Steel cord rubber composition containing a hydrazide compound and a method for preparing and using the same

Abstract

This invention belongs to the field of rubber materials technology, specifically relating to a steel cord rubber composition containing an acylhydrazine compound, its preparation method, and its application. The steel cord rubber composition containing an acylhydrazine compound, by weight, comprises the following components: 100 parts natural rubber, 30-60 parts carbon black, 1-40 parts silica, 5-15 parts zinc oxide, 0-2 parts cobalt borylate, 1-3 parts resorcinol, 2-10 parts binder, 3-8 parts insoluble sulfur, 0.5-3 parts accelerator, 0.5-4 parts antioxidant, and 0.5-4 parts acylhydrazine compound. This invention significantly reduces the rate of decline in rubber adhesive performance, especially under high temperature and long-term use conditions, and solves the problem of aging stability at the steel wire-rubber interface, reducing the release of Fe from the steel cord due to long-term heat accumulation in the rubber. 3+ and Cu 2+ The effects of metal ions are particularly applicable to all-steel radial truck tires.

Description

Technical Field

[0001] This invention belongs to the field of rubber materials technology, specifically relating to a steel wire cord rubber composition containing an acylhydrazine compound, its preparation method, and its application. Background Technology

[0002] Radial truck tires are a type of radial tire primarily used on heavy-duty vehicles and construction machinery. They have a complex structure with carcass cords arranged in a radial direction, using high-strength steel wires. Compared to ordinary fiber cords, copper-plated steel cords have higher tensile strength, rigidity, and stronger adhesion to rubber, enabling them to withstand greater loads. However, the adhesion strength between the steel cords and rubber is a key factor affecting tire durability. During long-term use, due to uneven load distribution, periodic deformation, and heat generation, the adhesion between the steel wires and rubber gradually decreases, leading to delamination or peeling. Especially at the exposed cut surfaces of the steel wire ends without copper plating, under high-temperature conditions (>80℃), the steel cords release Fe³⁺. + and Cu² + Metal ions, such as those present in the tire, can negatively impact tire performance, such as reducing the adhesion between rubber and steel wires and accelerating rubber aging.

[0003] To delay rubber aging and reduce the impact of metal ions on rubber properties, common techniques involve adding appropriate amounts of antioxidants (such as N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, abbreviated as 6PPD) and anti-aging agents to the rubber composition formulation. These antioxidants can effectively slow down the aging process of rubber, but traditional amine antioxidants (such as 6PPD) tend to migrate to metal surfaces, leading to their failure during long-term use and making it difficult to guarantee durability. Furthermore, to improve the initial adhesion between rubber and steel cord and reduce the loss of adhesion due to metal ions, specialized adhesive resins or tackifiers, such as resorcinol-formaldehyde-resin (RFL), are usually added to the rubber formulation. However, while these methods can improve the initial adhesion to some extent, they are insufficient to significantly reduce the rate of decline in rubber adhesive properties, especially under high temperature and long-term use conditions. Therefore, existing technologies still have shortcomings in addressing the aging stability problem of the steel wire-rubber interface. Summary of the Invention

[0004] The purpose of this invention is to provide a steel cord rubber composition containing hydrazide compounds, its preparation method and application, which improves the aging stability of the rubber-metal interface by adding hydrazide compounds.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides a steel cord rubber composition containing an acylhydrazine compound, comprising the following components by weight: 100 parts natural rubber, 30-60 parts carbon black, 1-40 parts silica, 5-15 parts zinc oxide, 0-2 parts cobalt borate, 1-3 parts resorcinol, 2-10 parts adhesive, 3-8 parts insoluble sulfur, 0.5-3 parts accelerator, 0.5-4 parts antioxidant, and 0.5-4 parts acylhydrazine compound;

[0007] The hydrazide-containing compound is one of oxodiazid, 1,2-bis(2-hydroxybenzoyl)hydrazide, 1-naphthoyl hydrazide, and a compound having the general formula I.

[0008] The structure of the compound having general formula I is shown below:

[0009]

[0010] General Formula I

[0011] Wherein, R is selected from one or more of the following groups from C1 to C10: alkyl, carbonyl, hydroxyl, carboxyl, aldehyde, amino, and naphthyl.

