High-temperature-resistant silicone rubber as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of silicone rubber materials, and particularly relates to high-temperature-resistant silicone rubber and a preparation method and application thereof. After the polyimide and the silicone rubber are blended, a compact entanglement structure is formed between a polyimide molecular chain and a silicone rubber molecular chain, and the excellent heat resistance of the polyimide molecular chain can perform effective heat-resistant protection on the silicone rubber molecular chain through the entanglement effect, so that the high-temperature resistance of the silicone rubber is remarkably improved. The polyimide silicone rubber prepared by the invention can resist high temperature of 250 DEG C or above, has good high temperature aging resistance, and is simple to operate and low in manufacturing cost. Therefore, the method has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of silicone rubber materials, and in particular relates to high temperature resistant silicone rubber and a preparation method and application thereof. Background Art

[0002] As a material with excellent mechanical strength, good heat resistance and corrosion resistance, high temperature vulcanized silicone rubber has been widely used in kitchen and bathroom life and maternal and child products, electronic appliances, medical health, wires and cables and insulators, automobiles and rail transportation, industrial processes, aerospace and nuclear power, and is often used to prepare sealing devices under various extreme conditions. With the rapid development of society, the aerospace, high-speed rail ships and semiconductor industries have increasingly stringent requirements on materials, generally requiring temperature resistance to reach above 250°C. Ordinary high temperature vulcanized silicone rubber that can only withstand 200°C can no longer meet industry requirements.

[0003] Although fluororubber can withstand 250℃ and perfluoroether rubber can even withstand over 300℃, they are expensive and bring heavy costs compared to silicone rubber; traditional high temperature resistant silicone rubber is mostly based on methyl vinyl silicone rubber, and the high temperature resistance of silicone rubber is enhanced by adding high temperature resistant additives such as iron oxide and cerium oxide. Although this method can effectively inhibit the cyclization degradation of the main chain of silicone rubber and the oxidation of the side chain by adsorbing free radicals, this type of silicone rubber can only be used for a short time in an environment of 250℃-300℃, and its high temperature aging resistance is still poor. Therefore, the demand for high temperature vulcanized silicone rubber that has good high temperature aging resistance and can withstand 250℃ and above is becoming more and more urgent. Summary of the invention

[0004] In view of the problems of the prior art, the present invention provides a high temperature resistant silicone rubber and a preparation method and use thereof.

[0005] A silicone rubber with high temperature resistance is made of the following raw materials in parts by weight:

[0006] 0.2-0.5 parts of dianhydride monomer,

[0007] 0.1-0.25 parts of diamine monomer,

[0008] 1-5 parts of polar solvent,

[0009] 80-100 parts of silicone rubber

[0010] Vulcanizing agent 0.5-2 parts,

[0011] 30-70 parts of reinforcing agent,

[0012] 2-4 parts of active agent,

[0013] 2-6 parts of heat-resistant agent.

[0014] Preferably, it is made of the following raw materials in parts by weight:

[0015] 0.2 parts of dianhydride monomer,

[0016] 0.1 part of diamine monomer,

[0017] 2 parts of polar solvent,

[0018] 100 parts of silicone rubber

[0019] 1 part of vulcanizing agent,

[0020] 50 parts of reinforcing agent,

[0021] 2 parts of active agent,

[0022] 2 parts of heat-resistant agent.

[0023] Preferably, the dianhydride monomer is selected from at least one of pyromellitic dianhydride and biphenyltetracarboxylic dianhydride;

[0024] And / or, the diamine monomer is selected from at least one of m-phenylenediamine, o-phenylenediamine and diaminodiphenyl ether;

[0025] and / or, the polar solvent is selected from N,N-dimethylformamide;

[0026] And / or, the silicone rubber raw rubber is selected from at least one of methyl silicone rubber and methyl vinyl silicone rubber;

[0027] And / or, the vulcanizing agent is selected from 2,5-dimethyl-2,5-bis-(tert-butylperoxy)hexane;

[0028] and / or, the reinforcing agent is selected from fumed silica;

[0029] and / or, the active agent is selected from zinc oxide;

[0030] And / or, the heat-resistant agent is selected from cerium oxide.

[0031] Preferably, the dianhydride monomer is selected from pyromellitic dianhydride.

