Composite nano-catalyst printing ink and application thereof

Abstract

The invention discloses composite nano-catalyst ink and application thereof, the composite nano-catalyst ink comprises a first part and a second part which are mixed, the first part is a mixture of a metal nano-material and an organic solvent, and the second part is an ultraviolet-curable binder; the metal nano material is one of silver nano particles, silver nano colloid and copper nano colloid. The composite nano-catalyst ink is used for preparing a conductive pattern on a flexible substrate. According to the catalyst ink, the preparation method of the touch sensing film can be simplified and optimized, a high-resolution touch film conductive pattern is formed through coating, exposure and development of the composite nano catalyst ink containing the metal nanoparticles, and the curing step can be omitted. The catalyst ink does not use palladium acetate or other palladium components, so that on one hand, the cost can be reduced; on the other hand, the problem that catalyst ink has extra curing time and curing steps can be solved, and meanwhile the problem of base material embrittlement caused by the extra curing time can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible touch screens, and in particular to a composite nano-catalyst ink and applications thereof. Background Art

[0002] Traditional resistive or capacitive touchscreens utilize a material that is both transparent and conductive. As the demand for these products grows, the demand for these devices and systems may require increasingly efficient methods for producing these devices and systems. ITO (indium tin oxide) conductive glass is widely used due to its conductivity and transparency. However, ITO faces challenges with raw material availability, cost, a higher average resistivity compared to other materials, and film brittleness. Indium, a rare earth metal mined and produced only in China, further exacerbates its limited supply. Furthermore, ITO production via vapor deposition yields a brittle film that is less rigid than copper and exhibits poor conductivity. This process is expensive and cumbersome, making ITO a less viable option for touchscreen production. Furthermore, ITO electrode patterns in touch sensors can only be printed at specific sizes and resolutions, and conventional printing technologies only support specific electrode pattern structures around 25 microns.

[0003] The preparation of metallic conductive patterns requires a conductive pattern, which in turn relies on catalysts or catalyst inks. Commonly used catalysts are precious metal catalysts, such as gold, silver, copper, palladium, and platinum. Liquid catalysts are primarily palladium and silver. The preparation of silver nanodispersions is relatively mature, but their applications are primarily in organic catalysis, the printing and dyeing industry, environmental sterilization, spectroscopy, and basic catalytic research in electrochemical reactions. For coating catalysis, silver nanodispersions are difficult to apply directly due to their high surface energy and dispersibility. Therefore, silver nanodispersions must be redispersed and formulated into a conductive ink for catalyst coating, whereas palladium catalysts can be directly formulated into a coating liquid. However, the high cost of palladium metal and issues with raw material supply significantly reduce the advantages of palladium catalysts. Therefore, the development of catalyst inks is particularly important.

[0004] Generally, conductive or catalytic catalyst inks can be in the form of liquids, suspensions, mixtures, or gels, and can contain nanometal particles, nanometal oxides, and the like. Taking palladium acetate as an example, in some cases, palladium is relatively expensive and in short or unreliable supply. Furthermore, photocuring requires additional curing time and steps, and prolonged curing can lead to substrate embrittlement, hindering further processing. Furthermore, palladium is initially deposited onto the substrate as molecular domains, which grow uncontrollably in three dimensions, leading to the formation of a rough surface during the subsequent metal deposition stage. Summary of the Invention

[0005] The purpose of the present invention is to address the defects of existing palladium-containing catalyst inks that require additional curing time and steps, and to propose a composite nano-catalyst ink to solve the above problems.

[0006] To solve the above problems, the present invention is achieved through the following technical solutions:

[0007] A composite nanocatalyst ink is provided. The catalyst ink comprises a first part and a second part, wherein the first part is a mixture of a metal nanomaterial and an organic solvent, and the second part is a UV-curable binder. The metal nanomaterial is at least one of silver nanoparticles, silver nanocolloids, and copper nanocolloids. The silver nanoparticles can be prepared by the following method, or commercially available nanosilver can be used.

