KR20220145907A - Method for manufacturing a coating film - Google Patents

Abstract

The present disclosure provides a step A of continuously conveying a long support having a thermal conductivity of 200 W/(m·K) or more and applying an aqueous coating solution on the continuously conveyed support, and a step B of drying the coating solution film obtained in step A. A method for producing a coating film, wherein the process B includes a constant constant drying step of the coating film that satisfies the conditions (1) and (2) (Condition (1): Coating liquid film at the time T0% when constant constant drying is started A _(T0%) of the film surface temperature of the end of the width direction, B _(T0%) of the film surface temperature of the central portion of the width direction, at the time of T90% after 90% of the constant drying time, the width direction of the coating solution film When the film surface temperature of the edge portion is A _(T90%) and the film surface temperature of the central portion in the width direction is B _(T90%) , ΔT[°C] obtained from the formula (A) is -10°C<ΔT<0°C. (2): The average value of the film surface temperatures A _(T0%) , B _(T0%) , A _(T90%) , and B _(T90%) is 35° C. or higher) is provided.

Description

Method for manufacturing a coating film

The present disclosure relates to a method for manufacturing a coating film.

As a continuous process in a roll-to-roll system, the method of manufacturing the target coating film on a support body is known.

As a manufacturing method of a coating film, there exists a method of apply|coating the coating liquid for obtaining the target coating film on a support body, and drying the obtained coating liquid film, for example.

As an example of a method for producing a coating film, Patent Document 1 discloses that an ink-absorbing layer coating liquid containing inorganic fine particles and a water-soluble resin is applied to a continuously running web, followed by a drying step of drying the ink-absorbing layer Production of an inkjet recording sheet In the method, in the drying step, a method for producing a sheet for inkjet recording in which the distribution of the drying rate in the web width direction of the ink absorption layer is within 20% is disclosed.

Further, in Patent Document 2, inorganic fine particles are dispersed in the presence of a water-soluble polyvalent metal compound to obtain a dispersion (1), and separately, inorganic fine particles are dispersed in the presence of an organic cationic polymer to obtain a dispersion (2) , a method for producing a recording medium in which the obtained dispersions (1) and (2) are mixed, applied on a support, and dried.

Further, in Patent Document 3, a step of applying a negative electrode paste containing a negative electrode active material, a thickener, and a binder to the surface of a negative electrode current collector, and a negative electrode paste layer formed by applying the negative electrode paste to the surface of the negative electrode current collector, Equation 1: Disclosed is a method for manufacturing a negative electrode comprising a drying step of drying to satisfy (the surface temperature of the negative electrode paste layer)-(the temperature of the negative electrode current collector) ≤ 1°C.

Patent Document 1: Japanese Patent Laid-Open No. 2004-268392 Patent Document 2: Japanese Patent Application Laid-Open No. 2006-187883 Patent Document 3: Japanese Patent Application Laid-Open No. 2016-66460

For example, as in a continuous process in a roll-to-roll system, as a method of manufacturing a coating film on a support that is continuously conveyed, a step of applying a water-based coating liquid on a support with high thermal conductivity to form a coating liquid film; In the manufacturing method of the coating film which performs the process of drying a coating liquid film, a crack may generate|occur|produce in the width direction edge part of the obtained coating film.

Then, the problem to be solved by one embodiment of the present disclosure is made in view of the above circumstances, and a method of manufacturing a coating film on a support that is continuously conveyed (for example, a method using a continuous process in a roll-to-roll system) ) WHEREIN: It is providing the manufacturing method of the coating film which can suppress the crack which generate|occur|produces in the edge part of the width direction of a coating film.

Means for solving the said subject include the following embodiment.

<1> Step A of continuously conveying a long support having a thermal conductivity of 200 W/(m·K) or more and applying a water-based coating solution on the continuously conveyed support, and on the continuously conveyed support, in Step A Including the step B of drying the obtained coating solution film,

The manufacturing method of a coating film in which process B includes the constant constant drying step of the coating liquid film which satisfy|fills the following conditions (1) and (2).

Condition (1): A _(T0%) is the film surface temperature at a position 5 mm from the edge of the coating solution film in the width direction at the time T0% when constant constant drying is started, and the film surface temperature of the center portion in the width direction of the coating liquid film is B _(T0%) , and the film surface temperature at a position 5 mm from the width direction edge of the coating solution film at T90% when 90% of the constant drying time has elapsed is A _(T90%) , and the coating solution film When the film surface temperature of the central portion in the width direction of is B _(T90%) , ΔT[°C] obtained from the following formula (A) is -10°C<ΔT<0°C.

Formula (A) ΔT[℃]=(A _(T0%) -B _(T0%) )-(A _(T90%) -B _(90%) )

Condition (2): The average value of the film surface temperature A _(T0%) , the film surface temperature B _(T0%) , the film surface temperature A _(T90%) , and the film surface temperature B _(T90%) is 35°C or more.

<2> When the thickness at a position of 5 mm from the edge of the coating solution film in the width direction is At and the thickness of the center portion in the width direction of the coating solution film is Bt, the relationship of 0.9≤At/Bt≤1.1 is satisfied, <1 > The manufacturing method of the coating film as described in.

<3> The method for producing a coating film according to <1> or <2>, wherein the aqueous coating liquid is a coating liquid containing particles.

The manufacturing method of the coating film in any one of <1>-<3> whose thickness of the coating film after <4> process B is 40 micrometers or more.

