JPH11157029A - Composite sheet and enclosed container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite sheet and an enclosed container excellent in storage properties and sealing properties, which do not impair flavors intrinsic to various foods as contents. SOLUTION: This composite sheet has a flavor retaining layer 1 made of a three components copolymer resin having a saturated polyester resin, a polycarbonate resin, a mixed resin of the saturated polyester resin and the polycarbonate resin or of a bisphenol A, a diphenyl carbonate and a 1, 10-decane dicarboxylic acid as their constituent units, an oxygen absorbent layer 2 made of an oxygen-absorbing resin composition blended with a deoxidizer composition, a gas-barrier layer 3 made of a polyamide resin, 90 mol.% or more of diamine unit of which is a methaxylirene diamine unit and a supporting layer 4 made of a polyolefin resin. Further, a container is formed out of this composite sheet under the condition that the supporting layer 4 takes the outermost layer of the container and is sealed with a lid having gas-barrier properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a composite sheet and a sealed container. More specifically, the present invention provides
The present invention relates to a composite sheet and a sealed container having heat resistance, fragrance retention, and low-temperature impact resistance, and capable of high-temperature sterilization and suitable for filling foods and beverages.

[0002]

2. Description of the Related Art Conventionally, a plastic food container has a gas barrier layer made of an ethylene vinyl alcohol copolymer, a vinylidene chloride copolymer or the like, and a polyolefin layer such as polypropylene or polyethylene laminated on both sides thereof. Composite sheets of the configuration have been used. These composite sheets have been used heavily as having both gas barrier properties and sealing properties with the lid. However, as the research on the deterioration of the contents progresses, in the container having the polyolefin in the innermost layer, the innermost layer adsorbs the flavor of the contents, or the odor component of the innermost resin layer is transferred to the contents, Alternatively, it has been found that the contents are deteriorated by oxygen gas remaining in the container, and various means for improving the contents have been studied. For example, 5-8
No. 127 discloses a container capable of accommodating food without losing the flavor of food having high sensitivity to oxygen gas, as a fragrance retaining resin layer made of a saturated polyester resin or a polycarbonate resin, and a water vapor barrier resin layer. And a food container comprising a synthetic resin laminate in which a gas barrier resin layer and a thermoplastic resin layer are sequentially laminated. Japanese Patent Application Laid-Open No. 60-68938 discloses a package having a synthetic resin layer made of a saturated polyester resin or a polycarbonate resin and an oxygen gas barrier property as a package that can be packaged and accommodated without impairing the flavor of food highly sensitive to oxygen gas. There has been proposed a synthetic resin package having a multilayer structure composed of a synthetic resin layer. In addition, Japanese Unexamined Patent Publication
No. 244 discloses a food container capable of maintaining the aroma retaining property without the fragrance of alcoholic beverage or soft drink being adsorbed on the inner surface of the container, providing a polyester resin layer on the inner surface, A food container provided with a barrier layer having a polypropylene layer and an ethylene vinyl alcohol copolymer layer or a polyvinylidene chloride layer has been proposed. Further, Japanese Patent Publication No. 55-13907 discloses a multi-layer packaging material comprising a mixed resin layer composed of an ethylene vinyl alcohol copolymer and an ionomer and a polycarbonate resin layer as a packaging material having high storage stability and excellent hygiene. Has been proposed. Each of these containers is provided with a gas barrier layer to prevent oxygen gas from entering from outside the container,
The purpose is to prevent the contents from being altered by oxygen gas. However, when filling food containers with contents,
In many cases, a small space exists in a container, and oxygen gas contained in air in the space stays in the container and gradually deteriorates and degrades the contents. Also, when the contents are filled so that there is no space in the container, the contents before filling are in equilibrium with the atmosphere, and about 10 ppm of oxygen gas is usually dissolved in the contents. Oxygen gas dissolved in the contents also gradually alters and deteriorates the contents. For this reason, when filling and sealing a food container, an attempt has been made to remove oxygen gas present in the container in a gaseous state or dissolved in the contents. For example, Japanese Patent Application Laid-Open No. Sho 57-146651 proposes an oxygen scavenger for food packaging containers that is passive when dry and becomes oxyphilic when wet. JP-A 2-7
No. 2851 discloses, as a film-shaped oxygen absorber for preventing spoilage, deterioration and deterioration of food, containing an oxygen absorber composition obtained by stretching a thermoplastic resin film in which an oxygen absorber composition is dispersed in a film. Microporous films have been proposed.
Japanese Patent Application Laid-Open No. 4-90848 discloses a sheet and a packaging container with a small decrease in oxygen absorption rate, which are molded from a thermoplastic resin in which an oxygen absorbent comprising iron powder and a metal halide is dispersed and supported. Sheets and packaging containers have been proposed. Japanese Patent Publication No. 4-60826 discloses a plastic multilayer container having excellent oxygen permeability under conditions where moisture and heat act on a resin composition in which a gas barrier thermoplastic resin is mixed with an oxygen absorber. A container has been proposed in which a layer is provided and a layer of a moisture-resistant thermoplastic resin is provided on both sides thereof. Japanese Patent Application Laid-Open No. 7-309323 discloses an ethylene vinyl alcohol copolymer between an inner layer and an outer layer made of a polypropylene-based resin as a multi-layered molded container which is free from unevenness in thickness and has excellent appearance characteristics without color unevenness on the inner surface. There has been proposed a container provided with a layer composed of a polypropylene resin and a layer composed of an iron-based oxygen scavenger. Further, JP-A-8-7294
No. 1 discloses a multilayer structure having a three-layer structure of a gas barrier layer, a deoxygenating layer, and a gas-permeable layer as a multilayer structure capable of positively and efficiently absorbing oxygen without special treatment such as heat treatment. Has been proposed. JP-A-9-23990
No. 9 discloses a multilayer plastic container which is excellent in oxygen barrier properties and oxygen absorption, prevents the contents from adsorbing to the inner wall of the flavor, and prevents the color such as pigment from transferring to the inner wall. A multilayer plastic container composed of a laminate composed of a layer composed of a thermoplastic resin composed of ester repeating units, an olefin resin layer, a resin composition layer in which an oxygen absorbent is blended with a gas barrier resin and an olefin resin layer is proposed. Have been. Although these oxygen-absorbing materials have their own characteristics in terms of oxygen-absorbing ability, sealed containers for filling foods have an external appearance, moldability into a container shape, and flavor components of the contents due to the container inner surface material. No absorption of odor, no odor etc. from the inner material of the container to the contents, mechanical strength, especially impact resistance at low temperature, heat resistance to high temperature sterilization, sealing property with lid, sealed Since many properties such as the peelability of the lid are required, it has all of these properties,
There were no satisfactory sealed containers for filling food.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a composite sheet and a sealed container which do not impair the flavor of various foods as contents and have excellent preservability and sealability. Things.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that an oxygen-absorbing layer comprising an oxygen-absorbing resin composition containing an oxygen-absorbing composition has been formed. A saturated polyester resin, a polycarbonate resin, a mixed resin of a saturated polyester resin and a polycarbonate resin, or a three-component copolymer resin having bisphenol A, diphenyl carbonate and 1,10-decanedicarboxylic acid as constituent units inside the intermediate layer. Using a composite sheet provided with a gas barrier layer made of a polyamide resin in which 90% by mole or more of diamine units are meta-xylylenediamine units and a support layer made of a polyolefin resin on the outside of the intermediate layer. A sealed container in which a lid having gas barrier properties is sealed in a molded container holds various foods as contents. Without compromising the flavor
The inventors have found that they have excellent storage stability and sealing properties, and have completed the present invention based on this finding. That is, the present invention provides (1) (A) a saturated polyester resin, a polycarbonate resin, a mixed resin of a saturated polyester resin and a polycarbonate resin, or a three-component composition comprising bisphenol A, diphenyl carbonate, and 1,10-decanedicarboxylic acid. Perfume-retaining layer composed of a copolymer resin, (B) an oxygen-absorbing layer composed of an oxygen-absorbing resin composition containing an oxygen-absorbing composition, and (C) at least 90 mol% of diamine units are meta-xylylenediamine units. (2) a composite sheet having a gas barrier layer made of a polyamide resin and a support layer made of a polyolefin resin (D);
(E) The composite sheet according to (1), further comprising a concealing layer made of a polyolefin resin containing a pigment between the (A) fragrance-retaining layer and (B) the oxygen-absorbing layer, and (3) the (C) gas barrier layer. (1) the composite sheet according to (1), comprising a mixed resin of a polyamide resin and an amorphous polyamide in which 90% by mole or more of the diamine unit is a meta-xylylenediamine unit;
Using the composite sheet according to item (2) or (3)
(D) A sealed container characterized by forming a container so that the support layer is the outermost layer and sealing the container with a lid having gas barrier properties.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The composite sheet of the present invention has (A) a scent-retaining layer, (B) an oxygen absorbing layer, (C) a gas barrier layer, and (D) a support layer. In the composite sheet of the present invention,
(A) The scent-retaining layer is made of a saturated polyester resin, a polycarbonate resin, a mixed resin of a saturated polyester resin and a polycarbonate resin, or a three-component copolymer resin having bisphenol A, diphenyl carbonate and 1,10-decanedicarboxylic acid as constituent units. It is formed. There is no particular limitation on the saturated polyester resin forming the scent-retaining layer, and examples thereof include a polyethylene terephthalate resin, a polybutylene terephthalate resin, and a 1,4-cyclohexanedimethanol copolymerized polyester resin. There is no particular limitation on the polycarbonate resin forming the scent retention layer,
For example, bisphenol A polycarbonate resin, branched bisphenol A polycarbonate resin, modified aromatic polycarbonate resin and the like can be mentioned. Bisphenol A, diphenyl carbonate, and 1,10-decanedicarboxylic acid, which form a scent-retaining layer, are used as structural units 3
In the component copolymer resin, the molar ratio of bisphenol A to 1,10-decanedicarboxylic acid is preferably from 70:30 to 95: 5, more preferably from 80:20 to 92: 8. Further, diphenyl carbonate is preferably polymerized by using an equimolar number with bisphenol A.

