JP7470628B2 - Gas barrier laminate - Google Patents

Description

The present invention relates to a gas barrier laminate.

Generally, a laminate in which an inorganic layer with gas barrier properties is provided on a substrate layer is used as a gas barrier material against water vapor or oxygen.

However, this inorganic layer is vulnerable to friction and other factors, and such gas barrier laminates can suffer cracks in the inorganic layer due to friction or stretching during post-processing such as printing, lamination, or filling, resulting in a decrease in gas barrier properties.

For example, Patent Document 1 (WO 2016/017544) discloses a gas barrier coating material that contains a polycarboxylic acid, a polyamine compound, a polyvalent metal compound, and a base, and has a ratio of (the number of moles of -COO- groups contained in the polycarboxylic acid)/(the number of moles of amino groups contained in the polyamine compound) of 100/20 to 100/90.

Patent Document 1 discloses that the use of such a gas barrier coating material makes it possible to provide a gas barrier film and a laminate thereof that have good gas barrier properties, particularly oxygen barrier properties, under both low and high humidity conditions.

Furthermore, Patent Document 2 (WO 03/091317) discloses a film made from a polycarboxylic acid (A) and a polyvalent metal compound (B), the film having an infrared absorption spectrum peak ratio ( _A1560 / _A1700 ) of 0.25 or more.

Patent Document 2 discloses that such a film has excellent gas barrier properties such as oxygen even in a high humidity atmosphere, and has water resistance such that the appearance, shape, and gas barrier properties are not impaired by the effects of neutral water, high-temperature water vapor, and hot water, and a film that is easily soluble in acid and/or alkali can be obtained.

Furthermore, Patent Document 3 (WO 2016/088534) discloses a gas barrier polymer formed by heating a mixture containing a polycarboxylic acid and a polyamine compound, in which, in an infrared absorption spectrum of the gas barrier polymer, 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 and 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 area ratio of amide bonds, represented by B/A, is 0.370 or more.

Patent Document 3 discloses that such a polymer can realize a gas barrier film and a gas barrier laminate that have excellent gas barrier performance under both high humidity conditions and after boiling and retorting treatment, while also having an excellent balance of appearance, dimensional stability, and productivity.

International Publication No. 2016/017544 WO 03/091317 International Publication No. 2016/088534

The technical level required for various properties of gas barrier materials is becoming increasingly higher. The inventors have found the following problems with conventional gas barrier materials such as those described in Patent Documents 1 to 3.

As described in Patent Documents 1 and 2, gas barrier materials made of a system containing polycarboxylic acid and a polyvalent metal compound have been found to have a problem in that the barrier performance of the two-layer laminate structure deteriorates after retort treatment.

In addition, it was found that gas barrier materials made of a system containing polycarboxylic acid and polyamine compounds, as described in Patent Document 3, have a three-layer laminate structure, and the barrier performance deteriorates after retort treatment.

As described above, the present inventors have found that the conventional gas barrier materials described in Patent Documents 1 to 3 have a laminate structure, and therefore have a problem in that the barrier performance deteriorates after retort treatment.
That is, the present inventors have found that there is room for improvement in conventional gas barrier materials in terms of barrier performance after retort treatment, regardless of the laminate structure.

The present invention has been made in consideration of the above circumstances, and provides a barrier laminate that can be used for a barrier film that has good barrier performance after retort treatment, regardless of the laminate structure.

The inventors of the present invention have conducted extensive research to achieve the above object. As a result, they have discovered that a gas barrier laminate having a gas barrier layer in which Zn is in a specific composition ratio range as determined by X-ray photoelectron spectroscopy (XPS) analysis and the intensity ratio of a specific peak derived from Zn as observed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis is in a certain range has good barrier performance after retort treatment, regardless of the laminate structure, and have completed the present invention.

That is, according to the present invention, there is provided the following gas barrier laminate.
1.
A gas barrier layer provided on at least one surface of the base layer, and an inorganic layer provided between the base layer and the gas barrier layer,
the gas barrier layer has a Zn composition ratio of 1 to 10 atomic %, as measured by X-ray photoelectron spectroscopy;
The gas barrier layer is subjected to time-of-flight secondary ion mass spectrometry, and the mass peak intensity of ⁶⁴ ZnPO ₄ H ^- is defined as I( ⁶⁴ ZnPO ₄ H ^- ) and the mass peak intensity of C ₃ H ₃ O ₂ ^- is defined as I(C ₃ H ₃ O ₂ ^- ).
^I ( ^64ZnPO4H _- ⁾ /I _{( C3H3O2- )}
The gas barrier laminate has a value of 7×10 ⁻⁴ or more and 5×10 ⁻² or less.
2.
The gas barrier layer is measured by time-of-flight secondary ion mass spectrometry, and when the mass peak intensity of PO ₂ ^- is I(PO ₂ ^- ) and the mass peak intensity of PO ₃ ^- is I(PO ₃ ^- ),
(I( _PO2- ⁾ + ^I ( _PO3- ⁾ ) / I _{( C3H3O2- )}
2. The gas barrier laminate according to 1., wherein the value of is 0.02 or more and 5 or less.
3.
The intensity ratio of I(PO ₂ ⁻ ) to I(PO ₃ ⁻ ), I(PO ₂ ⁻ )/I(PO ₃ ⁻ ),
3. The gas barrier laminate according to 1. or 2., wherein the value of is 0.05 or more and 1 or less.
4.
4. The gas barrier laminate according to any one of 1. to 3., wherein the gas barrier layer is constituted by a cured product of a mixture containing at least a polycarboxylic acid, Zn, and a phosphorus compound containing one or more -P-OH groups or a salt thereof.
5.
5. The gas barrier laminate according to 4., wherein the concentration of the phosphorus compound containing one or more -P-OH groups or its salt in the mixture is 5 x 10 ^-4 mol or more and 0.3 mol or less per mol of carboxyl groups in the polycarboxylic acid.
6.
6. The gas barrier laminate according to 4. or 5., 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.
7.
7. The gas barrier laminate according to any one of 1. to 6., wherein the gas barrier layer has a thickness of 0.05 μm or more and 10 μm or less.

The present invention provides a gas barrier laminate that has good barrier performance after retorting, regardless of the laminate structure.

FIG. 1 is a cross-sectional view showing a schematic example of a structure of a two-layer laminate gas barrier laminate. FIG. 1 is a cross-sectional view showing a schematic example of a structure of a three-layer laminate gas barrier laminate. FIG. 13 is a diagram (graph) for explaining a triangular function Y _j (m) used in mass spectrometry data analysis. FIG. 1 is a diagram (graph) showing an example of curve fitting of mass spectrometry data.

The present embodiment will be described below with reference to the drawings. The drawings are schematic diagrams and do not necessarily correspond to the actual dimensional ratios. Unless otherwise specified, "~" between numerical values in the text indicates from above to below.

