JP2009197172A - Manufacturing method of granular carboxyl-containing polymer and granular carboxyl-containing polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple manufacturing method of a granular carboxyl-containing polymer that has a specific middle particle size, is high in bulk density, and can swell in water. <P>SOLUTION: The manufacturing method of a granular carboxyl-containing polymer comprises mixing a carboxyl-containing polymer with an organic solvent having a specific dielectric constant of 1.9-20 to stir and granulate. The manufacturing method can provide a granular carboxyl-containing polymer that hardly generates lumps, hardly crumbles even after aggregation, is excellent in the swellability in water, does not fly up into a dust, and is excellent in workability, compared with a micro-powdery carboxyl-containing polymer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a granular carboxyl group-containing polymer and a granular carboxyl group-containing polymer obtained thereby. More specifically, the present invention relates to a method for producing a granular carboxyl group-containing polymer that can be suitably used as a thickener for cosmetics and the like, and a granular carboxyl group-containing polymer obtained thereby.

  Carboxy group-containing polymers used for thickeners such as cosmetics, moisturizers such as poultices, suspension stabilizers such as emulsifiers and suspensions, etc. include cross-linked carboxyl group-containing polymers and alkyl-modified carboxyl group-containing polymers. Polymers and the like are known. Examples of the crosslinked carboxyl group-containing polymer include a copolymer of an α, β-unsaturated carboxylic acid such as acrylic acid and polyallyl ether (see Patent Document 1), an α, β-unsaturated carboxylic acid and hexa A copolymer with allyltrimethylenetrisulfone (see Patent Document 2), a copolymer with an α, β-unsaturated carboxylic acid and glycidyl methacrylate (see Patent Document 3), an α, β-unsaturated carboxylic acid, Copolymer with pentaerythritol allyl ether (see Patent Document 4, Patent Document 5 and Patent Document 6), Copolymer of α, β-unsaturated carboxylic acid, (meth) acrylic acid ester and pentaerythritol allyl ether ( Patent Document 7 and Patent Document 8) are known.

  As the alkyl-modified carboxyl group-containing polymer, for example, a copolymer of (meth) acrylic acid and (meth) acrylic acid alkyl ester is known. Specifically, for example, a copolymer obtained by reacting a specific amount of an olefinically unsaturated carboxylic acid monomer with a specific amount of (meth) acrylic acid alkyl ester (the alkyl group has 10 to 30 carbon atoms) ( Patent Document 9), a copolymer obtained by reacting an olefinic unsaturated carboxylic acid monomer and a (meth) acrylic acid alkyl ester (the alkyl group has 8 to 30 carbon atoms) (see Patent Document 10), etc. Are known.

  In order to use a carboxyl group-containing polymer such as a crosslinked carboxyl group-containing polymer or an alkyl-modified carboxyl group-containing polymer for the above-mentioned use, first, a uniform aqueous dispersion of the carboxyl group-containing polymer is prepared, and then It is necessary to neutralize with an alkali to obtain a neutralized viscous liquid of about 0.1 to 1% by mass. However, since the carboxyl group-containing polymer is usually a fine powder, a lump (maco) is likely to occur when dispersed in water. Once Mamako is formed, a gel-like layer is formed on the surface thereof, so that the speed at which water penetrates into the inside becomes slow and it is difficult to obtain a uniform aqueous dispersion.

  Therefore, when preparing an aqueous dispersion of a carboxyl group-containing polymer, in order to prevent the formation of mamako, an operation with poor production efficiency is performed in which the carboxyl group-containing polymer powder is gradually added to water under high-speed stirring. In some cases, special mixing equipment is required to prevent the formation of mamako.

  Further, the carboxyl group-containing polymer is usually fine powder and easily charged, so that the powder formation is intense. Therefore, the carboxyl group-containing polymer is not only difficult to handle but also has a disadvantage that it is not preferable in the working environment. Further, the fine powder of the carboxyl group-containing polymer has problems such as a small bulk density, an increase in transportation cost, and a large storage space.

  Therefore, a method for producing a granular carboxyl group-containing polymer has been studied.

  Usually, a granulator is used for granulating the powder. Granulators are roughly classified into granulation methods, mixed granulation, forced granulation, and heat-utilization granulation.

  Examples of the granulator for mixed granulation include a fluidized bed granulator and a rolling granulator. The powder is made to flow by an air flow, a stirring blade, rolling, etc. Spray uniformly to produce granules. When these granulators for mixing granulation are applied to carboxyl group-containing polymers, the carboxyl group-containing polymers are very fine in particle size and low in bulk density, so they must be made to flow by air flow, stirring blades, or rolling. Is difficult. The liquid used as the binder is preferably water or a polar organic solvent. However, when water or a polar organic solvent is sprayed while flowing the carboxyl group-containing polymer, the carboxyl group-containing polymer becomes sticky and the inner wall of the granulator or It adheres to the nozzle which sprays a binder, or a carboxyl group-containing polymer adheres and forms a big lump.