[0006] Among the materials forming the scent-retaining layer, a three-component copolymer resin containing bisphenol A, diphenyl carbonate and 1,10-decanedicarboxylic acid as constitutional units can be particularly preferably used. This three-component copolymer resin is excellent in the flavor retention and heat sealing properties of the contents. Further, the three-component copolymer resin has excellent heat resistance and can withstand heating such as retort sterilization.
Among the three components, the 1,10-decanedicarboxylic acid component is
The bisphenol A component and the diphenyl carbonate component contribute to improvement in heat sealability, and contribute to improvement in heat resistance and fragrance retention. By copolymerizing a 1,10-decanedicarboxylic acid component having a long aliphatic chain, it is possible to improve the heat sealing property. If the sealant layer of the lid material is made of heat sealing polyethylene terephthalate, bisphenol A While the minimum heat sealing temperature of polycarbonate is 230 ° C., the three-component copolymer resin can be heat sealed from 200 ° C.
If the copolymerization molar ratio of 1,10-decanedicarboxylic acid is less than 5% in the three-component copolymer resin, the effect of improving the heat sealability may be insufficient. 1,10-
If the copolymerization molar ratio of decanedicarboxylic acid exceeds 30%, the fragrance retention may decrease. In the composite sheet of the present invention, the thickness of the scent-retaining layer is preferably from 5 to 100 µm, more preferably from 20 to 50 µm. If the thickness of the scent-retaining layer is less than 5 μm, the scent-retaining property may be reduced. If the thickness of the scent-retaining layer exceeds 100 μm, the sealing property with the lid and the sheet formability may be reduced. Saturated polyester resin, polycarbonate resin, mixed resin of saturated polyester resin and polycarbonate resin, or bisphenol A, diphenyl carbonate and 1,10-decanedicarboxylic acid as structural units 3
By providing a fragrance layer made of a component copolymer resin and molding the container with the fragrance layer as the innermost layer, the flavor of the contents of the container is absorbed by the innermost layer of the container, and the content of the container from the innermost layer to the container contents The transfer of odor can be suppressed, and the flavor of the food in the contents of the container can always be kept fresh.

In the composite sheet of the present invention, (B) the oxygen absorbing layer is formed from an oxygen-absorbing resin composition containing a deoxidizer composition. There is no particular limitation on the oxygen scavenger composition to be added to the oxygen-absorbing resin composition. For example, metal powders such as iron powder, reducing inorganic substances such as iron compounds, polyhydric phenols, polyhydric alcohols, ascorbin An oxygen scavenger composition using a reducing organic substance such as an acid or a salt thereof, a metal complex, or the like as a main agent of the oxygen absorption reaction can be used. Among these, an oxygen scavenger composition containing iron powder as a main component is preferable, and an oxygen scavenger composition including iron powder and a metal halide is more preferable. By using iron powder whose surface is coated with a metal halide, the composite sheet can be made to have excellent deoxidation performance. The iron powder used in the oxygen scavenger composition is not particularly limited as long as it can be dispersed in the thermoplastic resin and can cause a deoxidation reaction.
A known iron powder used as a deoxidizer can be used. The iron powder preferably has an average particle size of 5 to 200 μm, more preferably 5 to 50 μm.
When the average particle size of the iron powder is less than 5 μm, the workability may be reduced due to dust or the like. If the average particle size of the iron powder exceeds 200 μm, the surface area of the iron powder becomes relatively small, the oxygen absorption rate decreases, and the smoothness of the oxygen absorption layer may be impaired.

[0008] The metal halide used in the oxygen scavenger composition is not particularly limited, and examples thereof include chlorides, bromides and iodides of alkali metals or alkaline earth metals. Among them, chlorides of lithium, potassium, sodium, magnesium, calcium and barium can be particularly preferably used. The compounding amount of the metal halide is preferably from 0.1 to 20 parts by weight, more preferably from 0.1 to 5 parts by weight, per 100 parts by weight of iron powder. By adhering the metal halide to the iron powder, the amount of the metal halide can be reduced. The oxygen scavenger composition preferably has a low water content. The water content of the oxygen scavenger composition is
It is preferably at most 0.2% by weight, more preferably at most 0.1% by weight. When the composite sheet and the sealed container of the present invention are used after being filled with food or the like, the oxygen scavenger composition absorbs moisture and exhibits an oxygen scavenging function. The resin containing the oxygen scavenger composition has a Vicat softening point of 11
It is preferably a thermoplastic resin of 0 to 130 ° C. By using a thermoplastic resin having a Vicat softening point of 110 to 130 ° C, it is possible to prevent local overheating around the iron powder in the resin during thermoforming of the composite sheet, and to form a container having a good appearance. It is possible to do. As the thermoplastic resin to be used, for example, polyolefins such as polyethylene, polypropylene, polybutadiene, and polymethylpentene, elastomers, modified products thereof, and mixed resins thereof can be used. Among these, polyethylene, polypropylene, a mixed resin of polyethylene and polypropylene, a propylene-ethylene random copolymer, and a mixed resin thereof can be suitably used.

