JPS62290516A - Corrugated tubular film and manufacture thereof - Google Patents

Abstract

PURPOSE:To bring a novel visual effect to increase the visual value of a packed commodity and improve the working properties of bag making as well as bag- filling, by a method wherein, a tubular film is provided with corrugation by shaping continuous recesses and projections in the take-up direction thereof while cooling the film by water. CONSTITUTION:Air is sent into a molten synthetic resin tube 2, extruded from a die 1 with a diameter (a), through an air sending port 4 while passing it through an air ring 3 and providing a proper surface rigidity through cooling to inflate it until the diameter (b) is obtained, then, the tube 2 is passed through a water cooling ring 5 whereby the tube 2 is provided with a convergence. A multitude of flutes in the take-up direction of the same tube 2 is formed on the tube 2 by the convergence whereby the corrugated tubular film 2' with fine wave forms 2a may be obtained. The film 2' is passed further through a stabilizing plate 7, arranged below the water cooling ring 5, and is introduced into take-up rolls 8. The stabilizing plate 7 is constituted of two sheets of plate, which are opened at the introducing side of the corrugated tubular film 2' and closed at the take-up side of the same, while the film is reeled around a reeling roll 10 through the take-up rolls 8.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention Industrial Application Field The present invention relates to a corrugated tubular film that is a raw material for various packaging bags, sheet films, etc. made of synthetic resin film, and a method for manufacturing the same. .

Conventional technology and problems In general, there is a method to give a synthetic resin film an uneven shape by secondarily embossing the film and then forming it into a bag shape, but the number of processes is large and the cost is high. When the flat film is closed, a side seal portion is required, which impairs the aesthetic appearance.

Furthermore, Japanese Patent Publication No. 1983-28668 provides a method for providing the above-mentioned uneven shape during molding of a tubular film. This prior example uses a metal cooling ring as a cooling means for a molten synthetic resin tube extruded from a die, and it is important to note that when the tube passes through the metal cooling ring, the cooling rate is different between the contact area and the non-contact area. It was used.

In other words, since the contact part is rapidly cooled and solidified compared to the non-contact part, which cools slowly, the non-contact part is elongated and solidified somewhat longer in the drawing direction than the contact part, and the difference in length causes the same non-contact part to solidify. The principle is that a large number of ripple-shaped deformations occur in the contact area perpendicular to the pulling direction.

However, even if this ripple-like deformation can be expected to occur in accordance with the principle, it is equivalent to a kind of wrinkled wrinkle.
It also has technical problems, such as being unsightly and spoiling the appearance, and being dependent on unstable cooling rate differences and temperature differences, making it difficult to form uniformly at all times. Therefore, although the above-mentioned prior art discloses a means and method for adding a ripple pattern perpendicular to the drawing direction to a tubular film, there are difficulties in industrial implementation.

Purpose of the Invention The present invention provides a novel tubular shape with a sash-like corrugated shape that takes advantage of the characteristics of a synthetic resin film when applied as a packaging bag, and further enhances its individuality and creates a unique texture. Provide film. This corrugated tubular film has excellent features in both aesthetics and function as a raw material for packaging bags and the like.

The present invention does not require any unstable factors such as those in the preceding examples, such as differences in cooling temperature or cooling speed, which are bottlenecks in manufacturing.
The present invention provides a manufacturing method that allows a desired corrugated tubular film to be easily obtained by simple uniform cooling using a water-cooled solidification method that has already been proven in practical terms. To provide a tubular film having a shape that is continuous in the take-up direction and alternating in the circumferential direction, which is completely different from the shape of a continuous pattern with wrinkles as an element, and a method for producing the same.

The corrugated tubular film obtained by the present invention has the image of a packaging bag made from it as a raw material, and unlike packaging bags that were seen only from the side as a mere packaging means, it is a product that can be packaged. In addition to doubling the exhibition effect, by adopting the conventional inflation tube forming method and adding an idea regarding its application technology, the desired new corrugated tubular film can be easily and easily produced. This allows for highly reproducible production.

Structure of the Invention The present invention is a tubular film formed by water-cooling a molten synthetic resin tube extruded from a die,
A corrugated tubular film is provided by water-cooling the tubular film to form concavities and convexities that are continuous in the drawing direction.

