Ethylene propylene diene monomer-based sealing material for nuclear power equipment and preparation method of ethylene propylene diene monomer-based sealing material

Abstract

The invention belongs to the technical field of special rubber, relates to an ethylene propylene diene monomer-based sealing material for nuclear power equipment and a preparation method thereof, and provides an ethylene propylene diene monomer-based sealing material for nuclear power equipment, which is composed of ethylene propylene diene monomer, a first auxiliary agent, a second auxiliary agent and a third auxiliary agent. The first auxiliary agent is conventionally used for rubber molding; the second auxiliary agent is a tackifying auxiliary agent and is used for realizing effective bonding of the non-polar saturated rubber and the fabric, so that the fabric is effectively prevented from being subjected to internal damage caused by stress concentration at high temperature and high pressure, and the service life of the fabric is not influenced; and the third auxiliary agent is an anti-aging auxiliary agent and is used for improving the performance of the EPDM rubber-based sealing material and meeting the technical requirements under accident working conditions. The second auxiliary agent and the third auxiliary agent cooperate with each other and do not conflict with each other, so that the synergistic interaction effect among the auxiliary agents of the EPDM-based sealing material is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of special rubbers and relates to an EPDM rubber-based sealing material for nuclear power equipment and a preparation method thereof. Background Art

[0002] The pneumatic diaphragm pump is a positive displacement reciprocating pump driven by compressed gas. The pneumatic diaphragm pump consists of two major parts: the air flow structure and the liquid flow structure, which are completely isolated by the diaphragms on both sides. The air source pressure only needs to be greater than two kilograms per square centimeter to work. Under the alternating action of high and low pressure gases on both sides, the connecting rod shaft drives the diaphragms on both sides to move left and right, so that the air pressure in the volume chambers on both sides changes alternately, thereby realizing the continuous suction and discharge of liquid. In nuclear power units, pneumatic diaphragm pumps are used for radioactive monitoring sampling. Due to the special application environment of nuclear power units, higher requirements are placed on the sealing materials of pneumatic diaphragm pumps, which are nuclear power equipment. Summary of the invention

[0003] In order to solve the above problems, the purpose of the present invention is to provide an EPDM rubber-based sealing material that meets the technical requirements of nuclear power technology and meets the technical requirements under accident conditions of nuclear power equipment, and solves the technical problems of poor adhesion between EPDM rubber-based sealing materials and fabrics and weak aging resistance.

[0004] Based on the above purpose, the present invention provides an EPDM rubber-based sealing material for nuclear power equipment and a preparation method thereof to meet the needs in the art.

[0005] On the other hand, the present invention relates to an EPDM rubber-based sealing material for nuclear power equipment, which is composed of 100 parts of EPDM rubber, 100-130 parts of a first auxiliary agent, 12-20 parts of a second auxiliary agent and 4-9 parts of a third auxiliary agent in parts by mass; In parts by mass, the first auxiliary agent is composed of 8 to 12 parts of activator, 1 to 3 parts of antioxidant, 4 to 6 parts of wear-resistant agent, 28 to 32 parts of high wear-resistant carbon black, 45 to 55 parts of radiation-resistant anthracene oil carbon black, 4 to 6 parts of oligomeric ester, 8 to 12 parts of plasticizer, 4 to 6 parts of vulcanizer and 1 to 3 parts of accelerator; In parts by mass, the second auxiliary agent is composed of 5 to 10 parts of carboxymethyl cellulose, 1 to 6 parts of alkyl dimethyl amine oxide, and 1 to 5 parts of tannic acid; The third auxiliary agent is composed of 5-10 parts of fumed silica, 12-20 parts of tetraethyl orthosilicate, and 4-6 parts of silane coupling agent A-171.

[0006] Furthermore, in the EPDM-based sealing material for nuclear power equipment provided by the present invention, the activator is zinc oxide, the antioxidant is selected from antioxidant RD, the wear-resistant agent is polyphenyl ester, the high wear-resistant carbon black is selected from one of carbon black N220, carbon black N550, and carbon black N660, the radiation-resistant anthracene oil carbon black is carbon black N375, the plasticizer is paraffin oil, the vulcanizer is vulcanizer DCP, and the accelerator is accelerator TAIC.

