JP2015150807A - polyester laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester laminate that is excellent in productivity and economical efficiency and has excellent gas barrier property even under a high humidity condition.SOLUTION: The laminate comprises a gas barrier layer (II) laminated on a polyester substrate (I). The polyester substrate (I) contains a metal compound by 0.1 to 70 mass%; and a polyester resin constituting the polyester substrate (I) comprises a polybutylene terephthalate (modified PBT) containing 5 to 20 mass% of a polytetramethylene glycol unit having a molecular weight of 600 to 4000, and polyethylene terephthalate (PET) in a mass ratio of PET/(modified PBT) ranging from 70/30 to 95/5. The gas barrier layer (II) comprises a polycarboxylic acid and polyvinyl alcohol.

Description

  The present invention relates to a polyester laminate having tearing linearity and excellent gas barrier properties even under high humidity.

  Tear linear films (hereinafter referred to as “tear linear films”) having tear linearity in at least one direction include pharmaceutical products including confectionery, pickles, miso, soup, jam, frozen foods, refrigerated foods, retort pouches, etc. It is widely used as a packaging material for everyday products and cosmetics. For example, Patent Document 1 discloses a tearing linear film made of polybutylene terephthalate and polyethylene terephthalate containing a specific polytetraethylene glycol.

  In recent years, tearing linear films have been required to have gas barrier properties so that the contents are not altered during long-term storage. Especially in packaging of foods containing moisture, gas barriers under high humidity are required. Sex is needed.

  As a method for imparting a gas barrier property to a plastic substrate, for example, in Patent Document 2, a laminate comprising a plastic substrate, a gas barrier layer, and a polymer layer containing a divalent or higher-valent metal compound is heated in the presence of water. A method of processing is described.

  However, in the method of Patent Document 2, after forming a gas barrier layer, pressure treatment using an autoclave is performed in water containing a metal compound, and it is difficult to carry out continuously, resulting in poor productivity. It was a thing. In Patent Document 2, a solvent-based paint is applied on a plastic substrate and dried to form an undercoat layer, and then a water-based paint is applied and dried to form a gas barrier layer. Therefore, the method of Patent Document 2 has a problem in terms of economy and productivity, for example, an explosion-proof facility is required to use a solvent-based paint, and multiple applications are required.

JP 11-302405 A JP 2004-322626 A

  An object of the present invention is to solve the above problems, and to provide a polyester laminate having tearing linearity and excellent gas barrier properties even under high humidity.

  As a result of intensive studies on the above problems, the present inventor is excellent even under high humidity by laminating a gas barrier layer containing a polycarboxylic acid on a tear linear polyester film containing a specific amount of a metal compound. As a result, the present inventors have found that gas barrier properties are exhibited.

That is, the gist of the present invention is as follows.
(1) A laminate in which a gas barrier layer (II) is laminated on a polyester substrate (I), the polyester substrate (I) contains 0.1 to 70% by mass of a metal compound, and a polyester substrate ( The polyester resin constituting I) is composed of polybutylene terephthalate (modified PBT) containing 5 to 20% by mass of a polytetramethylene glycol unit having a molecular weight of 600 to 4000 and polyethylene terephthalate (PET), and PET / modified PBT = 70. / 30-95 / 5 (mass ratio), and gas barrier layer (II) contains polycarboxylic acid, The polyester laminated body characterized by the above-mentioned.
(2) The polyester laminate according to (1), wherein the gas barrier layer (II) contains polyvinyl alcohol.
(3) The polyester laminate according to (1) or (2), wherein the metal constituting the metal compound is one kind selected from magnesium, calcium, and zinc.
(4) After hot water treatment at 95 ° C. for 30 minutes, the oxygen permeability in an atmosphere at 20 ° C. and a relative humidity of 65% is 300 mL / (m ² · day · MPa) or less (1 )-(3) The polyester laminated body in any one.
(5) The polyester laminate according to any one of (1) to (4), which is simultaneously or sequentially biaxially stretched.
(6) A packaging bag comprising the polyester laminate according to any one of (1) to (5).

ADVANTAGE OF THE INVENTION According to this invention, the polyester laminated body which is excellent in productivity and economical efficiency, has tearing linearity, and has the gas barrier property excellent also in the high humidity can be provided.
Moreover, the polyester base material containing a metal compound in this invention can be manufactured only by adding a metal compound to the raw material of a polyester base material. Regarding the gas barrier, the step of laminating a layer containing a metal compound, which has been conventionally performed, on a substrate can be omitted. Therefore, a polyester laminate can be obtained with a smaller number of processes than before, and therefore, industrial merit is extremely large from the viewpoint of productivity and cost.

The shape of the test piece used for tear linearity evaluation is shown. The shape of the test piece after tearing linearity evaluation is shown. (A) is an example of a sample with good tear linearity, and (b) is an example of a sample with poor tear linearity.

Hereinafter, the present invention will be described in detail.
The polyester laminate of the present invention is obtained by laminating a gas barrier layer (II) on a polyester substrate (I), and the polyester substrate (I) contains a metal compound.

  The metal constituting the metal compound is not particularly limited, and monovalent metals such as lithium, sodium, potassium, rubidium, and cesium, and magnesium, calcium, zirconium, zinc, copper, cobalt, iron, nickel, aluminum, and the like. A bivalent or higher metal is mentioned. Among them, a metal having a high ionization tendency is preferable from the viewpoint of easy reaction with carboxylic acid, and a monovalent or divalent metal is preferable from the viewpoint of gas barrier properties. Specifically, lithium, sodium, potassium, magnesium, calcium, and zinc are preferable, and magnesium, calcium, and zinc are more preferable. These may be used alone or in combination.

  In the present invention, the metal compound is a compound containing the above metal, and examples of the compound include oxides, hydroxides, halides, inorganic salts such as carbonates, bicarbonates, phosphates, sulfates, Examples thereof include carboxylate such as acetate, formate, stearate, citrate, malate, and maleate, and organic acid salt such as sulfonate, and is preferably an oxide or carbonate. . Moreover, you may use a metal simple substance as a metal compound.

  Among the above metal compounds, preferred examples include lithium carbonate, sodium hydrogen carbonate, magnesium oxide, magnesium carbonate, magnesium hydroxide, magnesium acetate, calcium oxide, calcium carbonate, calcium hydroxide, calcium chloride, calcium phosphate, calcium sulfate, acetic acid. Calcium, zinc acetate, zinc oxide, zinc carbonate, etc. can be mentioned. From the viewpoint of gas barrier properties, magnesium salts such as magnesium oxide, magnesium carbonate, magnesium hydroxide, magnesium acetate, calcium carbonate, calcium acetate, zinc oxide, A divalent metal compound such as zinc acetate is preferable. From the viewpoint of the transparency of the polyester base (I), a monovalent compound such as lithium carbonate or sodium hydrogen carbonate, magnesium oxide, magnesium carbonate, magnesium hydroxide, etc. Magnesium salts are preferred. These may be used alone or in combination.

