JPH0298516A - Method of cutting film in vacuum tight packaging and cutting board therefor - Google Patents

Abstract

PURPOSE:To cut off a superfluous film efficiently and safely by placing an article to be wrapped on a film cutting board consisting of hot wires with a lower film interposed therebetween, covering from above the article tightly with an upper film softened by heating in a vacuum and thereafter energizing the hot wires. CONSTITUTION:An article (b) to be wrapped is placed on a lower film (f). A cutting board 7 is then moved down into a lower chamber 2 and an upper film (g) fed from a film roll 13 provided thereby is laid over an opening of the lower chamber 2. An upper chamber 1 is moved down into a close fit with the lower chamber with the edges of the upper film (g) pressed therebetween to keep a chamber (a) airtight and a heating plate 6 is moved down close to the upper film (g) to evacuate the chamber (a). After the upper film (g) is sufficiently heated to become soft, the heating plate 6 is moved upward and, at the same time, the cutting board 7 is moved up to the opening level of the lower chamber 2 to permit the external air to enter into the chamber (a). With the already wrapped article placed on the cutting board 7, hot wires (h) are energized for heating through a terminal and lead wire.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to vacuum tight packaging, more specifically, to a film cutting method in a packaging technique in which a lower film and an upper film are vacuum bonded from above and below an object to be packaged, and this method. This relates to a cutting board used for.

(Prior art) Conventionally, a method has been used in which a tray containing items to be packaged is placed on a board, a heated and softened upper film is tightly wrapped over the tray, and then the film is cut by hot wire along the periphery of the tray. It is disclosed in Japanese Patent Publication No. 54-43952.

On the other hand, in packaging technology in which the lower film and the upper film are vacuum-adhered from the top and bottom of the packaged item without using a tray, this method of thermally cutting and removing excess film from the packaging has not been used in the past. do not have. In other words, in such packaging technology, since the lower film is not in close contact with the cutting board, air flows in at the same time as cutting, causing the product to float.
The power of film, soto, was thought to be impossible.

Therefore, in vacuum seal packaging using a lower film and an upper film, after packaging, the package molded product is taken out and the excess film is manually cut off using a knife, scissors, press cutter, or the like.

(Problem to be solved by the invention) However, it is extremely time-consuming and inefficient to manually cut off excess film each time. Mechanical cutting can cause vacuum leaks from the wrinkles in the packaging film, and it is also dangerous because it requires handling a knife, and it takes time to get used to it.

Therefore, the purpose of the present invention is to solve the above technical problems,
To provide a means for efficiently and safely cutting off excess film in vacuum tight packaging using a lower film and an upper film.

(Means for Solving the Problems) The object to be packaged was placed on a cutting board equipped with a film cutting means consisting of a hot wire, with the lower film interposed therebetween, and the heated and softened upper film was vacuum-tightly packaged from above. rear,
A film cutting method for vacuum tight packaging is configured in which a hot wire of a cutting board is energized to heat-melt and cut the film.

To be used in this method, a cutting board was constructed with a flat top surface and a hot wire attached thereto.

(Function) In the present invention configured as described above, by energizing the hot wire of the cutting board, the hot wire generates heat, and the film near the hot wire is thermally melted.

Since the film tends to shrink when heated, shrinkage stress is generated within the film and the film is cut at the melted portion.

(Example) The present invention will be explained in detail below.

First, a packaging device 1k (A) for vacuum tight packaging will be described.

In Figure 1.2, (a) is the chamber, (1) and (
2) is an upper chamber and a lower chamber that constitute the chamber (a), and a packing (3) is provided at the abutting part of the upper chamber (1) and the lower chamber (2), which protects the chamber. When closed, the inside of chamber (a) is kept in a sealed state.

The upper chamber (1) is movable upwards, thereby allowing chamber (a) to be opened.

Vacuum pipes (4) and (5) are connected to the upper chamber (1) and lower chamber (2), respectively, so that a vacuum device (not shown) can be operated to create a vacuum inside the chamber (a). It has become. In addition, the upper chamber (1)
The lower chamber (2) may be communicated with the lower chamber (2), and the vacuum pipe may be connected to only one of the chambers.

(6) is a heating plate that is movable up and down in the upper chamber (1), and (7) is a cutting board that is movable up and down in the lower chamber (2).

As shown in Fig. 3A, hot wires (h) are attached to the top surface (7') of this flat cutting board (7). Each terminal (8
)... are connected to the terminals (10) (10) at the end of the cutting board (7) by the lead wire (9) inserted through the cutting board (7).
It is connected to the.

The hot wire (h) is made of electrical resistance wire such as nichrome wire or tungsten wire, and is connected to the top surface (7) of the cutting board (7).
It is supported by a support ring (12) fixed to a heat insulating part (11) buried in the hole 1) to maintain the desired shape. (See Figure 3, C) 9. If the top surface (7') of the cutting board (7) is coated with something to make it adhere well to the film, such as polyurethane resin, and the support ring (12) is made low, There is no inflow of air when cutting the film, which will be described later, and the cutting can be performed satisfactorily.

Each hot wire (h) is equal to two hot wires (hl) (h2
) are crossed to form a seamless loop, and by connecting the lead wire (9) to both of these two hot wires (hl) and (h2) and energizing them, the hot wire (h) This prevents any uncut edges from being left on the film being fused.

Next, vacuum tight packaging using the packaging machine (A) configured as described above will be explained with reference to FIG. 4.