[0007] Furthermore, in the EPDM rubber-based sealing material for nuclear power equipment provided by the present invention, the fumed silica is hydrophobic fumed silica.

[0008] On the other hand, the present invention relates to a method for preparing an EPDM rubber-based sealing material for nuclear power equipment, wherein the method comprises: blending EPDM rubber, high wear-resistant carbon black and radiation-resistant anthracene oil carbon black, thinning, and then adding the second auxiliary agent in multiple batches, and rolling the mixture obliquely 7 to 8 times after adding the second auxiliary agent each time to obtain a masterbatch; After the masterbatch is left to stand for 20 to 30 hours, it is thinned and passed 40 to 60 times to obtain a secondary masterbatch; The secondary masterbatch is left to stand for 20 to 30 hours to obtain a film with a thickness of 1 mm. After drying, an activator, an antioxidant, an anti-wear agent, a polyester, a plasticizer, a vulcanizer, a accelerator and the third auxiliary agent are added and mixed to obtain the shaft seal rubber for the nuclear power main pump shaft.

[0009] Furthermore, in the method for preparing EPDM rubber-based sealing materials for nuclear power equipment provided by the present invention, the multiple batches are 3 to 8 times.

[0010] On the other hand, the present invention relates to a method for preparing a rubber sealing ring, which comprises: an EPDM rubber-based sealing material and a fiber fabric for nuclear power equipment; The second auxiliary agent is evenly applied on the surface of the fiber fabric, and after drying at room temperature, EPDM rubber-based sealing materials for nuclear power equipment are simultaneously pasted on the upper and lower surfaces of the fiber fabric, and the airbag is heated and pressurized.

[0011] Furthermore, in the method for preparing the rubber sealing ring provided by the present invention, the fiber fabric is composed of at least two of carbon fiber, aramid fiber, and basalt fiber.

[0012] Furthermore, in the method for preparing the rubber sealing ring provided by the present invention, the mass proportion of any fiber in the fiber fabric is not less than 30%.

[0013] Furthermore, in the method for preparing the rubber sealing ring provided by the present invention, the second auxiliary agent is evenly applied on the surface of the fiber fabric, and the amount of the second auxiliary agent is 0.5-0.8 kg / m 2 .

[0014] On the other hand, the present invention relates to a rubber sealing ring, which is prepared by the above-mentioned preparation method of the rubber sealing ring.

[0015] Through the above technical solution, the technical solution provided by the present invention has at least the following beneficial effects or advantages: (1) The present invention provides an EPDM rubber-based sealing material for nuclear power equipment, which is composed of EPDM rubber, a first additive, a second additive and a third additive. The first additive is conventionally used for rubber molding; the second additive is a viscosity-increasing additive used to achieve effective bonding between non-polar saturated rubber and fabric, effectively protecting the fabric from internal damage caused by stress concentration under high temperature and high pressure, which affects its service life; the third additive is an anti-aging additive used to improve the performance of the EPDM rubber-based sealing material to meet the technical requirements under accident conditions.

[0016] (2) The EPDM rubber-based sealing material for nuclear power equipment provided by the present invention comprises a third auxiliary agent made of hydrophobic fumed silica, tetraethyl orthosilicate and a silane coupling agent. Due to the methyl groups on the surface of the hydrophobic fumed silica and the silicon ions increased by the tetraethyl orthosilicate, the methyl groups on the surface of the hydrophobic fumed silica and the silicon ions increased by the tetraethyl orthosilicate interact well with the second auxiliary agent under the action of the silane coupling agent to form a mutually adherent structure, so that the original function of the second auxiliary agent is not affected and a synergistic effect is exhibited.

[0017] (3) The present invention also provides a method for preparing a rubber sealing ring, which uses a fiber fabric composed of at least two of the following: carbon fiber, aramid fiber, and basalt fiber. The fiber fabric is composed of the difference in linear density of the three fibers. The rubber sealing member prepared by combining the fiber fabric with an EPDM rubber-based sealing material exhibits more excellent performance in an aging test. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments, but the embodiments are not intended to limit the present invention.

[0019] The experimental methods and detection methods described in the following embodiments are conventional methods unless otherwise specified; the test supplies and raw materials are all commercially available unless otherwise specified. Example

[0020] This embodiment provides a process for preparing a rubber sealing ring.

