JPS638974B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to friction materials used in vehicles, etc., particularly brake pads, brake linings, etc., and more specifically, to friction materials based on iron fibers. This invention relates to a friction material with improved rust effect. [Conventional technology] As a conventional technology, these friction materials are
As disclosed in No. 52448, the fibrous reinforcing agent is made of asbestos fiber as a base material, which is mixed with a thermosetting binder, various fillers, friction improving materials, etc., and then thermoformed. Mold type was the mainstream. From a medical perspective, products manufactured using asbestos fibers such as clutch discs, brake pads, brake linings, etc., which are manufactured using asbestos fibers as mentioned above, can cause serious damage to the human lungs of workers who handle asbestos fibers during the production process. Proven. This is due to the fact that fine particles are scattered on the asbestos single fibers during mixing, kneading, molding, etc. of the material components in the manufacturing process, causing environmental pollution within the factory. Therefore, there is a particular need to eliminate the use of asbestos fibers and use alternative fibers as the base material. Among these, iron-based fibers are relatively easily available and inexpensive, as disclosed in JP-A-54-80352, and are therefore easily used. [Problems to be Solved by the Invention] However, in this friction material based on iron-based fibers, the iron-based fibers are exposed to the sliding surface during long periods of stopping after braking, and moisture is generated due to cooling. Moisture absorption causes oxidative corrosion and rust. The rust that adheres to the sliding surface of this friction brake body has the tendency to rust on the mating material, and because the rust of the friction material has poor thermal conductivity, there are drawbacks such as a sudden drop in the coefficient of friction at high temperatures. . As a method of preventing rust, which is a disadvantage of these products, it is well known to apply anti-rust treatments to iron-based fibers, such as bonderite, phosphoric acid coating, zinc plating, etc. However, zinc plating increases the cost of the fiber itself and is difficult to implement. [Means for Solving the Problems] The inventors of the present invention have taken many measures to improve the above-mentioned drawbacks, and as a result, the present inventors have developed a method using thermosetting binders, iron-based fibers, and other fillers and additives. In friction materials containing 1 phenol resin per 100 parts by weight of iron fibers.
~10 parts by weight (NV) is coated on the surface of the fiber in advance, and 1 to 15 parts by weight of zinc powder, which has a higher ionization tendency than iron, is attached to the iron-based fiber, and then air-dried or cured. It was discovered that an asbestos-free friction material containing iron-based fibers as a base material is effective. NV is an abbreviation for non-volatile. To be more specific, the iron-based fibers that will serve as the base material are first sieved and then coated with phenol resin, which is a thermosetting resin, and accelerated drying. This method uses an iron-based friction material obtained by attaching zinc powder, which has a higher ionization tendency than the conventional method, to a resin on the surface of fibers and then curing it. [Operation of the invention] A friction material completed using a base material of iron-based fibers that has undergone such resin coating and surface treatment processes reduces the degree to which the iron-based fibers come into direct contact with moisture. , thus making it difficult for iron to undergo oxidation corrosion. Furthermore, by attaching zinc powder, which has a greater ionization tendency than iron, to the surface of the iron-based fibers, oxidation caused by ionization of the iron-based fibers is prevented, and corrosion is prevented. [Example] Hereinafter, a detailed explanation will be given according to an example.

[Table] The above drying conditions are curing and drying at 135°C for 60 minutes. The substrate treated with the above formulation is used to produce the following formulation.

[Table] Products of Example 1 and Example 2 were manufactured using the processed iron-based fibers shown in Table 1 above and the manufacturing formulations shown in Table 2, respectively. In addition, as a comparison, ordinary iron-based fibers (untreated) were used in Comparative Example 1.
was manufactured. In order to examine the rusting properties when the friction material and the disc (counterpart material) come into contact using these products, the friction surface of the disc was sufficiently degreased with methanol as a solvent in advance, and then the friction material was tested as shown in the figure below. Overlapping the friction surface 2a of the friction material 2 on the friction surface 1a of the disk 1,
After standing for 120 hours at a temperature of 20℃ and humidity of 80%,
The force required for tensile peeling was measured using a spring balance 3 in the direction of the arrow shown in the first figure. As a result, the force required for the tensile peeling was 3.1 g/cm ² for the friction material obtained in Example 1, 2.7 g/cm 2 for Example 2, and 15.0 g/cm ² for Comparative Example 1.
g/ ^cm2 . In addition, the friction materials obtained in Example 1 and Example 2 showed very slight rust formation on the friction surface after the rust resistance test, but on the other hand, the friction materials obtained in Comparative Example 1 did not develop rust. Significant rust was observed. [Effects of the Invention] As is clear from the above rust resistance test, the friction material using the treated iron fiber of the present invention has a higher resistance to the force required for tensile peeling (the rust resistance between the friction material and the mating material) than the conventional products. We offer a friction material that has a small sticking force (approximately 1/5), has excellent rust resistance during long periods of stoppage, and is less prone to rusting.

[Brief explanation of the drawing]

The figure shows an evaluation test method for comparing the rust adhesion properties of the friction material of the present invention and conventional friction materials.

Claims (1)

[Claims] 1. In friction materials containing thermosetting binders, iron-based fibers, and other fillers and additives, iron-based fibers
The fiber surface is coated in advance with 1 to 10 parts by weight (NV) of phenolic resin per 100 parts by weight, and 1 to 15 parts by weight of zinc powder, which has a higher ionization tendency than iron, is adhered to the iron fiber. An asbestos-free friction material characterized by containing iron-based fibers obtained by post-air drying or curing as a base material.