Tire cord, method for manufacturing the same and tire comprising the same

Abstract

The present invention relates to a tire cord, a method for manufacturing the same, and a tire comprising the same. The tire cord has excellent durability and thin thickness, can be used for a cap layer, a belt layer, a carcass, etc. of a tire, has excellent adhesion to rubber, and can be easily bonded to rubber even without an existing rolling process.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2019-0175655 filed in the Korean Intellectual Property Office on December 26, 2019, and Korean Patent Application No. 10-2020-0176538 filed in the Korean Intellectual Property Office on December 16, 2020, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0004] The present invention relates to a tire cord, a method for manufacturing the same and a tire comprising the same. Background Art

[0005] Recently, as vehicle performance and road conditions improve, driving speeds are getting faster and faster. Therefore, the stability and durability of tires must be maintained even when driving at high speeds. For this reason, many studies have been actively conducted on tire cords used as reinforcing materials for tire rubber.

[0006] Tire cord can be roughly divided into carcass, belt and cap ply according to the parts and rules used. The materials used for this include nylon, rayon, aramid and polyester including PET.

[0007] At this time, the tire cord composed of the above-mentioned materials is generally rolled together with the rubber component to be bonded to the rubber. That is, a rolling process is included in the tire manufacturing process. In this way, when the rolling process for bonding the tire cord to the rubber is applied in the tire manufacturing process, the process cost increases, and due to the rolling, the density of the tire is unnecessarily increased, thereby unnecessarily increasing the weight of the tire.

[0008] In addition, in the process of rolling rubber on tire cord, solid rubber is generally used. Products formed by rolling such solid rubber are difficult to be made into films of less than 200 μm, specifically 5 μm to 30 μm. When these products are used as reinforcing materials, the thickness and weight of the tire increase.

[0009] On the other hand, recently, tire manufacturers have tried to reduce the thickness of the rubber layer in order to make the tire ultra-lightweight and reduce the weight of the reinforcement material. The rolling resistance (R / R) is related to the weight of the tire and has a significant impact on the fuel consumption and carbon dioxide emissions of the vehicle. For example, the greater the rolling resistance (R / R), the higher the energy required to drive the vehicle. In addition, the resistance of the vehicle to rotation, tilt and acceleration is closely related to the weight of the vehicle. Therefore, it is also being studied to reduce the weight of the vehicle by reducing the weight of the tire, thereby reducing energy consumption.

[0010] Therefore, there is a need to develop a new tire cord which exhibits excellent adhesion to rubber while being thin in thickness. Summary of the invention

[0011] Technical issues

[0012] An object of the present invention is to provide a tire cord having excellent durability while being thin in thickness.

[0013] Another object of the present invention is to provide a method for manufacturing a tire cord having excellent durability while being thin in thickness.

[0014] Still another object of the present invention is to provide a tire including the tire cord.

[0015] Technical Solution

[0016] Provided herein is a tire cord, comprising: a fiber base woven with warp yarns comprising at least one of nylon, rayon, aramid, and polyester comprising PET at a warp yarn density of 65% or more, or a number of warp yarns per unit length (n / inch) of 35 or more; an adhesive layer formed on the fiber base; and a rubber coating layer formed on the adhesive layer, wherein the rubber coating layer comprises synthetic rubber or natural rubber, and wherein the coating amount per unit area of ​​the rubber coating layer to the adhesive layer is 75 g / m 2 Up to 300g / m 2 .

[0017] Also provided herein is a method for manufacturing a tire cord, comprising the following steps: preparing a fiber base woven with warp yarns comprising at least one of nylon, rayon, aromatic polyamide, and polyester comprising PET at a warp yarn density of 65% or more, or a number of warp yarns per unit length (n / inch) of 35 or more; forming an adhesive layer on the fiber base; and applying a rubber coating solution on the adhesive layer and heat-treating it to form a rubber coating, wherein the rubber coating comprises synthetic rubber or natural rubber, and wherein the coating amount of the rubber coating on the adhesive layer per unit area is 75 g / m 2 Up to 300g / m 2 .

[0018] Also provided herein is a tire comprising the above tire cord.

[0019] Now, a tire cord, a method for manufacturing the same, and a tire including the same according to specific embodiments of the present invention will be described in detail.

[0020] As used herein, the terms "warp" and "weft" refer to the construction of a fiber base as a component of a tire cord for interlacing these yarns. The orientation of each yarn related to the interlacing may be relative to each other, and therefore, the weft and warp may also be relative names to each other.

[0021] The technical terms used herein are only used for reference to specific embodiments and are not intended to limit the present invention. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "the" used herein include plural references. It should also be understood that the terms "including", "comprising", "having" and the like used herein specify the presence of the described features, integers, steps, constituent elements and / or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, steps, constituent elements and / or combinations thereof.

[0022] The present invention may include various modifications and may be implemented in many different forms, and specific embodiments of the present invention will now be provided and described in detail. However, this is not intended to limit the present invention to specifically disclosed forms, and it should be understood that all modifications, equivalents or replacements may be made to the present invention without departing from the technical concept and scope of the present invention.

