An intermediate paint for enhancing electromagnetic shielding properties and a method for preparing the same

Abstract

The application provides an intermediate paint coating with enhanced electromagnetic shielding property and a preparation method thereof, and belongs to the technical field of paint.The coating contains the following components: epoxy resin, MOF Ni3(HITP)2, TiNbAlC MAX phase ceramic material, soybean oil amide propyl betaine, potassium magnesium fluosilicate, conductive mica powder, whisker carbon nanotube, silver-coated copper conductive powder, leveling agent, defoaming agent, ultraviolet absorber, hindered phenolic antioxidant, phosphite antioxidant, aziridine crosslinking agent and the like.The components are used in combination, and the coating is prepared through a special preparation method.The coating has excellent electromagnetic shielding property, especially in the high-frequency band, and is resistant to aging, has good durability and stable electromagnetic shielding capacity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coatings, and particularly relates to an intermediate paint coating for enhancing electromagnetic shielding and a preparation method thereof. BACKGROUND

[0002] With the widespread application of electronic devices and the rapid development of wireless communication technology, electromagnetic interference has a greater and greater impact on the normal operation of electronic devices and the health and safety of humans. The sources of electromagnetic radiation are very extensive, including but not limited to communication base stations, broadcast television towers, radar stations, high-voltage lines, electronic devices, etc. These devices will produce electromagnetic radiation of different frequencies and intensities during operation, causing interference to the surrounding environment and equipment. For example, in places with a high concentration of electronic devices, electromagnetic interference may cause device performance degradation, data transmission errors, and even device damage. In the medical field, electromagnetic radiation may affect the accuracy and safety of medical devices, posing risks to patient diagnosis and treatment.

[0003] Traditional electromagnetic shielding methods mainly include the use of metal shielding covers, metal wire meshes, etc. However, these methods have some limitations. For example, metal shielding covers are bulky and heavy, making them inconvenient to install and use; the shielding effect of metal wire meshes is limited and they are easily damaged. In addition, these traditional methods are difficult to achieve effective electromagnetic shielding in some special situations, such as curved structures, narrow spaces, etc.

[0004] To solve these problems, researchers have begun to focus on developing new electromagnetic shielding materials, among which electromagnetic shielding coatings have become a research hotspot. Such coatings have the following advantages: first, the coating has good adaptability. It can be applied to surfaces of various shapes and materials, including flat surfaces, curved surfaces, irregular shapes, etc., and can meet the electromagnetic shielding needs of different occasions. Whether it is metal, plastic, glass, or composite materials, electromagnetic shielding can be achieved by coating electromagnetic shielding coatings. Second, the coating has a relatively light weight. Compared with traditional metal shielding materials, electromagnetic shielding coatings greatly reduce weight, which is of great significance for some applications with strict weight requirements, such as aerospace, portable electronic devices, etc. Third, the coating has good construction performance. It can be applied by spraying, brushing, dipping, etc., and is easy to operate, allowing for quick electromagnetic shielding of large areas.

[0005] In addition, electromagnetic shielding coatings can be formulated according to different requirements to meet different frequency ranges and shielding strength requirements. By selecting appropriate conductive fillers, resin matrices, and additives, the electromagnetic shielding performance of the coating can be adjusted to be suitable for various complex electromagnetic environments.

[0006] Currently, there have been many studies on electromagnetic shielding coatings at home and abroad. Common conductive fillers include metal powders (such as silver powder, copper powder, nickel powder, etc.), carbon materials (such as carbon black, graphite, carbon fiber, etc.), conductive polymers, etc. These conductive fillers form a conductive network in the coating, achieving reflection, absorption and scattering of electromagnetic waves, thereby achieving electromagnetic shielding.

[0007] However, although the electromagnetic shielding coating has many advantages, there are still some problems to be solved, including: how to improve the electromagnetic shielding performance of the coating, especially in the high frequency band; how to improve the stability and durability of the coating, so that it maintains good electromagnetic shielding performance in the long-term use process. SUMMARY

[0008] In view of the deficiencies of existing electromagnetic shielding coatings in terms of shielding performance, stability and durability in the high frequency band, the present application provides an electromagnetic shielding intermediate paint and a preparation method thereof. The coating contains epoxy resin, MOF Ni3(HITP)2, TiNbAlC MAX phase ceramic material, soybean oil amide propyl betaine, potassium magnesium fluosilicate, conductive mica powder, whisker carbon nanotube, silver-coated copper conductive powder, aziridine crosslinking agent and other components. The use of each component has excellent electromagnetic shielding performance, especially in the high frequency band, and good anti-tiger and durability, and stable electromagnetic shielding capacity. The specific technical scheme is as follows:

[0009] An electromagnetic shielding intermediate paint, the coating includes the following mass fractions of raw materials: 40-50 parts of epoxy resin, 0.3-0.8 parts of MOF Ni3(HITP)2, 1-3 parts of TiNbAlC MAX phase ceramic material, 0.3-0.5 parts of soybean oil amide propyl betaine, 2-5 parts of potassium magnesium fluosilicate, 8-12 parts of conductive mica powder, 5-10 parts of whisker carbon nanotube, 3-5 parts of silver-coated copper conductive powder, 1-2 parts of leveling agent, 1-2 parts of defoaming agent, 1-2 parts of ultraviolet absorber, 1-1.5 parts of hindered phenolic antioxidant, 0.5-1 parts of phosphite antioxidant, 2-5 parts of aziridine crosslinking agent, 0.5-1.5 parts of hydroxyethyl cellulose, 20-30 parts of solvent.

