Two-component inert gas room temperature foaming sealing silica gel and preparation method thereof

Abstract

The present invention discloses a two-component inert gas room-temperature foaming sealing silicone and a preparation method thereof. The foaming sealing silicone comprises two components, A and B. Component A comprises a modified silicone oil 1, a modified silicone oil 2, white carbon black, a flame retardant, and a tin catalyst mixed in a weight ratio of 20-50:10-30:0.1-5:20-50:0.01-0.5; and component B comprises a hydroxy silicone oil, water, white carbon black, carbon black, and a flame retardant mixed in a weight ratio of 30-70:0.1-5:0.1-5:0.1-5:20-50. In the two modified silicone oils used in the present invention, the NCO activity is reduced, thereby reducing its reactivity with water, resulting in a longer operating time for the foaming silicone, making it more suitable for practical production applications.

Description

Technical Field

[0001] The invention relates to a two-component inert gas room temperature foaming sealing silica gel and a preparation method thereof, belonging to the technical field of organosilicon modification. Background Art

[0002] Silicone foam is a new type of organic material with high resilience and low density. It boasts excellent properties such as high and low temperature resistance, low compression set, and mechanical fatigue resistance, as well as environmental friendliness, odorlessness, waterproofness, fire resistance, and surface properties. It is widely used in many industrial and daily necessities. Silicone foam boasts a wide range of applications, enabling customized product solutions tailored to customer needs in areas such as new energy vehicles and electrical pipes. Silicone foam can be used for shock absorption, sealing, cushioning, and noise reduction in high-speed rail and automobile applications, as well as for indoor and outdoor waterproofing and flame retardancy, small household electrical wiring, and various products requiring thermal insulation, sound insulation, and anti-static properties. Waterproof silicone rubber foam gaskets are also widely used in many household appliances, such as rice cookers, water dispensers, and ovens. Due to their high sealing requirements, they can be used as sealing components. Due to their long service life, waterproof silicone rubber foam gaskets can ensure the sealing of electrical equipment for a long time.

[0003] However, most of the foam sealing silicones on the market require molds to be designed in advance to make the foam sealing silicone into a specified shape, which is very troublesome to use for special component structures. Summary of the Invention

[0004] The present invention addresses the shortcomings of the prior art by providing a two-component inert gas room-temperature foaming silicone sealant and a method for preparing the same. The two modified silicone oils used in this sealant have -NCO group reactivity that is lower than that of ordinary small-molecule monomers, providing ample operating time after mixing components A and B.

[0005] In order to achieve the above objectives, the technical solutions adopted are:

[0006] One of the purposes of the present invention is to provide a two-component inert gas room temperature foaming sealing silica gel, which consists of two components A and B, wherein component A is composed of modified silicone oil 1, modified silicone oil 2, white carbon black, a flame retardant, and a tin catalyst mixed in a weight ratio of 20-50:10-30:0.1-5:20-50:0.01-0.5; component B is composed of hydroxy silicone oil, water, white carbon black, carbon black, and a flame retardant mixed in a weight ratio of 30-70:0.1-5:0.1-5:0.1-5:20-50, and component A:component B are mixed in a mass ratio of 1:1;

[0007] Wherein, the structure of the modified silicone oil 1 is:

[0008] OCN-B-NHCHOO-CH2-CH2-OOCNH-B-NCO

[0009]

[0010] The structure of the modified silicone oil 2 is:

[0011]

[0012] Furthermore, the white carbon black has a specific surface area of ​​145 to 210 m 2 / g of hydrophobic white carbon black; the carbon black specific surface area is 50 to 300m 2 / g.

[0013] Furthermore, the flame retardant is one or more of a halogen flame retardant, a phosphorus flame retardant, aluminum hydroxide, and magnesium hydroxide.

[0014] Furthermore, the water is deionized water; and the tin catalyst is one or more of dibutyltin dilaurate, stannous octoate, dibutyltin didodecylsulfide, dibutyltin diacetate, and dibutyltin dilaurate.

[0015] The second object of the present invention is to provide a method for preparing the above-mentioned two-component inert gas room temperature foaming sealing silica gel. The preparation method of the modified silicone oil 1 is as follows: add an isocyanate monomer containing two NCO groups and a tin catalyst with an isocyanate monomer amount of 5 to 18 ppm to a three-necked flask, stir at 50 to 90° C. for 5 to 10 minutes, slowly add hydroxy silicone oil dropwise to the system, the molar ratio of -OH to NCO group is 1:2, react for 1 to 2 hours after the addition is completed, and obtain monomer 1. Then, slowly add a certain amount of ethylene glycol dropwise to the system, the molar ratio of alcohol OH group to NCO group is 1:2, and react at room temperature for 1 to 2 hours to obtain modified silicone oil 1. The molecular formula of the hydroxy silicone oil is (HOMe2SiO 0.5 )2(Me2SiO) m , m=8-200; the isocyanate monomer containing two NCO groups is one of hexamethylene diisocyanate, diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and isophorone diisocyanate. The reaction formula is:

[0016]

[0017] Furthermore, the preparation method of the modified silicone oil 2 is as follows:

[0018] 3-Isocyanatepropyltrimethoxysilane and 5-18 ppm of a tin catalyst were added to a three-necked flask, and the mixture was stirred at room temperature for 0.5-1 h to obtain a mixture 1; ethylene glycol was added to the three-necked flask, and the mixture 1 was slowly added dropwise to the flask. After the addition was complete, the mixture was reacted at room temperature for 1-2 h; then monomer 1 was added to the system with a molar ratio of alcohol OH group to NCO group of 1:2, and the mixture was reacted at room temperature for 1-2 h to obtain a modified silicone oil 2.