[0032] Preferably, the diamine monomer is selected from m-phenylenediamine.

[0033] Preferably, the vulcanized silicone rubber is selected from methyl vinyl silicone rubber.

[0034] The present invention also provides a method for preparing the above-mentioned silicone rubber with high temperature resistance, comprising the following steps:

[0035] Step 1, dissolving a dianhydride monomer and a diamine monomer in a polar solvent for reaction to obtain a solution;

[0036] Step 2, mixing the solution obtained in step 1 with raw silicone rubber, and obtaining a polymer after heat treatment;

[0037] Step 3, kneading the polymer obtained in step 2 with a vulcanizing agent, a reinforcing agent, an activating agent, and a heat-resistant agent to obtain the product.

[0038] Preferably, in step 1, the reaction time is 1-12h;

[0039] And / or, in step 2, the mixing temperature is 20-40°C, and the time is 0.5-1h; the heat treatment condition is a step-by-step heating treatment, i.e., keeping at 110-130°C for 1.5-2.5h, heating from 110-130°C to 140-160°C, keeping at 140-160°C for 1.5-2.5h, heating from 140-160°C to 160-180°C, and keeping at 160-180°C for 1.5-2.5h;

[0040] And / or, in step 3, the kneading time is 2-6 hours.

[0041] The present invention also provides use of the silicone rubber having high temperature resistance in the preparation and / or as a high temperature resistant sealing material.

[0042] The present invention blends polyimide with silicone rubber, and optimizes the selection and dosage of raw materials in the preparation process to improve the high temperature resistance of silicone rubber; the polyimide silicone rubber prepared by the present invention can withstand high temperatures of 250°C and above, has good high temperature aging resistance, is simple to operate, and has low manufacturing costs. Therefore, it has broad application prospects.

[0043] Obviously, according to the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, other various forms of modification, replacement or change may be made.

[0044] The above contents of the present invention are further described in detail below through specific implementation methods in the form of embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above contents of the present invention belong to the scope of the present invention. DETAILED DESCRIPTION

[0045] In the following examples and experimental examples, reagents and raw materials not specifically described are all commercially available products.

[0046] Example 1 Preparation of polyimide silicone rubber

[0047] First, take 0.2g of pyromellitic dianhydride (PMDA) and 0.1g of metaphenylenediamine (MPD) and add them together to 2g of N,N-dimethylformamide (DMF) to react for 1h, then mix it with 100g of methyl vinyl silicone rubber (Nanjing Dongjue Silicone, model 110-2) in a kneader for 30min, take it out and place it in an oven to keep it at 120℃ for 2h, heat it to 150℃ and keep it for 2h, then heat it to 170℃ and keep it for 2h for step-by-step temperature treatment, then take it out and let it cool, place it in a kneader, add 1g of vulcanizing agent bis(25), 50g of fumed silica (Evonik, R972), 2g of zinc oxide, and 2g of cerium oxide, and knead it for 4h to obtain it.

[0048] Example 2 Preparation of polyimide silicone rubber

[0049] First, take 0.5g of pyromellitic dianhydride (PMDA) and 0.25g of metaphenylenediamine (MPD) and add them together to 5g of N,N-dimethylformamide (DMF) to react for 12h, then mix it with 100g of methyl vinyl silicone rubber in a kneader for 30min, then take it out and place it in an oven to keep it at 120℃ for 2h, heat it to 150℃ and keep it for 2h, then heat it to 170℃ and keep it for 2h for step-by-step temperature treatment, then take it out and let it cool, place it in a kneader, add 1g of vulcanizing agent bis(25), 50g of fumed silica, 2g of zinc oxide, and 2g of cerium oxide, and knead it for 4h to obtain it.

[0050] Example 3 Preparation of polyimide silicone rubber

[0051] First, take 0.3g of pyromellitic dianhydride (PMDA) and 0.1g of metaphenylenediamine (MPD) and add them together to 2g of N,N-dimethylformamide (DMF) to react for 12h, then mix it with 100g of methyl vinyl silicone rubber in a kneader for 30min, then take it out and place it in an oven to keep it at 120℃ for 2h, heat it to 150℃ and keep it for 2h, then heat it to 170℃ and keep it for 2h for step-by-step temperature treatment, then take it out and let it cool, place it in a kneader, add 1g of vulcanizing agent bis(25), 50g of fumed silica, 2g of zinc oxide, and 2g of cerium oxide, and knead it for 4h to obtain it.

