Preparation method of nitrile rubber sealing ring

Abstract

The invention discloses a preparation method of a nitrile rubber sealing ring, which comprises the following steps: cutting a nitrile rubber sealing strip, immersing sections on two sides in a polyisocyanate adhesive JQ-1, airing, then coating a cyanoacrylate adhesive on the section on one side or the sections on two sides, aligning the sections on the two sides, and applying pressure to bond the end surfaces on two sides of the nitrile rubber sealing strip, thereby obtaining the nitrile rubber sealing ring. And preparing the nitrile rubber sealing ring. According to the invention, the polyisocyanate adhesive JQ-1 is matched with cyanoacrylate adhesives selected from the group consisting of Litai 8400 instant adhesive, Litai 406 instant adhesive and the like to bond the section of the nitrile rubber sealing strip, so that the bonding part of the sealing ring is endowed with certain lubricating grease resistance, and the bonding performance of the bonding part of the sealing strip after lubricating grease resistance reaches more than 1MPa; the sealing strip can be prevented from being cracked too early during use and can be applied to wind power, engineering machinery bearings and other scenes, and the service life of the sealing ring can reach 3-4 years.

Description

Technical Field

[0001] The invention belongs to the field of nitrile rubber seals and relates to a method for preparing a bearing seal, in particular to a method for preparing a nitrile rubber sealing ring. Background Art

[0002] Bearings are key components in numerous devices, primarily composed of an inner ring, outer ring, cage, rolling elements, lubricant, and seals. Seals primarily prevent the leakage of grease from the bearing and the ingress of foreign matter such as dust and rainwater. There are three main methods for forming sealing strips: direct ring formation by vulcanization molding, hot vulcanization bonding, and adhesive bonding.

[0003] Vulcanization molding directly into rings is vulcanized on molding equipment. It has the characteristics of good integrity and high tensile strength and is generally installed during the bearing assembly process. Hot vulcanization bonding is generally made by combining microwave, hot air vulcanized or hot air vulcanized sealing strips with hot vulcanized adhesive films, and then vulcanizing and bonding them into rings through hot vulcanization bonding equipment. Compared with vulcanization molding direct ring formation, hot vulcanization bonding has the characteristics of low cost and is generally installed during the bearing assembly process. Glue bonding is generally made by combining microwave, hot air vulcanized or hot air vulcanized sealing strips with instant glue to form rings directly by hand. It has the advantages of easy and quick operation, no need for tooling equipment, and is suitable for operation in small spaces. It can be installed in the bearing assembly process, can also be directly operated on fans and engineering machinery equipment, and is also suitable for repair and replacement of damaged sealing strips. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing a nitrile rubber sealing ring. By screening out heat-set glue, the grease resistance of the sealing ring glue bonding point can be improved. The sealing ring is applied to scenes such as wind power and engineering machinery bearings and has a long service life.

[0005] The technical solution of the present invention is:

[0006] A method for preparing a nitrile rubber sealing ring comprises the following steps: cutting a nitrile rubber sealing strip, immersing sections on both sides in polyisocyanate adhesive JQ-1, drying the sections, then coating one section or both sections with cyanoacrylate adhesive, aligning the sections on both sides, and applying pressure to bond the end faces of the adhesive sealing strip to obtain the nitrile rubber sealing ring.

[0007] Preferably, the cross sections on both sides are immersed in JQ-1 for 5 to 10 seconds. The present invention controls the cross section dipping time to avoid insufficient grease resistance at the bonding point due to a too short dipping time, and insufficient grease resistance at the bonding point due to a too long dipping time, which may cause the sealing strip to swell and affect the size, and may also cause the glue to cure slowly and make bonding difficult.

[0008] Preferably, the preparation method of the nitrile rubber sealing ring includes: cutting the nitrile rubber sealing strip, immersing the cross sections on both sides in polyisocyanate glue JQ-1 for 5 to 10 seconds, taking it out, drying it, and then coating Loctite 8400 instant adhesive or Loctite 406 instant adhesive on one side or both sides of the cross section, aligning the cross sections on both sides and applying pressure for 30 to 60 seconds to achieve bonding of the end faces of the adhesive sealing strip on both sides.

[0009] Considering that the two sides of the cross section need to be butted together during the bonding process, the glue will naturally infiltrate the other side. In the specific operation, it is preferred to apply cyanoacrylate adhesive on one side of the cross section.

[0010] The cyanoacrylate adhesive is Loctite 8400 instant adhesive or Loctite 406 instant adhesive.