In the description of groups (atomic groups) in this specification, when a notation does not specify whether the group is substituted or unsubstituted, the notation includes both groups having no substituents and groups having a substituent. For example, an "alkyl group" includes not only an alkyl group having no substituents (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).
In this specification, the term "(meth)acrylic" refers to a concept that includes both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate."

<Gas Barrier Laminate>
The gas barrier laminate according to this embodiment is
a base layer, a gas barrier layer provided on at least one surface of the base layer, and an inorganic layer provided between the base layer and the gas barrier layer,
the gas barrier layer has a Zn composition ratio of 1 to 10 atomic %, as measured by X-ray photoelectron spectroscopy;
The gas barrier layer is subjected to time-of-flight secondary ion mass spectrometry, and the mass peak intensity of ⁶⁴ ZnPO ₄ H ^— is defined as I( ⁶⁴ ZnPO ₄ H ^— ) and the mass peak intensity of C ₃ H ₃ O ₂ ^— is defined as I(C ₃ H ₃ O ₂ ^— ).
^I ( ^64ZnPO4H _- ⁾ /I _{( C3H3O2- )}
The gas barrier laminate has a value of 7×10 ⁻⁴ or more and 5×10 ⁻² or less.

The Zn composition ratio of 1 to 10 atomic % measured by X-ray photoelectron spectroscopy means that the gas barrier layer contains Zn at a certain concentration.
Furthermore, the detection of C ₃ H ₃ O ₂ ^- in the gas barrier layer by mass spectrometry means that the gas barrier layer contains polyacrylic acid or its derivatives/analogous compounds (polyacrylic acid, etc.). The value of I(C ₃ H ₃ O ₂ ^- ) is considered to be a value correlated with the amount (concentration) of carboxyl groups of the polycarboxylic acid contained in the gas barrier layer.
Since the gas barrier layer contains Zn at a certain concentration and since the gas barrier layer contains polycarboxylic acid having a carboxyl group, it is believed that the polycarboxylic acid in the gas barrier layer forms a crosslinked product with Zn, and that the gas barrier layer forming the Zn crosslinked product, together with the inorganic layer provided between the base layer and the gas barrier layer, is responsible for the gas barrier properties of the gas barrier laminate.

Furthermore, the detection ^{of 64ZnPO4H-} from the gas barrier layer by mass spectrometry means that bonds between Zn and a phosphorus compound, typically _phosphoric acid, are present in the gas barrier layer, and the value of I( _64ZnPO4H- ⁾ is considered to be a value correlated with the amount (concentration) ^of bonds between the phosphorus compound and Zn. From this, it is inferred that Zn is not only bonded to the carboxyl group of polycarboxylic acid, but also that some Zn is chemically bonded to each other via the polyvalent phosphorus compound.
The value of I( ⁶⁴ ZnPO ₄ H ⁻ )/I(C ₃ H ₃ O ₂ ⁻ ) is considered to be a value correlated with the amount (concentration) of bonds between phosphoric acid and Zn relative to the carboxyl group of polycarboxylic acid.
Meanwhile, zinc phosphate is known as a compound insoluble in water, and the bond between the phosphorus compound and Zn is a bond that is difficult to break by water, which is one of the causes of the deterioration of the barrier property after retort treatment. Therefore, the presence of the bond between the phosphorus compound and Zn in the gas barrier layer is considered to suppress a significant deterioration of the gas barrier property due to excessive swelling/shrinkage of the gas barrier layer during retort treatment or the like, which would cause damage to the adjacent inorganic layer.
That is, by having a Zn composition ratio of 1 to 10 atomic % and a value of I( ⁶⁴ ZnPO ₄ H ⁻ )/I(C ₃ H ₃ O ₂ ⁻ ) of 7×10 ⁻⁴ or more and 5×10 ⁻² or less, the barrier performance after retort can be maintained at a good level.

Figure 1 shows a schematic cross-sectional view of an example of a two-layer laminate structure barrier film including a gas barrier laminate according to this embodiment. The two-layer laminate structure barrier film 1 includes a gas barrier laminate 8. The gas barrier laminate 8 includes a base layer 2, a gas barrier layer 5 on at least one side of the base layer 2, and an inorganic layer 4 between the base layer 2 and the gas barrier layer 5. An undercoat layer (UC layer) 3 may also be provided below the inorganic layer 4, i.e., on the base layer 2. In the two-layer laminate structure barrier film 1, for example, the gas barrier laminate 8 can be bonded to unoriented polypropylene (CPP) 7 via an adhesive layer 6.

Figure 2 shows a schematic cross-sectional view of an example of a three-layer laminate structure barrier film including the gas barrier laminate according to this embodiment. In the three-layer laminate structure barrier film 10, for example, a nylon film 9 is adhered onto the first adhesive layer 61 of a barrier laminate 8 having a first adhesive layer 61 provided thereon, and this nylon film 9 and unstretched polypropylene 7 can be adhered via a second adhesive layer 62.

The gas barrier layer 5 of the gas barrier laminate 8 according to this embodiment is a layer in which at least zinc (Zn) is detected by X-ray photoelectron spectroscopy (XPS) analysis, and a ⁶⁴ ZnPO ₄ H ^— peak and a C ₃ H ₃ O ₂ ^— peak are detected by time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis.
In the gas barrier layer of the gas barrier laminate according to this embodiment, a peak of ⁶⁴ ZnPO ₄ H ^— having high water resistance is detected, and thus the gas barrier laminate has good barrier performance after retort regardless of the laminate structure.

[XPS analysis]
The composition of Zn contained in the gas barrier layer is 1 atomic% or more, preferably 2 atomic% or more, more preferably 3 atomic% or more, as determined by XPS analysis. The composition of Zn contained in the gas barrier layer is 10 atomic% or less, preferably 9.5 atomic% or less, more preferably 9 atomic% or less. This corresponds to the peak intensity of Zn relative to the peak intensity of carbon, i.e., Zn/C, being 0.01 to 0.2 (atomic/atomic%).
In this way, the presence of a certain amount of Zn in the gas barrier layer improves the barrier performance after retort.

An example of specific conditions for the XPS analysis applicable to this embodiment is shown below.
Analytical device: AXIS-NOVA manufactured by KRATOS
X-ray source: monochromated Al-Kα
X-ray source power: 15 kV, 10 mA
Analysis area: 300 x 700 μm
During analysis: A neutralizing gun for charge correction is used. In the XPS analysis, a 1 x 1 cm measurement sample cut out from the gas barrier layer can be used. In addition, in order to analyze the inside of the gas barrier layer, it is preferable to sputter etch the surface of the gas barrier layer before the analysis. For sputter etching, it is preferable to use an Ar-gas cluster ion beam (Ar-GCIB) source in order to reduce damage to the gas barrier layer. Ar-gas cluster ion beam etching is known as a technique that allows etching without destroying the chemical structure of the specimen.

