Rubber gasket for carbon dioxide pressure reducing valve

Abstract

The invention relates to the technical field of rubber materials, in particular to a rubber gasket for a carbon dioxide pressure reducing valve. Comprising the following raw materials: 100 parts of raw rubber, 1-2 parts of an anti-aging agent, 4.8-7.5 parts of an active agent, 110-130 parts of a reinforcing agent, 5-12 parts of a plasticizer, 1-2 parts of a flow promoter, 0.5-1 part of an internal release agent, 1-1.5 parts of a vulcanizing agent and 4.5-5.5 parts of an accelerant. According to the rubber gasket for the carbon dioxide pressure reducing valve, the shore A hardness ranges from 87 degrees to 93 degrees, the tensile strength is larger than or equal to 14 MPa, the elongation at break is larger than or equal to 100%, the compression set (100 * 22 h) is smaller than or equal to 25%, air tightness, elasticity and hardness are all considered, and therefore leakage of the carbon dioxide pressure reducing valve can be avoided.

Description

Technical Field

[0001] The present disclosure relates to the technical field of rubber materials, and in particular to a rubber gasket for a carbon dioxide pressure reducing valve. Background Art

[0002] The carbon dioxide pressure reducing valve adjusts the flow of the medium by controlling the opening of the opening and closing parts in the valve body to reduce the pressure of the medium. At the same time, the opening of the opening and closing parts is adjusted by the pressure behind the valve to keep the pressure behind the valve within a certain range, and cooling water is sprayed into the valve body or behind the valve to reduce the temperature of the medium. This valve is called a pressure reducing and temperature reducing valve. The characteristic of this valve is that it keeps the outlet pressure and temperature values ​​within a certain range when the inlet pressure is constantly changing. The pressure reducing valve is an essential accessory of the pneumatic control valve. Its main function is to reduce the pressure of the gas source and stabilize it to a fixed value so that the control valve can obtain stable gas source power for adjustment and control.

[0003] The carbon dioxide pressure reducing valve needs to be sealed with a rubber gasket to prevent the leakage of carbon dioxide and the entry of impurities. The rubber gasket will come into contact with carbon dioxide, and its minimum operating temperature is -60℃~-50℃, and its maximum operating pressure is 8MPa-10MPa. Under such conditions of use, the rubber gasket will usually have the following phenomena: 1. The rubber gasket will expand significantly; 2. The rubber gasket is not elastic enough, and there will be obvious indentations after use (after removing the product, the indentation is very deep and cannot be restored). The above phenomena will affect the sealing of the rubber gasket, thereby causing the carbon dioxide pressure reducing valve to leak. Summary of the invention

[0004] In view of the deficiencies or problems existing in the prior art, the present invention provides a rubber gasket for a carbon dioxide pressure reducing valve, which can reduce its own expansion and has good elasticity.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: a rubber gasket for a carbon dioxide pressure reducing valve, which includes the following raw materials, by mass: 100 parts of raw rubber, 1-2 parts of an antioxidant, 4.8-7.5 parts of an active agent, 110-130 parts of a reinforcing agent, 5-12 parts of a plasticizer, 1-2 parts of a flow aid, 0.5-1 parts of an internal release agent, 1-1.5 parts of a vulcanizer, and 4.5-5.5 parts of an accelerator.

[0006] Preferably, the raw rubber is nitrile rubber; the acrylonitrile content in the nitrile rubber is 31%-35%.

[0007] Nitrile rubber has good wear resistance and heat resistance. Nitrile rubber contains acrylonitrile so it presents polarity, which increases the intermolecular force, can hinder the penetration of carbon dioxide molecules, and improves its resistance to the erosion of carbon dioxide. In order to improve the polarity of nitrile rubber, the prior art usually selects nitrile rubber with acrylonitrile content of 36%-42% as raw rubber for use, although it improves the hindering effect of the material on carbon dioxide molecules, but the resilience will deteriorate. The present application selects nitrile rubber with acrylonitrile content of about 33%, taking into account air tightness and elasticity.

[0008] Preferably, the antioxidant is 1 part, and the antioxidant is 2,2,4-trimethyl 1,2-dihydroquinoline polymer, and its trade name is antioxidant RD. The dimer in antioxidant RD has good heat resistance and stability.

