JP4798820B2 - Lid material - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas barrier lid material useful as a lid material for food containers such as miso, milk pudding, yogurt, cheese, cheesecake, raw milk, and bavaroa.
[0002]
[Prior art]
Food container lids such as miso, milk pudding, yogurt, cheese, cheesecake, raw milk, and bavaria are usually required to have a function of preventing the transmission of odor, water vapor, oxygen, and visible light. In order to meet this requirement, in general, (1) From a laminate in which each layer of an aluminum-deposited biaxially stretched polyethylene terephthalate film / polyethylene film adhesive layer / polyethylene heat-sealable film is provided on the back surface of wax-coated printing paper. (2) Laminate with wax-coated printing paper provided with aluminum foil on the back and heat-sealable resin layers such as ethylene / acrylic acid copolymer and ethylene / vinyl acetate copolymer on the back Opaque lids made of objects are used to form these food containers.
[0003]
In general, the food container is filled with contents such as miso, milk pudding, yogurt, etc., and then inspected for foreign matter such as metal powder in the contents, and then the lid is opened on the opening of the container. The material is heat sealed and shipped or stored. However, since the inspection during opening gives the opportunity for dust and foreign matter to enter the container, it is possible to provide a lid that can be inspected for metal powder contamination after filling and heat-sealing the opening. Desired from the market.
Moreover, the conventional lid | cover material had the fault which the aluminum foil remained as burnt waste after incineration, and the process and time were required for the process.
[0004]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to solve these problems of the prior art.
That is, the present invention provides a cover material that can be subjected to metal inspection and the like and can be completely burned or regenerated after use even after the contents are filled and the opening is heat sealed with the cover material. It is a problem to be solved.
[0005]
[Means for Solving the Problems]
  As a result of intensive studies to solve these problems, the present inventors have found that the intended purpose can be achieved by using a cover material having a specific configuration and physical properties, and provides the present invention. It came to do.
  That is, in the first invention of the present invention, the heat-sealable resin adhesive layer (IV) is laminated on one surface of the microporous resin stretched film base layer (I) having an opacity (JIS P-8138) of 80% or more. The other surface is provided with an inorganic oxide thin film layer (III) which is a silicon oxide thin film layer or an amorphous aluminum oxide thin film layer.By vapor depositionThe provided polyethylene terephthalate resin film layer (II) is laminated so as to have the inorganic oxide thin film layer (III) between the stretched microporous resin film base layer (I) and the polyethylene terephthalate resin film layer (II). A laminate having a layer structure, wherein the moisture permeability (JIS Z-0208) of the laminate is 5 g / m.²-Less than 24 hr, oxygen permeability (JIS Z-1707) is 5 cc / m²-It is a lid | cover material characterized by being 24hr * atm or less.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the structure, material, and embodiment of the lid member of the present invention will be described in detail. <Structure of the lid>
  The structure of the lid isGas barrier resin film layer (II) / inorganic oxide thin film layer (III) / laminated porous film base layer (I) having an opacity of 80% or more / heat sealable resin adhesive layer (IV) Specifically, it is a laminate as shown in the enlarged cross-sectional view of the lid member of FIG.
  The laminate has a moisture permeability (JIS Z-0208) of 5 g / m.²-24 hr or less, and oxygen permeability (JIS Z-1707) is 5 cc / m²-The physical property is 24 hr · atm or less.
  FIG.In the figure, I is a stretched microporous resin film, II is a gas barrier resin film layer, III is an inorganic oxide thin film layer, IV is a heat-sealable resin layer, and P is printing.
[0008]
<Layer structure of laminate>
(1) Microporous resin stretched film base layer (I)
The stretched microporous resin film (I) has a function of reducing the light transmittance as well as facilitating identification of printing by giving the lid material a low strength and making it opaque. The opacity (JIS P-8138) is preferably 80% or more, more preferably 85 to 100%. As a microporous resin stretched film, the three films described below can be illustrated, for example.
Examples of the first stretched microporous resin film include a biaxially stretched thermoplastic resin film having microporosity containing an inorganic fine powder or an organic filler in an amount of 8 to 65% by weight (Japanese Patent Publication Akira). 54-31032, US Pat. No. 3,775,521, US Pat. No. 4,191,719, US Pat. No. 4,377,616, US Pat. No. 4,560,614 Issue description).
[0009]
As the second microporous resin stretched film, a uniaxially or biaxially stretched thermoplastic film containing 0 to 40% by weight of white inorganic fine powder is used as a core layer, and white inorganic fine powder is coated on both sides or one side of the core layer. Examples thereof include synthetic paper provided with a uniaxially stretched film of a thermoplastic resin containing 10 to 65% by weight as a paper-like layer (Japanese Patent Publication Nos. 46-40794, 57-149363, 57). No. 181829).
[0010]
Even though this synthetic paper has a two-layer structure, it has a three-layer structure in which a paper-like layer of a uniaxially stretched film exists on the front and back surfaces of the core layer (Japanese Patent Publication No. 46-40794, US Pat. No. 4,318,950). Even in such cases, a synthetic paper having three to seven layers in which another resin film layer is present between the paper layer and the core layer (Japanese Patent Publication Nos. 50-29738, 57-149363, 56-56). 126155, JP-A-57-181829, US Pat. No. 4,472,227).
