JPH11269279A - Manufacture of wet type friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a paper-base wet type friction material effectively and at a low cost while taking advantage (improvement of durability, etc.), of using a silane coupling agent, but requiring no special pretreatment to an inorg. material before papermaking and to a paper base material after papermaking. SOLUTION: This manufacturing method comprises a process in which a paper base material is made into paper using at least either one of an inorg. filler contg. silicon not treated with a silane, or a glass fiber not treated with a silane, and an org. fiber, and a process in which a paper-base friction material is obtd. by impregnating a thermosetting synthetic resin mixed with a silane coupling agent and setting, and the mixing dose of the silane coupling agent is 0.1-10 wt.% of the total of the friction material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet friction material suitable for a wet friction engagement device, for example, a wet friction clutch or a friction brake.

[0002]

2. Description of the Related Art In producing the above-mentioned wet friction material, organic fibers such as cellulose fibers are used as organic materials, and inorganic fibers such as glass fibers are used as inorganic materials.
Or, after making a paper base material using an inorganic filler such as diatomaceous earth, the paper base material is impregnated with a binder such as a thermosetting synthetic resin (mainly a phenol resin) and cured to obtain a paper-based wet friction. Conventionally, a technique for obtaining a material has been proposed, and it is known that a wet friction material manufactured in this manner exhibits stable friction characteristics (for example, a friction coefficient) with respect to temperature, pressure, and rotation speed. Have been.

Further, in order to increase the mechanical strength of such a paper-based wet friction material, and to improve its heat resistance and durability, for example, Japanese Patent Publication No. Hei 5-34530, Japanese Unexamined Patent Publication No. Hei.
As disclosed in JP-A-79079 and JP-B-2-39653, a silane coupling agent is used as a surface treatment agent for an inorganic filler and glass fiber in a paper base material, and the glass fiber and the like are combined with a resin. Techniques for improving the connectivity have already been proposed.

[0004]

In the above proposal,
A coupling treatment (so-called silane treatment) using a silane coupling agent is specially applied to an inorganic material (for example, an inorganic filler or glass fiber) before the papermaking process or a paper base material after the papermaking process. Therefore, the pretreatment step complicates the manufacturing process of the friction material, causing a reduction in production efficiency and an increase in cost.

[0005] The present invention has been made in view of such circumstances, and while taking advantage of the use of a silane coupling agent (improvement in durability and the like), it is possible to use an inorganic material or a papermaking process prior to the papermaking process. It is an object of the present invention to provide a method for producing a wet friction material which solves the above-mentioned problems of the conventional method by eliminating the need for performing a special pre-treatment on the paper substrate afterward.

[0006]

In order to achieve the above object, a method for producing a wet friction material according to the present invention comprises the steps of: providing at least one of a silicon-containing inorganic filler which is not silane-treated and a glass fiber which is also not silane-treated; And a step of paper-making a paper base using organic fibers, and a step of impregnating the paper base with a thermosetting synthetic resin mixed with a silane coupling agent and curing to obtain a paper-based friction material. Comprising, the mixing amount of the silane coupling agent,
It is characterized by being 0.1 to 10% by weight of the whole friction material.

In the present invention, the term "silane coupling agent" refers to an organic material (for example, synthetic resin) and an inorganic material (for example, glass fiber, inorganic filler) having the property of chemically bonding both materials. The term "silane treatment" refers to a surface treatment applied to a base material using a silane coupling agent to improve the bondability.

[0008]

[Function] Generally, a silane coupling agent has two kinds of reactive groups (for example, an alkoxysilyl group and an organic reactive functional group) at both ends, and among them, an organic reactive functional group (for example, an epoxy ring) Reacts with a thermosetting synthetic resin to form a chemical bond such as an ether bond. On the other hand, the alkoxysilyl group hydrolyzes to a silanol group due to the presence of water, or undergoes dehydration-condensation or dealcoholization-condensation with a silanol hydroxyl group on the surface of the glass fiber or silica to form a chemical bond. As a result, a strong bond is formed between at least one of the inorganic filler and the glass fiber, the thermosetting synthetic resin, and the silane coupling agent. And at least one of the glass fibers and the thermosetting synthetic resin enhances the bonding and adhesiveness), thereby increasing the mechanical strength of the friction material as a whole, reducing the amount of wear, improving durability, and improving heat resistance. It is planned.

