Sealant for deformation joint and preparation method thereof

Abstract

The present invention relates to a sealant for a deformation joint and a preparation method thereof, and relates to the technical field of materials, the sealant for the deformation joint comprises the following components by weight: 115-130 parts of a base material, 8-20 parts of a composite filler, 0.5-2 parts of a catalyst and 1-10 parts of a coupling agent, the base material is prepared from alpha, omega-dihydroxy polydimethylsiloxane and a fluorine-containing imidazole ionic liquid compound; the composite filler is prepared from pyrophyllite and molybdenum disulfide as raw materials. The seal for the deformation joint provided by the invention has excellent low temperature resistance and oil resistance, can be widely applied to caulking sealing of deformation joints of urban underground comprehensive pipe galleries, subways, expressways and the like, and particularly can meet the use requirements of special environments such as fuel oil polluted and low-temperature regions and the like; the application range of the existing silicone sealant is further widened.

Description

Technical Field

[0001] The invention relates to the technical field of materials, and in particular to a sealant for a deformation joint and a preparation method thereof. Background Art

[0002] Sealant is a paste-like material used to fill holes, joints and other gaps. After curing, it bonds the base material into a whole. It has functions such as waterproof, dustproof and fogproof. It is widely used in urban underground comprehensive pipeline corridors, subways, highways, bridges, airport runways and high-speed railway tracks. It plays a role of waterproofing and sealing while coordinating the expansion and deformation of concrete, fully ensuring the smoothness and stability of the overall concrete structure.

[0003] At present, the existing caulking materials mainly include asphalt sealing materials, polysulfide sealants, silicone sealants and polyurethane sealants. In the early days, the caulking materials were mainly asphalt sealing materials and polyurethane sealants, but their high and low temperature resistance and weather resistance were poor, and their performance declined seriously within a few years. Now they have been replaced by silicone caulking materials. However, the low temperature resistance and oil resistance of existing silicone sealants need to be further improved to meet the use requirements in special environments such as fuel pollution and low temperature areas. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a sealant for expansion joints and a preparation method thereof.

[0005] In a first aspect, the present invention provides a sealant for a deformation joint, wherein the sealant for the deformation joint comprises the following components in parts by weight:

[0006] 115-130 parts of base material, 8-20 parts of composite filler, 0.5-2 parts of catalyst and 1-10 parts of coupling agent;

[0007] The base material is composed of α,ω-dihydroxy polydimethylsiloxane and fluorine-containing imidazole ionic liquid compound;

[0008] The composite filler is prepared by taking pyrophyllite and molybdenum disulfide as raw materials.

[0009] Furthermore, the sealant for the expansion joint comprises the following components in parts by weight:

[0010] 120 parts of sealant, 15.5 parts of composite filler, 1 part of catalyst and 5 parts of coupling agent.

[0011] Furthermore, the weight ratio of the α,ω-dihydroxypolydimethylsiloxane to the fluorine-containing imidazole ionic liquid compound is 100:(9-13).

[0012] Furthermore, the fluorine-containing imidazole ionic liquid compound includes at least one of 1-ethyl-3-methylimidazolium trifluoromethylsulfonate, 1-hexyl-3-methylimidazolium trifluoromethylsulfonate and 1-butyl-3-methylimidazolium trifluoromethylsulfonate.

[0013] Furthermore, the preparation method of the composite filler includes the following process:

[0014] Pulverizing pyrophyllite and molybdenum disulfide to obtain a mixed powder;

[0015] The mixed powder is added into anhydrous ethanol and stirred, and then a silane coupling agent is added and stirred continuously to obtain a mixed slurry;

[0016] The pH of the mixed slurry is adjusted to 4.5-5.5, and then microwave irradiation is performed, followed by filtration, and the obtained filter cake is dried and crushed to obtain the composite filler.

[0017] Furthermore, the weight ratio of the pyrophyllite, the molybdenum disulfide and the silane coupling agent is (1-2):(1-2):(0.01-0.05); in terms of weight percentage, the solid content of the mixed slurry is 30-45%.

