Low-temperature-resistant hydrogenated butadiene-acrylonitrile rubber for high-pressure and high-rotating-speed oil seal, preparation method and oil seal

Abstract

The invention relates to the technical field of rubber sealing materials, and discloses low-temperature-resistant hydrogenated butadiene-acrylonitrile rubber for a high-pressure and high-rotating-speed oil seal, a preparation method and the oil seal. The low-temperature-resistant hydrogenated butadiene-acrylonitrile rubber for the high-pressure and high-rotation-speed oil seal comprises the following components in parts by weight: 100.0 parts of HNBR raw rubber, 1.0 part of stearic acid, 1.0 part of an anti-aging agent, 1.0 part of microcrystalline wax, 5.0 parts of PTFE, 65.0 to 75.0 parts of carbon black, 13.0 to 17.0 parts of a plasticizer DOS, 5.0 to 10.0 parts of a vulcanizing agent DCP-40 and 2.0 to 4.0 parts of an accelerant PM. The low-temperature-resistant hydrogenated butadiene-acrylonitrile rubber is reasonable in design and simple in preparation method, the raw rubber ZP4310, the plasticizer DOS, the carbon black Cabot N550 and the vulcanizing agent DCP-40 are used in cooperation, it is further guaranteed that the low-temperature-resistant hydrogenated butadiene-acrylonitrile rubber for the high-pressure and high-rotation-speed oil seal has good hardness and tensile strength, and the low-temperature-resistant hydrogenated butadiene-acrylonitrile rubber is suitable for extreme working conditions such as low temperature of-40 DEG C to 120 DEG C, high pressure and high rotation speed and the like; according to the high-low-temperature-resistant nitrile rubber for sealing the high-pressure oil cylinder rod, disclosed by the invention, all the components are reasonably proportioned, so that the nitrile rubber is excellent in physical performance.

Description

Technical Field

[0001] The invention relates to the technical field of rubber sealing materials, in particular to a low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seals, a preparation method and an oil seal. Background Art

[0002] Oil seals are common mechanical components for sealing oil, also known as rotating shaft lip seals. The high-pressure and high-speed operating conditions of oil seals for engineering machinery pumps, motors, etc. generally refer to normal pressures of 0.3-0.4Mpa, limit pressures of 1-2Mpa, and linear speeds of less than 5m / s. This operating condition has high performance requirements for the material of the oil seal.

[0003] In the prior art, fluororubber is generally used as the rubber raw material to manufacture oil seals in non-low temperature working conditions (-25 to 150°C). However, ordinary fluororubber is not resistant to low temperatures, so it cannot be used in low temperature working conditions (-40 to 120°C). If low temperature resistant fluororubber is used in low temperature working conditions (-40 to 120°C), its high cost does not make it mass-producible; and the common low temperature resistant material nitrile rubber cannot be used, because under high pressure and high speed conditions, the oil seal lip will heat up rapidly, and the nitrile rubber with poor heat resistance will easily crack, which will make the sealing performance of the high pressure and high speed oil seal fail, resulting in the risk of oil leakage in the high pressure and high speed oil cylinder. Therefore, there is an urgent need for a rubber material that can be applied to extreme working conditions such as low temperature resistance, high pressure and high speed. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seals and a preparation method and an oil seal. The low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seals has the characteristics of being resistant to low temperatures (-40 to 120°C) and high pressure and high speed under extreme working conditions, and meets the physical performance requirements of high-pressure and high-speed oil cylinders.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seals, comprising the following components in parts by weight:

[0007] HNBR raw rubber: 100.0 parts,

[0008] Stearic acid: 1.0 parts

[0009] Anti-aging agent: 1.0 part,

[0010] Microcrystalline wax: 1.0 parts,

[0011] PTFE (polytetrafluoroethylene): 5.0 parts,

[0012] Carbon black: 65.0-75.0 parts,

[0013] Plasticizer DOS: 13.0-17.0 parts,

[0014] Curing agent DCP-40: 5.0~10.0 parts,

[0015] Accelerator PM: 2.0~4.0 parts.