Also, on the back of these synthetic papers, propylene / ethylene copolymer, metal salt of ethylene / (meth) acrylic acid copolymer (Na, Li, Zn, K), chlorinated polyethylene, ethylene / vinyl acetate copolymer, etc. Three or more synthetic papers provided with a heat seal layer (IV) made of a resin having a lower melting point than the resin of the base layer (I) may be used (Japanese Patent Publication No. 3-13973).
[0011]
Particularly preferred microporous resin stretched film base layer (I) is a uniaxially stretched film or a biaxially stretched film of a thermoplastic resin film containing 0 to 40% by weight of white inorganic fine powder and / or organic filler. A) and a laminate in which a uniaxially stretched film of a thermoplastic resin film containing 0 to 65% by weight of a white inorganic fine powder and / or an organic filler is provided on both sides of the core layer as front and back layers (B, B ′). It is a stretched film.
As a method for producing such a three-layer synthetic paper, for example, a thermoplastic resin film containing 0 to 40% by weight, preferably 8 to 25% by weight of inorganic fine powder and / or organic filler is used. The film is stretched in one direction at a temperature lower than the melting point, and 0 to 65% by weight, preferably 3 to 65% by weight, more preferably 10 to 65% by weight of inorganic fine powder and / or organic filler on both sides of the obtained uniaxially stretched film. A method of laminating a molten film of thermoplastic resin containing wt% and then stretching the laminated film in a direction perpendicular to the above-mentioned direction can be mentioned. The synthetic paper produced by this method is a laminated structure in which the paper layer is oriented in a uniaxial direction and has many fine voids, and the core layer is oriented in a biaxial direction.
[0012]
As the third microporous resin stretched film, a transparent thermoplastic resin having a wall thickness of 0.1 to 20 μm and further containing no inorganic fine powder on the paper layer side of the second microporous resin stretched film. Examples include synthetic paper provided with a laminate layer (Japanese Patent Publication No. 4-60437, Japanese Patent Publication No. 1-60411, Japanese Patent Laid-Open No. 61-3748, US Pat. No. 4,663,216). . The synthetic paper can be printed with high gloss.
[0013]
Specifically, a biaxially stretched film of thermoplastic resin is used as a core layer, and a multilayer film having a surface layer and a back layer made of a uniaxially stretched thermoplastic resin containing 8 to 65% by weight of inorganic fine powder is supported. A synthetic paper provided with a transparent film layer of a thermoplastic resin containing no inorganic fine powder on the surface layer side of this support, and further provided with a primer coating layer having an antistatic function (Japanese Patent Laid-Open No. 61-3748) Gazette) or a biaxially stretched film of a thermoplastic resin film as a core layer, and a uniaxially stretched film of a thermoplastic resin containing an inorganic fine powder in a proportion of 8 to 65% by weight on at least one surface of the core layer. A synthetic paper provided with a laminate of a paper layer and a surface layer made of a uniaxially stretched film of a thermoplastic resin film, wherein the thickness (t) of the surface layer is a paper layer A synthetic paper (Japanese Patent Publication No. 1-60411) made of a multilayer resin film, which satisfies the following formula (2) when the average particle diameter of the existing inorganic fine powder is (R), is exemplified. be able to.
[Formula 2]
R ≧ t ≧ 0.1 × R (2)
This multi-layered synthetic paper may also be provided with a heat-sealable resin layer (IV) on the back surface in the same manner as the second microporous resin stretched film.
[0014]
These microporous resin stretched films are microporous synthetic paper made of a stretched resin film having fine voids inside the film. The opacity (JIS P-8138) is preferably 80% or more, more preferably 85% or more, and the wall thickness is preferably 30 to 300 μm, more preferably 50 to 150 μm. Moreover, the porosity calculated by the following formula (1) is preferably 10 to 60%, more preferably 15 to 45%. Ρ in equation (1)₀Represents the true density of the support, ρ₁Represents the density of the support (JIS P-8118), but the true density is approximately equal to the density before stretching unless the material before stretching contains a large amount of air.
[0015]
[Formula 3]
[0016]
Examples of the thermoplastic resin used as the material for the synthetic paper include polyolefin resins such as high-density polyethylene, polypropylene, and poly (4-methyl-1-pentene), polyamide, polyethylene terephthalate, polybutylene terephthalate, and mixtures thereof. be able to. Among these, polypropylene and high density polyethylene are preferable from the viewpoint of water resistance and chemical resistance. When polypropylene is used for the core layer, 3 to 25% by weight of a thermoplastic resin having a melting point lower than that of polypropylene, such as polyethylene, polystyrene, ethylene / vinyl acetate copolymer, etc. is blended in order to improve stretchability. preferable.
[0017]
As the inorganic fine powder, for example, calcium carbonate, calcined clay, silica, diatomaceous earth, talc, titanium oxide, barium sulfate and the like can be used. The particle size is preferably 0.03 to 7 μm.
