Low moisture cure de-alcoholized silicone sealant and method of making same

Abstract

The application provides a low-humidity curing dealcoholization type silicone sealant and a preparation method thereof, which comprises the following components in mass fraction: alpha, omega-dihydroxypolydimethylsiloxane 100 parts, nano calcium carbonate 70-140 parts, dimethyl silicone oil 3-10 parts, modified silicone oil 1-4 parts, composite crosslinking agent 3-10 parts, coupling agent A 0.5-2 parts, coupling agent B 0.5-1.5 parts, and titanate catalyst 2-6 parts; the coupling agent A is one or a mixture of several of gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, gamma-aminopropyltrimethoxysilane and gamma-aminopropylmethyldiethoxysilane; the coupling agent B is one or a mixture of the two of epoxysilane oligomer and aminosilane oligomer, the structure of the coupling agent B is shown in the following formula I, II and III, and the mass ratio of the coupling agent A to the coupling agent B is 0.9-1.3:1. The silicone sealant prepared by the method can be quickly cured, the maintenance time is shortened, and the construction efficiency in winter is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of silicone sealant, and particularly relates to a low-humidity curing dealcoholized silicone sealant and a preparation method thereof. BACKGROUND

[0002] Condensation type one-component room temperature vulcanized (RTV-1) silicone sealant is a paste-like substance prepared by mixing hydroxyl-terminated polydimethylsiloxane as a base polymer, fillers, plasticizers, cross-linking agents, coupling agents, catalysts and the like in a container isolated from moisture, and is cured to form an elastomeric silicone rubber at room temperature by reacting with water in the air. Silicone sealant has advantages such as high and low temperature resistance, weathering resistance, electrical insulation, non-toxicity and physiological inertness, and the dealcoholized silicone sealant has the characteristics of no irritating odor and no corrosion to the substrate, and is widely used in the fields of building, home decoration and electronic appliances.

[0003] For example, the Chinese patent document with the publication number CN117447506A discloses a modifier, modified nano calcium carbonate, dealcoholized silicone sealant and a preparation method thereof. The modifier is obtained by the reaction of tris[3-(trimethoxysilyl)propyl]isocyanurate with hydroxymethyl diphenyl silane. The modified nano calcium carbonate is obtained by the reaction of the modifier and nano calcium carbonate. The filler in the single-component dealcoholized silicone sealant is the modified nano calcium carbonate. After tris[3-(trimethoxysilyl)propyl]isocyanurate and hydroxymethyl diphenyl silane are heated and stirred and mixed, a modifier is prepared, the nano calcium carbonate is surface treated and modified by using the modifier, and the modified nano calcium carbonate is used in the single-component dealcoholized silicone sealant, so that the internal mutual adhesion of the glue can be effectively reduced, and the tensile resistance of the silicone sealant is obviously improved.

[0004] The condensation type one-component silicone sealant needs to absorb moisture in the air and is gradually cured from the outside to the inside. The existing dealcoholized silicone sealant generally has the disadvantages of slow deep curing, long tack-free time and low initial adhesion strength, which is particularly obvious in the low temperature and low humidity environment in winter, and greatly affects the construction efficiency.

[0005] Therefore, in view of the problem, a dealcoholized silicone sealant with good moisture absorption, high water vapor transmission rate in the curing process, short tack-free time, fast deep curing, and fast initial adhesion speed and high strength is needed to be developed. SUMMARY

[0006] The technical problem solved by the present application is to provide a low-humidity curing dealcoholized silicone sealant and a preparation method thereof, and the purpose is to solve the problems of slow deep curing, long tack-free time and low initial adhesion strength of the existing dealcoholized silicone sealant.

[0007] To solve the above problems, the first aspect of the present application provides a low-humidity curing dealcoholization type silicone sealant, comprising the following components by mass fraction:

[0008] 100 parts of alpha, omega-dihydroxypolydimethylsiloxane, 70-140 parts of nano calcium carbonate, 3-10 parts of dimethyl silicone oil, 1-4 parts of modified silicone oil, 3-10 parts of composite crosslinking agent, 0.5-2 parts of coupling agent A, 0.5-1.5 parts of coupling agent B, and 2-6 parts of titanate catalyst;

[0009] The coupling agent A is one or a mixture of several of gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, gamma-aminopropyltrimethoxysilane, and gamma-aminopropylmethyldiethoxysilane.