[0018] Furthermore, the working parameters of the microwave irradiation include: microwave power of 70 to 100 W, and microwave irradiation time of 20 to 45 minutes.

[0019] Furthermore, the catalyst is an organic tin compound, and the coupling agent is a titanate coupling agent.

[0020] In a second aspect, the present invention provides a method for preparing a sealant for a deformation joint according to any one of the first aspects, the preparation method comprising the following steps:

[0021] Obtaining the base material;

[0022] Obtaining the composite filler;

[0023] The base material, the composite filler, the catalyst and the coupling agent are mixed by vacuum stirring to obtain the sealant for the expansion joint.

[0024] Furthermore, the working parameters of the vacuum stirring and mixing include: a temperature of 55 to 60° C., a stirring time of 3 to 6 hours, and a pressure of -0.04 to -0.08 MPa.

[0025] The above technical solution provided by the present invention has at least the following advantages compared with the prior art:

[0026] The invention provides a sealant for expansion joints. On the one hand, the invention introduces a fluorine-containing imidazole ionic liquid compound as a base material into α, ω-dihydroxy polydimethylsiloxane, and on the other hand, adds a composite filler prepared from pyrophyllite and molybdenum disulfide as raw materials for reinforcement and modification. The two cooperate with each other to jointly prepare a sealant with excellent low-temperature resistance and excellent oil resistance. The sealant can be widely used in caulking and sealing of expansion joints in urban underground comprehensive pipe galleries, subways, highways, etc., and can especially meet the use requirements of special environments such as fuel pollution and low-temperature areas, further broadening the scope of application of existing silicone sealants. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0028] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0029] Figure 1 The present invention is a schematic flow chart of a method for preparing a sealant for expansion joints provided by the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0032] In a first aspect, the present invention provides a sealant for a deformation joint, wherein the sealant for the deformation joint comprises the following components in parts by weight:

[0033] 115-130 parts of base material, 8-20 parts of composite filler, 0.5-2 parts of catalyst and 1-10 parts of coupling agent;

[0034] The base material is composed of α,ω-dihydroxy polydimethylsiloxane and fluorine-containing imidazole ionic liquid compound;

[0035] The composite filler is prepared by taking pyrophyllite and molybdenum disulfide as raw materials.

[0036] The invention provides a sealant for expansion joints. On the one hand, the invention introduces a fluorine-containing imidazole ionic liquid compound as a base material into α, ω-dihydroxy polydimethylsiloxane, and on the other hand, adds a composite filler prepared from pyrophyllite and molybdenum disulfide as raw materials for reinforcement and modification. The two cooperate with each other to jointly prepare a sealant with excellent low-temperature resistance and excellent oil resistance. The sealant can be widely used in caulking and sealing of expansion joints in urban underground comprehensive pipe galleries, subways, highways, etc., and can especially meet the use requirements of special environments such as fuel pollution and low-temperature areas, further broadening the scope of application of existing silicone sealants.

[0037] In some specific embodiments, the sealant for the expansion joint includes the following components in parts by weight:

[0038] 120 parts of sealant, 15.5 parts of composite filler, 1 part of catalyst and 5 parts of coupling agent.

[0039] In some specific embodiments, the weight ratio of the α,ω-dihydroxypolydimethylsiloxane to the fluorine-containing imidazole ionic liquid compound is 100:(9-13); preferably 100:11.5.

[0040] In some specific embodiments, the fluorine-containing imidazolium ionic liquid compound includes at least one of 1-ethyl-3-methylimidazolium trifluoromethylsulfonate, 1-hexyl-3-methylimidazolium trifluoromethylsulfonate and 1-butyl-3-methylimidazolium trifluoromethylsulfonate.

