KR100229289B1 - Powder of titanium compounds - Google Patents

Abstract

The composite carbon particles of the present invention are obtained by mixing an alkaline earth metal titanate crystal represented by RTiO ₃ (wherein R is an alkaline earth metal) with a compound represented by M ₂ Ti _n O 2 _{n + 1} wherein M is an alkali metal and n is 2 to 6 Or a mixture of these two types of crystals and titanium dioxide (TiO ₂ ) crystals, and the powder composed of these particles is a mixture of RO ( wherein, R is an alkaline metal compound and, TiO ₂ or the heat that is in the alkaline earth metal compound to the RO by the alkaline-earth metal) or heated, M ₂ O (wherein, M is M ₂ O by an alkali metal) or heating from the titanium compound in TiO _2, Z≥X + mY (wherein, Z is the number of moles of TiO _2, X is the number of moles of RO, Y is the number of moles of M ₂ O, Z, X and Y are each a positive number, m is the Z> 6 when X + mY or 2 to 6 when X = X + mY), and the mixture is baked at 700 to 1300 占 폚 It is prepared as. Further, this powder is mixed with a binder resin and then molded to form a friction material.

Description

Titanium compound powder

TECHNICAL FIELD The present invention relates to a titanium compound powder, that is, a powder composed of an alkaline earth metal titanate and an alkali metal titanate. More particularly, the present invention relates to a powder for a brake lining, a disk pad, a clutch face, etc. used for a braking device for an automobile, a railway vehicle, The present invention relates to a composite titanium compound powder suitable for use as a base material of a friction material.

The friction material for a braking device is produced by dispersing a base material in a resin (phenol resin or epoxy resin) serving as a binder and optionally adding a friction / wear control agent (such as barium sulfate) to the dispersion to form a composition under heating and pressing .

Conventionally, Chrysotile asbestos fibers have been used as the base material. However, asbestos-based friction material is abraded and damaged due to an increase in the temperature of the friction surface, resulting in a fading phenomenon with a rapid decrease in friction coefficient Moreover, asbestos fibers are also pointed to the problem of carcinogenicity.

Thus, efforts have been made to develop alternative products for asbestos fibers.

Examples of usable as the base material include alkali metal titanate alkali metal salts represented by M ₂ Ti _n O 2 _{n + 1} (wherein M is an alkali metal such as K, Na, Li or Rb, and n is an integer of 2 to 8) (JP-A-191599/1986). Representative examples of such fibers include potassium titanate (K ₂ Ti ₆ O ₁₃ ).

The alkali metal titanate fiber is a synthetic inorganic compound having a layered crystal structure (for example, when n is 2, 3 or 4) or a tunneled crystal structure (when n is 6 or 8) and has strength, It is a material having excellent abrasion resistance and having a hardness suitable as a friction material. Such an alkali metal titanate is subjected to melt processing, that is, a mixture (TiO ₂ / M ₂ O molar ratio of about 2) of titanium dioxide and carbon alkaline metal is heated and melted and cooled to obtain an alkali metal 2-titanate (M ₂ Ti ₂ O ₅ ) Is formed, and the alkali metal ions are dissolved so that the chemical composition is adjusted, and the resultant is heat-treated to be converted into a crystal structure.

The friction material produced using the alkali metal titanate fiber as the base material is superior to the friction material using the asbestos fibers in the prior art, but it is desired to further improve the anti-fading characteristics and friction coefficient of these materials.

It has been proposed to use a combination of potassium titanate fibers and alumina-silica fibers to improve anti-fading properties and other properties, but the alumina-silica fibers have a hardness of Moh's hardness of about 7, It was not preferable for use because the polishing characteristics were excessive.

The alkaline earth metal titanate expressed by RTiO ₃ (R is an alkaline earth metal such as Ca, Ba, Sr, or Mg) can be used as a titanium compound excellent in strength, heat resistance, thermal insulation, abrasion resistance, and the like as an alkali metal titanate. These titanates are synthetic inorganic compounds having a perovskite crystal structure. For example, by mixing a barium compound powder with needle-like particles of titanium dioxide hydrate (JP-A-88030/1982), potassium hydrate potassium titanate (JP-A-113623/1980), a solution containing potassium titanate and an aqueous solution of a divalent metal compound in the form of a crystalline fiber is prepared by reacting a solution containing a powder or a titanium dioxide hydroxide with a divalent metal ion in a closed vessel or a hydrothermal state (JP-A-21799/1987), an inorganic or organic compound of an alkali metal and an effluent (for example, a halide of an alkali metal) of a titanic acid such as potassium 2-titanate or potassium 6-titanate serving as a titanium source (JP-A-164800/1990), or by heat treatment (JP-A-16917/1991) by depositing an alkaline earth metal carbonate on the surface of the fibrous titanium dioxide compound acting as a starting material and mixing it with an alkali metal salt and heating.

