JPH03140334A - Wet friction material - Google Patents

Abstract

PURPOSE:To obtain a wet friction material having excellent kinetic friction coefficient, exhibiting good durability and muo/mud ratio even under high load condition and useful as an automobile clutch, etc., by using a thermosetting resin having a foamed structure with a specific open cell ratio. CONSTITUTION:The objective friction material is produced by compounding (A) a thermosetting resin (preferably phenolic resin, etc.), (B) a surfactant such as an alkoxysilane, (C) a foaming agent such as sodium carbonate and, as necessary, a friction-controlling agent (e.g. graphite), glass fiber, etc., in a state to give a foamed structure having a total pore ratio of 10-50% and an open cell ratio of 20-70% and containing cells having diameter of 5-200mum accounting for >=75% of the total cells [compounding 100 pts.wt. of the component A with 0.5-30 pts. wt. of the component B and 1-20 pts.wt. of the component c], uniformly kneading the mixture with a kneader, etc., foaming and curing the kneaded mixture in a hot atmosphere, forming in the form of a ring, etc., and bonding to a core plate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wet clutch in a vehicle automatic transmission and a synchronizer ring in a manual transmission.

It is used as a wet friction material useful for wet multi-plate clutch discs for motorcycles, wet brakes, etc.

[Prior Art] Until now, so-called paper friction materials based on paper have been mainly used as wet friction materials. Paper friction materials are manufactured by blending various friction modifiers and the like into a valve, then making paper, and then impregnating and curing the paper with a binding resin such as phenol resin. This paper friction material has a high friction coefficient and a good ratio of the final friction coefficient to the dynamic friction coefficient (hereinafter referred to as μO/μd ratio).

However, paper friction materials are no longer able to cope with the problem of a decrease in the coefficient of dynamic friction after long-term use under the conditions of increased engine output and increased vehicle weight, which increases the load on wet friction materials. ing. Wet friction materials such as sintered alloy, semi-metallic, and elastomer materials have been proposed to improve this, but these have the disadvantages of low dynamic friction coefficients and inferior μ0/μd ratios, and are still unsatisfactory. I can't find anything up to that level. Therefore, there is a strong desire to develop a wet friction material that can handle increased loads and has a high dynamic R friction coefficient and a good μ0/μd ratio.

[Problems to be Solved by the Invention] Therefore, as a result of intensive research to improve the above-mentioned drawbacks, the present inventors used a thermosetting resin having a foam structure with a specific open porosity as a friction base material. It has been discovered that by doing so, it is possible to obtain a wet friction material that has a high coefficient of dynamic friction and a good μO/μd ratio, and can sufficiently cope with increased loads, and has arrived at the present invention.

[Means for Solving the Problems] That is, in the present invention, continuous pores in the a raw base material account for 20 to 75% of the total pores, preferably 75% of the total pores.
A wet method characterized by using a thermosetting resin with a foam structure of 5 to 200 μm! I provide scraped timber. Another object of the present invention is to provide a wet friction material in which this friction base material is filled with an inorganic/organic friction modifier and fibers.

[Function] In the present invention, by using a thermosetting resin with excellent mechanical strength and heat resistance as the friction base material, it can be used for a long period of time even under high load conditions, and the structure can be adjusted to a specific ratio. It is estimated that the foamed structure provides optimal flexibility and quick diffusion of frictional heat, as well as a high dynamic R friction coefficient and a good μO/μd ratio. In order to obtain a smooth foamed structure, the friction base material in the present invention is obtained by foaming and curing a composition consisting of a thermosetting resin, a surfactant, a foaming agent, and, if necessary, a friction modifier and fibers. .

Thermosetting resins used in the present invention include phenolic resins, modified phenolic resins modified with oil, rubber, epoxy resins, etc., melamine resins, epoxy resins, polyimide resins, unsaturated polyester resins, etc. These resins can be used alone or in combination of two or more types. Among them, phenolic resin,
Modified phenolic resins are preferred.

