A mold simulating the vulcanization process of a tire, a method for manufacturing the same, and an application thereof

Abstract

This invention provides a mold for simulating the tire vulcanization process, its preparation method, and its application. The mold is made of nylon fiber-reinforced phenolic resin. This invention uses phenolic resin as the matrix and nylon fiber as the reinforcement. Phenolic resin has excellent heat resistance and thermal insulation properties, but it is relatively brittle and its heat transfer coefficient is generally lower than that of rubber. Therefore, this invention uses nylon fiber, which has a higher heat transfer coefficient than rubber and good toughness, high strength, and strong compressive strength, to composite with phenolic resin. This makes the prepared composite material more closely resemble the heat transfer coefficient of rubber. The resulting mold has two-dimensional, double-sided heat transfer characteristics, ensuring that it more closely matches the actual vulcanization heat transfer process of the tire, greatly improving the accuracy of the mold in predicting tire vulcanization time.

Description

Technical Field

[0001] This invention belongs to the field of rubber industry technology, specifically relating to a mold for simulating the vulcanization process of tires, its preparation method and application. Background Technology

[0002] Rubber is a poor conductor of heat. For example, in thick rubber products like heavy-duty tires, when the tire surface reaches proper vulcanization, the center may still be under-vulcanized. Therefore, during tire manufacturing, ensuring proper vulcanization of the center is a primary consideration. To be on the safe side, in actual production, under suitable vulcanization conditions, the vulcanization time is often extended. However, under stable temperature control, extending the vulcanization time can lead to over-vulcanization, reducing tire quality and increasing energy consumption. Therefore, shortening the vulcanization time while ensuring complete vulcanization is crucial for energy conservation and extending tire lifespan. Currently, the thermocouple embedding method is generally used to determine the vulcanization time of new tire specifications. This involves placing thermocouples at weak points in the vulcanization process, and defining the time required for these weak points to reach a reasonable degree of vulcanization as the overall vulcanization time. However, embedding thermocouples throughout the entire tire is very costly for tire manufacturers. Therefore, there is an urgent need to establish a method in the laboratory that can equivalently simulate the tire vulcanization process.

[0003] Currently, laboratory-scale wire-embedded temperature measurement methods typically use stainless steel molds to manufacture tires. However, stainless steel molds are hexahedral heat transfer models with very high thermal conductivity, leading to inaccurate predictions of vulcanization times due to their short duration. The thickest part of a heavy-duty tire is generally along the central axis from the tread center to the airtight layer, which is a two-sided heat transfer model. Therefore, designing a two-sided heat transfer mold in the laboratory is a prerequisite for effectively simulating the tire vulcanization process. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a mold for simulating the vulcanization process of a tire, its preparation method, and its application. The mold is a double-sided heat transfer model, capable of accurately and equivalently simulating the vulcanization process of a tire and accurately predicting the vulcanization time.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a mold for simulating the vulcanization process of a tire, the mold being made of nylon fiber reinforced phenolic resin.

[0007] Preferably, the phenolic resin is a thermosetting phenolic resin.

[0008] Preferably, the mass ratio of the nylon fiber to the phenolic resin is (3-4):1.

[0009] Preferably, the thermal conductivity of the mold is 0.21 to 0.25 W / (m·K).

[0010] Secondly, the present invention provides a method for preparing a mold, comprising the following steps:

[0011] The product is obtained by impregnating nylon fiber products with a phenolic resin solution and then curing them.

[0012] Preferably, the nylon fiber product includes nylon curtain fabric.

[0013] Preferably, the solvent in the phenolic resin solution is industrial alcohol.

[0014] Preferably, the ratio of phenolic resin to solvent in the phenolic resin solution is 1 kg:(2-3) L.

[0015] Preferably, the immersion time is 15 to 40 minutes.

[0016] Preferably, the curing temperature is 130–200°C and the curing time is 20 min–3 h.

