JP5015850B2 - Code, its manufacturing method, and code manufacturing equipment - Google Patents

Description

  The present invention relates to a cord used for reinforcing a rubber article, in particular, a cord with improved fatigue resistance, a method of manufacturing the cord, and a cord manufacturing facility.

  Rubber articles, particularly cords for reinforcing tires, are required to have various characteristics in order to withstand use in harsh environments. In particular, in order to reduce the weight of the tire, it is desired to use a cord having a higher strength by reducing the number of cords used. For this purpose, it is particularly advantageous to improve the fatigue resistance of the cord, and various measures have been taken.

For example, Patent Document 1 and Patent Document 2 propose measures for manufacturing a cord in which an unvulcanized rubber coating layer is provided between a core and a sheath constituting a layered cord. Since the cord is provided with the unvulcanized rubber coating layer, the core filament and the sheath filament come into contact with each other and wear due to rubbing is prevented. In addition, the cord provided with the unvulcanized rubber coating layer has a gap inside the cord filled with rubber, so that when it is used as a tire reinforcement, it can prevent moisture from entering the cord from tire damage. Corrosion due to moisture inside the cord and its propagation are suppressed, and the fatigue resistance of the cord is improved.
JP 2002-266266 A JP 2002-302885 JP

  However, the above-described cord has insufficient improvement in fatigue resistance, and further improvement is required to obtain the intended cord. That is, the above-described cord is manufactured by twisting a sheath filament around a core filament coated with unvulcanized rubber, and at the time of twisting, there is friction between the core filament coated with rubber and the surrounding sheath filament. It will occur. Moreover, the unvulcanized rubber may protrude from the gap between the sheath filaments in the cord after twisting. Therefore, unvulcanized rubber that protrudes from the cord after twisting comes into contact with a guide component such as a metal pulley or guide in the twisting machine that guides the cord, and increases friction between the guide component and the twist cord. become.

  That is, friction between the core filament and the sheath filament coated with the unvulcanized rubber occurs when twisting, and the tension for stabilizing the twist property is disturbed. In addition, when unvulcanized rubber protrudes from between the sheaths, the cords after twisting are not smoothly guided, resulting in variations in the tension applied to the cords. As a result, it becomes difficult to secure the tension necessary to stabilize the twist property. As a result, the alignment of the filaments constituting the cord is deteriorated. For example, the filament of the cord is stretched or swelled, and the cord is not twisted in the same shape in the cord axis direction. When such a cord is used, the filament will break.

  Accordingly, an object of the present invention is to provide a cord having excellent fatigue resistance by eliminating the above-described problems during cord manufacturing.

  As a result of earnestly examining the solution to the above-described problems, the inventors of the present invention manufactured a core filament coated with unvulcanized rubber when manufacturing a cord provided with an unvulcanized rubber coating layer between the core and the sheath. The friction between the twisted sheath filament and the uncured rubber that protrudes between the sheath filaments during cord production and the guide parts in the stranding machine can be reduced by applying an oil treatment to the unvulcanized rubber. The inventor has completed the present invention.

That is, the gist configuration of the present invention is as follows.
(1) A cord in which a sheath made of a plurality of filaments is arranged around a core made of one or a plurality of filaments, and has an unvulcanized rubber coating layer between the core and the sheath, The cord further comprises an oil coating layer on the outer peripheral surface of the unvulcanized rubber coating layer.

  (2) In the cross section orthogonal to the cord axial direction, the cord has an area A of a gap between the core and the sheath, and an area B of an unvulcanized rubber coating layer occupied between the core and the sheath, A ≦ B ≦ The cord according to (1) above, wherein the relationship 4A is satisfied, and the amount X of oil adhesion in the oil coating layer satisfies 50 (mg / kg) ≦ X <1400 (mg / kg).

