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

Abstract

The application provides a long-storage-period two-component silicone sealant and a preparation method thereof, and relates to the field of silicone sealant materials. The method comprises the following steps: preparing component A by using alpha, omega-dihydroxypolydimethylsiloxane, dimethyl silicone oil and fillers; preparing a modified base by using alkoxy-terminated 107 glue, fillers and water-removing materials to perform physical and chemical double dehydration, and then using ketoxime silicone for pretreatment; preparing a mixed vulcanizing agent by pretreating a crosslinking agent, a coupling agent and a catalyst; preparing component B by using the modified base, hydrophobic white carbon black and the mixed vulcanizing agent; and mixing component A and component B in a volume ratio of 1-2:1 to prepare the two-component silicone sealant. The two-component silicone sealant has no obvious thickening in a long storage period of 12 months, and can maintain stable breaking time and vulcanization effect in a validity period of 12 months, which has very important significance for long-storage-period scenes such as foreign trade and ocean transportation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of silicone sealant materials, in particular to a long-storage two-component silicone sealant and a preparation method thereof. BACKGROUND

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

[0003] The two-component silicone sealant is widely used in continuous operation, short turnaround time bonding scenes such as hollow glass, photovoltaic frame, kitchen utensils and cooking table, due to its excellent rapid curing mechanism.

[0004] In actual application, different proportions of two-component silicone sealant have their own advantages. The two-component silicone sealant with volume ratio of 10:1 and 6:1 has the advantages of long storage time, high strength and better weather resistance, but also has the disadvantages of large mixing ratio difference, high requirement for equipment precision, high equipment price and poor anti-volatility ability to mixing ratio. The two-component silicone sealant with volume ratio of 2:1 and 1:1 has the advantages of low requirement for equipment and 10% to 20% of mixing fluctuation, but in order to ensure strength and construction, the content of additives in component B is lower and the content of filler is higher. The moisture in the filler will cause the 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 the two-component with volume ratio of 2:1 and 1:1 has important significance for popularizing the marketization of two-component silicone sealant with volume ratio of 2:1 and 1:1 and long transportation scenes such as foreign trade. SUMMARY

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

[0007] To achieve the above object, the embodiment of the present application provides a long-storage dual-component silicone sealant and a preparation method thereof. The method comprises the following steps: preparing a dual-component A component by using α, ω-dihydroxyl polydimethylsiloxane, dimethyl silicone oil and filler; preparing a modified base by using alkoxy-terminated 107 glue, filler and water-removing material through physical and chemical double dehydration, and then pretreating the modified base by using ketoxime silicone; preparing a mixed vulcanizing agent by pretreating a crosslinking agent, a coupling agent and a catalyst; and preparing a dual-component B component by using the modified base, hydrophobic white carbon black and the mixed vulcanizing agent. The A component and the B component are combined to prepare the dual-component silicone sealant with a storage period of 12 months and a volume ratio of 1-2:1.

[0008] The embodiment of the present application provides a long-storage dual-component silicone sealant, which comprises an A component and a B component, and the volume ratio of the A component to the B component is 1:1 to 2:1.

[0009] The A component comprises the following components in parts by weight:

[0010]

[0011] The B component comprises the following components in parts by weight:

[0012]

[0013] Preferably, the α, ω-dihydroxyl polydimethylsiloxane has a viscosity of 1000-10000 cps at 25 DEG C.

[0014] Preferably, the dimethyl silicone oil has a viscosity of 100-1000 cps at 25 DEG C.

[0015] Preferably, the active nano calcium carbonate has a particle size of 1-15 microns, and the heavy calcium carbonate has a particle size of 70-250 microns.

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

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

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

[0019] Preferably, the cross-linking agent 1 is at least one of methyltris(butanone oxime)silane, vinyltris(butanone oxime)silane, phenyltris(butanone oxime)silane, tetrakis(butanone oxime)silane; the cross-linking agent 2 is at least two of ethyl silicate, propyl silicate, butyl silicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane.

[0020] Preferably, the coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane; the catalyst is at least one of dibutyl tin diacetate, dibutyl tin dilaurate, dibutyl tin diacetylacetone, dioctyl tin dilaurate.

