3D-printed rubber thermal insulation material and method for producing the same

Abstract

The application provides a kind of 3D printing rubber heat-insulating material and its preparation method, the heat-insulating material includes base glue, anti-ablation filler, anti-ablation fiber, low-density filler, thixotropic agent, tackifier and curing agent;Each component is recorded by weight parts, and the composition is as follows:base glue: 100 parts;Anti-ablation filler: 10-30 parts;Anti-ablation fiber: 10-30 parts;Low-density filler: 1-10 parts;Thixotropic agent: 0.5-5 parts;Tackifier: 0.5-5 parts;Curing agent: 3-10 parts.The heat-insulating slurry prepared by the application is in liquid or paste form, can be extruded under low pressure 1-5 MPa conditions to realize 3D printing, with small extrusion difficulty and low equipment requirement;The synergistic effect of carbon-based, nitrogen-based and boron-based anti-ablation fillers forms a strong vitrified layer skeleton during the ablation process, which can effectively resist the scouring of high-temperature gas flow and particle flow of the engine, and improve the anti-ablation performance of the heat-insulating layer.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid rocket engine thermal insulation materials, and particularly relates to a 3D printing rubber thermal insulation material and a preparation method thereof. BACKGROUND

[0002] The inner thermal insulation layer is a thermal protection material located between the engine shell and the propellant, and its main function is to continuously decompose and ablate itself to carry away most of the heat, avoid the temperature of the shell being too high, and ensure the structural integrity of the shell and the normal work of the engine. At present, the inner thermal insulation layer is mainly made of nitrile rubber or ethylene-propylene-diene rubber, anti-ablation fillers, reinforcing fibers and functional additives, etc. After mixing and tabletting, it is pasted on the inner wall of the engine shell according to certain thickness requirements. The material is in the form of a tablet and cannot meet the requirements of the 3D printing process.

[0003] Patent No. CN202010323345.6 discloses a 3D printing system and method for the inner thermal insulation layer of a solid rocket engine, which uses light-activated liquid ethylene-propylene-diene rubber, nitrile rubber or liquid silicone rubber as the base material, and adopts micro-jet printing technology to form the thermal insulation layer. The molecular weight needs to be controlled within 3500-6500, and the viscosity needs to be controlled within 1000-6000 mPa·s to facilitate the 3D printing process of the thermal insulation layer. However, the low molecular weight of the thermal insulation material greatly limits the mechanical properties of the thermal insulation layer, making it difficult to meet the mechanical property requirements of the solid rocket engine. Moreover, the patent does not mention the key performance of the thermal insulation layer, i.e. the anti-ablation performance, which cannot be evaluated to determine whether it can meet the anti-ablation requirements of the engine. The article "Research Progress of 3D Printed Silicone Rubber" points out that the 3D printing of liquid rubber has the problem of difficulty in matching the curing speed and printing speed.

[0004] In the prior art, the traditional ethylene-propylene-diene rubber and nitrile rubber system patch thermal insulation material is in a solid form, which usually needs to be extruded at a high pressure of 20-50 MPa, making it difficult to be extruded for 3D printing and requiring high equipment. Moreover, the traditional ethylene-propylene-diene rubber and nitrile rubber system patch thermal insulation material cannot be cured and fused between layers under normal temperature and pressure, which cannot meet the requirements of the layer-by-layer 3D printing process. Although liquid ethylene-propylene-diene rubber, nitrile rubber or silicone rubber can meet the requirements of the 3D printing process, they still have problems such as insufficient mechanical properties and anti-ablation performance, and difficulty in matching the curing speed and printing speed. Therefore, the present application is proposed. SUMMARY

[0005] The present application aims to overcome the defects of the prior art and provides a 3D printing rubber thermal insulation material and a preparation method thereof.

[0006] The present application provides the following technical solutions:

[0007] This invention provides a 3D-printed rubber insulation material, comprising a base rubber, an ablation-resistant filler, an ablation-resistant fiber, a low-density filler, a thixotropic agent, a tackifier, and a curing agent; the components are listed in parts by weight as follows:

[0008] Base adhesive: 100 parts;

[0009] Anti-ablation filler: 10-30 parts;

[0010] Anti-ablation fiber: 10-30 parts;

[0011] Low-density filler: 1-10 parts;

[0012] Thixotropic agent: 0.5-5 parts;

[0013] Tackifier: 0.5-5 parts;

[0014] Hardener: 3-10 parts;

[0015] The viscosity of the base adhesive is 100,000 mPa·s to 1,000,000 mPa·s.