[0016] Furthermore, the composition comprises the following components in parts by weight:

[0017] HNBR raw rubber: 100.0 parts,

[0018] Stearic acid: 1.0 parts

[0019] Anti-aging agent: 1.0 part,

[0020] Microcrystalline wax: 1.0 parts,

[0021] PTFE: 5.0 parts,

[0022] Carbon black: 70.0 parts,

[0023] Plasticizer DOS: 15.0 parts,

[0024] Curing agent DCP-40: 7.0 parts,

[0025] Accelerator PM: 3.0 parts.

[0026] Furthermore, the brand of the HNBR raw rubber is ZP4310.

[0027] Furthermore, the grade of the carbon black is N550.

[0028] A method for preparing the low temperature resistant hydrogenated nitrile rubber for high pressure and high speed oil seal as described above specifically comprises the following steps:

[0029] Step S1, adding HNBR raw rubber into an internal mixer for primary internal mixing;

[0030] Step S2, adding stearic acid, an antioxidant and stearic acid, and performing secondary banburying;

[0031] Step S3, adding PTFE, carbon black and plasticizer DOS, and performing three times of banburying;

[0032] Step S4, reversing the internal mixing, cleaning and removing the glue after the internal mixing is completed, so as to obtain a mixed rubber;

[0033] Step S5, adding the mixed rubber into an open mill, adding a vulcanizing agent DCP-40 and an accelerator PM after the mixed rubber is rolled, and performing open milling to obtain a low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seals.

[0034] Furthermore, the mixer speed is 30 rpm, the initial mixer temperature is 60° C., the first mixer time is 1 min, the second mixer time is 1.5 min, the third mixer time is 1.5 min, the reverse mixer time is 20 s, and the cleaning time after the mixer is completed is 1 min.

[0035] Furthermore, the rotation speed of the mixing mill is set to 22 rpm, and the roller temperature is set to 38°C.

[0036] An oil seal, the oil seal sleeve is arranged on the piston rod of the oil cylinder, and comprises a rubber part, the rubber part has a metal skeleton built in it for supporting, and the rubber part is made of the low temperature resistant hydrogenated nitrile rubber for high pressure and high speed oil seal as mentioned above;

[0037] The metal skeleton includes a first metal skeleton and a second metal skeleton, both of which are annular skeletons, and the second metal skeleton has an L-shaped cross-section; the first metal skeleton structure matches the rubber part structure, and the second metal skeleton is buckled on top of the first metal skeleton and there is a gap between the first metal skeleton and the second metal skeleton.

[0038] Furthermore, the rubber part includes a main body, and an oil lip and a dust lip are respectively provided at the main body near the cylinder piston rod. The oil lip and the dust lip are respectively located on both sides of the main body and protrude outward along the axial direction of the main body; the outer wall of the oil lip is provided with a ring groove for accommodating a spring, and the inner wall of the oil lip is provided with a V-shaped protrusion; the dust lip is a convex ring inclined from the main body toward the cylinder piston rod.

[0039] Furthermore, the minimum inner diameter R1 of the oil lip is smaller than the minimum inner diameter R2 of the dust lip.

[0040] The beneficial effects of the present invention are as follows: the present invention has reasonable design and simple preparation method, and the raw rubber ZP4310, the plasticizer DOS, the carbon black (Cabot N550) and the vulcanizing agent DCP-40 are used in combination to further ensure that the low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seals has good hardness and tensile strength, and is suitable for extreme working conditions such as low temperature resistance (-40°C to 120°C), high pressure and high speed; the high-temperature resistant nitrile rubber for high-pressure oil cylinder rod seals of the present invention has excellent physical properties through the reasonable proportion of each component. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 Schematic diagram of the cross-sectional structure of an oil seal according to an embodiment of the present invention.

[0043] In the figure: 1. first metal frame, 2. second metal frame, 3. rubber part, 4. spring, 31. oil lip part, 32. dust lip part. DETAILED DESCRIPTION

[0044] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0045] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0046] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] A low temperature resistant hydrogenated nitrile rubber for high pressure and high speed oil seal, characterized by comprising the following components in parts by weight:

[0048] HNBR raw rubber: 100.0 parts,

[0049] Stearic acid: 1.0 parts

[0050] Anti-aging agent: 1.0 part,

[0051] Microcrystalline wax: 1.0 parts,

[0052] PTFE: 5.0 parts,

[0053] Carbon black: 65.0-75.0 parts,

[0054] Plasticizer DOS: 13.0-17.0 parts,

[0055] Curing agent DCP-40: 5.0~10.0 parts,

[0056] Accelerator PM: 2.0~4.0 parts.

