Two-component silicone sealant with long storage period and preparation method thereof

Abstract

The invention provides a bi-component silicone sealant with a long storage period and a preparation method thereof, and relates to the field of silicone sealant materials. The method comprises the following steps: preparing a component A from alpha, omega-dihydroxy polydimethylsiloxane, dimethyl silicone oil and a filler; the preparation method comprises the following steps: carrying out physical and chemical dual dehydration on alkoxy-terminated 107 glue, a filler and a dehydration material, and then carrying out pretreatment by using ketoxime siloxane to obtain a modified base material; pretreating a cross-linking agent, a coupling agent and a catalyst to obtain a mixed vulcanizing agent; preparing a component B from the improved base material, hydrophobic white carbon black and a mixed vulcanizing agent; the component A and the component B are mixed according to the volume ratio of (1-2): 1, and the two-component silicone sealant is prepared. The two-component silicone sealant disclosed by the invention does not have obvious thickening in a 12-month long-term storage process, can keep stable breaking time and vulcanization effect in a 12-month period of validity, and has very important significance on the scenes such as foreign trade, ocean transportation and the like which require long storage periods.

Description

Technical Field

[0001] The invention relates to the field of silicone sealant materials, and in particular to a two-component silicone sealant with a long storage period and a preparation method thereof. Background Art

[0002] Two-component silicone sealant contains component A and component B. The commonly used two-component ratios in the industry are 10:1, 6:1, 2:1, and 1:1 by volume. Among them, component A mainly contains 107 glue, silicone oil and filler, while component B has certain differences according to different mixing ratios. Component B with a volume ratio of 10:1 and 6:1 mainly contains silicone oil, filler, curing agent and catalyst. In order to consider factors such as strength and weather resistance, component B with a volume ratio of 2:1 or 1:1 mainly contains end-capped 107 glue, silicone oil, filler, curing agent and catalyst.

[0003] Two-component silicone sealant, due to its excellent rapid curing mechanism, is widely used in bonding scenarios such as insulating glass, photovoltaic frames, kitchen utensils, stoves, etc. where continuous operations and short turnaround times are required.

[0004] In practical applications, two-component silicone sealants with different ratios have their own advantages. Two-component silicone sealants with a volume ratio of 10:1 and 6:1 have advantages such as long storage time, high strength, and better weather resistance, but also have disadvantages such as large mixing ratio differences, high equipment precision requirements, expensive equipment, and poor resistance to mixing ratio fluctuations. Two-component silicone sealants with a volume ratio of 2:1 and 1:1 have advantages such as low equipment requirements and the ability to accommodate 10% to 20% mixing fluctuations, but in order to ensure strength and construction performance, the additive content of component B is lower and the filler content is higher. The moisture in the filler will cause problems such as thickening or curing failure of component B of the two-component silicone sealant during storage.

[0005] In summary, solving the storage period problem of component B in two-component silicone sealants with a volume ratio of 2:1 and 1:1 is of great significance to the marketization and long-distance transportation scenarios such as foreign trade of two-component silicone sealants with a volume ratio of 2:1 and 1:1. Summary of the invention

[0006] The invention provides a two-component silicone sealant with a long storage period and a preparation method thereof, and aims to solve the storage period problem of the existing two-component silicone sealant with a volume ratio of 2:1 and 1:1.

[0007] In order to achieve the above-mentioned purpose, the embodiment of the present invention provides a two-component silicone sealant with a long shelf life and a preparation method thereof. The method first prepares a two-component component A with α, ω-dihydroxy polydimethylsiloxane, dimethyl silicone oil and filler. The alkoxy-terminated 107 glue, filler and dehydrating material are subjected to physical and chemical double dehydration, and then pretreated with ketoxime siloxane to obtain a modified base material; the crosslinking agent, coupling agent and catalyst are pretreated to obtain a mixed vulcanizing agent; and the two-component component B is prepared with the improved base material, hydrophobic white carbon black and mixed vulcanizing agent. The A component and the B component are combined to prepare a two-component silicone sealant with a volume ratio of 1 to 2:1 and a shelf life of 12 months.

