Pneumatic tire with recycled polyester cord reinforcement

Abstract

The present disclosure provides a pneumatic tire comprising a reinforcement material including a polyester cord containing recycled PET polymer. The recycled PET polymer has a stress of at least 1.75 g / dtex at 3% elongation and a specific breaking energy of at least 1.75 mjoules / dtex. The recycled PET content in the polyester cord reinforcement may be at least 90%. The polyester cord can be used as carcass reinforcement and / or cap ply reinforcement in the pneumatic tire. The disclosure also provides a method of manufacturing the pneumatic tire and a reinforcement material for pneumatic tires having the specified properties.

Description

[0001] 9081.214

[0002] DESCRIPTION

[0003] PNEUMATIC TIRE WITH RECYCLED POLYESTER CORD REINFORCEMENT

[0004] The present disclosure relates to pneumatic tires, and more particularly to a pneumatic tire, method of manufacturing, and reinforcement material comprising recycled polyester cord reinforcement with superior properties.

[0005] Pneumatic tires are essential components in modem vehicles, providing the critical interface between the vehicle and the road surface. These tires must withstand various road conditions, absorb shocks, dissipate heat, and resist wear and tear. To meet these demanding requirements, tires incorporate textile reinforcing materials in the form of cords.

[0006] Synthetic tire cords are commonly used as reinforcing materials in tires. These cords can be made from various materials, including rayon, nylon 6, nylon 6,6, polyesters, and aramid fibres. Among these, poly (ethylene terephthalate) (PET) and nylon 6,6 have been widely utilized in tire construction. Typically, nylon 6,6 synthetic yam cords are employed in the tire's cap ply zone, while polyester synthetic yarn is used as a carcass element in radial passenger car tires.

[0007] Polyester tire cords offer several advantages, including high strength, durability, modulus, and creep resistance. Additionally, polyester exhibits strong dimensional stability. However, these cords also have limitations, such as low adhesion and fatigue resistance, which have prompted ongoing efforts to address these shortcomings.

[0008] The widespread use of petroleum-based polymers in tire cord production has raised environmental and sustainability concerns. As the global supply of petrochemicals is finite, there is growing recognition of the need to balance scientific development with environmental protection. The accumulation of PET waste in marine and 9081.214 terrestrial environments, along with its potential to carry hazardous colorants and chemicals, poses a significant threat to the natural environment.

[0009] The production of PET from bio-based feedstock or post-consumer waste has emerged as a preferred alternative in recent years. However, achieving closed-loop recycling of PET to improve material utilization and address the existing large quantities of PET waste remains a challenge.

[0010] It has been appreciated that a pneumatic tire with recycled polyester cord reinforcement is needed that overcomes one or more of these problems.

[0011] European patent application EP3753965A1, which relates to the state of the art, discloses a reinforcement and a reinforcing layer for elastomeric products, in particular for vehicle tyres. The invention disclosed in the patent application is that the reinforcement consists of recycled polyethylene terephthalate (PET) fibres.

[0012] State of the art PCT application W02024043707A1 discloses the use of recycled polyethylene terephthalate (PET) fibre, an environmentally friendly rubber reinforcing material. The key features highlighted in the application are that the use of recycled PET fibre reduces environmental impact, and that cord made from recycled PET fibre has physical properties equal to or better than cord made from virgin PET fibre.

[0013] The invention disclosed in another PCT application WO2023155990A1 in the known state of the art relates to an elastomeric product, in particular for vehicle tyres. This product comprises filaments comprising a) recycled polyethylene terephthalate (PET) and b) at least one other material. The other material is selected from the group consisting of b), bl) recycled polymers and b2) polymers of biological origin.

[0014] Polyester tyre cord provides various advantages, including high strength, durability, modulus, and creep resistance. Furthermore, polyester has strong dimensional 9081.214 stability despite having low adhesion and fatigue resistance. As a result, several efforts have been made to restore these shortcomings.

