CN115197658B - Conductive adhesive for flexible printed circuit board and preparation method thereof - Google Patents
Conductive adhesive for flexible printed circuit board and preparation method thereof Download PDFInfo
- Publication number
- CN115197658B CN115197658B CN202210964368.4A CN202210964368A CN115197658B CN 115197658 B CN115197658 B CN 115197658B CN 202210964368 A CN202210964368 A CN 202210964368A CN 115197658 B CN115197658 B CN 115197658B
- Authority
- CN
- China
- Prior art keywords
- conductive
- conductive particles
- particles
- melting
- flexible printed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000000853 adhesive Substances 0.000 title claims abstract description 69
- 230000001070 adhesive effect Effects 0.000 title claims abstract description 69
- 238000002360 preparation method Methods 0.000 title claims abstract description 17
- 239000002245 particle Substances 0.000 claims abstract description 77
- 239000002923 metal particle Substances 0.000 claims abstract description 60
- 229910052751 metal Inorganic materials 0.000 claims abstract description 32
- 239000002184 metal Substances 0.000 claims abstract description 32
- 238000002156 mixing Methods 0.000 claims abstract description 25
- 229920005989 resin Polymers 0.000 claims abstract description 19
- 239000011347 resin Substances 0.000 claims abstract description 19
- 239000000956 alloy Substances 0.000 claims abstract description 16
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 16
- 239000011159 matrix material Substances 0.000 claims abstract description 13
- 238000000034 method Methods 0.000 claims abstract description 12
- 229920001940 conductive polymer Polymers 0.000 claims description 48
- 239000003822 epoxy resin Substances 0.000 claims description 21
- 229920000647 polyepoxide Polymers 0.000 claims description 21
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 18
- 238000002844 melting Methods 0.000 claims description 13
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 12
- 239000007822 coupling agent Substances 0.000 claims description 11
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 10
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 8
- 238000012986 modification Methods 0.000 claims description 7
- 230000004048 modification Effects 0.000 claims description 7
- 229920002635 polyurethane Polymers 0.000 claims description 7
- 239000004814 polyurethane Substances 0.000 claims description 7
- 238000001694 spray drying Methods 0.000 claims description 7
- 239000002904 solvent Substances 0.000 claims description 6
- 238000003756 stirring Methods 0.000 claims description 6
- 150000004645 aluminates Chemical group 0.000 claims description 4
- 239000003292 glue Substances 0.000 claims description 4
- 239000012046 mixed solvent Substances 0.000 claims description 4
- 229920000123 polythiophene Polymers 0.000 claims description 4
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 claims description 3
- 229920000877 Melamine resin Polymers 0.000 claims description 3
- 239000004640 Melamine resin Substances 0.000 claims description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 3
- 239000005011 phenolic resin Substances 0.000 claims description 3
- 229920001568 phenolic resin Polymers 0.000 claims description 3
- 229920001721 polyimide Polymers 0.000 claims description 3
- 239000009719 polyimide resin Substances 0.000 claims description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 2
- 229920000180 alkyd Polymers 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- SJCKRGFTWFGHGZ-UHFFFAOYSA-N magnesium silver Chemical compound [Mg].[Ag] SJCKRGFTWFGHGZ-UHFFFAOYSA-N 0.000 claims description 2
- 229920000767 polyaniline Polymers 0.000 claims description 2
- 229920000128 polypyrrole Polymers 0.000 claims description 2
- 239000002994 raw material Substances 0.000 claims description 2
- 229920002803 thermoplastic polyurethane Polymers 0.000 claims description 2
- 229920001187 thermosetting polymer Polymers 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 3
- 238000012545 processing Methods 0.000 abstract description 2
- 230000003014 reinforcing effect Effects 0.000 abstract description 2
- 239000011135 tin Substances 0.000 description 26
- 230000000052 comparative effect Effects 0.000 description 16
- 239000010949 copper Substances 0.000 description 11
- 239000000843 powder Substances 0.000 description 9
- 239000011230 binding agent Substances 0.000 description 7