[0017] Thirdly, the present invention provides an application of the mold involved in the above technical solution in predicting tire vulcanization time.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] This invention provides a mold for simulating the vulcanization process of a tire. The mold is made of phenolic resin reinforced with nylon fibers. The mold uses phenolic resin as the matrix and nylon fibers as the reinforcement. Phenolic resin has excellent heat resistance and heat insulation properties, but it is brittle and its heat transfer coefficient is generally lower than that of rubber. Therefore, this invention uses nylon fibers, which have a higher heat transfer coefficient than rubber and good toughness, high strength, and strong compressive strength, to combine with phenolic resin. This makes the prepared composite material more closely match the heat transfer coefficient of rubber. The prepared mold has two-dimensional double-sided heat transfer characteristics, which can ensure that it more closely matches the actual vulcanization heat transfer process of the tire, greatly improving the accuracy of the mold for predicting the vulcanization time of the tire. Attached Figure Description

[0020] Figure 1 Macroscopic views of molds at different heights;

[0021] Figure 2 A is a distribution diagram of different temperature measuring points inside the mold;

[0022] Figure 2 B is Figure 2 Temperature rise curves at different temperature measurement points in Figure A;

[0023] Figure 3A is a distribution diagram of different temperature measuring points inside the mold;

[0024] Figure 3 B is Figure 3 Temperature rise curves at different temperature measurement points in Figure A;

[0025] Figure 4 This is a distribution diagram of multiple temperature measuring points within the simulated engineering tire and mold;

[0026] Figure 5 A comparison chart of the temperature measurement curves of the embedded wire in a simulated engineering tire and the temperature rise curve inside the mold at multiple identical temperature measurement points. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] In existing technologies, laboratory wire-embedded temperature measurement methods mostly use stainless steel molds. However, stainless steel molds are hexahedral heat transfer models with very high thermal conductivity, resulting in inaccurate predictions of tire vulcanization time due to excessively short readings. Therefore, this invention provides a mold for simulating the tire vulcanization process, made of nylon fiber-reinforced phenolic resin. In this invention, the phenolic resin can be any commercially available product, either thermosetting or thermoplastic. Thermosetting phenolic resin can cure freely upon heating, while thermoplastic phenolic resin requires a reaction with a curing agent (e.g., hexamethylenetetramine) to cure. The curing agent is typically one-tenth the amount of thermoplastic phenolic resin used. In some embodiments of this invention, thermosetting phenolic resin is preferred.

[0029] In this invention, the nylon fiber reinforced phenolic resin is obtained by compounding nylon fiber and phenolic resin. In some embodiments of this invention, the preferred mass ratio of nylon fiber to phenolic resin in the nylon fiber reinforced phenolic resin is (3-4):1, specifically 3:1, 3.2:1, 3.4:1, 3.6:1, 3.6:1, 3.8:1, or 4:1, etc. Other ratios within this range are also applicable and will not be elaborated here.

[0030] This invention uses phenolic resin as the matrix and nylon fiber as the reinforcement. Phenolic resin has excellent heat resistance and thermal insulation properties, but it is relatively brittle, and its heat transfer coefficient (0.02-0.03 W / (m·k)) is generally lower than that of rubber. The heat transfer coefficient of nylon fiber is generally 0.3-0.4 W / (m·k). Therefore, this invention uses nylon fiber, which has a higher heat transfer coefficient than rubber and good toughness, high strength, and strong compressive strength, to combine with phenolic resin. This makes the prepared composite material more closely resemble the heat transfer coefficient of rubber. The heat transfer coefficient of the nylon fiber-reinforced phenolic resin is 0.21-0.25 W / (m·k). The prepared mold has two-dimensional double-sided heat transfer characteristics, which can ensure that it closely resembles the actual vulcanization heat transfer process of the tire, greatly improving the accuracy of the mold in predicting the tire vulcanization time.

