JP4483448B2 - Lid material - Google Patents

Description

  The present invention relates to a lid for a container that is required to have gas barrier properties in the fields of food, medical / pharmaceutical products, electronic parts, and the like, and more specifically, has a high gas barrier property and high transparency. The present invention relates to a lid for a container for storing contents that need to be subjected to pressure and heat sterilization.

  In recent years, containers and lids used for packaging foods, medical / pharmaceuticals, electronic parts, etc., especially those that need to be sterilized by boiling or pressurized / heat sterilized, are altered in content, especially in foods, To suppress the oxidation and alteration of oils and fats, and to maintain the taste and freshness, and to suppress the alteration of active ingredients and maintain their efficacy in pharmaceutical products that require handling under aseptic conditions It is necessary to prevent the effects of oxygen, water vapor, and other gases that alter the contents of the container, gas barrier properties that block these gases, and resistance to boiling sterilization and pressure / heat sterilization treatment. Is required.

  Conventionally, containers for containers in the fields of food, pharmaceuticals, electronic parts, etc. have low gas permeability such as water vapor and oxygen because they have gas barrier properties and processing resistance such as boiling sterilization and pressure / heat sterilization. A material having a laminated structure consisting of For example, a transparent plastic film made of a material having a low gas permeability such as water vapor or oxygen and an aluminum foil bonded thereto, or a film obtained by depositing aluminum on the surface of the film has been used. However, lids using such metal foils are not affected by temperature and humidity and have excellent gas barrier properties against water vapor, oxygen, etc., but they are opaque, so the contents can be checked through the lid. Problems such as being unable to use a metal detector during inspection, and disposal after use must be treated as non-combustible material, and the aluminum foil remains as a lump in the incinerator during incineration. There was a harmful effect of hurting.

  On the other hand, as an alternative to aluminum foil, a coextruded multilayer film using a polyvinylidene chloride film, a polyvinyl alcohol film, an ethylene-vinyl alcohol copolymer film, and a metaxylylene adipamide resin as an intermediate layer is used.

  The above-mentioned polyvinylidene chloride film has poor heat resistance, and has a drawback that the gas barrier property after performing boiling sterilization or pressure / heat sterilization treatment is greatly reduced. Further, since it contains a large amount of chlorine, In addition, there are problems in waste disposal such as dioxin generation and recycling.

  In addition, since the polyvinyl alcohol film and the ethylene-vinyl alcohol copolymer film have large temperature dependency and humidity dependency, the gas barrier property is lowered at high temperature or high humidity, and particularly, the water vapor barrier property is low. There is a problem that the gas barrier property after performing boiling sterilization treatment or pressurization / heat sterilization treatment is remarkably lowered.

Below, patent documents are described.
U.S. Pat. No. 3,442,686 In recent years, as a packaging material that has overcome these drawbacks, for example, inorganic oxides such as silicon oxide, aluminum oxide, and tin oxide described in Patent Documents 1 and 2 are polymers. A film in which a deposited film is formed on a film by a forming means such as a vacuum deposition method or a sputtering method has been developed. These films are known to have transparency and gas barrier properties such as oxygen and water vapor, and are suitable as packaging materials having both transparency and gas barrier properties that cannot be obtained with metal foil or the like. .

  However, even if the packaging material described above is a film suitable for a lid material or the like, it is rarely used as a vapor-deposited film alone. Various post-processing such as bonding and shape processing. In particular, packaging materials that need to be subjected to boiling sterilization treatment or pressurization / heat sterilization treatment are sterilized through various processes, and thus the packaging materials must be carefully designed.

  Therefore, when the above-described vapor deposition film is used as a cover material, when boiling sterilization treatment or pressure / heat sterilization treatment is performed, there is a problem that delamination occurs in the sealed portion after sterilization or gas barrier properties are reduced. It was.

Patent documents are shown below.
Japanese Patent Publication No.53-12953, JP, 60-27532, A In addition, an inorganic oxide vapor deposition film in which silicon oxide or magnesium oxide is vapor-deposited on a polyethylene terephthalate film (polyester film), a polypropylene film, a polyamide film substrate or the like has been proposed (patent). References 3 and 4).

  Inorganic oxide vapor-deposited films are widely used as packaging materials because they are less dependent on the environment such as temperature and humidity for gas barrier performance than other gas barrier films, and have no problems such as toxicity at the time of disposal after use. It has come to be. And as a typical base material of the inorganic oxide vapor deposition film, since it is excellent in terms of mechanical strength, thermal characteristics, humidity characteristics, etc., a biaxially stretched polyester film is used, and it is also used as a lid material. ing.

  However, the cover material using a biaxially stretched polyester film has a small reduction in gas barrier properties after boiling sterilization or pressure / heat sterilization treatment, but the thermal shrinkage rate is small compared to other gas barrier films. The lid material after the boiling sterilization treatment and the like is in a “rippling” state, and there is a problem that the appearance is remarkably impaired and the commercial value is remarkably lowered.

