Sealing material and preparation method and application thereof

Abstract

The invention belongs to the technical field of sealing materials, and particularly relates to a sealing material and a preparation method and application thereof. The sealing material provided by the invention is prepared from the following raw materials in parts by mass: 100 parts of methyl vinyl silicone rubber, 28-42 parts of modified nano silicon dioxide, 2-4 parts of a structure control agent, 0.9-1.1 parts of a vulcanizing agent, 0.8-1.2 parts of an anti-aging agent, 0-6 parts of a foaming agent and 0-0.3 part of a foaming aid, the preparation method of the modified nano silicon dioxide comprises the following steps: mixing nano silicon dioxide, a silane coupling agent and a solvent, and refluxing to obtain the modified nano silicon dioxide. The tensile strength, the elongation at break, the temperature resistance and the aging resistance of the sealing material are improved under the combined action of the raw materials.

Description

Technical Field

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

[0002] Sealing strips are key components of airtight protective equipment and facilities in high-level biosafety laboratories, and are widely used in cabin gaps, airtight doors, airtight transfer windows, isolators, etc. Sealing strips that are damaged, deformed, or aged can easily lead to sealing leakage or failure. In mild cases, the sealing of equipment and facilities cannot meet the requirements, and in severe cases, the controlled environment of the laboratory will change, and even endanger the lives of personnel. Therefore, as an important measure to ensure sealing, the selection of sealing materials and their structural design are particularly important.

[0003] However, the sealing strip materials used in existing biosafety laboratories have problems such as easy cracking after repeated use and brittleness during use at low temperatures, resulting in greater risks to the durability and effectiveness of the seal. Summary of the invention

[0004] In view of this, the present invention provides a sealing material and a preparation method and application thereof. The sealing material provided by the present invention has good mechanical properties and low-temperature resistance, can be repeatedly used in a low-temperature environment and still maintain good sealing performance, thereby improving the durability and effectiveness of the seal.

[0005] In order to solve the above technical problems, the present invention provides a sealing material, comprising the following raw materials in parts by weight:

[0006]

[0007] The preparation method of the modified nano silicon dioxide comprises the following steps:

[0008] The nano-silicon dioxide, the silane coupling agent and the solvent are mixed and refluxed to obtain the modified nano-silicon dioxide.

[0009] Preferably, the average particle size of the nano-silicon dioxide is 8 to 12 nm;

[0010] The silane coupling agent includes 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, vinyltriethoxysilane or vinyltrimethoxysilane;

[0011] The solvent includes toluene, ethanol or n-butane.

[0012] Preferably, the mass ratio of the nano-silica to the silane coupling agent is 100:6-8.

[0013] Preferably, the reflux temperature is 100-120° C., and the reflux time is more than 10 hours.

[0014] Preferably, the structure control agent includes low molecular weight hydroxy silicone oil and hexamethyldisilazane;

[0015] The mass ratio of the low molecular weight hydroxy silicone oil to hexamethyldisilazane is 0.8-1.2:1.

[0016] Preferably, the antioxidant is an antioxidant formed by compounding a macromolecular hindered phenol antioxidant and titanium dioxide;

[0017] The vulcanizing agent includes dicumyl peroxide;

[0018] The blowing agent includes azodicarbonamide;

[0019] The foaming aid includes a urea foaming aid.

[0020] The present invention also provides a method for preparing the sealing material described in the above technical solution, comprising the following steps:

[0021] The sealing material comprises an inflatable sealing material or a foaming sealing material;

[0022] The preparation method of the inflatable sealing material comprises the following steps:

[0023] The methyl vinyl silicone rubber, modified nano silicon dioxide, a structure control agent and an anti-aging agent are first kneaded to obtain a first premixed rubber;

[0024] The first premixed rubber and the vulcanizing agent are first mixed and first kneaded, and then first molded and first vulcanized in sequence to obtain the inflatable sealing material;

[0025] The preparation method of the foaming sealing material comprises the following steps:

[0026] The methyl vinyl silicone rubber, the modified nano silicon dioxide, the structure control agent and the anti-aging agent are kneaded for the second time to obtain a second premixed rubber;

[0027] The second premixed rubber, the vulcanizing agent, the foaming agent and the foaming aid are mixed for a second time, kneaded for a second time, and then second molded and second vulcanized in sequence to obtain the foamed sealing material.

[0028] Preferably, in the first kneading process, the mass ratio of methyl vinyl silicone rubber, modified nano silicon dioxide, structure control agent and anti-aging agent is 100:38-42:2-4:0.8-1.2;

[0029] In the first mixing process, the mass ratio of methyl vinyl silicone rubber to vulcanizing agent is 100:0.9-1.1;

[0030] The first forming is a first thermoforming, the temperature of the first thermoforming is 170-180°C, the pressure is 10-15Pa, and the heat preservation and pressure holding time is 15-30min;

[0031] The first vulcanization includes a first stage vulcanization and a second stage vulcanization performed sequentially, wherein the temperature of the first stage vulcanization is 170-180° C. and the time is 30-60 min;

[0032] The temperature of the second stage vulcanization is 200-210° C., and the time is 2-4 hours.

