JPH0528015Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a radiant heating oven for synthetic resin films. More specifically, the present invention relates to improvements in a radiant heating oven used to convert synthetic resin films into objects through various operations such as stretching, heat setting, coating, and lamination.

"Prior Art" An indirect heating method is employed when preheating, heating, or heat treating a synthetic resin film to a predetermined temperature in order to convert it into a target object through the various operations described above.

One of the indirect heating methods is the hot air heating method.
This hot air heating method is a method in which heated air is blown onto a synthetic resin film to heat the film (for example, JP-A-51-91973, JP-B-Sho.
(See Publication No. 36851, etc.) When using this method, the temperature of the hot air and the temperature of the film are very close to each other, so temperature control is relatively easy, there is little influence from the outside air temperature outside the heating furnace, and temperature accuracy is high. However, when this method is used, the film tends to unravel, and the film heated close to the softening temperature of the resin causes local distortion, resulting in so-called "flare" and unevenness on the film surface when the product is unwound. and reduce the quality of the product. Furthermore, if the film is extremely thin, it may break due to flaps.

Another type of indirect heating method is a method that heats the film by irradiating it with electromagnetic waves in the infrared or far infrared region (for example,
(See Publication No. 39932). This method (a) allows heating ovens to be used at low cost. (b) While the heating oven has advantages such as easy maintenance, (c) it is easily affected by the outside air surrounding the heating oven, and (d) it has poor thermal efficiency.
(e) There were drawbacks such as the tenter clip overheating abnormally and the film in this area being prone to tearing.

That is, when preheating, heating, or heat-treating the film to a predetermined temperature using an infrared source in a heating oven equipped with tenter clips,
Film heating is performed not only by infrared energy radiation, but also by convection between the film and the surrounding air. There are the following problems.

As the tenter clip travels through the oven at high speed, outside air is drawn into the oven and the air surrounding the film is disturbed. As a result, the influence of air convection on the temperature of the film is significantly large. Furthermore, since the tenter clip is cooled to prevent softening and breakage of the gripped portion of the synthetic resin film, the effect of the tenter clip running at high speed on the temperature of the film is further exacerbated. Cooling is performed by water cooling the tenter rail, by air cooling the tenter rail on the return side that does not grip the film, or by both.

In heating where radiation and convection coexist, the temperature of the film near the periphery of the infrared source tends to decrease. This is due to air convection. In a heating oven equipped with tenter clips, the influence of air convection on the temperature of the film is extremely large, as described above, so that the above-mentioned tendency of temperature decrease is further exacerbated.

In particular, the disadvantage of (e) is that the film is heated continuously,
It must be eliminated because it not only causes problems when it is used as a target object, but also significantly reduces the commercial value of the target object.

``Problem that the invention was trying to solve'' This invention aims to preheat the synthetic resin film to a predetermined temperature in order to make it into a desired product through processing methods such as biaxial stretching, heat setting, heat relaxation, coating, and lamination. Another object of the present invention is to provide a heating oven that does not overheat tenter clips during heating, does not easily tear the film, and has excellent thermal efficiency.

``Means for Solving the Problem'' The gist of the present invention is to provide an oven that heats a synthetic resin film using a radiation heating method. A clip is installed that runs while being guided by a rail while gripping both ends in the width direction, and an infrared heater is installed above the running synthetic resin film so that it is wider than the width of the running synthetic resin film. The tenter rail that guides the tenter clip is arranged so that it can approach and retreat from the center line of the running synthetic resin film, and the tenter rail that guides the tenter clip covers the tenter clip and has one end running. A radiant heating oven for synthetic resin film is characterized in that a cover for tenter clips is installed that extends close to the synthetic resin film and is longer than the length of the infrared heating heater.

In the present invention, synthetic resin refers to all thermoplastic resins that can be made into a film. Specifically, styrene resins, vinyl chloride resins, olefin resins, polyamides, polyesters, acrylic resins, fluorine resins, silicone resins, polycarbonates, polyvinyl alcohol, polyacetals,
Examples include polysulfone and polyphenylene oxide, but are not limited to these examples. Film is anything from 0.5 microns to several millimeters thick.

The radiation heating oven according to the present invention can be applied when biaxially stretching a synthetic resin film, when applying heat fixation or heat relaxation after stretching a crystalline film, and when applying a coating liquid to the film and drying it. This is when heating the film, such as when laminating a laminate on the film.

