JP2704524B2 - Heat-resistant tabular tan pigment powder and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a tan color pigment powder which is excellent in heat resistance and orientation and is non-polluting, and a method for producing the same.

The main use of the heat-resistant plate-like tan color pigment powder according to the present invention is as a coloring pigment for resins, paints, printing inks, cosmetics, and the like.

[Conventional technology]

Tan pigments are widely used as color pigments in the production of resins, paints, printing inks and cosmetics by mixing with vehicles and resins. Recently, as the demand for tan pigments has increased, there has been a strong demand for improved properties thereof, and it has been required that the pigments be excellent in heat resistance and orientation, and be non-polluting.

The reason that heat resistance is required is that, for example, when a pigment is used as a color pigment such as a resin, 300
This is because it is necessary to go through a step of heating and molding at a high temperature of about ° C. Further, the improvement of the orientation is strongly demanded from the viewpoint of the improvement of the dispersibility and the work efficiency, and in order to improve the orientation, it is necessary that the particles have a plate shape.

Conventionally, ferric hydroxide, graphite, cadmium yellow, mica titanium and the like have been widely used as tan pigments.

[Problems to be solved by the invention]

Although a heat-resistant and orientable and non-polluting tan color pigment is the most demanded at present, the above-mentioned known hydrous ferric oxide has a non-polluting but needle-like shape. The particles are dehydrated at around 200 to 250 ° C., turn into hematite and change color to red, and thus have the disadvantage of being thermally unstable. For example, as disclosed in JP-A-55-158130, JP-A-55-158132 and JP-A-59-38259, attempts have been made to improve the heat resistance of ferric hydroxide containing iron. Although various methods are used, its heat resistance is at most about 300 ° C.

The known graphite and cadmium yellow described above are lead,
Since it contains metals that are harmful to the human body such as cadmium, there is a problem in terms of pollution. Also, the above-mentioned known mica titanium,
It has the disadvantage of lacking weather resistance.

Therefore, there is a strong demand for the establishment of technical means for obtaining a tan-color pigment which is excellent in heat resistance and orientation and is pollution-free.

[Means for solving the problem]

The present inventors have conducted various studies in order to obtain a tan color pigment powder which is excellent in heat resistance and orientation and is pollution-free. As a result, the present invention has been achieved.

That is, the present invention has an average diameter of 0.5 to 5.0 μm and a thickness of 100 to 1
000 °, a plate-like ratio of 5: 1 to 500: 1, a lightness L ^* value of 40 or more, a hue θ = tan ⁻¹ b ^* / a ^* of 55 or more, Is 30 or more (where L ^* , a ^* , and b ^* are CIE 1976 (L ^* ,
a ^* , b ^* ) These values are expressed in a uniform perceived color space. ) Is a plate-like hematite particle, wherein Fe is contained inside the particle.
Fe ₂ O ₃ 20~60mol% in terms of, Zn is 0～80Mol% in terms of ZnO,
Ti is Zn or T so that 0～80Mol% of the composition in terms of TiO ₂
i or any of Zn and Ti, if necessary, further Al ₂
O ₃ conversion with Zn, to the sum of the oxides of Ti and Fe 0.1 to 200
Heat-resistant plate-like tan pigment powder composed of iron oxide particles containing Al by weight and having an average diameter of 0.5 to 5.0 μm and a thickness of 50
~ 500 °, the plate surface ratio of the plate-like hematite particles having a plate-like ratio of 10: 1 to 500: 1, the hydroxide containing Zn or the hydroxide containing Ti or both hydroxides, if necessary, further , Al
After coating with a hydroxide containing, the average diameter consisting of heating and baking in a temperature range of 70 to 1200 ° C is 0.5 to 5.0 μm, thickness
100 to 1000 °, a plate-like ratio of 5: 1 to 500: 1, a lightness L ^* value of 40 or more, a hue θ = tan ⁻¹ b ^* / a ^* of 55 or more, Is 30 or more (where L ^* , a ^* , and b ^* are CIE 1976 (L ^* ,
a ^* , b ^* ) These values are expressed in a uniform perceived color space. ) Is a plate-like hematite particle, wherein Fe is contained inside the particle.
Fe ₂ O ₃ 20~60mol% in terms of, Zn is 0～80Mol% in terms of ZnO,
Ti is Zn or T so that 0～80Mol% of the composition in terms of TiO ₂
i or Zn and Ti, if necessary, further Al
This is a method for producing a heat-resistant plate-like tan color pigment powder comprising iron oxide particles containing