Examples of the surfactant in the present invention include silicone surfactants such as alkoxysilane, and surfactants such as polyoxyalkylene adducts such as sorbitan and alkylphenol, and these may be used in combination. The amount used is 0.000 parts per 100 parts by weight of thermosetting root. 5-30! The range is preferably 1 part, but it is not necessarily unambiguous depending on the type.

The blowing agents used in the present invention include carbonates such as sodium carbonate, bicarbonates such as sodium bicarbonate, decomposition type blowing agents such as nitroso compounds, azo compounds, and sulfonyl hydrazide compounds, and hydrocarbons such as hexane and toluene. Volatile organic solvents, esters such as butyl acetate and amyl acetate.

These include volatile liquids such as Freon, and these can also be mixed together. The amount used is preferably in the range of 1 to 20 parts by weight per 100 parts by weight of the thermosetting resin, but this amount is not necessarily unique depending on the type of blowing agent.

In the present invention, a friction modifier is used, if necessary, for the purpose of stabilizing and improving frictional force. atIIn
Examples of the conditioner include inorganic powdery substances such as graphite, molybdenum disulfide, barium sulfate, and silica powder, and organic powdery substances such as cashew dust, fluororesin powder, and spherical phenol resin cured product powder. Furthermore, in order to improve the mechanical strength of the thermosetting resin that supports the foam structure, heat-resistant synthetic fibers such as glass fiber, carbon fiber, ceramic fiber, gold FX fiber such as steel and stainless steel, and aramid fiber are used. It is preferable to include it in the composition.

The wet friction material of the present invention is produced by uniformly mixing a composition consisting of a thermosetting resin, a surfactant, a foaming agent, and if necessary a friction modifier and fibers using a kneading device such as a kneader, and then heating the mixture. After foaming and curing in an atmosphere, it is processed into an appropriate shape, such as a ring shape, and then bonded to the core plate using a phenolic resin adhesive or the like.

The ratio of continuous pores in the total pores in the present invention (hereinafter referred to as
The continuous porosity) was determined by the following method.

The thermosetting resin was cured independently according to its curing conditions and then pulverized. The true volume of this powder was determined using an air hydrometer model 930 (Bayman Japan +!2) and the true specific gravity was measured. Similarly, the true specific gravity of the friction modifier and the fibers was determined, and the true specific gravity (ρm) of the cured composition was calculated from them. Next, the manufactured friction base material had a diameter of 20 rn.
rn+ A cylinder with a height of 20 mm is machined using force, and its weight (W
a) and measure the volume (Vm) with an air hydrometer,
It was calculated using the following formula.

A = 6.28-Vm B = 6.28-Wa/ρm Total porosity = B/6.28X100 Continuous porosity = A/BX ] 00 In addition, the pore diameter was determined from a scanning electron micrograph, The proportion of pores in the range of 5 to 200 μm was calculated from the distribution.

The wet friction material of the present invention has a total porosity of about 10 to 50% and a continuous porosity of about 20 to 70%. It can be easily manufactured by adjusting the density etc.

When the continuous porosity is 20% or less, the dynamic friction coefficient decreases, and when the continuous porosity is 70% or more, the N mechanical strength decreases and the amount of wear increases significantly. Further, the amount of the blowing agent is adjusted so that 75% or more of all the pores have a pore diameter in the range of 6 to 200 μm. When the proportion of pores with a diameter of 5 μm or less exceeds 25%, the dynamic g* coefficient decreases, and the pore diameter of 200%
If the porosity of μm or more accounts for 25% or more of the total porosity, the mechanical strength decreases and the amount of wear increases significantly.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

Examples Luzole type phenolic resin BRL-2760 (manufactured by Showa Kobunshi Co., Ltd., viscosity 3000 cps/25°C.

Non-volatile content: 80%) 100 parts by weight of sorbitan nonionic surfactant (Tween 40, manufactured by Seisei Atlas Co., Ltd.) 5
Parts by weight, 10 parts by weight of hexane, 75 parts by weight of diatomaceous earth, and 50 parts by weight of graphite were added and thoroughly kneaded using a kneader. Next, 5 parts by weight of short glass fibers (a fiber length: 5 mm) were added and quickly kneaded, and further, 60% para-toluenesulfonic acid aqueous M10Ji parts were added as a curing agent for the phenol resin, and mixed for 90 seconds. This composition has a radius of 150 m.
m.

