JP2012007010A - Method of manufacturing granular carboxyl group-containing polymer particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a granular carboxyl group-containing polymer particle which is excellent in the dispersibility to water, exhibits low dusting and high fluidity, and has only a small remaining solvent amount; and to provide a granular carboxyl group-containing polymer particle obtained by the manufacturing method.SOLUTION: The method of manufacturing a granular carboxyl group-containing polymer particle comprises the steps of: polymerizing a monomer containing (meth)acrylic acid as a main component to fabricate a carboxyl group-containing polymer; adding at least one compound selected from the group consisting of polyhydric alcohol fatty acid esters and polyhydric alcohol fatty acid ester alkylene oxide adducts to the carboxyl group-containing polymer to fabricate a mixture; moistening the mixture so that the moisture content of the mixture becomes 3 to 20 mass% to fabricate an aggregate of the mixture; and drying and then crushing the aggregate of the mixture. In the step of fabricating the mixture, the use amount of the at least one compound selected from the group consisting of polyhydric alcohol fatty acid esters and polyhydric alcohol fatty acid ester alkylene oxide adducts is 0.2 to 5 pts.mass with respect to 100 pts.mass of the (meth)acrylic acid.

Description

The present invention relates to a method for producing granular carboxyl group-containing polymer particles, and a granular carboxyl group-containing polymer particle obtained by the method for producing granular carboxyl group-containing polymer particles.

Carboxy group-containing polymers are used as thickeners for cosmetics, moisturizers such as poultices, suspension stabilizers such as emulsifiers and suspensions, gelling bases for batteries and the like.

When the carboxyl group-containing polymer is used for the above-mentioned purposes, for example, the carboxyl group-containing polymer is added to water or the like to prepare a uniform dispersion, neutralized with an alkali, dissolved and used. However, in general, since the carboxyl group-containing polymer is a fine powder, a lump (maco) is likely to occur when dispersed in water or the like. Once Mamako is formed, a gel-like layer is formed on the surface of Mamako, so that the speed at which water penetrates into Mamako is slow, and it is difficult to obtain a uniform dispersion.

From the viewpoint of preventing the formation of mamako, for example, when a carboxyl group-containing polymer is produced by polymerizing α, β-unsaturated carboxylic acid or the like, a polyhydric alcohol fatty acid ester and a polyhydric alcohol fatty acid ester alkylene oxide adduct By adding a specific amount of at least one of these compounds and polymerizing them, the carboxyl group has excellent solubility in water and is excellent in thickening of the neutralized viscous liquid obtained after neutralizing the aqueous solution with alkali. It is known that a containing polymer is obtained (see Patent Document 1).

In addition, since the carboxyl group-containing polymer is a fine powder and easily charged, the powder is severely powdered during handling (high dusting property) and inferior in fluidity. From the standpoint of preventing dusting, for example, a method is known in which a carboxyl group-containing polymer obtained by polymerization is humidified and aggregated, and the resulting aggregate is dried and then granulated by pulverization ( Patent Document 2).

JP 2000-355614 A International Publication No. 07/132673 pamphlet

However, the carboxyl group-containing polymer composition disclosed in Patent Document 1 is excellent in solubility in water or the like, but there is room for improvement in, for example, dispersibility under non-stirring conditions. In addition, when the carboxyl group-containing polymer is humidified and aggregated as in the method disclosed in Patent Document 2, depending on the water content of the carboxyl group-containing polymer, the resulting aggregate becomes a hard lump and is difficult to grind. In addition, the dispersibility of granular particles obtained by drying and then pulverizing the aggregate in water or the like may decrease.

Furthermore, although the carboxyl group-containing polymer has a problem that the amount of residual solvent derived from the production process is large, conventionally, studies for reducing the amount of residual solvent have not been sufficiently performed.

An object of this invention is to provide the manufacturing method of the granular carboxyl group containing polymer particle which is excellent in the dispersibility to water, is low dust generation, is highly fluid, and has little residual solvent amount. Another object of the present invention is to provide granular carboxyl group-containing polymer particles obtained by the method for producing the granular carboxyl group-containing polymer particles.

The present invention includes a step of polymerizing a monomer having (meth) acrylic acid as a main component to prepare a carboxyl group-containing polymer, and a polyhydric alcohol fatty acid ester and a polyhydric alcohol fatty acid ester. Adding at least one compound selected from the group consisting of an alkylene oxide adduct and preparing a mixture; and humidifying the mixture to a moisture content of 3 to 20% by mass; A step of producing an aggregate, and a step of drying and then pulverizing the aggregate of the mixture. In the step of producing the mixture, the polyhydric alcohol fatty acid ester and the polyhydric alcohol fatty acid ester alkylene oxide adduct The amount of at least one compound selected from the group consisting of: (mass) acrylic acid 100 parts by mass In contrast, a method for producing granular carboxyl group-containing polymer particles is 0.2 to 5 parts by weight.
The present invention is described in detail below.

The present inventors have found that the residual solvent amount derived from the production process is reduced by humidifying and aggregating the carboxyl group-containing polymer. The amount of decrease in the residual solvent increases as the moisture content of the carboxyl group-containing polymer by humidification increases. However, simply moistening and aggregating the carboxyl group-containing polymer, if the water content of the carboxyl group-containing polymer is too high, the resulting aggregate becomes a hard mass and difficult to grind, After the aggregate is dried, the dispersibility of the granular particles obtained by pulverization in water or the like decreases.

In response to this problem, the inventors polymerized a monomer mainly composed of (meth) acrylic acid to prepare a carboxyl group-containing polymer, and the carboxyl group-containing polymer was mixed with a polyhydric alcohol fatty acid. A step of adding a specific amount of at least one compound selected from the group consisting of an ester and a polyhydric alcohol fatty acid ester alkylene oxide adduct to produce a mixture, and humidifying the mixture to a specific moisture content; In addition, according to the method including the step of producing the aggregate of the mixture and the step of pulverizing the aggregate of the mixture after drying, the dispersibility in water and the like is excellent and the amount of residual solvent is small. It has been found that granular carboxyl group-containing polymer particles can be obtained.
Furthermore, the present inventors show that the granular carboxyl group-containing polymer particles obtained by the above method have a high fluidity during handling, and are even more prominent than when the carboxyl group-containing polymer is simply humidified and aggregated. It was found that the dust generation property is suppressed, and the present invention has been completed.

In the method for producing granular carboxyl group-containing polymer particles of the present invention, first, a step of polymerizing a monomer mainly composed of (meth) acrylic acid to produce a carboxyl group-containing polymer is performed.
In the present specification, (meth) acryl means both acrylic and methacrylic.
In the step of preparing the carboxyl group-containing polymer, the dispersibility of the obtained granular carboxyl group-containing polymer particles in water or the like is improved, so that 100 parts by mass of (meth) acrylic acid and the carbon number of the alkyl group are A carboxyl group-containing polymer is prepared by polymerizing 18 to 24 (meth) acrylic acid alkyl ester 1 to 10 parts by mass and 0.01 to 1 part by mass of a compound having two or more ethylenically unsaturated groups. It is preferable to do.

The (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group refers to an ester of (meth) acrylic acid and a higher alcohol having 18 to 24 carbon atoms in the alkyl group.
Examples of the (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group include, for example, an ester of (meth) acrylic acid and stearyl alcohol, an ester of (meth) acrylic acid and eicosanol, and (meth) acrylic. Examples include esters of acid and behenyl alcohol, and esters of (meth) acrylic acid and tetracosanol. Among these (meth) acrylic acid alkyl esters having 18 to 24 carbon atoms in these alkyl groups, the neutralized viscous liquid prepared using the obtained granular carboxyl group-containing polymer particles and the liquid in the presence of an electrolyte From the viewpoint of excellent viscosity characteristics or texture, stearyl methacrylate, eicosanyl methacrylate, behenyl methacrylate and tetracosanyl methacrylate are preferably used. These (meth) acrylic acid alkyl esters having 18 to 24 carbon atoms in these alkyl groups may be used alone or in combination of two or more.

