JPH0461032B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a colored mica titanium pigment in which the surface of mica particles is coated with titanium dioxide, lower titanium oxide, or lower titanium oxide. The colored mica titanium pigment of the present invention has pearlescent luster and has excellent pigment properties such as safety, stability, light resistance, acid resistance, alkali resistance, solvent resistance, and heat resistance. It is. Conventional mica titanium pigments are from Cosmetic Raw Materials Standards Supplementary Commentary 6th Edition (published in 1981, Yakuji Nippo) P54~
As described on page 57, it has pearlescent luster and various interference colors by forming a titanium dioxide layer on the surface of fine flaky mica. Vacuum deposition processing is also available as a manufacturing method, but Dupont's patent (Tokuko Showa) 43−
A common method is to hydrolyze an aqueous solution of an inorganic acid salt of titanium (for example, titanyl sulfate) in the presence of mica to precipitate hydrated titanium dioxide on the mica surface, and then heat it, as shown in Japanese Patent Publication No. 25644. .
The mica used is generally muscovite mica, but biotite or the like may also be used in some cases. In addition, mica is pulverized with water in advance and the particle size is made uniform using a sieve. The produced mica titanium pigment exhibits various interference colors depending on the thickness of the titanium dioxide coating layer on the mica particle surface. The interference color shows that when the amount of titanium dioxide is between 10 and 26% by weight of the product,
Usually silvery, but 26-40% golden, 40-50%
Red, in the direction of increasing titanium dioxide layer in the range of
The color changes to blue and green, and at 50 to 60%, high-order interference colors are obtained. Table 1 shows the relationship between interference color and the thickness of the titanium dioxide layer on the surface of the mica particles. Table 1 (Interference colors) (Geometric thickness of TiO ₂ ) [mμ] Silver 20-40 Light gold 40-90 Gold 40-90 Red 90-110 Violet 110-120 Blue 120-135 Green 135-155 2nd order gold 155-175 2nd order violet 175-200 Although these mica titanium pigments have pearlescent luster and various interference colors, the appearance color is always close to white, and it is difficult to obtain one that exhibits a bright appearance color. Not yet. Therefore, in order to produce various external colors, conventionally,
Colored pigments such as iron oxide, navy blue, chromium oxide, carbon black, and carmine were added to the mica titanium pigments produced. The safety, stability, light resistance, acid resistance, alkali resistance, solvent resistance, heat resistance, etc. of these colored mica titanium pigments are largely due to the properties of the colored pigments added.For example, blue mica with navy blue added. Titanium-based pigments discolor in alkaline solutions, and red mica titanium-based pigments containing carmine discolor and deteriorate when exposed to light. On the other hand, the carcinogenicity of 3,4-benzpyrene, which may be mixed into carbon black, such as black mica titanium pigments containing carbon black and green mica titanium pigments containing chromium oxide, There are many safety concerns, such as the oral toxicity of chromium. Furthermore, since the colored mica titanium pigments contain colored pigments, they also have drawbacks such as color separation in the solvent. As a result of intensive research in order to improve the above-mentioned drawbacks, the present inventors have discovered that by coating the surface of mica particles with titanium dioxide and lower titanium oxide, or with lower titanium oxide, we have succeeded in improving the conventional mica titanium-based pigment or colored pigment. It has a color tone that is equal to or more vivid than colored mica titanium pigments, and has pearlescent safety, stability, light resistance, acid resistance, alkali resistance, solvent resistance, and heat resistance. It was discovered that a colored mica titanium pigment can be obtained, and the present invention was completed based on this knowledge. That is, the present invention is a colored mica titanium pigment in which the mica surface is coated with titanium dioxide and lower titanium oxide, or lower titanium oxide. In the present invention, the mica is composed of flaky mica, and is preferably a colored mica titanium pigment having an appearance color similar to the interference color. Furthermore, it is preferable that the pigment be a colored mica titanium-based pigment characterized in that the geometric layer thickness (hereinafter simply referred to as layer thickness) of total titanium oxide on the mica surface is 40 mμ or more. Further, it is preferable that the total titanium oxide/mica weight ratio is 35/65 or more. Next, the configuration of the present invention will be explained in detail. Any type of mica may be used in the present invention, and commercially available muscovitemica is generally used, but biotite or the like may also be used in some cases. The particle size is not particularly limited, but the particle size of commercially available mica is 1