  Moreover, although the inorganic oxide vapor deposition film using polyamide-type film base materials, such as a biaxially stretched nylon film, is also used for the lid | cover material, since a heat shrinkage rate is large, said biaxially stretched polyester film base material is used. There is no problem that the appearance of the lid material after being subjected to boiling sterilization treatment, such as when used, is in a “ripple” state, but compared to the case where a biaxially stretched polyester film substrate is used. The gas barrier properties are inferior and the cost is high. In addition, due to the essential properties of nylon films, which have a high moisture absorption coefficient and humidity expansion coefficient, flatness deteriorates when the film is stored in roll form, causing problems in handling during vapor deposition, printing, and laminating.

  The present invention has been made in order to solve the above-described problems, and has high gas barrier properties, high transparency, and high adhesion, and contents that need to be subjected to boiling sterilization or pressure / heat sterilization treatment. The object is to provide a lid for containers in the fields of food, medicine / medicine, electronic parts and the like to be stored.

In order to achieve the above purpose, that is,
The invention according to claim 1
In the lid that seals the opening of the container,
A cover material comprising a transparent gas barrier laminate in which at least an anchor coat layer, a transparent gas barrier vapor deposition layer made of an inorganic oxide, a gas barrier coating layer, and a heat-sealable resin film are sequentially laminated on a specific polyester film substrate. Because
The specific polyester film has an elastic modulus of 0.5 to 5.0 GPa, a puncture strength of 195 N / mm or more, and a hot-water heat shrinkage rate at 120 ° C. for 30 minutes in the film longitudinal direction and the transverse direction. A lid material characterized by being a biaxially stretched polyester film having a direction of more than 2% and 4% or less.

The invention according to claim 2
2. The lid according to claim 1, wherein the inorganic oxide is aluminum oxide, silicon oxide, magnesium oxide or a mixture thereof.

The invention according to claim 3
The gas barrier coating layer is mainly composed of an aqueous solution or water / alcohol mixed solution containing at least one of a water-soluble polymer and (a) one or more metal alkoxides and hydrolysates thereof, or (b) tin chloride. The lid material according to claim 1 or 2, wherein a coating agent is applied and dried by heating.

The invention according to claim 4
The said anchor coat layer consists of a composite of an acrylic polyol, an isocyanate compound, and a silane coupling agent, The lid | cover material of any one of Claims 1-3 characterized by the above-mentioned.

  An object of the lid material of the present invention is to provide a lid material having high gas barrier properties, high transparency, and high adhesiveness, and excellent in processing resistance such as boiling sterilization and pressure / heat sterilization treatment.

  That is, the lid material of the present invention can be held without damaging the gas barrier properties even when used for a long time under high humidity conditions.

  The lid material of the present invention has excellent processing resistance such as boiling sterilization and pressure / heat sterilization treatment, no deterioration of gas barrier properties after processing, occurrence of delamination, occurrence of poor appearance, boiling sterilization and pressure / It can be suitably used as a lid for containers in the fields of food, medical / pharmaceuticals, electronic parts and the like that contain contents that need to be heat sterilized.

  Moreover, it is excellent in post-processing aptitude, such as vapor deposition, printing, laminating in the inorganic oxide vapor-deposited film constituting the lid material of the present invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the configuration of the lid of the present invention.

  As shown in FIG. 1, a lid 10 as an embodiment of the present invention includes at least an anchor coat layer 2, a transparent gas barrier vapor deposition layer 3 made of an inorganic oxide, and a gas barrier on a specific polyester film substrate 1. A lid for sealing an opening of a container, in which a heat-sealable resin film 7 is laminated on a gas barrier coating layer 4 of a transparent gas barrier laminate 5 formed by laminating a conductive coating layer 4 in this order via an adhesive layer 6 It is a material.

  The specific polyester film has an elastic modulus of 0.5 to 5.0 GPa, a puncture strength of 195 N / mm or more, and a hot water heating shrinkage rate at 120 ° C. for 30 minutes in the longitudinal direction and It is a biaxially stretched polyester film that is larger than 2% and not larger than 4% in the transverse direction.

The polyester film used in the present invention is not particularly limited as long as the elastic modulus, puncture strength, and hot water heat shrinkage rate of the film satisfy the above-mentioned characteristics. For example, as a dicarboxylic acid component constituting the polyester, Aromatic dicarboxylic acids, alicyclic dicarboxylic acids, aliphatic dicarboxylic acids, polyfunctional acids and the like can be mentioned. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, diphenic acid, and derivatives thereof. Examples of alicyclic dicarboxylic acids include 1,4-cyclohexanedicarboxylic acid and derivatives thereof. Aliphatic dicarboxylic acids include adipic acid, sebacic acid, dodecanedioic acid, eicoic acid, dimer acid and derivatives thereof, and polyfunctional acids include trimellitic acid, pyromellitic acid and derivatives thereof, etc. It is representative. Representative examples of the alcohol component include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, bisphenol, and derivatives thereof. It is a thing. Further, it includes a polyester ether copolymerized with a polyether such as polyethylene glycol and polytetramethylene glycol, a polyester amide copolymerized with a polyamide, and a block copolymer with an aliphatic polyester such as polycaprolactone.

