WO2003087255A1

WO2003087255A1 - Non-asbestos friction material

Info

Publication number: WO2003087255A1
Application number: PCT/JP2003/004687
Authority: WO
Inventors: Akinobu Nishiguchi
Original assignee: Nippon Valqua Industries, Ltd.
Priority date: 2002-04-15
Filing date: 2003-04-14
Publication date: 2003-10-23
Also published as: AU2003236246A1; JPWO2003087255A1

Abstract

A non-asbestos friction material comprising, as non-asbestos base fibers, (i) a basic magnesium sulfate fiber and (ii) an artificial glass fiber and/or wollastonite. It is preferred that basic magnesium sulfate fiber (i) be contained in a proportion of 20 to 90 wt.% based on the total (100 wt.%) of fibers (i) and (ii), the remainder consisting of artificial glass fiber and/or wollastonite (ii). Further, it is preferred that an organic fiber be contained in a proportion of 0.5 to 30 wt.% based on the weight (100 wt.%) of non-asbestos base fibers. Also preferably, the non-asbestos base fibers are contained in a proportion of 10 to 60 wt.% based on the weight (100 wt.%) of friction material. The provided non-asbestos friction material is excellent in human safety in the event that scattered abrasion dust is inhaled by human and exerts a buffering action.

Description

Description Non-asbestos friction material Technical field of invention

The present invention relates to a non-asbestos-based friction material,

A non-asbestos-based friction material that is used for friction washer in a washing machine or a brake shoe in a washing machine, has excellent safety to a human even when a scattered abrasion powder is sucked by a human, and has a buffering action. Problems of the prior art

It is used as a friction material, friction washer or brake shoe in clutch discs of automobiles and the like, and in brake mechanisms of washing machines. Such a friction material is easy to manufacture, has a high coefficient of friction, is excellent in wear resistance and rawness, has cushioning properties, and is flexible such that it does not break, for example, when wound along a brake wheel. It is desirable to have the property. Conventionally, such friction materials have been manufactured using asbestos as a base material, but the use of asbestos is currently restricted due to the adverse effects of asbestos on the human body.

Especially in automobiles, etc., with the improvement of engine performance, non-asbestos-based friction materials such as friction washers and pre-mixes that are strong enough to withstand use under severe conditions are strongly demanded. . In addition, with the downsizing and light weight of automobiles, the space around engines and motors is being reduced, and as a result, even friction materials that are small and light and have excellent friction performance (high friction coefficient) have been developed. It has been demanded. However, the non-asbestos-based friction material having a buffering effect has a problem that its strength is inferior to that of the asbestos-based friction material.

In order to solve the above-mentioned problems, the present inventors have conducted intensive research, and the applicant of the present application has disclosed, in Japanese Patent Application Laid-Open No. 6-2873222, non-asbestos-based base fibers, rubber materials, Non-asbestos-based friction materials containing phenolic resin, phenolic resin and white carbon. In addition, in the columns [001] to [001] of the publication, non-asbestos-based base fibers include inorganic fibers such as glass fibers, carbon fibers, steel fibers, ceramic fibers, sepiolite, and rock wool. Fiber, aromatic polyamide fiber, novoloid fiber, rayon, and other organic fibers.Especially, the combination of organic aromatic polyamide fiber and inorganic sepiolite provides excellent reinforcement effect. Is obtained. The non-asbestos-based friction material described in the publication was superior in strength, flexibility and friction performance as compared with the conventional one. Recently, however, it has become clear that sepiolite (a hydrated magnesium silicate fiber), a kind of natural mineral inorganic fiber, contains a small amount of tremolite, a kind of asbestos, as an impurity.