In XPS analysis, the detected elements are identified by wide scanning, and the spectrum of each element is obtained by narrow scanning. The background is estimated from the obtained spectrum by the Shirley method, and the background is removed from the spectrum. A spectrum from which the background has been removed is obtained for each measured element, and the atomic composition ratio (atomic %) of the detected element is calculated from the obtained peak area using the relative sensitivity factor method.
In addition, the detection sensitivity of the atomic composition ratio in a general XPS analysis is about 0.1 atomic %. For example, when a trace amount of a phosphorus compound is added to the gas barrier layer, the content of P may not be detected by the XPS analysis.

[TOF-SIMS analysis]
Among the fragments detected in the TOF-SIMS analysis of the gas barrier layer, the peak intensity of ⁶⁴ ZnPO ₄ H ^— is defined as I( ⁶⁴ ZnPO ₄ H ^— ) and the peak intensity of the C ₃ H ₃ O ₂ ^— fragment is defined as I(C ₃ H ₃ O ₂ ^— ),
^I ( ^64ZnPO4H _- ⁾ /I _{( C3H3O2- )}
is 7×10 ⁻⁴ or more, preferably 1×10 ⁻³ or more, and more preferably 2×10 ⁻³ or more. Also, it is 5×10 ⁻² or less, preferably 3×10 ⁻² or less, and more preferably 2×10 ⁻² or less.
In this way, _when the mass peak ^{of 64ZnPO4H-} _, which is a _fragment derived from a highly water-resistant bond _, is detected and the value of I( ^{64ZnPO4H -} )/I( _C3H3O2- ⁾ is within the above range, the gas barrier laminate has good barrier performance after retort regardless of the laminate structure. Also, if the value of I( ^{64ZnPO4H -} ₎ /I( _C3H3O2- ⁾ is too large, fine particles of zinc _phosphate bonds grow in the gas barrier layer, which causes non-uniformity in the gas barrier layer _and tends to deteriorate the gas barrier performance.

An example of specific conditions for the TOF-SIMS analysis applicable to this embodiment is shown below.
In order to analyze the inside of the gas barrier layer, it is preferable to perform sputter etching of the surface layer of the gas barrier layer using an Ar-gas cluster ion beam (Ar-GCIB) attached to a TOF-SIMS analyzer prior to TOF-SIMS analysis. The use of Ar-GCIB can reduce damage to the gas barrier layer.
An example of specific conditions for Ar-GCIB that can be applied to this embodiment is shown below.
GCIB: 5 kV, 5 μA
GCIB processing time: the point at which the TOF-SIMS spectrum pattern no longer changes

The TOF-SIMS analysis can be carried out, for example, as follows.
Analytical equipment: PHI nano-TOFII manufactured by ULVAC-PHI
Primary ion: _Bi32 ⁺
Primary ion source output: 30 kV, 0.5 μA
Analysis area: 300×300 μm (scanning area of primary ion beam)
During the analysis, charge neutralization can be performed by irradiating a low-energy electron beam and low-energy Ar ions attached to the device. In addition, in the TOF-SIMS analysis, a measurement sample of 1 × 1 cm cut out from the gas barrier layer can be used, as in the XPS analysis.

In this case, when the mass peak intensity of PO ₂ ^- observed by TOF-SIMS analysis of the gas barrier layer is defined as I(PO ₂ ^- ) and the mass peak intensity of PO ₃ ^- observed by TOF-SIMS analysis of the gas barrier layer is defined as I(PO ₃ ^- ),
I( _PO2 ^- )+I( _PO3 ^- )/ _{I ( C3H3O2-} ⁾
The value of I(PO ₂ ⁻ )+I(PO ₃ ⁻ )/I(C ₃ H ₃ O ₂ ⁻ ) is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less.
The detection of a PO ₂ ^- or PO ₃ ^- mass peak means that the gas barrier layer contains a phosphorus compound containing one or more P-OH groups, such as phosphoric acid. The value of I(PO ₂ ^- ) + I(PO ₃ ^- )/I(C ₃ H ₃ O ₂ ^- ) is considered to be a value correlated with the amount (concentration) of the phosphorus compound relative to the carboxyl groups of the polycarboxylic acid in the gas barrier layer.

At this time, the intensity ratio of I(PO ₂ ⁻ ) to I(PO ₃ ⁻ ), I(PO ₂ ⁻ )/I(PO ₃ ⁻ ),
The value of I(PO _{2 − )/I(PO 3 − ) is preferably 0.05 or more, more preferably 0.08 or more, and even more preferably 0.1. The value of I(PO 2} ⁻ _{)/I(PO 3} ⁻ ) is 1 or less, preferably 0.9 or less, and more preferably 0.8 or less.
In TOF-SIMS analysis, the detection of mass peaks of PO ₂ ^- and PO ₃ ^- means that phosphorus compounds such as phosphoric acid (H ₃ PO ₄ ) are present, and the ratio I(PO ₂ ^- )/I(PO ₃ ^- ) is a value reflecting the type of phosphorus compound containing a P-OH group.
I( ^64ZnPO4H -)/I _{( C3H3O2-} ) _, which reflects the amount ( _{concentration} ) of zinc phosphate bonds, affects the type of phosphorus compound ^. In other words, it is also related to the value of I( _PO2 ^- )/I( _PO3- ). The value of I( _PO2 ^- )/I ₍ ^{PO3- )} being 0.05 or more and 1 or less means that the value of I( ^{64ZnPO4H -} )/I( _C3H3O2- ) is in _an appropriate range, and _the barrier performance of the gas barrier laminate of this embodiment after retort can be maintained at _a good level.

The data obtained by TOF-SIMS analysis can be analyzed as follows.
In order to perform detailed spectrum analysis, in this embodiment, for each positive and negative secondary ion, a raw data sequence in which mass numbers m _i and corresponding count numbers c _i are paired, and total ion counts (C _T ) are acquired by the analyzer, where i=0, 1, 2, ..., N, and the raw data sequence is arranged in ascending order with respect to m _i . Note that C _T is the total count number of secondary ions detected by the detector.

The range of mass numbers around a mass spectrum peak of interest is defined as i = _n1 , _n1 + 1, ..., _n2 . The count data c _i in this range obtained by analysis is approximated by y _i as shown in the following formula. Specifically, c _i is approximated by curve fitting using the background level b ⁰ and K triangular functions Y _j (m _i ), where b ⁰ is a constant.

Y _j (m _i ) is a function having a peak value Y ⁰ _j at mass number x ⁰ _j as shown in FIG.

