JP2005249287A - Drying method - Google Patents

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JP2005249287A
JP2005249287A JP2004060227A JP2004060227A JP2005249287A JP 2005249287 A JP2005249287 A JP 2005249287A JP 2004060227 A JP2004060227 A JP 2004060227A JP 2004060227 A JP2004060227 A JP 2004060227A JP 2005249287 A JP2005249287 A JP 2005249287A
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coating
coating film
drying
support
viscosity
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Toshiyuki Komura
俊行 香村
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Konica Minolta Medical and Graphic Inc
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Konica Minolta Medical and Graphic Inc
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a drying method for preventing irregular blow off in a drying process independently of the type of embrocation. <P>SOLUTION: The drying method comprises applying the embrocation on a band support being continuously carried to form a coating and then blowing hot air to the band support having the coating and being carried in a drying zone to dry the coating. Herein, the coating is dried in the conditions that a relationship among the density, viscosity and thickness of the coating, the velocity of hot air on the coating and a time required for drying the coating satisfies the following expression (1): 0<k∫(v×h×ρ/μ)dt/t≤0.05, where v is the velocity [m/s] of the hot air on the coating, h is the thickness [m] of the coating, ρ is the density [kg/m3] of the coating, μ is the viscosity [Pa s] of the coating, t is a time [s] required for drying the coating, and k is a constant determined by the type of the coating. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、連続的に搬送される支持体上に塗布液を塗布して形成された塗膜に乾燥風を吹き付けることにより塗膜を乾燥させる乾燥方法に関する。   The present invention relates to a drying method in which a coating film is dried by spraying a drying air onto a coating film formed by applying a coating liquid onto a continuously conveyed support.

従来より連続走行している帯状支持体に塗布液を塗布する方法としては、各種提案されており、例えばこれらの各種塗布方式については、Edward Cohen、Edgar Gutoff著「Modern Coating and Drying Technology」に述べられている。又、単層塗布のみならず、スライドコーターやエクストルージョンコーターやカーテンコーターなど複数のスリットを有するコーティングダイを用いることにより、同時に重層塗布することも知られている。   Various methods have been proposed as a method for applying a coating solution to a belt-like support that is continuously running. For example, these coating methods are described in Edward Cohen and Edgar Gutoff, “Modern Coating and Drying Technology”. It has been. In addition to single layer coating, it is also known to simultaneously perform multilayer coating by using a coating die having a plurality of slits such as a slide coater, an extrusion coater and a curtain coater.

写真用フィルム・印画紙等の写真感光材料や写真製版材料、磁気記録材料、熱現像感光材料、感圧記録材料等の記録材料、易接着性、易滑性、ガス遮断性、防湿性、制電性、インク受容性等の機能を付与する材料は、コーターから有機溶剤系又は水系の塗布液を連続搬送する帯状支持体の上に塗布して塗膜面を形成し、その後、塗膜を有する帯状支持体は、次工程である乾燥ボックスを有する乾燥装置で乾燥することで製造されている。乾燥ボックスは1つでも良いが通常複数個のボックスを直列に配置し、段階的に乾燥条件を変更してゆくことでより効率的な乾燥を行うことが一般的である。   Photographic materials such as photographic film and photographic paper, photoengraving materials, magnetic recording materials, photothermographic materials, pressure sensitive recording materials, etc., easy adhesion, slipperiness, gas barrier properties, moisture resistance, control A material imparting functions such as electric conductivity and ink acceptability is applied on a belt-like support that continuously conveys an organic solvent-based or aqueous coating solution from a coater to form a coating film surface, and then the coating film is formed. The belt-shaped support body is manufactured by drying with a drying apparatus having a drying box as the next step. Although there may be one drying box, it is general to perform more efficient drying by arranging a plurality of boxes in series and changing the drying conditions step by step.

又、連続走行している支持体に塗布液を塗布した後乾燥する方法としては、先述のEdward Cohen、 Edgar Gutoff著「Modern Coating and Drying Technology」に述べられている各種の方法が提案されてきた。最も一般的には乾燥ボックスに温風を供給し、その温風によって塗膜を乾燥させ、気化した溶媒を気流とともに系外へ排出する方法である。また、可燃性有機溶剤を用いる場合にはエアの代わりに不活性ガスを供給し、実質的に爆発のない安全な仕組みにする装置も知られている。本発明の適用は、温風によって乾燥させる方式、装置であれば、エアであっても、不活性ガスであっても特に限定されない。   In addition, as a method of drying after applying a coating liquid to a continuously running support, various methods described in Edward Cohen and Edgar Gutoff's “Modern Coating and Drying Technology” have been proposed. . The most general method is to supply warm air to a drying box, dry the coating film with the warm air, and discharge the vaporized solvent to the outside of the system together with the air current. In addition, when a flammable organic solvent is used, an apparatus that supplies an inert gas instead of air to make a safe mechanism substantially free of explosion is also known. The application of the present invention is not particularly limited as long as it is a system or apparatus that is dried by warm air, whether it is air or an inert gas.

乾燥工程は、塗布直後の塗膜面を加熱した雰囲気、温風が当たる雰囲気にさらすために、塗膜面の性状に影響を与える重要な工程となっている。一般的に乾燥工程における塗膜面に与える問題として温風が当たることにより塗膜表面が乱され、表面の平滑度を失い、いわゆる吹かれムラが生じ、最終的な塗膜品質に影響を与えることが知られている。   The drying process is an important process that affects the properties of the coating film surface in order to expose the coating film surface immediately after coating to a heated atmosphere or an atmosphere to which hot air is applied. Generally, as a problem on the coating surface in the drying process, the surface of the coating film is disturbed by hot air, and the smoothness of the surface is lost, so-called uneven spraying occurs, affecting the final coating film quality. It is known.

