JP7606864B2 - Gas barrier laminate - Google Patents

Description

The present invention relates to a gas barrier laminate.

Patent Document 1 (WO 2011/122036) describes a technology for improving the retort resistance of gas barrier materials. The document describes a composite structure having a substrate and a layer laminated on the substrate, the layer including a reaction product and a polymer, the reaction product being a reaction product of at least a metal oxide and a phosphorus compound, and the layer having specific properties in terms of the infrared absorption spectrum. It also describes that the polymer is preferably at least one polymer selected from the group consisting of polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polysaccharide, polyacrylic acid, a salt of polyacrylic acid, polymethacrylic acid, and a salt of polymethacrylic acid.

International Publication No. 2011/122036

The technical level required for various properties of gas barrier materials is becoming increasingly higher. Therefore, the inventors have examined the technologies described in the above patent documents and found that even when these technologies are used, there is still room for improvement in gas barrier materials in terms of improving productivity and barrier properties in a balanced manner. Although there have been many technologies that have focused on improving barrier performance, no technology has been reported that improves barrier properties and productivity in a balanced manner.

The present invention was made in consideration of the above circumstances, and provides a gas barrier material that has an excellent balance between productivity and barrier properties and exhibits favorable barrier properties in a variety of layer structures.

According to the present invention, the following gas barrier laminate is provided:

[1] A base material layer,
a gas barrier layer provided on at least one surface of the base layer;
an inorganic layer provided between the base layer and the gas barrier layer;
Including,
The gas barrier layer is formed of a cured mixture containing a polycarboxylic acid, a polyamine compound, a polyvalent metal compound, and a phosphorus compound containing one or more -P-OH groups or a salt thereof.
[2] The gas barrier laminate according to [1], further comprising an undercoat layer provided between the base layer and the inorganic layer.
[3] The gas barrier laminate according to [1] or [2], wherein the inorganic layer is a vapor-deposited film provided on the base layer, or on an intervening layer when an intervening layer is present between the base layer and the inorganic layer, and is composed of one or more inorganic substances selected from the group consisting of silicon oxide, aluminum oxide, and aluminum.
[4] In the infrared absorption spectrum of the gas barrier layer,
The maximum peak height of absorbance in the range of 1300 ^cm to 1490 ^cm is defined as α,
When the maximum peak height of absorbance in the range of 1690 ^cm to 1780 ^cm is γ,
The gas barrier laminate according to any one of [1] to [3], wherein the ratio of free carboxy groups to NH ₃ complexes represented by γ/α is 0.00 or more and 1.00 or less.
[5] In the infrared absorption spectrum of the gas barrier layer,
The total peak area in the absorption band range of 1493 cm ⁻¹ to 1780 cm ⁻¹ is defined as A,
The total peak area in the absorption band range of 1598 cm ⁻¹ to 1690 cm ⁻¹ is defined as B,
The total peak area in the absorption band range of 1690 cm ⁻¹ to 1780 cm ⁻¹ is defined as C,
When the total peak area in the absorption band range of 1493 cm ⁻¹ to 1598 cm ⁻¹ is D,
the area ratio of amide bonds represented by B/A is 0.200 or more and 0.370 or less,
the area ratio of carboxylic acid represented by C/A is 0.150 or less;
The gas barrier laminate according to any one of [1] to [4], wherein the area ratio of the carboxylate represented by D/A is 0.580 or more and 0.800 or less.
[6] The gas barrier laminate according to any one of [1] to [5], wherein the gas barrier layer has a thickness of 0.01 μm or more and 15 μm or less.
[7] The gas barrier laminate according to any one of [1] to [6], wherein the polyvalent metal compound is a compound of one or more divalent or higher metals selected from the group consisting of Zn, Ca, Mg, Ba and Al.
[8] The gas barrier laminate according to any one of [1] to [7], wherein (the number of moles of P atoms derived from the phosphorus compound or the salt thereof in the mixture)/(the number of moles of -COO- groups derived from the polycarboxylic acid in the mixture) is 0.001 or more and 0.3 or less.
[9] The gas barrier laminate according to any one of [1] to [8], wherein the phosphorus compound is one or more selected from the group consisting of phosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, phosphonic acid, and salts thereof.
[10] The gas barrier laminate according to any one of [1] to [9], wherein (the number of moles of the polyvalent metal derived from the polyvalent metal compound in the mixture)/(the number of moles of -COO- groups derived from the polycarboxylic acid in the mixture) is 0.10 or more and 0.80 or less.
[11] The gas barrier laminate according to any one of [1] to [10], wherein (the number of moles of polyvalent metal derived from the polyvalent metal compound in the mixture)/(the number of moles of amino groups derived from the polyamine compound in the mixture) is 0.25 or more and 0.65 or less.
[12] The gas barrier laminate according to any one of [1] to [11], wherein the polycarboxylic acid includes one or more polymers selected from the group consisting of polyacrylic acid, polymethacrylic acid, and a copolymer of acrylic acid and methacrylic acid.
[13] The gas barrier laminate according to any one of [1] to [12], wherein the polyamine compound contains polyethyleneimine.
[14] The gas barrier laminate according to any one of [1] to [13], wherein the base layer contains one or more resins selected from the group consisting of polyamide, polyethylene terephthalate, and polybutylene terephthalate.

The present invention provides a gas barrier material that has an excellent balance between productivity and barrier properties and exhibits favorable barrier properties in a variety of layer structures.

FIG. 1 is a cross-sectional view that illustrates an example of the structure of a gas barrier laminate according to an embodiment. FIG. 1 is a cross-sectional view that illustrates an example of the structure of a gas barrier laminate according to an embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are schematic diagrams and do not correspond to the actual dimensional ratio.
In this specification, unless otherwise specified, the symbol "~" between numbers in a sentence indicates a range from above to below, and includes both ends of the value.
In this specification, (meth)acrylic acid refers to at least one of acrylic acid and methacrylic acid, and (meth)acrylate refers to at least one of acrylate and methacrylate.
In this embodiment, the composition may contain each component alone or in combination of two or more types.

(Gas Barrier Laminate)
Fig. 1 is a cross-sectional view showing a schematic example of the configuration of a gas barrier laminate in an embodiment. The gas barrier laminate 100 shown in Fig. 1 includes a base layer 101, a gas barrier layer 103 provided on at least one surface of the base layer 101, and an inorganic layer 102 provided between the base layer 101 and the gas barrier layer 103. The gas barrier layer 103 is formed of a cured product of a mixture including a polycarboxylic acid, a polyamine compound, a polyvalent metal compound, and a phosphorus compound or a salt thereof having one or more -P-OH groups.
The specific structure of each layer will be described later.

In the gas barrier laminate 100, a base layer 101, an inorganic layer 102 and a gas barrier layer 103 are laminated in this order, and the gas barrier layer 103 is composed of a cured product of the above-mentioned mixture. As a result, the gas barrier laminate 100 has an excellent balance between barrier properties and productivity, and exhibits favorable barrier properties in a variety of layer structures.
More specifically, the gas barrier laminate 100 has excellent barrier properties such as oxygen barrier property and water vapor barrier property after retort treatment. In the gas barrier laminate 100, the gas barrier layer 103 is formed of the cured product of the above-mentioned mixture, so that the gas barrier laminate 100 having excellent barrier properties can be obtained even if the curing time for obtaining the gas barrier layer 103, specifically the heat treatment time, is short.
In addition, since the gas barrier layer 103 is composed of a cured product of a mixture containing a polycarboxylic acid, a polyamine compound, a polyvalent metal compound, and a phosphorus compound or a salt thereof containing one or more -P-OH groups, it is possible to obtain a gas barrier laminate 100 having excellent barrier properties and water resistance, for example.

Fig. 2 is a cross-sectional view showing a schematic configuration of another example of a gas barrier laminate. The basic configuration of a gas barrier laminate 110 shown in Fig. 2 is similar to that of the gas barrier laminate 100 described above with reference to Fig. 1, but differs in that it further includes an undercoat layer 104 provided between a base layer 101 and an inorganic layer 102.
The gas barrier laminate 110 also provides the same effects as the gas barrier laminate 100. In addition, in the gas barrier laminate 110, by providing an undercoat layer 104 between the base layer 101 and the inorganic layer 102, the adhesion between the base layer 101 and the inorganic layer 102 can be further improved.
The configuration of the layers included in the gas barrier laminate will now be described in more detail. First, the gas barrier layer 103 will be described.

(Gas Barrier Layer)
The gas barrier layer 103 is made of a cured product of a mixture containing a polycarboxylic acid, a polyamine compound, and a polyvalent metal compound. More specifically, the gas barrier layer 103 is a film (gas barrier film 10) made of the cured product.
More specifically, the gas barrier layer 103 is obtained by applying a pre-cured mixture, i.e., a gas barrier coating material, to a layer disposed directly below the gas barrier layer 103, such as the inorganic layer 102, followed by drying and heat treatment to harden the gas barrier coating material.

