WO1997009471A1 - Surface-coated whisker - Google Patents

Abstract

A surface-coated whisker having an increased specific surface area, an excellent dispersibility in matrices such as synthetic resins, and a high reinforcement effect. It is produced by coating the surface of a whisker with at least one member selected among superfine particles of metal oxides and hydroxides with particle diameters of the order of nanometer or below.

Description

 Specification

 Surface-coated whiskers

 Technical field

 The present invention relates to a surface-coated whisker.

 The surface-coated whiskers of the present invention have an increased specific surface area compared to untreated whiskers, have excellent dispersibility in a matrix of synthetic resin or the like, and have a high reinforcing effect. It also has very favorable properties.

 In addition, among the surface-coated whiskers of the present invention, those coated with ultrafine particles of a metal oxide or metal hydroxide other than titanium dioxide have good weather resistance and ultraviolet light. It has excellent properties that it is not easily decomposed even when irradiated.

 The surface-coated calcium whisker of the surface-coated whiskers of the present invention has a characteristic of not releasing potassium in addition to the above-mentioned preferable characteristics.

 Background technology

Titanium phosphate alkali metal U i Ska one has the general formula _{Μ 2 0 · m T i O} 2 · n H 2 O ( wherein, M is shows the alkali metal, m a 1 to 1 0 integer And n represents 0 or an integer of 1 to 10. The composition has a composition represented by the following formula, and a fiber diameter of 0.1 to 0.1.

1. A whisker with a length of about Ομπι and a fiber length of about 5 to 50111. Specifically, potassium titanate whiskers and whiskers Known are sodium titanate whiskers, lithium titanate whiskers, etc. Among these, potassium titanate whiskers are widely used.

The titanic acid disc is mainly used as a reinforcing material such as a synthetic resin and a paint, and as a material for an engine oil letter for an engine. The synthetic resin containing the whiskers is widely used, for example, by being molded into brake pads for passenger cars, keyboard parts for 0A equipment, gears for watches, and the like. The titanium whisker has excellent properties in various applications, and there is still room for improvement. For example, the dispersibility in a synthetic resin is rather poor, and it is difficult to increase the amount of addition, so that the reinforcing effect tends to be insufficient. In addition, since potassium titanate whiskers release calcium, they are used as reinforcing materials for synthetic resins that are easily decomposed by a power rim such as a polycarbonate resin. To use it, it is general to apply a surface treatment with a silane coupling agent or the like, but it is still impossible to avoid elution of calcium. Further, the synthetic resin containing titanium Nsanka Li Umuu I scar and the exposed to ultraviolet light, are decomposed該U T i 0 ₂ Lee in Scar to release active oxygen, oxygen this is such as a synthetic resin It may oxidize and degrade the matrix.

On the other hand, conductivity is imparted to the potassium titanate whiskers. For this reason, the surface has been conventionally coated with a conductive material such as a conductive metal or a carbonaceous material. For example, Japanese Examined Patent Publication No. 5-222648 states that tin, indium, antimony, niobium, tin, indium, antimony, and niobium have been added to aqueous slurries of already manufactured potassium titanate whiskers. A method is disclosed in which an aqueous solution of a metal compound containing a conductive metal such as tungsten or molybdenum is added, and insolubles are removed by filtration and then heat-treated to produce a conductive disk. A method of adding an acid at the same time is also known (Japanese Patent Publication No. 7-23221). However, the conductive whiskers obtained by these methods have a large specific surface area, for example, because the metal oxide particles attached to the surface have a size exceeding nm units. No increase is observed.

Furthermore, Japanese Patent Application Laid-Open No. 2-221460 discloses a potassium hexatitanate whisker whose surface is coated with titanium dioxide. This is achieved by (a) mixing a titanium compound and a potassium compound, and baking the mixture at 900 to 1200 ° C. to form an aggregate of temporary fibers. The slurry was defibrated to obtain a slurry, the pH of the slurry was adjusted to 9.3 to 9.7, and further adjusted to pH 8.0 to 9.1. 0 or more (or mouth) to the aqueous slurry of the already manufactured potassium whisker -

(In this example, the pH of the slurry was adjusted).

