A high-load-bearing layered composite solid tire and a preparation method thereof

Abstract

The application discloses a high-load layered composite solid tire and a preparation method thereof, and relates to the field of solid tire manufacturing. The solid tire comprises, from inside to outside, a base rubber layer, a middle rubber layer and a tread rubber layer, each of which adopts a differentiated main rubber system and a reinforcing and filling system; the Shore A hardness of the middle rubber layer is lower than that of the base rubber layer and the tread rubber layer, the 300% modulus of the middle rubber layer is not lower than that of the base rubber layer, and the tensile strength of the middle rubber layer is greater than that of the base rubber layer and smaller than that of the tread rubber layer. The application further discloses a preparation method of the solid tire. After an inner stop ring is fixed to a forming drum, the base rubber layer and the middle rubber layer are formed in sequence, the tread rubber which is plasticized at the same time and is subjected to initial rolling is divided into a main tread and two side edge rubbers, and vulcanization is performed on a tire blank, and the tire blank is matched with a steel ring and a check ring. The scheme is beneficial to the load stability, deformation buffering, tear resistance and wear resistance of the solid tire, and improves the consistency of the layered forming and vulcanization processes.

Description

Technical Field

[0001] This invention relates to the field of solid tire manufacturing, and in particular to a high-load-bearing layered composite solid tire consisting of a base rubber layer, an intermediate rubber layer and a tread rubber layer, and a method for preparing the same. Background Technology

[0002] Solid tires do not rely on internal inflation pressure to maintain load-bearing capacity. They primarily utilize the tire's own rubber material and internal structure to bear vehicle loads, and are widely used in material handling, construction machinery, and other high-load operations. Compared to pneumatic tires, solid tires have a thicker internal rubber structure. During continuous load-bearing and rolling, the stress state and performance requirements of different radial areas vary. Specifically, the inner area near the rim mainly bears the load transfer between the rim and the tire body and serves to stabilize the tire's dimensions, requiring corresponding rigidity and resistance to continuous deformation. The middle area inside the tire body, located between the base and the tread, needs to undergo a certain degree of elastic deformation during load transfer and buffer against impacts and stress changes. The tread area on the outer periphery of the tire is in direct contact with the ground and needs to withstand repeated rolling, friction, localized impacts, and shearing, thus requiring higher performance in terms of wear resistance and tear resistance.

[0003] To address the performance requirements of the different regions mentioned above, existing technologies have proposed using multi-layered rubber structures to manufacture solid tires. For example, CN109535502A – a high-strength solid tire and its preparation method – consists of three parts: a base rubber layer on the inner ring, a tread rubber layer on the outer ring, and a core rubber layer that connects the base rubber layer and the tread rubber layer. Compared to existing technologies, this patent application uses natural rubber and butadiene rubber as the main rubber compounds. In addition to carbon black reinforcement, a small amount of reinforcing fibers are added. The surface of the fibers is first treated with a silane coupling agent to ensure the bonding force between the fibers and the rubber compound. Simultaneously, tackifying resins firmly bond the base rubber layer, tread rubber layer, and core rubber layer, resulting in a solid tire with high strength, wear resistance, and good overall performance. Furthermore, the production process is mature and simple to operate. However, the raw material composition differences between the various rubber layers in this high-strength solid tire are relatively small, making it difficult to meet the performance requirements of different rubber layers.

[0004] Existing technologies include multi-layered solid tires composed of a base layer, intermediate layer, and tread layer, with separate rubber compounds for each layer. However, for high-load-bearing solid tires, the different layers require more than just simple differences in hardness. The base layer, to limit overall deformation under high loads, typically needs to maintain a certain level of rigidity and load-bearing stability; the intermediate layer, to mitigate loads and deformations transmitted from the tread to the base, needs a certain degree of deformation compliance. If compliance in the intermediate region is achieved solely by reducing rubber hardness, its ability to constrain tire deformation under large deformation conditions may be insufficient. Conversely, simply increasing the rigidity of the intermediate layer material may weaken its deformation adaptability as an intermediate buffer zone. Therefore, for high-load-bearing layered solid tires, further improvements are needed to ensure that the intermediate layer, while possessing relatively low hardness, maintains a large deformation mechanical response adapted to its stress location, and achieves a coordinated performance configuration with the base and tread layers.

[0005] Secondly, the base layer, intermediate layer, and tread layer differ in their main rubber, reinforcing materials, and fillers. Their hardness, elongation at a given point, elastic recovery, abrasion resistance, and deformation characteristics under sustained load are not independent of each other. Simply improving one performance indicator of a single layer does not necessarily improve the overall high-load-bearing capacity of the solid tire. For example, while the intermediate layer needs appropriate flexibility, it should also avoid becoming an area of ​​excessive deformation in the tire carcass under sustained or heavy loads. Therefore, further improvements are needed to enhance the material system and performance matching between the three layers, enabling them to collectively adapt to high-load conditions while fulfilling their respective functions.

[0006] On the other hand, the performance of multi-layer solid tires is not only affected by the composition of each rubber layer material, but also by the tire carcass forming and vulcanization process. The base rubber layer, intermediate rubber layer and tread rubber layer have different material compositions and forming requirements. Their plasticizing state, rolling state, belt width and axial forming position all need to be controlled accordingly. Otherwise, it may cause fluctuations in rubber distribution, rubber layer size and forming state, and affect the consistency of subsequent vulcanization.

[0007] Especially during the tread molding process, although the main tread and the edge rubber on both sides of it use the same tread rubber layer material, they have different molding requirements in terms of rubber quantity, tape width, and winding position. If the rubber material is prepared separately, it may increase the difference in rubber material state between different processing batches; if the processing state is exactly the same, it is difficult to take into account the different molding requirements of continuous winding of the main tread and edge rubber on both sides. Therefore, how to keep the source of rubber material and the previous processing state of the main tread and edge rubber consistent, while making them adaptable to different subsequent molding requirements, still needs further improvement.

[0008] In addition, after the tire blanks are wound in multiple layers, they need to go through processes such as sorting, waiting to be put into the mold and vulcanization. The post-forming storage time of different tire blanks and the initial thermal state of the mold between the first mold and subsequent molds in the same production batch may be different, which will cause fluctuations in the forming and vulcanization conditions experienced by different tire blanks.

[0009] Therefore, based on the existing three-layer composite solid tires, it is still necessary to further improve the material performance matching between the base layer, intermediate layer and tread layer, and to reasonably control the process state of tread area forming and tire blank from forming to vulcanization, so as to take into account the load-bearing stability, deformation buffering performance, tread performance and batch manufacturing consistency of high load-bearing solid tires. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention provides a high-load-bearing layered composite solid tire and its manufacturing method. By rationally configuring the material system and performance relationship of the base rubber layer, intermediate rubber layer, and tread rubber layer, the intermediate rubber layer maintains a constant elongation performance that is compatible with high load deformation while having relatively low hardness, thus balancing load buffering and deformation constraint. Furthermore, by controlling the molding and processing of each rubber layer and the tread edge, as well as the subsequent vulcanization process, the consistency of the tire blank molding and vulcanization process is improved.

[0011] One of the technical solutions adopted by this invention to solve its technical problem is:

[0012] A high load-bearing layered composite solid tire includes a base rubber layer, an intermediate rubber layer, and a tread rubber layer arranged sequentially from the inside to the outside. Each rubber layer is based on 100 parts of the main rubber by mass, wherein the total mass of each rubber component in the main rubber is 100 parts, and the mass of the remaining compound components is relative to the 100 parts of the main rubber.

[0013] The main rubber component of the base adhesive layer is composed of 40-80 parts of natural rubber, 10-30 parts of butadiene rubber and 10-30 parts of styrene-butadiene rubber. The compounding components of the base adhesive layer include 50-70 parts of carbon black N220 and 5-15 parts of tall oil modified phenolic reinforcing resin.

[0014] The main rubber component of the intermediate rubber layer consists of 60-80 parts of natural rubber and 20-40 parts of butadiene rubber, and the compounding components of the intermediate rubber layer include 15-30 parts of reclaimed rubber and 45-65 parts of carbon black N660.