[0011] The nitrile rubber sealing strip is made of the following components in parts by weight: 100 parts of nitrile rubber 2865C, 10-30 parts of carbon black N774, 50-70 parts of carbon black N550, 5-15 parts of plasticizer DOS, 5-8 parts of zinc oxide, 0.5-2 parts of stearic acid, 1.5-2.5 parts of antioxidant RD, 0.5-1.5 parts of antioxidant MB, 2-4 parts of antioxidant 4010NA, 1-2 parts of microcrystalline wax 9108, 5-10 parts of calcium oxide, 1-3 parts of rubber additive WB222, 0.4-1 part of sulfur, 1-2.5 parts of accelerator TMTD, 1-2 parts of accelerator DM, and 1-2 parts of accelerator DTDM.

[0012] Preferably, the nitrile rubber sealing strip is made of the following components in parts by weight: 100 parts of nitrile rubber 2865C, 25 parts of carbon black N774, 55 parts of carbon black N550, 8 parts of plasticizer DOS, 5 parts of zinc oxide, 1 part of stearic acid, 2 parts of antioxidant RD, 1 part of antioxidant MB, 3 parts of 4010NA, 1.5 parts of microcrystalline wax 9108, 8 parts of calcium oxide, 1.5 parts of rubber additive WB222, 0.8 part of sulfur, 2 parts of accelerator TMTD, 1.5 parts of accelerator DM, and 2 parts of accelerator DTDM.

[0013] A method for preparing the nitrile rubber sealing strip comprises the following steps:

[0014] Step (1), premixing nitrile rubber 2865C, zinc oxide, stearic acid, antioxidant RD, antioxidant MB, 4010NA, microcrystalline wax 9108, and rubber additive WB222 in an internal mixer for 40 seconds, then adding carbon black N774, carbon black N550, and plasticizer DOS, continuing to mix, and unloading when the internal mixer is heated to 140°C;

[0015] Step (2), the mixture obtained in step (1) is thin-passed on an open mill for three times, then pressed into sheets, cooled and left for 16 to 24 hours to obtain a masterbatch;

[0016] Step (3), adding the masterbatch together with sulfur, accelerator TMTD, accelerator DM, accelerator DTDM, and calcium oxide into an internal mixer for mixing, and unloading when the temperature of the internal mixer rises to 80° C.;

[0017] Step (4), the mixture obtained in step (3) is thinly passed through an open mill twice, rolled twice, and then pressed into strips, and then allowed to stand for 16 to 24 hours after cooling to obtain a rubber mix;

[0018] Step (5), feeding the mixed rubber into an extruder, wherein the temperatures of barrel 1, barrel 2, screw and die are respectively 65°C, 65°C, 60°C and 70°C, extruding the rubber strip at an extrusion speed of 3m / min, and vulcanizing and molding the rubber strip through hot air. The temperatures of the hot air drying tunnels of sections 1-5 are respectively 240°C, 220°C, 220°C, 220°C and 240°C, and then cooling the strip through water to obtain a nitrile rubber sealing strip.

[0019] Beneficial effects of the present invention:

[0020] The -NCO group of polyisocyanate adhesive JQ-1 reacts with moisture in the air and solidifies, firmly adsorbing on the end face of the sealing strip. The main component of cyanoacrylate adhesive is α-cyanoacrylate, which also undergoes a polyaddition reaction under water catalysis to form a polymer. The bonding of objects is achieved by the tension between the cured polymers.

[0021] The present invention uses polyisocyanate glue JQ-1 and a cyanoacrylate adhesive selected from Loctite 8400 instant glue, Loctite 406 instant glue, etc. to bond the cross-section of the nitrile rubber sealing strip, thereby giving the bonding part of the sealing ring a certain grease resistance. The grease resistance is excellent, and the grease resistance of the bonding part of the sealing strip reaches a post-grease adhesion performance of >1MPa, which can prevent the sealing strip from cracking prematurely during use. It can be applied to scenes such as wind power and engineering machinery bearings. The service life of the sealing ring can reach 3 to 4 years. In contrast, the service life of a sealing strip with poor grease resistance at the bonding part is less than half a year. DETAILED DESCRIPTION

[0022] Example 1

[0023] A nitrile rubber sealing strip is prepared from the following components in parts by weight: 100 parts of nitrile rubber 2865C, 25 parts of carbon black N774, 55 parts of carbon black N550, 8 parts of plasticizer DOS, 5 parts of zinc oxide, 1 part of stearic acid, 2 parts of antioxidant RD, 1 part of antioxidant MB, 3 parts of antioxidant 4010NA, 1.5 parts of microcrystalline wax 9108, 8 parts of calcium oxide (defoaming agent), 1.5 parts of rubber additive WB222, 0.8 part of sulfur, 2 parts of accelerator TMTD, 1.5 parts of accelerator DM, and 2 parts of accelerator DTDM.

