A room-temperature curable high-insulation ablative-resistant and heat-insulating coating, coating layer and preparation method thereof

Abstract

The present invention provides a room-temperature curable high-insulation ablation-resistant and heat-insulating coating, a coating layer and a preparation method thereof, which comprise raw materials in the following parts by mass: 100 parts of a resin matrix; 15-30 parts of a nano-scale reinforcing filler; 10-20 parts of a micro-scale reinforcing filler; 20-35 parts of an organic ablation-resistant filler; 2-5 parts of a curing agent; the resin matrix is a phenyl addition-type silicone resin, the nano-scale reinforcing filler is hydrophobic modified silica, the micro-scale reinforcing filler is a coupling agent-modified silicon-based inorganic fiber; the organic ablation-resistant filler is an aramid or polyetherimide powder filler with an electropositive benzene ring. Through appropriate molecular structure design and filler component regulation, the present invention achieves a relatively regular coating stacking structure, and solves the problem that the existing ablation-resistant and heat-insulating coatings cannot have high insulation performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface engineering, and in particular relates to a room temperature curing high-insulation ablation-resistant heat-resistant paint, a coating and a preparation method thereof. Background Art

[0002] Silicone materials, due to their unique organic-inorganic hybrid structure, have excellent high-temperature resistance and are widely used in the field of thermal protective coatings. Due to thermal protection requirements, the outer surfaces of special equipment such as military equipment and civilian power transmission equipment often require large areas and thick layers of ablation-resistant and heat-resistant coatings made of silicone rubber systems. However, with the development of military equipment and special equipment manufacturing industries, high insulation performance requirements have been put forward for ablation-resistant coatings. This is because military equipment and power transmission equipment often have strong electric field effects due to special circumstances such as the voltage around the equipment. The insulation performance of current ablation-resistant and heat-resistant coating materials is generally poor, which can easily lead to electrical breakdown of the coating. Currently, the most widely used silicone rubber thermal barrier coatings in China are the TR-37, TR-42, and TR-52 series developed by the Institute of Aerospace Materials and Technology. These coatings offer excellent ablation resistance and can meet the thermal protection requirements of equipment. However, due to issues with the matching of their resin and filler, their breakdown field strength is low, generally below 6kV / mm, making it difficult to meet the current insulation performance requirements for ablation-resistant coatings, thus seriously affecting equipment reliability. Silicone high-temperature insulating varnishes commonly used on the exterior surfaces of civilian cables and other applications contain fewer fillers, making thick coatings difficult to achieve. Furthermore, they suffer from poor ablation resistance and poor workability, making them difficult to apply in the ablation-resistant coating field.

[0003] Therefore, there is an urgent need for a room temperature curing high insulation, ablation-resistant and heat-resistant coating. Through appropriate molecular structure design and filler component regulation, a relatively regular coating stacking structure can be achieved, in order to take into account the needs of ablation resistance and high insulation. Summary of the Invention

[0004] In order to overcome the deficiencies in the prior art, the inventors have conducted intensive research and provided a room temperature curing high insulation, ablation-resistant, heat-resistant coating, a coating and a preparation method thereof. By optimizing the design of the resin matrix composition, formula compounding design and optimization, the inventors have solved the problem that the existing ablation-resistant, heat-resistant coatings cannot have high insulation performance, and achieved a protective effect that takes both high insulation and good ablation resistance into account.

[0005] The technical solutions provided by the present invention are as follows:

[0006] In a first aspect, a room temperature curing high insulation, ablation-resistant and heat-resistant coating comprises the following raw materials in parts by weight:

[0007]

[0008] In a second aspect, a room-temperature curable high-insulation ablation-resistant and heat-insulating coating is prepared from the room-temperature curable high-insulation ablation-resistant and heat-insulating coating material described in the first aspect.

