A fast-curing alcohol-free silicone sealant and its preparation method

Abstract

The present invention provides a fast-curing alcohol-free silicone sealant, which comprises the following preparation raw materials in parts by weight: 90-110 parts of end-capped polydimethylsiloxane, 80-200 parts of inorganic filler, 2.5-50 parts of reinforcing filler, 2-12 parts of cross-linking agent, 2-8 parts of first catalyst, 0.5-3.5 parts of second catalyst, and 0.2-5 parts of coupling agent. The present invention belongs to the technical field of silicone sealants. The fast-curing alcohol-free silicone sealant provided by the present invention can significantly improve the curing speed, effectively avoid the yellowing problem of the sealant during construction and use, and improve the initial adhesion of the sealant.

Description

Technical Field

[0001] The present invention belongs to the technical field of silicone sealants, and particularly relates to a fast-curing alcohol-free silicone sealant and a preparation method thereof. Background Art

[0002] When a one-component alcohol-free silicone sealant crosslinks and cures, it needs to contact with water vapor in the air to remove small alcohol molecules. It has the characteristics of low odor, no corrosion, and environmental friendliness. In recent years, it has been widely used in the fields of wearable devices, smart homes, lighting fixtures, engineering construction, communication networks, automobile manufacturing, photovoltaic power generation, aerospace, etc.

[0003] With the increasing automation of industrial production, consumers have put forward higher requirements for the curing speed and initial adhesion of silicone sealants. Existing conventional one-component alcohol-free silicone sealants mostly use titanates or their chelates as single-functional catalysts. For example, Chinese patent applications CN 111892906A and CN 112662379A use titanates as single-functional catalysts. In order to achieve satisfactory use performance, it is usually necessary to use a relatively large amount of catalyst in actual applications, but problems such as slow deep curing, easy yellowing, insufficient initial adhesion, and poor storage stability are still likely to occur.

[0004] Therefore, it is necessary to provide a fast-curing alcohol-free silicone sealant to solve the problems such as slow deep curing and poor storage stability. Summary of the Invention

[0005] To solve the problems existing in the prior art, the inventors have conducted in-depth research on the catalyst for preparing the alcohol-free silicone sealant and its synergistic combination with other preparation raw materials, and unexpectedly found that: by using a dual-catalyst system of a first catalyst organoaluminum compound and a second catalyst titanate compound / chelates, the curing speed can be significantly increased, the addition amount of the second catalyst titanate compound in the system can be reduced, and the first catalyst organoaluminum compound itself has excellent anti-yellowing performance, so the yellowing problem of the sealant during construction and use can be effectively avoided; in addition, the first catalyst organoaluminum compound promotes the reaction of endblocked polydimethylsiloxane and the crosslinking agent to form a lightly crosslinked network, enabling the sealant to form better strength at the initial stage of curing. In addition, the organoaluminum compound can also form a good synergistic effect with the coupling agent, improving the initial adhesion of the sealant.

[0006] The object of the present invention will be further embodied and illustrated by the following detailed description.

[0007] The present invention provides a fast-curing alcohol-free silicone sealant, which comprises the following preparation raw materials in parts by weight:

[0008]

[0009] The capped polydimethylsiloxane is a compound or composition having the structure shown in Formula I:

[0010] (R 1 O) 3-a (R 2 ) a Si-R 3 -[(CH3)2SiO] n -(CH3)2Si-R 3 -Si(OR 1 ) 3-a (R 2 ) a Ⅰ

[0011] Wherein, R 1 and R 2 are substituted or unsubstituted monovalent hydrocarbon groups, R 1 and R 2 are the same or different, R 3 is an unsubstituted straight-chain hydrocarbon group, a is an integer from 0 to 2, and n is selected from integers between 50 - 1500;

[0012] The first catalyst is an organoaluminum compound or composition having the structure shown in Formula II:

[0013] Al(R 4 O) b (R 5 ) 3-b Ⅱ

[0014] Wherein, R 4 and R 5 are independently selected from: substituted or unsubstituted alkyl, alkenyl, acyl or amide groups, and b is an integer from 1 to 3;

[0015] The second catalyst is a titanate or a chelate of a titanate.

