1. A nitrile rubber-based vulcanization composition, characterized in that the composition contains the following components stored in admixture or separately:

the rubber composition comprises a rubber matrix, a reinforcing agent, calcium sulfate whiskers, a vulcanizing agent, a vulcanization accelerator, a vulcanization activator, and optionally an anti-aging agent and/or a plasticizer, wherein the rubber matrix is nitrile rubber, and the reinforcing agent is a combination of carbon black and white carbon black;

the vulcanization accelerator is at least one selected from thiuram accelerators, dithiocarbamate accelerators and sulfenamide accelerators;

relative to 100 parts by weight of the rubber matrix, the content of the carbon black is 50-120 parts by weight, and the content of the white carbon black is 10-30 parts by weight; the calcium sulfate whisker is 5-40 parts by weight, the vulcanizing agent is 0.2-1.5 parts by weight, the vulcanization accelerator is 1-6 parts by weight, the vulcanization activator is 1-20 parts by weight, the anti-aging agent is 0-10 parts by weight, and the plasticizer is 0-40 parts by weight.

2. The composition according to claim 1, wherein the carbon black is contained in an amount of 70 to 90 parts by weight and the white carbon black is contained in an amount of 15 to 30 parts by weight, relative to 100 parts by weight of the rubber matrix;

preferably, the carbon black has a specific surface area of 25m²/g-130m²/g；

Preferably, the specific surface area of the white carbon black is 70m²/g-250m²/g。

3. The composition according to claim 1 or 2, wherein the calcium sulfate whiskers are present in an amount of 5 to 30 parts by weight, preferably 10 to 20 parts by weight, relative to 100 parts by weight of the rubber matrix;

preferably, the aspect ratio of the calcium sulfate whiskers is 15-200, more preferably 30-80, and the average diameter is 1-6 μm.

4. The composition according to any one of claims 1 to 3, wherein the nitrile rubber has a bound acrylonitrile structural unit content of 10 to 50% by weight and a Mooney viscosity ML (1+4) at 100 ℃ of 30 to 100 in the rubber matrix.

5. The composition according to any one of claims 1 to 4, wherein the carbon black is contained in an amount of 70 to 90 parts by weight and the white carbon black is contained in an amount of 15 to 30 parts by weight, relative to 100 parts by weight of the rubber matrix; the calcium sulfate whisker is 10-20 parts by weight, the vulcanizing agent is 0.3-1 part by weight, the vulcanization accelerator is 1-6 parts by weight, the vulcanization activator is 4-10 parts by weight, the anti-aging agent is 2-8 parts by weight, and the plasticizer is 5-20 parts by weight.

6. The composition according to any one of claims 1 to 5, wherein the vulcanization accelerator is a thiuram-type accelerator or a dithiocarbamate-type accelerator, and is contained in an amount of 1 to 3 parts by weight per 100 parts by weight of the rubber matrix;

preferably, the vulcanization accelerator is a combination of a sulfenamide accelerator and a thiuram accelerator or a dithiocarbamate accelerator, and the content of the sulfenamide accelerator is 0.1 to 3 parts by weight and the content of the thiuram accelerator or the dithiocarbamate accelerator is 1 to 3 parts by weight, relative to 100 parts by weight of the rubber base;

preferably, the vulcanization accelerator is a combination of N-cyclohexyl-2-benzothiazolesulfenamide and tetramethylthiuram disulfide or zinc dimethyldithiocarbamate.

