JP5000545B2 - Food packaging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbon-neutral food packaging body which is high in heat resistance, low in water vapor permeability, light in weight, and can be burned to generate no poisonous gas. <P>SOLUTION: The food packaging body is designed to comprise at least one layer which has at least a &beta;-pinene polymer at a content of 70% by mass or more, wherein the &beta;-pinene polymer has a glass transition point of &ge;80&deg;C and specific gravity of &ge;0.85 and lower than 1.0. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a food packaging body, and more particularly to a food packaging body having high heat resistance, low water vapor permeability, and light weight.

  Conventionally, vinyl chloride resins, vinylidene chloride resins, and the like have been frequently used as food packaging materials because of their excellent mechanical strength, elongation, gas barrier properties, transparency, and the like. However, in recent years, these halogen-containing resins have become a problem as a cause of causing environmental hazards by generating toxic gases at the time of incineration. For this reason, replacement with polymers not containing halogen atoms is desired. . Moreover, the request | requirement with respect to a food packaging body is a thing excellent in water vapor | steam barrier property in order to maintain the freshness of a foodstuff etc. is desired.

  Therefore, examples of using a norbornene-based resin in addition to polypropylene and polyethylene (see Patent Document 1), and examples of depositing an inorganic oxide on a resin film such as polyester or polyamide as a food packaging body having excellent water vapor barrier properties (Patent) Documents 2 to 4) have been proposed.

  Thus, the food packaging body on which such an inorganic oxide is deposited has the disadvantage that the inorganic oxide layer is cracked due to impact or bending and the water vapor barrier property is lowered. Is inexpensive and has a good water vapor barrier property, but has low heat resistance, leaving problems such as deformation due to use at a high temperature such as a microwave oven. On the other hand, norbornene-based resins have good heat resistance and water vapor barrier properties, but may be colored or discolored when irradiated with radiation such as electron beams. For this reason, the improvement of radiation resistance is desired especially for the cyclic olefin resin molded product used for such food applications.

  Furthermore, in recent years, a carbon neutral material that does not increase carbon dioxide is required from the viewpoint of environmental problems. For example, Patent Document 5 proposes to use carbon-neutral polylactic acid, which has a high water vapor permeability, is not sufficient in heat resistance, and is difficult to use practically. It was.

JP-A-11-217491 JP-A-9-76400 Japanese Patent Laid-Open No. 11-229119 JP 2000-103001A WO 1999/45067

  Here, the present invention has been made in the background of such circumstances, and the problem to be solved is to provide a food packaging body having high heat resistance, low water vapor permeability, and light weight. is there. Another object of the present invention is to provide a carbon neutral food package that does not generate toxic gas during incineration.

  And as a result of intensive studies to solve such problems, the present inventors have found that the intended food packaging can be advantageously obtained by using a predetermined β-pinene polymer. The present invention has been completed.

  That is, the present invention includes at least one layer containing at least 70% by mass of a β-pinene polymer having a glass transition temperature of 80 ° C. or more and a specific gravity of 0.85 or more and less than 1.0. The gist of the food package is as follows.

  In addition, according to one of the desirable embodiments of the food package according to the present invention, the β-pinene polymer is hydrogenated and ([hydrogenated olefinic double The number of bonds] / [number of olefinic double bonds in the polymer before hydrogenation]) × 100 is 95% or more.

Moreover, according to one of the preferable aspects of the food packaging body according to the present invention, the oxygen permeability under the conditions of 20 ° C. and 65% RH (relative humidity) is 1.0 cc / m ² · day · atm or less. A gas barrier layer is further included.

  Furthermore, according to one of the other preferable embodiments of the food package according to the present invention, at least one layer selected from a polyester layer, a polyamide layer and a polyolefin layer is further laminated.

  As described above, in the food package according to the present invention, a predetermined β-pinene polymer is used as a forming material, and the following characteristics are obtained depending on the excellent characteristics of the β-pinene polymer. It has a special effect.

(1) Since the β-pinene polymer used as a material for forming a food package is a polymer having a small specific gravity, the weight of the target food package can be advantageously reduced.
(2) Since such β-pinene polymer has high heat resistance and low water absorption, it is possible to effectively prevent deformation due to heat and water absorption / desorption.
(3) The food package according to the present invention can be advantageously thinned because the elastic modulus and impact resistance are highly balanced.
(4) Since the food packaging body obtained by the present invention has low water vapor permeability, it is difficult for moisture to pass through the inside of the food packaging body, and it is possible to suppress deterioration of the food inside.
(5) The food package according to the present invention has a feature that no harmful gas is generated even if it is disposed of and then incinerated.
(6) The food package according to the present invention is easy to check the food inside because of its high transparency.
(7) Since the food packaging body according to the present invention has high light resistance, it has an advantage that the performance is not deteriorated when used for a long time.
(8) Since the β-pinene polymer used in the present invention can be obtained from a raw material derived from a natural product, it is a carbon neutral material and has environmentally friendly characteristics.

  By the way, the β-pinene polymer used as a material for forming food packaging in the present invention has a specific gravity of 0.85 or more and less than 1.0 and a glass transition temperature of 80 ° C. or more. It is a coalescence. Here, the β-pinene polymer in the present specification and claims refers to a polymer (polymer) having a β-pinene content of 50% by mass or more. In the food packaging according to the present invention, a β-pinene polymer having a β-pinene content of 60% by mass or more is advantageously used, and more preferably, the β-pinene content is 70% by mass or more. A β-pinene polymer is used.

  As the β-pinene used as a raw material for producing such β-pinene polymer, any conventionally known one can be used. For example, it is possible to use a terpene such as α-pinene collected from a plant or a petroleum-derived compound, as well as it can be directly used after purification from a plant such as pine or citrus. Β-pinene and the like produced according to a more known technique (for example, the technique disclosed in US Pat. No. 3,278,623) can also be used. The β-pinene polymer obtained by using such plant-derived β-pinene is a carbon neutral material, and in this respect, the food packaging according to the present invention is capable of forming a recycling society and global warming. It can contribute to the prevention of transformation.

  Further, the β-pinene polymer used in the present invention may be a homopolymer of the above-described β-pinene, or at least one kind of other copolymerizable monomers with β-pinene. There is no problem even if it is a copolymer of. Examples of monomers copolymerizable with β-pinene include cationic polymerizable monomers, radical polymerizable monomers, coordination polymerizable monomers, and plant-derived terpenes.