これら従来の乾燥方法の欠点を改善するため、使用する塗布液の粘度、又は塗膜面に対する乾燥風の面から検討がなされて来た。例えば、使用する塗布液の粘度に関しては、2種以上の塗布液を連続的に走行するウエブに多層同時塗布する時に、塗布液の剪断速度違いでの剪断粘度比を規定して塗布液の吹かれ耐性を上げることにより、塗布後の流れムラや乾燥ムラの抑制を行う方法が知られている(特許文献1を参照。)。   In order to improve the drawbacks of these conventional drying methods, investigations have been made from the viewpoint of the viscosity of the coating solution used or the drying air with respect to the coating surface. For example, regarding the viscosity of the coating solution to be used, when two or more types of coating solutions are applied simultaneously to a continuously running web, the viscosity of the coating solution is regulated by specifying the shear viscosity ratio at different shear rates of the coating solution. A method of suppressing flow unevenness after coating and drying unevenness by increasing the resistance is known (see Patent Document 1).

又、塗膜面に対する乾燥風に関しては、温度を制御した空気を塗布面へ吹き付けることにより塗膜を乾燥する乾燥工程で、塗布後の時間と塗布面に到達する乾燥風の風速との関係を規定することで、塗布後の乾燥工程における吹かれムラ等の故障を回避する方法が知られている(特許文献2を参照。)。   In addition, regarding the drying air for the coating surface, the relationship between the time after coating and the wind speed of the drying air reaching the coating surface in the drying process of drying the coating film by blowing air with controlled temperature to the coating surface. By prescribing, a method for avoiding failures such as blown unevenness in the drying process after coating is known (see Patent Document 2).

特許文献1及び特許文献2に記載の方法で乾燥工程における吹かれムラの発生は、ある程度抑制されるのであるが、塗布液の特性に応じた乾燥風の条件及び乾燥風の条件に応じた塗布液の特性が十分となっていないため、乾燥風の条件及び塗布液の種類によっては吹かれムラが発生し、乾燥工程における吹かれムラ対策は十分となっていない。   Although the occurrence of blown unevenness in the drying process is suppressed to some extent by the methods described in Patent Literature 1 and Patent Literature 2, the drying air condition according to the characteristics of the coating liquid and the coating according to the drying air condition are applied. Since the characteristics of the liquid are not sufficient, blowing unevenness occurs depending on the condition of the drying air and the type of coating liquid, and countermeasures against blowing unevenness in the drying process are not sufficient.

この様な状況から、塗布液の種類に影響されることがなく、乾燥工程における吹かれムラが発生しない乾燥方法の開発が望まれている。
特開平9−108615号公報 特開2000−329463号公報
Under such circumstances, it is desired to develop a drying method that is not affected by the type of coating liquid and that does not cause uneven spraying in the drying process.
JP-A-9-108615 JP 2000-329463 A

本発明は、上記状況に鑑みなされたものであり、その目的は、塗布液の種類に影響されることがなく、乾燥工程における吹かれムラが発生しない乾燥方法を提供することである。   The present invention has been made in view of the above situation, and an object of the present invention is to provide a drying method that is not affected by the type of coating liquid and that does not cause uneven spraying in the drying process.

本発明の上記目的は、下記の構成により達成された。   The above object of the present invention has been achieved by the following constitution.

(請求項1)
連続的に搬送する帯状支持体上に塗布液を塗布して塗膜を形成した後、該塗膜を有する帯状支持体を搬送しながら乾燥ゾーンで温風を吹き付けることにより前記塗膜を乾燥する乾燥方法において、
前記塗膜の密度と、粘度と、厚さと、
前記塗膜上の該温風の風速と、
前記塗膜の乾燥に要する時間との関係が式1)を満たす条件で、前記塗膜を乾燥することを特徴とする乾燥方法。
(Claim 1)
After coating the coating solution on the belt-like support that is continuously conveyed to form a coating film, the coating film is dried by blowing warm air in the drying zone while conveying the belt-like support having the coating film. In the drying method,
The density, viscosity, thickness of the coating film,
Wind speed of the warm air on the coating film;
A drying method characterized in that the coating film is dried under the condition that the relationship with the time required for drying the coating film satisfies the formula 1).

式1)
0<k∫(v×h×ρ/μ)dt/t≦0.05
式中 v:塗膜上の温風の風速[m/s]
h:塗膜の厚さ[m]
ρ:塗膜の密度[kg/m3
μ:塗膜の粘度[Pa・s]
t:塗膜の乾燥に要する時間[s]
k:塗膜の種類により決まる定数
上記課題を達成するために、発明者らは鋭意検討を加えた結果、連続的に搬送する帯状支持体上に塗布液を塗布して塗膜を形成した後、塗膜を有する帯状支持体を搬送しながら乾燥ゾーンで温風を吹き付けることにより塗膜を乾燥する時に発生する吹かれムラは、乾燥が始まってから一定の時間の間に塗膜面に吹き付けられた温風により塗膜面が動いてしまうことにより発生し、温風が弱くても塗膜の状態によっては吹かれムラは発生する場合もあるし、温風が強くても塗膜の状態によっては吹かれムラは発生しない場合があることが判明した。
Formula 1)
0 <k∫ (v × h × ρ / μ) dt / t ≦ 0.05
In the formula, v: the speed of warm air on the coating film [m / s]
h: thickness of coating film [m]
ρ: Density of coating film [kg / m 3 ]
μ: Viscosity of coating film [Pa · s]
t: Time required for drying the coating film [s]
k: Constant determined by the type of coating film In order to achieve the above-mentioned problems, the inventors have intensively studied, and as a result, after forming the coating film by coating the coating liquid on the belt-like support that is continuously conveyed The blown unevenness that occurs when the coating film is dried by blowing warm air in the drying zone while transporting the belt-like support having the coating film is sprayed on the coating film surface for a certain period of time after the drying starts. It occurs when the surface of the coating moves due to the warm air generated, and even if the warm air is weak, it may be blown depending on the state of the coating, and unevenness may occur even if the warm air is strong. It has been found that there is a case where unevenness does not occur in some cases.