  The metal compound is preferably in a powder form, and the average particle diameter is not particularly limited, but is preferably 0.001 to 10.0 μm, more preferably 0.005 to 5.0 μm, and 0 0.01 to 2.0 μm is more preferable, and 0.05 to 1.0 μm is particularly preferable. Since the haze of the polyester substrate (I) can be reduced, the metal compound preferably has a smaller average particle size. However, a metal compound having an average particle size of less than 0.001 μm has a large surface area, so that it easily aggregates, and coarse aggregates are scattered in the film, which may deteriorate the mechanical properties of the substrate. On the other hand, the polyester base material (I) containing a metal compound having an average particle size exceeding 10.0 μm tends to be broken when the film is formed, and the productivity tends to decrease.

  A metal compound can improve dispersibility, weather resistance, wettability with a thermoplastic resin, heat resistance, transparency, and the like by performing surface treatment such as inorganic treatment or organic treatment. Examples of the inorganic treatment include alumina treatment, silica treatment, titania treatment, zirconia treatment, tin oxide treatment, antimony oxide treatment, and zinc oxide treatment. Examples of the organic treatment include treatment using a fatty acid compound, a polyol compound such as pentaerythritol and trimethylolpropane, an amine compound such as triethanolamine and trimethylolamine, a silicone compound such as a silicone resin and alkylchlorosilane. .

  The content of the metal compound in the polyester substrate (I) is required to be 0.1 to 70% by mass, preferably 0.1 to 50% by mass, and 0.2 to 20% by mass. It is more preferable that it is 1-5 mass%. From the viewpoint of haze, it is preferably less than 5% by mass. When the content of the metal compound in the polyester substrate (I) is 0.1 to 70% by mass, the obtained polyester laminate can obtain excellent gas barrier properties. However, when the content of the metal compound in the polyester substrate (I) is less than 0.1% by mass, the cross-linked structure formed by reacting with the polycarboxylic acid of the gas barrier layer (II) is reduced and obtained. The gas barrier property of the polyester laminate decreases. On the other hand, the polyester base material (I) having a content exceeding 70% by mass has a high frequency of breaking in stretching during film formation, and the productivity tends to be lowered, and the mechanical properties are also likely to be lowered.

  The method for incorporating the metal compound into the polyester substrate (I) is not particularly limited, and can be blended at an arbitrary point in the production process. For example, a method of adding a metal compound when polymerizing a thermoplastic resin constituting the polyester substrate (I), a method of kneading a thermoplastic resin and a metal compound with an extruder, a high concentration of the metal compound Examples thereof include a method (master batch method) in which a master batch mixed by kneading is prepared, and this is added to a thermoplastic resin and diluted. In the present invention, the master batch method is preferably employed.

  In the present invention, the polyester resin used for the polyester substrate (I) is a polybutylene terephthalate containing a polytetramethylene glycol unit (hereinafter sometimes abbreviated as “PTMG”) (hereinafter abbreviated as “modified PBT”). And polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”).

  The polyester resin is obtained by a known production method, that is, an ester exchange reaction method from dimethyl terephthalate and ethylene glycol, or a direct esterification method from terephthalic acid and ethylene glycol, followed by melt polymerization, or further It can be obtained by solid phase polymerization. The polyester resin may contain other copolymerization components as long as the effects of the present invention are not impaired.

  Other copolymer components include oxalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid , Maleic anhydride, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, dicarboxylic acids such as cyclohexanedicarboxylic acid, 4-hydroxybenzoic acid, ε-caprolactone, oxycarboxylic acids such as lactic acid, 1,3-propane Diol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, cyclohexanedimethanol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol and other glycols, bisphenol A and bisphenol And polyfunctional compounds such as trimellic acid, trimesic acid, pyromellitic acid, trimethylolpropane, glycerin, pentaerythritol, and the like.

  The molecular weight of PTMG used for the polyester resin needs to be 600 to 4000, preferably 1000 to 3000, and more preferably 1000 to 2000. When the molecular weight of PTMG is less than 600, the tear linearity decreases. On the other hand, when the molecular weight of PTMG exceeds 4000, the mechanical strength, dimensional stability, haze and other performances are deteriorated, and stable tear linearity is not exhibited.

  The content of the PTMG unit constituting the modified PBT needs to be 5 to 20% by mass, preferably 10 to 20% by mass, and more preferably 10 to 15% by mass. When the PTMG content is less than 5% by mass, the resulting polyester laminate does not exhibit tear linearity, and when it exceeds 20% by mass, the resulting polyester laminate has mechanical strength, dimensional stability, haze, etc. The performance deteriorates, and it becomes difficult to obtain a stable tear linearity of the polyester laminate. On the other hand, when the content of PTMG exceeds 20% by mass, a phenomenon that pulsates at the time of extrusion (so-called ballast phenomenon) may be manifested particularly when produced on a mass production scale, resulting in increased thickness spots.

  The modified PBT can be obtained by adding PTMG and polycondensation in the PBT polymerization step, but as a simpler method, it can also be obtained by melt-kneading PBT and PTMG with an extruder.

  The mass ratio of PET to modified PBT must be PET / modified PBT = 70/30 to 95/5, preferably 80/20 to 90/10, and 85/15 to 90/10. More preferably. When the mass ratio of the modified PBT to the total of PET and the modified PBT is less than 5% by mass, tear linearity cannot be obtained. On the other hand, when the mass ratio exceeds 30% by mass, mechanical strength, dimensional stability, haze, and other performances are degraded, causing problems in practical performance, and thickness irregularities are increased, and tear linearity is also degraded. .