The mixing ratio of the oxygen-absorbing composition in the oxygen-absorbing resin composition is preferably from 2 to 93% by weight, more preferably from 10 to 70% by weight. If the compounding ratio of the oxygen scavenger composition is less than 2% by weight, the oxygen scavenging performance may not be sufficiently exhibited. If the compounding ratio of the oxygen scavenger composition exceeds 93% by weight, the moldability of the composite sheet may deteriorate. In addition, it is preferable to add calcium oxide to the oxygen-absorbing resin composition containing the oxygen-absorbing composition, in order to prevent foaming and to improve the aging property, and further, if necessary, an organic or inorganic resin. Colorants such as dyes and pigments, dispersants such as silanes and titanates, polyacrylic acid-based water absorbing agents, fillers such as silica and clay, and gas adsorbents such as zeolite and activated carbon can be added. In the composite sheet of the present invention, the thickness of the oxygen-absorbing layer composed of the oxygen-absorbing resin composition is from 10 to
1,000 μm, preferably 50-500 μm
m is more preferable. Oxygen absorption layer thickness is 10
If it is less than μm, the deoxygenation performance may not be sufficiently exhibited. If the thickness of the oxygen absorbing layer exceeds 1,000 μm, sheet formability may be reduced. By providing an oxygen-absorbing layer composed of an oxygen-absorbing resin composition containing the oxygen-absorbing composition, the oxygen-absorbing composition can exhibit the oxygen-absorbing function by absorbing moisture from the contents filled in the container. When the container is filled with the contents, it absorbs the oxygen gas in the space inside the container that is slightly present and the oxygen gas dissolved in the contents itself, and the inside of the container becomes a state without oxygen Therefore, the contents that are susceptible to deterioration due to oxidation can be kept fresh. In addition, even a small amount of oxygen gas that enters beyond the gas barrier layer is absorbed in the oxygen absorption layer, and the influence on the contents can be prevented.

[0010] In the composite sheet of the present invention, the gas barrier layer (C) comprises a polyamide resin in which at least 90 mol% of the diamine units are meta-xylylenediamine units. In the present invention, the gas barrier layer can be composed of only a polyamide resin in which 90 mol% or more of the diamine units are meta-xylylenediamine units, or 90 mol% or more of the diamine units are meta-xylylene diamine units. It may be a mixed resin of a polyamide resin and another thermoplastic resin. 9 of diamine units
Examples of the polyamide resin in which 0 mol% or more is a metaxylylenediamine unit include a polyamide obtained by a polycondensation reaction between metaxylylenediamine and adipic acid. Such a polycondensate of meta-xylylenediamine and adipic acid is also called nylon MXD6. The method for producing the polycondensate of metaxylylenediamine and adipic acid is not particularly limited. In addition to metaxylylenediamine and adipic acid, various derivatives such as metaxylylenediamine hydrochloride, and acid halides of adipic acid And various derivatives such as esters as starting materials. A polyamide resin in which 90 mol% or more of the diamine unit is a metaxylylenediamine unit can be copolymerized with a diamine or dicarboxylic acid other than metaxylylenediamine and adipic acid, and further has an amino acid having an amino group and a carboxyl group. Alternatively, a lactam can be copolymerized. In the composite sheet of the present invention,
When the metaxylylenediamine unit of the polyamide resin forming the gas barrier layer is less than 90 mol% of the diamine unit, the gas barrier property is insufficient and a large amount of oxygen gas enters,
The oxygen absorbing ability of the oxygen absorbing layer may be reduced in a short period of time.

