KR20220168279A - Eco-friendly high performance radial tire including cap ply applied with cellulose artificial fiber-polyester hybrid cord - Google Patents

Abstract

The present invention relates to eco-friendly, high-performance radial tires with reduced fuel consumption. The present invention improves noise reduction, high-speed durability, and steering stability with improved fuel efficiency due to reduced tire deformation during driving and improved tire molding and vulcanization processes and manufacturing of eco-friendly cap plies. More specifically, by replacing para-aramid and polyamide 66, which make up the existing aramid-polyamide 66 hybrid cord for cap ply, with eco-friendly materials, the Environment, Society, Governance (ESG) competitiveness has been recently improved by using non-petroleum-based or recycled materials, and the characteristics of existing high-performance materials have been secured at 50-100% level. Thus, the performance of a tire also shows similar characteristics as when high-performance materials are used. That is, when using existing eco-friendly materials, the performance and cost disadvantages which may arise compared to using existing petroleum-based materials are minimized.

Description

Eco-friendly high performance radial tire including cap ply applied with cellulose artificial fiber-polyester hybrid cord}

The present invention relates to a fuel economy eco-friendly radial tire that improves noise, high-speed durability, and steering stability, improves fuel efficiency due to reduced tire deformation during driving, manufactures cap plies made of eco-friendly materials, and improves tire molding and curing processes. .

The aramid hybrid cord, which has been used as a cap ply for high-performance tires so far, has been applied with only the initial modulus/cutting modulus ratio as a characteristic. Previous patents related to aramid hybrids include Sumitomo Rubber's Japanese Patent Publication No. 1989-247204 and Michelin's US Patent No. 7,222,481.

1 is a graph showing the stress strain of a conventional aramid hybrid cord.

1 shows the slope of the initial modulus and final modulus of the aramid hybrid cord.

In Japanese Patent Laid-Open No. 1989-247204 of Sumitomo Rubber, which was previously filed, the ratio between initial modulus and final modulus is limited to 2 to 9. On the other hand, Michelin's patent defines the ratio of initial modulus and final modulus of 10 or more.

Michelin's patent differs from Sumitomo's in the range of modulus ratio of aramid hybrid cord. What these two patents have in common is that the ratio of modulus defines only two initial modulus and final modulus. In addition, Michelin's patent, for example, has an ambiguous aspect in which the definition of initial modulus is not clear. Theoretically, the initial modulus is defined as the slope of the tangent to the stress-strain curve at zero strain. However, when the tangent line is drawn at the zero point in the measurement graph of the actual tire cord, a very low slope occurs. In order to prevent this, it is necessary to set a specific section and obtain a tangent (tan α) slope value, but the section for this is not mentioned in the above document. In fact, it is not clear whether the slope of the tangent line at the actual strain 0 can accurately represent the initial modulus value at 0.5 cN/tex or 0.05 g/d, which is a preload condition during a general tensile test. In the existing super-load condition ~ micro-displacement section, stress is not evenly distributed due to the structural characteristics of the fiber bundles that make up the cord (lack of convergence under a certain load), and structural deformation that improves the convergence of the filament occurs, resulting in tensile stress. It seems that there are many insufficient parts to define the initial modulus of the material in the pre-load condition during the test. Due to this phenomenon, the modulus in the initial microsection has a lower value than the originally desired characteristic value. In fact, after applying an initial load of 0.05 g/d with only aramid cord and then performing a tensile test, if the slope of the tangent at the origin, that is, the initial modulus is obtained from a small section at the origin, the ratio with the final modulus is 1 in some cases: There are also unwanted results that can be 10 degrees.

In order to solve this error, in this patent, a tensile test is performed by applying an initial load twice as large as the previous one, and at this time, the initial modulus is defined as a tangent at a strain of 0, and the initial load at this time is specified as 0.10 g/d. to coza Thus, instead of the low initial modulus of the micro-strain section that can occur due to the difference in the focusing force of the fiber bundles constituting the cord, it can be regarded as the initial modulus that can represent the overall material characteristics.

Looking at this, it is true that the focus was only on tire performance according to the characteristics of the material, but the material approach to securing sustainability was insufficient.

Chemical formulas 1 and 2 show chemical reaction formulas of the polymerization process of para-aramid and polyamide 66, respectively.

The monomers used here are all petroleum-based, and are far from bio-derived or recycled materials, which are currently referred to as eco-friendly materials, and it is a reality that recycling is not easy after being used in tires.

