JP4266156B2 - Tire cord and pneumatic tire - Google Patents

Description

  The present invention relates to a tire cord in which the strength and cord diameter of a joint portion obtained by joining two cord end portions are maintained at the same level as a body portion cord, and a pneumatic tire reinforced with the tire cord.

  As a reinforcing material for the carcass layer and belt reinforcement layer of pneumatic tires, a single tire cord is used so that no joint is formed between the reinforcing members in the tire circumferential direction (jointless tire), and no weft is used. It has been proposed to improve the weight and uniformity of tires by using rubber coated with a rubber cord as a reinforcing material, and the single cords used for these need to be extremely long and adhere to rubber In order to ensure dimensional stability, the cord needs to be subjected to adhesive treatment or heat treatment.

  In order to obtain such a long tire cord, a long cord is joined by a knot method that mechanically connects two cord ends or an air joint method that twists using a swirling air flow. It is generally performed (Patent Document 1), and a joining method is disclosed in which the ends of the yarn are thermally melted and the melted ends are fused together (Patent Document 2).

  In addition, a single tire cord that has been treated with adhesive treatment or the like is extremely inefficient in the method of processing the cords one by one, and a large number of cords are simultaneously processed using a special device such as a cord setter. In this method, since the cords are not connected to each other by wefts, the cords are easy to move and troubles occur, and an expensive device for equalizing the tension of the cords is required. Low and high cost.

Therefore, at each end of the longitudinal direction of the interwoven fabric using the tire cord as a warp, the end of the warp is alternately connected to the end of the adjacent warp on one side thereof, and the interwoven fabric is formed of a plurality of arbitrary warps. After the adhesive treatment, a cord reinforcement fabric for reinforcing tires has been proposed in which a long treated tire cord can be obtained by taking out the warp (Patent Document 3).
Japanese Patent Laid-Open No. 2002-362836 JP 2000-239935 A Japanese Patent Laid-Open No. 11-245614

  By the way, in order to fabricate a reinforcing material coated with a single tire cord and covered with rubber, for example, an extruder or a calendar device is arranged by arranging a large number of cords by means such as passing them through comb-shaped scissors or harmonica-shaped guide holes. By supplying to the rubber and topping the rubber, a long topping sheet made only of warp can be obtained, and can be suitably used as a tire reinforcing material.

  However, the long tire cord has joints by knot method or air joint method in some places, and even in the joining method described in Patent Document 2, the fusion part becomes a protruding portion having a large diameter. When supplied to the topping process, the knot or filament of the joint protruding from the cord may be caught in the ridge or the guide hole, or the cord may break due to insufficient joint strength.

  Once troubles such as cord breakage occur, there is a problem that requires a laborious and time-consuming operation of disassembling the extruder die, aligning the cords, and passing them through the scissors and guide holes.

  In addition, when using the above topping sheet as a tire reinforcement, it is necessary to remove the joint part from the lack of strength of the joint part by the knot method or air joint method or the protruding part may adversely affect the tire performance. There is also an increase in man-hours and material loss.

  The present invention is a processed single tire cord used as a reinforcing material for a pneumatic tire, and is a long tire capable of maintaining the strength and cord diameter of the joint portion as the main body cord by a simple joining method. A cheaper long tire cord obtained by efficiently taking out a warp as a cord from a cord fabric or a warp fabric that has been processed by joining warps at the ends of the fabric, and tire performance reinforced with the tire cord It aims at providing the pneumatic tire which secured.

  The tire cord of the present invention is a tire cord in which two cords made of thermoplastic synthetic fibers are connected via a joint portion, and the joint portion thermally melts two cord terminal portions, and the heat cord The melted terminal portions are fused to each other, and then the fused portion in a semi-solidified state is stretched and formed.

  According to the tire cord of the present invention, since the joint portion is formed by stretching and solidifying the fused portion of both cord ends, this joint portion has the strength of the fiber material itself that forms the cord and ensures a cross-sectional area. This makes it possible to obtain a long tire cord that maintains the strength and cord diameter of the joint at the same level as the main body cord, and prevents troubles such as wrinkles and cord breakage caught in the guide hole during rubber topping. Operation can be performed, troublesome work at the time of trouble can be released and processing efficiency can be improved, and even if the joint portion is included in the tire as it is, tire performance is not deteriorated. Further, an infinite length tire cord can be obtained by eliminating the need for a joining medium such as an adhesive for cord joining and further repeating joining at the end of the cord.

