Dustproof and waterproof automobile sealing plug material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of fluororubber, and particularly relates to a dustproof and waterproof automobile sealing plug material as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing a polytetrafluoroethylene fiber sieve membrane rich in a uniform microporous structure, then coating and fixing a fluororubber mixed rubber sheet by using the polytetrafluoroethylene fiber sieve membrane, enabling the fluororubber mixed rubber sheet to be tightly attached to the surface of the mixed rubber sheet, and then putting the fluororubber mixed rubber sheet into a forming mold for vulcanization forming. According to the present invention, the surface of the fluororubber can be stably subjected to primary vulcanization so as to stably leave the complete and clear convex structure on the surface of the fluororubber, and the micron-sized pits and the micron-sized grooves are formed on the surface of the fluororubber after the secondary vulcanization and the third vulcanization so as to endow the surface of the fluororubber with the super-hydrophobicity and the excellent self-cleaning ability; according to the fluororubber sealing ring, the sealing treatment is better carried out on the joint face of an automobile mechanical part, effective dustproof, waterproof and sealing performance is provided, super-hydrophobic surface modification can be achieved in the fluororubber vulcanization process, and the fluororubber sealing ring is simple in process, low in energy consumption and high in production efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of fluororubber, and in particular relates to a dustproof and waterproof automobile sealing material, a preparation method and an application thereof. Background Art

[0002] With the rapid development of high-end equipment manufacturing industry, the requirements for dustproof and waterproof performance of automotive sealing materials are becoming increasingly stringent. Traditional fluororubber seals are prone to surface wetting failure under high humidity and high temperature conditions, leading to grease leakage, seal aging and cracking, and abnormal wear. The self-cleaning properties of superhydrophobic surfaces can effectively clean dust and prevent pollution without manual assistance. In recent years, the regulation of superhydrophobic surface wettability has become a research hotspot in the field.

[0003] At present, the main technologies for preparing super-hydrophobic surfaces of fluororubber are spraying, sol-gel and chemical etching. The spraying method has low manufacturing cost and simple process for preparing super-hydrophobic surfaces, and can be used on a large scale to prepare super-hydrophobic materials. However, the coating prepared by the spraying method has insufficient adhesion to the substrate and poor durability. The sol-gel method changes the humidity and temperature of the sol through physical methods to transform the sol into a gel state, thereby forming a super-hydrophobic hierarchical structure, but it has limitations such as excessive shrinkage, formation of voids and reduced adhesion. The chemical etching method often requires expensive equipment and chemical reagents, and has problems of high energy consumption and environmental pollution. Summary of the Invention

[0004] In order to solve the above technical defects, the present invention has developed a method for preparing a dustproof and waterproof automobile sealing plugging material, which has a simple preparation process, low energy consumption, and high production efficiency. The prepared sealing plugging material has excellent dustproof and waterproof performance.

[0005] The technical solutions of the present invention are as follows: A method for preparing a dustproof and waterproof automobile sealing material comprises the following steps: The mixed rubber sheet is coated and fixed with a polytetrafluoroethylene fiber sieve membrane, then assembled into a preheated forming mold and placed in a flat vulcanizer for hot pressing. After being taken out, the polytetrafluoroethylene fiber sieve membrane and the primary vulcanized fluororubber are peeled off. The primary vulcanized fluororubber is cooled and then subjected to secondary vulcanization. After cooling again, it is subjected to tertiary vulcanization to obtain a dustproof and waterproof automotive sealing material. The polytetrafluoroethylene fiber sieve membrane is prepared by ultrasonically mixing a polytetrafluoroethylene emulsion made of polytetrafluoroethylene, deionized water, perfluoropolyether ammonium carboxylate and azobisisobutylimidazoline hydrochloride with a polyethylene glycol aqueous solution, electrospinning the emulsion, and then soaking it in hot water and ultrasonically dispersing it. The mixed rubber sheet is obtained by kneading and rolling out FFKM raw rubber into a raw rubber sheet, and then mixing it with zinc stearate, triallyl isocyanurate and a vulcanizing agent, bisphenol AF.

