Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G51/00—Compounds of cobalt
  • C01G51/04—Oxides; Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/0009—Pigments for ceramics
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/62—Metallic pigments or fillers

Definitions

• the present invention relates to a method for producing a granular cobalt oxide black pigment and a granular cobalt oxide black pigment. Specifically, the proportion of cobalt (divalent) in the total cobalt contained is 35 to 70%.
• Black pigments used in black matrix coloring compositions and the like are required to be excellent in properties such as blackness, hue, coloring power, concealment, and the like, and inexpensive, such as carbon black and Various metal oxide pigments are used depending on applications.
• metal oxide pigments which are alternative materials, are attracting attention.
• Representative examples of metal oxide pigments include metal oxide particles having a single composition such as manganese oxide and copper oxide, and composite oxide particles of these metal elements. Is excellent in blackness.
• Patent Document 1 a wet reaction method, as represented by Patent Document 1, for producing tricobalt tetroxide using an oxidizing gas after neutralizing a cobalt salt aqueous solution.
• Patent Document 2 a dry method for producing tricobalt tetroxide by firing cobalt hydroxide as represented by Patent Document 2.
• the applicant of the present invention is characterized in that it is an acid oxide containing at least cobalt, and the ratio power of divalent cobalt in all cobalt is 0% to 70%.
• a cobalt black-containing granular black pigment was proposed (see Patent Document 3). This cobalt-containing granular black The pigment is neutralized with cobalt (divalent) salt using an alkali metal salt containing alkali metal salt at a liquid temperature of 40 ° C or lower to produce a slurry containing cobalt hydroxide (divalent).
• inert gas is continuously published in the slurry, and the obtained cobalt hydroxide (divalent) is filtered, washed, dried and crushed, and then at 400 ° C to 800 ° C. Manufactured by firing.
• Patent Document 1 Japanese Patent Application Laid-Open No. 2002-68750
• Patent Document 2 Japanese Patent Laid-Open No. 2003-138160
• Patent Document 3 International Publication No. 2006Z030896 Pamphlet
• a black pigment suitable for a black matrix coloring composition is required to have not only blackness but also stable high electrical resistance.
• the particles constituting the powder have excellent blackness, that the particles are finely divided in a uniform manner, and that there is little aggregation.
• the manufacturing method must also be a highly productive means.
• Patent Document 1 discloses a method for producing tetracobalt tetraacid tetracobalt, which can be produced only by a wet reaction.
• the particle size obtained by only a wet reaction remains fine and no heat treatment (firing etc.) is performed. Due to these reasons, the tricobalt tetraacid obtained by the production method of the literature has a fine particle size, so the blackness is hardly a sufficient level. Further, it lacks stability in form and is unsuitable for use as a black matrix coloring composition that undergoes heat treatment.
• Patent Document 2 discloses a cobalt tetroxide-cobalt powder.
• 150 to 800 ° C is obtained by heating hydroxy cobalt carbonate or cobalt hydroxide in an oxidizing atmosphere. It is characterized by firing at a temperature of.
• a cobalt tetroxide-cobalt powder can be obtained simply by calcining a conolate compound.
• blackness is sufficiently black due to the high ratio of the value cobalt.
• the object of the present invention is to provide excellent blackness and high electrical resistance, which should be provided as a black pigment powder for forming a black electrode such as a plasma display or a plasma addressed liquid crystal or a light shielding layer.
• the inventors of the present invention have found that the wet neutralization calcining method has superior blackness and other characteristics as compared with the conventional tricobalt tetraoxide, and has a high divalent cobalt content.
• the present inventors have found that a cobalt black pigment can be produced and completed the present invention.
• the present invention neutralizes a cobalt (divalent) salt aqueous solution and an alkali solution at pH 10 to 13 and starts mixing neutralization or after mixing neutralization. Is maintained at 10 ° C. to 40 ° C. to continuously publish an oxygen-containing gas in the mixed solution to produce a cobalt hydroxide precursor, and the produced precursor is filtered, washed, dried, After pulverization, the precursor is calcined in a sealed atmosphere at 500 ° C to 850 ° C for 0.5 to 3 hours. Is called the first manufacturing method
• the present invention provides a mixed neutralization of a cobalt (divalent) salt aqueous solution and an alkaline solution at a pH of 10 to 13, and the temperature of the mixed solution after the start of the mixed neutralization or after the completion of the mixed neutralization.
