KR20050042626A - Hard coating method of transparent film for use display panel and apparatus for the same - Google Patents

Abstract

The present invention relates to a method for hard coating a transparent film for display, wherein the die while transferring any one of the die or the flat plate of the die coating means in a state in which the display transparent film to be a hard coating object horizontally fixed on the flat plate Hard coating of the transparent film for display using a coating means, comprising the step of applying a hard coating liquid to the surface of the transparent film for display, the hard coating liquid coating layer, and curing the coating layer The method is disclosed.

According to the present invention, a hard coating film having a uniform thickness may be formed on the display transparent film, and both surfaces of the transparent film may be coated independently, and the loss of the hard coating liquid may be reduced.

Description

Hard coating method of transparent film for display and apparatus therefor {Hard coating method of transparent film for use display panel and apparatus for the same}

The present invention relates to a hard coating method and a device of the transparent film for display, and more particularly, the thickness of the coating liquid can be uniformly formed throughout the transparent film for display, and also different coatings on both sides of the transparent film The present invention relates to a hard coating method of a transparent film for display and a device thereof, which can impart characteristics and reduce loss of coating solution.

Display panels are widely used in display devices such as TVs, electronic calculators, electronic clocks, car navigation systems, office automation equipment, mobile phones, and notebook computers because of their thinness.

Such display panels may be classified into various types according to the operation principle thereof. For example, a common process in manufacturing processes of most display panels including a liquid crystal display (LCD) may include various materials or electrodes for pixel configuration. And the like are formed on a glass substrate.

However, a display panel employing a glass substrate has a disadvantage in that it is easily broken due to the inherent characteristics of glass having a low impact resistance, and it is a fact that the weight per unit volume is large, making it difficult to reduce the weight.

As an alternative, in recent years, attempts have been made to replace glass substrates with a panel made of a plastic transparent film having excellent impact resistance and light weight, or to configure an external protective window, a touch panel, etc. of a mobile phone. As the transparent film for the display panel, polycarbonate (PC), polyethersulfone (PES), polymethylmethacrylate (PMMA), etc., which are relatively superior to other materials, are widely used. .

The plastic transparent film as described above has a disadvantage that it is very vulnerable to scratches. To compensate for this, a hard coat film is generally formed on the surface of the plastic transparent film.

On the other hand, a thin plastic film is widely used for various display panels such as an external protective window or a touch panel of a mobile phone. When the thin plastic film is rolled and subjected to a hard coating process, curling is very severe. There is a disadvantage that occurs in the hard coating layer during the winding (Winding) process, it is common to proceed the hard coating process in the sheet-like sheet state.

Coating methods conventionally used for hard coating on a plate-shaped display plastic transparent film include a flow coating method and a dip coating method. Here, the coating method is a flow coating method by spraying the hard coating liquid from the upper portion in the fixed state standing up vertically to flow down to the bottom, the dip coating method is a hard coating liquid in a vertical state of the transparent film The coating process is carried out by dipping into the container.

However, in the case of the flow coating method, there is a problem in that the thickness of the coating film is gradually increased toward the lower portion of the film, and the dip coating method also has a problem in that a thickness variation for each part of the film is greatly generated.

In addition, the conventional hard coating methods as described above not only have a large loss of coating solution, but also have to apply the same hard coating solution and coating thickness to both sides of the film, thereby providing a transparent film for display having different coating properties on both sides of the film. There is a limit that cannot be obtained.

The present invention has been made to solve the above problems, the hard coating process can be carried out in a state in which the transparent film is mounted horizontally to obtain a coating film having a uniform thickness for each part of the transparent film for display, transparent Hard coating method of the transparent film for display that can give different coating properties to both sides of the film, and can selectively reduce the loss of hard coating liquid by selectively supplying only the hard coating liquid corresponding to the area of the transparent film to be coated and The purpose is to provide the device.

In order to achieve the above object, the hard coating method of the transparent film for a display according to the present invention is a die of the die coating means or any one of the flat plate in a state in which the transparent film for display, which is a hard coating object, is fixed horizontally on a flat plate. A first step of applying a hard coating liquid to the surface of the transparent film for display using the die coating means while transferring one; A second step of drying the hard coating solution coating layer; And a third step of curing the coating layer.

Preferably, the hard coating solution may include an acrylate monomer, a solvent and a curing agent.

The viscosity of the hard coating solution is preferably in the range of 10 ~ 10000cps.

