A joint sealant for high-altitude airport runways and its preparation method

Abstract

The present invention relates to the technical field of runway joint sealants, and discloses a joint sealant for high-plateau airport runways and a preparation method thereof. The joint sealant comprises a base paste and a vulcanizing paste. The base paste includes liquid polysulfide raw rubber, ethyl vinyl sulfide, and auxiliary material A; the vulcanizing paste includes manganese dioxide, a photoinitiator, and auxiliary material B. The airport runway joint sealant provided by the present invention can effectively solve problems such as low curing rate of polysulfide joint sealants caused by large day-night temperature differences in high-plateau airports, poor performance after curing, and easy attenuation of performance caused by high-plateau ultraviolet radiation. Moreover, the curing rate can meet the requirements of non-stop operation construction, and has broad market application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of runway joint sealants, and in particular, to a joint sealant for high-altitude airports and a preparation method thereof. Background Art

[0002] Civil airport runways belong to civil aviation professional engineering and are special runways for aircraft takeoff and landing. For the cement concrete pavements in the flight area, the upper parts of the shrinkage joints and the closed expansion joints need to be filled with joint sealants to prevent the infiltration of aviation fuel, moisture, sundries, etc. on the runway. Otherwise, the hard sundries falling into the joints will cause the corner breakage of the cement concrete slab, the infiltrated moisture will reduce the stability of the base layer, and the leaked aviation kerosene from the aircraft will penetrate and cause environmental pollution. The runway joint sealant plays an important role, and the special climate conditions of high-altitude airports impose more stringent requirements on the performance of the runway joint sealant. If the selection and construction process of the joint sealant are rigorous during the construction process of the joint sealant, the strength of the pavement can be maintained, the service life of the pavement can be extended, and thus the safe operation of the airport runway can be ensured.

[0003] Currently, the commonly used joint sealant materials for airport runways are polysulfide and polyurethane. Among them, polysulfide is also used for the sealing of aircraft fuel tanks and has excellent resistance to aviation kerosene, which can effectively prevent the penetration and pollution of the leaked aviation kerosene on the airport runway and taxiway.

[0004] The polysulfide joint sealant is usually two-component for easy construction and needs to be mixed and cured at room temperature. The curing time is greatly affected by temperature. Within a certain range, the higher the temperature, the faster the curing rate, and the better the joint bonding effect and durability. When the temperature is lower than 5°C, the curing is insufficient, which easily causes a significant decline in the bonding and mechanical properties, and it is not suitable for caulking work.

[0005] High-altitude airports (airport elevation above 2,438 meters) have special environments such as high altitude, low air pressure, low oxygen content, low humidity, strong ultraviolet radiation, long sunshine time, and large temperature difference between day and night, which are much more complex than general airports.

[0006] On the one hand, if the polysulfide joint sealant for general airport runways is applied to high-altitude airports, the construction time and construction quality are difficult to control. In the actual construction experience of high-altitude airport runway joint sealants, the curing and maintenance of polysulfide glue are greatly affected by the weather. The temperature difference between day and night in high-altitude areas is large, and the maintenance time and the bonding effect after curing are unstable. Even, it is easy to have insufficient curing, resulting in poor joint filling effect, short service life, high replacement frequency, etc., increasing the maintenance cost, which will have a greater impact on the construction process and engineering quality guarantee.

[0007] On the other hand, due to the existence of disulfide bonds in the molecular structure of ordinary polysulfide glue (R-SS-R'), it is easily aged and decomposed in the strong ultraviolet radiation environment of high-altitude airports, resulting in the attenuation of adhesion and debonding, and the decline of mechanical properties.

[0008] Considering the above factors, the special climatic conditions of high-altitude airports are not suitable for using the polysulfide sealant for general airport runways, and it is necessary to modify and optimize the polysulfide sealant according to the characteristics of the service environment. Summary of the Invention

[0009] Technical problems to be solved by the present invention:

[0010] To solve the problem that the polysulfide sealant used for general airport runways is prone to aging and decomposition under strong ultraviolet radiation environment when applied to high-altitude airport runways, resulting in a decline in mechanical properties.

