JP4205526B2 - Synthetic fiber cord for rubber reinforcement - Google Patents

Description

  The present invention relates to a synthetic fiber cord for rubber reinforcement, and more particularly to a synthetic fiber cord suitable for rubber reinforcement such as for belts and hoses.

  Traditionally, cotton yarn has been used as a fiber cord for rubber reinforcement, but synthetic fibers such as rayon, nylon, and polyester have come to be used with the development of synthetic fibers. Rubber-reinforcing cords made of polyester fibers, which have elastic characteristics, are inexpensive and have excellent dimensional stability, are the mainstream.

  However, the fact that the cord made of polyester fiber does not reach a sufficiently satisfactory level as compared with rayon, nylon, or cotton cord.

  One of the reasons is that polyester does not have an active group like rayon or nylon. Regarding this problem, for example, JP-A-10-46475 discloses RFL (resorcin / formalin / latex) adhesion. JP-A-54-73994 discloses a method for improving adhesiveness by using a one-bath adhesive in which a blocked isocyanate compound and an aromatic polyepoxy compound are added to the agent. A two-bath adhesion treatment method is disclosed in which fibers are treated with a first treatment liquid containing a deisocyanate compound and then treated with an RFL adhesive to improve adhesion.

On the other hand, as another reason that the polyester fiber cord has poor adhesion, it has been pointed out that the cord does not have fluff or loops like cotton cord. 63-12730 discloses a polyester yarn for industrial materials in which a core yarn and a sheath yarn are air entangled and a loop is formed on the surface thereof. The yarn is used for rubber reinforcement. When the cord is to be used as the cord, both the core yarn and the sheath yarn are air entangled, and the high strength and high elasticity characteristics inherent in the polyester fiber may not be sufficiently exhibited. There was a problem.
Japanese Patent Laid-Open No. 10-46475 JP-A-54-73994 JP-A-63-12730

  The object of the present invention is to solve the above-mentioned problems of the prior art, and particularly to improve the adhesiveness to the matrix rubber while fully exhibiting the high strength and high elasticity characteristics inherent in the polyester fiber. Is to provide a synthetic fiber cord.

  As a result of intensive studies to achieve the above object, the inventors of the present invention can obtain a desired synthetic fiber cord when a synthetic fiber continuous filament yarn having fluff or loops provided on its surface is twisted into a cord. As a result, the present invention has been reached.

Thus, according to the present invention, a synthetic yarn continuous filament yarn having no fluff or a loop on its surface and a synthetic fiber continuous filament yarn having a fluff or loop on its surface, the fuzz or loop being The synthetic fiber continuous filament yarn has a false twisted yarn having a tensile strength of 5.0 cN / dtex or more. A synthetic fiber cord for reinforcing rubber is provided.

  According to the present invention, a synthetic fiber cord is provided in which the high strength and high elasticity characteristics inherent in the polyester fiber are sufficiently exhibited, and the adhesion to the matrix rubber is significantly improved. It can be suitably used for rubber reinforcement applications such as for hoses and hoses.

  The synthetic fiber used in the present invention is obtained by spinning and stretching a polymer composed of polyamide represented by nylon 6, nylon 66, polyethylene terephthalate, polyester represented by polybutylene terephthalate, and polyvinyl alcohol by a conventional method. Fiber.

  The above synthetic fibers are desirably drawn using a high-viscosity polymer at a high draw ratio in order to increase the strength.

  In order to obtain the synthetic fiber cord of the present invention, first, among the above synthetic fibers, a continuous filament yarn having no fluff or loop on its surface and a continuous filament yarn having fluff or loop on its surface are combined. It can be obtained by twisting.

  At this time, the total fineness of the continuous filament yarn is preferably 400 to 9000 dtex, and the number of twists during the twisting is preferably 50 to 600 times / m.

  Here, the continuous filament yarn having no fluff or loop on its surface means a continuous filament yarn obtained by spinning, drawing and / or heat treating the above synthetic fiber by a conventional method, and a short fiber such as a staple fiber or a spun yarn. It is a concept that excludes yarns and long fiber yarns provided with loops by air entanglement processing such as Taslan and IL.

  In addition, continuous filaments having fluff or loops on the surface thereof include false twisting, indentation or shaping, such as crimping using the thermoformability of fibers, or air entanglement such as Taslan or IL. This refers to long fiber yarns with fluff or loops. Specifically, two types of synthetic filament continuous filament yarns with different elongations are drawn together, air entangled, and then subjected to false twist crimping. Drawn composite false twisted yarns (manufactured by Teijin Ltd., "Mirpa", "Merkis", etc.) and two types of synthetic filament continuous filament yarns with different elongations are aligned and air entangled before drawing. In this way, a composite stretched yarn (made by Teijin Ltd., “Agenty”, etc.) in which a loop resulting from an elastic recovery difference is formed, or two types of synthetic fiber continuous filament yarns while giving a difference in thread length, And composite air entangled yarn imparted with air interlacing is illustrated.

  In the case of the twisting, the twisting in the lower twisting stage or the twisting in the upper twisting stage may be performed. However, a synthetic fiber continuous filament having fluff or loops on its surface needs to be apparent on the surface of the cord, and the composition ratio is not particularly limited, but is preferably in the range of 5% to 40%.

  The tensile strength of the above-described synthetic fiber continuous filament yarn having fluff or loops needs to be 5.0 cN / dtex or more. When the tensile strength is less than 5.0 cN / dtex, a sufficient reinforcing effect cannot be imparted to the matrix rubber.