[0019] The reaction formula is:

[0020]

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] Modified silicone oil 1, used in the sealant prepared in this invention, incorporates an -NCO group. This reacts with water under a tin catalyst to produce carbon dioxide, providing an inert gas for the foaming silicone. Modified silicone oil 2, while incorporating an -NCO group at one end to provide the inert gas for foaming, also incorporates a siloxy group at the other end. This reacts with the hydroxyl silicone oil under a tin catalyst to provide a crosslinking group. The -NCO group reactivity of both silicone oils is lower than that of conventional small-molecule monomers, providing ample time for mixing components A and B, making them more suitable for practical production applications. DETAILED DESCRIPTION

[0023] 42g of hexamethylene diisocyanate and 8ppm of tin catalyst (dibutyltin dilaurate) were added to a 500mL three-necked flask and stirred at 60°C for 5-10min. 0.5 )2(Me2SiO) m , m=20, 195.4g of hydroxy silicone oil, after complete addition, react for 1-2h to obtain monomer 1, then slowly add 3.875g of ethylene glycol dropwise to the system, react at room temperature for 1-2h to obtain modified silicone oil 1.

[0024] 250 g of 3-isocyanatepropyltrimethoxysilane and 8 ppm of a tin catalyst were added to a 500 mL three-necked flask, and the mixture was stirred at room temperature for 0.5 to 1 h to obtain a mixture 1.

[0025] Add 7.75g of ethylene glycol to a three-necked flask, then slowly dropwise add 25.625g of mixture 1. After the addition is complete, allow to react at room temperature for 1-2 hours. Then, add 237g of monomer 1 and allow to react at room temperature for 1-2 hours to obtain modified silicone oil 2.

[0026] Example 1

[0027] Component A consists of modified silicone oil 1, modified silicone oil 2, white carbon black (specific surface area of ​​145 to 210 m 2 / g hydrophobic white carbon black), flame retardant (aluminum hydroxide), tin catalyst (dibutyltin dilaurate) are mixed in a weight ratio of 50:10:0.5:30:0.05; component B is composed of hydroxy silicone oil ((HOMe2SiO 0.5 )2(Me2SiO) m ,m=100), deionized water, white carbon black (specific surface area of ​​145~210m 2 / g hydrophobic white carbon black), carbon black (specific surface area of ​​50 to 300m 2 / g;) and flame retardant (aluminum hydroxide) were mixed in a weight ratio of 60:0.5:0.5:0.1:30. Components A and B were mixed in a mass ratio of 1:1 to obtain sealing silica gel. The test results are shown in Table 1.

[0028] Example 2

[0029] Component A consists of modified silicone oil 1, modified silicone oil 2, white carbon black (specific surface area of ​​145 to 210 m 2 / g hydrophobic white carbon black), flame retardant (aluminum hydroxide), tin catalyst (dibutyltin dilaurate) are mixed in a weight ratio of 40:20:0.5:30:0.05; component B is composed of hydroxy silicone oil ((HOMe2SiO 0.5 )2(Me2SiO) m ,m=100), deionized water, white carbon black (specific surface area of ​​145~210m 2 / g hydrophobic white carbon black), carbon black (specific surface area of ​​50 to 300m 2 / g;) and flame retardant (aluminum hydroxide) were mixed in a weight ratio of 60:0.5:0.5:0.1:30. Components A and B were mixed in a mass ratio of 1:1 to obtain sealing silica gel. The test results are shown in Table 1.

[0030] Example 3

[0031] Component A consists of modified silicone oil 1, modified silicone oil 2, white carbon black (specific surface area of ​​145 to 210 m 2 / g hydrophobic white carbon black), flame retardant (aluminum hydroxide), tin catalyst (dibutyltin dilaurate) are mixed in a weight ratio of 30:30:0.5:30:0.05; component B is composed of hydroxy silicone oil ((HOMe2SiO 0.5 )2(Me2SiO) m ,m=100), deionized water, white carbon black (specific surface area of ​​145~210m 2 / g hydrophobic white carbon black), carbon black (specific surface area of ​​50 to 300m 2 / g;) and flame retardant (aluminum hydroxide) were mixed in a weight ratio of 60:0.5:0.5:0.1:30. Components A and B were mixed in a mass ratio of 1:1 to obtain sealing silica gel. The test results are shown in Table 1.

