WO2013008818A1

WO2013008818A1 - Cured amino resin particle dispersion and method for producing same

Info

Publication number: WO2013008818A1
Application number: PCT/JP2012/067593
Authority: WO
Inventors: 康史鹿内; 将大飛田; 小澤　雅昭
Original assignee: 日産化学工業株式会社
Priority date: 2011-07-14
Filing date: 2012-07-10
Publication date: 2013-01-17
Also published as: JPWO2013008818A1

Abstract

[Problem] To provide a cured amino resin particle dispersion exhibiting excellent dispersibility in an organic solvent, particularly in a water-insoluble organic solvent, and a method for producing the cured amino resin particle dispersion. [Solution] Disclosed is a cured amino resin particle dispersion in which cured amino resin particles and hydrophobic inorganic compound particles are dispersed in an organic solvent. Also disclosed is a method for producing the cured amino resin particle dispersion.

Description

Cured amino resin particle dispersion and production method thereof

The present invention relates to a cured amino resin particle dispersion and a method for producing the same, and in particular, relates to a dispersion excellent in dispersibility of resin particles in a non-aqueous medium and a method for producing the same.

Various methods have been proposed for producing cured amino resin particles. An initial condensate obtained by reacting benzoguanamine, melamine, and formaldehyde in a predetermined pH range is added to a hydrophilic polymer protective colloid aqueous solution under stirring and emulsified, and then a curing catalyst such as an acid is added to cure the reaction. Is disclosed (see Patent Document 1). A hydrophilic initial condensate of melamine and / or benzoguanamine and formaldehyde is suspended in an aqueous solution containing an anionic or nonionic surfactant in the presence of an alkylbenzenesulfonic acid having an alkyl group having 10 to 18 carbon atoms. A method of condensation curing under turbidity is disclosed (see Patent Document 2). In addition, an aqueous solution of an initial condensate of a melamine compound and an aldehyde compound is produced in a suspension of colloidal silica having an average particle diameter of 5 to 70 nm, and an acid catalyst is added to the aqueous solution to precipitate spherical composite cured melamine resin particles. Is disclosed (see Patent Document 3).

It is known that the cured amino resin particles obtained by these methods generally have a large specific gravity and a low dispersibility in water or an organic solvent and easily aggregate and settle. For this reason, when applying an aqueous dispersion or an organic solvent dispersion of cured amino resin particles, it is difficult to obtain a uniform coating film because the cured amino resin particles aggregate and settle in the dispersion medium. Further, the aggregation / sedimentation of the cured amino resin particles has made the workability more difficult as the scale becomes larger, and has been an important solution in various application processes.

In order to solve the above problems, as a method of stably dispersing cured amino resin particles in an aqueous medium, a method of surface treatment with water-soluble polymers having a carboxyl group in the molecule has been proposed (see Patent Document 4). ).
In this method, the cured amino resin particles are surface-treated with water-soluble polymers having a carboxyl group in the molecule, so that the settling rate of the cured amino resin particles in the aqueous medium is slowed and the dispersion stability is improved. It is described to do.

JP 50-45852 A JP-A-62-68811 JP 2002-327036 A JP 2008-101040 A

As described above, the conventionally proposed dispersion method of cured amino resin particles is characterized by using water-soluble polymers, and only the improvement of dispersion stability in an aqueous medium is described. In addition, although water-soluble alcohols, ethers, and amides are shown as usable organic solvents, dispersibility improvement and dispersion methods in organic solvents, especially organic solvents insoluble in water, are studied. Has not been made.
In recent years, while the improvement in dispersibility of cured amino resin particles in a non-aqueous medium has been studied, the present invention pays attention to such problems, and a cured amino resin excellent in dispersibility in an organic solvent, particularly in a water-insoluble organic solvent. An object is to provide a particle dispersion and a method for producing the cured amino resin particle dispersion.

As a result of diligent investigations to achieve the above object, the present inventors have found that when dispersing the cured amino resin particles in an organic solvent insoluble in water, by coexisting hydrophobic inorganic compound particles, The present invention was completed by finding out that the dispersion is excellent in dispersibility by suppressing sedimentation.

That is, as a first aspect, the present invention relates to a cured amino resin particle dispersion in which cured amino resin particles and hydrophobic inorganic compound particles are dispersed in an organic solvent.
As a second aspect, the present invention relates to the dispersion according to the first aspect, in which the hydrophobic inorganic compound particles adhere to the surface of the cured amino resin particles to form a composite.
As a third aspect, the dispersion according to the first aspect or the second aspect, in which the hydrophobic inorganic compound particles are contained in an amount of 0.01 to 200 parts by mass with respect to 100 parts by mass of the cured amino resin particles. Regarding liquids.
As a fourth aspect, the present invention relates to the dispersion according to any one of the first aspect to the third aspect, in which the hydrophobic inorganic compound particles are hydrophobic silica particles.
As a fifth aspect, in any one of the first to fourth aspects, the organic solvent is contained in an amount of 10 to 100,000 parts by mass with respect to 100 parts by mass of the cured amino resin particles. Relates to the described dispersion.
As a sixth aspect, the present invention relates to a method for producing a cured amino resin particle dispersion, comprising a step of mixing cured amino resin particles and hydrophobic inorganic compound particles in an organic solvent at a temperature between the melting point and the boiling point of the organic solvent. .
As a seventh aspect, production of a cured amino resin particle dispersion liquid comprising a step of mixing a cured amino resin particle and an organosol of hydrophobic inorganic compound particles in an organic solvent at a temperature between the melting point and the boiling point of the organic solvent. Regarding the method.
As an eighth aspect, the present invention relates to the production method according to the seventh aspect, wherein the organosol of the hydrophobic inorganic compound particles is an organosol of hydrophobic silica particles.
As a ninth aspect, any one of the sixth to eighth aspects, wherein the hydrophobic inorganic compound particles are used in an amount of 0.01 to 200 parts by mass with respect to 100 parts by mass of the cured amino resin particles. The manufacturing method according to one item.