[0057] The brand of HNBR raw rubber is ZP4310 (manufacturer: Ruiong), the brand of carbon black is N550 (manufacturer: Cabot), and the manufacturer of plasticizer DOS is Lanfan Chemical.

[0058] The present invention also discloses a preparation method for preparing the above-mentioned low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seals, which specifically comprises the following steps:

[0059] Step S1, adding HNBR raw rubber into an internal mixer for primary internal mixing;

[0060] Step S2, adding stearic acid, an antioxidant and stearic acid, and performing secondary banburying;

[0061] Step S3, adding PTFE, carbon black and plasticizer DOS twice, and performing three times of banburying;

[0062] Step S4, reversing the internal mixing, cleaning and removing the glue after the internal mixing is completed, so as to obtain a mixed rubber;

[0063] Step S5, adding the mixed rubber into an open mill, adding a vulcanizing agent DCP-40 and an accelerator PM after the mixed rubber is rolled, and performing open milling to obtain a low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seals.

[0064] The speed of the internal mixer is 30 rpm, the initial internal mixing temperature is 60°C, the first internal mixing time is 1 min, the second internal mixing time is 1.5 min, the third internal mixing time is 1.5 min, the reverse internal mixing time is 20 s, and the cleaning time after the internal mixing is 1 min.

[0065] The mill speed was set at 22 rpm and the roll temperature was set at 38°C.

[0066] like Figure 1 As shown, the present invention also discloses an oil seal, including a rubber part 3, in which a metal skeleton playing a supporting role is built-in, and the rubber part is made of the above-mentioned low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seal; the metal skeleton includes a first metal skeleton 1 and a second metal skeleton 2, the first metal skeleton 1 and the second metal skeleton 2 are both annular skeletons, and the cross-section of the second metal skeleton 2 is L-shaped; the structure of the first metal skeleton 1 matches the structure of the rubber part 3, and the second metal skeleton 2 is buckled above the first metal skeleton 1 and there is a gap between the first metal skeleton 1 and the second metal skeleton 2.

[0067] The rubber part 3 includes a main body, and an oil lip 31 and a dust lip 32 are respectively provided at the main body near the cylinder piston rod. The oil lip 31 and the dust lip 32 are respectively located on both sides of the main body and protrude outward along the axial direction of the main body; the outer wall of the oil lip 31 is provided with a ring groove for accommodating the spring 4, and the inner wall of the oil lip 31 is provided with a V-shaped protrusion; the dust lip 32 is a convex ring inclined from the main body to the cylinder piston rod.

[0068] The minimum inner diameter R1 of the oil lip 31 is smaller than the minimum inner diameter R2 of the dust lip 32 .

[0069] Example 1

[0070] The speed of the internal mixer was set to 30 rpm, and the initial temperature was set to 60°C. In the first step, 100 parts of HNBR raw rubber (ZP4310) were internally kneaded in the internal mixer for 1 min. In the second step, 1 part of stearic acid (commercially available), 1 part of antioxidant (commercially available), and 1 part of microcrystalline wax (commercially available) were added. In the third step, 5 parts of PTFE (commercially available), 70 parts of carbon black (Cabot N550), and 15 parts of plasticizer DOS (Blue Sail Chemical) were added in two batches, and the internal kneading was continued for 2 min. In the fourth step, the internal kneading was reversed for 20 s. After the internal kneading was completed, the machine was cleaned for 1 min, and the rubber was discharged to obtain the mixed rubber.

[0071] The open mill was set to rotate at 22 rpm and the roller temperature was 38°C. The mixed rubber was added to the open mill to make it roll. 7 parts of vulcanizing agent DCP-40 (commercially available) and 3 parts of accelerator PM (commercially available) were added. The left and right cutters were used 5 times, and the triangle was used. The left and right cutters were used 5 times, and the triangle was used 6 times. Finally, the hydrogenated nitrile rubber was obtained by unrolling.