[0010] The coupling agent B is one or a mixture of the two of epoxy silane oligomer and aminosilane oligomer, and the structure of the coupling agent B is shown in the following formula I, II, and III, wherein n=0-4 in formula I, n=0-4 in formula II, and n=4-6 in formula III.

[0011]

[0012] The mass ratio of the coupling agent A to the coupling agent B is 0.9-1.3:1.

[0013] Preferably, the components include the following by mass fraction: 100 parts of alpha, omega-dihydroxypolydimethylsiloxane, 120-140 parts of nano calcium carbonate, 4-6 parts of dimethyl silicone oil, 1-2 parts of modified silicone oil, 5-7 parts of composite crosslinking agent, 0.8-1.5 parts of coupling agent A, 0.8-1.2 parts of coupling agent B, and 3-5 parts of titanate catalyst.

[0014] Preferably, the components include the following by mass fraction: 100 parts of alpha, omega-dihydroxypolydimethylsiloxane, 120 parts of nano calcium carbonate, 5 parts of dimethyl silicone oil, 2 parts of modified silicone oil, 6 parts of composite crosslinking agent, 0.8 parts of coupling agent A, 1.2 parts of coupling agent B, and 4 parts of titanate catalyst.

[0015] Preferably, the structure of the modified silicone oil is shown in the following formula IV:

[0016]

[0017] Preferably, the mass ratio of the dimethyl silicone oil to the modified silicone oil is 2.5-4:1.

[0018] Preferably, the viscosity of the alpha, omega-dihydroxypolydimethylsiloxane is 20,000-80,000 mPa·s, and the particle size of the nano calcium carbonate is 50-200 nm.

[0019] Preferably, the dimethyl silicone oil has a viscosity of 300-500 mPa·s; the modified silicone oil is polyethylene glycol modified hydroxyl silicone oil, and has a viscosity of 300-800 mPa·s.

[0020] Preferably, the titanate catalyst is one or a mixture of two or more of diisopropoxy bis(ethoxyacetoacetyl) titanium, di-n-butoxy bis(ethoxyacetoacetyl) titanium and tetraisopropyl titanate; and the crosslinking agent is at least two of tetraethyl orthosilicate, tetra-n-propyl orthosilicate, polyethylene silicate, methyltrimethoxysilane, methyltriethoxysilane and polymethyltriethoxysilane oligomer.

[0021] The second aspect of the present application provides a preparation method of the low-humidity curing dealcoholization type silicone sealant as described above, comprising the following steps:

[0022] S1: mixing alpha, omega-dihydroxypolydimethylsiloxane, dimethyl silicone oil and nano calcium carbonate to obtain a base material;

[0023] S2: mixing a composite crosslinking agent and coupling agent A to obtain a mixed treatment product;

[0024] S3: mixing the base material, modified silicone oil, the mixed treatment product, coupling agent B and titanate catalyst to obtain the low-humidity curing dealcoholization type silicone sealant.

[0025] Preferably, step S1 specifically comprises the following steps: adding the alpha, omega-dihydroxypolydimethylsiloxane, the dimethyl silicone oil and the nano calcium carbonate into a kneader, the temperature is 100-150℃, the vacuum degree is -0.09 to -0.1 MPa, and the dehydration blending is performed for 2-3 h to obtain the base material, which is cooled for standby;

[0026] Step S2 specifically comprises the following steps: stirring and refluxing the composite crosslinking agent and the coupling agent A at 100-120℃ for 12-48 h, and then cooling to 30-40℃ to obtain the mixed treatment product;

[0027] Step S3 specifically comprises the following steps: adding the above base material, the modified silicone oil, the mixed treatment product, the coupling agent B and the titanate catalyst into a planetary mixer at 10-30℃, and stirring at a temperature of 30-50℃ and a vacuum degree of -0.09 to -0.1 MPa for 1-3 h to obtain the low-humidity curing dealcoholization type silicone sealant.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The low-humidity curing, alcohol-free silicone sealant of this invention employs a specific crosslinking agent and coupling agent process. It utilizes a compounded crosslinking agent and coupling agent, activated by reflux, and incorporates a specific proportion of highly active coupling agent. This results in a high concentration of functional groups, low water consumption in the hydrolysis reaction, and a rapid process, significantly improving the coupling bonding speed and initial bond strength. During low-humidity winter construction, it can greatly shorten curing time and improve construction efficiency.

