Wear-resistant rubber for seam allowance of truck radial tire and preparation method of wear-resistant rubber

Abstract

The invention discloses a seam allowance wear-resistant rubber for a truck radial tire, and belongs to the field of tires. In order to solve the problem of low air tightness of the bead wear-resistant rubber in the prior art, the bead wear-resistant rubber is prepared from the following components: a raw rubber composition, a carbon black composition, stearic acid, zinc oxide, an anti-aging agent composition, protective wax, softening oil, a resin mixture, light magnesium oxide, insoluble sulfur, an accelerant mixture, a scorch retarder CTP and a hardening reinforcing agent. The process is simple and convenient to operate, the components and the process are optimized, so that the air tightness of the seam allowance rubber material is higher, the rubber material, the filler and the chemical material are dispersed more uniformly, the air tightness of the rubber material is improved, and the aging resistance is improved.

Description

Technical Field

[0001] The invention relates to a wear-resistant rubber for a radial load-carrying tire and a preparation method thereof, and in particular to a formula and a preparation method of a wear-resistant rubber for a radial load-carrying tire with high air retention for a tubeless all-steel radial load-carrying tire, belonging to the field of tires. Background Art

[0002] Tubeless all-steel load-bearing radial tire is a type of radial tire. Its internal skeleton material is all steel cord, hence the name all-steel load-bearing radial tire. It is mostly used in freight trucks and buses. Since tubeless tires have no inner tube, they have higher requirements on tire air retention than tube-type tires.

[0003] During the use of tubeless all-steel load-bearing radial tires, the bead area needs to bear the vehicle load, transmit the braking force and steering force, and bear huge stress. The heat generated by the brake drum will also be transmitted to the wear-resistant rubber position of the wheel mouth through the rim, so that the wear-resistant rubber of the wheel mouth in contact with the rim is affected by high temperature aging, and the performance gradually decreases, affecting subsequent loading and unloading and refurbishment;

[0004] At present, when designing the wear-resistant rubber formula of tubeless all-steel load-bearing radial tires, domestic and foreign tire companies all use natural rubber + butadiene rubber as the main raw rubber design. However, due to the poor air tightness and aging resistance of natural rubber and butadiene rubber, the design of wear-resistant rubber at the tip has good processability, but this design will lead to poor air retention and aging resistance of the wear-resistant rubber at the tip. Some tubeless tires have the problem of falling off at the tip when dismantling after use;

[0005] The gas in the tubeless all-steel radial load-carrying tire is in direct contact with the wear-resistant rubber at the tip. Since the wear-resistant rubber at the tip has poor air tightness, air will slowly migrate through the rubber, causing the tire's internal pressure to drop. The reduction in internal pressure will increase the tire's rolling resistance and fuel consumption. The reduction in internal pressure will cause the tire to deform more, generate more heat, and reduce tire safety.

[0006] How to solve the above-mentioned technical problems of aging resistance and air retention of the wear-resistant rubber at the sub-mouth is a technical problem that needs to be solved in the current field of rubber tire processing technology. Summary of the invention

[0007] Aiming at the problem of "low air tightness of the wear-resistant rubber at the tip" in the prior art, a wear-resistant rubber at the tip of a load-carrying radial tire and a preparation method thereof are proposed.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is that a wear-resistant rubber for the tip of a load-carrying radial tire is composed of the following components in parts by weight:

[0009] 80-120 parts of raw rubber composition, 65-75 parts of carbon black, 1.5-2.5 parts of stearic acid, 2.5-4.5 parts of zinc oxide, 3-5 parts of antioxidant composition, 1-2 parts of protective wax, 4-8 parts of softening oil, 6-10 parts of resin mixture, 1-1.5 parts of light magnesium oxide, 1-1.5 parts of insoluble sulfur, 1.8-2.7 parts of accelerator mixture, 0.25-0.45 parts of anti-scorch agent CTP, and 1.5-2.5 parts of hardening and reinforcing agent.

[0010] Optimally, the wear-resistant rubber of the radial truck tire is composed of the following components in parts by weight:

[0011] 90-110 parts of raw rubber composition, 65-70 parts of carbon black, 1.5-2 parts of stearic acid, 3-4 parts of zinc oxide, 3.5-4.5 parts of antioxidant composition, 1-1.5 parts of protective wax, 4-7 parts of softening oil, 8-10 parts of resin mixture, 1-1.5 parts of light magnesium oxide, 1-1.5 parts of insoluble sulfur, 1.8-2.5 parts of accelerator mixture, 0.3-0.4 parts of anti-scorch agent CTP, and 2-2.5 parts of hardening and reinforcing agent.

[0012] Optimally, the wear-resistant rubber of the radial truck tire is composed of the following components in parts by weight:

[0013] 100 parts of raw rubber composition, 68 parts of carbon black, 2 parts of stearic acid, 3.5 parts of zinc oxide, 3.5 parts of antioxidant composition, 1 part of protective wax, 5 parts of softening oil, 8 parts of resin mixture, 1 part of light magnesium oxide, 1.25 parts of insoluble sulfur, 2.2 parts of accelerator mixture, 0.3 parts of anti-scorch agent CTP, and 2 parts of hardening and reinforcing agent.

[0014] Optimally, the wear-resistant rubber of the radial truck tire is composed of the following components in parts by weight:

[0015] 100 parts of raw rubber composition, 70 parts of carbon black, 2 parts of stearic acid, 3.5 parts of zinc oxide, 3.5 parts of antioxidant composition, 1 part of protective wax, 5 parts of softening oil, 9 parts of resin mixture, 1 part of light magnesium oxide, 1.25 parts of insoluble sulfur, 2.2 parts of accelerator mixture, 0.3 parts of anti-scorch agent CTP, and 2 parts of hardening and reinforcing agent.

