CN112638143A - Efficient electromagnetic shielding nano silver paste and preparation method thereof - Google Patents
Efficient electromagnetic shielding nano silver paste and preparation method thereof Download PDFInfo
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- CN112638143A CN112638143A CN202011547381.7A CN202011547381A CN112638143A CN 112638143 A CN112638143 A CN 112638143A CN 202011547381 A CN202011547381 A CN 202011547381A CN 112638143 A CN112638143 A CN 112638143A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/20—Conductive material dispersed in non-conductive organic material
- H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
Abstract
The invention relates to the technical field of electromagnetic shielding slurry, and discloses high-efficiency electromagnetic shielding nano silver paste and a preparation method thereof, wherein the nano silver paste comprises the following components in percentage by mass: 30-80% of nano silver powder, 15-65% of solvent, 0.5-3% of crosslinking assistant and 0.01-2.0% of accelerator, wherein the nano silver powder is modified by surface modification through functional siloxane. The invention also discloses a preparation method of the high-efficiency electromagnetic shielding nano silver paste, which is characterized in that a reactive micromolecule siloxane is modified on the surface of the nano silver powder through molecular design, and then the bonding of the coating, the base material and the silver powder can be realized without adding any polymer by utilizing the reaction characteristic of hydrolytic condensation and crosslinking of the siloxane groups on the surface. Meanwhile, the nano silver paste with high conductivity, high shielding effectiveness and high reliability is prepared by utilizing the low-temperature sintering characteristic of the nano silver, the adhesion can reach 5B, the shielding effectiveness of the material is more than 80dB, and the nano silver paste is used for conformal shielding of a system-in-package device and a PCB (printed Circuit Board) level.
Description
Technical Field
The invention relates to the technical field of electromagnetic shielding slurry, in particular to high-efficiency electromagnetic shielding nano silver paste and a preparation method thereof.
Background
With the rapid development of scientific technology and electronic information industry, various digital and high-frequency electronic and electrical equipment such as computers and radio communication equipment are continuously popularized and applied, so that new vitality is injected into the information industry revolution, the development of industrial technology is promoted, and the life of people is improved. However, these electronic devices radiate a large number of electromagnetic waves of different wavelengths and frequencies into space due to rapid voltage changes during operation, and these electromagnetic radiations not only interfere with the propagation of signals of various electronic systems for communication but also may cause information leakage in digital transmission systems, posing a threat to national information and security. In addition, the large dose of electromagnetic radiation can also affect the nervous system and the lymphatic system of the human body, so that the human body suffers from nervous diseases and malignant tumors, and the living environment of the human body can be harmed. With the application of electronic equipment, the interference of electromagnetic wave radiation on electrical appliances and electronic equipment is effectively inhibited, and people are increasingly paid more attention to the protection of human beings from the harm of electromagnetic wave radiation, so that the electromagnetic wave radiation-resistant electromagnetic wave shielding material becomes an important task for scientific research and industrial product development.
The most convenient and effective way to suppress electromagnetic radiation is to achieve electromagnetic shielding using shielding materials. The electromagnetic shielding material reflects electromagnetic waves through impedance difference with air and attenuates eddy currents of the electromagnetic waves through self electromagnetic induction. Due to the good electrical conductivity of metallic materials, the most common EMI shielding solution has traditionally been to use a metal cover or cage to cover the target area or component. However, this solution cannot meet the continuously increasing demands for miniaturization (thinner and thinner packages), smaller footprint (footprint) and higher packing density of electronic components. This solution cannot be used in some micro devices, since the metal cover/lid requires too much space. Particularly, with the arrival of the high-frequency and high-speed 5G era and the development of wearable equipment, electronic components are developing towards miniaturization, light weight, digitalization and high-density integration, higher requirements are provided for electromagnetic shielding materials, and the novel shielding material should meet the characteristics of thinness, lightness, width, strength and the like, namely, the shielding material is thin in thickness, light in weight, wide in absorption frequency band and strong in wave absorption capacity under the same conditions. Therefore, research and development of novel electromagnetic shielding materials with high efficiency, easy use and high cost performance become key elements for treating space pollution and improving living environment. In the face of increasing social demands, the novel efficient electromagnetic shielding material has very remarkable social and economic benefits.