ADVANTAGE OF THE INVENTION According to one Embodiment of this indication, in the method of manufacturing a coating film on the support body conveyed continuously, the manufacturing method of the coating film which can suppress the crack which generate|occur|produces in the width direction edge part of a coating film is provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows each process of the manufacturing method of the coating film of one Embodiment.
It is a schematic top view for demonstrating the film surface temperature of the coating liquid film formed on the support body.
3 is a graph for explaining the film surface temperature in the constant constant drying step.

Hereinafter, embodiment of the manufacturing method of a coating film is demonstrated. However, this invention is by no means limited to the following embodiment, In the range of the objective of this invention, a change can be added and implemented suitably.

In the present disclosure, the numerical range indicated by using "to" means a range including the numerical values described before and after "to" as the minimum and maximum values, respectively.

In the numerical range described step by step in the present disclosure, the upper limit or lower limit described in the predetermined numerical range may be substituted with the upper limit or lower limit of the numerical range described in another stepwise manner. In addition, in the numerical range described in this indication, you may substitute the value shown in the Example for the upper limit or lower limit described in a predetermined numerical range.

Each element in each drawing shown in this indication is not necessarily to an exact scale, Emphasis is placed on clearly showing the principle of this indication, and there are places where emphasis is placed on.

In addition, in each figure, the same code|symbol is attached|subjected to the component which has the same function, and overlapping description is abbreviate|omitted.

In this indication, the "width direction" refers to the direction orthogonal to the longitudinal direction of any one of a long support body, a coating solution film, and a coating film.

In the present disclosure, the term "width direction edge portion" refers to an edge portion in the width direction of the coating solution film or coating film, and when the coating solution film or the film surface of the coating film is viewed from above, the coating region (ie, the coating solution film or It is visually recognized as a boundary line between the formation part of a coating film) and a non-coated area|region (ie, the exposed part of a support body).

In the present disclosure, the "width direction edge" refers to a coating solution film or an edge portion in the width direction of the coating film, from the width direction edge portion (specifically, the boundary line between the coated area and the non-coated area) in the width direction to the central portion in the width direction. Points to the area up to 20 mm towards

In this indication, the combination of 2 or more preferable aspect or aspect is a more preferable aspect or aspect.

≪Method for Producing Coated Film≫

As described above, as a method of manufacturing a coating film on a support that is continuously conveyed, a process of forming a coating solution film by applying an aqueous coating solution on a support with high thermal conductivity, and drying the formed coating solution film. In the manufacturing method, a crack may generate|occur|produce in the width direction edge part of the obtained coating film.

As described above, the cracks in the width direction edge portion of the coating film use a support excellent in thermal conductivity, such as a metal, as a support for forming the coating film, and, as a coating liquid, a solvent or an aqueous dispersion medium in which the solvent or dispersion medium is substantially water. This is a phenomenon that occurs when a coating solution is used.

As a result of examining the above-described method for producing the coating film, the present inventors paid attention to the amount of change in the temperature difference between the center of the coating liquid film in the width direction and the edge portion in the width direction in the constant constant drying step, and this amount of change (the above conditions) By controlling (DELTA)T in (1), it discovered that the crack which generate|occur|produces in the width direction edge part of a coating film can be suppressed, and came to achieve this invention.

In the method for manufacturing a coating film according to the present embodiment, a long support having a thermal conductivity of 200 W/(m·K) or more is continuously conveyed, and a water-based coating solution is applied on the continuously conveyed support A, and on a continuously conveyed support. , Process B of drying the coating solution film obtained in step A, and step B includes a constant-modulus drying step of the coating solution film satisfying the following conditions (1) and (2).

Condition (1): A _(T0%) is the film surface temperature at a position 5 mm from the edge of the coating solution film in the width direction at the time T0% when constant constant drying is started, and the film surface temperature of the center portion in the width direction of the coating liquid film is B _(T0%) , and the film surface temperature at a position 5 mm from the width direction edge of the coating solution film at T90% when 90% of the constant drying time has elapsed is A _(T90%) , and the coating solution film When the film surface temperature of the central portion in the width direction of is B _(T90%) , ΔT[°C] obtained from the following formula (A) is -10°C<ΔT<0°C.

Formula (A) ΔT[℃]=(A _(T0%) -B _(T0%) )-(A _(T90%) -B _(90%) )

Condition (2): The average value of the film surface temperature A _(T0%) , the film surface temperature B _(T0%) , the film surface temperature A _(T90%) , and the film surface temperature B _(T90%) is 35°C or more.

According to the manufacturing method of the coating film which concerns on this embodiment, the crack which generate|occur|produces in the width direction edge part of a coating film can be suppressed.

On the other hand, in the manufacturing method of the coating film described in Patent Documents 1 to 3, no attention is paid to the amount of change in the temperature difference between the width direction center and the width direction edge portion of the coating liquid film in the constant constant drying step, and for cracks at the width direction end portions of the coating film no mention

Hereinafter, each process of the manufacturing method of the coating film of this embodiment is demonstrated.

First, an example of the manufacturing method of a coating film is demonstrated with reference to FIG.

As shown in FIG. 1, the water-based coating liquid is apply|coated by the coating means 20 when the front-end|tip is unwound and continuous conveyance of the wound long support body 10 is started (process A). By the process A, the coating liquid film by the water-based coating liquid is formed on the elongate support body.

Subsequently, the coating solution film is dried on the support body 10 by continuously conveying the support body 10 having the coating solution film formed in the step A through the drying means 30a and 30b (step B). By the process B, the coating liquid film on a long support body is dried, and a coating film is formed.

[Process A]

In the step A, a long support having a thermal conductivity of 200 W/(m·K) or more is continuously conveyed, and a water-based coating solution is applied on the continuously conveyed support.

