Silane-modified sealant for ballastless track caulking and preparation method thereof

Abstract

The present application relates to the field of sealants, and in particular to a silane-modified sealant for ballastless track caulking and a preparation method thereof. A silane-modified sealant for ballastless track caulking is prepared from the following raw materials: a silane-modified polymer, a plasticizer, a filler, a thixotropic agent, an anti-ultraviolet agent, a light stabilizer, a heat stabilizer, a water scavenger, a silane coupling agent, a curing agent and a curing accelerator. The thixotropic agent includes a functional polyamide, 3,6-dioxa-1,8-dithiol and azobisisobutyronitrile. The preparation method is as follows: mixing the curing agent and the curing accelerator and activating the reaction; mixing the silane-modified polymer, the plasticizer, the filler, the thixotropic agent, the anti-ultraviolet agent, the light stabilizer and the heat stabilizer and stirring them at high speed, and performing a vacuum treatment, heating the temperature, lowering the temperature, adding a water scavenger, adding a silane coupling agent, and activating the curing agent and curing accelerator to obtain a product. The present application has the advantage of improving the elastic recovery rate of the silane-modified sealant.

Description

Technical Field

[0001] The present application relates to the field of sealants, and in particular to a silane-modified sealant for caulking ballastless tracks and a preparation method thereof. Background Art

[0002] In ballastless track structures, in order to ensure the smoothness and stability of the overall structure, expansion joints are often required to be set at regular intervals to adapt to the deformation of the concrete structure at different temperatures. Therefore, elastic caulking materials are required for waterproof sealing. Elastic caulking materials generally use polyurethane sealants or silicone sealants.

[0003] Long-term use of polyurethane sealants in railway caulking exposes several issues. For example, polyurethane sealants are prone to bubble formation. While this can be minimized during the production process, it reduces efficiency and requires specialized personnel, increasing the difficulty of production. The slightest carelessness leading to bubble formation can reduce the sealant's performance. Furthermore, this type of sealant has poor weather resistance. While silicone sealants offer excellent weather resistance, they suffer from poor water resistance during application and poor coating performance. If the sealing of the caulking material fails, water will enter the ballastless track structure along the joints, affecting the smoothness of the line during the operation of high-speed trains and causing driving safety hazards. Silane-modified sealants have good weather resistance and strong adhesion, but to ensure that they can adapt to the deformation of concrete at different temperatures, the sealant needs to have a high elastic recovery rate. The elastic recovery rate of silane-modified sealants is poor and cannot meet the high requirements of the Chinese Railway Standard "Q-CR 601-2017 Railway Ballastless Track Caulking Materials". As a result, silane-modified sealants are difficult to use in ballastless track caulking materials. Summary of the Invention

[0004] In order to improve the elastic recovery rate of the silane-modified sealant, the present application provides a silane-modified sealant for ballastless track caulking and a preparation method thereof.

[0005] In the first aspect, the present application provides a silane-modified sealant for caulking of ballastless track, which adopts the following technical solution: a silane-modified sealant for caulking of ballastless track, comprising the following raw materials in parts by weight: 80-120 parts of silane-modified polymer, 60-100 parts of plasticizer, 150-210 parts of filler, 2-10 parts of thixotropic agent, 0.5-3 parts of anti-ultraviolet agent, 0.5-3 parts of light stabilizer, 0.5-3 parts of heat stabilizer, 3-6 parts of dehydrating agent, 3-6 parts of A silane coupling agent, 3-7 parts of a curing agent and 1-3 parts of a curing accelerator, the silane-modified polymer includes one or more combinations of S327, S203, S801, SAX510, SX5830E, and S888E, the thixotropic agent includes functional polyamide, 3,6-dioxa-1,8-dithiol and azobisisobutyronitrile, and the mass ratio of the functional polyamide, 3,6-dioxa-1,8-dithiol and azobisisobutyronitrile is 1:0.3-0.5:0.01.

[0006] By adopting the above technical solution and using azobisisobutyronitrile as an initiator, 3,6-dioxa-1,8-dithiol is grafted onto the functional polyamide, so that the thixotropic agent can improve the mechanical strength, elasticity and elastic recovery rate of the system.