[0016] Furthermore, the base rubber includes one or more of methyl vinyl silicone rubber, phenyl vinyl silicone rubber, methyl vinyl silicone resin, phenyl vinyl silicone resin, methyl vinyl polysilazane resin, hydroxyl-terminated methyl silicone rubber, hydroxyl-terminated phenyl silicone rubber, and acrylate-modified silicone rubber.

[0017] Furthermore, the ablation-resistant filler includes one or more of the following: titanium carbide, titanium carbonitride, zirconium boride, zirconium nitride, zirconium oxide, silicon carbide, zirconium carbide, boron carbide, boron nitride, boron oxide, zirconium silicide, zirconium nitride, zirconium silicate, titanium boride, cerium diboride, molybdenum disilicide, silica, iron oxide, phenolic resin powder, benzoxazine resin powder, polyphenylene sulfide resin powder, polyimide resin powder, aramid resin powder, aramid fiber powder, polybenzoxazole fiber powder, cerium oxide, and silicone resin microspheres.

[0018] Furthermore, the ablation-resistant fiber includes one or more of the following: quartz fiber, high silica fiber, mullite fiber, zirconium oxide fiber, boron nitride fiber, alumina fiber, carbon fiber, phenolic fiber, aramid fiber, polyimide fiber, polybenzoxazole fiber, glass fiber, and basalt fiber.

[0019] Furthermore, the low-density filler includes one or more of the following: hollow glass microspheres, hollow ceramic microspheres, hollow silica microspheres, phenolic microspheres, aerogel powder, or cork powder.

[0020] Furthermore, the ablation-resistant filler, ablation-resistant fiber, and low-density filler are all surface-coated with high-temperature resistant resin; the high-temperature resistant resin includes one or more of polyboron silazane resin, polysilazane resin, methyl vinyl polysilazane resin, silicon zirconium inorganic resin, and silicon aluminum inorganic resin.

[0021] High-temperature resistant resin is used to coat the surfaces of ablation-resistant fillers, ablation-resistant fibers, and low-density fillers, improving the compatibility of the fillers, fibers, and base adhesive, and enhancing the mechanical properties of the insulation layer. The coated fillers and fibers form a robust ceramic-like skeleton during the ablation process, effectively resisting the erosion of high-temperature airflow and particle streams from the engine, thus improving the ablation resistance of the insulation layer.

[0022] Furthermore, the thixotropic agent comprises one or more of hydrophilic fumed silica, modified bentonite, and modified polyurethane.

[0023] Furthermore, the tackifier includes one or more of the following: borosilicate tackifiers, KH560, KH570, and KH171.

[0024] Furthermore, the curing agent includes one or more of the following: tetraethyl orthosilicate, dibutyltin dilaurate, stannous octoate, hydrogen-containing silicone oil, hydrogen-containing silicone resin, alkynyl alcohol inhibitor, polyvinylsiloxane inhibitor, platinum catalyst, and photoinitiator.

[0025] This invention also provides a method for preparing the above-mentioned 3D printed rubber insulation material, comprising the following steps:

[0026] S1. High-temperature resistant resin is sprayed onto the surfaces of the ablation-resistant filler, ablation-resistant fiber, and low-density filler. After spraying and stirring evenly, the mixture is dried at 150~250℃ and cooled to room temperature to obtain the surface-coated ablation-resistant filler, surface-coated ablation-resistant fiber, and surface-coated low-density filler. The mass ratio of the ablation-resistant filler, ablation-resistant fiber, and low-density filler to the high-temperature resistant resin is 100:5~20.

[0027] S2. Take the base adhesive, add the tackifier and the surface-coated ablation-resistant filler, knead for 10-20 minutes, continue to add the surface-coated ablation-resistant fiber and knead for 20-30 minutes, continue to add the surface-coated low-density filler and thixotropic agent and knead for 5-10 minutes; finally add the curing agent and knead for 5-10 minutes, while simultaneously vacuuming at -0.1MPa to remove bubbles, to obtain the 3D printing insulation slurry;

[0028] S3. The 3D printing insulation slurry is 3D printed and cured to obtain the 3D printed insulation material. The 3D printing adopts a layer-by-layer printing operation mode, and the curing is a combination of room temperature curing, heating curing, ultraviolet curing or microwave curing.

[0029] Using only room temperature curing results in slow curing speed, easy flow, and difficulty in maintaining shape, making it difficult to match curing speed with printing speed. Using only UV curing, heat curing, or microwave curing, although the curing speed is fast, can easily cause interlayer debonding problems when printing the next layer after full curing; printing the next layer after partial curing can cause uneven thermal curing of inner and outer layers, or even failure of inner layer thermal insulation to cure.

