KR102578622B1 - 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 a fuel-efficient, eco-friendly, high-performance radial tire that improves noise, high-speed durability, and steering stability, improves fuel efficiency due to reduced tire deformation while driving, manufactures cap plies made of eco-friendly materials, and improves tire molding and curing processes. . More specifically, by replacing para-aramid and polyamide 66, which make up the existing aramid-polyamide 66 hybrid cord for cap plies, with eco-friendly materials, ESG (Environment, Society, Governance) has recently been introduced to use non-petroleum-based or recycled materials. ) As competitiveness is improved and the characteristics of existing high-performance materials are secured at a level of 50 to 100%, the goal is to ensure that the performance of tires exhibits similar characteristics to those when high-performance materials are used. In other words, the purpose is to minimize the performance and cost disadvantages that may arise when using existing eco-friendly materials compared to using existing petroleum-based materials.

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-efficient eco-friendly radial tire that improves noise, high-speed durability, and steering stability, improves fuel efficiency due to reduced tire deformation while driving, manufactures cap plies made of eco-friendly materials, and improves tire molding and curing processes. .

Until now, the aramid hybrid cord used as a cap ply in high-performance tires has been applied with only the initial modulus/modulus ratio at cutting as its characteristic. Previous patents related to aramid hybrid include Sumitomo Rubber's Japanese Patent Publication No. 1989-247204 and Michelin's U.S. Patent No. 7,222,481.

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

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

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

Michelin's patent differs from Sumitomo's patent in the range of the modulus ratio of the aramid hybrid cord. What these two patents have in common is that only two modulus ratios are defined: the initial modulus and the final modulus. Additionally, taking Michelin's patent as an example, there is an ambiguous aspect in which the definition of the initial modulus is not clear. In theory, the initial modulus is defined as the slope of the tangent line on the stress-strain curve when the strain is zero. However, if a tangent line is drawn at point 0 on the actual tire cord measurement graph, a very low slope occurs. To prevent this, a specific section must be set and the tangent (tan α) slope value must be obtained, but the section for this is not mentioned in the above document. In fact, in general tensile testing at an initial load condition of 0.5 cN/tex or 0.05 g/d, it is not clear whether the slope of the tangent line at a strain rate of 0 can accurately represent the initial modulus value. In the existing ultra-load condition ~ micro-displacement section, due to the structural characteristics of the fiber bundles that make up the cord (lack of focusing force below a certain load), stress is not distributed evenly and structural deformation occurs that improves the focusing force of the filament, resulting in tensile tension. It appears that there are many shortcomings in defining the initial modulus of the material under the initial load condition during the test. Due to this phenomenon, the modulus in the initial small section appears to have a lower value than the original desired characteristic value. In fact, if an initial load of 0.05 g/d is applied using only an aramid cord and a tensile test is performed, then the slope of the tangent at the origin, that is, the initial modulus, is obtained in a small section at the origin, the ratio with the final modulus is sometimes 1: Unwanted results, which can be as high as 10, may appear.

To solve this error, this patent attempts to conduct a tensile test by applying an initial load twice that of the existing one and define the initial modulus as a tangent at a strain rate of 0, and the initial load at this time is specified as 0.10 g/d. Let's do it. As a result, instead of the low initial modulus in the micro-strain section that may occur due to differences in the focusing power of the fiber bundles that make up the cord, it can be viewed as an initial modulus that can represent the overall material characteristics.

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

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

The monomers used here are all petroleum-based and are quite far from bio-derived or recycled materials, which are currently called eco-friendly materials, and the reality is that they are not easy to recycle after being used in tires.

In order to meet the future carbon neutrality target of 2045, it is important to increase the energy efficiency of vehicles and reduce rolling resistance of tires, but it is also very important whether the materials that make up tires are environmentally friendly or recyclable. It became.

In particular, among the materials used in tires, tire cord is an eco-friendly material that is difficult to access, so it is very important to discover a fiber cord that satisfies eco-friendly material ties, and in this patent, existing high-performance tires We would like to devise a way to minimize cost increases while approaching the aramid-polyamide 66 hybrid cord, which was used as a cap ply, in an environmentally friendly manner.