4 [Action] First, the most important point in the present invention is that the average diameter is 0.5
~ 5.0μm, thickness 50 ~ 500mm, plate ratio 10: 1 ~ 500:
After coating the particle surface of the plate-like hematite particles that are 1 with a hydroxide containing Zn or a hydroxide containing Ti or both of the hydroxides, when heated and fired in a temperature range of 700 to 1200 ° C, Fe is ₂₀ to 60 mol% in terms of Fe ₂ O ₃ and Zn is Zn inside the particles.
The average diameter containing Zn or Ti or any of Zn and Ti is 0.5 to 5.0 μm, and the thickness is 100 to 80 mol% in terms of O and 0 to 80 mol% in terms of TiO _2. 1000Å
It is possible to obtain plate-like hematite particles having a plate-like ratio of 5: 1 to 500: 1, and the plate-like hematite particles are excellent in heat resistance and orientation, and have no pollution. The fact is that it is a powder.

Since the tan color pigment powder according to the present invention is iron oxide,
It has excellent weather resistance, is pollution-free, and has excellent orientation due to its plate shape.
It is excellent in heat resistance without discoloration at high temperature of ℃.

When the tan color pigment powder according to the present invention contains Al, sintering between plate-like particles can be prevented while maintaining the color of the tan color pigment powder according to the present invention.

Conventionally, as a method for producing a heat-resistant tan color pigment powder using iron oxide, there is, for example, a method described in JP-B-59-43407 and JP-B-60-8976.

In these methods, iron oxide and zinc oxide or titanium oxide are mixed, then heated and calcined, and then pulverized.
The obtained pigment particles are particles having an irregular shape or a granular shape.

Next, conditions for implementing the present invention will be described.

The plate-like hematite particles as a starting material in the present invention have an average diameter of 0.5 to 5.0 μm and a thickness of 50 to 500 °,
The plate ratio is 10: 1 to 500: 1.

Such plate-like hematite particles are obtained by subjecting an alkaline suspension having a pH of 9 or more containing hydrous ferric oxide particles or FeOx.Fe ₂ O ₃ (0 ≦ x ≦ 1) particles to a hydrothermal treatment. In the method of producing, in the alkaline suspension in advance 0.1 mol to 15.0 mol per 1 mol of Fe
1.5 to 20.0 mol% of S in terms of Si with respect to l ratio of water soluble salt and Fe
and a compound containing i, followed by hydrothermal treatment.

The coating of the plate-like hematite particles in the present invention, the compound containing Zn or the compound containing Ti or both compounds, if necessary, further plate-like hematite particles in a mixed solution of an aqueous solution comprising an Al-containing compound and an alkaline aqueous solution. After adding and mixing, it can be carried out by filtering, washing and drying.

As a compound containing Zn, zinc nitrate, zinc sulfate, zinc phosphate and the like can be used.

As a compound containing Ti, titanyl sulfate, titanium tetrachloride, titanium trichloride, or the like can be used.

As the compound containing Al, aluminum nitrate, sodium aluminate, aluminum sulfate and the like can be used.

As the alkaline aqueous solution, ammonia, urea, sodium hydroxide, and the like can be used.

The heating and firing temperature in the present invention is 700 to 1200 ° C.

If the temperature is lower than 700 ° C, hematite and Zn, Ti, Al
Is unlikely to occur.

If the temperature exceeds 1200 ° C., sintering between plate-like hematite particles occurs.

The tan pigment powder according to the present invention has an average diameter of 0.5 to 5.0.
μm, thickness 100 to 1000 °, plate ratio 5: 1 to 500: 1, lightness L ^* value is 40 or more, hue θ = tan ⁻¹ b ^* / a
^* Is 55 or more, Is 30 or more (where L ^* , a ^* , and b ^* are CIE 1976 (L ^* ,
a ^* , b ^* ) These values are expressed in a uniform perceived color space. ).

The composition of the tan color pigment powder according to the present invention is Fe ₂ O ₃ , ZnO
In the three composition diagrams of TiO ₂ and TiO ₂ , the molar composition ratio is point A (Fe
₂ O ₃ : ZnO = 60: 40), point B (Fe ₂ O ₃ : TiO ₂ = 60: 40), point C (Fe ₂ O ₃ : TiO ₂ = 20: 80), point D (Fe ₂ O ₃₎ : ZoO = 20: 80). That is, the composition of the plate-like tan pigment powder according to the present invention is such that Fe is _{20 to 6 in} terms of Fe2O3.
0 mol%, Zn is 0～80Mol% in terms of ZnO, Ti is in terms of TiO ₂ 0
It is in the range of ~ 80 mol%. When the tan pigment has Al, the content is 0.1 to 200% by weight in terms of Al ₂ O _{3 based on} the total amount of each oxide of Zn, Ti and Fe.