何故、乾燥が始まってから一定の時間の間に吹かれムラが発生するのか、発明者らは更に鋭意検討を加えた結果、温風を吹き付けられることによる塗膜面の動きは、塗膜面上の温風の速さと形成された塗膜の物理化学特性との間に一定の関係があると推定した。   As a result of further diligent investigations, the inventors conducted further investigations as to why unevenness occurs during a certain period of time after drying began. It was estimated that there was a certain relationship between the speed of the hot air above and the physicochemical properties of the coating film formed.

これらに対して、発明者らは更に鋭意検討を加えた結果、形成された塗膜を動き易くしている塗膜中の溶媒量と、塗膜面の物理化学的特性を支配している塗布液の物理化学的特性と、形成された塗膜の厚さと、塗膜面上の温風の早さとの間に一定の関係持たせることが有効であることが判明し本発明に至った次第である。   In contrast, as a result of further diligent studies, the inventors have determined that the amount of solvent in the coating film that makes the formed coating film easy to move, and the coating that governs the physicochemical properties of the coating film surface. As soon as it has been found that it is effective to have a certain relationship between the physicochemical properties of the liquid, the thickness of the coating film formed, and the speed of hot air on the coating surface, the present invention has been achieved. It is.

塗布液の種類に影響されることがなく、乾燥工程における吹かれムラが発生しない乾燥方法を提供することが出来、常に安定した塗布・乾燥が可能となり、吹かれムラのない製品を製造することが可能となった。   It is possible to provide a drying method that is not affected by the type of coating solution and does not cause uneven spraying in the drying process, and can always apply and dry stably and produce products that are free from uneven spraying. Became possible.

本発明の実施の形態を図1を参照して説明するが、本発明はこれに限定されるものではない。   An embodiment of the present invention will be described with reference to FIG. 1, but the present invention is not limited to this.

図1は従来の温風吹き出し方式の乾燥ボックスを持つ乾燥装置を用いた乾燥方法の一例を示す概略図である。図1の(a)は複数の温風吹き出し方式の乾燥ボックスを連続的に繋げた乾燥ゾーンを有する乾燥装置を用い、塗布から乾燥までを示す概略図である。図1の(b)は図1の(a)に示される乾燥装置をコーター側から見た時の乾燥ボックス内の乾燥風の流れを示す模式図である。   FIG. 1 is a schematic view showing an example of a drying method using a drying apparatus having a conventional hot air blowing type drying box. FIG. 1 (a) is a schematic view showing the process from application to drying using a drying apparatus having a drying zone in which a plurality of hot air blowing type drying boxes are continuously connected. FIG. 1B is a schematic diagram showing the flow of the drying air in the drying box when the drying device shown in FIG. 1A is viewed from the coater side.

図中、1はバックロール2で保持され、連続搬送する帯状支持体3に塗布液を塗布するコーターを示す。4a〜4cは塗膜を有する帯状支持体3aの搬送(搬送方向は図中の矢印方向)を支持する支持ロールを示す。5は塗膜を有する帯状支持体3aを乾燥する乾燥装置を示す。乾燥装置5は加熱空気により乾燥するエアーモード乾燥方式の乾燥装置、加熱不活性ガスにより乾燥するイナート乾燥方式の乾燥装置のいずれでもかまわない。乾燥装置5は乾燥条件を個別に制御することが可能となっている乾燥ボックス501a、501bを連続的に繋げた乾燥ゾーンを有している。更に詳しくは、乾燥ボックス501aの塗膜を有する帯状支持体3aの入り口506から乾燥ボックス501bの出口507の間を乾燥ゾーンという。乾燥ボックスの数は特に限定はなく、乾燥する塗膜を有する帯状支持体3aの塗膜厚、搬送速度、乾燥温度、乾燥風量等により適宜選択することが可能である。本図では乾燥ボックスが2室の場合を示している。   In the figure, reference numeral 1 denotes a coater that is held by a back roll 2 and applies a coating solution to a belt-like support 3 that is continuously conveyed. 4a-4c shows the support roll which supports conveyance (the conveyance direction is the arrow direction in a figure) of the strip | belt-shaped support body 3a which has a coating film. Reference numeral 5 denotes a drying device for drying the belt-like support 3a having a coating film. The drying device 5 may be either an air mode drying type drying device that dries with heated air or an inert drying type drying device that dries with a heated inert gas. The drying device 5 has a drying zone in which drying boxes 501a and 501b that can individually control the drying conditions are continuously connected. More specifically, the area between the inlet 506 of the belt-like support 3a having the coating film of the drying box 501a and the outlet 507 of the drying box 501b is referred to as a drying zone. The number of drying boxes is not particularly limited, and can be appropriately selected depending on the coating thickness, transport speed, drying temperature, drying air volume, and the like of the belt-like support 3a having a coating to be dried. This figure shows the case where there are two drying boxes.