[0015] An elastic modulus (also known as modulus of elasticity) is the unit of measurement of an object's or substance's resistance to being deformed elastically (i.e., non- permanently) when a stress is applied to it.

[0016] The elastic modulus of an object is defined as the slope of its stress-strain curve in the elastic deformation region: A stiffer material will have a higher elastic modulus. An elastic modulus has the form: stress

[0017] 8 = - strain where stress is the force causing the deformation divided by the area to which the force is applied and strain is the ratio of the change in some parameter caused by the deformation to the original value of the parameter. Since strain is a dimensionless quantity, the units of 6 will be the same as the units of stress.

[0018] Elongation values can be defined as EASL or LASE whether related to dtex or not.

[0019] EASL (Elongation at Specific Load): It is the elongation value under certain force. Different EASL values can be obtained for different cord construction.

[0020] LASE (Load at Specific Elongation): It is the opposite of EASL, it specifies the force that must be applied to the cord to reach a certain elongation.

[0021] The present invention related to recycled polyester cord production from tire grade multifilament recycled polyester yam as tire reinforcement having at least 1.75 g / dtex stress at 3% elongation & min. 1.75 mjoules / dtex specific breaking energy. Therefore, it overcomes the sustainability concerns of fossil based origin of cords and improving tyre performance by ensuring of dimensional stability and improving impact resistance.

[0022] The present invention provides a pneumatic tire that incorporates a reinforcement material comprising a polyester cord containing recycled polyethylene terephthalate (PET) polymer. The use of recycled PET polymer in the polyester 9081.214 cord reinforcement offers a sustainable alternative to conventional petroleum-based polymers, addressing environmental concerns associated with the latter. The recycled PET cord exhibits a stress of at least 1.75 g / dtex at 3% elongation and a specific breaking energy of at least 1.75 mjoules / dtex, contributing to the improved performance of the pneumatic tire. This stress value indicates the force required to stretch the cord to a certain extent, providing an indication of the cord 's resistance to deformation under load. A higher stress value at a given elongation suggests a higher resistance to deformation, which can contribute to the tire's structural integrity and durability. The specific breaking energy is a measure of the energy required to break the cord, providing an indication of the cord's toughness. A higher specific breaking energy suggests a higher resistance to breakage, which can contribute to the tire's impact resistance and overall durability.

[0023] This combination of properties can provide a balance of deformation resistance and toughness, contributing to the overall performance of the pneumatic tire. The use of a recycled PET polymer with these properties in the polyester cord reinforcement can provide a sustainable and performance-enhancing solution for pneumatic tire construction.

[0024] In some embodiments, the recycled PET content in the polyester cord reinforcement may be at least 90%. The polyester cord can be utilized as carcass reinforcement and / or cap ply reinforcement in the pneumatic tire, offering flexibility in tire construction. This high percentage of recycled PET content further enhances the sustainability of the pneumatic tire. The polyester cord, containing the recycled PET polymer, can be used as a reinforcement material in various parts of the pneumatic tire. For instance, the polyester cord can be used as carcass reinforcement in the pneumatic tire, providing structural integrity and dimensional stability to the tire. In other instances, the polyester cord can be used as cap ply reinforcement in the pneumatic tire, contributing to the tire's resistance to impacts and its overall durability. 9081.214

[0025] In some aspects, the pneumatic tire includes a reinforcement material that comprises a polyester cord. This polyester cord contains a recycled PET polymer. The use of recycled PET polymer in the polyester cord reinforcement not only provides a sustainable solution to the environmental concerns associated with conventional petroleum-based polymers, but also contributes to the improved performance of the pneumatic tire.

[0026] In addition to the pneumatic tire, the present disclosure also provides a reinforcement material for a pneumatic tire. This reinforcement material comprises a polyester cord containing recycled PET polymer. The recycled PET polymer in the polyester cord of the reinforcement material exhibits the same stress and specific breaking energy properties as described above. This reinforcement material can be used in the manufacture of pneumatic tires, contributing to the tire's performance and sustainability.