[0016] Optimized, the wear-resistant rubber of the radial tire, the raw rubber in the raw rubber composition is a raw rubber system that does not contain natural rubber, and the raw rubber composition includes styrene-butadiene rubber and halogenated butyl rubber;

[0017] The styrene butadiene rubber includes one or a mixture of two of emulsion polymerized styrene butadiene rubber SBR1502 and SBR1500; the halogenated butyl rubber includes chlorinated butyl rubber, and the chlorinated butyl rubber includes a mixture of one or more of high Mooney viscosity, medium Mooney viscosity, and low Mooney viscosity chlorinated butyl rubber.

[0018] Optimally, the carbon black of the abrasion-resistant rubber of the above-mentioned radial truck tire is one of N234 or N220 carbon black or a mixture of the two;

[0019] The hardening and reinforcing agent includes hardening and reinforcing agent 8180, and the hardening and reinforcing agent 8180 is a bismaleimide derivative;

[0020] Optimized, the above-mentioned radial tire wear-resistant rubber, the accelerator includes accelerator NS and accelerator CZ;

[0021] The antioxidant composition includes antioxidant RD and antioxidant 4020;

[0022] The resin mixture includes a tackifying resin and a hydrocarbon resin mixture; the tackifying resin includes one or a mixture of two of octylphenol formaldehyde tackifying resin and tert-butylphenol formaldehyde tackifying resin.

[0023] Optimally, in the above-mentioned radial tire wear-resistant rubber, the zinc oxide is a mixture of one or more of indirect zinc oxide, active zinc oxide, and nano zinc oxide;

[0024] The softening oil includes a mixture of one or more of naphthenic oil, heavy naphthenic oil and environmentally friendly aromatic oil.

[0025] A method for preparing the above-mentioned radial tire wear-resistant rubber, comprising the following steps:

[0026] 1) Weigh the ingredients of the wear-resistant rubber formula for radial truck tires according to the proportion of ingredients;

[0027] 2) preparing a rubber mix; adding halogenated butyl rubber, tackifying resin, hydrocarbon resin mixture, light magnesium oxide, and part of carbon black into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain a masterbatch; the weight of the carbon black added in this step is 60% of the weight of the halogenated butyl rubber;

[0028] 3) preparing a second-stage masterbatch; adding the first-stage masterbatch, styrene-butadiene rubber, antioxidant RD, antioxidant 4020, protective wax and the remaining carbon black into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain a second-stage masterbatch;

[0029] 4) preparing a three-stage masterbatch; adding the second-stage masterbatch into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain a three-stage masterbatch;

[0030] 5) preparing the final rubber mix; adding the three-stage masterbatch, zinc oxide, insoluble sulfur OT20, accelerator NS, accelerator CZ, hardening and reinforcing agent, and anti-scorching agent CTP into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain the final rubber mix.

[0031] The optimized method for preparing the wear-resistant rubber of the radial tire is as follows:

[0032] In step 2), the speed of the internal mixer is adjusted to 45 rpm, the upper push bolt pressure is 0.45-0.55 MPa, and the push bolt is pressed and mixed for 30 seconds;

[0033] Raise the top bolt, add softened oil into the internal mixer, press the top bolt, and mix for 20 seconds;

[0034] Lift the top bolt for cleaning, press the top bolt for mixing for 20 seconds, open the discharge door to discharge glue, control the discharge temperature at 140-150℃, and extrude the next sheet through the extruder;

[0035] In step 3), the speed of the internal mixer was adjusted to 45 rpm, the upper push bolt pressure was 0.45-0.55 MPa, and the push bolt was pressed and mixed for 25 seconds;

[0036] Lift the top bolt for cleaning, adjust the speed of the internal mixer to 40rpm, press the top bolt and mix for 30 seconds, open the discharge door to discharge the glue, control the discharge temperature at 145-150℃, and extrude the next sheet with the extruder;

[0037] In step 4), the speed of the internal mixer was adjusted to 40 rpm, the upper push bolt pressure was 0.45-0.55 MPa, and the push bolt was pressed and mixed for 25 seconds;

[0038] Lift the top bolt for cleaning for 5 seconds, press the top bolt for mixing for 30 seconds, open the discharge door to discharge glue, control the discharge temperature at 140-150℃, and extrude the next sheet through the extruder;

[0039] In step 5), the speed of the internal mixer was adjusted to 26 rpm, and the top bolt was pressed and mixed for 25 seconds;

[0040] Raise the top plug for cleaning for 5 seconds, press the top plug for mixing for 25 seconds;

[0041] Raise the top bolt, press the top bolt and mix for 25 seconds, raise the top bolt, open the discharge door to discharge the glue, control the discharge temperature at 95-105℃, open the mixing mill to unload the sheets, cool and build stacks.

