JP3187256B2 - Aramid fiber cord for power transmission belt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aramid fiber cord used as a power transmission belt reinforcing cord. Particularly, the present invention relates to a belt having a form in which an aramid fiber cord for belt reinforcement is exposed from a side surface of the belt, such as a timing belt and a low edge V belt, is formed into a tubular shape, and is vulcanized. When forming a belt by cutting into a ring shape from the aramid fiber single thread from the aramid fiber cord exposed on the belt end surface cut in the fiber axis direction,
The present invention relates to an aramid fiber cord having good adhesion to a matrix rubber and excellent fatigue resistance.

[0002]

2. Description of the Related Art Aramid fiber cords generally have excellent properties such as strength, elastic modulus, dimensional stability, heat resistance and the like, so that rubber composites such as tires, belts and hoses used under severe conditions are used. Useful as an excellent reinforcing fiber.
In particular, due to its high specific strength and specific elastic modulus, aramid fiber cord is expected to increase in demand as a lightweight reinforcing fiber replacing steel and wire.

[0003] Generally, reinforcing fibers for composites such as tires, belts and hoses are used in the form of twisted cords by bonding. In general, the impregnation of the adhesive treated cord with the water-based adhesive or the solvent-based adhesive is insufficient. In particular, the impregnation property of the aqueous treatment agent is poor. When the adhesive-treated aramid fiber cord is used as a reinforcing fiber for a timing belt or a low-edge V-belt, it is formed into a tubular shape and vulcanized in advance. Subsequently, a belt was made by cutting the aramid fiber cord reinforced rubber composite formed in a cylindrical shape into a ring shape with a cutter, but because the adhesive was not sufficiently impregnated, the belt was exposed at the cut surface. Each single yarn constituting the fiber from the aramid fiber cord may protrude from the fray or the side surface of the belt, in which case the quality of the belt is significantly reduced. If the belt is operated as it is on a pulley, the single yarn frayed portion is rubbed by the pulley and the frayed single yarn scatters, or the fraying causes a decrease in the durability of the belt.

[0004] These drawbacks are prevented by the operation of mechanically removing or cutting each of the frayed single yarns during the belt production process. Productivity has declined significantly and has been a major obstacle to adapting aramid fiber cords in this area. Meanwhile, in order to improve such drawbacks of aramid fiber cords, advance aramid fibers treated with a treating agent such as rubber latex, but the fray of single yarn during cutting and anti Guko was attempted (JP-1 −
207480, JP-A-4-29644),
Satisfactory aramid fiber cord for power transmission belts can cause other defects, such as poor twisting properties of aramid fibers due to rubber latex treatment, lowering inherent strength, impairing adhesion and durability, etc. Could not be obtained. The present inventors have also proposed a method in which aramid fibers are treated in advance with a polyepoxide compound, treated with a treating agent containing RFL, twisted, and further treated by RFL-based treatment (JP-A-6-25977). Gazette, JP-A-6-259
No. 78, JP-A-6-207380), although the fraying property and the adhesiveness are remarkably improved, the strength and the fatigue resistance are lowered, leaving room for improvement.

Therefore, there is a demand for an aramid fiber cord in which an adhesive containing RFL is impregnated into an aramid fiber cord to balance the fraying property, strength and fatigue resistance. However, such a cord has not yet been obtained. Not.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the problems in the prior art by solving aramid fiber cords for power transmission belts, that is, exposed to belt end surfaces during belt molding. An object of the present invention is to obtain an aramid fiber cord that prevents fraying of a single yarn of aramid fiber, improves adhesion to a matrix rubber, and has good strength and good fatigue properties.

[0007]

According to the present invention, there is provided "(Claim 1) wherein a treatment liquid containing a polyepoxide compound containing two or more epoxy groups is impregnated in a substantially untwisted state at a temperature of 150 to 260.degree.
Aramid fiber heat-treated for 0 to 210 seconds is 1 ≦ K ≦ 5
(K = (T × D ^1/2 ) / 2874, K: twist coefficient, T: number of twists expressed in turns / m, D: single yarn fineness). After impregnating a treatment liquid containing formalin rubber latex (RFL) under vacuum and pressure conditions, heat-treating at 150 to 260 ° C. for 30 to 210 seconds, and further treating with a treatment agent containing RFL. Aramid fiber cord for power transmission belt. (Claim 2) The power transmission according to claim 1, wherein the rubber latex in the RFL is acrylonitrile butadiene (NBR) and / or hydrogenated acrylonitrile butadiene (H-NBR, a highly saturated copolymer rubber containing a nitrile group). Aramid fiber cord for belt. ".