[0030] This invention employs room temperature curing (15~35℃, 6~24 hours), heat curing (60~150℃, 1~10 minutes), microwave curing (microwave frequency 2~3GHz, 30~120 seconds), and ultraviolet light curing (ultraviolet wavelength 365~405nm, power density 50~1000mW / cm²). 2 The process combines heating, UV curing, and microwave curing (with a curing time of 5-60 seconds) to quickly semi-cure and shape the insulation layer, preventing both the insulation layer from flowing and the layers from separating. After printing, the subsequent curing is completed at room temperature, solving the problem of mismatching the material curing speed and the printing speed.

[0031] The present invention has the following beneficial effects:

[0032] 1. This invention uses a liquid base adhesive with a viscosity of 100,000 mPa·s to 1,000,000 mPa·s. High-temperature resistant resin is used for surface coating of anti-ablation fillers, anti-ablation fibers, and low-density fillers, improving the compatibility of the fillers, fibers, and base adhesive. Through base adhesive viscosity control and filler / fiber surface coating treatment, a printing paste (liquid or paste form) with suitable viscosity is obtained, which can be extruded under pressure of 1-5 MPa for 3D printing. The extrusion process is simple and requires less equipment. Traditional processes use coupling agents to treat the fillers, requiring adjustment of the solution pH and precise control of the coupling agent hydrolysis rate, resulting in high process difficulty. This invention uses high-temperature resistant resin to treat the fillers, employing a simple spraying, stirring, and baking process, thus reducing process difficulty.

[0033] 2. This invention uses high-temperature resistant resin to coat the surface of anti-ablation fillers, anti-ablation fibers and low-density fillers, which improves the compatibility of fillers, fibers and base adhesives, and enhances the mechanical properties of the insulation layer (tensile strength, elongation at break and interlayer tear strength), thus meeting the mechanical performance requirements of insulation layer products.

[0034] 3. This invention utilizes the synergistic effect of boron-based, carbon-based, and nitrogen-based ablation-resistant fillers to obtain a heat insulation layer material with good ablation resistance. During the ablation process, the boron-based, carbon-based, and nitrogen-based fillers form a robust ceramic layer skeleton, which can effectively resist the erosion of high-temperature airflow and particle flow from the engine, thereby improving the ablation resistance of the heat insulation layer.

[0035] 4. This invention uses a combination of room temperature curing, heat curing, UV curing, and microwave curing to solve the problem of mismatch between curing speed and printing speed. First, the insulation layer is rapidly semi-cured and shaped by heat curing, UV curing, and microwave curing, which can prevent the insulation layer from flowing and debonding between layers, thus solving the problem of mismatch between curing speed and printing speed. After printing, subsequent curing is carried out at room temperature, which can achieve uniform curing degree of the inner and outer insulation layers, laying the foundation for realizing layer-by-layer 3D printing of the insulation layer. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a photograph of the 3D-printed rubber insulation material obtained in Example 1 of the present invention;

[0038] Figure 2 A photograph of the 3D-printed rubber insulation material prepared in Comparative Example 1 of this invention.

[0039] Figure 3 This is a photograph of the 3D-printed rubber insulation material obtained in Example 2 of the present invention;

[0040] Figure 4 A photograph of the 3D-printed rubber insulation material prepared in Comparative Example 2 of this invention.

[0041] Figure 5 This is a photograph of the 3D-printed rubber insulation material prepared in Example 3 of the present invention after oxyacetylene ablation.

[0042] Figure 6 This is a photograph of the 3D-printed rubber insulation material prepared in Comparative Example 3 of this invention after oxyacetylene ablation. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0044] In this embodiment, the 3D-printed rubber insulation material comprises the following components by weight:

[0045] Base rubber: 100 parts (80 parts phenyl vinyl silicone rubber, 20 parts methyl vinyl polysilazane resin, viscosity 500,000 mPa·s)

[0046] Anti-ablation filler: 20 parts (20 parts silicon carbide)

[0047] Ablation-resistant fiber: 10 parts (3 parts polyimide fiber, 7 parts carbon fiber)

[0048] Low-density filler: 5 parts (5 parts hollow ceramic microspheres)

[0049] Tackifier: 2 parts (1 part borosilicate tackifier, 1 part KH171)

[0050] Thixotropic agent: 3 parts (3 parts hydrophilic fumed silica)

[0051] Curing agent: 4.05 parts (containing 3 parts hydrogen silicone oil, 0.05 parts alkynol inhibitor, and 1 part platinum catalyst).