First, the upper chamber (1) is moved upward to form the chamber (a
), spread the lower film (f) with the cutting board (7) raised by the opening of the lower chamber (2), and place the packaged item (b) on top of this lower film (f). (See Figure 4 A).

At this time, it is necessary to place the item (b) to be packaged with some space so that it does not protrude from inside the heating wire (h) attached to the cutting board (7).9 Next, place the cutting board (7) in the lower chamber. (2) Lower the upper film (
g) on the opening surface of the lower chamber (2) (opening in the figure).

Next, lower the upper chamber (1) and close the upper and lower chambers across the edges of the upper film (g) stretched over the opening of the lower chamber (2) to seal the inside of the chamber (a). , heating plate (6
) is lowered close to the upper film (g), and in this state, the inside of the chamber (a) is evacuated via the vacuum pipes (4) and (5). (Figure C).

In addition, when pumping, the pumping speed of the upper chamber (1) is compared to that of the lower chamber (2).
If the upper film (g) is brought into close contact with the heating plate (6) due to the internal pressure difference between the two chambers, the upper film (g)
can be reliably softened by heating. In addition, a heating plate (
By making the width of the heating plate (6) slightly smaller than the inner width of the upper chamber (1) to form a gap for air to pass through, or by drilling a large number of air vent holes on the surface of the heating plate (6), the upper film can be removed. The air between (g) and the heating plate (6) can be quickly removed, allowing the upper film (g) to come into closer contact with the heating plate (6)9.Then, the inside of the chamber (a) is vacuumed. condition, and place on a heating plate (
After the upper film (g) is sufficiently heated and softened by step 6), the heating plate (6) is raised and the cutting board (7)
When the film is raised to the opening of the lower chamber (2) and air is introduced into the chamber (a) in this state, the heated and softened upper film (g) is transferred to the lower film spread on the cutting board (7). (f) wraps the packaged item (b) in close contact, and the upper and lower films become one body where there is no packaged item (b) (FIG. 2).

Furthermore, if the inflow velocity of the upper chamber (1) is made faster than that of the lower chamber (2) when air inflows, there is no fear of air entering between the upper film (g) and the lower film (f). Packaging is done well.

Next, while the packaged product is placed on the cutting board (7), a hot wire (h) is passed through the terminal (10) and the lead wire (9) to heat it.

Then, the upper and lower films near the heating wire (h) are thermally melted, and as the film shrinks due to heating, the film is cut along the periphery of the packaged item (b) as shown in FIG. 5.

Then, move the upper chamber (1) upwards and move the chamber (
Open a) and take out the packaged product (see Figure 4 E).

As a result, a suitable product in which the excess film is removed and only the necessary parts are packaged can be easily obtained.

According to the vacuum tight packaging as described above, the object to be packaged (b) is not heated by the heating plate (6), and even living things, frozen foods, etc. can be packaged.

Furthermore, even if there is a gap between the upper and lower films due to wrinkles, there is no need to worry about vacuum leakage as the cut portion of the film is heat welded. Five elongated hexagonal heating wires (h) are provided, but their size, shape, number, etc. can be determined to suit the shape and size of the item to be packaged, and various types can be used. be.

Furthermore, it is not always necessary to make each heating wire (h) an independent shape; for example, as shown in FIG. However, it may take any other shape.

By preparing in advance several cutting boards with different shapes of hot wires and exchanging them, it is easy to package items that match the shape and size of the packaged item.

(Effects of the Invention) In any case, according to the present invention, in a device that vacuum-adheres a lower film and an upper film from above and below of an object to be packaged, excess film on the packaging can be thermally cut and removed. Therefore, it is efficient because it saves the labor of manually cutting off excess film as in the conventional method.

Further, since there is no need to handle cutlery, it is safe, and good quality packaged products can be easily obtained.

Further, since the upper surface of the cut is formed flat, the shape of the hot wire can be freely adopted, and packaging that matches the size and external shape of the packaged object is extremely easy.

Furthermore, even if there is a gap between the upper and lower wrapped films due to wrinkles, there is no risk of vacuum leakage because the cut portions of the film are heat welded.

[Brief explanation of the drawing]

Fig. 1 is a side view of the packaging machine, Fig. 2 is a sectional view of the chamber, Fig. 3 is a plan view and a front view of the cutting board, respectively.
A partially enlarged view, Figures 4A to 4E are explanatory diagrams of vacuum seal packaging, Figure 5 is an explanatory diagram of the state of cutting the film, and Figure 6 is a plan view of a cutting board according to a modified embodiment. - Heat insulation part 12...Support ring 13...There is a film roll. A... Packaging machine b... Item to be packaged a... Chamber f... Lower film g... Upper film h, hl, h2, h'... Heat wire 1... Upper chamber 2... ... Lower chamber 3 ... Packing 4.5 ... Vacuum pipe 6 ... Heating plate 6' ... Grip section 7 ... Cutting board 7' ... Upper surface of cutting board 8 ... Terminal 9... Lead wire 10... Terminal (a) (b) (c) (d) Fig.

Claims (2)

[Claims] (1) Place the item to be packaged via the lower film on a cutting board equipped with a film cutting means consisting of a hot wire, vacuum-tightly package the heat-softened upper film from above, and then energize the heating wire of the cutting board. A film cutting method for vacuum seal packaging that heat-melts and cuts the film. (2) A cutting board used in a film cutting method for vacuum tight packaging, which has a flat top surface and a hot wire attached to the top surface.