[0041] In some specific embodiments, the method for preparing the composite filler comprises the following process:

[0042] Pulverizing pyrophyllite and molybdenum disulfide to obtain a mixed powder;

[0043] The mixed powder is added into anhydrous ethanol and stirred, and then a silane coupling agent is added and stirred continuously to obtain a mixed slurry;

[0044] The pH of the mixed slurry is adjusted to 4.5-5.5, and then microwave irradiation is performed, followed by filtration, and the obtained filter cake is dried and crushed to obtain the composite filler.

[0045] In some specific embodiments, dilute hydrochloric acid with a weight percentage of 2-4% is used to adjust the pH.

[0046] In some specific embodiments, microwave irradiation can be performed using existing equipment such as existing microwave reactors.

[0047] In some specific embodiments, the particle size of the composite filler is 100-200 mesh.

[0048] In some specific embodiments, the silane coupling agent can be directly selected from commercially available silane coupling agent KH-550, silane coupling agent KH-560, etc.

[0049] In some specific embodiments, the weight ratio of the talc, the molybdenum disulfide and the silane coupling agent is (1-2):(1-2):(0.01-0.05), preferably 1:1:0.2; in terms of weight percentage, the solid content of the mixed slurry is 30-45%, preferably 35%.

[0050] In some specific embodiments, the working parameters of the microwave irradiation include: microwave power of 70 to 100 W, preferably 85 W; microwave irradiation time of 20 to 45 minutes, preferably 30 minutes.

[0051] In some specific embodiments, the catalyst is an organic tin compound, such as dibutyltin dilaurate, etc.; the coupling agent is a titanate coupling agent, such as commercially available titanate coupling agent 201, etc.

[0052] In a second aspect, based on a general inventive concept, the present invention provides a method for preparing a sealant for a deformation joint as described in any one of the first aspects, such as Figure 1 As shown, the preparation method comprises the following steps:

[0053] Obtaining the base material;

[0054] Obtaining the composite filler;

[0055] The base material, the composite filler, the catalyst and the coupling agent are mixed by vacuum stirring to obtain the sealant for the expansion joint.

[0056] The preparation method of the sealant for the expansion joint provided by the present invention is simple to operate, does not require additional specific equipment, and is suitable for mass industrial production.

[0057] In some specific embodiments, the working parameters of the vacuum stirring and mixing include: a temperature of 55 to 60° C., a stirring time of 3 to 6 hours, and a pressure of -0.04 to -0.08 MPa.

[0058] In some specific embodiments, the step of obtaining the base material includes the following process: stirring α, ω-dihydroxy polydimethylsiloxane and a fluorinated imidazole ionic liquid compound at -0.05 to -0.08 MPa and 100 to 110° C. for 0.5 to 1.5 hours, and then cooling to obtain the base material.

[0059] It should be noted that, in the sealant for expansion joints provided by the present invention and the preparation method thereof, the raw materials involved, unless otherwise specified or limited, the raw materials used, such as α, ω-dihydroxypolydimethylsiloxane (CAS: 31692-79-2), catalysts, coupling agents, fluorinated imidazole ionic liquid compounds, pyrophyllite and molybdenum disulfide, etc., can all be commercially available products; at the same time, the process steps and parameters involved can be carried out according to the existing sealant preparation process or using existing equipment in a conventional operating manner.

[0060] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0061] Example 1

[0062] This example provides a sealant for expansion joints, which includes the following components in parts by weight: 120 parts of sealant, 15.5 parts of composite filler, 1 part of catalyst and 5 parts of coupling agent; wherein the base material is composed of α,ω-dihydroxypolydimethylsiloxane and fluorine-containing imidazole ionic liquid compound in a weight ratio of 100:11.5; the composite filler is prepared using pyrophyllite and molybdenum disulfide as raw materials; the fluorine-containing imidazole ionic liquid compound is 1-ethyl-3-methylimidazole trifluoromethylsulfonate, the catalyst is dibutyltin dilaurate, and the coupling agent is titanate coupling agent 201.