• This is a method for producing a cobalt oxide black pigment (hereinafter referred to as a second production method).
• the granular cobalt oxide black pigment of the present invention is black particles whose main component is at least a cobalt oxide, and depending on required properties, Si, Al, Mn, Ni, Zn, Cu, Mg, At least one component such as Ti, Zr, W, Mo, and P may be selected and contained.
• a cobalt (divalent) salt aqueous solution and an alkali solution are mixed and neutralized at a pH of 10 to 13, and after mixing neutralization starts or after mixing neutralization ends, Oxygen contained in the mixture while maintaining the temperature of the mixture at 10 ° C to 40 ° C Gas is continuously published to produce a cobalt hydroxide precursor, and the produced precursor is filtered, washed, dried and crushed, and then in a sealed atmosphere at 500 ° C to 850 ° C. The precursor is calcined for 0.5 to 3 hours.
• the neutralization pH is lower than 10
• trivalent cobalt hydroxide is easily generated during neutralization. Not only does this interfere with the formation of a cobalt hydroxide precursor, but also a cobalt hydroxide precursor. The particle size becomes fine, resulting in problems such as poor filterability and the possibility of sintering between particles when firing, which will be described later.
• the pH is higher than 13
• cobalt (divalent) salts are susceptible to excessive oxidation and may produce trivalent cobalt hydroxide.
• the pH during neutralization is preferably 11-12.
• the mixed solution is heated to a temperature of 10 after the start of neutralization of the cobalt (divalent) salt aqueous solution and the alkali solution or after the end of the neutralization. It is also important to continuously publish the oxygen-containing gas while maintaining the temperature between 40 ° C and 40 ° C.
• air oxygen concentration: 22 vol%
• the oxygen concentration is 5 vol% or more and less than 22 vol%.
• active gas enriched air it is preferred to use active gas enriched air.
• the inert gas used is preferably nitrogen for practical use. By reducing oxygen in the air in this range, it becomes easy to produce the target cobalt hydroxide precursor without precise control of the publishing gas amount and bubbling time.
• air is used as the publishing oxygen-containing gas, it is possible to publish from 0.01 N liter Z (L 'min) to 0.3 N liter Z (L * min) for 1 hour to 3 hours per unit volume of the mixture. preferable.
• the publishing gas speed and publishing time may be adjusted according to the total amount of oxygen in the publishing gas.
• the cobalt (divalent) salt used as a starting material is a salt that is soluble in water, such as cobalt sulfate (divalent), salt-cobalt (divalent), or nitrate (bivalent) nitrate. It is preferable. Further, as alkali used for neutralization, hydroxy-alkali hydroxide such as sodium hydroxide and potassium hydroxide is industrially used. The oxygen-containing gas used in the reaction is preferably air for practical use.
• the amount of liquid mixture at the beginning of mixing is small by simply mixing an aqueous solution whose main component is a cobalt (divalent) salt and an alkali solution.
• an alkaline solution prepared in the pH range of 10 to 13 in an amount sufficient for stirring.
• a liquid may be prepared, and a cobalt (divalent) salt aqueous solution may be added to the alkaline solution to produce a hydroxy-cobalt precursor. Even in such a case, it is important to maintain the pH of the hydroxide-cobalt precursor slurry at 10-13 while adding more alkaline solution.
• Filtration and washing are performed to remove by-products, unreacted substances, and excess alkali components.
• by-products, unreacted substances, and excess alkali remain, the blackness and electrical resistance of the granular cobalt oxide black pigment to be finally produced may be affected.
• the moisture content of the dried product obtained by evaporating moisture is preferably 1% by mass or less.