The cured amino resin particle dispersion of the present invention is a dispersion having improved dispersibility in an organic solvent, particularly a water-insoluble organic solvent, by coexisting hydrophobic inorganic compound particles. The cured amino resin in the dispersion Aggregation of particles is suppressed and redispersibility is excellent. Therefore, when the cured amino resin particle dispersion is applied to a substrate or the like, a coating film in which the cured amino resin particles are uniformly dispersed is obtained and can be suitably used in various application processes.
Moreover, since the aggregation and sedimentation of the cured amino resin particles, which are difficult to work with as the scale increases, can be suppressed as seen in the conventional cured amino resin particle dispersion, It is possible to remarkably improve the workability when it is up.

Further, the cured amino resin particle dispersion of the present invention takes advantage of the characteristics of the cured amino resin particles contained therein that are high in refractive index, water resistance, solvent resistance, and heat resistance, and various abrasives, paints, inks, matting agents. , Resin filler, resin film slipperiness improver, chromatographic filler, antiwear agent, liquid crystal display spacer, light diffusion sheet light diffusion agent, pigment for electrophoretic display devices such as digital paper, touch panel hard coat agent , Toner and toner external additives, gas adsorbents, acidic adsorbents, solar cell electrodes, photocatalysts for water splitting, optical materials, magnetic materials, conductive materials, flame retardants, papermaking materials, fiber treatment materials, printing It can be suitably used as an unevenness imparting agent for a printing original plate.

FIG. 1 is a diagram showing a particle size distribution chart immediately after a sample of a cured amino resin particle dispersion prepared in Example 1 is measured by laser diffraction / scattering particle size distribution measurement. FIG. 2 is a diagram showing a particle size distribution chart immediately after the sample of the cured amino resin particle dispersion prepared in Comparative Example 1 is measured by laser diffraction / scattering particle size distribution measurement. FIG. 3 is a diagram showing a particle size distribution chart 10 minutes after the introduction of a sample of the cured amino resin particle / organic particle dispersion prepared in Example 17 by laser diffraction / scattering particle size distribution measurement. FIG. 4 is a diagram showing a particle size distribution chart 10 minutes after sample introduction of the cured amino resin particle / organic particle dispersion prepared in Comparative Example 8 by laser diffraction / scattering particle size distribution measurement.

Hereinafter, the present invention will be described in more detail.

[Dispersion containing cured amino resin particles and hydrophobic inorganic compound particles]
<Curing amino resin particles>
As the cured amino resin particles of the present invention, known cured urea resin particles, cured melamine resin particles, cured guanamine resin particles, co-condensed resin particles thereof, and the like can be used. Further, colored cured amino resin particles containing a known dye or pigment can also be used. The average particle diameter of the cured amino resin particles is not particularly limited, but those having 0.05 to 100 μm can be preferably used. In the present specification, the average particle diameter (μm) is a 50% volume diameter (median diameter) obtained by measurement by a laser diffraction / scattering method based on the Mie theory.

Among these, it is preferable to use spherical composite cured melamine resin particles containing melamine resin and silica described in JP-A-2002-327036.
That is, spherical composite cured melamine resin particles containing a melamine resin and silica are, for example, (a) a basic solution of a melamine compound and an aldehyde compound in a suspension of colloidal silica having an average particle diameter of 5 to 70 nm in an aqueous medium. A step of generating an aqueous solution of an initial condensate of water-soluble melamine resin by reacting under conditions, and an acid catalyst is added to the aqueous solution obtained in steps (b) and (a) to form a spherical composite cured melamine It is manufactured including a step of depositing resin particles.

Examples of the melamine compound used in the step (a) include melamine, a substituted melamine compound in which the amino group hydrogen of melamine is substituted with an alkyl group, an alkenyl group, or a phenyl group [US Pat. No. 5,998,573 ( Corresponding Japanese Patent: JP-A-9-143238). And a substituted melamine compound in which the hydrogen of the amino group of melamine is substituted with a hydroxyalkyl group, a hydroxyalkyloxyalkyl group, or an aminoalkyl group [US Pat. No. 5,322,915 (corresponding Japanese Patent: Japanese Patent Laid-Open No. 202157). ] Can be used. Of these, inexpensive melamine is most preferred.
Also, melamine compounds and part of melamine compounds are replaced with ureas such as urea, thiourea and ethylene urea, guanamines such as benzoguanamine and acetoguanamine, phenols such as phenol, cresol, alkylphenol, resorcin, hydroquinone and pyrogallol, and aniline. Can also be used as a mixture.

Examples of the aldehyde compound used in the step (a) include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, furfural and the like, but formaldehyde and paraformaldehyde which are inexpensive and have good reactivity with the melamine compound are preferable. As the aldehyde compound, it is preferable to use an aldehyde compound having an amount of 1.1 to 6.0 mol, particularly 1.2 to 4.0 mol, based on 1 mol of the melamine compound, per effective aldehyde group.