In the infrared absorption spectrum of the gas barrier layer 103, when the maximum peak height of absorbance in the range of 1300 cm ^-1 to 1490 cm ^-1 is defined as α and the maximum peak height of absorbance in the range of 1690 cm ^-1 to 1780 cm ^-1 is defined as γ, the ratio of free carboxy groups to _NH3 complexes, expressed as γ/α, is preferably 0.00 or more, more preferably 0.01 or more, and even more preferably 0.02 or more, from the viewpoint of the liquid stability of the gas barrier coating material before coating.
Furthermore, from the viewpoint of improving the barrier properties of the gas barrier layer 103 obtained after coating, the above γ/α is preferably 1.00 or less, more preferably 0.80 or less, even more preferably 0.60 or less, still more preferably 0.40 or less, even more preferably 0.20 or less, and still more preferably 0.10 or less.

In addition, in the infrared absorption spectrum of the gas barrier layer 103, when the total peak area in the absorption band range of 1493 cm ^-1 or more and 1780 cm- ¹ or less is defined as A, the total peak area in the absorption band range of 1598 cm ^-1 or more and 1690 cm ^-1 or less is defined as B, the total peak area in the absorption band range of 1690 cm ^-1 or more and 1780 cm ^-1 or less is defined as C, and the total peak area in the absorption band range of 1493 cm ^-1 or more and 1598 cm ^-1 or less is defined as D, preferred examples of the area ratios are shown below.
In the infrared absorption spectrum of the gas barrier layer 103, the area ratio of amide bonds represented by B/A is preferably 0.200 or more, more preferably 0.220 or more, and even more preferably 0.250 or more, from the viewpoint of further improving the gas barrier performance after retort treatment.
From the viewpoint of further improving the balance between the barrier property and productivity, the area ratio of the amide bonds represented by the above B/A is preferably 0.370 or less, more preferably 0.350 or less, and even more preferably 0.300 or less.

In the infrared absorption spectrum of the gas barrier layer 103, the area ratio of carboxylic acid represented by C/A is preferably 0.150 or less, more preferably 0.100 or less, even more preferably 0.080 or less, and still more preferably 0.060 or less, from the viewpoint of further improving the gas barrier performance after retort treatment.
The lower limit of the area ratio of carboxylic acid represented by C/A is not limited, but may be, for example, 0.000 or more, and may be, for example, 0.0001 or more.

In the infrared absorption spectrum of the gas barrier layer 103, the area ratio of the carboxylate represented by D/A is preferably 0.580 or more, and more preferably 0.600 or more, from the viewpoint of further improving the balance between the barrier property and the productivity.
From the viewpoint of further improving the gas barrier performance after retort treatment, the above D/A is preferably 0.800 or less, more preferably 0.780 or less, even more preferably 0.760 or less, and still more preferably 0.740 or less.

Furthermore, from the viewpoint of achieving a more favorable balance between the productivity and barrier properties of the gas barrier laminate, it is also preferable that the area ratio of amide bonds represented by B/A is 0.200 or more and 0.370 or less, the area ratio of carboxylic acids represented by C/A is 0.150 or less, and the area ratio of carboxylates represented by D/A is 0.580 or more and 0.800 or less.

In the infrared absorption spectrum of the gas barrier layer 103, the area ratio of the carboxylate represented by D/A to the area ratio of the amide bond represented by B/A is preferably 1.2 or more, more preferably 1.5 or more, and more preferably 2.0 or more, from the viewpoint of improving the barrier property.
In addition, from the viewpoint of improving the barrier property after retort, the area ratio of the carboxylate represented by D/A to the area ratio of the amide bond represented by B/A is preferably 4.0 or less, more preferably 3.5 or less, and even more preferably 3.0 or less.

Here, in the infrared absorption spectrum of the gas barrier layer 103, absorption due to the νC=O of unreacted carboxylic acid is observed at around 1700 cm ^-1 , absorption due to the νC=O of the amide bond which is a cross-linked structure is observed at around 1630 to 1685 cm ^-1 , absorption due to the νC=O of the carboxylate is observed at around 1540 to 1560 cm ^-1 , and absorption due to the δN-H of ammonia which forms a complex is observed at around 1300 to 1490 cm ^-1 .

The maximum peak height α of the absorbance in the range of 1300 cm ⁻¹ to 1490 cm ⁻¹ in the infrared absorption spectrum is considered to represent an index of the amount of ammonia present that forms a complex, and the maximum peak height γ in the range of 1690 cm ⁻¹ to 1780 cm ⁻¹ is considered to represent an index of the amount of free, i.e., unreacted, carboxylic acid present.

In this embodiment, the maximum peak heights α and γ can be measured specifically by the following procedure. That is, a measurement sample of 1 cm×3 cm is cut out from the gas barrier layer 103. Next, an infrared absorption spectrum of the surface of the gas barrier layer 103 is obtained by infrared total reflection measurement (ATR method). In the obtained infrared absorption spectrum, a straight line connecting the absorbance at 900 cm ⁻¹ and the absorbance at 1900 cm ⁻¹ is set as a baseline, and the maximum peak height in each absorbance range is determined.

In addition, the total peak area A in the absorption band range of 1493 cm ^-1 to 1780 cm ^-1 in the infrared absorption spectrum is considered to represent an index of the total amount of carboxylic acid, amide bond, and carboxylate, and the total peak area B in the absorption band range of 1598 cm ^{-1 to} 1690 cm-1 is considered to represent an index of the amount of amide bond present. Furthermore, the total peak area C in the absorption band range of 1690 cm ^-1 to 1780 cm ^-1 is considered to represent an index of the amount of unreacted carboxylic acid present, and the total peak area D in the absorption band range of 1493 cm ^-1 to 1598 cm ^-1 is considered to represent an index of the amount of carboxylate present.

In this embodiment, the total peak areas A to D can be specifically measured by the following procedure.
First, a measurement sample of 1 cm x 3 cm is cut out from the gas barrier layer 103. Next, the infrared absorption spectrum of the surface of the gas barrier layer 103 is obtained by infrared total reflection measurement (ATR method). From the obtained infrared absorption spectrum, the above total peak areas A to D are calculated by the following steps (1) to (4).
(1) The absorbances at 1780 cm ^-1 and 1493 cm ^-1 are connected by a straight line (N), and the area enclosed by the absorption spectrum in the absorption band range from 1493 cm ^-1 to 1780 cm ^-1 and N is defined as the total peak area A.
(2) Draw a line (O) vertically from the absorbance (Q) at 1690 cm ^-1 , and let P be the intersection point of N and O. Draw a line (S) vertically from the absorbance (R) at 1598 cm ^-1 , and let T be the intersection point of N and S. The total peak area B is the area enclosed by the absorption spectrum in the absorption band range from 1598 cm ^-1 to 1690 cm ^-1 , line S, point T, line N, point P, line O, absorbance Q, and absorbance R.
(3) The absorption spectrum in the absorption band range of 1690 cm ⁻¹ to 1780 cm ⁻¹ , the area surrounded by the absorbance Q, the line O, the point P, and the line N is defined as a total peak area C.
(4) The absorption spectrum in the absorption band range of 1493 cm ⁻¹ to 1598 cm ⁻¹ , the area surrounded by the absorbance R, the line S, the point T, and the line N is defined as a total peak area D.
Next, the area ratios B/A, C/A, and D/A are calculated from the areas calculated by the above method.

In this embodiment, the infrared absorption spectrum can be measured (infrared total reflection measurement: ATR method) using, for example, an IRT-5200 device manufactured by JASCO Corporation, equipped with a PKM-GE-S (Germanium) crystal, under the conditions of an incident angle of 45 degrees, room temperature, a resolution of 4 cm ^-1 , and an accumulation count of 100.

The maximum peak heights α and γ of the gas barrier layer 103, as well as the area ratio of the amide bond represented by B/A, the area ratio of the carboxylic acid represented by C/A, and the area ratio of the carboxylate represented by D/A, can be controlled by appropriately adjusting the manufacturing conditions of the gas barrier layer 103. Specifically, the blending ratio of the polycarboxylic acid, polyamine compound, polyvalent metal compound, and phosphorus compound, the preparation method of the mixture before curing, and the method, temperature, and time of the heat treatment of the mixture are cited as factors for controlling the maximum peak heights α and γ of the gas barrier layer 103, as well as the area ratio of the amide bond represented by B/A, the area ratio of the carboxylic acid represented by C/A, and the area ratio of the carboxylate represented by D/A.

Next, the components contained in the mixture (gas barrier coating material) before curing will be described.
(Polycarboxylic acid)
The polycarboxylic acid has two or more carboxy groups in the molecule. Specific examples include homopolymers of α,β-unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, fumaric acid, crotonic acid, cinnamic acid, 3-hexenoic acid, and 3-hexenedioic acid, and copolymers thereof. In addition, copolymers of the above α,β-unsaturated carboxylic acids with esters such as ethyl esters, and olefins such as ethylene, and the like may also be used.

Among these, homopolymers of acrylic acid, methacrylic acid, itaconic acid, fumaric acid, crotonic acid, and cinnamic acid or copolymers thereof are preferred, and one or more polymers selected from the group consisting of polyacrylic acid, polymethacrylic acid, and copolymers of acrylic acid and methacrylic acid are more preferred, and at least one polymer selected from polyacrylic acid and polymethacrylic acid is even more preferred, and at least one polymer selected from homopolymers of acrylic acid and homopolymers of methacrylic acid are even more preferred.

