JP2016204398A - Inorganic pigment particle and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a black inorganic pigment particle excellent in dispersion stability.SOLUTION: Fluorine, carbon and oxygen are made to be present in a region to a depth of 7 nm from a surface of an inorganic pigment particle by contacting a gaseous mixture having fluorine gas concentration of 0.1 to 50 wt.% and nitrogen gas concentration of 50 wt.% with the surface of the inorganic pigment particle under a condition at 35 o 300°C. Amount of the fluorine present in the region to a depth of 7 nm from the surface of the inorganic pigment particle is less than 16 atom%, carbon amount is 80 atom% or more, oxygen amount is 0.1 atom% or more, and excellent dispersion stability is obtained.SELECTED DRAWING: None

Description

  The present invention relates to inorganic pigment particles suitable for various uses such as printing inks, paints, and inks for inkjet printers, and a method for producing the same.

  Pigment particles using carbon powder are widely used in printing inks and paints. Moreover, in order to improve the dispersibility of a pigment particle, the technique which fluorinates a carbon-type particle | grain is known (patent document 1 etc.).

JP-A-6-256008

In the above-described pigment particles, since fluorination has progressed too much, the particle surface becomes hydrophobic and dispersibility is not good. In addition, although black carbon-based particles are used, black ink cannot be obtained because white carbon fluoride (CF ₄ ) is generated.

  Accordingly, an object of the present invention is to provide inorganic pigment particles having superior dispersion stability as compared to conventional methods and a method for producing the same.

  In the inorganic pigment particles of the present invention, fluorine, carbon, and oxygen are present up to a depth of 7 nm from the surface of the inorganic pigment particles, and the amount of fluorine present up to a depth of 7 nm from the surface of the inorganic pigment particles is less than 16 atom%. Yes, the carbon content is 80 atom% or more, and the oxygen content is 0.1 atom% or more.

  By allowing fluorine, carbon, and oxygen to exist in the surface portion of the inorganic pigment particles and setting them within the above range, inorganic pigment particles having better dispersion stability than before can be obtained.

  Moreover, it is preferable that the amount of fluorine existing at a depth of 7 nm from the surface of the inorganic pigment particles is 7.0 atom% or less and the oxygen amount is 0.1 atom% or more. By setting the surface portion of the inorganic pigment particles to the above composition, good dispersibility can be maintained for a long time.

  Furthermore, the inorganic pigment particles are formed by subjecting the base particles to fluorine treatment, and the main component of the base particles is preferably a carbon material. Carbon materials are useful as inorganic pigment particles because they have good concealability, high coloring power, and high blackness. The substrate particles are preferably carbon black. While using general inorganic pigment particles, inorganic pigment particles having excellent dispersibility can be produced.

The method for producing inorganic pigment particles of the present invention includes:
A step of bringing a mixed gas containing fluorine and nitrogen into contact with the substrate particles,
The mixed gas has a fluorine gas concentration of 0.1 wt% or more and 50 wt% or less, a nitrogen gas concentration of 50 wt% or more, and the step is performed at 35 ° C. or more and 300 ° C. or less.
When the substrate particles are treated under the above conditions, the surface portion of the substrate particles can be mainly fluorinated. Thereby, since the inorganic pigment particle of the composition mentioned above can be manufactured, the pigment particle excellent in the dispersibility is obtained.

  Moreover, it is preferable that the said process is performed at 80 to 150 degreeC. By making processing temperature into the said range, it can suppress that the inside is fluorinated among base material particles. Thereby, particles excellent in dispersion stability can be obtained.

  Moreover, it is preferable that the fluorine gas concentration of the said mixed gas is 30 wt% or less. By setting the fluorine gas concentration within the above range, it is possible to mainly fluorinate the surface portion of the substrate particles and suppress fluorination inside the particles.

  Furthermore, the nitrogen gas concentration of the mixed gas is preferably 70 wt% or less. By setting the nitrogen gas concentration within the above range, the fluorine gas concentration in the mixed gas can be made a predetermined concentration or more. Thereby, the surface part can be reliably fluorinated among the substrate particles.

  Moreover, it is preferable that the said base material particle is carbon black. While using general inorganic pigment particles, inorganic pigment particles having excellent dispersibility can be produced.

  According to the present invention, fluorine, carbon, and oxygen are present on the surface portion of the inorganic pigment particles, and the amount of each element in the surface portion of the inorganic pigment particles is within a predetermined range, thereby making the dispersion stability more than conventional. Excellent inorganic pigment particles can be obtained.