[0042] The beneficial effects of this application are:

[0043] By eliminating the use of natural rubber and butadiene rubber with poor air tightness and poor aging resistance in the raw rubber system, and using styrene-butadiene rubber and halogenated butyl rubber with good air tightness and aging resistance, the air tightness and aging resistance of the main body of the formula are improved. By using three antioxidants, RD, 4020, and protective wax, the comprehensive protective performance of the formula protection system, such as resistance to ozone, thermal oxygen, and fatigue, is improved. By using zinc oxide and low sulfur and high accelerator dosage, an effective vulcanization system is formed to improve the aging resistance of the vulcanization system. By using modulus enhancers and high specific surface area carbon black, the tensile properties, hardness and modulus of the fully synthetic rubber mouth wear-resistant rubber are improved, and the stress deformation of the tire bead is reduced. This application optimizes the process so that fillers and chemical materials are more evenly distributed in different raw rubbers, thereby improving the aging resistance and air tightness of the rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A cross-sectional view of a tire where the tubeless tire mouth wear-resistant rubber of the present application is located;

[0045] In the figure, point A is the wear-resistant rubber of the sub-mouth. DETAILED DESCRIPTION

[0046] The present application provides a wear-resistant rubber for a radial truck tire, which is composed of the following components:

[0047] Raw rubber composition, carbon black, stearic acid, zinc oxide, antioxidant composition, protective wax, softening oil, resin mixture, light magnesium oxide, insoluble sulfur, accelerator mixture, scorch retarder CTP, and hardening and reinforcing agent.

[0048] The raw rubber in the raw rubber composition is a raw rubber system without natural rubber, and the raw rubber composition includes styrene-butadiene rubber and halogenated butyl rubber. The styrene-butadiene rubber includes one or a mixture of two of emulsion polymerized styrene-butadiene rubber SBR1502 and SBR1500; the halogenated butyl rubber includes chlorinated butyl rubber, and the chlorinated butyl rubber includes one or a mixture of high Mooney viscosity, medium Mooney viscosity, and low Mooney viscosity chlorinated butyl rubber.

[0049] The carbon black is one of N234 or N220 carbon black or a mixture of both.

[0050] The hardening and reinforcing agent includes hardening and reinforcing agent 8180, and hardening and reinforcing agent 8180 is a bismaleimide derivative.

[0051] The accelerators include accelerator NS and accelerator CZ, and the antioxidant composition includes antioxidant RD and antioxidant 4020.

[0052] The resin mixture includes a tackifying resin and a hydrocarbon resin mixture, and the tackifying resin includes one or a mixture of two of octylphenol formaldehyde tackifying resin and tert-butylphenol formaldehyde tackifying resin.

[0053] The zinc oxide is a mixture of one or more of indirect zinc oxide, active zinc oxide and nano zinc oxide.

[0054] The softening oil includes a mixture of one or more of naphthenic oil, heavy naphthenic oil and environmentally friendly aromatic oil.

[0055] The wear-resistant rubber formula of the present application is composed of the following ingredients in parts by weight: 45-65 parts of styrene-butadiene rubber, 35-55 parts of halogenated butyl rubber, 65-75 parts of carbon black, 1.5-2.5 parts of stearic acid, 2.5-4.5 parts of zinc oxide, 1-2 parts of antioxidant RD, 2-3 parts of antioxidant (4020), 1-2 parts of protective wax, 4-8 parts of softening oil, 3-5 parts of tackifying resin, 3-5 parts of hydrocarbon resin mixture, 1-1.5 parts of light magnesium oxide, 1-1.5 parts of insoluble sulfur (OT20), 1-1.5 parts of accelerator NS, 0.8-1.2 parts of accelerator CZ, 0.25-0.45 parts of anti-scorch agent CTP, and 1.5-2.5 parts of hardening and reinforcing agent.

[0056] After further reduction, in the high air retention wear-resistant rubber formula for tubeless all-steel load-bearing radial tires of the present application, styrene-butadiene rubber is 50-60 parts, halogenated butyl rubber is 40-50 parts, carbon black is 65-70 parts, stearic acid is 1.5-2 parts, zinc oxide is 3-4 parts, antioxidant RD is 1-1.5 parts, antioxidant (4020) is 2.5-3 parts, protective wax is 1-1.5 parts, softening oil is 4-7 parts, tackifying resin is 4-5 parts, hydrocarbon resin mixture is 4-5 parts, light magnesium oxide is 1-1.5 parts, insoluble sulfur (OT20) is 1.0-1.5 parts, accelerator NS is 1-1.5 parts, accelerator CZ is 0.8-1 parts, anti-scorch agent CTP is 0.3-0.4 parts, and hardening and reinforcing agent is 2-2.5 parts.

[0057] Specifically, in Example 1, the wear-resistant rubber formula of the present application is composed of the following ingredients in parts by weight: 45 parts of styrene-butadiene rubber, 35 parts of halogenated butyl rubber, 65 parts of carbon black, 1.5 parts of stearic acid, 2.5 parts of zinc oxide, 1 part of antioxidant RD, 2 parts of antioxidant (4020), 1 part of protective wax, 4 parts of softening oil, 3 parts of tackifying resin, 3 parts of hydrocarbon resin mixture, 1 part of light magnesium oxide, 1 part of insoluble sulfur (OT20), 1 part of accelerator NS, 0.8 parts of accelerator CZ, 0.25 parts of anti-scorch agent CTP, and 1.5 parts of hardening and reinforcing agent.

[0058] In Example 2, the wear-resistant rubber formula of the present application is composed of the following ingredients in parts by weight: 65 parts of styrene-butadiene rubber, 55 parts of halogenated butyl rubber, 75 parts of carbon black, 2.5 parts of stearic acid, 4.5 parts of zinc oxide, 2 parts of antioxidant RD, 3 parts of antioxidant (4020), 2 parts of protective wax, 8 parts of softening oil, 5 parts of tackifying resin, 5 parts of hydrocarbon resin mixture, 1.5 parts of light magnesium oxide, 1.5 parts of insoluble sulfur (OT20), 1.5 parts of accelerator NS, 1.2 parts of accelerator CZ, 0.45 parts of anti-scorch agent CTP, and 2.5 parts of hardening and reinforcing agent.