The purpose of the present invention is to replace para-aramid and polyamide 66, which constitute the existing aramid-polyamide 66 hybrid cord for cap ply, with eco-friendly materials, thereby creating an environment, society, and environment (ESG) system that allows the use of non-petroleum-based or recycled materials. As competitiveness in terms of governance is improved and the characteristics of existing high-performance materials are secured at a level of 50 to 100%, the performance of tires is also designed to exhibit characteristics similar to those when high-performance materials are used. In other words, the purpose is to minimize the performance and cost disadvantages that may arise when using existing eco-friendly materials compared to using existing petroleum-based materials.

The hybrid cord for tires according to an embodiment of the present invention is characterized by twisting cellulose artificial fibers and polyester fibers.

The cellulose artificial fiber may be one or more selected from viscose rayon, regenerated cellulose fiber using carbon disulfide, lyocell, tencel, and cellulose artificial fiber manufactured from pulp.

The polyester may be one or more 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 manufactured by reacting biomass ethylene glycol and terephthalic acid.

The polyester fiber may be Polyethylene Furanoate (PEF) produced by reacting 2,5-FuranDiCarboxylic Acid (FDCA) and ethylene glycol.

The polyester fiber may be Polyethylene Furanoate (PEF) produced by reacting biomass ethylene glycol with 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 of manufacturing a hybrid cord for tires according to an embodiment of the present invention includes the step of 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 by applying a hybrid cord made of cellulose artificial fiber and polyester fiber to the cap ply.

The hybrid cord may have an inter-cord spacing of 0.1 mm to 0.25 mm.

The orientation angle of the cap ply using the cellulose artificial fiber-polyester hybrid cord on the tire circumference may range from -7 degrees to +7 degrees.

The angle of the steel belt layer of a tire to which the cellulose artificial fiber-polyester hybrid cord is applied to the cap ply may be 24 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 between 0 and 2% on the force-tensile (strain) curve

△(8% - 7%): Slope of 7~8% section on the force-tensile (strain) curve

The break elongation range of the cellulose artificial fiber-polyester hybrid cord in the dip cord state may be 8% to 12%.

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

The eco-friendly, high-performance radial tire with the hybrid cord according to the present invention applied to the cap ply improves high-speed durability and steering stability, reduces noise, and improves fuel efficiency by reducing tire deformation while driving. In addition, the curing process has been improved and natural materials are used, making it environmentally friendly and minimizing cost increases. In addition, it secures a level of 50 to 100% of the characteristics of existing petroleum-based high-performance materials, providing the effect of eliminating performance and cost disadvantages compared to using existing materials.

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

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

The present invention maintains the physical properties of the aramid-polyamide 66 hybrid cord, which is a cap ply cord for existing high-performance radial tires, while using non-petroleum-based materials or plying cellulose artificial fibers and polyester fibers to reduce costs. This is technology related to hybrid cords, their manufacturing methods, and eco-friendly radial tires using them.

The hybrid cord, which is a combination of cellulose artificial fiber and polyester fiber according to the present invention, replaces the existing thermostable aramid with cellulose artificial fiber, and replaces polyamide 66 with polyester to produce cellulose artificial fiber, an eco-friendly material. By using it, the amount of eco-friendly materials used can be increased when manufacturing tires, and it can provide the advantage of being relatively cheaper than aramid. In addition, if polyamide 66 fiber, which reduces the competitiveness of tire manufacturing costs due to limited suppliers, is replaced with polyester, the raw material price can be reduced by 50 to 90% compared to existing polyamide 66, thus reducing cost. Competitiveness can also be secured from that perspective.