In the composite sheet of the present invention, an amorphous polyamide can be mixed with a polyamide resin in which at least 90 mol% of the diamine units forming the oxygen absorbing layer are meta-xylylenediamine units. 90 in diamine units
By mixing an amorphous polyamide with a polyamide resin in which at least mol% is a meta-xylylenediamine unit,
Formability of the composite sheet can be improved. Amorphous polyamide is also called amorphous nylon or transparent nylon, and unlike linear aliphatic nylon such as nylon 6 and nylon 66, crystallization of the polymer hardly occurs or the crystallization rate is low. Very small special nylon. Examples of the amorphous polyamide used in the present invention include a polycondensation product of terephthalic acid and trimethylhexamethylenediamine, and a copolycondensation of 2,2-bis (p-aminocyclohexyl) propane with adipic acid and azelaic acid. A copolycondensate of bis (3-methyl-4-aminocyclohexyl) methane with isophthalic acid and ω-aminododecanoic acid, a copolycondensate of diphenylmethane diisocyanate with a mixture of adipic acid, azelaic acid and isophthalic acid, Copolycondensates of terephthalic acid and isophthalic acid with hexamethylenediamine and the like can be mentioned. Amorphous polyamide used in the present invention,
Test conditions according to ASTM D1238, ie
The melt flow rate at a temperature of 230 ° C. and a load of 2.16 kgf is preferably 8 g / 10 minutes or less, and 6 g /
More preferably, it is 10 minutes or less. When the melt flow rate of the amorphous polyamide exceeds 8 g / 10 minutes, the viscosity of the resin of the gas barrier layer becomes too low at the time of forming the composite sheet, so that it may be difficult to obtain a composite sheet having a stable thickness. . The amorphous polyamide preferably has a glass transition point of 80 to 150 ° C. By using an amorphous polyamide having a glass transition point of 80 to 150 ° C., when forming a composite sheet into a container, unevenness in elongation and thickness unevenness due to crystallization of the resin is prevented, and a wide range of heat molding conditions can be used. Good molding of the container becomes possible. For example, even when the sheet surface temperature in thermoforming is high or low, or when the heating time is long or short, unevenness in stretching and unevenness in thickness hardly occur, and the thermoforming workability of the composite sheet can be improved.

In the composite sheet of the present invention, the mixing ratio of the polyamide resin having at least 90 mol% of the diamine unit to the metaxylylenediamine unit and the amorphous polyamide is 3
The ratio is preferably 0:70 to 80:20 (weight ratio), and more preferably 40:60 to 80:20 (weight ratio). 20% by weight of amorphous polyamide
If it is less than 30, there is a possibility that a sufficient effect of improving the processability of forming the composite sheet into a container may not be obtained. If the mixing ratio of the amorphous polyamide exceeds 70% by weight, there will be a problem in the moldability of the composite sheet, or the properties of the polyamide resin in which 90 mol% or more of the diamine units are meta-xylylenediamine units will be impaired. There is a risk. The mixing ratio of the polyamide resin and the amorphous polyamide in which at least 90 mol% of the diamine units are meta-xylylenediamine units is 30: 7.
By setting the ratio to 0 to 80:20 (weight ratio), a composite sheet having good thermoformability can be obtained while maintaining high gas barrier properties of the polyamide resin, particularly high oxygen barrier properties when exposed to high temperature and high humidity conditions. Obtainable. In the composite sheet of the present invention, the thickness of the gas barrier layer is 5 to 100 μm
And more preferably 10 to 70 μm. If the thickness of the gas barrier layer is less than 5 μm, the oxygen absorbing ability may decrease with time.

In the composite sheet of the present invention, (D) the support layer is formed from a polyolefin resin. The scent-retaining layer, the oxygen-absorbing layer and the gas-barrier layer only need to have a thickness that exhibits the respective functions of scent-retaining property, oxygen-absorbing property and gas-barrier property. With only three layers, it is usually difficult to provide thermoformability for molding into a container and strength and rigidity for use as a closed container. Therefore, by providing the support layer as the outermost layer, it is possible to impart necessary thermoforming workability and strength and rigidity as a container. Further, the support layer also functions as a water vapor barrier layer. The polyolefin resin forming the support layer is not particularly limited, and examples thereof include polyethylene, polypropylene, an ethylene-propylene random copolymer, and an ethylene-propylene block copolymer. The polyolefin resin preferably has a melt flow rate of 5 g / 10 minutes or less, more preferably 2 g / 10 minutes or less. If the melt flow rate of the polyolefin resin exceeds 5 g / 10 minutes, the drawdown during thermoforming increases, and it may be difficult to obtain a good molded product. Pigments can be added to the polyolefin resin constituting the support layer, if necessary.
The pigment to be blended is not particularly limited, but titanium oxide, which is a white pigment, can be particularly preferably used. By blending titanium oxide, the rigidity of the support layer can be improved, and the aesthetics of the composite sheet and the sealed container can be improved by its hiding power. In the composite sheet of the present invention, the thickness of the support layer is preferably from 100 to 1,000 μm, more preferably from 300 to 600 μm. If the thickness of the support layer is less than 100 μm, the formability of the composite sheet becomes poor, and the strength and rigidity of the closed container may be insufficient.