[0059] In Example 3, the wear-resistant rubber formula of the present application is composed of the following ingredients in parts by weight: 57 parts of styrene-butadiene rubber, 42 parts of halogenated butyl rubber, 66 parts of carbon black, 1.8 parts of stearic acid, 3.2 parts of zinc oxide, 1.5 parts of antioxidant RD, 2.3 parts of antioxidant (4020), 1.4 parts of protective wax, 7 parts of softening oil, 4 parts of tackifying resin, 4 parts of hydrocarbon resin mixture, 1.2 parts of light magnesium oxide, 1.4 parts of insoluble sulfur (OT20), 1.4 parts of accelerator NS, 0.9 parts of accelerator CZ, 0.33 parts of anti-scorch agent CTP, and 1.9 parts of hardening and reinforcing agent.

[0060] The present application also includes a method for preparing the above-mentioned radial tire wear-resistant rubber, comprising the following steps:

[0061] 1) Weigh the ingredients of the wear-resistant rubber formula for radial truck tires according to the proportion of ingredients;

[0062] 2) preparing a rubber mix; adding halogenated butyl rubber, tackifying resin, hydrocarbon resin mixture, light magnesium oxide, and part of carbon black into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain a masterbatch; the weight of the carbon black added in this step is 60% of the weight of the halogenated butyl rubber;

[0063] 3) preparing a second-stage masterbatch; adding the first-stage masterbatch, styrene-butadiene rubber, antioxidant RD, antioxidant 4020, protective wax and the remaining carbon black into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain a second-stage masterbatch;

[0064] 4) preparing a three-stage masterbatch; adding the second-stage masterbatch into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain a three-stage masterbatch;

[0065] 5) preparing the final rubber mix; adding the three-stage masterbatch, zinc oxide, insoluble sulfur OT20, accelerator NS, accelerator CZ, hardening and reinforcing agent, and anti-scorching agent CTP into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain the final rubber mix.

[0066] In step 2), the speed of the internal mixer is adjusted to 45 rpm, the upper push bolt pressure is 0.45-0.55 MPa, and the push bolt is pressed and mixed for 30 seconds;

[0067] Raise the top bolt, add softened oil into the internal mixer, press the top bolt, and mix for 20 seconds;

[0068] Lift the top bolt for cleaning, press the top bolt for mixing for 20 seconds, open the discharge door to discharge glue, control the discharge temperature at 140-150℃, and extrude the next sheet through the extruder;

[0069] In step 3), the speed of the internal mixer was adjusted to 45 rpm, the upper push bolt pressure was 0.45-0.55 MPa, and the push bolt was pressed and mixed for 25 seconds;

[0070] Lift the top bolt for cleaning, adjust the speed of the internal mixer to 40rpm, press the top bolt and mix for 30 seconds, open the discharge door to discharge the glue, control the discharge temperature at 145-150℃, and extrude the next sheet with the extruder;

[0071] In step 4), the speed of the internal mixer was adjusted to 40 rpm, the upper push bolt pressure was 0.45-0.55 MPa, and the push bolt was pressed and mixed for 25 seconds;

[0072] Lift the top bolt for cleaning for 5 seconds, press the top bolt for mixing for 30 seconds, open the discharge door to discharge glue, control the discharge temperature at 140-150℃, and extrude the next sheet through the extruder;

[0073] In step 5), the speed of the internal mixer was adjusted to 26 rpm, and the top bolt was pressed and mixed for 25 seconds;

[0074] Raise the top plug for cleaning for 5 seconds, press the top plug for mixing for 25 seconds;

[0075] Raise the top bolt, press the top bolt and mix for 25 seconds, raise the top bolt, open the discharge door to discharge the glue, control the discharge temperature at 95-105℃, open the mixing mill to unload the sheets, cool and build stacks.

[0076] The technical solution of the present application is further described below in conjunction with a specific rubber compound formulation and preparation method.

[0077] Comparative formula of common wear-resistant rubber

[0078] According to weight, weigh 50 parts of natural rubber (STR20), 50 parts of butadiene rubber (BR9000), 0.2 parts of peptizer (P40), 80 parts of carbon black (N330), 2 parts of stearic acid, 3.5 parts of indirect zinc oxide, 3 parts of octylphenol formaldehyde tackifying resin, 3.0 parts of cyclohexane oil, 2.75 parts of antioxidant (4020), 0.5 parts of protective wax, 0.90 parts of accelerator NS, 2.5 parts of insoluble sulfur (OT20), and 0.4 parts of scorch retarder CTP.

[0079] Formula 1 of the present invention

[0080] The components for preparing a high air retention wear-resistant rubber formula for tubeless all-steel load-bearing radial tires were weighed according to the proportion of each component: 55 parts of styrene-butadiene rubber (SBR1502), 45 parts of chlorinated butyl rubber (CIIR-1301), 68 parts of carbon black (N234), 2 parts of stearic acid, 3.5 parts of indirect zinc oxide, 1 part of antioxidant RD, 2.5 parts of antioxidant (4020), 1 part of protective wax, 5 parts of cyclohexane oil, 4 parts of octylphenol formaldehyde tackifying resin, 4 parts of hydrocarbon resin mixture, 1 part of light magnesium oxide, 1.25 parts of insoluble sulfur (OT20), 1.2 parts of accelerator NS, 1 part of accelerator CZ, 0.3 parts of scorch retarder CTP, and 2 parts of hardening and reinforcing agent (8180).