[0021] Based on the general concept of one invention, embodiments of the present application provide a preparation method of the above-mentioned long-storage dual-component silicone sealant, comprising the following steps:

[0022] S1: sequentially adding α, ω-dihydroxypolydimethylsiloxane, dimethyl silicone oil, active nano calcium carbonate, heavy calcium carbonate into a planetary machine, stirring for 60-90 min under the condition of a vacuum degree of-0.09 MPa to-0.1 MPa, to obtain component A;

[0023] S2: specifically comprising the following steps:

[0024] S2.1: sequentially adding polyalkoxy-terminated polydimethylsiloxane, active nano calcium carbonate, heavy calcium carbonate into a kneader, kneading for 2 h under the condition of a temperature of 105-130 ℃ and a vacuum degree of-0.09 MPa to-0.1 MPa, then adding water-removing filler, continuing to knead for 1 h under the condition of a temperature of 105-120 ℃ and a vacuum degree of-0.09 MPa to-0.1 MPa, to obtain a base material;

[0025] S2.2: cooling the base material to 50-65 ℃ under a vacuum degree of-0.09 MPa to-0.1 MPa, adding cross-linking agent 1, kneading for 1 h under the condition of a temperature of 50-65 ℃ and a vacuum degree of-0.09 MPa to-0.1 MPa, to obtain a modified base material;

[0026] S2.3: sequentially adding cross-linking agent 2, coupling agent, one fourth of the catalyst into a reaction kettle, fully stirring for 1 h under the condition of a temperature of 40-60 ℃ and a vacuum degree of-0.09 MPa to-0.1 MPa, after cooling to room temperature, adding the remaining three fourths of the catalyst, fully stirring for 0.5 h under a vacuum degree of-0.09 MPa to-0.1 MPa, to obtain a mixed vulcanizing agent;

[0027] S2.4: heating and treating the hydrophobic white carbon black in a 105 ℃ oven for 24 h for standby use;

[0028] S2.5 The modified base material, hydrophobic white carbon black after heat treatment, mixed vulcanizing agent is put into the planetary machine in turn, and stirring is carried out for 60-90 min under the condition of vacuum degree of-0.09 MPa to-0.1 MPa to prepare the B component;

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

[0030] Reaction mechanism

[0031] The application first carries out physical dehydration on the base material, and then carries out chemical dehydration on the base material by using calcium oxide and molecular sieve powder, thereby deeply removing the free water and crystal water of the filler without causing excessive calcium hydroxide to cause strong alkalinity of the silicone sealant, and then a small amount of high-activity ketoxime-based crosslinking agent is selected to pretreat the base material to obtain a modified base material. Water is one of the reaction raw materials of siloxane hydrolysis, and the modified base material greatly inhibits the hydrolysis of the siloxane crosslinking agent, and the modification of the siloxane further eliminates the residual Si-OH groups of the polydimethylsiloxane terminated with multiple alkyl groups. Under the combination of the two, the thickening phenomenon caused by slow crosslinking during storage is well relieved. In addition, the application also carries out heat pretreatment on the siloxane crosslinking agent, the coupling agent and part of the catalyst, releases a part of the by-products in advance, and then supplements the remaining catalyst. This can not only reduce the deactivation of the catalyst caused by the by-reaction of the additives during the storage of the silicone sealant, but also can reduce the deactivation of the catalyst caused by the by-reaction of the additives during the storage of the silicone sealant.

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

[0033] The application first prepares the A component of two components by using alpha, omega-dihydroxy polydimethylsiloxane, dimethyl silicone oil and filler. The modified base material is obtained by double dehydration of the alkyl-terminated 107 glue, filler and water removal material, and then pretreated by ketoxime-based siloxane. The mixed vulcanizing agent is obtained by pretreating the crosslinking agent, the coupling agent and the catalyst. The B component of two components is prepared by using the improved base material, the hydrophobic white carbon black and the mixed vulcanizing agent. The A component and the B component are mixed according to the volume ratio of 1:1 to 2:1 to prepare the two-component silicone sealant. The two-component silicone sealant of the application can not be obviously thickened during the long-term storage of 12 months, and can maintain stable breaking time and vulcanization effect within the effective period of 12 months. It has very important significance for the scene with long storage period demand such as foreign trade and ocean transportation. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical schemes and advantages of the application more clear, specific embodiments will be described in detail below.

[0035] Unless otherwise defined, all terms used in the disclosure, including technical terms and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. The terms used in the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the scope of the present disclosure.

