Low-temperature curing high-softening-temperature ablation-resistant resin coating layer material and preparation method thereof

Abstract

The invention relates to the technical field of ablation-resistant resin materials, in particular to a low-temperature curing high-softening-temperature ablation-resistant resin coating layer material and a preparation method thereof.The low-temperature curing high-softening-temperature ablation-resistant resin coating layer material is prepared from, by weight, 60-70 parts of butyl methacrylate prepolymer liquid, 20-30 parts of silicon monomers, 5-15 parts of ablation-resistant filler, 0-1 part of accelerant and 0-2 parts of initiator; wherein the accelerant and the initiator are not 0, and the butyl methacrylate prepolymer solution is prepared by dissolving polybutyl methacrylate in a butyl methacrylate monomer. Based on the good heat resistance of a silicon group and the high bond energy characteristic of a Si-O-Si bond, the softening temperature and ablation resistance of a polybutyl methacrylate coating layer material are optimized by regulating and controlling the type and dosage of a silicon monomer; and the curing temperature of the polybutyl methacrylate coating layer material is reduced by regulating and controlling the types and the use amounts of the accelerant and the initiator.

Description

Technical Field

[0001] The invention relates to the technical field of ablation-resistant resin materials, and in particular to a low-temperature curing and high-softening-temperature ablation-resistant resin coating layer material and a preparation method thereof. Background Art

[0002] Propellant coating materials play a vital role in solid motors and ammunition. During use, the coating materials must have sufficient mechanical strength to prevent cracking and damage under stress. Polybutyl methacrylate has a long ester carbon chain and good flexibility. Its monomer has high tensile strength and impact strength, and can form a good bond with gunpowder, making it a good low-smoke coating material. However, polybutyl methacrylate has poor ablation resistance and will not stop burning in the air. In addition, polybutyl methacrylate has a low softening temperature and a high curing temperature. When using the traditional high-temperature curing process, the coating will produce strong thermal stress during the cooling process, which may cause the coating to debond with the propellant grain, thereby affecting the mechanical and combustion properties of the propellant. In addition, the high-temperature curing process will increase the danger in the propellant production process and is not conducive to coping with different combat environments. This greatly limits the use of polybutyl methacrylate coating materials.

[0003] Silicon-containing groups have high thermal stability, oxidation stability, and good flexibility, which can be used to improve the low softening temperature of polybutyl methacrylate coating materials, and can make the obtained polybutyl methacrylate coating materials fully crosslinked and cured at low temperatures. On the other hand, the influence of high-performance ablation-resistant fillers and suitable curing systems on the performance of coating materials is also crucial. Because evenly dispersed fillers can form a strong binding force with the resin matrix, thereby pinning the resin molecules, and ultimately improving the mechanical properties and softening temperature of the coating material, and selecting the appropriate type and amount of accelerators and initiators as the curing system can effectively reduce the curing temperature of the polybutyl methacrylate coating material, so that the obtained coating material has a broader application prospect. Summary of the invention

[0004] In order to improve the problem of low softening temperature of polybutyl methacrylate coating layer material, the present invention provides a low-temperature curing high-softening-temperature ablation-resistant resin coating layer material and a preparation method thereof.

[0005] The present invention is realized through the following technical scheme: a low-temperature curing and high-softening-temperature ablation-resistant resin coating material is prepared from the following raw materials in the following weight proportions: 60 to 70 parts of butyl methacrylate prepolymer liquid, 20 to 30 parts of silicon monomer, 5 to 15 parts of ablation-resistant filler, 0 to 1 part of accelerator, and 0 to 2 parts of initiator; wherein the accelerator and the initiator are not 0, and the butyl methacrylate prepolymer liquid is prepared by dissolving polybutyl methacrylate in butyl methacrylate monomer.

[0006] As a further improvement of the technical solution of the present invention, the mass concentration of polybutyl methacrylate in the butyl methacrylate prepolymer solution is 5-20%.