Water is most preferable as the medium used in the step (a). A mixed solution in which a part of water is replaced with an organic solvent soluble in water can also be used. In this case, an organic solvent capable of dissolving the initial condensate of melamine resin is preferably selected. Preferred organic solvents include alcohols such as methanol, ethanol, isopropanol and propanol; ethers such as dioxane, tetrahydrofuran (THF) and 1,2-dimethoxyethane; N, N-dimethylformamide (DMF), dimethyl sulfoxide and the like Examples include polar solvents.

As the colloidal silica used in the step (a), those having an average particle diameter of 5 to 70 nm are used.
Here, the average particle diameter of colloidal silica is a specific surface area diameter obtained by measurement by a nitrogen adsorption method (BET method). The average particle diameter (specific surface area diameter) (Dnm) is given by the formula D = 2720 / S from the specific surface area Sm ² / g as measured by the nitrogen adsorption method. Although powdered colloidal silica such as precipitated silica powder and vapor phase method silica powder can be used, it is preferable to use a colloidal silica sol stably dispersed to the primary particle level in a medium. There are two types of colloidal silica sols: aqueous silica sol and organosilica sol, both of which can be used. However, since an aqueous medium is used for the production of melamine resin, aqueous silica sol can be used from the viewpoint of dispersion stability of colloidal silica sol. Most preferred. The silica concentration in the colloidal silica sol is preferably from 5 to 50% by mass because it is generally commercially available and can be easily obtained.
When the average particle diameter of colloidal silica exceeds 70 nm, the composite cured melamine resin that precipitates in the subsequent step (b) is difficult to become spherical particles. In general, the average particle diameter of the spherical composite cured melamine resin particles tends to be smaller as the melamine resin concentration is lower and the average particle diameter of the colloidal silica is smaller.
The amount of colloidal silica added is preferably 0.5 to 100 parts by weight, particularly 1 to 50 parts by weight, based on 100 parts by weight of the melamine compound. If the addition amount is less than 0.5 parts by mass, it is difficult to obtain spherical composite cured melamine resin particles in step (b). Further, even if the addition amount exceeds 100 parts by mass, spherical composite cured melamine resin particles can be obtained. However, in this case, finer non-spherical aggregated particles are produced as a by-product than spherical composite cured melamine resin particles, which is not preferable.

In the step (a), the reaction between the melamine compound and the aldehyde compound is performed under basic conditions. It is preferable to carry out the reaction by using a basic catalyst used for a general melamine resin and adjusting the pH of the reaction solution to 7-10. As the basic catalyst, for example, sodium hydroxide, potassium hydroxide, aqueous ammonia and the like can be suitably used. The reaction is usually carried out at 50 to 80 ° C. As a result, an aqueous solution of an initial condensate of melamine resin soluble in water having a molecular weight of about 200 to 700 is prepared.

(B) There is no restriction | limiting in particular as an acid catalyst used by hardening reaction of a process, such as hydrochloric acid, a sulfuric acid, nitric acid, phosphoric acid, methanesulfonic acid, benzenesulfonic acid, paratoluenesulfonic acid, alkylbenzenesulfonic acid, sulfamic acid, etc. Examples include sulfonic acids, formic acid, oxalic acid, benzoic acid, and organic acids such as phthalic acid.
In the step (b), an acid catalyst is added to the aqueous solution of the initial condensate obtained in the step (a) to carry out a curing reaction. Usually, the cured melamine resin particles are deposited within a few minutes after the addition of the acid catalyst. The curing reaction is preferably performed at 70 to 100 ° C. by adjusting the pH of the reaction solution to 3 to 7 with an acid catalyst.

The spherical composite cured melamine resin particles in which colloidal silica is unevenly distributed in the vicinity of the particle surface produced in the above steps (a) and (b) can be obtained by drying a solid content obtained by general filtration or centrifugation, or by resin By directly spray-drying an aqueous dispersion slurry of particles, it can be obtained as powder particles. If the dried powder particles are agglomerated between particles, such as mixers with shearing force such as homomixers, Henschel mixers, and Roedige mixers, pin disc mills, pulverizers, inomizers, counter jet mills, etc. When appropriately treated with a pulverizer, interparticle aggregation can be loosened without destroying the spherical particles.

The spherical composite cured melamine resin particles containing melamine resin and silica thus obtained are spherical composite cured melamine resin particles in which colloidal silica is unevenly distributed in the vicinity of the particle surface, and the particles are spherical and have independent primary particles. In addition, no pores are present, and colloidal silica is present in the vicinity of the particle surface within a depth of about 0.2 μm from the outermost surface of the particle. Although colloidal silica is embedded in the cured melamine resin near the particle surface or is fixed on the particle surface, the outermost surface component is usually a cured melamine resin. The particles do not use water-soluble protective colloids or surfactants at the time of production, and since these particles are not present on the particle surface, it is assumed that the particle surface is charged positively, and a hydrophobic inorganic compound It is thought that the particles can be efficiently attached and combined.
Further, spherical composite cured melamine resin particles containing melamine resin and silica, which are colored with a fluorescent dye or a water-soluble dye, can also be used.