Here, the aqueous coating solution refers to a coating solution in which the solvent (or dispersion medium) contained in the coating solution is substantially water. "The solvent (or dispersion medium) is substantially water" means allowing the inclusion of a solvent other than water introduced when using the solid content, and indicates that the proportion of water in the exclusive solvent (or total dispersion medium) is 90% by mass or more, , It is preferable that the ratio of water in the exclusive solvent (or all-dispersion medium) is 95 mass % or more, and it is especially preferable that the exclusive solvent (or all-dispersion medium) is water.

In addition, solid content refers to the component except a solvent (or a dispersion medium).

-Support-

The elongate support body used for this process is a support body whose thermal conductivity is 200 W/(m*K) or more. In addition, when the support used in this process is a support body of the multilayer structure containing, for example, metal foil and a resin film, the thermal conductivity as the whole support body should just be 200 W/(m*K) or more.

The upper limit of the thermal conductivity of the support is not particularly limited, and is, for example, 500 W/(m·K).

Specific examples of the support exhibiting the thermal conductivity include metal supports made of copper, aluminum, silver, gold, and alloys thereof.

Among these, a copper support body and an aluminum support body are preferably used from points, such as shape stability as a support body, usage history, etc.

The thermal conductivity of the support is measured as follows.

First, a support body is cut to the size suitable for the apparatus mentioned later, and the sample for a measurement is obtained. With respect to the obtained sample for measurement, the thermal diffusivity in the thickness direction is measured by the laser flash method using "LFA467" manufactured by NETZSCH. Next, the specific gravity of the sample for measurement is measured using a METTLER TOLEDO Co., Ltd. balance "XS204" (using a "solid specific gravity measurement kit"). In addition, using "DSC320/6200" of Seiko Instruments Co., Ltd., the specific heat of the sample for a measurement in 25 degreeC under the temperature rising condition of 10 degreeC/min is calculated|required using the software of DSC7. By multiplying the obtained thermal diffusivity by specific gravity and specific heat, the thermal conductivity of the sample for a measurement (ie, a support body) is computed.

What is necessary is just to set the thickness of a support body suitably from a viewpoint of applying to a roll-to-roll system.

It is preferable that they are 5 micrometers - 100 micrometers, and, as for the thickness of a support body, it is more preferable that they are 10 micrometers - 30 micrometers, for example.

What is necessary is just to set the width|variety and length of a support body suitably from a viewpoint applied to a roll-to-roll system, and the width|variety and length of the target coating film.

The thickness of the support body is measured as follows.

That is, using a contact-type thickness measuring device, measure the thickness of three points in the width direction of the support (that is, the position 5 mm from both edges in the width direction and the center portion in the width direction) at 3 points with an interval of 500 mm in the longitudinal direction. measure

The arithmetic mean value of the measured total of nine measured values is calculated|required, and let this be the thickness of a support body.

As a contact type thickness measuring device, S-2270 of Fuji Works is used, for example.

-Water-based coating solution-

The aqueous coating liquid used in this step is not particularly limited as long as it is a liquid containing water as a solvent (or dispersion medium) and a solid content as described above.

In addition to the component for obtaining the target coating film, the component etc. for improving application|coating suitability are contained in the solid content contained in an aqueous coating liquid.

Examples of the water contained in the aqueous coating solution include natural water, purified water, distilled water, ion-exchanged water, pure water, and ultrapure water (eg, Milli-Q water). In addition, Milli-Q water is ultrapure water obtained by the Milli-Q water production apparatus of Merck Millipore of Merck Corporation.

The content of water in the aqueous coating solution is not particularly limited, and for example, it is preferably 40 mass% or more, and more preferably 50 mass% or more, with respect to the total mass of the aqueous coating solution.

Although the upper limit of content of water should just be less than 100 mass %, for example, it is 90 mass % with respect to the total mass of a water-based coating liquid from a viewpoint of application|coating aptitude.

The aqueous coating liquid may contain particles as one of the solid content. That is, the coating liquid containing particle|grains may be sufficient as an aqueous coating liquid.

When an aqueous coating solution containing particles is used, since aggregation of particles is also added in the constant-modulus drying step, cracks tend to occur at the ends of the coating film in the width direction. However, by applying the manufacturing method of the coating film which concerns on this embodiment, even when it is a case where the aqueous coating liquid containing particle|grains is used, the crack of the width direction edge part of a coating film can be suppressed.

There will be no restriction|limiting in particular as long as a particle|grain is a granular material, Inorganic particle|grains may be sufficient, organic particle|grains may be sufficient, and composite particle|grains of an inorganic substance and an organic substance may be sufficient as it.

As an inorganic particle, the well-known inorganic particle applicable to the coating film made into the objective can be used.

Examples of the inorganic particles include particles of metals (alkali metals, alkaline earth metals, transition metals, etc., and alloys of these metals), particles of semimetals (such as silicon), or metal or semimetal compounds (oxides, hydroxides, particles of a nitride etc.), and particles of a pigment containing carbon black or the like.

Examples of the inorganic particles include particles of minerals such as mica, inorganic pigment particles, and the like.

As organic particle|grains, well-known organic particle|grains applicable to the target coating film can be used.

The organic particles are not particularly limited as long as they are particles of solid organic substances including resin particles and organic pigment particles.

As the composite particle of an inorganic substance and an organic substance, a composite particle in which inorganic particles are dispersed in a matrix of an organic substance, a composite particle in which the periphery of the organic particle is coated with an inorganic substance, a composite particle in which the periphery of the inorganic particle is coated with an organic substance, etc. can be heard

The particle|grains may be surface-treated for the objective, such as provision of dispersibility.