[0007] Preferably, the functional polyamide comprises 1,3-diamino-2-propanol, 10-undecenoic acid methyl ester, butyric anhydride and 4-dimethylaminopyridine, and the mass ratio of the 1,3-diamino-2-propanol, 10-undecenoic acid methyl ester, butyric anhydride, 4-dimethylaminopyridine and is 1:4-5:1-2:0.03.

[0008] Preferably, the preparation of the thixotropic agent comprises the following steps:

[0009] Step 1: Add accurately measured 1,3-diamino-2-propanol and 10-undecenoic acid methyl ester to anhydrous tetrahydrofuran, heat to 60-70°C, continue stirring, and react for 22-26 hours; then add accurately measured butyric anhydride and 4-dimethylaminopyridine, change the temperature to 55-65°C, continue stirring, and continue reacting for 22-26 hours. After the reaction is completed, add deionized water, dry over anhydrous magnesium sulfate, and then dry at 100-110°C for 1-2 hours to obtain a functional polyamide;

[0010] Step 2: Add accurately measured functional polyamide, 3,6-dioxa-1,8-dithiol and azobisisobutyronitrile to anhydrous tetrahydrofuran and mix evenly. Heat the temperature to 60-70°C, continue stirring, and react for 22-26 hours. After the reaction is completed, add methanol, take the precipitate, and then dry it at 40-50°C for 3-5 hours to obtain a thixotropic agent.

[0011] By adopting the above technical solution, 1,3-diamino-2-propanol is grafted onto the main chain of 10-undecenoic acid methyl ester, so that the main chain has hydroxyl groups. The hydroxyl groups can be used to modify the reaction functional groups into other side groups as side chains. At this time, butyric anhydride is grafted onto the hydroxyl groups of the main chain using 4-dimethylaminopyridine as an initiator. Finally, 3,6-dioxa-1,8-dithiol is grafted onto the side chain using azobisisobutyronitrile as an initiator to form an elastic amorphous structure. The linear alkyl chain stacking and side groups are utilized to improve the mechanical strength of the system. The functional polyamide can guide tensile deformation, induce structural orientation, and improve the elastic recovery rate.

[0012] Preferably, the filler includes one or more combinations of modified composite calcium carbonate, clay, talc, carbon black and organic bentonite.

[0013] By adopting the above technical solution, calcium carbonate, clay, talc, carbon black and organic bentonite are all very effective reinforcing fillers, which can effectively improve the mechanical strength of the colloid system and play a role in regulating the viscosity of the system.

[0014] Preferably, the modified composite calcium carbonate comprises nano calcium carbonate, light calcium carbonate and stearic acid, the mass ratio of the nano calcium carbonate, light calcium carbonate and stearic acid is 2-4:1-3:0.25, and the mass ratio of the modified composite calcium carbonate and carbon black is 1:2-4.

[0015] By adopting the above technical solution, the smaller the particle size of the filler, the more conducive it is to improving the performance of the sealant. If nano calcium carbonate is used alone, the tensile strength of the sealant can be effectively improved, but the cost of using nano calcium carbonate alone is too high. Although the tensile strength is affected to a certain extent when compounded with light calcium carbonate, it can increase the elongation at break of the sealant and reduce its tensile modulus. The compounding of light calcium carbonate and nano calcium carbonate can also effectively reduce the production cost of the sealant while ensuring the required performance of the sealant and improving some of its performance.

[0016] Preferably, the plasticizer includes one or more combinations of diisononyl phthalate, diisooctyl phthalate, diisodecyl phthalate, PPG1000, PPG2000, PPG3000, PPG4000 and PPG8000; and the mass ratio of the filler to the plasticizer is 15-21:6-10.

[0017] By adopting the above technical solution, adding different amounts of plasticizers to the sealant will affect its performance, and different types of plasticizers will also affect the performance of the sealant. In order to ensure the performance of the sealant, this application selects a suitable type of plasticizer and controls the addition ratio of plasticizer to filler so that the elasticity and elastic recovery rate of the system are at the optimal value.