[0072] Comparative Example 1

[0073] The difference between Comparative Example 1 and Example 1 is that "plasticizer DOS" is replaced by "plasticizer DBP (Blue Sail Chemical)", and the added amount of plasticizer DBP is still 15 parts.

[0074] The physical properties of Example 1 and Comparative Example 1 were tested, and the test results are shown in Table 1.

[0075] Table 1 Physical property test results of Example 1 and Comparative Example 2

[0076]

[0077] As can be seen from Table 1, the hydrogenated nitrile rubber prepared from the components in Example 1 has excellent physical properties and can meet the high and low temperature use environment of -40°C to 120°C, and is the most preferred embodiment of the present invention.

[0078] The low-temperature properties of the rubber obtained in Comparative Example 1 do not meet the requirements. This is because the plasticizer DOS has a lower solidification point, which gives the mixed rubber lower low-temperature resistance.

[0079] In addition, the plasticizer DBP in Comparative Example 1 has a greater influence on the low-temperature resistance of the rubber. After adding the plasticizer DBP, the TR10 value of the hydrogenated nitrile rubber vulcanizate is -37°C, which does not meet the application standard requirements.

[0080] Comparative Example 2

[0081] The difference between Comparative Example 2 and Example 1 is that "HNBR raw rubber (ZP4310)" is replaced by "HNBR raw rubber (ZP3310)", and the added amount of HNBR raw rubber (ZP3310) is still 100 parts.

[0082] Comparative Example 3

[0083] The difference between Comparative Example 3 and Example 1 is that "HNBR raw rubber (ZP4310)" is replaced by "NBR raw rubber (Nandi 1965)", and the added amount of NBR raw rubber (Nandi 1965) is still 100 parts.

[0084] Physical properties of Example 1, Comparative Example 2 and Comparative Example 3 were tested, and the test results are shown in Table 2.

[0085] Table 2 Physical property test results of Example 1, Comparative Example 2 and Comparative Example 3

[0086]

[0087] The AN and hydrogenation rates of HNBR raw rubber (ZP4310), HNBR raw rubber (ZP3310) and NBR raw rubber (Nanti 1965) are shown in Table 3.

[0088] Table 3 Freezing point and boiling point of HNBR raw rubber (ZP4310), HNBR raw rubber (ZP3310) and NBR raw rubber (Nandi 1965)

[0089]

[0090] It can be seen from Table 2 and Table 3 that the hydrogenated nitrile rubber prepared from the components in Example 1 has excellent physical properties and can meet the high and low temperature use environment of -40°C to 120°C, and is the most preferred embodiment of the present invention.

[0091] The low temperature characteristics of comparative example 2 do not meet the requirements, and the high temperature characteristics of comparative example 3 do not meet the requirements. Example 1 uses ZP4310 as HNBR raw rubber, and its higher hydrogenation rate ensures its high temperature resistance, while its lower AN% content gives it ultra-low low temperature resistance.

[0092] In Comparative Example 2, the AN content of ZP3310 is relatively high. When the AN content increases, the interaction between the molecular chains increases and the flexibility of the molecular chains decreases, which makes it more difficult for the molecular chains to move at low temperatures, thereby increasing Tg and reducing low temperature resistance. After adding ZP3310 to Comparative Example 2, the TR10 value of the hydrogenated nitrile rubber vulcanizate is -32°C, which does not meet the application standard requirements.

[0093] In Comparative Example 3, Nandi 1965 is used as NBR rubber, and its high temperature resistance is worse than that of HNBR, because Nandi 1965 contains a large number of carbon-carbon double bonds in the molecular chain, and the carbon-carbon double bonds have high reactivity. In a high temperature environment, the double bonds are easily attacked by factors such as heat and oxygen, and an oxidation reaction occurs; oxygen molecules can react with the double bonds to form peroxide intermediates, which are extremely unstable and will further decompose to produce free radicals, triggering a chain reaction, resulting in the breakage or cross-linking of the rubber molecular chain. After Nandi 1965 is added to Comparative Example 3, the high temperature compression permanent deformation, hot air aging and oil resistance of the nitrile rubber at high temperature decrease, and the application standard requirements are not met.

