High-performance sealing gasket with self-repairing function and preparation method thereof

Abstract

The invention discloses a high-performance sealing gasket with a self-repairing function and a preparation method thereof. The sealing gasket comprises a basic sealing material, a self-repairing functional material, an inorganic filler, a cross-linking agent and other auxiliaries. The self-repairing microcapsule contains bisphenol A epoxy resin as a repairing agent and a mixture of polyamide and ester cyclic amine as a curing agent, and the diameter of the microcapsule is 50-100 microns. The high-performance sealing gasket is prepared by uniformly mixing the components at a specific temperature for a specific time, carrying out hot press molding, and carrying out secondary curing treatment. The sealing gasket has excellent sealing performance, high temperature resistance, chemical corrosion resistance and wear resistance, and also has self-repairing capability. When the sealing gasket is cracked or damaged, the repairing agent and the curing agent in the microcapsule are automatically released, the crack is filled and cured, and self-repairing is realized, so that the service life of the sealing gasket is prolonged.

Description

Technical Field

[0001] The present invention relates to the field of preparation of sealing gaskets, and more particularly to a high-performance sealing gasket with self-repairing function and a preparation method thereof. Background Art

[0002] Gaskets are widely used in various mechanical equipment, piping systems and containers to prevent leakage of liquids or gases. In industrial production, gaskets usually work in harsh environments such as high temperature, high pressure, chemical corrosion and mechanical stress, so the performance requirements of gaskets are very strict. Traditional gasket materials are mostly rubber, graphite, metal and other materials. Although these materials can provide good sealing effects under certain conditions, they often face problems such as aging, wear and fatigue during long-term use, which leads to sealing failure.

[0003] Under harsh working conditions, local damage to the gasket is inevitable. When the gasket has microcracks or slight damage, if it cannot be repaired in time, it will cause sealing failure, resulting in equipment shutdown and maintenance, and even cause safety accidents. Therefore, how to improve the gasket's damage resistance while maintaining sealing performance has become a difficult problem that the industry needs to solve urgently. Summary of the invention

[0004] In order to solve the deficiencies of the prior art, the present invention provides a high-performance sealing gasket with self-repairing function and a preparation method thereof, and the specific scheme is as follows:

[0005] A high-performance sealing gasket with self-repairing function, the sealing gasket comprises the following components in percentage by mass:

[0006] 50-70% of basic sealing material, wherein the basic sealing material is a mixture of polytetrafluoroethylene and fluororubber;

[0007] 10-30% of self-repairing functional material; the self-repairing functional material comprises self-repairing microcapsules, and the self-repairing microcapsules comprise a repairing agent and a curing agent;

[0008] 5-20% of inorganic filler; the inorganic filler is a combination of one or both of carbon nanotubes and aluminum oxide;

[0009] 1-5% cross-linking agent; the cross-linking agent is an isocyanate compound;

[0010] The rest are auxiliary agents.

[0011] Furthermore, the repair agent is bisphenol A epoxy resin, and the amount of the bisphenol A epoxy resin is 60-80% of the amount of the self-repairing microcapsules.

[0012] Furthermore, the curing agent is a mixture of polyamide and ester cyclic amine; the ratio of polyamide to ester cyclic amine is 1:1; and the amount of the curing agent is 20-40% of the amount of the microcapsule.

[0013] Furthermore, the amount of carbon nanotubes added is 3-5%, and the amount of aluminum oxide added is 10-15%.

[0014] Furthermore, the diameter of the self-repairing microcapsule is 50-100 μm.

[0015] Furthermore, the cross-linking agent is one or a mixture of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate or isophorone diisocyanate.

[0016] A method for preparing a high-performance sealing gasket with self-repairing function, the preparation method comprising the following steps:

[0017] S1. Preparation of self-healing functional materials;

[0018] S2. Put the basic sealing material, inorganic filler and self-repairing functional material into a high-speed mixer, control the temperature at 50-60°C, and stir for 30 minutes to ensure that the materials are evenly mixed; add a cross-linking agent to the above mixture and continue stirring for 10-15 minutes to ensure that the components are fully mixed;

[0019] S3, transferring the uniformly mixed material into a mold for hot pressing;

[0020] S4. After hot pressing, cool naturally to room temperature; after cooling, take the sealing gasket out of the mold and check whether there are bubbles, cracks or other defects on its surface;

[0021] S5. Put the demoulded sealing gasket into an oven for secondary curing; the curing temperature is 100° C.; the curing time is 2 hours.

