JPH0741671B2 - Method and apparatus for heat-shrinking heat-shrinkable film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a heat-shrinkable film for surface treatment such as a protective film and a display film for a trade name, etc., in close contact with a work piece which is a main body of a product. The present invention relates to a method and apparatus for heat-shrinking a heat-shrinkable film which is adhered to a substrate.

<Prior Art> Conventionally, as a method of closely attaching a heat-shrinkable film for protection, display of a product name, etc. to a work piece which is a main body of the product, a hot air method, a heat radiation method or those methods. Combined dry method, hot water shower method, hot water bath method or JP-A-61
A wet method such as a steam method described in Japanese Patent Laid-Open No. 115826 is known.

The above-mentioned dry method is simple and easy to construct, and is most practically used at present. However, this dry method uses air as a heat medium and a space as a transfer path, and thus has a low thermal conductivity. Therefore, in order to heat-shrink the heat-shrinkable film loosely fitted to the work piece and adhere it to the work piece in an intimate contact state, it is necessary to retain the heat-shrinkable film in the dry heat treatment apparatus for about 3 to 10 seconds. As a result, the workpiece is heated at the same time as the heat-shrinkable film, so that the workpiece having a low heat resistant temperature and a low thermal deformation temperature and a small heat capacity may be deformed by heat. For example, the shrink temperature of heat shrinkable film is generally 60 to 100 ℃, and the heat distortion temperature of polyvinyl chloride (PVC) or polyethylene terephthalate (PET) is 5
Since the temperature is 4 to 76 ° C, the work made of PVC or PET easily deforms when heated to a temperature at which the heat-shrinkable film shrinks, and the shrinkage of the heat-shrinkable film does not occur at the temperature that avoids the deformation of the work. Completely causes tarmi and wrinkles.
Also, at this time, if printed on the heat shrinkable film,
Since the printing causes unevenness in color and distortion, the processing work becomes more difficult and has no commercial value.

Further, in the dry method, since the heat medium is air as described above, the processing temperature of the heat treatment apparatus is likely to change due to the influence of atmospheric temperature and the flow of ambient air. For example, the processing temperature is likely to change due to changes in temperature and humidity depending on the season or day and night, or opening and closing of a factory window, and special processing technology is required, so quality control is not easy.

On the other hand, the wet method uses water or water vapor having a large specific heat as a heat medium, so the heat is almost instantly transferred to the film, and the time for allowing the work to stay in the device is about It may be as short as about 1 second. Therefore, even a work piece such as PVD or PET having a low deformation temperature as described above is less likely to be thermally deformed, and the heat shrinkable film can be adhered to the work piece in a close contact manner.

Further, in the wet method, particularly in the hot water shower type or the hot water bath type, the temperature of the hot water as the heat medium can be stably set or controlled without being affected by the environmental conditions outside the apparatus, which makes difficult processing technology difficult. Since stable quality control can be performed without requiring much, a good finish can always be expected.

Furthermore, the wet method has an effect that heat loss is small and the processing speed is fast, which is not present in the dry method.

<Problems to be Solved by the Invention> However, in the hot water shower type or the hot water bath type, it cannot be applied to a workpiece to which water must not infiltrate or adhere, and after the processing is finished, It takes a lot of energy and time to remove and dry the water adhering to the work piece.

Further, in the steam type, although the problem of water infiltration and adhesion described above is not a concern, the steam as the heat medium is 100
Since the temperature is ℃, the heat-shrinkable film applied to the work piece is bent at the end due to the too high injection temperature, and the printed part of the heat-shrinkable film is distorted, which impairs the commercial value. Easy to get rid of. This cannot be easily solved even if the conditions for temporal and radial region when the workpiece is conveyed by the conveyor and rushed into the steam mass of the heat treatment apparatus are variously changed.

Therefore, it is an object of the present invention to solve the above-mentioned drawbacks of the steam type in the steam type having the most advantages, mainly by a steam injection mechanism or method.

<Means for Solving the Problems> The present invention is to move a work piece located on the axis of a tunnel portion having a plurality of steam injection ports in the longitudinal direction, and to be covered by the steam injected from each steam injection port. In the heat-shrinking method of a heat-shrinkable film, wherein a heat-shrinkable film attached to the outer surface of a work is heated and shrunk, in the tunnel part, a plurality of steam injection ports are annularly provided at a first position close to the inlet. Are arranged at equal intervals, and a plurality of steam injection ports are annularly arranged at a second position close to the outlet, and the steam injection ports at the second position are connected to those of the first position. It is set so as to be positioned within the interval, and the heat-shrinkable film is heated in a horizontal strip shape along the moving direction of the workpiece by the steam from the steam injection port at the first position, The steam is used to heat the unheated part in a horizontal band. It is intended to provide a thermal shrinkage method and thermal shrinkage apparatus of the heat-shrinkable film characterized.

<Examples> Hereinafter, the present invention will be described based on Examples of the drawings.

The heat shrinking device 1 of the present invention shown in FIGS. 1 to 3 has a tubular tunnel portion 4 having an inlet opening end 2 and an outlet opening end 3.
And a steam injection device 5 having a closed frame shape,
It is composed of a conveyor mechanism 6 located on the axis of the steam tunnel portion 4.