Moreover, it may become said composite particle by surface-treating.

There is no particular limitation on the particle size, specific gravity, usage mode (for example, the presence or absence of combined use, etc.) of the particles, and it is appropriately selected depending on the target coating film or conditions suitable for manufacturing the coating film. do.

There is no restriction|limiting in particular as content of the particle|grains in a water-based coating liquid, According to the conditions suitable for manufacturing a coating film, depending on the target coating film, According to the purpose of adding particle|grains, what is necessary is just to determine suitably.

There exists a tendency for the crack of the edge part of the width direction of a coating film to be conspicuous (that is, it is easy to visually recognize), so that many particle|grains are contained in an aqueous coating film. By applying the manufacturing method of the coating film which concerns on this embodiment, even if content of the particle|grains in an aqueous coating liquid is 50 mass % or more, for example, the crack of the width direction edge part of a coating film can be suppressed.

It does not restrict|limit especially as solid content contained in an aqueous coating liquid, Various components used in order to obtain the target coating film are mentioned.

Specifically, as the solid content contained in the aqueous coating solution, in addition to the above-mentioned particles, a binder component, a component contributing to the dispersibility of the particles, a polymerizable compound, a reactive component such as a polymerization initiator, a component for enhancing coating performance such as a surfactant, Other additives, etc. are mentioned.

-Thickness of coating film-

The thickness in particular of the coating solution film formed in this process is not restrict|limited, What is necessary is just to determine suitably according to the coating film made into the objective.

For example, the thickness of the coating solution film formed in this step is 0.8 ≤ when the thickness at a position of 5 mm from the edge of the coating solution film in the width direction is At, and the thickness of the central portion in the width direction of the coating solution film is Bt. It is preferable to satisfy the relationship of At/Bt≤2.5 (preferably 0.9≤At/Bt≤1.5, more preferably 0.9≤At/Bt≤1.1).

As described above, when the difference in thickness between the thickness At and the thickness Bt is small, that is, in the case of forming a coating solution film having a thickness close to uniform in-plane, by applying the method for manufacturing the coating film according to the present embodiment, The crack of the width direction edge part of a coating film can be suppressed effectively.

In addition, although the aspect which forms the coating liquid film of uniform thickness in surface is common, in the manufacturing method of the coating film which concerns on this embodiment, the thickness At and thickness Bt of the coating liquid film may differ.

When the thickness At and the thickness Bt of the coating solution film are different, the film surface temperature and the amount of change thereof in step B, which will be described later, also change due to the difference in thickness. Therefore, in the step B, ΔT may be controlled according to the change in the film surface temperature.

Thickness At and thickness Bt are measured as follows.

First, as the thickness At, an optical interference type thickness measuring device is used, one of the two width direction edges of the coating solution film is selected, and the coating solution film at a position of 5 mm from the selected edge part toward the width direction center part of the coating solution film The thickness is measured at three points at intervals of 500 mm in the longitudinal direction.

The arithmetic mean value of the measured values of three measured points is calculated|required, and let this be thickness At.

Moreover, as thickness Bt, the thickness of the center part in the width direction of the coating solution film is measured at three points at intervals of 500 mm in the longitudinal direction using an optical interference type thickness measuring device.

The arithmetic mean value of the measured three points|pieces is calculated|required, and let this be thickness Bt.

As the optical interference type thickness meter, for example, an infrared spectral interference type thickness meter SI-T80 manufactured by Keyence Corporation can be used.

-Coating width-

The coating width (that is, the width of the coating liquid film) in this step is not particularly limited, and the coating width in which cracks are likely to occur is applied to the width direction end of the produced coating film. From a viewpoint of suppressing the crack in the width direction edge part of a coating film, it is preferable that it is, for example, 30 mm or more, as for a coating width, it is more preferable that it is 50 mm or more, It is more preferable that it is 100 mm or more.

The upper limit of the coating width is the width of the support body.

When the coating solution film on the support body is formed, as the width of the non-coated region that is the distance from the width direction edge of the support body to the coating solution film (that is, the width of the exposed part of the support body), the effect of the method for producing the coating film according to the present embodiment is From a viewpoint of being easy to appear, it is preferable that it is respectively, for example, 2 mm or more, and it is more preferable that it is 5 mm or more in the width direction both ends.

Coating width is measured as follows.

That is, the film surface of the coating solution film is viewed from the top, and the width of the coating solution film is measured at three points with a ruler and an interval of 500 mm in the longitudinal direction.

The arithmetic mean value of the measured three points|pieces is calculated|required, and let this be coating width.

-apply-

A well-known application|coating means is applied to application|coating of the coating liquid in this process.

As a coating means (for example, the coating means 20 in FIG. 1), specifically, the curtain coating method, the dip coating method, the spin coating method, the printing coating method, the spray coating method, the slot coating method, the roll coating method A coating device using a method, a slide coating method, a blade coating method, a gravure coating method, a wire bar method, or the like is exemplified.

[Process B]

In the process B, the coating liquid film obtained in the process A is dried on the support body conveyed continuously.

And the process B includes the constant-modulus drying step of the coating liquid film which satisfy|fills the conditions (1) and (2) mentioned later.

Drying in this process points out until the coating liquid film formed in process A reaches|attains the target solid content concentration through a constant rate drying step and a decreasing rate drying step.

Here, "constant drying" is a form of drying in which the content of the solvent (or dispersion medium) in the coating liquid film decreases with time.

