Dealcoholized room temperature vulcanized silicone rubber and preparation method thereof

Abstract

The invention discloses dealcoholized room temperature vulcanized silicone rubber and a preparation method thereof, the dealcoholized room temperature vulcanized silicone rubber is prepared from a silica gel composition, a coupling agent, a cross-linking agent and a catalyst, and the silica gel composition is prepared from a base material, a filler and a tackifier; the base material is prepared from vinyl-terminated polydimethylsiloxane and nano active calcium carbonate modified by a surface treating agent. The dealcoholized room temperature vulcanized silicone rubber has the advantages of fast curing speed, large curing depth, high mechanical strength after curing, and good market application value.

Description

Technical Field

[0001] This invention belongs to the field of organosilicon polymer materials technology, specifically to the field of single-component organosilicon sealant technology. More specifically, this invention relates to a high-strength, deep-curing, alcohol-free room temperature vulcanizing silicone rubber and its preparation method. Background Technology

[0002] With the development of the electronics industry, higher performance requirements have been placed on sealants. Faster production efficiency demands faster curing speeds and deeper curing capabilities to meet the needs of rapid bonding of large-area enclosures and other subsequent processes. At the same time, more extreme application scenarios require adhesive sealants to possess higher bonding strength and sufficiently high mechanical strength.

[0003] De-alcoholized room temperature vulcanizing silicone rubber is a paste-like adhesive made primarily of polydimethylsiloxane, supplemented with fillers, crosslinking agents, coupling agents, and catalysts, mixed under vacuum. Due to its excellent weather resistance, high and low temperature resistance, and electrical insulation properties, it absorbs moisture from the air for crosslinking and curing during the reaction, while simultaneously releasing methanol gas. It poses extremely low harm to human health and complies with environmental regulations such as RoHS and REACH, making it widely used in the electronics, construction, and other industrial sectors.

[0004] However, dealcohol-based room temperature vulcanizing silicone rubber cures through gradual cross-linking from the outside in by contact with moisture in the air. Its curing speed is relatively slow, and because the cross-linking of the outer layer further hinders the contact of moisture with the interior, there is often a situation where the outside is completely cured while the inside is still wet, resulting in insufficient curing depth. The deep curing time of commercially available dealcohol-based room temperature vulcanizing silicone rubber is generally 2.0~3.0 mm / 24 h, not exceeding 4.0 mm / 24 h. Furthermore, its mechanical strength after curing is also insufficient. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a de-alcoholized room temperature vulcanizing silicone rubber with fast curing speed, large curing depth, and high mechanical strength after curing.

[0006] The technical solutions for achieving the above-mentioned objectives include the following.

[0007] In a first aspect, the present invention provides a dealcohol-type room temperature vulcanizing silicone rubber, prepared from the following raw materials in parts by weight:

[0008] 100 parts of silicone composition

[0009] 0.2 to 1 part coupling agent

[0010] 4 to 10 parts of crosslinking agent

[0011] 2 to 8 parts catalyst

[0012] The silicone composition is prepared from 100 parts of base material, 15-25 parts of filler, and 1-6 parts of tackifier. The base material is prepared from 100 parts of vinyl-terminated polydimethylsiloxane and 80-110 parts of nano-activated calcium carbonate modified with a surface treatment agent. The tackifier is prepared by stirring γ-aminopropyltriethoxysilane, acetoxytrimethoxysilane, and polyether silicone oil in a water bath at 50-60°C for 55-65 minutes, followed by adding polyoxyethylene phosphate and stirring for 25-35 minutes. The coupling agent is prepared by heating bis[3-(triethoxysilyl)propyl]amine, acetoxyethyltrimethoxysilane, 3-isocyanate-propyltrimethoxysilane, and water to 60-70°C and stirring for 55-65 minutes, then recovering the product, and then adding 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane to the product and stirring for 25 minutes. min~35 min.