- 239000000945 filler Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 5
- 239000012790 adhesive layer Substances 0.000 description 4
- 238000005452 bending Methods 0.000 description 4
- 238000000635 electron micrograph Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 229910052709 silver Inorganic materials 0.000 description 4
- 229910052718 tin Inorganic materials 0.000 description 4
- 239000004593 Epoxy Substances 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 3
- 239000011231 conductive filler Substances 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- XQUPVDVFXZDTLT-UHFFFAOYSA-N 1-[4-[[4-(2,5-dioxopyrrol-1-yl)phenyl]methyl]phenyl]pyrrole-2,5-dione Chemical compound O=C1C=CC(=O)N1C(C=C1)=CC=C1CC1=CC=C(N2C(C=CC2=O)=O)C=C1 XQUPVDVFXZDTLT-UHFFFAOYSA-N 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- KXDHJXZQYSOELW-UHFFFAOYSA-M Carbamate Chemical compound NC([O-])=O KXDHJXZQYSOELW-UHFFFAOYSA-M 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000004378 air conditioning Methods 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229920003192 poly(bis maleimide) Polymers 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 239000004945 silicone rubber Substances 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000013112 stability test Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000013008 thixotropic agent Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J9/00—Adhesives characterised by their physical nature or the effects produced, e.g. glue sticks
- C09J9/02—Electrically-conducting adhesives
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J163/00—Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/02—Elements
- C08K3/08—Metals
- C08K2003/0806—Silver
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/02—Elements
- C08K3/08—Metals
- C08K2003/0837—Bismuth
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/02—Elements
- C08K3/08—Metals
- C08K2003/085—Copper
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K2201/00—Specific properties of additives
- C08K2201/001—Conductive additives
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Adhesives Or Adhesive Processes (AREA)
- Conductive Materials (AREA)
Abstract
The invention belongs to the technical field of conductive adhesive, and discloses a conductive adhesive for a flexible printed circuit board and a preparation method thereof. The conductive adhesive comprises a resin matrix and low-melting-point metal conductive particles dispersed therein; the low-melting-point metal conductive particles are at least one metal particle in Sb, zn, pb, cd, bi, sn, in, ga. The conductive adhesive has good mixing processing performance with the resin matrix through the independently added low-melting-point metal conductive particles, can realize alloy in the bonding application process of the flexible printed circuit board (such as at the temperature of 150-300 ℃ and the pressure of 1-10 Mpa), has good bonding effect with metal devices or reinforcing sheets, and greatly improves the conductive stability.
Description
Technical Field
The invention belongs to the technical field of conductive adhesive, and particularly relates to conductive adhesive for a flexible printed circuit board and a preparation method thereof.
Background
With the rapid development of the electronic industry, electronic products further develop toward miniaturization, light weight and high-density assembly, and the development of flexible circuit boards is greatly promoted, and flexible printed circuits are used as a special component for connecting electronic components and realizing the integration of component devices and wire connection, and have the excellent performances of light weight, thinness, multiple structures, bending resistance and the like. Can be widely applied to the fields of mobile phones, liquid crystal displays and the like.
In order to shield electromagnetic noise generated by a flexible printed circuit board, an electromagnetic wave shielding film capable of shielding electromagnetic noise is generally attached to the flexible printed circuit board, and the electromagnetic wave shielding film is generally attached by a conductive adhesive so that bending resistance is not impaired. In practical application, the conductive adhesive is adhered between the terminal portion of the printed circuit board and the ground layer, thereby achieving electrical conduction.
