Coating composition for forming gas barrier coating film and gas barrier laminate

Abstract

Provided are: a gas barrier laminate having a gas barrier coating film that has excellent oxygen barrier properties and transparency and also has water vapor barrier properties superior to those of conventional gas barrier coating films; and a coating composition that enables efficient formation of such a gas barrier coating film. The gas barrier laminate has a gas barrier coating film on a substrate and is characterized in that: the gas barrier laminate is free from coloration derived from an organic compound, such as an amine compound or a carboxylic acid compound; the ratio (P / Zr) of the Zr (Zr-Kα) and P (P-Kα) contents in fluorescent X-ray measurement of the coating film is in a range of 1.39-2.59; and the ratio (P2 / P1) of a peak area (P2) in 2600-3700 cm-1 and a peak area (P1) in 850-1350 cm-1 in an infrared absorption spectrum of the coating film is less than 0.772.

Description

Coating composition for forming gas barrier coating film and gas barrier laminate

[0001] The present invention relates to a coating composition for forming a gas barrier coating film and a gas barrier laminate having a coating film made from this coating composition, and more specifically to a gas barrier laminate having a coating film that has excellent oxygen barrier properties and water vapor barrier properties as well as excellent transparency, and a coating composition that can form such a coating film.

[0002] A gas barrier laminate formed by forming a film containing metal atoms and phosphorus atoms as constituent components on a plastic substrate has been known. For example, Patent Document 1 below discloses a composite structure having a substrate (X) and a layer (Y) laminated on the substrate (X), the layer (Y) containing a reaction product (R), the reaction product (R) being a reaction product formed by the reaction of at least a metal oxide (A) and a phosphorus compound (B), and having a viscosity of 800 to 1400 cm －１ The fraction (n) at which the infrared absorption is maximum in the infrared absorption spectrum of the layer (Y) in the range １ ) is 1080-1130 cm －１ and the metal atom (M) constituting the metal oxide (A) is aluminum.

[0003] The composite structure disclosed in Patent Document 1 satisfies both oxygen barrier properties and water vapor barrier properties, but there are concerns about its stability against acids and alkalis contained in the contents. Furthermore, during the drying process of film formation, volatile acids contained in the paint evaporate, which must be addressed, resulting in poor productivity. The present inventors have proposed a coating composition that solves the above problems with a composite structure made of a reaction product of a metal oxide and a phosphate compound, and that, by incorporating specific additives, can exhibit even better oxygen barrier properties and water vapor barrier properties (Patent Document 2).

[0004] In the coating composition for forming a gas barrier coating film according to Patent Document 2, an amine compound containing a polyvalent metal ion and an organic carboxylic acid is used as a specific additive, and the polyvalent metal ion captures the metal ion, and the amine compound reacts with the metal ion, carboxylic acid, and phosphoric acid to be incorporated into a crosslinked structure and function as a binder between metal oxide particles, thereby forming a coating film without defects and enabling the development of better oxygen barrier properties and water vapor barrier properties.

[0005] Furthermore, the present inventors have proposed a coating composition that further improves on the coating composition of Patent Document 2, which contains at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a metal hydroxide, in addition to a metal oxide and a phosphate compound.

[0006] Patent No. 4961054 International Publication No. 2022 / 075352

[0007]

[0009] A coating film made from the above-mentioned coating composition can efficiently form a coating film that has excellent oxygen barrier properties and water vapor barrier properties due to the uniform and dense crosslinked structure of the metal oxide and the phosphate compound, as well as excellent transparency and is free from yellowing due to the reaction between the amine compound and the carboxylic acid, and through further research, the present inventors have found that the water vapor barrier properties can be further improved in a coating film made from the above-mentioned coating composition. Therefore, an object of the present invention is to provide a gas barrier laminate comprising a gas barrier coating film that has excellent oxygen barrier properties and transparency, and water vapor barrier properties that are even better than conventional gas barrier coating films, and a coating composition that can efficiently form such a gas barrier coating film.

[0008] According to the present invention, there is provided a gas barrier laminate having a gas barrier coating film on a substrate, wherein the coating film comprises a reaction product obtained by reacting a metal alkoxide, a hydrolyzate of a metal alkoxide, at least one metal hydroxide, zirconium oxide, and a phosphate compound or a sulfate compound, and the content ratio (P / Zr) of Zr (Zr-Kα) and P (P-Kα) in an X-ray fluorescence measurement of the coating film is in the range of 1.39 to 2.59, and the infrared absorption spectrum of the coating film shows a peak at 2600 to 3700 cm －１The peak area (P2) and 850-1350 cm －１ The gas barrier laminate is characterized in that the ratio (P2 / P1) of the peak areas (P1) of the above peaks is less than 0.772.

[0009] In the gas barrier laminate of the present invention, [1] a biaxially stretched polyethylene terephthalate film having a thickness of 25 μm is used as a substrate, and a coating amount on the substrate is 1.8 to 2.2 g / m ２ [1] The haze of a gas barrier laminate having the coating film formed thereon is less than 9.0%, [2] the metal species of the metal alkoxide, the hydrolyzate of the metal alkoxide, or the metal hydroxide is aluminum, and the content ratio (Al / Zr) of Zr (Zr-Kα) and Al (Al-Kα) in the coating film measured by fluorescent X-rays is in the range of 0.15 to 0.58, [3] the coating film has a wavelength of 1000 to 1120 cm in an infrared absorption spectrum －１ [4] A biaxially oriented polyethylene terephthalate film having a thickness of 25 μm is used as a substrate, and the coating amount formed on the substrate is 1.8 to 2.2 g / m ２ A gas barrier laminate obtained by laminating a biaxially oriented polyethylene terephthalate film having a thickness of 25 μm on the coating film via an adhesive layer has a water vapor permeability of 0.100 g / m ２ It is preferable that the temperature is less than 40°C and 90% RH.

[0010] The present invention also provides a deposition substrate comprising the gas barrier laminate.

[0011] The present invention further provides a coating composition for forming a gas barrier coating film, which contains a metal alkoxide, a hydrolysate of a metal alkoxide, at least one metal hydroxide, a metal oxide, and a phosphoric acid compound or a sulfate compound, wherein the coating composition for forming a gas barrier coating film, when dispersed in water / isopropanol (60 / 40) having a solids content of 5 to 7% by mass, has a viscosity ratio (A / B) of less than 3.6, measured at 25°C using a Brookfield viscometer, where the viscosity (A) is at a spindle rotation speed of 50 rpm and the viscosity (B) is at a spindle rotation speed of 200 rpm.

[0012] In the coating composition for forming a gas barrier coating film of the present invention, [1] the viscosity of the coating composition for forming a gas barrier coating film when dispersed in water / isopropanol (60 / 40) with a solid content of 5 to 7% by mass, measured at a temperature of 25°C using a Brookfield viscometer at a spindle rotation speed of 50 rpm, is less than 113.9 mPa·sec; [2] the metal species of the metal alkoxide or metal hydroxide is at least one of aluminum, titanium, iron, and zirconium; [3] the metal alkoxide is at least one of methoxide, ethoxide, propoxide, isopropoxide, butoxide, isobutoxide, sec-butoxide, and tert-butoxide; [4] the metal alkoxide is aluminum isopropoxide; [5] the metal hydroxide is aluminum hydroxide; [6] the metal oxide is zirconium oxide or aluminum oxide; [7] It is preferable that the metal oxide is a crystalline zirconium oxide, and [8] the phosphoric acid compound is at least one of orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, and cyclic polyphosphoric acid.

[0013] The present invention still further provides a method for producing a coating composition for forming a gas barrier coating film, which comprises mixing a metal alkoxide, a hydrolysate of a metal alkoxide, at least one metal hydroxide, a metal oxide, and a phosphoric acid compound or a sulfate compound, and then stirring the mixture so that the viscosity, measured using a Brookfield viscometer at a temperature of 25°C and a spindle rotation speed of 50 rpm, is less than 113.9 mPa sec.

