CN117777562B - Mining engineering tire carcass rubber and preparation method thereof - Google Patents

Abstract

The invention discloses a tire body rubber for a mining engineering tire and a preparation method thereof, and belongs to the technical field of tires. The technical proposal is as follows: the adhesive comprises the following components in parts by weight: 100 parts of natural rubber, 50-60 parts of carbon black, 8-10 parts of zinc oxide, 0.2-0.4 part of stearic acid, 1-2 parts of anti-aging agent 4020, 2-3 parts of tetrabutyl urea, 4-6 parts of bromomethyl p-tert-octylphenol formaldehyde resin, 0.6-1 part of cobalt salt, 0.1-0.2 part of peptizer, 4.5-8 parts of insoluble sulfur, 0.8-1.4 parts of accelerator and 0.15-0.3 part of scorch retarder. The invention solves the defects of insufficient durability and easy aging of the carcass rubber in the prior art.

Description

Mining engineering tire carcass rubber and preparation method thereof

Technical Field

The invention relates to the technical field of tires, and in particular to a carcass rubber for mining engineering tires and a preparation method thereof.

Background Art

Mining engineering tires have a large load capacity, so the deformation during use is much greater than that of passenger tires. They undergo continuous deformation during operation, which puts great pressure on the fatigue and aging resistance of tire rubber, especially in the carcass. Because it is inside the tire, heat accumulation is difficult to dissipate, causing the carcass to be in a high temperature state for a long time. At the same time, the cobalt salt adhesive used has poor aging resistance. Under long-term high-temperature fatigue conditions, the carcass rubber performance is seriously reduced, and the carcass rubber is often damaged, thus affecting the service life of the tire. Therefore, providing a mining engineering tire carcass rubber that can improve durability has become a research direction for solving the above problems of engineering tires.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, provide a mining engineering tire carcass rubber and a preparation method thereof, and solve the shortcomings of the prior art that the carcass rubber material has insufficient durability and is easy to age.

The technical solution of the present invention is:

On the one hand, the present invention provides a carcass rubber for a mining engineering tire, which comprises the following components, measured in parts by weight: 100 parts of natural rubber, 50-60 parts of carbon black, 8-10 parts of zinc oxide, 0.2-0.4 parts of stearic acid, 1-2 parts of p-phenylenediamine antioxidant 4020, 2-3 parts of tetrabutyl urea, 4-6 parts of bromomethyl p-tert-octylphenol formaldehyde resin, 0.6-1 parts of cobalt salt, 0.1-0.2 parts of peptizer, 4.5-8 parts of insoluble sulfur, 0.8-1.4 parts of accelerator, and 0.15-0.3 parts of scorch retarder.

Among them, bromomethyl 4-tert-octylphenol formaldehyde resin is a high-efficiency adhesive resin, and tetrabutyl urea is an antioxidant, which mainly plays a role in resisting thermal oxidative aging.

Preferably, the natural rubber is 20# standard rubber or Thai smoked rubber.

Preferably, the carbon black is N326 carbon black.

Preferably, the peptizer is a mixture of pentachlorothiophenol, an activator and a dispersant, namely, peptizer SJ-103.

Preferably, the cobalt salt is cobalt decanoate or cobalt stearate commonly used in rubber.

Preferably, the insoluble sulfur is OT10 or OT20.

Preferably, the accelerator is a sulfonamide accelerator DZ.

Preferably, the anti-scorch agent is a highly active anti-scorch agent CTP.

On the other hand, the present invention also provides a method for preparing the above-mentioned mining engineering tire carcass rubber, comprising the following steps:

S1 one-stage mixing

Add a plasticizer to natural rubber and put it into an internal mixer for plasticization, then put the obtained plasticized natural rubber and 40-45 parts of carbon black into the internal mixer for mixing for 40-50 seconds; then add an antioxidant 4020, zinc oxide and stearic acid into the internal mixer, mix at a speed of 36-42rpm, lift and press the lumps every 30-35 seconds, and discharge the rubber when the temperature of the rubber reaches 160-165°C; place it at room temperature for 4-6 hours to obtain a cooled masterbatch;

S2 two-stage mixing

The first stage masterbatch of step S1 and the remaining carbon black, tetrabutyl urea, bromomethyl-p-tert-octylphenol formaldehyde resin and cobalt salt are simultaneously put into an internal mixer, mixed at a speed of 35-38 rpm, and the lump is lifted and pressed every 30-35 seconds. When the temperature of the rubber material reaches 150-155° C., the rubber material is discharged and the sheets are dropped; the second stage masterbatch is placed at room temperature for 4-6 hours to obtain a cooled second stage masterbatch, and then the second stage masterbatch is returned according to the second stage mixing process, and the third stage masterbatch is placed at room temperature for 4-6 hours to obtain a third stage masterbatch;

S3 Final Refining

The three-stage masterbatch of step S2, insoluble sulfur, accelerator and anti-scorch agent are put into an internal mixer, mixed at a speed of 27-30 rpm, and lifted and pressed at intervals of 30-35s, 25-30s and 15-20s respectively. When the temperature of the rubber material reaches 95-100°C, the rubber material is discharged and sliced, and after being left to cool, the carcass rubber for mining engineering tire is obtained.