In addition, the silane coupling agent is mixed with the thermosetting synthetic resin, and the resin after the mixing is impregnated and cured in the paper base material. For example, there is no need to perform a coupling treatment (silane treatment) and other special pretreatments on the glass fiber and / or silicon-containing inorganic filler) and the paper substrate after the papermaking process.

[0010] The mixing amount of the silane coupling agent is 0.1.
When the amount is less than 1% by weight, the effect of adding the silane coupling agent is not sufficiently exhibited. On the other hand, when the amount of the silane coupling agent is more than 10% by weight, the friction characteristics originally possessed by the friction material are large. Will change.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on embodiments of the present invention illustrated in the accompanying drawings.

In the accompanying drawings, FIG. 1 is an overall perspective view showing an embodiment of a friction plate, FIG. 2 is a longitudinal sectional view of the embodiment, and FIG. 3 is a graph showing the relationship between the amount of silane coupling agent added and the amount of wear. FIG. 4 is a graph showing a torque waveform (Example 3) using a SAE # 2 test machine, and FIG. 5 is a graph showing a torque waveform (Comparative Example 1) using a SAE # 2 test machine.

First, in FIGS. 1 and 2, a friction plate (clutch disc D) for a wet friction clutch is used.
Is composed of an annular core 1 and an annular wet friction material 2 which is polymerized and bonded to both surfaces of the core 1. The friction material of the present invention is used as the wet friction material 2, and an oil groove 2 a is formed on the surface of each friction material 2 as necessary.

In producing the friction plate, first, an organic fiber such as a cellulose fiber as a raw material of a paper base, an inorganic fiber such as a glass fiber, and a silicon-containing inorganic filler such as diatomaceous earth are mixed at a predetermined ratio. Then, this is subjected to papermaking by a conventionally known wet papermaking method (that is, ordinary papermaking work) to prepare a paper base material. In this case, the glass fiber and the inorganic filler used are those that have not been subjected to silane treatment, that is, those that have not yet been subjected to coupling treatment (surface treatment) with a silane coupling agent.

Next, the above-mentioned paper base material is impregnated with a predetermined amount of a thermosetting synthetic resin such as a phenolic resin, and then cured by heating or naturally drying to produce a friction material 2. A friction plate is obtained by forming into a predetermined shape by punching or the like and polymerizing and fixing (adhering) to both surfaces of the cored bar 1. Instead of fixing the cured friction material 2 to the metal core 1 as described above, an uncured relatively soft friction material intermediate is superimposed on the metal core 1 and pressed by a pressing die or the like. May be completely cured (accordingly, fixed to the core metal 1).

Next, a specific embodiment of the present invention will be described. In this example, a paper base having the basic composition shown in Table 1 below is prepared by a conventional wet papermaking method. Next, a phenolic thermosetting synthetic resin material premixed with the silane coupling agent in weight% shown in Table 1 is impregnated and cured into the paper base material that has not been subjected to silane treatment, and a friction material having a predetermined shape is obtained. A friction plate was obtained by molding, and the friction material was polymerized and adhered to both sides of the cored bar.

[0017]

[Table 1]

Further, a friction plate was obtained in the same manner as in the example, except that the composition of the paper substrate was the same as that of the example and no silane coupling agent was added.

The friction plates obtained in the above-described embodiments and comparative examples are mounted on a conventionally known inertial absorption type clutch full size tester, and the inertial body (flywheel) of the tester is rotated at a predetermined rotational speed. After the rotation of the friction plate, the inertia body was driven by stopping and engaging the clutch to perform the measurement, and when such operation was repeated a predetermined number of times, the wear amount of the friction plate was measured. In the illustrated example, the input rotation speed of the inertial body is 3000 rpm and the test oil (ATF) is Dex.
tron II, the predetermined number of times is set to 500 times.