In recent years, in order to meet the ultra-thin requirement of the product and keep the same with the ultra-thin thickness of the product, the new generation of conformal shielding technology is increasingly emphasized. The leading technology for preparing the ultrathin shielding layer in the industry at present is mainly realized by three processes of sputtering, electroplating and spraying. The sputtering technique is a technique of bombarding the surface of a plating material with charged particles in a vacuum chamber to deposit the bombarded particles on a substrate. The prepared coating has uniform density, strong bonding force with a base material, controllable film thickness and good repeatability, but the target material has low utilization rate, complex equipment and high cost. In addition, the conformal shielding film prepared by the technology in the SIP package structure has some problems, such as poor bonding with EMC; the limited sidewall coating results in low coverage (< 50%), which may lead to poor shield grounding and reliable performance; low processing speed, low mass production efficiency and the like. The plating technique is a technique of forming a plating layer by depositing cations of a pre-plated metal in a plating solution on a substrate surface by electrolysis using a metal to be plated as a cathode in a salt solution containing the pre-plated metal. The method is not limited by the shape and size of the base material, the coating is uniform and has strong adhesive force, and the method can be used for batch production and has low cost. The disadvantage is that the varieties of plastics suitable for electroplating are few, and the plastics must be subjected to special activation and sensitization treatment before electroplating. More critically, the process requires soaking the SIP device in an electrolyte, which may increase the potential for later failure of the device. Further, the plating technique is not recognized due to environmental requirements and the like. The spray coating technique is a coating technique in which a liquid is atomized into a mist by an air flow of compressed air and sprayed on the surface of an object to form a thin film. Compared with the two technologies, the technology has the advantages of relatively low capital investment, simple and convenient operation, good coating quality, high coating efficiency and the like. The conformal shielding process can flexibly meet various requirements of a single-layer chip, and has excellent adhesive property and reliability, simple and clean process and low investment cost. Therefore, the technology is considered to be an attractive solution, which is concerned and favored by back-end application manufacturers.
The traditional electromagnetic shielding paste is mainly additive type, namely prepared by compounding polymer and conductive powder. For example, Chinese patent CN2917207Y discloses an environment-friendly conductive material for electromagnetic shielding, which is prepared by compounding low-bulk-ratio flaky composite metal conductive powder with polymer film-forming resin and the like to prepare a shielding coating layer with the thickness of 8-15 um and the electrical sheet resistance of 150m omega/□. The method can only make the electrical property of the prepared coating reach 10 due to the existence of the polymer-4～10-5And the shielding requirement of SIP packaging cannot be met. Subsequently, CN102321402A discloses a transparent conductive ink composed of organic amine or ammonia water as solvent and organic silver salt, wherein a surfactant or an adhesive is added according to the affinity and adhesiveness of the substrate when the conductive ink is used, and then the conductive ink is heated and cured at 90-200 ℃ to obtain a conductive circuit. Although the method does not need to add a protective agent, organic amine or ammonia water is adopted as a solvent, and organic silver salt and the like need to be prepared in advance, so that the method is complex and the stability of the organic silver salt is poor; in addition, fatty alcohol or other substances are added to adjust the viscosity of the ink according to the characteristics of different substrates during use, so that the ink is inconvenient to use and has poor bonding force with the substrates, and the addition of the substances still has the defects of influence on the final conductivity and poor surface flatness of the wires. CN104140717A discloses a high-solid-content spray printing conductive ink with good dispersibility and high stability, which can be sintered at low temperature and has conductivity reaching 9.1-40.2 m omega/□ after molding, but because the high-molecular-weight viscosity regulator used in the system is hydrophilic resin, the adhesion capability and the humidity and heat resistance performance of the high-molecular-weight viscosity regulator cannot reach the use standard of the electronic industry.
Disclosure of Invention
Aiming at overcoming the defects of the prior art, the invention provides the high-efficiency electromagnetic shielding nano silver paste and the preparation method thereof, aiming at EMI interference around and inside system-in-package (SIP) and high conductivity, high shielding efficiency and high reliability requirements on shielding paste. Meanwhile, the nano silver paste with high conductivity, high shielding efficiency and high reliability is prepared by utilizing the low-temperature sintering characteristic of the nano silver, the adhesive force can reach 5B, the sheet resistance is small by 10m omega/□, and the shielding efficiency of the coating is larger than 80 dB. And for system-in-package device and PCB board level conformal shielding.
The first purpose of the invention is to provide an efficient electromagnetic shielding nano silver paste, which comprises the following components in percentage by mass:
30-80% of nano silver powder;
15-65% of a solvent;
0.5-3% of a crosslinking assistant;
0.01-2.0% of an accelerator;
the nano silver powder is modified by surface modification through functional siloxane.
In the technical scheme of the invention, the shape of the nano silver powder is selected from one or more of sheet shape, spherical shape/sphere-like shape, cube, triangle and rod shape, and the size is 5-100 nm; preferably 5-60 nm sphere-like nano silver powder.
According to the technical scheme, the surface modification method of the nano silver powder comprises the steps of adding an alcoholic solution of the nano silver powder into an alcoholic solution of functional siloxane and organic acid, performing ultrasonic dispersion, washing, filtering and drying to obtain the modified nano silver powder.
