JPH10258486A - Manufacture of transparent conductive resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain high transparency and improve conductivity by printing or applying ink composition containing indium tin oxide on the transparent resin film before being treated by a calender. SOLUTION: A base material polyester(PET) film is delivered from a rolling out device 1, and ink 3 having indium tin oxide(ITO) powder mixed in resin is transferred on one surface of a transparent resin film 10 such as PET of the base material via an intaglio gravure roller 2. In this instance, excessive ink is scraped off by a doctor blade 4. After that, a PET film 10 is forwarded by a roller 6 to subsequently be dried by a dryer 7; then being in close contact with a calender roller 8 for giving a calender treatment. Following this, it is wound up by a winding up roller 9. ITO-containing ink 3 is prepared in low viscosity to be suited for gravure printing. Thus, a thickness of the conductive layer becomes thinner, and a transparency of the film becomes more excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of transparent electrodes and antistatic films widely used for electronic members such as displays, the field of transparent film packaging materials for ICs having an electrostatic shielding function, and windows for the purpose of improving cooling and heating efficiency. The present invention relates to a method for producing a transparent conductive resin film in the field of infrared shielding materials and the like which are used by being adhered to a film or the like.

[0002]

2. Description of the Related Art Conventionally, as a transparent conductive resin film, a resin film such as polyester (PET) is used on a resin film.
O (Indium Tin Oxide)
O "), which is physically deposited by means of vacuum deposition, sputtering, ion plating or the like.
Films are used, but these methods require expensive equipment, have low productivity, and are not suitable for obtaining wide films at low cost. As a method for printing or applying the ink composition containing fine ITO powder on a resin film, there are known methods such as screen printing, gravure printing, bar coater coating, and roll coater coating. The obtained transparent conductive film had a problem that the thickness of the conductive layer was 1 μm or more, and the transparency of the obtained conductive layer was reduced.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a transparent conductive resin film having high transparency and improved conductivity.

[0004]

Means for Solving the Problems The present inventor has achieved that the above object can be achieved by forming a thin layer of an ink composition containing ITO on a transparent resin film and subjecting it to a calender treatment. Have found the present invention. That is,
The method for producing a transparent conductive film of the present invention is characterized in that: (1) an ink composition containing ITO is printed or applied on a transparent resin film, and then calendered. (2) In the production method described in the above (1), the transparent resin film of the above (1) is a polyester resin (PE)
T).

[0005]

The transparent resin film of the present invention has higher transparency and higher conductivity than those of the conventional method, unlike the film obtained by the conventional method. According to the production method of the present invention,
A transparent electrode, a circuit, and the like having a specific pattern can be formed at a time by a continuous, high-speed gravure printing method without a post-process such as etching.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a manufacturing apparatus according to one embodiment of the present invention. The PET film of the base material is supplied from the unwinding device 1 and the transparent resin film 10 of the base material such as polyester (PET) through the intaglio gravure roll 2.
Is transferred to one side of the ink. At that time, the extra ink is
Is scraped off by Thereafter, the PET film is fed by a roll 6, dried by a dryer 7, calendered by being compacted by a calender roll 8, and then wound by a winding device 9.

[0007] The ITO-containing ink 3 in the present invention is a commercially available ITO ink, but is adjusted to have a low viscosity so as to be suitable for gravure printing. The composition of the ITO-containing ink used in the present invention is as follows:-ITO fine powder; 10 to 30 wt%-Binder resin; 1 to 6 〃-Solvent, etc.; , Polyester resin, etc. are used,
When applied on a transparent resin film such as ET, a polyester resin is recommended from the viewpoint of adhesion to the film. The diluting solvent for adjusting the viscosity is not particularly limited, but a general diluting solvent used in gravure printing, such as toluene, xylene, methyl ethyl ketone, or cyclohexanone, can be used. The appropriate viscosity range of the ITO-containing ink used in the present invention is 10 to 500 centipoise (25
℃), but if the viscosity of the ink is too high, the transfer rate of the ink to the transparent film of the base material is deteriorated, so that the viscosity as low as possible is easier to use. In addition, ITO in the ink
In order to increase the dispersion stability of the fine powder, a dispersant such as a surfactant or an additive added for other purposes may be included.

Next, the gravure printing machine used in the present invention may be of an ordinary grade, but it is of course better to use a high-precision machine and a plate-making roll when performing pattern formation. is there. The gravure printing method can perform high-speed printing, but the printing speed is easily limited by a drying step, and when printing on a transparent conductive polyester resin film, the printing is performed at about 10 to 60 m / min. Nevertheless, printing can be performed at a speed one order faster than the conventional screen printing method. As a condition of the dryer, hot air drying can be suitably used. Normally, drying temperature 80 ° C ~ 12
At 0, the drying time may be about 0.1 to 3 minutes. Insufficient drying not only increases the surface resistance of the obtained film, but also causes roll contamination on the next calender roll 8, so that the film must be sufficiently dried. Therefore, a gravure coater having a long drying zone is more suitable as a gravure printing machine than a high-speed machine widely used in the printing industry.