[0008] Specifically, the first part and the second part may be stirred at a rotation speed of 550 to 800 rpm for 1 to 2 hours to obtain the composite nano-catalyst ink.

[0009] Furthermore, a composite nano-catalyst ink: the first part accounts for 55.0-65.0wt%.

[0010] Furthermore, a composite nano-catalyst ink: the organic solvent is selected from at least one of acetone, cyclohexanone, diethylene glycol dimethyl ether, ethylene glycol methyl ether, toluene, xylene, ethylene glycol acetate, and butyl acetate.

[0011] Furthermore, a composite nano-catalyst ink: the second part is a UV-curable binder, which contains acrylic resin, urethane, a cross-linkable polymer and a photoinitiator.

[0012] Furthermore, a composite nano-catalyst ink: the silver nanoparticles are prepared by reducing silver nitrate, and the preparation method is as follows:

[0013] 40.0-60.0 mL of ethylene glycol was added to a container, followed by 5.0-10.0 g of polyvinyl pyrrolidone and 100.0-300.0 mg of silver nitrate. The mixture was refluxed at 150-160° C. for 1-2 hours to obtain silver nanoparticles with a particle size of 20.0-200.0 nm.

[0014] Furthermore, a composite nano-catalyst ink is provided: the silver nanoparticles are prepared by reducing with sodium citrate, and the preparation method is as follows:

[0015] 150.0-300.0 mg of silver nitrate and 5.0-10.0 g of polyvinyl pyrrolidone are added to 100.0-150.0 mL of sodium citrate solution to react and obtain silver nanoparticles with a particle size of 10.0-100.0 nm.

[0016] Furthermore, a composite nano-catalyst ink: the preparation method of the copper nano-colloid comprises the following steps:

[0017] (1) preparing a copper solution: adding citric acid and xylitol to a copper sulfate solution to prepare a copper solution, wherein the concentration of copper sulfate in the copper solution is 0.05 to 0.2 mol / L, the concentration of citric acid is 0.1 to 0.25 mol / L, and the concentration of xylitol is 0.2 to 0.4 mol / L;

[0018] (2) preparing a reducing agent solution: dissolving sodium borohydride and hypophosphorous acid to form a reducing agent solution, wherein the concentration of sodium borohydride in the reducing agent solution is 0.01 to 0.03 mol / L, and the concentration of hypophosphorous acid is 0.1 to 0.3 mol / L;

[0019] (3) The pH of the copper solution is adjusted to 3.5-4.5, and then the reducing agent solution is added dropwise thereto and stirred to obtain copper nanocolloids with an average particle size of 10-20 nm.

[0020] Provided is a use of a composite nano-catalyst ink, wherein the composite nano-catalyst ink is used to prepare a flexible metal grid conductive pattern on a flexible substrate.

[0021] Furthermore, a use of a composite nano-catalyst ink: the preparation method of the conductive pattern is:

[0022] S1, solidified layer coating: applying the composite nano-catalyst ink to the surface of the flexible substrate by coating, and drying after coating to obtain a solidified base flexible substrate;

[0023] S2, coating a protective layer: coating the protective liquid on the solidified flexible substrate and drying to form a protective layer;

[0024] S3, exposure: placing the flexible substrate with the protective layer formed thereon under a mask of an exposure machine, and exposing the substrate to form a pattern;

[0025] S4, development: immersing the exposed flexible substrate in a developer to form a circuit pattern;

[0026] S5. Chemical copper plating: The developed flexible substrate is cleaned and dried, and then placed in a chemical copper plating solution for copper plating to form a flexible metal grid conductive pattern.

