KR101908071B1 - Composition and its manufacturing process for high durable transparent conductive coating ink having high optical transmittance, conductivity and mechanical flexibility - Google Patents

Abstract

The present invention relates to a transparent conductive coating liquid, and to a manufacturing method thereof, and specifically, a conductive ink is obtained by mixing: a nanosilver dispersion liquid in which nanosilver particles are dispersed in an organic solvent; an adhesion enhancer; additives such as dispersants; and an aqueous dispersion, and thus the coating liquid has the light transmittance of 87% or more, the conductivity with the sheet resistance of 20~40 Ω/sq and a resistance change rate of 10% or less to have mechanical flexibility.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent conductive coating liquid excellent in light transmittance, conductivity and mechanical flexibility, and a method of manufacturing the transparent conductive coating liquid. 2. Description of the Related Art [0002]

The present invention relates to a nanosilver dispersion in which nanosilver particles are dispersed in an organic solvent; Adhesive strength enhancer; Additives such as dispersants; And a water dispersion to form a conductive ink, thereby obtaining a transparent conductive coating liquid having a light transmittance of 87% or more, a conductivity having a sheet resistance of 20 to 40 Ω / sq and a mechanical flexibility with a resistance change ratio of 10% or less, will be.

 Currently, transparent electrodes, transparent heaters and solar cells for displays such as touch panels, LCDs, and OLEDs, which are the main applications of transparent conductive films (TCF), require conductivity less than 150 Ω / sq and over 80% do.

Carbon nanotube (CNT), nano silver, silver nanowire, and metal mesh have been developed as transparent conductive materials to replace ITO (Indium Tin Oxide). Among alternative materials, it is difficult to find a company that obtains profit by commercializing materials that are superior in terms of optical characteristics, electrical characteristics, and flexibility, but are more cost competitive than ITO.

The CNT material is known to be difficult to commercialize because of its high resistance, poor wet patterning, non-uniformity of conductivity, and high price. Although silver nano wire has realized excellent optical characteristics, it still has no special price competitiveness compared to ITO, There are drawbacks that apply only to some products that require it.

With respect to the transparent conductive film, a large-area film has not yet been developed which maintains a conductivity of 20-40? / Sq and has a light characteristic of 87% or more. Once developed, it can enter other major applications such as touch sensors.

The transparent conductive film is prepared by coating with a conductive coating solution. With respect to conventionally developed conductive coating solutions,

Korean Patent No. 10-1586506 (Registration Date 2016.01.12) discloses a technique for a transparent conductive coating containing a filler material, and Korean Patent Registration No. 10-1043307 (registered on June 15, 2011) ≪ / RTI > coatings and nano-inks, and nano-powder coatings and inks prepared thereby.

However, the techniques disclosed in the related art are excellent in conductivity, but their optical characteristics are deteriorated and their use in a high-quality display touch panel is limited. In addition, metal and organic impurities which are not refined during the production of nanosilver are contained in about 2%, which is a main cause of poor reliability such as deterioration of conductivity after coating.

Korean Registered Patent No. 10-1456838 (Registration date 2014.10.27) Korean Registered Patent No. 10-1333012 (Registration date 2013.11.20) Korean Registered Patent No. 10-1586506 (Registration date 2016.01.12) Korean Registered Patent No. 10-1043307 (Registered on June 15, 2011)

The present invention utilizes nanosilver having a particle size of 10 to 80 nm and a narrow particle distribution to maintain high conductivity and to realize excellent optical characteristics, thereby achieving a light transmittance of 87% or more, a sheet resistance of 20 to 40 Ω / sq And a method for producing the transparent conductive coating liquid, which is capable of securing mechanical flexibility with conductivity and a resistance change ratio of 10% or less, and a method for producing the same.

In order to achieve the above object,

The present invention relates to a nanosilver dispersion liquid comprising 44 to 65 wt% of a nanosilver dispersion liquid prepared by dispersing nanosilver particles in an organic solvent,

0.1 to 5 wt% of an adhesion-enhancing agent for increasing the adhesion of the transparent conductive coating liquid,

0.1 to 5 wt% of an additive for improving dispersion stability and wettability of nano silver,

Wherein the conductive ink is prepared by mixing 34 to 55 wt% of an aqueous dispersion, which is an additive for a siloxane-based water-based paint, and is coated on a plastic film, thereby providing a transparent conductive coating liquid excellent in light transmittance, conductivity and mechanical flexibility.