[0030] The low-humidity curing de-alcoholized silicone sealant of the present invention is a hygroscopic silicone sealant that, when exposed to air, can quickly absorb the moisture required for the hydrolysis reaction of crosslinking agents and coupling agents, promote crosslinking curing and coupling bonding, meet the requirements of winter construction, and improve the efficiency of winter construction. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] The first aspect of this invention provides a low-moisture-curing, alcohol-free silicone sealant, comprising the following components in parts by weight:

[0033] 100 parts of α,ω-dihydroxypolydimethylsiloxane, 70-140 parts of nano-calcium carbonate, 3-10 parts of dimethyl silicone oil, 1-4 parts of modified silicone oil, 3-10 parts of composite crosslinking agent, 0.5-2 parts of coupling agent A, 0.5-1.5 parts of coupling agent B, and 2-6 parts of titanate catalyst.

[0034] Wherein, the coupling agent A is one or a mixture of several of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropylmethyldiethoxysilane.

[0035] The coupling agent B is one or a mixture of two of epoxy silane oligomers and amino silane oligomers. The structure of the coupling agent B is shown in Formula I, II, and III below, where n = 0 to 4 in Formula I; n = 0 to 4 in Formula II; and n = 4 to 6 in Formula III.

[0036]

[0037] The mass ratio of coupling agent A to coupling agent B is 0.9 to 1.3:1.

[0038] The low-moisture curing, alcohol-free silicone sealant of this invention is a hygroscopic silicone sealant in which polyethylene glycol-modified hydroxyl silicone oil (structure as shown in Formula IV) is uniformly dispersed. Its polyether segments have good hydrophilicity and hygroscopicity. When the silicone sealant is exposed to air, it can quickly absorb the moisture required for the hydrolysis reaction of the crosslinking agent and coupling agent, promoting crosslinking curing and coupling bonding, meeting the requirements for winter construction, and improving the efficiency of winter construction.

[0039] The low-humidity curing, alcohol-free silicone sealant of this invention employs a compound of silane coupling agents and specific highly active coupling agents, along with a specific crosslinking agent. It features a high concentration of functional groups and a rapid hydrolysis reaction with low water consumption. In contrast, silane monomer coupling agents with high functional group concentrations result in a slow hydrolysis coupling process with high water consumption, poor initial adhesion, and decreased initial bond strength. This invention utilizes a hygroscopic modified silicone oil and a specific crosslinking agent / coupling agent system. The resulting alcohol-free silicone sealant exhibits faster crosslinking and curing speeds, faster initial bonding speeds, and higher initial bond strength in low-humidity environments, significantly improving coupling bonding speed and initial bond strength. This greatly shortens curing time and improves construction efficiency during low-humidity winter construction.

[0040] In some embodiments, the components include the following parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane, 120-140 parts of nano-calcium carbonate, 4-6 parts of dimethyl silicone oil, 1-2 parts of modified silicone oil, 5-7 parts of composite crosslinking agent, 0.8-1.5 parts of coupling agent A, 0.8-1.2 parts of coupling agent B, and 3-5 parts of titanate catalyst.

[0041] In some embodiments, the components include the following parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane, 120 parts of nano-calcium carbonate, 5 parts of dimethyl silicone oil, 2 parts of modified silicone oil, 6 parts of composite crosslinking agent, 0.8 parts of coupling agent A, 1.2 parts of coupling agent B, and 4 parts of titanate catalyst.

[0042] In some embodiments, the modified silicone oil has the structure of Formula IV:

[0043]

[0044] In some embodiments, the mass ratio of the dimethyl silicone oil to the modified silicone oil is 2.5 to 4:1.

[0045] In some embodiments, the viscosity of the α,ω-dihydroxypolydimethylsiloxane is 20,000 to 80,000 mPa·s; and the particle size of the nano-calcium carbonate is 50 to 200 nm.

[0046] In some embodiments, the viscosity of the dimethyl silicone oil is 300-500 mPa·s; the modified silicone oil is polyethylene glycol-modified hydroxyl silicone oil with a viscosity of 300-800 mPa·s.

