JPS61201610A - Black powder and its preparation - Google Patents

Abstract

PURPOSE:To obtain easily preparable black powder having high degree of blackness, superior dispersibility, allowing titanium hydroxide or TiO2 powder having deposited V compd. thereon to react with gaseous NH3 by heating. CONSTITUTION:A V compd. (e.g. ammonium vanadate) is deposited on the powder of titanium hydroxide or TiO2. The powder is then allowed to react with gaseous NH3 at 550-900 deg.C to obtain aimed black pigment powder, which consists of particles of oxynitride of Ti and V contg. 0.1-7wt% V, 5-35wt% O, and 2-20wt% N. If a compound body of tetragonal and cubic crystal systems of oxynitride of Ti and V contg. larger proportion of the cubic crystal is used, the degree of blackness may be improved further.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a black pigment powder and a method for producing the same. More specifically, the present invention relates to a black powder made of an oxynitride of titanium and vanadium that has good dispersibility and is easy to produce, and a method for producing the same.

Carbon black powder and magnetite powder are well known as conventional black pigments. carbon blur 2
When used as a filler, powder may not be compatible with some base materials, is difficult to disperse, is bulky, and has a much larger specific surface area than other pigments, resulting in uneven dispersion when mixed with other pigments. There are disadvantages such as being prone to

Magnetite powder has agglomeration due to magnetism and has poor dispersibility. There are also problems with heat resistance, such as oxidation into brown magnetite (γ-Fe 203 ) at around 150° C. in the atmosphere. A low-order titanium oxide Tis--f (2≦n≦4) is known as a black powder that overcomes these drawbacks. This can be obtained by reducing titanium dioxide powder with Ti powder or hydrogen gas at a temperature of 1000° C. or higher. However, these methods cause significant particle growth and sintering.

There was a drawback that the particles became coarse particles (1.0 gm or more) which were unsuitable for use as pigments.

We first added 500 ml of titanium dioxide powder and ammonia gas.
It has been found that when the reaction is carried out at a temperature of ~950°C, a black-toned fine titanium nitride powder that maintains the original particle size can be obtained. According to this manufacturing method, it is possible to avoid coarsening of a single particle due to sintering, but when it is carried out on an industrial scale, it is necessary to increase the reaction efficiency between titanium oxide powder and ammonia gas.

1.A1 The present inventor attempted to improve the method for producing black powder using titanium oxide, and first found that when titanium hydroxide powder with a large specific surface area was used as a starting material, the reactivity with ammonia gas increased. . Furthermore, less NH in a shorter time
We investigated starting materials that turn black when used in amounts of 3 and investigated the effects of combining titanium hydroxide and titanium oxide with metal compounds. The metal salts to be added include V, Cr, and Mn.

Select ammonium salts, acetates, nitrates, oxalates, etc. of Fe, Cu, Mo, W, etc., and avoid chlorides that may cause problems during the reaction.
Sulfates were avoided. As a result, it was found that by attaching a vanadium compound to powders of titanium hydroxide and titanium oxide and heating and reacting them with ammonia gas, fine black particles with a high degree of blackness could be obtained in a short time. Furthermore, the oxynitrides obtained by the above manufacturing method include Ti, V, O, N
The present invention is based on the above findings, and the present invention is based on the above findings. For example, it is made of oxynitride particles of titanium and vanadium, with a vanadium content of 0.1 or more and less than 7.0% by weight, an oxygen content of 5 or more and less than 35% by weight, and a nitrogen content of 2
There is provided a black powder characterized in that the content is less than 20% by weight, and the black powder is further produced by attaching a vanadium compound to titanium hydroxide or titanium oxide powder and then reacting the vanadium compound with ammonia gas by heating. The vanadium compounds used in the present invention include ammonium vanadate (NO4vo3), /<+sodium zinate (Na
VO3) is common, but ammonium salts that do not cause problems such as grain growth and sintering during reduction and do not have a negative effect on the product are preferred. A method for attaching vanadium compounds to the surface of the present titanium titanium oxide and titanium oxide powders. This can be easily carried out by the immersion-adsorption method and the kneading method.

