JP2013209264A - Heat-resistant black powder, method for manufacturing the same, and coating material and resin composition using the heat-resistant black powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-resistant black powder suitable as a coloring material of a coating material or a resin composition because of being excellent in heat resistance and exhibiting little change of hue (blackness degree).SOLUTION: A heat-resistant black powder includes a composite oxide containing Fe, Mn, Mg and/or Ca, has a change in hue in heat resistance test at 800°C of at most 0.5, and a magnetization value of at most 2.0 Am/kg, is constituted of a hematite phase and a bixbite phase, and can be obtained by mixing an iron compound, a manganese compound and a magnesium compound or a calcium compound, and firing the obtained mixture in the temperature range of 830 to 1,000°C.

Description

  The present invention relates to a black powder having excellent heat resistance and little change in blackness even at high temperatures.

Currently, black pigments are used as various coloring materials. As black pigments, carbon black, magnetite (Fe ₃ O ₄ ) and the like are known. These pigments cannot be said to be excellent in heat resistance.
Further, as a black pigment having heat resistance, Cr-based composite oxides and the like are also known. However, problems such as high environmental load in terms of containing Cr are regarded as problems.

  Therefore, there is a demand for black pigments composed of harmless elements and having high heat resistance.

  At present, various improvements have been made on black pigments having heat resistance (Patent Documents 1 to 3).

Japanese Patent Laid-Open No. 10-279314 Japanese Patent Publication No. 47-30085 Japanese Patent Laid-Open No. 5-221653

  A black pigment having excellent heat resistance and little change in blackness even at high temperatures has not yet been obtained.

  That is, Patent Documents 1 to 3 describe that a composite oxide containing Fe and Mn is used as a black pigment, but it is difficult to say that heat resistance is excellent at high temperatures.

  An object of the present invention is to provide a black powder having excellent heat resistance and little change in hue (blackness) even at high temperatures.

  The object can be achieved by the present invention as follows.

That is, the present invention is a heat-resistant black powder made of a composite oxide containing Fe, Mn, Mg and / or Ca, and the change in hue in a heat test at 800 ° C. is 0.5 or less. In the X-ray diffraction spectrum of the heat-resistant black powder, the magnetization value is 2.0 Am ² / kg or less, and the intensity ratio 100 of the (104) plane of the hematite phase is 100% of the (222) plane of the bixbite phase. It is a heat-resistant black powder characterized by an intensity ratio of 45 to 250 (Invention 1).

  Further, the present invention is the heat-resistant black powder according to the present invention 1, wherein the Mg content is 0.01 to 5.0% by weight, or the Ca content is 0.01 to 5.0% by weight. This is a heat-resistant black powder (Invention 2).

  Moreover, this invention is the heat resistant black powder of this invention 1 or 2, Comprising: Fe / Mn (molar ratio) is 1.0-10.0 heat resistant black powder (this invention 3). ).

Moreover, this invention is the heat resistant black powder in any one of this invention 1-3, Comprising: It is a heat resistant black powder whose blackness (L ^* value) is 25.0 or less (this invention 4).

In the present invention, an iron compound, a manganese compound, a magnesium compound and / or a calcium compound are mixed at a Fe / Mn ratio (molar ratio) of 1.0 to 10.0 and the magnesium compound is MgCO ₃ (MgCO _3. the amount / (iron compound + manganese compound + magnesium compound)) is 0.01~10.0wt%, or the mixing ratio of the calcium compound as CaCO ₃ (CaCO ₃ weight / (iron compound + manganese compound + calcium compound)) is The method for producing a heat-resistant black powder according to any one of claims 1 to 4, wherein the mixture is mixed so as to be 0.01 to 10.0 wt%, and the obtained mixture is fired at a temperature range of 830 to 1000 ° C. Invention 5).

  Moreover, this invention is the coating material which mix | blended the heat-resistant black powder in any one of this invention 1 thru | or 4 in the coating-material base material (this invention 6).

  Moreover, this invention is a resin composition colored using the heat-resistant black powder in any one of this invention 1 thru | or 4 (this invention 7).

