Tire high-temperature vulcanization repair adhesive

Abstract

The invention discloses a tire high-temperature vulcanization repair adhesive, and relates to the technical field of tires. The high-performance repair material suitable for the tires of the heavy engineering vehicles is developed by innovatively combining and using two functional aids, namely the 2-mercaptobenzothiazole cyclohexyl ammonium salt and the resinol, and the material shows excellent bonding strength, wear resistance and aging resistance under the working conditions of high temperature and high load.

Description

Technical Field

[0001] This invention relates to the field of tire technology, and more specifically to a high-temperature vulcanized repair adhesive for tires. Background Technology

[0002] Traditional tire repair adhesives are mainly divided into two categories: one type only repairs surface defects, with little regard for performance indicators, focusing solely on cosmetic restoration; the other type is a high-performance repair adhesive with a certain level of durability. Due to limitations in cost, storage, transportation, and usage, high-performance repair adhesives have formulations similar to tire formulations, but with significant simplifications. Therefore, their overall performance is generally poor, and the following problems are still likely to occur after tire repair:

[0003] (1) Interface adhesion failure: Traditional repair adhesives often use rosin resin, petroleum resin, etc. as tackifiers. These tackifiers cannot participate in the cross-linking reaction and will soften significantly at tire operating temperatures (>120℃), causing the bond strength between the repair layer and the tire body to decrease sharply with increasing temperature. Tests show that at 150℃, the peel strength of traditional repair adhesives will decrease by more than 40%.

[0004] (2) Defects in the vulcanization system: Conventional accelerators such as sulfenamides (CZ, NS, etc.) have uneven cross-linking networks (polysulfide bond ratio >60%) during high-temperature vulcanization, which directly leads to insufficient strength of the repaired part, making it prone to microcracks and wear under dynamic loads.

[0005] (3) Insufficient aging resistance: The interfacial strength retention rate of traditional repair adhesives is generally less than 60%.

[0006] Therefore, given the existing problems with tire repair adhesives, there is an urgent need to develop a new repair adhesive to solve these issues. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a high-temperature vulcanized repair adhesive for tires. By innovatively combining two functional additives, 2-thiol-based benzothiazole cyclohexane ammonium salt and resin acid amine phenol, a high-performance repair material suitable for heavy engineering vehicle tires is developed. This material exhibits excellent bonding strength, wear resistance and aging resistance under high temperature and high load conditions.

[0008] The technical solution of this invention is as follows:

[0009] The high-temperature vulcanized repair compound for tires includes a vulcanization system and functional additives. The vulcanization system includes 2-mercaptobenzothiazole cyclohexane ammonium salt, and the functional additives include resin acid amine resinol. Both 2-mercaptobenzothiazole cyclohexane ammonium salt and resin acid amine resinol are products manufactured by Lanxess, Germany.

[0010] Preferably, it also includes a rubber matrix and reinforcing fillers.

[0011] Preferably, the vulcanization system also includes sulfur, zinc oxide and stearic acid; the functional additives also include silane coupling agents and antioxidants.

[0012] Preferably, the weight percentages of each component are as follows: 100 parts rubber matrix, 50-65 parts reinforcing filler, 1.5-2 parts sulfur, 1-2 parts 2-mercaptobenzothiazole cyclohexammonium salt, 3-5 parts zinc oxide, 1-2 parts stearic acid, 3-6 parts resin acid amine phenol, 2-3 parts silane coupling agent, and 2-3 parts antioxidant.

[0013] Preferably, the rubber matrix comprises 60-80 parts of natural rubber (NR) and 20-40 parts of styrene-butadiene rubber (SBR).

[0014] Preferably, the reinforcing filler comprises 40-50 parts of carbon black and 10-15 parts of silica.

[0015] Preferably, the carbon black is carbon black N330.

[0016] Preferably, the silica is silica 175MP.

[0017] Preferably, the silane coupling agent is the silane coupling agent TESPT.

