Heat-aging-resistant rubber material for sealing ring and preparation method of heat-aging-resistant rubber material

Abstract

The invention provides a heat-aging-resistant rubber material for a sealing ring and a preparation method of the heat-aging-resistant rubber material. The rubber material comprises the following raw materials in parts by weight: 100 parts of nitrile rubber, 15-35 parts of silicone rubber, 20-40 parts of a reinforcing agent, 4-10 parts of a heat-aging-resistant agent, 1-3 parts of a vulcanizing agent, 2-6 parts of a vulcanization accelerator, 0.5-2 parts of an activating agent and 1-5 parts of a plasticizer. The heat-resistant aging agent is a POSS (Polyhedral Oligomeric Silsesquioxane) polymer containing hindered amine groups. According to the heat-aging-resistant rubber material for the sealing ring and the preparation method of the heat-aging-resistant rubber material, the rubber material has excellent heat aging resistance, and the requirements of long service time and low replacement frequency when the rubber material is used for the sealing ring can be effectively met.

Description

Technical Field

[0001] The invention relates to the technical field of rubber materials, and in particular to a heat-resistant aging rubber material for a sealing ring and a preparation method thereof. Background Art

[0002] Nitrile rubber is an important component of rubber materials and is widely used in the field of rubber materials for sealing rings. It has good oil resistance, but its structure contains unsaturated olefin segments, which leads to its brittleness and poor aging resistance, which is not conducive to long-term use.

[0003] The aging problem of nitrile rubber products greatly reduces their service life, especially in some harsh environments (such as high temperature, high pressure, acidic, alkaline and oily environments), which will further shorten the service life of nitrile rubber products and increase the cost of use. In order to improve the heat aging resistance of nitrile rubber products, various rubber antioxidants are usually used in nitrile rubber. However, most of the nitrile rubber antioxidants currently used are small molecules, which are easy to escape from the rubber matrix during production and use. On the one hand, it reduces the anti-aging effect of rubber products, and on the other hand, it brings about environmental pollution and other problems. Summary of the invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a heat-resistant aging rubber material for a sealing ring and a preparation method thereof. The rubber material has excellent heat-resistant aging performance and can effectively meet the requirements of long service life and low replacement frequency when used for a sealing ring.

[0005] The invention discloses a heat-resistant aging rubber material for a sealing ring, comprising the following raw materials in parts by weight: 100 parts of nitrile rubber, 15-35 parts of silicone rubber, 20-40 parts of a reinforcing agent, 4-10 parts of a heat-resistant aging agent, 1-3 parts of a vulcanizing agent, 2-6 parts of a vulcanization accelerator, 0.5-2 parts of an activator, and 1-5 parts of a plasticizer; the heat-resistant aging agent is a POSS polymer containing a hindered amine group.

[0006] In the present invention, the rubber material formula of the sealing ring is optimized, specifically by cooperating with the rubber matrix, anti-aging system, reinforcing filling system, vulcanization system and other auxiliary agent systems to improve the thermal stability, thereby improving the heat aging resistance of the sealing ring.

[0007] Preferably, the POSS polymer containing hindered amine groups is prepared by the following method: a siloxane containing hindered amine groups and a siloxane containing amino groups are subjected to a hydrolysis condensation reaction to obtain a caged silsesquioxane POSS, the caged silsesquioxane POSS is subjected to a condensation reaction with 2-bromoisobutyryl bromide, and then subjected to an atom transfer radical polymerization reaction with 4-cyanostyrene to obtain the POSS polymer containing hindered amine groups.

[0008] Preferably, the structural formula of the siloxane containing hindered amine groups is as follows:

[0009]

[0010] The structural formula of the amino group-containing siloxane is as follows:

[0011]

[0012] Preferably, the weight ratio of the hindered amine group-containing siloxane, the amino group-containing siloxane and 4-cyanostyrene is 1:0.1-0.2:1.5-2.