[0016] By adopting the above technical solution, the present invention uses a capped polydimethylsiloxane with a specific structure and a dual catalyst system with a specific composition, which plays a synergistic effect with the capped polydimethylsiloxane, crosslinking agent, etc., and the provided fast-curing alcohol-free silicone sealant has the advantage of significantly improved curing speed.

[0017] Preferably, the R 1 is selected from CH3; the R 2 is selected from CH2=CH; the R 3 is selected from C2H4 or C4H8; the n is selected from integers between 800 - 1500.

[0018] Preferably, the R 4 is selected from C(CH3)CHCOCH3, CCH3CHCOOC2H5 or CH(CH3)C2H5; the R 5 is selected from O-CH3CCH3.

[0019] Preferably, the fast-curing alcohol-free silicone sealant comprises the following raw materials for preparation:

[0020]

[0021] Preferably, the second catalyst comprises one or more of n-propyl titanate, isopropyl titanate, n-butyl titanate, isobutyl titanate, tert-butyl titanate, polybutyl titanate, bis(ethyl acetoacetate) diisopropyl titanate, bis(ethyl acetoacetate) di-n-butyl titanate, bis(ethyl acetoacetate) diisobutyl titanate, bis(acetylacetonato) diisopropyl titanate, bis(acetylacetonato) diisobutyl titanate, bis(acetylacetonato) ethoxyisopropoxy titanate, bis(acetylacetonato) isobutoxyisopropoxy titanate, bis(triethanolamine) diisopropyl titanate.

[0022] Preferably, the inorganic filler comprises one or more of calcium carbonate, quartz powder, talc powder, mica powder, kaolin, wollastonite, calcium silicate, barium sulfate, magnesium silicate, aluminum hydroxide, magnesium hydroxide, montmorillonite, alumina, magnesia, zinc oxide, aluminum nitride, boron nitride, aluminum powder, copper powder, nickel powder.

[0023] Preferably, the reinforcing filler comprises one or more of fumed silica, precipitated silica, methyl MQ resin, vinyl MQ resin, phenyl MQ resin.

[0024] Preferably, the crosslinking agent is an alkoxysilane or a condensate of an alkoxysilane; the alkoxysilane comprises one or more of methyltrimethoxysilane, methyltriethylsilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, methylvinyldimethoxysilane, polymethyltrimethoxysilane, polymethyltriethoxysilane, polypropyltrimethoxysilane, 1,2-bis(trimethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethane.

[0025] Preferably, the coupling agent includes vinyltris(2-methoxyethoxy)silane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, bis-[3-(trimethoxysilyl)propyl]-ethylenediamine, bis-[3-(triethoxysilyl)propyl]-ethylenediamine, N-[3-(trimethoxysilyl)propyl]-n-butylamine, N,N-dimethyl-3-aminopropyltrimethoxysilane, N-n-butyl-3-aminopropyltriethoxysilane, 3-(diethylenetriamine)propyltrimethoxysilane, hexamethyldisilazane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-cyanoethyltriethoxysilane, ureidopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, isocyanatepropyltrimethoxysilane, isocyanatepropyltriethoxysilane, 1146, SIVO 203, two or more of SIVO 260 and VPS SIVO 280.

[0026] In addition, the present invention also provides a method for preparing the fast-curing alcohol-eliminating type silicone sealant, including the following steps: 1) Adding the end-capped polydimethylsiloxane, inorganic filler, and reinforcing filler into a high-speed disperser, dehydrating and blending them for 90-180 min under the conditions of a temperature of 110-130°C and nitrogen protection, and then cooling to obtain the base material;

[0027] 2) At room temperature, adding the base material, cross-linking agent, and first catalyst obtained in step 1) into a high-speed disperser or planetary mixer, and stirring for 30-45 min under nitrogen protection; then adding the second catalyst and coupling agent, and continuously stirring for 45-60 min under nitrogen protection to prepare the fast-curing alcohol-eliminating type silicone sealant.