[0013] A second aspect of the present invention provides a method for preparing the above-mentioned dealcoholized room temperature vulcanizing silicone rubber, comprising the following steps:

[0014] (1) The vinyl-terminated polydimethylsiloxane and nano-activated calcium carbonate modified with a surface treatment agent were stirred for 100 min to 140 min at a temperature of 100℃ to 150℃, a vacuum of 0.085 MPa to 0.095 MPa, and a rotation speed of 500 rpm to 800 rpm to obtain the base material;

[0015] (2) When the temperature of the base material drops below 50°C, add the filler and stir for 25 min to 35 min under vacuum of 0.085 MPa to 0.095 MPa and speed of 400 rpm to 500 rpm. Then add the thickener and continue stirring for 50 min to 70 min under vacuum of 0.085 MPa to 0.095 MPa and speed of 250 rpm to 350 rpm to obtain the silicone composition.

[0016] (3) Add crosslinking agent, catalyst and coupling agent to the silica gel composition in sequence, and continue stirring for 50 min to 70 min under vacuum of 0.085 MPa ~ 0.095 MPa and rotation speed of 250 rpm ~ 350 rpm to obtain the product.

[0017] In this invention, by adding an appropriate amount of filler to a base material made of vinyl-terminated polydimethylsiloxane and modified nano-calcium carbonate, and adding pre-prepared tackifiers and coupling agents containing specific groups, as well as crosslinking agents, catalysts and other components, and by controlling the weight ratio of each component, a de-alcoholized room temperature vulcanizing silicone rubber is prepared. This rubber has a fast curing speed, a large curing depth, and high mechanical strength after curing, and has good market application value.

[0018] In this invention, firstly, an appropriate amount of filler is added to a base material made of vinyl-terminated polydimethylsiloxane and modified nano-calcium carbonate (this controls the moisture content in the system while improving the mechanical strength and adhesion of the silicone rubber). Then, a pre-prepared tackifier is added (on the one hand, the ester groups such as polyoxyethylene phosphate and acetoxytrimethoxysilane in the tackifier can further consume some of the moisture in the binding system; on the other hand, the phosphate groups can form bonds with the vinyl groups of the vinyl-terminated polydimethylsiloxane backbone, improving the mechanical strength and reactivity of the silicone rubber). Next, a crosslinking agent, a catalyst, and a pre-prepared coupling agent are added to finally prepare a dealcoholized room temperature vulcanizing silicone rubber. The various active groups in the silicone rubber system are cleverly combined to improve the curing rate and mechanical strength of the sealant. When the silicone rubber begins to crosslink and cure upon contact with air moisture, the silicone rubber system further releases some moisture, accelerating the crosslinking and curing process and improving the performance of deep curing. Detailed Implementation

[0019] To facilitate understanding of the present invention, a more complete description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0021] Unless otherwise specified, experimental methods in the following examples are generally performed under standard conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the examples are commercially available products.

[0022] In some embodiments of the present invention, a dealcohol-type room temperature vulcanizing silicone rubber is disclosed, which is prepared from the following raw materials in parts by weight:

[0023] 100 parts of silicone composition

[0024] 0.2 to 1 part coupling agent

[0025] 4 to 10 parts of crosslinking agent

[0026] 2 to 8 parts catalyst

[0027] The silicone composition is prepared from 100 parts of base material, 15-25 parts of filler, and 1-6 parts of tackifier. The base material is prepared from 100 parts of vinyl-terminated polydimethylsiloxane and 80-110 parts of nano-activated calcium carbonate modified with a surface treatment agent. The tackifier is prepared by stirring γ-aminopropyltriethoxysilane, acetoxytrimethoxysilane, and polyether silicone oil in a water bath at 50-60°C for 55-65 minutes, followed by adding polyoxyethylene phosphate and stirring for 25-35 minutes. The coupling agent is prepared by heating bis[3-(triethoxysilyl)propyl]amine, acetoxyethyltrimethoxysilane, 3-isocyanate-propyltrimethoxysilane, and water to 60-70°C and stirring for 55-65 minutes, then recovering the product, and then adding 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane to the product and stirring for 25 minutes. min~35 min.

[0028] In one embodiment, the dealcohol-type room temperature vulcanizing silicone rubber is prepared from the following raw materials in parts by weight:

[0029] 100 parts of silicone composition

[0030] 0.5 to 0.6 parts coupling agent

[0031] 4 to 6 parts crosslinking agent

[0032] 2 to 3 parts catalyst.

[0033] In one embodiment, the weight ratio of the base material, filler, and tackifier in the silicone composition is 100:15~25:3~5.