[0036] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present disclosure can be purchased from the market or prepared by existing methods.

[0037] The present disclosure provides a two-component silicone sealant with a long storage period and a preparation method thereof.

[0038] The following will be described through specific examples.

[0039] Example 1

[0040] The present embodiment relates to a preparation method of a two-component silicone sealant with a long storage period.

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

[0042] Step one, preparation of component A: 100 parts of 10000 cps α, ω-dihydroxy polydimethylsiloxane, 20 parts of 350 cps dimethyl silicone oil, 100 parts of active nano calcium carbonate, and 20 parts of heavy calcium carbonate are sequentially put into a planetary machine, and stirred for 90 min under the condition of a vacuum degree of-0.09 MPa to-0.1 MPa, to obtain component A.

[0043] Step two, preparation of component B:

[0044] Step 1: Preparation of A component: 100 parts of 10000 cps α, ω-dihydroxypolydimethylsiloxane, 20 parts of 350 cps dimethyl silicone oil, 100 parts of active nano calcium carbonate, and 20 parts of heavy calcium carbonate were sequentially put into a planetary mixer and stirred for 90 min under the condition of a vacuum degree of -0.09 MPa to -0.1 MPa, to obtain the A component. 2 Step 3: Preparation of the sealant: when used, the A component and the B component were mixed uniformly 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%, to obtain the sealant.

[0045] Step 3: Preparation of the sealant: when used, the A component and the B component were mixed uniformly 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%, to obtain the sealant.

[0046] Example 2

[0047] The present embodiment protects a method for preparing a two-component silicone sealant with a long storage period.

[0048] The method of the present embodiment specifically comprises the following steps:

[0049] Step 1: Preparation of A component: 100 parts of 10000 cps α, ω-dihydroxypolydimethylsiloxane, 20 parts of 350 cps dimethyl silicone oil, 100 parts of active nano calcium carbonate, and 20 parts of heavy calcium carbonate were sequentially put into a planetary mixer and stirred for 90 min under the condition of a vacuum degree of -0.09 MPa to -0.1 MPa, to obtain the A component.

[0050] Step 2: Preparation of B component:

[0051] Step 1, preparation of A component: 100 parts of 1500 cps polydimethylsiloxane terminated by multi-alkoxy, 90 parts of active nano calcium carbonate, 10 parts of heavy calcium carbonate were put into a kneader in turn, and kneaded for 2 hours under the temperature of 105-130℃ and the vacuum degree of -0.09MPa to -0.1MPa, then 2.5 parts of calcium oxide and 2.5 parts of molecular sieve were put into the kneader, and the kneading was continued for 1 hour under the temperature of 105-120℃ and the vacuum degree of -0.09MPa to -0.1MPa, thus the base material was obtained; the base material was cooled to 60℃ under the vacuum degree of -0.09MPa to -0.1MPa, and 8 parts of tetrabutyl ketoxime silane was continuously added, and kneaded for 1 hour under the temperature of 50-65℃ and the vacuum degree of -0.09MPa to -0.1MPa, thus the modified base material was obtained. 2 Step 3, preparation of the sealant: when used, the A component and the B component were mixed uniformly according to the volume ratio of 2:1 and defoamed, and cured in the environment with the temperature of 23℃ and the humidity of 50%, thus the sealant was obtained.

[0052] Step 3, preparation of the sealant: when used, the A component and the B component were mixed uniformly according to the volume ratio of 2:1 and defoamed, and cured in the environment with the temperature of 23℃ and the humidity of 50%, thus the sealant was obtained.

[0053] Example 3

[0054] The present example protects a method for preparing a two-component silicone sealant with long storage period.

[0055] The method of the present example specifically comprises the following steps:

[0056] Step 1, preparation of A component: 100 parts of 1500 cps polydimethylsiloxane terminated by multi-alkoxy, 90 parts of active nano calcium carbonate, 10 parts of heavy calcium carbonate were put into a kneader in turn, and kneaded for 2 hours under the temperature of 105-130℃ and the vacuum degree of -0.09MPa to -0.1MPa, then 2.5 parts of calcium oxide and 2.5 parts of molecular sieve were put into the kneader, and the kneading was continued for 1 hour under the temperature of 105-120℃ and the vacuum degree of -0.09MPa to -0.1MPa, thus the base material was obtained; the base material was cooled to 60℃ under the vacuum degree of -0.09MPa to -0.1MPa, and 8 parts of tetrabutyl ketoxime silane was continuously added, and kneaded for 1 hour under the temperature of 50-65℃ and the vacuum degree of -0.09MPa to -0.1MPa, thus the modified base material was obtained.