  In the present invention, the cationically polymerizable monomer, radically polymerizable monomer, and coordination polymerizable monomer that are used when producing the β-pinene polymer are generally used conventionally. It is possible to use what is. Plant-derived terpenes can also be used as the polymerizable monomer in any of the cationic polymerization method, radical polymerization method and coordination polymerization method. Specifically, as the cationic polymerizable monomer, isobutylene, isoprene, butadiene, styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, pt-butoxystyrene, indene, alkyl vinyl ether, norbornene Further, as the radical polymerizable monomer, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate (Meth) acrylates such as 2-hydroxypropyl (meth) acrylate and glycidyl (meth) acrylate; nitrile group-containing vinyl monomers such as acrylonitrile and methacrylonitrile; amide group-containing vinyl monomers such as acrylamide and methacrylamide Chromatography; vinyl acetate, vinyl pivalate, vinyl esters such as vinyl benzoate, vinyl chloride, vinylidene chloride, maleic anhydride, maleic acid, fumaric acid, fumaric acid esters, may be mentioned maleimide. Examples of coordination polymerizable monomers include ethylene, propylene, 1-hexene, cyclopentene, norbornene, and plant-derived terpenes include myrcene, alloocimene, omesin, α-pinene. , Dipentene, limonene, α-ferrandrene, α-terpinene, γ-terpinene, 2-carene, 3-carene and the like. Among these, one or more types are appropriately selected and used according to the amount of β-pinene used. Since the β-pinene polymer is advantageously obtained by the cationic polymerization method, among the polymerizable monomers as described above, the cationic polymerizable monomer is particularly advantageously used.

  In the case where the copolymerizable monomer is copolymerized with β-pinene, the amount of copolymerization is preferably 0.001 to 50% by mass in the polymer, and more preferably 0.01 to 20% by mass. Particularly preferred is 0.05 to 10% by mass. If the amount of copolymerization is too large, problems such as increased water absorption and reduced heat resistance are undesirable.

  On the other hand, a small amount of bifunctional or higher crosslinkable monomer (hereinafter referred to as a crosslinkable monomer) is copolymerized together with or in place of the above copolymerizable monomer. You can also Such a crosslinkable monomer is generally used as a branching agent or a crosslinking agent in the production of a polymer, but has a so-called long chain branching structure by reducing the amount used. A β-pinene polymer having a molecular weight that does not cause an insoluble part in an organic solvent is advantageously obtained. Specific examples of the crosslinkable monomer that can be used in the present invention include m-diisopropenylbenzene, p-diisopropenylbenzene, m-divinylbenzene, p-divinylbenzene, and 1,4-cyclohexanedimethanoldi. Bifunctional vinyl compounds such as vinyl ether and ethylene glycol divinyl ether can be mentioned, and among them, m-diisopropenylbenzene is preferably used from the viewpoints of economy and reactivity.

  When such a crosslinkable monomer is copolymerized with β-pinene (and a monomer copolymerizable with β-pinene), the copolymerization amount is 0.001 to 7% by mass in the polymer. Among them, 0.01 to 5% by mass is more preferable, and 0.05 to 4% by mass is most preferable. If the amount of copolymerization is too large, the resulting β-pinene polymer becomes gel and loses thermoplasticity, which is not preferable.

  By the way, the polymerization method of the β-pinene polymer used in the present invention is not particularly limited, and a known polymerization method suitable for the polymerizable monomer can be appropriately selected. For example, any one of an anionic polymerization method, a cationic polymerization method, a radical polymerization method and a coordination polymerization method can be selected and used, but in general, a cationic polymerization method is adopted.

In addition, when obtaining the beta-pinene polymer used by this invention according to a cationic polymerization method, a well-known cationic polymerization catalyst will be used suitably as the polymerization catalyst. Specifically, BF ₃ , BF ₃ OEt ₂ , BBr ₃ , BBr ₃ OEt ₂ , AlCl ₃ , AlBr ₃ , AlI ₃ , TiCl ₄ , TiBr ₄ , TiI ₄ , FeCl ₃ , FeCl ₂ , SnCl ₂ , SnCl ₄ , WCl ₆ , MoCl ₅ , SbCl ₅ , TeCl _2, etc., Group 3-16 group metal halogen compounds; HF, HCl, HBr, etc. hydrogen acids; H ₂ SO ₄ , H ₃ BO ₃ , HClO ₄ , oxo acids such as CH ₃ COOH, CH ₂ ClCOOH, CHCl ₂ COOH, CCl ₃ COOH, CF ₃ COOH, p-toluenesulfonic acid, CF ₃ SO ₃ H, H ₃ PO ₄ , P ₂ O ₅ , and these Polymer compounds such as ion exchange resins having a group; heteropolyacids such as phosphomolybdic acid and phosphotungstic acid; SiO ₂ , Al ₂ O ₃ , SiO ₂ -Al ₂ O ₃ , MgO-SiO ₂ , B ₂ O ₃ —Al ₂ O ₃ , WO ₃ —Al ₂ O ₃ , Zr ₂ O ₃ —SiO ₂ , sulfated zirconia, tungstate zirconia, zeolite exchanged with H ⁺ or rare earth elements, activated clay, acidic Examples thereof include solid acids such as solid phosphoric acid in which clay, γ-Al ₂ O ₃ , and P ₂ O ₅ are supported on diatomaceous earth.

These cationic polymerization catalysts may be used in combination, and other compounds may be added to the polymerization system. Such other compounds are compounds that can improve the activity of the catalyst, for example, by adding them. Specifically, examples of the compound that improves the activity of the above-mentioned metal halide as an acidic compound include MeLi, EtLi, BuLi, Et ₂ Mg, EtMgBr, Et ₃ Al, Et ₂ AlCl, EtAlCl ₂ , Et _3. Metal alkyl compounds such as Al ₂ Cl ₃ , (i-Bu) ₃ Al, Et ₂ Al (OEt), Me ₄ Sn, Et ₄ Sn, Bu ₄ Sn, Bu ₃ SnCl; 2-methoxy-2-phenylpropane; Examples thereof include compounds used as a polymerization initiator in living cationic polymerization, such as t-butanol, 1,4-bis (2-methoxy-2-propyl) benzene, and 2-phenyl-2-propanol.

