A polyurethane-based composite, a non-pneumatic specialty tire, and methods of making the same

Abstract

The application discloses a polyurethane-based composite material, a special tire without inflation and a preparation method thereof, and relates to the technical field of special tires. The polyurethane-based composite material is composed of a polyurethane matrix and modified carbon black, wherein the modified carbon black is prepared by modifying composite carbon black with a two-component silane coupling agent. By modifying the composite carbon black, the material strength and fatigue resistance of the polyurethane-based composite material can be effectively improved, and when the polyurethane-based composite material is applied to the preparation of the special tire without inflation, the mechanical properties, load-carrying capacity and service life of the special tire without inflation can be improved, a new technical scheme is provided for the field of special tire manufacturing, and the development of high-performance, safe and environment-friendly tire products is promoted.

Description

Technical Field

[0001] This invention relates to the technical field of special tires, and in particular to a polyurethane-based composite material, a pneumatic-free special tire, and a method for preparing the same. Background Technology

[0002] With the development of modern industry and transportation, the performance requirements for special tires are becoming increasingly stringent. For example, special vehicles such as police and fire trucks require extremely high tire performance due to their special operations. However, traditional pneumatic tires have gradually revealed their limitations due to the risk of tire blowouts and inconvenient maintenance, making it difficult to meet the performance requirements of special vehicles. Therefore, in order to solve the problems of traditional pneumatic tires, pneumatic-free tires have emerged.

[0003] Currently, pneumatic tires are gradually becoming a research hotspot due to their advantages such as being maintenance-free and puncture-free. Existing pneumatic tire technologies typically employ complex internal structures (such as honeycomb or spoke structures) to provide support, combined with specific materials and special manufacturing processes, to ensure that their quality and performance meet the performance requirements of special vehicles.

[0004] However, existing pneumatic tire technology still has significant shortcomings. On the one hand, while the complex internal structure provides the necessary support for the tire, it also leads to a significant increase in rolling resistance, 20%-50% higher than traditional pneumatic tires, directly affecting the vehicle's fuel economy and power performance. On the other hand, due to the lack of cushioning from the pneumatic inner layer, pneumatic tires offer poor comfort when facing complex road conditions, failing to effectively absorb road impacts and resulting in reduced vehicle stability. Furthermore, the manufacturing process of existing pneumatic tires is relatively complex, resulting in low production efficiency and high manufacturing costs. Moreover, their load-bearing capacity, tread friction, and speed rating are limited, making it difficult to meet the needs of heavy vehicles or high-speed driving. Summary of the Invention

[0005] In order to optimize the material formulation, structural design and production process of airless special tires, improve production efficiency while reducing production costs, and improve the shock absorption performance and comfort of existing airless special tires, this application provides a polyurethane-based composite material, an airless special tire and its preparation method.

[0006] Firstly, the polyurethane-based composite material provided in this application adopts the following technical solution:

[0007] A polyurethane-based composite material, comprising the following raw materials in parts by weight:

[0008] Polyester polyol: 100 parts;

[0009] Polyisocyanates: 50-65 parts;

[0010] Modified carbon black: 15-40 parts;

[0011] Chain extender: 5-8 parts;

[0012] Catalyst: 0.4-0.5 parts;

[0013] The modified carbon black is prepared by modifying composite carbon black with a modifying solution, wherein the modifying solution is a mixed aqueous solution of a two-component silane coupling agent, and the composite carbon black is a mixture of low-hysteresis carbon black and high-reinforcing carbon black.

[0014] By adopting the above technical solutions, the material strength and fatigue resistance of polyurethane-based composite materials can be effectively improved. When applied to the preparation of airless tires, this will help improve the mechanical properties, load-bearing capacity and service life of airless special tires, providing a brand-new technical solution for the field of special tire manufacturing and promoting the development of high-performance, safe and environmentally friendly tire products.

[0015] Optionally, the modified solution is specifically a mixed aqueous solution of the silane coupling agent KH550 and the silane coupling agent KH560, wherein the mass ratio of the silane coupling agent KH550 to the silane coupling agent KH560 is 1:(1-1.5).