[0010] In the above-mentioned coating, the MOF Ni3(HITP)2 has a specification of: length range of 400 nm-1 μm, diameter range of 19-26 nm.

[0011] In the above-mentioned coating, the TiNbAlC MAX phase ceramic material has a flake diameter range of 2 μm-30 μm.

[0012] In the above-mentioned coating, the potassium magnesium fluosilicate has a particle size range of less than 800 mesh.

[0013] In the above coating, the particle size of the conductive mica powder ranges below 800 mesh.

[0014] In the above coating, the length of the whisker carbon nanotube ranges from 2 μm to 15 μm, and the outer diameter ranges from 20 nm to 200 nm.

[0015] In the above coating, the particle size of the silver-coated copper conductive powder ranges below 18 μm.

[0016] In the above coating, the leveling agent is BYK-333 leveling agent, BYK-358N leveling agent, TEGO Glide 410 leveling agent, or TEGO Flow 370 leveling agent.

[0017] In the above coating, the defoaming agent is BYK-066N defoaming agent, BYK-024 defoaming agent, TEGO Foamex 810 defoaming agent, or TEGO Airex 902W defoaming agent.

[0018] In the above coating, the ultraviolet absorber is Tinuvin P ultraviolet absorber, Tinuvin 1577 ultraviolet absorber, Ciba UV-326 ultraviolet absorber, or Ciba UV-1164 ultraviolet absorber.

[0019] In the above coating, the hindered phenol antioxidant is Irganox 1010 antioxidant or Ciba Irgafos 168 antioxidant.

[0020] In the above coating, the phosphite antioxidant is Irgafos 126 antioxidant or Ciba Ultranox 626 antioxidant.

[0021] In the above coating, the solvent is butanol.

[0022] The preparation method of the above intermediate paint coating for enhancing electromagnetic shielding property comprises the following steps:

[0023] S1: according to mass fraction, soybean oil amide propyl betaine and defoaming agent are added into 50 wt% solvent, mixed uniformly, then MOF Ni3(HITP)2 is added and mixed uniformly, to obtain material A;

[0024] S2: according to mass fraction, TiNbAlC MAX phase ceramic material and whisker carbon nanotube are air-flow mixed uniformly, then silver-coated copper conductive powder is added and air-flow mixed uniformly, then potassium magnesium fluorosilicate and conductive mica powder are added and air-flow mixed uniformly, to obtain material B;

[0025] S3: according to the mass fraction, hydroxyethyl cellulose is added into the remaining 50wt% solvent, and is uniformly premixed and dissolved to obtain material C;

[0026] S4: according to the mass fraction, the leveling agent is added into material A and uniformly mixed, then material B is added and uniformly mixed, then aziridine crosslinking agent is added and uniformly mixed, then epoxy resin, ultraviolet absorber, hindered phenolic antioxidant and phosphite antioxidant are added and uniformly mixed, finally material C is added and uniformly mixed to obtain the coating.

[0027] The above-mentioned intermediate paint coating for enhancing electromagnetic shielding property is used as an intermediate paint for enhancing electromagnetic shielding property.

[0028] The intermediate paint coating for enhancing electromagnetic shielding property and the preparation method thereof have the following beneficial effects:

[0029] Firstly, the coating contains epoxy resin, MOF Ni3(HITP)2, TiNbAlC MAX phase ceramic material, soybean oil amide propyl betaine, potassium magnesium fluorosilicate, conductive mica powder, whisker carbon nanotube, silver-coated copper conductive powder, leveling agent, defoaming agent, ultraviolet absorber, hindered phenolic antioxidant, phosphite antioxidant, aziridine crosslinking agent and other components.

[0030] Epoxy resin is the main film-forming material, which forms a continuous coating film through curing reaction, and other components are wrapped in it, providing basic adhesion and physical barrier function for the coating. MOF Ni3(HITP)2has a porous structure and a large specific surface area, which can absorb electromagnetic waves and play a role in electromagnetic shielding; its porous structure can make electromagnetic waves reflect and scatter multiple times inside, thereby reducing the transmittance of electromagnetic waves. TiNbAlC MAX phase ceramic material has good electrical conductivity and high temperature resistance, etc. In terms of electromagnetic shielding, it can reflect and absorb electromagnetic waves, and its electrical conductivity enables it to form a conductive path under the action of an electric field, reflecting electromagnetic waves back, and also absorbing part of the electromagnetic waves through internal electron transition and other ways. Soybean oil amide propyl betaine as a surfactant can reduce the surface tension of the coating, improve the wettability and permeability of the coating to the substrate, and make the coating spread better on the substrate surface, which helps to improve the coating quality and adhesion. The structure of conductive mica powder can form a conductive network by overlapping each other in the coating film, reflecting and scattering electromagnetic waves, thereby enhancing the electromagnetic shielding effectiveness. Carbon nanotube whiskers have excellent electrical conductivity and high aspect ratio, which can form a conductive path by connecting each other in the coating, effectively reflecting and conducting electromagnetic waves, greatly improving the electromagnetic shielding performance, and at the same time, the high aspect ratio can also enhance the mechanical properties of the coating. Silver-coated copper conductive powder combines the high electrical conductivity of silver and the cost advantage of copper, which can form a conductive channel in the coating to shield electromagnetic waves through reflection and conduction. Nitrogen propylene crosslinking agent promotes the crosslinking reaction of resin components in the coating, forming a more compact three-dimensional network structure, and improving the adhesion and other properties of the coating film.