[0014] In the gas barrier laminate of the present invention, the metal oxide is uniformly and highly dispersed without agglomeration, accelerating the reaction between the metal oxide and the phosphate compound or sulfate compound, forming a uniform and dense crosslinked structure. This inhibits permeation of nonpolar and polar gas molecules, resulting in excellent oxygen and water vapor barrier properties. Furthermore, the amount of unreacted hydroxyl groups in the gas barrier coating film, which serve as pathways for polar gases (water molecules), is reduced, further improving water vapor barrier properties. Furthermore, the suppression of aggregation of the metal oxide particles results in excellent coating film transparency, and a laminate in which a coating film is formed on a 25 μm-thick biaxially oriented polyethylene terephthalate substrate exhibits a haze of less than 9.0%. In the coating composition for forming a gas barrier coating of the present invention, the metal oxide particles are uniformly and highly dispersed without agglomeration, resulting in reduced thixotropy. Therefore, the viscosity is adjusted to be lower than that of conventional coating compositions for forming gas barrier coatings, and the coating film has excellent coatability and leveling properties, making it possible to form a uniform and smooth coating film. In addition, the excellent smoothness of the coating film suppresses light scattering on the coating film surface, which, together with the absence of aggregation of metal oxide particles, reduces the haze of the coating film, resulting in excellent transparency. Furthermore, the excellent coatability reduces the occurrence of coating film defects, and, combined with the formation of a uniform and dense crosslinked structure due to the high dispersion of metal oxide particles as described above, it is possible to form a coating film with excellent oxygen barrier properties and water vapor barrier properties. Furthermore, since the coating material does not contain volatile acids, no measures need to be taken in the drying process, resulting in excellent productivity and safety.

[0015] 1 is a diagram showing the cross-sectional structure of one example of the gas barrier laminate of the present invention, and FIGURE 2 is a diagram showing the cross-sectional structure of another example of the gas barrier laminate of the present invention.

[0016] (Gas Barrier Laminate) In the gas barrier laminate of the present invention, the gas barrier coating film formed on the substrate has a wavelength of 2600 to 3700 cm in an infrared absorption spectrum. －１ The peak area (P2) and 850-1350 cm －１

[0039] An important feature is that the ratio (P2 / P1) of the peak areas (P1) of the peaks (P2 / P1) of the peak areas (P1) of the peaks (P2 / P1) is less than 0.772. The gas barrier coating film in the gas barrier laminate of the present invention can be formed from a coating composition for forming a gas barrier coating film, which contains at least one of a metal alkoxide, a metal alkoxide hydrolysate, and a metal hydroxide, together with a metal oxide and a phosphate compound, etc., as described below, and particularly a coating composition in which the metal oxide is zirconium oxide. Specifically, the gas barrier coating film is formed by crosslinking a metal oxide with a phosphate compound or a sulfate compound to form a metal phosphate or a metal sulfate. Furthermore, metal alkoxides, etc., react with phosphate compounds or sulfate compounds to form metal phosphates or metal sulfates, which are incorporated into the crosslinked structure and function as binders between metal oxide particles. The peak area (P1) in the infrared absorption spectrum is the peak area of ​​a metal phosphate or metal sulfate in FT-IR measurement of a coating film on a substrate, while the peak area (P2) is the peak area of ​​a hydroxyl group in the coating film alone. A ratio of these (P2 / P1) of less than 0.772 means, as mentioned above, that the reaction between the metal oxide and the phosphate compound or the like is efficiently promoted, and a dense crosslinked structure free from defects due to the generation of the metal phosphate or the like is efficiently formed, while the number of unreacted hydroxyl groups is reduced.

[0017] Furthermore, in the gas barrier laminate of the present invention, as described above, the dispersibility of zirconium oxide (hereinafter sometimes referred to as "metal oxide") in the coating film is excellent, so there is no aggregation of zirconium oxide particles (hereinafter sometimes referred to as "metal oxide particles"), and the transparency of the coating film is improved. ２ In the case of a gas barrier laminate having a coating film formed in this coating amount, the haze is less than 9.0%.

[0018] When the gas barrier coating film in the gas barrier laminate of the present invention uses zirconium oxide as the metal oxide, phosphoric acid as the phosphate compound, etc., and aluminum isopropoxide or aluminum hydroxide as the metal alkoxide, etc., it is preferable that the content ratio (Al / Zr) of Zr (Zr-Kα) of zirconium oxide measured by X-ray fluorescence to Al (Al-Kα) of aluminum alkoxide, etc. measured by X-ray fluorescence measurement, is 0.15 or more and less than 0.60, particularly 0.33 to 0.58, and further preferably 0.43 to 0.58. When the content ratio (Al / Zr) is within this range, it is possible to achieve the aforementioned effects of the aluminum alkoxide, etc., without impairing the dense cross-linked structure of the zirconium oxide and the phosphate compound, and it is possible to achieve excellent oxygen barrier property and water vapor barrier property.

[0019] Furthermore, when the gas barrier coating film of the gas barrier laminate of the present invention uses zirconium oxide as the metal oxide, phosphoric acid as the phosphate compound, and aluminum isopropoxide or aluminum hydroxide as the metal alkoxide, it is preferable that the content ratio (P / Zr) of Zr (Zr-Kα) of the zirconium oxide measured by X-ray fluorescence to P (P-Kα) of the phosphate compound measured by X-ray fluorescence is in the range of 1.39 or more and less than 2.68, particularly in the range of 1.49 to 2.59, and even more preferably in the range of 1.91 to 2.59. When the content ratio (P / Zr) is in the above range, the phosphate compound reacts efficiently with the metal oxide in the coating film, neither too much nor too little, resulting in the formation of a uniform and dense coating film that can exhibit excellent oxygen barrier properties and water vapor barrier properties. In other words, if the content ratio measured by X-ray fluorescence is less than the above range and the phosphate compound is insufficient, the metal oxide particles will not bond well together and defects will occur in the coating film structure, which may result in reduced oxygen barrier properties and water vapor barrier properties. On the other hand, if the content ratio determined by fluorescent X-ray measurement is greater than the above range and the amount of phosphate compound is excessive, the amount of hydroxyl groups derived from phosphate groups will increase, which may also result in a decrease in oxygen barrier property and water vapor barrier property.

[0020] The coating film in the gas barrier laminate of the present invention has a wavelength of 1000 to 1120 cm in the infrared absorption spectrum of the coating film on the substrate. －１ It is preferable that the coating film of the gas barrier laminate of the present invention has an absorption peak in which the infrared absorption is maximum in the range of 1000 Hz to 1000 Hz. That is, as described above, the coating film of the gas barrier laminate of the present invention has excellent dispersibility of the metal oxide, and therefore a crosslinked structure based on the formation of the metal phosphate is efficiently formed. Therefore, the coating film has a maximum absorption peak in the above range derived from the metal phosphate.

[0021] As described above, the gas barrier laminate of the present invention has reduced hydroxyl groups derived from the metal oxide particle surfaces and phosphate compounds that are not used in the reaction in the coating film, and its uniform and dense structure allows it to suppress the permeation of non-polar gas molecules and polar gas molecules, resulting in excellent oxygen barrier properties and water vapor barrier properties, particularly excellent water vapor barrier properties. Gas molecules other than oxygen and water vapor that can be suppressed from permeating include, but are not limited to, hydrogen, helium, nitrogen, methane, ammonia, acidic gases such as hydrogen chloride, hydrogen sulfide, carbon dioxide, sulfur oxides, and nitrogen oxides. For example, a biaxially oriented polyethylene terephthalate film having a thickness of 25 μm can be used as a substrate, and a coating amount of 1.8 to 2.2 g / m2 can be applied to the substrate. ２ and a biaxially oriented polyethylene terephthalate film having a thickness of 25 μm formed thereon via an adhesive layer, the water vapor permeability of the gas barrier laminate being 0.100 g / m ２ ・It has excellent water vapor barrier properties, with a water vapor barrier strength of less than 1000 m / s (40°C, 90% RH) per day. In addition, the substrate is a biaxially oriented polyethylene terephthalate film with a thickness of 25 μm, and the coating amount on the substrate is 1.8 to 2.2 g / m. ２ and a biaxially oriented polyethylene terephthalate film having a thickness of 25 μm formed thereon via an adhesive layer. The oxygen permeability of the gas barrier laminate is 25 cc / m ２ It has excellent oxygen barrier properties, with a temperature of 40°C, 90% RH or less.