  The heat-resistant black powder according to the present invention is suitable as a colorant for paints or resin compositions because it has excellent heat resistance and little change in blackness even at high temperatures.

It is an X-ray-diffraction pattern (diffraction angle is 20-40 degrees) of the heat resistant black powder obtained in Example 1 of this invention.

  The configuration of the present invention will be described in more detail as follows.

  First, the heat-resistant black powder according to the present invention will be described.

  The heat-resistant black powder according to the present invention is composed of a composite oxide containing Fe, Mn, Mg and / or Ca.

The Mg and / or Ca content of the heat-resistant black powder according to the present invention is preferably 0.01 to 5.0% by weight. When the content of Mg and / or Ca is less than 0.01% by weight, the heat resistance of the black powder is lowered and the blackness is changed at high temperature. When the content of Mg or Ca exceeds 5.0% by weight, the blackness is low (L ^* value is high) and it is difficult to say that it is a black pigment. The content of Mg or Ca is more preferably 0.01 to 4.0% by weight, still more preferably 0.05 to 3.0% by weight.

It is preferable that Fe / Mn (molar ratio) of the heat-resistant black powder according to the present invention is 1.0 to 10.0. When Fe / Mn (molar ratio) is less than 1.0, the b ^* value is high, and it is difficult to say that it is a black powder. The heat resistance of the black powder is reduced, and the blackness may change at high temperatures. . When Fe / Mn (molar ratio) exceeds 10.0, the hematite phase increases and the a ^* value becomes high, which is difficult to say as a black pigment. More preferable Fe / Mn (molar ratio) is 1.2 to 9.0, and still more preferably 1.5 to 8.5.

  The heat-resistant black powder according to the present invention has a color change of 0.5 or less in a heat resistance test at 800 ° C. When the hue change exceeds 0.5, the heat resistance is low, which is not preferable. More preferably, the change in hue is 0.4 or less, and even more preferably 0.01 to 0.35.

The magnetization value of the heat-resistant black powder according to the present invention is 2.0 Am ² / kg or less. When the magnetization value exceeds 2.0 Am ² / kg, a large amount of spinel phase is present, which is not preferable because heat resistance is lowered. A more preferable magnetization value is 1.8 Am ² / kg or less, and still more preferably 0.01 to 1.5 Am ² / kg.

In the X-ray diffraction spectrum of the heat-resistant black powder according to the present invention, the intensity ratio of the (222) plane of the bixbite phase is 45 to 250 with respect to the intensity ratio 100 of the (104) plane of the hematite phase. When the intensity ratio is less than 45, the ratio of the hematite phase is high and the a ^* value (redness) becomes strong. When the intensity ratio exceeds 250, the blackness may decrease (L ^* value increases). A more preferred intensity ratio is 45 to 245, and even more preferably 50 to 240. In the present invention, a small amount of spinel phase may be contained as long as the hematite phase and the bixbite phase satisfy the above range.

The heat-resistant black powder according to the present invention has a blackness (L ^* value) of 25.0 or less. When the blackness (L ^* value) exceeds 25.0, it is not preferable as a black pigment. More preferable blackness (L ^* value) is 24.5 or less, and even more preferably 20 to 24.

The a ^* value of the heat-resistant black powder according to the present invention is preferably −2 to +5. When the a ^* value is out of the above range, it is difficult to say a black pigment. More preferably, it is −1 to +2.

The b ^* value of the heat-resistant black powder according to the present invention is preferably -5 to +5. When the b ^* value is out of the above range, it is difficult to say a black pigment. More preferably, it is −4 to +2.

The saturation c ^* value of the heat-resistant black powder according to the present invention is preferably 2.5 or less, more preferably 0.1 to 2.0.

The heat-resistant black powder according to the present invention contains Mg and / or Ca and is a black pigment close to achromatic color with relatively low a ^* value, b ^* value, and c ^* value.

  The average particle size of the heat-resistant black powder according to the present invention is preferably 0.02 to 5.0 μm. When the average particle diameter of the black powder exceeds 5.0 μm, the particle size is too large and the coloring power is reduced. When the average particle size is less than 0.02 μm, dispersion in the vehicle may be difficult. More preferably, it is 0.025-4.0 micrometers, More preferably, it is 0.04-2.0 micrometers.