[0081] Formula 2 of the present invention

[0082] The components for preparing a high air retention wear-resistant rubber formula for tubeless all-steel load-bearing radial tires were weighed according to the proportion of each component: 50 parts of styrene-butadiene rubber (SBR1502), 50 parts of chlorinated butyl rubber (CIIR-1301), 70 parts of carbon black (N234), 2.0 parts of stearic acid, 3.5 parts of indirect zinc oxide, 1 part of antioxidant RD, 2.5 parts of antioxidant (4020), 1 part of protective wax, 5 parts of cyclohexane oil, 5 parts of octylphenol formaldehyde tackifying resin, 4 parts of hydrocarbon resin mixture, 1 part of light magnesium oxide, 1.25 parts of insoluble sulfur (OT20), 1.2 parts of accelerator NS, 1.0 parts of accelerator CZ, 0.3 parts of scorch retarder CTP, and 2 parts of hardening and reinforcing agent (8180).

[0083] Prepare the above two formulations: formulation 1 of the present invention and formulation 2 of the present invention, and prepare the rubber material according to the following steps.

[0084] (1) According to the composition ratio, weigh the components of the high air retention wear-resistant rubber formula for tubeless all-steel radial truck tires respectively;

[0085] (2) One-stage mixing: add chlorinated butyl rubber, tackifying resin, hydrocarbon resin mixture, light magnesium oxide, and part of carbon black to an internal mixer, adjust the mixer speed to 45 rpm, set the upper push pin pressure to 0.45-0.55 MPa, press the push pin and mix for 30 seconds; raise the push pin, add cyclohexane oil to the internal mixer, press the push pin, and mix for 20 seconds; raise the push pin for cleaning, press the push pin and mix for 20 seconds; open the discharge door to discharge the rubber, and control the discharge temperature to 140-150°C; extrude the next sheet through the extruder, cool and stack; the weight of the carbon black added in this step is 60% of the weight of the halogenated butyl rubber

[0086] (3) Second stage mixing: add the first stage masterbatch, styrene-butadiene rubber, antioxidant RD, antioxidant 4020, protective wax and the remaining carbon black into the internal mixer, adjust the speed of the internal mixer to 45 rpm, set the upper top bolt pressure to 0.45-0.55 MPa, press the top bolt and mix for 25 seconds; raise the top bolt for cleaning, adjust the speed of the internal mixer to 40 rpm, press the top bolt and mix for 30 seconds; open the discharge door to discharge the rubber, and control the discharge temperature to 145-150°C; extrude the next sheet through the extruder, cool it and build a stack;

[0087] (4) Three-stage mixing: Add the second-stage masterbatch into the internal mixer, adjust the speed of the internal mixer to 40 rpm, set the upper plug pressure to 0.45-0.55 MPa, press the upper plug to mix for 25 seconds; raise the upper plug to clean for 5 seconds, press the upper plug to mix for 30 seconds; open the discharge door to discharge the rubber, and control the discharge temperature to 140-150 ° C; extrude the next piece through the extruder, cool it and build a stack;

[0088] (5) Final rubber mixing: Add three-stage masterbatch, indirect zinc oxide, insoluble sulfur OT20, accelerator NS, accelerator CZ, hardening and reinforcing agent 8180, and anti-scorching agent CTP into the internal mixer, adjust the speed of the internal mixer to 26 rpm, press the top bolt and mix for 25 seconds; raise the top bolt to clean for 5 seconds, press the top bolt and mix for 25 seconds; raise the top bolt, press the top bolt and mix for 25 seconds, raise the top bolt, open the unloading door to discharge the rubber, and control the discharge temperature at 95-105°C; open the mixer to unload the sheets, cool and stack.

[0089] The performance test of the mixed rubber after vulcanization prepared by the high air retention and wear-resistant rubber formula of the tubeless all-steel load-bearing radial tire of the present application.

[0090] The physical property tests were carried out on the ordinary sub-mouth wear-resistant rubber comparison formula, the ordinary sub-mouth wear-resistant rubber prepared by the formula one of the present invention and the formula two of the present invention, and the sub-mouth wear-resistant rubber of the present invention under the same vulcanization conditions, and the performance values ​​of the sub-mouth wear-resistant rubber were detected. The test results are shown in Tables 1 to 4 below.

[0091] Table 1

[0092] Curing conditions: 150℃*30min Comparison formula Formula 1 of the present invention Formula 2 of the present invention Tensile strength MPa 18.57 16.54 16.68 Elongation at break % 305 350 365 100% fixed elongation MPa 4.45 3.82 3.79 200% elongation MPa 11.44 9.85 9.55 300% elongation MPa 18.26 14.98 14.68 Hardness(Shore A) 74 73 73 Right angle tear strength KN / m 50.2 55.5 53.6 Density g / cm3 1.169 1.160 1.165

[0093] Table 2

[0094] Aging conditions: 100℃*48h Comparison formula Formula 1 of the present invention Formula 2 of the present invention Tensile strength MPa 13.05 14.50 14.90 Elongation at break % 142 256 270 100% fixed elongation MPa 8.6 5.56 5.62 200% elongation MPa - 11.75 11.82 Hardness(Shore A) 80 79 79 Right angle tear strength KN / m 35.5 44.8 43.6 Aging resistance coefficient 0.3272 0.6412 0.6608 Aging resistance coefficient% 100.0 195.96 201.95

[0095]

[0096] Table 3

[0097]

[0098] Table 4

[0099]

[0100] It can be seen from Tables 1 to 4 that the high air retention bead wear-resistant rubber of the tubeless all-steel load-bearing radial tire prepared by the technical solution of the present application has a similar hardness, an aging resistance coefficient increased by 95.96-101.95%, a permeability coefficient reduced by 79.20-81.07%, and an anti-vulcanization reversion property increased by more than 92.86%; the aging air retention test of the finished tire shows that the tire air retention and aging resistance are significantly improved; This shows that the formula rubber of the present invention can greatly reduce the anti-vulcanization reversion property, aging resistance, and tire air retention, thereby avoiding tire failures caused by aging and poor air retention at the bead, and providing protection for customers' driving safety.