In the present specification, the neutralized viscous liquid refers to about pH 7 (pH = 6 to 8) using a neutralizing agent such as an alkaline compound after dispersing granular carboxyl group-containing polymer particles and the like in water. The solution prepared in

As a (meth) acrylic-acid alkylester whose carbon number of the said alkyl group is 18-24, you may use commercial items, such as brand name Blemmer VMA70 by NOF Corporation.

The amount of alkyl (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group is preferably 1 to 10 parts by mass, more preferably 1 to 100 parts by mass of (meth) acrylic acid. .5 to 8 parts by mass. When the amount of alkyl (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group is less than 1 part by mass, when the resulting granular carboxyl group-containing polymer particles are dispersed in water, mamako is generated. May be easier. When the amount of alkyl (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group exceeds 10 parts by mass, a neutralized viscous liquid is prepared using the resulting granular carboxyl group-containing polymer particles. At this time, the solubility of the granular carboxyl group-containing polymer particles may be deteriorated.

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 include divinyl acid, vinyl crotonate, 1,5-hexadiene, divinylbenzene, and the like. Among these compounds having two or more ethylenically unsaturated groups, when preparing a neutralized viscous liquid using the obtained granular carboxyl group-containing polymer particles, high viscosity can be imparted with a small amount of use, Moreover, when preparing an emulsion, suspension, etc., since a high suspension stability can be provided, pentaerythritol allyl ether, tetraallyloxyethane, triallyl phosphate, and polyallyl saccharose are used suitably. These compounds having two or more ethylenically unsaturated groups may be used alone or in combination of two or more.

The amount of the compound having two or more ethylenically unsaturated groups to be used is preferably 0.01 to 1 part by mass, more preferably 0.3 to 0.00 with respect to 100 parts by mass of (meth) acrylic acid. 8 parts by mass. When the amount of the compound having two or more ethylenically unsaturated groups is less than 0.01 parts by mass, when preparing the neutralized viscous liquid using the obtained granular carboxyl group-containing polymer particles, Viscosity may be reduced. When the amount of the compound having two or more ethylenically unsaturated groups exceeds 1 part by mass, an insoluble gel is formed when preparing a neutralized viscous liquid using the resulting granular carboxyl group-containing polymer particles It may be easy to do.

In the method for producing granular carboxyl group-containing polymer particles of the present invention, a method for polymerizing a monomer mainly composed of (meth) acrylic acid is not particularly limited, and examples thereof include (meth) acrylic acid and the alkyl group. A polymerization solvent that dissolves a monomer such as a (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms and a compound having two or more ethylenically unsaturated groups, and does not dissolve the resulting carboxyl group-containing polymer Among them, a method of polymerizing may be mentioned, and more specifically, for example, (meth) acrylic acid, (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms and ethylenically unsaturated group And a method of polymerizing a monomer such as a compound having 2 or more in the polymerization solvent in the presence of a radical polymerization initiator.

The radical polymerization initiator is not particularly limited, and for example, α, α′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobismethyl. Examples include isobutyrate, benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, and tertiary butyl hydroperoxide. These radical polymerization initiators may be used alone or in combination of two or more.

The amount of the 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 (meth) acrylic acid. More preferred. When the amount of the radical polymerization initiator used is less than 0.01 parts by mass, the polymerization reaction rate becomes slow, which may not be economical. When the usage-amount of a radical polymerization initiator exceeds 0.45 mass part, there exists a possibility that a polymerization reaction rate may become quick and control of reaction may become difficult.

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

As the usage-amount of the said polymerization solvent, it is preferable that it is 200-10000 mass parts with respect to 100 mass parts of (meth) acrylic acid, and it is more preferable that it is 300-2000 mass parts. When the amount of the polymerization solvent used is less than 200 parts by mass, the carboxyl group-containing polymer precipitates as the polymerization reaction proceeds, and it becomes difficult to uniformly stir, making it difficult to control the reaction. When the amount of the polymerization solvent used exceeds 10,000 parts by mass, the production amount of the carboxyl group-containing polymer per unit weight is small, which may not be economical.

In the method for producing granular carboxyl group-containing polymer particles of the present invention, the atmosphere when polymerizing the monomer mainly composed of (meth) acrylic acid is, for example, an inert gas atmosphere such as nitrogen gas or argon gas. It is preferable.
The reaction temperature is preferably 50 to 90 ° C. in order to suppress the increase in the viscosity of the reaction solution to facilitate reaction control or to control the bulk density of the resulting carboxyl group-containing polymer. It is more preferable that it is 55-75 degreeC. Since the reaction time varies depending on the reaction temperature, it cannot be generally determined, but is usually 2 to 10 hours.

In addition, after completion | finish of reaction, the said carboxyl group containing polymer of white fine powder can be isolated by heating a reaction solution to 80-130 degreeC, and removing the said polymerization solvent.

In the method for producing granular carboxyl group-containing polymer particles of the present invention, at least one selected from the group consisting of a polyhydric alcohol fatty acid ester and a polyhydric alcohol fatty acid ester alkylene oxide adduct is then added to the carboxyl group-containing polymer. A step of making a mixture is performed by adding seed compounds.

In the method for producing granular carboxyl group-containing polymer particles of the present invention, by performing the step of preparing the mixture, granular carboxyl having excellent dispersibility in water and the like even under non-stirring conditions and having low dusting properties. Group-containing polymer particles can be obtained. This is because the surface of the carboxyl group-containing polymer is coated with the compound by the addition of the compound, so that the dispersibility of the carboxyl group-containing polymer in water or the like is improved, and the antistatic effect generates dust. This is thought to be due to a decrease in performance. The effects such as improvement in dispersibility and reduction in dusting properties can be obtained by adding the compound after preparing the carboxyl group-containing polymer, and adding the compound during polymerization to the carboxyl group-containing polymer. Larger than when the compound is incorporated. By granulating in the process mentioned later, the dusting property of the obtained granular carboxyl group containing polymer particle further falls.
In addition, the surface of the carboxyl group-containing polymer is coated with the compound, so that the agglomeration strength of the carboxyl group-containing polymer in the step of preparing the aggregate described later is slightly weakened, and after the aggregate is dried When pulverizing, large particles having a particle diameter of 850 μm or more are hardly generated. Therefore, the obtained granular carboxyl group-containing polymer particles have a median particle size of around 200 μm, and are excellent in dispersibility and solubility in water or the like.

The polyhydric alcohol in the polyhydric alcohol fatty acid ester is not particularly limited, and examples thereof include glycerin, polyglycerin, trimethylolpropane, pentaerythritol, sorbit, sorbitan and the like. The fatty acid in the polyhydric alcohol fatty acid ester is not particularly limited. For example, stearic acid, isostearic acid, distearic acid, diisostearic acid, tristearic acid, triisostearic acid, tetraisostearic acid, oleic acid, dioleic acid, triolein An acid, pentaoleic acid, dekaoleic acid, etc. are mentioned.

Typical examples of the polyhydric alcohol fatty acid ester include esters of glycerin or polyglycerin and a fatty acid having 10 to 30 carbon atoms. Among these polyhydric alcohol fatty acid esters, esters of glycerin or polyglycerin with stearic acid, isostearic acid or oleic acid are preferred.

Specific examples of the ester of glycerin or polyglycerin and stearic acid include glyceryl stearate, glyceryl distearate, glyceryl tristearate, diglyceryl stearate, tetraglyceryl stearate, tetraglyceryl tristearate, pentastearic acid Tetraglyceryl, hexaglyceryl stearate, hexaglyceryl tristearate, hexaglyceryl pentastearate, decaglyceryl stearate, decaglyceryl distearate, decaglyceryl tristearate, decaglyceryl pentastearate, decaglyceryl heptearate, decastearate Examples include acid decaglyceryl.

