JP2018119236A - Organic fiber cord for friction material reinforcement and clutch facing comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic fiber cord for friction material reinforcement, specifically one having significantly improved adhesion to a base material containing a friction modifier and a thermosetting resin, and achieving improvements in wear resistance and frictional coefficient stability, and a clutch facing comprising the same.SOLUTION: An organic fiber cord for friction material reinforcement has a resin coating containing an epoxy compound on a cord.SELECTED DRAWING: None

Description

  The present invention relates to an organic fiber cord for reinforcing a friction material, and more particularly, a cord used for a facing material used for a clutch disk of a dry clutch, which has greatly improved adhesion and wear resistance to a clutch facing matrix. The present invention relates to an organic fiber cord for reinforcing friction materials.

  In clutches used in vehicles such as automobiles, the use of the clutch facing, which is a friction material, becomes extremely hot when used in a high-load region where a half-clutch is frequently used. There are many cases. In particular, in recent years, as a need for clutch facing, improvement in wear resistance due to higher output of an engine and stability of a friction coefficient in a high temperature region are required.

  In the invention described in Patent Document 1, the wear resistance is improved by using a base material including a friction modifier in which an aromatic polyamide fiber, a rock fiber, and a glass fiber are twisted together. It is well known that organic fibers such as aromatic polyamide fibers contribute to the improvement of wear resistance. This is thought to be because the organic fibers having excellent wear resistance are exposed on the surface of the clutch facing, thereby suppressing the wear of the surrounding matrix.

  However, synthetic fibers such as aromatic polyamide fibers often have a relatively inert surface, and as such, the adhesiveness to the thermosetting resin that is the matrix of the clutch facing becomes insufficient, resulting in a clutch. When the facing is worn, the integration of the organic fiber cord and the matrix becomes insufficient, and there remains a problem that the contribution to the improvement of the wear resistance and the stability of the friction coefficient cannot be sufficiently exhibited.

Japanese Patent Laid-Open No. 62-292937

  The present invention relates to an organic fiber cord for reinforcing a friction material. More specifically, the adhesion between a friction modifier and a base material containing a thermosetting resin is greatly improved, and the wear resistance and friction coefficient stability can be improved. Another object of the present invention is to provide an organic fiber cord for reinforcing a friction material and a clutch facing using the same.

  An organic fiber cord for reinforcing a friction material, comprising a resin film containing an epoxy compound on the surface of the yarn, and a base material containing the organic fiber cord for reinforcing the friction material and a friction modifier, and a thermosetting resin A clutch facing is provided which is impregnated.

  According to the present invention, the adhesion between the friction modifier and the base material containing the thermosetting resin, the wear resistance, and the coefficient of friction stability are greatly improved, and it is suitably used as a clutch facing that is excellent in overall durability. Organic fiber cords can be produced. By improving durability, energy saving effect can be expected by improving the life of the clutch facing.

  In the organic fiber cord for reinforcing a friction material of the present invention, a resin film containing an epoxy compound is present on the surface of the yarn. Organic fibers include aromatic polyamide fiber, vinylon fiber, polypropylene fiber, polyethylene fiber, polyarylate fiber, polybenzoxazole (PBO) fiber, nylon fiber, polyester fiber, acrylic fiber, vinyl chloride fiber, polyketone fiber, cellulose fiber, Organic fibers such as pulp fibers can be mentioned, and these can be used alone or in combination of two or more.

  In particular, from the viewpoint of wear resistance, it is preferably an organic fiber starting from a resin composed of an organic high molecular polymer, and in particular, an aromatic polyamide fiber that is an organic fiber excellent in strength, heat resistance, and wear resistance. Is preferred. Among these, para-aramid fibers such as polyparaphenylene terephthalamide, which is an aromatic polyamide fiber, are preferable from the comprehensive viewpoints such as strength, heat resistance, and wear resistance. Furthermore, among these aramid fibers, copolymer-type aramid fibers are particularly excellent in wear resistance and are preferably used. Specifically, copolyparaphenylene · 3,4'oxydiphenylene · terephthalamide fiber, which is a copolymerized para-type aramid fiber, is particularly preferred because it has superior wear resistance compared to other fibers.