In the technical scheme of the invention, the mass ratio of the nano silver powder, the functional siloxane and the organic acid is 100: 1-10: 0.5 to 10.
In the technical scheme, the alcoholic solution of the nano silver powder is obtained by dispersing the nano silver powder in an alcohol solvent, and the mass fraction of the nano silver powder is 5-50%;
preferably, the alcohol solution of the functional siloxane and the organic acid is obtained by dispersing the functional siloxane and the organic acid in an alcohol solvent, wherein the mass fraction of the functional siloxane is 1-10%; the mass fraction of the organic acid is 0.5-10%;
preferably, the alcohol solvent is selected from one of ethanol, methanol or isopropanol;
preferably, the ultrasonic dispersion condition is ultrasonic dispersion for 5-60 min at 25-60 ℃;
preferably, the drying condition is room temperature, and the vacuum drying time is more than or equal to 24 hours.
In the technical scheme of the invention, the functional siloxane for surface modification of the nano silver powder is selected from one or more of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, gamma- (ethylenediamine) propyltrimethoxysilane, N- (beta-aminoethyl) -gamma-aminopropylmethyldimethoxysilane, gamma- (ethylenediamine) propyltriethoxysilane, N- (beta-aminoethyl) -gamma-aminopropylmethyldiethoxysilane, phenylamino trimethoxysilane, phenylamino triethoxysilane, mercaptopropylmethyldimethoxysilane, mercaptopropyltrimethoxysilane, mercaptopropylmethyldiethoxysilane and mercaptopropyltriethoxysilane, the organic acid is selected from one or more of isooctanoic acid, octanoic acid, decanoic acid, neodecanoic acid and oleic acid, the functional siloxane is preferably aminopropyltriethoxysilane, the organic acid is preferably neodecanoic acid.
In the technical scheme of the invention, the solvent is one or more selected from ethanol, isopropanol, butanol, acetone, butanone, cyclohexanone, tetrahydrofuran, toluene, xylene, diethylbenzene, terpineol, propylene glycol methyl ether, propylene glycol ethyl ether, diethylene glycol methyl ether, dipropylene glycol methyl ether, diethylene glycol ethyl ether, dipropylene glycol ethyl ether, diethylene glycol butyl ether, dipropylene glycol butyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, ethylene glycol phenyl ether, propylene glycol methyl ether acetate, propylene glycol butyl ether acetate, triethylene glycol monomethyl ether, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, preferably propylene glycol methyl ether and ethylene glycol ethyl ether acetate.
In the technical scheme of the invention, the crosslinking assistant is selected from dimethyl dimethoxy silane, dimethyl diethoxy silane, diethyl dimethoxy silane, diethyl diethoxy silane, dipropyl dimethoxy silane, dipropyl diethoxy silane, methyl vinyl dimethoxy silane, methyl ethyl dimethoxy silane, methyl phenyl dimethoxy silane, methyl cyclohexyl dimethoxy silane, methyl vinyl diethoxy silane, methyl ethyl diethoxy silane, methyl phenyl diethoxy silane, methyl cyclohexyl diethoxy silane, diphenyl dimethoxy silane, diphenyl diethoxy silane, methyl trimethoxy silane, methyl triethoxy silane, ethyl trimethoxy silane, ethyl triethoxy silane, propyl trimethoxy silane, propyl triethoxy silane, isopropyl trimethoxy silane, isopropyl triethoxy silane, methyl ethyl diethoxy silane, methyl n-butyl diethoxy silane, methyl n-, One or more of vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and hydroxy silicone oil, preferably ethyltriethoxysilane and methylphenyldimethoxysilane.
In the technical scheme of the invention, the accelerant is one or more selected from stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, bismuth isooctanoate, bismuth laurate, bismuth neodecanoate, bismuth naphthenate, zinc naphthenate and zinc isooctanoate, and dibutyltin dilaurate is preferred.
The second purpose of the invention is to provide a preparation method of the high-efficiency electromagnetic shielding nano silver paste, which comprises the following steps:
s1, weighing the raw materials according to the components and the content of the nano silver paste for electromagnetic shielding, dispersing the nano silver powder in ethanol, dispersing the nano silver powder uniformly by ultrasonic, adding an ethanol solution of functional siloxane and organic acid, dispersing the mixture by ultrasonic, washing, filtering and drying to obtain the functional siloxane modified nano silver powder;
s2, uniformly mixing the modified nano silver powder, the crosslinking assistant, the accelerant and the solvent to obtain a mixed material;
and S3, grinding, filtering and defoaming the mixed material to obtain the high-efficiency electromagnetic shielding nano silver paste.