It is a SEM photograph of inorganic pigment particles. It is a figure which shows the measurement result of the volume average particle diameter of an Example.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[Inorganic pigment particles]
The inorganic pigment particles of the present invention are obtained by subjecting substrate particles to fluorine treatment under predetermined conditions, and fluorine, carbon and oxygen are present on the surface of the inorganic pigment particles. Here, the “surface portion of the inorganic pigment particle” means “a portion from the surface of the inorganic pigment particle to a depth of 7 nm”. The “surface of the inorganic pigment particles” is the outermost layer portion of the inorganic pigment particles. In addition, the inorganic pigment particle | grains in this invention show the secondary particle which a plurality of primary particles gathered like FIG.

<Fluorine, oxygen>
By allowing fluorine to exist on the surface portion of the inorganic pigment particle, the surface portion of the inorganic pigment particle is uniformly charged in the dispersion medium. This action makes it possible to stably disperse the inorganic pigment particles in the liquid.

  Fluorine is preferably present on the surface of the inorganic pigment particles. Specifically, when fluorine exists from the surface of the inorganic pigment particles to a depth of 7 nm, the balance of the charge amount of the inorganic pigment particles is improved, and the dispersion of the inorganic pigment particles exhibits good dispersion stability.

  In addition, the present inventors have found that excellent dispersibility of inorganic pigment particles cannot be obtained only by fluorine, and the presence of oxygen is important. This is because oxygen forms a hydrophilic group. Further, it has been found that excellent dispersibility is exhibited by allowing fluorine and oxygen of a predetermined amount or more to be present on the surface portion of the inorganic pigment particles.

  The amount of fluorine existing from the surface of the inorganic pigment particles to a depth of 7 nm is preferably 16 atom% or less, and more preferably 7 atom% or less. If the amount of fluorine in the surface portion of the inorganic pigment particles is too large, the surface portion of the inorganic pigment particles will be hydrophobic, so the dispersibility in the liquid will be poor. Becomes better. The amount of fluorine existing from the surface of the inorganic pigment particle to a depth of 7 nm is preferably 0.1 atom% or more, and more preferably 0.4 atom% or more. If the amount of fluorine in the surface portion of the inorganic pigment particles is too small, the surface portion of the inorganic pigment particles is hardly charged and the dispersibility is poor. However, dispersibility is improved by setting the amount of fluorine within the above range.

  Further, the amount of oxygen existing from the surface of the inorganic pigment particles to a depth of 7 nm is preferably 2.0 atom% or less, and more preferably 1.7 atom% or less. If the amount of oxygen in the surface portion of the inorganic pigment particles is excessively large, the amount of fluorine is decreased and the dispersibility is deteriorated because it is hardly charged. However, dispersibility is improved by setting the amount of oxygen within the above range. Further, the amount of oxygen existing from the surface of the inorganic pigment particles to a depth of 7 nm is preferably 0.1 atom% or more, and more preferably 0.2 atom% or more. When the amount of oxygen in the surface portion of the inorganic pigment particles is too small, the hydrophilic group is decreased and the dispersibility is deteriorated. However, the dispersibility is improved by setting the above range.

  The total amount of fluorine, oxygen, and carbon from the surface of the inorganic pigment particles to a depth of 7 nm (surface portion of the inorganic pigment particles) is 100 atom% or less. Elements other than carbon may be included.

  Thus, by setting the surface portion of the inorganic pigment particles to a predetermined composition, the balance of the charge polarity of the surface portion of the inorganic pigment particles is improved, and the dispersibility in the liquid is improved. In particular, when the fluorine content is 7.0 atom% or less and the oxygen content is 0.1 atom% or more in the surface portion of the inorganic pigment particles, good dispersibility can be maintained over a long period of time. Moreover, dispersibility can be evaluated by specifying the amount of fluorine and the amount of oxygen in the surface portion of the inorganic pigment particles (from the surface of the inorganic pigment particles to a depth of 7 nm).

