JP2000290527A - Surface-modified aluminum borate whisker and resin composition containing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve slidability of a resin composition by blending a whisker whose surface is coated with a compound having a fluorocarbon chain. SOLUTION: For a compound having a fluorocarbon chain, a fluororesin such as a tetrafluoroethylene resin and the like, a fine particle of a fluororubber and a cationic, anionic or nonionic fluorine surfactant, or the like can be mentioned while a silane compound having a fluorocarbon chain (e.g. heptadecafluorodesiltrimethoxy silane) is preferable. An aluminum borate whisker is coated with the compound having a fluorocarbon chain by, for example, spraying an organic solvent having a fluorine compound dispersed onto the aluminum borate whisker which is stirred in a blender having a spraying device. Preferably 0.1-10 wt.% of the fluorine compound is added to the aluminum borate whisker. A resin composition to be used as a sliding member is obtained by blending this surface-modified aluminum borate whisker with a resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum borate whisker surface-modified with a specific fluorine compound and a resin composition using the same.
The resin composition using the whisker of the present invention has excellent slidability,
It is useful as a sliding member for gears, pulleys, brake pads, and the like.

[0002]

2. Description of the Related Art Resin compositions used for sliding members such as bearings and gears are made of a resin having excellent friction and wear resistance, such as polyamide, polyphenylene sulfide, and polyacetal, as a matrix. In addition, there is known a mixture of carbon fibers, silicon carbide whiskers, calcium carbonate whiskers, potassium titanate whiskers, aluminum borate whiskers and the like as reinforcing fibers. Such a resin composition for a sliding member is required to have not only a low coefficient of friction and excellent wear resistance, but also a contradictory performance of low damage to a mating material.

However, when carbon fibers and silicon carbide whiskers are used among the above-mentioned reinforcing fibers, the hardness is relatively high and the wear resistance of the material is excellent, but the aggressiveness to the mating material is large and the mating material is damaged. When calcium carbonate whiskers and potassium titanate whiskers are used, the aggressiveness to the mating material is low, but the hardness of the fiber itself is low, so that the abrasion resistance of the material is poor. Aluminum borate whiskers have an intermediate hardness between carbon fibers and potassium titanate whiskers, and are fibers having suitable hardness when used as a sliding member. JP-A-6-279689, JP-A-8-113711,
According to Japanese Patent Application Laid-Open No. 9-87533, etc., by blending aluminum borate whiskers and a solid lubricant in a resin, the tendency of damaging the mating material during sliding is small, and the sliding performance with a stable low friction coefficient is improved. It has been described that a sliding member having excellent wear resistance can be provided.

[0004]

In order to improve the slidability of the resin, it is generally known that a resin is mixed with a tetrafluoroethylene resin, graphite or the like as a solid lubricant. This method is effective at low speed and low load, but when used under severe conditions such as high speed and high load such as a continuously variable pulley, the surface of the aluminum borate whisker does not have self-lubricating properties, so There has been a problem that whiskers that have fallen off from the resin composition become abrasives and damage the mating material.

In order to solve this problem, a method of using a large amount of an adhesive such as a silane coupler has been studied for the purpose of improving the adhesion to the resin and preventing the whisker from falling off. It was not possible to prevent troubles caused by falling off. An object of the present invention is to improve the damage resistance of a mating material due to the dropout of aluminum borate whiskers generated under a high load environment, further improving the slidability of the whisker itself, and improving the slidability. An object of the present invention is to provide an excellent resin composition.

[0006]

Means for Solving the Problems In view of such circumstances, the present inventors have conducted intensive studies and studies and found that aluminum borate whiskers are coated with a compound having a fluorocarbon chain having excellent slidability. It has been found that by imparting lubricity to the whiskers, the desired object can be achieved by blending the whisker with the resin, thereby completing the present invention.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In the practice of the present invention, a typical aluminum borate whisker used is represented by the formula 9Al ₂ O ₃ .2B ₂ O ₃ or 2Al ₂ O ₃ .B
It has a composition represented by ₂ O ₃ , and its fiber diameter is usually in the range of 0.05 to 5 μm, and its fiber length is in the range of 2 to 100 μm.