Compared with the prior art, the invention has the following beneficial effects:
(1) according to the requirements of the spraying process, the surface of the nano silver powder is modified from the aspect of molecular design, and the good bonding force between the coating and the EMC substrate can be formed without adding any polymer through the grafting of reactive micromolecule siloxane and the reaction characteristic of hydrolytic condensation crosslinking. Meanwhile, the blocking of the non-conductive polymer organic carrier on the contact and sintering between the nano particles is effectively avoided, the contact probability between the nano silver powder is obviously improved, and the contact resistance of a cured substance is reduced.
(2) According to the invention, reactive micromolecular siloxane is combined with organic acid, so that the dispersibility of the nano-silver is effectively improved; meanwhile, the alcohol solvent is matched, so that the hydrolysis of siloxane groups is remarkably inhibited, and the stability of the nano silver paste is greatly improved, thereby solving the problems of sedimentation and unstable spraying process which are often caused by spraying of low-viscosity silver paste.
(3) According to the invention, the nano silver is used as the conductive particles, and low-temperature sintering can be realized at 120-170 ℃, so that a compact metal layer is formed, the interface contact resistance among the nano silver powder is obviously reduced, a high-reliability conductive network is obtained, and the method has important significance for preparing an ultrathin-layer high-performance electromagnetic shielding material.
(4) The high-performance electromagnetic shielding nano silver paste obtained by the invention has the conductivity of 4.2-6.5 multiplied by 10 after being cured-6(omega cm), adhesive force of 5B, and shielding effectiveness of 100 MHz-6 GHz material is greater than 80 dB.
Detailed Description
To better illustrate the invention and to facilitate the understanding of the technical solutions thereof, typical but non-limiting examples of the invention are as follows:
it should be noted that the silver powder size involved in the present invention refers to the particle size, and the nano silver powder is directly purchased from Ningbo Jinlei nano material science and technology company and gold new material science and technology company of Foshan City; in the following examples, aminopropyltriethoxysilane, propylene glycol monomethyl ether, terpineol, methylphenyldimethoxysilane, dibutyltin dilaurate, bismuth isooctanoate, neodecanoic acid, isooctanoic acid, etc. were all analytical grade and were purchased from Aladdin reagents, Inc.
Example 1
The efficient electromagnetic shielding nano silver paste comprises the following components in parts by mass:
JL NANO-20 Nano silver (Nano silver powder): 70g
Propylene glycol methyl ether (solvent): 14g
Diethylene glycol butyl ether (solvent): 15g of
Methylphenyldimethoxysilane (crosslinking aid): 1.0g
Dibutyl tin dilaurate (accelerator): 0.01.
the preparation method of the electromagnetic shielding nano silver paste comprises the following steps:
s1, modifying the surface of the nano silver powder: firstly, 70g of NANO silver powder (JL NANO-20) is dispersed in 395g of ethanol for 15min by ultrasonic dispersion, then 3.0g of aminopropyltriethoxysilane, 1.5g of neodecanoic acid and 40g of ethanol solution are mixed uniformly and added into the ethanol solution of the NANO silver powder, and ultrasonic dispersion is carried out for 30min at room temperature; and finally, washing, filtering and vacuum drying at room temperature for 24 hours to obtain the functional siloxane modified nano silver powder.
S2, weighing the raw materials according to the components and the content of the high-efficiency electromagnetic shielding nano silver paste, and uniformly mixing the modified nano silver powder obtained in the step S1, methyl phenyl dimethoxy silane, dibutyl tin dilaurate, propylene glycol monoether and diethylene glycol monobutyl ether; finally grinding, filtering and defoaming to obtain the high-efficiency electromagnetic shielding nano silver paste 1, and testing to obtain the coating with the thickness of 10um and the volume resistivity of 4.2 to 10 after the electromagnetic shielding silver paste 1 is cured-6Omega cm, shielding effectiveness 88 dB.
Example 2
The efficient electromagnetic shielding nano silver paste comprises the following components in parts by mass:
JL NANO-20 Nano silver (Nano silver powder): 65g of
Propylene glycol methyl ether (solvent): 22g
Terpineol (solvent): 11g
Methylphenyldimethoxysilane (crosslinking aid): 2.0g
Dibutyltin dilaurate (accelerator): 0.01g
The preparation method of the electromagnetic shielding nano silver paste comprises the following steps:
s1, modifying the surface of the nano silver powder: firstly, 65g of NANO silver powder (JL NANO-20) is dispersed in 685g of ethanol for 15min by ultrasonic dispersion, then 3.0g of aminopropyltriethoxysilane, 1.5g of neodecanoic acid and 79g of ethanol solution are added into the NANO silver ethanol solution, and ultrasonic dispersion is carried out for 30min at room temperature; and finally, washing, filtering and vacuum drying at room temperature for 24 hours to obtain the functional siloxane modified nano silver powder.
