JP2006335446A - Packaging material for syrup-containing fruit product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin-made packaging material for a syrup-containing fruit product by which a change in color and degradation in taste are effectively prevented, excellent preserving performance for contents is assured for a long time, and the contents can be directly viewed from the outside. <P>SOLUTION: The packaging material for the syrup-containing fruit product is formed by superposing a transparent laminated film, an oxygen absorbent layer, and an oxygen absorbent laminated film so that their heat seal layers face one another. The transparent laminated film includes an inorganic vapor deposition biaxial stretched polyester film, a biaxial stretched nylon film, and a heat seal layer. The oxygen absorbent layer includes an inorganic vapor deposition biaxial stretched polyester film, a biaxial stretched nylon film, a polyolefine film containing a titanium dioxide, and the composition of a polyolefine and ferrous oxygen absorbent. The oxygen absorbent laminated film includes a heat seal layer containing a titanium dioxide. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a packaging material for syrup-containing fruit products, and more particularly, to a packaging material for syrup-containing fruit products that can effectively prevent coloring of syrup-containing fruit and allows the contents to be visually observed from the outside.

Conventionally, metal cans, glass bottles, various plastic containers, and the like are used as packaging containers, but plastic containers are used for various applications in terms of light weight, impact resistance, and cost. However, in the case of metal cans and glass bottles, oxygen permeation through the container wall is zero, whereas in the case of plastic containers, oxygen permeation through the container wall occurs in an order that cannot be ignored. It is a problem.
In order to solve such a problem, a plastic container has a multi-layered container wall, and at least one of them is a resin having oxygen permeability such as a metal foil such as an aluminum foil or an ethylene-vinyl alcohol copolymer. Is being used.

On the other hand, in order to remove residual oxygen in the container and improve the storage stability of the contents as a packaging material excellent in the storage stability of the contents, the use of an oxygen absorbent has been performed for a long time. A packaging material in which a resin layer not containing an oxygen absorber is sandwiched between the inner and outer surfaces of a resin layer containing a system oxygen absorber has also been proposed (Patent Document 1).
Oxygen in the sealed container has an important influence on the storage stability and flavor retention of the contents of the container. Oxygen present from the beginning of sealing in the head space or the like in the sealed container reduces the flavor retention of the contents. This tendency is particularly prominent in packaged foods that are sterilized by retort for the purpose of improving the storage stability of the contents, and it is known to cause the destruction of pigments and the decrease in flavor retention.

JP-A-10-114371

  In syrup-containing fruit products, conventionally canned products were generally used, but because of the characteristics of the contents, it is desired that the contents can be seen through from the outside. Attempts have been made to fill a multi-layer plastic container, or a packaging material made of a laminate containing only an aluminum foil on one side. However, with these packaging materials, discoloration of the fruit product containing syrup occurred and could not be put to practical use.

  Accordingly, an object of the present invention is a plastic packaging material for fruit products containing syrup, in which discoloration and a decrease in flavor are effectively prevented, and the content is preserved for a long period of time. It is to provide a packaging material that is directly visible.

  According to the present invention, an inorganic vapor-deposited biaxially stretched polyester film, a biaxially stretched nylon film, a transparent laminated film comprising a heat seal layer, an inorganic vapor-deposited biaxially stretched polyester film, a biaxially stretched nylon film, a titanium dioxide-containing polyolefin film, An oxygen-absorbing layer composed of a composition of polyolefin and iron-based oxygen absorbent and an oxygen-absorbing laminated film composed of a titanium dioxide-containing heat-sealing layer are laminated so that the heat-sealing layers face each other. A packaging material for fruit products containing syrup is provided.

  In the packaging material for fruit products containing syrup of the present invention, the contents can be visually confirmed from the outside, and can be stored for a long time without causing discoloration or deterioration in flavor of the fruit products containing syrup. It becomes possible.

  As shown in FIG. 1, the packaging material for fruit products containing syrup according to the present invention comprises a transparent laminated film 1 composed of an inorganic vapor-deposited biaxially stretched polyester film 2, a biaxially stretched nylon film 3, and a heat seal layer 4, Oxygen absorbency comprising axially stretched polyester film 5, biaxially stretched nylon film 6, titanium dioxide-containing polyolefin film 7, oxygen-absorbing layer 8 comprising a composition of polyolefin and iron-based oxygen absorbent, and titanium dioxide-containing heat seal layer 9 It is an important feature that the laminated film 10 is superposed so that the heat seal layers face each other.

