A kind of method for preparing high-performance conducting resin
Technical field
The invention belongs to technical field of material, particularly a kind of method for preparing the high-performance isotropic conductive adhesive.
Background technology
The Sn/Pb scolder has been continued to use for many years as the employed a kind of basic connection material of Electronic Packaging industry, as connecting at chip; IC (integrate circuit) is assembled into PCB aspects such as (print circuit board) application is all arranged.But belong to heavy metal element and have very big toxicity because the Sn/Pb scolder exists Pb, the welding temperature of scolder is too high, damages device and substrate easily; Have " bridge formation " phenomenon in the scolder, can not be used for aspects such as high density integrated circuit drawbacks limit its application.Owing to use in the conductive resin is the metal-powder conduction, the linear resolution of connection is improved a lot, can satisfy the requirement of heavy body, and matrix is a macromolecular material, can be used on the flexible base, board, more can adapt to miniaturization of electronic products, the requirement of lightness, advantage such as simultaneously the simple solidification value of coating process of conductive resin is low, make conductive resin as the substitute of Sn/Pb widely at SMT, SMD is applied among the PCB.
Substitute as the Sn/Pb scolder, conductive resin is in some shortcomings that also shown self in the application of reality: the jumping phenomenon that resistance is just arranged in the time of will reaching 33% (volume percent) left and right sides as the content of the conductive filler material in the conductive resin, cause that the content of resin reduces relatively in the conductive resin, and resin is the main source of cohesive strength, so the resistance to impact shock of conductive resin is good inadequately than the Sn/Pb scolder; Conductive resin is to form conductive network by the conducting particles of filling in resin matrix to conduct electricity, the quality that network forms all has very big influence to the electric property and the ageing-resistant performance of conductive resin, the quality of network depends primarily on kind, pattern, size, electroconductibility of filled conductive particle etc., the conductive resin that adopts different fillers to fill that a lot of bibliographical informations arranged both at home and abroad recently is as the silver-colored powder mix of the silver powder of filling micron dimension, micron and nanometer scale, flake silver powder, nickel powder etc.Fill the conductive resin of granular conductive filler material because the contact area between particle and the particle is little, contact is unstable, and conductive resin shows very strong contact resistance unstable.
For this reason, develop a kind of electric conductivity height, resistance stabilization, isotropic conductive adhesive that physical strength is good is badly in need of very much.Monodimension nanometer material is owing to electric property, mechanical property and good chemical stability with special structure and uniqueness are widely studied and applied.Wherein nano silver wire is owing to radius-of-curvature little suitable " point discharge ", and it is less to have good field emissivity and threshold field, and emission and emission bit density are higher.The one dimension nano silver wire both can have been given full play to the advantage of the fibrous texture of nano wire as the conductive filler material of conductive resin, in the resin matrix of conductive resin, form conductive network better, can bring into play a tunnel conduction effect and an emission conductive effect of nanoparticle again.Adopt nano silver wire and small amount of silver nanoparticle to mix herein and prepared a kind of high-performance conducting resin as the conductive filler material of conductive resin as conductive filler material.This conductive resin that makes has good electric property, and (volume specific resistance reaches 1.0 * 10
-4And very high shear strength (shear strength when being substrate with Al is 17MPa) Ω cm).
Summary of the invention
The object of the present invention is to provide easy, a kind of method for preparing high-performance conducting resin cheaply.
The step of the technical solution used in the present invention is as follows:
One, material mixture ratio
Concentration is 99.9% anhydrous nitric acid silver AgNO
3,
Concentration is 99.8% no water glycol C
2H
6O
2
Concentration is 98% polyvinylpyrrolidone PVP
Chemical pure Resins, epoxy
Chemical pure resol
The chemical pure polyurethane curing agent
Purity is 80% oxidation inhibitor PL-10 phosphorous acid ester three (2,4-two special basic phenyl) ester
Purity is 90% linking agent DMAM N-N`-methylene-bisacrylamide
Purity is 88% anti-aging agent RD (C
12H
15N)
n
Above reagent does not all pass through purification process;
Two, preparation process:
1) AgNO
3Being dissolved in ethylene glycol formation concentration is clear solution, and PVP is dissolved in ethylene glycol and forms clear solution.The concentration ratio of two kinds of ethylene glycol solutions is 1: 5~6;
2) with the AgNO of 1 volume
3Ethylene glycol solution and the ethylene glycol solution of the PVP of the 1 volume ethylene glycol solution that injects 1.5~3 volumes simultaneously mix, then with this solution in the 60~90min that under 150~170 ℃ of temperature, refluxes under the magnetic agitation.Backflow finishes the back and add washing with acetone, centrifugation 20~30min under 8000~10000 rev/mins of speed then in solution.Remove upper solution, recentrifuge 10min after lower floor's solids washed with acetone obtains pressed powder dry 24~48h in vacuum drying oven.