  Among these polyesters, from the viewpoints of film forming properties such as biaxial stretching properties, humidity properties, heat resistance, chemical resistance, low cost, and other viewpoints, polyethylene terephthalate (PET) is the main component, preferably polyester. Polyesters in which 50 mol% or more of each of the acid component and the alcohol component are terephthalic acid, ethylene glycol and derivatives thereof are preferably used in the polyester film of the present invention.

  Furthermore, for the polyester film of the present invention, for example, it is effective to copolymerize an aliphatic dicarboxylic acid, a polyether, an aliphatic polyester, etc. with a polyester mainly composed of PET. Copolymerization of a long-chain aliphatic dicarboxylic acid having 20 or more alkylene groups is preferred in terms of weather resistance and quality stability. Examples of the long-chain aliphatic dicarboxylic acid include dodecanedioic acid, eicoic acid, dimer acid, and derivatives thereof. In particular, in the present invention, a branched aliphatic dicarboxylic acid having a branched structure may be used. From the viewpoint of improving impact resistance, it is preferable to use dimer acid among them for improving heat resistance and transparency.

  Here, dimer acid is a general term for a mixture of a chain-branched structure and a cyclic-branched structure obtained by dimerization / hydrogenation reaction of unsaturated aliphatic dicarboxylic acid such as methyl oleate, and methylene chain carbon. The number is 20 to 80, preferably 30 to 60. Moreover, although an unsaturated bond remains normally, what set the bromine number measured by ASTM-D-1159 to 0.1-10 (g / 100g) is preferable since it is excellent in heat resistance and a softness | flexibility. The copolymerization amount of the dimer acid is preferably 5 to 30 mol% with respect to the acid component.

  Next, although the manufacturing method of the polyester film in this invention is described, it is not limited to this. The polyester is melt-extruded by an extruder, and the resulting film is produced by a normal sequential biaxial stretching film forming process in which longitudinal stretching, lateral stretching, and heat treatment are further performed. In addition, a simultaneous biaxial stretching process or the like can also be employed.

  In the above-described sequential biaxial stretching process, simultaneous biaxial stretching process, and the like, the stretching ratio and the heat treatment temperature are important for achieving the physical property values of the polyester film in the present invention. In particular, the puncture strength is affected by the draw ratio and the heat treatment temperature, the draw ratio (longitudinal draw ratio × lateral draw ratio) is preferably 5 to 20 times, and the heat treatment temperature is preferably 150 to 240 ° C. When the draw ratio is low or high, the puncture strength is drastically decreased. When the heat treatment temperature is low, the puncture strength is low. When the heat treatment temperature is high, the elastic modulus and the like are decreased and the film is broken. Moreover, when the pin puncture strength based on the food hygiene law, the standard standard of an instrument, and a container packaging is as low as less than 195 N / mm, it is not preferable because a pinhole is easily generated in the film when used as a lid. The hot water heat shrinkage rate under the conditions of 120 ° C. for 30 minutes when the film is formed under the above conditions is greater than 2% and 4% or less in both the film longitudinal direction and the film transverse direction. When the hot water heat shrinkage is 2% or less, the cover material after the boiling sterilization or the heating / pressure sterilization treatment has a small shrinkage, so that undulation occurs and the appearance is impaired. Moreover, since shrinkage | contraction is large when a hot-water heating shrinkage rate exceeds 4%, the fall of the gas barrier property after a sterilization process will become large. Further, the elastic modulus is preferably in the range of 0.5 to 5.0 GPa, and when the elastic modulus is too low, the film does not have “stiffness”. Moreover, since the elasticity modulus falls when the heat processing temperature is high, it is unpreferable.

  If necessary, the polyester film substrate 1 may be treated with, for example, corona discharge treatment, ozone treatment, oxygen gas or nitrogen gas, low temperature plasma treatment, glow discharge treatment, chemicals, etc. Preprocessing such as processing and others can be arbitrarily performed.