[0022] Furthermore, S1 includes the following sub-steps:

[0023] S101: bisphenol A epoxy resin is selected as a repairing agent, and a mixture of polyamide and alicyclic amine is used as a curing agent; polyvinyl alcohol is selected as an emulsifier with a concentration of 1 to 2 wt%; urea-formaldehyde resin is selected as a wall material of the microcapsule;

[0024] S102: Add deionized water and 1-2 wt% polyvinyl alcohol solution to the reaction kettle; set the stirring speed to 500 rpm and maintain the temperature at 30-40° C. to completely dissolve the emulsifier; slowly add the weighed epoxy resin to the emulsified system; increase the stirring speed to 800-1000 rpm and continue stirring for 30-60 minutes to disperse the epoxy resin in the water phase to form oil droplets with a diameter of 50-100 μm;

[0025] S103: After the emulsified system is stable, slowly add the pre-mixed mixture of polyamide and alicyclic amine into the reactor; maintain the stirring speed at 800-1000 rpm for 10-15 minutes to ensure that the curing agent is evenly distributed in the liquid phase of the microcapsules;

[0026] S104: gradually adding urea-formaldehyde resin solution into the reaction kettle, maintaining the stirring speed at 500-800 rpm; heating the reaction system to 60-70° C., and the reaction time is 2-3 hours;

[0027] S105: After the polycondensation reaction is completed, the system is gradually cooled to room temperature and stirred for 30 minutes to further solidify the microcapsules; the generated microcapsule suspension is separated by vacuum filtration to obtain solid microcapsules; deionized water is used to wash 2 to 3 times to remove unreacted monomers and emulsifier residues on the surface, and the final self-healing functional material is obtained after drying and screening.

[0028] Beneficial effects:

[0029] The present invention provides a high-performance sealing gasket with self-repairing function and a preparation method thereof, which has the following advantages:

[0030] (1) By adding self-repairing functional materials to the raw materials of the gasket, the self-repairing microcapsules inside can automatically release the repair agent and curing agent to quickly fill the cracks and solidify them, greatly improving the service life and reliability of the gasket. This self-repairing function is particularly suitable for gaskets that are frequently damaged in high temperature and high pressure environments, effectively reducing equipment downtime and maintenance costs caused by gasket damage.

[0031] (2) By rationally mixing polytetrafluoroethylene, fluororubber and inorganic filler, the sealing gasket of the present invention has good sealing performance and can maintain a stable sealing effect under a wide temperature range of -20°C to 200°C and a high pressure condition of 0.5 to 5 MPa.

[0032] (3) The sealing gasket material of the present invention contains a composite structure of PTFE and fluororubber, which gives it excellent chemical corrosion resistance and can be used for a long time in corrosive media such as acids and alkalis. It is suitable for sealing applications of corrosive media in chemical production. DETAILED DESCRIPTION

[0033] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with examples. The examples are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0034] Embodiment 1:

[0035] A high-performance sealing gasket with self-repairing function, comprising the following components in percentage by mass:

[0036] Basic sealing material: 65%, the ratio of polytetrafluoroethylene to fluororubber is 1:1;

[0037] Self-healing functional material: 20%, self-healing microcapsules contain a mixture of 75% bisphenol A epoxy resin and 25% polyamide / alicyclic amine;

[0038] Inorganic fillers: 12%, of which carbon nanotubes account for 4% and alumina accounts for 8%;

[0039] Cross-linking agent: 3%, toluene diisocyanate is selected as the cross-linking agent;

[0040] Additives: the remaining 2%.

[0041] Preparation steps

[0042] Preparation of self-healing functional materials:

[0043] Add bisphenol A epoxy resin (75%) to 1-2% PVA solution, stir at 800 rpm, and stir for 60 minutes to form epoxy resin droplets with a diameter of 80 μm;

[0044] Add the mixture of polyamide and alicyclic amine (25%) and continue stirring for 10 minutes;

[0045] Add urea-formaldehyde resin solution, heat to 65°C, stir for 3 hours to complete the formation of microcapsules, cool, filter, and dry for later use.