  In addition, organic fibers such as aromatic polyamide fibers with excellent wear resistance, and inorganic fibers such as carbon fibers, glass fibers, basalt fibers (basalt fibers), ceramic fibers, asbestos fibers, etc. with excellent heat resistance It is also preferable to twist and use the fibers. In particular, it is preferable to combine with glass fiber from the viewpoint of cost. Further, it is also preferable to use a metal wire in combination in order to improve the heat conduction wire. When these two or more kinds of fibers are used in combination, the resin treatment described in the present invention may be twisted with other fibers after being treated with aromatic polyamide fibers alone, or twisted with other fibers. It may be processed later.

  The single yarn fineness of the organic fiber is preferably 0.6 to 80 dtex, more preferably 0.6 to 50 dtex, and even more preferably 1.5 to 6.0. The total fineness of the organic fiber in the organic fiber cord is preferably 1500 dtex to 8000 dtex, more preferably 3000 dtex to 8000 dtex. When combining with inorganic fibers, the ratio of organic fibers to inorganic fibers is preferably a volume ratio of 80:20 to 20:80. Increasing the proportion of inorganic fibers often leads to cost advantages, but wear resistance decreases.

  In the present invention, an epoxy compound having a high chemical affinity with the fiber surface and other organic compounds is treated on the surface of the organic fiber such as an aromatic polyamide fiber having poor surface activity. Specific examples of the epoxy compound to be treated on the surface of the fiber include a reaction product of a polyhydric alcohol such as ethylene glycol, glycerol, sorbitol, pentaerythritol, and polyethylene glycol and a halogen-containing epoxide such as epichlorohydrin, resorcinol. Reaction products of polysphenols such as bis (4-hydroxyphenyl) dimethylmethane, phenol / formaldehyde resin, resorcin / formaldehyde resin and the halogen-containing epoxides, unsaturated compounds with peracetic acid or hydrogen peroxide, etc. Polyepoxide compounds obtained by oxidation, namely 3,4-epoxycyclohexene epoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexenecarboxylate, bis (3,4-epoxy-6-methyl) - and a cyclohexyl methyl) Ajibeto. Among these, a reaction product of a polyhydric alcohol and epichlorohydrin, that is, a compound produced by a polyepoxide compound such as a polyglycidyl ether compound of a polyhydric alcohol and a curing agent is preferable because it exhibits excellent performance.

  The polyepoxide compound is usually used as an emulsified liquid using a known emulsifier, for example, sodium alkylbenzene sulfonate, dioctylsulfosuccinate sodium salt and the like. Polyepoxide compounds include amine-based, imidazole-based curing agents or polyisocyanates and blocked polyisocyanates, which are addition compounds of known oximes, phenols, caprolactams and other blocking agents, and ethylene urea, which is a reaction compound with ethyleneimine described below. Can be used mixed. The mixing ratio of the polyepoxide compound (A) and the curing agent, blocked polyisocyanate or ethylene urea (B) is 0.05 ≦ (A) / [(A) + (B)] ≦ 0.9 (weight ratio). A range is preferred.

  As a method for treating the fiber surface with the epoxide compound, an emulsion containing a polyepoxide compound (A) and a curing agent, blocked polyisocyanate or ethylene urea (B) is mixed with an oil agent in a fiber spinning process to form fibers. It is made to adhere, or it is made to adhere in a process different from a yarn production process after fiber yarn production. After adhesion of the emulsifier, heat treatment is performed at 100 to 250 ° C. for 10 to 120 seconds. If the solid content adhesion amount to the fiber is small, the epoxy resin layer formed on the surface of each single yarn is not sufficient, and the adhesion to the fiber cannot be obtained. On the other hand, when the amount of the epoxy compound is large, the single yarns are strongly focused by the formed epoxy resin, resulting in a cord having poor wear resistance. Therefore, the adhesion amount to the fiber surface is preferably 0.05 to 5.0% by weight, more preferably 0.2 to 5.0% by weight.

  Moreover, it is preferable that the resin film containing a polyepoxide compound also contains a rubber latex component. When the resin coating on the fiber surface is partially impregnated inside the fiber bundle, if the constraint between the single yarns is too strong, the degree of freedom of the single yarns is lost and the wear resistance is considered to be reduced. Therefore, the resin film can be softened by adding a flexible rubber latex component to the resin film. Examples of rubber latex components used include hydrogenated acrylonitrile-butadiene rubber latex (hydrogenated nitrile rubber latex), acrylonitrile-butadiene latex (nitrile rubber latex), isoprene rubber latex, urethane rubber latex, styrene-butadiene rubber latex, and vinylpyridine. -Styrene-butadiene rubber latex, chloroprene rubber latex, butadiene rubber latex, chlorosulfonated polyethylene latex, and the like, which are used alone or in combination. In particular, it is optimal to use a vinylpyridine / styrene / butadiene terpolymer latex having high affinity with the fiber surface. The amount of the latex component in the resin coating is preferably 20% by weight or more, and the optimum range is 20 to 80% by weight.

