JP2006007566A - Transparent gas barrier laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent gas barrier laminate which has high gas barrier properties to oxygen, steam or the like as an important characteristic in a packaging film for food product, medical care, pharmaceuticals, electronic components or the like, and especially has improved high impact properties and pinhole resistance. <P>SOLUTION: This transparent gas barrier laminate has at least an anchor coat layer, a transparent gas barrier vapor deposition layer formed of an inorganic oxide, a gas barrier coated layer and a heat sealing resin film laminated in that order on a specific polyester film base. The specific polyester film has 9×10<SP>8</SP>to 1×10<SP>10</SP>Pa storage modulus (E') at -20 to +40°C and also, recognized dynamic viscoelasticity at not higher than +10°C β-transition tanδpeak temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transparent gas barrier laminate used as a packaging material in fields requiring gas barrier properties such as foods, medical / pharmaceuticals, and electronic parts, and more particularly, a specific polyester film is used as a base material. The present invention relates to a transparent gas barrier laminate having improved transparency and high gas barrier properties with improved impact resistance and pinhole resistance.

  In recent years, packaging materials used for packaging foods, medical / pharmaceuticals, electronic parts, etc. have been used to suppress the alteration of contents, especially the oxidation and alteration of proteins and oils and fats in food, and to maintain the taste and freshness. In addition, in pharmaceutical products that require handling under aseptic conditions, the effects of oxygen, water vapor, and other gases that alter the contents of the permeation of the packaging material in order to suppress the alteration of the active ingredient and maintain its efficacy. Therefore, it is required to have a gas barrier property to block these gases.

  Transparent plastic films used for packaging materials for foods, pharmaceuticals, electronic parts and the like are made of a material having a low gas permeability such as water vapor or oxygen in order to prevent deterioration of the packaged contents. In the case of packaging materials that require a higher degree of gas barrier properties, those in which an aluminum foil is bonded to a film or those in which aluminum is evaporated on the surface of the film have been used. However, packaging materials using such metal foils are excellent in gas barrier properties against water vapor, oxygen, etc., but are opaque and have the disadvantage that the contents cannot be seen from the outside. There was an unsuitable aspect.

  On the other hand, polyvinylidene chloride, a film made of vinylidene chloride as a main component, and other compounds copolymerizable with this, for example, vinylidene chloride resins such as vinyl chloride, methyl acrylate, methyl methacrylate, acrylonitrile copolymer, In addition, vinylidene chloride resin coated films obtained by coating these vinylidene chloride resins on a film made of polypropylene, polyester, polyamide or the like are also used as packaging materials having gas barrier properties. In these films, the film itself has a gas barrier property against water vapor, oxygen, and the like, and the humidity dependency is small, but there is a problem that it is difficult to realize an advanced gas barrier material (high gas barrier material). In addition, since the coating contains a large amount of chlorine, there is a problem in terms of waste treatment such as incineration and recycling.

Further, a packaging film generally used as a packaging material as a gas barrier laminate by laminating or coating a polymer resin composition generally said to have relatively high gas barrier properties such as polyvinyl alcohol and ethylene-vinyl alcohol copolymer is generally used. Have been used. In addition, a metal-deposited film obtained by depositing a metal such as Al or a metal compound on an appropriate polymer resin composition (even a resin that does not have high gas barrier properties alone), and recently, silicon monoxide ( A vapor-deposited film in which a silicon oxide (SiO _x ) thin film such as SiO) or a magnesium oxide (MgO) thin film is formed on a base material made of a polymer material having transparency has been developed. These have gas barrier properties superior to those of a gas barrier material made of a polymer resin composition, have little deterioration under high humidity, and packaging films used for packaging materials have begun to be generally used.

However, since the gas barrier laminate using the above-mentioned polymer resin composition of polyvinyl alcohol and ethylene-vinyl alcohol copolymer has a large temperature dependency and humidity dependency, the gas barrier property of the gas barrier property at high temperature or high humidity. Decrease is observed, especially there is no water vapor barrier property, and depending on the use of packaging, when performing boiling treatment or retort treatment, the gas barrier property may be remarkably lowered.

  Therefore, in order to provide such a laminated film with a high degree of gas barrier properties, the thickness of the laminated film must be increased. If the film thickness is increased, the transparency and flexibility of the laminated film are impaired. Therefore, there has been a disadvantage that properties preferable as a packaging material are lost.