502a、502bは塗膜を有する帯状支持体3aに温風を供給する温風供給手段である温風供給ヘッダを示す。温風供給ヘッダ502aには、帯状支持体3aの塗膜面に対して対向して設けられた乾燥風の吹出し口502a1と、乾燥風の供給口503aとを有する箱形形状を有している。502a2は吹出し口502a1に設けたスリットノズルを示す。乾燥風供給ヘッダ502bは温風供給ヘッダ502aと同じ構造を有している。   Reference numerals 502a and 502b denote hot air supply headers which are hot air supply means for supplying hot air to the belt-like support 3a having a coating film. The hot air supply header 502a has a box shape having a dry air outlet 502a1 and a dry air supply port 503a provided facing the coating surface of the belt-like support 3a. . Reference numeral 502a2 denotes a slit nozzle provided at the outlet 502a1. The dry air supply header 502b has the same structure as the hot air supply header 502a.

幅方向に略均一な温風を吹き出すために、吹出し口に取り付けられたスリットノズルの代わりに、パンチ板、メッシュ等を使用してもかまわない。スリットノズル502a2から塗膜面に供給される乾燥風は、常温から120度程度に加熱された乾燥風を塗膜の種類に応じて適宜選択して使用することが可能となっている。504aは乾燥ボックス501aの底面に設けられた排出口を示し、504bは乾燥ボックス501bの底面に設けられた排出口を示す。   In order to blow out the substantially uniform warm air in the width direction, a punch plate, a mesh, or the like may be used instead of the slit nozzle attached to the outlet. As the drying air supplied to the coating film surface from the slit nozzle 502a2, it is possible to select and use the drying air heated from room temperature to about 120 degrees depending on the type of the coating film. Reference numeral 504a denotes a discharge port provided on the bottom surface of the drying box 501a, and reference numeral 504b denotes a discharge port provided on the bottom surface of the drying box 501b.

次に図1の(b)を使って乾燥風の流れについて説明する。尚、図中の矢印は乾燥風の流れの方向を示す。取り入れ口503aより温風供給ヘッダ502aに入った乾燥風は吹出し口502a1のスリットノズル502a2より、塗膜面に向かって吹き出し塗膜面に達する。塗膜面に向かって吹き出す乾燥風の角度は、塗膜の種類、乾燥風の温度、乾燥風の速さ等により適宜選択することが可能となっている。本図の場合は、塗膜面に向かって乾燥風を垂直に吹き出している場合を示している。   Next, the flow of the drying air will be described with reference to FIG. In addition, the arrow in a figure shows the direction of the flow of dry air. The dry air entering the warm air supply header 502a from the intake port 503a is blown out from the slit nozzle 502a2 of the blowout port 502a1 toward the coating film surface and reaches the coating film surface. The angle of the drying air blown toward the coating surface can be appropriately selected depending on the type of coating film, the temperature of the drying air, the speed of the drying air, and the like. In the case of this figure, the case where the drying wind is blown out vertically toward the coating-film surface is shown.

塗膜面に向かって吹き出された乾燥風は、この後、乾燥風は塗膜面中央部では帯状支持体3aの進行方向、または反進行方向への流れとなり、塗膜から離れた位置で幅手に移動するが、帯状支持体3aの両端部3a1、3a2の流れは両端部3a1、3a2の塗膜近傍では外へ向かって幅手方向の流れとなり帯状支持体3aの両端部3a1、3a2を回り込み排出口504aから排出される。   After that, the drying air blown toward the coating film surface flows in the direction of travel of the belt-like support 3a or the direction of counter-motion at the center of the coating film surface, and the width at a position away from the coating film. Although it moves to the hand, the flow of both ends 3a1, 3a2 of the belt-like support 3a becomes a flow in the width direction toward the outside in the vicinity of the coating film of both ends 3a1, 3a2, and the both ends 3a1, 3a2 of the belt-like support 3a It is discharged from the wrapping discharge port 504a.

塗膜を有する帯状支持体3aが乾燥ボックス501aに入った直後は、塗膜は多量の溶媒を含んでいるため動き易くなっている。乾燥ボックス501aに入った後、搬送するに従って塗膜中の溶媒が塗膜中から除去されることで塗膜は動き難くなり、乾燥ボックス501bの出口507からでる時は固定された状態になっている。   Immediately after the belt-like support 3a having the coating film enters the drying box 501a, the coating film contains a large amount of solvent, so that it is easy to move. After entering the drying box 501a, the solvent in the coating film is removed from the coating film as it is transported, so that the coating film becomes difficult to move, and when it comes out from the outlet 507 of the drying box 501b, it becomes fixed. Yes.

塗膜が多量の溶媒を含んで動き易くなっている間に、塗膜が塗膜面に向かって吹き出された乾燥風の塗膜面の速さに対して耐えられない場合は、塗膜が動き平面性が維持出来ない状態で次第に塗膜が動かなくなり、塗膜面の平面性が維持されていない状態で乾燥が終了するため、所謂吹かれムラが発生した状態となる。即ち、塗膜が塗膜面に向かって吹き出された乾燥風に対して、如何に動き難い塗膜を正常な塗布が出来る範囲で形成するか、且つ形成された塗膜面の状態に応じて、塗膜面上の乾燥風の速さを規定することで吹かれムラの発生を抑えることが可能となる。   If the coating film cannot easily withstand the speed of the coating surface of the dry air blown toward the coating surface while it contains a large amount of solvent and is easy to move, Since the coating film gradually stops moving in a state where the movement flatness cannot be maintained, and drying is completed in a state where the flatness of the coating film surface is not maintained, so-called blown unevenness occurs. That is, depending on the state of the formed coating film surface, how to form a coating film that is difficult to move with respect to the dry wind blown toward the coating film surface, and in a range where normal coating can be performed By defining the speed of the drying air on the surface of the coating film, it is possible to suppress the occurrence of blown unevenness.