[0094] Example 2

[0095] The speed of the internal mixer was set to 30 rpm, and the initial temperature was set to 60°C. In the first step, 100 parts of HNBR raw rubber (ZP4310) were internally kneaded in the internal mixer for 1 minute. In the second step, 1 part of stearic acid (commercially available), 1 part of antioxidant (commercially available), and 1 part of microcrystalline wax (commercially available) were added. In the third step, 5 parts of PTFE (commercially available), 70 parts of carbon black (Cabot N550), and 13 parts of plasticizer DOS (Blue Sail Chemical) were added in two batches, and the internal kneading was continued for 2 minutes. In the fourth step, the internal kneading was reversed for 20 seconds. After the internal kneading was completed, the machine was cleaned for 1 minute, and the rubber was discharged to obtain the mixed rubber.

[0096] The open mill was set to rotate at 22 rpm and the roller temperature was 38°C. The mixed rubber was added to the open mill to make it roll. 7 parts of vulcanizing agent DCP-40 (commercially available) and 3 parts of accelerator PM (commercially available) were added. The left and right cutters were used 5 times, and the triangle was used. The left and right cutters were used 5 times, and the triangle was used 6 times. Finally, the hydrogenated nitrile rubber was obtained by unrolling.

[0097] Example 3

[0098] The speed of the internal mixer was set to 30 rpm, and the initial temperature was set to 60°C. In the first step, 100 parts of HNBR raw rubber (ZP4310) were internally kneaded in the internal mixer for 1 min. In the second step, 1 part of stearic acid (commercially available), 1 part of antioxidant (commercially available), and 1 part of microcrystalline wax (commercially available) were added. In the third step, 5 parts of PTFE (commercially available), 70 parts of carbon black (Cabot N550), and 17 parts of plasticizer DOS (Blue Sail Chemical) were added in two batches, and the internal kneading was continued for 2 min. In the fourth step, the internal kneading was reversed for 20 s. After the internal kneading was completed, the machine was cleaned for 1 min, and the rubber was discharged to obtain the mixed rubber.

[0099] The open mill was set to rotate at 22 rpm and the roller temperature was 38°C. The mixed rubber was added to the open mill to make it roll. 7 parts of vulcanizing agent DCP-40 (commercially available) and 3 parts of accelerator PM (commercially available) were added. The left and right cutters were used 5 times, and the triangle was used. The left and right cutters were used 5 times, and the triangle was used 6 times. Finally, the hydrogenated nitrile rubber was obtained by unrolling.

[0100] The physical properties of Example 1, Example 2 and Example 3 were tested, and the test results are shown in Table 4.

[0101] Table 4 Physical property test results of Example 1, Example 2 and Example 3

[0102]

[0103]

[0104] As can be seen from Table 4, the hydrogenated nitrile rubber prepared from the components in Example 1 has excellent physical properties and can meet the high and low temperature use environment of -40°C to 120°C, and is the most preferred embodiment of the present invention.

[0105] Compared with Example 1 and Example 2 and Example 3, only the weight portion of the plasticizer DOS added was changed.

[0106] When 13 parts of plasticizer DOS were added in Example 2, the low temperature resistance and elongation at break of the prepared hydrogenated nitrile rubber would slightly decrease, and the tensile strength and hardness would slightly increase. When 18 parts of plasticizer DOS were added in Example 3, the performances were opposite, but all within the target range.

[0107] The present invention adopts plasticizer DOS because more plasticizer DOS is distributed between macromolecular chains, which can reduce the intermolecular force and give the rubber more softness, elasticity and low temperature resistance.

[0108] Example 4

[0109] The speed of the internal mixer was set to 30 rpm, and the initial temperature was set to 60°C. In the first step, 100 parts of HNBR raw rubber (ZP4310) were internally kneaded in the internal mixer for 1 min. In the second step, 1 part of stearic acid (commercially available), 1 part of antioxidant (commercially available), and 1 part of microcrystalline wax (commercially available) were added. In the third step, 5 parts of PTFE (commercially available), 70 parts of carbon black (Cabot N550), and 15 parts of plasticizer DOS (Blue Sail Chemical) were added in two batches, and the internal kneading was continued for 2 min. In the fourth step, the internal kneading was reversed for 20 s. After the internal kneading was completed, the machine was cleaned for 1 min, and the rubber was discharged to obtain the mixed rubber.