[0006] Furthermore, the preparation method of the dustproof and waterproof automobile sealing material comprises the following steps: S1.1: Place the desired molding die in a flat-plate vulcanizer and preheat at 100-120°C for 20-25 minutes to obtain a preheated mold. Coat and secure the mixed rubber sheet with a polytetrafluoroethylene fiber sieve membrane, then assemble it into the preheated mold. The sheet is then hot-pressed in the flat-plate vulcanizer to obtain a primary vulcanized fluororubber. Remove the sheet, peel off the polytetrafluoroethylene fiber sieve membrane, and allow it to cool naturally for 20-24 hours. S1.2: Place the naturally cooled primary vulcanized fluororubber in an oven and perform secondary vulcanization at 200-230°C for 14-16 hours. After naturally cooling for 20-24 hours, continue to place it in an oven and perform tertiary vulcanization at 200-230°C for 12-13 hours to obtain a dustproof and waterproof automotive sealing material.

[0007] Furthermore, the preparation of the polytetrafluoroethylene fiber sieve membrane includes the following steps: S2.1: 80-100 parts by weight of polytetrafluoroethylene and 150-200 parts by weight of deionized water are uniformly mixed. 12-15 parts by weight of ammonium perfluoropolyether carboxylate and 6-8 parts by weight of azobisisobutylimidazoline hydrochloride are added sequentially at a stirring speed of 200-250 rpm. The mixture is then heated to 100-120°C and stirred for 2-3 hours to obtain a polytetrafluoroethylene emulsion. S2.2: Place 60-80 parts by weight of polyethylene glycol in a container, add 100-120 parts by weight of deionized water, and stir at 40-45°C and 250-300 rpm for 25-30 minutes to obtain a polyethylene glycol aqueous solution. Add the polyethylene glycol aqueous solution to the polytetrafluoroethylene emulsion prepared in step S2.1, stir evenly, and evaporate and concentrate to a solid content of 55-60%. Then, place the mixture in an ultrasonic disperser and ultrasonically disperse it at an ultrasonic frequency of 25-30 kHz for 15-20 minutes to obtain an ultra-dispersed spinning solution. S2.3: Use an electrospinning machine to electrospin the ultra-dispersed spinning solution to obtain a composite fiber membrane. Fix and clamp the two same corners of the composite fiber membrane and immerse it vertically in deionized water at 90-95°C. After soaking for 25-30 minutes, use an ultrasonic vibrator to apply vibration at a frequency of 8-10kHz to the deionized water for 4-5 minutes. Then take out the clamped composite fiber membrane and rinse it with 80-85°C deionized water for 3-4 times. Cut off the part of the composite fiber membrane that is not immersed in deionized water to obtain a polytetrafluoroethylene fiber sieve membrane.

[0008] Furthermore, the preparation of the mixed film includes the following steps: S3.1: Start the internal mixer and adjust the internal temperature to 110-120°C. Then, add 100-120 parts by weight of FFKM raw rubber into the internal mixer. Close the top plug and keep the mixture warm at 20-30 rpm for 2-3 minutes. Then, open the top plug, add 20-25 parts by weight of filler, and continue kneading at 40-60 rpm for 2-3 minutes. After draining at 140-160°C, place the mixture on a two-roll mill and roll out sheets with a thickness of 1.8-2.2 mm. After natural cooling, the raw rubber sheet is obtained. S3.2: Put 120-150 parts by weight of raw film into an open mixing mill, set the front and rear roller speed ratio to 1: (1.2-1.4), adjust the roller distance to 0.8-1mm, add 1-1.5 parts by weight of zinc stearate after the raw film is rolled and mix for 2-3 minutes, then add 0.8-1.2 parts by weight of triallyl isocyanurate and mix for 3-4 minutes, then add 2-2.5 parts by weight of vulcanizing agent bisphenol AF and make a triangle bag and mix for 8-10 minutes, then adjust the roller distance to 0.3-0.5mm for 10-12 minutes of thin passing, then adjust the roller distance to 1-1.2mm to discharge the film to obtain the mixed film.

