JPH0243787B2 - MASATSUZAI - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a friction material useful for use in automobile brake linings, disk pads, clutch facings, and power transmission mechanisms of various power machines. More specifically, it is a friction material containing a pulp-like substance of an aromatic polymer having a specific structure and heat resistance. One of the objects of the present invention is to provide a friction material that can eliminate the drawbacks of conventional friction materials mainly made of asbestos, such as a rapid decrease in the coefficient of friction at high temperatures (fade phenomenon) and an increase in the coefficient of friction. Another objective is to provide a friction material with improved mechanical strength (for example, rotational fracture strength in clutch facings) at high temperatures. Another objective is to provide a friction material that is superior to conventional friction materials that mainly contain asbestos, even when asbestos, which is currently becoming a problem in terms of occupational health and hygiene, is not used. In recent years, as vehicles have become larger and faster, and their operating conditions have become more severe, the performance required of brake linings, disk pads, clutch facings, etc. has become increasingly sophisticated. In other words, it is not only necessary to have a high friction coefficient during sliding, but also to have a stable value in response to changes in the temperature, speed, pressure, etc. of the sliding surface, and also to have a long life and a high friction coefficient. Many performance requirements are required, including no abnormal noise during operation and good heat resistance. Currently, asbestos is mainly used as the fiber component that makes up friction materials, but friction materials made mainly of asbestos suffer from a rapid drop in the coefficient of friction at high temperatures (fade phenomenon) and an increase in the coefficient of friction. This is a major drawback, and it is becoming impossible to meet the high-level demands mentioned above. Various proposals have been made to compensate for these drawbacks of friction materials manufactured mainly from asbestos, and for example, it is known to use a certain type of aromatic polyamide fiber as a fiber component constituting the friction material. . For example, JP-A-53-
Publication No. 130742 discloses the use of polymetaphenylene isophthalamide fibers together with glass fibers, and we have also disclosed in Japanese Patent Application Laid-open No. 125239/1989, "Friction material based on fibrous material". The constituent fibers include aromatic polyamide fibers and pulp-like particles made of a heat-resistant polymer as a binder,
Furthermore, after adding a friction performance improver and making paper as a base material and impregnating it with phenolic resin,
Friction material molded by heating and pressurizing. '' and disclosed fibers made of polymetaphenylene isophthalamide and polyparaphenylene terephthalamide as examples of aromatic polyamide fibers. Moreover, as pulp-like particles made of a heat-resistant high molecular weight polymer, pulp-like particles made of polymetaphenylene isophthalamide have been disclosed. However, the above-mentioned Japanese Patent Application Laid-Open No. 53-130742 and
Although the friction material described in Publication No. 54-125239 has excellent friction properties and wear resistance at high temperatures, its mechanical strength at high temperatures (for example, rotational fracture strength in clutch facings) is still insufficient. However, there was a drawback that the degree of deterioration was large with use. In order to develop a friction material that maintains excellent friction properties and friction resistance at high temperatures and has improved mechanical strength at high temperatures, we continued to study aromatic polyamides (1 ) A pulp-like material obtained from an aromatic polyamide having a specific structural unit has superior chemical resistance such as alkali resistance and acid resistance compared to polymetaphenylene isophthalamide and polyparaphenylene terephthalamide; (2)Friction materials made by blending pulp-like substances with excellent chemical resistance obtained from aromatic polyamides having the above-mentioned specific structural units not only have excellent friction properties and wear resistance at high temperatures. about,
They discovered that it also has excellent mechanical strength and completed the present invention. That is, the present invention provides a copolymer selected from the group consisting of aromatic polyether amide, aromatic polysulfamide amide, aromatic polysulfonamide, aromatic polymethylene amide, aromatic polyamine amide, and copolymers thereof. pulpy substance,
It is a friction material made of one kind or a combination of two or more kinds. Polymer The pulp-like material used in the present invention is obtained from a polymer mainly composed of repeating units represented by the following formulas (1) to (4). Ar ₁ , Ar 2 , and Ar 3 in formulas (1), ( ₂ ), and ( ₃ ) may be the same or different, and are aromatic carbocyclic residues in which bond chains extend in the same or parallel axes. represents groups, aromatic heterocyclic residues which must be bonded by the ring atoms representing the maximum spacing, and combinations thereof. Aromatic carbocyclic residues in which bond chains extend coaxially include, for example, 1,4-phenylene, 1,4-
Naphthylene, etc., and aromatic carbocyclic residues with bond chains extending in the parallel axis direction are, for example, 1,5
- Naphthylene, 2,6-naphthylene, etc. In addition, aromatic heterocyclic residues bonded by ring atoms representing the maximum spacing are, for example, 2,5-
Pyridylene,