In the present embodiment, the polyacrylic acid includes both a homopolymer of acrylic acid and a copolymer of acrylic acid and another monomer. In the case of a copolymer of acrylic acid and another monomer, the polyacrylic acid contains acrylic acid-derived structural units in 100% by mass of the polymer in an amount of usually 90% by mass or more, preferably 95% by mass or more, and more preferably 99% by mass or more.
In the present embodiment, the polymethacrylic acid includes both a homopolymer of methacrylic acid and a copolymer of methacrylic acid and another monomer. In the case of a copolymer of methacrylic acid and another monomer, the polymethacrylic acid contains methacrylic acid-derived structural units in 100% by mass of the polymer in an amount of usually 90% by mass or more, preferably 95% by mass or more, and more preferably 99% by mass or more.

The polycarboxylic acid is a polymer obtained by polymerizing a carboxylic acid monomer. From the viewpoint of achieving an excellent balance between gas barrier properties and handleability, the molecular weight of the polycarboxylic acid is preferably 500 to 2,500,000, more preferably 5,000 to 2,000,000, more preferably 10,000 to 1,500,000, and even more preferably 100,000 to 1,200,000.
In this embodiment, the molecular weight of the polycarboxylic acid is a weight average molecular weight calculated as polyethylene oxide, and can be measured by gel permeation chromatography (GPC).

The polycarboxylic acid may be at least partially neutralized with a volatile base. By neutralizing the polycarboxylic acid with a volatile base, gelation can be suppressed when the polycarboxylic acid is mixed with a polyvalent metal compound or a polyamine compound. Therefore, in the polycarboxylic acid, it is preferable to partially or completely neutralize the carboxyl group with a volatile base from the viewpoint of preventing gelation. The neutralized product can be obtained by partially or completely neutralizing the carboxyl group of the polycarboxylic acid with a volatile base, that is, by partially or completely converting the carboxyl group of the polycarboxylic acid into a carboxylate. This can prevent gelation when the polyamine compound or the polyvalent metal compound is added.
The partially neutralized product can be prepared by adding a volatile base to an aqueous solution of a polycarboxylic acid polymer, and the desired degree of neutralization can be achieved by adjusting the ratio of the amount of polycarboxylic acid to the volatile base. In this embodiment, the degree of neutralization of the polycarboxylic acid by the volatile base is preferably 70 to 300 equivalent %, more preferably 90 to 250 equivalent %, and even more preferably 100 to 200 equivalent %, from the viewpoint of sufficiently suppressing gelation caused by the neutralization reaction with the amino group of the polyamine compound.

As the volatile base, any water-soluble base can be used.
Examples of the volatile base include ammonia, morpholine, alkylamines, tertiary amines such as 2-dimethylaminoethanol, N-methylmorpholine, ethylenediamine, and triethylamine, and aqueous solutions thereof, or mixtures thereof. From the viewpoint of obtaining good gas barrier properties, an aqueous ammonia solution is preferred.

(Polyamine Compound)
The mixture before curing contains a polyamine compound. By containing a polyamine compound, the barrier properties of the resulting gas barrier material can be improved.
The polyamine compound is a compound having two or more amino groups in the main chain, side chain, or end, and is preferably a polymer.Specific examples include aliphatic polyamines such as polyallylamine, polyvinylamine, polyethyleneimine, and poly(trimethyleneimine); polyamides having amino groups in the side chain such as polylysine and polyarginine; and the like.In addition, polyamines in which some of the amino groups are modified may also be used.
From the viewpoint of obtaining good gas barrier properties, the polyamine compound preferably contains polyethyleneimine, and more preferably is polyethyleneimine.

From the viewpoint of achieving an excellent balance between gas barrier properties and handleability, the number average molecular weight of the polyamine compound is preferably 50 to 2,000,000, more preferably 100 to 1,000,000, even more preferably 1,500 to 500,000, even more preferably 1,500 to 100,000, even more preferably 1,500 to 50,000, even more preferably 3,500 to 20,000, even more preferably 5,000 to 15,000, and even more preferably 7,000 to 12,000.
In this embodiment, the molecular weight of the polyamine compound can be measured by a boiling point elevation method or a viscosity method.

From the viewpoint of further improving the gas barrier performance after retort treatment, (the number of moles of amino groups contained in the polyamine compound in the mixture)/(the number of moles of -COO- groups contained in the polycarboxylic acid in the mixture) is preferably 0.20 or more, more preferably 0.25 or more, even more preferably 0.30 or more, still more preferably 0.35 or more, and even more preferably 0.40 or more.
From the same viewpoint, (the number of moles of amino groups contained in the polyamine compound in the mixture)/(the number of moles of -COO- groups contained in the polycarboxylic acid in the mixture) is preferably 0.90 or less, more preferably 0.85 or less, even more preferably 0.80 or less, still more preferably 0.75 or less, and even more preferably 0.70 or less.
Although the details of the reason for this are not clear, it is believed that a gas barrier layer 103 having excellent gas barrier performance after retort treatment and a gas barrier laminate having the same can be obtained because amide crosslinking by the amino groups constituting the polyamine compound and metal crosslinking by the polyvalent metal constituting the salt of polycarboxylic acid and polyvalent metal form a well-balanced and dense structure.

(Polyvalent metal compounds)
Specifically, the polyvalent metal compound is a metal or metal compound belonging to Groups 2 to 13 of the periodic table, and more specifically, divalent or higher metals such as magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), aluminum (Al), etc., and oxides, hydroxides, halides, carbonates, phosphates, phosphites, hypophosphites, sulfates, or sulfites of these metals, etc. From the viewpoint of water resistance, impurities, etc., metal oxides or metal hydroxides are preferred.

From the viewpoint of further improving the gas barrier performance after retort treatment, the divalent or higher metal in the polyvalent metal compound is preferably one or more metals selected from the group consisting of Zn, Ca, Mg, Ba and Al, and more preferably Zn.
From a similar viewpoint, the polyvalent metal compound is preferably a compound of one or more divalent or higher metals selected from the group consisting of Zn, Ca, Mg, Ba and Al, and more preferably a compound of Zn.
From a similar viewpoint, the polyvalent metal compound is preferably one or more compounds selected from the group consisting of oxides such as magnesium oxide, calcium oxide, barium oxide, zinc oxide, and magnesium hydroxide, and hydroxides such as calcium hydroxide, barium hydroxide, and zinc hydroxide, more preferably at least one of zinc oxide and zinc hydroxide, and even more preferably zinc oxide.

In the present embodiment, from the viewpoint of further improving the gas barrier performance after retort treatment, (the number of moles of polyvalent metal compound in the mixture)/(the number of moles of -COO- groups contained in the polycarboxylic acid in the mixture) is preferably 0.10 or more, more preferably 0.13 or more, even more preferably 0.15 or more, and still more preferably 0.18 or more.
From the same viewpoint, (the number of moles of polyvalent metal compound in the mixture)/(the number of moles of -COO- groups contained in polycarboxylic acid in the mixture) is preferably 0.80 or less, more preferably 0.70 or less, even more preferably 0.60 or less, still more preferably 0.55 or less, and even more preferably 0.50 or less.

In the present embodiment, from the viewpoint of further improving the gas barrier performance after retort treatment, (the number of moles of polyvalent metal compound in the mixture)/(the number of moles of amino groups derived from the polyamine compound in the mixture) is preferably 0.25 or more, more preferably 0.35 or more, and even more preferably 0.40 or more.
From the same viewpoint, (the number of moles of polyvalent metal compound in the mixture)/(the number of moles of amino groups derived from the polyamine compound in the mixture) is preferably 0.65 or less, more preferably 0.60 or less, and even more preferably 0.55 or less.

(Phosphorus compound or its salt)
The phosphorus compound in the phosphorus compound or salt thereof contains one or more -P-OH groups in the molecular structure. The phosphorus compound may be incorporated into the mixture as a salt.
From the viewpoint of further improving the water vapor barrier property after retort treatment, the phosphorus compound preferably contains two or more -P-OH groups, more preferably contains three or more -P-OH groups. Also, from the viewpoint of improving the liquid stability of the gas barrier coating material, the number of -P-OH groups in the phosphorus compound may be, for example, two or less.

Specific examples of phosphorus compounds include phosphoric acid, phosphorous acid, phosphonic acid, hypophosphorous acid, polyphosphoric acid, and derivatives thereof.
Specifically, polyphosphoric acid has a condensation structure of two or more phosphoric acids in the molecular structure, and examples thereof include diphosphoric acid (pyrophosphoric acid), triphosphoric acid, and polyphosphoric acid in which four or more phosphoric acids are condensed.
Specific examples of the derivatives include esters of the above phosphorus compounds such as phosphorylated starch and phosphate cross-linked starch;
Halides such as chlorides;
Examples of such compounds include anhydrides such as tetraphosphorus decaoxide; and compounds having a structure in which a hydrogen atom bonded to a phosphorus atom is substituted with an alkyl group, such as nitrilotris(methylenephosphonic acid) and N,N,N',N'-ethylenediaminetetrakis(methylenephosphonic acid).

