Aging-resistant rubber gasket and method for manufacturing the same

Abstract

The application discloses an anti-aging rubber gasket and a preparation method thereof, and relates to the technical field of rubber gaskets. The anti-aging rubber gasket is prepared from the following raw materials in parts by mass: methyl vinyl silicone rubber green rubber 100 parts, fluorosilicone rubber 10-15 parts, reinforcing filler 30-60 parts, structure control agent 1-5 parts, heat-resistant additive 2-8 parts, crosslinking agent 0.5-3 parts, catalyst 0.1-1 part, and anti-aging agent 0.5-1.5 parts. The rubber gasket adopting the special anti-aging agent has a performance retention capacity which is obviously superior to that of a product using a traditional anti-aging agent and is far superior to that of a product without adding an anti-aging agent, and has a slower anti-aging attenuation trend.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rubber gaskets, and particularly relates to a kind of aging-resistant rubber gaskets and a preparation method thereof. BACKGROUND

[0002] As a key component for sealing, shock absorption and buffering, rubber gaskets are widely used in many fields such as mechanical manufacturing, automobile industry, electronic equipment, chemical pipeline and building waterproofing. The performance of rubber gaskets directly affects the sealing, stability and service life of equipment. Especially in harsh working conditions such as high temperature, humidity, strong ultraviolet radiation or chemical medium contact, the aging resistance becomes a core index to determine the application value of rubber gaskets.

[0003] In the prior art, rubber gaskets are usually prepared by using ordinary silicone rubber, nitrile rubber, fluorine rubber and other materials as base materials, and by adding conventional reinforcing fillers, anti-aging agents and other additives. However, traditional rubber gaskets are easily affected by heat, oxygen aging, ultraviolet aging and ozone aging during long-term use, which may cause problems such as cracking, hardening, loss of elasticity, and sealing failure. This not only increases the maintenance cost of equipment, but also may cause safety hazards such as leakage and failure.

[0004] In order to improve the aging resistance, the industry often uses the method of adding anti-aging agents for improvement. However, traditional anti-aging agents such as phenolic and amine compounds have defects such as poor compatibility with rubber base materials, easy migration and precipitation, and long-term protection effect decay, which cannot meet the long-term use requirements in complex working conditions. At the same time, the performance limitations of single rubber base material also restrict the improvement of the aging resistance of the gasket. For example, ordinary silicone rubber has limited heat resistance, pure fluorine rubber has high cost and poor processing performance, and the compatibility problem may occur during the mixing of base materials, which leads to unstable overall performance.

[0005] In addition, in the existing preparation process, problems such as uneven mixing, unreasonable vulcanization parameters and unscientific secondary vulcanization process may also cause defects in the internal structure of the rubber gasket, which further reduces its anti-aging ability. Therefore, it is an urgent technical problem to be solved in the industry to develop an aging-resistant rubber gasket with reasonable base material combination, efficient and stable anti-aging agent and optimized preparation process, to solve the problems of insufficient aging resistance and short service life of existing products. SUMMARY

[0006] The present application aims to solve the problems of insufficient aging resistance and rapid performance decline after aging in the prior art, and provides an aging-resistant rubber gasket and a preparation method thereof. The present application uses methyl vinyl silicone rubber as the base material, and optimizes the compatibility by adding fluorosilicone rubber. A new structure of anti-aging agent with formula 1 is used to solve the problem of easy migration of traditional anti-aging agents. Nitrogen protection mixing and stepwise secondary vulcanization process are combined to significantly improve the aging resistance, avoid internal structural defects, and obtain an aging-resistant rubber gasket with stable overall performance and long service life.

[0007] To achieve the above object, the technical scheme adopted by the present application is: an anti-aging rubber gasket is prepared from the following raw materials in parts by mass: methyl vinyl silicone rubber green rubber 100 parts, fluorosilicone rubber 10-15 parts, reinforcing filler 30-60 parts, structure control agent 1-5 parts, heat-resistant additive 2-8 parts, crosslinking agent 0.5-3 parts, catalyst 0.1-1 part, antioxidant 0.5-1.5 parts;

[0008] The structure of the antioxidant is shown in formula 1.

[0009] The structure of formula 1 is: ;

[0010] R1 in formula 1 is a substituent, and R1 is any one of methyl, methoxy, fluorine, and nitro.

[0011] Further, the reinforcing filler is fumed white carbon black.

