KR20150118449A - Photo-curable composition of UV protecting and antioxidation UV-curing over coating solution for transparent conductive film - Google Patents

Abstract

According to the present invention, a photocurable coating composition for overcoating a transparent electrode film comprises: an organic-inorganic hybrid sol-gel compound; and a urethane acrylate oligomer or an acrylate monomer, wherein the organic-inorganic hybrid sol-gel compound is in a state of one species selected from silica, titanium oxide, alumina, magnesium oxide, and zirconium oxide, or a sol or a gel or more. When being additionally overcoated on a conductive film layer of the transparent electrode film using the photocurable coating composition, the composition represents significant effects in improving environmental resistance of ultraviolet rays and air, while maintaining fundamental electrical and physical properties.

Description

[0001] The present invention relates to a photo-curable composition for a transparent electrode film overcoat having a UV blocking and antioxidant function,

The present invention relates to a photo-curable coating composition for the purpose of blocking ultraviolet rays and forming an anti-oxidation protective film of a transparent electrode film. More particularly, the present invention relates to a UV- To provide a curable overcoating composition.

The transparent electrode film is a thin film electrode that imparts conductivity while maintaining transparency on the surface of an insulating material made of a transparent material of glass and a plastic substrate. Applications thereof include a liquid crystal display (LCD), a plasma panel display (PDP), an organic light emitting diode ), And other display fields, it is used in a wide range of fields such as touch panel, smart window, transparent electromagnetic wave shielding film, transparent heat emitting body, conductive glass, gas sensor, heat reflection coating film and solar battery. In particular, transparent electrode films are not only electrodes for touch panels for flexible devices, but also are key components for information and electronic energy fields that can be applied to transparent antistatic films, antennas for communication devices, and optical filters depending on the sheet resistance.

Indium Tin Oxide (ITO) materials have been widely used as transparent electrode core materials in various electronic devices such as LCD panels, PDP panels, touch panels, electronic paper, solar cells, and OLED panels. However, ITO (indium tin oxide), a transparent electrode film that is exposed to various display materials, requires high-priced equipment because it is a deposition process that must be physically coated at high temperature and high pressure. Due to the resource depletion of main raw material indium, In the case of an ITO (indium tin oxide) film of a plastic substrate, due to the nature of indium oxide, it tends to be broken even by a small external impact or stress, and mechanical stability is poor when the film is bent or folded. There is a problem that electrical characteristics are changed due to thermal deformation. Furthermore, there are various problems in the use of conventional ITO transparent electrodes in transparent electrodes requiring large area and bending flexibility. The biggest problem of the ITO film is that it has a resistance limit which is a core function of the electrode, so that it is still difficult to manufacture a transparent electrode having a basic property of less than about 100? / Sq.

For this reason, in recent years, there has been an active trend to introduce a new transparent electrode material in place of the existing ITO.

As a material of the transparent electrode film that can replace the ITO film, metal is generally used, and copper, silver, nickel, hybrids thereof, or the like are used. These metal materials may be mesh networks, And the like. Metal materials are used in the form of nanostructures and fine dispersions. In the film coating method of the nanostructured metal (silver, copper, nickel, etc.), the transparent electrode film of the metal material is oxidized by ultraviolet rays to cause oxidation of the metal electrode, The basic performance of the electrode is lost. In addition, since the hardness of the metal conductive electrode film is low and it is easily reacted with a compound of another material, there is a problem that it is vulnerable to environmental resistance. Further, there is a problem that the metal is oxidized due to oxygen or moisture in the air due to long-term storage, thereby deteriorating electrical characteristics.

An object of the present invention is to provide a photocurable coating composition having an ultraviolet blocking function, an antioxidation function and a bending property without changing the general electrical and physical properties by a roll to roll process, .

The photocurable coating composition for achieving the above object is prepared by an overcoating process on a cross section of a transparent electrode, and has a function of blocking ultraviolet rays and preventing oxidation. In addition, the photocurable coating composition is basically made to satisfy transparency, hardness, Curable type, i. E., A photocurable coating composition for overcoating.

Gel compound and a urethane acrylate oligomer or an acrylate monomer, wherein the organic-inorganic hybrid sol-gel compound is one or more selected from the group consisting of silica, titanium oxide, alumina, magnesium oxide, and zirconium oxide, It is preferable to provide a photocurable coating composition characterized in that it is further in a sol or gel state.

According to a preferred feature of the present invention, the photocurable coating composition preferably comprises a UV stabilizer or an antioxidant.

According to a further preferred feature of the present invention, the ultraviolet stabilizer is selected from the group consisting of benzophenone, benzotriazole, phenol, hindered amine light stabilizer (HALS) and phosphite, Or one or more selected from the group consisting of

According to a further preferred feature of the present invention, the antioxidant is preferably one or more selected from the group consisting of phenol, amine, phosphite and thiosteres.