[0052] The specific process for preparing 3D printed rubber insulation materials is as follows:

[0053] 1. Add silicon carbide as an anti-ablation filler to a container. Weigh the silicon-zirconium inorganic resin according to the mass ratio of anti-ablation filler to silicon-zirconium inorganic resin = 100:10. Spray the silicon-zirconium inorganic resin onto the surface of the anti-ablation filler in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 500 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the surface-coated anti-ablation filler.

[0054] 2. Add the ablation-resistant polyimide fiber and carbon fiber to a container. Weigh the silicon zirconium inorganic resin according to the mass ratio of ablation-resistant fiber to silicon zirconium inorganic resin = 100:10. Spray the silicon zirconium inorganic resin onto the surface of the ablation-resistant fiber in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 300 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the surface-coated ablation-resistant fiber.

[0055] 3. Add the low-density filler hollow ceramic microspheres to the container. Weigh the silicon zirconium inorganic resin according to the mass ratio of hollow ceramic microspheres: silicon zirconium inorganic resin = 100:10. Spray the silicon zirconium inorganic resin onto the surface of the hollow ceramic microspheres in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 300 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the low-density filler with surface coating.

[0056] 4. Set the kneader speed to 100 r / min, add liquid silicone to the kneader, add 1 part of borosilicate tackifier, 1 part of KH171, and 20 parts of surface-coated silicon carbide, and knead for 10 minutes; then add 3 parts of surface-coated polyimide fiber and 7 parts of carbon fiber, and knead for 30 minutes; then add 5 parts of surface-coated hollow ceramic microspheres and 3 parts of hydrophilic fumed silica, and knead for 5 minutes; then add 3 parts of hydrogen-containing silicone oil, 0.05 parts of alkynol inhibitor, and 1 part of platinum catalyst, and knead for 10 minutes. At the same time, vacuum at -0.1 MPa to remove bubbles to obtain 3D printing insulation slurry.

[0057] 5. Place the 3D printing insulation slurry into the feeding hopper of the 3D printing system, set the 3D printing parameters, run the printing program to print the insulation layer (heating and pre-curing at 80℃ for 2 minutes during printing), and then cure at room temperature (25℃ for 12 hours) to obtain the 3D printed insulation material. Example 2

[0058] In this embodiment, the 3D-printed rubber insulation material comprises the following components by weight:

[0059] Base rubber: 100 parts (80 parts phenyl vinyl silicone rubber, 20 parts methyl vinyl polysilazane resin, viscosity 600,000 mPa·s)

[0060] Anti-ablation filler: 20 parts (20 parts silicon carbide)

[0061] Ablation-resistant fiber: 10 parts (3 parts polyimide fiber, 7 parts carbon fiber)

[0062] Low-density filler: 5 parts (5 parts hollow ceramic microspheres)

[0063] Tackifier: 2 parts (1 part borosilicate tackifier, 1 part KH171)

[0064] Thixotropic agent: 3 parts (3 parts hydrophilic fumed silica)

[0065] Curing agent: 4.05 parts (containing 3 parts hydrogen silicone oil, 0.05 parts alkynol inhibitor, and 1 part platinum catalyst).

[0066] The specific process for preparing 3D printed rubber insulation materials is as follows:

[0067] 1. Add silicon carbide as an anti-ablation filler to a container. Weigh the silicon-zirconium inorganic resin according to the mass ratio of anti-ablation filler to silicon-zirconium inorganic resin = 100:10. Spray the silicon-zirconium inorganic resin onto the surface of the anti-ablation filler in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 500 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the surface-coated anti-ablation filler.

[0068] 2. Add the ablation-resistant polyimide fiber and carbon fiber to a container. Weigh the silicon zirconium inorganic resin according to the mass ratio of ablation-resistant fiber to silicon zirconium inorganic resin = 100:10. Spray the silicon zirconium inorganic resin onto the surface of the ablation-resistant fiber in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 300 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the surface-coated ablation-resistant fiber.

[0069] 3. Add the low-density filler hollow ceramic microspheres to the container. Weigh the silicon zirconium inorganic resin according to the mass ratio of hollow ceramic microspheres: silicon zirconium inorganic resin = 100:10. Spray the silicon zirconium inorganic resin onto the surface of the hollow ceramic microspheres in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 300 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the low-density filler with surface coating.

[0070] 4. Set the kneader speed to 100 r / min, add liquid silicone to the kneader, add 1 part of borosilicate tackifier, 1 part of KH171, and 20 parts of surface-coated silicon carbide, and knead for 10 minutes; then add 3 parts of surface-coated polyimide fiber and 7 parts of carbon fiber, and knead for 30 minutes; then add 5 parts of surface-coated hollow ceramic microspheres and 3 parts of hydrophilic fumed silica, and knead for 5 minutes; then add 3 parts of hydrogen-containing silicone oil, 0.05 parts of alkynol inhibitor, and 1 part of platinum catalyst, and knead for 10 minutes. At the same time, vacuum at -0.1 MPa to remove bubbles to obtain 3D printing insulation slurry.

