A rigid foamed silicone material and method of manufacture

Abstract

The application discloses a hard foamed organic silicon material and a preparation method, and relates to the technical field of foamed organic silicon materials. The hard foamed organic silicon material is prepared from the following components in parts by mass: 80-100 parts of vinyl silicon oil, 5-20 parts of hydrogen-containing silicon oil, 15-25 parts of hydroxyl silicon oil, 0.1-2 parts of a platinum gold catalyst, 3-15 parts of a foaming agent, 2-5 parts of a flame retardant, and 10-30 parts of a reinforcing filler. The novel flame retardant formula and the optimized foaming process are used, so that the material can effectively form a protective carbon layer and release inert gas when burning, thereby inhibiting the spread of combustion, reducing the generation of smoke, greatly improving the fire safety of the material, and improving the mechanical properties of the material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foamed silicone materials, and particularly relates to a hard foamed silicone material and a preparation method thereof. BACKGROUND

[0002] As a new emerging technology of silicone materials, hard foamed silicone materials have been increasingly demanded in the fields of building insulation, electronic and electrical packaging, aerospace, etc. in recent years. However, the hard foamed silicone materials in the prior art still have many problems and need to be further optimized and improved.

[0003] Traditional hard foamed silicone materials have obvious deficiencies in flame retardant performance. Due to their flammable characteristics, the materials can easily burn rapidly and release toxic gases under high temperature environments, which not only poses a serious threat to personnel safety, but also greatly limits the application of the materials in scenarios with high requirements for fireproof performance, such as building external wall insulation systems and protection of internal components of electronic devices. This problem is particularly prominent in complex environments and high safety requirement scenarios. Secondly, the foaming performance and processing technology of the materials need to be improved. In the prior art, the foaming process is often accompanied by problems of non-uniformity of the foam structure and poor dimensional stability. This not only affects the final performance of the materials, but also increases the difficulty of subsequent processing and application. Furthermore, the mechanical strength and heat resistance of the materials are difficult to balance. Traditional hard foamed silicone materials often sacrifice the mechanical strength and heat resistance of the materials while pursuing low density and high foaming ratio. This makes the materials prone to deformation, cracking, etc. in actual application, especially under long-term load bearing or exposure to high temperature environments.

[0004] Therefore, it is urgent to develop a new type of hard foamed silicone material and a preparation method thereof, which optimizes the material formula and process to provide a hard foamed silicone material with excellent flame retardant performance, good mechanical strength and heat resistance, so as to better meet the demand of modern industry and building field for high-performance materials. SUMMARY

[0005] The present application aims to solve the problems of insufficient flame retardant performance, difficulty in balancing the mechanical strength and heat resistance of the materials, etc. in the prior art, and provides a hard foamed silicone material and a preparation method thereof, which aims to improve the hardness and mechanical strength of the materials, enhance the flame retardant performance, and meet the demand of modern industry for high-performance non-metallic additive materials.

[0006] To achieve the above object, the technical scheme adopted by the present application is: a rigid foamed organic silicon material, which is prepared from the following components by mass: vinyl silicone oil: 80-100 parts, hydrogen-containing silicone oil: 5-20 parts, hydroxyl silicone oil: 15-25 parts, platinum catalyst: 0.1-2 parts, foaming agent: 3-15 parts, flame retardant: 2-5 parts, and reinforcing filler: 10-30 parts.

[0007] The flame retardant is a compound shown in formula 1:

[0008] Formula 1: ;

[0009] In formula 1, R1 is a substituent group, and R1 is selected from: methyl, ethyl, amino, and cyano.

[0010] Further, the vinyl content of the vinyl silicone oil is 0.1%-6%, and the viscosity is 500-10000 mPa·s.

[0011] Further, the hydrogen content of the hydrogen-containing silicone oil is 0.5%-1.5%, and the viscosity is 100-500 mPa·s.

[0012] Further, the hydroxyl content of the hydroxyl silicone oil is 0.4%-7%.

[0013] Further, the platinum catalyst is at least one of a Karstedt catalyst, a diethylenedimethyltetrasiloxane platinum complex, and a chloroplatinic acid diethyl phthalate complex.