Adjusted to 6.0), and a titanium hydrated oxide is adhered to the surface of the potassium hexatitanate whiskers, and then heated again to 600 ° C or higher. However,

 In the potassium hexatitanate whisker obtained by the method (a), titanium dioxide is not uniformly adhered to the surface. In addition, in the case of the potassium hexatitanate whiskers according to the method of (Mouth), since the titanium dioxide adhering to the surface is of an anatase type, it is inevitable that the reinforcing effect is reduced. Further, in any of the methods (a) and (mouth), the obtained surface-coated potassium hexatitanate whisker has a titanium dioxide particle size adhered to the surface in the order of nm. Therefore, no remarkable increase in the specific surface area is observed.

 In addition, these prior arts do not suggest a method of adding a water-soluble metal salt and performing a neutralization operation in the process of manufacturing potassium titanate whisker itself.

 Disclosure of the invention

The present inventor has conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, when producing potassium titanate whiskers, a specific metal compound was added to the aqueous slurry of the temporary fiber. By adding and neutralizing, the specific surface area (BET specific surface area, hereinafter the same) increases as compared with untreated whiskers, and the Extremely favorable properties, such as excellent dispersibility, good weather resistance, hardly decomposed even when irradiated with ultraviolet rays, remarkably little elution of force rim, and high reinforcing effect The same treatment is applied to the surface-coated potassium titanate whiskers having the above-mentioned properties, and to other inorganic whiskers that can be produced in the same manner as the potassium titanate whiskers. It has been found that similar remarkable effects can be obtained by applying. The present invention has been completed based on such findings.

 According to the present invention, the surface of the whisker is coated with at least one selected from ultrafine particles of a metal oxide and ultrafine particles of a metal hydroxide having a size of nm units or less. O Surface-coated whiskers are provided.

 The surface-coated whisker of the present invention has the following remarkable effects as compared with untreated whiskers.

 (1) Due to its large specific surface area, for example, an oil filter manufactured using the same can significantly improve the filtration characteristics and significantly contribute to prolonging the oil life.

(2) Good dispersibility in the synthetic resin matrix Therefore, the filling amount of the synthetic resin can be increased, and a higher reinforcing effect can be exhibited.

 (3) The properties of the surface-coated whiskers obtained depending on the metal species of the metal oxide or metal hydroxide to be coated are somewhat different.For example, the specific surface area when copper oxide is coated The increase in water absorption is not appreciably recognized, but the water absorption is significantly reduced, and a surface-coated disc useful as a filler for a brake material can be obtained.

 Further, of the surface-coated whiskers of the present invention, the surface-coated potassium titanate whiskers have the following characteristics in addition to the above-mentioned preferable characteristics.

 (4) Those coated with ultrafine particles of metal oxides other than titanium dioxide and Z or metal hydroxide have improved weather resistance and release a large amount of active oxygen even when irradiated with ultraviolet rays. And does not cause oxidation of the matrix and subsequent deterioration.

 (5) The amount of eluted calcium is remarkably smaller than that of common potassium titanate whiskers.

Based on these effects, the surface-coated whiskers of the present invention can remarkably improve the reinforcing effect on a matrix such as a synthetic resin, and can maintain the reinforcing effect for a long period of time. it can. The reason why these effects are achieved is not fully understood. Due to the force of the present invention, ultrafine metal oxide particles and / or metal having a size of nm or less on the surface of the whisker by the treatment of the present invention. This is considered to be due to the uniform attachment of the hydroxide particles. It is considered that the improvement in dispersibility is due to the change in the potential of the surface of the disc due to the attachment of the ultrafine particles.

 The surface-coated whisker of the present invention has at least one kind selected from ultrafine particles of a metal oxide and ultrafine particles of a metal hydroxide having a surface of a nanometer or smaller. Preferably, it is coated with ultrafine particles of a metal oxide.

