JP4841084B2 - Shrink package and packaging method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shrink package and a shrink packaging method in which an object to be packaged such as food is covered with a heat-shrinkable film, and then the film is heat-shrinked and closely adhered to the object to be packaged.
[0002]
[Prior art]
In general, breads sold in supermarkets and convenience stores are manufactured and packaged in large quantities by the manufacturer and supplied to the dealers. Therefore, as a packaging form, a packaging body in which an object to be packaged such as bread is accommodated in a cylindrical transparent film and then open ends on both sides are sealed by heat sealing is generally used.
[0003]
However, in the case of the package, since the film is not in close contact with the package, the package moves due to vibration during transportation. There is no problem if the packaged goods are sweet breads such as buns. Appearance problems occur, such as spilling out of the side dish, or the inside of the film and the pan with the sauces used for the side dish. For this reason, it is necessary to wrap the cooking pan in such a manner that the film is closely attached to the cooking pan to some extent and the state where the prepared vegetables are sandwiched is maintained.
[0004]
Stretch packaging and shrink packaging can be used as a method for packaging a film in close contact with an object to be packaged.
[0005]
Stretch wrapping is a method of wrapping an object to be wrapped so that the film can be folded at least on the bottom surface of the object to be wrapped using a stretch film. Therefore, the stretch wrapping basically wraps the packaged object by stretching the film, so that an excessive tightening force is applied to the packaged object, and the packaged object is very soft and soft like a cooking pan. The bread and prepared dishes are crushed and the appearance is deteriorated, and the soft texture of the bread itself may be significantly reduced. Therefore, it is very difficult to finely adjust the tightening force by the machine, and automation is difficult.
[0006]
In stretch wrapping, the film is folded back to the bottom of the cooking pan and taped with an adhesive tape or the like, or heat-sealed on a hot plate, the folded portion irregularly overlaps the film, and looks bad. When opening, the film of the folded portion or the portion that is in close contact with the package is torn, making it difficult to open (low openability), and there is also a risk that the prepared dishes pop out with the momentum of breaking the film.
[0007]
On the other hand, shrink wrapping is a method in which a package is primarily packaged with a heat-shrinkable film, and then the film is heated and shrunk with hot air or the like to adhere to the package, and the process can be automated. It is a widely used packaging method. In this method, the tightening force to the package due to the shrinkage force of the film generated during heat shrinkage is determined by the packaging margin ratio in the pre-packaging body before heat shrinkage (the film margin relative to the maximum circumference of the package in a predetermined direction). It can be adjusted by changing the ratio of dimensions), and is a packaging method suitable for soft packages such as breads.
[0008]
However, the conventional shrink wrapping has a tubular shape, a bag shape, a heat-shrinkable film that is folded in half, etc., and the film is shrunk after the opening end is sealed by heat sealing, There was a problem that the film was in close contact with the entire packaged object, and it was difficult to open as with the stretch packaging. In particular, when the packaged item is very soft and soft like a cooking pan, the packaged item may be crushed when the film adhered to the packaged item is pulled and broken.
[0009]
Furthermore, in shrink wrapping, a number of deaeration holes are provided in the film in order to remove the air inside when the film is thermally contracted. Therefore, when food is directly packaged, there is a problem in the sanitary condition after packaging.
[0010]
As described above, there are various problems in the conventional packaging method in which a film is closely attached to an object to be packaged. Usually, packaging is performed manually. However, even with manual packaging, it is inevitable that a certain amount of tightening force is generated when a film is wound around an object to be packaged, and the packaging work efficiency is poor, so that it is not suitable for a large amount of packaging. Furthermore, the package by hand, like the stretch wrapping, has a problem that it is easy to open because the folded portion of the film is taped or heat-sealed, and there is a risk that the prepared dishes will pop out when opened.
[0011]
[Problems to be solved by the invention]
It is an object of the present invention to provide easy opening in shrink packaging that can be automated, and to prevent contamination of the packaged product after packaging. In particular, the packaged product is soft like a cooking pan. An object of the present invention is to provide a shrink package that can be easily opened without affecting the article to be packaged, and a shrink package that solves the sanitary problems after packaging, and a packaging method.