The polyester base (I) used in the present invention is obtained by stretching a mixture of PBT copolymerized with PTMG having a specific molecular weight and PET at a specific ratio. In the polyester substrate (I), the modified PBT is preferably dispersed in a long island shape in the longitudinal direction in the PET, and the average value in the longitudinal direction of the dispersed particle cross section of the modified PBT observed on the longitudinal section. L (μm), D (μm), the average value of the length in the width direction of the cross section of the modified PBT dispersed particles observed on the cross section in the width direction, and the dispersion of the modified PBT particles observed on the cross section in the width direction. When the number is N (pieces / μm ² ), it is preferable that the following expressions (1) and (2) are satisfied.
10 ≦ L / D ≦ 500 (1)
5 ≦ N ≦ 200 (2)

  Formula (1) shows that the shape of the dispersed particles of the modified PBT is a long bar in the longitudinal direction, and the ratio of the length in the longitudinal direction to the width direction (L / D) is 10 to 500, When it is preferably 50 to 200, it has excellent longitudinal tear linearity. If the L / D of the modified PBT particles is less than 10, the shape anisotropy may be too small and the tear linearity may be deteriorated. If the L / D exceeds 500, the particle shape is disturbed, and the modified PBT particles In some cases, the linear orientation of the film becomes difficult, and displacement may occur during tearing.

Formula (2) shows the number of dispersed modified PBT particles present in the PET, and it is preferably 5 to 200 / μm ² . When the number of dispersed modified PBT particles is less than 5 / μm ^2, tear linearity may not be obtained. On the other hand, when it exceeds 200 particles / μm ² , the inter-particle distance of the modified PBT particles becomes too short, so that the tearing direction is dispersed and misalignment is likely to occur during tearing.

  Other thermoplastic resins such as polyethylene naphthalate and polycyclohexylene dimethylene terephthalate may be mixed with the polyester base material (I) within the range not impairing the effects of the present invention. In addition, UV absorbers, antioxidants, antistatic agents, surfactants, pigments, fluorescent brighteners, etc., organic particles such as silica, calcium carbonate, titanium oxide, etc., acrylic acid, styrene, etc. Particles may be appropriately contained as necessary.

  The polyester substrate (I) may be subjected to surface treatment by corona discharge treatment, surface hardening treatment, plating treatment, coloring treatment, or various coating treatments.

  The polyester substrate (I) may be a single-layer film or a multi-layer film. When the polyester substrate (I) is a multilayer film, it is necessary to contain 0.1 to 70% by mass of the metal compound. Hereinafter, a layer containing a metal compound or a single layer film in the multilayer film is abbreviated as “metal-containing layer (M)”, and layers other than the “metal-containing layer (M)” in the multilayer film are referred to as “resin layer ( R) ”in some cases.

  When the polyester substrate (I) is a multilayer film, the structure of the resulting polyester laminate is such that the gas barrier layer (II) and the metal-containing layer (M) of the polyester substrate (I) are in contact with each other. (R) / (M) / (II), (M) / (R) / (M) / (II), (II) / (M) / (R) / (M) / (II), etc. Is mentioned. Since these structures are such that the gas barrier layer (II) and the metal-containing layer (M) are in contact with each other, the polycarboxylic acid in the gas barrier layer (II) and the metal compound in the metal-containing layer (M) are likely to react. Gas barrier properties can be obtained efficiently. Among these, in consideration of equipment for manufacturing and operability, the configuration of (R) / (M) / (II) is preferable. Further, the gas barrier layer (II) and the resin layer (R) of the polyester base (I) are in contact with each other, (M) / (R) / (II) and (R) / (M) / (R) / (II), (II) / (R) / (M) / (R) / (II) and the like. Among these, the structure of (M) / (R) / (II) is preferable in consideration of equipment for manufacturing and operability.

  The thickness constitution ratio of the metal-containing layer (M) and the resin layer (R) constituting the multilayer film is not particularly limited, and the total thickness (Mt) of the metal-containing layer (M) and the total of the resin layer (R). The ratio of thickness (Rt) ((Rt) / (Mt)) is preferably 1/1000 to 1000/1, and the thickness control of each layer is easy, so 1/100 to 100/1. More preferably, it is more preferably 1/10 to 10/1.

  The above-mentioned additives may be added to the thermoplastic resin constituting the resin layer (R), and the resin layer (R) which is the outermost layer of the polyester laminate is made of silica or the like for the purpose of improving the slip property. Is preferably added.

  The gas barrier layer (II) constituting the polyester laminate of the present invention needs to contain a polycarboxylic acid. The polycarboxylic acid in the gas barrier layer (II) can exhibit gas barrier properties by reacting with the metal compound in the polyester substrate (I).

  The polycarboxylic acid in the present invention is a compound or polymer having two or more carboxyl groups in the molecule, and these carboxyl groups may form an anhydride structure. Specific examples of the polycarboxylic acid include 1,2,3,4-butanetetracarboxylic acid, polyacrylic acid, polymethacrylic acid, acrylic acid-methacrylic acid copolymer, acrylic acid-maleic acid copolymer, polymaleic acid Examples thereof include olefin-maleic acid copolymers such as ethylene-maleic acid copolymers, polysaccharides having carboxyl groups in the side chains such as alginic acid, polyamides containing carboxyl groups, and polyesters. The said polycarboxylic acid may be used independently and may be used together.

  When the polycarboxylic acid is a polymer, the weight average molecular weight is preferably 1000 to 1000000, more preferably 10000 to 150,000, and further preferably 15000 to 110000. If the weight average molecular weight of the polycarboxylic acid is too low, the resulting gas barrier layer (II) becomes fragile. On the other hand, if the molecular weight is too high, the handling properties are impaired, and in some cases, the gas barrier layer (II) described later is used. The gas barrier layer (II) obtained by agglomeration in the coating liquid for forming may have a gas barrier property impaired.

  In the present invention, among the above polycarboxylic acids, polyacrylic acid and olefin-maleic acid copolymers, particularly ethylene-maleic acid copolymers (hereinafter sometimes abbreviated as “EMA”) have gas barrier properties. From the viewpoint, it is preferably used. EMA is obtained by polymerizing maleic anhydride and ethylene by a known method such as solution radical polymerization. The maleic acid unit in the olefin-maleic acid copolymer tends to have a maleic anhydride structure in which the adjacent carboxyl group is dehydration-cyclized in a dry state, and opens to form a maleic acid structure when wet or in an aqueous solution. Therefore, in the present invention, unless otherwise specified, maleic acid units and maleic anhydride units are collectively referred to as maleic acid units. The maleic acid unit in EMA is preferably 5 mol% or more, more preferably 20 mol% or more, further preferably 30 mol% or more, and most preferably 35 mol% or more. . Moreover, it is preferable that the weight average molecular weights of EMA are 1000-1 million, It is more preferable that it is 3000-500000, It is further more preferable that it is 7000-300000, It is especially preferable that it is 10000-200000.