Specific examples of the ester of glycerin or polyglycerin and isostearic acid include glyceryl isostearate, diglyceryl isostearate, decaglyceryl isostearate, decaglyceryl diisostearate, decaglyceryl triisostearate, decaglyceryl pentaisostearate, hepta Examples include decaglyceryl isostearate and decaglyceryl decaisostearate.

Specific examples of the ester of glycerin or polyglycerin and oleic acid include glyceryl oleate, glyceryl dioleate, glyceryl trioleate, diglyceryl oleate, diglyceryl dioleate, tetraglyceryl oleate, tetraoleate pentaoleate Examples include glyceryl, hexaglyceryl oleate, hexaglyceryl pentaoleate, decaglyceryl oleate, decaglyceryl dioleate, decaglyceryl trioleate, decaglyceryl pentaoleate, decaglyceryl heptaoleate, decaglyceryl decaoleate, and the like.

Among these polyhydric alcohol fatty acid esters, the obtained granular carboxyl group-containing polymer particles have excellent dispersibility in water, etc. even under non-stirring conditions, low dust generation during handling, and good fluidity Therefore, decaglyceryl dekaleate, decaglyceryl pentaoleate, decaglyceryl diisostearate, decaglyceryl oleate, hexaglyceryl oleate, tetraglyceryl stearate, diglyceryl oleate and glyceryl trioleate are preferably used. .

Examples of the polyhydric alcohol fatty acid ester alkylene oxide adduct include an alkylene oxide adduct of the polyhydric alcohol fatty acid ester.
The polyhydric alcohol in the polyhydric alcohol fatty acid ester alkylene oxide adduct is not particularly limited, and examples thereof include glycerin, polyglycerin, sorbit, sorbitan and the like. The fatty acid in the polyhydric alcohol fatty acid ester alkylene oxide adduct is not particularly limited, and examples thereof include stearic acid, isostearic acid, and oleic acid.
Examples of the polyhydric alcohol fatty acid ester in the polyhydric alcohol fatty acid ester alkylene oxide adduct include castor oil and castor oil derivatives.

Examples of the oxyalkylene chain in the polyhydric alcohol fatty acid ester alkylene oxide adduct include the following formula:
^{_{- (CH 2 -CHR 1 -O)}} n -
(Wherein, R ¹ represents a hydrogen atom, a methyl group or an ethyl group. N represents an integer of 1 to 100, preferably an integer of 5 to 60).

Typical examples of the polyhydric alcohol fatty acid ester alkylene oxide adduct include polyoxyethylene sorbite fatty acid ester, polyoxyethylene castor oil derivative, polyoxyethylene hydrogenated castor oil derivative, polyoxyethylene glycerin fatty acid ester and the like.

Specific examples of the polyoxyethylene sorbite fatty acid ester include tetraoleic acid polyoxyethylene sorbite, pentaoleic acid polyoxyethylene sorbite, isostearic acid polyoxyethylene sorbite, hexastearic acid polyoxyethylene sorbite, and the like.

Specific examples of the polyoxyethylene castor oil derivative or the polyoxyethylene hydrogenated castor oil derivative include polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene hydrogenated castor oil laurate, polyoxyethylene hydrogenated isostearate Castor oil, polyoxyethylene hydrogenated castor oil triisostearate and the like.

Specific examples of the polyoxyethylene glycerin fatty acid ester include polyoxyethylene glyceryl monostearate, polyoxyethylene glyceryl distearate, polyoxyethylene glyceryl tristearate, polyoxyethylene glyceryl oleate, polyoxyethylene glyceryl dioleate, Examples thereof include polyoxyethylene glyceryl trioleate, polyoxyethylene glyceryl isostearate, polyoxyethylene glyceryl diisostearate, polyoxyethylene glyceryl triisostearate and the like.

Among these polyhydric alcohol fatty acid ester alkylene oxide adducts, the obtained granular carboxyl group-containing polymer particles are excellent in dispersibility in water and the like even under non-stirring conditions, and have low dust generation during handling, Because of its good fluidity, polyoxyethylene hydrogenated castor oil, polyoxyethylene castor oil, isostearic acid polyoxyethylene hydrogenated castor oil, polyisoethylene stearate polyoxyethylene hydrogenated castor oil, and polyoxyethylene sorbite tetraoleate are suitable. Used for.

These polyhydric alcohol fatty acid esters and polyhydric alcohol fatty acid ester alkylene oxide adducts may be used alone or in combination of two or more.

The total amount of at least one compound selected from the group consisting of the polyhydric alcohol fatty acid ester and the polyhydric alcohol fatty acid ester alkylene oxide adduct is the (meth) acrylic acid constituting the carboxyl group-containing polymer. It is 0.2-5 mass parts with respect to 100 mass parts, Preferably it is 0.5-4 mass parts. When the amount of the compound used is less than 0.2 parts by mass, when the obtained granular carboxyl group-containing polymer particles are dispersed in water, mamako is likely to be generated or the dissolution rate is likely to be slow, and it can be obtained. The dust generation property of the granular carboxyl group-containing polymer particles is increased. When the amount of the compound used exceeds 5 parts by mass, when preparing a neutralized viscous liquid using the resulting granular carboxyl group-containing polymer particles, the viscosity of the liquid increases, and the permeation of the liquid The rate gets worse.

In the method for producing granular carboxyl group-containing polymer particles of the present invention, a specific method of adding at least one compound selected from the group consisting of the polyhydric alcohol fatty acid ester and the polyhydric alcohol fatty acid ester alkylene oxide adduct Examples of the method include a method of adding the compound when isolating the carboxyl group-containing polymer; a method of adding the compound after isolating the carboxyl group-containing polymer, and the like. Among these methods, since the treatment is simple, a method of adding the compound after isolating the carboxyl group-containing polymer is preferably used.

The addition of at least one compound selected from the group consisting of the polyhydric alcohol fatty acid ester and the polyhydric alcohol fatty acid ester alkylene oxide adduct is performed in order to uniformly mix the carboxyl group-containing polymer and the compound. It is preferable to carry out in the presence of a solvent. Examples of the solvent include ethyl acetate, cyclohexane, normal heptane and the like. Among these solvents, ethyl acetate and normal heptane are preferably used from the viewpoint of safety and the like. These solvents may be used alone or in combination of two or more.
The amount of the solvent to be used is not particularly limited, but since the carboxyl group-containing polymer and the compound are uniformly mixed, and the solvent can be easily removed after the preparation of the mixture, the amount of the solvent is 100 parts by mass. 10 to 50 parts by mass, and more preferably 20 to 40 parts by mass.

In addition, as an apparatus used when adding at least one compound selected from the group consisting of the polyhydric alcohol fatty acid ester and the polyhydric alcohol fatty acid ester alkylene oxide adduct, the carboxyl group-containing polymer is isolated. In the case of adding the compound in the process, for example, an apparatus used for a polymerization reaction, an apparatus for removing the polymerization solvent, etc. may be mentioned, and the compound is added after the carboxyl group-containing polymer is isolated. For example, a general mixer used for mixing such as a blender, a kneader, a Henschel mixer, and a conical mixer can be used.

After producing the mixture as described above, the mixture may be dried as necessary. The drying device used for drying the mixture is not particularly limited, but a vacuum dryer is preferably used in order to avoid adverse effects on the physical properties of the mixture and to increase the drying efficiency.
Moreover, as drying temperature at the time of drying the said mixture, it is preferable that it is 30-130 degreeC, and it is more preferable that it is 50-120 degreeC. When the drying temperature is less than 30 ° C., it takes a long time to dry, and there is a possibility that it is not economical. When the drying temperature exceeds 130 ° C., the dispersibility of the obtained granular carboxyl group-containing polymer particles in water or the like may be deteriorated.

