High-strength high-impact low-dielectric polyimide composition and method for preparing the same

Abstract

This invention discloses a high-strength, high-impact, low-dielectric polyimide composition and its preparation method. The polyimide composition is prepared from the following components in parts by weight: 1000 parts diamine, 600-1200 parts acicular wollastonite, 3-15 parts aluminate coupling agent, and further includes tetracarboxylic acid dianhydride, wherein the molar ratio of tetracarboxylic acid dianhydride to diamine is 1:1. This invention uses high aspect ratio acicular wollastonite as a filler, resulting in significantly improved strength and impact resistance, and a significantly reduced dielectric constant. The use of the aluminate coupling agent significantly increases the interfacial bonding between the high aspect ratio acicular wollastonite and the polyimide, not only improving the mechanical properties of the polyimide composition but also further reducing its dielectric constant. The polyimide composition obtained by this invention features low dielectric constant, high strength, and excellent impact resistance.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials, and specifically relates to a high-strength, high-impact, low-dielectric polyimide composition and its preparation method. Background Technology

[0002] Polyimide (PI) refers to a class of polymers containing imide rings (-CO-N-CO-) in their main chain. It is one of the best-performing organic polymer materials. It can withstand temperatures above 400℃, with a long-term operating temperature range of -200 to 300℃. Some varieties have no distinct melting point. It exhibits high insulation properties, with a dielectric constant of 4.0 at 103 Hz and a dielectric loss of only 0.004 to 0.007, classifying it as an F to H grade insulation. Based on the chemical structure of the repeating units, polyimides can be classified into aliphatic, semi-aromatic, and aromatic polyimides. Based on interchain interactions, they can be classified into cross-linked and non-cross-linked types.

[0003] Polyimide, as a special engineering material, has been widely used in aerospace, microelectronics, liquid crystals, nanotechnology, separation membranes, lasers, and other fields. In the 1960s, countries worldwide listed the research, development, and utilization of polyimide as one of the most promising special engineering plastics of the 21st century. Due to its outstanding performance and synthesis characteristics, polyimide's enormous application potential, whether as a structural or functional material, has been fully recognized. It is hailed as a "problem solver," and it is believed that without polyimide, today's microelectronics technology would not exist.

[0004] With the rapid development of 5G technology and the massive increase in 5G base stations, the application of components such as printed circuit boards, antenna elements, and radomes has grown significantly. However, these components require properties such as low dielectric constant, resistance to high and low temperatures, high strength, and high toughness. The dielectric properties, strength, and toughness of polyimide need further improvement. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical defects and provide a high-strength, high-impact, low-dielectric polyimide composition and its preparation method.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A high-strength, high-impact, low-dielectric polyimide composition is prepared from the following components in parts by weight: 1000 parts of diamine, 600-1200 parts of acicular wollastonite, 3-15 parts of aluminate coupling agent, and further comprising tetracarboxylic acid dianhydride, wherein the molar ratio of the tetracarboxylic acid dianhydride to the diamine is 1:1.

[0008] Preferably, the diamine is selected from at least one of p-phenylenediamine and 4,4'-diphenyl sulfone diamine.

[0009] Preferably, the aspect ratio of the needle-shaped wollastonite is 22-26; the mesh size is 1000-1250 mesh.

[0010] Preferably, the tetracarboxylic acid dianhydride is selected from at least one of pyromellitic dianhydride and biphenyltetracarboxylic acid dianhydride.

[0011] The present invention also provides a method for preparing the above-described high-strength, high-impact, low-dielectric polyimide composition, comprising the following steps:

[0012] (1) Heat the needle-shaped wollastonite and aluminate coupling agent to 100-110℃ respectively, and spray 3-15 parts of aluminate coupling agent evenly on the surface of 600-1200 parts of needle-shaped wollastonite to obtain a mixture; after cooling to room temperature, add the mixture to 5000-6000 parts of solvent and stir to disperse the needle-shaped wollastonite evenly to obtain a dispersion; heating the needle-shaped wollastonite and aluminate coupling agent before spraying is beneficial to more sufficient contact between wollastonite and aluminate coupling agent, and the resulting composite product has better performance.