The conductive adhesive is an adhesive with certain conductive performance after solidification, and generally consists of conductive filler, a resin matrix, an auxiliary agent and the like. The resin matrix mainly plays a role in adhesion, and mainly comprises epoxy resin, acrylic resin, carbamate resin, silicone rubber resin, bismaleimide resin, phenolic resin, melamine resin, polyimide resin and the like. The conductive filler is used to form a conductive path, and carbon powder, silver powder, copper powder, nickel powder, solder powder, aluminum powder, silver-plated copper powder, resin balls with plated surfaces, and the like can be used. However, in the traditional conductive adhesive, the conductive filler powder is only in physical contact, so that the problems of large contact thermal resistance and electric resistance exist, and the conductivity of the conductive adhesive is not high, so that the excellent high conductivity performance cannot be realized.
In order to solve the problem of poor conductive interconnection performance of the conductive adhesive, the main method at present is to greatly improve the conductive performance by adopting a method for increasing the filler content, but the high filler content brings higher cost; the resin matrix plays a role in bonding in the conductive paste, so increasing the filler content will reduce the resin content, which will affect the bonding strength of the conductive paste in flexible printed wiring board applications.
Patent CN 106883805A discloses a heat-conducting and electric-conducting adhesive, which comprises the following components in mass ratio: 5% -20% of epoxy resin; 75% -90% of low-melting-point alloy filler; 1% -10% of curing agent; 0.1% -3% of accelerator; the thinner is 0.1-10%, and can also comprise film forming agent and thixotropic agent. The low-melting-point alloy filler at least contains any one or a mixture of at least two of SnBi, snBiAg, snBiCu, snIn or SnInBi powder fillers. The heat-conducting and electric-conducting adhesive provided by the invention can realize good metallurgical interconnection after being cured at low temperature. Patent CN 111334221A discloses a conductive adhesive and application thereof, the conductive adhesive comprises: the adhesive layer, a plurality of conductive balls distributed in the adhesive layer and a plurality of low-melting-point alloy balls/powder distributed in the adhesive layer in a scattered manner. The alloy melting point of the low-melting-point alloy ball/powder is lower than 300 ℃, and the low-melting-point alloy ball/powder is not limited to one or a combination of a plurality of silver, nickel, tin and indium. The invention distributes a plurality of low-melting-point alloy balls/powder in the adhesive layer, when the electronic components are connected with each other, the low-melting-point alloy balls/powder are melted at high temperature, so that the electric connection of the electronic components is firmer and no deviation occurs. Meanwhile, a one-time mixing mode of the conductive ball, the low-melting-point alloy ball/powder and the colloid is adopted, so that the formula process is simplified, the flexibility of specification performance adjustment is improved, and the product characteristics are realized.
The prior art is that alloy particles are directly added into conductive adhesive, the mixing processability of the adopted low-melting-point alloy and a resin matrix is poor, and when the conductive adhesive is applied to a flexible printed circuit board, the alloy particles in the conductive adhesive are easy to oxidize and corrode, so that the resistance is increased, and the grounding effect of the printed circuit board is reduced.
Disclosure of Invention
In view of the above drawbacks and shortcomings of the prior art, a primary object of the present invention is to provide a conductive paste for a flexible printed wiring board.
Another object of the present invention is to provide a method for preparing the above conductive adhesive.
The invention aims at realizing the following technical scheme:
a conductive paste for a flexible printed wiring board includes a resin matrix and low-melting-point metal conductive particles dispersed therein; the low-melting-point metal conductive particles are at least one metal particle in Sb, zn, pb, cd, bi, sn, in, ga.
Further, the conductive adhesive also comprises at least one high-melting-point metal conductive particle selected from Al, mg, cu, ag, mn, ni, au, silver-plated copper powder, silver-plated aluminum powder, silver-plated magnesium powder and silver-plated nickel powder.
Further, the conductive particles in the conductive adhesive are combinations of metal particles capable of forming an alloy at a temperature of 150-300 ℃ and a pressure of 1-10 Mpa.
Further, the conductive particles may have a spherical, platelet-like, dendritic, bead-chain-like or fibrous shape, and the conductive particles have a particle diameter of 2 to 50 μm.