In the method for producing granular carboxyl group-containing polymer particles of the present invention, the step of humidifying the mixture so that the water content becomes 3 to 20% by mass to produce an aggregate of the mixture is then performed. By humidifying the mixture so that the water content becomes 3 to 20% by mass, fine powders in the mixture are combined with water as a binder to form an aggregate.

In the method for producing granular carboxyl group-containing polymer particles of the present invention, granular carboxyl group-containing polymer particles with a small amount of residual solvent can be obtained by performing a step of producing an aggregate of the mixture. This is because the affinity of the carboxyl group-containing polymer with respect to water is greater than the affinity with respect to the residual solvent, so that water enters the inside of the carboxyl group-containing polymer by humidification of the mixture, and water and the residual solvent are exchanged. This is probably because the residual solvent is ejected.
In the present specification, the residual solvent means a solvent that is used in a production process such as a process of producing the carboxyl group-containing polymer and is left in the carboxyl group-containing polymer. Such residual solvent is difficult to reduce by a normal drying method.

In the method for producing granular carboxyl group-containing polymer particles of the present invention, the moisture content of the mixture by humidification is 3 to 20% by mass, and preferably 4 to 15% by mass. When the water content is less than 3% by mass, sufficient agglomeration of the mixture cannot be obtained, and the residual solvent amount of the obtained granular carboxyl group-containing polymer particles is not sufficiently reduced. When the water content exceeds 20% by mass, aggregation of the mixture is promoted too much, so that the resulting aggregate becomes difficult to grind after drying. For example, the obtained granular carboxyl group-containing polymer particles are mixed with water. Such a problem that the dissolution rate slows down when dispersed in the same.

Moreover, in the manufacturing method of the granular carboxyl group-containing polymer particle of this invention, the amount of reduction | decrease of the residual solvent in the obtained granular carboxyl group-containing polymer particle becomes large, so that the moisture content of the said mixture by humidification is high. For example, when the amount of residual solvent in the mixture before humidification is 8000 ppm of normal heptane and 100 ppm of ethyl acetate, for example, if the moisture content of the mixture by humidification is 3 to 6% by mass, The residual solvent amount of the coalesced particles is about 2000 to 5000 ppm. Similarly, if the water content is 7 to 10% by mass, the residual solvent amount is about 100 to 2000 ppm, and if the water content is 11 to 15% by mass, the residual solvent The amount is about 30 to 100 ppm, and if the water content is 15 to 20% by mass, the residual solvent amount is about 30 ppm or less.
Furthermore, the residual solvent reduction efficiency due to humidification varies depending on the type of the residual solvent, and examples of the residual solvent with high reduction efficiency include ethyl acetate, normal heptane, and cyclohexane.

In the present specification, the moisture content refers to the ratio between the mass reduced by drying the aggregate of the mixture and the mass before drying. More specifically, for example, when 2 g of the aggregate of the mixture is heat-dried at 105 ° C. for 3 hours, the water content (% by mass) is calculated by the following formula.
Water content (% by mass) = [(2-X) / 2] × 100
(In the formula, X is mass (g) after heat drying)

In the method for producing granular carboxyl group-containing polymer particles of the present invention, the method of humidifying the mixture so that the water content is 3 to 20% by mass is not particularly limited, and for example, the mixture may be a flask or the like. Examples include a method of absorbing moisture in an airtight container; a method of placing the mixture on a continuously moving belt and allowing the mixture to pass through a humidifying tank. Among these methods, since the productivity is good and the operation is simple, a method in which the mixture is placed on a continuously moving belt and passed through a humidifying tank is preferably used.

In the present specification, as an example of a method for humidifying the mixture so that the moisture content is 3 to 20% by mass, the mixture is placed on a continuously moving belt and passed through a humidifying tank. This will be specifically described below.

When the mixture is placed on a continuously moving belt such as a granulating apparatus, the thickness of the mixture is preferably 5 to 30 mm, and more preferably 10 to 25 mm. If the thickness is less than 5 mm, the resulting aggregate of the mixture may be difficult to peel from the belt. When the thickness exceeds 30 mm, the moisture content varies between the upper part and the lower part of the obtained aggregate of the mixture on the belt, and there is a possibility that homogeneous granular carboxyl group-containing polymer particles cannot be obtained.

The temperature in the humidification tank is preferably 50 to 100 ° C, and more preferably 60 to 100 ° C. When the temperature in the humidification tank is less than 50 ° C., it may take a long time to aggregate the mixture. When the temperature in the humidification tank exceeds 100 ° C., a large amount of energy is required to maintain the temperature, which may be not economical.

The relative humidity in the humidification tank is preferably 70 to 100%, and more preferably 75 to 100%. When the relative humidity in the humidifying tank is less than 70%, it may take a long time to aggregate the mixture. When the relative humidity in the humidification tank exceeds 100%, condensed water is generated, the mixture swells with the water, and the resulting granular carboxyl group-containing polymer particles may have low solubility in water or the like. There is.

The time for the mixture to pass through the humidification tank is preferably 2 to 15 minutes, and more preferably 3 to 12 minutes. When the passage time is less than 2 minutes, the aggregate strength of the aggregate of the resulting mixture becomes weak, the amount of fine powder increases after pulverization of the aggregate, and the particle-like carboxyl group-containing polymer particles obtained have a dust generation property. There is a risk that it may increase or fluidity may decrease. When the passage time exceeds 15 minutes, the aggregation strength of the aggregate of the resulting mixture becomes strong, and the solubility of the resulting granular carboxyl group-containing polymer particles may be lowered.

In the method for producing granular carboxyl group-containing polymer particles of the present invention, the aggregate of the mixture is then dried and then pulverized. The aggregate of the mixture is dried and then pulverized to obtain granular carboxyl group-containing polymer particles.

In the method for producing granular carboxyl group-containing polymer particles of the present invention, the carboxyl group-containing polymer is obtained by performing the step of producing the aggregate and the step of drying and then pulverizing the aggregate of the mixture. Since the carboxyl group-containing polymer is a fine powder and is easily charged, the high dusting property and low fluidity can be improved.

Although the drying apparatus used when drying the aggregate of the said mixture is not specifically limited, For example, a ventilation dryer, a groove type dryer, a reduced pressure dryer etc. are mentioned. The drying temperature for drying the aggregate of the mixture is preferably 80 to 130 ° C, more preferably 90 to 120 ° C. When the drying temperature is less than 80 ° C., drying may take a long time. When the drying temperature exceeds 130 ° C, the solubility of the obtained granular carboxyl group-containing polymer particles in water or the like may be lowered.
In addition, the moisture content of the aggregate of the mixture after drying ensures fluidity at the time of pulverization, and in order to prevent agglomeration even when the obtained granular carboxyl group-containing polymer particles are stored for a long period of time, It is preferable to make it 19% by mass or less.

An apparatus used for pulverizing the aggregate of the mixture after drying is not particularly limited. For example, a commonly used pulverizer such as a pin mill type pulverizer, a hammer mill type pulverizer, or a jet mill type pulverizer may be used. Can be used.

The granular carboxyl group-containing polymer particles obtained as described above can be classified to a desired intermediate particle size by further classifying them using a sieve having a desired opening and removing coarse powder.