Place it in a mold with a length of 150 nm and a height of 100 mm.70
C. for 2 hours to foam and harden to produce a block-shaped friction base material. The physical properties at this time were: density 0.6 g/cc+, total porosity 25%, and continuous porosity 40%.

The proportion of pores in the range of 5 to 200 μm among all pores is 90.
%Met.

Next, this block-shaped R rubbing base material was sliced into 0.5 mm thick pieces using a slicer, and further, using a lathe, the outer diameter was 133 mm.
It was processed into a ring shape with an inner diameter of 113 mm. Separately, apply phenolic resin adhesive BLS-2 to both sides of the ring-shaped core iron plate.
117A (Sho P [manufactured by 7 Kobunshi Co., Ltd.]) was applied and heated at 60℃2.
It was heated and dried for 0 minutes.

Both sides of the ring-shaped core iron plate coated with this adhesive have a thickness of O,
! A ring-shaped friction base material processed to 5 mm was laminated, and 20
Hot press adhesion was performed at 0° C. for 40 minutes at an actual pressure of 30 kg/cm 2 to obtain the desired wet friction material.

The friction characteristics were measured using an SAE #2 tester, and the conditions are shown in Table 1.

After the motor was rotated for 20 seconds at 3600 rprr+, the clutch was engaged to absorb inertia, and the motor was held for 10 seconds, making this cycle 1. This cycle is 200
After repeating the process several times, the dynamic R friction coefficient was measured and was 0.14.
It showed a high value of 4.

Furthermore, after continuing the test and repeating it 10,000 times, the dynamic lJ [coefficient was measured again, and it was 0.142, which showed almost no change, and stable characteristics were obtained.

In addition, the amount of wear after 10,000 cycles is as small as 20 μm, and μ
The O/μd ratio was a small and good value of 0.95.

Example 2 To 100 parts by weight of phenolic resin BRL-2760, 40 parts by weight of epoxy resin Epicoat 1oO1 (manufactured by Yuka Shell Co., Ltd.) and 20 parts by weight of cellosolve acetate were added, and the mixture was heated at 100°C.
After raising the temperature to 100°C, it was held at 100°C for 20 minutes. Thereafter, 100 parts by weight of the synthesized epoxy-modified phenol resin was cooled and an epoxy-modified phenol resin was synthesized, and a friction base material was produced in the same manner as in Example 1 using 5 parts by weight of Tween 40 or less.

The physical properties at this time were a density of 0.72 g/cc and a total porosity of 14%.
The continuous porosity was 26%, and the proportion of pores in the range of 5 to 200 μm among all pores was 79%. Furthermore, the desired wet IX scraped material was obtained in the same manner as in Example 1.

When this Il friction characteristic was measured, the dynamic friction coefficient after 200 cycles was 0.155, and the dynamic friction coefficient after I 0000 cycles was 0.150. g pure amount 8 μm.

The μ0/μd ratio showed a good value of 1.09.

Example 3 Epoxy resin Ebiko) 828 (Yuka Shell Co., Ltd. $%) 1
00 parts by weight with Tween 20 (Shosei Atlas Co., Ltd. $1)
0. 5 parts by weight and 7 parts by weight of toluene were added and heated to 105°C, followed by 75 parts of diatomaceous earth.

25 parts by weight of graphite, 511 parts by weight of barium sulfate.

Carbon fiber M-107T (manufactured by Kureha Chemical Co., Ltd.)
! i1! length 0.7mm)INI! , parts and 0.5 parts by weight of valatoluenesulfonyl hydrazide were added and thoroughly mixed. Next, after cooling to 95°C and adding 2 parts by weight of warm water and mixing, 6 parts by weight of diethylenetriamine was added as a hardening agent, and after quickly mixing, the mixture was poured into the mold used in Example 1 and foamed and hardened to form a friction base. was manufactured.

The physical properties are: density 0°48g/cc, total porosity 38%,
The continuous porosity was 31%, and the proportion of pores in the range of 5 to 200 μm among all pores was 87%.