[0033] Preferably, in the second kneading process, the mass ratio of methyl vinyl silicone rubber, modified nano silicon dioxide, structure control agent and anti-aging agent is 100:28-32:2-4:0.8-1.2;

[0034] In the second mixing process, the mass ratio of methyl vinyl silicone rubber, vulcanizing agent, foaming agent and foaming aid is 100:0.9-1.1:4-6:0.2-0.3;

[0035] The second forming is a second thermoforming, the temperature of the second thermoforming is 100-130°C, the pressure is 5-10Pa, and the heat preservation and pressure holding time is 15-30min;

[0036] The second vulcanization includes a third vulcanization and a fourth vulcanization performed sequentially, wherein the temperature of the third vulcanization is 100 to 130° C. and the time is 30 to 60 minutes;

[0037] The temperature of the fourth stage vulcanization is 150-170° C. and the time is 2-4 hours.

[0038] The present invention also provides the use of the sealing material described in the above technical solution or the sealing material prepared by the preparation method described in the above technical solution as a sealing strip.

[0039] The present invention provides a sealing material, comprising the following raw materials in parts by mass: 100 parts of methyl vinyl silicone rubber, 28-42 parts of modified nano silicon dioxide, 2-4 parts of structure control agent, 0.9-1.1 parts of vulcanizing agent, 0.8-1.2 parts of anti-aging agent, 0-6 parts of foaming agent, and 0-0.3 parts of foaming aid; the preparation method of the modified nano silicon dioxide comprises the following steps: mixing nano silicon dioxide, silane coupling agent and solvent for reflux to obtain the modified nano silicon dioxide. In the present invention, the methyl vinyl silicone rubber has excellent compression resistance and good aging resistance, solvent resistance and high-pressure steam resistance, and the methyl vinyl silicone rubber is used as the main material of the sealing material to improve the aging resistance of the sealing material. In the present invention, the modified nano silicon dioxide has a large specific surface area, and a large number of active groups contained on the surface can be firmly combined with the rubber matrix molecular chain, and the formed network structure can improve the strength, hardness and wear resistance of the sealing material; on the other hand, the modified nano silicon dioxide can improve the morphological stability of the rubber, slow down the aging process of the rubber, and extend the service life of the sealing material. The invention improves the tensile strength, elongation at break, temperature resistance and anti-aging performance of the sealing material under the joint action of various raw materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of the process for preparing modified nano-silicon dioxide;

[0041] Figure 2 The inflatable sealed airbag prepared in Example 1 is stretched and broken at room temperature (25°C) and -20°C respectively;

[0042] Figure 3 The actual pictures of the inflatable sealed airbag prepared in Example 1 before and after being placed at -25°C for 24 hours;

[0043] Figure 4 This is a physical picture of the inflatable sealed airbag prepared in Example 1 after UV aging and ozone aging;

[0044] Figure 5 The actual pictures of the foamed sealed airbag prepared in Example 2 after being stretched and broken at room temperature (25°C) and -20°C respectively;

[0045] Figure 6 The actual pictures of the foaming sealing material prepared in Example 2 before and after being placed at -25°C for 24 hours;

[0046] Figure 7 This is a physical picture of the foaming sealing material prepared in Example 2 after UV aging and ozone aging;

[0047] Figure 8 This is a SEM image of the foamed sealing material prepared in Example 2;

[0048] Fig. 9 It is an overall schematic diagram of the inflatable sealing strip;

[0049] Fig.10 It is a partial schematic diagram of an inflatable sealing strip;

[0050] Fig.11 is a schematic cross-sectional view of an inflatable sealing strip;

[0051] Fig.12 It is a schematic diagram of the non-working state of the inflatable sealing strip;

[0052] Fig.13 It is a schematic diagram of the working state of the inflatable sealing strip;

[0053] Figures 9 to 13 In the figure: 100 is an inflatable sealing strip; 200 is a door body; 201 is a strip installation groove; 300 is a door frame; 1 is an annular airbag; 2 is an inner ring surface; 21 is a bottom surface; 22 is a side surface; 3 is an arc surface; 4 is a sealing protrusion; 5 is a hollow air cavity; 6 is an inflation nozzle; 7 is a plane; 8 is the highest point; 9 is an anti-slip ridge. DETAILED DESCRIPTION

[0054] The present invention provides a sealing material, comprising the following raw materials in parts by weight:

[0055]

[0056]

[0057] The preparation method of the modified nano silicon dioxide comprises the following steps:

[0058] The nano-silicon dioxide, the silane coupling agent and the solvent are mixed and refluxed to obtain the modified nano-silicon dioxide.

[0059] The raw materials for preparing the sealing material provided by the present invention include 100 parts of methyl vinyl silicone rubber. In the present invention, the molar content of vinyl in the methyl vinyl silicone rubber is preferably 0.05-0.5 mol%, and more preferably 0.1-0.3 mol%. Silicone rubber is a high molecular straight chain polysiloxane with -Si-O-Si- as the main chain. Since the main chain of silicon oxygen has special properties such as high bond energy and low unsaturation, silicone rubber has outstanding properties such as high and low temperature resistance, ozone resistance, corrosion resistance, electrical insulation and air permeability. Among them, methyl vinyl silicone rubber is a polymethylsiloxane with a certain amount of vinyl grafted on the main chain, which can be prepared by heat shrinkage, hydrolysis, cracking and polymerization of chlorosilane. Methyl vinyl silicone rubber has a unique semi-organic and semi-inorganic structure, can be used in a temperature range of -50 to 250°C, has excellent compression resistance, and has good aging resistance, solvent resistance and high-pressure steam resistance.