Here, b ⁰ , x ⁰ _j , Y ⁰ _j , B ⁻ _j , and B ⁺ _j are fitting parameters. In addition, j is j=1, ..., K. For example, when the background of the spectrum is not a constant value but changes linearly with respect to m _i , b ⁰ and a triangular function Y _j (m _i ) are combined to approximate the background. When the mass spectrum peak of interest is a single peak, it is approximated by one triangular function excluding the background, and when it is close to other mass peaks, it is approximated by using multiple triangular functions including the other mass peaks. If the approximated mass spectrum peak of interest is the j=kth peak among K triangular functions, the peak intensity I is expressed as a numerical value normalized by Total Ion Counts (C _T ) for the sum of Y _k (m _i ) up to i=n ₁ , ..., n ₂ , and is obtained from the following formula.

If a mass spectrum peak has a tail, it becomes difficult to define the range of mass numbers to be counted. In this embodiment, to avoid this, the mass spectrum peak is approximated by a triangular function. This means that the counts in the tail of the mass spectrum peak are ignored. Curve fitting is performed so that the central part of the mass spectrum peak fits the triangular function.
In addition, other components (e.g., different mass peaks with the same mass number) that overlap with the target peak component may be observed. In such cases, the target peak component is found by approximating the other components that overlap with the target peak component using a triangular function.
The mass numbers of the fragments of interest in this embodiment are calculated and shown below. The atomic weights of the isotopes are based on http://physics.nist.gov/.

[Calculation of mass peak intensity _of ^{64ZnPO4H- ]}
Five isotopes of Zn are known, and in TOF-SIMS analysis, fragments related to ^64Zn , ^66Zn , and ^68Zn are mainly detected. In this embodiment, attention is focused on ^64Zn _, which has the highest abundance ratio. Fragments indicating bonds between ^64Zn and phosphorus compounds containing _P -OH include ^{64ZnPO4H- , 64ZnP2O6H- ,} _64ZnP2O7H- ^, _{and 64ZnP3O9H- ,} ^{but attention} is focused ^{on 64ZnPO4H-} _{, which} has ^a relatively large _mass peak intensity.
Focusing on the range of mass numbers from ^159.5 to 160.3 in the negative secondary ion spectrum, the sum of the counts is calculated from the data of _m and ^a triangular function approximating the mass peak near _158.890 corresponding to ^{64Zn31P16O41H- ,} and the value normalized by _{CT is} taken as ^the _mass peak ^intensity I( ^{64ZnPO4H- )} of ^64ZnPO4H- .

An example of curve fitting is shown in Figure 4, and the parameters used and the calculation results of the total count number are shown in Table 2. In the example shown in Figure 4, the total count number obtained from the triangular function approximating the mass peak of the target ⁶⁴ ZnPO ₄ H ^- and the data of m _i is 1514. Since the total ion counts (C _T ) of the negative secondary ions at this time is 8571746, the peak intensity I( ⁶⁴ ZnPO ₄ H ^- ) of ⁶⁴ ZnPO ₄ H ^- is
I( ^64ZnPO4H _- ⁾ =1514/8571746=1.77× ^10-4
It becomes.

A supplementary explanation will be given with respect to FIG. 4, which shows an example of curve fitting.
(i) To obtain an approximation curve _yi that reproduces the measurement data _ci in the vicinity of the target peak position, the curves of the "background ^b0 " and the "triangular function approximation of other components" and the curve of the "target triangular function _Yj ( _mi )" are required.
(ii) In the example of FIG. 4, in order to obtain an “approximation curve y _i ” that reproduces the measurement data c _i in the mass number (m/z) range of 159.7 to 160.2, the “background b ⁰ ”, the curve of the “target triangular function Y _j (m _i )” (j=2 in Table 2), and two curves of the “triangular function approximation of other components” (j=0, 1 in Table 2) were used.

[Calculation of mass peak intensity of C ₃ H ₃ O ₂ ^- ]
Focusing on the range of mass numbers from 70.7 to 71.4 in the negative secondary ion spectrum, the sum of the counts is calculated from the triangular function Y _k (m _i ) that approximates the mass peak near 71.013 corresponding to ¹² C ₃ ¹ H ₃ ¹⁶ O ₂ ^- obtained by curve fitting and the data for m _i , and the value normalized by C _T is taken as the mass peak intensity I(C ₃ H ₃ O ₂ ^- ) of C ₃ H ₃ O ₂ ^- .

[Calculation of PO ₂ ^- mass peak intensity]
Focusing on the range of mass numbers from 62.5 ^{to 63.3 in the negative secondary ion spectrum, the sum of the counts is calculated from a triangular function approximating the mass peak near 62.964 corresponding to 31P16O2-} _and ^{the data} of m _i , and the value normalized by _CT is taken as the mass peak intensity I( _PO2- ^{) of} _PO2- .

[Calculation of PO ₃ ^- mass peak intensity]
Focusing on the range of mass numbers from 78.5 ^to 79.3 in the negative secondary ion spectrum, the sum of the counts is calculated from a triangular function approximating the mass peak near _78.959 corresponding ^{to 31P16O3-} and the data of m _i , and the value normalized by _CT is taken as the mass peak intensity I( _PO3- ^{) of} _PO3- .

The gas barrier layer is preferably formed from a cured mixture containing polycarboxylic acid, Zn, and a phosphorus compound or a salt thereof containing one or more P-OH groups, such as phosphoric acid (H ₃ PO ₄ ).
In the case of a gas barrier layer formed from a cured product of a mixture containing these components, the carboxyl groups derived from polycarboxylic acid form metal ion bridges via Zn, and Zn also reacts with phosphorus compounds containing P-OH groups to form water-resistant bonds. Although the detailed mechanism is unclear, it is believed that the presence of these metal ion bridges via Zn and bonds between Zn and phosphorus compounds uniformly and in appropriate amounts in the gas barrier layer forms a dense gas barrier layer and inhibits the gas barrier layer from excessively swelling or shrinking during retort treatment or the like.

The Zn composition ratio of _the gas barrier layer according to this embodiment and the values of I( ^{64ZnPO4H -} _{)/I(C3H3O2-), I(PO2-)+I(PO3 - )} ^/ _I ⁽ _C3H3O2- ⁾ _and I( _PO2 ^- )/I( _PO3- ⁾ in _{TOF -} SIMS can be controlled by appropriately adjusting the manufacturing conditions of the gas barrier layer ^.
In this embodiment, for example, the concentration of phosphoric acid relative to polycarboxylic acid is one of the factors for controlling the Zn composition ratio and the value of I( ⁶⁴ ZnPO ₄ H ⁻ )/I(C ₃ H ₃ O ₂ ⁻ ).

The polycarboxylic acid, zinc or its compound, phosphorus compound, and other components that can be added and are applicable to this embodiment are described in detail below.

(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 acrylic acid, methacrylic 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 and methacrylic acid or copolymers thereof are preferred, and one or more polymers selected from 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 particularly preferred.