In general, the coating liquid film exhibits constant-rate drying from immediately after formation until a certain period of time passes, and then exhibits reduced-rate drying. About the time showing constant constant drying, it is described in the chemical engineering manual (pages 707-712, Maruzen Co., Ltd. publication, Showa 55 (1980) October 25), for example.

In the present disclosure, the change over time of the film surface temperature (film surface temperature B to be described later) of the central portion in the width direction of the formed coating liquid film is measured, and in the measurement of the film surface temperature immediately after application (immediately after the formation of the coating liquid film), the film surface temperature is A period showing a constant value (specifically, a period in which the temperature change of the film surface temperature is within ±5°C) is regarded as a "constant drying step".

Then, after the period in which the film surface temperature exhibits a constant value, the period in which the film surface temperature rises is regarded as a "falling rate drying step".

In addition, the film surface temperature is measured with a non-contact type radiation thermometer.

In process B, you may change drying temperature stepwise or continuously toward the conveyance direction of a coating liquid film. In this case, it is considered that the film surface temperature of the coating solution film is also influenced and changed. Therefore, in the step B, a period in which the film surface temperature of the coating liquid film changes to the same degree as the change amount of the drying temperature is included in the "period in which the film surface temperature shows a constant value".

That is, until the film surface temperature of a coating liquid film rises more than the change amount of a drying temperature, it is regarded as a constant constant drying step.

Drying in this process includes the constant-rate drying step which satisfy|fills conditions (1) and (2).

Hereinafter, conditions (1) and (2) are demonstrated.

-Condition (1)-

In the constant-modulus drying step of this process, the following condition (1) is satisfied.

Condition (1): A _(T0%) is the film surface temperature at a position 5 mm from the edge of the coating solution film in the width direction at the time T0% when constant constant drying is started, and the film surface temperature of the center portion in the width direction of the coating liquid film is B _(T0%) , and the film surface temperature at a position 5 mm from the width direction edge of the coating solution film at T90% when 90% of the constant drying time has elapsed is A _(T90%) , and the coating solution film When the film surface temperature of the central portion in the width direction of is B _(T90%) , ΔT[°C] obtained from the following formula (A) is -10°C<ΔT<0°C.

Formula (A) ΔT[℃]=(A _(T0%) -B _(T0%) )-(A _(T90%) -B _(90%) )

The film surface temperature A _(T0%) , the film surface temperature B _(T0%) , the film surface temperature A _(T90%) , and the film surface temperature B _(90%) in the formula (A) are described with reference to FIGS. 2 and 3 . do. Here, FIG. 2 is a schematic top view for demonstrating the film surface temperature of the coating liquid film formed on the support body. Moreover, FIG. 3 is a graph for demonstrating the film surface temperature in a constant-module drying step. Here, FIG.2 and FIG.3 has shown the case where the drying temperature is constant among process B.

As shown in FIG. 2 , in the coating solution film 40 formed on the support 10 , the film surface temperature A at a position 5 mm from the edge in the width direction indicated by LA, and the film surface temperature at the center portion in the width direction indicated by LB. The temporal change of B is measured, respectively, and the relationship between the film surface temperatures A and B and the elapsed time is graphed as shown in FIG. In addition, the film surface temperature A is the film surface temperature at a position of 5 mm from the selected edge part toward the width direction central part of the coating liquid film 40 from the selected edge part from the width direction edge part of the coating liquid film 40 which there are two. .

3 , in the graph, in the measurement of the film surface temperature B immediately after application (immediately after formation of the coating liquid film), the period during which the film surface temperature B shows a constant value (specifically, the temperature change of the film surface temperature is period within ±5°C) is regarded as the constant-rate drying phase. In addition, let the change point of the film surface temperature B at which the film surface temperature B changes to an increase as the end point of the constant constant drying step (T100% in FIG. 3). In addition, as for the change point, the straight line (dotted line x in FIG. 3) extending the membrane surface temperature B in the period showing a constant value to the elapsed time side (right side in FIG. 3), and the gradient of the membrane surface temperature B) It is obtained from the intersection of the tangent line (dotted line y in FIG. 3) drawn at the point where .

And let the period from the start point of the period in which the film surface temperature B shows a constant value to the change point of the film surface temperature B be constant constant drying time.

Then, the starting point of the period in which the film surface temperature B shows a constant value is referred to as the "time of T0% constant constant drying", and the entire period (i.e., T100% in FIG. 3) from the beginning to the end of this period. The point at which 90% of the constant rate drying time has passed) is referred to as "the time of T90% at which 90% of the constant rate drying time has passed".

Next, from the graph shown in Fig. 3, the film surface temperature A _(T0%) and the film surface temperature B _(T0%) at the T0% time point when constant constant drying is started, and 90% of the constant constant drying time has passed The film surface temperatures A _(T90%) and B _(T90%) at the time of T90% are determined.

By substituting the values of the film surface temperature A _(T0%) , the film surface temperature B _(T0%) , the film surface temperature A _(T90%) , and the film surface temperature B _(T90%) obtained in this way into the above formula (A) , to find ΔT.

DELTA T calculated|required as mentioned above needs to be more than -10 degreeC and less than 0 degreeC.

Since the film surface temperature B in the central part in the width direction in the coating liquid film 40 as shown in FIG. 2 is not easily influenced by the thermal conductivity of a support body, it is hard to see an increase with time. On the other hand, the film surface temperature A at a position 5 mm from the edge in the width direction of the coating solution film 40 is easily affected by the support exposed in the non-coated area, and even in the constant constant drying stage, an increase with time is seen. There are cases.