[0015] The main rubber component of the tread layer consists of 50-80 parts of natural rubber, 10-20 parts of butadiene rubber, and 10-30 parts of styrene-butadiene rubber. The compound components of the tread layer include 15-30 parts of reclaimed rubber, 30-60 parts of carbon black N220, and 5-30 parts of carbon black N330.

[0016] The Shore A hardness of the intermediate rubber layer is lower than that of the base rubber layer and the tread rubber layer, and the 300% constant elongation stress of the intermediate rubber layer is not lower than that of the 300% constant elongation stress of the base rubber layer; the tensile strength of the intermediate rubber layer is greater than that of the base rubber layer and less than that of the tread rubber layer.

[0017] The high-load-bearing layered composite solid tire of this invention employs different main rubber systems and compound component systems for its base rubber layer, intermediate rubber layer, and tread rubber layer. Specifically, while the hardness of the intermediate rubber layer is lower than that of the base rubber layer and tread rubber layer, its 300% constant elongation stress remains no lower than that of the base rubber layer. This ensures that the intermediate rubber layer does not simply become a low-stiffness layer by reducing hardness, but rather maintains a constant elongation performance under specified elongation conditions while possessing lower hardness, thus adapting to the stress and deformation requirements of the intermediate rubber layer located between the base rubber layer and the tread rubber layer.

[0018] Furthermore, relative to 100 parts by weight of the base rubber layer, the compounding components of the base rubber layer further include 4-7 parts of zinc oxide, 1.5-2.5 parts of stearic acid, 0.5-2 parts of antioxidant 4020, 0.5-2 parts of antioxidant RD, 1-2.5 parts of heat stabilizer TCA-80, 1.8-2.5 parts of sulfur powder, 0.8-2 parts of vulcanization accelerator NOBS, and 1-2.5 parts of vulcanization accelerator HMTA.

[0019] Furthermore, relative to 100 parts by weight of the main rubber of the intermediate rubber layer, the compounding components of the intermediate rubber layer also include 4 to 7 parts of zinc oxide, 1.5 to 2.5 parts of stearic acid, 0.5 to 2.5 parts of antioxidant RD, 0.5 to 2.5 parts of heat stabilizer TCA-80, and 1.8 to 3 parts of sulfur powder.

[0020] Furthermore, relative to 100 parts by weight of the main rubber of the tread layer, the compounding components of the tread layer also include 4-7 parts of zinc oxide, 1.5-2.5 parts of stearic acid, 0.5-2.5 parts of antioxidant 4010NA or antioxidant 4020, 0.5-2.5 parts of antioxidant RD, 0.2-0.6 parts of scorch inhibitor CTP, 1.8-2.5 parts of sulfur powder, and 0.8-2 parts of vulcanization accelerator NOBS.

[0021] Further, in one specific embodiment, the main rubber of the base adhesive layer is composed of 65 parts of natural rubber, 25 parts of butadiene rubber, and 10 parts of styrene-butadiene rubber; the compounding components of the base adhesive layer include 62 parts of carbon black N220, 14 parts of tall oil modified phenolic reinforcing resin, 5.5 parts of zinc oxide, 1.9 parts of stearic acid, 1.7 parts of antioxidant 4020, 1.8 parts of antioxidant RD, 2.1 parts of heat stabilizer TCA-80, 2.2 parts of sulfur powder, 1.6 parts of vulcanization accelerator NOBS, and 2.2 parts of vulcanization accelerator HMTA.

[0022] The main rubber component of the intermediate rubber layer is composed of 70 parts of natural rubber and 30 parts of butadiene rubber; the compounding components of the intermediate rubber layer include 25 parts of reclaimed rubber, 56 parts of carbon black N660, 5.0 parts of zinc oxide, 2.0 parts of stearic acid, 2.5 parts of antioxidant RD, 1.8 parts of heat stabilizer TCA-80, and 2.5 parts of sulfur powder.

[0023] The main rubber component of the tread layer consists of 65 parts natural rubber, 15 parts butadiene rubber, and 20 parts styrene-butadiene rubber; the compounding components of the tread layer include 15 parts reclaimed rubber, 45 parts carbon black N220, 25 parts carbon black N330, 4.8 parts zinc oxide, 2.5 parts stearic acid, 1.5 parts antioxidant 4010NA or antioxidant 4020, 1.5 parts antioxidant RD, 0.3 parts scorch inhibitor CTP, 2.1 parts sulfur powder, and 1.8 parts vulcanization accelerator NOBS.

[0024] One of the technical solutions adopted by the present invention to further solve its technical problem is:

[0025] The preparation method of high load-bearing layered composite solid tire includes the following steps:

[0026] S1. Rubber layer forming: Fix the inner stop ring on the forming drum, wrap the base rubber layer after plasticizing and passing through the open mill rolls around the outside of the inner stop ring to form the base rubber layer, and then wrap the intermediate rubber layer after plasticizing and passing through the open mill rolls around the outside of the base rubber layer to form the intermediate rubber layer.

[0027] S2. Tread rubber layer splitting and forming: The tread rubber layer of the same plasticizing process is first rolled through the open mill and then divided into a first tread rubber layer and a second tread rubber layer. The first tread rubber layer is wound around the outside of the middle rubber layer to form the main tread. The second tread rubber layer is rolled through the open mill 2 to 3 times after the first roll, and then wound around both sides of the main tread to form edge binding rubber, thus obtaining the tire blank.

[0028] The first and second tread rubber layers are derived from the same plasticizing process and undergo initial rolling together, ensuring that the main tread and the edge rubber have the same rubber compound formula and pre-processing basis. The second tread rubber layer undergoes further rolling after splitting and is then used for edge forming on both sides of the main tread axis, thus enabling the same tread rubber layer material to meet the different forming requirements of the main tread and the edge parts.

[0029] S3. Vulcanization molding: From the completion of the edge wrapping rubber and obtaining the tire blank to the time of placing the tire blank into the vulcanization mold, the tire blank is vulcanized. After vulcanization, the tire blank is demolded to obtain the vulcanized rubber ring, and the vulcanized rubber ring is pressed with the matching steel ring and retainer ring to obtain the high load-bearing layered composite solid tire.

[0030] By controlling the dwell time of the tire blank from the completion of edge wrapping to the vulcanization process, the tire blank after multi-layer winding can enter the subsequent vulcanization process within a specified time. This helps to reduce the changes in the state of the rubber layer caused by the long dwell time of the tire blank and improve the consistency of the forming and vulcanization process of different batches of tire blanks.

[0031] Furthermore, the roll gap of the open mill is 5-6 mm; the plasticizing temperature of the base rubber layer is not higher than 115℃, and the plasticized base rubber layer is passed through the open mill 2-3 times; the plasticizing temperature of the intermediate rubber layer is not higher than 120℃, and the plasticized intermediate rubber layer is passed through the open mill 2-3 times; the plasticizing temperature of the tread rubber layer is not higher than 120℃, and the tread rubber layer is divided into the first part of the tread rubber layer and the second part of the tread rubber layer after the first passing through the open mill 2-3 times; thus, the plasticizing temperature and the number of passing through the rolls are controlled according to the composition of the rubber compound of different rubber layers and the subsequent molding requirements.

[0032] Furthermore, the open mill is equipped with two baffles. Before the base rubber layer is formed, the initial distance between the two baffles is set to be 200 mm larger than the preset forming width of the base rubber layer, and one baffle is aligned with one axial end of the inner stop ring. After the base rubber layer reaches the preset forming width after passing through the rollers of the open mill, the position of the other baffle is adjusted so that the two baffles are respectively aligned with the two axial ends of the inner stop ring.

[0033] Before forming the edge-sealing adhesive, the distance between the two baffles is adjusted according to the forming width of the edge-sealing adhesive, and the two baffles are symmetrically arranged with respect to the axial center of the inner stop ring. Thus, the forming width and axial position of the adhesive are controlled by the two baffles at different stages of the base adhesive layer forming and the edge-sealing adhesive forming.

[0034] Furthermore, before the tire blank is placed into the mold, the edge binding adhesive on both sides of the tire blank is applied flat and fixed, and the actual net weight of the tire blank is measured. If there is a difference between the actual net weight of the tire blank and the preset net weight of the corresponding specification, the weight of the tire blank is adjusted so that the actual net weight reaches the preset net weight before the tire blank is placed into the mold. By checking and adjusting the edge binding condition and net weight of the tire blank before mold placement, it is beneficial to reduce the differences in molding state between tire blanks.