According to a further preferred feature of the present invention, the urethane acrylate oligomer is preferably an aliphatic urethane acrylate oligomer having 3 to 15 functional groups.

According to a further preferred feature of the present invention, the acrylate monomer is preferably at least one selected from the group consisting of epoxy acrylate, ester acrylate, silicone acrylate and alkyl acrylate.

According to an even more preferred feature of the present invention, the photocurable composition comprises 1 to 6% by weight of the organic-inorganic hybrid sol-gel compound and 1 to 6% by weight of the urethane acrylate oligomer or acrylate monomer, based on the total weight of the composition .

According to a further preferred feature of the present invention, it is preferable that the photocurable composition further comprises 90 to 95% by weight of a solvent, 0.1 to 1% by weight of a photocuring agent, and 0.1 to 1% by weight of an additive with respect to the total weight of the composition .

According to a further preferred feature of the present invention, the solvent is preferably at least one selected from the group consisting of an alcohol-based, amine-based and ketone-based solvent.

According to a further preferred feature of the present invention, the photocuring agent is selected from the group consisting of ketone, phosphine, benzophenone, sulfide, and phosphine oxide Or more.

According to a further preferred feature of the present invention, it is preferable that the additive is at least one selected from the group consisting of a surfactant, a leveling agent, a wetting agent, a slip agent and a heat stabilizer.

The photocurable coating composition according to the present invention is used as an overcoating agent on a conductive section of a transparent electrode to form an ultraviolet screening and an anti-oxidation protective film, and other general electrical and physical properties, And exhibits an excellent effect in improving the stability.

FIG. 1 (a) is a SEM image showing particles of an organic-inorganic hybrid sol-gel used as an example, (b) shows a surface of a transparent electrode coated with a photocurable coating composition prepared in Example 1 SEM image shown.
2 (a) is an SEM image (after 100 hours of the QUV tester) showing the surface of the transparent electrode to which the ultraviolet stabilizer prepared in Example 5 is added, (b) SEM image showing the surface of the transparent electrode after 500 hours in the tester.

Hereinafter, preferred embodiments of the present invention and physical properties of the respective components will be described in detail with reference to the accompanying drawings. However, the present invention is not limited thereto, And this does not mean that the technical idea and scope of the present invention are limited.

The photocurable coating composition according to the present invention can be applied to a wide variety of substrates including organic-inorganic hybrid sol-gel compounds; And a urethane acrylate oligomer or an acrylate monomer, wherein the organic-inorganic hybrid sol-gel compound is at least one sol or gel state selected from silica, titanium oxide, alumina, magnesium oxide and zirconium oxide.

The above-described organic-inorganic hybrid sol-gel compound preferably contains 1 to 6% by weight based on the total weight of the composition. When the amount is less than 1% by weight, formation of a coating film capable of protecting the electrode layer And when it is more than 6% by weight, the hardness is increased but the function as a transparent electrode is lost due to overprotection of the electrode layer. More specifically, the above-mentioned organic-inorganic hybrid sol-gel compound is chemically very stable, and has excellent characteristics such as corrosion resistance and abrasion resistance. When used singly, a coating film having high hardness is not formed. Or an acrylate monomer.

The above-mentioned urethane acrylate oligomer preferably contains 1 to 6% by weight based on the total weight of the composition. When used in combination with the above-described organic-inorganic hybrid sol-gel compound, the urethane acrylate oligomer has a role of forming a high- do.

More specifically, the urethane acrylate oligomer described above is preferably an aliphatic urethane acrylate oligomer having 3 to 15 functional groups. When the functional group of the oligomer is less than 3, there is a problem that the hardness is lowered. As the functional group is increased This is because the formation of a coating film by a multi-functional group is robust and it is a cause of hindering the electrical characteristics. The above-mentioned acrylate monomers are preferably at least one selected from the group consisting of epoxy acrylates, ester acrylates, silicone acrylates and alkyl acrylates, more preferably alkyl acrylates.

The photocurable coating composition according to the present invention preferably contains 0.01 to 5% by weight of an ultraviolet stabilizer or an antioxidant based on the total weight of the composition. If it is less than 0.01% by weight, the effect on UV stability or oxidation stability is insufficient , And when it exceeds 5% by weight, the composition is not cured.

More specifically, the ultraviolet light stabilizer absorbs ultraviolet light and emits ultraviolet light in the form of heat to stabilize the polymer. The ultraviolet light stabilizer may be a benzophenone-based, a benzotriazole-based, a phenol- HALS, hindered amine light stabilizer and phosphite, and more preferably one or more selected from the group consisting of benzophenone and benzotriazole. Specific examples thereof include 2,4-dihydroxybenzophenone and 2- (2'-hydroxyphenyl-benzotriazole).