[0018] Preferably, the heat stabilizer includes one or more combinations of antioxidant 1076, antioxidant 245, antioxidant Irgafos168 and antioxidant Topanol; the light stabilizer is one or more combinations of light stabilizer 292, light stabilizer 770, light stabilizer 765, light stabilizer 622 and light stabilizer 5050H; and the anti-ultraviolet agent is a benzotriazole ultraviolet absorber.

[0019] By adopting the above technical solution, antioxidant 1076 and antioxidant 245 are BASF hindered phenol antioxidants, antioxidant Topanol is an asymmetric hindered phenol antioxidant, and antioxidant Irgafos168 is a phosphite antioxidant, which is colorless, color-discoloring, and has good compatibility. When used together with phenolic antioxidants, it has a synergistic effect and can react with peroxides produced by polymer auto-oxidation to degrade the polymer produced by processing and prolong the antioxidant performance of the main antioxidant; light stabilizer 292, light stabilizer 770, light stabilizer 765, light stabilizer 622 and light stabilizer 5050H are hindered amine light stabilizers, which have a good anti-ultraviolet effect when used in combination with benzotriazole ultraviolet absorbers, slow down the aging of the colloid, and prolong the service life.

[0020] Preferably, the silane coupling agent includes 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, phenylamino-silane, triaminosilane, γ-mercaptopropyltrimethoxysilane, γ-ureapropyltrimethoxysilane, γ-ureapropyltriethoxysilane and one or more combinations of γ-methacryloxypropyltrimethoxysilane.

[0021] By adopting the above technical solution, the silane coupling agent can modify the filler so that the filler and the polymer can be grafted through the coupling agent, thereby improving the dispersibility of the filler and the connection strength between the filler and the polymer.

[0022] In a second aspect, the present application provides a method for preparing a silane-modified sealant for caulking ballastless tracks, which adopts the following technical solution:

[0023] A method for preparing a silane-modified sealant for ballastless track caulking comprises the following steps:

[0024] Step 1: Mix the curing agent and curing accelerator in accurate amounts and stir evenly. After stirring evenly, activate the reaction for 1-1.5 hours and set aside.

[0025] Step 2: Mix the accurately measured silane-modified polymer, plasticizer, filler, thixotropic agent, anti-ultraviolet agent, light stabilizer, and heat stabilizer at a high speed and stir at a speed of 600-800 rpm, and perform vacuum treatment for 60-70 minutes, then heat the temperature to 100-120°C, and reduce the speed to 300-600 rpm for 110-130 minutes, then reduce the temperature to 40-50°C, add the accurately measured dehydrating agent, and then reduce the speed to 200-300 rpm for 15-25 minutes, then add the accurately measured silane coupling agent, maintain the speed at 200-300 rpm for 20-30 minutes, and finally add the curing agent and curing accelerator after the activation reaction in step 1, maintain the speed at 200-300 rpm for 20-30 minutes to obtain the product.

[0026] Preferably, before adding the filler, the filler is first pressurized and heated at a temperature of 400-450° C., a pressure of 0.1-0.2 MPa, and a time of 1-1.5 h.

[0027] By adopting the above technical solution, under the condition of 400-450°C, the original structure of calcium carbonate can be transformed into calcite structure, and the calcite structure is stable. The use of calcite-type calcium carbonate fillers in sealants will have good thixotropy and high tensile strength.

[0028] In summary, this application has the following beneficial effects:

[0029] 1. The specific thixotropic agent prepared in this application improves the elasticity, elastic recovery rate and mechanical strength of the sealant, and is combined with a filler compounded with modified nano-calcium carbonate, light calcium carbonate and carbon black to improve the various properties of the sealant, so that the prepared sealant can better adapt to the conditions required for caulking of ballastless track.