For the calendering treatment, the following hot roll conditions are preferred.・ Applied load (linear pressure): 20 to 400 kg / cm ・ Temperature: 80 to 130 ° C. ・ Speed: 0.5 to 60 m / min In the present embodiment shown in FIG. Although it is being carried out, a film in which a conductive layer of a desired pattern is printed in advance on a base film by a separate gravure printing machine with an ITO-containing ink,
Calendar processing may be performed in another step. A calender roll having a stainless steel on the heating roll side and a heat-resistant resin lining on the opposing roll (backup roll) side can be suitably used. By performing this calendering process, the film thickness of the conductive layer becomes thinner, the transparency of the film is further improved, and not only the haze of the film is remarkably improved, but also the surface resistance becomes 1/3 to 1/10. To decline. The reason for this is that when the conductive layer is formed, there are many internal pores due to rapid drying, and it is a porous ITO layer,
This is considered to be due to the fact that it is compacted by calendering to improve transparency and electric conductivity. As for the drying speed, the lower the drying speed, the better the transparency of the film and the lower the surface resistance, but this is not efficient in the manufacturing process. In that respect, even if high-speed drying is performed after printing, by performing a calendering process after printing as in the present invention, it is possible to obtain a material having a performance comparable to that of natural drying at room temperature. It can be said that. In addition, the formation of the conductive layer with the ITO-containing ink composition on the base film may be performed by solid printing on the entire surface in addition to the printing of the specific pattern, or by using a coater on the entire surface of the base film. It may be applied, coated, dried and calendered by a calender roll.

(Example) Each of the following raw materials (1) was kneaded to prepare an ITO-containing ink composition having a viscosity at 25 ° C of 80 centipoise. (1) ITO ink composition ・ ITO = 17 Wt% ・ Binder (polyester resin) = 3% ・ Solvent (main component of cyclohexanone) = 80% Next, gravure is applied to a transparent PET resin film substrate by the process illustrated in FIG. IT of specified pattern by printing
A conductive film made of the O-containing ink composition was formed. Gravure printing conditions were as follows (2) and (3). (2) Gravure printing ・ Intaglio printing depth 30 μm (solid printing) ・ Effective printing width 1050 mm ・ Printing speed 40 m / Min (3) Dryer ・ Drying temperature (hot air drying type) ・ ・ ・ 100 ℃ ・ Effective PIC ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 20m ・ Drying speed ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 40m / min Then The transparent conductive film on which the conductive film made of the ITO-containing ink composition was formed was calendered under the following condition (4) to obtain a transparent conductive resin film of Example. (4) Calendering conditions ・ Applied load (linear pressure): 200 kg / cm ・ Heat roll surface temperature: 80 ° C. ・ Speed: 40 m / min

Comparative Example A transparent conductive resin film of a comparative example was obtained in the same manner as the film of the example except that the calendering treatment of (4) was not performed. The film thickness of the formed ITO layer, the haze of the entire film, the total light transmittance, the total light transmittance, the parallel light transmittance, and the surface resistance of the film were measured for each of the films thus obtained in Examples and Comparative Examples. The values are shown in Table 1 together with the values of only the transparent PET resin film substrate used at this time.

[0012]

[Table 1]

As can be seen from Table 1, the film of the embodiment according to the present invention is simply compared with the film of the comparative example in which an ITO film is formed by a gravure printing method, and further subjected to a calender roll treatment. The haze was lower, the light transmittance was higher, and the surface resistance was significantly reduced. Although the gravure printing method has been described in the present embodiment, it goes without saying that the calendar processing effect can be similarly recognized in other printing methods and coating methods.

[0014]

As described above, according to the present invention,
A film having a smaller film thickness and higher transparency (higher light transmittance) than a transparent conductive film formed by printing or coating using a conventional ITO ink composition can be obtained. Further, as compared with the conventional vapor deposition method, patterning can be performed at one time, and the manufacturing process can be simplified, so that the film can be manufactured at lower cost. The utility value is extremely large.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a manufacturing apparatus used in one embodiment of the present invention.

[Description of Signs] 1... Unwinding device 2... Gravure roll 3... Ink pan (ITO ink) 4... Doctor blade 5... Backup roll 6. 7 ... Dryer 8 ... Calendar roll 9 ... Winding device 10 ... PET film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09D 11/02 C09D 11/02

Claims (2)

[Claims] 1. An ITO (Indi) film is placed on a transparent resin film.
A method for producing a transparent conductive resin film, comprising printing or applying an ink composition containing um Tin Ox-ide) to form a conductive layer, and then subjecting the conductive layer to a calendar treatment. 2. The method for producing a transparent conductive resin film according to claim 1, wherein said transparent resin film is a polyester resin (PET).