Quick-drying external heat-proof coating for solid rocket engine and preparation method of quick-drying external heat-proof coating

Abstract

The invention relates to the technical field of thermal protection materials, and particularly discloses a quick-drying external thermal protection coating for a solid rocket engine and a preparation method thereof.The coating comprises a component A and a component B. The component A comprises, by mass, 40-60 parts of isocyanate resin, 10-20 parts of high-temperature-resistant filler, 5-8 parts of modified phenolic resin, 1-2 parts of modified phenolic resin and 0.5-1 part of anti-settling agent; and the component B contains 50-60 parts of amino-terminated polyether, 15-20 parts of a chain extender, 10-20 parts of a high-temperature-resistant filler, 5-8 parts of modified phenolic resin and 0.5-1 part of an anti-settling agent. According to the quick-drying type external heat-proof coating for the solid rocket engine and the preparation method of the quick-drying type external heat-proof coating, the coating can be well bonded with a steel interface or a composite material interface, and the coating can be quickly cured in a room-temperature environment.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, and in particular to an external heat-resistant coating for a quick-drying solid rocket engine and a preparation method thereof. Background Art

[0002] At present, the country's demand for solid rocket engines is increasing day by day. The propellant charging plants are constantly under the rapidly increasing pressure of engine propellant charging, and the production process has put forward diverse, fast, efficient and high-quality spraying requirements for external heat protection materials.

[0003] The production of the charging plant starts with the welded engine casing entering the assembly line, and then goes through painting and assembly. The finished engine casing comes off the assembly line as a finished product. During the painting and assembly process, bumps and collisions are inevitable, and the coating will crack and peel off locally, exposing the sheet metal. To repair and restore the bumped parts, it is necessary to apply a layer of external heat protection on the engine casing. Although the existing external heat protection has qualified thermal performance, it cannot solve the problems of good bonding with composite materials and long curing cycle. When applying the external heat protection coating, it is still necessary to apply a topcoat, which increases the risk of interface debonding.

[0004] CN115028987A discloses a sprayable polyurethane ablation-resistant material formula, preparation method and application. The formula can be directly used to prepare the thermal insulation layer of a solid rocket engine by a sprayer, solving the problem of debonding caused by the weak interface bonding strength (steel shell) of the solid engine ablation-resistant material, and realizing the sprayable molding of the ablation-resistant material. However, if it is used for the outer heat-resistant coating (composite material shell) for a solid rocket engine, there are problems such as insufficient bonding strength, easy debonding, and fish-scale pattern phenomenon caused by the small atomization surface of the spray gun during the construction process, which forces the performance of the spray material to decline and does not meet the index requirements.

[0005] The purpose of the present invention is to overcome at least one of the defects of the above-mentioned prior art and to provide a solid rocket engine casing external heat protection and a preparation method thereof which has good bonding performance with steel interface and composite material interface and can be quickly cured in room temperature environment. Summary of the invention

[0006] The invention provides an external heat-resistant coating for a quick-drying solid rocket engine and a preparation method thereof. The coating can achieve good adhesion with a steel interface or a composite material interface and can also be quickly cured in a room temperature environment.

[0007] The technical solution of the present invention is to provide an external heat-resistant coating for a quick-drying solid rocket engine, comprising component A and component B, which are calculated by weight. Component A contains 40-60 parts of isocyanate resin, 10-20 parts of high temperature resistant filler, 5-8 parts of modified phenolic resin and 0.5-1 part of anti-settling agent; Component B contains 50-60 parts of amino-terminated polyether, 15-20 parts of chain extender, 10-20 parts of high temperature resistant filler, 5-8 parts of modified phenolic resin and 0.5-1 part of anti-settling agent.

[0008] Optionally, the isocyanate resin is one or more of aromatic isocyanate, aliphatic isocyanate and cycloaliphatic isocyanate.

[0009] Optionally, the amino-terminated polyether is one or more of polyethylene oxide diamine, polypropylene oxide diamine, and polypropylene oxide triamine. Optionally, the high temperature resistant filler is one or more of iron oxide, talc, mica, and silicon dioxide; and the average particle size of the high temperature resistant filler is 200 μm to 400 μm.

[0010] Optionally, the chain extender is one or more of ethylenediamine, triethylenetetramine, ethanolamine, and diethanolamine.

[0011] Optionally, the anti-settling agent is one or more of sodium dodecylbenzene sulfonate, polyvinyl alcohol, and castor oil derivatives.