[0022] Furthermore, as described above, in the gas barrier laminate of the present invention, the metal oxide particles are uniformly and highly dispersed without aggregation, and a gas barrier coating film is formed as a uniform and smooth coating film having excellent optical properties. In addition, the haze is less than 9.0%, and the gas barrier laminate uses a biaxially oriented polyethylene terephthalate film having a thickness of 25 μm as a substrate, and the coating amount on the substrate is 1.8 to 2.2 g / m. ２ The gas barrier laminate having the coating film formed thereon has excellent optical properties, such as a total light transmittance of 80% or more and a gloss (glossiness) at an angle of 60° of 100 or more.

[0023] The gas barrier laminate of the present invention is a laminate comprising a substrate and a gas barrier layer comprising the gas barrier coating film described above formed on at least one surface thereof. Preferably, as shown in Figure 1, a gas barrier layer 3 is formed on substrate 1 via an anchor coat layer 2 described below. The anchor coat layer 2 is a coating film that has excellent adhesion to substrate 1, and by forming the gas barrier layer on this coating film, the interlayer adhesion between the gas barrier layer and the plastic substrate is significantly improved, preventing delamination in high-temperature or high-humidity environments and effectively preventing peeling of the gas barrier layer from the substrate even when subjected to retort sterilization, etc. Furthermore, in the gas barrier laminate of the present invention, it is preferable to form a resin layer 5 comprising a thermoplastic resin on the gas barrier layer 3 via an adhesive layer 4, as shown in Figure 2.

[0024] [Substrate] The substrate for the gas barrier laminate of the present invention may be a conventionally known substrate made of a resin such as a thermoplastic resin or a thermosetting resin, or a fiber such as paper or a nonwoven fabric, but preferred examples include films, sheets, and any packaging material or molded structure in the shape of a bottle, cup, tray, can, or the like, produced from a thermoformable thermoplastic resin by means of extrusion molding, biaxially oriented film molding, cast film molding, injection molding, blow molding, stretch blow molding, press molding, or the like.

[0025] Examples of thermoplastic resins constituting the substrate include olefin copolymers such as low-, medium-, or high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ionomer, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate, and polyethylene naphthalate; polyamides such as nylon 6, nylon 6,6, nylon 6,10, and metaxylylene adipamide; polyimides such as diamine-carboxylic anhydride copolymers; styrene copolymers such as polystyrene, styrene-butadiene block copolymer, styrene-acrylonitrile copolymer, and styrene-butadiene-acrylonitrile copolymer (ABS resin); vinyl chloride copolymers such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymer; acrylic copolymers such as polymethyl methacrylate and methyl methacrylate-ethyl acrylate copolymer; and polycarbonate. In addition, in view of recent environmental concerns, it is possible to use chemically recycled polyethylene terephthalate, mechanically recycled polyethylene terephthalate, biomass-derived polyethylene terephthalate, biomass-derived olefin, recycled olefin, etc. In the present invention, a sheet made of polyethylene terephthalate, polybutylene terephthalate, or polypropylene is particularly suitable.

[0026] These thermoplastic resins may be used alone or in the form of a blend of two or more types, or in the form of a laminate of different resins. The plastic substrate may have a single layer structure or a laminate structure of two or more layers, for example, formed by simultaneous melt extrusion or other lamination methods. Furthermore, the plastic material may be subjected to strength-enhancing processing such as uniaxial or biaxial stretching to improve heat resistance. If desired, one or more additives, such as pigments, antioxidants, antistatic agents, UV absorbers, and lubricants, may be added to the thermoformable thermoplastic resin in a total amount of 0.001 to 5.0 parts by weight per 100 parts by weight of the resin. For example, to reinforce the container, one or more types of fiber reinforcing materials such as glass fiber, aromatic polyamide fiber, carbon fiber, pulp, cotton linter, etc., powder reinforcing materials such as carbon black and white carbon, or flake-like reinforcing materials such as glass flakes and aluminum flakes can be blended in a total amount of 2 to 150 parts by mass per 100 parts by mass of the thermoplastic resin. Furthermore, for the purpose of increasing the amount, one or more types of heavy or soft calcium carbonate, mica, talc, kaolin, gypsum, clay, barium sulfate, alumina powder, silica powder, magnesium carbonate, etc. can be blended in a total amount of 5 to 100 parts by mass per 100 parts by mass of the thermoplastic resin according to a known recipe. Furthermore, for the purpose of improving gas barrier properties, scaly inorganic fine powders such as water-swellable mica, clay, etc. can be blended in a total amount of 5 to 100 parts by mass per 100 parts by mass of the thermoplastic resin according to a known recipe. Similarly, for the purpose of improving the gas barrier properties, there is no problem in providing a thin film layer of an inorganic material such as silicon oxide or aluminum oxide on a plastic substrate by physical or chemical vapor deposition.

[0027] The substrate may be a final film, sheet, or molded article such as a container, or the like, or the coating may be provided in advance on a preform for molding into a container. Examples of such preforms include cylindrical parisons with or without bottoms for biaxially stretched blow molding, pipes for molding plastic containers, sheets for vacuum forming, pressure forming, and plug-assist molding, or films for heat-sealed lids and bags.

[0028] [Anchor Coat Layer] As the anchor coat layer to be formed on the surface of the substrate as required, an anchor coat layer conventionally formed on a gas barrier laminate can be formed, and an anchor coat layer made of a conventionally known polyurethane resin formed by combining a hydroxyl group-containing compound as a main component such as an acrylic resin or polyol with an isocyanate-based curing agent, or an anchor coat layer further containing a silane coupling agent, or an anchor coat layer made of a hydrophilic group-containing resin and a silane coupling agent can be suitably used. The anchor coat layer-forming composition will be described later.

[0029] (Substrate for deposition) As described above, the gas barrier laminate of the present invention has excellent gas barrier properties, particularly excellent water vapor barrier properties, and therefore can be suitably used as a substrate on which a deposition film is formed. There are no particular limitations on the method for forming a deposition film on the substrate, and it can be formed by physical deposition such as sputtering, vacuum deposition, or ion plating, or chemical deposition such as plasma CVD. In addition, examples of the deposited film to be formed include, but are not limited to, gold, silver, copper, titanium, nickel, aluminum, silicon oxide, titanium oxide, aluminum oxide, a mixture of silica and alumina, indium tin oxide, diamond-like carbon, etc.

[0030] (Coating Composition for Forming Gas Barrier Coatings) The coating composition for forming a gas barrier coating film of the present invention, which is capable of forming a gas barrier coating film on a gas barrier laminate, is a coating composition for forming a gas barrier coating film containing a metal alkoxide, a hydrolysate of a metal alkoxide, at least one metal hydroxide, a metal oxide, and a phosphoric acid compound or a sulfate compound, and an important feature of this coating composition for forming a gas barrier coating film is that when the coating composition is dispersed in water / isopropanol (60 / 40) with a solids content of 5 to 7% by mass, the viscosity ratio (A / B) of the viscosity (A) at a spindle rotation speed of 50 rpm to the viscosity (B) at a spindle rotation speed of 200 rpm is less than 3.6, as measured at 25°C using a Brookfield viscometer. In other words, coating compositions generally have thixotropy, and this thixotropy depends on shear stress during dispersion treatment; therefore, if the rotation speed is high and high shear stress is applied, the viscosity will decrease, and if the rotation speed is low and the shear stress is weak, the viscosity will increase. The coating composition for forming a gas barrier coating film of the present invention has a low viscosity even at a low rotation speed (50 rpm) and a viscosity ratio (A / B) of less than 3.6, as described above, because the metal alkoxides, etc., metal oxides, and phosphate compounds, etc. in the coating composition are highly dispersed and have reduced thixotropy.