[0008] An embodiment of the present invention provides a two-component silicone sealant with a long shelf life, comprising a component A and a component B, wherein the volume ratio of the component A to the component B is 1:1 to 2:1;

[0009] In parts by weight, the component A comprises the following components:

[0010]

[0011] In parts by weight, the B component includes the following components:

[0012]

[0013] Preferably, the viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25° C. is 1000 to 10000 cps.

[0014] Preferably, the viscosity of the dimethyl silicone oil at 25° C. is 100 to 1000 cps.

[0015] Preferably, the particle size of the active nano-calcium carbonate is 1 to 15 μm; the particle size of the heavy calcium carbonate is 70 to 250 μm.

[0016] Preferably, the polyalkoxy-terminated polydimethoxysilane has a viscosity of 1500 to 20000 cps at 25°C.

[0017] Preferably, the water-removing filler is a mixture of calcium oxide and molecular sieve activation powder, and the particle size of the water-removing filler is 10 to 100 μm; wherein the mixing ratio of calcium oxide to molecular sieve activation powder is 1:1 to 1:2.

[0018] Preferably, the specific surface area of ​​the hydrophobic white carbon black is 150 to 200 m 2 / g.

[0019] Preferably, the crosslinking agent 1 is at least one of methyltributylacetoximate silane, vinyltributylacetoximate silane, phenyltributylacetoximate silane, and tetrabutylketoxime silane; the crosslinking agent 2 is at least two of ethyl orthosilicate, propyl orthosilicate, butyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

[0020] Preferably, the coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; and the catalyst is at least one of dibutyltin diacetate, dibutyltin dilaurate, dibutyltin diacetylacetonate, and dioctyltin dilaurate.

[0021] Based on a general concept of the invention, an embodiment of the present invention provides a method for preparing the above-mentioned two-component silicone sealant with a long shelf life, comprising the following steps:

[0022] S1: α, ω-dihydroxy polydimethylsiloxane, dimethyl silicone oil, active nano calcium carbonate, and heavy calcium carbonate are sequentially put into a planetary machine, and stirred for 60 to 90 minutes under a vacuum degree of -0.09 MPa to -0.1 MPa to prepare component A;

[0023] S2: specifically includes the following steps:

[0024] S2.1 Put polyalkoxy-terminated polydimethylsiloxane, active nano calcium carbonate and heavy calcium carbonate into a kneader in sequence, knead for 2 hours at a temperature of 105 to 130° C. and a vacuum degree of -0.09 MPa to -0.1 MPa, then put in a dewatering filler, and continue kneading for 1 hour at a temperature of 105 to 120° C. and a vacuum degree of -0.09 MPa to -0.1 MPa to obtain a base material;

[0025] S2.2 The base material is cooled to 50-65°C under a vacuum degree of -0.09 MPa to -0.1 MPa, a crosslinking agent 1 is added, and the mixture is kneaded at a temperature of 50-65°C and a vacuum degree of -0.09 MPa to -0.1 MPa for 1 hour to obtain a modified base material;

[0026] S2.3 Add crosslinking agent 2, coupling agent and one quarter of catalyst into the reaction kettle in sequence, stir thoroughly for 1 hour at a temperature of 40-60°C and a vacuum degree of -0.09 MPa to -0.1 MPa, and after cooling to room temperature, add the remaining three quarters of the catalyst, stir thoroughly for 0.5 hour at a vacuum degree of -0.09 MPa to -0.1 MPa to obtain a mixed vulcanizing agent;

[0027] S2.4 Heat the hydrophobic silica in an oven at 105°C for 24 hours and set aside;

[0028] S2.5 The modified base material, the hydrophobic silica after the heat treatment, and the mixed vulcanizing agent are sequentially put into a planetary machine, and stirred for 60 to 90 minutes under a vacuum degree of -0.09 MPa to -0.1 MPa to prepare component B;

[0029] S3: The component A and the component B are mixed evenly in a volume ratio of 1:1 to 2:1, degassed, and cured at room temperature to prepare a two-component silicone sealant.