Further, in the present invention, when a molten resin tube extruded from a die is cooled and solidified in a water-cooled ring, the inside of the water-cooled ring, which is smaller than the tube, is expanded while the tube is expanded. A method for manufacturing a corrugated tubular film in which the entire circumference of the molten resin tube is uniformly water-cooled and solidified with cooling water that flows out to the inner circumference of the water-cooled ring, and the entire circumference is formed with concavities and convexities that continue in the drawing direction to create a corrugated shape. I will provide a.

The present invention has made it possible to provide the desired corrugated tubular film as described above, and will be described below based on the illustrated embodiments.

Embodiment of the Invention As shown in FIG. 1, a molten synthetic resin tube 2 extruded from a die 1 having a diameter of 1 is air-cooled through an air ring 3 immediately after extrusion to give the tube 2 an appropriate surface rigidity, and the die 1 is cooled. Air is introduced through an air inlet 4 provided at the center to expand the tube 2 to its diameter, and the expanded molten synthetic resin tube 2 is passed through a water cooling ring 5.

This water cooling ring 5 has a cylindrical shape and has a diameter C smaller than the diameter of the expanded molten synthetic resin tube 2. On the other side, the water cooling ring 5 has an oval shape or the like. In this case as well, the inner circumferential length of the water cooling ring 5 is made smaller than the circumferential length of the expanded molten synthetic resin tube 2 as described above.

As described above, the expanded molten plastic tube 2 is passed through a smaller water cooling ring 5 to provide convergence. Due to this convergence, a large number of folds in the pulling direction are formed in the tube 2 in the circumferential direction. These folds become the pitch of the wave shaping period, which will be described later. The pitch of the pleats and wave shaping period depends on the difference between the degree of expansion of the molten synthetic resin tube 2 and the size of the water cooling ring 5.

As described above, the water cooling ring 5 is attached to the expanded molten synthetic resin tube 2.
At the same time, water is caused to overflow to the inner circumferential surface of the water cooling ring 5 as shown by the arrow, and the entire circumference of the convergence tube is brought into direct contact with cooling water to uniformly rapidly cool and solidify.

As a result of the above process, a corrugated tubular film 2' is obtained which has irregularities parallel to the drawing direction and is formed into fine corrugations 2a consisting of vertical valleys and peaks as a whole.

The corrugated tubular film 2' has a regular appearance in which the unevenness of the corrugations 2a has an amplitude and a period that does not visually show any variation.

The air ring 3 described above has its air discharge port oriented downwardly in the tube trading direction, and the air flow does not hit the tube at right angles, but flows diagonally downward along the tube. Providing appropriate surface rigidity to the fin contributes to the formation of complete fin folds.

The above corrugated tubular film 2' is further heated by a water cooling ring 5.
It is introduced into the take-up roll 8 through the stabilizer plate 7 arranged below it. The stabilizing plate 7 is formed by two plates that open on the introduction side of the corrugated tubular film 2' and close on the outlet side, and flattens the corrugated tubular film 2' by passing the stabilizing plate 7 through it. Fold over and take over roll 8
After that, it is wound onto a take-up roll 10. An embossing molding roll 9 is disposed on the exit side 1 of the stabilizing plate 7, for example, in front of the take-up roll 10 as shown in the figure, and the flattened corrugated tubular film 2' is heated while being molded. Press to partially erase the wave shape and partially form a flat part. This flat portion is a figure or the like, and exhibits a design effect in combination with the waveform 2a.

The corrugated tubular film obtained as described above was used as a raw material, and cut into equal lengths in the width direction in the take-up direction.
As shown in the figure, a packaging bag 2'' is obtained by applying the bottom seal 2b.This packaging bag 2'' retains the morphological characteristics of the tubular film, and has valleys and peaks parallel to the take-up direction. It has an appearance that is regularly formed in the shape of a blind in the circumferential direction, and this appearance and its light-reflecting effect, combined with the film's unique texture, create a unique design effect.

At this time, the bottom seal 2b contributes to maintaining the shape of the waveform 2a.

Regarding odor addition in the embodiment, a water tank 11 is provided as a water supply means for the water cooling ring 5 so as to surround its outer periphery, and cooling water 6 is constantly supplied to the water tank 11 from a cooling water supply 12 at a constant flow rate. , causing an overflow from the outside of the water cooling ring 5 to the inside of the water cooling ring 5 in an amount equal to the amount supplied.