In the constant-modulus drying step, if the membrane temperature A significantly increases with time, ΔT[°C] obtained from the formula (A) does not satisfy -10°C<ΔT<0°C.

As described above, in the constant-modulus drying step, if a significant increase with time of the film surface temperature A is observed, the drying proceeds only at the width direction end of the coating solution film 40, so the width direction end portion of the coating film obtained through this step is cracked. It is presumed that this will occur.

On the other hand, when ΔT[°C] satisfies -10°C<ΔT<0°C, it means that the remarkable rise of the film surface temperature A in the coating solution film 40 with the passage of time is suppressed.

That is, if the significant rise of the film surface temperature A with the passage of time is suppressed, it is thought that drying proceeds only at the width direction end of the coating solution film 40 is suppressed. cracking is suppressed.

ΔT[°C] may be -8°C<ΔT<0°C. ΔT[°C] may be -6°C<ΔT<0°C. ΔT[°C] may be -4°C<ΔT<0°C.

-Condition (2)-

In the constant constant drying step of this process, the following condition (2) is satisfied.

Condition (2): The average value of the film surface temperature A _(T0%) , the film surface temperature B _(T0%) , the film surface temperature A _(T90%) , and the film surface temperature B _(T90%) is 35°C or more.

The values of the film surface temperature A _(T0%) , the film surface temperature B _(T0%) , the film surface temperature A _(T90%) , and the film surface temperature B _(T90%) may be obtained from a graph as shown in FIG. 3 , respectively. Here, the average value of the film surface temperature A _(T0%) , the film surface temperature B _(T0%) , the film surface temperature A _(T90%) , and the film surface temperature B _(T90%) is the arithmetic average value of the four values obtained from the graph. .

When the average value of the film surface temperature in the constant constant drying step is 35° C. or higher, it is easily affected by the thermal conductivity of the support exposed to the non-coated region, and in the constant constant drying step, the film surface temperature A rises with time easy to see

That is, condition (2) has shown the condition in which the crack of the width direction edge part of a coating film is easy to generate|occur|produce.

In the manufacturing method of the coating film which concerns on this embodiment, even if condition (2) is satisfied, since condition (1) described above is also satisfied, the crack which generate|occur|produces in the edge part of the width direction of the coating film obtained through this process is suppressed. .

As long as it does not deviate from the meaning of this indication, the upper limit of the said average value of the film surface temperature in a constant-module drying step is not restrict|limited. The upper limit of the average value of the film surface temperature in the constant-rate drying step may be, for example, 90°C, 80°C, 70°C, 60°C, 50°C or 40°C.

-dry-

In this process, a well-known drying means is applied to drying of a coating liquid film.

As a drying means (for example, drying means 30a and 30b in FIG. 1), an oven, a hot air machine, an infrared (IR) heater, etc. are mentioned specifically,.

In particular, in the present step, the drying means for satisfying the conditions (1) and (2), particularly the drying means for controlling ΔT, include the following means.

・Using a warm air blower, the wind speed of the warm air blown to the coating solution film and the wind speed of the warm air blown to the non-coated region (exposed part of the support body) of the coating solution film are changed (for example, the wind speed of the warm air blown to the coating solution film) In comparison, the wind speed of the warm air blown to the non-coated area (exposed portion of the support) is reduced).

Using a warm air blower, the temperature of the warm air sprayed to the coating liquid film and the temperature of the warm air sprayed to the non-coated area (exposed part of the support) are changed (for example, compared to the temperature of the warm air sprayed to the coating liquid film, The temperature of the warm air blown to the non-coated area (exposed part of the support) is lowered (or the warm air blown to the non-coated area (exposed part of the support) is a cold air below room temperature)).

The drying means for satisfying the above conditions (1) and (2), especially the drying means for controlling ΔT, may be applied immediately after the coating solution film is formed in step A, or may be applied from the constant constant drying step.

In addition, it is preferable that the drying means for satisfying the above conditions (1) and (2), especially the drying means for controlling ΔT, continue during the constant constant drying step (that is, from the time point T0% to the time point T100%). do.

In addition, as another means for satisfying the conditions (1) and (2), particularly, other means for controlling ΔT, the following means are mentioned.

· Water of the same thickness as that of the coating solution film is applied to the non-coated area of the coating solution film (that is, the support body is not exposed in the non-coated area of the coating solution membrane).

- The non-coated area of the coating solution film is not formed or made small (for example, the shortest distance from both ends of the support in the width direction to both ends of the coating solution film is 2 mm or less).

When employing these means, from the viewpoint of satisfying the condition (2), and from the viewpoint of controlling the drying rate, it is preferable to use together the means for blowing warm air from a hot air blower to the coating solution film.

As for said drying means and various means for satisfy|filling said conditions (1) and (2), only one may be used and may be used combining two or more.

In addition, the drying means, drying conditions, etc. in a constant rate drying step and a decreasing rate drying step may be same or different. In addition, if the constant-rate drying step that satisfies the above conditions (1) and (2) is passed, even if the drying means, drying conditions, etc. in the reduced-rate drying step are changed, cracks occurring at the edge in the width direction are hardly affected. .

As mentioned above, a coating film is formed on a support body by passing through the process B.

The thickness in particular of the coating film obtained through process B is not restrict|limited, What is necessary is just thickness according to the objective, a use, etc.

