CN105153814B - A kind of preparation method of water base nano silver wire ink - Google Patents

Abstract

The invention discloses a preparation of water-based silver nanowire ink, which consists of: silver nanowire, 0.2-1.5%; sodium carboxymethylcellulose, 0.2-1%; Zonyl@FSO-100, 0.005-0.1% ; polymer dispersant, 0.1‑2%; small molecule leveling agent, 1‑3%; small molecule defoamer, 1‑2%; water, 85.4‑94.495%. After the ink is coated, a conductive film with high conductivity and light transmittance can be obtained by simple treatment, so it can be widely used in the fields of electronic products such as touch screens.

Description

A kind of preparation method of water-based silver nanowire ink

technical field

The invention belongs to the field of conductive ink, and in particular relates to the preparation of water-based silver nanowire ink.

Background technique

Flexible products such as wearable devices are becoming more and more popular. The development of flexible products is inseparable from flexible substrates. However, the current immaturity of flexible substrates has led to a bottleneck in the development of flexible products. Among PEDOT:PSS, graphene, carbon nanotubes, and nanometal wires that can realize flexible conductive substrates, silver nanowires are currently the most likely material for breakthroughs. Therefore, people have carried out a lot of research on silver nanowire conductive film.

To prepare silver conductive film, it is first necessary to formulate silver nanowires into conductive ink, and then make the ink into a film by spraying, rolling, scraping and other means. The performance of the film depends on the performance of the ink and the post-processing process, but it is the performance of the ink that plays a decisive role. In order to develop silver conductive inks with excellent performance, a large number of inks have been formulated. These inks fall into two main categories: organic-based and water-based. Among them, organic inks account for the vast majority, and water-based inks are very few. However, organic solvents will pollute the environment and do not conform to the national environmental protection policy. Environmentally friendly water-based ink is the direction of future development. So, some preliminary work has been done on water-based inks.

In the patent (US8018568B2, US8632700B2, US8723216B2 and US8049333B2) issued by U.S. Cambrios company, thickener hydroxypropyl methylcellulose or propylene glycol, fluorocarbon surfactant and water are used to prepare silver ink. However, the decomposition temperature of hydroxypropyl methylcellulose as high as 300°C and the slow dissolution rate in water make it difficult to remove it by simple heat treatment and solvent immersion after the ink is coated and dried, while high conductivity and light transmittance The thin film requires the ink to be coated and dried to remove other substances except the silver nanowires as much as possible, so the conductivity and light transmission of the thin film are not good. Except for glass substrates that can withstand high temperatures of several hundred degrees, other flexible substrates are not suitable for using this ink. For this reason, people replace the hard-to-remove substance with the substance that removes easily, as patent CN104064282A and CN103965674A. The performance of inks has been improved by using water-based binders and resins that are easily removed by immersion in pure water. However, these inks have the same problem as Cambrios inks: too few types of additives lead to poor coating performance of the ink, which in turn leads to uneven conduction of the film. In order to solve this problem, inks containing various additives have been developed. For example, in patent CN103996455A, the ink contains binder, silicon oxide hydrosol, silicate, organic silicon titanium oxide hydrosol, silane coupling agent, surfactant, UV curable transparent resin, conductive polymer, etc. The coating performance and conductive uniformity of the ink are guaranteed, but the conductivity and light transmittance of the film are greatly affected due to more difficult-to-remove substances. To sum up, the selection of additives for water-based silver nanowire inks is still far from perfect, resulting in poor ink coating performance and coating film performance.

Therefore, how to determine a suitable water-based ink additive to make the performance of the prepared ink meet the standards used in the electronics industry is an urgent problem in the field of transparent conductive inks.

Contents of the invention

The purpose of the present invention is to provide a formulation of water-based silver nanowire ink, which solves the problem of poor additives for water-based inks. The silver line ink developed by the invention has good coating performance, and the prepared film has high and uniform conductivity and high light transmittance, and can be widely used in the field of electronic information. The specific formula of the ink is as follows:

Silver nanowires, 0.2-1.5%;

Sodium carboxymethylcellulose, 0.2-1%;

Zonyl@FSO-100, 0.005-0.1%;

Polymer dispersant, 0.1-2%;

Small molecule leveling agent, 1-3%;

Small molecule defoamer, 1-2%;

Water, 90.4-96.495%.

