A high-temperature resistant EPDM rubber sealing ring and its preparation method

Abstract

This invention relates to the field of rubber sealing ring technology, and proposes a high-temperature resistant EPDM rubber sealing ring and its preparation method. A high-temperature resistant EPDM rubber sealing ring comprises the following components in parts by weight: 100 parts EPDM rubber, 60-80 parts modified molybdenum disulfide, 30-50 parts paraffin oil, 4-8 parts activator, 1-3 parts antioxidant, 0.5-1.5 parts vulcanizing agent, and 2-3 parts accelerator; the modified molybdenum disulfide is molybdenum disulfide modified with phenoxyacetic anhydride. Through the above technical solution, the problem of poor high-temperature resistance of EPDM rubber in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of rubber sealing ring technology, specifically to a high-temperature resistant EPDM rubber sealing ring and its preparation method. Background Technology

[0002] Rubber sealing rings are pipe joint seals that utilize the elasticity and strength of rubber to achieve a sealing effect. They need to have good airtightness, water impermeability, wear resistance, heat resistance, and corrosion resistance.

[0003] Currently, materials used to manufacture rubber seals include natural rubber, styrene-butadiene rubber (SBR), chloroprene rubber, nitrile rubber (NBR), butyl rubber, ethylene propylene rubber (EPDM), and silicone rubber. Among these, EPDM is a copolymer of ethylene, propylene, and a small amount of dicyclopentadiene. Compared to other rubbers, the main chain of EPDM has a fully saturated structure, making it less prone to breakage under external energy or force. Therefore, it exhibits excellent weather resistance and aging resistance, along with high tensile strength and elongation, making it widely used in rubber seal materials. However, the current heat resistance of EPDM is insufficient for high-temperature applications, and its high-temperature performance needs further improvement. Summary of the Invention

[0004] This invention proposes a high-temperature resistant EPDM rubber sealing ring and its preparation method, which solves the problem of poor high-temperature resistance of EPDM rubber in related technologies.

[0005] The technical solution of the present invention is as follows:

[0006] A high-temperature resistant EPDM rubber sealing ring comprises the following components in parts by weight: 100 parts EPDM rubber, 60-80 parts modified molybdenum disulfide, 30-50 parts paraffin oil, 4-8 parts activator, 1-3 parts antioxidant, 0.5-1.5 parts vulcanizing agent, and 2-3 parts accelerator.

[0007] The modified molybdenum disulfide is molybdenum disulfide modified with phenoxyacetic anhydride.

[0008] As a further technical solution, the mass ratio of phenoxyacetic anhydride to molybdenum disulfide is 4~12:100.

[0009] As a further technical solution, the preparation method of the modified molybdenum disulfide includes the following steps: mixing phenoxyacetic anhydride-ethyl acetate solution with molybdenum disulfide, grinding, and drying to obtain modified molybdenum disulfide.

[0010] As a further technical solution, the mass-to-volume ratio of phenoxyacetic anhydride to ethyl acetate in the phenoxyacetic anhydride-ethyl acetate solution is 1~3g:10mL.

[0011] As a further technical solution, it also includes one of 4-methoxyphenylacetic anhydride, 2-ethylhexanoic anhydride, and trimethylacetic anhydride.

[0012] As a further technical solution, it also includes 3 to 8 parts of 2-ethylhexanoic anhydride.

[0013] As a further technical solution, the mass ratio of the modified molybdenum disulfide to 2-ethylhexanoic anhydride is 16:1.

[0014] As a further technical solution, the activator includes one or more of zinc oxide, stearic acid, and stearate;

[0015] The antioxidant includes one or more of antioxidants TMPPD, antioxidant MB, and antioxidant H;

[0016] The vulcanizing agent includes one or more of sulfur and peroxide;

[0017] The accelerator includes one or more of accelerator M, accelerator TAIC, and accelerator TAC.

[0018] The present invention also proposes a method for preparing a high-temperature resistant EPDM rubber sealing ring, comprising the following steps: mixing the components evenly and then vulcanizing to obtain a high-temperature resistant EPDM rubber sealing ring.

[0019] As a further technical solution, the mixing temperature is 50~70℃ and the mixing time is 15~30min;

[0020] The vulcanization temperature is 150~170℃, the vulcanization pressure is 10~15MPa, and the vulcanization time is 10~30min.

[0021] The working principle and beneficial effects of this invention are as follows:

[0022] 1. This invention uses molybdenum disulfide modified with phenoxyacetic anhydride to improve the high-temperature resistance of EPDM rubber sealing rings. In this invention, the modification of molybdenum disulfide with phenoxyacetic anhydride allows the molybdenum disulfide powder to become organic, preventing the agglomeration of molybdenum disulfide particles and helping to improve its compatibility with EPDM rubber, thereby improving the strength and high-temperature resistance of the EPDM rubber sealing ring.