From the viewpoint of further improving the balance between barrier properties and productivity, the phosphorus compound is one or more selected from the group consisting of phosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, phosphonic acid, and salts thereof, and more preferably at least one selected from the group consisting of phosphoric acid and phosphorous acid.

Specific examples of the salt of the phosphorus compound include salts of monovalent metals such as sodium and potassium; and ammonium salts. From the viewpoint of improving the barrier properties, the salt of the phosphorus compound is preferably an ammonium salt.

In this embodiment, from the viewpoint of improving the barrier property, (the number of moles of P atoms derived from the phosphorus compound or its salt in the mixture)/(the number of moles of -COO- groups derived from the polycarboxylic acid in the mixture) may be, for example, 0.0001 or more, preferably 0.001 or more, more preferably 0.003 or more, and even more preferably 0.005 or more. In a phosphorus compound containing one P atom in its chemical formula such as phosphoric acid, the number of moles of P atoms and the number of moles of the phosphorus compound have the same meaning.
Furthermore, from the viewpoint of improving the liquid stability of the barrier coating material (mixture), (the number of moles of P atoms derived from a phosphorus compound or a salt thereof in the mixture)/(the number of moles of -COO- groups derived from a polycarboxylic acid in the mixture) is preferably 0.3 or less, more preferably 0.1 or less, even more preferably 0.08 or less, and even more preferably 0.005 or less.

The mixture before curing may contain ingredients other than those mentioned above.
For example, the mixture preferably further contains a carbonate-based ammonium salt. The carbonate-based ammonium salt is added to make the polyvalent metal compound into a polyvalent metal ammonium carbonate complex, thereby improving the solubility of the polyvalent metal compound and preparing a homogeneous solution containing the polyvalent metal compound. By including the carbonate-based ammonium salt in the mixture before curing, the amount of the polyvalent metal compound dissolved can be increased, and as a result, the mixture containing the polyvalent metal compound can be made more homogeneous.
Examples of the carbonate-based ammonium salt include ammonium carbonate and ammonium hydrogen carbonate, with ammonium carbonate being preferred since it is easily volatile and unlikely to remain in the resulting gas barrier layer.
From the viewpoint of further improving the solubility of the polyvalent metal compound, (the number of moles of carbonate-based ammonium salt in the mixture)/(the number of moles of polyvalent metal compound in the mixture) is preferably 0.05 or more, more preferably 0.10 or more, even more preferably 0.25 or more, still more preferably 0.50 or more, and even more preferably 0.75 or more.
From the viewpoint of further improving the coatability of the gas barrier coating material, the ratio (the number of moles of carbonate-based ammonium salt in the gas barrier coating material)/(the number of moles of polyvalent metal compound in the gas barrier coating material) is preferably 10.0 or less, more preferably 5.0 or less, even more preferably 2.0 or less, and even more preferably 1.5 or less.

In addition, the mixture before curing preferably further contains a surfactant from the viewpoint of suppressing the occurrence of repellency when applied as a gas barrier coating material.
The amount of the surfactant added is preferably 0.01 to 3 mass %, and more preferably 0.01 to 1 mass %, when the total solid content of the mixture is taken as 100 mass %.

Examples of surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. From the viewpoint of obtaining good coating properties, nonionic surfactants are preferred, polyoxyalkylene alkyl ethers are more preferred, and polyoxyethylene alkyl ethers are even more preferred.

Examples of nonionic surfactants include polyoxyalkylene alkyl aryl ethers, polyoxyalkylene alkyl ethers, polyoxyalkylene fatty acid esters, sorbitan fatty acid esters, silicone surfactants, acetylene alcohol surfactants, and fluorine-containing surfactants.

Examples of the polyoxyalkylene alkylaryl ethers include polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, and polyoxyethylene dodecylphenyl ether.
Examples of the polyoxyalkylene alkyl ethers include polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether and polyoxyethylene lauryl ether.
Examples of the polyoxyalkylene fatty acid esters include polyoxyethylene oleate, polyoxyethylene laurate, and polyoxyethylene distearate.
Examples of sorbitan fatty acid esters include sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, and polyoxyethylene stearate.
An example of the silicone surfactant is dimethylpolysiloxane.
Examples of the acetylene alcohol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, and 3,5-dimethyl-1-hexyne-3-ol.
The fluorine-containing surfactant may, for example, be a fluorine alkyl ester.

The mixture before curing may contain additives other than those mentioned above. For example, various additives such as lubricants, slip agents, antiblocking agents, antistatic agents, antifogging agents, pigments, dyes, inorganic or organic fillers, etc. may be added.

The solids concentration of the mixture before curing is preferably 0.5 to 15% by mass, and more preferably 1 to 10% by mass, from the viewpoint of improving the coatability when applied as a gas barrier coating material.

(Method for producing gas barrier layer)
Specifically, the gas barrier layer 103 can be produced by applying a pre-cured mixture (gas barrier coating material) and curing it.
The mixture can be obtained as follows:
First, a volatile base is added to a polycarboxylic acid to completely or partially neutralize the carboxyl groups of the polycarboxylic acid, and then a polyvalent metal salt compound and an appropriate carbonate-based ammonium salt are mixed to form metal salts at all or part of the carboxyl groups of the polycarboxylic acid neutralized with the volatile base and at the carboxyl groups of the polycarboxylic acid not neutralized with the volatile base.
Then, a polyamine compound is further added, and finally, a phosphorus compound or a salt thereof is added to obtain a pre-curing mixture, whereby a salt is formed between the phosphorus compound and the amino group of the polyvalent metal compound or polyamine.
By mixing the polycarboxylic acid, the polyvalent metal salt compound, the phosphorus compound or its salt, the appropriate carbonate-based ammonium salt, and the polyamine compound in this manner, it is possible to suppress the formation of aggregates and obtain a more uniform mixture, which makes it possible to more effectively advance the dehydration condensation reaction between the -COO- group contained in the polycarboxylic acid and the amino group contained in the polyamine compound.

More specifically, the method is as follows. In the following, an example in which a volatile base and a carbonate-based ammonium salt are blended in the mixture will be described.
First, a solution in which the carboxy groups constituting the polycarboxylic acid are completely or partially neutralized is prepared.
A volatile base is added to a polycarboxylic acid to completely or partially neutralize the carboxyl groups of the polycarboxylic acid. Neutralizing the carboxyl groups of the polycarboxylic acid effectively prevents gelation caused by the reaction between the carboxyl groups constituting the polycarboxylic acid and the amino groups constituting the polyvalent metal compound or polyamine compound when the polyvalent metal compound or polyamine compound is added, and a more uniform mixture can be obtained.
Next, a polyvalent metal salt compound and a carbonate-based ammonium salt are added and dissolved, and the resulting polyvalent metal ions form a polyvalent metal salt with the -COO- group constituting the polycarboxylic acid. In this case, the -COO- group that forms a salt with the polyvalent metal ion refers to both a carboxy group that has not been neutralized with the above-mentioned base and a -COO- group that has been neutralized with a base. In the case of a -COO- group that has been neutralized with a base, the polyvalent metal ion derived from the above-mentioned polyvalent metal compound is coordinated in a replaceable manner to form a polyvalent metal salt of the -COO- group.
After the polyvalent metal salt is formed, a polyamine compound and a phosphorus compound or a salt thereof are further added to obtain a mixture. At this time, the polyvalent metal salt coordinated to the -COO- group also coordinates to the -P- ^O- group in the phosphorus compound to form a -COO-polyvalent metal-O-P- structure. In addition, an ionic bond is formed between the _-NH2 group in the polyamine and the -P-O- ^group in the phosphorus compound.

The mixture thus produced is applied as a gas barrier coating material onto the inorganic layer 102 or onto the intermediate layer between the inorganic layer 102 and the gas barrier layer 103 formed on the inorganic layer 102, and then dried and cured to form the gas barrier layer 103. At this time, the polyvalent metal of the polyvalent metal salt of the -COO- group constituting the polycarboxylic acid forms a metal bridge, the amino group constituting the polyamine forms an amide bridge, and the -P- ^O- group in the phosphorus compound forms an ionic bridge with the polyvalent metal or the amino group in the polyamine, thereby obtaining the gas barrier layer 103 having excellent gas barrier properties. A more detailed method for producing the gas barrier layer 103 will be described later.

From the viewpoint of improving the barrier properties, the thickness of the gas barrier layer 103 after drying and curing is preferably 0.01 μm or more, more preferably 0.05 μm or more, and further preferably 0.1 μm or more.
From the viewpoint of reducing the overall thickness of the gas barrier laminate, the thickness of the gas barrier layer 103 after drying and curing is preferably 15 μm or less, more preferably 5 μm or less, and further preferably 1 μm or less.

(Base layer)
The base layer 101 may be a single layer or two or more layers. The shape of the base layer 101 is not limited, and examples thereof include a sheet or film shape, a tray, a cup, a hollow body, and the like.