Patent documents are shown below.
Japanese Patent Publication No.53-12953, JP, 60-27532, A Moreover, the film which vapor-deposited silicon oxide and magnesium oxide on a polyethylene terephthalate film, a polypropylene film, a polyamide system film, etc. is also proposed (refer to patent documents 1 and patent documents 2). These films are also insufficient for applications that require a high degree of gas barrier properties.

  In addition, a film in which silicon oxide or magnesium oxide is vapor-deposited on a polyamide film is inferior in gas barrier property to a film in which silicon oxide or magnesium oxide is vapor-deposited on polyethylene terephthalate film or polypropylene film, and a high gas barrier property is required. It was difficult to apply to the intended use.

  Furthermore, the above-mentioned metal vapor-deposited film vapor-deposited metal or metal compound, silicon oxide thin film such as silicon monoxide (SiO), vapor-deposited film vapor-deposited magnesium oxide (MgO) thin film is an inorganic compound thin film used for gas barrier layer Is inflexible, weak against bending and bending, and has poor adhesion to the base material, so it needs to be handled with care, especially during post-processing of packaging materials such as printing, laminating, bag making, etc. There is a problem that the gas barrier property is remarkably lowered due to the generation of cracks. In addition, since the formation method is performed using a vacuum process such as a vacuum deposition method, a sputtering method, a plasma chemical vapor deposition method, etc., the apparatus is expensive, and the substrate is locally heated in the formation process, causing damage to the substrate. May cause defects, pinholes, etc. in the inorganic thin film due to generation, decomposition of low molecular weight parts or additive parts such as plasticizers, degassing, etc., and high gas barrier properties cannot be achieved, cost It has a problem of becoming expensive.

  Furthermore, as a base material composed of a conventional polymer resin composition such as polyamide such as nylon, polyamide film such as nylon has a problem in characteristics, and particularly has an essential property that a moisture absorption coefficient and a humidity expansion coefficient are large. When the film is stored in a roll shape, the flatness is deteriorated, which causes a problem in handling in vapor deposition, printing and laminating. In contrast, the conventional polyester film has both a very low moisture absorption rate and humidity expansion coefficient, and has no problem with humidity characteristics, but has problems with puncture strength, impact resistance, and pinhole resistance. There is a problem as a packaging material in a field where properties are required.

  The present invention has been made to solve the above problems, and has a high gas barrier property against oxygen, water vapor and the like, which are important characteristics in packaging films for foods, medical / pharmaceuticals, electronic parts and the like, and An object of the present invention is to provide a transparent gas barrier laminate having improved impact resistance and pinhole resistance.

In order to achieve the above purpose, that is,
The invention according to claim 1
On a specific polyester film substrate, at least an anchor coat layer, a transparent gas barrier vapor deposition layer made of an inorganic oxide, a gas barrier coating layer, a transparent gas barrier laminate formed by sequentially laminating a heat sealable resin film,
The specific polyester film has a storage elastic modulus (E ′) at −20 to + 40 ° C. in the range of 9 × 10 ⁸ to 1 × 10 ¹⁰ Pa and a β transition tan δ peak temperature of + 10 ° C. or lower. It is a transparent gas barrier laminate characterized by having a dynamic viscoelasticity.

The invention according to claim 2
2. The transparent gas barrier laminate 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 transparent gas barrier laminate according to claim 1 or 2, wherein a coating agent is applied and dried by heating.

The invention according to claim 4
The transparent gas barrier laminate according to any one of claims 1 to 3, wherein the anchor coat layer is composed of a composite of an acrylic polyol, an isocyanate compound, and a silane coupling agent.

  Since the transparent gas barrier laminate of the present invention is configured as described above, it has a high gas barrier property against oxygen, water vapor, etc., and in particular, provides a transparent gas barrier laminate having excellent impact resistance and pinhole resistance. it can.

  In addition, the transparent gas barrier laminate of the present invention can retain gas barrier properties and laminate strength without being impaired even when used for a long time under high humidity conditions, and is excellent in boil and retort resistance.

  Therefore, the transparent gas barrier laminate of the present invention is suitably used as a packaging material in fields requiring gas barrier properties such as foods, medical / pharmaceuticals, and electronic parts.

  According to the present invention, from the essential properties of the hygroscopicity and humidity expansion coefficient of polyamide films such as nylon that have been conventionally used as a gas barrier substrate, the flatness deteriorates when the film is stored in a roll shape, The handling problems in vapor deposition, printing and laminating can be solved. Moreover, the problems regarding the puncture strength, impact resistance, and pinhole resistance of a polyester film that has been used as a gas barrier substrate, both of which are conventionally very low in moisture absorption rate and humidity expansion coefficient, can be solved. In particular, it can be used for packaging materials in a wide range of fields that require impact resistance and pinhole resistance, and its industrial utility value is great.