As the organic filler, it is preferable to select a filler made of a resin different from the thermoplastic resin as the main component. For example, when the thermoplastic resin film is a polyolefin resin film, polymers such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, nylon-6, nylon-6,6, cyclic olefin, polystyrene, polymethacrylate, etc. are used as the organic filler. And what has melting | fusing point (for example, 170-300 degreeC) higher than melting | fusing point of polyolefin resin or glass transition temperature (for example, 170-280 degreeC) can be used.
[0018]
The stretching ratio is preferably 4 to 10 times in both the longitudinal and transverse directions, and the stretching temperature is 130 to 162 ° C. when the resin is a propylene homopolymer (melting point 164 to 167 ° C.), and high density polyethylene (melting point 123 to 134 ° C.). Is 110 to 120 ° C. and polyethylene terephthalate (melting point 246 to 252 ° C.) is preferably 104 to 120 ° C. The stretching speed is preferably 50 to 350 m / min.
The thickness of the microporous resin stretched film base layer (I) is preferably 30 to 300 μm, more preferably 40 to 100 μm.
[0019]
(2) Heat-sealable resin adhesive layer (IV)
The heat-sealable resin adhesive layer is formed to melt and bond the lid material to the food container by heating.
A heat-sensitive adhesive resin is used for the heat-sealable resin adhesive layer. Examples of the heat-sensitive adhesive resin include ethylene / acrylic acid copolymer, ethylene / vinyl acetate copolymer, low density polyethylene, metal salt of ethylene / (meth) acrylic acid copolymer (so-called Surlyn; trade name), chlorine The thing of melting | fusing point of 60-135 degreeC, such as chlorinated polyethylene and chlorinated polypropylene, can be illustrated.
These can be formed, for example, by applying a resin solution in which a heat-sensitive adhesive resin is dissolved or dispersed in an organic solvent such as toluene, xylene, or tetralin, and then drying.
The thickness of the heat-sealable resin adhesive layer (IV) is preferably 1 to 50 μm, more preferably 2 to 40 μm.
[0020]
(3) Gas barrier resin film layer (II)
The gas barrier resin film layer is formed in order to significantly reduce the permeability of water vapor, oxygen, etc., and a gas barrier resin is used.
Gas barrier resins include saturated polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, polyamides such as nylon 6, nylon 12 and nylon 6,6, aromatic polycarbonate, polyvinylidene chloride, ethylene-vinyl alcohol copolymer Moisture permeability such as coalescence (JIS Z-0208) is 100g / m²-24 hr or less, preferably 50 g / m²・ 24hr or less, oxygen permeability (JIS Z-1707) is 300cc / m²· 24 hr · atm or less, preferably 200 cc / m²・ Use 24hr · atm or less.
The gas barrier resin film layer may or may not be stretched. The thickness of the gas barrier resin film layer (II) is preferably 6 to 40 μm, more preferably 8 to 20 μm.
[0021]
(4) Inorganic oxide thin film (III)
In order to further improve the gas barrier property of the lid, an inorganic oxide thin film (III) is formed on the surface of the gas barrier resin film layer (II).
For inorganic oxide thin film, amorphous Al₂O_Three, SiOx, SnOx, ZnOx, IrOx (x is a number of 1 to 2) or the like can be used. Among these inorganic oxides, amorphous Al₂O_ThreeSiOx is preferable in terms of transparency and workability, and SiOx is preferable in terms of gas barrier properties. The thickness of these thin films is limited by transparency, vapor deposition rate, gas barrier properties, film winding properties, and the like, and is preferably 5 to 600 nm, more preferably 20 to 500 nm. If it is thinner than 5 nm, the gas barrier property is insufficient, and if it is thicker than 600 nm, the transparency tends to deteriorate, and the inorganic oxide thin film itself tends to be cracked or peeled off. The inorganic oxide thin film preferably has a light transmittance of 75% or more and is transparent.
[0022]
As a vapor deposition method for forming the inorganic oxide thin film, the molded product is vacuumed (1 × 10 6) in a high frequency induction heating type vapor deposition machine.^-6~ 1x10^-3Torr) (see Japanese Patent Publication No. Sho 53-12953, Japanese Patent Laid-Open Publication No. Sho 62-101428), an organic silicon compound that has been evacuated in advance and volatilized in a vacuum deposition machine, oxygen, and inertness A method in which a gas flow containing gas is generated by magnetron glow discharge to deposit SiOx on a molded product in the vapor deposition machine (Japanese Patent Laid-Open No. 64-87777, US Pat. No. 4,557,946, US Patent No. 4,599,678) and the like. The thin film forming method is classified as an ion plating method, a high-frequency plasma CVD method, an electron beam (EB) vapor deposition method, and a sputtering method in Industrial Materials Vol. 38, No. 14, pages 104-105 published in November 1990. The principle is introduced.
