JPH02214568A - Coating device - Google Patents

Abstract

PURPOSE:To prevent the deposition of a coating soln. on the end of a support and a roller by providing a thin-tube nozzle for blowing air against the coating soln. cross-linking part and a slit nozzle for expanding the coating soln. to the uncoated part at the end of a support from the inside of the coating surface. CONSTITUTION:The thin-tube nozzle 5 for blowing the injected air against the coating soln. cross-linking part to be formed between the support 1 and the soln. discharged from a slot and a slit nozzle 13 for spreading out the coating soln. to the uncoated part at the end of the support 1 from the inside toward the outside of the coating surface so as to form an uncoated part having 0.1-2mm width at the end of the support 1 are provided. By such a structure, the coating soln. is not deposited on the end of the support 1 and the roller 3 even when the width of the coater slot is larger than that of the support 1 and the end of the support 1 is thickly coated, hence the production efficiency is not decreased, the product quality is not deteriorated, and coating is carried out with high efficiency and yield.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to photosensitive materials such as photographic film, photographic paper, photolithography materials, magnetic recording materials such as magnetic recording tape, pressure-sensitive recording paper, heat-sensitive Regarding the improvement of an apparatus for applying a liquid coating composition (hereinafter referred to as "coating liquid") to a continuously running long flexible support (hereinafter referred to as "web") in the production of recording materials such as recording paper, More specifically, the present invention relates to a so-called extrusion type coating device that forms beads by discharging a coating liquid from an improved slot.

[Conventional technology]

Conventionally, various methods have been proposed as methods for applying a coating liquid to a continuously running web.

Generally, the coating process is divided into a part that transfers the coating liquid to the web (hereinafter referred to as the "application system") and a part that measures the coating liquid transferred to the web to the desired coating amount (hereinafter referred to as the "measuring system J"). Therefore, coating methods were classified based on the differences in application type and measurement type.

Based on differences in application systems, roller coating methods, dip coating methods, fountain coating methods, etc., and based on differences in metering systems, air knife coating methods, blade coating methods, bar coating methods, etc. have been known.

Among these, extrusion coating methods and bead coating methods have been used as precision coating methods in which the coater does not come into direct contact with the support.

Regarding coating methods and devices using extrusion silane type coaters, such as extrusion coating methods and bead coating methods, for example, Japanese Patent Publication No. 45-12390,
Special Publication No. 46-26236, Special Publication No. 47-2465
Extrus silane multilayer coating apparatus as disclosed in Japanese Patent Application No. 142643/1982, a single layer coating method as disclosed in Japanese Patent Application Laid-open No. 142643/1983, or
Many patents have been filed, including coating methods and apparatuses in which the ejection slot is located upward, as disclosed in Japanese Patent Laid-Open No. 95363 and Japanese Patent Application Laid-open No. 110776/1983.

Furthermore, as a countermeasure against thick coating at the ends of the web, Japanese Patent Application Laid-Open No. 54-142248 discloses a method of spreading a continuous coating layer using a jet air stream, or a method of spreading a continuous coating layer using a jet air flow, or a method of spreading a continuous coating layer using a jet air flow, or a method of spreading a continuous coating layer by using a jet air stream to remove thick coating parts that occur at both ends of the coating film. Japanese Patent No. 60-49949 discloses a method in which a thickly coated portion at the end of a coating film is expanded while being suctioned by a suction nozzle at the end of the web.

[Problem to be solved by the invention]

However, when applying a coating liquid to a web of arbitrary width within a certain slot liquid discharge opening width, a method and apparatus for adjusting coating liquid crosslinking according to the web radius must be used. However, even in that case, a phenomenon occurs in which the coating liquid adheres to the edge of the web, which further causes staining of the part of the backup roller that comes into contact with the web edge, which in turn causes the coating liquid to adhere to the edge of the web, which in turn causes staining of the part of the backup roller that comes into contact with the edge of the web. It can also stain the parts.

The purpose of the present invention is to solve the above-mentioned conventional problems, prevent such staining of the web edge and the concomitant staining of the backup roller, and take measures against the thickly coated portion of the web edge.
The objective is to provide a coating device with excellent production efficiency and product yield.