[0030] 2. The sealant of the present application is configured by adjusting the temperature, rotation speed and other parameters specified in the present application to improve the performance of the sealant. The curing agent and curing accelerator are activated before being added to improve the surface drying rate and mechanical strength of the sealant. The modified composite calcium carbonate is heated and pressurized to change the structure of the modified composite calcium carbonate, so that the sealant has better thixotropic properties and mechanical strength. DETAILED DESCRIPTION

[0031] Preparation Example

[0032] Preparation Example 1

[0033] The preparation of the thixotropic agent includes the following steps:

[0034] Step 1: 0.1 kg of 1,3-diamino-2-propanol, 0.4 kg of 10-undecenoic acid methyl ester and 500 ml of anhydrous tetrahydrofuran were added to a stirrer, heated to 65 ° C, continuously stirred at a speed of 200 rpm, and reacted for 24 hours; then 0.1 kg of butyric anhydride and 3 g of 4-dimethylaminopyridine were added, the temperature was lowered to 60 ° C, continuously stirred at a speed of 200 rpm, and the reaction was continued for 24 hours. After the reaction was completed, 150 ml of deionized water was added, and then dried over anhydrous magnesium sulfate. After drying, the magnesium sulfate that absorbed water was removed and then dried at 100 ° C for 1.5 hours to obtain a functional polyamide;

[0035] Step 2: Take 0.1 kg of the functional polyamide in step 1, 0.03 kg of 3,6-dioxa-1,8-dithiol, 1 g of azobisisobutyronitrile and 500 ml of anhydrous tetrahydrofuran, add them into a stirrer and mix evenly, heat the temperature to 65 ° C, continue stirring, rotate at 200 rpm, and react for 24 hours. After the reaction is completed, add 1500 ml of methanol to precipitate the grafted product, take the precipitate, and then dry it in a vacuum dryer at 45 ° C for 4 hours to obtain a thixotropic agent.

[0036] Preparation Example 2

[0037] The difference between Preparation Example 2 and Preparation Example 1 is that 0.5 kg of 10-undecenoic acid methyl ester was added instead of 0.4 kg of 10-undecenoic acid methyl ester added in step 1.

[0038] Preparation Example 3

[0039] The difference between Preparation Example 3 and Preparation Example 1 is that 0.45 kg of 10-undecenoic acid methyl ester was added instead of 0.4 kg of 10-undecenoic acid methyl ester in step 1.

[0040] Preparation Example 4

[0041] The difference between Preparation Example 4 and Preparation Example 1 is that: 0.45 kg of 10-undecenoic acid methyl ester was added instead of 0.4 kg; and 0.2 kg of butyric anhydride was added instead of 0.1 kg in step 1.

[0042] Preparation Example 5

[0043] The difference between Preparation Example 5 and Preparation Example 1 is that 0.45 kg of 10-undecenoic acid methyl ester was added instead of 0.4 kg of 10-undecenoic acid methyl ester in step 1; and 0.15 kg of butyric anhydride was added instead of 0.1 kg of butyric anhydride in step 1.

[0044] Preparation Example 6

[0045] The difference between Preparation Example 6 and Preparation Example 1 is that the 0.4 kg of 10-undecenoic acid methyl ester added in step 1 is replaced by 0.45 kg of 10-undecenoic acid methyl ester; the 0.1 kg of butyric anhydride added in step 1 is replaced by 0.15 kg of butyric anhydride; and the 0.03 kg of 3,6-dioxa-1,8-dithiol added in step 2 is replaced by 0.05 kg of 3,6-dioxa-1,8-dithiol.

[0046] Preparation Example 7

[0047] The difference between Preparation Example 7 and Preparation Example 1 is that the 0.4 kg of 10-undecenoic acid methyl ester added in step 1 is replaced by 0.45 kg of 10-undecenoic acid methyl ester; the 0.1 kg of butyric anhydride added in step 1 is replaced by 0.15 kg of butyric anhydride; and the 0.03 kg of 3,6-dioxa-1,8-dithiol added in step 2 is replaced by 0.04 kg of 3,6-dioxa-1,8-dithiol.

[0048] Preparation Example 8

[0049] The preparation of modified composite calcium carbonate comprises the following steps:

[0050] Weigh 0.4 kg of nano calcium carbonate and 0.6 kg of light calcium carbonate into a blender, mix and stir for 20 minutes at a speed of 300 rpm, then add 2 L of distilled water, and after ultrasonic treatment with an ultrasonic disperser for 30 minutes, heat the temperature to 80°C and continue stirring at a speed of 400 rpm, then add 0.025 kg of stearic acid, react for 2 hours, and after the reaction is completed, filter with a circulating water pump, and then repeatedly wash the filter cake with anhydrous ethanol to remove unreacted stearic acid and replace water. Finally, vacuum dry in a vacuum dryer at 100°C for 24 hours, and obtain modified composite calcium carbonate after grinding.

