JPS6010692Y2 - Coating equipment for films and tapes - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of an apparatus for continuously applying a coating liquid to films, tapes, etc.

When continuously applying a coating liquid to a long sheet such as a film or tape, as shown in FIG.
It is known that the tape T is run along a roll 1 and the coating thickness is determined by a slit 5 between the roll 1 and the tip 4 of a doctor knife.

In the figure, reference numeral 6 denotes a carrier such as a flat belt, which is necessary when the film or tape T is made of a low-strength material, such as a porous thin film.

By the way, in the above coating method, according to the experience of the present inventor, it is inevitable that pinholes often occur on the coating film.

The main reason for the occurrence of pinholes is that the liquid in the coating liquid pool 3 flows and rotates as shown by the arrow due to the running of the film and tape T, and air is trapped in the liquid in the coating liquid pool 3. This is thought to be due to the formation of bubbles inside.

On the other hand, as a coating method that does not cause pinholes, a method using a so-called T-shaped die, which is a slit-shaped die whose discharge port extends over the entire width of the film or tape, is known.

However, this method has drawbacks such as uneven coating thickness due to minute fluctuations in the film or tape, and vertical streaks if foreign matter adheres to one location at the discharge port. Not suitable for quality coating.

An object of the present invention is to provide a coating device for films and tapes that does not generate pinholes and has a uniform coating thickness.

The coating device of the present invention uses a T-die, etc. to apply the same coating liquid as the coating liquid pool onto the running film or tape in advance, creates a smooth coating liquid surface on the surface of the film or tape, and then transfers the coating liquid to the roll. It is characterized in that the thickness of the coating liquid is regulated through the coating liquid pool formed by the liquid partitioning member and the slit.

Examples of the present invention will be described below.

In FIG. 2, 11 is a main roll, 12 is a doctor knife, 13 is a coating liquid reservoir, 14 is a carrier stretched over the main roll, 15 is a slit, and 16 is a T-shaped die.

This T-shaped die 16 is disposed in contact with the film or tape T ahead of the main roll 11 in time, and applies a liquid of the same quality as the coating liquid in the coating liquid reservoir.

The T-shaped die 16 is connected to a coating liquid tank (not shown) via a tube made of polyethylene, nylon, or the like, and the coating liquid is pumped to the tie by a pump such as a gear pump or by air pressure.

The thickness of coating by the T-shaped die 16 may be smaller than the final coating thickness, and the filter or tape whose surface is coated with the coating liquid passes through the coating liquid reservoir 13 and is regulated to a predetermined thickness by the slit 15.

FIG. 3 shows another embodiment of the present invention in which the T-shaped die 16 is brought into contact with the lower surface of the film or tape.

According to the present invention, since the coating liquid is applied thinly to the surface of the film or tape by the T-shaped die 16 in advance, air bubbles and pinholes are not generated, and even if vertical streaks occur during coating, the coating liquid passes through the coating liquid pool 13. As a result, vertical streaks are eliminated, and since the surface of the film or tape or the porous interior is already wet and the coating liquid is of the same quality, the coating liquid pools 1.
The phenomenon of fluid rotation caused by air being trapped inside 3 has been resolved.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a conventional example, and FIGS. 2 and 3 are side views showing an embodiment of the present invention. 11...Main roll, 12. Curved knife, 13...Coating liquid reservoir, 16...T
Mold die, T...film, tape etc.

Claims (1)

[Scope of utility model registration request] In a device in which a coating liquid pool is formed by a roll and a coating liquid partition member, and a film or tape is run through the coating liquid pool and a slit at the bottom of the coating liquid pool, before the film or tape reaches the roll. A coating device for films and tapes, characterized in that a die is provided for coating the surface of the film or tape with a liquid of the same quality as the above-mentioned coating liquid.