<Hydrophobic inorganic compound particles>
In the present invention, the hydrophobic inorganic compound particles represent inorganic compound particles that have been subjected to a surface treatment (hydrophobization treatment) excellent in dispersibility in an organic solvent.
Examples of the inorganic compound particles include magnesium oxide, aluminum oxide, silicon oxide, calcium oxide, titanium oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, yttrium oxide, zirconium oxide, tin oxide, and antimony oxide. Metal oxide particles such as cerium oxide and composite oxides thereof; metal nitride particles such as silicon nitride and titanium nitride; metal sulfide particles such as iron sulfide and zinc sulfide; aluminum, iron, nickel, copper, zinc, Examples thereof include metal particles such as palladium, silver, platinum, and gold. Among these, metal oxide particles such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, antimony oxide, and cerium oxide are preferable. The particle diameter of these inorganic compound particles is not particularly limited as long as the dispersibility of the cured amino resin particles in an organic solvent is improved, but preferably 1/5 of the average particle diameter of the cured amino resin particles. It has the following primary particle size.

The hydrophobization treatment may be performed by a conventionally known method. Specifically, for example, chlorosilanes such as trimethylchlorosilane and triphenylchlorosilane; monoalkoxysilanes such as methoxytrimethylsilane, ethoxytrimethylsilane, trimethyl (propoxy) silane, and ethoxytriphenylsilane; dimethoxydimethylsilane, dimethoxy (methyl) ) Dialkoxysilanes such as (phenyl) silane, dimethoxydiphenylsilane, diethoxydimethylsilane; trialkoxysilanes such as trimethoxy (methyl) silane, trimethoxy (ethyl) silane, trimethoxy (phenyl) silane, triethoxy (methyl) silane Siloxanes such as hexamethyldisiloxane, silazanes such as hexamethyldisilazane; trimethylsilanol, triethylsilanol, triphenylsilanol, etc. Such as silanols, surface treatment can be exemplified by silylating agent or a silane coupling agent.

The hydrophobic inorganic compound particles used in the present invention may be a powder itself or a sol dispersed in an organic solvent. In addition, from the viewpoint of adhesion to cured amino resin particles, particularly spherical composite cured melamine resin particles containing melamine resin and silica, those in which the particle surface is negatively charged in an organic solvent are preferred.
Specifically, hydrophobic silica particles are preferable.

Examples of hydrophobic silica include precipitated silica, fine silica (generally referred to as fumed silica) powder produced by flame pyrolysis of chlorosilane, and hydrophobizing agents such as surfactants, silicone oils, or Hydrophobized by contact with a silylating agent such as alkylhalogenosilane, alkylalkoxysilane, alkyldisilazane, etc., or contacted with a silylating agent in a hydrophilic organic solvent containing water. Things.
In addition, a silica sol using a hydrophilic organic solvent such as alcohol or a mixed solvent of water and a hydrophilic organic solvent as a dispersion medium is reacted with a silylating agent such as alkylhalogenosilane, alkylalkoxysilane, or alkyldisiloxane. Hydrophobic silica powder obtained by removing can also be mentioned.

The content of the hydrophobic inorganic compound particles in the dispersion of the present invention is 0.01 to 200 parts by weight, more preferably 0.02 to 150 parts by weight, and particularly preferably 0 to 100 parts by weight of the cured amino resin particles. It is preferably 1 to 20 parts by mass. By setting the content to 0.01 parts by mass or more, the effect of the hydrophobic inorganic compound particles, that is, the dispersibility in an organic solvent can be improved. Further, by setting the amount to 200 parts by mass or less, not only the excessive increase in specific gravity of the cured amino resin particles having the hydrophobic inorganic compound particles attached to the surface thereof, but also an excessive hydrophobic inorganic compound that does not contribute to improvement in dispersibility Particles are reduced, which is economically advantageous.

<Organic solvent>
The organic solvent used as the dispersion medium in the dispersion liquid of the present invention is not particularly limited, and examples thereof include ethers such as tetrahydrofuran (THF), diethyl ether, dimethoxyethane; ethyl acetate, isopropyl acetate, n-acetate Esters such as propyl, isobutyl acetate and n-butyl acetate; halogenated hydrocarbons such as methylene chloride and chloroform; N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAC), N-methyl Amides such as -2-pyrrolidone (NMP); ketones such as acetone, ethyl methyl ketone (MEK), isobutyl methyl ketone (MIBK), cyclohexanone; alcohols such as methanol, ethanol, isopropanol, n-propanol; n- Heptane, n-hexane, Aliphatic hydrocarbons such cyclohexane and the like; benzene, toluene, xylene, and aromatic hydrocarbons such as ethylbenzene and the like. These organic solvents may be used by mixing one kind singly or.
In particular, since a dispersion of an organic solvent that is insoluble and hardly soluble in water is advantageous for various subsequent processes, the organic solvent used as the dispersion of the present invention includes toluene, xylene, MEK, MIBK, cyclohexanone, Ethyl acetate or the like or a mixed solvent thereof is preferable. Moreover, these organic solvents can be used individually by 1 type or in mixture of 2 or more types.
In the production of the cured amino resin particle dispersion described later, the organic solvent used for the organosol of the hydrophobic inorganic compound particles can also be selected from the <organic solvent> listed here. Here, the organic solvent used for the organosol and the organic solvent used as a dispersion medium of the dispersion may be the same or different.