[0051] Preparation Example 9

[0052] The difference between Preparation Example 9 and Preparation Example 8 is that 0.4 kg of nano-calcium carbonate and 0.6 kg of light calcium carbonate are added instead of 0.8 kg of nano-calcium carbonate and 0.2 kg of light calcium carbonate.

[0053] Preparation Example 10

[0054] The difference between Preparation Example 10 and Preparation Example 8 is that the 0.4 kg of nano-calcium carbonate and 0.6 kg of light calcium carbonate are replaced by 0.6 kg of nano-calcium carbonate and 0.4 kg of light calcium carbonate.

[0055] Example

[0056] Example 1

[0057] A silane-modified sealant for ballastless track caulking is prepared from the following raw materials in parts by weight: 1 kg of a silane-modified polymer, 0.6 kg of diisodecyl phthalate, 1.5 kg of a filler, 0.02 kg of a thixotropic agent, 0.03 kg of an anti-ultraviolet agent, 0.03 kg of a light stabilizer, 0.03 kg of a heat stabilizer, 0.05 kg of a water scavenger, 0.05 kg of a silane coupling agent, 0.05 kg of a curing agent, and 0.02 kg of a curing accelerator.

[0058] A method for preparing a silane-modified sealant for ballastless track caulking comprises the following steps:

[0059] Step 1: Add 0.05 g of curing agent and 0.02 kg of curing accelerator into a stirrer and mix at a speed of 300 rpm for 1 hour for activation reaction, and set aside; heat 0.5 kg of the modified composite calcium carbonate in Preparation Example 8 in a heating press at a temperature of 440 ° C and a pressure of 0.15 MPa for 1 hour, and set aside;

[0060] Step 2: 1 kg of silane-modified polymer SX5830E, 0.6 kg of diisodecyl phthalate, 0.5 kg of the modified composite calcium carbonate after heating and pressurization in step 1, 1 kg of carbon black, 0.02 kg of the thixotropic agent in Preparation Example 1, 0.03 kg of ultraviolet absorber UV326, 0.03 kg of light stabilizer 292, and 0.03 kg of heat stabilizer 245 were added to a high-speed stirrer and mixed at a high speed of 800 rpm, and vacuumed for 60 min, and then The temperature was heated to 110°C, and the speed was reduced to 400 rpm for 120 min. The temperature was then reduced to 45°C, and 0.05 kg of dehydrating agent A-171 was added. The speed was then reduced to 250 rpm for 20 min. 0.05 kg of γ-aminopropyltrimethoxysilane was then added, and the speed was maintained at 250 rpm for 25 min. Finally, the curing agent and curing accelerator after the activation reaction in step 1 were added, and the speed was maintained at 250 rpm for 25 min to obtain the product.

[0061] Example 2

[0062] The difference between Example 2 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by 0.7 kg of modified composite calcium carbonate in Preparation Example 8; the 0.6 kg of diisodecyl phthalate, 0.5 kg of the modified composite calcium carbonate heated and pressurized in step 1, and 1 kg of carbon black added in step 2 are replaced by 1 kg of diisodecyl phthalate and 0.7 kg of the modified composite calcium carbonate heated and pressurized in step 1, and 1.4 kg of carbon black.

[0063] Example 3

[0064] The difference between Example 3 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate in Preparation Example 8 treated; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.63 kg of the modified composite calcium carbonate heated and pressurized in step 1 and 1.27 kg of carbon black.

[0065] Example 4

[0066] The difference between Example 4 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate in Preparation Example 9 treated; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.63 kg of the modified composite calcium carbonate heated and pressurized in step 1 and 1.27 kg of carbon black.

[0067] Example 5

[0068] The difference between Example 5 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate in Preparation Example 10 treated; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.63 kg of the modified composite calcium carbonate heated and pressurized in step 1 and 1.27 kg of carbon black.