[0023] In one embodiment, the present invention is directed to a tire cord.

[0024] Specifically, according to one embodiment of the present invention, there can be provided a tire cord, comprising: a fiber base, the fiber base being woven with warp yarns comprising at least one of nylon, rayon, aromatic polyamide and polyester comprising PET at a warp yarn density of 65% or more, or a number of warp yarns per unit length (n / inch) of 35 or more; an adhesive layer formed on the fiber base; and a rubber coating layer formed on the adhesive layer, wherein the rubber coating layer comprises synthetic rubber or natural rubber, and wherein the coating amount per unit area of ​​the rubber coating layer to the adhesive layer is 75 g / m 2 Up to 300g / m 2 .

[0025] The present inventors have studied tire cords and confirmed through experiments that a tire cord including the above-mentioned components has excellent durability while being thin, thereby completing the present invention.

[0026] In addition, since the tire cord of the above embodiment has excellent adhesion to rubber, it can be firmly bonded to rubber without a rolling process during tire manufacturing. Without a rolling process, the manufacturing cost of the tire is reduced, the density of the tire is prevented from being unnecessarily increased due to rolling, and the weight of the tire is prevented from being unnecessarily increased.

[0027] When the tire cord of the above embodiment is used as a tire cap layer, a belt layer, a carcass, etc., the rolling process can be omitted, thereby simplifying the tire manufacturing process, and reducing the tire thickness and total weight. In addition, since the viscosity of the tire cord is greatly increased, cavitation is reduced during the manufacturing process of the green tire, thereby reducing the tire defect rate.

[0028] In addition, when the tire cord of the above embodiment is used in a tire, since the tire cord has excellent rubber reinforcement performance and a thin thickness, the tire weight is reduced and the rolling resistance (R / R) is reduced, which not only improves the fuel efficiency of the vehicle but also reduces carbon dioxide emissions.

[0029] The tire cord of the embodiment includes a fiber base, and the fiber base can use filaments including at least one of nylon, rayon, aramid, and polyester including PET as warp yarns. At this time, the warp yarns are used for weaving, wherein the weaving can be performed with a warp density of 65% or more or a warp number per unit length (n / inch) of 35 or more.

[0030] The inter-warp density indicates the area occupied by the warp yarns per inch, and specifically, can be expressed as {(width of one warp yarn (inch) × number of warp yarns per inch (n)) / inch} × 100 (%). Width can be used synonymously with amplitude, and in the case of tire cord, its cross section is substantially circular, and therefore, width can be used interchangeably with thickness.

[0031] In an exemplary embodiment, the lower limit of the density between warps may be 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, or 95% or more. In addition, there is no particular limitation on the upper limit of the density between warps, but for example, it may be less than 100%, specifically 99% or less, 98% or less, 97% or less, 96% or less, or 95% or less. When the range of the density between warps satisfies the above range, a stable adhesive layer can be formed and fatigue performance can be ensured, and it plays a role in improving the bonding strength with the rubber coating. In particular, when the density between warps is less than 65%, there is a problem that the bonding strength is unstable and the rubber coating flows downward.

[0032] In an exemplary embodiment, the number of warps per unit length (n / inch) may be 35 or more, 40 or more, 45 or more, 50 or more, 55 or more, 60 or more, or 65 or more. In addition, the upper limit of the number of warps per unit area is not particularly limited, but for example, may be 90 or less, 85 or less, 80 or less, 75 or less, 70 or less, 65 or less, or 60 or less. When the number of warps per unit area satisfies the above range, a stable adhesive layer may be formed, fatigue performance may be ensured, and the bonding strength with the rubber coating may be improved. In particular, when the number of warps per unit length is less than 35, there is a problem that the bonding strength is unstable and the rubber coating flows downward.

[0033] In an exemplary embodiment, the fiber base may be a fiber base woven with a warp density of 65% or more and, at the same time, a number of warps per unit length (n / inch) of 35 or more. When the warp density and the number of warps are satisfied at the same time, the above-mentioned adhesive strength, bonding strength and fatigue resistance can be more stably ensured. The specific warp density and the number of warps are the same as described above.

[0034] In an exemplary embodiment, the inter-weft density of the fiber base may be lower than the inter-warp density. Similar to the above-mentioned inter-warp density, the inter-weft density represents the area occupied by the weft yarns per inch, and specifically, can be confirmed as {(width of a weft yarn (inch) × number of weft yarns per inch (n)) / inch} × 100 (%).

[0035] In an exemplary embodiment, the weft density of the fiber substrate can be in the range of 3% to 25%. Specifically, the lower limit of the weft density of the fiber substrate can be, for example, more than 4%, more than 5%, more than 6%, more than 7%, more than 8%, more than 9%, more than 10%, more than 11%, more than 12%, more than 13%, more than 14%, or more than 15%. In addition, the upper limit of the weft density of the fiber substrate can be, for example, less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, less than 13%, less than 12%, less than 11%, or less than 10%. When the weft density is less than the above range, the warp yarn cannot be stably supported during heat treatment or rubber coating, thereby, the fabric is twisted and defects will occur. In addition, when the weft density exceeds the above range, it will become difficult to adjust the width of the product during heat treatment, and the bonding strength will become relatively low. The reason why the bonding strength becomes low is that in tire manufacturing, the weft yarn is used to support the warp yarn and at the same time acts as a channel for the gas in the rubber to escape, but when excessive weft yarn is used, it acts as a foreign body inside the tire to a certain extent, and the area where the warp yarn contacts the rubber is reduced.