  Further, the tire cord of the present invention is the end of the warp where the end of the warp is adjacent to one side at both ends in the longitudinal direction of a long weave fabric obtained by weaving a warp made of a thermoplastic synthetic fiber tire cord together with a weft. Tire cord obtained by taking out the warp from an interwoven fabric in which a plurality of warps are continuously joined to each other, wherein the joint of the end portions of the interwoven fabric has two warp ends It is characterized in that it is formed by thermally melting parts and fusing the heat-melted terminal parts together, and then stretching the fused part in a semi-solidified state.

  According to the tire cord of the present invention, since any warp adjacent to one side at the end of the interwoven fabric longitudinal direction is joined and continuous, the warp of the interwoven fabric is subjected to a treatment such as an adhesive treatment. By taking out the tires in order from the side end, the tire cords of the length of the cords are at least twice as long as the length of the weave fabric, which maintains the strength and cord diameter of the joint portion at the same level as the warp yarn of the body portion. It can be obtained efficiently and the manufacturing cost of the single cord can be reduced.

  In the above weave fabric, the end of each warp is joined to the end of one of the adjacent warps at one end in the fabric longitudinal direction, and at the other end in the fabric longitudinal direction. The warp yarns may be joined to the end portions of the warp yarns on the opposite side to the warp yarns on both sides, and the respective warp yarns may be alternately continued at both end portions.

  As a result, the warp yarns are alternately joined at both ends in the longitudinal direction of the fabric and are continuously connected to each other. An extremely long cord with a single warp can be obtained.

  Further, in the interwoven fabric, any odd-numbered warp counted from the side end and the even-numbered warp adjacent thereto are not joined at the end, and the non-joined end of the warp is at least one of the longitudinal direction of the fabric A plurality of long tire cords having a length more than several times the length of the interwoven fabric can be obtained.

  When these interwoven fabrics are wound in a roll shape so that the non-joined end portion of the warp is on the surface side of the wound body, the warp yarn is pulled out while pulling out the interwoven fabric from the roll-shaped wound body. The warp yarn can be pulled out from one end side in the fabric axial direction from the roll-shaped wound body so that the warp yarns joined at the fabric end portion can be pulled out successively in the axial direction. Thus, the work for taking out the warp can be performed efficiently.

  Further, these braided fabrics may be wound in a roll shape, and the non-joined end portions of the warps may be mixed on the surface side and the core side of the wound body. Also in this case, the operation of taking out the warp from the interwoven fabric can be performed efficiently as described above.

  In the tire cord of the present invention, it is preferable that the outer diameter of the joint portion is 0.8 to 1.1 times the main body cord diameter. It is possible to reliably prevent troubles such as cord breakage caused by catching, enabling continuous operation, and greatly improving topping efficiency.

  In the tire cord of the present invention, it is preferable that the cross-sectional shape of the joint portion is formed in a substantially circular shape, so that the processability of the cord in the topping step and the like can be further improved and the strength of the joint portion can be stabilized.

  In the tire cord of the present invention, when the cord strength at the joint portion is 60% or more of the cord strength of the main body portion, the cord breakage due to the tension at the time of topping can be prevented, and high-speed topping processing can be performed. Even if the joint portion is included, the tire reinforcing performance is not deteriorated and the tire basic performance such as durability can be secured.

  And since the pneumatic tire of the present invention reinforced with the above tire cord maintains the strength and cord diameter of the cord joint portion, even if this joint portion is included in the tire, the tire strength is reduced or the joint portion As a result, it is possible to ensure durability, uniformity and the like without causing any foreign matters and material loss, and to contribute to weight reduction of the tire by reducing the thickness of the seat.

  According to the tire cord of the present invention, it is possible to obtain a long tire cord that maintains the strength and cord diameter of the joint portion in the same manner as the body portion cord, and further, by repeating joining of the cord end portion, an infinite length tire cord is obtained. It can also be obtained.

  In addition, by forming a joint between warp yarns at the end of the interwoven fabric using the tire cord as the warp, and sequentially taking out the warp from the side end, a tire cord that is at least twice as long as the interwoven fabric can be obtained efficiently. Therefore, the manufacturing cost of the single tire cord can be greatly reduced.

  In addition, this cord prevents troubles such as cord breakage at the time of topping, frees you from troublesome recovery work at the time of trouble, enables continuous operation, and remarkably improves the production efficiency of topping sheets without weft.

  In addition, the pneumatic tire of the present invention maintains the strength of the cord joint and the cord diameter. Therefore, even if the joint is included in the tire as it is, the tire strength is not reduced, and durability and uniformity are not reduced. This ensures tire performance such as Mitty and contributes to weight reduction.