• the moisture content is controlled by appropriately adjusting the drying temperature and drying time. By making the amount of water contained 1% by mass or less, if it is more, the amount of water vapor generated in the firing step described later can be reduced, and a reduction in firing efficiency can be prevented. More preferably, the water content is adjusted to 0.1% by mass to 0.6% by mass.
• a crushing operation is performed on a dried body having a water content of 1% by mass or less. If the crushing operation is not performed, the dried body is aggregated and supplied to a firing step to be described later, resulting in problems such as further aggregation being promoted by the firing.
• a high-speed rotating hammer mill, impact mill, disk mill or the like is preferable.
• the dried body thus obtained is calcined in a sealed atmosphere at 500 ° C to 850 ° C for 0.5 to 3 hours.
• firing may be performed in the atmosphere, but there is no need to introduce air in an enclosed container. The reason for this is to suppress peroxidation caused by introducing excessive air.
• the air volume in the firing device may be adjusted to about 0.01 to 0.5 m 3 / kg with respect to the dry mass. This air capacity is determined by the internal volume of the baking apparatus.
• the firing time and the firing temperature are important for promoting the dehydration of cobalt hydroxide and improving the crystallinity of the divalent oxide while suppressing the sintering of the produced granular cobalt oxide black pigment. is there.
• the firing temperature is less than 500 ° C, sufficient blackness and high electrical resistance that the shape change is not sufficient cannot be obtained.
• the temperature exceeds 850 ° C the sintering of the particles proceeds and the post-process However, there is a risk that aggregation and solidification cannot be released.
• a more preferable temperature range of this firing temperature is 600. C-800. C.
• the firing time is less than 0.5 hours, even if a high temperature range is selected within the above temperature range, the shape change is sufficiently strong or uneven, resulting in sufficient blackness. High electrical resistance may not be obtained. If it exceeds 3 hours, sintering proceeds even if a low temperature range is selected within the above temperature range, and not only coagulation / solidification cannot be canceled in the subsequent process, but also the oxidation of cobalt occurs in the firing process.
• the divalent cobalt content may be low.
• the fired product obtained in this way exhibits a slight aggregation and solidification state, and thus the intended granular black pigment can be obtained by carrying out a conventional crushing treatment.
• the granular acid-cobalt black pigment obtained as described above can be further increased in electrical resistance by being processed by a wheel-type kneader having an action of compression 'shear'. It is.
• a preferable treatment condition is a treatment for 10 to 90 minutes at a linear pressure of 30 kgfZcm to 160 kgfZcm. This increases the electrical resistance of the granular cobalt oxide black pigment by about one power. Further preferable conditions are 30 kgfZcm to 120 kgfZcm.
• a cobalt (divalent) salt aqueous solution and an alkali solution are mixed and neutralized at a pH of 10 to 13, and after mixing neutralization starts or after mixing neutralization ends, While maintaining the temperature of the mixture at 10 ° C to 40 ° C, oxygen-containing gas is continuously published in the mixture to produce a cobalt hydroxide precursor, and the produced precursor is filtered and washed. After drying, crushing, firing the precursor at 500 ° C. to 850 ° C. in an inert gas-enriched air atmosphere maintained at an oxygen concentration of 15% by volume or more and less than 22% by volume. It is a feature.
• the slurry containing the cobalt hydroxide precursor obtained by the wet reaction is filtered, washed, the contained water is evaporated, and further pulverized.
• the precursor is calcined at 500 ° C to 850 ° C in an inert gas-enriched air atmosphere maintained at an oxygen concentration of 15% by volume or more and less than 22% by volume. Important to do It is.
• the granular oxidized cobalt black pigment to be produced is not limited by the firing time.
• the degree of acid can be adjusted.
• the oxygen concentration in the firing atmosphere exceeds 22% by volume, it is in an air- or oxygen-rich state, so it is necessary to take great care in adjusting the firing time. volume. If the ratio is less than 0, the firing time for producing the target granular acid / cobalt black pigment has to be long, and the sintering proceeds and aggregation / solidification may not be released later.
• the firing temperature is 500 ° C to 850 ° C.
• the reason for setting the range is the same as in the first manufacturing method.
• a preferred temperature range is 600 ° C to 800 ° C.