[0014] Further, the foaming agent is at least one of 4,4'-oxobenzene sulfonyl hydrazine or azodicarbonamide.

[0015] Further, the reinforcing filler is at least one of white carbon black, precipitated white carbon black, calcium carbonate, and quartz powder.

[0016] Further, the flame retardant is selected from any one of the compounds shown in the following structures:

[0017] ;

[0018] .

[0019] A preparation method of a rigid foamed organic silicon material, comprising the following steps:

[0020] S1. The vinyl silicone oil, flame retardant, foaming agent, and reinforcing filler are added to a planetary mixer, and stirred at room temperature for 1 hour to obtain a premix, which is evenly divided into an A component premix and a B component premix;

[0021] S2. The hydrogen-containing silicone oil is added to the A component premix, and stirred evenly to obtain an A component mixture;

[0022] S3. Adding the hydroxyl silicone oil and platinum gold catalyst into the B component premix, stirring until uniform, to obtain a B component mixture;

[0023] S4. Mixing the A component mixture and the B component mixture until uniform, low temperature foaming at 55-65℃, then warming up and foaming, and finally vulcanizing at 130℃, to obtain a rigid foamed silicone material.

[0024] Further, the warming up and foaming in step S4 is divided into three gradients, with temperatures of 70-80℃, 100-110℃, and 130-140℃, respectively.

[0025] When the material burns, the flame retardant will rapidly decompose upon heating, generating inert gases such as ammonia, nitrogen, and water vapor, which are non-combustible gases. These non-combustible gases can effectively dilute the concentration of oxygen and combustible gases (such as hydrocarbons) in the combustion area, making it difficult for the combustion reaction to continue. The decomposition of the flame retardant is a strong endothermic process that will absorb a large amount of heat generated by combustion, thereby reducing the temperature of the material surface and slowing down or even interrupting the thermal decomposition process. In addition, the flame retardant can promote the formation of a dense and stable expanded carbon layer on the burning surface of the polymer material. This carbon layer acts like a strong barrier, effectively blocking the transfer of external heat to the internal polymer, preventing the deep-layer material from continuing to decompose, blocking the escape of internal combustible gases, and at the same time preventing external oxygen from entering, thereby suffocating the flame. Solid-phase carbonization reduces the generation of flammable volatile substances, thereby also reducing the smoke emission. The flame retardant also generates strong dehydrating acids such as phosphoric acid when it decomposes upon heating. These strong acids will catalyze the dehydration crosslinking reaction of the polymer matrix and the carbon source usually added, converting the hydrocarbons in the polymer into non-volatile carbon-rich residual carbon, participating in the formation of a complex crosslinked structure, and helping to enhance the strength and stability of the final carbon layer.

[0026] The rigid foamed silicone material of the present application achieves synergistic effect through chemical cross-linking between components, foaming control and functional enhancement. The core is the combination of hydrosilylation reaction (driven by vinyl silicone oil, hydrogen-containing silicone oil and platinum catalyst) and foaming agent decomposition and flame retardant carbon layer formation. Under the conditions of low temperature vulcanization foaming and gradient temperature rising process, uniform foam structure, high flame retardancy, mechanical strength and heat resistance are achieved. At the same time, the selection of components focuses on environmental protection (such as halogen-free flame retardant), solving the environmental problems of traditional materials. The roles of each component are complementary: vinyl silicone oil and hydrogen-containing silicone oil provide cross-linked skeleton, hydroxyl silicone oil assists reaction and stability, platinum catalyst accelerates reaction, foaming agent produces gas to form micropores, flame retardant inhibits combustion, reinforcing filler strengthens mechanical properties, vinyl silicone oil as the main polymer skeleton provides vinyl groups for cross-linking reaction with the silicon hydrogen bond of hydrogen-containing silicone oil to form a three-dimensional network structure, giving the material hardness and dimensional stability; hydroxyl silicone oil provides active -OH groups as an auxiliary cross-linking agent and a surfactant to improve the compatibility of the mixture, reduce bubble merging and ensure uniform foaming; platinum catalyst as a catalyst accelerates the hydrosilylation reaction of vinyl silicone oil and hydrogen-containing silicone oil, reduces the reaction temperature and improves the reaction efficiency; the foaming agent decomposes to produce gas (nitrogen, carbon dioxide, etc.) at the vulcanization temperature to form a microporous foam structure, reduce the density of the material and improve the thermal insulation performance; the flame retardant as the core component of the present application inhibits combustion by decomposing heat, generating non-combustible gas and forming an expanded carbon layer. The flame retardant optimizes the thermal stability and flame retardant efficiency; the reinforcing filler plays a physical strengthening role to improve the mechanical strength, rigidity and dimensional stability, and acts as a nucleating agent to promote uniform nucleation of the foam. The overall synergistic improvement of flame retardant performance realizes the synergistic improvement of mechanical strength and heat resistance.