[0030] Reaction mechanism

[0031] The present invention first physically dehydrates the base material, and then chemically dehydrates the base material with calcium oxide and molecular sieve powder, deeply removes the free water and crystal water of the filler, and does not produce excessive calcium hydroxide to cause the silicone sealing tape to be strongly alkaline, and then selects a small amount of highly active ketoxime-based crosslinking agent to pretreat the base material to obtain a modified base material. Water is one of the reaction raw materials for the hydrolysis of siloxane, and the modified base material greatly inhibits the hydrolysis of the siloxane crosslinking agent, and the modification of siloxane further eliminates the remaining Si-OH group of the polyalkoxy-terminated polydimethoxysilane. Under the combination of the two, the thickening phenomenon caused by slow crosslinking during storage is well alleviated. In addition, the present invention also pre-treats the siloxane crosslinking agent, the coupling agent and part of the catalyst by heating, releasing a part of the side reaction in advance, and then replenishing the remaining catalyst. This will not lead to a decrease in the overall reaction activity, and can reduce the catalyst deactivation caused by the side reaction of the auxiliary agent during the storage of the silicone sealant.

[0032] The above scheme of the present invention has the following beneficial effects:

[0033] The present invention first prepares a two-component component A with α, ω-dihydroxy polydimethylsiloxane, dimethyl silicone oil and filler. The alkoxy-terminated 107 glue, filler and dehydrating material are subjected to physical and chemical double dehydration, and then pretreated with ketoxime-based siloxane to obtain a modified base material; the crosslinking agent, coupling agent and catalyst are pretreated to obtain a mixed vulcanizing agent; and the two-component component B is prepared with the improved base material, hydrophobic white carbon black and mixed vulcanizing agent. Component A and component B are mixed in a volume ratio of 1:1 to 2:1 to prepare a two-component silicone sealant. The two-component silicone sealant of the present invention can have no obvious thickening during the long-term storage process of 12 months, and maintain a stable tearing time and vulcanization effect within the validity period of 12 months, which is of great significance for scenarios such as foreign trade and ocean transportation that require a long storage period. DETAILED DESCRIPTION

[0034] In order to make the technical problems to be solved, technical solutions and advantages of the present invention more clear, they are described in detail below in conjunction with specific embodiments.

[0035] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0036] 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.

[0037] In view of the existing problems, the present invention provides a two-component silicone sealant with a long storage period and a preparation method thereof.

[0038] The following is a detailed description through specific embodiments.

[0039] Example 1

[0040] This embodiment provides a method for preparing a two-component silicone sealant with a long shelf life.

[0041] The method of this embodiment specifically includes the following steps:

[0042] Step 1, prepare component A: put 100 parts of 10000cps α, ω-dihydroxypolydimethylsiloxane, 20 parts of 350cps dimethyl silicone oil, 100 parts of active nano-calcium carbonate, and 20 parts of heavy calcium carbonate into a planetary machine in sequence, and stir for 90 minutes under a vacuum degree of -0.09MPa to -0.1MPa to obtain component A.

[0043] Step 2: Preparation of component B:

[0044] ① 100 parts of 20000cps polyalkoxy-terminated polydimethylsiloxane, 80 parts of active nano-calcium carbonate, and 20 parts of heavy calcium carbonate are sequentially put into a kneader, kneaded for 2 hours at a temperature of 105-130°C and a vacuum degree of -0.09MPa to -0.1MPa, and then 2.5 parts of calcium oxide and 2.5 parts of molecular sieves are added, and kneaded for 1 hour at a temperature of 105-120°C and a vacuum degree of -0.09MPa to -0.1MPa to obtain a base material; the above base material is cooled to 60°C at a vacuum degree of -0.09MPa to -0.1MPa, and 8 parts of methyltributylidene oxime silane are continuously added, and kneaded for 1 hour at a temperature of 50°C to 65°C and a vacuum degree of -0.09MPa to -0.1MPa to obtain a modified base material. ② Add 15 parts of methyltrimethoxysilane, 5 parts of ethyl orthosilicate, 8 parts of γ-aminopropyltriethoxysilane, and 0.25 parts of dibutyltin dilaurate into the reaction kettle in sequence, and stir them thoroughly for 1 hour at a temperature of 40℃~60℃ and a vacuum degree of -0.09MPa to -0.1MPa. After cooling to room temperature, add 0.75 parts of dibutyltin dilaurate, and stir them thoroughly for 0.5 hours at a vacuum degree of -0.09MPa to -0.1MPa to obtain a mixed vulcanizing agent. ③ Add a 150m 2 / g of hydrophobic white carbon black is heated in an oven at 105°C for 24 hours and set aside. ④ 200 parts of the modified base material, 5 parts of the hydrophobic white carbon black and 25 parts of the mixed vulcanizing agent are sequentially put into a planetary machine and stirred for 60 minutes under a vacuum degree of -0.09MPa to -0.1MPa to obtain component B.

[0045] Step 3, preparation of sealant: when using, the above-mentioned component A and component B are mixed evenly in a volume ratio of 1:1 and degassed, and then cured in an environment with a temperature of 23° C. and a humidity of 50%.

[0046] Example 2

[0047] This embodiment provides a method for preparing a two-component silicone sealant with a long shelf life.

[0048] The method of this embodiment specifically includes the following steps:

[0049] Step 1, prepare component A: put 100 parts of 10000cps α, ω-dihydroxypolydimethylsiloxane, 20 parts of 350cps dimethyl silicone oil, 100 parts of active nano-calcium carbonate, and 20 parts of heavy calcium carbonate into a planetary machine in sequence, and stir for 90 minutes under a vacuum degree of -0.09MPa to -0.1MPa to obtain component A.

[0050] Step 2: Preparation of component B:

[0051] ① 100 parts of 1500cps polyalkoxy-terminated polydimethylsiloxane, 90 parts of active nano-calcium carbonate, and 10 parts of heavy calcium carbonate are sequentially put into a kneader, kneaded for 2 hours at a temperature of 105-130°C and a vacuum degree of -0.09MPa to -0.1MPa, and then 2.5 parts of calcium oxide and 2.5 parts of molecular sieves are added, and kneaded for 1 hour at a temperature of 105-120°C and a vacuum degree of -0.09MPa to -0.1MPa to obtain a base material; the above base material is cooled to 60°C at a vacuum degree of -0.09MPa to -0.1MPa, and 8 parts of tetrabutyl ketoxime silane are continuously added, and kneaded for 1 hour at a temperature of 50°C to 65°C and a vacuum degree of -0.09MPa to -0.1MPa to obtain a modified base material. ② Add 15 parts of methyltrimethoxysilane, 5 parts of methyl orthosilicate, 8 parts of γ-aminopropyltriethoxysilane, and 0.25 parts of dibutyltin dilaurate into the reaction kettle in sequence, and stir them thoroughly for 1 hour at a temperature of 40℃~60℃ and a vacuum degree of -0.09MPa to -0.1MPa. After cooling to room temperature, add 0.75 parts of dibutyltin dilaurate, and stir them thoroughly for 0.5 hours at a vacuum degree of -0.09MPa to -0.1MPa to obtain a mixed vulcanizing agent. ③ Add a 150m 2 / g of hydrophobic white carbon black was heated in an oven at 105°C for 24 hours and set aside. ④ 200 parts of the modified base material, 8 parts of the hydrophobic white carbon black and 40 parts of the mixed vulcanizing agent were sequentially put into a planetary machine and stirred for 60 minutes under a vacuum degree of -0.09MPa to -0.1MPa to obtain component B.

[0052] Step 3, preparation of sealant: when using, the above-mentioned component A and component B are mixed evenly in a volume ratio of 2:1 and degassed, and then cured in an environment with a temperature of 23° C. and a humidity of 50%.

[0053] Example 3

[0054] This embodiment provides a method for preparing a two-component silicone sealant with a long shelf life.