[0012] Optionally, the modified phenolic resin uses thermoplastic phenolic resin as raw material, and NaOH solution and calcium chloride solution are added in sequence to react to obtain the modified phenolic resin. Specifically, the phenolic resin is first dispersed by adding water, and then the NaOH solution is added to react at 40-60° C. for 1-2 hours; after cooling, CaCl2 is added to mix, and then centrifugal filtration is performed to obtain the modified phenolic resin.

[0013] The present invention also relates to a method for preparing the outer heat-resistant coating, comprising the following steps: S1. Prepare component A and component B according to the ratio respectively; S2. Mix component A and component B and place them in a spraying device. Control the spraying pressure to 1500psi~2000psi, the spraying slurry temperature to 50℃~60℃, the spray gun nozzle diameter to 0.3mm~0.5mm, perform spraying, and finally solidify and shape.

[0014] Optionally, the curing molding temperature is 25°C~30°C, and the curing time is 48h~72h.

[0015] The present invention has the following beneficial effects: 1. The external heat shield prepared by spraying technology has the advantages of high interface bonding strength, high production efficiency and high dimensional accuracy. It can realize the continuous spraying production of solid engine external heat shield and improve the quality stability and reliability of the insulation layer.

[0016] 2. The external heat protection prepared by spraying technology has the advantages of fast surface drying and smooth surface. It can realize direct transportation and assembly after spraying of solid engine external heat protection, thus improving the production efficiency of engine external heat protection.

[0017] 3. The present invention uses modified phenolic resin as a solid phase filler and introduces ions to increase the bonding performance between the material and the steel interface and the composite material interface; and by adding modified phenolic resin, the catalytic polyurea reaction rate is accelerated and the spray molding efficiency is improved; in addition, the modified phenolic resin has very little effect on the viscosity of the slurry system, which is more conducive to spray construction. DETAILED DESCRIPTION

[0018] The experimental methods in the following examples are conventional methods unless otherwise specified. The raw materials, reagents, etc. used in the following examples are commercially available products unless otherwise specified.

[0019] A quick-drying solid rocket engine outer heat protection coating, comprising component A and component B, calculated by weight: Component A contains 40-60 parts of isocyanate resin, 10-20 parts of high temperature resistant filler, 5-8 parts of modified phenolic resin and 0.5-1 part of anti-settling agent; Component B contains 50-60 parts of amino-terminated polyether, 15-20 parts of chain extender, 10-20 parts of high temperature resistant filler, 1-2 parts of ablation resistant resin and 0.5-1 part of anti-settling agent.

[0020] In some embodiments, the isocyanate resin is one or more of aromatic isocyanate, aliphatic isocyanate and cycloaliphatic isocyanate.

[0021] In some embodiments, the amino-terminated polyether is one or more of polyethylene oxide diamine, polypropylene oxide diamine, and polypropylene oxide triamine. In some embodiments, the high temperature resistant filler is one or more of iron oxide, talc, mica, and silicon dioxide; and the average particle size of the high temperature resistant filler is 200 μm to 400 μm.

[0022] In some embodiments, the chain extender is one or more of ethylenediamine, triethylenetetramine, ethanolamine, and diethanolamine.

[0023] In some embodiments, the anti-settling agent is one or more of sodium dodecylbenzene sulfonate, polyvinyl alcohol, and castor oil derivatives.

[0024] In the following examples, the modified phenolic resin is self-made, and the thermoplastic phenolic resin is used as the raw material, and NaOH solution and calcium chloride solution are added in sequence to react to obtain the modified phenolic resin. Specifically, the phenolic resin is first dispersed by adding water, and then the NaOH solution is added and reacted at 50°C for 1h; after cooling, CaCl2 is added and mixed, stirred at room temperature for 1h, and then centrifuged to obtain the modified phenolic resin.

[0025] The specific preparation of the external heat-resistant coating includes the following steps: S1, prepare component A and component B respectively according to the ratio; when preparing component A, add high temperature resistant filler, modified phenolic resin, anti-settling agent and other additives to isocyanate resin and mix them evenly; when preparing component B, add high temperature resistant filler, chain extender, modified phenolic resin, anti-settling agent and other additives to amino-terminated polyether and mix them evenly; S2. Mix component A and component B and place them in the barrel of the spray equipment. Control the spraying pressure to 1500psi~2000psi, the spray slurry temperature to 50℃~60℃, the spray gun nozzle diameter to 0.3mm~0.5mm, and use a pressure pump to transport the slurry to the spray gun mixing chamber for spraying to make external heat protection material. Finally, cure it at 25℃~30℃ for 48h~72h to form it.