As a process for producing the transparent conductive coating liquid,

The nanosilver dispersion was prepared by adding the nanosilver particles to an organic solvent and dispersing the nanosilver particles in an amount of 1.5 to 3.5 wt% based on the total weight of the transparent conductive coating liquid, and stirring the mixture at 6,000 rpm to 10,000 rpm for 10 to 40 minutes with a homogenizer. , ≪ / RTI &

44 to 65 wt% of said nanosilver dispersion; 0.1 to 5 wt% of adhesion enhancer; 0.1 to 5 wt% of additive; And the aqueous dispersion is mixed with 34 to 55% by weight of the aqueous dispersion by stirring in a homogenizer at a rate of 6,000 rpm to 10,000 rpm for 20 to 50 minutes to prepare a conductive ink as a coating liquid. A method for manufacturing a transparent conductive coating liquid excellent in mechanical flexibility is provided.

The transparent conductive coating liquid according to the present invention has an excellent stability and optical / electrical properties,

More specifically, by using nanosilver having a particle size of 10 to 80 nm and a narrow particle distribution, it is possible to maintain high conductivity and to realize excellent optical characteristics, so that a light transmittance of 87% or more, a transmittance of 20 to 40 Ω / sq Conductivity with sheet resistance and excellent resistance to change with less than 10% mechanical flexibility.

In addition, the transparent conductive coating liquid prepared according to the process of the present invention has excellent storage stability because it can secure storage stability for 3 months or more so that large-area coating can be performed.

Hereinafter, the technical contents of the present invention will be described in detail.

As described above,

The transparent conductive coating liquid according to the present invention comprises 44 to 65 wt% of a nanosilver dispersion liquid prepared by dispersing nanosilver particles in an organic solvent,

0.1 to 5 wt% of an adhesion-enhancing agent for increasing the adhesion of the transparent conductive coating liquid,

0.1 to 5 wt% of an additive for improving dispersion stability and wettability of nano silver,

Which is an additive for a water-based paint of siloxane series, is mixed with 34 to 55 wt% of an aqueous dispersion,

(EN) Disclosed is a transparent conductive coating liquid excellent in coatability and adhesion to a plastic flexible film such as PET (POLY ETHYLENE TEREPHTHALATE) by using a conductive ink dispersed by adding nano silver particles. At this time, the added amount of the nanosilver particles is 1.5 to 3.5 wt% of the total weight of the transparent conductive coating liquid.

As the substrate which can be coated by the transparent conductive coating liquid thus prepared, all the plastic films are applicable, and in particular, polyethylene terephthalate, polycarbonate, and polymethylmethacrlyate films.

The nanosilver maximizes dispersion stability and optical and electrical properties by nano-silvering to 80 nm or less,

When the added amount of the nanosilver particles is less than 1.5 wt% of the total weight of the transparent conductive coating liquid, the coating liquid according to the present invention hardly satisfies the sheet resistance of 20 to 40 Ω / sq, and when it exceeds 3.5 wt% It is preferable that the transparent conductive coating liquid is used at 1.5 to 3.5 wt% of the total weight in order to satisfy the sheet resistance and the transmittance.

The nanosilver particles have an average particle size of 10 nm to 80 nm. The reason why nanosilver having such a particle size is used is that the surface area is increased by using a small average particle size, thereby using a small amount of nanosilver It is possible to realize excellent sheet resistance.

When the amount of the nanosilver dispersion prepared by dispersing the nanosilver particles in an organic solvent such as toluene is less than 44 wt%, there is a problem of poor conductivity. When the amount of the nanosilver dispersion exceeds 65 wt%, dispersion stability And the cost competitiveness is poor. Therefore, the amount of the nanosilver dispersion is preferably limited within a range of 44 to 65 wt% with respect to the total weight of the transparent conductive coating liquid.

The adhesive strength enhancer is a mixture of a melamine cross-linker and an amine-blocked toluene sulfonic acid,

The melamine cross-linker is hexamethoxymethyl melamine,

The amine-blocked toluene sulfonic acid may be p-toluenesulfonic acid (PTSA), dodecyl benzene sulfonic acid (DDBSA) or dinonylnaphthalene disulfonic acid (dinonyl naphthalene disulfonic acid, DNNDSA).