[Means and effects for solving the problems] The above-mentioned object of the present invention is to provide a coating device that supplies a coating liquid to the surface of a continuously running support through a slot, in which a 0.1 to 2 m long coating is provided at the end of the support.
A capillary nozzle directs gas to the coating liquid bridge formed between the support and the liquid discharge port of the slot so as to create an uncoated portion of the coating surface at the end of the support. This is achieved by a coating device characterized by being provided with a slit nozzle that pushes and spreads the coating liquid at the end of the coating film from the inside to the outside.

In the coating device according to the present invention, which supplies a coating liquid from a slot onto the surface of a continuously running support, the liquid is discharged between the support and the slot so as to create an uncoated part of 001 to 2M at the end of the support. The position of the capillary nozzle is determined by the diameter of the capillary, wind speed,
! ! The cloth speed varies depending on the physical properties of the coating liquid, the amount of coating, etc., so it shows how to arrange it so that the results can be obtained.

In addition, in the present invention, spreading the coating liquid at the end of the coating film to the uncoated part at the end of the support means that when the uncoated part is created by injecting gas from the capillary nozzle, the coating liquid at the end of the coating film is spread. If it spreads naturally to uncoated areas, it is fine to leave it as is (this actually happens), but if a thick coating of the coating remains at the edge of the coating film, it is recommended to flatten and spread the thick coating later. Necessary for process efficiency and quality. therefore,
As an apparatus for this purpose, a slit nozzle directed from the inside to the outside of the coating surface is used to push and spread the coating liquid of the coating film, as already disclosed in Japanese Unexamined Patent Publication No. 54-142248 or Japanese Utility Model Application No. 60-49949. To achieve this purpose, it is necessary to provide a device or a device that spreads the coating liquid at the end of the coating film while sucking it with a suction nozzle at the end of the web.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a perspective view of one embodiment of the coating device of the present invention (
Fig. 3 is a) and a side sectional view (b).

In FIG. 1, the coater is an extrusion type coater 4, which forms coating liquid bridges on the lower surface of the web 1 and performs coating.

Further, the gas injected from the nozzle is applied to the coating liquid bridging portion formed between the web of the web edge 7 and the coater lip surface 8 using the thin tube nozzle 5 .

The above gas makes it possible to form the coating liquid bridge, which is normally fixed at the web edge 7, 0.1 to 2 m further inward from the web edge. The gas injected from this nozzle is 0.1 to 15 m /
It is preferable to project at a wind speed of 1 to 5 m/sec, more preferably 1 to 5 m/sec. If the wind speed is too high, the coating liquid at the end of the bead will be blown off and turned into a mist, disturbing the edge of the coating film and causing damage to the edge of the coating film. This causes phenomena such as becoming saw-shaped.

Moreover, if it is too low, the effect will naturally be lost and the end of the bead will be fixed at the end of the web edge 7.

The nozzle has a diameter of 0.1 to 4 m, preferably 0.1 m.
A cylindrical nozzle with a diameter of 5 to 2 rm is preferred, but a nozzle with another shape, such as a flat nozzle, can also be used.

Further, the thin tube nozzle 5 can spray from the coated side of the web as shown in Fig. 1, or from the opposite coated side of the web as shown in Fig. 2.

Further, when the width of the web l moves from side to side, the narrow tube nozzle 5 detects the position of the edge 7 of the web with an edge position detector 9 as shown in FIG.
By moving the driver 11 along the guide rail 12 in response to the left and right movement of Preferably, a device for automatically moving in the direction is provided.

A device for pushing and spreading the coating solution to the end of the web after forming the uncoated portion after coating is as shown in Japanese Patent Application Laid-open No. 142248/1983 or as shown in FIG. 3(a).

As shown in (g)), the slit nozzle 13 is directed from the inside of the coating surface to the outside of the coating surface. Gas piping 1 for the ejected air
4.

It is also possible to use a method such as that disclosed in Japanese Utility Model Application Publication No. 60-49949, in which a suction nozzle is used to spread the thick coating at the end of the coating film while sucking it.

