KR102491325B1 - Coating apparatus and method for producing coating film - Google Patents

Abstract

A coating device or the like capable of efficiently forming a coating film in which variation in thickness in the width direction is sufficiently suppressed is provided.
A coating apparatus including a die for coating a coating liquid on a relatively moving object, wherein the die has the same shape and size of a cross section of the manifold viewed from the width direction across the width direction, A coating device configured so that the slot-side end edge of the manifold is formed into a shape drawing a quadratic curve determined from a specific expression.

Description

Coating device and manufacturing method of coated film {COATING APPARATUS AND METHOD FOR PRODUCING COATING FILM}

The present invention relates to a coating device and a method for producing a coating film.

Conventionally, as one type of coating apparatus, for example, a die coater is known. A die coater is a coating device that forms a coated film on a to-be-coated object such as a relatively moving substrate by discharging a coating liquid from a die. In such a coating device, the die communicates with a manifold that has an inlet and sends the coating liquid flowing in from the inlet toward at least one end in the width direction of the object to be coated, and the die It has an open slot at the leading edge.

In this type of coating apparatus, the manifold is formed across the width direction of the object to be coated, and the distance between the leading edge of the slot and the slot-side end edge of the manifold (length of the slot) is If it is the same across the width direction of the manifold, the pressure loss in the manifold and in the slot increases as the coating fluid is directed from the inlet of the manifold to the end. Owing to this, the flow rate of the coating liquid discharged from the slot decreases as it goes from the inlet to the end, and the thickness of the formed coating film decreases.

Accordingly, there is known a technique of designing a manifold having an inlet at one end in the width direction and having a coating liquid sent from the inlet to the other end in a specific shape, for example. Specifically, the flow rate of the coating liquid discharged from the slot is reduced by forming the edge of the slot side in the manifold so that the length of the slot decreases on a quadratic curve from one end to the other end in the width direction of the manifold. A technique for approaching uniformity from one end to the other has been proposed (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2002-72409

However, in the coating apparatus described above, there is a fear that it takes a lot of effort and time to appropriately determine the shape of the edge on the slot side of the manifold, and furthermore, there is a fear that it cannot be determined. This leads to the fact that the thickness of the coating solution cannot be sufficiently suppressed to fluctuate in the width direction.

In view of the above circumstances, an object of the present invention is to provide a coating device and a method for manufacturing a coated film capable of efficiently forming a coated film having a sufficiently suppressed variation in thickness in the width direction.

The inventors of the present invention conducted earnest research to solve the above problems and found the following findings.

In detail, the coating liquid flowing into the manifold is each virtual path that flows through the manifold and flows out from each predetermined position to the slot, and passes through the slot as the shortest distance and discharges from each position of the opening of the corresponding slot. Suppose you follow a virtual path. Further, it is assumed that the coating liquid discharged from the slot is a set of coating liquids discharged from the opening of the slot along each virtual path. In addition, it is assumed that each flow velocity at the opening of the slot in each virtual path is the same value between each virtual path across the width direction (for example, in FIG. 6, S ₀ =S ₁ =S ₂ . . . =S _M ).

The total pressure loss of the coating liquid discharged from the opening of the slot along each virtual path is the same between each virtual path, from the general knowledge of physics.

Therefore, based on the assumption regarding the flow rate, using the distance between the outflow position and the discharge position (the distance between the slot-side end edge of the manifold and the opening of the slot, that is, the slot length) and known parameters, each If it becomes possible to formulate the total voltage loss in a virtual path, it becomes possible to calculate each slot length at each position so that the total voltage loss in each virtual path becomes a mutually equal value between each virtual path.

Then, a graph in which the calculated slot lengths are plotted for each ejection position is created, and a quadratic approximate curve is calculated from this graph. The slot side end edge (slot side end edge) of the manifold is formed so as to have a shape along the calculated quadratic approximation curve, and the shape and size of the cross section of the manifold viewed from the width direction are in the width direction form a manifold so that it is the same throughout. Thereby, the flow rate of the coating liquid discharged from the slot can be brought closer to the same value over the entire slot (the entire width direction of the object to be coated).

As described above, the total pressure loss of each virtual path is Determine the length of each slot to be constant. A manifold and a slotted die are used so as to have a shape along a quadratic approximation curve obtained from each determined slot length. As a result, it was discovered that a coated film with little variation in thickness in the width direction could be formed, and the present invention was completed.