  Examples of the granulator for forced granulation include a compression molding granulator and an extrusion granulator. As an example of granulating a carboxyl group-containing polymer using forced granulation, there is a method of compressing and pulverizing a fine powder with a compression molding apparatus (see Patent Document 11). However, this method has a problem that the carboxyl group-containing polymer is excessively compressed by the pressure of the compression molding apparatus, and the swelling property of the resulting granular carboxyl group-containing polymer in water deteriorates.

  An example of the granulator for heat-using granulation is a spray dryer. However, according to this method, it is necessary to dilute the carboxyl group-containing polymer with water or an organic solvent to a sprayable viscosity, and the resulting granules are not porous, resulting in poor solubility in water. Have problems such as.

  On the other hand, as a granulating method not using the above granulator, for example, a method of granulating a fine powder of a polymer flocculant and steam of steam (see Patent Document 12), a water-soluble polymer fine powder is used. After dispersing in an organic solvent, water is added and granulated (see Patent Document 13), and a lubricant and water are simultaneously and continuously supplied to a finely powdered water-soluble polymer substance to form a gel body. A method of pulverizing after granulation (see Patent Document 14) is known.

  However, in the method described in Patent Document 12, when water condensed with steam of steam comes into contact with the carboxyl group-containing polymer, the carboxyl group-containing polymer swells in water, and the granules finally obtained become nonporous. Therefore, in the method in which the solubility in water is deteriorated and the powder is dropped and brought into contact with steam of steam, the carboxyl group-containing polymer has poor fluidity and is difficult to drop uniformly. There is a problem that a large amount of dust may be generated when the body is dropped.

  The method described in Patent Document 13 has a problem that the water-containing gel is agglomerated when water is added after being dispersed in an organic solvent.

  The method described in Patent Document 14 contains an unnecessary lubricant depending on the intended use, and is granulated through a gel body, so that the resulting granules are not porous, so the solubility in water is poor. There is a problem.

U.S. Pat. No. 2,923,629 US Pat. No. 2,958,679 JP 58-84819 A US Pat. No. 5,342,911 US Pat. No. 5,663,253 US Pat. No. 4,996,274 Japanese Patent Publication No. 5-39966 Japanese Patent Publication No. 60-12361 Japanese Patent Laid-Open No. 51-6190 US Pat. No. 5,004,598 International Publication No. 03/016382 Pamphlet JP-A-52-2877 JP-A-52-136262 JP-A-3-143605

  An object of the present invention is to provide a method for easily producing a granular carboxyl group-containing polymer having a specific medium particle diameter, a large bulk density, and easily swelled in water.

The present invention has been completed by finding that a granular carboxyl group-containing polymer can be obtained by mixing and stirring a carboxyl group-containing polymer with an organic solvent having a specific dielectric constant. That is, the present invention
Item 1. A method for producing a granular carboxyl group-containing polymer, comprising mixing and stirring a carboxyl group-containing polymer and an organic solvent having a relative dielectric constant of 1.9 to 20, followed by granulation.

  Item 2. Item 1. The carboxyl group-containing polymer is a carboxyl group-containing polymer obtained by polymerizing a monomer component having an α, β-unsaturated carboxylic acid as a main constituent monomer in an inert solvent. The manufacturing method of the granular carboxyl group containing polymer of description.

  Item 3. The manufacturing method of the granular carboxyl group-containing polymer of claim | item 1 or 2 whose usage-amount of an organic solvent is 150-400 mass parts with respect to 100 mass parts of carboxyl group-containing polymers.

  Item 4. Item 1. The mixture according to Item 1 to 3, wherein a carboxyl group-containing polymer and an organic solvent having a relative dielectric constant of 1.9 to 20 are mixed, stirred and granulated, and then the particle size is adjusted by a granulator. The manufacturing method of the granular carboxyl group containing polymer of any one of Claims 1.

Item 5. A granular carboxyl group-containing polymer obtained by the production method according to any one of Items 1 to 4,
1) The median particle size is 200 to 800 μm,
2) Bulk density is 0.20 g / ml or more,
3) After putting the granular carboxyl group-containing polymer into the water at 25 ° C. which is allowed to stand so as to be 0.5% by mass with respect to water, all the granular carboxyl group-containing polymer swells. Takes less than 30 minutes,
A granular carboxyl group-containing polymer characterized by having the following characteristics:

  According to the production method of the present invention, it is possible to obtain a granular carboxyl group-containing polymer having a specific medium particle diameter, a large bulk density, and a particle shape that is less likely to collapse after granulation. In addition, the granular carboxyl group-containing polymer obtained by the production method of the present invention is dissolved in water and then neutralized with an alkali compound such as sodium hydroxide or triethanolamine, so that the surface smoothness can be obtained in a short time. A neutralized viscous liquid having excellent thickening and transparency can be obtained.

