JP2007100082A - Colored composite micro-particle powder and dispersion containing the same colored composite micro-particle powder and method for producing colored composite micro-particle powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide colored composite micro-particle powder having an ultrafine primary particle diameter, high tinting power and excellent dispersibility and light resistance and to provide a dispersion containing the colored composite micro-particle powder and having excellent dispersibility. <P>SOLUTION: The colored composite micro-particle powder composed of composite micro-particles encapsulating silica in an organic pigment can be obtained as follows. Silica particles and a surface modifier are mixed and stirred to coat the particle surfaces of the silica particles with the surface modifier. The organic pigment is then added and the resultant mixture is mixed and stirred to afford composite particles in which the organic pigment sticks to the particle surfaces of the silica particles coated with the surface modifier. Part of the silica particles and the surface modifier in the composite particles are then dissolved with an alkali solution. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a colored fine composite particle powder having a small primary particle size, high coloring power, excellent dispersibility, and excellent light resistance, and dispersibility containing the colored composite particle powder. It provides an excellent dispersion.

  Organic pigments are widely used as coloring materials such as paints, resins, printing inks, inkjet inks, toners, and color filters. In general, high coloring power is required for these applications, and it is known that it is effective to make the pigment finer for this purpose.

  However, organic pigments form fine primary particles of about 20 nm to 100 nm from a pigment in a molecular state by a chemical reaction or the like. However, in this state, the surface energy of the particles is very high, and thus aggregation tends to occur. In particular, it is known to form secondary particles having a large particle size and a strong cohesive force, and a technique for refining the pigment is required.

  At present, as a method for refining organic pigments, a solvent salt milling method and a dry pulverization method are generally known and widely used.

  The solvent salt milling method is a method of mechanically pulverizing the pigment particles together with a highly viscous water-soluble organic solvent such as polyethylene glycol using a grinding agent such as sodium chloride, and the dry pulverization method. In this method, fine pigment particles are obtained by dry-pulverizing coarse pigment particles using a pulverizer such as a ball mill, an attritor, and a vibration mill. The cohesive force between the pigment particles also becomes strong, and it is extremely difficult to maintain the shape of the primary particles. As a result, the pigment particles exist as secondary aggregates aggregated in an aggregate state.

  In addition, paints and printed materials using these organic pigments are used outdoors and may be directly exposed to sunlight or wind and rain, and thus are required to have excellent light resistance. However, since the tendency to inferior light resistance becomes stronger as the miniaturization progresses, it has been difficult to obtain characteristics that achieve both the finer pigment and excellent light resistance.

  So far, a production method (Patent Document 1) has been proposed in which a crude quinophthalone pigment or isoindoline pigment having an average particle diameter of more than 100 nm is finely divided by adding a small amount of an organic solvent having a crystal growth action and dry pulverizing. ing.

  Moreover, as a coloring material that is fine and excellent in light resistance, an organic-inorganic composite pigment (Patent Document 2) in which an organic pigment is attached to the surface of white inorganic particles through a paste such as alkoxysilane has been proposed.

  In addition, as a fine colorant having excellent transparency, the entire amount of white inorganic particles as core particles can be dissolved in composite particles in which organic pigments are attached to the surface of white inorganic particles via a paste material such as alkoxysilane. There has been proposed a colored fine particle powder (Patent Document 3) in which core particles are completely dissolved and removed using an acid or alkali equal to or more than a theoretical value.

JP 2005-36150 A JP 2002-356625 A JP 2003-246941 A

  A fine colorant having a small primary particle diameter, high coloring power and excellent light resistance is currently most demanded. However, in order to obtain a high coloring power, it is necessary to make the pigment fine. However, since the light resistance tends to decrease as the particle diameter of the pigment decreases, a colorant that satisfies these contradicting characteristics is: It has not been obtained yet.

  That is, Patent Document 1 describes a method of finely pulverizing a crude quinophthalone pigment or isoindoline pigment having an average particle diameter of more than 100 nm by adding a small amount of an organic solvent having a crystal growth action and dry pulverizing. However, as shown in the following comparative example, the organic pigment is simply refined, and the ζ potential of the obtained organic pigment is close to zero, so that it is difficult to obtain an electrostatic repulsion effect in the vehicle, and therefore It is difficult to obtain good dispersibility and dispersion stability in the vehicle.

  Patent Document 2 describes a method of attaching an organic pigment to the surface of white inorganic particles through an adhesive such as alkoxysilane. As shown in a comparative example, silica particles are used as core particles. Therefore, it is difficult to easily obtain a coloring power equal to or higher than that of the raw material organic pigment to be adhered.

  Further, Patent Document 3 discloses a theoretical value equal to or more than the theoretical value that can dissolve all of the white inorganic particles as the core particles with respect to the composite particles in which the organic pigment is adhered to the surface of the white inorganic particles through a paste material such as alkoxysilane. The method of completely dissolving and removing the core particles using an acid or alkali to leave the organic pigment is described. However, as shown in the comparative example, the organic pigment is used because the acid or alkali is used in an amount equal to or more than the theoretical value. It is difficult to obtain a colorant with good light resistance. In addition, since silica is completely dissolved and removed, the ζ potential is close to zero, and it is difficult to obtain an electrostatic repulsion effect in the vehicle. Therefore, it is difficult to obtain good dispersibility and dispersion stability in the vehicle. Become.

  In view of the above, an object of the present invention is to provide a colored fine particle powder having a small primary particle size, high coloring power, excellent dispersibility, and excellent light resistance.

  The technical problem can be achieved by the present invention as follows.

