JP5391824B2 - Aqueous thickener, method for producing the same, and aqueous thickener using the same - Google Patents

Description

The present invention relates to the thickening of a solution having strong acidity, a solution having a high salt concentration, and an alcoholic solution, among the commonly used thickening agents.
More specifically, a water-based thickener comprising a specific sulfonic acid (salt) group-containing water-soluble copolymer, safe and having a high thickening effect with a small amount of addition, and a method for producing the thickener, In addition, the present invention relates to an aqueous thickener used for pharmaceuticals and cosmetics containing the thickener.

Water-soluble thickeners that can be used in a wide range of fields such as pharmaceuticals and cosmetics include various polysaccharides, natural polymers such as gelatin, synthetic polymers such as polyoxyethylene and crosslinked poly (meth) acrylic acid, montmorillonite, Inorganic minerals such as silica are known.
Among these, cross-linked poly (meth) acrylic acid is particularly inexpensive and has a high thickening effect and gels in a small amount. Therefore, it is used as a water-soluble thickener or stabilizer in the pharmaceutical and cosmetic industries, particularly cosmetics. It is used a lot.
However, cross-linked poly (meth) acrylic acid does not increase in viscosity because the dissociation of carboxyl groups is suppressed under acidic conditions of pH 5 or lower or in an aqueous solution containing salts, and the viscosity is extremely lowered. For this reason, it cannot be used in a formulation that requires acidic conditions and a salt coexistence system. In particular, as a thickener for cosmetics where usability occupies an important point, this characteristic may be a fatal defect.
For example, under acidic conditions of pH 5 or lower or in the presence of salts, it is necessary to greatly increase the blending amount in order to maintain the thickening effect, and as a result, the usability is significantly impaired. When such a substance is applied to the skin, a sticky feeling is produced, and this sticky feeling becomes a very serious problem in terms of the usability of the cosmetic. Some cosmetic formulations have a high ethanol concentration, but at present, it is an extremely difficult task to efficiently thicken such formulations with a conventional thickener such as carboxyvinyl polymer.

In order to solve this problem, a copolymer of acrylamide alkyl sulfonic acid and (meth) acrylic acid (JP-A-9-157130), a copolymer of acrylamide alkyl sulfonic acid and an alkyl group-containing unsaturated monomer Copolymer (JP-A-10-279636) or a copolymer of 2-acrylamido-2-methylpropane sulfonate and a cross-linkable monomer such as methylenebisacrylamide (JP-A 2001-114641, International Publication pamphlets WO2008 / 107034) and the like have been studied for cosmetics.
However, even with these copolymers, the molecular weight does not increase, a branched structure is formed in the polymer, an insoluble matter is generated, and further, in the acidic region or in the presence of ethanol. Insufficient thickening at the time, and poor handleability.

JP-A-9-157130 JP-A-10-279636 JP 2001-114641 A International Publication No. 2008/107034 Pamphlet

  The present inventors have conducted various studies to obtain an aqueous thickener that exhibits high thickening in the acidic region, particularly in the presence of ethanol, has a high spinnability, and is safe for the human body.

  As a result of diligent investigation focusing on the impurities normally contained in the sulfonic acid (salt) group-containing monomer, the present inventor has copolymerized a sulfonic acid (salt) group-containing monomer that does not contain a specific component or more. It was found that the aqueous dispersant obtained in this way exhibits high viscosity in the acidic region and in the presence of alcohol, has high spinnability, and is easy to handle because it does not generate insoluble matter, thereby completing the present invention. It was.

That is, the present invention is as follows.
[1] The monomer (A) shown below is 15 to 80% by weight, the monomer (B) and / or the monomer (C) is 20 to 85% by weight, and a crosslinkable monomer. A water-based copolymer obtained by radical copolymerization under conditions containing no water, and having a GPC top peak molecular weight of 2 million to 30 million based on polyacrylic acid as a reference substance.
Monomer (A); 2-acrylamido-2-methylpropanesulfonic acid and / or a salt thereof, wherein the content of 2-methyl-2-propenyl-1-sulfonic acid is 120 ppm by weight or less.
Monomer (B); (meth) acrylic acid and / or a salt thereof.
Monomer (C): monofunctional acrylamide or acrylate ester in which an alkyl group may be bonded to the N atom.
[2] The aqueous thickener according to [1], wherein the monomer (A) is produced through the following first to fourth steps.
1st process; The process of manufacturing the liquid mixture of acrylonitrile and fuming sulfuric acid.
Second step: A mixture of isobutylene and the mixed liquid produced in the first step are mixed and contacted, and 2-methyl-2-propenyl-1-sulfonic acid is 12000 ppm by weight or less of 2-acrylamido-2-methylpropanesulfonic acid. A step of obtaining an acrylonitrile slurry liquid.
Third step: A step of solid-liquid separation of the slurry liquid obtained in the second step to obtain a crude cake of 2-acrylamido-2-methylpropanesulfonic acid, and then washing the crude cake with acrylonitrile.
Fourth step: A step of drying the washed coarse cake obtained in the third step.
[3] The aqueous thickener according to [1] or [2], wherein the monomer (C) is a monomer selected from acrylamide, N-alkylacrylamide, and N, N-dialkylacrylamide.
[4] The aqueous thickening according to any one of [1] to [3], wherein the content of 2-methyl-2-propenyl-1-sulfonic acid in the monomer (A) is 60 ppm by weight or less. Agent.
[5] The aqueous thickening according to any one of [1] to [4], wherein the content of 2-methyl-2-propenyl-1-sulfonic acid in the monomer (A) is 30 ppm by weight or less. Agent.
[6] The method for producing an aqueous thickener according to any one of [1] to [5], wherein the monomers (A), (B) and / or (C) are gel-polymerized.
[7] An aqueous thickener containing the aqueous thickener according to any one of [1] to [5] and any one of mineral acid, organic acid, or alcohol as essential components.