The granular carboxyl group-containing polymer particles obtained by the production method of the present invention are excellent in dispersibility in water and the like, have low dust generation and high fluidity, and have a small amount of residual solvent. It can use suitably for the use of. The granular carboxyl group-containing polymer particles obtained by the production method of the present invention and having the following characteristics 1) to 4) are also one aspect of the present invention.
1) Residual solvent amount is 5000 ppm or less 2) Median particle size is 75 to 240 μm
3) Dust generation degree is 100 cpm or less 4) Bulk density is 0.35 g / cm ³ or more

The granular carboxyl group-containing polymer particles of the present invention have a residual solvent amount of 5000 ppm or less, preferably 4000 ppm or less. When the residual solvent amount exceeds 5000 ppm, it is not preferable from the viewpoint of safety and health and the environment.

The granular carboxyl group-containing polymer particles of the present invention have a median particle diameter of 75 to 240 μm, preferably 100 to 200 μm. When the median particle diameter is less than 75 μm, when the granular carboxyl group-containing polymer particles are dispersed in water, mako is likely to occur, and the granular carboxyl group-containing polymer particles have high dust generation properties. . When the median particle diameter exceeds 240 μm, the dispersibility of the granular carboxyl group-containing polymer particles in water or the like is deteriorated.

The granular carboxyl group-containing polymer particles of the present invention have a dust generation degree of 100 cpm or less, preferably 80 cpm or less. When the degree of dust generation exceeds 100 cpm, the granular carboxyl group-containing polymer particles are severely powdered during handling, which is a problem in terms of work and safety and health.
In addition, in this specification, a dust generation degree means the dust generation degree measured using the dust meter (digital indicator P-5 type) by Shibata Rika Chemical Co., for example. A detailed method for measuring the degree of dust generation will be described in the evaluation method described later.

Granular carboxyl group-containing polymer particles of the present invention is a bulk density of 0.35 g / cm ³ or more, preferably 0.35~0.6g / cm ^3. When the bulk density is less than 0.35 g / cm ³ , the amount of fine powder is large, and when the granular carboxyl group-containing polymer particles are dispersed in water, mako is likely to occur, and the granular carboxyl group-containing polymer Increases particle generation.

The granular carboxyl group-containing polymer particles of the present invention are poured into undisturbed water at 25 ° C. in a standing state at a stretch so as to be 0.5 mass% with respect to water, and the dispersed state of the particles is changed. When observed visually, the time required for all of the particles to disperse without producing mamaco is preferably 30 minutes or less, and more preferably 15 minutes or less. When it takes more than 30 minutes to disperse all of the granular carboxyl group-containing polymer particles without forming mamaco, the particles are sufficiently dispersible compared to the conventional carboxyl group-containing polymer. That is not preferable. The detailed measurement method will be described in the evaluation method described later.

While stirring the granular carboxyl group-containing polymer particles of the present invention at a rotational speed of 500 rpm using a magnetic stirrer, the mixture was poured into water at 25 ° C. at a stretch so as to be 0.5 mass% with respect to water. When the dispersion state of the particles is visually observed, the time that the white of the powder of the particles disappears at the bottom of the spiral is preferably 5 minutes or less, more preferably 3 minutes or less, and more preferably 2 minutes or less. More preferably. When the time when the white of the powder of the particles disappears at the bottom of the vortex exceeds 5 minutes, it cannot be said that the particles are sufficiently dispersible as compared with the conventional carboxyl group-containing polymer, which is not preferable. The detailed measurement method will be described in the evaluation method described later.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the granular carboxyl group containing polymer particle which is excellent in the dispersibility to water, is low dust generation, is highly fluid, and has little residual solvent amount can be provided. Moreover, according to this invention, the granular carboxyl group containing polymer particle obtained by the manufacturing method of this granular carboxyl group containing polymer particle can be provided.

Although the manufacture example, an Example, and a comparative example are given to the following and the aspect of this invention is demonstrated concretely, this invention is not limited to these Examples.

[Evaluation methods]
(1) Moisture content 2g of a carboxyl group-containing polymer or 2g of a mixture of carboxyl group-containing polymers is dried by heating at 105 ° C for 3 hours, and the moisture content (% by mass) is calculated by the following formula. Ask.
Water content (% by mass) = [(2-X) / 2] × 100
In formula, X represents the mass (g) after heat drying.

(2) 10 g of bulk density carboxyl group-containing polymer or granular carboxyl group-containing polymer particles are put into a 50 cm ³ volume empty graduated cylinder within 20 seconds from the height of the upper 5 cm, and the polymer or particles occupy The volume (cm ³ ) is measured. The bulk density (g / cm ³ ) is calculated and determined by dividing the mass of the polymer or particle by 10 g by volume (cm ³ ).

(3) Median particle diameter In this specification, the median particle diameter is a polymer or particle remaining on each sieve when the carboxyl group-containing polymer or granular carboxyl group-containing polymer particles are classified with a sieve. The particle diameter corresponding to the sieve opening when the integrated mass obtained by sequentially integrating the masses of the polymers or particles reaches 50% by mass of the total mass of the polymer or 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 saucer are prepared. Laminate large sieves sequentially. 100 g of carboxyl group-containing polymer or granular carboxyl group-containing polymer particles are put into a sieve having the largest opening, and are vibrated for 10 minutes using a low-tap sieve vibrator. Particles corresponding to sieve openings when polymer or particles remaining on each sieve are weighed and sequentially laminated to reach 50% by mass of the total mass of the polymer or particles The particle diameter obtained by calculating the diameter according to the following formula is defined as the median particle diameter.
Median particle diameter (μm) = [(50−A) / (C−A)] × (D−B) + B

In the formula, A is the sum of the mass of the polymer or particles remaining on the sieve sequentially from the sieve having a large mesh, and the accumulated mass is less than 50 mass% of the total mass, and the sieve closest to 50 mass%. Integrated value (g). C is the sum of the mass of the polymer or particles remaining on the sieve in order from the sieve with a large opening, and the accumulated mass is 50% by mass or more of the total mass, and the integration to the sieve closest to 50% by mass Value (g). D is the sieve opening (μm) when the integrated value of A is obtained. B is the sieve opening (μm) when the integrated value of C is obtained.

(4) 298.5 g of water is put into a beaker having a non-stirring dispersion time of 500 mL and the temperature of water is adjusted to 25 ° C. In this beaker, 1.5 g of carboxyl group-containing polymer or granular carboxyl group-containing polymer particles are charged all at once under a non-stirring condition, and the dispersion state of the polymer or particles is visually observed. Measure the time it takes for all of the particles to disperse without producing mamaco. In addition, dispersion | distribution means the state into which the input polymer or particle | grain becomes transparent gel form, and there is no generation | occurrence | production of Mamako.

(5) Dispersion time 175 g of water is placed in a 200 mL beaker, and the temperature of the water is adjusted to 25 ° C. To this beaker, 0.75 g of the carboxyl group-containing polymer or granular carboxyl group-containing polymer particles were charged all at once while stirring at a rotation speed of 500 rpm using a magnetic stirrer (chip 50 mm). The dispersion state is observed visually, and the time when the white color of the polymer or particle powder disappears at the bottom of the spiral is measured.

(6) 495 g of distilled water was put into a plastic beaker having a dissolution rate of 1 L, and an ultra-high speed multi-stirring system (manufactured by Primics Co., Ltd., trade name: TK Robotics, model number: A type, stirring section: TK Using a homomixer MII 2.5 type), a stirring state of 13500 rpm is obtained. 5 g of carboxyl group-containing polymer or granular carboxyl group-containing polymer particles are quickly added to the stirred distilled water and stirred for 1 minute or 2 minutes. Thereafter, stirring was stopped, and a part of the obtained slurry was centrifuged at 2000 rpm for 30 seconds using a centrifuge (trade name: conditioning mixer, model number: MX-201, manufactured by Shinky Corporation), and an aluminum cup (ASONE Corporation). Product, model number: No. 6) 1.5 g is measured from the slurry after centrifugation. Next, 1 drop of 1% by weight of a blue No. 1 aqueous solution as a colorant is added to the slurry, left to stand for 24 hours and naturally dried, and then the number of particles that can be visually determined as a particle shape is evaluated.