【formula】

【formula】

【formula】

[Formula] etc. Furthermore, what is the combination of an aromatic carbocyclic residue whose bonding chain extends in the coaxial direction or in the parallel axis direction and an aromatic heterocyclic residue which must be bonded by the ring atoms representing the maximum spacing? For example, 4,4'-biphenylene,

【formula】

【formula】

【formula】

【formula】

etc. can be mentioned. The aromatic residue is -N=N-, -N=CH-, -
They may be bonded to each other by a group selected from the group consisting of CH=CH-, -C≡C-, for example,

【formula】

【formula】

【formula】

[Formula] etc. Furthermore, R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ in formulas (1) to (4) may be the same or different, and represent an alkyl group having 5 or less carbon atoms and a hydrogen atom. As the alkyl group having 5 or less carbon atoms, a methyl group,
Examples include ethyl group, propyl group, butyl group, pentyl group, etc., but methyl group is preferable. Ar ₄ and Ar ₅ in formula (4) may be the same or different,
Selected from paraphenylene group and metaphenylene group. Y in formula (4) is a divalent group, -O-, -S
−, −SO ₂ −,

【formula】 【formula】

A group selected from [Formula]. R ₆ , R ₇ and R ₈ are the same as R ₁ to _{R 5} above, and are preferably a hydrogen atom or a methyl group. Y is preferably -O-, -S-,

