Two-component polysulfide sealant and preparation method thereof

Abstract

According to the double-component polysulfide sealant and the preparation method thereof provided by the invention, the excellent hydrophobicity of organic silicon is utilized to perform end-capping modification on liquid polysulfide, so that the water absorption rate of the sealant is reduced, and the service life of the sealant in a long-term water immersion environment is prolonged; by utilizing the advantage that the two liquid polysulfides with different molecular weights have different activities, and regulating and controlling the specific proportion of the two liquid polysulfides, the elongation at break of the sealant after silane end-capping modification is improved, so that the sealant has excellent water resistance and flexibility; meanwhile, the sealant is convenient to use in a single packaging mode of a sealant injection barrel, good in extrusion performance and beneficial to construction and use, and is a double-component polysulfide sealant with excellent flexibility, water resistance, good processing performance and excellent comprehensive performance.

Description

Technical Field

[0001] The invention relates to the technical field of polysulfide sealants, and in particular to a two-component polysulfide sealant with excellent comprehensive performance and a preparation method thereof. Background Art

[0002] Polysulfide sealants have excellent solvent resistance due to the presence of a large number of saturated S atoms in their molecular chains. They also have excellent resistance to media, corrosion, and weathering. They are widely used in aviation, construction, automobiles, ships, hollow glass, petrochemicals, and other fields. As the application areas of polysulfide sealants continue to expand, more stringent requirements are placed on the performance of sealants. Therefore, in order to achieve high-quality and high-reliability sealing levels, it is necessary to improve the efficient bonding and sealing performance of polysulfide sealants in a variety of environments.

[0003] Although traditional two-component polysulfide sealants have a certain degree of water resistance, in an environment of long-term water immersion, water molecules will penetrate into the interface area between the polysulfide sealant and the bonded material, causing the sealant's bonding performance to decrease, thereby reducing the service life of the material. In addition, traditional two-component polysulfide sealants are mostly packaged in plastic barrels with base paste and vulcanizer in a certain proportion as a matching package. When preparing, the base paste and vulcanizer need to be weighed separately according to the ratio, which is inconvenient and difficult to control, and has poor process performance. Therefore, it is necessary to develop a two-component polysulfide sealant with excellent comprehensive performance that has excellent water resistance, flexibility and good process performance. Summary of the invention

[0004] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a two-component polysulfide sealant with excellent comprehensive performance, excellent water resistance, flexibility and good process performance, and a preparation method thereof. The present invention utilizes the excellent hydrophobicity of silicone to end-cap and modify the liquid polysulfide, thereby reducing the water absorption rate of the sealant and increasing the service life of the sealant in a long-term water immersion environment; and utilizing the advantages of the different activities of two liquid polysulfides with different molecular weights to adjust the ratio of the two liquid polysulfides, the elongation at break of the sealant after silane end-capping modification is increased, so that the sealant has both excellent water resistance and flexibility; and at the same time, provides a packaging method that is easy to operate, has good extrusion performance, and is conducive to construction use.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] Provided is a two-component polysulfide sealant with excellent comprehensive performance, comprising component A and component B; the raw material composition and weight proportion of component A are as follows:

[0007]

[0008] The raw material composition and weight proportion of the B component are as follows:

[0009]

[0010] The liquid polysulfide I in the A component is JLY-1225 with a number average molecular weight of 2500 g / mol, the liquid polysulfide II is JLY-124 with a number average molecular weight of 4000 g / mol, and the ratio of the liquid polysulfide I and II is 1:(0.3-3); the mass ratio of the A component to the B component is 100:(7-24);

[0011] The preparation method of the silane-terminated liquid polysulfide prepolymer in the A component comprises: weighing a certain amount of liquid polysulfide I and an epoxy coupling agent in a mass ratio of 5:1, adding them into a dry 500mL four-necked flask, equipped with a thermometer, a mechanical stirrer, a vacuum gauge, and an oil pump for vacuuming, and mechanically stirring for 30 minutes in a 60°C oil bath pot under vacuum to obtain the silane-terminated liquid polysulfide prepolymer.