[0013] (2) Under an inert atmosphere, add 1000 parts of diamine to the dispersion at room temperature and stir until the diamine is fully dissolved in N,N-dimethylacetamide. Within 1-2 hours, while maintaining the stirring speed, add tetracarboxylic acid dianhydride in multiple portions, with the total amount of tetracarboxylic acid dianhydride added in a molar ratio of 1:1 to the diamine. Preferably, the tetracarboxylic acid dianhydride is added in at least two portions to ensure a gentler reaction, preventing excessive aggression and resulting in more stable product performance. More preferably, the inert atmosphere is nitrogen or carbon dioxide. The solvent is capable of fully dissolving both the diamine and the tetracarboxylic acid dianhydride, preferably N,N-dimethylacetamide.

[0014] (3) After stirring for 5-10 hours, the resulting solution is poured into a mold and dried in an oven at 100-150°C for 12-24 hours to remove the solvent; then it is placed in a muffle furnace and kept at 280-320°C for 3-5 hours to complete the curing and obtain the target product.

[0015] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0016] 1. This invention uses high aspect ratio acicular wollastonite as a filler, which significantly improves strength and impact resistance and significantly reduces dielectric constant compared to talc, calcium carbonate, and ordinary wollastonite.

[0017] 2. The present invention uses aluminate coupling agent 212, which is a special coupling agent for polyimide. Compared with coupling agent KH550, triisostearoyl titanate isopropyl, bis(dioctyloxypyrophosphate) ethylene titanate, and bis(ethyl acetoacetate) titanate diisopropyl, it can significantly increase the interfacial bonding ability between high aspect ratio needle-shaped wollastonite and polyimide. It can not only improve the mechanical properties of the polyimide composition, but also further reduce the dielectric constant of the composition.

[0018] 3. The polyimide composition obtained by this invention has the characteristics of low dielectric constant, high strength, and excellent impact resistance. It can be used in low-dielectric applications such as radomes, antenna elements, and very large-scale integrated circuit devices. Detailed Implementation

[0019] The present invention will be further described below with reference to embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] The material grades and suppliers in each embodiment and comparative example are shown below:

[0021] Needle-shaped wollastonite with an aspect ratio of 25 and a mesh size of 1250, produced by Weifang Kangzhuang Building Materials Co., Ltd.

[0022] Wollastonite with an aspect ratio of 15 and a mesh size of 800, produced by Weifang Kangzhuang Building Materials Co., Ltd.

[0023] Talc and calcium carbonate with a particle size of 2000 mesh, Changxing Huayang Plastic Materials Co., Ltd.

[0024] Both pyromellitic dianhydride and biphenyltetracarboxylic anhydride are industrial grade, manufactured by Shandong Xuchen Chemical Technology Co., Ltd.

[0025] p-Phenylenediamine and 4,4'-diphenyl sulfone diamine are both industrial grade, manufactured by Shandong Huian Chemical.

[0026] N,N-Dimethylacetamide, industrial grade, Shanghai Hongzhuang Chemical Technology.

[0027] Aluminate coupling agent, grade 212, Wuhan Huaxiang Kejie Biotechnology Co., Ltd.

[0028] The coupling agent KH550, triisostearoyl titanate isopropyl ester, bis(dioctyloxypyrophosphate) ethylene titanate, and bis(ethyl acetoacetate) diisopropyl titanate were all purchased from Nanjing Phyteng New Material Technology Co., Ltd.

[0029] The reagents described above are only for illustrating the source and composition of the reagents used in the experiments of this invention, so as to provide full disclosure, and do not imply that the invention cannot be achieved by using other similar reagents or reagents provided by other suppliers.

[0030] Example 1

[0031] A method for preparing a high-strength, high-impact, low-dielectric polyimide composition includes the following steps:

[0032] (1) Heat the needle-shaped wollastonite and aluminate coupling agent to 100°C respectively, and spray 3 parts of aluminate coupling agent evenly on the surface of 600 parts of needle-shaped wollastonite to obtain a mixture; after cooling to room temperature, add the mixture to 5000 parts of N,N-dimethylacetamide and stir to disperse the needle-shaped wollastonite evenly to obtain a dispersion.

[0033] (2) Under nitrogen protection, add 1000 parts of p-phenylenediamine to the dispersion at room temperature and stir to fully dissolve the p-phenylenediamine in N,N-dimethylacetamide. Within 1 hour, while maintaining the stirring speed, add pyromellitic dianhydride in two equal portions; the total amount of pyromellitic dianhydride added is in a molar ratio of 1:1 to p-phenylenediamine.

[0034] (3) After stirring for 5 hours, the resulting solution was poured into a mold and dried in an oven at 100°C for 24 hours. Then it was placed in a muffle furnace and kept at 320°C for 3 hours to obtain the target product.