(7) Residual solvent concentration Into a 25 mL vial, 0.1 g of a sample (carboxyl group-containing polymer or granular carboxyl group-containing polymer particle) is precisely weighed, 0.75 mL of reagent-grade DMF and 0.75 mL of ion-exchanged water are added, After caulking the septa rubber and the aluminum seal cap, heat it with a 110 ° C. dryer for 2 hours. 1 mL of the gas phase portion in the vial was collected and gas chromatograph (GC-2014, manufactured by Shimadzu Corporation, detector: FID, filler: Thermon 1000, column: 3.0 mmΦ × 1 m glass column, column temperature: 80 ° C. Injection temperature: 180 ° C., detector temperature: 200 ° C.) for analysis. A calibration curve of the target residual solvent is prepared in advance, the residual solvent amount (mg) is calculated from the calibration curve, and the residual solvent concentration (ppm) is calculated by the following formula.
C (ppm) = [A / B] × 10 ⁶
In the formula, C represents a residual solvent concentration (ppm), A represents a residual solvent amount (mg) obtained by analysis using a gas chromatograph, and B represents a sampled amount (mg).

(8) Set a triangular funnel (diameter 120mmΦ x foot diameter 21mm) in a glass suction bottle with a dust generation capacity of 500mL, and suction mouth and dust meter (digital indicator P-5, manufactured by Shibata Rika Chemical Co., Ltd.) Are connected by a glass tube (outer diameter 10 mmΦ × 300 mm). A sample (carboxyl group-containing polymer or granular carboxyl group-containing polymer particle) of 3.0 g is charged into a triangular funnel from the height of 300 mm at the top, and at the same time, the start button of the dust meter is pushed and 1 minute later. Record the counter (counter (A) for sample). Before the sample is measured, a blank test is performed to obtain a counter (B) at the blank test, and the degree of dust generation is calculated by the following formula as an average value of N = 3.
Degree of dust generation (cpm) = AB
In the formula, A represents a counter (cpm) for the sample, and B represents a counter (cpm) for the blank test.

(9) Deionized water and carboxyl group-containing polymer or granular carboxyl group-containing polymer particles are charged into a 1 L glass beaker having a permeability of 0.5% by mass aqueous solution, and the magnetic stirrer is used for 3 hours. Stir to dissolve the polymer or particles. A 6% aqueous sodium hydroxide solution for neutralization was added to the resulting solution, and the neutralized solution was thickened by stirring with a S-type stirring blade for 1 hour in a three-one motor. The neutralized solution is put into a 10 mm quartz standard cell, rotated at 2500 rpm for 10 minutes with a centrifuge, removed, and measured for transmittance (%) at 425 nm with a spectrophotometer.

(10) The fluidity of the flowable carboxyl group-containing polymer or granular carboxyl group-containing polymer particles is measured using a bulk density measuring device (JIS Z8401). More specifically, after putting 10 g of the polymer or particles into the funnel into which the damper is inserted, the damper is pulled out, and the time for the polymer or particles to fall from the bottom of the funnel is measured and evaluated according to the following criteria: To do.
◎: Time to drop all polymers or particles within 20 seconds without hitting the funnel side ○: Time to drop all polymers or particles within 20 seconds by hitting the funnel side Δ: Hit the funnel side , The time for all of the polymer or particles to drop exceeds 20 seconds and 60
Within seconds X: The time when the polymer or particles all fall by hitting the funnel side exceeds 60 seconds

[Production Example 1]
As a (meth) acrylic acid alkyl ester having 18 kg (17.16 L) of acrylic acid and 18 to 24 carbon atoms in the alkyl group, in a 200 L reaction vessel equipped with a stirrer, thermometer, nitrogen blowing tube and cooling tube Blemmer VMA70 (manufactured by NOF Corporation, 10-20 parts by mass of stearyl methacrylate, 10-20 parts by mass of eicosanyl methacrylate, 59-80 parts by mass of behenyl methacrylate and tetracosanyl methacrylate content of 1% by mass or less 352 g of a mixture), 122 g of pentaerythritol allyl ether as a compound having two or more ethylenically unsaturated groups, 32.4 g of 2,2′-azobismethylisobutyrate as a radical polymerization initiator, and 64.4 kg of normal heptane as a polymerization solvent And 9.5 kg of ethyl acetate were charged. Subsequently, the solution was uniformly stirred and mixed, and then 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 polymerization 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 heptane and ethyl acetate, and further dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours, whereby a white powdery carboxyl group-containing polymer 17. 5 kg was obtained. The resulting carboxyl group-containing polymer had a bulk density of 0.18 g / cm ³ and a median particle size of 10 to 20 μm.

[Example 1]
20 kg of the carboxyl group-containing polymer obtained by the same method as in Production Example 1 was charged into a 200 L groove-type dryer, and under stirring, glyceryl monoisostearate (manufactured by Nikko Chemicals Co., Ltd., trade name: NIKKOL MGIS) 0 A solution prepared by dissolving 2 kg (1.03 parts by mass relative to 100 parts by mass of acrylic acid) in 39.8 kg of normal heptane / ethyl acetate = 95/5 (volume ratio) was added and mixed at room temperature for 1 hour. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 19.5 kg of a mixture.
The obtained mixture was continuously placed on a continuously moving belt with a thickness of 15 mm, and passed through a humidification tank (2 m) adjusted to a temperature of 85 to 95 ° C. and a relative humidity of 100% in 6 minutes. Agglomerates were obtained. The water content of the obtained aggregate was 7.0% by mass. The aggregate was continuously cooled and then crushed with a crusher, and dried under reduced pressure at 110 ° C. and 10 mmHG. The dried product was pulverized using a pulverizer (manufactured by Hadano Sangyo Co., Ltd., Makino type DD-2 type) to obtain granular carboxyl group-containing polymer particles. The above items were evaluated for the pulverized product. The results are shown in Table 1.

[Example 2]
20 kg of a carboxyl group-containing polymer obtained by the same method as in Production Example 1 was charged into a 200 L groove drier and stirred under a tetraglycerin pentaoleate (manufactured by Sakamoto Pharmaceutical Co., Ltd., trade name: SY Polyster). PO-3S) 0.6 kg (3.09 parts by mass with respect to 100 parts by mass of acrylic acid) was added to a solution of 39.4 kg of normal heptane / ethyl acetate = 95/5 (volume ratio). Mixed for hours. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 20 kg of a mixture.
The obtained mixture was continuously placed on a continuously moving belt with a thickness of 13 mm, and passed through a humidifying tank (2 m) adjusted to a temperature of 85 to 95 ° C. and a relative humidity of 100% in 6 minutes. Agglomerates were obtained. The water content of the obtained aggregate was 9.5% by mass. The aggregate was continuously cooled and then crushed with a crusher, and dried under reduced pressure at 110 ° C. and 10 mmHG. The dried product was pulverized using a pulverizer (Makino type DD-2, manufactured by Hadano Sangyo Co., Ltd.) to obtain granular carboxyl group-containing polymer particles. The above items were evaluated for the pulverized product. The results are shown in Table 1.