[0028] Compared with the prior art, the beneficial effects of the present invention include:

[0029] (1) The present invention uses a dual catalyst system with cooperative functions, which can significantly improve the curing speed of the alcohol-free silicone sealant. Among them, the first catalyst, an organoaluminum compound, can preferentially react with the residual moisture in the filler and catalyze the reaction between the crosslinking agent and the end-capped polydimethylsiloxane to form a slightly crosslinked network structure. This slightly crosslinked network structure can accelerate the subsequent curing speed of the alcohol-free silicone sealant; the second catalyst is a titanate compound. Since the titanate compound does not need to participate in the reaction between the end-capped polydimethylsiloxane and the crosslinking agent, its catalytic activity can be maximally retained. During the construction of the sealant, it can react quickly with the water vapor in the air, enabling the alcohol-free silicone sealant to achieve rapid crosslinking and curing.

[0030] (2) By using the dual catalyst system, the present invention can reduce the addition amount of the second catalyst, the titanate compound, in the system. Moreover, the first catalyst, the organoaluminum compound, itself has excellent anti-yellowing performance. Therefore, it can effectively avoid the yellowing problem of the alcohol-free silicone sealant during construction and use.

[0031] (3) The first catalyst, the organoaluminum compound, used in the present invention promotes the reaction between the end-capped polydimethylsiloxane and the crosslinking agent to form a slightly crosslinked network, enabling the alcohol-free silicone sealant to form good strength at the initial stage of curing. In addition, the organoaluminum compound can also form a good synergistic effect with the coupling agent, improving the initial adhesion of the alcohol-free silicone sealant.

[0032] (4) The curing performance of conventional single-component alcohol-free silicone sealant will decline or even be lost during storage. The reason is that the residual moisture in the system reacts with the crosslinking agent to form free alcohol, and the free alcohol can undergo an equilibration reaction with the polysiloxane in the presence of the titanate catalyst to form end groups without crosslinking function. The first catalyst, the organoaluminum compound, adopted in the present invention can effectively remove the trace residual moisture in the system and avoid the reaction between the crosslinking agent and the residual moisture to form free alcohol by catalyzing the reaction between the crosslinking agent and the end-capped polydimethylsiloxane to form a slightly crosslinked network structure. Thus, the storage stability of the alcohol-free silicone sealant is improved.

[0033] (5) The fast-curing alcohol-free silicone sealant provided by the present invention has a simple and easy preparation method, which is suitable for large-scale production and application. Detailed implementation mode

[0034] The following further elaborates on the present invention through specific examples.

[0035] In the present invention, the components involved are all conventional commercially available products or can be obtained by conventional technical means in the art. For example, the end-capped polydimethylsiloxane is purchased from Jiangsu Kexing New Materials Co., Ltd., and the first catalyst is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0036] Example 1 Fast-curing alcohol-free silicone sealant

[0037] A method for preparing a fast-curing alcohol-free silicone sealant, comprising the following steps:

[0038] (1) 100 parts by mass of endblocked polydimethylsiloxane having the structure of formula Ⅲ (kinematic viscosity at 25 °C is 10 Pa·s), 100 parts by mass of nano calcium carbonate with an average particle size of 40 nm, and 20 parts by mass of precipitated silica with a BET specific surface area of 180 m 2 / g are added to a high-speed disperser, and dehydrated and blended for 110 min under the conditions of a temperature of 115 °C and nitrogen protection, and then cooled to obtain a base material.