That is, the coating device according to the present invention,

A coating device provided with a die for coating a coating liquid on a relatively moving object,

The die,

a manifold having an inlet through which the coating liquid flows and sending the coating liquid flowing in from the inlet toward the width direction of the object to be coated;

a slot communicating with the manifold and having an opening at the leading edge of the die;

The shape and size of the cross section of the manifold viewed from the width direction are the same throughout the width direction,

The opening of the slot extends along the width direction,

An end or center in the width direction of a region in the opening where the coating liquid is discharged from the slot is set as an origin, and an x-axis is set from the origin along the opening in a direction in which the coating liquid is sent, , when the y-axis is set in a direction perpendicular to the x-axis from the origin,

The slot side end edge of the manifold is formed in a shape drawn by a quadratic curve represented by the following formula (1),

The coating liquid flowing into the manifold from the inlet port flows out into the slot from the slot side end edge at a plurality of outflow positions arranged in the width direction and passes through the slot in a direction parallel to the y-axis When it is assumed to follow each virtual path discharged from a plurality of discharge positions of the opening,

In the virtual path of the mth (m is an integer greater than or equal to 0) from the origin, the distance from the origin to the discharge position is x _m [m], and the total pressure loss of the coating solution from the inlet to the opening is ΔP _m [Pa], when the distance between the outflow position and the discharge position is represented by L _m [m], respectively,

The relationship between ΔP _m and L _m is represented by Equations (2) and (3) below,

While satisfying Equations (2) and (3), each L _m is calculated so that each ΔP _m in each virtual path becomes the same value among each virtual path, and the calculated angle L _m and the corresponding angle L _m As a quadratic approximate curve of a graph on which the relation of x _m corresponding to is plotted, the quadratic curve is configured to be determined.

A, B, C: Coefficient[-]

W: coating width [m]

Q ₁ : Flow rate of the coating liquid flowing into the manifold [m3/s]

Q ₂ : Flow rate of the coating fluid flowing out from the manifold other than the slot [m3/s]

S: Flow rate of the coating liquid discharged from the slot (S=(Q ₁ -Q ₂ )/W) [m 2 /s]

h : slot height [m]

R : radius of manifold [m]

n _c : 1st viscosity parameter of the coating solution in the manifold [-]

η _c : 2nd viscosity parameter of the coating solution in the manifold [-]

n _s : first viscosity parameter of the coating solution in the slot [-]

η _s : second viscosity parameter of the coating solution in the slot [-]

The above configuration will be described in detail. The above equation derived based on the assumption that the shape and size of the cross section of the manifold viewed from the width direction are the same across the width direction, and that the flow rates of the coating liquid discharged from the openings of the slots between each virtual path are the same value. (2) and Equation (3) are used. Thus, each ΔP _m represented by the known parameter and the unknown distance (slot length) L _m between the discharge position and the discharge position (i.e., the opening) becomes the same value between each virtual path, Each L _m is calculated. Based on the calculated angle L _m , a quadratic approximation curve is determined. The slot-side end edge of the manifold is formed so as to follow this second-order approximation curve. In addition, according to these end edges, a manifold is formed so that the shape and size of the cross section viewed from the width direction are the same over the width direction.

By forming the manifold in this way, the flow rate of the coating liquid discharged from the opening of the slot can be brought close to the same value over the width direction of the object to be coated. Therefore, fluctuations in the thickness of the formed coating film can be suppressed over the width direction.

Also, since the quadratic approximation curve can be determined from known parameters, it is efficient.

Therefore, it is possible to efficiently form a coated film in which variation in thickness in the width direction is sufficiently suppressed.

The method for producing a coated film according to the present invention includes a step of forming a coated film by discharging a coating liquid onto a relatively moving object to be coated using the above coating device.

According to this structure, since the said coating apparatus is used, the coating film in which the fluctuation|variation of the thickness in the width direction is sufficiently suppressed can be formed efficiently.

1 is a schematic side view showing a coating device according to an embodiment of the present invention.
Fig. 2 is a schematic plan view showing an example of manifolds and slots of dies provided in the coating apparatus of the present embodiment, together with the flow of a coating liquid from the manifold to the slots.
Fig. 3 is a schematic side view showing a die of this embodiment;
FIG. 4 is a schematic plan view schematically showing each virtual path of the coating liquid in the manifold and slot in FIG. 2 and the pressure loss in each virtual path.
5 is a graph showing an example of a viscosity curve of a coating solution.
Fig. 6 is a schematic plan view schematically showing each flow velocity from the opening of a slot in each virtual path of the coating liquid of Fig. 4;
Fig. 7 is a schematic plan view schematically showing slot lengths in each virtual path of the coating solution of Fig. 4;
Fig. 8 is a graph showing an example of the relationship between the distance from the origin in the x-axis direction and the slot length in each virtual path.
Fig. 9 is a schematic view showing an example of the cross-sectional shape and cross-sectional radius of a manifold;
Fig. 10 is an outline schematically showing each virtual path of a coating liquid in a manifold and a slot of a die provided in another coating device of the present embodiment, and each flow velocity from an opening of a slot in each virtual path. Floor plan.
Fig. 11 is a schematic plan view schematically showing each virtual path of a coating liquid in a manifold and a slot of a die provided in another coating device of the present embodiment, and each flow rate from an opening of a slot in each virtual path. .
Fig. 12 is a schematic plan view schematically showing slot lengths in each virtual path of the coating solution of Fig. 11;
Fig. 13 is a schematic plan view showing an example of manifolds and slots of dies provided in another coating device of the present embodiment, together with the flow of a coating liquid from the manifold to the slots.
FIG. 14 is a schematic plan view schematically showing each virtual path of the coating liquid in the manifold and slots of FIG. 13 and each flow velocity from the opening of the slot in each virtual path.
Fig. 15 is a schematic plan view schematically showing slot lengths in each virtual path of the coating solution of Fig. 13;
Fig. 16 is a graph showing the viscosity curve of the coating solution used in Example 1;
Fig. 17 is a graph showing an example of the relationship between the distance from the origin in the x-axis direction and the slot length in each virtual path in Example 1;
Fig. 18 is a graph showing the relationship between the thickness of a coated film formed by a coating apparatus equipped with a die having a manifold of Example 1 and the distance from the origin in the x-axis direction.
Fig. 19 is a schematic plan view showing a manifold shape of a die of Comparative Example 1;
20 is a graph showing an example of the relationship between the distance from the origin in the x-axis direction and the slot length in each virtual path in Comparative Example 1;
Fig. 21 is a graph showing the relationship between the thickness of a coated film formed by a coating apparatus equipped with a die having a manifold of Comparative Example 1 and the distance from the origin in the x-axis direction.
Fig. 22 is a schematic plan view showing the shape of a die manifold of Comparative Example 2;
Fig. 23 is a graph showing the relationship between the thickness of a coated film formed by a coating apparatus equipped with a die having a manifold of Comparative Example 2 and the distance from the origin in the x-axis direction.