[0047] In some embodiments, the titanate catalyst is one or a mixture of several of diisopropoxydi(ethoxyacetyl)titanium, di-n-butoxydi(ethoxyacetyl)titanium, and tetraisopropionate titanate; the crosslinking agent is at least two of tetraethyl orthosilicate, propyl orthosilicate, polyethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, and polymethyltriethoxysilane oligomers.

[0048] A second aspect of this invention provides a method for preparing the low-moisture curing, alcohol-free silicone sealant as described above, comprising the following steps:

[0049] S1: Mix α,ω-dihydroxypolydimethylsiloxane, dimethyl silicone oil, and nano-calcium carbonate to obtain the base material;

[0050] S2: Mix the composite crosslinking agent and coupling agent A to obtain the mixed treatment product;

[0051] S3: Mix the base material, modified silicone oil, the mixed treatment material, coupling agent B, and titanate catalyst to obtain a low-humidity curing de-alcoholized silicone sealant.

[0052] In some embodiments, step S1 specifically includes the following steps: adding the α,ω-dihydroxypolydimethylsiloxane, the dimethyl silicone oil, and the nano-calcium carbonate into a kneader, at a temperature of 100℃~150℃ and a vacuum degree of -0.09~-0.1MPa, dehydrating and blending for 2~3 hours to obtain a base material, which is then cooled for later use;

[0053] Step S2 specifically includes the following steps: stirring and refluxing the composite crosslinking agent and the coupling agent A at 100℃~120℃ for 12~48h, and then cooling to 30℃~40℃ to obtain a mixed treatment product;

[0054] Step S3 specifically includes the following steps: at 10-30°C, the above base material, the modified silicone oil, the mixed treatment material, the coupling agent B, and the titanate catalyst are added to a planetary mixer and stirred for 1-3 hours at a temperature of 30°C-50°C and a vacuum degree of -0.09--0.1MPa to obtain the low-humidity curing de-alcoholized silicone sealant.

[0055] The low-humidity curing, alcohol-free silicone sealant of this invention employs a specific crosslinking agent and coupling agent process. It utilizes a compound crosslinking agent and coupling agent, activated by reflux, and incorporates a specific proportion of highly active coupling agent. This results in a high concentration of functional groups, low water consumption in the hydrolysis reaction, and a rapid process, significantly improving the coupling bonding speed and initial bond strength. During low-humidity winter construction, it can greatly shorten curing time and improve construction efficiency.

[0056] The α,ω-dihydroxypolydimethylsiloxane used in the following examples and comparative examples was purchased from China Bluestar (Group) Co., Ltd., model 107 adhesive; the modified silicone oil was purchased from Anhui Mingyi Silicon Industry Co., Ltd., model MY 1291; γ-glycidyl etheroxypropyltrimethoxysilane was purchased from Hubei Jianghan New Material Co., Ltd., model JH-O187; the epoxy silane oligomer was purchased from Hubei Jianghan New Material Co., Ltd., model JH-OP17; and the aminosilane oligomer was purchased from Hubei Jianghan New Material Co., Ltd., model JH-AP1234.

[0057] Example 1

[0058] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this embodiment includes the following steps:

[0059] S1: Take 100 parts of α,ω-dihydroxy polydimethylsiloxane with a viscosity of 50000 mPa·s, 5 parts of dimethyl silicone oil with a viscosity of 300 mPa·s, and 120 parts of 100 nanometer activated calcium carbonate and add them to a planetary mixer. Mix them at 120℃ and vacuum -0.095 MPa for 2 hours, and then cool them down to 30℃ to obtain the base material.

[0060] S2: Mix 3 parts of methyltrimethoxysilane, 3 parts of polymethyltriethoxysilane, and 1 part of γ-glycidyl etheroxypropyltrimethoxysilane at 120°C and reflux for 48 hours. Then, cool the mixture to 30°C in a sealed container to obtain the mixed product.

[0061] S3: Add the above base material, 2 parts of modified silicone oil with a viscosity of 500 mPa·s (structure as shown in Formula IV), the mixed treatment material, 1 part of hydroxyl-terminated hexaaminoethyliminopropylmethoxysilane (structure as shown in Formula III), and 4 parts of diisopropoxydi(ethoxyacetyl)titanium to a planetary machine, and stir for 1 h at 40 °C and vacuum -0.09 MPa to obtain a de-alcoholized silicone sealant.