S2, weighing the raw materials according to the components and the content of the high-efficiency electromagnetic shielding nano silver paste, and uniformly mixing the modified nano silver powder obtained in the step S1, methyl phenyl dimethoxy silane, dibutyltin dilaurate, propylene glycol monomethyl ether and terpineol; finally grinding, filtering and defoaming to obtain the high-efficiency electromagnetic shielding nano silver paste 2, and testing to obtain the coating with the thickness of 10um and the volume resistivity of 5.1 to 10 after the electromagnetic shielding silver paste 2 is cured-6Omega cm, shielding effectiveness 86 dB.
Example 3
The efficient electromagnetic shielding nano silver paste comprises the following components in parts by mass:
JL NANO-20 Nano silver (Nano silver powder): 50g
Butanol (solvent): 45g of
Terpineol (solvent): 14g
Dimethyl dimethoxy silane (crosslinking aid): 0.8g
Bismuth isooctanoate (accelerator): 0.2g
The preparation method of the electromagnetic shielding nano silver paste comprises the following steps:
s1, modifying the surface of the nano silver powder: firstly, 50g of NANO silver powder (JL NANO-20) is dispersed in 395g of ethanol for 15min by ultrasonic dispersion, then 2.5g of N- (beta-aminoethyl) -gamma-aminopropyltriethoxysilane, 2.0g of isooctanoic acid and 40g of ethanol solution are added into the NANO silver ethanol solution, and ultrasonic dispersion is carried out for 30min at room temperature; and finally, washing, filtering and vacuum drying at room temperature for 24 hours to obtain the functional siloxane modified nano silver powder.
S2, high-efficiency electricity according to the aboveWeighing the components and the content of the magnetic shielding nano silver paste respectively, and uniformly mixing the modified nano silver powder obtained in the step S1, dimethyl dimethoxy silane, bismuth isooctanoate, butanol and terpineol; finally grinding, filtering and defoaming to obtain the high-efficiency electromagnetic shielding nano silver paste 3, and testing to obtain the coating with the thickness of 6um and the volume resistivity of 4.8 to 10 after the electromagnetic shielding silver paste 3 is cured-6Omega cm, shielding effectiveness 87 dB.
Example 4
The efficient electromagnetic shielding nano silver paste comprises the following components in parts by mass:
JN NP-50 nanosilver (silver nanopowder): 65g of
Diethylene glycol butyl ether (solvent): 20g of
Terpineol (solvent): 14g
Dimethyl dimethoxy silane (crosslinking aid): 0.9g
Bismuth isooctanoate (accelerator): 0.1g
The preparation method of the electromagnetic shielding nano silver paste comprises the following steps:
s1, modifying the surface of the nano silver powder: firstly, 65g of nano silver powder (JN NP-50) is dispersed in 395g of ethanol for 15min by ultrasonic dispersion, then 3.0g of aminopropyltriethoxysilane, 1.5g of neodecanoic acid and 40g of ethanol solution are added into the nano silver ethanol solution, and ultrasonic dispersion is carried out for 30min at room temperature; and finally, washing, filtering and vacuum drying at room temperature for 24 hours to obtain the functional siloxane modified nano silver powder.
S2, weighing the raw materials according to the components and the content of the high-efficiency electromagnetic shielding nano silver paste, and uniformly mixing the modified nano silver powder obtained in the step S1, dimethyl dimethoxy silane, bismuth isooctanoate, diethylene glycol monobutyl ether and terpineol; finally grinding, filtering and defoaming to obtain the high-efficiency electromagnetic shielding nano silver paste 4, and testing to obtain the coating with the thickness of 10um and the volume resistivity of 5.6 to 10 after the electromagnetic shielding silver paste 4 is cured-6Ω · cm, shielding effectiveness 84 dB.
Example 5
The efficient electromagnetic shielding nano silver paste comprises the following components in parts by mass:
JN NP-50 nanosilver (silver nanopowder): 30g of
Terpineol (solvent): 22g
Diethylene glycol monobutyl ether acetate (solvent): 45g of
Phenyltrimethoxysilane (crosslinking aid): 3.0 g;
bismuth neodecanoate (promoter): 0.05 g.
The preparation method of the electromagnetic shielding nano silver paste comprises the following steps:
s1, surface modification of the nano silver powder: firstly, dispersing 30g of nano silver powder (JN NP-50) in 395g of ethanol for 15min by ultrasonic dispersion, then adding 2.0g of aminopropyltriethoxysilane, 1.0g of neodecanoic acid and 40g of ethanol solution into the nano silver ethanol solution, and dispersing for 30min by ultrasonic dispersion at room temperature; and finally, washing, filtering and vacuum drying at room temperature for 24 hours to obtain the functional siloxane modified nano silver powder.