  More preferably, the organic fiber cord for reinforcing a friction material of the present invention has a resorcin / formalin / latex (RFL) resin film in the outer layer of the resin film containing the epoxy compound. Resorcin / formalin / latex (RFL) resin has high chemical affinity with both the epoxy compound of the inner layer and the thermosetting resin that is the base material of the friction material, and improves the adhesion between the organic fiber cord and the friction material. When the friction material is worn, the organic fiber cord having excellent wear resistance and the base material of the friction material are integrated to improve the stabilization of the wear resistance and the friction coefficient.

  Resorcin / formalin / rubber latex (RFL) is preferably used in which the molar ratio of resorcin to formaldehyde is in the range of 1: 0.6 to 1: 8, more preferably 1: 0.8 to 1: It is used in the range of 6. If the amount of formaldehyde added is too small, the crosslink density of the resorcin / formalin condensate will decrease and the molecular weight will decrease, and the adhesive layer cohesive force will decrease, resulting in a decrease in adhesion and bending fatigue. In addition, if the amount of formaldehyde added is too large, the resorcin / formalin condensate becomes hard due to an increase in the crosslinking density, the affinity with the adherend substrate tends to be inhibited, and the adhesiveness tends to decrease. The compounding ratio of resorcin / formalin and rubber latex is preferably a solid content ratio of resorcin / formalin: rubber latex (RFL) in the range of 1: 3 to 1:16, particularly 1: 4 to Those in the range of 1:10 are preferably used. If the ratio of the rubber latex is too small, the adhesive force tends to decrease because there are few double bonds that contribute to adhesion to the adherend substrate. On the other hand, if the ratio of the rubber latex is too large, the adhesive film is sufficient. Since the strength cannot be obtained, the adhesive strength and durability tend to be reduced, and the adhesiveness of the organic fiber cord that has been subjected to the adhesion treatment is remarkably increased, and the processability such as cam-up and handling is reduced in the adhesion treatment process. There is a fear. As the resorcin to be used, a resorcinol-formalin initial condensate pre-oligomerized or a polynuclear chlorophenol-based resorcin-formalin condensate obtained by oligomerizing chlorophenol and resorcin with formalin can be used alone or in combination as necessary. Also good. As described above, the rubber latex used here is hydrogenated acrylonitrile-butadiene rubber latex (hydrogenated nitrile rubber latex), acrylonitrile-butadiene latex (nitrile rubber latex), isoprene rubber latex, urethane rubber latex, styrene- There are butadiene rubber latex, vinylpyridine-styrene-butadiene rubber latex, chloroprene rubber latex, butadiene rubber latex, chlorosulfonated polyethylene latex and the like, which are used alone or in combination. In particular, a resorcin / formalin / rubber latex containing a nitrile rubber latex and / or a hydrogenated nitrile rubber latex having a high affinity with the epoxy compound on the fiber surface and a high affinity with the base material of the friction material is preferable. .

  In addition, a crosslinking agent can be used in combination with the resorcin / formalin / latex (RFL). Preferred examples of the crosslinking agent to be added include amines, ethylene urea, blocked isocyanate compounds, etc., but blocked isocyanate compounds are preferably used in view of the stability with time of the treatment agent and the interaction with the pretreatment agent. be able to. The isocyanate compound is preferably selected from aromatic diphenylmethane diisocyanate, toluene diisocyanate, aliphatic hexamethylene diisocyanate, and the like. More preferably, it is recommended to use diphenylmethane diisocyanate which is excellent in back adhesion with the epoxy compound on the fiber surface. More specifically, the blocked isocyanate is preferably a blocked isocyanate of a dimethylpyrazole block, a methyl ethyl ketone oxime block, or a caprolactam block. Moreover, you may use a blocked isocyanate compound in combination of 2 or more types. The addition rate of a crosslinking agent such as a blocked isocyanate compound is 0.5 to 40% by weight, preferably 10 to 30% by weight, based on resorcin / formalin / rubber latex (RFL). Increasing the amount added usually improves the adhesion, but if the amount added is too large, the compatibility between resorcin / formalin / rubber latex (RFL) and the cross-linking agent tends to decrease and the adhesion tends to decrease. is there. The adhesion amount of the resorcin / formalin / latex (RFL) resin film is preferably 1-20% by weight, more preferably 2-10% by weight.