The tan pigment powder according to the present invention exhibits a yellow to yellow-red color.

In the present invention, the yellow system has a lightness L ^* value of 40 or more, a hue θ of 60 to 90 °, and a chroma C ^* _{ab of} 30 or more.

In the present invention, the yellow-red type has a lightness L ^* value of 40 or more, a hue θ of 55 to 60 °, and a chroma C ^* _{ab of} 30 or more.

The color of the tan color pigment powder according to the present invention can be changed depending on the size, thickness and plate ratio of the plate-like hematite particles as the starting material, and the type and amount of the coating material.

In particular, the plate-like tan color pigment powder according to the present invention has a composition in which Fe is ₃₀ to 60 mol% in terms of Fe ₂ O ₃ and Zn is 0 to 6 in terms of ZnO.
When 0 mol% and Ti are 0 to 50 mol% in terms of TiO ₂ , a brighter yellow color can be obtained, which is preferable.

〔Example〕

Next, the present invention will be described with reference to Examples and Comparative Examples.

The average diameter of the particles in the following Examples and Comparative Examples is indicated by the average value of numerical values measured from electron micrographs, and the thickness and plate ratio are the specific surface area value measured by the BET method and the average diameter. It is shown by the numerical value obtained from.

The L ^* value (brightness), a ^* value, and b ^* value were obtained by using a color machine CM-1500-A (manufactured by Color Machine Co., Ltd.) to measure L ^{* in} a Lab space of Hunter ^. Value, a
^* Value and b ^* value are measured respectively, and the International Commission on Illumination (Comm
ission Internationale de 1'Eclairage, CIE) 1976
(L ^* , a ^* , b ^* ) The values are shown according to the uniform perceived color space.

The colorimetric sample pieces consist of 0.5 g of hematite particle powder and castor oil.
1.0cc is kneaded with a Hoover-type muller to make a paste,
This paste was mixed with 4.5 g of clear lacquer, kneaded to form a paint, and the paste was applied to a cast-coated paper using a 6 mil applicator.

Example 1 Plate-like hematite particle powder (average diameter 2.5 μm, thickness 280)
Å, 99 g of titanyl sulfate dihydrate (purity: 75%) (corresponding to 121 mol% in terms of TiO ₂ with respect to plate-like hematite particles) is added to an aqueous suspension 5 containing 50 g of a plate-like ratio of 89: 1). After mixing and stirring, heat and hold at 95 ° C. for 90 minutes.

Further, by adjusting the pH to 6.5 by adding NaOH, a hydrate layer of TiO ₂ was formed on the surface of the plate-like hematite particles.

The suspension containing the plate-like hematite particles whose particle surface is coated with a hydrate layer of TiO ₂ is filtered by a conventional method, washed with water,
After drying, it was heated and baked at 800 ° C. for 1.0 hour.

Obtained particle powder after heating and sintering, as a result of electron microscopic observation, is a plate-like particle having an average diameter of 2.6 μm, a thickness of 480 mm, and a plate-like ratio of 54: 1. Was 45 mol% in terms of Fe ₂ O ₃ and Ti was 55 mol% in terms of TiO ₂ .

The color has a lightness L ^* value of 50.1 and a hue θ = tan ⁻¹ b ^*.
/ a ^* is 58.2, Was 38.8, a yellow-red tan pigment powder.

Further, 10 g of the above yellow-red tan pigment powder was heated and baked at 500 ° C. for 24 hours. The color of the fired product is lightness L ^* value of 50.2,
Hue θ = tan ^-1 b ^* / a ^* is 58.3, Was 38.9, and there was almost no discoloration as compared to before heating and firing.

Example 2 Plate-like hematite particle powder (average diameter 2.0 μm, thickness 440)
Å, 90.2 g of zinc sulfate heptahydrate in a water suspension 5 containing 50 g (plate ratio 46: 1) (100 m in terms of ZnO based on plate-like hematite particles)
ol%. ), Mix and stir, then heat,
Hold at 50 ° C. for 90 minutes.

Furthermore, Zn (OH) ₂ was generated on the surface of the plate-like hematite particles by adjusting the pH to 9.0 by adding NH ₄ OH.