The friction material produced by using the alkaline titanium titanate powder as the base material has the drawback that the wear characteristics of the other is excessively high although the friction coefficient is high.

In a study on the improvement of the method for synthesizing the titanium compound, the inventors of the present invention have found that when a powder composed of a crystal of an alkaline earth metal titanate and another titanium compound particle composed of an alkali metal titanate is used as a starting material It has been succeeded in producing by a relatively simple method and this powder is very useful as a base material of friction material, for example, to provide a friction material having a high friction coefficient, The present invention has been accomplished on the basis of these findings.

The present invention is characterized in that the particles composed of the composite titanium compound powder are each composed of a mixture of crystals of an alkaline earth titanate expressed by RTiO ₃ (wherein R is an alkaline earth metal such as Ca, Ba, Sr or Mg) and M ₂ Ti _n O 2 _{n + 1} (Wherein M is an alkali metal such as Li, Na, K or Rb, and n is an integer of 2 to 6), and a fine lump of these two kinds of crystals It is upper body.

The particles made of the composite titanium compound powder of the present invention are each composed of a crystal of an alkaline earth metal titanate represented by RTiO ₃ (wherein R is an alkaline earth metal) and an oxide of M ₂ Ti _n O 2 _{n + 1} wherein M is an alkali metal , n is a fine lumpy body composed of a crystal of an alkali metal titanate represented by an integer of 2 to 6 and a titanium dioxide (TiO ₂ ) crystal, and these three kinds of crystals are mixed with each other.

Composite titanium compound powder of the present invention, RO and an alkaline earth metal compound to RO by (wherein, R is an alkaline earth metal) or heated, M ₂ O is a M ₂ O by (wherein, M is an alkali metal) or heating from alkali metal compound and a titanium compound in TiO ₂ or TiO ₂ by heating, Z≥X + mY (wherein, Z is the number of moles of TiO _2, X is the number of moles of RO, Y is the number of moles of M ₂ O, Z, X And Y are each a positive number, m is 6 when Z> X + mY, or 2 to 6 when X = X + mY), and the mixture is heat-treated at 700 to 1300 ° C , And baking treatment.

When the ratio of the raw material components is adjusted so as to be Z = X + mY (m is 2 to 6), powders each composed of particles of fine lumpy bodies are obtained as heating reaction products, and the lumps are composed of alkaline earth titanate (RTIO ₃ ) And a crystal of an alkali metal titanate (M ₂ Ti _n O 2 _{n + 1} ) are mixed. Further, when the component is adjusted to be Z > X + 6Y, the heating reaction provides a powder composed of fine lumpy particles each further comprising titanium dioxide (TiO ₂ ) crystals when the two kinds of crystals are mixed .

Further, the present invention is characterized in that a crystal of an alkaline earth metal titanate represented by RTiO ₃ (R is an alkaline earth metal) and a crystal of M ₂ Ti _n O 2 _{n + 1} (wherein M is an alkali metal and n is an integer of 2 to 6) Or a mixture of these two kinds of crystals and a titanium dioxide (TiO ₂ ) crystal is formed on the surface of the friction material.

FIG. 1 is an electron micrograph (× 2000) of composite titanium compound particles in the form of fine lumps formed by mixing calcium titanate crystals and potassium titanate crystals.

FIG. 2 is an electron micrograph (× 8000) in which the composite titanium compound particles of FIG. 1 are magnified,

3 shows an electron micrograph (× 2000) of particles consisting of a single phase of calcium titanate,

The fourth is an electron micrograph (× 2000) of particles consisting of a single phase of potassium titanate,

Preparation of Composite Titanium Compound Powder

The powder of the present invention composed of the titanium compound is produced by the following process.

Powder of the invention made of a composite titanium compound particles, RO and an alkaline earth metal compound to RO by (wherein, R is an alkaline earth metal) or heated, M ₂ O M ₂ by (wherein, M is an alkali metal) or heating O, and TiO ₂ or a titanate which is converted to TiO ₂ by heating.