[0012]
[Means for Solving the Problems]
A first aspect of the present invention is a shrink wrapping body obtained by covering a cooking pan with a heat-shrinkable film, sealing the opening end, and then heat-shrinking the film, and the heat-shrinkage rate of the heat-shrinkable film Is at least 20% in the width direction at 80 to 160 ° C., and the heat shrinkage stress is 400 g / mm ² or less in both the vertical and horizontal directions at 80 to 160 ° C., and is subjected to a crosslinking treatment, A shrink wrapping body characterized by having a through hole penetrating two or more films in the vicinity of a seal portion and having a peripheral portion sealed and sealed.
[0013]
In the shrink package of the present invention includes sealed by a label affixed from the outside to the film, and this having one circular deaerating hole diameter 2~5mm a preferred embodiment.
[0014]
The second aspect of the present invention is cylindrical , at least 20% in the width direction at a heat shrinkage of 80 to 160 ° C., and 400 g in both the vertical and horizontal directions at a heat shrinkage stress of 80 to 160 ° C. / Mm ² or less, the cooking pan is housed in a heat-shrinkable film subjected to a crosslinking treatment, and at the same time as or after the opening end of the tubular film is sealed, two sheets in the vicinity of the sealing portion The above film is partially sealed, and at the same time, a cut is made in the sealing region to form a through hole whose peripheral edge is sealed, and the whole film is heated and thermally contracted to prepare a cooking pan . It is the shrink wrapping method characterized by making it closely_contact | adhere.
[0015]
In the shrink wrapping method of the present invention, pre-circular deaerating hole diameter 2~5mm keep one provided, sealing the dehydration pores by sticking a label after heat shrinkage of the film in the tubular film Is included as a preferred embodiment.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The shrink wrapping body of the present invention is characterized in that it has a through hole with a peripheral edge sealed in the vicinity of the seal part at the opening end, and the through hole becomes a knob part at the time of opening and can be easily opened. it can. Further, the through hole accommodates an article to be packaged in a cylindrical film and seals two or more films at the same time when the opening end is sealed or sealed, and at the same time within the sealing region. It can be easily formed by making a notch.
[0017]
Hereinafter, the shrink package and the packaging method of the present invention will be described in detail with reference to embodiments.
[0018]
FIG. 1 is a diagram showing the steps of an embodiment of the shrink wrapping method of the present invention. In the figure, 1 is an item to be packaged (cooking pan), 2 is a cylindrical film, 3 is a seal part, 4a and 4b are Open ends 5a and 5b are seal portions of the open ends 4a and 4b, 6 is a through hole, 7 is a seal portion at the periphery of the through hole 6, 8 is a package, 9 is a deaeration hole, and 10 is a label. Hereinafter, each process will be described.
[0019]
In this invention, as shown to Fig.1 (a), the to-be-packaged object 1 is first accommodated in the cylindrical film 2 which consists of a heat-shrinkable film. FIG. 1 (a) shows a conventional pillow wrapping method in which a sheet-like film is folded from both sides to seal the end portions and wrap the article 1 while forming a tubular film 2. However, the tubular film 2 may be, for example, a film formed by inflation molding or a film in which two films are stacked and sealed at a pair of opposing end portions (two seal portions 3). In addition, as shown to Fig.1 (a), it is preferable to arrange | position the seal | sticker part 3 to a side surface, when there are two bottoms or two places of the to-be packaged object 1 so that it may look good after packaging.
[0020]
The heat-shrinkable film used in the present invention preferably has a heat shrinkage of 20% or more at least in the width direction at 80 to 160 ° C. Here, the heat shrinkage rate means that a 100 mm square film sample is placed in an air oven type thermostatic bath set at a predetermined temperature, treated for 10 minutes in a state where it can be freely heat shrunk, and then longitudinally and laterally (width). This refers to the value expressed as a percentage of the value obtained by calculating the amount of heat shrinkage of the film in the direction and dividing by the dimension before shrinkage. Similarly, the heat shrinkage stress is, as a maximum value measured in accordance with ASTM D2838, preferably in the temperature range of 80 to 160 ° C., preferably 400 g / mm ² or less in both the longitudinal and lateral directions of the film, more preferably It is 300 g / mm ² or less, more preferably 250 g / mm ² or less, and desirably 200 g / mm ² or less.
