JP2021127388A - Friction material composition for sliding member, friction material for sliding member and sliding member - Google Patents

Abstract

To provide a friction material for a sliding member having following properties: (1) The friction material excels in the stability of friction coefficient to repeated vibration; (2) The friction material is less likely to be cracked after repeated vibration; (3) The friction material faces an SUS board as a mating material; (4) The friction material has a high damping effect of vibration owing to a high average friction coefficient; and (5) The sliding noise during repeated vibration is small, and to provide a friction material composition for a sliding member which produces the friction material for a sliding member, and a sliding member using the friction material for a sliding member.SOLUTION: There is provided a friction material composition for a sliding member containing a binder, an organic filler, an inorganic filler, and a fiber base material. The friction material composition does not substantially contain a metal and contains 10 vol.% or more of cashew dust and 1 to 4 vol.% of an abrasive having a Mohs hardness of 5 or more in which at least a part of the cashew dust is cured by furfural.SELECTED DRAWING: None

Description

The present invention relates to a friction material composition for a sliding member, a friction material for a sliding member, and a sliding member.

In recent years, when a building or the like is repeatedly vibrated due to an earthquake or the like, there are many problems that damage to a building structure and a civil engineering structure (hereinafter, these are collectively referred to as a structure) occurs. For example, in a general building, the repeated vibration causes damage to main frames such as columns and beams, as well as seismic elements such as braces and walls.
As a method for reducing vibration and damage of a structure, for example, a method of adopting a seismic isolation device that reduces the seismic force itself entering the structure is used. However, it is known that in the case of a structure having an aspect ratio (height with respect to width) of 4 or more (for example, a high-rise building), the wind load tends to dominate, and the seismic isolation layer due to the wind load is known. It is necessary to suppress maximum deformation, residual deformation, and fatigue of the seismic isolation device. However, if the design of the seismic isolation device is changed so that the influence of the wind load is reduced in the structure with an aspect ratio of 4 or more, the seismic force entering the building will increase and the seismic isolation effect will be diminished. Since there is room for further improvement in seismic isolation devices, the development of new seismic isolation devices (for example, friction stoppers, etc.) has become an important theme.

In addition, as another damage, in a building with a steel-framed roof structure supported by a reinforced concrete frame, damages such as damage to steel members and steel-framed roof bearings near the surface wall frequently occur. As a means of reducing such damage, the bearings generally tend to be reinforced, but in that case, it is necessary to increase the yield strength enough to withstand the response of the reinforced concrete cantilever frame. Sufficient reinforcement of the part is not easy.

Therefore, in order to reduce or avoid the damage, it has been proposed to introduce energy absorbing members into braces of buildings and the like, seismic elements such as walls, and steel roof bearings. As one of the energy absorbing members, a sliding member, for example, a damper that attenuates vibration by friction can be mentioned. The friction damper is usually composed of a friction material and a stainless steel (SUS) plate as a mating material to which the friction material is rubbed, and absorbs vibration energy by damping due to friction between the friction material and the SUS plate. ..

Since the mating material of the friction material in the friction damper is a SUS plate, the required performance is different from that of the friction material used for disc brake pads whose mating material is generally cast iron. Therefore, even if the friction material used for the disc brake pad is diverted to the friction material of the friction damper, the required performance cannot be sufficiently satisfied.
For example, the characteristics required for a sliding member such as a friction damper are (1) stability of the coefficient of friction against repeated vibration due to an earthquake or the like, (2) no cracks in the friction material after repeated vibration, and (3) partner. It may come into contact with the SUS plate, which is a material, (4) the average friction coefficient of the friction material is high, the vibration damping effect is high, and (5) the sliding noise during repeated vibration is small.

As the friction material for the friction damper, SiC has a composition of 60 to 85% by weight, Fe ₂ O ₃ has a composition of 5 to 25% by weight, SiO ₂ has a composition of 5 to 20% by weight, and Al ₂ O ₃ has a composition of 2 to 10% by weight. A ceramic-based sliding part material (see Patent Document 1) is known. In addition, it is a lining for a friction damper that suppresses the vibration of the structural material constituting the building by the frictional force of the friction material, and is a friction material that reinforces the friction material and a friction that adjusts the frictional force of the friction material. A friction material including an adjusting material, a binder for binding the fiber material and the friction adjusting material, and a back plate to which the friction material is integrally fixed are provided, and the binder is thermocurable. The fibrous material contains a resin in a predetermined amount with respect to the friction material, and the friction adjusting material contains one or more kinds of solid lubricants with respect to the friction material in a predetermined amount, and has a moose hardness of 7. A predetermined amount of hard particles of 5 or less is contained in the friction material, the volume% ratio of the solid lubricant and the hard particles is in a predetermined range, and the friction material has a thickness ratio of the back plate in a predetermined range. A lining for a friction damper (see Patent Document 2) and the like are known.

However, when the friction material described in Patent Document 1 or Patent Document 2 is used for a brace of a building or the like, a seismic element such as a wall, or a friction damper of a steel roof support portion, it is difficult to come into contact with the mating material at the initial stage of installation, and the initial friction The coefficient is low, and the stability of the friction coefficient against "repeated vibration" cannot be obtained. Further, there is a drawback that the SUS plate of the mating material is easily worn by repeated friction due to "repeated vibration".

Further, in the comparative example of Patent Document 3, fiber base material 30% by volume, phenol resin 6% by volume, Al ₂ O ₃ 5% by volume, Fe ₂ O ₃ 8% by volume, cashew dust 5% by volume, graphite 5 Friction material containing% by volume, fiber base material 30% by volume, phenol resin 6% by volume, Al ₂ O ₃ 5% by volume, Fe ₂ O ₃ 8% by volume, cashew dust 9% by volume, graphite 9% by volume A friction material for a friction damper containing the above is described.