[0027] The polyester cord, which forms part of the reinforcement material in the pneumatic tire is composed of recycled PET polymer. In some aspects, the recycled PET content in the polyester cord reinforcement may be at least 90%. This high percentage of recycled PET content further underscores the sustainability of the pneumatic tire, as it reduces the reliance on virgin, petroleum-based polymers.

[0028] In some embodiments, the polyester cord may have a linear density of 1100 dTex. The linear density, or denier, is a measure of the mass per unit length of the cord, and it can influence the cord's mechanical properties and its performance as a reinforcement material in the pneumatic tire. A polyester cord with a linear density of 1100 dTex can provide a balance of strength and flexibility, contributing to the tire's durability and performance.

[0029] The polyester cord may also have a 2-ply construction with a 4.0-8.0 twist multiplier ratio in some cases. The 2-ply construction refers to the number of individual yarns that are twisted together to form the cord, while the twist multiplier ratio refers to the degree of twist applied to the yarns. This specific construction 9081.214 and twist can enhance the cord's tensile strength and dimensional stability, further improving the performance of the pneumatic tire.

[0030] Twist multiplier (TM) is a unit which helps to decide the twist per unit length for different counts from the same raw material. Total Tex) / 9S0 (TWIST PER INCH » TWIST MULTIPLIER * SQRT(Ne) )

[0031] In some aspects, the polyester cord may be composed of recycled PET polymer, have a linear density of 1100 dTex, and a 2-ply construction with a 4.0-8.0 twist multiplier ratio. This combination of properties can provide a balance of strength, flexibility, and dimensional stability, contributing to the overall performance of the pneumatic tire. The use of a polyester cord with these properties in the reinforcement material can provide a sustainable and performance-enhancing solution for pneumatic tire construction.

[0032] In some aspects, the polyester cord may be used as carcass reinforcement in the pneumatic tire structure. The carcass reinforcement is a critical component of the tire, providing structural integrity and dimensional stability. The use of the polyester cord as carcass reinforcement can contribute to the tire's resistance to deformation under load, enhancing its performance in various driving conditions. The recycled PET polymer in the polyester cord can provide the necessary mechanical properties, such as stress and specific breaking energy, for effective carcass reinforcement.

[0033] In some cases, the polyester cord containing recycled PET cord may be incorporated into the carcass reinforcement of the pneumatic tire during the manufacturing process. This can involve arranging the polyester cord in a specific pattern or orientation to optimize its reinforcement properties. The incorporation of the polyester cord as carcass reinforcement can be carried out using conventional tire manufacturing techniques, making it a practical and feasible solution for enhancing the performance and sustainability of pneumatic tires. 9081.214

[0034] In some aspects, the polyester cord may be used as cap ply reinforcement in the pneumatic tire structure. The cap ply is a layer of material that is placed over the belt plies in a radial tire, and it plays a crucial role in maintaining the tire's shape and enhancing its high-speed performance. The use of the polyester cord as cap ply reinforcement can contribute to the tire's resistance to deformation under highspeed conditions, enhancing its performance and safety. The recycled PET polymer in the polyester cord can provide the necessary mechanical properties, such as stress and specific breaking energy, for effective cap ply reinforcement.

[0035] In some aspects, the manufacturing of the pneumatic tire may involve providing a reinforcement material that comprises a polyester cord containing recycled PET polymer. The recycled PET cord may exhibit a stress of at least 1.75 g / dtex at 3% elongation and a specific breaking energy of at least 1.75 mjoules / dtex. The provision of this reinforcement material can be carried out using conventional textile manufacturing techniques, such as spinning and twisting, to produce the polyester cord with the desired properties. The recycled PET polymer used in the polyester cord can be sourced from post-consumer waste, contributing to the sustainability of the pneumatic tire.