[0031]

[0023] The coating composition for forming a gas barrier coating film of the present invention, when dispersed in water / isopropanol (60 / 40) with a solids content of 5 to 7% by mass, preferably has a viscosity of less than 113.9 mPa·sec, particularly 26.2 to 96.0 mPa·sec, measured at 25°C using a Brookfield viscometer at a spindle rotation speed of 50 rpm. This allows the metal oxide particles and other particles in the coating composition for forming a gas barrier coating film to be uniformly dispersed without agglomeration, making it possible to form a coating film that exhibits excellent oxygen barrier properties and water vapor barrier properties. Furthermore, as described above, excellent coatability and leveling properties can be exhibited, making it possible to form a coating film without defects, and in this respect also excellent oxygen barrier properties and water vapor barrier properties can be exhibited.

[0032] As described above, the coating composition for forming a gas barrier coating film of the present invention contains at least one of a metal alkoxide, a metal alkoxide hydrolysate, and a metal hydroxide, together with a metal oxide and a phosphoric acid compound or a sulfate compound. This allows the metal oxide and the phosphoric acid compound to form a uniform and dense crosslinked structure, and the metal alkoxide and the phosphoric acid compound react with each other to become incorporated into the crosslinked structure, functioning as a binder between the metal oxide particles and thereby achieving excellent oxygen barrier properties and water vapor barrier properties. Furthermore, the reaction of the metal alkoxide and its hydrolysate, or the metal hydroxide with the phosphoric acid compound, does not cause yellowing, making it possible to form a colorless and transparent gas barrier coating film. Furthermore, this method is superior in terms of productivity, as it can be formed at a lower temperature and in a shorter time than conventional coating film formation methods that contain an amine compound and a carboxylic acid.

[0033] [Metal Oxide] The metal oxide used in the coating composition for forming a gas barrier coating film of the present invention is preferably an oxide of a divalent or higher metal atom, and is not limited thereto. Examples include oxides of magnesium, calcium, iron, zinc, aluminum, silicon, titanium, zirconium, etc., and zirconium oxide is particularly preferred. As used herein, the metal oxide contains a structure represented by M-O-M as the main component. M represents a metal atom, and O represents an oxygen atom. Zirconium oxide contains Zr and O as component elements, and amorphous zirconium oxide includes zirconium hydroxide (Zr(OH) ４ ) and / or zirconyl hydroxide (ZrO(OH) ２ ) as a main component, and the crystalline zirconium oxide contains hydrated zirconium oxide (ZrO ２ ・xH ２ O) and / or zirconium oxide (ZrO ２) as a main component. The term "main component" means a component contained in a proportion of 50% or more. The crystallinity of zirconium oxide and zirconium oxide formed into a gas barrier coating can be evaluated by identifying X-ray peaks specific to crystalline zirconium using a conventionally known X-ray structural diffractometer. In the present invention, either crystalline or amorphous zirconium oxide (zirconia) can be used as the zirconium oxide, but from the viewpoint of efficiently suppressing the permeation of gas molecules, crystalline zirconium oxide is particularly preferred.

[0034] In paints, zirconium oxide is used in the form of a sol containing zirconium oxide particles as a dispersoid and an inorganic acid such as nitric acid as a stabilizer, but in the present invention, in order to prevent the volatilization of the inorganic acid during coating film formation due to the inclusion of the inorganic acid, it is preferable to use a zirconium oxide sol that is substantially free of volatile acids, in which a carbonate, ammonium carbonate, organic dispersant, or the like is used instead of an inorganic acid such as nitric acid. Furthermore, since the binder component contains at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a metal hydroxide, which can provide many hydroxyl groups available for reaction with a phosphate compound, etc., the use of crystalline zirconium oxide, like the use of amorphous zirconium oxide, can provide both oxygen barrier properties and water vapor barrier properties equivalent to those of an amorphous zirconium oxide with many hydroxyl groups.

[0035] Furthermore, it is desirable that the zirconium oxide particles have an average primary particle size (D50) of 100 nm or less, preferably 50 nm or less, and more preferably 30 nm or less, thereby enabling the formation of a uniform coating film with excellent transparency. The average particle size (D50) is the volume-average particle size measured by a laser diffraction / scattering method, and D50 is the 50% value in the volume-based particle size distribution. By using such fine particle-type zirconium oxide as a raw material, excellent transparency can be achieved. Furthermore, the use of the above zirconium oxide particles enables the formation of a uniform and smooth coating film, and since zirconium oxide has a high refractive index, it can be used as a refractive index-adjusting layer.

[0036] [Phosphate Compound] Examples of the phosphoric acid compound used in the present invention include orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, cyclic polyphosphoric acid, phosphorous acid, phosphonic acid, and derivatives thereof. Specific examples of polyphosphoric acid include pyrophosphoric acid, triphosphoric acid, and polyphosphoric acid in which four or more phosphoric acids are condensed. Examples of the derivatives include salts, (partial) ester compounds, halides (chlorides, etc.), and dehydrates (diphosphorus pentoxide, etc.) of orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, phosphorous acid, and phosphonic acid. Furthermore, examples of derivatives of phosphonic acid include phosphonic acid (H-P(=O)(OH) ２ These phosphoric acid compounds include compounds in which the hydrogen atom directly bonded to the phosphorus atom of N,N,N',N'-ethylenediaminetetrakis(methylenephosphonic acid) is substituted with an alkyl group which may have various functional groups (e.g., nitrilotris(methylenephosphonic acid), N,N,N',N'-ethylenediaminetetrakis(methylenephosphonic acid) and the like), as well as salts, (partial) ester compounds, halides and dehydrates thereof. Furthermore, organic polymers containing phosphorus atoms, such as phosphorylated starch, can also be used. These phosphoric acid compounds can be used alone or in combination of two or more. In the present invention, it is particularly preferable to use at least one of orthophosphoric acid, metaphosphoric acid, polyphosphoric acid and cyclic polyphosphoric acid.

[0037] [Sulfuric acid compound] In the present invention, examples of the sulfate compound that can react with metal oxides to form a dense coating film instead of the above-mentioned phosphoric acid compound include compounds selected from the group consisting of sulfuric acid, sulfates, sulfate esters, alkyl sulfates, polyoxyethylene alkyl ether sulfates, and salts thereof. These sulfate compounds can be used alone or in combination of two or more. In the present invention, sulfuric acid is particularly suitable.

[0038] [Metal Alkoxide or Hydrolyzate Thereof] Metal alkoxides are generally represented by the following formula (1): M ｎ＋ (OR) ｎ－ In the formula (1), R represents an organic group having 1 to 8 carbon atoms, M represents a metal atom, and n represents an integer of 1 or more.

[0039] In the present invention, in the above formula (1), the metal atom M is preferably any one of aluminum, titanium, iron, and zirconium, and particularly preferably aluminum. Furthermore, in the above formula (1), the organic group R is preferably any one of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. In the present invention, as described above, the metal alkoxide is preferably at least one metal alkoxide selected from methoxide, ethoxide, propoxide, isopropoxide, butoxide, isobutoxide, sec-butoxide, and tert-butoxide, and among these, aluminum isopropoxide can be preferably used.

[0040] [Metal hydroxide] Metal hydroxide is generally represented by the following formula (2): M ｎ＋ (OH) ｎ－ ... (2) In the formula, H represents a hydrogen atom, M represents a metal atom, and n represents an integer of 1 or more. The metal hydroxide is preferably any of the hydroxides of aluminum, titanium, iron, and zirconium listed as examples of metal alkoxides, and among these, aluminum hydroxide is preferably used.

[0041] (Method for producing a coating composition for forming a gas barrier coating film) The coating composition for forming a gas barrier coating film of the present invention may be either an aqueous or solvent-based composition as long as it contains the above-mentioned metal oxide, phosphate compound, etc., and metal alkoxide, etc., but is preferably an aqueous composition. In the coating composition for forming a gas barrier coating film, it is desirable to use a sol containing metal oxide fine particles as the dispersoid as the metal oxide. Furthermore, as a sol containing metal oxide fine particles as the dispersoid, it is preferable to use a sol that does not contain a volatile acid as a stabilizer, in order to suppress the adverse effects of acid generation on equipment and the working environment. For the above reasons, it is desirable not to use volatile acids such as nitric acid, hydrochloric acid, acetic acid, trifluoroacetic acid, etc., which have been used to make dispersions with excellent transparency and viscosity stability, as peptizers.