  The method for producing a granular carboxyl group-containing polymer of the present invention is characterized in that a carboxyl group-containing polymer and an organic solvent having a relative dielectric constant of 1.9 to 20 are mixed and stirred for granulation. As the carboxyl group-containing polymer, for example, a carboxyl group-containing polymer containing α, β-unsaturated carboxylic acids as main constituent monomer components is preferably used.

  Examples of the carboxyl group-containing polymer having α, β-unsaturated carboxylic acids as main constituent monomer components dissolve monomer components having α, β-unsaturated carboxylic acids as main constituent monomers, for example. And what is obtained by superposing | polymerizing the monomer component which uses (alpha), (beta) -unsaturated carboxylic acid as a main component monomer in the inert solvent which does not melt | dissolve a carboxyl group-containing polymer is used preferably. More specifically, crosslinking obtained by polymerizing an α, β-unsaturated carboxylic acid and a compound having two or more ethylenically unsaturated groups in an inert solvent in the presence of a radical polymerization initiator. Type carboxyl group-containing polymer: α, β-unsaturated carboxylic acid and (meth) acrylic acid alkyl ester having an alkyl group having 10 to 30 carbon atoms in an inert solvent in the presence of a radical polymerization initiator And an alkyl-modified carboxyl group-containing polymer obtained by polymerizing the polymer.

  The α, β-unsaturated carboxylic acids for producing the crosslinked carboxyl group-containing polymer are not particularly limited, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and fumaric acid. α, β-unsaturated carboxylic acid; α, β- such as methyl acrylate, ethyl acrylate, octyl acrylate, lauryl acrylate, myristyl acrylate, behenyl acrylate, lauryl methacrylate, myristyl methacrylate, behenyl methacrylate Unsaturated carboxylic acid alkyl ester etc. are mentioned, These may be used independently, respectively and may use 2 or more types together.

  In the present specification, acrylic and methacryl may be collectively referred to as (meth) acryl.

  When the crosslinked carboxyl group-containing polymer is produced, the amount of α, β-unsaturated carboxylic acids used is preferably 6 to 25 parts by volume with respect to 100 parts by volume of the inert solvent described later. 22 volume parts is more preferable, and 13 to 20 volume parts is even more preferable. When the amount of α, β-unsaturated carboxylic acid used is less than 6 parts by volume, the obtained amount of the resulting crosslinked carboxyl group-containing polymer is small, which is not economical. In addition, when the amount of α, β-unsaturated carboxylic acid used exceeds 25 parts by volume, as the reaction proceeds, the cross-linked carboxyl group-containing polymer precipitates and it becomes difficult to uniformly stir, thereby controlling the reaction. Becomes difficult.

  The compound having two or more ethylenically unsaturated groups is not particularly limited. For example, ethylene glycol, propylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, glycerin, polyglycerin, trimethylolpropane, pentaerythritol, Acrylic esters having two or more substituted polyols such as saccharose and sorbitol; Allyl ethers having two or more substituted polyols; diallyl phthalate, triallyl phosphate, allyl methacrylate, tetraallyloxyethane, triallyl cyanurate, adipine Examples thereof include divinyl acid, vinyl crotonate, 1,5-hexadiene, divinylbenzene and the like. Among them, since a neutralized viscous liquid having a high viscosity can be obtained in a small amount and high suspension stability can be imparted to an emulsion, suspension, etc., pentaerythritol allyl ether and polyallyl saccharose are preferred. Used.

  The amount of the compound having two or more ethylenically unsaturated groups is preferably 0.01 to 2 parts by mass, and 0.3 to 1 with respect to 100 parts by mass of the α, β-unsaturated carboxylic acids. More preferably, it is 5 parts by mass. When the amount of the compound having two or more ethylenically unsaturated groups is less than 0.01 parts by mass, the viscosity of the neutralized viscous liquid prepared from the obtained granular carboxyl group-containing polymer may be lowered. . When the amount of the compound having two or more ethylenically unsaturated groups is more than 2 parts by mass, an insoluble gel is likely to be formed in the neutralized viscous liquid prepared from the obtained granular carboxyl group-containing polymer. There is a fear.

  The α, β-unsaturated carboxylic acids for producing the alkyl-modified carboxyl group-containing polymer are not particularly limited, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and fumaric acid. These may be used alone or in combination of two or more.