[0035] Example 2

[0036] A method for preparing a high-strength, high-impact, low-dielectric polyimide composition includes the following steps:

[0037] (1) Heat the needle-shaped wollastonite and aluminate coupling agent to 100°C respectively, and spray 15 parts of aluminate coupling agent evenly on the surface of 1200 parts of needle-shaped wollastonite to obtain a mixture; after cooling to room temperature, add the mixture to 6000 parts of N,N-dimethylacetamide, stir to disperse the needle-shaped wollastonite evenly, and obtain a dispersion.

[0038] (2) Under carbon dioxide gas protection, add 1000 parts of 4,4'-diphenyl sulfone diamine to the dispersion at room temperature, and stir to fully dissolve the 4,4'-diphenyl sulfone diamine in N,N-dimethylacetamide. Over 1.5 hours, while maintaining the stirring speed, add pyromellitic dianhydride in three equal portions; the molar ratio of the total amount of pyromellitic dianhydride added to 4,4'-diphenyl sulfone diamine is 1:1.

[0039] (3) After stirring for 10 hours, the resulting solution was poured into a mold and dried in an oven at 150°C for 12 hours. Then it was placed in a muffle furnace and kept at 280°C for 5 hours to obtain the target product.

[0040] Example 3

[0041] A method for preparing a high-strength, high-impact, low-dielectric polyimide composition includes the following steps:

[0042] (1) Heat the needle-shaped wollastonite and aluminate coupling agent to 100°C respectively, and spray 10 parts of aluminate coupling agent evenly on the surface of 800 parts of needle-shaped wollastonite to obtain a mixture; after cooling to room temperature, add the mixture to 5500 parts of N,N-dimethylacetamide, stir to disperse the needle-shaped wollastonite evenly, and obtain a dispersion.

[0043] (2) Under nitrogen protection, add 1000 parts of p-phenylenediamine to the dispersion at room temperature and stir to fully dissolve the p-phenylenediamine in N,N-dimethylacetamide. Within 2 hours, while maintaining the stirring speed, add pyromellitic dianhydride in 4 equal portions; the total amount of pyromellitic dianhydride added is in a molar ratio of 1:1 to p-phenylenediamine.

[0044] (3) After stirring for 8 hours, the resulting solution was poured into a mold and dried in an oven at 120°C for 16 hours. Then it was placed in a muffle furnace and kept at 300°C for 3 hours to obtain the target product.

[0045] Example 4

[0046] A method for preparing a high-strength, high-impact, low-dielectric polyimide composition includes the following steps:

[0047] (1) Heat the needle-shaped wollastonite and aluminate coupling agent to 100°C respectively, and spray 8 parts of aluminate coupling agent evenly on the surface of 1000 parts of needle-shaped wollastonite to obtain a mixture; after cooling to room temperature, add the mixture to 5500 parts of N,N-dimethylacetamide, stir to disperse the needle-shaped wollastonite evenly, and obtain a dispersion.

[0048] (2) Under carbon dioxide gas protection, add 1000 parts of 4,4'-diphenyl sulfone diamine to the dispersion at room temperature, and stir to fully dissolve the 4,4'-diphenyl sulfone diamine in N,N-dimethylacetamide. Within 2 hours, while maintaining the stirring speed, add pyromellitic dianhydride in 3 equal portions; the molar ratio of the total amount of pyromellitic dianhydride added to 4,4'-diphenyl sulfone diamine is 1:1.

[0049] (3) After stirring for 6 hours, the resulting solution was poured into a mold and dried in an oven at 120°C for 24 hours. Then it was placed in a muffle furnace and kept at 300°C for 4 hours to obtain the target product.

[0050] Comparative Example 1

[0051] Compare with Example 4. In this example, talc powder is used instead of acicular wollastonite, while all other technical parameters remain the same.

[0052] Comparative Example 2

[0053] Compare with Example 4. In this example, calcium carbonate was used instead of acicular wollastonite, while all other technical parameters remained the same.

[0054] Comparative Example 3

[0055] Compare with Example 4. In this example, wollastonite was used instead of acicular wollastonite, while all other technical parameters remained the same.

[0056] Comparative Example 4

[0057] Compare with Example 4. In this example, the commonly used coupling agent KH550 is used instead of the aluminate coupling agent, while all other technical parameters remain the same.

[0058] Comparative Example 5

[0059] Compare with Example 4. In Example 4, the commonly used coupling agent triisostearoyl titanate isopropyl ester was used instead of the aluminate coupling agent, while all other technical parameters remained the same.