That is, in the present invention, the transparency of the packaging material is maintained by using a laminated film composed of the inorganic vapor-deposited biaxially stretched polyester film 2, the biaxially stretched nylon film 3, and the heat seal layer 4 as the transparent laminated film. It is possible to visually check the contents from the inside and to provide oxygen barrier properties that can effectively prevent oxygen permeation from the outside.
Further, the inorganic vapor-deposited layer is vulnerable to bending and protrusion, and pinholes and cracks are generated, and oxygen may permeate from the scratched portion. In the present invention, the inorganic vapor-deposited biaxially stretched polyester film 2 is inorganic vapor-deposited. By providing an impact-resistant layer made of a biaxially stretched nylon film 3 between the inorganic deposited biaxially stretched polyester film 2 and the heat seal layer 4 with the layers on the inside, the biaxially stretched polyester film on the outside, and inorganic deposition. The generation of pinholes and cracks in the layer is effectively prevented.

  On the other hand, as the oxygen-absorbing laminated film 10, an inorganic vapor-deposited biaxially stretched polyester film 5, a biaxially stretched nylon film 6, a titanium dioxide-containing polyolefin film 7, and an oxygen absorbing layer 8 comprising a composition of polyolefin and an iron-based oxygen absorbent. By using a laminated film composed of the titanium dioxide-containing heat seal layer 9, it is possible to effectively capture the residual oxygen in the packaging material and to provide oxygen barrier properties that can effectively prevent oxygen permeation from the outside. It becomes.

Also in the oxygen-absorbing laminated film, the impact resistance of the biaxially stretched nylon film 6 between the inorganic vapor-deposited biaxially stretched polyester film 5 and the oxygen-absorbing layer 8 with the inorganic vapor-deposited layer on the inside and the biaxially stretched polyester film on the outside. By providing the layer and the buffer layer of the polyolefin film 7, occurrence of pinholes and cracks in the inorganic vapor deposition layer is effectively prevented.
In addition, in the oxygen-absorbing laminated film, the presence of the oxygen-absorbing layer 8 can effectively capture residual oxygen in the packaging material, and prevent changes in the flavor and color tone of the fruit product containing syrup as the contents. The storage stability can be remarkably improved.

In addition, since the polyolefin film 7 adjacent to the oxygen absorbing layer and the heat seal layer 9 contain titanium dioxide, the color of the oxygen absorbing layer 8 in which an iron-based oxygen absorbent exists as a dispersed particle layer in the polyolefin continuous phase. Can be concealed.
Furthermore, sandwiching the oxygen absorbing layer 8 with the titanium dioxide-containing unstretched polyolefin film 7 and the titanium dioxide-containing heat seal layer 9 effectively prevents the iron-based oxygen absorbent particles in the oxygen absorbing layer from being exposed to the outer surface. In addition to suppressing the reduction in flavor due to iron exposure and iron migration from the packaging material production stage to the initial stage of packaging, the volume expansion associated with the unevenness formed on the surface by the dispersed particles of the iron-based oxygen absorbent or the oxygen absorption of the iron-based oxygen absorber Can be mitigated, and it is possible to suppress the occurrence of cracks and the decrease in interlayer adhesion. In addition, since the titanium dioxide-containing unstretched polyolefin film 7 and the titanium dioxide-containing heat seal layer 9 have high oxygen permeability and excellent moisture resistance, oxygen in the container permeates and transfers to the iron-based oxygen absorbent via the polyolefin. On the other hand, there is an advantage that direct contact between moisture and the iron-based oxygen absorbent is prevented. For this reason, in the packaging material of this invention, it becomes possible to perform oxygen absorption very efficiently at the time of a retort sterilization, and the preservation | save initial stage.

(Inorganic vapor-deposited biaxially stretched polyester film)
An inorganic vapor-deposited biaxially stretched polyester film is formed on the surface of a biaxially stretched polyester film substrate by chemical vapor deposition (CVD), vacuum vapor deposition, sputtering, ion plating, etc., and inorganic substances such as silicon oxide, alumina, etc. A ceramic, carbon or the like is vapor-deposited, and the thickness of the vapor-deposited layer is as thin as 50 to 1000 angstroms, but exhibits an excellent barrier property against oxygen. The thickness of the inorganic-deposited biaxially stretched polyester film is advantageously in the range of 5 to 50 μm, particularly 10 to 30 μm, from the viewpoint of handling.
Between the biaxially stretched polyester film and the inorganic vapor-deposited layer, a primer layer such as a mixture of a polyester urethane resin, a polyester resin, and a resin selected from an isocyanate resin, an epoxy resin, and a melamine resin is provided. In addition, as a surface coating layer on the inorganic vapor deposition layer, the following chemical formula (1)
M (OH) n (1)
(However, M is a metal element, R is an alkyl group having 1 to 8 carbon atoms, and n is an integer of 1 to 4)
You may provide the alkoxide coating-film layer represented by these.
Examples of the polyester film include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), or a blend thereof.