  (3) In the cross section orthogonal to the cord axial direction, the cord has an area A of the gap between the core and the sheath and an area B of the unvulcanized rubber coating layer occupied between the core and the sheath of 4A <B ≦ 10. The cord according to (1), wherein the cord satisfies the relationship of 10A and the amount Y of oil in the oil coating layer satisfies 80 (mg / kg) ≦ Y <1400 (mg / kg).

  (4) When manufacturing a cord by twisting a plurality of filaments serving as a sheath around a core composed of one or more filaments, the one or more filaments serving as the core are made into unvulcanized rubber. A method for producing a cord, further comprising applying oil to an outer peripheral surface of the unvulcanized rubber coating layer, and then twisting together a plurality of filaments serving as a sheath.

  (5) A core unwinding section for unwinding one or more core filaments to be the core, a sheath unwinding section for unwinding multiple sheath filaments to be the sheath, and the core filament and the sheath filament are converged and twisted together An apparatus for manufacturing a cord in which a stranding machine is arranged in order, and an unvulcanized rubber coating device for coating the core filament with unvulcanized rubber is installed on the exit side of the core unwinding portion, A cord manufacturing facility, wherein an oil application device for applying oil to unvulcanized rubber is installed on the exit side of the vulcanized rubber coating device.

  In the cord of the present invention, a core composed of one or a plurality of filaments is coated with unvulcanized rubber, and further, oil is applied to the outer peripheral surface of the unvulcanized rubber coating layer, and then a plurality of sheaths serving as a sheath It is obtained by twisting the filaments. That is, the friction between the core filament and the sheath filament during twisting in the cord manufacturing process and the friction between the guide parts in the twisting machine and the unvulcanized rubber protruding between the sheath filaments in the cord after twisting are caused by the oil coating layer. In order to reduce, sound twisting under the intended tension is realized. As a result, the filaments are well aligned during twisting, and a cord having excellent fatigue resistance can be provided.

  Next, the cord of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a cross section perpendicular to the axial direction of the cord according to the present invention. FIG. 1 shows a cord 3 in which a filament of the same diameter formed by twisting nine sheath filaments 2a serving as a sheath 2 is twisted around a core 1 composed of three core filaments 1a. The cord 3 has an unvulcanized rubber coating layer 4 between the core 1 and the sheath 2 as shown by vertical lines in FIG. It is characterized in that an oil coating layer 5 is provided on the surface. In addition to the cord shown in FIG. 1, it is also possible to make a compact twist in which the core and the sheath filament shown in FIG. 2, for example, are twisted in the same direction and at the same pitch.

  That is, the cord 6 shown in FIG. 2 is obtained by twisting nine sheath filaments 8a serving as a sheath 8 around the core 7 composed of three core filaments 7a in the same direction and at the same pitch. The diameters of the filament 7a and the sheath filament 8a are different. Also in this cord 6, it is important to provide the unvulcanized rubber coating layer 4 and the oil coating layer 5 in the same manner as described above in the same manner as the cord 3 described above. Furthermore, the same effect as shown below can also be obtained by twisting a plurality of strands as each strand constituting the cord having a double twist structure.

  Now, in the cord according to the present invention, by providing the oil coating layer 5 on the outer peripheral surface of the unvulcanized rubber coating layer 4, a sound twist property can be realized in the following cord manufacturing process. Therefore, the cord having the excellent fatigue resistance inherent to this type of cord can be obtained. Hereinafter, the manufacturing method of the present invention will be described in detail with reference to the cord manufacturing facility shown in FIG.

  That is, the cord manufacturing facility shown in FIG. 3 has a predetermined number of core unwinding portions 9 for unwinding the core filament 9a and sheath unwinding portions 10 for unwinding the sheath filament 10a, and unwinds from each unwinding portion. A wire concentrator 11 for converging the filaments and a stranded wire machine 12 for twisting the converging filaments are provided. Then, between the core unwinding portion 9 and the wire concentrator 11, oil is applied to the outer peripheral surface of the unvulcanized rubber coating device 13 and the unvulcanized rubber coating layer 4 for coating the core filament 9a with the unvulcanized rubber. An oil applicator 14 is installed. Here, the oil coating device 14 is installed on the exit side of the unvulcanized rubber coating device 13 in order to provide the oil coating layer 5 on the outer peripheral surface of the unvulcanized rubber coating layer 4.