When the amount of the adhesion-enhancing agent is less than 0.1 wt%, the adhesion of the transparent conductive coating liquid is deteriorated. When the amount of the adhesion-enhancing agent is more than 5 wt%, the dispersion stability and optical properties are deteriorated. Is preferably limited to a range of 0.1 to 5 wt% with respect to the total weight of the transparent conductive coating liquid.

The additive is added to increase the dispersion stability and wettability of the nanosilver, and one or two selected from silicone polyether glycol block polymer or amino-butanol is used.

More specifically, a silicone polyether glycol block polymer and amino-butanol are blended in the same weight ratio and used as an additive.

The silicone polyether glycol block polymer is selected from octamethylcyclotetrasiloxane or decamethylcyclopentasiloxane.

The amino-butanol may be selected from the group consisting of 2-amino-1-butanol, 1-amino-2-butanol, and the like as additives for increasing wettability and light transmittance. butanol, 4-amino-1-butanol, 2-amino-3-methyl-1-butanol, And 2-amino-2-ethyl-1,3-propanediol.

If the amount of the additive used is less than 0.1 wt%, dispersion stability or wettability may deteriorate and coating failure may occur. If the additive is used in an amount exceeding 5 wt%, the viscosity may increase sharply, Is preferably limited to a range of 0.1 to 5 wt% with respect to the total weight of the transparent conductive coating liquid.

The aqueous dispersion is an additive for a siloxane-based water-based paint, more specifically polyether siloxane.

When the amount of the aqueous dispersion is less than 34 wt%, the optical characteristics are deteriorated. When the amount exceeds 55 wt%, the nanosilver is not connected and the conductivity is lowered. Therefore, the amount of the aqueous dispersion used is preferably But is preferably limited to a range of 34 to 55 wt%.

Specific examples of the composition of the transparent conductive coating liquid are shown in Table 1 below.

ingredient Example 1 Example 2 Example 3 Example 4 Example 5 Nano silver dispersion 44wt% 50wt% 55wt% 60wt% 65wt% Adhesion Enhancer * 1.5wt% 1wt% 0.5 wt% 0.3 wt% 0.1 wt% additive** 2.5 wt% 2wt% 1.5wt% 0.7 wt% 0.2 wt% Polyether siloxane 52wt% 47wt% 43wt% 39wt% 34.7 wt% Sum 100wt% 100wt% 100wt% 100wt% 100wt%

The adhesive strength enhancer shown in Table 1 was prepared by mixing hexamethoxymethyl melamine and dinonyl naphthalene disulfonic acid (DNNDSA) at the same weight ratio.

** The additives shown in Table 1 were obtained by mixing decamethylcyclopentasiloxane and 2-amino-3-methyl-1-butanol in the same weight ratio.

The most preferred embodiment among the first to fifth embodiments of Table 1 is the fourth embodiment.

The evaluation results of the physical properties of the transparent conductive film prepared using the transparent conductive coating liquid according to Example 2 are shown in Table 2 below.

Key performance indicators
unit Measures How to measure 1. Transmittance % 88 ASTM D 1003 2. Sheet resistance Ω / sq 35 ASTM D 257 3. Mechanical flexibility (resistance change rate) % 8 ASTM D 257 4. Sea of Japan % 1.9 ASTM D 1003 5. Film Reliability % 9 85/85% RH, 10 days

The transparent conductive coating liquid according to the present invention can be coated on all plastic films, and specific examples thereof include polyethylene terephthalate, polycarbonate, and polymethylmethacrylate.

Next, a method of preparing the transparent conductive coating liquid according to the present invention will be described.

The transparent conductive coating liquid according to the present invention is prepared by adding nanosilver particles to an organic solvent and dispersing the mixture in an amount of 1.5 to 3.5 wt% based on the total weight of the transparent conductive coating liquid. The transparent conductive coating liquid is dispersed in a homogenizer at 6,000 rpm to 10,000 rpm, Lt; / RTI > to prepare a nanosilver dispersion,

44 to 65 wt% of said nanosilver dispersion; 0.1 to 5 wt% of adhesion enhancer; 0.1 to 5 wt% of additive; And 34 to 55 wt% of water dispersion are mixed in a stirrer and stirred with a homogenizer at 6,000 rpm to 10,000 rpm for 20 to 50 minutes to uniformly disperse the mixture to prepare a conductive ink as a coating solution.

More specifically, toluene and nanosilver particles having an average particle size of 10 nm to 80 nm are put into a stirrer and stirred at 8,000 rpm for 20 minutes to prepare a nanosilver dispersion.