The present invention will be described in detail below with reference to the drawings, but the present invention is not limited to the following examples as long as it does not deviate from the gist of the invention.

FIG. 1 is a partially cutaway longitudinal sectional front view of an example of a radiant heating oven according to the present invention, FIG. 2 is an enlarged longitudinal sectional front view of a tenter clip portion, and FIG. FIG. 4, a longitudinal sectional front view of another example, is a partially cutaway perspective view showing the fixing state, positional relationship, etc. of the heat ray reflecting plate.

In the figure, 1 and 31 are synthetic resin films, 2 and 32 are tenter clips, respectively.
3 and 33 are heating heaters, 4 and 34 are heater insulation walls, 5 and 35 are tenter rails, 6 and 36 are covers for tenter clips, 7 and 37 are tenter rail stands, and 8 and 38 are tenter rails, respectively. Rail gap adjustment screw rods, 9 and 39 are handles, 10 and 4, respectively.
0 are connection bearings, 11 and 41 are fixed legs, 12 and 42 are heating oven covers, 13 is a tenter chain, 14 is a fixed shoe, 15 is a tenter clip cover support rod, and 4
3 and 44 are heat ray reflecting plates, 45 is a support,
46 is the fixing bolt, a is the gap between the end of the tenter cover and the synthetic resin film, b and c are the gaps between the inner surface of the tenter clip cover and the tenter clip, and a is the two overlapping heat ray reflecting plates. The part shown is shown below.

The radiation heating oven according to the present invention has a substantially rectangular parallelepiped shape that is elongated in the direction in which the synthetic resin film runs and is substantially parallel to the floor surface. The synthetic resin film is held almost parallel to the floor surface at both ends with tenter clips, inserted into a rectangular parallelepiped radiant heating oven from one end in the longitudinal direction, and run through the radiant heating oven. During this time, it is heated to the desired temperature and discharged from the other longitudinal end.

The radiant heating oven according to the present invention has tenter clips that grip both ends of a synthetic resin film on the sides corresponding to the longitudinal direction of the almost rectangular parallelepiped oven so that they can run while being guided by tenter rails. Install.

As shown in a longitudinal sectional front view in FIG. 1, the tenter clip grips both ends of the synthetic resin film 1 in the width direction and stretches the synthetic resin film while traveling guided by the tenter rail 5. , utilized to provide relaxation.

The tenter clip may have any structure as long as it can grip the end of the synthetic resin film while being guided along the tenter rail by the tenter chain, for example, as shown in Fig. and Figure 11, Figures 1 and 3 of Japanese Patent Publication No. 55-30977, Figures 2 and 3 of Japanese Patent Publication No. 56-32089, Figure 12 of Japanese Patent Publication No. 57-36853, etc. The one listed will be used.

The tenter chain that guides the tenter clip is shown in Figure 1 of Utility Model Publication No. 46-19426, and in Japanese Patent Publication No. 1973.
The structure illustrated in FIG. 12 of Japanese Patent No. 36853 is preferably used.

As shown in FIG. 1, the tenter rails are arranged on both side surfaces along the length of a substantially rectangular parallelepiped oven. The structure of the tenter rail is
It is preferable to have a cross section as shown as 5 in FIG. The arrangement of this tenter rail is
Although it depends on the purpose of use of the radiation heating oven, when stretching a synthetic resin film biaxially or in the transverse direction, it is recommended to
It is preferable to do as shown in Figure 11 of Japanese Patent Publication No. 55-30977 and Figure 1 of Japanese Patent Publication No. 56-32089. When heat-setting a synthetic resin film, it is best to arrange the pair of tenter rails parallel to each other, and when performing relaxing heat treatment, it is best to arrange them so that the synthetic resin film travels inlet side is wide and exit side is narrow. .

To change the distance between the pair of tenter rails depending on the purpose of use, the tenter rails are arranged so that they can approach and retreat from the center line of the synthetic resin film running on the tenter rails. The spacing between the tenter rails is determined by placing the tenter rail 5 on a tenter rail stand 7, screwing the tenter rail gap adjusting threaded rod 8 installed on the tenter rail stand 7 into the connecting bearing 10 at the bottom of the tenter rail 5, and then tightening the handle 9. It is better to be able to change it by turning. To do this, the tenter rail 5 should be
As shown in FIG. 1 of Japanese Patent No. 19426, it is preferable to divide it into a plurality of parts and connect them using joints.