  When the alkyl-modified carboxyl group-containing polymer is produced, the amount of α, β-unsaturated carboxylic acids used is preferably 6 to 25 parts by volume with respect to 100 parts by volume of the inert solvent described later. 22 volume parts is more preferable, and 13 to 20 volume parts is even more preferable. When the amount of α, β-unsaturated carboxylic acid used is less than 6 parts by volume, the obtained amount of the resulting alkyl-modified carboxyl group-containing polymer is small, which is not economical. In addition, when the amount of α, β-unsaturated carboxylic acid used exceeds 25 parts by volume, as the reaction proceeds, an alkyl-modified carboxyl group-containing polymer precipitates, making it difficult to stir uniformly, and controlling the reaction. Becomes difficult.

  The (meth) acrylic acid alkyl ester having 10 to 30 carbon atoms of the alkyl group refers to an ester of (meth) acrylic acid and a higher alcohol having 10 to 30 carbon atoms of the alkyl group, for example, List esters of (meth) acrylic acid and stearyl alcohol, esters of (meth) acrylic acid and eicosanol, esters of (meth) acrylic acid and behenyl alcohol, and esters of (meth) acrylic acid and tetracosanol. Can do. Among these, the neutralized viscous liquid of the obtained granular carboxyl group-containing copolymer and the viscosity characteristics and texture of the liquid in the presence of an electrolyte are excellent, and thus stearyl methacrylate, eicosanyl methacrylate, and behenyl methacrylate. And tetracosanyl methacrylate is preferably used. In addition, as a (meth) acrylic-acid alkylester whose carbon number of an alkyl group is 10-30, you may use commercial items, such as brand name Blemmer VMA70 by Nippon Oil & Fat Co., Ltd., for example.

  The amount of alkyl (meth) acrylate alkyl ester having 10 to 30 carbon atoms in the alkyl group is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of α, β-unsaturated carboxylic acids. It is more preferable that it is 1-10 mass parts. When the amount of alkyl (meth) acrylic acid alkyl ester having 10 to 30 carbon atoms in the alkyl group is less than 0.5 parts by mass with respect to 100 parts by mass of the α, β-unsaturated carboxylic acid, it is obtained. The neutralized viscous liquid of the resulting granular carboxyl group-containing copolymer may have insufficient transmittance in the presence of an electrolyte. On the other hand, if it exceeds 20 parts by mass, the resulting granular carboxyl group-containing copolymer There is a risk of impairing the solubility of the polymer in water.

  The radical polymerization initiator is not particularly limited, and examples thereof include α, α′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, dimethyl-2,2′-azo. Examples thereof include bisisobutyrate, benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, and tertiary butyl hydroperoxide.

  The amount of radical polymerization initiator used is preferably 0.01 to 0.45 parts by mass, and 0.01 to 0.35 parts by mass with respect to 100 parts by mass of α, β-unsaturated carboxylic acids. It is more preferable. When the amount of the radical polymerization initiator used is less than 0.01 parts by mass, the reaction rate becomes slow, which may not be economical. Moreover, when the usage-amount of a radical polymerization initiator exceeds 0.45 mass part, since reaction rate becomes quick, control of reaction becomes difficult.

  The inert solvent dissolves α, β-unsaturated carboxylic acids, compounds having two or more ethylenically unsaturated groups, or (meth) acrylic acid alkyl esters having 10-30 carbon atoms. It refers to a solvent that does not dissolve the resulting carboxyl group-containing polymer.

  Examples of the inert solvent include normal pentane, normal hexane, normal heptane, normal octane, isooctane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, chlorobenzene, ethylene dichloride, ethyl acetate, acetic acid. Examples include isopropyl, ethyl methyl ketone, and isobutyl methyl ketone. These may be used alone or in combination of two or more. Among these, ethylene dichloride and normal hexane are preferably used from the viewpoint of stable quality and easy availability.

  When polymerizing the α, β-unsaturated carboxylic acid and a compound having two or more ethylenically unsaturated groups, or the α, β-unsaturated carboxylic acid and the alkyl group have 10 to 30 carbon atoms ( The atmosphere when polymerizing the (meth) acrylic acid alkyl ester is preferably an inert gas atmosphere such as nitrogen gas or argon gas.

  The reaction temperature is 50 to 90 ° C., preferably 55 to 75 ° C. from the viewpoint of suppressing an increase in the viscosity of the reaction solution and facilitating the reaction control.

  The reaction time varies depending on the reaction temperature and cannot be determined unconditionally, but is usually 2 to 10 hours.

  After completion of the reaction, the reaction solution is heated to 80 to 130 ° C. to volatilize and remove the inert solvent, whereby a carboxyl group-containing polymer as a white fine powder can be obtained. When the heating temperature is less than 80 ° C, drying may take a long time. When the heating temperature exceeds 130 ° C, the surface of the neutralized viscous liquid prepared from the granular carboxyl group-containing polymer obtained is smooth. May get worse.