[0026] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0027] Embodiment 1: Weigh 40 parts of aromatic isocyanate, 10 parts of iron oxide, 5 parts of modified phenolic resin, and 0.5 parts of sodium dodecylbenzene sulfonate, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment A; weigh 50 parts of polyethylene oxide, 10 parts of talc, 15 parts of ethylenediamine, 5 parts of modified phenolic resin, and 0.5 parts of sodium dodecylbenzene sulfonate, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment B, set the spraying pressure to 1500psi, the spraying temperature to 50°C, the nozzle diameter to 0.3mm, use cross-cross reciprocating spraying for multiple times, and the bottom layer spray outer heat protection thickness is 0.2mm.

[0028] The spray-coated erosion-resistant thermal insulation material was placed at room temperature for curing for 48 hours, and the tensile strength, elongation at break, peel strength with the engine casing, and peel strength with the composite material were tested.

[0029] Embodiment 2: Weigh 50 parts of aromatic isocyanate, 15 parts of talc, 6 parts of modified phenolic resin, and 0.5 parts of polyvinyl alcohol, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment A; weigh 50 parts of polypropylene oxide diamine, 10 parts of mica, 15 parts of ethylenediamine, 6 parts of modified phenolic resin, and 0.5 parts of polyvinyl alcohol, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment B, set the spraying pressure to 1600psi, the spraying temperature to 55°C, the nozzle diameter to 0.4mm, use cross-cross reciprocating spraying for multiple times, and the bottom layer spray has an outer heat protection thickness of 0.4mm.

[0030] The spray-coated erosion-resistant thermal insulation material was cured at room temperature for 60 hours, and the tensile strength, elongation at break, peel strength with the engine casing, and peel strength with the composite material were tested.

[0031] Embodiment 3: Weigh 50 parts of aliphatic isocyanate, 15 parts of talc, 7 parts of modified phenolic resin, and 1 part of polyvinyl alcohol, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment A; weigh 60 parts of polypropylene oxide triamine, 10 parts of mica, 20 parts of diethanolamine, 7 parts of modified phenolic resin, and 0.5 parts of polyvinyl alcohol, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment B, set the spraying pressure to 1800psi, the spraying temperature to 55°C, the nozzle diameter to 0.5mm, use cross-cross reciprocating spraying for multiple times, and the bottom layer spray has an outer heat protection thickness of 0.6mm.

[0032] The spray-coated erosion-resistant thermal insulation material was cured at room temperature for 60 hours, and the tensile strength, elongation at break, peel strength with the engine casing, and peel strength with the composite material were tested.

[0033] Embodiment 4: Weigh 50 parts of cycloaliphatic isocyanate, 15 parts of silica, 8 parts of modified phenolic resin, and 1 part of polyvinyl alcohol, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment A; weigh 55 parts of polypropylene oxide triamine, 10 parts of silica, 15 parts of ethanolamine, 8 parts of modified phenolic resin, and 0.5 parts of polyvinyl alcohol, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment B, set the spraying pressure to 2000psi, the spraying temperature to 60°C, the nozzle diameter to 0.5mm, use cross-cross reciprocating spraying for multiple times, and the bottom layer spray outer heat protection thickness is 0.6mm.

[0034] The spray-coated erosion-resistant thermal insulation material was cured at room temperature for 72 hours, and the tensile strength, elongation at break, peel strength with the engine casing, and peel strength with the composite material were tested.

[0035] Embodiment 5: Weigh 50 parts of cycloaliphatic isocyanate, 15 parts of silica, and 1 part of polyvinyl alcohol, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment A; weigh 55 parts of polypropylene oxide triamine, 10 parts of silica, 15 parts of ethanolamine, and 0.5 parts of polyvinyl alcohol, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment B, set the spraying pressure to 2000psi, the spraying temperature to 60°C, the nozzle diameter to 0.5mm, use cross-cross reciprocating spraying for multiple times, and the bottom layer spray outer heat protection thickness is 0.6mm.

[0036] The spray-coated erosion-resistant thermal insulation material was cured at room temperature for 72 hours, and the tensile strength, elongation at break, peel strength with the engine casing, and peel strength with the composite material were tested.

