JP2006103752A - Shrink packaging body and shrink-packaging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packaging body with excellent appearance after heat shrinkage and capable of improving in reduction of pinhole generation in shrink-packaging of a container with contents stored irrespective of a shape of the contents such as food or the container, and its packaging method. <P>SOLUTION: A tubular film formed by a longitudinal seal 4 made of a heat-shrinkable film 1 is heat-shrunk to come into tight contact with an object to be packaged. A shrink packaging body has a gusset-formed hermetic seal 3 with at least one of both ends of the tubular film folded inward from a side face. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  For example, the present invention wraps an object to be packaged such as a container including a food containing itself or a tray containing contents such as food with a heat-shrinkable film, and then heat-shrinks the heat-shrinkable film into the object to be packaged. The present invention relates to a closely packed package and a packaging method thereof.

  In general, for packaging of fresh foods and processed foods sold at supermarkets and convenience stores, etc., shrink packaging in which a tight finish and excellent cosmetics are utilized and wrapped with a heat shrinkable film is widely known. . For example, the shrink wrapping includes a tray containing contents and a heat shrinkable film, and the opening is hermetically sealed to form a pre-packaging body. The film is heat-shrinked while venting air from the deaeration holes provided thereafter, and is brought into close contact with the contents and the tray. In this shrink wrapping, when the vertical seal and the front and rear two sides are mainly sealed at the bottom of the pre-packed body (pillow wrapping method), the film is folded in half and the three sides that are the openings are sealed ( (Half-fold film system), two films are stacked and sealed on four sides (upper and lower film system), and the like. All of these methods are unsuitable as food packaging that dislikes the invasion of germs and the like because the film is provided with holes for deaeration in order to exclude air inside the package during heat shrinkage. Patent Document 1 is disclosed as a packaging method in which no hole for deaeration is provided.

This method uses a heat-shrinkable biaxially stretched plastic film with specified heat shrinkage rate and tensile recovery after heat shrink, wraps the tray containing the contents, degasses the interior, and opens the opening. After sealing and forming a preform having a hermetic seal portion on the side of the tray, the plastic film on the lower surface of the tray of the preform is heat-shrinked to attract the side hermetic seal portion downward, This is a packaging method in which the plastic film on the tray upper surface side is thermally shrunk.
In this method, since there is no hole for deaeration, it is easy to maintain hygienic conditions when packaging food, the side sealing seal does not move up to the upper surface of the package, and the appearance deteriorates due to pressing marks. Because it is difficult to occur, high merchantability and display effect are exhibited.

  On the other hand, in order to meet consumer needs such as food safety, security, and deliciousness, food additives, especially foods that do not use preservatives, have increased, and packaging methods to ensure safe and freshness have become even more important. It is coming. Among these, gas replacement packaging can maintain the freshness of food for a long period of time, and is frequently used as an effective packaging method that complements the effects of the above preservatives. Patent Document 2 is disclosed as a packaging method capable of gas replacement, and a tray containing contents is wrapped with a heat shrinkable multilayer film including a barrier resin layer and a heat sealable resin layer by a pillow packaging machine. The packaging method includes heat sealing the film at the bottom and the edge of the tray. According to this method, there is a description that a tray package that has excellent airtightness and can be stored for a long period of time is obtained, and that the shelf life of food is greatly improved when the inside of the package is replaced with gas.

However, in any of the packaging methods described in Patent Document 1 and Patent Document 2, the package obtained after heat shrinkage is more particularly in the case of a rounded or rounded container having a large curvature at the corner. The higher the film thickness, the more the film is not shrunk at the corners, and the film remains in a projecting shape (hereinafter referred to as a projecting product), resulting in a problem that the appearance is impaired. In addition, when a film with a certain degree of shrinkage is used, the hermetic seal part of the opening and the heat seal part at the edge of the tray shrink at the stage of heat sealing, and the edge part (ridge part) of the tray Since wrinkles or wrinkles are generated in the film, it tends to remain as wrinkles in a package obtained by heat-shrinking the film. Furthermore, there is a problem that another adjacent package body is damaged at the tip of the protrusion, or that the protrusion itself generates a pinhole due to repeated bending such as during transportation.
JP-A-9-99908 JP-A-4-327153

  An object of the present invention is to provide a packaging body and a packaging method thereof that are excellent in appearance after heat shrinkage regardless of the contents of food or the like or the shape of a container, and can greatly improve the occurrence of pinholes.