  Hereinafter, the present invention will be described based on embodiments.

[First Embodiment]
FIG. 1 shows a tire cord according to the first embodiment of the present invention, and FIG. 2 schematically shows an example of a cord joining method.

  A tire cord 1 of the present invention is a tire reinforcing cord having a fineness of 500 to 5000 dtex made of a filament made of a thermoplastic synthetic fiber such as polyester or nylon, and has a predetermined number of twists as shown in the figure. A multifilament yarn that has been applied is generally used, and is a treated cord that has been subjected to adhesion treatment (RFL treatment or the like) with rubber and heat treatment. The cord 1 may be one relatively thick monofilament yarn.

  The tire cord 1 is a long tire cord in which two cords 11 and 12 are connected via a joint portion 13, and the joint portion 13 is obtained by fusing two cord ends that are thermally melted together. The fused portion in a semi-solid state is stretched and re-solidified.

  As shown in FIG. 2, the end portions 11a and 12a of both the cords 11 and 12 are first melted by the heating means 14 (FIG. 2A), and the tire cord 1 is joined with a thermoplastic synthetic material. After forming the fiber melted portions 11b and 12b ((b)), aligning the axial cores of the melted portions 11b and 12b, and butt-welding them to form one mass fused portion 13a ((c )), The fused portion 13a in a semi-solid state is stretched by applying a tensile force F in the cord axis direction, and re-solidified so that the cord shaft core is straight, and the cord diameter D1 of the joint portion 13 is the main body. The joining portion 13 is formed (FIG. 1) so as to be 0.8 to 1.1 times the part code diameter D0 and joined.

  The cross-sectional shape of the joint 13 is preferably formed in a substantially circular shape, and a semi-solid fusion formed in advance in a substantially circular cross-section by a method such as sliding the semi-solid fusion part 13a with a finger. The portion 13b is stretched with a tensile force F ′ (FIG. 2 (d)), or the semi-solid fusion portion 13b is deformed while sliding the semi-solid fusion portion 13a with a finger in a substantially circular cross section. A substantially circular cross section is obtained by stretching.

  As the heating means 14 for thermally melting the cord terminal portions 11a and 12a, a method of roasting and melting the cord terminal portion using an open flame such as a gas burner or a lighter, the cord terminal portion is brought into contact with a hot plate such as an electric heater. Examples include a method of melting, a method in which ultrasonic vibration is applied to the cord end portion, and the fiber itself generates heat by its vibration friction to melt, but the thermoplastic synthetic fiber constituting the cord is in a molten state without burning. If so, the means is not particularly limited, and other bonding media such as an adhesive are not required for the cord bonding, so that the number of work steps is not required and the bonding cost can be suppressed.

  It is conceivable to use a fusing device equipped with a cord abutting mechanism in order to make the lump fusion portions 11b and 12b of the cord terminal abut and fuse to form a lump fusion portion 13a. It is simple and good to work by aligning the shaft cores of the code terminals and performing butt fusion.

  Further, as shown in FIG. 3, the end portions 11a and 12a of both cords 11 and 12 are preliminarily overlapped to form a joined portion, and the joined portion is thermally melted by the heating means 14 (FIG. 3 (a)). One lump-like fusion part 13a (same (b)) may be used.

  The method of stretching the semi-solidified fused portion 13a obtained in this way is not particularly limited, but requires a short time to complete stretching before solidification of the fused portion 13a. A method of easily solidifying while confirming the solidification state such as the outer diameter and the cross-sectional shape of the joint portion 13 by visually grasping both sides of the landing portion 13a by hand and applying a tensile tension F in the cord axis direction.

  As described above, the joining work from the melting of the cord end to the solidification is completed in a short time, so it can be handled easily and quickly by hand, but of course, a series of processes from melting to solidification. It can also be carried out using a joining apparatus that performs the work, for example, comprising two cord supply means, a melting means and a fusion means for the cord terminal, a stretching means, and the like, and performs a series of work continuously.

  The cord diameter D1 at the joint 13 of the tire cord 1 obtained as described above is 0.8 to 1.1 times, preferably 0.9 to 1.05 times the body portion cord diameter D0, and Is preferably 0.9 to 1.03 times.