[0035] Furthermore, during vulcanization, the set temperature of the mold heating equipment is set to 150℃. After the upper and lower hot plates of the mold reach a constant temperature, the actual detected temperature of the upper and lower hot plates is maintained at 140-148℃, and the vulcanization pressure is 18-20 MPa. For the first mold of tires in the same batch, the mold is preheated for no less than 4 hours before the tire blank is placed into the mold. By preheating the mold for the initial thermal state of the first mold of tires, it is beneficial to reduce the difference in vulcanization conditions between the first mold and subsequent molds due to the different thermal states of the molds.

[0036] Compared with the prior art, the high load-bearing layered composite solid tire and its manufacturing method of the present invention have at least the following beneficial effects:

[0037] 1. A differentiated three-layer material system is formed. The base layer uses natural rubber, butadiene rubber, and styrene-butadiene rubber as the main components, combined with carbon black N220 and tall oil modified phenolic reinforcing resin; the middle layer uses natural rubber and butadiene rubber as the main components, combined with reclaimed rubber and carbon black N660; the tread layer uses natural rubber, butadiene rubber, and styrene-butadiene rubber as the main components, combined with reclaimed rubber and N220 / N330 carbon black system, so that the three layers can form corresponding material properties according to their different positions in the radial direction of the solid tire.

[0038] 2. The intermediate rubber layer balances low hardness with good elongation performance. The Shore A hardness of the intermediate rubber layer is lower than that of the base rubber layer and the tread rubber layer. At the same time, the 300% elongation stress of the intermediate rubber layer is not lower than that of the base rubber layer. Thus, the intermediate rubber layer can maintain low hardness and deformation compliance while still having high elongation performance under specified elongation.

[0039] 3. The three rubber layers form a differentiated tensile strength configuration. The tensile strength of the middle rubber layer is higher than that of the base rubber layer, and the tensile strength of the tread rubber layer is even higher than that of the middle rubber layer. This allows the middle rubber layer to maintain a lower Shore A hardness without a corresponding reduction in tensile strength, and further endows the tread rubber layer with tensile properties adapted to its ground contact working position.

[0040] 4. The method for preparing the high load-bearing layered composite solid tire of the present invention involves plasticizing, rolling and winding each rubber layer separately, and forming the tread rubber layer by diversion and further processing to form the main tread and side edging. After the tire blank is sorted, it is placed into the mold for vulcanization. This method is beneficial to take into account the performance requirements of different working areas of the solid tire and improve the consistency of the layered molding and vulcanization process.

[0041] 5. The main tread and edge rubber of the tread layer are processed separately in the same tread layer. The main tread and edge rubber are plasticized in the same time and the tread layer is rolled together for the first time. On this basis, a part of it is directly used for the main tread, and the other part is rolled again and used for the edge on both sides. This makes the main tread and edge rubber have the same formula and the same pre-processing basis. At the same time, different subsequent processing processes are used to adapt to the different molding requirements of the two.

[0042] 6. Continuous control of the tire blank forming and vulcanization process is implemented. By limiting the dwell time from the completion of edge wrapping to the vulcanization in the mold, and by combining edge wrapping and finishing of the tire blank, net tire blank weight inspection, and compensation for the thermal state of the first mold vulcanization, it is beneficial to reduce product fluctuations caused by differences in the condition of the tire blank and the initial thermal state of the mold during production, and improve the consistency of the forming and vulcanization process. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the high load-bearing layered composite solid tire of the present invention;

[0044] Figure 2 This is a schematic diagram of the process flow for the preparation method of the high load-bearing layered composite solid tire of the present invention;

[0045] Wherein: 1-base rubber layer; 2-intermediate rubber layer; 3-tread rubber layer; 4-steel wire ring; 5-rim. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Unless otherwise stated, the amounts of each component in this specification are by weight. The base rubber layer, intermediate rubber layer, and tread rubber layer are each based on 100 parts of the main rubber, wherein the total weight of all rubber components included in the main rubber is 100 parts, and the amounts of the remaining compound components are all relative to 100 parts of the main rubber of the corresponding rubber layer.

[0047] In this specification, natural rubber refers to natural rubber, butadiene rubber refers to cis-butadiene rubber, and styrene-butadiene rubber refers to styrene-butadiene rubber; tall oil modified phenolic reinforcing resin is tall oil modified phenolic reinforcing resin HY-2001; antioxidant 4020 is N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, antioxidant 4010NA is N-isopropyl-N′-phenyl-p-phenylenediamine, antioxidant RD is 2,2,4-trimethyl-1,2-dihydroquinoline polymer, vulcanization accelerator NOBS is N-oxodiethylene-2-benzothiazole sulfenamide, HMTA is hexamethylenetetramine, scorch inhibitor CTP is N-cyclohexylthiophthalimide, and heat stabilizer TCA-80 is mainly a compound of sodium stearate and a small amount of potassium stearate.

[0048] I. Experiment on Formulation and Performance Testing of Base Adhesive Layer

[0049] The base layer of the high-load-bearing layered composite solid tire of this invention consists of natural rubber, butadiene rubber, and styrene-butadiene rubber 1502, with a total mass fraction of 100 parts. Zinc oxide, stearic acid, antioxidant 4020, antioxidant RD, carbon black N220, tall oil-modified phenolic reinforcing resin, heat stabilizer TCA-80, sulfur powder, vulcanization accelerator NOBS, and HMTA are added to the 100 parts of the base rubber.

[0050] Examples B1-B3 selected different proportions of the main rubber and the amounts of compounding components. All three base layer comparative examples used 100 parts of natural rubber as the main material, without employing the ternary main system of natural rubber, butadiene rubber, and styrene-butadiene rubber as in the examples, to verify the performance of the base layer material system under different specific formulation conditions. Secondly, comparative examples BC1-BC3 compared the overall formulation systems. Examples B1-B3 differed from the corresponding comparative examples BC1-BC3 not only in the main rubber system but also in some compounding components and their amounts. Therefore, the experimental results were used to evaluate the overall performance differences between the overall formulation systems of the examples and the corresponding control formulation systems, rather than attributing all performance changes to a single component.

[0051] The specific components and formulations of the base adhesive layer examples B1~B3 and the corresponding comparative examples BC1~BC3 are shown in Table 1 below.

[0052]

[0053] Vulcanized samples were prepared using the rubber compounds from Examples B1-B3 and the corresponding comparative examples BC1-BC3, respectively, and their material properties were tested according to the test methods used in the actual test records. The 300% elongation stress refers to the stress corresponding to the vulcanized rubber sample reaching a specified 300% elongation state. It is used to characterize the tensile stress response of the rubber compound under a specified maximum elongation state and does not necessarily indicate that the tire will undergo 300% working deformation during actual operation.

[0054]

[0055] The performance test results of the base adhesive layer are shown in Table 2. The Shore A hardness of the base adhesive layer in Examples B1 to B3 is maintained at 85 to 86 HA, which is similar to that of the corresponding proportions BC1 to BC3. However, the tensile strength and 300% constant elongation stress of Examples B1 to B3 are higher than those of the corresponding proportions, while the compression set and Akron abrasion are lower than those of the corresponding proportions.

[0056] Taking Example B1 as an example, its tensile strength increased from 12.3 MPa in Comparative Example BC1 to 14.7 MPa, and its 300% constant elongation stress increased from 8.1 MPa to 10.8 MPa; while the hardness was basically similar, the compression set decreased from 38% to 32%.

[0057] The above results indicate that, under the three specific formulation conditions verified, the load-bearing related properties exhibited by the overall formulation of the base layer are not obtained by simply increasing the Shore A hardness, but rather by maintaining a high hardness level while enabling the compound to have a high specified elongation stress response and low compression set. This performance configuration is adapted to the working position of the base layer, which bears the load transfer and dimensional stability.