[0009] Furthermore, the hot pressing molding in step S1.1 is specifically hot pressing molding under conditions of 60-65 MPa and 175-185° C. for 10-15 minutes.

[0010] Furthermore, the molecular weight of the polyethylene glycol in step S2.2 is 3500-4400 Da.

[0011] Furthermore, in step S2.3, the electrospinning voltage is 20-25 kV, the spinning injection propulsion rate is 0.4-0.5 mL / h, and the distance between the spinning nozzle head and the electrode roller collector is 14-16 cm.

[0012] Furthermore, in step S3.1, the filler is one or more of N990 carbon black, barium sulfate and calcium fluoride.

[0013] A dustproof and waterproof automobile sealing plugging material is prepared by the above-mentioned method for preparing the dustproof and waterproof automobile sealing plugging material.

[0014] On the other hand, the present application provides an application method of the above-mentioned dustproof and waterproof automobile sealing material. By sealing the joint surfaces of automobile mechanical parts with the dustproof and waterproof automobile sealing material, it can effectively prevent liquid and gas leakage, and prevent dust and moisture from invading the interior of the machine equipment.

[0015] The beneficial effects are: 1. The present invention prepares a polytetrafluoroethylene fiber sieve membrane with a uniform microporous structure, and then uses the polytetrafluoroethylene fiber sieve membrane to cover and fix the fluororubber mixed film so that it is tightly attached to the surface of the mixed film, and then places it in a molding mold for vulcanization molding. During the vulcanization molding process, the rubber is subjected to the pressure of the template at high temperature, and penetrates into the uniform microporous structure of the polytetrafluoroethylene fiber sieve membrane during the flow crosslinking process. After the first vulcanization and crosslinking is completed, the polytetrafluoroethylene fiber sieve membrane is peeled off. Since the polytetrafluoroethylene material has high lubricity and non-stickiness, it can stably leave a complete and clear convex structure on the surface of the first vulcanized fluororubber. After the second and third vulcanizations, micron-sized pits and micron-sized grooves are formed on the fluororubber surface, which can give the fluororubber surface superhydrophobicity and excellent self-cleaning ability, so that it can better seal the joint surfaces of automotive mechanical parts, provide effective dustproof, waterproof and sealing performance, and achieve superhydrophobic surface modification during the fluororubber vulcanization process. The process is simple, energy consumption is low, and production efficiency is high.

[0016] 2. The present invention prepares a polytetrafluoroethylene emulsion by mixing polytetrafluoroethylene, deionized water, perfluoropolyether ammonium carboxylate and azobisisobutylimidazoline hydrochloride and heating the mixture to react. The polytetrafluoroethylene emulsion and the polyethylene glycol aqueous solution are then ultrasonically mixed to fully mix the two, and then electrospun to obtain a composite fiber membrane, which is then immersed in hot water. At this time, the polyethylene glycol uniformly dispersed in the composite fiber membrane will dissolve in the hot water, thereby forming a uniform microporous structure on the surface of the polytetrafluoroethylene. The process steps are simple and the preparation conditions are mild. The obtained polytetrafluoroethylene fiber sieve membrane has few defects, a uniform microporous structure, excellent thermal stability and mechanical properties, and can better form a complete and uniform protrusion structure on the surface of the fluororubber, thereby further improving the waterproof and dustproof properties of the fluororubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of a method for preparing a dustproof and waterproof automobile sealing material used in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. Example 1

[0019] A method for preparing a dustproof and waterproof automobile sealing material comprises the following steps: S1.1: Place the desired molding die in a flat-plate vulcanizer and preheat at 100°C for 20 minutes to obtain a preheated mold. Wrap the mixed rubber sheet with a polytetrafluoroethylene fiber sieve membrane and secure it. Assemble the sheet into the preheated mold. The sheet is then placed in the flat-plate vulcanizer again and hot-pressed at 60 MPa and 175°C for 10 minutes to obtain a primary vulcanized fluororubber. Remove the sheet, peel off the polytetrafluoroethylene fiber sieve membrane, and allow it to cool naturally for 20 hours. S1.2: Place the naturally cooled primary vulcanized fluororubber in an oven and perform secondary vulcanization at 200°C for 14 hours. After naturally cooling for 20 hours, continue to place it in the oven and perform tertiary vulcanization at 200°C for 12 hours to obtain a dustproof and waterproof automotive sealing material.