[0046] mix:

[0047] Put the basic sealing material, inorganic filler and self-repairing functional material into a high-speed mixer, stir at a speed of 600 rpm, control the temperature at 55°C, and stir for 30 minutes;

[0048] Add the crosslinking agent toluene diisocyanate and continue stirring for 12 minutes to ensure that the materials are evenly mixed.

[0049] Thermoforming:

[0050] The mixture was poured into a mold, and the hot pressing temperature was set to 160°C, the pressure was 12 MPa, and the hot pressing time was 30 minutes;

[0051] After cooling naturally to room temperature, demould and inspect the surface quality.

[0052] Secondary curing:

[0053] The demoulded sealing gasket was placed in an oven and cured at 100°C for 2 hours to improve the mechanical strength and self-healing properties of the material.

[0054] Embodiment 2:

[0055] A high-performance sealing gasket with self-repairing function, comprising the following components in percentage by mass:

[0056] Basic sealing material: 60%, the ratio of polytetrafluoroethylene to fluororubber is 7:3;

[0057] Self-healing functional material: 25%, self-healing microcapsules contain a mixture of 70% bisphenol A epoxy resin and 30% polyamide / alicyclic amine;

[0058] Inorganic filler: 10%, carbon nanotubes 5%, alumina 5%;

[0059] Cross-linking agent: 3%, 4,4'-diphenylmethane diisocyanate is selected;

[0060] Additives: 2%.

[0061] Preparation steps

[0062] Preparation of self-healing functional materials:

[0063] 70% epoxy resin was added to the reaction kettle, and the stirring speed was 1000 rpm for 45 minutes to form microcapsules with a diameter of 60 μm;

[0064] Add the mixture of polyamide and alicyclic amine (30%) and continue stirring for 12 minutes;

[0065] Urea-formaldehyde resin was added, the temperature was raised to 70°C, stirred for 2 hours, cooled, filtered and dried to obtain self-healing microcapsules.

[0066] mix:

[0067] The base sealing material and the inorganic filler were mixed and stirred at 50°C for 30 minutes;

[0068] Add the self-healing functional material and MDI and continue stirring for 15 minutes.

[0069] Thermoforming:

[0070] The mold hot pressing temperature was set to 170°C, the pressure was 14 MPa, and the pressing time was 25 min;

[0071] Cool naturally to room temperature and then demould.

[0072] Secondary curing:

[0073] Curing was carried out at 100°C for 2 hours.

[0074] Embodiment 3:

[0075] A high-performance sealing gasket with self-repairing function, comprising the following components in percentage by mass:

[0076] Basic sealing material: 55%, the ratio of polytetrafluoroethylene to fluororubber is 2:1;

[0077] Self-healing functional material: 30%, self-healing microcapsules contain 80% bisphenol A epoxy resin and 20% polyamide / alicyclic amine mixture;

[0078] Inorganic filler: 8%, carbon nanotubes 3%, alumina 5%;

[0079] Cross-linking agent: 4%, isophorone diisocyanate is selected;

[0080] Additives: 3%.

[0081] Preparation steps

[0082] Preparation of self-healing functional materials:

[0083] In a reaction kettle, 80 wt% of epoxy resin was added, the stirring speed was 900 rpm, the stirring time was 60 minutes, and emulsion droplets with a particle size of 90 μm were formed;

[0084] Add the mixture of polyamide and alicyclic amine (20%) and continue stirring for 15 minutes;

[0085] Urea-formaldehyde resin was added, the temperature was heated to 65°C, and stirred for 3 hours to complete the preparation of microcapsules.

[0086] mix:

[0087] The basic sealing material, the inorganic filler and the self-repairing functional material were mixed at 60° C. and stirred for 30 minutes; IPDI was added and the stirring was continued for 10 minutes.

[0088] Thermoforming:

[0089] The mold temperature is 180°C, the pressure is 15MPa, and the pressing time is 30 minutes;

[0090] De-mould after natural cooling.

[0091] Secondary curing:

[0092] Curing was carried out at 100°C for 2 hours.

[0093] test

[0094] Sealing performance: test pressure is 4MPa, temperature range is **-20℃ to 200℃**;

[0095] Self-healing performance: crack width is 0.1mm and the repair time is 20 minutes at 80℃.

[0096] The self-repairing and sealing performance tests were performed on Examples 1 to 3, and the test data are as follows:

[0097]

[0098] It can be seen from the above table that the sealing performance and self-repairing performance of the sealing gasket are improved through the technical solution provided in the embodiment.