7. The composition according to any one of claims 1-6, wherein the vulcanizing agent is selected from at least one of sulfur donors, preferably the vulcanizing agent is sulfur;

preferably, the vulcanization activator is a mixture of a metal oxide and a fatty acid, preferably the vulcanization activator is a combination of zinc oxide and stearic acid, preferably the zinc oxide is present in an amount of 3 to 7 parts by weight and the stearic acid is present in an amount of 1 to 3 parts by weight, relative to 100 parts by weight of the rubber matrix;

preferably, the anti-aging agent is selected from at least one of quinoline anti-aging agents, p-phenylenediamine anti-aging agents, naphthylamine anti-aging agents and imidazole anti-aging agents; preferably, the quinoline antioxidant is at least one of 2,2, 4-trimethyl-1, 2-dihydroquinoline polymer, 6-ethoxy-2, 2, 4-trimethyl-1, 2-dihydroquinoline and 6-dodecyl-2, 2, 4-trimethyl-1, 2-dihydroquinoline, the p-phenylenediamine antioxidant is at least one of 4,4' -dioctyl diphenylamine, N-isopropylphenyl-N ' -phenyl-p-phenylenediamine and N, N ' -diphenyl-p-phenylenediamine, the naphthylamine antioxidant is N-phenyl-2-naphthylamine, and the imidazole antioxidant is 2-mercaptobenzimidazole;

preferably, the plasticizer is selected from at least one of a coal tar-based plasticizer, a fatty oil-based plasticizer, and a synthetic plasticizer; preferably, the plasticizer is at least one of coumarone resin, phthalate, phosphate and fatty dibasic acid ester.

8. A method of preparing a vulcanizate, the method comprising: mixing the components of the composition of any one of claims 1-7 to form a mix, and subjecting the mix to a vulcanization treatment;

preferably, the operation of mixing the components comprises the following steps:

(1) carrying out first mixing on a component A containing a rubber matrix, a reinforcing agent, calcium sulfate whiskers, a vulcanization activator and optionally an anti-aging agent and/or a plasticizer to prepare a master batch;

(2) and carrying out second mixing on the master batch and a component B containing a vulcanizing agent and a vulcanization accelerator to obtain the rubber compound.

9. The method of claim 8, wherein the conditions of the first mixing comprise: the temperature is 60-80 deg.C, and the time is 3-5 min;

preferably, the first mixing is carried out in an internal mixer at a speed of 50 to 90rpm, more preferably 60 to 80 rpm;

preferably, the conditions of the second mixing include: the temperature is 40-60 deg.C, and the time is 3-4 min;

preferably, the second mixing is carried out in an internal mixer at a speed of 40 to 80rpm, more preferably 50 to 70 rpm.

10. The method according to claim 8 or 9, wherein the conditions of the vulcanization process include: the vulcanization temperature is 160-200 ℃, and preferably 170-190 ℃;

the vulcanization pressure is 3-20MPa, preferably 10-15 MPa;

the vulcanization time is from 30 to 600s, preferably from 60 to 300 s.

11. A vulcanized rubber produced by the method of any one of claims 8 to 10.

12. Use of the vulcanizate of claim 11 in a sealing material.

Background

The nitrile rubber is a random copolymer synthesized by a method of emulsion free radical polymerization of butadiene and acrylonitrile. Due to the introduction of a strongly polar acrylonitrile structural unit in a rubber molecular chain, the nitrile rubber has many different performance characteristics from other general rubbers, such as oil resistance, heat resistance, wear resistance, solvent resistance and the like. These unique properties make nitrile rubbers widely used in various fields of production and life, wherein rubber sealing materials (such as oil seals, O-rings, etc.) are an important application field of nitrile rubbers.

Currently, because of the requirement of production efficiency, rubber sealing materials are usually produced by a high-temperature rapid vulcanization process, so that vulcanized rubber for preparing the rubber sealing materials is required to have excellent mechanical properties, compression permanent deformation resistance and other properties, and simultaneously, rubber compound is required to have good processability, for example, appropriate mooney viscosity of the rubber compound (endowing the rubber compound with excellent fluidity on the premise of ensuring the use properties of the products), a compounding system suitable for high-temperature rapid vulcanization and other traditional methods for improving the processability of rubber compounds, such as increasing the use amount of a plasticizer, selecting and using large-particle-size carbon black, using crude rubber with lower mooney viscosity and the like can obviously reduce the physical properties of the vulcanized rubber, thereby affecting the application properties of the sealing materials. If the raw rubber with higher Mooney viscosity is selected, the physical properties of the sealing material can be improved by using the carbon black with better reinforcing property or reducing the dosage of the plasticizer, but the difficulty of processing products is increased due to poor fluidity of the rubber compound, and the defect rate in the production process of the products is possibly increased.

In the field of rubber sealing materials, particularly rubber sealing materials using nitrile rubber as a matrix, many publications and patent documents have been reported.

CN106543505A discloses a high-performance nitrile rubber sealing material and a preparation method thereof, wherein the high-performance nitrile rubber sealing material comprises the following raw materials in parts by weight: 25-35 parts of nitrile rubber, 4-7 parts of a composite vulcanizing agent, 4-5 parts of an anti-aging agent, 8-15 parts of an activating agent, 25-30 parts of a reinforcing agent and 2-5 parts of a heat-resistant auxiliary agent.

CN108102169A discloses a high-hardness nitrile rubber and a preparation method thereof. In order to solve the problem that the existing nitrile rubber sealing material cannot simultaneously give consideration to high hardness and wear resistance, the high-hardness nitrile rubber and the preparation method thereof are provided. The adhesive is prepared from nitrile rubber, zinc oxide, stearic acid, an anti-aging agent, octyl phenolic tackifying resin, carbon black, a softener, a vulcanizing agent and an accelerator according to a certain proportion.

The rubber technology (2018,16 (8): 33-35) introduces the research on the nitrile rubber sealing material with high elasticity and low compression set. The article investigated the effect of acrylonitrile content and cure system on the performance of Nitrile Butadiene Rubber (NBR) seals. The results show that: the NBR has low acrylonitrile content, the vulcanized rubber has high elasticity and small compression permanent deformation, but the tearing strength is lower; the consumption of the accelerator is increased, the elasticity of the vulcanized rubber is improved, the compression permanent deformation is reduced, the consumption of the sulfur is increased, and the compression permanent deformation of the vulcanized rubber is increased; the NBR acrylonitrile mass fraction is about 0.225%, and the vulcanized rubber with low sulfur and high promotion has high elasticity, small compression permanent deformation and good tear resistance.

The prior art researches and researches on certain properties of the sealing material, but does not mention the matching problem of the processing technology of the rubber sealing material and the properties of products.

Disclosure of Invention

The object of the present invention is to provide a rubber composition having good processability, a moderate Mooney viscosity of the rubber compound, and suitable for application to an efficient high-temperature rapid vulcanization production process, in order to obtain a vulcanized rubber having excellent mechanical properties and compression set resistance suitable for use as, for example, a sealing material. That is, the present invention aims to provide a rubber composition suitable for use in an efficient high-temperature rapid vulcanization production process while taking into account processability, mechanical properties and compression set properties of a rubber composite material.

In order to achieve the above object, a first aspect of the present invention provides a nitrile rubber-based vulcanized composition comprising the following components stored in admixture or separately:

the rubber composition comprises a rubber matrix, a reinforcing agent, calcium sulfate whiskers, a vulcanizing agent, a vulcanization accelerator, a vulcanization activator, and optionally an anti-aging agent and/or a plasticizer, wherein the rubber matrix is nitrile rubber, and the reinforcing agent is a combination of carbon black and white carbon black;

the vulcanization accelerator is at least one selected from thiuram accelerators, dithiocarbamate accelerators and sulfenamide accelerators;

relative to 100 parts by weight of the rubber matrix, the content of the carbon black is 50-120 parts by weight, and the content of the white carbon black is 10-30 parts by weight; the calcium sulfate whisker is 5-40 parts by weight, the vulcanizing agent is 0.2-1.5 parts by weight, the vulcanization accelerator is 1-6 parts by weight, the vulcanization activator is 1-20 parts by weight, the anti-aging agent is 0-10 parts by weight, and the plasticizer is 0-40 parts by weight.

A second aspect of the present invention provides a method for preparing a vulcanized rubber, the method comprising: the components of the composition of the invention are mixed to form a rubber compound, and then the rubber compound is vulcanized.

A third aspect of the present invention provides a vulcanizate prepared by the foregoing method.

A fourth aspect of the invention provides the use of the aforementioned vulcanized rubber in a sealing material.

According to the technical scheme, the nitrile rubber is adopted as the rubber matrix, the specific amount of carbon black and white carbon black are adopted as the reinforcing agent, the inorganic filler calcium sulfate whisker with the specific weight is filled, the vulcanizing agent with the specific weight is matched and applied, the vulcanizing agent with the specific type and the vulcanizing accelerator with the specific weight are matched and applied, the prepared rubber composition rubber compound has good processing performance and moderate Mooney viscosity of the rubber compound, and is suitable for being applied to the production process of high-temperature rapid vulcanization, and the prepared vulcanized rubber has excellent mechanical property and compression permanent deformation resistance.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

As previously mentioned, a first aspect of the present invention provides a nitrile rubber-based vulcanizate, wherein the composition comprises the following components stored in admixture or separately:

the rubber composition comprises a rubber matrix, a reinforcing agent, calcium sulfate whiskers, a vulcanizing agent, a vulcanization accelerator, a vulcanization activator, and optionally an anti-aging agent and/or a plasticizer, wherein the rubber matrix is nitrile rubber, and the reinforcing agent is a combination of carbon black and white carbon black;

the vulcanization accelerator is at least one selected from thiuram accelerators, dithiocarbamate accelerators and sulfenamide accelerators;

relative to 100 parts by weight of the rubber matrix, the content of the carbon black is 50-120 parts by weight, and the content of the white carbon black is 10-30 parts by weight; the calcium sulfate whisker is 5-40 parts by weight, the vulcanizing agent is 0.2-1.5 parts by weight, the vulcanization accelerator is 1-6 parts by weight, the vulcanization activator is 1-20 parts by weight, the anti-aging agent is 0-10 parts by weight, and the plasticizer is 0-40 parts by weight.

In order to provide better processability to the rubber compound prepared from the composition of the present invention and provide more excellent mechanical properties and compression set resistance to the vulcanized rubber obtained therefrom, it is more preferable that the carbon black is contained in an amount of 70 to 90 parts by weight and the white carbon black is contained in an amount of 15 to 30 parts by weight with respect to 100 parts by weight of the rubber matrix.

Preferably, the carbon black has a specific surface area of 25m²/g-130m²/g。

Preferably, the specific surface area of the white carbon black is 70m²/g-250m²/g。

In a case where no particular description is given, the specific surface areas of the carbon black and the white carbon black of the present invention are obtained by a CTAB method test.

Preferably, the content of the calcium sulfate whiskers is 5 to 30 parts by weight, preferably 10 to 20 parts by weight, relative to 100 parts by weight of the rubber matrix.

Preferably, the aspect ratio of the calcium sulfate whisker is 15-200, more preferably 30-80, and the average diameter is 1-6 μm.

Preferably, in the rubber matrix, the bound acrylonitrile structural unit content in the nitrile rubber is from 10 to 50% by weight and the Mooney viscosity ML (1+4) at 100 ℃ is from 30 to 100.

Preferably, the carbon black is contained in an amount of 70 to 90 parts by weight and the white carbon black is contained in an amount of 15 to 30 parts by weight, relative to 100 parts by weight of the rubber matrix; the calcium sulfate whisker is 10-20 parts by weight, the vulcanizing agent is 0.3-1 part by weight, the vulcanization accelerator is 1-6 parts by weight, the vulcanization activator is 4-10 parts by weight, the anti-aging agent is 2-8 parts by weight, and the plasticizer is 5-20 parts by weight.

According to a preferred embodiment, the vulcanization accelerator is a thiuram-type accelerator or a dithiocarbamate-type accelerator. In this preferable case, the content of the vulcanization accelerator is 1 to 3 parts by weight with respect to 100 parts by weight of the rubber matrix.

According to another preferred embodiment, the vulcanization accelerator is a combination of a sulfenamide type accelerator and a thiuram type accelerator or a dithiocarbamate type accelerator. In this preferable aspect, the content of the sulfenamide-based accelerator is 0.1 to 3 parts by weight and the content of the thiuram-based accelerator or the dithiocarbamate-based accelerator is 1 to 3 parts by weight based on 100 parts by weight of the rubber base.

Preferably, the vulcanization accelerator is a combination of N-cyclohexyl-2-benzothiazolesulfenamide (accelerator CZ) with tetramethylthiuram disulfide (accelerator TMTD) or zinc dimethyldithiocarbamate (accelerator ZDMC).

Preferably, the vulcanizing agent is selected from at least one of sulfur donors, preferably the vulcanizing agent is sulfur.

Preferably, the curing activator is a mixture of a metal oxide and a fatty acid, preferably the curing activator is a mixture of a metal oxide and a fatty acid, more preferably the curing activator is a combination of zinc oxide and stearic acid.

Preferably, the zinc oxide is contained in an amount of 3 to 7 parts by weight and the stearic acid is contained in an amount of 1 to 3 parts by weight, relative to 100 parts by weight of the rubber matrix.

Preferably, the antioxidant is at least one selected from quinoline antioxidants, p-phenylenediamine antioxidants, naphthylamine antioxidants and imidazole antioxidants.

Preferably, the quinoline antioxidant is at least one of 2,2, 4-trimethyl-1, 2-dihydroquinoline polymer (antioxidant RD), 6-ethoxy-2, 2, 4-trimethyl-1, 2-dihydroquinoline and 6-dodecyl-2, 2, 4-trimethyl-1, 2-dihydroquinoline.

Preferably, the p-phenylenediamine antioxidant is at least one of 4,4' -dioctyl diphenylamine, N-cumyl-N ' -phenyl-p-phenylenediamine (antioxidant 4010NA) and N, N ' -diphenyl-p-phenylenediamine.

Preferably, the naphthylamine antioxidant is N-phenyl-2-naphthylamine (antioxidant D).

Preferably, the imidazole antioxidant is 2-mercaptobenzimidazole (antioxidant MB).

Preferably, the plasticizer is selected from at least one of a coal tar-based plasticizer, a fatty oil-based plasticizer, and a synthetic plasticizer.

Preferably, the plasticizer is at least one of coumarone resin, phthalate (e.g., plasticizer DOP), phosphate (e.g., plasticizer TCP), and fatty dibasic acid ester (e.g., plasticizer DOS).

As previously mentioned, a second aspect of the present invention provides a process for preparing a vulcanized rubber, the process comprising: the components in the composition are mixed to form a mixed rubber, and then the mixed rubber is vulcanized.

The raw materials for preparing the vulcanized rubber in the second aspect of the present invention form the composition described in the aforementioned first aspect of the present invention, and therefore, the kinds of the raw materials in the second aspect of the present invention are all the same as those described in the first aspect of the present invention, and in order to avoid repetition, the present invention is not described in detail in the second aspect, and those skilled in the art should not be construed as limiting the present invention.

In order to obtain better processability of the compound prepared from the composition of the invention and better mechanical properties and compression set resistance of the vulcanizate thus obtained, according to a preferred embodiment, the mixing of the components comprises the following steps:

(1) carrying out first mixing on a component A containing a rubber matrix, a reinforcing agent, calcium sulfate whiskers, a vulcanization activator and optionally an anti-aging agent and/or a plasticizer to prepare a master batch;

(2) and carrying out second mixing on the master batch and a component B containing a vulcanizing agent and a vulcanization accelerator to obtain the rubber compound.

Preferably, the conditions of the first mixing include: the temperature is 60-80 deg.C, and the time is 3-5 min.

Preferably, the conditions of the second mixing include: the temperature is 40-60 deg.C, and the time is 3-4 min.

In the present invention, the first mixing and the second mixing may be carried out in a mixing apparatus, and for example, may be carried out in an open mill or an internal mixer, and preferably, both the first mixing and the second mixing are carried out in an internal mixer.

According to a preferred embodiment, said first mixing is carried out in an internal mixer at a speed of 50 to 90rpm, more preferably 60 to 80 rpm. Preferably, the second mixing is carried out in an internal mixer at a speed of 40 to 80rpm, more preferably 50 to 70 rpm.

Preferably, the conditions of the vulcanization treatment include: the vulcanization temperature is 160-200 ℃, and more preferably 170-190 ℃; the vulcanization pressure is 3-20MPa, more preferably 10-15 MPa; the vulcanization time is from 30 to 600s, more preferably from 60 to 300 s. The vulcanization is preferably carried out in a press vulcanizer.

In the present invention, the discharged rubber may be tabletted, for example, in an open mill, before it is vulcanized. Preferably, the open mill conditions include: the open milling temperature is 50-70 ℃. And the discharged glue after tabletting can be placed for 4 to 48 hours, for example.

Unless otherwise specified, all pressures described herein are expressed as gauge pressure.

As previously mentioned, a third aspect of the present invention provides a vulcanizate prepared by the foregoing method.

As previously mentioned, a fourth aspect of the present invention provides the use of the aforementioned vulcanized rubber in a sealing material.

Compared with the prior art, the invention also has the following specific advantages:

1) the invention uses the reinforcing agent with high filling part, not only reduces the cost of the product, but also reduces the Mooney viscosity of the rubber compound, prevents the disqualification of the product caused by poor fluidity of the rubber compound in the processing process, and simultaneously, the vulcanized rubber has excellent mechanical property and compression permanent deformation resistance.

2) The invention adopts two-stage mixing, namely the first mixing and the second mixing, so that the obtained rubber compound has no scorching phenomenon, the later-stage processing and forming are facilitated, and the product obtained after the subsequent vulcanization has better service performance.

The present invention will be described in detail below by way of examples. In the following examples, various raw materials used were commercially available unless otherwise specified.

Rubber matrix-nitrile rubber: manufactured by Russian-West Boolean company under the designation 1835, the content of acrylonitrile structural units is 18% by weight, the Mooney viscosity ML (1+4) is 30 at 100 ℃;

rubber matrix-nitrile rubber: produced by Russian-West Boolean, Inc. under the designation 4095, the acrylonitrile structural unit content is 45% by weight, the Mooney viscosity ML (1+4) is 100 ℃ at 100 ℃;

rubber matrix-nitrile rubber: produced by Russian-West Boolean, Inc., No. 3365, the content of acrylonitrile structural units is 33% by weight, the Mooney viscosity ML (1+4) is 65 at 100 ℃;

calcium sulfate whisker: the particle size is 1-6um, the length-diameter ratio is 30/1-80/1, and the particle size is produced by Jiangsu Xinyuan mining mailbox company;

carbon black: number N330 (specific surface area 73 m)²/g-85m²Per g) and N550 (specific surface area 36 m)²/g-48m²(g) from Zideli chemical technology, Inc. of Dongguan city;

white carbon black: number 165MP (specific surface area of 150 and 180 m)²(g) from underwriters laboratories, Inc.;

vulcanizing agent: sulfur is purchased from Hechiojiu chemical industry Co., Ltd in the Weifang;

vulcanization accelerator (b): promoter TMTD, promoter CZ, promoter ZDMC, purchased from Shanghai Yongyan chemical technology Co., Ltd;

vulcanization activating agent: zinc oxide and stearic acid purchased from Weifang Heng Feng chemical company Limited;

an anti-aging agent: antioxidant RD, antioxidant 4010NA, antioxidant D, and antioxidant MB, which are purchased from Jiangsu Shengao chemical technology Co., Ltd;

plasticizer: coumarone resin, plasticizer DOP, plasticizer DOS and plasticizer TCP are purchased from Jinan Henry chemical Co., Ltd.

The rubber processing and testing equipment conditions in the following examples are shown in table 1:

TABLE 1

The amounts of the components in the following examples are parts by weight (or parts by weight), each representing 10 g.

Example 1

The composition formulation of this example is shown in table 2.

The preparation method of the vulcanized rubber comprises the following steps:

first mixing:

setting the initial temperature of an internal mixer to be 70 ℃, rotating at 70rpm, adding a rubber substrate, a reinforcing agent, calcium sulfate whiskers, a vulcanization activator, an anti-aging agent and a plasticizer into the internal mixer to perform first mixing for 4min, discharging rubber, and standing for 4h to obtain master batch.

And (3) second mixing:

setting the initial temperature of the internal mixer to be 50 ℃, setting the rotating speed to be 60rpm, putting the master batch, the vulcanizing agent and the vulcanization accelerator into the internal mixer, mixing for 3min, and discharging rubber.

The compound obtained in the above manner was passed once through an open mill having a roll nip of 0.5mm and a roll temperature of 60. + -.5 ℃ and then the roll nip was adjusted to 5mm, and the obtained rubber compound was left for 24 hours after passing twice (in the following examples, the operating conditions in the open mill and the rubber compound holding time were all the same as in the present example, unless otherwise specified).

The rubber compound was sheeted in an open mill and vulcanized on a press vulcanizer under the vulcanization conditions shown in Table 2 to obtain a vulcanized rubber designated as S1.

Example 10

The formulation of the composition of this example is exactly the same as in example 1.

The preparation method of the vulcanized rubber comprises the following steps:

setting the initial temperature of an internal mixer to be 55 ℃, rotating at the speed of 60rpm, adding a rubber substrate, a reinforcing agent, calcium sulfate whiskers, a vulcanization activator, an anti-aging agent and a plasticizer into the internal mixer, mixing for 4min, lifting an upper ram of the internal mixer, adding masterbatch, a vulcanizing agent and a vulcanization accelerator into the internal mixer, dropping the upper ram of the internal mixer, continuously mixing for 3min, and discharging rubber. The rubber material obtained by the method is passed through an open mill with the roll spacing of 0.5mm and the roll temperature of 60 +/-5 ℃ for one time, then the roll spacing is adjusted to 5mm, and the obtained rubber compound is placed for 24 hours after two passes.

The rubber compound was sheeted on a mill and then vulcanized on a press under the vulcanization conditions shown in Table 2 to give a vulcanizate designated S10.

The remaining examples and comparative examples were carried out by the same procedure as in example 1, unless otherwise specified, and the formulations and specific process conditions of the respective examples are shown in Table 2.

TABLE 2

Table 2 (continuation 1)

Table 2 (continuation 2)

Table 2 (continuation 3)

Test example

Test examples are provided to illustrate the testing of properties of the vulcanizates.

(1) Mooney viscosity of the compounded rubber: the Mooney viscosity of the compounded rubber was measured by a Mooney viscometer according to the method specified in GB/T1232.1-2016, at a measuring temperature of 100 ℃ for a preheating time of 1min and for a measuring time of 4min, and the results of the measurement were expressed by ML (1+4) at 100 ℃ and are shown in Table 3.

(2) Tensile strength of vulcanized rubber: the tensile strength was tested by means of a universal tensile machine according to the method specified in GB/T528-2009, where the tensile rate was 500mm/min, the test temperature was 23 ℃, the effective part length of the test specimen was 25mm, and the width was 6 mm. For each set of samples, at least 3 replicates were run and the results were median and are shown in table 3.

(3) Compression set of vulcanized rubber: the compression set was measured according to the method specified in GB/T7759.1-2015, using a test specimen of property A, compression 25%, test temperature 100 ℃ and test time 70 h. For each set of samples, 3 replicates were tested and the results were median and are shown in table 3.

TABLE 3

It can be seen from the results in table 3 that the formulation of the present invention can compromise the processability and mechanical properties, compression set properties of the rubber composite as compared to the prior art.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.