The material of the base layer 101 is not limited, and any material can be used as long as it can stably form the inorganic layer 102 on the base layer 101 and can coat the upper part of the inorganic layer 102 with a solution of a gas barrier coating material. Examples of the material of the base layer 101 include organic materials such as resins such as thermosetting resins and thermoplastic resins, and paper; inorganic materials such as glass, pottery, ceramics, silicon oxide, silicon oxynitride, silicon nitride, cement, aluminum, aluminum oxide, iron, copper, stainless steel, and other metals; and base layers of a multilayer structure consisting of a combination of organic materials or organic materials and inorganic materials. Among these, for example, in the case of various film applications such as packaging materials and panels, plastic films using at least one selected from the group consisting of thermosetting resins and thermoplastic resins, or organic materials such as paper are preferred.

As the thermosetting resin, known thermosetting resins can be used. Examples include epoxy resin, unsaturated polyester resin, phenolic resin, urea-melamine resin, polyurethane resin, silicone resin, polyimide, etc.

As the thermoplastic resin, known thermoplastic resins can be used. Examples include polyolefins (polyethylene, polypropylene, poly(4-methyl-1-pentene), poly(1-butene), etc.), polyesters (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamides (nylon-6, nylon-66, polymethaxylene adipamide, etc.), polyvinyl chloride, polyimide, ethylene-vinyl acetate copolymers or saponified products thereof, polyvinyl alcohol, polyacrylonitrile, polycarbonate, polystyrene, ionomers, fluororesins, and mixtures thereof.

Among these, from the viewpoint of improving transparency, one or more resins selected from the group consisting of polypropylene, polyethylene terephthalate (PET), polyethylene naphthalate, polyamide, polyimide, and polybutylene terephthalate are preferred.
From the viewpoint of excellent pinhole resistance, tear resistance, heat resistance, etc., one or more resins selected from the group consisting of polyamide, polyethylene terephthalate, and polybutylene terephthalate are preferred. From the same viewpoint, the base layer 101 is preferably a layer containing one or more resins selected from the group consisting of polyamide, polyethylene terephthalate, and polybutylene terephthalate, and more preferably a layer of one or more of these resins.

In addition, when a hygroscopic material such as polyamide is used for the base layer 101, the base layer 101 in the gas barrier laminate absorbs moisture and swells, which tends to reduce the gas barrier performance under high humidity, the gas barrier performance after retort treatment, and the gas barrier performance when filled with acidic contents. However, in this embodiment, even when a hygroscopic material is used for the base layer 101, the gas barrier laminate can be prevented from reducing the gas barrier performance under high humidity and the gas barrier performance after retort treatment.

Alternatively, the base layer 101 may be formed by stretching a film made of a thermosetting resin or a thermoplastic resin at least in one direction, and preferably in two axial directions.
From the viewpoint of excellent transparency, rigidity and heat resistance, the base layer 101 is preferably a biaxially stretched film formed from one or more thermoplastic resins selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide and polybutylene terephthalate, and more preferably a biaxially stretched film formed from one or more thermoplastic resins selected from the group consisting of polyamide, polyethylene terephthalate and polybutylene terephthalate.

Furthermore, the surface of the base layer 101 may be coated with polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, acrylic resin, urethane resin, or the like.
Furthermore, the base layer 101 may be subjected to a surface treatment in order to improve adhesion to the gas barrier layer 103. Specifically, the surface of the base layer 101 facing the gas barrier layer 103 may be subjected to a surface activation treatment such as a corona treatment, a flame treatment, a plasma treatment, or a primer coat treatment.

From the viewpoint of obtaining good film characteristics, the thickness of the base layer 101 is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, and is preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 300 μm or less.

(Inorganic Layer)
Examples of inorganic materials constituting the inorganic layer 102 include metals, metal oxides, metal nitrides, metal fluorides, and metal oxynitrides that can form thin films having barrier properties.
Examples of inorganic materials constituting the inorganic layer 102 include one or more selected from simple substances, oxides, nitrides, fluorides, and oxynitrides of elements in Group 2A of the periodic table, such as beryllium, magnesium, calcium, strontium, and barium; transition elements in the periodic table, such as titanium, zirconium, ruthenium, hafnium, and tantalum; elements in Group 2B of the periodic table, such as zinc; elements in Group 3A of the periodic table, such as aluminum, gallium, indium, and thallium; elements in Group 4A of the periodic table, such as silicon, germanium, and tin; and elements in Group 6A of the periodic table, such as selenium and tellurium.
In this embodiment, the group names of the periodic table for the inorganic layer 102 are shown in the old CAS system.

Furthermore, among the above inorganic substances, one or more inorganic substances selected from the group consisting of silicon oxide, aluminum oxide, and aluminum are preferred, as they have an excellent balance between barrier properties, costs, and the like, and aluminum oxide is more preferred.
The silicon oxide may contain silicon monoxide and silicon suboxide in addition to silicon dioxide.

The inorganic layer 102 is formed from the above-mentioned inorganic materials. The inorganic layer 102 preferably includes an aluminum oxide layer made of aluminum oxide, since this has an excellent balance between barrier properties, cost, and the like.
The inorganic layer 102 may be composed of a single inorganic layer or may be composed of multiple inorganic layers. In addition, when the inorganic layer 102 is composed of multiple inorganic layers, the inorganic layers may be the same type or different types.

From the viewpoint of a balance between improved barrier properties and improved ease of handling, the thickness of the inorganic layer 102 is usually 1 nm or more, preferably 4 nm or more, and usually 1000 nm or less, preferably 500 nm or less.
Here, the thickness of the inorganic layer 102 can be determined from an image observed by, for example, a transmission electron microscope or a scanning electron microscope.

The method of forming the inorganic layer 102 is not limited, and for example, the inorganic layer 102 can be formed on one or both sides of the base layer 101 by vacuum deposition, ion plating, sputtering, chemical vapor deposition, physical vapor deposition, chemical vapor deposition (CVD), plasma CVD, sol-gel, etc. Among them, film formation under reduced pressure by sputtering, ion plating, chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma CVD, etc. is preferable. It is expected that the smoothness of the surface of the inorganic layer 102 can be improved and the number of holes can be reduced by the rapid reaction of chemically active molecular species containing silicon, such as silicon nitride and silicon oxynitride. In order to perform these bonding reactions quickly, it is desirable that the inorganic atoms or compounds are chemically active molecular species or atomic species.
From the viewpoint of improving the balance between the barrier properties of the gas barrier laminate and the productivity, the inorganic layer 102 is preferably a vapor-deposited film.

The inorganic layer 102 is a vapor-deposited film provided on the base layer 101, or on an intermediate layer if there is one between the base layer 101 and the inorganic layer 102, from the viewpoint of improving the balance between the barrier properties and productivity of the gas barrier laminate, and is composed of one or more inorganic substances selected from the group consisting of silicon oxide, aluminum oxide, and aluminum.

(Undercoat Layer)
An undercoat layer 104 may be provided between the base layer 101 and the inorganic layer 102 (FIG. 2). By providing the undercoat layer 104, the adhesion between them can be further improved, and the barrier property after retort treatment can be further improved.

From the viewpoint of improving the adhesion between the base layer 101 and the inorganic layer 102, the material of the undercoat layer 104 may be, for example, one or more selected from the group consisting of polyurethane resin, polyester resin, oxazoline resin, and (meth)acrylic resin.

Examples of polyurethane resins include various polyurethane resins, polyurethane polyurea resins, and prepolymers thereof. Specific examples of such urethane resins include reaction products of diisocyanate components such as tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, and dicyclohexyl diisocyanate with diol components such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane dimethanol, bisphenol, polyester diol, polyether diol, polycarbonate diol, and polyethylene glycol; reaction products of urethane prepolymers having isocyanate groups at their terminals with amino compounds, aminosulfonates, polyhydroxycarboxylic acids, bisulfites, and the like.

In order to further improve the barrier properties after retort treatment and the adhesion between the base layer 101 and the inorganic layer 102, it is also preferable that the polyurethane resin in the undercoat layer 104 is composed of a polyurethane resin having an aromatic ring structure in the main chain. The polyurethane resin having an aromatic ring structure in the main chain can be obtained as a water-dispersible polyurethane resin by, for example, reacting a polyol, an organic polyisocyanate, and a chain extender. This allows the aromatic ring structure to be introduced into the main chain of the polyurethane resin.
More specifically, as the polyurethane resin having an aromatic ring structure in the main chain, those described in JP-A-2018-171827 can be used.

The water-dispersible polyurethane resin may be used in combination with a crosslinking agent to improve heat resistance, water resistance, hydrolysis resistance, and the like. The crosslinking agent may be an external crosslinking agent added to the water-dispersible polyurethane resin as a third component, or an internal crosslinking agent that introduces reactive points that will become crosslinked structures into the molecular structure of the water-dispersible polyurethane resin.