Examples of the alkaline earth metal compound that can be used as RO by RO or by heating include oxides, carbonates, sulfates, nitrates, halides (e.g., chlorides and fluorides) such as Ca, Ba, Sr and Mg, .

M ₂ O or as being useful as the alkali metal compound to the M ₂ O when heated, the oxides such as Li, Na, K, Rb, carbonate, sulfate, nitrate, halide (e.g., chlorinated and fluorinated products) , Hydroxides, and the like.

In addition, to be useful as the titanium compound in TiO ₂ by TiO ₂ or by heating, there is a refined anatase (anatase) powder, refined rutile powder and various other compounds (halides, sulfates, nitrates, hydroxides, etc.).

The raw material powder mixture is prepared by mixing an alkaline earth metal compound, an alkali metalized compound and a titanium compound with Z? X + mY wherein Z is the number of moles of TiO ₂ , X is the number of moles of RO, Y is the number of moles of M ₂ O, Y is each a positive number, m is 6 when Z> X + mY, or m is 2 to 6 when Z = X + mY). More specifically, the ratio of the amount of the titanium compound calculated by the mole number is calculated by adding the amount of the amount consumed by the reaction by RO (RTiO ₃ formation reaction) and the reaction by M ₂ O (M ₂ T _n O _{2n + 1} formation reaction) Correspondingly or more than this amount.

The raw material powder mixture may be calcined in the form of a dry powder or spray dried and then subjected to a calcination treatment or a small amount of water and a binder may be added to the raw material mixture before calcination or the mixture of raw materials may be pressed with a ceramic, Is formed by a conventional method.

The firing treatment is carried out by maintaining the mixture at 700 to 1300 占 폚 for a suitable time (for example, 0.5 to 5 hours).

In the calcination process of the raw material powder mixture, the alkali metal compound acts as a flux upon melting, and TiO ₂ reacts with RO when molten (alkaline earth metal titanate (RTiO ₃ ) formation reaction). In addition, the M ₂ O of the mixture reacts with TiO ₂ to form an alkali metal titanate (M ₂ Ti _n O _{2n + 1} ). Therefore, unlike the conventional flux process for producing an inorganic compound, it is not necessary to remove the flux from the reaction mixture, and the alkali metal component present in the raw material is used without any waste in the production of the composite titanium compound powder.

In the production process of the present invention, the alkali metal compound acts as a flux to form a fine alkaline earth metal crystal at a relatively low temperature. In addition, the presence of an alkaline earth metal compound or the formation of an alkaline earth metal titanate interferes with the growth of conventional needle crystals of an alkali metal titanate to form rather tubular crystals . Thus, very fine crystals are collected into particles in the form of fine lumps that are measured in the size of tens of microns. When the raw material mixture is in the form of a spray-dried particle with an appropriate size (for example, 10 to 100 mu m), and when subjected to a calcination treatment, the obtained particles are generally spherical (see Fig. 1).

The raw material powder mixture has an arbitrary ratio between the numbers of moles of X and Y. [ The molar ratio of X to Y of the alkaline titanium titanate (RTiO ₃ ) to the alkali metal titanate (M ₂ Ti _n O _{2n + 1} ) of the powder obtained by the calcination treatment corresponds to X / Y of the raw material mixture do.

When the composition ratio of the raw material mixture is adjusted to Z = X + mY, the powder particles obtained by the calcination treatment are composed of two kinds of crystals, namely, an alkaline earth metal titanate (RTiO ₃ ) and an alkali metal titanate (M ₂ Ti _n O _{2n +} Lt; / RTI > When the ratio is adjusted to Z > X + 6Y, the obtained powder particle contains a titanium dioxide (TiO ₂ ) crystal as a third phase in addition to the two kinds of crystals (amount corresponding to Z- (X + 6Y) Number of moles)), these three kinds of crystals are mixed with each other.

Since the reaction of forming an alkaline earth metal titanate (RTiO ₃ ) does not occur at a low temperature, the firing treatment temperature is at least 700 ° C, and the preferable treatment temperature is at least 800 ° C or more. The upper limit of the treatment temperature should be 1300 占 폚 to avoid melting of the formed alkali metal titanate crystals, and the upper limit is preferably 1200 占 폚.

Fig. 1 and Fig. 2 show a fine lumpy body in which very fine crystals of calcium titanate (alkaline earth titanate) and very fine crystals of potassium hexatitanate (alkali metal titanate) are mixed together and the particles are Z = X + 6Y Z, X and Y are positive numbers). In these photographs, the large tubular crystal is potassium 6-titanate and the small crystal is calcium titanate.