  The aqueous thickener of the present invention exhibits high thickening in the acidic region, particularly in the presence of alcohol, has a high spinnability, and is easy to handle because there is no gel or the like, and there is no change in the thickening effect over time. Therefore, it is possible to adjust an aqueous thickener having performance with excellent quality.

  The aqueous thickener of the present invention has a molecular weight at the top peak of GPC (based on polyacrylic acid as a reference substance) obtained by radical copolymerization of the monomers (A) to (C) described below. (Hereinafter abbreviated as top peak molecular weight) is a water-soluble copolymer having 2 million to 30 million. If necessary, other monomers (excluding the crosslinkable monomer) can be copolymerized to 20% by weight or less of the total monomers.

さらに、本発明者らは、ＩＢＳＡを一定量以下に制御したＡＴＢＳを使用することにより、驚くべきことに、得られた共重合体が、曳糸性が大きく、強酸性やアルコール下での長期安定性に優れた水系増粘剤となることを見出した。
その理由は、定かではないが、ＩＢＳＡは不飽和結合を含んでいるため、共重合体の成分として取り込まれるが、ＡＴＢＳよりスルホン酸基の長さが短く且つアミド基を含まないため、それが性能低下に繋がったとも考えられる。また、退化的連鎖移動によってポリマー末端に結合するＩＢＳＡ単位はポリマーの熱安定性を低下させると推定されるが、この不安定末端が減少することによって長期安定性が向上した可能性も強い。
なお、曳糸性が大きいと、化粧料として使用した場合の、肌への載りや伸びが良くなるので好ましい。 ○ Monomer (A)
The sulfonic acid (salt) group-containing monomer of the present invention is 2-acrylamido-2-methylpropanesulfonic acid (hereinafter abbreviated as ATBS) and / or a salt thereof.
The monomer is usually produced using acrylonitrile, sulfuric acid or isobutylene. These three components react stoichiometrically in equimolar amounts, but acrylonitrile is used in a large excess because it also serves as a reaction medium. Since ATBS is sparingly soluble in acrylonitrile, the product is in the form of a slurry. First, a crude ATBS is separated from the slurry and purified in the next purification step. The ATBS thus produced contains impurities, and there is a problem that the molecular weight of the polymer varies depending on the content of the substance.
The inventors of the present invention have confirmed that the impurity is 2-methyl-2-propenyl-1-sulfonic acid (hereinafter abbreviated as IBSA) represented by the following formula (1).

Furthermore, the present inventors surprisingly use the ATBS in which the IBSA is controlled to a certain amount or less, and surprisingly, the obtained copolymer has a high spinnability and a long period under strong acidity or alcohol. It has been found that it is an aqueous thickener with excellent stability.
The reason is not clear, but since IBSA contains an unsaturated bond, it is incorporated as a component of the copolymer, but since the sulfonic acid group is shorter than ATBS and does not contain an amide group, It is thought that it led to performance degradation. Moreover, although it is estimated that the IBSA unit couple | bonded with a polymer terminal by degenerative chain transfer reduces the thermal stability of a polymer, possibility that long-term stability improved by reducing this unstable terminal is also strong.
In addition, it is preferable that the spinnability is large, because when it is used as a cosmetic, it can be put on and stretched on the skin.

  In the present invention, the content of IBSA in ATBS needs to be 120 ppm by weight or less, preferably 60 ppm by weight or less, and more preferably 30 ppm by weight or less. If the IBSA content in ATBS exceeds 120 ppm by weight, the spinnability and thickening of the produced water-based thickener will decrease, and the long-term stability will also decrease. In particular, the performance is improved at 30 ppm by weight or less.

In general, since commercially available ATBS contains 200 ppm by weight or more of IBSA, ATBS used in the present invention can be produced by removing IBSA from such ATBS.
For such purification, recrystallization using an organic solvent azeotroped with methanol, acetic acid, or water is conceivable. However, such a method is not suitable for industrial mass production and has a large amount of waste solvent, which increases costs.
Therefore, a method of controlling the IBSA concentration to 120 ppm by weight or less in the ATBS manufacturing process is preferable.

That is, the ATBS of the present invention is continuously produced in four steps using acrylonitrile, isobutylene and fuming sulfuric acid as raw materials.
The first step is a step of producing a mixed liquid of acrylonitrile and fuming sulfuric acid. The purpose of this step is to uniformly mix acrylonitrile and sulfuric acid, but since acrylonitrile contains a small amount of water, it includes capturing this water with fuming sulfuric acid. In order to suppress polymerization of acrylonitrile and coloration of the mixed solution, it is preferable to maintain the mixed solution temperature from 0 ° C. to −15 ° C. and set the liquid residence time in the mixing tank to 10 minutes or more. More preferably, the residence time is 90 minutes or more. When a large amount of sulfur trioxide component remains in the fuming sulfuric acid, sulfur trioxide chemically reacts with isobutylene in the next step to generate IBSA.
The second step is a step in which the mixed liquid produced in the first step and isobutylene are mixed and contacted to obtain an ATBS acrylonitrile slurry liquid. In this process, acrylonitrile, sulfuric acid (or fuming sulfuric acid), and isobutylene should react in equimolar amounts to produce the same mole of ATBS. However, since acrylonitrile is also used as a solvent, acrylonitrile of ATBS is used in this process. It becomes a slurry liquid.
The temperature in this step is preferably 40 to 70 ° C., and the residence time in the tank is preferably 90 to 180 minutes. In this step, fuming sulfuric acid and isobutylene are side-reacted to produce IBSA.
Examples of a method for reducing the amount of IBSA produced include a method for reducing the sulfur trioxide content brought from fuming sulfuric acid. The compound is converted into another compound by further reaction with sulfur trioxide in a sequential reaction, the case where it is converted into an alcohol compound by reacting with moisture, or the reaction is converted into another acrylamide compound by reacting with acrylonitrile. There are cases, and there is a method of using these to eliminate the compound once produced. In this step, in order to obtain ATBS used in the present invention, it is necessary to suppress IBSA in the product of this step to 12000 ppm by weight or less.
The third step is a step of solid-liquid separation of the slurry liquid obtained in the second step to obtain a crude cake of ATBS, and then washing the coarse cake with acrylonitrile. The latter half of this step is for the purpose of removing impurities from the ATBS coarse cake, and includes the operation of washing away IBSA adhering to the crystal surface.
The fourth step is a step of drying the washed coarse cake obtained in the third step. The main purpose of this step is to remove the remaining acrylonitrile, but it also includes the purpose of reducing IBSA by utilizing the property of thermal decomposition of IBSA. The IBSA contained in the powder obtained after drying is 120 ppm by weight or less.
By changing the process conditions based on the content of IBSA in the first step, the second step, the third step, and the fourth step, the content of the compound can be maintained at a low concentration.

