JPS6178839A - Wet friction material - Google Patents

Abstract

PURPOSE:To provide a wet friction material which has excellent heat resistance and inhibits the temperature rise of opposing plates during friction, by impregnating a skeletal fiber having a thermoplastic resin-coated surface with an org. binder and curing the binder. CONSTITUTION:The surface of a skeletal fiber composed of a woven fabric or a nonwoven fabric of a fiber selected from phenolic resin fiber, polyacrylonitrile fiber which has been made infusible and non-metallic inorg. fiber, is coated with 0.1-2.5vol% of a thermoplastic resin (e.g. PVA) having a heat distortion temp. of 100 deg.C or below. The skeletal fiber is impregnated with an org. binder such as nitrile/phenolic resin or nitrile/epoxy resin,and the resin is cured. EFFECT:Handling in the high-viscosity matrix resin impregnation stage can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a wet friction material.Conventional technologyWet friction materials for construction machinery, etc., have a high energy absorption capacity as machines become larger. has been requested. Also, M
As friction disks become larger, achieving uniform contact with the mating plate and suppressing the occurrence of heat spots has become essential in order to increase the energy absorption ability of the disk as a whole.

To achieve this goal, the material must have low elasticity, and it is thought that organic materials are easier to implement than metal materials.
No. 8749), etc. have been developed, but organic materials generally have the disadvantage that they are inferior in heat resistance and thermal conductivity compared to metal materials. In addition, the practical disadvantage of organic materials is that lubricating oil t
decreases, even if only locally.

There is always a danger that this can quickly lead to major damage. The reason for this is as mentioned above.

This is mainly due to inferior heat resistance and thermal conductivity compared to Kinshiba materials. On the contrary.

(+) Jf- To provide self-lubricating properties to the vibration material itself.

Add a solid lubricant such as graphite or Mo52.

(2) Countermeasures such as increasing the porosity and making oil leaks less likely to occur can be considered, but first, solid lubricants have only a small effect when added in small amounts, and conversely, adding large amounts can greatly reduce the strength of the material. In particular, there is a problem in the transmission clutch of a bulldozer that there is a risk of material destruction during operation. Furthermore, regarding measures to increase the porosity, it is generally difficult to obtain a sufficient porosity with mold materials other than paper materials.

Background of the Invention or Basic Knowledge In view of the above circumstances, the present inventors have developed a wet friction material that has sufficient porosity and has excellent self-lubricating properties without adding a solid lubricant. Patent applications were filed earlier (Japanese Patent Application No. 57-209244, Japanese Patent Application No. 58-0129)
No. 66 and Percent Application No. 58-245272). That is,
These inventions were developed by the present inventors.

(1) organic fibers that do not melt at high temperatures and are easily carbonized, or (2) non-metallic inorganic fibers that have a high heat-resistant limit temperature as a backbone. These include a nitrile phenolic resin as a matrix and a copolymer of tril rubber and phenolic resin)
Alternatively, we provide a wet friction material with excellent heat resistance, which is obtained by impregnating nitrile epoxy resin with a highly heat-resistant organic binder such as a copolymer of tririle rubber and epoxy resin, and molding it under pressure and temperature. be.

In the process of manufacturing this friction material, felt-like non-woven fabric or paper-like sheets are used as the backbone fibers. Or we need to increase the rigidity of the paper-like sheet using some other method.

It was found that the handling property during the impregnation process was significantly reduced.

Therefore, in order to solve the above problem, the present inventors pinned and bonded the contact points of the fibers forming the skeleton.

We have developed a method to improve the handling properties in the process of impregnating high-viscosity polymeric resin by improving the rigidity of the felt or paper-like sheet, which is the fibrous material that serves as the skeleton. In other words, by appropriately coating the skeleton fibers with a thermosetting resin such as phenol or epoxy, the temperature of the mating plate will not rise too much. We succeeded in improving the handling properties when impregnated with matrix resin. However, the temperature of the mating plate is higher than that of conventional sintered alloy friction materials and graphite friction materials, and in this respect, there is still room for improvement.