Compared with the prior art, the present invention has the following beneficial effects:

The tire body rubber prepared by the present invention has greatly improved heat-oxidative aging resistance and durability, etc., solves the problem of rubber delamination caused by the degradation of rubber aging performance that often occurs during the use of the tire body rubber, reduces the failure rate of tire body non-external force damage, and increases the service life of the tire.

DETAILED DESCRIPTION

In order to enable persons skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

Examples 1-3 and Comparative Examples 1-3

The formula of the carcass rubber of the mining engineering tire of Examples 1-3 and Comparative Examples 1-3 is shown in Table 1:

Table 1 Formula of the carcass rubber of mining engineering tires of Examples 1-3 and Comparative Examples 1-3

The preparation method of the carcass rubber of Examples 1-3 and Comparative Examples 1-3 comprises the following steps:

S1 one-stage mixing

The natural rubber is pre-added with a plasticizer and put into an internal mixer for plasticization, and then the plasticized natural rubber and 40 parts of carbon black are put into the internal mixer for mixing for 45 seconds; then, an antioxidant 4020, zinc oxide and stearic acid are added into the internal mixer, and mixing is performed at a speed of 38 rpm, and the lumps are lifted and pressed every 35 seconds. When the temperature of the rubber material reaches 162°C, the rubber material is discharged and sliced; and the masterbatch is placed at room temperature for 4 hours to obtain a cooled masterbatch;

S2 two-stage mixing

The first stage masterbatch of step S1 and the remaining carbon black, tetrabutyl urea, bromomethyl-p-tert-octylphenol formaldehyde resin and cobalt salt are simultaneously put into an internal mixer, mixed at a speed of 35 rpm, and the lump is lifted and pressed every 30 seconds. When the temperature of the rubber material reaches 153°C, the rubber material is discharged and the sheets are dropped; the second stage masterbatch is placed at room temperature for 4 hours to obtain a cooled second stage masterbatch, and then the second stage masterbatch is returned according to the second stage mixing process, and the third stage masterbatch is placed at room temperature for 4 hours to obtain a third stage masterbatch;

S3 Final Refining

The three-stage masterbatch of step S2, insoluble sulfur, accelerator and anti-scorch agent are put into an internal mixer and mixed at a speed of 27 rpm. The blocks are lifted and pressed at intervals of 30 s, 30 s and 20 s respectively. When the temperature of the rubber material reaches 98°C, the rubber material is discharged and sliced. After being left to cool, the carcass rubber for mining engineering tire is obtained.

The performance of the mining engineering tire carcass rubber prepared in Examples 1-3 and Comparative Examples 1-3 was tested, and the test results are shown in Table 2:

Table 2 Performance test results of mining engineering tire carcass rubber prepared in Examples 1-3 and Comparative Examples 1-3

Physical property test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Return to original Rev97/min 98 106 107 76 95 84 Tensile strength/MPa 27.2 27.3 27.7 26.4 26.2 27 Elongation at break/% 451 433 419 447 450 426 Shore hardness A/degree 70 70 71 69 68 71 Tear strength KN/m 95 97 103 86 82 95 Crack growth/mm 18 14 14 26 26 twenty one Aging retention rate/% 70 74 73 61 66 63 Adhesion strength/N 1692 1742 1738 1537 1553 1643 60℃tanδ 0.857 0.861 0.864 0.84 0.844 0.865

The crack growth was tested using a crack growth tester under the following test conditions: stroke 8 mm, frequency 5 Hz, and number of times 5W.

Comparing Example 2 with Comparative Example 1, it can be seen that under the same conditions of other components in the formula, when tetrabutyl urea and bromomethyl-p-tert-octylphenol formaldehyde resin are added to the carcass rubber, the vulcanization reversion time (Rev97) of the vulcanized rubber is extended by 39%, the tear strength is increased by about 13%, the crack growth resistance is increased by 46%, the aging retention rate is increased by 21%, and the bonding strength is increased by 13%. The aging resistance, crack resistance and bonding strength of the vulcanized rubber are significantly improved.

By comparing Example 2 with Comparative Example 2 and Comparative Example 3, it can be seen that by adding tetrabutyl urea and bromomethyl 4-tert-octylphenol formaldehyde resin to the carcass rubber at the same time, multiple key properties of the rubber are significantly better than those of the case where only one of the materials is added to the rubber. While the rubber to which only one of the materials is added improves some properties, it will lead to a decrease in other properties and cannot meet the performance requirements of the rubber.