[0009] In a third aspect, a method for preparing a room-temperature curable high-insulation ablation-resistant and heat-insulating coating material includes:

[0010] Uniformly dispersing a resin matrix and a nano-scale reinforcing filler according to a ratio to obtain Reinforcement 1;

[0011] Adding a micron-scale reinforcing filler to Reinforcement 1 according to a ratio to obtain Reinforcement 2;

[0012] Adding an organic ablation-resistant filler to Reinforcement 2 according to a ratio to obtain Component A of the coating material;

[0013] Mixing Component A of the coating material and a curing agent uniformly according to a ratio, adding a diluent for dilution, and then preparing a room-temperature curable high-insulation ablation-resistant and heat-insulating coating material.

[0014] In a fourth aspect, a method for preparing a room-temperature curable high-insulation ablation-resistant and heat-insulating coating includes:

[0015] Spraying the room-temperature curable high-insulation ablation-resistant and heat-insulating coating material on the surface of a polished substrate, curing at room temperature for more than 72 h or curing at room temperature for 12 - 24 h and then heating and curing at 60 - 80 °C for more than 10 h to obtain the coating.

[0016] According to the room-temperature curable high-insulation ablation-resistant and heat-insulating coating material, coating and its preparation method provided by the present invention, the following beneficial effects are achieved:

[0017] (1) For the room-temperature curable high-insulation ablation-resistant and heat-insulating coating material, coating and its preparation method provided by the present invention, by designing and preparing a room-temperature curable phenyl addition-type silicone rubber with a regular stacked molecular structure and a large steric hindrance as the main film-forming substance, adjusting the polymer chain stacking behavior through the benzene ring structure, further reducing the free volume between molecules, and increasing the breakdown threshold of the matrix film-forming substance, greatly improving the insulation property of the silicone rubber itself;

[0018] (2) For the room-temperature curable high-insulation ablation-resistant and heat-insulating coating material, coating and its preparation method provided by the present invention, by adding an organically surface-modified nano-scale reinforcing filler and a micron-scale reinforcing filler, improving the interfacial bonding force between the filler and the matrix, reducing the spatial defects caused by the introduction of the filler, and taking into account the ablation resistance and high insulation of the coating;

[0019] (3) The present invention provides a room temperature curing high insulation ablation resistant heat-resistant coating, coating and preparation method thereof, which further improves the ablation resistance of the coating by adding organic component aramid, polyetherimide and other powder fillers (benzene ring with + charge) that have electrostatic attraction with the benzene ring (with - charge) of phenyl silicone rubber. At the same time, since the benzene ring on the silicone rubber and the benzene ring of the organic component have opposite charges, the two can be effectively stacked, reducing the generation of defective structures, and the breakdown field strength is as high as 15kV / mm or more;

[0020] (4) The present invention provides a room temperature curing high insulation ablation resistant heat-resistant coating, coating and its preparation method, the coating has excellent ablation resistance, and a 5.0mm coating can pass a maximum of 370kW / m 2 The wind tunnel test assessment shows that the back temperature is ≤180℃ and the coating does not peel off; the preparation process is simple, the solid content of the coating is ≥70% and it can be cured at room temperature. It is easy to apply and can be applied on a large area by brushing, spraying, roller coating, dipping, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the contact angle of silica before and after hydrophobic modification;

[0022] Figure 2 This is a photo of the coating after wind tunnel testing in Example 1. DETAILED DESCRIPTION

[0023] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0024] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0025] The present invention provides a room temperature curing high insulation, ablation-resistant and heat-resistant coating, comprising the following raw materials in parts by weight:

[0026]

[0027] In a preferred embodiment, the resin matrix is a phenyl addition type silicone resin, including 0-20% of a difunctional phenyl vinyl silicone oil with a molecular weight of 7000-10000, 40%-60% of a multifunctional phenyl vinyl silicone resin with a molecular weight of 1000-1500, 20%-40% of a difunctional phenyl hydrogen silicone oil with a molecular weight of 200-400, 0.5%-2% of an adhesion promoter and 0.1%-1.0% of an inhibitor.

[0028] Among them, the adhesion promoter is selected from at least one of PR1200, Tego AddBond LTW, Tackifier Adhesionpromoter SK-Z04, and KH560.