Currently, non-petroleum-based fiber materials that are commercially competitive include Viscose Rayon, Tencel, and Lyocell, which are fibers obtained by regenerating or dissolving cellulose. Since these fibers use cellulose, which exists in infinite quantities in the natural world, they have the advantage that raw materials can be secured forever as long as plants exist. Compared to existing petroleum-based synthetic polymer materials, it has the disadvantage that the energy and cost consumed in cellulose processing can be relatively high, but it has the great advantage of having heat-stable characteristics like aramid. 100 years have passed since the first regenerated cellulose fiber appeared on the market, but in a larger context, the original Viscose Rayon has not yet taken its place among synthetic polymer fiber materials, and Lyocell and Tencel, which were developed at the end of the 20th century, Eco-friendly cellulose artificial fibers using the same NMMO (N-Methylmorpholine N-Oxide) as a solvent have also been developed and are gaining prominence in the textile materials market. In particular, in the case of Lyocell and Tencel, unlike viscose rayon, NMMO, a heterocyclic amine oxide that is harmless to the human body, is used as a solvent, so carbon disulfide (CS ₂ ) is not used at all, and eco-friendly features are shown in the fiberization process. In addition, since many advanced Rayon manufacturing processes are being developed and applied in recent years with sealing and solvent recovery at 100% throughout the entire process, it is somewhat difficult to argue that Viscos Rayon is also environmentally harmful.

When applying the cellulose artificial fiber as described above as a fiber cord of a pneumatic radial tire, a certain portion of the physical properties of Para-Aramid, which is expensive and has excellent thermal and mechanical properties due to the thermal stability possessed by the cellulose artificial fiber, are used as fiber cords of pneumatic radial tires. It can be expected that it can be reproduced. Due to the nature of the material, Para-Aramid has a Young's Modulus of more than 500 g/d and a breaking strength of more than 20 g/d, while Super Grade viscos Rayon, which is used for tire cords, has a strength of more than 5 g/d. Because it has d-level strength (breaking strength), it lacks reinforcing performance as a cap ply when used in the same amount as Para Aramid, so there is a disadvantage that the amount used must be increased. In particular, increasing the EPI (End per Inch, number of code strands per inch width) has a very limited range as there may be problems maintaining appropriate code spacing, so a method of increasing the fineness of the code may be desirable, which ultimately leads to By increasing the thickness of the cap ply layer, the weight of the tire increases. Nevertheless, its much lower cost compared to aramid and its advantages as an eco-friendly material appear to more than compensate for the above disadvantages.

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

In addition, if PEF (Polyehtylene furanoate, IUPAC name: Poly ethylene 2,5-furanodicarboxylate) is used instead of PET, it is possible to use close to 100% bio-derived polyester material. PEF is manufactured by replacing the terephthalate monomer of existing general-purpose PET with 2,5-FuranDiCarboxylic Acid (FDCA). FDCA can be obtained through dehydration from monosaccharides and polysaccharides, and from by-products generated while carbonizing wood. It is a bio-derived monomer that can also be obtained. In other words, when PEF is obtained by condensation polymerization of biomass ethylene glycol and FDCA, 100% naturally derived (Bio Derived) polyester is obtained.

The polyester obtained in this way can be fiberized and twisted with cellulose artificial fibers to produce an eco-friendly high modulus cap ply. The cellulose artificial fiber and polyester fiber are manufactured into plied yarn through Direct Cabler, 2 for 1 Cabler, or Ring Twister.

The reason for using polyester instead of using only cellulose artificial fibers is that tensile deformation of at least 2 to 5% in the tread circumferential direction is inevitable during the curing process during the tire manufacturing process, so materials with thermoplastic properties and plied yarns are used. This is to enable heat setting during cooling after tensile deformation when heat and tensile force are applied during the vulcanization process. In the curing process, the tire is inflated and adhered to the mold, and the cap ply wound in the circumferential direction must be tightly adhered with a pure tension of about 2 to 5%. If aramid is applied to the cap ply alone or only cellulose artificial fiber is used for the cap ply, When applied to plies, not only is the resistance large when deformed, but also the force to return to the original length upon cooling after completion of the vulcanization process is large, resulting in a defective tire.