  If the joint cord diameter D1 is less than 0.8 times D0, the cross-sectional area of the joint portion 13 is insufficient and sufficient joint strength cannot be ensured, resulting in the occurrence of cord breakage due to tension during topping and the reinforcement of the tire. Let When D1 exceeds 1.1 times, when the cord 1 passes through the crease or the guide hole, the probability that the joint portion 13 is caught by the crease or the hole increases rapidly, and troubles such as cord breakage occur frequently.

  As a result, the cord diameter D1 of the cord joint 13 is maintained at the same level as that of the main body cord, and knot-like knots and filament whiskers of the conventional joining method are eliminated, and the joint 13 of the tire cord 1 is combed during topping. The cord can be caught or clogged in the shape of a hook or harmonica guide hole, and the guide hole can be prevented from clogging, and derailment from the roll groove of the calendar can be prevented. Free up work and improve machining efficiency. In addition, the appearance of the topping sheet can be improved without causing the joint portion 13 to bulge or dent on the sheet surface, and the tire performance such as uniformity can be improved.

  These tire cords 1 are preferably formed so that the cross-sectional shape of the joint portion 13 is formed in a substantially circular shape, the joint portion 13 is not caught in the ridge or the guide hole in the topping process, and the breakage of the cord is more reliably prevented. The handling property is improved and the processability of the cord can be further improved. Further, since the fused portion 13a is uniformly stretched to form the joint portion 13 having a substantially circular cross section, the cross-sectional shape of the joint portion 13 is stabilized. Thus, the bonding strength can be improved.

  In order to form the joint portion 13 in a substantially circular cross-sectional shape, the fused portion 13a in a semi-solid state is slid by fingers with rubber gloves or the like, or the fused portion 13a is sandwiched between two plate-like bodies. The semi-solid fused portion 13a is previously made to have a substantially circular cross-sectional shape by a method such as rolling, or the semi-solid fused portion 13a is stretched while being deformed into a substantially circular cross-sectional shape. It can be easily implemented.

  The cord strength at the joint 13 is 60% or more of the main body cord strength, and more preferably 70% or more. As a result, it is possible to prevent the occurrence of cord breakage due to both tensions applied from opposite directions of the winding side and the drawing side at the time of topping processing, enabling topping processing at a high speed similar to that of the non-joined cord, and the joining portion 13 in the tire. In particular, durability can be ensured without deteriorating the reinforcing property even if it is included as it is in a reinforcing layer that becomes a tire skeleton such as a carcass layer.

  In addition, the length L of the joining portion 13 is not particularly limited, but may be about 2 to 20 mm as long as the joining strength is ensured. If the length L is too short, it will be difficult to fuse and stretch the cord terminals, and the strength of the joint 13 will be insufficient, and if it is too long, it will be difficult to perform heat melting, fusion and stretching, and the linearity of the cord will be reduced. In addition to causing breakage of the cord at the time of topping and the like, the rigidity of the joint 13 is increased and the handleability of the cord is lowered, and the tire performance is also adversely affected.

  The tire cord 1 obtained in this way becomes a long tire cord whose joint 13 has the same strength and cord diameter as the main body cord, and is further lengthened by repeating the joining of the cord end, An infinite length tire cord can also be used, and a reinforcing material suitable for use in a pneumatic tire can be obtained without causing troubles such as cord breakage in the rubber topping process.

  The tire cord 1 may be a single tire cord that has been processed by adhesive treatment and heat treatment after two untreated cords are joined and lengthened at the end thereof.

[Second Embodiment]
The second embodiment is a long tire cord that can be efficiently obtained by taking out, as a tire cord, a warp in which adjacent warp ends are joined from a treated comb fabric.

  FIG. 4 shows an example of the interwoven fabric 2 according to the second embodiment, and FIG. 5 is an enlarged view of a part thereof. As shown in the figure, the weave fabric 2 has a tire cord made of a thermoplastic synthetic fiber such as polyester or nylon as a warp, hundreds to thousands of warps 20 and the longitudinal direction of these warps 20 are required. It is woven into a long length of several tens to several thousand meters by wefts 30 which are driven at intervals and connect the warps 20.

  The weft 30 can be woven (tuck-in method) by driving a single weft continuously by folding back at the side end of the woven fabric, or by driving a weft that has been cut back at both ends. The weft 30 driving interval does not cause problems in processing and handling such as adhesive treatment and heat treatment, and is within a range that facilitates the drawing operation of the warp yarn 20 from the interwoven fabric 2 after the treatment, for example, 10 to 100 mm. It can be set to a relatively large range.

  If the warp 20 and the weft 30 are firmly bonded to each other by the adhesive treatment, it may be difficult to separate the warp 20. Therefore, the weft 30 is subjected to a Teflon (registered trademark) coating process. The adhesiveness may be lowered.