[0036] In an illustrative example, the number of weft yarns per unit length (n / inch) of the fibrous base may be lower than the number of weft yarns per unit length.

[0037] In an exemplary embodiment, the number of wefts of the fiber base may be in the range of 5 to 30 (number of wefts per unit length: n / inch). Specifically, the lower limit of the number of wefts of the fiber base may be, for example, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 11 or more, 12 or more, 13 or more, 14 or more, 15 or more, 16 or more, 17 or more, 18 or more, 19 or more, or 20 or more. In addition, the upper limit of the number of wefts of the fiber base may be, for example, 29 or less, 28 or less, 27 or less, 26 or less, 25 or less, 24 or less, 23 or less, 22 or less, 21 or less, 20 or less, 19 or less, 18 or less, 17 or less, 16 or less, or 15 or less. When the number of wefts is less than the above range, the warp yarns cannot be stably supported during the heat treatment or rubber coating process, whereby the fabric is twisted and defects may occur. In addition, when the number of wefts exceeds the above range, it becomes difficult to adjust the width of the product during the heat treatment process, and the bonding strength becomes relatively low. The reason why the bonding strength becomes low is that in tire manufacturing, the weft yarn is used to support the warp yarn and at the same time acts as a channel for the gas in the rubber to escape, but when excessive weft yarn is used, it acts as a foreign body inside the tire to a certain extent, and the area where the warp yarn contacts the rubber is reduced.

[0038] On the other hand, twist may be imparted to the warp yarns.

[0039] At this time, the twist unit is TPM and is defined as the number of twists per meter, and the twist may be twisted at 0 TPM to a maximum of 250 TPM based on the number of twists per 1 m.

[0040] When twist is given to the warp yarn, it can play a role in improving the bundling performance of the tire cord and improving the fatigue performance.

[0041] In an exemplary embodiment, the fineness of the fiber (warp and / or weft) including at least one of nylon, rayon, aramid, and polyester including PET may be 300 de to 1500 de. Specifically, the lower limit of the fineness may be 350 de or more, 400 de or more, 450 de or more, 500 de or more, 550 de or more, 600 de or more, 650 de or more, 700 de or more, 750 de or more, 800 de or more, 850 de or more, 900 de or more, 950 de or more, 1000 de or more, 1050 de or more, 1100 de or more, 1150 de or more, or 1200 de or more. In addition, the upper limit of the fineness can be, for example, 1450de or less, 1400de or less, 1350de or less, 1300de or less, 1250de or less, 1200de or less, 1150de or less, 1100de or less, 1050de or less, 1000de or less, 950de or less, 900de or less, 850de or less, 800de or less, 750de or less, or 700de or less.

[0042] For example, a warp yarn imparting a twist of 0 to 250 TPM to a filament including at least one of rayon, aramid, and polyester including PET having a fineness of 300 to 1500 de may be used.

[0043] Meanwhile, the thickness of the fiber substrate of the embodiment can be, for example, more than 0.10mm, more than 0.15mm, more than 0.20mm, more than 0.25mm, more than 0.30mm, more than 0.35mm or more than 0.40mm. In addition, the upper limit of the thickness can be, for example, less than 0.60mm, less than 0.55mm, less than 0.50mm, less than 0.45mm or less than 0.40mm. When the fiber substrate has a thickness within the above range, a stable adhesive layer with constant strength and elongation at break can be formed.

[0044] Meanwhile, the tire cord of the embodiment may include an adhesive layer formed on the above-mentioned fiber base.

[0045] The adhesive layer may include resorcinol-formaldehyde-latex (RFL).For example, the adhesive layer may be formed of an adhesive coating solution including resorcinol-formaldehyde-latex (RFL) and a solvent.

[0046] Resorcinol-formaldehyde-latex is also referred to as "RFL" and can act as an adhesive component. Resorcinol-formaldehyde-latex can specifically improve the affinity and bonding strength between the fiber base and the rubber component, and improve the bonding strength between the fiber base and the rubber coating in the tire cord.

[0047] Therefore, the fiber base and the rubber coating in the tire cord can be stably adhered without being separated from each other. When the above tire cord is applied to a tire, defects can be prevented from occurring during the manufacturing process of the tire. In addition, after the vulcanization process, the tire cord and the rubber (e.g., tread, etc.) can be bonded together in the finished tire to maintain excellent bonding strength.

[0048] Meanwhile, the tire cord of the embodiment may include a rubber coating layer formed on the adhesive layer.