[0023]
The determination of the crystallinity or amorphousness of the aluminum oxide can be easily measured with a normal X-ray diffractometer using Cu Kα rays. For example, crystalline α-Al₂O_ThreeIs included, a clear diffraction peak appears at a position where the diffraction angle 2θ is 43.39 degrees, 57.56 degrees, or the like. β-Al₂O_ThreeIn this case, a position diffraction peak having a diffraction angle 2θ of 66.65 degrees or 33.43 degrees appears. The crystal grain size can also be measured from the half-value width of these diffraction peaks. In addition, γ-Al₂O_Three, Δ-Al₂O_ThreeFor other crystalline aluminum, etc., a unique diffraction peak can be measured in the same manner. In the case of amorphous aluminum oxide, a specific diffraction peak is not measured by the X-ray diffractometer. The non-crystalline aluminum oxide referred to here is one in which specific diffraction is not observed by X-ray diffraction.
[0024]
(5) Adhesive layer
Depending on the type of the gas barrier resin film layer (II), the adhesion between the film layer (II) and the inorganic oxide thin film (III) may be insufficient. In such a case, the primer layer (Ia) is formed by applying the primer (adhesive) (Ia) between the gas barrier resin film layer (II) and the inorganic oxide thin film (III). be able to. Examples of the primer include a polyurethane-based primer such as polyester polyol / polyisocyanate and polyether polyol / polyisocyanate. Primer coating amount is 0.5-5 g / m²(Solid content) is common.
[0025]
Lamination (adhesion) of the microporous resin stretched film base layer (I) and the gas barrier resin film (II) is performed by using the gas barrier resin film as a filler when producing the microporous resin stretched film (I). A laminate of the microporous resin stretched film (I) and the gas barrier resin film (II) may be produced at the same time by coextrusion with the containing resin film, and both may be produced using the primer. May be adhered. The adhesive surface may be on the gas barrier resin film (II) side or on the inorganic oxide thin film (III) side.
[0026]
(6) Other layers
In addition to the above-mentioned microporous resin stretched film (I), primer layer (Ia), gas barrier resin film (II), inorganic oxide thin film (III), heat sealable resin film (IV) In order to contribute to the lid material to improve the rigidity, anti-tear property, and light impermeability of the lid material, a microporous resin stretched film base layer (I ) And the gas barrier resin film layer (II).
Further, a protective layer may be provided on the surface of the print (P) provided on the surface of the above-mentioned stretched microporous resin film (I), or an inorganic oxide thin film provided on the gas barrier resin film (II) ( When III) comes to the surface side, a protective layer may be provided on the surface of the inorganic oxide thin film (III).
[0027]
The lid used for the food container of the present invention has a moisture permeability (JIS Z-0208) of 5 g / m.²-24 hr or less, preferably 2 g / m²-24 hr or less, more preferably 1 g / m²-24 hr or less, oxygen permeability (JIS Z-1707) is 5 cc / m²・ 24hr ・ atm or less, preferably 2cc / m²・ 24 hr · atm or less, more preferably 1 cc / m²・ It is 24 hr · atm or less.
By satisfying these conditions, the contents can be prevented from being deteriorated and quality is lowered. Furthermore, in order to use for packaging of contents such as milk pudding, yogurt and the like that do not like incident light, it is necessary that the total light transmittance (JIS K-7105) of the lid is 5% or less.
[0028]
When the thickness of each layer is thin and the light shielding properties are insufficient, the back of the microporous resin stretched film (I) is shielded by black solid printing with a thickness of 1 to 5 μm by offset or gravure printing. A large amount of white filler such as titanium oxide whisker and titanium oxide fine particles is formed in the primer layer that forms a layer or adheres the microporous resin stretched film base layer (I) and the gas barrier resin film layer (II). (5 to 75% by weight) and 2 to 10 g / m of the primer adhesive.²It is also possible to form a shielding layer by a method such as coating, and to set the total light transmittance of the lid member to 5%.
The wall thickness of the lid member is 50 to 350 μm, preferably 80 to 150 μm, to give flexibility.
[0029]
【Example】
Hereinafter, the present invention will be described more specifically with reference to production examples and examples. The following materials, amounts used, ratios, operations, and the like can be appropriately changed unless exempted from the spirit of the present invention. Accordingly, the scope of the present invention is not limited by the following examples.
[Production Example 1]
Production of microporous resin stretched film
(1) Melt flow rate (MFR) 0.8 g / 10 min (ASTM D1238: 230 ° C., 2.16 kg load) propylene homopolymer (melting point: about 164 to 167 ° C.) 81% by weight, high density polyethylene 3% % And a composition (a) mixed with 16% by weight of calcium carbonate having an average particle size of 1.5 μm were kneaded in an extruder set at 270 ° C., then extruded into a sheet shape, further cooled by a cooling roll, A stretched sheet was obtained.
This sheet was heated again to 150 ° C., and then stretched 5 times in the machine direction using the peripheral speed difference of the roll group to obtain a 5 times longitudinally stretched film.