本発明では、支持体上に形成された塗膜に乾燥風を吹き付け、乾燥を行う時、塗膜の物理化学特性と、塗膜の厚さと、塗膜面上の乾燥風の速さと、塗膜が乾燥するのに要する時間を式1)に示す関係にすることで吹かれムラの発生を抑えることが可能となる。   In the present invention, when drying air is blown onto the coating film formed on the support and drying is performed, the physicochemical properties of the coating film, the thickness of the coating film, the speed of the drying air on the coating film surface, By setting the time required for the film to dry to the relationship shown in Expression 1), it is possible to suppress the occurrence of blown unevenness.

式1)
0<k∫(v×h×ρ/μ)dt/t≦0.05
式中 v:塗膜上の温風の風速[m/s]
h:塗膜の厚さ[m]
ρ:塗膜の密度[kg/m3
μ:塗膜の粘度[Pa・s]
t:塗膜の乾燥に要する時間[s]
k:塗膜の種類により決まる定数
式1)において、k∫(v×h×ρ/μ)dt/t=0は物理的に存在しない数値であり、0.05<k∫(v×h×ρ/μ)dt/tであれば、塗膜強度と乾燥風の強さとのバランスがくずれ、塗膜表面に吹かれムラが発生してしまうため好ましくない。
Formula 1)
0 <k∫ (v × h × ρ / μ) dt / t ≦ 0.05
In the formula, v: the speed of warm air on the coating film [m / s]
h: thickness of coating film [m]
ρ: Density of coating film [kg / m 3 ]
μ: Viscosity of coating film [Pa · s]
t: Time required for drying the coating film [s]
k: a constant determined by the type of coating film In Equation (1), k∫ (v × h × ρ / μ) dt / t = 0 is a numerical value that does not physically exist, and 0.05 <k∫ (v × h) Xρ / μ) dt / t is not preferable because the balance between the strength of the coating film and the strength of the drying air is lost, and the coating film surface is blown and unevenness occurs.

尚、式1)において、塗膜上の温風の風速v、塗膜の厚さh、塗膜の密度ρ、塗膜の粘度μ及び塗膜の乾燥に要する時間tは、以下に示す方法により求めた値を使用した。   In Equation 1), the velocity v of warm air on the coating film, the thickness h of the coating film, the density ρ of the coating film, the viscosity μ of the coating film, and the time t required to dry the coating film are the following methods: The value obtained from the above was used.

塗膜上の温風の風速vは、日本カノマックス株式会社製風速計を用いて塗布前に支持体上から10mmの高さ位置の風速を測定した値を示す。   The wind velocity v of the warm air on the coating film indicates a value obtained by measuring the wind velocity at a height of 10 mm from the top of the support before coating using an anemometer manufactured by Nippon Kanomax Co., Ltd.

塗膜の厚さhは以下の方法により求めた値を示す。塗膜の厚さhは、時間により変化していく関数であるため、時間に対する関数の変化量を以下に示す手順で求める。   The thickness h of the coating film indicates a value obtained by the following method. Since the thickness h of the coating film is a function that changes with time, the amount of change of the function with respect to time is obtained by the following procedure.

1)乾燥ゾーンの10箇所において、乾燥ボックス内で塗膜が形成された支持体を100mm×100mm角をサンプリングする。   1) Sampling 100 mm × 100 mm square of the support on which the coating film is formed in the drying box at 10 locations in the drying zone.

2)サンプリングした試料は,すぐに密閉容器に入れ、その容器ごと質量を測定する。   2) Immediately place the sampled sample in a sealed container and measure the mass of the sample.

3)その質量からあらかじめ測定しておいた容器のみの質量を差し引き支持体と塗膜の質量を求める。   3) The mass of only the container measured in advance is subtracted from the mass to obtain the mass of the support and the coating film.

4)密閉容器中の試料を取り出し、塗膜をきれいに剥がして支持体のみの質量を測定し、3)で求めた値から支持体のみの質量を差し引き塗膜のみの質量を求める。   4) Take out the sample in the sealed container, peel off the coating film, measure the mass of the support only, and subtract the mass of the support only from the value determined in 3) to determine the mass of the coating film only.

5)求めた塗膜質量から、それぞれの位置における塗膜の厚さを式2)により算出し求める。   5) From the obtained coating film mass, the thickness of the coating film at each position is calculated by Formula 2).

塗膜の厚さ=((付き量−時間無限大における付き量)/溶媒比重)+(時間無限大における付き量/固形分比重) 式2)
塗膜の乾燥に要する時間tは、塗膜質量が一定となった時の乾燥ゾーンの入り口からの距離を、形成された塗膜を有する支持体の搬送速度で徐した式3)により算出し求める。
Film thickness = ((attachment amount−attachment amount at time infinity) / solvent specific gravity) + (attachment amount at time infinity / solid content specific gravity) Equation 2)
The time t required for drying the coating film is calculated by the equation 3) in which the distance from the entrance of the drying zone when the coating film mass becomes constant is slowed by the transport speed of the support having the formed coating film. Ask.