  On the other hand, the amount of fluorine existing from the depth of 7 nm to the depth of 17 nm from the surface of the inorganic pigment particles is preferably 10 atom% or less, more preferably 5 atom% or less, and even more preferably 2 atom% or less. If too much fluorine is present in this region, the polarity of the inorganic pigment particles becomes high, and the chargeability of the surface portion of the inorganic pigment particles becomes uneven. In this state, since the positive and negative charges are dispersed and present on the surface portion of the inorganic pigment particles, the inorganic pigment particles are not dispersed and may be suspicious. Moreover, when there is too much fluorine in this region, the specific gravity may increase and the dispersibility may decrease.

  Further, the amount of oxygen present from the depth of 7 nm to the depth of 17 nm from the surface of the inorganic pigment particles is preferably 1.8 atom% or less, and more preferably 1.0 atom% or less. If there is too much oxygen in this region, the specific gravity may increase and the dispersibility may decrease.

  Further, the amount of fluorine present from the depth of 17 nm to the depth of 27 nm from the surface of the inorganic pigment particles is preferably 5 atom% or less, and more preferably 1 atom% or less.

  As described above, although a predetermined amount of fluorine is present in the surface portion of the inorganic pigment particles, it is preferable that the amount of fluorine is small in the inorganic pigment particles or fluorine is not present in the particles. When the amount of fluorine inside the inorganic pigment particles increases, the specific gravity increases and the inorganic pigment particles themselves become heavy, and therefore, they are likely to precipitate in the dispersion medium. In the present invention, dispersibility is improved by setting the amount of fluorine in the inorganic pigment particles within the above range.

  The amount of each element such as the amount of fluorine and the amount of oxygen can be measured by, for example, X-ray electron spectroscopy (ESCA, XPS). Further, the amount of fluorine existing at a certain depth from the surface of the inorganic pigment particle is measured by the X-ray electron spectroscopy after removing a predetermined thickness from the surface of the inorganic pigment particle by performing an etching process or the like. be able to. A specific measurement method will be described in detail in the column of Examples.

  In addition, the fluorine which exists in the surface part of an inorganic pigment particle may couple | bond with the element in a base particle. For example, when a carbon material is employed as the base particle, a carbon-fluorine bond (including a semiionic weak carbon-fluorine bond that brings about hydrophilicity) may be formed on the surface portion of the inorganic pigment particle. The amount of fluorine can include carbon-fluorine bonded fluorine. Moreover, when oxygen is contained in the base particle or when oxygen is present on the surface of the base particle, a carbon-oxygen bond may be formed on the surface portion of the inorganic pigment particle. In this case, the fluorine amount in the surface portion of the inorganic pigment particles can include fluorine having a fluorine-oxygen bond.

  In addition, oxygen present on the surface portion of the inorganic pigment particles may be bonded to other elements (carbon-oxygen bond, fluorine-oxygen bond, etc.), but oxygen bonded to other elements may be included in the oxygen amount. Is possible.

<Base material particles>
As the base particles, those containing a carbon material, particularly those whose main component is a carbon material, are preferably used, and black carbon black, graphite or the like can be used. In addition, the carbon material is the main component of the base particle means that 80% or more of the base particle is carbon. Carbon materials are useful as inorganic pigment particles because they have good concealability, high coloring power, and high blackness.

  By subjecting the carbon material to fluorine treatment under predetermined conditions, fluorine, carbon, and oxygen are present on the surface portion of the inorganic pigment particles so that the total thereof is 100 atom% or less. In this case, the amount of carbon existing from the surface of the inorganic pigment particles to a depth of 7 nm is preferably 80 atom% or more.

  The amount of carbon existing from the depth of 7 nm to the depth of 17 nm from the surface of the inorganic pigment particles is preferably 85 atom% or more. When the carbon content is within the above range, the inside of the inorganic pigment particles is hardly fluorinated, so that the inorganic pigment particles are hardly precipitated in the dispersion medium, and the dispersibility is good.

<Inorganic pigment particles and production method thereof>
The inorganic pigment particles according to the present invention can be formed by bringing a mixed gas containing fluorine and nitrogen into contact with particles serving as a substrate (fluorine gas treatment).