  In the method for producing a granular carboxyl group-containing polymer of the present invention, the granular carboxyl group-containing polymer has, for example, a carboxyl group-containing polymer obtained as described above and a relative dielectric constant of 1.9-20. It can be produced by mixing and stirring an organic solvent and granulating the carboxyl group-containing polymer. Here, the relative dielectric constant is a value when measured at a temperature of 20 to 25 ° C.

  The method for granulating the carboxyl group-containing polymer is not particularly limited. For example, a method of adding a carboxyl group-containing polymer to an organic solvent having a relative dielectric constant of 1.9 to 20, mixing and stirring; Examples thereof include a method of adding an organic solvent having a relative dielectric constant of 1.9 to 20 to the group-containing polymer, and mixing and stirring.

  The relative permittivity of the organic solvent used in the present invention is 1.9 to 20, preferably 3 to 14, and more preferably 4 to 13.1. When the relative dielectric constant of the organic solvent to be used is less than 1.9, the carboxyl group-containing polymer is hardly granulated. Moreover, when the relative dielectric constant of the organic solvent used exceeds 20, the carboxyl group-containing polymer needs to be agglomerated and pulverized, and the process becomes complicated.

  Examples of the organic solvent having a relative dielectric constant of 1.9 to 20 used in the present invention include aliphatic hydrocarbon solvents such as n-heptane and n-octane; alicyclic hydrocarbon solvents such as cyclohexane; benzene Aromatic hydrocarbon solvents such as toluene, o-xylene, m-xylene, p-xylene, o-cresol, m-cresol, p-cresol; dichloromethane, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1 Halogen solvents such as 1,2-dichloroethane, 1,1,1-trichloroethane, trichloroethylene and chlorobenzene; ether solvents such as dimethyl ether, 1,2-dimethoxyethane, dioxane and tetrahydrofuran; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone System solvents: ethyl acetate, butyl acetate, etc. Ester-based solvents; 2-propanol, 1-butanol, 2-methoxyethanol, benzyl alcohol, alcohol solvents such as cyclohexanol. These may be used alone or in combination of two or more. Among these, ester solvents, ketone solvents, and mixed solvents of ester solvents and aliphatic hydrocarbon solvents are preferably used, and in particular, ethyl acetate, methyl isobutyl ketone, and a mixture of ethyl acetate and n-heptane. A solvent is more preferably used.

Moreover, in this invention, the organic solvent which is not contained in the range whose relative dielectric constant is 1.9-20 can also be used together. In that case, according to the following formula, it is necessary to adjust the usage amount appropriately so that the relative dielectric constant (calculated value) is in the range of 1.9-20. However, the sum of Σ is epsilon _i d _i, epsilon _i denotes the dielectric constant, the mass ratio of the organic solvent used together in an organic solvent to the total mass of d _i is the use of organic solvents in combination.

Relative permittivity (calculated value) = Σ (ε _i d _i )
The organic solvent that can be used in combination is not particularly limited as long as the solvent has a relative dielectric constant (calculated value) after mixing of 1.9 to 20 as described above. Specific examples of organic solvents that can be used in combination include aliphatic hydrocarbon solvents such as n-pentane and n-hexane; nitrile solvents such as acetonitrile and propionitrile; carbonate solvents such as ethylene carbonate; methanol, ethanol, Examples include alcohol solvents such as 2-ethoxyethanol and 1,2-propanediol. These may be used alone or in combination of two or more.

  Since the amount of the organic solvent having a relative dielectric constant of 1.9 to 20 is determined depending on the organic solvent to be used, it cannot be generally stated, but it is 150 to 400 parts by mass with respect to 100 parts by mass of the carboxyl group-containing polymer. It is preferable that it is 150 to 300 parts by mass. When the usage-amount of the organic solvent whose relative dielectric constant is 1.9-20 is less than 150 mass parts, since there is little solvent amount, there exists a possibility that it may become difficult to granulate a carboxyl group-containing polymer. Moreover, when it exceeds 400 mass parts, when drying after granulating, it may take time and there exists a possibility that it may become economical. Specifically, with respect to 100 parts by mass of the carboxyl group-containing polymer, for example, 150 to 300 parts by mass for ethyl acetate and 250 to 300 for an ethyl acetate / n-heptane mixed solvent (mass ratio 0.5 / 0.5). In the case of 300 parts by mass and methyl isobutyl ketone, 150 to 300 parts by mass are preferably used.

  When an organic solvent having a relative dielectric constant of 1.9 to 20 is used when producing the carboxyl group-containing polymer, the slurry obtained after the completion of the polymerization reaction is used as it is or, if necessary, the organic solvent. The granular carboxyl group-containing polymer of the present invention can also be obtained by adjusting the amount, stirring and granulating.