【formula】

[Formula] -CH ₂ -, most preferably -O-. A substituent may be bonded to the carbon atom of the above aromatic carbocyclic residue and aromatic heterocyclic residue. For example, halogen groups (e.g. chlorine, bromine, fluorine), lower alkyl groups (e.g. methyl, ethyl,
isopropyl group, normal propyl group), lower alkoxy group (e.g. methoxy group, ethoxy group),
Examples include cyano group, acetyl group, nitro group, etc.
Among these, chlorine and methyl groups are preferred. Incidentally, the fibers used in the present invention mainly have the above formulas (1) to
It is made from a polymer consisting of repeating units represented by (4), and the function of the number of moles of these repeating units is essentially (1) + (4) = (2), and (1) + ( 2)+(3)+(4
)
= 100 mol%, (3) = 0 to 90, and (4) =
It is 50 to 5 mol%. Preferably (4) is 30 to 10 mol%. The polymer can be obtained by reacting diamines, dicarboxylic acid derivatives, and aminocarboxylic acid derivatives corresponding to the repeating units represented by (1) to (4) above in a predetermined ratio. As the dicarboxylic acid derivative, it is preferable to use a dicarboxylic acid halide, particularly a dicarboxylic acid chloride. As the aminocarboxylic acid, it is preferable to use an aminocarboxylic acid halide hydrohalide salt, for example, aminocarboxylic acid chloride hydrochloride. Polymers can be obtained from these monomers by polymerization using known polymerization methods such as melt polymerization, solid phase polymerization, interfacial polymerization, and solution polymerization. Among these, solution polymerization is preferred. When producing a polymer, various additives can be added before, during, or after polymerization. Examples of additives include inorganic compounds such as lithium chloride, lithium carbonate, calcium oxide, calcium hydroxide, and chloride to neutralize hydrohalides produced as by-products of the polymerization reaction and/or to facilitate dissolution of the polymer. Examples include calcium and calcium carbonate. Furthermore, a terminal stopper, a light stabilizer, a crosslinking agent, etc. can be added as necessary. Pulp-like material The pulp-like material referred to in the present invention is a 1 to 10 mm, preferably 2 mm, hot drawn fiber produced from the above polymer.
After cutting to ~8mm, e.g. Disccliff Einer,
Fibrillated fibers obtained by beating and/or shearing with a beater etc. and polymers in a solvent as described in Japanese Patent Publication No. 35-11851 and Japanese Patent Publication No. 37-5732, These are so-called fibrids obtained by introducing a dissolved solution into a precipitant that is being stirred at high speed and causing it to precipitate as fine particles. These pulpy substances have numerous tentacle-like protrusions that can mechanically entangle with each other or with other particles, so there is no slippage at the interface between the pulpy substance and other components in the friction material. This makes it possible to obtain an ideal reinforcing effect without causing any phenomena. Although it is possible to obtain the objective friction material of the present invention even when a pulp-like substance called so-called fibrillated material is used, it is preferable to use the fibrillated fibers as the pulp-like substance to give more preferable results. . Furthermore, a pulp-like substance called fibrid and fibrillated fibers can be mixed together for use. The amount of pulp-like material in the friction material is an important factor in developing the mechanical properties, friction performance, etc. of the friction material, and is 5 to 70% by weight, preferably 10 to 50% by weight. The production of the raw material fibers used to make the fibrillated fibers and the properties of the raw material fibers will be explained next. The raw material fibers used to make the fibrillated fibers used in the present invention are obtained by defoaming and filtering a solution in which the above-mentioned polymer is dissolved, then spinning it into an aqueous coagulation solution, washing, drying, and hot stretching. You can get it. As the solvent for the polymer, aprotic amide polar solvents such as tetramethylurea, hexamethylphosphoramide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N,N-dimethylformamide are preferred. The spinning of the polymer solution may be carried out in a coagulating liquid, or it may be carried out by a dry jet wet spinning method, in which the polymer solution is first spun into a gas and then introduced into a coagulating liquid. A dry jet wet spinning method is preferably used. Further, the hot stretching is preferably carried out at a temperature of 250° C. or higher and 600° C. or lower at a stretching ratio of 2 times or more. Linear aromatic polyamides, such as Kevlar, which has high strength and high modulus, are dried after spinning and used as friction materials without heat treatment, or after spinning and drying. For example, it may be used as a friction material after being heat-treated at a temperature of 200°C or higher, generally 300°C or higher, under tension or in a relaxed state to improve its strength and modulus. However, the chemical resistance of linearly coordinated aromatic polyamide fibers is inferior to that of fibers made of aromatic polyamide having a specific structure used in the present invention. For example, fibers made of linearly coordinated aromatic polyamides such as polyparaphenylene terephthalamide can only be subjected to relaxation heat treatment at a temperature of 200°C or higher or tension heat treatment at a draw ratio of 1.5 times or less. Fibers made of aromatic polyamide having a structure are hot-stretched at a temperature of 200° C. or higher by a factor of 2 times or more, preferably 5 times or more, and exhibit high strength and modulus as well as high chemical resistance. For example, in a 10% by weight aqueous solution of caustic soda at 95°C.
Comparing the strength retention rate when soaked for 10 hours,
Polyparaphenylene terephthalamide fiber (Kevlar-29), a linear aromatic polyamide
The strength retention rate of the fiber used in the present invention is 95%, whereas the strength retention rate of the fiber used in the present invention is about 20%, and the strength retention rate of the fiber used in the present invention is about 60% when the fiber (Kevlar-49) is further subjected to tension heat treatment.
That's all, and it's very good. In addition, the strength retention rates when immersed in a 20% by weight aqueous sulfuric acid solution at 95°C for 20 hours were as follows. Kevlar-29 15% Kevlar-49 50% Fiber used in the present invention 97% The excellent chemical resistance of the fiber used in the present invention is due to the composition of the polymer constituting the fiber and the 200%