The fiber used in the present invention may be twisted or non-twisted. Also, even if one or more of the fibers are aligned and twisted (single twist) on one side in the S direction or Z direction, the fibers are aligned in the S direction or Z After applying a primary twist on one side of the direction, draw more than one of the above cords and apply an upper twist (Lang twist) in the same direction as the single twist direction, or an upper twist (various twist) in the opposite direction. Also good. As the twist is applied, the orientation of the single yarn is inclined, so that the initial tensile strength is lowered, while the unevenness is formed on the fiber surface, so that the adhesiveness is improved. Here, the number of twists is represented by a twist coefficient (TM) that can be expressed by the following formula (1), and in the case of single twist, a range satisfying TM = 0.1 to 5.0, more preferably 0.5 to 3.0. In the case of various twists, the TM of the lower twist and the TM of the upper twist satisfy the range of 0.1 to 5.0, more preferably 0.5 to 3.0, respectively. It is preferable at the point which satisfy | fills bending fatigue property.
[Equation 1]
TM = T × √D / 1055
[However, TM: twist coefficient, T: number of twists (times / m), D: total fineness (tex). ]

  This calculation formula is generally used for a cotton spun yarn, and K = t / √N (K: twist coefficient, t: number of twists t / inch, N: cotton count). Is converted into the specific gravity of the aromatic polyamide fiber, the cotton count is converted into the fineness (tex), and recalculated. When TM is close to 1.0, the single yarn is inclined approximately 5.5 ° in the fiber axis direction, and the tensile strength is maximized by improving the alignment of the fiber bundle. The twisting applied to the fiber may be performed before or after the resin containing the epoxy compound or the resorcin / formalin / latex resin treatment.

  In order to attach the resorcin / formalin / latex resin to the fiber, means such as contact with a roller, application by spraying from a nozzle, or immersion in a solution can be employed. In order to control the amount of solid content attached to the organic fiber cord, as described above, it can be performed by means of squeezing with a pressure roller, scraping with a scrubber, etc., blowing off with air blowing, suction, beater means, In order to increase it, you may make it adhere several times.

  After immersing the fiber in a solution containing resorcin / formalin / latex resin, drying and heat treatment are preferably performed at a temperature of 100 ° C. to 250 ° C. for 60 to 300 seconds. More preferably, drying is performed at a temperature range of 100 to 180 ° C. for 60 to 240 seconds, and then heat treatment is performed at a temperature of 200 to 245 ° C. for 60 to 240 seconds. If this drying / heat treatment temperature is too low, adhesion to rubber tends to be insufficient, and if the drying / heat treatment temperature is too high, RFL promotes air oxidation at high temperatures and decreases the adhesive activity. There is a tendency to end up.

  The organic fiber cord for reinforcing a friction material of the present invention preferably has a bending strength of 40 MPa or less as measured by a three-point bending apparatus of JIS K 7017. More preferably, it is 20 MPa or less. The bending strength measured by the three-point bending machine of JIS K 7017 is connected to the hardness of the cord, and the use of hard resin or the resin impregnated inside the fiber bundle, the single yarn inside the fiber bundle is strong. You will be bound. As a result, in the case of a hard cord of 40 MPa or more, the single yarns are strongly focused, resulting in a cord having poor wear resistance. In order to obtain a bending strength of 40 MPa or less, in addition to selecting the composition of the epoxy compound on the surface of the single yarn and the resorcin / formalin / latex compound to be treated on the surface, the process of treating the resorcin / formalin / latex resin It is effective to soften the cord by gently bending the cord to break the excessively adhered resin film.

Such an organic fiber cord for reinforcing a friction material obtained by the production method of the present invention has greatly improved adhesion between a friction modifier and a base material containing a thermosetting resin, wear resistance, and friction coefficient stability. The friction material reinforcing organic fiber cord can be used as a reinforcing material to obtain a friction material having excellent physical properties.
In such a friction material, a thermosetting resin is impregnated into a base material containing the above-mentioned organic fiber cord for reinforcing a friction material and a friction modifier.