[0012] In some other embodiments, the composition comprises, by weight, the following components: 100 parts natural rubber, 40-50 parts carbon black, 5-15 parts silica, 5-10 parts zinc oxide, 0.5-1.5 parts cobalt borylate, 1.5-2 parts resorcinol, 3-5 parts adhesive, 4-6 parts insoluble sulfur, 1-2 parts accelerator, 1-3 parts antioxidant, and 0.5-3.5 parts hydrazide-containing compound;

[0013] The acylhydrazine compound is one of oxaloyldihydrazine, 1,2-bis(2-hydroxybenzoyl)hydrazine, and 1-naphthoylhydrazine.

[0014] In some other embodiments, the composition comprises the following components by weight: 100 parts natural rubber, 45 parts carbon black, 10 parts silica, 8 parts zinc oxide, 1 part cobalt borate, 1.8 parts resorcinol, 3.5 parts adhesive, 5 parts insoluble sulfur, 1.5 parts accelerator, 2 parts antioxidant, and 2 parts hydrazide-containing compound.

[0015] The acylhydrazide compound is 1-naphthoylhydrazide.

[0016] In some other embodiments, the natural rubber includes natural rubber STR20 and natural rubber SVR3L;

[0017] The carbon black is one or more of carbon black N220, N326, N375 and N330;

[0018] Preferably, the carbon black is carbon black N220;

[0019] The silica contains ≥92.0 wt% silica, has a loss on heating at 105℃ of 5-6 wt%, a loss on ignition of ≤6.0 wt%, and a specific surface area of ​​175-195 m². 2 / g;

[0020] The zinc oxide is obtained by indirect zinc oxide production, wherein the zinc oxide content is ≥99.50 wt% and the specific surface area is 4-6 m². 2 / g;

[0021] Preferably, the acetone extract of the natural rubber STR20 is 1.5-3.2 wt%;

[0022] The acetone extract of the natural rubber SVR3L is 2.5-4.5 wt%.

[0023] In some other embodiments, the cobalt content in the borosilicate is 21-23 wt%;

[0024] The resorcinol content is ≥99.5 wt%, and the DSC melting point is 110.0-114.0℃;

[0025] The acetone-insoluble matter in the adhesive RA65 is 30-40 wt%, and the ash content at 850℃ is 30-35 wt%.

[0026] The insoluble sulfur is insoluble sulfur OT20, which has an oil content of 18-21 wt%, a total sulfur content of 88-82 wt%, a thermal reduction rate of ≤25%, and a DSC melting point of 125-140 ℃.

[0027] In some other embodiments, the accelerator is accelerator DZ, wherein the accelerator DZ contains ≥97 wt% oil-free sulfenamide and ≤0.5 wt% cyclohexane-insoluble matter.

[0028] The antioxidant is antioxidant 6PPD, and the content of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine in antioxidant 6PPD is ≥96.0wt%.

[0029] In a second aspect, the present invention provides a method for preparing the steel wire cord rubber composition containing hydrazine compounds as described in the first aspect, comprising the following steps:

[0030] (1) Add natural rubber, carbon black and zinc oxide into a mixer and mix to make a first-stage masterbatch M1;

[0031] (2) Add the first stage of masterbatch M1 to the internal mixer and mix, then add fumed silica, antioxidant, and cobalt borate, and continue mixing to make the second stage of masterbatch M2;

[0032] (3) Add the second-stage masterbatch M2 into the internal mixer and mix, then add resorcinol and continue mixing to make the third-stage masterbatch M3;

[0033] (4) Add the three-stage masterbatch M3, adhesive, insoluble sulfur and accelerator to the internal mixer and mix. Then add the hydrazine compound and continue mixing to make the final rubber.

[0034] In some other embodiments, in step (1), the speed of the internal mixer is 42-46 rpm, the pressure of the top bolt is 0.50-0.60 MPa, the water temperature in the mixing chamber is 30-40℃, the mixing time is 35-45s, and the discharge temperature is 150-165℃.

[0035] In step (2), the speed of the internal mixer is 30-35 rpm, the pressure of the top plug is 0.50-0.60 MPa, the water temperature in the mixing chamber is 30-40℃, the mixing time of the first-stage masterbatch M1 is 15-25 s, the mixing time is 35-45 s, and the discharge temperature is 150-160℃.