[0049] At this time, the rubber coating layer can be formed by applying a rubber coating solution to the adhesive layer, but can have a thin rubber coating layer that is difficult to achieve by a rolling process using solid rubber. As the thickness of the rubber coating layer becomes thinner, it can also contribute to the weight reduction of the tire cord including it and the tire including the tire cord.

[0050] Specifically, the rubber coating layer may be formed of a rubber coating solution including an elastomeric polymer composition including synthetic rubber or natural rubber and a solvent, and the elastomeric polymer composition may include an elastic polymer and additives.

[0051] For example, the elastomeric polymer composition may include at least one elastomeric polymer selected from natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), chloroprene rubber (CR), isobutylene rubber (IBR), isoprene rubber (IR), nitrile rubber (NBR), butyl rubber and chloroprene rubber.

[0052] In addition, the additive may include, for example, carbon black, paraoil, zinc oxide, stearic acid, an anti-aging agent, sulfur, a vulcanization accelerator, an active agent, a cohesive agent, a binder, and the like.

[0053] The type of the solvent is not particularly limited as long as it is a substance capable of dissolving the elastomeric polymer. For example, the solvent may include at least one selected from toluene, naphtha, methanol, xylene, and tetrahydrofuran.

[0054] Meanwhile, the rubber coating solution may include: 10 wt % to 30 wt % of the elastomeric polymer composition; and 70 wt % to 90 wt % of the solvent.

[0055] When the concentration of the elastomeric polymer composition in the rubber coating solution is less than 10 wt %, the thickness of the rubber coating becomes thin and cannot exhibit appropriate tack and adhesive strength, which causes problems such as degradation of tire manufacturing characteristics and tire defects during driving.

[0056] Meanwhile, when the concentration of the elastomeric polymer composition in the rubber coating solution exceeds 30 wt %, the stirring performance decreases due to increased viscosity, and the dispersibility of the rubber coating solution decreases, whereby the coating performance decreases and the coating thickness may be uneven.

[0057] At the same time, the coating amount of the rubber coating layer per unit area of ​​the adhesive layer can be 75 g / m 2 Up to 300g / m 2 , but when the coating amount per unit area of ​​the rubber coating layer to the adhesive layer is adjusted within the above range, a tire cord having excellent adhesion to rubber and excellent durability while being thin in thickness can be provided. Specifically, the lower limit of the coating amount per unit area of ​​the rubber coating layer to the adhesive layer can be, for example, 80 g / m 2 Above, 85g / m 2 Above, 90g / m 2 Above, 95g / m 2 Above, 100g / m 2 Above, 105g / m 2 Above, 110g / m 2 Above, 115g / m 2 Above, 120g / m 2 Above, 125g / m 2 Above, 130g / m 2 Above, 135g / m 2 Above, 140g / m 2 Above, 145g / m 2 Above, 150g / m 2 Above, 155g / m 2 Above, 160g / m 2 Above, 165g / m 2 Above, 170g / m 2 Above, 175g / m 2 Above, 180g / m 2 Above, 185g / m 2 Above, 190g / m 2 Above, 195g / m 2 Above or 200g / m 2 In addition, the upper limit of the coating amount of the rubber coating can be, for example, 290 g / m 2 Below, 280g / m 2 Below, 270g / m 2 Below, 260g / m 2 Below, 250g / m 2 Below, 240g / m 2 Below, 230g / m 2Below, 220g / m 2 Below, 210g / m 2 Below, 200g / m 2 Below, 190g / m 2 Below, 180g / m 2 Below, 170g / m 2 Below or 160g / m 2 the following.

[0058] When the rubber coating amount per unit area of ​​the rubber coating layer to the adhesive layer is less than the above range, voids may be generated on the rubber surface, or problems such as deterioration of tire quality may occur when the tire cord is used to manufacture a tire. In addition, when the coating amount exceeds the above range, the tire weight increases and the rolling resistance (R / R) increases, thereby not only reducing the fuel efficiency of the vehicle but also increasing carbon dioxide emissions.

[0059] Meanwhile, the thickness of the rubber coating layer may be 0.01 mm to 0.20 mm, or 0.02 mm to 0.20 mm, or 0.04 mm to 0.10 mm.

[0060] Since a rubber base is rolled on a fiber base to form a rubber layer, a conventional tire cord generally has a thickness of 1 mm or more, and the thickness is at least 0.8 mm or more.

[0061] Meanwhile, since the rubber coating of the above embodiment is formed by a rubber coating solution, it can have a thin thickness of 0.2 mm or less. Therefore, the overall thickness of the tire cord can be thinned, and further, the thickness of the tire including the tire cord can be thinned.

[0062] When the thickness of the rubber coating layer is less than 0.01 mm, the rubber coating layer does not have sufficient tack and adhesive strength, and therefore, when the tire cord is applied to a tire, tire manufacturing characteristics deteriorate, it becomes difficult to exhibit tire durability, and tire defects may occur.