Typical examples of the compound having a fluorocarbon chain used in the surface treatment of the present invention include fluororesins such as ethylene tetrafluoride resin, fine particles of fluororubber, cations, anions, and nonionic fluorosurfactants. Agent,
These are silane compounds having a fluorocarbon chain, and these can be used alone or in combination of two or more compounds.

As the surface treatment method, there are a dry method in which a solution in which a fluorine compound is dispersed in an organic solvent is sprayed on an aluminum borate whisker stirred in a blender equipped with a spray device, and a method in which an aluminum borate whisker is used. There is a wet method in which a fluorine compound is added to water or an organic solvent-dispersed slurry and the mixture is stirred, and any of these methods may be used for the treatment. If necessary, a silicate such as ethyl silicate, methyl silicate or isopropyl silicate or a condensate thereof may be used in combination with the fluorine compound.

The fluorine compound used in the present invention is
It is added so as to have a mixing ratio of 0.1 to 10% by weight with respect to the aluminum borate whisker. The compounding ratio is 0.1
If the amount is less than 10% by weight, the surface of the whisker cannot be sufficiently coated with the fluorine compound, and if the amount exceeds 10% by weight, the film covering the whisker becomes too thick to obtain a uniform film thickness. The properties are impaired.

The type of the resin used in the present invention is as follows.
Although it depends on various conditions such as required heat-resistant temperature and properties, for example, polyphenylene sulfide, polyimide, polyamide imide, poly-ether-terketone,
Polyethersulfone, nylon, polyacetal,
Polycarbonate, polybutylene terephthalate, polyolefin, liquid crystal polymer, ABS resin, fluororesin,
Epoxy resins, phenolic resins and the like can be mentioned.

In the practice of the present invention, the proportion of aluminum borate whiskers surface-treated with a compound having a fluorine-containing chain to be mixed with the resin is 10 to 300 parts by weight, preferably 20 to 250 parts by weight, per 100 parts by weight of the resin.
Parts by weight. If the blending ratio of the surface-treated aluminum borate whisker is less than 10 parts by weight with respect to the resin, sufficient slidability cannot be obtained, and if it exceeds 300 parts by weight, the melt viscosity of the resin becomes too large, resulting in extrusion. Processing and forming are difficult.

The resin composition according to the present invention is uniformly kneaded with a resin and a surface-treated aluminum borate whisker by a known method using a single-screw or twin-screw extruder. Further, if necessary, an antioxidant, an ultraviolet absorber, a heat stabilizer, a colorant, a dispersant, and other inorganic fillers can be added.

[0014]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Example 1 Average fiber diameter: 0.5 to 1.0 μm
m, an aluminum borate whisker having an average fiber length of 10 to 30 μm [trade name: Arbolex Y, manufactured by Shikoku Chemicals Co., Ltd.] 1000 g of ethyl silicate was stirred while a slurry was dispersed in 1 liter of water. Product name:
Ethyl silicate 28, manufactured by Colcoat Co., Ltd.] 10.0
g and heptadecafluorodecyltrimethoxysilane [trade name: TSL8233, manufactured by Toshiba Silicone Co., Ltd.]
A mixture of 10.0 g of the two liquids was added, followed by stirring for 1 hour, and then the solid content was separated by filtration and dried at 100 ° C. for 8 hours to form boric acid whose surface was covered with a fluorocarbon compound. Aluminum whiskers were obtained.

Example 2 Instead of heptadecafluorodecyltrimethoxysilane in Example 1, an ethylene tetrafluoride resin having an average particle diameter of 0.3 μm (PTF)
E) Fine particles [trade name: KTL-500F, Kitamura Corporation]
Ex. 10.0 g was added, and the same treatment as in Example 1 was performed. The same treatment was performed as described above to obtain an aluminum borate whisker covered with a fluorocarbon compound.