 Usually, in the case of a steel sheet whose surface is coated with a metal oxide or the like by a conventional method, the copper sheet is examined with a transmission electron microscope (magnification: about 50,000 times). When observed, particles such as metal oxides are observed on the surface. These particles are larger than nm units by magnification. However, even when the surface-coated whiskers of the present invention are observed at the same magnification, there are almost no irregularities on the surface, and no particulate matter is observed on the surface.

The following points can be cited as evidence that the surface of the surface-coated disk of the present invention is coated with a metal oxide or the like. First, the results of elemental analysis such as X-ray fluorescence analysis are given. X-ray fluorescence analysis confirms the presence of a metal oxide that is separate from the components of the whiskers.

 The surface-coated whisker of the present invention has an increased specific surface area as compared to the whisker before coating.

 Furthermore, the surface coating whisker of the present invention has at least one inflection point when the correlation between its zeta potential (electrokinetic potential) and pH is shown in a line graph. I have. Despite the fact that the uncoated surface of titanium carbide whiskers do not have inflection points, the surface coating whiskers have inflection points.裏 と 表面 表面 表面 表面 表面 表面 と と と と と 表面 表面 と と と と と. The surface of the metal oxide having an inflection point and a metal oxide or a metal hydroxide supports the surface uniformly.

 From the above evidence, it is clear that the surface-coated whisker of the present invention has its surface uniformly coated with a metal oxide and / or a metal hydroxide. On the other hand, almost no particle shape is observed even at about 50,000 times with a transmission electron microscope, so that the surface metal oxides and / or metal hydroxides are in nm units or less. It is inferred that they are ultrafine particles of the size

Among surface-coated window Lee Scar of the present invention, ultrafine particles of metal oxides, in particular _{A 1 2 0 3, F e} 2 0 3, Z r 0 2, C u O And those had it occurred coated ultrafine particles S i 0 few selected Ri by ₂ made from a group rather with one of metallic oxides have a good RiRyo favorable properties.

 The surface-coated whisker of the present invention is manufactured in the same manner as the conventional whisker manufacturing except that a water-soluble metal salt or an aqueous solution thereof is added at a specific stage of the conventional whisker manufacturing process. it can.

 Conventional whiskers include potassium titanate whiskers and inorganic whiskers that can be produced in the same manner as the potassium titanate whiskers.

As a method for producing potassium titanate whiskers, there are many known methods for producing the titanium whiskers. In the present invention, a conventionally known production method in which a neutralization step can be set during the production step The law is widely available. Specifically, for example, firing method, melting method, hydrothermal method, flux method, slow cooling firing method, etc. (Handbook using new functional fibers, Industrial Research Institute, Inc. Among them, firing method, melting method, flux method, slow cooling firing method, etc. are preferred. More specifically, for example, a slurry obtained by heating a mixture of raw material compounds for whiskers or a melt (all of which are aggregates of temporary fibers) is defibrated in water to obtain a slurry. The pH is adjusted (neutralized) by adding acid or alcohol to the slurry. This is a method in which a solid content is collected by filtration, and the solid content is dried and heated (fired) to obtain a discer.

Examples of inorganic discs other than potassium titanate whiskers include sodium titanate whiskers, canola silicate whiskers, and phosphoric acid whiskers. Aluminum whisker whiskers, magnesium borate wisdom, zinc silicate whiskers, basic magnesium sulphate whiskers, magnesium oxide wisdom And scars and silicon carbide whiskers. Of these, potassium titanate whiskers, sodium titanate wisdom, silicate cane silicate wisker, aluminum borate wisdom Carbide, magnesium borate and magnesium whiskers are preferred, and potassium titanate whiskers and sodium titanate whiskers are preferred. Particularly preferred ₍ as described above, the surface-coated whisker of the present invention is preferably used in a general method for producing a whisker including a neutralization step, before the water-soluble metal salt or a salt thereof before the neutralization step). It can be manufactured by adding an aqueous solution.