[0057] Step 2, preparation of B component:

[0058] ① Put 100 parts of 1500 cps polydimethylsiloxane terminated by polyalkylene oxide, 80 parts of active nano calcium carbonate, 20 parts of heavy calcium carbonate into a kneader in turn, knead for 2 h under the temperature of 105-130℃ and the vacuum degree of -0.09MPa to -0.1MPa, then put 2.5 parts of calcium oxide and 2.5 parts of molecular sieve into the kneader, continue to knead for 1 h under the temperature of 105-120℃ and the vacuum degree of -0.09MPa to -0.1MPa, then the base material is obtained; continue to add 8 parts of vinyl tributanone oxime silane into the base material under the vacuum degree of -0.09MPa to -0.1MPa until the temperature of the base material is cooled to 60℃, then knead for 1 h under the temperature of 50-65℃ and the vacuum degree of -0.09MPa to -0.1MPa, then the modified base material is obtained. ② Put 15 parts of methyl triethoxysilane, 5 parts of tetraethyl orthosilicate, 8 parts of γ-aminopropyl triethoxysilane and 0.25 parts of dibutyl tin dilaurate into a reaction kettle in turn, fully stir for 1 h under the temperature of 40-60℃ and the vacuum degree of -0.09MPa to -0.1MPa. After the reaction kettle is cooled to room temperature, put 0.75 parts of dibutyl tin dilaurate into the reaction kettle, fully stir for 0.5 h under the vacuum degree of -0.09MPa to -0.1MPa, then the mixed vulcanizing agent is obtained. ③ Hydrophobic fumed silica with the specific surface area of 150m 2 / g is heated in a 105℃ oven for 24 h and is ready for use. ④ Put 200 parts of the modified base material, 8 parts of the hydrophobic fumed silica and 30 parts of the mixed vulcanizing agent into a planetary machine in turn, stir for 60 min under the vacuum degree of -0.09MPa to -0.1MPa, then the component B is obtained.

[0059] Step three, preparation of the sealant: when used, the component A and the component B are mixed uniformly according to the volume ratio of 1:1 and are defoamed, then are cured in the environment with the temperature of 23℃ and the humidity of 50%, then the sealant is obtained.

[0060] Comparative example 1

[0061] The difference between the comparative example 1 and example 1 is that no water-removing filler is added, and the other components, preparation process and parameters are the same as those of example 1.

[0062] Comparative example 2

[0063] The difference between the comparative example 2 and example 1 is that no crosslinking agent 1 is added, and the other components, preparation process and parameters are the same as those of example 1.

[0064] Comparative example 3

[0065] A preparation method of a two-component silicone sealant, specifically comprising the following steps:

[0066] Step one, preparation of A component: 100 parts of 10000 cps alpha, omega-dihydroxy polydimethylsiloxane, 20 parts of 350 cps dimethyl silicone oil, 100 parts of active nano calcium carbonate, 20 parts of heavy calcium carbonate were put into the planetary machine in turn, and stirred under the condition of vacuum degree of-0.09 MPa to-0.1 MPa for 90 min, to obtain A component.

[0067] Step two, preparation of B component: ①100 parts of 20000 cps polyalkoxy terminated polydimethylsiloxane, 80 parts of active nano calcium carbonate, 20 parts of heavy calcium carbonate were put into the kneader in turn, and kneaded under the condition of temperature 105-130 ℃, vacuum degree-0.09 MPa to-0.1 MPa for 2 h, then 2.5 parts of calcium oxide and 2.5 parts of molecular sieve were put in, and continued to knead under the condition of temperature 105-120 ℃, vacuum degree-0.09 MPa to-0.1 MPa for 1 h, to obtain the base material; the base material was cooled to 60 ℃ under the condition of vacuum degree-0.09 MPa to-0.1 MPa, and 8 parts of methyltributylketoxime silane was continuously added, and kneaded under the condition of temperature 50-65 ℃, vacuum degree-0.09 MPa to-0.1 MPa for 1 h, to obtain the modified base material. ②The hydrophobic white carbon black with specific surface area of 150 m 2 / g was heated and treated in the oven at 105 ℃ for 24 h, for standby use. ③200 parts of the above modified base material, 5 parts of the above hydrophobic white carbon black, 15 parts of methyltrimethoxysilane, 5 parts of ethyl silicate, 8 parts of γ-aminopropyl triethoxysilane and 1 part of dibutyltin dilaurate were put into the planetary machine in turn, and stirred under the condition of vacuum degree-0.09 MPa to-0.1 MPa for 60 min, to obtain B component.

