High-temperature-resistant heat-proof coating material and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant heat-proof coating material and a preparation method thereof, and aims to solve the problems that the existing organic heat-proof coating material is poor in shape maintaining property and insufficient in mechanical strength at high temperature. The coating material disclosed by the invention is prepared from the following raw materials in parts by mass: 0.5 to 5 parts of octa-aminopropyl polyhedral oligomeric silsesquioxane, 80 to 120 parts of hydroxyl-terminated polymethylphenylsiloxane, 3 to 12 parts of curing agent, 0.1 to 5 parts of catalyst, 20 to 80 parts of low-temperature bonding glass material and 20 to 80 parts of high-temperature melt eutectic mineral aggregate. By increasing the rigidity of the matrix resin and combining the characteristics of the low-temperature bonding glass material and the high-temperature melting eutectic mineral material, the organosilicone heat-proof coating capable of being vitrified at high temperature is prepared, and then the shape maintaining property and the mechanical property of the protective material in a wide temperature range are improved.

Description

Technical Field

[0001] The invention relates to a high-temperature coating material, and in particular to a high-temperature resistant heat-proof coating material and a preparation method thereof. Background Art

[0002] Organic heat-resistant coatings are used as heat-insulating layers on the outer surface of building walls and as large-area lightweight heat-protective materials on the leeward side of high-speed aircraft. They are used for heat protection and insulation. In practical applications, organic heat-resistant coatings are required to have high bending strength and good heat resistance at high temperatures. Moreover, the cracking products need to maintain a stable morphology at high temperatures, so as to ensure that the organic heat-resistant materials can still play a good role in heat protection and insulation under the external heat and force coupling.

[0003] However, the matrix used in existing organic heat-resistant materials degrades quickly at high temperatures (over 800°C) and has low residues. In addition, the coating ablation products have a loose structure, severe expansion, and low self-strength. They are easy to fall off under external force and are difficult to play an effective protective role. As a result, the organic heat-resistant coating is prone to structural failure and poor dimensional shape in high-temperature environments. Summary of the invention

[0004] In view of the defects or shortcomings of the prior art, the present invention provides a high-temperature resistant and heat-proof coating material.

[0005] To this end, the raw materials for preparing the coating material provided by the present invention include: 0.5-5 parts by mass of octaaminopropyl polyhedral oligomeric silsesquioxane, 80-120 parts by mass of hydroxyl-terminated polymethylphenylsiloxane, 3-12 parts by mass of a curing agent, 0.1-5 parts by mass of a catalyst, 20-80 parts by mass of a low-temperature bonding glass material, and 20-80 parts by mass of a high-temperature melting eutectic mineral material;

[0006] The curing agent is a mixture of one or more of tetraethyl orthosilicate, butyl orthosilicate, ethyl orthosilicate, aminopropyltriethoxysilane and methyltriethoxysilane;

[0007] The catalyst is a mixture of one or more of dibutyltin dilaurate, dibutyltin acetate and dioctyltin dilaurate;

[0008] The low-temperature bonding glass frit is a mixture of one or more of glass powder, ammonium polyphosphate and glass fiber powder;

[0009] The high temperature molten eutectic mineral material is a mixture of one or more of mica, wollastonite, fumed silica and red iron.

[0010] The present invention also provides a method for preparing the above coating material, the preparation method comprising:

[0011] (1) dissolving octaaminopropyl polyhedral oligomeric silsesquioxane in an organic solvent, adding hydroxyl-terminated polymethylphenyl silicone rubber, mixing evenly, and drying at 65-75° C. to obtain an organic silicon matrix;

[0012] (2) adding low-temperature bonding glass material and high-temperature melting eutectic mineral material to the organosilicon matrix, mixing them evenly and then standing to obtain a mixed rubber;

[0013] (3) Add a curing agent and a catalyst to the mixed rubber, mix well, and then cure at room temperature to obtain a coating material.

[0014] The matrix material of the present invention is hydroxyl-terminated polysiloxane, and by blending EA-POSS in the polysiloxane matrix, the heat resistance of the coating can be effectively improved without the need for special equipment and complicated operation processes.

[0015] Furthermore, the coating material of the present invention has a stable morphology at high temperatures, good dimensional properties, a smooth surface without bulges under flame ablation, and can play a good shielding role in an external high-temperature environment.

[0016] In addition, the coating material of the present invention has excellent bending strength and can resist thermal stress and external mechanical force erosion through the combined action of matrix decomposition products and heat-resistant fillers at high temperatures.