~50μ, and among these, those with a small particle size and a particle shape as flat as possible are more likely to exhibit beautiful color tone and pearlescent luster than when the colored mica titanium pigment of the present invention is used. In addition, the low-order titanium oxide in the present invention is a titanium compound with a lower valence than tetravalent titanium, and is a titanium oxide whose general formula is Ti _o O _2o-1 (n is a positive integer); It is a general term that includes titanium oxide nitride in which nitrogen is contained in the titanium oxide mentioned above. The colored mica titanium pigment of the present invention is a pigment in which the surface of mica particles is coated with titanium dioxide, lower titanium oxide, or lower titanium oxide, and various methods can be used to produce this pigment. be able to. For example, commercially available mica titanium pigment
℃ ~ 1000 ℃, preferably 700 ℃ ~ 900 ℃ by one or more gases having reducing power such as hydrogen gas and ammonia gas, or these gases having reducing power and helium gas, argon gas , a method of heating and reducing with a mixed gas with an inert gas such as nitrogen gas, a method of mixing titanium dioxide with a commercially available mica titanium pigment, and heating and reducing the mixture by the above method, or Examples of the method include mixing titanium metal with a mica titanium pigment and reducing the mixture by heating at 500°C to 1000°C, preferably 700°C to 900°C, under vacuum.
Furthermore, DuPont's patent (Special Publication No. 43-25644)
An aqueous solution of an inorganic acid salt of titanium (e.g., titanyl sulfate), such as that found in 700
By one or more gases having reducing power such as hydrogen gas and ammonia gas at a temperature of ℃ to 900℃, or by combining these gases with reducing power and inert gas such as helium gas, argon gas, nitrogen gas, etc. Either by heating and reducing with a gas mixture with mica particles, or by precipitating hydrous titanium dioxide on the surface of mica particles, heating to generate mica titanium, which is reduced in the same manner as the commercially available mica titanium pigments. Also good. Furthermore, the reduction method is not limited to the method using a reducing gas such as hydrogen gas or ammonia gas as described above, but also a method in which mica titanium is reduced using a reducing flame such as hydrogen gas, or a method in which mica is reduced with a titanium salt. For example, it is also possible to suspend the titanium tetrachloride solution and oxidize and decompose this suspension in a flame of a mixed gas of air and hydrogen. In other words, the colored mica titanium pigment of the present invention is a colored mica titanium pigment in which the surface of mica particles is coated with titanium dioxide, lower titanium oxide, or lower titanium oxide, and can be produced by any known method. This method may be used, and there is no particular restriction. The amount of titanium dioxide and lower titanium oxide or lower titanium oxide coating the mica can be varied within a wide range, and is usually about 100 parts by weight of mica (100 parts by weight).
Titanium dioxide can be coated in amounts of 0 to 60 parts by weight, and lower titanium oxides can be coated in amounts of 0.01 to 60 parts by weight. If the amount of lower titanium oxide is less than 0.01 part by weight per 100 parts by weight of mica, the resulting titanium mica will not be colored.
If it exceeds 60 parts by weight, the properties of the mica will be extremely poor and the particles will agglomerate strongly. This property holds true even when the amount of titanium dioxide exceeds 60 parts by weight per 100 parts by weight of mica. In the present invention, total titanium oxide (titanium dioxide + lower titanium oxide: there is almost no change in the weight ratio with mica or layer thickness before and after reduction)
If the geometric layer thickness is less than 40 mμ, the appearance color itself tends to be achromatic from silvery gray to black, and is unlikely to be colored. In addition, in the present invention, when the layer thickness is 40 mμ or more, an appearance color similar to the interference color can be obtained, and specific products exhibit an interference color of gold, red, violet, blue, or green. A product having an appearance color similar to that of the product can be obtained. In addition, in the case of commonly used mica, in order to obtain a geometric layer thickness of 40 mμ or more as described above, it is preferable that the total titanium oxide/mica weight ratio is 35/65 or more. Next, the present invention will be explained by examples. Parts in the examples represent parts by weight. Example 1 50 parts of mica was added to 500 parts of ion-exchanged water and thoroughly stirred to be uniformly dispersed. 