[0027] Compared with the prior art, the present application has the following advantages:

[0028] 1. Significant improvement in flame retardant performance: By adopting a new flame retardant formula and optimizing the foaming process, the material can more effectively inhibit flame spread and reduce the release of toxic gases during combustion, thereby greatly improving the flame retardant safety.

[0029] 2. Enhanced foaming uniformity and dimensional stability: With precise raw material ratio and gradient temperature rising vulcanization process, the foaming process of the material is more uniform and stable, and the dimensional accuracy of the final product is higher, reducing the performance fluctuations caused by uneven foaming.

[0030] 3. Synergistic improvement of mechanical strength and heat resistance: Under the combined action of reinforcing filler and special cross-linked network structure, the material realizes the balance of mechanical strength and heat resistance while ensuring low density, so that it can still maintain excellent performance under high temperature and load conditions. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The nuclear magnetic resonance spectrum of the flame retardant 1 described in the present application. DETAILED DESCRIPTION

[0032] The technical solutions of the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0033] Preparation Example 1

[0034] Preparation of Flame Retardant 1

[0035] ;

[0036] First Step: 20.0 g of raw material 1 was placed in a two-mouth bottle, 200 mL of dichloromethane was added under nitrogen protection, then 38.90 g of 2-(7-azabenzotriazolyl)-N,N,N',N'-tetramethyluronium hexafluorophosphate was added, and stirred at room temperature for 1 h. 11.73 g of raw material 2 was dissolved in 50 mL of dichloromethane and added to the above system, then 12.02 g of N,N-diisopropylethylamine was added under ice water bath, the ice water bath was removed, and the system was stirred at room temperature overnight. After treatment, 200 mL of dichloromethane was added, then washed with 1M hydrochloric acid aqueous solution three times, saturated sodium bicarbonate aqueous solution three times, and saturated brine. The organic phase was dried over anhydrous magnesium sulfate, filtered and rotary evaporated to obtain 23.86 g of intermediate 1. M / Z MS+1: 323.

[0037] Second Step: 23.86 g of intermediate 1, 14.90 g of raw material 3, 39.33 g of potassium phosphate trihydrate, 0.7 g of CuI, 0.09 g of pyridine-2-carboxylic acid and 300 g of DMSO were added to the reaction system under nitrogen atmosphere, and the reaction mixture was heated at 85°C for 16 h; after cooling, the obtained reaction mixture was extracted with ammonia solution and methyl tert-butyl ether, and the organic phase was washed with water five times and then with saturated brine twice; finally, the combined organic phase was dried over anhydrous magnesium sulfate, concentrated, fractionated to obtain 24.36 g of flame retardant 1. The nuclear magnetic resonance spectrum of flame retardant 1 is shown in Figure 1 . M / Z MS+1: 411.

[0038] Flame retardant 1 was identified by nuclear magnetic resonance (Chloroform-d), Figure 1 : δ 7.61 (t, 2H), 7.23 (t, 1H), 6.75 (t, 1H), 6.35 (s, 4H), 4.24-4.09 (m, 6H), 2.36 (d, 3H), 1.37 (t, 6H).

[0039] Preparation Example 2-Preparation Example 4

[0040] Preparation of flame retardants 2-4 in Preparation Examples 2-4 was carried out according to the preparation method of Preparation Example 1, replacing raw material 1 therein, and the rest was the same as Preparation Example 1, as shown in Table 1.

