JPS6295171A - Coater - Google Patents

Abstract

PURPOSE:To eliminate an uneven coating by interposing plural feeders having the function of deaeration between a header and a die, discharging a paint from the feeders together with air bubbles, and controlling the discharge flow rate to uniformize the flow rate of the paint. CONSTITUTION:The die 4 for spraying the paint 3 on a web 2 which is wound on a backing roll 1 and traveled is provided below the roll 1 in parallel, and a header 6 for supplying the paint is furnished in parallel with the die 4. The paint is respectively introduced through plural distributor pipes 5 branched from the header 6, and the plural feeders 7 for supplying the paint are provided in parallel with the die 4. The upper end of the feeder 7 is communicated with the die 4. The feeder is provided with the bottomed main body 7a of an appropriate shape having a circular horizontal cross section of the inner periphery, a paint inlet for tangentially introducing the paint sent through the pipe 5 in the vicinity of the bottom part of the peripheral wall of the main body, an air bubble outlet 8 in the vicinity of the central part of the bottom surface of the main body, and further a flow regulating valve 9 on the outside of the outlet 8.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a coating device for applying paint to a web of paper or plastic film 4.

<Prior art and its problems> Vt1t, which applies paint such as clay to a web such as paper or plastic film! As one type of coating machine, a coating machine called a fountain coater is widely used. FIG. 4 is a sectional view of a conventional coating machine.

In Fig. 4, 1 is a backing roll, 2 is a web, 3 is a paint, 4 is a die, 5 is a distributor pipe,
6 is a header.

The web 2 is wound 11 around the outer periphery of a backing roll 1 whose outer periphery is wrapped with an elastic body such as rubber, and is run. A die 4 is provided below the backing roll 1 and parallel to the backing roll. A nozzle 4a is provided in the upper part of the die 4, and the impregnated material 3 inside is
The pressure is maintained at 0.3 to 0.5 kg/am2G, and the paint 3 is sprayed onto the web 2 which is supported by the backing roll 1 and runs.

The web 2 coated with the paint 3 is dried in the next step.

A large number of distributor pipes 5 are connected to the die 4 at a required pitch in the width direction, and the distributor pipes 5 are connected to a header 6 provided parallel to the die 4. The paint 3 is supplied to the die 4 through the distributor pipe. Although it is not shown in Fig. 4, immediately after coating the web 2 with the paint 3 using the die 4, use a blade or air knife to scrape off the excess paint to keep the amount of coating on the web 2 constant. did)7
Fountain blade coaters and fountain air knife coaters are also used.

In such conventional coating applications, since the paint 3 is not uniformly ejected from the nozzle 4a of the die 4 in the width direction, the web 2
There is a problem in that coating unevenness occurs in the width direction. Although such coating unevenness can be reduced to some extent by scraping off with the blade or air knife described above, the unevenness cannot necessarily be completely eliminated, and this is a serious problem in the coating machine shown in Fig. 4, which does not have a rough blade or air knife. Become. The main reason why the amount of paint ejected from the nozzle 4a of the die 4 is not uniform in the width direction is that the flow rate of the paint 3 flowing through the distributor pipe 5 differs for each pipe. Countermeasures have been taken, such as changing the shape of the header and making the paint inlet of the header come from two places, the front and the back, but these have not always been successful, and the Even if good results are obtained with one flow rate or viscosity, the problem remains that the results are poor with other flow rates and viscosities. On the other hand, air gets mixed into Paint 3 during the paint mixing process due to stirring, etc., and exists as small air bubbles, and there is a problem that such air bubbles cause coating defects such as skip coating on the coated surface. . Degassing methods to remove the air bubbles that occur before the paint 3 reaches the die 4 include adding an antifoaming agent, increasing the retention time in the paint tank to allow the air bubbles to rise naturally, and other methods. Utility Model Publication No. 58-58865) has been proposed in which air bubbles are removed by devising the shape of No. 4, but all of them are insufficiently effective, especially for highly viscous paints.

<Object of the Invention> The present invention has been devised in view of the problems of the prior art, and therefore, a plurality of feeders having a degassing function are interposed between the header 6 and the die 4, and air bubbles are removed from the feeder. By discharging the paint and adjusting the discharge flow rate, the flow rate of the paint flowing from each feeder into the die 4 is made uniform, thereby achieving coating without uneven coating and without coating defects such as skip coating. The purpose is to provide a machine.

('R' and 'R' of the Invention) In order to achieve the above object, the coating machine of the present invention has a structure including a backing roll, which is provided below the backing roll in parallel, and sprays paint onto a web that is wound around the backing roll and runs. a die to which the paint is attached, a header that is provided parallel to the die and supplies paint, and a plurality of pipes that introduce paint through a plurality of distributor pipes that branch from the header and supply the paint in parallel to the die. The feeder has a main body with an appropriate shape and a bottom, the upper end of which communicates with the die, and a horizontal cross section of the inner periphery is circular, and the distributor pipe is located near the bottom of the peripheral wall of the main body. It has a paint inlet that tangentially introduces the paint sent through it, and also has a bubble outlet near the center of the bottom of the main body, and a flow @ adjustment valve is connected to the outside of the bubble outlet. It is characterized by this.