It is developed by hot stretching to double or more at a temperature of ℃ or higher. On the other hand, friction materials such as the disc pads of automobile disc brakes are used by adhering them to a reinforcing back metal, but this prevents the problem of the disc pad peeling off from the back metal due to rust generated from the adhesive surface between the disc pad and the reinforcing back metal. In order to achieve this, the composition of the disk pad is sometimes chosen to exhibit some degree of alkalinity. There is also a known method of producing a paper-like material using a wet papermaking method and processing this paper-like material to produce, for example, a friction material for clutch facings, but in this case,
Sulfate band is often used as a fixing agent in order to reduce the leakage of fillers, friction performance modifiers, etc. from the entire paper mesh. In this case, the clutch facing friction material may become acidic. Therefore, it is of great significance to use the fibrillated fiber of the present invention, which has excellent chemical resistance such as alkali resistance and acid resistance, as the fibrillated fiber constituting the friction material, especially at high temperatures. A friction material with excellent mechanical properties can be obtained. The single yarn fineness of the raw material fiber used in the present invention is
It is 0.5 to 15 denier, preferably 1 to 10 denier. When producing the friction material of the present invention, a pulp-like substance and other fibers may be mixed and used as necessary. In this case, other fibers include asbestos,
Inorganic materials such as glass fiber, ceramic fiber, silica fiber, alumina fiber, potassium titanate fiber, titanium oxide fiber, bauxite fiber, kyanite fiber, boron-based fiber, magnesia fiber, rock wool, mineral wool, metal fiber, gypsum fiber, dawsonite fiber, etc. Fibers include non-melting organic fibers such as cotton, wool, hemp, rayon, aromatic polyamide fibers, carbon fibers, and phenol fibers. Among these other fibers, it is preferable not to use asbestos from the viewpoint of occupational hygiene, but it may be used as long as it does not impair the frictional properties and mechanical properties, especially at high temperatures. When mixing the pulp-like substance used in the present invention with other fibers, the mixing ratio should be determined depending on the application of the friction material,
It should be selected according to the required characteristics. Manufacture of Friction Material When manufacturing the friction material of the present invention, known methods can be employed. For example, a mixture of a fiber component, a friction performance modifier, and a thermosetting resin is pre-molded, placed in a predetermined mold, and molded at a pressure of 50 kg/cm ² or higher, preferably 100 kg/cm 2 or higher, at a molding temperature of 130 to 100 kg/cm ² . 290℃, preferably 170
Mold at ~250℃. After the molded product is cooled, it is finished using a polishing machine. After molding again,
Heat treatment may be performed for the purpose of completing the curing reaction of the thermosetting resin in the state taken out from the mold. In particular, when manufacturing clutch facings, after uniformly mixing and dispersing the pulp-like material and friction performance modifier in water, the process is followed by paper making, impregnation with thermosetting resin, pre-drying, pressure and heat molding, and crank press. There is also a method of manufacturing through a process such as punching. Examples of the friction performance modifier used in producing the friction material of the present invention include the following. Alumina, silica, talc, kaolin, mica,
Metal oxides such as chromium oxide, magnesium oxide, and titanium oxide; Metals such as copper or copper alloys, zinc, iron, and aluminum; Inorganic compounds such as barium sulfate, quicklime, calcium phosphate, calcium fluoride, and carborundum; Clay, curbstone Minerals such as , mullite, and chromite; abrasive friction performance modifiers such as ceramic powder and hardened resin particles called friction dust; non-abrasive friction performance modifiers such as rubber powder; carbon black; graphite, etc. Conditioners can be used.
Further, thermosetting resins used in the production of the friction material of the present invention include phenolic, melamine, urea, epoxy, and polyimide resins, and phenolic resins are often used. In the case of phenolic resins, liquid or solid products such as novolac type phenolic resins, resol type phenolic resins, and modified phenolic resins such as melamine-modified phenolic resins, cresol-modified phenolic resins, and cashew-modified phenolic resins can be used. Next, in manufacturing the friction material of the present invention, the blending ratios of the pulp-like material, friction performance modifier, and thermosetting resin will be described. The proportion of pulp-like substances in the total formulation is 5 to 5.
70% by weight, preferably 10-50% by weight. Similarly, the total amount of frictional performance modifiers is 1 to 40% by weight, preferably 5 to 20% by weight. Further, the amount of the thermosetting resin is 10 to 40% by weight, preferably 15 to 35% by weight. The present invention will be explained in detail with reference to Examples below. Incidentally, unless otherwise specified, parts or percentages are based on weight. Example 1 N-methyl-2
- Polymerization in pyrrolidone followed by neutralization with calcium hydroxide until the concentration of aromatic polyetheramide is 6
% spinning solution was obtained. This solution has a pore size of 0.2 mm.
It was once extruded into the air through a spinning nozzle with 1,000 holes, passed through an air layer of about 2 cm, and then introduced into an aqueous coagulation solution. After thoroughly washing in a water washing bath, it was dried with a drying roller. . The dried fibers
Stretched 11.0 times on a hot plate at 510℃, coated with oil and wound, single yarn fineness 1.5 denier, tensile strength 430
A fiber with ^an initial modulus of 7.5×10 ³ Kg/mm ² was obtained. The fiber thus obtained was cut into a length of 7 mm and 1.0
Dispersed in water to a concentration of %. This aqueous dispersion containing aromatic polyetheramide fibers was repeatedly passed through Disc Cliff Eye Iner (manufactured by Kumagai Riki Kogyo) five times to fibrillate the fibers to obtain a pulp-like material. Next, the pulp-like material was over-dried and used for manufacturing a friction material. The friction material was manufactured as follows. (1) The above aromatic polyether amide pulp material
30 parts (2) Glass fiber (diameter 10 μ, length 5 mm) 10 parts (3) Phenol resin 20 parts (4) Cashew powder 15 parts (5) Barium sulfate 10 parts (6) Brass powder 5 parts (7) Powdered inorganic material Filling material 10 parts The above (1) to (7) were dispersed in water, mixed uniformly, filtered and dried, and the resulting mixture was preformed, then placed in a mold, and heated at 170°C, 250Kg/cm ² , 5 After compression molding for 1 minute, heat treatment was performed in a hot air oven at 190°C for 5 hours to complete the curing reaction of the phenol resin. The performance of the friction material obtained by taking it out from the mold, cooling it, and polishing it is shown in Table 1, and all were good.