  It is preferable that an adhesive is applied to the synthetic fiber cord. Examples of the adhesive to be applied include an adhesive including an epoxy compound, an isocyanate compound, a halogenated phenol compound, and a resorcin polysulfide compound. Specifically, as the first treatment liquid, an epoxy compound, a blocked isocyanate, and a latex are used. A method is preferably exemplified in which after the heat treatment, a liquid (RFL liquid) composed of an initial condensate of resorcin and formaldehyde and a rubber latex (RFL liquid) is applied as the second treatment liquid after the heat treatment.

  For example, in the case of nylon 6 fiber, the drying and heating conditions of the fabric provided with the adhesive are 170 to 215 ° C. for 30 to 90 seconds, preferably 190 to 210 ° C. for 50 to 70 seconds, and in the case of nylon 66 fiber, 200 to 200 ° C. 240 degreeC, 30 to 90 second, Preferably it is 210 to 230 degreeC and 50 to 70 second is good. In the case of polyether, it is treated at 200 to 250 ° C. for 30 to 150 seconds, preferably 210 to 230 ° C. In either case, about 3% stretching is applied.

  Hereinafter, an example is given and the composition and effect of the present invention are explained in detail. In addition, each physical property in an Example is calculated | required by the following method.

(1) Strength of fiber:
Measured according to the method described in JIS L1070 5.1.1.

(2) Peeling adhesion strength This is an index indicating the adhesion strength between the treated cord and rubber. Five cords are buried near the surface of an unvulcanized rubber sheet containing carcass containing natural rubber as a main component. Vulcanize at a press pressure of 500 N / cm ² for 1 minute, and then remove the power required to peel the three cords at a rate of 200 mm / min. This is indicated by / c.

(3) Pull-out adhesive strength This is an index showing the adhesive strength between the treated cord and rubber. The cord is embedded in an unvulcanized rubber block and vulcanized at 150 ° C for 30 minutes at a press pressure of 500 N / cm ^2. Next, the force required to pull out the cord from the rubber block at a speed of 200 mm / min is indicated by N / cm.

Example 1
Using a polyethylene terephthalate straight drawn yarn having a strength of 8.0 cN / dtex, a fineness of 1100 dtex, and a 192 filament obtained according to a conventional method, false twisting was applied to obtain a 1100 dtex false twisted yarn. The tensile strength of the false twisted yarn was 7.0 cN / dtex.

  The false twisted yarn and the polyethylene terephthalate 1100 dtex multifilament were subjected to a lower twist at 300 turns / m in the Z twist direction, and then three were aligned to give an S twist to an upper twist at 200 turns / m.

  The cord is immersed in a first treatment liquid composed of a mixed liquid of an epoxy compound and a blocked isocyanate compound, and then tension-dried for 60 seconds while giving an elongation rate of 2.0% in an oven at 130 ° C. Heat treatment was performed in an oven at 120 ° C. for 120 seconds. Subsequently, the cord was dipped in a second treatment liquid composed of resorcin-formalin-latex (RFL), and then tension-dried for 60 seconds while giving an elongation rate of 0.3% in an oven at 170 ° C., and then 0.6 A 60% heat treatment was performed in an oven at 240 ° C. while giving a% elongation, and a relaxation heat treatment was applied in an oven at 240 ° C. for 60 seconds while giving a relaxation rate of 1.3%.

  When the obtained dip cord was observed, false twisted yarn was found on the cord surface. Table 1 shows the adhesion of the dip cord.

Comparative Example 1
A multifilament of polyethylene terephthalate 1100 dtex was given a lower twist at 300 turns / m in the Z twist direction, and then three of the filaments were drawn together to give an S twist at an upper twist of 200 turns / m. Using this cord, the same adhesion treatment as in Example 1 was performed to obtain a dip cord. The adhesiveness of the dip cord is shown in Table 1.

Comparative Example 2
Using a polyethylene terephthalate semi-drawn yarn having a strength of 5.0 cN / dtex, a fineness of 1100 dtex, and a 192 filament obtained in accordance with a conventional method, a false twisted yarn of 1100 dtex was obtained. The tensile strength of the false twisted yarn was 4.0 cN / dtex.

  The false twisted yarn and the polyethylene terephthalate 1100 dtex multifilament were subjected to a lower twist at 300 turns / m in the Z twist direction, and then three were aligned to give an S twist to an upper twist at 200 turns / m.

  Using this cord, the same adhesion treatment as in Example 1 was performed to obtain a dip cord. The adhesiveness of the dip cord is shown in Table 1.

  According to the present invention, a synthetic fiber cord can be obtained in which the high strength and high elasticity characteristics inherent in the polyester fiber are sufficiently exhibited, and the adhesion to the matrix rubber is significantly improved. If used for rubber reinforcement such as for hoses, the reinforcing effect can be remarkably improved.

Claims (3)

Synthetic fiber continuous filament yarn having no fluff or loop on its surface and synthetic fiber continuous filament yarn having fluff or loop on its surface, the synthetic fiber continuous filament yarn having the fluff or loop is A synthetic fiber cord for reinforcing rubber, which is a false twisted yarn having a tensile strength of 5.0 cN / dtex or more.   The synthetic fiber cord for rubber reinforcement according to claim 1, wherein an adhesive is applied to the cord. The synthetic fiber cord for rubber reinforcement according to claim 1, wherein the number of twists in the twisted yarn is 200 to 600 times / m.