The paint flows tangentially into the approximately cylindrical feeder body, generating a vortex inside the body, and the centrifugal force causes air bubbles that gather at the center of the body to be collected together with the paint through a bubble outlet provided near the center of the bottom of the body. leak to the outside. In addition, the flow rate of paint flowing out from the bubble outlet is controlled by a control valve. Since deaeration is performed in this way, coating defects such as skip coating do not occur, and by adjusting the discharge flow i, the paint flow W flowing into the die from each feeder is made uniform, so that the paint ejected from the die is The flow rate becomes uniform and uneven coating is eliminated.

<Example> An example of the coating machine of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of the coating machine of the present invention, FIG. 2 is a perspective view, and FIG. 3 is a sectional view of the feeder section in FIG. In Figure 3, 1 is a backing roll, 2 is a web, 3 is a paint, 4 is a die, 5 is a distributor pipe, 6 is a header, 7 is a feeder,
8 is a paint discharge pipe, and 9 is a control valve.

In addition, the present invention applies to the paint supply system from the header 6 of the conventional coating machine to the die 4 via the distributor pipe 5.
A feeder 7 having a deaeration function is interposed between the distributor pipe 5 and the die 4, and a part of the paint is discharged from the feeder 7 together with air bubbles. Therefore, the same reference numerals are used for the same parts as in the conventional coating machine, and the explanation will be omitted.

The paint outflow lower d of the feeder 7 is connected to the die 4 at a required pitch. A paint discharge pipe 8 is provided in communication with the bottom of each feeder, and a control valve 9 is provided in the discharge pipe 8.
is provided.

The feeder 7 is connected to the header 7 via the distributor pipe 5.
is connected to. The paint 3 is supplied to the header 6 from both the front and back sides as shown in FIG.

The feeder 7 includes a cylindrical main body 7a having a bottom 7e, and an annular body 7b surrounding the main body 7a near the bottom.

A hole 7f is bored in the center of the bottom 7e, and a paint discharge pipe 8 is connected to the hole 7f. A distributor pipe 5 is tangentially connected to the annular body 1b. Two tangential slits 7C are provided in a portion surrounded by the annular body 7b near the bottom of the main body 7a.

Next, the functions of the feeder 7 and the control valve 9 will be explained.

From header 6 to distributor 5 to feeder 7
The paint 3 that has flowed into the annular body 7b flows into the main body 7a through the slit IC while making a circular motion within the annular body 7a. The slit 7C is tangentially formed near the bottom 7e of the main body 7a, and the paint 3 flowing through the slit IC generates a vortex within the main body 7a. 1000 by the vortex
When a centrifugal force of about G acts on the paint, light air bubbles gather in the center.

The air bubbles gathered in the center are 0.3 to 0.5k in that part.
The pressure is approximately g/cm2 G, and the paint 3 flows out through the hole 7f drilled in the center of the bottom 7C, through the discharge pipe 8 and the control valve 9. Therefore, the paint 3 supplied from the feeder 7 to the die 4 contains almost no air bubbles, and therefore no defects such as skip coating occur on the coated surface of the web 2.

In addition, if there is a part in which the coating amount is large in the width direction of the coated surface of the web, the amount of paint 3 discharged from the feeder 7 corresponding to that part can be increased by opening the control valve 9. The diversion of the paint 3 supplied to the die 4 decreases, and accordingly, the paint 3 from the nozzle 4a of that part decreases.
The amount of outflow is reduced, and uniformity of the amount of application is achieved.

<Effects of the Invention> As described above, the coating machine of the present invention has the following effects.

(1) In the paint supply system from the header to the die via the distributor pipe, a feeder with a deaeration function was installed between the distributor pipe and the die.
There are almost no air bubbles in the paint supplied to the die, so coating defects such as skip coating do not occur.

■ The flow rate of the paint discharged from the feeder along with air bubbles is adjusted by the control valve, and the outflow of the paint flowing into the die from each feeder is adjusted, so that the paint jetted from the nozzle of the die is uniform in the width direction. This prevents unevenness in the amount of paint applied to the web in the width direction.

■ Each distributor is equipped with a deaeration device.
The throughput of each deaerator is smaller than when the deaerator is installed in front of the header, and the diameter can therefore be smaller, so even with the same pressure loss (i.e. flow velocity at the main body inlet), the centrifugal force is large and the deaeration efficiency is high. .

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the coating machine of the present invention, FIG. 2 is a perspective view, and FIG. 3 is a cross-sectional view taken along the line -■ in FIG. FIG. 4 is a sectional view of a conventional coating machine. 1... Backing roll 2... Web 3... Coating bowl 4... Die 5... Each distributor 6... ...Header 7 ...Feeder 8 ...Discharge pipe 9 ...Adjustment valve Fig. 1 Fig. 3 -7Q Fig. 2 - J

Claims (1)

[Claims] a backing roll, a die that is provided parallel to the lower part of the backing roll and sprays paint onto a web that is wound around the backing roll and runs; a header that is provided parallel to the die and supplies the paint; The feeder is equipped with a plurality of feeders that introduce paint through a plurality of distributor pipes branching from the header and supply the paint to the die in parallel.The feeder has an upper end communicating with the die, and a horizontal The main body has a suitable shape with a circular cross section and a bottom, and has a paint inlet near the bottom of the peripheral wall of the main body for tangentially introducing the paint sent through the distributor pipe, and a paint inlet in the center of the bottom of the main body. 1. A coating machine having a bubble outlet near the bubble outlet, and further comprising a flow control valve connected to the outside of the bubble outlet.