[0007] As a further improvement of the technical solution of the present invention, the silicon monomer is two or more of γ-aminopropyltriethoxysilane, vinyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and methacryloxypropylmethyldimethoxysilane.

[0008] As a further improvement of the technical solution of the present invention, the ablation-resistant filler is one or more of mica powder, zirconium oxide, aluminum hydroxide and titanium dioxide.

[0009] As a further improvement of the technical solution of the present invention, the accelerator is one or more of vinyltriamine, m-phenylenediamine, diaminodiphenylmethane and N,N-dimethylaniline.

[0010] As a further improvement of the technical solution of the present invention, the initiator is one or more of benzoyl peroxide, azobisisobutyronitrile, ammonium persulfate and dimethyl azobisisobutyrate.

[0011] The present invention further provides a method for preparing a low-temperature curing and high-softening-temperature ablation-resistant resin coating material, comprising the following steps:

[0012] (1) Blending of resin matrix and filler: First, butyl methacrylate prepolymer liquid, silicon monomer and ablation-resistant filler are stirred and mixed at room temperature, then accelerator and initiator are added and stirred and mixed, and then vacuum degassing is performed to obtain prepolymer slurry;

[0013] (2) Curing of the resin coating material: After step (1) is completed, the preheated mold is taken out and the prepolymer slurry is poured into the mold. The mold is then placed in an oven to activate the prepolymer slurry in the mold. The mold is then cured at a constant temperature and removed from the mold to obtain a low-temperature cured, high-softening-temperature, ablation-resistant resin coating material.

[0014] As a further improvement of the technical solution of the method of the present invention, in step (1), the rotation speed of stirring and mixing is 300-500 r / min, and the time of vacuum degassing is 20-40 min.

[0015] As a further improvement of the technical solution of the method of the present invention, in step (2), the activation temperature of the prepolymer slurry is 40 to 50° C., and the activation time is 20 to 50 min.

[0016] As a further improvement of the technical solution of the method of the present invention, in step (2), the curing temperature is 40 to 50° C. and the curing time is 24 to 48 hours.

[0017] The low-temperature curing and high-softening-temperature ablation-resistant resin coating material and the preparation method thereof provided by the present invention have the following advantages compared with the prior art:

[0018] First, the present invention optimizes the softening temperature and ablation resistance of the polybutyl methacrylate coating material by regulating the type and amount of silicon monomers. Based on the good heat resistance of the silicon group and the high bond energy of the Si-O-Si bond, the coating material exhibits more excellent softening temperature and ablation resistance.

[0019] Second, the present invention optimizes the type and filling amount of the ablation-resistant filler to form a strong and uniform filler-resin three-dimensional network structure, so that the coating layer material can further improve the ablation resistance on the basis of showing more excellent mechanical properties.

[0020] Third, based on the modification of the resin matrix and the synergistic reinforcement of the filler, the present invention selects suitable promoters and initiators and explores their appropriate addition amounts, so that the prepared ablation-resistant resin coating material can achieve sufficient curing and crosslinking under low temperature conditions while obtaining excellent comprehensive performance. DETAILED DESCRIPTION

[0021] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0023] The present invention provides a specific embodiment of a low-temperature curing and high-softening-temperature ablation-resistant resin coating material, which is prepared from the following raw materials in the following weight proportions: 60 to 70 parts of butyl methacrylate prepolymer liquid, 20 to 30 parts of silicon monomer, 5 to 15 parts of ablation-resistant filler, 0 to 1 part of accelerator, and 0 to 2 parts of initiator; wherein the accelerator and the initiator are not 0, and the butyl methacrylate prepolymer liquid is prepared by dissolving polybutyl methacrylate in butyl methacrylate monomer.

[0024] In one embodiment provided by the present invention, the mass concentration of polybutyl methacrylate in the butyl methacrylate prepolymer solution is 5-20%.

