JP5205638B2 - Method for producing alkali titanate - Google Patents

Description

The present invention relates to a method for producing an alkaline titanate.

  Alkali titanate is a material useful as a friction material for friction sliding members such as brake linings, disk pads, and clutch fading that constitute braking devices in automobiles, railway vehicles, aircraft, industrial machinery, and the like. Conventionally, as such a friction material, a friction material in which asbestos (asbestos) is dispersed in an organic or inorganic binder and formed by binding has been used. However, asbestos (asbestos) has insufficient friction and wear characteristics such as heat resistance, and has environmental health problems such as carcinogenicity, so there has been a strong demand for the development of alternatives in recent years. This is an urgent issue.

In response to such a demand, a friction material using an alkali titanate such as fibrous potassium titanate as a base fiber or a friction modifier has been proposed. In particular, potassium titanate fibers do not have carcinogenic properties such as asbestos, have excellent heat resistance, and have excellent characteristics that are effective in preventing fade phenomenon and improving the thermal stability of friction characteristics. In particular, among the potassium titanates represented by the general formula K ₂ O · nTiO ₂ (n is an integer of 1 to 12), the potassium 6 titanate fiber or the 8 potassium titanate fiber in which n is 6 or 8 has a tunnel structure. The friction material containing the above crystal structure has particularly excellent heat resistance and the like.

  However, many conventional potassium titanate fibers have an average fiber diameter of 0.1 to 0.5 μm and an average fiber length of 10 to 20 μm, and are within the range recommended by the World Health Organization (WHO) (inhalability) WHO fiber used as a fiber: other than a fibrous compound having an average minor axis of 3 μm or less, an average fiber length of 5 μm or more, and an aspect ratio of 3 or more.

  In addition, the conventional method for producing alkali titanate fibers or alkali titanate whiskers is complicated. For example, in the case of potassium titanate, a titanium compound such as titanium oxide and a potassium compound such as potassium carbonate are mixed and subjected to a firing reaction, and then water is added. It is manufactured by immersing the fiber in a fiber and neutralizing it with an acid to adjust the potassium component, followed by drying. In particular, potassium 6 titanate and potassium 8 titanate, which are excellent in heat resistance, have a tunnel structure, so that it is difficult to grow crystals in a whisker shape or a fiber shape. First, potassium dititanate or tetratitanate having a layered crystal structure. It is necessary to synthesize potassium fibers and then adjust the pH, and then fire again to convert them into tunnel-structure crystals, and the obtained fibrous material needs to undergo a special process such as defibration classification. For this reason, there existed a problem that a manufacturing cost will become expensive material. Furthermore, the potassium titanate fibers that have been industrialized have low bulk specific gravity, poor fluidity, and have problems such as insufficient supply in the production process, and obstruction by adhering to the walls of the supply path. . In addition, when the friction material is manufactured, it is difficult to uniformly mix it with the raw materials, and it is difficult to obtain a uniform friction material, and problems remain in terms of quality control.

  In order to solve these conventional problems, a friction material containing a layered / plate-like alkali titanate as a friction adjusting material instead of a fibrous material is disclosed (for example, see Patent Document 1). This friction modifier is a layered / plate-like potassium titanate having a major axis of 10 to 500 μm and a minor axis (thickness) of 50 to 1000 nm, and has no fiber shape, so the fluidity is inferior and the supply path is limited in the production process. There is little risk of obstruction, and in addition, there will be no deterioration of the working environment due to inhalation. However, in this case, the manufacturing process for manufacturing the alkali titanate is still complicated, and the manufacturing cost is high and the economic merit cannot be enjoyed at present. Similarly, there is disclosed a friction agent containing potassium titanate as a base fiber having a columnar shape or a plate shape having a cross-sectional diameter of 5 μm or more and a length of 50 μm or more (for example, Patent Document 2). However, even in this case, the same problem as described above cannot be solved.

  Moreover, in order to reduce manufacturing cost, the method of manufacturing an alkali titanate from the cheap ilmenite which contains a comparatively large amount of impurities as a titanium source is disclosed (for example, refer patent document 3). In this method, grinding treatment using a vibration mill is performed, and thereafter, baking is performed at a predetermined temperature to synthesize lithium potassium titanate and the like. However, in this production method, since ilmenite or the like containing a relatively large amount of impurities such as iron is used as a raw material, the alkali titanate produced by the production method contains a large amount of impurities, and treatment for removing this is necessary. In addition, it is difficult to control the composition of the alkali titanate to be produced by this production method. In particular, in order to obtain an alkali 6 titanate, once the 2 or 4 alkali titanate is produced, it is washed with water or pickled, It is necessary to go through a process such as firing at a predetermined temperature, which causes a problem that the manufacturing process becomes complicated.

JP 2000-265157 A JP-A-1-294553 JP 2003-335519 A

In view of the above-mentioned problems, the object of the present invention is high in thermal stability and is excellent as a base fiber for a friction material and a friction modifier, and has a simple shape such as a rod shape and a column shape with few fiber shapes. The object is to provide an inexpensive method for producing an alkali titanate. Another object of the present invention is to provide a method for producing an alkali titanate that can uniformly mix titanium oxide and an alkali raw material, provides an alkali titanate compound having a desired composition with good reactivity and high crystallinity and purity. There is.

  In such a situation, the present inventors have intensively studied, and as a result, by adopting a novel production method different from the conventional production method of alkali titanate, mainly rod-like, columnar, cylindrical, strip-like or It has a plate-like shape and can easily obtain an alkali titanate compound having a desired composition with high crystallinity and purity, and exhibits excellent heat resistance when this alkali titanate is used as a friction modifier. As a result, the present invention has been completed.

That is, in the present invention, an aggregate or granulated titanium compound and an alkali metal compound having an average particle diameter of 0.1 to 10 mm are pulverized and mixed by a vibrating rod mill, and the mixture obtained by the mixing is subjected to a firing reaction to thereby obtain titanic acid. A production method for producing an alkali , wherein the titanium compound is titanium oxide . Since the present invention uses agglomerates or granulated materials as raw materials, it can be uniformly mixed during pulverization and mixing, and in particular, by mixing and pulverizing with a vibrating rod mill, uniform mixing with less sticking of pulverized material to the inside of the mill can be achieved. it can. In addition, it is possible to suppress sticking by mixing with an additive for preventing sticking or agglomeration to achieve more uniform mixing.
As additives, alcohols and the like are preferably added. Moreover, you may include a titanium metal powder or a titanium hydride powder in a mixture. In the present invention, it is preferable to use an aggregate or granulated body of titanium oxide as the titanate compound, and it is preferable to use an alkali metal carbonate and hydroxide as the alkali metal compound. By using such a production method of the present invention, alkali 4 titanate or / and alkali 6 titanate can be produced easily and inexpensively. The alkali metal compound is preferably produced using a compound comprising at least one selected from potassium, sodium and lithium as a raw material. In particular, when potassium titanate is produced, potassium titanate having a desired composition can be produced by setting the firing temperature range to 800 to 1300 ° C. In particular, it is possible to produce potassium titanate having a large (long) average minor axis and average length (average major axis) by adjusting the rate of temperature rise during firing and increasing the firing temperature. That is, when the temperature rising rate is 0.5 ° C. to 2 ° C./min and the firing temperature is 1000 ° C. to 1300 ° C., the average minor axis is 3 μm or more and 10 μm or less, and the average aspect ratio (major axis / minor axis) is 1.5 to 10. Of potassium titanate can be obtained. Moreover, when the temperature increase rate is 2 ° C. to 5 ° C./min and the temperature increase rate is 1000 to 1300 ° C., potassium titanate having an average minor axis of 1 μm to 3 μm and an average major axis of 3 μm to 5 μm may be obtained. it can.