The ratio of the organic solvent in the cured amino resin particle dispersion of the present invention is arbitrary, but is 10 to 100,000 parts by weight, particularly 100 to 1,000 parts by weight, based on 100 parts by weight of the cured amino resin particles. It is preferable.
Moreover, when the cured amino resin particle dispersion was obtained using the organosol of hydrophobic inorganic compound particles, the ratio of the organic solvent in the cured amino resin particle dispersion was used as the organic solvent used in the organosol and the dispersion medium. It is a ratio of the total amount with the organic solvent, and is preferably 10 to 100,000 parts by mass, particularly preferably 100 to 1,000 parts by mass with respect to 100 parts by mass of the cured amino resin particles.

[Production of Cured Amino Resin Particle Dispersion]
The cured amino resin particle dispersion of the present invention can be obtained by mixing cured amino resin particles and hydrophobic inorganic compound particles in an organic solvent. It can also be obtained by taking out each as powder particles once and mixing these powders with an organic solvent, for example, after mixing them at room temperature as desired. Alternatively, it can also be obtained by mixing cured amino resin particles and organosol of hydrophobic inorganic compound particles in an organic solvent.

The temperature at which the cured amino resin particles and the hydrophobic inorganic compound particles or the organosol of the hydrophobic inorganic compound particles are mixed in the organic solvent is not particularly limited, and is between the melting point and the boiling point of the organic solvent to be used. Any temperature is acceptable. The mixing time may be about 1 minute to 10 hours. Furthermore, although mixing can be performed by stirring using a stirring blade or the like, mechanical treatment may be combined as necessary. Examples of such mechanical processing include wet processing such as a ball mill, a bead mill, and a jet mill, and ultrasonic processing using a bath type or probe type sonicator.

The organosol of hydrophobic inorganic compound particles is preferably an organosol of hydrophobic silica particles.
An organosol of hydrophobic silica particles is a hydrophobic organosilica sol that neutralizes a dispersion composed of, for example, hydrophilic colloidal silica, a silylating agent, a hydrophobic organic solvent, water, and alcohol, and after heating and aging, the solvent is distilled and replaced. It can be obtained by a manufacturing method (Japanese Patent Laid-Open No. 11-043319).
Examples of the organosol of the hydrophobic silica particles include ethyl methyl ketone dispersed hydrophobic silica sol, toluene dispersed hydrophobic silica sol, isobutyl methyl ketone dispersed hydrophobic silica sol, ethyl acetate dispersed hydrophobic silica sol, butyl acetate dispersed hydrophobic silica sol, propylene glycol monomethyl ether Acetate-dispersed hydrophobized silica sol and the like can be mentioned.
In addition, commercially available organosols of these hydrophobic inorganic compound particles can be used as they are.

[Composite of cured amino resin particles and hydrophobic inorganic compound particles]
In the dispersion, the hydrophobic inorganic compound particles may adhere to the surface of the cured amino resin particles to form a composite. The composite is physically or electrostatically attached to the surface of the cured amino resin particles that are hydrophilic and positively charged by hydrophobic inorganic compound particles that are negatively charged in an organic solvent. , It is presumed to be composite. For this reason, it is thought that the dispersibility with respect to an organic solvent improves, aggregation of hardening amino resin particles is suppressed, and it is excellent also in redispersibility.
The composite in the present invention is obtained by mixing hydrophobic inorganic compound particles and cured amino resin particles in a non-aqueous medium (organic solvent), and is disclosed in JP-A-2002-327036. The spherical composite cured melamine resin particles are obtained by coating the surface of the melamine resin with inorganic compound particles by mixing the spherical composite cured melamine resin particles and the inorganic compound particles in an aqueous medium, and used for the production. Both are distinguished depending on the type of medium (non-aqueous / aqueous) and the presence or absence of surface treatment of inorganic compound particles.

The average particle size of the composite is approximately the same as or slightly larger than the average particle size of the cured amino resin particles used, and no significant increase in particle size due to aggregation of the cured amino resin particles is observed. Is 0.05 to 100 μm.

In addition, the dispersion liquid of the present invention can be in the form of powdery particles by drying the solid content obtained by general filtration or centrifugation, or by directly spray-drying an aqueous dispersion slurry of resin particles. . Drying is preferably performed at 50 to 250 ° C. for 0.01 to 50 hours.
In addition, when the dried powder particles are aggregated between the particles, mixers with shearing force such as homomixers, Henschel mixers, Ladige mixers, pin disc mills, pulverizers, inomizers, counter jet mills When appropriately treated by a pulverizer such as the like, it is possible to loosen the interparticle aggregation without destroying the spherical particles.

The cured amino resin particle dispersion of the present invention may contain a general-purpose synthetic resin that is soluble in the organic solvent.
Examples of general-purpose synthetic resins include polyolefin resins such as PE (polyethylene), PP (polypropylene), EVA (ethylene-vinyl acetate copolymer), EEA (ethylene-ethyl acrylate copolymer); PS (polystyrene) Polystyrene resins such as HIPS (high impact polystyrene), AS (acrylonitrile-styrene copolymer), ABS (acrylonitrile-butadiene-styrene copolymer), MS (methyl methacrylate-styrene copolymer); polycarbonate resin; Polyvinyl resin; Polyamide resin; (Meth) acrylic resin such as PMMA (polymethyl methacrylate); PET (polyethylene terephthalate), polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, P Polyester resin such as A (polylactic acid), poly-3-hydroxybutyric acid, polycaprolactone, polybutylene succinate, polyethylene succinate / adipate; polyphenylene ether resin; modified polyphenylene ether resin; polyacetal resin; polysulfone resin; Polyvinyl alcohol resin; polyglycolic acid; modified starch; cellulose acetate, cellulose triacetate; chitin, chitosan; thermoplastic resins such as lignin, and thermosetting resins such as phenol resin, unsaturated polyester resin, polyurethane resin, epoxy resin Is mentioned.
In addition, these general-purpose synthetic resins that are soluble in organic solvents may be included in the form of high molecular weight that has already been polymerized, or may be included in the form of reactive monomers or oligomers that are polymerizable, and then polymerized. It may be in the form of a high molecular weight. Furthermore, when the above-mentioned polymerizable monomer or oligomer can take a liquid form, these may be used as a dispersion medium instead of the organic solvent.