[0069] Example 6

[0070] The difference between Example 6 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate in Preparation Example 10 treated; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.38 kg of the modified composite calcium carbonate heated and pressurized in step 1 and 1.52 kg of carbon black.

[0071] Example 7

[0072] The difference between Example 7 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate in Preparation Example 10 treated; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.475 kg of the modified composite calcium carbonate heated and pressurized in step 1 and 1.425 kg of carbon black.

[0073] Example 8

[0074] The difference between Example 8 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate in Preparation Example 10; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.475 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1.425 kg of carbon black; the 0.02 kg of thixotropic agent in Preparation Example 1 in step 2 is replaced by 0.02 kg of the thixotropic agent in Preparation Example 2.

[0075] Example 9

[0076] The difference between Example 9 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate treated in Preparation Example 10; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.475 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1.425 kg of carbon black; the 0.02 kg of thixotropic agent in Preparation Example 1 in step 2 is replaced by 0.02 kg of the thixotropic agent in Preparation Example 3.

[0077] Example 10

[0078] The difference between Example 10 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate treated in Preparation Example 10; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.475 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1.425 kg of carbon black; the 0.02 kg of thixotropic agent in Preparation Example 1 in step 2 is replaced by 0.02 kg of the thixotropic agent in Preparation Example 4.

[0079] Example 11

[0080] The difference between Example 11 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate treated in Preparation Example 10; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.475 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1.425 kg of carbon black; the 0.02 kg of thixotropic agent in Preparation Example 1 in step 2 is replaced by 0.02 kg of the thixotropic agent in Preparation Example 5.

[0081] Example 12

[0082] The difference between Example 12 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate treated in Preparation Example 10; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.475 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1.425 kg of carbon black; the 0.02 kg of thixotropic agent in Preparation Example 1 in step 2 is replaced by 0.02 kg of the thixotropic agent in Preparation Example 6.

[0083] Example 13

[0084] The difference between Example 13 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate treated in Preparation Example 10; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.475 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1.425 kg of carbon black; the 0.02 kg of thixotropic agent in Preparation Example 1 in step 2 is replaced by 0.02 kg of the thixotropic agent in Preparation Example 7.

[0085] Example 14

[0086] The difference between Example 14 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate in Preparation Example 10; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.475 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1.425 kg of carbon black; the 0.02 kg of thixotropic agent in Preparation Example 1 in step 2 is replaced by 0.1 kg of the thixotropic agent in Preparation Example 7.

[0087] Example 15

[0088] The difference between Example 15 and Example 1 is that the 0.5 kg of modified composite calcium carbonate in Preparation Example 8 treated in step 1 is replaced by the 0.63 kg of modified composite calcium carbonate in Preparation Example 10; the 0.6 kg of diisodecyl phthalate and 0.5 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1 kg of carbon black added in step 2 are replaced by 0.8 kg of diisodecyl phthalate and 0.475 kg of the modified composite calcium carbonate heated and pressurized in Step 1 and 1.425 kg of carbon black; the 0.02 kg of thixotropic agent in Preparation Example 1 in step 2 is replaced by 0.06 kg of the thixotropic agent in Preparation Example 7.

[0089] Comparative Example

[0090] Comparative Example 1

[0091] The difference between Comparative Example 1 and Example 1 is that the modified composite calcium carbonate in Preparation Example 8 was not subjected to heating and pressurization treatment.

[0092] Comparative Example 2

[0093] The difference between Comparative Example 2 and Example 1 is that 0.5 kg of light calcium carbonate is added instead of 0.5 kg of the modified composite calcium carbonate in Preparation Example 8.

[0094] Comparative Example 3

[0095] The difference between Comparative Example 3 and Example 1 is that the thixotropic agent of Preparation Example 1 added in step 2 is replaced by a polyamide wax thixotropic agent.

[0096] Comparative Example 4

[0097] The difference between Comparative Example 4 and Example 1 is that the thixotropic agent of Preparation Example 1 added in step 2 is replaced by hydrogenated castor oil.