  The reason why a granular carboxyl group-containing polymer can be obtained by mixing, stirring and granulating a carboxyl group-containing polymer and an organic solvent having a relative dielectric constant of 1.9 to 20 as described above is obvious. However, it is considered that the particles are granulated by binding an organic solvent having a relative dielectric constant of 1.9 to 20 as a binder.

  After mixing a carboxyl group-containing polymer and an organic solvent having a relative dielectric constant of 1.9 to 20, if necessary, it is passed through a sieve having an arbitrary opening, so that a granular shape adjusted to a desired intermediate particle size is obtained. A carboxyl group-containing polymer can be obtained.

  Moreover, it is preferable to adjust a particle diameter with a wet extrusion granulator from a viewpoint of productivity. Examples of the wet extrusion granulator include a wet extrusion granulator such as a twin dome gran series (Fuji Powdal Co., Ltd.); a cylindrical granulator such as a basket ruser series (Fuji Paudal Co., Ltd.), and the like. .

  In the method for producing a granular carboxyl group-containing polymer of the present invention, it is desirable to dry the granulated product of the carboxyl group-containing polymer obtained above.

  Although the drying apparatus used for drying is not specifically limited, For example, a vacuum dryer can be mentioned. As drying temperature, it is preferable that it is 30-130 degreeC, and it is more preferable that it is 50-110 degreeC. If the drying temperature is less than 30 ° C, drying may take a long time. If the drying temperature exceeds 130 ° C, the solubility of the resulting granular carboxyl group-containing polymer in water may be impaired. The liquid content after drying is preferably less than 5% by mass from the viewpoint of preventing agglomeration of the granular carboxyl group-containing polymer during long-term storage.

  In this way, the granular carboxyl group-containing polymer of the present invention can be obtained. Further, the polymer is classified using a sieve having a desired mesh size to remove the coarse powder, thereby obtaining a desired medium particle size. You can also.

The granular carboxyl group-containing polymer obtained by the production method of the present invention preferably has the following characteristics.
1) The median particle size is 200 to 800 μm,
2) Bulk density is 0.20 g / ml or more,
3) After putting the granular carboxyl group-containing polymer into the water at 25 ° C. which is allowed to stand so as to be 0.5% by mass with respect to water, all the granular carboxyl group-containing polymer swells. It takes 30 minutes or less.

  The median particle diameter of the granular carboxyl group-containing polymer of the present invention is preferably 200 to 800 μm, and more preferably 300 to 600 μm. When the median particle diameter is less than 200 μm, dust may easily stand up during use. On the other hand, when the median particle diameter exceeds 800 μm, the speed of swelling with respect to water may be reduced. In the present invention, the “median particle diameter” is a value measured by a measurement method described later.

  The bulk density of the granular carboxyl group-containing polymer of the present invention is preferably 0.20 g / ml or more, more preferably 0.20 to 0.60 g / ml, and 0.22 to 0.55 g. / Ml is particularly preferred. When the bulk density is less than 0.20 g / ml, it cannot be said that the bulk density is sufficiently large compared to the conventional carboxyl group-containing polymer, and solves problems such as an increase in transportation costs and a large storage space. It wo n’t happen. In the present invention, the “bulk density” is a value measured by a measurement method described later.

  The granular carboxyl group-containing polymer of the present invention was poured into 25 ° C. standing water so that the polymer was 0.5% by mass with respect to water, and then the swelling state of the polymer was visually observed. It is observed that the time required for the entire polymer to swell is preferably 30 minutes or less, and more preferably 30 to 1 minute. When the time required for the entire polymer to swell exceeds 30 minutes, it cannot be said that the swelling property is sufficiently good as compared with the conventional carboxyl group-containing polymer. The detailed measurement method is a value measured by the measurement method described later.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[Measuring method]
About the granular crosslinked carboxyl group-containing polymer obtained in each Example and Comparative Example, the median particle size, bulk density, and time required for swelling were evaluated by the following methods. The obtained results are shown in Table 1.

(1) Median particle size In the present invention, the “median particle size” is obtained by sequentially integrating the mass of particles remaining on each sieve when the granular carboxyl group-containing polymer is classified with a sieve. The particle diameter corresponding to the mesh opening when the accumulated mass reaches 50 mass% of the total mass of the particles. More specifically, seven standard sieves (apertures 850 μm, 500 μm, 355 μm, 300 μm, 250 μm, 180 μm, 106 μm) defined in JIS-Z8801-1982 and a tray are prepared. A large sieve is sequentially laminated, and 100 g of the granular carboxyl group-containing polymer is put on the sieve having the first opening, and is vibrated for 10 minutes using a low-tap sieve vibrator, and the particles remaining on each sieve are weighed. The particle diameter obtained by calculating the particle diameter corresponding to the sieve opening when the integrated mass obtained by sequential integration reaches 50% by mass of the total mass of the particles is calculated by the following equation: And
Median particle size (μm) = (50−A) / (C−A) × (D−B) + B