The BET specific surface area of the heat-resistant black powder according to the present invention is preferably 1 to 50 m ² / g. When the BET specific surface area is less than 1 m ² / g, the particles are coarse or the particles are sintered between the particles and the coloring power is reduced. On the other hand, when the BET specific surface area exceeds 50 m ² / g, aggregation is likely to occur due to an increase in intermolecular force due to the refinement of particles, so that it is difficult to uniformly coat the particle surface with a surface treatment agent. More preferably, it is 1.5-25 m < ² > / g, More preferably, it is 1.8-15 m < ² > / g.

  The shape of the particles of the heat-resistant black powder according to the present invention is not limited to a specific shape, and is spherical, granular, octahedral, hexahedral, polyhedral, etc., acicular, spindle, rice, etc. Needle-like particles and plate-like particles can be used. Considering the dispersibility of the resulting black pigment, spherical particles and granular particles are preferred.

  The heat-resistant black powder according to the present invention may further contain Al in the range of 0.01 to 5.0% by weight.

  In the heat-resistant black powder according to the present invention, the surface of the powder is coated with one or more compounds selected from Si, Al, Zr, Ti, Zn, and P or various surface treatment agents such as an organic surface treatment agent. Can be used.

  Next, a method for producing a heat-resistant black powder according to the present invention will be described.

In addition, the heat-resistant black powder according to the present invention comprises an iron compound, a manganese compound, a magnesium compound and / or a calcium compound, an Fe / Mn ratio (molar ratio) of 1.0 to 10.0, and the magnesium compound is MgCO _3. The mixing ratio (MgCO ₃ amount / (iron compound + manganese compound + magnesium compound)) as 0.01 to 10.0 wt%, or the calcium compound as CaCO ₃ mixing ratio (CaCO ₃ amount / (iron compound + manganese) Compound + calcium compound)) is mixed so as to be 0.01 to 10.0 wt%, and the resulting mixture can be obtained by firing at a temperature range of 830 to 1000 ° C.

  The iron compound, manganese compound, magnesium compound, and calcium compound may be appropriately selected from oxides, hydroxides, carbonates, nitrates, sulfates, chlorides, and the like of each element. Etc. can be used.

  The mixing of the starting materials is not particularly limited as long as the starting materials can be uniformly mixed, and may be wet mixing or dry mixing. Also, wet synthesis may be used.

  The heating and baking temperature is preferably 830 to 1000 ° C, more preferably 850 to 950 ° C. The heating atmosphere is not particularly limited, but can be performed in the air.

  The powder after heating may be washed and pulverized according to a conventional method if necessary.

  In the present invention, in order to control the ratio of the strength ratio of the (104) plane of the hematite phase of the composite oxide to the strength ratio of the (222) plane of the bixbite phase, the composition ratio of the elements is controlled and the composition is controlled. Accordingly, it is necessary to control the heating and baking temperature. When the baking temperature is lowered, the hematite phase increases and the bixbite phase tends to decrease relatively. On the other hand, when the baking temperature is increased, the magnetite phase increases and the bixbite phase tends to decrease relatively. By adding and baking an aluminum compound, a magnesium compound, and a calcium compound, it becomes possible to suppress the formation of a spinel phase and to perform baking at a high temperature.

  In the present invention, the particle surface of the heat-resistant black powder may be coated with one or more compounds selected from Si, Al, Zr, Ti, Zn, and P. The surface treatment method may be performed according to a conventional method such as a wet method or a dry method. For example, in the wet method, one or more soluble compounds selected from Si, Al, and Zr are added to and mixed with a slurry of heat-resistant black powder that has been wet-dispersed while adjusting the pH with an acid or alkali. The dry method is a method in which heat-resistant black powder is coated with one or more coupling agents selected from Si, Al, Zr, and Ti in an apparatus such as a Henschel mixer.

  Next, a paint containing the heat-resistant black powder according to the present invention will be described.