  In the present invention, the gas barrier layer (II) preferably contains a polyalcohol. By containing the polyalcohol, the polycarboxylic acid in the gas barrier layer (II) reacts with the polyalcohol in addition to reacting with the metal compound in the polyester base material (I), thereby improving the gas barrier property. be able to. Polyalcohol is a compound having two or more hydroxyl groups in the molecule. Examples of low molecular weight compounds include sugar alcohols such as glycerin and pentaerythritol, monosaccharides such as glucose, disaccharides such as maltose, and oligosaccharides such as galactooligosaccharide. Examples of the polymer compound include polysaccharides such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and starch. The said polyalcohol may be used independently and may be used together. The saponification degree of polyvinyl alcohol or ethylene-vinyl alcohol copolymer is preferably 95 mol% or more, and more preferably 98 mol% or more. Moreover, it is preferable that average polymerization degree is 50-2000, and it is more preferable that it is 200-1000.

  The polycarboxylic acid and the polyalcohol in the gas barrier layer (II) are preferably contained so that the molar ratio of OH group to COOH group (OH group / COOH group) is 0.01-20. It is more preferable to contain so that it may become 01-10, It is more preferable to contain so that it may become 0.02-5, It is most preferable to contain so that it may become 0.04-2.

  In the present invention, the gas barrier layer (II) preferably contains polyacrylamide, polymethacrylamide or polyamine. By containing these compounds, the polycarboxylic acid in the gas barrier layer (II) reacts with these compounds in addition to reacting with the metal compound in the polyester substrate (I). Can be improved.

  The polyamine has two or more amino groups selected from primary and secondary as amino groups in the molecule. Specific examples thereof include polyallylamine, polyvinylamine, branched polyethyleneimine. And polysaccharides having an amino group in the side chain such as linear polyethyleneimine, polylysine and chitosan, and polyamides having an amino group in the side chain such as polyarginine. The weight average molecular weight of the polyamine is preferably 5,000 to 150,000. If the weight average molecular weight of the polyamine is too low, the resulting gas barrier layer (II) becomes fragile. On the other hand, if the molecular weight is too high, handling properties are impaired, and in some cases, a gas barrier layer (II) described later is formed. Therefore, the gas barrier layer (II) obtained by agglomeration in the coating liquid may have a gas barrier property impaired.

  The mass ratio of polyamine to polycarboxylic acid (polyamine / polycarboxylic acid) in the gas barrier layer (II) is preferably 12.5 / 87.5 to 27.5 / 72.5. If the mass ratio of the polyamine is lower than this, the crosslinking of the carboxyl group of the polycarboxylic acid becomes insufficient. Conversely, if the mass ratio of the polyamine is higher than this, the crosslinking of the amino group of the polyamine becomes insufficient. Moreover, the obtained polyester laminate may be inferior in gas barrier properties.

  The gas barrier layer (II) in the present invention may contain a crosslinking agent. By containing a cross-linking agent, gas barrier properties can be enhanced. The content of the crosslinking agent in the gas barrier layer (II) is preferably 0.1 to 30 parts by mass and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polycarboxylic acid.

  Examples of the crosslinking agent include a compound having self-crosslinking property and a compound having a plurality of functional groups that react with a carboxyl group in the molecule. When the gas barrier layer (II) contains a polyalcohol, it reacts with a hydroxyl group. A compound having a plurality of functional groups in the molecule may also be used. Preferable examples of the crosslinking agent include isocyanate compounds, melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, zirconium salt compounds such as zirconium ammonium carbonate, metal alkoxides, and the like. These crosslinking agents may be used alone or in combination.

  A metal alkoxide is a compound containing a metal to which an alkoxy group is bonded, and an alkyl group substituted with a functional group having reactivity with a halogen or a carboxyl group may be bonded instead of a part of the alkoxy group. . Here, the metal includes atoms such as silicon, aluminum, titanium, and zirconium, the halogen includes chlorine, iodine, bromine, and the like, and the functional group having reactivity with a carboxyl group is an epoxy group. , Amino group, isocyanate group, ureido group and the like, and alkyl group includes methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group and the like. Examples of such compounds include tetramethoxysilane, tetraethoxysilane, chlorotriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, Alkoxysilane compounds such as 3-aminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, alkoxytitanium compounds such as tetraisopropoxytitanium and tetraethoxytitanium, alkoxy such as triisopropoxyaluminum Examples include aluminum compounds and alkoxyzirconium compounds such as tetraisopropoxyzirconium.

  These metal alkoxides must be partially or wholly hydrolyzed, partially hydrolyzed or condensed, fully hydrolyzed and partially condensed, or a combination of these. You can also.

  When the above metal alkoxide and polycarboxylic acid are mixed, it may be difficult for both to react and to be applied. Therefore, it is preferable to form a hydrolysis condensate in advance before mixing. As a method for forming the hydrolysis-condensation product, a method used in a known sol-gel method can be applied.

  The gas barrier layer (II) in the present invention has a heat stabilizer, an antioxidant, a reinforcing material, a pigment, an anti-degradation agent, a weather resistance, as long as the gas barrier property and the adhesion to the polyester substrate (I) are not greatly impaired. An agent, a flame retardant, a plasticizer, a release agent, a lubricant, an antiseptic, an antifoaming agent, a wetting agent, a viscosity modifier, and the like may be added.

  Examples of the heat stabilizer, antioxidant, and deterioration inhibitor include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like. May be.

  Examples of the reinforcing material include clay, talc, wollastonite, silica, alumina, calcium silicate, sodium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, zeolite, montmorillonite, hydrotalcite, fluorine mica, Examples include metal fibers, metal whiskers, ceramic whiskers, potassium titanate whiskers, boron nitride, graphite, glass fibers, carbon fibers, fullerenes (C60, C70, etc.), carbon nanotubes, and the like.

  In the present invention, the thickness of the gas barrier layer (II) laminated on the polyester substrate (I) is preferably thicker than 0.05 μm in order to sufficiently enhance the gas barrier property of the laminate, from the viewpoint of economy. Preferably it is thinner than 5.0 μm.

  The gas barrier layer (II) in the present invention can be formed by applying and drying a coating liquid for forming the gas barrier layer (II) on the polyester substrate (I). Since the coating liquid is preferably aqueous from the viewpoint of workability, the polycarboxylic acid, polyalcohol and polyamine constituting the coating liquid are preferably water-soluble or water-dispersible, and water-soluble. It is more preferable that

  In the present invention, when an aqueous coating solution is prepared by mixing a polycarboxylic acid and a polyalcohol, it is preferable to add 0.1 to 20 equivalent% of an alkali compound with respect to the carboxyl group of the polycarboxylic acid. . Since polycarboxylic acid has high hydrophilicity when the content of carboxyl group is large, it can be made into an aqueous solution without adding an alkali compound. However, the gas barrier property of the obtained polyester laminate can be remarkably improved by adding an appropriate amount of an alkali compound. The alkali compound only needs to be capable of neutralizing the carboxyl group of the polycarboxylic acid, and the addition amount thereof is preferably 0.1 to 20 mol% with respect to the carboxyl group of the polycarboxylic acid.

