JPH07185436A - Duplex coating device and grooved roller used on same device - Google Patents

Abstract

PURPOSE:To make a conventional broad one surface coating method applicable as a duple:x coating method and thereby eliminate the limits to application of the duplex coating method by providing a first and a second coating parts, and a grooved roller which the rotates in an oppsite direction to a direction in which the uroller runs, supporting a base material by a first face coming into contact with the base material against the second coating part. CONSTITUTION:A base material l supplied to a coating unit is guided by a back-up roller 3, a twisting roller 8 and a grooved roller 5, and then is guided to a next dryer from the coating unit. The back-up roller 3, supporting the base material 1 in a freely running fashion, is instal.led against a first die head 2, and acts to keep a constant distance between the first die head 2 and the base material l. In addition, the grooved roller 5 also supports the base material l in a freely running manner and is installed against 4 second die head. Further, the grooved roller 5 acts to keep a constant distance between the second die head 4 and the base material 1, and is rotated in an opposite direction to a direction in which the base material 1 runs. Thus, the satisfactory coating of the first face of the base material 1 is ensured.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a coating apparatus. In particular, the present invention relates to a double-sided coating device for double-sided coating of a liquid coating material on a long sheet such as a plastic film, paper, rolled steel plate, cloth, non-woven fabric, and composite material sheet, and a grooved roller used for the same.

[0002]

2. Description of the Related Art Conventionally, an apparatus as described below has been known as a double-sided coating apparatus. (1) Dip coating device As shown in FIG. 5 (A), this is a device for applying a base material by immersing it in a coating liquid and then pulling it up. According to this device, if it is desired to increase the line speed in order to increase productivity, it is necessary to lower the viscosity of the coating liquid, but the relationship between the viscosity of the coating liquid, the line speed and the coating film thickness is It is difficult to control the film thickness because there is no method other than obtaining it by experiment. Further, considering the uniformity and surface property of the formed coating film, the range of selection of coating conditions is small. In addition, it is necessary to reduce the viscosity in order to increase the speed, but it is difficult to dramatically increase the speed because there is a limit to dilution.

(2) Overflow coating device As shown in FIG. 5 (B), this is a device for transporting a substrate in a vertical type and for applying a coating liquid from above the substrate. According to this apparatus, since the base material is a vertical type, dripping due to gravity causes a large difference in coating film thickness in the width direction of the base material. In addition, speeding up is difficult.

(3) Single-sided sequential coating device As shown in FIG. 5 (C), the base material is coated on one side by a roller and a coating section to dry and solidify the coating film, and then the opposite surface of the base material. In the same manner as above, one side is applied, the coating film is dried and solidified, and both sides are applied. According to this apparatus, two coating units and two drying apparatuses are required, which is disadvantageous in terms of apparatus cost, and the operability deteriorates because the distance between both units becomes long. Further, since one side passes through the drying device once and the other side passes twice, the characteristics of the coating films on both sides do not exactly match and a slight difference occurs.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the conventional double-sided coating apparatus, and the coating film thickness is uniform in each surface and both side surfaces, and the surface of the coating film is It has excellent surface properties without defects, and can be coated at high speed with good productivity.
An object of the present invention is to provide a coating apparatus that is compact and has good operability. In addition, many single-sided coating methods have been known in the past, and a wide selection could be made even if there were restrictions such as the type of base material and coating liquid and coating conditions. There were few methods and the selection range was small. In particular, an object of the present invention is to provide a double-sided coating device and a grooved roller used for the same that can apply a wide range of conventional single-sided coating methods to double-sided coating methods and eliminate the restrictions of the conventional double-sided coating methods. is there.

[0006]

The above object can be achieved by the present invention described below. That is, (claim 1) a first coating part for coating a first surface of a base material and a second coating portion for coating a second surface of the base material, which is the opposite surface to the first surface. A coating section and a grooved roller that is installed so as to face the second coating section and that supports the base material in contact with the first surface and that rotates in a direction opposite to the traveling direction of the base material. Double-sided coating equipment. (Claim 2) A grooved roller used in a double-sided coating device, wherein the groove pitch is 0.3 mm ≤ A ≤ A
A grooved roller characterized in that the groove depth B is 1.0 mm, the groove depth B is B ≦ 200 μm, and the ratio of the groove pitch A to the bank length C is 2 ≦ A / C ≦ 5.