  Further, as a polymerization method of the β-pinene polymer used in the present invention, a solution polymerization method using a solvent may be used. The solvent that can be used varies depending on the polymerization method employed, and thus it is difficult to define it uniquely. For example, aromatic hydrocarbon solvents such as benzene, toluene, xylene, etc .; pentane, hexane, heptane, Aliphatic hydrocarbon solvents such as octane, cyclopentane, cyclohexane, methylcyclohexane, decalin; halogenated hydrocarbon solvents such as methyl chloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethylene; esters, Examples thereof include oxygen-containing solvents such as ether. In view of reactivity, it is preferable to use an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent, a halogenated hydrocarbon solvent, or the like. These solvents may be used alone or in combination of two or more.

  Although the usage-amount of such a solvent is not specifically limited, About 100-10000 mass parts normally with respect to 100 mass parts of monomers, such as (beta) -pinene, Preferably it is 150-5000 mass parts, More preferably, it is 200- 3000 parts by mass. When the amount of the solvent is small, uniform mixing of the polymerization catalyst becomes difficult, so that the reaction becomes non-uniform, and a uniform polymer cannot be obtained, or the control of the reaction becomes difficult. On the other hand, when the amount of solvent is large, there is a problem that productivity is lowered.

  And when performing a polymerization reaction, -80 degreeC-100 degreeC is preferable normally, -40 degreeC-80 degreeC is more preferable especially, -20 degreeC-80 degreeC is the most preferable especially. If this reaction temperature is too low, the progress of the reaction is slow, and if it is too high, it becomes difficult to control the reaction and it is difficult to obtain reproducibility.

  Moreover, the reaction pressure for performing the polymerization reaction is not particularly limited, but is preferably 0.5 to 50 atm, and more preferably 0.7 to 10 atm. Usually, the polymerization reaction is performed at around 1 atm.

  Furthermore, the reaction time for conducting the polymerization reaction is not particularly limited, and the reaction time may be appropriately determined so that a β-pinene polymer is obtained in good yield according to conditions such as reaction temperature and reaction pressure. Good. Usually, it is about 0.01 to 24 hours, preferably 0.2 to 10 hours.

  By the way, the β-pinene polymer produced by the polymerization reaction can be obtained by, for example, reprecipitation, solvent removal under heating, solvent removal under reduced pressure, solvent removal with steam (steam stripping), etc. It can be separated and obtained from the reaction mixture by a normal operation in isolation from the solution.

The β-pinene polymer used in the present invention preferably has hydrogenated olefinic double bonds from the viewpoints of light resistance, impact resistance, heat resistance and the like. In general, the hydrogenation rate is preferably 90% or more, more preferably 95% or more, and most preferably 99% or more. . In the present invention, the β-pinene polymer is hydrogenated and shows the hydrogenation rate ([number of hydrogenated olefinic double bonds] / [before hydrogenation]). The number of olefinic double bonds in the polymer]]) × 100 is desirably 95% or more. The hydrogenation rate of the olefinic double bond (carbon-carbon double bond) in the hydrogenated polymer is determined by iodine titration method, infrared spectroscopic spectrum measurement, nuclear magnetic resonance spectrum ( ¹ H-NMR spectrum). It can be calculated using an analysis means such as measurement.

  Here, the method for hydrogenating the β-pinene polymer used in the present invention is not particularly limited, and a known method can be used. For example, homogeneous catalysts such as Wilkinson complex, cobalt acetate / triethylaluminum, nickel acetylacetonate / triisobutylaluminum, diatomaceous earth, magnesia, alumina, silica, alumina-magnesia, silica-magnesia, silica-alumina, synthetic zeolite, etc. A known method using a heterogeneous catalyst or the like in which a catalyst metal such as nickel, palladium, or platinum is supported on a support can be used.

  As a solvent that can be used for hydrogenation, any organic solvent that dissolves the polymer and is inert to the hydrogenation catalyst can be used. Specifically, aromatic hydrocarbon solvents such as benzene, toluene, xylene; aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, cyclopentane, cyclohexane, methylcyclohexane, decalin; methyl chloride, methylene chloride Halogenated hydrocarbon solvents such as 1,2-dichloroethane, 1,1,2-trichloroethylene; oxygen-containing solvents such as esters and ethers. In view of reactivity, aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents and the like are preferable. These solvents may be used alone or in combination of two or more.

Furthermore, although the reaction temperature of the hydrogenation reaction depends on the hydrogenation catalyst used and the hydrogen pressure, it is generally preferably about 20 ° C to 250 ° C, more preferably 25 ° C to 150 ° C, and even more preferably 40 ° C to 100 ° C. Is most preferred. If the reaction temperature is too low, the reaction will not proceed smoothly, and if the reaction temperature is too high, side reactions and molecular weight will tend to occur. The hydrogen pressure is preferably about normal pressure to about 200 kgf / cm ² , more preferably 5 to 100 kgf / cm ² . If the hydrogen pressure is too low, the reaction does not proceed smoothly, and if the hydrogen pressure is too high, there are restrictions on the apparatus.

  In addition, the density | concentration of (beta) -pinene polymer in such a hydrogenation reaction system is about 2 mass%-40 mass% normally, Preferably it is 3 mass%-30 mass%, More preferably, it is 5 mass%-20 % By mass. If the concentration of β-pinene polymer is low, productivity is likely to decrease, which is not preferable. Moreover, when the density | concentration of (beta) -pinene polymer is too high, the hydrogenated polymer may precipitate or the viscosity of a reaction mixture may become high and it may become difficult to perform stirring smoothly, and is unpreferable.

  The reaction time of the hydrogenation reaction depends on the hydrogenation catalyst used, the hydrogen pressure, and the reaction temperature, but is usually about 0.1 to 50 hours, preferably 0.2 to 20 hours, more preferably 0.5 hours to 10 hours will be employed.

  Furthermore, the β-pinene polymer after the hydrogenation reaction may be polymerized by, for example, reprecipitation, solvent removal under heating, solvent removal under reduced pressure, or solvent removal with steam (steam stripping). The product is separated and obtained from the reaction mixture by a normal operation for isolation from the solution.