  The weight ratio in the copolymer of the monomer (A) used by this invention is 15 to 80 weight%, and 20 to 60 weight% is preferable. When the weight ratio of the monomer (A) is less than this value, the thickening under the acidic region is lowered or the spinnability is not increased. If this value is exceeded, the water-based thickener will increase the water solubility, but the skin irritation of the cosmetic will increase.

○ Monomer (B)
The monomer (B) that can be used in the present invention is (meth) acrylic acid and / or a salt thereof. In the present invention, (meth) acrylic acid means acrylic acid or methacrylic acid. Preferably acrylic acid and / or its salt is used.

○ Monomer (C)
The monomer (C) that can be used in the present invention is a monofunctional acrylamide or acrylate ester in which an alkyl group may be bonded to the N atom.
Monofunctional acrylamides in which an alkyl group may be bonded to the N atom include acrylamide, N-ethylacrylamide, N-propylacrylamide, N-isopropylacrylamide, N-tert-butylacrylamide, N, N-dimethylacrylamide, N , N-diethylacrylamide, N, N-dimethylaminoethylacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminoethylacrylamide methyl chloride, N, N-dimethylaminopropylacrylamide methyl chloride, etc. The Acrylamide, N-ethylacrylamide, N-propylacrylamide, N-isopropylacrylamide, and N, N-diethylacrylamide, which are easy to handle and easily available, are preferred.
Examples of the acrylate ester to which an alkyl group may be bonded to the N atom include N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl acrylate, N, N-dimethylammonium ethyl acrylate methyl chloride, N, N- Examples thereof include dimethylaminopropyl acrylate. N, N-dimethylaminoethyl acrylate and N, N-dimethylammonium ethyl acrylate methyl chloride, which are easily available, are preferred.
Most preferred as the monomer (C) of the present invention are acrylamide, N-ethylacrylamide, N-isopropylacrylamide, and N, N-diethylacrylamide.

  The weight ratio in the copolymer of the monomer (B) and / or monomer (C) used in the present invention is 20 to 85 in total of the monomer (B) and the monomer (C). % By weight, preferably 40 to 80% by weight. If the weight ratio of the monomer (B) and / or the monomer (C) is less than this value, the water solubility decreases, and if it exceeds this value, the stability decreases.

  When the monomer (A) or monomer (C) used in the present invention is a salt, the salt includes lithium, sodium, potassium, calcium, barium, iron, cobalt, nickel, copper, zinc, aluminum. And metal ammonium salts such as ammonia, trialkylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine and the like, and one kind or a plurality of them can be used in combination.

○ Other monomers The copolymer of the present invention is not limited to the monomers (A), (B) and (C) described above, and is within the range of 20% by weight or less of the total monomers. Monomers can be used. Examples of other monomers include (anhydrous) unsaturated carboxylic acids (anhydrides) such as maleic acid, fumaric acid, itaconic acid or salts thereof, methyl (meth) acrylate, ethyl (meth) acrylate, ( (Meth) acrylic acid (meth) acrylic acid, (meth) acrylic acid alkyl esters such as 2-ethylhexyl (meth) acrylic acid, and (meth) acrylic methyl ethers of dihydric alcohols such as ethylene glycol, polyethylene glycol, propyne glycol, and butanediol Acid monoesters, carboxylic acid vinyl esters such as glycidyl (meth) acrylate, vinyl acetate, propyl acetate, (meth) acrylamide alkylalkane sulfonic acids other than ATBS, vinyl sulfonic acids, allyl sulfonic acids, styrene sulfonic acids, 2- Unsaturated compounds such as hydroxy-3-allyloxypropane sulfonic acid Examples thereof include phonic acid or salts thereof, (meth) acrylonitrile, styrene monomers such as styrene, α-methyl styrene, p-methyl styrene, chloromethyl styrene, vinyl pyridine, vinyl imidazole, and allylamine. It may be used or may be used in combination.
The amount of these monomers used is preferably within 15% by weight, and more preferably within 10% by weight.
However, in this invention, a crosslinkable monomer must not be included. Examples of such crosslinkable monomers include water-soluble monomers such as N, N-methylenebisacrylamide, triallylamine, and triethylene glycol dimethacrylate, and oil-soluble monomers such as trimethylolpropane triacrylate. .
Since such a crosslinkable monomer crosslinks the copolymer to form an insoluble part (crosslinked body), use should be avoided even for the purpose of increasing the molecular weight.

