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CN-122002708-A - Flexible electronic circuit based on flexography and screen printing and preparation method thereof

CN122002708ACN 122002708 ACN122002708 ACN 122002708ACN-122002708-A

Abstract

The invention discloses a flexible electronic circuit based on flexible printing and screen printing and a preparation method thereof, and belongs to the technical field of flexible electronic circuits. The preparation method comprises the steps of pre-shrinking and corona treatment of a flexible substrate, forming a through hole, printing silver paste on the two sides of the substrate by adopting roll-to-roll flexographic printing to form a conductive circuit and synchronously filling holes, baking and solidifying a silver wire layer, printing an insulating protective layer on the silver wire layer by adopting roll-to-roll screen printing to expose a flat cable end, baking and solidifying the insulating layer, printing and reinforcing the exposed end, and finally carrying out post-treatments such as cutting, testing and the like. The invention adopts the additive process of roll-to-roll continuous production by organically combining flexography and screen printing, replaces the traditional etching reduction method, remarkably simplifies the production flow, improves the production efficiency, reduces the raw material consumption and the equipment cost, reduces the chemical pollution, and has the advantages of high efficiency, low cost and environmental protection.

Inventors

  • CHEN ZHIQIANG
  • CHEN QIANYANG
  • LU ZHAOJING
  • CHEN WEINING
  • MENG YAN

Assignees

  • 宁波圆芯电子有限公司

Dates

Publication Date
20260508
Application Date
20260210

Claims (10)

  1. 1. The preparation method of the flexible electronic circuit based on the flexography and the screen printing is characterized by comprising the following steps: S1, preprocessing a substrate, namely pre-shrinking and corona treatment are carried out on the flexible substrate, and connecting through holes are formed; S2, flexography printing conductive lines, namely printing silver paste on the upper surface and the lower surface of the pretreated base material respectively by adopting a roll-to-roll flexography printer to form a T-face silver line layer and a B-face silver line layer, and synchronously filling the connection conductive holes to realize the electric conduction of the double-face lines; S3, baking and curing the silver wire layer, namely baking and curing the T-face silver wire layer and the B-face silver wire layer; Step S4, screen printing an insulating protective layer, namely printing insulating ink on the surfaces of the T-face silver wire layer and the B-face silver wire layer by adopting a roll-to-roll screen printing machine to form the T-face insulating protective layer and the B-face insulating protective layer, and exposing a conductive circuit only in the area of the flat cable end; s5, baking and curing the insulating protective layer, namely baking and curing the T-face insulating protective layer and the B-face insulating protective layer; Step S6, the flat cable end is processed, namely a carbon layer and a silver paste layer are printed on the surface of the exposed flat cable end in sequence, and baking and curing are carried out; and S7, post-processing, namely obtaining the flexible electronic circuit based on the flexible printing and the screen printing after post-processing.
  2. 2. The method according to claim 1, wherein in the step S1, the flexible substrate is a PI film or a PET film; When the material of the flexible substrate is a PI film, the pre-shrinking temperature is 160-180 ℃ and the pre-shrinking time is 30-45min; when the material of the flexible substrate is PET film, the pre-shrinking temperature is 150-160 ℃ and the pre-shrinking time is 30-45min.
  3. 3. The method according to claim 1, wherein in the step S2, the printing parameters of the roll-to-roll flexible printer are as follows, the printing speed is 18-22m/min, the printing pressure is 4.8-5.0Pa, the pulling tension is 68-72N, the alignment accuracy is +/-0.05 mm, and the printing ink thickness is 3-5 μm.
  4. 4. The method according to claim 1, wherein in the step S3, the baking and curing parameters of the T-plane silver wire layer are 90-110 ℃ and 3-6min, and the baking and curing parameters of the B-plane silver wire layer are 120-150 ℃ and 25-35min.
  5. 5. The method according to claim 1, wherein in the step S4, the printing parameters of the roll-to-roll screen printer are as follows, the printing speed is 3-6m/min, the printing pressure is 6-7kg/cm2, the pulling tension is 65-75N, the alignment accuracy is + -0.05 mm, and the printing ink thickness is 10-14 μm.
  6. 6. The method according to claim 1, wherein the baking and curing parameters in step S5 are 90-110 ℃ for 8-12min.
  7. 7. The method according to claim 1, wherein the baking and curing parameters in step S6 are 120-140 ℃ for 28-35min.
  8. 8. The method according to claim 1, wherein in the step S7, the post-treatment step includes sequentially performing cutting, electrical measurement, reinforcement, lamination, appearance processing, and appearance inspection.
  9. 9. The method of claim 1, wherein the printing and baking steps in steps S2, S3, S4, S5, and S6 are performed in a line-synchronized manner.
  10. 10. A flexible electronic circuit manufactured by the manufacturing method according to any one of claims 1 to 9, comprising: An insulating base material layer; The T-surface silver wire layer is formed on the upper surface of the insulating substrate layer, is prepared from silver paste through a flexographic printing process and comprises a conductive circuit with a preset pattern; the B-side silver wire layer is formed on the lower surface of the insulating substrate layer, and is prepared from silver paste through a flexographic printing process, and the circuit pattern of the B-side silver wire layer corresponds to the T-side silver wire layer; the connecting via hole is arranged on the insulating substrate layer, and silver paste is filled in the hole to electrically connect the T-face silver wire layer and the B-face silver wire layer; the T-face insulating protection layer is formed on the surface of the T-face silver wire layer and is prepared through a screen printing process and used for covering and protecting the T-face silver wire layer, and the conductive circuit is exposed only in the area of the flat cable end; the B-side insulating protective layer is formed on the surface of the B-side silver wire layer and is prepared through a screen printing process and used for covering and protecting the B-side silver wire layer; The flat cable end head is arranged at one end of the insulating substrate layer, the T-face insulating protective layer in the area is removed, part of the circuit of the T-face silver wire layer is exposed, and a carbon layer and silver paste are printed on the surface of the exposed circuit.