[0039] (CH2=CH)(CH3O)2Si-C2H4-[(CH3)2SiO] 800 -(CH3)2Si-C2H4-Si(OCH3)2(CH=CH2) Ⅲ

[0040] Al(O-C(CH3)CHC0CH3)3 Ⅳ

[0041] (2) At room temperature, the base material obtained in the above step (1), 8 parts by mass of methyltrimethoxysilane crosslinking agent, and 4 parts by mass of the first catalyst organoaluminum compound having the structure of formula Ⅳ are added to a high-speed disperser, and stirred for 30 min under the condition of nitrogen protection; then 1.3 parts by mass of the second catalyst diisopropyl bis(ethyl acetoacetate) titanate, 0.35 parts by mass of bis-[3-(trimethoxysilyl)-propyl]-ethylenediamine, and 0.75 parts by mass of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane are added, and stirring is continued for 45 min under the condition of nitrogen protection to obtain a fast-curing alcohol-free silicone sealant.

[0042] Example 2 Fast-curing alcohol-free silicone sealant

[0043] A method for preparing a fast-curing alcohol-free silicone sealant, comprising the following steps:

[0044] (1) 100 parts by mass of endblocked polydimethylsiloxane having the structure of formula Ⅴ (kinematic viscosity at 25 °C is 50 Pa·s), 80 parts by mass of nano calcium carbonate with an average particle size of 50 nm, and 2.5 parts by mass of fumed silica with a BET specific surface area of 380 m 2 / g are added to a high-speed disperser, and dehydrated and blended for 100 min under the conditions of a temperature of 125 °C and nitrogen protection, and then cooled to obtain a base material.

[0045] (CH3O)3Si-C2H4-[(CH3)2SiO]1500 -(CH3)2Si-C2H4-Si(OCH3)3 Ⅴ

[0046] Al(O-CCH3CHC0OC2H5)(O-CH3CCH3)2 Ⅵ

[0047] (2) At room temperature, put the base material obtained in the above step (1), a mixed cross-linking agent composed of 2.6 parts by mass of vinyltrimethoxysilane and 1.4 parts by mass of methylpropyldimethoxysilane, and 2.8 parts by mass of the first catalyst organoaluminum compound with the structure of formula Ⅵ into a high-speed disperser. Under the condition of nitrogen protection, stir for 45 min; then add 1.5 parts by mass of the second catalyst tetrabutyl titanate, 0.25 parts by mass of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and 0.5 parts by mass of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and continue to stir for 60 min under the condition of nitrogen protection to obtain a fast-curing alcohol-releasing silicone sealant.

[0048] Example 3 Fast-curing alcohol-releasing silicone sealant

[0049] A preparation method of a fast-curing alcohol-releasing silicone sealant, comprising the following steps:

[0050] (1) Put 60 parts by mass of end-capped polydimethylsiloxane with the structure of formula Ⅲ (kinematic viscosity at 25 °C is 10 Pa·s), 40 parts by mass of end-capped polydimethylsiloxane with the structure of formula Ⅴ (kinematic viscosity at 25 °C is 50 Pa·s), 90 parts by mass of nano calcium carbonate with an average particle size of 30 nm, and 10 parts by mass of fumed silica with a BET specific surface area of 120 m 2 / g into a high-speed disperser, dehydrate and blend for 120 min at a temperature of 120 °C under the condition of nitrogen protection, and then cool to obtain a base material.

[0051] (2) At room temperature, put the base material obtained in the above step (1), a mixed cross-linking agent composed of 5.1 parts by mass of methyltrimethoxysilane and 0.9 parts by mass of 1,2-bis(triethoxysilyl)ethane, and 3 parts by mass of the first catalyst organoaluminum compound with the structure of formula Ⅵ into a high-speed disperser. Under the condition of nitrogen protection, stir for 50 min; then add 1.6 parts by mass of the second catalyst diisobutyl titanate bis(ethyl acetoacetate), 0.4 parts by mass of 1146, 0.12 parts by mass of γ-aminopropyltriethoxysilane and 0.18 parts by mass of γ-(2,3-epoxypropoxy)propyltriethoxysilane, and continue to stir for 60 min under the condition of nitrogen protection to obtain a fast-curing alcohol-releasing silicone sealant.