[0013] In the present invention, after the siloxane containing hindered amine groups and the siloxane containing amino groups are hydrolyzed and condensed, a caged silsesquioxane POSS containing both hindered amine groups and amino groups is obtained. The amino groups on the caged silsesquioxane POSS can undergo an amide condensation reaction with 2-bromoisobutyryl bromide to obtain a caged silsesquioxane POSS containing a bromine initiator. The caged silsesquioxane POSS can undergo an atom transfer radical polymerization reaction with 4-cyanostyrene to obtain a polymer of cyanostyrene grafted onto the caged silsesquioxane. The structure thereof is schematically shown as follows: Figure 1 shown.

[0014] In the present invention, a POSS polymer containing a hindered amine group is used as a heat-resistant aging agent. On the one hand, the hindered amine group contained in the POSS polymer is used as a light and heat stabilizer with excellent performance, has a good inhibitory effect on the light, heat and oxygen degradation reaction of nitrile rubber, and can capture free radical intermediates generated in the rubber aging process, so the aging process of the rubber can be inhibited, the tolerance of the corresponding rubber material to high and low temperature changes after being used in the sealing ring is improved, and the service life of the sealing ring is extended; on the other hand, the cyanostyrene polymer structure contained in the POSS polymer containing the hindered amine group is similar to the structure of the nitrile rubber, and the two have good compatibility, thereby being more conducive to the dispersion of the POSS polymer containing the hindered amine group in the rubber matrix, improving the dispersibility of the heat-resistant aging agent in the nitrile rubber, and enhancing the effect of inhibiting the aging of the rubber.

[0015] Preferably, the acrylonitrile content in the nitrile rubber is 25-40%, and the silicone rubber is methyl vinyl silicone rubber.

[0016] Preferably, the reinforcing agent is at least one of high wear-resistant carbon black, semi-reinforcing carbon black, fast extrusion carbon black, calcium bicarbonate, diatomaceous earth or white carbon black.

[0017] Preferably, the vulcanizing agent is at least one of sulfur, bis-25 or BIBP.

[0018] Preferably, the vulcanization accelerator is at least one of accelerator M, accelerator DM, accelerator TMTD, accelerator CBS or accelerator TETD.

[0019] Preferably, the activator is an oxide and stearic acid, and the oxide is zinc oxide and / or magnesium oxide.

[0020] Preferably, the plasticizer is at least one of dioctyl phthalate, diisononyl phthalate, trioctyl trimellitate or (butoxyethoxyethyl) adipate.

[0021] The present invention also proposes a method for preparing the heat-resistant aging rubber material for the sealing ring, comprising: mixing nitrile rubber and silicone rubber evenly by weight, then adding a reinforcing agent, a heat-resistant aging agent, an activator and a plasticizer and mixing evenly, adding a vulcanizing agent and a vulcanization accelerator after rubber removal and mixing evenly to obtain a final rubber mix; vulcanizing the final rubber mix to obtain a finished product, namely the heat-resistant aging rubber material for the sealing ring.

[0022] In the heat-resistant aging rubber material for sealing ring of the present invention, nitrile rubber as the main raw material has excellent air tightness, and silicone rubber as the compound rubber matrix has good corrosion resistance, solvent resistance, oil resistance, weather resistance and elasticity, etc., and the two can be combined to obtain a good sealing effect; the heat-resistant aging agent is a POSS polymer containing a hindered amine group, which is an anti-aging agent with multiple anti-aging functions, and can effectively improve the tolerance of the sealing ring to high and low temperature changes, etc., and extend the service life of the sealing ring. The present invention utilizes the compounding and synergistic effect of each raw material, so that the obtained rubber sealing ring material has good sealing performance, high mechanical properties, good heat aging resistance, etc., excellent comprehensive performance, and has strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 The structural formula of the heat aging agent is DETAILED DESCRIPTION

[0023] The technical solutions of the present invention are described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustration only and are not to be construed as limiting the scope of the present invention.