In order to meet the future carbon-neutral target date of 2045, it is important to increase the energy efficiency of vehicles and reduce the rolling resistance of tires, but it is also very important whether the materials constituting the tires are environmentally friendly or recyclable. has become

In particular, among the materials used in tires, in a situation where tire cords are difficult to access as eco-friendly materials, it is very important to discover a fiber cord that satisfies eco-friendly material titles. In this patent, the existing high-performance tires We want to devise a plan that can minimize the cost increase while approaching the aramid-polyamide 66 hybrid cord in an eco-friendly way, which was used as a capply in the .

An object of the present invention is to replace para-aramid and polyamide 66 constituting the existing aramid-polyamide 66 hybrid cord for cap ply with eco-friendly materials, and to use ESG (Environment, Society, By improving competitiveness in terms of governance and securing 50 to 100% of the characteristics of existing high-performance materials, the performance of tires should show similar characteristics to those of using high-performance materials. In other words, when using existing eco-friendly materials, the purpose is to minimize the parts that may cause disadvantages in terms of performance and cost compared to using existing petroleum-based materials.

A hybrid cord for a tire according to an embodiment of the present invention is characterized by ply-twisting cellulose artificial fibers and polyester fibers.

The cellulose artificial fibers may be at least one selected from viscose rayon, regenerated cellulose fibers using carbon disulfide, lyocell, tencel, and cellulose artificial fibers made from pulp.

The polyester may be at least one selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and polyethylene furanoate (PEF). .

The polyester fiber may be bio-derived polyester.

The polyester fiber may be PET prepared by reacting biomass ethylene glycol and terephthalic acid.

The polyester fiber may be polyethylene furanoate (PEF) prepared by reacting 2,5-FuranDiCarboxylic Acid (FDCA) with ethylene glycol.

The polyester fiber may be polyethylene furanoate (PEF) prepared by reacting biomass ethylene glycol and 2,5-FuranDiCarboxylic Acid (FDCA).

The quantitative fineness of the hybrid cord may be greater than 1,000 denier and less than 5,000 denier.

The hybrid cord may have a twist coefficient of 100 or more and 250 or less based on the twist coefficient of Equation 1 below.

<식 1>

<Equation 1>

Here, α _d is the twist coefficient based on denier, T is TPM (Twist per meter), and ρ _d is the quantitative fineness in denier units of the hybrid cord.

The hybrid cord may have a ratio of cellulose artificial fiber and polyester of 1:5 to 5:1.

A method for manufacturing a hybrid cord for a tire according to an embodiment of the present invention includes ply-twisting cellulose artificial fibers and polyester-based thermoplastic fibers.

An eco-friendly, high-performance radial tire according to an embodiment of the present invention is characterized in that a hybrid cord obtained by ply-twisting cellulose artificial fibers and polyester fibers is applied to the cap ply.

The hybrid cords may have an interval between cords of 0.1 mm to 0.25 mm.

An orientation angle on the circumference of the tire of the cap ply to which the cellulose artificial fiber-polyester hybrid cord is applied may be applied in the range of -7 degrees to +7 degrees.

The angle of the steel belt layer of the tire to which the cellulose artificial fiber-polyester hybrid cord is applied to the cap ply may be 24 degrees to 30 degrees.

The elastic modulus ratio for each section of the cellulose artificial fiber-polyester hybrid cord may satisfy Equation 2 below.

<식 2>

<Equation 2>

here ,

△(2% - 0%): slope of 0 to 2% on the load-tensile (strain) curve

△(8% - 7%): 7-8% slope on the load-tensile (strain) curve

The cellulosic man-made fiber-polyester hybrid cord may have a break elongation range of 8% to 12% in the state of the dip cord.

A method for manufacturing a hybrid cord for a tire according to an embodiment of the present invention includes ply-twisting cellulose artificial fibers and polyester-based thermoplastic fibers.

The eco-friendly, high-performance radial tire to which the hybrid cord according to the present invention is applied to the cap ply improves high-speed durability and steering stability, reduces noise, and improves fuel efficiency by reducing tire deformation during driving. In addition, by improving the vulcanization process and using natural materials, it is environmentally friendly and provides an effect of minimizing cost increase. In addition, by securing a level of 50 to 100% compared to the characteristic level of existing petroleum-based high-performance materials, it provides an effect of resolving disadvantages in performance and cost compared to using existing materials.