Further preferably, the conductive particles are a combination of spherical conductive particles of a low-melting metal and conductive particles of a dendritic or bead-chain high-melting metal. Under the conductive adhesive system of the invention, the combination of the spherical conductive particles with low-melting point metal and the dendritic or bead-chain-shaped high-melting point conductive particles has better conductivity and conductivity stability than the spherical conductive particles, the dendritic or bead-chain-shaped conductive particles and the combination of the individual high-melting point conductive particles.
Further, the conductive particles refer to conductive particles modified by conductive polymer surfaces, and are prepared by the following method:
(1) Preparation of conductive polymer solution: stirring and mixing the conductive polymer, the solvent, the polyurethane adhesive and the coupling agent uniformly to obtain a conductive polymer solution;
(2) Surface modification of conductive particles: and (3) uniformly stirring and mixing the conductive polymer solution obtained in the step (1) and the conductive particles, and spray-drying to obtain the conductive particles with the conductive polymer surface modified.
Further, the conductive polymer in the step (1) refers to a polythiophene conductive polymer, a polyaniline conductive polymer or a polypyrrole conductive polymer.
Further, the solvent in the step (1) is a mixed solvent of isopropanol and N, N-dimethylformamide.
Further, the coupling agent in the step (1) refers to an aluminate coupling agent.
Further, in the step (1), the weight ratio of the raw materials is that the conductive polymer: solvent: polyurethane adhesive: coupling agent=10:50 to 500:5 to 20:0.5 to 2.
Further, the mass ratio of the conductive polymer solution to the conductive particles in the step (2) is 0.05-0.2:1 based on the mass of the conductive polymer.
Further, the spray drying temperature in the step (2) is 80-130 ℃.
Further, the resin matrix is thermosetting phenolic resin, epoxy resin, urethane resin, melamine resin, alkyd resin or polyimide resin.
Further, the weight ratio of the conductive particles in the conductive adhesive is 50% -90%.
The preparation method of the conductive adhesive for the flexible printed circuit board comprises the following preparation steps:
and (3) uniformly mixing the resin matrix glue solution and the conductive particles through vacuum mixing to obtain the conductive glue for the flexible printed circuit board.
Compared with the prior art, the invention has the beneficial effects that:
(1) The conductive adhesive has good mixing processing performance with the resin matrix through the independently added low-melting-point metal conductive particles, can realize alloy in the bonding application process of the flexible printed circuit board (such as at the temperature of 150-300 ℃ and the pressure of 1-10 Mpa), has good bonding effect with metal devices or reinforcing sheets, and greatly improves the conductive stability.
(2) The invention can further improve conductivity and conductivity stability by combining the low-melting-point metal spherical conductive particles with the dendritic or bead-chain high-melting-point metal conductive particles.
(3) According to the invention, the conductive polymer is further adopted to carry out surface modification on the metal conductive particles, the polyurethane adhesive and the coupling agent solidify the conductive polymer on the surfaces of the metal conductive particles in the spray drying process, so that the dispersion performance of the metal conductive particles in the resin matrix can be remarkably enhanced, better conductive performance can be achieved under the condition of less conductive particle addition, the bonding strength is improved, and the oxidation corrosion resistance of the metal conductive particles can be remarkably enhanced.
Drawings
FIG. 1 is an electron micrograph of dendritic silver-coated copper powder used in an embodiment of the present invention;
FIG. 2 is an electron micrograph of a bead chain type conductive nickel powder used in an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples and drawings, but embodiments of the present invention are not limited thereto.
Example 1
The conductive adhesive for the flexible printed circuit board comprises an epoxy resin adhesive, sn metal particles and Cu metal particles, wherein the Sn metal particles and the Cu metal particles are spherical in shape and have particle diameters of about 10 microns. The epoxy resin adhesive comprises 15% by weight of Sn metal particles and 30% by weight of Cu metal particles.