[0012] The epoxy resin in the A component is any one or more combinations of bisphenol A epoxy resin 828, bisphenol A epoxy resin E-51, and bisphenol A epoxy resin E-44.

[0013] The reinforcing filler in the component A is any one or more combinations of nano-scale calcium carbonate, light calcium carbonate and heavy calcium carbonate.

[0014] The epoxy coupling agent is any one or more combinations of γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane and γ-glycidyloxypropylmethyldimethoxysilane.

[0015] The plasticizer in the B component is any one or more combinations of chlorinated paraffin, dibutyl phthalate, butyl benzyl phthalate and trioctyl trimellitate.

[0016] The silane coupling agent in the B component is any one or more combinations of γ-mercaptopropyltriethoxysilane and γ-mercaptopropyltrimethoxysilane.

[0017] The preparation method comprises the following steps:

[0018] (1) Preparation of silane-terminated liquid polysulfide prepolymer: Weigh a certain amount of liquid polysulfide I and epoxy coupling agent in a mass ratio of 5:1, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir for 30 minutes in a 60°C oil bath pot under vacuum to obtain a silane-terminated liquid polysulfide prepolymer;

[0019] (2) Preparation of component A: Weigh 15.63-51.72 parts of liquid polysulfide I, 15.63-51.72 parts of liquid polysulfide II, 6.25-6.89 parts of epoxy resin, 12.51-13.79 parts of reinforcing filler and 10.34-18.75 parts of silane-terminated polysulfide prepolymer, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and stir mechanically in an oil bath at 120° C. under vacuum for 1-2 hours to obtain component A;

[0020] (3) Preparation of component B: weigh 49.54-59.41 parts of manganese dioxide, 15.84-42.95 parts of diphenylguanidine, 4.02-12.87 parts of plasticizer, 3.09-10.01 parts of DMP-30 and 1.55-4.95 parts of silane coupling agent and mix them evenly to obtain component B;

[0021] (4) Preparation of a two-component polysulfide sealant: Add the component A described in step (2) and the component B described in step (3) into a glue injection cylinder at a ratio of 100:(7-24) to obtain a two-component polysulfide sealant.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The two-component polysulfide sealant prepared by the present invention has a tensile strength of 1.62 MPa, an elongation at break of 615%, a peel strength of 3.68 N / mm, and a water absorption rate of 0.43%; compared with the tensile strength of 1.34 MPa, an elongation at break of 288%, a peel strength of 3.41 N / mm, and a water absorption rate of 1.08% of the two-component polysulfide sealant without silane end-capping modification, the two-component polysulfide sealant has better mechanical properties and water resistance.

[0024] 2. The two-component polysulfide sealant prepared by the present invention improves the water resistance of the sealant by adding silane-terminated liquid polysulfide prepolymer. In the long-term water immersion environment, the infiltration of water molecules in the two-component polysulfide sealant without silane end-capping will reduce the adhesive performance of the sealant, thereby reducing the service life of the sealant. The present invention utilizes the excellent hydrophobicity of silicone to end-cap the liquid polysulfide silane through an epoxy silane coupling agent, thereby reducing the water absorption rate of the sealant and increasing the service life of the sealant in a long-term water immersion environment.

[0025] 3. The present invention takes advantage of the different reactivity of liquid polysulfides of different molecular weights, and improves the elongation at break after silane-terminated liquid polysulfide by regulating the ratio of the two liquid polysulfides. The two-component polysulfide sealant using a single liquid polysulfide has a shorter molecular chain and poorer flexibility after silane-terminated, which reduces its elongation at break. High molecular weight liquid polysulfide can improve its elongation at break due to its long molecular chain and good flexibility, but the addition of too much high molecular weight liquid polysulfide will cause the manganese dioxide curing system to be too fast, and the cured sealant will sacrifice some toughness due to its own high strength, thereby reducing its elongation at break; low molecular weight liquid polysulfide has a short molecular chain and low viscosity, which increases the activity of the molecular chain, improves the reaction activity of liquid polysulfide and epoxy resin, and thus improves the peel strength, but the addition of too much low molecular weight liquid polysulfide will cause the curing speed to be too slow, and the strength of the cured sealant will be reduced. The present invention improves the flexibility of the silane-terminated modified sealant by compounding two liquid polysulfides with different molecular weights, thereby achieving excellent water resistance and flexibility of the sealant, and achieving optimal performance of the sealant by adjusting the ratio of the two liquid polysulfides.