  That is, the present invention is a colored fine composite particle powder characterized by being fine composite particles in which silica is encapsulated in an organic pigment (Invention 1).

  Further, according to the present invention, the colored microcomposite according to the present invention is characterized in that the silica contained in the microcomposite particles is 0.001 to 9% by weight in terms of Si with respect to the colored microcomposite particle powder. Particle powder. (Invention 2).

  In addition, the present invention is a dispersion obtained by dispersing the colored microcomposite particle powder according to the present invention 1 or the present invention 2 in a solvent (the present invention 3).

  The present invention also provides an aqueous dispersion characterized in that the solvent described in the present invention 3 is water and / or a water-soluble organic solvent (invention 4).

  Further, the present invention is a solvent-based dispersion characterized in that the solvent described in the present invention 3 is an organic solvent (Invention 5).

  In the present invention, the silica particles and the surface modifier are mixed and stirred, and the surface of the silica particles is coated with the surface modifier. Then, an organic pigment is added, mixed and stirred, and the surface modifier is mixed. After obtaining composite particles in which an organic pigment is adhered to the surface of the coated silica particles, the silica particles and a part of the surface modifier in the composite particles are dissolved using an alkaline solution. This is a method for producing colored fine composite particle powder according to Invention 1 or Invention 2 (Invention 6).

  The colored fine composite particle powder according to the present invention has high coloring power and is excellent in dispersibility and light resistance, and thus is suitable as a coloring material for various applications.

  Since the dispersion according to the present invention uses the colored fine composite particle powder having the above-mentioned properties as a coloring material, it is suitable as a dispersion for various uses.

  The colored fine composite particle powder according to the present invention will be described below.

  The colored fine composite particle powder according to the present invention comprises fine composite particles in which silica is encapsulated in an organic pigment.

  The amount of silica contained in the colored fine composite particle powder according to the present invention is 0.001 to 9.0% by weight, more preferably 0.005 to 7.0, based on the colored fine composite particle powder in terms of Si. % By weight, most preferably 0.01-5.0% by weight. When the amount of silica is less than 0.001% by weight with respect to the colored microcomposite particles in terms of Si, the amount of silica contained in the colored microcomposite particle powder is too small, so that the ζ potential of the colored microcomposite particle powder is almost equal. Since the electrostatic repulsion effect is not obtained, the dispersibility in the vehicle is deteriorated. Moreover, since there is almost no silica, it is difficult to obtain sufficient light resistance. On the other hand, when it exceeds 9.0% by weight, it is difficult to obtain sufficient coloring power because the amount of silica contained in the colored fine composite particle powder is too large.

  The average primary particle diameter of the colored fine composite particle powder according to the present invention is preferably 1 to 50 nm, more preferably 1 to 40 nm, and most preferably 1 to 30 nm.

  The number-converted average particle diameter of the colored fine composite particle powder according to the present invention is preferably 200 nm or less, more preferably 1 to 150 nm, still more preferably 1 to 100 nm, and most preferably 1 to 50 nm. When the number converted average particle diameter of the colored fine composite particle powder exceeds 200 nm, the particle size is too large, which is not preferable.

  The volume-converted average particle diameter of the colored fine composite particle powder according to the present invention is preferably 200 nm or less, more preferably 1 to 150 nm, and most preferably 1 to 100 nm. When the volume-converted average particle diameter of the colored fine composite particle powder exceeds 200 nm, the particle size is too large, which is not preferable.

BET specific surface area of the colored fine composite particles according to the present invention is preferably from 20 to 500 m ² / g, more preferably 25~400m ² / g, still more preferably 30~300m ² / g.

  The coloring power of the colored fine composite particle powder according to the present invention is preferably 102% or more, more preferably 103% or more, and still more preferably 104% or more, according to the evaluation method described later.

The light resistance of the colored microcomposite particle powder according to the present invention is preferably 5.0 or less, more preferably 4.5 or less, and still more preferably 4.0 in terms of ΔE ^* value in the evaluation method described later. It is as follows.

  The ζ potential of the colored microcomposite particle powder according to the present invention is preferably −5 mV or less, more preferably −8 mV or less, and further preferably −10 mV or less when measured in an aqueous system. When the ζ potential when measured in an aqueous system is closer to zero than −5 mV, it is difficult to obtain good dispersibility and dispersion stability due to the electrostatic repulsion effect.

  When the ζ potential is measured in a solvent system, it is preferably −2 mV or less, more preferably −3 mV or less, and still more preferably −5 mV or less. When the ζ potential when measured in a solvent system is closer to zero than −2 mV, it is difficult to obtain good dispersibility due to the electrostatic repulsion effect.

  Next, a dispersion containing the colored fine composite particle powder according to the present invention will be described.

  The dispersion according to the present invention includes both an aqueous dispersion containing water and / or a water-soluble organic solvent as a main solvent and a solvent-based dispersion containing an organic solvent as a main solvent. It can be obtained by dispersing the colored fine composite particle powder according to the present invention.

  The dispersion according to the present invention contains 3 to 300 parts by weight, preferably 4 to 150 parts by weight, more preferably 5 to 5 parts by weight of the colored fine composite particle powder according to the present invention with respect to 100 parts by weight of the dispersion-constituting substrate. 100 parts by weight, still more preferably 5 to 75 parts by weight, most preferably 5 to 50 parts by weight. The constituent substrate of the dispersion is a solvent such as water, a water-soluble organic solvent, an organic solvent, etc., and if necessary, resin, antifoaming agent, extender pigment, drying accelerator, surfactant, curing accelerator, assistant. An agent or the like is blended.

