A ceramic fire-resistant silicone rubber resistant to flame impact

Abstract

The present invention belongs to the technical field of silicone rubber, and specifically relates to a ceramic fire-resistant silicone rubber resistant to flame impact, comprising the following components calculated by weight percentage: 5-10% polydimethylsiloxane, 25-30% vinyl polydimethylsiloxane, 2-5% polymethyl hydrogen siloxane, 10-20% mica powder, 35-58% thermal conductive filler, and 1-5% silane coupling agent. The present invention has excellent elasticity and electrical insulation properties at room temperature like ordinary rubber, silicone rubber and thermoplastic elastomer. In addition, it also has excellent fire resistance and flame retardancy under high temperature conditions, and can form a ceramic-like hard protective layer after ablation under high temperature conditions of 1300°C, which plays a fireproof role and reduces the spread of flames.

Description

Technical Field

[0001] The invention belongs to the technical field of silicone rubber, and in particular relates to a ceramic fire-resistant silicone rubber resistant to flame impact. Background Art

[0002] In many industrial fields, such as aerospace, automobile manufacturing, electronic appliances, etc., materials need to be able to remain stable in extremely high temperature and flame impact environments, and have good insulation and sealing properties. Ceramic fire-resistant silicone rubber is a new type of material with excellent high temperature resistance and flame impact resistance, which can withstand high temperature and flame impact in a short period of time. However, the flame impact resistance temperature of most fire-resistant silicone rubbers on the market currently does not exceed 1200℃, and the formula is complex, which is not conducive to simplifying operation, and significant quality loss and degradation will still occur at higher ambient temperatures. Summary of the invention

[0003] The technical problem solved by the present invention is to provide a ceramic fire-resistant silicone rubber resistant to flame impact, which has excellent elasticity and electrical insulation properties at room temperature like ordinary rubber, silicone rubber and thermoplastic elastomer. In addition, it also has excellent fire resistance and flame retardancy under high temperature conditions, and can form a ceramic-like hard protective layer after ablation under high temperature conditions of 1300°C, which plays a fire-proof role and reduces the spread of flames.

[0004] The present invention solves the above problems through the following technical solutions:

[0005] The invention provides a ceramic fire-resistant silicone rubber resistant to flame impact. The preparation raw materials include the following components calculated by mass percentage: 5-10% of polydimethylsiloxane, 25-30% of vinyl polydimethylsiloxane, 2-5% of polymethyl hydrogen siloxane, 10-20% of mica powder, 35-58% of thermal conductive filler and 1-5% of silane coupling agent.

[0006] Furthermore, the vinyl polydimethylsiloxane is vinyl-terminated polydimethylsiloxane.

[0007] Furthermore, the thermally conductive filler is preferably aluminum hydroxide.

[0008] Furthermore, the silane coupling agent includes one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, among which the diamino vulcanizing agent is preferred.

[0009] On the other hand, the present invention also provides a method for preparing the above-mentioned flame-impact-resistant ceramicized refractory silicone rubber, which can be carried out using any suitable equipment and includes the following steps: uniformly stirring polydimethylsiloxane, vinyl polydimethylsiloxane, polymethyl hydrogen siloxane, mica powder, silane coupling agent and thermal conductive filler, adding a vulcanizing agent and pouring it into a mold for casting, and then placing the cast mold into a vulcanizer for vulcanization treatment.

[0010] Furthermore, the stirring time is 10-20 minutes, and sufficient mixing can be achieved until a uniform mixture is formed.

[0011] Furthermore, the pouring temperature is 20-40° C., which ensures that the mixture will not be stratified and decomposed during the pouring process and can adapt to the subsequent vulcanization process to obtain the required physical properties and high temperature resistance.

[0012] Furthermore, the vulcanization temperature is 150-200° C. and the vulcanization time is 2-3 hours, so as to accelerate the cross-linking reaction and form a hardened silicone rubber product.

[0013] Furthermore, the vulcanizing agent can be used in an amount known to those skilled in the art, which can accelerate the vulcanization speed, shorten the vulcanization time, reduce the amount of the vulcanizing agent used, or lower the vulcanization temperature.