Before the first step, the step of removing the foreign matter by passing the transparent film for display through an adhesive roller may be additionally performed.

The thickness of the transparent film for display is preferably in the range of 500 ~ 1500㎛.

According to another aspect of the present invention, a flat plate for horizontally placing a transparent film for display, which is a hard coating object, and fixing means for fixing the transparent film on a flat plate, and hard on the surface of the transparent film through a predetermined die. Die coating means for applying a coating liquid, a transfer unit for transferring any one of the die or flat plate so that the hard coating liquid coating treatment is continuously performed along the longitudinal direction of the transparent film for display, and a hard coating liquid formed on the transparent film for display Provided is a hard coating apparatus for a transparent film for a display including a dry hardener for drying and curing an application layer.

The fixing means may be configured to fix the transparent film for display on the flat plate by the vacuum suction method.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is a flowchart illustrating a process of performing a transparent film hard coating method for a display according to a preferred embodiment of the present invention.

As shown in FIG. 1, the present invention is to perform a hard coating process by a die coating method in a state in which the plastic transparent film for display is horizontally disposed, and as shown in steps S100 to S120, the setting and transparentness of the die coating means. The process of mounting the film is preceded.

Specifically, the setting process of the die coating means (step S100) accommodates the hard coating liquid in a predetermined container of the die coating means and transfers a die having a width corresponding to the plastic transparent film to be coated. This is achieved by enabling configuration.

Here, the plastic transparent film is, for example, dried polycarbonate polymer resin in a chip state, and then melted using a predetermined extruder, and through a T-die (Die), for example, in the form of a sheet having a thickness and an appropriate width of 500 ~ 1500㎛. It can be formed by extrusion. More preferably, the thickness of the plastic transparent film is in the range of 500 ~ 1000㎛ when considering the thickness that can be mounted thin without lowering the light transmittance for various display-related products, such as an external protective window or touch panel of a mobile phone It can be formed as.

As the polymer resin used as the material of the plastic transparent film, an acrylic resin such as polymethyl methacrylate, a polyether sulfone resin, a polyarylate, a cycloolefin copolymer, or the like may be used.

The transparent film is preferably subjected to a separate foreign matter removing step of passing through a predetermined adhesive roll rotatably installed in a structure having an adhesive on the surface (step S110). In addition, as a pretreatment process for increasing the adhesion of the coating liquid, a process of plasma or corona treatment of the surface of the transparent film may be further performed.

The transparent film corresponding to the coating object is mounted in such a manner as to be fixed to the flat plate while being horizontally mounted on a predetermined flat plate installed adjacent to the die coating unit (step S120).

Subsequently, the die of the die coating means is transferred from the upper portion of the transparent film along the longitudinal direction of the transparent film, and at the same time, when the hard coating liquid is applied to the surface of the transparent film through the die, continuous and uniform hard along the longitudinal direction of the transparent film is obtained. A coating film is formed (step S130).

The transparent film on which the hard coat film is formed through the above process is subsequently subjected to a drying process and a hardening process of solidifying the coating film, thereby completing the hard coating process (step S140). Here, the drying process of removing the solvent of the hard coating film may be performed by irradiating near infrared rays (NIR) with relatively excellent thermal action characteristics, or by applying an electric heater or hot air to the coating film, and the curing process may be ultraviolet rays. It can be carried out through investigation.

On the other hand, Figure 2 schematically shows the configuration of a transparent film hard coating apparatus for a display according to a preferred embodiment of the present invention.

Referring to FIG. 2, the present invention supports a flat plate 10 and a fixing means 11 supported from the bottom to horizontally mount the transparent film 1 for display, and a hard coating solution on the upper surface of the transparent film 1. Die coating means 12 to apply, and a dry curing machine (see 14 in FIG. 4) for drying and curing the coating film (2) formed on the transparent film (1).

The fixing means 11 for fixing the transparent film 1 on the flat plate 10 may be configured to suck the transparent film 1 in a vacuum manner and to fix the transparent film 1 on the flat plate 10. There may be variations.

Additionally, in the present invention, an adhesive roll 5 as shown in FIG. 3 may be further provided to perform the foreign matter removing process on the transparent film 1 of the step before being placed on the flat plate 10. Here, the pressure-sensitive adhesive roll 5 is rotatably installed to continuously remove the foreign matter in the longitudinal direction with respect to the transparent film 1 supplied with the pressure-sensitive adhesive on the outer peripheral surface thereof.

