JPH03235221A - Method and device for drying long-sized film - Google Patents

Abstract

PURPOSE:To provide the method and device which stabilizes the traveling of a long-sized film and uniformly dries the coated film thereof by ejecting hot wind radially from the center of a curvilinear orbit to the curvilinear traveling part of the long-sized film and blowing the hot wind to the long-sized film from the outer side of the curvilinear orbit as well. CONSTITUTION:A 1st hot wind nozzle body 7 which blows out the hot wind radially to the curvilinear traveling part of the long-sized film 4 is disposed alongside the virtual line connecting a pair of guide rollers 6 and, therefore, the long-sized film 4 receives the uniform hot wind in the curvilinear traveling part a thereof. A 2nd hot wind nozzle body 11 is provided apart a spacing from the 1st hot wind nozzle body 7 so as to blow out the hot wind toward the 1st hot wind nozzle body 7 from the circumference thereof and, therefore, the long-sized film 4 travels curvilinearly in nearly the arc-shaped orbit where the wind pressures o the hot wind blown out of the 1st and 2nd hot wind nozzle bodies 7, 11 balance each other. The smooth traveling is assured in this way and the local drying of the coating compd. on the film surface is prevented. The coated film is thus uniformly cured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for drying a long film,
In particular, the present invention relates to a drying method and apparatus suitable for the drying process of magnetic paint when producing magnetic tape.

[Prior art] Magnetic tapes such as video tapes and audio tapes are made by applying magnetic paint to the surface of a thin base film such as a polyester film, drying it, and going through a process that includes smoothing the surface. It is manufactured by making a long magnetic tape material and cutting it into a predetermined width.

In the manufacturing process of the original magnetic tape, the above-mentioned steps are performed continuously while a long film is wound from one roll to the other roll.

In this manufacturing process, various drying methods are used to dry the magnetic paint applied to the surface of the base film, but the main method is to blow warm air onto the surface of the moving base film. , hot air drying is used to dry the paint on the surface.

In the manufacturing process of such magnetic tapes, it is required to increase the running speed of the base film in order to improve productivity. However, as the film travels at higher speeds, the time it is exposed to warm air during the drying process becomes shorter, and there is no longer enough time to dry the paint applied to the base film. In other words, in order to expose the paint to warm air for a sufficient period of time to dry it, the faster the film travels, the longer it must travel, which necessitates larger equipment. .

Therefore, as a countermeasure against this problem, a drying device as shown in FIG. 4 has been adopted. In this drying device, one roll 1
A paint is applied to the surface of the long film 4 fed out from the coating unit 2, and the long film 4 is passed through the guide roller 3.8 and the surface treatment roller 9 and wound onto the other roll 10. Pass through drying room 5.5...

In this drying chamber 5.5..., between a pair of guide rollers 6.6 that guide the long film 4, a nozzle 7 is moved in a direction perpendicular to an imaginary line connecting the guide rollers 6.6.
Hot air is blown onto the long film 4 from ', and the long film 7 is caused to run in an Ω-shape to the side of the imaginary line connecting the guide rollers 6.6 by the wind pressure of the hot air.

In this method, since the long film 4 travels in a curved manner, the travel distance of the long film 4 can be increased accordingly, and the long film 4 can be exposed to hot air for a correspondingly longer time.

Problems to be Solved by the Invention] In the conventional device, hot air is blown onto the long film 4 from the nozzle 7' in a direction perpendicular to the imaginary line connecting the guide rollers 6.6. The wind pressure that the long film 4 receives from the warm air is particularly high at the center of the guide roller 6.
does not curve properly in an Ω-shape, but actually curves while drawing an approximate elliptical arc trajectory, as shown in FIG.

However, when a long film runs in a curved manner on such a track, the running becomes unstable and the running track becomes unstable.
Running may be disrupted.

Moreover, because the hot air blows strongly locally, rapid drying occurs in some areas, causing only the surface layer of the resin contained in the paint to condense, leaving the paint film uneven without being completely dry inside. Problems such as the occurrence of problems are likely to occur.

Furthermore, since the hot air hits only one side of the long film 4, mainly the surface coated with paint, only the surface layer of the paint film is cured first, and the internal hardening progresses with a delay, so that the surface layer of the paint film and Distortion such as shrinkage of the coating film may occur due to the difference in the progress of curing with the inside, which may cause a decrease in the quality of the coating film.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a drying method and apparatus capable of solving the above-mentioned conventional problems and capable of stabilizing the running of a long film and uniformly drying a coating film.