Hereinafter, an embodiment of a transparent gas barrier laminate as an example of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the configuration of the transparent gas barrier laminate of the present invention. As shown in FIG. 1, a transparent gas barrier laminate 10 according to an embodiment of the present invention includes a specific polyester film substrate 1, an anchor coat layer 2, a transparent gas barrier vapor deposition layer 3 made of an inorganic oxide, and a gas barrier. A heat-sealable resin film layer 7 is laminated with an adhesive layer 6 on the gas-barrier coating layer 4 of the transparent gas-barrier polyester film 5 configured by sequentially laminating the conductive coating layer 4.

The specific polyester film constituting the substrate 1 in the present invention has a storage elastic modulus (E ′) at a temperature of −20 to + 40 ° C. in a range of 9 × 10 ⁸ to 1 × 10 ¹⁰ Pa, and The polyester film is not particularly limited as long as it is a polyester film having dynamic viscoelasticity having a dynamic viscoelasticity observed at a β transition tan δ peak temperature of + 10 ° C. or lower. When the storage elastic modulus (E ′) is less than 9 × 10 ⁸ Pa, the flexibility of the polyester film is insufficient, and impact resistance and pinhole resistance equivalent to biaxially stretched nylon cannot be obtained. On the other hand, when the storage elastic modulus (E ′) exceeds 9 × 10 ⁸ Pa, flexibility is sufficient, but handling properties as a stretched film are inferior. Furthermore, when the peak temperature due to the β transition of the polyester film is not observed at + 10 ° C. or lower, the molecular chain cannot respond to an external load in the low temperature region, so deformation in the low temperature region is difficult, Insufficient bending pinhole resistance.

  As the polyester film, for example, the resin component (A) has a melting point of 240 to 265 ° C., and 90% by weight or more of a resin component composed of a polyester component composed of ethylene terephthalate and / or ethylene naphthalate 55 to 95% % And (B) a biaxially stretched polyester film having a melting point of 185 to 235 ° C. and a resin content of 5 to 45% by weight, wherein 70% by weight or more is a polyester component.

  Polyesters (A) and (B) that constitute a biaxially stretched polyester film are generic names for polymers that have ester bonds as the main bonds in the main chain, and usually a polycondensation of a dicarboxylic acid component and a glycol component. It can be obtained by reacting.

  Examples of the dicarboxylic acid component used here include terephthalic acid and naphthalenedicarboxylic acid, as well as aromatic substances such as isophthalic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sodiumsulfoisophthalic acid, and phthalic acid. Aliphatic dicarboxylic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, cyclohexyne dicarboxylic acid and other alicyclic dicarboxylic acids, p-oxybenzoic acid and the like An oxycarboxylic acid or the like can be used.

  In addition to ethylene glycol, the glycol component includes aliphatic glycols such as propanediol, butanediol, pentanediol, hexanediol and neopentylglycol, alicyclic glycols such as cyclohexanedimethanol, bisphenol A, bisphenol S and the like. Polyoxyalkylene glycols such as aromatic glycol, diethylene glycol, polyethylene glycol, and polypropylene glycol can be used.

  Two or more of these dicarboxylic acid components and glycol components may be used in combination.

  As long as the effect is not inhibited, polyfunctional compounds such as trimellitic acid, trimesic acid, and trimethylolpropane can be copolymerized.

Modified polybutylene terephthalate (PBT) can be obtained by melt-kneading polybutylene terephthalate and polyether obtained by the polycondensation reaction described above with an extruder, and in the polymerization step of polybutylene terephthalate. It can obtain by adding and polycondensing. The polyether here is a polyoxyalkylene glycol such as polyethylene glycol, polypropylene glycol or polytetramethylene glycol, and polyethylene terephthalate may be mixed with the polyether as long as the effects of the present invention are not impaired. . The proportion of block copolymerization of polyether with PBT is preferably 20 to 85% by weight, more preferably 30 to 75% by weight, and particularly preferably 40 to 65% by weight.

  A block copolymer (soft segment) having a small rotational hindrance is formed in the molecular chain by block copolymerization of the polyester with another polymer, particularly a linear polyether. Impacts from the outside, impacts caused by bending, etc. are absorbed by the soft segment in the molecular chain, resulting in excellent impact resistance and flexibility.

  If necessary, the polyester film substrate 1 is 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.