[0062] Example 2

[0063] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this embodiment includes the following steps:

[0064] S1: Take 100 parts of α,ω-dihydroxy polydimethylsiloxane with a viscosity of 80000 mPa·s, 6 parts of dimethyl silicone oil with a viscosity of 300 mPa·s, and 90 parts of 100 nanometer activated calcium carbonate and add them to a planetary mixer. Mix them at 120℃ and vacuum -0.095 MPa for 2 hours, and then cool them down to 30℃ to obtain the base material.

[0065] S2: 3 parts of methyltriethoxysilane, 2 parts of propyl orthosilicate, and 1.5 parts of γ-glycidoxypropyltrimethoxysilane were stirred and refluxed at 120°C for 48 hours, and then the mixture was cooled to 30°C in a sealed container to obtain the mixed product.

[0066] S3: Add the above base material, 1.5 parts of modified silicone oil with a viscosity of 500 mPa·s (structure as shown in Formula IV), the mixed treatment material, 1.2 parts of hydroxyl-terminated hexaaminoethyliminopropylmethoxysilane (structure as shown in Formula III), and 3 parts of diisopropoxydi(ethoxyacetyl)titanium to a planetary machine, and stir for 1 h at 40 °C and vacuum -0.09 MPa to obtain a de-alcoholized silicone sealant.

[0067] Example 3

[0068] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this embodiment includes the following steps:

[0069] S1: Take 100 parts of α,ω-dihydroxy polydimethylsiloxane with a viscosity of 20000 mPa·s, 4 parts of dimethyl silicone oil with a viscosity of 300 mPa·s, and 140 parts of 100 nanometer activated calcium carbonate and add them to a planetary mixer. Mix them for 2 hours at 120℃ and vacuum -0.095 MPa, and then cool them down to 30℃ to obtain the base material.

[0070] S2: 4 parts of polymethyltriethoxysilane, 3 parts of propyl orthosilicate, and 1 part of γ-aminopropyltrimethoxysilane were stirred and refluxed at 120°C for 48 hours, and then cooled to 30°C in a sealed container to obtain a mixed product.

[0071] S3: Add the above base material, 1 part of modified silicone oil with a viscosity of 500 mPa·s (structure as shown in Formula IV), the mixed treatment material, 0.8 parts of hexameric glycidyl etheroxypropyl methoxysilane (structure as shown in Formula I), and 5 parts of diisopropoxy di(ethoxyacetyl) titanium to a planetary machine, and stir for 1 h at 40 °C and vacuum -0.09 MPa to obtain a dealcoholized silicone sealant.

[0072] Example 4

[0073] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this embodiment includes the following steps:

[0074] S1: Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 50000 mPa·s, 9 parts of dimethyl silicone oil with a viscosity of 500 mPa·s, and 140 parts of 100 nanometer activated calcium carbonate and add them to a planetary mixer. Mix them for 2 hours at 120℃ and vacuum -0.095 MPa, and then cool them down to 30℃ to obtain the base material.

[0075] S2: 4 parts of methyltrimethoxysilane, 2 parts of propyl orthosilicate, and 1.1 parts of γ-aminopropylmethyldiethoxysilane were stirred and refluxed at 120°C for 48 hours, and then cooled to 30°C in a sealed container to obtain a mixed product.

[0076] S3: Add the above base material, 3 parts of modified silicone oil with a viscosity of 600 mPa·s (structure as shown in Formula IV), the mixed treatment material, 1.2 parts of hexameric glycidyl etheroxypropyl methoxysilane (structure as shown in Formula I), and 4 parts of diisopropoxy di(ethoxyacetyl) titanium to a planetary machine, and stir for 1 h at 40 °C and vacuum -0.09 MPa to obtain a dealcoholized silicone sealant.

[0077] Example 5

[0078] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this embodiment includes the following steps:

[0079] S1: Completely the same as Example 1.

[0080] S2: 3 parts of methyltrimethoxysilane, 3 parts of polymethyltriethoxysilane, and 1.2 parts of γ-glycidyl etheroxypropyltrimethoxysilane were stirred and refluxed at 120°C for 48 hours, and then cooled to 30°C in a sealed container to obtain a mixed product.