[0058] II. Intermediate Adhesive Layer Formulation and Performance Testing Analysis Experiment

[0059] The main rubber component of the intermediate rubber layer of the high-load-bearing layered composite solid tire of this invention consists of natural rubber and butadiene rubber, totaling 100 parts. Reclaimed rubber, zinc oxide, stearic acid, antioxidant, TCA-80, carbon black N660, and sulfur powder are further added to the 100 parts of the main rubber. The comparative examples of the intermediate rubber layer all use 100 parts of natural rubber as the main material, without adding butadiene rubber, and the compounding components and their amounts are adjusted accordingly. The component ratios of Examples M1-M3 and Comparative Examples MC1-MC3 for the intermediate rubber layer performance analysis are shown in Table 3 below. The experimental results are used to evaluate the overall performance difference between the overall formulation system of the examples and the corresponding control formulation system, without attributing all performance changes to a single component.

[0060]

[0061] Unlike the base layer, the intermediate layer does not use a ternary rubber system composed of natural rubber, butadiene rubber, and styrene-butadiene rubber. Instead, it uses a binary rubber system composed of natural rubber and butadiene rubber, further combined with reclaimed rubber and carbon black N660. The design purpose of this material system is not simply to obtain lower hardness, but to maintain the elongation, tensile strength, and elastic recovery properties suitable for the working conditions of the intermediate layer while achieving lower hardness.

[0062] Referring to Table 4, which shows the performance test results of the intermediate rubber layers of high-load-bearing layered composite solid tires with different formulations in Examples M1-M3 of the present invention, and the intermediate rubber layers of comparative examples MC1-MC3 with corresponding adjustments to the main rubber composition and auxiliary material ratios, the hardness of the intermediate rubber layers in Examples M1-M3 is 65HA, 65HA, and 66HA, respectively, all lower than that of the corresponding comparative examples (66HA, 66HA, and 67HA). However, with the reduced hardness, the tensile strength, 300% elongation stress, and impact rebound of the three examples are all higher than those of the corresponding comparative examples.

[0063]

[0064] Taking Example M1 as an example, the hardness of the intermediate adhesive layer decreased from 66HA in Comparative Example MC1 to 65HA, while the tensile strength increased from 12.8MPa to 16.3MPa, the 300% constant elongation stress increased from 8.5MPa to 10.85MPa, and the impact rebound increased from 30 to 36.

[0065] Therefore, the performance changes exhibited by the intermediate rubber layer examples M1-M3 cannot be explained by increasing the hardness to obtain mechanical properties. The overall combination of the natural rubber / butadiene rubber binary system with reclaimed rubber and carbon black N660 allows the intermediate rubber layer to maintain corresponding tensile, elongation at a constant elongation, and elastic recovery properties even under lower Shore A hardness conditions.

[0066] This performance relationship is of practical significance for the intermediate rubber layer. The intermediate rubber layer is located between the high-hardness base rubber layer and the outer tread rubber layer. If deformation capacity is obtained solely by reducing the rigidity of the rubber compound, it may lack the necessary mechanical restraint under large deformation conditions. In this embodiment, the intermediate rubber layer maintains a low hardness while its 300% constant elongation stress is not correspondingly reduced, thus forming a material performance configuration that differs from that of a simple soft cushioning rubber.

[0067] III. Experiment on Tread Rubber Formulation and Performance Testing

[0068] The main rubber of the tread layer of the high load-bearing layered composite solid tire of the present invention is composed of natural rubber, butadiene rubber and styrene-butadiene rubber, totaling 100 parts; in addition to the 100 parts of the main rubber, reclaimed rubber, zinc oxide, stearic acid, antioxidant, carbon black N220, carbon black N330, CTP, sulfur powder and vulcanization accelerator NOBS are further configured.

[0069] The comparative examples of tread rubber layers all used 100 parts of natural rubber as the main material, without adding butadiene rubber or styrene-butadiene rubber. The formulation components and their amounts were adjusted accordingly. The component ratios of Examples T1-T3 and Comparative Examples TC1-TC3 for tread rubber layer performance analysis are shown in Table 5 below. The test results are used to evaluate the overall performance difference between the overall formulation system of the examples and the corresponding control formulation system, without attributing all performance changes to a single component.

[0070]

[0071] The tread rubber layer uses a composite carbon black reinforcement system composed of N220 and N330, and retains recycled rubber to meet the comprehensive requirements of the tread area for strength, tear and abrasion resistance.

[0072]

[0073] In Examples T1-T3, the tensile strength, 300% constant elongation stress, elongation at break, and tear strength of the three different tread rubber layers were all higher than those of the corresponding ratios TC1-TC3, while the Akron abrasion values ​​were all lower than those of the corresponding ratios.

[0074] In this study, both Example T1 and Comparative Example TC1 had a hardness of 68HA. However, the tear strength of Example T1 increased from 52.54 kN / m to 73.23 kN / m, while the Akron abrasion decreased from 0.45 cm³ / 1.61 km to 0.35 cm³ / 1.61 km. This demonstrates that significant differences in tear and abrasion performance can still be observed under the same hardness conditions. This indicates that the performance exhibited by the tread rubber layer is not solely due to increased hardness, but rather corresponds to the overall configuration of its main rubber system, recycled materials, and the N220 / N330 composite reinforcement system.

[0075] Example 1

[0076] like Figure 1 As shown, the high-load-bearing layered composite solid tire of this embodiment includes a base rubber layer 1, an intermediate rubber layer 2, and a tread rubber layer 3 arranged sequentially from the inside out. The base rubber layer 1 is located on the side close to the rim 5 and is connected and positioned to the rim 5 by a steel wire ring 4; the intermediate rubber layer 2 is located between the base rubber layer 1 and the tread rubber layer 3; the tread rubber layer 3 constitutes the outer peripheral working area of ​​the tire.

[0077] By mass, each adhesive layer is based on 100 parts of the main rubber, wherein the total mass of each rubber component in the main rubber is 100 parts, and the mass of the remaining compound components is relative to the 100 parts of the main rubber.

[0078] The base layer's main rubber component consists of 50 parts natural rubber, 25 parts butadiene rubber, and 25 parts styrene-butadiene rubber. The base layer's compounding components include 60 parts carbon black N220, 10 parts tall oil-modified phenolic reinforcing resin, 5 parts zinc oxide, 2.5 parts stearic acid, 1 part antioxidant 4020, 2 parts antioxidant RD, 2 parts heat stabilizer TCA-80, 2.2 parts sulfur powder, 1.1 parts vulcanization accelerator NOBS, and 2.1 parts vulcanization accelerator HMTA.

[0079] The main rubber component of the intermediate rubber layer is composed of 60 parts of natural rubber and 40 parts of butadiene rubber. The compounding components of the intermediate rubber layer include 23 parts of reclaimed rubber, 52 parts of carbon black N660, 5 parts of zinc oxide, 2.5 parts of stearic acid, 1 part of antioxidant RD, 1.2 parts of heat stabilizer TCA-80, and 2.2 parts of sulfur powder.

[0080] The main rubber component of the tread layer is composed of 80 parts natural rubber, 10 parts butadiene rubber, and 10 parts styrene-butadiene rubber. The compound components of the tread layer include 18 parts reclaimed rubber, 50 parts carbon black N220 and 10 parts carbon black N330, 5 parts zinc oxide, 2.2 parts stearic acid, 1.5 parts antioxidant 4010NA or antioxidant 4020, 1.5 parts antioxidant RD, 0.4 parts scorch inhibitor CTP, 1.9 parts sulfur powder, and 1.2 parts vulcanization accelerator NOBS.

[0081]

[0082] The base rubber layer 1, intermediate rubber layer 2, and tread rubber layer 3 do not use the same rubber compound formulation. Instead, they are designed with separate main rubber systems and compounding systems based on their different working positions within the solid tire. The base rubber layer is mainly used to bear the load transmitted from the tire carcass to the rim side and maintain the tire's dimensional stability. The intermediate rubber layer, located between the base rubber layer and the tread rubber layer, needs to allow for a certain amount of elastic deformation while avoiding excessive softening that could lead to a loss of necessary mechanical restraint under large deformation. The tread rubber layer directly bears ground friction, localized impacts, and shearing forces, requiring a balance of strength, tear resistance, and abrasion resistance.

[0083] This embodiment specifically configures the material system of the intermediate rubber layer so that it does not merely form a soft buffer zone by reducing its hardness, but rather maintains a stress at a constant elongation of no less than 300% of that of the base rubber layer, even when its Shore A hardness is lower than that of the base rubber layer and the tread rubber layer. Thus, the lower hardness of the intermediate rubber layer complements its constant elongation performance under specified elongation conditions, enabling it to meet the deformation transfer requirements between the base rubber layer and the tread rubber layer.