[0027] Furthermore, a use of a composite nano-catalyst ink: the preparation method of the conductive pattern is:

[0028] S1, solidified layer coating: applying the composite nano-catalyst ink to the surface of the flexible substrate by coating, and drying at 50-90° C. for 2-10 minutes after coating to obtain a solidified base flexible substrate;

[0029] Wherein: the coating method is one of roller coating, slit coating, and spin coating; the flexible substrate is selected from one of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cellulose acetate (TAC), alicyclic hydrocarbon (COP), polymethyl methacrylate (PMMA), polyimide (PI), biaxially oriented polypropylene (BOPP), polypropylene, polycarbonate, and glass;

[0030] S2. Protective layer coating: coating the protective liquid on the solidified flexible substrate by roller coating, slit coating or spin coating, and drying at 60-90° C. for 2-10 minutes to form a protective layer;

[0031] S3. Exposure: Place the flexible substrate with the protective layer under the mask of the exposure machine and irradiate it with ultraviolet light of 365nm wavelength and energy of 30-150mj / cm 2 , forming a pattern by exposure;

[0032] S4, development: immersing the exposed flexible substrate in a developer to form a circuit pattern;

[0033] S5. Chemical copper plating: The developed flexible substrate is cleaned and dried, and then placed in a chemical copper plating solution for copper plating to form a flexible metal grid conductive pattern.

[0034] Beneficial effects of the present invention:

[0035] (1) The composite nanocatalyst ink provided by the present invention can simplify and optimize the preparation method of the touch sensor film. By coating, exposing, and developing the composite nanocatalyst ink containing metal nanoparticles to form a high-resolution touch film conductive pattern, the curing step can be eliminated from the traditional method, thereby saving related time and costs.

[0036] (2) The composite nano-catalyst ink of the present invention does not use palladium acetate or other palladium components, which can effectively reduce costs on the one hand; on the other hand, it can also solve the problem of the catalyst ink having additional curing time and curing steps, and at the same time avoid the problem of substrate embrittlement caused by the additional curing time. DETAILED DESCRIPTION

[0037] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative work are within the scope of protection of the present invention.

[0038] Example 1

[0039] Provided is a composite nanocatalyst ink, comprising a first part and a second part, wherein the first part is a mixture of silver nanoparticles (metal nanomaterial) and cyclohexanone (organic solvent), and the second part is a UV-curable binder comprising an acrylic resin, urethane, a cross-linkable polymer, and a photoinitiator. The first part accounts for 60.0 wt% of the composite nanocatalyst ink.

[0040] Wherein: the silver nanoparticles are prepared by reducing silver nitrate, and the preparation method thereof is as follows:

[0041] 50.0 mL of ethylene glycol was added to a container, followed by 8.0 g of polyvinyl pyrrolidone and 200.0 mg of silver nitrate. The mixture was refluxed at 160°C for 1.5 hours to produce silver nanoparticles with a particle size of 20.0 to 200.0 nm. Specifically, the first and second parts were stirred at 650 rpm for 1 hour to obtain the composite nanocatalyst ink.

[0042] Example 2

[0043] Provided is a composite nanocatalyst ink, comprising a first part and a second part, wherein the first part is a mixture of silver nanoparticles (metal nanomaterial) and diethylene glycol dimethyl ether (organic solvent), and the second part is a UV-curable binder comprising an acrylic resin, urethane, a cross-linkable polymer, and a photoinitiator; the first part accounts for 55.0 wt% of the composite nanocatalyst ink;

[0044] The silver nanoparticles are prepared by sodium citrate reduction, as follows: 200.0 mg of silver nitrate and 7.0 g of polyvinyl pyrrolidone are added to 120.0 mL of sodium citrate solution for reaction to produce silver nanoparticles with a particle size of 10.0 to 100.0 nm. The first and second parts are stirred at 800 rpm for 2 hours to obtain the composite nanocatalyst ink.

