JP3213553B2 - Heat shrink wrapping method that does not require spike holes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to dustproof, moistureproof,
The present invention relates to a heat-shrinkable film excellent in insect repellency and a heat-shrinkable packaging method, and particularly to a heat-shrinkable film that does not require a spike hole and a packaging method using the same. More specifically, the present invention relates to a heat shrink wrapping method which is capable of completely closing an object to be wrapped and is suitable for food packaging such as snack noodles such as cup men and cup baked buckwheat.

[0002]

2. Description of the Related Art Conventionally, so-called heat shrink wrapping is economical in that an object to be wrapped is covered and sealed with a heat shrinkable film, and then the film is heat shrunk by a method such as passing through a heat shrink tunnel or blowing hot air. It is widely used because of its excellent workability and high speed.

[0003] When the object to be packaged is entirely packaged with such a heat-shrinkable film, usually, a small hole for degassing the air inside the film entirely covered with the heat-shrinkable film is provided on the film surface. A means of shrink wrapping after opening a plurality of pieces is adopted.

[0004]

When shrink-wrapping is performed using a heat-shrinkable film having a plurality of holes formed in the film surface, a spike hole having a diameter of 1 to 2 mm is usually formed by a needle. . However, when a hole is formed in the surface of the film as described above, the dustproof and moistureproof effects are reduced. Moreover, since there are many small holes on the surface of the package, the appearance of the package deteriorates.

[0005] Conventionally, as a method of shrink-wrapping without the need for spike holes, for example, a method of providing a gap in an overlapped portion of the edge of a heat-shrinkable film so that air inside can be exhausted (Japanese Patent Publication No. 56-1981). No. 10248), a method in which a seal is formed intermittently and the seal portions are arranged so as to overlap each other when viewed from a direction perpendicular to the length direction of the overlapped portion of the end portions (see Japanese Patent Application Laid-Open No. 4-31261). ), A method of providing a continuous seal portion at the outer end of the overlapped edge portion, providing a discontinuous seal portion at the inner end, and providing an air vent hole between the continuous seal and the discontinuous seal 87957), and a method of point-sealing the seal portions in a staggered manner (see JP-A-6-286732).

[0006] However, the product packaged by such a conventional method, particularly when used for packaging of food or the like, is not completely sealed, so that the product to be packaged is not allowed to pass through the opening, which is a gap between the seals. There is a problem in that the odor leaks and the leaked odor attracts the pests to cause the insects to collect, thereby causing the pests to enter the inside of the package through the hole.

Accordingly, an object of the present invention is to solve these drawbacks and to provide a heat-shrinkable film which does not require a spike hole and a packaging method which can completely seal an article to be packaged using the film.

[0008]

Means for Solving the Problems In order to achieve the above object, the heat shrink wrapping film of the present invention is prepared by applying a heat seal coating agent to at least one side edge of one side of the heat shrink wrapping film. A heat shrink wrapping film comprising the formed part coat layer.
As the film, a biaxially stretched polypropylene heat-shrinkable film is preferably used.

[0009] The part coat layer is provided on both side edges on one side of the film or on one side edge thereof, and the thickness thereof is appropriately determined in consideration of the type of the selected coating agent and the appearance after packaging. However, it is desirable to make the thickness as thin as possible, and is usually set to 0.5 μm to 2.0 μm. When the part coat layer is thick, the ear becomes high when the film is wound up. Also, when sealing from above the coated surface during heat sealing, heat is insufficient due to the thickness of the coating agent, which causes a decrease in sealing strength and the generation of pinholes.

[0010] The coating agent is a thermoplastic adhesive selected from vinyl chloride, vinyl acetate copolymer (EVA), acrylic resin, nitrocellulose, chlorinated PP, PVDC, hot melt, or the like. In the part coat layer to be formed, the film is melt-bonded at the temperature at the time of heat shrinkage in the subsequent step, and the film can be completely bonded and sealed.

The heat-shrinkable packaging method of the present invention uses a heat-shrinkable film provided with a part coat layer formed by applying a heat-sealing coating agent on at least one side edge of one side of the heat-shrinkable packaging film. I do. The film is wrapped around the object to be packaged while being continuously formed into a tube, and in this state, both side edges of the film are overlapped, and a portion which is close to the part coat layer and inner than the part coat layer by a rotary heat sealer. Alternatively, the inside including the part coat layer is heat-sealed (center-sealed).
At the time of heat sealing (center sealing), the present invention relates to a method in which a center seal portion is thermally bonded so as to form a stripe shape, and then a top sealer is used to melt the front and back of the film tube, and the package sealed at both ends is film-heated by a heating device. Is heated and shrunk, and the air inside the package is deaerated at the non-seal portion of the center seal.

The stripe width of the center seal portion is as follows.
A non-seal portion is formed between the seal portions with a depth of about 0 cm to 3.0 cm, and degassing is performed in the non-seal portion.

The deaeration holes formed by the non-sealing portions cause the coating agent of the part coat layer to be melt-bonded by heating during heat shrinkage in a shrink furnace, so that the film is completely sealed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

EXAMPLE 95.0% by weight of propylene and 5.0% by weight
Random propylene copolymer 10 with ethylene
A film forming raw material comprising 0 parts by weight and 0.45 parts by weight of silica as a blocking inhibitor was melted at 180 to 230 ° C. and extruded from a tubular die to form a diameter of 50 cm and a thickness of 2
A tube-shaped raw film of 50 μm was obtained.