The aramid fiber in the present invention is a fiber made of a polymer in which repeating units in which aromatic rings are bonded by amide bonds account for at least 80% or more of the whole.
Representative examples of fibers comprising these polymers or copolymers include polyparaphenylene terephthalamide, polymetaphenylene isophthalamide, and polyparaphenylene.
Conventionally known fibers made of aramid, such as 3,4 ′ diphenyl ether / terephthalamide, can be used.

The epoxy compound for treating the aramid fiber in advance without twisting is a compound containing at least two epoxy groups in one molecule in an amount of 0.2 g equivalent or more per 100 g of the compound, and ethylene glycol, glycerol, Reaction products of polyhydric alcohols such as sorbitol, pentaerythritol and polyethylene glycol with halogen-containing epoxides such as epichlorohydrin, resorcin / bis (4-hydroxyphenyl) dimethylmethane, phenol / formaldehyde resin, resorcin / formaldehyde resin, etc. Reaction products of polyhydric phenols and the above-mentioned halogen-containing epoxides, polyepoxide compounds obtained by oxidizing unsaturated compounds with peracetic acid or hydrogen peroxide or the like, that is, 3,4-epoxycyclohexene epoxide De, 3,4-epoxycyclohexylmethyl-3,4-epoxy cyclohexene carboxylate, bis (3,4-epoxy-6-methyl - cyclohexyl methyl) adipate, etc. can be mentioned. Among these, a reaction product of a polyhydric alcohol and epichlorohydrin, that is, a polyglycidyl ether compound of a polyhydric alcohol is particularly preferred because of excellent performance.

Such a polyepoxide compound is usually dissolved in a small amount of a solvent and used as an emulsified liquid or solution using a known emulsifier, for example, sodium alkylbenzenesulfonate, sodium salt of dioctylsulfosuccinate. Polyepoxide compounds include amine-based, imidazole-based curing agents or blocked isocyanates that are addition compounds of polyisocyanates with known blocking agents such as oximes, phenols, and caprolactam, and ethylene urea that is a reaction product of ethylene imine described below. Can be mixed and used.

For example, the mixing ratio of the polyepoxide compound (A) and the curing agent, blocked isocyanate or ethylene urea (B) is 0.05 ≦ (A) / [(A) +
(B)] ≦ 0.9 (weight ratio) is preferable. The concentration of the polyepoxy compound is from 0.1 to 5.0%. The total solid concentration is 1 to 30% by weight, preferably 3 to
It is used so as to be 20% by weight.

The above-mentioned treating agent containing a polyepoxide compound is usually mixed with an oil agent during the production of aramid fibers and adhered thereto, or independently adhered after the aramid fiber production. Solid adhesion amount to aramid fiber is 0.05 ~
5.0% by weight and adhered, 100-1%
Dry at 50 ° C. for 60-180 seconds, then 150-2
Treat at 50 ° C. for 30 to 210 seconds. Preferably 60-1
80 seconds.

The aramid fiber cords thus treated with the treating agent containing the polyepoxide compound are twisted within a range of 1 ≦ K ≦ 5 to obtain an aramid fiber cord.

[0014] The aramid fiber cord treated with the polyepoxy compound is then vacuum-bonded with a second treating agent, RFL (resorcin-formalin latex), a silicone-based treating agent and an adhesive containing an antioxidant or an antioxidant. -Impregnation is performed under pressure. That is, first, a certain amount of aramid fiber cord wound on a metal perforated bobbin is put into a metal vacuum / pressure impregnating apparatus, first, the pressure is reduced, and then the treating agent containing the RFL is introduced. The fiber cord is impregnated under reduced pressure. Then pressurize,
Improves impregnation of cord. After performing a vacuum / pressure impregnation process under a predetermined condition, the pressure is returned to normal pressure, and the pressure is further increased to remove a processing agent containing excess RFL.