[0063] The preparation method of the sealant for the expansion joint comprises the following steps:

[0064] Step (1): stirring α,ω-dihydroxy polydimethylsiloxane and a fluorine-containing imidazole ionic liquid compound at a pressure of -0.07 MPa and a temperature of 105° C. for 1 hour, and then cooling to obtain the base material;

[0065] Step (2): pulverizing pyrophyllite and molybdenum disulfide to obtain a mixed powder; adding the mixed powder into anhydrous ethanol and stirring, and then adding silane coupling agent KH-550 and continuing to stir to obtain a mixed slurry; using 3% by weight of dilute hydrochloric acid to adjust the pH of the mixed slurry to 5.0, and then adding it into a microwave reactor for microwave irradiation, and then filtering and drying, pulverizing, and sieving the obtained filter cake to obtain a composite filler with a mesh size of 100 to 200 meshes; wherein the weight ratio of the pyrophyllite, the molybdenum disulfide and the silane coupling agent KH-550 is 1:1:0.2; in terms of weight percentage, the solid content of the mixed slurry is 35%; the working parameters of the microwave irradiation include: microwave power of 85W; microwave irradiation time of 30 minutes;

[0066] Step (3): at a pressure of -0.06 MPa and a temperature of 58° C., the base material obtained in step (1), the composite filler obtained in step (2), the catalyst and the coupling agent are mixed by vacuum stirring for 4 hours to obtain the sealant for the deformation joint.

[0067] Example 2

[0068] This example provides a sealant for expansion joints, which includes the following components in parts by weight: 115 parts of sealant, 8 parts of composite filler, 0.5 parts of catalyst and 3 parts of coupling agent; wherein the base material is composed of α, ω-dihydroxypolydimethylsiloxane and fluorine-containing imidazole ionic liquid compound in a weight ratio of 100:9; the composite filler is prepared using pyrophyllite and molybdenum disulfide as raw materials; the fluorine-containing imidazole ionic liquid compound is 1-hexyl-3-methylimidazole trifluoromethylsulfonate, the catalyst is dibutyltin dilaurate, and the coupling agent is titanate coupling agent 201.

[0069] The preparation method of the sealant for the expansion joint comprises the following steps:

[0070] Step (1): stirring α,ω-dihydroxy polydimethylsiloxane and a fluorine-containing imidazole ionic liquid compound at a pressure of -0.07 MPa and a temperature of 105° C. for 1 hour, and then cooling to obtain the base material;

[0071] Step (2): pulverizing pyrophyllite and molybdenum disulfide to obtain a mixed powder; adding the mixed powder into anhydrous ethanol and stirring, and then adding silane coupling agent KH-550 and continuing to stir to obtain a mixed slurry; using 3% by weight of dilute hydrochloric acid to adjust the pH of the mixed slurry to 5.0, and then adding it into a microwave reactor for microwave irradiation, and then filtering and drying, pulverizing and sieving the obtained filter cake to obtain a composite filler with a mesh size of 100 to 200 meshes; wherein the weight ratio of the pyrophyllite, the molybdenum disulfide and the silane coupling agent KH-550 is 1:1:0.2; in terms of weight percentage, the solid content of the mixed slurry is 35%; the working parameters of the microwave irradiation include: microwave power of 70W; microwave irradiation time of 45 minutes;

[0072] Step (3): at a pressure of -0.06 MPa and a temperature of 58° C., the base material obtained in step (1), the composite filler obtained in step (2), the catalyst and the coupling agent are mixed by vacuum stirring for 4 hours to obtain the sealant for the deformation joint.

[0073] Example 3

[0074] This example provides a sealant for expansion joints, which includes the following components in parts by weight: 130 parts of sealant, 20 parts of composite filler, 2 parts of catalyst and 10 parts of coupling agent; wherein the base material is composed of α, ω-dihydroxypolydimethylsiloxane and fluorine-containing imidazole ionic liquid compound in a weight ratio of 100:13; the composite filler is prepared using pyrophyllite and molybdenum disulfide as raw materials; the fluorine-containing imidazole ionic liquid compound is 1-butyl-3-methylimidazole trifluoromethylsulfonate, the catalyst is dibutyltin dilaurate, and the coupling agent is titanate coupling agent 201.