That is, the present invention is as follows.
1. A shrink wrapping body formed by using a heat shrinkable film, wherein the tubular heat shrinkable film is thermally shrunk to adhere to an object to be packaged, and at least one of both ends of the tubular film is from the side. A shrink wrapping body having a gusset-shaped hermetic seal part folded inside.
2. 1. The hermetic seal portion is located below. The shrink wrap body described in 1.
3. 1. The heat-shrinkable film has a gas barrier property. Or 2. The shrink wrap body described in 1.
4). An article to be packaged is stored in a tubular film made of a heat-shrinkable film, and one opening of the tubular film is hermetically sealed with a fold inward from the side, and the other opening is then opened. Similarly, a shrink wrapping method is provided, wherein a folding portion is provided, the inside is deaerated, the opening is hermetically sealed to form a gusset-shaped preliminary wrapping body, and then the heat shrinkable film is heat shrunk.
5. After forming the gusset-shaped pre-packaging body, the heat-shrinkable film on the lower surface side of the pre-packaging body is heat-shrinked, and the sealing seal part of the opening is drawn downward, and then the heat-shrinkability on the upper surface side of the pre-packaging body 3. The film is heat-shrinked. The shrink wrapping method according to claim 1.
6). 3. The heat shrink rate of the heat-shrinkable film is 10% or more in the horizontal direction and 20% or more in the vertical direction. Or 5. The shrink wrapping method according to claim 1.
7). 3. The heat shrinkable film has a gas barrier property. ~ 6. The shrink wrapping method according to any one of the above.
8). 3. The lateral dimension of the hermetically sealed portion of the gusset-shaped preliminary packaging body is equal to or less than the maximum projected lateral dimension as viewed from the upper surface of the packaged article. ~ 7. The shrink wrapping method according to any one of the above.

  The most different point of the present invention from the prior art is that a gusset-shaped fold is provided in the hermetic seal portion at the stage of the pre-packaging body before the heat shrinkage. Protrusions are less likely to occur, so the resulting package has a beautiful appearance, and pinholes are generated in the adjacent package caused by the tips of the protrusions, or pinholes are caused by repeated bending of the protrusions. The damage is greatly improved. In particular, among heat-shrinkable films having gas barrier properties, films with a polyamide-based resin layer arranged to enhance pinhole resistance are generally low in heat-shrinkability, but these films have poor heat-shrinkability. Can be packaged beautifully without protrusions, and it is extremely effective to greatly improve the wrinkles at the edges (ridges) of trays that have been generated in the past when using a film with a large degree of shrinkage. Packages and packaging methods can be provided.

  A preferred packaging body of the present invention and a preferred packaging method for obtaining the packaging body of the present invention will be described with reference to FIGS. 1 to 3 show a case of a conventional packaging method using a corner cutting tray. FIG. 1 shows a corner cutting tray 2 containing contents (the contents are omitted in the figure. Hereinafter, similarly) The contents are omitted in all the drawings.) Is stored in a cylindrical film formed by the vertical seal 4 made of the heat-shrinkable film 1, and this is degassed and the opening is hermetically sealed. It is a package. FIG. 2 is a plan view of this. FIG. 3 is obtained by first shrinking the film on the lower side of the tray of this pre-packed body and drawing the sealing seal part 3 of the opening downward, and then heating the whole with hot air to shrink the film on the upper side. Shrinkage package. Protrusions 5 are generated in the shrink wrapping body, and there are problems that the cosmetic appearance as a product is impaired in appearance, and that another wrapping body adjacent to the protrusions is damaged. It was.