[0029] The inhibitor is selected from at least one of 3-methyl-1-butyn-3-ol, 1-ethynyl-1-cyclohexanol, and 3-methyl-1-pentyn-3-ol.

[0030] The phenyl addition type silicone resin is mainly prepared by the addition reaction of vinyl and silicon-hydrogen bonds. Among them, multifunctional phenyl vinyl silicone resin and bifunctional phenyl vinyl silicone oil are used to adjust the crosslinking degree and flexibility of the final resin respectively. The higher the proportion of the former, the greater the crosslinking density of the final resin. Therefore, the mechanical properties of the resin are mainly regulated by adjusting the proportion and molecular weight of the two. At the same time, the phenyl content can be regulated by the ratio of the two. Generally speaking, the higher the phenyl content, the higher the breakdown field strength of the subsequent resin. And the bifunctional phenyl hydrogen-containing silicone oil is used as a crosslinking agent, and its content is determined by the total sum of vinyl functional groups in the former two.

[0031] At the same time, by designing a room temperature curing phenyl addition type silicone rubber with a regularly stacked molecular structure and large steric hindrance as the main film-forming substance, the stacking behavior of polymer chains is adjusted through the benzene ring structure, further reducing the free volume between molecules and increasing the breakdown threshold of the matrix film-forming substance, greatly improving the insulation of the silicone rubber itself.

[0032] In a preferred embodiment, the nano-scale reinforcing filler is hydrophobic modified silica, the modifier is hexamethyldisilazane, the particle size is 5 - 20 nm, and the contact angle is 130 - 135°. The modification method is high-temperature reflux method.

[0033] In a preferred embodiment, the micro-scale reinforcing filler is at least one of silicon-based inorganic fibers such as high silica fiber and quartz fiber, the fiber length is 100 - 450 μm, and the surface is modified with one of γ-methacryloxypropyltrimethoxysilane (KH570), KH560, or KH550. The modification method is ultrasonic pretreatment method, the ethanol solution concentration of the coupling agent is 10% - 20%, and the treatment time is 1 - 2 h.

[0034] In a preferred embodiment, the organic ablation-resistant filler is powder fillers such as aramid and polyetherimide with an electropositive benzene ring.

[0035] In a preferred embodiment, the curing agent is a platinum catalyst with a platinum content of 3000 ppm - 6000 ppm.

[0036] In a preferred embodiment, the diluent is selected from butyl acetate, 120# gasoline, etc.

[0037] The present invention also provides a room-temperature curable high-insulation ablative-resistant and heat-insulating coating, which is prepared from the room-temperature curable high-insulation ablative-resistant and heat-insulating coating material described in the first aspect, and the coating thickness reaches 2.0 - 6.0 mm.

[0038] The breakdown field strength of the 5-mm coating is as high as over 15 kV / mm, and it can pass the wind tunnel experiment assessment with a maximum of 370 kW / m 2 . The back temperature ≤ 180 °C, and the coating shows no peeling.

[0039] The present invention provides a preparation method for a room-temperature curable high-insulation ablative-resistant and heat-insulating coating, which includes the following steps:

[0040] (1) Preparation of Reinforcement 1: The resin matrix and nano-scale reinforcing fillers are uniformly dispersed using a three-roll mill according to the ratio to obtain Reinforcement 1;

[0041] (2) Preparation of Reinforcement 2: Modified micron-scale reinforcing fillers are added to Reinforcement 1 according to the ratio to obtain Reinforcement 2;

[0042] (3) Preparation of Component A of Ablative-Resistant Coating: Organic ablative-resistant fillers are added to Reinforcement 2 according to the ratio to obtain Component A of the coating.

[0043] (4) Preparation of Coating Sample: The obtained Component A of the coating and the curing agent are mixed evenly, diluted with a diluent, and then sprayed on the surface of the polished substrate. After curing at room temperature for more than 72 h or curing at room temperature for 12 - 24 h and then heating and curing at 60 - 80 °C for more than 10 h, the preparation of the coating sample is achieved, which has good economic and social benefits.