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

The cellulose artificial fiber-polyester hybrid cord obtained by twisting the yarn 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 developed, and if it exceeds 5:1, thermal stability is too strong, resulting in tensile properties related to manufacturability and stress values in the low elongation range of 1 to 4%. There may be a downside 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 fixed fineness is less than 1,000 denier, there is a possibility that the cap ply may be cut during high-speed driving due to insufficient reinforcement. If the fineness is more than 5,000 denier, the cord diameter becomes 0.8 mm or more, which further increases the tire weight and reduces fuel efficiency. has a drawback.

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 in Equation 1 below is less than 100, strength and processability may be reduced due to a lack of cord focusing force, and when twisted yarn with a twist coefficient of more than 250 is used, the cord strength and modulus decrease, making it difficult to achieve the desired performance. 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 plied yarn obtained by the above method is subjected to heat treatment after weaving to obtain dip fabric. At this time, in the heat treatment process, the cord is immersed and dried in RFL (Resorcinol Formaldehyde Latex) to improve the dimensional stability of the cord and for heat setting and adhesion to the skim compound, and then a crosslinking reaction of the RFL is caused through a chemical reaction. . Here, RFL is a composition of Resorcinol Formaldehyde and Latex. Resorcinol Formaldehyde performs the role of adhesion to fibers, and Latex performs the role of compounding and causing vulcanization reaction, respectively. Recently, due to the environmental hazard issue of formaldehyde, dipping recipes that exclude formaldehyde are being studied, and some tire cord manufacturers and tire manufacturers 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, before being applied as a cap ply for a tire. Another method is to manufacture the single end dip cord obtained through heat treatment of the single end cord after the plied yarn into a strip shape through an extrusion process, and then wind it in the circumferential direction on the steel belt layer in the molding process to form a cap ply. there is.

Here, the hybrid cord rolled product or hybrid cap ply semi-finished product can be wound in the 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, efficiency decreases in the semi-finished product preparation process and the cap ply winding process during the molding process also takes longer, reducing productivity. If the cap ply width exceeds 25 mm, the cap ply angle may deviate by more than -7 degrees or +7 degrees relative to the circumferential direction of the tire, so the conicity (wheel cross-sectional slope) of the tire uniformity may be disadvantageous. In terms of PRAT (Plysteer residual Algning Torque), there is also a disadvantage that the directionality can vary greatly depending on the winding direction.

In the hybrid cord rolled product or capply 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 gap between the hybrid cord and the adjacent compound or other adjacent cords (carcass cord, belt cord) becomes narrow and stress concentration or change in stress increases, so running durability is disadvantageous and if it exceeds 2.0 mm. If this is done, more skim compound than necessary is used, which is disadvantageous in terms of tire weight.

In addition, the spacing between the hybrid cords is preferably in the range of 0.13 mm to 0.25 mm. If the gap between hybrid cords is less than 0.13 mm, cracks can easily propagate, which reduces driving durability. If it is more than 0.25 mm, the cords may not be used sufficiently, resulting in insufficient reinforcement.

The cellulose artificial fiber-polyester hybrid cord preferably has a break elongation of 8% to 12% in the state of a dip cord containing an adhesive. If it is less than 8%, breakage occurs due to stress transfer to the cap ply due to centrifugal force during high-speed driving. This may occur, and if it exceeds 12%, it is difficult to sufficiently develop the thermal stability of the cellulose artificial fiber.

It is preferable that the elastic modulus ratio of the cellulose artificial fiber-polyester hybrid cord satisfies the conditions 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 0 to 2% range is high, it becomes difficult to manufacture smoothly during the vulcanization process (circumferential expansion of more than 2% proceeds smoothly). However, if there is an obstruction, it appears as a tire defect). Second, because the elastic modulus 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 section. There is a downside to this as it may lead to inadequacies in the role.

<식 2>

<Equation 2>

here ,

△(2% - 0%): Slope between 0 and 2% on the force-tensile (strain) curve

△(8% - 7%): Slope of 7~8% section on the force-tensile (strain) curve

The cellulose artificial fiber-polyester hybrid cord must be manufactured to have a tensile strength of at least 14 kgf or more as of 1 end. If the strength is lower than this, there is a risk of an accident occurring where the cap fly cord is cut due to centrifugal force during high-speed driving.