  Next, the preferable form of this invention is demonstrated. 4 to 6 show an example of the packaging method according to the present invention using the same corner cutting tray and heat-shrinkable film as described above. FIG. 4 shows a case in which a corner tray 2 containing contents is contained in a cylindrical film formed by a vertical seal 4 made of a heat-shrinkable film 1, and both openings of the cylindrical film are inward from the side surfaces thereof. It is a preliminary packaging body having a gusset portion 6 that is evacuated and hermetically sealed while providing a folding portion. The folded portion is not necessarily provided on both side surfaces, and may be provided only on one side surface. In the case of both side surfaces, a difference may be provided in the degree of the left and right folded portions. FIG. 5 is a plan view of this. Here, the vertical seal has a palm-pasting method in which the inner surfaces of the heat-shrinkable film end portions are opposed to each other, or an envelope-pasting method in which the heat-shrinkable film end portions are stacked and the inner surface and the outer surface are fused, The film may be selected as appropriate in consideration of the heat seal characteristics of both surface layers of the film, but a palm-pasting method is preferred from the viewpoint of sealing integrity.

The hermetic seal of the present invention, including the vertical seal, is based on heat seal, but heat sealers include hot plate sealers, impulse sealers, ultrasonic sealers, band sealers, hot air sealers, high frequency sealers, frame sealers, etc. Just choose. The internal deaeration is performed before all the openings are hermetically sealed, and is intended to prevent the package from being swollen by the internal gas when the film is thermally contracted. is there. Then, by performing this deaeration, a packaging body in which the film is in close contact with the package body can be obtained without providing the deaeration holes used in the conventional shrink wrapping.
As a degassing method, just before forming the final hermetic seal portion, for example, a method of pressing a packaged object with a flexible material such as a sponge to extrude an internal gas, and a peripheral such as suction by a vacuum pump There is a method of deaeration using the pressure difference between the two, but it may be selected as appropriate.

FIG. 6 shows the present invention obtained by first shrinking the film on the lower side of the tray of the pre-packed body and then drawing the sealing seal 3 on the opening downward, and then shrinking the film on the upper side. This is a shrink-wrap package. As a means for heat shrinking, hot air is preferable, but hot water, heating steam, infrared rays, or the like can be appropriately used. Moreover, although shrinking of the film on the upper surface side may be performed by heating only from above the tray, it may be performed by applying hot air or the like from all directions. Here, the film on the lower surface of the tray is first thermally contracted, and the purpose of attracting the hermetic seal portion 3 of the opening downward is that when the film on the upper surface side of the tray to be subsequently contracted is thermally contracted, This is to prevent the appearance of the sheet from rising to the upper surface of the package. Therefore, when the film on the lower surface of the tray of the preliminary package is first thermally shrunk, this means that the hermetic seal portion is not located on the upper surface of the package. And most of the hermetic seal part in the shrink-wrapped body finally obtained by shrinking the film on the upper surface side of the tray to be performed next, preferably 80% or more of the lateral dimension of the hermetic seal part, more preferably 90%. % Or more, more preferably all of the lateral dimensions are located on the side or bottom of the final package. In the obtained shrink package, the protrusions 5 produced by the conventional packaging method are not seen, and the product has a favorable merchandise in terms of appearance, and to the adjacent package that the tip of the conventional protrusions 5 has brought about Damages such as pinholes are greatly improved.
Similarly, FIG. 7 to FIG. 9 show examples of the shrink wrapping method and the shrink wrap body of the present invention when a bowl-shaped container is used, and FIG. The example of the shrink wrapping body of this invention obtained by carrying out the heat shrink of the body is shown.

  In the method of the present invention, when forming a pre-packaging body having a gusset portion 6 by sealing and sealing both openings of the tubular film in a state where a fold portion is provided inward from the side surface, for example, FIG. 5, The lateral dimension Ls of the hermetically sealed portion of the preliminary packaging body having the gusset shape shown in FIG. 8 is preferably not more than the maximum projected lateral dimension Li as viewed from the top surface of the package, more preferably Ls / Li Is 0.9 or less. The measurement of Li is carried out by placing the object to be packaged in contact with each plate surface on a corner forming body composed of three flat plates having a right angle relative to the object to be packaged. A simple method is to measure the distance between two angulation bodies by sandwiching the object to be packaged with another angulation body. The hermetic seal portion tends to bend slightly due to heat shrinkage of the film. The linear distance at both ends of the hermetic seal portion is measured and this is defined as Ls.