More specifically, a slurry obtained by heating a mixture of compound materials for the production of iskers, and sintering the aggregate of temporary fibers, such as a sintered body and a melt, in water to obtain a slurry obtained It can be produced by adding a water-soluble metal salt or an aqueous solution thereof to the mixture, followed by neutralization, filtration, drying, and heating (calcination) according to a usual method. Since the temporary fibers are monodispersed at the time of defibration, it is considered that the surface of the temporary fibers is covered with the metal salt very uniformly.o

 According to this method, it is possible to easily control the specific surface area of the obtained surface-treated whisker by appropriately changing the amount and type of the water-soluble metal salt. The whiskers themselves are less damaged, and the object can be obtained much more easily and inexpensively than conventional conductive metal coating on whiskers.

 There is no particular limitation on the water-soluble metal salt, and those which can form a known hydroxide which can be used regardless of conductivity or non-conductivity are preferred. Specifically, for example, excluding alkaline metals (Na, K, etc.), alkaline earth metals (Mg, Ca, Sr, Ba, etc.), alkaline metals and alkaline earth metals The 4th Periodic Elements excluding the 3rd Periodic Elements of the Periodic Table (Al, Si, etc.), alkaline metals and alkaline earth metals

(Ti, Fe, Co, Ni, Cu, Zn, etc.), 5th periodic element of the periodic table (Zr, Sn, Mo) excluding alkaline metals and alkaline earth metals Water-soluble salts containing at least one kind of metal such as a halide, an oxide, a nitrate, a sulfide, a sulfate, and a water-soluble salt. Oxides and the like can be mentioned. More specifically, for example, A 1 C 1 _3, and _{C o C l 2, Z r} C, S n C l 2,

_{S n C 1 4, T i} CI 3, T i C ] _4, F e C 1 _2,

_{F e C l 3, C u} C l 2, N i C l 2, M o C ",

_{M g C l 2, C a} C l 2, S r C l 2, B a C l Shioi匕of such _2, "(3 0 _{4) 3,} (: 0 3 0 _4, (: 1 3 0 ₄ ,

F e S 0 ₄ sulfates such _{as, N a 4 S i 0 4} , K 2 S i 4 0 9 like silicate product of can and this include the _{Z r C 1 2 0, N} a A 1 0 2 , etc. among _{them, a 1 C 1 3, N} a a 1 0 2,

_{F e C l 2, F e} C l 3, C u C l Z r C l 2 O,

N a ₄ S i 0 ₄ or the like is preferred arbitrariness. One type of water-soluble metal salt can be used alone, or two or more types can be used in combination. The amount of the water-soluble metal salt to be used can be appropriately selected from a wide range according to the purpose of the surface-coated whiskers to be obtained, the type and amount of the raw material for the whiskers, the heating (firing) temperature and time, etc. Normally, it is determined by the type of whisker and the amount of raw material used. It is about 0.01 to 100% by weight, preferably 0. It may be about 0 to 10% by weight. After adding the water-soluble metal salt or an aqueous solution thereof, neutralization, drying and baking are performed, whereby the metal oxide and / or metal hydroxide can be uniformly attached to the surface of the whisker.

The following is an example of a method of selecting a potassium titanate whisker as a whisker and applying a surface coating to the whisker. Will be described more specifically.

 First, the raw material compounds for whiskers are mixed. The raw material compounds for the production of potassium titanate whiskers are titanium compounds and magnesium compounds.

 Examples of the titanium compound include titanium dioxide such as an analog-type titanium dioxide and rutile-type titanium dioxide, and a titanium compound that generates titanium dioxide by firing. Wear. The titanium compound that produces titanium dioxide by firing is not particularly limited, and examples thereof include hydrous titanium oxide, rutile ore, titanium hydroxide, titanium chloride, and the like. . As the titanium compound, one type can be used alone, or two or more types can be used in combination.