When applying the cellulose man-made fiber-polyester hybrid cord of the present invention to a radial pneumatic tire, the angle of the steel belt layer is important. In particular, when the belt angle is set to 31 degrees or more to improve high-speed durability, the tensile force that the reinforcement belt must share increases, and as a result, the cellulose artificial fiber-polyester hybrid cord has lower strength than the hybrid cord containing aramid. When used, an accident may occur where the cap fly cord is cut. For this reason, when using the cellulose artificial fiber-polyester hybrid cord of the present invention, it is preferable that the steel belt angle of the radial pneumatic tire to be applied is in the range of 24 degrees to 30 degrees. If the steel belt angle is less than 24 degrees, the sharing ratio of the tensile force caused by centrifugal force borne by the steel belt increases, so the reason for using the cellulose artificial fiber-polyester hybrid cord is reduced, and if the steel belt angle exceeds 30 degrees, the reason for using the cellulose artificial fiber-polyester hybrid cord is reduced. Because the change in stress value applied to the end of the steel belt cord becomes larger, high-speed driving durability is disadvantageous.

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

Referring to FIG. 2, the tire includes a tread portion (1), a sidewall portion (2), and a bead portion (3). A carcass layer (4) is installed between the pair of left and right bead portions (3), and both ends of the carcass layer (4) in the tire width direction are positioned around the bead portion (5) from the inside of the tire to the outside. It winds 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 can 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 it. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein.

[ Manufacturing example: Manufacturing of hybrid cord ]

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

According to one embodiment of the present invention, Rayon 1650D/2+PET 1000D/1 was applied in Example 1, and Lyocell 1100D/2+P1000D/1 was applied in Example 2.

The structure and physical properties of each cord, and the results derived from the indoor driving test and actual vehicle performance test of the tire (225/45R17) manufactured using the cords are shown in Table 1 below.

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 27EPI Aramid 1500D/2+ Polyamide 66 1260D/1
20EPI Rayon 1650D/2+
PET 1000D/1
30EPI Lyocell 1100/2+
PET 1000D/1
30EPI Lyocell 1100D/2 + PEF 1000D/1 30EPI30EPI Topping Gage 1.0mm 1.1mm 1.2mm 1.2mm 1.2mm 1.2mm Cord1 strand
strong 14.5kgf 34kgf 58kgf 19kgf 17kgf 17.5kgf Strong/inch (1 strand strong 391kgf/inch 918kgf/inch 1,160kgf/inch 570kgf/inch 510kgf/inch 525kgf/inch LASE (2%) 1.2kgf 3.8kgf 4.5kgf 3kgf 2.9kgf 3.0kg LASE (2%)/inch 32.4kgf/inch 54kgf/inch 90kgf/inch 90kgf/inch 88kgf/inch 90kgf/inch LASE(5%) 3.1kgf 15kgf 26kgf 10kgf 9kgf 9.4kgf LASE(5%)/inch 83.7kgf/inch 405kgf/inch 520kgf/inch 300kgf/inch 270kgf/inch 282kgf/inch standard 245/40R18Y ← ← ← ← ← Application area Cap Ply (1 Ply) ← ← ← ← ← weight 11.4 kg 11.45 11.5 11.5 11.5 ← Belt Angle 29 degrees 29 degrees 29 degrees 29 degrees 29 degrees ← Dynamic profile (growth in circumference while driving)
(increased diameter during 300kph) 20mm 10mm 7mm 10mm 12mm 11.5mm rotation 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 Operation 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 Rolls) (Index) 100 200 230 140 135 180

※ If the index is 100 or higher, it is better than Comparative Example 1, and if it is lower, it is worse than Comparative Example 1. However, the lower the index, the better the rolling resistance.