[0060] Based on the mass fraction of methyl vinyl silicone rubber, the raw materials for preparing the sealing material provided by the present invention include 28 to 42 parts of modified nano-silica, preferably 30 or 40 parts. In the present invention, the preparation method of the modified nano-silica includes the following steps: mixing nano-silica, a silane coupling agent and a solvent for reflux to obtain the modified nano-silica. In the present invention, the average particle size of the nano-silica is preferably 8 to 12 nm, more preferably 10 nm. In the present invention, the silane coupling agent preferably includes 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane (E86E), vinyltriethoxysilane or vinyltrimethoxysilane, more preferably 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane. In the present invention, the solvent preferably includes toluene, ethanol or n-butane, more preferably ethanol. In the present invention, the ethanol is preferably anhydrous ethanol. In the present invention, the mass ratio of the nano-silica to the silane coupling agent is preferably 100:6-8, more preferably 100:7.

[0061] In the present invention, the mixing is preferably carried out under ultrasonic conditions. The present invention has no special requirements for the ultrasound, as long as it can be mixed evenly. In the present invention, the reflux temperature is preferably 100-120°C, more preferably 110-115°C; the reflux time is preferably more than 10 hours, more preferably 12-15 hours. The present invention preferably uses an oil bath to ensure the reflux temperature.

[0062] In the present invention, the reflux preferably further comprises:

[0063] The refluxed system is cooled and then centrifuged to obtain a solid;

[0064] The solid is washed and then dried to obtain the modified nano-silica.

[0065] In the present invention, the temperature of the system after cooling is preferably 20 to 35°C, more preferably 25 to 30°C. The present invention has no special requirements for the cooling method, as long as the required temperature can be reached. The present invention has no special requirements for the centrifugation, as long as solid-liquid separation can be achieved. In the present invention, the washing solvent is preferably anhydrous ethanol, and the number of washings is preferably 2 to 4 times, more preferably 3 times. The present invention has no special requirements for the drying, as long as the solvent on the surface can be removed.

[0066] The present invention grafts active groups (silane coupling agents) onto the surface of nano-silicon dioxide particles through a specific process, so that the nano-particles are bonded to the molecules in the rubber matrix, reducing the agglomeration effect of the nano-particles, improving the dispersion uniformity of the nano-particles in the matrix, and making the nano-silicon dioxide particles achieve better reinforcement, thereby further improving the strength of the sealing material.

[0067] Figure 1 Schematic diagram of the process for preparing modified nano-silica.

[0068] In the present invention, the modified nano-silicon dioxide can not only improve the high and low temperature tensile strength of silicone rubber, but also enhance its heat aging resistance and sealing performance. The modified nano-silicon dioxide has a large specific surface area. On the one hand, a large number of active groups contained on the surface of the modified nano-silicon dioxide particles are firmly combined with the rubber matrix molecular chain to form a network structure that can improve the material strength, hardness and wear resistance. On the other hand, the addition of silicon dioxide particles can improve the morphological stability of rubber, slow down the aging process of rubber, and extend the service life.

[0069] Based on the mass fraction of methyl vinyl silicone rubber, the raw materials for preparing the sealing material provided by the present invention include 2 to 4 parts of structure control agent, preferably 3 parts. In the present invention, the structure control agent preferably includes low molecular weight hydroxy silicone oil and hexamethyldisilazane; the molecular formula of the low molecular weight hydroxy silicone oil is preferably HOSi(CH3)2O[Si(CH3)2O]nSi(CH3)2OH, wherein n is preferably 5 to 20; the mass ratio of the low molecular weight hydroxy silicone oil to hexamethyldisilazane is preferably 0.8 to 1.2:1, more preferably 1:1. In the present invention, the structure control agent is an organic silane containing hydroxyl groups, which can undergo a condensation reaction with the hydroxyl groups on the surface of modified nano-silica, weaken the interaction between nano-silica and silicone rubber molecules, prevent the material from producing structuring phenomena, and enhance the durability of the material.

[0070] Based on the mass fraction of methyl vinyl silicone rubber, the raw material for preparing the sealing material provided by the present invention includes 0.9 to 1.1 parts of a vulcanizing agent, preferably 1 part. In the present invention, the vulcanizing agent preferably includes dicumyl peroxide (DCP).

[0071] Based on the mass fraction of methyl vinyl silicone rubber, the raw materials for preparing the sealing material provided by the present invention include 0.8 to 1.2 parts of antioxidant, preferably 1 part. In the present invention, the antioxidant is preferably an antioxidant formed by compounding a macromolecular hindered phenol antioxidant and titanium dioxide; in the present invention, the average particle size of the titanium dioxide is preferably 200 to 500 nm, more preferably 300 to 400 nm; the mass ratio of the macromolecular hindered phenol antioxidant to titanium dioxide is preferably 37.5 to 50:1, more preferably 40 to 50:1.

[0072] In the present invention, the anti-aging agent can improve the temperature resistance and thermal oxygen aging resistance of the rubber against light, heat, oxygen and ultraviolet factors in the use environment. In the ultraviolet light region (200-400nm), it can effectively shield most of the ultraviolet light to improve the light aging resistance of the rubber material and extend the service life of the sealing material.