 As the potassium compound, for example, there may be mentioned a dirt oxidizing sphere, a diluting lithium compound which generates a distilling lithium by firing, and the like. The potassium compound that produces potassium dioxide by firing is not particularly limited, and examples thereof include potassium hydroxide, potassium carbonate, and potassium nitrate. You. One of the calcium compounds may be used alone, or two or more of them may be used in combination.

The mixing ratio of the titanium emission compound and Ca Li um compounds Ru can be selected appropriately from particularly restricted to a wide range without, but T i 0 ₂ and K ₂ 0 or calcined to produce Ri by the T i 0 ₂ or baked formation Generate more The _two may be mixed so that the molar ratio (T i 0 ₂ / K 20) to K 20 is generally about 1 to 10, preferably about 2 to 6.

Then, the mixture of the titanium compound and the calcium compound is heated at about 900 to 110 for about 1 to 10 hours, whereby an aggregate of temporary fibers is generated. During the heating, e.g., KCI, KF, KB r, KI, K 2 SO 4,

Κ ₂ Μ ο 0 _4, Ru can also this to add a well-known hula-click scan, such as Κ ₃ Ρ 0 _4. After cooling, the obtained aggregate of temporary fibers is immersed in water and defibrated to form an aqueous slurry. The water at this time may be room temperature water, or may be hot or cold water. Before adding the water-soluble metal salt or an aqueous solution thereof, the aqueous slurry preferably has a ρ Η value in an alkaline range.

Subsequently, add a water-soluble metal salt or an aqueous solution thereof with stirring, if necessary, stir well, and neutralize (ρΗ adjustment) by adding an acid or alkali. Neutralization in the present invention is to adjust the added water-soluble metal salt to a ρ 得 る region where a hydroxide can be formed.At this time, the ρ な る value as a guide is about 6 to 8, Preferably around 7. The acid used for the adjustment of ρ Η is not particularly limited, but examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid, oxalic acid, nitric acid, and phosphoric acid, and acetic acid and the like. Organic acids and the like can be mentioned. The alkali is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, and sodium hydrogencarbonate. , Ammonia, and the like. When the pH value is in an acidic region, an by-product of anatase-type titanium dioxide increases, and the effect of the obtained whisker as a reinforcing material decreases, which is not preferable. On the other hand, if the pH value is in an alkaline range, metal oxides may dissolve and the coating efficiency may decrease, and lithium titanate remains unpreferably. .

 After adjusting the pH, the temporary fiber is filtered, dried, and fired. Drying is usually about 50 ~ 200 ° C, preferably 80 ~

 It is carried out at a temperature of about 150 ° C, and usually finishes in about 1 to 10 hours, preferably in about 2 to 5 hours. The calcination is usually performed at a temperature of about 300 to 800 ° C, preferably about 500 to 700 ° C, and usually for about 10 minutes to 2 hours. It takes about 20 to 60 minutes. The sintered body (a set of whiskers) obtained after firing is defibrated according to the usual method and dried as necessary to produce the target surface-coated whiskers. Is done.

The surface-coated whisker of the present invention obtained in this way has a size similar to that of a general whisker, and has a diameter. Many have a length of about 0.1 to 1.0 Om and a length of about 5 to 50 m, and many have a length of about 10 to 2 O / rn.

 The surface-coated whisker of the present invention can be used to further improve the dispersibility in the matrix, if necessary, in order to further improve the dispersibility in the matrix. Silano coupling agents, such as minopropinole triethoxysilane, aminaminopropinole triethoxysilane, and titanate couplings The surface-coated whiskers of the present invention may be added with water or an appropriate organic binder, usually 50; It may be used after granulating to an appropriate size of about zm to 5 mm.

 The surface-treated whisker according to the present invention has an uncoated surface or a surface-coated surface according to a conventional method, as long as the effect is not impaired. Inorganic fibers such as whisker, glass fiber, carbon fiber, rock wool fiber, etc., and powdered inorganic materials such as talc, calcium carbonate, titanium oxide, silica, etc. You can do it.