[0031] It is particularly important to emphasize that phenolic resin alone cannot be used as a mold to simulate the tire vulcanization process. Firstly, the heat transfer coefficient of phenolic resin is lower than that of rubber, almost only one-tenth of that of rubber, which would result in a mismatch with the actual vulcanization heat transfer process of a tire. Secondly, phenolic resin is quite brittle; if used as a mold, it would be crushed during vulcanization and become unusable. Similarly, while nylon fiber products have good toughness, high strength, and strong compressive strength, their heat transfer coefficient is higher than that of rubber, therefore they cannot be directly used to prepare molds to simulate the tire vulcanization process.

[0032] The present invention also provides a method for preparing the above-mentioned mold, comprising the following steps:

[0033] The product is obtained by impregnating nylon fiber products with a phenolic resin solution and then curing them.

[0034] According to this invention, nylon fiber products are first impregnated in a phenolic resin solution to ensure sufficient phenolic resin coating on the surface of the nylon fiber products. The phenolic resin solution is obtained by mixing phenolic resin with a solvent, preferably under stirring conditions. The solvent is preferably industrial alcohol, and the ratio of phenolic resin to solvent is preferably 1 kg:(2-3) L, such as 1 kg:2 L, 1 kg:2.2 L, 1 kg:2.4 L, 1 kg:2.5 L, 1 kg:2.6 L, 1 kg:2.8 L, or 1 kg:3 L, etc. Other ratios within this range are also applicable and will not be elaborated further. The nylon fiber products are preferably nylon fabric. This invention does not impose any particular restrictions on the specifications of the nylon fabric; any commercially available product is acceptable. In some embodiments of this invention, the preferred nylon fabric type is 1400 dtex / 2V1. In some embodiments of this invention, it is preferable to impregnate the nylon fiber products in the phenolic resin solution at room temperature for 15-40 minutes to ensure sufficient resin coating on the nylon fabric. It should be noted that if the required amount of adhesive is not achieved after a single application, i.e., the mass ratio of nylon fiber products to phenolic resin is not within the range of (3-4):1, the impregnation can be repeated until the required amount of adhesive is achieved.

[0035] According to the present invention, after the above-mentioned soaking and coating with adhesive is completed, it is preferable to dry the residual solvent on the surface of the nylon cord fabric and then perform a curing treatment to obtain the mold. In some embodiments of the present invention, it is preferable to wind the nylon cord fabric after drying the solvent using a tube winding machine. When the thickness of the resulting tube is relatively thin, heat dissipation is large, which is not conducive to internal heat transfer. Therefore, the present invention controls the thickness of the tube to be 10-20 mm, preferably 10-18 mm, more preferably 10-15 mm. Then the tube is placed in a vulcanization mold and cured. The curing temperature is generally 130-200°C, preferably 130-180°C, more preferably 130-150°C, and the time is 20 min-3 h, preferably 30 min-2 h, more preferably 30 min-1 h. The heat curing treatment is preferably carried out on a vulcanizing machine.

[0036] The method for preparing the mold provided by the present invention is simple and convenient. After soaking and coating the nylon fiber product with glue, it can be cured. No expensive instruments and equipment are required, the economic cost is low, and it is conducive to realizing industrial production.

[0037] The present invention also provides a method of using the above-mentioned mold, comprising the following steps:

[0038] The colloidal raw material is placed in the mold, and a thermocouple is embedded in the corresponding position before vulcanization. The temperature rise behavior of the colloidal raw material during vulcanization is monitored in real time.

[0039] In some embodiments of the present invention, the colloidal raw material is preferably a compounded rubber. The operation of embedding thermocouples at appropriate locations can be performed using techniques well-known to those skilled in the art, wherein the number and distribution of the thermocouples can be selected according to actual needs. In some embodiments of the present invention, the vulcanization temperature is 150–220°C, preferably 150–200°C, and more preferably 160–180°C. During the vulcanization process, it is preferable to heat the mold from both sides using an upper heating plate and a lower heating plate; the temperatures of the upper and lower heating plates can be the same or different.