[0021]
The resin constituting the heat-shrinkable film used in the present invention is not particularly limited as long as it is a thermoplastic resin. For example, high pressure method low density polyethylene, high density polyethylene, ethylene-α olefin copolymer (linear low High density polyethylene, ultra low density polyethylene, and other soft resins with a crystallinity of 30% or less by X-ray method, polymerized with Ziegler catalyst, and polymerized using a catalyst usually called single site catalyst Polypropylene resins (homopolymers and copolymers with at least one α-olefin such as ethylene and butene), polybutene resins (homopolymers and at least such as ethylene or propylene) Copolymer with one kind of α olefin, etc.), poly-4-methylpentene resin, crystalline 1,2-polybutadiene A soft polymer comprising an α-olefin copolymer different from the ethylene-α-olefin copolymer, an ethylene-vinyl acetate copolymer, an ethylene-aliphatic unsaturated carboxylic acid copolymer, an ethylene-aliphatic unsaturated Carboxylate ester copolymers, block copolymers of vinyl aromatic hydrocarbons and conjugated dienes, and derivatives such as those obtained by hydrogenating at least part of their double bonds, ethylene-vinyl alcohol copolymers, polyamide resins, Polyester resins, and modified polymers thereof (acid-modified, ionized, etc.) can be mentioned. Blend resins obtained by mixing one or two or more resins selected from these resins, or these resins as main components ( A blend resin in which a resin other than the above is mixed can be used.
[0022]
The heat-shrinkable film used in the present invention may be one that has been subjected to irradiation crosslinking treatment with ionizing radiation, preferably an electron beam, and the one subjected to irradiation crosslinking treatment is effective in terms of easy opening. Further, the heat-shrinkable film may be a single layer or a multilayer, and at least one layer has an antifogging agent, a plasticizer, an antioxidant, an ultraviolet absorber, a lubricant, a colorant, a surfactant, an antiblocking agent, Inorganic fillers, tackifiers, and the like can be included, and corona treatment, plasma treatment, and various coating treatments can be performed.
[0023]
Moreover, as a thickness of the heat-shrinkable film used in the present invention, a film having a thickness of 5 to 100 μm is usually used for shrink wrapping. From the viewpoint of resource saving and waste reduction, it is preferably 5 to 50 μm. Preferably it is 5-30 micrometers.
[0024]
In the present invention, the packaging margin ratio (ratio of the margin dimension of the film 2 to the maximum circumference of the article 1 in a predetermined direction) in a state where the article 1 is accommodated in the tubular film 2 is preferably, It is appropriately adjusted in the range of 0 to 30% in the longitudinal direction (L direction) of the article 1 and 3 to 25% in the width direction (direction perpendicular to the longitudinal direction, C direction). Desirably, it is 5 to 20% in the L direction and 5 to 20% in the C direction. If the circumference of the package 1 is the same in the L direction and the C direction, both are adjusted in the range of 0 to 20%. It is preferable to do.
[0025]
Next, as shown in FIG.1 (b), the opening ends 4a and 4b of the cylindrical film 2 are seal-sealed. In addition, in this embodiment, after storing the to-be-packaged object 1 in the cylindrical film 2 cut | disconnected by the predetermined length, although the process of sealingly sealing the opening ends 4a and 4b was shown, in an automatic shrink wrapping machine, Accommodates the package 1 while forming a long heat-shrinkable film into a cylindrical shape, and melts and seals the open ends 4a and 4b with a fusing blade (cuts the open ends 4a and 4b at the same time as heat-sealing. )In some cases.
[0026]
In the present invention, the through hole 6 is formed before the thermal contraction of the tubular film 2. The through-hole 6 penetrates through two or more films constituting the cylindrical film 2 (two sheets other than the seal part 3 and may be substantially three or more in the seal part 3), and the peripheral part is sealed. It is sealed. That is, the internal air does not escape from the through-hole 6 when the tubular film 2 is thermally contracted. FIG. 2 shows a cross-sectional view of the vicinity of the through hole 6 in FIG.
[0027]
The position of the through hole 6 is in the vicinity of one of the seal portions 5a and 5b of the opening ends 4a and 4b (5a in FIG. 1B), and the seal between the peripheral seal portion 7 of the through hole 6 and the opening end 3a. The part 5a may be in contact.