[0034] In one embodiment, the weight ratio of γ-aminopropyltriethoxysilane, acetoxytrimethoxysilane, polyether silicone oil and polyoxyethylene phosphate is 5~10:5~8:8~10:5~10.

[0035] In one embodiment, the weight ratio of γ-aminopropyltriethoxysilane, acetoxytrimethoxysilane, polyether silicone oil and polyoxyethylene phosphate is 5~8:5~8:8~10:8~10.

[0036] In one embodiment, the weight ratio of bis[3-(triethoxysilyl)propyl]amine, acetoxyethyltrimethoxysilane, 3-isocyanate-propyltrimethoxysilane and 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane is 20:20~30:20~25:20.

[0037] In one embodiment, the weight ratio of bis[3-(triethoxysilyl)propyl]amine, acetoxyethyltrimethoxysilane, 3-isocyanate-propyltrimethoxysilane and 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane is 20:25~30:20~22:20.

[0038] In one embodiment, the nano-activated calcium carbonate has a particle size of 25 nm to 60 nm and a specific surface area of ​​15 m². 2 / g ~30 m 2 / g. Using this nano-activated calcium carbonate provides the best reinforcing effect and can more effectively improve the overall stability of silicone rubber.

[0039] In one embodiment, the viscosity of the terminal vinyl polydimethylsiloxane is 1000 cps to 100000 cps, and the vinyl content of the terminal vinyl polydimethylsiloxane is 0.08% to 0.15%.

[0040] In one embodiment, the viscosity of the end-vinyl polydimethylsiloxane is 10,000 cps to 50,000 cps.

[0041] In one embodiment, the filler includes one or more of talc, silica powder, titanium dioxide, silica fume, and MQ silicone resin.

[0042] In one embodiment, the silica is fumed silica produced by surface treatment with hexamethyldisilazane.

[0043] In one embodiment, the crosslinking agent includes one or more of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, methyl silicate, tetraethyl orthosilicate, and 1,2-bis(trimethoxysilyl)ethane.

[0044] In one embodiment, the crosslinking agent is methyltrimethoxysilane and tetraethyl orthosilicate in a weight ratio of 0.8 to 1.2:1.

[0045] In one embodiment, the catalyst is a titanate compound or a chelate thereof.

[0046] In one embodiment, the catalyst is one or both of isopropyl titanate and isobutyl titanate.

[0047] In other embodiments of the present invention, a method for preparing dealcohol-type room temperature vulcanizing silicone rubber is disclosed, comprising the following steps:

[0048] (1) The vinyl-terminated polydimethylsiloxane and nano-activated calcium carbonate modified with a surface treatment agent were stirred for 100 min to 140 min at a temperature of 100℃ to 150℃, a vacuum of 0.085 MPa to 0.095 MPa, and a rotation speed of 500 rpm to 800 rpm to obtain the base material;

[0049] (2) When the temperature of the base material drops below 50°C, add the filler and stir for 25 min to 35 min under vacuum of 0.085 MPa to 0.095 MPa and speed of 400 rpm to 500 rpm. Then add the thickener and continue stirring for 50 min to 70 min under vacuum of 0.085 MPa to 0.095 MPa and speed of 250 rpm to 350 rpm to obtain the silicone composition.

[0050] (3) Add crosslinking agent, catalyst and coupling agent to the silica gel composition in sequence, and continue stirring for 50 min to 70 min under vacuum of 0.085 MPa ~ 0.095 MPa and rotation speed of 250 rpm ~ 350 rpm to obtain the product.

[0051] In the following embodiments of the present invention, the nano-activated calcium carbonate with zinc stearate surface treatment used was purchased from Guangxi Huana New Materials Co., Ltd., CCS-30, with a particle size of 25~60 nm and a specific surface area of ​​15 m². 2 / g ~30 m 2 / g.

[0052] The present invention will be described in detail below with reference to specific embodiments.

[0053] Example 1

[0054] This embodiment provides a dealcoholized room temperature vulcanizing silicone rubber, which is prepared by the following method:

[0055] (1) Preparation of base material

[0056] 100 parts of vinyl-terminated polydimethylsiloxane (viscosity of 20000 mPa·s at 25℃, vinyl content of 0.10%) and 110 parts of nano-activated calcium carbonate surface-treated with zinc stearate were added to a dispersing mixer and stirred and dehydrated for 2 h at a temperature of 120℃, a vacuum of -0.085 MPa to 0.095 MPa, and a rotation speed of 600 rpm. After cooling, the base material was obtained.