[0073] Based on the mass fraction of methyl vinyl silicone rubber, the raw material for preparing the sealing material provided by the present invention includes 0 to 6 parts of a foaming agent, preferably 4 to 6 parts, and more preferably 5 parts. In the present invention, the foaming agent preferably includes azodicarbonamide (AC).

[0074] Based on the mass fraction of methyl vinyl silicone rubber, the raw material for preparing the sealing material provided by the present invention includes 0 to 0.3 parts of a foaming aid, preferably 0.2 to 0.3 parts, and more preferably 0.24 to 0.26 parts. In the present invention, the foaming aid preferably includes a urea foaming aid. In the present invention, the urea foaming aid is preferably urea or ethanolamine.

[0075] In the present invention, the sealing material includes an inflatable sealing material or a foaming sealing material;

[0076] In the present invention, the preparation method of the inflatable sealing material comprises the following steps:

[0077] The methyl vinyl silicone rubber, modified nano silicon dioxide, a structure control agent and an anti-aging agent are first kneaded to obtain a first premixed rubber;

[0078] The first premixed rubber and the vulcanizing agent are first mixed and first kneaded, and then first molded and first vulcanized in sequence to obtain the inflatable sealing material.

[0079] The present invention performs a first kneading of methyl vinyl silicone rubber, modified nano silicon dioxide, a structure control agent and an anti-aging agent to obtain a first premixed rubber. The present invention preferably adds the methyl vinyl silicone rubber into a preheated kneading machine before the first kneading to knead and break the gel, and then adds the modified nano silicon dioxide in batches. The present invention has no special requirements for the kneading and breaking the gel, and the conventional method in the art can be used. In the present invention, the batches of adding the modified nano silicon dioxide in batches are preferably 2 to 3 times.

[0080] In the present invention, the mass ratio of methyl vinyl silicone rubber, modified nano-silica, structure control agent and anti-aging agent in the first kneading process is preferably 100:38-42:2-4:0.8-1.2, more preferably 100:40:3:1. In the present invention, the first kneading time is preferably more than 1 hour, more preferably 2-3 hours.

[0081] After obtaining the first premixed rubber, the present invention first mixes the first premixed rubber and the vulcanizing agent for first mixing, and then sequentially performs first molding and first vulcanization to obtain the inflatable sealing material. In the present invention, the mass ratio of methyl vinyl silicone rubber to the vulcanizing agent during the first mixing is preferably 100:0.9-1.1, more preferably 100:1. The present invention has no special requirements for the first mixing, and the conventional method in the art can be used.

[0082] In the present invention, the first forming is the first thermoforming, and the temperature of the first thermoforming is preferably 170-180°C, more preferably 175-178°C; the pressure of the first thermoforming is preferably 10-15Pa, more preferably 12-15Pa, and the heat preservation and pressure holding time of the first thermoforming is preferably 15-30min, more preferably 20-25min.

[0083] In the present invention, the first vulcanization preferably includes a first vulcanization and a second vulcanization performed sequentially, the temperature of the first vulcanization is preferably 170-180°C, more preferably 175-178°C; the time of the first vulcanization is preferably 30-60min, more preferably 40-50min; the temperature of the second vulcanization is preferably 200-210°C, more preferably 205-208°C; the time of the second vulcanization is preferably 2-4h, more preferably 2.5-3.5h. The present invention preferably performs the first vulcanization in a vacuum oven. The purpose of the second vulcanization in the present invention is to further crosslink the rubber material and improve the mechanical properties and permanent deformation properties of the material.

[0084] In the present invention, the first vulcanization preferably further comprises: preparing a sample and sealing the port of the first vulcanized product to obtain an inflatable sealed airbag. In the present invention, the use temperature of the inflatable sealed airbag is preferably -50 to 250°C.

[0085] In the present invention, the preparation method of the foaming sealing material comprises the following steps:

[0086] The methyl vinyl silicone rubber, the modified nano silicon dioxide, the structure control agent and the anti-aging agent are kneaded for the second time to obtain a second premixed rubber;

[0087] The second premixed rubber, the vulcanizing agent, the foaming agent and the foaming aid are mixed for a second time, kneaded for a second time, and then second molded and second vulcanized in sequence to obtain the foamed sealing material.

[0088] In the present invention, methyl vinyl silicone rubber, modified nano silica, structure control agent and anti-aging agent are subjected to a second kneading to obtain a second premixed rubber. In the present invention, the mass ratio of methyl vinyl silicone rubber, modified nano silica, structure control agent and anti-aging agent in the second kneading process is preferably 100:28-32:2-4:0.8-1.2, and more preferably 100:30:3:1. In the present invention, the time of the second kneading is preferably more than 1 hour, and more preferably 2-3 hours.

[0089] After obtaining the second premixed rubber, the present invention performs a second mixing of the second premixed rubber, the vulcanizing agent, the foaming agent and the foaming aid, and then performs a second molding and a second vulcanization in sequence to obtain the foamed sealing material. In the present invention, the mass ratio of the methyl vinyl silicone rubber, the vulcanizing agent, the foaming agent and the foaming aid in the second mixing process is preferably 100:0.9-1.1:4-6:0.2-0.3, and more preferably 100:1:5:0.25. The present invention has no special requirements for the second mixing, and the conventional method in the art can be used.