[0052] Example 4 Fast-curing alcohol-releasing silicone sealant

[0053] Preparation method of fast-curing alcohol-free silicone sealant, comprising the following steps:

[0054] (1) Add 100 parts by mass of end-capped polydimethylsiloxane with the structure of formula VII (kinematic viscosity at 25 °C is 20 Pa·s), 100 parts by mass of nano calcium carbonate with an average particle size of 25 nm, 20 parts by mass of ultrafine quartz powder with an average particle size of 1 μm, and 50 parts by mass of vinyl MQ resin (commercial grade VQM881 from Hanse Cheime, kinematic viscosity at 25 °C is 800 mPa·s) into a high-speed disperser. Under the conditions of a temperature of 115 °C and nitrogen protection, dehydrate and blend for 120 min, and then cool to obtain the base material.

[0055] (CH2=CH)(CH3O)2Si-C4H8-[(CH3)2SiO] 1000 -(CH3)2Si-C4H8-Si(OCH3)2(CH=CH2)Ⅶ

[0056] Al(O-CH(CH3)C2H5)3Ⅷ

[0057] (2) At room temperature, add the base material obtained in the above step (1), 6.4 parts by mass of vinyltrimethoxysilane, 2.1 parts by mass of methyltrimethoxysilane, and a mixed cross-linking agent composed of 1.5 parts by mass of 1,2-bis(triethoxysilyl)ethane, a first catalyst composed of 4.5 parts by mass of an organoaluminum compound with the structure of formula VI and 0.9 parts by mass of an organoaluminum compound with the structure of formula VIII into a high-speed disperser. Under the condition of nitrogen protection, stir for 35 min; then add 0.9 parts by mass of the second catalyst bis(acetylacetonato)ethoxyisopropoxytitanate, 0.72 parts by mass of 1146, 0.36 parts by mass of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 0.3 parts by mass of 3-methacryloxypropyltrimethoxysilane, and continue to stir for 50 min under the condition of nitrogen protection to prepare the fast-curing alcohol-free silicone sealant.

[0058] Example 5 Fast-curing alcohol-free silicone sealant

[0059] Preparation method of fast-curing alcohol-free silicone sealant, comprising the following steps:

[0060] (1) Add 70 parts by mass of end-capped polydimethylsiloxane with the structure of formula VII (kinematic viscosity at 25 °C is 20 Pa·s), 30 parts by mass of end-capped polydimethylsiloxane with the structure of formula V (kinematic viscosity at 25 °C is 50 Pa·s), 120 parts by mass of nano calcium carbonate with an average particle size of 40 nm, and 5 parts by mass of BET specific surface area of 180 m 220 parts by mass of vinyl MQ resin (commercial grade VQM881 from Hanse Cheime, kinematic viscosity at 25 °C is 800 mPa·s) and 2.5 parts by mass of fumed silica with a BET specific surface area of 200 m² / g are added to a high-speed disperser, and dehydrated and blended under nitrogen protection at a temperature of 115 °C for 110 min, and then cooled to obtain a base material.

[0061] (2) At room temperature, the base material obtained in the above step (1), a mixed cross-linking agent composed of 3.3 parts by mass of vinyltrimethoxysilane and 5.1 parts by mass of methyltrimethoxysilane, a first catalyst composed of 2.4 parts by mass of an organoaluminum compound with the structure of formula IV and 0.54 parts by mass of an organoaluminum compound with the structure of formula VIII are added to a high-speed disperser, and stirred under nitrogen protection for 30 min; then 0.5 parts by mass of a second catalyst, isopropyl titanate, 0.9 parts by mass of SIVO 203 and 0.45 parts by mass of N-[3-(trimethoxysilyl)propyl]-n-butylamine are added, and stirring is continued for 45 min under nitrogen protection to prepare a fast-curing alcohol-releasing silicone sealant.

