JPS6029344B2 - Packaging material and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a packaging material and a method for manufacturing the packaging material.

As a packaging material, one in which a thermoplastic resin film is bent and a number of box-shaped depressions are provided therein is known.

Such packaging materials can be made by passing the film between rolls or pressing it in a press, but most have been made by pressurized air or suction molding. However, packaging materials made by these methods always have gaps between adjacent recesses. Moreover, the gap is usually large enough to occupy a considerable volume. However, if a noticeable gap is created between adjacent depressions, the packaging material will not be able to efficiently arrange the products. Therefore, a demand arose for packaging to be as compact as possible. The present invention satisfies these requirements. The inventor came up with the idea of not using a mold that provides box-like depressions or protrusions in air pressure molding or suction molding, but instead using a silk-like material.

Therefore, this inventor stretched a silk-like material above and parallel to the perforated plate used in pressure molding or suction molding, and then placed a film of thermoplastic resin softened by heating on top of the silk-like material. was placed on the film, and pressurized air was applied from above or suctioned from below to bring the film into close contact with the perforated plate, producing a film in which the entrance portion was locked by a net-like material. Furthermore, it was confirmed that the film thus produced met the above requirements. This invention was made based on such confirmation. The packaging material according to the present invention is composed of a net-like material and a thermoplastic resin film, the film is bent to form a number of box-like depressions that open on the same side, and the net-like material is formed at the entrance of the box-like depression. It is surrounded by a film that is folded back at the end of the entrance, and the adjacent box-shaped recesses are lined up without any gaps, so that the bottom of the box is located substantially on one plane. It is a packaging material.

Further, in the method according to the present invention, a silk-like material is held in a tensioned state and separated from a perforated plate, a thermoplastic resin film that has been softened by heating is placed on top of the silk-like material, and the thermoplastic resin film is heated from the top surface of the film. It is characterized by applying pressurized air and/or suctioning air from the lower surface to cause the film in a soft flattened state to protrude from the mesh toward the perforated plate, and to bring the protruding tip into close contact with the perforated plate. , relates to a method for manufacturing packaging materials.

Further, the method according to the improvement of the above method is a continuous version of the above method.

In this method, both sides of the mesh are fixed to tenters and kept apart from the perforated plate, and the silk and film are advanced by the movement of the tenter, and the silk is slid along the surface of the separator. The perforated plate is also moved in the same direction at a constant speed, and pressurized air is applied from the top of the film along the way.
and/or suction air from the lower surface of the film to make the softened film protrude from the mesh toward the perforated plate, bring the protruding tip into close contact with the perforated plate, and then cool the film to remove the film from the perforated plate. The present invention relates to a method for manufacturing a packaging material, which is characterized by separating the packaging material. The present invention will be explained as follows based on the drawings. Figure 1 shows
FIG. 1 is a partially cutaway perspective view of a packaging material according to the present invention. FIG. 2 is a sectional view showing one embodiment of the method of this invention. Third
The figure is a sectional view showing a further improved method of the present invention. In FIG. 1, 1 is a silk-like material, 2 is an opening in a box-shaped depression, 3 is a side wall of the box-shaped depression, and 4 is a bottom of the box-shaped depression.

Depending on how you look at it, the box-shaped depression in this packaging material can also be seen as a box-shaped protrusion, so in the explanation, the provision of the depression is sometimes referred to as protrusion, and the back of the bottom 4 is sometimes referred to as the tip of the protrusion. , ultimately refer to the same thing. The packaging material shown in FIG. 1 is composed of a net-like material 1 and a thermoplastic resin film.

The film is bent to form many box-shaped depressions that open on the same side. The box-shaped depression is located at the entrance 2 and the side wall 3.
, base 4. The silk material 1 is located in the opening 2,
It constitutes a core when the film is folded back at the entrance part 2. Therefore, the silk 1 is sandwiched between two adjacent side walls 3 and surrounded by the two side walls 3. Therefore, adjacent box-shaped recesses are lined up without any gaps, and most of their side walls are heat-sealed to each other. Furthermore, the side walls 3 in each recess have substantially the same height, and the back surface of the bottom 3 lies substantially on one plane. The packaging material shown in FIG. 1 can be used as a packaging material by placing a product in its recess.

In this packaging material, since the adjacent recesses are lined up without any gaps, the product can be placed without any gaps, and the product can therefore be packed well. In addition, since this packaging material has a net-like material sealed in the entrance part, it is reinforced by the silk-like material, so the packaging material should not be deformed or easily torn when pulled. ,
Packaging materials can be made stronger. In this respect, this packaging material has great utility value. The packaging material according to the present invention can be made by the method shown in FIG. In FIG. 2, 1 is a net-like material, 5 is a thermoplastic resin film, 6 is a perforated plate, and 7 is a perforated plate.
is a vacuum suction chamber. In the method shown in FIG. 2, the mesh 1 is first kept under tension and placed above and away from the perforated plate 6, so as to be parallel to the perforated plate 6.

