JP2002309234A - Friction material composition, manufacturing method of the same and friction material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction material composition suitable for a friction material, in which a dropping off of a metal fiber and occurance of segregation are less, an oxidation deterioration of the metal fiber is inhibited and a sound vibration performance, an effect and an abrasion-resistance property are excellent, to provide a manufacturing method of the friction material composition, a friction material using the composition. SOLUTION: The friction material composition contains a fibrous substance, a binder and a friction adjusting agent and contains 10-50% by weight of the metal fiber of which the surface is covered by one or more kinds of elastomer of butyl rubber, silicone rubber and fluororubber. The manufacturing method of the friction material composition comprises covering the metal fiber by one or more kinds of elastomer of butyl rubber, silicone rubber and fluororubber, adding and mixing a material containing other fibrous substances, the binder and the friction adjusting agent. The friction material is formed by molding, heating and pressurizing, from the friction material composition or the friction material composition.

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 suitable for a friction material such as a disc brake pad and a brake lining used for braking automobiles, railway vehicles, various industrial machines, and the like, and production of the friction material composition. And a friction material using the friction material composition.

[0002]

2. Description of the Related Art Friction materials are used in automobiles, railway vehicles, various industrial machines and the like for braking. As the friction material, non-asbestos disc brake pads are currently the mainstream, and as shown in JP-B-59-4462 and JP-A-6-184525, steel fibers, brass fibers, and copper fibers are used as reinforcing fibers. A combination of organic fibers such as metal fibers such as acrylic fibers, aramid fibers, and phenol fibers, and inorganic fibers such as rock wool, potassium titanate fiber, alumina silica fiber, and carbon fiber is used.

[0003] However, when a material constituting a friction material such as a conventional non-asbestos-type disc brake pad is dry-mixed, there is a problem that the material is dropped, particularly the metal fibers are dropped. Metal fibers have a large specific gravity and a large fiber diameter as compared with other materials used for the friction material, and thus are liable to fall off and become non-uniformly dispersed. When the metal fibers fall off, the friction performance, wear performance and physical properties of the friction material become non-uniform, and cracks may occur due to non-uniform dispersion of the metal fibers. Further, in a friction material containing a large amount of metal fibers, the friction performance may be changed due to oxidation of the metal fibers, and the sound and vibration performance such as squealing and abnormal noise may be deteriorated.

As a countermeasure against the above problem, there is a method of coating metal fibers with cashew nut shell oil or linseed oil to prevent the material from falling off. But with the above method,
Due to insufficient adhesive force of cashew nut shell oil or linseed oil, dispersibility of metal fibers is insufficient, and a drying process to remove organic solvent is necessary, and it is necessary to manufacture mixed powder. There were drawbacks such as a complicated process.

[0005]

According to the first and second aspects of the invention, the metal fibers are less likely to fall off and segregate, the oxidation deterioration of the metal fibers is suppressed, and the sound vibration performance, effectiveness and wear resistance are excellent. An object of the present invention is to provide a friction material composition suitable for a friction material. The invention according to claim 3 provides a method for producing a friction material composition suitable for a friction material having little metal fiber falling off and segregation, suppressing oxidative deterioration of the metal fiber, and having excellent sound vibration performance, effectiveness and abrasion resistance. To provide. The fourth aspect of the present invention is to provide a friction material which suppresses oxidative deterioration of metal fibers and has excellent sound vibration performance, effectiveness and wear resistance.

[0006]

The present invention provides a fibrous material,
In a friction material composition containing a binder and a friction modifier, the surface has one of butyl rubber, silicone rubber and fluoro rubber.
Metal fibers coated with more than one type of elastomer
The present invention relates to a friction material composition containing 50% by weight. Also,
The present invention relates to a friction material composition in which an elastomer is 2 to 15 parts by weight based on 100 parts by weight of a metal fiber. Also,
The present invention is characterized in that a metal fiber is coated with at least one kind of elastomer among butyl rubber, silicone rubber and fluorine rubber, and then a material containing another fibrous substance, a binder and a friction modifier is added and mixed. And a method for producing a friction material composition. Furthermore, the present invention relates to a friction material obtained by subjecting the above-mentioned friction material composition or the friction material composition produced by the above-mentioned method to heat and pressure molding.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the elastomer covering metal fibers is made of butyl rubber (IIR rubber) or silicone rubber (S) in terms of dispersibility, airtightness and oxidation resistance.
It is appropriate to use a liquid material of i-type rubber) and fluorine rubber (FR-type rubber), and it is preferable to coat with at least one kind of elastomer. It is preferable that these elastomers are used without using an organic solvent and, if necessary, are compounded with sulfur or a curing accelerator.

[0008] The amount of the elastomer to be coated is
The range of 2 to 15 parts by weight relative to 00 parts by weight is preferable,
The range is more preferably from 4 to 13 parts by weight, and even more preferably from 6 to 12 parts by weight. If the amount is less than 2 parts by weight, dispersibility, airtightness and oxidation resistance tend to decrease, and brake squeal tends to deteriorate. If the amount exceeds 15 parts by weight, fade resistance tends to deteriorate.