[0011] Technical solutions adopted by the present invention:

[0012] In view of the above technical problems, the object of the present invention is to provide a sealant for high-altitude airport runways and its preparation method. The specific content is as follows:

[0013] A sealant for high-altitude airport runways includes a base paste and a curing paste. The base paste includes liquid polysulfide raw rubber, ethyl vinyl sulfide, and auxiliary material A; the curing paste includes manganese dioxide, a photoinitiator, and auxiliary material B.

[0014] According to some optional embodiments, auxiliary material A includes active nano calcium carbonate, light calcium carbonate, fumed silica, magnesium stearate, dioctyl terephthalate, and vinyltriethoxysilane.

[0015] According to some optional embodiments, the components of the base paste are calculated by weight, including 98-100 parts of liquid polysulfide raw rubber, 8-9 parts of ethyl vinyl sulfide, 28-30 parts of active nano calcium carbonate, 4-5 parts of light calcium carbonate, 1-2 parts of fumed silica, 0.5-1 part of magnesium stearate, 8-9 parts of dioctyl terephthalate, and 0.1-0.5 part of vinyltriethoxysilane.

[0016] According to some optional embodiments, the components of the base paste are calculated by weight, including 100 parts of liquid polysulfide raw rubber, 8 parts of ethyl vinyl sulfide, 30 parts of active nano calcium carbonate, 5 parts of light calcium carbonate, 1 part of fumed silica, 1 part of magnesium stearate, 8.5 parts of dioctyl terephthalate, and 0.45 part of vinyltriethoxysilane.

[0017] According to some optional embodiments, the photoinitiator is Irgacure 2959.

[0018] According to some optional embodiments, auxiliary material B includes dioctyl terephthalate, 1,3-diphenylguanidine, carbon black, epoxy resin, and sulfur.

[0019] According to some optional embodiments, the components of the vulcanizing paste include, by weight, 90 parts of manganese dioxide, 0.1-0.2 parts of photoinitiator, 8-10 parts of dioctyl terephthalate, 5-7 parts of 1,3-biphenylguanidine, 8-10 parts of carbon black, 8-10 parts of epoxy resin, and 0.1-0.3 parts of sulfur.

[0020] According to some optional embodiments, the components of the vulcanizing paste are, by weight, 90 parts of manganese dioxide, 0.2 parts of photoinitiator, 9 parts of dioctyl terephthalate, 7 parts of 1,3-biphenylguanidine, 9 parts of carbon black, 9 parts of epoxy resin, and 0.25 parts of sulfur.

[0021] According to some optional embodiments, the liquid polysulfide rubber is obtained by mixing liquid polysulfide rubbers with weight average molecular weights of 2000 and 4500 in a mass ratio of 3-5:5-7. A further preferred ratio is 4:6.

[0022] According to some optional embodiments, the mass ratio of the base paste to the vulcanizing paste is 100:8-10, more preferably 100:8.5-9, and even more preferably 100:9.

[0023] Second, the present invention provides a method for preparing the aforementioned high plateau airport runway filler, comprising the following steps:

[0024] Weigh each component of the base paste, and blend them (a planetary mixer may be selected as the blending equipment) to obtain the base paste;

[0025] Weigh each component of the vulcanized paste, grind it (a three-roll grinder can be selected as the grinding equipment) to obtain the vulcanized paste;

[0026] The base paste and the vulcanized paste are mixed to obtain a joint filler for high-altitude airport runways.

[0027] The technical mechanism adopted by the present invention and the beneficial effects achieved are:

[0028] The high plateau airport runway caulking material provided by the present invention utilizes polysulfide raw rubber to generate a cured product containing a disulfide bond (R-SS-R') under the action of a manganese dioxide oxidant, and at the same time, polysulfide raw rubber and ethyl vinyl sulfide are photopolymerized and cured under a high plateau strong ultraviolet environment and a photoinitiator to generate a cured product containing a thioether bond (-CS-), as a supplement to the oxidative curing of the polysulfide caulking material; after the thioether bond (-CS-) is introduced into the cured product, the bonding performance and mechanical properties are more excellent, and the bonding performance and mechanical properties are not easy to decay under a strong ultraviolet service environment. The airport runway caulking material provided by the present invention can effectively solve the problems of low curing rate of polysulfide caulking material caused by large temperature difference between day and night at high plateau airports, poor performance after curing, and easy attenuation of performance due to ultraviolet radiation from high plateaus, and the curing rate can meet the requirements of non-stop construction, and has broad market application prospects. Brief Description of the Drawings