[0024] Example 1

[0025] A heat-resistant aging rubber material for a sealing ring, comprising the following raw materials in parts by weight: 100 parts of nitrile rubber (model NBR2850), 25 parts of silicone rubber (methyl vinyl silicone rubber, model 110-2 / 2S), 30 parts of a reinforcing agent (high wear-resistant carbon black N375), 7 parts of a heat-resistant aging agent, 2 parts of a vulcanizing agent (the weight ratio of sulfur to vulcanizing agent di-25 is 1:1), 4 parts of a vulcanizing accelerator (the weight ratio of accelerator M to accelerator TMTD is 1:1), 1 part of an activator (the weight ratio of zinc oxide to stearic acid is 1:1), and 3 parts of a plasticizer (dioctyl phthalate);

[0026] The heat aging resistant agent is a POSS polymer containing a hindered amine group, which is prepared by the following method: adding a siloxane containing a hindered amine group and a siloxane containing an amino group to methanol, stirring and mixing them evenly, then adding ammonia water (25%), wherein the weight ratio of the siloxane containing a hindered amine group, the siloxane containing an amino group and the ammonia water is 1:0.15:0.05, heating to 80°C and stirring for 6 hours, filtering, washing, and drying to obtain a caged silsesquioxane POSS; adding the caged silsesquioxane POSS to anhydrous methanol, then adding triethylamine and stirring evenly, and then adding 2-bromoisobutyryl bromide, wherein the siloxane containing a hindered amine group, triethylamine and 2-bromoisobutyryl bromide are The weight ratio of the siloxane containing hindered amine groups, pentamethyldiethylenetriamine, 4-cyanostyrene and cuprous bromide is 1:0.06:1.8:0.05, and the mixture is heated to 60°C under nitrogen protection and stirred for 12 hours, and then centrifuged, washed and dried to obtain a POSS polymer containing hindered amine groups, which is the heat-resistant aging agent;

[0027] The structural formula of the siloxane containing hindered amine groups is as follows:

[0028]

[0029] The structural formula of the amino group-containing siloxane is as follows:

[0030]

[0031] The structural formula of the heat aging resistant agent is as follows Figure 1 shown.

[0032] The preparation method of the heat-resistant aging rubber material for the sealing ring comprises:

[0033] Add nitrile rubber and silicone rubber according to the above weight parts into an open mill and mix them evenly. After heating to 90°C, add a reinforcing agent, a heat-resistant aging agent, an activator and a plasticizer and mix them evenly. Then add a vulcanizing agent and a vulcanization accelerator and mix them evenly. After pressing into thin sheets, a final rubber mix is ​​obtained. The final rubber mix is ​​placed in a molding mold for molding, and is vulcanized at a pressure of 16 MPa and a temperature of 170°C for 15 minutes. After opening the mold, the heat-resistant aging rubber material for the sealing ring is obtained.

[0034] Example 2

[0035] A heat-resistant aging rubber material for a sealing ring, comprising the following raw materials in parts by weight: 100 parts of nitrile rubber (model NBR2850), 15 parts of silicone rubber (methyl vinyl silicone rubber, model 110-2 / 2S), 40 parts of a reinforcing agent (high wear-resistant carbon black N375), 4 parts of a heat-resistant aging agent, 3 parts of a vulcanizing agent (the weight ratio of sulfur to vulcanizing agent di-25 is 1:1), 2 parts of a vulcanizing accelerator (the weight ratio of accelerator DM to accelerator TMTD is 1:1), 2 parts of an activator (the weight ratio of zinc oxide to stearic acid is 1:1), and 1 part of a plasticizer (diisononyl phthalate);

[0036] The heat aging resistant agent is a POSS polymer containing hindered amine groups, which is prepared according to the method described in Example 1.

[0037] The preparation method of the heat-resistant aging rubber material for the sealing ring is according to the method described in Example 1.