The cured amino resin particle dispersion of the present invention may contain other particles (inorganic particles and / or organic particles) having a large average particle size in addition to the hydrophobic inorganic compound particles used for the purpose of improving dispersibility. Examples of such inorganic particles are the same as those described above. Examples of such organic particles include general-purpose synthetic resin particles, and more specifically, acrylic resin particles, polystyrene resin particles, and the like. These other particles have a primary particle diameter larger than 1/5 of the average particle diameter of the cured amino resin particles. When other particles are included, the amount is preferably 1 to 100,000 parts by weight, particularly 50 to 1,000 parts by weight, based on 100 parts by weight of the cured amino resin particles.

The dispersion liquid of the present invention described above is formed on a suitable substrate such as PET, glass, ITO, etc. by spin coating, dipping, flow coating, ink jet, spraying, bar coating, gravure coating, slitting. It can be suitably used for the preparation of coating solutions for coating by the coating method, slit die coating method, roll coating method, transfer printing method, brush coating, blade coating method, air knife coating method, etc. Thus, a thin film composite in which the cured amino resin particles are easily dispersed uniformly can be obtained.
Such thin film composites take advantage of the high refractive index, water resistance, solvent resistance, and heat resistance of cured amino resin particles, making use of various abrasive materials, matte materials, wear resistant materials, light diffusion sheets, touch panels. Hard coat, gas adsorbent, acidic substance adsorbent, solar cell electrode, photocatalyst for water splitting, optical material, magnetic material, conductive material, flame retardant material, papermaking material, fiber treatment material, etc. The

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following description.

In the following examples, the apparatus and conditions used for the analysis are as follows.
Laser diffraction / scattering particle size distribution measurement apparatus name: Mastersizer (registered trademark) 2000 [Malvern Instruments, Inc.]
Sample dispersion unit: Hydro 2000 μP (Malvern Instruments)
Particle refractive index: 1.65
Solvent refractive index: Toluene 1.490
Carbon tetrachloride 1.459
Xylene 1.498
MEK 1.377
Stirring: 1,000 rpm
Measurement: Sample input is 0 minutes, 10 minutes every minute (11 consecutive measurements)
Analysis model: Single narrow mode (spherical)

Abbreviations of samples used in the following examples are as follows.
OB20: Optobead (registered trademark) 2000M [manufactured by Nissan Chemical Industries, Ltd., average particle size: 2.0 μm]
OB35: Optobeads (registered trademark) 3500M [Nissan Chemical Industry Co., Ltd., average particle size: 3.5 μm]
OB65: Opto beads (registered trademark) 6500M [manufactured by Nissan Chemical Industries, Ltd., average particle size: 6.5 μm]
OB105: Opto beads (registered trademark) 10500M [manufactured by Nissan Chemical Industries, Ltd., average particle size: 10.5 μm]
MX500: Chemisnow MX-500 [manufactured by Soken Chemical Co., Ltd., average particle size: 5.0 μm, particle refractive index: 1.49]
SX350: Chemisnow SX-350 [manufactured by Soken Chemical Co., Ltd., average particle size: 3.5 μm, particle refractive index: 1.59]
MEK-ST: Organosilica sol MEK-ST [manufactured by Nissan Chemical Industries, Ltd., silica average particle size: 10-15 nm, 30% by mass MEK sol]
TOL-ST: Organosilica sol TOL-ST [manufactured by Nissan Chemical Industries, Ltd., silica average particle size: 10-15 nm, 40 mass% toluene sol]
MIBK-ST: Organosilica sol MIBK-ST [manufactured by Nissan Chemical Industries, Ltd., silica average particle size: 10-15 nm, 30 mass% MIBK sol]
MEK-ST-L: Organosilica sol MEK-ST-L [manufactured by Nissan Chemical Industries, Ltd., silica average particle size: 40-50 nm, 30% by mass MEK sol]
MEK: ethyl methyl ketone MIBK: isobutyl methyl ketone

[Example 1]
In a 100 mL reaction flask equipped with a stirrer and a half-moon shaped stirring blade (blade width 50 × height 19 × thickness 3 [mm]), 3.0 g of OB65 as cured amino resin particles and MEK-ST0 as hydrophobic inorganic compound particles .33 g (3 parts by mass in terms of solid content with respect to 100 parts by mass of the cured amino resin particles) and 5.79 g of toluene as a dispersion medium (the total amount of the solvent including the solvent in the hydrophobic inorganic compound particle sol is the cured amino resin particles 200 parts by mass with respect to 100 parts by mass). This mixture was stirred at 280 rpm for 1 hour at room temperature (approximately 25 ° C.) to prepare a cured amino resin particle dispersion.