The surface-coated whisker of the present invention can be used in virtually all fields in which whiskers have been conventionally used. For example, thermoplastic resins, thermosetting resins, etc. It is very useful as a reinforcing material for various synthetic resins and metal materials. Book The synthetic resin containing the surface-treated whiskers of the present invention is used for sliding members such as brake pads, keyboard parts, OA equipment such as gears, gears and switches, electric and electronic equipment, and precision equipment. In addition to parts, various paints, adhesives, etc., it can also be used for applications such as building materials and medical parts materials. Moreover, the finale letter produced using the surface-coated whisker of the present invention exhibits excellent filtration characteristics.

 The surface-treated whisker of the present invention exhibits various characteristics depending on the type of the whisker itself, the type of metal oxide and / or metal hydroxide coated on the surface, and the like. The applications are also different. For example, when the zinc oxide is a titanium oxide zinc oxide, if the metal oxide is an aluminum oxide such as aluminum, the specific surface area is increased. It is useful as a lining material and as a finalizer material, and if the metal oxide is copper oxide, it is particularly useful as a brake pad material due to a decrease in water absorption, and it can be used as a metal oxide. If the material is zirconium oxide, the braking force is improved by stabilizing the coefficient of friction, and it is particularly useful as a brake pad material.

 BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a line graph showing the correlation between the zeta potential and PH of the surface-coated whiskers of the present invention. FIG. 2 is a transmission electron micrograph (magnification: about 50,000 times) of the surface-coated whisker of the present invention.

 BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples. In the following, “%” means “% by weight”.

Examples 1 to 7

 50 g of titanium dioxide powder and 25 g of potassium carbonate were mixed, and the mixture was reacted at 1000 ° C. for 4 hours. After cooling, the reaction product is unraveled in water, water-soluble metal salts are added at the addition amount (%) shown in Table 1, mixed, and then sulfuric acid or potassium hydroxide is added. The pH was adjusted (neutralized) to 7.0, and after stirring for 30 minutes, the pH was adjusted again to 7.0. The theoretical amount of potassium titanate whiskers in this example is 57 g. After the neutralization, the solid was collected by filtration, dried at 110 ° C. for 4 hours, and then calcined at 600 ° C. for 30 minutes to produce a potassium titanate whisker.

 The specific surface area of the obtained potassium titanate whiskers was measured. The equipment and measurement conditions used for measuring the specific surface area are as follows.

Specific surface area measuring device: Micromeritics GE INI 2360 manufactured by Shimadzu Corporation Pretreatment device: Micromeritics Flow Prep060, manufactured by Shimadzu Corporation

Specific surface area Pretreatment conditions: Pretreatment temperature 120 ° (: N ₂ gas purge: 60 minutes)

Specific surface area measurement conditions: BET multipoint method (relative pressure: 0.1 to 0.3 P / P05 points), measurement cell 6 c c

 The results are shown in Table 1.

Comparative Example 1

 A conventional potassium titanate whisker was produced in the same manner as in the above example except that the water-soluble metal salt was not added. The specific surface area was also measured for this potassium titanate whisker. Table 1 shows the results.