As a result, the package finally obtained after heat shrinkage uses a film with poor heat shrinkability, or even if the deaeration just before sealing the opening is slightly insufficient, the hermetic seal part becomes a problem. The corner or tip of the container does not protrude beyond the side of the container parallel to the vertical seal, and it is more reliable to improve the adverse effects on adjacent packaging and to suppress wrinkles at the edge (ridge) of the tray. It will be a thing.
Next, the container referred to in the present invention includes a tray or a container composed of a lid and a main body, and also includes a container having a hinge and a main body called a food pack integrated. Furthermore, the above may have an inner pan located inside the tray or between the lid and the main body. When the container is used for gas replacement packaging, an opening is provided in a state in which the lid or the main body or the lid and the main body are fitted so that gas replacement can be easily performed, particularly in the case of a container with a lid. Ordinarily, it may be formed into a shape that can accommodate a small bag type oxygen scavenger. The material of these containers is not particularly limited, but is used alone or in combination from known resins, metals, paper, wood (including pulp), etc., but from the viewpoint of transparency and variety of shapes. Known resins are preferred because of their excellent moldability.

The heat-shrinkable film used in the present invention preferably has a heat shrinkage rate of 10% or more in the horizontal direction and 20% or more in the vertical direction. If the heat shrinkage rate in the lateral direction is 10% or more, the film and the packaged material after heat shrinkage are sufficiently adhered, and the film is less likely to be damaged or wrinkled. On the other hand, if the heat shrinkage rate in the vertical direction is 20% or more, the hermetic seal portion at the open ends is less likely to cause irregular shrinkage depending on the degree of folding for forming the gusset. More preferably, the heat shrinkage rate is 15% or more in the horizontal direction and 25% or more in the vertical direction, more preferably 20% or more in the horizontal direction and 25% or more in the vertical direction, and most preferably 20% or more in the horizontal direction. And the vertical direction is 30% or more. Although there is no restriction | limiting in particular about the upper limit of a heat contraction rate, in order to avoid the container deformation | transformation at the time of heat contraction, it is preferable that both the heat contraction rate of a horizontal direction and a vertical direction is 90% or less.
The heat shrinkage rate in the present invention refers to a 100 mm square film sample placed in an air oven type thermostat set at a predetermined temperature, treated for 10 minutes in a state where it can be freely heat shrunk, and then laterally and longitudinally. The heat shrinkage dimension is determined and expressed as a percentage of the value divided by the original dimension. The heat shrink temperature may be measured at an arbitrary temperature between 80 ° C. and 160 ° C. in consideration of the heat shrink temperature conditions during actual packaging.

  The resin constituting the heat-shrinkable film is not particularly limited as long as it contains a thermoplastic resin that can be heat-sealed. For example, high-pressure method low-density polyethylene, high-density polyethylene, ethylene-α olefin copolymer ( Linear low-density polyethylene, ultra-low-density polyethylene, and soft resins having a crystallinity of 30% or less by the X-ray method other than those described on the left), cyclic polyolefins, polypropylene-based resins (homo and comonomers such as ethylene and butene) A copolymer with a kind of α-olefin), poly-4-methylpentene resin, crystalline 1,2 polybutadiene, a soft polymer comprising an α-olefin copolymer different from the ethylene-α-olefin copolymer, ethylene-acetic acid Vinyl copolymer, ethylene-aliphatic unsaturated carboxylic acid copolymer, ethylene-aliphatic unsaturated carbon Bonic acid ester copolymers, block copolymers of vinyl aromatic hydrocarbons and conjugated dienes, derivatives such as those obtained by hydrogenating at least part of their double bonds, styrenic elastomers other than those on the left, ethylene-vinyl alcohol Copolymer (hereinafter referred to as EVOH), polyamide resin, polyester resin, biodegradable resin (polylactic acid, polycaprolactone, polybutylene succinate, polybutylene succinate adipate, polybutylene succinate terephthalate, polytetra Methylene adipate terephthalate, polybutylene adipate terephthalate, and the like), and modified polymers thereof (acid-modified, ionized, etc.), and a blend resin or a mixture of two or more resins selected from these Mainly using these resins (5 A blended resin in which a resin other than the above is mixed can be used.