[0057] (2) Preparation of thickener

[0058] Add 5 parts acetoxytrimethoxysilane, 5 parts γ-aminopropyltriethoxysilane, and 10 parts polyether silicone oil to a beaker, and stir in a constant temperature water bath at 55°C for 60 min. Then add 10 parts polyoxyethylene phosphate and stir for 30 min to obtain a thickener.

[0059] (3) Preparation of silicone composition

[0060] Add 10 parts of fumed silica and 5 parts of MQ silicone resin to 100 parts of the base material prepared in step (1). Stir for 30 min under vacuum of -0.085 MPa to 0.095 MPa and 450 rpm. Then add 3 parts of the tackifier prepared in step (2). Stir for 60 min under the conditions of maintaining a temperature not higher than 50℃, vacuum of -0.085 MPa to 0.095 MPa and 300 rpm to obtain the silicone composition.

[0061] (4) Preparation of coupling agent

[0062] In a reactor equipped with a condenser, 20 parts of bis[3-(triethoxysilyl)propyl]amine, 30 parts of acetoxyethyltrimethoxysilane, 20 parts of 3-isocyanate-propyltrimethoxysilane, and 5 parts of deionized water were added. The mixture was heated to 65°C and stirred for 60 min. The product was then recovered, and 20 parts of 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane were added to the product. The mixture was stirred continuously for 30 min to obtain the coupling agent.

[0063] (5) Preparation of sealant

[0064] In a planetary mixer, under conditions of maintaining a temperature not higher than 50°C, a vacuum degree of -0.085 MPa ~ 0.095 MPa, and a rotation speed of 300 rpm, add 2 parts of a mixed crosslinking agent consisting of methyltrimethoxysilane and 2 parts of tetraethyl orthosilicate, 2 parts of isopropyl titanate, and 0.5 parts of the coupling agent prepared in step (4) to 100 parts of the silica gel composition prepared in step (3). Stir for 60 minutes, discharge and bottle to obtain the final product.

[0065] Example 2

[0066] This embodiment provides a dealcoholized room temperature vulcanizing silicone rubber, which is prepared by the following method:

[0067] (1) Preparation of base material

[0068] 100 parts of vinyl-terminated polydimethylsiloxane (viscosity of 20000 mPa·s at 25℃, vinyl content of 0.10%) and 100 parts of nano-activated calcium carbonate surface-treated with zinc stearate were added to a dispersing mixer and stirred and dehydrated for 2 h at a temperature of 120℃, a vacuum of -0.085 MPa to 0.095 MPa, and a rotation speed of 600 rpm. After cooling, the base material was obtained.

[0069] (2) Preparation of thickener

[0070] Add 8 parts of acetoxytrimethoxysilane, 8 parts of γ-aminopropyltriethoxysilane, and 8 parts of polyether silicone oil to a beaker, and stir in a constant temperature water bath at 55°C for 60 min. Then add 8 parts of polyethylene oxide phosphate and stir for 30 min to obtain a thickener.

[0071] (3) Preparation of silicone composition

[0072] In 100 parts of the base material prepared in step (1), 10 parts of fumed silica and 5 parts of MQ silicone resin were added. The mixture was stirred for 30 min under a vacuum of -0.085 MPa to 0.095 MPa and a rotation speed of 450 rpm. Then, 4 parts of the tackifier prepared in step (2) were added. The mixture was stirred for 60 min under a vacuum of -0.085 MPa to 0.095 MPa and a rotation speed of 300 rpm, at a temperature not exceeding 50°C, to obtain the silicone composition.

[0073] (4) Preparation of coupling agent

[0074] In a reactor equipped with a condenser, 20 parts of bis[3-(triethoxysilyl)propyl]amine, 30 parts of acetoxyethyltrimethoxysilane, 20 parts of 3-isocyanate-propyltrimethoxysilane, and 5 parts of deionized water were added. The mixture was heated to 65°C and stirred for 60 min. The product was then recovered, and 20 parts of 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane were added to the product. The mixture was stirred continuously for 30 min to obtain the coupling agent.

