JP2005169305A - Coating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple device which can perform high-quality coating even when a very thin film with a large sag is used. <P>SOLUTION: After stretched between an IN-side support roll 4 and an OUT-side support roll 5 under the guidance of a guide roll 2, a film 1 is wound up. At the upstream side of the IN-side support roll 4, a bend bar 3 is installed with an adjustable contact depth and eliminates sag in the vicinity of the center part. On a guide plate 7 installed near at the IN-side lateral face of a coating head 6, a contact member 8 is set so as to be movable along the IN-side slope of the coating head 6. The contact member 8 is adjusted to eliminate sag at both the ends of the film 1, thereby performing even coating. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus for applying a liquid material to a traveling film using a die, and more particularly to an application apparatus applicable to a film having a thickness of 1.5 to 5.0 μm.

  Many coating methods are known as a method of applying a coating solution to a film. In particular, the use of die coaters has increased in recent years because the coating solution is not exposed to air until just before coating, so there is little change in the coating solution, and it has excellent uniformity in the width direction and smoothness of the coated surface. ing. As a typical coating method using this die coater, a traveling film is supported by a pair of support rolls that are spaced apart from each other, and the die is pressed against the film surface at an intermediate portion thereof, from the slit portion of the die. A method of extruding a coating solution and continuously coating the film is known.

Conventionally, most films as a support have a thickness of 5 μm or more, and those having good surface smoothness are used. For this reason, as a means for uniformly applying the coating liquid, contrivances on the coating side, such as the coating liquid coating uniformity and the uniformity of the gap between the film and the die, have been mainly made.
However, in recent years, the film has been made extremely thin for cost reduction, and the film width tends to be wider. Therefore, the necessity of high-quality application to an ultrathin film has arisen.
In fact, when applying an ultra-thin film using the conventional coating method, if there is slack in the coating part, the film sagging will occur in the coating liquid reservoir formed between the die tip and the film during coating. It has been found that air entrainment occurs due to the passage of the portion, the liquid reservoir portion is partially broken, and application lines and unevenness occur.

Therefore, in general, there is a method of maintaining a film mirror surface in the coating portion by providing a member for extending the slack such as an expander roll or a wrinkle removing roll on the upstream side of the coating portion (for example, patents). See references 1 and 2). However, both methods are designed to release the slack from the central part of the base material toward both ends, and in the case of a weak thin film, the mirror surface of the central part of the base material can be maintained. The problem that slack remains is generated. Alternatively, a method of eliminating the ripple phenomenon by adjusting the incident angle of the base film with respect to the coating head has been proposed (see, for example, Patent Document 3). However, in this method, the incident angle must be adjusted each time according to the characteristics of the base film.
As a device for solving these problems, Japanese Patent Application No. 2002-197182 of the present applicant and the like presents an example in which a contact portion that contacts the entire width is provided immediately before the die coating portion. However, in this example, there is an effect with respect to local film sagging, but when the linearity of the contact portion of the member is poor, the film cannot be contacted at the concave portion of the contact member, and rather sagging occurs, resulting in uneven gradation of coating. It has been found that a problem occurs. As a cause of poor linearity of the contact part,
・ Processing accuracy of the contacted member,
・ Deformation caused by temperature change of the member due to environmental temperature and latent heat of evaporation of coating liquid
It is difficult to maintain linearity as the width increases.

Japanese Patent Laid-Open No. 6-254466 (2nd page, FIGS. 1 and 15) Japanese Patent Laid-Open No. 11-333360 (pages 2, 3 and 1) JP 11-319677 A (page 4, FIG. 5)

  The problem to be solved is to provide a simple apparatus capable of high-quality coating even when using an extremely thin film having a large slackness.

The invention according to claim 1 includes a die having a slit portion for extruding the coating liquid, an IN side support roll and an OUT side support roll arranged at predetermined intervals on both sides of the die, and the slit portion. In the coating apparatus that continuously applies the coating liquid to a traveling film by extruding the coating liquid, the coating apparatus includes a mechanism that extends a sag in a region including a central portion of the film on the upstream side of the die with respect to the film traveling direction. It is characterized in that a contact portion is provided in contact with the vicinity of both end portions of the film immediately before entering the slit portion.
According to a second aspect of the present invention, in the coating apparatus according to the first aspect, the mechanism for extending the sag is a bend bar.
According to a third aspect of the present invention, in the coating apparatus according to the first aspect, the mechanism for extending the sag is a crown roll.
According to a fourth aspect of the present invention, in the coating apparatus according to any one of the first to third aspects, the mechanism for extending the slack is configured such that a contact depth with the film can be adjusted. Features.