[0016] By adopting the above technical solution, a modified solution is prepared by mixing silane coupling agent KH550 and silane coupling agent KH560 in a certain proportion. The resulting two-component silane system can construct a multifunctional graft layer on the surface of composite carbon black through the division of labor of differentiated functional groups, which is beneficial to improving the dispersibility of composite carbon black in polyurethane matrix and further enhancing the interfacial interaction between composite carbon black and polyurethane matrix.

[0017] Optionally, the modification treatment of the modified carbon black includes the following steps:

[0018] The composite carbon black is added to the modification solution at 5-10 wt%, heated to 55-60℃, stirred and dispersed thoroughly, and reacted for 1-3 hours under inert gas protection. After filtration, a modified carbon black is obtained.

[0019] By adopting the above technical solution, the preparation process of modified carbon black is simple and suitable for mass production in factories.

[0020] Secondly, the airless special tire provided in this application adopts the following technical solution:

[0021] A special tire that does not require inflation includes an integrally molded outer tire layer and an inner tire layer, wherein both the outer tire layer and the inner tire layer are made of a polyurethane-based composite material as described in any of the above claims.

[0022] The outer layer of the tire is a soft polyurethane layer, which also includes 6-10 parts of plasticizer and 15-20 parts of modified carbon black by mass. The mass ratio of low-hysteresis carbon black to high-reinforcing carbon black in the modified carbon black is (3-5):(5-7). The outer peripheral surface of the tire is also coated with an anti-puncture coating.

[0023] The inner layer of the tire is a rigid polyurethane layer, and the modified carbon black in the rigid polyurethane layer is 35-40 parts by mass. The mass ratio of low-hysteresis carbon black to high-reinforcing carbon black in the modified carbon black is (5-6):(4-5). Several sets of buffer holes are also provided on the side of the inner layer of the tire, and the buffer holes are evenly distributed along the circumference of the inner layer of the tire.

[0024] By adopting the above technical solution, a novel double-layer structure design of the tire outer and inner layers is used. Different amounts of modified carbon black are used in the outer and inner layers of the polyurethane-based composite material, which facilitates a perfect combination of high friction, high durability, and excellent shock absorption in pneumatic tires. The outer layer uses a polyurethane-based composite material formulated with plasticizers and a small amount of modified carbon black. This not only reduces the hardness of the outer layer and improves its wear resistance, but also enhances its grip and service life. Combined with a puncture-resistant coating, it improves the puncture resistance and wear resistance of the outer layer and further enhances the tire's surface performance. The inner layer uses a polyurethane-based composite material formulated with a large amount of modified carbon black, which effectively improves the hardness and mechanical strength of the inner layer, resulting in higher support rigidity. Combined with buffer holes in the inner layer, these holes absorb impact energy through compression deformation, creating a cushion-like shock absorption effect when the tire is subjected to low-frequency vibrations such as vertical loads, thus improving the overall handling stability of the tire.

[0025] Optionally, the puncture-resistant coating is specifically made of thermoplastic polyurethane coating, and the coating thickness is 0.3-0.5 mm.

[0026] By adopting the above technical solutions, it is beneficial to improve the puncture resistance and wear resistance of the outer layer of the tire, and further enhance the surface performance of the tire.

[0027] Optionally, the buffer hole includes an outer hole and an inner hole, wherein the diameter of the outer hole is smaller than that of the inner hole, and they are staggered.

[0028] By adopting the above technical solution, through the staggered arrangement of the outer and inner circular holes, the impact energy can be absorbed by the geometric deformation of the buffer holes while maintaining the lateral support rigidity of the inner layer of the tire, which is beneficial to improving the handling stability of the tire.

[0029] Optionally, the number of outer and inner circular holes is 12-16.

[0030] By adopting the above technical solution and reasonably controlling the number of buffer holes, it is beneficial to improve the shock absorption effect of the inner layer of the tire while ensuring high support rigidity, and further balance the relationship between the two.

[0031] Thirdly, the method for preparing a pneumatic-free special tire provided in this application adopts the following technical solution:

[0032] A method for preparing a pneumatic-free special tire includes the following steps:

[0033] S1. Weigh each raw material precisely according to the tire outer layer formula and the tire inner layer formula, stir and disperse them thoroughly and degas them under vacuum to obtain tire outer layer masterbatch and tire inner layer masterbatch respectively.