  According to the present invention, production of a fiber-shaped alkali titanate is suppressed, and a plate-like or columnar alkali titanate having a relatively short minor axis (preferably having an average diameter of 3 μm or more) is easily and inexpensively produced. Can do. In the present invention, the aggregate or granulated titanium compound and the alkali metal compound such as a potassium compound are first uniformly ground and mixed in a vibration mill, particularly a vibration lot mill, so that the subsequent firing reaction proceeds uniformly. For this reason, it becomes possible to obtain the alkali titanate of the target composition, especially potassium 4 titanate or / and 6 potassium titanate, without performing the component adjustment step after the firing reaction. In addition, friction materials containing this material are stable over a wide temperature range from low to high temperatures and have excellent friction coefficient and wear resistance, so they are used in automobiles, railway vehicles, aircraft, various industrial equipment, etc. When used as a brake member material, for example, a clutch fading material and a brake material such as a brake lining or a disk pad, the braking function is improved, stabilized, and the service life is improved.

Hereinafter, the manufacturing method of the alkali titanate concerning this invention is demonstrated in detail.
The titanium compound used in the production method of the present invention is, for example, titanium dioxide, titanium suboxide, orthotitanic acid or a salt thereof, metatitanic acid or a salt thereof, titanium hydroxide, peroxotitanic acid or a salt thereof alone or in combination. Can be used in combination of two or more. Among these, titanium dioxide is preferable. This is because it is excellent in miscibility and reactivity with the alkali metal compound and is inexpensive. The crystal form is preferably a rutile type or anatase type. In particular, when rutile type titanium dioxide is used, the resulting alkali titanate crystals are preferable.

  In the present invention, aggregates or granules of these titanium compounds are used as raw materials. Among these, an aggregate (including granules) or a granulated body of titanium dioxide is particularly preferable, and the average particle size is preferably 0.1 mm or more, more preferably 0.5 to 10 mm, and further preferably 0.5 to 1 mm. It is. If the average particle size is too small, it cannot be uniformly mixed with the alkali metal compound, and in order to mix more uniformly, when mixed with a mill having a high pulverization energy such as a vibration mill, it is fixed and mixed. This is because it becomes difficult. On the other hand, if it is too large, uniform mixing becomes difficult and the efficiency becomes poor. However, even a large aggregate or granulated body exceeding 10 mm can be used as an aggregate or granulated body of the titanium compound of the present invention by making it 10 mm or less by crushing and pulverizing.

Here, the aggregate in the present invention is a secondary particle in which primary particles are aggregated, a tertiary particle in which secondary particles are aggregated, and / or an n + 1 primary particle in which more n-order particles are aggregated (n is 3 or more). An integer) or the like formed with coarse particles (including granules), and an average particle diameter of 0.1 mm or more and 10 mm or less. On the other hand, since the primary particles are usually difficult to monodisperse, such as titanium dioxide powder having an average particle size of about several μm (at most about 20 μm) or aggregates of titanium dioxide powder, secondary particles are formed. It does not include such things. However, the agglomerate of the present invention may contain a small amount of such titanium dioxide powder (a small amount that does not hinder uniform mixing).
Here, an SEM photograph of a titanium oxide aggregate preferably used in the present invention is shown in FIG. 1, and an SEM photograph of a conventional commercially available titanium oxide powder (for pigment) is shown in FIG.

  In addition, the average particle size of the aggregate or granulated titanium compound in the present invention refers to a value measured according to a JISK0069 chemical product screening test method. In the present specification, the average particle diameter of the aggregate or granule is measured by this method unless otherwise specified.

  Such titanium dioxide aggregates are produced from titanium sulfate or titanyl sulfate (sulfuric acid method titanium oxide), or produced by oxidizing or hydrolyzing titanium tetrachloride in the gas phase (gas phase method titanium oxide). ), Or by neutralizing or hydrolyzing a titanium tetrachloride aqueous solution or alkoxy titanium. In particular, usually, in the production process before making the final product such as titanium oxide for pigments, the aggregated particles are pulverized, crushed or classified to adjust the particle size and remove coarse particles. It is preferable to use an intermediate product before this treatment, so-called clinker. That is, these clinker is a preferred aggregate of the titanium compound of the present invention, and by using the aggregate as a raw material, it is possible to uniformly mix the mixture by suppressing sticking of the mixture during pulverization and mixing with the alkali metal compound. As a result, it is possible to produce a desired alkali titanate without undergoing treatment such as component adjustment of the raw material.

  Further, instead of the aggregate of titanium compound, a granulated body of titanium compound may be used. Such a granulated body can be produced by granulating commercially available fine titanium oxide by spray drying, adding a binder, kneading and granulating, or the like. By using such a granulated body of a titanium compound as a raw material, even if a mechanical mixing means such as a vibration mill with a high pulverization energy is employed, adhesion or sticking to the inner wall of the vibration mill can be suppressed. As a result, the titanium compound and the alkali metal compound can be uniformly mixed as in the above-described aggregate titanium compound.

In the present invention, when the alkali titanate is produced, the mixing ratio of the raw materials is set to 1 mol of alkali titanate (M ₂ O · nTiO ₂ ): M is an alkali metal formed after the alkali metal compound is subjected to the firing reaction. The aggregate or granulated titanium compound is 0.5 to 10 mol, preferably 1 to 8 mol, as a titanium atom, and the alkali metal compound is 1 to 3 mol, preferably 1.5 to 2 as an alkali metal atom. .5 moles. In particular, in the case of producing potassium tetratitanate, when 1 mole of potassium tetratitanate (K ₂ O · 4TiO ₂ ) produced after the baking reaction is 1 mol, the titanium dioxide aggregate or granule is used as a titanium atom. It is 3.5 to 4.5 mol, preferably 3.8 to 4.2 mol, particularly preferably 4.0 mol, and the potassium compound is 1.8 to 2.2 mol, preferably 1.9, as a potassium atom. -2.1 mol, particularly preferably 2 mol. In the case of producing potassium 6 titanate, when 1 mole of potassium 6 titanate (K ₂ O · 6TiO ₂ ) produced after the calcination reaction is 1 mol, the titanium dioxide aggregate or granule is used as a titanium atom. 5 to 6.6 mol, preferably 5.8 to 6.2 mol, particularly preferably 6.0 mol, and the potassium compound is 1.8 to 2.2 mol, preferably 1.9 to 2, as a potassium atom. .1 mol, particularly preferably 2 mol. At this time, as described later, when adding metal titanium powder or titanium hydride powder to a mixture of titanium compound and alkali metal compound in an aggregate or granulation, the metal titanium powder or titanium hydride powder is oxidized and titanium dioxide. Therefore, it is necessary to adjust the mixing ratio by including the metal titanium powder or titanium hydride powder as a titanium source of the titanium compound in the aggregate or granulated body.