S2, weighing the raw materials according to the components and the content of the high-efficiency electromagnetic shielding nano silver paste, and uniformly mixing the modified nano silver powder obtained in the step S1, the crosslinking assistant, the accelerant and the solvent; finally grinding, filtering and defoaming to obtain the high-efficiency electromagnetic shielding nano silver paste 5, and testing to obtain the coating with the thickness of 5um and the volume resistivity of 6.5 to 10 after the electromagnetic shielding silver paste 5 is cured-6Omega cm, shielding effectiveness 80 dB.
Comparative example 1
Comparative example 1 is a conventional electromagnetic shielding paste in which modified nitrile rubber is directly purchased, and is different from example 1 in that the electromagnetic shielding paste of comparative example 1 comprises the following components in parts by weight:
the preparation method comprises the following steps:
firstly, weighing stoichiometric epoxy resin and modified nitrile rubber in turn, and mixing the stoichiometric epoxy resin and the modified nitrile rubberDissolving in a solvent, adding silver powder, dispersing uniformly, and standing at normal temperature for 24 h; then adding the curing agent, the curing accelerator and the residual solvent in sequence, and mixing uniformly; finally, grinding, filtering and vacuum defoaming are carried out, so as to obtain the comparative electromagnetic shielding silver paste 1, and through testing, the viscosity 470cps and the volume resistivity 1.0 x 10 of the comparative electromagnetic shielding silver paste 1 are obtained-4Omega cm, shielding effectiveness 70 dB.
Comparative example 2
Comparative example 2 is a conventional electromagnetic shielding paste, and is different from example 1 in that the sprayable electromagnetic shielding paste comprises the following components in parts by weight:
e51 epoxy resin 70 parts
DEN439 novolac epoxy resin 30 parts
30 portions of E100 arylamine curing agent
0.6 part of 2-ethyl-4-methylimidazole curing accelerator
1200 parts of silver powder (flake, 1-3 um)
Terpineol solvent 100 parts
650 parts of ethyl carbitol acetate solvent.
The preparation method comprises the following steps:
firstly, weighing stoichiometric epoxy resin in sequence, dissolving the stoichiometric epoxy resin in a solvent, then adding silver powder to disperse the silver powder uniformly, and standing the mixture at normal temperature for 24 hours; then adding the curing agent, the curing accelerator and the residual solvent in sequence, and mixing uniformly; finally, grinding, filtering and vacuum defoaming are carried out, so as to obtain the comparative electromagnetic shielding silver paste 2, and the viscosity 430cps and the volume resistivity 4.6 x 10 of the comparative electromagnetic shielding silver paste 2 are tested-5Ω · cm, shielding effectiveness 73 dB.
Performance testing
The electromagnetic shielding slurry prepared in the examples and comparative examples was subjected to the following performance tests:
(1) determination of volume resistivity
Cleaning the slide glass with absolute ethyl alcohol, pasting an insulating adhesive tape, cutting the middle of the slide glass into a standard rectangle by a steel knife, and then smearing electromagnetic shielding slurry. And placing the coated slide glass into an oven for curing. After solidification, after the electromagnetic shielding slurry is cooled, the thickness of the conductive film is measured by a micrometer, the width of the electromagnetic shielding slurry is measured by a vernier caliper, and the resistance is directly measured by a direct current digital resistance tester.
The volume resistivity was calculated according to the following formula (1).
In the formula: ρ -resistivity, Ω · cm;
r-measured resistance, Ω;
w is the width of the glue layer, cm;
t is the thickness of the adhesive layer, cm;
l is the length of the glue layer, cm.
Measuring the thickness of five places on each slide glass, and taking the average value; 5 samples were made for each formulation and the 5 resistivities were averaged.
(2) Determination of tensile shear Strength
The tensile shear strength was tested according to the requirements specified in GB7124-86 adhesive tensile shear Strength determination method, Metal to Metal, and loaded at a steady speed of (100 + -10) mm/min.
(3) Determination of Shielding Properties
The test frequency of the flange coaxial cavity is in the range of 30 MHz-20 GHz. The test method is to design a flange coaxial test device according to the requirements of electromagnetic shielding material shielding effectiveness measurement method GJB 6190-2008, wherein a cavity consists of an inner conductor and an outer conductor, the two conductors are separated, a sample is placed at the butt joint of the two cavities, the two parts of the cavity are connected through a flange and a nylon screw, and an N5230C network analyzer is used for testing the shielding effectiveness of an SIP shielding coating sample.
(4) Reliability test
PCT: pressure Cook book Test (Autoclave Test)
According to the JESD22-A102 standard, a sample to be tested is placed in a high-pressure cooking test box, and the test conditions are set to 130 ℃, 85% RH, Static bias, 15PSIG (2atm) and 96 h.
2. High and Low temperature impact Test (Thermal Shock Test)
According to the JESD22-A104-A standard, a sample to be tested is placed in a high-low temperature impact test, and the test conditions are set as follows: 1000 times at-55 ℃ to 125 ℃.