  Next, in the method of manufacturing a cord with the above-described cord manufacturing facility, first, the core filament 9a wound around the core unwinding portion 9 is unwound and led to the unvulcanized rubber coating device 13 side, and the unvulcanized rubber The coating apparatus 13 coats the core filament 9a with unvulcanized rubber to obtain an unvulcanized rubber-coated filament 13a. Next, the unvulcanized rubber-coated filament 13a is supplied to the oil coating device 14 disposed on the exit side of the unvulcanized rubber coating device 13, and the oil coating device 14 applies the outer surface of the unvulcanized rubber coating layer 4 to the outer surface. Oil is applied to form an oil-coated filament 14a. Further, the oil application filament 14a is supplied to the wire concentrator 11 installed on the entry side of the stranding machine 12, and the wire concentrator 11 unwinds from the sheath unwinding portion 10 around the oil application filament 14a. The sheath filament 10a is converged to form a converging filament 11a, and the converging filament 11a is supplied to the stranding machine 12. Then, the cord 15 is obtained by twisting the converging filaments 11a by the twisting machine 12.

  Here, the core filament 9a unwound from the core unwinding portion 9 is coated with unvulcanized rubber, and further, oil is applied to the outer peripheral surface of the unvulcanized rubber coating layer 4, and then supplied to the stranded wire machine 12. It is important. In other words, the fact that oil is applied to the outer peripheral surface of the unvulcanized rubber coating layer 4 means that the oil is also attached to the unvulcanized rubber protruding from between the sheath filaments constituting the twisted cord. Become.

  Therefore, it is possible to reduce friction when the unvulcanized rubber protruding from between the sheath filaments and the guide parts in the stranding machine 12 come into contact with each other. Therefore, the tension necessary for obtaining a sound twist property can be obtained uniformly, and as a result of good alignment during twisting of the cord, a cord having excellent fatigue resistance can be manufactured.

  Further, the unvulcanized rubber and the sheath filament 10a, which are generated when the oil-coated filament 14a and the sheath filament 10a are twisted by forming the oil-coated filament 14a with the oil applied to the outer peripheral surface of the unvulcanized rubber coating layer 4, Friction can be reduced. That is, the tension applied to the sheath filament 10a is also obtained uniformly by reducing the friction, resulting in a balanced cord with improved twisting properties of the cord.When this cord was used for tire reinforcement, Even when a relatively large load is applied to the tire, high fatigue resistance can be ensured.

  The unvulcanized rubber coating apparatus 13 for coating the core filament 9a with unvulcanized rubber includes, for example, a rubber extruder 16 and a rubber extrusion head unit 18, as shown in FIG. Here, in FIG. 4, as shown inside the rubber extruder 16 and the rubber extrusion head portion 18, in the unvulcanized rubber coating apparatus 13, the rubber extrusion head portion is passed through the rubber extrusion screw 17 from the rubber extruder 16 side. Unvulcanized rubber 19 is extruded into 18 to fill the rubber extrusion head portion 18 with unvulcanized rubber. Next, when the core filament 9a is supplied into the rubber extrusion head portion 18 from the cord guide 20 installed on the entrance side of the rubber extrusion head portion 18, and passed through the rubber extrusion head portion 18, the peripheral surface of the core filament 9a Is coated with unvulcanized rubber 19. Thereafter, the core filament 9a coated with the unvulcanized rubber 19 is guided to the outside of the rubber extrusion head unit 18 while adjusting the thickness of the coated rubber through a base 21 installed on the exit side of the rubber extrusion head unit 18. Thus, the unvulcanized rubber-coated filament 13a is obtained. In the present invention, when the uncured rubber is coated on the core filament 9a with the unvulcanized rubber coating apparatus 13, a plurality of core filaments 9a are coated at the same time. It is also possible to coat.

