阅读说明：本技术 一种适合织物丝网印刷的纳米碳导电油墨及其制备方法 (Nano carbon conductive ink suitable for fabric screen printing and preparation method thereof ) 是由 晏雄 蒋红利 胡吉永 于 2020-04-23 设计创作，主要内容包括：本发明公开了一种适合织物丝网印刷的纳米碳导电油墨及其制备方式。所述纳米碳导电油墨的原料包括以质量百分比计的纳米碳导电材料,聚氨酯弹性体,溶剂,消泡剂及流平剂。制备方法为：在加热搅拌的条件下,将聚氨酯弹性体颗粒加入到溶剂中,充分搅拌后得到聚合物基质溶液；在聚合物基质溶液中加入纳米碳导电材料、消泡剂和流平剂,进行室温搅拌和浴超声处理,制备得均匀分散的纳米碳导电油墨。所述导电油墨能够在织物、薄膜、纸张等柔性承印基材上丝网印刷,具有分散均匀、制备方法简单、生产成本低、可规模化生产等优点,可为柔性纺织智能材料提供良好的基材。(The invention discloses a nano carbon conductive ink suitable for fabric screen printing and a preparation method thereof. The raw materials of the nano carbon conductive ink comprise nano carbon conductive materials, polyurethane elastomers, solvents, defoaming agents and flatting agents in percentage by mass. The preparation method comprises the following steps: under the condition of heating and stirring, adding polyurethane elastomer particles into a solvent, and fully stirring to obtain a polymer matrix solution; adding a nano carbon conductive material, a defoaming agent and a flatting agent into the polymer matrix solution, and carrying out room-temperature stirring and bath ultrasonic treatment to prepare the uniformly dispersed nano carbon conductive ink. The conductive ink can be used for screen printing on flexible printing substrates such as fabrics, films and paper, has the advantages of uniform dispersion, simple preparation method, low production cost, large-scale production and the like, and can provide a good substrate for flexible intelligent textile materials.)

1. The nano-carbon conductive ink suitable for fabric screen printing is characterized by comprising, by mass, 0.5-15% of a nano-carbon conductive material, 10-20% of a polyurethane elastomer, 70-80% of a solvent, 0.2-1% of a defoaming agent and 0.2-1% of a leveling agent.

2. The nanocarbon conductive ink of claim 1, wherein the nanocarbon conductive material comprises at least one of carbon nanotubes and graphene.

3. The nanocarbon conductive ink of claim 2, wherein the carbon nanotubes have an outer diameter of 8 to 15nm, an inner diameter of 3 to 6nm, and a length of 3 to 12 μm; the thickness of the graphene is 3-8nm, and the sheet diameter is 20-50 mu m.

4. The nanocarbon conductive ink of claim 1, wherein the polyurethane elastomer is a thermoplastic polyurethane elastomer.

5. The nanocarbon conductive ink according to claim 1, wherein the solvent is any one of N-methylpyrrolidone and dimethylformamide.

6. The nanocarbon conductive ink of claim 1, wherein the antifoaming agent is BYK-052N or BYK-065.

7. The nanocarbon conductive ink of claim 1, wherein the leveling agent is BYK-333.

8. The method for preparing the nanocarbon conductive ink suitable for screen printing of fabrics according to any one of claims 1 to 7, comprising:

step 1): under the condition of heating and stirring, adding polyurethane elastomer particles into a solvent, and fully stirring to obtain a polymer matrix solution;

step 2): adding a nano carbon conductive material, a defoaming agent and a flatting agent into the polymer matrix solution, and carrying out room-temperature stirring and bath ultrasonic treatment to prepare the uniformly dispersed nano carbon conductive ink.

9. The preparation method of claim 8, wherein the heating temperature in the step 1) is 30-60 ℃, the stirring speed is 500-1000 rpm, and the stirring time is 1-2 h.

10. The method for preparing the nanocarbon conductive ink according to claim 8, wherein the stirring time in the step 2) is 1-2 hours; the ultrasonic treatment time is 30-90 min, and the treatment temperature is 20-40 ℃.

Technical Field

The invention belongs to the field of functional printing ink and preparation thereof, and particularly relates to a preparation method of nano carbon conductive printing ink suitable for fabric screen printing.