[0030]
(2) A composition (b) in which 54% by weight of a propylene homopolymer (melting point: about 164 to 167 ° C.) having an MFR of 4 g / 10 minutes and 46% by weight of calcium carbonate having an average particle diameter of 1.5 μm are mixed. After being kneaded at 210 ° C. by an extruder, the sheet was extruded into a sheet shape by a die and laminated on both surfaces of the 5-fold longitudinally stretched film obtained in the step (1) to obtain a laminated film having a three-layer structure. Next, this three-layer laminated film was cooled to 60 ° C., then heated again to about 155 ° C., stretched 7.5 times in the transverse direction using a tenter, and annealed at 165 ° C. Then, after cooling to 60 ° C. and performing corona discharge treatment on both sides, the ears are slit and the thickness of the three-layer structure (uniaxial stretching / biaxial stretching / uniaxial stretching) is 80 μm (B / A / B = 10 μm / 60 μm). / 10μm) laminated film, opacity 87%, porosity 31%, density 0.78 g / cm^Three  , Water vapor permeability (air permeability; temperature 40 ° C., relative humidity 90%) 3.4 g / m²・ 24hr, oxygen permeability 920cc / m²-A stretched resin film having 24 hr.atm and a total light transmittance of 14% was obtained.
[0031]
[Production Example 2]
Production of microporous resin stretched film
In the same manner as in Production Example 1, except that the die lip width is changed so that the thickness of each layer (B / A / B) is 15 μm / 30 μm / 15 μm (total thickness 60 μm). %, Porosity 33%, density 0.79 g / cm^ThreeWater vapor transmission rate 6.0g / m²・ 24hr, oxygen permeability 1,360cc / m²-A stretched resin film having 24 hr.atm and a total light transmittance of 21% was obtained.
[0032]
[Production Example 3]
Production of microporous resin stretched film
(1) A composition obtained by mixing 55% by weight of a propylene homopolymer having an MFR of 4 g / 10 min (melting point: about 164 to 167 ° C.) with 25% by weight of high-density polyethylene and 20% by weight of calcium carbonate having an average particle diameter of 1.5 μm. After kneading with an extruder set at 270 ° C., it was extruded into a sheet shape and further cooled with a cooling roll to obtain an unstretched sheet.
[0033]
(2) The sheet was heated again to 150 ° C., and then stretched 5 times in the longitudinal direction to obtain a 5 times longitudinally stretched film.
Next, the film was heated again to 155 ° C., stretched 7.5 times in the transverse direction using a tenter, and annealed at 165 ° C. Then, after cooling to 60 ° C. and corona discharge treatment on both sides, the ears were slit and the density was 0.88 g / cm.^ThreeOpacity 86%, wall thickness 60 μm, porosity 37%, water vapor transmission rate 7.2 g / m²・ 24hr, oxygen permeability 1,680cc / m²-A biaxially stretched film having 24 hr.atm and a total light transmittance of 23% was obtained.
[0034]
[Production Example 4]
Production of microporous resin stretched film
A mixture containing 70% by weight of a propylene homopolymer (melting point: about 164 to 167 ° C.) of 4 g / 10 min of MFR, 8% by weight of high-density polyethylene and 22% by weight of calcium carbonate having an average particle size of 1.5 μm is referred to as (A), and MFR 20 g / 10 min propylene homopolymer (melting point: about 164 to 167 ° C.) 40% by weight and a mixture containing 60% by weight of calcium carbonate having an average particle size of 1.5 μm as (B). The mixture was melt-kneaded at 0 ° C., laminated so as to have the mixture (A) on the core layer and the mixture (B) on both sides thereof, coextruded, and cooled by a cooling device to obtain an unstretched three-layered sheet. After heating this sheet to 135 ° C., a uniaxially stretched film stretched 5 times in the longitudinal direction was obtained.
[0035]
Further, corona discharge treatment was performed on both surfaces of the film to obtain a stretched film having a three-layer structure (uniaxial stretching / uniaxial stretching / uniaxial stretching). This film is a laminated film having a wall thickness of 80 μm (B / A / B = 10 μm / 60 μm / 10 μm), opacity of 87%, porosity of 29%, density of 0.85 g / cm.^Three, Water vapor transmission rate (air permeability; temperature 40 ° C., relative humidity 90%) 3.0 g / m²・ 24hr, oxygen permeability 920cc / m²It was 24 hr · atm and the total light transmittance was 16%.
[0036]
[Production Example 5]
  SiO₂Production of vapor deposition gas barrier film
  On one side of a 12 μm thick polyethylene terephthalate biaxially stretched film (stretched 3 times in the machine direction and 3 times in the transverse direction), an isocyanate compound (manufactured by Nippon Polyurethane Industry Co., Ltd.):"Coronate"(Registered trademark)L) and saturated polyester (manufactured by Toyobo Co., Ltd .:"Byron"(Registered trademark)300) was applied at a ratio of 50:50 and dried to form a resin layer having a thickness of about 0.1 μm.
  On the resin layer, 8 × 10^-FiveSiO of 99.9% purity by high frequency induction heating method under Torr vacuum₂Is evaporated by heating to a thickness of 100 nm of SiO.₂A film was formed. The resulting film has a water vapor permeability of 0.9 g / m.²・ 24hr, oxygen permeability is 0.5cc / m²• 24 hr · atm, total light transmittance was 80%.
[0037]
[Production Example 6]
SiO₂Production example of vapor deposition gas barrier film
The water vapor permeability was 0.7 g / m as in Production Example 5 except that the thickness of the silicon oxide thin film was 300 nm.²・ 24hr, oxygen permeability is 0.4cc / m²・ 24hr ・ atm, total light transmittance of 77% SiO₂A vapor-deposited polyethylene terephthalate biaxially stretched film was obtained.