208.5 parts of a titanyl sulfate aqueous solution having a concentration of 40% by weight was added to the obtained dispersion, and the mixture was heated and boiled for 6 hours while stirring. After cooling, it was washed with water and calcined at 900°C to obtain 90 parts of mica coated with titanium dioxide (titanium mica). Next, the obtained titanium mica was subjected to a reduction treatment at 800° C. for 4 hours under an ammonia gas flow at a flow rate of 3/min, and after cooling, the powder was recovered. The obtained powder had a bright blue pearlescent appearance and interference color. The surface condition of the blue mica titanium pigment particles of this product is as shown in the scanning electron micrograph of FIG. According to this, it is possible to observe that the surface of each particle of the blue mica titanium pigment, which is a product, is sufficiently covered with fine particles. In addition, the X-ray diffraction diagram (Cu-Kα ray) of the blue mica titanium pigment that is this product is as shown in Figure 2, and it shows that in addition to the diffraction peak of mica, the diffraction angle (Bragg angle 2θ) A peak is observed around 25.3°. This corresponds to 101, the strongest peak of anatase titanium dioxide. In addition, a slightly broad peak is observed near 2θ = 43.3°, but this peak corresponds to the strongest peak of 200 in titanium oxynitride, which contains nitrogen (N) in titanium monoxide (TiO). It can be seen that the mica particle surface of the blue mica titanium pigment, which is the product obtained in the example, is coated with titanium dioxide and titanium oxynitride. Incidentally, FIG. 4 shows an X-ray diffraction diagram of titanium dioxide-coated mica that has not been subjected to reduction treatment. In the diffraction diagram shown in the same figure, the peak of titanium oxynitride (2θ = 43.3°) is hardly recognized, and the product of this example and the titanium dioxide-coated mica that has not been subjected to reduction treatment are completely different products. That is understood. Furthermore, the amounts of titanium dioxide and lower titanium oxide coating the mica particle surface were determined by the method shown below. (1) The sample before reduction treatment and the sample after reduction treatment were each pulverized using an agate ball mill to render mica amorphous. The intensity of the diffraction line of titanium dioxide and the diffraction line of lower order titanium oxide was determined by the powder measurement method of X-ray diffraction (Cu-Kα rays) of the sample, and the intensity was calculated based on the mixing ratio of mica and titanium dioxide determined separately. The amounts of titanium dioxide and lower titanium oxide were determined by comparing with a calibration curve of diffraction intensity for which the mixing ratio of titanium dioxide and lower titanium oxide was known. (2) Since lower titanium oxide is completely converted to titanium dioxide by firing in the atmosphere, the amount of lower titanium oxide was determined by gravimetric analysis of the sample that had been subjected to the reduction treatment. i.e. 20ml
Approximately 5 g of the sample was accurately weighed into a magnetic crucible and heat-treated at 800°C for 4 hours in the atmosphere. After cooling, the weight increase was accurately measured, and the amount of lower titanium oxide was determined from the weight increase. When the amounts of titanium dioxide and lower titanium oxide in the blue mica titanium pigment product are determined by the above method, the blue mica titanium pigment product is 6.4 parts by weight per 100 parts by weight of mica. This is a blue mica titanium pigment made by coating the mica surface with 33.6 parts by weight of titanium dioxide and 33.6 parts by weight of lower titanium oxide. As mentioned above, since the pigment according to this example has an interference color similar to the appearance color, that is, a blue interference color, Table 1 suggests that the layer thickness is 120 to 135 mμ. Example 2 50 parts of mica was added to 500 parts of ion-exchanged water and thoroughly stirred to be uniformly dispersed. 312.5 parts of a titanyl sulfate aqueous solution having a concentration of 40% by weight was added to the obtained dispersion, and the mixture was heated and boiled for 6 hours while stirring. After cooling, it was washed with water and fired at 900°C to obtain 100 parts of mica (mica titanium) whose surface was coated with titanium dioxide. Next, the obtained mica titanium was poured at a flow rate of 1/min.
Reduction treatment was performed at 800° C. for 4 hours under a mixed gas flow of ammonia gas and nitrogen gas at a flow rate of 3/min, and after cooling, the powder was collected. The obtained powder exhibited a bright green pearlescent appearance and interference color. The X-ray diffraction pattern (Cu-Kα line) of this product, a green mica titanium pigment, is shown in Figure 3. According to this, as in Example 1, in addition to the diffraction peak of mica, the strongest peak (101) of anatase-type titanium dioxide is found near the diffraction angle (Bragg angle 2θ) of 25.3°.