[0034] S2. Preheat the mold to 65-70℃, and then pour the masterbatch for the outer layer of the tire into the mold according to the design thickness of the outer layer of the tire. During the pouring process, start the centrifugal device, keep the mold speed at 500-800r / min and continue to centrifuge for 10-15min for pre-vulcanization. After the centrifugation is completed, the tire outer layer blank is formed.

[0035] S3. According to the design thickness of the inner layer of the tire, pour the masterbatch for the inner layer of the tire into the mold in a certain quantity, heat the mold to 80-83℃ for vulcanization, and the vulcanization time is 3-4 hours. After the reaction is completed, let the material cool naturally to room temperature, demold and take it out, and uniformly coat the outer surface of the tire with an anti-puncture coating. After drying, a special tire that does not require inflation is obtained.

[0036] By adopting the above technical solution, the preparation process is simple and efficient, requires no harsh conditions, and can be completed using conventional equipment, which is conducive to industrialization.

[0037] Optionally, in step S1, while stirring and dispersing each raw material, ultrasonic waves are used to assist in dispersion, wherein the vibration frequency of the ultrasonic waves is 20-30kHz, and the dispersion time is ensured to be no less than 15 minutes.

[0038] By adopting the above technical solution and using ultrasonic-assisted dispersion, the aggregation or uneven dispersion of modified carbon black in the system can be effectively prevented.

[0039] Optionally, in step S2, the mold is an integrated mold that includes a tread vulcanizing mold and a support injection mold, wherein the tread vulcanizing mold is used to form the outer layer of the tire, and the support injection mold is used to form the inner layer of the tire and the buffer holes formed on the inner layer of the tire.

[0040] By adopting the above technical solution, the outer and inner layers of the tire can be formed simultaneously using an integrated mold. This not only shortens the production cycle by 40%-60%, but also simplifies the production process and makes it easier to industrialize, thus enabling the large-scale production of airless special tires.

[0041] In summary, the technical solution of this application has at least one of the following beneficial effects:

[0042] 1. By modifying composite carbon black, the material strength and fatigue resistance of polyurethane-based composite materials can be effectively improved. As a result, when it is used to prepare airless tires, it is beneficial to improve the mechanical properties, load-bearing capacity and service life of airless special tires.

[0043] 2. By adopting a novel double-layer structure design for the outer and inner layers of the tire, and using polyurethane-based composite materials with different amounts of modified carbon black for the outer and inner layers respectively, it is beneficial for the airless special tire to achieve a perfect combination of high friction, high durability and excellent shock absorption.

[0044] 3. The preparation process is simple and efficient, requiring no harsh conditions, and can be completed using conventional equipment, making it easy to industrialize. Attached Figure Description

[0045] Figure 1 This is a SEM image of a polyurethane-based carbon black composite material prepared in Example 1 of this application.

[0046] Figure 2 This is a schematic diagram of the structure of a non-pneumatic special load-bearing tire prepared in Application Example 1 of this application.

[0047] Figure 3 This is a schematic diagram of the structure of a non-pneumatic special load-bearing tire prepared in Application Example 2 of this application.

[0048] Explanation of reference numerals in the attached figures:

[0049] 1. Tire outer layer; 11. Puncture-resistant coating; 2. Tire inner layer; 21. Outer hole; 22. Inner hole. Detailed Implementation

[0050] The present application will be further described in detail below with reference to the accompanying drawings, preparation examples, embodiments and comparative examples.

[0051] The polyester polyol was specifically purchased from Huada Chemical for CPU (cast polyurethane elastomer) polyester polyol, specifically grade ODX-218, with a molecular weight of 2000 (MW).

[0052] Both low-hysteresis carbon black and high-reinforcing carbon black were purchased from Evonik Degussa, with the low-hysteresis carbon black grade being N660 and the high-reinforcing carbon black grade being N326.

[0053] The thermoplastic polyurethane coating was specifically purchased from Fenyangtang.

[0054] Preparation Example

[0055]

Preparation Example 1

[0056] A modified carbon black is prepared by impregnating and modifying composite carbon black with a modifying solution.