塗膜の乾燥に要する時間=乾燥に要した距離/支持体搬送速度 式3)
塗膜の粘度μは、時間により変化していく関数であるため、時間に対する関数の変化量を以下に示す手順で求める。
Time required for drying of coating film = distance required for drying / support conveying speed Equation 3)
Since the viscosity μ of the coating film is a function that changes with time, the amount of change of the function with respect to time is obtained by the following procedure.

1)模擬的に固形分濃度を変化させた液を作製し、各固形分濃度と粘度との関係を測定する。粘度は、B型粘度計を用いて測定した値を示す
2)塗膜の固形分濃度を付量測定により式4)より算出し求める。
1) A liquid in which the solid content concentration is simulated is prepared, and the relationship between each solid content concentration and the viscosity is measured. The viscosity indicates a value measured using a B-type viscometer. 2) The solid content concentration of the coating film is calculated from the formula 4) by weight measurement.

固形分濃度=(塗布直後の付き量×塗布直後の固形分濃度)/付き量 式4)
式中、付き量とは単位面積当たりの塗膜質量を表す。塗布直後の固形分濃度は塗膜を形成する塗布液の固形分濃度を示し、塗布液の処方より計算で求める。
Solid content concentration = (attachment amount immediately after application × solid content concentration immediately after application) / attachment amount Formula 4)
In the formula, the attached amount represents the coating film mass per unit area. The solid content concentration immediately after coating indicates the solid content concentration of the coating solution for forming the coating film, and is calculated from the formulation of the coating solution.

3)1)で求めた各固形分濃度と粘度との関係より、2)で求めた塗膜の固形分濃度に対する粘度を求め、これを塗膜粘度とする。   3) From the relationship between the solid content concentration and the viscosity obtained in 1), the viscosity of the coating film obtained in 2) with respect to the solid content concentration is obtained, and this is defined as the coating film viscosity.

塗膜の密度ρは、時間により変化していく関数であるため、時間に対する関数の変化量を以下に示す手順で求める。   Since the density ρ of the coating film is a function that changes with time, the amount of change of the function with respect to time is obtained by the following procedure.

1)塗膜の厚さhを求める手順に従って求める。   1) Obtain according to the procedure for obtaining the thickness h of the coating film.

2)付き量を求め、式5)により計算で求める。   2) Obtain the attached amount and obtain it by calculation according to Equation 5).

塗膜の密度=付き量/塗膜の厚さ 式5)
尚、塗膜面上の風速vは、日本カノマックス株式会社製風速計を用いて塗布前に支持体上から10mmの高さ位置の風速を測定した値を示す。
Density of coating film = attachment amount / thickness of coating film Formula 5)
In addition, the wind speed v on a coating-film surface shows the value which measured the wind speed of the 10-mm height position from the support body before application | coating using the Nippon Kanomax Corporation anemometer.

本発明に係る塗布液は、特に限定されず、例えば写真感光材料、熱現像感光材料、アブレーション記録材料、印刷製版材料、磁気記録材料、感圧及び感熱記録材料、易接着性、易滑性、ガス遮断性、防湿性、制電性、インク受容性等の機能を付与する材料に使用する塗布液が挙げられる。また、塗布液中の溶媒についても特に限定されず、水、有機溶剤を溶媒とする系に適用できる。それら塗布液を塗布する方式も「MODERN COATING AND DRYING TECHNOLOGY」に各種記載されているが、本発明に係る適用には特に限定されない。   The coating solution according to the present invention is not particularly limited, and for example, a photographic material, a photothermographic material, an ablation recording material, a printing plate making material, a magnetic recording material, a pressure-sensitive and heat-sensitive recording material, easy adhesion, easy slipping, Examples thereof include coating liquids used for materials that provide functions such as gas barrier properties, moisture proof properties, antistatic properties, and ink acceptability. Further, the solvent in the coating solution is not particularly limited and can be applied to a system using water or an organic solvent as a solvent. Various methods for applying these coating solutions are also described in "MODER COATING AND DRYING TECHNOLOGY", but are not particularly limited to the application according to the present invention.

また、本発明に適用される支持体も特に限定されず、紙、プラスチック、金属などの支持体に適用できる。代表的支持体の材質としては、プラスチックではポリエチレンテレフタレート(PET)、金属ではアルミニウム等が挙げられる。   Moreover, the support body applied to this invention is not specifically limited, It can apply to support bodies, such as paper, a plastics, and a metal. Typical materials for the support include polyethylene terephthalate (PET) for plastics and aluminum for metals.

以下に本発明の実施例を挙げて具体的に説明するが、本発明の実施態様はこれらの例に限定されるものではない。   Examples of the present invention will be specifically described below, but the embodiments of the present invention are not limited to these examples.

実施例1
(塗布液の調製)
ポリビニルブチラール樹脂(積水化学工業(株)製:エスレック BL−1)を粘度1500mPa・sとなるようにメチルエチルケトンに溶解して塗布液とした。塗布液の粘度の測定はB型粘度計を使用し、温度20℃で測定した値である。
Example 1
(Preparation of coating solution)
A polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd .: ESREC BL-1) was dissolved in methyl ethyl ketone so as to have a viscosity of 1500 mPa · s to obtain a coating solution. The viscosity of the coating solution is a value measured at a temperature of 20 ° C. using a B-type viscometer.