[0038]
[Production Example 7]
  Production of amorphous aluminum oxide vapor deposited gas barrier film
  On one side of a 12 μm thick polyethylene terephthalate biaxially stretched film (stretch ratio of 3 times in the machine direction and 3 times in the transverse direction), an isocyanate compound (manufactured by Nippon Polyurethane Industry Co., Ltd .:"Coronate"(Registered trademark)L) and saturated polyester (manufactured by Toyobo Co., Ltd .:"Byron"(Registered trademark)300) was applied at a ratio of 50:50 and dried to form a resin layer having a thickness of about 0.1 μm.
  Next, on the resin layer, 8 × 10^-FiveAl with 99.9% purity by high frequency induction heating method under Torr vacuum₂O_ThreeWas evaporated by heating to form an amorphous aluminum oxide film having a thickness of 100 nm.
  This Al₂O_ThreeThe vapor-deposited polyethylene terephthalate biaxially stretched film has a water vapor transmission rate of 3 g / m.²・ 24hr, oxygen permeability 3cc / m²-It was 24 hr.atm and the total light transmittance 86%.
[0039]
[Production Example 8]
Production of amorphous aluminum oxide vapor deposited gas barrier film
Al₂O_ThreeThe water vapor transmission rate was 2 g / m as in Production Example 7 except that the thickness of the thin film was 500 nm.²・ 24hr, oxygen permeability 2cc / m²-An amorphous aluminum oxide-deposited polyethylene terephthalate biaxially stretched film having 24 hr.atm and a total light transmittance of 85% was obtained.
[0040]
[referenceExample 1]
  After offset printing was performed on the surface of the microporous stretched resin film having a thickness of 80 μm obtained in Production Example 1, a polyurethane-based primer (manufactured by Toyo Morton Co., Ltd .: BLS-2080A and BLS-) 2080B mixture; trade name: 4 g / m of an adhesive prepared by mixing 15 parts by weight of titanium oxide with 85 parts by weight²(Solid content) applied and SiO obtained in Production Example 5₂Bond the film side of the evaporated polyethylene terephthalate biaxially stretched film, SiO₂10 g / m of hot melt adhesive for coating (made by Hirodine Co., Ltd .: 7560 for extrusion coating; trade name) as a heat seal resin layer on the vapor deposition surface²After applying (solid content) and drying, a cover material having a thickness of about 106 μm was produced.
  This lid has an opacity of 98%, a total light transmittance of 2%, and a water vapor transmission rate of 0.2 g / m.²・ 24hr, oxygen permeability is 0.3cc / m²-It was 24 hr.atm.
[0041]
A cylindrical polypropylene miso container is filled with 200 g of miso, and this lid is placed with the printing surface facing up so that the heat seal resin layer is on the miso container side. A hot plate was heat sealed. It confirmed that the metal powder was not mixed with the metal detector from the outside of the obtained miso container.
This miso container was left in a temperature-controlled room with a relative humidity of 75% and a temperature of 25 ° C. for 3 months.
Next, the lid was opened, and the presence or absence of discoloration of the miso and the flavor were examined.
[0042]
[referenceExample 2]
  referenceIn Example 1, instead of the microporous resin stretched film obtained in Production Example 1, the thickness was about 86 μm in the same manner except that the microporous resin stretched film having a thickness of 60 μm obtained in Production Example 2 was used. Water vapor permeability 0.1g / m²・ 24hr, oxygen permeability 0.3cc / m²-A lid with 24 hr.atm, opacity of 89%, and total light transmittance of 5% was obtained.
  Next, a cylindrical polystyrene yogurt container is filled with 100 g of yogurt, and the lid is attached.referenceAfter heat-sealing and sealing in the same manner as in Example 1, it was confirmed that metal powder was not mixed from the outside of the obtained yogurt container with a metal detector.
  This was stored refrigerated at 5 ° C. for 2 weeks, the lid was opened, and the appearance and flavor of the yogurt were examined, but there was no change in the appearance or flavor of the yogurt.
[0043]
[referenceExample 3]
  referenceIn Example 1, instead of the stretched microporous resin film obtained in Production Example 1, the stretched microporous resin film having a thickness of 60 μm obtained in Production Example 3 was used, except that the thickness was about 87 μm. Water vapor permeability 0.2g / m²・ 24hr, oxygen permeability 0.4cc / m²-A lid with 24 hr.atm, opacity of 89%, and total light transmittance of 4% was obtained.
  Next, a cylindrical polypropylene cheese container is filled with 100 g of cheese, and a lid is formed.referenceAfter heat-sealing and sealing in the same manner as in Example 1, it was confirmed that metal powder was not mixed from the outside of the obtained cheese container with a metal detector.
  This was stored refrigerated at 5 ° C. for 3 weeks, then the lid was opened, and the appearance and flavor of the cheese were examined, but there was no change in the cheese appearance or flavor.