The antioxidant mentioned above is preferably one or more selected from the group consisting of phenol-based, amine-based, phosphite-based, and sulfide-based ones and specifically includes Butylated hydroxyl toluene, Pentaerythrityl-tetrakis [3- (3,5- -butyl-4-hydroxy phenyl) -propionate], and Tris (nonylphenyl) phosphite.

In addition, the photocurable coating composition according to the present invention preferably further comprises 90 to 95% by weight of a solvent, 0.1 to 1% by weight of a photocuring agent, and 0.1 to 1% by weight of an additive, based on the total weight of the composition.

More specifically, the above-mentioned solvent is preferably at least one selected from the group consisting of alcohol, amine and ketone, but is not limited thereto. The photocuring agent described above functions to bond the binding of the composition, and specifically includes a ketone-based, phosphine-based, benzophene-based, sulfide-based, and phosphineoxide- And the like.

If the amount of the additive is less than 0.1% by weight, the wet film may not be formed. If the amount of the additive is more than 1% by weight, the curing may not be completely performed. The above-mentioned additives are preferably at least one selected from a surfactant, a leveling agent, a wetting agent, a slip agent, and a heat stabilizer, but are not limited thereto. Specifically, the above-mentioned surfactants may be silicon, epoxy, modified silicone, acrylic, ether, fluorine, and the like. The leveling agent may be a sulfonic acid type or a silicone type. As the wetting agent, a silicone system, a fluorine system, or the like can be used. The above-mentioned heat stabilizer may be a Cd / Ba / Zn system, a Cd / Ba system, a Ba / Zn system, a Ca / Zn system, a Na / Za-based, Sn-based, Pb-based, Cd-based, Zn-based and the like.

The photocurable coating composition according to the present invention can be used not only as a protective film for a transparent electrode but also as an electrode layer for a solar cell, a touch panel, a transparent electromagnetic shielding film , Transparent heating elements, conductive glass, gas sensors, lighting, and automobiles.

Hereinafter, the photocurable coating composition according to the present invention will be described by way of examples.

≪ Examples 1 to 4 >

The photo-curable coating composition was prepared by adding silica sol, urethane acrylate oligomer or acrylate monomer, a solvent and an additive thereto and stirring at 500 rpm for 5 minutes using a stirrer (TOKYO RIKAKKAI, NZ-1100). (The content of each component is shown in Table 1 below).

≪ Example 5 >

The same procedures as in Examples 1 to 4 were carried out except that an ultraviolet stabilizer was added.

≪ Example 6 >

An antioxidant was added in the same manner as in Examples 1 to 4 described above.

≪ Comparative Examples 1 and 2 &

The same procedures as in Examples 1 to 4 were carried out except that a urethane acrylate oligomer or an alkyl acrylate monomer, a solvent and an additive were added. (The content of each component is shown in Table 1 below).

Component (% by weight) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Silica sol 5 5 2 2 5 5 - - Urethane acrylate oligomer 2 - 5 - 2 2 - - Alkyl acrylate monomers - 2 - 5 - - 7 - Epoxy acrylate oligomer - - - - - - - 7 Alcoholic solvent 32 32 32 32 32 32 32 32 Amine-based solvent 30 30 30 30 30 30 30 30 Ketone solvent 30 30 30 30 30 30 30 30 Light curing agent 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Silicone surfactant 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 (2'-Hydroxy-3 ', 5'-di-t-amylphenyl) benzotriazole, - - - - 0.5 - - - Tris (nonylphenyl) phosphite - - - - - 0.5 - -

In each of the test examples, evaluation items of the physical properties and measurement methods thereof are as follows.

(1) Light transmittance (%) and turbidity: Nippon Denshoku Indusries Co. LTD, NDH-5000 at room temperature.

(2) Electrical Conductivity (ohm / sq): 4 point-probe method was used. The transparent conductive film was divided into 9 equal parts and each sheet resistance was measured using Mitsubishi Chemical Corporation, Loresta-GP and MCP-T600 The mean value was calculated.

(3) Environmental resistance test: The sheet resistance value after 0 hours and 240 hours at a temperature of 85 占 폚 and a humidity of 85% was measured, and the amount of change (?) Was measured.

(4) Hardness: The test was carried out using a pencil of each type 6B to 2H using a tester complying with a pencil scratch tester for coating film (JIS-K-5401), and the film surface of the test sample after the test was visually observed Respectively.

(5) UV stability: For the test for UV stability, the sheet resistance value was measured after 240 hours at a temperature of 50 캜 and a light intensity of 0.5 W / m ² using Q-LAB CORPORATION, QUV / SE, ) Were measured.

<Test Example>

Bar coating was performed by applying a metal nanowire composition on a substrate, and the photocurable coating composition prepared in Examples 1 to 6 and Comparative Examples 1 and 2 was coated thereon to perform bar coating, The transparent electrode was prepared by photocuring drying using a UV curing machine. Physical properties of the transparent electrode thus prepared were measured, and the results are shown in Table 2.

