TWI266747B - Silicon-titanium mixed oxide powder produced by flame hydrolysis - Google Patents

Abstract

Silicon-titanium mixed oxide powder produced by flame hydrolysis, which consists of aggregates of primary particles, with a BET surface area of 90 ± 15 m<2>/g, a titanium dioxide proportion of 50 ± 8 wt.% and an anatase/rutile ratio of 60:40 to 70:30. It is produced in that a mixture of silicon halide, titanium halide, hydrogen and primary air is ignited in a burner and the flame is burned into a reaction chamber closed off from the surrounding air, and secondary air and a gas, which increases the temperature in the reaction chamber by combustion and/or which slows down the cooling in the reaction chamber because of low heat transfer, are additionally introduced into the reaction chamber. It can be used in toner compositions.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bismuth-titanium mixed oxide powder obtained by a flame hydrolysis method, and its manufacture and use. [Prior Art] US 6 6 7 7095 discloses a binary metal mixed oxide powder having a composition of ruthenium dioxide, aluminum oxide and titanium oxide; and it is preferably in a hydrophobized form. These powders are said to have good dispersibility, good flow properties and high static charge. • Surface-modified metal mixed oxide powders are known from EP-A 722 992. For example, bismuth-titanium mixed oxide powders, and their use as charge stabilizers and anti-caking agents in toner powders. However, it has been found that a suitable toner composition is generally not obtained by using the hydrophobized powder disclosed in EP-A 722 992. φ In U S 6 1 3 0 0 2 0, a composite having a composition of SixTiyO(4x + yz)/2 in the toner composition is requested. In the formula, z is the valence of titanium and x/y is from 1 to 25. In the range of the quotient x/y, all the compositions are equally applicable to the toner composition. u s 6 1 3 0 0 2 0 does not reveal the modification of these oxides, and its BET surface area is composed. The cerium-titanium mixed oxide powder obtained by flame hydrolysis is known. In this process, a mixture of tetrachloride and titanium tetrachloride is usually hydrolyzed in a flame. The flame can be produced, for example, by the reaction of hydrogen with atmospheric oxygen. As a result, the moisture required for the hydrolysis of the chloride is formed. As for the reaction product, 5-(2) 12616747 矽-titanium mixed oxide powder and hydrochloric acid were obtained, some of which still adhered to the powder, but not in the method described in the prior art, which only formed a limited ratio of TiO 2 /SiO 2 . powder. Thus, in DE-A-293 1 8 1 0, a niobium-titanium mixed oxide powder containing 0.1 to 9.9% by weight of titanium dioxide is claimed. It is prepared by evaporating hafnium tetrachloride, diluting it with preheated air, and mixing hydrogen and titanium tetrachloride in a mixing chamber and burning the mixture in the reaction chamber. In ED-A-423 5996, a cerium-titanium mixed oxide powder containing 70 to 99% by weight of titanium dioxide is requested. It is produced by evaporating ruthenium tetrachloride and transferring it to a mixing chamber using an inert gas where it is mixed with hydrogen, oxygen, titanium and titanium tetrachloride, and the mixture is burned in a reaction chamber. The mixed oxide powder or the hydrophobic mixed oxide powder described so far is not unstable when used in the toner composition, or has only limited stability. Disclosure of the Invention An object of the present invention is therefore to provide a cerium-titanium mixed oxide powder which can be used particularly advantageously in a toner composition. It should exhibit advantages over prior art in dispersibility, flow and static charge. The invention also provides a method of making such bismuth-titanium mixed oxide powders.