[0007]

With the first coating section, the first surface of the base material can be coated, and the second coating section is provided with a groove that rotates in the direction opposite to the traveling direction of the base material. Rollers are installed,
Since the base material coated by the first coating unit is contact-supported on the first surface by the grooved roller, even if the base material is vibrated by the hot air of the dryer or the base material is deformed, The coating can be performed by the coating section, and the grooved roller can satisfactorily form the coating film on the first coating surface, which enables high-precision double-sided coating.
Also, a grooved roller used in a double-sided coating device,
As the groove shape, the groove pitch A is 0.3 mm ≦ A ≦ 1.0 m
m, the groove depth B is B ≦ 200 μm, the ratio of the groove pitch A to the bank length C is 2 ≦ A / C ≦ 5. The back side coating accuracy is good, the coating liquid does not stay in the groove, the back side coating accuracy is good, and a good coating film on both sides can be obtained.

[0008]

The present invention will be described below based on the preferred embodiments. FIG. 1 is a diagram showing a configuration of a coating unit of a double-sided coating device of the present invention. In the figure, 1 is a substrate, 2 is a first die head, 3 is a backup roller, 4 is a second die head, 5 is a grooved roller, 6 is a pump for supplying the coating liquid to the first die head, and 7 is A pump for supplying the coating liquid to the second die head, and 8 is a twist roller.

The operation of the coating unit having the above structure will be described. Substrate 1 supplied to coating unit
Is guided by the backup roller 3, the twist roller 8, and the grooved roller 5, and is guided from the coating unit to the next dryer. The backup roller 3 movably supports the base material 1, is installed to face the first die head 2, and plays a role of maintaining a constant gap between the first die head 2 and the base material 1. In addition, the grooved roller 5 also supports the base material 1 so that it can travel freely and is installed so as to face the second die head 2, and serves to keep the gap between the first die head 2 and the base material 1 constant.

The clearances can be finely adjusted in units of 1.0 μm by a position adjusting mechanism (not shown) which is usually located at the left and right positions of the first and second die heads. The adjustment width is about 1 mm. When the coating is stopped, the die head is moved to a standby position by a moving mechanism (not shown) in order to pass the base material 1 from the feeder of the coating device to the winder and to clean the die head and rollers. It is possible. Further, the die head can be removed from the moving mechanism, and an appropriate type of die head can be selected and replaced depending on the coating conditions.

The coating liquid is supplied from the storage tank for the coating liquid to the die head by the coating liquid supply pumps 6 and 7. The storage tank for the coating liquid is equipped with auxiliary devices such as stirring the coating liquid to make it uniform at all times, and performing final filtration before supplying. In addition, the coating liquid supply pump is equipped with a pressure control valve that can adjust the supply pressure of the coating liquid from the outside, a valve that stops the supply of the coating liquid, a circulation system pipeline, and auxiliary devices such as a flow control device. . Further, the structure is such that hot water can be flowed inside the die head to adjust the temperature.

One of the features of the coating liquid supply system including the storage tank and the coating liquid supply pump is that the entire system is a closed system, and foreign matter such as dust from the outside is mixed,
Alternatively, it is completely protected from the scattering of volatile components of the coating liquid to the outside. Therefore, the coating liquid can keep the desired composition pure until the substrate 1 is coated by the die head. This is extremely important for obtaining a good quality coating film.

The coating liquid supplied to the die head through the pipeline by the coating liquid supply pump fills the coating liquid chamber in the die head and passes through a slit having a width that fills the width of the substrate 1 provided in the die head. Coating is performed by flowing out to the base material 1 so that it exudes due to the pressure of the coating liquid. The die head may be attached with an outflow amount adjusting mechanism (not shown) for adjusting the outflow amount of the coating liquid. Normally, the outflow control mechanism is
This is a method in which the gap between the slits is adjusted, and is configured so that it can be adjusted independently at a plurality of positions in the width direction of the base material 1. Therefore, the coating liquid cannot be supplied to both ends of the base material, and the coating film thickness can be adjusted to be uniformly formed in the other portions. A coating width adjustment mechanism is attached to the die head. Normally, the adjusting mechanism can be adjusted to an arbitrary width by inserting a block-shaped pocket plug in the gap between the manifold and the slit and sliding it.