[0081] S3: Add the above base material, 2 parts of modified silicone oil with a viscosity of 500 mPa·s (structure as shown in Formula IV), the mixed treatment material, 0.8 parts of hydroxyl-terminated hexaaminoethyliminopropylmethylsilane (structure as shown in Formula III), and 4 parts of diisopropoxydi(ethoxyacetyl)titanium to a planetary machine, and stir for 1 h at 40 °C and vacuum -0.09 MPa to obtain a de-alcoholized silicone sealant.

[0082] Example 6

[0083] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this embodiment includes the following steps:

[0084] S1: Completely the same as Example 1.

[0085] S2: 3 parts of methyltrimethoxysilane, 3 parts of polymethyltriethoxysilane, and 0.8 parts of γ-glycidyl etheroxypropyltrimethoxysilane were stirred and refluxed at 120°C for 48 hours, and then cooled to 30°C in a sealed container to obtain a mixed product.

[0086] S3: Add the above base material, 2 parts of modified silicone oil with a viscosity of 500 mPa·s (structure as shown in Formula IV), the mixed treatment material, 1.2 parts of hydroxyl-terminated hexaaminoethyliminopropylmethylsilane (structure as shown in Formula III), and 4 parts of diisopropoxydi(ethoxyacetyl)titanium to a planetary machine, and stir for 1 h at 40 °C and vacuum -0.09 MPa to obtain a de-alcoholized silicone sealant.

[0087] Example 7

[0088] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this embodiment includes the following steps:

[0089] S1: Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 50000 mPa·s, 6 parts of dimethyl silicone oil with a viscosity of 300 mPa·s, and 120 parts of 100 nanometer activated calcium carbonate and add them to a planetary mixer. Mix them for 2 hours at 120℃ and vacuum -0.095 MPa, and then cool them down to 30℃ to obtain the base material.

[0090] S2: Mix 3 parts of methyltrimethoxysilane, 3 parts of polymethyltriethoxysilane, and 1 part of γ-glycidyl etheroxypropyltrimethoxysilane at 120°C and reflux for 48 hours. Then, cool the mixture to 30°C in a sealed container to obtain the mixed product.

[0091] S3; Add the above base material, 1 part of modified silicone oil with a viscosity of 500 mPa·s (structure as shown in Formula IV), the mixed treatment material, 1 part of hydroxyl-terminated hexaaminoethyliminopropylmethylsilane (structure as shown in Formula III), and 4 parts of diisopropoxydi(ethoxyacetyl)titanium to a planetary machine, and stir for 1 h at 40 °C and vacuum -0.09 MPa to obtain a dealcoholized silicone sealant.

[0092] Example 8

[0093] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this embodiment includes the following steps:

[0094] S1: Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 50000 mPa·s, 4 parts of dimethyl silicone oil with a viscosity of 300 mPa·s, and 120 parts of 100 nanometer activated calcium carbonate and add them to a planetary mixer. Mix them for 2 hours at 120℃ and vacuum -0.095 MPa, and then cool them down to 30℃ to obtain the base material.

[0095] S2: Mix 3 parts of methyltrimethoxysilane, 3 parts of polymethyltriethoxysilane, and 1 part of γ-glycidyl etheroxypropyltrimethoxysilane at 120°C and reflux for 48 hours. Then, cool the mixture to 30°C in a sealed container to obtain the mixed product.

[0096] S3: Add the above base material, 3 parts of modified silicone oil with a viscosity of 500 mPa·s (structure as shown in Formula IV), the mixed treatment material, 1 part of hydroxyl-terminated hexaaminoethyliminopropylmethylsilane (structure as shown in Formula III), and 4 parts of diisopropoxydi(ethoxyacetyl)titanium to a planetary machine, and stir for 1 h at 40 °C and vacuum -0.09 MPa to obtain a de-alcoholized silicone sealant.

[0097] Comparative Example 1

[0098] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this comparative example includes the following steps:

[0099] S1: Completely the same as Example 1;

[0100] S2: Completely the same as Example 1;

[0101] S3; The above base material, the mixed treatment material, 1 part of hydroxyl-terminated hexaaminoethyliminopropylmethoxysilane, and 4 parts of diisopropoxydi(ethoxyacetyl)titanium alloy were added to a planetary machine and stirred at 40°C and vacuum -0.09MPa for 1 hour to obtain a de-alcoholized silicone sealant.