The present invention also provides a cerium-titanium mixed oxide powder obtained by flame hydrolysis, which is composed of aggregates of primary particles, and is characterized in that its BET (3) 12616747 surface area is 90 ± 15 m 2 /g, titanium dioxide. The ratio is 50 ± 8% by weight and the anatase / rutile ratio is 60: 40 to 70: 30. The term ''flame hydrolyzed hydrazine' refers to a process in which a vaporized metal precursor or a metalloid precursor is hydrolyzed in a flame. The flame is produced by the reaction of hydrogen, methane or a similar gas with air or oxygen. At least one of the reaction products is water which promotes hydrolysis of the metal precursor or metalloid precursor. As a result, the primary particles are formed in the initial phase, and the primary particles are aggregated together to form a polyφ aggregate during the reaction. In the mixed oxide powder of the present invention, crystalline titanium oxide is present, and the cerium oxide portion is amorphous under X-ray. The TEM photograph of the aggregate shows that there are partial or complete titanium dioxide shells and primary particles of a titanium dioxide core. In addition, there are also cerium oxide and titanium dioxide together, and have Ti-O-Si bonds. Primary Particles It has been shown that powders having such compositions, BET surface area and anatase/rutile ratio are ideally suited for use in toner compositions. In these applications, they exhibit good dispersibility. High fluidity and high static charge. In addition to SiO 2 and TiO 2 , the mixed oxide powder of the present invention may also contain a small amount of impurities or process-related impurities from the feed. In total, these impurities are less than 1% by weight, usually less 1% by weight. In particular, the mixed oxide powder of the present invention may also contain a chloride. The mixed oxide powder of the present invention has an intermediate enthalpy of from 1 to 14 nm of the original particle diameter and 5 to 40 nm. It is preferred that the original particle diameter number is 90% span. Such narrow original particle distribution can exhibit further advantages in toner application and catalytic applications. (4) (4): 1266747 In addition to the original particles Poly The size of the aggregate can also vary. In particular, the preferred mixed oxide powder of the present invention has: - an equivalent circle diameter (ECD) number less than 90 nm, and an aggregate of less than 7500 square nanometers. The area is based on the middle enthalpy, and • the circumference of the aggregate of less than 600 nm is the intermediate enthalpy. Furthermore, the tamped density of the mixed oxide powder of the present invention can be varied. It plays an important role in metering and processing. It is usually between 20 and 200 g/l. The mixed oxide powder of the invention preferably has a plug density of 40 to 80 g/l. The invention also provides for the manufacture of the invention. a method of titanium mixed oxide powder, wherein - the sand halide and the titanium halide are evaporated, - the carrier gas is used to transfer the vapor into a mixing chamber, - separately from this, the oxygen can be optionally concentrated and/or The preheated hydrogen and primary air are transferred into the mixing chamber, and then the mixture of the cerium halide, titanium halide, hydrogen and primary air is ignited in a burner and the flame is burned to a closed reaction chamber enclosed by ambient air. To - additionally, separately from each other, the auxiliary air, and - a gas or gas mixture - which can increase the temperature in the reaction chamber via combustion, and / or it can slow down the cooling in the reaction chamber due to low heat transfer, leading to the reaction chamber Preferably, it is introduced through a circular nozzle, - then solids are separated from the gaseous material, and - 8 - (5) 1266747 - the solid is then substantially treated by steam treatment at a temperature of 25 0 to 700 ° C. Halide-containing material to the greatest extent possible. In the process of the invention, it is necessary to introduce a gas or gas mixture which can increase the temperature in the reaction chamber via combustion and/or slow down the cooling in the reaction chamber due to low heat transfer. Below, a powder having the above-mentioned SiCh/TiCh content 値, BET surface area 値 and anatase/rutile content 可以 can be obtained. p. For the gas which increases the temperature in the reaction chamber by combustion, it is preferable to use hydrogen, methane, ethane, propane or natural gas. Ammonia, argon, carbon dioxide and/or carbon monoxide may be used for gases which slow down the cooling of the reaction chamber due to low heat transfer. Both types of gases are preferably used in an amount of from 0.0005 to 5 Nm3/h per gram per hour of SiCl4. It is particularly preferably in the range of 0.001 to 1 Nm 3 /h per gram per hour of SiCl 4 . As the cerium halide, barium tetrachloride, methyltrichloroanthracene and/or trichlorodecane are preferred, and barium tetrachloride is particularly preferred. As the titanium halide, titanium tetrachloride is preferably used. In addition, it has also proven to be advantageous to keep the evaporation temperatures of the titanium halide and the cerium halide as low as possible. In the case of titanium tetrachloride or titanium tetrachloride in the case of evaporation in the form of a mixture, it is advantageous to make the degree of evaporation not higher than 180 °C. In the case of ruthenium tetrachloride, it is advantageous to make the evaporation temperature not higher than 1 〇〇t. These practices increase the purity of the product. The ratio of the amount of hydrogen fed to the amount of hydrogen required for stoichiometry is called 7値. Similarly, the ratio of the oxygen feed to the stoichiometric amount of oxygen is called -9- (6) 747 is λ値. The term, stoichiometrically required herein, refers to the individual precise amounts of hydrogen and oxygen required for the hydrolysis of titanium-tellurium halides. Therefore, the following formula can be used: r = Η 2 feed amount (mole) / η 2 stoichiometric amount (mole) λ = 〇 2 feed amount (mole) / 〇 2 stoichiometric amount (mole) in the present invention In the method, if both 7 and λ are greater than 1.05, it proves to be advantageous. Further, in the method of the present invention, air is directly introduced into the reaction chamber (auxiliary air) in addition to the main air in the mixing chamber. It has been found that the mixed oxide powder of the present invention cannot be obtained without sending additional air to the mixing chamber. It is advantageous if the main air/auxiliary air ratio is between 10 and 0.5. In order to be able to accurately meter the amount of auxiliary air and gases introduced into the reaction chamber, the flame is burned to a reaction chamber that is isolated from the surrounding air. This allows for precise program control. The isolated state φ present in the reaction chamber is preferably between 5 and 80 mbar. The output velocity of the reaction mixture from the burner into the reaction chamber may preferably be from 10 to 80 m/sec. The invention also provides a method for producing a hydrophobized cerium-titanium mixed oxide powder, which comprises spraying a water-repellent agent or a water repellent mixture, optionally in the presence of water, to the cerium-titanium mixed oxidation obtained by the flame hydrolysis of the invention. The powder is then mixed for 15 to 30 minutes and then tempered at a temperature of 1 to 500 ° C for 1 to 6 hours. All of the water repellents listed in EP-A-7 2 2 9 2 2 can be used in this item-10-(7) 1266747, preferably hexamethyldioxane, trimethoxyoctyl Decane, dimethyl polyoxane and trimethoxypropyl decane. The present invention also provides a hydrophobized cerium-titanium mixed oxide powder obtained by this method. The hydrophobized cerium-titanium mixed oxide powder may have a BET surface area of 50 to 100 m 2 /g and a carbon content of 0.5 to 5% by weight depending on the reaction conditions. The present invention also provides the use of the cerium-titanium mixed oxide powder of the present invention and the hydrophobized cerium-titanium mixed oxide powder of the present invention, which is used as a toner mixture, as a UV blocker in a cosmetic preparation, as A catalyst or catalyst carrier, as a photocatalyst, as a reinforcing material in an anthrone rubber and rubber, as an anti-caking agent, as an anti-blocking agent in a film and Used as a thickener in coatings. [Embodiment] H Example Analysis = BET surface area was measured in accordance with DIN 66131. The contents of SiO 2 and TiO 2 were determined by X-ray fluorescence analysis and/or chemical analysis. The plug density is determined according to DIN ISO 78 7/XI K 5101/18 (end screened). The pH is determined by reference to DIN ISO 78 7/IX, ASTM D 1 280, JIS K 5101/24. The size of the original particles and aggregates was determined by image analysis - image analysis using a TEM instrument from Hitachi H7 5 00 and -11 - (8) 1266747 from SIS.