[0036] In step (3), the speed of the internal mixer is 30-35 rpm, the pressure of the top plug is 0.50-0.60 MPa, the water temperature in the mixing chamber is 30-40℃, the mixing time of the second-stage masterbatch rubber M2 is 15-25 s, the mixing time is 35-45 s, and the discharge temperature is 140-145℃.

[0037] In step (4), the speed of the internal mixer is 15-25 rpm, the pressure of the top bolt is 0.45-0.50 MPa, the water temperature in the mixing chamber is 25-35℃, the mixing time is 25-30 s, the mixing time continues for ≥30 s, and the discharge temperature is 100-110℃.

[0038] In some other embodiments, in steps (1), (2) and (3), after mixing, the rubber compound in the internal mixer is emptied into a twin-screw extruder for tableting, cooling and storage for later use.

[0039] The distance between the two rollers of the twin-screw extruder tablet press is set to 5-10cm, the roller temperature to 85-105℃, and the screw temperature to 75-95℃.

[0040] The cooling and resting period is 7-9 hours.

[0041] A method for preparing a steel wire cord rubber composition containing an acylhydrazine compound specifically includes the following steps:

[0042] (1) First stage masterbatch M1: The first stage masterbatch was made using a GK420 internal mixer; natural rubber STR20 / SVR3L, N220 carbon black, and zinc oxide were used as the first stage masterbatch materials; the internal mixer speed was 45 rpm, the top bolt pressure was 0.55 MPa, and the water temperature in the mixing chamber was controlled at 35±5℃.

[0043] Add the above materials to the internal mixer, press down the top bolt, and hold the pressure at the set value for 40 seconds.

[0044] Lift the top bolt and hold for 5 seconds;

[0045] Press the top bolt down until the rubber compound temperature reaches 150°C, then lift the top bolt upwards;

[0046] Press the top bolt and hold until the rubber compound temperature reaches 165°C, then empty the rubber compound from the internal mixer into the twin-screw extruder and tablet press.

[0047] The twin-screw extruder tablets press a section of masterbatch M1 into tablets, which are then cooled and left to stand for 8 hours for later use (parameter settings: the distance between the two rollers is set to 5cm to 10cm, the roller temperature is 95±10℃, and the screw temperature is 85±10℃).

[0048] (2) Second-stage masterbatch M2: The second-stage masterbatch is made using a GK420 internal mixer; the first-stage masterbatch M1, silica, antioxidant, and cobalt borate are the materials for the second-stage masterbatch M2; the internal mixer speed is 35 rpm, the top jack pressure is 0.55 MPa, and the water temperature in the mixing chamber is controlled at 35±5℃.

[0049] Add the masterbatch M1 to the internal mixer and press down the top plug until the pressure reaches the set value and hold for 20 seconds;

[0050] Lift the top plug and add silica and cobalt borate;

[0051] Press down the top bolt and hold for 40 seconds;

[0052] Lift the top bolt and hold for 5 seconds.

[0053] Press the top bolt until the material temperature in the internal mixer reaches 155°C, then drain the rubber compound from the internal mixer to the twin-screw extruder tablet press.

[0054] The twin-screw extruder tablets press the second stage of masterbatch M2 into tablets, cool and let them stand for 8 hours for later use (parameter settings: the distance between the two rollers is set to 5cm to 10cm, the roller temperature is 95±10℃, and the screw temperature is 85±10℃).

[0055] (3) Three-stage masterbatch M3: The three-stage masterbatch is made using a GK420 internal mixer; the two-stage masterbatch M2 and resorcinol are the materials for the three-stage masterbatch M3; the internal mixer speed is 35 rpm, the top jack pressure is 0.55 MPa, and the water temperature in the mixing chamber is controlled at 35±5℃.

[0056] Add the second-stage masterbatch rubber M2 to the internal mixer and press down the top plug until the pressure reaches the set value and holds for 20 seconds;

[0057] Lift the top plug and add resorcinol;

[0058] Press down the top bolt and hold for 40 seconds;

[0059] Lift the top bolt and hold for 5 seconds.

[0060] Press the top bolt until the material temperature in the internal mixer reaches 145°C, then drain the rubber compound from the internal mixer to the twin-screw extruder tablet press.