The die coating means 12 accommodates the hard coating liquid therein, while one side is provided with a die 12a serving as a discharge portion of the hard coating liquid.

It is preferable that the hard coating solution provided in the die coating means 12 includes various known additives including an acrylate monomer, a solvent, and a curing agent. Here, the viscosity of the hard coating liquid is preferably in the range of 10 ~ 10000cps considering the smooth hard coating liquid discharge operation in the die (12a), excessive flow prevention on the surface of the transparent film (1).

As the die 12a, a conventional T-die may be preferably used, but the present invention is not limited thereto, and various modifications may be made. Here, the thickness of the coating film 2 on the surface of the transparent film 1 is conveniently controlled by adjusting the distance between the lower end of the die 12a and the flat plate 10 or by adjusting the feeding speed of the die 12a and the amount of coating liquid discharged per unit time. Can be adjusted.

The die 12a receives a driving force from the transfer unit 13 and is horizontally transferred along the longitudinal direction of the transparent film 1. Here, of course, the present invention may be modified to horizontally move the flat plate 10 using the transfer part 13 while the die 12a is fixed.

The dry curing machine 14 for drying and curing the coating film formed on the transparent film 1 may include a curing device such as an ultraviolet generator together with a near infrared irradiation device or a drying device such as an electric heater or a hot air blower.

Then, the operation of the transparent film hard coating apparatus according to a preferred embodiment of the present invention having the configuration as described above will be described.

According to the present invention, the transparent film 1 to be coated is fixed on the flat plate 10 in a horizontal state by using the fixing means 11 of the vacuum method, and the die coating means 12 hard. In addition to the coating solution, a setting treatment for the coating process is performed by placing the die 12a of the die coating means 12 at a predetermined gap on the plate 10.

Therefore, the transfer part 13 continuously transfers the die 12a horizontally along the longitudinal direction of the transparent film 1, and at the same time, the hard coating liquid is fixed on the transparent film 1 using the die coating means 12. When supplied at a pressure and applied, the coating film 2 is continuously and uniformly formed on the upper surface of the transparent film 1.

The transparent film 1 on which the coating film 2 is formed through the above process is subsequently subjected to a drying process and a curing process through the dry curing machine 14.

Additionally, the present invention inverts the top and bottom surfaces of the transparent film 1 having the hard coating completed through the dry curing machine 14 so that the above process is performed again, but the coating liquid provided in the die coating means 12 is changed. By changing the composition of the film or by setting the gap between the die 12a and the flat plate 10 differently from the previous coating process, as shown in FIG. 5, the transparent films having the coating films 12a and 12b having different patterns on both surfaces thereof ( 1) can be obtained.

Hereinafter, in order to help the understanding of the present invention, a specific embodiment of the present invention and a conventional flow coating method (comparative example) will be described by comparing with each other under the same conditions.

Example

First, a polycarbonate transparent film having a width of 1 meter, a length of 2 meters, and a thickness of 500 μm is passed through an adhesive roll using a conveyor to remove foreign substances adhering to the film surface, and the plasma is transported at a traveling speed of 5 m per minute while transferring the transparent film. The surface pretreatment process was performed.

Next, the hard coating solution was applied while moving the die from one edge of the transparent film to the other edge of the transparent film while the transparent film was fixed on the flat plate by using a vacuum. At this time, the hard coating solution was a liquid containing a solvent and an additive in the acrylate monomer, the viscosity was set to 150cps.

After applying the coating liquid, the transparent film was passed through a dry curing machine equipped with a near infrared (NIR) lamp to perform a drying process to remove the solvent of the coating layer of the hard coating liquid, and after drying, curing was performed using an ultraviolet (UV) lamp. The process was carried out.

According to the above-described series of processes, the pencil hardness of the hard coat film was 1H or more, and a transparent film having a hard coat film having a thickness of 5 μm and a thickness deviation of 5% or less could be manufactured.

Comparative example

First, a polycarbonate transparent film having a width of 1 meter, a length of 2 meters, and a thickness of 500 μm is passed through an adhesive roll using a conveyor to remove foreign substances adhering to the film surface, and the plasma is transported at a traveling speed of 5 m per minute while transferring the transparent film. The surface pretreatment process was performed.

Subsequently, a process of applying the coating liquid by using a flow coating method in a state in which the transparent film was upright was performed. At this time, the hard coating solution was a liquid containing a solvent and an additive in the acrylate monomer, the viscosity was set to 150cps.