[0068] Step three, preparation of sealant: when used, the above A component and B component were mixed uniformly according to the volume ratio of 1:1 and defoamed, and cured in the environment with temperature of 23 ℃ and humidity of 50%.

[0069] Comparative example 4

[0070] A preparation method of a two-component silicone sealant, specifically comprising the following steps:

[0071] Step one, preparation of A component: 100 parts of 10000 cps alpha, omega-dihydroxy polydimethylsiloxane, 20 parts of 350 cps dimethyl silicone oil, 100 parts of active nano calcium carbonate, 20 parts of heavy calcium carbonate were put into the planetary machine in turn, and stirred under the condition of vacuum degree of-0.09 MPa to-0.1 MPa for 90 min, to obtain A component.

[0072] Step two, preparation of B component:

[0073] Step 1: 100 parts of 20000 cps polydimethylsiloxane terminated by polyalkyloxy, 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 were put into a kneader in turn, and kneaded for 2 hours under the conditions of temperature 105-120°C and vacuum degree -0.09 MPa to -0.1 MPa, to obtain a base material; the base material was cooled to 60°C under the vacuum degree of -0.09 MPa to -0.1 MPa, and 8 parts of methyltributylketoxime silane was continuously added, and kneaded for 1 hour under the conditions of temperature 50-65°C and vacuum degree -0.09 MPa to -0.1 MPa, to obtain a modified base material. Step 2: 15 parts of methyltrimethoxysilane, 5 parts of tetraethyl orthosilicate, 8 parts of γ-aminopropyltriethoxysilane and 0.25 parts of dibutyltin dilaurate were put into a reaction kettle in turn, and stirred for 1 hour under the conditions of temperature 40-60°C and vacuum degree -0.09 MPa to -0.1 MPa. After cooling to room temperature, 0.75 parts of dibutyltin dilaurate was put into the reaction kettle, and stirred for 0.5 hour under the vacuum degree of -0.09 MPa to -0.1 MPa, to obtain a mixed vulcanizing agent. Step 3: hydrophobic fumed silica with specific surface area of 150 m 2 / g was heated in an oven at 105°C for 24 hours, and was used as prepared. Step 4: 200 parts of the modified base material, 5 parts of the hydrophobic fumed silica and 25 parts of the mixed vulcanizing agent were put into a planetary mixer in turn, and stirred for 60 minutes under the vacuum degree of -0.09 MPa to -0.1 MPa, to obtain component B.

[0074] Step 3: preparation of the sealant: when used, the component A and the component B were mixed uniformly in the volume ratio of 1:1 and were defoamed, and were cured in the environment with temperature of 23°C and humidity of 50%.

[0075] Comparative Example 5

[0076] The difference between Example 2 and Comparative Example 5 is that, in the preparation of component B, hydrophilic fumed silica with specific surface area of 150 m 2 / g was heated in an oven at 105°C for 24 hours, and the other components, the preparation process and the parameters were the same as those of Example 2.

[0077] Comparative Example 6

[0078] The difference between Example 3 and Comparative Example 6 is that, in the preparation of component B, all the water-filling fillers were calcium oxide. The other components, the preparation process and the parameters were the same as those of Example 3.

[0079] Comparative Example 7

[0080] The difference between Example 3 and Comparative Example 7 is that, in the preparation of component B, all the water-filling fillers were molecular sieve. The other components, the preparation process and the parameters were the same as those of Example 3.

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

[0082] The tensile strength test was in accordance with the standard GB / T 528-2009, the pull-out time test was in accordance with the standard GB 16776-2005 Appendix D.5, the table dry time test was in accordance with the standard GB / T 13477.5-2002, and the consistency test was in accordance with the standard GB / T 1749-1979.