[0099] As a further improvement, the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-performance sealing gasket with self-repairing function, characterized in that: The sealing gasket comprises the following components in percentage by mass: 50-70% of basic sealing material, wherein the basic sealing material is a mixture of polytetrafluoroethylene and fluororubber; 10-30% of self-repairing functional material; the self-repairing functional material comprises self-repairing microcapsules, and the self-repairing microcapsules comprise a repairing agent and a curing agent; 5-20% of inorganic filler; the inorganic filler is a combination of one or both of carbon nanotubes and aluminum oxide; 1-5% cross-linking agent; the cross-linking agent is an isocyanate compound; The rest are auxiliary agents.

2. A high-performance sealing gasket with self-repairing function according to claim 1, characterized in that: The repair agent is bisphenol A epoxy resin, and the amount of the bisphenol A epoxy resin is 60-80% of the amount of the self-repairing microcapsule.

3. A high-performance sealing gasket with self-repairing function according to claim 1, characterized in that: The curing agent is a mixture of polyamide and ester cyclic amine; the ratio of polyamide to ester cyclic amine is 1:1; the amount of the curing agent is 20-40% of the amount of the microcapsule.

4. The high-performance sealing gasket with self-repairing function according to claim 1, characterized in that: The added amount of carbon nanotubes is 3-5%, and the added amount of aluminum oxide is 10-15%.

5. The high-performance sealing gasket with self-repairing function according to claim 1, characterized in that: The diameter of the self-healing microcapsules is 50 to 100 μm.

6. The high-performance sealing gasket with self-repairing function according to claim 1, characterized in that: The cross-linking agent is one or a mixture of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate or isophorone diisocyanate.

7. The method for preparing a high-performance sealing gasket with self-repairing function according to claims 1 to 6, characterized in that: The preparation method comprises the following steps: S1. Preparation of self-healing functional materials; S2. Put the basic sealing material, inorganic filler and self-repairing functional material into a high-speed mixer, control the temperature at 50-60°C, and stir for 30 minutes to ensure that the materials are evenly mixed; add a cross-linking agent to the above mixture and continue stirring for 10-15 minutes to ensure that the components are fully mixed; S3, transferring the uniformly mixed material into a mold for hot pressing; S4. After hot pressing, cool naturally to room temperature; after cooling, take the sealing gasket out of the mold and check whether there are bubbles, cracks or other defects on its surface; S5. Place the demoulded sealing gasket into an oven for secondary curing; the curing temperature is 100° C.; and the curing time is 2 hours.

8. The method for preparing a high-performance sealing gasket with self-repairing function according to claim 7, characterized in that: S1 includes the following sub-steps: S101: bisphenol A epoxy resin is selected as a repairing agent, and a mixture of polyamide and alicyclic amine is used as a curing agent; polyvinyl alcohol is selected as an emulsifier with a concentration of 1 to 2 wt%; urea-formaldehyde resin is selected as a wall material of the microcapsule; S102: Add deionized water and 1-2 wt% polyvinyl alcohol solution to the reaction kettle; set the stirring speed to 500 rpm and maintain the temperature at 30-40° C. to completely dissolve the emulsifier; slowly add the weighed epoxy resin to the emulsified system; increase the stirring speed to 800-1000 rpm and continue stirring for 30-60 minutes to disperse the epoxy resin in the water phase to form oil droplets with a diameter of 50-100 μm; S103: After the emulsified system is stable, slowly add the pre-mixed mixture of polyamide and alicyclic amine into the reactor; maintain the stirring speed at 800-1000 rpm for 10-15 minutes to ensure that the curing agent is evenly distributed in the liquid phase of the microcapsules; S104: gradually adding urea-formaldehyde resin solution into the reaction kettle, maintaining the stirring speed at 500-800 rpm; heating the reaction system to 60-70° C., and the reaction time is 2-3 hours; S105: After the polycondensation reaction is completed, the system is gradually cooled to room temperature and stirred for 30 minutes to further solidify the microcapsules; the generated microcapsule suspension is separated by vacuum filtration to obtain solid microcapsules; deionized water is used to wash 2 to 3 times to remove unreacted monomers and emulsifier residues on the surface, and the final self-healing functional material is obtained after drying and screening.

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