According to a fifth aspect of the present invention, in the coating apparatus according to any one of the first to fourth aspects, the mechanism for extending the sag is provided on the opposite side of the film to the side where the coating liquid is applied. It is characterized by that.
According to a sixth aspect of the present invention, in the coating apparatus according to any one of the first to fifth aspects, the mechanism for extending the sag is provided further upstream than the IN-side support roll. .
According to a seventh aspect of the present invention, in the coating apparatus according to any one of the first to sixth aspects, the contact portion is configured to be capable of adjusting an incident angle at which the film is incident on the slit portion. In the invention according to claim 8, the coating apparatus according to any one of claims 1 to 6, wherein the film does not contact the die and is within a coating thickness. And a film coating method in which the light is incident on the upper surface of the die substantially in parallel with the gap.
The invention according to claim 9 is the film coating method according to claim 8, wherein the film is a master film for stencil printing.

  According to the present invention, wrinkles and sagging of a film substrate can be eliminated with a relatively simple device, and a desired coating liquid can be applied in a mirror state.

  The main part of the present invention is that in a coating apparatus provided with a coating head for extruding a coating liquid between two support rolls arranged at a predetermined interval, a predetermined amount of a bend bar is provided upstream from the IN-side support roll. The contact member is adjusted so that the contact depth is adjusted and contacted, and the contact member that contacts both ends of the film is provided in the vicinity of the IN side edge of the coating head. It is configured to be incident on the upper surface of the die almost in parallel with a gap within the coating thickness.

FIG. 1 is a partial cross-sectional side view for explaining a first embodiment of the present invention.
In the figure, reference numeral 1 is a film-like substrate, 2 is a guide roll, 3 is a bend bar as a mechanism for extending slack, 4 is an IN side support roll, 5 is an OUT side support roll, 6 is a die, 7 is a guide plate, 8 Indicates a contact member, and 9 indicates a micrometer head.
The film 1 is conveyed via a guide roll 2, an IN side support roll 4, and an OUT side support roll 5. The guide roll 2, the IN side support roll 4, and the OUT side support roll are all free rolls that are not driven.
The die 6 is a coating head longer than the width of the film-like substrate 1 (hereinafter simply referred to as the film 1), and is installed between two support rolls. A coating liquid is supplied from a liquid supply tank (not shown) by a gear pump (not shown). Is supplied, and the coating liquid is discharged from the slit-shaped coating part 6a. The upper surface 6e of the die 6 is formed in a plane having a slight width with the slit portion 6a as the center. A guide plate 7 is fixed to the IN side surface 6b of the die 6 with screws, and a micrometer head 9 is fixed to the guide plate. A contact member 8 is attached to the tip of the micrometer head 9. The contact portion of the contact member 8 is formed using a material having a small friction coefficient, and is disposed in parallel with the longitudinal direction of the application portion 6 a of the die 6. The contact member 8 can be vertically adjusted by sliding the IN side inclined portion 6 c of the die 6. The units of the contact member 8 are installed at two locations in the longitudinal direction of the die 6.

FIG. 2 is a diagram of adjusting the holding angle of the bend bar.
FIG. 3 is a schematic view when the slack is released to both ends.
The bend bar 3 is installed between the guide roll 2 and the IN-side support roll 4 so that the rotation axis is substantially parallel to the film 1, and the contact depth with the film 1 is changed by rotating in the direction of arrow A, The so-called hugging angle can be changed. The contact depth as used herein refers to the amount that the central portion protrudes from the straight line connecting both ends in the width direction of the film.
The bend bar 3 has a friction coefficient as small as possible by, for example, mirror-finishing a metal member so as not to give resistance to the running of the film 1.
While the film 1 is being conveyed to the IN-side support roll 4 through the guide roll 2, the center slack is released to both ends by the bend bar 3, the center is in a mirror state, and slack remains only at both ends. It becomes. At this time, the sag width at both ends is determined by the contact angle of the bend bar 3 with respect to the film 1. The contact angle referred to here is a rotation angle of the bend bar 3 from an angle at which the bend bar 3 contacts the film 1 for the first time. In experiments in the range of film thickness of 1.5 μm to 3 μm and film width of 400 to 1200 mm, it was found that the width of the slack portion at both ends can be suppressed within 100 mm by adjusting the contact angle. Thus, the slack width at both ends of the film 1 is adjusted to within 100 mm by adjusting the contact angle of the bend bar. Next, the film 1 comes into contact with the contact member 8 installed immediately before the application part of the die 6.
In FIG. 1, the contact position of the bend bar 3 with the film 1 is provided on the side opposite to the coating surface, but the same effect can be obtained even in principle on the same side as the coating surface. The bend bar 3 is provided on the upstream side of the IN-side support roll 4, but even if it is provided on the downstream side of the IN-side support roll 4, the same effect can be obtained as long as it is upstream of the contact member 8.