  By the way, the molecular weight of the β-pinene polymer used in the present invention is 30,000 to 1,000,000 in terms of weight average molecular weight from the viewpoint of the viscosity and melt viscosity of the polymerization solution, moldability, strength of food packaging, heat resistance, and the like. It is preferably about 40,000 to 500,000, more preferably 60,000 to 250,000, and most preferably 90,000 to 200,000. The weight average molecular weight of the polymer can be calculated using a known analysis method such as gel permeation chromatography (GPC) obtained in terms of polystyrene or static light scattering measurement (SLS).

  In addition, the glass transition temperature (Tg) of the β-pinene polymer used in the present invention is preferably higher from the use environment of the food packaging body, and in order to avoid adverse effects due to heat, it is necessary to be 80 ° C. or higher. Among them, the temperature is preferably 100 ° C. or higher, more preferably 110 ° C. or higher. The upper limit of the glass transition temperature is not particularly defined, but is preferably about 200 ° C. This is because in an amorphous polymer such as the β-pinene polymer used in the present invention, if the glass transition temperature is too high, the entanglement of the polymer is reduced, and the molded product may become brittle.

  Furthermore, the total light transmittance of the β-pinene polymer used in the present invention is preferably higher, and generally 80% or more is preferable in the state of the layer containing the β-pinene polymer alone, and more preferably 85% or more. Is more preferable, and 90% or more is most preferable.

  Furthermore, the β-pinene polymer used in the present invention preferably has a lower water absorption rate from the viewpoint of dimensional stability. The water absorption of such β-pinene polymer is preferably 0.2% or less as saturated water absorption when placed in an atmosphere of 60 ° C. and 90% RH (relative humidity), and more preferably 0.1% or less. In particular, 0.05% or less is most preferable. A β-pinene polymer giving such a water absorption rate is advantageously selected.

  Such a β-pinene polymer used in the present invention is characterized by a low specific gravity. A lighter food package can be obtained because the specific gravity is small. Accordingly, the specific gravity of the β-pinene polymer used in the present invention needs to be 0.85 or more and less than 1.0, and more preferably 0.85 to 0.98. This is because it is difficult to obtain a polymer having a specific gravity smaller than 0.85, and when the specific gravity is 1.0 or more, the object of weight reduction cannot be sufficiently achieved.

The β-pinene polymer used in the present invention is characterized by a low water vapor permeability. The water vapor permeability when converted to a film thickness of 20 μm is preferably 20 g · 20 μm / m ² · day or less (under an atmosphere of 40 ° C.-90% RH).

  In addition, the β-pinene polymer for forming the food packaging according to the present invention may contain various known compounding agents alone or as necessary, as long as the object of the present invention is not impaired. Two or more types can be combined and mixed.

  Specific examples of such various compounding agents are not particularly limited as long as they are usually used in the resin industry. For example, antioxidants, ultraviolet absorbers, light stabilizers, near infrared absorption And compounding agents such as a colorant such as a colorant, a dye and a pigment, a lubricant, a plasticizer (softening agent), an antistatic agent, a fluorescent brightening agent, and a filler.

  Among them, examples of antioxidants include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc. Among them, phenolic antioxidants are preferable, and alkyl-substituted phenolic oxidations. Inhibitors are particularly preferred.

  As the phenolic antioxidant used here, specifically, conventionally known ones can be used. For example, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methyl Benzyl) -4-methylphenyl acrylate, 2,4-di-t-amyl-6- (1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate, etc. Acrylate compounds such as those described in JP-A-179953 and JP-A-1-168463; octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2′-methylene -Bis (4-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5- Limethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxy) Phenylpropionate) methane [i.e. pentaerythrimethyl-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenylpropionate)], triethylene glycol bis (3- (3-t-butyl- Alkyl-substituted phenolic compounds such as 4-hydroxy-5-methylphenyl) propionate); 6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bisoctylthio-1,3,5 -Triazine, 4-bisoctylthio-1,3,5-triazine, 2-octylthio-4,6-bis- (3,5-di-t-butyl-4-oxyani Roh) triazine group-containing phenol compounds such as 1,3,5-triazine.

The phosphorus antioxidant is not particularly limited as long as it is usually used in the general resin industry. For example, triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris ( Nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, 10- (3,5-di-t-butyl-4-hydroxybenzyl)- Monophosphite compounds such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tri Decylphosphite), 4,4′-isopropylidene-bis (phenyl-di-alkyl (C ₁₂ -C ₁₅ ) phosphite) And diphosphite-based compounds. Among these, monophosphite compounds are preferable, and tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite and the like are particularly preferable.

  Furthermore, examples of the sulfur antioxidant include dilauryl 3,3-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3-thiodipropionate, lauryl stearyl 3,3. -Thiodipropionate, pentaerythritol-tetrakis- (β-lauryl-thiopropionate), 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5,5 ] Undecane etc. can be mentioned.

  And these antioxidant can be used individually or in combination of 2 or more types, respectively. The blending amount of such an antioxidant is appropriately determined within a range where the object of the present invention is not impaired, but is usually 0.001 with respect to 100 parts by mass of the β-pinene polymer. It is about -5 mass parts, Preferably it is the range of 0.01-1 mass part.

  Examples of the ultraviolet absorber include 2- (2-hydroxy-5-methylphenyl) 2H-benzotriazole, 2- (3-t-butyl-2-hydroxy-5-methylphenyl) -5-chloro- 2H-benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chloro-2H-benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) ) -2H-benzotriazole, 5-chloro-2- (3,5-di-t-butyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (3,5-di-t-amyl-2-) Benzotriazole ultraviolet absorbers such as hydroxyphenyl) -2H-benzotriazole; 4-t-butylphenyl-2-hydroxybenzoate, phenyl-2-hydroxy Zoate, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate, 2- (2H- Benzotriazol-2-yl) -4-methyl-6- (3,4,5,6-tetrahydrophthalimidylmethyl) phenol, 2- (2-hydroxy-5-t-octylphenyl) -2H-benzotriazole Benzoate ultraviolet absorbers such as 2- (2-hydroxy-4-octylphenyl) -2H-benzotriazole; 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone -5-sulfonic acid trihydrate, 2-hydroxy-4-octyloxybenzophenone, 4 Benzophenone series such as dodecyloxy-2-hydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone UV absorbers; acrylate UV absorbers such as ethyl-2-cyano-3,3-diphenyl acrylate, 2′-ethylhexyl-2-cyano-3,3-diphenyl acrylate; [2,2′-thiobis (4- t-octylphenolate)]-2-ethylhexylamine nickel and other metal complex ultraviolet absorbers and the like can be used.