Problems to be Solved by the Invention Therefore, an object of the present invention is to significantly suppress the rise in temperature of the mating plate during friction by further applying special treatment to the skeleton fibers, and to improve heat resistance and matrix resin impregnation as described above. The object of the present invention is to provide a wet friction material that has excellent handling properties in the process.

Means for Solving the Problems In order to achieve the above object, the wet type rubbing material according to the present invention is characterized in that the surface of the skeletal fibers is coated with a thermoplastic resin having a heat deformation temperature of 100°C or less. It is made by impregnating and hardening skeletal fibers that have undergone such special treatment with an organic binder as a matrix.

Effects and Modes of the Invention The friction material described in the series of inventions by the present inventors as described above has heat resistance because the matrix nitrile phenolic resin or nitrile epoxy resin carbonizes on the friction surface. Therefore, even if the temperature of the mating plate is somewhat high, the MW material itself is not easily damaged. However, if the temperature of the mating plate is too high, there is a risk that problems such as deformation of the mating plate and deterioration of the lubricating oil may occur.

As a result of extensive research, it has been revealed that, although this is completely different, if the skeleton fibers are coated with a thermoplastic resin having a low heat deformation temperature, the rise in the temperature of the mating plate can be significantly suppressed. Moreover.

No deterioration in performance as a friction shrine was observed.

The reason for this is not clearly elucidated at present, but qualitatively, the bonding force between the backbone fibers and the matrix resin, or the bonding force between fibers, is weakened by the thermoplastic resin. This is presumed to be because as a result, the surface pressure that the fibers press against the mating plate decreases, and the calorific value per unit decreases. Among the constituent members of the friction material of the present invention, the fibers that form the skeleton do not melt at high temperatures and are made of carbon. Organic fA! Fibers, or non-metallic inorganic lIR fibers with high heat resistance limit temperature metals 1 For example, it! (73, Scm,
Felt-like materials such as non-woven or woven fabrics made of ceramic fibers, glass fibers, carbon fibers, aramid fibers, etc., or paper-like sheets are suitable.

As a thermoplastic resin with a low heat distortion temperature, a heat distortion temperature of 1
Resin 1 below 00°C such as polyvinyl alcohol, polystyrene, low density polyethylene, A B S resin,
Suitable materials include A S resin, vinyl chloride, and pMM A resin. In order to coat the skeletal fibers with these resins, the fibers are impregnated with a low concentration solution of these resins, and the excess liquid is squeezed out.

The drying method is simple. Possible methods for squeezing the excess liquid include passing it between a pair of rolls and using centrifugal force.

The amount of thermoplastic resin coating on the skeletal fibers is 0.0 as a ratio to the volume of the skeletal fibers. t~2.5%, preferably 0.5~1.5%. If it is lower than 0.1 inch, it will not be effective in suppressing (reducing) the temperature rise of the mating plate, while if it is higher than 2.5 inch, the overall deformation of the friction material will be large during IF, and the friction material will become hard. This is undesirable because the Young's modulus increases and the mating plate is strongly rubbed, resulting in high strength.0 The organic binder used as the matrix must have high heat resistance, do not become brittle after curing, and have low elasticity. is suitable. Such heat-resistant resins include nitrile phenolics, copolymers of trilcomb and phenolic resins)
A heat-resistant adhesive such as a copolymer of nitrile rubber and epoxy resin (nitrile/epoxy resin) is most suitable, and sheaths such as fluororubber, acrylic rubber, etc. can also be used.

Furthermore, these binders come in the form of fine powders and particles! It is also possible to further improve the coefficient of friction and wear resistance by adding additives and solid lubricants.

In addition, 1 wet type 1'1 of the present invention. It is acceptable for trace amounts of impurities such as sand, oil, paint, etc. to be mixed into the vibration material, either by adhering to the component parts or by entering from the outside.