[0037] Embodiment 6: Weigh 50 parts of cycloaliphatic isocyanate, 15 parts of silica, 8 parts of thermoplastic phenolic resin, and 1 part of polyvinyl alcohol, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment A; weigh 55 parts of polypropylene oxide triamine, 10 parts of silica, 15 parts of ethanolamine, 8 parts of thermoplastic phenolic resin, and 0.5 parts of polyvinyl alcohol, stir and mix evenly, and place the mixed spray slurry in the barrel of spray equipment B, set the spraying pressure to 2000psi, the spraying temperature to 60°C, the nozzle diameter to 0.5mm, use cross-cross reciprocating spraying for multiple times, and the bottom layer spray has an outer heat protection thickness of 0.6mm.

[0038] The spray-coated erosion-resistant thermal insulation material was cured at room temperature for 72 hours, and the tensile strength, elongation at break, peel strength with the engine casing, and peel strength with the composite material were tested.

[0039] The test conditions for the tensile strength, elongation at break, surface drying time, peel strength with engine steel casing, and peel strength with composite materials of the spray-coated external heat protection materials of the above embodiments and comparative examples are shown in Table 1, and the test results are shown in Table 2.

[0040] Table 1 Test standards and methods

[0041] Table 2 Test results

[0042] As can be seen from Table 2, when modified phenolic resin is not added in Example 5, material mechanical properties and steel interface bonding properties do not have detailed changes, but it and composite material bonding properties decline, and the surface drying time also increases. When using modified phenolic resin precursor thermoplastic novolac resin, material mechanical properties and steel interface bonding properties are almost unchanged, but it and composite material bonding properties decline, and the surface drying time also increases. The modified phenolic resin improved by the present invention also shortens its surface drying time while increasing and composite material interface bonding strength, and provides a solution for the continuous and automated spraying of solid rocket motor exothermic materials.

[0043] The above embodiments describe the preferred implementation of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A quick-drying solid rocket engine outer heat protection coating, characterized in that: Including component A and component B, by mass: Component A contains 40-60 parts of isocyanate resin, 10-20 parts of high temperature resistant filler, 5-8 parts of modified phenolic resin and 0.5-1 part of anti-settling agent; Component B contains 50-60 parts of amino-terminated polyether, 15-20 parts of chain extender, 10-20 parts of high temperature resistant filler, 5-8 parts of modified phenolic resin and 0.5-1 part of anti-settling agent.

2. The outer heat protection coating according to claim 1, characterized in that: The isocyanate resin is one or more of aromatic isocyanate, aliphatic isocyanate and cycloaliphatic isocyanate.

3. The outer heat protection coating according to claim 1, characterized in that: The amino-terminated polyether is one or more of polyethylene oxide diamine, polypropylene oxide diamine and polypropylene oxide triamine.

4. The outer heat protection coating according to claim 1, characterized in that: The high temperature resistant filler is one or more of iron oxide, talc, mica and silicon dioxide; the average particle size of the high temperature resistant filler is 200 μm-400 μm.

5. The outer heat protection coating according to claim 1, characterized in that: The chain extender is one or more of ethylenediamine, triethylenetetramine, ethanolamine and diethanolamine.

6. The outer heat protection coating according to claim 1, characterized in that: The anti-settling agent is one or more of sodium dodecylbenzene sulfonate, polyvinyl alcohol, and castor oil derivatives.

7. The outer heat protection coating according to any one of claims 1 to 6, characterized in that: The modified phenolic resin uses thermoplastic phenolic resin as raw material, and NaOH solution and calcium chloride solution are added in sequence to react to obtain the modified phenolic resin.

8. The outer heat protection coating according to claim 7, characterized in that: The phenolic resin is first dispersed by adding water, and then NaOH solution is added to react at 40-60°C for 1-2 hours; after cooling, CaCl2 is added to mix, and then centrifugal filtration is performed to obtain the modified phenolic resin.

9. The method for preparing the outer heat-resistant coating according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Prepare component A and component B according to the ratio respectively; S2. Mix component A and component B and place them in a spraying device. Control the spraying pressure to 1500psi~2000psi, the spraying slurry temperature to 50℃~60℃, the spray gun nozzle diameter to 0.3mm~0.5mm, perform spraying, and finally solidify and shape.

10. The preparation method according to claim 9, characterized in that: The curing temperature is 25℃~30℃, and the curing time is 48h~72h.

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