  The coating liquid can be prepared by a known method using a melting pot equipped with a stirrer. For example, a polycarboxylic acid and a polyalcohol are separately made into aqueous solutions and mixed before coating. The method is preferred. At this time, if the alkali compound is added to the aqueous solution of the polycarboxylic acid, the stability of the aqueous solution can be improved.

  Moreover, in this invention, when mixing polycarboxylic acid and polyamine and preparing an aqueous coating liquid, in order to suppress gelatinization, it is preferable to add a base to polycarboxylic acid. The base is not particularly limited as long as it does not inhibit the gas barrier property of the obtained polyester laminate, and examples thereof include inorganic substances such as sodium hydroxide and calcium hydroxide, and organic substances such as ammonia, methylamine and diethanolamine, and drying and heat treatment. Since it is easy to volatilize, ammonia is preferable. The addition amount of the base is preferably 0.6 equivalents or more, more preferably 0.7 equivalents or more, and further preferably 0.8 equivalents or more with respect to the carboxyl group of the polycarboxylic acid. . If the amount of the base added is small, the coating solution may gel during coating, and it may be difficult to form the gas barrier layer (II) on the polyester substrate (I).

  The method for applying the coating liquid for forming the gas barrier layer (II) to the polyester substrate (I) is not particularly limited, and is an air knife coater, kiss roll coater, metering bar coater, gravure roll coater, reverse roll coater, dip coater. , Die coater, etc., or a combination of these can be used.

  After the coating liquid for forming the gas barrier layer (II) is applied to the polyester substrate (I), the heat treatment may be performed immediately to form a dry film and the heat treatment at the same time. Heat treatment may be performed after moisture or the like is evaporated by spraying or infrared irradiation to form a dry film. It is preferable to perform the heat treatment immediately after the coating unless there is a particular obstacle to the state of the gas barrier layer (II) and physical properties such as gas barrier properties. It does not specifically limit as a heat processing method, The method of heat-processing in dry atmosphere, such as oven, is mentioned. Considering shortening of the process, it is preferable to stretch the polyester base (I) after applying the gas barrier layer (II) forming coating solution. In any of the above cases, it is preferable that the polyester base material (I) on which the gas barrier layer (II) is formed is subjected to a heat treatment for 5 minutes or less in a heated atmosphere of 100 ° C. or higher.

  When the gas barrier layer (II) contains a polycarboxylic acid and a polyalcohol, it can be affected by their ratio, presence / absence of additive components, content thereof, and the like. The heat treatment temperature cannot be generally specified, but is preferably 100 to 300 ° C, more preferably 120 to 250 ° C, further preferably 140 to 240 ° C, and 160 to 220 ° C. It is particularly preferred. If the heat treatment temperature is too low, the cross-linking reaction between the polycarboxylic acid and the polyalcohol cannot be sufficiently advanced, and it may be difficult to obtain a laminate having sufficient gas barrier properties, while it is too high. In addition, the gas barrier layer (II) and the like may become brittle. The heat treatment time is preferably 5 minutes or less, more preferably from 1 second to 5 minutes, further preferably from 3 seconds to 2 minutes, and particularly preferably from 5 seconds to 1 minute. . If the heat treatment time is too short, the cross-linking reaction cannot proceed sufficiently, and it becomes difficult to obtain a laminate having gas barrier properties. On the other hand, if it is too long, productivity decreases.

  The coating liquid for forming the gas barrier layer (II) applied to the polyester substrate (I) is irradiated with high energy rays such as ultraviolet rays, X-rays, and electron beams as necessary before and after the drying. May be. In such a case, a component that is crosslinked or polymerized by irradiation with high energy rays may be blended.

Since the polyester laminate of the present invention has the above-described configuration, it has excellent gas barrier properties. The laminate treated with hydrothermal treatment at 95 ° C. for 30 minutes was measured under an atmosphere of 20 ° C. and relative humidity 65%. the oxygen ^{permeability, 300mL / (m 2 · day} · MPa) can be less, the oxygen permeability is preferably ^{0.01~300mL / (m 2 · day ·} MPa), 0.01 more preferably ~ 200 mL ^/ a (m 2 · day · MPa) , more preferably a ^{0.01~100mL / (m 2 · day ·} MPa).

  Regarding the transparency of the polyester laminate of the present invention, the haze is preferably 70% or less, more preferably 50% or less, further preferably 30% or less, and particularly preferably 15% or less. Preferably, it is most preferably 10% or less. However, this is not the case because transparency may not be required depending on the application.

  The polyester laminate of the present invention is a sample in which the tear propagation end reaches the short side facing the side where the cut was made when the test of tearing by hand in the longitudinal direction from the cut was performed 10 times in the tear linearity evaluation described later. The number is preferably 8 or more, more preferably 9 or more, and even more preferably 10.

  The polyester laminate of the present invention preferably has a tensile strength of 100 MPa or more, and more preferably 130 MPa or more. If the tensile strength is less than 100 MPa, the mechanical strength is not sufficient, and the piercing strength tends to decrease. In addition, the tensile elongation is preferably 60% or more, and more preferably 80% or more, from the same viewpoint as the tensile strength.

  The polyester laminate of the present invention can be produced by the following method.

  Polyester substrate (I) consisting of a single-layer film, for example, a thermoplastic resin mixed with a metal compound is heated and melted with an extruder and extruded into a film form from a T-die, air knife casting method, electrostatic application It cools and solidifies on the cooling drum rotated by well-known casting methods, such as a casting method, and obtains the film of the polyester base material (I) of an unstretched state.

  In addition, the polyester base material (I) composed of a film having a multilayer structure, for example, heat-melts a thermoplastic resin mixed with a metal compound in the extruder A, and heat-melts the thermoplastic resin in the extruder B, respectively. By superposing two types of melted resins in a die, for example, extruding a film having a two-layer structure of metal-containing layer (M) / resin layer (R) from a T-die, and cooling and solidifying in the same manner as above, It can be obtained in a stretched state.

  By including the metal compound in the polyester base material (I) by such a method, the step of laminating the layer containing the metal compound, which has been conventionally performed, on the base material can be omitted.