First, a coating device according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1, 2 and 3, the coating device 1 of this embodiment uses a die 5 for coating a coating liquid 33 on a relatively moving object 31. It is the coating apparatus 1 provided. The coating device 1 provided with a die in this way is called a die coater.

The die 5,

It is a manifold 9 having an inlet 10 through which the coating liquid 33 flows, and the coating liquid 33 flowing in from the inlet 10 is passed to both ends in the width direction of the object 31 to be coated. A manifold 9 directed toward at least one end of (9a, 9b);

A slot 8 communicating with the manifold 9 and having an opening 8a at the leading edge 5a of the die 5, and sending a coating liquid 33 from the outside to the inlet 10 It has a supply part 11 constituting the path.

In this embodiment, the inlet port 10 is formed at one end (first end) 9a of the manifold 9, and the coating liquid 33 flowing in from the inlet port 10 passes through the other end portion. The coating apparatus 1 (the said die 5) is comprised so that it may be sent toward the (2nd end part) 9b.

The coating device 1 further includes a solidifying portion 17 that forms each coating film 35 by solidifying the coating liquid 33 coated with the die 5 . In addition, the coating apparatus 1 does not need to be provided with the solidifying part 17.

The coating device 1 further includes a support portion 15 for relatively moving the object 31 in the longitudinal direction with respect to the die 5 while supporting the object 31 on the surface thereof. . In addition, the coating apparatus 1 does not need to be equipped with the support part 15.

Although it does not specifically limit as to-be-coated object 31, For example, a strip|belt-shaped sheet member etc. are mentioned.

As such a sheet member, a resin film is mentioned, for example. Moreover, as a resin film, Lumirror (registered trademark) by a Toray Industries, Ltd., etc. are mentioned, for example.

The support portion 15 supports the coated object 31 moving in the longitudinal direction from the side opposite to the side on which the die 5 is disposed. The coating liquid 33 is applied to the object 31 moving relative to the die 5 while being supported by the support portion 15 .

As such a support part 15, a roller etc. are mentioned.

In this embodiment, the support portion 15 is disposed at a position facing the slot 8 of the die 5, and is relatively from one side (lower side in FIG. 1) to the other side (see FIG. upward of 1), it is comprised so that the to-be-coated object 31 may be moved.

The solidifying unit 17 is configured to solidify the coating liquid 33 to form the coating film 35 . By this solidified part 17, the solidified coating film 35 is formed. The solidified part 17 should just be what can solidify the coating liquid 33, and is not specifically limited. This solidified portion 17 is appropriately set depending on the type of coating liquid 33 and the like.

The die 5 is configured to discharge the coating liquid 33 from the slot 8 and coat the coating film 35 on the relatively moving object 31 .

The die 5 is arranged so that the slot 8 faces sideways, and is configured to discharge the coating liquid 33 to the object 31 moving in the vertical direction relative to the slot 8. there is. In the coating device 1, the coating liquid 33 is supplied to the die 5 from a housing portion (not shown) of the coating liquid 33 through a pipe (not shown) and a pump (not shown). It is composed so that Further, the die 5 may be arranged so that the slot 8 faces downward or upward.

Specifically, the die 5 includes an upstream first dive lock 6 and a downstream second dive lock 7 arranged to face the first dive lock 6 . The die 5 is formed by putting the first dive lock 6 and the second dive lock 7 together. In this way, by putting both dive locks 6 and 7 together, the manifold 9 in which the coating liquid 33 supplied by the pump (not shown) is stored between them, and the manifold 9 ), a slot 8 toward the tip edge, and a supply portion 11 are formed. Further, the gap between the tip edge of the first dive lock 6 and the tip edge of the second dive lock 7 is the opening 8a (discharge port) of the slot 8. The opening 8a extends along the width direction of the object 31 to be coated.

In FIG. 1 , a die 5 without a shim is shown, and a die 5 in an aspect in which a first dive lock 6 and a second dive lock 7 are put together is shown. In addition, the die 5 of the aspect in which the 1st dive lock 6 and the 2nd dive lock 7 are put together via a shim may be employ|adopted.