Comparative Example 2

Kokoku 7 - 2 3 2 2 Ji quasi 1 No. Example 1 of Japanese, a titanium Nsanka Li Umuu conductive © Lee Scar that the I Scar the surface and S n 0 ₂ and S b ₂ 0 ₃ coated Manufactured. That is, calcium titanate whiskers (commercial product, trade name: Tesmo D, manufactured by Otsuka Chemical Co., Ltd.) lOg was dispersed in 100 ml of water, and stirred with a stirrer. It was slurried by stirring for minutes. Next, this dispersed slurry was heated to 90 ° C in an oil bath, and 17 g of stannic chloride and 1.7 g of antimony chloride were added to the heated slurry at a concentration of 3.7 N. -Dissolved mixed salt in 30 g of hydrochloric acid aqueous solution The solution and 3.7 N-aqueous sodium hydroxide solution (92 ml) were stirred while maintaining the temperature of the hot slurry at 90 ° C and a pH of 8-9. After simultaneous addition over 1 hour, the pH was adjusted to 6.5 using a 3.7 N aqueous solution of hydrochloric acid, and the solution was allowed to stand still for 1 hour while maintaining the solution temperature at 90 ° C. Then cooled discharge the reaction solution to room temperature, filtered off solid, washed with water, dried, and heat treated for 2 hours at 6 0 0 ° C, was prepared the conductive U i scan mosquito one _(this The specific surface area was also measured for the whiskers of Table 1. The results are shown in Table 1.

From Table 1, it can be seen that the surface-coated potassium titanate whiskers of the present invention generally have an increased specific surface area as compared with the conventional potassium titanate whiskers and the conductive titanium whiskers. Water soluble It is clear that the increase is remarkable depending on the type of the metal salt.

Test example 1

 The product of the present invention obtained in Example 6 and the product of the present invention obtained in Example 7 were analyzed by X-ray fluorescence analysis. The potassium titanate whiskers of Comparative Example 1 were also analyzed by X-ray fluorescence analysis. Table 2 shows the results.

 The equipment and test conditions used for X-ray fluorescence analysis are as follows.

X-ray fluorescence analyzer: RIX-30000, manufactured by Rigaku Corporation

Pressure molding machine: manufactured by Shimadzu Corporation (Pressure = 7 t-10 t → 15 t press (anore milling))

Aluminum: C at No. 348 XM 1 32 mm inner diameter, manufactured by Rigaku Corporation

Table 2

 Unit%

From the above results, it is understood that the product of the present invention of Example 6 is coated with Fe ₂ O ₃ , and the product of the present invention of Example 7 is coated with ZrO _2, which is coated with L.

Example 8

Inventive product No. 1;

Using _{C u S 0 4 '5 H} 2 0 as a water-soluble metal salt, and except that the added amount of 2 0% in the same manner as in Example 1-7. A surface-coated disk of the present invention was produced.

Inventive product No. 2;

Using _{C u S 0 4 * 5 H} 2 0 as a water-soluble metal salt, and except that the added amount of 2 0% in the same manner as in Example 1-7, the surface covering window Lee ska present invention Manufactured one.

Blank N 0.1;

 A potassium titanate whisker was produced in the same manner as in Examples 1 to 7, except that no water-soluble metal salt was added.

Inventive product No. 3;

Using _{C u S 0 4 * 5 H} 2 0 as a water-soluble metal salt, the additive amount is 2 0%, and p H in the same manner as the actual Examples 1 to 7 except for adjusting the 8.0 Thus, a surface-coated whisker of the present invention was produced.

Blank No. 2;

 A potassium titanate whisker was produced in the same manner as in Examples 1 to 7, except that the pH was adjusted to 8.0 without adding a water-soluble metal salt.

The present invention product N o. 1 to 3 and bra down click N o. For 1 to each Taneu Lee's force one 2, measuring method of measuring the specific surface area and water absorption _(specific surface area, the the same is there.

The water absorption was measured as follows. First, 1 g of disc was collected in a beaker and dried at 110 ° C for 60 minutes. It was dried and cooled in a desiccator for 30 minutes. Water was dropped on this sample with a burette, and the point at which the thixotropy appeared (titration) was read and the water absorption was taken. Table 3 shows the results.

 Table 3

Furthermore, X-ray fluorescence analysis was performed on various whiskers of the present invention Nos. 2 to 3 and blank No. 1. Table 4 shows the results.

Table 4

 Unit%

 From Table 4, it can be seen that, in this example, the use of the water-soluble copper salt can provide a surface-coated whisker coated with copper oxide. Furthermore, Table 3 shows that the coating with copper oxide can provide surface-coated whiskers with significantly reduced water absorption.