  The interwoven fabric 2 thus woven can be easily subjected to treatments such as adhesive treatment and heat treatment required by ordinary means using a normal tire cord dipping machine.

  In the weave fabric 2 of the present invention, at both end portions a and b in the longitudinal direction of the fabric, the end portions of the warp yarn 20 are alternately joined at the end portions and both ends of the warp yarn 20 adjacent to one side thereof, so that a plurality of warp yarns are obtained. 20 is continuous. In the figure, 21 is an odd-numbered warp from one side end, 22 is an even-numbered warp from the side end, and 4 is the joint.

  As a specific form of joining of the warp yarns 20, as shown in FIG. 4, the end portions of the warp yarns 21 or 22 are arranged at one end portion a in the longitudinal direction of the fabric so that the warp yarns are alternately continued at both ends thereof. The warp 22 or 21 on either side of the two adjacent warps and the other warp 22 or 21 on the opposite side of the warps on the other end b in the longitudinal direction of the fabric. Are joined to the end of each.

  That is, at one end a in the fabric longitudinal direction, the end 21a of the odd-numbered warp 21 is joined to the end 22a of the next even-numbered warp 22 and at the other end b in the fabric longitudinal direction, The end 22b of the even-numbered warp 22 is joined to the end 21b of the next odd-numbered warp 21, and the warps 21 and 22 are alternately continued at both ends a and b.

  In the case of the interwoven fabric 2, the warps 21 and 22 are alternately joined at both ends thereof and are continuous into one. Therefore, a long tire cord in which all the warp yarns 20 are continuous is obtained by taking out the warp yarns 20 of the interwoven fabric 2 as cords by means such as sequentially pulling out from the side ends, and the manufacturing cost of the single cord is greatly reduced. can do.

  The joining at the warp end is performed in the same manner as in the first embodiment, that is, the end portions 21a and 22a and 21b and 22b at both ends of the warp are thermally melted, and the warps in the molten state are butt-melted. It is applied by stretching in the warp axis direction in a semi-solidified state, re-solidifying the joint 4 to a substantially circular cross section within a predetermined outer diameter range, and connecting the warp.

  As a result, the tire cord taken out from the interwoven fabric 2 becomes a long tire cord having a joining strength and a cord diameter comparable to the warp yarn 20 of the fabric main body portion at the joint portion 4, and cord breakage or the like in rubber topping processing. It is suitable for a tire reinforcing material that does not cause trouble.

  The joining at the warp end is preferably performed at the start of weaving in the weaving direction of the weave fabric 2 and at the end of weaving at the end of the end. It is also possible to perform bonding at an appropriate time after weaving and before and after treatment such as adhesive treatment.

  Further, the weave fabric 2 is generally formed with tabies 6a and 6b having a width of about 50 to 150 mm and a dense weft density of the wefts 30 at both ends at the beginning and end of weaving. Is extended from the tabby 6a, 6b to a required length, so that it is easy to implement the present invention by joining the warp ends.

[Modification]
6 and 7 show, as a modification of the joining form of the interwoven fabric 2, that any odd-numbered warp 21 counted from the side end and the even-numbered warp 22 adjacent thereto are joined at the end. In this case, the warp ends 21 and 22 are left as the non-joined ends 20a and 20b.

  6 shows a case where the end portions 21a and 22a of the non-joined warp yarns 21 and 22 are left as the non-joined end portions 20a at one end portion a in the longitudinal direction of the fabric, as shown in FIG. The soldering fabric 2b shows a case where the end 20a of the non-joined warp 20 is left at one end a in the longitudinal direction of the fabric and the end 20b of the unjoined warp 20 is left at the other end b.

  According to the weave fabrics 2a and 2b of this modification, by pulling out and taking out each warp 20 from the comb fabric in the same manner as in the second embodiment, a plurality of yarns separated at the non-joined portion at the end of the fabric ( In the case of the figure, a tire cord having a warp length of 3 or more) can be obtained.

  The location of the non-joined portion can be arbitrarily set according to the length and number of cords to be obtained from the braid fabrics 2a and 2b, and tire cords having different lengths can be taken out.

  As shown in FIG. 8, each of the above weave fabrics 2, 2a, 2b is usually wound in a roll shape after the treatment such as the adhesive treatment. At this time, the end portion 20c of the side warp 20 and the warp It is preferable that the 20 non-joining end portions 20a are wound so as to exist on the surface of the winding body 5 of the interwoven fabric 2. Thereby, for example, while pulling out the weave fabric 2 from the roll-shaped wound body 5, a method of taking out the warp 20 and obtaining a long tire cord can be easily implemented.