-Top peak molecular weight of copolymer The top peak molecular weight of the copolymer of this invention is 2 million-30 million, and a preferable top peak molecular weight is 4 million-20 million. If the top peak molecular weight is less than this range, the thickening effect is insufficient, and if it exceeds this range, the solubility decreases. The molecular weight of the copolymer is, as described above, the molecular weight at the maximum point of the peak curve obtained by aqueous gel permeation chromatography (hereinafter abbreviated as GPC) using polyacrylic acid as a reference substance.

-Manufacturing method of aqueous thickener The copolymer of this invention is used for an aqueous thickener.
There are many known methods for producing an aqueous thickener, such as gel polymerization, aqueous solution polymerization and reverse phase suspension polymerization, which are used in ordinary polymer synthesis methods. For the synthesis of the copolymer, a gel polymerization method is preferred because the polymer can be easily made to have a high molecular weight and the polymerization operation and the molecular weight can be easily adjusted. The polymerization operation may be batch or continuous. Specific examples of the continuous gel polymerization method include a continuous belt polymerization method in which an aqueous monomer solution is continuously polymerized on a movable belt.

As the polymerization initiator, a redox polymerization initiator is preferable. Instead of the redox polymerization initiator, a monomer aqueous solution containing a photopolymerization initiator may be irradiated with active energy rays such as ultraviolet rays to be radically polymerized. .
Specific examples of the polymerization initiator include alkali metal persulfates such as sodium persulfate and potassium persulfate, persulfates such as ammonium persulfate, hydrogen peroxide, cumene hydroperoxide, benzoyl peroxide, and t-butyl peroxide. , Organic peroxides such as benzoyl peroxide, 2,2′-azobis (4-cyanovaleric acid), 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide], 2 Azo compounds such as 2,2'-azobisisobutyronitrile. At this time, it is preferable to use together a reducing agent for redox formation such as transition metal salt, bisulfite, L-ascorbic acid (salt), erythorbic acid (salt), amine compound and the like.
The amount of the polymerization initiator to be added is adjusted according to the type of polymerization initiator used, the composition of the target polymer, the degree of polymerization, the viscosity, etc., but is based on the total amount of all monomers. 5 to 10,000 ppm by weight is used. Preferably it is 10 to 5000 ppm by weight, and more preferably 15 to 3000 ppm by weight.
In the present invention, as a result of reducing the content of IBSA that also functions as a chain transfer agent, the amount of polymerization initiator used can be reduced.

The gel polymerization method used in the production of the aqueous thickener of the present invention is a polymerization method employed in a polymer production method such as for organic flocculants in order to obtain an extremely high molecular weight water-soluble polymer. According to this, the resulting polymer is obtained as a gel.
The technical characteristics of the gel polymerization method are that the aqueous solution concentration of the monomer is about 20 to 50% by weight, and the amount of the polymerization initiator used is very small, that is, 1000 ppm by weight or less. Under such conditions, when the polymerization is started at an initial reaction liquid temperature of 5 to 10 ° C., the reaction liquid is converted into a highly viscous gel, and stirring and removal of reaction heat can no longer be performed in the middle of the reaction. By leaving it for a certain period of time, the polymerization is usually completed after the maximum temperature of 80 to 100 ° C., and the desired high molecular weight water-soluble polymer is obtained.
In the polymerization reaction by the gel polymerization method, a preferable polymerization start temperature is 0 to 30 ° C, more preferably 5 to 20 ° C, and a preferable polymerization arrival temperature is 70 to 105 ° C, more preferably 80 to 100 ° C. What is necessary is just to adjust a monomer density | concentration so that it may enter into the range of this superposition | polymerization start temperature and superposition | polymerization attainment temperature. The preferred polymerization time is about 30 minutes to 6 hours.

Aqueous thickening liquid The aqueous thickening liquid of the present invention is mainly used as an acidic water-soluble liquid, for medical use and cosmetics, in an acidic region or in the presence of alcohol under a high salt concentration.
The acidic aqueous solution is an acidic cleaning agent containing hydrochloric acid, citric acid, or the like as a cleaning component, as a cleaning agent for removing dirt such as tiles in the bathroom, washstands, toilet bowls in bathrooms, indoor tiles, and the like.
Mineral acids or organic acids contained in the liquid acidic detergent of the present invention include mineral acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid, and organic acids such as acetic acid, citric acid, malic acid, sulfamic acid and glycolic acid. Can be mentioned. Moreover, these acids can be used individually or in combination of 2 or more types.
The amount of acid contained in the liquid acidic cleaning agent cannot be generally stated because the cleaning power and safety differ depending on the type of acid, but is preferably in the range of 3 to 30% by weight, and in the range of 5 to 20% by weight. More preferred. If it is less than 3% by weight, the detergency is insufficient, and if it exceeds 30% by weight, the user's safety and the surrounding area (toilet, bathroom, etc.) may be corroded.
In addition to the water-soluble thickener and acid, the liquid acidic detergent of the present invention can also contain a surfactant. Surfactants include anionic surfactants such as fatty acid salts, higher alcohol sulfates, liquid fatty oil sulfates, alkyl allyl sulfonates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, poly Nonionic surfactants such as oxyethylene sorbitan alkyl esters, acetylene alcohol, and acetylene glycol are listed. In addition, antifoaming agents, preservatives, abrasives, antisettling agents, chelating agents, anticorrosives, fragrances, and the like can be used in combination.
In order to obtain a cleaning effect, ease of handling (usability) and stability, the viscosity of the liquid acidic cleaning agent at 20 ° C. is preferably adjusted to 5 to 100 mPa · s, particularly 10 to 20 mPa · s.