  In the present invention, the composition of the alkali titanate that is the final product can be controlled simply by adjusting the raw material ratio in this way. In the conventional method, when the titanium compound and the alkali metal compound are reacted, the alkali metal compound is used in excess of the theoretical amount because the reactivity is low and the alkali metal compound is lost. However, in the method of the present invention, an alkali titanate having a target composition is obtained by mixing a titanium compound and an alkali metal compound having a theoretical amount almost the same as the final composition of the target alkali titanate and performing a firing reaction using them as raw materials. be able to.

  As a mixing method in the present invention, either a dry mixing method or a wet mixing method can be adopted, but the dry mixing method is preferable from the viewpoint of simplifying the process. However, as a mixing means used for mixing, a conventional V-type blender, ball mill, or the like cannot sufficiently uniformly mix the titanium compound and the alkali metal compound in the aggregate or granulated body. For this reason, it is desirable to employ mechanical grinding means such as a vibration mill, a vibration rod mill, a vibration ball mill, a bead mill, a turbo mill, and a planetary ball mill. Particularly preferred is a vibrating rod mill filled with rod-shaped rods as grinding media. In the vibrating rod mill, the titanium compound and the alkali metal compound in the aggregate or granulated material are mixed while being pulverized to pulverize a powder having a large particle size between the rods, while excessively pulverizing a finer powder like a ball mill. There are few things. In particular, titanium oxide has strong adhesion due to hydroxyl groups originally present on the surface, and the specific surface area increases as the particle size decreases, and when pulverized, the pulverized material is easily fixed inside the vibration mill. In the present invention, such sticking of the pulverized material is suppressed, and uniform pulverization and mixing can be achieved as compared with other mixing methods. In particular, when using titanium dioxide aggregate or granulated material as a raw material as an aggregate of titanium compound as described above, and pulverizing and mixing with a vibrating rod mill, the coarse particles of titanium dioxide are pulverized and crushed. Overpulverization of primary particles that are fine to some extent is suppressed. As a result, sticking of titanium dioxide inside the mill is suppressed, and uniform mixing can be achieved. On the other hand, when a powder such as a titanium dioxide pigment is used as a raw material, fine primary particles are easily over-pulverized, easily fixed, and uniform mixing is difficult. In addition, when titanium ore such as ilmenite is used as a raw material, it is difficult to control the composition of alkali titanate, and therefore it is preferable to use pure titanium dioxide.

  In the present invention, the expression “uniform” refers to the case where the aggregate or granulated titanium compound in the present invention is not used as a raw material, for example, a pigment such as titanium dioxide powder is used as a raw material, and this is mixed with an alkali metal compound. This indicates that the raw material is uniformly dispersed as compared with the case of the above. Or it represents that the raw material is uniformly distributed compared with the case where it mixes with the vibration mill in this invention, especially a vibration rod mill, for example compared with the case where it mixes with the conventional V-type blender, a ball mill, etc.

  Further, when a titanium compound and an alkali metal compound are pulverized and mixed in a vibration mill, particularly a vibration lot mill, it is desirable to add an appropriate amount of alcohol. The amount of alcohol added is 0.1 to 3.0% by weight with respect to the weight of all pulverized products, including titanium compounds and alkali metal compounds, and additives such as anti-agglomeration agents to be described later. It is preferable to set it as 3 to 1.0 weight%. Further, it is preferable that the pulverization and mixing be performed at a temperature equal to or higher than the boiling point of the alcohol to which the temperature inside the mill is added, and the pulverization and mixing be performed while the alcohol is vaporized. Thereby, adhesion and adhesion of the titanium compound inside the mill can be suppressed, and a mixture in which the aggregate of the titanium compound and the alkali metal compound are more uniformly dispersed can be obtained. Alcohols include methanol, ethanol, amyl alcohol, allyl alcohol, propargyl alcohol, ethylene glycol, propylene glycol, erythrol, 2-ptene-1,4-diol, glycerin, pentaerythritol, arabit, sorbit, peptide. , Polyethylene glycol, polypropylene glycol, polyglycerin and the like. Of these, methanol and ethanol having a relatively low boiling point are preferred.

  Furthermore, an additive such as an anti-agglomeration agent or a lubricant may be added to suppress aggregation and adhesion of the titanium compound in a mixing container such as a vibration mill. The additive is preferably an additive that does not remain in the generated alkali titanate by decomposition, combustion, or vaporization when the titanium compound and alkali metal compound mixture is fired. Examples of such additives include celluloses, fatty acids, saccharides, cereals, ureas, polymers, and the like. Specifically, sugars such as methylcellulose, lignin, wood powder, pulp powder, natural fiber powder, stearic acid, ammonium stearate, sorbitan distearate, xylose, glucose, galactose, sucrose, starch, dextrin, wheat flour, soybean Powder, rice flour, sugar, urea, biurea, semicarbazide, guanidine carbonate, aminoguanidine, azodicarbonamide, acrylic resin powder, polypropylene powder, polyethylene powder, polystyrene powder, etc. Some wood powder, pulp powder and natural fiber powder are preferred.

  As a mixing method in the present invention, when a wet mixing method is used, pure water, a normal organic solvent such as alcohol, acetone, MEK, or THF is used as the solvent, but the dispersibility of the mixed powder is improved. In order to mix uniformly, it is preferable to use a surfactant and a dispersant in combination.

  Further, if necessary, the mixture of the aggregate or granulated titanium compound and alkali metal compound may further contain metal titanium powder or titanium hydride powder. In this case, it is preferable to set it as 0.01-0.2 mol with respect to 1 mol of titanium atoms in a titanium compound, Furthermore, it is preferable to set it as 0.03-0.1 mol. When titanium titanium powder or titanium hydride powder is blended in this way, it can be burned at the same time in the reaction vessel to suppress the occurrence of temperature distribution inside the reaction vessel, and the reaction can be performed more uniformly. An alkali titanate having a desired composition can be obtained.