[0084] Example 2

[0085] Compared with Example 1, the high load-bearing layered composite solid tire of this example includes a base rubber layer 1, an intermediate rubber layer 2 and a tread rubber layer 3 arranged sequentially from the inside to the outside. The formulations of the base rubber layer 1, the intermediate rubber layer 2 and the tread rubber layer 3 all adopt the raw material composition formulations corresponding to the base rubber layer, the intermediate rubber layer and the tread rubber layer shown in Example B2 in Table 1, Example M2 in Table 3 and Example T2 in Table 5. The specific formulations are shown in Table 8 below.

[0086]

[0087] Example 3

[0088] Compared with Example 1, the high load-bearing layered composite solid tire of this example includes a base rubber layer 1, an intermediate rubber layer 2 and a tread rubber layer 3 arranged sequentially from the inside to the outside. The formulations of the base rubber layer 1, the intermediate rubber layer 2 and the tread rubber layer 3 are all based on the raw material composition formulations of the base rubber layer, the intermediate rubber layer and the tread rubber layer shown in Example B3 in Table 1, Example M3 in Table 3 and Example T3 in Table 5. The specific formulations are shown in Table 9 below.

[0089]

[0090] Solid tire comparison example A

[0091] The solid tire of this comparative example includes a base rubber layer 1, an intermediate rubber layer 2, and a tread rubber layer 3 arranged sequentially from the inside out. The formulations of the base rubber layer 1, the intermediate rubber layer 2, and the tread rubber layer 3 are based on the raw material composition formulations of the base rubber layer, the intermediate rubber layer, and the tread rubber layer shown in Comparative Example BC3 in Table 1, Comparative Example MC3 in Table 3, and Comparative Example TC3 in Table 5, as detailed in Table 10 below.

[0092]

[0093] Solid tire comparison example B

[0094] The solid tire of this comparative example includes a base rubber layer 1, an intermediate rubber layer 2, and a tread rubber layer 3 arranged sequentially from the inside to the outside. The formulations of the base rubber layer 1, the intermediate rubber layer 2, and the tread rubber layer 3 are respectively based on the raw material composition formulations of the base rubber layer, the intermediate rubber layer, and the tread rubber layer shown in Example B3 in Table 1, Comparative Example MC3 in Table 3, and Example T3 in Table 5, as shown in Table 11 below.

[0095]

[0096] Solid tire comparison C

[0097] The solid tire of this comparative example includes a base rubber layer 1, an intermediate rubber layer 2, and a tread rubber layer 3 arranged sequentially from the inside to the outside. The formulations of the base rubber layer 1, the intermediate rubber layer 2, and the tread rubber layer 3 are respectively based on the raw material composition formulations of the base rubber layer, the intermediate rubber layer, and the tread rubber layer shown in Example B3 in Table 1, Example M3 in Table 3, and Comparative Example TC3 in Table 5, as shown in Table 12 below.

[0098]

[0099] Solid tire comparison scale D

[0100] The solid tire of this comparative example includes a base rubber layer 1, an intermediate rubber layer 2, and a tread rubber layer 3 arranged sequentially from the inside to the outside. The formulations of the base rubber layer 1, the intermediate rubber layer 2, and the tread rubber layer 3 are respectively composed of the raw materials corresponding to the base rubber layer, the intermediate rubber layer, and the tread rubber layer shown in Comparative Example BC3 in Table 1, Example M3 in Table 3, and Example T3 in Table 5, as shown in Table 13 below.

[0101]

[0102] 1) Performance analysis experiment of the three rubber layers of a high-load-bearing layered composite solid tire

[0103] To further illustrate the performance relationship of the three rubber layers—base layer 1, intermediate layer 2, and tread layer 3—in the same layered solid tire, the Shore A hardness, 300% tensile stress, and tensile strength of each rubber layer in the high load-bearing layered solid tires of Examples 1-3 above were tested and compared.

[0104]

[0105] Referring to Table 14, the performance test data of the three rubber layers of the solid tires in Examples 1-3 all exhibit the same performance relationship:

[0106] (1) The Shore A hardness of the intermediate rubber layer is lower than that of the base rubber layer and the tread rubber layer;

[0107] (2) The 300% constant tensile stress of the intermediate adhesive layer shall not be lower than the 300% constant tensile stress of the corresponding base adhesive layer;

[0108] (3) The tensile strength increases sequentially from the base rubber layer, the middle rubber layer to the tread rubber layer.

[0109] The data above shows that although the intermediate rubber layer has the lowest Shore A hardness among the three layers, its 300% elongation stress is not lower than that of the base rubber layer, and its tensile strength is also higher. Therefore, the intermediate rubber layer exhibits a performance profile that combines lower hardness with higher elongation at a given elongation, rather than simply placing a low-strength soft layer between the base and tread layers. On the other hand, the tread layer has a higher tensile strength than the intermediate rubber layer and possesses corresponding tear and abrasion resistance. Thus, the three rubber layers form different but complementary performance emphases in the same radial direction of the tire. It should be noted that the above performance relationships are the result of the combined effects of different main rubber systems and corresponding compounding systems, and cannot be attributed entirely to a single raw material. The examples and comparative examples are comparisons of the overall formulation system; therefore, their test results are used to evaluate the performance differences of the overall material system.

[0110] 2) Comparative Analysis Experiment of Overall Performance of Solid Tires

[0111] To further evaluate the load-bearing deformation performance of the actual solid tire formed by the combination of the above three-layer material systems, and to investigate the impact of changes in the base rubber layer, intermediate rubber layer, and tread rubber layer material systems on the overall tire load-bearing deformation performance, Example 3 and Comparative Examples A, B, C, and D were set up for comparative tire performance tests. In Comparative Examples B to D, a single-layer replacement method was used. While the other two rubber layers remained completely identical to those in Example 3, the intermediate rubber layer, tread rubber layer, and base rubber layer were replaced with the corresponding control rubber systems, ensuring that only one rubber layer material system changed between Example 3 and each single-layer replacement comparative example. This allowed for the examination of the correspondence between the changes in the corresponding rubber layer material system and the overall tire load-bearing deformation performance, and further evaluation of the overall matching relationship among the three rubber layer material systems.

[0112] Except for the aforementioned differences in the rubber layer material system, all schemes used the same tire specifications and the same tire preparation and testing conditions. The test tire specification was 385 / 65-24, the maximum test load was 10500 kg, corresponding to a static vertical load of approximately 102.97 kN. The test speed was 10 km / h, the continuous running time was 3 hours, and the ambient temperature was 24–27.6℃. The mold heating equipment for this tire specification was set to a temperature of 135℃, the baseline vulcanization time for a normal production mold was 6.5 hours, and the actual measured temperature after the upper and lower hot plates of the mold were kept at a constant temperature was 122–128℃. The test results are shown in Table 15 below.

[0113]

[0114] As shown in Table 15, under the same tire specifications and maximum test load conditions, the static full-load radial deformation of the high-load-bearing plywood composite solid tire in Example 3 is 28.9 mm, compared to 34.2 mm in Comparative Example A, a reduction of approximately 15.5%. The radial deformation of the high-load-bearing plywood composite solid tire in Example 3 under 15 days of continuous load is 10.2 mm, compared to 16.6 mm in Comparative Example A, a reduction of approximately 38.6%. Based on the ratio of the static vertical load to the static full-load radial deformation, the equivalent radial stiffness of the high-load-bearing plywood composite solid tire in Example 3 under the specified static load is approximately 3.56 kN / mm, higher than the 3.01 kN / mm in Comparative Example A.