[0031] II. MOF Ni3(HITP)2mainly reduces the transmittance of electromagnetic waves by adsorption and multiple reflections inside, and TiNbAlC MAX phase ceramic material can both reflect and absorb electromagnetic waves. When used together, they can play a role under different electromagnetic wave action mechanisms and form a complement. For example, when electromagnetic waves reach the coating film, part of them is first reflected by TiNbAlC MAX phase ceramic material, and the electromagnetic waves entering the inside of the coating film are then adsorbed and scattered by MOF Ni3(HITP)2, thereby greatly enhancing the overall electromagnetic shielding effect and also improving the electrical conductivity and stability of the aging-resistant electromagnetic shielding. The porous structure of MOF Ni3(HITP)2can provide certain adhesion sites for TiNbAlC MAX phase ceramic material, making the distribution of the two in the coating film more reasonable and improving the overall stability of the coating film.

[0032] In the preparation method S1, the soybean oil amide propyl betaine and the defoaming agent are first mixed in the solvent to fully disperse the surfactant and the defoaming agent in the solvent. Then, the MOF Ni3(HITP)2 is added and the stirring speed is increased, which is conducive to the uniform dispersion of the MOF Ni3(HITP)2 in the mixed system and avoids agglomeration, laying a foundation for the subsequent formation of a uniform coating.

[0033] In the preparation method S2, the TiNbAlC MAX phase ceramic material and the carbon nanotube whisker are mixed by airflow, which can fully contact and mix the two materials in the gas phase environment and avoid affecting the performance of the coating due to agglomeration. Then, the silver-coated copper conductive powder, potassium magnesium fluosilicate and conductive mica powder are sequentially added and mixed to gradually build the conductive and physical performance enhancement system in the coating and form a uniform mixture of multiple functional components.

[0034] In the preparation method S3, the hydroxyethyl cellulose is pre-mixed and dissolved uniformly in the remaining solvent to separately process the thickening agent, ensure its complete dissolution in the solvent, form a uniform solution, and better control the viscosity of the coating.

[0035] In the preparation method S4, the leveling agent is added to the material A and mixed to give the coating good leveling performance. Then, the material B is added to fully combine the mixture containing electromagnetic shielding and physical performance enhancement components with the material A and mix uniformly. Then, the aziridine crosslinking agent is added to start promoting the crosslinking reaction of the coating and improve the performance of the coating film. The epoxy resin, the ultraviolet absorber, the hindered phenolic antioxidant and the phosphite antioxidant are added, and finally the material C is added to adjust the viscosity of the coating. After this series of mixing processes, the coating with stable and uniform performance is finally obtained, which effectively ensures the uniformity of the coating components and further improves the electromagnetic shielding, conductive smoothness and other effects of the coating. DETAILED DESCRIPTION

[0036] The application will be further described below in combination with specific implementation examples, but the application is not limited to these examples.

[0037] Example 1

[0038] An intermediate paint coating for enhancing electromagnetic shielding performance, the coating comprises the following raw materials in mass fraction: 45 parts of epoxy resin, 0.5 parts of MOF Ni3(HITP)2, 2 parts of TiNbAlC MAX phase ceramic material, 0.4 parts of soybean oil amide propyl betaine, 3.5 parts of potassium magnesium fluosilicate, 10 parts of conductive mica powder, 8 parts of carbon nanotube whisker, 4 parts of silver-coated copper conductive powder, 1.5 parts of leveling agent, 1.5 parts of defoaming agent, 1.5 parts of ultraviolet absorber, 1.2 parts of hindered phenolic antioxidant, 0.8 parts of phosphite antioxidant, 3.5 parts of aziridine crosslinking agent, 1 part of hydroxyethyl cellulose and 25 parts of butanol.

[0039] The flow agent is BYK-333 flow agent. The defoaming agent is BYK-066N defoaming agent. The ultraviolet absorber is Tinuvin P ultraviolet absorber. The hindered phenol antioxidant is Irganox 1010 antioxidant. The phosphite antioxidant is Irgafos 126 antioxidant.

[0040] The preparation method of the above-mentioned intermediate paint for enhancing electromagnetic shielding property comprises the following steps:

[0041] S1: according to the mass fraction, soybean oil amide propyl betaine and defoaming agent are added into 50wt% solvent, mixed at 400r / min for 12min, then MOF Ni3(HITP)2 is added, mixed at 1000r / min for 18min, to obtain material A;

[0042] S2: according to the mass fraction, TiNbAlC MAX phase ceramic material and carbon nanotube whisker are airflow mixed for 40min, then silver-coated copper conductive powder is added and airflow mixed for 40min, then potassium magnesium fluorosilicate and conductive mica powder are added and airflow mixed for 40min, to obtain material B;

[0043] S3: according to the mass fraction, hydroxyethyl cellulose is added into the remaining 50wt% solvent, pre-mixed and dissolved uniformly to obtain material C;

[0044] S4: according to the mass fraction, the flow agent is added into material A, uniformly mixed at 600r / min for 12min, then material B is added, uniformly mixed at 900r / min for 18min, then aziridine crosslinking agent is added, uniformly mixed at 900r / min for 25min, then epoxy resin, ultraviolet absorber, hindered phenol antioxidant and phosphite antioxidant are added, uniformly mixed at 1100r / min for 25min, finally material C is added, uniformly mixed at 600r / min for 12min, to obtain the paint.

