Nuclear low-sulfur halogen-free radiation-resistant ethylene propylene diene monomer rubber and preparation method thereof

Abstract

The invention discloses a nuclear low-sulfur, halogen-free and radiation-resistant ethylene propylene diene monomer and a preparation method thereof, and relates to the technical field of nuclear rubber, ethylene and propylene are used as basic units and are mixed according to a ratio of 1: 2, a third monomer is non-conjugated diene free of sulfur and halogen, a low-sulfur or sulfur-free vulcanization system is selected, and a second monomer is a low-sulfur or sulfur-free vulcanization system; according to the low-sulfur, halogen-free and radiation-resistant ethylene propylene diene monomer rubber, the influence of six elements on the product performance is avoided, the halogen-free additive and filler are selected, harmful substances of the ethylene propylene diene monomer rubber can be effectively reduced through the low-sulfur and halogen-free characteristics, the safety and environmental protection property of the product are improved, and the low-sulfur, halogen-free and radiation-resistant ethylene propylene diene monomer rubber can keep stable performance under extreme conditions and is suitable for industrial production. And the ethylene propylene diene monomer has better processability, and is processed and formed in various modes such as extrusion, injection molding or calendaring, so that the production cost is reduced, and the production efficiency is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear rubber, in particular to a nuclear low-sulfur, halogen-free, radiation-resistant ethylene propylene diene monomer rubber and a preparation method thereof. Background Art

[0002] Low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use is a rubber material with special performance requirements and is mainly used in fields such as the nuclear industry that require high safety standards and extreme conditions. Due to the special performance requirements of low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use, its production and use need to strictly comply with relevant safety specifications and standards. During use, regular inspection and maintenance are also required to ensure the stability and safety of its performance. Therefore, the present invention proposes a low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use and a preparation method thereof. Summary of the invention

[0003] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use, wherein ethylene and propylene are used as basic units and mixed in a ratio of 1:2, the third monomer is a non-conjugated diene that does not contain sulfur and halogen, a low-sulfur or sulfur-free vulcanization system is selected to avoid the influence of the six elements on product performance, halogen-free additives and fillers are selected, such as high-wear-resistant carbon black, stearic acid, zinc oxide and magnesium oxide, and their content is strictly controlled to meet the requirements of low sulfur and halogen-free.

[0004] Preferably, under the action of an initiator, ethylene, propylene and a third monomer are added into a polymerization kettle in a ratio of 1:2:1 to carry out copolymerization to generate EPDM rubber.

[0005] Preferably, the polymerization reaction needs to be carried out under certain temperature and pressure conditions, usually the reaction temperature is 50-80° C. and the pressure is 1-3 MPa.

[0006] Preferably, the unreacted monomers and low molecular weight substances in the rubber are removed by vacuum degassing or steam purging, and the rubber particles are dried to remove moisture and other impurities therein.

[0007] Preferably, the product is packaged after passing the test, using polyethylene plastic bags or paper-plastic composite bags, with a net weight of 25kg or 50kg per bag.

[0008] A method for preparing low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use comprises the following steps:

[0009] S1: Raw material selection, ethylene and propylene, non-conjugated dienes, vulcanization system and additives and fillers

[0010] S2: Formula design, according to the specific performance requirements of the product, such as radiation resistance, aging resistance and physical strength, adjust the ratio of ethylene, propylene and the third monomer, as well as the type and amount of the vulcanization system and additives;

[0011] S3: production process, post-treatment, including degassing, extrusion granulation and drying steps to remove unreacted monomers and low molecular volatiles and obtain rubber particles that meet the requirements;

[0012] S4: Radiation resistance modification, improving the radiation resistance of EPDM rubber by physical or chemical methods;

[0013] S5: Quality inspection and packaging, quality inspection of the produced low-sulfur, halogen-free, radiation-resistant EPDM rubber, including the detection of Mooney viscosity, molecular weight distribution, vulcanization characteristics and other indicators.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The invention can effectively reduce harmful substances in EPDM rubber by virtue of its low-sulfur and halogen-free characteristics, thereby improving the safety and environmental friendliness of the product. The low-sulfur, halogen-free and radiation-resistant EPDM rubber can maintain stable performance under extreme conditions and extend its service life. The EPDM rubber has good processing performance and can be processed and formed by various methods such as extrusion, injection molding or calendering, thereby helping to reduce production costs and further improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flow chart for preparing the low-sulfur, halogen-free, radiation-resistant EPDM rubber. DETAILED DESCRIPTION

[0017] See also Figure 1 The present invention provides a technical solution: a low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use

[0018] Embodiment 1:

[0019] Ethylene and propylene are used as the basic units and are mixed in a ratio of 1:2. The third monomer is a non-conjugated diene that does not contain sulfur and halogen. A low-sulfur or sulfur-free vulcanization system is selected to avoid the influence of the six elements on product performance. Halogen-free additives and fillers are selected, such as high-wear-resistant carbon black, stearic acid, zinc oxide and magnesium oxide, and their content is strictly controlled to meet the requirements of low sulfur and halogen-free.