[0024] The preparation method of the nitrile rubber sealing strip comprises the following steps:

[0025] Step (1), premixing nitrile rubber 2865C, zinc oxide, stearic acid, antioxidant RD, antioxidant MB, antioxidant 4010NA, microcrystalline wax 9108, and rubber additive WB222 in an internal mixer for 40 seconds, then adding carbon black N774, carbon black N550, and plasticizer DOS, continuing to mix, and unloading when the internal mixer is heated to 140°C;

[0026] Step (2), the mixture obtained in step (1) is thin-passed on an open mill for three times, and then the mixture is pressed into a sheet, and then left to stand for at least 16 hours after cooling to obtain a masterbatch;

[0027] Step (3), adding the masterbatch obtained in step (2) together with sulfur, accelerator TMTD, accelerator DM, accelerator DTDM, and calcium oxide into an internal mixer for mixing, and discharging the material when the temperature of the internal mixer rises to 80° C.;

[0028] Step (4), thin-passing the mixture obtained in step (3) on an open mill twice, rolling it twice, and then pressing the mixture into strips, cooling it, and then standing it for at least 16 hours to obtain a rubber mix;

[0029] Step (5), feeding the rubber mixture obtained in step (4) into an extruder, wherein the temperatures of barrel 1, barrel 2, screw and die are respectively 65°C, 65°C, 60°C and 70°C, extruding a rubber strip at an extrusion speed of 3m / min, and vulcanizing and molding the rubber strip through hot air. The temperatures of the hot air drying tunnels in sections 1-5 are respectively 240°C, 220°C, 220°C, 220°C and 240°C, and then water-cooling is performed to obtain a nitrile rubber sealing strip.

[0030] A method for preparing a nitrile rubber sealing ring comprises the following steps: cutting a nitrile rubber sealing strip; immersing two side sections in polyisocyanate adhesive JQ-1 for 8 seconds, removing the sections, and air-drying the sections; coating one side section with 8400 instant adhesive, aligning the two side sections, applying a certain pressure with both hands for 40 seconds, and then releasing the pressure to obtain the nitrile rubber sealing ring.

[0031] Example 2

[0032] A method for preparing a nitrile rubber sealing ring comprises the following steps: taking the nitrile rubber sealing strip prepared in Example 1 and cutting it; immersing both sides of the cross section in polyisocyanate adhesive JQ-1 for 8 seconds, taking it out, and drying it; coating one side of the cross section with 406 instant adhesive, then aligning the two cross sections and applying a certain pressure with both hands for 40 seconds before releasing the pressure to prepare the nitrile rubber sealing ring.

[0033] Comparative Example 1-Comparative Example 2

[0034] A method for preparing a nitrile rubber sealing ring comprises the following steps: taking the nitrile rubber sealing strip prepared in Example 1 and cutting it; coating one cross section with the glue corresponding to Table 1; aligning the cross sections on both sides; applying a certain pressure with both hands for 40 seconds and then releasing the pressure.

[0035] Table 1. Adhesive solutions for nitrile rubber sealing strips

[0036] glue Example 1 Example 2 Comparative Example 1 Comparative Example 2 JQ-1 have have none none Loctite 8400 have have Loctite 406 have have

[0037] The experimental performance test of the above embodiment is shown in Table 2:

[0038] Table 2. Performance test results of nitrile rubber sealing strips bonded by different methods

[0039]

[0040] Note: Grease 585K resistance test conditions: The bonding area is completely immersed in grease 585K at a temperature of 60°C for 168 hours. The tensile speed for the bond strength test is 50 mm / min.

[0041] The results show that the grease resistance of the bonding part using the sealing strip bonding method of the present invention is significantly better than that using only instant glue.

[0042] The sealing strip bonding method proposed in the present invention has been described in detail through the above examples. The above examples are merely descriptions of preferred embodiments of the present invention and do not limit the concept and scope of the present invention. It is obvious that those skilled in the art can modify or appropriately change and combine the formula and preparation method described herein to implement the present invention without departing from the content, spirit and scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solution of the present invention should fall within the scope of protection of the present invention. It is particularly important to remind that all similar replacements and modifications are obvious to those skilled in the art, and they are all considered to be included in the spirit, scope and content of the present invention.