The fluorine gas concentration in the mixed gas is preferably 0.1 wt% or more, and more preferably 0.5 wt% or more. If the fluorine gas concentration in the mixed gas is too low, dispersibility is poor because almost no fluorine can be present on the surface of the inorganic pigment particles. However, by adjusting the fluorine gas concentration within the above range, A predetermined amount of fluorine can be present on the surface portion. The fluorine gas concentration is preferably 50 wt% or less, more preferably 30 wt% or less, and even more preferably 20 wt% or less. If the fluorine gas concentration is too high, dispersibility is poor because the surface portion of the inorganic pigment particles becomes hydrophobic due to excessive progress of fluorination. Moreover, fluorination inside the inorganic pigment particles proceeds. Further, even when a black carbon-based material is used as the base particle, it may be changed to white CF ₄ . In the present invention, since the progress of fluorination can be suppressed by setting the fluorine gas concentration within the above range, the dispersibility is improved. Further, fluorination can be suppressed mainly to the surface portion of the inorganic pigment particles, not to the entire inorganic pigment particles.

  The nitrogen gas concentration in the mixed gas is preferably 50 wt% or more, more preferably 70 wt% or more, and even more preferably 80 wt% or more. By setting the nitrogen gas concentration within the above range, the fluorine gas concentration in the mixed gas can be reduced to a predetermined concentration or less, so that the progress of fluorination can be suppressed.

  The total of the fluorine gas concentration and the nitrogen gas concentration in the mixed gas is 100 wt% or less, and the mixed gas may contain a gas of an element other than fluorine gas and nitrogen gas (oxygen gas or the like). Even when the mixed gas does not contain oxygen gas, the oxygen element is contained in the surface of the inorganic pigment particles after the fluorine treatment due to the oxygen element contained in the moisture or the like present in the substrate particles or on the surface of the substrate particles. Will exist.

  Moreover, it is preferable that a fluorine gas process is performed at 35 degreeC or more, More preferably, it is 50 degreeC or more, More preferably, it is 80 degreeC or more. If the treatment temperature is too low, the progress of the fluorine treatment becomes very slow, but this can be suppressed by setting the treatment temperature within the above range. Moreover, it is preferable that a fluorine gas process is performed at 300 degrees C or less, More preferably, it is 250 degrees C or less, More preferably, it is 200 degrees C or less. If the treatment temperature is too high, the fluorine gas treatment proceeds too much and the particles are fluorinated to the inside of the particles. However, by making the treatment temperature within the above range, the progress of fluorination can be suppressed.

  Furthermore, the treatment time is preferably 1 minute or longer, more preferably 5 minutes or longer, and even more preferably 30 minutes or longer. If the treatment time is too short, almost no fluorine can be present on the surface portion of the inorganic pigment particles, but if it is within the above range, a desired amount of fluorine can be present on the surface portion of the inorganic pigment particles. The treatment time is preferably 240 minutes or less, more preferably 180 minutes or less, and even more preferably 120 minutes or less. If the treatment time is too long, the fluorine treatment proceeds and the inorganic pigment particles are fluorinated to the inside, but by making it within the above range, the progress of the fluorine treatment can be suppressed, and the surface portion of the base particle is mainly made of fluorine. It can be processed.

  Further, when the substrate particles are treated with fluorine gas in the treatment layer, the pressure in the tank is preferably 1 kPa or more and 90 kPa or less, and more preferably 50 kPa or more and 90 kPa or less. By setting the pressure in the tank within the above range, leakage of corrosive fluorine gas from the treatment layer can be suppressed.

  The volume average particle diameter of the inorganic pigment particles is preferably, for example, from 100 nm to 3000 nm, and more preferably from 100 nm to 2000 nm. If the volume average particle diameter of the inorganic pigment particles is within the above range, it is desirable because the inorganic pigment particles are stably dispersed without settling. The volume average particle diameter of the inorganic pigment particles is determined by dispersing the inorganic pigment particles in pure water and using a dynamic light scattering particle size distribution measuring device (for example, “LB-500” manufactured by Horiba, Ltd.). It is calculated | required by measuring the volume average particle diameter of a pigment particle and a suspected thing.

  The inorganic pigment particles of the present invention can be stably dispersed in various liquids by having fluorine and oxygen present on the surface of the inorganic pigment particles. In dispersing, since the inorganic pigment particles are uniformly dispersed without requiring high dispersion energy, they can be usefully used for various applications. As a use, for example, it is suitable for various uses that require dispersion stability of pigment particles of printing ink, paint, and ink for ink jet printer.