FIG. 3 shows the amount of wear of the friction plates according to Examples 1 to 3 and Comparative Example 1. According to this graph, it is clear that the wear amount of the friction plate decreases as the addition amount of the silane coupling agent increases, and the wear resistance of the friction plate improves due to the effect of the addition of the silane coupling agent. It turns out that there is. Although not shown as specific data, the effect of the addition of the silane coupling agent in the above-described embodiment was determined by the effect of the silane coupling agent on inorganic materials before the papermaking process and on the paper base material after the papermaking process as in the prior art. Experiments have confirmed that the effect of adding the silane coupling agent is not inferior to the effect of the treatment.

The friction characteristics of the friction plates according to the examples and comparative examples were measured using a SAE # 2 tester. In the illustrated example, the input rotation speed of the inertial body is 3000 rpm, and the test oil (ATF) is Dextro.
nII.

FIG. 4 shows the friction characteristics of the friction plate according to the third embodiment in the form of a torque waveform (μ-rotational speed). FIG. 5 also shows the friction characteristics of the friction plate according to Comparative Example 1 by a torque waveform (μ-rotation speed). From the comparison of these graphs, it is clear that even when the silane coupling agent is added, there is no significant change in the torque waveform, and the torque value shows a stable torque value with respect to the rotation speed.
In the graphs of FIGS. 4 and 5, the dotted lines indicate the change values of the torque and the rotation speed after the endurance test of the predetermined number of times is completed.

The embodiment of the present invention has been described above.
The present invention is not limited to the above embodiments, and various small design changes are possible within the scope of the invention. For example, in the above embodiment, a clutch disk for a wet friction clutch was shown as a friction plate using a wet friction material.
The present invention is also applicable to various wet friction engagement devices other than the clutch, for example, a friction plate for a friction brake.

In the above embodiment, the phenol resin is used as the thermosetting synthetic resin. However, other thermosetting synthetic resins such as epoxy resin and melamine resin may be used.

[0025]

As described above, according to the present invention, by adding a silane coupling agent to a paper-based wet friction material, at least one of a glass fiber and an inorganic filler, a thermosetting synthetic resin, Since a strong bond is generated between the three members with the silane coupling material, the mechanical strength of the friction material as a whole increases, reducing the amount of wear and durability,
There are advantages such as that it can contribute to improvement in heat resistance.

In addition, the silane coupling agent is mixed with the thermosetting synthetic resin, and the resin after the mixing is impregnated into the paper base and cured. It is not necessary to perform special pretreatment such as coupling treatment (silane treatment) on the paper base material after the papermaking process, such as glass fiber and / or silicon-containing inorganic filler, and therefore, the addition of a silane coupling agent While omitting the inherent advantage of the above, the friction material can be manufactured efficiently and at low cost by omitting the special pretreatment step.

Further, since the mixing amount of the silane coupling agent is 0.1 to 10% by weight based on the whole friction material, the desired effect of the addition of the silane coupling agent is sufficiently ensured, and the friction material has an original effect. Friction characteristics can be minimized from being affected by the addition of the silane coupling agent. Therefore, the friction material of the present invention has a stable torque value with respect to the number of rotations, temperature, and pressure even by the addition of the silane coupling agent, and is effective in reducing judder vibration and the like.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing an embodiment of a friction plate.

FIG. 2 is a longitudinal sectional view of the embodiment.

FIG. 3 is a graph showing the relationship between the amount of silane coupling agent added and the amount of wear.

FIG. 4 is a graph showing a torque waveform (Example 3) by a SAE # 2 tester.

FIG. 5 is a graph showing a torque waveform (Comparative Example 1) by a SAE # 2 test machine.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI B29K 101: 10 B29L 31:16 C08L 61:04 (72) Inventor Tomohiro Hasegawa 46 shares of 7000 Nakagawa, Hosoe-cho, Husa-gun, Shizuoka Prefecture FCC Technology Research Institute

Claims (1)

[Claims] 1. A paper-making process using at least one of an unsilane-treated silicon-containing inorganic filler and a non-silane-treated glass fiber and an organic fiber. Impregnating and curing a thermosetting synthetic resin mixed with a silane coupling agent to obtain a paper-based friction material, wherein the mixing amount of the silane coupling agent is 0.1 to A method for producing a wet friction material, characterized in that the content is 10% by weight.