3) the concrete prescription of novel high-performance conductive resin is: Resins, epoxy (or resol), solidifying agent, oxidation inhibitor, the weight percent of anti-aging agent linking agent and nano silver wire and nanoparticle mixed powder is 1: 0.5~0.7: 0.1~0.12: 0.05~0.08: 0.1~0.11: 0.5~0.7, concrete process for preparation is to mix in the mixed powder adding Resins, epoxy of nano silver wire and Nano silver grain or the resol, in colloid mixture, add polyurethane curing agent then, linking agent, oxidation inhibitor, anti-aging agent mixes, after stirring, colloid is put into ultrasonic wave carry out supersound process 10~20min.
The beneficial effect that the present invention has is: adopt the nano silver wire and the nanoparticle mixture of chemical reduction method preparation to prepare a kind of high-performance isotropic conductive adhesive as conductive filler material filling epoxy resin or resol.It is low that this conductive resin has resistivity than conventional conductive glue, advantage such as mechanical property, ageing-resistant performance are good.The method cost of novel ground of this preparation high-performance conducting resin is low, and method is simple, and controllability is good, has very high practical value for the development of Electronic Packaging industry.
Description of drawings
Accompanying drawing is by the nano silver wire of embodiment 1 preparation and the scanning electron microscope (SEM) and transmission electron microscope (TEM) photo of Nano silver grain mixed powder.
Embodiment
Embodiment 1
Carry out according to preparation process (1) and (2), adopt the 0.1mol/l AgNO of 1 volume
3Ethylene glycol solution, 1 volume 0.6mol/lPVP ethylene glycol solution injects 2 volume ethylene glycol solutions, and mixed solution is at 160 ℃ of following backflow 60min.Reaction finishes the back and add 5~10 times of volume acetone centrifugal 30min in the whizzer of 10000rpm then in mixing solutions, removes upper solution, 3 final vacuum dryings of lower floor's solids washed with acetone.The test of transmission electron microscope observation (TEM) is that dried powder supersound process is dispersed in the toluene, then with drips of solution on the copper mesh that is coated with carbon film, drying at room temperature, TEM model are JEOL200CX.The sample of field emission scanning electron microscope (FESEM) is powdered sample to be dispersed in drop in the ethanol on the sample table, treat ethanol volatilization after, scanning electron microscopic observation, the scanning electron microscope model is FEI SIRION.What Fig. 1 (a) showed is the prepared nano silver wire and the SEM photo of Nano silver grain mixed powder, can see among the figure on the surface of nanoparticle attached to nano wire.What Fig. 1 (b) showed is the TEM photo of preparation nano silver wire and nanoparticle mixed powder.