  The cover material in the present invention may be provided with a printing layer. The printed layer is laminated on the surface of the gas barrier coating layer 4 of the transparent gas barrier laminate 5. This printed layer is formed for practical use as a packaging material, a packaging bag, or the like. As the printing layer, for example, an ordinary gravure ink composition, an offset ink composition, a relief printing ink composition, a screen ink composition, and other ink compositions are used on the first substrate. For example, using a gravure printing method, offset printing method, letterpress printing method, silk screen printing method, or other printing method, for example, forming a desired printed pattern made up of characters, figures, patterns, symbols, etc. This can be configured. In the above, various ink compositions include, for example, as a vehicle constituting the ink composition, for example, polyolefin resins such as polyethylene resins and chlorinated polypropylene resins, poly (meth) acrylic resins, polyvinyl chloride Resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate copolymer, polystyrene resin, styrene-butadiene copolymer, vinylidene fluoride resin, polyvinyl alcohol resin, polyvinyl acetal resin, Polyvinyl butyral resin, polybutadiene resin, polyester resin, polyamide resin, alkyd resin, epoxy resin, unsaturated polyester resin, thermosetting poly (meth) acrylic resin, melamine resin, urea Resin, polyurethane resin, phenol resin, xylene resin, Inic acid resin, nitrocellulose, ethyl cellulose, acetylbutyl cellulose, cellulose resin such as ethyloxyethyl cellulose, rubber resin such as chlorinated rubber and cyclized rubber, petroleum resin, rosin, casein A natural resin such as linseed oil, fats and oils such as linseed oil and soybean oil, and a mixture of one or more resins such as others can be used. Then, one or two or more of the above-mentioned vehicles are used as a main component, and one or more of coloring agents such as dyes and pigments are added to this, and if necessary, for example, a filler, Add stabilizers, plasticizers, antioxidants, UV stabilizers and other light stabilizers, dispersants, thickeners, desiccants, lubricants, antistatic agents, crosslinking agents, etc. Ink compositions having various forms obtained by sufficiently kneading with a diluent or the like can be used.

  The anchor coat layer 2 in the present invention is an anchor coat layer made of a composite of an acrylic polyol, an isocyanate compound and a silane coupling agent.

  The composition constituting the anchor coat layer 2 will be described in more detail. The acrylic polyol as the composition constituting the anchor coat layer 2 used in the present invention is obtained by polymerizing an acrylic acid derivative monomer. Among molecular compounds or polymer compounds obtained by copolymerizing acrylic acid derivative monomers and other monomers, those having a hydroxyl group at the terminal and reacted with the isocyanate group of the isocyanate compound added later . Among these, those obtained by polymerizing acrylic acid derivative monomers such as ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate alone, and acrylic polyols obtained by copolymerizing with other monomers such as styrene are preferably used. In consideration of the reactivity with the isocyanate compound, the hydroxyl value is preferably between 5 and 200 (KOHmg / g).

  The isocyanate compound as a composition constituting the anchor coat layer 2 used in the present invention is formed of the base (1) and the transparent gas barrier vapor deposition layer 3 made of an inorganic oxide by a urethane bond formed by reaction with an acrylic polyol. It is added to improve the adhesion, and mainly acts as a crosslinking agent or a curing agent. To achieve this, the isocyanate compounds include aromatic tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), aliphatic xylene diisocyanate (XDI), hexadiene isocyanate (HMDI), and isophorone diisocyanate (IPDI). Monomers such as these and their polymers and derivatives are used. These are used alone or as a mixture.

  The blending ratio of the acrylic polyol and the isocyanate compound is not particularly limited. However, if the isocyanate compound is too small, curing may be poor, and if it is too much, blocking or the like occurs, which causes a processing problem. There is. Therefore, the mixing ratio of the acrylic polyol and the insocyanate compound is preferably 50 times or less of the isocyanate group derived from the isocyanate compound than the hydroxyl group derived from the acrylic polyol. Particularly preferred is a case where an isocyanate group and a hydroxyl group are blended in equal amounts. As a mixing method, a known method can be used and is not particularly limited.

  Moreover, the silane coupling agent as a composition which comprises the anchor coat layer 2 used by this invention can use the silane coupling agent containing arbitrary organic functional groups, for example, ethyl trimethoxysilane, vinyl Silane coupling such as trimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane One type or two or more types of agents or hydrolysates thereof can be used.

Further, among these silane coupling agents, those having a functional group that reacts with a hydroxyl group of an acrylic polyol or an isocyanate group of an isocyanate compound are particularly preferable. For example, those containing an isocyanate group such as γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β- (aminoethyl)- Those containing amino groups such as γ-aminopropyltriethoxysilane, γ-phenylaminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane Such as those containing an epoxy group, etc., and these can be used alone or in a mixture of two or more. These silane coupling agents contain a functional group in which an organic functional group present at one end exhibits an interaction in a composite composed of an acrylic polyol and an isocyanate compound, or reacts with a hydroxyl group of an acrylic polyol or an isocyanate group of an isocyanate compound. By providing a covalent bond by using a silane coupling agent, a stronger primer layer is formed, and the silanol group generated by hydrolysis of the alkoxy group at the other end is a metal in the inorganic oxide or an inorganic oxide. It exhibits high adhesion with inorganic oxides by strong interaction with a highly active hydroxyl group or the like on the surface, and the desired physical properties can be obtained. Therefore, you may use what hydrolyzed the said silane coupling agent with the metal alkoxide. Further, even if the alkoxy group of the silane coupling agent is a chloro group, an acetoxy group, etc., there is no problem, and these alkoxy groups, chloro groups, acetoxy groups, etc. are hydrolyzed to form silanol groups. If present, it can be used in this composite.