[0071] 5. Place the 3D printing insulation slurry into the feeding hopper of the 3D printing system, set the 3D printing parameters, run the printing program to print the insulation layer (heating and pre-curing at 80℃ for 2 minutes during printing), and then cure at room temperature (25℃ for 12 hours) to obtain the 3D printed insulation material. Example 3

[0072] In this embodiment, the 3D-printed rubber insulation material comprises the following components by weight:

[0073] Base rubber: 100 parts (80 parts phenyl vinyl silicone rubber, 20 parts methyl vinyl polysilazane resin, viscosity 500,000 mPa·s)

[0074] Ablation-resistant filler: 20 parts (5 parts silicon carbide, 10 parts zirconium nitride, 5 parts zirconium boride)

[0075] Ablation-resistant fiber: 10 parts (3 parts polyimide fiber, 7 parts carbon fiber)

[0076] Low-density filler: 5 parts (5 parts hollow ceramic microspheres)

[0077] Tackifier: 2 parts (1 part borosilicate tackifier, 1 part KH171)

[0078] Thixotropic agent: 3 parts (3 parts hydrophilic fumed silica)

[0079] Curing agent: 4.05 parts (containing 3 parts hydrogen silicone oil, 0.05 parts alkynol inhibitor, and 1 part platinum catalyst).

[0080] The specific process for preparing 3D printed rubber insulation materials is as follows:

[0081] 1. Add the ablation-resistant fillers silicon carbide, zirconium nitride, and zirconium boride to a container. Weigh the silicon-zirconium inorganic resin according to the mass ratio of ablation-resistant filler to silicon-zirconium inorganic resin = 100:10. Spray the silicon-zirconium inorganic resin onto the surface of the ablation-resistant filler in 5 applications. After each application, stir for 10 minutes using a disperser at a speed of 500 r / min. Finally, bake in an oven at 250℃ for 1 hour and cool to room temperature to obtain the surface-coated ablation-resistant filler.

[0082] 2. Add the ablation-resistant polyimide fiber and carbon fiber to a container. Weigh the silicon zirconium inorganic resin according to the mass ratio of ablation-resistant fiber to silicon zirconium inorganic resin = 100:10. Spray the silicon zirconium inorganic resin onto the surface of the ablation-resistant fiber in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 300 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the surface-coated ablation-resistant fiber.

[0083] 3. Add the low-density filler hollow ceramic microspheres to the container. Weigh the silicon zirconium inorganic resin according to the mass ratio of hollow ceramic microspheres: silicon zirconium inorganic resin = 100:10. Spray the silicon zirconium inorganic resin onto the surface of the hollow ceramic microspheres in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 300 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the low-density filler with surface coating.

[0084] 4. Set the kneader speed to 100 r / min, add liquid silicone to the kneader, add 1 part of silicon boron tackifier, 1 part of KH171, 5 parts of surface-coated silicon carbide, 10 parts of zirconium nitride, and 5 parts of zirconium boride, and knead for 10 minutes; then add 3 parts of surface-coated polyimide fiber and 7 parts of carbon fiber, and knead for 30 minutes; then add 5 parts of surface-coated hollow ceramic microspheres and 3 parts of hydrophilic fumed silica, and knead for 5 minutes; then add 3 parts of hydrogen-containing silicone oil, 0.05 parts of alkynol inhibitor, and 1 part of platinum catalyst, and knead for 10 minutes. At the same time, apply a vacuum of -0.1 MPa to remove bubbles to obtain the 3D printing insulation slurry.

[0085] 5. Place the 3D printing insulation slurry into the feeding hopper of the 3D printing system, set the 3D printing parameters, run the printing program to print the insulation layer (heating and pre-curing at 80℃ for 2 minutes during printing), and then cure at room temperature (25℃ for 12 hours) to obtain the 3D printed insulation material.