[0041] Table 1

[0042]

[0043] Example 1:

[0044] Preparation of a rigid foamed silicone material:

[0045] 1. Mass ratio of raw materials:

[0046] Vinyl silicone oil: 85 parts, purchased from Hubei Zhonglong Kangsheng Fine Chemical Co., Ltd.;

[0047] Hydrogen-containing silicone oil: 15 parts, purchased from Jinan Longcheng Silicone Co., Ltd.;

[0048] Hydroxyl silicone oil: 20 parts, purchased from Jinan Longcheng Silicone Co., Ltd.;

[0049] Platinum catalyst: 1 part, selected from Kistec catalyst, purchased from Wuhan Lanya Bai Medicine Chemical Co., Ltd., CAS: 68478-92-2;

[0050] Foaming agent: 8 parts, selected from 4,4'-oxybisbenzenesulfonylhydrazide, purchased from Hangzhou Jieheng Chemical Co., Ltd., CAS: 80-51-3;

[0051] Flame retardant: 3 parts, selected from flame retardant 1 prepared in Preparation Example 1;

[0052] Reinforcing filler: 20 parts, selected from quartz powder, purchased from Shanghai Jizhisheng Biochemical Technology Co., Ltd.

[0053] 2. Preparation method:

[0054] S1. Add 85 parts of the vinyl silicone oil, 3 parts of the flame retardant, 8 parts of the foaming agent, and 20 parts of the reinforcing filler into a planetary mixer, and continuously stir at a speed of 600 rpm at room temperature (about 25°C) for 1 hour to ensure uniform mixing of the components, to obtain a premix. Then, the premix is equally divided into an A component premix and a B component premix;

[0055] S2. Add 15 parts of the hydrogen-containing silicone oil to the A component premix, and stir at a speed of 500 rpm at room temperature (about 25°C) for 20 minutes using a planetary mixer until the mixture is uniform, to obtain an A component mixture;

[0056] S3. To the B component premix, add hydroxyl silicone oil 20 parts and platinum catalyst 1 part, stir at room temperature (about 25°C) using a planetary mixer at a speed of 500 rpm for 20 minutes to ensure that the catalyst is fully dispersed, to obtain a B component mixture;

[0057] S4. Mix the A component mixture and the B component mixture quickly and evenly, pour into a mold, and carry out low-temperature vulcanization foaming at 60°C (keep for 30 minutes), then carry out temperature rising vulcanization, first gradient: keep at 75°C for 30 minutes, second gradient: keep at 105°C for 30 minutes, third gradient: keep at 135°C for 60 minutes. Finally, complete vulcanization at 130°C (keep for 60 minutes) to obtain a rigid foamed silicone material.

[0058] Examples 2-4:

[0059] A rigid foamed silicone material is prepared according to the preparation method of Example 1, wherein the flame retardant is replaced by the flame retardants 2-4 prepared in Preparation Examples 2-4, and the rest remains the same as Example 1.

[0060] Comparative Example 1:

[0061] A rigid foamed silicone material is prepared according to the preparation method of Example 1, wherein the flame retardant is replaced by melamine (CAS: 108-78-1, commonly used flame retardant), and the rest remains the same as Example 1.

[0062] Comparative Example 2:

[0063] A rigid foamed silicone material is prepared according to the preparation method of Example 1, wherein the flame retardant is replaced by melamine phosphate (CAS: 20208-95-1, commonly used flame retardant), and the rest remains the same as Example 1.

[0064] Comparative Example 3:

[0065] A rigid foamed silicone material is prepared according to the preparation method of Example 1, wherein the flame retardant is replaced by magnesium hydroxide (CAS: 1309-42-8, commonly used flame retardant), and the rest remains the same as Example 1.

[0066] Comparative Example 4:

[0067] A rigid foamed silicone material is prepared according to the preparation method of Example 1, wherein the flame retardant is not added, and the rest remains the same as Example 1.