[0057] In this preparation example, the modified solution is a mixed aqueous solution of silane coupling agent KH550 and silane coupling agent KH560, wherein the mass ratio of silane coupling agent KH550 to silane coupling agent KH560 in the modified solution is 1:1.5, and the concentration of silane coupling agent in the modified solution is 5%.

[0058] In this preparation example, the composite carbon black is a mixture of low-hysteresis carbon black and high-reinforcing carbon black in a 1:1 mass ratio, that is, 40 kg of composite carbon black includes 20 kg of low-hysteresis carbon black and 20 kg of high-reinforcing carbon black.

[0059] A method for preparing modified carbon black includes the following steps:

[0060] 40 kg of composite carbon black was added to the modification solution at 10 wt%, heated to 55 °C, stirred and dispersed thoroughly, and reacted for 3 h under nitrogen protection. After filtration, a modified carbon black was obtained.

[0061]

Preparation Example 2

[0062] A modified carbon black is prepared by impregnating and modifying composite carbon black with a modifying solution.

[0063] In this preparation example, the modified solution is a mixed aqueous solution of silane coupling agent KH550 and silane coupling agent KH560, wherein the mass ratio of silane coupling agent KH550 to silane coupling agent KH560 in the modified solution is 1:1, and the concentration of silane coupling agent in the modified solution is 5%.

[0064] In this preparation example, the composite carbon black is a mixture of low-hysteresis carbon black and high-reinforcing carbon black in a mass ratio of 3:7, that is, 40 kg of composite carbon black includes 12 kg of low-hysteresis carbon black and 28 kg of high-reinforcing carbon black.

[0065] A method for preparing modified carbon black includes the following steps:

[0066] 40 kg of composite carbon black was added to the modification solution at 5 wt%, heated to 60 °C, stirred and dispersed thoroughly, and reacted for 2 h under nitrogen protection. After filtration, a modified carbon black was obtained.

[0067]

Preparation Example 3

[0068] A modified carbon black, which differs from [Preparation Example 2] in that it is a different composite carbon black.

[0069] In this preparation example, the composite carbon black is a mixture of low-hysteresis carbon black and high-reinforcing carbon black in a mass ratio of 6:4, that is, 40 kg of composite carbon black includes 24 kg of low-hysteresis carbon black and 16 kg of high-reinforcing carbon black.

[0070]

Preparation Example 4

[0071] A modified carbon black, which differs from [Preparation Example 2] in that it is a different composite carbon black.

[0072] In this preparation example, no low-hysteresis carbon black was added to the composite carbon black.

[0073]

Preparation Example 5

[0074] A modified carbon black, which differs from [Preparation Example 3] in that it is a different composite carbon black.

[0075] In this preparation example, no high-reinforcing carbon black was added to the composite carbon black. Example

[0076]

Example 1

[0077] A polyurethane-based composite material comprising the following raw materials:

[0078] 100kg polyester polyol, 65kg polyisocyanate, 15kg modified carbon black, 8kg chain extender, 0.4kg catalyst and 6kg plasticizer.

[0079] In this embodiment, the polyisocyanate is specifically toluene diisocyanate, the modified carbon black is specifically a modified carbon black prepared in [Preparation Example 1], the chain extender is specifically 1,4-butanediol, the catalyst is specifically dibutyltin dilaurate, and the plasticizer is specifically triacetic acid citrate.

[0080]

Example 2

[0081] A polyurethane-based composite material comprising the following raw materials:

[0082] 100kg polyester polyol, 55kg polyisocyanate, 35kg modified carbon black, 8kg chain extender and 0.5kg catalyst.

[0083] In this embodiment, the polyisocyanate is specifically toluene diisocyanate, the modified carbon black is specifically a modified carbon black prepared in [Preparation Example 1], the chain extender is specifically 1,4-butanediol, and the catalyst is specifically dibutyltin dilaurate.

[0084]

Example 3

[0085] A polyurethane-based composite material comprising the following raw materials:

[0086] 100kg polyester polyol, 60kg polyisocyanate, 20kg modified carbon black, 5kg chain extender, 0.5kg catalyst and 10kg plasticizer.