[0029] Figure 1 Physical diagram of the adhesion test result of the caulking material prepared in Example 1;

[0030] Figure 2 Physical diagram of the adhesion test result of the caulking material prepared in Comparative Example 3. Detailed Description of the Invention

[0031] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are followed. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0032] <Example>

[0033] Example 1

[0034] This embodiment provides a preparation method for a caulking material for high-altitude airport runways, including the following steps:

[0035] Take 100 g of liquid polysulfide raw rubber (a mixture of liquid polysulfide raw rubber with a weight average molecular weight of 2000 and 4500 in a mass ratio of 4:6), 8 g of ethyl vinyl sulfide, 30 g of active nano calcium carbonate, 5 g of light calcium carbonate, 1 g of fumed silica, 1 g of magnesium stearate, 8.5 g of dioctyl terephthalate, and 0.45 g of vinyltriethoxysilane, grind them on a three-roll mill for 10 minutes to obtain a base paste; take 90 g of manganese dioxide, 0.2 g of Irgacure 2959, 9 g of dioctyl terephthalate, 7 g of 1,3-biphenylguanidine, 9 g of carbon black, 9 g of epoxy resin, and 0.25 g of sulfur, grind them on a three-roll mill for 10 minutes to obtain a vulcanizing paste, obtaining a two-component product. When in use, mix the two components evenly to obtain caulking material 1.

[0036] <Comparative Example>

[0037] Comparative Example 1

[0038] This comparative example provides a preparation method for a caulking material for high-altitude airport runways, including the following steps:

[0039] Take 100 g of liquid polysulfide raw rubber (a mixture of liquid polysulfide raw rubbers with weight average molecular weights of 2000 and 4500 in a mass ratio of 4:6), 6 g of ethyl vinyl sulfide, 30 g of active nano calcium carbonate, 5 g of light calcium carbonate, 1 g of fumed silica, 1 g of magnesium stearate, 8.5 g of dioctyl terephthalate, and 0.45 g of vinyltriethoxysilane, grind them on a three-roll mill for 10 minutes to obtain a base paste; take 90 g of manganese dioxide, 0.15 g of Irgacure 2959, 9 g of dioctyl terephthalate, 7 g of 1,3-biphenylguanidine, 9 g of carbon black, 9 g of epoxy resin, and 0.25 g of sulfur, grind them on a three-roll mill for 10 minutes to obtain a curing paste, to obtain a two-component product. When in use, mix the two components evenly to obtain sealant 2.

[0040] Comparative Example 2

[0041] This comparative example provides a preparation method of a sealant for high-altitude airport runways, including the following steps:

[0042] Take 100 g of liquid polysulfide raw rubber (a mixture of liquid polysulfide raw rubbers with weight average molecular weights of 2000 and 4500 in a mass ratio of 4:6), 10 g of ethyl vinyl sulfide, 30 g of active nano calcium carbonate, 5 g of light calcium carbonate, 1 g of fumed silica, 1 g of magnesium stearate, 8.5 g of dioctyl terephthalate, and 0.45 g of vinyltriethoxysilane, grind them on a three-roll mill for 10 minutes to obtain a base paste; take 90 g of manganese dioxide, 0.25 g of Irgacure 2959, 9 g of dioctyl terephthalate, 7 g of 1,3-biphenylguanidine, 9 g of carbon black, 9 g of epoxy resin, and 0.25 g of sulfur, grind them on a three-roll mill for 5 minutes to obtain a curing paste, to obtain a two-component sealant. When in use, mix the two components evenly to obtain sealant 3.

