JPH0545807B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) When the present invention is used in so-called wet clutches and brakes in which an appropriate lubricating oil is interposed between opposing friction surfaces, it has a higher load-bearing capacity than conventional materials. It also has a high coefficient of friction, low wear of the friction material and the mating material, sufficient mechanical strength to withstand mechanical effects that occur during friction such as chipping and peeling, and a high resistance to sliding speed, surface pressure, temperature, and oil resistance. This invention relates to a friction material that uses thermosetting resin and rubber as binders and has various properties that are stable against changes in usage conditions such as oil content and oil type. (Prior Art) Sintered alloy friction materials having a matrix of copper alloys have been used as wet high-load friction materials. In addition to the heat resistance of the material itself, this
It also has good thermal conductivity, has excellent seizure resistance, is less affected by thermal history and has a certain degree of capacity against abnormalities such as sudden oil loss, and is made of organic material for bonding with the back plate. Due to the use of metal bonding instead of adhesives,
This is because it has high reliability at high temperatures and high loads. However, as machines have become larger in recent years, friction plates have also become larger, and a situation has arisen in which the advantages of sintered metal materials cannot be fully utilized under some usage conditions. It is generally said that sintered metal materials have an elastic modulus of 100
Kg/mm ² or more, which is relatively high, and therefore, in the case of large diameter, wide, and large area friction plates, local contact with the mating material occurs, and the area receives intensive heat load, resulting in a seizure limit. If the sintered metal material is heat resistant and has excellent seizure resistance, even if it is designed to have sufficient load capacity per unit area, it may not achieve the purpose. This is because you may not be able to obtain it. Therefore, for large, wide, and large-area objects, we use materials that use thermosetting resin as a binder and add rubber components to this to give elasticity, such as Japanese Patent Publication No. 57-2733, or various types of rubber. Some materials have been proposed, such as JP-A-51-87649, which use sintered metal as a binder, and some materials have even emerged that exceed sintered metals in terms of seizure resistance under certain conditions. . However, materials containing these various elastomers that have been proposed and put on the market are unable to maintain their initial characteristic values or deteriorate rapidly after long-term use due to the low heat resistance and lack of oil resistance of the elastomers themselves. In many cases, this resulted in increased wear. In order to improve this drawback of elastomer-containing materials, it has been proposed to use carboxy-modified nitrile rubber as the elastomer and epoxy resin as the binder, but this method involves chemically reacting carboxyl groups and epoxy groups. The aim was to firmly bind the rubber and resin binder through covalent bonds, thereby improving strength, oil resistance, heat resistance, durability, and seizure resistance, abrasion resistance, etc. Although this method was very effective as a method of adding rubber to impart elasticity, it still lacks in terms of seizure resistance, abrasion resistance under medium and high loads, and the tendency for the coefficient of friction to decrease under high surface pressure. It wasn't enough. (Problems to be Solved by the Invention) An object of the present invention is to improve the above-mentioned drawbacks of conventional elastomer-containing wet friction materials and to obtain an excellent elastomer-containing wet friction material. (Means for Solving the Problems) The present invention provides a wet friction material in which an epoxy resin is used as a resin binder, and a reactive elastomer and a friction filler are added to impart elasticity to the epoxy resin. As a curing agent for the resin, an appropriate amount of polyparahydroxystyrene, phenolic resin, phenol/aralkyl resin, acid anhydride, or a mixture of two or more of these (hereinafter referred to as polyparahydroxystyrene, etc.) is used, This improves the above drawbacks. (Function) In other words, as shown in Japanese Patent Publication No. 57-2733, curing agents for epoxy resins conventionally used in friction materials include Lewis bases, inorganic bases, primary and secondary amines, and amides. For example, in contrast to dicyandiamide, polyparahydroxystyrene, which has significantly improved heat resistance, is used. By this, for example, when the reactive rubber is a carboxy-modified acrylonitrile rubber, the carboxyl groups of the rubber and the epoxy groups of the resin are reacted, and in this case, the epoxy groups are completely crosslinked with respect to the epoxy groups present in considerable excess. By curing with an appropriate amount of polyparahydroxystyrene, etc., rubber, epoxy resin, polyparahydroxystyrene resin, etc. are firmly bonded by covalent bonds, improving heat resistance, oil resistance, and durability. , seizure resistance, wear resistance under high loads, stability of friction coefficient over time, pressure stability, etc. have been dramatically improved. The composition range of the components specified in the claims is such that if any component falls outside this range, the various properties of the friction material such as friction coefficient, wear resistance, strength, seizure resistance, oil resistance, durability, etc. This will cause some inconvenience. (Example) Examples of the present invention will be described below. This example is an example of an experiment conducted to confirm the effect of the invention and confirm the scope of application, and the scope of claims is not limited by the example.