During normal operation, the coating amount is adjusted by adjusting the slit of the die head and the pressure of the coating liquid.
The physical properties and composition of the coating liquid, such as viscosity, are not changed. When the traveling speed of the substrate 1 changes, these conditions are adjusted so that the coating amount falls within a predetermined range.

The first die head 2 applies the coating to the first surface of the substrate 1, and the second die head 4 applies the coating.
Coating is applied to the second surface of the base material 1 which is the surface opposite to the first surface. The coating liquid applied to the second surface of the base material 1 does not come into contact with anything other than air as it is, and enters the dryer to be dried. On the other hand, coated on the first surface of the substrate 1,
The coating liquid comes into contact with the grooved roller 5.

As described above, one of the roles of the grooved roller 5 is installed so as to oppose the second die head 4 and supports the base material 1 so that it can run freely. It is to keep the gap between the materials at a predetermined value. Another role of the grooved roller 5 is to fulfill the above-mentioned role and at the same time to form a good coating film on the first surface of the substrate 1.

In order to support the base material 1 so that it can travel freely by means of rollers, a method is usually used in which the rollers are rotated with the traveling base material (forward rotation). Also in the double-sided coating apparatus of the present invention, this method is performed in the first die head. However, when the method is applied to the second die head, the coating property of the first surface of the base material 1 is significantly deteriorated, and defects such as uneven thickness, satin, rubbing and peeling occur. . One of the features of the double-sided coating device of the present invention is that the grooved roller 5 is rotated in the opposite direction to the traveling direction of the base material 1, so that the coating film on the first surface of the base material 1 is well formed. It is about tightening.

By means of the grooved roller 5, the first of the substrate 1 is
The details of the reason why the coating film on the surface can be well formed are unknown. However, it is presumed that the reason is as follows. First, when a roller having no groove in a dry state is rotated in the opposite direction to the traveling direction of the base material 1 without coating the first surface of the base material 1, friction due to contact between the base material and the roller is generated. Then, abnormal vibration occurs in the base material and the roller, which not only deteriorates the surface property of the coating film on the second surface, but also
The base material and rollers are damaged by friction.

When the first surface of the base material 1 is coated and a roller having no groove is rotated in the opposite direction to the running direction of the base material 1 while being wet with the coating liquid, the above-mentioned drying is performed. Although it is less than the state, abnormal vibration still occurs on the base material and the roller. In addition, the formed coating film has poor surface properties and defects are observed. On the other hand, when the grooved roller is rotated in the opposite direction to the running direction of the base material 1 in the state where the first surface of the base material 1 is coated and wet with the coating liquid, In addition, it can play the role of a lubricant sufficiently, and because the intervals and gaps of the grooves are uniform, and because of the reverse rotation, the uniformity of the entire coating surface of the coating film is also obtained. It seems to be done.

Next, regarding the twisting roller, the twisting roller 8 has a function that can be corrected by appropriately contacting the twisting roller 8 with the base material when the base material has an extreme slack. is there. The twist roller 8 also has a function of changing the winding angle of the base material around the grooved roller depending on the thickness of the base material and adjusting the optimum coating condition.

A modification of the coating unit of the present invention is shown in FIG. In FIG. 2, (A) is a diagram showing an example in which a roll is used for the coating part. Such a roll may be either forward coating in which the running direction of the base material and the direction of the rotating peripheral surface of the roll coincide, or reverse coating in the opposite direction. Also,
The number of rolls, the type of roll (metal roll, rubber roll, gravure roll, etc.) and roll arrangement can be used in an appropriate form as required.

FIG. 2B is a diagram showing an example in which a blade is used for the coating part. FIG. 2 shows a coating unit of the present invention in which a trailing blade coater is modified, but other blade coaters, for example, a flexible blade coater.
ater), flooded bladecoa
The coating unit of the present invention can be configured by a modification such as ter). As described above, the conventional single-sided coating method can be modified to form the coating unit of the present invention.