[0090] In the present invention, the second molding is preferably the second thermoforming, the temperature of the second thermoforming is preferably 100-130°C, more preferably 110-120°C; the pressure of the second thermoforming is preferably 5-10Pa, more preferably 7-10Pa, and the heat preservation and pressure holding time of the second thermoforming is preferably 15-30min, more preferably 20-25min.

[0091] In the present invention, the second vulcanization preferably includes a third vulcanization and a fourth vulcanization performed sequentially, the temperature of the third vulcanization is preferably 100-130°C, more preferably 110-120°C; the time of the third vulcanization is preferably 30-60min, more preferably 40-50min; the temperature of the fourth vulcanization is preferably 150-170°C, more preferably 160-165°C; the time of the fourth vulcanization is preferably 2-4h, more preferably 2.5-3h. The present invention preferably performs the second vulcanization in a vacuum oven, and the second vulcanization is preferably two-stage vulcanization.

[0092] In the present invention, the foaming sealing material is a mechanically pressed tight sealing strip.

[0093] The present invention also provides the use of the sealing material described in the above technical solution or the sealing material prepared by the preparation method described in the above technical solution as a sealing strip. In the present invention, the sealing strip is preferably an inflatable sealing strip, and the inflatable sealing strip preferably includes an annular airbag, the annular airbag includes an inner ring surface and an outer ring surface, the outer ring surface includes a bendable arc surface and a sealing protrusion arranged at the center of the outer surface of the arc surface, and the two sides of the arc surface are respectively connected to the two sides of the inner ring surface to form an annular hollow air cavity between the inner ring surface and the outer ring surface; and also includes an inflation nozzle connected to the annular airbag, the inflation nozzle can inflate the hollow air cavity to push the arc surface and the sealing protrusion outward from the annular airbag. As a specific embodiment of the present invention, the outer end surface of the sealing protrusion is preferably a plane; the inner annular surface includes a bottom surface and side surfaces respectively connected to the two sides of the bottom surface, and the two sides of the arc surface are respectively connected to the two side surfaces; the outer surfaces of the two side surfaces are respectively provided with anti-slip ridges; the anti-slip ridges are triangular ridges with the tips facing the outsides of the side surfaces, and the triangular ridges are arranged on the side surfaces close to the bottom surface; the anti-slip ridges, the inner annular surface, the arc surface and the sealing protrusion are integrally formed; the thickness of the inner annular surface and the arc surface is the same, and the thickness is 1mm~4mm; the inflation pressure range of the annular airbag is 0.2MPa~0.5MPa.

[0094] In the present invention, the inflatable sealing strip is mainly used and installed on the door body. The outer ring surface adopts a structure of an arc surface and a sealing protrusion, which can increase the deformation stroke to meet the gap between the door body and the door frame. At the same time, the curvature of the arc surface is small, the deformation amount after inflation is small, the bending is less, and the stress concentration is small, which is beneficial to improve the service life of the inflatable sealing strip and can solve the problems of poor wear resistance of existing inflatable sealing strips and easy cracking after repeated use.

[0095] As a specific embodiment of the present invention, the inflatable sealing strip 100 includes an annular airbag 1 and an inflation nozzle 6. The annular airbag 1 includes an inner annular surface 2 and an outer annular surface. The outer annular surface includes a bendable arc surface 3 and a sealing protrusion 4 arranged at the center of the outer surface of the arc surface 3. The two sides of the arc surface 3 are respectively connected to the two sides of the inner annular surface 2 to form an annular hollow air cavity 5 between the inner annular surface 2 and the outer annular surface; the inflation nozzle 6 is connected to the annular airbag 1, and the inflation nozzle 6 can inflate the hollow air cavity 5 to push the arc surface 3 and the sealing protrusion 4 to the outside of the annular airbag 1, so that the sealing protrusion 4 and the corresponding sealing member achieve contact sealing. The above-mentioned inflatable sealing strip 100 is mainly used and installed on the door body. The outer ring surface adopts the structure of arc surface 3 plus sealing protrusion 4, which can increase the deformation stroke to meet the gap between the door body and the door frame. At the same time, the curvature of the arc surface 3 is preferably π, that is, the arc shape of the arc surface 3 is a semicircle. After inflation, the deformation is small, the bending is less, and the stress concentration is small, which is beneficial to improve the service life of the inflatable sealing strip 100 and can solve the problems of poor wear resistance and easy cracking of the existing inflatable sealing strips after repeated use.

[0096] In this embodiment, the outer end surface of the sealing protrusion 4 is preferably a plane 7. The plane structure can increase the contact area between the sealing protrusion 4 and the corresponding sealing member, thereby improving the sealing performance. Specifically, the plane 7 can be circular or polygonal (such as rectangular, regular hexagonal, etc.).

[0097] In this embodiment, the inner annular surface 2 includes a bottom surface 21 and side surfaces 22 respectively connected to two sides of the bottom surface 21 , and two sides of the arc surface 3 are respectively connected to the two side surfaces 22 .