From the performance of the two added materials, there are three main mechanisms for tetrabutyl urea to play an anti-aging role: First, free radical capture: it has a strong free radical capture ability, can capture and neutralize free radicals in the environment, and by capturing free radicals, block the free radical chain reaction, thereby reducing the damage of oxidation reactions to substances; second, metal ion chelation: it can form a complex with the metal ions in the cobalt salt, and by chelating the metal ions, it prevents the occurrence of catalytic oxidation reactions, thereby reducing the generation of free radicals and the oxidation reaction; third, the N-H bond in the molecular structure can provide active hydrogen atoms as a hydrogen source to participate in the antioxidant reaction. Bromomethyl tert-octylphenol formaldehyde resin is a vulcanized phenolic resin that can maintain a stable structure at high temperatures and is not easy to decompose. It also has high strength and metal bonding properties, and the reaction activity increases with the increase of bromine atom content.

In addition, the two have a strong synergistic effect. Tetrabutyl urea, as a nucleophilic reagent, attacks the bromine atom in the bromomethyl-p-tert-octylphenol formaldehyde resin through its lone pair of electrons on nitrogen, undergoing a nucleophilic substitution reaction to generate a tetrabutyl urea insert with a special structure. In the bromomethyl-p-tert-octylphenol formaldehyde resin, the tetrabutyl urea insert can be used as a crosslinker and curing agent to enhance the physical and mechanical properties of the resin while significantly improving its thermal stability and anti-aging properties, and forming a complex with the copper-plated steel wire to improve the bonding strength. Therefore, the simultaneous addition of the two can significantly improve the aging resistance, tear resistance and bonding strength of the tire rubber, thereby solving the problem of tire damage and delamination caused by the degradation of rubber performance during tire use, and can effectively increase the service life of the tire.

Claims (2)

1. The carcass rubber of mining engineering tire is characterized by comprising the following components by weight: 100 parts of natural rubber, 50-60 parts of carbon black, 8-10 parts of zinc oxide, 0.2-0.4 parts of stearic acid, antioxidant 4020 1-2 parts, tetrabutyl urea 2-3 parts, bromomethyl 4-tert-octylphenol formaldehyde resin 4-6 parts, cobalt salt 0.6-1 parts, peptizer 0.1-0.2 parts, insoluble sulfur 4.5-8 parts, accelerator 0.8-1.4 parts, anti-scorch agent 0.15-0.3 parts; the natural rubber is 20# standard rubber or Thai smoked sheet rubber; the carbon black is N326 carbon black; the peptizer is peptizer SJ-103; the cobalt salt is cobalt decanoate or cobalt stearate; the insoluble sulfur is OT10 or OT20; the accelerator is sulfonamide accelerator DZ; the anti-scorch agent is high-activity anti-scorch agent CTP. 2. The method for preparing the carcass rubber of mining engineering tire according to claim 1, characterized in that it comprises the following steps: S1 one-stage mixing Add a plasticizer to natural rubber and put it into an internal mixer for plasticization, then put the obtained plasticized natural rubber and 40-45 parts of carbon black into the internal mixer for mixing for 40-50 seconds; then add an antioxidant 4020, zinc oxide and stearic acid into the internal mixer, mix at a speed of 36-42rpm, lift and press the lumps every 30-35 seconds, and discharge the rubber when the temperature of the rubber reaches 160-165°C; place it at room temperature for 4-6 hours to obtain a cooled masterbatch; S2 two-stage mixing The first stage masterbatch of step S1 and the remaining carbon black, tetrabutyl urea, bromomethyl-p-tert-octylphenol formaldehyde resin and cobalt salt are simultaneously put into an internal mixer, mixed at a speed of 35-38 rpm, and the lump is lifted and pressed every 30-35 seconds. When the temperature of the rubber material reaches 150-155° C., the rubber material is discharged and the sheets are dropped; the second stage masterbatch is placed at room temperature for 4-6 hours to obtain a cooled second stage masterbatch, and then the second stage masterbatch is returned according to the second stage mixing process, and the third stage masterbatch is placed at room temperature for 4-6 hours to obtain a third stage masterbatch; S3 Final Refining The three-stage masterbatch of step S2, insoluble sulfur, accelerator and anti-scorch agent are put into an internal mixer, mixed at a speed of 27-30 rpm, and lifted and pressed at intervals of 30-35s, 25-30s and 15-20s respectively. When the temperature of the rubber material reaches 95-100°C, the rubber material is discharged and sliced, and after being left to cool, the carcass rubber for mining engineering tire is obtained.