[0023] 2. The present invention adds one of 4-methoxyphenylacetic anhydride, 2-ethylhexanoic anhydride, and trimethylacetic anhydride, which further improves the strength and high temperature resistance of EPDM rubber sealing rings. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] In the following examples and comparative examples, the EPDM rubber is EPDM 4760P; the molybdenum disulfide is 2000 mesh, 99.5 wt% industrial grade molybdenum disulfide; and the paraffin oil is paraffin oil 2280.

[0026] Example 1

[0027] S1. Preparation of modified molybdenum disulfide: Dissolve 8g of phenoxyacetic anhydride in 40mL of ethyl acetate to prepare a phenoxyacetic anhydride-ethyl acetate solution. Add the phenoxyacetic anhydride-ethyl acetate solution dropwise to 100g of molybdenum disulfide at a rate of 0.5mL / min. Grind the mixture and dry it at 55℃ to obtain modified molybdenum disulfide.

[0028] S2. 100 parts of EPDM rubber were successively added to a two-roll mill at 60°C with 70 parts of modified molybdenum disulfide, 40 parts of paraffin oil, 3 parts of zinc oxide, 3.5 parts of stearic acid, 2 parts of antioxidant MB, 1 part of benzoyl peroxide, and 2.5 parts of accelerator TAIC. After mixing for 20 minutes, the mixture was vulcanized at 160°C and 15MPa for 20 minutes to obtain an EPDM rubber sealing ring.

[0029] Example 2

[0030] S1. Preparation of modified molybdenum disulfide: Dissolve 4g of phenoxyacetic anhydride in 40mL of ethyl acetate to prepare a phenoxyacetic anhydride-ethyl acetate solution. Add the phenoxyacetic anhydride-ethyl acetate solution dropwise to 100g of molybdenum disulfide at a rate of 1mL / min. Grind the solution and dry it at 55℃ to obtain modified molybdenum disulfide.

[0031] S2. 100 parts of EPDM rubber are mixed on a two-roll mill at 50°C with 60 parts of modified molybdenum disulfide, 30 parts of paraffin oil, 2 parts of zinc oxide, 2 parts of magnesium stearate, 1 part of antioxidant H, 0.5 parts of sulfur, and 2 parts of accelerator M. After mixing for 30 minutes, the mixture is vulcanized at 150°C and 15MPa for 30 minutes to obtain an EPDM rubber sealing ring.

[0032] Example 3

[0033] S1. Preparation of modified molybdenum disulfide: Dissolve 12g of phenoxyacetic anhydride in 40mL of ethyl acetate to prepare a phenoxyacetic anhydride-ethyl acetate solution. Add the phenoxyacetic anhydride-ethyl acetate solution dropwise to 100g of molybdenum disulfide at a rate of 1.5mL / min. Grind the mixture and dry it at 55℃ to obtain modified molybdenum disulfide.

[0034] S2. 100 parts of EPDM rubber are mixed on a two-roll mill at 70°C with 80 parts of modified molybdenum disulfide, 50 parts of paraffin oil, 5 parts of zinc oxide, 3 parts of magnesium stearate, 3 parts of antioxidant TMPPD, 1.5 parts of benzoyl peroxide, and 3 parts of accelerator TAC. After mixing for 15 minutes, the mixture is vulcanized at 170°C and 10 MPa for 10 minutes to obtain an EPDM rubber sealing ring.

[0035] Example 4

[0036] S1. Preparation of modified molybdenum disulfide: Dissolve 8g of phenoxyacetic anhydride in 40mL of ethyl acetate to prepare a phenoxyacetic anhydride-ethyl acetate solution. Add the phenoxyacetic anhydride-ethyl acetate solution dropwise to 100g of molybdenum disulfide at a rate of 0.5mL / min. Grind the mixture and dry it at 55℃ to obtain modified molybdenum disulfide.

[0037] S2. 100 parts of EPDM rubber were successively added to a two-roll mill at 60°C with 70 parts of modified molybdenum disulfide, 3 parts of 4-methoxyphenylacetic anhydride, 40 parts of paraffin oil, 3 parts of zinc oxide, 3.5 parts of stearic acid, 2 parts of antioxidant MB, 1 part of benzoyl peroxide, and 2.5 parts of accelerator TAIC. After mixing for 20 minutes, the mixture was vulcanized at 160°C and 15MPa for 20 minutes to obtain an EPDM rubber sealing ring.