[0115] The above results show that, under the same high load conditions, when all three rubber layers of this application use the aforementioned material system, the radial deformation under long-term continuous load can be reduced while static radial deformation is decreased, exhibiting better load-bearing stability and dimensional retention. Furthermore, single-layer replacement tests show that in Comparative Examples B to D, only one rubber layer was replaced with the control conventional rubber system, while the other two rubber layers retained the material system of this application. However, the static full-load radial deformation and long-term continuous load radial deformation of all three schemes increased compared to Example 3. Specifically, in Comparative Example B, after only the middle rubber layer was replaced, the static full-load radial deformation increased from 28.9 mm to 30.1 mm, and the long-term continuous load radial deformation increased from 10.2 mm to 12.5 mm; this indicates that the middle rubber layer is not merely a simple buffer layer, and the matching relationship between its material system and the base rubber layer and tread rubber layer affects the overall tire load-bearing deformation performance. After Comparative Examples C and D replaced the tread rubber layer and the base rubber layer respectively, the overall tire load-bearing deformation performance also decreased, further illustrating that the base rubber layer, intermediate rubber layer and tread rubber layer of this application are not simply superimposed, but rather form an overall matching relationship through the properties of different rubber layer materials.

[0116] 3) Correspondence analysis between overall tire hardness and load-bearing deformation

[0117] The hardness of the three rubber layers of the five solid tire whole tire schemes in Example 3 and Comparative Examples A to D was further tested, and the results are shown in Table 16 below.

[0118]

[0119] As can be seen from Table 16, Example 3 and Comparative Examples A to D all satisfy the differential hardness relationship that the hardness of the base rubber layer is greater than that of the tread rubber layer and the hardness of the tread rubber layer is greater than that of the intermediate rubber layer, and the Shore A hardness of the corresponding layers in each scheme is generally close.

[0120] However, while maintaining the same hardness level relationship, there are still significant differences in the overall tire load-bearing deformation performance of each scheme. For example, in Example 3, the Shore A hardness of the base rubber layer, tread rubber layer, and intermediate rubber layer are 86HA, 70HA, and 66HA, respectively, with a static full-load radial deformation of 28.9 mm and a radial deformation of 10.2 mm under 15 days of continuous load. In contrast, the corresponding hardnesses of the base rubber layer, tread rubber layer, and intermediate rubber layer of the solid tire in Comparative Example A are 85HA, 69HA, and 67HA, respectively, which also satisfy the hardness relationship of "base rubber layer > tread rubber layer > intermediate rubber layer". However, its static full-load radial deformation increases to 34.2 mm, and its radial deformation under 15 days of continuous load increases to 16.6 mm.

[0121] Furthermore, compared with Example 3, Comparative Example B maintained the same hardness of 86HA and 70HA for the base rubber layer and tread rubber layer, respectively, while the hardness of the intermediate rubber layer only changed from 66HA to 67HA, and both maintained the same hardness level relationship. However, after replacing the intermediate rubber layer of Example 3 with the control intermediate rubber layer in Comparative Example B, the static full-load radial deformation increased from 28.9 mm to 30.1 mm, and the long-term continuous load radial deformation increased from 10.2 mm to 12.5 mm.

[0122] The above results indicate that the overall load-bearing deformation performance of a tire cannot be explained solely by the simple hardness arrangement of the base rubber layer (high hardness), the middle rubber layer (low hardness), and the tread rubber layer (medium hardness). The specific material system and performance matching relationship of the three rubber layers have a significant impact on the overall load-bearing performance of the tire.

[0123] Based on the test results in Tables 14-16, it can be seen that although the intermediate rubber layer of this application has a lower Shore A hardness, its 300% elongation stress is not lower than that of the corresponding base rubber layer, indicating that it still maintains a high tensile stress response under specified maximum elongation conditions even under lower hardness conditions. This material property shows a consistent correlation with the smaller load-bearing deformation exhibited in the whole tire test, indicating that the load-bearing deformation performance of the whole tire cannot be evaluated solely by the hardness of each rubber layer, but is also related to the specific material system and corresponding mechanical property configuration of different rubber layers.

[0124] Further considering the equivalent radial stiffness under specified static load, the base rubber layer hardness of Example 3 and Comparative Example B is 86 HA, and the tread rubber layer hardness is 70 HA. However, the hardness of the intermediate rubber layer in Example 3 is lower than that of Comparative Example B (66 HA < 67 HA). Nevertheless, the equivalent radial stiffness of Example 3 under specified static load is approximately 3.56 kN / mm, higher than the approximately 3.42 kN / mm of Comparative Example B, while the radial deformation under long-term continuous load decreases from 12.5 mm to 10.2 mm. This further illustrates that this application does not increase the overall tire support capacity by increasing the hardness of the intermediate rubber layer, but rather maintains the flexibility of the intermediate rubber layer while maintaining the tensile stress response under specified maximum elongation, and achieves performance matching with other rubber layers.

[0125] Furthermore, the base layer employs a high-reinforcement system, maintaining high hardness while possessing good dimensional retention, which is beneficial for undertaking the main support role in the area near the rim. The tread layer, through the corresponding rubber body and reinforcement system configuration, meets the wear resistance and tear resistance requirements for direct contact with the ground. The base layer, intermediate layer, and tread layer each perform different functions, and form an overall composite structure through the matching of material properties.

[0126] The above comparison results show that when the base rubber layer, intermediate rubber layer, or tread rubber layer of this application are replaced with corresponding conventional control rubber layers, the static full-load radial deformation and long-term continuous load radial deformation of the entire tire all increase to varying degrees. The lowest load deformation index is achieved when all three rubber layers use the material system of this application. Therefore, the technical effect of this application does not stem from changes in a single rubber layer or a single hardness parameter, but rather from the overall matching formed by the specific material system and performance relationship between the base rubber layer, intermediate rubber layer, and tread rubber layer.

[0127] Example 4

[0128] This embodiment provides a preferred preparation method for a high load-bearing layered composite solid tire, including three continuous stages: rubber layer forming, tread rubber splitting forming, and vulcanization forming. The base rubber layer, intermediate rubber layer, and tread rubber layer are formed into a layered structure according to a predetermined radial position. The processing state of the main tread, the side edging, and the tire blank when entering the vulcanization process is controlled accordingly.

[0129] S1, Adhesive layer molding

[0130] Prepare matching inner stop rings, forming drums, and vulcanizing molds according to the specifications of the solid tires to be produced. The inner stop ring is a steel wire ring 4 set in the inner circumference area of ​​the tire, which serves as the inner annular base during the molding of the base rubber layer. The inner stop ring is fixed to the forming drum.

[0131] In this embodiment, an open mill is used to process the rubber compound through the rollers. The roller gap of the open mill is set to 5-6 mm, and two baffles are provided to control the forming width of the rubber compound. Before the base rubber layer is formed, the initial distance between the two baffles is set to be 200 mm larger than the preset forming width of the base rubber layer, and one of the baffles is aligned with one axial end of the inner stop ring.

[0132] (1) Weigh the base adhesive layer according to the preset dosage, and put the base adhesive layer into the kneading equipment for plasticizing. The plasticizing temperature is controlled not higher than 115℃. After plasticizing, the base adhesive layer is passed through the open mill 2 to 3 times to gradually form a tape that meets the winding requirements. When the base adhesive layer reaches the preset forming width, adjust the position of the other baffle so that the two baffles are aligned with the two ends of the inner stop ring respectively. The preset forming width of the base adhesive layer matches the axial width of the inner stop ring, thereby determining the forming width of the base adhesive layer tape and its axial position relative to the inner stop ring. Then, the base adhesive layer after passing through the rollers is wound around the outside of the inner stop ring to form base adhesive layer 1.

[0133] (2) Weigh the intermediate rubber layer according to the preset dosage, put the intermediate rubber layer into the kneading equipment for plasticizing, and control the plasticizing temperature to not exceed 120℃. After plasticizing, the intermediate rubber layer is passed through the open mill 2 to 3 times, and then the intermediate rubber layer after passing through the rollers is continuously wound around the outside of the already formed base rubber layer 1 to form the intermediate rubber layer 2. The base rubber layer and the intermediate rubber layer adopt different main rubber systems and compound systems, and their processing performance and molding requirements are also different. Therefore, the corresponding upper limit of plasticizing temperature and the number of times of passing through the rollers are adopted respectively, so that the two rubber materials reach a state suitable for continuous molding before entering the winding process.

[0134] The base rubber layer first determines the width and axial position of the inner load-bearing area. The intermediate rubber layer then continuously forms outwards from this foundation, providing a stable basis for the subsequent split molding of the tread rubber layers. It should be noted that the different plasticizing temperatures and roll passes mentioned above are primarily used to adapt to the processing and molding requirements of different rubber compound systems. Their technical role should be understood in conjunction with the entire layered molding process, rather than considering a single temperature value or roll pass as an independent cause for improved overall tire load-bearing performance.