As shown in FIG.
It is preferable to use a device that automatically moves the device in the width direction in accordance with the position of the device.
The coating liquid in the present invention is not particularly limited, and includes water or organic solvent liquids of polymer compounds, aqueous pigment dispersions, colloidal solutions, and the like. Further, the physical properties of the coating liquid are not particularly limited, but as conditions for the liquid applied onto the web, a lower viscosity is suitable;
ps or less, particularly 50 cps or less, is suitable. Although the surface tension is not particularly limited, preferable results can be obtained with a surface tension of 50 dyne/cm or less.

In the present invention, the web refers to paper, plastic film,
Includes resin coated paper, aluminum web, synthetic paper, etc. The material of the plastic film is, for example, polyolefin such as polyethylene or polypropylene,
Vinyl polymers such as polyvinyl acetate, polyvinyl chloride and polystyrene, polyamides such as 6.6-nylon and 6-nylon, polyethylene terephthalate and polyethylene-2
Polyesters such as 6-naphthalate, polycarbonates, cellulose acetates such as cellulose triacetate, cellulose diacetate, etc. are used. Further, the resin used for resin coated paper is typically polyolefin such as polyethylene, but is not necessarily limited thereto.

〔Example〕

Examples will be given in order to make the effects of the present invention more clear.

Example-1 A coating liquid having the composition and physical properties shown in Table 1 was applied to the surface of a polyethylene terephthalate film having a thickness of 200 μl, 10,000 mm using a coating device as shown in FIG. The coating liquid discharged from the liquid discharge port of the slot of the extrusion type coater 4 that protrudes overflows without forming crosslinks (method 1: any means may be used), and at a coating speed of 50 m/
sin, applied at 40cc/nf. At this time, the cutting air is applied from the thin tube nozzle 5 at a speed of 3.5 m/sec at the tip of the lip.
It was ejected onto both ends of the web at a wind speed of c. A thin tube nozzle with an inner diameter of 1.5 mm was used. At this time, the coating could be applied without any coating liquid adhering to the web edge.

In addition, at this time, the thin tube nozzle position was set so that the uncoated width at the edge of the web was 0.5 m, and no post-treatment was performed, and the coating film was spread to the edge of the web using only the natural leveling effect. was able to form.

Table 1 Comparative Example-1 When the coating liquid was applied under the same conditions as in Example-1, but with the air from the capillary nozzle stopped, the back amplifier on the back side of the web edge 7 appeared on the web edge as shown in Figure 5. The coating liquid adhered to the roller 3, causing stains 15.

〔Effect of the invention〕

As explained above, even when the coater slot width is larger than the web width, the coating device of the present invention can prevent the coating liquid from adhering to the web edges and rollers, and can be used for production using the thick coating section at the web end. It has become possible to perform coating with high efficiency and yield without any decrease in efficiency or product quality.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view (a
) and a side view (bl, FIG. 2 is a side view of another embodiment of the coating device of the present invention, similar to FIG. A perspective view (a) and a side view of an embodiment of a coating device equipped with a thin tube nozzle and a slit nozzle that spreads the coating to the end of the web. FIG. 5 is a perspective view of one embodiment of a coating apparatus having a position control device corresponding to a web edge, and FIG. 5 is a perspective view showing a coating situation in FIG. 1 when the capillary nozzle is not used. 1... Web 2... Coating film web 3... Backup roller 4... Extrusion type coater 5... Thin tube nozzle 6... Piping 7... Web edge 8... Coater lip surface 9 ...Edgeposisilane detector IO...Connection arm 11... -Driver 12...Guide rail 13...Slit nozzle 14...Gas piping 15...Dirty Figure 1 Figure Procedure main document August 29, 1999

Claims (1)

[Claims] In a coating device that supplies a coating liquid from a slot onto the surface of a continuously running support, a 0.1 to 2 m
Applying gas to a capillary nozzle that blows out gas to a coating liquid bridge formed between the support and the liquid discharge port of the slot so as to create an uncoated area of m, and to an uncoated area at the end of the support. A coating device characterized by being provided with a slit nozzle that pushes and spreads the coating liquid at the end of the coating film from the inside to the outside of the surface.