[0062] Example 6 Fast-curing alcohol-releasing silicone sealant

[0063] A preparation method of a fast-curing alcohol-releasing silicone sealant, comprising the following steps:

[0064] (1) 80 parts by mass of endblocked polydimethylsiloxane with the structure of formula VII (kinematic viscosity at 25 °C is 20 Pa·s), 20 parts by mass of endblocked polydimethylsiloxane with the structure of formula V (kinematic viscosity at 25 °C is 50 Pa·s), 100 parts by mass of nano calcium carbonate with an average particle size of 40 nm, 20 parts by mass of ultrafine heavy calcium carbonate with an average particle size of 2 μm, and 2.5 parts by mass of precipitated silica with a BET specific surface area of 200 m 2 ² / g are added to a high-speed disperser, and dehydrated, blended and kneaded under nitrogen protection at a temperature of 125 °C for 120 min, and then cooled to obtain a base material.

[0065] (2) At room temperature, the base material obtained in the above step (1), a mixed cross-linking agent composed of 3.2 parts by mass of vinyltrimethoxysilane and 4.8 parts by mass of methyltrimethoxysilane, 2.7 parts by mass of an organoaluminum compound with the structure of formula VIII as the first catalyst are added to a high-speed disperser, and stirred under nitrogen protection for 30 min; then 0.7 parts by mass of a second catalyst composed of isopropyl titanate and 0.9 parts by mass of tert-butyl titanate, 1.6 parts by mass of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, 1.2 parts by mass of 3-(diethylenetriamine)propyltrimethoxysilane are added, and stirring is continued for 45 min under nitrogen protection to prepare a fast-curing alcohol-releasing silicone sealant.

[0066] Comparative Example 1

[0067] The preparation method of the silicone sealant includes the following steps:

[0068] (1) Add 100 parts by mass of hydroxyl-terminated polydimethylsiloxane with the structure of formula IX (kinematic viscosity at 25 °C is 10 Pa·s), 100 parts by mass of nano calcium carbonate with an average particle size of 40 nm, and 20 parts by mass of precipitated silica with a BET specific surface area of 180 m 2 / g into a high-speed disperser, dehydrate and blend them for 120 min at a temperature of 115 °C under nitrogen protection, and then cool to obtain the base material.

[0069] HO-(CH3)2SiO-[(CH3)2SiO] 800 -Si(CH3)2-OH Ⅸ

[0070] (2) At room temperature, add the base material obtained in the above step (1), 8 parts by mass of methyltrimethoxysilane cross-linking agent, 4.5 parts by mass of diisopropyl bis(ethyl acetoacetate) titanate, 0.35 parts by mass of bis-[3-(trimethoxysilyl)-propyl]-ethylenediamine, and 0.75 parts by mass of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane into a high-speed disperser, and stir for 45 min under nitrogen protection to prepare the silicone sealant.

[0071] Comparative Example 2

[0072] The preparation method of the silicone sealant in this comparative example is basically the same as that in Example 4, except that the second catalyst bis(acetylacetonato)ethoxyisopropoxytitanate is not added in step (2).

[0073] Comparative Example 3

[0074] The preparation method of the silicone sealant in this comparative example is basically the same as that in Example 4, except that the first catalyst organoaluminum compound with the structure of formula VIII is not added in step (2), and the addition amount of bis(acetylacetonato)ethoxyisopropoxytitanate is changed to 6.3 parts.

[0075] Test Example

[0076] The silicone sealants prepared in the embodiments of the present invention and the comparative examples were compared. The surface drying time was tested according to Method B of GB / T 13477.5-2002; the curing depth was tested according to Method 2 in GB / T 32369-2015; for the test of the initial adhesion: after the specimen was cured in the standard environment for 12 h, the shear strength was tested according to GB / T 7124-2008, and the substrate was anodized aluminum; for the yellowing test: the sealant was evenly coated on the edge of a clean and transparent PC cover, then the PC cover was installed on the corresponding aluminum base with a groove, the PC cover and the base were joined, pressed tightly and sealed, and immediately placed in an oven at 100 °C. After 12 h, it was taken out and the yellowing conditions of the sealant sample and the PC cover were observed and recorded. The test results are shown in Table 1.