[0098] In this embodiment, the outer surfaces of the two side surfaces 22 are respectively provided with anti-skid ridges 9. The anti-skid ridges 9 are preferably triangular ridges with the tip facing the outside of the side surface 22, and the triangular ridges are arranged at a position close to the bottom surface 21 of the side surface 22. It should be noted that the triangular ridges are annular ridges arranged along the annular airbag 1 as a whole. As a preferred solution, each side surface 22 is provided with multiple triangular ridges at a position close to the bottom surface 21.

[0099] As a specific implementation of the present invention, the anti-skid ridge 9, the inner ring surface 2, the arc surface 3 and the sealing protrusion 4 are integrally formed of rubber material. Figures 11 to 13 The shape structure of any cross section of the annular airbag 1 is hollow, and the two side surfaces 22 are parallel and symmetrically arranged on both sides of the bottom surface 21. In the natural state, the two side surfaces 22 are as follows Fig.11 and Fig.12 The arc surface 3 is perpendicular to the bottom surface 21; accordingly, the arc surface 3 is a symmetrical structure with the symmetry axis of the two side surfaces 22 as the center line, and the center line is the central axis of the sealing protrusion 4. Preferably, the thickness of the inner ring surface 2 and the arc surface 3 is uniform and the same, and the thickness is 1mm to 4mm.

[0100] Furthermore, if Fig.11 and Fig.12 The figures shown are schematic diagrams of the annular airbag 1 in a non-working state. At this time, when the arc surface 3 is completely recessed in the hollow air cavity 5, the edges on both sides of the arc surface 3 are bent and convex. At this time, the preferred plane 7 is flush with the highest point 8 on the outer surface of the edges on both sides of the arc surface 3. This design can further ensure that the deformation stroke of the outer annular surface meets the gap between the door body and the door frame.

[0101] As a preferred solution, the annular airbag 1 of this embodiment preferably uses methyl vinyl silicone rubber. At the same time, the preferred material hardness range is 60 degrees to 70 degrees Shore A; the material tensile strength range is 3.0Mpa to 8.0Mpa; the material elongation at break range is 300% to 500%. The material performance decreases by ≤10% at -20°C. After UV aging test and ozone aging test, there is no obvious yellowing or cracking on the surface of the annular airbag 1.

[0102] The following takes the installation of the inflatable sealing strip 100 in the strip installation groove 201 of the door body 200 as an example to illustrate the use principle of the inflatable sealing strip 100.

[0103] When the door body 200 is closed and needs to be sealed, compressed air of a certain pressure is filled into the hollow air cavity 5 of the annular airbag 1 through the inflation nozzle 6 from an external air source. The compressed air applies pressure to the hollow air cavity 5, so that the annular airbag 1 is compressed and expands in all directions. Among them, the arc surface 3 of the outer ring surface switches from a concave state to a convex state and extends outward. The height of the sealing protrusion 4 in the middle of the arc surface 3 increases, so that the plane 7 of the sealing protrusion 4 directly contacts and seals with the door frame 300. The inflatable sealing strip 100 fills all gaps between the strip installation groove 201 and the door frame 300 based on the excellent elasticity of the rubber material (at this time, the two side surfaces 22 and the bottom surface 21 are in contact with the groove on three sides), thereby achieving the sealing of the door body 200 and the door frame 300.

[0104] Among them, the anti-skid ridge 9 at the bottom of the side 22 can further increase the friction between the inflatable sealing strip 100 and the inner wall of the strip installation groove 201, preventing the inflatable sealing strip 100 from slipping out of the door body groove during inflation and retraction.

[0105] The specific dimensions of the inflatable sealing rubber strip 100, such as the wall thickness, width, height, and width of the sealing protrusion on the outer ring surface, can be designed according to the actual dimensions of the rubber strip installation groove 201. Specifically, the width dimension of the annular airbag 1 (i.e., the distance between the outer surfaces of the two side surfaces 22) generally ranges from 10mm to 30mm, the height dimension (i.e., the convex direction of the sealing protrusion 4, which generally refers to the height of the annular airbag 1 when the arc surface 3 is in an outward convex state, and is the distance between the end surface of the sealing protrusion 4 and the outer surface of the bottom surface 21) generally ranges from 10mm to 30mm, and the width dimension of the sealing protrusion 4 (the width direction is consistent with the width dimension direction of the annular airbag 1) generally ranges from 4mm to 17mm.

[0106] In this embodiment, the inflation pressure of the inflatable sealing strip 100 in the preferred working state is in the range of 0.2 MPa to 0.5 MPa, and the normal operating temperature range is -50°C to 250°C.

[0107] When the door body 200 needs to be opened again, the inflatable sealing strip 100 can be vented through the inflation nozzle 6, and the elastic force of the high-performance rubber material can be used to restore the original state, and the arc surface 3 of the inflatable sealing strip 100 is completely concave in the hollow air cavity 5.