[0028]
Further, the through-hole 6 is easily formed simultaneously with the sealing of the open ends 4a and 4b, or after that, by partially sealing two or more films and at the same time making a cut in the sealing region. can do. Specifically, it can be preferably formed by bringing a hot blade, which is usually used for fusing sealing, into contact with the film. Therefore, in the case of the automatic shrink wrapping machine that cuts and seals the open ends 4a and 4b, a hot blade is attached in the vicinity of the fusing blade that cuts and seals the open end 4a. Thus, the through holes 6 can be formed simultaneously with the cutting and sealing of the open ends 4a and 4b.
[0029]
The size of the through-hole 6 according to the present invention is preferably 1/15 to 1/2 of the bag width of the tubular film 2 and more preferably 1/10 to 10 when a straight cut is made. 1/3.
[0030]
In the present invention, the sealing portions 3, 5a, 5b, and 7 can be sealed by fusing sealing, heat sealing, impulse sealing, ultrasonic sealing, or the like.
[0031]
Next, the opening ends 4a and 4b of the cylindrical film 2 are sealed and the cylindrical film 2 is thermally contracted by applying hot air, steam, etc. to the preliminary packaging body in which the through-hole 6 is formed, and the article to be packaged 1 The shrink wrapping body 8 of the present invention [FIG. 1 (c)] is obtained.
[0032]
At this time, since the peripheral edge of the through-hole 6 is sealed, the peripheral seal 7 protrudes from the package 8 as shown in FIG. It becomes a state. Therefore, when the package 8 is opened, the package 8 can be easily opened by pinching and pulling the protruding portion as a knob.
[0033]
In general, when performing shrink wrapping, a deaeration hole is formed in the film for extracting the air inside. Also in this invention, as shown to Fig.1 (a), (b), the deaeration hole 9 is previously formed in the cylindrical film 2, and this deaeration hole 9 is attached by sticking the label 10 after heat contraction. It can seal and can prevent the contamination of the package 1 after packaging. Although the number of deaeration holes 9 is not particularly limited, it is preferable that the number is smaller in consideration of an operation for applying the label 10, and is preferably one. Further, the size and shape of the deaeration holes 9 are preferably circular with a diameter of 2 to 5 mm. The label 10 may be a product label that displays a product name, date of manufacture, expiration date, price, and the like.
[0034]
Examples of a method for forming the deaeration hole 9 include formation of a melt hole by a laser or a hot needle, mechanical formation by a needle, or a method by punching. Therefore, the method of forming a melt hole is preferable.
[0035]
Examples of the automatic packaging machine and the semi-automatic packaging machine for carrying out the shrink packaging method of the present invention include an L-shaped packaging machine and a pillow packaging machine.
[0036]
【Example】
As a heat-shrinkable film, both surface layers are linear low density polyethylene (comonomer: hexene-1, density: 0.913 g / cm ³ ) 90% by weight and high pressure method low density polyethylene (density: 0.924 g / cm ³ ). It consists of 10% by weight of mixed resin, and the core layer is different from the above in the form of linear low density polyethylene (comonomer: hexene-1, density: 0.928 g / cm ³ ) 75% by weight and high pressure method low density polyethylene (density: 0). .924 g / cm ³ ) 3 layers composed of 25% by weight of mixed resin (thickness ratio of each layer = 15: 70: 15) having a thickness of 11 μm and subjected to crosslinking treatment were used. The degree of cross-linking treatment was expressed as a gel fraction, and a sample was extracted for 12 hours in boiling p-xylene, and the ratio of the insoluble portion was 21% by weight expressed by the following formula.
[0037]
Gel fraction (% by weight) = (sample weight after extraction / sample weight before extraction) × 100
[0038]
In addition, the heat shrinkage rate of the heat shrinkable film is 140% at a longitudinal direction of 83% and a transverse direction of 81%. The heat shrinkage stress at 120 ° C. is 190 g / mm ^{2 in} the longitudinal direction and 200 g in the transverse direction. / Mm ² .
[0039]
A cut roll was made in the lengthwise direction (L direction) of a roll bread having a length of 210 mm as an object to be packaged, and a cooked roll bread sandwiched with fried noodles was produced. The outer periphery (maximum) in the direction (C direction) orthogonal to the L direction of the cooking roll was 205 mm.