[0042] The coating composition for forming a gas barrier coating film of the present invention is prepared by mixing the above-mentioned metal oxide, phosphate compound, etc., and metal alkoxide, etc. in a solvent capable of dissolving the phosphate compound, etc. and the metal alkoxide, etc. As such an aqueous medium, conventionally known aqueous solvents such as distilled water, ion-exchanged water, and pure water can be used, and, as with known aqueous compositions, organic solvents such as alcohols, polyhydric alcohols, their derivatives, and ketones can be contained. When such a co-solvent is used, it can be contained in an amount of 1 to 90 wt % relative to the aqueous solvent in the aqueous composition. By containing the solvent in the above range, film-forming performance is improved. Such organic solvents are preferably amphiphilic, and examples thereof include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, butyl cellosolve, propylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, 3-methyl-3-methoxybutanol, acetone, and methyl ethyl ketone.

[0043] In the method for producing a coating composition for forming a gas barrier coating film of the present invention, it is important that the metal oxide, phosphate compound, etc., are mixed in a solvent and then uniformly and highly dispersed without aggregation. Therefore, it is preferable to carry out a dispersion treatment. In the dispersion treatment, stirring is carried out so that the viscosity, measured at 25°C using a Brookfield viscometer with a spindle rotation speed of 50 rpm, is less than 113.9 mPa·sec, particularly in the range of 26.2 to 96.0 mPa·sec. Dispersion treatment methods can be used as long as they can adjust the viscosity to the above range, including, but not limited to, a conventional dispersion treatment that can pulverize fine particles by cavitation using an ultrasonic homogenizer, mechanical dispersion treatment using a disperser with rotating blades, and dispersion using a mill with glass or zirconia beads. Ultrasonic homogenizers are particularly suitable.

[0044] In the coating composition for forming a gas barrier coating film of the present invention, the phosphate compound, etc. and the metal alkoxide, etc. can be added to the metal oxide in an amount that does not impair the oxygen barrier property and water vapor barrier property. The amount of the phosphate compound, etc. to be added varies depending on the type of phosphate compound, etc. used and cannot be generally specified, but when zirconium oxide is used as the metal oxide, phosphoric acid as the phosphate compound, etc., and aluminum isopropoxide as the metal alkoxide, etc., it is preferable to blend in an amount of 53.5 to 90.9 parts by mass, and particularly 69.5 to 90.9 parts by mass, of the non-volatile content of the phosphoric acid per 100 parts by mass of the solid content of the zirconium oxide.

[0045] Furthermore, the amount of metal alkoxide etc. to be added varies depending on the type of metal alkoxide etc. used and cannot be generally defined, but when zirconium oxide is used as the metal oxide, phosphoric acid as the phosphate compound etc., and aluminum isopropoxide as the metal alkoxide etc., it is preferable to add aluminum isopropoxide in an amount of 44.7 to 76.0 parts by mass, particularly 58.1 to 76.0 parts by mass, per 100 parts by mass of the solids content of zirconium oxide. In the coating composition for forming a gas barrier coating film of the present invention, by ensuring that the contents of the phosphate compound and metal alkoxide etc. that serve as binder components are within the above ranges, it is possible to prepare a coating composition that can form a suitable coating film that has excellent transparency and gas barrier properties.

[0046] In the coating composition for forming a gas barrier coating film of the present invention, the binder components such as the phosphate compound and the metal alkoxide are preferably within the above-mentioned ranges, but even within the above-mentioned ranges, a higher content is particularly desirable because it reduces the viscosity of the coating composition. Therefore, in the coating composition for forming a gas barrier coating film of the present invention, by employing the above-mentioned high dispersion treatment or an increased amount of the binder component, or both, it is possible to suitably prepare a coating composition with the desired viscosity characteristics. Furthermore, by increasing the content of the phosphate compound and the metal alkoxide, the crosslinked structures formed in the coating film increase, and also the crosslinked structures of the metal phosphate, which is the reaction product of the metal alkoxide, etc., that serves as the binder between the metal compound particles, and the phosphate compound, also increase, making it possible to provide a coating composition that can form a defect-free coating film. Note that if the content of the phosphate compound and the metal alkoxide, etc., exceeds the above-mentioned ranges, not only will no further effect be obtained, but there is also a risk of defects in the barrier structure of the coating film compared to when it is within the above-mentioned ranges.

[0047] The coating composition for forming a gas barrier coating film of the present invention preferably contains a catalyst capable of promoting the reaction between the metal oxide or metal alkoxide used and the phosphate compound, etc. This promotes the crosslinking reaction of the coating composition, making it possible to reduce the heating temperature and heating time required for coating film formation. Examples of such catalysts include acid catalysts such as paratoluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, and cumenesulfonic acid, as well as amine neutralization products of these acids. Paratoluenesulfonic acid is particularly preferred. The acid catalyst is preferably contained in an amount of 0.1 to 10 parts by mass, particularly 1 to 3 parts by mass, per 100 parts by mass of the solids content of zirconium oxide. In addition to the above components, the coating composition for forming a gas barrier coating film may also contain crosslinkers, metal complexes, condensation accelerators, polymeric compounds, fillers, plasticizers, antioxidants, UV absorbers, flame retardants, antifoaming agents, colorants, etc.

[0048] (Method for producing a gas barrier laminate) In the method for producing a gas barrier laminate of the present invention, the coating composition for forming a gas barrier coating film of the present invention can be applied directly to at least one surface of the above-mentioned substrate, but it is preferable to apply the anchor coat layer-forming composition described below prior to applying the coating composition for forming a gas barrier coating film. The amount of the anchor coat layer-forming composition to be applied is determined by the contents of the polyurethane resin or carboxyl group-containing polyester resin and the silane coupling agent in the composition, and cannot be generally defined, but is generally 0.05 to 1.00 g / m2 in terms of the solids weight of the coating film. ２ , particularly 0.10 to 0.50 g / m ２It is preferable to apply the anchor coat layer so that the amount falls within the range. If the amount of anchor coat applied is less than the above range, the anchor coat layer may not be fixed to the substrate as well as when the amount is within the above range, while if the amount of anchor coat applied is more than the above range, it will be less economical. The anchor coat layer-forming composition applied to the substrate is dried at a temperature of 80 to 150°C for 1 to 60 seconds, depending on the composition and amount applied, to remove the solvent from the composition. This allows the anchor coat layer to be formed economically without affecting even when the substrate is made of a plastic with a low melting point, such as polypropylene.

[0049] Next, the coating composition for forming a gas barrier coating film is applied onto the composition for forming an anchor coat layer, which has been dried after the solvent has been removed. The amount of coating composition for forming a gas barrier coating film to be applied is determined by the contents of metal oxides, phosphate compounds, etc., and metal alkoxides, etc. in the composition, and cannot be generally defined, but is preferably 0.05 to 3.0 g / m2 in terms of the solids weight of the coating film. ２ , especially 0.1 to 2.5 g / m ２ It is preferable to coat the film so that the coating amount falls within the above range. If the coating amount is less than the above range, sufficient barrier properties cannot be obtained. On the other hand, if the coating amount is more than the above range, it is only economically inferior and does not offer any particular advantage.

[0050] In the coating composition for forming a gas barrier coating film of the present invention, a gas barrier layer can be formed by heating at a temperature of 80 to 220°C, preferably 140 to 220°C, for 1 second to 10 minutes, although this depends on the composition and application amount of the metal oxide, phosphate compound, etc., and metal alkoxide, etc., used in the composition. This reduces the difference in shrinkage due to heating between the gas barrier layer and the anchor coat layer, making it possible to improve the crack resistance of the gas barrier layer, and also significantly improves the interlayer adhesion between the gas barrier layer and the anchor coat layer, preventing peeling of the gas barrier layer from the substrate even when subjected to retort sterilization, etc. Furthermore, a coating film can be formed efficiently at a lower temperature and in a shorter time than conventional gas barrier layers.

[0051] The application, drying, or heat treatment of the anchor coat layer-forming composition and the gas barrier coating film-forming coating composition can be carried out by a conventionally known method. The application method is not limited to these, but can be, for example, spray coating, immersion, or application with a bar coater, roll coater, gravure coater, etc. Furthermore, the drying or heat treatment can be carried out by oven drying (heating), infrared heating, high-frequency heating, vacuum drying, superheated steam, etc.