  Furthermore, examples of the light stabilizer include 2,2,6,6-tetramethyl-4-piperidylbenzoate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, and bis (1,2 , 2,6,6-pentamethyl-4-piperidyl) -2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate, 4- (3- (3,5 -Di-t-butyl-4-hydroxyphenyl) propionyloxy) -1- (2- (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy) ethyl) -2,2, Examples thereof include hindered amine light stabilizers such as 6,6-tetramethylpiperidine.

  In addition, as the near-infrared absorber, for example, cyanine-based near-infrared absorber; pyrylium-based near-infrared absorber; squarylium-based near-infrared absorber; croconium-based near-infrared absorber; Infrared absorbers; dithiol metal complex-based near infrared absorbers; naphthoquinone near infrared absorbers; anthraquinone near infrared absorbers; indophenol near infrared absorbers; As commercially available near infrared absorbers, SIR-103, SIR-114, SIR-128, SIR-130, SIR-132, SIR-152, SIR-159, SIR-162 (above, Mitsui Toatsu Dye Co., Ltd.) Company-made), Kayasorb IR-750, Kayasorb IRG-002, Kayasorb IRG-003, Kayasorb IR-820B, Kayasorb IRG-022, Kayasorb IRG-023, Kayasorb CY9, Kayasorb CY9, , Manufactured by Nippon Kayaku Co., Ltd.).

  The dye is not particularly limited as long as it is uniformly dispersed / dissolved in the β-pinene polymer to be used, but has excellent compatibility with the β-pinene polymer used in the present invention. Therefore, oil-soluble dyes (various CI solvent dyes) are widely used. Specific examples of the oil-soluble dye include “Color Index” published in The Society of Dyers and Colorists, Vol. 3. Various C.I. I. Solvent dyes may be mentioned.

  Among the pigments, organic pigments include, for example, diarylide pigments such as Pigment Red 38; azo lake pigments such as Pigment Red 48: 2, Pigment Red 53, and Pigment Red 57: 1; Pigment Red 144 and Pigment Red 166. Pigment Red 220, Pigment Red 221 and Pigment Red 248; condensed azo pigments such as Pigment Red 171, Pigment Red 175, Pigment Red 176, Pigment Red 185 and Pigment Red 208; Pigment Red 122 and the like Quinacridone pigments; perylene pigments such as Pigment Red 149, Pigment Red 178, and Pigment Red 179; and anthraquinone pigments such as Pigment Red 177. Examples of inorganic pigments include titanium oxide, carbon black, red pepper, chrome red, molybdenum red, resurge, and iron oxide.

  In addition, when coloring is required for the food packaging body of the present invention, any of the above dyes and pigments can be used within the scope of the object of the present invention, and is not particularly limited. In the case of a food package in which micro optical properties are a problem, coloring with a dye is preferable. In addition, the ultraviolet absorber may show a yellow to red color visually, and the near infrared absorber may show a black color visually, so there is no need to use these and dyes strictly, Moreover, there is no problem even if they are used in combination.

  As the lubricant, organic compounds such as aliphatic alcohol esters, polyhydric alcohol esters or partial esters, inorganic fine particles, and the like can be used. Here, examples of the organic compound include glycerol monostearate, glycerol monolaurate, glycerol distearate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, and the like.

  Further, as other lubricants, generally inorganic fine particles can be used. Here, the inorganic fine particles include oxides, sulfides, hydroxides, nitrides, halides, carbonates, sulfates, acetic acids of the elements of Groups 1, 2, 4, and 6-14 of the periodic table. Examples thereof include fine particles of salts, phosphates, phosphites, organic carboxylates, silicates, titanates, borates and their hydrates, composite compounds centered on them, natural compounds, and the like.

  Examples of the plasticizer include tricresyl phosphate, trixylenyl phosphate, triphenyl phosphate, triethylphenyl phosphate, diphenyl cresyl phosphate, monophenyl dicresyl phosphate, diphenyl monoxylenyl phosphate. Phosphate triester plasticizers such as phosphate, monophenyldixylenyl phosphate, tributyl phosphate, triethyl phosphate; dimethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di-phthalate Phthalate plasticizers such as 2-ethylhexyl, diisononyl phthalate, octyldecyl phthalate, and butylbenzyl phthalate; fatty acid monobasic acids such as butyl oleate and glycerol monooleate Plasticizers; dihydric alcohol ester plasticizers; oxyester plasticizers and the like can be used. Of these, phosphate triester plasticizers are preferred, and tricresyl phosphate and trixylenyl phosphate are preferred. Particularly preferred.

Furthermore, as specific examples of other plasticizers, squalane (C ₃₀ H ₆₂ , Mw = 422.8), liquid paraffin (white oil, ISO VG10, ISO VG15, ISO VG32, ISO VG32 as defined in JIS-K-2231) VG68, ISO VG100, ISO VG8 and ISO VG21), polyisobutene, hydrogenated polybutadiene, hydrogenated polyisoprene, and the like. Among these, squalane, liquid paraffin, and polyisobutene are preferably used.

  Furthermore, examples of the antistatic agent include long-chain alkyl alcohols such as stearyl alcohol and behenyl alcohol, fatty acid esters of polyhydric alcohols such as glycerol monostearate and pentaerythritol monostearate, and stearyl alcohol and behenyl alcohol. Particularly preferred.

  These compounding agents can be used alone or in admixture of two or more, and the mixing ratio is appropriately selected within a range not impairing the object of the present invention. The amount of the compounding agent described above is also appropriately selected within a range that does not impair the object of the present invention. However, for each compounding agent, the amount is usually 0. It is about 001-5 mass parts, Preferably it is the range of 0.01-1 mass part.