As mentioned above, the overflowing water is forced by the inner diameter of the water cooling ring 5 to fall in a film form along the outer circumferential surface of the molten synthetic resin tube in a convergent state, and is rapidly cooled and solidified by contact with the convergent tube immediately after the overflow. urge

The expanded molten synthetic resin tube 2 is taken up at a constant speed by a take-up roll 3, and is forcibly drawn into the smaller water-cooled ring 5, where it forms numerous interdigital folds corresponding to the amount of expansion.

These folds are linear in the take-up direction and regular in the circumferential direction as described above, and the interdigital folds remain permanently as they are by rapid solidification by the water cooling, resulting in the above-mentioned wavy shape.

As an example, by rotating the water cooling ring 5 at an extremely low speed, the wave shape becomes a gentle spiral in the take-up direction depending on the rotation speed.

As the expanded molten synthetic resin tube 2 is taken up, this wave pattern spreads one after another, resulting in a continuous bc1a pattern extending over the entire length of the tube. Since this cooling and solidification is caused by direct contact cooling with cooling water, it occurs extremely rapidly, and the change from the molten state to the solidified state is completed near the upper end of the water cooling ring 5.

The water cooling ring 5 has a lip shape at the inlet of the expanding molten synthetic resin tube 2, as shown in the cross-sectional shape in FIG. A tapered lip 5b is formed on the inner circumferential surface of the lip 5b so as to be tapered upwardly. It is also effective to form periodic grooves 5C in the inner peripheral edge of the lip of the inlet of the water cooling ring 5, as shown in FIGS. 6A and 6H, for the purpose of defining the shape or arrangement of the waveform 2a. be.

The pitch of the waveform 2a in the above-mentioned wave shaping is determined by factors such as the diameter a of the die l, the diameter of the expanding molten synthetic resin tube 2, the inner diameter C of the water cooling ring 5, the thickness of the film, and the take-up speed. Determined.

The ratio of the diameter of the molten synthetic resin tube 2 to the inner diameter C of the water cooling ring 5 is suitably within the range of 1.10 to 1.70.

Waveform 2a cannot be shaped below 1.05, and 1.80
In this case, the difference in the unevenness of the waveform 2a is too large, and there is a risk that folded wrinkles may occur on the original surface at the take-up roll portion, or that the periodic intervals of the unevenness of the waveform 2a may become irregular.

The optimum ratio value varies depending on the type of resin, the thickness of the film, the take-up speed, etc., but by setting it within the above range, good wave shaping can be achieved. It is not necessarily necessary that the diameter of the molten synthetic resin tube 2 is larger than the diameter a of the die l, but even under manufacturing conditions such as baa, so-called deflation, the above can be achieved by appropriately setting b/c. The wave shape is impossible and it is a cane.

Next, an experimental example of the present invention performed in accordance with the above explanation will be described.

Experimental example-1 Low-density polyethylene resin was extruded through a die with a diameter of 100 cmφ, the resin tube diameter was expanded to about 70 mmφ, and the resin tube was passed through a water cooling ring with an inner diameter of 54 mm at a drawing speed of 13 particles/min. The original fabric with a thickness of 80 mm and a folded diameter of 85 m1 is S! When fabricated, a concavo-convex shape with eight periods was formed on one side that was continuous in parallel to the pulling direction.

Experimental example-2 Polypropylene resin for inflation 100 mm
It was extruded from a die with a diameter of φ, expanded to a resin tube diameter of about 851φ, and passed through a water cooling ring with an inner diameter of 81 m layers at a take-up speed of 20 mm/min.
When the original fabric was produced, a concave and convex shape with 13 periods was formed on one side that was continuous in parallel to the take-up direction.

Experimental example-3 A two-layer combination of inflation polypropylene resin for the outer layer and low-density polyethylene resin for the inner layer is extruded from a two-layer die with a diameter of 1001φ at an extrusion ffuii ratio of 25% for the outer layer and 75% for the inner layer, and the resin tube diameter is approximately 120 ms + φ. It was expanded to 801L in thickness and passed through a water-cooled ring with an inner diameter of 93mmφ at a take-up speed of 12 layers and 7 minutes, with a folded diameter of 150m5.
When the original fabric was manufactured, a concavo-convex shape with 27 periods was formed on one side that was continuous in parallel to the take-up direction.