3. High Temperature Storage Test (High Temperature Storage Life Test)
According to the JESD22-A103-A standard, a sample to be tested is placed in a high-temperature storage test box, and the test conditions are set as follows: 150 ℃ and 1000 h.
The test results and conditions are shown in table 1:
TABLE 1 Performance test of electromagnetic shielding pastes obtained in examples 1 to 5 and comparative examples 1 to 2
Compared with the comparative examples 1 and 2, the stability of the slurry is obviously improved without layering and precipitation after the reactive micromolecular siloxane and the organic acid are adopted for modification in the formula of the electromagnetic shielding nano silver paste as shown in the table 1; and secondly, the cured shielding coating has excellent electrical performance which is more than 80dB, particularly, the shielding performance of the cured shielding coating can reach more than 85dB by adopting smaller nano silver, and meanwhile, the thinner and denser shielding coating can be obtained due to the sintering of the nano silver and passes a severe reliability test. Therefore, the technical scheme disclosed by the invention can obtain the ultrathin high-efficiency shielding coating and is used for conformal shielding of a system-in-package device and a PCB (printed circuit board).
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. The high-efficiency electromagnetic shielding nano silver paste is characterized in that: the composite material comprises the following components in percentage by mass:
30-80% of nano silver powder;
15-65% of a solvent;
0.5-3% of a crosslinking assistant;
0.01-2.0% of an accelerator;
the nano silver powder is modified by surface modification through functional siloxane.
2. The efficient electromagnetic shielding nano silver paste of claim 1, which is characterized in that: the shape of the nano silver powder is selected from one or more of sheet, spherical/sphere-like, cube, triangle and rod, and the size of the nano silver powder is 5-100 nm; preferably 5-60 nm sphere-like nano silver powder.
3. The efficient electromagnetic shielding nano silver paste of claim 1, which is characterized in that: the surface modification method of the nano silver powder comprises the steps of adding an alcoholic solution of the nano silver powder into an alcoholic solution of functional siloxane and organic acid, performing ultrasonic dispersion, washing, filtering and drying to obtain the modified nano silver powder.
4. The efficient electromagnetic shielding nano silver paste of claim 3, which is characterized in that: the mass ratio of the nano silver powder to the functional siloxane to the organic acid is 100: 1-10: 0.5 to 10.
5. The efficient electromagnetic shielding nano silver paste of claim 3, which is characterized in that: the alcoholic solution of the nano silver powder is obtained by dispersing the nano silver powder in an alcohol solvent, wherein the mass fraction of the nano silver powder is 5-50%;
preferably, the alcohol solution of the functional siloxane and the organic acid is obtained by dispersing the functional siloxane and the organic acid in an alcohol solvent, wherein the mass fraction of the functional siloxane is 1-10%; the mass fraction of the organic acid is 0.5-10%;
preferably, the alcohol solvent is selected from one of ethanol, methanol or isopropanol;
preferably, the ultrasonic dispersion condition is ultrasonic dispersion for 5-60 min at 25-60 ℃;
preferably, the drying condition is room temperature, and the vacuum drying time is more than or equal to 24 hours.
6. The functional siloxane surface-modified nanosilver of claim 3, wherein: the functional siloxane for surface modification of the nano silver powder is selected from one or more of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, gamma- (ethylenediamine) propyltrimethoxysilane, N- (beta-aminoethyl) -gamma-aminopropylmethyldimethoxysilane, gamma- (ethylenediamine) propyltriethoxysilane, N- (beta-aminoethyl) -gamma-aminopropylmethyldiethoxysilane, phenylamino trimethoxysilane, phenylamino triethoxysilane, mercaptopropylmethyldimethoxysilane, mercaptopropyltrimethoxysilane, mercaptopropylmethyldiethoxysilane and mercaptopropyltriethoxysilane, the organic acid is selected from one or more of isooctanoic acid, caprylic acid, capric acid, neodecanoic acid and oleic acid, the functional siloxane is preferably aminopropyltriethoxysilane, the organic acid is preferably neodecanoic acid.
7. The efficient electromagnetic shielding nano silver paste of claim 1, which is characterized in that: the solvent is one or more selected from ethanol, isopropanol, butanol, acetone, butanone, cyclohexanone, tetrahydrofuran, toluene, xylene, diethylbenzene, terpineol, propylene glycol methyl ether, propylene glycol ethyl ether, diethylene glycol methyl ether, dipropylene glycol methyl ether, diethylene glycol ethyl ether, dipropylene glycol ethyl ether, diethylene glycol butyl ether, dipropylene glycol butyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, ethylene glycol phenyl ether, propylene glycol methyl ether acetate, propylene glycol butyl ether acetate, triethylene glycol monomethyl ether, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, preferably propylene glycol methyl ether and ethylene glycol ethyl ether acetate.