The usual conditions of vacuum and pressure impregnation are adjusted to a degree of pressure reduction of 10 torr and a pressure of 20 kg / cm ² in the container. The depressurization condition for removing excess processing agent is 5 kg /
cm ² , but there are no restrictions on the vacuum and pressure conditions.

The RFL used here has a molar ratio of resorcinol to formaldehyde of 1: 0.1 to 1: 8, preferably 1: 0.5 to 1: 5, more preferably 1: 1 to 1: 1.
4 is used. The compounding ratio of resorcinol-formalin and rubber latex is 1: 1 to 1: in terms of solid content weight ratio.
15, preferably in the range from 1: 3 to 1:12. If the compounding ratio of the rubber latex is too high, the tackiness is significantly increased and the cohesive strength is also reduced, which adversely affects impregnation and adhesion. Conversely, if the mixing ratio of the rubber latex is too low, the cord becomes hard, and the strength and fatigue properties are reduced. As a type of rubber latex,
It is selected according to the rubber type of the adherend. For example, if the rubber of the adherend is CR, CR latex is used, and if NBR or H-NBR, NBR latex and / or hydrogenated NBR latex are used. For CSM, C
SM latex is often used. Of course, a mixture of these rubber latexes may be used.

The antioxidant or antioxidant is R
5.0 to 15.0% by weight of solid content is added to FL.

Examples of the type of antioxidant include hindered phenol compounds, amine compounds, phosphorus compounds and sulfur compounds. As a typical example, in a hindered phenol compound system, triethylene glycol bis [3-
(3-t-butyl-6-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2 , 4-Bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-
Butylanily-1,3,5-triazine, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-
4-hydroxyphenyl) propionate], 2,2-
Thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N , N'-Hexamethylenebis (3,5-di-t-butyl-4-hydroxy-
Hydroxycinnamamide), 1.3.5-trimethyl-
2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene and the like can be mentioned. In addition, hindered ferrites containing sulfur or phosphorus in the molecule
The no-le compound 2,2-thiobis (4-methyl -
6-t-butylphenol) and 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester. Representative examples of amine antioxidants include N, N'-di-sec-butyl-p-phenylenediamine, alkylated diphenylamine, and the like.

Examples of the antioxidant include aldehyde-amine reaction products. Representative examples thereof include a condensate of aldol and 1-naphthylamine, and 2,2 as a ketone-amine reaction product. , 4-trimethyl-1,2-dihydroquinoline polymers. N, N'-dinaphthyl-p is used as an amine compound.
-Phenylenediamine is a typical example. Phenol compounds include styrenated phenol, 2,6-di-t
-Butylmethylphenol, 2,2′-methylenebis (4-methyl-6-t-butylphenol), 4,4 ′
-Thiobis (3-methyl-6-t-butylphenol)
And so on.

After vacuum / pressure impregnation with a treatment agent containing RFL, the aramid fiber cord taken out of the metal vacuum / pressure impregnation processing apparatus is heated to 80 to 150 ° C. and 0.5 to 150 ° C.
After drying for 5 minutes, heat treatment is performed at 150 to 260 ° C. for 0.5 to 5 minutes to cure. The adhesion amount of RFL as the second treatment agent to the aramid fiber cord is 1 to 25%, preferably 5 to 25%.
Adjusted to 20%. If the adhesion rate is lower than 1%, when the aramid fiber cord is used as the reinforcing fiber of the power transmission belt, the single yarn exposed from the belt end face may be frayed. Conversely, if it is more than 25%, the strength and adhesiveness of the treated aramid fiber cord may decrease.

The RFL to be treated has a molar ratio of resorcinol to formaldehyde of from 1: 0.1 to 1: 8, preferably from 1: 0.5 to 4, similarly to RFL as the second treating agent.
It is used in the range of 1: 5, more preferably in the range of 1: 1 to 1: 4. Further, the mixing ratio of resorcinol-formalin and rubber latex is preferably in the range of 1: 1 to 1:15, more preferably 1: 3 to 1:12 in terms of solid weight ratio. As the type of rubber latex, RFL which is the second processing agent is used.
It is selected depending on the rubber latex used for
As shown in JP-B-57-21587, this RFL is represented by the following general formula (Chemical Formula 1) (wherein R 'is an aromatic or aliphatic hydrocarbon residue, and n is 0, 1 or 2). And a blocked isocyanate obtained by reacting an ethylene urea compound or an aromatic or aliphatic isocyanate with an oxime, phenol, caprolactam or the like.