Furthermore, the desired wet friction material was obtained in the same manner as in Example 1.

The friction characteristics at this time are that the dynamic friction coefficient is 0 after 200 cycles.
．． 139.Dynamic friction coefficient after 1000 cycles 0.138
．． The wear amount was 18 μm and the μ0/μd ratio was 1.11, both good values.

Example 4 Epoxidized polybutadiene E-1000-8 (manufactured by Five Seki Kagaku Co., Ltd.) in 100 parts by weight of phenolic resin BRL-2760
20! jl group was added, and a rubber-modified phenolic resin was synthesized in the same manner as in Example 2.Furthermore, a friction base material and a desired wet friction material were manufactured in the same manner as in Example 2. The characteristics are shown in Table 2.

Example 5 The same method as in Example 4 was followed except that the amount of epoxidized polybutadiene E-1000-8 added was 40 weight f1 kgB. The characteristics are shown in Table 2.

Example 6 The same method as in Example 2 was followed except that the amount of the epoxy resin (Ebiko) 1001 added was 20 parts by weight. The characteristics are shown in Table 2.

Example 7 Tung oil modified phenolic resin BLS-3122 (manufactured by Showa Kobunshi Co., Ltd., viscosity 4 Q Oc p S + non-volatile content 60%
), and the same method as in Example 1 was followed except that 5 parts by weight or less of Tween 40 was used. The characteristics are shown in Table 2.

Comparative Example 1 When the friction characteristics of a commercially available vapor wet friction material were measured according to the conditions shown in Table 1, the friction coefficient of movement after 200 cycles was 0.140, but it decreased to 0.114 after 10,000 cycles. The reduction rate of wrinkles was about 20%. Further, the μO/μd ratio was a good value of 1.10, but the amount of wear was 95 μm, which was approximately three times as much as the product of the present invention.

Comparative Example 2 When the friction characteristics of a commercially available elastomer wet friction material were measured, the dynamic friction coefficient after 200 cycles was 0.107.
and about 40% compared to the commercially available paper friction material of Comparative Example 1.
It was getting low. The coefficient of dynamic friction after 10,000 cycles is 0.106. Although the amount of wear was 4 μm, showing good durability, the originally required high coefficient of dynamic friction could not be obtained.

Comparative Example 3 The same method as in Example 1 was followed except that 15 parts by weight of hexane and 5 parts by weight of ethanol were used as blowing agents.

The continuous porosity of the obtained friction base material was 100%, and when its friction properties were measured, the dynamic R friction coefficient after 200 cycles was 0.135, but the amount of wear was 5 μm, which was already a large amount. Due to wear, it was impossible to continue the test.

Comparative Example 4 The same method as Example 1 was followed except that hexane was omitted from the composition of Example 1.

The ratio of the number of pores in the range of 5 to 200 μm in the total porosity of the obtained friction base material was 68%, and the size of the remaining pores was all 5 μm or less. When this KW characteristic was measured, the coefficient of dynamic friction after 200 cycles was extremely low at 0.085. Other properties are shown in Table 2.

Comparative Example 5 The same method as in Example 1 was followed except that 0.1 parts by weight of Tween 40 was used in the composition of Example I.

The continuous porosity of the obtained friction base material was 15%. When this friction property was measured, the dynamic H friction coefficient after 200 cycles was extremely low at 0.096. Other properties are shown in Table 2.

Table 1.5AE#2 Test Conditions [Effects of the Invention] The wet friction material according to the present invention has an excellent coefficient of dynamic friction,
Moreover, it has excellent durability and good μ even under high load conditions.
Since it has a 0/μd ratio, it is extremely useful for automobile clutches, wet brakes, etc.

Claims (1)

[Claims] 1. Continuous pores as a friction base material have a total porosity of 20 to 7.
A wet friction material characterized by using a thermosetting resin having a foam structure of 0%. 2. The wet friction material according to claim 1, wherein 75% or more of the total porosity has a pore diameter of 5 to 200 μm. 3. A wet friction material characterized by using a composite material obtained by filling the wet friction material of claim 1 or 2 with an inorganic/organic friction modifier and fibers.