[0052] Example 4 Preparation of polyimide silicone rubber

[0053] First, take 0.3g of pyromellitic dianhydride (PMDA) and 0.1g of o-phenylenediamine (OPD) and add them together to 1g of N,N-dimethylformamide (DMF) to react for 12h, then mix it with 100g of methyl vinyl silicone rubber in a kneader for 30min, then take it out and place it in an oven to keep it at 120℃ for 2h, heat it to 150℃ and keep it for 2h, then heat it to 170℃ and keep it for 2h for step-by-step temperature treatment, then take it out and let it cool, place it in a kneader, add 1g of vulcanizing agent bis(25), 50g of fumed silica, 2g of zinc oxide, and 2g of cerium oxide, and knead it for 4h to obtain it.

[0054] Example 5 Preparation of polyimide silicone rubber

[0055] First, take 0.3g of pyromellitic dianhydride (PMDA) and 0.1g of o-phenylenediamine (OPD) and add them together to 2g of N,N-dimethylformamide (DMF) to react for 12h, then mix it with 100g of methyl vinyl silicone rubber in a kneader for 30min, then take it out and place it in an oven to keep it at 120℃ for 2h, heat it to 150℃ and keep it for 2h, then heat it to 170℃ and keep it for 2h for step-by-step temperature treatment, then take it out and let it cool, place it in a kneader, add 1g of vulcanizing agent bis(25), 50g of fumed silica, 2g of zinc oxide, and 2g of cerium oxide, and knead it for 4h to obtain it.

[0056] Example 6 Preparation of polyimide silicone rubber

[0057] First, take 0.3g of biphenyltetracarboxylic dianhydride (BPDA) and 0.1g of diaminodiphenyl ether (ODA) and add them together to 1g of N,N-dimethylformamide (DMF) to react for 12h, then mix it with 100g of methyl vinyl silicone rubber in a kneader for 30min, then take it out and place it in an oven to keep it at 120℃ for 2h, heat it to 150℃ and keep it for 2h, then heat it to 170℃ and keep it for 2h for step-by-step temperature treatment, then take it out and wait for it to cool, place it in a kneader, add 1g of vulcanizing agent dipentadiene, 50g of fumed silica, 2g of zinc oxide, and 2g of cerium oxide, and knead it for 4h to obtain it.

[0058] The differences in the formulations of the polyimide silicone rubber of Examples 1-6 are summarized as follows (Table 1).

[0059] Table 1

[0060]

[0061]

[0062] The following is the preparation method of the control sample.

[0063] Comparative Example 1 Silicone rubber without adding polyimide

[0064] Add 100 g of methyl vinyl silicone rubber, 1 g of vulcanizing agent bis(250), 50 g of fumed silica, 2 g of zinc oxide and 2 g of cerium oxide into a kneader in sequence and knead for 4 hours to obtain the product.

[0065] The technical solution of the present invention is further illustrated by experiments below.

[0066] Experimental Example 1 High temperature resistance of polyimide silicone rubber

[0067] 1. Experimental Methods

[0068] The silicone rubber prepared in the above Examples 1 to 6 and Comparative Example 1 was placed in an oven at 250° C. for aging for 7 days, and the hardness change rate, elongation at break change rate and strength change rate of the silicone rubber were calculated.

[0069] Calculation method of hardness change rate:

[0070] Hardness change rate (%) = (hardness before aging - hardness after aging) / hardness before aging.

[0071] Calculation method of elongation at break change rate:

[0072] Change rate of elongation at break (%) = (elongation at break before aging - elongation at break after aging) / elongation at break before aging.

[0073] Calculation method of intensity change rate:

[0074] Strength change rate (%) = (strength before aging - strength after aging) / strength before aging.

[0075] 2. Experimental Results

[0076] Examples 1 to 6, the data of the silicone rubber prepared in Comparative Example 1 before and after aging are shown in Tables 2 and 3, respectively. After the data is processed (Table 4), it can be found that the silicone rubber not treated with polyimide (Comparative Example 1) has a significantly increased hardness change rate (positive value), and a significantly reduced elongation at break and strength change rate (negative value) compared with Examples 1-6, indicating that after the silicone rubber prepared in Comparative Example 1 is aged at high temperature (250°C), its side chain is severely oxidized, the hardness increases sharply, the flexibility and elasticity decrease, the load-bearing capacity decreases, and the performance decays greatly. The polyimide silicone rubber prepared by the present invention has relatively stable performance under high temperature conditions.

[0077] Among Examples 1-6, Example 1 has the smallest hardness change rate, slightly reduced elongation at break change rate and strength change rate, the most stable performance under high temperature conditions, and the best high temperature resistance.

[0078] Table 2 Silicone rubber data before aging

[0079]

[0080] Table 3 Data of silicone rubber after aging

[0081]

[0082] Table 4

[0083]

[0084]

[0085] In summary, the present invention blends polyimide with silicone rubber to improve the high temperature resistance of silicone rubber; the polyimide silicone rubber prepared by the present invention can withstand high temperatures of 250°C and above, has good high temperature aging resistance, and is simple to operate and has low manufacturing costs. Therefore, it has broad application prospects.

Claims

1. A silicone rubber having high temperature resistance, characterized in that: It is made of the following raw materials in parts by weight: 0.2-0.5 parts of dianhydride monomer, 0.1-0.25 parts of diamine monomer, 1-5 parts of polar solvent, 80-100 parts of silicone rubber Vulcanizing agent 0.5-2 parts, 30-70 parts of reinforcing agent, 2-4 parts of active agent, 2-6 parts of heat-resistant agent.

2. The high temperature resistant silicone rubber according to claim 1, characterized in that: It is made of the following raw materials in parts by weight: 0.2 parts of dianhydride monomer, 0.1 part of diamine monomer, 2 parts of polar solvent, 100 parts of silicone rubber 1 part of vulcanizing agent, 50 parts of reinforcing agent, 2 parts of active agent, 2 parts of heat-resistant agent.

3. The high temperature resistant silicone rubber according to claim 1 or 2, characterized in that: The dianhydride monomer is selected from at least one of pyromellitic dianhydride and biphenyltetracarboxylic dianhydride; And / or, the diamine monomer is selected from at least one of m-phenylenediamine, o-phenylenediamine and diaminodiphenyl ether; and / or, the polar solvent is selected from N,N-dimethylformamide; And / or, the silicone rubber raw rubber is selected from at least one of methyl silicone rubber and methyl vinyl silicone rubber; And / or, the vulcanizing agent is selected from 2,5-dimethyl-2,5-bis-(tert-butylperoxy)hexane; and / or, the reinforcing agent is selected from fumed silica; and / or, the active agent is selected from zinc oxide; And / or, the heat-resistant agent is selected from cerium oxide.

4. The high temperature resistant silicone rubber according to claim 3, characterized in that: The dianhydride monomer is selected from pyromellitic dianhydride.

5. The high temperature resistant silicone rubber according to claim 3, characterized in that: The diamine monomer is selected from meta-phenylenediamine.

6. The high temperature resistant silicone rubber according to claim 3, characterized in that: The vulcanized silicone rubber is selected from methyl vinyl silicone rubber.

7. The method for preparing the silicone rubber with high temperature resistance according to any one of claims 1 to 6, characterized in that: The steps include: Step 1, dissolving a dianhydride monomer and a diamine monomer in a polar solvent for reaction to obtain a solution; Step 2, mixing the solution obtained in step 1 with raw silicone rubber, and obtaining a polymer after heat treatment; Step 3, kneading the polymer obtained in step 2 with a vulcanizing agent, a reinforcing agent, an activating agent, and a heat-resistant agent to obtain the product.

8. The preparation method according to claim 7, characterized in that: In step 1, the reaction time is 1-12h; And / or, in step 2, the mixing temperature is 20-40°C, and the time is 0.5-1h; the heat treatment condition is a step-by-step heating treatment, i.e., keeping warm at 110-130°C for 1.5-2.5h, heating from 110-130°C to 140-160°C, keeping warm at 140-160°C for 1.5-2.5h, heating from 140-160°C to 160-180°C, and keeping warm at 160-180°C for 1.5-2.5h; And / or, in step 3, the kneading time is 2-6 hours.

9. Use of the high temperature resistant silicone rubber according to any one of claims 1 to 6 in the preparation and / or as a high temperature resistant sealing material.

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