  The mixing ratio of the acrylic polyol and the silane coupling agent is preferably in the range of 1/1 to 100/1 by weight, more preferably in the range of 2/1 to 50/1.

  The dissolving and diluting solvent is not particularly limited as long as it can be dissolved and diluted. For example, esters such as ethyl acetate and butyl acetate, alcohols such as methanol, ethanol and isopropyl alcohol, ketones such as methyl ethyl ketone, A mixture of aromatic hydrocarbons such as toluene and xylene alone and arbitrarily can be used. However, since an aqueous solution such as hydrochloric acid or acetic acid may be used to hydrolyze the silane coupling agent, it is necessary to use a solvent in which isopropyl alcohol or the like and ethyl acetate that is a polar solvent are arbitrarily mixed as a co-solvent. More preferred.

In addition, it is possible to add a reaction catalyst to promote the reaction when the silane coupling agent is blended. Examples of the catalyst to be added include tin compounds such as tin chloride (SnCl ₂ , SnCl ₄ ), tin oxychloride (SnOHCl, Sn (OH) ₂ Cl ₂ ), and tin alkoxide from the viewpoint of reactivity and polymerization stability. It is possible to use. These catalysts may be added directly at the time of blending, or may be added after being dissolved in a solvent such as methanol.

  As a method for preparing a primer solution for forming a coating film of the composition in the present invention, a composite solution in which an acrylic polyol, an isocyanate compound, and a silane coupling agent are mixed in an arbitrary mixing ratio is manufactured, and the substrate ( It is formed by coating 1). As a method for producing the composition solution, a silane coupling agent and an acrylic polyol are mixed, a solvent and a diluent are added, diluted to an arbitrary concentration, and then mixed with an isocyanate compound, or a composite solution is prepared in advance. A method in which a silane coupling agent is mixed in a solvent and then mixed with an acrylic polyol is added to a solvent and a diluent, diluted to an arbitrary concentration, and then an isocyanate compound is added to prepare a composite solution. is there.

  Various additives such as tertiary amines, imidazole derivatives, carboxylic acid metal salt compounds, quaternary ammonium salts, quaternary phosphonium salts and other curing accelerators, phenolic, sulfur-based, phosphite-based, etc. These antioxidants, leveling agents, flow regulators, catalysts, crosslinking reaction accelerators, fillers, and the like can be added as necessary.

  The thickness of the anchor coat layer 2 is not particularly limited as long as a uniform coating film can be formed. However, the dry film thickness is generally preferably in the range of 0.01 to 2 μm. When the thickness is less than 0.01 μm, it is difficult to obtain a uniform coating film, and the adhesion may be lowered. On the other hand, if the thickness exceeds 2 μm, the coating film cannot be kept flexible because it is thick, and the coating film may be cracked due to external factors. The thickness of the anchor coat layer 2 is particularly preferably in the range of 0.05 to 0.5 μm.

As a method for forming the anchor coat layer 2, for example, a known printing method such as an offset printing method, a gravure printing method, or a silk screen printing method, or a known coating method such as a roll coating, a knife edge coating, or a gravure coating may be used. it can. As drying conditions, generally used conditions are employed.

  The transparent gas barrier vapor-deposited layer 3 made of an inorganic oxide forming the gas barrier layer in the present invention is made of a vapor-deposited film of an inorganic oxide such as aluminum oxide, silicon oxide, tin oxide, magnesium oxide, or a mixture thereof, and is transparent. And a layer having gas barrier properties such as oxygen and water vapor. Considering various sterilization resistances, it is more preferable to use aluminum oxide and silicon oxide among these. However, the transparent gas barrier vapor deposition layer 3 of the present invention is not limited to the above-described inorganic oxide, and any material that meets the above conditions can be used.

  The optimum thickness of the transparent gas barrier vapor-deposited layer 3 varies depending on the type and configuration of the inorganic oxide used, but is generally in the range of 5 to 300 nm, and the value is appropriately selected. However, if the film thickness is less than 5 nm, a uniform film may not be obtained or the film thickness may not be sufficient, and the function as a gas barrier material may not be sufficiently achieved. Further, when the film thickness exceeds 300 nm, the thin film cannot be kept flexible, and there is a problem because the thin film may be cracked due to external factors such as bending and pulling after the film formation. More preferably, it exists in the range of 10-150 nm.