[0087] In this embodiment, the modified carbon black specifically used is the modified carbon black prepared in [Preparation Example 2], and the other raw materials are the same as in [Example 1].

[0088]

Example 4

[0089] A polyurethane-based composite material comprising the following raw materials:

[0090] 100kg polyester polyol, 50kg polyisocyanate, 40kg modified carbon black, 5kg chain extender, 0.5kg catalyst.

[0091] In this embodiment, the modified carbon black specifically used is the modified carbon black prepared in [Preparation Example 3], and the other raw materials are the same as in [Example 1]. Comparative Example

[0092] Comparative Example 1

[0093] A polyurethane-based composite material, which differs from [Example 3] in that it does not contain modified carbon black.

[0094] In this comparative example, composite carbon black was used to replace modified carbon black in equal amounts. The composite carbon black was a mixture of low-hysteresis carbon black and high-reinforcing carbon black in a mass ratio of 3:7, which included 6 kg of low-hysteresis carbon black and 14 kg of high-reinforcing carbon black.

[0095] Comparative Example 2

[0096] A polyurethane-based composite material, which differs from [Example 4] in that it does not contain modified carbon black.

[0097] In this comparative example, composite carbon black was used to replace modified carbon black in equal amounts. The composite carbon black was a mixture of low-hysteresis carbon black and high-reinforcing carbon black in a mass ratio of 6:4, which included 24 kg of low-hysteresis carbon black and 16 kg of high-reinforcing carbon black.

[0098] Comparative Example 3

[0099] A polyurethane-based composite material, which differs from [Example 3] in that it uses a different modified carbon black.

[0100] In this comparative example, the modified carbon black specifically used is the modified carbon black prepared in [Preparation Example 4].

[0101] Comparative Example 4

[0102] A polyurethane-based composite material, which differs from [Example 4] in that it uses a different modified carbon black.

[0103] In this comparative example, the modified carbon black specifically used is the modified carbon black prepared in [Preparation Example 5].

[0104] Application examples

[0105]

Application Example 1

[0106] A type of airless special tire, such as Figure 2 As shown, the tire includes an integrally molded outer tire layer 1 and an inner tire layer 2. The outer tire layer 1 is specifically made of a polyurethane-based composite material as described in Example 1, and the inner tire layer 2 is specifically made of a polyurethane-based composite material as described in Example 2.

[0107] In this application example, the outer tire layer 1 accounts for 30% of the total tire thickness. The outer peripheral surface of the outer tire layer 1 is coated with a puncture-resistant coating 11 with a thickness of 0.5 mm. Specifically, the puncture-resistant coating 11 is made of thermoplastic polyurethane coating. The inner tire layer 2 also has several sets of buffer holes on its sidewalls, evenly distributed along the circumference of the inner tire layer 2. Specifically, the buffer holes include 12 outer holes 21 and 12 inner holes 22. The diameter of the outer holes 21 is smaller than that of the inner holes 22, and they are staggered.

[0108] A manufacturing process for a pneumatic-free special tire includes the following steps:

[0109] S1. Weigh each raw material precisely according to the tire outer layer 1 formula and the tire inner layer 2 formula, stir thoroughly and disperse with ultrasonic assistance for 15 minutes, wherein the ultrasonic frequency is 30kHz, and then degas under vacuum to obtain tire outer layer masterbatch and tire inner layer masterbatch respectively.

[0110] S2. Preheat the mold to 70°C, and then pour the masterbatch for the outer layer of the tire into the mold according to the design thickness of the outer layer 1. During the pouring process, start the centrifugal device, keep the mold speed at 800r / min and continue to centrifuge for 15min for pre-vulcanization. After the centrifugation is completed, stop the centrifugation and form the tire outer layer 1 blank.

[0111] S3. According to the design thickness of the inner layer 2 of the tire, the masterbatch for the inner layer of the tire is quantitatively poured into the mold, the mold is heated to 83°C for vulcanization, the vulcanization time is 3 hours, after the reaction is completed, the material is allowed to cool naturally to room temperature, demolded and taken out, and the anti-puncture coating 11 is uniformly coated on the surface of the outer layer 1 of the tire. After drying, the airless special tire is obtained.