[0052] [Anchor Coat Layer-Forming Composition] As the anchor coat layer-forming composition to be applied to the surface of the substrate as needed, as described above, an anchor coat layer-forming composition made of a conventionally known polyurethane resin obtained by combining a hydroxyl group-containing compound as a main component such as an acrylic resin or polyol with an isocyanate-based curing agent, or an anchor coat layer-forming composition further containing a silane coupling agent, or a hydrophilic group-containing resin and a silane coupling agent can be suitably used.

[0053] <Polyurethane Resin> The polyurethane resin constituting the anchor coat layer can be a polyurethane resin composed of a hydroxyl group-containing compound as a base component, such as a known acrylic resin or polyol, which has been conventionally used for anchor coat layers, and an isocyanate compound. In the present invention, it is desirable to use a polyurethane resin having a glass transition temperature (Tg) of 80°C or higher, particularly in the range of 80 to 120°C. If the glass transition temperature is lower than the above range, the heat resistance of the anchor coat layer will be inferior compared to when the glass transition temperature is within the above range. In addition, when the gas barrier layer is dried, cracks may occur in the gas barrier layer when the gas barrier coating film shrinks due to heating, resulting in a decrease in barrier properties.

[0054] Acrylic resins can be polymers and copolymers synthesized by solution polymerization or suspension polymerization using conventionally known radical initiators. The glass transition temperature of the acrylic resin is preferably -50 to 100°C, more preferably 40 to 100°C. The number-average molecular weight of the acrylic resin is preferably 500,000 to 100,000, more preferably 500,000 to 80,000. The hydroxyl value of the acrylic resin is preferably 10 to 200 mgKOH / g, more preferably 80 to 180 mgKOH / g. Monomers for copolymer formation are not particularly limited, but copolymers of methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-hydroxyethyl methacrylate, tert-butyl acrylate, and the like, combined as needed, can be used. Examples of polyols include glycols, polyester polyols, polyether polyols, acrylic polyols, and urethane-modified versions of these. Acrylic polyols and glycols are particularly preferred.

[0055] The glass transition temperature of the polyester polyol is preferably −50 to 100° C., more preferably −20 to 80° C. The number average molecular weight of these polyester polyols is preferably 500,000 to 100,000, more preferably 500,000 to 80,000. Examples of glycols include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, and 1,6-hexanediol.

[0056] The isocyanate component that serves as a curing agent for polyurethane resins may be an aromatic diisocyanate, an araliphatic diisocyanate, an alicyclic diisocyanate, an aliphatic diisocyanate, etc. Examples of aromatic diisocyanates include tolylene diisocyanate (2,4- or 2,6-tolylene diisocyanate or a mixture thereof) (TDI), phenylene diisocyanate (m-, p-phenylene diisocyanate or a mixture thereof), 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate (NDI), diphenylmethane diisocyanate (4,4'-, 2,4'-, or 2,2'-diphenylmethane diisocyanate or a mixture thereof) (MDI), 4,4'-toluidine diisocyanate (TODI), 4,4'-diphenyl ether diisocyanate, etc. Examples of the araliphatic diisocyanate include xylene diisocyanate (1,3- or 1,4-xylene diisocyanate or a mixture thereof) (XDI), tetramethyl xylene diisocyanate (1,3- or 1,4-tetramethyl xylene diisocyanate or a mixture thereof) (TMXDI), ω,ω'-diisocyanato-1,4-diethylbenzene, and the like.

[0057] Examples of alicyclic diisocyanates include 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), methylene bis(cyclohexyl isocyanate) (4,4'-, 2,4'-, or 2,2'-methylene bis(cyclohexyl isocyanate)) (hydrogenated MDI), methyl cyclohexane diisocyanate (methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate), bis(isocyanatomethyl)cyclohexane (1,3- or 1,4-bis(isocyanatomethyl)cyclohexane or a mixture thereof) (hydrogenated XDI), and the like.

[0058] Examples of aliphatic diisocyanates include trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate), hexamethylene diisocyanate, pentamethylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methyl caffeate.

[0059] The polyisocyanate component may be a polyfunctional polyisocyanate compound such as isocyanurate, biuret, or allophanate derived from the above polyisocyanate monomer, or a polyfunctional polyisocyanate compound containing a terminal isocyanate group obtained by reaction with a trifunctional or higher polyol compound such as trimethylolpropane or glycerin. The polyisocyanate component preferably has a glass transition temperature (Tg) of 50°C or higher and a number average molecular weight (Mn) of 400 or higher, and more preferably a glass transition temperature (Tg) of 60°C or higher and a number average molecular weight (Mn) of 500 or higher. In the present invention, of the above isocyanate components, it is preferable to use xylene diisocyanate.

[0060] <Hydrophilic Group-Containing Resin> Examples of hydrophilic group-containing resins include, but are not limited to, water-dispersible or water-soluble polyester resins, water-dispersible or water-soluble acrylic resins, and water-dispersible or water-soluble polyurethane resins. In the present invention, polyester resins are preferred, and among these, carboxyl group-containing polyester resins can be preferably used.

[0061] The carboxyl group-containing polyester resin can be prepared by combining a carboxylic acid anhydride such as phthalic anhydride, succinic anhydride, maleic anhydride, trimellitic anhydride, itaconic anhydride, or citraconic anhydride with a monomer component typically used in the polymerization of polyester resins. Examples of such monomer components include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and naphthalenedicarboxylic acid; aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and dimer acid; unsaturated dicarboxylic acids such as maleic acid (anhydride), fumaric acid, and terpene-maleic acid adducts; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydroisophthalic acid, and 1,2-cyclohexenedicarboxylic acid; and trivalent or higher polycarboxylic acids such as trimellitic acid (anhydride), pyromellitic acid (anhydride), and methylcyclohexene tricarboxylic acid. One or more of these may be selected and used. In the present invention, from the viewpoint of heat resistance, etc., it is preferable that the proportion of aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid in the polycarboxylic acid components constituting the polyester resin is 50 mol% or more.

[0062] The polyhydric alcohol component constituting the polyester resin is not particularly limited, and examples thereof include ethylene glycol, propylene glycol (1,2-propanediol), 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-2-butyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1-methyl-1,8-octanediol, 3-methyl-1,6-hexanediol, 4-methyl-1,7-heptanediol, 4-methyl The polyhydric alcohol component may be selected from aliphatic glycols such as 1,8-octanediol, 4-propyl-1,8-octanediol, and 1,9-nonanediol; ether glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; alicyclic polyalcohols such as 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, tricyclodecane glycols, and hydrated bisphenols; and trihydric or higher polyalcohols such as trimethylolpropane, trimethylolethane, and pentaerythritol. Among the above polyhydric alcohol components, ethylene glycol, propylene glycol, and neopentyl glycol can be preferably used in the present invention.

[0063] The carboxyl group-containing polyester resin can be produced by known methods, such as polycondensing one or more of the above-mentioned polycarboxylic acid components with one or more of the polyhydric alcohol components, depolymerizing the resulting mixture after polycondensation with a polycarboxylic acid component such as terephthalic acid, isophthalic acid, trimellitic anhydride, trimellitic acid, or pyromellitic acid, or ring-opening and adding an acid anhydride such as phthalic anhydride, maleic anhydride, trimellitic anhydride, or ethylene glycol bistrimellitate dianhydride after polycondensation.

[0064] The carboxyl group-containing polyester resin preferably has an acid value of 1 to 80 KOHmg / g, particularly 10 to 30 KOHmg / g, and a glass transition temperature (Tg) of 0 to 120°C, particularly 67 to 80°C. The carboxyl group-containing polyester resin used may be a blended polyester resin, as long as the acid value and Tg after blending are within the above ranges. The carboxyl group-containing polyester resin is preferably an amorphous polyester.

[0065] <Silane Coupling Agent> Epoxy-based silane coupling agents can be suitably used as the silane coupling agent used in the anchor coat layer. Examples of such epoxy-based silane coupling agents that can be used include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropyltrimethoxysilane. Other silane coupling agents include tetramethoxysilane, tetraethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and 3-isocyanatopropyltriethoxysilane, and can be used as needed. Furthermore, for the purpose of improving hot water-resistant adhesion, these silane coupling agents may be hydrolyzed as needed to promote a condensation reaction of the silane coupling agent.