The suspension containing the plate-like hematite particles whose particle surfaces are coated with a layer of Zn (OH) ₂ is filtered, washed and washed with a conventional method.
After drying, it was heated and fired at 850 ° C. for 2.0 hours.

Obtained particle powder after heating and sintering, as a result of observation by an electron microscope, is a plate-shaped particle having an average diameter of 2.5 μm, a thickness of 680 mm, and a plate-like ratio of 37: 1. Was 54 mol% in terms of Fe ₂ O ₃ and Zn was 46 mol% in terms of ZnO.

The color has a lightness L ^* value of 46.2 and a hue θ = tan ⁻¹ b ^*.
/ a ^* is 66.3, Was 31.1 yellow tan pigment powder.

Further, 10 g of the above yellow tan pigment powder was heated and baked at 500 ° C. for 24 hours. The color of the heat-baked product was a lightness L ^* value of 46.1, a hue θ = tan ⁻¹ b ^* / a ^* of 66.2, Was 31.0, and there was almost no discoloration as compared to before heating and firing.

Example 3 Plate-like hematite particle powder (average diameter 2.8 μm, thickness 250
Å, 116 g of zinc sulfate heptahydrate (129 mol in terms of ZnO based on plate-like hematite particles) in an aqueous suspension 5 containing 50 g of a plate-like ratio of 112: 1.
l%. ) And titanyl sulfate dihydrate (purity 75%) 7
6.3 g (corresponding to 57 mol% in terms of TiO ₂ with respect to plate-like hematite particles) and 360 g of urea are added, mixed and stirred, heated, and maintained at 95 ° C. for 180 minutes.

A suspension containing plate-like hematite particles whose particle surfaces are coated with Zn (OH) ₂ and TiO ₂ hydrates was washed, dried and dried by a conventional method, and then heated and fired at 1000 ° C. for 30 minutes. .

The obtained particle powder after heating and sintering, as a result of electron microscopic observation, is a plate-shaped particle having an average diameter of 3.0 μm, a thickness of 700 mm, and a plate ratio of 43: 1. 4 but 38 mol% calculated as Fe ₂ O _3, Ti is 21 mol% in terms of TiO _2, Zn is in terms of ZnO
It was 1 mol%.

The color has a lightness L ^* value of 57.2 and a hue θ = tan ⁻¹ b ^*.
/ a ^* is 73.9, Was 44.8.

Further, 10 g of the above yellow tan pigment powder was heated and baked at 500 ° C. for 24 hours. The color of the fired product was a lightness L ^* value of 57.2, a hue θ = tan ⁻¹ b ^* / a ^* of 73.8, Was 44.9, and the color was hardly changed as compared with that before the heating and firing.

Example 4 Plate-like hematite particle powder (average diameter 2.5 μm, thickness 260
Å 0.313 mol of titanium tetrachloride (10% in terms of TiO _{2 with} respect to plate-like hematite particles) in an aqueous suspension 5 containing 50 g of plate-like ratio 96: 1)
This corresponds to 0 mol%. ), 126 g of anhydrous aluminum sulfate and 282 g of urea were added, mixed, stirred, and heated.
Hold for a minute.

After the particle surface was over, water washing, drying by a conventional method a suspension containing plate-like hematite particles coated with _{TiO 2 · nH 2 O, Al} 2 O 3 · nH 2 O, 1.0 hours at 850 ° C. It was fired.

As a result of observation with an electron microscope, the obtained particle powder after heating and firing was a plate-like particle having an average diameter of 2.7 μm, a thickness of 570 mm, and a plate-like ratio of 47: 1. X-ray fluorescence analysis showed that Fe was Fe ₂ O ₃
The conversion was 51 mol%, the Ti was 49 mol% in terms of TiO ₂ , and the Al amount was 45 wt% in terms of Al ₂ O ₃ with respect to the total amount.

The color has a lightness L ^* value of 54.4 and a hue θ = tan ⁻¹ b ^*.
/ a ^* is 70.2, Was 46.8.

Further, 10 g of the above yellow tan pigment powder was heated and baked at 500 ° C. for 24 hours. The color of the heat-baked product was a lightness L ^* value of 54.5, a hue θ = tan ⁻¹ b ^* / a ^* of 70.1, Was 46.9, and the color was hardly discolored as compared to before heating and firing.