3 is an electron micrograph of a single phase of calcium titanate produced in the same manner as in Fig. 1 when Z = X + mY (where Y is 0). The crystals of the particles are generally cubic, and the calcium titanate has a size at least several times the size of the crystal of Fig.

Fig. 4 is an electron micrograph of a particle consisting of a single phase of potassium 6-titanate produced in the same manner as in Fig. 1 when Z = X + mY (where X is 0 and m is 6) Unlike FIG. 1, it is in the form of a fine needle-like fiber.

[Examples of Composite Titanium Compound Powder]

Next, specific examples of the composite titanium compound powder according to the present invention will be described.

As the TiO ₂ or the titanate, refined tin powder is used, and as the alkaline earth metal compound, potassium carbonate, barium carbonate, strontium carbonate or magnesium carbonate are used.

The raw material compounds in powder form are appropriately mixed and an appropriate amount of water (corresponding to twice the blending amount of the powder) is added to this mixture to prepare a slurry and spray-dried to give particles (average particle size 40 μm).

The dry particle mixture was charged into an alumina crucible and calcined in an electric furnace (calcination treatment temperature: see Table 1, calcination treatment time: 1 hour) to obtain a titanium compound powder (particle size 10 to 100 탆, average particle size 33 탆) .

Table 1 shows the ratio of the starting compound powder and the crystal composition of the obtained powder. Each raw material compound is in a form of heating.

[Table 1]

According to Nos. 1 to 4 of Table 1, the ratio of the starting compound powder is adjusted by Z = X + 6Y (where Z is the number of moles of TiO ₂ , X is the number of moles of CaO, and Y is the number of moles of K ₂ O) And the obtained powder is composed of titanium compound particles in which calcium titanate (CaTiO ₃ ) crystals are mixed with potassium hexatitanate (K ₂ Ti ₆ O ₁₃ ) crystals. The ratio (molar ratio) of calcium titanate to potassium 6-titanate corresponds to the molar ratio of CaO to K ₂ O (X / Y) in the raw powder mixture.

According to No. 5, the ratio of the starting compound powder is adjusted to Z = X + 6Y (where Z is the number of moles of TiO ₂ , X is the number of moles of BaO, and Y is the number of moles of K ₂ O) The barium titanate (BaTiO ₃ ) crystal is composed of composite titanium compound particles mixed with potassium hexatitanate (K ₂ Ti ₆ O ₁₃ ) crystals. The ratio (molar ratio) of barium titanate to potassium 6-titanate corresponds to the molar ratio (X / Y) of BaO to K ₂ O in the raw powder mixture.

According to No. 6, the ratio of the starting compound powder is adjusted to Z = X + 6Y (where Z is the number of moles of TiO ₂ , X is the number of moles of SrO, and Y is the number of moles of K ₂ O) Strontium titanate (SrTiO ₃ ) crystal is composed of composite titanium compound particles mixed with potassium hexatitanate (K ₂ Ti ₆ O ₁₂ ) crystals. The ratio (molar ratio) of strontium titanate to potassium 6-titanate corresponds to the molar ratio of SrO to K ₂ O (X / Y) in the raw powder mixture.

According to No. 7, the ratio of the raw material powder is Z = X + 6Y (where Z is the number of moles of TiO ₂ , X

The number of moles of MgO, and Y is the number of moles of K ₂ O), and the resulting powder is composed of composite titanium compound particles in which magnesium titanate (MgTiO ₃ ) crystals are mixed with potassium hexatitanate (K ₂ Ti ₆ O ₁₃ ) crystals have. The ratio (molar ratio) of magnesium titanate to potassium 6-titanate corresponds to the molar ratio (X / Y) of MgO to K ₂ O in the raw powder mixture.

According to No. 8, the ratio of the starting compound powder is adjusted to Z = X + 4Y (where Z is the number of moles of TiO ₂ , X is the number of moles of CaO, and Y is the number of moles of K ₂ O) The calcium titanate (CaTiO ₃ ) crystal is composed of composite titanium compound particles mixed with potassium tetratitanate (K ₂ Ti ₄ O ₉ ) crystals. The ratio (molar ratio) of calcium titanate to potassium 4-titanate corresponds to the molar ratio of CaO to K ₂ O (X / Y) in the raw powder mixture.