[0036] In some cases, the manufacturing process may further involve incorporating the reinforcement material into a pneumatic tire structure. This can be achieved by arranging the polyester cord in a specific pattern or orientation within the tire structure to optimize its reinforcement properties. The incorporation of the polyester cord into the tire structure can be carried out using conventional tire manufacturing techniques, such as calendaring and curing. The polyester cord can be incorporated into various parts of the tire structure, such as the carcass and the cap ply, depending on the specific requirements of the pneumatic tire.

[0037] In some embodiments, the incorporation of the polyester cord into the pneumatic tire structure may involve embedding the cord into the rubber matrix of the tire. This can be achieved by applying a layer of rubber compound onto the cord, followed by curing the rubber to form a strong bond between the cord and the rubber 9081.214 matrix. The embedding of the polyester cord into the rubber matrix can enhance the adhesion between the cord and the rubber, contributing to the durability and performance of the pneumatic tire.

[0038] In some aspects, the manufacturing process may involve adjusting the properties of the polyester cord, such as its linear density and twist, to meet the specific requirements of the pneumatic tire. This can be achieved by modifying the spinning and twisting parameters during the production of the cord. The adjustment of the cord properties can provide flexibility in the design and construction of the pneumatic tire, allowing for the optimization of its performance and sustainability.

[0039] In some aspects, the recycled PET polymer in the polyester cord may exhibit enhanced mechanical properties compared to conventional, fossil-based virgin PET cord. For instance, the recycled PET cord may have a breaking energy that is 30% higher than that of the virgin PET cord. Breaking energy is a measure of the energy required to break the cord, and a higher breaking energy suggests a higher resistance to breakage. This can contribute to the tire's impact resistance and overall durability, enhancing its performance in various driving conditions.

[0040] In some cases, the recycled PET cord may also have an elongation at break that is 25% higher than that of the virgin PET cord. Elongation at break is a measure of the extent to which the cord can be stretched before it breaks, and a higher elongation at break suggests a higher flexibility of the cord. This can contribute to the tire's ability to withstand deformation under load, further enhancing its performance and durability.

[0041] From a performance perspective, the recycled PET in the polyester cord exhibits certain mechanical properties that enhance the performance of the pneumatic tire. As previously described, the recycled PET cord may exhibit a stress of at least 1.75 g / dtex at 3% elongation and a specific breaking energy of at least 1.75 mjoules / dtex. These properties contribute to the tire's structural integrity, dimensional stability, and impact resistance, enhancing its performance in various driving conditions. 9081.214

[0042] In some cases, the recycled PET cord may exhibit enhanced mechanical properties compared to conventional, fossil-based virgin PET cord. For instance, the recycled PET cord may have a breaking energy that is 30% higher and an elongation at break that is 25% higher than that of the virgin PET cord. These enhanced properties can further improve the performance of the pneumatic tire, providing a balance of toughness and flexibility. Test are applied regarding ASTM standards. Greige cord with a total linear density of 1100 dTex, 2 plied and has 4.0-8.0 twist multiplier ratio are underwent 240°C, 1 Kg 60 second exposure then, cooling under tension (0.5 minute), wait (1 hour). Comparing with fossil-based virgin one, R-PET has %30 higher breaking energy and %25 higher elongation at break.

[0043] % LASE development enable tire dimensional stability as well as tire performance improvement.

[0044] In some aspects, the pneumatic tire may be constructed with a radial design, where the polyester cord containing recycled PET polymer is used as both carcass reinforcement and cap ply reinforcement. The carcass reinforcement provides the basic structure of the tire, contributing to its dimensional stability and load-bearing capacity. The cap ply reinforcement, on the other hand, is located above the belt plies and contributes to the tire's resistance to impacts and its high-speed performance. The use of the polyester cord in both these areas of the tire can enhance its overall performance and durability.