[0061] The twin-screw extruder tablets press the second stage of masterbatch M2 into tablets, cool and let them stand for 8 hours for later use (parameter settings: the distance between the two rollers is set to 5cm to 10cm, the roller temperature is 95±10℃, and the screw temperature is 85±10℃).

[0062] (4) Final rubber: The final rubber is made using a GK255 internal mixer; the three-stage masterbatch M3, adhesive RA65, insoluble sulfur, accelerator, and hydrazide compound are the materials for the final rubber; the internal mixer speed is 25 rpm / 15 rpm, the top jack pressure is 0.45 MPa, and the water temperature in the mixing chamber is controlled at 30±5℃.

[0063] Add the three-stage masterbatch M3, adhesive RA65, insoluble sulfur, and accelerator to the internal mixer, press down the top plug, and hold the pressure at the set value for 30 seconds.

[0064] Lift the top bolt and hold for 5 seconds;

[0065] Press the top bolt until the temperature reaches 90℃, then adjust the speed of the internal mixer to 15 rpm;

[0066] Lift the top plug and add the hydrazide compound;

[0067] Press the top bolt until the temperature reaches 105℃ and the final pressing time is ≥30 seconds. Then discharge the glue to the open mill for sheeting, which will be used for the production of cord fabric and film in the next process.

[0068] Thirdly, the present invention provides the application of the steel cord rubber composition containing hydrazine compounds described in the first aspect in heavy-duty radial tires.

[0069] The beneficial effects of this invention are:

[0070] This invention enhances the adhesion and oxidation resistance of rubber to steel wire through three mechanisms: metal chelation, free radical capture, and interfacial crosslinking. Specifically, hydrazine groups and Fe... 3+ The formation of stable five-membered ring complexes effectively inhibits the Fenton reaction, reduces the rate of metal-catalyzed oxidation, and enables Fe... 3+Concentration decreased. Simultaneously, the naphthalene ring conjugated system efficiently captures hydroxyl radicals and synergistically constructs a dual-mechanism antioxidant network with 6PPD. Furthermore, the hydrazine group reacts with rubber vulcanization intermediates to form CNS crosslinking bonds, improving the heat resistance of the rubber-steel wire bonding interface. Detailed Implementation

[0071] Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the invention. Specific conditions not specified in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Components whose manufacturers are not specified are all commercially available conventional products.

[0072] Among them, natural rubber STR20 (Guangken Rubber Group), natural rubber SVR3L (Vietnam Rubber Group), carbon black N220 (Jiangxi Black Cat Co., Ltd.), adhesive RA65 (Chongqing Jianfeng Haokang Chemical Co., Ltd.), insoluble sulfur OT20 (Shandong Yanggu Huatai Chemical Co., Ltd.), accelerator DZ (Shandong Shangshun Chemical Co., Ltd.), and antioxidant 6PPD (Shandong Shengao Chemical Co., Ltd.).

[0073] The properties of some of the raw materials used are as follows: acetone extract of natural rubber STR20 is 1.5-3.2 wt%; acetone extract of natural rubber SVR3L is 2.5-4.5 wt%.

[0074] Silica content ≥92.0 wt%, loss on heating (105℃) 5-6 wt%, loss on ignition ≤6.0 wt%, specific surface area 180±15 m² 2 / g;

[0075] The zinc oxide is produced by indirect method, with a zinc oxide content ≥99.50 wt% and a specific surface area of ​​5.0 ± 1.0 m². 2 / g;

[0076] The cobalt content of boronyl cobalt is 22.5 ± 0.7 wt%;

[0077] Resorcinol content ≥99.5 wt%, DSC melting point 110.0-114.0℃;

[0078] Adhesive RA65 contains 34.0 ± 2.5 wt% acetone-insoluble matter and 30-35 wt% ash (850℃).

[0079] The insoluble sulfur is OT20, with an oil content of 19.5±1.5%, a total sulfur content of 80.0±1.5 wt%, a thermal reduction rate of ≤25%, and a DSC melting point of 132.0±6.0℃.

[0080] Accelerator DZ, sulfenamide content (oil-free) ≥97 wt%, cyclohexane insoluble matter ≤0.5 wt%;

[0081] Antioxidant 6PPD, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine content ≥96.0 wt%.