Japanese Unexamined Patent Publication No. 08-283070 Japanese Unexamined Patent Publication No. 2012-017759 Japanese Unexamined Patent Publication No. 2005-029648

The friction material for a friction damper described in the comparative example of Patent Document 3 contains cashew dust, but since cashew dust has a low decomposition point, the composition described in the comparative example of Patent Document 3 is used. The friction material has a problem that the stability of the friction coefficient decreases during "repeated vibration".

Therefore, the present invention has (1) excellent stability of the friction coefficient against repeated vibrations, (2) less likely to cause cracks in the friction material after repeated vibrations, and (3) face-to-face contact with the SUS plate which is the mating material. 4) Friction material for sliding members, which has the characteristics that the average friction coefficient of the friction material is high, the damping effect of vibration is high, and (5) the sliding noise during repeated vibration is small, the friction material for the sliding member. It is an object of the present invention to provide a friction material composition for a sliding member and a sliding member using the friction material for a sliding member.

As a result of diligent studies, the present inventors have substantially not contained metal, contained a predetermined amount of cashew dust and a grinding material having a Mohs hardness of 5 or more, and at least a part of the cashew dust was furfural. It has been found that the above-mentioned problems can be solved by using cashew dust hardened by.

That is, the present invention relates to the following [1] to [11].
[1] A friction material composition for a sliding member containing a binder, an organic filler, an inorganic filler, and a fiber base material.
It contains substantially no metal, and contains 1 to 4% by volume of an abrasive having a cashew dust of 10% by volume or more and a Mohs hardness of 5 or more.
A friction material composition for a sliding member, in which at least a part of the cashew dust is cured by furfural.
[2] The friction material composition for a sliding member according to the above [1], wherein the cashew dust is at least one selected from the group consisting of brown-black cashew dust and black cashew dust.
[3] The friction material composition for a sliding member according to the above [1] or [2], wherein the tar content extracted by the following method in the cashew dust is 5% by mass or less with respect to the total amount of cashew dust.
Method of extracting tar content: Cashew dust is heat-treated at 370 ° C. for 1 hour, and tar content is extracted with acetone from the residue after the heat treatment.
[4] The above-mentioned [1], wherein the abrasive is at least one selected from the group consisting of alumina, chromium dioxide, chromium trioxide, zirconium oxide, garnet, silicon dioxide, zirconium silicate, mullite, silicon carbide and Kongo sand. ] To [3]. The friction material composition for a sliding member.
[5] The friction material composition for a sliding member according to any one of the above [1] to [4], which further contains calcium carbonate.
[6] The friction material composition for a sliding member according to any one of the above [1] to [5], which further contains calcium hydroxide.
[7] The friction material composition for a sliding member according to any one of the above [1] to [6], which further contains diatomaceous earth.
[8] The friction material composition for a sliding member according to any one of the above [1] to [7], wherein the fiber base material contains at least one selected from the group consisting of organic fibers and inorganic fibers.
[9] The sliding member according to any one of [1] to [8] above, wherein the content of the fiber base material is 5 to 20% by volume with respect to the total amount of the friction material composition for the sliding member. Friction material composition.
[10] A friction material for a sliding member, which comprises the friction material composition for a sliding member according to any one of the above [1] to [9].
[11] A sliding member having a friction material for a sliding member and a back metal, which contains the friction material composition for a sliding member according to any one of the above [1] to [9].

According to the present invention, (1) the stability of the friction coefficient against repeated vibrations is excellent, (2) the friction material is less likely to crack after repeated vibrations, and (3) it comes into contact with the SUS plate which is the mating material. (4) Friction material for sliding members, which has the characteristics that the average friction coefficient of the friction material is high, the damping effect of vibration is high, and (5) the sliding noise during repeated vibration is small, and the friction for the sliding member. It is possible to provide a friction material composition for a sliding member that gives a material, and a sliding member that uses the friction material for a sliding member.
By using the sliding member friction material and the sliding member of the present invention, damage to the main frame such as columns and beams in a building such as a building is suppressed when repeated vibrations such as an earthquake occur, and further, reinforced concrete is used. In a building having a steel-framed roof structure supported by a frame, it is possible to prevent damage to the steel-framed members and the steel-framed roof support portion near the surface wall.
Further, the friction material for a sliding member of the present invention has excellent wind resistance, and effectively functions as a sliding member for a friction stopper of a wind resistant device that acts only on a wind load. The friction stopper does not require maintenance even after an earthquake occurs.

It is a schematic diagram for demonstrating the manufacturing method of the friction damper for evaluation in an Example and a comparative example. It is a schematic diagram for demonstrating the manufacturing method of the friction damper for evaluation in an Example and a comparative example. It is a schematic diagram for demonstrating the manufacturing method of the friction damper for evaluation in an Example and a comparative example. It is a schematic diagram for demonstrating the state of the evaluation friction damper produced in an Example and a comparative example.

Hereinafter, the present invention will be described in detail. However, in the following embodiments, the components are not essential unless otherwise specified. The same applies to the numerical values and their ranges, and does not limit the present invention.
In the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. Further, in the present specification, the content of each component in the friction material composition is the plurality of substances present in the friction material composition when a plurality of substances corresponding to the respective components are present, unless otherwise specified. Means the total content of the species substance.
The present invention also includes aspects in which the items described in the present specification are arbitrarily combined.