The tip edge of the first dive lock 6 and the tip edge of the second dive lock 7 are arranged so as to be positioned on a plane perpendicular to the radial direction of the support portion 15 . The slots 8 are arranged in a direction parallel to the normal direction of the support 15 .

The manifold 9 is formed so that the shape and size of the cross section of the object 31 viewed from the width direction are the same throughout the width direction.

The shape of the cross section of the manifold 9 is not particularly limited, but may be a circular shape, a semicircular shape, a fan shape, or the like, as shown in FIG. 9 described later. The size of the cross section of the manifold 9 is not particularly limited either.

The radius of the cross section of the manifold 9 will be described later.

In the coating apparatus 1 of this embodiment, the inlet 10 is formed in the 1st end part 9a of the said width direction one side, in detail, the manifold 9. The coating liquid 33 is sent from the first end portion 9a toward the second end portion 9b. Further, when the flat surface on the side where the manifold 9 is formed in the dive lock 6 (here, the first dive lock) is viewed from the direction perpendicular to this surface, the opening 8a of the slot 8 The end in the width direction of the area (coating area F) in which the coating liquid 33 is discharged from the slot 8 in ) is set to the origin O. The direction from the origin O to the second end portion 9b, which is the moving destination of the coating liquid 33 along the opening 8a, is set as the x-axis. A direction perpendicular to the x-axis from the origin is set as the y-axis (see FIGS. 4, 6, and 7).

In addition, the edge part of the width direction of the coating area F is the edge part of the to-be-coated object 31 in the width direction in the coating area F. In addition, the end set to origin O is the end of the side close to the inlet 10 in the coating area|region F.

Further, as shown in Figs. 4, 6 and 7, the coating liquid 33 flowing into the manifold 9 from the inlet port 10 is formed in a plurality of lines at the edge 9c arranged in the width direction. Each virtual path K (here, K ₀ to K _M , where M is an integer greater than or equal to 1) is assumed to follow. In the virtual path K _m of the mth (m is an integer greater than or equal to 0) from the origin O, the distance from the origin O to the discharge position is represented by x _m [m], and from the inlet 10 to the opening 8a The total pressure loss of is represented by ΔP _m [Pa], and the distance between the outflow position and the discharge position (slot length) is represented by L _m [m].

At this time, the relationship between ΔP _m and L _m is represented by Equations (2) and (3) below, and each ΔP _m in each virtual path K _m satisfies Equations (2) and (3 ₎ . As a quadratic approximate curve of a graph in which each L _m is calculated to be the same value in , and the relationship between each L _m calculated and x _m in each virtual path K is plotted, the quadratic curve of Equation (1) below decide

A, B, C: Coefficient[-]

W: coating width [m]

Q ₁ : Flow rate of the coating liquid flowing into the manifold [m3/s]

Q ₂ : Flow rate of the coating fluid flowing out from the manifold other than the slot [m3/s]

S: Flow rate of the coating liquid discharged from the slot (S=(Q ₁ -Q ₂ )/W) [m 2 /s]

h : slot height [m]

R : radius of manifold [m]

n _c : 1st viscosity parameter of the coating solution in the manifold [-]

η _c : 2nd viscosity parameter of the coating solution in the manifold [-]

n _s : first viscosity parameter of the coating solution in the slot [-]

η _s : second viscosity parameter of the coating solution in the slot [-]

The above formulas (1), (2) and (3) will be described below.

The quadratic curve represented by Equation (1) draws the shape of the edge 9c on the slot side of the manifold 9.

The derivation of this quadratic curve, that is, the determination of the coefficients A, B and C, will be described later.

Equations (2) and (3) are equations calculated based on the following assumptions.

In detail, the coating liquid 33 flowing into the manifold 9 flows out into the slot 8 from a plurality of outflow positions arranged in the width direction at the end edge 9c, parallel to the y-axis. It is assumed that each virtual path K passing through the slot 8 in the direction and ejected from a plurality of ejection positions of the opening 8a is followed.

Equations (2) and (3) express the distance from the origin O to the discharge position in the m-th virtual path K _m from the origin O as x _m [m], and from the inlet 10 to the opening 8a ) is expressed as ΔP _m [Pa], and the distance between the outflow position and the discharge position (slot _length ) is expressed as L _m [ _m ]. In Formulas (2) and (3), the slot height is the spacing in the direction perpendicular to the width direction of the opening 8a of the slot 8.

In addition, from the origin O (x ₀ [m]), the 0th discharge position is the origin itself, the 1st discharge position is x ₁ [m] apart, and the 2nd discharge position is x ₂ [m] apart, , … , the m-th discharge position is x _m [m] apart. Each ejection position may be spaced apart from each other at equal intervals, or may be spaced apart from each other at different intervals. Similarly, even if each outflow position is spaced apart from each other at equal intervals, they may be spaced apart from each other at different intervals.

In the present embodiment, for ΔP _m in each virtual path K _m passing through each outflow position and each discharge position, while satisfying Expressions (2) and (3), each ΔP _m is between each virtual path K _m Each L _m is calculated so that it becomes a mutually equal value.