  In the formula, A is obtained by integrating the mass of the granular carboxyl group-containing polymer remaining on the sieve sequentially from the sieve having a coarse mesh, and the accumulated mass is less than 50 mass% of the total mass, and the most is 50 mass%. The integrated value (g) up to the nearest sieve. C accumulates the mass of the particles remaining on the sieve sequentially from the sieve having a coarse mesh, and the accumulated mass is 50 mass% or more of the total mass of the particles and the accumulated value up to the sieve closest to 50 mass% ( g). D is the sieve opening (μm) when the integrated value of A is obtained, and B is the sieve opening (μm) when the integrated value of C is obtained.

(2) Bulk density In the present invention, the “bulk density” refers to a value obtained by dividing the mass of the granular carboxyl group-containing polymer by the volume of the polymer of the mass. More specifically, 10 g of the granular carboxyl group-containing polymer was added within 20 seconds from the height of 5 cm above the 50 ml empty graduated cylinder, and then the volume (ml) occupied by the granular carboxyl group-containing polymer was measured. And a value calculated by dividing 10 g of the polymer by the volume (ml) occupied by the granular carboxyl group-containing polymer.

(3) Time required for swelling 150 g of water is put into a 200 ml beaker, and the temperature of water is adjusted to 25 ° C. With this still, 0.75 g of the granular carboxyl group-containing polymer is added, and the time required for all of the polymer to swell to the center is measured. The determination that the granular carboxyl group-containing polymer is swollen in water is made by visually judging that the white polymer swells in water and becomes white translucent during drying.

[Production Example 1]
In a 500 ml four-necked flask equipped with a stirrer, thermometer, nitrogen blowing tube and cooling tube, acrylic acid 45 g (42.9 ml), pentaerythritol allyl ether 0.24 g, α, α′-azobisisobutyrate 0.153 g of ronitrile and 150 g (223.9 ml) of normal hexane were charged. Subsequently, after stirring and mixing uniformly, nitrogen gas was blown into the solution in order to remove oxygen present in the upper space of the reaction vessel, the raw material, and the solvent. Subsequently, it was made to react for 4 hours, hold | maintaining at 60-65 degreeC under nitrogen atmosphere.

  After completion of the reaction, the produced slurry was heated to 90 ° C. to distill off normal hexane, and further dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 41 g of a white fine powder of a crosslinked carboxyl group-containing polymer. It was.

[Example 1]
100 g of a crosslinked carboxyl group-containing polymer obtained in the same manner as in Production Example 1 and 250 g of ethyl acetate (relative dielectric constant: 6.0) were added to a table type kneader (Irie Trading Co., Ltd., PNV-1 type). ) To obtain a granulated product of a crosslinked carboxyl group-containing polymer. The obtained granulated product is subjected to wet extrusion using a twin dome gran test machine (manufactured by Fuji Paudal Co., Ltd., model MG-55, dome die opening 1.0 mm, opening degree 35.4%) to obtain particles. The diameter was adjusted. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 98 g of a granular crosslinked carboxyl group-containing polymer.

  The above items were evaluated for the obtained granular crosslinked carboxyl group-containing polymer. The results are shown in Table 1.

[Example 2]
A mixed solvent of 100 g of a crosslinked carboxyl group-containing polymer obtained in the same manner as in Production Example 1, 120 g of ethyl acetate (relative permittivity: 6.0) and 120 g of n-heptane (relative permittivity: 1.9) (Relative dielectric constant (calculated value): 4.0) is mixed and stirred using a table type kneader (manufactured by Irie Trading Co., Ltd., PNV-1 type), and a granulated product of a crosslinked carboxyl group-containing polymer. Got. The obtained granulated product is subjected to wet extrusion using a twin dome gran test machine (manufactured by Fuji Paudal Co., Ltd., model MG-55, dome die opening 1.0 mm, opening degree 35.4%) to obtain particles. The diameter was adjusted. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 95 g of a granular crosslinked carboxyl group-containing polymer.

  The above items were evaluated for the obtained granular crosslinked carboxyl group-containing polymer. The results are shown in Table 1.

[Example 3]
A cross-linked carboxyl group-containing polymer 100 g obtained in the same manner as in Production Example 1 and 250 g of methyl isobutyl ketone (MIBK, relative dielectric constant: 13.1) were added to a table type kneader (manufactured by Irie Trading Co., Ltd., PNV). -1 type) was mixed and stirred to obtain a granulated product of a crosslinked carboxyl group-containing polymer. The obtained granulated product is subjected to wet extrusion using a twin dome gran test machine (manufactured by Fuji Paudal Co., Ltd., model MG-55, dome die opening 1.0 mm, opening degree 35.4%) to obtain particles. The diameter was adjusted. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 98 g of a granular crosslinked carboxyl group-containing polymer.