[0068] Comparative Example 5:

[0069] A rigid foamed silicone material is prepared according to the preparation method of Example 1, wherein the hydroxyl silicone oil is not added, and the rest remains the same as Example 1.

[0070] Performance testing:

[0071] 1. The limiting oxygen index of a rigid foamed silicone material prepared according to the test examples and comparative examples in GB / T2406.1-2008 is shown in Table 2.

[0072] 2. A rigid foamed silicone material prepared in the examples and comparative examples was used to prepare standard test strips according to UL94 standard for flame retardant performance testing. The results are shown in Table 2.

[0073] 3. The Shore A hardness of a rigid foamed silicone material prepared in the examples and comparative examples was tested according to GB / T 531.1-2008, and the results are shown in Table 2.

[0074] 4. The compression properties of a rigid foamed silicone material prepared in the examples and comparative examples were tested according to GB / T 18942.2-2003, with a compression of 50%. The results are shown in Table 2.

[0075] Table 2

[0076]

[0077] Table 2 shows that the materials in the examples exhibit higher performance levels compared to the comparative samples in key performance indicators such as limiting oxygen index, vertical flammability rating, Shore A hardness, and compressive strength, especially in flame retardancy, achieving a higher level of fire resistance. In contrast, the comparative samples without added flame retardants or using traditional flame retardants showed significantly poorer flame retardancy, and their hardness and compressive strength also decreased to varying degrees. This indicates that formulation optimization can effectively improve the overall performance of the materials, meeting the demands of more demanding application scenarios.

[0078] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rigid foamed silicone material, characterized in that, It is prepared from the following components in parts by weight: vinyl silicone oil: 80-100 parts, hydrogen-containing silicone oil: 5-20 parts, hydroxyl silicone oil: 15-25 parts, platinum catalyst: 0.1-2 parts, foaming agent: 3-15 parts, flame retardant: 2-5 parts, reinforcing filler: 10-30 parts. The flame retardant is a compound represented by Formula 1: Formula 1: ; In Formula 1, R1 is a substituent, and R1 is selected from: methyl, ethyl, amino, and cyano. The method for preparing the rigid foamed silicone material includes the following steps: S1. Add the vinyl silicone oil, flame retardant, foaming agent, and reinforcing filler to a planetary mixer and stir at room temperature for 1 hour to obtain a premix. Divide the premix into component A premix and component B premix. S2. Add the hydrogen-containing silicone oil to the premix of component A, stir evenly, and obtain the mixture of component A; S3. Add the hydroxyl silicone oil and platinum catalyst to the premix of component B, stir evenly, and obtain the mixture of component B; S4. Mix component A and component B evenly, vulcanize and foam at a low temperature of 55-65℃, then vulcanize at a higher temperature, and finally vulcanize at 130℃ to obtain a rigid foamed silicone material. In step S4, the temperature rise and vulcanization are divided into three gradients, with temperatures of 70-80℃, 100-110℃, and 130-140℃ respectively.

2. The rigid foamed silicone material according to claim 1, characterized in that, The vinyl silicone oil has a vinyl content of 0.1%-6% and a viscosity of 500-10000 mPa·s.

3. The rigid foamed silicone material according to claim 1, characterized in that, The hydrogen-containing silicone oil has a hydrogen content of 0.5%-1.5% and a viscosity of 100-500 mPa·s.

4. The rigid foamed silicone material according to claim 1, characterized in that, The hydroxyl content of the hydroxyl silicone oil is 0.4%-7%.

5. A rigid foamed silicone material according to claim 1, characterized in that, The platinum catalyst is at least one of the following: a cassiterite catalyst, a diethylene octamethyltetrasiloxane platinum complex, and a diethyl chloroplatinate phthalate complex.

6. The rigid foamed silicone material according to claim 1, characterized in that, The foaming agent is at least one of 4,4'-oxobis(benzenesulfonyl)hydrazine or azodicarbonamide.

7. A rigid foamed silicone material according to claim 1, characterized in that, The reinforcing filler is quartz powder.

8. A rigid foamed silicone material according to claim 1, characterized in that, The flame retardant is selected from any one of the compounds shown in the following structures: ； 。

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