[0045] In some cases, the polyester cord may be used as carcass reinforcement in a bias- ply tire. In a bias-ply tire, the cords in the carcass reinforcement are arranged diagonally to the direction of travel, providing a robust structure that can withstand heavy loads. The use of the polyester cord as carcass reinforcement in a bias-ply tire can contribute to the tire's load-bearing capacity and resistance to deformation under load.

[0046] In some embodiments, the polyester cord may be used as cap ply reinforcement in a radial tire. In a radial tire, the cords in the cap ply reinforcement are arranged radially, or perpendicular to the direction of travel, providing a flexible structure 9081.214 that can adapt to various road surface conditions. The use of the polyester cord as cap ply reinforcement in a radial tire can contribute to the tire's flexibility and highspeed performance.

[0047] In some aspects, the polyester cord may be used in combination with other reinforcement materials in the pneumatic tire. For instance, the polyester cord may be used as carcass reinforcement, while other materials, such as steel or aramid fibers, may be used as belt or cap ply reinforcement. This combination of materials can provide a balance of properties, such as strength, flexibility, and dimensional stability, contributing to the overall performance of the pneumatic tire. The use of the polyester cord as carcass reinforcement can be tailored to the specific requirements of the pneumatic tire, providing flexibility in tire design and construction.

[0048] Aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples without losing the effect sought.

Claims

9081.214CLAIMS1. A pneumatic tire, comprising a reinforcement material comprising a polyester cord containing recycled PET polymer, wherein the recycled PET polymer has a stress of at least 1.75 g / dtex at 3% elongation and a specific breaking energy of at least 1.75 mjoules / dtex.

2. The pneumatic tire of claim 1, wherein the recycled PET content in the polyester cord reinforcement is at least 90%.

3. The pneumatic tire of claim 1 or 2, wherein the polyester cord has total linear density of at least 1000 dTex.

4. The pneumatic tire of any of claims 1 to 3, wherein the polyester cord has a 2-ply construction with a 4.0-8.0 twist multiplier ratio.

5. The pneumatic tire of any of claims 1 to 4, wherein the polyester cord is used as carcass reinforcement.

6. The pneumatic tire of any of claims 1 to 4, wherein the polyester cord is used as cap ply reinforcement.

7. The pneumatic tire of any preceding claim, wherein the recycled PET polymer has a stress of 1.80 g / dtex to 1.90 g / dtex, more preferably 1.80 g / dtex at 3% elongation.

8. The pneumatic tire of any preceding claim, wherein the recycled PET polymer has a specific breaking energy of 1.80 mjoules / dtex to 1.90 mjoules / dtex, more preferably 1.80 mjoules / dtex.

9. A method of manufacturing a pneumatic tire, comprising: providing a reinforcement material comprising a polyester cord containing recycled PET polymer, wherein the recycled PET polymer has a stress of at least 1.75 g / dtex at 3% elongation and a specific breaking energy of at least 1.75 mjoules / dtex; and incorporating the reinforcement material into a pneumatic tire structure.

10. The method of claim 9, wherein the recycled PET content in the polyester cord reinforcement is at least 90%.9081.21411. The method of claim 9 or 10, wherein incorporating the reinforcement material comprises using the polyester cord as carcass reinforcement in the pneumatic tire structure.

12. The method of any of claims 9 to 11, wherein incorporating the reinforcement material comprises using the polyester cord as cap ply reinforcement in the pneumatic tire structure.

13. The method of any of claims 9 to 12, wherein the recycled PET polymer has a stress of 1.80 g / dtex to 1.90 g / dtex, more preferably 1.80 g / dtex at 3% elongation.

14. The method of any of claims 9 to 13, wherein the recycled PET polymer has a specific breaking energy of 1.80 mjoules / dtex to 1.90 mjoules / dtex, more preferably 1.90 mjoules / dtex.

Images