JPH07188646A - Friction material composition, friction material obtained using the same, and production or friction material - Google Patents

Abstract

PURPOSE:To obtain a friction material compsn. with stable friction characteristics even at high temp. and load and obtain a friction material from the compsn. CONSTITUTION:A friction material compsn. comprises a fibrous base material, a friction modifier, a binder, and a cellulose compd. and is obtd. by impregnating the base material with the cellulose compd., drying the impregnated material, impregnating it with a mixture contg. the modifier and the binder, and molding the resulting product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material composition, a friction material using the same, and a method for producing the friction material.

[0002]

Brake linings, disc pads and clutch facings are generally used as friction materials for automobiles. Conventionally, asbestos (asbestos) has been used as a base material, but development of a non-asbestos friction material is desired due to the problem of asbestos pollution. Further, as the performance of automobile engines is improved, it is desired to improve the friction characteristics (friction coefficient, wear rate) and mechanical characteristics of friction materials. Furthermore, recently, the usage conditions have become severe, and high-speed rotation strength at high temperatures has been required. At present, friction materials using glass fiber, carbon fiber, aromatic polyamide fiber, rock wool, ceramic fiber, various steel fibers, etc. have been developed and used as a substitute for the asbestos base material. However, since these base materials have higher elasticity and hardness and lower heat resistance than conventional asbestos, there are various problems when used as a friction material, and the above-mentioned required performance is not satisfied.

[0003]

As a friction material which uses an asbestos substitute material and withstands a high load at a high temperature, the friction material itself is preliminarily treated at a high temperature (for example, JP-A-56-13184).
6, gazette 59-113038 gazette, gazette 60-14.
No. 5302, etc.), but this involves a high cost and a decrease in mechanical strength. Those to which a special friction modifier is added (for example, JP-A-60-96625 and JP-A-60-9233).
No. 2, gazette, No. 62-190232, etc.),
Since the conventional binder lacks heat resistance and adhesiveness, its effect cannot be fully exhibited. In addition, although aramid fibers and polyimide resin powder with high heat resistance are added to the base material, the heat resistance of the binder holding the base material and the friction modifier is not sufficient and high temperature strength cannot be obtained. . Even if you try to obtain a friction material using a heat resistant resin as a binder,
The conventional manufacturing method is industrially and technically difficult.

The present invention provides a friction material composition for solving the above-mentioned problems and obtaining stable friction characteristics even under high temperature and high load conditions, a friction material using the same and a method for producing the friction material. Is.

[0005]

The present invention relates to a friction material composition containing a fibrous material base material, a friction modifier, a binder and a cellulose compound, a friction material formed by molding the friction material composition and a fibrous material. The present invention relates to a method for producing a friction material in which a base material is impregnated with a cellulose compound, and after being dried, an admixture containing a friction modifier and a binder is impregnated and molded.

In the present invention, the base material of the fibrous material includes inorganic fibers such as glass fiber, carbon fiber, rock wool and ceramic fiber, metal wire such as iron wire, organic resin such as phenol resin fiber and aromatic polyamide resin fiber. Etc. are used, and there is no particular limitation, but it is preferable to use glass fiber because it is easy to process and inexpensive. The form of the base material of the fibrous substance includes non-woven fabrics such as chops, filaments, rovings, twisted yarns, yarns, mats and felts, paper sheets, and woven fabrics, but is not particularly limited.

When glass fiber is used as the base material for the fibrous material, the amount thereof is 25 to 65% by weight in the obtained friction material.
It is preferable to include it because it has a good balance between the friction characteristics and the strength. A more preferable amount is 30 to 55% by weight. If necessary, glass fibers may be mixed with one or more of organic fibers, carbon fibers, rock wool, ceramic fibers, metal wires, metal filaments, and the like.

Friction modifiers include calcium carbonate, calcium silicate, magnesium carbonate, barium sulfate, clay, talc, graphite, carbon black, alumina, mica, fluorspar, zirconia, hematite, magnetite, silica, antimony sulfide, trioxide. Powders of various inorganic substances such as antimony, lead sulfide, iron sulfide, zinc sulfide, molybdenum sulfide, sulfur, zinc oxide and the like, powders of metal such as short fibers, copper, iron and lead, powders of cashew dust, cured melamine resin ( Powders of organic substances such as melamine dust), rubber dust, and powders of cured resins of various resins are used.

The amount of friction modifier is 10 in the resulting friction material.
A stable friction coefficient can be obtained when the content of -60% by weight is contained,
It is preferable because it has a good balance with the amount of wear. It is more preferably 20 to 40% by weight.

A phenol resin is preferably used as the binder. The reason is that it has excellent heat resistance and adhesiveness, is inexpensive, and by combining with friction modifiers such as melamine dust, antimony trioxide, and copper powder, the friction characteristics of the thermosetting resin are better than those of other thermosetting resins. This is because the temperature dependence can be reduced. Among the phenolic resins, unmodified and resol type resins are more preferable. Further, a thermosetting resin such as melamine resin, urea resin, polyamideimide resin, polyimide resin, epoxy resin or crosslinkable rubber may be used together with the phenol resin to the extent that heat resistance is not affected. The amount of the binder is 10 as solid content in the obtained friction material.
A content of -50 wt% is preferable because the binding force between the fibrous base material and the friction modifier is excellent and the friction coefficient and wear rate can be easily adjusted.

As the cellulose compound, a cellulose ester obtained by esterifying a hydroxyl group of cellulose, an etherified cellulose ether, or the like is used, and when the amount is 2 to 30% by weight based on the base material of the fibrous material, the friction characteristics are obtained. Is preferable and is preferable. More preferably 5
It is 20% by weight.