The heat-shrinkable film used in the present invention may be a single layer or a multilayer, but in order to obtain further stability of the hermetic seal portion, it is preferably a multilayer film having a heat seal layer, and the layer structure may be symmetrical. It may be asymmetric. The thickness of the heat-shrinkable film is not particularly limited, but is preferably 5 to 100 μm, more preferably 10 to 80 μm, and still more preferably 10 to 50 μm.
In addition, what is necessary is just to select suitably resin used for a heat seal layer from the resin quoted above.
In addition, the heat-shrinkable film used in the present invention may be subjected to a crosslinking treatment, such as an antifogging agent, a lubricant, a plasticizer, an antioxidant, an ultraviolet absorber, an oxygen absorber, an antibacterial agent, a colorant, and various surfactants. An agent, an antiblocking agent, an inorganic filler, a tackifier, and the like can be included, and corona treatment, plasma treatment, and various coating treatments can be performed. Moreover, what was laminated | stacked variously with another kind of film may be sufficient as needed.

The most preferred form according to the present invention is the case where a heat-shrinkable film having gas barrier properties is used, and since many gas barrier films usually have poor heat-shrinkability, the packaging method of the present invention is particularly useful. It is. When the heat-shrinkable film of the present invention is a gas barrier film, the barrier property is preferably 30,000 ml / (m ² · day · Mpa) or less in terms of oxygen permeability at 23 ° C. and 65% RH. , more preferably ^{20,000ml / (m 2 · day ·} Mpa) or less, more preferably ^{10,000ml / (m 2 · day ·} Mpa) or less, more preferably ^{5000ml / (m 2 · day ·} Mpa) below is there. In addition, oxygen permeability is measured by the method of ASTM-D-3985.

As the gas barrier layer, a resin layer containing at least one of EVOH, polyamide resin, thermoplastic polyester resin, vinylidene chloride resin, polyacrylonitrile resin, polyglycolic acid resin, etc., vinylidene chloride resin, It may include a coating layer made of polyvinyl alcohol, EVOH, acrylic resin, and those obtained by dispersing an inorganic filler in these resins. Furthermore, in the case of packaging contents that dislike oxygen, a multilayer structure in which an oxygen absorbing layer is arranged is preferable.
In the present invention, the heat-shrinkable film having gas barrier properties is preferably used for gas replacement packaging, and the gas used includes nitrogen, oxygen, carbon dioxide, argon, xenon, krypton, alcohols, allyl mustard oil, and the like. They are used alone or in combination depending on the purpose. As a gas replacement method, a gas flash method is generally used, but for the purpose of improving the gas replacement rate, it is also possible to perform gas replacement by combining a pressure reduction treatment with an appropriate vacuum degree and a gas flash.

Example 1
Layer structure is ethylene-α olefin copolymer / adhesive resin / polyamide resin / amorphous polyester / EVOH / adhesive resin / ethylene-α olefin copolymer (inner heat seal layer), thickness ratio of each layer Packaging was performed using a film having a (%) of 10/5/20/20/10/5/30 and a thickness of 25 μm. Each of the ethylene-α-olefin copolymer layers contains 2 wt% of an antifogging agent mainly composed of a nonionic surfactant with respect to each layer, and the oxygen permeability of the film is 150 ml / (m ² · day · Mpa), the heat shrinkage at 120 ° C. was 28% vertical and 24% horizontal.
As a package, a container with a lid containing about 100 g of clay as a dummy was used as the contents. The container with a lid has an outer dimension of 130 mm (length) x 110 mm (width) x 38 mm (height) (height of the container body is 21 mm), and a gas replacement hole is attached to the lid. Each corner has a rounded shape with a radius of curvature of 38 mm and an arc length of 53 mm. The container is made of polystyrene and the body is made of polypropylene filled with an inorganic filler.