[0018] Preferably, the antioxidant is antioxidant 4020.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The high-temperature vulcanized tire repair adhesive of this invention is mainly designed to address common problems in the adhesion and vulcanization performance of general tire repair adhesives. It improves upon existing formulations by optimizing the crosslinking network structure, increasing tackiness, and enhancing the adhesive's performance. 2-Mitol-based benzothiazole cyclohexaneammonium salt is selected, whose cyclohexaneammonium salt structure can controllably release active thiol groups (-SH) at different temperatures, achieving a gradient distribution of crosslinking density (high density on the surface / moderate crosslinking in the inner layer). Resin acid amine resin is introduced, whose phenolic hydroxyl groups bond with rubber olefins to form a stronger adhesive network. The combination of 2-mercaptobenzothiazole cyclohexaneammonium salt and resin acid amine resin optimizes the crosslinking network structure, reduces the activation energy during vulcanization (lower vulcanization temperature, easier crosslinking reaction), and increases the vulcanization speed, thereby improving the overall performance of the repair adhesive. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0022] Examples 1-3 and Comparative Examples 1-3

[0023] The formulations of the high-temperature vulcanized repair adhesives for tires in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1:

[0024] Table 1. Formulations of tire high-temperature vulcanizing repair adhesives for Examples 1-3 and Comparative Examples 1-3

[0025]

[0026]

[0027] The preparation methods of the high-temperature vulcanized repair adhesives for tires in Examples 1-3 and Comparative Examples 1-3 include the following steps:

[0028] S1 First stage mixing: Mix NR, SBR1502, carbon black N330, antioxidant 4020, zinc oxide and stearic acid to 150℃ and discharge the glue.

[0029] S2 two-stage mixing: Add resin acid amine phenol or tackifying resin TYC0412, 175MP white carbon black, and TESPT, and mix until 145℃ for debinding.

[0030] S3 Final Mixing: Add sulfur, 2-mercaptobenzothiazole cyclohexane ammonium salt or accelerator CZ, and mix at 110℃ for 120 seconds to obtain the final rubber.

[0031] The tire rubber compounds prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to high-temperature vulcanization (high-temperature vulcanization conditions: 140℃ × 60min) and their performance was tested. The test results are shown in Table 2.

[0032] Table 2. Performance test results of rubber compounds after high-temperature vulcanization in Examples 1-3 and Comparative Examples 1-3.

[0033]

[0034]

[0035] As shown in Table 2, Example 1, which simultaneously added 2-thiol-benzothiazole cyclohexammonium salt and resin acid amine phenol, compared with Comparative Example 1, achieved a tensile strength of 23.5 MPa, an increase of approximately 22.4%, but the elongation at break decreased slightly; the tensile volume retention rate after aging was approximately 72%, an increase of approximately 22% compared with Comparative Example 1; the interfacial peel force was 5.9 N / mm, an increase of approximately 43.9%; the high-temperature interfacial peel force retention rate was approximately 74.6%, an increase of approximately 20.9% compared with Comparative Example 1; and the wear was reduced to 81 mm. 3 Performance was improved by approximately 19.8%. Vulcanization rate (T 90 The process is faster, but the scorching time is significantly shorter than that of control sample 1, so attention should be paid to storage and transportation conditions.

[0036] Comparative studies of Examples 1-3 revealed that using 2-thiol-benzothiazole cyclohexane ammonium salt alone increased the tensile strength of the vulcanizate by approximately 12%, but resulted in a 46% decrease in elongation at break; using resin acid amine resinol alone increased the interfacial peel strength by 26.8%, but excessive addition deteriorated the abrasion performance by 6.9%. From the perspective of material reaction mechanisms, 2-thiol-benzothiazole cyclohexane ammonium salt, as a novel vulcanization accelerator, can controllably release active thiol groups (-SH) at high temperatures, promoting the formation of a high-density single / disulfide crosslinking network. Resin acid amine resinol, as a multifunctional modifier, has phenolic hydroxyl groups in its molecular structure that can form hydrogen bonds with rubber molecules.