[0043] Comparative Example 3

[0044] This comparative example provides a preparation method of a sealant for high-altitude airport runways, including the following steps:

[0045] Take 100 g of liquid polysulfide raw rubber (a mixture of liquid polysulfide raw rubbers with weight average molecular weights of 2000 and 4500 in a mass ratio of 4:6), 30 g of active nano calcium carbonate, 5 g of light calcium carbonate, 1 g of fumed silica, 1 g of magnesium stearate, 8.5 g of dioctyl terephthalate, and 0.45 g of vinyltriethoxysilane, grind them on a three-roll mill for 10 minutes to obtain a base paste; take 100 g of manganese dioxide, 10 g of dioctyl terephthalate, 8 g of 1,3-biphenylguanidine, 10 g of carbon black, 10 g of epoxy resin, and 0.3 g of sulfur, grind them on a three-roll mill for 5 minutes to obtain a curing paste, to obtain a two-component sealant. When in use, mix the two components evenly to obtain sealant 4.

[0046] <Test Example>

[0047] Curing performance test

[0048] According to the requirements of the Civil Aviation Standard MH 5006 "Technical Specification for the Construction of Cement Concrete Pavement of Civil Airports", in accordance with the standards GB / T 13477.17 "Test Methods for Building Sealants - Part 17: Determination of Elastic Recovery Rate", GB / T 13477.13 "Test Methods for Building Sealants - Part 13: Determination of Adhesion after Cold Drawing - Hot Pressing" (in cold regions: elongation rate +40% at -30±2°C; compression rate -12.5% at 40±2°C), GB / T 13477.5 "Test Methods for Building Sealants - Part 5: Determination of Skin Drying Time", ASTM D2240 "Standard Test Methods for Rubber Properties - Durometer Hardness", the standard concrete specimens made of Example 1 and Comparative Examples 1 - 3 were respectively tested under a low - temperature ultraviolet radiation environment (taking the average daily ultraviolet light intensity of high - altitude airports as 55 W·m -2 , using a UVA340 ultraviolet lamp with a radiation intensity of 0.034 W·m -2 to irradiate, adjusting the ultraviolet intensity on the surface of the test specimens to 55 W·m -2 , placing them in a low - temperature chamber at 3°C to simulate the construction environment of high - altitude airports with high cold and strong ultraviolet. The skin drying time, hardness after 7 days of curing, and hardness, elastic recovery rate, tensile modulus, and elongation at break after 28 days of curing were tested. The test results are shown in Table 1.

[0049] Table 1 Test Results of the Curing Performance of the Sealant

[0050]

[0051] Anti-ultraviolet aging performance test

[0052] Taking 350 MJ·m -2 to represent the total annual ultraviolet radiation intensity of high - altitude airports, artificial accelerated ultraviolet aging was carried out using a UVA340 ultraviolet lamp with a radiation intensity of 0.034 Mw·m -2 at a distance of 50 mm from the specimen, and the lamp spacing was 70 mm. According to the principle of equivalence of indoor and outdoor ultraviolet radiation intensity, through calculation, the outdoor ultraviolet radiation time of two years was converted into the radiation time of the indoor ultraviolet aging chamber as 576 hours (24 days).

[0053] According to the requirements of the civil aviation standard MH 5006 Technical Specification for the Construction of Cement Concrete Pavement of Civil Airports, in accordance with the standards GB / T 13477.17, GB / T 13477.13, ASTM D2377, and ASTM D2240, the hardness, elastic recovery rate, tensile modulus, elongation at break, adhesion of concrete specimens, etc. of the joint sealant of the present invention and the concrete standard specimens of the comparative examples were respectively tested before and after accelerating aging for 576 hours in the above-mentioned ultraviolet aging chamber (placed in a low-temperature chamber at 3°C). The test results are shown in Table 1. The physical diagram of the adhesion measurement is shown in Figure 1 (Example 1) and Figure 2 (Comparative Example 3).