[Example 3]
20 kg of a carboxyl group-containing polymer obtained by the same method as in Production Example 1 was charged into a 200-L groove-type dryer, and under stirring, oleic acid mono-diglyceride (trade name: Sunsoft O-30V, Taiyo Kagaku) A solution prepared by dissolving 0.2 kg (1.03 parts by mass with respect to 100 parts by mass of acrylic acid) in 39.8 kg of normal heptane / ethyl acetate = 95/5 (volume ratio) is added, and the temperature is 1 hour at room temperature. Mixed. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 19.5 kg of a mixture.
The obtained mixture was continuously placed on a continuously moving belt with a thickness of 15 mm, and passed through a humidification tank (2 m) adjusted to a temperature of 85 to 95 ° C. and a relative humidity of 100% in 10 minutes. Agglomerates were obtained. The water content of the obtained aggregate was 13.0% by mass. The aggregate was continuously cooled and then crushed with a crusher, and dried under reduced pressure at 110 ° C. and 10 mmHG. The dried product was pulverized using a pulverizer (manufactured by Hadano Sangyo Co., Ltd., Makino type DD-2 type) to obtain granular carboxyl group-containing polymer particles. The above items were evaluated for the pulverized product. The results are shown in Table 1.

[Example 4]
20 kg of a carboxyl group-containing polymer obtained by the same method as in Production Example 1 was charged into a 200 L groove-type dryer, and under stirring, glycerin monooleate (trade name: Riquemar OL-100E, manufactured by Riken Vitamin Co., Ltd.). A solution prepared by dissolving 0.8 kg (4.11 parts by mass with respect to 100 parts by mass of acrylic acid) in 39.2 kg of normal heptane / ethyl acetate = 95/5 (volume ratio) was added and mixed at room temperature for 1 hour. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 20 kg of a mixture.
The obtained mixture was continuously placed on a continuously moving belt with a thickness of 18 mm, and passed through a humidification tank (2 m) adjusted to a temperature of 85 to 95 ° C. and a relative humidity of 100% in 10 minutes. Agglomerates were obtained. The water content of the obtained aggregate was 10.0% by mass. The aggregate was continuously cooled and then crushed with a crusher, and dried under reduced pressure at 110 ° C. and 10 mmHG. The dried product was pulverized using a pulverizer (manufactured by Hadano Sangyo Co., Ltd., Makino type DD-2 type) to obtain granular carboxyl group-containing polymer particles. The above items were evaluated for the pulverized product. The results are shown in Table 1.

[Example 5]
20 kg of a carboxyl group-containing polymer obtained by the same method as in Production Example 1 was charged into a 200 L groove-type dryer, and under stirring, polyoxyethylene hydrogenated castor oil (produced by Nippon Emulsion Co., Ltd., trade name: EMALEX RWIS-350) 0.2 kg (1.03 parts by mass with respect to 100 parts by mass of acrylic acid) dissolved in normal heptane / ethyl acetate = 95/5 (volume ratio) 39.8 kg was added, For 1 hour. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 19.5 kg of a mixture.
The obtained mixture was continuously placed on a continuously moving belt with a thickness of 15 mm, and passed through a humidification tank (2 m) adjusted to a temperature of 85 to 95 ° C. and a relative humidity of 100% in 10 minutes. Agglomerates were obtained. The water content of the obtained aggregate was 12.5% by mass. The aggregate was continuously cooled and then crushed with a crusher, and dried under reduced pressure at 110 ° C. and 10 mmHG. The dried product was pulverized using a pulverizer (manufactured by Hadano Sangyo Co., Ltd., Makino type DD-2 type) to obtain granular carboxyl group-containing polymer particles. The above items were evaluated for the pulverized product. The results are shown in Table 1.

[Example 6]
20 kg of a carboxyl group-containing polymer obtained by the same method as in Production Example 1 was charged into a 200 L groove type dryer, and under stirring, polyglyceryl oleate-2 (manufactured by Nippon Emulsion Co., Ltd., trade name: EMALEX MOG) -2) A solution prepared by dissolving 0.1 kg (0.51 parts by mass with respect to 100 parts by mass of acrylic acid) in normal heptane / ethyl acetate = 95/5 (volume ratio) of 39.9 kg was added, and the mixture was at room temperature for 1 hour. Mixed. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 20 kg of a mixture.
The obtained mixture was continuously placed on a continuously moving belt with a thickness of 15 mm, and passed through a humidification tank (2 m) adjusted to a temperature of 85 to 95 ° C. and a relative humidity of 100% in 15 minutes. Agglomerates were obtained. The water content of the obtained aggregate was 18.0% by mass. The aggregate was continuously cooled and then crushed with a crusher, and dried under reduced pressure at 110 ° C. and 10 mmHG. The dried product was pulverized using a pulverizer (manufactured by Hadano Sangyo Co., Ltd., Makino type DD-2 type) to obtain granular carboxyl group-containing polymer particles. The above items were evaluated for the pulverized product. The results are shown in Table 1.

[Example 7]
20 kg of the carboxyl group-containing polymer obtained by the same method as in Production Example 1 was charged into a 200 L groove-type dryer, and under stirring, glyceryl monoisostearate (manufactured by Nikko Chemicals Co., Ltd., trade name: NIKKOL MGIS) 0 0.2 kg (1.03 parts by mass with respect to 100 parts by mass of acrylic acid) and 0.2 kg of polyoxyethylene hydrogenated castor oil (made by Nippon Emulsion Co., Ltd., trade name: EMALEX RWIS-350) (100 parts by mass of acrylic acid) The solution which melt | dissolved 1.03 mass part) in normal heptane / ethyl acetate = 95/5 (volume ratio) 39.4kg was added, and it mixed at normal temperature for 1 hour. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 19.5 kg of a mixture.
The obtained mixture was continuously placed on a continuously moving belt with a thickness of 15 mm, and passed through a humidification tank (2 m) adjusted to a temperature of 85 to 95 ° C. and a relative humidity of 100% in 10 minutes. Agglomerates were obtained. The water content of the obtained aggregate was 12.0% by mass. The aggregate was continuously cooled and then crushed with a crusher, and dried under reduced pressure at 110 ° C. and 10 mmHG. The dried product was pulverized using a pulverizer (manufactured by Hadano Sangyo Co., Ltd., Makino type DD-2 type) to obtain granular carboxyl group-containing polymer particles. The above items were evaluated for the pulverized product. The results are shown in Table 1.

[Comparative Example 1]
The above items were evaluated for the carboxyl group-containing copolymer obtained in Production Example 1. The results are shown in Table 1.

[Comparative Example 2]
The carboxyl group-containing polymer obtained in Production Example 1 was continuously placed on a continuously moving belt with a thickness of 15 mm, and the inside of a humidifying tank (2 m) adjusted to a temperature of 85 to 95 ° C. and a relative humidity of 100%. Was passed in 6 minutes to obtain an aggregate of a carboxyl group-containing polymer. The water content of the obtained aggregate was 7.5% by mass. The aggregate was continuously cooled and then crushed with a crusher, and dried under reduced pressure at 110 ° C. and 10 mmHG. The dried product is pulverized using a pulverizer (manufactured by Hadano Sangyo Co., Ltd., Makino type DD-2 type), and the ON product is cut with a 300 μm sieve to obtain granular carboxyl group-containing polymer particles having a median particle size of 200 μm. It was. The above items were evaluated for the pulverized product. The results are shown in Table 1.

[Comparative Example 3]
20 kg of a carboxyl group-containing polymer obtained by the same method as in Production Example 1 was charged into a 200 L groove drier and stirred under a tetraglycerin pentaoleate (manufactured by Sakamoto Pharmaceutical Co., Ltd., trade name: SY Polyster). PO-3S) 1.2 kg (6.17 parts by mass with respect to 100 parts by mass of acrylic acid) in normal heptane / ethyl acetate = 95/5 (volume ratio) 38.4 kg was added, and 1 at room temperature was added. Mixed for hours. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 21 kg of a mixture.
The obtained mixture was continuously placed on a continuously moving belt with a thickness of 15 mm, and passed through a humidification tank (2 m) adjusted to a temperature of 85 to 95 ° C. and a relative humidity of 100% in 6 minutes. Agglomerates were obtained. The water content of the obtained aggregate was 6.5% by mass. The aggregate was continuously cooled and then crushed with a crusher, and dried under reduced pressure at 110 ° C. and 10 mmHG. The dried product was pulverized using a pulverizer (manufactured by Hadano Sangyo Co., Ltd., Makino type DD-2 type) to obtain granular carboxyl group-containing polymer particles. The above items were evaluated for the pulverized product. The results are shown in Table 1.