  The gas barrier layer (II) forming coating solution is applied to the obtained single-layer or multi-layer unstretched film by the above-described method to form the gas barrier layer (II), and the tenter-type simultaneous biaxial stretching machine is used. By performing simultaneous biaxial stretching in the longitudinal direction and the width direction, it is possible to obtain a laminate that is simultaneously biaxially stretched. In addition, after the obtained unstretched film is stretched in the longitudinal direction, the gas barrier layer (II) forming coating solution is applied by the above-described method to form the gas barrier layer (II), and then stretched in the width direction. Thus, a laminated body sequentially biaxially stretched can be obtained. If the unstretched film is oriented, the stretchability may be lowered in a later step. Therefore, it is preferable that the unstretched film is substantially amorphous and non-oriented.

  The stretching method is not particularly limited, but it is preferable to use a simultaneous biaxial stretching method. In general, the simultaneous biaxial stretching method can have practical characteristics such as mechanical characteristics, optical characteristics, thermal dimensional stability, and pinhole resistance. In addition, in the sequential biaxial stretching method in which the transverse stretching is performed after the longitudinal stretching, the orientation crystallization of the film proceeds during the longitudinal stretching, and the stretchability of the thermoplastic resin during the transverse stretching is reduced, thereby blending the metal compound. When the amount is large, the breaking frequency of the film tends to increase. For this reason, in this invention, it is preferable to perform a water absorption process and to take the simultaneous biaxial stretching method.

  The polyester laminate of the present invention can be treated in a humidified atmosphere after producing the laminate for the purpose of enhancing gas barrier properties. By the humidification treatment, the action of the metal compound of the polyester substrate (I) and the polycarboxylic acid of the gas barrier layer (II) can be further promoted. In such humidification treatment, the laminate may be left in an atmosphere of high temperature and high humidity, or the laminate may be directly contacted with high temperature water. Humidification conditions vary depending on various purposes, but when left in an atmosphere of high temperature and high humidity, a temperature of 30 to 130 ° C. and a relative humidity of 50 to 100% are preferable. Also when making it contact with high temperature water, the temperature of about 30-130 degreeC (100 degreeC or more is under pressure) is preferable. The humidifying treatment time varies depending on the treatment conditions, but generally a range of several seconds to several hundred hours is selected.

  The polyester laminate of the present invention may be subjected to surface treatment such as corona discharge treatment, if necessary.

  The polyester laminate of the present invention can be made into various laminated films by laminating a resin layer such as a sealant.

  The resin used as the sealant is low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, polyethylene / polypropylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid. / Methacrylic acid copolymer, ethylene-acrylic acid / methacrylic ester copolymer, polyvinyl acetate resin, etc., polyethylene, polypropylene, polyethylene / polypropylene copolymer, etc. with high heat seal strength and material strength The polyolefin resin is preferred. These resins may be used alone, or may be copolymerized or melt-mixed with other resins, or may be further acid-modified.

  Examples of a method for forming a sealant layer in a laminate include a method of laminating a film or sheet made of a sealant resin on a laminate via an adhesive, a method of extrusion laminating a sealant resin to a laminate, and the like. . In the former method, the film or sheet made of the sealant resin may be in an unstretched state or in a stretched state at a low magnification, but practically preferably in an unstretched state.

  Although the thickness of a sealant layer is not specifically limited, It is preferable that it is 20-100 micrometers, and it is more preferable that it is 40-70 micrometers.

  A packaging bag can be produced using the polyester laminate of the present invention. This packaging bag is, for example, a food, drink, fruit, juice, drinking water, liquor, cooked food, marine product, frozen food, It can be filled and packed with contents such as meat products, boiled foods, rice cakes, liquid soups, seasonings, other various foods and drinks, liquid detergents, cosmetics, and chemical products.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

1. Measurement Method (1) Average Particle Size A cumulative percent value of 50% in a particle size distribution (volume distribution) curve measured with a laser particle size analyzer “Microtrac HRA” (manufactured by Nikkiso Co., Ltd.) was determined. A sample for measuring the average particle diameter was prepared by adding 50 g of isopropanol to 0.5 g of the metal compound and performing ultrasonic dispersion treatment for 3 minutes.

(2) Thickness of each layer The obtained polyester laminate was allowed to stand in an environment of 23 ° C. and 50% RH for 2 hours or more, and then the film cross-section was observed with a scanning electron microscope (SEM) to measure the thickness of each layer. .

(3) Oxygen permeability After the obtained polyester laminate was hydrothermally treated at 95 ° C. for 30 minutes, it was left in an environment of 23 ° C. and 50% RH for 2 hours or more, and then an oxygen barrier manufactured by Mocon Co., Ltd. Using a measuring instrument (OX-TRAN 2/20), the oxygen permeability was measured in an atmosphere at a temperature of 20 ° C. and a relative humidity of 65%. The unit is mL / (m ² · day · MPa).

(4) Haze Using a Nippon Denshoku haze meter (NDH 4000), the total light transmittance (Tt) and diffuse transmittance (Td) of the laminate are measured in accordance with JIS K 7136. Based on this, the haze was calculated.
Haze (%) = (Td / Tt) × 100

(5) Tear linearity A piece of film having a length of 205 mm in the longitudinal direction and a length of 10 mm in the width direction is cut out from the polyester laminate, and a material having a length of 5 mm is inserted in the center of one short side of the film piece. This was manufactured (FIG. 1), and was torn by hand in the longitudinal direction from the cut. As shown in FIG. 2 (a), when the number of samples that reached the short side facing the side where the tear propagation edge was cut was 8 or more, “◯”, and when the number of samples was 7 or less, “×”.

2. Raw materials The raw materials used in the following examples and comparative examples are as follows.
(1) Polyester substrate (I) Polyester resin mixture / polyester resin mixture A for constitution
194 parts by mass of dimethyl terephthalate, 108 parts by mass of 1,4-butanediol and 80 ppm of tetrabutyl titanate (mass of titanium metal relative to the theoretical amount) were added to the transesterification vessel, and the ester exchange reaction was carried out at 150 to 210 ° C. for 2.5 hours. Went.
The obtained transesterification reaction product was transferred to a polymerization vessel, 40 ppm of tetrabutyl titanate was added, 15% by mass of PTMG was added, pressure reduction was started, and finally, the temperature was 210 to 245 under a reduced pressure of 4 hPa. A modified PBT was obtained by melt polymerization at 2 ° C for 2 hours.
15% by mass of the modified PBT obtained and 85% by mass of PET (polyethylene terephthalate resin, UT-CBR intrinsic viscosity 0.62 manufactured by Unitika) were mixed with chips to obtain a polyester resin mixture A1.
Polyester resin mixture A2, A3, B1, B2, C to H
Polyester resin mixture, except that the amount of monomer used in the modified PBT is changed and polymerization is performed so that the resin composition shown in Table 1 is changed, and the amount of the modified PBT and PET is changed so as to be the mixing ratio shown in Table 1. The same operation as in the production method of A1 was performed to obtain a polyester resin mixture.