[0108] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0109] Example 1

[0110] 100 g of nano-silica with an average particle size of 10 nm was dissolved in toluene after dehydration and 7 g of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane (E86E) was uniformly dispersed under ultrasonic conditions; after refluxing at 110° C. (oil bath) for 12 h, it was cooled to 30° C. and centrifuged; the solid obtained by centrifugation was washed 3 times with anhydrous ethanol and then dried to obtain modified nano-silica;

[0111] 100 g of methyl vinyl silicone rubber (the molar content of vinyl is 0.1 mol%) is added to a preheated kneader for kneading and breaking the rubber, 40 g of modified nano-silica is added in 3 batches, and 3 g of structure control agent (low molecular weight hydroxy silicone oil and hexamethyldisilazane in a mass ratio of 1:1, the molecular formula of the low molecular weight hydroxy silicone oil is HOSi(CH3)2O[Si(CH3)2O]nSi(CH3)2OH, wherein n is 10) and 1 g of antioxidant (anti-aging agent formed by compounding macromolecular hindered phenol antioxidant and titanium dioxide, wherein the average particle size of titanium dioxide is 350 nm; the mass ratio of macromolecular hindered phenol antioxidant to titanium dioxide is 40:1) is added at the same time, and kneading is continued for 3 hours to obtain a premixed rubber;

[0112] The premixed rubber and 1g of the vulcanizing agent (diisopropylbenzene oxide) are mixed and placed in an open mill for the first mixing. The product after the first mixing is kept at 175°C and 10MPa pressure for 25 minutes for the first thermoforming, and then placed in a vacuum oven for vulcanization at 175°C for 40 minutes and then at 200°C for 3 hours; the vulcanized product is sampled and the port is sealed to obtain an inflatable sealed airbag.

[0113] Example 2

[0114] Modified nano-silicon dioxide was prepared according to the method of Example 1;

[0115] A silicone rubber premix was prepared according to the method of Example 1, except that the amount of modified nano-silicon dioxide was adjusted from 40 g to 30 g;

[0116] The premixed rubber was placed in an open mill and 1g of a vulcanizing agent (diisopropylbenzene oxide), 5g of a foaming agent (azodicarbonamide) and 0.25g of a foaming aid (urea) were added for the second mixing. The product after the second mixing was kept at 110°C and 5MPa pressure for 20min for the second thermoforming, and then placed in a vacuum oven for vulcanization at 120°C for 40min and then at 160°C for 3h to obtain a foamed sealing material.

[0117] The properties of the sealing materials prepared in Example 1 and Example 2 are shown in Table 1.

[0118] Table 1 Properties of the sealing materials prepared in Examples 1 and 2

[0119]

[0120]

[0121] As can be seen from Table 1, from the test results of tensile strength and elongation at break of the sealing material at room temperature and -20°C, it can be seen that, relative to the mechanical properties at room temperature, the tensile strength of the inflatable sealed airbag prepared in Example 1 at -20°C increased from 6.8MPa to 7.9MPa, while the elongation at break decreased from 460% to 423%, and the performance decreased by ≤20%. The inflatable sealed airbag prepared in Example 1 was stretched at room temperature (25°C) and -20°C, and the actual picture after stretching and breaking is as shown in the figure below. Figure 2 After the inflatable sealed airbag material prepared in Example 1 was placed at -25°C for 24 hours, no color change or cracking occurred on the surface of the sample. Figure 3 The following are the actual pictures of the inflatable sealed airbag before and after being placed at -25℃ for 24 hours. Figure 2 , 3 It can be seen that the inflatable sealing material prepared in Example 1 has good mechanical properties and low-temperature resistant mechanical properties.

[0122] The inflatable sealing material prepared in Example 1 was subjected to UV aging and ozone aging tests to test the mechanical properties of the material. The UV aging test was performed using a UVA-340 lamp for 8 h, and the ozone aging test was performed at a temperature of 40±2°C and an ozone volume fraction of (50±5)×10 -8 The results were shown in Table 2 after exposure to ambient conditions for 72 h. Figure 4 This is a physical picture of the inflatable sealing material after UV aging.

[0123] Table 2 Mechanical properties of the inflatable sealing material prepared in Example 1 before and after UV and ozone aging

[0124]

[0125] Combining Table 2 and Figure 4 It can be seen that after the modified silicone rubber material suitable for inflatable sealing airbags prepared in Example 1 was subjected to UV aging test and ozone aging test, no obvious yellowing or cracking occurred on the surface of the sample; from the test results of tensile strength and elongation at break, there was no significant decrease in the tensile strength and elongation at break of the material before and after aging, which indicates that the material has good resistance to UV aging and ozone aging.

[0126] As can be seen from Table 1, from the tensile strength and elongation at break test results of the sealing material at room temperature and -20°C, it can be seen that, relative to the mechanical properties at room temperature, the tensile strength of the foam sealing material prepared in Example 2 at -20°C increased from 1.7MPa to 2.0MPa, while the elongation at break decreased from 404% to 370%. The foam sealing airbag prepared in Example 2 was stretched at room temperature (25°C) and -20°C, and the actual picture after stretching and breaking is as shown in the figure below. Figure 5 After the foam sealing material prepared in Example 2 was placed at -25°C for 24 hours, no color change or cracking occurred on the surface of the sample. Figure 6 The following are the actual pictures of the foam sealing material before and after being placed at -25℃ for 24 hours. Figure 5 , 6 It can be seen that the foamed sealing material prepared in Example 2 has good mechanical properties and low-temperature resistant mechanical properties.