[0045] The paint prepared in this example is used as an intermediate paint for enhancing electromagnetic shielding property.

[0046] Example 2

[0047] An intermediate paint coating for enhancing electromagnetic shielding property, the coating comprises raw materials in mass fraction: 40 parts of epoxy resin, 0.3 parts of MOF Ni3(HITP)2, 1 part of TiNbAlC MAX phase ceramic material, 0.3 parts of soybean oil amidopropyl betaine, 2 parts of potassium magnesium fluorosilicate, 8 parts of conductive mica powder, 5 parts of whisker carbon nanotube, 3 parts of silver-coated copper conductive powder, 1 part of leveling agent, 1 part of defoaming agent, 1 part of ultraviolet absorber, 1 part of hindered phenolic antioxidant, 0.5 parts of phosphite antioxidant, 2 parts of aziridine crosslinking agent, 0.5 parts of hydroxyethyl cellulose, 20 parts of butanol.

[0048] The leveling agent is BYK-358N leveling agent, the defoaming agent is BYK-024 defoaming agent, the ultraviolet absorber is Tinuvin 1577 ultraviolet absorber, the hindered phenolic antioxidant is Ciba Irgafos 168 antioxidant, and the phosphite antioxidant is Ciba Ultranox 626 antioxidant.

[0049] The preparation method of the above-mentioned intermediate paint coating for enhancing electromagnetic shielding property comprises the following steps:

[0050] S1: according to mass fraction, soybean oil amidopropyl betaine and defoaming agent are added into 50wt% solvent, mixed at 300r / min for 10min, then MOF Ni3(HITP)2 is added, mixed at 800r / min for 15min, to obtain material A;

[0051] S2: according to mass fraction, TiNbAlC MAX phase ceramic material and whisker carbon nanotube are airflow mixed for 30min, then silver-coated copper conductive powder is added and airflow mixed for 30min, then potassium magnesium fluorosilicate and conductive mica powder are added and airflow mixed for 30min, to obtain material B;

[0052] S3: according to mass fraction, hydroxyethyl cellulose is added into the remaining 50wt% solvent, pre-mixed and dissolved uniformly, to obtain material C;

[0053] S4: according to mass fraction, leveling agent is added into material A, uniformly mixed at 500r / min for 10min, then material B is added, uniformly mixed at 800r / min for 15min, then aziridine crosslinking agent is added, uniformly mixed at 800r / min for 20min, then epoxy resin, ultraviolet absorber, hindered phenolic antioxidant and phosphite antioxidant are added, uniformly mixed at 1000r / min for 20min, finally material C is added, uniformly mixed at 500r / min for 10min, to obtain the coating.

[0054] The coating prepared in this embodiment is used as an intermediate paint for enhancing electromagnetic shielding property.

[0055] Example 3

[0056] An intermediate paint coating for enhancing electromagnetic shielding property, the coating comprises raw materials in mass fraction: 40 parts of epoxy resin, 0.8 parts of MOF Ni3(HITP)2, 1 part of TiNbAlC MAX phase ceramic material, 0.5 parts of soybean oil amidopropyl betaine, 2 parts of potassium magnesium fluosilicate, 12 parts of conductive mica powder, 5 parts of carbon nanotube whisker, 5 parts of silver-coated copper conductive powder, 1 part of leveling agent, 2 parts of defoaming agent, 1 part of ultraviolet absorber, 1.5 parts of hindered phenolic antioxidant, 0.5 parts of phosphite antioxidant, 5 parts of aziridine crosslinking agent, 0.5 parts of hydroxyethyl cellulose, 26 parts of butanol.

[0057] The leveling agent is TEGO Glide 410 leveling agent. The defoaming agent is TEGO Foamex 810 defoaming agent. The ultraviolet absorber is Ciba UV-326 ultraviolet absorber. The hindered phenolic antioxidant is Irganox 1010 antioxidant. The phosphite antioxidant is Ciba Ultranox 626 antioxidant.

[0058] The preparation method of the above-mentioned intermediate paint coating for enhancing electromagnetic shielding property, comprising the following steps:

[0059] S1: according to mass fraction, soybean oil amidopropyl betaine and defoaming agent are added into 50wt% solvent, mixed at 300r / min for 15min, then MOF Ni3(HITP)2 is added, mixed at 800r / min for 20min, to obtain material A;

[0060] S2: according to mass fraction, TiNbAlC MAX phase ceramic material and carbon nanotube whisker are airflow mixed for 30min, then silver-coated copper conductive powder is added and airflow mixed for 50min, then potassium magnesium fluosilicate and conductive mica powder are added and airflow mixed for 30min, to obtain material B;

[0061] S3: according to mass fraction, hydroxyethyl cellulose is added into the remaining 50wt% solvent, pre-mixed and dissolved uniformly, to obtain material C;

[0062] S4: according to mass fraction, leveling agent is added into material A, uniformly mixed at 800r / min for 10min, then material B is added, uniformly mixed at 1000r / min for 15min, then aziridine crosslinking agent is added, uniformly mixed at 1000r / min for 20min, then epoxy resin, ultraviolet absorber, hindered phenolic antioxidant and phosphite antioxidant are added, uniformly mixed at 1200r / min for 20min, finally material C is added, uniformly mixed at 800r / min for 10min, to obtain the coating.