When used for pharmaceutical or cosmetic applications, alcohol or an alcohol / water mixture is used as a solvent. Examples of such alcohol include ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-octanol and the like, but ethanol is preferable from the viewpoint of safety to human body and odor.
It is natural to use medicinal ingredients and cosmetic ingredients, but if necessary, surfactants similar to those described above can be added. Pigments, dyes, antifoaming agents, preservatives, abrasives, anti-settling agents, chelating agents, anticorrosives, fragrances and the like can be used in combination.

In addition to the components described above, a dispersant can be used for the purpose of improving the dispersibility of pigments and the like. As the dispersant, various low molecular weight water-soluble polymers known to be effective for dispersing pigments and the like can be used.
A typical example of the low molecular weight water-soluble polymer is an acrylic low molecular weight water-soluble polymer.

  When pH adjustment is necessary, examples of pH adjusters include alkali metal hydroxides and carbonates such as sodium and potassium, alkaline earth metal hydroxides such as calcium and magnesium, methylamine, monoethanolamine, Alkylamines such as dimethylamine, isopropylamine, dipropylamine, trimethylamine, monoethylamine, triethylamine, methylethylamine, monoisopropylamine, phentolamine, methylpropylamine, diisopropylamine, alkanolamines such as monoethanolamine, isopropanolamine, etc. Ammonia, pyridine, etc., among which alkali metal hydroxides and carbonates are preferred.

Next, the present invention will be described more specifically with reference to examples and comparative examples.
In the following examples, “%” means “wt%” and “ppm” means “wt ppm” unless otherwise indicated.

A synthesis example of ATBS of the present invention and a production example of an aqueous dispersion will be specifically described. The concentration (weight ppm) was quantified by HPLC.
HPLC conditions; Waters high performance liquid chromatograph column; GL Science ODS-3
Eluent: 0.03% aqueous trifluoroacetic acid / acetonitrile Eluent flow rate: 0.8 ml / min
Detection wavelength: 200 nm

○ Synthesis Example 1
Two glass reactors equipped with a stirrer and an inlet pipe and an outlet pipe were connected, acrylonitrile and fuming sulfuric acid were charged into the first reactor under the following conditions, and after mixing acrylonitrile and fuming sulfuric acid, Two reactors were fed. In the second reactor, isobutylene gas was blown into the mixture to synthesize the target product. The above reaction was carried out continuously.
The amount of acrylonitrile supplied was 11 mol and the amount of isobutylene supplied was 0.9 mol per mol of fuming sulfuric acid. During the reaction, the reaction solution was collected, the concentration of IBSA was measured by HPLC, and the supply amount of fuming sulfuric acid was adjusted as shown in Table 1.
In addition, the concentration of sulfur trioxide in fuming sulfuric acid is 0.6%, and the concentration is adjusted by mixing concentrated sulfuric acid after adding moisture brought from raw materials such as acrylonitrile to commercially available 20% fuming sulfuric acid. doing. The first reactor is maintained at −15 ° C. and the residence time is 10 minutes. The second reactor is maintained at 45 ° C. and the residence time is 90 minutes.
The ATBS slurry obtained in the above production was suction filtered with a glass filter to obtain a cake on the glass filter. The amount of acrylonitrile described in Table 1 with respect to the cake weight was poured into the cake and suction filtered again to wash the cake.
The cake was transferred to a tray and dried at a drying temperature of 80 ° C. for 90 minutes.
When the obtained ATBS powder was subjected to LC analysis and the concentration of IBSA was measured, the IBSA concentration was 60 ppm.

○ Synthesis Example 2
In the synthesis example 1, it manufactured by changing the conditions of a process into the conditions shown in Table 1. When the obtained ATBS powder was analyzed by HPLC, the IBSA concentration was 30 ppm by weight.

○ Synthesis Example 3
In the synthesis example 1, it manufactured by changing the conditions of each process into the conditions shown in Table 1. When the obtained ATBS powder was analyzed by HPLC, the IBSA concentration was 80 ppm by weight.

Comparative Comparative Example In Synthesis Example 1, the conditions of each step were changed to the conditions shown in Table 1 for production. When the obtained ATBS powder was analyzed by HPLC, the IBSA concentration was 200 ppm.

○ Production Example 1
916.8 g (equivalent to 80 mol%) of a 50 wt% aqueous solution obtained by neutralizing ATBS obtained in Synthesis Example 1 with sodium hydroxide, 65.2 g (equivalent to 10 mol%) of a 35 wt% aqueous solution of sodium acrylate Then, 18.0 g (corresponding to 10 mol%) of acrylic acid was mixed to prepare 1 kg of an aqueous solution having a monomer concentration of 50% by weight. This aqueous monomer solution was charged into a stainless steel dewar, and nitrogen bubbling was performed for 30 minutes while adjusting the temperature of the reaction vessel to 10 ° C. Next, 30 ppm of t-butyl hydroperoxide as a polymerization initiator (weight basis with respect to the total amount of all monomers, the same applies hereinafter), 200 ppm of sodium persulfate and 20 ppm of sodium erythorbate were added, and allowed to stand for 8 hours. In-place redox polymerization was performed. After the completion of the reaction for 8 hours, the produced hydrogel polymer was taken out from the reaction vessel, put into a chopper and chopped into ground meat. The chopped water-containing gel was dried with a hot air dryer, and further pulverized with a pulverizer to obtain a desired powdery copolymer.
The top peak molecular weight determined under GPC measurement conditions for this copolymer was 13.5 million.

○ GPC conditions Using an aqueous solution containing sodium sulfate (1.33 g / l) and sodium hydroxide (0.33 g / l) as a solute as a solvent, polyacrylic acid (AMERICA POLYMER STANDARDDS CORP. Molecular weight 9 million, 555 Calibration curves were created using 10,000, 1.14 million, 440,000, 131200, 7900, and 2400) as reference materials. The elution rate was 0.6 mL / min and the detector used was Tosoh RI detector TI-8020. The molecular weight of the peak top (inflection point) with the highest detection intensity was defined as the top peak molecular weight.