The preparation method of the conductive adhesive comprises the following steps: and (3) mixing the epoxy resin adhesive, the Sn metal particles and the Cu metal particles uniformly by vacuum mixing to obtain the conductive adhesive for the flexible printed circuit board.
Example 2
The conductive paste for a flexible printed wiring board of the present embodiment includes an epoxy resin binder, sn metal particles, bi metal particles, and Ag metal particles, wherein the Sn metal particles, the Bi metal particles, and the Ag metal particles are spherical in shape, the average particle diameter of the Sn metal particles and the Bi metal particles is 20 μm, and the average particle diameter of the Ag metal particles is 10 μm. The epoxy resin adhesive comprises 15% by weight, 40% of Sn metal particles, 30% of Bi metal particles and 15% of Ag metal particles.
The preparation method of the conductive adhesive comprises the following steps: and uniformly mixing the epoxy resin adhesive with the Sn metal particles, the Bi metal particles and the Ag metal particles through vacuum mixing to obtain the conductive adhesive for the flexible printed circuit board.
Example 3
The conductive adhesive for the flexible printed circuit board comprises an epoxy resin adhesive, sn metal particles and silver-plated copper powder, wherein the Sn metal particles and the silver-plated copper powder are spherical in shape and have particle sizes of about 10 microns. The epoxy resin adhesive comprises 20% by weight, 40% by weight of Sn metal particles and 40% by weight of silver-plated copper powder.
The preparation method of the conductive adhesive comprises the following steps: and (3) uniformly mixing the epoxy resin adhesive, spherical Sn metal particles and silver-plated copper powder through vacuum mixing to obtain the conductive adhesive for the flexible printed circuit board.
Example 4
The conductive paste for flexible printed circuit board of this example comprises epoxy resin binder 20%, spherical Sn metal particles 40% and dendritic silver-plated copper powder 40% by weight, and the spherical Sn metal particles and dendritic silver-plated copper powder (commercially available, the electron micrograph of which is shown in fig. 1).
The preparation method of the conductive adhesive comprises the following steps: and (3) uniformly mixing the epoxy resin adhesive, spherical Sn metal particles and dendritic silver-plated copper powder through vacuum mixing to obtain the conductive adhesive for the flexible printed circuit board.
Comparative example 1
In this comparative example, the composition of the conductive paste was 20% of the epoxy resin binder and 80% of the spherical Sn metal particles, as compared with example 4.
Comparative example 2
In this comparative example, the composition of the conductive paste was 20% epoxy binder and 80% dendritic silver-plated copper powder, as compared with example 4.
Comparative example 3
In this comparative example, the composition of the conductive paste was 20% of the epoxy binder, 40% of the spherical silver-plated copper powder, and 40% of the dendritic silver-plated copper powder, as compared with example 4.
Example 5
This example is the same as example 4 except that bead-chain conductive nickel powder (commercially available, whose electron micrograph is shown in fig. 2) is used instead of dendritic silver-plated copper powder.
Comparative example 4
This comparative example compared to example 5, the conductive paste consisted of 20% epoxy binder and 80% bead-chain conductive nickel powder.
Comparative example 5
In this comparative example, the composition of the conductive paste was 20% of the epoxy resin binder, 40% of the spherical nickel powder and 40% of the bead-chain-like conductive nickel powder, as compared with example 5.
The conductive adhesives obtained in the above examples and comparative examples were bonded to a metal copper sheet at 160℃and 3MPa, and then subjected to initial resistivity measurement and conductive stability test (resistivity measurement after 100 repeated bending at 90 ℃) and the test results are shown in Table 1 below.