[0022]

Embedded image

The ethylene urea compound is usually added in the form of an aqueous dispersion in an amount of 0.5 to 30% by weight based on RFL. Further, an aqueous dispersion of carbon black prepared by an ordinary method may be added in an amount of 0.5 to 5% by weight based on RFL. After being treated with RFL, it may be further treated with rubber glue containing the same type of rubber as the rubber matrix of the adherend.

After the above-mentioned RFL treatment, at 80 to 150 ° C.
After drying for 0.5 to 5 minutes, 150 to 260 ° C, 0.5 to 5
Heat treat for a minute and cure. The amount of RFL attached to the twisted cord is adjusted to 1 to 10% by weight.

After being treated with the polyepoxide compound containing two or more epoxy groups as described above, the aramid fiber cord having a predetermined number of twists is impregnated with a treatment agent containing RFL under predetermined vacuum and pressure conditions. The aramid fiber cord reinforced power transmission belt, which is formed from a composite of treated, dried and heat-cured cord and rubber, has a single aramid fiber thread that does not fray out from the end face and has improved adhesion to the matrix rubber. Of course, the fatigue resistance is remarkably improved. Regarding the improvement of the prevention of fraying, RFL is sufficiently impregnated into the cord by vacuum / pressure impregnation processing, and the epoxide compound previously treated on the aramid fiber and the impregnated RFL react with each other, resulting in high cohesion. It is presumed that a relatively soft film is formed, and at the same time, a single yarn of aramid fiber is covered with RFL one by one and adhered firmly, so that the frayability is improved. That is, by twisting the aramid fiber which has been epoxy-treated in advance, better alignment of single yarns can be obtained than in the case where the fiber is RFL-treated and twisted, thereby increasing the cord strength.
In addition, since the RFL is subjected to vacuum and pressure impregnation after twisting, the uniformity of the single yarn is maintained, and the elongation / compression strain during fatigue is uniformly applied and the stress is dispersed. It is thought that it leads to improvement of fatigue. Further, the antioxidant or anti-aging agent added to the RFL also contributes to preventing fatigue of the aramid fiber cord, which is a reinforcing fiber, by hardening the RFL during running of the belt, thereby leading to improvement in fatigue property. It is presumed that.

[0026]

According to the present invention, the aramid fiber cord which has been subjected to the vacuum / pressure impregnation processing according to the method of the present invention has a small decrease in strength, and the aramid fiber single yarn frays from the belt end face after forming the power transmission belt. In addition, the adhesion to the matrix and the fatigue properties are relatively good.

Hereinafter, the present invention will be described specifically with reference to examples.

In the examples, the cord strength, the fraying property, the cord peeling adhesive strength, the pull-out adhesive strength, and the strength retention during fatigue are values obtained as follows.

<Cord Strength> Using an Intesco 2005 type tensile test (manufactured by Intesco Corporation), a cord length was set to 250 mm between the chucks using a 4D air chuck, and the cord strength was measured at a pulling speed of 100 mm / min. 5
Times, and the average value was taken as the code strength.

<Fasting> Rubber sheet 2 about 2 mm thick
The above-mentioned fraying treatment is performed between the sheets, and then the aramid cords treated with the adhesive containing RFL are arranged in parallel and sandwiched.
The rubber was vulcanized at 150 ° C. for 30 minutes under a pressing pressure of 50 kg / cm ² to obtain a rubber sheet. This sheet was cut in the length direction of the cords arranged in the rubber using a cutter knife so that the end faces of the cords appeared on the cut surface. And
The state of the single yarn of the aramid fiber protruding from the end face was visually determined. Also, this end face is sandpapered (# AA-1).
50), and the frayed state of the single yarn was observed. The evaluation was good 良好 →→→ △ → × (poor).