[0082] To address the issue of excessive heat buildup in all-steel radial truck tires during load testing, and to reduce the release of Fe³⁺ from the steel cords due to long-term heat accumulation in the rubber, + and Cu² + To mitigate the influence of metal ions, this application presents a novel steel cord rubber formulation and manufacturing process for use in all-steel radial truck tires. The novel steel cord rubber formulation includes natural rubber, carbon black, silica, zinc oxide, cobalt borate, resorcinol, RA65 binder, insoluble sulfur, accelerator, antioxidant, and hydrazide compound. The following detailed description, in conjunction with specific embodiments, illustrates the content of this application:

[0083] Example 1

[0084] A steel wire cord rubber composition containing an acylhydrazine compound, comprising the following components by weight (as shown in Table 1):

[0085] 100 parts natural rubber (100 parts natural rubber STR20), 45 parts carbon black (N220 carbon black), 10 parts silica, 8 parts zinc oxide, 1 part cobalt borate, 1.8 parts resorcinol, 3.5 parts adhesive (RA65 adhesive), 5 parts insoluble sulfur (OT20 insoluble sulfur), 1.5 parts accelerator (DZ accelerator), 2 parts antioxidant (6PPD antioxidant), and 2 parts hydrazide-containing compounds (0 parts oxodiazid, 0 parts 1,2-bis(2-hydroxybenzoyl)hydrazine, 2 parts 1-naphthoyl hydrazine).

[0086] A method for preparing a steel wire cord rubber composition containing an acylhydrazine compound includes the following steps:

[0087] (1) Preparation of Masterbatch M1

[0088] Natural rubber, carbon black, and zinc oxide were used as raw materials for the first-stage masterbatch. A GK420 internal mixer was used to prepare the first-stage masterbatch compound. The internal mixer speed was 45 rpm, the top jack pressure was 0.55 MPa, and the water temperature in the mixing chamber was controlled at 35±5℃. The first-stage masterbatch raw material was added to the internal mixer, and the top jack was pressed down until the pressure reached the set value and held for 40 seconds. The top jack was then lifted and held for 5 seconds. The top jack was pressed down and held until the rubber compound temperature reached 150℃, and then the top jack was lifted up. The top jack was pressed down and held until the rubber compound temperature reached 165℃. The rubber compound in the internal mixer was then emptied into a twin-screw extruder. The first-stage masterbatch compound M1 was pressed into tablets in the twin-screw extruder and cooled for 8 hours for later use (parameter settings: the distance between the two rollers was set to 5cm~10cm, the roller temperature was 95±10℃, and the screw temperature was 85±10℃).

[0089] (2) Preparation of the second-stage masterbatch M2

[0090] The first-stage masterbatch M1, silica, antioxidant, and cobalt borylate were used as raw materials for the second-stage masterbatch M2. The second-stage masterbatch was prepared using a GK420 internal mixer at 35 rpm, with a top pressure of 0.55 MPa and a mixing chamber water temperature of 35±5℃. First-stage masterbatch M1 was added to the internal mixer, and the top pressure was lowered and held for 20 seconds until the set pressure was reached. The top pressure was then lifted, and silica and cobalt borylate were added. The top pressure was then lowered and held for 40 seconds. The top pressure was then raised and held for 5 seconds. The top pressure was then lowered until the material temperature in the internal mixer reached 155℃. The rubber compound in the internal mixer was then emptied into a twin-screw extruder. The twin-screw extruder was used to press and cool the second-stage masterbatch M2 into tablets, which were then left to stand for 8 hours for later use (parameter settings: roller distance 5cm~10cm, roller temperature 95±10℃, screw temperature 85±10℃).

[0091] (3) Preparation of three-stage masterbatch M3

[0092] The second-stage masterbatch M2 and resorcinol were used as raw materials for the third-stage masterbatch M3. The third-stage masterbatch was prepared using a GK420 internal mixer with a speed of 35 rpm, a top jack pressure of 0.55 MPa, and a water temperature of 35±5℃ in the mixing chamber.

[0093] Add the second-stage masterbatch rubber M2 to the internal mixer and press down the top plug until the pressure reaches the set value and hold for 20 seconds; lift the top plug and add resorcinol; press down the top plug and hold for 40 seconds; lift the top plug and hold for 5 seconds; press down the top plug until the material temperature in the internal mixer reaches 145℃, then drain the rubber material from the internal mixer to a twin-screw extruder; the twin-screw extruder presses the second-stage masterbatch rubber M2 into tablets, cools and stands for 8 hours for later use (parameter settings: the distance between the two rollers is set to 5cm~10cm, the roller temperature is 95±10℃, and the screw temperature is 85±10℃).