In the composite sheet of the present invention, (E)
A concealing layer made of a polyolefin resin containing a pigment can be provided between (A) the scent-retaining layer and (B) the oxygen-absorbing layer.
Usually, the oxygen-absorbing layer is colored and the scent-retaining layer does not have sufficient hiding power, so by providing a concealing layer between the scent-retaining layer and the oxygen-absorbing layer, the colored oxygen-absorbing layer is The cover, the composite sheet, and the beauty of the closed container can be improved. The pigment to be blended is not particularly limited, but titanium oxide, which is a white pigment, can be particularly preferably used. When blending titanium oxide, the blending amount is preferably 2 to 20 phr based on the polyolefin resin. The concealing layer, together with the support layer, can also contribute to improving the thermoforming processability of the composite sheet and the strength and rigidity as a container. In the composite sheet of the present invention, the thickness of the concealing layer is 1
It is preferably from 0 to 100 μm. There is no particular limitation on the polyolefin resin forming the concealing layer, and examples thereof include polyethylene, polypropylene, an ethylene-propylene random copolymer, and an ethylene-propylene block copolymer. Polyolefin resin is
The melt flow rate is preferably 5 g / 10 minutes or less, more preferably 2 g / 10 minutes or less.
In the composite sheet of the present invention, if necessary, (A) between the fragrance preserving layer and (E) the concealing layer, (B) between the oxygen absorbing layer and (C) the gas barrier layer, (C) the gas barrier layer and ( D) An adhesive layer can be provided between the support layers. There is no particular limitation on the adhesive used for the adhesive layer, and examples thereof include maleic anhydride-modified polypropylene. By providing the adhesive layer, the adhesive strength of (A) the fragrance-retaining layer and (E) the concealing layer, (B) the oxygen absorbing layer and (C) the gas barrier layer, and (C) the adhesive strength of the gas barrier layer and (D) the support layer are improved. can do. There is no particular limitation on the method for producing the laminate that is the composite sheet of the present invention. For example, the laminate is produced using a known lamination technique such as a coextrusion method, a coextrusion lamination method, an extrusion lamination method, and a dry lamination method. be able to.