[0026] 4. The two-component polysulfide sealant injection cylinder single package prepared by the present invention is easy to use and has good extrusion performance. Traditional two-component polysulfide sealants are mostly packaged in a plastic barrel in which the base paste and the vulcanizer are separately packaged in a certain proportion as a matching package, which is inconvenient to operate and difficult to control, prone to uneven mixing, poor process performance, and affects the overall performance of the polysulfide sealant finally cured. The two-component polysulfide sealant injection cylinder single package prepared by us is a base paste cylinder and a push rod filled with a vulcanizer connected together. The base paste and the vulcanizer have a fixed ratio and can be used directly after mixing. It is easy to use, easy to control, and can extrude ≥15g / min within the specified applicable time, which is conducive to construction use. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. The following specific embodiments are provided by way of illustrating the present invention rather than limiting the present invention.

[0028] Embodiment 1:

[0029] (1) Preparation of silane-terminated liquid polysulfide prepolymer: Weigh a certain amount of liquid polysulfide I and epoxy coupling agent in a mass ratio of 5:1, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir for 30 minutes in a 60°C oil bath pot under vacuum to obtain a silane-terminated liquid polysulfide prepolymer;

[0030] (2) Preparation of component A: Weigh 51.72 parts of liquid polysulfide I, 17.24 parts of liquid polysulfide II, 6.89 parts of epoxy resin, 13.79 parts of reinforcing filler and 10.34 parts of silane-terminated polysulfide prepolymer, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and stir mechanically in an oil bath at 120° C. under vacuum for 1-2 h to obtain component A;

[0031] (3) Preparation of component B: 50.63 parts of manganese dioxide, 40.51 parts of diphenylguanidine, 4.11 parts of plasticizer, 3.16 parts of DMP-30 and 1.58 parts of silane coupling agent were weighed and mixed evenly to obtain component B;

[0032] (4) Preparation of two-component polysulfide sealant: Add component A described in step (2) and component B described in step (3) into a glue injection cylinder at a ratio of 100:(7-24) to obtain two-component polysulfide sealant 1.

[0033] Embodiment 2:

[0034] (1) Preparation of silane-terminated liquid polysulfide prepolymer: Weigh a certain amount of liquid polysulfide I and epoxy coupling agent in a mass ratio of 5:1, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir for 30 minutes in a 60°C oil bath pot under vacuum to obtain a silane-terminated liquid polysulfide prepolymer;

[0035] (2) Preparation of component A: Weigh 45.98 parts of liquid polysulfide I, 22.99 parts of liquid polysulfide II, 6.89 parts of epoxy resin, 13.79 parts of reinforcing filler and 10.34 parts of silane-terminated polysulfide prepolymer, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir in a 120° C. oil bath under vacuum for 1-2 h to obtain component A;

[0036] (3) Preparation of component B: 50.63 parts of manganese dioxide, 40.51 parts of diphenylguanidine, 4.11 parts of plasticizer, 3.16 parts of DMP-30 and 1.58 parts of silane coupling agent were weighed and mixed evenly to obtain component B;

[0037] (4) Preparation of two-component polysulfide sealant: Add component A described in step (2) and component B described in step (3) into a glue injection cylinder at a ratio of 100:(7-24) to obtain two-component polysulfide sealant 2.