[0038] Example 5

[0039] S1. Preparation of modified molybdenum disulfide: Dissolve 8g of phenoxyacetic anhydride in 40mL of ethyl acetate to prepare a phenoxyacetic anhydride-ethyl acetate solution. Add the phenoxyacetic anhydride-ethyl acetate solution dropwise to 100g of molybdenum disulfide at a rate of 0.5mL / min. Grind the mixture and dry it at 55℃ to obtain modified molybdenum disulfide.

[0040] S2. 100 parts of EPDM rubber were successively added to a two-roll mill at 60°C with 70 parts of modified molybdenum disulfide, 3 parts of 2-ethylhexanoic anhydride, 40 parts of paraffin oil, 3 parts of zinc oxide, 3.5 parts of stearic acid, 2 parts of antioxidant MB, 1 part of benzoyl peroxide, and 2.5 parts of accelerator TAIC. After mixing for 20 minutes, the mixture was vulcanized at 160°C and 15MPa for 20 minutes to obtain an EPDM rubber sealing ring.

[0041] Example 6

[0042] S1. Preparation of modified molybdenum disulfide: Dissolve 8g of phenoxyacetic anhydride in 40mL of ethyl acetate to prepare a phenoxyacetic anhydride-ethyl acetate solution. Add the phenoxyacetic anhydride-ethyl acetate solution dropwise to 100g of molybdenum disulfide at a rate of 0.5mL / min. Grind the mixture and dry it at 55℃ to obtain modified molybdenum disulfide.

[0043] S2. 100 parts of EPDM rubber were successively added to a two-roll mill at 60°C with 70 parts of modified molybdenum disulfide, 3 parts of trimethylacetic anhydride, 40 parts of paraffin oil, 3 parts of zinc oxide, 3.5 parts of stearic acid, 2 parts of antioxidant MB, 1 part of benzoyl peroxide, and 2.5 parts of accelerator TAIC. After mixing for 20 minutes, the mixture was vulcanized at 160°C and 15MPa for 20 minutes to obtain an EPDM rubber sealing ring.

[0044] Example 7

[0045] S1. Preparation of modified molybdenum disulfide: Dissolve 8g of phenoxyacetic anhydride in 40mL of ethyl acetate to prepare a phenoxyacetic anhydride-ethyl acetate solution. Add the phenoxyacetic anhydride-ethyl acetate solution dropwise to 100g of molybdenum disulfide at a rate of 0.5mL / min. Grind the mixture and dry it at 55℃ to obtain modified molybdenum disulfide.

[0046] S2. 100 parts of EPDM rubber were successively added to a two-roll mill at 60°C with 70 parts of modified molybdenum disulfide, 5 parts of 2-ethylhexanoic anhydride, 40 parts of paraffin oil, 3 parts of zinc oxide, 3.5 parts of stearic acid, 2 parts of antioxidant MB, 1 part of benzoyl peroxide, and 2.5 parts of accelerator TAIC. After mixing for 20 minutes, the mixture was vulcanized at 160°C and 15MPa for 20 minutes to obtain an EPDM rubber sealing ring.

[0047] Example 8

[0048] S1. Preparation of modified molybdenum disulfide: Dissolve 8g of phenoxyacetic anhydride in 40mL of ethyl acetate to prepare a phenoxyacetic anhydride-ethyl acetate solution. Add the phenoxyacetic anhydride-ethyl acetate solution dropwise to 100g of molybdenum disulfide at a rate of 0.5mL / min. Grind the mixture and dry it at 55℃ to obtain modified molybdenum disulfide.

[0049] S2. 100 parts of EPDM rubber were successively added to a two-roll mill at 60°C with 70 parts of modified molybdenum disulfide, 8 parts of 2-ethylhexanoic anhydride, 40 parts of paraffin oil, 3 parts of zinc oxide, 3.5 parts of stearic acid, 2 parts of antioxidant MB, 1 part of benzoyl peroxide, and 2.5 parts of accelerator TAIC. After mixing for 20 minutes, the mixture was vulcanized at 160°C and 15MPa for 20 minutes to obtain an EPDM rubber sealing ring.

[0050] Comparative Example 1

[0051] 100 parts of EPDM rubber were mixed on a two-roll mill at 60°C with 70 parts of molybdenum disulfide, 40 parts of paraffin oil, 3 parts of zinc oxide, 3.5 parts of stearic acid, 2 parts of antioxidant MB, 1 part of benzoyl peroxide, and 2.5 parts of accelerator TAIC. After mixing for 20 minutes, the mixture was vulcanized at 160°C and 15MPa for 20 minutes to obtain EPDM rubber sealing rings.