TABLE 1
| Initial resistivity (Ω. M) | Resistivity after 100 times bending (Ω. M) | |
| Example 1 | 2.73×10 -6 | 7.58×10 -6 |
| Example 2 | 1.95×10 -6 | 5.06×10 -6 |
| Example 3 | 2.21×10 -6 | 5.59×10 -6 |
| Example 4 | 1.52×10 -6 | 1.80×10 -6 |
| Comparative example 1 | 4.57×10 -6 | 1.24×10 -5 |
| Comparative example 2 | 2.38×10 -6 | 4.87×10 -6 |
| Comparative example 3 | 3.19×10 -6 | 5.20×10 -6 |
| Example 5 | 1.68×10 -6 | 1.83×10 -6 |
| Comparative example 4 | 2.57×10 -6 | 4.82×10 -6 |
| Comparative example 5 | 3.52×10 -6 | 5.11×10 -6 |
As can be seen from the results of table 1, the combination of spherical conductive particles using a low-melting metal with dendritic or bead-chain-like high-melting conductive particles has better conductivity and conductivity stability than spherical conductive particles, dendritic or bead-chain-like conductive particles alone, and high-melting conductive particles alone. The reason for this may be that the low-melting metal spherical conductive particles further form a more uniform branched stable structure with the dendritic or bead-chain-like high-melting conductive particles during the high-temperature lamination.
Example 6
The conductive adhesive for the flexible printed circuit board comprises 20% of epoxy resin adhesive, 55% of conductive polymer surface modified Sn metal particles and 25% of conductive polymer surface modified Cu metal particles in percentage by weight.
The preparation method of the conductive adhesive comprises the following steps: and uniformly mixing the epoxy resin adhesive and Sn and Cu metal particles modified on the surface of the conductive polymer through vacuum mixing to obtain the conductive adhesive for the flexible printed circuit board.
The Sn metal particles and Cu metal particles with the surface modified by the conductive polymer are prepared by the following method:
(1) Preparation of conductive polymer solution: according to the weight parts, 10 parts of polythiophene conductive polymer is added into 200 parts of mixed solvent of isopropanol and N, N-dimethylformamide in a volume ratio of 1:2, and uniformly stirred and mixed, and then 10 parts of polyurethane adhesive and 1 part of aluminate coupling agent are added, and uniformly stirred and mixed, so that a conductive polymer solution is obtained.
(2) Surface modification of conductive particles: and (3) uniformly stirring and mixing the conductive polymer solution obtained in the step (1) with 55 parts of Sn metal particles and 25 parts of Cu metal particles, wherein the Sn metal particles and the Cu metal particles are spherical in shape and have particle diameters of about 10 mu m. And (5) spray drying to obtain the conductive particles with the surface modified by the conductive polymer.
Example 7
The conductive adhesive for the flexible printed circuit board comprises 20% of epoxy resin adhesive, 40% of conductive polymer surface modified Sn metal particles, 30% of conductive polymer surface modified Bi metal particles and 10% of conductive polymer surface modified Ag metal particles in percentage by weight.
The preparation method of the conductive adhesive comprises the following steps: and uniformly mixing the epoxy resin adhesive and Sn, bi and Ag metal particles modified on the surface of the conductive polymer through vacuum mixing, so as to obtain the conductive adhesive for the flexible printed circuit board.
The Sn, bi and Ag metal particles with the surface modified by the conductive polymer are prepared by the following method:
(1) Preparation of conductive polymer solution: according to the weight parts, 10 parts of polythiophene conductive polymer is added into 300 parts of mixed solvent of isopropanol and N, N-dimethylformamide in a volume ratio of 1:2, and uniformly stirred and mixed, and then 10 parts of polyurethane adhesive and 1 part of aluminate coupling agent are added, and uniformly stirred and mixed, so that a conductive polymer solution is obtained.
(2) Surface modification of conductive particles: the conductive polymer solution in the step (1) is uniformly mixed with 40 parts of Sn metal particles, 30 parts of Bi metal particles and 10 parts of Ag metal particles by stirring, wherein the shapes of the Sn metal particles, the Bi metal particles and the Ag metal particles are spherical, the average particle size of the Sn metal particles and the Bi metal particles is 20 mu m, and the average particle size of the Ag metal particles is 10 mu m. And (5) spray drying to obtain the conductive particles with the surface modified by the conductive polymer.