[0040] Through testing, this invention found that the heat transfer coefficient of the provided mold is 0.23 W·m. -1 ·K -1 The mold, with its heat transfer coefficient closely matching that of the rubber, not only serves a fixing function but also acts as the rubber itself. Furthermore, the temperature rise curves at different measuring points within the same plane are identical, while the temperature rise curves at different measuring points within different planes differ, indicating that the mold provided by this invention possesses two-dimensional, double-sided heat transfer characteristics. Additionally, the temperature rise curves of the thermocouples embedded in the same plane within the actual tire or the mold closely match, indicating that the mold provided by this invention more closely reflects the heat transfer of the actual tire during the vulcanization process, which is beneficial for accurately predicting the tire's vulcanization time.

[0041] Therefore, the molds involved in the above technical solutions can be applied to predict tire vulcanization time and reduce industrialization costs, which has good practical significance.

[0042] To further illustrate the present invention, the following embodiments provide a detailed description. All experimental materials used in the following embodiments of the present invention can be purchased commercially or prepared according to conventional preparation methods well known to those skilled in the art. The thermosetting phenolic resin, specifically model RT7-TSPR, was purchased from Jinan Shengquan Group.

[0043] Example 1

[0044] (1) Dissolve 1 kg of thermosetting phenolic resin in 2.5 L of ethanol solution (ethanol content is 95%), stir until dissolved, and then pour into an impregnation tank. Immerse 1200 g of 1400 dtex / 2V1 nylon cord fabric in the phenolic resin impregnation tank for 20 min, then dry the solvent. The total weight should be controlled to 1500 g. If the weight of a single impregnation is insufficient, multiple impregnations can be performed after drying the solvent until the total weight meets the requirements. Finally, use a tube winding machine to wind the nylon cord fabric with phenolic resin into a tube with a thickness of 15 mm. Place the tube into the corresponding mold and heat-cur it at 150 °C for 30 min on a vulcanizing machine to obtain the composite material.

[0045] (2) Cut the composite material according to the tire section height to obtain a ring-shaped phenolic / nylon mold.

[0046] Example 2

[0047] (1) Dissolve 1 kg of thermosetting phenolic resin in 3 L of ethanol solution (ethanol content is 95%), stir until dissolved, and then pour into an impregnation tank. Immerse 1200 g of 1400 dtex / 2V1 nylon cord fabric in the phenolic resin impregnation tank for 20 min, then dry the solvent. The total weight should be controlled to 1600 g. If the weight of a single impregnation is insufficient, multiple impregnations can be performed after drying the solvent until the total weight meets the requirements. Finally, use a tube winding machine to wind the nylon cord fabric with phenolic resin into a tube with a thickness of 15 mm. Place the tube into the corresponding mold and heat-cur it at 160 °C for 25 min on a vulcanizing machine to obtain the composite material.

[0048] (2) Cut the composite material according to the tire section height to obtain a ring-shaped phenolic / nylon mold.

[0049] Example 3

[0050] (1) Dissolve 1 kg of thermosetting phenolic resin in 2 L of ethanol solution (ethanol content is 95%), stir until dissolved, and then pour into an impregnation tank. Immerse 1200 g of 1400 dtex / 2V1 nylon cord fabric in the phenolic resin impregnation tank for 30 min, then dry the solvent. The total weight should be controlled to 1550 g. If the weight of a single impregnation is insufficient, multiple impregnations can be performed after drying the solvent until the total weight meets the requirements. Finally, use a tube winding machine to wind the nylon cord fabric with phenolic resin into a tube with a thickness of 15 mm. Place the tube into the corresponding mold and heat-cur it at 180°C for 25 min on a vulcanizing machine to obtain the composite material.

[0051] (2) Cut the composite material according to the tire section height to obtain a ring-shaped phenolic / nylon mold.

[0052] Figure 1 The phenolic / nylon molds of different heights are shown to be circular in shape and cut into different heights according to actual needs.

[0053] Performance testing

[0054] The rubber compound was reproduced and arranged in the mold obtained in Example 1 according to the tire cross-section rubber compound distribution, and then... Figure 2 As shown in Figure A, embed the corresponding thermocouples. Finally, place the mold on the vulcanizing machine and perform pressure vulcanization with the upper and lower parts of the mold at a temperature of 158°C, recording the temperature rise of the internal thermocouples.