  As the dispersion medium for the inorganic pigment particles, a nonpolar dispersion medium and a polar dispersion medium can be used. Examples of the nonpolar dispersion medium include hydrocarbon nonpolar dispersion media such as hexane, cyclohexane, and cyclopentane; aromatic nonpolar dispersion media such as benzene, toluene, o-xylene, m-xylene, and p-xylene; And silicone oil nonpolar dispersion media such as silicone oil and methylphenyl silicone oil. As polar dispersion media, aprotic polar dispersion media such as acetone, tetrahydrofuran, acetonitrile, N, N-dimethylformamide, dimethyl sulfoxide; water, methanol, ethanol, 1-propanol, 2-propanol, n-butanol, formic acid And other protic polar dispersion media.

  In addition, you may add a dispersing agent, dye, a viscosity modifier etc. to the dispersion liquid of an inorganic pigment particle | grain suitably.

  The dispersant that can be added to the dispersion medium is not particularly limited as long as it is a dispersant that can be used to assist the dispersion of the inorganic pigment particles in the dispersion medium. Anionic surfactant, cationic surfactant, amphoteric surfactant, nonionic surfactant, fluorosurfactant, norbitane fatty acid ester surfactant such as norbitane sesquiolate, block Examples thereof include dispersants such as mold polymers and graft polymers, and various coupling agents. These dispersants may be used alone or in combination of two or more.

  The dispersibility when the composition of the surface portion of the inorganic pigment particles was changed by changing the fluorine gas treatment conditions was examined.

Example 1
About 1 g of carbon black (“06-0026” manufactured by Stream Chemicals, Inc., primary particle average particle size 10 nm (nominal value)) is spread thinly on a nickel tray, and sealed in a cylindrical nickel container having a capacity of 3 L. did. The nickel container is formed so that it can be heated and sealed. The atmosphere in the nickel container is evacuated, the inside of the nickel container is heated to 100 ° C. in a vacuum state, and a mixed gas of fluorine and nitrogen (mixing ratio F ₂ : N ₂ = 1 vol%: 99 vol%) is flowed from the gas introduction pipe. The mixture was introduced at 80 ml at 0.5 ml / min, and the inside of the nickel container was filled with a mixed gas. This state was maintained for 1 hour, and the carbon black was treated with fluorine gas.
After 1 hour, the mixed gas was evacuated and purged with nitrogen gas. A nickel tray was taken out of the nickel container, and about 1 g of fluorine-treated carbon black was obtained. Then, the carbon amount, oxygen amount, fluorine amount, zeta potential, fluidity, oil absorption, dispersibility, and discoloration of the carbon black subjected to fluorine treatment were measured. The results are shown in Table 1.
(Examples 2 to 8, Comparative Examples 1 and 2)
The same procedure as in Example 1 was performed except that the fluorine treatment conditions were changed to those shown in Table 1. The results are shown in Table 1. In Comparative Example 1, no fluorine treatment was performed.
In Table 1, the amount of each element at a predetermined thickness from the surface of the fluorine-treated carbon black indicates the amount of each element after etching the carbon black. The etching process was performed under the condition of a voltage of 500V.

The measurement method will be described below.
<Quantification of elements>
The amount of fluorine was measured by the following method. First, set the sample particle powder on the measurement substrate with double-sided tape, specify the detected atoms with ESCAWide Scan using an X-ray photoelectron spectrometer ("S-Probe" manufactured by Surface Science Instruments), and then for each atom The measurement was performed with a higher degree of quantification by performing a narrow scan, and the fluorine content of the sample particle surface layer was measured.
Next, after performing an etching treatment by irradiating with 500 V argon ions for a predetermined time, ESCA WideScan and Narrow Scan were performed, and the amount of fluorine at each depth was measured from the surface of the inorganic pigment particles by a method of measuring the amount of fluorine.
The amount of carbon and the amount of oxygen were also quantified by the same method as the amount of fluorine.

<Evaluation of dispersibility>
1 g of sample particles was put in 100 cc of pure water. This was subjected to ultrasonic dispersion for 10 minutes using an ultrasonic bath to prepare a dispersibility test solution. And the dispersion state of the sample particle | grains in a pure water was confirmed visually, and sample particle | grains were evaluated based on the following item.
○: Dispersibility of the sample particles is good and the dispersion state is maintained for 1 hour or more.
Δ: Dispersibility of the sample particles is improved, and the sample particles are dispersed in pure water but cannot be maintained for more than 1 hour.
X: The sample does not disperse in pure water.