  The blending ratio of the heat-resistant black powder in the paint according to the present invention can be used in the range of 0.5 to 100 parts by weight with respect to 100 parts by weight of the paint base material, and the handling property of the paint is taken into consideration. For example, it is preferably 1.0 to 100 parts by weight.

  As the paint constituent base material, a resin, a solvent, and if necessary, fats and oils, an antifoaming agent, an extender pigment, a drying accelerator, a surfactant, a curing accelerator, an auxiliary agent and the like are blended.

  As the resin, the solvent, or the solvent for the water-based paint, those usually used for solvent-based paint or oil-based printing ink may be used.

  Next, the resin composition containing the heat-resistant black powder according to the present invention will be described.

  The blending ratio of the heat-resistant black powder in the resin composition according to the present invention can be used in the range of 0.01 to 200 parts by weight with respect to 100 parts by weight of the resin, and the handling property of the resin composition is taken into consideration. Thus, the amount is preferably 0.05 to 150 parts by weight, more preferably 0.1 to 100 parts by weight.

  As a constituent substrate in the resin composition according to the present invention, a heat-resistant black powder and a known thermoplastic resin, and additives such as a lubricant, a plasticizer, an antioxidant, an ultraviolet absorber, and various stabilizers as necessary. Is blended.

  What is necessary is just to use what is used normally as resin.

  The resin composition according to the present invention is obtained by mixing a resin raw material and a heat-resistant black powder in advance, and then applying a strong shearing action under heating using a kneader or an extruder, The aggregate is broken and the heat-resistant black powder is uniformly dispersed in the resin composition, and then molded into a shape according to the purpose and used.

  The resin composition according to the present invention can also be obtained via a master batch pellet.

  In the master batch pellet in the present invention, the binder resin as a constituent substrate of the resin composition, the heat-resistant black powder and various additives are mixed with a mixer if necessary, and then a well-known single-screw kneading extrusion. It is manufactured by kneading and molding after a kneading machine or twin-screw kneading extruder or cutting, or by crushing or molding and cutting the kneaded material obtained by kneading the above mixture with a Banbury mixer, pressure kneader or the like. The

  As for the supply of the binder resin and the heat-resistant black powder to the kneader, each of them may be supplied at a predetermined ratio, or a mixture of both may be supplied.

  The master batch pellet in the present invention has an average major axis of 1 to 6 mm, preferably 2 to 5 mm. The average minor axis is 2 to 5 mm, preferably 2.5 to 4 mm. When the average major axis is less than 1 mm, the workability at the time of producing the pellet is poor, which is not preferable. When the thickness exceeds 6 mm, the difference from the size of the binder resin for dilution is large, and it becomes difficult to sufficiently disperse. Moreover, the shape can be various, and can be indefinite and spherical, cylindrical, flakes, and the like.

  As the binder resin used for the master batch pellet in the present invention, the same resin as the resin for resin composition can be used.

  The composition of the binder resin in the masterbatch pellet may be the same resin as the diluent binder resin or a different resin, but if different resins are used, What is necessary is just to determine in consideration of the various characteristics determined by the compatibility.

  The amount of the heat-resistant black powder blended in the master batch pellet is preferably 1 to 200 parts by weight with respect to 100 parts by weight of the binder resin.

  A typical embodiment of the present invention is as follows.

  The crystal structure of the heat-resistant black powder is measured with an “X-ray diffractometer RINT2500” (manufactured by Rigaku Denki Kogyo Co., Ltd.), corrected by smoothing, background removal, Kα removal, etc. with the attached program. A search was performed to determine the d value and the peak intensity. The intensity ratio of the (222) plane of the bixbite phase and the intensity ratio of the (311) plane of the spinel phase were determined with respect to the intensity ratio of the (104) plane of the hematite phase.

  For the content of metal elements (Fe, Mn, Mg, Ca, Al) in heat-resistant black powder and the content of Al in the Fe raw material, an ICP emission spectroscopic analyzer iCAP-6500DUO (manufactured by Thermo Electron Co., Ltd.) is used. I asked. Moreover, it converted into molar ratio and calculated | required Fe / Mn ratio (molar ratio).