A method of manufacturing a friction material using the above materials will be described. First, a fibrous substrate to which a cellulose compound is attached (hereinafter referred to as a cellulose-treated substrate) is obtained. Then, a mixture (slurry) obtained by adding a friction modifier to a binder solution and mixing the mixture is impregnated into the above-mentioned cellulose-treated base material, and the mixture is uniformly adhered to the cellulose-treated base material, followed by drying or the like to form a solvent. To obtain a coated string. Next, the coated string is put in a mold or the like and subjected to thermocompression molding, and then the molded product is heat-treated under predetermined heating conditions to cure the binder and obtain a friction material.

[0013]

EXAMPLES Examples of the present invention will be described below. Examples 1 to 6 and Comparative Example (1) Cellulose Compound Treatment of Glass Fiber Glass Fiber (Fuji Fiber Glass, trade name FER2
310 (2.3 g / m) was immersed in an aqueous solution of a cellulose compound (all manufactured by Wako Pure Chemical Industries, Ltd.) shown in Table 1 (however, only Examples 1 to 6) and dried to obtain a cellulose-treated substrate. The amount of adhesion was adjusted by changing the concentration of the cellulose compound in the aqueous solution (concentration is 2.5 wt% aqueous solution in Example 1 and 5.0 wt% aqueous solution in Examples 2 to 6).

[0014]

[Table 1]

(2) Preparation of Friction Modifier 12 parts by weight of barium sulfate (manufactured by Sakai Chemical Co., BC), 12 parts by weight of talc (manufactured by Wako Pure Chemical Industries, chemical), calcium carbonate (manufactured by Takehara Chemical Co., Ltd., trade name) Sunlight SL-1500) 1
2 parts by weight and 30 parts by weight of calcium silicate short fibers (manufactured by NYCO, USA, product name Wollastonite) are mixed, an inorganic powder, methylated melamine resin (made by Nippon Carbide,
Trade name S-260) at 150 ° C for 1 hour, 180 ° C for 4 hours
10 minutes by weight of melamine dust obtained by crushing a cured product obtained by heating for 2 hours at 210 ° C. for 2 hours in order, and iron oxide (Fe ₂ O ₃ ) powder (manufactured by Wako Pure Chemical Industries, Ltd.) , For chemistry, average particle size: 15-100μ
m) 4 parts by weight and copper powder (manufactured by Wako Pure Chemical Industries, copper foil powder for chemical use, average thickness 2 μm, minor axis 50 μm, major axis 70 μm)
10 parts by weight were mixed and mixed by a V-type mixer to obtain a friction modifier.

(3) Preparation of Binder As a thermosetting resin solution, 50 parts by weight of resole phenolic resin (trade name TD-2040C, manufactured by Dainippon Ink and Chemicals, solid content 100% by weight) was added to methyl ethyl ketone (ME).
K) Thermosetting resin solution dissolved in 50 parts by weight (solid content 5
0% by weight) was used. Further, as a rubber solution, nitrile butadiene (manufactured by Nippon Zeon, trade name Nippol1041,
15 parts by weight of solid content 100% by weight, sulfur (manufactured by Hosoi Chemical,
A rubber solution (solid content: 15% by weight) having 1.2 parts by weight of finely divided sulfur) and 0.3 parts by weight of zinc oxide (Wako Pure Chemical Industries, Ltd. for chemicals) dissolved in 93.5 parts by weight of MEK was used.

(4) Manufacture of friction material Next, 30 parts by weight of the thermosetting resin solution and 5 parts of the rubber solution
3.3 parts by weight was stirred and mixed with a high speed mixer to obtain a uniform solution. Then add to this solution the friction modifier 2 prepared above.
7 parts by weight was added and stirred to obtain a mixture having a solid content of 45.3% by weight. The amount of the cellulose-treated base material (glass fiber for the comparative example) shown in Table 2 was dipped and impregnated in the mixture, and a predetermined amount of the mixture was adhered to the mixture.
After being dried for a minute, coated strings having the admixture in the amounts shown in Table 2 were obtained.

[0018]

[Table 2]

After that, the coated string to which the above mixture is attached is filled in a mold, and the mixture is heated at 160 ° C. for 15 minutes and the pressure is 1.96 × 10.
Molded under the condition of ⁷ Pa (200 kg / cm ² ) 5 mm × 50 mm ×
A 50 mm compact was obtained. After that, at 180 ℃ for 1 hour, 2
Post-curing was performed in the order of 10 ° C. for 2 hours and 240 ° C. for 4 hours, and both surfaces of the molded body were polished with a sander to obtain a friction material. The friction materials obtained in the examples and the comparative examples were cut into 25 mm square pieces to obtain friction property test pieces. This test piece is JIS D 44
Pressing against constant speed friction tester specified in 11 4.9 ×
Installed at 10 ⁵ Pa (5 kg / cm ² ) and operated, 100
The friction coefficient and wear rate (cm ³ / kgf · m) at ° C, 200 ° C and 300 ° C were measured. The results are shown in Table 3.

[0020]

[Table 3]

As is clear from Table 3, the comparative examples have a large temperature dependence of the friction coefficient and a high wear rate, and are inferior in friction performance. On the other hand, in the examples, the temperature dependence of the friction coefficient is small, and the wear rate is also low, so that the friction performance is excellent.

[0022]

EFFECTS OF THE INVENTION According to the present invention, a friction material having excellent friction performance at high temperature can be obtained and a friction material composition having the above effects can be provided.

Claims (3)

[Claims] 1. A friction material composition comprising a fibrous base material, a friction modifier, a binder and a cellulose compound. 2. A friction material obtained by molding the friction material composition according to claim 1. 3. A method for producing a friction material, comprising the steps of impregnating a fibrous base material with a cellulose compound, drying and then impregnating a mixture containing a friction modifier and a binder, and molding.