<Cord Peeling Adhesive Strength> This shows the peeling adhesive strength between the treated cord and the rubber. 7 cords are buried near the surface of the rubber sheet, and pressurized at 150 ° C for 30 minutes for 50 minutes.
After vulcanizing with a pressing pressure of kg / cm ² , the two cords at both ends were removed, and the remaining five cords were removed from the rubber sheet at 200 mm / min. The force required for peeling at a speed of kg / kg
This is indicated by five lines.

<Pull-out adhesive force> This shows the shear adhesive force between the treated cord and the rubber. Embed the cord in a rubber block and pressurize at 150 ° C for 30 minutes, 50kg / c
vulcanized in a press pressure of m ^2, then the code from the rubber block 200 mm / min. And the force required for the drawing is expressed in kg / cm.

<Strength of retention during fatigue> A belt-type fatigue tester is used as a measure of fatigue resistance. A cord is sandwiched between two rubber sheets having a thickness of 2 mm, and 50 kg / cm ² at 150 ° C. for 30 minutes. The sheet obtained by vulcanization at a pressing pressure of 50 mm is cut into a belt shape of 50 mm width × 500 mm length, a load of 25 kg is applied, attached to a roller having a diameter of 20 mm, and reciprocated at 120 rpm in an atmosphere of 120 ° C. After repetition, the cord was taken out, the remaining strength was measured, and the strength retention during fatigue was determined.

[0034]

Example 1, Comparative Examples 1 and 2 First, an adhesive treatment agent was prepared as follows. That is, Denacol EX-313 (glycerin diglycidyl ether; manufactured by Nagase Kasei Co., Ltd.) 1
To 7.5 g, 14.5 g of Neocol SW-30 (dioctyl sulfosuccinate sodium salt; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added as a surfactant, and the mixture is thoroughly stirred and dissolved. Then, while stirring 656.2 g of water at a high speed, the epoxy solution is slowly added and dispersed. The obtained mixture is used as the first treatment agent.

Further, a 10% aqueous solution of sodium hydroxide 6.4g of water 202.2g, 28% ammonia aqueous solution 1
8.8 g is added, the mixture is sufficiently stirred, and 39.5 g of a resorcin-formalin initial condensate (40% acetone solution) obtained by reacting with an acidic catalyst is added, and sufficiently stirred and dispersed. Next, Nippol L was added to 278.0 g of water.
400.7 g of X-1562 (acrylonitrile-butadiene copolymer rubber latex 41% aqueous emulsion; manufactured by Zeon Corporation) is slowly stirred and mixed. The above-mentioned resorcinol-formalin initial condensate dispersion was mixed with the mixed solution while stirring slowly, and further mixed with formalin (37
%) And mix. 30 g of an aqueous dispersion of dimethylpolysiloxane (20% concentration) and 8 g of a 25% aqueous dispersion of a hindered phenolic antioxidant (Irganox 1010, manufactured by Ciba Geigy Corporation) are added. The obtained mixture having a concentration of 20% is used as a second treatment agent.

Aramid fiber (Technola, Teijin Limited)
Made from 1500 denier / 1000 filament
Printer processing machine (Thailand manufactured by CA Ritzler Co., Ltd.)
Immersion in the first treatment agent using a
After drying at 130 ° C for 2 minutes, then at 235 ° C for 1 minute
Heat treatment was performed during the heating. Next, the two processed yarns are combined,
Twist in S direction with twist factor 2 (10.5 turns / 10cm)
Was. This twisted cord 2000m (weight 667g)
And pressurized impregnation of 40 l capacity wound on a bobbin made of stainless steel
Put it in a processing machine (made by Hisaka Seisakusho) container
Tighten and reduce to 10 torr in 15 minutes, then
Put the second treating agent in the container over 20 minutes,
For 20 minutes to impregnate the cord. afterwards,
Reduce the pressure gradually to normal pressure over 5 minutes,
20kg / cm using a sir^TwoAnd hold for 50 minutes
And return to normal pressure. After this, vacuum and pressure impregnation
Remove excess glue from vessel and re-apply 5 kg / cm ^TwoAddition
From the cord wound on the metal bobbin
Removed adhesive. Take out the adhesive impregnated cord and
Drying and heat treatment were performed under the same conditions as for one treatment agent. At this time
Of the adhesive was 20%.