[0025] In another embodiment provided by the present invention, the silicon monomer is two or more of γ-aminopropyl triethoxysilane (KH550), vinyl triethoxysilane, γ-glycidyloxypropyl trimethoxysilane, γ-methacryloxypropyl trimethoxysilane (KH570) and methacryloxypropyl methyl dimethoxysilane. In the present invention, two or more silicon monomers are used because the differences in the structures of the various silicon monomers can make them show different activities and cross-linking abilities in the copolymerization reaction, thereby producing complementary effects in improving the material properties.

[0026] In one embodiment provided by the present invention, the ablation-resistant filler is one or more of mica powder, zirconium oxide, aluminum hydroxide and titanium dioxide. Compared with other ablation-resistant fillers, aluminum hydroxide absorbs heat and dehydrates during heating, which helps to reduce the temperature of the material system, thereby slowing down the thermal degradation rate and improving the thermal stability and flame retardant properties of the material.

[0027] In another embodiment provided by the present invention, the accelerator is one or more of vinyltriamine, m-phenylenediamine, diaminodiphenylmethane and N,N-dimethylaniline.

[0028] In one embodiment provided by the present invention, the initiator is one or more of benzoyl peroxide, azobisisobutyronitrile, ammonium persulfate and dimethyl azobisisobutyrate.

[0029] The present invention also provides a method for preparing the above-mentioned low-temperature curing and high-softening-temperature ablation-resistant resin coating material, comprising the following steps:

[0030] (1) Blending of resin matrix and filler: First, butyl methacrylate prepolymer liquid, silicon monomer and ablation-resistant filler are stirred and mixed at room temperature, then accelerator and initiator are added and stirred and mixed, and then vacuum degassing is performed to obtain prepolymer slurry;

[0031] (2) Curing of the resin coating material: After step (1) is completed, the preheated mold is taken out and the prepolymer slurry is poured into the mold. The mold is then placed in an oven to activate the prepolymer slurry in the mold. The mold is then cured at a constant temperature and removed from the mold to obtain a low-temperature cured, high-softening-temperature, ablation-resistant resin coating material.

[0032] Preferably, in step (1), the stirring and mixing speed is 300-500 r / min, and the vacuum degassing time is 20-40 min.

[0033] Further preferably, in step (2), the activation temperature of the prepolymer slurry is 40 to 50° C., and the activation time is 20 to 50 min.

[0034] Further preferably, in step (2), the curing temperature is 40 to 50° C. and the curing time is 24 to 48 hours.

[0035] The specific embodiments of the present invention are described in detail below.

[0036] In the present invention, unless otherwise specified, the raw materials used are all commercially available products in the art.

[0037] Example 1

[0038] A low-temperature curing, high-softening-temperature ablation-resistant resin coating material is prepared from the following raw materials in the following weight proportions: 65 parts of butyl methacrylate prepolymer liquid, 15 parts of KH570, 10 parts of KH550, 10 parts of aluminum hydroxide, 0.1 parts of N,N-dimethylaniline, and 0.2 parts of benzoyl peroxide. The preparation method comprises the following steps: firstly, the butyl methacrylate prepolymer liquid, silicon monomer and aluminum hydroxide are stirred and mixed at room temperature and 400r / min for 20 minutes, then the accelerator and initiator are added and stirred and mixed at room temperature and 400r / min for 20 minutes, after stirring, vacuum degassing for 30 minutes to obtain a prepolymer slurry, then taking out the preheated mold and pouring the prepolymer slurry into it, and then putting it into a 45°C oven to activate the prepolymer slurry in the mold for 50 minutes. Then, it is cured at a constant temperature of 40°C for 36 hours, and then it is taken out and demolded to obtain a high-performance ablation-resistant resin coating material.

[0039] The mass concentration of polybutyl methacrylate in the butyl methacrylate prepolymer solution is 10%. The concentration of the butyl methacrylate prepolymer solution is the same as that in each embodiment and comparative example.