[Table] In Table 1, the bending strength of the friction material at 200℃ is
After heat deterioration treatment for 24 hours, cool to room temperature and JIS
Although measured using the method specified in D4311, 200
Even after heat deterioration treatment at -24 hours, it exhibited a bending strength of 6.7 Kg/mm ² and had sufficient mechanical strength. Comparative Example 1 A friction test was carried out in exactly the same manner as in Example 1, except that polyparaphenylene terephthalamide fibers (du Pont, Kevlar) were used instead of the aromatic polyetheramide pulp material. I got the material. The friction coefficient and wear rate of the friction material thus obtained were almost the same as in Example 1, and were good.
The bending strength measured in the same manner as in Example 1 was 4.3 Kg/mm ² , which was poor. Example 2 Polymerization was carried out in N-methyl-2-pyrrolidone using 15 mol% of paraphenylene diamine, 15 mol% of 3,4'-diaminodiphenyl ether, 20 mol% of chlorparaphenylene diamine, and 50 mol% of terephthalic acid chloride. Thereafter, the solution was neutralized with calcium hydroxide to obtain a spinning solution with a polymer concentration of 6%. Using this solution, fibers were obtained in exactly the same manner as in Example 1. The obtained fiber had a single yarn fineness of 1.5 denier, a tensile strength of 395 Kg/mm ² , and an initial modulus of 9.7×
It was ¹⁰³ Kg/ ^mm2 . Thereafter, a pulp-like substance was produced in exactly the same manner as in Example 1, and a friction material was further produced. The performance of the obtained friction material was almost the same as that of Example 1 and was good. Example 3 N-methyl- was added to the spinning solution obtained in Example 1.
Dilute by adding 2-pyrrolidone to a polymer concentration of 1.5.
% solution. On the other hand, as a precipitant, N-methyl-2-pyrrolidone and water were mixed to prepare a precipitant having an N-methyl-2-pyrrolidone concentration of 20%. The precipitation device consists of a combination of a stator with a gusset and a two-blade rotor in the form of turbine blades, and is equipped with an inlet for the precipitant and polymer solution, and an outlet for the pulp-like substance slurry after precipitation. Using a type continuous precipitator, the polymer solution and precipitant were simultaneously supplied at a flow rate of 5 kg/min and 15 kg/min, and the pulp-like substance slurry was taken out from the outlet. The resulting slurry of pulp-like material was placed in a Nutstier-type filter and filtered and washed to obtain a pulp-like material called a so-called fibrid of aromatic polyetheramide. A clutch facing was created using this pulp material as described below. (1) 20 parts of the above pulp-like substance (2) 10 parts of the aromatic polyetheramide fiber (1.5 denier, 7 mm) used in Example 1 (3) 5 parts of co-copper fiber (4) Ceramic fiber (Kao Wool manufactured by Isolite Industries) ) 5 parts (5) Powdered inorganic filler 10 parts (6) Band sulfate 3 parts After dispersing the above (1) to (6) in water to a concentration of 0.3%, paper was made using a Fourdrinier paper machine. Dry and proceed with (1) above
A sheet-like product consisting of (6) was obtained. 50 parts of the sheet-like material was impregnated with a mixture of 20 parts of phenolic resin and 30 parts of barium sulfate, and the mixture was heated to
Dry at 110°C. Next, this was cut into a tape shape with a width of 20 mm using a slitter, wound into a spiral shape, and then placed in a mold and heated to a temperature.
It was pressed at 160° C. under a pressure of 200 kg/cm ² for 6 minutes, taken out, heated at 190° C. for 60 minutes, and then polished to obtain a clutch facing. The performance of the clutch facings thus obtained is shown in Table 2, and all were excellent.