[0044] Examples / Comparative Examples

[0045] Example 1

[0046]

[0047] Among them, the silicone resin includes: 16% of difunctional phenyl vinyl silicone oil with a molecular weight of 7000 - 8000, 55% of trifunctional phenyl vinyl silicone resin with a molecular weight of 1000 - 1400, 28% of difunctional phenyl hydrogen-containing silicone oil with a molecular weight of 300 - 400, 0.5% of PR1200, and 0.5% of inhibitor 3-methyl-1-pentyn-3-ol.

[0048] The white carbon black modified with hexamethyldisilazane is modified by the high-temperature reflux method, and the contact angle after modification is 133.2°, as shown in Figure 1 .

[0049] The modification method of KH570-modified high-silica fiber is ultrasonic pretreatment method, the ethanol solution concentration of the coupling agent is 10%, and the treatment time is 1 h.

[0050] The coating preparation process of this embodiment includes the following steps:

[0051] (1) Preparation of silicone resin: Uniformly mix 16% of bifunctional phenyl vinyl silicone oil with a molecular weight of 7000 - 8000, 55% of trifunctional phenyl vinyl silicone resin with a molecular weight of 1000 - 1400, 28% of bifunctional phenyl hydrogen-containing silicone oil with a molecular weight of 300 - 400, 0.5% of PR1200 and 0.5% of inhibitor 3-methyl-1-pentyn-3-ol in a high-speed disperser.

[0052] (2) Preparation of Reinforcement 1: Uniformly disperse the silicone resin and nano-scale reinforcing filler according to the ratio using a three-roll mill to obtain Reinforcement 1;

[0053] (3) Preparation of Reinforcement 2: Add micron-scale reinforcing filler to Reinforcement 1 according to the ratio to obtain Reinforcement 2;

[0054] (4) Preparation of Component A of Ablation-resistant Coating: Add organic ablation-resistant filler to Reinforcement 2 according to the ratio to obtain Component A of the coating.

[0055] (5) Sample Preparation: Mix the obtained Component A of the coating and the curing agent evenly according to the ratio, add diluent for dilution, and then spray it on the surface of the polished substrate, and cure it at room temperature for more than 72 h to achieve the preparation of a 5.0 mm thick coating.

[0056] Example 2

[0057]

[0058] Among them, the silicone resin includes: 60% of trifunctional phenyl vinyl silicone resin with a molecular weight of 1000 - 1400, 37% of bifunctional phenyl hydrogen-containing silicone oil with a molecular weight of 200 - 300, 1.5% of Tego AddBond LT and 1.5% of inhibitor 3-methyl-1-pentyn-3-ol.

[0059] The white carbon black modified by hexamethyldisilazane is modified by high-temperature reflux method, and the contact angle after modification is 133.2°.

[0060] The modification method of KH550-modified high-silica fiber is ultrasonic pretreatment method, the ethanol solution concentration of the coupling agent is 10%, and the treatment time is 1 h.

[0061] (1) Preparation of silicone resin: 60% of trifunctional phenyl vinyl silicone resin with a molecular weight of 1000-1400, 37% of difunctional phenyl hydrogen silicone oil with a molecular weight of 200-300, 1.5% KH560 and 1.5% of inhibitor 3-methyl-1-pentyn-3-ol were uniformly mixed in a high-speed disperser.

[0062] (2) Preparation of reinforcement 1: Organic silicone resin and nano-scale reinforcing filler are uniformly dispersed using a three-roll mill according to the ratio to obtain reinforcement 1;

[0063] (3) Preparation of reinforcement 2: adding micron-sized reinforcing fillers to reinforcement 1 in proportion to obtain reinforcement 2;

[0064] (4) Preparation of component A of the ablation-resistant coating: Add ablation-resistant powder filler to the reinforcement 2 in proportion to obtain component A of the coating.

[0065] (5) Sample preparation: The obtained coating component A and curing agent were mixed evenly in proportion, diluted with diluent, and then sprayed on the polished substrate surface. The mixture was cured at room temperature for more than 72 hours to prepare a coating with a thickness of 5.0 mm.