Megaview II CCD camera implementation. The image magnification used for the evaluation was 3 0000 : 1, and the pixel density was 3.2 nm. The number of particles evaluated is greater than 1 000. The preparation is carried out in accordance with ASTM 3 8 49-89. The lower limit of detection is 550 pixels. Example 4: Ammonium tetrachloride and tetrachlorochloride were vaporized together in an evaporator at 1,600 °C. The vaporized vapor is transferred to the mixing chamber by helium gas, and separately from this, hydrogen gas and main air are introduced into the mixing chamber. In a central tube, the reaction mixture is sent to a burner and ignited. Burn the flame into a water-cooled combustion tube. Further, separate air and hydrogen, or a mixture of carbon dioxide or hydrogen/carbon dioxide, are introduced into the reaction chamber separately from each other. The resulting powder was separated in a downstream filter and then treated countercurrently with steam. Table 1 shows the feed and its amount as well as the combustion parameters. Table 2 shows the physicochemical data of the powder. Example 5: Hydrophobization of the mixed oxide powder obtained in Example 2. The mixed oxide powder obtained in Example 2 was sprayed at a ratio of 10 g of dimethyl polyoxyalkylene / ruthenium mixed oxide powder, and then mixed for 20 minutes. The tempering treatment was then carried out at a temperature of 250 ° C for 2 hours. The product had a beta surface area of 74 square meters per gram and a carbon content of 2.5%. Example 6: The same procedure as in Example 5 was carried out except that the mixed oxide powder (91% by weight of SiO 2 and 9 weights) obtained according to -12-(9) 1266747 DE-A-29 3 1 8 1 0 was used. /〇Ti02). Its BET surface area and carbon content were close to those obtained in Example 5. Example 7: The same procedure as in Example 5 was carried out. However, the mixed oxide powder (25% by weight of SiO 2 and 75% by weight of TiO 2 ) prepared according to DE-A 423 6996 was used. Its BET surface area and carbon content were close to those obtained in Example 5. Example 8.1: A mixed oxide comprising Example 5 or Example 7 obtained from Example 5 of the present invention was fabricated according to US Pat. No. 6, 1 3 0 0 0 0 0, column 6, line 61. A toner composition of a powder. Table 3 shows the advantages of using the toner composition of the hydrophobized mixed oxide powder obtained in Example 5 of the present invention.