[0020] The preparation of the polytetrafluoroethylene fiber sieve membrane comprises the following steps: S2.1: 80 parts by weight of polytetrafluoroethylene and 150 parts by weight of deionized water were uniformly mixed. 12 parts by weight of ammonium perfluoropolyether carboxylate and 6 parts by weight of azobisisobutylimidazoline hydrochloride were added sequentially at a stirring speed of 200 rpm. The mixture was then heated to 100°C and stirred for 2 hours to obtain a polytetrafluoroethylene emulsion. S2.2: 60 parts by weight of polyethylene glycol (3500 Da) was placed in a container, and 100 parts by weight of deionized water was added. The mixture was stirred at 40°C and 250 rpm for 25 minutes to obtain a polyethylene glycol aqueous solution. The polyethylene glycol aqueous solution was added to the polytetrafluoroethylene emulsion prepared in step S2.1. After stirring, the mixture was evaporated and concentrated to a solid content of 55%. The mixture was then placed in an ultrasonic disperser and ultrasonically dispersed at a frequency of 25 kHz for 15 minutes to obtain a superdispersed spinning solution. S2.3: Use an electrospinning machine to electrospin the ultra-dispersed spinning solution. The electrospinning voltage is 20 kV, the spinning injection propulsion rate is 0.4 mL / h, and the distance between the spinning nozzle head and the electrode roller collector is 14 cm to obtain a composite fiber membrane. Fix and clamp the two same corners of the composite fiber membrane and vertically immerse it in 90°C deionized water. After soaking for 25 minutes, use an ultrasonic vibrator to apply vibration at a frequency of 8 kHz to the deionized water for 4 minutes. Then take out the clamped composite fiber membrane, rinse it with 80°C deionized water 3 times, and cut off the part of the composite fiber membrane that is not immersed in deionized water to obtain a polytetrafluoroethylene fiber sieve membrane.

[0021] The preparation of the mixed film comprises the following steps: S3.1: Start the internal mixer and adjust the internal temperature to 110°C. Then, add 100 parts by weight of FFKM raw rubber into the internal mixer. Close the top plug and knead at 20 rpm for 2 minutes. Then, open the top plug, add 20 parts by weight of N990 carbon black, and continue kneading at 40 rpm for 2 minutes. After draining at 140°C, place the mixture on a two-roll mill and roll out a sheet with a thickness of 1.8 mm. After natural cooling, the raw rubber sheet is obtained. S3.2: Put 120 parts by weight of raw rubber sheet into an open mixing mill, set the front and rear roller speed ratio to 1:1.2, adjust the roller distance to 0.8 mm, add 1 part by weight of zinc stearate after the raw rubber sheet is rolled and mix for 2 minutes, then add 0.8 parts by weight of triallyl isocyanurate and mix for 3 minutes, then add 2 parts by weight of vulcanizing agent bisphenol AF and make a triangle package and mix for 8 minutes, then adjust the roller distance to 0.3 mm and carry out thin passing for 10 minutes, then adjust the roller distance to 1 mm to discharge the film to obtain the mixed film. Example 2

[0022] A method for preparing a dustproof and waterproof automobile sealing material comprises the following steps: S1.1: Place the desired molding die in a flat-plate vulcanizer and preheat at 100°C for 20 minutes to obtain a preheated mold. Wrap the mixed rubber sheet with a polytetrafluoroethylene fiber sieve membrane and secure it. Assemble the sheet into the preheated mold. The sheet is then placed in the flat-plate vulcanizer again and hot-pressed at 60 MPa and 175°C for 10 minutes to obtain a primary vulcanized fluororubber. Remove the sheet, peel off the polytetrafluoroethylene fiber sieve membrane, and allow it to cool naturally for 20 hours. S1.2: Place the naturally cooled primary vulcanized fluororubber in an oven and perform secondary vulcanization at 200°C for 14 hours. After naturally cooling for 20 hours, continue to place it in the oven and perform tertiary vulcanization at 200°C for 12 hours to obtain a dustproof and waterproof automotive sealing material.