[0040] Example 2

[0041] A low-temperature curing, high-softening-temperature ablation-resistant resin coating material is prepared from the following raw materials in the following weight proportions: 65 parts of butyl methacrylate prepolymer liquid, 15 parts of KH570, 10 parts of KH550, 10 parts of mica powder, 0.1 parts of N,N-dimethylaniline, and 0.2 parts of benzoyl peroxide. The preparation method comprises the following steps: firstly, the butyl methacrylate prepolymer liquid, silicon monomer and mica powder are stirred and mixed at room temperature and 400r / min for 20 minutes, then the accelerator and initiator are added and stirred and mixed at room temperature and 400r / min for 20 minutes, after stirring, vacuum degassing for 30 minutes to obtain a prepolymer slurry, then taking out the preheated mold and pouring the prepolymer slurry into it, and then putting it into a 45°C oven to activate the prepolymer slurry in the mold for 50 minutes. Then, it is cured at a constant temperature of 40°C for 36 hours, and then it is taken out and demolded to obtain a high-performance ablation-resistant resin coating material.

[0042] Comparative Example 1

[0043] A resin coating material is prepared from the following raw materials in the following weight proportions: 65 parts of butyl methacrylate prepolymer liquid, 25 parts of KH570, 10 parts of aluminum hydroxide, 0.1 parts of N,N-dimethylaniline, and 0.2 parts of benzoyl peroxide. The preparation method comprises the following steps: firstly, the butyl methacrylate prepolymer liquid, silicon monomer and aluminum hydroxide are stirred and mixed at room temperature and 400r / min for 20 minutes, then a promoter and an initiator are added and stirred and mixed at room temperature and 400r / min for 20 minutes, after stirring, vacuum degassing for 30 minutes to obtain a prepolymer slurry, then taking out the preheated mold and pouring the prepolymer slurry into it, and then putting it into a 45°C oven to activate the prepolymer slurry in the mold for 50 minutes. Then, it is cured at a constant temperature of 40°C for 36 hours, and then it is taken out and demolded to obtain the resin coating material.

[0044] Comparative Example 2

[0045] A resin coating material is prepared from the following raw materials in the following weight proportions: 65 parts of butyl methacrylate prepolymer liquid, 25 parts of KH550, 10 parts of aluminum hydroxide, 0.1 parts of N,N-dimethylaniline, and 0.2 parts of benzoyl peroxide. The preparation method comprises the following steps: firstly, the butyl methacrylate prepolymer liquid, silicon monomer and aluminum hydroxide are stirred and mixed at room temperature and 400r / min for 20 minutes, then a promoter and an initiator are added and stirred and mixed at room temperature and 400r / min for 20 minutes, after stirring, vacuum degassing for 30 minutes to obtain a prepolymer slurry, then taking out the preheated mold and pouring the prepolymer slurry into it, and then putting it into a 45°C oven to activate the prepolymer slurry in the mold, and the activation time is 50 minutes. Then, it is cured at a constant temperature of 40°C for 36 hours, and then it is taken out and demolded to obtain the resin coating material.

[0046] Comparative Example 3

[0047] A resin coating material is prepared from the following raw materials in the following weight proportions: 65 parts of butyl methacrylate prepolymer liquid, 10 parts of aluminum hydroxide, 0.1 parts of N,N-dimethylaniline, and 0.2 parts of benzoyl peroxide. The preparation method comprises the following steps: firstly, the butyl methacrylate prepolymer liquid and aluminum hydroxide are stirred and mixed at room temperature and 400r / min for 20 minutes, then a promoter and an initiator are added and stirred and mixed at room temperature and 400r / min for 20 minutes, after stirring, vacuum degassing for 30 minutes to obtain a prepolymer slurry, then taking out the preheated mold and pouring the prepolymer slurry into it, and then putting it into a 50°C oven to activate the prepolymer slurry in the mold, and the activation time is 50 minutes. Then, it is cured at a constant temperature of 45°C for 36 hours, and then it is taken out and demolded to obtain the resin coating material.