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

In this embodiment, polymethacrylic acid includes both a homopolymer of methacrylic acid and a copolymer of methacrylic acid and other monomers. In the case of a copolymer of methacrylic acid and other monomers, the polymethacrylic acid contains structural units derived from methacrylic acid in an amount of usually 90% by mass or more, preferably 95% by mass or more, and more preferably 99% by mass or more, per 100% by mass of the polymer.

Polycarboxylic acids are polymers formed by polymerization of carboxylic acid monomers, and 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, from the viewpoint of excellent balance between gas barrier properties and ease of handling.

Here, the molecular weight of the polycarboxylic acid is the weight average molecular weight calculated as polyethylene oxide, and can be measured using gel permeation chromatography (GPC).

Neutralizing the polycarboxylic acid with a volatile base can prevent gelation from occurring when zinc and polycarboxylic acid are mixed, as described below. Therefore, in the polycarboxylic acid, it is preferable to partially or completely neutralize the carboxyl groups with a volatile base from the viewpoint of preventing gelation. The neutralized product can be obtained by partially or completely neutralizing the carboxyl groups of the polycarboxylic acid with a volatile base (i.e., partially or completely converting the carboxyl groups of the polycarboxylic acid into carboxylates). This can prevent gelation when zinc is added.

The partially neutralized product is 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 30 to 100 equivalent percent, and more preferably 50 to 100 equivalent percent.

Any water-soluble base can be used as the volatile base.

Examples of volatile bases include ammonia, morpholine, alkylamines, tertiary amines such as 2-dimethylaminoethanol, N-methylmonopholine, ethylenediamine, and triethylamine, or aqueous solutions of these, or mixtures of these. From the viewpoint of obtaining good gas barrier properties, an aqueous ammonia solution is preferred.

The mixture constituting the gas barrier laminate according to this embodiment preferably further contains an ammonium carbonate salt. The ammonium carbonate salt is added to convert zinc, which will be described later, into a zinc ammonium carbonate complex, thereby improving the solubility of zinc and preparing a homogeneous solution containing zinc.

Examples of carbonate-based ammonium salts include ammonium carbonate and ammonium hydrogen carbonate. Ammonium carbonate is preferred because it is easily volatilized and is unlikely to remain in the resulting gas barrier layer.

(zinc)
Zinc (Zn) can form a water-resistant phosphate-Zn bond with a phosphorus compound, and a mass peak represented by ⁶⁴ ZnPO ₄ H ^- can be detected by TOF-SIMS analysis. When the gas barrier layer contains a polycarboxylic acid, it forms a salt with the polycarboxylic acid. Zn may be any zinc or zinc compound that can be added to the mixture that forms the gas barrier layer, and examples of the zinc that can be used include metallic zinc, zinc oxide (ZnO), and zinc compounds. The amount of zinc added can be 0.1 mol or more and 0.5 mol or less per mol of carboxyl groups of the polycarboxylic acid.

(Phosphorus compounds)
As described above, when the gas barrier layer is subjected to mass spectrometry, PO ₂ ^- and/or PO ₃ ^- are preferably detected. In order to provide such a gas barrier layer, the mixture before curing preferably contains a phosphorus compound or a salt thereof.
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. From the viewpoint of productivity, the number of -P-OH groups in the phosphorus compound may be, for example, 10 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-mentioned phosphorus compounds, such as phosphorylated starch and phosphate-crosslinked starch; halides, such as chlorides; anhydrides, such as tetraphosphoric acid 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 the barrier property 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, phosphorous acid, phosphonic acid, and salts thereof.
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 barrier properties, the salt of the phosphorus compound is preferably an ammonium salt.
The concentration of P atoms in the phosphorus compound is typically 5× ^{10 mol or more, preferably 1×10} mol or more, more preferably 5×10 mol or more, and typically ^0.3 mol or less, preferably ^0.15 mol or less, more preferably 0.1 mol or less, per 1 mol of carboxyl groups in the polycarboxylic acid in the compound. In phosphorus compounds containing one P atom in the 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.
It is believed that a phosphorus compound derived from such a concentration or its salt can reliably form Zn bonds with the water-resistant phosphorus compound, thereby suppressing excessive swelling and shrinkage of the gas barrier layer during retort treatment, etc., and further improving the gas barrier property of the gas barrier laminate after retort treatment. The presence of the phosphorus compound and Zn bonds is reflected in the mass peak of ⁶⁴ ZnPO ₄ H ^- obtained by the above-mentioned TOF-SIMS analysis.

(Other ingredients)
The mixture constituting the gas barrier layer according to the present embodiment may or may not contain, for example, a polyamine as an additional component. When the mixture contains a polyamine, the barrier properties of the resulting gas barrier laminate can be improved, and the interlayer adhesion of the resulting gas barrier laminate can be improved, resulting in good delamination resistance.
In addition, since the fragments detected in the TOF-SIMS analysis are detected independently, the values of I( ⁶⁴ ZnPO ₄ H ⁻ )/I(C ₃ H ₃ O ₂ ⁻ ), (I(PO ₂ ⁻ )+I(PO ₃ ⁻ ))/I(C ₃ H ₃ O ₂ ⁻ ), and I(PO ₂ ⁻ )/I(PO ₃ ⁻ ) obtained by analyzing the results of the TOF-SIMS analysis are not affected by the presence or absence of polyamine.

A polyamine is a polymer having two or more amino groups in the main chain, side chain, or terminal. 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. Polyamines in which some of the amino groups have been modified may also be used. The amount of polyamine added can be an amount such that the amount of active hydrogen in the polyamine is 0 mol to 0.9 mol per 1 mol of carboxyl groups contained in the polycarboxylic acid.

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

<Method of manufacturing gas barrier layer>
The gas barrier layer according to this embodiment can be produced, for example, as follows.
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 the 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 that occurs in the subsequent process when zinc is added and reacts with the carboxyl groups that make up the polycarboxylic acid, resulting in a uniform intermediate gas barrier coating material.

Next, a zinc salt compound and a carbonate-based ammonium salt are added to the intermediate and dissolved, and the resulting zinc ions form a zinc salt with the -COO- groups that constitute the polycarboxylic acid. The -COO- groups that form salts with the zinc ions refer to both carboxy groups that have not been neutralized with the base and -COO- groups that have been neutralized with a base. In the case of -COO- groups that have been neutralized with a base, the zinc ions derived from the zinc mentioned above are coordinated in a swap to form a zinc salt of the -COO- group. After the zinc salt is formed, phosphoric acid is added to obtain a gas barrier coating material (mixture).

The gas barrier coating material (mixture) thus produced is applied to the inorganic layer described below, and dried and cured to form a gas barrier layer. The method for applying the gas barrier coating material to the substrate layer is not particularly limited, and a conventional method can be used. For example, coating can be performed using various known coating machines such as a Mayer bar coater, an air knife coater, a direct gravure coater, a gravure offset coater, an arc gravure coater, a gravure reverse coater, a jet nozzle type gravure coater, a top feed reverse coater, a bottom feed reverse coater, a nozzle feed reverse coater, a five roll coater, a lip coater, a bar coater, a bar reverse coater, a die coater, etc.