A plurality of steam injection ports 7, 7'are formed in an annular shape at a first position near the inlet opening end 2 of the tunnel portion 4 of the steam injection device 5 and at a second position near the outlet opening end 3 of the tunnel portion 4. They are arranged at equal intervals.

In the embodiment shown in the drawings, at the first position near the inlet opening end 2 of the tunnel portion 4, four steam injection ports 7 ... Are arranged at equal intervals in the vertical and horizontal directions, and near the outlet opening end 3 of the tunnel portion 4. At the position, four steam injection ports 7'are arranged diagonally above and to the left and diagonally below and to the left and right at equal intervals. Therefore,
Each steam injection port 7, 7'is annularly arranged at equal intervals of 45 degrees, and each steam injection port at the first position is located within the interval between adjacent steam injection ports 7'at the second position. Are set as follows (FIGS. 2 and 3).

A float 8 and a float valve 9 are provided below the tunnel portion 4 of the steam injecting device 5 to regulate the level of water supplied from the water supply pipe 10 into the steam injecting device 5 at a constant level. A heater 11 is provided in the inside of 5 to heat water to generate steam, which can be sprayed from each steam jet port 7, 7'to the center of the tunnel portion 4.

The conveyor mechanism 6 that penetrates the tunnel portion 4 of the vapor injection device 5 penetrates the tunnel portion 4 through at least two endless flexible wires 13 held by a plurality of pulleys 12 ... , Which is driven by the motor 14 to move from the inlet opening end 2 toward the outlet opening end 3 and mounts the work piece a on the inside of the tunnel portion 4 of the steam injection device 5 from the inlet opening end 2 to the outlet opening. It can be conveyed to the end 3 and the axis of the workpiece a is located on the axis of the tunnel portion 4 during conveyance.

In addition, the above-mentioned flexible linear member 13 is tough and has heat resistance that does not hinder steam injection, that is, heat shrinkage.
Water resistant chains or flexible wires can be used.

In order to heat-treat the workpiece a by the heat shrinking device 1 of the present invention configured as described above, the water in the steam injection device 5 is heated and boiled by the heater 11 to fill the steam injection device 5 with steam. The steam is ejected from each steam injection port 7, 7 ′ toward the center of the tunnel portion 4. Then, when the workpiece a with the heat-shrinkable film loosely covered by the conveyor mechanism 6 in the tunnel portion 4 is conveyed and passed from the inlet opening end 2 toward the outlet opening end 3, the workpiece a becomes first. When passing through the steam injection port 7 at the position, the hatched portion Y in FIG.
As described above, the water vapor is jetted in the shape of a horizontal strip along the moving direction of the workpiece a, and the heat-shrinkable film in the shaded portion Y momentarily shrinks. Then, when the workpiece a passes through the steam injection port 7'in the second position, the unheated portion is left in each steam injection port 7 '.
As a result, water vapor is jetted in the shape of a horizontal strip as indicated by the shaded portion Z in FIG. 5, and the heat-shrinkable film in the shaded portion Z is momentarily heat-shrinked. Since steam is jetted, the entire surface of the heat-shrinkable film is shrunk. It should be noted that each of the steam injection ports 7 and 7 ′ has an outer surface of the workpiece a of approximately 4 mm.
By injecting water vapor within the range of 5 degrees, the shaded portion Y and the shaded portion Z do not overlap with each other and no gap can be formed. Further, the flexible linear member 13 is extremely thin,
In addition, if it is positioned between the shaded portion Y and the shaded portion Z where the steam injection is avoided, the steam injection is not affected.

Therefore, according to the heat-shrinking apparatus 1 shown in the embodiment of FIGS. 1 to 3, the workpiece a to which the heat-shrinkable film is loosely adhered is moved by the conveyor mechanism 6 from the entrance opening end 2 into the tunnel portion 4. Only by transporting it toward the outlet opening end 3, the steam jet ports 7 and 7 ′ heat it in a horizontal strip shape along the moving direction of the workpiece a, and the heat-shrinkable film is heat-shrinked to be processed a. It adheres to the outer surface of the.

6 to 8 show a second embodiment of the heat shrinking device 1 of the present invention, in which the tunnel portion 4 has a large-diameter cylindrical shape, and each steam injection port 7, 7'is a small-diameter cylindrical shape. Then, the steam injection ports 7 and 7'can be adjusted to be positioned in the tunnel portion 4 by the adjusting screw 15, and when the workpiece a has a large diameter, it is projected into the tunnel portion 4 shallowly, If the diameter is small, it will be pushed deeper.

A nozzle 18 provided at the tip of a steam supply pipe 17 connected from a steam generation mechanism 16 for generating steam at high pressure is exposed to each steam injection port 7, 7 '.

In the embodiments of FIGS. 6 to 8, the reference numerals not described have the same configurations as the same reference numerals in the above-mentioned embodiments, and therefore the description thereof will be omitted.

The heat treatment method of the heat shrinking apparatus 1 of the second embodiment of the present invention configured as described above is basically the same as that of the first embodiment described above, but the heat shrinking apparatus of the second embodiment is the same. According to this, the following effects can be expected.