As the crosslinking agent, a compound having an isocyanate group, an oxazoline group, a carbodiimide group, an epoxy group, a melamine resin, a silanol group, or the like can be suitably used, and a compound having a carbodiimide group is more suitable. When a compound having a carbodiimide group is used as the crosslinking agent, the amount of the compound having a carbodiimide group added is preferably an amount such that the carbodiimide group is 0.1 to 3.0 mol, more preferably 0.2 to 2.0 mol, and even more preferably 0.3 to 1.0 mol per 1.0 mol of carboxyl groups in the polyurethane resin.

Examples of polyester resins used in the undercoat layer 104 include various polyester resins and their modified products. Specific examples of such polyester resins include reaction products of polycarboxylic acid components such as terephthalic acid, phthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, 2-sulfoisophthalic acid, 5-sulfoisophthalic acid, adipic acid, sebacic acid, succinic acid, and dodecanedioic acid with diol components such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol, and bisphenol, as well as modified products with acrylic resins, epoxy resins, and the like.

When an oxazoline resin is used for the undercoat layer 104, the undercoat layer 104 is preferably composed of an oxazoline-based resin composition containing an oxazoline group-containing aqueous polymer, an aqueous (meth)acrylic resin, and an aqueous polyester resin.
The oxazoline-based resin composition is composed of, for example, an oxazoline group-containing aqueous polymer having an oxazoline group content of 6.0 to 9.0 mmol/g, an aqueous (meth)acrylic resin having a carboxy group content of 0.5 to 3.5 mmol/g, and an aqueous polyester resin having a carboxy group content of 0.5 to 2.0 mmol/g.
The oxazoline-based resin composition contains, for example, 10 to 55 mass% of the oxazoline group-containing aqueous polymer, 10 to 80 mass% of the aqueous (meth)acrylic resin, and 10 to 80 mass% of the aqueous polyester resin, where the total amount of the oxazoline group-containing aqueous polymer, the aqueous (meth)acrylic resin, and the aqueous polyester resin is 100 mass%.
In the oxazoline resin composition, for example, the ratio of the number of moles of oxazoline groups to the number of moles of carboxy groups [expressed as the ratio (x/y) of the number of moles of oxazoline groups (x mmol) to the number of moles of carboxy groups (y mmol) × 100 [mol %]] is 150 to 420 mol %.
More specifically, the oxazoline resin used in the undercoat layer 104 may be one described in WO 2016/186074.

From the viewpoint of obtaining good adhesion, the thickness of the undercoat layer 104 is preferably 0.001 μm or more, more preferably 0.005 μm or more, even more preferably 0.01 μm or more, even more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and still more preferably 0.2 μm or more.
Also, from an economical standpoint, the thickness of undercoat layer 104 is preferably 1.0 μm or less, more preferably 0.6 μm or less, and even more preferably 0.5 μm or less, and may be, for example, 0.1 μm or less, or, for example, 0.05 μm or less.

(Adhesive Layer)
The gas barrier laminate may further include an adhesive layer, the adhesive layer being exclusive of the undercoat layer 104.
The adhesive layer is provided, for example, between the gas barrier layer 103 and an upper layer of the gas barrier layer 103. When the upper layer is formed of a plurality of layers, an adhesive layer may be provided between the plurality of layers. Here, the upper layer of the gas barrier layer 103 refers to a layer laminated on the surface of the gas barrier layer 103 opposite to the surface facing the inorganic layer 102.
The adhesive layer may contain a known adhesive. Examples of the adhesive include laminating adhesives composed of organic titanium resins, polyethyleneimine resins, urethane resins, epoxy resins, acrylic resins, polyester resins, oxazoline group-containing resins, modified silicone resins, alkyl titanates, polyester polybutadienes, etc., or one-liquid or two-liquid polyols and polyisocyanates, water-based urethanes, ionomers, etc. Alternatively, aqueous adhesives whose main raw materials are acrylic resins, vinyl acetate resins, urethane resins, polyester resins, etc. may be used.
Furthermore, other additives such as a curing agent and a silane coupling agent may be added to the adhesive depending on the application of the gas barrier laminate 100. When the gas barrier laminate is used for hot water treatment such as retort, from the viewpoint of heat resistance and water resistance, a dry lamination adhesive such as a polyurethane adhesive is preferred, and a solvent-based two-component curing type polyurethane adhesive is more preferred.

(Method for producing gas barrier laminate)
In this embodiment, the method for producing the gas barrier laminate 100 includes, for example, a step of preparing a base layer 101, a step of forming an inorganic layer 102 on the base layer 101, and a step of forming a gas barrier layer 103 on the base layer 101 on which the inorganic layer 102 has been formed. In addition, after the step of forming the inorganic layer 102 and before the step of forming the gas barrier layer 103, the method may further include a step of forming an undercoat layer 104 on the inorganic layer 102.

The process of forming the inorganic layer 102 on the substrate layer 101 can use, for example, the method of forming the inorganic layer 102 described above.

The process of forming the gas barrier layer 103 includes, for example, a process of applying the pre-cured mixture as a gas barrier coating material to the inorganic layer 102, followed by drying to obtain a coating layer, and a process of heating the coating layer to cause a dehydration condensation reaction between the carboxy group contained in the polycarboxylic acid and the amino group contained in the polyamine compound, thereby forming the gas barrier layer 103 having an amide bond.

The method for applying the gas barrier coating material to the inorganic layer 102 is not limited, and any conventional method can be used. For example, a coating method using a known coating machine such as a Mayer bar coater, air knife coater, direct gravure coater, gravure offset, arc gravure coater, gravure reverse, or jet nozzle type gravure coater, a top feed reverse coater, bottom feed reverse coater, or nozzle feed reverse coater, or a reverse roll coater, a five-roll coater, a lip coater, a bar coater, a bar reverse coater, or a die coater can be used.

From the viewpoint of improving the barrier performance of the resulting gas barrier laminate, the coating amount (wet thickness) is preferably 0.05 μm, and more preferably 1 μm or more.
From the viewpoint of preventing curling of the obtained gas barrier laminate and from the viewpoint of more effectively promoting the dehydration condensation reaction between the -COO- group contained in the polycarboxylic acid and the amino group contained in the polyamine compound, the wet thickness is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less.

The drying and heat treatment may be carried out after drying, or may be carried out simultaneously.
The method of drying and heat treatment is not limited as long as it can obtain the effects of the present invention, and may be any method capable of curing the gas barrier coating material and heating the cured gas barrier coating material. For example, convection heat transfer such as ovens and dryers, conductive heat transfer such as heating rolls, radiation heat transfer using electromagnetic waves such as infrared, far-infrared and near-infrared heaters, and internal heat generation such as microwaves are included. As the device used for drying and heat treatment, a device capable of both drying and heat treatment is preferable from the viewpoint of manufacturing efficiency. Among them, specifically, it is preferable to use a hot air oven from the viewpoint of being usable for various applications such as drying, heating, and annealing, and it is also preferable to use a heating roll from the viewpoint of excellent heat conduction efficiency to the film. In addition, the methods used for drying and heat treatment may be appropriately combined. Specifically, a hot air oven and a heating roll may be used in combination. For example, if the gas barrier coating material is dried in a hot air oven and then heat treatment is performed with a heating roll, the heat treatment process becomes short, which is preferable from the viewpoint of manufacturing efficiency. In addition, it is preferable to perform drying and heat treatment only with a hot air oven.

The heat treatment conditions are, for example, a heat treatment temperature of 80 to 250° C. and a heat treatment time of 1 second to 10 minutes, preferably a heat treatment temperature of 120 to 240° C. and a heat treatment time of 1 second to 1 minute, more preferably a heat treatment temperature of 170 to 230° C. and a heat treatment time of 1 second to 30 seconds, and even more preferably a heat treatment temperature of 200 to 220° C. and a heat treatment time of 1 second to 10 seconds. Furthermore, as described above, the use of a heating roll in combination enables heat treatment in a short time.
In order to effectively promote the dehydration condensation reaction between the -COO- group contained in the polycarboxylic acid and the amino group contained in the polyamine compound, it is important to adjust the heat treatment temperature and heat treatment time according to the wet thickness of the gas barrier coating material. By selecting an appropriate heat treatment temperature and heat treatment time, an appropriate crosslinked structure is formed.

When the gas barrier coating material is dried and heat-treated, the carboxyl groups of the polycarboxylic acid react with the polyamine or polyvalent metal compound, forming covalent bonds and ionic crosslinks, forming a gas barrier layer 103 that has good gas barrier properties even after retort treatment.

In this embodiment, the gas barrier laminate has excellent gas barrier performance and can be suitably used as a packaging material, particularly as a food packaging material for contents that require high gas barrier properties, as well as a variety of packaging materials for medical applications, industrial applications, and everyday miscellaneous goods applications.

The gas barrier laminate of this embodiment can be suitably used, for example, as a vacuum insulation film, a sealing film for sealing electroluminescence elements, solar cells, etc., where high barrier performance is required.