[0021] EPDM rubber and paraffin oil (aromatic content < 0.5 wt%) were purchased from Guangzhou Liben Rubber Raw Materials Trading Co., Ltd., and hydrophobic fumed silica (HB-620) was purchased from Hubei Huifu Nanomaterials Co., Ltd.

[0022] The preparation process of EPDM rubber-based sealing materials is as follows: Step 1: EPDM rubber, high wear-resistant carbon black and radiation-resistant anthracene oil carbon black are mixed in an open rubber mixer for 20 minutes, and the roller distance is adjusted to 1 mm and passed three times; the roller diameter of the open rubber mixer is 400 mm; Step 2: Adjust the roller distance to 3 mm, add the second additive into the open rubber mixer after the thin pass in step 1 in 3 times under the condition of roller temperature of 100°C, and roll it obliquely 8 times after each addition to obtain a masterbatch; Step 3: the masterbatch obtained in step 2 is left standing for 20 hours to obtain a masterbatch after standing; Step 4: When the roller temperature of the open rubber mixer is 90° C. and the roller distance is 0.5 mm, the masterbatch prepared in step 3 is passed through the open rubber mixer for 60 times to obtain a secondary masterbatch; Step 5: The secondary masterbatch prepared in step 4 is placed for 20 hours to produce a film having a thickness of 1 mm. The film is placed in a drying oven at 150° C. and dried for 20 hours to obtain a dried film; Step six: add the dried film obtained in step five, an activator, an antioxidant, an anti-wear agent, a polyester, a plasticizer, a vulcanizer, an accelerator and a third auxiliary agent and mix them to obtain a shaft sealing rubber; the mixing temperature is 80° C. and the mixing time is 2 hours.

[0023] The preparation process of the fiber fabric is as follows: at least two of the carbon fiber, aramid fiber and basalt fiber are mixed in proportion and then dispersed to obtain the fiber fabric.

[0024] Preparation of rubber sealing ring: The second auxiliary agent is evenly applied on the surface of the fiber fabric, and after drying at room temperature, EPDM rubber-based sealing material for nuclear power equipment is simultaneously pasted on the upper and lower surfaces of the fiber fabric, and the airbag is heated and pressed to obtain the rubber sealing ring. Example

[0025] This example provides a rubber sealing ring formula and performance test results, and the preparation process refers to Example 1.

[0026] In parts by mass, the components are as follows: Test group 1#: 100 parts of EPDM rubber, 100 parts of the first additive, 12 parts of the second additive and 4 parts of the third additive; the first additive is composed of 8 parts of zinc oxide, 1 part of antioxidant RD, 4 parts of polyphenyl ester, 28 parts of carbon black N220, 45 parts of carbon black N375, 4 parts of oligomeric ester, 8 parts of paraffin oil, 4 parts of vulcanizing agent DCP and 1 part of accelerator TAIC; the second additive is composed of 5 parts of carboxymethyl cellulose, 1 part of alkyl dimethyl amine oxide and 1 part of tannic acid; the third additive is composed of 5 parts of hydrophobic fumed silica, 12 parts of tetraethyl orthosilicate and 4 parts of silane coupling agent A-171; the fiber fabric is composed of 1 part of carbon fiber and 1 part of basalt fiber; the second additive is evenly applied on the surface of the fiber fabric, and the amount of the second additive is 0.5kg / m 2 .

[0027] Test group 2#: 100 parts of EPDM rubber, 120 parts of the first additive, 16 parts of the second additive and 6 parts of the third additive; the first additive is composed of 10 parts of zinc oxide, 2 parts of antioxidant RD, 5 parts of polyphenyl ester, 30 parts of carbon black N550, 50 parts of carbon black N375, 5 parts of oligomeric ester, 10 parts of paraffin oil, 5 parts of vulcanizing agent DCP and 2 parts of accelerator TAIC; the second additive is composed of 7 parts of carboxymethyl cellulose, 3 parts of alkyl dimethyl amine oxide and 2 parts of tannic acid; the third additive is composed of 7 parts of hydrophobic fumed silica, 16 parts of tetraethyl orthosilicate and 5 parts of silane coupling agent A-171; the fiber fabric is composed of 3 parts of carbon fiber, 3 parts of aramid fiber and 4 parts of basalt fiber; the second additive is evenly applied on the surface of the fiber fabric, and the dosage of the second additive is 0.6kg / m 2 .