[0066] The anchor coat layer-forming composition may be either water-based or solvent-based, but from the perspective of the working environment, an aqueous composition is preferred. When the anchor coat layer-forming composition uses the aforementioned polyurethane resin, it is preferable that it further contains an epoxy-based silane coupling agent. Furthermore, the polyurethane resin used is preferably a water-soluble or water-dispersible polyurethane. On the other hand, when the anchor coat layer-forming composition uses the aforementioned hydrophilic group-containing resin, it is preferable that it be prepared containing a carboxyl group-containing polyester resin and an epoxy-based silane coupling agent. The epoxy-based silane coupling agent is preferably contained in an amount of 1 to 80 parts by mass per 100 parts by mass of the solid content of the polyurethane resin, while it is preferably contained in an amount of 100 to 400 parts by mass, particularly 150 to 300 parts by mass per 100 parts by mass of the solid content of the carboxyl group-containing polyester resin. When the epoxy-based silane coupling agent is contained in an amount less than the above range, satisfactory crack resistance during drying cannot be obtained compared to when the amount is within the above range. On the other hand, even if the amount of epoxy-based silane coupling agent is greater than the above range, it is difficult to further improve adhesion and crack resistance, and there is a risk that hot water resistance may be impaired, and furthermore, it will be inferior from the viewpoint of economy.

[0067] The aqueous medium may contain the same conventionally known aqueous medium as that used in the composition for forming a gas barrier layer, as well as organic solvents such as alcohols, polyhydric alcohols, and derivatives thereof. In addition to the above components, the composition for forming an anchor coat layer may also contain known curing-accelerating catalysts, fillers, softeners, antioxidants, stabilizers, adhesion promoters, leveling agents, antifoaming agents, plasticizers, inorganic fillers, tackifying resins, fibers, colorants such as pigments, pot life extenders, and the like.

[0068] The present invention will be further explained by the following examples, but the present invention is not limited to these examples. Various measurement and evaluation methods in the examples and comparative examples are as follows.

[0069] Example 1 Preparation of a coating composition for forming a gas barrier coating film A coating composition for forming a gas barrier coating film (hereinafter referred to as a "barrier coat coating") was prepared by using a metal oxide, zirconium oxide sol (Zirconia sol ZSL-00120B (crystalline zirconium oxide, tetragonal system, solid content (ZrO ２ (converted to 0.01g / L, equivalent to 0.01g / L) = 20%) was used. First, a zirconium oxide sol was prepared using water and isopropanol solvent so that the solids content was 5 to 7% and the water / isopropanol ratio was 60 / 40. Next, 44.7 parts by mass of aluminum isopropoxide (manufactured by Wako Pure Chemical Industries, Ltd.) as an additive and 53.5 parts by mass of phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., concentration = 75%) as a phosphate compound were added to 100 parts by mass of the solids content of the zirconium oxide sol, and the mixture was dispersed using a homogenizer for a predetermined time to obtain a barrier coat paint.

[0070] [Method for Producing Gas Barrier Laminate] A gas barrier laminate was produced using the prepared barrier coating paint as follows: The above-mentioned barrier coating paint was applied to a substrate of a 25 μm-thick biaxially oriented polyester film (E5102, manufactured by Toyobo Co., Ltd.) using a bar coater in an amount of 1.8 to 2.2 g / m. ２ The mixture was then dried by heating in a box oven at 200° C. for 2 minutes to obtain a gas barrier laminate.

[0071] [Method of Preparing Samples for Evaluating Gas Barrier Properties, etc.] Samples for evaluating gas barrier properties, etc. (hereinafter referred to as "evaluation samples") were prepared by applying a coating amount of 4.0 g / m2 to the barrier coat surface of the gas barrier laminate. ２ A urethane adhesive (Takenate A-315 / Takenate A-50 manufactured by Mitsui Chemicals, Inc.) was applied to the substrate using a bar coater, dried using a dryer, and then laminated with the 25 μm thick biaxially oriented polyester film to prepare a sample for evaluation of gas barrier properties, etc.

[0072] Example 2 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 1, except that 47.0 parts by mass of aluminum isopropoxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added as an additive, and phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., concentration=75%) was added as a phosphate compound so that the non-volatile content of the phosphoric acid was 56.1 parts by mass relative to 100 parts by mass of the solid content of the zirconium oxide sol.

[0073] Example 3 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 1, except that 53.7 parts by mass of aluminum isopropoxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added as an additive, and phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., concentration=75%) was added as a phosphate compound so that the non-volatile content of the phosphoric acid was 64.2 parts by mass relative to 100 parts by mass of the solid content of the zirconium oxide sol.

[0074] Example 4 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 1, except that 58.1 parts by mass of aluminum isopropoxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added as an additive, and phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., concentration=75%) was added as a phosphate compound so that the non-volatile content of the phosphoric acid was 69.5 parts by mass relative to 100 parts by mass of the solid content of the zirconium oxide sol.

[0075] Example 5 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 1, except that 67.1 parts by mass of aluminum isopropoxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added as an additive, and phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., concentration=75%) was added as a phosphate compound so that the non-volatile content of the phosphoric acid was 80.2 parts by mass relative to 100 parts by mass of the solid content of the zirconium oxide sol.

[0076] Example 6 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 1, except that 71.5 parts by mass of aluminum isopropoxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added as an additive, and phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., concentration=75%) was added as a phosphate compound so that the non-volatile content of the phosphoric acid was 85.5 parts by mass relative to 100 parts by mass of the solid content of the zirconium oxide sol.

[0077] Example 7 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 1, except that 76.0 parts by mass of aluminum isopropoxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added as an additive, and phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., concentration=75%) was added as a phosphate compound so that the non-volatile content of the phosphoric acid was 90.9 parts by mass, relative to 100 parts by mass of the solid content of the zirconium oxide sol.

[0078] Example 8 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 1, except that 8.5 parts by mass of aluminum hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added as an additive, and phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., concentration=75%) was added as a phosphate compound so that the non-volatile content of the phosphoric acid was 53.5 parts by mass relative to 100 parts by mass of the solid content of the zirconium oxide sol.

[0079] Comparative Example 1 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 1, except that 40.3 parts by mass of aluminum isopropoxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added as an additive, and phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., concentration=75%) was added as a phosphate compound so that the non-volatile content of the phosphoric acid was 48.1 parts by mass relative to 100 parts by mass of the solid content of the zirconium oxide sol.

[0080] Comparative Example 2 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 1, except that the dispersion treatment using a rotary blade was carried out for a predetermined time.

[0081] Comparative Example 3 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 1, except that 80.5 parts by mass of aluminum isopropoxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added as an additive, and phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., concentration=75%) was added as a phosphate compound so that the non-volatile content of the phosphoric acid was 96.2 parts by mass relative to 100 parts by mass of the solid content of the zirconium oxide sol.

[0082] (Evaluation Method) Using the following evaluation methods, the evaluation results of the gas barrier laminate and the evaluation samples were obtained as shown in Tables 1 and 2.

[0083] [Oxygen Permeability] The oxygen permeability of each evaluation sample obtained in the examples and comparative examples was measured using an oxygen permeability measuring device (OX-TRAN2 / 21 manufactured by Modern Control Co., Ltd.) under the measurement conditions of a temperature of 40°C and a relative humidity of 90%.

[0084] [Water Vapor Permeability] The gas barrier property evaluation samples obtained in the Examples and Comparative Examples were measured using a water vapor permeability measuring device (PERMATRAN-W3 / 34 manufactured by Modern Control, Deltaperm-UH manufactured by Technolox, and HiBarSens 2.0 manufactured by Sempa) under the measurement conditions of a temperature of 40°C and a relative humidity of 90%.