The closed container of the present invention is obtained by forming a container using the composite sheet of the present invention so that the support layer (D) is the outermost layer, and sealing it with a lid having gas barrier properties. There is no particular limitation on the method of forming the composite sheet into a container, and for example, it can be formed using a known forming method such as a vacuum forming method, a pressure forming method, or a vacuum pressure forming method.
The lid used in the present invention is not particularly limited as long as it is sealable with the scent-retaining layer and has a gas barrier property. For example, the sealant layer is made of heat-sealable polyethylene terephthalate, and the gas barrier layer is made of vinylidene chloride. Examples thereof include a three-layer film in which the polymer and the outermost layer are nylon, a three-layer film in which the sealant layer is heat-sealing polyethylene terephthalate, the gas barrier layer is aluminum foil, and the outermost layer is polyethylene terephthalate. Further, the lid is not limited to a film shape, but may be a molded product. For example, a multilayer sheet in which the sealant layer is a heat-sealable polyethylene terephthalate, the gas barrier layer is an ethylene vinyl alcohol copolymer, and the outermost layer is polypropylene can be formed into a lid shape by vacuum forming and used. Further, the composite sheet of the present invention itself can be used as a lid. The method of sealing the container molded using the composite sheet of the present invention with these lids is not particularly limited. For example, the container can be sealed using a heat sealing method, an ultrasonic sealing method, a high frequency sealing method, or the like. it can. FIG.
1 is a partial cross-sectional view of one embodiment of the composite sheet of the present invention.
The composite sheet of the present embodiment is formed by laminating a fragrance retention layer 1, an oxygen absorption layer 2, a gas barrier layer 3, and a support layer 4 in this order. FIG. 2 is a partial cross-sectional view of another embodiment of the composite sheet of the present invention. In the composite sheet of the present embodiment, the concealing layer 5 is provided between the scent-retaining layer 1 and the oxygen-absorbing layer 2. Thus, the gas barrier layer and the support layer are bonded to each other by the adhesive layer 8.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In Examples and Comparative Examples,
The following resin was used. (1) Perfume layer (a) Polycarbonate resin [Sumitomo Dow Co., Ltd., Caliber
200-13]. (b) Saturated polyester resin [Eastman Chemical
EASTAR PETG 6763]. (c) A three-component copolymer resin, a copolymer resin of bisphenol A: diphenyl carbonate: 1,10-decanedicarboxylic acid having a molar ratio of 91: 91: 9. (2) Concealing layer A polypropylene resin [Sumitomo Chemical Co., Ltd., Sumitomo Noblen FH1016] blended with 15 phr of titanium oxide [Dainippon Ink Chemical Industry Co., Ltd., Peoni S10123]. (3) Oxygen-absorbing layer Iron powder having an average particle size of 35 μm and a maximum particle size of 80 μm was placed in a vacuum mixer / dryer equipped with a heating jacket at 130 ° C., 10 mm
While heating and drying under reduced pressure of Hg, 3 parts by weight of a mixed aqueous solution mixed at a ratio of calcium chloride: water = 1: 1 to 100 parts by weight of iron powder is sprayed to cause calcium chloride to adhere to the surface of the iron powder. A granular oxygen absorber composition was prepared, and the oxygen absorber composition and a polypropylene resin [Sumitomo Chemical Co., Ltd.,
An oxygen-absorbing resin obtained by kneading and extruding with Sumitomo Noblen FH1016] at a weight ratio of 2: 3. (4) Gas barrier layer (a) MX nylon [Mitsubishi Gas Chemical Co., Ltd., nylon MXD
6]. (b) MX nylon-amorphous nylon, MX nylon [Mitsubishi Gas Chemical Co., Ltd., nylon MXD6] 50% by weight and amorphous nylon [Mitsui DuPont Polychemical Co., Ltd., Sealer P
A3426] mixture with 50% by weight. (c) Ethylene vinyl alcohol copolymer, EVOH
[Kuraray Co., Ltd., EVAL F101AZ]. (5) Support layer A polypropylene resin [Sumitomo Chemical Co., Ltd., Sumitomo Noblen FH1016] blended with 10 phr of titanium oxide [Dainippon Ink Chemical Co., Ltd., Peoni S10123]. (6) Adhesive layer (a) Maleic anhydride-modified polyethylene [Mitsui Chemicals, Inc.
Admer SF710]. (b) Maleic anhydride-modified polypropylene [Mitsui Chemicals
Admer QF305]. In Examples and Comparative Examples, a composite sheet was prepared by a co-extrusion method, and a diameter of 80 mm was obtained using an indirect heating type vacuum forming machine.
mm, a height of 50 mm, and a bottom diameter of 40 mm were molded. The resulting container was filled with orange juice or curry as contents. Orange juice is hot-filled at 60 ° C,
The curry was subjected to retort sterilization at 120 ° C. for 30 minutes after filling. In Examples 1 to 4 and Comparative Example 2, a gas barrier laminated film composed of a heat-sealable polyethylene terephthalate film having a thickness of 20 μm, an aluminum foil having a thickness of 10 μm, and an unstretched polypropylene film having a thickness of 50 μm was used as a lid. Heat sealed. Also,
In Comparative Example 1, a gas barrier laminated film consisting of a 20 μm-thick unstretched polypropylene film / a 10 μm-thick aluminum foil / a 50 μm-thick unstretched polypropylene film was heat-sealed as a lid. Fill with orange juice and curry and add 1 at room temperature
After storing for a month, the flavor retention and food applicability were evaluated by the following methods. (1) Retention of flavor of orange juice The amount of limonene, which is a component of orange juice, adsorbed to the innermost layer was measured.