[0066] Example 3

[0067]

[0068] The organic silicone resin includes 5% of a difunctional phenyl vinyl silicone oil with a molecular weight of 7000-8000, 56% of a trifunctional phenyl vinyl silicone resin with a molecular weight of 1200-1400, 38% of a difunctional phenyl hydrogen silicone oil with a molecular weight of 300-400, 0.5% of a tackifier adhesive promoter SK-Z04 and 0.5% of an inhibitor 3-methyl-1-butyn-3-ol.

[0069] Hexadimethyldisilazane-modified silica was modified by high-temperature reflux method, and the contact angle after modification was 133.2°.

[0070] The modification method of KH560 modified high silica fiber is ultrasonic pretreatment method, the concentration of the coupling agent ethanol solution is 15%, and the treatment time is 1h.

[0071] (1) Preparation of silicone resin: 5% of difunctional phenyl vinyl silicone oil with a molecular weight of 7000 - 8000, 56% of trifunctional phenyl vinyl silicone resin with a molecular weight of 1200 - 1400, 38% of difunctional phenyl hydrogen-containing silicone oil with a molecular weight of 300 - 400, 0.5% of Tackifier Adhesion promoter SK-Z04, and 0.5% of inhibitor 3-methyl-1-butyn-3-ol are uniformly mixed in a high-speed disperser.

[0072] (2) Preparation of Reinforcement 1: The silicone resin and nano-level reinforcing filler are uniformly dispersed using a three-roll mill according to the ratio to obtain Reinforcement 1;

[0073] (3) Preparation of Reinforcement 2: Micron-level reinforcing filler is added to Reinforcement 1 according to the ratio to obtain Reinforcement 2;

[0074] (4) Preparation of Component A of Ablation-resistant Coating: Ablation-resistant powder filler is added to Reinforcement 2 according to the ratio to obtain Component A of the coating.

[0075] (5) Sample Preparation: The obtained Component A of the coating and the curing agent are uniformly mixed according to the ratio, diluted with a diluent, and then sprayed on the surface of the polished substrate, and cured at room temperature for more than 72 h to prepare a coating with a thickness of 5.0 mm.

[0076] Comparative Example 1

[0077] This comparative example is the same as Example 1, except that: the coating formulation uses unmodified silica instead of silica modified with hexyldimethylsilazane.

[0078] Comparative Example 2

[0079] This comparative example is the same as Example 1, except that: the coating formulation uses unmodified high-silica fiber instead of high-silica fiber modified with KH570.

[0080] Comparative Example 3

[0081] This comparative example is the same as Example 1, except that: aramid powder is not added to the coating formulation.

[0082] Comparative Example 4

[0083] This comparative example is the same as Example 1, except that: the silicone resin does not contain trifunctional phenyl vinyl silicone resin, and the silicone resin includes: 16% of difunctional phenyl vinyl silicone oil with a molecular weight of 7000 - 8000, 83% of difunctional phenyl hydrogen-containing silicone oil with a molecular weight of 300 - 400, 0.5% of PR1200, and 0.5% of inhibitor 3-methyl-1-pentyn-3-ol.

[0084] The coating performance test results in Examples 1 to 3 are shown in Table 1 as follows:

[0085] The main indicators of the room-temperature curing type high-insulation ablation-resistant and heat-insulating coating of the present invention prepared according to Examples 1-3 are as follows in the table:

[0086] Table 1 Coating performance test results in Examples 1 to 3

[0087] Specific Parameters Example 1 Example 2 Example 3 <![CDATA[Density (g / cm 3 )]]> 0.90 0.85 0.80 Thermal Conductivity (50±5°C) (W / m·K) 0.13 0.11 0.12 Average Specific Heat Capacity (RT~100°C) (J / g·K) 1.40 1.35 1.34 Breakdown Field Strength (kV / mm) 22.5 17.4 16.8 <![CDATA[Ablation resistance (370 kW / m 2 ) Back temperature (°C)]]> 175 180 169

[0088] The effect diagram of the coating after wind tunnel assessment in Example 1 is shown in Figure 2 , the coating can pass the wind tunnel experiment assessment with a maximum of 370 kW / m 2 , and there is no peeling of the coating.