  Further, the unvulcanized rubber-coated filament 13a, as shown in FIG. 5, shows the inside of the oil coating device 14, supplying the oil 23 sucked up by the string 22 to the groove of the pulley 24, and the pulley 24 is unvulcanized. Oil is applied to the outer peripheral surface of the unvulcanized rubber-coated filament 13a by passing the rubber-coated filament 13a and allowing the unvulcanized rubber-coated filament 13a to be submerged in the oil in the groove. In the present invention, when the oil is applied to the outer peripheral surface of the unvulcanized rubber coating layer 4 by the oil coating device 14, a plurality of unvulcanized rubber coated filaments 13a are simultaneously applied. Similarly to the vulcanized rubber coating apparatus 13, uncured rubber coated filaments 13a can be applied one by one.

  Here, the oil applied to the unvulcanized rubber coating layer 4 of the unvulcanized rubber-coated filament 13a is not particularly limited, but it is preferable to use an oil for a rubber softening material. In other words, the oil for rubber softener does not impair the adhesion to rubber, and guides the unvulcanized rubber protruding from between the sheath filaments after twisting in the cord production process in the cord manufacturing process. Reduction of friction with parts and friction generated when twisting the unvulcanized rubber-coated filament 13a and the sheath filament 10a can be realized.

  Furthermore, in the cord of the present invention, in the cross section orthogonal to the axial direction of the cord, the area A of the gap between the core and the sheath and the area B of the unvulcanized rubber coating layer occupied between the core and the sheath are set as A ≦ B ≦ 4A. In addition, it is preferable that the amount X of oil adhesion in the oil coating layer is 50 (mg / kg) ≦ X <1400 (mg / kg). Further, the area A of the gap between the core and the sheath and the area B of the unvulcanized rubber coating layer occupying between the core and the sheath are 4A <B ≦ 10A, and the oil adhesion amount Y in the oil coating layer is 80 (mg / kg) ≦ Y <1400 (mg / kg).

  Here, the area A of the gap between the core and the sheath is defined with reference to the closed cord. For example, as shown in FIG. 6A for a closed cord having the same structure as that shown in FIG. 1 and as shown in FIG. 6B for a closed cord having the same structure as that shown in FIG. Let the gap between the core and the sheath in A be the area A {dotted line portion in FIGS. 6A and 6B}. However, as shown in FIG. 6B, the gap between the sheaths 28 where the core 27 is not interposed is excluded.

  The area B of the unvulcanized rubber coating layer 4 occupying between the core 27 and the sheath 28 is a rubber portion (vertical line portion) coated around the core as shown in FIGS. 1 and 2.

  Here, in producing the cord shown in FIG. 1 or FIG. 2, in order to form the rubber coating layer 4 that is 1 to 4 times or less than 10 times the area A, as shown in FIG. After coating the unvulcanized rubber corresponding to B around the core filament, the sheath filament may be twisted together.

  That is, if the area B of the unvulcanized rubber coating layer between the core and the sheath is less than the area A of the gap between the core and the sheath determined first, the rubber penet is insufficient and the fatigue resistance is improved. unacceptable.

  Also, if the area B of the unvulcanized rubber coating layer that occupies between the core and the sheath exceeds the area 10A of the gap between the core and the sheath, excess rubber that cannot fit inside the cord causes twisting of the cord. As a result, fatigue resistance is deteriorated.

  Next, the oil adhesion amount Y (mg / kg) in the oil coating layer is defined as the weight of oil deposited per 1 kg of the cord.

  The area A of the gap between the core and the sheath and the area B of the unvulcanized rubber coating layer occupied between the core and the sheath are A ≦ B ≦ 4A, and the amount of oil adhesion X in the oil coating layer is 50 (mg / mg kg), or the area A of the gap between the core and the sheath and the area B of the unvulcanized rubber coating layer occupied between the core and the sheath satisfy 4A <B ≦ 10A, and the amount of oil adhering to the oil coating layer If Y is less than 80 (mg / kg), an oil coating layer necessary to reduce friction generated between the unvulcanized rubber protruding from between the sheath filaments and the guide parts in the stranding machine may be formed. It becomes difficult. When the oil adhesion amounts X and Y are 1400 (mg / kg) or more, the oil is scattered in the cord manufacturing process, the cord manufacturing equipment is contaminated, and the environment of the stranded wire process is deteriorated.