Titanium hydroxide has a high ability to adsorb metal ions, so 0.1 to 15 g of ammonium vanadate (NH4VO3) can be added to titanium hydroxide.
Titanium hydroxide particles were suspended in an aqueous solution at a slurry concentration of 50 to 300 g/l to adsorb vanadate ions onto the titanium hydroxide. After that, solid-liquid separation is performed immediately, and the precipitate is dried and crushed before use.
Since titanium oxide has a small adsorption capacity, it may be used by sufficiently kneading an aqueous solution containing ammonium vanadate and titanium oxide powder, drying, and pulverizing.

The black powder of the present invention has a composition of vanadium (1.1 to 7.0% by weight, 5 to 35% by weight of oxygen, and 2 to 20% by weight of nitrogen.
If the amount is less than %, the powder will have a bluish-gray color and the blackening will be insufficient. and less than 5% by weight of oxygen and 20% by weight of nitrogen.
If the reduction and nitrogenation is exceeded, the powder becomes brownish brown and does not become a black powder. Addition of a small amount of zero-order vanadium produces superior blackness compared to the case without addition, and a specific surface area that suppresses the growth of sintered grains. It becomes a large fine powder. If the amount of vanadium added is less than 0.1% by weight, the degree of blackness will be insufficient even if the content of oxygen and nitrogen is within the above range.

Furthermore, if the vanadium content exceeds 7.0% by weight, the blackening will not proceed regardless of the amount of oxygen and nitrogen, but rather the color will become brownish.

Next, in the manufacturing method of the present invention, a predetermined amount of a vanadium compound is attached to powder of titanium hydroxide or titanium oxide, and then this is heated and reacted with ammonia gas. The temperature of the heating reaction with ammonia is in the range of 550 to 800°C.

If the temperature is less than 550°C, the powder tends to lack blackness even if heated for a long time, and if it exceeds 900°C, it becomes brown and difficult to blacken, and some sintering occurs, causing the particles to become coarse and fine. It becomes difficult to obtain a suitable powder. The flow rate of ammonia gas may be at least 0.5 cm/see in terms of linear velocity within the furnace.

The blackness of the black powder of titanium and vanadium oxynitride differs depending on its crystal form. That is, if the intensity ratio (tetragonal/cubic system) determined by X-ray structural analysis is less than 872, that is, if the ratio of the cubic system is high, a black powder will be obtained. However, even if only the cubic crystal system is used, the oxygen and nitrogen content is 20% nitrogen.
If the weight percent is exceeded and the oxygen content is less than 5 weight percent, the powder will turn brown.The present invention can be achieved by adjusting the amount of the above components within a predetermined range, attaching a vanadium compound, and heating and reacting it with ammonia gas at a predetermined temperature. It is possible to obtain a powder with a higher degree of blackness, which has more cubic crystal system compared to the conventional powder.

According to the manufacturing method of the present invention, the degree of blackness is higher than that of titanium oxynitride that does not contain a vanadium compound.

Moreover, fine particles with a large specific surface area and with suppressed sintering during reaction can be obtained in a short time. This is because by attaching a vanadium compound to titanium hydroxide or titanium oxide, the reactivity increases and the raw material becomes black powder in a short time without sintering. This is thought to be due to the increase in blackness due to a combined effect.

! - and 1 Example 1 300 g of titanium hydroxide powder (Tohoku Chemical Industry Co., Ltd.) with a specific surface area of 210 m2/H was mixed with ammonium metavanadate (NH4
VO3) suspended in 2 fL of an aqueous solution with a concentration of 5 g/l,
Stir thoroughly. This is divided into ovens, dried, and crushed into 5 powders, 30
g into the port and ammonia at a linear velocity of 3 cm inside the furnace.
/see, and reacted for 1 hour at a furnace temperature of 750° C. The recovered powder weighed 22 g and had a blue-black color. Blackness is L value (color computer SM3 manufactured by Suga Test Instruments)
Color measurement) 10.4, specific surface 77433rn2/g, electrical resistance 9.8X10°Ω-cm (10Kg/Cl12
The content of each of V, O, and N was 1.8.27.8% by weight. The tetragonal/cubic intensity ratio by X-ray diffraction was 7/3.