【table】

[Table] Unit is weight%. In addition to the above, anti-aging agents,
Curing accelerator, etc., 0.1% by weight in each example (external)
Added. Example 1 The formulation shown in Table 1 was kneaded using a roll or kneader until each component was uniformly dispersed,
I put it on a calendar and made it into a sheet. The sheet was cut into a desired shape, heat-cured, bonded to a steel core plate material, and an oil groove was cut to form a test sample. The elastic modulus of this material is approximately 50Kg/mm ² and the hardness is 75 for Rockwell 15Y, and when comparing its friction properties with other materials, it has a much higher load capacity, less wear, and the use of a friction coefficient It was highly durable and had excellent oil resistance with little variation due to conditions. For example, friction plate size 194φ x 164φ, 1 plate 2 sides,
Absorbed energy 20Kg・m/cm ² , moment of inertia
0.183Kg・m・sec ² , clutch frequency 30sec/cycle,
When the lubricating oil is SAE standard engine oil 10W, the oil volume is 8 c.c./cm ² min, and the supplied oil temperature is 80°C, the limit average absorbed energy is 40 Kg m/cm ² sec or more.
The wear amount at this point for 100 cycles was 0.03 mm. In addition, the absorbed energy is 10Kg・m/cm ² , the moment of inertia is 0.136Kg・m・sec ² , and the frequency is 17sec/
cycle, oil type 10W, oil amount ^8c.c./cm2・min, oil temperature 80
°C, pressure 15Kg/cm ² , average absorbed energy 15Kg・
In the durability test at m/cm ² sec, the coefficient of kinetic friction
0.12, static friction coefficient 0.15, no decrease in friction coefficient was observed, and the steady wear rate was 0.05×10 ^-7 cm ³ /
It was small, less than Kg・m. Examples 2 to 5 Samples were produced in the same manner as in Example 1, and the same tests were conducted. The test results were almost the same as in Example 1. (Effects of the Invention) When the present invention is used in wet clutches and brakes, it has a higher load-bearing capacity compared to conventional materials, has a higher friction coefficient, and has less wear on the friction material and the mating material. It has sufficient mechanical strength to withstand the mechanical effects that occur during friction, such as chipping, peeling, etc., and has stable properties against changes in operating conditions such as sliding speed, surface pressure, temperature, oil amount, and oil type. The present invention has great industrial value because it provides a friction material having the following characteristics.

Claims (1)

[Claims] 1. Epoxy resin 5 to 30%, rubber for imparting elasticity etc. to the material 30 to 40%, and friction filler 30 to 30% by weight relative to the entire material (all percentages are expressed below). In wet friction materials made of 92%, the rubber added to impart elasticity to the material is carboxy-modified acrylonitrile-butadiene rubber that is reactive with epoxy resins or epoxy-modified acrylic rubber that is reactive with curing agents. The curing agent used is one or more selected from polyparahydroxystyrene, phenolic resin, phenol/aralkyl resin, and acid anhydride in an appropriate amount sufficient to completely crosslink the epoxy group. A wet friction material comprising a mixture. 2. In the wet friction material according to claim 1, the friction filling material is composed of the following components (A) to (D) in weight ratio to the entire material (A) graphite, molybdenum disulfide, lead, etc., which are known as friction materials. Lubricating ingredients 70% or less (B) Friction materials with a Mohs hardness of 4 or higher, 30% or less mineral substances called hard particles (C) Friction adjustment agents known as friction materials such as barium sulfate, calcium carbonate, magnesium carbonate, cashew dust, etc. Substances 25% or less (D) Pulp fiber, carbon fiber, aromatic polyamide fiber, phenol fiber, silica-alumina fiber,
Wet friction materials that are one type or a mixture of two or more types of organic, inorganic, or metal fibers or whiskers, such as glass fibers, copper and copper alloy fibers, iron and iron alloy fibers, and silicon carbide whiskers, containing up to 80%. 3. The wet friction material according to claim 1, wherein the epoxy resin is a so-called epibis type epoxy resin obtained by reacting bisphenol A and epichlorohydrin. 4. The wet friction material according to claim 1, wherein the epoxy resin is a phenol (or cresol) novolak type epoxy resin. 5. The wet friction material according to claim 1, wherein the epoxy resin is an alicyclic epoxy resin. 6. The wet friction material according to claim 1, wherein the epoxy resin is a polyfunctional glycidylamine type epoxy resin. 7 In the wet friction material of claim 1, the epoxy resin is a so-called epibis type epoxy resin obtained by reacting bisphenol A and epichlorohydrin, a phenol (or cresol) novolac type epoxy resin, an alicyclic epoxy resin. , a wet friction material comprising a mixture of two or more types of polyfunctional glycidylamine type epoxy resins.