[0086] Comparative Example 1

[0087] In this embodiment, the 3D-printed rubber insulation material comprises the following components by weight:

[0088] Base rubber: 100 parts (80 parts phenyl vinyl silicone rubber, 20 parts methyl vinyl polysilazane resin, viscosity 500,000 mPa·s)

[0089] Anti-ablation filler: 20 parts (20 parts silicon carbide)

[0090] Ablation-resistant fiber: 10 parts (3 parts polyimide fiber, 7 parts carbon fiber)

[0091] Low-density filler: 5 parts (5 parts hollow ceramic microspheres)

[0092] Tackifier: 2 parts (1 part borosilicate tackifier, 1 part KH171)

[0093] Thixotropic agent: 3 parts (3 parts hydrophilic fumed silica)

[0094] Curing agent: 4.05 parts (containing 3 parts hydrogen silicone oil, 0.05 parts alkynol inhibitor, and 1 part platinum catalyst).

[0095] The specific process for preparing 3D printed rubber insulation materials is as follows:

[0096] 1. Set the kneader speed to 100 r / min, add liquid silicone to the kneader, add 1 part borosilicate tackifier, 1 part KH171, and 20 parts silicon carbide, and knead for 10 minutes; then add 3 parts polyimide fiber and 7 parts carbon fiber, and knead for 30 minutes; then add 5 parts hollow ceramic microspheres and 3 parts hydrophilic fumed silica, and knead for 5 minutes; then add 3 parts hydrogen-containing silicone oil, 0.05 parts alkynol inhibitor, and 1 part platinum catalyst, and knead for 10 minutes. At the same time, vacuum at -0.1 MPa to remove bubbles to obtain 3D printing insulation slurry.

[0097] 2. Place the 3D printing insulation paste into the feed hopper of the 3D printing system, set the 3D printing parameters, run the printing program to print the insulation layer (heating and pre-curing at 80℃ for 2 minutes during printing), and then cure at room temperature (25℃ for 12 hours) to obtain the 3D printed insulation material.

[0098] Comparative Example 2

[0099] In this embodiment, the 3D-printed rubber insulation material comprises the following components by weight:

[0100] Base rubber: 100 parts (80 parts phenyl vinyl silicone rubber, 20 parts methyl vinyl polysilazane resin, viscosity 600,000 mPa·s)

[0101] Anti-ablation filler: 20 parts (20 parts silicon carbide)

[0102] Ablation-resistant fiber: 10 parts (3 parts polyimide fiber, 7 parts carbon fiber)

[0103] Low-density filler: 5 parts (5 parts hollow ceramic microspheres)

[0104] Tackifier: 2 parts (1 part borosilicate tackifier, 1 part KH171)

[0105] Thixotropic agent: 3 parts (3 parts hydrophilic fumed silica)

[0106] Curing agent: 4.05 parts (containing 3 parts hydrogen silicone oil, 0.05 parts alkynol inhibitor, and 1 part platinum catalyst).

[0107] The specific process for preparing 3D printed rubber insulation materials is as follows:

[0108] 1. Add silicon carbide as an anti-ablation filler to a container. Weigh the silicon-zirconium inorganic resin according to the mass ratio of anti-ablation filler to silicon-zirconium inorganic resin = 100:10. Spray the silicon-zirconium inorganic resin onto the surface of the anti-ablation filler in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 500 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the surface-coated anti-ablation filler.

[0109] 2. Add the ablation-resistant polyimide fiber and carbon fiber to a container. Weigh the silicon zirconium inorganic resin according to the mass ratio of ablation-resistant fiber to silicon zirconium inorganic resin = 100:10. Spray the silicon zirconium inorganic resin onto the surface of the ablation-resistant fiber in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 300 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the surface-coated ablation-resistant fiber.

[0110] 3. Add the low-density filler hollow ceramic microspheres to the container. Weigh the silicon zirconium inorganic resin according to the mass ratio of hollow ceramic microspheres: silicon zirconium inorganic resin = 100:10. Spray the silicon zirconium inorganic resin onto the surface of the hollow ceramic microspheres in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 300 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the low-density filler with surface coating.

[0111] 4. Set the kneader speed to 100 r / min, add liquid silicone to the kneader, add 1 part of borosilicate tackifier, 1 part of KH171, and 20 parts of surface-coated silicon carbide, and knead for 10 minutes; then add 3 parts of surface-coated polyimide fiber and 7 parts of carbon fiber, and knead for 30 minutes; then add 5 parts of surface-coated hollow ceramic microspheres and 3 parts of hydrophilic fumed silica, and knead for 5 minutes; then add 3 parts of hydrogen-containing silicone oil, 0.05 parts of alkynol inhibitor, and 1 part of platinum catalyst, and knead for 10 minutes. At the same time, vacuum at -0.1 MPa to remove bubbles to obtain 3D printing insulation slurry.

[0112] 5. Place the 3D printing insulation slurry into the feeding hopper of the 3D printing system, set the 3D printing parameters, run the printing program to print the insulation layer, and cure at room temperature (25℃, 12h) to obtain the 3D printed insulation material.