The friction material exerts its function by rubbing against the mating material, but at that time, wear powder is generated. Therefore, if tremolite, a type of asbestos, such as sepiolite, is mixed in, the abrasion powder will be scattered in the air, and if humans inhale the abrasion powder, there is a slight possibility of harm to health. . Purpose of the invention

The present invention is intended to solve the problems associated with the conventional technology as described above, and is excellent in human safety even when humans suck in the scattered abrasion powder. The purpose is to form and provide a non-asbestos-based friction material with almost the same strength and friction performance with good molding workability. Disclosure of the invention

The non-asbestos-based friction material according to the present invention is characterized in that it contains (i) basic magnesium sulfate fibers as non-asbestos-based base fibers, and (ii) artificial glass fibers and / or wollastonite. I have.

In the present invention, the basic magnesium sulfate fiber (i) is contained in a total of 100% by weight of the basic magnesium sulfate fiber (i) and the artificial glass fiber or wollastonite (ii). In an amount of 20 to 90% by weight, and artificial glass fiber and Z or wollastonite (ii) in an amount of 80 to 10% by weight.

In the present invention, the organic fibers are 0.5 to 30% by weight in 100% by weight of the non-asbestos-based base fiber. It is preferably contained in an amount of / ₀ .

Further, it is preferable that the non-asbestos base fiber is contained in an amount of 10 to 60% by weight in 100% by weight of the friction material.

Advantageous Effects of Invention According to the present invention, a non-asbestos-based friction material that is excellent in safety to humans even when the scattered wear powder is sucked by humans and has almost the same strength and friction performance as conventional friction materials is formed. It can be formed and provided with good workability. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the non-asbestos-based friction material according to a preferred embodiment of the present invention will be specifically described.

The non-asbestos-based friction material according to the present invention includes a non-asbestos-based base fiber, a rubber material, and, if necessary, an inorganic filler, a friction modifier, a thermosetting resin, and the like. (I) Basic magnesium sulfate fiber and (ii) artificial glass fiber and / or wollastonite are contained as essential components. The non-asbestos base fibers include the above-mentioned basic magnesium sulfate fiber (i) and artificial glass fiber and / or wollastonite (ii). during 0 0 wt%, basic magnesium sulfate fibers (i) 2 0-9 0 weight ^_0/0, preferably 3 0-8 0% by weight, particularly preferably 4 0-7 0% by weight, The remaining amount of artificial glass fiber and / or wollastonite (ii), that is, 80 to 10% by weight, preferably 70 to 20% by weight, particularly preferably 60 to 30% by weight Desirably, it is contained in an amount.

In particular, the basic magnesium sulfate fiber preferably has an average fiber length of 7 to 10 ^ m. The fiber length of the artificial glass fiber is preferably 100 μm or more, and more preferably 100 to 65 μιη. The fiber length of wollastonite is preferably 100 μm or more, and more preferably 100 to 800 m.

Non-asbestos-based fibers include aromatic polyamide fibers (aramid fibers), aliphatic polyamide fibers, and novoloid fibers (a phenolic resin fiberized and then cross-linked to form a three-dimensional molecular structure. ), Cellulose fibers, and rayon (regenerated fiber such as viscose rayon and the same ammonia rayon, such as senorelose force), preferably 100% by weight of the non-asbestos-based base fiber. It is desirable that it be contained in an amount of 5 to 30% by weight, more preferably 1.0 to 25% by weight, and particularly preferably 3.0 to 20% by weight.

As the rubber material, conventionally known rubber materials can be widely used. For example, styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), acrylonitrile-butadiene rubber (nitrile rubber, NBR) ) Gen-based rubbers such as chloroprene rubber (CR), butyl rubber (IIR), ethylene-propylene rubber (EPDM), Olefin rubbers such as acryl rubber (ACM) and fluorine rubber (FKM); silicone rubber (Q); and urethane rubber (AU).

Examples of the inorganic filler include zinc oxide, clay, tanolek, barium sulfate, calcium carbonate, calcium hydroxide, and mica.

Examples of other components that can be blended include a friction modifier. Examples of the friction modifier include white carbon, carbon black, force dust, calcium carbonate, barium sulfate, alumina, graphite (graphite), and molybdenum disulfide.