(塗布・乾燥)
上記塗布液を図1に示す乾燥装置(但し、乾燥ボックスは長さ20mを1つ)を使用し、エクストルージョンコーターを用いて、連続して搬送される厚さ180μm、幅1000mmの帯状支持体(PETを使用)上へ、表1に示す様に前記式1)に用いる塗膜の密度ρと、粘度μと、膜厚hと、塗膜上の温風の風速vと、塗膜の乾燥に要する時間tとの関係を変化させ、塗布幅900mm、塗布長300mとなるように塗布速度30m/分で塗布・乾燥を行い試料を作製し101〜110とした。但し、kは1.1とした。乾燥温度は50℃とした。
(Coating / Drying)
A belt-like support having a thickness of 180 μm and a width of 1000 mm is transported continuously using the drying apparatus shown in FIG. 1 (however, the drying box has a length of 20 m) and an extrusion coater. (Using PET) Above, as shown in Table 1, the density ρ, the viscosity μ, the film thickness h of the coating film used in the above formula 1), the wind velocity v of the hot air on the coating film, and the coating film The relationship between the time t required for drying was changed, and coating and drying were performed at a coating speed of 30 m / min so as to obtain a coating width of 900 mm and a coating length of 300 m. However, k was 1.1. The drying temperature was 50 ° C.

Figure 2005249287
Figure 2005249287

塗膜上の温風の風速vは、日本カノマックス株式会社製風速計を用いて塗布前に支持体上から10mmの高さ位置の風速を測定した結果である。前記式1)の計算を行うにあたって、式中塗膜の厚さh、塗膜の密度ρ、塗膜の粘度μは時々変化していく関数であるため、時間に対する各関数の変化量を把握する必要があるため以下の方法により求めた。   The wind velocity v of the warm air on the coating film is the result of measuring the wind velocity at a height of 10 mm from the top of the support before coating using an anemometer made by Nippon Kanomax Co., Ltd. In calculating the equation (1), the thickness h of the coating film, the density ρ of the coating film, and the viscosity μ of the coating film are functions that change from time to time. Therefore, the following method was used.

表1に示すそれぞれの条件において、塗布を行っている途中で搬送を止め、支持体上の塗膜情報を得るため、搬送方向10箇所において乾燥ボックス内にある塗膜を有する帯状支持体を100mm角でサンプリングした。サンプリングした試料はすぐに密閉容器に入れ、その容器ごと質量を測定した。その質量からあらかじめ測定しておいた容器のみの質量を除いたものが支持体と塗膜の質量であり、そのサンプルの塗膜をきれいに剥がして支持体のみの質量を測定し、除することにより塗膜のみの質量を求めた。
求めた塗膜の質量から、それぞれの位置における塗膜の厚さhを前記2)式により算出し、搬送方向での塗膜質量の変化から塗膜の乾燥に要する時間tを前記3)式により算出した。以下付量とは単位面積当たりの塗膜質量を表すものとする。
In each condition shown in Table 1, in order to stop the conveyance in the middle of coating and obtain the coating film information on the support, the belt-shaped support having the coating film in the drying box at 10 locations in the conveyance direction is 100 mm. Sampled at the corner. The sampled sample was immediately put in a sealed container, and the mass of the container was measured. The mass of the support and the coating film, excluding the mass of the container that has been measured in advance from the mass, is the mass of the support and the coating film. The mass of only the coating film was determined.
From the obtained coating film mass, the thickness h of the coating film at each position is calculated by the above equation 2), and the time t required for drying the coating film from the change in coating film mass in the transport direction is calculated by the above equation 3). Calculated by Hereinafter, the applied amount represents the mass of the coating film per unit area.

塗膜の粘度μは、模擬的に固形分濃度を変化させた液を作製し、その粘度を測定することで固形分濃度と粘度の関係を求めた。なお塗膜の固形分濃度に関しては、付量測定により前記4)式を用いて算出した。さらに塗膜密度ρを前記5)式により求めた。   The viscosity μ of the coating film was obtained by preparing a liquid in which the solid content concentration was simulated and measuring the viscosity to obtain the relationship between the solid content concentration and the viscosity. The solid content concentration of the coating film was calculated using the above formula 4) by weight measurement. Furthermore, the coating film density ρ was determined by the above formula 5).

以上の方法で求めた、乾燥条件を塗膜の密度ρと、粘度μと、膜厚hと、塗膜上の温風の風速vと、塗膜の乾燥に要する時間tを用いて前記1)式による計算を行った。   The drying conditions determined by the above method are the above-described 1 using the coating film density ρ, viscosity μ, film thickness h, warm air velocity v on the coating film, and time t required for drying the coating film. ) Calculation was performed.

(評価)
作製した各試料101〜110について、塗布終了後100m毎に1mをサンプリングし、目視による吹かれムラを観察し、以下の評価ランクに従って評価した結果を表2に示す。
(Evaluation)
With respect to each of the produced samples 101 to 110, 1 m was sampled every 100 m after the application was completed, and blown unevenness was visually observed. Table 2 shows the results of evaluation according to the following evaluation ranks.

吹かれムラの評価ランク
◎:吹かれムラがほとんどない
○:極わずかの吹かれムラが認められる
△:実用上問題とならない程度の吹かれムラがある
×:実用化が困難な吹かれムラがある
Evaluation rank of blown unevenness ◎: There is almost no blown unevenness ○: Very slight blown unevenness is recognized △: There is blown unevenness that is not a problem in practical use ×: Blown unevenness that is difficult to put into practical use is there

Figure 2005249287
Figure 2005249287

本発明の有効性が確認された。 The effectiveness of the present invention was confirmed.

実施例2
(塗布液の調製)
実施例1と同じ塗布液を使用した。
Example 2
(Preparation of coating solution)
The same coating solution as in Example 1 was used.

