Slot die coating apparatus

Abstract

The present application relates to a slot die coating apparatus and, more particularly, to a slot die coating apparatus which can ensure the coating stability of a substrate film by reducing pressure oscillations within a vacuum chamber when slot die coating is carried out. The slot die coating apparatus according to the present application can effectively dampen pressure oscillations within a vacuum chamber by connecting a pressure oscillation reducing tank to the vacuum chamber and thus can ensure the coating stability of a substrate film, resulting in a reduction in the proportion of defective products.

Claims

1. A slot die coating apparatus comprising: a slot die configured to supply a coating liquid to a base film; a vacuum chamber configured to hold a gas volume V.sub.1 and installed at a front end of the slot die and having a gap formed between the vacuum chamber and the base film; a first pipe connected to a vacuum pump and connected to the vacuum chamber; a pressure oscillation reducing tank configured to hold a gas volume V.sub.2; and a second pipe connected to the pressure oscillation reducing tank and to the first pipe, or connected to the pressure oscillation reducing tank and to the vacuum chamber; wherein V.sub.1V.sub.2 and together the vacuum chamber and the pressure oscillation reducing tank are configured to provide a vacuum environment to the slot die and which satisfies the following Formula 2:
V1+V2A(P2P1)DW[Formula 2] wherein V1 represents a volume (m3) of the vacuum chamber, V2 represents a volume (m3) of the pressure oscillation reducing tank, A is 1 m3/N to 20 m3/N, P1 represents a pressure (N/m2) in the vacuum chamber, P2 represents atmospheric pressure (N/m2), D represents a width (m) of the gap formed at the vacuum chamber, and W represents a horizontal length (m) of a coating layer which is formed after the substrate film is coated.

2. The slot die coating apparatus of claim 1, further comprising a roll around which the base film is supplied to the slot die.

3. The slot die coating apparatus of claim 1, wherein the volume of the pressure oscillation reducing tank V.sub.2 is two times or more the volume of the vacuum chamber V.sub.1.

4. The slot die coating apparatus of claim 1, wherein the volume of the pressure oscillation reducing tank V.sub.2 is 10 times or more the volume of the vacuum chamber V.sub.1.

5. The slot die coating apparatus of claim 1, wherein the volume of the pressure oscillation reducing tank V.sub.2 is 20 times or more the volume of the vacuum chamber V.sub.1.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a configuration diagram schematically illustrating a slot die coating apparatus according to conventional art.

(2) FIG. 2 is a configuration diagram schematically illustrating a slot die coating apparatus according to an exemplary embodiment of the present application.

(3) FIG. 3 is a configuration diagram schematically illustrating a slot die coating apparatus according to another exemplary embodiment of the present application.

DESCRIPTION OF REFERENCE NUMBERS OF MAJOR ELEMENTS

(4) 10: roll 12: base film 14: slot die 16: coating layer 20: vacuum chamber 22: first pipe 24: pressure gauge 26: second pipe 30: pressure oscillation reducing tank

BEST MODE OF THE INVENTION

(5) Hereinafter, the present application will be described in detail through a comparison between Example in accordance with the present application and Comparative example not in accordance with the present application. However, the present application is not limited to Example disclosed below.

Example

(6) Using the slot die coating apparatus having a structure according to FIG. 2, with a gap of 0.1 mm, a volume of the vacuum chamber of 0.14 m.sup.3 and a volume of the pressure oscillation reducing tank of 0.14 m.sup.3, a coating layer was formed on one surface of the based film made of an acryl film using a coating liquid in which a solvent was toluene and a solute was acrylate.

Comparative Example

(7) A coating layer was formed under the same conditions as in the above Example except that a slot die coating apparatus having the structure according to FIG. 1 in which, unlike the slot die coating apparatus used in the above Example, the pressure oscillating tank was not connected to the vacuum chamber.

(8) The coating layers of the above Example and Comparative example were evaluated on the following basis by observing unevenness of the coating layers with the naked eye.

(9) <Evaluation Basis>

(10) O: Unevenness of coating layer on the surface of the acryl film is not checked by the naked eye.

(11) X: Unevenness of coating layer on the surface of the acryl film is remarkably observed by the naked eye.

(12) The results of observation of the above Example and Comparative example are given in the following table 1.

(13) TABLE-US-00001 TABLE 1 Example Comparative example Degree of unevenness of coating O X

(14) As shown in table 1, it can be verified that the slot die coating apparatus according to the present application can effectively reduce the pressure oscillation in the vacuum chamber by connecting the pressure oscillation reducing tank to the vacuum chamber, and thus ensure the coating stability on the substrate film and reduce the defect rate of products.