Carry out according to preparation process (3), the weight percent of concrete Resins, epoxy, solidifying agent, oxidation inhibitor, anti-aging agent linking agent and nano silver wire and nanoparticle mixed powder is 1: 0.6: 0.11: 0.06: 0.11: 0.6, the mixed powder of nano silver wire and Nano silver grain added in Resins, epoxy or the resol mix, adding an amount of polyurethane curing agent, linking agent, oxidation inhibitor, anti-aging agent then in colloid mixture mixes, after stirring, colloid is put into ultrasonic wave carry out the about 15min of supersound process.The glue for preparing is evenly coated with between two blocks of sheet glass on the poly (methyl methacrylate) plate of dehydrated alcohol wiping, under the infrared lamp irradiation, is cured, set time 5h, 70 ℃ of solidification values, solidifying pressure 0.55MPa.Volume specific resistance is according to ρ=Rbc/a, and R is actual measurement resistance, and a is a glue-line length, and b is the glue-line width, and c is a bondline thickness, adopts four electrode resistance methods of testing, and the test of resistance is to carry out on the ZL-5 intelligent LCR measuring.What table 1 provided is the volume specific resistance and traditional comparison of using conductive resin of the high-performance conducting resin of preparation. the cohesive strength sample prepares according to JISK 6850 (Japanese Industrial Standards), with the aluminium flake is substrate, sample adopts the test piece of single face overlap joint, L=12.5mm ± 0.5mm, B=25mm ± 0.5mm, the speed of applied load is defined in below the 4.9kN/min cohesive strength τ
BTo destroy load P
BCalculate.τ
B=P
B/LB。The test of cohesive strength is carried out on microcomputer control electronics universal testing machine (Rui Geer of Shenzhen Instr Ltd., specification 10kN, 0.5 grade of accuracy rating), and table 2 has provided the comparison of shear strength with the tradition use conductive resin of high-performance conducting resin.Ageing-resistant performance test is that the conductive resin specimen is put into temperature is 85 ℃ of climatic chambers that humidity is 85%RH, the variation of test performance behind the 500h, and ageing-resistant performance and the tradition that table 3 has provided the high-performance conducting resin of preparation used the comparison of conductive resin.
Embodiment 2
Carry out according to preparation process (1) and (2), adopt the 0.1mol/l AgNO of 1 volume
3Ethylene glycol solution, 1 volume 0.5mol/lPVP ethylene glycol solution injects 1.5 volume ethylene glycol solutions, and mixed solution is at 150 ℃ of following backflow 70min.Reaction finishes the back and add 5~10 times of volume acetone centrifugal 20min in the whizzer of 8000rpm then in mixing solutions, removes upper solution, 3 final vacuum dryings of lower floor's solids washed with acetone.Carry out according to preparation process (3), the weight percent of concrete resol, solidifying agent, oxidation inhibitor, anti-aging agent linking agent and nano silver wire and nanoparticle mixed powder is 1: 0.5: 0.1: 0.05: 0.1: 0.5, the mixed powder of nano silver wire and Nano silver grain added in Resins, epoxy or the resol mix, adding an amount of polyurethane curing agent, linking agent, oxidation inhibitor, anti-aging agent then in colloid mixture mixes, after stirring, colloid is put into ultrasonic wave carry out the about 10min of supersound process.The glue for preparing is evenly coated with between two blocks of sheet glass on the poly (methyl methacrylate) plate of dehydrated alcohol wiping, under the infrared lamp irradiation, is cured, set time 6h, 75 ℃ of solidification values, solidifying pressure 0.8MPa.Volume specific resistance is according to ρ=Rbc/a, and R is actual measurement resistance, and a is a glue-line length, and b is the glue-line width, and c is a bondline thickness, adopts four electrode resistance methods of testing, and the test of resistance is to carry out on the ZL-5 intelligent LCR measuring.The cohesive strength sample is substrate according to JISK 6850 (Japanese Industrial Standards) preparation with the aluminium flake, and sample adopts the test piece of single face overlap joint, L=12.5mm ± 0.5mm, and B=25mm ± 0.5mm, the speed of applied load is defined in below the 4.9kN/min cohesive strength τ
BTo destroy load P
BCalculate.τ
B=P
B/LB。The test of cohesive strength is carried out on microcomputer control electronics universal testing machine (Rui Geer of Shenzhen Instr Ltd., specification 10kN, 0.5 grade of accuracy rating).Ageing-resistant performance test is that the conductive resin specimen is put into temperature is 85 ℃ of climatic chambers that humidity is 85%RH, the variation of test performance behind the 500h.The volume specific resistance that obtains conductive resin is 5.6 * 10
-3Ω cm, shear strength are that the volume specific resistance after 18.8MPa. wears out through 500h is 8.7 * 10
-3Ω cm, shear strength are 16.6MPa.