  There are various methods for forming the transparent gas barrier vapor-deposited layer 3 made of an inorganic oxide on a plastic substrate, and it can be formed by a normal vacuum vapor deposition method. In addition, other thin film forming methods such as sputtering, ion plating, and plasma vapor deposition (CVD) can also be used. However, considering productivity, the vacuum deposition method is the best at present. As a heating means of the vacuum evaporation method, it is preferable to use any one of an electron beam heating method, a resistance heating method, and an induction heating method, but the electron beam heating method should be used in consideration of the wide selection of evaporation materials. Is more preferable. In order to improve the adhesion between the transparent gas barrier vapor-deposited layer 3 and the base material (1) and the denseness of the transparent gas barrier vapor-deposited layer 3, it is also possible to perform vapor deposition using a plasma assist method or an ion beam assist method. It is. In order to increase the transparency of the deposited film, it is possible to use reactive deposition in which various gases such as oxygen are blown during the deposition.

  Next, the gas barrier coating layer 4 that forms the gas barrier layer in the present invention will be described. The gas barrier coating layer 4 is formed using a coating agent mainly composed of an aqueous solution or water / alcohol mixed solution containing a water-soluble polymer and one or more metal alkoxides or hydrolysates thereof. For example, a solution obtained by mixing a water-soluble polymer dissolved in an aqueous (water or water / alcohol mixed) solvent with a metal alkoxide directly or previously hydrolyzed is used as a solution. This solution is formed by coating the transparent gas barrier vapor deposition layer 3 made of an inorganic oxide, which is a gas barrier layer, and then drying by heating. Each component contained in the coating agent will be described in more detail.

  Examples of the water-soluble polymer used as a coating agent for forming the gas barrier coating layer 4 in the present invention include polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, and sodium alginate. In particular, when polyvinyl alcohol (hereinafter abbreviated as PVA) is used for the coating agent of the present invention, the gas barrier property is most excellent, which is preferable. PVA here is generally obtained by saponifying polyvinyl acetate. As PVA, for example, complete PVA in which only a few percent of acetic acid groups remain can be used from so-called partially saponified PVA in which several tens percent of acetic acid groups remain, and other types may be used. .

The metal alkoxide is a compound represented by a general formula, M (OR) _n (M: metal such as Si, Ti, Al, Zr, or alkyl group such as R: CH ₃ , C ₂ H ₅ ). Specific examples include tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ] and triisopropoxyaluminum [Al (O-2′-C ₃ H ₇ ) ₃ ], among which tetraethoxysilane and triisopropoxy. Aluminum is preferable because it is relatively stable in an aqueous solvent after hydrolysis.

  It is also possible to add known additives such as isocyanate compounds, silane coupling agents, or dispersants, stabilizers, viscosity modifiers, and colorants to the solution as long as the gas barrier properties are not impaired. is there.

  As a method for applying the coating agent for forming the gas barrier coating layer 4, a conventionally known method such as a dipping method, a roll coating method, a screen printing method, a spray method, or a gravure coating method which are usually used can be used.

  The optimum thickness of the gas barrier coating layer 4 varies depending on the type of coating agent, the processing machine and processing conditions, and is not particularly limited. However, when the thickness after drying is 0.01 μm or less, a uniform coating film cannot be obtained, and sufficient gas barrier properties may not be obtained. On the other hand, when the thickness exceeds 50 μm, cracks are likely to occur in the film, which may be a problem. It is preferably in the range of 0.01 to 50 μm, more preferably in the range of 0.1 to 10 μm.

  The heat-sealable resin film 7 in the present invention is an adhesive thermoplastic resin that can be heat-sealable, can be extruded, and can be melted by heat and fused to each other. , Low density polyethylene, medium density polyethylene, high density polyethylene, linear (linear) low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate copolymer, ethylene-acrylic Polyolefin resin such as acid copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, polyethylene or polypropylene is used for acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumar Acid-modified polymers modified with unsaturated carboxylic acids such as acid, itaconic acid, etc. Olefin resins, polyvinyl acetate resins, polyester resins other such resins can be used.

  A transparent gas barrier polyester film 5 constituted by sequentially laminating an anchor coat layer 2, a transparent gas barrier vapor deposition layer 3 made of an inorganic oxide, and a gas barrier coating layer 4 on a specific polyester film substrate 1 in the present invention. The method of laminating the heat-sealable resin film layer 7 on the gas barrier coating layer 4 is not particularly limited, but the laminating method is preferable via the adhesive layer 6 by a dry lamination method.