The alkali metal compound of the present invention is preferably one or more metals selected from potassium, sodium and lithium compounds. In particular, a potassium compound which is a raw material of potassium titanate useful as a friction modifier is preferable. Moreover, a lithium compound which is a raw material of lithium titanate useful as an electrode material for a lithium ion secondary battery is also preferably used. The alkali metal compounds are carbonates, hydroxides, oxalates and the like of these, and those that melt in the firing reaction are preferred, and carbonates or hydroxides are particularly preferred. These are preferable because they are easily melted or decomposed in the calcination reaction with the titanium compound, and the reaction easily occurs, and carbon dioxide gas, water, etc. are generated after the decomposition, and no impurities remain in the product. When producing potassium titanate, potassium oxide, potassium carbonate, potassium hydroxide, potassium oxalate, or the like is used as the potassium compound, and potassium carbonate is preferably used. These potassium compounds can be used alone or in combination of two or more. When producing sodium titanate, sodium carbonate, sodium hydroxide, sodium oxalate, or the like is used as the sodium compound, preferably sodium carbonate. When manufacturing lithium titanate, they are lithium carbonate and lithium hydroxide, and lithium carbonate is preferable. In the present invention, when potassium titanate is produced, a titanium compound such as titanium oxide and a potassium compound such as potassium carbonate are mixed to perform a baking reaction. In this case, the shape of the obtained potassium titanate is preferably controlled by mixing a lithium compound such as lithium carbonate with the potassium compound. In addition, addition of an alkaline earth metal compound such as a magnesium compound or a barium compound is also preferable because the formation of fibrous crystals can be suppressed. It should be noted that other compounds, such as inorganic oxides, may be added in a minute amount so as not to affect the production of alkali titanate. As the inorganic oxide, for _{example, CeO 2, WO 3, ZrO} 2, Zr (CO 3) 2, etc. CaCO ₃ and the like.

  The uniform mixture of the aggregate or granulated titanium compound and alkali metal compound obtained as described above is fired to react the titanium compound and the alkali metal compound. Thereby, a rod-like, columnar, columnar, strip-like, granular and / or plate-like alkali titanate is obtained. Firing is performed in a reaction vessel, or a binder is added to the mixture to form a molded body, which is directly fired. In consideration of the reactivity and the shape of the alkali alkali titanate obtained, it is preferable to fill the reaction vessel with the entire mixture and to fire.

  The reaction vessel for firing is preferably made of ceramics and is made of a normal ceramic material such as alumina, and when the above mixture is placed or charged, it is difficult for air to enter between the mixture. Is used. Specific examples include a cylindrical object, a columnar object having a recess, a rectangular object having a recess, a dish-like object, and the like. Among these, a cylindrical or rectangular object having a certain depth of recesses formed in a part of these is preferable in order to prevent infiltration of oxygen in the air during firing.

  Further, when filling the ceramic reaction vessel with the mixture, it is preferable to interpose a sheet material made of carbonized material at least at the bottom of the ceramic reaction vessel between the ceramic reaction vessel and the mixture. In this way, by interposing the sheet material, the alkali metal compound in the mixture melts at the time of firing, the alkali metal compound is lost, or the molten alkali metal compound penetrates into the ceramic reaction vessel. Can be avoided. Moreover, when these sheet materials are interposed at least in the inner wall portion formed by the concave portion of the ceramic reaction vessel in contact with the mixture, the loss of potassium compounds and the penetration into the ceramic reaction vessel can be avoided more reliably. It is more preferable because it is possible. Furthermore, it is particularly preferable that these sheet materials are interposed in the entire inner wall portion formed by the concave portion of the ceramic reaction vessel because the loss of the alkali metal compound and the penetration into the ceramic reaction vessel can be avoided almost completely.

  The sheet material made of carbonized material is carbonized when fired and finally burned out, and is made of a material that does not generate softened or fluidized material when fired. Fiber, bark or thermosetting resin is used. For example, in the case of paper, ordinary paper that is hard to be carbonized and softened such as vinyl chloride that is softened is used, and so-called unbleached kraft paper, double-bleached kraft paper, packaging such as single gloss bleach Information paper such as paper, cardboard base paper, newspaper paper, high-quality paper, medium-quality paper, recycled paper, book paper, cast-coated paper, art paper, PPC paper, and the like are used. Moreover, as natural fiber, cotton, hemp, silk, etc. are used, for example. Moreover, as a thermosetting resin, a phenol resin, an epoxy resin, a melamine resin etc. are used, for example. The shape of the sheet material is a sheet, a woven fabric, a non-woven fabric, or a bag.

The firing temperature varies depending on the type and crystal form of the alkali titanate, but in the case of potassium titanate, it is usually 800 to 1300 ° C, preferably 1000 to 1300 ° C. The shape of the obtained potassium titanate can be controlled by adjusting the firing temperature, and larger potassium titanate can be obtained by performing the firing temperature at a higher temperature. However, when the temperature is lower than 800 ° C., the reaction does not proceed sufficiently. Further, firing at a high temperature exceeding 1300 ° C. requires a furnace capable of withstanding it, which is expensive and close to the melting point of potassium titanate, making it difficult to control the shape and 1300 ° C. The following firing is preferred. In the case of Li ₄ Ti ₅ O ₁₂ having a spinel crystal structure in lithium titanate, the temperature is usually 800 to 1000 ° C., preferably 850 to 950 ° C. In the case of _Li 2 TiO ₃ is also usually 950 to 1,450 ° C., preferably from 950 to 1200 ° C.. In the case of 6 sodium titanate, the temperature is usually 400 to 900 ° C, preferably 500 to 800 ° C. Moreover, baking time is 1 to 10 hours in the said temperature range, Preferably it is 2 to 5 hours. Although it cools to normal temperature after a baking reaction, a temperature increase rate is 0.5-10 degree-C / min from room temperature to the said baking temperature, Preferably it carries out at the rate of 0.5-5 degree-C / min. The cooling rate is 0.5 to 10 ° C./min, preferably 1 to 5 ° C./min, from the baking temperature to 300 ° C. Thus, the alkali titanate of this invention can be obtained by adjusting a calcination temperature, a temperature increase rate, and a cooling rate. In particular, in the method for producing potassium titanate according to the present invention, by using such a firing temperature, a relatively slow temperature increase rate and a relatively slow cooling rate, the growth of potassium titanate particles is promoted and shortened. A rod-like, columnar or plate-like crystal having a large diameter can be obtained. Especially, the length of an average minor axis is controllable by adjusting a calcination temperature and a temperature increase rate. For example, when the firing temperature is 1000 ° C. to 1300 ° C. and the rate of temperature rise is 0.5 to 2 ° C./min, potassium titanate having an average minor axis of 3 μm or more and 10 μm or less can be obtained. Here, the average minor axis of the obtained potassium titanate increases as the temperature increases with respect to the firing temperature and as the rate of temperature increase decreases. It should be noted that when the temperature rising rate is higher than 2 ° C./min, in particular, when the temperature rising rate is 2 ° C. to 5 ° C./min, potassium titanate having an average minor axis of 1 μm or more and 3 μm or less can be obtained.

