JPH0244873Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hot melt coater capable of coating in small amounts and at high speed.

A hot melt coater is a coating machine that melts resin, etc. and applies it to the surface of paper, cloth, film, etc. It can be used to coat adhesive tapes, hot melt tapes, gummed tapes, sheets for binding fiber materials, and various board materials. Used for manufacturing laminated sheets, etc.

Recently, lightweight and strong materials made by bonding fibrous materials such as carbon fibers with hot melt resin are being developed, and as a result, there is a need for hot melt coaters that can coat small amounts and coat at high speed. Although the coater is an emerging field, it cannot be said that the technology is sufficiently established, and at present, nothing that can meet the above requirements has been developed.

FIGS. 1 and 2 show conventional examples of hot melt coaters. The one shown in FIG. The roll e and each of the rolls b, c, and d are rotated as shown in the figure, and the coating liquid f melted by heating is scooped up by the pick-up roll b and applied to the surface of the coating roll c, and then the measuring roll d and the coating roll This method applies the coating by pressing the coating roll c against the web g while measuring the coating amount by the gap size between the coating roll c and the coating nozzle (die) h.
The coating liquid is heated, the hot melted coating liquid is ejected towards the web g, and the coating amount is set by the gap between the backup roll e and the lip part i of the coating nozzle. There is a problem.

In other words, in the reverse roll coater type shown in Fig. 1, the dimensional accuracy fluctuates greatly due to roll heating.
It is not suitable for small-volume coating because the roll gap cannot be made very small, and it is also unsuitable for high-speed coating because roll vibration and coating liquid scattering occur.
During coating, the web and outside air remove heat from the coating liquid, causing the liquid temperature to drop suddenly, causing uneven coating and bubbles on the coating surface, reducing quality.

In addition, in the die coater method shown in Figure 2, as with the reverse roll coater method, the temperature of the coating liquid decreases during coating, which increases the viscosity of the coating liquid and makes it difficult to smooth the coating liquid due to rips. Not only is it unsuitable for coating, but it is also not suitable for high-speed coating when the lip part i is worn out because it cannot be easily replaced. This occurs easily and quality deteriorates.

In view of the above, the present invention is a hot melt that heats the web before coating to prevent the temperature of the coating liquid from decreasing during coating, making it possible to coat small amounts and at high speed, and to improve the quality of the coated surface. This was done to provide a coater.

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 3 shows the present invention, in which 1 is a back-up roll, 2 is a coating nozzle, 3 is a blade holder, 4 is a metering blade, 5 is a receiving pan, 6 is a coating liquid tank, 7 is a supply pump, and 8 is a The filter, 9 is a preheating roll, and 10 is a guide roll, and in the above equipment, the coating liquid tank 6, supply pump 7, coating nozzle 2, and receiving pan 5 are heated by a separate heating device (however, the receiving pan is not heated). ), the coating liquid 11 supplied in a molten state to the coating liquid tank 6 is sent to the coating nozzle 2 by the supply pump 7 and sprayed onto the surface of the web 12 to be applied. is scraped off with a measuring blade 4 to obtain a predetermined coating amount, and the scraped coating liquid is received by a receiving pan 5 and returned to a coating liquid tank 6, and the back-up roll 1, coating nozzle 2, A blade holder 3, a measuring blade 4, a receiving pan 5, a preheating roll 9, and a guide roll 10 are mounted on a side wall with a web inlet 13 and a viewing window 14, a ceiling with a web exit 15, and the viewing window 14 is replaced with a transparent plate 16.
Heating chamber 1 covered with a cloth to prevent hot air from escaping.
7, and the temperature in the heating chamber 17 is constantly controlled by a circulation fan 18 and a heater 19.
The liquid temperature can be controlled to about 2, and the backup roll 1 and preheating roll 9 can be heated with a separate heating device.

With the above configuration, the web 12 entering the heating chamber 17 from the web inlet 13 is heated by the preheating roll 9,
After the coating liquid 11 is sequentially heated by the back-up roll 1 and applied by the coating nozzle 2 in an environment with a temperature similar to that of the coating liquid, and the predetermined coating amount is set by the metering blade 4. Web exit 15
Sent from

Since the web 12 is preheated and the coating is performed in the heating chamber 17 in this way, the heat of the coating liquid 11 is not taken away by the web 12 or air during coating and the temperature of the coating liquid 11 does not drop. The increase in viscosity can be prevented, the coating liquid can be easily scraped off with the metering blade 4, and it also exhibits effects such as improving the smoothness of the coated surface, preventing streaks, and removing air bubbles, resulting in a high-quality hot melt coating.

Furthermore, since the above-mentioned embodiment uses a metering blade 4 that is an easily replaceable and inexpensive consumable item, operating costs do not increase even when high-speed coating is performed, and economical hot melt coating can be performed. can.

It should be noted that the present invention is not limited to only those shown in the above embodiments, and for example, in FIG. Alternatively, the web 12 may be heated in a preheating zone of the heating chamber 17 and fed directly to the backup roll 1 as shown in phantom.

According to the present invention, as mentioned above, (i) it is possible to prevent the increase in viscosity due to a drop in the temperature of the coating liquid during coating, and it is easier to scrape off the coating liquid with a metering blade, so the amount of coating (coating thickness) can be reduced; In addition to improving coating surface smoothness and preventing streaks,
(ii) Since the coating is applied in a heating chamber, hot melt coating is similar to coating at room temperature, and various coating methods can be applied to hot melt coating. , it is possible to diversify hot melt products.

It can produce excellent effects such as

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a conventional hot melt coater, and FIG. 3 is an explanatory diagram of an embodiment according to the present invention. 1...Backup roll, 2...Applying nozzle, 4...Measuring blade, 6...Coating liquid tank, 9
... Preheating roll, 11 ... Coating liquid, 12 ... Web, 17 ... Heating chamber, 18 ... Circulation fan, 19
……heater.

Claims (1)

[Scope of utility model registration request] A coating section device for applying the coating liquid to the web is provided in the heating chamber, a heating means is provided for heating the web before coating, and a device is provided for controlling the room temperature of the heating chamber to about the temperature of the coating liquid. hot melt coater.