[0102] Comparative Example 2

[0103] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this comparative example includes the following steps:

[0104] S1: Completely the same as Example 1;

[0105] S2: 3 parts of methyltrimethoxysilane, 3 parts of polymethyltriethoxysilane, and 2 parts of γ-glycidyl etheroxypropyltrimethoxysilane were stirred and refluxed at 120°C for 48 hours, and then the mixture was cooled to 30°C in a sealed container to obtain the mixed treatment product.

[0106] S3: Add the above base material, 2 parts of modified silicone oil with a viscosity of 500 mPa·s, the mixed treatment material, and 4 parts of diisopropoxydi(ethoxyacetyl)titanium to a planetary machine, and stir for 1 h at 40°C and vacuum -0.09 MPa to obtain a dealcoholized silicone sealant.

[0107] Comparative Example 3

[0108] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this comparative example includes the following steps:

[0109] S1: Completely the same as Example 1;

[0110] S2; 3 parts of methyltrimethoxysilane, 3 parts of polymethyltriethoxysilane, and 2 parts of γ-glycidyl etheroxypropyltrimethoxysilane were stirred and refluxed at 120°C for 48 hours, and then the mixture was cooled to 30°C in a sealed container to obtain the mixed treatment product.

[0111] S3: Add the above base material, mixed treatment material, and 4 parts of diisopropoxydi(ethoxyacetyl)titanium to a planetary machine, and stir for 1 hour at 40°C and vacuum -0.09MPa to obtain a dealcoholized silicone sealant.

[0112] Comparative Example 4

[0113] The preparation method of the low-moisture curing, alcohol-free silicone sealant in this comparative example includes the following steps:

[0114] S1: Completely the same as Example 1.

[0115] S2: Completely the same as Example 1.

[0116] S3: Add the above base material, 2 parts of modified silicone oil with a viscosity of 500 mPa·s (structure as shown in Formula IV), the mixed treatment material, 1 part of bis-[3-(triethoxysilyl)-propyl]-amine, and 4 parts of diisopropoxydi(ethoxyacetyl)titanium to a planetary machine, and stir for 1 h at 40 °C and vacuum -0.09 MPa to obtain a dealcoholized silicone sealant.

[0117] Curing depth: The curing depth was tested according to Method 2 (wedge groove method) specified in GB / T 32369-2015 under low temperature and low humidity conditions (15℃, 15% RH) to obtain the curing depth. Tensile bond strength: The specimens were tested using a universal tensile testing machine. The prepared specimens were cured for 7 days under low temperature and low humidity conditions (15℃, 15% RH). The tensile bond strength test was conducted according to GB / T13477.8-2017, and the average tensile strength was recorded and reported. The test results are shown in Table 1.

[0118] Table 1 Performance tests of the silicone sealants prepared in each example and comparative example

[0119]

[0120]

[0121] *CF represents cohesive failure, AF represents bond failure.

[0122] As shown in Table 1, Examples 1-8 used modified silicone oil and a crosslinking agent and coupling agent system with specific processes. These systems exhibited large curing depth, high initial strength, fast initial bonding speed, and good adhesion under low humidity conditions. Comparative Example 1 did not use modified silicone oil, resulting in poor hygroscopicity of the sealant, low crosslinking curing degree, small curing depth, and low initial strength. Comparative Example 2 did not use a coupling agent with a high concentration of functional groups, resulting in poor initial adhesion and decreased tensile bond strength. Comparative Example 3 did not use either modified silicone oil or a coupling agent with a high concentration of functional groups, resulting in a small curing depth, poor initial adhesion, and a significant decrease in initial strength. Comparative Example 4 used a silane monomer coupling agent with a high concentration of functional groups. Its hydrolysis coupling process consumed a lot of water and was slow, resulting in poor initial adhesion and decreased tensile bond strength. It is fully explained that the present invention uses a hygroscopic modified silicone oil and a crosslinking agent coupling agent system with a specific process. The resulting de-alcoholized silicone sealant has a faster crosslinking and curing speed, a faster initial bonding speed and a higher initial bonding strength in low humidity environments, which can meet the requirements of winter construction.