In addition, Comparative Example 3, in which a photo-curable coating composition was not coated with a transparent electrode, was prepared and its physical properties were measured.

(The substrate was polyethylene terephthalate (PET) film, Toray Advanced Material Co., U43R), and an index matching coating was applied to the film to obtain a substrate having a transmittance of 92.5%.

In the metal nanowire composition, a solution consisting of 86.5 g of purified water, 0.5 g of hydroxypropylmethylcellulose, 12 g of a silver nanowire 0.5% dispersion and 1 g of a fluorinated surfactant was used.

Evaluation items
Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Light transmittance (%) 91.12 91.04 90.89 90.88 91.10 91.92 90.85 90.77 90.62 Turbidity 1.09 1.13 1.19 1.22 1.11 1.12 1.21 1.24 1.32 Environmental tolerance T = 0 (? / Sq) 84.5 85.6 87.2 87.8 85.3 86.5 88.1 88.3 83.4 T = 240 hrs
(Ω / sq) 89.8 93.2 96.8 97.9 90.8 91.7 102.3 108.7 > 10 ¹² Change amount (%) 6.27 8.88 11.01 11.5 6.45 6.01 16.12 23.1 - UV stability T = 0 (? / Sq) 84.5 85.6 87.2 87.8 85.3 86.5 88.1 88.3 83.4 T = 240 hrs
(Ω / sq) 501.4 495.7 545.1 602.5 108.5 111.1 659.5 680.2 > 10 ¹² Change amount (%) 493.4 479.1 525.1 586.2 27.2 28.4 648.6 670.3 - Hardness 2H 2H 1H 1H 2H 2H B B 6B

As shown in Table 2, the transparent electrode coated with the photocurable coating composition prepared in Examples 1 to 6 as compared with Comparative Examples 1 to 3 exhibited improved light transmittance and turbidity, less change amount (?) Of the sheet resistance value It was confirmed that it was also effective in environmental resistance. In Comparative Example 3 in which the above-mentioned photocurable coating composition was not coated, the light transmittance and turbidity were improved, but the hardness was remarkably lowered, which is not preferable.

In addition, the transparent electrode including the ultraviolet stabilizer prepared in Example 5 has superior ultraviolet stability compared to the other examples and the comparative example.

Therefore, the photocurable coating composition according to the present invention is used as an overcoating agent on the conductive cross section of the transparent electrode to form an ultraviolet blocking and anti-oxidation protective film, and other general electrical and physical properties, And exhibits excellent effects in improving the resistance to chemicals.

Claims (12)

Organic-inorganic hybrid sol-gel compound; And
A urethane acrylate oligomer or an acrylate monomer,
Wherein the organic-inorganic hybrid sol-gel compound is one or more sol or gel state selected from silica, titanium oxide, alumina, magnesium oxide and zirconium oxide.
The method according to claim 1,
Wherein said photocurable coating composition comprises an ultraviolet light stabilizer or an antioxidant.
3. The method of claim 2,
The ultraviolet stabilizer may be at least one selected from the group consisting of Benzophenone, Benzotriazole, Phenol, HALS, and Phosphite. &Lt; / RTI &gt;
The method according to claim 2, wherein
Wherein the antioxidant is one or more selected from the group consisting of phenol, amine, phosphite and thioester.
The method according to claim 1,
Wherein the urethane acrylate oligomer is an aliphatic urethane acrylate oligomer having 3 to 15 functional groups.
The method according to claim 1,
Wherein the acrylate monomer is at least one selected from the group consisting of epoxy acrylate, ester acrylate, silicone acrylate and alkyl acrylate.
The method according to claim 1,
Wherein said photocurable coating composition comprises, relative to the total weight of said composition, 1 to 6% by weight of an organic-inorganic hybrid sol-gel compound and 1 to 6% by weight of a urethane acrylate oligomer or acrylate monomer. Composition.
The method according to claim 1,
Wherein said photocurable coating composition further comprises 90 to 95% by weight of solvent, 0.1 to 1% by weight of photo-curing agent, and 0.1 to 1% by weight of additive, based on the total weight of said composition.
9. The method of claim 8,
Wherein the solvent is one or more selected from the group consisting of an alcohol, an amine and a ketone.
9. The method of claim 8,
Wherein the photocuring agent is one or more selected from the group consisting of ketone, phosphine, benzophenone, sulfide, and phosphine oxide. Coating composition.
9. The method of claim 8,
Wherein the additive is one or more selected from the group consisting of a surfactant, a leveling agent, a wetting agent, a slip agent, and a heat stabilizer.
11. A transparent electrode comprising an overcoat layer comprising the photo-curable coating composition of any one of claims 1 to 11.

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