According to No. 9, the ratio of the raw material powder is Z = X + 3Y wherein Z is the number of moles of TiO ₂ , X

Is the number of moles of CaO, and Y is the number of moles of Na ₂ O), and the obtained powder is a composite titanium compound particle in which calcium titanate (CaTiO ₃ ) crystal is mixed with ₃ trisodium carbonate (Na ₂ Ti ₆ O ₇ ) consist of. The quantity ratio of the calcium titanate to 3. Tea sodium carbonate (mole ratio) corresponds to a molar ratio of Ca0 (X / Y) vs. Na ₂ O in the raw material powder mixture.

According to No. 10, the ratio of the starting compound powder is adjusted to Z = X + 5.5Y (where Z is the number of moles of TiO ₂ , X is the number of moles of CaO, and Y is the number of moles of K ₂ O) The powder is composed of calcium titanate (CaTiO ₃ ) crystal, potassium 6-titanate (K ₂ Ti ₆ O ₁₃ ) crystal and potassium 4-titanate (K ₂ Ti ₄ O ₉ ) crystal, Compound particles. The ratio (molar ratio) of K ₂ Ti ₆ O ₁₃ to K ₂ Ti ₄ O ₉ of these particles is 1/1, and the ratio (molar ratio) of the combined amounts of CaTiO ₃ to K ₂ Ti ₄ O _{9 of the} particles is Corresponds to the molar ratio (X / Y) of CaO to K ₂ O.

According to No. 11, the ratio of the starting compound powder is adjusted to Z> X + 6Y (where Z is the number of moles of TiO ₂ , X is the number of moles of CaO, and Y is the number of moles of K ₂ O) And calcium titanate (CaTiO ₃ ) crystals are composed of composite titanium compound particles in which potassium hexatitanate (K ₂ Ti ₆ O ₁₃ ) crystals and titanium dioxide (TiO ₂ ) crystals are mixed with each other. The ratio (molar ratio) of CaTiO ₃ to K ₂ Ti ₆ O ₁₃ of the particles corresponds to the molar ratio (X / Y) of CaO to K ₂ O of the raw powder mixture. The amount (molar ratio) of titanium oxide formed corresponds to the difference between Z and (X + 6Y).

(RTiO ₃ (where R is an alkaline earth metal) and an alkali metal titanate (M ₂ Ti _n O _{2 n} ( _{where n} is an integer of _{1 or more} ) by adjusting the ratio of TiO ₂ , RO and M ₂ O contained in the raw material powder mixture, _+1; wherein, M is the ratio, or the alkali metal titanate (M ₂ Ti _n O _{2n + l)} of a kind, or two children and the ratio such as the other composite titanium compound powder of titanium oxide (TiO ₂₎ of an alkali metal) Can be obtained.

Formation of friction material

Hereinafter, the friction material of the present invention will be described.

The friction material is formed by mixing the base powder and at least the binder resin and molding the mixture. The base powder to be used is represented by a crystal of an alkaline earth metal titanate represented by RTiO ₃ (wherein R is an alkaline earth metal) and M ₂ Ti _n O _{2n + 1} (wherein M is an alkali metal and n is an integer of 2 to 6) , Or a composite titanium compound particle composed of these two types of crystals and a titanium dioxide (TiO ₂ ) crystal.

The titanium compound powder used as the base material is composed of a predetermined proportion of the crystalline phase. However, in a powder of a two-phase structure composed of an alkaline earth titanate (RTiO ₃ ) and an alkali metal titanate (M ₂ Ti _n O _{2n + 1} ), the molar ratio of RTiO ₃ / M ₂ Ti _n O _{2n +} 40) / 1 and that the molar ratio of RTiO ₃ / M ₂ Ti _n O _{2n + 1} / TiO ₂ is in the range of (0.2 to ₂₀ ) / (TiO ₂ ) in the powder of the three phase structure composed of titanium dioxide (TiO ₂ ) 40) / 1 / (0.1 to 20).

Suitably, the proportion of the composite titanium compound powder is about 3 to 50% by weight based on the total friction material. If the ratio is less than 3% by weight, the powder can not sufficiently exhibit the predetermined effect, whereas if it exceeds 50% by weight, the effect of improving the abrasion resistance can not be improved.

