Environment-friendly and efficient bonding method for inner tube body and inflating valve rubber mat and inner tube product

Abstract

The invention discloses an environment-friendly and efficient bonding method for an inner tube body and an inflating valve rubber mat and an inner tube product, and belongs to the field of tire rubber. The bonding method comprises the following steps that S1, electron beam irradiation is adopted to treat the inflating valve rubber mat, the irradiation parameters are that the voltage is 300-500 kV, and the dosage intensity is 50-110 kGy; s2, the inflating valve rubber mat subjected to irradiation treatment in the step S1 is attached to a designated position of an inner tube body; wherein the inflating valve rubber mat is made of a butyl rubber material with the prevulcanization degree of 0%-50%. The bonding process is environment-friendly, and the production efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of tire rubber, specifically relating to an environmentally friendly and efficient method for bonding the inner tube carcass to the valve stem gasket and an inner tube product. Background Technology

[0002] While semi-steel passenger car tires have largely adopted tubeless designs, all-steel heavy-duty truck tires, due to their high structural strength, heavy load capacity, and complex operating environments, still require tubed construction in some cases. Inner tubes ensure airtightness while simplifying the repair process for long-haul truck tires, reducing maintenance costs and improving efficiency by replacing the inner tube separately.

[0003] Traditional all-steel tire inner tubes consist of an inner tube carcass and a valve stem gasket. The bonding quality between these components directly affects the airtightness and durability of the inner tube, especially the bonding strength between the inner tube carcass and the valve stem gasket. Currently, the industry commonly uses adhesive paste as a binder, whose main component is a mixture of butyl rubber (CIIR / BIIR) and 120# gasoline, as described in patent CN117004346A. However, this technology has the following significant drawbacks: Environmental issues: gasoline in the adhesive paste is a volatile organic compound (VOC), and its production, storage, and use require strict control, and the volatilization process will pollute the environment. Process limitations: the adhesive paste can only achieve effective bonding after the gasoline has completely volatilized, which not only prolongs the production cycle but also increases energy consumption. Policy risks: according to the Ministry of Ecology and Environment's "Technical Guidelines for Formulating Emergency Emission Reduction Measures for Key Industries in Heavy Pollution Weather (2020 Revised Edition)," tire companies with adhesive paste production processes will be classified as Grade D, seriously affecting the sustainable development of enterprises.

[0004] With increasingly stringent environmental regulations, the application of traditional adhesive bonding technology faces significant challenges, making the development of an efficient and environmentally friendly bonding technology between the inner tube carcass and the valve stem gasket an urgent industry need. However, no publicly reported environmentally friendly alternatives have been found to date. Summary of the Invention

[0005] One objective of this invention is to provide an environmentally friendly and efficient method for bonding the inner tube carcass to the valve stem gasket, applicable to the bonding between the inner tube carcass and the valve stem gasket of an all-steel heavy-duty truck tire. This invention is achieved through the following technical solution: An environmentally friendly and efficient method for bonding the inner tube carcass to the valve stem gasket includes the following steps: S1. Electron beam irradiation is used to treat the valve gasket, with irradiation parameters of voltage 300-500kV and dose intensity 50-110kGy. S2. Apply the valve seat gasket after S1 irradiation treatment to the designated position on the inner tube body. The valve stem gasket is made of butyl rubber with a pre-vulcanization degree of 0%-50%. The electron beam irradiation treatment is carried out using an EPS irradiation device.

[0006] Another object of the present invention is to provide a method for preparing butyl rubber inner tube, comprising the following steps: bonding the valve stem gasket to the inner tube body according to the aforementioned method; S4. Spray talcum powder evenly on the surface of the inner tube carcass, then align the two ends of the carcass and press the joint together to obtain a ring-shaped inner tube carcass. S5: The ring-shaped inner tube preform of S4 is vulcanized at 160-190℃ for 5-30 minutes to obtain a rubber inner tube.

[0007] The present invention also provides a butyl rubber inner tube, which is prepared by the aforementioned preparation method.

[0008] The bonding method of the present invention can be used independently or as part of the complete tire manufacturing process. The rubber compound formulation described in S1 is applicable to the entire inner tube manufacturing process, including tire body forming, valve bonding, and final vulcanization.

[0009] Compared with existing technologies, this invention significantly improves the adhesion performance between the valve stem gasket and the inner tube carcass by optimizing the pre-vulcanization degree and irradiation treatment process of the valve stem gasket, as specifically demonstrated below: 1. Environmentally friendly process, improving production efficiency. Compared with the traditional high pre-cured rubber pads that rely on gasoline-based hazardous chemicals or non-environmentally friendly solvent-based adhesives, the irradiation modification process of this invention does not require the addition of organic solvents, meeting the requirements of green manufacturing; on the other hand, it improves production efficiency by eliminating the processes of adhesive preparation, spraying and drying.