[0009] Preferably, the active agent is stearic acid and zinc oxide; the stearic acid is 0.8-1.5 parts, and the zinc oxide is 4-6 parts. More specifically, the stearic acid is 1 part, and the zinc oxide is 5 parts.

[0010] Stearic acid is produced by Indonesia's PALMATA 1801 Company and is used to accelerate the full diffusion of carbon black and zinc oxide, and also to increase the degree of vulcanization. Zinc oxide is used to accelerate the vulcanization speed and increase the degree of crosslinking. The use of stearic acid and zinc oxide as active agents can enhance the hardening degree of rubber.

[0011] Preferably, the reinforcing agent is N550 carbon black and N774 carbon black; the N550 carbon black is 30-40 parts, and the N774 carbon black is 80-90 parts.

[0012] N550 carbon black and N774 carbon black are both soft carbon blacks, which are used to enhance the tensile resistance of rubber. Among them, N550 carbon black has good reinforcement and elasticity, and can give the rubber a higher stiffness; N774 carbon black has a relatively large particle size and can be filled in large quantities. At the same time, it has good elasticity, wear resistance, and tear resistance, and can give the rubber high elongation, high elasticity and good aging resistance. Filling a large amount of carbon black can increase the density of the rubber, hinder dioxide erosion, and increase the hardness of the rubber. High hardness can improve the ability of the finished material to resist high pressure. The present application improves the elasticity of the material on the basis of meeting the hardness requirements by selecting suitable types of carbon black and the ratio between different types of carbon black.

[0013] Preferably, the plasticizer is trioctyl trimellitate, and the amount used is 8 parts.

[0014] Preferably, the flow aid is Honeywell AC 617A wax powder, and the dosage is 1.5 parts.

[0015] Preferably, the internal mold release agent is WB222, and the dosage is 0.5 parts. WB222 is a saturated fatty acid ester flow dispersant, which can improve the processing performance of polar rubber, the fluidity and demoulding properties of the rubber compound.

[0016] Preferably, the vulcanizing agent is S-80, and the amount used is 1.2 parts.

[0017] Preferably, the accelerators are vulcanization accelerator M, vulcanization accelerator TBBS, TMTD and TETD-75; wherein, the vulcanization accelerator M is 0.3 parts, the vulcanization accelerator TBBS is 1.5 parts, the TMTD is 1.5 parts, and the TETD-75 is 1.5 parts.

[0018] TBBS is a sulfonamide vulcanization accelerator, which does not produce carcinogens in the process of promoting rubber vulcanization, which is in line with the concept of green environmental protection; TMTD and TETD-75 have very strong vulcanization promoting power in the presence of zinc oxide; TETD-75 is an ultra-fast vulcanization accelerator. By increasing the amount of vulcanizer and accelerator, the cross-linking density is increased, thereby improving the air tightness and elasticity of the material. In addition, this application uses a variety of accelerators, and the combination of multiple accelerators can increase the scorch time and ensure the smooth production of the product.

[0019] Compared with the prior art, the rubber gasket for the carbon dioxide pressure reducing valve of the present invention has a Shore A hardness of 87-93 degrees, a tensile strength greater than or equal to 14 MPa, an elongation at break greater than or equal to 100%, and a compression permanent deformation (100*22h) less than or equal to 25%, taking into account air tightness, elasticity and hardness, thereby preventing leakage of the carbon dioxide pressure reducing valve; the present application increases the cross-linking density by increasing the amount of vulcanizer and accelerator, thereby improving the air tightness and elasticity of the material. DETAILED DESCRIPTION Example 1

[0020] This embodiment provides a rubber gasket for a pressure reducing valve, which includes the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 1 part of RD, 0.8 parts of stearic acid, 4 parts of zinc oxide, 30 parts of N550 carbon black, 80 parts of N774 carbon black, 5 parts of trioctyl trimellitate, 1 part of Honeywell AC 617A wax powder, 0.5 parts of WB222, 1 part of S-80, 1.5 parts of TMTD, 1.5 parts of TBBS, 0.3 parts of M, and 1.5 parts of TETD-75. Example 2