[0023] The preparation of the polytetrafluoroethylene fiber sieve membrane comprises the following steps: S2.1: 100 parts by weight of polytetrafluoroethylene and 200 parts by weight of deionized water were uniformly mixed. 15 parts by weight of ammonium perfluoropolyether carboxylate and 8 parts by weight of azobisisobutylimidazoline hydrochloride were added sequentially at a stirring speed of 200 rpm. The mixture was then heated to 100°C and stirred for 2 hours to obtain a polytetrafluoroethylene emulsion. S2.2: 80 parts by weight of polyethylene glycol (3500 Da) was placed in a container, 120 parts by weight of deionized water was added, and the mixture was stirred at 40°C and 250 rpm for 25 minutes to obtain a polyethylene glycol aqueous solution. The polyethylene glycol aqueous solution was added to the polytetrafluoroethylene emulsion prepared in step S2.1, and the mixture was stirred uniformly and evaporated to a solid content of 55%. The mixture was then placed in an ultrasonic disperser and ultrasonically dispersed at a frequency of 25 kHz for 15 minutes to obtain a superdispersed spinning solution. S2.3: Use an electrospinning machine to electrospin the ultra-dispersed spinning solution. The electrospinning voltage is 20 kV, the spinning injection propulsion rate is 0.4 mL / h, and the distance between the spinning nozzle head and the electrode roller collector is 14 cm to obtain a composite fiber membrane. Fix and clamp the two same corners of the composite fiber membrane and vertically immerse it in 90°C deionized water. After soaking for 25 minutes, use an ultrasonic vibrator to apply vibration at a frequency of 8 kHz to the deionized water for 4 minutes. Then take out the clamped composite fiber membrane, rinse it with 80°C deionized water 3 times, and cut off the part of the composite fiber membrane that is not immersed in deionized water to obtain a polytetrafluoroethylene fiber sieve membrane.

[0024] The preparation of the mixed film comprises the following steps: S3.1: Start the internal mixer and adjust the internal temperature to 110°C. Then, add 120 parts by weight of FFKM raw rubber into the internal mixer. Close the top plug and knead at 20 rpm for 2 minutes. Then, open the top plug, add 25 parts by weight of barium sulfate, and continue kneading at 40 rpm for 2 minutes. After draining at 140°C, place the mixture on a two-roll mill and roll out a sheet with a thickness of 1.8 mm. After natural cooling, the raw rubber sheet is obtained. S3.2: Put 150 parts by weight of raw rubber sheet into an open mixing mill, set the front and rear roller speed ratio to 1:1.2, adjust the roller distance to 0.8 mm, add 1.5 parts by weight of zinc stearate after the raw rubber sheet is rolled and mix for 2 minutes, then add 1.2 parts by weight of triallyl isocyanurate and mix for 3 minutes, then add 2.5 parts by weight of vulcanizing agent bisphenol AF and make a triangle package and mix for 8 minutes, then adjust the roller distance to 0.3 mm for 10 minutes of thin passing, then adjust the roller distance to 1 mm to discharge the film to obtain the mixed film. Example 3

[0025] A method for preparing a dustproof and waterproof automobile sealing material comprises the following steps: S1.1: Place the desired molding die in a flat-plate vulcanizer and preheat at 120°C for 25 minutes to obtain a preheated mold. Wrap the mixed rubber sheet with a polytetrafluoroethylene fiber sieve membrane and secure it. Assemble the sheet into the preheated mold. The sheet is then placed in the flat-plate vulcanizer again and hot-pressed at 65 MPa and 185°C for 15 minutes to obtain a primary vulcanized fluororubber. Remove the sheet, peel off the polytetrafluoroethylene fiber sieve membrane, and allow it to cool naturally for 24 hours. S1.2: Place the naturally cooled primary vulcanized fluororubber in an oven and perform secondary vulcanization at 230°C for 16 hours. After naturally cooling for 24 hours, continue to place it in the oven and perform tertiary vulcanization at 230°C for 13 hours to obtain a dustproof and waterproof automotive sealing material.