[0055] The method of this embodiment specifically includes the following steps:

[0056] Step 1, prepare component A: put 100 parts of 10000cps α, ω-dihydroxypolydimethylsiloxane, 20 parts of 350cps dimethyl silicone oil, 100 parts of active nano-calcium carbonate, and 20 parts of heavy calcium carbonate into a planetary machine in sequence, and stir for 90 minutes under a vacuum degree of -0.09MPa to -0.1MPa to obtain component A.

[0057] Step 2: Preparation of component B:

[0058] ① 100 parts of 1500cps polyalkoxy-terminated polydimethylsiloxane, 80 parts of active nano-calcium carbonate, and 20 parts of heavy calcium carbonate are sequentially put into a kneader, kneaded for 2 hours at a temperature of 105-130°C and a vacuum degree of -0.09MPa to -0.1MPa, and then 2.5 parts of calcium oxide and 2.5 parts of molecular sieves are added, and kneaded for 1 hour at a temperature of 105-120°C and a vacuum degree of -0.09MPa to -0.1MPa to obtain a base material; the above base material is cooled to 60°C at a vacuum degree of -0.09MPa to -0.1MPa, and 8 parts of vinyl trisbutyl ketoxime silane are continuously added, and kneaded for 1 hour at a temperature of 50°C to 65°C and a vacuum degree of -0.09MPa to -0.1MPa to obtain a modified base material. ② Add 15 parts of methyltriethoxysilane, 5 parts of ethyl orthosilicate, 8 parts of γ-aminopropyltriethoxysilane, and 0.25 parts of dibutyltin dilaurate into the reaction kettle in sequence, and stir them thoroughly for 1 hour at a temperature of 40℃~60℃ and a vacuum degree of -0.09MPa to -0.1MPa. After cooling to room temperature, add 0.75 parts of dibutyltin dilaurate, and stir them thoroughly for 0.5 hours at a vacuum degree of -0.09MPa to -0.1MPa to obtain a mixed vulcanizing agent. ③ Add a 150m 2 / g of hydrophobic white carbon black is heated in an oven at 105°C for 24 hours and set aside. ④ 200 parts of the modified base material, 8 parts of the hydrophobic white carbon black and 30 parts of the mixed vulcanizing agent are sequentially put into a planetary machine and stirred for 60 minutes under a vacuum degree of -0.09MPa to -0.1MPa to obtain component B.

[0059] Step 3, preparation of sealant: when using, the above-mentioned component A and component B are mixed evenly in a volume ratio of 1:1 and degassed, and then cured in an environment with a temperature of 23° C. and a humidity of 50%.

[0060] Comparative Example 1

[0061] The only difference from Example 1 is that no water-removing filler is added, and the remaining components, preparation process and parameters are the same as those of Example 1.

[0062] Comparative Example 2

[0063] The only difference from Example 1 is that the crosslinking agent 1 is not added, and the other components, preparation process and parameters are the same as those of Example 1.

[0064] Comparative Example 3

[0065] A method for preparing a two-component silicone sealant specifically comprises the following steps:

[0066] Step 1, prepare component A: put 100 parts of 10000cps α, ω-dihydroxypolydimethylsiloxane, 20 parts of 350cps dimethyl silicone oil, 100 parts of active nano-calcium carbonate, and 20 parts of heavy calcium carbonate into a planetary machine in sequence, and stir for 90 minutes under a vacuum degree of -0.09MPa to -0.1MPa to obtain component A.