[0012] Further, the structure control agent is at least one of hydroxyl silicone oil, diphenyl dimethoxysilane, and hexamethyldisilazane.

[0013] Further, the heat-resistant additive is at least one of iron oxide red, cerium oxide, and ferrite.

[0014] Further, the crosslinking agent is at least one of 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and dicumyl peroxide.

[0015] Further, the catalyst is a platinum-gold catalyst.

[0016] Further, the antioxidant is any one of the compounds shown in the following structures:

[0017] ;

[0018] .

[0019] A preparation method of an anti-aging rubber gasket, comprising the following steps:

[0020] S1. Mixing: the methyl vinyl silicone rubber green rubber, fluorosilicone rubber, antioxidant, structure control agent, and 1 / 2 mass fraction of reinforcing filler are put into a mixing mill, and mixed at 50-80℃ for 10-30 minutes; then 1 / 2 mass fraction of reinforcing filler and the heat-resistant additive are added, and mixing is continued for 20-50 minutes to obtain a rubber compound;

[0021] S2. Re-mixing and adding auxiliary agents: the rubber compound is re-mixed on an open mill, and is thin-passed and triangled for 3-5 times, then the cross-linking agent and the catalyst are sequentially added and uniformly mixed, and the rubber compound is sheeted, to obtain a rubber compound;

[0022] S3. Preforming and vulcanization: the rubber compound is placed in a mold, and is subjected to mold pressing vulcanization, with a vulcanization temperature of 150-180 DEG C, a vulcanization pressure of 10-20 MPa, and a vulcanization time of 5-15 minutes, to obtain a gasket embryo;

[0023] S4. Secondary vulcanization: the gasket embryo is placed in an oven, and is subjected to stepwise temperature rising secondary vulcanization, with a final temperature controlled at 180-220 DEG C, and a heat preservation time of 2-4 hours, to obtain the aging-resistant rubber gasket.

[0024] Further, the S1 is performed under a nitrogen atmosphere.

[0025] Further, the stepwise temperature rising secondary vulcanization in the S4 has the following specific procedure: the temperature is raised from room temperature to 100 DEG C at a rate of 1-2 DEG C / min, and is kept for 0.5 hours; then the temperature is raised to 150 DEG C at a rate of 1-2 DEG C / min, and is kept for 0.5 hours; finally, the temperature is raised to 200 DEG C at a rate of 1-2 DEG C / min, and is kept for 2 hours.

[0026] The present application solves the technical problems of insufficient aging resistance of existing rubber gaskets, easy migration of anti-aging agents, poor compatibility of base materials, and structural defects, etc. by the synergy of raw material formula: taking methyl vinyl silicone rubber raw rubber as the core base material, and matching fluorosilicone rubber to optimize the compatibility of the base material, which not only retains the basic performance of silicone rubber, but also makes up for the limitations of single base material in heat resistance or processability; using a special anti-aging agent with structure 1, which has stronger compatibility with the rubber base material, avoiding the problem of migration and precipitation of traditional anti-aging agents, and cooperating with heat-resistant additives such as iron oxide red and cerium oxide to resist heat, oxygen, ultraviolet and ozone aging in all directions; fumed silica as reinforcing filler, combined with structural control agents such as hydroxyl silicone oil, to improve the strength of the gasket while avoiding excessive structuring, and combined with precise proportioning of cross-linking agent and platinum catalyst to promote uniform cross-linking of the base material; cooperating with the segmented mixing process under a nitrogen atmosphere to ensure uniform dispersion of each component, and further optimizing the internal structure through subsequent stepwise secondary vulcanization to avoid defects, finally realizing the effect of significantly improving the aging resistance of the gasket, stable overall performance and prolonged service life.

[0027] Compared with the prior art, the present application has the following advantages:

[0028] 1. More excellent anti-aging performance: the rubber gasket using the special anti-aging agent of the present application has significantly better performance retention ability in ultraviolet, ozone and other aging environments than the product using traditional anti-aging agents, and is much better than the product without adding anti-aging agents, and has a slower anti-aging attenuation trend.

[0029] 2. Stable basic mechanical properties: the rubber gasket under the scheme of the application has stable overall basic tensile properties, and does not have obvious fluctuations due to the formula adjustment of anti-aging agent, base material matching and process optimization, and the mechanical property stability trend is good.

[0030] 3. Good performance consistency: between different embodiments (i.e. the special anti-aging agent of the application with different substituents), whether it is the basic tensile property or the performance retention after aging, it shows similar trend, and there is no large difference, which shows that the performance consistency and reliability trend of the technical scheme of the application are better. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The nuclear magnetic chart of the compound 3 described in the application.