○ Production Example 2
A powdery copolymer was obtained in the same manner as in Production Example 1 except that ATBS was changed to that obtained in Synthesis Example 2 in Production Example 1. The top peak molecular weight determined under the GPC measurement conditions of this copolymer was 18 million.

○ Production Example 3
655.9 g (corresponding to 50 mol%) of a 50 wt% aqueous solution obtained by neutralizing ATBS obtained in Synthesis Example 1 with sodium hydroxide, 184.1 g (corresponding to 25 mol%) of a 35 wt% aqueous solution of sodium acrylate Then, 50.8 g (corresponding to 25 mol%) of acrylic acid and 119.2 g of pure water were mixed to prepare 1 kg of an aqueous solution having a monomer concentration of 44% by weight. This aqueous monomer solution was charged into a stainless dewar, and nitrogen bubbling was performed for 30 minutes while adjusting the temperature of the reaction vessel to 5 ° C. Next, 10 ppm of t-butyl hydroperoxide, 200 ppm of sodium persulfate and 20 ppm of sodium erythorbate were added as polymerization initiators, and left for 8 hours to conduct adiabatic static redox polymerization. After the completion of the reaction for 8 hours, the produced hydrogel polymer was taken out from the reaction vessel, put into a chopper and chopped into ground meat. The chopped water-containing gel was dried with a hot air dryer, and further pulverized with a pulverizer to obtain a desired powdery copolymer. The top peak molecular weight of this copolymer determined under GPC measurement conditions was 12.2 million.

○ Production Example 4
A powdery copolymer was obtained in the same manner as in Production Example 3 except that ATBS was changed to that obtained in Synthesis Example 3 in Production Example 3. The top peak molecular weight determined under the GPC measurement conditions of this copolymer was 1,080,000.

○ Comparative production example 1
A powdery copolymer was obtained in the same manner as in Production Example 1 except that ATBS was changed to that obtained in Comparative Synthesis Example in Production Example 1. The top peak molecular weight of this copolymer determined by GPC measurement conditions was 9,500,000.

○ Comparative Production Example 2
A powdery copolymer was obtained in the same manner as in Production Example 3 except that ATBS was changed to that obtained in Comparative Example in Production Example 3. The top peak molecular weight determined under the GPC measurement conditions of this copolymer was 8.7 million.

○ Physical property evaluation of aqueous thickener ○ Examples 1-4, Comparative Examples 1-3
Using the copolymers obtained in Production Examples 1 to 4 and Comparative Examples 1 to 3, physical properties as an aqueous thickener were tested according to the following method. The results are shown in Table 2.

1) Viscosity of 0.2 wt% aqueous solution 0.8 g of each polymer was added to 400 ml of pure water and stirred for 3 hours, and dissolved sufficiently to prepare an aqueous solution of 0.2 wt% aqueous thickener. The viscosity of this aqueous solution was measured with a B-type viscometer (manufactured by Tokyo Keiki Co., Ltd., model: BM type) at a rotor speed of 30 ° C. and 30 rpm.
2) pH
The pH of the 0.2 wt% aqueous solution prepared above was measured with a pH meter.
3) Insoluble matter 400 ml of the 0.2 wt% aqueous solution prepared above was filtered with an 83 mesh stainless steel standard sieve (JIS Z8801, inner diameter 200 mm), and the volume of the insoluble matter remaining on the sieve was measured. .

表２に示すように、製造例の水系増粘剤、比較製造例の増粘剤の水溶液粘度は、ＡＴＢＳ中に含まれるＩＢＳＡの濃度に相関していることがわかる。水溶液の濃度やｐＨは同一であるので、ＡＴＢＳ中のＩＢＳＡ濃度が低い程、増粘効果が大きくなることがわかる。

As shown in Table 2, it can be seen that the aqueous solution viscosity of the aqueous thickener of the production example and the thickener of the comparative production example correlate with the concentration of IBSA contained in the ATBS. Since the concentration and pH of the aqueous solution are the same, it can be seen that the lower the IBSA concentration in ATBS, the greater the thickening effect.

○ Evaluation of aqueous thickener ○ Examples 5-8, Comparative Examples 3-4
The aqueous thickeners obtained in Production Examples 1 to 4 and Comparative Production Examples 1 and 2 were sufficiently stirred at the concentrations shown in Table 3 in a 10% by weight hydrochloric acid aqueous solution and left for 2 days. A liquid acidic detergent of 10% by weight hydrochloric acid was used.
About each obtained liquid acidic cleaning agent, the viscosity was measured. The results are shown in Table 3. The viscosity was measured with a B-type viscometer under the conditions of 20 ° C. and 60 rpm.

表３から分かるように、本発明のＡＴＢＳを使用した水系増粘剤は、少ない添加量で大きな増粘効果が得られることがわかる。

As can be seen from Table 3, the aqueous thickener using the ATBS of the present invention can provide a large thickening effect with a small addition amount.