(塗布・乾燥)
上記塗布液を図1に示す2つの乾燥ボックスを有する乾燥装置(但し、1つの乾燥ボックスは長さ10m)を使用し、エクストルージョンコーターを用いて、連続して搬送される厚さ180μm、幅1000mmの帯状支持体(PETを使用)上へ、表3に示す様に前記式1)に用いる塗膜の密度ρと、粘度μと、膜厚hと、塗膜上の温風の風速vと、塗膜の乾燥に要する時間tとの関係を変化させ、塗布幅900mm、塗布長300mとなるように塗布速度30m/分で塗布・乾燥を行い試料を作製し201〜210とした。但し、kは1.1とした。乾燥温度は入り口側の乾燥ボックスを50℃とし、出口側を70℃とした。
(Coating / Drying)
Using the drying apparatus having the two drying boxes shown in FIG. 1 (with one drying box having a length of 10 m), the coating liquid is continuously transported using an extrusion coater with a thickness of 180 μm and a width. On a 1000 mm belt-like support (using PET), as shown in Table 3, the density ρ, the viscosity μ, the film thickness h of the coating film used in the above formula 1), and the wind velocity v of the hot air on the coating film The sample was prepared as 201 to 210 by changing the relationship with the time t required for drying the coating film and applying and drying at a coating speed of 30 m / min so that the coating width was 900 mm and the coating length was 300 m. However, k was 1.1. The drying temperature was 50 ° C for the drying box on the inlet side and 70 ° C for the outlet side.

Figure 2005249287
Figure 2005249287

塗膜上の温風の風速vは、実施例1と同じ方法で測定した結果である。前記式1)の計算を行うにあたって、式中塗膜の厚さh、塗膜の密度ρ、塗膜の粘度μは表3に示すそれぞれの条件において、実施例1と同じ方法で求めた値である。   The wind velocity v of the warm air on the coating film is the result measured by the same method as in Example 1. In the calculation of Formula 1), the thickness h of the coating film, the density ρ of the coating film, and the viscosity μ of the coating film are values obtained by the same method as in Example 1 under the respective conditions shown in Table 3. It is.

(評価)
作製した各試料201〜210について、塗布終了後100m毎に1mをサンプリングし、目視による吹かれムラを観察し、実施例1と同じ評価ランクに従って評価した結果を表4に示す。
(Evaluation)
For each of the produced samples 201 to 210, 1 m is sampled every 100 m after the application is finished, the blown unevenness is visually observed, and the results of evaluation according to the same evaluation rank as in Example 1 are shown in Table 4.

Figure 2005249287
Figure 2005249287

本発明の有効性が確認された。   The effectiveness of the present invention was confirmed.

従来の温風吹き出し方式の乾燥ボックスを持つ乾燥装置を用いた乾燥方法の一例を示す概略図である。It is the schematic which shows an example of the drying method using the drying apparatus with the drying box of the conventional warm air blowing method.

符号の説明Explanation of symbols

1 コーター
3 帯状支持体
3a 塗膜を有する帯状支持体
5 乾燥装置
501a、501b 乾燥ボックス
502a、502b 温風供給ヘッダ
DESCRIPTION OF SYMBOLS 1 Coater 3 Strip | belt-shaped support body 3a Strip | belt-shaped support body which has a coating film 5 Drying apparatus 501a, 501b Drying box 502a, 502b Hot air supply header

Claims (1)

連続的に搬送する帯状支持体上に塗布液を塗布して塗膜を形成した後、該塗膜を有する帯状支持体を搬送しながら乾燥ゾーンで温風を吹き付けることにより前記塗膜を乾燥する乾燥方法において、
前記塗膜の密度と、粘度と、厚さと、
前記塗膜上の該温風の風速と、
前記塗膜の乾燥に要する時間との関係が式1)を満たす条件で、前記塗膜を乾燥することを特徴とする乾燥方法。
式1)
0<k∫(v×h×ρ/μ)dt/t≦0.05
式中 v:塗膜上の温風の風速[m/s]
h:塗膜の厚さ[m]
ρ:塗膜の密度[kg/m3
μ:塗膜の粘度[Pa・s]
t:塗膜の乾燥に要する時間[s]
k:塗膜の種類により決まる定数
After coating the coating solution on the belt-like support that is continuously conveyed to form a coating film, the coating film is dried by blowing warm air in the drying zone while conveying the belt-like support having the coating film. In the drying method,
The density, viscosity, thickness of the coating film,
Wind speed of the warm air on the coating film;
A drying method characterized in that the coating film is dried under the condition that the relationship with the time required for drying the coating film satisfies the formula 1).
Formula 1)
0 <k∫ (v × h × ρ / μ) dt / t ≦ 0.05
In the formula, v: the speed of warm air on the coating film [m / s]
h: thickness of coating film [m]
ρ: Density of coating film [kg / m 3 ]
μ: Viscosity of coating film [Pa · s]
t: Time required for drying the coating film [s]
k: Constant determined by the type of coating film
JP2004060227A 2004-03-04 2004-03-04 Drying method Pending JP2005249287A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108507278A (en) * 2018-03-29 2018-09-07 宁波希奇服饰有限公司 One kind, which is dyed cloth, expects drying wrap-up
WO2022133724A1 (en) * 2020-12-22 2022-06-30 苏州莫愁文化科技有限公司 Silk drying apparatus

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108507278A (en) * 2018-03-29 2018-09-07 宁波希奇服饰有限公司 One kind, which is dyed cloth, expects drying wrap-up
WO2022133724A1 (en) * 2020-12-22 2022-06-30 苏州莫愁文化科技有限公司 Silk drying apparatus

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