JPS6020935A - Production of friction material - Google Patents

Abstract

PURPOSE:To prevent scattering, dusting, separation, segregation, etc., of powder, by mixing a mixture of materials for the production of a friction material with liquid substances of different boiling points, and evaporating the lower-boiling liquid substance. CONSTITUTION:In producing a friction material by mixing a powdered theremosetting resin with a reinforcing fiber, an organic or inorganic filler, a metallic powder, a friction modifier, etc., and curing the mixture by heating; a liquid mixture formed by dissolving a liquid substance of a b.p. >=200 deg.C (e.g., nonionic polyoxyethylene phenyl ether) in a liquid substance being incompatible with the powdered thermoplastic resin and having a b.p. <=100 deg.C (e.g., trifluorotrichloroethane) is added to the powder material and uniformly dispersed therein. The liquid substance of a b.p. <=100 deg.C is vaporized. It is possible to produce a friction material of stable quality without adversely affecting its fluidity as a powder, while the dusting, separation and segregation of the mixture can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing friction materials used in drum brakes and disc brakes.

The friction materials used in drum brakes and disc brakes are made of fibrous materials such as asbestos, metal fibers, and ceramic fibers, fillers such as barium sulfate, and friction modifiers such as graphite, alumino, and cashew dust, such as phenolic resins. It is manufactured by mixing with a thermosetting resin binder and then hot pressing.

The 71-nol resin used in this case may be in liquid or powder form. Powdered phenolic resins have become popular in recent years because they are easy to handle and can easily be obtained with high heat resistance.

As for the method of mixing powdered phenolic resin, powdered light modifier, friction modifier, and fiber material, the dry mixing method that does not use a solvent is used because it does not generate volatile substances. It is considered to be a simple method.

However, this method has the disadvantage that the resulting mixture tends to be powdery and that powders with different ratios W are separated and segregated.

It is common sense to keep the mixture moist in order to prevent this separation and segregation of powder, but when using liquid resin for this purpose or dissolving the resin in a solvent, it is harmful to the human body. There is a risk of ignition or fire due to the generation of volatile substances or the evaporated solvent.

Further, the mixture loses its fluidity as a powder due to solidification or agglomeration due to an increase in viscosity due to evaporation of the solvent, so re-grinding or the like is necessary.

In view of the above points, the present inventors applied d3 to the production of friction materials.
The present invention was developed as a result of various tests conducted to prevent dusting and separation of mixtures of reinforcing fibers, fillers, etc., and powdered thermosetting resins.

That is, this invention utilizes reinforcing fibers, organic fillers, inorganic fillers,
When heating and curing a mixture of a powdered thermosetting resin and metal powder J5, a friction chamber adjustment agent, etc. to obtain a thickness 1 abrasive material, substantially all of the powdered thermosetting resin and the like are heated and cured. Liquid substances with no compatibility and a boiling point of 100°C or higher have a boiling point of 20°C
This is a method for producing a friction material, which comprises adding a mixture in which a liquid substance having a temperature of 0°C or higher is dissolved to the above-mentioned mixed formulation, and then evaporating and drying the liquid substance having a boiling point of 100°C or lower.

The main point of this invention is to keep the powder raw material in a slightly moist state in order to prevent lumps a3 and separation and segregation. However, the temperature of general press molding is 140~
Moistening with a liquid substance having a boiling point lower than 180°C is undesirable as it may cause gas blistering during pressing, so in this invention a liquid substance having a boiling point of 200°C or higher is used.

In addition, the amount of the liquid substance with a boiling point of 200°C or higher used for moistening the powder raw material is preferably a very small amount, since too much will cause the powder to become sticky and impair the properties of the powder. 0.1 to 0.1 of the total body weight
10,000 m% is appropriate.

However, it is very difficult to add such a small amount of liquid substance to a large amount of powder raw material and to uniformly disperse C.

Therefore, a liquid mixture of a liquid substance with a boiling point of 200°C or higher dissolved in another liquid substance (solvent) with a boiling point of 100°C or lower is added to the powder raw material and uniformly dispersed in the raw material. be.

The liquid substance (i8 agent) with a boiling point of 100°C or less is
It can be removed by volatilization after dispersion.

Liquid substance (solvent) with a boiling point of 100℃ or less used in this case
-C is a powder raw material and must be substantially incompatible with the powdered thermosetting resin used.

This is because when a liquid substance (solvent) is used to dissolve the powdered thermosetting resin, the low boiling point solvent in the dissolved resin solution is released during the mixing process, and the viscosity of the solution itself is reduced. This is because the upper bound causes the powder to aggregate or agglomerate into lumps, making it impossible to obtain a friction material 1 having good powder characteristics.

The present invention is capable of preventing dust formation and segregation of the 115 compound without impairing the fluidity of the body, thereby producing a friction material with stable quality. It is possible.

However, the method for manufacturing the friction material of this invention is based on asbestos,
Metal fibers, heat-resistant materials (J-nolaramid, fibers, etc.) are mixed with a powdered thermosetting resin binder and other powder raw materials, and the mixture is thermoformed. It can be applied to the manufacturing method of thick-edged materials.

In the present invention, as the liquid substance (solvent) having a boiling point of + o o'c or less, it is preferable to use a nonflammable substance such as a fluorochlorinated carbon compound (for example, trifluorotrichloride ethylene).

The liquid substances having a boiling point of 200 DEG C. or higher are preferably nonionic polyoxyethylene nonylph]-nornefur, dialkyl succinic acid sulfonates, and the like.

This invention will be explained below with reference to Examples.

Examples Asbestos 40 Width% Phenolic resin 10 Baryta 18 Graphite 7 Cashew dust 10 Weight 0% Copper powder 15 Shaved 100 Ethylene trifluoride 100 c
Add a liquid substance in which polyoxyethylene nonylphenol derivatives are dissolved to c, mix well, and heat to 80°C.
When ethylene trifluoride trichloride was evaporated, it turned into a mixture containing only powder raw materials with the same composition as above, and the scattering, clumping, separation, etc. of the powder were significantly improved, and the FM
A mixture in a good mixed state can be obtained as the I material,
The II abrasion resistance was also almost the same as that of a mixture containing only powder raw materials.

Patent applicant: Sumitomo Electric Industries, Ltd. Representative Patent Attorney Kazu [Ro]

Claims (2)

[Claims] (1) A friction material formed by heating and curing a mixture of reinforcing fibers, organic fillers, inorganic fillers, metal powders, friction modifiers, etc. and a powdered thermosetting resin, in which substantially all of the above-mentioned A mixture in which a liquid substance with a boiling point of 200°C or higher is dissolved in a liquid substance that is incompatible with the powdered thermosetting resin and has a boiling point of 100°C or lower is added to the above-mentioned mixed formulation, and then the boiling point is 100°C or lower. A method for manufacturing a friction material, characterized by volatilizing and drying a liquid substance. (2) The method for producing a friction material according to claim 1, wherein the liquid substance having a boiling point of 200'C or higher accounts for 0.1 to 10% by weight of the total composition.