[0067] Step 2, preparation of component B: ① Put 100 parts of 20000cps polyalkoxy-terminated polydimethylsiloxane, 80 parts of active nano calcium carbonate, and 20 parts of heavy calcium carbonate into a kneader in sequence, knead for 2 hours at a temperature of 105-130°C and a vacuum degree of -0.09MPa to -0.1MPa, then add 2.5 parts of calcium oxide and 2.5 parts of molecular sieves, and continue kneading for 1 hour at a temperature of 105-120°C and a vacuum degree of -0.09MPa to -0.1MPa to obtain the base material; cool the above base material to 60°C at a vacuum degree of -0.09MPa to -0.1MPa, continue to add 8 parts of methyl tributylidene oxime silane, and knead for 1 hour at a temperature of 50°C to 65°C and a vacuum degree of -0.09MPa to -0.1MPa to obtain the modified base material. ② Put a 150m 2 / g of hydrophobic silica was heated in an oven at 105°C for 24h and set aside. ③ 200 parts of the modified base material, 5 parts of the hydrophobic silica, 15 parts of methyltrimethoxysilane, 5 parts of ethyl orthosilicate, 8 parts of γ-aminopropyltriethoxysilane and 1 part of dibutyltin dilaurate were sequentially put into a planetary machine and stirred for 60min under a vacuum degree of -0.09MPa to -0.1MPa to obtain component B.

[0068] Step 3, preparation of sealant: When using, the above-mentioned component A and component B are mixed evenly in a volume ratio of 1:1 and degassed, and cured in an environment with a temperature of 23° C. and a humidity of 50%.

[0069] Comparative Example 4

[0070] A method for preparing a two-component silicone sealant specifically comprises the following steps:

[0071] Step 1, prepare component A: put 100 parts of 10000cps α, ω-dihydroxypolydimethylsiloxane, 20 parts of 350cps dimethyl silicone oil, 100 parts of active nano-calcium carbonate, and 20 parts of heavy calcium carbonate into a planetary machine in sequence, and stir for 90 minutes under a vacuum degree of -0.09MPa to -0.1MPa to obtain component A.

[0072] Step 2: Preparation of component B:

[0073] ① Put 100 parts of 20000cps polyalkoxy-terminated polydimethylsiloxane, 80 parts of active nano-calcium carbonate, 20 parts of heavy calcium carbonate, 2.5 parts of calcium oxide and 2.5 parts of molecular sieve into a kneader in sequence, and knead for 2 hours at a temperature of 105-120°C and a vacuum degree of -0.09MPa to -0.1MPa to obtain a base material; cool the above base material to 60°C at a vacuum degree of -0.09MPa to -0.1MPa, continue to add 8 parts of methyl tributylidene oxime silane, and knead for 1 hour at a temperature of 50°C to 65°C and a vacuum degree of -0.09MPa to -0.1MPa to obtain a modified base material. ② Add 15 parts of methyltrimethoxysilane, 5 parts of ethyl orthosilicate, 8 parts of γ-aminopropyltriethoxysilane, and 0.25 parts of dibutyltin dilaurate into the reaction kettle in sequence, and stir them thoroughly for 1 hour at a temperature of 40℃~60℃ and a vacuum degree of -0.09MPa to -0.1MPa. After cooling to room temperature, add 0.75 parts of dibutyltin dilaurate, and stir them thoroughly for 0.5 hours at a vacuum degree of -0.09MPa to -0.1MPa to obtain a mixed vulcanizing agent. ③ Add a 150m 2 / g of hydrophobic white carbon black is heated in an oven at 105°C for 24 hours and set aside. ④ 200 parts of the modified base material, 5 parts of the hydrophobic white carbon black and 25 parts of the mixed vulcanizing agent are sequentially put into a planetary machine and stirred for 60 minutes under a vacuum degree of -0.09MPa to -0.1MPa to obtain component B.

[0074] Step 3, preparation of sealant: When using, the above-mentioned component A and component B are mixed evenly in a volume ratio of 1:1 and degassed, and cured in an environment with a temperature of 23° C. and a humidity of 50%.

[0075] Comparative Example 5

[0076] The only difference from Example 2 is that when preparing component B, a specific surface area of ​​150 m 2 / g of hydrophilic silica was heated in an oven at 105°C for 24h, and the remaining components, preparation process and parameters were the same as those in Example 2.

[0077] Comparative Example 6

[0078] The only difference from Example 3 is that calcium oxide is used as the water-removing filler when preparing component B. The remaining components, preparation process and parameters are the same as those in Example 3.