[0026] The preparation of the polytetrafluoroethylene fiber sieve membrane comprises the following steps: S2.1: 80 parts by weight of polytetrafluoroethylene and 150 parts by weight of deionized water were uniformly mixed. 12 parts by weight of ammonium perfluoropolyether carboxylate and 6 parts by weight of azobisisobutylimidazoline hydrochloride were added sequentially with stirring at 250 rpm. The mixture was then heated to 120°C and stirred for 3 hours to obtain a polytetrafluoroethylene emulsion. S2.2: Place 60 parts by weight of polyethylene glycol (PEG) with a molecular weight of 4400 Da in a container, add 100 parts by weight of deionized water, and stir at 45°C and 300 rpm for 30 minutes to obtain a polyethylene glycol aqueous solution. Add the polyethylene glycol aqueous solution to the polytetrafluoroethylene emulsion prepared in step S2.1, stir evenly, and evaporate and concentrate to a solid content of 60%. Then, place the solution in an ultrasonic disperser and ultrasonically disperse it at an ultrasonic frequency of 30 kHz for 20 minutes to obtain a superdispersed spinning solution. S2.3: Use an electrospinning machine to electrospin the ultra-dispersed spinning solution. The electrospinning voltage is 25 kV, the spinning injection propulsion rate is 0.5 mL / h, and the distance between the spinning nozzle head and the electrode roller collector is 16 cm to obtain a composite fiber membrane. Fix and clamp the two same corners of the composite fiber membrane and vertically immerse it in 95°C deionized water. After soaking for 30 minutes, use an ultrasonic vibrator to apply vibration at a frequency of 10 kHz to the deionized water for 5 minutes. Then take out the clamped composite fiber membrane, rinse it with 85°C deionized water 4 times, and cut off the part of the composite fiber membrane that is not immersed in deionized water to obtain a polytetrafluoroethylene fiber sieve membrane.

[0027] The preparation of the mixed film comprises the following steps: S3.1: Start the internal mixer and adjust the internal temperature to 120°C. Then, add 100 parts by weight of FFKM raw rubber into the internal mixer. Close the top plug and knead at 30 rpm for 3 minutes. Then, open the top plug, add 20 parts by weight of calcium fluoride, and continue kneading at 60 rpm for 3 minutes. After draining at 160°C, place the mixture on a two-roll mill and roll out a sheet with a thickness of 1.8 mm. After natural cooling, the raw rubber sheet is obtained. S3.2: Put 120 parts by weight of raw rubber sheet into an open mixing mill, set the front and rear roller speed ratio to 1:1.4, adjust the roller distance to 1mm, add 1 part by weight of zinc stearate after the raw rubber sheet is rolled and mix for 3 minutes, then add 0.8 parts by weight of triallyl isocyanurate and mix for 4 minutes, then add 2 parts by weight of vulcanizing agent bisphenol AF and make a triangle package and mix for 10 minutes, then adjust the roller distance to 0.5mm for 12 minutes of thin passing, and then adjust the roller distance to 1.2mm to discharge the film to obtain the mixed film.

[0028] Comparative Example 1 A dustproof and waterproof automobile sealing material and a preparation method thereof, compared with the implementation method of Example 1, the difference is that a polytetrafluoroethylene fiber sieve membrane is used to coat the mixed film during the vulcanization molding process in step S1.1, and the remaining steps are uniformly the same as Example 1.