[0045] Example 3

[0046] Provided is a composite nanocatalyst ink, comprising a first part and a second part, wherein the first part is a mixture of copper nanocolloid (metal nanomaterial) and xylene (organic solvent), and the second part is a UV-curable binder comprising an acrylic resin, urethane, a cross-linkable polymer, and a photoinitiator; the first part accounts for 65.0 wt% of the composite nanocatalyst ink;

[0047] Wherein: the preparation method of the copper nanocolloid comprises the following steps:

[0048] (1) preparing a copper solution: adding citric acid and xylitol to a copper sulfate solution to prepare a copper solution, wherein the concentration of copper sulfate in the copper solution is 0.1 mol / L, the concentration of citric acid is 0.2 mol / L, and the concentration of xylitol is 0.3 mol / L;

[0049] (2) preparing a reducing agent solution: dissolving sodium borohydride and hypophosphorous acid to form a reducing agent solution, wherein the concentration of sodium borohydride in the reducing agent solution is 0.02 mol / L and the concentration of hypophosphorous acid is 0.18 mol / L;

[0050] (3) The pH of the copper solution was adjusted to 4.0, and the reducing agent solution was then added dropwise thereto and stirred for 45 minutes to produce a copper nanocolloid with an average particle size of 15.0 nm. Specifically, the first and second parts were stirred at 550 rpm for 1 hour to obtain the composite nanocatalyst ink.

[0051] application:

[0052] The composite nano-catalyst ink of Example 1 is used to prepare a flexible metal grid conductive pattern on a flexible substrate. The preparation process is as follows:

[0053] S1, solidified layer coating: the composite nano-catalyst ink is applied to the surface of the flexible substrate (specifically, polyimide) by roller coating, and then dried at 70° C. for 5 minutes to obtain a solidified base flexible substrate;

[0054] S2. Protective layer coating: coating the protective liquid (water-based polymer coating) on ​​the cured base flexible substrate by roller coating, and drying in an oven at 70° C. for 5 minutes to form a protective layer;

[0055] S3. Exposure: Place the flexible substrate with the protective layer formed above under the mask of the exposure machine and irradiate it with ultraviolet light of 365nm wavelength and energy of 30-150mj / cm 2 , thereby exposing to form a pattern;

[0056] S4. Development: Immersing the exposed flexible substrate in a developer solution. After a period of time, the uncured portion of the cured coating is washed away by the developer solution, leaving the remaining portion as the circuit pattern. The developer solution comprises 10.0-20.0 wt % of diethanolamine and 5.0-10.0 wt % of an inorganic base (e.g., potassium carbonate or sodium carbonate).

[0057] S5. Chemical copper plating: The developed flexible substrate is cleaned with deionized water and blown dry, and then placed in a chemical copper plating solution and copper plated at 30-60° C. for 2-10 minutes to form a flexible metal grid conductive pattern.

[0058] The above preferred embodiments of the present invention are only used to explain the present invention and are not used to limit the present invention. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A composite nano-catalyst ink, characterized in that: The catalyst ink comprises a first part and a second part, wherein the first part is a mixture of metal nanomaterials and an organic solvent, and the second part is a UV-curable binder; Wherein: the metal nanomaterial is at least one of silver nanoparticles, silver nanocolloids, and copper nanocolloids.

2. A composite nano-catalyst ink according to claim 1, characterized in that: The first part accounts for 55.0-65.0 wt %.

3. The composite nano-catalyst ink according to claim 1, characterized in that: The organic solvent is selected from at least one of acetone, cyclohexanone, diethylene glycol dimethyl ether, ethylene glycol methyl ether, toluene, xylene, ethylene glycol acetate, and butyl acetate.

4. The composite nano-catalyst ink according to claim 1, characterized in that: The second part is a UV-curable adhesive, which contains acrylic resin, urethane, a cross-linkable polymer and a photoinitiator.