[0038] Example 3

[0039] A heat-resistant aging rubber material for a sealing ring, comprising the following raw materials in parts by weight: 100 parts of nitrile rubber (model NBR2850), 35 parts of silicone rubber (methyl vinyl silicone rubber, model 110-2 / 2S), 20 parts of a reinforcing agent (high wear-resistant carbon black N375), 10 parts of a heat-resistant aging agent, 1 part of a vulcanizing agent (the weight ratio of sulfur to the vulcanizing agent BIBP is 1:1), 6 parts of a vulcanizing accelerator (the weight ratio of an accelerator M to an accelerator TMTD is 1:1), 0.5 parts of an activator (the weight ratio of zinc oxide to stearic acid is 1:1), and 5 parts of a plasticizer (trioctyl trimellitate);

[0040] The heat aging resistant agent is a POSS polymer containing hindered amine groups, which is prepared according to the method described in Example 1.

[0041] The preparation method of the heat-resistant aging rubber material for the sealing ring is according to the method described in Example 1.

[0042] Comparative Example 1

[0043] A heat-resistant aging rubber material for a sealing ring comprises the following raw materials in parts by weight: 100 parts of nitrile rubber (model NBR2850), 25 parts of silicone rubber (methyl vinyl silicone rubber, model 110-2 / 2S), 30 parts of a reinforcing agent (high wear-resistant carbon black N375), 7 parts of a heat-resistant aging agent (the weight ratio of antioxidant 4010NA to antioxidant RD is 1:1), 2 parts of a vulcanizing agent (the weight ratio of sulfur to vulcanizing agent di-25 is 1:1), 4 parts of a vulcanization accelerator (the weight ratio of accelerator M to accelerator TMTD is 1:1), 1 part of an activator (the weight ratio of zinc oxide to stearic acid is 1:1), and 3 parts of a plasticizer (dioctyl phthalate).

[0044] The preparation method of the heat-resistant aging rubber material for the sealing ring is according to the method described in Example 1.

[0045] Comparative Example 2

[0046] A heat-resistant aging rubber material for a sealing ring, comprising the following raw materials in parts by weight: 100 parts of nitrile rubber (model NBR2850), 25 parts of silicone rubber (methyl vinyl silicone rubber, model 110-2 / 2S), 30 parts of a reinforcing agent (high wear-resistant carbon black N375), 7 parts of a heat-resistant aging agent, 2 parts of a vulcanizing agent (the weight ratio of sulfur to vulcanizing agent di-25 is 1:1), 4 parts of a vulcanizing accelerator (the weight ratio of accelerator M to accelerator TMTD is 1:1), 1 part of an activator (the weight ratio of zinc oxide to stearic acid is 1:1), and 3 parts of a plasticizer (dioctyl phthalate);

[0047] The heat aging resistant agent is POSS containing hindered amine groups, which is prepared by the following method: adding siloxane containing hindered amine groups to methanol and stirring and mixing evenly, then adding ammonia water (25%), wherein the weight ratio of siloxane containing hindered amine groups to ammonia water is 1:0.05, heating to 80° C. and stirring and reacting for 6 hours, filtering, washing, and drying to obtain POSS containing hindered amine groups, namely the heat aging resistant agent;

[0048] The structural formula of the siloxane containing hindered amine groups is as follows:

[0049]

[0050] The preparation method of the heat-resistant aging rubber material for the sealing ring is according to the method described in Example 1.

[0051] The sealing rings obtained in the embodiments and comparative examples were prepared and tested using heat-resistant aging rubber materials according to standard test samples. The performance test results are shown in Table 1 below.

[0052] Among them, the test methods and standards involved are as follows:

[0053] The Shore A hardness is tested according to GB / T 531.1-2008; the tensile strength is tested according to GB / T 528-2009; the tear strength is tested according to GB / T 529-2008; the compression set is tested according to GB / T 7759.1-2015; the heat aging resistance is tested by aging the sample in a hot air aging box at 250°C for 70 hours, and then the tensile strength and elongation at break are tested again according to the same standard.