• the firing time tends to be lower in the oxygen concentration in the firing atmosphere, so a slightly longer firing time can be taken.
• the granular cobalt oxide black pigment of the present invention preferably has a proportion of divalent cobalt in the total cobalt content of 35% to 70%.
• the ratio of divalent cobalt in the total cobalt content is the value obtained by dividing the divalent cobalt content contained in the entire particle by the total cobalt content contained in the entire particle, multiplied by 100. This value is Common forms of acid cobalt include tetraacid tetracobalt (Co O), acid
• Cobalt (CoO and Co 2 O) is available. Co O is occupied by divalent cobalt in the total cobalt
• CoO is all divalent cobalt and Co O
• All of the 2 3 cores are trivalent cobalt.
• the granular cobalt oxide black pigment of the present invention differs from that of cobalt oxide in the proportion of divalent cobalt in the total cobalt, and the black effect that is the effect of the present invention depends on the element composition. Compatibility and high electrical resistance were achieved.
• Blackness is insufficient when the proportion of divalent cobalt in the total cobalt is less than 35% It becomes. If it exceeds 70%, the pigment exhibits a blue-green color instead of a black pigment, and the effect of the present invention cannot be exhibited.
• the proportion of divalent cobalt in the total conoleto is more preferably 40 to 60%.
• the granular cobalt oxide black pigment of the present invention preferably has a granular particle shape.
• Plate-like particles are not only inferior in dispersibility and fluidity, but in the case of plate-like particles, the particle size in the thickness direction is about several tens of nm, and the light absorption wavelength is biased.
• the hue as a black pigment is deteriorated, which is insufficient for forming a black electrode such as a plasma display or a plasma addressed liquid crystal in which blackness is regarded as important, and a light shielding layer.
• the term “granular” as used herein means a spherical shape or a spindle shape, and excludes plate-like particles.
• the granular cobalt oxide black pigment of the present invention has a total cobalt content of 60% by mass to 80% by mass with respect to the entire particle, and a divalent cobalt content with respect to the entire particle of 24% by mass to 50%. It is preferable that it is mass%. More preferably, the total cobalt content with respect to the whole particle is 65% by mass to 75% by mass, and the divalent cobalt content with respect to the whole particle is 26% by mass to 45% by mass.
• the blackness is sufficient, and when it is 50% by mass or less, the blackness is similarly sufficient.
• the granular cobalt oxide black pigment of the present invention preferably has a primary particle diameter of 0.02 ⁇ m to 0.6 ⁇ m.
• the primary particle diameter is 0.02 m or more, the tint is prevented from being reddish, and the dispersibility is improved.
• the thickness is 0.6 m or less, the color becomes sufficient and the coloring power is also sufficient. It is more preferable that the primary particle diameter is 0.05 / ⁇ ⁇ to 0.3 ⁇ because the hue and coloring power are easily balanced.
• the granular cobalt oxide black pigment of the present invention preferably has an L value of 38 or less and a b value of 0 or less at the time of evaluation of colorability. More preferably, the L value is 36 or less, and the b value is 0.5 or less.
• the evaluation method of colorability is as follows. Add 0.5g of black pigment and titanium oxide (R800 manufactured by Ishihara Sangyo Co., Ltd.) l. Add 3cc of castor oil to 5g and knead with Hoover-type Mahler. this Sample kneaded 2.
• the granular cobalt oxide black pigment of the present invention is characterized by high electrical resistance.
• the electrical resistance value is preferably 1 ⁇ 10 5 ⁇ cm or more. More preferably, it is 5 ⁇ 10 5 Q cm or more, and still more preferably IX 10 6 ⁇ cm.
• the electrical resistance is lower than 1 X 10 5 Q cm, it is difficult to sufficiently enhance the function as a material for forming a black matrix array type high light-shielding film such as a plasma display or plasma addressed liquid crystal. Absent.
• the obtained cobalt hydroxide precursor slurry was filtered and washed, and the obtained cake was dried at 80 ° C.
• the dried product thus obtained had a water content of 0.5% by mass.