[0017] In addition, the coating material of the present invention has a simple preparation process, low energy consumption, and can broaden the application range of the coating. The coating can be fully cured at room temperature, so high temperature and high pressure equipment are not required. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The high-temperature morphologies of the coating materials prepared in the embodiments and comparative examples of the present invention are shown in Figure 5; (A) shows the high-temperature morphologies of Embodiment 1, Comparative Examples 1 and 2; and (B) shows the high-temperature morphologies of Comparative Examples 3-6. DETAILED DESCRIPTION

[0019] Unless otherwise specified, the scientific and technical terms used herein are understood according to the knowledge of ordinary technicians in the relevant fields.

[0020] The coating matrix of the present invention uses octaaminopropyl polyhedral oligomeric silsesquioxane (EA-POSS) to reinforce polymethylphenylsiloxane, and utilizes the cage structure of POSS to enhance the rigidity of the flexible main chain, thereby inhibiting the cyclization degradation of polysiloxane at high temperature; then low-temperature bonding glass material and high-temperature melting eutectic mineral material are added thereto, and mechanical stirring is used to achieve uniform dispersion, wherein: the low-temperature bonding glass material can soften and flow during the heating process to decompose the matrix, thereby filling the gaps generated by the escape of cracked gas; the high-temperature melting eutectic mineral material combines with other components at a higher temperature to generate a new ceramic phase, thereby playing a good toughening and strengthening role, thereby ensuring the bending performance of the coating at high temperature.

[0021] The technical solution of the present invention is further described below, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the protection scope of the present invention. The raw materials used in the following examples are all commercially available products.

[0022] Embodiment 1:

[0023] The raw materials and preparation method of the coating material in this embodiment are:

[0024] Add an appropriate amount of tetrahydrofuran to 1g of octaaminopropyl polyhedral oligomeric silsesquioxane to fully dissolve it to obtain a POSS solution; add 100g of hydroxyl-terminated polymethylphenylsiloxane (the hydroxyl-terminated polymethylphenylsiloxane used in this embodiment has a phenyl molar percentage content of 10% and a molecular weight of 9800) to the POSS solution and stir rapidly, place it under ultrasonic conditions for 12h for uniform dispersion after preliminary mixing, and then place it in an oven at about 70°C for heating and drying for 72h to obtain an organosilicon matrix EA-POSS modified polymethylphenylsiloxane;

[0025] The prepared EA-POSS modified polymethylphenylsiloxane of aforesaid method is placed on a three-roll mill and ground, the low temperature bonding glass frit (glass powder 30g wherein, glass fiber powder 20g) of 50g and the high temperature melting eutectic mineral material (iron red 3g wherein, wollastonite 30g, aerosil 47g) of 80g are added in a plurality of batches in the EA-POSS modified polymethylphenylsiloxane after the grinding and continue to fully mix on a three-roll mill, after mixing half an hour, leave standstill one day, obtain rubber unvulcanizate after the elimination of internal stress;

[0026] 7 g of curing agent (including 4 g of tetraethyl orthosilicate and 3 g of aminopropyltriethoxysilane) and 0.8 g of catalyst (dibutyltin dilaurate) were added dropwise into the mixed rubber and the mixing was continued until uniform.

[0027] The dispersed cement was then placed in a 200 mm × 200 mm × 2 mm three-plate mold coated with polytetrafluoroethylene, pressurized at room temperature to prepare a sheet sample, and then cured at room temperature for one week to obtain the sheet coating material of this embodiment. The obtained coating material was tested as follows:

[0028] High temperature morphology: The sample was placed in a muffle furnace and ablated at 800°C for 10 minutes, and then its morphology was photographed after it was placed at room temperature. Figure 1 As shown, the surface after ablation is smooth and has no cracks, and the original morphology can be well maintained;

[0029] High temperature bending performance: A 3-point bending test was conducted using an electronic universal tensile machine. The sample was ablated in a muffle furnace at 800°C for 10 minutes and then tested after cooling to room temperature. The maximum force of the testing machine is 50kN, the test rate is 0.5mm / min, and the high temperature bending strength is 6.59MPa.

[0030] Thermal insulation performance test: The back temperature of the coating sample after 600s of ablation is tested with a quartz lamp to illustrate its thermal insulation performance. It can be seen that the back temperature without coating protection can reach about 700°C, while the back temperature after coating is reduced to 269°C.

[0031] Comparative Example 1:

[0032] The difference between this comparative example and Example 1 is that the raw materials used in the preparation do not contain high-temperature molten eutectic mineral materials. Figure 1 It can be seen that after ablation at 800°C, white objects escaped from the surface and there were debris. It could not maintain its original morphology, making it difficult to test its bending strength.