Layering a heated and softened film 5 on top of the silk material 1,
These are placed on the suction chamber 7 together with the perforated plate 6. When the pressure inside the suction chamber 7 is reduced and the space between the film 5 and the perforated plate 6 is closed, the air between the film 5 and the perforated plate 6 is removed, and the film 5 is attracted to the perforated plate 6. At this time, since the net 1 is held away from the perforated plate, the part of the film in contact with the silk 1 is locked by the silk 1, and only the film between the meshes is perforated. It is attracted to the plate 6, and a box-shaped depression is formed there. The tip of the box-like projection rests in close contact with the perforated plate. In addition, between adjacent depressions, adjacent side walls are close to each other,
Most of the parts are thermally fused, and the bottoms of the recesses are lined up without gaps and form a flat surface. What is thus formed is a packaging material as shown in FIG. 1, which encloses the net-like material 1 therein and has a number of box-like depressions.

More specifically, in this packaging material, the film protrudes in the same direction from the mesh in the silk-like material to form a large number of box-shaped depressions, and the mesh is located at the openings of the box-shaped depressions. It is then wrapped in a film that is folded back at the entrance. Further, the box-shaped recesses are lined up without gaps and have side walls of substantially equal height, and the bottom hair of the box is lined up so as to substantially form one plane. Second
In the figure, a suction chamber 7 is provided below the perforated plate 6 to suck the film, but a pressurization chamber is provided above the film 5 and pressurized air is sent from the pressurization chamber, thereby causing the film 5 to be pierced. It may be pressed against the perforated plate 6. Further, suction and pressurization may be used together. Various thermoplastic resin films can be used as the film in this invention. Among them, ethylene resins, vinyl chloride resins, and styrene resins are most suitable. The thickness of the film is not limited to a thin film, which is commonly called a film, but may be one thickness or more, which is commonly called a sheet. As the silk-like material in this invention, not only ordinary binding nets but also any material in which a large number of thread-like materials intersect to form a network can be used.

However, the mesh of the silk-like material must be large enough to allow the film to protrude from the mesh. Also, the mesh of the silk material must be of a size suitable for containing the item to be packaged as a single mass. For example, in addition to fish nets, metal nets, plastic nets, etc., silk made by making cuts in plastic plates, metal lath, etc. can also be used. The shape of the mesh is not limited to a square, but may be a triangle or a polygon of pentagon or more A line etc. can be used.

As natural fibers, in addition to cotton, silk, etc., recycled fibers such as rayon and cupro can be used. Synthetic fibers include polyester, polyamide, polyacrylonitrile,
Pinilon etc. can be used. The intersection points of the filaments do not necessarily need to be fixed. When the material constituting the network is thermoplastic, it is desirable that its softening point be at least 100 to 190 degrees higher than the softening point of the film. In the method of the invention, in order to maintain the net under tension and position it above the perforated plate,
Use a tenter. That is, tenters are provided on opposite sides of the net, and the tenters are provided with clips at regular intervals, and the ends of the silk are fixed to the clips to hold them in tension, and the holes are Position it parallel to the board. Moreover, the method of this invention can also be performed continuously.

FIG. 3 shows the continuous method in cross-section. In FIG. 3, 1 and 7 represent the same items as shown in FIG. That is, 1 is a silk-like material, 2 is a closing part of a box-shaped recess, 3 is a side wall, 4 is a bottom, 5 is a thermoplastic resin film, 6 is a perforated plate, and 7 is a vacuum suction chamber. a is the traveling direction of the silk material 1 and the film 5, 8
is a heater, 9 is a separator, 10 is a hot air chamber, 11 is a cooling chamber,
12 is a take-up roll. In FIG. 3, a case will be specifically explained using an example in which a net made of cotton thread is used as the silk material 1 and a net made of polyethylene is used as the film 5.

The film 5 and the mesh 1 are continuously advanced in the direction of arrow a, and the film 5 is superimposed on the mesh 1.
At this time, the film 5 and the net-like material 1 are fixed at both ends to clips on the tenter, are maintained in a taut state, and are guided by the progress of the tenter to advance. A heater 8 is placed above the film 5, and the film 5 is
Heat to qo.

When heating, care must be taken so that the film 5 does not soften and sink into the mesh of the net-like material 1. At this time, the mesh 1 is cooled by the separator 9. The separator 9 has a jacket structure through which cooling water is circulated. The separator 9 not only separates the silk material 1 from the perforated plate by a certain distance, but also cools the silk material 1 from the underside so that the film 5
prevents it from sticking to surfaces. A perforated plate 6 is arranged below the separator plate 9.

