# US 12,224,081 B2 · Conductive paste and electronic device

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- Number: US 12,224,081 B2
- Document ID: US12224081B2
- Status: Granted
- Kind: B2
- Application number: 17/790,468
- Filed: 2021-11-23
- Published: 2023-06-01
- Granted: 2025-02-11
- Earliest claimed: 2021-03-04
- Assignees: Beijing Dream Ink Technologies Co., Ltd.
- Applicants: Beijing Dream Ink Technologies Co., Ltd.
- Inventors: Zhongwei Ren; Jiameng Kang
- Web page: https://patentgrep.com/patent/US12224081B2

## CPC

- H01B 1/22: the conductive material comprising metals or alloys
- C08G 18/10: Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
- C08G 18/4833: {Polyethers containing oxyethylene units}
- C08G 18/73: acyclic
- C08G 18/80: Masked polyisocyanates
- C08K 3/08: Metals
- C08L 63/00: Compositions of epoxy resins; Compositions of derivatives of epoxy resins
- C08L 75/08: from polyethers
- C09J 163/00: Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
- H05K 1/092: {Dispersed materials, e.g. conductive pastes or inks}
- H05K 1/095: {for polymer thick films, i.e. having a permanent organic polymeric binder}
- H05K 3/1283: {After-treatment of the printed patterns, e.g. sintering or curing methods}
- H05K 3/34: by soldering
- C08K 2003/0806: {Silver}
- C08K 2201/001: Conductive additives
- H05K 3/1216: {by screen printing or stencil printing}
- H05K 3/341: Surface mounted components
- H05K 2201/032: Materials
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

The present application provides a conductive paste and an electronic device, and relates to the technical field of function materials. The conductive paste according to the present application includes: a base resin, a solvent, a conductive filler, a curing agent, and an auxiliary agent. The base resin is a mixture of epoxy resin and polyurethane, a weight percentage of the epoxy resin in the base resin is greater than or equal to 50%, and the epoxy resin limits the polyurethane in a structure formed by curing of the base resin. According to the technical solution of the present application, soldering can be performed directly by solder paste, and good flexibility is brought.

## Claims

### Claim 1

A conductive paste, comprising: a base resin, a solvent, a conductive filler, a curing agent, and an auxiliary agent,
wherein the base resin is a mixture of epoxy resin and polyurethane, a weight percentage of the epoxy resin in the base resin is greater than or equal to 50%, and the epoxy resin limits the polyurethane in a structure formed by curing of the base resin
wherein the conductive paste further comprises a low-molecular weight polyol,
wherein the curing agent is blocked polyisocyanate, and the polyurethane, the low-molecular weight polyol, and the blocked polyisocyanate are reacted during a heat curing process to form a flexible three-dimensional net structure; and
wherein the conductive paste comprises 3 wt % to 15 wt % of the base resin, 5 wt % to 20 wt % of the solvent, 60 wt % to 85 wt % of the conductive filler, 3 wt % to 15 wt % of the low-molecular weight polyol, 3 wt % to 10 wt % of the blocked polyisocyanate, and 0.2 wt % to 10 wt % of the auxiliary agent.

### Claim 2 (depends on 1)

The conductive paste according to claim 1, wherein the epoxy resin has a softening point above 100° C., an epoxide equivalent higher than 5000 g/eq, and a molecular weight higher than 10000 g/mol.

### Claim 3 (depends on 1)

The conductive paste according to claim 1, wherein the polyurethane has an elongation rate higher than 200% and a Kofler melting point above 70° C.

### Claim 4 (depends on 1)

The conductive paste according to claim 1, wherein the conductive filler is ball silver powder with a particle size ranging from 400 nm to 600 nm.

### Claim 5 (depends on 1)

The conductive paste according to claim 1, wherein the low-molecular weight polyol is at least one of polyethylene glycol or polypropylene glycol.

### Claim 6 (depends on 1)

The conductive paste according to claim 1, wherein the blocked polyisocyanate is one selected from a group consisting of blocked toluene diisocyanate, blocked hexamethylene diisocyanate, blocked diphenylmethane diisocyanate, blocked isophorone diisocyanate, blocked xylylene diisocynate, and blocked polyphenylmethane polyisocyanate, or a mixture of at least two selected from the group.

### Claim 7 (depends on 1)

An electronic device, comprising a substrate and a conducting circuit located on the substrate, wherein the conducting circuit is formed by printing and heat curing of the conductive paste according to claim 1.

### Claim 8 (depends on 7)

The electronic device according to claim 7, further comprising an electronic component soldered to the conducting circuit by solder paste.