In the manufacturing method of the coating film which concerns on this embodiment, it is preferable to set it as 40 micrometers or more, as for the thickness of a coating film, it is more preferable to set it as 50 micrometers or more, It is more preferable to set it as 60 micrometers or more. Compared with the conventional manufacturing method of a coating film, in the manufacturing method of the coating film which concerns on this embodiment, even if the thickness of a coating film becomes large, it is hard to generate|occur|produce the crack of the width direction edge part of a coating film.

There is no restriction|limiting in particular as for the upper limit of the thickness of a coating film, Although what is necessary is just to be decided according to a use, It is 300 micrometers, for example.

The measurement of the thickness of the coating film is the same as the measurement of the thickness of the coating liquid film.

[Other processes]

At least one of before the process A and after the process B. WHEREIN: You may have another process as needed.

There is no restriction|limiting in particular as another process, The pre-processing process performed before application of a coating solution film, the post-processing process performed with respect to the formed coating film according to the use of a coating film, etc. are mentioned.

Specific examples of the other steps include a step of surface-treating the support, a step of curing the coating film, a step of compressing the coating film, a step of cutting the coating film, a step of peeling the support from the coating film, and the like.

Since the manufacturing method of the coating film which concerns on this embodiment is a method of manufacturing a coating film on the support body conveyed continuously, it is suitable for manufacture of the coating film of the use by which high productivity is requested|required.

Example

Hereinafter, the present invention will be more specifically described by way of Examples. The material, usage amount, ratio, detail of each process, etc. shown in the following examples can be suitably changed, unless it departs from the meaning of this invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

In addition, all "parts" are based on mass.

<Preparation of support>

An aluminum support body 1 (thermal conductivity: 230 W/(m·K)) having a width of 220 mm, a thickness of 20 μm, and a length of 300 m was prepared (abbreviated as AL1).

An aluminum support body 2 (thermal conductivity: 230 W/(m·K)) having a width of 203 mm, a thickness of 20 μm, and a length of 300 m was prepared (abbreviated as AL2).

<Preparation of water-based coating solution>

[Preparation of water-based coating solution A]

The following components were mixed to prepare an aqueous coating liquid A.

・Polyvinyl alcohol: 58 parts

(CKS-50: saponification degree 99 mol%, polymerization degree 300, Nippon Kosei Chemical Co., Ltd.)

・Daichi High School Seiyaku Co., Ltd. Cellogen PR: 24 copies

・Surfactant (Nippon Emulsion Co., Ltd., Emalex 710): 5 parts

・Aqueous product of Art Pearl J-7P prepared by the following method: 913 parts

(Water product of Art Pearl J-7P)

In 74 parts of pure water, 3 parts of Emalex 710 (Nippon Emulsion Co., Ltd., nonionic surfactant) and 3 parts of sodium carboxymethylcellulose are added and dissolved. To the obtained aqueous solution, 20 parts of Art Pearl (registered trademark) J-7P (Negami Kogyo Co., Ltd., silica composite cross-linked acrylic resin fine particles) were added, and 10,000 were added with Ace Homogenizer (Nippon Seiki Seisakusho). It dispersed at rpm (revolutions per minute; hereinafter the same.) for 15 minutes to obtain an aqueous product of Art Pearl J-7P (particle concentration: 20% by mass).

The true specific gravity of the silica composite crosslinked acrylic resin fine particles in the obtained aqueous product was 1.20, and the average particle diameter was 6.5 µm.

[Preparation of water-based coating solution B]

The following components were mixed and stirred with a dissolver (2000 rpm, 30 minutes) to prepare an aqueous coating solution B (dispersion A: dispersion B = 25:75). The viscosity of the aqueous coating solution B was 20 mPa·s, and the average particle diameter of the particles was 0.108 μm.

Dispersion A prepared by the following method: 132.1 parts

Dispersion B prepared by the following method: 396.2 parts

・Boric acid (crosslinking agent): 2.94 parts

-Polyvinyl alcohol (7.3 mass % aqueous solution): 230.7 parts

(Kurare Co., Ltd., PVA 235, saponification degree 88%, polymerization degree 3500)

Diethylene glycol monobutyl ether: 2.7 parts

(Beautycenol 20-P, KH Neochem Co., Ltd.)

・Ion-exchanged water: 93.5 parts

Polyoxyethylene lauryl ether (surfactant): 0.49 parts

(10% by mass aqueous solution of emulgen 109P, HLB value 13.6, Kao Corporation)

・Ethanol: 41.4 parts

(Preparation of dispersion A)

After mixing and ultrasonically dispersing the following components, the dispersion was heated to 30° C. and maintained for 8 hours to prepare a dispersion A.

· Vapor method silica fine particles (inorganic fine particles): 299.6 parts

(AEROSIL 300SF75, Nippon Aerosil Co., Ltd.)

・Ion exchanged water: 1400 parts

・Alpine 83 (40.0 mass % aqueous solution): 300 parts

(Dispersant, Daimei Chemical High School Co., Ltd.)

(Preparation of dispersion B)

After mixing and ultrasonically dispersing the following components, the dispersion was heated to 30° C. and maintained for 8 hours to prepare a dispersion B.

· Vapor method silica fine particles (inorganic fine particles): 225.2 parts

(AEROSIL 300SF75, Nippon Aerosil Co., Ltd.)

・Ion-exchanged water: 1185 parts

- Cationic polymer A (25 mass % aqueous solution) of the following structure: 90 parts

[Formula 1]

[Example 1]

With the apparatus comprised as shown in FIG. 1, the water-based coating liquid A was apply|coated on the aluminum support body 1, the coating liquid film was formed, the formed coating liquid film was dried, and the coating film was obtained.

Specifically, the water-based coating liquid A was applied on a support to be continuously conveyed (step A). The coating width and thickness of the formed coating solution film are as having described in Table 1.