  The alkali titanate obtained as described above is mechanically crushed or pulverized as necessary. In particular, in the case where fibrous potassium titanate having a minor axis of 3 μm or less and a major axis of 5 μm or more is contained, it is preferable to crush those having a major axis of 5 μm or more to be less than 5 μm. Here, known means can be adopted as the means for mechanically crushing or crushing, and a vibration mill, a vibration ball mill, a bead mill, a turbo mill, a planetary ball mill, and the like are used. If necessary, the alkali titanate after pulverization or pulverization is classified or sieved. In particular, when fibrous potassium titanate is included, classification or sieving is preferably performed in order to remove those having a minor axis of 3 μm or less or powders.

  The alkali titanate such as the fiber-like, rod-like or columnar potassium titanate may be aggregated, granulated or massive. By using an agglomerate or the like, handling of the alkali titanate itself becomes very easy, and scattering and suction to the work environment can be prevented. These average diameters are 20 to 200 μm, preferably 50 to 100 μm. When blended with other components as a friction material to be described later, the agglomeration is dissolved so that the rod-like or columnar alkali titanate is uniformly dispersed. Preferably it is. Here, the average diameter means a value obtained by measuring the diameters of about 200 by image analysis of scanning electron micrographs and averaging the diameters. The alkali titanate of the aggregate may be the aggregate after the baking reaction described above, and the aggregate is mechanically crushed or pulverized so as to be in the above diameter range, and sieved or classified as necessary. May be prepared. Alternatively, the alkali titanate obtained by firing may be pulverized or pulverized, and then added with a solvent and milled by spray drying or the like to prepare an aggregate, granule or mass.

  As described above, the method for producing an alkali titanate of the present invention has high crystallinity and purity because the aggregated or granulated titanium compound and the alkali metal compound are pulverized and uniformly mixed and then subjected to a firing reaction. An alkali titanate compound having a desired composition is obtained. In particular, in the production of potassium titanate, the target potassium titanate, 6 potassium titanate, or a mixture thereof can be directly subjected to the firing reaction without adjusting the components such as pH adjustment and acid washing, which has been conventionally performed after the firing reaction. Can be manufactured by. The potassium titanate obtained by such a method of the present invention has an average minor axis (or average thickness) of 3.0 to 10 μm and an average aspect ratio (major axis / minor axis) of 1.5 to 10. It has a certain rod shape, columnar shape, columnar shape, strip shape or plate shape. Here, the average minor axis and the average length (average major axis) were measured by image analysis of scanning electron micrographs, and the particle diameters of about 200 particles were measured and averaged (referred to below). The average minor axis and average length (average major axis) in the described examples were also measured in the same manner). Similarly, the average aspect ratio is obtained by measuring the average minor axis and the average length (average major axis) with a scanning electron microscope and calculating the ratio. It is also a preferred embodiment that the potassium titanate is mechanically crushed or pulverized and the aspect ratio is adjusted to less than 3, preferably less than 2.5. It is also possible to obtain potassium titanate having an average minor axis of 1 to 3 μm by adjusting the heating rate in addition to the firing temperature. In this case, the average minor axis is as short as 3 μm or less, but if necessary, the average major axis can be 3 μm to 5 μm by crushing or grinding, and potassium titanate within the WTO recommended range is obtained. be able to.

The potassium titanate produced by the method of the present invention is represented by the general formula K ₂ O · nTiO ₂ (where n is an integer of 1 to 12), preferably n is 2, 4, 6 And n is particularly preferably potassium tetratitanate with n = 4, potassium hexatitanate with n = 6, or a mixture thereof. These are because when they are used as friction modifiers, they are excellent in heat resistance, and the production of potassium titanate having a fibrous shape can be reduced.

  Further, among the alkali titanates of the present invention, potassium titanate has a powder shape in addition to the specific shape described above, that is, potassium titanate having a rod shape, columnar shape, columnar shape, strip shape, plate shape, or the like. It may be a mixture with potassium titanate. By making a mixture of powdery potassium titanate, the fluidity is further improved, and when this is used in a friction material, it can be dispersed relatively uniformly, and as a result, the heat resistance of the friction material can be improved. it can.

  The alkali titanate such as potassium titanate thus obtained can be used as a friction modifier for the friction material. The blending amount of the alkali titanate in the friction material is preferably 3.0 to 50% by weight. If the amount is less than 3.0% by weight, the effect of improving the friction and wear characteristics may not be exhibited. If the amount exceeds 50% by weight, no further improvement in the effect of the friction and wear characteristics can be expected, which is economically disadvantageous. It is to become.

  As a specific example of the friction material of the present invention, for example, a friction material comprising a base fiber, a friction modifier and a binder can be exemplified. As a mixing ratio of each component in the friction material, 1 to 60 parts by weight of a base fiber, 20 to 80 parts by weight of a friction modifier (including alkali titanate such as potassium titanate), and 10 to 40 parts by weight of a binder. And 0 to 60 parts by weight of other components.

  Examples of the base fiber include resin fibers such as aramid fibers, metal fibers such as steel fibers and brass fibers, carbon fibers, glass fibers, ceramic fibers, rock wool, wood pulp, and potassium titanate fibers. These base fibers may be used after being subjected to a surface treatment agent such as a silane coupling agent, a titanate coupling agent, or a phosphate ester in order to improve dispersibility and adhesion to the binder.

  As the friction modifier in the friction material of the present invention, in addition to the potassium titanate of the present invention, other friction modifiers may be used in combination as long as the effects of the present invention are not impaired. For example, organic powder such as vulcanized or unvulcanized natural, synthetic rubber powder, cashew resin powder, resin dust, rubber dust, carbon black, graphite powder, molybdenum disulfide, barium sulfate, calcium carbonate, clay, mica, talc, Examples thereof include diatomaceous earth, antigolite, sepiolite, montmorillonite, zeolite, metal powder such as copper, aluminum, zinc and iron, and oxide powder such as alumina, silica, chromium oxide, titanium oxide and iron oxide.

  As binders, thermosetting resins such as phenol resin, melanin resin, epoxy resin, acrylic resin, DAP (diallyl phthalate) resin, urea resin, natural rubber, nitrile rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber, poly Examples include rubbers such as isoprene rubber and polymer elastomers, elastomers, polyamide resins, polyphenylene sulfide resins, organic resins such as thermoplastic resins such as polyimide resins and thermoplastic liquid crystalline resins, and inorganic binders such as alumina sol and silica sol.

  In addition to the above components, the friction material of the present invention may contain components such as a rust inhibitor, a lubricant, and an abrasive as necessary. There is no restriction | limiting in particular in the case of manufacture of the friction material of this invention, According to the manufacturing method of a conventionally well-known friction material, it can manufacture suitably.

  As an example of the method for producing a friction material according to the present invention, a base material fiber is dispersed in a binder, and a friction material composition is blended by combining a friction modifier and other components blended as necessary. An example is a method in which the composition is adjusted, and then the composition is put into a mold and heated under pressure to perform binder molding.

  As another example, the binder is dissolved and kneaded in a twin-screw extruder, and the side fiber is combined with the base fiber, the friction modifier, and other components blended as necessary, and after extrusion molding. An example of the method for machine-fiber processing into a desired shape can be given.

