Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/02—Physical, chemical or physicochemical properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D1/00—Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances

Definitions

• 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. More specifically, the present invention relates 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 to a coating composition capable of forming such a coating film.
• Patent Document 1 describes a composite structure having a substrate (X) and a layer (Y) laminated on the substrate (X), wherein the layer (Y) contains a reaction product (R), and the reaction product (R) is a reaction product obtained by reacting at least a metal oxide (A) with a phosphorus compound (B), and the fraction (n 1 ) at which infrared absorption is maximized in the infrared absorption spectrum of the layer (Y) in the range of 800 to 1400 cm ⁇ 1 is in the range of 1080 to 1130 cm ⁇ 1 , and the metal atom (M) constituting the metal oxide (A) is aluminum.
• Patent Document 1 satisfies both the oxygen barrier property and the water vapor barrier property, but there are concerns about its stability against the acids and alkalis contained in the contents. Also, during the drying process of film formation, volatile acids contained in the paint are evaporated, which must be addressed, resulting in poor productivity.
• the present inventors have proposed a coating composition that uses a composite structure consisting of a reaction product of a metal oxide and a phosphate compound to solve the above problems, and that, by incorporating specific additives, can exhibit even better oxygen barrier properties and water vapor barrier properties (Patent Document 2).
• an amine compound containing polyvalent metal ions and an organic carboxylic acid is used as a specific additive.
• the polyvalent metal ions capture the metal ions, and the amine compound reacts with the metal ions, carboxylic acid, and phosphoric acid to become incorporated into a crosslinked structure and function as a binder between the metal oxide particles. This allows for the formation of a defect-free coating film, which can exhibit superior oxygen barrier properties and water vapor barrier properties.
• the present inventors have proposed a coating composition that 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.
• a coating film made from the above coating composition can be efficiently formed that not only has excellent oxygen barrier properties and water vapor barrier properties due to the uniform and dense crosslinked structure of the metal oxide and phosphate compound, but also has excellent transparency and is free from yellowing due to the reaction between the amine compound and carboxylic acid.
• the present inventors have found that the water vapor barrier properties of a coating film made from the above coating composition can be further improved. Accordingly, an object of the present invention is to provide a gas barrier laminate provided with a gas barrier coating film that has excellent oxygen barrier properties and transparency, as well as water vapor barrier properties that are even better than those of conventional gas barrier coating films, and a coating composition that can efficiently form such a gas barrier coating film.
• 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 hydrolysate of a metal alkoxide, at least one metal hydroxide, zirconium oxide, and a phosphate compound or a sulfate compound, and wherein, in fluorescent X-ray measurement of the coating film, the content ratio (P/Zr) of Zr (Zr-K ⁇ ) and P (P-K ⁇ ) is in the range of 1.39 to 2.59, and in an infrared absorption spectrum of the coating film, the ratio (P2/P1) of the peak area (P2) between 2600 and 3700 cm ⁇ 1 and the peak area (P1) between 850 and 1350 cm ⁇ 1 is less than 0.772.
• the coating film comprises a reaction product obtained by reacting a metal alkoxide, a hydrolysate of a metal alkoxide, at least one metal hydroxide, zirconium oxide, and
• a gas barrier laminate having a substrate of a biaxially oriented polyethylene terephthalate film having a thickness of 25 ⁇ m and having the coating film formed on the substrate in an amount of 1.8 to 2.2 g/ m2 has a haze of less than 9.0%;
• 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-K ⁇ ) and Al (Al-K ⁇ ) in the coating film measured by fluorescent X-rays is in the range of 0.15 to 0.58;
• the coating film has an infrared absorption peak in the range of 1000 to 1120 cm ⁇ 1 in an infrared absorption spectrum;
• the present invention further provides 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, and is characterized in that 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 of the coating composition when dispersed in water/isopropanol (60/40) with a solids content of 5 to 7% by mass is less than 3.6, as measured at 25°C using a Brookfield viscometer.
• 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
• the viscosity of the coating composition for forming a gas barrier coating film is less than 113.9 mPa sec;
• the metal species of the metal alkoxide or metal hydroxide is at least one of aluminum, titanium, iron, and zirconium;
• the metal alkoxide is at least one of methoxide, ethoxide, propoxide, isopropoxide, butoxide, isobutoxide, sec-butoxide, and tert-butoxide;
• the metal alkoxide is aluminum isopropoxide;
• the metal hydroxide is aluminum hydroxide.