The hue (L ^* value, a ^* value, b ^* value) of the heat-resistant black powder was prepared by mixing 0.5 g of a sample and 0.5 ml of castor oil with a Hoover-type Mahler to form a paste. .5 g was added, kneaded and converted into a paint, and an application piece (coating thickness: about 30 μm) applied on cast-coated paper using a 150 μm (6 mil) applicator was produced. The coating piece was measured using a “color difference meter CR-300” (manufactured by Konica Minolta Sensing Co., Ltd.), and the color index (L ^* value, a ^* value, b ^* value) according to JIS Z 8729. ). Further, the c ^* value (saturation) was calculated based on the following formula. The closer the c ^* value is to 0, the closer it is to an achromatic color.
c ^* value = {(a ^* value) ² + (b ^* value) ² } ^1/2

The heat resistance of the heat-resistant black powder is as follows: 10 g of a sample is put in a magnetic crucible, heat-treated at 800 ° C. for 2 hours using an electric furnace, allowed to cool, the color of the sample powder is measured, and before heat treatment It was obtained by measuring the change in hue after and was expressed by ΔE expressed by the following formula based on the measured color before the heat treatment. The smaller ΔE, the smaller the change in hue and the better the heat resistance.
ΔE = {(ΔL) ² + (Δa) ² + (Δb) ² } ^1/2
Where ΔL: difference in L ^* value between samples to be compared Δa: difference in a ^* value between samples to be compared Δb: difference in b ^* value between samples to be compared

  The magnetization value was indicated by a value measured by applying an external magnetic field of 796 kA / m (10 kOe) with a “sample vibration magnetometer BHV-35” (manufactured by Riken Denshi Co., Ltd.).

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

Example 1
Magnetite (Toda Kogyo Co., Ltd.) 452 g (75.3 wt%) and trimanganese tetroxide 147 g (24.5 wt%) are mixed with calcium carbonate 1.4 g (0.24 wt%, purity 99 wt%) to produce an electric furnace And baked at 990 ° C. for 2 hours. The fired product was pulverized to obtain a black powder.

  The obtained powder had a strength ratio of the bixbite phase 147 to the hematite phase 100. From the ICP measurement, the Ca content was 0.09 wt% and Fe / Mn (molar ratio) = 3.0.

The obtained powder had a magnetization value of 0.7 Am ² / kg and a specific surface area of 1.7 m ² / g. In addition, the hue of the coating piece made into a paint with clear lacquer is black with L ^* value of 24.6, a ^* value of 0.6, b ^* value of -0.3, and converted c ^* value of 0.6. It was a powder.

The hue of the powder obtained by heating the obtained powder in an electric furnace at 800 ° C. for 2 hours has an L ^* value of 24.6, an a ^* value of 0.8, and a b ^* value of −0.2. The heat resistance ΔE was 0.2, and the black powder was excellent in heat resistance.

Example 6
Magnetite (manufactured by Toda Kogyo Co., Ltd.) 437 g (72.9 wt%) and trimanganese tetroxide 142 g (23.7 wt%) are mixed with magnesium carbonate 20 g (3.4 wt%, purity 99.9 wt%). And baked at 940 ° C. for 6 hours. The fired product was pulverized to obtain a black powder.

  The obtained powder had a strength ratio of the bixbite phase 71 and the spinel phase 6 to the hematite phase 100. From the ICP measurement, the Mg content was 0.77 wt% and Fe / Mn (molar ratio) = 3.0.

The obtained powder had a magnetization value of 1.9 Am ² / kg and a specific surface area of 2.0 m ² / g. In addition, the hue of the coated piece made into a paint with clear lacquer has an L ^* value of 24.4, an a ^* value of 0.7, a b ^* value of -0.2, a converted c ^* value of 0.7, and heat resistance. It was a black powder having a property ΔE of 0.3.

Examples 2-5, 7, 8
A black powder was obtained in the same manner as in Examples 1 and 6, except that the mixing ratio of magnetite, trimanganese tetroxide, calcium carbonate, and magnesium carbonate and the firing temperature were changed.