[0075] (5) Preparation of sealant

[0076] In a planetary mixer, under conditions of maintaining a temperature not higher than 50°C, a vacuum degree of -0.085 MPa ~ 0.095 MPa, and a rotation speed of 300 rpm, add 2 parts of a mixed crosslinking agent consisting of methyltrimethoxysilane and 2 parts of tetraethyl orthosilicate, 2 parts of isopropyl titanate, and 0.5 parts of the coupling agent prepared in step (4) to 100 parts of the silica gel composition prepared in step (3). Stir for 60 minutes, discharge and bottle to obtain the final product.

[0077] Example 3

[0078] This embodiment provides a dealcoholized room temperature vulcanizing silicone rubber, which is prepared by the following method:

[0079] (1) Preparation of base material

[0080] 100 parts of vinyl-terminated polydimethylsiloxane (viscosity of 20000 mPa·s at 25℃, vinyl content of 0.10%) and 100 parts of nano-activated calcium carbonate surface-treated with zinc stearate were added to a dispersing mixer and stirred and dehydrated for 2 h at a temperature of 120℃, a vacuum of -0.085 MPa to 0.095 MPa, and a rotation speed of 600 rpm. After cooling, the base material was obtained.

[0081] (2) Preparation of thickener

[0082] Add 10 parts of acetoxytrimethoxysilane, 8 parts of γ-aminopropyltriethoxysilane, and 10 parts of polyether silicone oil to a beaker, and stir in a constant temperature water bath at 55°C for 60 min. Then add 6 parts of polyethylene oxide phosphate and stir for 30 min to obtain a thickener.

[0083] (3) Preparation of silicone composition

[0084] Add 15 parts of fumed silica and 10 parts of MQ silicone resin to 100 parts of the base material prepared in step (1). Stir for 30 min under vacuum of -0.085 MPa to 0.095 MPa and 450 rpm. Then add 4 parts of the tackifier prepared in step (2). Stir for 60 min under the conditions of maintaining a temperature not higher than 50℃, vacuum of -0.085 MPa to 0.095 MPa and 300 rpm to obtain the silicone composition.

[0085] (4) Preparation of coupling agent

[0086] In a reactor equipped with a condenser, 20 parts of bis[3-(triethoxysilyl)propyl]amine, 20 parts of acetoxyethyltrimethoxysilane, 25 parts of 3-isocyanate-propyltrimethoxysilane, and 5 parts of deionized water were added. The mixture was heated to 65°C and stirred for 60 min. The product was then recovered, and 20 parts of 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane were added to the product. The mixture was stirred continuously for 30 min to obtain the coupling agent.

[0087] (5) Preparation of sealant

[0088] In a planetary mixer, under conditions of maintaining a temperature not higher than 50°C, a vacuum degree of -0.085 MPa ~ 0.095 MPa, and a rotation speed of 300 rpm, add 2 parts of a mixed crosslinking agent consisting of methyltrimethoxysilane and 2 parts of tetraethyl orthosilicate, 2 parts of isopropyl titanate, and 0.6 parts of the coupling agent prepared in step (4) to 100 parts of the silica gel composition prepared in step (3). Stir for 60 minutes, discharge and bottle to obtain the final product.

[0089] Example 4

[0090] This embodiment provides a dealcoholized room temperature vulcanizing silicone rubber, which is prepared by the following method:

[0091] (1) Preparation of base material

[0092] 100 parts of vinyl-terminated polydimethylsiloxane (viscosity of 20000 mPa·s at 25℃, vinyl content of 0.10%) and 80 parts of nano-activated calcium carbonate surface-treated with zinc stearate were added to a dispersing mixer and stirred and dehydrated for 2 h at a temperature of 120℃, a vacuum of -0.085 MPa to 0.095 MPa, and a rotation speed of 600 rpm. After cooling, the base material was obtained.

[0093] (2) Preparation of thickener

[0094] Add 5 parts acetoxytrimethoxysilane, 8 parts γ-aminopropyltriethoxysilane, and 10 parts polyether silicone oil to a beaker, and stir in a constant temperature water bath at 55°C for 60 min. Then add 5 parts polyoxyethylene phosphate and stir for 30 min to obtain a thickener.