[Comparative Example 4]
20 kg of the carboxyl group-containing polymer obtained by the same method as in Production Example 1 was charged into a 200 L groove-type dryer, and under stirring, glyceryl monoisostearate (manufactured by Nikko Chemicals Co., Ltd., trade name: NIKKOL MGIS) 0 A solution prepared by dissolving 0.02 kg (0.10 parts by mass with respect to 100 parts by mass of acrylic acid) in 39.4 kg of normal heptane / ethyl acetate = 95/5 (volume ratio) was added and mixed at room temperature for 1 hour. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 20 kg of a mixture.
The obtained mixture was continuously placed on a continuously moving belt with a thickness of 15 mm, and passed through a humidification tank (2 m) adjusted to a temperature of 85 to 95 ° C. and a relative humidity of 100% in 10 minutes. Agglomerates were obtained. The water content of the obtained aggregate was 12.5% by mass. The aggregate was continuously cooled and then crushed with a crusher, and dried under reduced pressure at 110 ° C. and 10 mmHG. The dried product was pulverized using a pulverizer (Makino type DD-2, manufactured by Hadano Sangyo Co., Ltd.) to obtain granular carboxyl group-containing polymer particles. The above items were evaluated for the pulverized product. The results are shown in Table 1.

[Comparative Example 5]
20 kg of a carboxyl group-containing polymer obtained by the same method as in Production Example 1 was charged into a 200-L groove-type dryer, and under stirring, oleic acid mono-diglyceride (trade name: Sunsoft O-30V, Taiyo Kagaku) A solution prepared by dissolving 0.2 kg (1.03 parts by mass with respect to 100 parts by mass of acrylic acid) in 39.8 kg of normal heptane / ethyl acetate = 95/5 (volume ratio) is added, and the temperature is 1 hour at room temperature. Mixed. This was dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 19.5 kg of a mixture.
The obtained mixture was continuously placed on a continuously moving belt with a thickness of 13 mm, and passed through a humidification tank (2 m) adjusted to a temperature of 85 to 95 ° C. and a relative humidity of 100% in 15 minutes. Agglomerates were obtained. The water content of the obtained aggregate was 25.0% by mass. The aggregate was continuously cooled and then crushed with a crusher, and dried under reduced pressure at 110 ° C. and 10 mmHG. The dried product was pulverized using a pulverizer (manufactured by Hadano Sangyo Co., Ltd., Makino type DD-2 type) to obtain granular carboxyl group-containing polymer particles. The above items were evaluated for the pulverized product. The results are shown in Table 1.

From the results in Table 1, the granular carboxyl group-containing polymer particles (Examples 1 to 7) obtained by the production method of the present invention have no dispersibility in water without formation of mamaco even under non-stirring conditions. In addition, the dissolution rate is the same level as that of the finely powdered carboxyl group-containing polymer (Comparative Example 1) before granulation, and since the amount of residual solvent is small and dust generation is remarkably suppressed, It is also preferable from the viewpoint of safety and health and the environment.
Further, when at least one compound selected from the group consisting of polyhydric alcohol fatty acid esters and polyhydric alcohol fatty acid ester alkylene oxide adducts was not added (Comparative Example 2), dispersion in water during stirring and dissolution The properties are relatively good, but under the non-stirring conditions, it is easy for Mamako to be produced under the influence of a small amount of fine powder, and the granular carboxyl group-containing polymer particles obtained by the production method of the present invention (Examples 1 to 7) Compared to this, the dissolution rate tends to be slow, and further, the suppression of dust generation is insufficient.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the granular carboxyl group containing polymer particle which is excellent in the dispersibility to water, is low dust generation, is highly fluid, and has little residual solvent amount can be provided. Moreover, according to this invention, the granular carboxyl group containing polymer particle obtained by the manufacturing method of this granular carboxyl group containing polymer particle can be provided.

Claims (9)

A step of polymerizing a monomer mainly composed of (meth) acrylic acid to produce a carboxyl group-containing polymer;
Adding at least one compound selected from the group consisting of a polyhydric alcohol fatty acid ester and a polyhydric alcohol fatty acid ester alkylene oxide adduct to the carboxyl group-containing polymer to produce a mixture;
Humidifying the mixture to a moisture content of 3 to 20% by mass to produce an aggregate of the mixture;
And drying the aggregate of the mixture, followed by crushing
In the step of preparing the mixture, the amount of at least one compound selected from the group consisting of the polyhydric alcohol fatty acid ester and the polyhydric alcohol fatty acid ester alkylene oxide adduct is 100 parts by mass of the (meth) acrylic acid. The manufacturing method of the granular carboxyl group containing polymer particle characterized by being 0.2-5 mass parts with respect to. In the step of producing a carboxyl group-containing polymer, 100 parts by weight of (meth) acrylic acid, 1 to 10 parts by weight of alkyl (meth) acrylate having 18 to 24 carbon atoms, and ethylenic unsaturated The method for producing granular carboxyl group-containing polymer particles according to claim 1, wherein 0.01 to 1 part by mass of a compound having two or more groups is polymerized to prepare a carboxyl group-containing polymer. 3. The polyhydric alcohol in the polyhydric alcohol fatty acid ester is at least one selected from the group consisting of glycerin, polyglycerin, trimethylolpropane, pentaerythritol, sorbit and sorbitan. A method for producing granular carboxyl group-containing polymer particles. The method for producing granular carboxyl group-containing polymer particles according to claim 1, 2, or 3, wherein the fatty acid in the polyhydric alcohol fatty acid ester is a fatty acid having 10 to 30 carbon atoms. Fatty acid in polyhydric alcohol fatty acid ester is from stearic acid, isostearic acid, distearic acid, diisostearic acid, tristearic acid, triisostearic acid, tetraisostearic acid, oleic acid, dioleic acid, trioleic acid, pentaoleic acid, dekaoleic acid The method for producing granular carboxyl group-containing polymer particles according to claim 1, 2, 3, or 4, wherein the method is at least one selected from the group consisting of: The polyhydric alcohol in the polyhydric alcohol fatty acid ester alkylene oxide adduct is at least one selected from the group consisting of glycerin, polyglycerin, sorbit and sorbitan, 6. A method for producing granular carboxyl group-containing polymer particles according to 5. Polyhydric alcohol fatty acid ester alkylene oxide adducts are polyoxyethylene hydrogenated castor oil, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil isostearate, polyoxyethylene hydrogenated castor oil triisostearate and polyoxyethylene sorbite tetraoleate The method for producing granular carboxyl group-containing polymer particles according to claim 1, 2, 3, 4, 5 or 6, wherein the method is at least one selected from the group consisting of: In the step of producing an aggregate of the mixture, the mixture is humidified by passing through a humidifying tank, the temperature in the humidifying tank is 50 to 100 ° C., the relative humidity in the humidifying tank is 70 to 100%, and 8. The method for producing granular carboxyl group-containing polymer particles according to claim 1, wherein the time for passing through the humidifying tank is 2 to 15 minutes. Granular carboxyl group-containing polymer particles obtained by the method for producing granular carboxyl group-containing polymer particles according to claim 1, 2, 3, 4, 5, 6, 7, or 8, wherein the following 1) to 4): ):
1) Residual solvent amount is 5000 ppm or less 2) Median particle size is 75 to 240 μm
3) Granular carboxyl group-containing polymer particles characterized by having a dust generation degree of 100 cpm or less and 4) a bulk density of 0.35 g / cm ³ or more.