Hereinafter, the friction material composition for a sliding member, the friction material for a sliding member, and the sliding member of the present invention will be described in detail. The friction material composition for sliding members of the present invention is a friction material composition that does not contain asbestos, that is, a so-called non-asbestos friction material composition.

[Friction material composition for sliding members]
The friction material composition for a sliding member of the present invention is a friction material composition for a sliding member capable of attenuating repeated vibrations such as an earthquake, and specific examples of the sliding member include a damper (friction damper). Alternatively, vibration damping friction dampers), friction stoppers, and the like can be mentioned. That is, the friction material composition for a sliding member of the present invention can also be said to be a friction material composition for a damper and a friction material composition for a friction stopper.
Hereinafter, the friction material composition for a sliding member may be simply referred to as a friction material composition, and similarly, the friction material for a sliding member may be simply referred to as a friction material.

The present invention is a friction material composition containing a binder, an organic filler, an inorganic filler, and a fiber base material, which does not substantially contain a metal, has a cashew dust of 10% by volume or more and a Mohs hardness of 5 or more. This is a friction material composition for a sliding member, which contains 1 to 4% by volume of the abrasive material of the above, and at least a part of the cashew dust is hardened by furfural.
With the above configuration, (1) the stability of the friction coefficient against repeated vibration is excellent, (2) the friction material is less likely to crack after repeated vibration, and (3) it comes into contact with the SUS plate which is the mating material, and (4). ) The average friction coefficient of the friction material is high, the vibration damping effect is high, and (5) the sliding noise during repeated vibration is small. Here, "contacting the surface with the SUS plate" means a state in which the surface of the friction material and the surface of the SUS plate are in contact with each other with a small gap, and the surface of the friction material and the surface of the SUS plate are familiar. It can be said that it is in a state. On the contrary, the non-face-to-face state is a state in which the two are partially in contact with each other. The surface contact is the surface contact at the initial stage of repeated vibration.

As the metal substantially not contained in the friction material composition of the present invention, at least one selected from the group consisting of copper, aluminum, iron, zinc, tin, and copper, aluminum, iron, zinc and tin is contained. There is an alloy to be used.
In addition, in this specification, "substantially not contained" means that it is not contained at all (that is, it is 0% by mass) and is slightly contained to the extent that there is no effect by containing it (that is, it is contained in an amount of 0% by mass). For example, it also contains 1% by mass or less, 0.5% by mass or less, or 0.1% by mass or less).
Hereinafter, each component that can be contained in the friction material composition of the present invention will be described in detail.

(Binder)
The binder has a function of integrating the organic filler and the fiber base material contained in the friction material composition to give strength.
A thermosetting resin can be used as the binder. Examples of the thermocurable resin include unmodified phenolic resin; various elastomer-dispersed phenolic resins such as acrylic elastomer-dispersed phenolic resin and silicone elastomer-dispersed phenolic resin; acrylic-modified phenolic resin, silicone-modified phenolic resin, cashew-modified phenolic resin, and epoxy. Examples thereof include various modified phenolic resins such as modified phenolic resins and alkylbenzene modified phenolic resins. As the binder, one type may be used alone, or two or more types may be used in combination.
As the binder, unmodified phenol resin, acrylic modified phenol resin, silicone modified phenol resin, and alkylbenzene modified phenol resin are preferable, and unmodified phenol resin and silicone modified phenol resin are more preferable from the viewpoint of heat resistance, moldability and friction coefficient. preferable.

The content of the binder in the friction material composition is preferably 15 to 35% by volume, more preferably 20 to 30% by volume. By setting the content of the binder within the above range, cracks in the friction material tend to be prevented and the friction coefficient tends to be stabilized.

(Organic filler, cashew dust)
The organic filler is contained as a friction modifier for improving the wear resistance and the like of the friction material.
Examples of the organic filler include cashew dust, a rubber component, melamine dust and the like. In the present invention, it is essential that cashew dust is contained in an amount of 10% by volume or more based on the total amount of the friction material composition among these organic fillers. The cashew dust is obtained by crushing a polymerized and cured cashew nut shell oil. The average particle size of cashew dust is not particularly limited, but from the viewpoint of dispersion uniformity of the mixed material, 150 to 450 μm is preferable, 200 to 400 μm is more preferable, and 250 to 350 μm is further preferable. In the present specification, the average particle size means the value of d50 (median diameter of volume distribution, cumulative median value) measured by using the method of measuring the diffraction particle size distribution by laser, and the same applies hereinafter. For example, it can be measured with a laser diffraction / scattering type particle size distribution measuring device, trade name: LA.920 (manufactured by HORIBA, Ltd.).
By containing cashew dust in an amount of 10% by volume or more based on the total amount of the friction material composition, sufficient flexibility can be imparted to the friction material and the stability of the friction coefficient can be improved. The content of cashew dust is preferably 10 to 40% by volume, more preferably 10 to 35% by volume, further preferably 15 to 30% by volume, and particularly preferably 15 to 25% by volume, based on the total amount of the friction material composition. When the content of cashew dust is 40% by volume or less with respect to the total amount of the friction material composition, the decrease in heat resistance and the decrease in strength due to heat history tend to be suppressed.