[0083] Table 1 Performance test results of the two-component silicone sealant of Examples 1-4

[0084]

[0085] Table 2 Performance test results of the two-component silicone sealant of Comparative Examples 1-7

[0086]

[0087]

[0088] Note: "Gel" refers to the state that the silicone sealant is partially cross-linked to form an elastomer in the glue bottle and cannot be extruded.

[0089] From the comparison of the results of the examples and the comparative examples, it can be seen that the physical and chemical water removal method for treating the base material can effectively reduce the water content of the base material, the selected hydrophobic white carbon black can achieve reinforcement without significantly affecting the storage period, the cross-linking agent, the coupling agent and the catalyst after pretreatment also have excellent stability, so that the storage period of the prepared B component can reach more than 12 months, the B component does not thicken during storage, and the mechanical strength does not decrease.

[0090] Comparative Example 1 does not add water filler, the obtained two-component silicone sealant is thickened obviously at 6 months and gels at 12 months; Comparative Example 2 does not add crosslinker 1 for pre-crosslinking, the obtained two-component silicone sealant is thickened at 6 months and gels obviously at 12 months. Comparative Example 3 does not pre-treat crosslinker, coupling agent and catalyst, the obtained two-component silicone sealant has a slow curing rate at 6 months, the curing rate is significantly reduced at 12 months and the strength is significantly reduced due to incomplete crosslinking. Comparative Example 4 does not use physical dehydration treatment base and directly uses chemical dehydration treatment base, the obtained two-component silicone sealant is thickened obviously at 6 months and gels at 12 months. Comparative Example 5 uses hydrophilic white carbon black as reinforcing filler, the obtained silicone sealant is thickened obviously at 12 months and the curing rate is significantly reduced. This shows that water 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-capping of the ketoxime type crosslinker can also effectively remove the incompletely capped Si-OH groups in the 107 sealant, thereby reducing the reactivity in the subsequent storage process. The pre-treatment of crosslinker, coupling agent and catalyst can perform side reactions in advance, and the intermediates formed will not continue to affect the catalytic activity, which makes the prepared two-component silicone sealant have a 12-month super-long storage period, does not thicken during storage, and maintains excellent curing rate and mechanical properties.

[0091] Comparative Examples 6 and 7 use calcium oxide and molecular sieve as water removal fillers. The two-component silicone sealant obtained in Comparative Example 6 does not thicken and has a better curing rate, but the strength is significantly reduced. The two-component silicone sealant obtained in Comparative Example 7 is stored well, but gels at 12 months. This shows that the combination of calcium oxide and molecular sieve can effectively reduce the amount of calcium oxide, reduce the alkalinity of the silicone sealant, and make the prepared two-component silicone sealant maintain excellent mechanical properties during storage.

[0092] The above is a preferred embodiment of the present application. It should be noted that those skilled in the art can make some improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A two-component silicone sealant with a long shelf life, characterized in that, It includes component A and component B, and the volume ratio of component A to component B is 1:1 to 2:1; Component A, by weight, comprises the following components: 100 parts of α,ω-dihydroxypolydimethylsiloxane 5-30 parts of dimethyl silicone oil 80-100 parts of active nano calcium carbonate 10-30 parts of heavy calcium carbonate; Based on parts by weight, component B comprises the following components: 100 parts of polyalkoxy-terminated polydimethylsiloxane 70-90 parts of active nano calcium carbonate 10-30 parts of heavy calcium carbonate 5-8 parts of water removal filler 5-10 parts of hydrophobic silica Crosslinking agent 1 5~10 parts Crosslinking agent 2 15~30 parts 5-15 parts of coupling agent Catalyst 0.5~2 parts; The dehydrating filler is a mixture of calcium oxide and molecular sieve activated powder; the crosslinking agent 1 is at least one of methyl tributanone oxime silane, vinyl tributanone oxime silane, phenyl tributanone oxime silane, and tetrabutylone oxime silane; the crosslinking agent 2 is at least two of tetraethyl orthosilicate, propyl orthosilicate, butyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane; the method for preparing the long-shelf-life two-component silicone sealant includes the following steps: S1: α,ω-dihydroxypolydimethylsiloxane, dimethyl silicone oil, active nano-calcium carbonate, and heavy calcium carbonate are sequentially added into a planetary machine and stirred for 60 to 90 min under a vacuum of -0.09 MPa to -0.1 MPa to prepare component A. S2: Specifically includes the following steps: S2.1 Polyalkoxy-terminated polydimethylsiloxane, activated nano-calcium carbonate, and heavy calcium carbonate are sequentially added to a kneader and kneaded for 2 hours at a temperature of 105~130 ℃ and a vacuum degree of -0.09 MPa to -0.1 MPa. Then, dehydrating filler is added, and kneading is continued for 1 hour at a temperature of 105~120 ℃ and a vacuum degree of -0.09 MPa to -0.1 MPa to obtain the base material. S2.2 The base material is cooled to 50~65 ℃ under a vacuum of -0.09 MPa to -0.1 MPa, crosslinking agent 1 is added, and kneaded for 1 h at a temperature of 50~65 ℃ and a vacuum of -0.09 MPa to -0.1 MPa to obtain the modified base material; S2.3 Crosslinking agent 2, coupling agent, and one-quarter catalyst are sequentially added to the reactor and stirred thoroughly for 1 h at a temperature of 40~60 ℃ and a vacuum degree of -0.09 MPa to -0.1 MPa. After cooling to room temperature, the remaining three-quarters catalyst is added and stirred thoroughly for 0.5 h at a vacuum degree of -0.09 MPa to -0.1 MPa to obtain a mixed vulcanizing agent. S2.4 The hydrophobic silica was heated in an oven at 105 ℃ for 24 h and then set aside for later use. S2.5 The modified base material, the heat-treated hydrophobic silica, and the mixed sulfiding agent are sequentially added into a planetary machine and stirred for 60 to 90 min under a vacuum of -0.09 MPa to -0.1 MPa to prepare component B. S3: Mix component A and component B evenly at a volume ratio of 1:1 to 2:1 and degas, then cure at room temperature to prepare a two-component silicone sealant.