[0063] The paint prepared in the embodiment is used as an intermediate paint for enhancing electromagnetic shielding property.

[0064] Embodiment 4

[0065] An intermediate paint for enhancing electromagnetic shielding property, the paint comprising raw materials in mass fractions of 50 parts of epoxy resin, 0.8 parts of MOF Ni3(HITP)2, 3 parts of TiNbAlC MAX phase ceramic material, 0.5 parts of soybean oil amide propyl betaine, 5 parts of potassium magnesium fluosilicate, 12 parts of conductive mica powder, 10 parts of whisker carbon nanotube, 5 parts of silver-coated copper conductive powder, 2 parts of leveling agent, 2 parts of defoaming agent, 2 parts of ultraviolet absorber, 1.5 parts of hindered phenolic antioxidant, 1 part of phosphite antioxidant, 5 parts of aziridine crosslinking agent, 1.5 parts of hydroxyethyl cellulose, and 30 parts of butanol.

[0066] The leveling agent is TEGO Flow 370 leveling agent. The defoaming agent is TEGO Airex 902W defoaming agent. The ultraviolet absorber is Ciba UV-1164 ultraviolet absorber. The hindered phenolic antioxidant is Ciba Irgafos 168 antioxidant. The phosphite antioxidant is Irgafos 126 antioxidant.

[0067] The preparation method of the above-mentioned intermediate paint for enhancing electromagnetic shielding property, comprising the following steps:

[0068] S1: according to mass fractions, soybean oil amide propyl betaine and defoaming agent are added into 50wt% solvent, mixed at 500r / min for 15min, then MOF Ni3(HITP)2 is added, mixed at 1200r / min for 20min, to obtain material A;

[0069] S2: according to mass fractions, TiNbAlC MAX phase ceramic material and whisker carbon nanotube are airflow mixed for 50min, then silver-coated copper conductive powder is added and airflow mixed for 50min, then potassium magnesium fluosilicate and conductive mica powder are added and airflow mixed for 50min, to obtain material B;

[0070] S3: according to mass fractions, hydroxyethyl cellulose is added into the remaining 50wt% solvent, pre-mixed and dissolved uniformly to obtain material C;

[0071] S4: According to the mass fraction, the leveling agent is added to the material A, and uniformly mixed at 800 r / min for 15 min, then the material B is added, and uniformly mixed at 1000 r / min for 20 min, then the aziridine crosslinking agent is added, and uniformly mixed at 1000 r / min for 30 min, then the epoxy resin, the ultraviolet absorber, the hindered phenolic antioxidant and the phosphite antioxidant are added, and uniformly mixed at 1200 r / min for 30 min, and finally the material C is added, and uniformly mixed at 800 r / min for 15 min, to obtain the coating. The coating prepared in this example is used as an intermediate paint for enhancing electromagnetic shielding.

[0072] Example 5

[0073] An intermediate paint coating for enhancing electromagnetic shielding, the coating comprising the following raw materials by mass fraction: 50 parts of epoxy resin, 0.3 parts of MOF Ni3(HITP)2, 3 parts of TiNbAlC MAX phase ceramic material, 0.3 parts of soybean oil amidopropyl betaine, 5 parts of potassium magnesium fluosilicate, 8 parts of conductive mica powder, 10 parts of carbon nanotube whisker, 3 parts of silver-coated copper conductive powder, 2 parts of leveling agent, 1 part of defoaming agent, 2 parts of ultraviolet absorber, 1 part of hindered phenolic antioxidant, 1 part of phosphite antioxidant, 2 parts of aziridine crosslinking agent, 1.5 parts of hydroxyethyl cellulose, and 26 parts of butanol.

[0074] The leveling agent is BYK-333 leveling agent. The defoaming agent is BYK-024 defoaming agent. The ultraviolet absorber is Tinuvin 1577 ultraviolet absorber. The hindered phenolic antioxidant is Irganox 1010 antioxidant. The phosphite antioxidant is Irgafos 126 antioxidant.