  Solvents for aqueous dispersions include water and aqueous solvents such as ethyl alcohol, propyl alcohol, and butyl alcohol, and glycol ether solvents such as methyl cellosolve, ethyl cellosolve, propyl cellosolve, and butyl cellosolve. Oxyethylene or oxypropylene addition polymer such as diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, alkylene glycol such as ethylene glycol, propylene glycol, 1,2,6-hexanetriol, It can be used by mixing with water-soluble organic solvents such as glycerin and 2-pyrrolidone.

  Solvents for solvent-based dispersions include aromatic hydrocarbons such as toluene and xylene; ketones such as methyl ethyl ketone and cyclohexanone; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone Ether ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether Ether acetates such as acetate and propylene glycol monoethyl ether acetate; ethyl acetate and vinegar Butyl acetate esters such as isobutyl acetate; methyl lactate ester, ethyl lactate esters, lactate esters such as lactic acid propyl ester, ethylene carbonate, propylene carbonate, and cyclic esters such as γ- butyrolactone. In particular, an electrostatic repulsion effect can be effectively obtained by using a highly polar organic solvent represented by alcohols, ether alcohols and ether acetates. These solvents can be used alone or in combination of two or more.

  The number conversion average particle size of the dispersion according to the present invention is preferably 1 to 200 nm, more preferably 1 to 150 nm, still more preferably 1 to 100 nm, and most preferably 1 to 50 nm. When the number-converted dispersed particle diameter exceeds 200 nm, the particle size increases, which is not preferable.

  1-200 nm is preferable, as for the volume conversion dispersion | distribution average particle diameter of the dispersion concerning this invention, More preferably, it is 1-150 nm, More preferably, it is 1-100 nm. When the volume-converted dispersed particle diameter exceeds 200 nm, the particle size increases, which is not preferable.

  The dispersion stability of the dispersion according to the present invention is preferably 3, 4, or 5, more preferably 4 or 5, when the degree of sedimentation of the particle powder is visually evaluated in the evaluation method described later. . Further, the change rate of the viscosity is preferably 20% or less, more preferably 10% or less. When the degree of sedimentation of the particle powder is evaluated visually, it becomes 1 or 2, or when the rate of change in viscosity is more than 20%, it becomes difficult to store for a long time in a stable dispersion state.

The specific extinction coefficient ε _w (weight basis) representing the coloring power of the dispersion according to the present invention is preferably 1.20 or more, more preferably 1.40 to 5.00, by an evaluation method described later. More preferably, it is 1.50-5.00.

  Next, a method for producing colored fine composite particle powder according to the present invention will be described.

  The colored micro composite particles according to the present invention are prepared by mixing and stirring silica particles as a core particle and a surface modifier, coating the surface modifier on the surface of the silica particles, adding an organic pigment, and mixing and stirring. Thus, after obtaining composite particles in which an organic pigment is adhered to the surface of the silica particles coated with the surface modifier, one of the silica particles and the surface modifier in the composite particles is obtained using an alkaline solution. It can be obtained by dissolving the part.

  The average primary particle diameter of the silica particles in the present invention is preferably 1 to 100 nm, more preferably 1 to 50 nm, and most preferably 1 to 30 nm.

BET specific surface area value of the silica particles in the invention is preferably from 10 to 1000 m ² / g, more preferably 15~500m ² / g.

  As the surface modifier in the present invention, anything may be used as long as an organic pigment can be attached to the surface of the silica particles, and an organosilicon compound such as alkoxysilane, silane coupling agent and organopolysiloxane, Coupling agents such as titanate-based, aluminate-based and zirconate-based, low-molecular or high-molecular surfactants and the like are preferably used. More preferred are organosilane compounds such as alkoxysilanes, silane coupling agents and organopolysiloxanes.

  Examples of organosilicon compounds include methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, ethyltriethoxysilane, and propyl. Alkoxysilanes such as triethoxysilane, butyltriethoxysilane, isobutyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane and decyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-aminopropyltriethoxysilane , Γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloyloxypropyltrime Silane coupling agents such as xylsilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, polysiloxane, methylhydrogen And organopolysiloxanes such as polysiloxane and modified polysiloxane.

  Titanate coupling agents include isopropyl tristearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethylaminoethyl) titanate, tetraoctyl bis (ditridecyl phosphate titanate, tetra (2,2 diallyl) Examples include oxymethyl-1-butyl) bis (ditridecyl) phosphate titanate, bis (dioctylpyrophosphate) oxyacetate titanate, and bis (dioctylpyrophosphate) ethylene titanate.

  Examples of the aluminate coupling agent include acetoalkoxy aluminum diisopropylate, aluminum diisopropoxy monoethyl acetoacetate, aluminum trisethyl acetoacetate, aluminum trisacetylacetonate and the like.

  Examples of the zirconate coupling agent include zirconium tetrakisacetylacetonate, zirconium dibutoxybisacetylacetonate, zirconium tetrakisethylacetoacetate, zirconium tribotoxymonoethylacetoacetate, zirconium tributoxyacetylacetonate and the like.

  Examples of the low molecular surfactant include alkylbenzene sulfonate, dioctyl sulfone succinate, alkylamine acetate, alkyl fatty acid salt and the like. Examples of the polymeric surfactant include polyvinyl alcohol, polyacrylate, carboxymethylcellulose, acrylic acid-maleate copolymer, and olefin-maleate copolymer.

  The coating amount of the surface modifier is preferably 0.05 to 15.0% by weight, more preferably 0.1 to 12.0% by weight, and still more preferably, in terms of C with respect to the silica particles as the core particles. 0.15 to 10.0% by weight. By setting it as 0.05-15 weight%, 10-500 weight part of organic pigments can be made to adhere with respect to 100 weight part of silica particles.