1 is a graph showing the stress strain of a conventional aramid hybrid cord.
2 is a schematic cross-sectional view of a radial tire to which a hybrid cord according to an embodiment of the present invention is applied.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, it may be implemented in many different forms and is not limited to the embodiments described herein.

The present invention maintains the properties of an aramid-polyamide 66 hybrid cord, which is a cord for cap ply of existing high-performance radial tires, while using non-oil-based materials or plied cellulose artificial fibers and polyester fibers to reduce costs. It is a technology related to a hybrid cord, a manufacturing method thereof, and an eco-friendly radial tire using the hybrid cord.

The hybrid cord in which cellulose artificial fibers and polyester fibers are plied according to the present invention replaces the existing thermostable aramid with cellulose artificial fibers and polyamide 66 with polyester to obtain cellulose artificial fibers, which are eco-friendly materials. By using it, it is possible to increase the amount of eco-friendly materials used in tire manufacturing, and to provide advantages of relatively low cost compared to aramid. In addition, when polyamide 66 fiber, which reduces competitiveness in tire manufacturing cost due to limited suppliers, is replaced with polyester, it is possible to reduce cost by 50 to 90% compared to existing polyamide 66 raw material prices. Competitiveness can also be secured from the side.

Currently, non-petroleum-based fiber materials that have commercial competitiveness include fibers obtained by regenerating or dissolving cellulose, such as Viscose Rayon, Tencel, and Lyocell. Since these fibers use cellulose, which exists inexhaustibly in the natural world, they have the advantage of being able to secure raw materials forever as long as plants exist. Compared to conventional petroleum-based synthetic polymer materials, there is a disadvantage that energy and cost consumed in cellulose processing can be relatively high, but it has a great advantage in that it has thermal stability characteristics like aramid. It has been 100 years since the first regenerated cellulosic fibers appeared on the market, but in a larger context the first Viscose Rayon has not yet given way to synthetic polymer fiber materials, and Lyocell, Tencel and others developed at the end of the 20th century. Eco-friendly cellulosic artificial fibers using the same NMMO (N-Methylmorpholine N-Oxide) as a solvent have also been developed and are emerging in the textile material market. In particular, unlike Viscose Rayon, Lyocell and Tencel use NMMO, a heterocyclic amine oxide that is harmless to the human body, as a solvent, so carbon disulfide (CS ₂ ) is not used at all, and thus eco-friendly characteristics appear in the fiberization process. In addition, since many of the recent Rayon manufacturing processes are developing and applying advanced processes in which sealing and solvent recovery are 100% in all processes, it is somewhat difficult to argue that Viscos Rayon has environmental hazards recently.

When the cellulose artificial fiber as described above is applied to the fiber cord of a pneumatic radial tire, some of the physical properties of Para-Aramid, which is used at a high price due to its excellent thermal and mechanical properties due to the thermal stability of the cellulose artificial fiber can be expected to be reproducible. Due to the nature of the material, Para-Aramid has a Young's Modulus of 500 g/d or higher and a strength (strength at break) of 20 g/d or higher, whereas Super Grade viscos Rayon, used for tire cord among Viscos Rayon, has 5 g/d or higher strength. Since it has strength (breaking strength) of d level, when using the same amount as Para Aramid, it lacks reinforcing performance as Cap Ply, so there is a disadvantage that the amount of use must be increased. In particular, since increasing the EPI (End per Inch, the number of cord strands per inch width) may have problems maintaining appropriate cord spacing and the range is very limited, a method of increasing the quantitative fineness of the cord may be desirable, which eventually By increasing the thickness of the cap ply layer, the weight of the tire is increased. Nevertheless, it seems that the much lower cost and advantages as an eco-friendly material compared to aramid make up for the above disadvantages.

The polyester, which replaces polyamide 66, can be introduced as an eco-friendly material in various ways. As one of these methods, it is possible to recycle commercially available PET (Polyethylene terephthalate) bottles by collecting/washing them and then re-melting and spinning them, or they can also be manufactured into PET chips through depolymerization. As an introduction method to other eco-friendly materials, ethylene glycol (EG) among the monomers used for polymerization of PET may be prepared based on biomass and used for polymerization. As a method of obtaining ethylene glycol from biomass, a method of obtaining ethanol by fermenting corn and further oxidizing it to obtain ethylene glycol is the most widely used method.