[0075] The above-mentioned method for preparing an intermediate paint coating for enhancing electromagnetic shielding comprises the following steps:

[0076] S1: According to the mass fraction, the soybean oil amidopropyl betaine and the defoaming agent are added to 50wt% solvent, and mixed at 500 r / min for 10 min, then the MOF Ni3(HITP)2 is added, and mixed at 1200 r / min for 15 min, to obtain material A;

[0077] S2: According to the mass fraction, the TiNbAlC MAX phase ceramic material and the carbon nanotube whisker are airflow mixed for 50 min, then the silver-coated copper conductive powder is added and airflow mixed for 30 min, then the potassium magnesium fluosilicate and the conductive mica powder are added and airflow mixed for 50 min, to obtain material B;

[0078] S3: According to the mass fraction, the hydroxyethyl cellulose is added to the remaining 50wt% solvent, and pre-mixed and dissolved uniformly to obtain material C;

[0079] S4: According to the mass fraction, leveling agent is added to material A, and uniform mixing is carried out at 500 r / min for 15 min, then material B is added, and uniform mixing is carried out at 800 r / min for 20 min, then aziridine crosslinking agent is added, and uniform mixing is carried out at 800 r / min for 30 min, then epoxy resin, ultraviolet absorber, hindered phenolic antioxidant and phosphite antioxidant are added, and uniform mixing is carried out at 1000 r / min for 30 min, finally material C is added, and uniform mixing is carried out at 500 r / min for 15 min, to obtain the coating. The coating prepared in this example is used as an intermediate paint for enhancing electromagnetic shielding.

[0080] Example 6

[0081] An intermediate paint coating for enhancing electromagnetic shielding, the coating comprises the following raw materials by mass fraction: 48 parts of epoxy resin, 0.6 parts of MOF Ni3(HITP)2, 2 parts of TiNbAlC MAX phase ceramic material, 0.4 parts of soybean oil amidopropyl betaine, 2 parts of potassium magnesium fluorosilicate, 9 parts of conductive mica powder, 6 parts of whisker carbon nanotube, 4 parts of silver-coated copper conductive powder, 2 parts of leveling agent, 1 part of defoaming agent, 1 part of ultraviolet absorber, 1 part of hindered phenolic antioxidant, 1 part of phosphite antioxidant, 3 parts of aziridine crosslinking agent, 0.5 parts of hydroxyethyl cellulose, 24 parts of butanol.

[0082] The leveling agent is BYK-358N leveling agent. The defoaming agent is TEGO Foamex 810 defoaming agent. The ultraviolet absorber is Ciba UV-326 ultraviolet absorber. The hindered phenolic antioxidant is Ciba Irgafos 168 antioxidant. The phosphite antioxidant is Ciba Ultranox 626 antioxidant.

[0083] The above-mentioned preparation method of the intermediate paint coating for enhancing electromagnetic shielding, comprising the following steps:

[0084] S1: According to the mass fraction, soybean oil amidopropyl betaine and defoaming agent are added to 50wt% solvent, and mixed at 500 r / min for 10 min, then MOF Ni3(HITP)2 is added, and mixed at 1000 r / min for 20 min, to obtain material A;

[0085] S2: According to the mass fraction, TiNbAlC MAX phase ceramic material and whisker carbon nanotube are airflow mixed for 50 min, then silver-coated copper conductive powder is added and airflow mixed for 30 min, then potassium magnesium fluorosilicate and conductive mica powder are added and airflow mixed for 30 min, to obtain material B;

[0086] S3: Hydroxyethyl cellulose was added into the remaining 50 wt% solvent according to the mass fraction, and was uniformly premixed and dissolved to obtain material C;

[0087] S4: The leveling agent was added into material A according to the mass fraction, and was uniformly mixed at 600 r / min for 10 min. Then material B was added, and was uniformly mixed at 800 r / min for 15 min. Then aziridine crosslinking agent was added, and was uniformly mixed at 800 r / min for 20 min. Then epoxy resin, ultraviolet absorber, hindered phenol antioxidant and phosphite antioxidant were added, and were uniformly mixed at 1200 r / min for 25 min. Finally, material C was added, and was uniformly mixed at 800 r / min for 10 min to obtain the coating.

[0088] The coating prepared in this example was used as an intermediate paint for enhancing electromagnetic shielding property.

[0089] In each of the above examples: the epoxy resin was E-54 (616) with a viscosity of 6500 mPa·s, and was obtained from Wuxi Qian Guang Chemical Raw Material Co., Ltd.; the MOF Ni3(HITP)2had a length range of 400 nm-1 μm and a diameter range of 19-26 nm, and was obtained from Jiangsu Xianfeng Nanometer Material Technology Co., Ltd.; the TiNbAlC MAX phase ceramic material had a flake diameter range of 2 μm-30 μm, and was obtained from Jiangsu Xianfeng Nanometer Material Technology Co., Ltd.; the soybean oil amide propyl betaine was obtained from Shanghai Yuyu New Material Technology Co., Ltd.; the potassium magnesium fluosilicate had a particle size range of less than 800 mesh, and was obtained from Shanghai Gaoming Chemical Co., Ltd.; the conductive mica powder had a particle size range of less than 800 mesh, and was obtained from Lingshou County Husky Mineral Product Processing Factory; the whisker carbon nanotube had a length range of 2 μm-15 μm and an outer diameter range of 20 nm-200 nm, and was obtained from Jiangsu Xianfeng Nanometer Material Technology Co., Ltd.; the silver-coated copper conductive powder had a particle size range of less than 18 μm, and was PA30E, obtained from Shenzhen Xinfeng Technology Co., Ltd.; the aziridine crosslinking agent was HT-100, obtained from Guangzhou Hui Chu New Material Co., Ltd.; and the hydroxyethyl cellulose was C-178, obtained from Guangdong Zhongke Hongtai New Material Co., Ltd.