[0038] Embodiment 3:

[0039] (1) Preparation of silane-terminated liquid polysulfide prepolymer: Weigh a certain amount of liquid polysulfide I and epoxy coupling agent in a mass ratio of 5:1, respectively, and equip with a thermometer, a mechanical stirrer, a vacuum gauge, and a vacuum pump, and mechanically stir for 30 minutes in a 60°C oil bath in a vacuum state to obtain a silane-terminated liquid polysulfide prepolymer;

[0040] (2) Preparation of component A: Weigh 34.48 parts of liquid polysulfide I, 34.48 parts of liquid polysulfide II, 6.89 parts of epoxy resin, 13.79 parts of reinforcing filler and 10.34 parts of silane-terminated polysulfide prepolymer, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir in an oil bath at 120° C. under vacuum for 1-2 h to obtain component A;

[0041] (3) Preparation of component B: 50.63 parts of manganese dioxide, 40.51 parts of diphenylguanidine, 4.11 parts of plasticizer, 3.16 parts of DMP-30 and 1.58 parts of silane coupling agent were weighed and mixed evenly to obtain component B;

[0042] (4) Preparation of two-component polysulfide sealant: Add component A described in step (2) and component B described in step (3) into a glue injection cylinder at a ratio of 100:(7-24) to obtain two-component polysulfide sealant 3.

[0043] Embodiment 4:

[0044] (1) Preparation of silane-terminated liquid polysulfide prepolymer: Weigh a certain amount of liquid polysulfide I and epoxy coupling agent in a mass ratio of 5:1, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir for 30 minutes in a 60°C oil bath pot under vacuum to obtain a silane-terminated liquid polysulfide prepolymer;

[0045] (2) Preparation of component A: Weigh 22.99 parts of liquid polysulfide I, 45.98 parts of liquid polysulfide II, 6.89 parts of epoxy resin, 13.79 parts of reinforcing filler and 10.34 parts of silane-terminated polysulfide prepolymer, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir in a 120° C. oil bath under vacuum for 1-2 h to obtain component A;

[0046] (3) Preparation of component B: 50.63 parts of manganese dioxide, 40.51 parts of diphenylguanidine, 4.11 parts of plasticizer, 3.16 parts of DMP-30 and 1.58 parts of silane coupling agent were weighed and mixed evenly to obtain component B;

[0047] (4) Preparation of two-component polysulfide sealant: Add component A described in step (2) and component B described in step (3) into a glue injection cylinder at a ratio of 100:(7-24) to obtain two-component polysulfide sealant 4.

[0048] Embodiment 5:

[0049] (1) Preparation of silane-terminated liquid polysulfide prepolymer: Weigh a certain amount of liquid polysulfide I and epoxy coupling agent in a mass ratio of 5:1, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir for 30 minutes in a 60°C oil bath pot under vacuum to obtain a silane-terminated liquid polysulfide prepolymer;

[0050] (2) Preparation of component A: Weigh 17.24 parts of liquid polysulfide I, 51.72 parts of liquid polysulfide II, 6.89 parts of epoxy resin, 13.79 parts of reinforcing filler and 10.34 parts of silane-terminated polysulfide prepolymer, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir in an oil bath at 120° C. under vacuum for 1-2 h to obtain component A;

[0051] (3) Preparation of component B: 50.63 parts of manganese dioxide, 40.51 parts of diphenylguanidine, 4.11 parts of plasticizer, 3.16 parts of DMP-30 and 1.58 parts of silane coupling agent were weighed and mixed evenly to obtain component B;

[0052] (4) Preparation of two-component polysulfide sealant: Add component A described in step (2) and component B described in step (3) into a glue injection cylinder at a ratio of 100:(7-24) to obtain two-component polysulfide sealant 5.

[0053] Comparative Example 1:

[0054] (1) Preparation of silane-terminated liquid polysulfide prepolymer: Weigh a certain amount of liquid polysulfide I and epoxy coupling agent in a mass ratio of 5:1, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir for 30 minutes in a 60°C oil bath pot under vacuum to obtain a silane-terminated liquid polysulfide prepolymer;

[0055] (2) Preparation of component A: Weigh 68.97 parts of liquid polysulfide I, 6.89 parts of epoxy resin, 13.79 parts of reinforcing filler and 10.34 parts of silane-terminated polysulfide prepolymer, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir in an oil bath at 120° C. under vacuum for 1-2 h to obtain component A;

[0056] (3) Preparation of component B: 50.63 parts of manganese dioxide, 40.51 parts of diphenylguanidine, 4.11 parts of plasticizer, 3.16 parts of DMP-30 and 1.58 parts of silane coupling agent were weighed and mixed evenly to obtain component B;

[0057] (4) Preparation of two-component polysulfide sealant: Add component A described in step (2) and component B described in step (3) into a glue injection cylinder at a ratio of 100:(7-24) to obtain a two-component polysulfide sealant (using a single low-weight liquid polysulfide I).