[0079] Comparative Example 7

[0080] The only difference from Example 3 is that when preparing component B, all water-removing fillers are molecular sieves. The remaining components, preparation process and parameters are the same as those in Example 3.

[0081] The two-component silicone sealants prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were subjected to the following performance tests.

[0082] The tensile strength test refers to the standard GB / T 528-2009; the breaking time test refers to the standard GB 16776-2005 Appendix D.5; the surface drying time test refers to the standard GB / T 13477.5-2002; the consistency test refers to the standard GB / T 1749-1979.

[0083] Table 1 Performance test results of two-component silicone sealants of Examples 1 to 4

[0084]

[0085] Table 2 Performance test results of two-component silicone sealants of comparative examples 1 to 7

[0086]

[0087]

[0088] Note: "Gel" refers to the state in which the silicone sealant is partially cross-linked in the bottle to form an elastic body and cannot be squeezed out.

[0089] From the comparison of the results of the embodiments and the comparative examples, it can be seen that the physical and chemical dehydration methods of the present invention for treating the base material can effectively reduce the water content of the base material, the selected hydrophobic silica can achieve reinforcement without significantly affecting the storage period, and the pretreated cross-linking agent, coupling agent and catalyst also have excellent stability, so that the prepared component B can have a storage period of more than 12 months, component B does not thicken during storage, and the mechanical strength is maintained without decreasing.

[0090] Compared with Example 1, Comparative Example 1 did not add dehydrating filler, and the obtained two-component silicone sealant had thickened significantly at 6 months and the gel could not be used after 12 months; Comparative Example 2 did not add crosslinking agent 1 for pre-crosslinking compared with Example 1, and the obtained two-component silicone sealant thickened at 6 months and thickened significantly after 12 months. Compared with Example 1, Comparative Example 3 did not pretreat the crosslinking agent, coupling agent and catalyst, and the curing rate of the obtained two-component silicone sealant began to slow down at 6 months, and the curing rate decreased significantly after 12 months, and the strength was significantly reduced due to incomplete crosslinking. Compared with Example 1, Comparative Example 4 did not use physical dehydration to treat the base material, but directly used chemical dehydration to treat the base material. The obtained two-component silicone sealant thickened significantly at 6 months and the gel could not be used after 12 months. Comparative Example 5 is compared with Example 2, and hydrophilic white carbon black is used as a reinforcing filler. The silicone sealant obtained thickened significantly during the 12-month storage process, and the curing rate was significantly reduced. This shows that the moisture in component B has a fatal impact on the storage period, and the combination of physical and chemical dehydration can effectively remove the crystal water in the filler; the pre-blocking of the ketoxime crosslinker can also effectively remove the incompletely blocked Si-OH groups of the blocked 107 glue, reducing its reaction activity during subsequent storage. The pretreatment of the crosslinker, coupling agent and catalyst has carried out side reactions in advance, and the intermediates formed will no longer continue to affect the catalytic activity, which makes the prepared two-component silicone sealant have an ultra-long storage period of 12 months, does not thicken during storage, and maintains excellent curing rate and mechanical properties.

[0091] Comparative Examples 6 and 7 are compared with Example 3. Comparative Example 6 uses calcium oxide as a dewatering filler, and Comparative Example 7 uses molecular sieves as a dewatering filler. Although the two-component silicone sealant obtained in Comparative Example 6 does not thicken and maintains a better curing rate, its strength is significantly reduced. The two-component silicone sealant obtained in Comparative Example 7 is well stored, but gels in December. This shows that under the synergistic effect of calcium oxide and molecular sieves, the amount of calcium oxide can be effectively reduced, the alkalinity of the silicone sealant can be reduced, and the prepared two-component silicone sealant maintains excellent mechanical properties during storage.

[0092] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A two-component silicone sealant with a long shelf life, characterized in that: The invention comprises a component A and a component B, wherein the volume ratio of the component A to the component B is 1:1 to 2:1; In parts by weight, the component A comprises the following components: In parts by weight, the B component includes the following components:

2. The two-component silicone sealant with a long shelf life according to claim 1, characterized in that: The viscosity of the α,ω-dihydroxy polydimethylsiloxane at 25° C. is 1000 to 10000 cps.