[0048] Comparative Example 4

[0049] A resin coating material is prepared from the following raw materials in the following weight proportions: 65 parts of styrene prepolymer liquid, 15 parts of KH570, 10 parts of KH550, 10 parts of aluminum hydroxide, 0.1 parts of N,N-dimethylaniline, and 0.2 parts of benzoyl peroxide. The preparation method comprises the following steps: firstly, the styrene prepolymer liquid, silicon monomer and aluminum hydroxide are stirred and mixed at room temperature and 400r / min for 20min, then a promoter and an initiator are added and stirred and mixed at room temperature and 400r / min for 20min, after stirring, vacuum degassing for 30min to obtain a prepolymer slurry, then taking out the preheated mold and pouring the prepolymer slurry into it, and then putting it into a 70°C oven to activate the prepolymer slurry in the mold, and the activation time is 50min. Then, it is cured at a constant temperature of 65°C for 36h, and then it is taken out and demolded to obtain the resin coating material.

[0050] Comparative Example 5

[0051] A low-temperature curing, high-softening-temperature, ablation-resistant resin coating material is prepared from the following raw materials in the following weight proportions: 65 parts of butyl methacrylate prepolymer liquid, 25 parts of isooctyl methacrylate monomer, 10 parts of aluminum hydroxide, 0.1 parts of N,N-dimethylaniline, and 0.2 parts of benzoyl peroxide. The preparation method comprises the following steps: firstly, the butyl methacrylate prepolymer liquid, 25 parts of isooctyl methacrylate monomer, and aluminum hydroxide are stirred and mixed at room temperature and 400r / min for 20 minutes, then a promoter and an initiator are added, and stirred and mixed at room temperature and 400r / min for 20 minutes, after stirring, vacuum degassing for 30 minutes to obtain a prepolymer slurry, then taking out the preheated mold and pouring the prepolymer slurry into it, and then putting it into an 80°C oven to activate the prepolymer slurry in the mold for 50 minutes. Then, it is constant-temperature cured at 75°C for 36 hours, and then it is taken out and demolded to obtain the resin coating material.

[0052] Comparative Example 6

[0053] A resin coating material is prepared from the following raw materials in the following weight proportions: 65 parts of butyl methacrylate prepolymer liquid, 15 parts of KH570, 10 parts of KH550, 0.1 parts of N,N-dimethylaniline, and 0.2 parts of benzoyl peroxide. The preparation method comprises the following steps: firstly, the butyl methacrylate prepolymer liquid, silicon monomer and aluminum hydroxide are stirred and mixed at room temperature and 400r / min for 20min, then a promoter and an initiator are added and stirred and mixed at room temperature and 400r / min for 20min, after stirring, vacuum degassing for 30min to obtain a prepolymer slurry, then taking out the preheated mold and pouring the prepolymer slurry into it, and then putting it into a 45°C oven to activate the prepolymer slurry in the mold for 50min. Then, constant temperature curing is performed at 40°C for 36h, and then the mold is removed and demolded to obtain the resin coating material.

[0054] Table 1 lists the raw material ratios for preparing the coating layer materials in the examples and comparative examples.

[0055] Table 2 lists the comprehensive properties and curing temperatures of the ablation-resistant resin coating materials prepared in the examples and comparative examples, among which the coating material prepared in Example 1 has excellent properties and low curing temperature, indicating that the prepared ablation-resistant resin coating material has great application potential.

[0056] Table 1 Raw material ratios for preparing resin coating materials in Examples and Comparative Examples

[0057]

[0058]

[0059] Table 1 Performance test data of resin coating materials prepared in Examples and Comparative Examples

[0060]