[0094] (4) Preparation of final rubber compound

[0095] The final rubber compound is prepared using three-stage masterbatch M3, adhesive RA65, insoluble sulfur, accelerator, and hydrazide compound as raw materials. A GK255 internal mixer is used at 25 rpm / 15 rpm, with a top plug pressure of 0.45 MPa and a mixing chamber water temperature controlled at 30±5℃. The three-stage masterbatch M3, adhesive RA65, insoluble sulfur, and accelerator are added to the internal mixer, and the top plug is pressed down until the pressure reaches the set value and held for 30 seconds. The top plug is then lifted and held for 5 seconds. The top plug is pressed down until the temperature reaches 90℃, and the internal mixer speed is adjusted to 15 rpm. The top plug is then lifted, the hydrazide compound is added, and the top plug is pressed down until the temperature reaches 105℃, with the final pressing time ≥30 seconds. The rubber is then discharged to an open mill for sheeting, for use in the next process of fabrication and sheet production.

[0096] Example 2

[0097] A steel cord rubber composition containing hydrazide compound, the composition of which is shown in Table 1 by weight, differs from that in Example 1 in that the natural rubber is 100 parts of natural rubber SVR3L; the other composition and preparation method are the same as in Example 1.

[0098] Example 3

[0099] A steel cord rubber composition containing an acylhydrazine compound, the composition of which is shown in Table 1 by weight, differs from that in Example 1 in that the natural rubber is composed of 50 parts of natural rubber STR20 and 50 parts of natural rubber SVR3L, and 2 parts of the acylhydrazine compound (2 parts of oxodiazid); the other composition and preparation method are the same as in Example 1.

[0100] Example 4

[0101] A steel cord rubber composition containing an acylhydrazine compound, the composition of which is shown in Table 1 by weight, differs from Example 3 in that it contains 2 parts of the acylhydrazine compound (2 parts of 1,2-bis(2-hydroxybenzoyl)hydrazine); the other composition and preparation method are the same as in Example 3.

[0102] Example 5

[0103] A steel cord rubber composition containing an acylhydrazine compound, the composition of which is shown in Table 1 by weight, differs from Example 3 in that it contains 0.5 parts of the acylhydrazine compound (0.5 parts of 1-naphthoylhydrazine); the other components and preparation methods are the same as in Example 3.

[0104] Example 6

[0105] A steel wire cord rubber composition containing an acylhydrazine compound, the composition of which is shown in Table 1 by weight, differs from Example 3 in that it contains 2 parts of an acylhydrazine compound (2 parts of 1-naphthoylhydrazine); the other components and preparation methods are the same as in Example 3.

[0106] Example 7

[0107] A steel cord rubber composition containing an acylhydrazine compound, the composition of which is shown in Table 1 by weight, differs from Example 3 in that it contains 3.2 parts of the acylhydrazine compound (1-naphthoylhydrazine 3.2 parts); the other components and preparation method are the same as in Example 3.

[0108] Comparative Example 1

[0109] A steel cord fabric rubber composition, the composition of which is shown in Table 1 by weight; the difference from Example 1 is that the natural rubber is composed of 50 parts of natural rubber STR20 and 50 parts of natural rubber SVR3L, without the addition of hydrazide-containing compounds, and the other components are the same as in Example 1.

[0110] In the preparation method, in step (4) the preparation of the final compound, the three-stage masterbatch M3, adhesive RA65, insoluble sulfur, and accelerator are used as raw materials for the final compound. The final compound is prepared using a GK255 internal mixer with a speed of 25 rpm / 15 rpm, a top plug pressure of 0.45 MPa, and a mixing chamber water temperature of 30±5℃. The three-stage masterbatch M3, adhesive RA65, insoluble sulfur, and accelerator are added to the internal mixer and the top plug is pressed down until the pressure reaches the set value and is held for 30 seconds; the top plug is lifted and held for 5 seconds; the top plug is pressed down until the temperature reaches 90℃, and the speed of the internal mixer is adjusted to 15 rpm; the top plug is lifted; the top plug is pressed down until the temperature reaches 105℃ and the final pressing time is ≥30 seconds, and the compound is discharged to the open mill for sheeting for the next process of fabric and sheet production.