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

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

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

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

6. The long-shelf-life two-component silicone sealant according to claim 1, characterized in that, The particle size of the water removal packing is 10~100 μm; the mixing ratio of calcium oxide and molecular sieve activated powder is 1:1 to 1:

2.

7. The long-shelf-life two-component silicone sealant according to claim 1, characterized in that, The specific surface area of ​​the hydrophobic silica is 150~200 m². 2 / g.

8. The long-shelf-life two-component silicone sealant 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 diacetylacetone, and dioctyltin dilaurate.

9. A method for preparing a long-shelf-life two-component silicone sealant according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1: α,ω-dihydroxypolydimethylsiloxane, dimethyl silicone oil, active nano-calcium carbonate, and heavy calcium carbonate are sequentially added into a planetary machine and stirred for 60 to 90 min under a vacuum of -0.09 MPa to -0.1 MPa to prepare component A. S2: Specifically includes the following steps: S2.1 Polyalkoxy-terminated polydimethylsiloxane, activated nano-calcium carbonate, and heavy calcium carbonate are sequentially added to a kneader and kneaded for 2 hours at a temperature of 105~130 ℃ and a vacuum degree of -0.09 MPa to -0.1 MPa. Then, dehydrating filler is added, and kneading is continued for 1 hour at a temperature of 105~120 ℃ and a vacuum degree of -0.09 MPa to -0.1 MPa to obtain the base material. S2.2 The base material is cooled to 50~65 ℃ under a vacuum of -0.09 MPa to -0.1 MPa, crosslinking agent 1 is added, and kneaded for 1 h at a temperature of 50~65 ℃ and a vacuum of -0.09 MPa to -0.1 MPa to obtain the modified base material; S2.3 Crosslinking agent 2, coupling agent, and one-quarter catalyst are sequentially added to the reactor and stirred thoroughly for 1 h at a temperature of 40~60 ℃ and a vacuum degree of -0.09 MPa to -0.1 MPa. After cooling to room temperature, the remaining three-quarters catalyst is added and stirred thoroughly for 0.5 h at a vacuum degree of -0.09 MPa to -0.1 MPa to obtain a mixed vulcanizing agent. S2.4 The hydrophobic silica was heated in an oven at 105 ℃ for 24 h and then set aside for later use. S2.5 The modified base material, the heat-treated hydrophobic silica, and the mixed sulfiding agent are sequentially added into a planetary machine and stirred for 60 to 90 min under a vacuum of -0.09 MPa to -0.1 MPa to prepare component B. S3: Mix component A and component B evenly at a volume ratio of 1:1 to 2:1 and degas, then cure at room temperature to prepare a two-component silicone sealant.

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