  Further, as shown in FIG. 9, the wound body 5 of the interwoven fabric 2 is supported by the support device 8 by releasing the one end side in the axial direction with the winding core 51 in the vertical direction, and the warp 20 is wound on the wound body. By pulling out from the upper end side of 5 in the axial direction, the warp yarns 20 can be successively drawn out from the side end portions of the interwoven fabric 2 and folded at the wound body end portion 52 to continuously take out the lower warp yarns 20. The removed warp 20 is wound around a bobbin 55 or the like through a rotatable guide member 54 and a guide roller 53. This extraction method can be easily implemented based on the method described in Japanese Patent Application Laid-Open No. 2000-199168.

  Furthermore, as shown in FIG. 10, two winding bodies 5a and 5b of the interwoven fabric 2 are vertically set with the winding core 51 as an axis, and both ends in the axial direction are released and supported by the support device 8 to be wound. The warp end 20d at the lowermost end of the wound body 5a and the warp end 20e at the uppermost end of the wound body 5b are joined by the joining portion 4a according to the joining method of the second embodiment, and the warp 20 is wound. By successively pulling out the upper end side of the body 5a in the axial direction, the warp yarn 20 can be continuously taken out from the interwoven fabric 2 of the two wound bodies 5a, 5b, and the production efficiency of the single cord is improved and more A long cord can be obtained.

  The long tire cords obtained as in the first and second embodiments are arranged by means such as passing the required number through a guide hole, and supplied to an extruder or calendar device to top the rubber. By doing so, it is possible to obtain a long topping sheet having no weft without causing troubles such as cord breakage and derailment from the calender roll groove during processing. For example, the pneumatic tire 7 shown in FIG. The carcass layer 71, the belt layer 72, the belt reinforcing layer 74, the belt end reinforcing layer 75, the side reinforcing layer 73, and the like can be suitably used as a tire reinforcing material that eliminates the adverse effects caused by the wefts. The topping sheet is made thinner by eliminating the step due to the weft between the warp and weft that occurs when the fabric is topped, contributing to weight reduction and cost reduction of the tire. It can be.

  The treated single tire cord is wound as it is in the tire molding process in a spiral shape at an angle of approximately 0 ° in the tire circumferential direction, and is then vulcanized and integrated by covering the tread and side rubber on it. Therefore, it can be used as a reinforcement cord such as a belt reinforcement layer 74, a belt end reinforcement layer 75, and a side reinforcement layer 73 that does not cause a joint portion in the tire circumferential direction.

  And when using the topping sheet or single cord as a tire reinforcing material, the joint strength and cord diameter of the cord are maintained at the same level as the main body cord. Performance such as durability and uniformity of the pneumatic tire can be ensured without causing an increase or loss of tire material.

  EXAMPLES The present invention will be further described below with reference to examples, but it goes without saying that the present invention is not limited to these examples.

[Example 1]
After two treated tire cords of nylon 66, 1400 dtex / 2 (twisted number 38 times / 10 cm) are cut at both ends of the cord as shown in FIG. 2, each tip is used with a commercially available cigarette lighter. Part (approx. 1 cm wide) to form a molten lump, then melt the molten lump together and fuse them together, slide the fused part with a fingertip fitted with rubber gloves and roll it into a substantially circular cross section The joint portion 13 was stretched and re-solidified to form a long tire cord shown in FIG.

  The cord diameter and tensile strength of the tire cord joint and main body were measured according to JIS L1017. The results are shown in Table 1.

  Furthermore, using a long tire cord having the same joint portions as described above every 150 m on average, as shown in the extruder base portion 9 in FIG. 12, a harmonica-shaped guide hole 95 in which a large number of cords 91 are arranged. Using a die throat 93 having a die, a die insert 92 for determining a rubber thickness, and a stealth stick system (manufactured by Stealth Stick, USA) equipped with an extruder (not shown) for supplying a topping rubber. It is processed into a topping sheet 94 having a thickness of 25 mm, a rubber thickness of 1.1 mm, and a sheet width of 10 cm, and this sheet is further slit along the cord into a width of 8 mm (including 7 cords) to form a tape-like reinforcing material for a belt reinforcing layer ( A) was prepared. In addition, a tape-shaped reinforcing material (B) was produced in the same manner using a tire cord having the same structure that does not include a joint, and the presence or absence of cord breakage and processability during topping processing of both cords with a stealth stick system were evaluated. The results are shown in Table 1.