[0111] Table 1. Composition of the steel cord fabric rubber composition in the examples and comparative examples.

[0112] Components / parts by weight Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Natural rubber (STR20) 50 100 0 50.00 50.00 50.00 50.00 50.00 Natural rubber (SVR3L) 50 0 100 50.00 50.00 50.00 50.00 50.00 Carbon black N220 45.00 45.00 45.00 45.00 45.00 45.00 45.00 45.00 precipitate 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 Zinc oxide 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 cobalt boronyl 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 resorcinol 1.80 1.80 1.80 1.80 1.80 1.80 1.80 1.80 Adhesive RA65 3.50 3.50 3.50 3.50 3.50 3.50 3.50 3.50 Insoluble sulfur OT20 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 Accelerator DZ 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 Anti-aging agent 6PPD 2 2 2 2 2 2 2 2 oxohydrazide 0 0 0 2 0 0 0 0 1,2-Bis(2-hydroxybenzoyl)hydrazine 0 0 0 0 2 0 0 0 1-Naphthoylhydrazine 0 2 2 0 0 0.5 2 3.2

[0113] Performance testing

[0114] 1. Tensile properties: Tested in accordance with GB / T528-2009.

[0115] 2. Tire durability performance evaluation: in accordance with GB / T 4501 Indoor test method for the performance of truck tires.

[0116] 3. Adhesion test: GB / T 3513-2018 "Determination of adhesion between vulcanized rubber and single steel wire - extraction method" was adopted.

[0117] In this study, the performance data of Comparative Example 1 and Examples 1-7 are expressed as exponents. The values ​​for constant elongation, tensile strength, elongation at break, adhesion, adhesion after heat aging, and durability of the finished tire in Comparative Example 1 are set to 100. For Examples 1-7, a higher value of 100 indicates better performance. The specific test results are shown in Table 2.

[0118] Table 2. Performance of the steel cord rubber composition in the examples and comparative examples.

[0119]

[0120] As can be seen from the results in Table 2, compared with Comparative Example 1, the rubber compositions of Examples 1-7, under the condition of comparable tensile strength, elongation at break, and stress at a given elongation, showed better performance at 100°C. The steel wires have better adhesion after 72 hours of aging, and the finished tires have better durability.

[0121] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A steel wire cord rubber composition containing an acylhydrazine compound, characterized in that, By weight, it comprises the following components: 100 parts natural rubber, 30-60 parts carbon black, 1-40 parts silica, 5-15 parts zinc oxide, 0.5-2 parts cobalt borylate, 1-3 parts resorcinol, 2-10 parts adhesive, 3-8 parts insoluble sulfur, 0.5-3 parts accelerator, 0.5-4 parts antioxidant, and 2-4 parts hydrazide-containing compound; The hydrazide-containing compound is 1-naphthoylhydrazide; The adhesive is RA65.

2. The steel wire cord rubber composition containing an acylhydrazine compound according to claim 1, characterized in that, By weight, it comprises the following components: 100 parts natural rubber, 40-50 parts carbon black, 5-15 parts silica, 5-10 parts zinc oxide, 0.5-1.5 parts cobalt borylate, 1.5-2 parts resorcinol, 3-5 parts adhesive, 4-6 parts insoluble sulfur, 1-2 parts accelerator, 1-3 parts antioxidant, and 2-3.5 parts hydrazide-containing compound; The acylhydrazide compound is 1-naphthoylhydrazide.

3. The steel wire cord rubber composition containing an acylhydrazine compound according to claim 1, characterized in that, By weight, it comprises the following components: 100 parts natural rubber, 45 parts carbon black, 10 parts silica, 8 parts zinc oxide, 1 part cobalt borate, 1.8 parts resorcinol, 3.5 parts adhesive, 5 parts insoluble sulfur, 1.5 parts accelerator, 2 parts antioxidant, and 2 parts hydrazide-containing compound. The acylhydrazide compound is 1-naphthoylhydrazide.

4. The hydrazide-containing compound steel cord rubber composition of claim 1, wherein, The natural rubber includes natural rubber STR20 and natural rubber SVR3L; The carbon black is one or more of carbon black N220, N375, N326 and N330; The silica contains ≥92.0 wt% silica, has a loss on heating at 105℃ of 5-6 wt%, a loss on ignition ≤6.0 wt%, and a specific surface area of ​​175-195 m². 2 / g; The zinc oxide is obtained by indirect zinc oxide production, wherein the zinc oxide content is ≥99.50 wt% and the specific surface area is 4-6 m². 2 / g; The acetone extract of the natural rubber SVR3L is 2.5-4.5 wt%.

5. The hydrazide-containing compound steel cord rubber composition according to claim 4, characterized in that, The acetone extract of the natural rubber STR20 is 1.5-3.2 wt%.

6. The steel wire cord rubber composition containing an acylhydrazine compound according to claim 1, characterized in that, The cobalt content in the boroyl cobalt is 21-23 wt%; The resorcinol content is ≥99.5 wt%, and the DSC melting point is 110.0-114.0℃; The acetone-insoluble matter in the adhesive RA65 is 30-40 wt%, and the ash content at 850℃ is 30-35 wt%. The insoluble sulfur is insoluble sulfur OT20, which has an oil content of 18-21 wt%, a total sulfur content of 88-82 wt%, a thermal reduction rate of ≤25%, and a DSC melting point of 125-140 ℃.

7. The steel wire cord rubber composition containing an acylhydrazine compound according to claim 1, characterized in that, The accelerator is accelerator DZ, wherein the accelerator DZ contains ≥97 wt% oil-free sulfenamide and ≤0.5 wt% cyclohexane-insoluble matter. The antioxidant is antioxidant 6PPD, and the content of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine in antioxidant 6PPD is ≥96.0wt%.

8. A method for preparing a steel wire cord rubber composition containing an acylhydrazine compound as described in any one of claims 1-7, characterized in that, Includes the following steps: (1) Add natural rubber, carbon black and zinc oxide into a mixer and mix to make a first-stage masterbatch M1; (2) Add the first stage of masterbatch M1 to the internal mixer and mix, then add fumed silica, antioxidant, and cobalt borate, and continue mixing to make the second stage of masterbatch M2; (3) Add the second-stage masterbatch M2 into the internal mixer and mix, then add resorcinol and continue mixing to make the third-stage masterbatch M3; (4) Add the three-stage masterbatch M3, adhesive, insoluble sulfur and accelerator to the internal mixer and mix. Then add the hydrazine compound and continue mixing to make the final rubber.

9. The method for preparing the steel wire cord rubber composition containing hydrazine compound according to claim 8, characterized in that, In step (1), the speed of the internal mixer is 42-46 rpm, the pressure of the top bolt is 0.50-0.60 MPa, the water temperature in the mixing chamber is 30-40℃, the mixing time is 35-45s, and the discharge temperature is 150-165℃. In step (2), the speed of the internal mixer is 30-35 rpm, the pressure of the top plug is 0.50-0.60 MPa, the water temperature in the mixing chamber is 30-40℃, the mixing time of the first-stage masterbatch M1 is 15-25 s, the mixing time is 35-45 s, and the discharge temperature is 150-160℃. In step (3), the speed of the internal mixer is 30-35 rpm, the pressure of the top plug is 0.50-0.60 MPa, the water temperature in the mixing chamber is 30-40℃, the mixing time of the second-stage masterbatch rubber M2 is 15-25 s, the mixing time is 35-45 s, and the discharge temperature is 140-145℃. In step (4), the speed of the internal mixer is 15-25 rpm, the pressure of the top plug is 0.45-0.50 MPa, the water temperature in the mixing chamber is 25-35℃, the mixing time is 25-30 s, the mixing time continues for ≥30 s, and the discharge temperature is 100-110℃.

10. The method for preparing the steel wire cord rubber composition containing an acylhydrazine compound according to claim 8, characterized in that, In steps (1), (2) and (3), after mixing, the rubber compound in the internal mixer is emptied into a twin-screw extruder for tableting, cooling and storage for later use. The distance between the two rollers of the twin-screw extruder tablet press is set to 5-10 cm, the roller temperature to 85-105℃, and the screw temperature to 75-95℃. The cooling and resting time is 7-9 hours.

11. The use of a steel cord rubber composition containing an acylhydrazine compound as described in any one of claims 1-7 in a heavy-duty radial tire.

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