[0095] (3) Preparation of silicone composition

[0096] Add 15 parts of fumed silica and 10 parts of MQ silicone resin to 100 parts of the base material prepared in step (1). Stir for 30 min under vacuum of -0.085 MPa to 0.095 MPa and a rotation speed of 450 rpm. Then add 5 parts of the tackifier prepared in step (2). Stir for 60 min under the conditions of maintaining a temperature not higher than 50℃, vacuum of -0.085 MPa to 0.095 MPa and a rotation speed of 300 rpm to obtain the silicone composition.

[0097] (4) Preparation of coupling agent

[0098] In a reactor equipped with a condenser, 20 parts of bis[3-(triethoxysilyl)propyl]amine, 30 parts of acetoxyethyltrimethoxysilane, 20 parts of 3-isocyanate-propyltrimethoxysilane, and 5 parts of deionized water were added. The mixture was heated to 65°C and stirred for 60 min. The product was then recovered, and 20 parts of 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane were added to the product. The mixture was stirred continuously for 30 min to obtain the coupling agent.

[0099] (5) Preparation of sealant

[0100] In a planetary mixer, under conditions of maintaining a temperature not higher than 50°C, a vacuum degree of -0.085 MPa ~ 0.095 MPa, and a rotation speed of 300 rpm, add 2 parts of a mixed crosslinking agent consisting of methyltrimethoxysilane and 2 parts of tetraethyl orthosilicate, 2.5 parts of isopropyl titanate, and 0.6 parts of the coupling agent prepared in step (4) to 100 parts of the silica gel composition prepared in step (3). Stir for 60 min, discharge and bottle to obtain the final product.

[0101] Comparative Example 1

[0102] This comparative example provides a dealcoholized room temperature vulcanizing silicone rubber, which is prepared by the following method:

[0103] (1) Preparation of base material

[0104] Same as Example 1.

[0105] (2) Preparation of silicone composition

[0106] In 100 parts of the base material prepared in step (1), 10 parts of fumed silica and 5 parts of MQ silicone resin were added. The mixture was stirred for 30 min under a vacuum of -0.085 MPa to 0.095 MPa and a rotation speed of 450 rpm. Then, 0.5 parts of acetoxytrimethoxysilane, 0.5 parts of γ-aminopropyltriethoxysilane, 1 part of polyether silicone oil and 1 part of polyoxyethylene phosphate were added. The mixture was stirred for 60 min under a vacuum of -0.085 MPa to 0.095 MPa and a rotation speed of 300 rpm, with the temperature not exceeding 50°C, to obtain the silicone composition.

[0107] (3) Preparation of coupling agent

[0108] Same as Example 1.

[0109] (4) Preparation of sealant

[0110] Same as Example 1.

[0111] Comparative Example 2

[0112] This comparative example provides a dealcoholized room temperature vulcanizing silicone rubber, which is prepared by the following method:

[0113] (1) Preparation of base material

[0114] 100 parts of methoxy-terminated polydimethylsiloxane (viscosity of 20000 mPa·s at 25℃, methoxy content of 0.50%) and 110 parts of nano-activated calcium carbonate surface-treated with zinc stearate were added to a dispersing mixer and stirred and dehydrated for 2 h at a temperature of 120℃, a vacuum of -0.085 MPa to 0.095 MPa, and a rotation speed of 600 rpm. After cooling, the base material was obtained.

[0115] (2) Preparation of thickener

[0116] Same as Example 1.

[0117] (3) Preparation of silicone composition

[0118] Same as Example 1.

[0119] (4) Preparation of coupling agent

[0120] Same as Example 1.

[0121] (5) Preparation of sealant

[0122] Same as Example 1.

[0123] Comparative Example 3

[0124] This comparative example provides a dealcoholized room temperature vulcanizing silicone rubber, which is prepared by the following method:

[0125] (1) Preparation of base material

[0126] Same as Example 1.

[0127] (2) Preparation of thickener

[0128] Same as Example 1.

[0129] (3) Preparation of silicone composition

[0130] Same as Example 1.

[0131] (4) Preparation of sealant

[0132] In a planetary mixer, under conditions of maintaining a temperature not exceeding 50°C, a vacuum of -0.085 MPa to 0.095 MPa, and a rotation speed of 300 rpm, add 2 parts of a mixed crosslinking agent consisting of methyltrimethoxysilane and 2 parts of tetraethyl orthosilicate, 2 parts of isopropyl titanate, and 0.5 parts of a coupling agent (including 0.1 parts of bis[3-(triethoxysilyl)propyl]amine, 0.2 parts of acetoxyethyltrimethoxysilane, 0.1 parts of 3-isocyanate-propyltrimethoxysilane, and 0.1 parts of 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane) to 100 parts of the silica gel composition prepared in step (3). Stir for 60 min, discharge and bottle to obtain the final product.