-13- (10)1266747

3⁄4德·錾恶3⁄4绷: 嗽 Reaction chamber (NK ε 00 d 1 (Ν Ο ON Ο C〇2 ε 1 &lt;η Ο (Ν Ο 1 auxiliary air ms burner VO r—Η 1.61 1.69 1.69 Η rH 1.48 1.99 1.99 g Um CD &gt; m/s 26.9 27.5 36.9 36.9 Main air S 9.70 9.60 13.30 13.30 rs ffi m B 2.50 2.50 3.30 3.30 TiCl4 kg/h 3.00 2.70 3.00 3.00 SiCl4 kg/h 3.60 4.00 3.60 3.60 Example (Ν Cn inch-14- 1266747

韬锣腾和刮/伥鑫松Λ3&gt;秘如魃尨-/a :(Ν撇中周长奈米1 438 445 藤群物η intermediate area square nanometer 1 4183 4225 1 intermediate ECD nano 1 73.0 74.2 1 original Particle η 90% span nanometer 1 8.5-36.4 6.4-41.3 1 intermediate diameter nanometer ^- VJT. 1 16.1 00 yn τ-*Η Repeated enthalpy density gram / liter 00 ρ Η (&amp;) m vo cn 3.64 3.75 ON m anatase / rutile 65/35 66/34 64/36 61/39 Ti02 wt% 48.6 44.8 51.1 49.5 Si02 wt% 51.4 55.2 49.9 50.5 BET m2 / g ON (NO 100 00 Example rH (N m inch 恻窸伥=-(§): 嫠镒φ«% inch (1: touch} paste) -15- (12) β 1266747 Table 3: Properties of the toner mixture Example # Si02/Ti02 Charge Powder with property blending dispersibility 5 50/50 + + 6 91/9 + 7 25/75 〇+ 〇