Other known materials may be used in combination with the composite titanium compound powder as the base material for the friction material of the present invention. Examples of such materials include polyamide (nylon) fibers, aramid fibers, acrylic fibers, steel fibers, stainless steel fibers, copper fibers, brass fibers, carbon fibers, glass fibers, alumina- And at least one or more of these materials may be selected and used as desired. These known base materials are not particularly limited and may be used in a proportion of 10 to 65% by weight, based on the blending amount of the substance and the titanium compound powder.

In order to improve dispersibility and bondability to the binder resin as required, the base material may be mixed with a silane coupling agent (aminosilane, vinylsilane, epoxy silane, methacryloxy silane or mercaptooxy silane Or the like) or a titanate-based coupling agent (such as isopropyltriisostearoyl titanate or di- (dioctylpyrophosphate) ethylene titanate).

When it is necessary to improve the frictional wear characteristics (such as friction coefficient, abrasion resistance, vibration characteristics, and noise), the friction material of the present invention may be coated with, for example, vulcanized or unvulcanized natural or synthetic rubber powder, Inorganic powders such as natural or artificial graphite, mica, molybdenum disulfide, antimony trioxide, barium sulfate and calcium carbonate powder, metal powders such as copper, aluminum, zinc and iron powder, alumina, silica, (For example, 20 to 70% by weight) of at least one known friction and wear control agent selected from oxide powders such as zirconium oxide, chromium oxide, copper oxide, antimony trioxide and titanium dioxide titanium dioxide powder.

(For example, up to 50% by weight) of various additives such as a corrosion inhibitor, a lubricant, and a wearer are added to the friction material of the present invention, depending on the application and use conditions.

Examples of the binder resin include thermosetting resins such as phenol resin, formaldehyde resin, epoxy resin and silicone resin, modified (cashew oil modified or dry modified) thermosetting resin produced from these resins, natural rubber, styrene-butadiene rubber, And the like are usually used.

The mixture for producing the friction material of the present invention is produced in the same manner as the conventional friction material except that the composite titanium compound powder is used as the base material. There are no special conditions or limitations on the manufacturing process of the friction material.

More specifically, the base material is dispersed in a binder resin, and if necessary, a friction / wear modifier, a corrosion inhibitor, a lubricant, an abrasive or the like is added to the dispersion, and these components are uniformly mixed into the composition. The composition is formed into a predetermined shape in advance, if necessary, and is molded under a heating and pressing (pressure: about 10 to 40 MPa, temperature: about 150 to 200 캜) by a die or the like. After the molded body is squeezed from the die, the body is subjected to heat treatment (temperature: about 150 to 200 캜, holding time: about 1 to 12 hours) as required in a furnace, and then subjected to work polishing and finishing to obtain a friction material having a predetermined shape. Alternatively, as another method, the composition is dispersed in water or the like, the composition is formed into a sheet by using a screen, the sheet is dewatered, an appropriate number of sheets are stacked, the assembly is molded under heat and pressure, There is also a certain friction material.

The titanate alkaline earth metal RTiO ₃ (where R is Mg, Ca, Sr, Ba, etc.) is a compound having a perovskite crystal structure and is excellent in stress, heat resistance, abrasion resistance or abrasion resistance, I have. The friction material of the present invention is characterized in that the perovskite-type alkaline earth titanate crystal has a layered or tunnel-like structure represented by M ₂ Ti _n O _{2n + 1} (wherein M is an alkali metal and n is 2 to 6) And a substrate formed of a two-phase titanium compound powder mixed with an alkali metal titanate crystal. Alternatively, the base material of the friction material is formed of a three-phase titanium compound powder in which titanium dioxide (TiO ₂ ) crystals are mixed with these two kinds of crystals. The friction material of the present invention has a higher coefficient of friction than an alkali metal titanate, that is, a single-phase compound, which acts as a base material, and maintains a high coefficient of friction over a wide temperature range.

[Embodiment of friction material]

Hereinafter, specific examples of the friction material of the present invention will be described.

Preparation of raw material composition

Table 2 shows the composition forming the friction material. In Table 2, Nos. 21 to 24 are examples of the present invention, and Nos. 25 to 28 are comparative examples. The symbols A 1 to A 4, B 1, B 2 and C used in the "titanium compound" and the base materials of No. 21 to No. 28 are as follows.