[0075] The preparation method of the sealant for the expansion joint comprises the following steps:

[0076] Step (1): stirring α,ω-dihydroxy polydimethylsiloxane and a fluorine-containing imidazole ionic liquid compound at a pressure of -0.07 MPa and a temperature of 105° C. for 1 hour, and then cooling to obtain the base material;

[0077] Step (2): pulverizing pyrophyllite and molybdenum disulfide to obtain a mixed powder; adding the mixed powder into anhydrous ethanol and stirring, then adding silane coupling agent KH-550 and continuing to stir to obtain a mixed slurry; adjusting the pH of the mixed slurry to 5.0 with 3% by weight of dilute hydrochloric acid, then adding the mixed slurry into a microwave reactor for microwave irradiation, then filtering and drying, pulverizing and sieving the obtained filter cake to obtain a composite filler with a mesh size of 100 to 200 meshes; wherein the weight ratio of the pyrophyllite, the molybdenum disulfide and the silane coupling agent KH-550 is 1:1:0.2; in terms of weight percentage, the solid content of the mixed slurry is 35%; the working parameters of the microwave irradiation include: microwave power of 100 W; microwave irradiation time of 20 minutes;

[0078] Step (3): at a pressure of -0.06 MPa and a temperature of 58° C., the base material obtained in step (1), the composite filler obtained in step (2), the catalyst and the coupling agent are mixed by vacuum stirring for 4 hours to obtain the sealant for the deformation joint.

[0079] Comparative Example 1

[0080] This example provides a sealant for expansion joints and a preparation method thereof, which is different from Example 1 only in that 1-ethyl-3-methylimidazolium trifluoromethanesulfonate is adjusted to tetraethylammonium trifluoromethanesulfonate; the remaining steps and parameters are the same.

[0081] Comparative Example 2

[0082] This example provides a sealant for expansion joints and a preparation method thereof, which differs from Example 1 only in that the amount of molybdenum disulfide is adjusted to 0 (i.e., the composite filler is composed only of pyrophyllite); the remaining steps and parameters are the same. The details are as follows:

[0083] This example provides a sealant for expansion joints, which includes the following components in parts by weight: 120 parts of sealant, 15.5 parts of filler, 1 part of catalyst and 5 parts of coupling agent; wherein the base material is composed of α,ω-dihydroxypolydimethylsiloxane and fluorinated imidazole ionic liquid compound in a weight ratio of 100:11.5; the filler is prepared using pyrophyllite as raw material; the fluorinated imidazole ionic liquid compound is 1-ethyl-3-methylimidazolium trifluoromethylsulfonate, the catalyst is dibutyltin dilaurate, and the coupling agent is titanate coupling agent 201.

[0084] The preparation method of the sealant for the expansion joint comprises the following steps:

[0085] Step (1): stirring α,ω-dihydroxy polydimethylsiloxane and a fluorine-containing imidazole ionic liquid compound at a pressure of -0.07 MPa and a temperature of 105° C. for 1 hour, and then cooling to obtain the base material;

[0086] Step (2): crushing pyrophyllite to obtain a powder; adding the powder to anhydrous ethanol and stirring, then adding a silane coupling agent KH-550 and continuing to stir to obtain a mixed slurry; using 3% by weight of dilute hydrochloric acid to adjust the pH of the mixed slurry to 5.0, then adding it to a microwave reactor for microwave irradiation, then filtering and drying, crushing and sieving the obtained filter cake to obtain a filler with a mesh size of 100 to 200 meshes; wherein the weight ratio of the pyrophyllite to the silane coupling agent KH-550 is 1:0.2; in terms of weight percentage, the solid content of the mixed slurry is 35%; the working parameters of the microwave irradiation include: microwave power of 85W; microwave irradiation time of 30 minutes;

[0087] Step (3): at a pressure of -0.06 MPa and a temperature of 58° C., the base material obtained in step (1), the filler obtained in step (2), the catalyst and the coupling agent are mixed by vacuum stirring for 4 hours to obtain the sealant for the deformation joint.