  Packaging was continuously performed at a rate of 30 packs per minute in a pillow shrink packaging machine capable of gas replacement by a gas flash system. Push the gusset fold-in bar in the cylindrical film that has been replaced with the atmosphere of nitrogen / carbon dioxide = 70/30 (volume ratio) by gas flush, and place the cylindrical film in the immediate vicinity of the end sealer. In the state where the folding part is provided inside the cylindrical film, the front is hermetically sealed first, then the cylindrical film moves forward, and similarly, the cylindrical inner part starts from the other opening end where the folding part is provided. After removing the excess gas with a sponge and degassing, the open end was hermetically sealed to form a pre-packed body having a gusset shape continuously. At this time, the value of Ls / Li was 0.73.

These preliminary packaging bodies were continuously blown with hot air from the bottom to shrink the film on the bottom and side surfaces of the container, and then further heated with air from the top of the preliminary packaging body to obtain a tightly finished packaging body. The obtained package had a clean appearance with no film protrusions remaining in the corners of the container, and no wrinkles on the container lid and the fitting flange portion of the main body.
In addition, 4 pieces of the resulting packaging are stacked in 2 stages, a total of 8 boxes are packed in cardboard, and after applying vibration in accordance with the JIS Z0232 packaging cargo-vibration test method, packaging is performed. The body was taken out and the presence or absence of a pinhole was investigated by "Ageless seal check" manufactured by Mitsubishi Gas Chemical Co., Ltd. The vibration test conditions were carried out with a cardboard box fixed, acceleration of 0.75 G, frequency of 5 to 50 Hz, 40 minutes in the vertical direction, 20 minutes in the horizontal and horizontal directions, and 20 minutes in the horizontal and vertical directions for a total of 80 minutes.
As a result, no pinhole was observed in the package.

(Comparative Example 1)
A shrink-wrap package was obtained in the same manner as in Example 1 except that the same film as in Example 1 was used for packaging without forming a folded portion inside the tubular film. At this time, Ls / Li of the preliminary package was 1.09. The resulting package had clear protrusions at the corners, was inferior in beauty, and the tip of one protrusion was hard and sharp. When this package was subjected to a vibration test in the same manner as in Example 1 and the occurrence of pinholes was examined, 3 out of 8 packages had pinholes that were thought to be due to the tip of the protrusion. Admitted.

(Example 2)
Example 1 except that the ethylene-α-olefin copolymer layer on the side opposite to the inner surface heat seal layer is crosslinked with an electron beam, and the thermal shrinkage at 120 ° C. is 35% vertical and 33% horizontal. Using a heat shrinkable film, packaging was performed under the same conditions as in Example 2. The oxygen permeability of this film was 140 ml / (m ² · day · Mpa).
Moreover, Ls / Li of the preliminary package was packaged under a condition of 0.71. The gel fraction of the cross-linked ethylene-α olefin copolymer layer was 41 wt%, while the gel fraction of the ethylene-α olefin copolymer layer of the inner surface heat seal layer was 0%.
The resulting package has a tight finish, as in Example 1 and Example 2, has no film protrusions at the corners of the container, and is almost free of wrinkles at the flanges of the container. Had a good appearance. Also, in the same pinhole resistance survey, no pinholes were found in the package.
The degree of crosslinking of the ethylene-α-olefin copolymer layer and the inner surface heat seal layer subjected to electron beam irradiation crosslinking is measured by heat-shrinking the entire film at a temperature of 160 ° C. or higher, and then measuring each layer only on the outer side. 50 mg within the thickness range from the surface to 90% is cut out and sealed in a wire mesh, and after treatment in boiling paraxylene for 12 hours by a method according to ASTM D2765, it is dried and weighed to the original weight of the sample. The weight ratio after the treatment was calculated and used as the gel fraction.