(Biaxially stretched nylon film)
Examples of the biaxially stretched nylon film include nylon 6, nylon 6,6, nylon 6 / 6,6 copolymer, nylon 10, nylon 12, or a blend thereof.
The thickness of the biaxially stretched nylon film layer should be in the range of 5 to 50 μm, particularly 10 to 25 μm. When this thickness is less than the above range, the protective effect on the inorganic vapor deposition layer is insufficient. On the other hand, when the thickness exceeds the above range, flexibility and flexibility as a packaging material tend to be reduced, and cost is increased. Is also disadvantageous.

(Oxygen absorption layer)
The oxygen-absorbing layer of the oxygen-absorbing laminated film is formed from a composition of polyolefin and an iron-based oxygen absorber. In the present invention, the iron-based oxygen absorbent particles are used in the form of a composition with polyolefin in order to make it possible to form the oxygen absorbent particles into a packaging material and to prevent their falling off.
The iron-based oxygen absorbent particles used in the oxygen absorbing layer may be a blend of reducing iron powder and an oxidation promoter or catalyst, but the core particles of the reducing iron powder and the oxidation accelerator coated thereon. It is more preferably composed of a catalyst layer. Further, the oxidation promoter or catalyst should be present in an amount of 0.1 to 10% by weight, particularly 0.1 to 5.0% by weight, per reducing iron powder.
As the oxygen absorber, all iron-based oxygen absorbers conventionally used for this type of application can be used. In addition to the above-described reducing iron, iron lower oxides such as ferrous oxide, iron trioxide, Further, a reducing iron compound, for example, a main component of one or a combination of iron carbide, silicon iron, iron carbonyl, iron hydroxide and the like can be used. The oxidation promoter or catalyst includes alkali metal, alkaline earth metal hydroxide, carbonate, sulfite, thiosulfate, tertiary phosphate, secondary phosphate, organic acid salt, halide, etc. Other examples include water-soluble organic compounds such as glucose and sodium polyacrylate.

The iron-based oxygen absorber has a median particle diameter of 10 to 50 microns as measured by a laser scattering method, and the aspect ratio (minor axis / major axis) of 0.75 or less accounts for 50% or more. Spindles or flat particles are preferred. Further, those having a BET specific surface area of 0.5 m ² / g or more and an apparent density of 2.2 g / cc or less are preferable.

  Examples of the polyolefin in which the iron-based oxygen absorber is dispersed include, for example, low-, medium-, or high-density polyethylene, linear low density polyethylene, isotactic polypropylene, syndiotactic polypropylene, linear low density polyethylene, ethylene- Propylene copolymer, polybutene-1, poly-4-methyl-1-pentene, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene-acetic acid Examples thereof include a vinyl copolymer, an ion-crosslinked olefin copolymer (ionomer), and an ethylene-acrylic acid ester copolymer. These can be used alone or in the form of a blend of two or more.

From the viewpoint of heat resistance against retort sterilization, crystalline propylene polymers are suitable. Under the condition that they are homopolypropylene or crystalline, propylene-based random copolymers and block copolymers are used. used. The propylene-based polymer used preferably has a melt flow rate (JIS K6758) of 0.8 to 12 g / 10 min.
In a more preferred embodiment, the propylene polymer and the ethylene polymer are mixed and used in a weight ratio of 100: 1 to 1: 1, particularly 50: 1 to 3: 2.
The thermoplastic resin in which the oxygen absorbent is dispersed is formed from a blend of a plurality of substantially incompatible thermoplastic resins or elastomers, and the incompatible thermoplastic resin or elastomer has a non-uniform distribution structure in the matrix, particularly Forming a multilayer distribution structure is also effective in preventing the iron oxide particles from protruding to the inner surface side or the outer surface side.