Embodiment 3
Carry out according to preparation process (1) and (2), adopt the 0.1mol/l AgNO of 1 volume
3Ethylene glycol solution, 1 volume 0.5mol/lPVP ethylene glycol solution injects 1.7 volume ethylene glycol solutions, and mixed solution is at 170 ℃ of following backflow 90min.Reaction finishes the back and add 5~10 times of volume acetone centrifugal 30min in the whizzer of 9000rpm then in mixing solutions, removes upper solution, 3 final vacuum dryings of lower floor's solids washed with acetone.Carry out according to preparation process (3), the weight percent of concrete Resins, epoxy (or resol), solidifying agent, oxidation inhibitor, anti-aging agent linking agent and nano silver wire and nanoparticle mixed powder is 1: 0.7: 0.12: 0.08: 0.11: 0.7, the mixed powder of nano silver wire and Nano silver grain added in Resins, epoxy or the resol mix, adding an amount of polyurethane curing agent, linking agent, oxidation inhibitor, anti-aging agent then in colloid mixture mixes, after stirring, colloid is put into ultrasonic wave carry out the about 10min of supersound process.The glue for preparing is evenly coated with between two blocks of sheet glass on the poly (methyl methacrylate) plate of dehydrated alcohol wiping, under the infrared lamp irradiation, is cured, set time 5.5h, 80 ℃ of solidification values, solidifying pressure 1.0MPa.Volume specific resistance is according to ρ=Rbc/a, and R is actual measurement resistance, and a is a glue-line length, and b is the glue-line width, and c is a bondline thickness, adopts four electrode resistance methods of testing, and the test of resistance is to carry out on the ZL-5 intelligent LCR measuring.The cohesive strength sample is substrate according to JISK 6850 (Japanese Industrial Standards) preparation with the aluminium flake, and sample adopts the test piece of single face overlap joint, L=12.5mm ± 0.5mm, and B=25mm ± 0.5mm, the speed of applied load is defined in below the 4.9kN/min cohesive strength τ
BTo destroy load P
BCalculate.τ
B=P
B/LB。The test of cohesive strength is carried out on microcomputer control electronics universal testing machine (Rui Geer of Shenzhen Instr Ltd., specification 10kN, 0.5 grade of accuracy rating).Ageing-resistant performance test is that the conductive resin specimen is put into temperature is 85 ℃ of climatic chambers that humidity is 85%RH, the variation of test performance behind the 500h.The volume specific resistance that obtains conductive resin is 1.0 * 10
-4Ω cm, shear strength are that the volume specific resistance after 17.2MPa. wears out through 500h is 1.2 * 10
-4Ω cm, shear strength are 16.9MPa.
The volume specific resistance of the high-performance conducting resin of table 1 preparation and traditional comparison of using conductive resin
Material | Volume specific resistance/Ω cm | Filler weight per-cent/% |
The common conducting resinl conditional electronic encapsulation Sn40/Pb60 scolder that the common conducting resinl domestic manufacturer that the common conducting resinl domestic manufacturer of the external manufacturer production of common conducting resinl of the external manufacturer production of novel high-performance conducting resinl produces produces | 1.2×10
-4 3.65×10
-1 7.5×10
-4 3.64 4.23×10
-3 3×10
-5 | 56 56 75 56 75 >95wt% |
The shear strength of the high-performance conducting resin of table 2 preparation and traditional comparison of using conductive resin
Material | Shearing resistance/MPa | Filler weight per-cent/% |
The common conducting resinl conditional electronic encapsulation Sn40/Pb60 scolder that the common conducting resinl domestic manufacturer that the common conducting resinl domestic manufacturer of the external manufacturer production of common conducting resinl of the external manufacturer production of epoxy resin novel high-performance conducting resinl produces produces | 30 17.6 17.1 15.3 14.3 11.7 40 | 0 56 56 75 56 75 >95 |
The ageing-resistant performance of the high-performance conducting resin of table 3 preparation and traditional comparison of using conductive resin
| Novel high-performance conductive resin (56wt%) | The common conductive resin (75wt%) of certain external manufacturer production | The common conductive resin (75wt%) that certain domestic manufacturer produces |
Before the burn-in test | Volume specific resistance/Ω cm shear strength/MPa | 1.2×10
-4 17.6
| 7.5×10
-4 15.3
| 4.23×10
-3 11.7
|
After 500h is aging | Volume specific resistance/Ω cm shear strength/MPa | 1.5×10
-4 15.0
| 1.1×10
-3 7.5
| 8.88×10
-3 6.4
|
Velocity of variation | Volume specific resistance/Ω cm shear strength/MPa | 25% 15% | 47% 51% | 110% 45% |