KR20170136311A - Shim for the uniform coating distribution of non-Newtonian coating liquids in side slot die and Slot die coater including the same - Google Patents

Abstract

Disclosed are a shim within a slot die for uniformly distributing non-Newtonian coating solution, and a slot die coater comprising the same. According to the present invention, as a shim for being interposed between a first slot die and a second slot die facing each other, and for uniformly coating of non-Newtonian coating solution, the shim comprises: a coupling unit which comprises a through-hole in which a bolt is penetrated for coupling to the first slot die and the second slot die; a first extension unit which is extended from one side of the coupling unit in the longitudinal direction; a second extension unit which faces the first extension unit, and is extended from the other side of the coupling unit in the longitudinal direction; and a protruding unit which is located between the first extension unit and the second extension unit, and protrudes in the discharging direction of the coating solution on one surface of the coupling unit.

Description

[0001] The present invention relates to a shim in a slot die for uniform distribution of a non-Newtonian coating liquid and a slot die coater including the same,

The present invention relates to a core in a slot die for uniform distribution of a non-Newtonian coating fluid and a slot die coater including the same, and more particularly, to a slot die coater comprising a non-Newtonian coating fluid, And a slot die coater including the same.

Slot die coating is a typical process for producing a uniform coating film or film. By using slot die coating, continuous production at high speed is possible, and a uniform film can be produced in the width direction.

In the case of the solution (coating solution) used in the slot die coating, the product to be produced is being refined and upgraded to a complex oil system including simple oil systems, particles, colloids and polymers.

In the case of non-Newtonian, one of the representative features of complex systems, the viscosity of the fluid changes with shear rate. Viscosity is closely related to the operating speed of the process and the structure of the coater. Generally, at low shear strain rates, the viscosity is constant like Newtonian fluids, but when the shear strain rate is greater than a certain value, (Shear thinning).

However, in the suspension system, shear thickening behavior is observed with increase of particle concentration. Slot die coating, which does not take into account the rheological properties of the solution, can therefore lead to unstable and non-uniform coatings.

In general, the optimum design of the slot die considering the rheological properties of the coating liquid means the change of the structure of the die inner chamber and the slit, that is, the manifold structure.

When only fluids with specific rheological properties are used, the design of such die internal manifolds is meaningful and enables the production of uniform coating products. However, when a coating liquid having a rheological property changed is applied to the slot die, a uniform coating flow is not generally ensured, which is an economical burden to newly design an expensive slot die.

If the non-Newtonian property of the coating liquid is not reflected in a general slot die, the middle part in the coating width direction has a fast flow rate and the both ends have a slow flow rate distribution. Thus, the applied film has a thickness variation in the width direction. As a solution to this problem, slot die coaters of different shapes were designed and fabricated, or chamber blocks were inserted in consideration of rheological properties.

For example, U.S. Pat. No. 7,862,755 B2 produced a die similar to a hanger for uniform extrusion of polymeric materials with thermoplastic properties. In this case, the polymer material uniformly forms the polymer material by keeping the shear rate and residence time experienced inside the die uniformly. However, if the rheological properties of the binder and particles contained in the solution change depending on the content of the solvent and the solvent, a new die must be produced.

Korean Patent Laid-Open No. 10-2008-0097905 also discloses a technique of evenly distributing the mass in the transverse direction by inserting a transverse flow metering gap in the slot die. However, in this case, there is a possibility that the stagnation area is formed in the chamber due to the transverse flow metering gap, and there is a possibility that the coating property may be deteriorated due to the vortex that may occur and particle entanglement within the area.

In order to solve the problems of the prior art described above, the present invention proposes a method for uniformly distributing a non-Newtonian coating solution without changing the structure of an expensive slot die, And a slot die coater including the same.

According to an aspect of the present invention, there is provided a shim for uniform coating of a non-Newtonian coating liquid disposed between first slot die and second slot die opposed to each other, A coupling portion having a through-hole through which a bolt for coupling with the first slot die and the second slot die passes; A first extension extending longitudinally from one side of the coupling; A second extension portion facing the first extension portion and extending in the longitudinal direction at the other side of the engagement portion; And a concavo-convex portion located between the first extension portion and the second extension portion and protruding in a direction of discharging the coating liquid from one surface of the coupling portion.

The second slot die is formed with a chamber for storing the coating liquid injected through the coating liquid injecting portion, and the concave and convex portion may protrude in the coating liquid dispensing direction from the coating liquid injecting portion disposing region.