Examples of the dry lamination adhesive that constitutes the adhesive layer 6 include a two-component curing type vinyl type, (meth) acrylic type, polyamide type, polyester type, polyether type, polyurethane type, and epoxy type. The two-component curable urethane-based adhesive is preferably used. Examples of the adhesive coating method include direct gravure roll coating method, gravure roll coating method, kiss coating method, reverse roll coating method, Fonten method, and transfer roller. -The coating method can be applied by a method such as a coat method, etc. The coating amount is 0.1 to 10 g / m ² (dry state), more preferably 1 to 5 g / m ² ( The dry state is desirable.

  Examples of the present invention will be specifically described below.

As a biaxially stretched polyester film, a film having a thickness of 12 μm was prepared at a longitudinal stretching ratio of 3.5 times, a transverse stretching ratio of 3.6 times, and a heat treatment temperature of 220 ° C. The elastic modulus of this biaxially stretched polyester film is 3.9 GPa in the longitudinal direction of the film, 4.0 GPa in the transverse direction of the film, 392 N / mm of puncture strength, and the hot water heating shrinkage rate at 120 ° C. for 30 minutes is The film longitudinal direction was 3.2%, and the film transverse direction was 2.5%. One side of this 12 μm thick biaxially stretched polyester film is subjected to corona treatment, and the anchor coat liquid shown below is applied to the corona-treated surface by a gravure coating method and dried, and the thickness after drying is 0.1 μm. The anchor coat layer was laminated. Thereafter, curing was performed at 50 ° C. for 2 days to promote adhesion of the anchor coat layer.

  Then, the transparent gas barrier vapor deposition layer which consists of aluminum oxide with a thickness of 20 nm was laminated | stacked on the surface of the anchor coat layer of the biaxially stretched polyester film which laminated | stacked the said anchor coat layer by the vacuum vapor deposition apparatus by an electron beam heating system.

  Further, on the transparent gas barrier vapor-deposited layer, a gas barrier coating liquid having the composition shown below was applied by a gravure coating method and dried to obtain a transparent gas barrier laminate in which the gas barrier coating layer was laminated.

Subsequently, a polyurethane adhesive (“A525 / A52” manufactured by Mitsui Takeda Chemical Co., Ltd.) was applied on the gas barrier coating layer surface of the transparent gas barrier polyester film by a dry lamination method to a coating amount of 3.5 g / m ² . An adhesive layer is formed, and a heat-sealable resin film made of a linear low-density polyethylene film (“TUX-FCD” manufactured by Tosero Co., Ltd.) having a thickness of 50 μm is laminated thereon and cured at 40 ° C. for 4 days. The lid material of the present invention was made.

<Adjustment of anchor coating solution>
Isocyanate resin (solid content 50% by weight) with respect to 7g of solution (solid content 20% by weight) prepared by diluting solvent by mixing and stirring 0.6g of isocyanate propyltrimethylsilane with acrylic polyol 6g (solid content 50% by weight) 1.5 g and a diluting solvent were added and stirred for 30 minutes to adjust the solid content to 2% by weight to prepare an anchor coat solution.

<Adjustment of gas barrier coating liquid>
Add 89.6 g of hydrochloric acid (0.1N) to 10.4 g of tetraethoxysilane, and mix the hydrolyzed solution with a solid content of 3% by weight (SiO ₂ equivalent) and 30% by weight of polyvinyl alcohol and 3 wt% of polyvinyl alcohol. Thus, a gas barrier coating solution was prepared.

  In Example 1, a lid material of the present invention was prepared in the same manner as in Example 1 except that aluminum oxide having a thickness of 20 nm as a transparent gas barrier vapor deposition layer made of an inorganic oxide was changed to silicon oxide having a thickness of 40 nm. .

  In order to compare the performance with the lid material of the present invention, in Example 1, as a biaxially stretched polyester film, the elastic modulus is 4.4 GPa in the film longitudinal direction, 4.5 GPa in the film lateral direction, and the puncture strength is 343 N / Mm and 120 ° C. for 30 minutes under conditions of hot water heating, except that a biaxially stretched polyester film having physical properties of 1.5% in the film longitudinal direction and 0.5% in the film transverse direction is used. Produced a lid as a comparative example in the same manner as in Example 1.

In order to compare the performance with the lid material of the present invention, in Example 1, instead of the biaxially stretched polyester film, the elastic modulus is 1.5 GPa in the film longitudinal direction, 0.9 GPa in the film transverse direction, and the puncture strength Biaxial stretching with a thickness of 15 μm having a physical property of 5.5% in the longitudinal direction of the film and 3.2% in the transverse direction of the film under a condition of 637 N / mm and 120 ° C. for 30 minutes. A cover material as a comparative example was prepared in the same manner as in Example 1 except that a nylon film was used.

  The lid materials obtained in Examples 1 to 4 were evaluated for gas barrier properties and the appearance of the lid material based on the evaluation methods described below. The evaluation results are shown in Table 1. Table 1 also shows the comprehensive evaluation.