[0133] Comparative Example 4

[0134] This comparative example provides a dealcoholized room temperature vulcanizing silicone rubber, which is prepared by the following method:

[0135] (1) Preparation of base material

[0136] Same as Example 1.

[0137] (2) Preparation of coupling agent

[0138] Same as Example 1.

[0139] (3) Preparation of sealant

[0140] In a planetary mixer, 10 parts of fumed silica and 5 parts of MQ silicone resin were added to 100 parts of the base material prepared in step (1). The mixture was stirred for 30 min under vacuum conditions of -0.085 MPa ~ 0.095 MPa and a speed of 450 rpm. Then, 0.5 parts of acetoxytrimethoxysilane, 0.5 parts of γ-aminopropyltriethoxysilane, 1 part of polyether silicone oil, and 1 part of polyoxyethylene phosphate were added. The mixture was stirred for 60 min under conditions of temperature not exceeding 50℃, vacuum conditions of -0.085 MPa ~ 0.095 MPa, and a speed of 300 rpm. Then, a mixed crosslinking agent consisting of 2 parts of methyltrimethoxysilane and 2 parts of tetraethyl orthosilicate, 2 parts of isopropyl titanate, and 0.5 parts of the coupling agent prepared in step (2) were added. The mixture was stirred for 60 min, and the product was discharged and bottled to obtain the final product.

[0141] The following performance tests were performed on the dealcoholized room temperature vulcanizing silicone rubbers prepared in Examples 1-4 and Comparative Examples 1-4:

[0142] (1) Surface drying time: Tested according to GB / T 13477-2002

[0143] (2) Consistency: Tested according to GB / T 1749-1979

[0144] (3) Curing depth: Tested according to Method II of GB / T32369-2015, wedge groove method.

[0145] (4) Tensile strength and elongation at break: tested according to GB / T528-2009

[0146] The test results are shown in Table 1.

[0147] Table 1

[0148]

[0149] As shown in Table 1, the 24-hour curing depth of the de-alcoholized room temperature vulcanizing silicone rubbers prepared in Examples 1-4 of this invention is all >4.0 mm, and the tensile strength is all >4.0 MPa, which is much higher than the deep curing performance and mechanical strength of ordinary de-alcoholized room temperature vulcanizing silicone rubbers. At the same time, they also have a good curing rate, which can meet the requirements for normal use.

[0150] Compared to Example 1, Comparative Example 1 did not pre-prepare a tackifier; instead, the tackifier components were directly added to the system. This resulted in a decreased curing rate, significantly reduced curing depth, and a marked decrease in the mechanical strength after curing. Comparative Example 2 used methoxy-terminated polydimethylsiloxane as its base material, leading to a rapid decrease in the curing depth of the sealant and a significant reduction in the mechanical strength after curing. Comparative Example 3 did not pre-prepare a coupling agent; instead, the coupling agent components were directly added to the system. This significantly affected the curing rate, curing depth, tensile strength, and elongation at break. Comparative Example 4 did not pre-prepare a tackifier or a silicone composition; instead, these components were directly added to the system. The resulting dealcoholized room temperature vulcanizing silicone rubber exhibited significantly reduced curing rate, 24-hour curing depth, tensile strength, and elongation at break.

[0151] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0152] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A dealcohol-type room temperature vulcanizing silicone rubber, characterized in that, It is prepared from the following raw materials in parts by weight: 100 parts of silicone composition 0.2 to 1 part coupling agent 4 to 10 parts of crosslinking agent 2 to 8 parts catalyst The silicone composition is prepared from 100 parts of base material, 15 to 25 parts of filler, and 1 to 6 parts of tackifier. The base material is prepared from 100 parts of vinyl-terminated polydimethylsiloxane and 80 to 110 parts of nano-active calcium carbonate modified with a surface treatment agent; The thickener is prepared by the following method: γ-aminopropyltriethoxysilane, acetoxytrimethoxysilane and polyether silicone oil are stirred in a water bath at 50℃~60℃ for 55 min~65 min, and then polyoxyethylene phosphate is added and stirred for 25 min~35 min. The coupling agent is prepared by the following method: bis[3-(triethoxysilyl)propyl]amine, acetoxyethyltrimethoxysilane, 3-isocyanate-propyltrimethoxysilane and water are heated to 60℃~70℃ and stirred for 55 min~65 min, and the product is recovered. Then, 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane is added to the product and stirred for 25 min~35 min.

