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A kind of preparation method of prepolymer containing nano-silver flakes and its conductive adhesive

A technology of nano-silver flakes and prepolymers, applied in the field of conductive adhesives, can solve problems such as high price, unfavorable low cost, and system incompatibility, and achieve the effects of optimizing conductivity, improving conductivity, and wide application range

Active Publication Date: 2021-12-07
佛山市瑞联福电子科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the high surface activity of nano-silver, the solution of directly adding nano-silver powder to the conductive adhesive is prone to system incompatibility, that is, agglomeration occurs after adding nano-silver. There is uneven dispersion of the conductive adhesive system, which makes the product unusable
[0005] And if the added nano-silver silver powder is nano-silver particles that can be cold-welded at low temperature, because the nano-silver particles improve the conductivity by eliminating the grain boundaries between the micron-sized conductive fillers after sintering, this limits the amount of conductive fillers that must be must be silver powder
In this case, it not only limits the flexibility of the conductive adhesive to the conductive filler, but also must choose relatively high-priced silver powder, which is not conducive to low-cost products.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0031] A preparation method of a prepolymer containing nano-silver flakes, comprising the following steps:

[0032] (1) Prepare an aqueous solution of polyhydric alcohol with a concentration of 50-100 wt%, and preheat to 60-90°C;

[0033] (2) Add polyvinylpyrrolidone in the aqueous solution of above-mentioned polyhydric alcohol, until dissolving completely;

[0034] (3) Dissolve silver nitrate in water until the dissolution is complete, then heat to 60-90°C;

[0035] (4) Add the silver nitrate solution into the above polyol aqueous solution, heat to 100-120°C, vacuumize, evaporate the water completely, and continue the reaction for 1-12h;

[0036] In this scheme, the silver nitrate solution does not use an external reducing agent, but is oxidized by the polyhydric alcohol in the system. The polyhydric alcohol is excessive relative to the silver nitrate, and the alcohol groups of some polyhydric alcohols are oxidized into aldehyde groups, and the aldehyde groups carry Reducti...

Embodiment A3

[0084] A preparation method of a prepolymer containing nano-silver flakes, comprising the following steps:

[0085] (1) Prepare an aqueous solution of polyhydric alcohol with a concentration of 60 wt%, and preheat it to 80°C; the polyhydric alcohol is polyethylene glycol and polypropylene glycol, and the molecular weight is controlled at 1000-2000g / mol;

[0086] (2) Add 10 g / L of polyvinylpyrrolidone to the aqueous solution of the above-mentioned polyol until it dissolves completely;

[0087] (3) Dissolve silver nitrate in water until the dissolution is complete to prepare 50g / L silver nitrate, then heat to 60°C;

[0088] (4) Add the silver nitrate solution into the above polyol aqueous solution, heat to 110° C., vacuumize, evaporate the water completely, and continue the reaction for 10 h;

[0089] (5) drop the temperature to 100°C, add diisocyanate dropwise, the amount of addition is controlled at 1.2:1 according to the molar ratio x of -OH and -NCO; thereby obtain the poly...

Embodiment B

[0097] A preparation method of a prepolymer containing nano-silver flakes, comprising the following steps:

[0098] (1) Prepare an aqueous solution of polyhydric alcohol with a concentration of 50 wt%, and preheat it to 60°C; the polyhydric alcohol is ethylene glycol, polyethylene glycol and polypropylene glycol, and the molecular mass is controlled at 1000-2000g / mol;

[0099] (2) Add 10 g / L of polyvinylpyrrolidone to the aqueous solution of the above-mentioned polyol until it dissolves completely;

[0100] (3) Dissolve silver nitrate in water until the dissolution is complete to prepare 30g / L silver nitrate, then heat to 90°C;

[0101] (4) Add the silver nitrate solution into the above polyol aqueous solution, heat to 120° C., vacuumize, completely evaporate the water, and continue the reaction for 12 hours;

[0102] (5) cooling down to 60°C, adding diisocyanate dropwise, the amount of addition is controlled at 1:1.2 according to the molar ratio x of -OH and -NCO; thereby ob...

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Abstract

A preparation method of a prepolymer containing nano silver flakes and conductive adhesive thereof, the preparation method of its prepolymer prepares the prepolymer containing nano silver flakes through steps (1)-step (5); and in step (4 ) before adding silver ions, the present invention adds polyvinylpyrrolidone earlier in step (2); by introducing polyvinylpyrrolidone, can generate the nano-silver flake of two-dimensional structure; Its conductive adhesive comprises conductive filler, diluent, containing nano-silver sheet Prepolymers, Initiators and Auxiliaries. The invention adopts in-situ generation of polyurethane prepolymer containing nano-silver flakes, which solves the problem of dispersion of nano-powders in resin; at the same time, the introduction of nano-silver flakes can form an effective bridging effect between micron conductive powders and improve electrical conductivity.

Description

technical field [0001] The invention relates to the technical field of conductive adhesives, in particular to a preparation method of a prepolymer containing nano-silver flakes. Background technique [0002] Conventional conductive adhesives are composed of conductive fillers, resins, diluents, initiators, and various additives. Conductive adhesives are generally used in bonding scenarios, that is, sandwiched between two interfaces to be bonded. Therefore, it is usually required that the conductive adhesive does not contain solvents, or contains a small amount of volatile solvents. Containing solvents may cause bubbles during the heating and curing process of the conductive adhesive, resulting in bonding defects. Thus, the viscosity adjustment and control of conductive adhesives strongly depend on the use of diluents. Thinner is a reactive low-molecular compound that can react with the resin and fix it, so that it will not cause a large number of bubbles during heat curin...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09J175/08C09J133/04C09J175/04C09J9/02C08G18/32C08G18/48C08G18/66
CPCC08G18/3206C08G18/4808C08G18/4833C08G18/6674C08K2003/0806C08K2201/011C09J9/02C09J133/04C09J175/04C09J175/08C08L33/04C08K7/00C08K3/08C08L75/08
Inventor 胡永能周虎高峰陈法波黄良辉
Owner 佛山市瑞联福电子科技有限公司