[0040]
The heat shrinkable film is provided with a deaeration hole having a diameter of about 3 mm with a hot needle, and then the cooking roll pan is wrapped while forming a seal part 3 by heat sealing in a pillow packaging method as shown in FIG. Furthermore, the open ends 5a and 5b were sealed with a fusing seal device to form a preliminary package. At this time, a thermal blade having a blade width of 15 mm is provided adjacent to the fusing blade that seals and seals one of the open ends 5a, and at the same time as the sealing of the open end 5a, the peripheral portion is sealed with a through hole. 6 was formed. The temperature of the fusing blade and the hot blade was 220 ° C.
[0041]
In the preliminary packaging body, the packaging margin for the cooking roll was 20% in the L direction and 18% in the C direction.
[0042]
The preliminary package is passed through a hot air tunnel with a length of 900 mm controlled at 140 ° C. and passed for 5 seconds to thermally shrink the heat-shrinkable film, and then a product label is attached to the deaeration holes to form the deaeration holes. Sealing was performed to obtain a shrink package.
[0043]
The resulting package has a film that is reasonably close to the cooking roll and does not move in the package, and because the roll and side dishes are not fastened by the film, the appearance is excellent, and a through hole is formed. Since the part protrudes from the package, the film can be easily peeled off by pinching and pulling, and the easy-opening property is excellent.
[0044]
【The invention's effect】
As described above, the shrink package of the present invention has a through-hole whose peripheral edge is sealed and sealed, so that it does not affect the package by pinching and pulling this part. Can be opened easily. The through-hole can be formed only by adding a simple configuration to a conventional automatic shrink wrapping machine. Furthermore, even if the film is provided with deaeration holes for venting air during heat shrinkage of the film, the deaeration holes are sealed by using a product label, etc., so that the packaged material can be easily contaminated after packaging. Can be prevented.
[0045]
Therefore, according to the present invention, easy opening is realized in shrink wrapping, and further, contamination of the packaged material after wrapping is prevented. Therefore, the use of shrink wrap is expanded, and the efficiency of wrapping is improved by automation in each use. Can be achieved. In particular, even when the packaged item is a soft body such as a cooking pan, it is possible to provide a package that is excellent in appearance, easy to open, and preferable in terms of hygiene.
[Brief description of the drawings]
FIG. 1 is a process diagram showing an embodiment of a shrink wrapping method of the present invention.
FIG. 2 is a cross-sectional view of the vicinity of a through hole in the preliminary package of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Package 2 Cylindrical film 3, 5a, 5b, 7 Seal part 4a, 4b Open end 6 Through-hole 8 Packaging body 9 Deaeration hole 10 Label

Claims (4)

A shrink wrapping body obtained by covering a cooking pan with a heat-shrinkable film and sealingly sealing the opening end, and then heat-shrinking the film, wherein the heat-shrinkable film has a heat shrinkage rate of at least 80 to 160 ° C. It is 20% or more in the width direction, and the heat shrinkage stress is 80 g / mm ² or less in the longitudinal direction and the transverse direction at 80 to 160 ° C., and is subjected to crosslinking treatment. A shrink package having a through-hole penetrating the above film and having a peripheral edge sealed and sealed. The shrink package of Claim 1 which has one circular deaeration hole with a diameter of 2-5 mm sealed by the label affixed on the said film from the outside. Cylindrical , heat shrinkage rate is at least 20% in the width direction at 80 to 160 ° C., and heat shrinkage stress is 80 g / mm ² or less in both the vertical and horizontal directions at 80 to 160 ° C. When the cooking pan is stored in the heat-shrinkable film and the opening end of the tubular film is sealed with seal, or after that, two or more films are partially sealed in the vicinity of the seal portion. At the same time, a cut is made in the sealing region to form a through hole whose peripheral edge is sealed, and the whole film is heated and thermally shrunk to adhere to the cooking pan. Method. The shrink wrapping method according to claim 3 , wherein one circular deaeration hole having a diameter of 2 to 5 mm is provided in advance in the tubular film, and the deaeration hole is sealed by applying a label after the film is thermally contracted.

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