[0033] Comparative Example 2:

[0034] The difference between this comparative example and Example 1 is that the raw materials used in the preparation do not contain low temperature bonding glass material. Figure 1 It can be seen that it expands and breaks after ablation at 800°C, the structure is easily powdered, and it has no strength itself, making it difficult to test its bending strength.

[0035] Comparative Example 3:

[0036] The difference between this comparative example and Example 1 is that an equal amount of talc is used to replace the high temperature molten eutectic mineral material. Figure 1 It can be seen that it expands and powders after ablation at 800°C, making it difficult to test its bending strength.

[0037] Comparative Example 4:

[0038] The difference between this comparative example and Example 1 is that an equal amount of bentonite is used to replace the high temperature molten eutectic mineral material. Figure 1 It can be seen that it expands and powders after ablation at 800°C, making it difficult to test its bending strength.

[0039] Comparative Example 5:

[0040] The difference between this comparative example and Example 1 is that the low temperature bonding glass frit is replaced by an equal amount of zinc borate. Figure 1 It can be seen that it completely shattered after ablation at 800°C, and a large amount of white powder escaped, making it difficult to test its bending strength.

[0041] Comparative Example 6:

[0042] The difference between this comparative example and Example 1 is that the low-temperature bonding glass frit is replaced by an equal amount of boron oxide. Figure 1 It can be seen that it expanded and broke after ablation at 800°C, with a large amount of white powder escaping, making it difficult to test its bending strength.

[0043] Embodiment 2:

[0044] This embodiment is different from embodiment 1 in that the raw materials for preparation of this embodiment are:

[0045] 5g octaaminopropyl polyhedral oligomeric silsesquioxane, 120g hydroxyl-terminated polymethylphenylsiloxane, 80g low-temperature bonding glass material (including 40g glass powder and 40g ammonium polyphosphate), 60g high-temperature melting eutectic mineral material (including 2g iron red, 23g mica, and 35g wollastonite), 12g curing agent (including 7g butyl orthosilicate and 5g methyltriethoxysilane) and 5g catalyst (dibutyltin acetate).

[0046] Embodiment 3:

[0047] This embodiment is different from embodiment 1 in that the raw materials for preparation of this embodiment are:

[0048] 0.5g octaaminopropyl polyhedral oligomeric silsesquioxane, 80g hydroxyl-terminated polymethylphenylsiloxane, 20g low-temperature bonding glass material (including 10g glass powder and 10g glass fiber powder), 20g high-temperature melting eutectic mineral material (including 5g mica, 8g wollastonite, and 7g fumed silica), 3g curing agent (including 1g tetraethyl orthosilicate and 2g aminopropyltriethoxysilane) and 0.1g catalyst (dibutyltin acetate).

Claims

1. A high temperature resistant heat-proof coating material, characterized in that: The raw materials for preparing the coating material include: 0.5-5 parts by weight of octaaminopropyl polyhedral oligomeric silsesquioxane, 80-120 parts by weight of hydroxyl-terminated polymethylphenylsiloxane, 3-12 parts by weight of a curing agent, 0.1-5 parts by weight of a catalyst, 20-80 parts by weight of a low-temperature bonding glass material, and 20-80 parts by weight of a high-temperature melting eutectic mineral material; The curing agent is a mixture of one or more of tetraethyl orthosilicate, butyl orthosilicate, ethyl orthosilicate, aminopropyltriethoxysilane and methyltriethoxysilane; The catalyst is a mixture of one or more of dibutyltin dilaurate, dibutyltin acetate and dioctyltin dilaurate; The low-temperature bonding glass frit is a mixture of one or more of glass powder, ammonium polyphosphate and glass fiber powder; The high temperature molten eutectic mineral material is a mixture of one or more of mica, wollastonite, fumed silica and red iron.

2. The method for preparing the coating material according to claim 1, characterized in that: The preparation method comprises: (1) dissolving octaaminopropyl polyhedral oligomeric silsesquioxane in an organic solvent, adding hydroxyl-terminated polymethylphenyl silicone rubber, mixing evenly, and drying at 65-75° C. to obtain an organic silicon matrix; (2) adding low-temperature bonding glass material and high-temperature melting eutectic mineral material to the organosilicon matrix, mixing them evenly and then standing to obtain a mixed rubber; (3) Add a curing agent and a catalyst to the mixed rubber, mix well, and then cure at room temperature to obtain a coating material.

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