Cashew dust is (i) brown cashew dust obtained by curing cashew nut shell oil with formaldehyde (or paraformaldehyde) or hexamine or cured without a cross-linking agent, and (ii) cashew nut shell oil obtained from full flare and formaldehyde (or). Brown-black cashew dust cured with paraformaldehyde) and (iii) cashew nut shell oil are classified into black cashew dust cured with full-fural.
The cashew dust used in the present invention is obtained by curing at least a part of cashew dust with furfural from the viewpoint of stability of friction coefficient and reduction of sliding noise during repeated vibration. That is, from the viewpoint of the stability of the friction coefficient and the reduction of sliding noise during repeated vibration, at least one selected from the group consisting of the brown-black cashew dust of (ii) and the black cashew dust of (iii). It is preferable to use. From the viewpoint of stability of friction coefficient and reduction of sliding noise during repeated vibration, it is preferable that at least a part of cashew dust cured by furfural is contained in an amount of 70% by mass or more, and 80% by mass or more. More preferably, it is further preferably contained in an amount of 90% by mass or more, and at least a part of the cashew dust cured by furfural may be substantially 100% by mass.

On the other hand, the brown cashew dust of (i) is soft and has a large coefficient of thermal expansion, but it reduces the stability of the friction coefficient and the reduction of sliding noise during repeated vibration. It is presumed that this is due to the generation of tar when the tea-based cashew dust of (i) is decomposed. The brown cashew dust of (ii) and the black cashew dust of (iii), in which at least a part of the cashew dust is hardened by furfural, are compared with the brown cashew dust of (i). It is hard and has a small thermal expansion, so it is considered that the fact that tar is less likely to be generated during decomposition affects the improvement of the stability of the friction coefficient and the reduction of sliding noise during repeated vibration. As the cashew dust, the black cashew dust of (iii) is more preferable from the viewpoint of the effect of improving the stability of the friction coefficient and the effect of reducing the sliding noise during repeated vibration.
From the viewpoint of the effect of improving the stability of the friction coefficient and the effect of reducing the sliding noise during repeated vibration, the tar content extracted by the following method in the cashew dust shall be 5% by mass or less with respect to the total amount of cashew dust. Is more preferable, 2% by mass or less is more preferable, 1.5% by mass or less is further preferable, and 1.2% by mass or less is particularly preferable. The lower limit of the tar content in cashew dust is not particularly limited, but may be 0.05% by mass or more, 0.2% by mass or more, or 0.5% by mass or more. There may be.
(Tar extraction method)
Cashew dust is heat-treated at 370 ° C. for 1 hour, and tar is extracted with acetone from the residue after the heat treatment.

Examples of the rubber component, which is an organic filler other than cashew dust, include natural rubber, acrylic rubber, isoprene rubber, polybutadiene rubber (BR), nitrile-butadiene rubber (NBR), and styrene-butadiene rubber (SBR). Examples thereof include PTFE (polytetrafluoroethylene). As the rubber component, one type may be used alone, or two or more types may be used in combination. Since the rubber component does not generate a tar component during decomposition, it is considered that it does not affect the stability of the friction coefficient.
When the friction material composition of the present invention contains a rubber component, the content thereof is preferably 1 to 10% by volume, more preferably 2 to 10% by volume, based on the total amount of the friction material composition. It is more preferably 3 to 7% by volume.
When cashew particles and a rubber component are used in combination, cashew particles coated with a rubber component may be used, or they may be used separately. From the viewpoint of giving sufficient flexibility to the friction material, it is preferable to use cashew dust and a rubber component in combination.

The total content of the organic filler in the friction material composition of the present invention is not particularly limited, but is preferably 11 to 50% by volume, preferably 15 to 40% by volume, based on the total amount of the friction material composition. It is more preferably 50% by volume, further preferably 15 to 35% by volume, and particularly preferably 20 to 30% by volume. By setting the total content of the organic filler in the above range, the friction coefficient tends to be stable at the initial stage of vibration because it comes into contact with the SUS plate which is the mating material, and the heat resistance at high temperature deteriorates. And there is a tendency to avoid a decrease in the stability of the friction coefficient due to the thermal history at high temperature.

(Inorganic filler, abrasive with Mohs hardness of 5 or more)
The friction material composition of the present invention may contain an inorganic filler. The inorganic filler can be broadly classified into a abrasive having a Mohs hardness of 5 or more, which increases the friction coefficient of the friction material, and an inorganic filler other than the abrasive.
The abrasive used in the present invention can be said to be an inorganic filler having a Mohs hardness of 5 or more. The Mohs hardness of the abrasive may be 5.5 or more, or 6 or more. The upper limit of the Mohs hardness of the abrasive is not particularly limited, but from the viewpoint of suppressing sliding noise during repeated vibration, the Mohs hardness is preferably 10 or less, more preferably 9 or less, further preferably 8 or less, and 7 or less. Is particularly preferable.
The friction material composition of the present invention contains 1 to 4% by volume of a grinding material having a Mohs hardness of 5 or more with respect to the total amount of the friction material composition. When the content of the abrasive is 1% by volume or more, a sufficiently high friction coefficient is exhibited, and when it is 4% by volume or less, the SUS plate, which is the mating material, is not excessively worn. From the viewpoint of developing a sufficiently high coefficient of friction, the content of the abrasive is preferably 1.5 to 4% by volume, more preferably 2 to 4% by volume, based on the total amount of the friction material composition. preferable. On the other hand, from the viewpoint of not excessively wearing the SUS plate which is the mating material, the content of the abrasive is preferably 1 to 3% by volume, preferably 1 to 2% by volume, based on the total amount of the friction material composition. More preferably.
The abrasive is not particularly limited as long as it is an inorganic filler having a Mohs hardness of 5 or more, but for example, alumina, chromium dioxide, chromium trioxide, zirconium oxide, garnet, silicon dioxide, zirconium silicate, mullite, silicon carbide, and Kongo sand. And so on. As the abrasive, one type may be used alone, or two or more types may be used in combination. Among these, alumina is preferable as the grinding material. Examples of the alumina include α-alumina and γ-alumina, which may be used, but γ-alumina (Mohs hardness 5 to 6) is preferable.
The average particle size of the abrasive is not particularly limited, but is preferably 1 to 10 μm, more preferably 3 to 10 μm, from the viewpoint of improving the friction coefficient.