[0028] Test group 3#: 100 parts of EPDM rubber, 130 parts of the first additive, 20 parts of the second additive and 9 parts of the third additive; the first additive is composed of 12 parts of zinc oxide, 3 parts of antioxidant RD, 6 parts of polyphenyl ester, 32 parts of carbon black N550, 55 parts of carbon black N660, 6 parts of oligoester, 12 parts of paraffin oil, 6 parts of vulcanizing agent DCP and 3 parts of accelerator TAIC; the second additive is composed of 10 parts of carboxymethyl cellulose, 6 parts of alkyl dimethyl amine oxide and 5 parts of tannic acid; the third additive is composed of 10 parts of hydrophobic fumed silica, 20 parts of tetraethyl orthosilicate and 6 parts of silane coupling agent A-171; the fiber fabric is composed of 7 parts of aramid fiber and 3 parts of basalt fiber; the second additive is evenly applied on the surface of the fiber fabric, and the dosage of the second additive is 0.8kg / m 2 .

[0029] The EPDM rubber-based sealing materials and rubber sealing rings provided by test group 1# to test group 3# were tested to make diaphragm materials and O-ring materials respectively.

[0030] (1) Basic performance research: Combined with the performance of imported parts materials, multiple indicators such as hardness, tensile strength, elongation at break, compression set, heat aging resistance, etc. are evaluated simultaneously, formulas are designed and trial-produced, and system performance is tested, screened, optimized, and determined; (2) Study on heat aging resistance: Combined with the product storage life (10 years) and service life (2 years for diaphragms and 2 years for O-rings), according to the accelerated heat aging formula of "Identification of Nuclear Power Plant Dynamic Mechanical Equipment Part 3 Identification of Non-metallic Items" NB / T20036.3-2011, the storage life is 25°C and the service life is 60°C. The accelerated heat aging test is carried out on the rubber material during the service life. The aging conditions of the diaphragm rubber material and the O-ring rubber material should be 150°C × 56h. The hardness change, tensile strength change, elongation change and compression permanent deformation (A type 25% compression rate) before and after aging are tested to further determine the material; (3) Study on radiation aging resistance: At an irradiation dose rate of 200 Gy / h and a cumulative dose of 1×10 5 Gy; irradiate rubber materials, compare the hardness, tensile strength, elongation at break, and compression set of samples before and after irradiation to obtain the attenuation of material properties with irradiation dose, evaluate the radiation resistance of materials, and conduct technical comparison with imported spare parts to provide data support for localization; (4) LOCA resistance test study: Boric acid 1.5%; sodium hydroxide 0.6%; 20°C, pH 9.26; spray rate 1.02×10 -4 m 3 / s / m2 Time Phase 6 begins and lasts for 14 days.

[0031] (5) Simulated operating condition endurance test (comparison after 14-day fatigue test of finished product): Continuous operation (fatigue) for 14 days in the sampling pump equipment of the nuclear power unit, simulating the actual on-site operating conditions.

[0032] After 14 days of fatigue operation test simulating actual on-site working conditions, there were no abnormalities or damage in the appearance of the diaphragm rubber material and the O-ring rubber material.

[0033] The EPDM rubber-based sealing material and rubber sealing ring provided by the present invention have excellent heat aging resistance, radiation resistance and LOCA resistance capabilities, and meet the sealing requirements under DBA working conditions and SA working conditions.

[0034] This embodiment also sets up control group 1# to control group 3#, which are as follows: Control group 1#: Same as test group 2#, except that the fiber fabric is made of carbon fiber; Control group 2#: Same as test group 2#, except that the third auxiliary agent is not included; Control group 3#: Same as control group 2#, except that the second auxiliary agent, carboxymethyl cellulose, is replaced by xanthan gum. The obtained O-ring material is tested for radiation resistance, and the test method is the same as above.

[0035] Although the fabric composed of a single fiber in the control group 1# can also meet the index requirements, its performance after radiation is lower than that of the test group; the control group 2# does not contain the third additive, and its performance cannot meet the index requirements of nuclear power equipment; when the carboxymethyl cellulose in the second additive of the control group 3# is replaced with xanthan gum, the function of the second additive conflicts with the third additive, which will lead to a decrease in performance. After 14 days of fatigue operation test simulating actual working conditions on site, abnormal phenomena such as particles and cracks appeared on the surface of the control group 2# and the control group 3#.