[0054] Table 2 Anti-ultraviolet aging performance of joint sealant

[0055]

[0056] From the perspective of the formula, compared with Comparative Example 3, Example 1, Comparative Example 1, and Comparative Example 2 introduced ethyl vinyl sulfide and photoinitiator Irgacure 2959. Under the action of the photoinitiator and ultraviolet radiation, ethyl vinyl sulfide and polysulfide raw rubber underwent a photopolymerization reaction to generate a cured product containing a sulfide bond (-C-S-). This not only improved the curing degree of Example 1, Comparative Example 1, and Comparative Example 1 in the low-temperature ultraviolet environment, but also the bond energy of the product was higher than that of the disulfide bond (R-S-S-R’) in Comparative Example 2, resulting in better mechanical properties and resistance to high-cold and strong ultraviolet radiation aging performance. However, due to different formula ratios, the content of the cured product containing a sulfide bond (-C-S-) in the product was different. Therefore, there were significant differences in the mechanical properties and resistance to high-cold and strong ultraviolet radiation aging performance among Example 1, Comparative Example 1, and Comparative Example 2: Example 1 had the best mechanical properties and resistance to high-cold and strong ultraviolet radiation aging performance, indicating that the content of sulfide bonds (-C-S-) in the cured product was the highest, and its formula was the optimal one under the construction conditions of high-cold and strong ultraviolet radiation; the comprehensive performance of Comparative Example 2 was better than that of Comparative Example 1, indicating that the content of sulfide bonds (-C-S-) in the cured product was higher than that of Comparative Example 1, but still did not meet the standard requirements. Therefore, the formulas of Comparative Example 1 and Comparative Example 2 were not applicable to the airport construction conditions of high-cold and strong ultraviolet radiation.

[0057] From the perspective of curing performance, the surface drying time of Example 1, Comparative Example 1, and Comparative Example 2 in the low-temperature ultraviolet radiation environment was less than 16 hours, meeting the requirements of the civil aviation MH 5006 standard, while Comparative Example 3 did not meet the construction standard requirements, indicating that the introduction of ethyl vinyl sulfide and photoinitiator improved the curing speed of the joint sealant in the high-cold and strong ultraviolet environment.

[0058] In terms of curing performance, the surface drying time of Example 1 is only 6 hours, which is of great significance for non-stop construction under the alpine conditions of high-altitude airports (MH 5006 requires that the surface drying time should not exceed 6 hours during non-stop construction). Among the mechanical properties after 28 days of curing, the Civil Aviation MH 5006 standard requires that the elastic recovery rate ≥ 80 / %, the tensile modulus at 23°C ≤ 0.4 MPa, and the tensile modulus at -20°C ≤ 0.6 MPa. Only Example 1 fully meets the standard requirements, indicating that the sealant provided by the present invention can still reach a high degree of curing in a short curing time under the strong ultraviolet environment with large day-night temperature differences, and the bonding performance and mechanical properties after curing meet the requirements of civil aviation construction.

[0059] In terms of curing performance, the tensile modulus of Comparative Example 2 meets the requirement, but the elastic recovery rate is slightly lower than the requirement.

[0060] In terms of curing performance, the tensile modulus and elastic recovery rate of Comparative Example 1 and Comparative Example 3 do not meet the requirements.

[0061] In terms of the performance of resisting alpine and strong ultraviolet radiation, after two years in the actual service environment of artificially simulating the alpine and strong ultraviolet radiation of high-altitude airports, the mechanical properties and bonding performance of Comparative Example 3 are the worst. The bonding failure form after ultraviolet aging is no longer cohesive failure, but interfacial failure at the bonding interface between the joint sealant and concrete, indicating that the internal molecular chain scission fails and the adhesiveness to concrete is lost. Only Example 1 still meets the requirements of the Civil Aviation MH 5006 standard after ultraviolet aging (elastic recovery rate ≥ 80 / %, tensile modulus at 23°C ≤ 0.4 MPa, tensile modulus at -20°C ≤ 0.6 MPa); the performance of Comparative Example 2 barely meets the standard requirements before ultraviolet aging, but after artificial accelerated aging, the mechanical properties and bonding performance decrease significantly.