In addition, the strongest peak (200) of titanium oxynitride, which contains nitrogen (N) in titanium monoxide (TiO), which is slightly broad around 2θ = 43.3°, is observed, and the green mica obtained in this example It can be seen that the mica particle surface of the titanium-based pigment is coated with titanium dioxide and titanium oxynitride. Further, the amounts of titanium dioxide and lower titanium oxide coated on the surface of the mica particles were determined by the same method as in Example 1. As a result, it was found that the green mica titanium pigment of this product was coated with 100 parts by weight of mica, 3.8 parts by weight of titanium dioxide, and 46.2 parts by weight of lower titanium oxide. As mentioned above, since the pigment according to this example has a green interference color, from Table 1 above, 135~
It is suggested that the layer thickness is 155mμ. Example 3 50 parts of mica was added to 500 parts of ion-exchanged water and thoroughly stirred to be uniformly dispersed. 208.5 parts of a titanyl sulfate aqueous solution having a concentration of 40% by weight was added to the obtained dispersion, and the mixture was heated and boiled for 6 hours while stirring. After cooling, filter and wash with water, dry at 100℃, mica titanium 90
I got the department. The product was subjected to a reduction treatment at 900° C. for 3 hours under an ammonia gas flow at a flow rate of 3/min, and after cooling, 90 parts of powder was recovered. The obtained powder had a bright blue pearlescent appearance and interference color. In addition, the amount of titanium dioxide and lower titanium oxide coating the mica particle surface is 4.6 parts by weight for 100 parts by weight of mica that is the core of titanium dioxide, and the same amount for lower titanium oxide.
It was 35.4 parts by weight. Since the pigment according to this example has a blue interference color, Table 1 suggests that the layer thickness is 120 to 135 mμ. Example 4 50 parts of mica was added to 500 parts of ion-exchanged water and thoroughly stirred to be uniformly dispersed. 312.5 parts of a titanyl sulfate aqueous solution having a concentration of 40% by weight was added to the obtained dispersion, and the mixture was heated and boiled for 6 hours while stirring. After cooling, it was washed with water and calcined at 900°C to obtain 100 parts of mica coated with titanium dioxide (mica titanium).
Next, 1.2 parts of metallic titanium was mixed with 100 parts of the obtained mica titanium, and the mixture was mixed using an oil diffusion pump.
The mixture was heated and reduced at 800° C. for 4 hours at a vacuum level of 10 ⁻³ torr or less. After cooling, 101.2 parts of powder was obtained. The obtained powder was a bright blue-green powder with pearlescent appearance and interference color. In addition, the amounts of titanium dioxide and lower titanium oxide coating the mica in the blue-green mica titanium pigment of this product were determined by quantitative methods (1) and (2) described in Example 1. Titanium dioxide per 100 parts by weight of mica
It was found that the amount of titanium oxide was 40.5 parts by weight, and the amount of lower titanium oxide was 9.5 parts by weight. Since the pigment according to this example has a blue-green interference color, Table 1 suggests that the layer thickness is 130 to 140 mμ. Examples 5 to 8 Fifty parts of each of four types of commercially available (manufactured by Marl Inc., USA) mica titanium pearlescent pigments with interference colors were taken and each was reduced by changing the type of reducing gas, gas flow rate, reduction temperature, and reduction time. . After cooling, 50 parts of product was obtained.
The color and interference color of the obtained powder were observed with the naked eye, and the color tone was measured by the powder cell method using Color Analyzer 607 (Hitachi) (Hue (H). Brightness (V)./Saturation (C). )). Further, the amounts of titanium dioxide and lower titanium oxide were determined by quantitative methods (1) and (2) described in Example 1. The results are shown in Table 2. Examples 9 to 12 Take 50 parts each of four types of commercially available (manufactured by Marl Inc., USA) mica titanium pearlescent pigments with interference colors, change the amount of metallic titanium mixed, and use the mixture and a diffusion pump to produce 10 ^- 4 at 800℃ with a vacuum level of ³ torr or less
The mixture was heated and reduced for a period of time. After cooling, the color of the powder obtained,
A color analyzer that observes interference colors with the naked eye and determines the color tone.
607 using the powder cell method (hue (H).
Brightness (V). /Saturation (C)).