[0060] Comparative Example 6

[0061] Compare with Example 4. In this example, the commonly used coupling agent bis(dioctyloxypyrophosphate) ethylene titanate was used instead of the aluminate coupling agent, while all other technical parameters remained the same.

[0062] Comparative Example 7

[0063] Compare with Example 4. In this example, the aluminate coupling agent was replaced with diisopropyl bis(ethyl acetoacetate) titanate, while all other technical parameters remained the same.

[0064] Performance testing methods:

[0065] The products prepared in each embodiment and comparative example were subjected to performance testing under the following conditions:

[0066] Tensile strength was tested according to standard ASTM D638. The test specimen was dumbbell-shaped with dimensions (length × width × thickness) of 170 mm × 13 mm × 3.2 mm. The tensile speed was 5 mm / min.

[0067] The notched impact strength of simply supported beams was tested according to the standard ASTM D6110-2018. The test specimen dimensions (length × width × thickness) were 127mm × 13mm × 3.2mm, with a V-notch and a notch depth of 1 / 5.

[0068] The dielectric constant test strip has a size of 8mm×3.2mm×1.6mm. After uniformly coating the surface of the test strip with silver electrodes, the dielectric constant is tested in accordance with GB / T 1409-2006, and the test frequency is 1MHz.

[0069] The performance test results of the products obtained in each embodiment and comparative example are shown in Table 1.

[0070] Table 1. Performance test results of the products obtained in each embodiment and comparative example.

[0071]

[0072] The data above shows that this invention uses high aspect ratio acicular wollastonite as a filler, which significantly improves strength and impact performance and significantly reduces dielectric constant compared to talc, calcium carbonate, and ordinary wollastonite. This invention uses aluminate coupling agent 212, a coupling agent specifically for polyimide, in a ratio with coupling agent KH550, isopropyl triisostearoyl titanate, bis(dioctyloxypyrophosphate) ethylene titanate, and bis(ethyl acetoacetate) diisopropyl titanate. This significantly increases the interfacial bonding ability between high aspect ratio acicular wollastonite and polypropylene, not only improving the mechanical properties of the polypropylene composition but also further reducing the dielectric constant of the composition.

[0073] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a high-strength, high-impact, low-dielectric polyimide composition, characterized in that: It is prepared from the following components in parts by weight: 1000 parts of diamine, 600-1200 parts of acicular wollastonite, 3-15 parts of aluminate coupling agent, and also includes tetracarboxylic acid dianhydride, wherein the molar ratio of tetracarboxylic acid dianhydride to diamine is 1:1; the aspect ratio of acicular wollastonite is 22-26, and the aluminate coupling agent is aluminate coupling agent 212; The preparation method of the high-strength, high-impact, low-dielectric polyimide composition includes the following steps: (1) Heat the needle-shaped wollastonite and aluminate coupling agent to 100°C respectively, and spray 3-15 parts of aluminate coupling agent evenly on the surface of 600-1200 parts of needle-shaped wollastonite to obtain a mixture; after cooling to room temperature, add the mixture to 5000-6000 parts of solvent and stir to disperse the needle-shaped wollastonite evenly to obtain a dispersion. (2) Under an inert atmosphere, add 1000 parts of diamine to the dispersion at room temperature and stir to fully dissolve the diamine in N,N-dimethylacetamide; within 1-2 hours, while maintaining the stirring speed, add tetracarboxylic acid dianhydride in multiple portions, with the total amount of tetracarboxylic acid dianhydride added being in a molar ratio of 1:1 to the diamine. (3) After stirring for 5-10 hours, the resulting solution is poured into a mold and dried in an oven at 100-150℃ for 12-24 hours; then it is placed in a muffle furnace and kept at 280-320℃ for 3-5 hours to obtain the target product.

2. The method for preparing the high-strength, high-impact, low-dielectric polyimide composition according to claim 1, characterized in that: The diamine is selected from at least one of p-phenylenediamine and 4,4'-diphenyl sulfone diamine.

3. The method for preparing the high-strength, high-impact, low-dielectric polyimide composition according to claim 1, characterized in that: The tetracarboxylic acid dianhydride is selected from at least one of pyromellitic dianhydride and biphenyltetracarboxylic dianhydride.

4. The method for preparing the high-strength, high-impact, low-dielectric polyimide composition according to claim 1, characterized in that: The inert atmosphere is nitrogen or carbon dioxide.

5. The method for preparing the high-strength, high-impact, low-dielectric polyimide composition according to claim 1, characterized in that: The solvent is N,N-dimethylacetamide.

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