  Using these tape-shaped reinforcing materials (A) and (B), the steel belt layer 72 of the pneumatic radial tire 7 shown in FIG. 11 is spirally jointless at an angle of approximately 0 ° with respect to the tire circumferential direction. Tires of size 205 / 65R15 in which the wound belt reinforcing layer 74 and belt end reinforcing layer 75 were formed were prototyped (referred to as tire A and tire B), and high-speed durability was evaluated according to the following test methods. The results are shown in Table 2.

  The carcass layer 71 was polyester, 1670 dtex / 2, one ply with a driving density of 23/25 mm, and the belt layer 72 was steel cord 2 + 2 × 0.25, two plies with a driving density of 20/25 mm.

  High-speed durability: Adjusted to 220 kPa air pressure using a standard rim, loaded with 85% of the standard load specified by JATMA, and started running at a speed of 140 km / hour using a drum testing machine equipped with a steel drum with a drum diameter of 1700 mm. The speed at the time of tire failure (Km / hour) was measured by increasing the speed by 10 km / hour every 10 minutes. The result was expressed as an index in which the speed at the time of failure occurrence was set with tire B as 100. Further, the tire after running was disassembled, and the failure state and the presence or absence of occurrence of cord breakage in the belt reinforcing layers 74 and 75 were observed.

  As is clear from Table 1, the cord diameter of the joint was slightly larger than that of the main body, but the joint cross-section was formed in a substantially circular shape and passed smoothly through the guide hole of the stealthic system during topping. Although strength was reduced by re-solidification, the cord strength of 85% of the main body was maintained, there was no cord breakage due to back tension during topping, and there was no problem in processability. Further, as shown in Table 2, tire A including the joint portion has sufficient high-speed durability as tire B including the joint portion by sufficiently securing the strength of the belt reinforcing layer, and the failure modes are both at the end of the steel belt. It can be seen that the separation due to the adhesion failure of the part and no cord breakage occurred, and the high-speed durability performance of the tire A is comparable to the tire B.

[Example 2]
In joining polyester and 1670 dtex / 2 (twisted 45 times / 10 cm) treated tire cord, as shown in FIG. 13, an ultrasonic oscillator 8 (US, Using a Bronson, E150 type, an ultrasonic wave is oscillated (output control scale 55, transmission time 0) with respect to the cord joint 86 placed with the tip of the cord superimposed on the groove 85 provided in the wooden base 84. 2 seconds), the cord terminals were fused to a length of 10 mm, and the fused portion was stretched to a length of 14 mm in a circular cross section and re-solidified to form a cord joint.

  The processed long tire cord which has the junction part joined by the said method every 200 m on average was produced. Using this cord, a stealth stick system was used to topp the sheet into a sheet having a cord driving density of 23/25 mm, a rubber thickness of 1.2 mm, and a sheet width of 20 cm. The carcass reinforcing material (C) was prepared by joining the sheet pieces cut into parallel and butt-jointed, and the carcass reinforcing material (D) was similarly prepared using the tire cord having the same structure not including the joint portion. . Using these carcass reinforcements (C) and (D), one-ply is applied to the carcass layer 71 of the pneumatic radial tire shown in FIG. 11, and tires of size 185 / 70R14 are prototyped (tires C and D). To do). The belt layer 72 was made of two plies of steel cord 2 + 2 × 0.25 and a driving density of 20 pieces / 25 mm.

  The presence or absence of cord breakage during the topping process of both cords and the processability were evaluated, and the high load durability of tires C and D was evaluated according to the following test method. The results are shown in Table 3.

  High load durability: A drum tester equipped with a steel drum with a drum diameter of 1700 mm, adjusted to a pneumatic pressure of 220 kPa using a standard rim, and loaded with 90% of the standard load specified by JATMA at a speed of 120 Km / hr. After running for 10 hours, the vehicle was run for 10 hours at 100% standard load and then for 22 hours at 110% standard load. If no failure occurred, the running time was extended and the vehicle was run until a tire failure occurred. . The distance traveled until the failure occurred was expressed as an index with tire D as 100, and the tire after running was disassembled and the failure state was observed.

  As shown in Table 3, there was no cord breakage during topping for both cords, and there was no problem in processability. In addition, tire C and tire D have almost the same high load durability, and the failure mode is due to adhesion failure (separation) of the carcass winding end, and the high load durability performance of tire C and tire D is It can be said that they are equivalent.