<Measurement of volume average particle size>
The volume average particle size of the fluorine-treated carbon black was measured by placing sample particles in pure water, performing ultrasonic cleaning for 10 minutes, setting the uniformly dispersed dispersion in a measurement cell, and using a dynamic light scattering method. Using a particle size distribution measuring device (Zetasizer Nano ZS90 manufactured by Spectris Co., Ltd.), the volume average particle diameter of sample particles and suspected substances was measured. FIG. 2 shows the result.

<Zeta potential>
The zeta potential of the fluorine-treated carbon black was measured using a zeta potential measuring device (Spectasizer Nano ZS90 manufactured by Spectris).

<Viscosity>
The viscosity of the fluorine-treated carbon black (inorganic pigment particles) was measured according to JIS K5101.
Aggregated inorganic pigment particles have high resistance due to high resistance, but dispersed inorganic pigment particles have low resistance because of low resistance. Thus, dispersibility can also be evaluated by viscosity.

<Oil absorption amount>
The oil absorption of the fluorine-treated carbon black was measured according to JIS K5101.
Aggregated inorganic pigment particles have a small surface area and therefore a small amount of oil absorption. However, dispersed inorganic pigment particles have a large amount of oil absorption because each particle absorbs oil from the entire surface. Thus, dispersibility can also be evaluated by the amount of oil absorption.

  In Examples 1 to 8, a predetermined amount of fluorine and oxygen are present on the surface of the carbon black. In these examples, since the surface portion of the carbon black could be uniformly charged and the surface portion of the carbon black could be made hydrophilic, the dispersibility in the solvent was good. In particular, in Example 5, the inorganic pigment particles were dispersed even after a long period of time of one week or longer. In addition, although the dispersibility of Example 8 is Δ, since there is no problem in dispersibility when used as inorganic pigment particles, it can be evaluated that the dispersibility is good.

  On the other hand, in Comparative Example 1 in which the fluorine treatment was not performed, fluorine was not present on the surface portion of the inorganic pigment particles. Therefore, the surface portion of the inorganic pigment particles was not charged and the dispersibility was poor. Moreover, in Comparative Example 2, although fluorination was performed, fluorination progressed too much, so that it was fluorinated to the inside of the particles, the particle density increased, and it was considered that the particles were precipitated in the dispersion medium. In addition, although black carbon black was used, fluorination progressed too much, so that the color changed to white fluorocarbon.

  As mentioned above, although embodiment of this invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is indicated not by the above description but by the scope of claims for patent, and all modifications within the meaning and scope equivalent to the scope of claims for patent are included.

Claims (10)

Fluorine, carbon and oxygen exist from the surface of the inorganic pigment particles to a depth of 7 nm,
Inorganic pigment particles, wherein the amount of fluorine existing from the surface of the inorganic pigment particles to a depth of 7 nm is less than 16 atom%, the carbon amount is 80 atom% or more, and the oxygen amount is 0.1 atom% or more. .   2. The inorganic pigment particle according to claim 1, wherein an amount of fluorine existing at a depth of 7 nm from the surface of the inorganic pigment particle is 7.0 atom% or less and an oxygen amount is 0.1 atom% or more. The inorganic pigment particles are formed by subjecting substrate particles to fluorine treatment,
The inorganic pigment particles according to claim 1 or 2, wherein a main component of the substrate particles is a carbon material.   The inorganic pigment particle according to claim 3, wherein the carbon material is carbon black.   The inorganic pigment particles according to any one of claims 1 to 4, wherein an amount of fluorine from the surface of the inorganic pigment particles to a depth of 17 nm to 27 nm is 5 atom% or less. A step of bringing a mixed gas containing fluorine and nitrogen into contact with the substrate particles,
The mixed gas has a fluorine gas concentration of 0.1 wt% or more and 50 wt% or less, a nitrogen gas concentration of 50 wt% or more,
The said process is performed at 35 degreeC or more and 300 degrees C or less, The manufacturing method of the inorganic pigment particle characterized by the above-mentioned.   The said process is performed at 80 degreeC or more and 150 degrees C or less, The manufacturing method of the inorganic pigment particle | grains of Claim 6 characterized by the above-mentioned.   The method for producing inorganic pigment particles according to claim 6, wherein the mixed gas has a fluorine gas concentration of 30 wt% or less.   The method for producing inorganic pigment particles according to claim 6, wherein the mixed gas has a nitrogen gas concentration of 70 wt% or more.   The method for producing inorganic pigment particles according to any one of claims 6 to 9, wherein the substrate particles are carbon black.