• the metal oxide is zirconium oxide or aluminum oxide, [7] The metal oxide is a crystalline zirconium oxide. [8] The phosphoric acid compound is at least one of orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, and cyclic polyphosphoric acid; is preferred.
• the present invention also provides a method for producing the above-mentioned coating composition for forming a gas barrier coating film, which comprises mixing a metal alkoxide, a hydrolyzate of a metal alkoxide, at least one metal hydroxide, a metal oxide, and a phosphate compound or a sulfate compound, and then stirring the mixture so that the viscosity measured at a temperature of 25°C using a Brookfield viscometer with a spindle rotation speed of 50 rpm is less than 113.9 mPa ⁇ sec.
• the metal oxide is uniformly and highly dispersed without aggregation, which promotes the reaction between the metal oxide and the phosphate compound or sulfate compound, forming a uniform and dense crosslinked structure, thereby suppressing the permeation of nonpolar gas molecules and polar gas molecules and exhibiting excellent oxygen barrier property and water vapor barrier property. Furthermore, the amount of unreacted hydroxyl groups that serve as pathways for polar gases (water molecules) in the gas barrier coating film is reduced, further improving the water vapor barrier property.
• the transparency of the coating film is also excellent, and in the case of a laminate in which a coating film is formed on a 25 ⁇ m thick biaxially oriented polyethylene terephthalate substrate, the haze is less than 9.0%.
• 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 a gas barrier coating film, and the composition is capable of forming a uniform, smooth coating film with excellent coatability and leveling properties.
• FIG. 1 is a diagram showing a cross-sectional structure of an example of the gas barrier laminate of the present invention.
• FIG. 2 is a diagram showing the cross-sectional structure of another example of the gas barrier laminate of the present invention.
• Gas barrier laminate An important feature of the gas barrier coating film formed on the substrate in the gas barrier laminate of the present invention is that the ratio (P2/P1) of the peak area (P2) from 2600 to 3700 cm to the peak area (P1) from 850 to 1350 cm in the infrared absorption spectrum 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 hydrolyzate of a metal alkoxide, 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, and specifically, the 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.
• metal alkoxides, etc. also 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.
• 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, and in the case of a gas barrier laminate in which a coating film is formed in an amount of 1.8 to 2.2 g/ m2 on a biaxially stretched polyethylene terephthalate film with a thickness of 25 ⁇ m, the haze is less than 9.0%.
• 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 or the like, and aluminum isopropoxide or aluminum hydroxide as the metal alkoxide or the like, it is preferable that the content ratio (Al/Zr) of Zr (Zr-K ⁇ ) of zirconium oxide measured by X-ray fluorescence to Al (Al-K ⁇ ) of aluminum alkoxide or the like measured by X-ray fluorescence is in the range of 0.15 or more and less than 0.60, particularly in the range of 0.33 to 0.58, and further in the range of 0.43 to 0.58.
• 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 or the like, and aluminum isopropoxide or aluminum hydroxide as the metal alkoxide or the like, it is preferable that the content ratio (P/Zr) of Zr (Zr-K ⁇ ) of the zirconium oxide measured by X-ray fluorescence to P (P-K ⁇ ) of the phosphate compound measured by X-ray fluorescence measurement 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 further in the range of 1.91 to 2.59.
• 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. That is, if the content ratio determined by fluorescent X-ray measurement is less than the above range and there is an insufficient amount of phosphate compound, the metal oxide particles will not be bonded together sufficiently, and defects will occur in the structure of the coating film, which could result in reduced oxygen barrier properties and water vapor barrier properties.
• the coating film in the gas barrier laminate of the present invention preferably has an infrared absorption peak in the range of 1000 to 1120 cm in the infrared absorption spectrum of the coating film on the substrate. That is, as described above, the coating film in the gas barrier laminate of the present invention has excellent dispersibility of metal oxides, and therefore a crosslinked structure based on the formation of metal phosphate is efficiently formed. Therefore, the coating film has a maximum absorption peak in the above range derived from the metal phosphate.