[0135] S2, Tread rubber layer split molding

[0136] Weigh the tread rubber layer according to the preset dosage, and put the tread rubber layer into the kneading equipment for plasticizing. The plasticizing temperature is controlled not to exceed 120℃. The tread rubber layer obtained in the same plasticizing process is sent to the open mill for the first rolling, and the first rolling is performed 2 to 3 times.

[0137] After the initial rolling, the tread rubber layer is divided into a first tread rubber layer and a second tread rubber layer. The first tread rubber layer is used to form the main tread, and the second tread rubber layer is used to form the edge rubber on both sides of the main tread axially. The first tread rubber layer is wrapped around the outside of the intermediate rubber layer 2 and continuously formed along the tire circumference to form the main tread.

[0138] The second tread layer, after undergoing the initial roll pass together with the first tread layer, is fed back into the open mill for another 2-3 roll passes. Before forming the edge binding rubber, the distance between the two baffles is adjusted according to the forming width of the edge binding rubber, and the two baffles are symmetrically positioned relative to the axial center of the inner stop ring. Subsequently, the second tread layer, after being rolled again, is wound around the two axial sides of the main tread to form the edge binding rubber on both sides, completing the tread area forming and obtaining the tire blank.

[0139] In this step, the main tread layer and the side edge rubber are not two independently prepared batches of tread rubber layers, but rather tread rubber layers from the same plasticizing process and jointly completed the initial roll pass. Therefore, the first part of the tread rubber layer and the second part of the tread rubber layer have the same formulation and common pre-processing state before splitting.

[0140] Meanwhile, the main tread and the side edge rubber have different requirements in terms of forming width, amount of rubber used, and winding position. The first part of the tread rubber layer directly forms the main tread after completing a common initial roll pass, while the second part of the tread rubber layer is used for the side edge after 2-3 additional roll passes on the basis of the same pre-processing. This allows the main tread and the edge rubber to be processed according to their respective subsequent forming positions while maintaining the same rubber source and pre-processing state.

[0141] Therefore, this step does not simply divide the tread rubber layer into two parts for use. Instead, it completes the forming of the main tread and the side edgings under a continuous process relationship of same plasticizing → common initial rolling → splitting → differentiated subsequent processing → zoned forming. This process addresses the processing requirement that the main tread and side edging rubber should have the same material state, but the forming requirements are not exactly the same. It helps to reduce the differences in the state of the preceding rubber materials that may occur from the separate preparation of the main tread and side edging rubber, while enabling them to adapt to different subsequent forming requirements.

[0142] The aforementioned tread rubber layer splitting and differentiated subsequent processing constitute the main technological features of the tread forming stage in this embodiment, and should be understood as a continuous technical process.

[0143] S3, vulcanization molding

[0144] After wrapping the edges with adhesive, the tire blank is prepared before being placed into the mold.

[0145] First, apply and secure the adhesive tape to both sides of the tire blank. Then, remove the tire blank from the molding drum and weigh the actual net weight of the blank. Determine the corresponding preset net weight of the blank based on the specific specifications of the tire to be produced. If there is a difference between the actual net weight of the blank and the preset net weight for the corresponding specifications, adjust the weight of the tire blank according to the corresponding production process until the actual net weight reaches the preset net weight before placing it into the mold.

[0146] Through the above processing, different tire blanks entering the mold meet the molding requirements of their respective specifications in terms of edge wrapping and net tire blank weight, reducing the impact of differences in previous molding states on the vulcanization process. From the completion of edge wrapping on both sides of the second part of the tread rubber layer to form the tire blank, the dwell time of the tire blank until it is placed into the mold is controlled to not exceed 30 minutes.

[0147] After completing the aforementioned tire blank preparation and weight confirmation, the tire blank is placed into a vulcanization mold that matches its specifications for vulcanization. During vulcanization, the set temperature of the mold heating equipment is set to 150℃. After the upper and lower hot plates of the mold reach a constant temperature, the actual detected temperature of the upper and lower hot plates is maintained at 140-148℃, and the vulcanization pressure is 18-20MPa. The specific vulcanization time is determined according to the vulcanization process of the corresponding tire specifications.

[0148] For the first batch of tires, the mold should be preheated for no less than 4 hours before the tire blank is put into the mold.

[0149] In continuous production, the dwell time between the completion of tire blank forming and its placement in the mold, as well as the initial thermal state of the molds corresponding to the first and subsequent molds, can affect the actual processing conditions experienced by each tire blank. This embodiment controls the time between the completion of the edge binding and its placement in the mold within a specified range, ensuring that different tire blanks have relatively consistent time conditions when transitioning from the forming process to the vulcanization process; for the first molded tire, preheating compensation is used to control its initial thermal state, which differs from that of subsequent continuous production molds.

[0150] Therefore, S3 does not only specify a set of vulcanization temperature and pressure parameters, but controls the process state before and after vulcanization from three aspects: the state of the tire blank before entering the mold, the time conditions from molding to entering the mold, and the thermal state of the first mold, so that the tire blank formed by the previous layer molding can enter the vulcanization stage under relatively consistent process conditions.

[0151] After vulcanization, the mold is opened, the vulcanized rubber ring is demolded, and excess material and tire hairs on the parting surface are removed. A matching steel rim and retainer ring are selected according to the tire specifications. The vulcanized rubber ring is pressed onto the steel rim, and the retainer ring is installed in the specified position, ultimately yielding the high-load-bearing layered composite solid tire.

[0152] This embodiment provides a preferred preparation method for the high load-bearing layered composite solid tire of the present invention.

[0153] The coordination relationship and technical effects of each step in the above preparation method are as follows:

[0154] In the above preparation method, S1 to S3 are not independent processing steps, but rather a continuous process centered around the rubber layer forming of the layered solid tire, the differentiated forming of the tread area, and the control of the vulcanization state of the tire blank.

[0155] In S1, the base rubber layer and the intermediate rubber layer are plasticized, rolled, and wound sequentially according to their respective rubber compound systems, so that the base rubber layer and the intermediate rubber layer are formed in a predetermined radial position, providing a stable layering basis for the subsequent tread rubber layer forming.

[0156] In S2, the main tread and the edge rubber are plasticized in the same batch and undergo their initial roll pass, ensuring they have the same rubber composition and pre-processing state. Based on this, the tread rubber layers are split, and the second part of the tread rubber layer, used to form the edge rubber, undergoes further roll pass 2-3 times before the edge binding is performed. Thus, while maintaining consistency in the source of the main tread and the edge rubber's rubber composition and pre-processing state, they can respectively adapt to the different forming requirements of continuous main tread winding and edge binding.

[0157] In S3, by confirming the edge wrapping status and net tire weight of the tire blank before it enters the mold, and controlling the dwell time from edge wrapping to vulcanization and the initial thermal state of the mold corresponding to the first tire, the tire blank that has completed layered winding enters the vulcanization stage under the corresponding process conditions, thereby reducing the process fluctuations caused by differences in molding status, dwell time and initial thermal state of the mold between different tire blanks.

[0158] Therefore, this embodiment, through the continuous coordination of S1 to S3, further coordinates the consistency and differentiated molding requirements of the rubber materials of the main tread and the edge rubber on the basis of completing the radial layering molding of the base rubber layer, intermediate rubber layer and tread rubber layer, and controls the process state of the tire blank when it enters the vulcanization stage from the molding stage, thereby improving the consistency of the layered solid tire molding and vulcanization process.

[0159] The above embodiments are used to illustrate the preferred technical solutions of the present invention, and are not intended to further limit the scope of protection. Those skilled in the art can make corresponding adjustments to the specific operating methods according to the specifications of solid tires, equipment conditions, and production requirements without departing from the technical concept of the present invention; such adjustments should be based on achieving the corresponding formulation composition of each rubber layer and its layered composite structure.