The conductive pastes obtained in examples 1 to 2 and examples 6 to 7 above were bonded to a metal copper sheet at 160℃and 3MPa, and then subjected to initial resistivity measurement and wet thermal oxidation (humidity: 90%, temperature: 120℃and air conditioning: 120 hours), and the results of the measurements are shown in Table 2 below.
TABLE 2
| Initial resistivity (Ω. M) | Resistivity after wet heat oxidation (Ω. M) | |
| Example 1 | 2.73×10 -6 | 9.36×10 -6 |
| Example 2 | 1.95×10 -6 | 7.28×10 -6 |
| Example 6 | 2.58×10 -6 | 3.18×10 -6 |
| Example 7 | 1.87×10 -6 | 2.85×10 -6 |
As can be seen from the results in table 2, the invention can achieve better conductivity under the condition of less conductive particle addition amount by further adopting the conductive polymer to carry out surface modification on the metal conductive particles, improves the bonding strength, and can obviously enhance the oxidation corrosion resistance of the metal conductive particles.
The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.
Claims (6)
1. A conductive paste for a flexible printed wiring board, comprising a resin matrix and conductive particles dispersed therein, the conductive particles comprising low-melting metal conductive particles and high-melting metal conductive particles; the low-melting-point metal conductive particles are at least one metal particle in Sb, zn, pb, cd, bi, sn, in, ga; the high-melting-point metal conductive particles are at least one metal particle selected from Al, mg, cu, ag, mn, ni, au, silver-plated copper powder, silver-plated aluminum powder, silver-plated magnesium powder and silver-plated nickel powder;
the low-melting-point metal conductive particles are spherical, the high-melting-point metal conductive particles are dendritic or bead-chain, and the particle sizes of the low-melting-point metal conductive particles and the high-melting-point metal conductive particles are 2-50 mu m;
the conductive particles are conductive particles modified by the surface of a conductive polymer, and are prepared by the following method:
(1) Preparation of conductive polymer solution: stirring and mixing the conductive polymer, the solvent, the polyurethane adhesive and the coupling agent uniformly to obtain a conductive polymer solution;
(2) Surface modification of conductive particles: and (3) uniformly stirring and mixing the conductive polymer solution obtained in the step (1) and the conductive particles, and spray-drying to obtain the conductive particles with the conductive polymer surface modified.
2. The conductive paste for flexible printed wiring board according to claim 1, wherein the conductive particles in the conductive paste are a combination of metal particles capable of forming an alloy at a temperature of 150 to 300 ℃ and a pressure of 1 to 10 mpa.
3. The conductive paste for flexible printed wiring board according to claim 1, wherein the conductive polymer in step (1) is a polythiophene conductive polymer, a polyaniline conductive polymer or a polypyrrole conductive polymer; the solvent is a mixed solvent of isopropanol and N, N-dimethylformamide; the coupling agent is an aluminate coupling agent; the weight ratio of the raw materials is that the conductive polymer: solvent: polyurethane adhesive: coupling agent=10:50 to 500:5 to 20:0.5 to 2.
4. The conductive paste for flexible printed circuit board according to claim 1, wherein the mass ratio of the conductive polymer solution to the conductive particles in the step (2) is 0.05-0.2:1 based on the mass of the conductive polymer; the spray drying temperature is 80-130 ℃.
5. A conductive adhesive for a flexible printed wiring board according to claim 1 or 2, wherein the resin base is a thermosetting phenolic resin, epoxy resin, urethane resin, melamine resin, alkyd resin or polyimide resin; the weight ratio of the conductive particles in the conductive adhesive is 50% -90%.