[0020] Under the action of the initiator, ethylene, propylene and the third monomer are added to the polymerization kettle in a ratio of 1:2:1 to carry out copolymerization to produce EPDM rubber. The polymerization reaction needs to be carried out under certain temperature and pressure conditions. Usually the reaction temperature is 50-80°C and the pressure is 1-3MPa. The unreacted monomers and low molecular weight substances in the rubber are removed by vacuum degassing or steam blowing. The rubber particles are dried to remove moisture and other impurities. After passing the inspection, they are packaged in polyethylene plastic bags or paper-plastic composite bags. The net weight of each bag is 25kg or 50kg.

[0021] Embodiment 2:

[0022] Ethylene and propylene are used as the basic units and are mixed in a ratio of 1:2. The third monomer is a non-conjugated diene that does not contain sulfur and halogen. A low-sulfur or sulfur-free vulcanization system is selected to avoid the influence of the six elements on product performance. Halogen-free additives and fillers are selected, such as high-wear-resistant carbon black, stearic acid, zinc oxide and magnesium oxide, and their content is strictly controlled to meet the requirements of low sulfur and halogen-free.

[0023] Under the action of the initiator, ethylene, propylene and the third monomer are added into the polymerization kettle in a ratio of 2:1:1 to carry out copolymerization to produce EPDM rubber. The polymerization reaction needs to be carried out under certain temperature and pressure conditions. Usually the reaction temperature is 60-80℃ and the pressure is 2-3MPa. The unreacted monomers and low molecular weight substances in the rubber are removed by vacuum degassing or steam blowing. The rubber particles are dried to remove moisture and other impurities. After passing the inspection, they are packaged in polyethylene plastic bags or paper-plastic composite bags. The net weight of each bag is 25kg or 50kg.

[0024] A method for preparing low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use comprises the following steps:

[0025] S1: Raw material selection, ethylene and propylene, non-conjugated dienes, vulcanization system and additives and fillers

[0026] S2: Formula design, according to the specific performance requirements of the product, such as radiation resistance, aging resistance and physical strength, adjust the ratio of ethylene, propylene and the third monomer, as well as the type and amount of the vulcanization system and additives;

[0027] S3: production process, post-treatment, including degassing, extrusion granulation and drying steps to remove unreacted monomers and low molecular volatiles and obtain rubber particles that meet the requirements;

[0028] S4: Radiation resistance modification, improving the radiation resistance of EPDM rubber by physical or chemical methods;

[0029] S5: Quality inspection and packaging, quality inspection of the produced low-sulfur, halogen-free, radiation-resistant EPDM rubber, including the detection of Mooney viscosity, molecular weight distribution, vulcanization characteristics and other indicators.

Claims

1. A low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use, characterized in that: The ethylene and propylene are used as basic units and are mixed in a ratio of 1:

2. The third monomer is a non-conjugated diene that does not contain sulfur and halogen. A low-sulfur or sulfur-free vulcanization system is selected to avoid the influence of the six elements on product performance. Halogen-free additives and fillers are selected, such as high-wear-resistant carbon black, stearic acid, zinc oxide and magnesium oxide, and their content is strictly controlled to meet the requirements of low sulfur and halogen-free.

2. The low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use according to claim 1, characterized in that: Under the action of the initiator, ethylene, propylene and the third monomer are added into a polymerization kettle in a ratio of 1:2:1 to carry out copolymerization reaction to generate EPDM rubber.

3. The low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use according to claim 1, characterized in that: The polymerization reaction needs to be carried out under certain temperature and pressure conditions, usually the reaction temperature is 50-80° C. and the pressure is 1-3 MPa.

4. The low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use according to claim 1, characterized in that: The unreacted monomers and low molecular weight substances in the rubber are removed by vacuum degassing or steam blowing, and the rubber particles are dried to remove moisture and other impurities therein.

5. The low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use according to claim 1, characterized in that: After the test is passed, the product is packaged in polyethylene plastic bags or paper-plastic composite bags, with a net weight of 25kg or 50kg per bag.

6. A method for preparing a low-sulfur, halogen-free, radiation-resistant EPDM rubber for nuclear use according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: Raw material selection, ethylene and propylene, non-conjugated dienes, vulcanization system and additives and fillers S2: Formula design, according to the specific performance requirements of the product, such as radiation resistance, aging resistance and physical strength, adjust the ratio of ethylene, propylene and the third monomer, as well as the type and amount of the vulcanization system and additives; S3: production process, post-treatment, including degassing, extrusion granulation and drying steps to remove unreacted monomers and low molecular volatiles and obtain rubber particles that meet the requirements; S4: Radiation resistance modification, improving the radiation resistance of EPDM rubber by physical or chemical methods; S5: Quality inspection and packaging, quality inspection of the produced low-sulfur, halogen-free, radiation-resistant EPDM rubber, including the detection of Mooney viscosity, molecular weight distribution, vulcanization characteristics and other indicators.

Images