A ₁ : CaTiO ₃ / K ₂ Ti ₆ O ₁₃ = 2 mol / mol

Particle size: 10 to 100 탆 (titanium compound of the product No. 2 in Table 1)

A ₂ : CaTiO ₃ / K ₂ Ti ₆ O ₁₃ = 10 mol / 1 mol

Particle size: 10 to 100 탆 (titanium compound of the product No. 3 in Table 1)

A ₃ : CaTiO ₃ / K ₂ Ti ₆ O ₁₃ = 10 mol / mol

Particle size: 10 to 100 탆 (titanium compound of the product No. 4 in Table 1)

A ₄ : CaTiO ₃ / K ₂ Ti ₆ O ₁₃ / TiO ₂ = 4 mol / 1 mol / 1 mol

Particle size: 10 to 100 탆 (titanium compound of the product of No. 11 in Table 1)

B ₁ : 6 spherical particles of potassium titanate (K ₂ Ti ₆ O ₁₃ ) single phase

Particle size: 10 ~ 100㎛

B ₂ : 6 Potassium titanate (K ₂ Ti ₆ O ₁₃ ) Single phase fiber

Fiber length: 150 탆 (average)

Fiber diameter: 30 탆 (average)

C: Powder of single phase of calcium titanate (CaTiO ₃ )

Particle size: 1 ~ 5㎛

Class 6 crytile asbestos fibers are used in No. 28.

Molding of the composition

(Pressure: 14.7 MPa = 150 kg / cm < 2 >, temperature: 170 DEG C) was prepared in a predetermined shape (pressure of 14.7 MPa , Pressure holding time: 5 minutes). The molded body is taken out from the die and heat-treated in a drying furnace (180 DEG C, 3 hours). Next, the molded body is cut to a predetermined size and polished to obtain a friction material sample (disk pad).

Friction test

The friction material sample is subjected to a friction test according to " JASO (Japan Automobile Standard Association) C 406, Dynamometer test method for passenger car brake device ". Measure the friction coefficient and wear of the other rotor. Table 2 shows these results.

The coefficient of friction shown in Table 2 is the data obtained by the second effect test under the braking initial velocity state of 50 km / h and 100 km / h and the 0.6 G deceleration.

[Table 2]

As a result of the tests shown in Table 1, the friction materials (No.21 to No.24), which are embodiments of the present invention, exhibited a higher friction coefficient than the friction materials (No. 25 and No. 26) using a 6-potassium titanate (alkali metal titanate) Has a high coefficient of friction over a range from a relatively low initial braking speed to a high initial braking speed which significantly increases the temperature of the surface. The material of the present invention reduces abrasion of the rotor, so that the abrasion resistance of the other is reduced.

The friction material (No. 27) made of a single-phase calcium calcium titanate (alkaline earth metal titanate) has a problem of abrasion resistance of the counterpart even though it has a high friction coefficient.

The friction material (No. 28) using the asbestos base material is inferior to the present invention in terms of friction coefficient and counterpart aggressiveness.

The friction material of the present invention has a high coefficient of friction and nevertheless reduces the polishing abilities of the counterpart since the extremely fine crystals of the alkaline earth titanate and the alkali metal titanate are uniformly dispersed in the material. The effect of uniformly dispersing such fine crystals can not be obtained by simply mixing an alkaline earth metal titanate powder and an alkali metal titanate powder prepared by a conventional method with each other.

The composite titanium compound powder according to the present invention has properties of each compound because it is composed of an alkaline earth metal titanate crystal and an alkali metal titanate crystal or a mixture of these crystals and titania crystal as described above. For example, when used as a base material for a friction material for a braking device, the powder gives the material a high coefficient of friction and reduced abrasion resistance.

Further, according to the present invention, the composite titanium compound powder can be obtained by a simple method of heating the raw material powder mixture. In this production method, the alkali metal compound fraction acts as a flux of the titanic acid alkaline earth metal forming reaction and is consumed as a reactant for forming an alkali metal titanate. Therefore, unlike the ordinary flux process for producing an inorganic compound, There is no need to remove it. This simplifies the process and makes it possible to obtain a desired product, that is, a composite titanium compound powder, in high yield.