Experimental example-4 Outer layer 3 is a combination of three layers: nylon resin for the outer layer, modified polyethylene adhesive resin for the middle layer, and low-density polyethylene for the inner layer.
5%, middle layer 20%, and inner layer 45% extrusion weight ratio through a three-layer die with a diameter of 120 @■φ, expand the resin tube diameter to about 240 amφ, and make an inner diameter of 190 amφ.
When a raw fabric with a thickness of 80 IL and a fold diameter of 300 m5 was produced by passing through a water-cooled ring at a take-up speed of 13 m/min, an uneven shape with 60 cycles was formed on one side that continued parallel to the take-up direction.

Experimental example-5 Extrusion from a three-layer die with a diameter of 80 mm with the three-layer configuration described in 1.
Expand the resin tube diameter to about 401φ and make the inner diameter 32m.
It passes through a 5φ water cooling ring at a drawing speed of 20μ/min.
When we produced an original intestine with a thickness of 80 #L and a folded diameter of 50 m,
A concavo-convex shape with 16 cycles was formed on one side that continued parallel to the take-up direction.

Effects of the Invention The corrugated tubular film according to the present invention has regular parallel peaks and troughs in the longitudinal direction, and in combination with the film texture, it has a unique light effect due to the added shape. It creates a reflective effect, creates a unique appearance that echoes the image of conventional flat tube film, brings a novel visual effect that cannot be obtained with flat tube film, and significantly increases the visual value of packaged products. It can be effectively used as a form of packaging.

In addition, there is no phenomenon of close contact between the inner surfaces of the bag or between the outer surfaces, which is often seen with flat tubular films.Furthermore, the rigidity of the bag is strengthened by the above-mentioned periodic wave formation, and even flexible materials can be It has the effect of being able to have rigidity and uprightness, and as a result, suitability for bag making processing, suitability for bag filling work, and suitability for packaging equipment are significantly improved.

As described in the experimental examples, the present invention can be applied to all single-layer or multi-layer resin films that can be produced by the direct water-cooling inflation method.

The method of the present invention does not require any special equipment, and can mass-produce tubular films that are corrugated in parallel to the drawing direction by utilizing conventional inflation molding equipment, and does not involve difficult settings such as temperature differences. A homogeneous wave shape can be stably formed.

In addition, the corrugated tubular film according to the present invention, which is shaped into a periodic uneven shape parallel to the take-up direction, can be processed into bags as it is in the tube shape and used as various packaging bags, and can also be cut open and made into flat sheets. It can also be used as a base film for target films. In addition, it can be used not only in its natural color state but also as a colored original fabric by adding a coloring agent.

[Brief explanation of drawings]

FIG. 1 is a side view showing an outline of the apparatus used in the manufacturing method of the present invention, FIG. 2 is a perspective view showing the main parts of a corrugated tubular film, and FIGS. 3A to 3A are A of FIG. -A', B-B
', c-c', D-D' sectional view, 4th. FIG. 5 is a sectional view showing the main part of an embodiment of the opening shape of the water cooling ring, FIG. 6A is a plan view showing the other side of the opening shape of the water cooling ring, and FIG. FIG. 7 is a partially cutaway side view of a packaging bag made of corrugated tubular film as a raw material. l... die, 2... molten synthetic resin tube, 2'.
...Corrugated tubular film, 2a...Corrugated, 5.
...Water cooling ring, 6...Cooling water, a...Die diameter, b...Diameter of expanding molten synthetic resin tube, C...
Inner diameter of water cooling ring. Patent Applicant: Krylon Kasei Co., Ltd. Representative, Patent Attorney: Takashi Nakahata Figure 1 Figure 2 (C) 2”

Claims (2)

[Claims] (1) A tubular film formed by water-cooling a molten synthetic resin tube extruded from a die, in which a large number of uneven stripes are formed alternately in the circumferential direction and continuous in the drawing direction. A corrugated tubular film characterized by being corrugated. (2) While expanding the molten synthetic resin tube extruded from the die, it is passed through a smaller water-cooled ring to give convergence, and at the same time, the entire circumference of the converged molten synthetic resin tube is cooled to flow into the inner circumference of the ice-cooled ring. A method for producing a corrugated tubular film characterized by uniformly cooling and solidifying with water and forming a large number of concave and convex stripes on the entire circumference that are alternate in the circumferential direction and continuous in the drawing direction to form a corrugated shape.