[0029] Dust-proof and waterproof automobile sealing plugging materials with a length, width and thickness of 10 cm×5 cm×1 cm prepared according to the embodiments 1-3 and comparative example 1 were used as samples; Contact angle test: The water contact angle of the sample was measured using a contact angle meter. The single circle tangent method was used. Ten different points were selected for measurement on each sample, and the average value was taken. The test results are shown in Table 1. Rolling angle test: A 15 μL water droplet was dropped onto the sample surface. The sample was then rotated and the angle of surface rotation as the droplet rolled down was recorded. Three parallel experiments were performed and the average value was taken. The test results are shown in Table 1. Mechanical properties test: tensile strength was tested according to GB / T528-2009. Each sample was tested 3 times, and the data were recorded and tabulated as shown in Table 2.

[0030] It can be seen from the data of Examples 1-3 and Comparative Example 1 in Table 1 that the water contact angle and rolling angle of the fluororubber surface can be greatly improved by coating the mixed rubber sheet with a polytetrafluoroethylene fiber sieve membrane and then vulcanizing and molding it, which proves that the polytetrafluoroethylene fiber sieve membrane can form micron-sized pits and micron-sized grooves on the fluororubber surface, and can give the fluororubber surface superhydrophobicity.

[0031] It can be seen from the data of Examples 1-3 and Comparative Example 1 in Table 2 that the tensile strength of the vulcanized rubber obtained by coating the mixed rubber sheet with a polytetrafluoroethylene fiber sieve membrane and then vulcanizing and molding is not much different from that obtained by direct vulcanization molding, which proves that the modification of the fluororubber surface by the polytetrafluoroethylene fiber sieve membrane does not affect the mechanical properties of the fluororubber and can maintain good mechanical properties.

[0032] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for preparing a dustproof and waterproof automobile sealing material, characterized by: The mixed rubber sheet is coated and fixed with a polytetrafluoroethylene fiber sieve membrane, then assembled into a preheated forming mold and placed in a flat vulcanizer for hot pressing. After being taken out, the polytetrafluoroethylene fiber sieve membrane and the primary vulcanized fluororubber are peeled off. The primary vulcanized fluororubber is cooled and then subjected to secondary vulcanization. After cooling again, it is subjected to tertiary vulcanization to obtain a dustproof and waterproof automotive sealing material. The polytetrafluoroethylene fiber sieve membrane is prepared by ultrasonically mixing a polytetrafluoroethylene emulsion made of polytetrafluoroethylene, deionized water, perfluoropolyether ammonium carboxylate and azobisisobutylimidazoline hydrochloride with a polyethylene glycol aqueous solution, electrospinning the emulsion, and then soaking it in hot water and ultrasonically dispersing it. The mixed rubber sheet is obtained by kneading and rolling out FFKM raw rubber into a raw rubber sheet, and then mixing it with zinc stearate, triallyl isocyanurate and vulcanizing agent bisphenol AF.

2. The method for preparing a dustproof and waterproof automobile sealing material according to claim 1, characterized in that: The following steps are involved: S1.1: Place the desired molding die in a flat-plate vulcanizer and preheat at 100-120°C for 20-25 minutes to obtain a preheated mold. Coat and secure the mixed rubber sheet with a polytetrafluoroethylene fiber sieve membrane, then assemble it into the preheated mold. The sheet is then hot-pressed in the flat-plate vulcanizer to obtain a primary vulcanized fluororubber. Remove the sheet, peel off the polytetrafluoroethylene fiber sieve membrane, and allow it to cool naturally for 20-24 hours. S1.2: Place the naturally cooled primary vulcanized fluororubber in an oven and perform secondary vulcanization at 200-230°C for 14-16 hours. After naturally cooling for 20-24 hours, continue to place it in an oven and perform tertiary vulcanization at 200-230°C for 12-13 hours to obtain a dustproof and waterproof automotive sealing material.