[0062] The performance of Example 1 is higher than that of Comparative Example 1 and Comparative Example 2 in all aspects, indicating that 0.2 g of Irgacure 2959 photoinitiator in Example 1 is the optimal ratio for initiating the photopolymerization reaction of 8 g of ethyl vinyl sulfide and liquid polysulfide rubber. At the same time, the redox reaction between liquid polysulfide rubber and manganese dioxide is also taking place in Example 1. Liquid polysulfide rubber is the consumed monomer in both reactions. Only the formulation of Example 1 can make the two components cure into a sealant with performance meeting the civil aviation construction standard under the alpine and strong ultraviolet environment.

[0063] In summary, the surface drying time of Example 1, the hardness after 7 days of curing, the elastic recovery rate, tensile modulus, elongation at break after 28 days of curing, and the elastic recovery rate, tensile modulus, elongation at break, and hardness after two years of artificial ultraviolet aging are far superior to those of Comparative Example 3, indicating that the introduction of ethyl vinyl sulfide and photoinitiator Irgacure 2959 causes the polysulfide rubber to undergo a photopolymerization reaction under ultraviolet radiation, generating a cured product containing sulfur ether bonds (-C-S-) with more stable bond energy.

[0064] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high-altitude airport runway filler, comprising a base paste and a vulcanized paste, characterized in that: The base paste includes liquid polysulfide rubber, ethyl vinyl sulfide, and auxiliary material A; the vulcanizing paste includes manganese dioxide, a photoinitiator, and auxiliary material B; Excipient A includes active nano calcium carbonate, light calcium carbonate, fumed silica, magnesium stearate, dioctyl terephthalate, and vinyl triethoxysilane; Auxiliary material B includes dioctyl terephthalate, 1,3-biphenylguanidine, carbon black, epoxy resin, and sulfur; The photoinitiator was Irgacure 2959; The components of the base paste are calculated by weight and include 98-100 parts of liquid polysulfide rubber, 8 parts of ethyl vinyl sulfide, 28-30 parts of active nano calcium carbonate, 4-5 parts of light calcium carbonate, 1-2 parts of fumed silica, 0.5-1 parts of magnesium stearate, 8-9 parts of dioctyl terephthalate, and 0.1-0.5 parts of vinyl triethoxy silane.

2. The high plateau airport runway filler according to claim 1, characterized in that: The components of the base paste are calculated by weight and include 100 parts of liquid polysulfide rubber, 8 parts of ethyl vinyl sulfide, 30 parts of active nano calcium carbonate, 5 parts of light calcium carbonate, 1 part of fumed silica, 1 part of magnesium stearate, 8.5 parts of dioctyl terephthalate, and 0.45 parts of vinyl triethoxysilane.

3. The high plateau airport runway filler according to claim 1, characterized in that: The components of the vulcanizing paste are calculated by weight and include 90 parts of manganese dioxide, 0.1-0.2 parts of photoinitiator, 8-10 parts of dioctyl terephthalate, 5-7 parts of 1,3-biphenylguanidine, 8-10 parts of carbon black, 8-10 parts of epoxy resin, and 0.1-0.3 parts of sulfur.

4. The high plateau airport runway filler according to claim 3, characterized in that: The components of the vulcanizing paste are calculated by weight: 90 parts of manganese dioxide, 0.2 parts of photoinitiator, 9 parts of dioctyl terephthalate, 7 parts of 1,3-biphenylguanidine, 9 parts of carbon black, 9 parts of epoxy resin, and 0.25 parts of sulfur.

5. The high plateau airport runway filler according to claim 1, characterized in that: The liquid polysulfide rubber is obtained by mixing liquid polysulfide rubbers with weight average molecular weights of 2000 and 4500 in a mass ratio of 3-5:5-7.

6. The high plateau airport runway filler according to claim 1, characterized in that: The mass ratio of base paste to vulcanizing paste is 100:8~10.

7. A method for preparing a high-altitude airport runway filler as claimed in any one of claims 1 to 6, characterized in that: The steps include: Weigh each component of the base paste and blend them to obtain the base paste; Weigh each component of the vulcanizing paste, grind it, and obtain the vulcanizing paste; The base paste and the vulcanized paste are mixed to obtain a joint filler for high-altitude airport runways.

Images