  The organic pigment in the present invention is generally a red organic pigment, a blue organic pigment, a yellow organic pigment, a green organic pigment, which is used as a coloring material for paints, resins, printing inks, inkjet inks, toners, color filters and the like. Various organic pigment particle powders such as organic organic pigments, orange organic pigments, brown organic pigments, purple organic pigments, and black organic pigments can be used. However, organic pigments with weak alkali resistance, such as alkali blue and isoindoline organic pigments, are used in the present invention because the organic pigment contained in the composite particles dissolves when the silica particles are alkali-dissolved by the method described below. It is not preferable to use it for producing colored fine composite particle powder according to the above.

  Among various organic pigments, red organic pigments include azo pigments such as brilliant carmine, permanent red, and condensed azo red, and diaminoanthraquinonyl red, quinacridone red, thioindigo red, perylene red, perinone red, and diketopyrrolopyrrole. A condensed polycyclic pigment such as red can be used. As the blue organic pigment, phthalocyanine pigments such as metal-free phthalocyanine blue, phthalocyanine blue and fast sky blue, and condensed polycyclic pigments such as indanthrone blue and indigo blue can be used. As yellow organic pigments, azo pigments such as Hansa Yellow, Benzidine Yellow, Permanent Yellow, and condensed azo yellow, and condensed polycyclic pigments such as isoindolinone yellow, anthrapyrimidine yellow, and quinophthalone yellow can be used. As the green organic pigment, a phthalocyanine pigment such as phthalocyanine green can be used. As the orange organic pigment, azo pigments such as permanent orange, resol fast orange, pyrazolone orange, and vulcan orange, and condensed polycyclic pigments such as quinacridone, perinone orange, and diketopyrrolopyrrole orange can be used. As the brown organic pigment, azo pigments such as permanent brown, para brown and benzimidazolone brown and condensed polycyclic pigments such as thioindigo brown can be used. As the purple organic pigment, azo pigments such as fast violet and condensed polycyclic pigments such as unsubstituted quinacridone, dioxazine violet and perylene violet can be used. As the black organic pigment, condensed polycyclic pigments such as perylene black and aniline black can be used. The organic pigment used in the invention is not limited to the pigments exemplified above.

  The addition amount of the organic pigment is 10 to 500 parts by weight, preferably 30 to 400 parts by weight, and more preferably 50 to 300 parts by weight with respect to 100 parts by weight of the silica particles as the core particles.

  In the composite particles in the present invention, silica particles and a surface modifier are mixed, the surface of the silica particles is coated with the surface modifier, and then the silica coated with the surface modifier and the organic pigment are mixed. Can be obtained. Almost all of the added surface modifier is coated on the silica surface.

  As a device for mixing and stirring silica particles and a surface modifier, and mixing and stirring organic pigments and silica particles whose surface is coated with a surface modifier, a shear force can be applied to the powder layer. An apparatus is preferable, and in particular, an apparatus capable of simultaneously performing shearing, spatula and compression, for example, a wheel-type kneader, a ball-type kneader, a blade-type kneader, a roll-type kneader can be used, The mold kneader can be used more effectively.

  Examples of the wheel type kneader include edge runners (synonymous with “mix muller”, “simpson mill”, “sand mill”), multi-mal, stotz mill, wet pan mill, conner mill, ring muller, etc. Are edge runners, multi-mals, stocks mills, wet pan mills, ring mullers, more preferably edge runners. Examples of the ball kneader include a vibration mill. Examples of the blade-type kneader include a Henschel mixer, a planetary mixer, and a nauter mixer. Examples of the roll-type kneader include an extruder.

  After the surface of the silica particles is coated with a surface modifier, an organic pigment is added, mixed and stirred to adhere the organic pigment to the surface of the surface modifier-coated silica particles. The organic pigment is added little by little while taking a time of about 5 minutes to 24 hours, preferably about 5 minutes to 20 hours, or 5 to 25 parts by weight of the organic pigment with respect to 100 parts by weight of silica particles, It is preferable to divide and add until a desired addition amount is obtained.

  After attaching the organic pigment to the surface modifier-coated silica particle surface, if necessary, drying or heat treatment may be performed. In the case of performing drying or heat treatment, the heating temperature is usually preferably 40 to 150 ° C, more preferably 60 to 120 ° C, and the heating time is preferably 10 minutes to 12 hours, more preferably 30 minutes to 3 hours. preferable.

  In the case of performing drying or heat treatment, the heating temperature is usually preferably 40 to 150 ° C, more preferably 60 to 120 ° C, and the heating time is preferably 10 minutes to 12 hours, more preferably 30 minutes to 3 hours. preferable.

  The average particle diameter of the primary particles of the obtained composite particles is 1 to 100 nm, more preferably 1 to 50 nm, and still more preferably 1 to 30 nm.

BET specific surface area value of the composite particles is preferably from 10 to 500 m ² / g, more preferably 15~400m ² / g, still more preferably 20 to 300 m ² / g.

  The degree of detachment of the organic pigment from the composite particles is preferably 4 or 3 and more preferably 4 in visual observation in the later evaluation method. If the degree of desorption of the organic pigment is 2 or less, the desorbed organic pigment remains coarsened by recrystallization or agglomeration, etc., and is mixed in the colored fine composite particle powder as the final product. It is not preferable.

  The colored microcomposite particle powder according to the present invention is obtained by treating the composite particles with an alkali and dissolving silica or silica and a surface modifier so that a part of the silica component remains.