In the radiant heating oven according to the present invention, a heating heater is arranged above a traveling synthetic resin film. This heater functions to heat the synthetic resin film running in the oven.
As will be described later, a box-shaped heater cross-section wall covering the heater is placed above the heater, and both ends of the heater insulation wall are
As will be described later, the tenter clip cover is positioned above the top plate of the tenter clip cover with a small gap therebetween.

As for the heating heater, long heaters are arranged parallel to the running direction of the synthetic resin film, or multiple short heaters are arranged parallel to the running direction of the synthetic resin film.
Any method may be used, such as forming a row of a plurality of rods perpendicular to the running direction, and arranging the rows in a plurality of rows in the running direction so as to form a long length as a whole. In either case, the width of the portion where the heater is arranged is made larger than the width of the synthetic resin film being run.

As mentioned above, by installing the heater wider than the width of the running synthetic resin film, it is possible to heat a wider area around the film where convection has a significant cooling effect.
Moreover, even when the tenter rail approaches or retreats from the center line in the film running direction,
A minute gap is formed between the heater and the tenter clip cover, which will be described later, so that the air between the heater, the tenter clip cover, and the film can be maintained in a semi-sealed state, and the temperature of the film can be stabilized.

Examples of the heater include an infrared lamp and an infrared heater. The heater is installed above the moving synthetic resin film in order to prevent the synthetic resin film from burning or burning if it breaks or sags due to overheating. . Another purpose is to minimize the natural convection of air in the above-mentioned semi-closed structure including the film.

The heater is disposed under a box-shaped heater heat insulating wall facing downward, and the inner surface of the heater heat insulating wall is preferably smooth so as to reflect heat rays. In addition, the edge of the side surface parallel to the running direction of the synthetic resin film of the heater insulation wall is
It is arranged to reach the top of the tenter clip cover. In this way, it is possible to prevent the radiation heating oven from releasing heat, thereby improving thermal efficiency.

The radiant heating oven according to the present invention is provided with a tenter clip cover having a top plate substantially parallel to the floor surface in order to prevent the tenter clip from overheating. This tenter clip cover covers the tenter clip and prevents the temperature from rising due to heat from the heater, reflected heat from the synthetic resin film, and reflected heat from the future when a heat ray reflector is installed. fulfill a function.

If the tenter clip cover is placed in the heating oven on both the outward and return sides of the tenter rail, the cut surface cut at right angles to the length direction should be of the type shown as 6 in Figure 1. It is better to If only the outward path of the tenter rail enters the heating oven, a mold such as that shown at 36 in FIG. 3 may be used. Since the upper side of the tenter clip cover is almost parallel to the floor surface, even if the gap between the tenter rails is changed, the gap formed between the side edge of the heater insulation wall and the upper side of the tenter clip cover does not change. This will help prevent heat from escaping from the oven.

The tenter clip cover has one end extended to the vicinity of the running synthetic resin film and longer than the length of the heating heater, and is fixed to the tenter rail. The gap a between the end of the tenter clip cover and the synthetic resin film (see Figure 2) is preferably in the range of 1 to 2 cm, and the gaps b and c between the inner surface of the tenter clip cover and the tenter clip (see Figure 2) are preferably in the range of 1 to 2 cm. (see Figure 2) are 1 to 1, respectively.
A range of 2 cm is recommended.

The cover for the tenter clip is divided into the same number of parts as the tenter rail is divided into multiple parts, the lengthwise end is overlapped with the other part adjacent to it, and the cover for the tenter clip is fixed to the tenter rail with a support. Even if the gap between the rails is partially changed, it is preferable to combine the tenter clip covers so that there is no gap between the overlapped longitudinal ends of the tenter clip covers.

The tenter clip cover reflects heat rays,
It is best to choose a material that can maintain its shape even under high temperatures; specific examples include stainless steel plates and aluminum plates. The cover for the tenter clip may be a composite material with a heat insulating material sandwiched inside, or may be a material in which a heat insulating material is bonded to a metal plate and this surface is located inside the cover.

The radiation heating oven according to the present invention is as described above, but in order to improve thermal efficiency, a heat ray reflecting plate can be placed below the traveling synthetic resin film. This heat ray reflecting plate reflects the heat rays that have passed through the synthetic resin film, irradiates the synthetic resin film again, and serves to maintain the airtightness of the radiant heating oven.