[Example 2]
The same operation as in Example 1 was carried out except that the hydrophobic inorganic compound particles were changed to MEK-ST 0.06 g (0.6 parts by mass) and the dispersion medium was changed to 5.96 g of toluene (200 parts by mass), respectively. A cured amino resin particle dispersion was prepared.

[Example 3]
The cured amino acid was treated in the same manner as in Example 1 except that the hydrophobic inorganic compound particles were changed to MEK-ST 1.0 g (10 parts by mass) and the dispersion medium was changed to 5.30 g of toluene (200 parts by mass). A resin particle dispersion was prepared.

[Example 4]
The same operation as in Example 1, except that the hydrophobic inorganic compound particles were changed to 0.05 g (0.7 parts by mass) of TOL-ST, and the dispersion medium was changed to 5.98 g (200 parts by mass) of toluene, respectively. A cured amino resin particle dispersion was prepared.

[Example 5]
Except that the hydrophobic inorganic compound particles were changed to 0.11 g (1 part by mass) of TOL-ST and the dispersion medium was changed to 5.95 g (200 parts by mass) of toluene, respectively, the same procedure was followed as in Example 1 to obtain a cured amino acid. A resin particle dispersion was prepared.

[Example 6]
The cured amino acid was treated in the same manner as in Example 1 except that the hydrophobic inorganic compound particles were changed to TOL-ST 0.30 g (4 parts by mass) and the dispersion medium was changed to 5.82 g of toluene (200 parts by mass). A resin particle dispersion was prepared.

[Example 7]
Except that the hydrophobic inorganic compound particles were changed to 1.0 g (13 parts by mass) of TOL-ST and the dispersion medium was changed to 5.41 g (200 parts by mass) of toluene, respectively, the same procedure as in Example 1 was carried out. A resin particle dispersion was prepared.

[Example 8]
The procedure was the same as in Example 1 except that the hydrophobic inorganic compound particles were changed to 10 g TOL-ST (130 parts by mass) and no dispersion medium was added (200 parts by mass with the solvent in the hydrophobic inorganic compound particle sol). Then, a cured amino resin particle dispersion was prepared.

[Example 9]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the hydrophobic inorganic compound particles were changed to 0.31 g (3 parts by mass) of MIBK-ST.

[Example 10]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the hydrophobic inorganic compound particles were changed to 0.30 g (3 parts by mass) of MEK-ST-L.

[Comparative Example 1]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the dispersion medium was changed to 6.00 g (200 parts by mass) of toluene without adding the hydrophobic inorganic compound particles.

[Evaluation of Dispersibility of Cured Amino Resin Particle Dispersion-1]
The dispersibility of the cured amino resin particle dispersions obtained in Examples 1 to 10 and Comparative Example 1 was evaluated by laser diffraction / scattering particle size distribution measurement. The measurement was performed 11 times in total for 10 minutes every minute after each dispersion sample was put into the chamber, and evaluation was performed according to the following criteria from each particle size distribution chart. The results are also shown in Table 1. In addition, FIG. 1 (Example 1) and FIG. 2 (Comparative Example 1) show particle size distribution charts of the cured amino resin particle dispersions obtained in Example 1 and Comparative Example 1 immediately after sample introduction.
<Dispersibility evaluation criteria>
A: Aggregates of 10 μm or more are never observed in all 11 measurements ○: Aggregates of 10 μm or more may be observed Δ: Aggregates of 10 μm or more are observed in all 11 measurements × : Aggregates of 10 μm or more are observed as main peaks

As shown in Table 1, while the cured amino resin particles alone cannot be dispersed uniformly in toluene (Comparative Example 1), the addition of various organosilica sols can dramatically improve the dispersibility. confirmed.

[Example 11]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the dispersion medium was changed to 5.79 g (200 parts by mass) of carbon tetrachloride.

[Example 12]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the dispersion medium was changed to 5.80 g (200 parts by mass) of xylene.

[Example 13]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the dispersion medium was changed to 5.79 g (200 parts by mass) of MEK.

[Comparative Example 2]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the dispersion medium was changed to 6.00 g (200 parts by mass) of carbon tetrachloride without adding the hydrophobic inorganic compound particles.

[Comparative Example 3]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the dispersion medium was changed to 6.00 g (200 parts by mass) of xylene without adding the hydrophobic inorganic compound particles.

[Comparative Example 4]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the dispersion medium was changed to 6.00 g (200 parts by mass) of MEK without adding the hydrophobic inorganic compound particles.

[Dispersibility evaluation of cured amino resin particle dispersion-2]
The dispersibility of the cured amino resin particle dispersions obtained in Examples 11 to 13 and Comparative Examples 2 to 4 was evaluated by the method described above. The results are also shown in Table 2.

As shown in Table 2, it was confirmed that the dispersibility was drastically improved by adding hydrophobic inorganic compound particles in a wide range of dispersion solvents.

[Example 14]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the cured amino resin particles were changed to 3.0 g of OB20.

[Example 15]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the cured amino resin particles were changed to 3.0 g of OB35.

[Example 16]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the cured amino resin particles were changed to 3.0 g of OB105.

[Comparative Example 5]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the cured amino resin particles were changed to 3.0 g of OB20 and the hydrophobic inorganic compound particles were not added.

[Comparative Example 6]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the cured amino resin particles were changed to 3.0 g of OB35 and the hydrophobic inorganic compound particles were not added.