[0032] Comparative Example 1

[0033] Component A is composed of methyl silicone oil, white carbon black (specific surface area of ​​145 to 210 m 2 / g hydrophobic white carbon black), flame retardant (aluminum hydroxide), tin catalyst (dibutyltin dilaurate) are mixed in a weight ratio of 60:0.5:30:0.05; component B is composed of hydroxy silicone oil ((HOMe2SiO 0.5 )2(Me2SiO) m ,m=100), deionized water, white carbon black (specific surface area of ​​145~210m 2 / g hydrophobic white carbon black), carbon black (specific surface area of ​​50 to 300m 2 / g;) and flame retardant (aluminum hydroxide) were mixed in a weight ratio of 60:0.5:0.5:0.1:30. Components A and B were mixed in a mass ratio of 1:1 to obtain sealing silica gel. The test results are shown in Table 1.

[0034] Table 1. Test results of sealing silica gel performance of Examples 1 to 3 and Comparative Example 1

[0035] performance Example 1 Example 2 Example 3 Comparative Example 1 Appearance after curing black black black black Hardness / Shore O 32 35 39 16 <![CDATA[Density (g / cm 3 )]]> 0.66 0.69 0.73 1.2 Porosity uniformity Uniform Uniform Uniform No bubbles

[0036] As shown in Table 1, the conventional silicone oil in Comparative Example 1 is unable to generate gas for foaming. Comparing Examples 1, 2, and 3, it is clear that modified silicone oil 1 primarily provides the foaming gas, while modified silicone oil 2, in addition to providing a small amount of foaming gas, also provides crosslinking. Therefore, the ratio of the two silicone oils can be adjusted appropriately based on the density and hardness requirements.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the concept and principle of the present invention are included in the scope of protection of the present invention.

Claims

1. A two-component inert gas room temperature foaming sealing silica gel, characterized in that: The foam sealing silicone consists of two components, A and B, wherein component A is composed of modified silicone oil 1, modified silicone oil 2, white carbon black, flame retardant, and tin catalyst in a weight ratio of 20-50:10-30:0.1-5:20-50:0.01-0.5; component B is composed of hydroxy silicone oil, water, white carbon black, carbon black, and flame retardant in a weight ratio of 30-70: Mix in a weight ratio of 0.1-5:0.1-5:0.1-5:20-50, and component A: component B in a mass ratio of 1:1; Wherein, the structure of the modified silicone oil 1 is: OCN-B-NHCOO-CH2-CH2-OOCNH-B-NCO B: The structure of the modified silicone oil 2 is:

2. The two-component inert gas room temperature foaming sealing silica gel according to claim 1, characterized in that: The white carbon black has a specific surface area of ​​145 to 210 m 2 / g of hydrophobic white carbon black; the carbon black specific surface area is 50 to 300m 2 / g.

3. The two-component inert gas room temperature foaming sealing silica gel according to claim 1, characterized in that: The flame retardant is one or more of a halogen flame retardant, a phosphorus flame retardant, aluminum hydroxide, and magnesium hydroxide.

4. The two-component inert gas room temperature foaming sealing silica gel according to claim 1, characterized in that: The water is deionized water; the tin catalyst is one or more of stannous octoate, dibutyltin didodecylsulfide, dibutyltin diacetate, and dibutyltin dilaurate.

5. The two-component inert gas room temperature foaming sealing silica gel according to claim 1, characterized in that: The preparation method of the modified silicone oil 1 is as follows: an isocyanate monomer containing two NCO groups and a tin catalyst having an isocyanate monomer amount of 5 to 18 ppm are added to a three-necked flask, and the mixture is stirred at 50 to 90° C. for 5 to 10 minutes. Hydroxyl silicone oil is slowly added dropwise to the system, with a molar ratio of OH to NCO groups of 1:

2. After the addition is complete, the mixture is reacted for 1 to 2 hours to obtain monomer 1. A certain amount of ethylene glycol is then slowly added dropwise to the system, with a molar ratio of OH to NCO groups of 1:

2. The mixture is reacted at room temperature for 1 to 2 hours to obtain modified silicone oil 1. The molecular formula of the hydroxyl silicone oil is (HOMe2SiO 0.5 )2(Me2SiO) m , m=8-200; the isocyanate monomer containing two NCO groups is one of hexamethylene diisocyanate, diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and isophorone diisocyanate.

6. The two-component inert gas room temperature foaming sealing silica gel according to claim 1, characterized in that: The preparation method of the modified silicone oil 2 is as follows: 3-Isocyanatepropyltrimethoxysilane and 5-18 ppm of a tin catalyst were added to a three-necked flask, and the mixture was stirred at room temperature for 0.5-1 h to obtain a mixture 1. Ethylene glycol was added to the three-necked flask, and the mixture 1 was slowly added dropwise to the flask. After the addition was complete, the mixture was reacted at room temperature for 1-2 h. Then, monomer 1 was added to the system with a molar ratio of OH group to NCO group of 1:2, and the mixture was reacted at room temperature for 1-2 h to obtain a modified silicone oil 2.

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