JP2007062770A - Egg pack package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an egg pack package which does not need an additional label from a packaging film, has a wide space describing commodity information, can prevent miscellaneous bacilli from sticking as an egg pack itself is not exposed, and has a high design nature capable of appealing to consumers. <P>SOLUTION: A polyolefin shrinkable film is made under a condition that flange parts each other of a main body and a lid body of the egg pack are piled up and carries a printing having the commodity information as well as the design nature. It is preferably drawn at least two-fold in one direction to have a heat shrinkable stress at 100°C of ≤0.50 N/cm so that the whole main body is overlapping shrink-packaged so as to make the printed face to be the outer face of the package. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an egg contained in a recyclable pack container such as polystyrene (hereinafter referred to as PSt) or polyethylene terephthalate (hereinafter referred to as PET), that is, an overlap packaging of an egg pack.

  Currently, eggs are sold in packs, ie egg packs. As a material of the egg pack, recyclable PSt or PET is mainly used, and sterilization is performed in advance to minimize contamination and adhesion of bacteria.

The pack has a substantially box shape that can be opened and closed with one side edge as a hinge, and a predetermined number of eggs are stably placed on the inside of the main body and the back surface of the lid according to the shape and size of the egg. An egg accommodating recess and a substantially truncated cone-shaped projection are provided so as to be accommodated.
Then, the lid is closed in a state where the eggs are accommodated in the egg accommodating recesses of the pack, and in general, the main body and the lid are stapled at the flange portion of the side edge opposite to the side edge serving as the hinge, It has been shipped.

Distributing them as egg packs resulted in new problems, although merits such as reduced egg damage during transportation were obtained.
One is that the pack body and lid are closed with staples, so it is cumbersome for consumers who have purchased the pack to open the pack. Risk of injury to fingers from staples left on the body.
Secondly, various product information including egg brand name (trademark), manufacturer, seller, place of origin, expiration date, storage method, bar code and other POS indications, egg size, optional design, etc. Displayed or printed merchandise labels are commonly used to convey to retailers, but egg packs are deformed according to the shape of the pack when stored in a container due to its unique shape, making it hard to see The problem arises. On the other hand, even when sticking to the outer surface of the pack, it is difficult to fix the pack because of the unique shape of the pack. Also, since the product label is made of paper or incinerated plastic material, it must be disposed of separately from recyclable materials such as PSt and PET, which are pack materials, and the product label is adhered to the pack. In this case, peeling is troublesome, and it is difficult to carry out separation disposal sufficiently.

In order to solve the above problem, shrink packaging is performed so that the flange portion of the main body and the lid body overlap each other in the egg pack, and the wrapping around the back surface of the main body from the back surface of the main body with a plastic material that can be incinerated. At the same time, it has been proposed to perform so-called sleeve packaging in which both side portions of the pack are partially opened, and to stick a product label made of a material that can be incinerated on the outer surface of the sleeve packaging (Patent Document 1).
However, in the method of attaching the product label, the space for writing the product information is limited by the size of the label, and the cost of the label is required. In addition, in the case of sleeve packaging having openings on both side portions, there is a concern about adhesion of germs from the openings.

Moreover, although the method of shrink-wrapping the whole container in which the egg was accommodated by the heat-shrinkable film is also reported, the container which accommodates an egg is a tray which has many recessed parts which do not have a cover body (patent document 2). ), A lid case is placed on the top of a tray having a special egg storage space (Patent Document 3), and the strength of the upper part of the package is insufficient or the container is expensive. was there. In addition, the heat-shrinkable film used is a transparent film, and there is no report of overshrink wrapping the whole egg pack using a printed film.
Actual No. 3089976 Japanese Utility Model Publication No. 51-66088 JP 2004-284651 A

  The present invention solves the above-described problems in the prior art, prevents adhesion of germs from the opening, provides product information without sticking a product label, and provides an egg pack package with excellent design. The issue is to provide.

As a result of intensive studies to solve the above problems, the present inventors have found that the problem can be solved by overlapping shrink shrink wrapping the whole with a printed low shrinkage polyolefin shrink film. The present invention has been completed.
That is, the present invention provides the following (1) and (2) egg pack packages.
(1) An egg pack in which the whole egg pack is overlap-shrink wrapped with a polyolefin-based shrink film that has been printed with the product information of the egg added to the design, along with the product information of the egg. Packaging body.
(2) A polyolefin-based shrink film is subjected to a corona discharge treatment on the surface of a film having a heat-shrinkage stress of 0.5 N / cm or less at 100 ° C. obtained by stretching a polyethylene-based resin at least twice in one direction. The egg pack package according to claim 1, wherein the corona-treated surface is printed, and is overlap shrink-wrapped so that the printed surface is an outer surface of the package.

  The package obtained in the present invention does not require a separate product label from the packaging film, and has a large space for describing product information, and the egg pack itself is not exposed, so that it is possible to prevent adhesion of germs and consumption. It is a package with high design that can appeal to consumers. Moreover, since the main body and the lid are not closed with staples, opening is easy, and there is no risk of injury to fingers.

Hereinafter, the egg pack package of the present invention will be described in detail.
The film used in the present invention is a polyolefin-based heat-shrinkable film, but a single-layer or multilayer film whose surface layer is a polyethylene-based resin is preferable. Examples of the polyethylene resin used for the surface layer include low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, and ethylene-4. -Ethylene such as methylpentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-decene-1 copolymer, and α-olefin having 4 to 10 carbon atoms Copolymers, and those having ethylene as an unsaturated compound such as conjugated or non-conjugated dienes, or acrylic acid, methacrylic acid, vinyl acetate or the like as a copolymerization component are also included. These polymers may be acid-modified, for example, polymers graft-modified with α, β-unsaturated carboxylic acid, alicyclic carboxylic acid, or derivatives thereof.
Among them, in consideration of obtaining sufficient adhesiveness as a polyethylene-based resin, the density and MFR (melt flow rate, 190 ° C., 2.16 kgf) specified in JIS K 6760 are 0.930 g / cm ³ or less, A linear low density polyethylene of 0.1 to 10 g / 10 min is preferred. More preferred is a linear low density polyethylene having a density of 0.900 to 0.925 g / cm ³ , and still more preferably a density of 0.905 to 0.920 g / cm ³ .

When a copolymer of ethylene and an α-olefin having 4 to 10 carbon atoms is used as the polyethylene resin, a density of 0.88 to 0.94 g / cm ³ , MFR is considered in consideration of obtaining appropriate tackiness. (190 degreeC, 2.16kgf) The thing of 0.1-5.0 g / 10min is preferable. The α-olefin content is preferably 1 to 30% by weight.
Further, when a copolymer of ethylene and acrylic acid, methacrylic acid, vinyl acetate or the like is used as the polyethylene resin, MFR (190 ° C., 2.16 kgf) 0 is considered in view of obtaining appropriate tackiness. Preferred are those having a comonomer content of 5 to 30% by weight.

In the case of a multilayer film, it may be a laminate by a combination of the above polyethylene resins, but depending on the application and purpose of the packaging film, the core layer and the intermediate layer are other than polyethylene resins, for example, polypropylene resins, Resins such as polyvinyl chloride, polyvinylidene chloride, polystyrene, polyester, ethylene-vinyl acetate copolymer, and ionomer resin may be used.
As for the thickness of a single layer or a multilayer film, 5-40 micrometers is common in the shrink-wrapping field | area, and 8-20 micrometers is more suitable. In addition, the layer configuration of the multilayer film may be set according to the packaging application and required characteristics. For example, in the case of a three-layer configuration, the thickness of the core layer is preferably set to 1 to 10 times the thickness of the surface layer. . In that case, the thickness of the surface layer needs to be at least 1 μm or more for stabilization of the seal at the time of packaging.

The film used in the present invention is manufactured by a well-known method, for example, a method combining a T-die method, an inflation method, a roll uniaxial stretching method, a tenter uniaxial stretching method, a tenter sequential or simultaneous biaxial stretching method, or a tubular It can be produced by a method such as simultaneous biaxial stretching. Hereinafter, an example of the manufacturing method of the multilayer film by the tubular simultaneous biaxial stretching method will be described.
First, the resin constituting each layer is melted and kneaded with separate extruders, and melted and extruded in a tube shape from a multilayer annular die is rapidly cooled with a refrigerant and folded to produce an original fabric. When extruding, plasticizer, antioxidant, surfactant, adhesive, antifogging agent, colorant, ultraviolet absorber, lubricant, inorganic filler as long as the characteristics of the present invention are not impaired on the surface layer or all layers. Etc. may be added. Moreover, you may irradiate radiation, such as an electron beam, after an original fabric preparation, and may perform a crosslinking process.
Next, the raw fabric is passed between two pairs of differential nip rolls and heated to about 60 to 130 ° C., and then air is introduced therein to form bubbles and continuously stretched while blowing cold air. The draw ratio is 2 times or more, preferably 3 times or more in the vertical and horizontal directions. If necessary, heat treatment is performed in a tensioned state or a relaxed state below the melting point of both surface layers, and wound as a master roll.