[0098] Performance testing

[0099] Sample preparation:

[0100] 1. Class A samples: According to the standard of GB / T 16777-2008, samples of Examples 1-15 and Comparative Examples 1-4 were prepared. Class A samples were used to test elastic recovery rate, tensile modulus, tensile strength and elongation at break;

[0101] 2. Class B samples: Samples of Examples 1-15 and Comparative Examples 1-4 were prepared according to GB / T 13477-2002. Class B samples were used to test the adhesion at fixed extension, the failure area of ​​the bond with concrete, the adhesion after cold drawing and hot pressing, and the adhesion after tension-compression cycles.

[0102] 3. Testing standards: Various performance tests were performed on the Class A samples and Class B samples prepared in Examples 1-15 and Comparative Examples 1-4 in accordance with the Chinese Railway Standard Q-CR 601-2017 Railway Ballastless Track Caulking Materials.

[0103] Table 1 Performance test of Examples 1-3

[0104]

[0105]

[0106] Table 2 Performance test of Examples 4-7 and Comparative Examples 1-2

[0107]

[0108]

[0109]

[0110] Table 3 Performance Tests of Examples 8-13

[0111]

[0112]

[0113] Table 4 Performance test of Examples 14-15 and Comparative Examples 3-4

[0114]

[0115]

[0116]

[0117] From Examples 1-3 and Table 1, it can be seen that when the addition amounts of diisodecyl phthalate and filler are different, the effects on the sealant's surface drying time, elastic recovery rate, tensile modulus, tensile strength, elongation at break, fixed extension adhesion, concrete bond failure area, adhesion after cold drawing-hot pressing, and adhesion after tension-compression cycles are all different. When the ratio of filler and diisodecyl phthalate is optimal, the two have a better improvement effect. Taking all factors into consideration, the ratio of filler and diisodecyl phthalate in Example 3 is optimal.

[0118] From Examples 4-7 and Comparative Examples 1-2 and Table 2, it can be seen that when the ratio of nano-calcium carbonate and light calcium carbonate in the modified composite calcium carbonate and the ratio of modified composite calcium carbonate and carbon black are different, the effects on the surface drying time, elastic recovery rate, tensile modulus, tensile strength, elongation at break, constant extension adhesion, bonding failure area with concrete, adhesion after cold drawing-hot pressing, and adhesion after tension-compression cycle of the sealant are all different. According to the comparative example, it can be seen that the modified composite calcium carbonate that has not been heated and pressurized and the light calcium carbonate added alone have a weaker effect on improving the performance of the sealant than the present application. It can be seen that compounding and modifying nano-calcium carbonate and light calcium carbonate, and then heating and pressurizing them and compounding them with carbon black as a filler have significantly improved the various properties of the sealant.

[0119] In combination with Examples 8-15 and Comparative Examples 3-4 and Table 3-4, it can be seen that in the thixotropic agent, when the ratio of each component for preparing the functional polyamide and the ratio of the functional polyamide to 3,6-dioxa-1,8-dithiol are different, the effects on the surface drying time, elastic recovery rate, tensile modulus, tensile strength, elongation at break, fixed extension adhesion, bonding failure area with concrete, adhesion after cold drawing-hot pressing, and adhesion after tension-compression cycle of the sealant are all different. The amount of thixotropic agent added also has different effects on the overall performance of the sealant. According to the comparative example, when the thixotropic agent is used exclusively as a conventional thixotropic agent, the effect of improving the performance of the sealant is weaker than that of the present application. It can be seen that the thixotropic agent of the present application has a significant improvement on the various properties of the sealant.

[0120] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A silane-modified sealant for ballastless track caulking, characterized in that: The invention is prepared by the following raw materials in parts by weight: 80-120 parts of silane modified polymer, 60-100 parts of plasticizer, 150-210 parts of filler, 2-10 parts of thixotropic agent, 0.5-3 parts of anti-ultraviolet agent, 0.5-3 parts of light stabilizer, 0.5-3 parts of heat stabilizer, 3-6 parts of water scavenger, 3-6 parts of silane coupling agent, 3-7 parts of curing agent and 1-3 parts of curing accelerator. The silane-modified polymer includes one or more combinations of S327, S203, S801, SAX510, SX5830E, and S888E; the thixotropic agent includes functional polyamide, 3,6-dioxa-1,8-dithiol, and azobisisobutyronitrile; and the mass ratio of the functional polyamide, 3,6-dioxa-1,8-dithiol, and azobisisobutyronitrile is 1:0.3-0.5:0.