[0090] Comparative Example 1

[0091] MOF Ni3(HITP)2was not added in the coating, and the content of MOF Ni3(HITP)2was replaced by epoxy resin; other parameters and methods were the same as in Example 1.

[0092] Comparative Example 2

[0093] The TiNbAlC MAX phase ceramic material is not added in the coating, and the content of the TiNbAlC MAX phase ceramic material is replaced by epoxy resin; other parameters and methods are the same as in Example 1.

[0094] Comparative Example 3

[0095] The MOF Ni3(HITP)2 and the TiNbAlC MAX phase ceramic material are not added in the coating, and the contents of the MOF Ni3(HITP)2 and the TiNbAlC MAX phase ceramic material are replaced by epoxy resin; other parameters and methods are the same as in Example 1.

[0096] Comparative Example 4

[0097] The whisker carbon nanotube is not added in the coating, and the content of the whisker carbon nanotube is replaced by epoxy resin; other parameters and methods are the same as in Example 1.

[0098] Comparative Example 5

[0099] The soybean oil amide propyl betaine is not added in the coating, and the content of the soybean oil amide propyl betaine is replaced by epoxy resin; other parameters and methods are the same as in Example 1.

[0100] Comparative Example 6

[0101] Preparation method: hydroxyethyl cellulose is added to 50wt% solvent, pre-mixed and dissolved uniformly to obtain a hydroxyethyl cellulose solution; the remaining all raw materials are mixed at 1000r / min for 150min, then the hydroxyethyl cellulose solution is added and mixed for 20min to obtain the coating.

[0102] The coatings of the above examples and comparative examples are detected.

[0103] Sample: The coating object material is a plastic plate, and the middle paint (the coating of each example and comparative example) is directly coated on the insulating plastic plate with a coating thickness of 160μm.

[0104] I. After the coating is dried and cured, whether the surface state of the coating is flat, bubble-free, and free of defects such as sagging is observed, and the results are shown in Table 1 below.

[0105] II. Conductivity:

[0106] According to GB / T 35033 "30MHz-1GHz Electromagnetic Shielding Material Conductivity and Metal Material Lapping Impedance Measurement Method". The resistance value of the coating is directly measured using a resistance box, and then the conductivity is calculated according to the size and shape of the sample, and the results are shown in Table 1 below.

[0107] III. Adhesion:

[0108] According to GB / T 9286 "Paints and varnishes Cross-hatch adhesion test", uniform speed cross-hatch on the coating, the coating is broken to form a grid of a specified size, 2mm x 2mm square, and the cross-hatch must penetrate the coating to the substrate. Paste the tape on the cross-hatch area to ensure that the tape is tightly attached to the coating without bubbles. Quickly and violently tear the tape at a 45° angle, repeat 3 times. Observe the peeling of the coating, and the adhesion rating is shown in Table 1 according to the standard.

[0109] Four, weather resistance:

[0110] According to GB / T 1865-2009 "Paints and varnishes Artificial weathering and artificial radiation exposure Filtered xenon arc radiation", xenon lamp aging test: put the test plate into the xenon lamp aging test box, control the irradiance at 340nm wavelength, set the irradiance value to 0.51W / m², set the blackboard temperature to 65℃, the temperature in the test box during the light stage is 50℃; the temperature in the dark stage is 20℃, the relative humidity is 55%. The rainfall time is 10min, the stop rain time is 4h, the spray pressure of the rainfall is controlled at 0.15MPa, the quality of the rainfall water is distilled water, after 2000 hours of testing, the conductivity and adhesion are detected, and the results are shown in Table 1.

[0111] Table 1 Appearance, conductivity, adhesion and weather resistance test results

[0112]

[0113] Five, electromagnetic shielding effectiveness:

[0114] According to GB / T 25471 "Measurement method of shielding effectiveness of electromagnetic shielding coatings", test the shielding effectiveness of electromagnetic shielding coatings for plane electromagnetic waves; place the prepared sample in the test fixture of the vector network analyzer, set the parameters of the test equipment according to the test requirements of the high frequency band: A-frequency 1GHz, scan point number 500 points, bandwidth 100MHz; B-frequency 4GHz, scan point number 500 points, bandwidth 200MHz; C-frequency 6GHz, scan point number 500 points, bandwidth 300MHz; D-frequency 10GHz, scan point number 500 points, bandwidth 400MHz; E-frequency 18GHz, scan point number 500 points, bandwidth 500MHz. By measuring the power change, phase change and other parameters of electromagnetic waves before and after passing through the sample, the initial electromagnetic shielding effectiveness of the sample is calculated, and the results are shown in Table 2.

[0115] During test four, simultaneously prepare the aged sample for detecting electromagnetic shielding effectiveness, detect the electromagnetic shielding effectiveness after aging, and the results are shown in Table 2.