[0110] The speed of the open mill was set to 22 rpm, the roller temperature was 38°C, the mixed rubber was added to the open mill to make it roll, and 5 parts of vulcanizing agent DCP-40 (commercially available) and 3 parts of accelerator PM (commercially available) were added. The left and right cutters were used 5 times, and the triangle was used. The left and right cutters were used 5 times, and the triangle was used 6 times. Finally, the hydrogenated nitrile rubber was obtained by unrolling.

[0111] Example 5

[0112] The speed of the internal mixer was set to 30 rpm, and the initial temperature was set to 60°C. In the first step, 100 parts of HNBR raw rubber (ZP4310) were internally kneaded in the internal mixer for 1 min. In the second step, 1 part of stearic acid (commercially available), 1 part of antioxidant (commercially available), and 1 part of microcrystalline wax (commercially available) were added. In the third step, 5 parts of PTFE (commercially available), 70 parts of carbon black (Cabot N550), and 15 parts of plasticizer DOS (Blue Sail Chemical) were added in two batches, and the internal kneading was continued for 2 min. In the fourth step, the internal kneading was reversed for 20 s. After the internal kneading was completed, the machine was cleaned for 1 min, and the rubber was discharged to obtain the mixed rubber.

[0113] The speed of the open mill was set to 22 rpm, the roller temperature was 38°C, the mixed rubber was added to the open mill to make it roll, and 8 parts of vulcanizing agent DCP-40 (commercially available) and 3 parts of accelerator PM (commercially available) were added. The left and right cutters were used 5 times, and the triangle was used. The left and right cutters were used 5 times, and the triangle was used 6 times. Finally, the hydrogenated nitrile rubber was obtained by unrolling.

[0114] Example 6

[0115] The speed of the internal mixer was set to 30 rpm, and the initial temperature was set to 60°C. In the first step, 100 parts of HNBR raw rubber (ZP4310) were internally kneaded in the internal mixer for 1 min. In the second step, 1 part of stearic acid (commercially available), 1 part of antioxidant (commercially available), and 1 part of microcrystalline wax (commercially available) were added. In the third step, 5 parts of PTFE (commercially available), 70 parts of carbon black (Cabot N550), and 15 parts of plasticizer DOS (Blue Sail Chemical) were added in two batches, and the internal kneading was continued for 2 min. In the fourth step, the internal kneading was reversed for 20 s. After the internal kneading was completed, the machine was cleaned for 1 min, and the rubber was discharged to obtain the mixed rubber.

[0116] The speed of the open mill was set to 22 rpm, the roller temperature was 38°C, the mixed rubber was added to the open mill to make it roll, and 10 parts of vulcanizing agent DCP-40 (commercially available) and 3 parts of accelerator PM (commercially available) were added. The left and right cutters were used 5 times, and the triangle was used. The left and right cutters were used 5 times, and the triangle was used 6 times. Finally, the hydrogenated nitrile rubber was obtained by unrolling.

[0117] Physical properties of Example 1 and Example 4 to Example 6 were tested, and the test results are shown in Table 5.

[0118] Table 5 Physical property test results of Example 1, Example 4 to Example 6

[0119]

[0120]

[0121] As can be seen from Table 5, the hydrogenated nitrile rubber prepared from the components in Example 1 has excellent physical properties and can meet the high and low temperature use environment of -40°C to 120°C, and is the most preferred embodiment of the present invention.

[0122] Compared with Example 1 and Example 4 to Example 6, only the weight portion of the vulcanizing agent DCP-40 added was changed.

[0123] When 5 parts of the vulcanizing agent DCP-40 were added in Example 4, the tensile strength, M100 and vulcanization speed of the prepared hydrogenated nitrile rubber were slightly lower. When 10 parts of the vulcanizing agent DCP-40 were added in Example 6, the performances were opposite, but all within the target range.

[0124] The present invention adopts the vulcanizing agent DCP-40 because a higher content of the vulcanizing agent DCP-40 increases the vulcanization speed and cross-linking density of the rubber, thereby increasing the strength of the rubber.