The method for producing a non-asbestos-based friction material according to the present invention is basically the same as the method for producing an asbestos-based friction material, and is one of the raw materials conventionally used for producing the asbestos-based friction material. Replacing asbestos as a base fiber with a non-asbestos base fiber containing (i) basic magnesium sulfate fiber, (ii) artificial glass fiber and Z or wollastonite, and a binder such as rubber material; If necessary, a thermosetting resin, a friction modifier, an inorganic filler, etc. may be used together with the rubber compounding chemicals.

For example, a material for a non-asbestos-based friction material is prepared by mixing the non-asbestos-based base fiber with a friction modifier such as white carbon, and kneading the resulting mixture with a binder and a rubber compounding chemical. Next, the material is extruded into a sheet by an extruder. Next, the sheet is pre-dried at a temperature of, for example, 40 to 50 ° C. for about 10 to 50 hours, and then, for example, at a temperature of about 80 to 100 ° C. for about 1 to 5 hours. After additional drying, it is molded at a temperature of, for example, 170 to 190 ° C. and a calo heat and pressure of 3 to 6 MPa.

Further, if the front and back surfaces of the formed sheet material are polished and punched or cut into a predetermined shape and size, the non-asbestos-based friction material according to the present invention can be obtained. The non-asbestos-based friction material according to the present invention includes the basic magnesium sulfate fiber (i) and the (man-made) glass fiber and / or wollastonite in such a weight ratio. When (ii) is included, the non-asbestos-based friction material can be manufactured with good molding workability, and the non-asbestos-based friction material with the obtained stiffness is suitable for a time when the strength and wear resistance are particularly well-balanced and excellent. There is.

If the amount of the basic magnesium sulfate fiber is less than the above range, there is a tendency that the workability of forming the sheet-like material is reduced, and the wear resistance of the obtained non-asbestos-based friction material is reduced. If the amount of the basic magnesium sulfate fiber is larger than the above range, the molding workability is good, but the mechanical strength and abrasion resistance tend to be lower than those of the conventional non-asbestos-based friction material. The invention's effect

The non-asbestos-based friction material according to the present invention includes a specific non-asbestos-based base fiber) basic magnesium sulfate fiber, and (ii) “artificial glass fiber and / or wollastonite”. High coefficient of friction and excellent molding workability. Therefore, according to the present invention, it is possible to provide a non-asbestos-based friction material that is excellent in safety for humans and has a buffering action even when humans suck the scattered wear powder. Example

Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

The test conditions and test methods used in the following Examples and Comparative Examples are as follows.

[Test conditions and methods]

a ： Strength (tensile test)

Conforms to JIS-K6301.

shape; Speed; 30 Oram / ⁷ minutes.

b: Wear resistance and coefficient of friction (Torsion endurance test)

Conforms to the automotive standard JASOC 105-74 (Test method for performance on clutch tables). Sample dimensions: outer diameter 55mm x inner diameter 35mm x thickness 1.5mm.

Torsion angle: ± 6 °.

Number of twists: 470 times (cpm).

Temperature; normal temperature.

Load; 588 N. ni (60 kg f).

Number of tests: 2 million.

The coefficient of friction can be calculated from the torque value by measuring the torque value. Example 1

A rubber paste was prepared by dissolving the thermosetting resin (type: phenolic resin), nitrile rubber and the compounding compound of rubber in a solvent (acetone) as shown in Table 1.

The solvent was mixed in the rubber paste in an amount of 250 parts by weight per 100 parts by weight of the rubber paste.

Separately, an organic aramide fiber, an inorganic basic magnesium sulfate fiber and an artificial glass fiber, and a friction modifier are mixed, and the resulting mixture is put into a rubber paste and kneaded, and the mixture is kneaded to obtain non-asbestos friction. The material of the material was prepared.