(2) Polyester base material (I) Metal compound for constituting MgO: Magnesium oxide (Puremag FNM-G average particle size 0.4 μm, manufactured by Tateho Chemical Co., Ltd.)
MgCO ₃ : Magnesium carbonate (manufactured by Kamishima Chemical Industry Co., Ltd. MSS average particle size 1.2 μm)
-CaCO ₃ : Calcium carbonate (Vigot 15 average particle size 0.5 μm, manufactured by Shiroishi Kogyo Co., Ltd.)
ZnO: Zinc oxide (FINEX-50 average particle size 0.02 μm, manufactured by Sakai Chemical Industry Co., Ltd.)

(3) Polyester substrate (I) Metal compound master chip / chip 1 for construction
A master chip was prepared by kneading 85 parts by mass of the polyester resin mixture A1 and 15 parts by mass of MgO, and used to prepare a metal-containing layer (M) having a metal compound content of 15% by mass or less. .
・ Master chip 2
A master chip was prepared by kneading 25 parts by mass of the polyester resin mixture A1 and 75 parts by mass of MgO, and used to prepare a metal-containing layer (M) in which the content of the metal compound exceeded 15% by mass. .
・ Master chip 3
It was prepared by kneading 85 parts by mass of the polyester resin mixture A1 and 15 parts by mass of MgO.
・ Master chip 4
It was prepared by kneading 85 parts of the polyester resin mixture A1 and 15 parts by weight of MgCO ₃ .
・ Master chip 5
It was prepared by kneading 85 parts of the polyester resin mixture A1 and 15 parts by weight of CaCO ₃ .
・ Master chip 6
It was prepared by kneading 85 masses of the polyester resin mixture A1 and 15 mass parts of ZnO.
・ Master chip 7-16
Master chips 7 to 16 were prepared by kneading 50 parts by mass of polyester resin mixtures A2, A3, B1, B2, and C to H and 50 parts by mass of MgO, respectively.

(4) Polycarboxylic acid component / EMA aqueous solution of gas barrier layer (II) forming coating solution:
EMA (weight average molecular weight 60000) and sodium hydroxide were added to water, dissolved by heating and then cooled to room temperature. 10 mol% of the carboxyl group of EMA was neutralized with sodium hydroxide, solid content 15 Mass% EMA aqueous solution.
-PAA aqueous solution:
10 mol% of the carboxyl group of polyacrylic acid prepared by using polyacrylic acid (A10H manufactured by Toagosei Co., Ltd., number average molecular weight 200,000, 25% by weight aqueous solution) and sodium hydroxide is contained in sodium hydroxide. An aqueous polyacrylic acid (PAA) solution having a solid content of 15% by mass.

(5) Other resin component and PVA aqueous solution of gas barrier layer (II) forming coating solution:
Polyvinyl alcohol (Polyal 105 manufactured by Kuraray Co., Ltd., saponification degree 98 to 99%, average polymerization degree about 500) was added to water, dissolved by heating, and then cooled to room temperature. PVA) aqueous solution.
PAM: polyacrylamide (manufactured by Kishida Chemical Co., Ltd., reagent, weight average molecular weight 9 million to 10 million, polymerization degree 1270 to 141,000).

Example 1
The polyester resin mixture A1 and the metal compound-containing master chip were mixed so that the magnesium oxide content was 1%. This mixture was put into an extruder and melted in a cylinder at 280 ° C. The melt was extruded into a sheet form from a T-die orifice, brought into close contact with a rotating drum cooled to 25 ° C., and quenched to obtain an unstretched polyester substrate (I) film having a thickness of 120 μm.
Next, an EMA aqueous solution and a PVA aqueous solution are mixed so that the mass ratio (solid content) of PVA and EMA is 50/50, and a coating liquid for forming a gas barrier layer (II) having a solid content of 10% by mass. Got. This coating solution was applied to one side of an unstretched film that had been subjected to water immersion treatment, and then dried.
The end of the film was held by a clip of a tenter simultaneous biaxial stretching machine, and stretched 3.3 times in the width direction and the longitudinal direction at 85 ° C. Thereafter, a relaxation rate in the width direction was set to 5%, heat treatment was performed at 220 ° C. for 4 seconds, and the mixture was gradually cooled to room temperature. A polyester base material (I) having a thickness of 12 μm and a gas barrier layer having a thickness of 0.3 μm ( A polyester laminate obtained by laminating II) was obtained.

Examples 2-12, Comparative Examples 1, 3-9
The polyester resin mixture and the master chip were mixed so that the metal compound content described in Tables 2 and 3 was obtained, and the thickness after stretching was adjusted to the thickness described in Tables 2 and 3, In the same manner as in Example 1, an unstretched polyester substrate (I) film was obtained and subjected to water immersion treatment.
Next, for other resins such as PVA and polycarboxylic acids, the gas barrier layer was the same as in Example 1 except that the types and mass ratios (solid contents) were those shown in Tables 2 and 3. (II) A forming coating solution was prepared.
Using the obtained coating solution, the film after stretching was applied to an unstretched film and dried in the same manner as in Example 1 except that the thickness after stretching was as shown in Tables 2 and 3. Stretched to obtain a polyester laminate.

Example 13
A coating solution for forming the gas barrier layer (II) was prepared as follows.
That is, polyacrylic acid (PAA) having a number average molecular weight of 200,000 was dissolved in distilled water to obtain a PAA aqueous solution having a solid content concentration of 13% by mass in the aqueous solution. Subsequently, a 13% by mass aqueous ammonia solution was added to the aqueous PAA solution to neutralize 1 mol% of the carboxyl groups of the PAA, thereby obtaining a partially neutralized aqueous solution of PAA.
Further, 100 parts by mass of polyacrylic acid (PAA) having a number average molecular weight of 40,000 was dissolved in 1064 parts by mass of methanol, and then 166 parts by mass of γ-aminopropyltrimethoxysilane (APTMOS) was added with stirring. In this way, an APTMOS methanol solution (13-1) was obtained. In the APTMOS methanol solution (13-1), at least a part of the amino group of APTMOS is neutralized by the carboxyl group of PAA.
Next, a TMOS methanol solution was prepared by dissolving 34.5 parts by mass of tetramethoxysilane (TMOS) in 34.5 parts by mass of methanol. While maintaining the temperature of this TMOS methanol solution at 10 ° C. or lower, 2.3 parts by weight of distilled water and 5.7 parts by weight of 0.1M hydrochloric acid were added, and hydrolysis and condensation were carried out at 10 ° C. for 60 minutes with stirring. By performing the reaction, a solution (13-2) was obtained.
Subsequently, after the solution (13-2) was diluted with 214.7 parts by mass of methanol and 436.1 parts by mass of distilled water, 235.9 parts by mass of the partially neutralized aqueous solution of PAA was added with stirring. A solution (13-3) was obtained.
Subsequently, 36.2 parts by mass of the APTMOS methanol solution (13-1) was added while stirring the solution (13-3), and the mixture was further stirred for 30 minutes to obtain a solution (13-4).
A polyester laminate was obtained in the same manner as in Example 11 except that the solution (13-4) prepared by the above method was used as the gas barrier layer (II) forming coating solution.