Examples of the inorganic filler other than the grinding material include solid lubricants such as graphite, antimony trisulfide, tin sulfide, molybdenum disulfide, iron sulfide, bismuth sulfide, and zinc sulfide; calcium hydroxide, calcium oxide, sodium carbonate, etc. Calcium carbonate, magnesium carbonate, barium sulfate, diatomaceous soil, dolomite, coke, mica, iron oxide, vermiculite, radiolite, calcium sulfate, potassium titanate (potassium octatate, potassium hexatitate, etc.), lithium potassium titanate, titanium Examples thereof include potassium magnesium acid, sodium titanate, talc, clay, zeolite, chromate, magnesium oxide, iron oxide and the like. As the inorganic filler other than the abrasive, one type may be used alone, or two or more types may be used in combination.

By containing the solid lubricant, the wear resistance of the friction material can be improved. As the solid lubricant, graphite is preferable from the viewpoint of wear resistance of the friction material. The graphite is not particularly limited, and any known graphite, that is, natural graphite or artificial graphite can be used. Examples of natural graphite include earthy graphite, scaly graphite and scaly graphite. Further, the artificial graphite is usually produced by graphitization treatment using petroleum coke or coal-based pitch coke as a main raw material, and examples thereof include Kish graphite, decomposed graphite and thermally decomposed graphite. The average particle size of graphite is not particularly limited, but is preferably 0.1 to 100 μm, more preferably 1 to 80 μm, and even more preferably 1 to 50 μm from the viewpoint of wear resistance.
When the friction material composition of the present invention contains a solid lubricant, the content thereof is not particularly limited, but is preferably 0.1 to 5% by volume with respect to the total amount of the friction material composition. , 0.5 to 3% by volume, more preferably. Further, it is also preferable that the friction material composition of the present invention does not contain a solid lubricant.

Among the above, calcium carbonate, calcium hydroxide, and diatomaceous earth are preferable as the inorganic filler other than the abrasive and the solid lubricant. As the diatomaceous earth, calcined diatomaceous earth is preferable from the viewpoint of reducing impurities and reducing hygroscopicity.
By including calcium carbonate in the friction material composition of the present invention, the strength of the friction material can be increased. The calcium carbonate may be surface-treated or unsurface-treated. When the friction material composition of the present invention contains calcium carbonate, the content thereof is preferably 5 to 35% by volume, more preferably 10 to 25% by volume, and 15 to 25% by volume with respect to the total amount of the friction material composition. Is even more preferable.
By containing calcium hydroxide in the friction material composition of the present invention, the pH of the friction material is increased, and the effect of suppressing the generation of rust on the friction material can be obtained. When the friction material composition of the present invention contains calcium hydroxide, the content thereof is preferably 0.5 to 12% by volume, more preferably 3 to 10% by volume, and 3 to 3 to 10% by volume, based on the total amount of the friction material composition. 7% by volume is more preferable.
By containing diatomaceous earth in the friction material composition of the present invention, the friction material can contain pores and the friction coefficient can be stabilized. When the friction material composition of the present invention contains diatomaceous earth, the content thereof is preferably 5 to 30% by volume, more preferably 10 to 25% by volume, and 12 to 20% by volume, based on the total amount of the friction material composition. More preferred.

The total content of the inorganic filler is preferably 20 to 70% by volume, more preferably 30 to 65% by volume, and 30 to 55% by volume, based on the total amount of the composition for the friction material. Is even more preferable. By setting the total content of the inorganic filler in the above range, deterioration of heat resistance tends to be avoided.

(Fiber base material)
The fiber base material exhibits a reinforcing action in the friction material. The fiber base material preferably contains at least one selected from the group consisting of organic fibers and inorganic fibers. It should be noted that the metal fiber is not included in the fiber base material referred to in the present invention because it causes rust during long-term installation and there is a concern that it may adhere to SUS.
The combined use of organic fibers and inorganic fibers is preferable because the stability of the friction coefficient tends to be high.

Examples of the organic fiber include aramid fiber, acrylic fiber, cellulose fiber, phenol resin fiber and the like. One type of organic fiber may be used alone, or two or more types may be used in combination. Among these, it is preferable to use aramid fiber from the viewpoint of heat resistance and reinforcing effect.
The organic fiber preferably contains fibrillated organic fiber, and more preferably contains fibrillated aramid fiber. Fibrilized organic fibers are organic fibers that are defibrated and have fluff, and are commercially available.

When the friction material composition of the present invention contains organic fibers, the content thereof is not particularly limited, but is preferably 1 to 15% by mass, more preferably 1 with respect to the total amount of the friction material composition. It is 10% by mass, more preferably 1.5 to 6% by mass, and particularly preferably 1.5 to 4% by mass. If it is above the lower limit, good shear strength, crack resistance and wear resistance tend to be exhibited, and if it is below the upper limit, shear due to uneven distribution of organic fibers and other materials in the friction material composition. There is a tendency that deterioration of strength and crack resistance can be effectively suppressed.