FIG. 4 is a view showing different embodiments of the mechanism for extending the slack.
In the figure, reference numeral 10 denotes a crown roll as a mechanism for extending slack.
The crown roll 10 is formed such that the diameter at the center is larger than the diameter at both ends, and the surface becomes a gentle convex surface when sectioned in the longitudinal direction. Both end portions have shaft portions that are held by bearings (not shown), and are configured to be rotatable in conjunction with film travel. Furthermore, both ends are configured to move together with the bearing in the direction of the arrow B so that the depth at which the crown roll surface contacts the film surface can be changed.
With this configuration, a slack of a certain width including the central portion of the film is eliminated. The width can be changed to some extent depending on the contact depth. Therefore, the crown roll 10 has the same effect as the bend bar 3.

FIG. 5 is a partial view showing the relationship between the contact position with the film and the coating portion. 4A shows the case where the film enters from above, FIG. 3B shows the case where the film enters from below and contacts the edge on the IN side of the die 6, and FIG. Each of the cases where the light is incident on the gap within the coating liquid thickness without contacting the side edge is shown.
The width of the both-end contact member 8 is 120 mm so as to cover the sagging width of both ends of the film 1, and is set from the outside of the film end surface by 10 mm. Further, since the angle at which the film enters the coating portion, that is, the incident angle changes depending on the film contact position of the contact portion 8, the position adjustment of the contact member 8 is necessary so that the incident angle is optimized. This position adjustment is performed by the micrometer head 9 attached to the IN side inclined portion 6 c of the die 6.

As shown in FIG. 5A, when the film 1 is incident from above the application portion 6a, air is entrained simultaneously with the application of the paint, and unevenness and streaks are formed in the coating film.
As shown in FIG. 4B, when the film 1 is incident from below and the entire width of the film contacts the edge 6d on the IN side of the die 6, the flatness of the film depends on the linearity of the edge 6d on the die IN side, The effects of the bend bar 3 and the contact member 8 cannot be exhibited.
As shown in FIG. 5C, when the film 1 does not contact the die IN side edge 6d and is incident on the upper surface 6e of the die almost in parallel with a gap within the coating thickness, the mirror surface state extends over the entire width of the film. As a result, the effects of the bend bar 3 and the contact member 8 are maximized. The contact member position that creates such a film incident angle is the optimum position. That is, when the slack portions at both ends of the film 1 come into contact with the contact members 8 at both ends adjusted to the optimum positions, the slack at both ends of the film is extended and a mirror surface state is obtained over the entire width of the film. The coating unit 6a is applied in this mirror state and a good coating state is obtained, and the coated film 1 is conveyed to a drying unit (not shown) via the OUT side support roll 5.

The application example which manufactures the porous body film used for the printing master for stencils below is shown.
Substrate used ――― PET film 1.5-3μm thick Used coating solution ――― W / O emulsion solution.
91 wt% ethyl acetate as the oil phase
Acetal resin 5 wt%
4 wt% pigment solution and
99 wt% water as water phase
Cellulose resin 1 wt% solution
Are mixed at a ratio of 1: 1, and an appropriate activator is added thereto,
Emulsified with propeller stirring for 3 hours.
Coating thickness ――― 35μm (Wet)
As a result of applying by the method shown in FIG. 5C using the above-mentioned base material and coating solution, it was possible to apply without sagging film, and high quality coating quality was obtained.

It is a figure for demonstrating the 1st Embodiment of this invention. It is a figure of the holding angle adjustment of a bend bar. It is a schematic diagram when slack is escaped to both ends. It is a figure which shows the Example from which the mechanism which extends a slack differs. It is the figure which showed the relationship between a contact position with a film, and an application part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film 2 Guide roll 3 Bend bar 4 IN side support roll 5 OUT side support roll 6 Die 8 Contact member 10 Crown roll

Claims (9)

  A die having a slit portion for extruding the coating liquid, and an IN side support roll and an OUT side support roll disposed on both sides of the die at a predetermined interval, and the coating liquid is pushed out from the slit portion to travel. In the coating apparatus for continuously applying to the film, the coating apparatus includes a mechanism that extends a sag in a region including a central portion of the film upstream of the die with respect to the film running direction, A coating apparatus comprising a contact portion that makes contact in the vicinity of both ends.   The coating apparatus according to claim 1, wherein the mechanism for extending the sag is a bend bar.   The coating apparatus according to claim 1, wherein the mechanism for extending the sag is a crown roll.   4. The coating apparatus according to claim 1, wherein the mechanism for extending the sag is configured such that a contact depth with the film can be adjusted.   5. The coating apparatus according to claim 1, wherein the mechanism for extending the sag is provided on a side opposite to a side on which the coating liquid is applied to the film.   6. The coating apparatus according to claim 1, wherein the mechanism for extending the sag is provided further on the upstream side than the IN-side support roll.   7. The coating apparatus according to claim 1, wherein the contact portion is configured to be capable of adjusting an incident angle at which the film is incident on the slit portion.   The coating apparatus according to any one of claims 1 to 6, wherein the film does not contact the die and is incident on the upper surface of the die substantially in parallel with a gap within a coating thickness. A characteristic film coating method. 9. The film coating method according to claim 8, wherein the film is a master film for stencil printing.

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