8. The efficient electromagnetic shielding nano silver paste of claim 1, which is characterized in that: the crosslinking assistant is selected from dimethyl dimethoxy silane, dimethyl diethoxy silane, diethyl dimethoxy silane, diethyl diethoxy silane, dipropyl dimethoxy silane, dipropyl diethoxy silane, methyl vinyl dimethoxy silane, methyl ethyl dimethoxy silane, methyl phenyl dimethoxy silane, methyl cyclohexyl dimethoxy silane, methyl vinyl diethoxy silane, methyl ethyl diethoxy silane, methyl phenyl diethoxy silane, methyl cyclohexyl diethoxy silane, diphenyl dimethoxy silane, diphenyl diethoxy silane, methyl trimethoxy silane, methyl triethoxy silane, ethyl trimethoxy silane, ethyl triethoxy silane, propyl trimethoxy silane, propyl triethoxy silane, isopropyl trimethoxy silane, isopropyl triethoxy silane, vinyl trimethoxy silane, methyl diethoxy silane, methyl cyclohexyl dimethoxy silane, methyl phenyl dimethoxy silane, methyl cyclohexyl dimethoxy silane, ethyl trimethoxy silane, ethyl triethoxy silane, propyl, One or more of vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and hydroxysilicone oil, preferably ethyltriethoxysilane and methylphenyldimethoxysilane.
9. The efficient electromagnetic shielding nano silver paste of claim 1, which is characterized in that: the accelerant is one or more selected from stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, bismuth isooctanoate, bismuth laurate, bismuth neodecanoate, bismuth naphthenate, zinc naphthenate and zinc isooctanoate, and dibutyl tin dilaurate is preferred.
10. The preparation method of the high-efficiency electromagnetic shielding nano silver paste according to any one of claims 1 to 9, which is characterized by comprising the following steps:
s1, weighing the raw materials according to the components and the content of the nano silver paste for electromagnetic shielding, dispersing the nano silver powder in ethanol, dispersing the nano silver powder uniformly by ultrasonic, adding an ethanol solution of functional siloxane and organic acid, dispersing the mixture by ultrasonic, washing, filtering and drying to obtain the functional siloxane modified nano silver powder;
s2, uniformly mixing the modified nano silver powder, the crosslinking assistant, the accelerant and the solvent to obtain a mixed material;
and S3, grinding, filtering and defoaming the mixed material to obtain the high-efficiency electromagnetic shielding nano silver paste.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114505474A (en) * | 2022-01-26 | 2022-05-17 | 深圳先进电子材料国际创新研究院 | Multi-morphology low-temperature-sinterable nano-silver and preparation method and application thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103468159A (en) * | 2013-03-11 | 2013-12-25 | 苏州牛剑新材料有限公司 | Silver coated nickel powder conductive adhesive and preparation method thereof |
| CN105976893A (en) * | 2016-06-22 | 2016-09-28 | 中国科学院宁波材料技术与工程研究所 | Lead-free graphene/nano-silver composite electronic silver paste and preparation method thereof |
| CN110066633A (en) * | 2018-01-23 | 2019-07-30 | 中国科学院理化技术研究所 | A kind of preparation method of low silver content conducting resinl |
| CN110769678A (en) * | 2019-11-11 | 2020-02-07 | 北京中科纳通电子技术有限公司 | Electromagnetic shielding silver paste applied to 5G personal communication equipment and preparation method thereof |
-
2020
- 2020-12-24 CN CN202011547381.7A patent/CN112638143B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103468159A (en) * | 2013-03-11 | 2013-12-25 | 苏州牛剑新材料有限公司 | Silver coated nickel powder conductive adhesive and preparation method thereof |
| CN105976893A (en) * | 2016-06-22 | 2016-09-28 | 中国科学院宁波材料技术与工程研究所 | Lead-free graphene/nano-silver composite electronic silver paste and preparation method thereof |
| CN110066633A (en) * | 2018-01-23 | 2019-07-30 | 中国科学院理化技术研究所 | A kind of preparation method of low silver content conducting resinl |
| CN110769678A (en) * | 2019-11-11 | 2020-02-07 | 北京中科纳通电子技术有限公司 | Electromagnetic shielding silver paste applied to 5G personal communication equipment and preparation method thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114505474A (en) * | 2022-01-26 | 2022-05-17 | 深圳先进电子材料国际创新研究院 | Multi-morphology low-temperature-sinterable nano-silver and preparation method and application thereof |
| CN114505474B (en) * | 2022-01-26 | 2024-03-19 | 深圳先进电子材料国际创新研究院 | Multi-morphology low-temperature sinterable nano silver and preparation method and application thereof |
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