[0113] Comparative Example 3

[0114] In this embodiment, the 3D-printed rubber insulation material comprises the following components by weight:

[0115] Base rubber: 100 parts (80 parts phenyl vinyl silicone rubber, 20 parts methyl vinyl polysilazane resin, viscosity 500,000 mPa·s)

[0116] Anti-ablation filler: 20 parts (20 parts zirconium nitride)

[0117] Ablation-resistant fiber: 10 parts (3 parts polyimide fiber, 7 parts carbon fiber)

[0118] Low-density filler: 5 parts (5 parts hollow ceramic microspheres)

[0119] Tackifier: 2 parts (1 part borosilicate tackifier, 1 part KH171)

[0120] Thixotropic agent: 3 parts (3 parts hydrophilic fumed silica)

[0121] Curing agent: 4.05 parts (containing 3 parts hydrogen silicone oil, 0.05 parts alkynol inhibitor, and 1 part platinum catalyst).

[0122] The specific process for preparing 3D printed rubber insulation materials is as follows:

[0123] 1. Add the ablation-resistant filler zirconium nitride to a container. Weigh the silicon zirconium inorganic resin according to the mass ratio of ablation-resistant filler to silicon zirconium inorganic resin = 100:10. Spray the silicon zirconium inorganic resin onto the surface of the ablation-resistant filler in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 500 r / min. Finally, place it in an oven at 250℃ for 1 hour and cool to room temperature to obtain the surface-coated ablation-resistant filler.

[0124] 2. Add the ablation-resistant polyimide fiber and carbon fiber to a container. Weigh the silicon zirconium inorganic resin according to the mass ratio of ablation-resistant fiber to silicon zirconium inorganic resin = 100:10. Spray the silicon zirconium inorganic resin onto the surface of the ablation-resistant fiber in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 300 r / min. Finally, place it in an oven and bake at 250℃ for 1 hour. Cool to room temperature to obtain the surface-coated ablation-resistant fiber.

[0125] 3. Add the low-density filler hollow ceramic microspheres to the container. Weigh the silicon zirconium inorganic resin according to the mass ratio of hollow ceramic microspheres: silicon zirconium inorganic resin = 100:10. Spray the silicon zirconium inorganic resin onto the surface of the hollow ceramic microspheres in 5 portions. After each spraying, stir for 10 minutes using a disperser at a speed of 300 r / min. Finally, place it in an oven and bake at 250℃ for 1 hour. Cool to room temperature to obtain the low-density filler with surface coating.

[0126] 4. Set the kneader speed to 100 r / min, add liquid silicone to the kneader, add 1 part of borosilicate tackifier, 1 part of KH171, and 20 parts of surface-coated zirconium nitride, and knead for 10 minutes; then add 3 parts of surface-coated polyimide fiber and 7 parts of carbon fiber, and knead for 30 minutes; then add 5 parts of surface-coated hollow ceramic microspheres and 3 parts of hydrophilic fumed silica, and knead for 5 minutes; then add 3 parts of hydrogen-containing silicone oil, 0.05 parts of alkynol inhibitor, and 1 part of platinum catalyst, and knead for 10 minutes. At the same time, vacuum at -0.1 MPa to remove bubbles to obtain 3D printing insulation slurry.

[0127] 5. Place the 3D printing insulation slurry into the feeding hopper of the 3D printing system, set the 3D printing parameters, run the printing program to print the insulation layer (heating and pre-curing at 80℃ for 2 minutes during printing), and then cure at room temperature (25℃ for 12 hours) to obtain the 3D printed insulation material.

[0128] The performance of the 3D printed thermal insulation materials prepared in Examples 1-3 and Comparative Examples 1-3 was analyzed and tested. The results are shown in Table 1.

[0129] Table 1 Performance test results of 3D printed thermal insulation materials

[0130]

[0131] As can be seen from the analysis of Example 1 and Comparative Example 1 (see photos) Figure 1 , Figure 2By selecting a base adhesive with appropriate viscosity and using high-temperature resistant resin to resist ablation fillers, as well as surface coating treatment of ablation-resistant fibers and low-density fillers, the compatibility of fillers, fibers, and base adhesives was improved, and the dispersion problem of fillers, fibers, and base adhesives was solved. The insulation slurry obtained a suitable viscosity and fluidity. The printed samples were dense and free of pores, and had good mechanical properties (tensile strength, elongation at break, and interlaminar tear strength) after curing. In contrast, in Comparative Example 1, the insulation slurry had poor fluidity, making printing difficult. The printed products had a large number of pore defects, and the ablation performance and mechanical properties were poor.