[0044]
[referenceExample 4]
  referenceIn Example 1, instead of the stretched microporous resin film obtained in Production Example 1, the stretched microporous resin film having a thickness of 80 μm obtained in Production Example 4 was used. 99%, total light transmittance 1%, water vapor transmission rate 0.2g / m²・ 24hr, Oxygen permeability 0.4cc / m²A lid material of 24 hr · atm was obtained.
  referenceIn the same manner as in Example 1, after filling 200 g of miso, heat-sealing the opening, and confirming from the outside of the container that metal powder is not mixed with a metal detector, a constant temperature of 75% relative humidity and a temperature of 25 ° C. Left in the room for 3 months.
  Next, the lid was opened and the miso was examined, but no change was found in the quality of the miso.
[0045]
[referenceExample 5]
  referenceIn Example 1, the SiO obtained in Production Example 5₂SiO obtained in Production Example 6 instead of vapor-deposited polyethylene terephthalate biaxially stretched film₂A lid with a thickness of about 108 μm was obtained in the same manner except that a vapor-deposited polyethylene terephthalate biaxially stretched film was used.
  This lid has an opacity of 99%, a total light transmittance of 1%, and a water vapor transmission rate of 0.1 g / m.²・ 24hr, oxygen permeability is 0.2cc / m²-It was 24 hr.atm.
  referenceIn the same manner as in Example 1, after filling 200 g of miso, heat-sealing the opening, and confirming from the outside of the container that metal powder is not mixed with a metal detector, a constant temperature of 75% relative humidity and a temperature of 25 ° C. Left in the room for 3 months.
  Next, the lid was opened and the miso was examined, but no change was found in the quality of the miso.
[0046]
[referenceExample 6]
  referenceIn Example 1, the SiO obtained in Production Example 5₂In the same manner, except that the aluminum oxide vapor-deposited polyethylene terephthalate biaxially stretched film obtained in Production Example 7 was used instead of the vapor-deposited polyethylene terephthalate biaxially stretched film. Rate 2%, water vapor permeability 3g / m²・ 24hr, oxygen permeability 2cc / m²A lid material of 24 hr · atm was obtained.
  referenceIn the same manner as in Example 1, after filling 200 g of miso, heat-sealing the opening, and confirming from the outside of the container that metal powder is not mixed with a metal detector, a constant temperature of 75% relative humidity and a temperature of 25 ° C. Left in the room for 3 months.
  Next, the lid was opened and the miso was examined, but no change was found in the quality of the miso.
[0047]
[referenceExample 7]
  referenceIn Example 1, the SiO obtained in Production Example 5₂The thickness is about 108 μm, the opacity is 99%, the total light transmittance is 2%, except that the aluminum oxide vapor-deposited polyethylene terephthalate biaxially stretched film obtained in Production Example 8 is used instead of the vapor-deposited polyethylene terephthalate biaxially stretched film. Water vapor permeability 2g / m²・ 24hr, oxygen permeability 1cc / m²A lid material of 24 hr · atm was obtained.
  referenceIn the same manner as in Example 1, after filling 200 g of miso, heat-sealing the opening, and confirming from the outside of the container that metal powder is not mixed with a metal detector, a constant temperature of 75% relative humidity and a temperature of 25 ° C. Left in the room for 3 months.
  Next, the lid was opened and the miso was examined, but no change was found in the quality of the miso.
[0048]
[referenceExample 8]
  SiO obtained in Production Example 6₂After performing offset printing on the film side surface of the vapor-deposited polyethylene terephthalate biaxially stretched film, 85 parts by weight of polyurethane-based primer (manufactured by Toyo Morton Co., Ltd .: mixture of BLS-2080A and BLS-2080B) is oxidized on the printed surface. 4 g / m of adhesive mixed with 15 parts by weight of titanium²(Solid content) is applied, and the microporous stretched resin film having a thickness of 80 μm obtained in Production Example 1 is adhered, and a hot-melt adhesive for coating (Hyrodine ( Co., Ltd .: Extrusion coating 7560) 10 g / m²After applying (solid content) and drying, a cover material having a thickness of about 107 μm was produced.
[0049]
  The cover material has an opacity of 98%, a total light transmittance of 1%, and a water vapor transmission rate of 0.1 g / m.²・ 24hr, oxygen permeability is 0.2cc / m²-It was 24 hr.atm.
  referenceIn the same manner as in Example 1, after filling 200 g of miso, heat-sealing the opening, and confirming from the outside of the container that metal powder is not mixed with a metal detector, a constant temperature of 75% relative humidity and a temperature of 25 ° C. Left in the room for 3 months.
  Then it was opened. There was no change in the quality of miso.