Test example 2

 The Γ potential was measured by the following method for various whiskers.

Used equipment ;

Streaming potential measurement device: ZP-10B, manufactured by Shimadzu Corporation Data processing device: PC — 980 lF x, manufactured by NEC Corporation

Data processing software: ZP—10B—PC1Ver 2.12, Shimadzu Corporation

Sample filling cell: 2 mm, manufactured by Shimadzu Corporation

Glass filter paper: Diameter 16 mm, GB100R, manufactured by Adnotech Tohto Co., Ltd.

Sample preparation;

 (1) For 1 g of the sample, adjust the flowing liquid to 100 m1 (aqueous solution containing 0.001 mol liter of lithium chloride) to the target pH, and A solution having a liquid resistance of 800 Ω) was added, and the mixture was stirred for 10 minutes to disperse the sample to obtain an aqueous slurry.

 (2) The aqueous slurry was filled on glass filter paper using a 2 mm filling cell.

 (3) This was set in a streaming potential measuring device, the streaming potential was measured (22 to 26 ° C), and the data was processed by a data processing software.

 The results are shown in Figure 1. In Fig. 1, each symbol is as follows.

○: products of the present invention Example 1 (A 1 ₂ 0 ₃ coating)

Δ: Product of the present invention of Example 8 No. 3 (CuO coating) □: The present invention product of Example 6 (F e ₂ 0 ₃ coating)

V: The present invention product of Example 7 (Z r 0 ₂ coating)

 X: potassium titanate (commercial product, trade name: Tismo D, manufactured by Otsuka Chemical Co., Ltd.)

 From FIG. 1, it is clear that the surface covering whisker of the present invention has an inflection point. Since these are made by coating a metal oxide on a titanic acid palm whisker having no inflection point, the surface of the whisker is uniformly coated with the metal oxide. Is obvious.

Test example 3

 The surface-treated whiskers of Example 1 and the conductive whiskers of Comparative Example 2 were subjected to a transmission electron microscope (trade name: JEM210, manufactured by JEOL Ltd.) at a magnification of about 50,000. Observe at × 7 o

 In the surface-treated potassium whisker of Example 1, no irregularities were observed on the surface, and in spite of this, the specific surface area increased or the inflection point was recognized. This suggests that ultra-fine particles of a size that cannot be observed at a magnification of 50,000 times, that is, nanometers or smaller, cover the surface.

On the other hand, the conductive whisker of Comparative Example 2 had concaves and convexes on its surface and particles having a diameter of about 0.01 to 0.1 lum. Was observed covering the surface.

 From the above results, it can be seen that the surface-coated potassium titanate of the present invention is a novel substance that is different from the conventional conductive dye.

Test example 4

 In the same manner as in Test Example 3, the product No. 1 of the present invention of Example 8 was observed at a magnification of about 50,000 using a transmission electron microscope, and an electron micrograph of the product of the present invention was taken. The electron micrograph is shown in FIG.

 From FIG. 2, it can be seen that no irregularities due to the adhered copper oxide are observed on the surface of the product of the present invention.

Claims

The scope of the claims  ゥ The surface of the whiskers is characterized by being coated with at least one selected from ultra-fine particles of metal oxide and ultra-fine particles of metal hydroxide having a size of nm or less. Surface coating wheel force.  表面 The surface coating force according to claim 1, wherein the line graph showing the correlation between the electric potential and the PH has at least one inflection point.  混合 Mix and heat the raw material compounds for the production of whiskers, defibrate the resulting aggregate of temporary fibers in water, add the water-soluble metal salt or its aqueous solution to the resulting slurry, and then add the acid or alkali. And neutralizing the mixture, followed by filtration to separate a temporary fiber, followed by drying and heating to obtain a temporary fiber according to claim 1 or claim 2. Surface coated whisker.  4. The surface-coated whisker according to claim 1, wherein the whisker is a potassium titanate whisker.