Now, the description of the coating unit of the double-sided coating apparatus of the present invention is completed, and then the grooved roller 5 will be described in more detail. FIG. 3 shows a grooved roller that can be used in the present invention. As shown in FIG. 3, in the grooved roller 5, the grooves are formed substantially parallel to the circumferential direction of the roller. Each groove is independent,
It may be a groove that goes around the circumference of the roller and returns to the original,
Further, it may have a spiral shape.

Further, the groove may have a shape obtained by cutting the peripheral surface of the roller by cutting or the like, and in that case, the cross-sectional shape may be semicircular, triangular, trapezoidal or the like. Alternatively, a wire made of stainless steel or the like may be wound around the peripheral surface of the roller. However, since the die coating is performed in a face-to-face manner, high precision is required, and among them, a high precision roller having grooves formed therein is preferable. Further, it is preferable to leave the bank portion as much as possible in order to maintain accuracy.

The cross-sectional area of the groove, the pitch, and the reverse rotation speed are also not particularly limited. However, the viscosity characteristics of the coating liquid,
A good coating film can be obtained by making various selections depending on the drying characteristics of the coating liquid, the physical properties of the substrate (ease of wettability, permeability, etc.), the traveling speed of the substrate, and the like.

Among various selections, the groove pitch of the grooved roll, the groove depth B, and the groove depth of the grooved roll, which can be used for general purposes and can obtain a good coating film,
It is to properly select the three parameters of the bank length C. Preferably, the groove pitch A is 0.3 mm ≦ A ≦ 1.
0 mm is good. When 1.0 mm ≦ A, the base material is likely to be scratched and streaks corresponding to the groove pitch appear on the coated surface after passing through the grooved roll. Further, when A ≦ 0.3 mm, the groove depth may be non-uniform due to processing accuracy problems, and the bank length cannot be made long, so that the back surface coating accuracy deteriorates.

Preferably, the groove depth B is B ≦ 200 μm. When 200 μm ≦ B, it is difficult to exchange the coating liquid inside the groove and it takes a long time for cleaning. The groove depth B can be reduced to the extent that there is no problem in processing accuracy. Also, bank length C
Is preferably as long as possible in view of the accuracy of the back surface coating, but not so long in view of scratches due to liquid wetting and friction between the grooved roll and the substrate. The ratio of the groove pitch A to the bank length C is preferably 2 ≦ A / C ≦ 5.

For example, in order to obtain a coating film thickness of 100 μm (in a wet state), the following conditions apply to the grooved roller 5. Groove shape: V-shaped, pitch 0.5 mm, depth 140 μm,
Bank length 0.1 mm Reverse rotation speed: Almost equal to line speed Base material holding angle: 30 °

Next, the overall structure of the double-sided coating device of the present invention will be described. FIG. 4 is a diagram showing an example of the overall configuration of the double-sided coating device of the present invention. In FIG. 4, 9 is a substrate feeder, 10 is a feed roll, 11 is a dancer roll, 12 is a coating unit, 13 is a pre-dryer, 14 is a turn roller, 15 is a post-dryer, 16 is a drive roller, 17 Is a winder.

In the above structure, the feeder 9 is a turn arm type feeder and holds two windings of the base material. When the winding of one of the substrates is near the end, it is possible to switch to the other winding. A base material storage device is provided downstream of the feeder 9, and the feeder 9 side can be temporarily stopped while coating is continued for the time period required to connect the newly wound base material and the old wound base material. .

The feed roller 10 feeds the base material to the coating unit 12, applies proper tension to the base material between the feed roller 10 and the drive roller 16, and prevents the base material from loosening. The dancer roller 11 detects the tension of the substrate and the slack of the substrate. The base material coated by the coating unit 12 is dried by the predryer 13 until the coating liquid does not adhere to the rollers. The base material folded back by the turn roller 14 is dried by the post-dryer 15 to the required degree of drying. The base material after drying is drive roller 1
After 6 it is taken up by a winder.

Next, the base material and the coating liquid which can be coated with the coating apparatus of the present invention will be described. The base material is not particularly limited, and examples thereof include plastics such as polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyvinyl chloride, polystyrene, nylon, polyimide, polyvinylidene chloride, polyvinyl alcohol, fluororesin, chlorinated rubber, and ionomer. Examples thereof include films, condenser paper, paper such as paraffin paper, non-woven fabric, and cloth.