This material was extruded into a sheet by an extruder. The thickness of the sheet was 3. Omm. Next, this sheet is preliminarily dried at a temperature of 50 ° C for about 20 hours, then dried at a temperature of 100 ° C for 3 hours, and then heated and pressurized at a temperature of 170 ° C and 4 MPa. It was vulcanized below. Further, the front and back surfaces of the sheet were polished and cut into a predetermined shape and size to obtain a non-asbestos-based friction material.

Strength and wear resistance of the obtained non-asbestos-based friction material according to the test method described above. Properties and coefficient of friction.

The strength of the obtained non-asbestos-based friction material was 15 MPa, the abrasion resistance was 0.334 mm, and the workability of forming a sheet was good (〇).

The results are shown in Table 1.

[Blending composition]

(a) a rubber material (nitrile rubber): 20 weight ^_0/0,

(b) Rubber compounding chemicals (vulcanizing agent and vulcanizing aid): 5% by weight,

(c) Thermosetting resin (phenol resin): 10% by weight,

(d) Non-asbestos base fiber:

(I) made basic magnesium sulfate fibers ( "MOS-HIGE A (registered trademark)" Series (Ube Material Co.): 12 wt ^_0/0

Physical properties: average fiber length 7 to 10 μm, average fiber diameter 0.5 to 1 m, specific surface area less than 15 m ² Zg (measured by BET method), true specific gravity 2.3, apparent specific gravity About 0.07, pH about 9.5.

(Mouth) (Synthetic) Glass fiber ("Ravinas" series (made by LAPINUS FIBRES BV): 18% by weight

Physical properties: Average fiber length 1 25 m, an average fiber diameter of 9 m, a specific surface area of 0. ² m 2 / g, true specific gravity 2.75.

(C) wollastonite (NYCO Minerals, manufactured by Inc Co., Ltd.): 0 Weight ^_0/0

Physical properties: average fiber length 600 μm, average fiber diameter 40 μm, true specific gravity 2.9.

(2) Organic fiber (aramid fiber): 5% by weight

( _e ) Friction modifier (type: cash dust, calcium carbonate, etc.): 30% by weight, total ((a) + (b) + (c) + (d) + (e)) = 100% by weight> Examples 2 to 4, Comparative Example:! ~ Four A non-asbestos-based friction material was manufactured in the same manner as in Example 1 except that the amounts of the components were changed as shown in Table 1 in Example 1, and the same tests as in Example 1 were performed. Was.

Table 1 shows the results.

The evaluation criteria for workability in Table 1 are as follows.

Table 1 (Blend composition for non-asbestos-based friction material, workability, physical properties of obtained friction material, etc.)

* 1: It is difficult to form a product with extremely poor workability. Therefore, characteristics cannot be measured.

Industrial applicability

As described above in detail, the non-asbestos-based friction material according to the present invention has a large strength and a high coefficient of friction, is excellent in molding workability, has a buffering effect, and furthermore, the friction material is worn out. However, it is excellent in safety for humans even when humans suck the scattered wear powder, and is suitably used as a friction washer in a clutch disc or a brake shoe in a washing machine.

Claims

The scope of the claims

1. A non-asbestos-based friction material comprising (i) basic magnesium sulfate fiber and (ii) artificial glass fiber and Z or wollastonite as non-asbestos-based base fibers.

2. In a total of 100% by weight of the basic magnesium sulfate fiber (i), the artificial glass fiber and Z or wollastonite (ii), the basic magnesium sulfate fiber (i) is 20 to 9%. The non-artificial glass fiber according to claim 1, wherein the artificial glass fiber Z or wollastonite (ii) is contained in an amount of 80 to 10% by weight in an amount of 0% by weight. Asbestos-based friction material.

3. The organic fiber according to claim 1 or 2, wherein the organic fiber is contained in an amount of 0.5 to 30% by weight in the 100% by weight of the non-asbestos-based base fiber. The non-asbestos-based friction material according to any one of the above.

4. The method according to any one of claims 1 to 3, wherein the non-asbestos-based base fiber is contained in 100 to 60% by weight of the friction material in an amount of 10 to 60% by weight. The non-asbestos-based friction material according to any one of the above.