The film used in the present invention preferably has a heat shrinkage stress at 100 ° C. of 0.5 N / cm or less. When the heat shrinkage stress is high, a relatively soft egg pack may be deformed by the shrinkage stress during shrink wrapping, which is not preferable in terms of appearance.
The heat shrinkage stress can be made 0.5 N / cm or less by selecting the draw ratio and heat treatment conditions.

The film used in the present invention has been subjected to printing.
Prior to printing, it is desirable that the film has a surface state of a film having a wetting index exceeding 38 mN / m, preferably 40 mN / m, by corona discharge treatment. In general, the higher the wetting index, the better the ink adhesion, and a wetting index of 40 mN / m or more is preferable because more stable ink adhesion can be obtained.
As a method of performing the corona discharge treatment, for example, a corona discharge treatment facility may be introduced into a part of a slitter that cuts into an appropriate width and winding amount from a master roll, and the corona discharge treatment and cutting may be performed on the same line. Alternatively, a corona discharge treatment facility may be introduced into the film manufacturing process, and for example, the corona discharge treatment may be performed after the heat treatment.
As the corona discharge treatment conditions, the treatment current and inter-electrode spacing as factors of the treatment degree are appropriately adjusted so that the wetting index of the film exceeds 38 mN / m at 20 ° C., preferably 40 mN / m or more. So that the surface treatment. For example, a wetness index in the above range can be obtained by processing at a corona discharge dose of 20 to 100 W / m ² / min.

  As printing ink used for printing, generally used printing ink for plastic film can be used. For example, solvent- or water-based plastics containing polyamide resins, cellulose derivatives, polyurethane resins, maleic resins, acrylic resins, polyester resins, chlorinated olefin resins, maleated olefin resins, etc. as binder resins that characterize ink performance Film printing inks can be used.

The package of the present invention is obtained by accommodating eggs in an egg pack, overlapping the flange portions of the main body and the lid, and overlapping shrink-wrapping the entire egg pack with a polyolefin-based shrink film.
The egg pack used in the present invention is obtained by bulging and molding a synthetic resin sheet, and integrally forming the container body and the lid through the bent portion, depending on the shape and size of the egg inside the body and the back of the lid. An egg packaging container provided with an egg accommodating recess capable of accommodating a predetermined number of eggs in a stable state and a substantially truncated cone-shaped projection, and a known one can be used.
The egg pack containing the eggs is temporarily packaged with a polyolefin-based shrink film and then shrink-packed in a state where the flange portions of the main body and the lid are simply overlapped without being closed by a stapler or the like.
Specifically, shrink wrapping is performed using a manual wrapping machine or an automatic wrapping machine, and includes half-fold wrapping and pillow wrapping depending on the wrapping form. In both cases, the stretched film has air vent holes and is wrapped so that the printed surface is the outer surface of the package, and the packaged items are temporarily packaged in a bag shape by heat sealing, and inside the heated shrink tunnel The film is made to be a beautiful package in which the film is tightly shrunk with respect to the package.
A heat seal in the running direction called a center seal is selected from a knurled seal, a fusing seal, and an electrostatic seal, and a fusing seal method is generally selected for the center seal and the top and bottom seals in the vertical direction. However, it is not limited to these.
The film of the present invention needs to be printed with a design considering shrinkage, and the ink is more preferably heat resistant.
In addition, when the printing surface is the inner surface, it is desirable that the printing surface be the outer surface because the heat sealing property is lowered by the corona treatment for printing and the heat sealing property is inhibited by the printing ink itself. .

Hereinafter, the present invention will be described in more detail with reference to examples.
In the examples and comparative examples, the resins used are as follows.
LL1: Linear low density polyethylene having a density of 0.920 g / cm ³ and MFR (190 ° C., 2.16 kgf) of 1.0 g / 10 min. LL2: Density of 0.920 g / cm ³ , MFR (190 ° C., 2 .16 kgf) is a linear low density polyethylene LL3 of 0.5 g / 10 min. Ethylene-butene-1 having a density of 0.920 g / cm ³ and MFR (190 ° C., 2.16 kgf) of 0.5 g / 10 min Polymer EVA1: ethylene-vinyl acetate copolymer having a density of 0.933 g / cm ³ , MFR (190 ° C., 2.16 kgf) of 3.5 g / 10 min, and a vinyl acetate content of 15% by weight PP1: JIS K 6758 Propylene-ethylene copolymer having a density of 0.90 g / cm ³ , MFR (230 ° C., 2.16 kgf) of 4.0 g / 10 min ethylene content of 2% by weight Coalescence

  The heat shrinkage stress was measured by attaching the cut sample to a grip attached to the lower end of the strain gauge and immersing the sample in glycerin heated to 100 ° C. in a hollow beaker for 10 seconds.

  Printing was performed using DX-60 indigo (produced by Sakata Inx Co., Ltd.) and XGS-3200 (produced by Sakata Inx Co., Ltd.), which are printing inks for gravure surface printing.

Example 1
100% by weight of LL1 was melted and kneaded at 120 to 230 ° C. with one extruder and extruded from an annular die, and the tube-shaped molten resin was taken out while being cooled with water and folded to produce a raw fabric. Next, the raw material was passed through a low-speed nip roll, heated to about 100 ° C. to form bubbles with air inside the tube, cooled with cold air, folded, and taken up with a high-speed nip roll. At that time, the draw ratio was adjusted so that the speed ratio of the high-speed nip roll and the low-speed nip roll was 3 times in the machine direction and 3 times in the transverse direction from the ratio of the film width after stretching and the original fabric width. Next, after performing a tension heat treatment at 80 ° C., the film was opened in two and wound on a master roll. The stretched film obtained had a heat shrinkage stress of 0.31 N / cm at 100 ° C.
After about 1.5 hours, corona discharge treatment was performed at a corona discharge dose of 85 W / m ² / min. The wetting index after the corona discharge treatment was 42 mN / m.
Printing was performed at a speed of 100 m / min using DX-60 indigo for gravure surface printing and XGS-3200, and the evaluation of ink adhesion was also good.
With the printed film, wrap the egg pack containing eggs so that the printed surface becomes the outer surface of the package, wrap it in a tube shape with heat seal, and cut the front and back of the egg pack with fusing seal As a result of shrink wrapping by packaging in a bag shape and passing through a shrink tunnel, a tightly packed body was obtained and the printed design was also beautiful. In addition, the product information of eggs could be clearly identified.

Example 2
Same as Example 1 using 3 extruders and 3 layer annular die with composition of 80.0 wt% LL1 and 20 wt% LL3 for both surface layers and composition of 100 wt% LL2 for the core layer The original fabric was prepared, stretched 6 times in length and 6 times in width, heat treated, and wound up on a master roll. The film obtained had a heat shrinkage stress of 0.43 N / cm at 100 ° C.
After 0.5 hour, corona discharge treatment was performed at a corona discharge dose of 70 W / m ² / min. The wetting index after the corona discharge treatment was 42 mN / m.
Gravure printing was performed at a speed of 100 m / min, and the evaluation of ink adhesion was also good.
As a result of shrink-wrapping an egg pack containing eggs in the same manner as in Example 1 with the printed film, a tightly packed body was obtained and the printed design was also beautiful. In addition, the product information of eggs could be clearly identified.

Example 3
Both surfaces are made of 100% EVA 1 composition and the core layer is 100.0% PP1 composition using three extruders and a three-layer annular die. did. A corona discharge treatment is provided between the heat treatment and the master roll, and after stretching and heat treatment in the same manner as in Example 1 (100 ° C. heat shrinkage stress 0.34 N / cm), a corona discharge dose of 70 W / m ² / min. Was subjected to corona discharge treatment and wound up on a master roll. The wetting index of the film wound around the master roll after the corona discharge treatment was 43 mN / m.
Gravure printing was performed at a speed of 100 m / min, and the evaluation of ink adhesion was also good.
As a result of shrink-wrapping an egg pack containing eggs in the same manner as in Example 1 with the printed film, a tightly packed body was obtained and the printed design was also beautiful. In addition, the product information of eggs could be clearly identified.

Comparative Example 1
A stretched film was produced in the same manner as in Example 2, and the film having a heat shrinkage stress at 100 ° C. of 0.56 N / cm was obtained by changing the heat treatment conditions.
The obtained film was subjected to corona treatment and printing in the same manner as in Example 2. Then, when the egg pack containing the eggs was shrink-wrapped, the egg pack was deformed and the appearance was unsightly.

  As described above, the egg pack package of the present invention does not require a separate product label from the packaging film, and also has a large space for describing product information, and the egg pack itself is not exposed. It is a package with high design that can prevent adhesion and appeal to consumers.

Claims (2)

  An egg pack package in which the whole egg pack is overlap-shrink wrapped with a polyolefin-based shrink film that has been printed with the product information of the egg and design added to the design, along with the egg product information.   A corona discharge treatment is applied to the surface of a film in which a polyolefin-based shrink film is obtained by stretching a polyethylene-based resin at least twice in one direction and the heat shrinkage stress at 100 ° C. is 0.50 N / cm or less. The egg pack package according to claim 1, wherein the package is overlap shrink-wrapped so that the printed surface is the outer surface of the package.