[0089] The coating performance test results in Comparative Examples 1 to 4 are shown in Table 2 as follows:

[0090] The main indicators of the room-temperature curing type high-insulation ablation-resistant and heat-insulating coating of the present invention prepared according to Comparative Examples 1 to 4 are as follows in the table:

[0091] Table 2 Coating performance test results in Comparative Examples 1 to 4

[0092]

[0093] The present invention has been described in detail above in combination with specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions of the present invention and their implementation manners, and these all fall within the scope of the present invention. The protection scope of the present invention is subject to the appended claims.

[0094] The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. A room-temperature curable high-insulation ablative heat-resistant coating, characterized in that, Comprising raw materials in the following parts by mass: Resin matrix: 100 parts; Nanoscale reinforcing filler: 15 - 30 parts; Micron-scale reinforcing filler: 10 - 20 parts; Organic ablation-resistant filler: 20 - 35 parts; Curing agent: 2 - 5 parts; The resin matrix is a phenyl addition-type silicone resin, including 0 - 20% of difunctional phenyl vinyl silicone oil with a molecular weight of 7000 - 10000, 40% - 60% of multifunctional phenyl vinyl silicone resin with a molecular weight of 1000 - 1500, 20% - 40% of difunctional phenyl hydrogen-containing silicone oil with a molecular weight of 200 - 400, 0.5% - 2% of adhesion promoter, and 0.1% - 1.0% of inhibitor; 2. The room-temperature curing type high-insulation ablation-resistant and heat-insulating coating according to claim 1, wherein The organic ablation-resistant filler is an aramid or polyetherimide powder filler with an electropositive benzene ring. The adhesion promoter is selected from at least one of PR1200, Tego AddBond LTW, Tackifier Adhesion promoterSK-Z04, KH560; and / or 3. The room-temperature curable high-insulation ablation-resistant and heat-insulating coating according to claim 1, wherein, The inhibitor is selected from at least one of 3-methyl-1-butyn-3-ol, 1-ethynyl-1-cyclohexanol, 3-methyl-1-pentyn-3-ol.

4. The room temperature curing type high insulation ablative resistant heat protection coating according to claim 1, characterized in that, The nanoscale reinforcing filler is surface-hydrophobically modified silica, and the modifier is hexamethyldisilazane.

5. The room-temperature curable high-insulation ablation-resistant and heat-insulating coating according to claim 1, wherein The micron-scale reinforcing filler is at least one of high silica fiber or quartz fiber, and the surface is modified with one of KH570, KH560 or KH550.

6. A room-temperature curable high-insulation ablation-resistant and heat-insulating coating, characterized in that, The curing agent is a platinum catalyst with a platinum content of 3000 ppm - 6000 ppm.

7. A preparation method of the room-temperature curing type high-insulation ablative-resistant and heat-insulating coating according to any one of claims 1 to 5, characterized in that, Prepared by using the room-temperature curable high-insulation ablation-resistant and heat-insulating coating according to any one of claims 1 to 5. Including: The resin matrix and the nanoscale reinforcing filler are uniformly dispersed according to the ratio to obtain Reinforcement 1; The micron-scale reinforcing filler is added to Reinforcement 1 according to the ratio to obtain Reinforcement 2; The organic ablation-resistant filler is added to Reinforcement 2 according to the ratio to obtain Component A of the coating; 8. A method for preparing a room-temperature curable high-insulation ablation-resistant and heat-insulating coating according to claim 6, characterized in that, Component A of the coating and the curing agent are mixed evenly according to the ratio, and after adding a diluent and diluting, a room-temperature curable high-insulation ablation-resistant and heat-insulating coating is prepared. Including: The room-temperature curable high-insulation ablation-resistant and heat-insulating coating is sprayed on the surface of the polished substrate, cured at room temperature for more than 72 h, or cured at 60 - 80 °C for more than 10 h after curing at room temperature for 12 - 24 h to obtain a coating.

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