[0101] It should be noted that the following is the research and development ideas and mechanism of action of the high air retention wear-resistant rubber of the tubeless all-steel load-bearing radial tire of this application.

[0102] Through a lot of research, it is found that the reasons why the existing wear-resistant rubber for the sub-mouth has poor air retention and aging resistance are as follows:

[0103] 1. The raw rubber in the existing wear-resistant rubber formula is made of natural rubber and butadiene rubber. Since natural rubber and butadiene rubber have high unsaturation, high unsaturated double bond content, and good molecular chain flexibility, they are not good for gas barrier properties and heat-oxidative aging resistance. Among the common raw rubbers in the rubber industry, butyl rubber has the best air tightness and aging resistance, followed by styrene-butadiene rubber, both of which are better than butadiene rubber and natural rubber. The choice of raw rubber variety has a crucial impact on the air tightness and aging resistance of the rubber compound;

[0104] 2. The existing formula protection system of the wear-resistant rubber of the sub-mouth is a combination of antioxidant 4020 and protective wax. It lacks antioxidant RD with good thermal oxidative aging, which is not good for thermal oxidative aging. The amount of protective wax is small, which is not good for physical protection against ozone.

[0105] 3. The existing wear-resistant rubber formula vulcanization system adopts ordinary sulfur vulcanization system, and the cross-linking bonds are mainly polysulfide bonds, which have poor resistance to heat and oxygen aging. Among the chemical cross-linking bonds, polysulfide bonds have the lowest bond energy and are easily damaged.

[0106] 4. The existing reinforcement system of the wear-resistant rubber formula of the sub-mouth adopts N330 carbon black with small specific surface area and large particle size for reinforcement, which has poor reinforcement, low tear strength and poor damage resistance;

[0107] In view of the above-mentioned technical problems existing in the existing bead wear-resistant rubber, the inventors have developed a high air-retaining bead wear-resistant rubber formula for tubeless all-steel load-bearing radial tires of the present invention. The present invention significantly improves the air tightness and aging resistance of the bead wear-resistant rubber, ensures the air retention and aging resistance of the tire bead position, and improves the driving safety of the vehicle.

[0108] The mechanism by which the high air retention and wear-resistant rubber formula for tubeless all-steel radial truck tires of the present application significantly improves air retention and aging resistance is as follows:

[0109] 1. The formula of this application cancels the use of natural rubber and butadiene rubber, and uses styrene-butadiene rubber and halogenated butyl rubber with good air tightness and aging resistance to increase the air tightness and aging resistance of the raw rubber itself;

[0110] The gas filled inside the tubeless all-steel radial tire is generally air, and the oxygen content in the air is about 21%. Its penetration will cause oxidation and aging of the wear-resistant rubber at the tip and other parts of the tire, thus damaging the tire. The diffusion coefficient of oxygen in different rubbers is different, natural rubber is 1.6, butadiene rubber is 1.5, styrene butadiene rubber is 1.4, and butyl rubber is 0.08. From the perspective of oxygen diffusion coefficient, eliminating natural rubber and butadiene rubber and replacing them with styrene butadiene rubber and halogenated butyl rubber can greatly improve air tightness and aging resistance. Because halogenated butyl rubber has high saturation, it has the same air tightness and aging resistance as butyl rubber, and has better compatibility with other general-purpose rubbers.

[0111] 2. The formula of the present application improves heat-oxidative aging resistance and ozone protection by increasing the variety of antioxidant RD and adjusting the dosage of antioxidant 4020 and protective wax. Due to the combination of antioxidant RD with good heat-aging resistance, antioxidant 4020 with good oxygen and ozone aging resistance, and protective wax with ozone-resistant physical antioxidant, the comprehensive aging resistance of the protective system can be significantly improved;

[0112] 3. Rubber aging is mainly reflected in the breakage of rubber molecular chains and vulcanization cross-links. Among them, the vulcanization cross-links are divided into carbon-carbon bonds, monosulfide bonds, disulfide bonds, and polysulfide bonds, and their bond energies are 360, 270, 220, and 120 KJ / mol, respectively. Carbon-carbon bonds and monosulfide bonds have high bond energies and are not easy to break. The current formula of the wear-resistant rubber is a common vulcanization system, and the cross-links are mainly polysulfide bonds, resulting in poor aging resistance. In order to improve aging resistance, the formula of this application introduces halogenated butyl rubber, uses zinc oxide, a low amount of sulfur vulcanizing agent and a high amount of accelerator, and the vulcanization cross-links formed are mainly carbon-carbon cross-links and monosulfide bonds, which greatly improves the aging resistance of the rubber.