In addition, if PEF (Polyehtylene furanoate, IUPAC name: Polyethylene 2,5-furanodicarboxylate) is used instead of PET, it is possible to use bio-derived polyester material that is close to 100%. PEF is produced by replacing the terephthalate monomer of conventional general-purpose PET with 2,5-FuranDiCarboxylic Acid (FDCA). It is also a bio-derived monomer that can be obtained. That is, when PEF is obtained by condensation polymerization of biomass ethylene glycol and FDCA, 100% natural (Bio Derived) polyester is obtained.

The polyesters obtained in this way can be fibrous, and an eco-friendly high modulus cap ply can be manufactured by ply-twisting with cellulose artificial fibers. The cellulose artificial fibers and polyester fibers are manufactured into ply-twisted yarns through a Direct Cabler, 2 for 1 Cabler, or Ring Twister.

The reason why polyester is used instead of only cellulose artificial fibers is that tensile strain of at least 2 to 5% in the circumferential direction of the tread inevitably occurs during the curing process during the tire manufacturing process. This is to facilitate heat setting during cooling after tensile deformation when heat and tensile force are applied during the curing process. In the vulcanization process, the tire is inflated and adhered to the mold, and the cap ply wound in the circumferential direction should be attached with a pure tension of 2 to 5%. When applied to the ply, not only the resistance is high when deformation occurs, but also the force to return to the original length when cooled after completion of the vulcanization process is large, resulting in tire defects.

The cellulose artificial fiber may be any one of biscos Rayon, Liocell, and Tencel, and the polyester may be polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT). ), and polyethylene furanoate (PEF).

The ply-twisted cellulosic man-made fiber-polyester hybrid cord preferably has a ratio of cellulose to polyester in the range of 1:5 to 5:1. If the ratio of cellulose artificial fibers is less than 1:5, thermal stability may not be sufficiently expressed, and if it exceeds 5:1, thermal stability is too strong, resulting in tensile properties related to manufacturability. Stress value in the low elongation range of 1 to 4% There may be downsides to this increase.

The quantitative fineness of the cellulose artificial fiber-polyester hybrid cord is preferably 1,000 denier or more and 5,000 denier or less. If the denier is less than 1,000 denier, there is a possibility that the cap ply may be cut during high-speed driving due to lack of reinforcing properties. has a downside.

The cellulose artificial fiber-polyester hybrid cord preferably has a twist coefficient in the range of 100 to 250.

If the twist coefficient α _d of Equation 1 below is less than 100, the strength and processability may be reduced due to the lack of cord cohesive force. It cannot be applied to tires.

<식 1>

<Equation 1>

Here, α _d is the twist coefficient based on denier, T is TPM (Twist per meter), and ρ _d is the quantitative fineness in denier units of the hybrid cord.

The ply-twisted yarn obtained by the above method obtains a dip fabric through heat treatment after weaving. At this time, in the heat treatment process, after immersing and drying the code in RFL (Resorcinol Formaldehyde Latex) to improve the shape stability of the code, heat setting, and adhesion with the skim compound, the RFL is crosslinked through a chemical reaction. . Here, RFL is a composition of Resorcinol Formaldehyde and Latex. Resorcinol Formaldehyde plays a role in bonding with fibers, and Latex plays a role in causing a compound and vulcanization reaction, respectively. Recently, due to the environmental hazard issue of formaldehyde, some researches on dipping recipes that exclude formaldehyde, and there are tire cord manufacturers and tire manufacturers who are starting to actually apply this.

The obtained dip fabric can be put into a rolling process, topped with a skim compound, and then subjected to a slitting (cutting) process, and then applied as a tire cap ply. Alternatively, after ply-twisting, the single end dip cord obtained through heat treatment of the single end cord is manufactured in a strip form through an extrusion process, and then wound in the circumferential direction on the steel belt layer in the forming process to form a cap ply. there is.

Here, the hybrid cord rolled product or hybrid cap ply semi-finished product may be wound in a range of -7 degrees to +7 degrees relative to the circumferential direction, and the width of the cap ply semi-finished product is preferably 4 mm to 25 mm. If it is less than 4 mm, the efficiency is lowered in the semi-finished product preparation process, and the time required for the capply winding process during the molding process is also reduced, resulting in a decrease in productivity. If the cap ply width exceeds 25 mm, the angle of the cap ply may be skewed more than -7 degrees or +7 degrees compared to the circumferential direction of the tire, so Conicity (wheel section slope) among the uniformity of the tire may be disadvantageous. In terms of PRAT (Plysteer residual Algning Torque), there is a disadvantage that the directionality may vary greatly depending on the winding direction.