The coating amount (wet thickness) of the gas barrier coating material (mixture) is preferably 0.05 μm or more, more preferably 1 μm or more. The coating amount is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less.
The average thickness of the gas barrier layer after drying and curing is preferably 0.05 μm to 10 μm, more preferably 0.08 μm to 5 μm, and even more preferably 0.1 μm to 1 μm. When it is equal to or less than the upper limit, curling of the resulting gas barrier laminate or gas barrier film can be suppressed. When it is equal to or more than the lower limit, the barrier performance of the resulting gas barrier laminate or gas barrier film can be improved.

The drying and heat treatment can be carried out after drying, or simultaneously.

The method of drying and heating is not particularly limited as long as it can achieve the object of the present invention, but it 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 using ovens, dryers, etc., conductive heat transfer using heated rolls, etc., radiation heat transfer using electromagnetic waves such as infrared, far-infrared, and near-infrared heaters, and internal heat generation using microwaves, etc. are included. From the viewpoint of manufacturing efficiency, the device used for drying and heating is preferably a device capable of both drying and heating. Among them, specifically, it is preferable to use a hot air oven from the viewpoint of being usable for various purposes such as drying, heating, and annealing, and it is also preferable to use a heated roll from the viewpoint of excellent thermal conductivity to the film. In addition, the methods used for drying and heating may be appropriately combined. A hot air oven and a heated roll may be used in combination. For example, if the gas barrier coating material is dried in a hot air oven and then heated with a heated roll, the heating process will be short, which is preferable from the viewpoint of manufacturing efficiency. It is also preferable to perform drying and heating only with a hot air oven.

For example, it is desirable to carry out the heat treatment at a heat treatment temperature of 80 to 250°C and a heat treatment time of 1 second to 10 minutes, preferably at a heat treatment temperature of 120 to 240°C and a heat treatment time of 1 second to 1 minute, and more preferably at a heat treatment temperature of 170°C to 230°C and a heat treatment time of 1 second to 30 seconds. Furthermore, as mentioned above, the use of a heating roll in combination makes it possible to carry out the heat treatment in a short time. It is important to adjust the heat treatment temperature and heat treatment time according to the wet thickness of the gas barrier coating material.

In the gas barrier coating material (mixture), the zinc salt of the -COO- group that constitutes the polycarboxylic acid forms a water-resistant Zn phosphate bond with the metal bridge (reflected in the mass peak of ⁶⁴ ZnPO ₄ H ^- obtained in the TOF-SIMS analysis described above), and by drying and heat-treating, a gas barrier layer with excellent gas barrier properties is obtained.

(Inorganic Layer)
Examples of inorganic materials constituting the inorganic layer 4 include metals, metal oxides, metal nitrides, metal fluorides, and metal oxynitrides that can form thin films having barrier properties.

Examples of inorganic substances constituting the inorganic layer 4 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 names of elements in the periodic table are shown in the old CAS format.

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 is formed from the above-mentioned inorganic material. The inorganic layer 4 may be composed of a single inorganic layer, or may be composed of multiple inorganic layers. Furthermore, when the inorganic layer 4 is composed of multiple inorganic layers, the inorganic layers may be the same type, or different types.

From the viewpoint of a balance between barrier properties, adhesion, ease of handling, and the like, the thickness of the inorganic layer 4 is usually from 1 nm to 1000 nm, and preferably from 1 nm to 500 nm.
In this embodiment, the thickness of the inorganic layer can be determined from an image observed with a transmission electron microscope or a scanning electron microscope.

The method for forming the inorganic layer is not particularly limited, and for example, the inorganic layer 4 can be formed on one or both sides of the base layer 2 by vacuum deposition, ion plating, sputtering, chemical vapor deposition, physical vapor deposition, chemical vapor deposition (CVD), plasma CVD, sol-gel method, 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 this will improve the surface smoothness of the inorganic layer 4 and reduce the number of holes by quickly reacting with chemically active molecular species containing silicon, such as silicon nitride and silicon oxynitride.
In order to carry out these bonding reactions quickly, it is desirable that the inorganic atoms or compounds are chemically active molecular or atomic species.

(Base layer)
The substrate layer 2 is not particularly limited and can be used as long as it can be coated with a solution of a gas barrier coating material. For example, organic materials such as thermosetting resins, thermoplastic resins, or paper, inorganic materials such as glass, pottery, ceramics, silicon oxide, silicon oxynitride, silicon nitride, cement, aluminum, aluminum oxide, metals such as iron, copper, and stainless steel, and multi-layered substrate layers made of organic materials or combinations of organic materials and inorganic materials are listed. Among these, for example, in the case of various film applications such as packaging materials and panels, organic materials such as plastic films using thermosetting resins and thermoplastic resins, or 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, polymetaxylene 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, polyethylene naphthalate, polyamide, polyimide and polybutylene terephthalate are preferred, and 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.
The base layer 2 made of a thermoplastic resin may be a single layer or two or more layers depending on the application of the gas barrier laminate 8 .
Furthermore, a film formed from the above-mentioned thermosetting resin or thermoplastic resin may be stretched at least in one direction, preferably in two axial directions, to form a substrate layer.

From the viewpoint of excellent transparency, rigidity, and heat resistance, the base layer 2 according to this embodiment is preferably a biaxially stretched film formed from one or more thermoplastic resins selected from 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 polyamide, polyethylene terephthalate, and polybutylene terephthalate.

The surface of the base layer 2 may also be coated with polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, acrylic resin, urethane resin, etc.

Furthermore, the substrate layer 2 may be subjected to a surface treatment to improve adhesion. Specifically, surface activation treatments such as corona treatment, flame treatment, plasma treatment, and primer coating treatment may be performed.

From the viewpoint of obtaining good film characteristics, the thickness of the substrate layer 2 is preferably 1 to 1000 μm, more preferably 1 to 500 μm, and even more preferably 1 to 300 μm.

The shape of the substrate layer 2 is not particularly limited, but examples include a sheet or film shape, a tray, a cup, a hollow body, etc.

(Undercoat Layer)
In the gas barrier laminate 8, from the viewpoint of improving the adhesion between the base layer 2 and the inorganic layer 4, an undercoat layer 3 can be formed on the surface of the base layer 2. The undercoat layer is preferably a layer formed from an epoxy (meth)acrylate compound or a urethane (meth)acrylate compound.

The undercoat layer 3 is preferably a layer formed by curing at least one compound selected from an epoxy (meth)acrylate compound and a urethane (meth)acrylate compound.