[0112] In step S2, the mold used is an integrated mold with a built-in tread vulcanizing mold and a support injection mold. The tread vulcanizing mold is used to form the outer tire layer 1, and the support injection mold is used to form the inner tire layer 2. The support injection mold is also equipped with a positioning rod, which is used as a fixed skeleton for the inner tire layer 2 and to form the buffer holes on the inner tire layer 2, thereby realizing the integrated casting and molding of the outer tire layer 1 and the inner tire layer 2.

[0113]

Application Example 2

[0114] A type of airless special tire, such as Figure 3 As shown, the tire includes an integrally molded outer tire layer 1 and an inner tire layer 2. The outer tire layer 1 is specifically made of a polyurethane-based composite material as described in [Example 3], and the inner tire layer 2 is specifically made of a polyurethane-based composite material as described in [Example 4].

[0115] In this application example, the outer tire layer 1 accounts for 20% of the total tire thickness. The outer peripheral surface of the outer tire layer 1 is coated with a puncture-resistant coating 11 with a thickness of 0.3 mm. Specifically, the puncture-resistant coating 11 is made of thermoplastic polyurethane coating. The inner tire layer 2 also has several sets of buffer holes on its sidewalls, evenly distributed along the circumference of the inner tire layer 2. Specifically, the buffer holes include 16 outer holes 21 and 16 inner holes 22. The diameter of the outer holes 21 is smaller than that of the inner holes 22, and they are staggered.

[0116] A manufacturing process for a pneumatic-free special tire includes the following steps:

[0117] S1. Weigh each raw material precisely according to the tire outer layer 1 formula and the tire inner layer 2 formula, stir thoroughly and disperse with ultrasonic assistance for 15 minutes, wherein the ultrasonic frequency is 20kHz, and then degas under vacuum to obtain tire outer layer masterbatch and tire inner layer masterbatch respectively.

[0118] S2. Preheat the mold to 65°C, and then pour the masterbatch for the outer layer of the tire into the mold according to the design thickness of the outer layer 1. During the pouring process, start the centrifugal device, keep the mold speed at 500r / min and continue to centrifuge for 10min for pre-vulcanization. After the centrifugation is completed, stop the centrifugation and form the tire outer layer 1 blank.

[0119] S3. According to the design thickness of the inner layer 2 of the tire, the masterbatch for the inner layer of the tire is quantitatively poured into the mold, the mold is heated to 80°C for vulcanization, the vulcanization time is 3 hours, after the reaction is completed, the material is allowed to cool naturally to room temperature, demolded and taken out, and the anti-puncture coating 11 is uniformly coated on the surface of the outer layer 1 of the tire. After drying, the airless special tire is obtained.

[0120] In step S2, the mold used is the same as in Application Example 1, but the number of positioning rods in the support injection mold is set according to the number of openings in the design of the airless special tire in this application example.

[0121] Application of comparative examples

[0122] [Application Comparison Example 1]

[0123] A special tire that does not require inflation differs from [Application Example 2] in that the raw material formulas used for the outer tire layer 1 and the inner tire layer 2 are different.

[0124] In this comparative example, the outer tire layer 1 is specifically made of a polyurethane-based composite material as described in [Comparative Example 1], and the inner tire layer 2 is specifically made of a polyurethane-based composite material as described in [Comparative Example 2].

[0125] [Application Comparison Example 2]

[0126] A special tire that does not require inflation differs from [Application Example 2] in that the raw material formulas used for the outer tire layer 1 and the inner tire layer 2 are different.

[0127] In this comparative example, the outer tire layer 1 is specifically made of a polyurethane-based composite material as described in [Comparative Example 3], and the inner tire layer 2 is specifically made of a polyurethane-based composite material as described in [Comparative Example 4].

[0128] Performance test data

[0129] 1. Tensile strength: Tested according to GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber. The tensile strength (MPa) of the outer and inner layers of the tire in each application example was recorded, with the tensile rate set at 500 mm / min.

[0130] 2. Tear strength: Tested according to GB / T 529-2008 Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped specimens), and the tear strength (N / mm) of the outer and inner layers of the tire in each application example and application comparison example is recorded.