○ Production Example 5
40 g of ATBS obtained in Synthesis Example 1 is dissolved in 40 g of pure water, and a 16.25% aqueous sodium hydroxide solution is added to adjust the pH to 8 to 8.5. At this time, the liquid temperature is measured and cooled as necessary so as not to exceed 25 ° C. After adjusting the pH, pure water is added to obtain 146 g of an ATBS neutralized aqueous solution (30.3 wt%). In a separate container, 285.5 g of 40 wt% acrylamide aqueous solution, 46.7 g of 35 wt% aqueous solution of sodium acrylate, 110 g of ATBS neutralized aqueous solution, and 363.4 g of pure water are mixed. Adjust pH to 6.8-7.0 using ATBS or caustic soda. This monomer mixed solution is transferred to a polymerization vessel and nitrogen 2 L / min is blown into the vessel. After 1 hour, the liquid temperature is adjusted to 20 ° C. while continuing to blow nitrogen. To this solution, 0.39 ml of 100 ppm copper aqueous solution, 3.02 ml of 10% aqueous solution of 2,2′-azobis (2-methylpropaneamidine) dihydrochloride (V-50 manufactured by Wako Pure Chemical Industries), 1% ammonium persulfate Add 02 ml. After about 15 minutes, nitrogen blowing into the liquid is stopped and changed to blowing nitrogen 40 ml / min into the gas phase of the polymerization vessel.
After the copolymer gel is cooled, the gel is shredded using a meat chopper, and the resulting gel is dried at 80 ° C. for 3 hours. Further, the dried gel is applied to a pulverizer. The obtained powder was dissolved in pure water to prepare a 0.5 wt% aqueous solution. When the viscosity of the aqueous solution was measured with a B-type viscometer (manufactured by Tokyo Keiki Co., Ltd., model: BM type) at 30 ° C. and a rotor rotational speed of 30 rpm, it was 160 mPa · s. GPC measurement of this copolymer The top peak molecular weight determined under the conditions was 13.5 million.

○ Production Example 6
In Example 5, the same operation as in Production Example 5 was performed except that the ATBS used was changed to that obtained in Synthesis Example 2. The obtained powder was dissolved in pure water to prepare a 0.5 wt% aqueous solution, and the viscosity of this aqueous solution was measured to be 210 mPa · s. The top peak obtained under the GPC measurement conditions of this copolymer The molecular weight was 16.7 million.

○ Comparative Production Example 3
In Production Example 5, the same operation as in Production Example 5 was performed, except that the ATBS used was changed to that obtained in Synthesis Example 4. The obtained powder was dissolved in pure water to prepare a 0.5 wt% aqueous solution, and the viscosity of this aqueous solution was measured to be 95 mPa · s. The top peak obtained under the GPC measurement conditions of this copolymer The molecular weight was 7.8 million.

○ Comparative Production Example 4
In Comparative Production Example 3, a powdery copolymer was obtained in the same manner as in Comparative Production Example 1, except that 0.002 g of N, N-methylbisacrylamide was added as a crosslinking agent. The top peak molecular weight determined under GPC measurement conditions for this copolymer was 13.7 million.

○ Comparison of physical properties of aqueous thickener ○ Examples 9-10, Comparative Examples 5-6
The powders obtained in Production Examples 5 and 6 and Comparative Production Examples 3 and 4 were compared in terms of salt viscosity, water insoluble matter, and spinnability by the methods shown below, and are shown in Table 4.

Salt viscosity 2.26 g of the powder obtained by the above operation is placed in a 500 ml container, and 400 ml of pure water is added. After dissolving with a jar tester (rotation speed: 200 rpm, stirring time: 3.5 hours), 16 g of sodium chloride was added and stirred for another 30 minutes to obtain a salt viscosity measurement solution.
Viscosity was measured using a B-type viscometer with the solution temperature adjusted to 25 ° C.
○ Amount of water insoluble matter 0.5 g of the powder obtained by the above operation is placed in a 500 ml container, and 500 ml of pure water is added. It melt | dissolved with the jar tester (rotation speed 200rpm, stirring time 5 hours), and it was set as the insoluble matter amount measuring solution.
The insoluble matter amount was measured by pouring the above solution into an 80 mesh sieve and transferring the gel amount remaining on the sieve to a measuring cylinder after 10 minutes.
○ Spinnability 1.5 g of the powder obtained by the above operation is placed in a 500 ml container, and 500 ml of pure water is added. It melt | dissolved with the jar tester (rotation speed 200rpm, stirring time 5 hours), and it was set as the spinnability measurement solution.
In the measurement of the spinnability, the solution temperature was adjusted to 25 ° C., and the pulling-down rate was measured at 5 mm / second. The spinnability measuring apparatus used was a container in which a sample was placed on a pedestal whose descent rate was adjusted to 5 mm / second, and the lower end of a glass ball (diameter 10 mm) suspended from above the sample container was 27 mm below the sample liquid level. Soak until. In this state, the pedestal is lowered at a speed of 5 mm / sec. Measure the time required from when the lower end of the glass ball is separated from the sample liquid surface to when the kite is broken from the glass ball, and multiply the time by the descending speed of the pedestal (5 mm / sec). The thread property (mm) was used.

表４より、トップピーク分子量が同レベルであっても、架橋性単量体を用いた共重合体（比較製造例４）は、本願発明の共重合体（製造例５）より、粘度と曳糸性が低く、水性増粘液としての性能が劣った。これは、本願発明の共重合体が直鎖状であるのに対し、比較製造例４が分岐状であることに起因すると考えられる。

From Table 4, even if the top peak molecular weight is at the same level, the copolymer using the crosslinkable monomer (Comparative Production Example 4) has a viscosity and viscosity difference from the copolymer of the present invention (Production Example 5). The threadability was low, and the performance as an aqueous thickener was poor. This is thought to be due to the fact that the copolymer of the present invention is linear, whereas Comparative Production Example 4 is branched.