Examples of epoxy (meth)acrylate compounds include compounds obtained by reacting epoxy compounds such as bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, phenol novolac type epoxy compounds, cresol novolac type epoxy compounds, and aliphatic epoxy compounds with acrylic acid or methacrylic acid, and also acid-modified epoxy (meth)acrylates obtained by reacting the above epoxy compounds with carboxylic acids or their anhydrides. These epoxy (meth)acrylate compounds are applied to the surface of the base layer together with a photopolymerization initiator and, if necessary, a diluent consisting of other photopolymerization initiators or heat-reactive monomers, and then irradiated with ultraviolet light or the like to form an undercoat layer by a crosslinking reaction.

Examples of urethane (meth)acrylate compounds include acrylated oligomers consisting of polyol compounds and polyisocyanate compounds (hereinafter also referred to as polyurethane oligomers).

Polyurethane oligomers can be obtained from the condensation product of a polyisocyanate compound and a polyol compound. Specific examples of polyisocyanate compounds include methylene bis(p-phenylene diisocyanate), an adduct of hexamethylene diisocyanate and hexanetriol, hexamethylene diisocyanate, tolylene diisocyanate, an adduct of tolylene diisocyanate and trimethylolpropane, 1,5-naphthylene diisocyanate, thiopropyl diisocyanate, ethylbenzene-2,4-diisocyanate, 2,4-tolylene diisocyanate dimer, hydrogenated xylylene diisocyanate, and tris(4-phenylisocyanate)thiophosphate. Specific examples of polyol compounds include polyether polyols such as polyoxytetramethylene glycol, polyester polyols such as polyadipate polyols and polycarbonate polyols, and copolymers of acrylic esters and hydroxyethyl methacrylate. Examples of monomers constituting acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, and phenyl (meth)acrylate.

These epoxy (meth)acrylate compounds and urethane (meth)acrylate compounds are used in combination as necessary. Methods for polymerizing these compounds include various known methods, specifically, methods involving irradiation with energy rays including ionizing radiation or heating.

When the undercoat layer is formed by curing with ultraviolet light, it is preferable to use a mixture of acetophenones, benzophenones, myfilabenzoyl benzoate, α-amyloxime ester, thioxanthones, etc. as a photopolymerization initiator, and n-butylamine, triethylamine, tri-n-butylphosphine, etc. as a photosensitizer. In this embodiment, epoxy (meth)acrylate compounds and urethane (meth)acrylate compounds are also used in combination.

These epoxy (meth)acrylate compounds and urethane (meth)acrylate compounds are diluted with (meth)acrylic monomers. Examples of such (meth)acrylic monomers include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, and phenyl (meth)acrylate, and examples of polyfunctional monomers include trimethylolpropane tri(meth)acrylate, hexanediol (meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate.

In particular, when a urethane (meth)acrylate compound is used for the undercoat layer, the oxygen gas barrier properties of the resulting gas barrier laminate 8 are further improved.
The thickness of the undercoat layer in this embodiment is usually in the range of 0.01 to 100 g/m ² , preferably 0.05 to 50 g/m ² , in terms of the coating amount.

(Adhesive Layer)
An adhesive layer 6 may be provided on the gas barrier layer 5. The adhesive layer 6 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., one-component or two-component 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.

In addition, 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 8. If the gas barrier laminate is to be used in 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.

The gas barrier laminate 8 according to this embodiment has excellent gas barrier performance after retort regardless of the laminate structure. Therefore, it is preferably used as a packaging material, particularly as a food packaging material for contents that require high gas barrier properties. It can also be used as a packaging material for various medical, industrial, and everyday goods applications.

The gas barrier laminate 8 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.

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 A polyacrylic acid (PPA) 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 PPA concentration of 10%. Ammonia water with a concentration of 10% was added to this aqueous solution so that the amount of ammonia was 1.5 mol per mol of carboxyl groups in the PPA, and an aqueous solution of ammonium polyacrylate with a PPA concentration of 7.38% was obtained.
Next, zinc oxide (ZnO) (Kanto Chemical) and ammonium carbonate (Kanto Chemical) were added to the obtained aqueous solution of ammonium polyacrylate, and mixed and stirred to obtain a mixed solution. The amount of zinc oxide added was such that the molar ratio of (zinc oxide)/(carboxyl group of polyacrylic acid) was 0.3. The amount of ammonium carbonate added was such that the molar ratio of the carboxyl group of polyacrylic acid was 0.3.
In addition, purified water was added to the above mixture so that the solid content concentration of PPA+ZnO was 2%, and the mixture was stirred until it became a uniform solution. In addition, ammonium hydrogen phosphate ((NH ₄ ) ₂ HPO 4 ) (manufactured by Kanto Chemical Co., Ltd.) was added and stirred in an aqueous solution of ammonium hydrogen phosphate with a solid content concentration of 2% so that the amount of ammonium hydrogen phosphate ((NH 4 ) 2 HPO ₄ ) (manufactured by Kanto Chemical Co., Ltd.) was 0.01 mol per 1 mol of carboxyl group of PPA. After that, an aqueous solution of activator (manufactured by Kao Corporation, product name: Emulgen 120) with a solid content concentration of 1% was mixed in such a way that the amount of activator was 0.3 mass% per mol of the solid content of PPA+ZnO, to prepare a coating material for gas barrier.

(2) Preparation of a gas barrier laminate A transparent deposition film (Mitsui Chemicals Tohcello Co., Ltd., model number: TL-PET-H) was prepared by depositing aluminum oxide as an inorganic layer on a 12 μm PET film as a base layer. This film was attached to a glass plate with the inorganic deposition layer facing up, and a gas barrier coating material was applied with an applicator so that the film thickness after drying was 0.2 μm. Then, 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 heat treatment was performed in a hot air dryer at 150° C. for 1 minute. As a result, a gas barrier laminate in which a gas barrier layer was formed on a transparent deposition film was prepared.
Table 3 shows the preparation conditions.

(3) Analysis of Gas Barrier Layer The gas barrier layer of the gas barrier laminate obtained in (2) above was subjected to XPS analysis and TOF-SIMS analysis.

XPS analysis conditions Analysis equipment: AXIS-NOVA manufactured by KRATOS
X-ray source: monochromated Al-Kα
X-ray source power: 15 kV, 10 mA
Analysis area: 300 x 700 μm
Analysis: neutralization gun used for charge correction Sample size: 1 x 1 cm
The results of the XPS analysis are shown in Table 4.