  As the alkali used for dissolution, an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, ammonia, or the like can be used.

  The composite particle concentration in the solution at the time of the dissolution treatment is preferably 1.0 to 30.0 parts by weight, more preferably 2.5 to 25.0 parts by weight, still more preferably 5. 0 to 20.0 parts by weight.

  The alkali amount of the solution when the silica particles in the composite particles or the silica particles and the surface modifier are dissolved is 0 of the alkali amount necessary for dissolving the silica particles or the silica particles and the surface modifier in its entirety. 0.01 to 0.95 times are preferable, 0.02 to 0.90 times are more preferable, and 0.05 to 0.85 times are more preferable. When treated with an alkali amount exceeding 0.95 times, the silica particles or the silica particles and the surface modifier are completely dissolved, so that the colored fine composite particle powder intended by the present invention cannot be obtained. When the amount of alkali is less than 0.01 times, it is industrial because it takes a very long time to dissolve silica particles or silica particles and a surface modifier to 9% by weight or less with respect to colored fine composite particle powder. It is not preferable.

  The pH when the silica particles in the composite particles or the silica particles and the surface modifier are dissolved is preferably 10.0 to 13.8, more preferably 11.0 to 13.6, and still more preferably 11. .5 to 13.4. When the pH exceeds 13.8, damage to the organic pigment due to alkali increases, and it is difficult to obtain colored fine composite particle powder having good light resistance. When the pH is less than 10.0, the silica particles or the silica particles and the surface modifier in the composite particles have a very long time to dissolve to 9% by weight or less with respect to the colored micro composite particle powder. Industrially unfavorable.

  40-100 degreeC is preferable, as for the process temperature at the time of performing a melt | dissolution process, More preferably, it is 45-90 degreeC, More preferably, it is 50-80 degreeC. When the temperature is lower than 40 ° C., it takes a long time exceeding 50 hours to dissolve the silica, which is industrially disadvantageous. When the temperature exceeds 100 ° C., it is difficult to obtain colored fine composite particle powder having good light resistance due to damage to the organic pigment, and an apparatus such as an autoclave is required, which is not industrially preferable.

  The treatment time for performing the dissolution treatment is preferably 5 minutes to 50 hours, more preferably 10 minutes to 30 hours, and even more preferably 20 minutes to 10 hours. When the treatment time is longer than 50 hours, it is industrially unfavorable because it takes a long time for the dissolution treatment.

  After the dissolution treatment, the solid content and the solution can be separated by filtration, washed, and then taken out using a normal drying or freeze-drying method. The colored fine composite particle powder obtained in the present invention can be easily dispersed due to the electrostatic repulsion effect of silica or silica and a surface modifier even when subjected to normal drying.

  Next, a method for producing the dispersion according to the present invention will be described.

  Among the dispersions according to the present invention, the aqueous dispersion is obtained by re-dispersing the obtained fine composite particle powder in water or water and a water-soluble organic solvent, or after the dissolution treatment, the solid content and the solution are filtered. Alternatively, after washing with water, the solid content taken out without drying can be obtained by dispersing it in water or a water-soluble organic solvent. If necessary, a resin, a dispersant, an antifoaming agent, a surfactant, or the like can be added as an additive.

  Among the dispersions according to the present invention, the solvent-based dispersion is obtained by redispersing the obtained fine composite particle powder in an organic solvent or an oil-based vehicle, or, after the dissolution treatment, the solid content and the solution are separated by filtration, The solid content washed with water can be obtained by flushing with an organic solvent or oil-based vehicle and then dispersing in the organic solvent or oil-based vehicle. If necessary, a resin, a dispersant, an antifoaming agent, a surfactant, or the like can be added as an additive.

  For mixing / dispersing the colored fine composite particle powder and the solvent, a ball mill, a bead mill, a sand mill, an edge runner, an ultrasonic disperser, a two or three roll mill, an extruder, a high-speed impact mill, or the like can be used. Depending on the mill material, steel beads, glass beads, ceramic beads, etc. can be used as grinding media used in grinding mills such as ball mills and bead mills, and the size ranges from 0.01 to 10 mm. A range of 0.03 to 3 mm is more preferable. The grinding temperature is not particularly limited, and may be any range from room temperature to the boiling point of the solvent used.

  The colored microcomposite particle powder according to the present invention can be used as a coloring material for various purposes, regardless of whether it is water-based or solvent-based, such as commonly used paints and printing inks.

<Action>
In the present invention, the most important point is that the colored fine composite particle powder according to the present invention has fine primary particles, high coloring power, excellent dispersibility, and excellent light resistance. That is the fact.

  Regarding the reason why the colored fine composite particle powder according to the present invention has high coloring power and excellent dispersibility, in general, an organic pigment which is simply made finer has a very high surface energy of particles, and thus is likely to cause aggregation in the vehicle. In the colored fine composite particle powder according to the present invention, the absolute value of the ζ potential increases because of the inclusion of silica in the organic pigment, and electrostatic repulsion occurs in the vehicle. The present inventor presumes that the effect was obtained, the fine dispersion could be achieved even in the vehicle, and a high coloring power could be obtained.

  Hereinafter, the present invention will be described in detail with reference to examples.

  The average particle size of the primary particles of each particle powder was measured by measuring the particle size of 350 particles shown in the electron micrographs, and the average value was shown.

  The number-average particle size and the volume-average particle size of each particle powder are determined by dispersing an aqueous solution obtained by mixing the particle powder to be measured and water for 1 minute using an ultrasonic disperser, It was measured using a system particle size analyzer FPAR-1000 "(Otsuka Electronics Co., Ltd.).