<Creation of evaluation sample>
The lids obtained in Examples 1 to 4 were cut into a circular shape, and sealed in the opening of a 90-ml barrier cup-shaped container filled with a gel prepared based on the gel adjustment method shown below. Sealed. Using a transparent gas barrier laminate, a 100 mm × 150 mm four-way seal pouch was prepared, and after filling with 150 g of distilled water as a content, sterilization treatment was performed at 95 ° C. for 60 minutes in a boil tank.

<Gel preparation method>
Dissolve 1.5 g of sucrose fatty acid ester in 1500 ml of heated water, add 22.5 g of agar powder, 0.72 g of sodium hydroxide, 90 g of D-glucose and 0.225 g of methylene blue, and then remove oxygen. To boil for 10 minutes.

<Evaluation method>
The gas barrier property was evaluated by observing the color change of the gel of the contents immediately after sterilization by boiling at 95 ° C. for 60 minutes and after storage for 1 month at room temperature. This gel reacts with oxygen and changes color from yellow to blue. That is, if oxygen does not permeate the container, it retains yellow color, while if the oxygen permeation is large, the gel gradually turns blue. If the gel color is yellow, it indicates that the gas barrier property is maintained, and if the gel color is changed to blue, the gas barrier property is deteriorated.

  Moreover, the external appearance of the lid | cover material by the presence or absence of the "waving" state of the lid | cover material when boiled and sterilized at 95 degreeC for 60 minutes was evaluated. The evaluation was performed in three stages: ○ (excellent), Δ (inferior), and x (extremely inferior, not practical).

表１には、総合評価についても記してある。

Table 1 also describes the overall evaluation.

  From Table 1, the lid material of the present invention obtained in Examples 1 and 2, the gel of the content immediately after boiling sterilization and after storage for 1 month at room temperature is yellow, there is no color change, gas barrier properties are maintained, It has excellent gas barrier properties. In addition, the “waving” state of the lid material after boiling sterilization was not observed and was highly practical.

  On the other hand, the lid material obtained in Example 3 as a comparative example for comparing the performance with the lid material of the present invention maintains the gas barrier properties immediately after boiling and sterilization and after storage at room temperature for 1 month. The “waving” state of the lid material after boiling sterilization was remarkable, the appearance was remarkably impaired, and there was a problem in practical use. In addition, as a comparative example for comparing the performance with the lid material of the present invention, the lid material obtained in Example 4 has a room temperature 1 after boiling sterilization, although the “waving” state of the lid material after boiling sterilization is not observed. The gel of the contents after storage for months showed a color change from yellow to slightly blue, and the gas barrier property after boiling sterilization deteriorated.

From a comprehensive evaluation, the lid material of the present invention is excellent in processing resistance such as boiling sterilization and pressure / heat sterilization treatment, there is no decrease in gas barrier properties and delamination after processing, boiling sterilization and pressure / It can be suitably used as a lid material for containers in the fields of food, medical / pharmaceuticals, electronic parts and the like that contain contents that need to be heat sterilized. Moreover, the lid | cover material of this invention has a high gas barrier property and high transparency.

It is sectional drawing which shows an example of a structure of the cover material of this invention.

Explanation of symbols

1 ... Base material (specific polyester film)
DESCRIPTION OF SYMBOLS 2 ... Anchor coat layer 3 ... Transparent gas barrier vapor deposition layer 4 which consists of inorganic oxides ... Gas barrier coating layer 5 ... Transparent gas barrier laminated body 6 ... Adhesive layer 7 ... Heat Sealing resin film 10 ... cover material

Claims (4)

A container comprising a transparent gas barrier laminate formed by sequentially laminating at least an anchor coat layer, a transparent gas barrier vapor deposition layer made of an inorganic oxide, a gas barrier coating layer, and a heat sealable resin film on a specific polyester film substrate. A lid that seals the opening,
The specific polyester film has an elastic modulus of 0.5 to 5.0 GPa, a puncture strength of 195 N / mm or more, and a hot water heating shrinkage rate at 120 ° C. for 30 minutes in both the vertical direction and the horizontal direction. A lid material which is a biaxially stretched polyester film which is larger than 2% and not larger than 4%.   The lid material according to claim 1, wherein the inorganic oxide is aluminum oxide, silicon oxide, magnesium oxide, or a mixture thereof.   The gas barrier coating layer is mainly composed of an aqueous solution or water / alcohol mixed solution containing at least one of a water-soluble polymer and (a) one or more metal alkoxides and hydrolysates thereof, or (b) tin chloride. The lid according to claim 1 or 2, wherein a coating agent is applied and dried by heating.   The said anchor coat layer consists of a composite of an acrylic polyol, an isocyanate compound, and a silane coupling agent, The lid | cover material of any one of Claims 1-3 characterized by the above-mentioned.

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