TOF-SIMS analysis conditions: Pretreatment: Surface etching with Ar-GCIB GCIB: 5 kV, 5 μA
GCIB processing time: the point at which the TOF-SIMS spectrum pattern no longer changes. Analytical equipment: PHI nano-TOFII manufactured by ULVAC-PHI.
Primary ion: _Bi32 ⁺
Primary ion source output: 30 kV, 0.5 μA
Analysis area: 300×300 μm (scanning area of primary ion beam)
During the analysis, charge neutralization was performed by irradiating the sample with a low-energy electron beam and low-energy Ar ions attached to the apparatus.
The results of analyzing the data obtained by TOF-SIMS analysis based on the above-mentioned method are shown in Table 5. In Table 5, the relative mass peak intensity normalized by the intensity of C ₃ H ₃ O ₂ ^- is the value obtained by dividing the mass peak intensity of the fragment by the intensity I(C ₃ H ₃ O ₂ ^- ) of C ₃ H ₃ O ₂ ^- .

(4) Preparation of a gas barrier laminate with 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 bonded to the gas barrier surface of the gas barrier laminate obtained in (2) above to prepare a gas barrier laminate with a two-layer laminate structure. The adhesive used was a mixture of 9 parts by mass of Mitsui Chemicals' product name: Takelac A5252S, 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 gas barrier laminate having 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 Tocello, 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 above laminate, and the laminate was bonded to the gas barrier surface of the gas barrier laminate obtained in (2) above to produce a gas barrier laminate having a three-layer laminate structure. The adhesive used was the same as in (4) above.

(6) Evaluation of gas barrier properties after retort treatment The gas barrier laminate obtained in (4) and (5) was folded back so that the non-oriented polypropylene was on the inner surface, and the two sides were heat-sealed to form a bag. Then, 70 cc of water was poured in as the content, and the other side was heat-sealed to prepare a bag. This bag was treated at 130°C for 30 minutes in a high-temperature, high-pressure retort sterilizer. After the retort treatment, the water in the content was removed, 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 under conditions of 20° C. and 90% RH in accordance with JIS K 7126 using OX-TRAN2/21 manufactured by Mocon Corporation.
In addition, the film obtained by the above-mentioned method after retort treatment was folded over so that the unstretched polypropylene was on the inner side, and the gas barrier laminate film was folded over and the two sides were heat-sealed to form a bag. Then, calcium chloride was put in as the content, and the other side was heat-sealed to form a bag with a surface area of 0.01 ^m2 . Then, the bag was left for 300 hours under the conditions of 40°C and 90% RH. The water vapor transmission rate [g/( ^m2 ·day)] was measured based on the weight change before and after leaving it.
The results of the gas barrier property evaluation after retort treatment are shown in Table 6.

Example 2
A gas barrier laminate was produced in the same manner as in Example 1, except that 0.03 mol of ammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ) was used per 1 mol of carboxyl groups in polyacrylic acid. The production conditions are also shown in Table 3. Furthermore, XPS analysis and TOF-SIMS analysis were carried out on the gas barrier layer of the obtained gas barrier laminate. The results of the XPS analysis and TOF-SIMS analysis are also shown in Tables 4 and 5. Furthermore, the results of the gas barrier property evaluation after retort treatment are also shown in Table 6.

Example 3
A gas barrier laminate was produced in the same manner as in Example 1, except that 0.05 mol of ammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ) was used per 1 mol of carboxyl groups in polyacrylic acid. The production conditions are also shown in Table 3. Furthermore, XPS analysis and TOF-SIMS analysis were carried out on the gas barrier layer of the obtained gas barrier laminate. The results of the XPS analysis and TOF-SIMS analysis are also shown in Tables 4 and 5. Furthermore, the results of the gas barrier property evaluation after retort treatment are also shown in Table 6.

Comparative Example
A gas barrier laminate was produced in the same manner as in Example 1, except that ammonium phosphate was not added. The production conditions are also shown in Table 3. Furthermore, XPS analysis and TOF-SIMS analysis were performed on the gas barrier layer of the obtained gas barrier laminate. The results of the XPS analysis and the TOF-SIMS analysis are also shown in Tables 4 and 5. Furthermore, the results of the gas barrier property evaluation after the retort treatment are also shown in Table 6. However, after the retort treatment, some delamination occurred in the gas barrier laminate.

As described above, the gas barrier properties of the gas barrier laminate of the Comparative Example, which does not contain a phosphorus compound and in which the mass peak of the ⁶⁴ ZnPO ₄ H ^-fragment is not detected, after the retort treatment are lower than those of Examples 1 to 3. In addition, some delamination occurred.

1 Two-layer laminate structure barrier film 2 Base material layer 3 Undercoat layer (UC layer)
4 Inorganic layer 5 Gas barrier layer (OC layer)
6 Adhesive layer 7 Non-oriented polypropylene film (CCP)
8 Barrier laminate 9 Nylon film 10 Three-layer laminate structure barrier film 61 First adhesive layer 62 Second adhesive layer

Claims (7)

A gas barrier layer provided on at least one surface of the base layer, and an inorganic layer provided between the base layer and the gas barrier layer,
the gas barrier layer has a Zn composition ratio of 1 to 10 atomic %, as measured by X-ray photoelectron spectroscopy;
The gas barrier layer is subjected to time-of-flight secondary ion mass spectrometry, and the mass peak intensity of ⁶⁴ ZnPO ₄ H ^- is defined as I( ⁶⁴ ZnPO ₄ H ^- ) and the mass peak intensity of C ₃ H ₃ O ₂ ^- is defined as I(C ₃ H ₃ O ₂ ^- ).
^I ( ^64ZnPO4H _- ⁾ /I _{( C3H3O2- )}
The gas barrier laminate has a value of 7×10 ⁻⁴ or more and 5×10 ⁻² or less. The gas barrier layer is measured by time-of-flight secondary ion mass spectrometry, and when the mass peak intensity of PO ₂ ^- is I(PO ₂ ^- ) and the mass peak intensity of PO ₃ ^- is I(PO ₃ ^- ),
(I( _PO2- ⁾ + ^I ( _PO3- ⁾ ) / I _{( C3H3O2- )}
The gas barrier laminate according to claim 1 , wherein the value of is 0.02 or more and 5 or less. The intensity ratio of I(PO ₂ ⁻ ) to I(PO ₃ ⁻ ), I(PO ₂ ⁻ )/I(PO ₃ ⁻ ),
The gas barrier laminate according to claim 1 or 2, wherein the value of is 0.05 or more and 1 or less. The gas barrier laminate according to any one of claims 1 to 3, wherein the gas barrier layer is composed of a cured product of a mixture containing at least a polycarboxylic acid, Zn, and a phosphorus compound or a salt thereof containing one or more -P-OH groups. 5. The gas barrier laminate according to claim 4, wherein the concentration of the phosphorus compound containing one or more -P-OH groups or its salt in the mixture is 5×10 ^-4 mol or more and 0.3 mol or less per mol of carboxyl groups in the polycarboxylic acid. The gas barrier laminate according to claim 4 or 5, 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. The gas barrier laminate according to any one of claims 1 to 6, wherein the thickness of the gas barrier layer is 0.05 μm or more and 10 μm or less.

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