  Examples of the friction modifier include cashew dust, filler, diatomaceous earth, potassium titanate, barium sulfate, calcium carbonate, and silica powder. Examples of the thermosetting resin that can be used include phenol resins, melamine-modified, oil-modified, cashew-modified and other modified phenol resins, epoxy resins, and melamine resins.

  The friction material preferably contains a rubber composition in addition to the friction modifier and the thermosetting resin. The friction coefficient is stabilized by adding the rubber composition. In addition, resin containing epoxy compound and resorcin / formalin / latex resin treated on the fiber surface are excellent in adhesion to rubber in addition to adhesion to thermosetting resin. By including the object, the organic fiber cord and the base material of the friction material are more integrated, and the wear resistance and the stabilization of the friction coefficient are improved. As the rubber composition, NBR (acrylonitrile butadiene latex) rubber, SBR (styrene butadiene latex) rubber, natural rubber, or a mixture thereof can be used as the rubber composition. Moreover, it is preferable that carbon black, sulfur, and a vulcanization accelerator are included.

  The content of the organic fiber cord contained in the friction material is preferably 20 to 60% by weight. The content of the friction modifier is preferably 10 to 30% by weight, and the content of the rubber composition is preferably 10 to 30% by weight.

When manufacturing a clutch facing, first, an organic fiber cord is passed through a composition obtained by dissolving a friction modifier, a thermosetting resin, a rubber composition or the like in a solvent, and the composition is coated. Thereafter, the cord is wound into a product shape and then thermoformed to obtain a final clutch facing.
Such a clutch facing is suitably used as a clutch facing which is greatly improved in wear resistance and friction coefficient stability and is excellent in overall durability.

  Hereinafter, the present invention will be described with reference to examples. However, the examples are for illustrative purposes and the present invention is not limited thereto. In addition, evaluation in the Example of this invention was performed with the following measuring method.

(1) Bending strength The bending strength was measured with a three-point bending apparatus of JIS K 7017. The stress can be calculated by the following formula.
[Equation 2]
Bending strength = Bending load × 8 Lv / (π × D ³ )
[However, Lv: Edge span length, D: Code gauge. ]

(2) Peeling adhesive strength of the cord This shows the peeling adhesive strength between the friction material reinforcing organic fiber cord and the friction material base. The organic fiber cord is coated with the friction material base composition as shown in the following composition, then arranged in a width of 30 mm, and then molded at 180 ° C. under pressure for 30 minutes at a press pressure of 1 MPa. Was obtained, and a cord with a width of 30 mm was 200 mm / min. The force required to peel at a speed of 5 was expressed as an adhesive force.
(Composition composition)
Organic fiber cord: 50 parts Phenolic resin: 25 parts Calcium carbonate: 10 parts Nitrile rubber: 10 parts Carbon black: 2 parts Sulfur: 2 parts Vulcanization accelerator: 1 part

(3) Abrasion resistance, stability of friction coefficient The molded sample obtained in (2) is placed on a thrust cylinder type frictional wear tester manufactured by Orientec Co., Ltd., and is stainless steel under the conditions of a load of 20 kg and a peripheral speed of 1500 rpm. The amount of wear and the fluctuation width of the friction coefficient when rotating while pressing against the cylinder were measured. The lower the amount of wear, the better the wear resistance, and the smaller the fluctuation width of the friction coefficient, the higher the stability of the friction coefficient.

[Example 1]
Sorbitol-based polyepoxide compounds (SR-SEP manufactured by Sakamoto Pharmaceutical Co., Ltd.), ε-caprolactam blocked MDI (S3 manufactured by Meisei Chemical Co., Ltd.), and vinylpyridine / styrene / butadiene terpolymer latex (Pyratex manufactured by Nippon A & L Co., Ltd.) Were mixed at a ratio of 30% by weight, 30% by weight, and 40% by weight, respectively, to obtain a mixed solution having a total solid content of 10% by weight (treatment agent (1)).
An initial condensate having a resorcin / formalin (R / F) molar ratio of 1 / 0.6 and a solid concentration of 65% by weight is dissolved under alkaline conditions to obtain a 9% by weight aqueous solution. 99 parts by weight and 104 parts by weight of nitrile rubber latex latex (Nipol LX1562 from Nippon Zeon Co., Ltd.) and water are added to 57 parts by weight of the 9% resorcin / formalin aqueous solution, respectively. To this solution was added 3 parts by weight of formalin and 30 parts by weight of a 33% by weight acetoxime blocked diphenylmethane diisocyanate dispersion (DM 6011 manufactured by Meisei Chemical Industry Co., Ltd.), and aged for 48 hours. An agent was obtained (treatment agent (2)).