  As yet another example, the friction material composition is dispersed in water, etc., and is made on a papermaking net, dehydrated and made into a short shape, and then heated and pressed with a press machine to form a binder. An example is a method of appropriately cutting and polishing the obtained friction material to obtain a desired shape.

  The method for producing an alkali titanate according to the present invention can simplify the production process and is advantageous in terms of cost. In addition, potassium titanate that can be produced is advantageous in terms of fluidity because it has few fiber shapes and has a specific shape such as a rod, column, column, strip, or plate, and was used as a friction material In this case, it is stable over a wide temperature range from a low temperature to a high temperature range and has an excellent friction coefficient and wear resistance. Therefore, a material for a brake member used in automobiles, railway vehicles, aircraft, various industrial equipments, etc., for example, a clutch It is suitable for fading materials and brake materials such as brake linings and disc pads. In addition, when lithium titanate is produced by the method of the present invention, since the raw material titanium compound and lithium compound can be uniformly mixed, lithium titanate having a desired composition can be obtained at low cost. A material suitable for the electrode material can be provided.

  Next, the present invention will be described more specifically with reference to examples. However, this is merely an example, and the present invention is not limited thereto.

Example 1
Aggregate titanium oxide (FIG. 1) 8.7 kg, pulverized potassium carbonate 2.7 kg, titanium powder 447 g and wood chips 897 g with an internal volume of 250 liters, a diameter of 19 mm, a length of 1430 mm, 3200 g / Rod, filled into a vibration mill (Chuo Kako Co., Ltd., trade name FV250) filled with 3010 kg of cylindrical rod media made of SS, added with 65 g of methanol, amplitude 8 mm, frequency 1000 times / minute, internal temperature 80 The mixture was ground at 15 ° C. for 15 minutes to obtain a mixture. 500 g of the obtained mixture was filled in a ceramic reaction vessel having an open top, placed in an electric furnace, heated from room temperature to 1050 ° C. over 12 hours, and then in the range of 1000 to 1100 ° C. Baked for 5 hours. Then, it cooled to room temperature over 13 hours, and after cooling to normal temperature, this baked product was taken out. An SEM photograph of this fired product, ie, aggregated potassium titanate, is shown in FIG. Since this baked product is agglomerated, this baked product was crushed with a crusher (manufactured by Hosokawa Micron Corporation, Pulverizer) to obtain a baked product having a desired shape.

  The fired product thus obtained was rod-shaped, columnar, or cylindrical. The average minor axis was 3.0 μm, the average length (average major axis) was 5.9 μm, and the average aspect ratio was 1.97. Further, when the fired product was analyzed by X-ray diffraction, it was a single-phase crystal of potassium titanate and did not contain unreacted titanium oxide. Thus, in the production method of the present invention, potassium titanate having a desired composition can be produced by a simple method, and the shape is a range recommended by WHO (average minor axis is 3 μm or less, average fiber length is 5 μm or more. And other than the fibrous compound having an aspect ratio of 3 or more).

(Example 2)
Experiments were performed in the same manner as in Example 1 except that aggregate titanium oxide having an average particle size of 1.5 mm was used instead of aggregate titanium oxide having an average particle size of 0.8 mm. The fired product thus obtained had an average minor axis of 3.2 μm, an average length (average major axis) of 6.0 μm, and an average aspect ratio of 1.88. Further, when this was analyzed by X-ray diffraction, it was a single-phase crystal of potassium hexatitanate and did not contain unreacted titanium oxide.

(Example 3)
Agglomerated 7.2 kg of aggregate with an average particle diameter of 0.8 mm, 2.7 kg of powdered potassium carbonate, 350 g of titanium powder, and 897 g of wood chips, and 20010 kg of cylindrical rod media having an internal volume of 200 liters, a diameter of 19 mm and a length of 1430 mm The mixture was filled into a vibration mill, 65 g of methanol was further added, and the mixture was pulverized at an internal temperature of 80 ° C. for 15 minutes to obtain a mixture. 500 g of the obtained mixture was filled in a ceramic reaction vessel having an open top, placed in an electric furnace, heated from room temperature to 1050 ° C. over 12 hours, and then in the range of 1000 to 1100 ° C. Baked for 5 hours. Then, it cooled to room temperature over 13 hours, and after cooling to normal temperature, this baked product was taken out. Since the calcined product was agglomerated, the calcined product was pulverized with a pulverizer to obtain a desired size to obtain potassium titanate.

  The fired product thus obtained had an average minor axis of 3.2 μm, an average length (average major axis) of 6.2 μm, and an average aspect ratio of 1.9. When this fired product was analyzed by X-ray diffraction, peaks of potassium hexatitanate and potassium tetratitanate were observed, and it was found that this was a mixed composition of these two types of potassium titanate. Moreover, unreacted titanium oxide was not contained. As described above, in the production method of the present invention, a desired potassium titanate can be produced by a simple method, and many of the shapes are included in the range recommended by WHO.

Example 4
500 g of the same mixture as in Example 1 was filled in a ceramic reaction vessel having an open top, placed in an electric furnace, heated from room temperature to 1150 ° C., and then 5.5 to 1150-1200 ° C. Baked for hours. Then, after cooling to room temperature and cooling to room temperature, the fired product was taken out. The temperature increase rate and temperature decrease rate were the same as in Example 1. An SEM photograph of this fired product, ie, aggregated potassium titanate, is shown in FIG. Since the fired product is agglomerated, the fired product was crushed with a crusher to obtain a desired size.

  The shape of the fired product thus obtained was rod-shaped or columnar (including a size in which the major axis and the minor axis are almost the same). The average minor axis was 4 μm, the average length (average major axis) was 15 μm, and the average aspect ratio was 3.7. Further, when this fired product was analyzed by X-ray diffraction, it was found to be a single phase of potassium hexatitanate. Moreover, unreacted titanium oxide was not contained. Thus, in the production method of the present invention, potassium titanate having a desired composition and shape can be produced by a simple method.

(Example 5)
500 g of the same mixture as in Example 1 was filled in a ceramic reaction vessel having an open top, placed in an electric furnace, heated from room temperature to 1250 ° C., and then 5.5 to 1200 to 1300 ° C. Baked for hours. Then, after cooling to room temperature and cooling to room temperature, the fired product was taken out. The temperature increase rate and temperature decrease rate were the same as in Example 1. An SEM photograph of this fired product, ie, aggregated potassium titanate, is shown in FIG. Since the fired product is agglomerated, the fired product was crushed with a crusher to obtain a desired size.

  The shape of the fired product thus obtained was rod-shaped or columnar (including a size in which the major axis and the minor axis are almost the same). The average minor axis was 6 μm, the average length (average major axis) was 27 μm, and the average aspect ratio was 4.5. Moreover, the content rate included 50% or more of a thing with a minor axis of 3-10 micrometers and a major axis of 5-45 micrometers. That is, a relatively large rod-shaped or columnar fired product having an average minor axis of 5 μm or more and an average length (average major axis) of 20 μm or more was obtained. When this fired product was analyzed by X-ray diffraction, it was found to be a potassium hexatitanate single phase. Moreover, unreacted titanium oxide was not contained. As described above, in the production method of the present invention, a desired potassium titanate can be produced by a simple method, and many of the shapes are included in the range recommended by WHO.