[0050]
【Example1]
  0.5 g / m each of polyurethane primer (manufactured by Toyo Morton Co., Ltd .: mixture of BLS-2080A and BLS-2080B) on both sides of the microporous resin stretched film having a thickness of 60 μm obtained in Production Example 3²(Solid content) was applied. Next, the SiO obtained in Production Example 6₂SiO of evaporated polyethylene terephthalate biaxially stretched film₂Gravure printing was performed on the vapor deposition side, and the printed surface was adhered to the microporous resin stretched film coated with the primer. A low-density polyethylene film having a thickness of 40 μm is adhered to the other surface (back surface) of the stretched microporous resin film to which the primer is applied, so that the thickness is about 114 μm, and the water vapor permeability is 0.2 g / m.²・ 24hr, oxygen permeability 0.4cc / m²-A lid with 24 hr.atm, opacity of 89%, and total light transmittance of 3% was obtained.
  referenceIn the same manner as in Example 2, 100 g of yogurt was filled, the opening was heat-sealed, and after confirming from the outside of the container that the metal powder was not mixed with a metal detector, this was refrigerated at 5 ° C. for 2 weeks. The lid was opened, and the appearance and flavor of the yogurt were examined, but there was no change in the appearance or flavor of the yogurt.
[0051]
【Example2]
  Example1SiO obtained in Production Example 6 ₂ In the same manner, except that the aluminum oxide vapor-deposited polyethylene terephthalate biaxially stretched film obtained in Production Example 8 was used instead of the vapor-deposited polyethylene terephthalate biaxially stretched film, the thickness was about 114 μm and the water vapor permeability was 0.3 g / m.²・ 24hr, oxygen permeability 0.6cc / m²-A lid with 24 hr.atm, opacity of 89%, and total light transmittance of 3% was obtained.
  referenceIn the same manner as in Example 2, 100 g of yogurt was filled, the opening was heat-sealed, and after confirming from the outside of the container that the metal powder was not mixed with a metal detector, this was refrigerated at 5 ° C. for 2 weeks. The lid was opened, and the appearance and flavor of the yogurt were examined, but there was no change in the appearance or flavor of the yogurt.
[0052]
【The invention's effect】
The lid material of the present invention is excellent in light blocking properties and gas barrier properties. Containers such as miso, yogurt, cheese, etc. formed by performing secondary processing using this lid material are metal of contents An inspection for the presence or absence of powder can be performed with a metal detector from the outside of the container.
[Brief description of the drawings]
FIG. 1 of the present inventionreferenceThe cross-sectional enlarged view of the cover material of an example is represented.
FIG. 2 is a cross-sectional view of a miso container using a lid according to an embodiment of the present invention.
FIG. 3 of the present inventionreferenceThe cross-sectional enlarged view of the cover material of Example 8 is represented.
FIG. 4 shows an embodiment of the present invention.1The cross-sectional enlarged view of the cover material of is represented.
[Explanation of symbols]
    I Microporous resin stretched film
  Ia Primer layer
  II Gas barrier resin film layer
III Inorganic oxide thin film layer
  IV Heat-sealable resin adhesive layer
    1 Lid
    A Core layer
    B surface layer
    B 'back layer
    P printing
    2 containers
    3 Miso
    4 Heat seal part

Claims (9)

A heat-sealable resin adhesive layer (IV) is laminated on one surface of a microporous resin stretched film base layer (I) having an opacity (JIS P-8138) of 80% or more, and a silicon oxide thin film layer on the other surface. Alternatively , the polyethylene terephthalate resin film layer (II) provided with the inorganic oxide thin film layer (III) which is an amorphous aluminum oxide thin film layer by vapor deposition is used as the microporous resin stretched film base layer (I) and the polyethylene terephthalate resin film. A laminate having a layer structure in which the inorganic oxide thin film layer (III) is laminated between the layers (II), and the moisture permeability (JIS Z-0208) of the laminate is 5 g / m ² · 24 hr or below, a lid member oxygen permeability (JIS Z-1707) is equal to or less than ^{5cc / m 2 · 24hr · atm} .   The thickness of the stretched microporous resin film base layer (I) is 30 to 300 μm, the thickness of the heat-sealable resin layer (IV) is 1 to 50 μm, and the thickness of the polyethylene terephthalate resin film layer (II) is 6 The lid material according to claim 1, wherein the thickness of the inorganic oxide thin film layer (III) is 5 to 600 nm and the total thickness of the lid material is 50 to 350 μm.   The cover material according to claim 1 or 2, wherein printing (P) is performed on one surface of the stretched microporous resin film base layer (I).   The cover material according to claim 3, wherein the surface on which the printing (P) is performed is a surface opposite to the surface on which the polyethylene terephthalate resin film layer (II) is formed.   The cover material according to claim 1 or 2, wherein printing (P) is performed on one surface of the polyethylene terephthalate resin film layer (II).   The cover material according to claim 1 or 2, wherein printing (P) is performed on one surface of the inorganic oxide thin film layer (III).   The total light transmittance (JIS K-7105) of a cover material is 5% or less, The cover material as described in any one of Claims 1-6.   The microporous resin stretched film base layer (I) comprises a uniaxially stretched film or a biaxially stretched film of a thermoplastic resin film containing 0 to 40% by weight of white inorganic fine powder and / or organic filler as a core layer (A And uniaxially stretched thermoplastic resin film containing 0 to 65% by weight of white inorganic fine powder and / or organic filler on both sides of the core layer as front and back layers (B, B ′). It is a film, The lid | cover material as described in any one of Claims 1-7 characterized by the above-mentioned. The lid material according to claim 8, wherein the porosity of the stretched microporous resin film base layer (I) represented by the following formula (1) is 10 to 60%.
[Formula 1]