[Comparative Example 7]
A cured amino resin particle dispersion was prepared in the same manner as in Example 1 except that the cured amino resin particles were changed to 3.0 g of OB105 and the hydrophobic inorganic compound particles were not added.

[Dispersibility evaluation of cured amino resin particle dispersion-3]
The dispersibility of the cured amino resin particle dispersions obtained in Examples 14 to 16 and Comparative Examples 5 to 7 was evaluated by the method described above. The evaluation criteria were as follows. The results are also shown in Table 3.
<Dispersibility evaluation criteria>
◎: Aggregates other than primary particles are not observed once in all 11 measurements. ○: Aggregates other than primary particles may be observed. △: Aggregates other than primary particles are observed in all 11 measurements. X: Aggregates other than primary particles are observed as main peaks

As shown in Table 3, it was confirmed that the dispersibility was dramatically improved by adding hydrophobic inorganic compound particles regardless of the average particle diameter of the cured amino resin particles.

[Example 17]
In a 100 mL reaction flask equipped with a stirrer and a half-moon shaped stirring blade (blade width 50 × height 19 × thickness 3 [mm]), 1.5 g of OB65 as cured amino resin particles and TOL-ST0 as hydrophobic inorganic compound particles .15 g (4 parts by mass in terms of solid content with respect to 100 parts by mass of the cured amino resin particles), 1.5 g of MX500 as the other particles, and 5.91 g of toluene as the dispersion medium (the solvent in the hydrophobic inorganic compound particle sol The total amount of the solvent was 400 parts by mass) with respect to 100 parts by mass of the cured amino resin particles. The mixture was stirred at room temperature (approximately 25 ° C.) at 280 rpm for 1 hour to prepare a cured amino resin particle / organic particle dispersion.

[Example 18]
Except for changing hydrophobic inorganic compound particles to 0.19 g (5 parts by mass) of TOL-ST, 1.5 g of other particles to 1.5 g of SX350, and 5.89 g of toluene (400 parts by mass of toluene). In the same manner as in Example 17, a cured amino resin particle / organic particle dispersion was prepared.

[Comparative Example 8]
A cured amino resin particle / organic particle dispersion was prepared in the same manner as in Example 17 except that the dispersion medium was changed to 6.00 g (400 parts by mass) of toluene without adding the hydrophobic inorganic compound particles. .

[Comparative Example 9]
The same operation as in Example 17 was carried out except that the hydrophobic inorganic compound particles were not added, the other particles were changed to 1.5 g of SX350, and the dispersion medium was changed to 6.00 g of toluene (400 parts by mass), respectively. A cured amino resin particle / organic particle dispersion was prepared.

[Dispersibility evaluation of cured amino resin particle dispersion-4]
The dispersibility of the cured amino resin particle / organic particle dispersions obtained in Examples 17 to 18 and Comparative Examples 8 to 9 is determined according to the method and criteria described in [Dispersibility Evaluation-3 of Cured Amino Resin Particle Dispersions] above. It was evaluated with. The results are also shown in Table 4. In addition, FIG. 3 (Example 17) and FIG. 4 (Comparative Example 8) show particle size distribution charts of the cured amino resin particle / organic particle dispersions obtained in Example 17 and Comparative Example 8 after 10 minutes from sample introduction. Shown in The particle refractive index in the laser diffraction / scattering particle size distribution measurement is 1.57 (= (1.65 + 1.49), the average value of the refractive index of OB65 (1.65) and the refractive index of MX500 (1.49). ÷ 2) (Example 17 and Comparative Example 8), average value 1.62 (= (1.65 + 1.59) ÷ 2) of the refractive index of OB65 (1.65) and the refractive index of SX350 (1.59) (Example 18 and Comparative Example 9) were employed.

As shown in Table 4, it was confirmed that even when the cured amino resin particles and other particles were used in combination, the dispersibility was dramatically improved by adding the hydrophobic inorganic compound particles.

Claims

A cured amino resin particle dispersion in which cured amino resin particles and hydrophobic inorganic compound particles are dispersed in an organic solvent.
The dispersion according to claim 1, wherein the hydrophobic inorganic compound particles adhere to the surface of the cured amino resin particles to form a composite.
The dispersion according to claim 1, wherein the hydrophobic inorganic compound particles are contained in an amount of 0.01 to 200 parts by mass with respect to 100 parts by mass of the cured amino resin particles.
The dispersion according to any one of claims 1 to 3, wherein the hydrophobic inorganic compound particles are hydrophobic silica particles.
The dispersion according to any one of claims 1 to 4, wherein the organic solvent is contained in an amount of 10 to 100,000 parts by mass with respect to 100 parts by mass of the cured amino resin particles.
A method for producing a cured amino resin particle dispersion, comprising a step of mixing cured amino resin particles and hydrophobic inorganic compound particles in an organic solvent at a temperature between the melting point and boiling point of the organic solvent.
A method for producing a cured amino resin particle dispersion, comprising a step of mixing cured amino resin particles and an organosol of hydrophobic inorganic compound particles in an organic solvent at a temperature between the melting point and boiling point of the organic solvent.
The production method according to claim 7, wherein the organosol of the hydrophobic inorganic compound particles is an organosol of hydrophobic silica particles.
The hydrophobic inorganic compound particles according to any one of claims 6 to 8, wherein the hydrophobic inorganic compound particles are used in an amount of 0.01 to 200 parts by mass with respect to 100 parts by mass of the cured amino resin particles. Production method.