[0125] Example 7

[0126] The speed of the internal mixer was set to 30 rpm, and the initial temperature was set to 60°C. In the first step, 100 parts of HNBR raw rubber (ZP4310) were internally kneaded in the internal mixer for 1 min. In the second step, 1 part of stearic acid (commercially available), 1 part of antioxidant (commercially available), and 1 part of microcrystalline wax (commercially available) were added. In the third step, 5 parts of PTFE (commercially available), 65 parts of carbon black (Cabot N550), and 15 parts of plasticizer DOS (Blue Sail Chemical) were added in two batches, and the internal kneading was continued for 2 min. In the fourth step, the internal kneading was reversed for 20 s. After the internal kneading was completed, the machine was cleaned for 1 min, and the rubber was discharged to obtain the mixed rubber.

[0127] The open mill was set to rotate at 22 rpm and the roller temperature was 38°C. The mixed rubber was added to the open mill to make it roll. 7 parts of vulcanizing agent DCP-40 (commercially available) and 3 parts of accelerator PM (commercially available) were added. The left and right cutters were used 5 times, and the triangle was used. The left and right cutters were used 5 times, and the triangle was used 6 times. Finally, the hydrogenated nitrile rubber was obtained by unrolling.

[0128] Example 8

[0129] The speed of the internal mixer was set to 30 rpm, and the initial temperature was set to 60°C. In the first step, 100 parts of HNBR raw rubber (ZP4310) were internally kneaded in the internal mixer for 1 min. In the second step, 1 part of stearic acid (commercially available), 1 part of antioxidant (commercially available), and 1 part of microcrystalline wax (commercially available) were added. In the third step, 5 parts of PTFE (commercially available), 75 parts of carbon black (Cabot N550), and 15 parts of plasticizer DOS (Blue Sail Chemical) were added in two batches, and the internal kneading was continued for 2 min. In the fourth step, the internal kneading was reversed for 20 s. After the internal kneading was completed, the machine was cleaned for 1 min, and the rubber was discharged to obtain the mixed rubber.

[0130] The open mill was set to rotate at 22 rpm and the roller temperature was 38°C. The mixed rubber was added to the open mill to make it roll. 7 parts of vulcanizing agent DCP-40 (commercially available) and 3 parts of accelerator PM (commercially available) were added. The left and right cutters were used 5 times, and the triangle was used. The left and right cutters were used 5 times, and the triangle was used 6 times. Finally, the hydrogenated nitrile rubber was obtained by unrolling.

[0131] The physical properties of Example 1, Example 7 and Example 8 were tested, and the test results are shown in Table 6.

[0132] Table 6 Physical property test results of Example 1, Example 7 and Example 8

[0133]

[0134]

[0135] As can be seen from Table 6, the hydrogenated nitrile rubber prepared from the components in Example 1 has excellent physical properties and can meet the high and low temperature use environment of -40°C to 120°C, and is the most preferred embodiment of the present invention.

[0136] Compared with Example 1, Example 7 and Example 8, only the weight portion of carbon black (Cabot N550) added was changed.

[0137] When 65 parts of carbon black (Cabot N550) are added in Example 7, the elongation at break of the prepared hydrogenated nitrile rubber will increase slightly, and the tensile strength and hardness will decrease slightly. When 75 parts of carbon black (Cabot N550) are added in Example 8, the performance of each property is opposite, but all are within the target range.

[0138] The present invention uses carbon black (Cabot N550) because as the amount of carbon black increases, it can produce stronger interactions with rubber molecules, form effective physical crosslinking points, and enhance the load-bearing capacity of the rubber matrix. However, the interaction between carbon black and rubber molecules will also limit the movement of molecular chains, thereby reducing their chain flexibility.

[0139] In summary, the present invention has a reasonable design and a simple preparation method. By using raw rubber ZP4310, plasticizer DOS, carbon black (Cabot N550) and vulcanizer DCP-40 in combination, it is further ensured that the low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seals has good hardness and tensile strength, and is suitable for extreme working conditions such as low temperature resistance (-40°C to 120°C), high pressure and high speed; the high-temperature resistant nitrile rubber for high-pressure oil cylinder rod seals of the present invention has excellent physical properties through the reasonable ratio of each component.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low temperature resistant hydrogenated nitrile rubber for high pressure and high speed oil seal, characterized in that: The composition comprises the following components in parts by weight: HNBR raw rubber: 100.0 parts, Stearic acid: 1.0 parts Anti-aging agent: 1.0 part, Microcrystalline wax: 1.0 parts, PTFE: 5.0 parts, Carbon black: 65.0-75.0 parts, Plasticizer DOS: 13.0-17.0 parts, Curing agent DCP-40: 5.0~10.0 parts, Accelerator PM: 2.0~4.0 parts.