[0054] Table 1 Test results of heat aging resistant rubber materials described in Examples and Comparative Examples

[0055]

[0056] It can be seen from the results in the above table that the tensile strength and tear strength of the rubber material of the present invention are significantly improved, and at the same time, it has excellent heat aging resistance and excellent comprehensive performance.

[0057] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A heat-resistant aging rubber material for a sealing ring, characterized in that: The invention comprises the following raw materials in parts by weight: 100 parts of nitrile rubber, 15-35 parts of silicone rubber, 20-40 parts of reinforcing agent, 4-10 parts of heat-resistant aging agent, 1-3 parts of vulcanizing agent, 2-6 parts of vulcanization accelerator, 0.5-2 parts of activator and 1-5 parts of plasticizer; the heat-resistant aging agent is a POSS polymer containing hindered amine groups.

2. The heat-resistant aging rubber material for the sealing ring according to claim 1, characterized in that: The POSS polymer containing hindered amine groups is prepared by the following method: a siloxane containing hindered amine groups and a siloxane containing amino groups are subjected to a hydrolysis condensation reaction to obtain a caged silsesquioxane POSS; the caged silsesquioxane POSS is subjected to a condensation reaction with 2-bromoisobutyryl bromide, and then subjected to an atom transfer radical polymerization reaction with 4-cyanostyrene to obtain the POSS polymer containing hindered amine groups.

3. The heat-resistant aging rubber material for sealing ring according to claim 2, characterized in that: The structural formula of the siloxane containing hindered amine groups is as follows: The structural formula of the amino group-containing siloxane is as follows: Preferably, the weight ratio of the hindered amine group-containing siloxane, the amino group-containing siloxane and 4-cyanostyrene is 1:0.1-0.2:1.5-2.

4. The heat-resistant aging rubber material for a sealing ring according to any one of claims 1 to 3, characterized in that: The acrylonitrile content in the nitrile rubber is 25-40%, and the silicone rubber is methyl vinyl silicone rubber.

5. The heat-resistant aging rubber material for a sealing ring according to any one of claims 1 to 4, characterized in that: The reinforcing agent is at least one of high wear-resistant carbon black, semi-reinforcing carbon black, fast extrusion carbon black, calcium bicarbonate, diatomaceous earth or white carbon black.

6. The heat-resistant aging rubber material for a sealing ring according to any one of claims 1 to 5, characterized in that: The vulcanizing agent is at least one of sulfur, vulcanizing agent bis-25 or vulcanizing agent BIBP.

7. The heat-resistant aging rubber material for a sealing ring according to any one of claims 1 to 6, characterized in that: The vulcanization accelerator is at least one of accelerator M, accelerator DM, accelerator TMTD, accelerator CBS or accelerator TETD.

8. The heat-resistant aging rubber material for a sealing ring according to any one of claims 1 to 7, characterized in that: The activator is an oxide and stearic acid, and the oxide is zinc oxide and / or magnesium oxide.

9. The heat-resistant aging rubber material for a sealing ring according to any one of claims 1 to 8, characterized in that: The plasticizer is at least one of dioctyl phthalate, diisononyl phthalate, trioctyl trimellitate or (butoxyethoxyethyl) adipate.

10. A method for preparing the heat-resistant aging rubber material for a sealing ring according to any one of claims 1 to 9, characterized in that: include: The nitrile rubber and the silicone rubber are mixed evenly by weight, and then a reinforcing agent, a heat-resistant aging agent, an activator and a plasticizer are added and mixed evenly. After the rubber is discharged, a vulcanizing agent and a vulcanization accelerator are added and mixed evenly to obtain a final rubber mix; the final rubber mix is ​​vulcanized to obtain a finished product, which is the heat-resistant aging rubber material for the sealing ring.

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