[0113] 4. The formula of this application can achieve the same modulus by adding a modulus enhancer to reduce the amount of carbon black used, which can reduce heat generation. It uses high-structure, high-specific surface area carbon black N234 to improve the tensile properties, hardness and modulus of the fully synthetic rubber mouth wear-resistant rubber, and reduce stress deformation of the tire bead;

[0114] It should be noted that, based on the research and development of the formula, in order to further improve the air retention and aging resistance of the high air retention and wear-resistant rubber of the tubeless all-steel load-bearing radial tire of the present invention, the mixing process is optimized. This is also the key to the high air retention of the high air retention and wear-resistant rubber formula of the tubeless all-steel load-bearing radial tire of the present application.

[0115] Through research, it is found that the high air retention and wear-resistant rubber formula of the tubeless all-steel load-bearing radial tire of the present application is composed of two raw rubbers, halogenated butyl rubber and styrene-butadiene rubber. The affinity of carbon black in different raw rubbers is different. Since styrene-butadiene rubber has fewer side groups than halogenated butyl rubber, the flexibility of the molecular chain is good, and the degree of unsaturation is large, carbon black is most easily mixed into the styrene-butadiene rubber phase, while halogenated butyl rubber contains a large number of side methyl groups and has poor flexibility of the molecular chain, so carbon black is difficult to disperse in the halogenated butyl rubber phase; this phenomenon of uneven distribution of carbon black is called "segregation" in the industry, and segregation will lead to poor performance of the rubber compound and uneven stress distribution. For the invention formula, it will also lead to a decrease in air tightness;

[0116] In order to solve the problem of carbon black "segregation", this application optimizes the process as follows:

[0117] 1. In the first stage of rubber compound mixing, halogenated butyl rubber, tackifying resin, hydrocarbon resin mixture, light magnesium oxide, 60% of the weight of halogenated butyl rubber carbon black, and softening oil are mixed. The reason for this step is that the carbon black is first mixed with the halogenated butyl rubber to strengthen the distribution of the carbon black in the halogenated butyl rubber phase and reduce the "segregation" problem of the carbon black;

[0118] 2. Add the first-stage masterbatch, styrene-butadiene rubber, antioxidant RD, antioxidant 4020, protective wax and the remaining carbon black to the second-stage mixing rubber. Delaying the addition of styrene-butadiene rubber can reduce the distribution of carbon black in the styrene-butadiene rubber phase. Adding the antioxidant in the second stage can reduce the weight loss caused by multiple mixing.

[0119] 3. The three-stage rubber compound is mixed for re-refining, and the three-stage masterbatch, indirect zinc oxide, insoluble sulfur OT20, accelerator NS, accelerator CZ, hardening and reinforcing agent 8180, and anti-scorch agent CTP are added in the final refining. The indirect zinc oxide and hardening and reinforcing agent are added in the final refining to avoid early crosslinking when the masterbatch is added.

[0120] The present application optimizes the process as described above to make the dispersion of the rubber, filler and chemical materials more uniform, thereby improving the air tightness of the rubber and enhancing the aging resistance.

[0121] The present application provides a high-air-retaining wear-resistant rubber formula and preparation method for tubeless all-steel load-bearing radial tires, which have the following beneficial effects: by eliminating the use of natural rubber and butadiene rubber with poor air tightness and poor aging resistance in the raw rubber system, and replacing them with styrene-butadiene rubber and halogenated butyl rubber with good air tightness and aging resistance, the air tightness and aging resistance of the main body of the formula are improved; by using three antioxidants, RD, 4020, and protective wax, the comprehensive protective performance of the formula protection system, such as resistance to ozone, thermal oxygen, and fatigue, is improved; by using zinc oxide and low sulfur and high accelerator dosage, an effective vulcanization system is formed to improve the aging resistance of the vulcanization system; by using modulus enhancers and high specific surface area carbon black, the tensile properties, hardness and modulus of the fully synthetic rubber wear-resistant rubber are improved, and the stress deformation of the tire bead portion is reduced; the present invention optimizes the process to make the fillers and chemical materials more evenly distributed in different raw rubbers, thereby improving the aging resistance and air tightness of the rubber.

[0122] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A wear-resistant rubber for radial load tire, characterized by: It is composed of the following ingredients in parts by weight: 80-120 parts of raw rubber composition, 65-75 parts of carbon black, 1.5-2.5 parts of stearic acid, 2.5-4.5 parts of zinc oxide, 3-5 parts of antioxidant composition, 1-2 parts of protective wax, 4-8 parts of softening oil, 6-10 parts of resin mixture, 1-1.5 parts of light magnesium oxide, 1-1.5 parts of insoluble sulfur, 1.8-2.7 parts of accelerator mixture, 0.25-0.45 parts of anti-scorch agent CTP, and 1.5-2.5 parts of hardening and reinforcing agent.

2. The wear-resistant rubber for radial truck tire according to claim 1, characterized in that: It is composed of the following ingredients in parts by weight: 90-110 parts of raw rubber composition, 65-70 parts of carbon black, 1.5-2 parts of stearic acid, 3-4 parts of zinc oxide, 3.5-4.5 parts of antioxidant composition, 1-1.5 parts of protective wax, 4-7 parts of softening oil, 8-10 parts of resin mixture, 1-1.5 parts of light magnesium oxide, 1-1.5 parts of insoluble sulfur, 1.8-2.5 parts of accelerator mixture, 0.3-0.4 parts of anti-scorch agent CTP, and 2-2.5 parts of hardening and reinforcing agent.