  Moreover, other polymer components can also be mix | blended with the beta-pinene polymer for shape | molding the food packaging body which concerns on this invention as one of the above-mentioned compounding agents as needed. Examples of other polymers include rubber polymers that are impact-resistant additives such as diene rubbers such as natural rubber, polybutadiene rubber, polyisoprene rubber, acrylonitrile / butadiene copolymer rubber; Butadiene copolymer rubber, styrene / isoprene copolymer rubber, styrene / butadiene / isoprene terpolymer rubber; hydrogenated diene rubber; ethylene / α-olefin copolymer such as ethylene / propylene copolymer , Saturated polyolefin rubbers such as propylene / other α-olefin copolymers; ethylene / propylene / diene copolymers, α-olefin / diene copolymers, isobutylene / isoprene copolymers, isobutylene / diene copolymers, etc. Α-Olefin / Diene Polymer Rubber; Urethane Rubber, Silica Special rubbers such as rubber, polyether rubber, acrylic rubber, propylene oxide rubber and ethylene / acrylic rubber; thermoplastic elastomers such as styrene / butadiene / styrene block copolymer rubber and styrene / isoprene / styrene block copolymer rubber; Examples thereof include hydrogenated thermoplastic elastomers; urethane-based thermoplastic elastomers; polyamide-based thermoplastic elastomers; 1,2-polybutadiene-based thermoplastic elastomers. The blending amount is appropriately selected within a range not impairing the object of the present invention, but is usually about 3 to 30 parts by weight, preferably 5 to 20 parts by weight with respect to 100 parts by weight of the β-pinene polymer. Range.

  Thus, in order to obtain the target food packaging body, a β-pinene polymer composition obtained by blending various compounding agents with a predetermined β-pinene polymer is a characteristic of such a β-pinene polymer. Is sufficiently contained, the β-pinene polymer is contained in a proportion of at least 70% by mass or more. Among them, the content of the β-pinene polymer is desirably 80% by mass or more.

By the way, as a molding method of a food packaging body using the β-pinene polymer according to the present invention, conventionally known various molding methods can be appropriately selected. For example, an injection molding method, an extrusion molding method, Examples include extrusion blow molding, injection blow molding, multilayer blow molding, connection blow molding, double wall blow molding, stretch blow molding, vacuum molding, rotational molding, and solution casting. By adopting these molding methods, food packages such as films, sheets, tubes and bottles are molded. For example, it is molded as follows. In addition, in the case of being formed as a sheet or film, the thickness is appropriately selected according to the purpose, but generally a thickness of about 5 to 1000 μm, preferably about 10 to 500 μm is adopted. .
(1) A stretched sheet or film obtained by stretching a sheet or film in a uniaxial or biaxial direction, or by stretching in a biaxial direction and heat treatment;
(2) Rolled sheet or film by rolling a sheet or film;
(3) A tray cup-shaped container obtained by subjecting a sheet or film or the like to vacuum forming, pressure forming, vacuum pressure forming, etc.
(4) Bottles and cup-shaped containers by stretch blow molding from pipes.

  In addition, the food packaging object of the present invention can be configured as a single layer of β-pinene polymer according to the present invention, but is generally configured in a multilayer structure with other thermoplastic resins. It will be. And in such a multilayer laminated structure, one layer or two layers or more are constituted by the β-pinene polymer layer according to the present invention, while the remaining layers are formed using an appropriate resin material. However, the provision of a gas barrier layer having an excellent oxygen barrier property as one of the remaining layers is effective in enhancing the usefulness of the food package according to the present invention. In addition, the thickness of the layer which bears such a gas barrier property will be normally selected from the range of about 5-250 micrometers, Preferably it is 10-100 micrometers. In addition, as the other thermoplastic resin that gives the multilayer inner and outer layers, any one is adopted and is not particularly limited, but uses and required performance such as moisture permeability, heat resistance, heat sealability, and transparency. By selecting the inner and outer layer materials in consideration of the above, an excellent packaging material can be obtained.

Here, as the gas barrier layer, the oxygen permeability when converted to a film thickness of 20 μm under a condition of 20 ° C. and 65% RH (relative humidity) is usually 1.0 cc · 20 μm / m ² · day ·. An oxygen barrier layer of atm or less is used, and generally, various known oxygen barrier layers can be selected and laminated. In addition, as a thermoplastic resin which provides such a layer having oxygen barrier properties, all known resins can be used. For example, ethylene-vinyl alcohol copolymer, polyamide, polyvinylidene chloride resin, polyvinyl alcohol, fluorine Although resin etc. are mentioned, it is preferable to use the resin which does not contain chlorine at the time of incineration disposal, and does not contain chlorine. Among them, particularly preferable oxygen barrier resin is an ethylene-vinyl acetate copolymer having an ethylene content of 20 to 60 mol%, particularly 25 to 50 mol%, and a saponification degree of 96 mol% or more, particularly 99 mol. The saponified copolymer obtained by saponification to be at least% is mentioned. Other preferable oxygen barrier resins include polyamides having 5 to 50, especially 6 to 20, amide groups per 100 carbons, such as nylon 6, nylon 6,6, nylon 6 and the like. / 6,6 copolymer, metaxylylene adipamide (MXD6 nylon), nylon 6,10, nylon 11, nylon 12, nylon 13, and polyester resin molded body with oxygen barrier layer made of inorganic material laminated Body, starch / polyacrylic acid composition, polyvinyl alcohol / clay composition, and the like.

  Other thermoplastic resins used to form the inner and outer layers include polyamide resins such as nylon 6, nylon 66, and nylon 12; polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, and co-polymers thereof. Polyester resins such as polymers; polypropylene, radiation-crosslinked polypropylene, polyethylene, ethylene-vinyl acetate copolymers, ethylene-methacrylic acid copolymers, ethylene-acrylic acid ester copolymers, ethylene-methacrylic acid ester copolymers Polyolefin resins such as polymers; polystyrene resins, polyvinyl chloride resins, acrylic resins, polyvinylidene chloride resins, polyacetal resins, polycarbonate resins, and the like. These resins can be used alone or in layers. Used And thus. In particular, from the viewpoint of impact resistance, heat resistance, and drop strength, it is preferable to use a polyamide resin, a polyester resin, or a polyolefin resin.