  Further, the area B of the unvulcanized rubber coating layer between the core and the sheath is A ≦ B ≦ 6A, and the amount of oil adhesion X and Y in the oil coating layer is 80 ≦ X ≦ 500 or 80 ≦ Y ≦ 500 is preferable. This is because if the amount of rubber is too large, the cost increases, and therefore, A ≦ B ≦ 6A is suitable as the coating amount that can ensure stable rubber penet quality. The amount of oil attached is preferably controlled to 80 ≦ X ≦ 500 or 80 ≦ Y ≦ 500 in view of uniform adhesion in the longitudinal direction of the cord.

  As described above, by manufacturing the cord according to the present invention using the above-described manufacturing method and cord manufacturing equipment, the cord is made up of unvulcanized rubber protruding from the sheath filament and guide parts in the stranding machine. It is possible to go through a smooth manufacturing process with reduced friction. As a result, this cord does not have a variation in tension necessary to obtain a sound twist property, and the cord can be satisfactorily aligned, thereby providing a cord having excellent fatigue resistance.

Using the above-described cord manufacturing method using the cord manufacturing facility shown in FIG. 3, the cord of the 3 + 9 × 0.22 structure shown in FIG. 1 and the filament of 3 × 0.24 + 9 × 0.22 shown in FIG. Cords twisted in the same direction and at the same pitch were produced according to the specifications in Table 1 and Table 2, respectively. And about these cords, the fatigue resistance index, the cord cracking judgment, and the oil scattering judgment were investigated. The results are shown in Tables 1 and 2. Table 1 shows the results of cords in which filaments of the same diameter shown in FIG. 1 are twisted together, and Table 2 shows the results of cords in which filaments of different diameters shown in FIG. 2 are twisted in the same direction and at the same pitch. .

  Here, the fatigue resistance index was evaluated by the following means. First, a vulcanized rubber sheet was prepared by vulcanizing a rubber sheet in which a plurality of cords were arranged and embedded so that the cords were parallel to each other at equal intervals under pressure and heating. Next, the vulcanized rubber sheet is subjected to the compression / bending fatigue strength test A method (Firestone method) according to JISL 1017 with a roller with a radius of curvature of 15 mm, and the number of times the vulcanized rubber sheet is bent until it breaks. Was measured. And using this measured value, the fatigue resistance of each cord was indexed and evaluated. As for the index value of each cord, the cord in which filaments having the same diameter shown in FIG. 1 are twisted is the same as that in Conventional Example 1, and filaments having different diameters shown in FIG. 2 are twisted in the same direction and at the same pitch. The code is assumed to be indexed with the conventional example 2 as 100. Moreover, it shows that fatigue resistance is so high that the value of a numerical value is high.

  Regarding the code breakage determination, in order to determine the deterioration of the alignment due to the slip failure in the cord production, the cracking property due to the cord bending and ironing was evaluated in two stages. As shown in Fig. 6, the cord is bent and ironed to make a loop with a diameter of 15 cm using a cord 15 with a length of about 2 m, and while holding the intersection 25 with the left hand, the loop diameter is about 1.0 cm. After pulling the right end of the loop until it is, the cord 15 is bent and ironed, the cord 15 is released, and the cracked state of the top 26 of the loop is determined. The state in which the filament in the cord does not stretch or bulge is marked as ◎ (mal), and the part of the filament in the cord that is slightly stretched or bulged is marked as ◯ (mal), and the filament in the cord △ (sangaku) was evaluated for the state of stretching or swelling.