○ Production Example 7
40 g of ATBS obtained in Synthesis Example 2 is dissolved in 40 g of pure water, and a 16.25% aqueous sodium hydroxide solution is added to adjust the pH to 8-8.5. At this time, the liquid temperature is measured and cooled as necessary so as not to exceed 25 ° C. After adjusting the pH, pure water is added to make 146 g of an ATBS neutralized aqueous solution (30.3 wt%). In a separate container, 75 g of 40 wt% aqueous acrylamide solution, 342.9 g of 35 wt% aqueous solution of sodium acrylate, 133.3 g of ATBS neutralized aqueous solution, 10 g of N-isopropylacrylamide (N-iPrAAM), and 235 g of pure water are mixed. Adjust pH to 6.8-7.0 using ATBS or caustic soda. This monomer mixed solution is transferred to a polymerization vessel and nitrogen 2 L / min is blown into the vessel. After 1 hour, the liquid temperature is adjusted to 20 ° C. while continuing to blow nitrogen. To this solution is added 0.39 ml of 100 ppm copper aqueous solution, 3.02 ml of 10% V-50 aqueous solution, and 2.02 ml of 1% ammonium persulfate. After about 15 minutes, nitrogen blowing into the liquid is stopped and changed to blowing nitrogen 40 ml / min into the gas phase of the polymerization vessel.
After the polymerization gel cools, the gel is shredded using a meat chopper, and the resulting gel is dried at 80 ° C. for 3 hours. Further, the dried gel was applied to a pulverizer to obtain a powdery copolymer. The top peak molecular weight determined under GPC measurement conditions for this copolymer was 11 million.

○ Production Example 8
A copolymer powder was obtained in the same manner as in Production Example 7, except that N-isopropylacrylamide was changed to N-ethylacrylamide in Production Example 7. The top peak molecular weight determined under GPC measurement conditions for this copolymer was 11.7 million.

Example 9
A copolymer powder was obtained in the same manner as in Production Example 7 except that N-isopropylacrylamide was changed to N, N-diethylacrylamide in Production Example 7. It was. The top peak molecular weight determined under GPC measurement conditions for this copolymer was 11.8 million.

○ Comparative Production Example 5
A copolymer powder was obtained in the same manner as in Production Example 7, except that the ATBS used in Production Example 7 was changed to that obtained in the Comparative Synthesis Example. The top peak molecular weight of the copolymer determined under GPC measurement conditions was 8 million.

○ Examples 11-15, Comparative Examples 7-8
○ Ethanol viscosity of aqueous thickener The aqueous thickener of Production Examples 5 to 9 and the copolymer powder of Comparative Production Examples 3 and 5 were dissolved in pure water to prepare 0.2 wt% aqueous solution. The viscosity of the aqueous solution was measured with a B-type viscometer (manufactured by Tokyo Keiki Co., Ltd., model: BM type) at a rotor rotational speed of 30 ° C. and 30 rpm. Similarly, the obtained powder was dissolved in ethanol to prepare a 0.2 wt% aqueous solution. The viscosity of this ethanol solution was measured. The results are shown in Table 5.

表５から明らかなように、本発明の水系増粘剤は、水のみならずエタノール中でも増粘性に優れている。

As is apparent from Table 5, the aqueous thickener of the present invention is excellent in thickening not only in water but also in ethanol.

According to the present invention, it is possible to produce an aqueous thickener which is excellent in thickening of a solution showing strong acidity, a solution having a high salt concentration, and an alcoholic solution, and has good solubility because there is no undissolved part, etc., and easy handling. .
The aqueous thickener of the present invention makes it easy to use acidic cleaning solutions that remove dirt from bathroom tiles, washstands, toilets and toilet tiles in bathrooms, flocculants, and aqueous thickeners for medical and cosmetic use. Can be manufactured.

Claims (7)

The monomer (A) shown below is 15 to 80% by weight, the monomer (B) and / or the monomer (C) is essentially 20 to 85% by weight, and does not contain a crosslinkable monomer. An aqueous thickener which is a water-soluble copolymer obtained by radical copolymerization under conditions, and has a GPC top peak molecular weight of 2 million to 30 million based on polyacrylic acid.
Monomer (A); 2-acrylamido-2-methylpropanesulfonic acid and / or a salt thereof, wherein the content of 2-methyl-2-propenyl-1-sulfonic acid is 120 ppm by weight or less.
Monomer (B); (meth) acrylic acid and / or a salt thereof.
Monomer (C): monofunctional acrylamide or acrylate ester in which an alkyl group may be bonded to the N atom. The aqueous thickener according to claim 1, wherein the monomer (A) is produced through the following first to fourth steps.
1st process; The process of manufacturing the liquid mixture of acrylonitrile and fuming sulfuric acid.
Second step: A mixture of isobutylene and the mixed liquid produced in the first step are mixed and contacted, and 2-methyl-2-propenyl-1-sulfonic acid is 12000 ppm by weight or less of 2-acrylamido-2-methylpropanesulfonic acid. A step of obtaining an acrylonitrile slurry liquid.
Third step: A step of solid-liquid separation of the slurry liquid obtained in the second step to obtain a crude cake of 2-acrylamido-2-methylpropanesulfonic acid, and then washing the crude cake with acrylonitrile.
Fourth step: A step of drying the washed coarse cake obtained in the third step. The aqueous thickener according to claim 1 or 2, wherein the monomer (C) is a monomer selected from acrylamide, N-alkylacrylamide, and N, N-dialkylacrylamide. The aqueous thickener according to any one of claims 1 to 3, wherein the content of 2-methyl-2-propenyl-1-sulfonic acid in the monomer (A) is 60 ppm by weight or less. The aqueous thickener according to any one of claims 1 to 4, wherein the content of 2-methyl-2-propenyl-1-sulfonic acid in the monomer (A) is 30 ppm by weight or less. The method for producing an aqueous thickener according to any one of claims 1 to 5, wherein the monomers (A), (B) and / or (C) are gel-polymerized. An aqueous thickener containing the aqueous thickener according to any one of claims 1 to 5 and a mineral acid or organic acid, or an alcohol as essential components.