The perforated plate 6 is subjected to a non-adhesive treatment so that its surface does not stick to the softened film 5, and is rotated like an endless belt. As mentioned above, the net-like material 1 is advanced by the tenter, so that the distance from the perforated plate 6 can be kept constant by moving the tenter a certain distance away from the perforated plate 6. However, by further sliding the mesh 1 on the separator 9, the distance is reliably kept constant. When the film 5 comes below the hot air chamber 10, 110 to 120 q○ of hot air is sent from the hot air chamber 10 and blown onto the film 5 to heat and soften the film 5.

Next, the perforated plate 6 is introduced into a reduced pressure suction chamber 7, and the pressure inside the suction chamber 7 is reduced to bring the film 5 into close contact with the perforated plate 6.

At this time, the net 1 is held in a tensioned state and is also held vertically away from the perforated plate 6, so that the portion of the film 5 that contacts the net 1 is held at that position together with the net 1. The remaining opening 2 is formed, and a portion of the film 5 in the vicinity thereof is stretched to form a side wall 3 standing between the mesh 1 and the perforated plate 6. Further, the film 5 located in the center of the mesh is made to protrude through the mesh and stops in close contact with the perforated plate 6. The side walls 2 standing on both sides of the opening 2 are in close contact with each other, forming a double side wall. In this way, box-shaped depressions are formed that are lined up without gaps.
In this case, most of the double side walls 2 are often heat-sealed into one piece, but not all of them are necessarily heat-sealed.

Heat fusing is not absolutely necessary. The recess is folded back at the closing part 2 and becomes continuous, and the net-like material 1 is enclosed in the folded part. Thereafter, the film 5 is transported to the bottom of the cooling chamber 11, where it is cooled by being blown with cold air, and the packaging material is completed here.

The packaging material is then separated from the perforated plate 6 and placed in a pair of rolls 1.
Taken over by 2. The roll 12 is an elastic roll whose surface is made of soft urethane foam. Therefore, even if the packaging material comes into contact with the roll 12, it will not be flattened. The above is polyethylene film 5
Although the explanation has been given by taking as an example the case where a net-like material 1 made of cotton thread is used, packaging materials can also be made by similar operations when using other resins and silk-like material.

In addition, in the above example, hot air was used only to heat the film 5, and the forming was performed by vacuum suction, but it is also possible to apply pressure to the hot air and perform hot air pressure molding, or by applying vacuum suction and pressurization. It can also be used in combination. Further, as the film 5, a film extruded from the T-die of the extruder and still in the softening machine can be used, and the heater 8 can be omitted. According to the method of this invention, a mesh material can be molded by air pressure molding, hot air molding, vacuum molding, or a combination thereof.

Furthermore, by performing the molding process once, a packaging material in which the recesses are closely spaced without gaps can be easily produced either continuously or intermittently. In this respect, the method of this invention has great practical value. Moreover, the packaging material of this invention is
When a thermoplastic resin film is laminated and adhered to the closed portion, a laminated sheet or a heat-insulating sheet with cushioning properties and provided with a large number of closed cell chambers can be obtained, so it can also be used for such purposes.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of a packaging material according to the present invention. FIG. 2 is a sectional view showing a concave embodiment of the method of the present invention. FIG. 3 is a sectional view showing a further improved method of the invention. In the figure, 1 is a mesh, 2 is an opening in a box-shaped recess, 3 is a side wall, and 4 is a bottom. 5 is a thermoplastic resin film, 6 is a perforated plate,
7 is a vacuum suction chamber, 8 is a heater, 9 is a separator, 10 is a hot air chamber, 11 is a cooling chamber, and 12 is a take-up roll. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. Consisting of a net-like material and a thermoplastic resin film, the film is bent to form a large number of box-like depressions that open on the same side, and the mesh-like material is formed in the openings of the box-like depressions. A packaging material in which the box-shaped recesses are located in the same position and surrounded by a film that is folded back at the open end, and the adjacent box-shaped recesses are lined up without any gaps so that the bottom of the box is located substantially on one plane. 2. Keep the net-like material under tension and separate it from the perforated plate, place a heat-softened thermoplastic resin film on top of the net-like material, apply pressurized air from the top surface of the film, and/or blow the film. A method for producing a packaging material, which comprises sucking air from the lower surface, causing the softened film to protrude from the mesh toward the perforated plate, and bringing the protruding tip into close contact with the perforated plate. 3 Fix both sides of the net to the tenter and keep them apart from the perforated plate, place a heat-softened thermoplastic resin film on top of the net, and move the net and film together by moving the tenter. At the same time, the net-like material is slid along the surface of the separator plate, and the perforated plate is also moved in the same direction at a constant speed, and pressurized air is applied from the top surface of the film along the way, and/or the net material is slid along the surface of the separator plate. The method is characterized in that the softened film is made to protrude from the mesh toward the perforated plate by suctioning air, the protruding tip is brought into close contact with the perforated plate, and then the film is cooled and separated from the perforated plate. ,
Method of manufacturing packaging materials.