[0021] This embodiment provides a rubber gasket for a pressure reducing valve, which includes the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 1.5 parts of RD, 1 part of stearic acid, 5 parts of zinc oxide, 32 parts of N550 carbon black, 86 parts of N774 carbon black, 7 parts of trioctyl trimellitate, 1.6 parts of Honeywell AC 617A wax powder, 0.6 parts of WB222, 1.2 parts of S-80, 1.5 parts of TMTD, 1.5 parts of TBBS, 0.3 parts of M, and 1.5 parts of TETD-75. Example 3

[0022] This embodiment provides a rubber gasket for a pressure reducing valve, which includes the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 1.8 parts of RD, 1.5 parts of stearic acid, 6 parts of zinc oxide, 40 parts of N550 carbon black, 90 parts of N774 carbon black, 10 parts of trioctyl trimellitate, 1.5 parts of Honeywell AC 617A wax powder, 0.9 parts of WB222, 1.4 parts of S-80, 1.5 parts of TMTD, 1.5 parts of TBBS, 0.3 parts of M, and 1.5 parts of TETD-75. Example 4

[0023] This embodiment provides a rubber gasket for a pressure reducing valve, which includes the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 1.2 parts of RD, 1.2 parts of stearic acid, 5.5 parts of zinc oxide, 35 parts of N550 carbon black, 85 parts of N774 carbon black, 8 parts of trioctyl trimellitate, 1.3 parts of Honeywell AC 617A wax powder, 0.8 parts of WB222, 1.3 parts of S-80, 1.5 parts of TMTD, 1.5 parts of TBBS, 0.3 parts of M, and 1.5 parts of TETD-75. Example 5

[0024] This embodiment provides a rubber gasket for a pressure reducing valve, which includes the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 2 parts of RD, 1.5 parts of stearic acid, 6 parts of zinc oxide, 36 parts of N550 carbon black, 88 parts of N774 carbon black, 11 parts of trioctyl trimellitate, 2 parts of Honeywell AC 617A wax powder, 1 part of WB222, 1.5 parts of S-80, 1.5 parts of TMTD, 1.5 parts of TBBS, 0.3 parts of M, and 1.5 parts of TETD-75. Example 6

[0025] This embodiment provides a rubber gasket for a pressure reducing valve, which includes the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 1.6 parts of RD, 1.5 parts of stearic acid, 4.5 parts of zinc oxide, 38 parts of N550 carbon black, 89 parts of N774 carbon black, 12 parts of trioctyl trimellitate, 1.8 parts of Honeywell AC 617A wax powder, 0.7 parts of WB222, 1.4 parts of S-80, 1.5 parts of TMTD, 1.5 parts of TBBS, 0.3 parts of M, and 1.5 parts of TETD-75. Example 7

[0026] This embodiment provides a rubber gasket for a pressure reducing valve, which includes the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 1.1 parts of RD, 1.1 parts of stearic acid, 4.8 parts of zinc oxide, 33 parts of N550 carbon black, 83 parts of N774 carbon black, 6 parts of trioctyl trimellitate, 1.2 parts of Honeywell AC 617A wax powder, 0.5 parts of WB222, 1.2 parts of S-80, 1.5 parts of TMTD, 1.5 parts of TBBS, 0.3 parts of M, and 1.5 parts of TETD-75. Example 8

[0027] This embodiment provides a rubber gasket for a pressure reducing valve, which includes the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 1.3 parts of RD, 1.5 parts of stearic acid, 5.2 parts of zinc oxide, 35 parts of N550 carbon black, 84 parts of N774 carbon black, 9 parts of trioctyl trimellitate, 1.4 parts of Honeywell AC 617A wax powder, 0.6 parts of WB222, 1.1 parts of S-80, 1.5 parts of TMTD, 1.5 parts of TBBS, 0.3 parts of M, and 1.5 parts of TETD-75.

[0028] The rubber gaskets of Examples 1 to 8 are now subjected to relevant performance tests: 1. Installation test: The rubber gaskets in the above embodiment were assembled on a carbon dioxide pressure reducing valve, and the carbon dioxide pressure reducing valve was placed at a temperature of -60°C and a pressure of 10 MPa for 24 hours. The above eight gaskets showed no expansion and no indentation.