[Table] Furthermore, the amounts of titanium dioxide and lower titanium oxide were determined by quantitative methods (1) and (2) described in Example 1. The results are shown in Table 3.

[Table] In Examples 5 to 12, the interference colors are gold to green, suggesting that the layer thickness is 40 to 155 mμ. Next, the pigment properties of the colored mica titanium pigments obtained in Examples 1 to 12 above were tested. For comparison, the pigment properties of a colored mica titanium based pearlescent pigment (a conventional mica titanium based pigment with a colored pigment added thereto) commercially available from Marl Corporation of the United States were tested in the same manner. The commercially available colored mica titanium pearlescent pigments for comparison were selected to correspond to the color tones of the colored mica titanium pigments produced in Examples 1 to 12. The results are shown in Table 4.

[Table] The composition of the commercially available product is shown in Table 5.

[Table] The test items are acid stability, alkali stability, light stability, thermal stability, and dispersion stability, and the test methods and test results are as follows. Acid stability test 1.5 g of the colored mica titanium-based pigment, which is a product of the present invention, and the commercially available colored mica titanium-based pearlescent pigment were each placed in a 50 ml test tube with a stopper.
After adding 30 ml of 2N hydrochloric acid aqueous solution and dispersing, the mixture was allowed to stand still in a test tube stand, and the color tone after 24 hours was observed with the naked eye. The results are shown in Table 6. As is clear from the results in Table 6, all of the colored mica titanium pigments that are products of the present invention were stable against acids, but all of the commercially available colored mica titanium pearlescent pigments were unstable and gradually deteriorated. After 24 hours, the commercially available Cloisonne Red turned white, and the colors of Cloisonne Gold, Cloisonne Blue, and Cloisonne Green became pale and whitish, and their pearlescent luster was extremely reduced. Thus, it can be seen that the colored mica titanium pigment, which is a product of the present invention, has excellent acid stability.

【table】

[Table] Alkali stability test 1.5 g of the colored mica titanium pigment, which is a product of the present invention, and the commercially available colored mica titanium pearlescent pigment were each placed in a 50 ml test tube with a stopper.
After adding and dispersing 30 ml of 2N caustic soda aqueous solution, the mixture was left to stand in a test tube rack and the color tone was observed with the naked eye after 24 hours. The results are shown in Table 7.

【table】

[Table] As is clear from the results in Table 7, the colored mica titanium-based pigment, which is the product of the present invention, is completely stable against alkalis, whereas the commercially available colored mica titanium-based pearlescent pigments are completely unstable. It was stable and gradually faded, and after 24 hours, the commercially available Cloisonne Red and Cloisonne Blue changed to white, and the colors of Cloisonne Gold and Cloisonne Green became pale and whitish, and their pearlescent luster was extremely reduced. Thus, it can be seen that the colored mica titanium pigment, which is a product of the present invention, has excellent alkali stability. Photostability test The colored mica titanium pigment that is a product of the present invention and the commercially available colored mica titanium pearlescent pigment are each mixed with talc (manufactured by Asada Seifun Co., Ltd.) in a ratio of 3:7, and 2.5 g of the mixture is 3mm thick each, 20 on each side
It was molded into a mm square aluminum medium plate, and was irradiated with a xenon lamp for 30 hours. The color tone after irradiation and the color tone before irradiation were measured using a color analyzer 607, and the color difference (ΔE) before and after irradiation was determined from the colorimetric values. The results are shown in Table 8.