[0058] Comparative Example 2:

[0059] (1) Preparation of silane-terminated liquid polysulfide prepolymer: Weigh a certain amount of liquid polysulfide I and epoxy coupling agent in a mass ratio of 5:1, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir for 30 minutes in a 60°C oil bath pot under vacuum to obtain a silane-terminated liquid polysulfide prepolymer;

[0060] (2) Preparation of component A: Weigh 68.97 parts of liquid polysulfide II, 6.89 parts of epoxy resin, 13.79 parts of reinforcing filler and 10.34 parts of silane-terminated polysulfide prepolymer, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir in an oil bath at 120° C. under vacuum for 1-2 h to obtain component A;

[0061] (3) Preparation of component B: 50.63 parts of manganese dioxide, 40.51 parts of diphenylguanidine, 4.11 parts of plasticizer, 3.16 parts of DMP-30 and 1.58 parts of silane coupling agent were weighed and mixed evenly to obtain component B;

[0062] (4) Preparation of two-component polysulfide sealant: Add component A described in step (2) and component B described in step (3) into a glue injection cylinder at a ratio of 100:(7-24) to obtain a two-component polysulfide sealant (using a single high-weight liquid polysulfide II).

[0063] Comparative Example 3:

[0064] (1) Preparation of component A: Weigh 25.64 parts of liquid polysulfide I, 51.28 parts of liquid polysulfide II, 7.69 parts of epoxy resin, and 15.38 parts of reinforcing filler, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum pump, and mechanically stir in an oil bath at 120° C. under vacuum for 1-2 hours to obtain component A;

[0065] (2) Preparation of component B: 50.63 parts of manganese dioxide, 40.51 parts of diphenylguanidine, 4.11 parts of plasticizer, 3.16 parts of DMP-30 and 1.58 parts of silane coupling agent were weighed and mixed evenly to obtain component B;

[0066] (3) Preparation of a two-component polysulfide sealant: The component A described in step (1) and the component B described in step (2) are loaded into a glue injection cylinder at a ratio of 100:(7-24) to obtain a two-component polysulfide sealant (without using silane-terminated liquid polysulfide prepolymer).

[0067] Performance Testing

[0068] The tensile strength test and peel strength test of the corresponding products of Examples 1-5 and Comparative Examples 1-3 were tested on a SansiCMT6000 universal tensile testing machine according to GB / T528-2009 and GB / T 2792-2014, respectively. The water resistance of Example 4 and Comparative Example 3 was tested according to GB / T 1690-2010. After the corresponding products were placed in water at room temperature for 7 days, their absorption rates were compared.

[0069] The test results of tensile strength, elongation at break and peel strength of Examples 1-5 and Comparative Examples 1-3 are shown in Table 1.

[0070] Table 1: Performance test results of embodiments and comparative examples

[0071]

[0072] From the above test results, it can be seen that: 1. By comparing the test results of Comparative Examples 1 and 2 with Examples 1-5, it can be seen that after silane-terminated liquid polysulfide, the addition of different molecular weight compounded liquid polysulfide significantly improves its elongation at break compared with the sealant of single liquid polysulfide (Comparative Examples 1 and 2). 2. From the test results of Examples 1-5, it can be seen that with the continuous increase of high molecular weight liquid polysulfide II, its elongation at break continues to increase, but the addition of too much high molecular weight liquid polysulfide II (Example 5) loses some flexibility due to its excessive strength; with the continuous increase of low molecular weight liquid polysulfide I, its peel strength continues to increase, but the addition of too much low molecular weight liquid polysulfide I (Example 1) reduces the tensile strength and elongation at break. 3. From the above test results, it can be seen that when the ratio of liquid polysulfide I to liquid polysulfide II is 1:2 (Example 4), the tensile strength is 1.62MPa, the elongation at break is 615%, and the peel strength is 3.68N / mm, with the best comprehensive performance.