In addition, a graph plotting the relationship between the calculated angle L _m and the corresponding angle x _m is created.

Then, a quadratic approximate curve of the created graph is determined as a quadratic curve drawn by the end edge 9c of the manifold 9 .

Derivation of Expressions (2) and (3) will be described.

As shown in Fig. 4, when the coating liquid 33 is being discharged from the slot 8 of the die 5, the discharge position in the width direction of the slot 8 is correlated from the general knowledge of the physical laws. Assuming that the total pressure loss of the coating solution 33 from the inlet 10 to the opening 8a of the slot 8 is the same between each virtual path, in any m-th path, the following formula (3) holds.

Based on the above assumption that the total pressure loss is the same regardless of the position of the slot 8 in the width direction, the total pressure loss ΔP of the coating liquid 33 flowing in from the inlet 10 and discharged from the slot 8 is , It is represented like the following formulas (4) and (5), and is specifically represented like the following formula (6). Also, the pressure loss in the y-axis direction in the manifold 9 is zero. Moreover, i is an integer of 1 or more and m or less.

In general, the relationship between the shear rate and viscosity of a liquid is expressed by the following formula (7) using two viscosity parameters.

For the coating liquid 33, when the relationship between the shear rate and the viscosity is obtained, a graph as shown in FIG. 5 is obtained.

Here, if the area of the graph corresponding to the shear rate of the portion passing through the manifold 9 and the area of the graph corresponding to the shear rate of the portion passing through the slot 8 are examined in advance, for example In the graph of FIG. 5, two regions are respectively shown. That is, in these two regions, the relationship between the shear rate and the viscosity of the above formula (7) is established, respectively.

From this, the relationship between the shear rate and the viscosity when the coating liquid 33 passes through the manifold 9 is represented by the following formula (8). In addition, the relationship between the shear rate and the viscosity when the coating liquid 33 passes through the slot 8 is represented by the following formula (9).

And it is assumed that the shape and size of the cross section of the manifold 9 viewed from the width direction are the same across the width direction, and the flow rate of the coating liquid discharged from the opening 8a of the slot 8 is the same across the width direction. (That is, S ₀ to S _M are the same value), according to Equation (6), under the assumption that the known parameter called the viscosity parameter and the unknown slot length (the distance between the end edge 9c and the opening 8a) ) L _m to formulate the total pressure loss ΔP _m in each virtual path K _m , the above formulas (2) and (3) are obtained.

In Equations (2) and (3), the pressure loss in slot 8 ΔP _sm , the pressure loss in manifold 9 ΔP _cm , and the total pressure loss ΔP _m (pressure loss in slot 8 ΔP _sm and It is the sum of the pressure losses ΔP _cm in the manifold 9, and in FIG. 4, P _IN -P _outm =ΔP _m ), each virtual path K _m from the 0th to the Mth (K ₀ , K ₁ , ... K _M ) is shown in FIG. 4 . The flow rate S _m of the coating liquid 33 discharged from the opening 8a is represented as shown in FIG. 6 . The slot length L _m is represented as shown in FIG. 7 .

And, according to the above assumption that the total voltage loss ΔP _m is the same value between each virtual path K _m , each slot in which the total voltage loss ΔP _m in each virtual path K _m is the same value between each virtual path K _m . Calculate the length L _m . This calculation is performed using, for example, an add-in solver of conventionally known table calculation software (for example, "MICROSOFT EXCEL (registered trademark)" manufactured by Microsoft Corporation). Here, the mutually equal value means a mutual value at which an error function representing a degree of difference (error) between the mutual values is minimized.

4, 6, and 7 show the shape of the end edge 9c initially set before calculating L _m using Equations (2) and (3) as the width of the object 31 to be coated. An aspect set to a shape extending linearly in the direction (x-axis direction) is shown. However, the shape of the edge 9c initially set is not particularly limited, and may be straight or quadratic.

The number of outflow locations and discharge locations through which the virtual path K passes (ie, the value of m), and the interval ( _Δx ) between the outflow locations and the discharge locations are not particularly limited and may be appropriately set. there is.

For example, as the value of the quantity m of the outflow position and the discharge position (quantity of the virtual path) is larger, the coating liquid 33 discharged from the slot 8 over the entire width direction of the object 31 While it becomes possible to make the flow rate more uniform, the calculation tends to be complicated.

Therefore, for example, considering this point of view, it is possible to appropriately set the quantity and interval of the outflow position and the discharge position.

Further, it is preferable that the intervals between the outflow position and the discharge position are equal intervals.

When each slot length L _m obtained in this way is plotted against each distance x _m and made into a graph, a graph shown in FIG. 8 is obtained, for example.

If this graph is approximated with a quadratic function, a quadratic approximation curve is obtained as shown in FIG. 8 .

Equation (1) is specifically determined by adopting each coefficient of the obtained quadratic approximate curve as the coefficients A, B, and C in the above-mentioned equation (1).

Then, the end edge 9c is formed so as to follow the determined formula (1). Further, a manifold 9 is formed along this end edge 9c so that the shape and size of the cross section viewed from the width direction are the same throughout the width direction.