[0036] As described above, the present invention can be well implemented. The above embodiments are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various changes and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the present invention.

Claims

1. An EPDM rubber-based sealing material for nuclear power equipment, characterized in that: In parts by mass, the EPDM rubber-based sealing material is composed of 100 parts of EPDM rubber, 100-130 parts of a first additive, 12-20 parts of a second additive, and 4-9 parts of a third additive; In parts by mass, the first auxiliary agent is composed of 8 to 12 parts of activator, 1 to 3 parts of antioxidant, 4 to 6 parts of wear-resistant agent, 28 to 32 parts of high wear-resistant carbon black, 45 to 55 parts of radiation-resistant anthracene oil carbon black, 4 to 6 parts of oligomeric ester, 8 to 12 parts of plasticizer, 4 to 6 parts of vulcanizer and 1 to 3 parts of accelerator; In parts by mass, the second auxiliary agent is composed of 5 to 10 parts of carboxymethyl cellulose, 1 to 6 parts of alkyl dimethyl amine oxide, and 1 to 5 parts of tannic acid; The third auxiliary agent is composed of 5-10 parts of fumed silica, 12-20 parts of tetraethyl orthosilicate, and 4-6 parts of silane coupling agent A-171.

2. The EPDM rubber-based sealing material for nuclear power equipment according to claim 1, characterized in that: The activator is zinc oxide, the antioxidant is selected from antioxidant RD, the wear-resistant agent is polyphenyl ester, the high wear-resistant carbon black is selected from one of carbon black N220, carbon black N550, and carbon black N660, the radiation-resistant anthracene oil carbon black is carbon black N375, the plasticizer is paraffin oil, the vulcanizer is vulcanizer DCP, and the accelerator is accelerator TAIC.

3. The EPDM rubber-based sealing material for nuclear power equipment according to claim 1, characterized in that: The fumed silica is hydrophobic fumed silica.

4. A method for preparing an EPDM-based sealing material for nuclear power equipment, characterized in that: The preparation of the EPDM rubber-based sealing material for nuclear power equipment according to claim 1 comprises: blending EPDM rubber, high wear-resistant carbon black and radiation-resistant anthracene oil carbon black, thinning, and then adding the second auxiliary agent in multiple batches, and rolling the second auxiliary agent obliquely 7 to 8 times after each addition to obtain a masterbatch; After the masterbatch is left to stand for 20 to 30 hours, it is thinned and passed 40 to 60 times to obtain a secondary masterbatch; The secondary masterbatch is left to stand for 20 to 30 hours to obtain a film with a thickness of 1 mm. After drying, an activator, an antioxidant, an anti-wear agent, a polyester, a plasticizer, a vulcanizer, a accelerator and the third auxiliary agent are added and mixed to obtain the shaft seal rubber for the nuclear power main pump shaft.

5. The method for preparing an EPDM-based sealing material for nuclear power equipment according to claim 4, characterized in that: The multiple batches are 3 to 8 times.

6. A method for preparing a rubber sealing ring, characterized in that: include: The EPDM rubber-based sealing material and fiber fabric for nuclear power equipment according to claim 1; The second auxiliary agent is evenly applied on the surface of the fiber fabric, and after drying at room temperature, the EPDM rubber-based sealing material for nuclear power equipment according to claim 1 is simultaneously pasted on the upper and lower surfaces of the fiber fabric, and the airbag is heated and pressurized.

7. The method for preparing a rubber sealing ring according to claim 6, characterized in that: The fiber fabric is composed of at least two of carbon fiber, aramid fiber and basalt fiber.

8. The method for preparing a rubber sealing ring according to claim 6, characterized in that: The mass proportion of any fiber in the fiber fabric is not less than 30%.

9. The method for preparing a rubber sealing ring according to claim 6, characterized in that: The second auxiliary agent is evenly applied on the surface of the fiber fabric, and the dosage of the second auxiliary agent is 0.5-0.8 kg / m 2 .

10. A rubber sealing ring, characterized in that: The rubber sealing ring is prepared by the preparation method of any one of claims 6 to 9.