[0077] Table 1 Performance comparison of silicone sealants

[0078]

[0079] As can be seen from the results in Table 1, the silicone sealants prepared in Examples 1-6 have short surface drying times, fast deep curing speeds, high initial bonding strengths, do not turn yellow, and have good storage stability. Comparative Example 1 is a conventional alcohol-free silicone sealant, which uses 107 glue with a viscosity similar to that of the end-capped polydimethylsiloxane described in Example 1 as the base polymer and does not use an organoaluminum compound as the first catalyst. Its deep curing speed, initial bonding strength, and storage performance have all decreased significantly. Moreover, Comparative Example 1 only uses a titanate chelate as the catalyst and is prone to yellowing during use. The difference between Comparative Example 2 and Example 4 is that the second catalyst titanate compound is not added. Its surface drying time has decreased from 8 minutes in Example 4 to 48 minutes, and the deep curing speed has also decreased from 3.6 mm / 24 h to 1.9 mm / 24 h. In addition, the initial shear strength is only 0.28 MPa, and the storage period has also decreased to 120 days. This shows that although using only an organoaluminum compound as the catalyst can enable the sealant to form a slightly cross-linked network structure, without adding the second catalyst titanate compound, the sealant cannot achieve subsequent rapid curing smoothly, and it will also lead to a significant decrease in the storage period of the sealant. In addition, it also shows that the organoaluminum compound has excellent anti-yellowing performance, and the sealant using only the organoaluminum compound as the catalyst will not turn yellow. The difference between Comparative Example 3 and Example 4 is that the first catalyst organoaluminum compound is not added, and the addition amount of the second catalyst bis(acetylacetonato)ethoxyl isopropoxytitanate is increased to 6.3 parts. Its surface drying time is slightly slower than that of Example 4, and the deep curing speed and initial bonding strength are far inferior to those of Example 4. This shows that without adding the first catalyst organoaluminum compound, increasing the addition amount of the second catalyst titanate can improve the deep curing speed and initial adhesion of the sealant to a certain extent, but the improvement is limited, and it will cause serious yellowing of the sealant, affecting the use effect. As can be seen from Table 1, only by using a dual catalyst system composed of the first catalyst organoaluminum compound and the second catalyst titanate compound can the advantages of fast deep curing, high initial bonding strength, no yellowing, and good storage stability of the fast-curing alcohol-free silicone sealant of the present invention be achieved.

[0080] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A fast-curing alcohol-free silicone sealant, characterized in that: Comprising the following preparation raw materials in parts by weight: The capped polydimethylsiloxane is a compound or composition having the structure shown in Formula I: (R 1 O) 3-a (R 2 ) a Si-R 3 -[(CH3)2SiO] n -(CH3)2Si-R 3 -Si(OR 1 ) 3-a (R 2 ) a Ⅰ Wherein, R 1 and R 2 are a substituted or unsubstituted monovalent hydrocarbon group, R 1 and R 2 are the same or different, R 3 is an unsubstituted straight-chain hydrocarbon group, a is an integer from 0 to 2, and n is selected from integers between 50 and 1500; The first catalyst is an organoaluminum compound or composition having the structure shown in Formula II: Al(R 4 O) b (R 5 ) 3-b Ⅱ Wherein, R 4 and R 5 are each independently selected from: substituted or unsubstituted alkyl, alkenyl, acyl or amide group, and b is an integer of 1 to 3; The second catalyst is a titanate or a chelate of a titanate.

2. The fast-curing alcohol-free silicone sealant according to claim 1, wherein: The R 1 is selected from CH3; the R 2 is selected from CH2=CH; the R 3 is selected from C2H4 or C4H8; the n is an integer between 800 and 1500.