2. The low temperature resistant hydrogenated nitrile rubber for high pressure and high speed oil seal according to claim 1, characterized in that: The components comprising the following parts by weight: HNBR raw rubber: 100.0 parts, Stearic acid: 1.0 parts Anti-aging agent: 1.0 part, Microcrystalline wax: 1.0 parts, PTFE: 5.0 parts, Carbon black: 70.0 parts, Plasticizer DOS: 15.0 parts, Curing agent DCP-40: 7.0 parts, Accelerator PM: 3.0 parts.

3. The low temperature resistant hydrogenated nitrile rubber for high pressure and high speed oil seal according to claim 1, characterized in that: The grade of the HNBR raw rubber is ZP4310.

4. The low temperature resistant hydrogenated nitrile rubber for high pressure and high speed oil seal according to claim 1, characterized in that: The grade of the carbon black is N550.

5. A method for preparing the low temperature resistant hydrogenated nitrile rubber for high pressure and high speed oil seal according to any one of claims 1 to 4, characterized in that: The specific steps include: Step S1, adding HNBR raw rubber into an internal mixer for primary internal mixing; Step S2, adding stearic acid, an antioxidant and stearic acid, and performing secondary banburying; Step S3, adding PTFE, carbon black and plasticizer DOS, and performing three times of banburying; Step S4, reversing the internal mixing, cleaning and removing the glue after the internal mixing is completed, so as to obtain a mixed rubber; Step S5, adding the mixed rubber into an open mill, adding a vulcanizing agent DCP-40 and an accelerator PM after the mixed rubber is rolled, and performing open milling to obtain a low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seals.

6. The method for preparing the low temperature resistant hydrogenated nitrile rubber for high pressure and high speed oil seal according to claim 5, characterized in that: The mixer has a rotation speed of 30 rpm, an initial mixer temperature of 60° C., a first mixer time of 1 min, a second mixer time of 1.5 min, a third mixer time of 1.5 min, a reverse mixer time of 20 s, and a cleaning time of 1 min after the mixer is completed.

7. The method for preparing low temperature resistant hydrogenated nitrile rubber for high pressure and high speed oil seal according to claim 5, characterized in that: The mill speed was set at 22 rpm and the roller temperature was set at 38°C.

8. An oil seal, wherein the oil seal sleeve is arranged on the piston rod of the oil cylinder, characterized in that: The rubber part (3) comprises a metal frame having a supporting function built therein, and the rubber part is made of the low-temperature resistant hydrogenated nitrile rubber for high-pressure and high-speed oil seals as claimed in any one of claims 1 to 4; The metal skeleton comprises a first metal skeleton (1) and a second metal skeleton (2); the first metal skeleton (1) and the second metal skeleton (2) are both annular skeletons, and the second metal skeleton (2) has an L-shaped cross section; the structure of the first metal skeleton (1) matches the structure of the rubber part (3), and the second metal skeleton (2) is buckled on the top of the first metal skeleton (1) and there is a gap between the first metal skeleton (1) and the second metal skeleton (2).

9. The oil seal according to claim 8, characterized in that: The rubber part (3) comprises a body, and an oil lip (31) and a dust lip (32) are respectively arranged on the body near the piston rod of the oil cylinder. The oil lip (31) and the dust lip (32) are respectively located on two sides of the body and are arranged to protrude outward along the axial direction of the body. The outer wall of the oil lip (31) is provided with a ring groove for accommodating a spring (4), and the inner wall of the oil lip (31) is provided with a V-shaped protrusion. The dust lip (32) is a protruding ring arranged obliquely from the body to the piston rod of the oil cylinder.

10. The oil seal according to claim 9, characterized in that: The minimum inner diameter R1 of the oil lip (31) is smaller than the minimum inner diameter R2 of the dust lip (32).

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