(A lot) was evaluated in three stages. (2) Flavor retention of curry A taste test of the contents was carried out. ○ (no change in flavor is observed), Δ (a slight change in flavor is observed), × (change in flavor such as plastic odor is felt) Is evaluated) in three steps. (3) Food applicability of orange juice In addition to measuring the vitamin C content of orange juice, tasting was carried out, and ○ (the decrease in vitamin C content is small and the taste is good), △ (vitamin C content is reduced) Somewhat,
The evaluation was made on three scales: x (a slight change in taste was observed) and x (a large decrease in the amount of vitamin C, and a change in taste was also observed). (4) Food applicability of curry The degree of oxidation of oil was measured, and ○ (there is little oxidation of the oil), Δ (slight oxidation of the oil was recognized), × (the degree of oxidation of the oil was large) Was evaluated in three steps. Example 1 A polycarbonate resin having a thickness of 40 μm for the fragrance retention layer, a maleic anhydride-modified polyethylene having a thickness of 15 μm for the adhesive layer,
A masking layer having a thickness of 50 μm, a titanium oxide-containing polypropylene resin, an oxygen absorbing layer having a thickness of 200 μm,
An adhesive layer having a thickness of 15 μm maleic anhydride-modified polypropylene, a gas barrier layer having a thickness of 50 μm MX nylon,
A composite sheet in which the adhesive layer was a maleic anhydride-modified polypropylene having a thickness of 15 μm, and the support layer was a titanium oxide-containing polypropylene resin having a thickness of 400 μm, was evaluated. In the flavor retention test of orange juice, the adsorption of limonene to the scent-retaining layer was very low. In the flavor retention test of the curry, no change was found in the flavor of the contents. In the food applicability test of the orange juice, the decrease in the amount of vitamin C was small and the taste was good. In the food applicability test of curry, there was almost no oxidation of oil. Example 2 The same composite sheet as in Example 1 was produced and evaluated except that the gas barrier layer was made of MX nylon-amorphous nylon having a thickness of 50 μm. In the flavor retention test of orange juice, the adsorption of limonene to the scent-retaining layer was very low. In the flavor retention test of the curry, no change was found in the flavor of the contents. In the food applicability test of the orange juice, the decrease in the amount of vitamin C was small and the taste was good. In the food applicability test of curry, there was almost no oxidation of oil. Example 3 The same composite sheet as in Example 2 was produced and evaluated, except that the fragrance retaining layer was a three-component copolymer resin having a thickness of 40 μm. In the flavor retention test of orange juice, the adsorption of limonene to the scent-retaining layer was very low. In the flavor retention test of the curry, no change was found in the flavor of the contents. In the food applicability test of the orange juice, the decrease in the amount of vitamin C was small and the taste was good. In the food applicability test of curry, there was almost no oxidation of oil. Example 4 The same composite sheet as in Example 2 except that the scent-retaining layer was a 40 μm-thick saturated polyester resin and the adhesive layer between the scent-retaining layer and the hiding layer was 15 μm-thick maleic anhydride-modified propylene. Was prepared and evaluated. In the flavor retention test of orange juice, the adsorption of limonene to the scent-retaining layer was very low. In the flavor retention test of the curry, no change was found in the flavor of the contents.
In the food applicability test of the orange juice, the decrease in the amount of vitamin C was small and the taste was good. In the food applicability test of curry, there was almost no oxidation of oil. Comparative Example 1 The concealing layer is a 50 μm thick titanium oxide-containing polypropylene resin, the oxygen absorbing layer is a 200 μm thick oxygen absorbing resin,
An adhesive layer having a thickness of 15 μm maleic anhydride-modified polypropylene, a gas barrier layer having a thickness of 50 μm MX nylon,
A composite sheet having a 15 μm-thick maleic anhydride-modified polypropylene and a 400 μm-thick titanium oxide-containing polypropylene resin having a thickness of 400 μm and having no perfume-retaining layer was prepared and evaluated. In the flavor retention test of orange juice, the adsorption of limonene to the concealing layer was high. In the flavor retention test of the curry, a plastic odor was felt and a change in flavor was recognized. In the food applicability test of orange juice, vitamin C
The amount decreased little and the taste was good. In the food applicability test of curry, there was almost no oxidation of oil. Comparative Example 2 A polycarbonate resin having a thickness of 40 μm for the fragrance retention layer, a maleic anhydride-modified polyethylene having a thickness of 15 μm for the adhesive layer,
A masking layer having a thickness of 50 μm, a titanium oxide-containing polypropylene resin, an oxygen absorbing layer having a thickness of 200 μm,
The adhesive layer is a maleic anhydride-modified polypropylene having a thickness of 15 μm, the gas barrier layer is an ethylene vinyl alcohol copolymer having a thickness of 50 μm, the adhesive layer is a maleic anhydride-modified polypropylene having a thickness of 15 μm, and the support layer is 400 μm.
A composite sheet, which is a polypropylene resin containing titanium oxide, was prepared and evaluated. In the flavor retention test of orange juice, the adsorption of limonene to the scent-retaining layer was small. In the flavor retention test of curry,
A slight change in flavor was noted. In the food applicability test of orange juice, the amount of vitamin C decreased slightly,
There was also a slight change in taste. In the food applicability test of curry, slight oxidation of oil was observed. Table 1 shows the configurations and evaluation results of the composite sheets of Examples 1 to 4 and Comparative Examples 1 and 2.