Moreover, since A approaches 0 in Formula (1) when the coating liquid 33 is a Newtonian fluid, an approximation curve approaches a straight line with an inclination. Further, when the coating liquid 33 is a Newtonian fluid, the viscosity is relatively low, and the flow rate of the coating liquid 33 discharged from the opening 8a of the slot 8 is relatively small, both A and B are 0. , the coating liquid 33 approaches a straight line parallel to the x-axis.

Also, as described above, and also as is clear from equations (2) and (3), since the shape and size of the cross section of the manifold 9 are the same across the width direction (i.e., the x-axis direction), , the radius R of the cross section of the manifold 9 is also the same over the width direction (ie, the x-axis direction).

As shown in FIG. 9 , the radius of the manifold 9 (radius of the cross section) is determined by the shape of the cross section of the manifold 9 viewed in the moving direction of the coating liquid 33, and the shape factor D is used. So it can be set by the formula of R=D×r. For example, when the shape of the cross section is circular, the radius of the manifold 9 can be employed as the radius r of the circle.

On the other hand, when the shape of the cross section is a semicircular shape or fan shape, the radius of each cross section can be set using the shape factor D as shown in FIG. 9 .

Further, as shown in FIG. 2 , the slot 8 and the opposite end edge 9d in the manifold 9 have the same spacing with the end edge 9c over the width direction, so that the end edge It is formed in the same shape as (9c).

As described above, in the coating apparatus 1 according to the present embodiment, the shape and size of the cross section of the manifold 9 viewed from the width direction are the same throughout the width direction, and the slot 8 of the manifold 9 The side edge 9c is formed in a shape drawing a quadratic curve represented by the following formula (1), the relationship between ΔP _m and L _m is expressed by the following formulas (2) and (3), and While satisfying (2) and (3), each L _m is calculated so that each ΔP _m at each outflow position and each discharge position becomes the same value between each virtual path K _m , and the calculated angle L _m and the corresponding angle L A quadratic approximate curve of a graph plotting the relationship of x _m corresponding to _m , which is configured to determine the quadratic curve.

This configuration will be described. Assuming that the shape and size of the cross section of the manifold 9 viewed from the width direction are the same across the width direction, and the flow rate of the coating liquid 33 discharged from the opening 8a of the slot 8 between each virtual path K _m Equations (2) and (3) derived based on the assumption that S _m are equal to each other are used. Then, the unknown distance (slot length) L between the known parameter and the discharge position (end edge 9c on the slot 8 side of the manifold 9) and the discharge position (i.e., opening 8a) Each L _m is calculated so that ΔP _m represented by _m becomes a mutually equal value between each virtual path K _m . Based on the calculated L _m , a second-order approximation curve is determined. And the end edge 9c of the slot 8 side of the manifold 9 is formed so that it may follow this 2nd order approximation curve. Fitted with this end edge 9c, a manifold 9 is formed so that the shape and size of the cross section viewed from the width direction are the same over the width direction.

By forming the manifold 9 in this way, the flow rate of the coating liquid 33 discharged from the opening 8a of the slot 8 can be brought close to the same value over the width direction of the object 31 to be coated. there is. Thereby, the fluctuation|variation of the thickness of the formed coating film 35 can be suppressed over the width direction.

Also, since the quadratic approximation curve can be determined from known parameters, it is efficient.

Therefore, it is possible to efficiently form the coated film 35 in which variation in thickness in the width direction is sufficiently suppressed.

Next, the manufacturing method of the coating film 35 of this embodiment is demonstrated.

The method for manufacturing a coated film according to the present embodiment is a step of forming a coated film 35 by discharging a coating liquid 33 onto a relatively moving object 31 using the coating device 1 described above. to provide

According to the above manufacturing method, since the coating device 1 is used, it is possible to efficiently form the coated film 35 in which variation in thickness in the width direction is sufficiently suppressed.

As described above, according to the present invention, a coating device and a coating film manufacturing method capable of efficiently forming a coating film having a sufficiently suppressed variation in thickness in the width direction are provided.

Although the coating apparatus and the manufacturing method of the coating film of this embodiment are as above-mentioned, this invention is not limited to the said embodiment, It is possible for design change suitably within the range intended by this invention.

The above embodiment shows an aspect in which all of the coating liquid 33 flowing in from the inlet 10 flows out into the slot 8 (eg, Q ₂ =0 in FIG. 6 ). However, for example, in the present invention, as shown in FIG. 10, the manifold 9 has a discharge port (in addition to the slot 8) that allows the coating liquid 33 to flow out from the inside of the manifold 9 ( 12), and the die 5 has a discharge portion 13 constituting a path for sending the coating liquid 33 from the discharge port 12 to the outside, and a part of the coating liquid 33 introduced from the inlet port 10. An aspect in which the gas flows out into the slot 8 and the remainder is discharged from the discharge port 12 through the discharge portion 13 may be employed.

As shown in FIG. 2, the said embodiment shows the aspect which is located so that the edge part of the coating area|region F may overlap with the inlet 10. However, in this invention, the aspect in which the edge part of the coating area|region F is located inside rather than the inlet 10 may be employ|adopted, for example as shown in FIG.11, FIG.12. In the aspect shown in FIG. 11, the restricting part 21 which regulates the discharge of the coating liquid 33 is arrange|positioned at both ends of the opening 8a of the slot 8 in the width direction, respectively. The width|variety (coating width W) of the coating area|region F is small by the amount these regulation parts 21 are arrange|positioned.