  The specific surface area value was indicated by a value measured by the BET method.

  The coating amount of the surface modifier coated on the particle surface of the silica particles and the coating amount of the organic pigment adhering to the composite particle powder are “Horiba Metal Carbon / Sulfur Analyzer EMIA-2200 Model” (Horiba Co., Ltd.). It was determined by measuring the amount of carbon using a manufacturer).

  The amount of silica encapsulated in the colored fine composite particle powder was measured using a “fluorescence X-ray analyzer 3063M type” (manufactured by Rigaku Denki Kogyo Co., Ltd.) in accordance with “General X-ray fluorescence analysis rules” of JIS K 0119.

  The ζ potential of the colored fine composite particle powder is adjusted so that the colored fine composite particle powder has a concentration of 0.5 g / l using ion-exchanged water in the case of an aqueous system and PGMEA (propylene glycol monomethyl ether acetate) in the case of a solvent system. After preparing and dispersing for 3 minutes using an ultrasonic disperser, measurement was performed by electrophoresis using “Model 501” (manufactured by PEN KEN).

The hue of each particle powder is 0.5 g of a sample and 0.5 ml of castor oil, kneaded with a Hoover-type Mahler to form a paste. To this paste, 4.5 g of clear lacquer is added, kneaded and coated to form 150 μm on cast coated paper. An application piece (coating thickness: about 30 μm) applied using a (6 mil) applicator is prepared and measured using a “spectral colorimeter CM-3610d” (manufactured by Minolta Co., Ltd.). The color index is shown according to the definition. The C ^* value represents saturation and can be obtained according to the following formula 1.

<Equation 1>
C ^* value = ((a ^* value) ² + (b ^* value) ² ) ^1/2

The coloring power of each particle powder is as follows. First, each of the primary color enamel and the color development enamel prepared according to the method described below is applied onto a cast coated paper using a 150 μm (6 mil) applicator to prepare a coated piece. The L ^* value was measured using a colorimeter CM-3610d (manufactured by Minolta Co., Ltd.), and the difference was taken as the ΔL ^* value.

Next, using the organic pigment used when preparing the colored microcomposite particle powder as a standard sample of the colored microcomposite particle powder, an application piece of primary color enamel and color-enameled enamel is prepared in the same manner as above, and each application The L ^* value of the piece was measured and the difference was taken as the ΔLs ^* value.

The value calculated according to the following equation 2 using DerutaLs ^* value of [Delta] L ^* value and the standard sample of the resulting colored fine composite particles shown as tinting strength (%).

<Equation 2>
Tinting strength (%) = 100 + {( ΔLs * value -Delta L ^* value) × 10}

Production of primary color enamel:
10g of the above sample powder, 16g of amino alkyd resin and 6g of thinner were mixed and added to a 140ml glass bottle together with 90g of 3mmφ glass beads. After mixing and dispersing for 45 minutes with a paint shaker, 50g of amino alkyd resin was added. The mixture was further dispersed for 5 minutes with a paint shaker to produce a primary color enamel.

Production of color-enamel:
The primary color enamel (12 g) and amylac white (titanium dioxide-dispersed aminoalkyd resin) (80 g) were blended and mixed and dispersed for 15 minutes with a paint shaker to produce a color-enamel.

The light resistance of each particle powder is applied to the cold-rolled steel sheet (0.8 mm x 70 mm x 150 mm) with a primary color enamel prepared to measure the coloring power described above and dried to form a coating film. Then, half of the obtained coating piece for measurement was covered with a metal foil, and “I Super UV Tester SUV-W13” (manufactured by Iwasaki Electric Co., Ltd.) was used for 6 hours continuously with an irradiation intensity of 100 mW / cm ^2. after irradiation, the hue of the UV is not irradiated portion and UV irradiation portion by covering a metal foil (L ^* value, a ^* value, b ^* value) were measured, respectively, was calculated according to the following equation 3 Indicated by ΔE ^* value.

<Equation 3>
ΔE ^* value = ((ΔL ^* value) ² + (Δa ^* value) ² + (Δb ^* value) ² ) ^1/2
ΔL ^* value: difference in L ^* value of sample to be compared with UV irradiation Δa ^* value: difference in a ^* value of sample to be compared with UV irradiation Δb ^* value: b ^* value of sample to be compared with UV irradiation difference

  The degree of detachment of the organic pigment adhering to the composite particles was evaluated in four stages by the following method. 4 indicates that the amount of the organic pigment released from the particle surface of the composite particle is small.

  2 g of the measured particle powder and 20 ml of ethanol were placed in a 50 ml Erlenmeyer flask, subjected to ultrasonic dispersion for 60 minutes, and then centrifuged at 10,000 rpm for 15 minutes to separate the measured particle powder from the solvent portion. . The obtained particles to be measured were dried at 80 ° C. for 1 hour, and the number of detached and re-aggregated organic pigments present in the field of view shown in the electron micrograph was visually observed and evaluated in four stages. .

1: 30 or more per 100 composite particles.
2: 10 or more and less than 30 per 100 composite particles.
3: 5 or more and less than 10 per 100 composite particles.
4: Less than 5 per 100 composite particles.

  The number-converted dispersion average particle diameter and volume-converted dispersion average particle diameter of the dispersion containing the colored fine composite particle powder are measured using a dynamic light scattering method “Dense System Particle Size Analyzer FPAR-1000” (manufactured by Otsuka Electronics Co., Ltd.) It was measured.

  The dispersion stability of the dispersion was evaluated by the following five steps by placing 25 ml of the dispersion in a 50 ml colorimetric tube and allowing it to stand at 60 ° C. for 1 week, then visually evaluating the degree of sedimentation of the particle powder. .

