted to 8.6 with a borate buffer. This was stored in a water bath at 90 ° C. for 1 hour immediately after 380
The absorbance in nm was measured with a spectrophotometer U1100 (manufactured by Hitachi, Ltd.). Calcium concentration 80, 120,
160, 200, 240, 280, 320, 360, 4
The amount was changed to 00 mg / L, and the absorbance was measured in the same manner as described above. The calcium concentration minimum value at which the absorbance exceeded 0.01 was defined as the insolubilized calcium concentration.

Under the conditions of a silica concentration of 210 mg / L (in terms of SiO ₂ ), a magnesium concentration of 49 mg / L (in terms of Mg), a sodium hydrogencarbonate concentration of 420 mg / L (in terms of NaHCO ₃ ), pH 9, and 70 ° C., the copolymer ( Salt)
Conditions for measuring the average particle size of the precipitate formed 140 hours after the addition of 00 mg / L are as follows. That is, using a 500 ml beaker, a silica concentration of 210
mg / L (in terms of SiO ₂ , adjusted by sodium metasilicate 9-hydrate), magnesium concentration 49 mg / L (M
g conversion, adjusted by magnesium sulfate heptahydrate), sodium hydrogen carbonate concentration 420 mg / L (converted to NaHCO ₃ , adjusted by sodium hydrogen carbonate), copolymer (salt)
The concentration is adjusted to 100 mg / L, pH 9 (adjusted with sulfuric acid and sodium hydroxide), and the total amount is adjusted to 500 ml.
This solution was sealed in a 250 ml polyethylene container capable of sealing so that no air was mixed in, and sealed at 70 ° C. and 140 ° C.
The average particle size of the precipitate after standing for a period of time is measured using a laser particle size analysis system; LPA-3000 / 3100 [Otsuka Electronics Co., Ltd.
Manufactured).

REFERENCE EXAMPLE 1 593 g of a 40% aqueous solution of sodium 2-methyl-1,3-butadiene-1-sulfonate, 462 g of an 80% aqueous solution of acrylic acid, 95 g of 2-hydroxyethyl methacrylate, and 35 g of water in 90 g of water. A solution of 10 g of an aqueous solution of 10% hydrogen peroxide was uniformly dropped over a period of 10 hours while stirring under reflux in a 2 L internal vessel charged with 450 g of water. After the completion of the dropwise addition, the copolymer (salt) is kept under reflux for 2 hours.
I got

Reference Example 2 593 g of a 40% aqueous solution of sodium 2-methyl-1,3-butadiene-1-sulfonate, 462 g of an 80% aqueous solution of acrylic acid, 95 g of 2-hydroxyethyl methacrylate, and 35 g of water in 85 g of water. A solution prepared by dissolving 15 g of an aqueous solution of 15% hydrogen peroxide was added dropwise to a container having an internal volume of 2 L charged with 450 g of water over 10 hours while stirring under reflux. After completion of the dropwise addition, the mixture was kept under reflux for 2 hours to obtain a copolymer (salt).

Reference Example 3 In a container having an inner volume of 2 L, 1,063 g of water, 167 g of acrylamido-2-methylpropanesulfonic acid, 323 g of an 80% strength aqueous solution of acrylic acid, 67 g of 2-hydroxyethyl methacrylate, 35% peroxide 30 g of hydrogen water was charged and polymerization was performed under reflux for 4 hours to obtain a copolymer (salt).

Reference Example 4 740 g of water and a 40% strength aqueous solution of 3-allyloxy-2-hydroxypropanesulfonic acid 5 were placed in a container having an inner volume of 2 L.
98 g, 333 g of 80% strength aqueous acrylic acid solution, 35
% Hydrogen peroxide solution was charged, and polymerization was carried out under reflux for 4 hours to obtain a copolymer (salt).

Polymer A 403 g of an aqueous solution of acrylamide-2-methylpropanesulfonic acid having a concentration of 40%, 462 g of an aqueous solution of acrylic acid having a concentration of 80%, and 100 g of a 35% hydrogen peroxide solution were mixed with 810 g of water.
Was separately added dropwise over 10 hours under reflux to a container having an inner volume of 2 L. After completion of the dropwise addition, the mixture was kept under reflux for 2 hours to obtain a copolymer (salt). Polymer B polyacrylic acid

The weight average molecular weights (Mw) of the polymers A and B used in the above Reference Examples 1 to 4 and Comparative Examples, and the content of calcium when adding 100 mg / L of the copolymer (salt) at 90 ° C. Table 1 shows the insolubilization concentration.

[0027]

[Table 1]

Examples 1-4 and Comparative Examples 1-3 10 g of iron tetroxide [a reagent manufactured by Wako Pure Chemical Industries, Ltd.] was added to 100 g of water to which a dispersant described in Table 2 was added, and shaken for 10 minutes. By measuring the sedimentation volume after standing for 24 hours, the dispersibility and the particle size of the silica precipitate were evaluated. Table 2 shows the results. As is clear from Table 2, the water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group of the present invention.
It can be seen that is excellent in dispersibility.

[0029]

[Table 2]

Examples 5-8, Comparative Examples 4-5 10 g of titanium dioxide (TITONER-21, rutile type, primary particle diameter 180 nm) was added to 100 g of water to which a dispersant described in Table 3 was added. The dispersibility was evaluated by measuring the average particle size after stirring for 5 minutes. In addition, the particle size is a laser particle size analysis system; LP
A-3000 / 3100 [manufactured by Otsuka Electronics Co., Ltd.]. Table 3 shows the results. As is clear from Table 3, the water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group of the present invention has excellent dispersibility.

[0031]

[Table 3]

[0032]

The water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group of the present invention can be used for organic materials, inorganic materials,
Excellent dispersibility can be imparted to inorganic pigments, metal oxides and the like.

Continuation of the front page (72) Inventor Katsuhiro Ishikawa 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Corporation

Claims (2)

[Claims] 1. A copolymer (salt) obtained by copolymerizing a monomer component containing a sulfonic acid group-containing monomer and a carboxylic acid group-containing monomer, and having a weight average molecular weight of 10,000 to 50
Under the conditions of 10,000 and 90 ° C., this copolymer (salt) is
A water-soluble copolymer (salt) containing a sulfonic acid group and a carboxylic acid group, wherein the allowable concentration of calcium insolubilized when added at 00 mg / L is 200 mg / L or more. 2. Under the conditions of a silica concentration of 210 mg / L (in terms of SiO ₂ ), a magnesium concentration of 49 mg / L (in terms of Mg), a sodium hydrogencarbonate concentration of 420 mg / L (in terms of NaHCO ₃ ), pH 9, and 70 ° C. Polymer (salt)
The sulfonic acid group- and carboxylic acid group-containing water-soluble copolymer (salt) according to claim 1, wherein the average particle size of the precipitate formed after 140 hours when 100 mg / L is added is 1,000 nm or less.