3. The method for preparing a dustproof and waterproof automobile sealing material according to claim 2, characterized in that: The preparation of polytetrafluoroethylene fiber sieve membrane includes the following steps: S2.1: 80-100 parts by weight of polytetrafluoroethylene and 150-200 parts by weight of deionized water are uniformly mixed. 12-15 parts by weight of ammonium perfluoropolyether carboxylate and 6-8 parts by weight of azobisisobutylimidazoline hydrochloride are added sequentially at a stirring speed of 200-250 rpm. The mixture is then heated to 100-120°C and stirred for 2-3 hours to obtain a polytetrafluoroethylene emulsion. S2.2: Place 60-80 parts by weight of polyethylene glycol in a container, add 100-120 parts by weight of deionized water, and stir at 40-45°C and 250-300 rpm for 25-30 minutes to obtain a polyethylene glycol aqueous solution. Add the polyethylene glycol aqueous solution to the polytetrafluoroethylene emulsion prepared in step S2.1, stir evenly, and evaporate and concentrate to a solid content of 55-60%. Then, place the mixture in an ultrasonic disperser and ultrasonically disperse it at an ultrasonic frequency of 25-30 kHz for 15-20 minutes to obtain an ultra-dispersed spinning solution. S2.3: Use an electrospinning machine to electrospin the ultra-dispersed spinning solution to obtain a composite fiber membrane. Fix and clamp the two same corners of the composite fiber membrane and immerse it vertically in deionized water at 90-95°C. After soaking for 25-30 minutes, use an ultrasonic vibrator to apply vibration at a frequency of 8-10kHz to the deionized water for 4-5 minutes. Then take out the clamped composite fiber membrane and rinse it with 80-85°C deionized water for 3-4 times. Cut off the part of the composite fiber membrane that is not immersed in deionized water to obtain a polytetrafluoroethylene fiber sieve membrane.

4. The method for preparing a dustproof and waterproof automobile sealing material according to claim 3, characterized in that: The preparation of the mixed film comprises the following steps: S3.1: Start the internal mixer and adjust the internal temperature to 110-120°C. Then, add 100-120 parts by weight of FFKM raw rubber into the internal mixer. Close the top plug and keep the mixture warm at 20-30 rpm for 2-3 minutes. Then, open the top plug, add 20-25 parts by weight of filler, and continue kneading at 40-60 rpm for 2-3 minutes. After draining at 140-160°C, place the mixture on a two-roll mill and roll out sheets with a thickness of 1.8-2.2 mm. After natural cooling, the raw rubber sheet is obtained. S3.2: Put 120-150 parts by weight of raw film into an open mixing mill, set the front and rear roller speed ratio to 1: (1.2-1.4), adjust the roller distance to 0.8-1mm, add 1-1.5 parts by weight of zinc stearate after the raw film is rolled and mix for 2-3 minutes, then add 0.8-1.2 parts by weight of triallyl isocyanurate and mix for 3-4 minutes, then add 2-2.5 parts by weight of vulcanizing agent bisphenol AF and make a triangle bag and mix for 8-10 minutes, then adjust the roller distance to 0.3-0.5mm for 10-12 minutes of thin passing, then adjust the roller distance to 1-1.2mm to discharge the film to obtain the mixed film.

5. The method for preparing a dustproof and waterproof automobile sealing material according to claim 2, characterized in that: The hot pressing in step S1.1 is specifically performed under conditions of 60-65 MPa and 175-185° C. for 10-15 minutes.

6. The method for preparing a dustproof and waterproof automobile sealing material according to claim 3, characterized in that: The molecular weight of polyethylene glycol in step S2.2 is 3500-4400 Da.

7. The method for preparing a dustproof and waterproof automobile sealing material according to claim 3, characterized in that: In step S2.3, the electrospinning voltage is 20-25 kV, the spinning injection propulsion rate is 0.4-0.5 mL / h, and the distance between the spinning nozzle head and the electrode roller collector is 14-16 cm.

8. The method for preparing a dustproof and waterproof automobile sealing material according to claim 4, characterized in that: In step S3.1, the filler is one or more of N990 carbon black, barium sulfate and calcium fluoride.

9. A dustproof and waterproof automobile sealing material, characterized in that: The dustproof and waterproof automobile sealing material is prepared by the preparation method of any one of claims 1 to 8.

10. Use of the dustproof and waterproof automobile sealing material according to claim 9 in automobile sealing treatment.

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