Background

In recent years, with the rapid development of the internet of things and intelligent interaction technology, the development and application of flexible wearable electronic equipment are receiving wide attention, and especially the demand of the flexible wearable electronic equipment in the application fields of national defense and military, medical monitoring, intelligent sensing and the like is increasing continuously. Compared with flexible base materials such as silicon rubber and plastic films, textiles which are visible everywhere in life have ideal physical and mechanical properties, air permeability and durability, and can bear twisting and bending actions at any angle, so that the textile can better fit human body curves and meet the requirements of human body movement, and therefore the application of the textile base materials can better meet the research and development targets of wearable electronic equipment. Among various preparation methods of the conductive fabric, the silk-screen printing as an additive manufacturing method can realize excellent conductivity and flexibility on the premise of not influencing the mechanical property of a fabric substrate, and has the advantages of low cost, simple preparation flow, large-scale production and the like.

At present, conductive inks used for screen printing are mainly classified into metal-based conductive inks and carbon-based conductive inks. Although metal-based conductive inks such as copper, silver, nickel and the like have good conductive performance, the metal-based conductive inks are high in cost, easy to oxidize, easy to fall off from the surface of a substrate, and cause heavy metal pollution, skin allergy and the like. The carbon-based conductive ink such as graphite, carbon black, carbon nanotubes, graphene and the like has high conductivity and chemical stability and is widely applied to the field of printed electronics, wherein the carbon nanotubes have high conductivity and high length-diameter ratio, and the graphene has excellent mechanical properties and high carrier mobility, so that the carbon-based conductive ink is suitable for forming a stable mesh-shaped conductive network on the surface of a porous rough fabric. Therefore, the preparation of the nano carbon conductive ink suitable for the screen printing of the fabric substrate has important significance for the research and development of flexible wearable electronic equipment.

The existing carbon-based conductive ink technology has the following main problems: a cumbersome pretreatment process is required to improve the uniformity of the conductive ink, or a long treatment process is required to achieve good adhesion of the conductive ink to the substrate. For example, patent CN110358369A discloses a method for preparing graphene and carbon nanotube conductive ink for inkjet, which includes ball-milling carbon-based conductive particles at room temperature, performing primary selection, washing, sorting and collecting on the mixture to obtain a conductive unit mixed dispersion, and adding a linking agent and an auxiliary agent to obtain a conductive ink with uniform mixing and proper viscosity. Patent CN106876155A discloses a preparation method of a conductive cotton fabric based on carbon nano tubes, in the method, the cotton fabric is immersed into carbon nano tube dispersion liquid at 130-140 ℃ for heat treatment for 60-100 min, and then is dried at 100 ℃, although the prepared conductive cotton fabric has excellent conductivity, the inherent mechanical property of the fabric can be seriously influenced by long-time hydrothermal high-temperature treatment.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: provides a nano carbon conductive ink suitable for fabric screen printing and a preparation method thereof, so as to overcome the defect of complicated and long preparation procedures in the prior art.

In order to solve the technical problems, the invention provides a nano carbon conductive ink suitable for fabric screen printing, which is characterized in that raw materials comprise, by mass, 0.5-15% of a nano carbon conductive material, 10-20% of a polyurethane elastomer, 70-80% of a solvent, 0.2-1% of a defoaming agent and 0.2-1% of a leveling agent.

Preferably, the nanocarbon conductive material includes at least one of carbon nanotubes and graphene.

More preferably, the carbon nano tube has an outer diameter of 8-15nm, an inner diameter of 3-6nm and a length of 3-12 μm; the thickness of the graphene is 3-8nm, and the sheet diameter is 20-50 mu m.

Preferably, the polyurethane elastomer is a thermoplastic polyurethane elastomer.

The polyurethane elastomer is thermoplastic polyurethane elastomer particles, is a conventional commercially available product, and is preferably a polyester type thermoplastic polyurethane elastomer in consideration of tensile properties and wear resistance of the cured conductive ink.

Preferably, the solvent is any one of N-methylpyrrolidone and dimethylformamide, which are commercially available products, and N-methylpyrrolidone is preferred in view of stability and safety of the conductive ink, and is available from national chemical agents ltd.

Preferably, the defoaming agent is BYK-052N or BYK-065.

Preferably, the leveling agent is BYK-333.