[0131] 3. Hardness: Tested according to GB / T 531.1-2008 Vulcanized rubber or thermoplastic rubber - Test method for indentation hardness - Part 1: Shore hardness tester method (Shore hardness) and the Shore hardness (HA) of the outer and inner tire layers in each application example and application comparison example is recorded.

[0132] 4. Wear Volume: Tested according to GB / T 9867-2008 "Determination of Abrasion Resistance of Vulcanized Rubber or Thermoplastic Rubber (Rotary Drum Abrasion Tester Method)", the surface wear volume (mm) of the tire outer layer after removing the puncture-resistant coating was recorded in each application example and comparative example. 3 ).

[0133] 5. Dynamic compression heat generation performance: Tested according to GB / T1687.1-2016 Determination of temperature rise and fatigue resistance of vulcanized rubber in flexural test - Part 1: Basic principle, and the dynamic compression heat generation value (°C) of the outer and inner layers of the tire in each application example and application comparison example was recorded.

[0134] Table 1. Test data on the outer layer performance of special tires

[0135]

[0136] Table 2 Test data of tire inner layer performance for special tires

[0137]

[0138] Combining Application Example 2 and Comparative Example 1 with the data in Table 1-2, it can be seen that the performance of the polyurethane-based composite material prepared by modifying the composite carbon black with a two-component silane coupling agent is improved. When applied to pneumatic tires, the tensile strength and tear strength of both the outer layer 1 and the inner layer 2 of the tire increase. Simultaneously, the wear volume per unit time of the outer layer 1 decreases, and the dynamic compression heat value of both the outer layer 1 and the inner layer 2 also decreases significantly. This indicates that the modified carbon black can effectively improve the mechanical properties, load-bearing capacity, and service life of pneumatic tires. This is likely because the two-component silane coupling agent modification of the composite carbon black significantly enhances the interfacial interaction between the modified carbon black and the rubber compound system, thereby endowing the polyurethane-based composite material with excellent material strength, high-temperature resistance, and fatigue resistance.

[0139] In addition, for the polyurethane-based composite material used in the outer layer 1 of the tire, adding a specific proportion of plasticizer and a small amount of modified carbon black can significantly reduce the hardness of the outer layer 1 of the tire and improve its wear resistance, which in turn helps to enhance the grip and service life of the outer layer 1 of the tire. Moreover, by utilizing its softer elastic properties, the outer layer 1 of the tire can also absorb some of the high-frequency vibrations directly transmitted from the road surface, which helps to improve driving comfort.

[0140] For the polyurethane-based composite material used in the inner layer 2 of the tire, the amount of modified carbon black is further increased, which significantly improves the hardness and mechanical strength of the inner layer 2. This gives the inner layer 2 higher support rigidity. At the same time, the buffer holes opened on the inner layer 2 can absorb the impact energy of the tire through compression deformation. This helps the tire to produce a shock absorption effect similar to an air cushion when subjected to low-frequency vibrations such as vertical loads, which helps to improve the overall handling stability of the tire.

[0141] Combining Application Example 2 and Comparative Example 1-2 with the data in Table 1-2, it can be seen that by using a composite carbon black made by mixing low-hysteresis carbon black and high-reinforcing carbon black in a specific ratio, compared with using a single carbon black, the modified polyurethane-based composite material used in the outer layer 1 or inner layer 2 of a tire exhibits a targeted improvement in performance for both, thus contributing to the overall improvement of tire performance. Specifically, for the outer layer 1, although using a polyurethane-based composite material containing a single high-reinforcing carbon black results in higher mechanical strength, hardness, and wear resistance, its dynamic compression heat value is also higher. This means that some of the dynamic viscoelasticity and dynamic durability of the outer layer 1 are sacrificed, leading to increased tire safety risks and a higher risk of accidents. Conversely, for the inner layer 2, using a polyurethane-based composite material containing a single low-hysteresis carbon black significantly reduces its mechanical strength and hardness, directly affecting the supporting rigidity of the inner layer 2 and the tire's load-bearing capacity.