[0127] The foam sealing material prepared in Example 2 was subjected to UV aging and ozone aging tests to test the mechanical properties of the material. The UV aging test was performed using a UVA-340 lamp for 8 h, and the ozone aging test was performed at a temperature of 40±2°C and an ozone volume fraction of (50±5)×10 -8 The results were shown in Table 3 after exposure to ambient conditions for 72 h. Figure 7 This is a physical picture of the foam sealing material after UV aging and ozone aging.

[0128] Table 3 Mechanical properties of the foam sealing material prepared in Example 2 before and after UV and ozone aging

[0129]

[0130] Combining Table 3 and Figure 7 It can be seen that after the UV aging test and the ozone aging test, the foaming sealing material prepared in Example 2 did not show obvious yellowing or cracking on the surface of the sample; from the test results of tensile strength and elongation at break, the tensile strength and elongation at break of the material after aging did not show a significant decrease compared with those before aging, which shows that the material has good resistance to UV aging and ozone aging.

[0131] The foaming sealing material prepared in Example 2 was examined by scanning electron microscopy to obtain a SEM image, as shown in FIG. Figure 8 As shown. Figure 8 It can be seen that the bubbles in the foamed sealing material are round or oval in shape and have complete bubble walls, indicating that the foamed rubber material is mainly a closed-cell structure.

[0132] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A sealing material, characterized in that: The invention comprises the following raw materials in parts by weight: The preparation method of the modified nano silicon dioxide comprises the following steps: The nano-silicon dioxide, the silane coupling agent and the solvent are mixed and refluxed to obtain the modified nano-silicon dioxide.

2. The sealing material according to claim 1, characterized in that: The average particle size of the nano silicon dioxide is 8 to 12 nm; The silane coupling agent includes 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, vinyltriethoxysilane or vinyltrimethoxysilane; The solvent includes toluene, ethanol or n-butane.

3. The sealing material according to claim 1 or 2, characterized in that: The mass ratio of the nano silicon dioxide to the silane coupling agent is 100:6-8.

4. The sealing material according to claim 1 or 2, characterized in that: The reflux temperature is 100-120° C., and the reflux time is more than 10 hours.

5. The sealing material according to claim 1, characterized in that: The structure control agent includes low molecular weight hydroxy silicone oil and hexamethyldisilazane; The mass ratio of the low molecular weight hydroxy silicone oil to hexamethyldisilazane is 0.8-1.2:

1.

6. The sealing material according to claim 1, characterized in that: The anti-aging agent is a compound of a macromolecular hindered phenol antioxidant and titanium dioxide; The vulcanizing agent includes dicumyl peroxide; The blowing agent includes azodicarbonamide; The foaming aid includes a urea foaming aid.

7. The method for preparing the sealing material according to any one of claims 1 to 6, characterized in that: The following steps are involved: The sealing material comprises an inflatable sealing material or a foaming sealing material; The preparation method of the inflatable sealing material comprises the following steps: The methyl vinyl silicone rubber, modified nano silicon dioxide, a structure control agent and an anti-aging agent are first kneaded to obtain a first premixed rubber; The first premixed rubber and the vulcanizing agent are first mixed and first kneaded, and then first molded and first vulcanized in sequence to obtain the inflatable sealing material; The preparation method of the foaming sealing material comprises the following steps: The methyl vinyl silicone rubber, the modified nano silicon dioxide, the structure control agent and the anti-aging agent are kneaded for the second time to obtain a second premixed rubber; The second premixed rubber, the vulcanizing agent, the foaming agent and the foaming aid are mixed for a second time, kneaded for a second time, and then second molded and second vulcanized in sequence to obtain the foamed sealing material.

8. The preparation method according to claim 7, characterized in that: In the first kneading process, the mass ratio of methyl vinyl silicone rubber, modified nano silicon dioxide, structure control agent and anti-aging agent is 100:38-42:2-4:0.8-1.2; In the first mixing process, the mass ratio of methyl vinyl silicone rubber to vulcanizing agent is 100:0.9-1.1; The first forming is a first thermoforming, the temperature of the first thermoforming is 170-180°C, the pressure is 10-15Pa, and the heat preservation and pressure holding time is 15-30min; The first vulcanization includes a first stage vulcanization and a second stage vulcanization performed sequentially, wherein the temperature of the first stage vulcanization is 170-180° C. and the time is 30-60 min; The temperature of the second stage vulcanization is 200-210° C., and the time is 2-4 hours.

9. The preparation method according to claim 7, characterized in that: In the second kneading process, the mass ratio of methyl vinyl silicone rubber, modified nano silicon dioxide, structure control agent and anti-aging agent is 100:28-32:2-4:0.8-1.2; In the second mixing process, the mass ratio of methyl vinyl silicone rubber, vulcanizing agent, foaming agent and foaming aid is 100:0.9-1.1:4-6:0.2-0.3; The second forming is a second thermoforming, the temperature of the second thermoforming is 100-130°C, the pressure is 5-10Pa, and the heat preservation and pressure holding time is 15-30min; The second vulcanization includes a third vulcanization and a fourth vulcanization performed sequentially, wherein the temperature of the third vulcanization is 100 to 130° C. and the time is 30 to 60 minutes; The temperature of the fourth stage vulcanization is 150-170° C. and the time is 2-4 hours.

10. Use of the sealing material according to any one of claims 1 to 6 or the sealing material prepared by the preparation method according to any one of claims 7 to 9 as a sealing strip.

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