【table】

[Table] As is clear from the results in Table 8, the color difference (ΔE) of the colored mica titanium pigment, which is the product of the present invention, is almost 0.5 or less before and after irradiation, and there is almost no difference in color tone with the naked eye. On the other hand, the commercial products Cloisonne Red and Cloisonne Gold had extremely large values of 35.3 and 18.0, respectively, and the change in color tone was obvious even to the naked eye. In addition, Cloisonne Green and Cloisonne Blue had a large color difference of 6.0 and 5.2, respectively, and it was observed that the color tone changed noticeably even with the naked eye. Thermal Stability Test The colored mica titanium pigment that is the product of the present invention and the commercially available colored mica titanium pearlescent pigment were tested.
Weighed 3g into a 20ml magnetic crucible and placed it in the atmosphere for 200 ml.
Heat treatment was performed for 2 hours under each temperature condition of 300°C, 300°C, 400°C, and 500°C. The color of the treated powder was measured using a color analyzer 607 to determine the color difference (ΔE) from the pigment before treatment. Table 9 shows the results of visual observation of color tone changes. As is clear from the results in Table 9, the colored mica titanium pigment, which is a product of the present invention, is stable with a color difference of 0.5 or less up to 400°C, with almost no change in color tone to the naked eye. When the temperature reaches 500℃, the color changes to yellowish white.
This is because the lower titanium oxide on the surface of the mica particles was oxidized and changed to titanium oxide. That is, it can be seen that the colored mica titanium pigment, which is the product of the present invention, is stable up to temperatures below 500°C. On the other hand, commercially available Cloisonne Red and Cloisonne Blue have a color difference of 3.2 and 3.5, respectively, at 200℃.
The color change is clearly visible even with the naked eye. When the temperature reaches 300℃, the color tone increases to 36.4 and 26.2, and the color changes from red to yellow-red and from blue to red-brown. In other words, Cloisonne Red and Cloisonne Blue are at 200℃.
The change in color tone indicates poor thermal stability. Cloisonné green has a color difference of 7.8 at 400℃
The color saturation decreases and the color changes to dark green. That is,
It is stable at temperatures below 400°C, but unstable at temperatures above that. As for Cloisonné Gold, even at 500℃, the chroma is slightly inferior.
The color difference is also less than 1.0 and it is highly stable.

【table】

[Table] Dispersion (color separation) stability test Put 1.0 g each of the colored mica titanium pigment, which is a product of the present invention, and the commercially available colored mica titanium pearlescent pigment into a 50 ml test tube with a stopper scale. to
Add 50ml of 0.2% by weight hexatalic acid aqueous solution,
Dispersion was carried out for 30 seconds using a Polytron, and this dispersion liquid was further dispersed using ultrasonic waves. After dispersion, the mixture was allowed to stand still in a test tube stand, and the dispersion state was observed with the naked eye immediately after, 5 minutes, 10 minutes, 30 minutes, and 1 hour after leaving it still. The results were as shown in Table 10. As is clear from the results in Table 10, the colored mica titanium pigment, which is a product of the present invention, is uniformly dispersed even after standing for 1 hour, whereas the commercial products Cloisonne Blue and Cloisonne Red are uniformly dispersed. , Sedimentation was observed after 5 minutes of standing, and the supernatant liquid was blue or red in color. this is,. This is simply due to the separation of the mixed navy blue and carmine. Sedimentation of Cloisonne Green was observed after 30 minutes of standing, and the supernatant liquid had a darker green color than the green color of the sedimented particles. This is simply due to the separation of the mixed chromium oxide. Cloisonne gold remained uniformly dispersed even after standing for 1 hour. As is clear from the above test results, the colored mica titanium pigment that is the product of the present invention is stable against acids, alkalis, and light, and is stable under heat at temperatures below 500°C. Stable up to temperatures of
Does not cause color change. Furthermore, it has excellent dispersibility, does not cause color separation, and has excellent pigment properties.

【table】

[Table] ×: Sediments completely with color separation.

[Brief explanation of the drawing]

Figure 1 is a scanning electron micrograph (30,000x) of the mica titanium pigment, which was the product obtained in Example 1, exhibiting a bright blue pearlescent color as well as an appearance color and an interference color. X-ray diffraction diagram (Cu-Kα ray) of the mica titanium pigment that is the product of Example 1
It is. Figure 3 shows the X-ray diffraction diagram (Cu-Kα
line). FIG. 4 is an X-ray diffraction diagram of titanium dioxide-coated mica that has not been subjected to reduction treatment.

Claims (1)

[Scope of Claims] 1. A colored mica titanium pigment whose mica surface is coated with titanium dioxide, lower titanium oxide, or lower titanium oxide. 2. The mica titanium pigment according to claim 1, wherein the mica is made of flaky mica and has an appearance color similar to an interference color. 3. The mica titanium pigment according to claim 2, characterized in that the geometric layer thickness of the total titanium oxide on the mica surface is 40 mμ or more. 4 In the mica titanium pigment described in claim 1, the total titanium oxide/mica weight ratio is 35/65.
A mica titanium pigment characterized by the above.