[0085] [Infrared absorption spectrum] For each gas barrier laminate obtained in the Examples and Comparative Examples, the infrared absorption spectrum of the gas barrier coating film applied to the polyester substrate was measured using a Fourier transform infrared spectrophotometer (JASCO Corporation, FT / IR-6600). <Measurement conditions for FT-IR device> Instrument used: JASCO FT / IR-6600 Measurement conditions: Method: ATR (Ge prism) Detector: MCT Attachment: Thunder Dome Wavenumber range: 800 to 4000 cm －１ Film measurement surface Barrier coating surface

[0086] [Optical Properties] For each of the gas barrier laminates obtained in the Examples and Comparative Examples, the total light transmittance (%), haze (%) and gloss were measured using a haze meter (NDH8000 manufactured by Nippon Denshoku Industries Co., Ltd.) and a gloss meter (VG8000 manufactured by Nippon Denshoku Industries Co., Ltd.) with the polyester film substrate side as the detector side for measurement.

[0087] [X-ray fluorescence evaluation] As a method for evaluating the elements contained in each gas barrier laminate obtained in the examples and comparative examples, phosphorus, aluminum, and zirconium elements can be quantified using a commercially available X-ray fluorescence analyzer. The net strength obtained by measuring each gas barrier laminate was used to calculate the content ratio of each element in the coating film, by taking P / Zr for P and Zr and Al / Zr for Al and Zr, and used for evaluation. <Measurement conditions for X-ray fluorescence analyzer> Equipment used: ZSX Primus IV manufactured by Rigaku Corporation Measurement conditions: Measurement target: P-Kα ray, Al-Kα ray, Zr-Kα ray Measurement diameter: 10 mm Measurement X-ray: Rh (4.0 kW) Film measurement surface: Measurement was performed by irradiating X-rays from the barrier coating surface side.

[0088] [Viscosity] The viscosity of each barrier coat paint obtained in the examples and comparative examples was measured using a Brookfield DV2T type viscometer (manufactured by EKO Eiko Seiki Co., Ltd.) The measurement conditions were a temperature of 25°C, a spindle SC4-18, a chamber 13R, and rotation speeds of 50 rpm and 200 rpm.

[0089] The results of various measurements and evaluations of the above examples and comparative examples are shown in Tables 1 and 2.

[0090]

[0091]

[0092] [Abbreviations in Tables 1 and 2] NV: solid content of metal oxide in metal oxide sol, ZSL-00120B: crystalline zirconium oxide, TT: total light transmittance, Hz: haze, Gs (60°): gloss at an angle of 60°, P / Zr: content ratio of phosphorus element (P) derived from the phosphate compound to zirconium element (Zr) in the metal oxide in the gas barrier laminate, Al / Zr: content ratio of aluminum element (Al) derived from the additive to zirconium element (Zr) in the metal oxide in the gas barrier laminate.

[0093] The coating composition for forming a gas barrier coating film of the present invention is capable of forming a coating film having excellent oxygen barrier properties and water vapor barrier properties, and can be suitably used as a transparent high-barrier packaging material. Furthermore, since the gas barrier laminate has particularly excellent water vapor barrier properties, it can be used in applications such as, but not limited to, food packaging containers, packaging materials for retort pouches, pharmaceutical packaging materials, deposition substrates, electronic devices, circuit board materials, semiconductor materials, solar cell components, organic EL light-emitting element components, organic EL lighting components, electronic paper, and battery exteriors.

[0094] REFERENCE SIGNS LIST 1 substrate, 2 anchor coat layer, 3 gas barrier layer, 4 adhesive layer, 5 resin layer

Claims

1. A gas barrier laminate having a gas barrier coating film on a substrate, wherein the coating film comprises a reaction product obtained by reacting a metal alkoxide, a hydrolyzate of a metal alkoxide, at least one metal hydroxide, zirconium oxide, and a phosphate compound or a sulfate compound, and the content ratio (P / Zr) of Zr (Zr-Kα) and P (P-Kα) in an X-ray fluorescence measurement of the coating film is in the range of 1.39 to 2.59, and the infrared absorption spectrum of the coating film is in the range of 2600 to 3700 cm －１ The peak area (P2) and 850-1350 cm －１ a ratio (P2 / P1) of the peak areas (P1) of the above formula (I) to the peak areas (P2 / P1) of the above formula (I) is less than 0.

772.

2. A biaxially oriented polyethylene terephthalate film having a thickness of 25 μm is used as the substrate, and a coating amount of 1.8 to 2.2 g / m is applied to the substrate. ２ 2. The gas barrier laminate according to claim 1, wherein the gas barrier laminate having the coating film formed thereon has a haze of less than 9.0%.

3. The gas barrier laminate according to claim 1 or 2, wherein the metal species of the metal alkoxide, metal alkoxide hydrolysate, or metal hydroxide is aluminum, and the content ratio (Al / Zr) of Zr (Zr-Kα) and Al (Al-Kα) in the coating film measured by fluorescent X-rays is in the range of 0.15 to 0.

58.

4. The coating film has an infrared absorption spectrum of 1000 to 1120 cm －１ 3. The gas barrier laminate according to claim 1, wherein the infrared absorption has a maximum absorption peak in the range of 1000 to 10000.

5. A biaxially oriented polyethylene terephthalate film having a thickness of 25 μm is used as a substrate, and a coating amount formed on the substrate is 1.8 to 2.2 g / m ２ A gas barrier laminate obtained by laminating a biaxially oriented polyethylene terephthalate film having a thickness of 25 μm on the coating film via an adhesive layer has a water vapor permeability of 0.100 g / m ２ 3. The gas barrier laminate according to claim 1, wherein the gas barrier laminate has a temperature of less than 40° C. and 90% RH.

6. A deposition substrate comprising the gas barrier laminate according to claim 1 or 2.

7. A coating composition for forming a gas barrier coating film, which contains a metal alkoxide, a hydrolyzate of a metal alkoxide, at least one metal hydroxide, a metal oxide, and a phosphoric acid compound or a sulfate compound, wherein the coating composition for forming a gas barrier coating film, when dispersed in water / isopropanol (60 / 40) with a solids content of 5 to 7% by mass, has a viscosity ratio (A / B) of less than 3.6, measured at 25°C using a Brookfield viscometer, where the viscosity (A) is at a spindle rotation speed of 50 rpm and the viscosity (B) is at a spindle rotation speed of 200 rpm.

8. A coating composition for forming a gas barrier coating film according to claim 7, wherein the viscosity of the coating composition for forming a gas barrier coating film when dispersed in water / isopropanol (60 / 40) with a solids content of 5 to 7% by mass, measured at a temperature of 25°C using a Brookfield viscometer at a spindle rotation speed of 50 rpm, is less than 113.9 mPa·sec.

9. A coating composition for forming a gas barrier coating film according to claim 7 or 8, wherein the metal species of said metal alkoxide or metal hydroxide is at least one of aluminum, titanium, iron and zirconium.

10. A coating composition for forming a gas barrier coating film according to claim 7 or 8, wherein the metal alkoxide is at least one of methoxide, ethoxide, propoxide, isopropoxide, butoxide, isobutoxide, sec-butoxide and tert-butoxide.

11. A coating composition for forming a gas barrier coating film according to claim 7 or 8, wherein the metal alkoxide is aluminum isopropoxide.

12. A coating composition for forming a gas barrier coating film according to claim 7 or 8, wherein the metal hydroxide is aluminum hydroxide.

13. A coating composition for forming a gas barrier coating film according to claim 7 or 8, wherein the metal oxide is zirconium oxide or aluminum oxide.

14. A coating composition for forming a gas barrier coating film according to claim 7 or 8, wherein the metal oxide is crystalline zirconium oxide.

15. A coating composition for forming a gas barrier coating film according to claim 7 or 8, wherein the phosphoric acid compound is at least one of orthophosphoric acid, metaphosphoric acid, polyphosphoric acid and cyclic polyphosphoric acid.

16. A method for producing a coating composition for forming a gas barrier coating film according to claim 7, characterized in that a metal alkoxide, a hydrolysate of a metal alkoxide, at least one metal hydroxide, a metal oxide, and a phosphate compound or a sulfate compound are mixed together, and then stirred so that the viscosity at a spindle rotation speed of 50 rpm measured at a temperature of 25°C using a Brookfield viscometer is less than 113.9 mPa·sec.

Images