  It is also possible to laminate a printing layer on one surface of the polyester film substrate. The 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, and 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 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, the curing may be poor, and if it is too much, blocking or the like occurs, resulting in processing problems. There is. Therefore, as a blending ratio of the acrylic polyol and the insocyanate compound, it is preferable that the isocyanate group derived from the isocyanate compound is 50 times or less of 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.

  In the present invention, the transparent gas barrier vapor-deposited layer 3 made of an inorganic oxide that forms a gas barrier layer in the present invention is composed of an aluminum oxide, silicon oxide, tin oxide, magnesium oxide, or those transparent gas barrier vapor-deposited layers 3 made of an inorganic oxide. Any layer composed of a vapor-deposited film of an inorganic oxide such as a mixture and having transparency and a gas barrier property such as oxygen and water vapor may be used. 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-deposited layer 3 made of an inorganic oxide, which is the first 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 several 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 coating method of the coating agent for forming the gas barrier film layer 4, conventionally known methods such as a dipping method, a roll coating method, a screen printing method, a spray method, a gravure printing method and the like 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 the 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.

  As the heat-sealable resin film 7 in the present invention, the adhesive thermoplastic resin that can be heat-sealed may be any one that can be extruded and can be melted by heat and fused to each other. For example, 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 acid copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer, methyl pentene polymer, polyolefin resin such as polyethylene or polypropylene, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumar Acids modified with unsaturated carboxylic acids such as formic acid, itaconic acid, etc. Sex polyolefin 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 a laminating method by a dry lamination method is preferable.

Any of the two-component curable urethane adhesives can be used as the above-mentioned dry lamination adhesive. For example, one-component or two-component curable vinyl-based, (meth) acrylic, polyamide Adhesives such as polyesters, polyesters, polyethers, polyurethanes, and epoxies can be used. Examples of the coating method of the above-mentioned adhesive include, for example, a direct gravure roll coat method, a gravure roll coat method, a kiss coat method, a reverse roll coat method, a Fonten method, and a transfer method. The coating can be performed by a roll coating method or the like, and the coating amount is about 0.1 to 10 g / m ² (dry state), more preferably 1 to 5 g / m ^2. (Dry state) is desirable. The coating amount at the time of drying is preferably about 1.5 to 3.5 g / m ² from the viewpoint of adhesive strength.

  Examples of the present invention will be specifically described below.

As a biaxially stretched polyester film, −20 ° C., 0 ° C., +40 when dynamic viscoelasticity measurement is performed under the measurement conditions of a frequency of 1 Hz, a temperature increase rate of 2 ° C./min, and a measurement temperature range of −150 ° C. to + 150 ° C. The storage elastic modulus (E ′) at ℃ was 4.6 × 10 ⁹ , 4.5 × 10 ⁹ and 4.5 × 10 ⁹ Pa, respectively, and the peak temperature of β transition tan δ was recognized at 0.6 ° C. An anchor coating solution 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. A coat layer was laminated. Thereafter, curing was performed at 50 ° C. for 2 days to promote adhesion of the anchor coat layer.

  Subsequently, a transparent gas barrier vapor deposition layer made of aluminum oxide having a thickness of 15 nm was laminated on the surface of the anchor coat layer of the biaxially stretched polyester film on which the anchor coat layer was laminated, by a vacuum vapor deposition apparatus using an electronic heating wire system.

  Furthermore, 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 polyester film 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 transparent gas barrier laminate of the present invention was prepared.

<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, the transparent gas barrier laminate of the present invention was used in the same manner as in Example 1 except that aluminum oxide having a thickness of 12 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. It was created.

In order to compare the performance of the transparent gas barrier laminate of the present invention, in Example 1, dynamic viscoelasticity was measured under the measurement conditions of a frequency of 1 Hz, a temperature increase rate of 2 ° C./min, and a measurement temperature range of −150 ° C. to + 150 ° C. The storage elastic moduli (E ′) at −20 ° C., 0 ° C., and + 40 ° C. were 5.8 × 10 ⁸ , 5.1 × 10 ⁸ , and 4.9 × 10 ⁸ Pa, respectively, and β A transparent gas barrier laminate as a comparative example was prepared in the same manner as in Example 1 except that a biaxially stretched polyester film in which the peak temperature of the transition tan δ was not observed was used.

  In order to compare the performance of the transparent gas barrier laminate of the present invention, in Example 1, a biaxially stretched nylon film having a thickness of 15 μm was used instead of the biaxially stretched polyester film. A transparent gas barrier laminate as a comparative example was prepared.