[0063] When the thickness of the rubber coating exceeds 0.20 mm, the thickness of the tire cord increases, and therefore, the thickness of the tire increases. In particular, during the volatilization of the solvent, bubbles are generated in the rubber coating, which makes it difficult for the tire cord to have a uniform thickness. When it is applied to a tire, air pockets appear in the tire, which causes a decrease in tire quality and an increase in defect rate. In addition, there is a disadvantage that multiple coating operations must be performed in order to form a thick rubber coating, which is inefficient in the process and can cause a decrease in tire quality and a defect rate.

[0064] Meanwhile, the tire cord may have a breaking strength measured according to a standard test method of ASTM D885 of 2.0 g / d to 15.0 g / d, or 8.0 g / d to 13.0 g / d.

[0065] In addition, the tire cord may have an elongation at break measured according to the standard test method of ASTM D885 of 10% to 30%, or 20% to 25%.

[0066] In addition, when the adhesive strength is evaluated according to the standard test method of ASTM D4393, the adhesive strength of the tire cord may be 10 kgf or more or 15 kgf or more.

[0067] In an exemplary embodiment, the tire cord may have a 1-strand structure. That is, the tire cord may be a tire cord manufactured by twisting one strand of the above-mentioned yarn. In the case of the 1-strand structure, the thin thickness of the tire cord is advantageously ensured and the weight is reduced. In addition, the above-mentioned density and number related to the warp and weft yarns are advantageously satisfied.

[0068] In another example, the invention is directed to a method of making a tire cord.

[0069] Specifically, according to another embodiment of the present invention, a method for manufacturing a tire cord can be provided, comprising the following steps: preparing a fiber base, the fiber base being woven with warp yarns including at least one of nylon, rayon, aromatic polyamide and polyester including PET at a warp yarn density of 65% or more, or a number of warp yarns per unit length (n / inch) of 35 or more; forming an adhesive layer on the fiber base; and applying a rubber coating solution on the adhesive layer and heat-treating it to form a rubber coating, wherein the rubber coating comprises synthetic rubber or natural rubber, and wherein the coating amount of the rubber coating to the adhesive layer per unit area is 75 g / m 2 Up to 300g / m 2 .

[0070] The contents of the fiber substrate include those described above with respect to one embodiment.

[0071] Meanwhile, before the step of preparing the fiber base using the warp yarn, a step of imparting twist to the warp yarn including at least one of nylon, rayon, aramid, and polyester including PET may be further included.

[0072] The twist can be applied from 0 TPM to a maximum of 250 TPM based on the number of twists per 1 m.

[0073] As described above, regarding the twist of the fiber, the production method of the present invention can prepare a one-ply structure by twisting one ply of yarn.

[0074] At the same time, an adhesive layer can be formed on the fiber substrate, and the adhesive layer can be formed by an adhesive coating solution containing resorcinol-formaldehyde-latex (RFL) and a solvent. At this time, the step of forming the adhesive layer can include applying the adhesive coating solution to the fiber substrate and performing a heat treatment.

[0075] There is no particular limitation on the method of applying the adhesive coating solution to the fiber substrate. For example, the adhesive coating solution can be applied to the fiber substrate by dipping the fiber substrate in the adhesive coating solution. Alternatively, the impregnation process can be performed by passing the fiber substrate through the adhesive coating solution. The impregnation process can be performed using an impregnator in which the tension, impregnation time and temperature can be adjusted.

[0076] In addition, the adhesive coating solution may be applied to the fiber substrate by coating using a doctor blade or a coater, or spraying using a syringe, other than the dipping process.

[0077] At the same time, the step of forming the adhesive layer may also include applying the adhesive coating solution to the fiber substrate and heat treating it at 130° C. to 250° C. for 80 seconds to 120 seconds. At this time, the heat treatment may be performed using a heat treatment device. Resorcinol-formaldehyde-latex (RFL) is cured and fixed by the heat treatment to complete the adhesive layer. By this heat treatment, the adhesive layer can be formed more stably.

[0078] Meanwhile, after the adhesive layer is formed, a rubber coating solution may be applied to the adhesive layer and heat-treated to form a rubber coating layer on the adhesive layer.

[0079] The rubber coating solution comprises an elastomeric polymer composition and a solvent. The elastomeric polymer composition may comprise an elastomeric polymer and additives.

[0080] For example, the elastomeric polymer composition may include at least one elastomeric polymer selected from natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), chloroprene rubber (CR), isobutylene rubber (IBR), isoprene rubber (IR), nitrile rubber (NBR), butyl rubber and chloroprene rubber.

[0081] In addition, the additive may include, for example, carbon black, paraoil, zinc oxide, stearic acid, an anti-aging agent, sulfur, a vulcanization accelerator, an active agent, a cohesive agent, a binder, and the like.

[0082] The type of the solvent is not particularly limited as long as it is a substance capable of dissolving the elastomeric polymer. For example, the solvent may include at least one selected from toluene, naphtha, methanol, xylene, and tetrahydrofuran.

[0083] Meanwhile, the rubber coating solution includes 10 to 30 wt % of the elastomeric polymer composition and 70 to 90 wt % of the solvent, based on the total weight of the rubber coating solution.