The invention also provides a preparation method of the nano carbon conductive ink suitable for the fabric screen printing, which comprises the following steps:

step 1): under the condition of heating and stirring, adding polyurethane elastomer particles into a solvent, and fully stirring to obtain a polymer matrix solution;

step 2): adding a nano carbon conductive material, a defoaming agent and a flatting agent into the polymer matrix solution, and carrying out room-temperature stirring and bath ultrasonic treatment to prepare the uniformly dispersed nano carbon conductive ink.

Preferably, the heating temperature in the step 1) is 30-60 ℃, the stirring speed is 500-1000 rpm, and the stirring time is 1-2 h.

Preferably, the stirring time in the step 2) is 1-2 h; the ultrasonic treatment time is 30-90 min, and the treatment temperature is 20-40 ℃.

The nano carbon conductive material comprises at least one of carbon nano tubes and graphene. Wherein the preferred sizes of the carbon nanotubes are: the outer diameter is 8-15nm, the inner diameter is 3-6nm, and the length is 3-12 mu m; preferred dimensions of the graphene are: the thickness is 3-8nm and the sheet diameter is 20-50 μm.

The polyurethane elastomer is thermoplastic polyurethane elastomer particles, is a conventional commercial product, is preferably a polyester type thermoplastic polyurethane elastomer in view of tensile property and wear resistance of the cured conductive ink, and is purchased from basf, germany.

The solvent is one of N-methyl pyrrolidone and dimethylformamide, is a commercially available product, and is preferably N-methyl pyrrolidone which is purchased from national chemical agents, Inc. in consideration of stability and safety of the conductive ink.

The defoaming agent is BYK-052N or BYK-065, is purchased from BYK company in Germany, can effectively eliminate bubbles generated in the ink in the stirring and printing processes, and improves the uniformity and the evenness of a printing film layer.

The leveling agent is BYK-333, is purchased from BYK company in Germany, can improve the leveling performance of the printing ink, and can prevent the defects of shrinkage cavity, orange peel and the like during printing.

The conductive ink has the advantages of simple preparation process, low cost, proper viscosity and uniformity, and suitability for screen printing process of flexible substrates such as fabrics. The nano carbon conductive ink prepared by the invention has excellent conductivity, stability, dispersion uniformity and proper viscosity, and does not generate layering of the conductive ink or agglomeration of conductive particles after being stored for a long time, thereby being very suitable for a screen printing process of a flexible substrate.

Compared with the prior art, the invention has the beneficial effects that:

(1) the preparation method disclosed by the invention is short in preparation flow, convenient in process operation, low in equipment and material cost, small in environmental pollution, suitable for large-scale green production and good in engineering significance and economic benefit.

(2) The invention adopts the nano carbon material as the conductive filler, and has excellent conductive performance, mechanical property and stability due to the unique structure and the single carbon element. Compared with metal conductive ink, the nano carbon conductive ink has higher oxidation resistance and corrosion resistance, can form a highly interconnected conductive network, and reduces the surface resistance by 8-10 orders of magnitude after screen printing on the surface of porous rough fabric.

(3) The conductive ink prepared by the invention is suitable for a screen printing process, is simple to operate, has low cost, is not limited by the size and the shape of a printing stock, can be printed on the surfaces of various flexible base materials such as common fabrics, films, paper and the like, and has the advantages of simple and easy curing mode and high production efficiency. The screen printing precision and the quality of the ink are high, and when the printing line width of the fabric surface is 0.3mm, a continuous conductive path can be formed.

(4) The nano carbon conductive ink adopts the thermoplastic polyurethane elastomer as the matrix, has proper viscosity, good printing film forming property and strong adhesive force with the fabric base material, and the printed film layer has excellent flexibility and wear resistance.

Drawings

FIG. 1 shows the surface resistance of the original fabric and the conductive ink prepared in examples 1 to 4 after screen printing on the surface of the fabric substrate;

FIG. 2 is a comparative scanning electron micrograph of the conductive inks prepared according to examples 1-4 after screen printing on a surface of a textile substrate;

FIG. 3 is a representation of the conductive ink prepared in example 3 after screen printing on a nylon coated fabric surface;

FIG. 4 is a graph showing the surface resistance change of the nylon fabric of example 5 after screen printing.

Detailed Description

In order to make the invention more comprehensible, preferred embodiments are described in detail below with reference to the accompanying drawings.