Example 5 Plate-like hematite particle powder (average diameter 2.8 μm, thickness 250
Å, 102 g of zinc sulfate heptahydrate (113 mol in terms of ZnO based on plate-like hematite particles) in an aqueous suspension 5 containing 50 g of a plate-like ratio of 112: 1.
l%. ) And titanyl sulfate dihydrate (75% pure) 3
0.7g (37.5mol% in terms of TiO _{2 based on} plate-like hematite particles)
Corresponds to. ), Aluminum nitrate 9 hydrate and urea 22
Add 8 g, mix and stir, heat and hold at 95 ° C. for 180 minutes.

The suspension containing the plate-like hematite particles whose particle surfaces are coated with hydrates or hydroxides of Zn, Ti, and Al is filtered, washed with water, dried, and then fired at 950 ° C. for 1.0 hour. did.

The obtained particle powder after heating and sintering was a particle exhibiting a plate shape with an average diameter of 2.9 μm, a thickness of 520 °, and a plate ratio of 56: 1 as a result of electron microscopic observation. 4 but 41 mol% calculated as Fe ₂ O _3, Ti is 15 mol% in terms of TiO _2, Zn is in terms of ZnO
A 4 mol%, Al content is 19 wt% in terms of Al ₂ O _3, relative to the total amount
Met.

The color has a lightness L ^* value of 58.1 and a hue θ = tan ⁻¹ b ^*.
/ a ^* is 73.2, Was 45.0.

Further, 10 g of the above yellow tan pigment powder was heated and baked at 500 ° C. for 24 hours. The color of the heat-baked product was a lightness L ^* value of 58.0, a hue θ = tan ⁻¹ b ^* / a ^* of 73.1, Was 44.9, and the color was hardly changed as compared with that before the heating and firing.

〔The invention's effect〕

The tan color pigment powder according to the present invention is excellent in heat resistance and orientation, as shown in the above Examples, and is non-polluting. It is suitable as a coloring pigment for use.

[Brief description of the drawings]

FIG. 1 shows a three-composition diagram of Fe ₂ O ₃ , ZnO and TiO _2. The range connecting points A to D corresponds to the molar composition of the tan color pigment powder according to the present invention. Range.

Claims (4)

(57) [Claims] An average diameter of 0.5 to 5.0 μm and a thickness of 100 to 1000 mm.
A plate-like ratio of 5: 1 to 500: 1, a lightness L ^* value of 40 or more, a hue θ = tan ⁻¹ b ^* / a ^* of 55 or more, Is 30 or more (where L ^* , a ^* , and b ^* are CIE 1976
(L ^* , a ^* , b ^* ) are values displayed in the uniform perceived color space. ), Wherein Fe is ₂₀ to 60 mol% in terms of Fe ₂ O ₃ and Zn is 0 to 8 in terms of ZnO in the particle.
A heat-resistant plate-like tan color pigment powder comprising iron oxide particles containing Zn or Ti or any of Zn and Ti such that the composition is 0 mol% and Ti is 0 to 80 mol% in terms of TiO ₂ . 2. The plate-like hematite particles having an average diameter of 0.5 to 5.0 μm, a thickness of 50 to 500 ° and a plate ratio of 10: 1 to 500: 1 are coated with Zn-containing hydroxide or Ti. After coating with the containing hydroxide or the both hydroxides, the average diameter is characterized by being heated and fired in a temperature range of 700 to 1200 ° C is 0.5 to
5.0 μm, thickness 100-1000 mm, plate ratio 5: 1-500: 1
And the lightness L ^* value is 40 or more, and the hue θ = tan ⁻¹ b ^*
/ a ^* is 55 or more, Is 30 or more (where L ^* , a ^* , and b ^* are CIE 1976
(L ^* , a ^* , b ^* ) are values displayed in the uniform perceived color space. ), Wherein Fe is ₂₀ to 60 mol% in terms of Fe ₂ O ₃ and Zn is 0 to 8 in terms of ZnO in the particle.
Production of heat-resistant plate-like tan pigment powder comprising iron oxide particles containing Zn or Ti or any of Zn and Ti so that the composition becomes 0 mol% and Ti becomes 0 to 80 mol% in terms of TiO ₂ Law. 3. The heat resistant iron oxide particles according to claim 1, wherein the particles contain 0.1 to 200% by weight of Al, based on the total of oxides of Zn, Ti and Fe, in terms of Al ₂ O _3. Plate-like tan pigment powder. 4. The process for producing a heat-resistant tabular tan pigment powder comprising iron oxide particles according to claim 2, wherein the surface of the plate-like hematite particles is coated with a hydroxide containing Al.