  After aligning two 3400 dtex / 2000 filament copolyparaphenylene-3,4'-oxydiphenylene terephthalamide fibers, twisting in the Z direction with a twist coefficient of 2.0 (8.0 times / 10 cm), A twisted cord was obtained. The cord was immersed in the treatment agent (1) using a contributor processing machine (CA Ritzler Co., Ltd., tire cord processing machine), then dried at a temperature of 130 ° C. for 2 minutes, and subsequently 240 ° C. Heat treatment was performed at a temperature for 1 minute, followed by immersion in the treatment agent (2), followed by drying at a temperature of 170 ° C. for 2 minutes, followed by a heat treatment at a temperature of 240 ° C. for 1 minute. The obtained cord had 4% by weight of the treating agent (1) and 5% by weight of the treating agent (2) as the solid content of the treating agent. The obtained treatment cord was evaluated for bending strength, peel adhesion to the friction material substrate, wear resistance of the molded body, and friction coefficient stability. The results are summarized in Table 1.

[Example 2]
The treatment was performed in the same manner as in Example 1 except that the rubber latex used in the treatment agent (2) was changed from nitrile rubber latex to nylpyridine / styrene / butadiene terpolymer latex (Pyratex, manufactured by Nippon A & L Co., Ltd.). Table 1 summarizes the performance evaluation of the fiber cords obtained.

[Example 3]
For treatment agent (1), vinyl pyridine / styrene / butadiene terpolymer latex was not used, but sorbitol-based epoxide compound and ε-caprolactam blocked MDI were mixed at a ratio of 50% by weight and 50% by weight, respectively. The treatment was carried out in the same manner as in Example 1. Table 1 summarizes the performance evaluation of the fiber cords obtained.

[Example 4]
The treatment was performed in the same manner as in Example 1 except that the treatment agent (2) was not treated with resorcin / formalin / latex (RFL). Table 1 summarizes the performance evaluation of the fiber cords obtained.

[Comparative Example 1]
Table 1 summarizes the performance evaluation results when fiber cords that are not bonded and do not contain an epoxide compound are used.

  Examples 1 to 4 of the present invention are cords that satisfy the wear resistance and the stability of the friction coefficient as compared with the comparative example.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness with a friction material base material is improved significantly, the organic fiber cord which leads to the abrasion resistance of a friction material, and the stability improvement of a friction coefficient can be provided, and a subject is in a conventional durability. It can be suitably used as a friction material such as the existing clutch facing.

Claims (8)

  An organic fiber cord for reinforcing a friction material, comprising a resin film containing an epoxy compound on a surface of a yarn.   2. The organic fiber cord for reinforcing a friction material according to claim 1, wherein the resin coating containing an epoxy compound contains a rubber latex component.   The organic fiber cord for reinforcing a friction material according to claim 1 or 2, wherein a resorcin-formalin latex (RFL) resin film is present in the outer layer of the resin film containing an epoxy compound.   The organic fiber cord for reinforcing a friction material according to any one of claims 1 to 3, wherein the yarn is made of an aromatic polyamide fiber.   The organic fiber cord for reinforcing a friction material according to any one of claims 1 to 4, wherein a bending strength measured by a three-point bending apparatus of JIS K 7017 is 40 MPa or less.   The organic fiber for reinforcing a friction material according to any one of claims 3 to 5, wherein the resorcin-formalin latex is a resorcin-formalin rubber latex containing a nitrile rubber latex and / or a hydrogenated nitrile rubber latex latex. code.   The aromatic polyamide fiber cord for reinforcing a friction material according to any one of claims 4 to 6, wherein the aromatic polyamide fiber is a copolyparaphenylene 3,4'-oxydiphenylene terephthalamide fiber.   A clutch facing comprising a base material containing the organic fiber cord for reinforcing a friction material according to any one of claims 1 to 7 and a friction modifier, impregnated with a thermosetting resin.