[0142] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A special tire that does not require inflation, characterized in that, It includes an integrally formed tire outer layer (1) and tire inner layer (2). The outer peripheral surface of the tire outer layer (1) is also coated with an anti-puncture coating (11). The side of the tire inner layer (2) is also provided with a number of buffer round holes, which are evenly distributed along the circumference of the tire inner layer (2). The outer layer (1) of the tire is a soft polyurethane layer, which comprises the following raw materials in parts by weight: 100 parts polyester polyol, 50-65 parts polyisocyanate, 15-20 parts modified carbon black, 5-8 parts chain extender, 0.4-0.5 parts catalyst and 6-10 parts plasticizer; The inner layer (2) of the tire is a rigid polyurethane layer, which comprises the following raw materials in parts by weight: 100 parts polyester polyol, 50-65 parts polyisocyanate, 35-40 parts modified carbon black, 5-8 parts chain extender and 0.4-0.5 parts catalyst; The modified carbon black is prepared by modifying composite carbon black with a modifying solution, wherein the modifying solution is a mixed aqueous solution of a two-component silane coupling agent, and the composite carbon black is a mixture of carbon black N660 and carbon black N326. In the outer layer (1) of the tire, the composite carbon black in the modified carbon black is a mixture of carbon black N660 and carbon black N326 in a mass ratio of (3–5):(5–7). In the inner layer (2) of the tire, the composite carbon black in the modified carbon black is a mixture of carbon black N660 and carbon black N326 in a mass ratio of (5–6):(4–5).

2. The airless special tire according to claim 1, characterized in that: The modified solution is specifically a mixed aqueous solution of silane coupling agent KH550 and silane coupling agent KH560, wherein the mass ratio of silane coupling agent KH550 to silane coupling agent KH560 is 1:(1-1.5).

3. The airless special tire according to claim 1, characterized in that: The modification treatment of the modified carbon black includes the following steps: The composite carbon black is added to the modification solution at 5-10 wt%, heated to 55-60℃, stirred and dispersed thoroughly, and reacted for 1-3 hours under inert gas protection. After filtration, a modified carbon black is obtained.

4. The airless special tire according to claim 1, characterized in that: The puncture-resistant coating (11) is specifically made of thermoplastic polyurethane coating with a coating thickness of 0.3-0.5 mm.

5. A special tire that does not require inflation according to claim 1, characterized in that: The buffer hole includes an outer hole (21) and an inner hole (22). The diameter of the outer hole (21) is smaller than that of the inner hole (22), and they are staggered.

6. A special tire that does not require inflation according to claim 5, characterized in that: The number of outer circular holes (21) and inner circular holes (22) is 12-16.

7. A method for preparing a pneumatic-free special tire, used to prepare a pneumatic-free special tire as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Weigh each raw material precisely according to the formula of tire outer layer (1) and tire inner layer (2), stir and disperse them thoroughly and degas them under vacuum to obtain masterbatch for tire outer layer and masterbatch for tire inner layer respectively. S2. Preheat the mold to 65-70℃, and then pour the masterbatch for the outer layer of the tire into the mold according to the design thickness of the outer layer (1). During the pouring process, start the centrifugal device, keep the mold speed at 500-800r / min and continue to centrifuge for 10-15min for pre-vulcanization. After the centrifugation is completed, stop the centrifugation and form the outer layer (1) blank of the tire. S3. According to the design thickness of the inner layer (2) of the tire, pour the masterbatch for the inner layer of the tire into the mold in a certain amount, heat the mold to 80-83℃ for vulcanization, the vulcanization time is 3-4h, after the reaction is completed, wait for the material to cool naturally to room temperature, demold and take it out, uniformly coat the anti-puncture coating (11) on the surface of the outer layer (1) of the tire, and obtain the airless special tire after drying.

8. The method for preparing a pneumatic-free special tire according to claim 7, characterized in that: In step S1, while stirring and dispersing the raw materials, ultrasonic waves are used to assist in the dispersion. The vibration frequency of the ultrasonic waves is 20-30kHz, and the dispersion time is ensured to be no less than 15 minutes.

9. The method for preparing a pneumatic-free special tire according to claim 7, characterized in that: In step S2, the mold is an integrated mold that includes a tread vulcanizing mold and a support injection mold. The tread vulcanizing mold is used to form the outer layer (1) of the tire, and the support injection mold is used to form the inner layer (2) of the tire and the buffer holes opened on the inner layer (2).

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