• the gas barrier laminate of the present invention has a reduced number of hydroxyl groups derived from the phosphate compound and from the surfaces of metal oxide particles that are not used in the reaction in the coating film, and its uniform and dense structure makes it possible to inhibit the permeation of non-polar gas molecules and polar gas molecules, and therefore has excellent oxygen barrier properties and water vapor barrier properties, and is particularly excellent in water vapor barrier properties.
• gas molecules other than oxygen and water vapor that can be inhibited 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.
• a gas barrier laminate having a substrate of a 25 ⁇ m-thick biaxially oriented polyethylene terephthalate film, on which a coating film with a coating amount of 1.8 to 2.2 g/ m2 is applied, and further having a 25 ⁇ m-thick biaxially oriented polyethylene terephthalate film formed via an adhesive layer, has a water vapor permeability of less than 0.100 g/ m2 ⁇ day (40°C, 90% RH), and exhibits excellent water vapor barrier properties.
• a gas barrier laminate having a substrate of a 25 ⁇ m-thick biaxially oriented polyethylene terephthalate film, on which a coating film with a coating amount of 1.8 to 2.2 g/ m2 and a 25 ⁇ m-thick biaxially oriented polyethylene terephthalate film formed via an adhesive layer, has an oxygen permeability of 25 cc/m2 day atm or less (40°C, 90% RH), demonstrating excellent oxygen barrier properties.
• the substrate may also be a final film, sheet, or molded product such as a container, or this coating may be applied in advance to a preformed article to be molded into a container.
• preformed articles 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 bag making.
• the anchor coat layer formed on the surface of the substrate as needed can be an anchor coat layer that has been conventionally formed on gas barrier laminates, and can suitably be an anchor coat layer made of a conventionally known polyurethane resin that combines a hydroxyl group-containing compound as the main component, such as an acrylic resin or polyol, with an isocyanate 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.
• the anchor coat layer-forming composition will be described later.
• the coating composition for forming a gas barrier coating film which is capable of forming a gas barrier coating film on the gas barrier laminate of the present invention, 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, and an important feature of the coating composition for forming a gas barrier coating film is that when the coating composition is made into a water/isopropanol (60/40) dispersion having 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.
• paint compositions generally have thixotropy, and since this thixotropy depends on shear stress during dispersion treatment, the viscosity decreases when the rotation speed is high and high shear stress is applied, and increases when the rotation speed is low and shear stress is weak.
• the paint composition for forming gas barrier coatings of the present invention has low viscosity even at a low rotation speed (50 rpm), as described above, and is characterized by a viscosity ratio (A/B) of less than 3.6, because the metal alkoxides, metal oxides, phosphate compounds, etc. in the paint composition are highly dispersed and have reduced thixotropy.
• 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.
• excellent coatability and leveling properties can be achieved, making it possible to form a coating film without defects, which also contributes to the development of excellent oxygen barrier properties and water vapor barrier properties.
• the coating composition for forming a gas barrier coating film of the present invention contains at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a metal hydroxide, together with a metal oxide and a phosphoric acid compound or a sulfate compound, so that a uniform and dense crosslinked structure is formed by the metal oxide and the phosphoric acid compound, etc., and by reacting the metal alkoxide, etc. with the phosphoric acid compound, etc., it is incorporated into the crosslinked structure and functions as a binder between the metal oxide particles, thereby enabling the composition to exhibit excellent oxygen barrier properties and water vapor barrier properties.
• 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 includes, but is not limited to, oxides of magnesium, calcium, iron, zinc, aluminum, silicon, titanium, zirconium, etc., and zirconium oxide is particularly preferred.
• the metal oxide used in this specification contains a structure represented by MOM as a main component, where M represents a metal atom and O represents an oxygen atom.
• Zirconium oxide contains Zr and O as component elements
• amorphous zirconium oxide contains zirconium hydroxide (Zr(OH) 4 ) and/or zirconyl hydroxide (ZrO(OH) 2 ) as the main component
• crystalline zirconium oxide contains hydrated zirconium oxide ( ZrO2.xH2O ) and/or zirconium oxide ( ZrO2 ) as the main component.
• the term "main component” refers to a component contained in a proportion of 50% or more.
• the binder component contains at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a metal hydroxide, which are capable of providing many hydroxyl groups available for reaction with a phosphate compound or the like. Therefore, just as in the case of using amorphous zirconium oxide, even when crystalline zirconium oxide is used, it is possible to achieve both oxygen barrier properties and water vapor barrier properties equivalent to those achieved when amorphous zirconium oxide with many hydroxyl groups is used.