In the above embodiment, as shown in FIG. 2, the inlet 10 is formed at the first end 9a of the manifold 9, and the coating liquid 33 flowing in from the inlet 10 is An aspect of being sent from the end portion 9a to the second end portion 9b is shown. However, in the present invention, the position where the inlet 10 in the manifold 9 is formed may be a position corresponding to the center of the coating region F, as shown in Figs. 13 to 15, for example. .

In this case, as shown in FIGS. 13 and 14, the inlet 10 is formed at the center of the manifold 9 in the width direction of the object 31, and the center of the inlet is the center of the coating area F. , and the coating liquid 33 flowing from the inlet 10 is directed toward both sides of the first end 9a and the second end 9b (ie, both ends).

At this time, it is assumed that the flow of the coating liquid 33 is linearly symmetrical about a virtual straight line (not shown) that passes through the center of the coating area F and is parallel to the y-axis as the central axis. Then, as shown in FIG. 15, the center of the coating area F is set as the origin O, and each L _m is formed in the same manner as above for the coating liquid 33 sent from the origin O to the downstream second end portion 9b. If determined, each L _m will be determined similarly also for the coating liquid 33 from the origin O toward the other first end portion 9a. In addition, the center of the coating area F is a position where the coating area F is halved (1/2) in the width direction (ie, the moving direction of the coating liquid), and the center of the inlet 10 is the position where the inlet 10 is moved in the width direction. It is a position that is halved (1/2) by .

[Example]

Next, the present invention will be described in more detail with test examples, but the present invention is not limited thereto.

Example 1

(Material used)

Object to be coated: PET (polyethylene terephthalate) film (trade name: Dia foil, manufactured by Mitsubishi Chemical Corporation)

・Coating solution: Acrylic polymer (trade name: SK Dine, manufactured by Soken Chemical Co., Ltd.)

Regarding the coating solution, the viscosity at each shear rate was measured according to the method described below and graphed. From the obtained graph, the first and second viscosity parameters of the coating solution in the manifold, the first and second viscosity parameters of the coating solution in the slot, and the like were measured. The results are shown in Table 1.

(Viscosity measurement method)

Using a rheometer (model RS1, manufactured by HAAKE) equipped with a jig (a cone plate with a cone diameter of 25 to 50 mm and a cone angle of 0.5 to 2 °), under temperature and humidity conditions of 23 ° C. and 50% RH, The viscosity of the coating solution was measured. At this time, each viscosity was measured by changing the shear rate.

The results are shown in FIG. 16 . Further, from these results, first and second viscosity parameters in the manifold and in the slot were calculated, respectively.

Specifically, in the shear rate-viscosity curve shown in FIG. 16, the range of shear rate corresponding to the flow of the coating liquid in the manifold and the flow of the coating liquid in the slot, respectively, was determined by a preliminary experiment.

By approximating the shear rate-viscosity curve within the determined range of each shear rate with the above-mentioned equations (8) and (9), the first and second viscosity parameters (n _c , η _c ) and slots of the coating liquid in the manifold The first and second viscosity parameters (n _s , η _s ) of the coating solution within were respectively determined.

(calculation of flow rate S)

The flow rate S was calculated by the formula of S = (coating thickness (wet) of the set coating solution) × (moving speed of the object to be coated).

(Determination and Formation of Manifold Shape)

As shown in FIG. 3, the cross section viewed from one side in the width direction is semicircular, and as shown in FIG. 4, it is a manifold extending in the width direction, and has a manifold whose cross section shape and size are constant throughout the width direction. based on the die. In the die, the inlet is formed at the first end of the manifold, while the outlet is not formed. The shape of the manifold was determined as follows.

As shown in Table 1, the width of the coating fluid applied to the object to be coated, the moving speed (line speed) of the object to be coated by the support, the flow rate of the coating fluid when flowing into the manifold, the manifold radius, the slot height, etc. set together. Using Equations (2) and (3 ₎ , if the slot _length L _m of each virtual path K _m passing through each outflow position and discharge position is It was calculated as possible. In calculation, the value shown in Table 1 was used as the initial value (L ₀ ) of each ΔL _m .

Then, the relationship between the discharge position on the x-axis and the slot length L _m was plotted and approximated with a quadratic function to obtain a quadratic approximation curve. The results are shown in FIG. 17 .

The shape drawn by the obtained quadratic approximation curve was determined as the shape of the edge on the slot side of the manifold. The manifold was formed such that the shape and size of the cross section of the manifold at the origin O were the same throughout the width direction, that is, such that the shape and size of the cross section of the manifold were constant in the width direction. In this way, a manifold as shown in FIG. 2 was formed.

Using a die having the formed manifold, coating was applied to the object to be coated under the conditions shown in Table 1. The coated coating solution was dried to form a coating film. The thickness of the obtained coating film was measured across the width direction using a linear gauge. The results are shown in FIG. 18 .