2. The dealcohol-type room temperature vulcanizing silicone rubber according to claim 1, characterized in that, It is prepared from the following raw materials in parts by weight: 100 parts of silicone composition 0.5 to 0.6 parts of coupling agent 4 to 6 parts crosslinking agent 2 to 3 parts catalyst.

3. The dealcohol-type room temperature vulcanizing silicone rubber according to claim 1, characterized in that, In the silicone composition, the weight ratio of the base material, filler and tackifier is 100:15~25:3~5.

4. The dealcohol-type room temperature vulcanizing silicone rubber according to claim 1, characterized in that, The weight ratio of γ-aminopropyltriethoxysilane, acetoxytrimethoxysilane, polyether silicone oil and polyoxyethylene phosphate is 5~10:5~8:8~10:5~10, preferably 5~8:5~8:8~10:8~10.

5. The dealcohol-type room temperature vulcanizing silicone rubber according to claim 1, characterized in that, The weight ratio of bis[3-(triethoxysilyl)propyl]amine, acetoxyethyltrimethoxysilane, 3-isocyanate-propyltrimethoxysilane and 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane is 20:20~30:20~25:20, preferably 20:25~30:20~22:

20.

6. The dealcoholized room temperature vulcanizing silicone rubber according to any one of claims 1 to 5, characterized in that, The viscosity of the terminal vinyl polydimethylsiloxane is 1000 cps to 100000 cps, preferably 10000 cps to 50000 cps, and the vinyl content of the terminal vinyl polydimethylsiloxane is 0.08% to 0.15%. And / or, the nano-activated calcium carbonate has a particle size of 25 nm to 60 nm and a specific surface area of ​​15 m². 2 / g ~30 m 2 / g.

7. The dealcohol-type room temperature vulcanizing silicone rubber according to any one of claims 1 to 5, characterized in that, The filler includes one or more of talc, silica powder, titanium dioxide, silica, and MQ silicone resin; preferably, the silica is fumed silica that has been surface-treated with hexamethyldisilazane.

8. The dealcohol-type room temperature vulcanizing silicone rubber according to any one of claims 1 to 5, characterized in that, The crosslinking agent includes one or more of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, methyl silicate, tetraethyl orthosilicate, and 1,2-bis(trimethoxysilyl)ethane. Preferably, the crosslinking agent is methyltrimethoxysilane and tetraethyl orthosilicate in a weight ratio of 0.8 to 1.2:

1.

9. The dealcohol-type room temperature vulcanizing silicone rubber according to any one of claims 1 to 5, characterized in that, The catalyst is a titanate compound or its chelate, preferably one or two of isopropyl titanate and isobutyl titanate.

10. A method for preparing a dealcohol-type room temperature vulcanizing silicone rubber according to any one of claims 1 to 9, characterized in that, Includes the following steps: (1) The vinyl-terminated polydimethylsiloxane and nano-activated calcium carbonate modified with a surface treatment agent were stirred for 100 min to 140 min at a temperature of 100℃ to 150℃, a vacuum of 0.085 MPa to 0.095 MPa, and a rotation speed of 500 rpm to 800 rpm to obtain the base material; (2) When the temperature of the base material drops below 50°C, add the filler and stir for 25 min to 35 min under vacuum of 0.085 MPa to 0.095 MPa and speed of 400 rpm to 500 rpm. Then add the thickener and continue stirring for 50 min to 70 min under vacuum of 0.085 MPa to 0.095 MPa and speed of 250 rpm to 350 rpm to obtain the silicone composition. (3) Add crosslinking agent, catalyst and coupling agent to the silica gel composition in sequence, and continue stirring for 50 min to 70 min under vacuum of 0.085 MPa ~ 0.095 MPa and rotation speed of 250 rpm ~ 350 rpm to obtain the product.

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