In the hybrid cord rolled product or cap ply semi-finished product, the rubber thickness from the cord surface to the skim compound surface is preferably in the range of 0.10 mm to 2.0 mm. If it is less than 0.1 mm, the distance between the adjacent compound or other adjacent cords (carcass cord, belt cord) and the hybrid cord becomes narrow, resulting in increased stress concentration or change in stress, resulting in unfavorable driving durability, and exceeding 2.0 mm In this case, more than necessary skim compound is used, which is disadvantageous in terms of tire weight.

In addition, the interval between the hybrid cords is preferably in the range of 0.13 mm to 0.25 mm. If the interval between hybrid cords is 0.13 mm or less, cracks propagate easily and driving durability is unfavorable, and if it is 0.25 mm or more, reinforcing properties may be insufficient because the cords cannot be used sufficiently.

The cellulosic artificial fiber-polyester hybrid cord preferably has a breaking elongation of 8% to 12% in the state of the dip cord containing the adhesive. may occur, and if it exceeds 12%, it is difficult to sufficiently express the thermal stability of the cellulose artificial fiber.

The elastic modulus ratio of the cellulose artificial fiber-polyester hybrid cord preferably satisfies the condition of Equation 2 below. If the elastic modulus ratio is less than 0.5, two things can be considered. First, if the elastic modulus in the range of 0 to 2% is high, it is difficult to manufacture smoothly in the vulcanization process during manufacturing (circumferential expansion of 2% or more proceeds smoothly) Second, if the modulus of elasticity in the 7 to 8% section is low, the main purpose is to suppress the growth of the circumference due to centrifugal force during driving and to increase the in-plane stiffness of the tread. There are disadvantages that may cause a lack of roles.

<식 2>

<Equation 2>

here ,

△(2% - 0%): slope of 0 to 2% on the load-tensile (strain) curve

△(8% - 7%): 7-8% slope on the load-tensile (strain) curve

The cellulose artificial fiber-polyester hybrid cord should be manufactured to have a tensile strength of at least 14 kgf or more based on 1 end. If it has a lower strength than this, there is a risk of an accident in which the cap ply cord is cut due to centrifugal force during high-speed driving.

When the cellulose artificial fiber-polyester hybrid cord of the present invention is applied to a radial pneumatic tire, the angle of the steel belt layer is important. In particular, when the belt angle is formed at 31 degrees or more to improve high-speed durability, the tensile force to be shared by the reinforcing belt increases, and as a result, the strength is lower than that of the hybrid cord containing aramid Cellulosic artificial fiber-polyester hybrid cord During use, an accident in which the capply cord is cut may occur. For this reason, when using the cellulose artificial fiber-polyester hybrid cord of the present invention, the steel belt angle of the radial pneumatic tire to be applied is preferably applied in the range of 24 degrees to 30 degrees. When the steel belt angle is less than 24 degrees, the reason for using the cellulose artificial fiber-polyester hybrid cord is reduced because the tensile force sharing rate due to the centrifugal force applied by the steel belt increases, and when the steel belt angle exceeds 30 degrees Since the change in the stress value applied to the end of the steel belt cord becomes larger, the durability of high-speed running is unfavorable.

2 is a schematic cross-sectional view of a radial tire to which a hybrid cord according to an embodiment of the present invention is applied.

Referring to FIG. 2 , the tire includes a tread part 1, a sidewall part 2, and a bead part 3. A carcass layer 4 is constructed between the pair of left and right bead parts 3, and both ends of the carcass layer 4 in the tire width direction move from the inside of the tire to the outside around the bead part 5, respectively. wind up A steel belt layer 5 and a belt layer 6 are installed on the outside of the carcass layer 4, and an inner liner (not shown) is disposed on the inside of the carcass layer 4. The hybrid cord according to an embodiment of the present invention may be applied to the belt layer 6, and specifically to the cap ply.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

[ Manufacture Example: Manufacture of Hybrid Cord ]

Comparative Example 1 applied Nylon66 840D/2 27EPI as Cap Ply, Comparative Example 2 applied A1500D/1 + N66 1260D/1 27EPI, and Comparative Example 3 applied A1500D/2 + N66 1260D/1.