The heat ray reflecting plate is composed of a long metal plate, parallel to the surface of the running synthetic resin film, and
It is preferable that the synthetic resin film can be divided substantially parallel to the center line of travel of the synthetic resin film, and the divided ends should be placed one on top of the other without leaving any gaps.

FIG. 3 and FIG. 4 show a state in which two plates of the longitudinal section of the heat ray reflecting plate are exposed. As shown in FIGS. 3 and 4, the heat ray reflecting plates 43 and 44 are attached to supporting tools 4 on opposing rails 35, respectively.
5 and a fixing bolt 46,
The divided ends of each are overlapped at the A part without leaving a gap. The heat ray reflecting plates 43 and 44 are not formed of a single plate, but are attached to the tenter rail 3.
It is preferable to have a structure in which the synthetic resin film is divided into a plurality of pieces along the running direction according to the division mode No. 5, and the ends of the synthetic resin film along the running direction are overlapped.

The heat ray reflecting plate should preferably have a rigidity that reflects heat rays and maintains a planar shape, such as an aluminum plate, a stainless steel plate, or a metal-deposited steel plate, all of which should be smooth and mirror-like. preferable.

The radiant heating oven according to the present invention is as described above, and in order to further reduce the influence of outside temperature, it is preferable to cover the entire radiant heating oven with a heating furnace cover.

"Effects of the invention" As described above, the invention has particularly remarkable effects as described below, and its practical utility value is extremely great.

(1) The radiant heating oven according to the present invention can
The spacing between tenter rails can be easily adjusted. At this time, since the width of the heater portion is made wider than the width of the synthetic resin film being run, it can be used for multiple purposes.

(2) In the radiant heating oven according to the present invention, the heating heater is placed above the running synthetic resin film, so even if the film sag due to overheating, it will not burn or burn.

(3) In the radiant heating oven according to the present invention, since the tenter clip is covered with the tenter clip cover, the tenter clip does not become abnormally overheated, and the film near the tenter clip is less likely to be torn.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway longitudinal sectional front view of an example of a radiant heating oven according to the present invention, FIG. 2 is an enlarged longitudinal sectional front view of a tenter clip portion, and FIG. FIG. 4, a longitudinal sectional front view of another example, is a partially cutaway perspective view showing the fixing state, positional relationship, etc. of the heat ray reflecting plate. In the figure, 1 and 31 are synthetic resin films, 2 and 32 are tenter clips, respectively.
3 and 33 are heating heaters, 4 and 34 are heater insulation walls, 5 and 35 are tenter rails, 6 and 36 are covers for tenter clips, 7 and 37 are tenter rail stands, and 8 and 38 are tenter rails, respectively. Rail gap adjustment screw rods, 9 and 39 are handles, 10 and 4, respectively.
0 are connection bearings, 11 and 41 are fixed legs, 12 and 42 are heating oven covers, 13 is a tenter chain, 14 is a fixed shoe, 15 is a tenter clip cover support rod, and 4
3 and 44 are heat ray reflecting plates, 45 is a support,
46 is the fixing bolt, a is the gap between the end of the tenter cover and the synthetic resin film, b and c are the gaps between the inner surface of the tenter clip cover and the tenter clip, and a is the two overlapping heat ray reflecting plates. The part shown is shown below.

Claims (1)

[Claims for Utility Model Registration] (1) In an oven that heats a synthetic resin film using a radiation heating method, the oven is equipped with tenter rails that hold the synthetic resin film at both ends approximately parallel to the floor surface. A tenter clip that runs while being guided by the tenter clip is placed, the tenter clip is covered with a cover for the tenter clip that has a top plate that is almost parallel to the floor, and a synthetic resin heater that runs is placed above the running synthetic resin film. The heater is installed with a width wider than the film width, and a box-shaped heater insulating wall that covers the heater is placed above the heater, and both ends of this heater insulating wall are placed above the top plate of the tenter clip cover. A radiant heating oven for synthetic resin film, characterized in that the tenter rail for guiding the tenter clip is arranged so as to be able to approach and retreat from the center of the running synthetic resin film. (2) The feature is that the gap between the inner surface of the tenter clip cover and the tenter clip is 1 to 2 cm, and the gap between one end of the tenter clip cover and the running synthetic resin film is 1 to 2 cm. A radiant heating oven according to claim (1) of the utility model registration.