[0017]

[Table 1]

From the results shown in Table 1, it can be seen that the sealed containers formed from the composite sheets of the present invention of Examples 1 to 4 are excellent in flavor retention and food applicability. On the other hand, Comparative Example 1 molded from a composite sheet having no perfume-retaining layer
In the closed container, flavor retention is poor, flavor is impaired, and the sealed container of Comparative Example 2 molded from a composite sheet using an ethylene vinyl alcohol copolymer for the gas barrier layer has good flavor retention and food applicability. I understand that there is no.

[0019]

The composite sheet and sealed container of the present invention can be easily manufactured, and the oxygen gas in the container is removed after filling the contents, so that the conventional plastic gas barrier multilayer container is used. It is excellent in fragrance retention and can be stably stored for a long period of time without changing the flavor of the contents.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of one embodiment of the composite sheet of the present invention.

FIG. 2 is a partial cross-sectional view of another embodiment of the composite sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fragrance retention layer 2 Oxygen absorption layer 3 Gas barrier layer 4 Support layer 5 Concealment layer 6 Adhesive layer 7 Adhesive layer 8 Adhesive layer

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B32B 27/32 B32B 27/32 D 27/36 27/36

Claims (4)

[Claims] (A) A saturated polyester resin, a polycarbonate resin, a mixed resin of a saturated polyester resin and a polycarbonate resin, or a three-component copolymer resin having bisphenol A, diphenyl carbonate and 1,10-decanedicarboxylic acid as constituent units. (B) an oxygen-absorbing layer comprising an oxygen-absorbing resin composition containing an oxygen-absorbing composition, and (C) a polyamide resin in which 90% by mole or more of diamine units are meta-xylylenediamine units. A composite sheet comprising: a gas barrier layer comprising: a support layer comprising a polyolefin resin; 2. The composite sheet according to claim 1, further comprising a concealing layer made of a polyolefin resin containing a pigment between (E) (A) a perfume-retaining layer and (B) an oxygen-absorbing layer. 3. The gas barrier layer according to claim 1, wherein the gas barrier layer comprises 90 units of diamine units.
The composite sheet according to claim 1, wherein the composite sheet comprises a mixed resin of a polyamide resin in which at least mol% is a metaxylylenediamine unit and an amorphous polyamide. 4. A container is formed using the composite sheet according to claim 1, 2 or 3 so that the support layer is the outermost layer, and is sealed with a lid having gas barrier properties. A sealed container characterized by becoming.