As shown in Fig. 18, a coated film in which variation in thickness was suppressed across the width direction was obtained.

Comparative Example 1

As shown in Fig. 19, a manifold was fabricated. Specifically, the slot-side end edge of the manifold is straight along the leading edge (opening of the slot) of the die (that is, parallel to the x-axis direction), and the shape and size of the cross section viewed from the width direction are A manifold was fabricated so as to be identical to the manifold of Example 1 throughout the width direction. The slot length L of this manifold was 40 mm, and as shown in Fig. 20, it was the same across the width direction.

Coating was performed in the same manner as in Example 1 under the conditions of Table 2 using a die having a manufactured manifold. The thickness of the obtained coating film was measured across the width direction.

Results are shown in FIG. 21 .

As shown in FIG. 21, the thickness of the obtained coating film varied greatly in the width direction.

Comparative Example 2

In the manifold of Comparative Example 1, as shown in FIG. 22, processing was added so that only the slot-side end edge had the same shape (same slot length) as the slot-side end edge of Example 1. In other words, in the manifold of Example 1, processing was added so that the end edge on the side opposite to the slot had the same shape as that of Comparative Example 1 (see Fig. 19). The shape of the cross section of this manifold viewed from the width direction was semicircular and constant throughout the width direction. The size of the cross section was larger toward the downstream side in the moving direction of the coating liquid.

Coating was performed in the same manner as in Example 1 using a die having a manufactured manifold. The thickness of the obtained coating film was measured across the width direction.

The result is shown in FIG. 23.

As shown in FIG. 23, in the obtained coated film, the variation in thickness in the width direction was suppressed more than in Comparative Example 1, but was larger than in Example 1.

Further, in Comparative Example 2, streaks occurred on the coated film. The reason for this is that in Comparative Example 2, since the shape of the cross section of the manifold is different in the width direction, the speed change of the coating liquid in the manifold becomes not uniform in the width direction (not a monotonic change), and as a result, It is thought that this is because the flow of the coating liquid was greatly disturbed within the manifold.

In contrast, in Example 1, streaks did not occur. The reason for this is that if the shape and size of the cross section of the manifold are the same in the width direction as in Example 1, since the moving speed of the coating fluid in the manifold changes monotonically, the flow of the coating fluid in the manifold is disturbed. I think it's because it's difficult to do.

1: coating device
5: die
8 : Slot
8a: opening
9: Manifold
9a: first end
9b: second end
9c, 9d: end edge
10: inlet
12: outlet
15: support
17: solidification part
31: object to be coated
33: coating liquid
35: coated film

Claims (2)

A coating device provided with a die for coating a coating liquid on a relatively moving object,
The die,
a manifold having an inlet through which the coating liquid flows and sending the coating liquid flowing in from the inlet toward the width direction of the object to be coated;
a slot communicating with the manifold and having an opening at the leading edge of the die;
The shape and size of the cross section of the manifold viewed from the width direction are the same throughout the width direction,
The opening of the slot extends along the width direction,
An end or a center in the width direction of a region in the opening where the coating liquid is discharged from the slot is set as an origin, and an x-axis is set along the opening from the origin in a direction in which the coating liquid is sent, , when the y-axis is set in a direction perpendicular to the x-axis from the origin,
The slot side end edge of the manifold is formed in a shape drawn by a quadratic curve represented by the following formula (1),
The coating liquid flowing into the manifold from the inlet port flows out into the slot from the slot side end edge at a plurality of outflow positions arranged in the width direction and passes through the slot in a direction parallel to the y-axis When it is assumed to follow each virtual path discharged from a plurality of discharge positions of the opening,
In the virtual path of the mth (m is an integer greater than or equal to 0) from the origin, the distance from the origin to the discharge position is x _m [m], and the total pressure loss of the coating solution from the inlet to the opening is ΔP _m [Pa], when the distance between the outflow position and the discharge position is represented by L _m [m], respectively,
The relationship between ΔP _m and L _m is represented by Equations (2) and (3) below,
While satisfying Equations (2) and (3), each L _m is calculated so that each ΔP _m in each virtual path becomes the same value among each virtual path, and each L _m calculated and each L _m As a quadratic approximate curve of a graph on which the relationship of x _m corresponding to is plotted, the coating apparatus configured to determine the quadratic curve.

A, B, C: Coefficient[-]

W: coating width [m]
Q ₁ : Flow rate of the coating liquid flowing into the manifold [m3/s]
Q ₂ : Flow rate of the coating fluid flowing out from the manifold other than the slot [m3/s]
S: Flow rate of the coating liquid discharged from the slot (S=(Q ₁ -Q ₂ )/W) [m 2 /s]
h : slot height [m]
R : radius of manifold [m]
n _c : 1st viscosity parameter of the coating solution in the manifold [-]
η _c : 2nd viscosity parameter of the coating solution in the manifold [-]
n _s : first viscosity parameter of the coating solution in the slot [-]
η _s : second viscosity parameter of the coating solution in the slot [-] A method for producing a coated film comprising the step of discharging the coating liquid onto a relatively moving object to be coated using the coating device according to claim 1 to form a coated film.

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