Metal sheets such as rolled steel plate, aluminum foil, and copper foil are also suitable, and may be a composite material of various materials regardless of nonmetal or metal. Even a strong substrate such as an iron plate can be straightened by a twist roller, backup roller, grooved roller, etc., and the winding angle around the grooved roller can be set appropriately according to the characteristics of the material. Therefore, the coating apparatus of the present invention can be applied to a wide range of substrates.

The coating liquid is not particularly limited, and for example,
Pigments such as coloring materials, magnetic materials, conductive materials, vehicles made of various polymer materials, coating solutions mainly composed of dissolved solutions such as organic solvents, and solvent-free coating solutions such as wax and thermoplastic resins Alternatively, a reactive coating liquid containing a crosslinking agent or the like may be used.

Further, it can be suitably applied to coating liquids such as adhesives, emulsions and photoresists. For example,
Examples of photoresists are casein, gelatin, gum arabic, fish gurus, shellac, egg white, PV
A coating solution for a water-soluble colloidal photoresist, which is obtained by adding dichromate ions or the like to an organic hydrophilic colloid aqueous solution such as A. A coating solution such as a cyclic rubber-based (aromatic viazide-based) photoresist or a novolac-based (quinone / diazide-based) photoresist can also be excellently coated by the coating apparatus of the present invention.

The present invention has been described above with reference to the examples, but the present invention is not limited to the examples, and the present invention is not limited to the embodiments and various embodiments to which the gist and technical idea of the present invention are applied. It is needless to say that the present invention can be carried out and they are also included in the present invention. For example, in the embodiment, the configuration in which the winding of the base material can be exchanged while stopped is shown, but the configuration may be such that the base material is automatically connected while the base material is running. It may be configured to. After coating and drying, do not wind the coated substrate,
It can also be connected inline with the subsequent process.

[0037]

As described above, according to the coating apparatus of the present invention, since the coating liquid is circulated and coated in a closed system, foreign matter may be mixed into the coating liquid and gelation may occur. The quality of the coated film is eliminated. In addition, since the grooved roller is used as a backup roller when coating the second surface, double-sided coating can be performed, the coated surface is highly accurate, and the application range of the coating liquid and the base material is extremely wide. Is. Furthermore, the coating liquid may have a high viscosity, and the drying efficiency can be improved, high-speed running is possible, and productivity is high. Further, in the grooved roller used for the double-sided coating device, it can be used for general purposes, the base material is not easily scratched, the back surface coating accuracy is good, the coating liquid does not stay in the groove, and the back surface coating accuracy is high. Good coating films can be obtained on both sides.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a coating unit of a double-sided coating device of the present invention.

FIG. 2 is a diagram showing another configuration of the coating unit of the double-sided coating device of the present invention.

FIG. 3 shows a grooved roller that can be used in the present invention.

FIG. 4 is a diagram showing an example of the overall configuration of a double-sided coating device of the present invention.

FIG. 5 is a view showing a conventional double-sided coating device. (A) Dip coating method (B) Overflow method (C) One-sided sequential coating method

[Explanation of symbols]

 1 Base Material 2 First Die Head 3 Backup Roller 4 Second Die Head 5 Grooved Roller 6 First Coating Liquid Supply Pump 7 Second Coating Liquid Supply Pump 8 Twist Roller 9 Feeder 10 Feed Roller 11 Dancer Roller 12 Coating unit 13 Front dryer 14 Turn roller 15 Post dryer 16 Drive roller 17 Winder

Claims (2)

[Claims] 1. A first coating section for coating a first surface of a base material, and a second coating section for coating a second surface of the base material, which is an opposite surface of the first surface. And a grooved roller that is installed so as to face the second coating section and that supports the base material in contact with the first surface and that rotates in a direction opposite to the traveling direction of the base material. A double-sided coating device characterized in that 2. A grooved roller used in a double-sided coating apparatus, wherein the groove shape has a groove pitch A of 0.3 mm ≦ A ≦.
A grooved roller characterized in that the groove depth B is 1.0 mm, the groove depth B is B ≦ 200 μm, and the ratio of the groove pitch A to the bank length C is 2 ≦ A / C ≦ 5.