(Example 3)
The layer structure is ethylene-vinyl acetate copolymer / ethylene-α olefin copolymer / polypropylene resin / ethylene-α olefin copolymer / ethylene-vinyl acetate copolymer, and the thickness ratio (%) of each layer is 10 / 25/30/25/10, and packaging was performed using a film having a thickness of 11 μm. Each layer of the ethylene-vinyl acetate copolymer and the ethylene-α-olefin copolymer layer contained 1 wt% of an antifogging agent mainly composed of a nonionic surfactant with respect to each layer. The oxygen permeability of this film was 150,000 ml / (m ² · day · Mpa), the thermal shrinkage at 100 ° C. was 50% vertical and 34% horizontal. The Ls / Li of the preliminary package in this packaging was 0.82. The resulting package had no film protrusions at the corners of the container, had a tight and beautiful finish, and was excellent in merchantability.

  The present invention can be suitably used in the field of shrink packaging such as food packaging.

The perspective view which shows the preliminary | backup packaging body before heat shrink after completion of the sealing seal | sticker by the conventional packaging method using a corner cutting tray. The top view of the preliminary packaging body shown in FIG. The top view of the package obtained by carrying out the heat shrink of the preliminary package shown in FIG. The perspective view which shows the example of the preliminary packing body of the gusset shape of this invention which uses a corner cutting tray. FIG. 5 is a plan view of the preliminary package shown in FIG. 4. The top view of the package obtained by carrying out the heat shrink of the preliminary package shown in FIG. The perspective view which shows the example of the preliminary packing body of the gusset shape of this invention which uses a bowl-shaped container. The top view of the preliminary packaging body shown in FIG. The top view of the package obtained by carrying out the heat shrink of the preliminary package shown in FIG. The perspective view which shows the example of the package of this invention obtained by carrying out the heat shrink of the preliminary packaging body which used the container with a lid as a to-be packaged object.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film 2 Tray or container main body 3 Opening part sealing seal part 4 Heat seal part (vertical seal) for forming a cylindrical film
5 Protruding object 6 Gusset part 7 Lid Li Projected maximum dimension Ls seen from the top surface of the packaged object Horizontal dimension of the sealing seal part of the pre-package

Claims (8)

  A shrink wrapping body formed by using a heat shrinkable film, wherein the tubular heat shrinkable film is thermally shrunk to adhere to an object to be packaged, and at least one of both ends of the tubular film is from the side. A shrink wrapping body having a gusset-shaped hermetic seal part folded inside.   The shrink-wrap package according to claim 1, wherein the hermetically sealed portion is located below.   The shrink-wrap package according to claim 1 or 2, wherein the heat-shrinkable film has a gas barrier property.   An article to be packaged is stored in a tubular film made of a heat-shrinkable film, and one opening of the tubular film is hermetically sealed with a fold inward from the side, and the other opening is then opened. Similarly, a shrink wrapping method is provided, wherein a folding portion is provided, the inside is deaerated, the opening is hermetically sealed to form a gusset-shaped preliminary wrapping body, and then the heat shrinkable film is heat shrunk.   After forming a gusset-shaped pre-packaging body, the heat-shrinkable film on the lower surface side of the pre-packaging body is then heat-shrinked, and the hermetic seal portion of the opening is drawn downward, and then the heat shrinkability on the upper surface side of the pre-packaging body The shrink wrapping method according to claim 4, wherein the film is thermally shrunk.   The shrink wrapping method according to claim 4 or 5, wherein the heat shrink rate of the heat shrinkable film is 10% or more in the horizontal direction and 20% or more in the vertical direction.   The shrink-wrapping method according to any one of claims 4 to 6, wherein the heat-shrinkable film has gas barrier properties.   The shrink wrapping method according to any one of claims 4 to 7, wherein a lateral dimension of the hermetically sealed portion of the gusset-shaped preliminary packaging body is equal to or less than a maximum projected lateral dimension as viewed from the upper surface of the article to be packaged.

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