[Means for Solving the Problems] That is, in order to solve the above-mentioned problems, in the present invention, the long film 4 is caused to travel, and a long film is moved between a pair of guide rollers 6.6 for guiding the long film 4. shaku film 4
In the long film drying method, the long film 4 is curved to the side of the imaginary line connecting the guide rollers 6.6 by blowing hot air to the wind pressure of the hot air. To provide a method for drying a long film, in which warm air is jetted radially from the center of the curved trajectory, and hot air is blown onto the long film from the outside of the curved trajectory.

Further, the long film drying device includes a pair of idle rollers 6.6 for guiding the traveling long film 4, and means for blowing hot air onto the surface of the long film 4 traveling between the guide rollers 6.6. , the guide roller 6
．． The means for blowing hot air onto the long film 4 traveling between the first hot air nozzle body 7 that blows hot air radially
and a second hot air nozzle body 11, the first hot air nozzle body 7 is arranged on the side of the imaginary line connecting the pair of idle rollers 6.6, and the second hot air nozzle body 11 is , a long film dryer disposed facing the first hot air nozzle body 7 at a distance so as to surround the first hot air nozzle body 7 so as to blow hot air from around the first hot air nozzle body 7. Provide equipment.

[Function] In the drying method according to the present invention, the long film 4 blows hot air radially from the center of the curved trajectory at the curved running portion a of the long film 4.
receives even pressure of warm air. In addition, in order to receive uniform wind pressure, the long film 4 draws an arcuate trajectory at the point where its tension and the wind pressure of the warm air blown out from the first and second hot air nozzle bodies are balanced. Runs in a curved direction. This allows the long film 4 to run smoothly and prevents the paint from drying locally on its surface.

In addition, since hot air is applied not only from the inside of the curved running portion a of the long film 4 but also from the outside thereof, heating and drying are performed from both the surface layer of the coating film of the long film 4 and the long film 4 side. progresses.

Therefore, it is avoided that only the surface layer of the coating film is cured and the internal curing is delayed, and the coating film is uniformly cured.

Furthermore, in the drying device according to the present invention, since the first hot air nozzle body 7 that blows hot air radially is arranged on the side of the imaginary line connecting the pair of guide rollers 6.6,
In the curved traveling portion a of the long film 4, warm air can be blown out radially from the center of the curved trajectory. Also,
The second hot air nozzle body 11 is arranged to face the first hot air nozzle body 7 at a distance so as to blow hot air from the periphery toward the first hot air nozzle body 7. Therefore, warm air can be applied from around the curved trajectory at the curved traveling portion a of the long film 4. This allows the method to be carried out easily.

[Example] Examples of the present invention will be described in detail below.

FIG. 1 shows a magnetic tape manufacturing apparatus equipped with a drying device according to an embodiment of the present invention. First, a long film 4, which serves as the base of the magnetic tape, is pulled out from the roll 1, and a magnetic paint is applied to its surface in the coating section 2. Thereafter, the drying device is placed between the guide rollers 3 and 8.

This drying device consists of five drying chambers 5.5... arranged in series, and each of the drying chambers 5.5... has a pair of guide rollers 6.6 and a first roller. Each is provided with a second hot air nozzle body 7.11.

As shown in FIGS. 2 and 3, the first hot air nozzle body 7 is provided with a large number of hot air blowing holes uniformly distributed on the circumferential surface 7a of a cylindrical main body. 7 b.

The hot air supplied from 7b is uniformly blown out from this hot air outlet. Therefore, hot air is uniformly radially blown out from this hot air nozzle body 7. This hot air nozzle body 7 is arranged away from the center of an imaginary line connecting the pair of guide rollers 6.6 in a direction perpendicular to the imaginary line, and the duct 7b is located there.

7b is rotated around the central axis. Due to this rotation, the hot air radially blown out from the hot air nozzle body 7 is released in a spiral shape, as shown by the arrow in FIG. 2, and becomes a spiral.

This first hot air nozzle body 7 may be one that blows out hot air radially and uniformly, in addition to the one described above, one that has a cylindrical surface with slits, or one that is a cylindrical body formed of a porous material. etc. may be used. Furthermore, instead of having a cylindrical shape, it may be an assembly of nozzles, for example, in which a plurality of fine nozzles with their tips oriented radially are arranged vertically.