In this heat shrink device, when water vapor is jetted from each nozzle 18, air is sucked from the rear side of the steam jet port 7 due to the jet flow, and this air is mixed with the water vapor jetted from the nozzle 18 to be jetted from the steam jet port 7. Blow out. Therefore, since the temperature of the steam injected from each steam injection port 7, 7'is lowered by the air, by appropriately selecting the nozzle 18 and each steam injection port 7, 7'inner diameter ratio, the flow rate of the sucked air can be reduced. It can be controlled and temperature can be controlled.

Further, since the positions of the steam injection ports 7 and 7'can be adjusted in this heat shrink device, it is possible to inject the steam from the most suitable position on the work surface of the workpiece a having various sizes and shapes. Alternatively, the position can be adjusted with the adjusting screw 15 so that the steam is sprayed in the most suitable spray range.

Although the present invention has been described above based on the embodiments of the drawings, the present invention is not limited to the above-described embodiments and can be carried out in any manner as long as the configuration described in the claims is not changed. it can.

<Effects of the Invention> As described above, according to the present invention, when the heat shrinkable work is difficult, for example, when the heat resistant temperature of the work is low,
Even when there is complicated printing on the heat-shrinkable film, distortion, curvature, wrinkles, air blisters, it is possible to adhere the heat-shrinkable film to the work piece without causing color unevenness of printing, Further, the work piece is not deformed.

Then, for example, a cylindrical vinyl chloride film is adhered to the outer surface of the work piece of a cylindrical container made of a hard vinyl chloride having a diameter of 50 mm and a length of 200 mm, and the first position of the tunnel portion having a length of 250 mm is provided. Four steam outlets are provided at the top, bottom, left and right, and four steam outlets are provided diagonally above and below the second position. 100 ° C steam is jetted from each steam outlet to cover the vinyl film. 8
When heated to 0 ° C, the film becomes in close contact with the outer surface of the work piece simply by passing the work piece through the tunnel for 0.3 seconds. Then, if the temperature and time conditions as described above, only the film is sufficiently heated by steam to shrink, the film is not warped or curved because the surface of the workpiece is not sufficiently heated, and It is recognized that wrinkles do not occur.

Therefore, according to the heat shrinking method and apparatus of the present invention, the processing time is extremely short, and the heat-shrinkable film is shrunk only by heat-treating the work piece in the shape of a horizontal band along the moving direction. It becomes a close contact with and becomes a good appearance.

Further, even in the post-process after the processing, the energy and time consumed for drying the adhered water are the minimum for the wet method, which is of high practical value.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a schematic vertical sectional view of a heat shrinking device, FIG. 2 is a partial sectional view taken along line II-II of FIG. 1, and FIG. Fig. III-III Partial cross-sectional view, Fig. 4 is an explanatory view of a state in which steam is sprayed on a part of the workpiece, and Fig. 5 is a state of steam sprayed on the entire surface of the workpiece. Explanatory drawing, FIG. 6 is a schematic front view showing a further embodiment of the present invention with a part thereof omitted, FIG. 7 is a sectional view of a part of line VII-VII in FIG. 6, and FIG. FIG. VIII is a partial cross-sectional view taken along the line VIII-VIII. 1 is a heat shrink device, 2 is an inlet opening end, 3 is an outlet opening end, 4
Is a tunnel part, 5 is a steam injection device, and 7 and 7'are steam injection ports.

Claims (2)

[Claims] 1. A workpiece, which is located on the axis of a tunnel portion having a plurality of steam injection ports, is moved in the longitudinal direction, and is adhered to the outer surface of the workpiece by the steam injected from each steam injection port. In the heat-shrinking method of heat-shrinkable film, the heat-shrinkable film is shrunk by heating. In the tunnel part, a plurality of steam injection ports are annularly arranged at a first position close to the entrance. At the same time, a plurality of steam injection ports are annularly arranged at a second position close to the outlet, and the steam injection ports at the second position are set to be positioned within the space between the steam injection ports at the first position. Then, the heat-shrinkable film is heated in the horizontal band shape along the moving direction of the work piece by the steam from the steam injection port at the first position, and the unheated portion is horizontally banded by the steam from the steam injection port at the second position. Heat shrinkable foil characterized by being heated to How to shrink the film. 2. A work piece positioned on the axis of a tunnel portion having a plurality of steam injection ports is moved in the longitudinal direction, and the work piece is adhered to the outer surface of the work piece by the steam injected from each steam injection port. In a heat-shrinkable film heat-shrinkable device that heats and shrinks a heat-shrinkable film, a plurality of vapor injection holes are annularly arranged at a first position near the inlet in the tunnel portion. At the same time, a plurality of steam injection ports are annularly arranged at a second position close to the outlet, and the steam injection ports at the second position are set to be positioned within the space between the steam injection ports at the first position. In addition, a steam supply mechanism is connected to each of the steam injection ports at the first position and the second position, and a conveyor mechanism is provided to convey the workpiece by positioning the workpiece on the axis of the tunnel portion. Heat shrink film heat shrink device.