JP-2026074545-A - Conductive inks and printed materials

Abstract

[Problem] To provide a conductive ink that contributes to reducing environmental impact and can form a conductive layer with excellent conductivity. [Solution] The conductive ink of the present invention is a conductive ink for flexographic printing, offset printing, or screen printing, and is curable by active energy rays. The conductive ink of the present invention comprises conductive particles and a binder component. The binder component comprises a polyfunctional polymerizable compound having a dendrimer structure and/or a hyperbranch structure. The content of the polyfunctional polymerizable compound is 1 part by mass or more per 100 parts by mass of the total amount of conductive particles. [Selection Diagram] None

Inventors

• 高岸 進
• 森 誠之

Assignees

• 高岸 進
• 株式会社GOCCO.

Dates

Publication Date

20260507

Application Date

20241021

Claims (14)

1. It contains conductive particles and binder components, The binder component comprises a polyfunctional polymerizable compound having a dendrimer structure and/or a hyperbranched structure. The content of the polyfunctional polymerizable compound is 1 part by mass or more per 100 parts by mass of the total amount of conductive particles. Active energy ray-curable conductive ink for flexographic printing, offset printing, or screen printing.
2. The active energy ray-curable conductive ink according to claim 1, wherein the polyfunctional polymerizable compound has 6 to 30 polymerizable functional groups.
3. The active energy ray-curable conductive ink according to claim 1 or 2, wherein the polyfunctional polymerizable compound has a (meth)acryloyl group as a polymerizable functional group.
4. The active energy ray-curable conductive ink according to claim 3, wherein the polyfunctional polymerizable compound is a polyester (meth)acrylate compound.
5. The active energy ray-curable conductive ink according to claim 1 or 2, wherein the content of the polyfunctional polymerizable compound is 3 to 20% by mass relative to the total amount of the active energy ray-curable conductive ink.
6. The active energy ray-curable conductive ink according to claim 1 or 2, wherein the content of the conductive particles is 60 to 90% by mass relative to the total amount of the active energy ray-curable conductive ink.
7. The active energy ray-curable conductive ink according to claim 1 or 2, wherein the content of the polyfunctional polymerizable compound is 5% by mass or more based on 100% by mass of the total amount of the binder component.
8. An active energy ray-curable conductive ink according to claim 1 or 2, comprising an acyl phosphine oxide photopolymerization initiator, a photoactive oxime photopolymerization initiator, and a quinone photopolymerization initiator.
9. The active energy ray-curable conductive ink according to claim 1 or 2, comprising a phosphate ester-based dispersant.
10. An active energy ray-curable conductive ink according to claim 1 or 2, for use in offset printing, wherein the binder component further comprises epoxy (meth)acrylate.
11. The active energy ray-curable conductive ink according to claim 1 or 2, for use in waterless offset printing.
12. The device comprises a substrate and a conductive printing layer provided on at least one surface of the substrate. The conductive printed layer comprises conductive particles and a binder component. A printed material wherein the binder component comprises a crosslinked structure derived from a polyfunctional polymerizable compound having a dendrimer structure and/or a hyperbranched structure.
13. A communication device comprising the printed material described in claim 12.
14. An antenna comprising the printed material described in claim 12.

Description

This invention relates to conductive inks and printed materials. Conventionally, conductive layers used in electromagnetic shielding for PDP displays, conductive circuits in printed circuit boards, and antenna circuits for RFID (Radio Frequency Identification) were formed by etching. However, etching requires a photolithograph and the disposal of waste liquids such as etching solutions, resulting in high manufacturing costs and a significant environmental impact. Therefore, there was a need for a method to form conductive layers without using etching. Methods for forming conductive layers without using etching include dry methods such as vacuum deposition, chemical deposition, and ion sputtering of metals; sintering methods that form a conductive layer by printing and sintering using a conductive paste containing nano-sized conductive metals; and printing methods that form a conductive layer by printing using conductive ink containing conductive metals and evaporating the solvent. However, the above dry methods cannot ensure sufficient thickness of the conductive layer, resulting in insufficient conductivity. Furthermore, while the above sintering methods can form a thicker conductive layer than the dry methods, the conductivity is insufficient to meet the requirements of conductive circuits. One known printing method involves using a solvent-curing conductive ink containing metal particles, resin varnish, and a solvent (see Patent Document 1). However, solvent-curing conductive inks have the problem of solvent evaporation during drying. Another known printing method involves using a conductive ink primarily composed of water, containing metal ultrafine particles, polymer latex, and polyoxyalkylene alkylamine, to transfer an ink coating formed on a silicone resin surface to a printing substrate (see Patent Document 2). However, water-based conductive inks require drying, which takes time. Therefore, there is a need for a method using conductive inks that can be cured in a short time and with reduced environmental impact, such as by ultraviolet light. As an example of the above-mentioned active energy ray-curable conductive ink, an active energy ray-curable conductive ink is known that contains a conductive substance, a (meth)acrylate compound having a vinyl ether group as a binder component, and an active energy ray polymerizable compound (see Patent Document 3). Patent Document 3 also describes that the ink exhibited good printability and low resistance values of the printed conductive circuits when used in flexographic printing. Japanese Patent Publication No. 2010-047649Japanese Patent Publication No. 2012-188558Japanese Patent Publication No. 2008-189758 [Conductive ink] The conductive ink of the present invention comprises at least conductive particles and a binder component. The conductive ink of the present invention may also contain other components in addition to the above components. The above-mentioned conductive ink is an active energy ray curing type ink. Upon irradiation with active energy rays, the polymerizable compounds (such as the polyfunctional polymerizable compounds described later) contained in the binder component polymerize, harden, and solidify, thereby forming a conductive layer with electrical conductivity. Examples of the active energy rays mentioned above include ionizing radiation such as alpha rays, beta rays, gamma rays, neutron rays, and electron beams, as well as ultraviolet rays, with ultraviolet rays being particularly preferred. In other words, the active energy ray-curable conductive ink is preferably an ultraviolet-curable conductive ink. (Conductive particles) The conductive layer formed by the conductive ink containing the conductive particles has conductivity. From the viewpoint of forming a conductive layer with excellent conductivity, metal particles are preferred as the conductive particles. Only one type of conductive particle may be used, or two or more types may be used. Examples of metals that constitute the above-mentioned metal particles include gold, silver, copper, nickel, zinc, tin, bismuth, and indium. Only one of these metals may be used, or two or more may be used. Specifically, examples of the above-mentioned metal particles include copper particles, silver particles, nickel particles, silver-coated copper particles, gold-coated copper particles, silver-coated nickel particles, gold-coated nickel particles, silver-coated alloy particles, tin-coated copper particles, tin-coated nickel particles, and solder particles. Among these metal particles, silver-coated copper particles and silver particles are preferred from the viewpoint of forming a conductive layer with excellent conductivity. The shapes of the conductive particles mentioned above include spherical (perfectly spherical, ellipsoidal, potato-shaped, etc.), flake-shaped (scale-like), dendritic, fibrous, and amorphous (polyhedral). Among these, spherical and flake-shaped particles are preferred