Example 2 The reaction was carried out under the same conditions except that the reaction time was 2 hours. The results are shown in Table 1.

Examples 3-6 Using 200 g of the same titanium hydroxide powder as in Example 1, NH
4VO! The concentration is 0.3.10g/! Disperse the changed seta in 2 batches of aqueous solution, separate it from the oven, dry it, crush it, and then add it to the port.
Take 5g of ammonia gas at a linear velocity of 3cm/sec in the furnace.
Table 1 shows the results of the recovered powder, which was reacted by changing the heating temperature and time.

Examples 7-8 Titanium hydroxide powder or titanium dioxide powder used in Example 1 (Tohoku Chemical System, specific surface area 9 m2/g) (1) 1
00gt-NH4V03 concentration log/4117) Aqueous solution 19. and dried with a spray dryer. 25 g of this powder was placed in a boat, ammonia gas was passed through the furnace at a linear velocity of 3 cm/sea, and the reaction was carried out at a furnace temperature of 750°C. The results are shown in Table 1.

Comparative Examples 1 to 2 The titanium hydroxide powder used in Example 1 and the titanium dioxide powder used in Example 8 were charged into a boat, and ammonia gas was passed through the furnace at a linear velocity of 3 cm/sec to bring the furnace temperature to 75.
The reaction was carried out at 0°C. The results are shown in Table 1.

Comparative Example 3 300g of titanium hydroxide powder used in Example 1 was added to N)+4
VO3(7) concentration 0.3g/2(7) aqueous solution 29.
The mixture was suspended in the liquid, thoroughly stirred, separated in a furnace, dried, and pulverized.

25g of powder was charged into a boat, ammonia gas was flowed at a linear velocity of 3cm/sec in the furnace, and the reaction was carried out for 1 hour at a temperature of 750°C in the furnace.20g of the recovered powder had a blue-black color. Blackness value 15.7, specific surface Jd 19m2
/g, and the electrical resistance was 3 x 102 Ωecm.

Also.

The contents of (1), 0, and N were 0.08.34.3% by weight, respectively. Moreover, the intensity ratio of tetragonal system/cubic system by X-ray diffraction was 8/2.

Comparative Example 4 Titanium hydroxide powder 100gt-N)I used in Example 1
Suspended in an aqueous solution of 4VO3 with a concentration of 14 g/l,
Stir thoroughly. This was dried using a spray dryer. 25 g of powder was charged into the port and the reaction was carried out under the same conditions as in Comparative Example 3. The recovered powder weighed 18.5 g and exhibited a brown-black color, the L value of blackness was 14.3, and the specific surface area was 28 m2.
/g, electrical resistance? , 2XlO'Ω*cm. Also, the content of each of V, O, and N is 7.5.18.13
The tetragonal/cubic intensity ratio was 515 by X-ray diffraction.

Claims (1)

[Claims] 1. Consists of oxynitride particles of titanium and vanadium, with a vanadium content of 0.1 or more and less than 7.0% by weight, an oxygen content of 5 or more and less than 35% by weight, and a nitrogen content of 2 A black powder characterized by having a content of at least 20% by weight. 2. The black powder according to claim 1, characterized in that the oxynitride of titanium and vanadium is a composite of a tetragonal system and a cubic system or only a cubic system. 3. A method for producing black powder, which comprises adhering a vanadium compound to titanium hydroxide or titanium oxide powder, and then reacting the vanadium compound with ammonia gas by heating. 4. The manufacturing method according to claim 3, characterized in that the reaction with ammonia gas is carried out at a temperature range of 550 to 900°C.