As shown in FIG. 2, the second hot air nozzle body II is connected to the same hot air nozzle body within a range of about 100° with an interval such that the hot air blowing surface 12 becomes the hot air nozzle body 7. It is arranged so as to surround the warm air blowing surface of No. 7, that is, its circumferential surface. Behind the hot air blowing surface of the hot air nozzle body 11, a screen 13 is disposed to uniformly disperse the hot air introduced from the digestion introduction duct 14 side. The wind is starting to blow.

The hot air blowing surface 12 of this second hot air nozzle body 11 is generally a concave cylindrical surface with a large number of fine warm air blowing holes, but it is also a hot air blowing surface 12 having a vertically thin wet blowing slit. Alternatively, it may be a perforated plate. Furthermore, instead of the box-shaped hot air nozzle body as shown in the figure, a collection of multiple nozzles arranged vertically with the tips of a large number of fine nozzles directed centripetally toward the first hot air nozzle body 7. It may be the body.

The long film 4 guided by the pair of guide rollers 6.6 travels along a curved trajectory between the first hot air nozzle body 7 and the second hot air nozzle body II. During this period, hot air is blown out uniformly from the first and second hot air nozzle bodies 7, 11, so that the curved trajectory of the long film 4 is such that the curved trajectory of the long film 4 is blown out from the first hot air nozzle body 7. Where the wind pressure of the warm air, the tension of the long film 4 opposing the wind pressure, and the wind pressure of the warm air jetted from the second hot air nozzle body 11 are balanced, a circular arc trajectory is formed. Therefore, the center of the first hot air nozzle body 7 is arranged at the center of this planned arcuate trajectory, and the long film is In relation to the tension applied to 4, determine the flow rate and wind speed of the warm air injected from the first and second hot air nozzle bodies 7 and 11, respectively, and the rotation speed of the first hot air nozzle body 7,
Control. Naturally, the wind pressure applied to the long film 4 from the inside of its curved trajectory by the hot air blown out from the first hot air nozzle body 7 is the same as the wind pressure applied from the outside by the hot air from the second hot air nozzle body 11. We have to make it stronger.

In this way, the long film 4 is dried in the drying chamber 5.5...
By being exposed to hot air, the magnetic paint applied to the surface of the film 4 dries.

Subsequently, the long film 4 that has passed through the drying chambers 5, 5, . Thereafter, this is heat-treated for a while to polymerize the resin component of the magnetic paint, thereby completing the original magnetic tape.

[Effects of the Invention] As explained above, according to the present invention, when hot air is applied to the long film 4 to dry the paint on the surface thereof, the long film 40 reliably forms an arcuate trajectory, and the arc Uniform hot air can be applied to the long film 4 from inside and outside the orbit. As a result, the running stability of the long film 4 is increased, and the drying is performed uniformly, thereby achieving the effect of improving productivity and quality.

[Brief explanation of drawings]

FIG. 1 is a plan view of a running system for a long film including a drying device according to an embodiment of the present invention, FIG. 2 is a plan view of the main parts of the same drying device, and FIG. FIG. 4 is a perspective view showing an example of a hot air nozzle body, and FIG. 4 is a plan view of a long film running system including a conventional drying device. 4... Long film 6... Guide roller 7...
・First hot air nozzle body 11... Second hot air nozzle body a... Curved running part of long film

Claims (2)

[Claims] (1) While running the long film 4, hot air is blown onto the long film 4 between a pair of guide rollers 6, 6 that guide the long film 4, and the wind pressure of the hot air is applied to the long film 4. In the long film drying method in which the long film 4 is run curved to the side of the imaginary line connecting the guide rollers 6, 6, hot air is radiated from the center of the curved trajectory at the curved run portion a of the long film 4. Also, a long film drying method characterized by blowing hot air onto the long film from outside the curved track. (2) Long film drying comprising a pair of guide rollers 6, 6 for guiding the running long film 4, and means for blowing hot air onto the surface of the long film 4 running between the guide rollers 6, 6. In the device, the guide roller 6;
A means for blowing hot air onto the long film 4 traveling between the two hot air nozzles 6 includes a first hot air nozzle body 7 and a second hot air nozzle body 11 that blow hot air radially. The nozzle body 7 is arranged on the side of the imaginary line connecting the pair of guide rollers 6, 6, and the second hot air nozzle body 11 directs hot air from its surroundings toward the first hot air nozzle body 7. As if to burst out,
A long film drying device characterized in that it is disposed opposite to the first hot air nozzle body 7 so as to surround it at a distance.