Claims

1. A high-load-bearing layered composite solid tire, characterized in that, The high load-bearing layered composite solid tire includes a base rubber layer, an intermediate rubber layer, and a tread rubber layer arranged sequentially from the inside to the outside. Each rubber layer is based on 100 parts of the main rubber by mass. The total mass of each rubber component in the main rubber is 100 parts, and the mass of the remaining compound components is relative to the 100 parts of the main rubber. The main rubber component of the base layer consists of 40-80 parts of natural rubber, 10-30 parts of butadiene rubber and 10-30 parts of styrene-butadiene rubber. The compounding components of the base layer include 50-70 parts of carbon black N220 and 5-15 parts of tall oil modified phenolic reinforcing resin. The main rubber component of the intermediate rubber layer is composed of 60-80 parts of natural rubber and 20-40 parts of butadiene rubber, and the compounding components of the intermediate rubber layer include 15-30 parts of reclaimed rubber and 45-65 parts of carbon black N660. The main rubber component of the tread rubber layer is composed of 50-80 parts of natural rubber, 10-20 parts of butadiene rubber and 10-30 parts of styrene-butadiene rubber. The compound components of the tread rubber layer include 15-30 parts of reclaimed rubber, 30-60 parts of carbon black N220 and 5-30 parts of carbon black N330. The Shore A hardness of the intermediate rubber layer is lower than that of the base rubber layer and the tread rubber layer, and the 300% constant elongation stress of the intermediate rubber layer is not lower than that of the 300% constant elongation stress of the base rubber layer; the tensile strength of the intermediate rubber layer is greater than that of the base rubber layer and less than that of the tread rubber layer.

2. The high-load-bearing layered composite solid tire according to claim 1, characterized in that, Relative to 100 parts by weight of the base rubber layer, the compounding components of the base rubber layer further include 4-7 parts of zinc oxide, 1.5-2.5 parts of stearic acid, 0.5-2 parts of antioxidant 4020, 0.5-2 parts of antioxidant RD, 1-2.5 parts of heat stabilizer TCA-80, 1.8-2.5 parts of sulfur powder, 0.8-2 parts of vulcanization accelerator NOBS, and 1-2.5 parts of vulcanization accelerator HMTA.

3. The high-load-bearing layered composite solid tire according to claim 1, characterized in that, Relative to 100 parts by weight of the main rubber of the intermediate rubber layer, the compounding components of the intermediate rubber layer further include 4 to 7 parts of zinc oxide, 1.5 to 2.5 parts of stearic acid, 0.5 to 2.5 parts of antioxidant RD, 0.5 to 2.5 parts of heat stabilizer TCA-80, and 1.8 to 3 parts of sulfur powder.

4. A high-load-bearing layered composite solid tire according to claim 1, characterized in that, Relative to 100 parts by weight of the main rubber of the tread layer, the compounding components of the tread layer further include 4-7 parts of zinc oxide, 1.5-2.5 parts of stearic acid, 0.5-2.5 parts of antioxidant 4010NA or antioxidant 4020, 0.5-2.5 parts of antioxidant RD, 0.2-0.6 parts of scorch inhibitor CTP, 1.8-2.5 parts of sulfur powder, and 0.8-2 parts of vulcanization accelerator NOBS.

5. A high-load-bearing layered composite solid tire according to claim 1, characterized in that, The formulations of the base rubber layer, intermediate rubber layer, and tread rubber layer of the solid tire are as follows: By mass, each adhesive layer is based on 100 parts of the main rubber, wherein the total mass of each rubber component in the main rubber is 100 parts, and the mass of the remaining compound components is relative to the 100 parts of the main rubber. The base layer's main rubber component is composed of 65 parts natural rubber, 25 parts butadiene rubber, and 10 parts styrene-butadiene rubber. The base layer's compounding components include 62 parts carbon black N220 and 14 parts tall oil-modified phenolic reinforcing resin, as well as 5.5 parts zinc oxide, 1.9 parts stearic acid, 1.7 parts antioxidant 4020, 1.8 parts antioxidant RD, 2.1 parts heat stabilizer TCA-80, 2.2 parts sulfur powder, 1.6 parts vulcanization accelerator NOBS, and 2.2 parts vulcanization accelerator HMTA. The main rubber component of the intermediate rubber layer is composed of 70 parts of natural rubber and 30 parts of butadiene rubber. The compounding components of the intermediate rubber layer include 25 parts of reclaimed rubber, 56 parts of carbon black N660, 5.0 parts of zinc oxide, 2.0 parts of stearic acid, 2.5 parts of antioxidant RD, 1.8 parts of heat stabilizer TCA-80, and 2.5 parts of sulfur powder. The main rubber component of the tread layer is composed of 65 parts natural rubber, 15 parts butadiene rubber, and 20 parts styrene-butadiene rubber. The compound components of the tread layer include 15 parts reclaimed rubber, 45 parts carbon black N220 and 25 parts carbon black N330, as well as 4.8 parts zinc oxide, 2.5 parts stearic acid, 1.5 parts antioxidant 4010NA or antioxidant 4020, 1.5 parts antioxidant RD, 0.3 parts scorch inhibitor CTP, 2.1 parts sulfur powder, and 1.8 parts vulcanization accelerator NOBS.

6. A method for preparing a high-load-bearing layered composite solid tire according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Glue layer forming: Fix the inner stop ring on the forming drum, wrap the base glue after plasticizing and passing through the open mill rolls around the outside of the inner stop ring to form a base glue layer, and then wrap the intermediate glue layer after plasticizing and passing through the open mill rolls around the outside of the base glue layer to form an intermediate glue layer. S2. Tread rubber layer splitting and forming: The tread rubber layer of the same plasticizing process is first rolled through the open mill and then divided into a first tread rubber layer and a second tread rubber layer. The first tread rubber layer is wound around the outside of the middle rubber layer to form the main tread. The second tread rubber layer is rolled through the open mill 2 to 3 times after the first rolling, and then wound around both sides of the main tread to form edge binding rubber, thus obtaining the tire blank. S3. Vulcanization molding: The tire blank is vulcanized; after vulcanization, it is demolded to obtain a vulcanized rubber ring, and the vulcanized rubber ring is pressed together with a matching steel ring and retaining ring to obtain the high load-bearing layered composite solid tire.

7. The method for preparing a high-load-bearing layered composite solid tire as described in claim 6, characterized in that, The roll gap of the open mill is 5-6 mm; The plasticizing temperature of the base rubber layer is not higher than 115℃, and the plasticized base rubber layer is passed through the open mill 2-3 times; The plasticizing temperature of the intermediate rubber layer is not higher than 120°C, and the plasticized intermediate rubber layer is passed through the open mill 2-3 times. The plasticizing temperature of the tread rubber layer is not higher than 120°C. After the tread rubber layer passes through the open mill 2-3 times for the first time, it is divided into the first part of the tread rubber layer and the second part of the tread rubber layer.

8. The method for preparing a high-load-bearing layered composite solid tire as described in claim 6, characterized in that, The open mill is equipped with two baffles. Before the base rubber layer is formed, the initial distance between the two baffles is set to be 200 mm larger than the preset forming width of the base rubber layer, and one of the baffles is aligned with one axial end of the inner stop ring. After the base rubber layer passes through the open mill rolls to reach the preset forming width, the position of the other baffle is adjusted so that the two baffles are respectively aligned with the two axial ends of the inner stop ring.

9. The method for preparing a high-load-bearing layered composite solid tire as described in claim 6, characterized in that, In S3, the time from when the edge-wrapping adhesive is completed in S2 and the tire blank is obtained until the tire blank is placed into the vulcanizing mold does not exceed 30 minutes; before the tire blank is placed into the mold, the edge-wrapping adhesive on both sides of the tire blank is flattened and fixed, and the actual net weight of the tire blank is weighed; when the actual net weight of the tire blank differs from the preset net weight of the corresponding specification, the weight of the tire blank is adjusted so that the actual net weight of the tire blank reaches the preset net weight before the tire blank is placed into the mold.

10. The method for preparing a high-load-bearing layered composite solid tire as described in claim 6, characterized in that, In S3, during vulcanization, the set temperature of the mold heating equipment is set to 150℃. After the upper and lower hot plates of the mold are kept at a constant temperature, the actual detection temperature of the upper and lower hot plates is kept at 140-148℃, and the vulcanization pressure is 18-20 MPa. For the first batch of tires, the mold is preheated for no less than 4 hours before the tire blank is put into the mold.

Images