[0084] When the concentration of the elastomeric polymer composition in the rubber coating solution is less than 10 wt %, the thickness of the rubber coating becomes thin and cannot exhibit appropriate tack and adhesive strength, which causes problems such as degradation of tire manufacturing characteristics and tire defects during driving.

[0085] Meanwhile, when the concentration of the elastomeric polymer composition in the rubber coating solution exceeds 30 wt %, the stirring performance decreases due to increased viscosity, and the dispersibility of the rubber coating solution decreases, whereby the coating performance decreases and the coating thickness may be uneven.

[0086] Meanwhile, the method of applying the rubber coating solution onto the adhesive layer is not particularly limited, and a known coating method may be used.

[0087] For example, in order to form the rubber coating, the fiber substrate coated with the adhesive layer can be immersed in the rubber coating solution. Through this dipping, the rubber coating solution can be applied to the adhesive layer.

[0088] The coating method includes gravure coating, micro gravure coating, comma coating, etc. For example, the rubber coating solution can be coated on the adhesive layer by comma coating using a comma coater. At this time, the coating can be performed under a temperature condition of 65° C. to 100° C., which corresponds to the lowest temperature at which the solvent can volatilize.

[0089] At the same time, the step of applying a rubber coating solution onto the adhesive layer and then performing a heat treatment may be further included.

[0090] At this time, the heat treatment may be performed by a heat treatment device. For the heat treatment, heating may be performed at a temperature of 50° C. to 160° C. for 30 seconds to 150 seconds.

[0091] At the same time, the coating amount per unit area of ​​the rubber coating can be 75g / m 2 Up to 300g / m 2 , and the coating amount per unit area of ​​the rubber coating layer to the adhesive layer can be adjusted within the above range, thereby manufacturing a tire cord having excellent adhesion to rubber and excellent durability while having a thin thickness. The specific coating amount is as described above.

[0092] Meanwhile, the thickness of the rubber coating layer may be 0.01 mm to 0.20 mm, or 0.02 mm to 0.20 mm, or 0.04 mm to 0.10 mm. When the thickness of the rubber coating layer is less than 0.01 mm, the rubber coating layer does not have sufficient viscosity and adhesion, and therefore, the tire manufacturing characteristics are deteriorated, and in addition, tire defects may occur. In addition, when the thickness of the rubber coating layer exceeds 0.20 mm, the thickness of the tire cord may increase, causing an increase in the thickness of the tire.

[0093] Meanwhile, after the rubber coating layer is formed, a slitting step may be optionally performed.

[0094] The method may also include a step of cutting the tire cord prepared in a plate shape to meet the purpose of use or to meet the needs. This cutting is called longitudinal cutting. The longitudinal cutting step can be omitted. There is no particular restriction on the method of cutting or longitudinal cutting.

[0095] For example, slitting can be performed by cutting the tire cord using a conventional cutting knife or a heated knife.

[0096] Meanwhile, the tire cord manufactured by the manufacturing method may be wound on a winder.

[0097] In yet another embodiment, the present invention is directed to a tire.

[0098] More specifically, according to still another embodiment of the present invention, there may be provided a tire including the above-mentioned tire cord.

[0099] The tire cord can be applied to at least one of a cap layer, a belt layer, and a carcass of a tire. The tire cord has excellent adhesion to rubber and can be easily bonded to rubber without a rolling process.

[0100] When the tire cord is used as a cap layer, the rolling process can be omitted, thereby simplifying the tire manufacturing process and greatly increasing the viscosity of the cap layer. Therefore, when manufacturing a green tire, air pockets are reduced, thereby reducing the defect rate of the tire. In addition, since the rolling process is not performed, a thin and light tire can be manufactured.

[0101] Beneficial Effects

[0102] According to the present invention, a tire cord having excellent durability and thin thickness can be provided.

[0103] Furthermore, according to the present invention, a method for producing a tire cord having excellent durability and a thin thickness can be provided.

[0104] Furthermore, according to the present invention, there can be provided a tire including the tire cord. Specific implementation plan

[0105] Hereinafter, the present invention will be described in more detail by the following examples. However, these examples are provided only for illustrative purposes, and the scope of the present invention is not limited thereto.

[0106] Examples and Comparative Examples

[0107] Example 1

[0108] A fiber base (thickness: about 0.40 mm) with a total fineness of 630 de nylon and a twist of 200 TPM was woven with a warp number (n / inch) of 58 and a warp density of 90%. At this time, the weft number (n / inch) was 8 and the weft density was 4.8%.

[0109] Next, the fiber base was immersed in an adhesive coating solution containing 15 wt % of resorcinol-formaldehyde-latex (RFL) and 85 wt % of a solvent (water, H 2 O), and then heat-treated at 150° C. for 100 seconds to form an adhesive layer.

[0110] Next, the rubber coating was applied using a comma coater at a coating amount of 120 g / m 2 Up to 130g / m 2 The adhesive layer was coated, and the solvent was volatilized at a temperature of 70° C. Thus, a tire cord in which a rubber coating layer having a thickness of 0.04 mm to 0.05 mm was formed was manufactured.