[0032] Figure 2 The nuclear magnetic chart of the anti-aging agent 1 described in the application. DETAILED DESCRIPTION

[0033] The technical scheme of the application will be described clearly and completely in combination with the drawings in the application. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0034] Synthesis Example 1

[0035] Preparation of anti-aging agent 1:

[0036] ;

[0037] The CAS number of compound 1 is 7499-73-2;

[0038] The CAS number of compound 2 is 133921-27-4;

[0039] The CAS number of compound 4 is 688046-57-3;

[0040] Feeding section 1: under the protection of nitrogen, 5.00g of compound 1, 3.79g of compound 2 and 60ml of toluene solution were added into the dry reaction system in turn, and after stirring uniformly, 4.47g of potassium carbonate, 0.1g of palladium acetate and 0.1g of tri-tert-butyl phosphine were added in turn, and after stirring uniformly, the temperature was increased to 120℃, and refluxed for 12h;

[0041] Post-processing section 1: After the reaction, filter with diatomite while hot, collect the filtrate, remove the solvent with a rotary evaporator, purify with silica gel column chromatography, separate and purify with a mixture of petroleum ether and ethyl acetate as the eluent, remove the eluent with a rotary evaporator, and obtain 5.13 g of compound 3, mass spectrum MS+1: 415, nuclear magnetic resonance see Figure 1 ;

[0042] Feeding section 2: Under nitrogen protection, add 5.13 g of compound 3, 4.64 g of compound 4, and 60 ml of a mixed solvent of dioxane and diisopropylamine (40 ml / 20 ml) into the dry reaction system, add 0.09 g of palladium acetate, 0.17 g of 2-dicyclohexylphosphine-2',4',6'-triisopropyl biphenyl, and 0.07 g of CuI in sequence after stirring uniformly, stir uniformly, warm up to 90°C, and reflux for 5 h;

[0043] Post-processing section 2: After the reaction, filter after the temperature cools down to room temperature, wash the filter cake with tetrahydrofuran for 3 times, remove the solvent of the filtrate with a rotary evaporator, purify with silica gel column chromatography, separate and purify with a mixture of petroleum ether and ethyl acetate as the eluent, remove the eluent with a rotary evaporator, and obtain 6.37 g of antioxidant 1, mass spectrum MS+1: 710, nuclear magnetic resonance see Figure 2 .

[0044] Synthesis examples 2-4

[0045] Antioxidants 2-4 are sequentially synthesized in synthesis examples 2-4, and the preparation method of synthesis example 1 is referred to, wherein compound 2 is replaced, and the rest is the same as synthesis example 1. See Table 1 for details.

[0046] Table 1

[0047] Compound 2 Age resistor Synthesis Example 2 CAS No. 895518-65-7 Mass spectrometry MS+1: 726 Synthesis Example 3 CAS No. 122927-84-8 Mass spectrometry MS+1: 714 Synthesis Example 4 CAS No. 113305-56-9 Mass spectrometry MS+1: 741

[0048] Example 1

[0049] Preparation of an anti-aging rubber gasket:

[0050] 1. Principle components:

[0051] Methyl vinyl silicone rubber raw rubber: 100 parts, 110 raw rubber, molecular weight 60-70 x 10 4 ;

[0052] Fluorosilicone rubber: 12 parts, volatile matter 1.5%;

[0053] Reinforcing filler: fumed silica 45 parts;

[0054] Structural control agent: hydroxyl silicone oil 2 parts, hexamethyl disilazane 1 part (total 3 parts)

[0055] Heat-resistant additive: 3 parts of red iron oxide and 2 parts of cerium oxide (total 5 parts);

[0056] Crosslinking agent: 1.5 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane;

[0057] Catalyst: 0.5 parts of platinum gold catalyst (DX-3080 platinum gold catalyst);

[0058] Anti-aging agent: 1 part of anti-aging agent 1 prepared in Synthesis Example 1.