Examples of the inorganic fiber include glass fiber, wollastonite, rock wool, ceramic fiber, biodegradable ceramic fiber, mineral fiber, carbon fiber, aluminosilicate fiber and the like. Among these, glass fiber is preferable from the viewpoint of reinforcing effect.
Glass fiber refers to a fiber produced by melting and spinning glass. As the glass fiber, those whose raw materials are E glass, C glass, S glass, D glass and the like can be used, and among these, glass containing E glass or S glass from the viewpoint of particularly high strength. It is preferable to use fiber. Further, in order to improve the affinity with the binder, the glass fiber whose surface is treated with aminosilane, epoxysilane or the like may be used.

The average fiber length of the glass fiber is not particularly limited, but is preferably 80 to 6,000 μm, more preferably 150 to 5,000 μm, and even more preferably 300 to 4,000 μm. When the average fiber length is 80 μm or more, the strength of the friction material tends to be improved, and when it is 6,000 μm or less, the decrease in dispersibility of the glass fiber tends to be suppressed. The average fiber diameter of the glass fibers is preferably 5 to 20 μm, more preferably 7 to 15 μm. When the average fiber diameter is 5 μm or more, it is possible to suppress the glass fiber from breaking when each component of the friction material composition is mixed, and when it is 20 μm or less, the strength of the friction material tends to be improved. In the present specification, for the average fiber length and the average fiber diameter, 50 inorganic fibers to be used are randomly selected, the fiber length and the fiber diameter are measured with an optical microscope, and the average values obtained from the measurements are shown. If, you can refer to the catalog value. In the present specification, the fiber diameter refers to the diameter of the fiber.
The content of the inorganic fibers (particularly glass fibers) in the friction material composition of the present invention is not particularly limited, but is preferably 1 to 10% by volume with respect to the total amount of the friction material composition. More preferably, it is 3 to 8% by volume. By setting the content of the glass fiber in the above range, toughness can be imparted without impairing the handleability of the friction material composition after mixing, and the strength of the friction material can be improved.

The content of the fiber base material in the friction material composition is preferably 5 to 20% by volume, more preferably 5 to 15% by volume, further preferably 5 to 12% by volume, and particularly preferably 5 to 10% by volume. By setting the content of the fiber base material in the above range, appropriate material strength is obtained, good wear resistance is exhibited, and moldability tends to be good.

(Other ingredients)
In addition, the friction material composition of the present invention may contain other components other than the above-mentioned components, if necessary, to the extent that the effects of the present invention are not impaired.
Examples of other components include curing agents such as hexamethylenetetramine, hexamethoxymethylolmelamine, and resol resins; and curing accelerators such as p-toluenesulfonic acid.
When the friction material composition of the present invention contains the above other components, the content thereof is preferably 5% by mass or less, more preferably 3% by mass or less, respectively, with respect to the total amount of the friction material composition. , Other components may not be contained.

[Friction material for sliding member and sliding member]
The present invention also provides a friction material for a sliding member, which comprises the friction material composition for a sliding member. The present invention further provides a sliding member having a friction material for a sliding member and a back metal, which contains the friction material composition for the sliding member.
The friction material for sliding members of the present invention has (1) excellent stability of friction coefficient against repeated vibration, (2) less likely to crack the friction material after repeated vibration, and (3) with respect to the SUS plate which is the mating material. It has the characteristics that (4) the average friction coefficient of the friction material is high, the vibration damping effect is high, and (5) the sliding noise during repeated vibration is small. Therefore, in braces of buildings and sliding members (or energy absorbing members) in earthquake-resistant elements such as walls, and in buildings with steel-framed roof structures supported by reinforced concrete frames, sliding members in steel-framed members near the surface wall (or sliding members). Alternatively, it is useful as an energy absorbing member) and a sliding member (or energy absorbing member) in a steel frame roof support portion.

Further, the friction material for a sliding member of the present invention is also useful as a sliding member for a friction stopper of a windproof device that acts only on a wind load. The friction stopper has a structure consisting of a friction material and a SUS plate, and resists the wind by not sliding due to static friction force under wind load, and slides during an earthquake to release the friction stopper and seismic isolation. The device exerts its original seismic isolation effect. The friction stopper does not require maintenance even after an earthquake occurs.

Examples of the sliding member of the present invention include, but are not limited to, the following configurations.
(1) Consists of only friction material for sliding members.
(2) A configuration having a back metal and a friction material for a sliding member of the present invention formed on the back metal.
(3) In the configuration of (2) above, the primer layer (a) and the back metal and the friction material for the purpose of surface modification for enhancing the adhesive effect of the back metal between the back metal and the friction material for the sliding member. A configuration in which at least one selected from the group consisting of an adhesive layer (b) for the purpose of adhering is further interposed.
Among these, the configuration of the above (2) or (3) (that is, the sliding member having the friction material for the sliding member of the present invention and the back metal) is preferable, and the configuration of the above (3) is more preferable.

The back metal can improve the mechanical strength of the sliding member. Examples of the material of the back metal include metal and fiber reinforced plastic. More specifically, for example, iron, stainless steel, inorganic fiber reinforced plastic, carbon fiber reinforced plastic and the like can be mentioned. As the primer layer and the adhesive layer, for example, a primer layer or an adhesive layer used for a friction member such as a brake lining or a brake pad can be used as it is.