[0037] In addition, resin-acid amine resin has a certain activating effect on 2-thiol-benzothiazole cyclohexane ammonium salt. The phenolic hydroxyl group of resin-acid amine resin forms a hydrogen-bonded complex with the ammonium salt of 2-thiol-benzothiazole cyclohexane ammonium salt. This complex can significantly promote vulcanization at 135℃. This interaction reduces the vulcanization activation energy from 82.4 kJ / mol to 53 kJ / mol, achieving better vulcanization results at 135-140℃ and increasing the vulcanization rate, thus realizing low-temperature and high-efficiency vulcanization and improving repair efficiency.

[0038] The cross-linked network of the synergistic system exhibits a unique gradient structure depending on the difference in vulcanization temperature between the inner and outer layers: the surface layer has a higher cross-linking density, which increases wear resistance, while the inner layer has a slightly lower cross-linking density, which maintains toughness. The long-chain molecules of the resin acid amine resin can effectively fill the micropores of the 2-thiol benzothiazole cyclohexammonium salt cross-linked network, thereby reducing the Payne effect.

[0039] The high-temperature vulcanizing repair adhesive for tires of this invention exhibits significant advantages in practical applications: the vulcanization temperature can be reduced to 135℃, and the vulcanization efficiency is improved; in tests conducted on 16.00R25 wide-body tires in regions such as eastern Inner Mongolia and Xinjiang after tread repair, its performance is significantly better than the repair adhesive in Comparative Example 1. Follow-up tests were conducted 1.5 months after the repair was completed, as shown in Comparative Example 3:

[0040] Table 3. Practical application of the repair adhesive in Example 1 and Comparative Example 1.

[0041] Evaluation Project Comparative Example 1 Example 1 Performance differences Surface grinding performance Numerous wear grooves The surface is relatively smooth after wear. improve Average remaining pattern 44％ 51％ improve Repair edge cracks 21 articles 4 improve Repair layer peeling off 3 0 items improve

[0042] As shown in Table 3, field tests in mines have confirmed that the repair adhesive using the formula system of this invention has a significantly improved performance compared to traditional repair adhesive products, and can extend the service life of tires.

Claims

1. A high-temperature vulcanized tire repair adhesive, characterized in that, It includes a vulcanization system and functional additives, wherein the vulcanization system includes 2-thiol benzothiazole cyclohexammonium salt, and the functional additives include resin acid amine resinol.

2. The tire high-temperature vulcanization repair adhesive as described in claim 1, characterized in that, It also includes the rubber matrix and reinforcing fillers.

3. The high-temperature vulcanized repair adhesive for tires as described in claim 2, characterized in that, The vulcanization system also includes sulfur, zinc oxide, and stearic acid; functional additives also include silane coupling agents and antioxidants.

4. The high-temperature vulcanized repair adhesive for tires as described in claim 3, characterized in that, The weight percentages of each component are as follows: 100 parts rubber matrix, 50-65 parts reinforcing filler, 1.5-2 parts sulfur, 1-2 parts 2-mercaptobenzothiazole cyclohexammonium salt, 3-5 parts zinc oxide, 1-2 parts stearic acid, 3-6 parts resin acid amine phenol, 2-3 parts silane coupling agent, and 2-3 parts antioxidant.

5. The high-temperature vulcanized repair adhesive for tires as described in claim 4, characterized in that, The rubber matrix comprises 60-80 parts of natural rubber and 20-40 parts of styrene-butadiene rubber.

6. The high-temperature vulcanized repair adhesive for tires as described in claim 4, characterized in that, The reinforcing filler comprises 40-50 parts of carbon black and 10-15 parts of silica.

7. The high-temperature vulcanized repair adhesive for tires as described in claim 6, characterized in that, The carbon black is carbon black N330.

8. The high-temperature vulcanized repair adhesive for tires as described in claim 6, characterized in that, The silica is silica 175MP.

9. The high-temperature vulcanized repair adhesive for tires as described in claim 3, characterized in that, The silane coupling agent is TESPT.

10. The high-temperature vulcanized repair adhesive for tires as described in claim 3, characterized in that, The antioxidant is antioxidant 4020.

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