The concavo-convex portion may protrude from the central region of the chamber in the discharge direction of the coating liquid.

The concavo-convex portion may have a shape such that the width of the concavo-convex portion decreases in the discharge direction of the coating liquid in the chamber.

The concavities and convexities may be triangular.

The concavity and convexity protrudes in a depth direction, and the depth direction can be defined as a direction from the first slot die to the second slot die side.

Wherein the first extending portion includes a first upper extending portion extending from the coupling portion and a first lower extending portion extending from the first upper extending portion in the coating liquid discharging direction and the second extending portion extending from the coupling portion And a second lower extension portion extending in the coating liquid discharge direction at the second upper extension portion and the second upper extension portion, wherein a widthwise distance between the first upper side opposing portion and the second upper side opposing portion is a distance between a first lower opposing portion and a second lower opposing portion, 2 lower-side opposed portion in the width direction.

The first lower extension portion and the second lower extension portion may be formed parallel to each other.

According to another aspect of the present invention, there is provided a slot die coater for uniform coating of a non-Newtonian coating fluid, comprising: a first slot die; A second slot die disposed opposite the first slot die; And a shim disposed between the first slot die and the second slot die, wherein the shim includes a coupling portion having a through groove through which a bolt for coupling with the first slot die and the second slot die passes, A second extension extending in a longitudinal direction from the other side of the engagement portion and opposed to the first extension, and a second extension extending from the first extension and the second extension, And a concavo-convex portion protruding in a direction of discharging the coating liquid from one surface of the coupling portion.

 According to the present invention, since the non-Newtonian coating liquid can be uniformly coated only by changing the core structure, there is an advantage that the process cost is reduced.

In addition, according to the present invention, it is possible to improve the coating property by suppressing vortex formation which may occur in the chamber when the suspension is coated through modification of the core structure.

1 is a perspective view of a slot die coater according to the prior art.
2 is a view showing a shape of a shim disposed between two slot dies according to the prior art.
3 is a graph showing the physical properties of the coating liquid applied to the present embodiment.
FIG. 4 shows velocity distribution and velocity difference in a slot coating using shims according to the prior art.
5 is a view showing a configuration of a slot die coater according to a preferred embodiment of the present invention.
6 is a plan view of the shim according to the embodiment.
FIG. 7 is a view showing velocity distribution and velocity difference in slot coating using a shim according to an embodiment of the present invention. FIG.
8 is a graph showing a correlation between C _W and T _W and a power-law index in a slot coating using a shim according to the present embodiment.
9 to 10 are views showing a shape of a shim according to another embodiment of the present invention.
11 is a view showing a change in vortex phenomenon in a slot coating using a core shape according to an embodiment of the present invention.
12 is a view showing a shape in which the core is converging in the discharge direction of the coating liquid.
Fig. 13 is a view showing the velocity distribution in the discharge portion when the shim has a converging shape. Fig.
FIG. 14 is a view showing a shape in which the core is diverging in the discharge direction of the coating liquid. FIG.
Fig. 15 is a view showing the velocity distribution in the discharge portion when the shim has a shape diverging. Fig.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

The present invention modifies the shape of the shim disposed inside the slot die to uniformly coat the non-Newtonian coating liquid. For convenience of explanation, the conventional slot die and its core structure will be discussed first.

FIG. 1 is a perspective view of a slot die coater according to the related art, and FIG. 2 is a view showing a shape of a shim disposed between two slot dies according to the related art.

Referring to Figure 1, a slot die coater includes a first slot die (slot die top plate, 100) and a second slot die (slot die lower plate, 102).

The second slot die 102 is connected to an injection unit 104 through which a coating liquid is injected and a chamber 106 for storing the coating liquid injected through the injection unit 100 is formed.

A shim 108 is placed between the first slot die 100 and the second slot die 102. The shim 108 forms a slit for discharging the coating liquid stored in the chamber 106.

The flow of the coating liquid in the first and second slot dies 100 and 102 is determined in the chamber 106 and the shim 108 and the velocity uniformity in the width direction is determined according to each structure and size.

The object to which the coating liquid discharged in the slot die is applied is referred to as a web, a substrate, or a support layer. At this time, the line speed and the vacuum pressure are appropriately controlled according to the flow rate of the coating liquid to be discharged, so that a uniform coating film can be formed in the proceeding direction.