In this embodiment, specific examples of the laminate structure including the gas barrier laminate are shown below.
(Laminated Structure Example 1) Substrate layer 101 (PET substrate)/inorganic layer 102 (alumina vapor deposition layer)/gas barrier layer 103/adhesive layer/polyolefin layer (Laminated Structure Example 2) Substrate layer 101 (PET substrate)/undercoat layer 104/inorganic layer 102 (alumina vapor deposition layer)/gas barrier layer 103/adhesive layer/polyolefin layer (Laminated Structure Example 3) Substrate layer 101 (PET substrate)/inorganic layer 102 (alumina vapor deposition layer)/gas barrier layer 103/adhesive layer/polyamide layer/adhesive layer/polyolefin layer (Laminated Structure Example 4) Substrate layer 101 (PET substrate)/undercoat layer 104/inorganic layer 102 (alumina vapor deposition layer)/gas barrier layer 103/adhesive layer/polyamide layer/adhesive layer/polyolefin layer Here, by including a polyolefin layer composed of a polyolefin such as polyethylene, polypropylene, poly(4-methyl-1-pentene) or poly(1-butene) in the laminate structure, the gas barrier laminate can have good pinhole resistance, tear resistance, heat resistance, etc., while further suppressing the deterioration of the gas barrier performance under high humidity and after retort treatment.

The above describes the embodiments of the present invention with reference to the drawings, but these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

The present embodiment will be described in detail below with reference to examples and comparative examples. Note that the present embodiment is not limited in any way to the descriptions of these examples.

Example 1
(1) Preparation of a gas barrier coating material 10% ammonia water (manufactured by Wako Pure Chemical Industries, Ltd.) was added to the carboxyl groups of polyacrylic acid (manufactured by Toagosei Co., Ltd., product name: AC-10H, weight average molecular weight: 800,000) so that the ammonia content was 150 equivalent %, and purified water was further added to obtain an aqueous solution of ammonium polyacrylate with a concentration of 7.29 mass %.
Next, zinc oxide (manufactured by Kanto Chemical Co., Ltd.) and ammonium carbonate were added to the obtained aqueous ammonium polyacrylate solution, mixed and stirred to prepare a mixed solution (A). Here, the amount of zinc oxide added was an amount such that (the number of moles of zinc oxide in the gas barrier coating material)/(the number of moles of -COO- groups contained in the polyacrylic acid in the gas barrier coating material) was the value shown in the ZnO/PAA column in Table 1. In addition, the amount of ammonium carbonate was an amount such that (the number of moles of carbonate-based ammonium salt in the gas barrier coating material)/(the number of moles of zinc oxide in the gas barrier coating material) was 1.0.
Next, purified water was added to polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., product name: SP-200, number average molecular weight: 10,000) to obtain a 10% polyethyleneimine aqueous solution.
Also, purified water was added to diammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ , manufactured by Kanto Chemical Co., Ltd.) to prepare a 10% aqueous solution.
Next, the above mixed solution (A), the above polyethyleneimine aqueous solution and the above diammonium hydrogen phosphate solution were mixed in a ratio such that (the number of moles of amino groups contained in the polyethyleneimine in the gas barrier coating material)/(the number of moles of -COO- groups contained in the polyacrylic acid in the gas barrier coating material) was the value shown in the PEI/PAA column in Table ₁ , and (the number of moles of ( _NH4 ) _2HPO4 )/(the number of moles of -COO- groups contained in the polyacrylic acid) was the value shown in the addition amount in the acid compound/PAA column in Table 1, to prepare mixed solution (B).
Further, purified water was added so that the solid content of the mixed solution (B) became 1.5%, and the mixture was stirred until a homogeneous solution was obtained. Then, an activator (manufactured by Kao Corporation, product name: Emulgen 120) was mixed in so that the concentration of the solid content of the mixed solution (B) became 0.3 mass % to prepare a gas barrier coating material.

(2) Preparation of Gas Barrier Laminate A biaxially oriented polyethylene terephthalate film (PET12, manufactured by Unitika Ltd.) having a thickness of 12 μm was used as a substrate. A resin composition having the following composition was applied to one side (corona-treated side) of the substrate using a Mayer bar and then dried to form an undercoat (UC) layer having a thickness of 0.20 μm after drying.
(composition)
Base material: Polyurethane resin aqueous dispersion (manufactured by Mitsui Chemicals, product name: Takelac WS-4033, aromatic polyester type polyurethane resin)
Crosslinking agent: Compound having a carbodiimide group (manufactured by Nisshinbo Chemical Co., Ltd., product name: Carbodilite SV-02)
Blending ratio: The crosslinking agent was blended into the base material such that the carbodiimide groups in the crosslinking agent were 0.4 mol per 1.0 mol of carboxyl groups in the polyurethane resin in the base material.
Next, an alumina vapor deposition layer was formed on the undercoat layer by the following method.
A 7-nm-thick aluminum oxide film was formed on the UC layer by heating and evaporating aluminum using a high-frequency induction heating method, and then vapor-depositing the aluminum while introducing oxygen. This resulted in an aluminum oxide-deposited PET film. The water vapor permeability of this aluminum oxide-deposited PET film was 1.5 g/( ^m2 ·24 h).
The gas barrier coating material obtained in step (1) was applied onto the deposition layer using a Mayer bar so that the coating thickness after drying was 0.2 μm, and a gas barrier laminate was obtained by heat-treating the coating material using a hot air dryer under the conditions shown in the heat treatment column in Table 1. The preparation conditions are shown in Table 1.

(3) Analysis of Gas Barrier Layer The gas barrier layer of the gas barrier laminate obtained in the above step (2) was subjected to infrared absorption spectrum analysis by the ATR method described below.
The infrared absorption spectrum was measured (infrared total reflection measurement: ATR method) using a JASCO IRT-5200 device equipped with a PKM-GE-S (Germanium) crystal under the conditions of an incident angle of 45 degrees, room temperature, a resolution of 4 cm ^-1 , and an accumulation count of 100. The obtained absorption spectrum was analyzed by the method described above to determine the maximum peaks α and γ, and to calculate the total peak areas A to D. Then, the area ratios B/A, C/A, and D/A were calculated from the total peak areas A to D.
The results of the infrared absorption spectrum analysis by the ATR method are shown in Table 2.

(4) Preparation of a two-layer laminate structure An adhesive was applied to the corona discharge treated surface of a 70 μm thick non-oriented polypropylene (manufactured by Mitsui Chemicals Tohcello, product name: RXC-22) and laminated to the gas barrier surface (the surface on the gas barrier layer side, the same applies below) of the gas barrier laminate obtained in the above step (2) to prepare a two-layer laminate structure. The adhesive used was a mixture of 9 parts by mass of Mitsui Chemicals' product name: Takelac A525S, 1 part by mass of an isocyanate-based curing agent (manufactured by Mitsui Chemicals, product name: Takenate A50) and 7.5 parts by mass of ethyl acetate.

(5) Preparation of a three-layer laminate structure First, an adhesive was applied to the corona discharge treated surface of a 60 μm thick non-oriented polypropylene (manufactured by Mitsui Chemicals Tohcello, Inc., product name: RXC-22), and a 15 μm thick nylon film (manufactured by Unitika Ltd., product name: (Emblem ONBC)) was laminated to prepare a laminate.
An adhesive was applied to the nylon film surface of the laminate, and the laminate was bonded to the gas barrier surface of the gas barrier laminate obtained in the above step (2) to prepare a three-layer laminate structure. The adhesive used was the same as in the above step (4).

(6) Evaluation of gas barrier properties after retort treatment The laminated structures obtained in steps (4) and (5) were folded back so that the unstretched polypropylene was on the inner surface, and the two sides were heat-sealed to form a bag, after which 70 mL of water was placed inside as the content, and the other side was heat-sealed to form a bag, which was then retorted for 30 minutes at 130° C. in a high-temperature, high-pressure retort sterilizer. After the retort treatment, the water in the content was drained, and the sealed portion was removed to obtain a film after the retort treatment (filled with water).
The oxygen permeability [ml/( ^m2 ·day·MPa)] of the film after retort treatment obtained by the above method was measured using OX-TRAN2/21 manufactured by Mocon Co., Ltd. in accordance with JIS K 7126 under conditions of 20° C. and 90% RH.
In addition, the film after retort treatment obtained by the above method was overlapped so that the unstretched polypropylene was on the inner surface, the laminate structure was folded, and the two sides were heat-sealed to form a bag. Calcium chloride was then placed inside the bag, and the other side was heat-sealed to form a bag with a surface area of 0.01 ^m2 . This was left for 300 hours under conditions of 40°C and 90% RH, and the water vapor transmission rate [g/( ^m2 ·day)] was measured based on the change in weight before and after leaving the bag.
The results of the gas barrier property evaluation after the retort treatment are shown in Table 3.

(Examples 2 to 8)
For each Example, a gas barrier laminate and each laminate structure were obtained in the same manner as in Example 1, except that the composition of the raw materials and the preparation conditions were changed to the values shown in Table 1.
The results of the analysis performed on the gas barrier layer of the obtained gas barrier laminate in accordance with Example 1 are also shown in Table 2. In addition, the results of the evaluation of the gas barrier properties after retort treatment are also shown in Table 3.