Further, the metal fiber whose surface is coated with the elastomer is 10 to 50% by weight, preferably 15 to 45% by weight, more preferably 20 to 40% by weight in the total composition.
If it is less than 10% by weight, the effectiveness and abrasion resistance are reduced, and if it is more than 50% by weight, brake squeal and aggressiveness of a mating material are increased. Examples of the metal fiber used in the present invention include steel fiber, brass fiber, copper fiber, phosphor bronze fiber and the like, and among them, steel fiber and brass fiber are preferably used.

It is preferable that the metal fiber is coated with the elastomer by pressure kneading with a kneader in order to uniformly coat the metal fiber. The viscosity of the elastomer is 5 to 1000 Pa.s in terms of ease of coating on the metal fiber. s, and preferably 20 to 500 Pa.s. More preferably, it is in the range of s.

The material of the friction material portion in the present invention can be applied to any of a semi-metallic type, a low steel type, and a non-steel type, and is not particularly limited. In addition, the material used for the friction material is, in addition to the above metal fibers and elastomers, generally known materials, for example, aramid fiber, acrylic fiber, phenol fiber, ceramic fiber, rock wool, potassium titanate fiber, carbon fiber Fibrous substances such as fibers, phenolic resins, epoxy resins, melamine resins,
Thermosetting resin such as cashew resin, NBR, SBR, IR
Binders containing rubber compositions such as, cashew dust, organic friction modifiers such as rubber dust, barium sulfate, graphite, coke, antimony trisulfide, molybdenum disulfide, mica,
Inorganic friction modifiers such as zirconia, silica, alumina, calcium carbonate, and magnesium carbonate are used, and metal powders such as brass, phosphor bronze, copper, and zinc are added as necessary.

The content of the fibrous material including the metal fibers coated with the elastomer in the above is 10 to 10 in the total composition.
It is preferably 60% by weight, more preferably 15 to 55% by weight. The content of the binder is preferably 5 to 20% by weight in the whole composition, and 10 to 1% by weight.
More preferably, the content is 5% by weight. The content of the organic friction modifier is preferably from 3 to 20% by weight, more preferably from 6 to 15% by weight in the whole composition. The content of the inorganic friction modifier is 2% in the total composition.
The content is preferably 0 to 50% by weight, more preferably 25 to 45% by weight.

The content of the metal powder added as necessary is preferably 5 to 30% by weight, more preferably 10 to 25% by weight, based on the whole composition. These components are blended so that the total composition becomes 100% by weight.

The friction material according to the present invention is obtained by coating a metal fiber with an elastomer, adding a material containing another fibrous substance, a binder, and an organic / inorganic friction modifier, and uniformly mixing the mixture. Pre-molded, then insert the backing metal and the pre-molded body into the mold, mold by the heat and pressure molding method, then perform heat treatment, and if necessary, perform scorch treatment to remove organic components on the surface Obtained by going.

When the materials are mixed, it is preferable to mix them by a dry method.
-180 ° C is preferred, and 140-170 ° C is more preferred. The pressure is preferably 20 to 60 MPa, and 30 to 50 M
Pa is more preferred. The heat treatment temperature is preferably from 180 to 250C, more preferably from 200 to 230C. The scorch treatment performed as necessary includes a method of pressing a hot plate against a friction member, a method of heating with a direct fire such as a gas flame, and the like, and is not particularly limited. Further, as for the conditions of the scorch processing, the processing may be performed by selecting conditions suitable for the material.

[0016]

The present invention will be described below with reference to examples. Example 1 4 parts by weight of liquid butyl rubber (hereinafter referred to as liquid IIR) having a viscosity of 70 Pa · s and liquid nitrile butadiene rubber (hereinafter referred to as liquid) having a viscosity of 70 Pa · s based on 100 parts by weight of metal fiber (steel fiber and brass fiber) 4 parts by weight (referred to as NBR) were kneaded with a kneader at a pressure of 49 MPa for 5 minutes, and the metal fibers were coated with liquid IIR and liquid NBR to obtain a material A shown in Table 1. Next, the other components shown in Table 2 were weighed and mixed in a mixer at a rotation speed of 3000 r / min for 4 minutes to obtain a friction material composition.

Example 2 2 parts by weight of a liquid silicone rubber (hereinafter referred to as liquid Si rubber) having a viscosity of 70 Pa · s with respect to 100 parts by weight of a metal fiber (steel fiber and brass fiber) are kneaded with a kneader at a pressure of 49 MPa for 5 minutes. After kneading, the metal fibers were coated with liquid Si rubber to obtain material B shown in Table 1. Next, the other components shown in Table 2 were weighed and mixed in a mixer at a rotation speed of 3000 r / min for 4 minutes to obtain a friction material composition.

Example 3 15 parts by weight of a liquid IIR having a viscosity of 70 Pa · s with respect to 100 parts by weight of a metal fiber (steel fiber and brass fiber) are kneaded with a kneader at a pressure of 49 MPa for 5 minutes to coat the metal fiber with a liquid IIR. Then, a C material shown in Table 1 was obtained. Then Table 2
The other components shown in Table 2 were weighed in the amounts shown in Table 2, and mixed with a mixer.
The mixture was mixed at a rotation speed of 0 r / min for 4 minutes to obtain a friction material composition.