Uniformity is an index value that combines values such as R1H and conicity measured through a uniformity meter. Based on Comparative Example 1, the higher the value, the more advantageous. Rolling resistance was measured using equipment owned by Hankook Tire, and was expressed as an index based on the RRc value of Comparative Example 1 as 100. The higher the index value, the more advantageous it is for rolling resistance. High-speed driving durability was tested using a drum-type driving durability tester by increasing the speed by 20 km/h to 30 km/h every 10 minutes after starting driving. In addition, the dynamic profile used a dedicated test facility to measure the growth of the circumference due to centrifugal force according to the driving speed, and measured and recorded 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 is expressed as an index of 100, and a value higher than 100 indicates superiority over Comparative Example 1, but a lower rotation resistance indicates superiority. In addition, steering stability, ride comfort, and noise are indices evaluated by test drivers through driving the actual vehicle. Comparative Example 1 is set as index 100, and a higher value indicates superiority.

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

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

Examples 1 and 2 are about tires manufactured with a cap ply made by twisting cellulose artificial fiber and PET. Since the strength is lower than that of aramid, the EPI was slightly increased, and the cellulose artificial fiber and PET, a thermoplastic material, were used in Example 2. :1 triad structure was applied.

It can be seen that in Examples 1 and 2, the steering stability and high-speed durability performance are improved compared to Comparative Example 1 in which the existing N66 840D/2 27PI is applied as 1Ply. On the other hand, although it is slightly inferior to the existing aramid-nylon hybrid, there is a significant difference from Comparative Example 1, which used only 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 is an advantage.

Example 3 is a case where the cap ply is made of 100% naturally derived material. Since the tensile modulus of PEF is higher than that of PET, it is characterized by a higher slope in terms of load-tensile characteristics. Since PEF has not yet been 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 total percentage of textile cords used in tires to non-petroleum products.

1: Tread part
2: Side wall part
3: Bead part
4: Steel belt layer
5: Belt layer

Claims (16)

In tires,
Hybrid code is applied to the cap fly,
Equipped with a steel belt layer,
The hybrid cord is made by twisting cellulose artificial fibers and polyester fibers,
The orientation angle of the cap ply on the tire circumference is in the range of -7 degrees to +7 degrees,
A tire characterized in that the angle of the steel belt layer applied to the tire is 24 degrees to 30 degrees. According to paragraph 1,
A tire, characterized in that the cellulose artificial fiber is at least one selected from viscose rayon, regenerated cellulose fiber using carbon disulfide, lyocell, tencel, and cellulose artificial fiber manufactured from pulp. According to paragraph 1,
The polyester fiber is one or more selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and polyethylene furanoate (PEF). Featured tires. According to paragraph 1,
A tire, wherein the polyester fiber is bio-derived polyester. According to paragraph 1,
A tire characterized in that the polyester fiber is PET manufactured by reacting biomass ethylene glycol and terephthalic acid. According to paragraph 1,
A tire characterized in that the polyester fiber is Polyethylene Furanoate (PEF) manufactured by reacting 2,5-FuranDiCarboxylic Acid (FDCA) and ethylene glycol. According to paragraph 1,
A tire characterized in that the polyester fiber is Polyethylene Furanoate (PEF) manufactured by reacting biomass ethylene glycol with 2,5-FuranDiCarboxylic Acid (FDCA). According to paragraph 1,
A tire characterized in that the quantitative fineness of the hybrid cord is greater than 1,000 denier and less than 5,000 denier. According to paragraph 1,
The hybrid cord is a tire characterized in that the twist coefficient 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 paragraph 1,
The hybrid cord is a tire characterized in that the ratio of cellulose artificial fiber and polyester is 1:5 to 5:1. delete According to paragraph 1,
The hybrid cord is a tire characterized in that the spacing between cords is 0.1 mm to 0.25 mm. delete delete According to paragraph 1,
A tire characterized in that the elastic modulus ratio for each section of the hybrid cord satisfies Equation 2 below.

<Equation 2>
In equation 2,
△(2% - 0%): Slope between 0 and 2% on the force-tensile (strain) curve
△(8% - 7%): Slope of 7~8% section on the force-tensile (strain) curve According to paragraph 1,
A tire characterized in that, in the dip cord state of the hybrid cord, the breaking elongation range is 8% to 12%.