[0111] At this time, a rubber coating layer is formed by applying a rubber coating solution onto the adhesive layer, and an elastomeric polymer composition based on 100 parts by weight of styrene butadiene rubber (SBR) and natural rubber, comprising 20 to 50 parts by weight of carbon black, 5 to 10 parts by weight of para oil, 2 to 8 parts by weight of zinc oxide, 2 to 8 parts by weight of stearic acid, 1 to 5 parts by weight of an anti-aging agent (RUBBER ANTIOXIDANTS, BHT), 2 to 8 parts by weight of sulfur and 1 to 3 parts by weight of a vulcanization accelerator (ZnBX) is dispersed in 100 parts by weight of a toluene solvent at a concentration of 20% to 40% to prepare a rubber coating solution.

[0112] Example 2

[0113] A twist of 150 TPM was imparted to nylon having a total fineness of 1260 de, and a fiber base having a warp yarn number (n / inch) of 42 and a warp density of 84% was woven.

[0114] Next, the fiber base was immersed in an adhesive coating solution containing 15 wt % of resorcinol-formaldehyde-latex (RFL) and 85 wt % of a solvent (water, H 2 O), and then heat-treated at 150° C. for 100 seconds to form an adhesive layer.

[0115] Next, the rubber coating was applied using a comma coater at a coating amount of 130 g / m 2 Up to 140g / m 2 The adhesive layer was coated, and the solvent was volatilized at a temperature of 70° C. Thus, a tire cord in which a rubber coating layer having a thickness of 0.06 mm to 0.07 mm was formed was manufactured.

[0116] At this time, the same rubber coating solution as in Example 1 was used for the rubber coating, and a tire cord was manufactured in the same manner as in Example 1.

[0117] Example 3

[0118] A twist of 150 TPM was imparted to PET having a total fineness of 800 de, and a fiber base having a warp yarn number (n / inch) of 50 and a warp density of 71% was woven.

[0119] Next, the fiber base was immersed in an adhesive coating solution containing 15 wt % of resorcinol-formaldehyde-latex (RFL) and 85 wt % of a solvent (water, H 2 O), and then heat-treated at 150° C. for 100 seconds to form an adhesive layer.

[0120] Next, the rubber coating was applied using a comma coater at a coating amount of 150 g / m 2 Up to 160g / m 2 The adhesive layer was coated, and the solvent was volatilized at a temperature of 70° C. Thus, a tire cord in which a rubber coating layer having a thickness of 0.07 mm to 0.08 mm was formed was manufactured.

[0121] At this time, the same rubber coating solution as in Example 1 was used for the rubber coating, and a tire cord was manufactured in the same manner as in Example 1.

[0122] Comparative Example 1

[0123] A tire cord and a tire were manufactured in the same manner as in Example 1, except that a twist of 200 TPM was given to nylon having a total fineness of 630 de and a fiber base having a warp number (n / inch) of 34 and a warp density of 53% was used.

[0124] Comparative Example 2

[0125] A tire cord and a tire were manufactured in the same manner as in Example 1, except that a twist of 150 TPM was given to nylon having a total fineness of 1260 de and a fiber base having a warp number (n / inch) of 30 and a warp density of 60% was used.

[0126] Comparative Example 3

[0127] A tire cord and a tire were manufactured in the same manner as in Example 1, except that a twist of 150 TPM was given to PET having a total fineness of 800 de and a fiber base having a warp number (n / inch) of 34 and a warp density of 47% was used.

[0128] Comparative Example 4

[0129] In addition to using a comma coater to apply the rubber coating at a coating weight of 45 g / m per unit area, 2 Up to 50g / m 2 A tire cord was manufactured in the same manner as in Example 1, except that the rubber coating layer was coated on the adhesive layer and the solvent was volatilized at a temperature of 70° C. to form a rubber coating layer having a thickness of 0.01 mm to 0.02 mm.

[0130] Comparative Example 5

[0131] In addition to using a comma coater to apply the rubber coating at a coating weight of 65g / m 2 Up to 70g / m 2 A tire cord was manufactured in the same manner as in Example 2 except that the rubber coating layer was coated on the adhesive layer and the solvent was volatilized at a temperature of 70° C. to form a rubber coating layer having a thickness of 0.02 mm.

[0132] Comparative Example 6

[0133] In addition to using a comma coater to apply the rubber coating at a coating weight of 65g / m 2 Up to 70g / m 2 A tire cord was produced in the same manner as in Example 3 except that the rubber coating layer was applied onto the adhesive layer and the solvent was volatilized at a temperature of 70° C. to form a rubber coating layer having a thickness of 0.02 mm.

[0134] Experimental example

[0135] Experimental Example 1: Measurement of breaking strength and breaking elongation

[0136] The breaking strength and breaking elongation of the tire cord were measured using an Instron tester (Instron Engineering Corp., Canton, Mass.) by applying a tensile speed of 300 m / min to 10 samples of 250 mm (width 10 mm×length 250 mm) according to the test method of ASTM D885.