[0073] Table 2: Water absorption test results of Example 4 and Comparative Example 3

[0074] Sample name 7d water absorption (%) Example 4 0.43 Comparative Example 3 1.08

[0075] It can be seen from the above test results that the water absorption rate of the two-component polysulfide sealant prepared by the present invention is 0.43%, which is much lower than 1.08% of Comparative Example 3. This is mainly due to the excellent hydrophobicity of silicone. The present invention adds silane-terminated liquid polysulfide prepolymer, so the sealant exhibits good water resistance.

[0076] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

[0077] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0078] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A two-component polysulfide sealant, characterized in that: The polysulfide sealant comprises component A and component B; the raw material composition and weight proportion of component A are as follows: The raw material composition and weight proportion of the B component are as follows: The liquid polysulfide I in the A component is JLY-1225 with a number average molecular weight of 2500 g / mol, the liquid polysulfide II is JLY-124 with a number average molecular weight of 4000 g / mol, and the ratio of the liquid polysulfide I and II is 1:(0.3-3); the mass ratio of the A component to the B component is 100:(7-24); The preparation method of the silane-terminated liquid polysulfide prepolymer in the A component comprises: weighing a certain amount of liquid polysulfide I and an epoxy coupling agent in a mass ratio of 5:1, adding them into a dry 500mL four-necked flask, equipped with a thermometer, a mechanical stirrer, a vacuum gauge, and an oil pump for vacuuming, and mechanically stirring for 30 minutes in a 60°C oil bath pot under vacuum to obtain the silane-terminated liquid polysulfide prepolymer.

2. A two-component polysulfide sealant according to claim 1, characterized in that: The epoxy resin in the A component is any one or more combinations of bisphenol A epoxy resin 828, bisphenol A epoxy resin E-51, and bisphenol A epoxy resin E-44.

3. A two-component polysulfide sealant according to claim 1, characterized in that: The reinforcing filler in the component A is any one or more combinations of nano-scale calcium carbonate, light calcium carbonate and heavy calcium carbonate.

4. A two-component polysulfide sealant according to claim 1, characterized in that: The epoxy coupling agent is any one or more combinations of γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane and γ-glycidyloxypropylmethyldimethoxysilane.

5. A two-component polysulfide sealant according to claim 1, characterized in that: The plasticizer in the B component is any one or more combinations of chlorinated paraffin, dibutyl phthalate, butyl benzyl phthalate and trioctyl trimellitate.

6. A two-component polysulfide sealant according to claim 1, characterized in that: The silane coupling agent in the B component is any one or more combinations of γ-glycidyloxypropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane and γ-mercaptopropyltrimethoxysilane.

7. A two-component polysulfide sealant according to claim 1, wherein the preparation method comprises the following steps: (1) Preparation of silane-terminated liquid polysulfide prepolymer: Weigh a certain amount of liquid polysulfide I and epoxy coupling agent in a mass ratio of 5:1, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and mechanically stir for 30 minutes in a 60°C oil bath pot under vacuum to obtain a silane-terminated liquid polysulfide prepolymer; (2) Preparation of component A: Weigh 15.63-51.72 parts of liquid polysulfide I, 15.63-51.72 parts of liquid polysulfide II, 6.25-6.89 parts of epoxy resin, 12.51-13.79 parts of reinforcing filler and 10.34-18.75 parts of silane-terminated polysulfide prepolymer, add them into a dry 500 mL four-necked flask, equip it with a thermometer, mechanical stirring, vacuum gauge, and vacuum oil pump, and stir mechanically in an oil bath at 120° C. under vacuum for 1-2 hours to obtain component A; (3) Preparation of component B: weigh 49.54-59.41 parts of manganese dioxide, 15.84-42.95 parts of diphenylguanidine, 4.02-12.87 parts of plasticizer, 3.09-10.01 parts of DMP-30 and 1.55-4.95 parts of silane coupling agent and mix them evenly to obtain component B; (4) Preparation of a two-component polysulfide sealant: Add the component A described in step (2) and the component B described in step (3) into a glue injection cylinder at a ratio of 100:(7-24) to obtain a two-component polysulfide sealant.

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