Example 4 Using the material A obtained in Example 1, the other components shown in Table 2 were weighed and mixed in a mixer at a rotation speed of 3000 r / min for 4 minutes to obtain a friction material. A material composition was obtained.

Example 5 Using the material A obtained in Example 1, other components shown in Table 2 were weighed and mixed in a mixer at a rotation speed of 3000 r / min for 4 minutes. A material composition was obtained.

COMPARATIVE EXAMPLE 1 Using the material A obtained in Example 1, other components shown in Table 2 were weighed and mixed in a mixer at a rotation speed of 3000 r / min for 4 minutes. A material composition was obtained.

Comparative Example 2 Using the material A obtained in Example 1, the other components shown in Table 2 were weighed and mixed in a mixer at a rotation speed of 3000 r / min for 4 minutes to obtain a friction material. A material composition was obtained.

Next, the friction material compositions obtained in Examples 1 to 5 and Comparative Examples 1 and 2 were each preformed, and then the backing of the disc brake pad and the preformed body were inserted into a mold.
Thereafter, it was heated and pressed at 150 ± 5 ° C. and 49 MPa for 5 minutes. Further, heat treatment was performed at 200 ° C. for 5 hours, and after cooling, polishing and surface scorch treatment were performed at 470 ± 10 ° C. for 5 minutes to obtain a disc brake pad.

[0024]

[Table 1]

[0025]

[Table 2]

Next, Examples 1 to 4 according to the present invention obtained above will be described.
Composition and Disc Brake Pad of Comparative Example 5 and Comparative Example 1
Comparative tests were performed on the friction material compositions of Nos. 1 to 2 and the disc brake pads. Table 3 shows the test results. The test conditions are as follows.

(1) Effectiveness level A dynamo test was conducted in accordance with JASO C402, and the friction coefficient (μ average value) under a vehicle speed of 50 km / h was compared with the friction coefficient (minimum μ) under a fade condition. (2) Brake squeal An actual vehicle test was performed according to JASO C402, the brake squeal during the test was measured, and the occurrence rate of brake squeal of 75 dB or more was determined.

(3) Pad wear and mating material wear In the above test (1), the wear after the test was determined. (4) Dropping of Metal Fibers Each friction material composition was separately put into a polyethylene bag, shaken 10 times, and the amount of the metal fiber dropped at the bottom of the bag was evaluated. The tests (1) to (3) were all performed using Nissan Motor Co., Ltd., model name: Primera brake unit.

[0029]

[Table 3]

As shown in Table 3, the friction material composition according to the example of the present invention has a small amount of metal fibers and has an acceptable level, and the friction material composition according to the example of the present invention is used. It is evident that the used brake pad has a high effectiveness level, and the brake squeal, the pad wear amount and the mating material wear amount are small. On the other hand, the friction material composition of the comparative example had a low level of metal fiber detachment and was at an acceptable level, whereas the disc brake pad using the friction material composition of Comparative Example 1 had a low effectiveness level and had a low pad wear amount. The disc brake pad using the friction material composition of Comparative Example 2 had a large amount of brake squeal and abrasion of the mating material.

[0031]

The friction material composition according to the first and second aspects provides a friction material which is less likely to fall off and segregate metal fibers, suppresses oxidative deterioration of metal fibers, and is excellent in sound vibration performance, effectiveness and wear resistance. can do. The friction material composition obtained by the method according to the third aspect provides a friction material which has less falling off and segregation of metal fibers, suppresses oxidative deterioration of metal fibers, and has excellent sound vibration performance, effectiveness and wear resistance. it can. The friction material according to claim 4 suppresses oxidative deterioration of the metal fiber, and has a sound vibration performance,
It is excellent in efficacy and abrasion resistance and is industrially extremely suitable.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F16D 69/02 F16D 69/02 E // C08L 61:06 C08L 61:06 F term (reference) 3J058 BA21 FA01 FA11 FA21 GA03 GA04 GA07 GA14 GA20 GA23 GA24 GA29 GA33 GA34 GA43 GA45 GA73 4F071 AA01 AA10 AA41 AA56 AA74 AB03 AB06 AB08 AB12 AB18 AB23 AB24 AB30 AD01 AE12 AH07 DA04 DA05 DA10

Claims (4)

[Claims] 1. A friction material composition containing a fibrous substance, a binder and a friction modifier, wherein 10 to 50% by weight of a metal fiber whose surface is coated with one or more elastomers of butyl rubber, silicone rubber and fluorine rubber. % Friction material composition. 2. The friction material composition according to claim 1, wherein the amount of the elastomer is 2 to 15 parts by weight based on 100 parts by weight of the metal fiber. 3. The metal fiber is made of butyl rubber, silicone rubber,
A method for producing a friction material composition, comprising coating with at least one elastomer among fluororubbers, adding a material containing another fibrous substance, a binder and a friction modifier, and mixing. 4. A friction material formed by heating and pressing the friction material composition according to claim 1 or 2 or the friction material composition produced by the method according to claim 3.