5. The composite nano-catalyst ink according to claim 1, characterized in that: The silver nanoparticles are prepared by reducing silver nitrate, and the preparation method is as follows: 40.0-60.0 mL of ethylene glycol was added to a container, followed by 5.0-10.0 g of polyvinyl pyrrolidone and 100.0-300.0 mg of silver nitrate. The mixture was refluxed at 150-160° C. for 1-2 hours to obtain silver nanoparticles with a particle size of 20.0-200.0 nm.

6. The composite nano-catalyst ink according to claim 1, characterized in that: The silver nanoparticles are prepared by sodium citrate reduction, and the preparation method is as follows: 150.0-300.0 mg of silver nitrate and 5.0-10.0 g of polyvinyl pyrrolidone are added to 100.0-150.0 mL of sodium citrate solution to react and obtain silver nanoparticles with a particle size of 10.0-100.0 nm.

7. The composite nano-catalyst ink according to claim 1, characterized in that: The preparation method of the copper nano-colloid comprises the following steps: (1) preparing a copper solution: adding citric acid and xylitol to a copper sulfate solution to prepare a copper solution, wherein the concentration of copper sulfate in the copper solution is 0.05 to 0.2 mol / L, the concentration of citric acid is 0.1 to 0.25 mol / L, and the concentration of xylitol is 0.2 to 0.4 mol / L; (2) preparing a reducing agent solution: dissolving sodium borohydride and hypophosphorous acid to form a reducing agent solution, wherein the concentration of sodium borohydride in the reducing agent solution is 0.01 to 0.03 mol / L, and the concentration of hypophosphorous acid is 0.1 to 0.3 mol / L; (3) The pH of the copper solution is adjusted to 3.5-4.5, and then the reducing agent solution is added dropwise thereto and stirred to obtain copper nanocolloids with an average particle size of 10-20 nm.

8. A use of a composite nano-catalyst ink, characterized in that: The composite nanocatalyst ink according to any one of claims 1 to 7 is used to prepare a flexible metal grid conductive pattern on a flexible substrate.

9. The use of a composite nano-catalyst ink according to claim 8, characterized in that: The preparation method of the conductive pattern is: S1, solidified layer coating: applying the composite nano-catalyst ink to the surface of the flexible substrate by coating, and drying after coating to obtain a solidified base flexible substrate; S2, coating a protective layer: coating the protective liquid on the solidified flexible substrate and drying to form a protective layer; S3, exposure: placing the flexible substrate with the protective layer formed thereon under a mask of an exposure machine, and exposing the substrate to form a pattern; S4, development: immersing the exposed flexible substrate in a developer to form a circuit pattern; S5. Chemical copper plating: The developed flexible substrate is cleaned and dried, and then placed in a chemical copper plating solution for copper plating to form a flexible metal grid conductive pattern.

10. The use of a composite nano-catalyst ink according to claim 9, characterized in that: S1, solidified layer coating: applying the composite nano-catalyst ink to the surface of the flexible substrate by coating, and drying at 50-90° C. for 2-10 minutes after coating to obtain a solidified base flexible substrate; Wherein: the coating method is one of roller coating, slit coating, and spin coating; the flexible substrate is selected from one of polyethylene terephthalate, polyethylene naphthalate, cellulose acetate, alicyclic hydrocarbons, polymethyl methacrylate, polyimide, biaxially oriented polypropylene, polypropylene, polycarbonate, and glass; S2. Protective layer coating: coating the protective liquid on the solidified flexible substrate by roller coating, slit coating or spin coating, and drying at 60-90° C. for 2-10 minutes to form a protective layer; S3. Exposure: Place the flexible substrate with the protective layer under the mask of the exposure machine and irradiate it with ultraviolet light of 365nm wavelength and energy of 30-150mj / cm 2 , forming a pattern by exposure; S4, development: immersing the exposed flexible substrate in a developer to form a circuit pattern; S5. Chemical copper plating: The developed flexible substrate is cleaned and dried, and then placed in a chemical copper plating solution for copper plating to form a flexible metal grid conductive pattern.