[0010] 2. By limiting the irradiation voltage to 300-500kV and the irradiation dose intensity to 50-110kGy, controllable degradation occurs on the surface of the rubber pad. This causes some molecular chains to break and generate active free radicals, significantly improving surface adhesion while avoiding mechanical property degradation due to excessive degradation. If the irradiation voltage is below 300kV or the dose intensity is below 50kGy, the surface degradation of the rubber pad is insufficient, resulting in fewer active sites and unsatisfactory adhesive performance. If the irradiation voltage is above 500kV or the dose intensity is above 110kGy, excessive degradation occurs, severely damaging the surface structure of the rubber pad and affecting the interfacial strength during subsequent vulcanization. This invention, by limiting the above irradiation parameter range, ensures a moderate degree of surface degradation for the rubber pad, improving adhesion while maintaining the mechanical integrity of the pad.

[0011] 3. Improved adhesion. This invention uses a butyl rubber system with a pre-vulcanization degree of 0%-50%, which allows the rubber pad to maintain a certain mechanical strength while still possessing sufficient unvulcanized active groups, thereby forming a stronger chemical crosslink with the tire carcass during the subsequent vulcanization process. Detailed Implementation

[0012] To facilitate understanding of the present invention, a more complete description is provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0013] The present invention will be described in detail below with reference to specific embodiments.

[0014] Example 1 The tubular inner tube used in this embodiment is a butyl rubber inner tube for automobiles. Its rubber compound properties refer to the physical and mechanical property requirements for automobile inner tubes in GB / T7036.1-2023. Its main characteristics include: butyl inner tube: tensile strength ≥8.4Mpa, elongation at break ≥450%, and thermal tensile deformation ≤35%.

[0015] The valve stem gasket, pre-cured to 20% butyl rubber, is irradiated using an EPS irradiation device at a voltage of 350 kV and an intensity of 80 kg. Then, using an automated positioning fixture, the irradiated gasket is attached to a designated position on the inner tube carcass. Talc powder is evenly sprayed onto the surface of the inner tube carcass, and both ends of the carcass are then placed flat into the clamps of a splicing machine. The splice ends are cut to expose a fresh, clean bonding surface. The clamps align and press the two ends of the inner tube carcass together to obtain the inner tube blank. The inner tube blank is then placed in a vulcanization mold and vulcanized at 180°C for 10 minutes to obtain the finished inner tube.

[0016] After the irradiated valve stem gasket is bonded to the inner tube body, the adhesion between the valve stem gasket and the inner tube body is subjectively judged by manually pulling on it. The adhesion between the valve stem gasket and the inner tube body of the vulcanized inner tube is tested according to the national standard GB / T 7036.1-2023.

[0017] Example 2 The inner tube of Example 2, as well as the adhesion test between the rubber pad and the inner tube body, were the same as those in Example 1.

[0018] The butyl rubber system valve gasket with a pre-vulcanization degree of 30% is irradiated using an EPS irradiation device under irradiation voltage of 450KV and irradiation intensity of 100KGy to give the gasket surface a certain degree of adhesion. Then, it is precisely positioned and bonded to the inner tube carcass using automated tooling. Talc powder is evenly sprayed onto the surface of the inner tube carcass, and then both ends of the inner tube carcass are placed flat into the clamps of the splicing machine. The splice end faces are cut to expose fresh and clean bonding surfaces. The clamps align the two ends and press the splice together to obtain the inner tube blank.

[0019] The inner tube blank is placed in a vulcanizing mold and vulcanized at 185°C for 6 minutes to obtain the finished inner tube.

[0020] Example 3 The inner tube of Example 3, as well as the adhesion test between the rubber pad and the inner tube body, were the same as those in Example 1.

[0021] The butyl rubber system valve gasket with a pre-vulcanization degree of 40% is irradiated using an EPS irradiation device under irradiation voltage of 500KV and irradiation intensity of 100KGy to give the gasket surface a certain degree of adhesion. Then, it is precisely positioned and bonded to the inner tube carcass using automated tooling. Talc powder is evenly sprayed onto the surface of the inner tube carcass, and then both ends of the inner tube carcass are placed flat into the clamps of the splicing machine. The splice end faces are cut to expose fresh and clean bonding surfaces. The clamps align the two ends and press the splice together to obtain the inner tube blank.

[0022] The inner tube blank is placed in a vulcanizing mold and vulcanized at 185°C for 8 minutes to obtain the finished inner tube.

[0023] Comparative Example 1 The tests on the inner tube carcass and the adhesion between the rubber pad and the inner tube carcass in Comparative Example 1 were the same as those in Example 1.

[0024] The butyl rubber valve seat with a pre-vulcanization degree of 70% is irradiated using an EPS irradiation device under irradiation voltage of 400KV and irradiation intensity of 80KGy to give the surface of the gasket a certain degree of adhesion. Then, it is precisely positioned and bonded to the inner tube carcass using automated tooling. Talc powder is evenly sprayed onto the surface of the inner tube carcass, and then both ends of the inner tube carcass are placed flat into the clamps of the splicing machine. The splice end faces are cut to expose fresh and clean bonding surfaces. The clamps align the two ends and press the splice together to obtain the inner tube blank.

[0025] The inner tube blank is placed in a vulcanizing mold and vulcanized at 180°C for 7 minutes to obtain the finished inner tube.

[0026] Comparative Example 2 The tests on the inner tube carcass and the adhesion between the rubber pad and the inner tube carcass in Comparative Example 2 were the same as those in Example 1.

[0027] The butyl rubber valve seat with a pre-vulcanization degree of 90% is irradiated using an EPS irradiation device under irradiation voltage of 500KV and irradiation intensity of 100KGy to give the surface of the gasket a certain degree of adhesion. Then, it is precisely positioned and bonded to the inner tube carcass using automated tooling. Talc powder is evenly sprayed onto the surface of the inner tube carcass, and then both ends of the inner tube carcass are placed flat into the clamps of the splicing machine. The splice end faces are cut to expose fresh and clean bonding surfaces. The clamps align the two ends and press the splice together to obtain the inner tube blank.

[0028] The inner tube blank is placed in a vulcanizing mold and vulcanized at 180°C for 7 minutes to obtain the finished inner tube.

[0029] Comparative Example 3 The tests on the inner tube carcass and the adhesion between the rubber pad and the inner tube carcass in Comparative Example 3 were the same as those in Example 1.

[0030] The butyl rubber system valve gasket with a pre-vulcanization degree of 30% is irradiated using an EPS irradiation device under irradiation voltage of 300KV and irradiation intensity of 40KGy to give the gasket surface a certain degree of adhesion. Then, it is precisely positioned and bonded to the inner tube carcass using automated tooling. Talc powder is evenly sprayed onto the surface of the inner tube carcass, and then both ends of the inner tube carcass are placed flat into the clamps of the splicing machine. The splice end faces are cut to expose fresh and clean bonding surfaces. The clamps align the two ends and press the splice together to obtain the inner tube blank.

[0031] The inner tube blank is placed in a vulcanizing mold and vulcanized at 185°C for 10 minutes to obtain the finished inner tube.

[0032] Comparative Example 4 The tests on the inner tube carcass and the adhesion between the rubber pad and the inner tube carcass in Comparative Example 4 were the same as those in Example 1.

[0033] The butyl rubber system valve gasket with a pre-vulcanization degree of 30% is irradiated using an EPS irradiation device under irradiation voltage of 500KV and irradiation intensity of 120KGy to give the gasket surface a certain degree of adhesion. Then, it is precisely positioned and bonded to the inner tube carcass using automated tooling. Talc powder is evenly sprayed onto the surface of the inner tube carcass, and then both ends of the inner tube carcass are placed flat into the clamps of the splicing machine. The splice end faces are cut to expose fresh and clean bonding surfaces. The clamps align the two ends and press the splice together to obtain the inner tube blank.

[0034] The inner tube blank is placed in a vulcanizing mold and vulcanized at 185°C for 10 minutes to obtain the finished inner tube.

[0035] The experimental results obtained from the above embodiments and comparative examples of the present invention are shown in Table 1.

[0036] Table 1

[0037] Note: ● - Strong adhesion, no separation after manual tearing; ○ - Weak adhesion, easily separated after manual tearing.

[0038] Traditional valve stem gaskets have a pre-vulcanization degree of approximately 80%, resulting in high material hardness. The gasket used in this invention employs butyl rubber as its rubber system, with a pre-vulcanization degree of 0%-50%. After irradiation treatment, the gasket surface degrades, and some molecular chains break, increasing the surface viscosity and facilitating adhesion. If the pre-vulcanization degree is too high, the gasket may not achieve the desired adhesion after irradiation. Furthermore, this invention limits the pre-treatment irradiation voltage to 300-500 kV and the irradiation dose intensity to 50-110 kGy. Both excessively high and low irradiation voltages and dose intensities can lead to poor adhesion. Too low a voltage and dose intensity result in insufficient degradation and inadequate adhesion; too high a voltage and dose intensity lead to excessive degradation, which is detrimental to subsequent vulcanization.

[0039] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for bonding an environmentally friendly and efficient inner tube carcass to a valve stem gasket, characterized in that, Includes the following steps: S1. Electron beam irradiation is used to treat the valve gasket, with irradiation parameters of voltage 300-500kV and dose intensity 50-110kGy. S2. Apply the valve seat gasket after S1 irradiation treatment to the designated position on the inner tube body. The valve stem gasket is made of butyl rubber material with a pre-vulcanization degree of 0%-50%.

2. The method for bonding the inner tube body to the valve stem gasket according to claim 1, characterized in that, The electron beam irradiation treatment is carried out using an EPS irradiation device.

3. A method for preparing a butyl rubber inner tube, characterized in that, Includes the following steps: The valve stem gasket and the inner tube body are bonded according to the method described in claim 1; S3. Spray talcum powder evenly on the surface of the inner tube carcass, then align the two ends of the inner tube carcass and press the joint together to obtain a ring-shaped inner tube carcass. S4. The annular inner tube preform from S3 is vulcanized at 160-190℃ for 5-30 minutes to obtain a rubber inner tube.

4. A butyl rubber inner tube, characterized in that, It is prepared by the preparation method described in claim 3.

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