[0059] 2. Preparation method

[0060] S1. Mixing: Under the protection of a nitrogen atmosphere, 100 parts of methyl vinyl silicone rubber raw rubber, 12 parts of fluorosilicone rubber, 1 part of anti-aging agent 1, 3 parts of structure control agent (2 parts of hydroxyl silicone oil + 1 part of hexamethyldisilazane), and 22.5 parts of fumed silica were put into a mixer, and the temperature was controlled at 65°C, and mixed for 20 minutes; then 22.5 parts of remaining fumed silica and 5 parts of heat-resistant additive (3 parts of red iron oxide + 2 parts of cerium oxide) were added, and mixing was continued for 35 minutes to obtain a uniform rubber compound;

[0061] S2. Re-mixing and adding auxiliary agents: The above rubber compound was transferred to an open mill for re-mixing, and after thinning, it was packed into a triangle bag for 4 times, then 1.5 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 0.5 parts of platinum gold catalyst were added in turn, and the mixing was continued until the components were uniformly dispersed, and the sheet was obtained. Mixing rubber;

[0062] S3. Preforming and vulcanization: The mixing rubber was cut to the size suitable for the mold, and placed in a custom gasket mold for mold pressing vulcanization; the vulcanization temperature was controlled at 165°C, the vulcanization pressure was 15 MPa, and the vulcanization time was 10 minutes, and after vulcanization, the mold was removed, and a gasket embryo was obtained;

[0063] S4. Secondary vulcanization: The gasket embryo was placed in an oven and subjected to a stepwise temperature rising secondary vulcanization program: from room temperature to 100°C at a rate of 1.5°C / min, and kept for 0.5 hours; then heated to 150°C at a rate of 1.5°C / min, and kept for 0.5 hours; finally, heated to 200°C at a rate of 1.5°C / min, and kept for 2 hours; after the end of the heat preservation, the oven was naturally cooled to room temperature, and a kind of anti-aging rubber gasket was obtained.

[0064] Examples 2-4

[0065] A kind of anti-aging rubber gasket was prepared, referring to the preparation method of Example 1, the anti-aging agent therein was replaced with anti-aging agent 2-anti-aging agent 4 in turn, and the rest was the same as Example 1.

[0066] Comparative Example 1

[0067] A kind of preparation of anti-aging rubber gasket, with reference to the preparation method of example 1, the anti-aging agent in it is replaced with anti-aging agent D, the rest remains the same as example 1.

[0068] The CAS number of anti-aging agent D is: 135-88-6.

[0069] Comparative Example 2

[0070] A kind of preparation of anti-aging rubber gasket, with reference to the preparation method of example 1, the anti-aging agent in it is replaced with anti-aging agent MMB, the rest remains the same as example 1.

[0071] The CAS number of anti-aging agent MMB is: 53988-10-6.

[0072] Comparative Example 3

[0073] A kind of preparation of anti-aging rubber gasket, with reference to the preparation method of example 1, the anti-aging agent in it is replaced with anti-aging agent IPPD, the rest remains the same as example 1.

[0074] The CAS number of anti-aging agent IPPD is: 101-72-4.

[0075] Comparative Example 4

[0076] A kind of preparation of anti-aging rubber gasket, with reference to the preparation method of example 1, the anti-aging agent in it is not added, the rest remains the same as example 1.

[0077] Performance test:

[0078] The test sample is a kind of anti-aging rubber gasket prepared in example and comparative example.

[0079] 1. Tensile strength: test the tensile strength of the test sample according to the test method of GB / T 528-2009, the data is shown in Table 2;

[0080] 2. UV aging performance test: place the test sample in a UV aging box, light source: UVA-340 fluorescent UV lamp, irradiation intensity: 0.68 W / (m 2 ·nm), test cycle: irradiation 8h (60℃) + condensation 4h (50℃), total cycle 3000h, retest the tensile strength, calculate the tensile strength retention rate, the data is shown in Table 2;

[0081] 3. Ozone aging performance test: place the test sample in an ozone aging test box, ozone concentration: 50pphm, test temperature: 40℃, tensile deformation: 20% (static tensile state), aging time: 1000h, retest the tensile strength, calculate the tensile strength retention rate, the data is shown in Table 2.