Example 14
The polyester resin mixture A1 and the master chip were mixed so that the magnesium oxide content was 50 parts by mass. This mixture was put into an extruder A and melt-extruded at 280 ° C. On the other hand, the polyester resin mixture A1 was put into an extruder B and melt-extruded at 280 ° C.
The two types of resins melted in the extruder A and the extruder B are overlapped in a die, and a sheet having a two-layer structure of metal-containing layer (M) / resin layer (R) is extruded from the T die, and the surface temperature is 25. An unstretched multi-layer film having a thickness of 120 μm, which is (M) / (R) = 5/115 μm, was obtained by closely adhering to a cooling roll at ° C. The obtained unstretched multilayer film was sent to a 50 ° C. hot water tank and subjected to water immersion treatment for 2 minutes.
Next, the coating liquid prepared in the same manner as in Example 1 was applied to the metal-containing layer (M) surface of the unstretched multilayer film and then dried.
In the same manner as in Example 1, it was subjected to simultaneous biaxial stretching and heat treatment to comprise a metal-containing layer (M) having a thickness of 0.5 μm and a resin layer (R) having a thickness of 11.5 μm, and having a thickness of 12 μm. A polyester laminate in which a gas barrier layer (II) having a thickness of 0.3 μm was laminated on the metal-containing layer (M) of the plastic substrate (I) was obtained.

Examples 15-20, Comparative Examples 10-15
The polyester resin mixture and the master chip are mixed so as to have the composition described in Tables 2 and 3, and the thicknesses of the extruders A and B are adjusted so that the thickness after stretching becomes the thickness described in Tables 2 and 3. An unstretched multilayer film was obtained in the same manner as in Example 14 except that the extrusion amount was changed, and was subjected to water immersion treatment.
Next, with respect to other resins such as PVA and polycarboxylic acids, the gas barrier layer (II) was prepared in the same manner as in Example 1 except that the mass ratio (solid content) was as described in Tables 2 and 3. ) A forming coating solution was prepared.
Using the obtained coating solution, the film after stretching was applied to an unstretched film and dried in the same manner as in Example 1 except that the thickness after stretching was as shown in Tables 2 and 3. Stretched to obtain a polyester laminate.

Example 21
The metal-containing layer (M) having a thickness of 3 μm and the thickness are the same as in Example 14 except that the coating liquid for forming the gas barrier layer (II) is applied to the resin layer (R) surface of the unstretched multilayer film. A polyester laminate in which a gas barrier layer (II) having a thickness of 0.3 μm is laminated on a resin layer (R) of a plastic substrate (I) having a thickness of 15 μm, comprising a resin layer (R) having a thickness of 12 μm. .

Comparative Example 2
An unstretched polyester base film was obtained in the same manner as in Example 1 except that the polyester resin mixture and the master chip were mixed so that the metal-containing layer shown in Table 3 was formed. did.
Next, using the gas barrier layer (II) forming coating solution obtained in Example 1, it was applied to an unstretched film and dried in the same manner as in Example 1, and then it was attempted to simultaneously biaxially stretch. The film was broken during stretching, and a polyester laminate could not be obtained.

  Tables 2 and 3 show the configurations and evaluation results of the polyester laminates obtained in Examples and Comparative Examples.

  The polyester laminates of Examples 1 to 23 all had tearing linearity and excellent gas barrier properties even under high humidity.

Since the polyester laminated body of the comparative example 1 had less than 0.1 mass% of the metal compound contained in the polyester base material (I), the gas barrier property was low.
Since the polyester laminate of Comparative Example 3 did not contain polycarboxylic acid in the gas barrier layer (II), the gas barrier property was low.
In the polyester laminates of Comparative Examples 4 and 10, the PTMG amount of the modified PBT used was less than 5% by mass, so that the tear linearity was poor.
The polyester laminates of Comparative Examples 5 and 11 had poor tear linearity because the blending ratio of the modified PBT amount in the polyester resin mixture used was less than 5% by mass.
In the polyester laminates of Comparative Examples 6 and 12, the blending ratio of the modified PBT amount in the polyester resin mixture to be used exceeded 30% by mass, so that the tear linearity was poor.
In the laminates of Comparative Examples 7 and 13, the PTMG amount of the modified PBT used exceeded 30% by mass, and therefore the tear linearity was poor.
The laminated body of Comparative Example 8 had poor tear linearity because the molecular weight of the PTMG amount of the modified PBT used was less than 600.
The laminated body of Comparative Example 9 had poor tear linearity because the molecular weight of the PTMG amount of the modified PBT used exceeded 4000.

1 notch

Claims (6)

A polyester substrate (I) is laminated with a gas barrier layer (II), the polyester substrate (I) contains 0.1 to 70% by mass of a metal compound, and the polyester substrate (I) The constituting polyester resin is composed of polybutylene terephthalate (modified PBT) containing 5 to 20% by mass of a polytetramethylene glycol unit having a molecular weight of 600 to 4000 and polyethylene terephthalate (PET), and PET / modified PBT = 70/30 to It is 95/5 (mass ratio), and gas barrier layer (II) contains polycarboxylic acid, The polyester laminated body characterized by the above-mentioned. The polyester laminate according to claim 1, wherein the gas barrier layer (II) contains polyvinyl alcohol. The polyester laminate according to claim 1 or 2, wherein the metal constituting the metal compound is one kind selected from magnesium, calcium, and zinc. The oxygen permeability in an atmosphere of 20 ° C and 65% relative humidity after hot water treatment at 95 ° C for 30 minutes is 300 mL / (m ² · day · MPa) or less. The polyester laminated body in any one of. The polyester laminate according to any one of claims 1 to 4, wherein the polyester laminate is simultaneously or sequentially biaxially stretched. A packaging bag comprising the polyester laminate according to any one of claims 1 to 5.