[0116] Table 2 Electromagnetic shielding effectiveness and weather resistance electromagnetic shielding effectiveness test results

[0117]

[0118] From the results of Table 1 and Table 2 above, it can be seen that the coatings of Examples 1 to 6 have excellent electromagnetic shielding ability, conductive ability, and good anti-aging property, and the electromagnetic shielding effect is stable. From the results of Comparative Examples 1 to 3, it can be seen that the addition of MOF Ni3(HITP)2or TiNbAlC MAX phase ceramic material in the coating will affect the electromagnetic shielding ability, conductive ability of the coating to different degrees, and the stability of the magnetic shielding effect after aging decreases; at the same time, without the addition of MOF Ni3(HITP)2and TiNbAlC MAX phase ceramic material, the electromagnetic shielding ability, conductive ability, and stability of the magnetic shielding effect after aging of the coating decrease significantly. From the results of Comparative Example 4, it can be seen that the addition of whisker carbon nanotubes in the coating will decrease various performances. From the results of Comparative Example 5, it can be seen that the addition of soybean oil amide propyl betaine in the coating will affect the uniformity of the preparation of the coating, resulting in bubbles and sagging in the coating layer, poor uniformity, weak parts, affecting the electromagnetic shielding ability, conductive ability, and poor anti-aging property, and the electromagnetic shielding effect is relatively unstable. From the results of Comparative Example 6, it can be seen that in the preparation method, hydroxyethyl cellulose is added to 50wt% solvent, pre-mixed and dissolved uniformly to obtain a hydroxyethyl cellulose solution; the remaining all raw materials are mixed at 1000r / min for 150min, then the hydroxyethyl cellulose solution is added and mixed for 20min to obtain the coating; changing the preparation method will result in bubbles and sagging in the coating layer, poor uniformity, weak parts, affecting the electromagnetic shielding ability, conductive ability, and poor anti-aging property, and the electromagnetic shielding effect is relatively unstable.

Claims

1. An intermediate paint coating for enhancing electromagnetic shielding properties, characterized by, The coating comprises the following raw materials by mass fraction: 40-50 parts of epoxy resin, 0.3-0.8 parts of MOF Ni3(HITP)2, 1-3 parts of TiNbAlC MAX phase ceramic material, 0.3-0.5 parts of soybean oil amidopropyl betaine, 2-5 parts of potassium magnesium fluosilicate, 8-12 parts of conductive mica powder, 5-10 parts of whisker carbon nanotube, 3-5 parts of silver-coated copper conductive powder, 1-2 parts of leveling agent, 1-2 parts of defoaming agent, 1-2 parts of ultraviolet absorber, 1-1.5 parts of hindered phenolic antioxidant, 0.5-1 part of phosphite antioxidant, 2-5 parts of aziridine crosslinking agent, 0.5-1.5 parts of hydroxyethyl cellulose, 20-30 parts of solvent; The MOF Ni3(HITP)2 has a size of 400 nm-1 μm in length and 19-26 nm in diameter; the TiNbAlC MAX phase ceramic material has a size of 2 μm-30 μm in flake diameter; and the whisker carbon nanotube has a size of 2 μm-15 μm in length and 20 nm-200 nm in outer diameter; The preparation method of the coating comprises the following steps: S1: according to mass fraction, soybean oil amidopropyl betaine and defoaming agent are added into 50 wt% solvent, mixed uniformly, then MOF Ni3(HITP)2 is added and mixed uniformly, to obtain material A; S2: according to mass fraction, TiNbAlC MAX phase ceramic material and whisker carbon nanotube are air-flow mixed uniformly, then silver-coated copper conductive powder is added and air-flow mixed uniformly, then potassium magnesium fluosilicate and conductive mica powder are added and air-flow mixed uniformly, to obtain material B; S3: according to mass fraction, hydroxyethyl cellulose is added into the remaining 50 wt% solvent, pre-mixed and dissolved uniformly, to obtain material C; S4: according to mass fraction, leveling agent is added into material A and mixed uniformly, then material B is added and mixed uniformly, then aziridine crosslinking agent is added and mixed uniformly, then epoxy resin, ultraviolet absorber, hindered phenolic antioxidant and phosphite antioxidant are added and mixed uniformly, finally material C is added and mixed uniformly, to obtain the coating.

2. The intermediate coating paint for enhancing electromagnetic shielding property according to claim 1, characterized by, The potassium magnesium fluosilicate has a particle size of less than 800 mesh.

3. The intermediate coating paint for enhancing electromagnetic shielding property according to claim 1, characterized by, The conductive mica powder has a particle size of less than 800 mesh.

4. The intermediate coating paint for enhancing electromagnetic shielding property according to claim 1, characterized by, The silver-coated copper conductive powder has a particle size of less than 18 μm.

5. The intermediate coating paint for enhancing electromagnetic shielding property according to claim 1, wherein The leveling agent is BYK-333 leveling agent, BYK-358N leveling agent, TEGO Glide 410 leveling agent or TEGO Flow 370 leveling agent; the defoaming agent is BYK-066N defoaming agent, BYK-024 defoaming agent, TEGO Foamex 810 defoaming agent or TEGO Airex 902W defoaming agent; the ultraviolet light absorber is Tinuvin P ultraviolet light absorber, Tinuvin 1577 ultraviolet light absorber, Ciba UV-326 ultraviolet light absorber or Ciba UV-1164 ultraviolet light absorber; the hindered phenol antioxidant is Irganox 1010 antioxidant or Ciba Irgafos 168 antioxidant; the phosphite antioxidant is Irgafos 126 antioxidant or Ciba Ultranox 626 antioxidant; the solvent is butanol.

6. Use of an intermediate coating paint for enhancing electromagnetic shielding properties according to claim 1, characterized in that, The coating is used as an intermediate paint for enhancing electromagnetic shielding properties.

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