  The above items were evaluated for the obtained granular crosslinked carboxyl group-containing polymer. The results are shown in Table 1.

[Comparative Example 1]
100 g of a crosslinked carboxyl group-containing polymer obtained in the same manner as in Production Example 1 and 250 g of n-hexane (relative dielectric constant: 1.89) were added to a table type kneader (PNV-1 manufactured by Irie Trading Co., Ltd.). Type) was mixed and stirred to obtain a granulated product of a crosslinked carboxyl group-containing polymer. The obtained granulated product is subjected to wet extrusion using a twin dome gran test machine (manufactured by Fuji Paudal Co., Ltd., model MG-55, dome die opening 1.0 mm, opening degree 35.4%) to obtain particles. The diameter was adjusted. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 98 g of a granular crosslinked carboxyl group-containing polymer. However, most of the obtained granular cross-linked carboxyl group-containing polymer collapsed and did not maintain a granular shape.

  The above items were evaluated for the obtained granular crosslinked carboxyl group-containing polymer. The results are shown in Table 1.

[Comparative Example 2]
100 g of a crosslinked carboxyl group-containing polymer obtained by the same method as in Production Example 1 and 150 g of acetone (relative dielectric constant: 20.7) were added to a table type kneader (Irie Trading Co., Ltd., PNV-1 type). Were mixed and stirred to obtain a mass of a crosslinked carboxyl group-containing polymer. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 85 g of an agglomerated crosslinked carboxyl group-containing polymer.

  The above items were evaluated for the obtained bulk crosslinked carboxyl group-containing polymer. The results are shown in Table 1.

[Comparative Example 3]
100 g of a crosslinked carboxyl group-containing polymer obtained in the same manner as in Production Example 1 and 100 g of methanol (relative dielectric constant: 33.1) were added to a table type kneader (Irie Trading Co., Ltd., PNV-1 type). Were mixed and stirred to obtain a mass of a crosslinked carboxyl group-containing polymer. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 85 g of an agglomerated crosslinked carboxyl group-containing polymer.

  The above items were evaluated for the obtained bulk crosslinked carboxyl group-containing polymer. The results are shown in Table 1.

[Reference Example 1]
The above items were evaluated for the crosslinked carboxyl group-containing polymer obtained by the same method as in Production Example 1. However, the median particle size was measured with a laser diffraction particle size distribution analyzer (model: SALD-2000J, manufactured by Shimadzu Corporation, dispersion medium: normal hexane). The results are shown in Table 1.

  From the results in Table 1, the granular cross-linked carboxyl group-containing polymer obtained by the production method of the present invention has a specific medium particle size, a large bulk density, hardly collapse after aggregation, and for a short time. It can be seen that it swells in water.

  According to the production method of the present invention, compared to a finely powdered carboxyl group-containing polymer, macho is less likely to occur, is less likely to collapse after aggregation, is excellent in water swellability, has less dustiness, and is excellent in workability. A granular carboxyl group-containing polymer can be obtained. In addition, after dissolving the granular carboxyl group-containing polymer obtained by the production method of the present invention in water, by neutralizing with an alkali such as sodium hydroxide or triethanolamine, the smoothness of the surface in a short time, A neutralized viscous liquid having excellent thickening and transparency can be obtained.

Claims (5)

  A method for producing a granular carboxyl group-containing polymer, comprising mixing and stirring a carboxyl group-containing polymer and an organic solvent having a relative dielectric constant of 1.9 to 20, followed by granulation.   The carboxyl group-containing polymer is a carboxyl group-containing polymer obtained by polymerizing a monomer component having an α, β-unsaturated carboxylic acid as a main constituent monomer in an inert solvent. The manufacturing method of the granular carboxyl group containing polymer as described in any one of.   The manufacturing method of the granular carboxyl group containing polymer of Claim 1 or 2 whose usage-amount of an organic solvent is 150-400 mass parts with respect to 100 mass parts of carboxyl group containing polymers.   A particle size is adjusted by a granulator after mixing and stirring and granulating a carboxyl group-containing polymer and an organic solvent having a relative dielectric constant of 1.9-20. The manufacturing method of the granular carboxyl group containing polymer of any one of these. A granular carboxyl group-containing polymer obtained by the production method according to any one of claims 1 to 4,
1) The median particle size is 200 to 800 μm,
2) Bulk density is 0.20 g / ml or more,
3) After putting the granular carboxyl group-containing polymer into the water at 25 ° C. which is allowed to stand so as to be 0.5% by mass with respect to water, all the granular carboxyl group-containing polymer swells. Takes less than 30 minutes,
A granular carboxyl group-containing polymer characterized by having the following characteristics: