1. A composition based on butyl rubber and nitrile rubber, characterized in that it contains the following components stored in admixture or independently:

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

in the rubber matrix, the content weight ratio of the nitrile rubber to the butyl rubber is 9:1 to 7: 3;

the content of the carbon black is 40-140 parts by weight and the content of the white carbon black is 10-35 parts by weight relative to 100 parts by weight of the rubber matrix; the calcium sulfate whisker is 5-35 parts by weight, the vulcanizing agent is 0.4-1.5 parts by weight, the vulcanization accelerator is 1.5-6 parts by weight, the vulcanization activator is 2-20 parts by weight, the anti-aging agent is 0-12 parts by weight, and the plasticizer is 0-45 parts by weight.

2. The composition according to claim 1, wherein the carbon black is contained in an amount of 60 to 100 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 10 to 30 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, a Mooney viscosity ML (1+4) at 100 ℃ of 30 to 100;

preferably, the butyl rubber has an unsaturation of 1.5 to 2.0% and a Mooney viscosity ML (1+8) of 40 to 55 at 100 ℃.

5. The composition according to any one of claims 1 to 4, wherein the carbon black is contained in an amount of 60 to 100 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 10-30 parts by weight, the vulcanizing agent is 0.5-1.2 parts by weight, the vulcanization accelerator is 1.5-6 parts by weight, the vulcanization activator is 5-12 parts by weight, the anti-aging agent is 2-8 parts by weight, and the plasticizer is 10-30 parts by weight.

6. Composition according to any one of claims 1 to 5, wherein the vulcanizing agent is selected from at least one of sulfur donors, preferably the vulcanizing agent is sulfur;

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

preferably, the vulcanization accelerator is a thiuram-type accelerator or a dithiocarbamate-type accelerator, and the content of the vulcanization accelerator is 1.5 to 4 parts by weight relative to 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 0.5 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;

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 4 to 8 parts by weight and the stearic acid is present in an amount of 1 to 4 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.

7. A method of preparing a vulcanizate, the method comprising: mixing the components of the composition of any one of claims 1 to 6 to form a mix, and subjecting the mix to a vulcanization treatment.

8. The method of claim 7, wherein the act of mixing the components comprises the steps of:

(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 60-90 deg.C, and the time is 4-6 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 any one of claims 7-9, wherein the conditions of the sulfidation treatment comprise: 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 90 to 300 s.

11. A vulcanized rubber produced by the method of any one of claims 7 to 10.

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

Background

High air tightness is one of important performance indexes of sealing materials, and is widely applied to the field of durable vacuum sealing. Although the nitrile rubber sealing material has better air tightness, the requirement of the product on the air tightness can not be met in the special high-end application field. The butyl rubber has low molecular chain movement capacity due to the existence of dense lateral methyl groups in the molecular chain, and is a rubber variety with the best air tightness in general rubber, so that the sealing material prepared by blending the nitrile rubber and the butyl rubber has the advantage of preparing a high-performance rubber sealing material which gives consideration to the respective advantages of the two rubbers.

However, the preparation of sealing materials by blending nitrile rubber and butyl rubber still presents a series of problems: firstly, because the difference between the polarities of the two rubbers is large, the blending ratio of the two rubbers needs to be strictly controlled in the blending process, and the composite material is phase separated due to poor compatibility of the two base materials when the dosage of the butyl rubber is too large, so that the material performance is seriously influenced; if the amount of the butyl rubber is too small, the purpose of improving the air tightness of the composite material cannot be fully achieved. Secondly, due to the processing characteristic of high-temperature and rapid vulcanization of the sealing material, the processing performance and the application performance of the composite material cannot be considered under a normal matching system.

In the field of rubber sealing materials, particularly rubber sealing materials using nitrile rubber as a matrix, related reports are already provided in many journals and patents.

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 present invention has an object to provide a rubber composition having good processability, a moderate Mooney viscosity of the rubber compound and suitable for application to a high-efficiency high-temperature rapid vulcanization production process, in order to obtain a vulcanized rubber having excellent mechanical properties, compression set resistance and airtightness suitable for use as, for example, a sealing material or the like.

In order to achieve the above object, a first aspect of the present invention provides a composition based on butyl rubber and nitrile rubber, 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 and a vulcanization activator, and optionally contains an anti-aging agent and/or a plasticizer, wherein the rubber matrix is the combination of nitrile rubber and butyl rubber, and the reinforcing agent is the combination of carbon black and white carbon black;

in the rubber matrix, the content weight ratio of the nitrile rubber to the butyl rubber is 9:1 to 7: 3;

the content of the carbon black is 40-140 parts by weight and the content of the white carbon black is 10-35 parts by weight relative to 100 parts by weight of the rubber matrix; the calcium sulfate whisker is 5-35 parts by weight, the vulcanizing agent is 0.4-1.5 parts by weight, the vulcanization accelerator is 1.5-6 parts by weight, the vulcanization activator is 2-20 parts by weight, the anti-aging agent is 0-12 parts by weight, and the plasticizer is 0-45 parts by weight.

A second aspect of the present invention provides a method for preparing a vulcanized rubber, the method comprising: the components in the composition are mixed to form a mixed rubber, and then the mixed rubber 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 combination of the nitrile rubber and the butyl rubber is used as a rubber matrix, the carbon black and the white carbon black in specific parts by weight are used as reinforcing agents, the inorganic filler calcium sulfate whisker in a certain part by weight is filled, and the vulcanizing agent, the vulcanization accelerator and the vulcanization activator in specific parts are used in a matching manner, so that the prepared rubber composition gross rubber has good processability and moderate gross rubber Mooney viscosity, is suitable for being applied to a production process of high-temperature rapid vulcanization, and the prepared vulcanized rubber has excellent mechanical property, compression permanent deformation resistance and airtightness.

In particular, compared with the scheme of singly using the nitrile rubber as the rubber matrix, the invention adopts the combination of the nitrile rubber and the butyl rubber as the matrix material, and can realize obvious improvement of air tightness on the premise of keeping the processing performance and the mechanical property equivalent to those of the nitrile rubber and slightly improving the compression permanent deformation.

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 indicated, a first aspect of the present invention provides a composition based on butyl rubber and nitrile rubber, 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 and a vulcanization activator, and optionally contains an anti-aging agent and/or a plasticizer, wherein the rubber matrix is the combination of nitrile rubber and butyl rubber, and the reinforcing agent is the combination of carbon black and white carbon black;

in the rubber matrix, the content weight ratio of the nitrile rubber to the butyl rubber is 9:1 to 7: 3;

the content of the carbon black is 40-140 parts by weight and the content of the white carbon black is 10-35 parts by weight relative to 100 parts by weight of the rubber matrix; the calcium sulfate whisker is 5-35 parts by weight, the vulcanizing agent is 0.4-1.5 parts by weight, the vulcanization accelerator is 1.5-6 parts by weight, the vulcanization activator is 2-20 parts by weight, the anti-aging agent is 0-12 parts by weight, and the plasticizer is 0-45 parts by weight.

In order to provide better processability to the rubber compound prepared from the composition of the present invention and further provide more excellent mechanical properties, compression set resistance and air tightness to the vulcanized rubber obtained therefrom, it is more preferable that the carbon black is contained in an amount of 60 to 100 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 10 to 30 parts by weight with respect 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.

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 butyl rubber has an unsaturation of 1.5 to 2.0% and a Mooney viscosity ML (1+8) of 40 to 55 at 100 ℃.

The unsaturation of the butyl rubber according to the invention is obtained according to the nuclear magnetic resonance method, unless otherwise specified.

Preferably, the content of the carbon black is 60 to 100 parts by weight and the content of the white carbon black is 15 to 30 parts by weight relative to 100 parts by weight of the rubber matrix; the calcium sulfate whisker is 10-30 parts by weight, the vulcanizing agent is 0.5-1.2 parts by weight, the vulcanization accelerator is 1.5-6 parts by weight, the vulcanization activator is 5-12 parts by weight, the anti-aging agent is 2-8 parts by weight, and the plasticizer is 10-30 parts by weight.

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

Preferably, the vulcanization accelerator is selected from at least one of thiuram type accelerators, dithiocarbamate type accelerators and sulfenamide type accelerators.

According to a preferred embodiment, the vulcanization accelerator is a thiuram-type accelerator or a dithiocarbamate-type accelerator, and in this preferred case, the vulcanization accelerator is contained in an amount of 1.5 to 4 parts by weight per 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 0.5 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 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.

According to a particularly preferred embodiment, the zinc oxide is present in an amount of 4 to 8 parts by weight and the stearic acid in an amount of 1 to 4 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 thus better mechanical properties, compression set resistance and air tightness 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 60-90 deg.C, and the time is 4-6 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 90 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 third 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 higher 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, compression permanent deformation resistance and air tightness.

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 ℃;

rubber matrix-butyl rubber: no. 1751, unsaturation degree of 1.7%, Mooney viscosity ML (1+8) at 100 ℃ of 51, produced by Beijing Yanshan division of Petroselinum, China petrochemical;

rubber matrix-butyl rubber: trade name EB365, unsaturation 2.0%, Mooney viscosity ML (1+8) at 100 ℃ 40, manufactured by EXXON, USA;

rubber matrix-butyl rubber: a designation 268, unsaturation degree of 1.5%, Mooney viscosity ML (1+8) at 100 ℃ of 55, manufactured by EXXON corporation, USA;

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 (than)Surface area of 73m²/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

Serial number	Device name	Model number	Manufacturer of the product
				1	Internal mixer	BR1600	Farrel America Ltd
2	Open mill	XK-160	Qingdao Xincheng Yiming mechanical Co Ltd
				3	Flat vulcanizing machine	XLB-D400*400*2	Shanghai first rubber machinery plant
4	Universal tensile machine	GT-AT-3000	Taiwan high speed railway Co
				5	Mooney viscometer	SMV-300	Taiwan high speed railway Co
6	Differential pressure method gas permeameter	TMVAC-V2	JINAN LABTHINK MECHANICAL AND ELECTRICAL TECHNOLOGY Co.,Ltd.

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.

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

Example 10

The formulation of the composition used in this example is identical to the formulation of the composition in example 1, except that the process for preparing the vulcanizate is different from that in example 1, specifically:

setting the initial temperature of an internal mixer to be 60 ℃, rotating at the speed of 70rpm, adding a rubber matrix, carbon black, white carbon black, calcium sulfate whiskers, a vulcanization activator, an anti-aging agent and a plasticizer into the internal mixer for mixing for 5min, lifting an upper top plug of the internal mixer, adding masterbatch, a vulcanizing agent and a vulcanization accelerator into the internal mixer, dropping the upper top plug of the internal mixer, continuing 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.

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.

(4) Airtightness: an automatic air permeability tester is adopted to measure the air permeability coefficient of vulcanized rubber according to ISO 2782, and test gas N₂The test temperature is 23 ℃, and the test sample is a circular thin slice with the diameter of 8cm and the thickness of 1 mm.

TABLE 3

It can be seen from the results in table 3 that, compared with the prior art, the formulation of the present invention can both significantly improve the tensile strength and elongation at break of the rubber composite; the permeability coefficient is lower, and the air tightness is excellent; and the compression set is lower.

The rubber sealing material composition provided by the invention has low Mooney viscosity, and is beneficial to molding and processing.

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.