Claims (10)

RO and an alkaline earth metal compound to RO by (wherein, R is an alkaline earth metal) or heated, M ₂ O an alkali metal compound to the M ₂ O by (wherein, M is an alkali metal) or by heating and, TiO ₂ or the heat the titanium compound in TiO ₂ by, Z = X + mY (end, Z is a molar number, X is a number of moles, Y of the RO of TiO ₂ is the number of moles of m ₂ O, Z, X and Y are each a positive number, m Is 2 to 6) The blended mixture is prepared by calcining at 700 to 1300 占 폚, Characterized in that it is a fine lump shape in which crystals of an alkaline earth metal titanate expressed by RTiO ₃ and crystals of an alkali metal titanate represented by M ₂ Ti _n O _{2n + 1} (where n is an integer of 2 to 6) Composite titanium compound particles. The composite titanium compound according to claim 1, wherein R is an alkaline earth metal selected from the group consisting of Ca, Ba, Sr and Mg, and M is an alkali metal selected from the group consisting of Li, Na, K and Rb particle. RO and an alkaline earth metal compound to RO by (wherein, R is an alkaline earth metal) or heated, M ₂ O an alkali metal compound to the M ₂ O by (wherein, M is an alkali metal) or by heating and, TiO ₂ or the heat the titanium compound in TiO ₂ by, Z> X + 6Y (end, Z is a molar number, X is a number of moles, Y of the RO of TiO ₂ is the number of moles of M ₂ O, Z, X and Y are each a positive number) is By weight, The blended mixture is prepared by calcining at 700 to 1300 占 폚, A crystal of an alkaline earth metal titanate expressed by RTiO ₃ and a crystal of an alkali metal titanate represented by M ₂ Ti _n O _{2n + 1} (where n is an integer of 2 to 6) and a titanium dioxide (TiO ₂ ) crystal Wherein the composite titanium compound particles are in the form of a mixed fine particle. The composite titanium compound according to claim 3, wherein R is an alkaline earth metal selected from the group consisting of Ca, Ba, Sr and Mg, and M is an alkali metal selected from the group consisting of Li, Na, K and Rb particle. A crystal of an alkaline earth metal titanate represented by RTiO ₃ (wherein R is an alkaline earth metal) and an alkali metal titanate alkali metal oxide represented by M ₂ Ti _n O _{2n + 1} (wherein M is an alkali metal and n is an integer of 2 to 6) (R is an alkaline earth metal) or an alkaline earth metal compound which is made into RO by heating, and M ₂ O (wherein, in the formula, R 2 is an alkaline earth metal) M is a mixture of the titanium compound in TiO ₂ by an alkali metal compound and, TiO ₂ or the heating of a M ₂ O by an alkali metal) or heating, Z = X + mY (However, Z is the number of moles of TiO _2, X is the number of moles of RO, Y is the number of moles of M ₂ O, and Z, X and Y are each a positive number and m is 2 to 6), and the step of calcining the mixture at 700 to 1300 ° C ≪ / RTI > by weight of the composite titanium compound powder. A crystal of an alkaline earth metal titanate represented by RTiO ₃ (wherein R is an alkaline earth metal) and an alkali metal titanate alkali metal oxide represented by M ₂ Ti _n O _{2n + 1} (wherein M is an alkali metal and n is an integer of 2 to 6) A method for producing a composite titanium compound powder comprising particles of a fine lumpy body in which crystals and titanium dioxide (TiO ₂ ) crystals are mixed, characterized in that an RO (wherein R is an alkaline earth metal) A mixture of a metal compound and an alkali metal compound which is M ₂ O (M is an alkali metal) or M ₂ O by heating and a titanium compound which is TiO ₂ by heating or TiO ₂ is changed to Z> X + 6Y ( Wherein Z is the number of moles of TiO ₂ , X is the number of moles of RO, Y is the number of moles of M ₂ O, and Z, X and Y are each a positive number) and a step of calcining the mixture at 700 to 1300 ° C. And a step of treating the composite titanium compound powder. A crystal of a titanium alkaline earth metal expressed by RTiO ₃ (wherein R is an alkaline earth metal) and an alkali metal titanate (expressed by M ₂ Ti _n O _{2n + 1} wherein M is an alkali metal and n is an integer of 2 to 6) By weight of a composite titanium compound powder and at least a binder resin. An alkaline earth metal titanate crystal represented by RTiO ₃ (wherein R is an alkaline earth metal) and an alkali metal titanate alkali metal oxide represented by M ₂ Ti _n O _{2n + 1} (wherein M is an alkali metal and n is an integer of 2 to 6) And a composite titanium compound powder composed of a titanium dioxide (TiO ₂ ) crystal and at least a binder resin. The friction material according to claim 7, wherein the friction material contains 3 to 50% by weight of the composite titanium compound powder. The friction material according to claim 8, wherein the friction material contains 3 to 50% by weight of the composite titanium compound powder.