[0055] Test results are as follows Figure 2As shown in Figure B, it can be seen that the temperature rise curves of different temperature measuring points within the same plane are the same, while the temperature rise curves of different temperature measuring points within different planes are different, indicating that the mold provided by the present invention has two-dimensional double-sided heat transfer characteristics.

[0056] Because a break was found in the temperature rise curve when plotting temperature measurement point 1, therefore... Figure 2 A and Figure 2 B is not displayed.

[0057] Referring to the above method, according to Figure 3 As shown in Figure A, the corresponding thermocouples are embedded, and pressure vulcanization is carried out according to the upper temperature of the mold being 163℃ and the lower temperature being 151℃. The temperature rise of the internal thermocouples is recorded.

[0058] Test results are as follows Figure 3 As shown in Figure B, it can be seen that the temperature rise curves of different temperature measuring points within the same plane are the same, while the temperature rise curves of different temperature measuring points within different planes are different, indicating that the mold provided by the present invention has two-dimensional double-sided heat transfer characteristics.

[0059] This invention uses a simulated engineering tire (i.e., an actual tire) with a maximum cross-sectional thickness of 90mm, according to... Figure 4 As shown, thermocouples were embedded at five locations, and pressure vulcanization was performed with the inner mold temperature at 165°C and the outer mold temperature at 143°C. The temperature rise of the internal thermocouples was recorded. Simultaneously, the tire cross-section rubber compound was reproduced within the mold obtained in Example 1, and... Figure 4 As shown, thermocouples were embedded at five different locations. Finally, the mold was placed on a vulcanizing machine, and pressure vulcanization was performed with the upper part of the mold at 165℃ and the lower part at 143℃. The temperature rise of the internal thermocouples was recorded. The test results are as follows. Figure 5 As shown, the solid line represents the temperature change curve of the thermocouple inside the simulated engineering tire, and the dashed line represents the temperature change curve of the thermocouple inside the mold. It can be seen that the temperature rise curves of the thermocouples embedded in the same plane within the engineering tire or the mold are quite similar, indicating that the mold provided by this invention more closely matches the heat transfer of the actual tire during the vulcanization process, which is beneficial for accurately predicting the vulcanization time of the tire.

[0060] The thermal conductivity of the mold obtained in Example 1 was tested using a German Netzsch LFA 447 xenon lamp thermal conductivity instrument, according to the ASTM-E1461 laser flash method.

[0061] The test results are shown in Table 1:

[0062] Table 1

[0063]

[0064]

[0065] As can be seen from the data in Table 1, the thermal conductivity of the mold is 0.23 W·m. -1 ·K -1 The thermal conductivity of the vulcanized rubber, the compound rubber, and the mold is basically the same, indicating that the heat transfer coefficient of the mold is similar to that of the rubber. The mold can play the role of rubber while also fixing the rubber.

[0066] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The application of a mold in predicting tire vulcanization time, said mold being made of nylon fiber reinforced phenolic resin; The nylon fiber is nylon fabric; The mass ratio of the nylon fiber to the phenolic resin is (3~4):1; The thermal conductivity of the mold is 0.21~0.25 W / (m·k); The mold has two-dimensional double-sided heat transfer characteristics, which fits the actual vulcanization heat transfer process of the tire. The mold is a ring-shaped mold with a thickness of 10~20 mm.

2. The application according to claim 1, characterized in that, The phenolic resin is a thermosetting phenolic resin.

3. The application according to claim 1, characterized in that, The method for preparing the mold includes the following steps: It is obtained by impregnating nylon fibers with a phenolic resin solution and then curing them.

4. The application according to claim 3, characterized in that, The solvent in the phenolic resin solution is industrial alcohol; The ratio of phenolic resin to solvent in the phenolic resin solution is 1 kg:(2~3) L.

5. The application according to claim 3, characterized in that, The immersion time is 15-40 minutes.

6. The application according to claim 3, characterized in that, The curing temperature is 130~200℃ and the time is 20min~3h.

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