The applied film should have uniform coating properties in the direction of travel and width. Accordingly, not only should appropriate process control parameters be considered, but also an appropriate slot die should be constructed for the solution.

Conventional slot die coating utilizes a rectangular shape to avoid influencing the flow in the slot die in the case of the shim 108 because it contemplates the shape of the chamber 106 depending on the fluid properties of the coating solution.

When coating is carried out using a coating fluid having different rheological properties, the velocity distribution in the slot die may not be uniform in the width direction along the slot die.

The distribution in the slot die is shown in FIG. 4 when coating is carried out using the coating fluid of rheological properties as shown in the following Table 1 and FIG. FIG. 4 shows velocity distribution and velocity difference in a slot coating using shims according to the prior art.

Carreau model Solution

Relaxation time 0.815

power law index 0.4 to 0.6

zero shear viscocity 0.376

density 1143.5

FIG. 5 is a view showing a configuration of a slot die coater according to a preferred embodiment of the present invention, and FIG. 6 is a plan view of a shim according to the present embodiment.

5 to 6, the slot die coater according to the present embodiment includes a first slot die 500, a second slot die 502 and a first slot die 500 and a second slot die 502 (Not shown).

A bolt 506 penetrating the second slot die 502 and the shim 504 is inserted into the first slot die 500.

The second slot die 502 is formed with a chamber 508 for storing the coating liquid injected through the injection part 507. Here, the injection portion 507 is disposed in the central region of the chamber 508. [

The shim 504 according to the present embodiment includes a coupling portion 510 having a through hole 512 through which the bolt 506 penetrates and a coupling portion 510 extending from both sides of the coupling portion 510 in the longitudinal direction, And includes a first extending portion 520 and a second extending portion 530 extending downward. Here, the direction from the upper side to the lower side is defined as the flow direction of the non-Newtonian coating liquid.

Here, the first extending portion 520 and the second extending portion 530 are disposed opposite to each other.

According to one preferred embodiment of the present invention, a concave-convex portion 540 protruding in the coating liquid discharge direction is formed on one surface of the coupling portion 510.

Preferably, the concave-convex portion 540 protrudes in the dispensing direction of the coating liquid in the central region in the width direction of the engaging portion 510. [

Here, the central region in the width direction may be a region for arranging the coating liquid injecting portion 507 of the chamber 508.

The concavity and convexity 540 is formed in the coupling direction of the coating liquid, that is, in the longitudinal direction T _L Direction), and the width (T _W ) becomes smaller.

Preferably, the concave and convex portions 540 may be semicircular or triangular, and more preferably triangular.

The length T _L of the concave / convex portion 540 affects the central flow in the chamber 508, and the slit center injection portion 507 has to be determined at the blocking level.

According to an embodiment of the present invention, the first extending portion 520 and the second extending portion 530 of the shim 504 are formed to have different lengths between the upper side and the lower side.

More specifically, the first extension 520 includes a first upward facing portion 522 and a first downward facing portion 523, a second extending portion 530 includes a second upward facing portion 524, And a second lower opposing portion 525.

The distance in the width direction between the first upper side opposing portion 522 and the second upper side opposing portion 524 is smaller than the distance in the width direction between the first lower side opposing portion 523 and the second lower side opposing portion 525 .

The difference between the widths of the first upper counter portion 522 and the first lower counter portion 523 is defined as C _W , and the length of the first lower counter portion 523 is defined as C _W C _L.

In the case of C _L , it should be set to a length that can fully develop the widthwise velocity distribution. T _W and C _W can be determined based on the determined T _L and C _L as described above.

FIG. 7 is a graph showing the velocity distribution in a slot coating using a shim according to an embodiment of the present invention And the speed difference.

In FIG. 7, the velocity distribution and the velocity difference are shown in a state of being fixed at 3 mm. Comparing FIG. 4 and FIG. 7, it can be seen that when coated with the coating solution according to Table 1, the improvement ratio is about 70% as compared with the existing shim.

8 is a graph showing a correlation between C _W and T _W and a power-law index in a slot coating using a shim according to the present embodiment.

Here, the power-law index (n) is an index indicating the non-Newtonian property of the coating solution. The smaller the value, the greater the non-Newtonian property.

Referring to FIG. 8, it can be seen that it is preferable that T _w is set to be large for different C _W (0, 3, 6 mm) as n is smaller. Even if t _w is small, a uniform distribution is obtained Can be confirmed.