(Example 6)
The experiment was performed in the same manner as in Example 1 except that 8.7 kg of titanium oxide of the aggregate of Example 1 was replaced with 8.9 kg of granulated material having an average particle diameter of 0.3 mm obtained by granulating commercially available titanium oxide by spray drying. Went. Also in this case, as in Example 1, as a result of X-ray diffraction, a single-phase crystal of potassium hexatitanate was obtained, and it was found that no unreacted titanium oxide was contained. Also, the shape has an average minor axis larger than 3 μm, and a shape within the range recommended by WHO was obtained.

  As described above, as can be seen from Examples 1 to 6 and FIGS. 3 to 5, the shape of the potassium titanate obtained by increasing the firing temperature can be increased. Specifically, when the firing temperature is increased from 1000 to 1100 ° C., from 1100 to 1200 ° C., and from 1200 to 1300 ° C., the average minor axis of the obtained potassium titanate increases to about 3 μm, 4 μm, and 6 μm, and the average length (average The major axis is also increased to about 6 μm, 15 μm, and 27 μm. Therefore, the potassium titanate having a desired shape can be obtained by adjusting the firing temperature. In addition, since the raw materials can be uniformly mixed in the production method of the present invention, unreacted titanium oxide is not included in the obtained fired product, and potassium titanate having a desired composition can be obtained simply by adjusting the raw material composition.

(Example 7)
The firing pattern in Example 1 was “heated from room temperature to 1050 ° C. over 7 hours, and then fired in the range of 1000 to 1100 ° C. for 5.5 hours. A fired product was obtained in the same manner as in Example 1 except that it was changed to “cooled”. Since the fired product was an agglomerate containing a large amount of fibrous potassium titanate having a minor axis of 3 μm or less and a major axis of 5 μm or more, the fired product was crushed to obtain a desired shape (a shape in a range recommended by WTO). A fired product T was obtained. FIG. 6 is an SEM photograph of potassium titanate, which is the fired product T.

  The fired product T thus obtained was rod-shaped, columnar, or cylindrical. The average minor axis was 1.9 μm, the average length (average major axis) was 4.1 μm, and the average aspect ratio was 2.3. Further, when the fired product was analyzed by X-ray diffraction, it was a single-phase crystal of potassium titanate and did not contain unreacted titanium oxide. Thus, in the production method of the present invention, potassium titanate having a desired composition can be produced by a simple method. In addition, although the minor axis of this potassium titanate has a shape of 3 μm or less, the average major axis is 5 μm or less, and the shape is a range recommended by WHO (average minor axis is 3 μm or less, average fiber length is 5 μm or more. And other than the fibrous compound having an aspect ratio of 3 or more).

(Example 8)
Aggregated titanium oxide (Fig. 1) 75.26 kg, powdered lithium carbonate 48.13 kg, titanium powder 2.21 kg and wood chips 3.72 kg, inner volume 250 liters, diameter 19 mm, length 1430 mm, 3200 g / rod, filled in a vibration mill (Chuo Kako Co., Ltd., trade name FV250) filled with 3010 kg of cylindrical rod media made of SS, added with 65 g of methanol, amplitude 8 mm, frequency 1000 times / minute The mixture was pulverized at an internal temperature of 80 ° C. for 15 minutes to obtain a mixture. 5 kg of the obtained mixture was filled in a ceramic reaction vessel having an open top, placed in an electric furnace, heated from room temperature to 1050 ° C. over 12 hours, and then in the range of 1000 to 1100 ° C. for 4 hours. Baked. Then, it cooled to room temperature over 15 hours, and after cooling to normal temperature, this baked product was taken out. This fired product was crushed with a crusher (manufactured by Hosokawa Micron Corporation, Pulverizer) to obtain a fired product having a desired shape. The fired product thus obtained had a flake shape and a size of 5 to 16 μm. Further, when analyzed by X-ray analysis, the composition was a single-phase crystal of Li ₂ TiO _{3 and} no unreacted titanium oxide was contained.

(Comparative Example 1)
Average particle diameter: 1.0 μm (The average particle diameter here was measured by image analysis of SEM photographs (measurement similar to the above-mentioned image analysis). The average particle size of the aggregate is excluded).) 8.7 kg of titanium oxide for pigment (shown in FIG. 2), 5.1 kg of powdered potassium carbonate, and 700 g of titanium powder are V-type blenders (manufactured by Tokuju Seisakusho) At room temperature for 15 minutes. The reason why the V-type blender was used here is that mixing is difficult when the same vibration mill as in Example 1 is used (see Comparative Example 2 below). 500 g of the obtained mixture was filled in a ceramic reaction vessel having an open top, placed in an electric furnace, and baked at 1100 ° C. for 3 hours. Then, it cooled to room temperature over 13 hours, and after cooling to normal temperature, this baked product was taken out. After the fired product was taken out, it was immersed in 3 liters of cold water to form a slurry, and the slurry was defibrated by a colloid mill (trade name Disper Mill, manufactured by Hosokawa Micron Corporation) to separate the fibrous material. After neutralizing the defibrated and separated slurry, it was filtered by a vacuum filtration method to obtain a cake-like substance. The cake-like substance was dried, heated to 800 ° C., and heat-treated for 30 minutes. In this way, single potassium 6-titanate fibers having an average fiber diameter of 0.5 μm and a fiber length of 50 μm were obtained. An SEM photograph of this potassium titanate fiber is shown in FIG.

(Comparative Example 2)
An experiment similar to that of Example 1 was performed except that the titanium oxide powder for pigment having an average particle diameter of 1.0 μm was used instead of the aggregate titanium oxide having an average particle diameter of 0.8 mm. However, in this case, when mixing, the titanium oxide powder was fixed to about 1/3 to 1/2 of the total titanium oxide in the vibrating rod mill, and mixing was difficult. That is, it was not possible to mix uniformly as compared with the above examples. And when the baked product obtained by baking this was analyzed by X-ray diffraction, it was a mixed phase crystal of titanium oxide, potassium titanate and potassium titanate, and unreacted titanium oxide remained. It was.

(Comparative Example 3)
8.7 kg of titanium oxide powder having an average particle diameter of 1.0 μm, 2.7 kg of powdered potassium carbonate, 447 g of titanium powder and 897 g of wood chips are charged into a V-type blender, and 65 g of methanol is further added, and mixed for 15 minutes. Got. 500 g of the obtained mixture was filled in a ceramic reaction vessel having an open top, placed in an electric furnace, heated from room temperature to 1050 ° C. over 12 hours, and then in the range of 1000 to 1100 ° C. Baked for 5 hours. Then, it cooled to room temperature over 13 hours, and after cooling to normal temperature, this baked product was taken out. The fired product was pulverized with a pulverizer (manufactured by Hosokawa Micron Corporation, Pulverizer) to obtain a desired shape.