60 kg of the thus prepared nanosilver dispersion liquid;

0.3 kg of an adhesion promoter prepared by mixing 0.15 kg of hexamethoxymethyl melamine and 0.15 kg of dinonyl naphthalene disulfonic acid (DNNDSA);

0.7 kg of an additive prepared by mixing 0.35 kg of decamethylcyclopentasiloxane and 0.35 kg of 2-amino-3-methyl-1-butanol;

39 kg of an aqueous dispersion prepared by mixing 0.4 kg of polyethersiloxane with distilled water was placed in a homogenizer and stirred at 9,000 rpm for 30 minutes to prepare a transparent conductive coating solution.

The transparent conductive coating liquid prepared through the above process can be uniformly dispersed for more than 3 months in order to enable large-scale coating, so that it is excellent in storage stability. Therefore, even if it is coated after 3 months, the light transmittance, And has excellent flexibility.

The transparent conductive coating liquid and the manufacturing method according to the present invention are industrially applicable because of ensuring mechanical flexibility with a conductivity of not less than 87% and a sheet resistance of 20 to 40 Ω / sq and a resistance change ratio of less than 10%.

Claims (8)

A transparent conductive coating liquid comprising a nanosilver dispersion and an adhesion-enhancing agent,

The transparent conductive coating liquid is prepared by dispersing 44 to 65 wt% of a nanosilver dispersion in which nanosilver particles are dispersed in an organic solvent,
0.1 to 5 wt% of an adhesion promoter composed of a mixture of a melamine cross-linker and an amine blocked toluene sulfonic acid,
0.1 to 5 wt% of an additive which is one or two selected from silicone polyether glycol block polymer or amino-butanol,
A conductive ink is prepared by mixing 34 to 55 wt% of an aqueous dispersion prepared by mixing polyethersiloxane and distilled water as an additive for a water-based siloxane paint, and coating the film on a plastic film. Transparent conductive coating fluid with excellent mechanical flexibility.
The method according to claim 1,
Wherein the nanosilver particles are added in an amount of 1.5 to 3.5% by weight based on the total weight of the transparent conductive coating liquid, and the nanosilver particles are excellent in light transmittance, conductivity and mechanical flexibility.
The method according to claim 1 or 2,
Wherein the nanosilver particles have an average particle size of 10 nm to 80 nm. The transparent conductive coating liquid is excellent in light transmittance, conductivity, and mechanical flexibility.
The method according to claim 1,
The adhesive strength enhancer may be a melamine cross-linker of hexamethoxymethyl melamine;
Which is at least one selected from the group consisting of p-toluenesulfonic acid (PTSA), dodecyl benzene sulfonic acid (DDBSA), and dinonyl naphthalene disulfonic acid (DNNDSA) (Amine blocked toluene sulfonic acid), which is excellent in light transmittance, conductivity, and mechanical flexibility.
The method according to claim 1,
The additive may be a silicone polyether glycol block polymer of octamethylcyclotetrasiloxane or decamethylcyclopentasiloxane; or
Amino-1-butanol, 1-amino-2-butanol, 4-amino-1-butanol, 2-amino-3-methyl-1-butanol or 2-amino-2-ethyl- 1,3-propanediol); amino-butanol; And the transparent conductive coating liquid is excellent in light transmittance, conductivity, and mechanical flexibility.
delete delete The nanosilver dispersion was prepared by adding the nanosilver particles to an organic solvent and dispersing the nanosilver particles in an amount of 1.5 to 3.5 wt% based on the total weight of the transparent conductive coating liquid, and stirring the mixture at 6,000 rpm to 10,000 rpm for 10 to 40 minutes with a homogenizer. , ≪ / RTI &
44 to 65 wt% of said nanosilver dispersion; 0.1 to 5 wt% of an adhesive strength enhancer formed by mixing a melamine cross-linker and an amine blocked toluene sulfonic acid; 0.1 to 5 wt% of an additive which is one or two selected from silicone polyether glycol block polymer or amino-butanol; As an additive for a siloxane-based water-based paint, 34 to 55 wt% of an aqueous dispersion prepared by mixing polyethersiloxane and distilled water was stirred in a homogenizer at 6,000 rpm to 10,000 rpm for 20 to 50 minutes, Wherein the conductive ink is a coating liquid. The method of manufacturing a transparent conductive coating liquid according to claim 1, wherein the conductive ink is a coating liquid.