9 to 10 are views showing the shape of a shim according to another embodiment of the present invention.

9 to 10, the concave-convex portion 540 according to the present embodiment may have a shape protruding in the depth direction (direction D).

The shims shown in Figs. 9 to 10 are designed to alleviate stagnation portions that may occur at the clogged portions under the slit in the core shapes of Figs.

In the case of industrially applied coating solutions, it has the characteristics of a suspension. In the stagnant part, vortices are formed, so that entanglement may occur due to the generated vortex. Therefore, it is necessary to remove the stagnation part to improve the coating property by alleviating the particle flocculation phenomenon.

FIG. 11 is a graph showing changes in the vortex phenomenon in slot coating using a core shape according to an embodiment of the present invention.

Referring to FIG. 11, it can be seen that the size of the stagnation region varies according to the D direction (length in the chamber interior direction) when coating using the shims shown in FIGS. 5 to 6, Thereby providing concave and convex portions 540 protruding in the depth direction as shown in Fig.

FIG. 12 shows the shape in which the core is converging in the discharge direction of the coating liquid, and FIG. 13 shows the velocity distribution in the discharge portion in the case where the core has a converging shape.

Fig. 14 shows the shape of the shim diverging in the discharging direction of the coating liquid, and Fig. 15 shows the velocity distribution in the discharging portion when the shim has a shape diverging.

12 to 15, when the shim 504 has a shape converging or diverging, the velocity of the coating liquid tends to increase or decrease greatly in the shim discharge portion.

Accordingly, it is preferable that the first extension portion 520 and the second extension portion 530 according to the present embodiment extend parallel to the discharge direction, not converge or diverge.

It will be apparent to those skilled in the art that various modifications, additions and substitutions are possible, without departing from the spirit and scope of the invention as defined by the appended claims. Should be regarded as belonging to the following claims.

Claims (9)

A shim for uniform coating of the non-Newtonian coating fluid, disposed between the first slot die and the second slot die opposite to each other,
A coupling portion having a through-hole through which a bolt for coupling with the first slot die and the second slot die passes;
A first extension extending longitudinally from one side of the coupling;
A second extension portion facing the first extension portion and extending in the longitudinal direction at the other side of the engagement portion; And
And a concavo-convex portion located between the first extending portion and the second extending portion and protruding in a discharging direction of the coating liquid from one surface of the engaging portion. The method according to claim 1,
The second slot die is formed with a chamber for storing the coating liquid injected through the coating liquid injecting unit,
Wherein the concavo-convex portion protrudes in the coating liquid dispensing direction from the coating liquid injecting portion placement region. 3. The method of claim 2,
Wherein the concavo-convex portion protrudes from the central region of the chamber in the dispensing direction of the coating liquid. The method according to claim 1,
Wherein the concavo-convex portion has a shape in which the width of the concavo-convex portion decreases in the discharge direction of the coating liquid in the chamber. 5. The method of claim 4,
The concave-convex portion is a triangular-shaped core. The method according to claim 1,
Wherein the recessed portion protrudes in a depth direction and the depth direction is defined as a direction from the first slot die to the second slot die side. The method according to claim 1,
Wherein the first extending portion includes a first upper extending portion extending from the coupling portion and a first lower extending portion extending from the first upper extending portion in the coating liquid discharging direction,
The second extending portion includes a second upper extending portion extending from the coupling portion and a second lower extending portion extending from the second upper extending portion in the coating liquid discharging direction,
Wherein a widthwise distance between the first upper side facing portion and the second upper side facing portion is longer than a width direction distance between the first lower side facing portion and the second lower side facing portion. 8. The method of claim 7,
Wherein the first lower extension portion and the second lower extension portion are formed parallel to each other. A slot die coater for uniform coating of non-Newtonian coating fluids,
A first slot die;
A second slot die disposed opposite the first slot die; And
And a shim disposed between the first slot die and the second slot die,
Wherein the shim comprises a coupling portion having a through-hole through which a bolt for coupling with the first slot die and the second slot die passes, a first extending portion extending in a longitudinal direction from one side of the coupling portion, And a concavo-convex portion which is located between the first extending portion and the second extending portion and protrudes in a discharging direction of the coating liquid from one surface of the coupling portion, the second extending portion extending in the longitudinal direction at the other side of the coupling portion, .

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