[Example 3]
Polyester, 1670 dtex / 2 (twisted 45 times / 10 cm) braided fabric with warp yarn (cord driving density 23/25 mm, anti-width 1 m, anti-length 500 m, weft is 30th cotton yarn, weft driving interval 2 cm) Was made.

  Next, RFL adhesive treatment and heat treatment were processed using a dipping machine according to a conventional method, and before and after this treatment, the ends of the warp yarns were joined together in the same manner as in Example 1 at both ends of the interwoven fabric. As shown in both ends of the interwoven fabric 2, a winding body of the interwoven fabric of the treated tire cord in which the joint portion is formed so that the warp of the entire fabric becomes a continuous cord is obtained.

  Next, from the wound body, the warp yarn was sequentially pulled out from the side end portion by the method shown in FIG. 9, and a long tire cord was taken out.

  In this tire cord taking-out operation, all warp yarns could be taken out as a single tire cord from the entire interwoven fabric without causing breakage of the cord or taking-out trouble at the joint.

  Further, a carcass reinforcing material (C) of Example 2 was produced using this tire cord. At this time, in the topping process using the stealth stick system, all cords could be topped without causing any trouble such as cord breakage. In other words, the tire cord obtained by taking out the warp from this weave fabric shows no abnormality such as a decrease in the strength of the cord joint or an increase in the cord gauge, which greatly increases the production efficiency of the single cord. It is possible to improve the cost of single code.

  As described above, the tire cord of the present invention is a long single tire cord that maintains the strength of the cord joint and the cord diameter in the same manner as the main body cord, and can efficiently produce a weft-free topping sheet. Therefore, it can be used as a reinforcing material for each part of a pneumatic tire such as a carcass, a belt, a belt reinforcing layer, and a sidewall. Of course, it can also be used as a reinforcing material for various rubber products such as industrial articles other than tires, vehicle articles, etc., such as industrial belts, air springs, and automotive flexible couplings.

It is a front view showing a tire cord of an embodiment. It is a schematic diagram explaining the joining method of the tire cord of embodiment. It is a schematic diagram explaining the other joining method of the tire cord of embodiment. It is the top view which abbreviate | omitted one part which shows the bamboo woven fabric of embodiment. It is an enlarged view same as the above. It is the top view which abbreviate | omitted one part which shows the interwoven fabric of other embodiment. It is the top view which abbreviate | omitted one part which shows the interwoven fabric of other embodiment. It is the perspective view which wound the interwoven fabric of embodiment of FIG. 5 in roll shape. It is a perspective view which shows the outline of the example of pulling out a warp. It is a perspective view which shows the outline of the other example of the method of taking out a warp. It is a half sectional view of a pneumatic radial tire. It is the schematic which shows the inside of an extruder die. It is the schematic which shows the melt | fusion part using an ultrasonic oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11,12 ... Tire cord 13 ... Joint part 14 ... Heating means 2,2a, 2b ... Banning fabric 4 ... Bonding fabric edge part 5 ... Roll wound body 7 ... Pneumatic radial tire 20 …… War warp 21 …… Odd number warp 22 …… Even number warp 30 …… Weft D0 …… Main body cord diameter D1 …… Joint cord diameter

Claims (6)

A tire cord in which two cords made of thermoplastic synthetic fibers are connected via a joint,
The joining portion is formed by thermally melting two cord terminal portions and fusing the heat-melting terminal portions together, and then extending the fused portion under a semi-solid state. Characteristic tire cord. At both ends in the longitudinal direction of a long weft fabric woven with warp yarns made of thermoplastic synthetic fiber tire cords, the end portions of the warp yarns are alternately joined with the end portions of the warp yarns adjacent to one side, A tire cord obtained by taking out the warp from a comb fabric made of continuous warps,
After joining the warp ends of the interwoven fabric, the two warp end portions are thermally melted, and the thermally melted end portions are fused to each other, and then the fused portion in a semi-solidified state is formed. A tire cord formed by stretching. The tire cord according to claim 1 or 2, wherein an outer diameter of the joint portion is 0.8 to 1.1 times as large as a main body portion cord diameter. The tire cord according to any one of claims 1 to 3, wherein a cross-sectional shape of the joint portion is formed in a substantially circular shape. The tire cord according to any one of claims 1 to 4, wherein a cord strength at the joint portion is 60% or more of a body portion cord strength. A pneumatic tire reinforced with the tire cord according to any one of claims 1 to 5.

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