Example 9
442 g (73.8 wt%) of magnetite having an average particle size of 0.28 μm, an Al content of 0.23 wt% and an Mg content of 0.15 wt%, and 143 g (23.8 wt%) of trimanganese tetraoxide and calcium carbonate 14 g (2.3 wt%, purity 99 wt%) was mixed and baked in an electric furnace at 980 ° C. for 8 hours. The fired product was pulverized to obtain a black powder.
The obtained powder had a strength ratio of the bixbite phase 163 to the hematite phase 100. From ICP measurement, Fe / Mn (molar ratio) = 3.0, Ca content 0.96 wt%, Mg content 0.10 wt%, Al content 0.15 wt%.
The obtained black powder had a magnetization value of 1.6 Am ² / kg and a specific surface area of 1.9 m ² / g. In addition, the hue of the coated piece made of clear lacquer is L ^* value 24.2, a ^* value 0.7, b ^* value -0.4, converted c ^* value 0.8, heat resistance It was a black powder having a property ΔE of 0.3.

Comparative Example 1
A powder was obtained in the same manner as in Example 1 except that the iron raw material, the size, the mixing ratio with trimanganese tetroxide and the firing temperature were changed.

The obtained powder had a strength ratio of the bixbite phase 15 to the hematite phase 100. In addition, the hue of the coating piece made into a paint with clear lacquer has an L ^* value of 25.5, an a ^* value of 5.0, a b ^* value of 3.2, a c ^* value of 5.9, and a heat resistance ΔE of It was 1.5, and it was hard to say black, and it was a powder having low heat resistance.

Comparative Examples 2-6
A powder was obtained in the same manner as in Comparative Example 1 except that the type and size of the iron raw material, the mixing ratio with trimanganese tetroxide and the firing temperature were changed.

Comparative Examples 7 and 8
A black powder was obtained in the same manner as in Examples 1 and 6, except that the mixing ratio of magnetite, trimanganese tetroxide, calcium carbonate, and magnesium carbonate and the firing temperature were changed.

  Table 1 shows the production conditions of the heat-resistant black powder, and Table 2 shows the characteristics of the obtained heat-resistant black powder.

  The heat-resistant black powder according to the present invention is suitable as a colorant for a paint or a resin composition because of excellent heat resistance and little change in hue (blackness) even at high temperatures. Applications include mainly automobiles and motorcycle mufflers, engine covers, plant indoor and outdoor heating equipment, incinerators, chimneys, kitchen equipment, rocket launch pads, and various paints that require heat resistance and appearance. Useful.

Claims (7)

A heat-resistant black powder made of a composite oxide containing Fe, Mn, Mg, or Ca, having a change in hue of a heat resistance test at 800 ° C. of 0.5 or less, and a magnetization value of 2.0 Am ² In the X-ray diffraction spectrum of the heat-resistant black powder, the intensity ratio of the (222) plane of the bixbite phase is 45 to 250 with respect to the intensity ratio of the (104) plane of the hematite phase. A heat-resistant black powder characterized by that. The heat-resistant black powder according to claim 1, wherein the Mg content is 0.01 to 5.0% by weight, or the Ca content is 0.01 to 5.0% by weight. body. The heat-resistant black powder according to claim 1 or 2, wherein the Fe / Mn (molar ratio) is 1.0 to 10.0. The heat-resistant black powder according to any one of claims 1 to 3, wherein the blackness (L ^* value) is 25.0 or less. Iron compound, manganese compound, magnesium compound and / or calcium compound, Fe / Mn ratio (molar ratio) is 1.0 to 10.0, the mixing ratio of the magnesium compound as MgCO ₃ (MgCO ₃ weight / (iron compound + manganese compound + magnesium compound)) is 0.01~10.0wt%, or the mixing ratio of the calcium compound as CaCO ₃ (CaCO ₃ weight / (iron compound + manganese compound + calcium compound)) is 0.01 to 10. The method for producing a heat-resistant black powder according to any one of claims 1 to 4, wherein the mixture is mixed so as to be 0 wt%, and the obtained mixture is fired in a temperature range of 830 to 1000 ° C. The coating material which mix | blended the heat-resistant black powder in any one of Claims 1 thru | or 4 in the coating-material base material. The resin composition colored using the heat-resistant black powder in any one of Claims 1 thru | or 4.