[0061] By comparison, it can be seen that compared with mica powder and other ablation-resistant fillers, aluminum hydroxide can further improve the mechanical properties, ablation resistance and softening temperature of the coating material. Compared with the use of one silicon monomer, the use of two silicon monomers in combination to modify the resin matrix can further improve the mechanical properties, ablation resistance and softening temperature of the coating material, and the modification effect of using silicon monomer KH570 is better than that of using silicon monomer KH550. Compared with Example 3, it can be seen that compared with the unmodified resin matrix, the use of two silicon monomers in combination to modify the resin matrix can further improve the mechanical properties, ablation resistance and softening temperature of the coating material, and reduce the curing temperature. Compared with other unsaturated resin matrices, the use of butyl methacrylate as the resin matrix can further improve the mechanical properties, ablation resistance and softening temperature of the coating material, and reduce the curing temperature. Comparison between Example 1 and Comparative Example 5 shows that compared with other modifier monomers, the use of two silicon monomers to modify the resin matrix can further improve the mechanical properties, ablation resistance and softening temperature of the coating material, and reduce the curing temperature. Comparison between Example 1 and Comparative Example 6 shows that compared with no ablation-resistant filler, the use of aluminum hydroxide as an ablation-resistant filler can further improve the mechanical properties, ablation resistance and softening temperature of the coating material.

[0062] The above is only a specific implementation of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions are given with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A low-temperature curing, high-softening-temperature, ablation-resistant resin coating material, characterized in that: The invention is prepared from the following raw materials in the following weight proportions: 60-70 parts of butyl methacrylate prepolymer liquid, 20-30 parts of silicon monomer, 5-15 parts of ablation-resistant filler, 0-1 part of accelerator, and 0-2 parts of initiator; wherein the accelerator and the initiator are not 0, and the butyl methacrylate prepolymer liquid is prepared by dissolving polybutyl methacrylate in butyl methacrylate monomer.

2. The low-temperature curing and high-softening-temperature ablation-resistant resin coating material according to claim 1, characterized in that: The mass concentration of polybutyl methacrylate in the butyl methacrylate prepolymer solution is 5-20%.

3. The low temperature curing and high softening temperature ablation resistant resin coating material according to claim 1, characterized in that: The silicon monomer is two or more of γ-aminopropyltriethoxysilane, vinyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and methacryloxypropylmethyldimethoxysilane.

4. The low temperature curing high softening temperature ablation resistant resin coating material according to claim 1, characterized in that: The ablation-resistant filler is one or more of mica powder, zirconium oxide, aluminum hydroxide and titanium dioxide.

5. The low temperature curing and high softening temperature ablation resistant resin coating material according to claim 1, characterized in that: The accelerator is one or more of vinyltriamine, m-phenylenediamine, diaminodiphenylmethane and N,N-dimethylaniline.

6. The low temperature curing high softening temperature ablation resistant resin coating material according to claim 1, characterized in that: The initiator is one or more of benzoyl peroxide, azobisisobutyronitrile, ammonium persulfate and dimethyl azobisisobutyrate.

7. The method for preparing the low-temperature curing and high-softening-temperature ablation-resistant resin coating material according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Blending of resin matrix and filler: First, butyl methacrylate prepolymer liquid, silicon monomer and ablation-resistant filler are stirred and mixed at room temperature, then accelerator and initiator are added and stirred and mixed, and then vacuum degassing is performed to obtain prepolymer slurry; (2) Curing of the resin coating material: After step (1) is completed, take out the preheated mold and pour the prepolymer slurry into it. Then put it into an oven to activate the prepolymer slurry in the mold, and then cure it at a constant temperature. Take it out and demold it to obtain a low-temperature cured, high-softening-temperature, ablation-resistant resin coating material.

8. The method for preparing the low-temperature curing and high-softening-temperature ablation-resistant resin coating material according to claim 7, characterized in that: In step (1), the stirring speed is 300-500 r / min, and the vacuum degassing time is 20-40 min.

9. The method for preparing the low-temperature curing and high-softening-temperature ablation-resistant resin coating material according to claim 7, characterized in that: In step (2), the activation temperature of the prepolymer slurry is 40-50°C, and the activation time is 20-50 min.

10. The method for preparing the low-temperature curing and high-softening-temperature ablation-resistant resin coating material according to claim 7, characterized in that: In step (2), the curing temperature is 40-50°C and the curing time is 24-48 h.

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