The friction material for a sliding member of the present invention can be manufactured by using, for example, a method generally used when manufacturing a brake lining, a brake pad, or the like. Specifically, the friction material for a sliding member of the present invention can be produced by heat-pressing molding the friction material composition for a sliding member of the present invention. Specifically, for example, the friction material composition for a sliding member of the present invention is used as a Reedige mixer (“Redige” is a registered trademark), a pressure kneader, and an Erich mixer (“Eirich” is a registered trademark). Mix well using a mixer such as, etc., premold the obtained mixture with a molding mold, and premold the obtained premolded product at a molding temperature of 130 to 160 ° C., a molding pressure of 20 to 50 MPa, and a molding time of 2 to 10 The friction material for a sliding member of the present invention can be obtained by molding under the condition of 1 minute and heat-treating the obtained molded product at 150 to 250 ° C. for 1 to 5 hours. The friction material for the sliding member may be one that has been subjected to a polishing treatment or the like.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is not limited thereto.

<Examples 1 and 2, Comparative Examples 1 and 5>
[Manufacturing of friction material for sliding members]
Each component was blended according to the blending amount shown in Table 1 to obtain a friction material composition for a sliding member (friction material composition for a damper or a friction material composition for a friction stopper) of each example.
The friction material composition for sliding members obtained in each example is mixed with "Radige (registered trademark) mixer M20" (trade name, manufactured by Matsubo Co., Ltd.), and the obtained mixture is molded and pressed (manufactured by Oji Machinery Co., Ltd.). ), And the obtained preformed product was heat-press molded together with an iron backing using a molding press under the conditions of a molding temperature of 145 ° C., a molding pressure of 30 MPa, and a molding time of 5 minutes. The product was heat-treated at 200 ° C. for 4.5 hours and polished using a rotary polishing machine to obtain a friction material for a sliding member (friction material thickness 5 mm, friction material projected area 44 cm ² ).

The various materials used in each example are as follows. The amount of tar extracted from cashew dust was measured according to the following method.
<Tar extraction method>
Cashew dust was heat-treated at 370 ° C. for 1 hour, and tar was extracted with acetone from the residue after the heat treatment.

(Binder)
-Phenol resin (unmodified): Made by Hitachi Kasei Co., Ltd. (organic filler)
-Black cashew dust: trade name "6251-1" (manufactured by Cashew Co., Ltd.), average particle size 300 μm, tar content extracted by the above method: 1% by mass
-Brown cashew dust: trade name "B200" (manufactured by Cashew Co., Ltd.), average particle size 300 μm, tar content extracted by the above method: 7% by mass
・ NBR powder (rubber component)
(Inorganic filler)
-Γ-Alumina (abrasive): Mohs hardness 5-6, manufactured by Albemarle Corporation-Calcium carbonate-Calcium hydroxide-Baked diatomaceous earth (fiber base material)
・ Aramid fiber (organic fiber)
・ Glass fiber (inorganic fiber)

Various performance evaluations were performed on the friction materials for sliding members of each example produced by the above method according to the following methods. The results are shown in Table 1.

[Performance evaluation method]
(1. Stability of coefficient of friction against repeated vibration)
First, the friction coefficient was measured for the friction material for the sliding member of each example. The friction coefficient was calculated by the following method after preparing the evaluation friction damper by the following method.
<Manufacturing of friction damper for evaluation>
(I. Preparation of friction damper for evaluation)
A method for manufacturing the evaluation friction damper will be described with reference to FIGS. 1 to 4.
First, as shown in FIG. 1, a phenol resin adhesive "110" (manufactured by Cemedine Co., Ltd., trade name) was placed on one side of a 6 mm thick SUS plate (manufactured by SUS304, for outer plates) having bolt holes in two places. ) Was used to prepare four outer plates 5 to which four friction materials 1 for sliding members were adhered and fixed.
Next, as shown in FIG. 2, four SUS plates 2 (manufactured by SUS304) are adhered to both sides of a 12 mm thick plate having elongated holes at two locations, and the temperature sensor 3 is attached. One of the provided middle plates 4 was prepared.
Then, one middle plate 4 is sandwiched by the two outer plates 5 with the friction material 1 for the sliding member inside, and then a bolt via the disc spring 7 and the load cell 6 is inserted into the central hole. A friction damper for evaluation (see the combined view of FIG. 4), which is a sliding member, was produced by sandwiching the middle plate 4 between four friction members 1 for sliding members per side and applying pressure. .. The left (a) in FIG. 3 shows the state of the evaluation friction damper when viewed from the left side (see the eye (a) in FIG. 4), and the right (b) in FIG. 3 shows the evaluation friction damper. Is viewed from the right side (see eye (b) in FIG. 4).
(Ii. Method of measuring friction coefficient)
The middle plate 4 of the evaluation friction damper was connected to the upper load cell of the autograph "AGX-100kN" (manufactured by Shimadzu Corporation), and the outer plate 5 was connected to the lower gripper. By tightening the pressure bolt 8, the pressure axial force per pressure bolt was set to 75 kN.
Under the conditions of total sliding area (44 x 2) cm ² , sliding speed 20 mm / sec, and sliding distance ± 30 mm, the evaluation friction damper is slid back and forth for 5 cycles, and the frictional force (friction force) is applied to the upper load cell 6. kN) was measured. From the frictional force, the friction coefficient μ (μ before the repeated proof stress test) was obtained based on the following formula.
μ = P / (ΣN × m)
[Μ: friction coefficient, P: friction force (kN), ΣN: total axial force of bolts (kN), m: number of friction surfaces (2 because friction is performed on both sides of the middle plate)]
Next, the evaluation friction damper was subjected to a 150-cycle repeated strength test under the same conditions as described above, and then the friction coefficient μ (μ after the repeated strength test) after 150 cycles was determined by the same method. ..
The friction coefficient after the repeated proof stress test was evaluated according to the following evaluation criteria with respect to the friction coefficient before the repeated proof stress test. The stability of the coefficient of friction with respect to repeated vibration is in the order of A>B>C> D.
A: The rate of decrease in the coefficient of friction is 5% or less.
B: The rate of decrease in the coefficient of friction is more than 5% and 15% or less.
C: The rate of decrease in the coefficient of friction is more than 15% and 30% or less.
D: The rate of decrease in the coefficient of friction is more than 30%.