In Example 1 according to an embodiment of the present invention, Rayon 1650D/2+PET 1000D/1 and Example 2 applied Lyocell 1100D/2+P1000D/1.

Table 1 below shows the structure and physical properties of each code and the results derived from the indoor driving test and the actual vehicle performance test of the tire (225/45R17) manufactured using the code.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 structure Polyamide 66 840D/2 27EPI Aramid 1500D/1+
N66 1260D/1 27 EPI Aramid 1500D/2+ Polyamide 66 1260D/1
20EPI Rayon 1650D/2+
PET 1000D/1
30 EPIs Lyocell 1100/2+
PET 1000D/1
30 EPIs Lyocell 1100D/2 + PEF 1000D/1 30EPI30EPI Topping Gauge 1.0mm 1.1mm 1.2mm 1.2mm 1.2mm 1.2mm Cord1 strand
strong 14.5 kgf 34 kgf 58 kgf 19 kgf 17 kgf 17.5 kgf Strong/inch (1 Strand Strong X EPI) 391kgf/inch 918 kgf/inch 1,160 kgf/inch 570kgf/inch 510kgf/inch 525kgf/inch LASE (2%) 1.2 kgf 3.8 kgf 4.5 kgf 3 kgf 2.9 kgf 3.0kg LASE (2%)/inch 32.4 kgf/inch 54 kgf/inch 90 kgf/inch 90 kgf/inch 88 kgf/inch 90 kgf/inch LASE (5%) 3.1 kgf 15 kgf 26 kgf 10 kgf 9 kgf 9.4 kgf LASE(5%)/inch 83.7 kgf/inch 405 kgf/inch 520 kgf/inch 300 kgf/inch 270 kgf/inch 282kgf/inch standard 245/40R18Y ← ← ← ← ← application area Cap Ply (1 Ply) ← ← ← ← ← weight 11.4kg 11.45 11.5 11.5 11.5 ← Belt Angle 29 degrees 29 degrees 29 degrees 29 degrees 29 degrees ← Dynamic profile (circumferential growth while driving)
(diameter increase during 300 kph) 20mm 10mm 7mm 10mm 12mm 11.5mm rolling resistance 100 99 99 99 99 99 High-speed driving durability
(ECE R30) 1:45 1:55 1:59 1:53 1:51 1:52 steering safety 100 110 112 109 109 109 ride comfort 100 99 98 99 99 99 noise 100 101 102 101 100 100 Cap Ply cost (based on rolling stock) (index) 100 200 230 140 135 180

※ An index of 100 or more is superior to Comparative Example 1, and below is inferior to Comparative Example 1. However, the lower the index, the better the rolling resistance.

Uniformity is an index value that combines values of R1H, conicity, etc. measured through a uniformity measuring instrument, and the higher the value is, the higher the value is, based on Comparative Example 1. For the rolling resistance, equipment owned by Hankook Tire was used, and the RRc value of Comparative Example 1 was expressed as an index based on 100, and the higher the index value, the better the rolling resistance. The high-speed driving durability was conducted by increasing the speed by 20 km/h to 30 km/h every 10 minutes after the start of driving on a drum-type driving endurance tester. For the dynamic profile, the growth of the circumference by the centrifugal force according to the driving speed was measured using a dedicated test facility to measure and record the profile change for each position of the tread part on the shoulder. The smaller the profile change, the better the performance. In Table 1, Comparative Example 1 was expressed as an index of 100, and the higher the index than 100, the better the Comparative Example 1, but the lower the rolling resistance, the better. In addition, steering stability, ride comfort, and noise are indexes evaluated by the test driver through actual vehicle driving.

In the case of Comparative Example 1 using N66 840D/2 27EPI, it can be confirmed that the noise and ride comfort are excellent, but the high-speed driving durability and steering stability are inferior to those of Comparative Examples 2 and 3 and Examples.

In the case of Comparative Examples 2 and 3, it can be confirmed that the high-speed driving durability and steering stability are superior to those of Comparative Example 1, but the weight is slightly increased. This is a part that can appear as a disadvantage of rolling resistance. When calculating only the cost of the cap ply used in terms of cost cost, it can be seen that Comparative Examples 2 and 3 cost about twice as much as Comparative Example 1. Nevertheless, the reason why aramid-nylon hybrids are used is that high-speed driving durability, stability, and steering stability are dramatically changed.