• organic polymers containing phosphorus atoms such as phosphorylated starch, can also be used. These phosphate 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.
• the metal atom M is preferably any one of aluminum, titanium, iron, and zirconium, and is particularly preferably aluminum.
• 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.
• 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.
• Metal hydroxides are 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.
• 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.
• a sol containing metal oxide fine particles as the dispersoid that does not contain a volatile acid as a stabilizer, in order to prevent the adverse effects of acid generation on equipment and the working environment.
• volatile acids such as nitric acid, hydrochloric acid, acetic acid, and trifluoroacetic acid, which have been used to prepare dispersions with excellent transparency and viscosity stability.
• 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.
• aqueous medium conventionally known aqueous solvents such as distilled water, ion-exchanged water, and pure water can be used.
• the composition can contain organic solvents such as alcohols, polyhydric alcohols, derivatives thereof, and ketones.
• organic solvents are those having amphiphilic properties, such as 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.
• the metal oxide, phosphate compound, etc. are uniformly and highly dispersed without aggregation after mixing in a solvent, and therefore it is preferable to carry out a dispersion treatment.
• stirring is carried out so that the viscosity measured at a temperature of 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.
• any conventionally known dispersion treatment can be used as long as it can adjust the viscosity to the above range.
• dispersion treatment examples include, but are not limited to, a method of crushing fine particles by cavitation using an ultrasonic homogenizer, a mechanical dispersion treatment using a disperser with rotating blades, and dispersion using a mill with glass or zirconia beads.
• an ultrasonic homogenizer can be preferably used.
• a phosphate compound and a metal alkoxide may be added to the metal oxide within a range that does not impair the oxygen barrier property and water vapor barrier property.
• the amount of the phosphate compound or the like to be added varies depending on the type of phosphate compound or the like used and cannot be generally specified.
• zirconium oxide is used as the metal oxide, phosphoric acid as the phosphate compound or the like, and aluminum isopropoxide as the metal alkoxide or the like, 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 nonvolatile content of phosphoric acid per 100 parts by mass of the solid content of zirconium oxide.
• the amount of metal alkoxide or the like to be added varies depending on the type of metal alkoxide or the like used and cannot be generally specified.
• zirconium oxide is used as the metal oxide
• phosphoric acid is used as the phosphate compound or the like
• aluminum isopropoxide is used as the metal alkoxide or the like
• the amount of the anchor coat layer-forming composition to be applied is determined by the content of the polyurethane resin or carboxyl group-containing polyester resin, and the silane coupling agent in the composition, and cannot be generally specified, but it is preferable to apply so that the solids weight of the coating film is in the range of 0.05 to 1.00 g/m 2 , particularly 0.10 to 0.50 g/m 2. If the anchor coat application amount is less than the above range, there is a risk that the anchor coat layer will not be able to be fixed to the substrate as compared with when it is within the above range, while if the anchor coat application amount is more than the above range, it will be less economical.
• a coating composition for forming a gas barrier coating film is applied onto the anchor coat layer-forming composition, 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 specified, but it is preferable to apply it so that the solids weight of the coating film is in the range of 0.05 to 3.0 g/m 2 , and particularly 0.1 to 2.5 g/m 2 . If the amount applied is less than the above range, sufficient barrier properties cannot be obtained. On the other hand, if the amount applied is greater than the above range, it will only be less economical and will not offer any particular advantage.
• 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, depending on the composition and application amount of the metal oxides, phosphate compounds, and metal alkoxides used in the composition. This reduces the difference in shrinkage due to heating between the gas barrier layer and the anchor coat layer, improving the crack resistance of the gas barrier layer and significantly improving 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.
• the application of the anchor coat layer forming composition and the gas barrier coating film forming coating composition, and the drying or heat treatment can be carried out by a conventionally known method.
• the application method is not limited to these, but for example, spray coating, immersion, or application with a bar coater, roll coater, gravure coater, or the like is possible.
• the drying or heating treatment can be carried out by oven drying (heating), infrared heating, high frequency heating, vacuum drying, superheated steam, or the like.