[0088] Comparative Example 3

[0089] This example provides a sealant for expansion joints and a preparation method thereof, which differs from Example 1 only in that the amount of pyrophyllite is adjusted to 0 (i.e., the composite filler is composed only of molybdenum disulfide); the remaining steps and parameters are the same. The details are as follows:

[0090] This example provides a sealant for expansion joints, which includes the following components in parts by weight: 120 parts of sealant, 15.5 parts of filler, 1 part of catalyst and 5 parts of coupling agent; wherein the base material is composed of α,ω-dihydroxypolydimethylsiloxane and fluorinated imidazole ionic liquid compound in a weight ratio of 100:11.5; the filler is prepared using molybdenum disulfide as a raw material; the fluorinated imidazole ionic liquid compound is 1-ethyl-3-methylimidazolium trifluoromethylsulfonate, the catalyst is dibutyltin dilaurate, and the coupling agent is titanate coupling agent 201.

[0091] The preparation method of the sealant for the expansion joint comprises the following steps:

[0092] Step (1): stirring α,ω-dihydroxy polydimethylsiloxane and a fluorine-containing imidazole ionic liquid compound at a pressure of -0.07 MPa and a temperature of 105° C. for 1 hour, and then cooling to obtain the base material;

[0093] Step (2): crushing molybdenum disulfide to obtain a powder; adding the powder to anhydrous ethanol and stirring, then adding a silane coupling agent KH-550 and continuing to stir to obtain a mixed slurry; using 3% by weight of dilute hydrochloric acid to adjust the pH of the mixed slurry to 5.0, then adding it to a microwave reactor for microwave irradiation, then filtering and drying, crushing and sieving the obtained filter cake to obtain a filler with a mesh size of 100 to 200 mesh; wherein the weight ratio of the molybdenum disulfide to the silane coupling agent KH-550 is 1:0.2; in terms of weight percentage, the solid content of the mixed slurry is 35%; the working parameters of the microwave irradiation include: microwave power of 85W; microwave irradiation time of 30 minutes;

[0094] Step (3): at a pressure of -0.06 MPa and a temperature of 58° C., the base material obtained in step (1), the filler obtained in step (2), the catalyst and the coupling agent are mixed by vacuum stirring for 4 hours to obtain the sealant for the deformation joint.

[0095] Test Case

[0096] In this example, the performance of the sealants for expansion joints provided in the embodiments and comparative examples is tested.

[0097] Test method: The sealant was tested for 100% tensile modulus (Mpa) at low temperature (-20°C) and fixed tensile adhesion (150%) at low temperature (-20°C) before and after immersion in 92# gasoline at 50°C and 50% relative humidity for 7 days according to GB / T 13477.8-2017 standard. The Shore A hardness tester was used to test the Shore hardness at low temperature (-20°C) according to GB / T 531-1999 standard. The test results are shown in Tables 1 and 2. Among them, the qualified standard of 100% tensile modulus (Mpa) at low temperature (-20°C) is ≤0.3Mpa, and the qualified standard of fixed tensile adhesion (150%) at low temperature (-20°C) is no damage. The lower the Shore hardness at low temperature (-20°C), the better the flexibility at low temperature.

[0098] Table 1 Partial performance test results of sealant before immersion in 92# gasoline

[0099]

[0100]

[0101] Table 2 Partial performance test results of sealant after soaking in 92# gasoline

[0102]

[0103] It can be seen from Table 1 and Table 2 that, compared with the comparative example, the sealant for expansion joints provided by the embodiment of the present invention has better low temperature resistance; at the same time, the performance retention rate after immersion in 92# gasoline is high, indicating that it has excellent oil resistance. In addition, the sealants provided by Examples 1 to 3 of the present invention are tested for basic properties such as tensile strength, maximum elongation, aging test, and fixed elongation adhesion with reference to GB / T 13477.8-2017 standard, and they also meet the qualified standards, such as tensile strength ≥ 3Mpa, elongation ≥ 1000, and excellent performance.