1: The non-colored part is 10 cm or more.
2: The non-colored part is 5 cm or more and less than 10 cm.
3: The non-colored part is 1 cm or more and less than 5 cm.
4: The non-colored part is less than 1 cm.
5: A non-colored part is not recognized.

The viscosity change rate of the dispersion containing colored fine composite particle powder was determined by using the “E-type viscometer EMD-R” (manufactured by Tokyo Keiki Co., Ltd.) after allowing the obtained dispersion to stand at 60 ° C. for 1 week. The viscosity value at a shear rate of D = 383 sec ⁻¹ was measured at 25 ° C., and the value obtained by dividing the amount of change in viscosity before and after standing by the value before standing was expressed as a percentage as the rate of change.

In the case of an aqueous dispersion, the coloring power of the dispersion containing colored fine composite particle powder is an aqueous solution in which the concentration of the colored fine composite particle powder is adjusted to 0.08% by weight. PGMEA solution with the powder concentration adjusted to 0.08% by weight is put in a quartz cell, and the extinction coefficient at the wavelength with the largest light absorption is set to “Self-recorded photoelectric spectrophotometer UV-2100” (manufactured by Shimadzu Corporation). The specific extinction coefficient ε _w calculated according to the following formula 4 was used. It shows that the coloring power of the dispersion containing colored micro composite particle powder is so high that the value of a specific extinction coefficient is large.

<Equation 4>
ε _w = ε _h / ε ₀
ε _w : specific extinction coefficient ε _h : extinction coefficient per unit weight of each colored fine composite particle powder ε ₀ : extinction coefficient per unit weight of the organic pigment used as a raw material of each colored fine composite particle powder

<Composite Particle 1: Production of Composite Particle Powder>
To 7.0 kg of silica 1 (average primary particle size: 16 nm, BET specific surface area value: 204.3 m ² / g, light resistance ΔE ^* : 5.36), methyl hydrogen polysiloxane (trade name: TSF484: GE Toshiba Silicone) 140 g) was added while operating the edge runner, and the mixture was stirred for 30 minutes with a linear load of 588 N / cm (60 Kg / cm). The stirring speed at this time was 22 rpm.

Next, organic pigment G (type: phthalocyanine pigment, average particle size: 100 nm, BET specific surface area value: 67.3 m ² / g, L ^* value: 29.77, a ^* value: −15.30, b ^* (Value: -1.12, C ^* value: 15.34, light resistance ΔE ^* : 8.06, ζ potential of water system: -3.6 mV, ζ potential of solvent system: -1.5 mV) 7.0 kg, It was added over 30 minutes while the edge runner was running, and further mixed and stirred for 100 minutes at a line load of 392 N / cm (40 Kg / cm) to attach the organic pigment G to the methylhydrogenpolysiloxane coating. Subsequently, it dried for 60 minutes at 80 degreeC using the dryer, and the composite particle 1 was obtained. The stirring speed at this time was 22 rpm.

The obtained composite particle 1 has an average primary particle diameter of 20 nm, a BET specific surface area value of 78.6 m ² / g, an L ^* value of 30.22, an a ^* value of −14.92, and a b ^* value of −1.10, C ^* value was 14.96, and the degree of desorption of the organic pigment was 4. The coloring power was 93%, the light resistance ΔE ^* was 2.12, the ζ potential in the aqueous system was −22.7 mV, and the ζ potential in the solvent system was −6.6 mV. The coating amount of methyl hydrogen polysiloxane was 0.53% by weight in terms of C. The adhering organic pigment G was 18.15% by weight in terms of C (corresponding to 100 parts by weight with respect to 100 parts by weight of the silica particle powder).

  From the observation result of the electron micrograph of the obtained composite particles, since almost no particles of the added organic pigment G were observed, it was confirmed that almost all of the organic pigment G was adhered to the methyl hydrogen polysiloxane coating. It was.

<Example 1-1: Production of colored fine composite particle powder>
In a 3 l beaker, 200 g of the composite particle powder obtained above and 2 l of a 0.65 mol / l sodium hydroxide aqueous solution (0.2 times the theoretical amount capable of dissolving the silica particles and the surface modifier as core particles) The pH was 13.1 and the mixture was stirred at 60 ° C. for 30 minutes. This was filtered, washed with water, and dried to obtain colored fine composite particle powder.

The obtained colored fine composite particle powder had an average primary particle diameter of 15 nm, a number-converted average particle diameter of 22 nm, a volume-converted average particle diameter of 78 nm, and a BET specific surface area value of 83.6 m ² / g. The amount of silica contained in the colored fine composite particle powder is 1.06% by weight in terms of Si. Among the hues, the L ^* value is 31.33, the a ^* value is -14.29, the b ^* value is -1.10, The C ^* value was 14.33, the coloring power was 105%, the light resistance ΔE ^* was 3.56, the ζ potential in the aqueous system was −13.8 mV, and the ζ potential in the solvent system was −6.4 mV.

<Example 2-1: Production of aqueous dispersion>
In a 140 ml glass bottle, 15 parts by weight of the colored fine composite particle powder and 100 parts by weight of water were added together with 100 g of 0.35 mmφ glass beads, and dispersed for 2 hours with a paint shaker to obtain an aqueous dispersion.

The obtained aqueous dispersion containing colored fine composite particle powder has a number-converted dispersed particle diameter of 19 nm, a volume-converted dispersed particle diameter of 42 nm, a dispersion stability of 5, a viscosity change rate of 4.8%, a ratio The extinction coefficient ε _w was 2.46.