(Comparative Example 1)
A gas barrier laminate and a three-layer laminate structure were obtained in the same manner as in Example 1, except that zinc oxide and ammonium carbonate were not used, and that the diammonium hydrogen phosphate solution was not used.
The results of the analysis performed on the gas barrier layer of the obtained gas barrier laminate in accordance with Example 1 are also shown in Table 2. In addition, the results of the evaluation of the gas barrier properties after retort treatment are also shown in Table 3.

(Example 9)
(1) Preparation of Gas Barrier Coating Material A polyacrylic acid (PAA) aqueous solution (manufactured by Toagosei Co., Ltd., product name: AC-10H, weight average molecular weight: 800,000) was diluted with purified water to prepare an aqueous solution with a PAA concentration of 10%, and 10% ammonia water was added so that the ammonia concentration was 1.5 mol relative to the carboxy group, thereby obtaining an aqueous solution of ammonium polyacrylate with a PAA concentration of 7.38%.
Next, zinc oxide (ZnO: manufactured by Kanto Chemical Co., Ltd.) and ammonium carbonate (manufactured by Kanto Chemical Co., Ltd.) were added to the obtained aqueous solution of ammonium polyacrylate, and mixed and stirred. Here, the amount of zinc oxide added was an amount such that the molar ratio of (zinc oxide)/(carboxy group of PAA) was 0.3. The amount of ammonium carbonate was an amount such that the molar ratio of the carboxy group of PAA was 0.3. In this way, a mixed solution (A) was prepared.
Next, purified water was added to polyethyleneimine (PEI: manufactured by Nippon Shokubai Co., Ltd., product name: SP-200, number average molecular weight: 10,000) to obtain an aqueous polyethyleneimine solution with a PEI concentration of 10%.
Next, the mixed solution (A) and the aqueous polyethyleneimine solution were mixed in a molar ratio of (nitrogen of PEI)/(carboxy group of PAA) of 0.55 to prepare a mixed solution (B).
Further, the above mixture (B) is added with purified water so that the solid content concentration of PAA+ZnO+PEI becomes 2%, and stirred until it becomes a uniform solution.Further, diammonium hydrogen phosphate (Kanto Chemical Co., Ltd., ( _NH4 ) _{2HPO4 )} is added with a diammonium hydrogen phosphate aqueous solution with a solid content concentration of 2% so that the diammonium hydrogen phosphate becomes ^1x10-3 mol per 1 mol of carboxyl group of PAA, and stirred, and then an activator (Kao Corporation, product name: Emulgen 120) is mixed with an activator aqueous solution with a solid content concentration of 1% so that the activator becomes 0.3 mass% per solid content of PAA+ZnO+PEI, to prepare a gas barrier coating material.

(2) Preparation of gas barrier laminate A transparent deposition film (manufactured by Mitsui Chemicals Tohcello, model number: TL-PET-H) in which aluminum oxide was deposited on a 12 μm PET film as a base layer as an inorganic layer was attached to a glass plate, and the gas barrier coating material obtained in step (1) was applied with an applicator so that the film thickness after drying was 0.2 μm, and the glass plate was dried in a hot air dryer at 120 ° C. for 5 minutes. Both ends of the dried film were fixed to make the film hollow, and then heat treatment was performed in a hot air dryer at 150 ° C. for 1 minute to form a gas barrier layer on the transparent deposition film to prepare a gas barrier laminate.
The conditions for preparing the gas barrier layer are shown in Table 1.

(3) Analysis of Gas Barrier Layer The gas barrier layer of the gas barrier laminate obtained in the above procedure (2) was subjected to the same analysis as in the procedure (3) of Example 1. The results of the analysis are shown in Table 2.

(4) Preparation of a gas barrier laminate having a two-layer laminate structure A two-layer laminate structure was prepared in the same manner as in the procedure (4) of Example 1 using the gas barrier layer of the gas barrier laminate obtained in the procedure (2) above.

(5) Preparation of a gas barrier laminate having a three-layer laminate structure A three-layer laminate structure was prepared in the same manner as in the procedure (5) of Example 1 using the gas barrier layer of the gas barrier laminate obtained in the procedure (2) above.

(6) Evaluation of gas barrier property after retort treatment The laminate structures obtained by the above steps (4) and (5) were subjected to an evaluation of gas barrier property after retort treatment in the same manner as in step (6) of Example 1. The results are shown in Table 6.

(Example 10)
A gas barrier laminate and each laminate structure were produced in accordance with Example 9, except that the concentration of diammonium hydrogen phosphate was 0.01 mol per 1 mol of the carboxyl group of polyacrylic acid. The production conditions are also shown in Table 3.
The results of the analysis performed on the gas barrier layer of the obtained gas barrier laminate in accordance with Example 9 are also shown in Table 2. In addition, the results of the evaluation of the gas barrier properties after retort treatment are also shown in Table 3.

Example 11
A gas barrier laminate and each laminate structure were produced in accordance with Example 9, except that the concentration of diammonium hydrogen phosphate was 0.03 mol per 1 mol of the carboxy group of polyacrylic acid. The production conditions are also shown in Table 1.
The results of the analysis performed on the gas barrier layer of the obtained gas barrier laminate in accordance with Example 9 are also shown in Table 2. In addition, the results of the evaluation of the gas barrier properties after retort treatment are also shown in Table 3.

As can be seen from Tables 1 to 3, in each example, whether it was a two-layer laminate or a three-layer laminate, a laminate with excellent barrier properties after retort treatment could be obtained with good productivity.

Reference Signs List 10 Gas barrier film 100 Gas barrier laminate 101 Base layer 102 Inorganic layer 103 Gas barrier layer 104 Undercoat layer 110 Gas barrier laminate

Claims (10)

A base layer;
a gas barrier layer provided on at least one surface of the base layer;
an inorganic layer provided between the base layer and the gas barrier layer;
Including,
the gas barrier layer is formed of a cured product of a mixture containing a polycarboxylic acid, a polyamine compound, a polyvalent metal compound, and a phosphorus compound having one or more -P-OH groups or a salt thereof;
(the number of moles of the polyvalent metal derived from the polyvalent metal compound in the mixture)/(the number of moles of —COO— groups derived from the polycarboxylic acid in the mixture) is 0.13 or more and 0.80 or less ,
In the infrared absorption spectrum of the gas barrier layer,
The total peak area in the absorption band range from 1493 cm ⁻¹ to 1780 cm ⁻¹ is defined as A,
The total peak area in the absorption band range of 1598 cm ⁻¹ to 1690 cm ⁻¹ is defined as B,
The total peak area in the absorption band range from 1690 cm ⁻¹ to 1780 cm ⁻¹ is defined as C,
When the total peak area in the absorption band range from 1493 cm ⁻¹ to 1598 cm ⁻¹ is D,
the area ratio of amide bonds represented by B/A is 0.200 or more and 0.370 or less,
the area ratio of carboxylic acid represented by C/A is 0.150 or less;
A gas barrier laminate , in which the area ratio of a carboxylate, represented by D/A, is 0.580 or more and 0.800 or less . The gas barrier laminate according to claim 1, further comprising an undercoat layer provided between the substrate layer and the inorganic layer. The gas barrier laminate according to claim 1 or 2, wherein the inorganic layer is a vapor-deposited film provided on the base layer, or on an intermediate layer if an intermediate layer is provided between the base layer and the inorganic layer, and is composed of one or more inorganic substances selected from the group consisting of silicon oxide, aluminum oxide, and aluminum. In the infrared absorption spectrum of the gas barrier layer,
The maximum peak height of absorbance in the range of 1300 cm ⁻¹ to 1490 cm ⁻¹ is defined as α,
When the maximum peak height of absorbance in the range of 1690 cm ⁻¹ or more and 1780 cm ⁻¹ or less is γ,
The ratio of free carboxy groups to the _NH3 complex, represented by γ/α, is 0.00 or more and 1.00 or less,
(the number of moles of polyvalent metal derived from the polyvalent metal compound in the mixture)/(the number of moles of amino groups derived from the polyamine compound in the mixture) is 0.25 or more and 0.65 or less,
4. The gas barrier laminate according to claim 1, wherein (the number of moles of P atoms derived from the phosphorus compound or the salt thereof in the mixture)/(the number of moles of -COO- groups derived from the polycarboxylic acid in the mixture) is 0.001 or more and 0.3 or less. 5. The gas barrier laminate according to claim 1, wherein the gas barrier layer has a thickness of 0.01 μm or more and 15 μm or less. 6. The gas barrier laminate according to claim 1, wherein the polyvalent metal compound is a compound of one or more divalent or higher metals selected from the group consisting of Zn, Ca, Mg, Ba and Al. 7. The gas barrier laminate according to claim 1, wherein the phosphorus compound is one or more compounds selected from the group consisting of phosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, phosphonic acid, and salts thereof. 8. The gas barrier laminate according to claim 1, wherein the polycarboxylic acid comprises one or more polymers selected from the group consisting of polyacrylic acid, polymethacrylic acid, and a copolymer of acrylic acid and methacrylic acid. The gas barrier laminate according to claim 1 , wherein the polyamine compound comprises polyethyleneimine. 10. The gas barrier laminate according to claim 1, wherein the base layer comprises one or more resins selected from the group consisting of polyamide, polyethylene terephthalate, and polybutylene terephthalate.

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