3. The two-component silicone sealant with a long shelf life according to claim 1, characterized in that: The viscosity of the dimethyl silicone oil at 25° C. is 100 to 1000 cps.

4. The two-component silicone sealant with a long shelf life according to claim 1, characterized in that: The particle size of the active nano calcium carbonate is 1 to 15 μm; the particle size of the heavy calcium carbonate is 70 to 250 μm.

5. The two-component silicone sealant with a long shelf life according to claim 1, characterized in that: The viscosity of the polyalkoxy-terminated polydimethoxysilane at 25° C. is 1500 to 20000 cps.

6. The two-component silicone sealant with a long shelf life according to claim 1, characterized in that: The dewatering filler is a mixture of calcium oxide and molecular sieve activation powder, and the particle size of the dewatering filler is 10-100 μm; wherein the mixing ratio of calcium oxide to molecular sieve activation powder is 1:1 to 1:

2.

7. The two-component silicone sealant with a long shelf life according to claim 1, characterized in that: The specific surface area of ​​the hydrophobic white carbon black is 150 to 200 m 2 / g.

8. The two-component silicone sealant with a long shelf life according to claim 1, characterized in that: The crosslinking agent 1 is at least one of methyltributylacetoximate silane, vinyltributylacetoximate silane, phenyltributylacetoximate silane, and tetrabutylketoxime silane; the crosslinking agent 2 is at least two of ethyl orthosilicate, propyl orthosilicate, butyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

9. The two-component silicone sealant with a long shelf life according to claim 1, characterized in that: The coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; the catalyst is at least one of dibutyltin diacetate, dibutyltin dilaurate, dibutyltin diacetylacetonate, and dioctyltin dilaurate.

10. The method for preparing a two-component silicone sealant with a long shelf life according to any one of claims 1 to 9, characterized in that: The steps include: S1: α, ω-dihydroxy polydimethylsiloxane, dimethyl silicone oil, active nano calcium carbonate, and heavy calcium carbonate are sequentially put into a planetary machine, and stirred for 60 to 90 minutes under a vacuum degree of -0.09 MPa to -0.1 MPa to prepare component A; S2: specifically includes the following steps: S2.1 Put polyalkoxy-terminated polydimethylsiloxane, active nano calcium carbonate and heavy calcium carbonate into a kneader in sequence, knead for 2 hours at a temperature of 105 to 130° C. and a vacuum degree of -0.09 MPa to -0.1 MPa, then put in a dewatering filler, and continue kneading for 1 hour at a temperature of 105 to 120° C. and a vacuum degree of -0.09 MPa to -0.1 MPa to obtain a base material; S2.2 The base material is cooled to 50-65°C under a vacuum degree of -0.09 MPa to -0.1 MPa, a crosslinking agent 1 is added, and the mixture is kneaded at a temperature of 50-65°C and a vacuum degree of -0.09 MPa to -0.1 MPa for 1 hour to obtain a modified base material; S2.3 Add crosslinking agent 2, coupling agent and one quarter of catalyst into the reaction kettle in sequence, stir thoroughly for 1 hour at a temperature of 40-60°C and a vacuum degree of -0.09 MPa to -0.1 MPa, and after cooling to room temperature, add the remaining three quarters of the catalyst, stir thoroughly for 0.5 hour at a vacuum degree of -0.09 MPa to -0.1 MPa to obtain a mixed vulcanizing agent; S2.4 Heat the hydrophobic silica in an oven at 105°C for 24 hours and set aside; S2.5 The modified base material, the hydrophobic silica after the heat treatment, and the mixed vulcanizing agent are sequentially put into a planetary machine, and stirred for 60 to 90 minutes under a vacuum degree of -0.09 MPa to -0.1 MPa to prepare component B; S3: The component A and the component B are mixed evenly in a volume ratio of 1:1 to 2:1, degassed, and cured at room temperature to prepare a two-component silicone sealant.

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