[Table] In Table 2, the friction coefficient and wear rate are
Conducted based on JISD4311. In addition, the rotational breaking strength is 200 mm in outer diameter and 130 mm in inner diameter.
After leaving a 3.5mm thick sample at 200℃ for 24 hours, the temperature was 200℃.
It was rotated at increased speed in an atmosphere at ℃, and the number of rotations at the time of failure was measured. Comparative Example 2 In Example 3, the procedure was carried out in the same manner as in Example 1 except that the pulp-like material of polyparaphenylene terephthalamide (Kevlar from du Pont) was used in place of the pulp-like material of aromatic polyetheramide and the fibers, respectively. Example 3 except that the fibers were used
Clutch facing was obtained in the same manner. The rotational breaking strength of the obtained clutch facing (measured in the same manner as in Example 3) was 15000 rpm.
and was inferior. Comparative Example 3 A clutch facing was obtained in exactly the same manner as in Example 3, except that long-fiber asbestos was used instead of the aromatic polyetheramide pulp and fibers. The performance of the resulting clutch facings (measured in the same manner as in Example 3) is shown in Table 3.

[Table] The friction coefficient at 250°C, wear rate at 200°C and 250°C, and rotational fracture strength were not satisfactory values.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the copolymerization composition of the wholly aromatic polyetheramide copolymer according to the present invention.

Claims (1)

[Scope of Claims] 1. A friction material comprising one or more pulp-like substances made of a copolymer of aromatic polyether amide. 2 Aromatic polyetheramide has the general formula [In the formula, A and B may be the same or different, -
COX (X is a halogen atom), -NH ₂ , -NH ₂ HX (X
is the same as above), [Formula] (R is an alkyl group having 5 or less carbon atoms), [Formula] (X and R are the same as above). ] General formula [In the formula, A and B are the same as above] General formula A-Ar-B [In the formula, A and B are the same as above, and Ar is an aromatic aromatic whose bonded chains both extend in the same or parallel axes. Represents family carbocyclic residues, aromatic heterocyclic residues connected by the ring atoms representing the largest spacing, and combinations thereof. ] One or more of the compounds represented by the total number of moles of the group represented by -COX (X is the same as above) and -
NH ₂ , -NH ₂ HX, [Formula] [Formula] (X and R are the same as above) so that the total number of moles of the group is substantially equal, and the general formula [A and B are the same as above] An aromatic polyether amide, characterized in that the reaction is carried out so that at least 7.5 mol% of the compound represented by the above is contained. Or, the repeating unit substantially has the following general formula [-NH-Ar ₁ -NH-CO-Ar ₂ -CO]-...(A) and/or [-NH-Ar ₃ -CO]-...(B) [ In the formula, Ar ₁ , Ar ₂ and Ar ₃ are aromatic carbocyclic residues, and Ar ₁ , Ar ₂ and Ar ₃ may be the same or different, It is a residue selected from. In the formula, X is one or more groups selected from the same or different halogen groups, alkyl groups, aralkyl groups, aromatic groups, alkoxy groups, acetyl groups, and cyano groups, and n is 1 to 3 groups. is an integer. Ar ₁ , Ar ₂ and Ar ₃ are each represented by formula (a) and/or (b) and/or formula (c), and Ar ₁ , Ar ₂ and/or
The copolymerization ratio expressed as the molar ratio of aromatic residues including Ar ₃ is the point P in the triangular diagram in Figure 1,
It is in the range surrounded by a rectangle obtained by sequentially connecting Q, R, and S with straight lines (range indicated by diagonal lines)]
The friction material according to claim 1, further comprising a pulp-like material which is an aromatic polyetheramide having an intrinsic viscosity of at least 1.5. 3. Claims 1 or 2, wherein the pulp-like material is a pulp-like material obtained by cutting hot drawn fibers of aromatic polyetheramide and then fibrillating them by beating and/or shearing action. Friction material as described. 4. The pulp material introduces a solution of aromatic polyether amide into a precipitating agent that is being stirred at high speed;
The friction material according to claim 1 or 2, which is a pulp-like material obtained by precipitation as fine particles.