  The fired product thus obtained had an average minor axis of 2.5 μm, an average length (average major axis) of 8.5 μm, and an average aspect ratio of 3.4. When analyzed by X-ray diffraction, the composition was a mixed phase crystal of titanium oxide, potassium titanate and potassium titanate, and unreacted titanium oxide remained.

(Comparative Example 4)
A V-type blender was charged with 9.1 kg of ilmenite powder, 2.7 kg of powdered potassium carbonate, 447 g of titanium powder, and 897 g of wood chips, and 65 g of methanol was further added, followed by mixing for 15 minutes to obtain a mixture. 500 g of the obtained mixture was filled in a ceramic reaction vessel having an open top, placed in an electric furnace, heated from room temperature to 1000 ° C. over 12 hours, and then in the range of 1000 to 1100 ° C. Baked for 5 hours. Then, it cooled to room temperature over 13 hours, and after cooling to normal temperature, this baked product was taken out. The fired product was pulverized with a pulverizer (manufactured by Hosokawa Micron Corporation, Pulverizer) to obtain a desired shape.

  The fired product thus obtained had an average minor axis of 2.7 μm, an average length (average major axis) of 8.6 μm, and an average aspect ratio of 3.2. When this was analyzed by X-ray diffraction, it was a mixed phase crystal containing 1.5% by weight of iron in addition to titanium oxide, potassium titanate, and potassium hexatitanate. That is, it contained unreacted titanium oxide and impurity iron.

(Comparative Example 5)
The experiment was performed in the same manner as in Example 1 except that the mixing was performed using a V-type blender instead of mixing using a vibration mill filled with a cylindrical rod medium. In this case, uniform mixing could not be performed, and the fired product obtained by firing reaction was analyzed by X-ray diffraction. As a result, it was a titanium oxide, potassium titanate and potassium titanate mixed phase crystal, and unreacted titanium oxide was It remained.

(Example 9) Preparation of friction material 15 parts by weight of potassium titanate obtained in Example 1, aramid fiber (trade name “Kevlar Pulp” length: 3.0 mm, manufactured by Toray DuPont Co., Ltd.), 3 parts by weight, bonding 10 parts by weight of additive (phenolic resin), 9 parts by weight of organic additive (cashew dust), 10 parts by weight of graphite lubricant, 8 parts by weight of copper powder, 30 parts by weight of barium sulfate Mix thoroughly and fill in the mold, and perform binding molding (pressing force; 150 kgf / cm2, temperature 170 ° C, 5 minutes), mold, release, and heat treatment (kept at 180 ° C for 3 hours) gave. Then, the grinding | polishing process was performed and the friction material of this invention was obtained. Note that organic additives, lubricants, and oxide powders that were normally added to friction materials were used.

Using the friction material obtained as described above, the friction performance as a brake pad was evaluated by a full size dynamo test of JASO (Automotive Engineers Association) C406, and the results are shown in Table 1. The test apparatus and measurement conditions were as follows.
Testing machine: Single-type full-size dynamo testing machine Testing conditions:
Vehicle: Toyota Camry Tire size: 185/70 / SR13
Effective tire radius: 287mm
Inertia: 44.1kg ・ m2
Front brake Model: PD51
Cylinder diameter: 51mm
Effective rotor radius: 96.5mm
Rotor dimensions: 243mm
Rotor thickness: 18.0mm
Format: Ventilated

(Example 10)
Using the potassium titanate obtained in Example 3, a friction material was prepared and evaluated in the same manner as in Example 9. The obtained results are listed in Table 1.

(Comparative Example 6)
Using the potassium titanate obtained in Comparative Example 1, a friction material was prepared and evaluated in the same manner as in Example 9. The obtained results are listed in Table 1.

  As a result, when the potassium titanate obtained by the method of the present invention is used as a friction material, the friction coefficient at each speed is high and the brake efficiency is high compared to conventional potassium titanate, and the friction coefficient between speeds. It can be seen that there is little drop in the stability (speed spread) and the friction performance as a brake pad is excellent.

It is a scanning electron micrograph of the titanium oxide of the aggregate concerning this invention. It is a scanning electron micrograph of a commercially available titanium oxide for pigment. It is a scanning electron micrograph of potassium titanate manufactured by the manufacturing method of the present invention. It is a scanning electron micrograph of potassium titanate manufactured by another baking condition by the manufacturing method of the present invention. It is a scanning electron micrograph of the potassium titanate manufactured on the other baking conditions by the manufacturing method of this invention. It is a scanning electron micrograph of the potassium titanate manufactured on the other baking conditions by the manufacturing method of this invention. It is a scanning electron micrograph of the potassium titanate fiber manufactured with the conventional manufacturing method.

Claims (14)

Titanate having an average particle size of the titanium compound of the following aggregates or granules 10mm above 0.1mm and an alkali metal compound is mixed by a vibration rod mill, to produce an alkali titanate by firing a mixture obtained by the mixing A method for producing an alkali titanate, wherein the titanium compound is titanium oxide. 2. The method for producing an alkali titanate according to claim 1, wherein the alkali metal compound is an alkali metal carbonate or hydroxide. The method for producing an alkali titanate according to claim 1 or 2, further comprising an additive for preventing sticking or aggregation when mixing. The said additive is alcohol, The manufacturing method of the alkali titanate of Claim 3 characterized by the above-mentioned. The method for producing an alkali titanate according to any one of claims 1 to 4, wherein the titanium titanium powder or the titanium hydride powder is further mixed in the mixing. The method for producing an alkali titanate according to any one of claims 1 to 5, wherein the alkali metal compound is a compound composed of at least one selected from potassium, sodium and lithium. The method for producing an alkali titanate according to any one of claims 1 to 5, wherein the alkali titanate is potassium tetratitanate and / or potassium 6 titanate. The method for producing an alkali titanate according to claim 7, wherein the baking is performed in a temperature range of 800 ° C to 1300 ° C. The method for producing an alkali titanate according to claim 7, wherein the baking is performed at a temperature rising rate of 0.5 ° C to 2 ° C / min and a baking temperature of 1000 ° C to 1300 ° C. The method for producing an alkali titanate according to claim 7, wherein the baking is performed at a temperature rising rate of 2 ° C to 5 ° C / min and a baking temperature of 1000 ° C to 1300 ° C. A method for producing an alkali titanate, wherein the alkali titanate obtained by the method according to claim 9 or 10 is milled to prepare an aggregate, granule or mass. The method for producing an alkali titanate according to claim 11, wherein the alkali titanate has a rod shape, a columnar shape, a columnar shape, a strip shape, or a plate shape. The alkali titanate obtained by the method according to claim 9 has an average minor axis of 3 μm or more and 10 μm or less, and an average aspect ratio of 1.5 or more and 10 or less. 11. The method for producing an alkali titanate, wherein the alkali titanate obtained by the method according to claim 10 has an average minor axis of 1 μm to 3 μm and an average major axis of 3 μm to 5 μm.