After the coating solution was applied, the coating solution was left at room temperature for several minutes to allow the coating to flow down the transparent film. Next, the transparent film was passed through a dry curing machine equipped with a near infrared (NIR) lamp to carry out a drying step of removing the solvent of the hard coating liquid coating layer, and after drying, a step of curing using an ultraviolet (UV) lamp was performed. .

According to the above process, the transparent coating film having a hard coating film having a pencil hardness of 1H or more and a thickness variation of 5 to 30 µm having a very high thickness deviation was hardened.

Table 1 shows a comparative example of the coating properties according to the embodiment of the present invention and the flow coating process (comparative example) as described above.

Transparent Film Characteristics Hard Coating Liquid Coating film characteristics Kinds Length [m] / width [m] Thickness [㎛] ingredient Viscosity [cps] Pencil hardness (H) Thickness [㎛] Example Polycarbonate 1/2 500 Acrylate Monomer / Solvent / Additive 150 1 or more 5 ± 5% Comparative example Polycarbonate 1/2 500 Acrylate Monomer / Solvent / Additive 150 1 or more 5-30

Referring to Table 1, in the case of the conventional flow coating method, it can be seen that the thickness of the coating film is very large as 5 ~ 30㎛ for each portion on the transparent film, the deviation is very large, in contrast to the implementation according to the present invention In the example it can be seen that the thickness of the coating film has a very small deviation of 5㎛ ± 5% for each part on the transparent film.

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto and will be described below by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims.

As described above, according to the present invention, a transparent film for display having a coating film having a uniform thickness for each part of the transparent film can be manufactured.

In addition, according to the present invention, in addition to the single-sided hard-coated transparent film, one side of the transparent film can be hard-coated, the other side can perform a primer coating, such as to produce a transparent film of various coating patterns as needed have.

The present invention can also selectively use as much hard coating liquid as necessary, corresponding to the area of the transparent film, there is also economical to reduce the loss of the hard coating liquid.

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to

1 is a flowchart illustrating a process of performing a hard coating method of a transparent film for a display according to a preferred embodiment of the present invention.

Figure 2 is a schematic configuration diagram of a hard coating device for a transparent film for a display according to an embodiment of the present invention.

Figure 3 is a schematic view showing a process for removing foreign matter on the surface of the transparent film.

Figure 4 is a schematic view showing a drying process for the coating film of the transparent film.

5 is a cross-sectional view showing a structure in which a coating film of different properties is formed on both sides of the transparent film according to the present invention.

<Description of main reference numerals in the drawings>

1.transparent film 2,2a, 2b ... coating film

5 ... adhesive roll 10 ... flat plate

11 fixing means 12 die coating means

13 Transfer unit 14 Drying machine

Claims (7)

Applying a hard coating solution to the surface of the transparent film for display using the die coating means while transferring any one of the die or the plate of the die coating means in a state that the display transparent film to be a hard coating object horizontally fixed on the flat plate First step; A second step of drying the hard coating solution coating layer; And Hard coating method of the transparent film for a display comprising; a third step of curing the coating layer. The method of claim 1, wherein in the first step, Hard coating method of the transparent film for display, characterized in that the hard coating solution contains an acrylate monomer, a solvent and a curing agent. The method according to claim 1 or 2, Hard coating method of the transparent film for display, characterized in that the viscosity of the hard coating solution corresponds to the range of 10 ~ 10000cps. The method of claim 1, wherein before the first step, Passing the transparent film for display through an adhesive roller to remove the foreign matter; Hard coating method of the transparent film for display, characterized in that performed. The method of claim 1, Hard coating method of the transparent film for display, characterized in that the thickness of the transparent film for display corresponds to 500 ~ 1500㎛. A flat plate for horizontally placing the transparent film for display, which is a hard coating object, and fixing means for fixing the transparent film on the flat plate; Die coating means for applying a hard coating liquid to the surface of the transparent film through a predetermined die; A transfer unit for transferring any one of the die and the flat plate so that a hard coating liquid coating process is continuously performed along the longitudinal direction of the transparent film for display; Hard coating apparatus for a transparent film for display comprising a dry hardener for drying and curing the hard coating liquid coating layer formed on the display transparent film. The method of claim 6, The fixing means is a hard coating apparatus for a transparent film for display, characterized in that for fixing the transparent film for display on a flat plate by vacuum suction method.