Examples 1 and 2 are for tires made of capply in which cellulose-based artificial fibers and PET are ply-twisted. Since the strength is lower than that of aramid, the EPI was slightly increased, and cellulose-based artificial fibers and PET, a thermoplastic material, were used. A three-ply structure of :1 was applied.

In Examples 1 and 2, it can be seen that the steering stability and high-speed endurance driving performance are improved compared to Comparative Example 1 in which the existing N66 840D/2 27PI is applied as 1 Ply. On the other hand, although it is slightly lower than the existing aramid-nylon hybrid, there is a big difference from Comparative Example 1 using only the existing nylon as a cap ply, and in terms of cost, it can be applied at a lower cost than the existing aramid-nylon hybrid cap ply semi-finished product. There are advantages.

Example 3 is a case in which a cap ply is made of 100% natural origin material, and since the tensile modulus of PEF is higher than that of PET, it has a higher slope in terms of load-tensile characteristics. Since PEF is not yet widely commercialized like general-purpose polymer materials, it tends to be disadvantageous compared to biomass PET in terms of price.

In addition, although it is difficult to calculate quantitatively, it is judged to be a desirable direction in terms of sustainability of raw materials/materials by applying a certain portion of the percentage of textile cords used in tires as non-petroleum-based.

1: tread part
2: sidewall part
3: bead part
4: steel belt layer
5: belt layer

Claims (16)

A hybrid cord for a tire, characterized in that it is a plied yarn of cellulose artificial fiber and polyester fiber. According to claim 1,
The cellulose artificial fiber is a hybrid cord for a tire, characterized in that at least one selected from viscose rayon, regenerated cellulose fiber using carbon disulfide, lyocell, tencel and cellulose artificial fiber manufactured from pulp. According to claim 1,
The polyester fiber is at least one selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) and polyethylene furanoate (PEF). Hybrid cord for tire characterized by. According to claim 1,
The polyester fiber is a hybrid cord for a tire, characterized in that bio-derived polyester. According to claim 1,
The polyester fiber is a hybrid cord for a tire, characterized in that PET produced by reacting biomass ethylene glycol and terephthalic acid. According to claim 1,
The polyester fiber is a hybrid cord for a tire, characterized in that Polyethylene Furanoate (PEF) prepared by reacting 2,5-FuranDiCarboxylic Acid (FDCA) and ethylene glycol. According to claim 1,
The polyester fiber is a hybrid cord for a tire, characterized in that polyethylene furanoate (PEF) prepared by reacting biomass ethylene glycol and 2,5-FuranDiCarboxylic Acid (FDCA). According to claim 1,
The hybrid cord for a tire, characterized in that the quantitative fineness of the hybrid cord for a tire is greater than 1,000 denier and less than 5,000 denier. According to claim 1,
The hybrid cord for a tire is characterized in that the twist coefficient of the hybrid cord for a tire is 100 to 250 based on the twist coefficient of Equation 1 below.

<Equation 1>
In Equation 1, α _d is the twist coefficient based on denier, T is TPM (Twist per meter), and ρ _d is the quantitative fineness in denier units of the hybrid cord. According to claim 1,
The hybrid cord for a tire is a hybrid cord for a tire, characterized in that the ratio of cellulose artificial fiber and polyester is 1: 5 to 5: 1. A tire characterized in that the tire hybrid cord according to claim 1 is applied to the cap ply. According to claim 11,
The hybrid cord for the tire is a tire, characterized in that the interval between the cords is 0.1 mm to 0.25 mm. According to claim 11,
The tire, characterized in that the orientation angle of the cap ply on the tire circumference ranges from -7 degrees to +7 degrees. According to claim 11,
The tire, characterized in that the angle of the steel belt layer applied to the tire is 24 degrees to 35 degrees. According to claim 11,
A tire characterized in that the elastic modulus ratio for each section of the hybrid cord for the tire satisfies Equation 2 below.

<Equation 2>
In Equation 2,
△(2% - 0%): slope of 0 to 2% on the load-tensile (strain) curve
△(8% - 7%): 7-8% slope on the load-tensile (strain) curve According to claim 11,
A tire, characterized in that in the state of the dip cord of the hybrid cord for the tire, the break elongation range is 8% to 12%.

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