[0123] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A low-moisture curing, alcohol-free silicone sealant, characterized in that, The components include the following parts by mass: 100 parts of α,ω-dihydroxypolydimethylsiloxane, 70-140 parts of nano-calcium carbonate, 3-10 parts of dimethyl silicone oil, 1-4 parts of modified silicone oil, 3-10 parts of composite crosslinking agent, 0.5-2 parts of coupling agent A, 0.5-1.5 parts of coupling agent B, and 2-6 parts of titanate catalyst. Wherein, the coupling agent A is one or a mixture of several of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropylmethyldiethoxysilane. The coupling agent B is one or a mixture of two of the following: epoxy silane oligomer with model number JH-OP17 from Hubei Jianghan New Material Co., Ltd., and amino silane oligomer with model number JH-AP1234 from Hubei Jianghan New Material Co., Ltd. The mass ratio of coupling agent A to coupling agent B is 0.9~1.3:1; The modified silicone oil is a polyethylene glycol-modified hydroxyl silicone oil with a viscosity of 300–800 mPa·s; The mass ratio of the dimethyl silicone oil to the modified silicone oil is 2.5 to 4:

1.

2. The low-moisture curing, alcohol-free silicone sealant according to claim 1, characterized in that: The product comprises the following components in parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane, 120-140 parts of nano-calcium carbonate, 4-6 parts of dimethyl silicone oil, 1-2 parts of modified silicone oil, 5-7 parts of composite crosslinking agent, 0.8-1.5 parts of coupling agent A, 0.8-1.2 parts of coupling agent B, and 3-5 parts of titanate catalyst.

3. The low-moisture curing, alcohol-free silicone sealant according to claim 2, characterized in that: The product comprises the following components in parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane, 120 parts of nano-calcium carbonate, 5 parts of dimethyl silicone oil, 2 parts of modified silicone oil, 6 parts of composite crosslinking agent, 0.8 parts of coupling agent A, 1.2 parts of coupling agent B, and 4 parts of titanate catalyst.

4. The low-moisture curing, alcohol-free silicone sealant according to claim 1, characterized in that: The viscosity of the α,ω-dihydroxypolydimethylsiloxane is 20,000 to 80,000 mPa·s; The particle size of the nano-calcium carbonate is 50–200 nm.

5. The low-moisture curing, alcohol-free silicone sealant according to claim 1, characterized in that: The viscosity of the dimethyl silicone oil is 300–500 mPa·s.

6. The low-moisture curing, alcohol-free silicone sealant according to claim 1, characterized in that: The titanate catalyst is one or a mixture of several of the following: diisopropoxydi(ethoxyacetyl)titanate, di-n-butoxydi(ethoxyacetyl)titanate, and tetraisopropionate titanate. The crosslinking agent is at least two of the following: tetraethyl orthosilicate, propyl orthosilicate, polyethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, and polymethyltriethoxysilane oligomers.

7. A method for preparing a low-moisture curing, alcohol-free silicone sealant as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Mix α,ω-dihydroxypolydimethylsiloxane, dimethyl silicone oil, and nano-calcium carbonate to obtain the base material; S2: Mix the composite crosslinking agent and coupling agent A to obtain the mixed treatment product; S3: Mix the base material, modified silicone oil, the mixed treatment material, coupling agent B, and titanate catalyst to obtain a low-humidity curing de-alcoholized silicone sealant.

8. The method for preparing the low-moisture curing, alcohol-free silicone sealant according to claim 7, characterized in that: Step S1 specifically includes the following steps: adding the α,ω-dihydroxypolydimethylsiloxane, the dimethyl silicone oil, and the nano-calcium carbonate into a kneader, at a temperature of 100℃~150℃ and a vacuum degree of -0.09~-0.1MPa, dehydrating and mixing for 2~3 hours to obtain the base material, which is then cooled for later use; Step S2 specifically includes the following steps: stirring and refluxing the composite crosslinking agent and the coupling agent A at 100℃~120℃ for 12~48h, and then cooling to 30℃~40℃ to obtain a mixed treatment product; Step S3 specifically includes the following steps: at 10~30℃, the above base material, the modified silicone oil, the mixed treatment material, the coupling agent B, and the titanate catalyst are added to a planetary machine and stirred for 1~3h at a temperature of 30℃~50℃ and a vacuum degree of -0.09~-0.1MPa to obtain the low-humidity curing de-alcoholized silicone sealant.

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