These impurities have almost no effect on the effect 1 of the friction material of the present invention.

Embodiment 1j The present invention will be specifically described below with reference to Examples.

Example 1 Felt of phenolic resin fiber (trade name Kynor, manufactured by Kynor Co., Ltd.) was used as the skeleton fiber, and 1% by weight of this was used.
The felt was soaked in a polyvinyl alcohol water bath solution, and the felt was squeezed with two rolls to remove excess solution so that the fR ratio of the coating resin to the fibers was 0.05 to 3.5%. This was dried at 80° C. for 2 hours, impregnated with nitrile phenolic resin having a solid content concentration of 45% by weight, and after drying, molded and adhered to a core plate, and subjected to a friction test. The results are shown in Table-1.

From the margin table-1 below, the volume ratio of coated grains/i-fat is 0.10 to 2.5
It can be seen that in the range H, the temperature of the mating plate is about 20 to 25°C lower than that of the 3.5% sample/161 and the 0.05% sample A3, and the above range is suitable. Also, the amount of resin on the plate is 3
．． In the case of 5% (sample No. 1), the amount of over-pressure plus the amount of settling of the friction material eye becomes significantly large, the friction material becomes hard due to plastic deformation, and the temperature of the mating plate also increases.

Example 2 Felt of phenolic resin fibers was used as the skeleton fiber, and this was immersed in a 1% by weight solution of various thermoplastic resins with a heat deformation temperature of 100°C or less, or thermosetting resins such as resol and epoxy. Excess solution is removed using two rolls so that the volume percentage of the resin is 1.0%, and this is impregnated with a nitrile epoxy resin with a solid content concentration of 45% by weight. After drying, it is molded and cored. Glue it to the board 1.
gA test.

The results are shown in Table-2.

From Table 2, in the case of the inventive material, the mating plateffl is higher than in the case of the comparative material. 'l It can be seen that the anal temperature drops by about 40 to 50 degrees Celsius.

The following are blank spaces.Example 3 The skeleton l height is a paper-like sheet of alumina/silica fiber, and it is made of various thermoplastic resins with a heat deformation temperature of 100°C or less, or thermosetting resins such as resol and epoxy.
Immersed in a wt% solution, the volume ratio of resin to fiber is 0.5
% by squeezing out the excess solution with two rolls, impregnating it with 30% by weight of nitrile phenolic resin, drying, molding, and adhering to the core plate.

It was subjected to a friction test. The results are shown in Table-3.

From Table 3, it can be seen that in the case of the present invention material, the temperature of the mating plate is lowered by about 35 to 55°C than in the case of the comparative material.

Below margin Effect of the invention As described above, the wet type L vibration material according to the present invention.

The surface of the skeletal fibers is coated with a thermoplastic resin with a heat deformation temperature of 100°C or less, and the skeletal fibers subjected to such treatment are impregnated with an organic binder as a matrix and cured. It has the unique effect of being able to significantly suppress the rise in temperature of the mating plate during Pfq, and is also highly praised for its heat resistance and non-linkability in the matrix resin impregnation process.

Claims (1)

[Scope of Claims] 1. A wet friction material obtained by impregnating and curing a skeleton fiber with an organic binder as a matrix, the surface of which is coated with a thermoplastic resin having a heat distortion temperature of 100° C. or lower. 2. Claim 1, wherein the skeleton fibers are phenolic resin fibers or infusible polyacrylonitrile fibers
Friction material described in section. 3. The friction material according to claim 1, wherein the skeleton fibers are non-metallic inorganic fibers. 4. The friction material according to claim 2 or 3, wherein the fibers serving as the skeleton are in the form of a felt-like nonwoven fabric or a paper-like sheet. 5. The friction material according to claim 1, wherein the volume ratio of the thermoplastic resin covering the skeleton fibers to the skeleton fibers is 0.1 to 2.5%. 6. The friction material according to claim 1, wherein the organic binder forming the matrix is a nitrile phenolic resin or a nitrile epoxy resin.