[0014] The beneficial effects of the present invention are as follows: the ceramicized refractory silicone rubber of the present invention has a simple formula, can be ceramicized within a temperature range of 350-800°C, and can be sintered into a porous self-supporting ceramic body, which does not absorb moisture or water, is easy to store, has superior mechanical strength and electrical insulation, and has excellent flame retardant properties, and can withstand high-temperature flame impacts of 1300°C without causing cracking or damage. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited thereto. The methods involved in the present invention are all commonly used methods in the art unless otherwise specified, and the reagents involved are all available from common commercial channels unless otherwise specified.

[0016] The following Table 1 is a silicone rubber formula table of Examples 1-3 and Comparative Examples 1-3.

[0017] Table 1

[0018]

[0019] The preparation of the above embodiment comprises the following steps:

[0020] Stir polydimethylsiloxane, vinyl polydimethylsiloxane, polymethyl hydrogensiloxane, mica powder, silane coupling agent and thermal conductive filler for 15 minutes until uniform, add appropriate amount of dipentadienyl vulcanizer and pour into the mold for casting at room temperature, and then put the cast mold into a vulcanizer and vulcanize at 150°C for 2 hours.

[0021] The preparation steps of the comparative example can be obtained by referring to the examples.

[0022] The above embodiments and comparative examples were tested for performance, and the results are shown in Table 2 below. The test method is:

[0023] 1. Appearance: Visual inspection

[0024] 2. Density: GB / T 533-2008

[0025] 3. Tensile strength: GB / T 528

[0026] 4. Breakdown voltage strength: GB / T 1695-2005

[0027] 5. Volume resistivity: GB / T 1410-2006

[0028] 6. Insulation resistance: GB / T 10581, 800℃

[0029] 7. Water absorption: GB / T 1034-2008

[0030] 8. Dielectric constant: GB / T 1693-2007, 50Hz

[0031] 9. Flame retardancy: UL 94, 3mm thickness

[0032] 10. Smoke toxicity: GB / T 20285-2006

[0033] 11. Flame impact resistance: Clamp a sample of 8cm×8cm and 1mm thickness with a bracket, use a propane flame to aim at the center of the sample and burn it continuously for 30 minutes. The sample is 2cm away from the flame outlet, and the burning center temperature exceeds 1300℃.

[0034] Table 2

[0035]

[0036]

[0037] The above results show that the ceramic fire-resistant silicone rubber provided by the present invention has excellent elasticity and electrical insulation properties, as well as excellent fire resistance and flame retardancy under high temperature conditions, and can withstand high temperature flame impact of 1300°C.

[0038] It can be understood that the above specific embodiments are all further explanations of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, all other modifications and changes obtained without creative work are within the scope of protection of the present invention.

Claims

1. A ceramic fire-resistant silicone rubber resistant to flame impact, characterized in that: The raw materials for preparation include the following components calculated by weight percentage: 5-10% polydimethylsiloxane, 25-30% terminal vinyl polydimethylsiloxane, 2-5% polymethyl hydrogen siloxane, 10-20% mica powder, 35-58% thermal conductive filler, and 1-5% silane coupling agent; The silane coupling agent includes one of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

2. The ceramic refractory silicone rubber according to claim 1, characterized in that: The thermally conductive filler is aluminum hydroxide.

3. Use of the ceramic fire-resistant silicone rubber according to any one of claims 1 to 2 in blocking the impact of flames above 1300°C.

4. A method for preparing the ceramic refractory silicone rubber according to any one of claims 1 to 2, characterized in that: The following steps are involved: Polydimethylsiloxane, vinyl polydimethylsiloxane, polymethyl hydrogen siloxane, mica powder, silane coupling agent and thermal conductive filler are mixed evenly, and a vulcanizing agent is added and poured into a mold for casting, and then the cast mold is placed in a vulcanizer for vulcanization treatment.

5. The method for preparing ceramic refractory silicone rubber according to claim 4, characterized in that: The stirring time is 10-20 min.

6. The method for preparing ceramic refractory silicone rubber according to claim 4, characterized in that: The pouring temperature is 20-40°C.

7. The method for preparing ceramic refractory silicone rubber according to claim 4, characterized in that: The vulcanization temperature is 150-200° C., and the vulcanization time is 2-3 hours.

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