  Furthermore, for oil splash determination, we evaluated the contamination and deterioration of workability due to oil splash in the stranding machine in the cord manufacturing process in three stages. In addition, about this evaluation, ◎ (Nijimaru) is the same situation as normal work, ○ (Maru) is a situation where parts of the stranded wire machine become dirty due to splashing of oil, and periodic cleaning is necessary. Sangaku (△) is a level where oil scattering is severely disturbing the adjustment of parts in the stranding machine.

FIG. 3 is a diagram showing a cord in which filaments of the same diameter with a 3 + 9 structure are twisted together. FIG. 3 is a view showing a cord in which filaments having different diameters of 3 + 9 structure are twisted in the same direction and at the same pitch. It is the figure shown about the cord manufacturing equipment used in order to manufacture the code | cord | chord of this invention. It is the figure which showed a mode that a core filament was coat | covered with unvulcanized rubber using an unvulcanized rubber coating apparatus. It is the figure which showed a mode that oil was apply | coated to the outer peripheral surface of an unvulcanized rubber filament. FIG. 3 is a diagram showing an area A of a gap between a core and a sheath and an area B of an unvulcanized rubber coating layer occupied between the core and the sheath. It is the figure which showed the investigation method of code | cord | chord cracking determination.

Explanation of symbols

1 Core 1a Core filament 2 Sheath 2a Sheath filament 3 Cord 4 Unvulcanized rubber coating layer 5 Oiled layer 6 Cord 7 Core 7a Core filament 8 Sheath 8a Sheath filament 9 Core unwinding section 9a Core filament 10 Sheath unwinding section 10a Sheath filament 11 Wire concentrator 11a Converging filament 12 Stranding machine 13 Unvulcanized rubber coating device 13a Unvulcanized rubber coating filament 14 Oil coating device 14a Oil coating filament 15 Code 16 Rubber extruder 17 Rubber extrusion screw 18 Rubber extrusion head 19 Not yet Vulcanized rubber 20 Code guide 21 Base 22 String 23 Oil 24 Pulley 25 Intersection 26 Loop top 27 Core 28 Sheath

Claims (5)

  A cord in which a sheath made of a plurality of filaments is arranged around a core made of one or a plurality of filaments, and has an unvulcanized rubber coating layer between the core and the sheath, A cord comprising an oil coating layer on an outer peripheral surface of an unvulcanized rubber coating layer.   In the cross section orthogonal to the cord axis direction, the cord has a relationship in which the area A of the gap between the core and the sheath and the area B of the unvulcanized rubber coating layer occupied between the core and the sheath are A ≦ B ≦ 4A 2. The cord according to claim 1, wherein an amount X of oil adhesion in the oil coating layer satisfies 50 (mg / kg) ≦ X <1400 (mg / kg).   In the cord, in the cross section orthogonal to the cord axis direction, the area A of the gap between the core and the sheath, and the area B of the unvulcanized rubber coating layer occupied between the core and the sheath are in a relationship of 4A <B ≦ 10A 2. The cord according to claim 1, wherein the amount of oil adhesion Y in the oil coating layer satisfies 80 (mg / kg) ≦ Y <1400 (mg / kg).   When manufacturing a cord by twisting a plurality of filaments serving as a sheath around a core composed of one or more filaments, the one or more filaments serving as the core are coated with unvulcanized rubber. Furthermore, a method for producing a cord, wherein oil is applied to the outer peripheral surface of the unvulcanized rubber coating layer, and then a plurality of filaments serving as a sheath are twisted together.   A core unwinding section for unwinding one or a plurality of core filaments as a core, a sheath unwinding section for unwinding a plurality of sheath filaments as a sheath, and a strand wire machine for converging and twisting the core filament and the sheath filament Are installed in order, and an unvulcanized rubber coating device for coating the core filament with unvulcanized rubber is installed on the exit side of the core unwinding section, and the unvulcanized rubber coating is further provided. A cord manufacturing facility characterized in that an oil application device for applying oil to unvulcanized rubber is installed on the outlet side of the device.

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