[0029] 2. Performance Testing (1) The tensile strength and elongation at break shall be measured in accordance with GB / T 528-1998, and the Shore A hardness test shall be measured in accordance with GB / T 531-1999; (2) The static compression set test is carried out in accordance with GB / T 1683-81; The test results are as follows: Sample No. Shore A hardness (degrees) Tensile strength (MPa) Elongation at break (%) Compression set (100℃*22h) (%) Example 1 87 15.7 125 10 Example 2 88 15.5 110 12 Example 3 93 16.5 102 14 Example 4 89 15.9 111 11 Example 5 91 16.2 105 14 Example 6 88 15.5 119 15 Example 7 89 15.6 113 11 Example 8 88 15.6 116 13 It can be seen from the above test results that the amount of reinforcing agent, plasticizer and vulcanizer has a great influence on the hardness of the rubber. The increase in the amount of reinforcing agent, the decrease in the amount of plasticizer and the increase in the amount of vulcanizer will increase the hardness of the rubber. The higher the hardness of the rubber, the smaller its elongation, and the more difficult it is to process when producing products. The present application sets the reinforcing agent to 110-130 parts, wherein N550 carbon black is 30-40 parts, N774 carbon black is 80-90 parts, the plasticizer is set to 5-12 parts, and the vulcanizer is set to 1-1.5 parts, so that the finished rubber has a certain hardness, thereby having the ability to resist high pressure, and also has a certain elasticity and elongation.

[0030] Comparative Example 1 This comparative example provides a rubber gasket for a pressure reducing valve, which comprises the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 1 part of RD, 1 part of stearic acid, 5 parts of zinc oxide, 25 parts of N550 carbon black, 60 parts of N774 carbon black, 8 parts of trioctyl trimellitate, 1.5 parts of Honeywell AC 617A wax powder, 0.5 parts of WB222, 1.2 parts of S-80, 1.5 parts of TMTD, 1.5 parts of TBBS, 0.3 parts of M, and 1.5 parts of TETD-75.

[0031] The amount of N550 carbon black and N774 carbon black in this comparative example is insufficient. After testing, the Shore A hardness of the gasket is 75 degrees, the tensile strength is 14.9MPa, the elongation at break is 237%, and the compression permanent deformation (100℃*22h) is 14%. The installation test results show that the product has expansion but no indentation. The hardness of the product in this comparative example is low. This is because the amount of carbon black is too small, the material is not dense enough, and carbon dioxide easily enters the material under high pressure, causing it to expand during the installation test.

[0032] Comparative Example 2 This comparative example provides a rubber gasket for a pressure reducing valve, which comprises the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 1 part of RD, 1 part of stearic acid, 5 parts of zinc oxide, 90 parts of N550 carbon black, 8 parts of trioctyl trimellitate, 1.5 parts of Honeywell AC 617A wax powder, 0.5 parts of WB222, 1.2 parts of S-80, 1.5 parts of TMTD, 1.5 parts of TBBS, 0.3 parts of M, and 1.5 parts of TETD-75.

[0033] The comparative example does not use N774 carbon black. After testing, the Shore A hardness of the gasket is 89 degrees, the tensile strength is 16.8MPa, the elongation at break is 105%, and the compression permanent deformation (100℃*22h) is 12%. The installation test results show that the product has no expansion and severe indentation. Although the above test data meets the relevant standards, the product has indentation. This is because this comparative example only uses N550 carbon black with a smaller particle size. The smaller the particle size of carbon black, the more unfavorable it is to the elasticity of the rubber compound, resulting in severe indentation in the installation test.

[0034] Comparative Example 3 This comparative example provides a rubber gasket for a pressure reducing valve, which comprises the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 1 part of RD, 1 part of stearic acid, 5 parts of zinc oxide, 35 parts of N550 carbon black, 85 parts of N774 carbon black, 8 parts of trioctyl trimellitate, 1.5 parts of Honeywell AC 617A wax powder, 0.5 parts of WB222, 1.2 parts of S-80, 1 part of TMTD, 1 part of TBBS, 0.3 parts of M, and 1.2 parts of TETD-75.