[0132] As can be seen from the analysis of Example 2 and Comparative Example 2 (see photos) Figure 3 , 4 This method combines room temperature curing and heat curing to solve the problem of matching curing speed with printing speed. First, heat curing is used to quickly semi-cur and shape the insulation layer, which can prevent the insulation layer from flowing and debonding between layers. After printing, room temperature curing is carried out to achieve uniform curing degree of the inner and outer insulation layers, laying the foundation for realizing layer-by-layer 3D printing of the insulation layer.

[0133] As can be seen from the analysis of Example 3 and Comparative Example 3 (see photos) Figure 5 , 6 In Comparative Example 3, carbon-based fillers, boron-based fillers, and nitrogen-based fillers form a synergistic effect, creating a robust ceramic layer skeleton during the ablation process. This effectively resists the erosion of the engine's high-temperature airflow and particle flow, improving the ablation resistance of the insulation layer. In Comparative Example 3, a single nitrogen-based filler cannot form a synergistic effect, and a robust ceramic layer skeleton is not formed after ablation. The surface ceramic layer has low strength and exhibits localized breakage.

[0134] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A 3D printed rubber thermal insulation material, characterized in that, The heat insulation material comprises base glue, anti-ablation filler, anti-ablation fiber, low-density filler, thixotropic agent, tackifier and curing agent; each component is recorded by weight parts, and the composition is as follows: Base glue: 100 parts; Anti-ablation filler: 10-30 parts; Anti-ablation fiber: 10-30 parts; Low-density filler: 1-10 parts; Thixotropic agent: 0.5-5 parts; Tackifier: 0.5-5 parts; Curing agent: 3-10 parts; The viscosity of the base glue is 100,000 mPa·s-1,000,000 mPa·s; The base glue comprises one or more of methyl vinyl silicone rubber, phenyl vinyl silicone rubber, methyl vinyl silicone resin, phenyl vinyl silicone resin, methyl vinyl polysilazane resin, hydroxyl-terminated methyl silicone rubber, hydroxyl-terminated phenyl silicone rubber, and acrylate-modified silicone rubber; The anti-ablation filler comprises zirconium boride, zirconium nitride and silicon carbide; The anti-ablation fiber comprises carbon fiber and polyimide fiber; The low-density filler comprises one or more of hollow glass microbeads, hollow ceramic microbeads, hollow silica microbeads, phenolic microspheres, aerogel powder or cork powder; The anti-ablation filler, anti-ablation fiber and low-density filler are all surface-coated with high-temperature-resistant resin; the high-temperature-resistant resin comprises silicon-zirconium inorganic resin.

2. The 3D-printed rubber thermal insulation material of claim 1, wherein: The thixotropic agent comprises one or more of hydrophilic fumed silica, modified bentonite and modified polyurethane.

3. The 3D-printed rubber thermal insulation material of claim 2, wherein: The tackifier comprises one or more of silicon-boron tackifier, KH560, KH570 and KH171.

4. The 3D-printed rubber thermal insulation material of claim 1, characterized by: The curing agent comprises one or more of tetraethyl orthosilicate, dibutyltin dilaurate, stannous octoate, hydrogen-containing silicone oil, hydrogen-containing silicone resin, acetylenic alcohol inhibitor, polyvinyl siloxane inhibitor, platinum gold catalyst and photoinitiator.

5. The method of producing a 3D-printed rubber thermal insulation material according to any one of claims 1 to 4, characterized in that, The preparation method comprises the following steps: S1. Spray high-temperature-resistant resin onto the surface of the anti-ablation filler, anti-ablation fiber and low-density filler, dry at 150-250°C after spraying and stirring evenly, and cool to room temperature to obtain the surface-coated anti-ablation filler, surface-coated anti-ablation fiber and surface-coated low-density filler; the mass ratio of the anti-ablation filler, anti-ablation fiber and low-density filler to the high-temperature-resistant resin is 100:5-20; S2. Add the base glue, tackifier and surface-coated anti-ablation filler to a kneader and knead for 10-20 min, continue to add the surface-coated anti-ablation fiber and knead for 20-30 min, continue to add the surface-coated low-density filler and thixotropic agent and knead for 5-10 min, and finally add the curing agent and knead for 5-10 min, while vacuuming at -0.1 MPa to remove bubbles, to obtain 3D printing heat insulation slurry; S3. 3D print the 3D printing heat insulation slurry, and obtain 3D printing heat insulation material after curing; the 3D printing adopts a layer-by-layer printing operation mode, and the curing is first fast semi-curing shaping of the heat insulation layer by heating curing, and then room temperature curing.

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