This raw film is stretched 4.5 times in length and 4.5 times in width at 100 to 150 ° C. to have a thickness of 12 μm.
Was obtained.

On both sides of one side of the above-mentioned film A having a film width of 490 mm, a vinyl acetate-based heat sealing coating agent was applied with a width of 10 mm to form a part coat layer 10 to obtain a film B (see FIG. 1).

Next, using a film B, a seal width of 2 cm,
The center seal and both ends are sealed at a seal bar temperature of 250 ° C., and a side pillow package of cup-baked buckwheat is obtained to obtain a package sample C. That is, the packaged material 2 is wrapped in a tube while being formed into a tube by overlapping the both side edges of the film B with the bag making foamer 1 so as to form a joint, and in this state, the heat sealer 3 wraps the part coat layer on the part coat layer. A part that is close to and inside the part coat layer,
Alternatively, the inside including the part coat layer is heat-bonded (center-sealed) so that the center seal portion has a stripe shape (see FIG. 2). At the time of center sealing, for example, a rotary heat sealer 3 as illustrated in FIG. 3 is used. After the both side edges of the film B are overlapped and heat-sealed in this way, the front and rear of the film tube are blown by the fusing sealer 4 and the package sealed at both ends is sent to the shrink furnace 5 at a temperature of about 150 ° C. Then, the film B was heated and shrunk, and the air inside the package was degassed at the unsealed portion of the center seal. After degassing, the coating agent of the part coat layer was melt-bonded by heating during heat shrinkage in a shrink furnace, and the film was completely sealed.

As described above, the heat sealer used for the center seal is not limited to the helical gear type sealer as shown in FIG. FIG. 4 shows a seal pattern of the center seal portion. As shown in the drawing, there are several seal patterns shown as vertical stripes or diagonal stripes. The heat sealer having such a seal pattern is appropriately determined in consideration of the strength of the film and the like. FIG. 5 is a back view of the packaging sample C after shrink wrapping. In the figure, reference numeral 11 denotes a stripe-shaped center seal portion, and reference numeral 12 denotes a non-seal portion. Reference numeral 13 denotes a part coat seal portion, and FIG. 5 shows an example in which the part coat seal portion and the center seal portion are close to each other but do not overlap.
Indicates a case where the part coat seal portion and the center seal portion overlap each other. In FIG. 5, reference numeral 14 denotes a fusing seal portion.

Using the packaging sample C shown in FIG. 5, the amount of moisture absorbed into the contents was measured by storing it in a constant-temperature constant-humidity bath at a temperature of 40 ° C. and a humidity of 90% RH, and it was 4.2% / 10 days. When a penetration test was performed on the contents using the larvae of Nosyme moth, the number of larvae invaded was (0) / 3 days.

[0020]

COMPARATIVE EXAMPLE Using a film A, a plurality of conventional small holes were made in the film surface, and then a horizontal pillow package of cup fried noodles was obtained by shrink-wrapping, whereby a packaging sample D was obtained.

Using the packaging sample D, the amount of moisture absorbed into the contents was stored in a constant-temperature constant-humidity bath at a temperature of 40 ° C. and a relative humidity of 90%, and was measured to be 5.9% / 10 days. In addition, a penetration test into the contents was performed using the larva of Nosyme moth, and the number of larvae invading was 9/3 days.

Table 1 shows the results of moisture absorption and insect repellency when cup baked buckwheat was wrapped in a horizontal pillow using the heat-shrinkable polypropylene resin films of the above Examples and Comparative Examples.

[0023]

[Table 1]

[0024]

According to the heat shrinkable film of the present invention which does not require a spike hole and its packaging method, the package can be completely sealed. As a result, it is particularly effective in dustproofness, moistureproofness and insectproofness.

Furthermore, the method according to the invention can be used with only minor modifications of existing packaging machines.

[Brief description of the drawings]

FIG. 1 is a perspective view of a heat-shrinkable film according to the present invention.

FIG. 2 is a schematic view showing an example of a packaging method using the heat-shrinkable film according to the present invention.

FIG. 3 is a schematic view showing an example of a rotary center scillar used in the present invention.

FIG. 4 is a schematic view showing a seal pattern of a center seal portion.

FIG. 5 is an explanatory view showing a packaging form of the present invention.

[Explanation of symbols]

 B Heat Shrinkable Film of the Present Invention 1 Bag-making Homer 2 Packaged Material 3 Center Sealer 4 Top Sealer 5 Shrink Furnace 11 Center Seal 12 Non-Seal 13 Part Coat Seal 14 Fusing Seal

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Sakai 65, Hirayama, Asagu, Kosai-cho, Koga-gun, Shiga Prefecture Inside the Shiga Mill of Honshu Paper Co., Ltd. (56) References JP-A-63-197642 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B65B 53/00 B65B 51/10 B65D 71/08

Claims (1)

(57) [Claims] At least one side edge of one side of a film for heat shrink wrapping is provided with a part coat layer formed by applying a coating agent for heat sealing, and while the film is being continuously formed into a tube shape, an article to be packaged is provided. When wrapping the two side edge portions of the film in that state, the inner part of the part coat layer, or the inner part including the part coat layer close to the part coat layer and centered with a heat sealer, Non-seal on seal
After heat bonding so as to leave a part, the front and back of the tubular film are blown off by a fusing sealer, the film of the package sealed at both ends is heated and shrunk by a heating device, and the air inside the package at the unsealed part of the center seal. degassing carried out, after degassing, heat shrink wrapping method which does not require the spike hole, characterized in that part coating layer is sealed is melted adhesion.