[0137] Then, the breaking strength is divided by the total fineness of the tire cord to obtain the breaking strength (g / d) of each sample. Then, the breaking strength and elongation at break of the tire cord with rubber coating are obtained by calculating the average value of the breaking strength and elongation at break of 10 samples. In addition, the elongation under a load of 4.5kgf and a load of 6.8kgf are measured respectively.

[0138] [Table 1]

[0139]

[0140] According to Table 1, it can be confirmed that when the tire cords according to the Examples of the present invention are used, they exhibit excellent characteristics in terms of strength, breaking strength, and breaking elongation, compared with the Comparative Examples.

[0141] Experimental Example 2: Measurement of Adhesion Strength

[0142] The adhesive peel strength of the tire cords prepared in Examples and Comparative Examples on the carcass layer of the tire was measured according to the test method of ASTM D4393.

[0143] Specifically, a 0.6 mm thick rubber sheet, a cord, a 0.6 mm thick rubber sheet, a cord, and a 0.6 mm thick rubber sheet were sequentially stacked to prepare a sample, which was then subjected to a 60 kg / cm 2 The vulcanized samples were vulcanized at 170°C for 15 minutes under a pressure of 1.5 g. Next, the vulcanized samples were cut to prepare test specimens with a width of 1 inch. The samples thus prepared were subjected to a peeling test at a rate of 125 mm / min at 25°C using a universal testing machine (Instron Co., Ltd.), and then the adhesion strength of the tire cord on the carcass layer was measured. At this time, the average value of the load generated at the time of peeling was calculated from the adhesion strength.

[0144] [Table 2]

[0145]

[0146] According to Table 2, it can be confirmed that when the tire cords according to the Examples of the present invention are used, they have excellent adhesion to rubber, compared with the tire cords of the Comparative Examples.

Claims

1. A tire cord, comprising: A fiber base woven with warp yarns and weft yarns of at least one of nylon, rayon, aramid, and polyester including PET having a fineness of 600 to 750 de, with a warp density of 90% or more and a weft density of 3% to 25% and a number of warp yarns per unit length (n / inch) of 58 or more and a number of weft yarns per unit length (n / inch) of 5 to 30; an adhesive layer formed on the fiber substrate; and a rubber coating layer formed on the adhesive layer, Wherein, the rubber coating comprises synthetic rubber or natural rubber, The coating amount of the rubber coating layer per unit area of ​​the adhesive layer is 75 g / m 2 Up to 300g / m 2 , Wherein, the thickness of the rubber coating is 0.04mm to 0.10mm, and The tire cord has a breaking strength of 10.0 g / d to 15.0 g / d and an elongation at break of 23.55% to 30% measured according to the standard test method of ASTM D885, and when the bonding strength is evaluated according to the standard test method of ASTM D4393, the bonding strength of the tire cord is above 18.2 kgf.

2. The tire cord according to claim 1, wherein: The fiber base has a thickness of 0.10 mm to 0.60 mm.

3. The tire cord according to claim 1, wherein: The rubber coating layer is formed by applying a rubber coating solution including 10 to 30 wt % of an elastomeric polymer composition including synthetic rubber or natural rubber and 70 to 90 wt % of a solvent onto the adhesive layer.

4. The tire cord according to claim 1, wherein: The adhesive layer includes resorcinol-formaldehyde-latex (RFL).

5. A method for manufacturing a tire cord, comprising the following steps: Prepare a fiber substrate woven with warp yarns and weft yarns of at least one of nylon, rayon, aramid, and polyester including PET having a fineness of 600 to 750 de, with a warp density of 90% or more and a weft density of 3% to 25% and a number of warps per unit length (n / inch) of 58 or more and a number of wefts per unit length (n / inch) of 5 to 30; forming an adhesive layer on the fiber substrate; and coating the adhesive layer with a rubber coating solution and performing a heat treatment to form a rubber coating layer, Wherein, the rubber coating comprises synthetic rubber or natural rubber, The coating amount of the rubber coating layer per unit area of ​​the adhesive layer is 75 g / m 2 Up to 300g / m 2 , Wherein, the thickness of the rubber coating is 0.04mm to 0.10mm, and The tire cord has a breaking strength of 10.0 g / d to 15.0 g / d and an elongation at break of 23.55% to 30% measured according to the standard test method of ASTM D885, and when the bonding strength is evaluated according to the standard test method of ASTM D4393, the bonding strength of the tire cord is above 18.2 kgf.

6. The method for manufacturing a tire cord according to claim 5, wherein: The fiber base has a thickness of 0.10 mm to 0.60 mm.

7. The method for manufacturing a tire cord according to claim 5, wherein: The rubber coating solution includes 10 to 30 wt % of an elastomeric polymer composition including synthetic rubber or natural rubber; and 70 to 90 wt % of a solvent.

8. The method for manufacturing a tire cord according to claim 5, wherein: The adhesive layer includes resorcinol-formaldehyde-latex (RFL).

9. The method for manufacturing a tire cord according to claim 5, The method further includes the step of twisting the warp yarns including at least one of nylon, rayon, aramid, and polyester including PET.

10. A tire comprising the tire cord according to any one of claims 1 to 4.

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