Claims

1. A method for preparing a nitrile rubber sealing ring, characterized in that: include: The nitrile rubber sealing strip is cut, and the sections on both sides are immersed in polyisocyanate glue JQ-1 and dried. Then, cyanoacrylate adhesive is applied to one section or both sections. The sections on both sides are aligned and pressure is applied to achieve bonding of the end faces of the sealing strip on both sides to obtain the nitrile rubber sealing ring.

2. The method for preparing a nitrile rubber sealing ring according to claim 1, wherein: The sections on both sides were immersed in JQ-1 for 5 to 10 seconds.

3. The method for preparing a nitrile rubber sealing ring according to claim 1 or 2, wherein: include: Cut the nitrile rubber sealing strip, immerse the sections on both sides in polyisocyanate glue JQ-1 for 5 to 10 seconds, take it out, dry it, and then apply cyanoacrylate adhesive on one section or both sections, align the sections on both sides and apply pressure for 30 to 60 seconds to achieve bonding of the end faces of the adhesive sealing strip.

4. The method for preparing a nitrile rubber sealing ring according to claim 1, wherein: Apply cyanoacrylate adhesive to one section.

5. The method for preparing a nitrile rubber sealing ring according to claim 1, wherein: The cyanoacrylate adhesive is Loctite 8400 instant adhesive or Loctite 406 instant adhesive.

6. The method for preparing a nitrile rubber sealing ring according to claim 1, wherein: The nitrile rubber sealing strip is made of the following components in parts by weight: 100 parts of nitrile rubber 2865C, 10-30 parts of carbon black N774, 50-70 parts of carbon black N550, 5-15 parts of plasticizer DOS, 5-8 parts of zinc oxide, 0.5-2 parts of stearic acid, 1.5-2.5 parts of antioxidant RD, 0.5-1.5 parts of antioxidant MB, 2-4 parts of antioxidant 4010NA, 1-2 parts of microcrystalline wax 9108, 5-10 parts of calcium oxide, 1-3 parts of rubber additive WB222, 0.4-1 part of sulfur, 1-2.5 parts of accelerator TMTD, 1-2 parts of accelerator DM, and 1-2 parts of accelerator DTDM.

7. The method for preparing a nitrile rubber sealing ring according to claim 6, wherein: The nitrile rubber sealing strip is made of the following components in parts by weight: 100 parts of nitrile rubber 2865C, 25 parts of carbon black N774, 55 parts of carbon black N550, 8 parts of plasticizer DOS, 5 parts of zinc oxide, 1 part of stearic acid, 2 parts of antioxidant RD, 1 part of antioxidant MB, 3 parts of 4010NA, 1.5 parts of microcrystalline wax 9108, 8 parts of calcium oxide, 1.5 parts of rubber additive WB222, 0.8 part of sulfur, 2 parts of accelerator TMTD, 1.5 parts of accelerator DM, and 2 parts of accelerator DTDM.

8. The method for preparing a nitrile rubber sealing ring according to claim 1 or 6, wherein: The preparation method of the nitrile rubber sealing strip comprises the following steps: Step (1), premixing nitrile rubber 2865C, zinc oxide, stearic acid, antioxidant RD, antioxidant MB, 4010NA, microcrystalline wax 9108, and rubber additive WB222 in an internal mixer for 40 seconds, then adding carbon black N774, carbon black N550, and plasticizer DOS, continuing to mix, and unloading when the internal mixer is heated to 140°C; Step (2), the mixture obtained in step (1) is thin-passed on an open mill for three times, then pressed into sheets, cooled and left for 16 to 24 hours to obtain a masterbatch; Step (3), adding the masterbatch together with sulfur, accelerator TMTD, accelerator DM, accelerator DTDM, and calcium oxide into an internal mixer for mixing, and unloading when the temperature of the internal mixer rises to 80° C.; Step (4), the mixture obtained in step (3) is thinly passed through an open mill twice, rolled twice, and then pressed into strips, and then allowed to stand for 16 to 24 hours after cooling to obtain a rubber mix; Step (5), feeding the mixed rubber into an extruder, wherein the temperatures of barrel 1, barrel 2, screw and die are respectively 65°C, 65°C, 60°C and 70°C, extruding the rubber strip at an extrusion speed of 3m / min, and vulcanizing and molding the rubber strip through hot air. The temperatures of the hot air drying tunnels in sections 1-5 are respectively 240°C, 220°C, 220°C, 220°C and 240°C, and then water-cooling is performed to obtain a nitrile rubber sealing strip.

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