  The multilayer structure described above can be manufactured by various known lamination methods such as coextrusion method, dry lamination method, sand lamination method, extrusion lamination method, coextrusion lamination method, solution coating method, etc. I can do it. Therefore, the co-extrusion method is a method in which a thermoplastic resin, an adhesive resin, other thermoplastic resins, etc. are laminated in a molten state from an extruder and formed into a film form from a die outlet. Furthermore, if necessary, stretching, thermoforming, and the like are performed.

  The food package according to the present invention thus obtained has excellent mechanical strength, heat resistance, transparency, water vapor barrier property, does not generate harmful gas during incineration, and is lightweight, so it can be used for vegetables, fruits, meat, fish. It can be used widely and advantageously as a packaging material for many foods such as fresh foods such as frozen foods, cereals, confectionery, and bread.

  Hereinafter, some examples of the present invention will be shown and the present invention will be more specifically clarified, but the present invention is not limited by the description of such examples. It goes without saying. In addition to the following examples, the present invention can be subjected to various changes, corrections, improvements and the like based on the knowledge of those skilled in the art without departing from the spirit of the present invention. Should be understood.

  First, as a food packaging material according to the present invention, a hydrogenated β-pinene polymer was synthesized as follows.

  About the fully dried glass flask with a cock, after the inside was sufficiently substituted with nitrogen, dehydrated N-hexane: 184 parts by mass, dehydrated methylene chloride: 210 parts by mass, and dehydrated diethyl ether : 0.5 part by mass was added and cooled to -78 ° C. While stirring the mixture at -78 ° C, hexane solution of ethylaluminum dichloride (concentration: 1.0 mol / L): 7.2 parts by mass was further added. Next, in a state where the inside of the flask was kept at −78 ° C., when 3.0 parts by mass of a hexane solution of p-dicumulyl chloride (concentration: 0.1 mol / L) was added, the color changed to red amber. Thereafter, 60 parts by mass of β-pinene that was immediately purified by distillation was added to the flask over 1 hour. The solution gradually became dark blue and the viscosity of the solution increased. After the addition of β-pinene, 30 parts by mass of methanol was added to terminate the reaction. In the flask, an aqueous solution obtained by adding 5 parts by mass of citric acid to 100 parts by mass of distilled water is added and stirred for 5 minutes. Then, the aqueous layer is extracted, and the aqueous layer becomes neutral by adding distilled water. Until the aluminum compound was removed. The obtained organic layer was reprecipitated in a mixed solvent of methanol / acetone (50/50 vol%): 5000 parts by mass and then sufficiently dried to obtain 60 parts by mass of β-pinene polymer (A1). . The obtained β-pinene polymer (A1) had a weight average molecular weight of 116,000, a number average molecular weight of 51,000, and a glass transition temperature of 95 ° C.

By adding 70 parts by mass of cyclohexane and 30 parts by mass of the β-pinene polymer (A1) obtained as described above to a pressure vessel equipped with a stirrer substituted with nitrogen, and stirring the mixture, a β-pinene polymer ( A1) was completely dissolved. Next, 5% palladium-supported alumina (manufactured by NE ChemCat) as a hydrogenation catalyst: 30 parts by mass was added and sufficiently dispersed by stirring, and then the inside of the pressure vessel was sufficiently replaced with hydrogen. While stirring at 1000 rpm, the mixture was reacted at 100 ° C. and hydrogen pressure of 40 kgf / cm ² for 6 hours, and then returned to normal pressure. The reaction solution was diluted by adding 200 parts by mass of cyclohexane, filtered through a 0.5 μm Teflon (registered trademark) filter to separate and remove the catalyst, and then a mixed solvent of methanol / acetone (50/50 vol%): 5000 After re-precipitation in parts by mass, it was sufficiently dried to obtain 29 parts by mass of β-pinene polymer hydrogenated product (H1). When the hydrogenation rate of the obtained β-pinene polymer hydrogenated product (H1) was determined from ¹ H-NMR, it was 99.9%, the weight average molecular weight was 112,000, and the number average molecular weight was 50,800. The glass transition temperature was 130 ° C. and the specific gravity was 0.930.

  Thereafter, 0.1 part of 2- (5-methyl-2hydroxyphenyl) benzotriazole, which is an ultraviolet absorber, is added to 100 parts by mass of the thus obtained high molecular weight β-pinene polymer hydrogenated product (H1). After mixing a mass part and 0.1 mass part of Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) which is a phenolic antioxidant, using a Henschel mixer, melt-kneading using an extruder, A pellet-like β-pinene polymer hydrogenated composition (M1) was obtained.

  In addition, about the material obtained at each above-mentioned process, and the material manufactured at the following process, the physical-property measurement was performed as follows.

-Molecular weight-
The number average molecular weight and the weight average molecular weight are both determined in terms of polystyrene based on measurement by gel permeation chromatography (GPC). Here, HLC-8020 (product number) manufactured by Tosoh Co., Ltd. is used as the GPC device, and TSKgel / GMH-M manufactured by Tosoh Co., Ltd. and one G2000H are connected in series as the column. Using.

-Hydrogenation rate-
^{From the 1} H-NMR spectrum, the hydrogenation rate {([number of hydrogenated olefinic double bonds] / [hydrogen] is determined by the reduction rate (%) of olefinic double bond protons (4 to 6 ppm) of the raw material resin. The number of olefinic double bonds in the polymer before addition]) × 100 (%)} was determined.

-Glass transition temperature (Tg)-
It measured by the differential scanning calorimetry (DSC) using the sample which fully dried and removed the solvent. First, a sample is heated from 25 ° C. to 200 ° C. at a rate of temperature increase of 10 ° C./min under a stream of nitrogen of 100 ml / min to obtain a DSC curve. Next, using the obtained DSC curve, as shown in FIG. 1, a parallel line E passing through the intersection of the center tangent B and the base line C before the transition and parallel to the temperature axis, and the center tangent B A parallel line F passing through the intersection of the base line D after the transition and parallel to the temperature axis is drawn. In this specification, the temperature A at the intersection of the parallel line G that bisects the two parallel lines E and F and the DSC curve is defined as the glass transition temperature (Tg). In addition, here, DSC30 (product number) manufactured by METTLER TOLEDO Co., Ltd. was used as a measuring device.