Description

Flexible electronic circuit based on flexography and screen printing and preparation method thereof Technical Field The invention relates to the technical field of flexible electronic circuits, in particular to a flexible electronic circuit based on flexible printing and screen printing and a preparation method thereof. Background Under the background of rapid development of the current flexible electronic technology, flexible circuit boards (FPCs) are increasingly widely applied to the fields of automotive electronics, medical sensing, intelligent robots, flexible display and the like due to the characteristics of being bendable, light and thin, capable of being integrated and the like. Currently, the main methods of manufacturing flexible electronic circuits in the industry remain dominated by conventional "subtractive" etching processes. The process takes a rolled double-sided copper-clad Polyimide (PI) film as a base material, firstly cuts Cheng Piancai, and then carries out more than twenty complex procedures such as drilling, electroless copper plating, electroplating thickening, dry film pasting, exposure, development, etching, film stripping, PI protection film pasting, high-temperature curing, nickel-gold plating, laser cutting appearance, electrical property testing and the like. The process is long in flow and slow in production period, and the investment of fixed assets is huge because the process is dependent on a plurality of sets of large-scale special equipment such as copper-depositing wires, plating wires, an exposure machine, developing, etching and film-removing integrated equipment, gold-plating wires and the like. From the material cost, the process needs to remove about 70% of copper foil in the etching step, and consumes a large amount of dry film, copper deposition liquid medicine, electroplating liquid and etching liquid, so that raw materials are seriously wasted, and the cost is high. In addition, the whole production process, especially the chemical wet processes of copper deposition, electroplating, etching and the like, can generate a large amount of wastewater and waste residues containing heavy metals such as copper, nickel and the like, and is accompanied by organic waste gas emission, thereby having remarkable environmental impact and high environmental protection treatment cost. Meanwhile, printing technology has been applied in the related art as a patterning process, but there are still significant limitations in the use of the printing technology for high-precision flexible electronic circuit manufacturing. Flexography has the advantages of high printing speed (up to 20 m/min), high efficiency and suitability for roll-to-roll continuous production, is mature in the flexible packaging industry, but has few mature technical schemes which are publicly available in China in the manufacturing field of precise conductive lines, particularly in the aspect of electronic-level application for realizing 100-micron-level line width/line distance, and has not been fully excavated and standardized in the aspect of high-precision pattern transfer for circuit manufacturing. On the other hand, although screen printing has the advantages of controllable ink layer thickness, good adhesive force and wide ink selection range, and is applied to products such as membrane switches, electronic element marks and the like, the printed circuit edge of the screen printing has saw-tooth defects, which affect the consistency of electrical performance, and meanwhile, the typical printing speed (about 5 meters/min) is far lower than that of flexography, the production efficiency is limited, and the production of a large-scale and low-cost flexible circuit is difficult to support independently. In summary, the prior art has a dilemma that the conventional subtractive etching process can achieve higher circuit accuracy and reliability, but has a great cost of complex flow, high cost and unfriendly environment, and the single flexography or screen printing technology can not effectively replace the conventional process to achieve efficient, economic and green production on the premise of ensuring the product quality due to insufficient accuracy and reliability or insufficient production efficiency. Therefore, an innovative process route is urgently needed in the field of flexible electronic manufacturing, the advantages of different printing technologies can be organically combined, high-precision (such as + -0.05 mm alignment precision) and high reliability of a circuit are ensured while high-efficiency continuous roll-to-roll production is realized, chemical pollution is fundamentally reduced, material and equipment cost is reduced, and therefore the flexible electronic technology is promoted to develop towards the industrialized direction of more environmental protection and more economy. Disclosure of Invention To overcome the above drawbacks of the prior art, a first object of the present invention