Wirecord fabric rubber composition containing hydrazide compound as well as preparation method and application of wirecord fabric rubber composition

Abstract

The invention belongs to the technical field of rubber materials, and particularly relates to a steel wire cord fabric rubber composition containing a hydrazide compound as well as a preparation method and application of the steel wire cord fabric rubber composition. The steel wire cord fabric rubber composition containing the hydrazide compound comprises the following components in parts by weight: 100 parts of natural rubber, 30-60 parts of carbon black, 1-40 parts of white carbon black, 5-15 parts of zinc oxide, 0-2 parts of cobalt boroacylate, 1-3 parts of resorcinol, 2-10 parts of an adhesive, 3-8 parts of insoluble sulfur, 0.5-3 parts of an accelerant, 0.5-4 parts of an anti-aging agent and 0.5-4 parts of the hydrazide compound. According to the invention, the decline rate of the adhesive property of the rubber is obviously reduced, especially under the conditions of high temperature and long-term use, the problem of aging stability of the interface of the steel wire and the rubber is solved, the influence of metal ions such as Fe < 3 + > and Cu < 2 + > released by the steel wire cord due to long-term heat accumulation of the rubber is reduced, and the rubber composition is especially suitable for all-steel radial truck tires.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber materials, and particularly relates to a steel cord rubber composition containing a hydrazide compound, and a preparation method and application thereof. Background Art

[0002] Load-carrying radial tires are a type of radial tires, mainly used on heavy vehicles and construction machinery. Load-carrying radial tires have a complex structure, with the carcass cords arranged in a radial direction, and the carcass cords are made of high-strength steel wire. Compared with ordinary fiber cords, copper-plated steel cords have higher tensile strength, rigidity, and higher adhesion to rubber, and can withstand greater loads. However, the bonding strength between steel cords and rubber is a key factor affecting tire durability. During long-term use, due to factors such as uneven load distribution, periodic deformation, and heat generation, the bonding performance between steel wire and rubber will gradually decrease, leading to delamination or peeling. In particular, due to the exposed cut surface of the steel wire end without the copper coating, the steel cord releases Fe under high temperature conditions (>80°C). 3+ and Cu 2+ These ions will have a negative impact on tire performance, such as reducing the adhesion between rubber and steel wire and accelerating rubber aging.

[0003] To delay rubber aging and reduce the effects of metal ions on rubber properties, a common technique involves 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. These antioxidants can effectively slow the aging process of rubber, but traditional amine antioxidants (such as 6PPD) tend to migrate to the metal surface, causing them to lose effectiveness over 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 often added to the rubber formulation. However, while these methods can improve initial adhesion to a certain extent, they struggle to significantly reduce the rate of decline in rubber adhesion performance, especially under high temperature and long-term use. Therefore, existing technologies remain deficient in addressing the aging stability issue at the steel cord-rubber interface. Summary of the Invention

[0004] The purpose of the present invention is to provide a steel cord rubber composition containing a hydrazide compound, a preparation method and an application thereof, and to improve the aging stability of the rubber-metal interface by adding the hydrazide compound.

[0005] In order to achieve the above object, the technical solution of the present invention is:

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

[0007] The hydrazide-containing compound is one of oxalyl dihydrazide, 1,2-bis(2-hydroxybenzoyl)hydrazide, 1-naphthoylhydrazide and a compound having a structure of general formula I;

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

[0009]

[0010] Wherein, R is selected from one or more of C1-C10 alkyl, carbonyl, hydroxyl, carboxyl, aldehyde, amino, and naphthyl.

[0011] In some other embodiments, the composition includes the following components, calculated by weight: 100 parts of natural rubber, 40-50 parts of carbon black, 5-15 parts of white carbon black, 5-10 parts of zinc oxide, 0.5-1.5 parts of cobalt boroacylate, 1.5-2 parts of resorcinol, 3-5 parts of adhesive, 4-6 parts of insoluble sulfur, 1-2 parts of accelerator, 1-3 parts of antioxidant, and 0.5-3.5 parts of hydrazide-containing compound;

[0012] The hydrazide compound is one of oxalyl dihydrazide, 1,2-bis(2-hydroxybenzoyl)hydrazide and 1-naphthoyl hydrazide.

[0013] In some other embodiments, the composition includes the following components, calculated by weight: 100 parts of natural rubber, 45 parts of carbon black, 10 parts of white carbon black, 8 parts of zinc oxide, 1 part of cobalt boroacylate, 1.8 parts of resorcinol, 3.5 parts of adhesive, 5 parts of insoluble sulfur, 1.5 parts of accelerator, 2 parts of antioxidant, and 2 parts of hydrazide-containing compound;

[0014] The hydrazide compound is 1-naphthoylhydrazide.

[0015] In some other embodiments, the natural rubber includes natural rubber STR20 and natural rubber SVR3L;

[0016] The carbon black is one or more of carbon black N220, N326, N375 and N330;

[0017] Preferably, the carbon black is carbon black N220;

[0018] The silica content of the white carbon black is ≥92.0wt%, the heating loss at 105°C is 5-6wt%, the ignition loss is ≤6.0wt%, and the specific surface area is 175-195m 2 / g;

[0019] The zinc oxide is an indirect zinc oxide, wherein the zinc oxide content in the indirect zinc oxide is ≥99.50wt% and the specific surface area is 4-6m 2 / g;

[0020] Preferably, the acetone extract of the natural rubber STR20 is 1.5-3.2 wt%;

[0021] The acetone extract of the natural rubber SVR3L is 2.5-4.5 wt%.

[0022] In some other embodiments, the cobalt content in the cobalt boroacylate is 21-23 wt %;

[0023] The content of the resorcinol is ≥99.5wt% and the DSC melting point is 110.0-114.0°C;

[0024] The acetone-insoluble matter in the adhesive RA65 is 30-40 wt%, and the ash content at 850°C is 30-35 wt%;

[0025] 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 of ≤25%, and a DSC melting point of 125-140° C.

[0026] In some other embodiments, the accelerator is accelerator DZ, wherein the oil-free sulfenamide component in the accelerator DZ is ≥ 97 wt % and the cyclohexane insoluble matter is ≤ 0.5 wt %;

[0027] The antioxidant is 6PPD, and the content of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine in the antioxidant 6PPD is ≥96.0 wt%.

[0028] In a second aspect, the present invention provides a method for preparing the steel cord rubber composition containing a hydrazide compound according to the first aspect, comprising the following steps:

[0029] (3) adding natural rubber, carbon black and zinc oxide into an internal mixer and mixing them to form a masterbatch M1;

[0030] (4) adding the first stage masterbatch M1 into an internal mixer and mixing, then adding white carbon black, antioxidant, and cobalt boroacylate, and continuing to mix to prepare the second stage masterbatch M2;

[0031] (3) Add the second-stage masterbatch M2 into an internal mixer and mix, then add resorcinol and continue mixing to prepare the third-stage masterbatch M3;

[0032] (4) The three-stage masterbatch M3, adhesive, insoluble sulfur, and accelerator are added to an internal mixer and mixed, and then the hydrazide compound is added and mixed to form the final rubber.

[0033] In some other embodiments, in step (1), the speed of the internal mixer is 42-46 rpm, the upper push bolt pressure is 0.50-0.60 MPa, the water temperature in the mixing chamber is 30-40° C., the mixing time is 35-45 s, and the binder removal temperature is 150-165° C.;

[0034] In step (2), the speed of the internal mixer is 30-35 rpm, the upper bolt pressure is 0.50-0.60 MPa, and the water temperature in the mixing chamber is 30-40°C; the mixing time of the masterbatch M1 is 15-25 seconds, the continued mixing time is 35-45 seconds, and the discharge temperature is 150-160°C;

[0035] In step (3), the speed of the internal mixer is 30-35 rpm, the upper bolt pressure is 0.50-0.60 MPa, and the water temperature in the mixing chamber is 30-40°C; the mixing time of the second-stage masterbatch M2 is 15-25 seconds, the continued mixing time is 35-45 seconds, and the discharge temperature is 140-145°C;

[0036] In step (4), the speed of the internal mixer is 15-25 rpm, the upper bolt pressure is 0.45-0.50 MPa, the water temperature in the mixing chamber is 25-35° C., the mixing time is 25-30 s, the mixing time is continued for ≥30 s, and the binder removal temperature is 100-110° C.

[0037] In some other embodiments, in step (1), step (2) and step (3), after mixing, the rubber material in the internal mixer is discharged into a twin-screw extruder for tableting, cooling and storing for standby use;

[0038] The distance between the two rollers of the twin-screw extruder is set to 5-10 cm, the roller temperature is 85-105°C, and the screw temperature is 75-95°C;

[0039] The cooling period is 7-9 hours.

[0040] A method for preparing a steel cord rubber composition containing a hydrazide compound comprises the following steps:

[0041] (1) Primary masterbatch M1: A primary masterbatch was prepared using a GK420 internal mixer; natural rubber STR20 / SVR3L, N220 carbon black, and zinc oxide were used as primary masterbatch materials; the internal mixer speed was 45 rpm, the top bolt pressure was 0.55 MPa, and the mixing chamber water temperature was controlled at 35 ± 5 °C;

[0042] Add the above materials into the internal mixer, press the upper push pin and hold it for 40 seconds until the pressure reaches the set value;

[0043] Lift the top bolt and hold for 5 seconds;

[0044] Press the top bolt and keep it until the temperature of the rubber compound reaches 150℃, then lift the top bolt upwards;

[0045] Press the top bolt and keep the temperature of the rubber compound at 165℃, then drain the rubber compound in the internal mixer to the twin-screw extruder;

[0046] The twin-screw extruder tablet press cools down a section of masterbatch M1 and leaves it for 8 hours for standby use (parameter setting: the distance between the two rollers is set to 5cm-10cm, the roller temperature is 95±10℃, and the screw temperature is 85±10℃);

[0047] (2) Second stage masterbatch M2: The second stage masterbatch was made using an internal mixer GK420; the first stage masterbatch M1, white carbon black, antioxidant, and cobalt boroacylate were the materials for the second stage masterbatch M2; the internal mixer speed was 35 rpm, the upper bolt pressure was 0.55 MPa, and the water temperature in the mixing chamber was controlled at 35 ± 5 °C;

[0048] Add the masterbatch M1 into the internal mixer, press down the top bolt and wait for the pressure to reach the set value and hold for 20 seconds;

[0049] Lift the top plug and add white carbon black and cobalt boroacylate;

[0050] Press the top bolt and hold for 40 seconds;

[0051] Lift the top bolt and hold for 5 seconds

[0052] Press the top bolt until the material temperature in the internal mixer reaches 155℃, then drain the rubber material in the internal mixer into the twin-screw extruder;

[0053] The twin-screw extruder tablet press cools the second-stage masterbatch M2 and leaves it for 8 hours for standby 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℃);

[0054] (3) Three-stage masterbatch M3: The three-stage masterbatch was made using an internal mixer GK420; the second-stage masterbatch M2 and resorcinol were the materials for the three-stage masterbatch M3; the internal mixer speed was 35 rpm, the upper bolt pressure was 0.55 MPa, and the water temperature in the mixing chamber was controlled at 35 ± 5 °C;

[0055] Add the second stage masterbatch M2 into the internal mixer, press the top bolt and wait for the pressure to reach the set value and hold for 20 seconds;

[0056] Lift the top plug and add resorcinol;

[0057] Press the top bolt and hold for 40 seconds;

[0058] Lift the top bolt and hold for 5 seconds

[0059] Press the top bolt until the material temperature in the internal mixer reaches 145℃, then drain the rubber material in the internal mixer into the twin-screw extruder;

[0060] The twin-screw extruder tablet press cools the second-stage masterbatch M2 and leaves it for 8 hours for standby 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℃);

[0061] (4) Final mixing: The final mixing was carried out using an internal mixer GK255; the materials for the final mixing were three-stage masterbatch M3, adhesive RA65, insoluble sulfur, accelerator, and hydrazide compound; the internal mixer speed was 25 rpm / 15 rpm, the upper bolt pressure was 0.45 MPa, and the water temperature in the mixing chamber was controlled at 30 ± 5 °C;

[0062] Add the three-stage masterbatch M3, adhesive RA65, insoluble sulfur and accelerator into the internal mixer, press the top bolt and hold it for 30 seconds until the pressure reaches the set value;

[0063] Lift the top bolt and hold for 5 seconds;

[0064] Press the top bolt until the temperature reaches 90℃ and adjust the mixer speed to 15rpm;

[0065] Lift the top plug and add the hydrazide compound;

[0066] Press the top bolt until the temperature reaches 105℃ and the last step of bolt pressing time is ≥30 seconds, then discharge the rubber to the open mill for sheeting for the next process of cord and film production.

[0067] In a third aspect, the present invention provides use of the steel cord rubber composition containing a hydrazide compound as described in the first aspect in a load-bearing radial tire.

[0068] Beneficial effects of the present invention:

[0069] The present invention improves the adhesion and antioxidant capacity of rubber and steel wire through three mechanisms: metal chelation, free radical capture and interface cross-linking. 3+ Forming a stable five-membered ring complex effectively inhibits the Fenton reaction, reduces the metal catalytic oxidation rate, and makes Fe 3+The concentration decreases. Furthermore, the naphthalene ring conjugated system efficiently captures hydroxyl radicals, with a capture efficiency 18% higher than 6PPD, and synergizes with 6PPD to form a dual-mechanism antioxidant network. Furthermore, the hydrazine groups react with rubber vulcanization intermediates to form CNS crosslinks, enhancing the heat resistance of the rubber-steel wire interface. DETAILED DESCRIPTION

[0070] Those skilled in the art will appreciate that the following examples are intended to illustrate the present invention only and should not be construed as limiting the scope of the invention. Unless otherwise specified, the examples were performed under conventional conditions or manufacturer's recommended conditions. Components used without manufacturer's indication are commercially available conventional products.

[0071] 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.), antioxidant 6PPD (Shandong Shengao Chemical Co., Ltd.);

[0072] The properties of some of the raw materials used are as follows: natural rubber STR20 acetone extract 1.5-3.2wt%; natural rubber SVR3L acetone extract 2.5-4.5wt%;

[0073] White carbon black silica content ≥92.0wt%, heating loss (105℃) 5-6wt%, ignition loss ≤6.0wt%, specific surface area 180±15m 2 / g;

[0074] Zinc oxide is indirect zinc oxide, with a zinc oxide content of ≥99.50wt% and a specific surface area of ​​5.0±1.0m 2 / g;

[0075] The cobalt content of cobalt boroacylate is 22.5±0.7wt%;

[0076] Resorcinol content ≥99.5wt%, DSC melting point 110.0-114.0℃;

[0077] Adhesive RA65 acetone insoluble matter 34.0±2.5wt%, ash (850℃) 30-35wt%;

[0078] Insoluble sulfur is OT20, oil content 19.5±1.5%, total sulfur content 80.0±1.5wt%, thermal reduction ≤25%, DSC melting point 132.0±6.0℃;

[0079] Accelerator DZ, sulfenamide content (excluding oil) ≥ 97 wt%, cyclohexane insoluble matter ≤ 0.5 wt%;

[0080] Antioxidant 6PPD, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine content ≥96.0wt%.

[0081] In order to solve the problem of reducing the long-term heat accumulation of rubber during the loading process of the all-steel radial tire, which causes the steel cord to release Fe 3+ and Cu 2+ To address the effects of metal ions such as chlorinated ...

[0082] Example 1

[0083] A steel cord rubber composition containing a hydrazide compound comprises the following components in parts by weight (as shown in Table 1):

[0084] 100 parts of natural rubber (100 parts of natural rubber STR20), 45 parts of carbon black (carbon black N220), 10 parts of white carbon black, 8 parts of zinc oxide, 1 part of cobalt boroacylate, 1.8 parts of resorcinol, 3.5 parts of adhesive (adhesive RA65), 5 parts of insoluble sulfur (insoluble sulfur OT20), 1.5 parts of accelerator (accelerator DZ), 2 parts of antioxidant (antioxidant 6PPD), 2 parts of hydrazide-containing compounds (0 parts of oxalyl dihydrazide, 0 parts of 1,2-bis(2-hydroxybenzoyl)hydrazine, 2 parts of 1-naphthoylhydrazide).

[0085] The preparation method of a steel cord rubber composition containing a hydrazide compound comprises the following steps:

[0086] (1) Preparation of primary masterbatch M1

[0087] Natural rubber, carbon black, and zinc oxide were used as raw materials for a masterbatch. A masterbatch was prepared using a GK420 internal mixer at a mixer speed of 45 rpm, a top bolt pressure of 0.55 MPa, and a mixing chamber water temperature of 35±5°C. A masterbatch was added to the internal mixer, and the top bolt was pressed down until the pressure reached the set value and held for 40 seconds; the top bolt was lifted and held for 5 seconds; the top bolt was pressed and held until the compound temperature reached 150°C, and the top bolt was lifted upward; the top bolt was pressed and held until the compound temperature reached 165°C, and the compound in the internal mixer was emptied into a twin-screw extruder; the twin-screw extruder extruder extruded a masterbatch M1 and cooled it for 8 hours for standby use (parameter settings: the distance between the two rollers was set to 5 cm to 10 cm, the roller temperature was set to 95±10°C, and the screw temperature was set to 85±10°C).

[0088] (2) Preparation of second-stage masterbatch M2

[0089] The first-stage masterbatch M1, white carbon black, antioxidant, and cobalt boroacylate were used as raw materials for the second-stage masterbatch M2. The second-stage masterbatch was prepared using a GK420 internal mixer at a mixer speed of 35 rpm, a top plug pressure of 0.55 MPa, and a mixing chamber water temperature of 35±5°C. The first-stage masterbatch M1 was added to the internal mixer, and the top plug was pressed down until the pressure reached the set value and held for 20 seconds; the top plug was lifted, and white carbon black and cobalt boroacylate were added; the top plug was pressed and held for 40 seconds; the top plug was lifted and held for 5 seconds; the top plug was pressed again until the material temperature in the internal mixer reached 155°C, and the rubber material in the internal mixer was emptied into a twin-screw extruder; the twin-screw extruder extruded the second-stage masterbatch M2 and cooled it for 8 hours for standby use (parameter settings: the distance between the two rollers was set to 5 cm to 10 cm, the roller temperature was set to 95±10°C, and the screw temperature was set to 85±10°C).

[0090] (3) Preparation of three-stage masterbatch M3

[0091] 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 an internal mixer GK420. The mixer speed was 35 rpm, the upper bolt pressure was 0.55 MPa, and the water temperature in the mixing chamber was controlled at 35±5°C.

[0092] Add the second-stage masterbatch M2 into the internal mixer, press down the top bolt and hold it until the pressure reaches the set value for 20 seconds; lift the top bolt and add resorcinol; press the top bolt and hold it for 40 seconds; lift the top bolt and hold it for 5 seconds; press the top bolt until the material temperature in the internal mixer reaches 145°C, then empty the rubber material in the internal mixer into the twin-screw extruder; the twin-screw extruder tablet press will tablet the second-stage masterbatch M2 and cool it for 8 hours for standby use (parameter setting: the distance between the two rollers is set to 5cm~10cm, the roller temperature is 95±10°C, and the screw temperature is 85±10°C).

[0093] (4) Preparation of final rubber

[0094] The final mix was prepared using a GK255 internal mixer, consisting of three-stage masterbatch M3, adhesive RA65, insoluble sulfur, accelerator, and hydrazide compound. The mixer speed was 25 rpm / 15 rpm, the top bolt pressure was 0.45 MPa, and the mixing chamber temperature was controlled at 30±5°C. The three-stage masterbatch M3, adhesive RA65, insoluble sulfur, and accelerator were added to the internal mixer. The top bolt was pressed down until the pressure reached the set value and held for 30 seconds. The top bolt was then raised and held for 5 seconds. The top bolt was then pressed until the temperature reached 90°C. The internal mixer speed was then adjusted to 15 rpm. The top bolt was then raised, the hydrazide compound was added, and the top bolt was pressed down until the temperature reached 105°C. The final pressing time was ≥30 seconds. The rubber was then discharged to the open mixer for sheeting, which was then used for the next step of cord and film production.

[0095] Example 2

[0096] A steel cord rubber composition containing a hydrazide compound, the components of which are shown in Table 1 in parts by weight. The difference from Example 1 is that the natural rubber is 100 parts of natural rubber SVR3L; the other components and preparation method are consistent with Example 1.

[0097] Example 3

[0098] A steel cord rubber composition containing a hydrazide compound, the components of which are shown in Table 1 in parts by weight. Unlike Example 1, the natural rubber comprises 50 parts of natural rubber STR20 and 50 parts of natural rubber SVR3L, and contains 2 parts of a hydrazide compound (2 parts of oxalyl dihydrazide). Other components and preparation methods are consistent with those of Example 1.

[0099] Example 4

[0100] A steel cord rubber composition containing a hydrazide compound, the components of which are shown in Table 1 in parts by weight. The difference from Example 3 is that the composition contains 2 parts of a hydrazide compound (2 parts of 1,2-bis(2-hydroxybenzoyl)hydrazine); the other components and preparation method are consistent with Example 3.

[0101] Example 5

[0102] A steel cord rubber composition containing a hydrazide compound, the components of which are shown in Table 1 in parts by weight. The difference from Example 3 is that the composition contains 0.5 parts of a hydrazide compound (0.5 parts of 1-naphthoic acid hydrazide); the other compositions and preparation methods are consistent with those of Example 3.

[0103] Example 6

[0104] A steel cord rubber composition containing a hydrazide compound, the components of which are shown in Table 1 in parts by weight. The difference from Example 3 is that it contains 2 parts of a hydrazide compound (2 parts of 1-naphthoylhydrazide); the other compositions and preparation methods are consistent with those of Example 3.

[0105] Example 7

[0106] A steel cord rubber composition containing a hydrazide compound, the components of which are shown in Table 1 in parts by weight. The difference from Example 3 is that it contains 3.2 parts of a hydrazide compound (3.2 parts of 1-naphthoic acid hydrazide); the other compositions and preparation methods are consistent with those of Example 3.

[0107] Comparative Example 1

[0108] A steel cord rubber composition, the components of which are shown in Table 1 in parts by weight; different from Example 1, the natural rubber consists of 50 parts of natural rubber STR20 and 50 parts of natural rubber SVR3L, and no hydrazide-containing compound is added; the other compositions are consistent with Example 1.

[0109] In the preparation method, in step (4) of preparing the final rubber mix, three-stage masterbatch M3, adhesive RA65, insoluble sulfur, and accelerator are used as raw materials for the final rubber mix, and a GK255 internal mixer is used to prepare the final rubber mix. The internal mixer speed is 25rpm / 15rpm, the upper push pin pressure is 0.45Mpa, and the water temperature in the mixing chamber is controlled at 30±5°C. The three-stage masterbatch M3, adhesive RA65, insoluble sulfur, and accelerator are added to the internal mixer, and the upper push pin is pressed down and held until the pressure reaches the set value for 30 seconds; the upper push pin is lifted and held for 5 seconds; the push pin is pressed until the temperature reaches 90°C, and the internal mixer speed is adjusted to 15rpm; the push pin is lifted; the push pin is pressed until the temperature reaches 105°C and the last push pin pressing time is ≥30 seconds. The rubber is discharged to the open mixer for sheeting for the next process of cord and film production.

[0110] Table 1 Composition of the steel cord rubber composition in the examples and comparative examples

[0111]

[0112]

[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 Truck Tire Performance Indoor Test Method.

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

[0117] The performance data for Comparative Example 1 and Examples 1-7 are expressed as indices, with the values ​​for modulus, tensile strength, elongation at break, adhesion, adhesion after heat aging, and durability of the finished tire for Comparative Example 1 set at 100. For Examples 1-7, higher values ​​indicate better performance compared to 100. The specific test results are shown in Table 2.

[0118] Table 2 Properties of the steel cord rubber compositions in Examples and Comparative Examples

[0119]

[0120] From the results in Table 2, it can be seen that, compared with Comparative Example 1, the rubber compositions of each embodiment have better steel wire adhesion after aging at 100°C*72h under the condition of comparable tensile strength, elongation at break, and modulus of tensile stress, and the finished tires have better durability.

[0121] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A steel cord rubber composition containing a hydrazide compound, characterized in that: The composition comprises the following components in parts by weight: 100 parts of natural rubber, 30-60 parts of carbon black, 1-40 parts of white carbon black, 5-15 parts of zinc oxide, 0-2 parts of cobalt boroacylate, 1-3 parts of resorcinol, 2-10 parts of adhesive, 3-8 parts of insoluble sulfur, 0.5-3 parts of accelerator, 0.5-4 parts of antioxidant, and 0.5-4 parts of hydrazide compound; The hydrazide-containing compound is one of oxalyl dihydrazide, 1,2-bis(2-hydroxybenzoyl)hydrazide, 1-naphthoylhydrazide and a compound having a structure of general formula I; The structure of the compound having the general formula I is shown below: Wherein, R is selected from one or more of C1-C10 alkyl, carbonyl, hydroxyl, carboxyl, aldehyde, amino, and naphthyl.

2. The steel cord rubber composition containing a hydrazide compound according to claim 1, wherein The composition comprises the following components in parts by weight: 100 parts of natural rubber, 40-50 parts of carbon black, 5-15 parts of white carbon black, 5-10 parts of zinc oxide, 0.5-1.5 parts of cobalt boroacylate, 1.5-2 parts of resorcinol, 3-5 parts of adhesive, 4-6 parts of insoluble sulfur, 1-2 parts of accelerator, 1-3 parts of antioxidant, and 0.5-3.5 parts of hydrazide compound; The hydrazide compound is one of oxalyl dihydrazide, 1,2-bis(2-hydroxybenzoyl)hydrazide and 1-naphthoyl hydrazide.

3. The steel cord rubber composition containing a hydrazide compound according to claim 1, wherein The composition is as follows, calculated by weight: 100 parts of natural rubber, 45 parts of carbon black, 10 parts of white carbon black, 8 parts of zinc oxide, 1 part of cobalt boroacylate, 1.8 parts of resorcinol, 3.5 parts of adhesive, 5 parts of insoluble sulfur, 1.5 parts of accelerator, 2 parts of antioxidant, and 2 parts of hydrazide-containing compound; The hydrazide compound is 1-naphthoylhydrazide.

4. The steel cord rubber composition containing a hydrazide compound according to 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 content of the white carbon black is ≥92.0wt%, the heating loss at 105°C is 5-6wt%, the ignition loss is ≤6.0wt%, and the specific surface area is 175-195m 2 / g; The zinc oxide is an indirect zinc oxide, wherein the zinc oxide content in the indirect zinc oxide is ≥99.50wt% and the specific surface area is 4-6m 2 / g; Preferably, the acetone extract of the natural rubber STR20 is 1.5-3.2 wt%; The acetone extract of the natural rubber SVR3L is 2.5-4.5 wt%.

5. The steel cord rubber composition containing a hydrazide compound according to claim 1, wherein The cobalt content in the cobalt boroacylate is 21-23 wt%; The content of the resorcinol is ≥99.5wt% and the DSC melting point is 110.0-114.0°C; The acetone-insoluble matter in the adhesive RA65 is 30-40 wt%, and the ash content at 850°C 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 of ≤25%, and a DSC melting point of 125-140° C.

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

7. A method for preparing a steel cord rubber composition containing a hydrazide compound according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Natural rubber, carbon black and zinc oxide are added into an internal mixer and mixed to form a masterbatch M1; (2) adding the first-stage masterbatch M1 into an internal mixer and mixing, then adding white carbon black, antioxidant, and cobalt boroacylate, and continuing to mix to prepare the second-stage masterbatch M2; (3) Add the second-stage masterbatch M2 into an internal mixer and mix, then add resorcinol and continue mixing to prepare the third-stage masterbatch M3; (4) The three-stage masterbatch M3, adhesive, insoluble sulfur, and accelerator are added to an internal mixer and mixed, and then the hydrazide compound is added and mixed to form the final rubber.

8. The method for preparing a steel cord rubber composition containing a hydrazide compound according to claim 7, wherein: In step (1), the speed of the internal mixer is 42-46 rpm, the upper bolt pressure is 0.50-0.60 MPa, the water temperature in the mixing chamber is 30-40° C., the mixing time is 35-45 s, and the binder removal temperature is 150-165° C.; In step (2), the speed of the internal mixer is 30-35 rpm, the upper bolt pressure is 0.50-0.60 MPa, and the water temperature in the mixing chamber is 30-40°C; the mixing time of the masterbatch M1 is 15-25 seconds, the continued mixing time is 35-45 seconds, and the discharge temperature is 150-160°C; In step (3), the speed of the internal mixer is 30-35 rpm, the upper bolt pressure is 0.50-0.60 MPa, and the water temperature in the mixing chamber is 30-40°C; the mixing time of the second-stage masterbatch M2 is 15-25 seconds, the continued mixing time is 35-45 seconds, and the discharge temperature is 140-145°C; In step (4), the speed of the internal mixer is 15-25 rpm, the upper bolt pressure is 0.45-0.50 MPa, the water temperature in the mixing chamber is 25-35° C., the mixing time is 25-30 s, the mixing time is continued for ≥30 s, and the binder removal temperature is 100-110° C.

9. The method for preparing a steel cord rubber composition containing a hydrazide compound according to claim 7, wherein: In step (1), step (2) and step (3), after mixing, the rubber material in the internal mixer is discharged into a twin-screw extruder for tableting, cooling and storing for standby use; The distance between the two rollers of the twin-screw extruder is set to 5-10 cm, the roller temperature is 85-105°C, and the screw temperature is 75-95°C; The cooling period is 7-9 hours.

10. Use of the steel cord rubber composition containing a hydrazide compound according to any one of claims 1 to 6 in a load-bearing radial tire.

Images