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Claims (1)

(1) 1266747 &amp; September/3, revision (stupid) original ten, application for patent scope Annex 2: Patent application No. 94 1 1 5648 Patent application scope Replacement of the Republic of China, July 13, 1995 Revision 1· A bismuth-titanium mixed oxide powder prepared by a flame hydrolysis method is composed of aggregates of primary particles, characterized in that _ has a BET surface area of 90±15 m 2 /g, and a ratio of titanium dioxide is 50. ± 8 wt%, - anatase / rutile ratio of 60: 40 to 70: 30. 2) a cerium-titanium mixed oxide powder obtained by a flame hydrolysis method according to claim 1, wherein the number-based median value of the primary particle diameter is 14 to 18 nm and The base of the original particle diameter has a 90% span of 5 to 40 nm. 3. The cerium-titanium mixed oxide powder obtained by the flame hydrolysis method according to claim 1 or 2 of the patent application, wherein - the equivalent circle diameter (ECD) of the aggregate has a number intermediate 値 less than 95 奈m, - the median enthalpy of the area of the aggregate is less than 7,500 square nanometers, and - the intermediate number of the perimeter of the aggregate is less than 600 nanometers. 4. A cerium-titanium mixed oxide powder obtained by a flame hydrolysis method according to claim 1 or 2, wherein the tamPed density is 40 to 80 g/liter. A method for producing a niobium-titanium (2) 1266747 mixed oxide powder according to any one of claims 1 to 4, characterized in that - a halo halide and a titanium halide are evaporated, and a carrier gas is used. Transferring the vapor to a mixing chamber, - separately from which hydrogen and primary air, optionally enriched and/or preheated with oxygen, are transferred to the mixing chamber, and then igniting the hydrazine in the burner a mixture of titanium, a halide, a mixture of hydrogen and primary air and burning the flame into a reaction chamber enclosed by ambient air, and - additionally, separately from each other, the auxiliary air, and - a gas or gas mixture - Increasing the temperature in the reaction chamber, and/or reducing the cooling effect in the reaction chamber due to low heat transfer, leading to the reaction chamber, preferably through the annular nozzle, and then separating the solid from the gaseous material, and The solid is substantially removed by steam at a temperature of from 250 to 700 ° C to substantially remove the halide-containing material to the greatest extent possible. 6. The method of claim 5, wherein the gas that increases the temperature in the reaction chamber via combustion is hydrogen, methane, ethane, propane or natural gas. 7. The method of claim 5, wherein the gas which slows down the cooling in the reaction chamber due to low heat transfer is helium, argon, carbon dioxide and/or carbon monoxide. 8. The method according to claim 6 or 7, wherein the gas is used in an amount of 0.0005 to 5 Nm 3 /h per gram per hour of SiCl 4 . (3) • 1286747 9. According to the method of claim 5, wherein both r値 and λ 値 are greater than 1.05. 10. A method for producing a hydrophobized tantalum-titanium mixed oxide powder, characterized in that a water-repellent or water-repellent mixture is used, optionally in the presence of water, by spraying a flame hydrolysis method according to items 1 to 4 of the patent application. The ruthenium-titanium mixed oxide powder is prepared, followed by mixing for 15 to 30 minutes, and then tempering at a temperature of 100 to 500 ° C for 1 to 6 hours. The method according to the first aspect of the invention, wherein the water repellent is hexamethyldioxane, trimethoxyoctyldecane, dimethylpolyoxane or trimethoxypropylnonane. The use of the cerium-titanium mixed oxide powder obtained by the flame 'hydrolysis method according to any one of claims 1 to 4, which is used for a toner mixture, or in a cosmetic preparation Used as a UV blocker, either as a catalyst or catalyst carrier, or as a photocatalyst, or as a reinforcing buffer in anthrone rubber and rubber, or as an anti-caking agent W 'or The film acts as an anti-blocking agent or as a thickener in the coating.