• the water content was measured according to the JIS K 5101-1991 heating loss measurement method. Further, this dried product was crushed with a hammer mill.
• the crushed dry product thus obtained was calcined at 700 ° C for 2 hours in a sealed atmosphere to obtain a particle powder.
• the obtained particle powder was evaluated by the following method. Table 1 shows the evaluation results.
• the sample was completely dissolved in acid, and the content of conoleto was determined by ICP.
• the trivalent iron ion concentration was determined by calculating the difference between the divalent iron ion concentration added by force and the divalent iron ion concentration obtained by titration.
• the particle shape was observed with a scanning microscope (magnification 40,000 times). At the same time, the diameter of 200 particles was arbitrarily measured, and the number average value was taken as the primary particle diameter.
• the samples were placed 10g in the holder, after forming the pressure 600KgfZcm 2 in tablet mosquitoes ⁇ Ete 25Paiiotapaiiota phi, was measured in a pressurized state of attaching the electrode 150kgfZcm 2.
• the electrical resistance value was calculated from the thickness, cross-sectional area and resistance value of the sample used for the measurement.
• a granular powder was obtained in the same manner as in Example 1 except that the oxygen concentration was 10% by volume and neutralized 10 liters Z minutes during neutralization, and after mixing was blown into the reaction slurry at 30 liters Z minutes. .
• the obtained particle powder was evaluated in the same manner as in Example 1.
• a particle powder was obtained in the same manner as in Example 1 except that firing was performed in an atmosphere maintained at an oxygen concentration of 18% by volume.
• the obtained particle powder was evaluated in the same manner as in Example 1.
• a particle powder was obtained in the same manner as in Example 1 except that the reaction slurry temperature was 50 ° C. The obtained particle powder was evaluated in the same manner as in Example 1.
• a particle powder was obtained in the same manner as in Example 1 except that the pH of the reaction slurry was 9. The obtained particle powder was evaluated in the same manner as in Example 1.
• a particle powder was obtained in the same manner as in Example 1 except that outside air was introduced into the baking apparatus and the gas concentration was about the same as that of the outside air.
• the obtained particle powder was evaluated in the same manner as in Example 1.
• Particle powder was obtained in the same manner as in Example 1 except that nitrogen was introduced into the firing apparatus and the firing atmosphere was maintained at 10% by volume of oxygen.
• the obtained particle powder was obtained in the same manner as in Example 1.
• the particle powders of the examples have excellent blackness, high electrical resistance, small particle size, sharp particle size distribution, black matrix coloring composition, and plasma display. It is excellent as a material for forming black electrodes such as plasma addressed liquid crystal and light shielding layers.
• the particle powders of Comparative Examples 1 and 2 contain divalent cobalt in the total cobalt or the entire particle because the reaction conditions deviate from the manufacturing conditions of the production method of the present invention. This is a problem in terms of various properties, such as a decrease in the amount, inferior blackness and hue.
• the particle powder of Comparative Example 3 was treated by introducing outside air during firing, so that the proportion of divalent cornole in the total cobalt decreased, and this was caused by The hue was inferior.
• the particle powder of Comparative Example 4 was treated in a low oxygen concentration atmosphere at the time of firing, but due to the remaining of the acid oxycobalt particles that were insufficiently fired and sufficiently converted to acid-hycobalt, the primary particle diameter force and ratio were reduced.
• the surface area was also large. As a result, various characteristics such as blackness, hue, and coloring power were remarkably inferior.
• the granular cobalt oxide black pigment produced by the production method of the present invention has excellent blackness and high electrical resistance in which the proportion of divalent cobalt in the total cobalt is high. And has a small particle size and a sharp particle size distribution, it is suitable for applications such as black electrodes for plasma displays and plasma addressed liquid crystals, and black pigment powder for forming a light shielding layer.

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• Inorganic Compounds Of Heavy Metals (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)

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• 2007
  • 2007-03-22 WO PCT/JP2007/055863 patent/WO2007122954A1/ja active Application Filing
  • 2007-03-22 KR KR1020087014880A patent/KR101313045B1/ko not_active IP Right Cessation
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