[0052] The EPDM rubber sealing rings obtained in Examples 1-8 and Comparative Example 1 were subjected to tensile strength testing using type 1A dumbbell-shaped specimens in GB / T 528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber"; and the tensile strength of the rings was tested after aging at 125°C for 168 hours in a laminar flow air aging chamber according to method B1 in GB / T 3512-2014 "Accelerated Aging and Heat Resistance Test of Vulcanized Rubber or Thermoplastic Rubber in Hot Air"; the performance change rate was calculated; and the results are recorded in Table 1.

[0053] Table 1 High Temperature Resistance of EPDM Rubber Sealing Rings

[0054]

[0055] As can be seen from Table 1, the EPDM rubber sealing ring provided by the present invention has a tensile strength of over 20.0 MPa before aging and a tensile strength of over 18.9 MPa after aging at 125℃ for 168 hours, exhibiting high strength and excellent high-temperature resistance.

[0056] Compared with Comparative Example 1, Examples 1-8 used molybdenum disulfide modified with phenoxyacetic anhydride, while Comparative Example 1 did not modify molybdenum disulfide. The tensile strength and high temperature resistance of the EPDM rubber seals obtained in Examples 1-8 were better than those in Comparative Example 1, indicating that the use of molybdenum disulfide modified with phenoxyacetic anhydride can improve the strength and high temperature resistance of EPDM rubber seals.

[0057] Compared with Example 1, Examples 4-8 contain 4-methoxyphenylacetic anhydride, Examples 5 and 7-8 contain 2-ethylhexanoic anhydride, and Example 6 contains trimethylacetic anhydride. The tensile strength and high-temperature resistance of the EPDM rubber seals obtained in Examples 4-8 are higher than those in Example 1. This indicates that by adding 4-methoxyphenylacetic anhydride, 2-ethylhexanoic anhydride, or trimethylacetic anhydride to the molybdenum disulfide modified with phenoxyacetic anhydride, the strength and high-temperature resistance of the EPDM rubber seals can be further improved.

[0058] The EPDM rubber sealing ring obtained in Example 1 was subjected to aging life test according to HG / T 3087-2001 "Rapid Determination Method for Storage Period of Static Sealing Rubber Parts" (Test items: compression set 1-C%, compression ratio: 42%, test medium: water, critical value: y=0.4), and the test results are recorded in Table 2.

[0059] Table 2 Aging life of EPDM rubber seals

[0060]

[0061] As can be seen from Table 2, the EPDM rubber sealing ring provided by the present invention has excellent high temperature resistance and a long service life.

[0062] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature resistant EPDM rubber sealing ring, characterized in that, The composition includes the following components in parts by weight: 100 parts EPDM rubber, 60-80 parts modified molybdenum disulfide, 30-50 parts paraffin oil, 4-8 parts activator, 1-3 parts antioxidant, 0.5-1.5 parts vulcanizing agent, 2-3 parts accelerator, and 3-8 parts 2-ethylhexanoic anhydride. The modified molybdenum disulfide is molybdenum disulfide modified with phenoxyacetic anhydride, and the mass ratio of phenoxyacetic anhydride to molybdenum disulfide is 4~12:

100.

2. The high-temperature resistant EPDM rubber sealing ring according to claim 1, characterized in that, The method for preparing the modified molybdenum disulfide includes the following steps: mixing phenoxyacetic anhydride-ethyl acetate solution with molybdenum disulfide, grinding, and drying to obtain modified molybdenum disulfide.

3. The high-temperature resistant EPDM rubber sealing ring according to claim 2, characterized in that, The mass-to-volume ratio of phenoxyacetic anhydride to ethyl acetate in the phenoxyacetic anhydride-ethyl acetate solution is 1~3g:10mL.

4. The high-temperature resistant EPDM rubber sealing ring according to claim 1, characterized in that, The mass ratio of the modified molybdenum disulfide to 2-ethylhexanoic anhydride is 16:

1.

5. The high-temperature resistant EPDM rubber sealing ring according to claim 1, characterized in that, The activator includes one or more of zinc oxide, stearic acid, and stearate; The antioxidant includes one or more of antioxidants TMPPD, antioxidant MB, and antioxidant H; The vulcanizing agent includes one or more of sulfur and peroxide; The accelerator includes one or more of accelerator M, accelerator TAIC, and accelerator TAC.

6. A method for preparing a high-temperature resistant EPDM rubber sealing ring according to any one of claims 1 to 5, characterized in that, Includes the following steps: After the components are mixed evenly, they are vulcanized to obtain a high-temperature resistant EPDM rubber sealing ring.

7. The method for preparing a high-temperature resistant EPDM rubber sealing ring according to claim 6, characterized in that, The mixing temperature is 50~70℃, and the mixing time is 15~30min; The vulcanization temperature is 150~170℃, the vulcanization pressure is 10~15MPa, and the vulcanization time is 10~30min.

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