  The transparent gas barrier laminates obtained in Examples 1 to 4 were evaluated by performing an oxygen transmission rate, a water vapor transmission rate, a laminate strength, a bag drop test, and a bent pinhole test based on the evaluation methods described below. The evaluation results are shown in Table 1.

  Using the transparent gas barrier laminates obtained in Examples 1 to 4, a 100 mm × 150 mm four-side seal pouch was prepared, and after filling with 150 g of distilled water as the contents, it was 95 minutes 60 minutes in a boil tank. Sterilization treatment was performed.

<Measurement of oxygen permeability>
After the sterilization treatment, the oxygen permeability after standing overnight was measured. The measuring method was based on the measuring condition of 30 degreeC70% RH by OXTRAN2 / 20 made from Modern Control based on JISK-7126B method.

<Measurement of water vapor transmission rate>
The water vapor transmission rate after standing overnight after the sterilization treatment was measured. The measurement method was measured under the measurement conditions of 40 ° C. and 90% RH using PEKMATRAN 3/31 manufactured by Modern Control in accordance with JIS K-7129B method.

<Measurement of laminate strength>
Immediately after the above-described sterilization treatment, measurement was performed using a tensile tester manufactured by Orientec Corporation under the measurement conditions of a test piece width of 15 mm, T-type peeling, and peeling speed of 300 mm / min.

<Falling bag test>
Fifteen four-side seal pouches filled with 150 g of distilled water as the above contents were prepared, dropped 10 times from a height of 1 m, and the number of broken bags was checked.

<Bending pinhole test>
The number of pinholes after the transparent gas barrier laminate obtained in Examples 1 to 4 was bent 2000 times in a room temperature atmosphere by a gelbo flex tester was checked.

なお、表１には、加工適性、総合評価についても記してある。

Table 1 also shows processability and comprehensive evaluation.

  From Table 1, the transparent gas barrier laminate of the present invention has a small decrease in oxygen and water vapor gas burr properties after boil sterilization, and the laminate strength is sufficiently maintained even after sterilization. Further, the biaxially stretched nylon used in Example 4 as a comparative example for comparing the performance of the transparent gas barrier laminate of the present invention with respect to the number of broken bags in the bag drop test and the number of bent pinholes by the gelboflex tester. The transparent gas barrier laminate using the specific polyester film of the present invention as a base material, which exhibits almost the same performance as a film, is particularly excellent in impact resistance and pinhole resistance.

  On the other hand, as a comparative example for comparing with the performance of the transparent gas barrier laminate of the present invention, the transparent gas barrier laminate of Examples 3 and 4 is firstly the transparent gas barrier laminate obtained in Example 3. Although the body has a small decrease in oxygen and water vapor gas burr properties after boil sterilization treatment, and the laminate strength is sufficiently maintained even after sterilization treatment, the number of broken bags and the number of bent pinholes by gelboflex tester Many of them are inferior in impact resistance and pinhole resistance. On the other hand, the transparent gas barrier laminate obtained in Example 4 has a small number of broken bags in the bag drop test and a small number of bent pinholes by the gelboflex tester, but the oxygen and water vapor gas burr properties after the boil sterilization treatment are significantly reduced. Was recognized. Furthermore, the biaxially stretched nylon film constituting the transparent gas barrier laminate obtained in Example 4 has the film stored in a roll shape due to the essential properties of the nylon film having a large water absorption rate and humidity swelling coefficient. When used, the flatness was poor, and there was a difficulty in processing suitability such as vapor deposition, printing and laminating.

It is sectional drawing which shows an example of a structure of the transparent gas barrier laminated body of this invention.

Explanation of symbols

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

Claims (4)

On a specific polyester film substrate, at least an anchor coat layer, a transparent gas barrier vapor deposition layer made of an inorganic oxide, a gas barrier coating layer, a transparent gas barrier laminate formed by sequentially laminating a heat sealable resin film,
The specific polyester film has a storage elastic modulus (E ′) at −20 to + 40 ° C. in the range of 9 × 10 ⁸ to 1 × 10 ¹⁰ Pa and a β transition tan δ peak temperature of + 10 ° C. or lower. A transparent gas barrier laminate having a dynamic viscoelasticity.   2. The transparent gas barrier laminate 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 transparent gas barrier laminate according to claim 1 or 2, wherein a coating agent is applied and dried by heating.   The transparent gas barrier laminate according to any one of claims 1 to 3, wherein the anchor coat layer is composed of a composite of an acrylic polyol, an isocyanate compound, and a silane coupling agent.

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