01. The functional polyamide comprises 1,3-diamino-2-propanol, 10-undecenoic acid methyl ester, butyric anhydride and 4-dimethylaminopyridine, wherein the mass ratio of the 1,3-diamino-2-propanol, 10-undecenoic acid methyl ester, butyric anhydride and 4-dimethylaminopyridine is 1:4-5:1-2:0.03; The preparation of the thixotropic agent comprises the following steps: Step 1: Add accurately measured 1,3-diamino-2-propanol and 10-undecenoic acid methyl ester to anhydrous tetrahydrofuran, heat to 60-70°C, continue stirring, and react for 22-26 hours; then add accurately measured butyric anhydride and 4-dimethylaminopyridine, change the temperature to 55-65°C, continue stirring, and continue reacting for 22-26 hours. After the reaction is completed, add deionized water, dry over anhydrous magnesium sulfate, and then dry at 100-110°C for 1-2 hours to obtain a functional polyamide; Step 2: Add accurately measured amounts of functional polyamide, 3,6-dioxa-1,8-dithiol, and azobisisobutyronitrile to anhydrous tetrahydrofuran and mix evenly. Heat to 60-70°C, continue stirring, and react for 22-26 hours. After the reaction is complete, add methanol, take the precipitate, and then dry it at 40-50°C for 3-5 hours to prepare a thixotropic agent. The filler is composed of modified composite calcium carbonate and carbon black, wherein the modified composite calcium carbonate includes nano calcium carbonate, light calcium carbonate and stearic acid, the mass ratio of the nano calcium carbonate, light calcium carbonate and stearic acid is 2-4:1-3:0.25, and the mass ratio of the modified composite calcium carbonate and carbon black is 1:2-4; the filler is pressurized and heated at a temperature of 400-450°C, a pressure of 0.1-0.2MPa, and a time of 0.1-1.5h.

2. The silane-modified sealant for ballastless track caulking according to claim 1, characterized in that: The plasticizer includes one or more of diisononyl phthalate, diisooctyl phthalate, diisodecyl phthalate, PPG1000, PPG2000, PPG3000, PPG4000 and PPG8000; the mass ratio of the filler to the plasticizer is 15-21:6-10.

3. The silane-modified sealant for ballastless track caulking according to claim 1, characterized in that: The heat stabilizer includes one or more combinations of antioxidant 1076, antioxidant 245, antioxidant Irgafos168 and antioxidant Topanol; the light stabilizer is one or more combinations of light stabilizer 292, light stabilizer 770, light stabilizer 765, light stabilizer 622 and light stabilizer 5050H; and the anti-ultraviolet agent is a benzotriazole ultraviolet absorber.

4. The silane-modified sealant for ballastless track caulking according to claim 1, characterized in that: The silane coupling agent includes 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, phenylamino-silane, triaminosilane, γ-mercaptopropyltrimethoxysilane, γ-ureapropyltrimethoxysilane, γ-ureapropyltriethoxysilane and γ-methacryloxypropyltrimethoxysilane.

5. The method for preparing a silane-modified sealant for ballastless track caulking according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: Mix the curing agent and curing accelerator in accurate amounts and stir evenly. After stirring evenly, activate the reaction for 1-1.5 hours and set aside. Step 2: Mix the accurately measured silane-modified polymer, plasticizer, filler, thixotropic agent, anti-ultraviolet agent, light stabilizer, and heat stabilizer at a high speed and stir at a speed of 600-800 rpm, and perform vacuum treatment for 60-70 minutes, then heat the temperature to 100-120°C, and reduce the speed to 300-600 rpm for 110-130 minutes, then reduce the temperature to 40-50°C, add the accurately measured dehydrating agent, and then reduce the speed to 200-300 rpm for 15-25 minutes, then add the accurately measured silane coupling agent, maintain the speed at 200-300 rpm for 20-30 minutes, and finally add the curing agent and curing accelerator after the activation reaction in step 1, maintain the speed at 200-300 rpm for 20-30 minutes to obtain the product.

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