3. The wear-resistant rubber for radial truck tire according to claim 1, characterized in that: It is composed of the following ingredients in parts by weight: 100 parts of raw rubber composition, 68 parts of carbon black, 2 parts of stearic acid, 3.5 parts of zinc oxide, 3.5 parts of antioxidant composition, 1 part of protective wax, 5 parts of softening oil, 8 parts of resin mixture, 1 part of light magnesium oxide, 1.25 parts of insoluble sulfur, 2.2 parts of accelerator mixture, 0.3 parts of anti-scorch agent CTP, and 2 parts of hardening and reinforcing agent.

4. The wear-resistant rubber for radial truck tire according to claim 1, characterized in that: It is composed of the following ingredients in parts by weight: 100 parts of raw rubber composition, 70 parts of carbon black, 2 parts of stearic acid, 3.5 parts of zinc oxide, 3.5 parts of antioxidant composition, 1 part of protective wax, 5 parts of softening oil, 9 parts of resin mixture, 1 part of light magnesium oxide, 1.25 parts of insoluble sulfur, 2.2 parts of accelerator mixture, 0.3 parts of anti-scorch agent CTP, and 2 parts of hardening and reinforcing agent.

5. The wear-resistant rubber for radial truck tire according to claim 1, characterized in that: The raw rubber in the raw rubber composition is a raw rubber system that does not contain natural rubber, and the raw rubber composition includes styrene-butadiene rubber and halogenated butyl rubber; The styrene butadiene rubber includes one or a mixture of two of emulsion polymerized styrene butadiene rubber SBR1502 and SBR1500; the halogenated butyl rubber includes chlorinated butyl rubber, and the chlorinated butyl rubber includes a mixture of one or more of high Mooney viscosity, medium Mooney viscosity, and low Mooney viscosity chlorinated butyl rubber.

6. The wear-resistant rubber for radial truck tire according to claim 1, characterized in that: The carbon black is one of N234 or N220 carbon black or a mixture of both; The hardening and reinforcing agent includes hardening and reinforcing agent 8180, and hardening and reinforcing agent 8180 is a bismaleimide derivative.

7. The wear-resistant rubber for radial truck tire according to claim 1, characterized in that: The accelerators include accelerator NS and accelerator CZ; The antioxidant composition includes antioxidant RD and antioxidant 4020; The resin mixture includes a tackifying resin and a hydrocarbon resin mixture; the tackifying resin includes one or a mixture of two of octylphenol formaldehyde tackifying resin and tert-butylphenol formaldehyde tackifying resin.

8. The wear-resistant rubber for radial truck tire according to claim 1, characterized in that: The zinc oxide is a mixture of one or more of indirect zinc oxide, active zinc oxide and nano zinc oxide; The softening oil includes a mixture of one or more of naphthenic oil, heavy naphthenic oil and environmentally friendly aromatic oil.

9. A method for preparing the wear-resistant rubber for the radial tire according to any one of claims 1 to 8, characterized in that: The following steps are involved: 1) Weigh the ingredients of the wear-resistant rubber formula for radial truck tires according to the proportion of ingredients; 2) preparing a rubber mix; adding halogenated butyl rubber, tackifying resin, hydrocarbon resin mixture, light magnesium oxide, and part of carbon black into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain a masterbatch; the weight of the carbon black added in this step is 60% of the weight of the halogenated butyl rubber; 3) preparing a second-stage masterbatch; adding the first-stage masterbatch, styrene-butadiene rubber, antioxidant RD, antioxidant 4020, protective wax and the remaining carbon black into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain a second-stage masterbatch; 4) preparing a three-stage masterbatch; adding the second-stage masterbatch into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain a three-stage masterbatch; 5) preparing the final rubber mix; adding the three-stage masterbatch, zinc oxide, insoluble sulfur OT20, accelerator NS, accelerator CZ, hardening and reinforcing agent, and anti-scorching agent CTP into an internal mixer for mixing; then, extruding the lower sheet through an extruder to obtain the final rubber mix.

10. The method for preparing the wear-resistant rubber for radial truck tire according to claim 9, characterized in that: In step 2), the speed of the internal mixer is adjusted to 45 rpm, the upper push bolt pressure is 0.45-0.55 MPa, and the push bolt is pressed and mixed for 30 seconds; Raise the top bolt, add softened oil into the internal mixer, press the top bolt, and mix for 20 seconds; Lift the top bolt for cleaning, press the top bolt for mixing for 20 seconds, open the discharge door to discharge glue, control the discharge temperature at 140-150℃, and extrude the next sheet through the extruder; In step 3), the speed of the internal mixer was adjusted to 45 rpm, the upper push bolt pressure was 0.45-0.55 MPa, and the push bolt was pressed and mixed for 25 seconds; Lift the top bolt for cleaning, adjust the speed of the internal mixer to 40rpm, press the top bolt and mix for 30 seconds, open the discharge door to discharge the glue, control the discharge temperature at 145-150℃, and extrude the next sheet with the extruder; In step 4), the speed of the internal mixer was adjusted to 40 rpm, the upper push bolt pressure was 0.45-0.55 MPa, and the push bolt was pressed and mixed for 25 seconds; Lift the top bolt for cleaning for 5 seconds, press the top bolt for mixing for 30 seconds, open the discharge door to discharge glue, control the discharge temperature at 140-150℃, and extrude the next sheet through the extruder; In step 5), the speed of the internal mixer was adjusted to 26 rpm, and the top bolt was pressed and mixed for 25 seconds; Raise the top plug for cleaning for 5 seconds, press the top plug for mixing for 25 seconds; Raise the top bolt, press the top bolt and mix for 25 seconds, raise the top bolt, open the discharge door to discharge the glue, control the discharge temperature at 95-105℃, open the mixing mill to unload the sheets, cool and build stacks.

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