<Example 3-1: Production of solvent-based dispersion>
In a 140 ml glass bottle, 15 parts by weight of the colored fine composite particle powder and 100 parts by weight of PGMEA were added together with 100 g of 0.35 mmφ glass beads, and mixed and dispersed for 2 hours with a paint shaker to obtain a solvent-based dispersion.

The solvent-based dispersion containing the obtained colored microcomposite particle powder has a number-converted dispersed particle size of 19 nm, a volume-converted dispersed particle size of 48 nm, a dispersion stability of 5, a viscosity change rate of 4.7%, a ratio The extinction coefficient ε _w was 2.44.

  According to the composite particle 1 and Examples 1-1 to 3-1, composite particle powder, colored fine composite particle powder, aqueous dispersion, and solvent dispersion were prepared. Various characteristics of each production condition and the obtained composite particle powder, colored fine composite particle powder, aqueous dispersion and solvent dispersion are shown.

Silica 1-4:
As core particles, silica particle powders 1 to 4 having the characteristics shown in Table 1 were prepared.

Organic pigments G, B, R, Y, Bk:
An organic pigment having the characteristics shown in Table 2 was prepared as the organic pigment.

<Manufacture of composite particle powder>
Composite particles 2-5:
Type of core particles, type and addition amount of surface modifier, line load and time for edge runner treatment in coating process of surface modifier, type of organic pigment in addition process of organic pigment, addition amount, edge runner treatment A composite particle powder was obtained in the same manner as the composite particle 1 except that the line load and time were variously changed.

  The production conditions at this time are shown in Table 3, and various characteristics of the obtained composite particle powder are shown in Table 4.

<Production of colored fine composite particle powder>
Examples 1-2 to 1-8, Comparative Examples 1-1 to 1-3:
Colored fine composite particle powder in the same manner as in Example 1-1 except that various kinds of composite particles, pH of the solution at the time of alkali dissolution, theoretical amount of alkali to be added, treatment temperature and treatment time were variously changed. Got. In addition, the density | concentration (g / 100 ml) of composite particle powder is the weight (g) of composite particle powder with respect to 100 ml of solution. In Example 1-2, freeze-drying was performed as a drying step.

  The production conditions at this time are shown in Table 5, and the various characteristics of the obtained colored microcomposite particle powder are shown in Table 6.

Comparative Example 1-4 (Japanese Patent Laid-Open No. 2005-36150, Example 1 Additional Test)
Organic pigment Y (type: quinophthalone pigment, average primary particle size: 252 nm, BET specific surface area value: 27.9 m ² / g, L ^* value: 84.21, a ^* value: 3.00, b ^* value: 91 .31, C ^* value: 91.36, light resistance ΔE ^* : 7.22, water-based ζ potential: −3.1 mV, solvent-based ζ potential: −1.4 mV) 80 g, xylene 6 g, 8 mm diameter steel 2 kg of beads were placed in a dry attritor and operated at 300 ° C. and 80 ° C. for 2 hours to obtain a quinophthalone pigment.

  Table 6 shows properties of the obtained quinophthalone pigment.

<Aqueous dispersion>
Examples 2-2 to 2-8, comparative examples 2-1 to 2-10:
An aqueous dispersion was obtained in the same manner as in Example 2-1, except that the type and blending amount of the colored fine composite particle powder were variously changed.

  Table 7 shows the production conditions at this time and various characteristics of the obtained aqueous dispersion.

Example 2-9:
An aqueous dispersion was obtained by mixing 100 parts by weight of colored fine composite particle powder and 100 parts by weight of water and kneading and dispersing them using a three-roll mill under heating conditions of 50 ° C.

  Table 7 shows the production conditions at this time and various characteristics of the obtained aqueous dispersion.

<Solvent-based dispersion>
Examples 3-2 to 3-8, Comparative examples 3-1 to 3-10:
A solvent-based dispersion was obtained in the same manner as in Example 3-1, except that the type and blending amount of the colored fine composite particle powder were variously changed.

  Table 8 shows the production conditions and the characteristics of the solvent dispersion obtained.

Example 3-9:
100 parts by weight of colored fine composite particle powder and 100 parts by weight of PGMEA were mixed and kneaded and dispersed using a three-roll mill under heating conditions of 50 ° C. to obtain a solvent-based dispersion.

  Table 8 shows the production conditions and the characteristics of the solvent dispersion obtained.

  The colored microcomposite particle powder and dispersion according to the present invention can be used as a coloring material for various applications such as commonly used paints and printing inks, regardless of whether they are aqueous or solvent-based.

Claims (6)

A colored fine composite particle powder comprising fine composite particles in which silica is encapsulated in an organic pigment. The colored fine composite particle powder according to claim 1, wherein the silica contained in the fine composite particle is 0.001 to 9% by weight in terms of Si with respect to the colored fine composite particle powder. A dispersion comprising the colored fine composite particle powder according to claim 1 or 2 dispersed in a solvent. The aqueous dispersion according to claim 3, wherein the solvent is water and / or a water-soluble organic solvent. The solvent-based dispersion according to claim 3, wherein the solvent is an organic solvent. The silica particles and the surface modifier are mixed and stirred to coat the surface of the silica particles with the surface modifier, and then the organic pigment is added, mixed and stirred, and the silica particles coated with the surface modifier are mixed. 2. The composite particle having an organic pigment attached to the particle surface is obtained, and then silica particles and a part of the surface modifier in the composite particle are dissolved using an alkaline solution. Item 3. A method for producing a colored fine composite particle powder according to Item 2.