Then, hot air was blown using a warm air blower, and the coating solution film was dried using the ΔT control means shown in Table 1 (Step B).

In addition, blowing of the warm air using the hot air machine and drying by the ΔT control means were continued during the constant constant drying step (ie, from the time point T0% to the time point T100%). In the subsequent drying step at the rate of reduction, the blowing of the warm air and drying by the ΔT control means were continued.

Moreover, the conveyance speed of the support body in process A and process B was 20 m/min.

As mentioned above, the coating film was formed through the process A and the process B.

[Examples 2-6]

Except having changed the specific means of drying the coating liquid film in process B like Table 1, it carried out similarly to Example 1, and formed the coating film.

In addition, in Example 4, the aluminum support body 2 was used instead of the aluminum support body 1.

[Examples 7-13]

A coating film was formed in the same manner as in Example 1, except that the coating width of the coating solution film formed in the step A and the thickness of the coating solution film were appropriately changed as described in Table 1.

[Examples 14-19]

Except having changed the aqueous coating liquid A into the aqueous coating liquid B, it carried out similarly to each of Examples 1-6, and formed the coating film.

[Comparative Examples 1-4]

In step B, in addition to the coating solution film, the non-coated area of the coating solution film was also blown with the same warm air as the coating solution film, and the same as in each of Examples 1, 5, 6, and 14, except that the ΔT control means was not employed. and a coating film was formed.

[Reference example]

Instead of the aluminum support, a polyethylene terephthalate (PET) support (thermal conductivity: 0.3 W/(m·K)) having a width of 220 mm, a thickness of 38 µm, and a length of 300 m is used, and in step B, in addition to the coating solution film, coating A coated film was formed in the same manner as in Example 1, except that the non-coated region of the liquid film was also blown with the same warm air as that of the coating liquid film, and the ΔT control means was not employed.

[Measurement of film surface temperature, calculation of ΔT]

With respect to the coating solution films formed in the above Examples and Comparative Examples, by the method described above, the film surface temperature A _(T0%) , the film surface temperature B _(T0%) , the film surface temperature A _(T90%) , and the film surface temperature B _(T90% ) ₎ to calculate ΔT.

The obtained values are shown in Table 1.

[Evaluation of cracks at the edge of the coating film in the width direction]

About the coating film formed by the said Example and the comparative example, 1 m of arbitrary locations were cut out in the longitudinal direction, and the measurement sample was obtained.

The presence or absence of the crack which generate|occur|produces in the width direction edge part (ie, the area|region from the width direction edge part of a coating film toward the width direction center part of a coating film to 20 mm) of the obtained measurement sample was visually observed and confirmed.

A result is shown in Table 1.

[Table 1]

As is clear from Table 1, according to the manufacturing method of the coating film of an Example, it turns out that the coating film by which the crack of the width direction edge part was suppressed is formed.

As for the indication of Japanese Patent Application No. 2020-068517 for which it applied on April 6, 2020, the whole is taken in into this specification by reference. All documents, patent applications, and technical standards described in this specification are hereby incorporated by reference to the same extent as if each document, patent application, and technical standard were specifically and individually incorporated by reference. do.

10 long support
20 potter's means
30a drying means
30b drying means
40 Coating solution film
5 mm from the edge of the LA coating solution in the width direction
Center part in the width direction of the LB coating solution film
A film surface temperature at a position 5 mm from the edge of the coating solution film in the width direction
B Film surface temperature of the central part in the width direction of the coating solution film
Time at which T0% constant rate drying begins
When the T100% constant rate drying is finished
x A straight line extending to the elapsed time side of the membrane surface temperature B in the period showing a constant value
The tangent line drawn at the point where the gradient of temperature B is maximum when y is blocked.

Claims (4)

A step A of continuously conveying a long support having a thermal conductivity of 200 W/(m·K) or more, and applying a water-based coating solution on the continuously conveyed support;
step B of drying the coating solution film obtained in step A on a support that is continuously conveyed;
The manufacturing method of a coating film in which process B includes the constant constant drying step of the coating liquid film which satisfy|fills the following conditions (1) and (2).
Condition (1): A _(T0%) is the film surface temperature at a position 5 mm from the edge of the coating solution film in the width direction at T0% when constant constant drying is started, and the film surface temperature of the center portion in the width direction of the coating liquid film is B _(T0%) , and the film surface temperature at a position 5 mm from the edge in the width direction of the coating solution film at the time of T90% after 90% of the constant drying time has elapsed as A _(T90%) , the coating solution film When the film surface temperature of the central portion in the width direction of is B _(T90%) , ΔT obtained from the following formula (A) is -10°C<ΔT<0°C.
Formula (A) ΔT[℃]=(A _(T0%) -B _(T0%) )-(A _(T90%) -B _(90%) )
Condition (2): The average value of the film surface temperature A _(T0%) , the film surface temperature B _(T0%) , the film surface temperature A _(T90%) , and the film surface temperature B _(T90%) is 35°C or higher. The method according to claim 1,
A method for producing a coating film, wherein the relationship of 0.9≤At/Bt≤1.1 is satisfied when the thickness at a position of 5 mm from the edge of the coating film in the width direction is At and the thickness of the central portion in the width direction of the coating film is Bt. The method according to claim 1 or 2,
The method for producing a coating film, wherein the aqueous coating liquid is a coating liquid containing particles. 4. The method according to any one of claims 1 to 3,
The manufacturing method of a coating film whose thickness of the coating film after process B is 40 micrometers or more.

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