The silver nanowire used in the present invention has a diameter of 30-50nm and a length of 10-20 μm;

The binder used in the present invention is sodium carboxymethyl cellulose, and the surfactant used is Zonyl@FSO-100;

The polymer dispersant used in the present invention is liquid Spredox series dispersant Spredox D-260, D-320, D-159, D-330, D340, D350, D-141 etc. and other polymer dispersants such as Disper9170 one or a mixture of several;

The small molecule leveling agent used in the present invention is a mixture of one or more of high boiling point solvents such as ethylene glycol dibutyl ether, isopropoxyethanol, propylene glycol methyl ether, isophorone, diacetone alcohol, and DBE;

Small molecular defoamer used in the present invention is 2-hexyl alcohol;

The preparation steps of the ink of the present invention are as follows: dissolving sodium carboxymethyl cellulose in water to form a 1.5% aqueous solution. Determine the composition of the recipe and calculate the amount of each substance needed. Then mix the other ingredients except the sodium carboxymethylcellulose solution evenly and stir for 20 minutes. Then, slowly drop the desired sodium carboxymethylcellulose solution into the stirring ink. After continuing to stir for 30 minutes, filter with a filter membrane with a pore size of 20 μm to obtain the final ink;

Ink coating and post-processing steps of the present invention: adjust the content of sodium carboxymethyl cellulose to obtain viscosity and cohesiveness meeting the requirements of different machines and substrates. The ink is made into films of different shapes by rolling coating, scraping coating, spraying, etc. After drying, put the film flat into distilled water/ethanol=1:1 solution, and take it out after 10 minutes. Put the film flat into a vacuum oven and bake it under vacuum at 110°C for 10 minutes to obtain a silver nanowire conductive film with almost only silver conductive network left; the present invention has the following advantages: (1) the ink contains a variety of different functions Auxiliaries can adjust the ink performance to the required physical parameters of various substrate coatings. Therefore, the ink of the present invention has a good coating effect on various substrates; (2) all the other auxiliaries except silver lines All can be removed by simple solvent immersion, and the final conductive film has almost only silver conductive network, so the light transmittance is high; at the same time, vacuum heating ensures that it can be melted and bonded without being oxidized to form a high-quality conductive network. These make the conductivity and light transmittance of the film made of the ink very high; (3) the amount of silver wire used is small, the raw material is cheap, the preparation process is simple, and it is convenient for large-scale production and use.

Description of drawings

Fig. 1: the silver wire network that forms after the ink coating treatment of the present invention;

specific embodiment

Example:

Silver nanowires with a diameter of 30-50 nm and a length of 10-20 μm are used as conductive substances. Sodium carboxymethyl cellulose was used as binder, Zonyl@FSO-100 was used as surfactant, Spredox D-260 was used as dispersing and anti-settling agent, propylene glycol methyl ether was used as leveling agent, 2-hexyl ethanol was used as defoaming agent, water Prepare the slurry for the solvent;

Sodium carboxymethyl cellulose was formulated as a 1.5% aqueous solution (note: greater concentration would result in too high a viscosity to be taken out). Then determine the content of these components and calculate the mass required for each additive. Add the rest of the material except the sodium carboxymethylcellulose solution into the flask and stir to mix for 20 minutes. Then the sodium carboxymethylcellulose solution was slowly dripped into the slurry, and the stirring was continued for 30 minutes. Finally, the slurry was filtered through a filter membrane with a pore size of 20 μm to obtain the final ink.

The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make many modifications and changes according to the concept of the present invention without creative efforts. All experiments and technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection defined by the claims.

Claims (2)

1. a kind of preparation method of water base nano silver wire ink, which is characterized in that its formula includes：

Nano silver wire, 0.2-1.5%；A diameter of 30-50 nm of the nano silver wire, length is at 10-20 μm；

Sodium carboxymethylcellulose, 0.2-1%；The sodium carboxymethylcellulose is binder；

Fluorocarbon surfactant, 0.005-0.1%；The surfactant be Zonyl@FSO, Zonyl@FSP, Zonyl@FSA, Zonyl@8867L、Zonyl@8857A、Zonyl@ FSN、Zonyl@FS、Zonyl@ FSK、Zonyl@ FSD、Zonyl@ TBS、 One kind in Capstone@FS；

Macromolecule dispersing agent, 0.1-2%；The macromolecule dispersing agent be liquid Spredox dispersants or/and Disper9170 macromolecule dispersing agents；

Small molecule levelling agent, 1-3%；The small molecule levelling agent be butyl cellosolve, isopropoxide ethanol, propylene glycol monomethyl ether, The mixing of one or more of isophorone, diacetone alcohol, DBE high boiling solvents；

Small molecule antifoaming agent, 1-2%；

Water, 90.4-96.495%；

Its preparation process includes：By sodium carboxymethylcellulose it is soluble in water be made into 1.5% aqueous solution；It determines formula composition, calculates Amount needed for each substance；Then the other compositions in addition to carboxymethylcellulose sodium solution are uniformly mixed, are stirred 20 minutes；So Afterwards, required carboxymethylcellulose sodium solution is slowly instilled in the ink in stirring；After continuing stirring 30 minutes, with 20 μm of holes The membrane filtration of diameter obtains final ink.

2. the preparation method of water base nano silver wire ink as described in claim 1, it is characterised in that：It is described liquid Spredox dispersants are Spredox D-260, D-320, D-159, D-330, D340, D350 or D-141.