[0104] In summary, the present invention provides a sealant for expansion joints and a preparation method thereof. On the one hand, a fluorine-containing imidazole ionic liquid compound is introduced into α, ω-dihydroxy polydimethylsiloxane as a base material, and on the other hand, a composite filler prepared from pyrophyllite and molybdenum disulfide as raw materials is added for reinforcement and modification. The two work together to prepare a sealant with excellent low-temperature resistance and excellent oil resistance. The sealant can be widely used in caulking and sealing of expansion joints in urban underground integrated pipeline corridors, subways, highways, etc., especially can meet the use requirements of special environments such as fuel pollution and low-temperature areas, further broadening the scope of application of existing silicone sealants.

[0105] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0106] In the present invention, in the absence of contrary instructions, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of the present invention, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[0107] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A sealant for expansion joints, characterized in that: The sealant for the expansion joint comprises the following components in parts by weight: 115-130 parts of base material, 8-20 parts of composite filler, 0.5-2 parts of catalyst and 1-10 parts of coupling agent; The base material is composed of α,ω-dihydroxy polydimethylsiloxane and fluorine-containing imidazole ionic liquid compound; The composite filler is prepared by taking pyrophyllite and molybdenum disulfide as raw materials.

2. The sealant for expansion joint according to claim 1, characterized in that: The sealant for the expansion joint comprises the following components in parts by weight: 120 parts of sealant, 15.5 parts of composite filler, 1 part of catalyst and 5 parts of coupling agent.

3. The sealant for expansion joint according to claim 1 or 2, characterized in that: The weight ratio of the α,ω-dihydroxy polydimethylsiloxane to the fluorine-containing imidazole ionic liquid compound is 100:(9-13).

4. The sealant for expansion joint according to claim 1 or 2, characterized in that: The fluorine-containing imidazole ionic liquid compound includes at least one of 1-ethyl-3-methylimidazolium trifluoromethylsulfonate, 1-hexyl-3-methylimidazolium trifluoromethylsulfonate and 1-butyl-3-methylimidazolium trifluoromethylsulfonate.

5. The sealant for expansion joint according to claim 1 or 2, characterized in that: Preparation method of the composite filler The process includes: Pulverizing pyrophyllite and molybdenum disulfide to obtain a mixed powder; The mixed powder is added into anhydrous ethanol and stirred, and then a silane coupling agent is added and stirred continuously to obtain a mixed slurry; The pH of the mixed slurry is adjusted to 4.5-5.5, and then microwave irradiation is performed, followed by filtration, and the obtained filter cake is dried and crushed to obtain the composite filler.

6. The sealant for expansion joints according to claim 5, characterized in that: The weight ratio of the pyrophyllite, the molybdenum disulfide and the silane coupling agent is (1-2):(1-2):(0.01-0.05); in terms of weight percentage, the solid content of the mixed slurry is 30-45%.

7. The sealant for expansion joints according to claim 5, characterized in that: The working parameters of the microwave irradiation include: microwave power of 70 to 100 W, and microwave irradiation time of 20 to 45 minutes.

8. The sealant for expansion joints according to claim 1 or 2, characterized in that: The catalyst is an organic tin compound, and the coupling agent is a titanate coupling agent.

9. A method for preparing a sealant for expansion joints according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: Obtaining the base material; Obtaining the composite filler; The base material, the composite filler, the catalyst and the coupling agent are mixed by vacuum stirring to obtain the sealant for the expansion joint.

10. The method for preparing a sealant for a deformation joint according to claim 9, characterized in that: The working parameters of the vacuum stirring and mixing include: a temperature of 55 to 60° C., a stirring time of 3 to 6 hours, and a pressure of -0.04 to -0.08 MPa.

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