The polyolefin composition containing an iron-based oxygen absorbent may be prepared by dispersing 2 to 60 parts by weight of an iron-based oxygen absorbent per 100 parts by weight of the polyolefin. If the amount of the iron-based oxygen absorbent is below the above range, oxygen absorption On the other hand, when the amount of the iron-based oxygen absorbent exceeds the above range, the moldability of the blended composition is lowered, or the above-described troubles due to volume expansion after oxygen absorption are likely to occur.
The thickness of the oxygen absorbent-containing resin layer should be in the range of 10 to 100 μm, particularly 15 to 60 μm. If this thickness is less than the above range, the oxygen absorption capacity tends to be insufficient, while if the thickness is more than the above range, moldability tends to deteriorate and flexibility and flexibility as a packaging material tend to decrease.

(Titanium dioxide-containing polyolefin film)
The titanium dioxide-containing polyolefin film used for the oxygen-absorbing laminated film is, for example, low-, medium- or high-density polyethylene, linear low density polyethylene, isotactic polypropylene, syndiotactic polypropylene, linear low density polyethylene, Such as ethylene-propylene copolymer, polybutene-1, poly-4-methyl-1-pentene, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, etc. It can be formed from a polyolefin containing titanium dioxide. In terms of interlayer adhesion with the oxygen absorbing layer, it is desirable that the polyolefin film and the polyolefin of the oxygen absorbing layer are the same type. The polyolefin film is blended with titanium dioxide for the purpose of concealing the coloring caused by the oxygen absorber, and the blending amount is not particularly limited, but a range of 5 to 25 parts by weight per 100 parts by weight of the polyolefin is appropriate.

  The thickness of the polyolefin film should be in the range of 5 to 50 μm, especially 10 to 30 μm. When this thickness is less than the above range, iron oxide particles produced by oxidation tend to protrude and the flavor tends to decrease. On the other hand, when the thickness exceeds the above range, oxygen absorptivity tends to decrease.

(Titanium dioxide-containing heat seal layer)
The titanium dioxide-containing heat seal layer used on the inner surface side of the oxygen-absorbing laminated film can be the same as the above-mentioned titanium dioxide-containing polyolefin film, and titanium dioxide is a polyolefin in order to conceal the coloring of the oxygen-absorbing layer. It is preferably blended in the range of 5 to 25 parts by weight per 100 parts by weight. The thickness is preferably 5 to 50 μm, particularly preferably 10 to 30 μm.

(Heat seal layer)
The heat seal layer used on the inner surface side of the transparent laminated film can use the same polyolefin as that used for the titanium dioxide-containing heat seal layer described above, and in particular, from the viewpoint of heat sealability, the same type is used. It is preferable to do. The thickness is preferably in the range of 30 to 200 μm, particularly 50 to 100 μm.

(Laminate)
The transparent laminated film used for the packaging material in the present invention can be prepared by a conventionally known method such as a dry lamination method or a sandwich lamination method.
In the case of dry lamination, the biaxially stretched nylon film 4 and the heat seal layer 5 are sequentially laminated on the vapor-deposited surface of the inorganic vapor-deposited biaxial polyester film 2 by the dry lamination method to obtain a transparent laminated film 1 Create

On the other hand, the oxygen-absorbing laminated film is prepared by first laminating a biaxially stretched nylon film 6 and a titanium dioxide-containing polyolefin film 7 sequentially on the vapor deposition surface of the inorganic vapor-deposited biaxial polyester film 5 by a dry lamination method. .
Next, the titanium dioxide-containing polyolefin film 7 of the pre-laminated body and the separately prepared titanium dioxide-containing heat seal layer 9 are opposed to each other, and an iron-based oxygen absorbent-containing polyolefin composition is extruded therebetween to absorb oxygen by a sandwich lamination method. A laminated film is produced. In the sandwich lamination method, specifically, an extruder and a die lip are arranged between two lamination rolls, two layers supported by each lamination roll are supplied between the rolls, and the molten resin is extruded between these layers. The laminated body is formed at the nip position between the rolls.

In addition, it is preferable from the point of adhesiveness to improve the wettability of the film to be used by corona discharge treatment etc.
Adhesive resins used in the dry lamination method include isocyanate or epoxy thermosetting adhesive resins, carboxylic acids, carboxylic anhydrides, carboxylates, carboxylic acid amides, carboxylic acid esters, etc. on the main chain or side. A thermoplastic resin containing a concentration of 1 to 700 milliquivalent (meq) / 100 g resin, particularly 10 to 500 meq / 100 g resin can be used in the chain.
Suitable examples of the thermoplastic adhesive resin include ethylene-acrylic acid copolymer, ion-crosslinked olefin copolymer, maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, acrylic acid grafted polyolefin, ethylene-vinyl acetate copolymer. , One or a combination of two or more of copolyester, copolyamide and the like.