EXAMPLE 3 Aluminum borate whiskers surface-treated in Example 1 were mixed with a polyphenylene sulfide resin (abbreviated as PPS) according to the compounding ratio shown in Table 1 (trade name: T-1G, Toprene Co., Ltd.). )],
Polytetrafluoroethylene resin (abbreviated as PTFE) [Product name: KH
400H, manufactured by Kitamura Co., Ltd.], mixed well, kneaded using a twin screw extruder [TEM35B, manufactured by Toshiba Machine Co., Ltd.], and pelletized. The pellets thus obtained were molded using an injection molding machine with a mold clamping pressure of 30 tons to produce test pieces having a predetermined shape. Then, using a pin-on-disk type friction and wear tester [Model EFM-III-EN / F manufactured by Orientec Co., Ltd.], the mating material: SUS304, peripheral speed 2 m / sec, load 2.5 k
g, the test time was 5 hours, and the friction and wear test was performed in a non-lubricated state. These test results were as shown in Table 1.

[Embodiment 4] In Embodiment 3, Embodiment 1
The same treatment as in Example 3 was performed except that the aluminum borate whisker obtained in Example 2 was used instead of the aluminum borate whisker obtained in Example 2, and the physical properties of the obtained resin composition were examined. The results of these tests were as shown in Table 1.

[Comparative Example 1]
In place of the aluminum borate whiskers obtained in the above, average fiber diameter 0.5-1.0 μm, average fiber length 10-30 μm
m untreated aluminum borate whisker [trade name: Albolex Y, manufactured by Shikoku Chemical Industry Co., Ltd.]
The same treatment as in Example 3 was carried out except for using, and the physical properties of the obtained resin composition were examined. The test results are as shown in Table 1.

[Comparative Example 2]
A resin composition obtained by performing the same treatment as in Example 3 except that a calcium carbonate whisker [trade name: Whiscal A, manufactured by Maruo Calcium Co., Ltd.] was used instead of the aluminum borate whisker obtained in Step 3. The results of these tests were as shown in Table 1.

[Comparative Example 3]
A resin composition obtained by performing the same treatment as in Example 3 except that potassium titanate whiskers (trade name: Tismo N, manufactured by Otsuka Chemical Co., Ltd.) were used in place of the aluminum borate whiskers obtained in Step 1. When the physical properties of the product were examined, the test results were as shown in Table 1.

[Comparative Example 4]
In place of the aluminum borate whisker obtained in the above, the same treatment as in Example 3 was performed except that carbon fiber [trade name: Vesfight HTA-C6-SR, manufactured by Toho Rayon Co., Ltd.] was used. When the physical properties of the obtained resin composition were examined, the test results were as shown in Table 1.

[0023]

[Table 1]

As is clear from the friction and wear test results shown in Table 1, the resin composition to which the aluminum borate whisker surface-treated with the fluorine compound of the present invention is added has extremely excellent sliding properties. In particular, the resin composition obtained in Example 3 was excellent in abrasion resistance and low in coefficient of friction, so that the aggressiveness to the mating material was low, and it was recognized that the resin composition was a well-balanced optimal material for a sliding member. . Comparative Examples 1-4
Among Comparative Examples, Comparative Example 1 in which aluminum borate whiskers were blended exhibited relatively excellent properties, and in the case of calcium carbonate whiskers and potassium titanate whiskers of Comparative Examples 2 and 3,
Although the damage to the mating material is low, the amount of wear of the resin composition itself is extremely large, and there is a problem in the wear resistance of the material itself. In the case where the carbon fiber of Comparative Example 4 was blended, the wear resistance of its own material was at a high level, but the friction coefficient was high, so that the mating material was severely damaged and it was recognized that it was difficult to use as a sliding member. .

[0025]

The surface-modified aluminum borate whisker of the present invention has a self-lubricating property because the surface is coated with a compound having a fluorine-containing carbon chain. Despite having low aggressiveness to the material, it has excellent wear resistance and is suitable as a sliding member.

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Claims (3)

[Claims] 1. A surface-modified aluminum borate whisker having a surface coated with a compound having a fluorocarbon chain. 2. A surface-modified aluminum borate whisker whose surface is coated with a silane compound having a fluorocarbon chain. 3. A resin composition containing the surface-modified aluminum borate according to claim 1 or 2.