Next, the impregnated twisted yarn cord was changed to RFL (R / R
F = 1 / 2.5 molar ratio, RF / L = 1/5 weight ratio, L =
Treated with acrylonitrile-butadiene copolymer rubber latex; Nipol LX1562 manufactured by Zeon Corporation;
Adjust so that the adhesion rate to the twisted cord is 5%.
It was dried at 30 ° C. for 2 minutes and cured and heat-treated at 240 ° C. for 2 minutes under tension.

The strength of the obtained adhesive treatment cord was measured,
Next, the H-NBR-compounded rubber sheet having a thickness of about 2 mm was arranged in parallel, and the same H-NBR-compounded rubber sheet was overlaid on the cord.
Vulcanization was performed under a pressure of / cm ² to obtain a rubber sheet. This sheet was cut in the length direction of the cords arranged in the rubber using a cutter knife so that the end faces of the cords appeared on the cut surface. Then, the state of the single yarn of the aramid fiber protruding from the end face was visually determined. This end face was rubbed with sandpaper (# AA-150), and the frayed state of the single yarn was observed. Evaluation is (good) ◎ → ○ → △ → × (bad)
Was determined.

Further, the peel adhesive strength,
The pull-out adhesive strength and the strength at fatigue by a belt fatigue tester were measured. Table 1 shows the results.

A cord obtained in the same manner as in Example except that the second treating agent was treated by ordinary normal pressure treatment (no vacuum / pressure impregnation) was used, and the cord obtained in Comparative Example 1 was twisted with the second treating agent. A cord obtained in the same manner as in Example except that the cord was treated before and then twisted was used as Comparative Example 2, and the results are shown in Table 1.

[0041]

[Table 1]

As is clear from the table, after the aramid fiber was treated with the polyepoxide compound, the twisted cord was impregnated with a treating agent containing RFL under vacuum and pressure, and the cord treated with RFL was treated with It can be seen that the strength is high, the fatigue resistance is remarkably improved, and the frayability and adhesiveness are good.

[0043]

Example 2, Comparative Examples 3 and 4 Among the adhesive treatment agents, the polyepoxide treatment agent as the first treatment agent was prepared in the same manner as in Example 1. Further, the RFL of the second treating agent was adjusted according to the adjustment method of Example 1, except that the NBR latex was changed to Nipol 2518FS (vinyl pyridine / styrene / butadiene latex 41% aqueous emulsion; manufactured by Zeon Corporation). After the same treatment as in Example 1, it was treated with RFL containing Nipol 2518FS in the same manner as the second treatment agent.

The cords obtained in the same manner as in the Example except that the second treating agent was subjected to ordinary normal pressure treatment were compared with Comparative Examples 3 and 2
A treated cord obtained in the same manner as in the example except that the treating agent was treated in a fibrous form and twisted was used as a comparative example 4. , Peel adhesion, pull-out adhesion, and fatigue resistance were measured. Table 2 shows the obtained results. As is clear from the table, it can be seen that even when the type of latex is changed, extremely good fatigue, fraying, and adhesive properties are exhibited.

[0045]

[Table 2]

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) D06M 15/00-15/72

Claims (2)

(57) [Claims] An aramid fiber which has been impregnated in advance in a substantially untwisted state with a treatment liquid containing a polyepoxide compound containing two or more epoxy groups and heat-treated at 150 to 260 ° C. for 30 to 210 seconds is 1 ≦ K ≦ 5. (K = (T × D ^1/2 ) / 287
4, K: Twisting coefficient, T: Twisting number expressed in times / m, D: Single yarn fineness) A treatment liquid containing resorcinol-formalin rubber latex (RFL) in twisted aramid fiber cord. After impregnation under vacuum and pressure conditions,
An aramid fiber cord for a power transmission belt, which is heat-treated at 60 ° C. for 30 to 210 seconds, and further treated with a treatment agent containing RFL. 2. The power transmission according to claim 1, wherein the rubber latex in the RFL is acrylonitrile-butadiene (NBR) and / or hydrogenated acrylonitrile-butadiene (H-NBR, a highly saturated copolymer rubber containing a nitrile group). Aramid fiber cord for belt.