(2. Presence or absence of cracks after repeated vibration)
The appearance of the friction material for the sliding member after the 150-cycle repeated proof stress test was visually observed and evaluated according to the following evaluation criteria.
A: No cracks were confirmed.
C: Occurrence of cracks was confirmed.

(3. Face-to-face contact with the mating material (SUS plate))
The surface hardness of the friction material for the sliding member was measured using the Rockwell hardness S scale (HRS), and this was used as an index of the surface contact with the mating material (SUS plate) and evaluated according to the following evaluation criteria. The goodness of surface contact with the mating material (SUS plate) is in the order of A> C.
A: Hardness (HRS) is 115 or less.
C: Hardness (HRS) is over 115.

(4. Average coefficient of friction)
The repeated strength test of 150 cycles in the item of "1. Stability of friction coefficient with respect to repeated vibration" was carried out, the friction coefficient for each cycle was obtained by the same method as described above, and the average friction coefficient for 150 cycles was obtained. ..
The average coefficient of friction is preferably 0.25 or more.

(5. Sliding noise during repeated vibration)
A 150-cycle repeated proof stress test was carried out in the item of "1. Stability of friction coefficient against repeated vibration", and the sliding noise of the friction material for the sliding member after the test was observed and evaluated according to the following evaluation criteria.
A: No sliding noise is generated.
B: Only high frequency sound was generated. However, the incidence was 20% or less.
C: Both high-frequency sound and low-frequency sound were generated. However, the incidence was 20% or less.
D: The generation of sliding noise exceeded 20%.

The friction materials for sliding members of Examples 1 and 2 are (1) excellent in the stability of the friction coefficient against repeated vibrations, (2) the friction material is less likely to crack after repeated vibrations, and (3) SUS as a mating material. It can be seen that it has the characteristics of (4) having a high average friction coefficient of the friction material, having a high vibration damping effect, and (5) having a small sliding noise during repeated vibration. ..
On the other hand, in Comparative Examples 1 and 2 in which the content of cashew dust is 0% by volume or less than 10% by volume, (1) the stability of the friction coefficient with respect to repeated vibration deteriorates, and (3) the SUS plate as the mating material On the other hand, it was difficult to hit the surface, and (5) the sliding noise during repeated vibration was loud. In Comparative Example 3 in which brown cashew dust having no portion cured by full flare was used as cashew dust, (1) the stability of the friction coefficient against repeated vibration deteriorated, and (4) the average friction coefficient of the friction material decreased. However, (5) the sliding noise during repeated vibration was loud. In Comparative Examples 4 and 5 in which the content of the abrasive was less than 1% by volume, (1) the stability of the friction coefficient with respect to repeated vibration was slightly lowered, and (4) the average friction coefficient of the friction material was lowered.

The friction material and the friction member containing the friction material composition for the sliding member of the present invention are supported by the sliding member (or energy absorbing member) in the brace of a building or the like and the seismic element such as a wall, and the reinforced concrete frame. In a building with a steel frame roof structure, it is useful as a sliding member (or energy absorbing member) in a steel frame member near the surface wall, a sliding member (or energy absorbing member) in a steel roof support portion, and the like.
Further, the friction material for a sliding member of the present invention is also useful as a sliding member for a friction stopper of a wind resistant device that acts only on a wind load.

1 Friction material for sliding members 2 SUS plate 3 Temperature sensor 4 Middle plate 5 Outer plate 6 Load cell 7 Belleville spring 8 Pressurizing bolt

Claims (11)

A friction material composition for a sliding member containing a binder, an organic filler, an inorganic filler, and a fiber base material.
It contains substantially no metal, and contains 1 to 4% by volume of an abrasive having a cashew dust of 10% by volume or more and a Mohs hardness of 5 or more.
A friction material composition for a sliding member, in which at least a part of the cashew dust is cured by furfural. The friction material composition for a sliding member according to claim 1, wherein the cashew dust is at least one selected from the group consisting of brown cashew dust and black cashew dust. The friction material composition for a sliding member according to claim 1 or 2, wherein in the cashew dust, the tar content extracted by the following method is 5% by mass or less with respect to the total amount of cashew dust.
Method of extracting tar content: Cashew dust is heat-treated at 370 ° C. for 1 hour, and tar content is extracted with acetone from the residue after the heat treatment. 3. The friction material composition for a sliding member according to any one of the items. The friction material composition for a sliding member according to any one of claims 1 to 4, further containing calcium carbonate. The friction material composition for a sliding member according to any one of claims 1 to 5, further containing calcium hydroxide. The friction material composition for a sliding member according to any one of claims 1 to 6, further containing diatomaceous earth. The friction material composition for a sliding member according to any one of claims 1 to 7, wherein the fiber base material contains at least one selected from the group consisting of organic fibers and inorganic fibers. The friction material composition for a sliding member according to any one of claims 1 to 8, wherein the content of the fiber base material is 5 to 20% by volume with respect to the total amount of the friction material composition for a sliding member. .. A friction material for a sliding member, which comprises the friction material composition for a sliding member according to any one of claims 1 to 9. A sliding member having a friction material for a sliding member and a back metal, which contains the friction material composition for a sliding member according to any one of claims 1 to 9.

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