[0035] The amount of TMTD, TBBS, and TETD-75 added in this comparative example is insufficient. After testing, the Shore A hardness of the gasket is 86 degrees, the tensile strength is 16.8MPa, the elongation at break is 138%, and the compression permanent deformation (100℃*22h) is 14%. The installation test results show that the product has a certain degree of expansion, but no indentation. The hardness of the product in this comparative example is low, which is due to the insufficient amount of accelerator, the insufficient cross-linking density of the product, and the insufficient hardness of the product, which reduces the product's ability to resist carbon dioxide erosion, so that the product expands in the installation test.

[0036] Comparative Example 4 This comparative example provides a rubber gasket for a pressure reducing valve, which comprises the following raw materials in parts by mass: 100 parts of nitrile rubber (the content of acrylonitrile in nitrile rubber is 31%-35%), 1 part of RD, 1 part of stearic acid, 5 parts of zinc oxide, 35 parts of N550 carbon black, 85 parts of N774 carbon black, 8 parts of trioctyl trimellitate, 1.5 parts of Honeywell AC 617A wax powder, 0.5 parts of WB222, 0.7 parts of S-80, 1.5 parts of TMTD, 1.5 parts of TBBS, 0.3 parts of M, and 1.5 parts of TETD-75.

[0037] The amount of S-80 added in this comparative example is insufficient. After testing, the Shore A hardness of the gasket is 85 degrees, the tensile strength is 15.9MPa, the elongation at break is 126%, and the compression permanent deformation (100℃*22h) is 15%. The installed test results show that the product has a certain degree of expansion, but no indentation. The hardness of the product in this comparative example is low, which is due to the insufficient amount of vulcanizing agent S-80, the insufficient crosslinking density affects the hardness of the product, reduces the product's ability to resist carbon dioxide erosion, and causes product expansion.

[0038] The present application is described in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the present application and its core ideas. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A rubber gasket for a carbon dioxide pressure reducing valve, characterized in that: The composition comprises the following raw materials in parts by mass: 100 parts of raw rubber, 1-2 parts of antioxidant, 4.8-7.5 parts of activator, 110-130 parts of reinforcing agent, 5-12 parts of plasticizer, 1-2 parts of flow aid, 0.5-1 part of internal release agent, 1-1.5 parts of vulcanizer and 4.5-5.5 parts of accelerator; the raw rubber is nitrile rubber; the acrylonitrile content in the nitrile rubber is 31%-35%; the reinforcing agents are N550 carbon black and N774 carbon black; the N550 carbon black is 30-40 parts and the N774 carbon black is 80-90 parts.

2. The rubber gasket for a carbon dioxide pressure reducing valve according to claim 1, characterized in that: The antioxidant is 1 part, and the antioxidant is 2,2,4-trimethyl 1,2-dihydroquinoline polymer.

3. The rubber gasket for a carbon dioxide pressure reducing valve according to claim 1, characterized in that: The active agents are stearic acid and zinc oxide; the stearic acid is 0.8-1.5 parts, and the zinc oxide is 4-6 parts.

4. The rubber gasket for a carbon dioxide pressure reducing valve according to claim 3, characterized in that: The stearic acid is 1 part, and the zinc oxide is 5 parts.

5. The rubber gasket for a carbon dioxide pressure reducing valve according to claim 1, characterized in that: The plasticizer is trioctyl trimellitate.

6. The rubber gasket for a carbon dioxide pressure reducing valve according to claim 1, characterized in that: The flow aid is Honeywell AC 617A wax powder.

7. The rubber gasket for a carbon dioxide pressure reducing valve according to claim 1, characterized in that: The internal mold release agent is WB222; the vulcanizing agent is S-80.

8. The rubber gasket for a carbon dioxide pressure reducing valve according to claim 1, characterized in that: The accelerators are vulcanization accelerator M, vulcanization accelerator TBBS, TMTD and TETD-75; wherein, the vulcanization accelerator M is 0.3 parts, the vulcanization accelerator TBBS is 1.5 parts, the TMTD is 1.5 parts, and the TETD-75 is 1.5 parts.