• an anchor coat layer-forming composition made of a conventionally known polyurethane resin that is a combination of a hydroxyl group-containing compound that serves as a main component, such as an acrylic resin or polyol, and an isocyanate-based curing agent, or an anchor coat layer-forming composition that further contains a silane coupling agent, or a hydrophilic group-containing resin and a silane coupling agent can be suitably used.
• a polyurethane resin composed of a hydroxyl group-containing compound as a main component such as a known acrylic resin or polyol, which has been conventionally used as an anchor coat layer, and an isocyanate compound can be used.
• Tg glass transition temperature
• the heat resistance of the anchor coat layer will be inferior compared to when the glass transition temperature is within the above range, and 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.
• the acrylic resin polymers and copolymers synthesized by solution polymerization or suspension polymerization using a conventionally known radical initiator or the like can be used.
• 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.
• the monomer for forming the copolymer is 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 necessary, can be used.
• polyols include glycols, polyester polyols, polyether polyols, acrylic polyols, and urethane-modified versions of these, with acrylic polyols and glycols being particularly preferred.
• 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.
• glycols include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, and 1,6-hexanediol.
• isocyanate component which is a curing agent for polyurethane resins
• aromatic diisocyanates aromatic diisocyanates, araliphatic diisocyanates, alicyclic diisocyanates, aliphatic diisocyanates, etc.
• aromatic diisocyanates aromatic diisocyanates, araliphatic diisocyanates, alicyclic diisocyanates, aliphatic diisocyanates, etc.
• 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), and 4,4'-diphenyl ether diisocyanate.
• TDI tolylene diisocyanate (2,4- or 2,6-tolylene diisocyanate or a mixture thereof)
• NDI 1,5-naphthalene diisocyanate
• MDI diphenylmethane diisocyanate
• 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), ⁇ , ⁇ '-diisocyanato-1,4-diethylbenzene, and the like.
• XDI xylene diisocyanate (1,3- or 1,4-xylene diisocyanate or a mixture thereof)
• TXDI tetramethyl xylene diisocyanate
• ⁇ , ⁇ '-diisocyanato-1,4-diethylbenzene and the like.
• alicyclic diisocyanates examples 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
• Aliphatic diisocyanates include, for example, 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.
• 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
• the polyisocyanate component may also be a polyfunctional polyisocyanate compound such as an isocyanurate, biuret, or allophanate derived from the above polyisocyanate monomer, or a polyfunctional polyisocyanate compound having 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 has a glass transition temperature (Tg) of 60° C. or higher and a number average molecular weight (Mn) of 500 or higher.
• Tg glass transition temperature
• Mn number average molecular weight
• Mn number average molecular weight
• 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.
• polyester resins are preferred, and carboxyl group-containing polyester resins are particularly preferred.
• 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.
• a carboxylic acid anhydride such as phthalic anhydride, succinic anhydride, maleic anhydride, trimellitic anhydride, itaconic anhydride, or citraconic anhydride
• 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
• 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.
• suitable polyhydric alcohols include 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.
• ethylene glycol, propylene glycol, and neopentyl glycol are preferred for use in the present invention.
• Carboxyl group-containing polyester resins can be produced by known methods, such as polycondensing one or more of the above 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 addition of an acid anhydride, such as phthalic anhydride, maleic anhydride, trimellitic anhydride, or ethylene glycol bistrimellitate dianhydride, after polycondensation.
• a polycarboxylic acid component such as terephthalic acid, isophthalic acid, trimellitic anhydride, trimellitic acid, or pyromellitic acid
• an acid anhydride such as phthalic anhydride, maleic anhydride, trimellitic anhydride, or ethylene glycol bistrimellitate dian
• 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, so 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.
• aluminum hydroxide manufactured by Wako Pure Chemical Industries, Ltd.
• aluminum isopropoxide manufactured by Wako Pure Chemical Industries, Ltd.
• 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 period of time.
• aluminum isopropoxide manufactured by Wako Pure Chemical Industries, Ltd.
• 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.
• the 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 converted into P/Zr for P and Zr, and into Al/Zr for Al and Zr, to calculate the content ratio of each element in the coating film, which was used for evaluation.
• the coating composition for forming a gas barrier coating film of the present invention is capable of forming a coating film that has excellent oxygen barrier properties and water vapor barrier properties, and can be suitably used as a transparent high-barrier packaging material.
• the gas barrier laminate has particularly excellent water vapor barrier properties, its uses include, but are 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.

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