-Total light transmittance-
About the obtained film-form food packaging body, it measured based on JIS-K-7361-1 using HR-100 (product number) by Murakami Color Research Laboratory.

-Water absorption rate-
A press-formed plate having a length of 140 mm, a width of 60 mm, and a thickness of 1.0 mm was placed in an atmosphere of 60 ° C. and 90% RH for 10 days, and the weight ratio increased from the initial weight. Was the water absorption. The arithmetic expression is as follows.
Water absorption (%) = weight increase x 100 / initial weight

-Moisture resistance-
An endurance test for 1000 hours was performed under the conditions of 80 ° C. and 90% RH, and the appearance change was visually observed and evaluated according to the following criteria.
○: No change visually.
X: Cloudiness or deformation is observed.

-Solvent resistance test-
The test pieces were immersed in a pH 9 sodium carbonate aqueous solution, pH 4 hydrochloric acid, and ethanol for 48 hours, respectively, and the appearance was observed and evaluated according to the following criteria.
○: No change in appearance in any solvent, no change in turbidity and total light transmittance.
X: Appearance changes with any solvent. Turbidity and total light transmittance decreased.

-Oxygen permeability-
OXY-TRAN100 (manufactured by Modern Control) was used and measured under the conditions of 20 ° C. and 65% RH to obtain oxygen permeability (cc / m ² · day · atm).

-Water vapor permeability-
Using “MOCON PERMATRAN-3 / 33” manufactured by Modern Control Co., Ltd., water vapor permeability was measured under the conditions of temperature: 40 ° C. and humidity: 90% RH. The water vapor permeability (unit: g · 20 μm / m ² · day) when converted to a film thickness of 20 μm was determined and evaluated based on the following criteria.
○: Water vapor transmission rate <20 g · 20 μm / m ² · day
×: Water vapor permeability ≧ 20 g · 20 μm / m ² · day

Example 1
The pellets of β-pinene polymer hydrogenated composition (M1) (glass transition temperature: 130 ° C.) obtained above were dried at 90 ° C. for 4 hours using a hot air dryer. Next, this pellet was melt-extruded at 260 ° C. using a screw hanger die having a screw diameter of 20 mm and a 150 mm-width coated hanger die, and then the extruded sheet-like β-pinene. The polymer hydrogenated composition (M1) was cooled by passing through three cooling rolls (diameter: 100 mm, roll temperature: 120 ° C.) to obtain an extruded film having a width of about 100 mm and a thickness of 50 μm.

-Comparative Example 1-
Pellets of alicyclic polyolefin resin (ZEONOR 1020R manufactured by Nippon Zeon Co., Ltd., glass transition temperature: 100 ° C.) were dried at 80 ° C. for 4 hours using a hot air dryer. Next, this pellet was melt-extruded at 260 ° C. using the same apparatus as in Example 1, and then the extruded sheet-like alicyclic polyolefin-based resin was converted into three cooling rolls (diameter: 100 mm, roll (Temperature: 90 ° C.) and cooled to obtain an extruded film having a width of about 100 mm and a thickness of 50 μm.

-Comparative Example 2-
Pellets of polylactic acid (Lacia H100 manufactured by Mitsui Chemicals, Inc., glass transition temperature: 60 ° C.) were dried at 50 ° C. for 4 hours using a hot air dryer. Next, this pellet was melt-extruded at 180 ° C. using the same apparatus as in Example 1, and then the extruded sheet-like polylactic acid resin was cooled to three cooling rolls (diameter: 100 mm, roll temperature: 90). And an extruded film having a width of about 100 mm and a thickness of 50 μm was obtained.

  The characteristics of the three types of films obtained in Example 1 and Comparative Examples 1 and 2 were measured according to the measurement method described above, and the results are shown in Table 1 below.

-Example 2-
Using the β-pinene polymer hydrogenated composition (M1) (glass transition temperature: 130 ° C.) obtained above as an inner and outer layer material, EVOH (“Eval EP-G110” manufactured by Kuraray Co., Ltd.): Melt flow rate 14 g / 10 minutes (190 ° C., 2.16 kg load), melting point: 160 ° C. as the center layer material, and maleic anhydride modified polypropylene (AD) {“Admer QF500” manufactured by Mitsui Petrochemical Co., Ltd., MI = 5.3 g / 10 minutes (230 ° C., 2160 g load)} as an adhesive, in those laminated structures, extruded from a co-extruder equipped with a T-die, 3 types 5 layers (M1 / AD / EVOH / AD / M1) = 200 μm / 50 μm / 100 μm / 50 μm / 200 μm), and a thermoformed sheet having a total thickness of 1000 μm was obtained. The obtained thermoformed sheet had a good oxygen permeability of 0.2 cc / m ² · day · atm. Further, the water vapor permeability was as good as 0.8 g / m ² · day.

  As is apparent from the results of the examples and comparative examples, the molded body using the hydrogenated β-pinene polymer according to the present invention has excellent transparency, high heat resistance, low water absorption, light resistance and It turns out that the food packaging body excellent in solvent resistance was obtained. Moreover, although the comparative example 1 is excellent in transparency and solvent resistance, it is heavy because specific gravity is large, and it turns out that light resistance is not enough. Furthermore, although the polylactic acid of the comparative example 2 is a carbon neutral material, it turns out that specific gravity is large, heat resistance is low, and moisture resistance, light resistance, and solvent resistance are not enough.

It is explanatory drawing which shows the method of calculating | requiring the glass transition temperature in an Example from a DSC curve.

Claims (4)

  A food packaging body comprising at least one layer containing at least 70% by mass of a β-pinene polymer having a glass transition temperature of 80 ° C. or more and a specific gravity of 0.85 or more and less than 1.0.   The β-pinene polymer is hydrogenated, ([number of hydrogenated olefinic double bonds] / [number of olefinic double bonds in the polymer before hydrogenation]) The value of x100 is 95% or more, The food packaging body of Claim 1 characterized by the above-mentioned. The food according to claim 1, further comprising a gas barrier layer having an oxygen permeability of 1.0 cc / m ² · day · atm or less under the conditions of 20 ° C. and 65% RH. Packaging body. The food packaging body according to any one of claims 1 to 3, wherein at least one layer selected from a polyester layer, a polyamide layer, and a polyolefin layer is further laminated.

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