(Use)
The packaging material for fruit products containing syrup according to the present invention comprises the above-mentioned transparent laminated film and oxygen-absorbing laminated film so that the heat seal layers face each other, and ordinary pouches with three- or four-sided seals, pouches with gussets It can take the form of standing pouches, pillow packaging bags and the like. In addition, when shape | molding to a standing pouch, it is preferable to form a bottom part with an oxygen absorptive laminated film.
The syrup-containing fruit product to be filled in the packaging material of the present invention is, for example, various fruits such as yellow peach, mandarin orange, pineapple, etc. soaked in syrup, and after being filled with nitrogen in the packaging material of the present invention, Although it is subjected to retort sterilization, flavor and hue can be well maintained over a long period of time by filling the packaging material of the present invention.

Example 1
As a transparent laminated film, a laminated film composed of an inorganic vapor-deposited biaxially stretched polyethylene terephthalate film (12 μm) / biaxially stretched nylon film (15 μm) / linear low density polyethylene film (80 μm) is used as an adhesive by a dry lamination method. It was created using an adhesive.
On the other hand, as the oxygen-absorbing laminated film, inorganic vapor-deposited biaxially stretched polyethylene terephthalate film (12 μm) / biaxially stretched nylon film (15 μm) / linear low density polyethylene film (20 μm) / linear low density polyethylene containing titanium dioxide (20 μm) / Laminated film composed of oxygen absorbing layer (50 μm) / titanium dioxide-containing linear low density polyethylene (30 μm). First, biaxially stretched nylon film and titanium dioxide-containing polyolefin film are sequentially dried on the vapor-deposited surface of inorganic vapor-deposited biaxial polyester film. Lamination is performed to prepare a preform, and then the titanium dioxide-containing polyolefin film of this pre-laminate and a separately created titanium dioxide-containing heat seal layer are opposed to each other, and an iron-based oxygen absorbent-containing polyolefin is interposed therebetween. set Things were created extruded by a sandwich lamination method.
The titanium dioxide content is 15% by weight for the titanium dioxide-containing polyolefin film in the preform, and 30% by weight for the titanium dioxide-containing heat seal layer, and the oxygen-absorbing layer is an iron-based oxygen absorbent. Was made from a resin composition blended in an amount of 10% by weight in an 80:20 (weight ratio) blend of a propylene polymer and an ethylene polymer.

The transparent laminated film and the oxygen-absorbing laminated film were overlapped so that the heat seal layers were opposed to each other, and the periphery was heat sealed to produce a 220 cm × 290 cm pouch-shaped packaging material. The oxygen absorption capacity of this pouch was 0.086 cc / cm ² .
This pouch is filled with yellow peach, tangerine, pineapple mixed fruit, sterilized at 90 ° C for 45 minutes, and then stored at 35 ° C. After 8 months, discoloration and changes in flavor are not observed. There wasn't.

(Example 2)
The pouch prepared in Example 1 was filled with a mixed fruit consisting of tangerines and pineapples, sterilized at 83 ° C. for 45 minutes, and then stored at 35 ° C. The discoloration and flavor of the contents even after 8 months had passed. There was no change.

It is a figure which shows the cross-section of the packaging material of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent laminated film 2 Inorganic vapor-deposited biaxially stretched polyester film 3 Biaxially stretched nylon film 4 Heat seal layer 5 Inorganic vapor-deposited biaxially stretched polyester film 6 Biaxially stretched nylon film 7 Titanium dioxide-containing polyolefin film 8 Oxygen absorbing layer 9 Titanium dioxide-containing Heat seal layer 10 Oxygen-absorbing laminated film

Claims (1)

  Transparent laminated film consisting of inorganic vapor-deposited biaxially stretched polyester film, biaxially stretched nylon film, heat seal layer, inorganic vapor-deposited biaxially stretched polyester film, biaxially stretched nylon film, polyolefin film containing titanium dioxide, polyolefin and iron-based oxygen absorption Packaging for syrup-containing fruit products, characterized in that an oxygen-absorbing laminated film comprising an oxygen-absorbing layer composed of a composition with an agent and a titanium dioxide-containing heat-sealing layer is laminated so that the heat-sealing layers face each other Wood.

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