[0082] Table 2

[0083] Tensile strength Mpa Ultraviolet aging tensile strength retention rate % Ozone aging tensile strength retention rate % Example 1 9.2 95.5 93.3 Example 2 9.5 96.1 94.7 Example 3 9.1 94.8 92.6 Example 4 9.3 95.2 93.9 Comparative Example 1 9.0 71.4 68.2 Comparative Example 2 9.1 68.7 66.5 Comparative Example 3 9.2 73.2 70.8 Comparative Example 4 9.0 35.5 33.0

[0084] The tensile strength of the examples (using the special antioxidant of the application) as a whole remains stable, and the tensile strength retention rate after ultraviolet aging and ozone aging presents a trend of being obviously superior to the comparative examples using the traditional antioxidant, and is much better than the comparative example without adding the antioxidant; the performance trends of different examples are similar, with little fluctuation, indicating that the special antioxidant of the application with different substituents can stably play an anti-aging role; the comparative example corresponding to the traditional antioxidant has a significantly weaker trend of strength retention rate after aging than the examples, and the comparative example without the antioxidant has the worst trend of strength retention rate after aging, highlighting the significant advantages of the special antioxidant of the application in improving the ultraviolet resistance and ozone resistance of the rubber gasket, and at the same time, it does not have a negative impact on the basic tensile properties.

[0085] Although embodiments of the application have been shown and described, it is to be understood that the application is not limited to the details of the foregoing embodiment, and that various changes in the form and details thereof can be made by those skilled in the art without departing from the spirit or scope of the application. The scope of the application is defined by the appended claims and their equivalents.

Claims

1. An age resistant rubber gasket characterized by, Prepared from the following raw materials by mass: methyl vinyl silicone rubber raw rubber 100 parts, fluorosilicone rubber 10-15 parts, reinforcing filler 30-60 parts, structure control agent 1-5 parts, heat-resistant additive 2-8 parts, crosslinking agent 0.5-3 parts, catalyst 0.1-1 part, antioxidant 0.5-1.5 parts; The structure of the antioxidant is shown in formula 1. The structure of Formula 1 is: ; R1 in formula 1 is a substituent, and R1 is any one of methyl, methoxy, fluorine, and nitro.

2. The weatherable rubber gasket of claim 1, wherein, The reinforcing filler is fumed white carbon black.

3. The weatherable rubber gasket of claim 1, wherein, The structure control agent is at least one of hydroxyl silicone oil, diphenyl dimethoxysilane, and hexamethyl disilazane.

4. The weatherable rubber gasket of claim 1, wherein, The heat-resistant additive is at least one of red iron oxide, cerium oxide, and ferrite.

5. The weatherable rubber gasket of claim 1, wherein, The crosslinking agent is at least one of 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-2,5-di(tert-butyl peroxy) hexane, and dicumyl peroxide.

6. The weatherable rubber gasket of claim 1, wherein, The catalyst is a platinum-gold catalyst.

7. The weatherable rubber gasket of claim 1, wherein, The antioxidant is any one of the compounds shown in the following structure: ； 。 8. A method of preparing an anti-aging rubber gasket according to any one of claims 1 to 7, characterized in that, Comprising the following steps: S1. Mixing: the methyl vinyl silicone rubber raw rubber, fluorosilicone rubber, antioxidant, structure control agent, and 1 / 2 mass fraction of reinforcing filler are put into a mixer and mixed at 50-80°C for 10-30 minutes; then 1 / 2 mass fraction of reinforcing filler and the heat-resistant additive are added, and mixing is continued for 20-50 minutes to obtain a rubber compound; S2. Remilling and adding additives: the rubber compound is remilled on an open mill, and thin-passed and packed into a triangle bag for 3-5 times, then the crosslinking agent and catalyst are added in turn, mixed uniformly, and sheeted to obtain a mixed rubber; S3. Preforming and vulcanization: the mixed rubber is placed in a mold for mold pressing vulcanization, the vulcanization temperature is 150-180°C, the vulcanization pressure is 10-20 MPa, and the vulcanization time is 5-15 minutes to obtain a gasket embryo; S4. Secondary vulcanization: the gasket embryo is placed in an oven for stepwise temperature rising secondary vulcanization, the final temperature is controlled at 180-220°C, and the temperature is maintained for 2-4 hours, and the gasket is obtained after furnace cooling.

9. The method for preparing an aging-resistant rubber gasket according to claim 8, characterized in that, The S1 is carried out under a nitrogen atmosphere.

10. The method of claim 8, wherein the antioxidant is selected from the group consisting of phenolic antioxidants, aminic antioxidants, phosphorous antioxidants, thio antioxidants, and mixtures thereof. The specific procedure for stepwise temperature rising secondary vulcanization in S4 is: from room temperature, the temperature is raised to 100°C at a rate of 1-2°C / min, and maintained for 0.5 hours; then the temperature is raised to 150°C at a rate of 1-2°C / min, and maintained for 0.5 hours; finally, the temperature is raised to 200°C at a rate of 1-2°C / min, and maintained for 2 hours.

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