3. The fast-curing alcohol-free silicone sealant according to claim 1, wherein: The R 4 is selected from C(CH3)CHCOCH3, CCH3CHCOOC2H5 or CH(CH3)C2H5.

4. The fast-curing alcohol-free silicone sealant according to any one of claims 1 to 3, characterized in that: Comprising the following preparation raw materials:

5. The fast-curing alcohol-free silicone sealant according to any one of claims 1 to 3, characterized in that: The second catalyst includes one or more of n-propyl titanate, isopropyl titanate, n-butyl titanate, isobutyl titanate, tert-butyl titanate, polybutyl titanate, diisopropyl bis(ethyl acetoacetate) titanate, di-n-butyl bis(ethyl acetoacetate) titanate, diisobutyl bis(ethyl acetoacetate) titanate, diisopropyl bis(acetylacetone) titanate, diisobutyl bis(acetylacetone) titanate, ethoxyisopropoxy titanate bis(acetylacetone), isobutoxyisopropoxy titanate bis(acetylacetone), diisopropyl bis(triethanolamine) titanate.

6. The fast-curing alcohol-free silicone sealant according to any one of claims 1 to 3, characterized in that: The inorganic filler includes one or more of calcium carbonate, quartz powder, talc powder, mica powder, kaolin, wollastonite, calcium silicate, barium sulfate, magnesium silicate, aluminum hydroxide, magnesium hydroxide, montmorillonite, alumina, magnesia, zinc oxide, aluminum nitride, boron nitride, aluminum metal powder, copper metal powder, nickel metal powder.

7. The fast-curing alcohol-free silicone sealant according to any one of claims 1 to 3, characterized in that: The reinforcing filler includes one or more of fumed silica, precipitated silica, methyl MQ resin, vinyl MQ resin, phenyl MQ resin.

8. The fast-curing alcohol-free silicone sealant according to any one of claims 1 to 3, characterized in that: The crosslinking agent is an alkoxysilane or a condensate of an alkoxysilane; the alkoxysilane includes one or more of methyltrimethoxysilane, methyltriethylsilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, methylvinyldimethoxysilane, polymethyltrimethoxysilane, polymethyltriethoxysilane, polypropyltrimethoxysilane, 1,2-bis(trimethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethane.

9. The fast-curing alcohol-free silicone sealant according to any one of claims 1 to 3, characterized in that: The coupling agents include vinyltris(2-methoxyethoxy)silane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, bis-[3-(trimethoxysilyl)propyl]-ethylenediamine, bis-[3-(triethoxysilyl)propyl]-ethylenediamine, N-[3-(trimethoxysilyl)propyl]-n-butylamine, N,N-dimethyl-3-aminopropyltrimethoxysilane, N-n-butyl-3-aminopropyltriethoxysilane, 3-(diethylenetriamine)propyltrimethoxysilane, hexamethyldisilazane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-cyanoethyltriethoxysilane, ureidopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, isocyanatepropyltrimethoxysilane, isocyanatepropyltriethoxysilane, 1146, SIVO 203, two or more of SIVO 260, VPS SIVO280.

10. The preparation method of the fast-curing alcohol-free silicone sealant according to any one of claims 1 to 9, characterized in that: Comprising the following steps: 1) Add the capped polydimethylsiloxane, inorganic filler and reinforcing filler into a high-speed disperser, dehydrate and blend them for 90 - 180 min under the conditions of a temperature of 110 - 130 °C and nitrogen protection, and then cool to obtain a base material; 2) At room temperature, add the base material, crosslinking agent and first catalyst obtained in step 1) into a high-speed disperser or a planetary mixer, and stir for 30 - 45 min under the condition of nitrogen protection; then add the second catalyst and coupling agent, and continue to stir for 45 - 60 min under the condition of nitrogen protection to prepare a fast-curing alcohol-free silicone sealant.

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