6. The method for preparing the conductive adhesive for the flexible printed circuit board according to any one of claims 1 to 5, which is characterized by comprising the following preparation steps:
and (3) uniformly mixing the resin matrix glue solution and the conductive particles through vacuum mixing to obtain the conductive glue for the flexible printed circuit board.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210964368.4A CN115197658B (en) | 2022-08-11 | 2022-08-11 | Conductive adhesive for flexible printed circuit board and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210964368.4A CN115197658B (en) | 2022-08-11 | 2022-08-11 | Conductive adhesive for flexible printed circuit board and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115197658A CN115197658A (en) | 2022-10-18 |
| CN115197658B true CN115197658B (en) | 2024-03-19 |
Family
ID=83585499
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210964368.4A Active CN115197658B (en) | 2022-08-11 | 2022-08-11 | Conductive adhesive for flexible printed circuit board and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115197658B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101928540A (en) * | 2009-10-16 | 2010-12-29 | 北京工业大学 | Epoxy conductive adhesive and preparation method thereof |
| CN104718579A (en) * | 2012-07-24 | 2015-06-17 | 株式会社大赛璐 | Conductive fiber-coated particle, curable composition and cured article derived from curable composition |
| CN111040691A (en) * | 2019-11-29 | 2020-04-21 | 扬州富威尔复合材料有限公司 | Multi-component metal conductive adhesive based on different melting points and preparation method thereof |
-
2022
- 2022-08-11 CN CN202210964368.4A patent/CN115197658B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101928540A (en) * | 2009-10-16 | 2010-12-29 | 北京工业大学 | Epoxy conductive adhesive and preparation method thereof |
| CN104718579A (en) * | 2012-07-24 | 2015-06-17 | 株式会社大赛璐 | Conductive fiber-coated particle, curable composition and cured article derived from curable composition |
| CN111040691A (en) * | 2019-11-29 | 2020-04-21 | 扬州富威尔复合材料有限公司 | Multi-component metal conductive adhesive based on different melting points and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115197658A (en) | 2022-10-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6238599B1 (en) | High conductivity, high strength, lead-free, low cost, electrically conducting materials and applications | |
| JP3454509B2 (en) | How to use conductive materials | |
| KR100832628B1 (en) | Conductive paste | |
| US8920580B2 (en) | Solder paste and electronic device | |
| JP4593123B2 (en) | Conductive adhesive | |
| WO2014046093A1 (en) | Anisotropic conductive adhesive | |
| US20020005247A1 (en) | Electrically conductive paste materials and applications | |
| WO2011111324A1 (en) | Electromagnetic-shielding film, flexible substrate formed using same, and process for producing same | |
| JP4998732B2 (en) | Anisotropic conductive adhesive | |
| JPWO2006080247A1 (en) | Conductive paste | |
| JP2013152867A (en) | Conductive particle, anisotropic conductive material, and connection structure | |
| WO2013125388A1 (en) | Anisotropic conductive connection material, connection structure, manufacturing method and connection method for connection structure | |
| CN114276766A (en) | Nano-silver sintered conductive adhesive for microelectronic packaging and preparation method thereof | |
| JP2013054851A (en) | Conductive particle, method of manufacturing conductive particle, anisotropic conductive material and connection structure | |
| CN115197658B (en) | Conductive adhesive for flexible printed circuit board and preparation method thereof | |
| JP4770139B2 (en) | Conductive particles and anisotropic conductive material composition | |
| JP6196131B2 (en) | Metal foil for press bonding and electronic component package | |
| JP4867805B2 (en) | Adhesive for electrode connection | |
| JP3513636B2 (en) | Composite conductive powder, conductive paste, electric circuit and method for producing electric circuit | |
| WO2015141342A1 (en) | Anisotropic conductive adhesive agent | |
| JP2680412B2 (en) | Anisotropic conductive film | |
| JP5273514B2 (en) | Electrode connecting adhesive and method for producing the same | |
| KR20090059298A (en) | Conductive paste having a good flexibility and heat resistance | |
| JPH07252460A (en) | Adhesive | |
| CN113409993B (en) | High-stability conductive adhesive film and printed circuit board |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |