Laminates and packaging bags

Abstract

To provide a laminate comprising a paper substrate and an aluminum vapor-deposited layer, which can suppress the deterioration of water vapor barrier properties over a long period of time, and a packaging bag containing the same. [Solution] A laminate having a structure in which at least a paper substrate, a first resin layer, an aluminum vapor-deposited layer, and a second resin layer are laminated in this order, wherein the thickness of the aluminum vapor-deposited layer is greater than 100 nm, and the full width at half maximum of the peak of the (111) crystal plane of aluminum in the X-ray diffraction measurement of the aluminum vapor-deposited layer is 2.0° or more and 14.0° or less.

Description

Technical Field

[0001] The present disclosure relates to a laminate and a packaging bag.

Background Art

[0002] In many fields such as food, beverages, pharmaceuticals, and chemicals, packaging materials corresponding to each content are used. The packaging material is required to have gas barrier properties such as preventing the permeation of water vapor and the like, which cause the deterioration of the content.

[0003] In recent years, due to the increasing environmental awareness triggered by problems such as marine plastic waste, the movement to reduce plastics has been growing. From the perspective of reducing the usage amount of plastic materials, in various fields, the use of paper instead of plastic materials has been considered. Furthermore, from the perspective of the Law for the Promotion of Effective Use of Resources, it is required to increase the ratio of paper in the entire gas barrier laminate. For example, in Patent Document 1 below, a gas barrier laminate is disclosed which includes a paper base material, an anchor coat layer containing a specific polyolefin, a vapor deposition layer, and an overcoat layer containing a specific polyolefin, in this order.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

Means for Solving the Problems

[0007] One aspect of the present disclosure provides the following laminate and packaging bag. [1] A laminate having a structure in which at least a paper substrate, a first resin layer, an aluminum vapor deposition layer, and a second resin layer are laminated in this order, where the thickness of the aluminum vapor deposition layer is more than 100 nm, and the half-value width of the peak of the (111) crystal plane of aluminum in the X-ray diffraction measurement of the aluminum vapor deposition layer is 2.0° or more and 14.0° or less. [2] The laminate according to [1], wherein the second resin layer contains a polyolefin having an acidic group. [3] The laminate according to [1] or [2], wherein the first resin layer contains at least one selected from the group consisting of a polyolefin having an acidic group, a polyvinyl alcohol-based resin, and a polyurethane-based resin. [4] The laminate according to any one of [1] to [3], having a water vapor permeability of 5 g / (m 2 ·day) or less at a temperature of 40°C and a relative humidity of 90%. [5] The laminate according to any one of [1] to [4], wherein the second resin layer contains an ethylene-unsaturated carboxylic acid copolymer. [6] The laminate according to any one of [1] to [5], wherein the thickness of the aluminum vapor deposition layer is 200 nm or less. [7] The laminate according to any one of [1] to [6], wherein the first resin layer contains a polyolefin having an acidic group, and in the IR spectrum of the first resin layer, the ratio of the area of the peak between 1620 and 1770 cm -1 derived from the carboxy group to the area of the peak between 1490 and 1620 cm -1 derived from the salt of the carboxy group is 0.1 or less. [8] The second resin layer contains a polyolefin having an acidic group, In the IR spectrum of the second resin layer described above, the 1620-1770 cm⁻¹ range originates from the carboxyl group. -1 The area of ​​the peak between 1490 and 1620 cm² is derived from the carboxyl group salt. -1 A laminate according to any one of [1] to [7], wherein the ratio of the areas of the peaks between them is 0.1 or less. [9] The first resin layer contains ethylene-modified polyvinyl alcohol, The laminate according to any one of [1] to [8], wherein the second resin layer comprises a polyolefin having an acidic group.

[10] A packaging bag containing a laminate as described in any of [1] to [9]. [Effects of the Invention]

[0008] According to this disclosure, a laminate comprising a paper substrate and an aluminum vapor-deposited layer is provided, which can suppress the deterioration of water vapor barrier properties over a long period of time, and a packaging bag containing the same. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic cross-sectional view showing a laminate according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a perspective view showing a packaging bag according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described in detail below, with reference to the drawings as appropriate. However, this disclosure is not limited to the embodiments described below.

[0011] <Laminate> Figure 1 is a schematic cross-sectional view showing the laminate according to this embodiment. As shown in Figure 1, the laminate 10 according to this embodiment has a structure in which a paper substrate 3, a first resin layer 1, an aluminum vapor-deposited layer 4, and a second resin layer 2 are laminated in this order. The thickness of the aluminum vapor-deposited layer 4 is more than 100 nm. The full width at half maximum of the peak of the (111) crystal plane of aluminum in the X-ray diffraction measurement of the aluminum vapor-deposited layer 4 is between 2.0° and 14.0°.

[0012] The laminate 10 comprises a paper substrate and an aluminum vapor-deposited layer, and can suppress the deterioration of its water vapor barrier properties over a long period of time. On the other hand, conventional laminates experience a decrease in water vapor barrier properties over a long period of time. The inventors of the present invention speculate on the reasons for these differences as follows.

[0013] When conventional laminates are observed under a microscope using transmitted light after a long period of time, tiny bright spots are observed in the aluminum vapor-deposited layer, which acts as a light-shielding layer, due to light transmission. These bright spots are observed because light has been transmitted through minute defects in the aluminum vapor-deposited layer. If there are many of these minute defects, water vapor can permeate through them, reducing the water vapor barrier properties. The inventors believe that the generation of these minute defects is due to pitting corrosion of aluminum by corrosive ions and expansion and contraction stress caused by dimensional changes due to moisture absorption and dehydration of the paper substrate. To reduce these minute defects, the inventors first changed the thickness of the aluminum vapor-deposited layer. As a result, when the thickness of the aluminum vapor-deposited layer exceeded 100 nm, the number of minute defects thought to be caused by pitting corrosion decreased, but there was still room for improvement.

[0014] Next, the inventors focused on the crystallinity of aluminum. Considering only the corrosion resistance of the aluminum vapor-deposited layer, higher crystallinity of aluminum makes it less susceptible to corrosion. Therefore, it is thought that a narrower half-width of aluminum reduces the number of minute defects caused by corrosion. Incidentally, when forming a laminate using a roll-to-roll method, the laminate is transported to a vacuum deposition apparatus equipped with a deposition chamber where aluminum has evaporated. The thickness of the aluminum vapor-deposited film can be increased by slowing down the transport speed of the laminate. Slowing down the transport speed reduces the amount of paper substrate passing through the deposition chamber per unit time, which reduces the amount of water evaporating from the paper substrate, thus lowering the pressure in the deposition chamber and increasing the crystallinity of the aluminum. In other words, the crystallinity of the aluminum vapor-deposited layer is higher when the thickness exceeds 100 nm compared to when the thickness is 100 nm or less. However, regarding resistance to the stretching stress applied to the aluminum vapor-deposited layer due to dimensional changes in the paper substrate, amorphous aluminum, which is more adaptable to stretching, is considered superior. Here, it is thought that the aluminum vapor-deposited layer has a structure in which amorphous regions fill the crystallites. Furthermore, the broadening of the X-ray diffraction linewidth of aluminum is due to the crystallite diameter and crystal distortion. A narrow X-ray diffraction linewidth is thought to indicate a state where the crystallites, consisting of an ideal crystal lattice, are clearly separated from the amorphous region. Therefore, it is presumed that when the X-ray diffraction linewidth is narrow, fracture due to stretching stress is more likely to occur in the ideal crystal lattice or between the crystal and amorphous regions. On the other hand, a broad X-ray diffraction linewidth is thought to indicate a distorted crystal structure, where the separation between the crystalline and amorphous regions is ambiguous. Therefore, it is presumed that when the X-ray diffraction linewidth is broad, fracture due to stretching stress is suppressed, and the occurrence of minute defects is less likely to occur.

[0015] The inventors have found that while increasing the thickness of the aluminum vapor deposition layer to over 100 nm increases crystallinity, deliberately setting the above-mentioned full width at half maximum of aluminum to 2.0° or more and 14.0° or less suppresses the deterioration of water vapor barrier properties over a long period of time.

[0016] The thickness of the laminate 10 may be 20 to 100 μm, may be 30 to 80 μm, or may be 40 to 60 μm. When the thickness of the laminate 10 is within the above range, the laminate 10 tends to maintain a higher water vapor barrier property for a longer period.

[0017] The water vapor permeability of the gas barrier laminate 10 at a temperature of 40 °C and a relative humidity of 90% is 5 g / (m 2 ·day) or less, 4 g / (m 2 ·day) or less, 3 g / (m 2 ·day) or less, 2 g / (m 2 ·day) or less, or 1 g / (m 2 ·day) or less. Here, the water vapor permeability may be a value measured by the Mocon method in accordance with JIS K7129-2 for the water vapor permeability (g / m 2 / day) in an atmosphere of 40 °C and 90% RH.

[0018] Hereinafter, each layer of the laminate 10 will be described.

[0019] [Paper substrate] The paper substrate 3 may be paper mainly composed of plant-derived pulp. Specific examples of the paper substrate 3 include high-quality paper, special high-quality paper, coated paper, art paper, cast-coated paper, imitation paper, kraft paper, and glassine paper. The basis weight of the paper substrate 3 is 20 to 500 g / m 2 , or 30 to 100 g / m 2 and may be.

[0020] The paper substrate 3 may have a coating layer on at least the side of the paper substrate 3 that is in contact with the first resin layer 1. If the paper substrate 3 has a coating layer, the paper substrate 3 may have at least a paper layer and a coating layer. The coating layer may be provided on both surfaces of the paper substrate 3. By providing a coating layer, it is possible to prevent the first resin layer 1 from seeping into the paper, and it can also act as a sealer to fill in the irregularities of the paper, allowing the first resin layer 1 to be formed uniformly without defects. For example, the coating layer may use various copolymers such as styrene-butadiene, styrene-acrylic, and ethylene-vinyl acetate as binder resins, polyvinyl alcohol resins, cellulose resins, paraffin (wax), etc., and may contain clay, kaolin, calcium carbonate, talc, mica, etc. as fillers. The coating layer may be a clay coating layer containing at least clay as a filler.

[0021] The change rate in the width direction (CD) of the dimensions of the paper substrate 3 in a 40°C 90%RH environment relative to the dimensions in a 40°C 20%RH environment may be 0.3% or more, 0.4% or more, or 0.6% or more, and may be 1.5% or less, 1.3% or less, or 1.0% or less. The change rate in the flow direction (MD) of the dimensions of the paper substrate 3 in a 40°C 90%RH environment relative to the dimensions in a 40°C 20%RH environment may be 0.05% or more, and may be 0.20% or less.

[0022] If the paper substrate 3 has a coating layer, the thickness of the coating layer may be 1.5 μm or more and 15 μm or less. The thickness of the coating layer may be 1.8 μm or more, 3 μm or more, 5 μm or more, or 6 μm or more. The thickness of the coating layer may be 12 μm or less, or 10 μm or less. When the thickness of the coating layer is within the above range, the laminate 10 tends to be able to maintain higher water vapor barrier properties for a longer period of time.

[0023] The thickness of the paper substrate 3 may be 20 to 100 μm, 30 to 80 μm, or 40 to 60 μm. When the thickness of the paper substrate 3 is within the above range, the laminate 10 tends to maintain higher water vapor barrier properties for a longer period of time.

[0024] When the paper substrate 3 is equipped with a coating layer, the ratio of the thickness of the coating layer to the thickness of the paper substrate 3 may be 3 to 25%, or 5 to 20%. When this ratio is within the above range, the laminate 10 tends to maintain higher water vapor barrier properties for a longer period of time.

[0025] The weight of paper is preferably 50% or more by mass of the entire laminate, more preferably 70% or more by mass, and even more preferably 80% or more by mass. If the weight of paper is 50% or more by mass of the entire laminate, the amount of plastic material used can be sufficiently reduced, the entire laminate can be said to be made of paper, and it has excellent recyclability.

[0026] [First resin layer] The first resin layer 1 is provided on the surface of the paper substrate 3 to improve adhesion between the paper substrate 3 and the aluminum vapor-deposited layer 4, and to improve the gas barrier properties of the laminate. The first resin layer 1 may contain at least one selected from the group consisting of polyolefins having acidic groups, polyvinyl alcohol-based resins, and polyurethane-based resins.

[0027] When the first resin layer 1 contains a polyolefin having acidic groups, the first resin layer 1 exhibits excellent flexibility, suppressing cracking of the aluminum vapor-deposited layer 4 after bending (folding), and improving adhesion between the first resin layer 1 and the aluminum vapor-deposited layer 4. Furthermore, the inclusion of a polyolefin having acidic groups enables the formation of a dense film due to the crystalline nature of the polyolefin, resulting in water vapor barrier properties. The crystalline nature of the polyolefin provides water vapor barrier properties, and the presence of acidic groups ensures adhesion with the aluminum vapor-deposited layer 4.

[0028] The polyolefin having an acidic group may have at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic acid anhydride group, and a carboxylic acid ester.

[0029] As the acidic polyolefin, copolymers of ethylene or propylene with unsaturated carboxylic acids (unsaturated compounds having carboxyl groups such as acrylic acid, methacrylic acid, and maleic anhydride), unsaturated carboxylic acid esters, and salts obtained by neutralizing carboxylic acids with basic compounds may be used. In addition, copolymers with vinyl acetate, epoxy compounds, chlorine compounds, urethane compounds, polyamide compounds, etc., may also be used.

[0030] Examples of polyolefins having acidic groups include copolymers of acrylic acid esters and maleic anhydride, and ethylene-unsaturated carboxylic acid copolymers. Ethylene-unsaturated carboxylic acid copolymers are preferred as polyolefins having acidic groups because they tend to maintain higher water vapor barrier properties for longer periods of time. Examples of ethylene-unsaturated carboxylic acid copolymers include ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, and ethylene-glycidyl methacrylate copolymers.

[0031] According to the inventors' studies, when the first resin layer adjacent to the aluminum vapor-deposited layer contains metal ions such as sodium or potassium, prolonged storage of the laminate can cause the metal ions to pit the aluminum, resulting in pinhole defects in the aluminum vapor-deposited layer. These pinhole defects in the aluminum vapor-deposited layer can worsen the long-term water vapor barrier properties of the laminate. Therefore, when using a polyolefin having acidic groups in the first resin layer, a resin in which the acidic groups are neutralized with ammonia, which evaporates during the drying process and does not remain in the dried film (for example, Sumitomo Seika's Zaixen AC) is preferred over so-called ionomer resins in which the acidic groups are neutralized with sodium hydroxide or potassium hydroxide (for example, Mitsui Chemicals' ChemiPearl series). By using a resin in which the acidic groups are neutralized with ammonia, pitting corrosion of the aluminum vapor-deposited layer can be suppressed even when the laminate is stored for a long period of time, and the aluminum vapor-deposited layer can be made thinner.

[0032] The remaining amount of metal ions can be confirmed by the IR spectrum of the first resin. The area of ​​the peak originating from the carboxyl group (A COOH The area of ​​the peak (A) derived from the carboxyl group salt relative to ) COOX ) ratio (A COOX / A COOH By setting the ratio to 0.1 or less, it is possible to suppress pitting corrosion of the aluminum vapor-deposited layer even when the laminate is stored for a long period of time.

[0033] In the IR spectrum, the peak originating from the carboxyl group is located at 1620–1770 cm⁻¹. -1 Between (1700cm) -1 The peaks appearing in the vicinity, originating from carboxyl group salts, are generally between 1490 and 1620 cm, depending on the type of salt. -1 It appears between these points. For example, peaks originating from the sodium salt and potassium salt of the carboxyl group appear at 1540 cm⁻¹. -1 It appears nearby. The peak originating from the ammonium salt of the carboxyl group is at 1520 cm. -1 It appears in the vicinity. By calculating the area of ​​such peaks, the area of ​​the peak originating from the carboxyl group (A COOH) and the area of ​​the peak derived from the salt of the carboxyl group (A COOX ) can be obtained.

[0034] When the first resin layer 1 contains a polyvinyl alcohol-based resin, the polyvinyl alcohol-based resin has hydroxyl groups, and these hydroxyl groups readily bond with metals such as aluminum in the aluminum vapor-deposited layer 4, thereby improving the adhesion between the aluminum vapor-deposited layer 4 and the first resin layer 1. Furthermore, such a first resin layer 1 has excellent flexibility, which can suppress cracking of the aluminum vapor-deposited layer 4 after bending (folding). In addition, the inclusion of a polyvinyl alcohol-based resin in the first resin layer 1 can improve the oxygen barrier properties of the laminate.

[0035] Polyvinyl alcohol-based resins are resins that contain vinyl alcohol as a constituent unit. Examples of polyvinyl alcohol-based resins include fully saponified polyvinyl alcohol resins, partially saponified polyvinyl alcohol resins, modified polyvinyl alcohol resins, and ethylene-vinyl alcohol copolymer resins.

[0036] Examples of modified polyvinyl alcohol resins include ethylene-modified polyvinyl alcohol, propylene-modified polyvinyl alcohol, and butene-modified polyvinyl alcohol. The polyvinyl alcohol resin is preferably ethylene-modified polyvinyl alcohol. Because the laminate 10 uses paper as its base material, it exhibits significant dimensional changes, and these changes can affect the first resin layer, and even the aluminum vapor-deposited layer and the second resin layer. Since ethylene-modified polyvinyl alcohol has a lower elastic modulus than unmodified polyvinyl alcohol, it mitigates the effects of dimensional changes in the paper base material, suppressing the occurrence of micro-defects in the first resin layer. It also mitigates the influence of dimensional changes in the paper base material on the aluminum vapor-deposited layer and the second resin layer, thereby suppressing the occurrence of micro-defects in these layers. As a result, the laminate 10 tends to exhibit superior water vapor barrier properties.

[0037] Preferably, the laminate 10 contains ethylene-modified polyvinyl alcohol as a polyvinyl alcohol-based resin in the first resin layer 1, and a polyolefin having an acidic group, as described later, in the second resin layer 2. This combination of resins in the first and second resin layers tends to mitigate the effects of dimensional changes in the paper substrate, further suppressing the occurrence of cracks and pinholes in the aluminum vapor-deposited layer and the second resin layer. As a result, the laminate 10 tends to have even better water vapor barrier properties.

[0038] Ethylene-modified polyvinyl alcohol can be obtained, for example, by saponifying an ethylene-vinyl acetate copolymer.

[0039] The ethylene unit content in ethylene-modified polyvinyl alcohol is preferably 1 mol% or more, more preferably 2 mol% or more, and even more preferably 3 mol% or more, since the laminate 10 tends to have superior water vapor barrier properties. From the viewpoint of the coating properties and oxygen barrier properties of the ethylene-modified polyvinyl alcohol solution, the ethylene unit content in ethylene-modified polyvinyl alcohol is preferably 30 mol% or less, more preferably 20 mol% or less, and even more preferably 10 mol% or less.

[0040] The degree of saponification of the polyvinyl alcohol-based resin is preferably high from the viewpoint of further enhancing oxygen barrier properties, and may be 90 mol% or more, 95 mol% or more, or 98 mol% or more. The degree of saponification of the polyvinyl alcohol-based resin is preferably low from the viewpoint of enhancing water solubility, and may be 99.5 mol% or less.

[0041] The degree of polymerization of the polyvinyl alcohol-based resin is preferably high from the viewpoint of mitigating the effects of dimensional changes in the paper substrate and suppressing the occurrence of cracks and pinholes in the aluminum vapor-deposited layer, and may be 300 or more, 600 or more, or 1000 or more. The degree of polymerization of the polyvinyl alcohol-based resin is preferably low from the viewpoint of improving the coating properties of the polyvinyl alcohol-based resin solution, and may be 2000 or less, 1700 or less, or 1500 or less.

[0042] Polyurethane resins are obtained by bonding the acid groups of acid group-containing polyurethane to the amino groups of polyamine, which is used as a crosslinking agent. In other words, polyurethane resins can be described as a reaction product of acid group-containing polyurethane and polyamine, or as acid group-containing polyurethane crosslinked with polyamine. The bond between the acid groups of the acid group-containing polyurethane and the amino groups of the polyamine may be an ionic bond (for example, an ionic bond between a carboxyl group and a tertiary amino group) or a covalent bond (for example, an amide bond).

[0043] Polyurethane containing acid groups, which constitutes polyurethane resins, possesses anionic and self-emulsifying properties due to the presence of acid groups, and is also referred to as anionic self-emulsifying polyurethane. The acid groups of acid group-containing polyurethane can bond to the amino groups (primary amino groups, secondary amino groups, tertiary amino groups, etc.) of the polyamines that constitute the polyurethane resin. Examples of acid groups include carboxyl groups and sulfonic acid groups. Acid groups can usually be neutralized with a neutralizing agent (base) and may form a salt with the base. Acid groups may be located at the ends of the acid group-containing polyurethane or on the side chains, but it is preferable that they are located on the side chains at least.

[0044] The acid value of the acid group-containing polyurethane can be selected within the range in which the acid group-containing polyurethane is water-dispersible, and can be 5 to 100 mg KOH / g, 10 to 70 mg KOH / g, or 15 to 60 mg KOH / g. If the acid value of the acid group-containing polyurethane is above the lower limit of the above range, water dispersibility of the acid group-containing polyurethane is easily obtained, and uniform dispersion between the polyurethane resin and other materials, as well as dispersion stability of the coating agent, is easily ensured. If the acid value of the acid group-containing polyurethane is below the upper limit of the above range, water resistance and gas barrier properties of the first resin layer 1 are easily ensured. The acid value of the acid group-containing polyurethane is measured by a method in accordance with JIS K 0070.

[0045] The total concentration of urethane groups and urea groups in the acid group-containing polyurethane can be 15% by mass or more, and may be 20 to 60% by mass, from the viewpoint of gas barrier properties. If the total concentration of urethane groups and urea groups is above the lower limit, the gas barrier properties of the first resin layer 1 tend to be good. If the total concentration of urethane groups and urea groups is below the upper limit of the above range, it is easier to suppress the rigidity and brittleness of the first resin layer 1.

[0046] The urethane group concentration refers to the ratio of the molecular weight of the urethane group (59 g / equivalent) to the molecular weight of the constituent units of the polyurethane resin. The urea group concentration refers to the ratio of the molecular weight of the urea group (primary amino group: 58 g / equivalent, secondary amino group: 57 g / equivalent) to the molecular weight of the constituent units of the polyurethane resin. When using a mixture of two or more acid group-containing polyurethanes, the urethane group concentration and urea group concentration can be calculated based on the base of the reaction components, i.e., the usage ratio of each component.

[0047] Acid group-containing polyurethanes may have at least rigid units (units composed of hydrocarbon rings) and short-chain units (for example, units composed of hydrocarbon chains). The constituent units of acid group-containing polyurethanes may contain hydrocarbon rings (at least one of aromatic and non-aromatic hydrocarbon rings) derived from polyisocyanate components, polyhydroxy acid components, polyol components, and chain extension components (in particular, at least polyisocyanate components). From the viewpoint of improving oxygen barrier properties, polyurethane resins may contain aromatic rings, and therefore, the constituent units of acid group-containing polyurethanes may contain aromatic hydrocarbon rings as hydrocarbon rings.

[0048] The proportion of units composed of hydrocarbon rings in the constituent units of acid group-containing polyurethane can be 10 to 70% by mass, 15 to 65% by mass, or 20 to 60% by mass, relative to the total of all constituent units. If the proportion of units composed of hydrocarbon rings is above the lower limit of the above range, the gas barrier properties of the first resin layer 1 tend to be good. If the proportion of units composed of hydrocarbon rings is below the upper limit of the above range, it is easier to suppress the rigidity and brittleness of the first resin layer 1.

[0049] The number-average molecular weight of the acid-containing polyurethane can be appropriately selected, but can be between 800 and 1,000,000, or between 800 and 200,000, or between 800 and 100,000. If the number-average molecular weight of the acid-containing polyurethane is below the upper limit of the above range, it is easier to obtain an appropriate viscosity for the coating agent. If the number-average molecular weight of the acid-containing polyurethane is above the lower limit of the above range, it is easier to obtain good gas barrier properties for the first resin layer 1. The number-average molecular weight of the acid-containing polyurethane is a value on a standard polystyrene basis measured by gel permeation chromatography (GPC).

[0050] The acid group-containing polyurethane may be crystalline to enhance its gas barrier properties. The glass transition temperature of the acid group-containing polyurethane can be 100°C or higher, 110°C or higher, or 120°C or higher. When the glass transition temperature of the acid group-containing polyurethane is 100°C or higher, the gas barrier properties of the first resin layer 1 tend to be good. The glass transition temperature of the acid group-containing polyurethane can be 200°C or lower, 180°C or lower, or 150°C or lower. Therefore, the glass transition temperature of the acid group-containing polyurethane can be 100 to 200°C, 110 to 180°C or 120 to 150°C. The glass transition temperature of the acid group-containing polyurethane is measured by differential scanning calorimetry (DSC).

[0051] Polyamines constituting polyurethane resins are compounds having two or more basic nitrogen atoms. Basic nitrogen atoms are nitrogen atoms that can bond to the acid groups of acid-containing polyurethanes, and examples include nitrogen atoms in amino groups such as primary amino groups, secondary amino groups, and tertiary amino groups. The polyamine is not particularly limited as long as it can bond to the acid groups of acid-containing polyurethanes and improve gas barrier properties; various compounds having two or more basic nitrogen atoms can be used. As a polyamine, a polyamine having two or more amino groups selected from the group consisting of primary amino groups, secondary amino groups, and tertiary amino groups can be used.

[0052] Examples of polyamines include alkylenediamines, polyalkylene polyamines, and silicon compounds having multiple basic nitrogen atoms. Examples of alkylenediamines include alkylenediamines having 2 to 10 carbon atoms, such as ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,4-butanediamine, and 1,6-hexamethylenediamine. Examples of polyalkylene polyamines include tetraalkylene polyamines. Examples of silicon compounds having multiple basic nitrogen atoms (including nitrogen atoms such as amino groups) include silane coupling agents having multiple basic nitrogen atoms, such as 2-[N-(2-aminoethyl)amino]ethyltrimethoxysilane and 3-[N-(2-aminoethyl)amino]propyltriethoxysilane.

[0053] The amine value of the polyamine can be 100-1900 mgKOH / g, 150-1900 mgKOH / g, 200-1900 mgKOH / g, 200-1700 mgKOH / g, or 300-1500 mgKOH / g. If the amine value of the polyamine is above the lower limit of the above range, the gas barrier properties of the first resin layer 1 tend to be good. If the amine value of the polyamine is below the upper limit of the above range, the water dispersion stability of the polyurethane resin tends to be good.

[0054] [Method for measuring amine value] The amine value of polyamines is measured by the following method. Weigh 0.5 to 2 g of the sample accurately (sample amount S g). Add 30 g of ethanol to the weighed sample and dissolve it. Add bromophenol blue as an indicator to the resulting solution and titrate with a 0.2 mol / L ethanolic hydrochloric acid solution (titer f). The endpoint is the point where the color of the solution changes from green to yellow, and the amine value is calculated using the titration volume (A mL) at this point and formula 1 below. Formula 1: Amine value = A × f × 0.2 × 56.108 / S [mgKOH / g]

[0055] When forming a polyurethane resin, the molar ratio (acid group / basic nitrogen atom) of the acid group-containing polyurethane to the basic nitrogen atom of the polyamine can be 10 / 1 to 0.1 / 1, or 5 / 1 to 0.2 / 1. If the acid group / basic nitrogen atom ratio is within the above range, the first resin layer 1 is likely to exhibit excellent oxygen barrier properties.

[0056] As the polyurethane resin, commercially available polyurethane resins may be used, or polyurethane resins manufactured by known manufacturing methods may be used.

[0057] The method for producing polyurethane resins is not particularly limited, and common aqueous polyurethane resin production techniques such as the acetone method and the prepolymer method can be used. In the urethane reaction, urethane catalysts such as amine-based catalysts, tin-based catalysts, and lead-based catalysts may be used as needed. For example, an acid group-containing polyurethane can be prepared by reacting a polyisocyanate compound with a polyhydroxy acid and, if necessary, at least one of a polyol component and a chain extender component in an inert organic solvent such as ketones such as acetone, ethers such as tetrahydrofuran, or nitriles such as acetonitrile. More specifically, an aqueous dispersion of acid group-containing polyurethane can be prepared by reacting a polyisocyanate compound with a polyhydroxy acid and a polyol component in an inert organic solvent (particularly a hydrophilic or water-soluble organic solvent) to produce a prepolymer having isocyanate groups at the ends, neutralizing it with a neutralizing agent and dissolving or dispersing it in an aqueous medium, then adding a chain extender component and reacting it, and finally removing the organic solvent. By adding a polyamine to the aqueous dispersion of the acid group-containing polyurethane obtained in this way and heating it as needed, a polyurethane resin in the form of an aqueous dispersion can be prepared. When heating, the heating temperature can be 30 to 60°C.

[0058] The first resin layer 1 may contain other components in addition to the polyolefin having an acidic group, polyvinyl alcohol-based resin, and polyurethane-based resin. Examples of other components include polyolefins other than the above-mentioned polyolefin having an acidic group, silane coupling agents, organic titanates, polyacrylics, polyesters, polyurethanes, polycarbonates, polyureas, polyamides, polyimides, melamines, phenols, and the like.

[0059] The content of at least one material selected from the group consisting of polyolefins, polyvinyl alcohol-based resins, and polyurethane-based resins having acidic groups in the first resin layer 1 may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass.

[0060] The thickness of the first resin layer 1 may be, for example, 0.5 μm or more, 1 μm or more, 2 μm or more, 20 μm or less, 10 μm or less, or 5 μm or less. If the thickness of the first resin layer 1 is 0.5 μm or more, the irregularities of the paper substrate described above can be efficiently filled, and the aluminum vapor-deposited layer described later can be uniformly laminated. Also, if the thickness of the first resin layer 1 is 20 μm or less, the aluminum vapor-deposited layer can be uniformly laminated while keeping costs down.

[0061] Examples of solvents included in the coating solution for the first resin layer 1 include water, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, n-pentyl alcohol, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, toluene, hexane, heptane, cyclohexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, and butyl acetate. These solvents may be used individually or in combination of two or more. Among these, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred from the viewpoint of properties. Furthermore, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferred from the viewpoint of environmental impact.

[0062] The first resin layer 1 can be obtained by applying a coating solution containing the above-mentioned acidic group-containing polyolefin, polyvinyl alcohol-based resin, or polyurethane-based resin and a solvent, etc., onto a paper substrate 3 to form a coating film, and then drying the coating film.

[0063] [Aluminum vapor-deposited layer] The aluminum vapor-deposited layer 4 is a layer on which aluminum or an aluminum compound has been deposited. The aluminum vapor-deposited layer may be obtained by depositing aluminum, or aluminum oxide (AlO x ), silicon dioxide (SiO₂) x ) and other similar items may also be included.

[0064] The thickness of the aluminum vapor-deposited layer 4 is preferably 105 nm or more, more preferably 110 nm or more, and even more preferably 120 nm or more, as this tends to further suppress the deterioration of water vapor barrier properties over a long period of time. The thickness of the aluminum vapor-deposited layer 4 is preferably 200 nm or less, and more preferably 180 nm or less, from the viewpoint of suppressing curling of the laminate and poor adhesion between layers due to increased internal stress, and also suppressing melting and breakage of the first resin layer due to increased heat load during vapor deposition processing. The thickness of the aluminum vapor-deposited layer 4 may be 100 nm or more and 200 nm or less, 100 nm or more and 180 nm or less, 105 nm or more and 200 nm or less, 105 nm or more and 180 nm or less, 110 nm or more and 200 nm or less, 110 nm or more and 180 nm or less, 120 nm or more and 200 nm or less, or 120 nm or more and 180 nm or less.

[0065] The thickness of the aluminum vapor-deposited layer 4 may be measured by the following procedure: Cut out a sample from the laminate 10 to obtain a measurement sample. Embed the measurement sample in UV-curing resin. Cut the measurement sample using a cryomicrotome to obtain a cross-section sample for cross-sectional observation. Observe the obtained sample with a scanning electron microscope (magnification: 50,000x) and take images of 10 cross-sections from each sample. Measure the thickness of the aluminum vapor-deposited layer for each of the obtained images. The average of the 10 thicknesses is taken as the thickness of the aluminum vapor-deposited layer.

[0066] The full width at half maximum (FWHM) of the peak of the (111) crystal plane of aluminum in the X-ray diffraction measurement of the aluminum vapor-deposited layer 4 is 2.0° or greater, and may be 2.1° or greater, 2.2° or greater, 2.3° or greater, or 2.4° or greater. The above FWHM is 14.0° or less, and may be 13.5° or less, or 13.0° or less. The above half-width may be 2.0° or more and 14.0° or less, 2.0° or more and 13.5° or less, 2.0° or more and 13.0° or less, 2.1° or more and 14.0° or less, 2.1° or more and 13.5° or less, 2.1° or more and 13.0° or less, 2.2° or more and 13.5° or less, 2.2° or more and 13.0° or less, 2.3° or more and 14.0° or less, 2.3° or more and 13.5° or less, 2.3° or more and 13.0° or less, 2.4° or more and 14.0° or less, 2.4° or more and 13.5° or less, or 2.4° or more and 13.0° or less.

[0067] The full width at half maximum (2θ) of the peak of the (111) crystal plane of aluminum in the aluminum vapor-deposited layer 4 is measured using an X-ray diffractometer. For example, an ATX-G (product name) manufactured by Rigaku Electric Co., Ltd. can be used as the X-ray diffractometer. The measurement can be performed on the second resin layer 2 using the laminate as the sample, fixed on a glass slide. For the X-ray diffraction of aluminum, the full width at half maximum of the peak at 2θ = 38.5°, corresponding to the (111) plane (d = 2.34 Å), is measured. The measurement conditions are as follows. Light source: CuKα line Tube voltage: 50kV Tube current: 300mA Optical system: Parallel beam optical system Scanning method: 2θ / θ method Measurement range: 30°~50° Sampling step: 0.02° Scan speed: 2° / min slit S1: 10.0mm x 1.0mm S2: 10.0mm x 0.5mm Sollar(res): 0.4mm

[0068] The above-mentioned full width at half maximum (FWHM) can be controlled by adjusting the conditions during the deposition of the aluminum vapor-deposited layer 4. For example, the FWHM can be controlled by adjusting the pressure inside the deposition chamber during the deposition of the aluminum vapor-deposited layer 4. Increasing the pressure inside the deposition chamber increases the FWHM, while decreasing the pressure inside the deposition chamber decreases the FWHM. The pressure inside the deposition chamber during the deposition of the aluminum vapor-deposited layer 4 may be 0.05 Pa or higher, 0.10 Pa or higher, or 0.20 Pa or higher, as it is easier to adjust the FWHM to 2.0° or higher. The upper limit of the pressure is not particularly limited as long as the deposition of the aluminum vapor-deposited layer 4 is possible, but for example, it may be 0.50 Pa or lower, or 0.40 Pa or lower.

[0069] The aluminum vapor-deposited layer 4 is preferably deposited by a vacuum deposition method from the viewpoint of water vapor and oxygen gas barrier performance, oil resistance, and film uniformity. Known deposition methods include vacuum deposition, sputtering, and chemical vapor deposition (CVD), but vacuum deposition is preferred because it has a fast deposition rate and high productivity. Among vacuum deposition methods, electron beam heating is particularly effective because the deposition rate can be easily controlled by the irradiation area and electron beam current, and the heating and cooling of the deposition material can be performed in a short time.

[0070] [Second resin layer] The second resin layer 2 is provided on the surface of the aluminum vapor-deposited layer 4, in contact with the aluminum vapor-deposited layer 4. The second resin layer 2 may contain a polyolefin having an acidic group.

[0071] The polyolefin having an acidic group may have at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic acid anhydride group, and a carboxylic acid ester.

[0072] As the polyolefin having an acidic group, copolymers of ethylene or propylene with unsaturated carboxylic acids (unsaturated compounds having a carboxyl group, such as acrylic acid and methacrylic acid), unsaturated carboxylic acid esters, and salts obtained by neutralizing the carboxylic acid with a basic compound may be used. In addition, copolymers with vinyl acetate, epoxy compounds, chlorine compounds, urethane compounds, polyamide compounds, etc., may also be used.

[0073] Examples of polyolefins having acidic groups include copolymers of acrylic acid esters and maleic anhydride, and ethylene-unsaturated carboxylic acid copolymers. Ethylene-unsaturated carboxylic acid copolymers are preferred as polyolefins having acidic groups because they tend to maintain higher water vapor barrier properties for longer periods of time. Examples of ethylene-unsaturated carboxylic acid copolymers include ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, and ethylene-glycidyl methacrylate copolymers.

[0074] By containing a polyolefin having acidic groups, the second resin layer 2 exhibits excellent flexibility, suppressing cracking of the aluminum vapor-deposited layer after bending (folding), and also exhibits excellent adhesion to the aluminum vapor-deposited layer. Furthermore, the inclusion of the aforementioned polyolefin having acidic groups enables the formation of a dense film due to the crystalline nature of the polyolefin, resulting in water vapor barrier properties. The presence of acidic groups also contributes to adhesion to the aluminum vapor-deposited layer. Moreover, because the second resin layer 2 contains the above-mentioned polyolefin having acidic groups, it can also function as a heat seal layer, eliminating the need for a separate heat seal layer.

[0075] The second resin layer 2 may contain other components in addition to the polyolefin having the acidic group mentioned above. Examples of other components include silane coupling agents, organic titanates, polyacrylics, polyesters, polyurethanes, polycarbonates, polyureas, polyamides, polyolefin emulsions, polyimides, melamines, phenols, and the like.

[0076] The content of the polyolefin having an acidic group in the second resin layer 2 may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass.

[0077] According to the inventors' studies, when the second resin layer adjacent to the aluminum vapor-deposited layer contains metal ions such as sodium or potassium, if the laminate is stored for a long period of time, the metal ions may pit the aluminum, causing pinhole defects in the aluminum vapor-deposited layer, similar to the first resin layer. When using a polyolefin having acidic groups for the second resin layer, it is preferable to use a resin in which the acidic groups are neutralized by ammonia that evaporates during the drying process and does not remain in the dried film (for example, Zychsen AC manufactured by Sumitomo Seika), similar to the first resin layer.

[0078] The amount of residual metal ions can be confirmed by the IR spectrum of the second resin layer, similar to the first resin layer. (1620-1770 cm⁻¹) -1 Area of ​​the peak between (A COOH ) derived from the carboxyl group salt, 1490-1620 cm -1 Area of ​​the peak between (A COOX ) ratio (A COOX / A COOH By setting the ratio to 0.1 or less, it is possible to suppress pitting corrosion of the aluminum vapor-deposited layer even when the laminate is stored for a long period of time.

[0079] The thickness of the second resin layer 2 may be, for example, 0.05 μm or more, 0.5 μm or more, 1 μm or more, 2 μm or more, 20 μm or less, 10 μm or less, or 5 μm or less. If the thickness of the second resin layer 2 is 0.05 μm or more, it can fully perform the role of a heat seal layer as described above. If the thickness of the second resin layer 2 is 20 μm or less, it can fully exhibit adhesion and barrier properties with the aluminum vapor-deposited layer while keeping costs down. Furthermore, by setting the thickness of the second resin layer 2 to 2 μm or more and 10 μm or less, the aluminum vapor-deposited layer becomes less prone to cracking, and sufficient water vapor barrier properties and oil resistance can be obtained even after bending.

[0080] Examples of solvents included in the coating solution for the second resin layer 2 include water, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, n-pentyl alcohol, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, toluene, hexane, heptane, cyclohexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, and butyl acetate. These solvents may be used individually or in combination of two or more. Among these, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred from the viewpoint of properties. Furthermore, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferred from the viewpoint of environmental impact.

[0081] The second resin layer 2 can be obtained by applying a coating solution containing the above-mentioned polyolefin having acidic groups and a solvent onto the aluminum vapor-deposited layer to form a coating film, and then drying the coating film. The melting point of the polyolefin having acidic groups in the coating solution is preferably 80 to 120°C, and more preferably 94 to 100°C. If the melting point of the polyolefin having acidic groups is 120°C or lower, the rise temperature during heat sealing tends to be lower. If the melting point of the polyolefin having acidic groups is 80°C or higher, it tends to be less prone to blocking in high-temperature environments. From the viewpoint of preventing blocking, it is preferable to have a larger particle size so that the contact area is smaller. Although not particularly limited, the particle size may be 1 nm or larger, 0.1 μm or larger, 0.3 μm or larger, 1 μm or less, 0.7 μm or less, or 0.5 μm or less.

[0082] <Packaging bag> Figure 2 is a perspective view showing a gusset bag 20 made of a laminate 10. The packaging bag is manufactured by sealing the opening at the top of the gusset bag 20. The gusset bag 20 has folded sections (folded sections B1, B2) where the laminate 10 is folded. Folded section B1 is where the laminate 10 is valley-folded when viewed from the innermost layer side, while folded section B2 is where the laminate 10 is mountain-folded when viewed from the innermost layer side.

[0083] The packaging bag may be formed by folding a single laminate in half so that the second resin layers 2 face each other, then folding it appropriately to the desired shape and heat-sealing it, or by stacking two laminates so that the second resin layers 2 face each other and then heat-sealing them to form a bag.

[0084] In the packaging bag according to this embodiment, the heat seal strength may be 2N / 15mm or more, or 4N / 15mm or more. There is no particular upper limit to the heat seal strength, but it may be, for example, 10N / 15mm or less.

[0085] The packaging bag can contain contents such as food and pharmaceuticals. It is particularly suitable for containing confectionery and the like. The packaging bag according to this embodiment can suppress the deterioration of water vapor barrier properties over a long period of time, even though it uses a paper base material and an aluminum vapor-deposited layer.

[0086] In this embodiment, a gusseted bag was given as an example of a packaging bag, but the laminate according to this embodiment may also be used to produce, for example, pillow bags, three-sided sealed bags, or standing pouches. [Examples]

[0087] The present disclosure will be further illustrated by the following examples, but the present disclosure is not limited to these examples. <Fabrication of gas barrier laminates> (Example 1) Clay-coated paper with a clay-coated layer (thickness: 5 μm) (basis weight: 60 g / m²) 2 A sample was prepared in which the dimensional change rate when the temperature was changed from 40°C and relative humidity 20%RH to 40°C and relative humidity 90%RH was CD=0.55% and MD=0.07%. A coating film was formed on the clay coat layer side surface of the clay coat paper by applying Zyxen AC (manufactured by Sumitomo Seika, an aqueous dispersion of ammonium salt of ethylene-acrylic acid copolymer) with a gravure coater. By drying the coating film, a first resin layer (thickness: 3μm, A) was formed on the clay coat layer. COOX / A COOH A first laminate was obtained in which a layer with a thickness of 0.03 was formed. The first laminate was transported using a roll-to-roll vacuum deposition apparatus, and aluminum was deposited onto the surface of the first resin layer to form an aluminum deposition layer. The pressure inside the deposition chamber at this time was 0.05 Pa, and the thickness of the deposition layer was 105 nm. The method for measuring the thickness of the deposition layer will be described later. Next, Chemipearl S300 (manufactured by Mitsui Chemicals, aqueous dispersion of metal salt of ethylene-unsaturated carboxylic acid copolymer, melting point: 96°C) was applied to the aluminum deposition layer using a gravure coater to form a coating film, and the coating film was dried to form a second resin layer (thickness: 3 μm, A COOX / A COOH This formed 1.2), and the laminate of Example 1 was obtained.

[0088] (Example 2) The laminate of Example 2 was obtained in the same manner as in Example 1, except that the material forming the second resin layer was changed to Zyxene AC (manufactured by Sumitomo Seika, an aqueous dispersion of ammonium salt of ethylene-acrylic acid copolymer).

[0089] (Example 3) The laminate of Example 3 was obtained in the same manner as in Example 1, except that the transport speed of the first laminate was slowed to make the thickness of the aluminum deposition layer 120 nm and the pressure inside the deposition chamber was 0.12 Pa during the aluminum deposition process.

[0090] (Example 4) Clay-coated paper with a clay-coated layer (thickness: 5 μm) (basis weight: 60 g / m²) 2 A sample was prepared in which the dimensional change rate when the temperature was changed from 40°C and relative humidity 20%RH to 40°C and relative humidity 90%RH was CD=0.55% and MD=0.07%. An aqueous solution of PVA 5-98 (manufactured by Kuraray, fully saponified PVA, degree of polymerization: 500) was applied to the surface of the clay coat layer of the clay coat paper using a gravure coater to form a coating film. By drying the coating film, a first laminate was obtained in which a first resin layer (thickness: 3 μm) was formed on the clay coat layer. Aluminum was deposited onto the surface of the first resin layer while the first laminate was transported using a roll-to-roll vacuum deposition apparatus to form an aluminum deposition layer. The pressure inside the deposition chamber at this time was 0.09 Pa, and the thickness of the deposition layer was 110 nm. Next, ChemiPearl S300 (manufactured by Mitsui Chemicals, an aqueous dispersion of metal salts of ethylene-unsaturated carboxylic acid copolymers) is applied to the aluminum vapor-deposited layer using a gravure coater to form a coating film, and the coating film is dried to form a second resin layer (thickness: 3 μm, A COOX / A COOH This formed 1.2), and the laminate of Example 4 was obtained.

[0091] (Example 5) Kraft paper (basis weight: 62g / m²) 2A sample was prepared in which the dimensional change rate when the temperature was changed from 40°C and relative humidity 20%RH to 40°C and relative humidity 90%RH was CD=1.11% and MD=0.13%. An aqueous solution of Exceval HR3010 (manufactured by Kuraray; fully saponified ethylene-modified polyvinyl alcohol, degree of polymerization: 1000) was applied to the surface of kraft paper using a gravure coater to form a coating film. By drying the coating film, a first laminate was obtained in which a first resin layer (thickness: 5 μm) was formed on the surface of the kraft paper. Aluminum was deposited onto the surface of the first resin layer while the first laminate was transported using a roll-to-roll vacuum deposition apparatus to form an aluminum deposition layer. The pressure inside the deposition chamber at this time was 0.09 Pa, and the thickness of the deposition layer was 110 nm. Next, ChemiPearl S300 (manufactured by Mitsui Chemicals, an aqueous dispersion of metal salts of ethylene-unsaturated carboxylic acid copolymers) is applied to the aluminum vapor deposition layer using a gravure coater to form a coating film, and the coating film is dried to form a second resin layer (thickness: 2 μm, A COOX / A COOH This formed 1.2), and the laminate of Example 5 was obtained.

[0092] (Example 6) The laminate of Example 6 was obtained in the same manner as in Example 5, except that the material forming the second resin layer was changed to Zyxene AC (manufactured by Sumitomo Seika, an aqueous dispersion of ammonium salt of ethylene-acrylic acid copolymer).

[0093] (Example 7) The laminate of Example 7 was obtained in the same manner as in Example 5, except that the transport speed of the first laminate was slowed to make the thickness of the aluminum deposition layer 180 nm and the pressure inside the deposition chamber was 0.25 Pa during the aluminum deposition process.

[0094] (Example 8) Clay-coated paper with a clay-coated layer (thickness: 5 μm) (basis weight: 60 g / m²) 2A sample was prepared in which the dimensional change rate when the temperature was changed from 40°C and relative humidity 20%RH to 40°C and relative humidity 90%RH was CD=0.35% and MD=0.15%. Takelac WPB-341 (manufactured by Mitsui Chemicals, polyurethane resin emulsion) was applied to the clay coat layer side surface of the clay coat paper using a gravure coater to form a coating film. By drying the coating film, a first laminate was obtained in which a first resin layer (thickness: 2μm) was formed on the clay coat layer. While the first laminate was transported using a roll-to-roll vacuum deposition apparatus, aluminum was deposited on the surface of the first resin layer to form an aluminum deposition layer. The pressure inside the deposition chamber at this time was 0.25 Pa, and the thickness of the deposition layer was 120 nm. Next, Zyxene AC (manufactured by Sumitomo Seika, aqueous dispersion of ammonium salt of ethylene-acrylic acid copolymer) was applied to the aluminum deposition layer using a gravure coater to form a coating film, and by drying the coating film, a second resin layer (thickness: 4μm, A COOX / A COOH This formed a 0.03) layer, and the laminate of Example 8 was obtained.

[0095] (Example 9) The laminate of Example 9 was obtained in the same manner as in Example 8, except that the transport speed of the first laminate was slowed down during aluminum deposition to make the thickness of the aluminum deposition layer 150 nm.

[0096] (Comparative Example 1) A laminate of Comparative Example 1 was obtained in the same manner as in Example 1, except that the transport speed of the first laminate was increased during aluminum deposition to make the thickness of the aluminum deposition layer 60 nm.

[0097] (Comparative Example 2) The laminate of Comparative Example 2 was obtained in the same manner as in Example 2, except that the transport speed of the first laminate was increased during aluminum deposition to make the thickness of the aluminum deposition layer 60 nm.

[0098] (Comparative Example 3) The laminate of Comparative Example 3 was obtained in the same manner as in Comparative Example 1, except that the transport speed of the first laminate was slowed to make the thickness of the aluminum deposition layer 90 nm and the pressure inside the deposition chamber was 0.03 Pa.

[0099] (Comparative Example 4) The laminate of Comparative Example 4 was obtained in the same manner as in Example 4, except that the transport speed of the first laminate was increased to make the thickness of the aluminum deposition layer 60 nm and the pressure inside the deposition chamber was 0.04 Pa.

[0100] (Comparative Example 5) The laminate of Comparative Example 5 was obtained in the same manner as in Example 5, except that the transport speed of the first laminate was increased during aluminum deposition to make the thickness of the aluminum deposition layer 60 nm.

[0101] (Comparative Example 6) The laminate of Comparative Example 6 was obtained in the same manner as in Example 6, except that the transport speed of the first laminate was increased during aluminum deposition to make the thickness of the aluminum deposition layer 60 nm.

[0102] (Comparative Example 7) The laminate of Comparative Example 7 was obtained in the same manner as in Comparative Example 5, except that the transport speed of the first laminate was slowed to make the thickness of the aluminum deposition layer 90 nm and the pressure inside the deposition chamber was 0.03 Pa.

[0103] (Comparative Example 8) The laminate of Comparative Example 8 was obtained in the same manner as in Example 8, except that the transport speed of the first laminate was increased to make the thickness of the aluminum deposition layer 60 nm and the pressure inside the deposition chamber was 0.09 Pa.

[0104] (Comparative Example 9) The laminate of Comparative Example 9 was obtained in the same manner as in Comparative Example 8, except that the transport speed of the first laminate was slowed to make the thickness of the aluminum deposition layer 90 nm and the pressure inside the deposition chamber was 0.03 Pa.

[0105] (Comparative Example 10) Kraft paper (basis weight: 62g / m²) 2 A sample was prepared in which the dimensional change rate when the temperature was changed from 40°C and relative humidity 20%RH to 40°C and relative humidity 90%RH was CD=1.11% and MD=0.13%). 181062PX (MICHELMAN fully saponified PVA aqueous solution) was applied to the surface of kraft paper using a gravure coater to form a coating film. By drying the coating film, a first laminate was obtained in which a first resin layer (thickness: 3μm) was formed on the surface of the kraft paper. While the first laminate was transported using a roll-to-roll vacuum deposition apparatus, aluminum was deposited on the surface of the first resin layer to form an aluminum deposition layer. The pressure in the deposition chamber at this time was 0.15Pa, and the thickness of the deposition layer was 140nm. Next, MC9100 (MICHELMAN ethylene-acrylic acid copolymer resin aqueous dispersion) was applied to the aluminum deposition layer using a gravure coater to form a coating film, and by drying the coating film, a second resin layer (thickness: 3μm, A COOX / A COOH This formed a 0.02) layer, and the laminate of Comparative Example 10 was obtained.

[0106] (Comparative Example 11) Clay-coated paper with a clay-coated layer (thickness: 5 μm) (basis weight: 60 g / m²) 2, a dimensional change rate when changing from a temperature of 40°C and a relative humidity of 20%RH to a temperature of 40°C and a relative humidity of 90%RH was prepared (CD = 0.55%, MD = 0.07%). An aqueous solution of Poval 5-98 (manufactured by Kuraray, fully saponified PVA. Degree of polymerization: 500) was coated on the surface of the clay-coated paper on the clay-coated layer side using a gravure coater to form a coating film. By drying the coating film, a first laminate in which a first resin layer (thickness: 4 μm) was formed on the clay-coated layer was obtained. While transporting the first laminate by a roll-to-roll type vacuum deposition apparatus, aluminum was deposited on the surface of the first resin layer to form an aluminum deposition layer. The pressure in the deposition chamber at this time was 0.40 Pa, and the thickness of the deposition layer was 100 nm. Next, Chem Pearl S500 (manufactured by Mitsui Chemicals, an aqueous dispersion of a metal salt of an ethylene-unsaturated carboxylic acid copolymer) was coated on the aluminum deposition layer using a gravure coater to form a coating film, and by drying the coating film, a second resin layer (thickness: 3 μm, A COOX / A COOH was 1.2) was formed to obtain the laminate of Comparative Example 11.

[0107] <Thickness of aluminum deposition layer> Measurement samples were obtained from the laminates of each example and comparative example. The measurement samples were embedded in a UV-curable resin. The measurement samples were sectioned by cryomicrotome to obtain samples for cross-sectional observation. The obtained samples were observed with a scanning electron microscope (observation magnification: 50,000 times), and images of 10 cross-sections were taken from each sample. The thickness of the aluminum deposition layer was measured from the obtained images. The average value was shown in Tables 1 to 3 as the thickness (nm) of the aluminum deposition layer.

[0108] <X-ray diffraction measurement> The measurement of the half-value width of the peak of the (111) crystal plane of aluminum in the aluminum vapor deposition layer was carried out according to the following procedure. For the measurement of the half-value width, an X-ray diffractometer (trade name: ATX-G) manufactured by Rigaku Corporation was used. CuKα rays were used as the light source, the tube voltage was 50 kV, the tube current was 300 mA, the optical system was a parallel beam optical system, the scanning method was the 2θ / θ method, the measurement range was 30° to 50°, and the scanning speed was 2° / min. Also, the sampling step was 0.02°, and the slits were S1: 10.0 mm × 1.0 mm, S2: 10.0 mm × 0.5 mm, and Sollar (res): 0.4 mm. The laminated bodies obtained in the examples and comparative examples were used as samples, and the paper base material side thereof was attached to a slide glass with double-sided tape for X-ray diffraction measurement. As the X-ray diffraction of aluminum, the half-value width at the peak of 2θ = 38.5° corresponding to the (111) plane (d = 2.34 Å) was measured. The average value of three measurements was used as the half-value width of the diffraction peak at 2θ = 38.5° and is shown in Tables 1 to 3.

[0109] <Measurement of IR Spectrum> Regarding the surfaces of the first resin layer and the second resin layer of the laminated bodies in the examples and comparative examples, an IR spectrum was measured by the ATR method using a Fourier transform infrared spectrophotometer (manufactured by Perkin Elmer, trade name: Frontier). For the peak of the carboxy group that appears with a maximum around 1700 cm -1 the peak area between 1620 and 1770 cm -1 was determined as the area (A COOH ) of the peak derived from the carboxy group. On the other hand, for the peak of the salt of the carboxy group that appears with a maximum around 1540 cm -1 the peak area between 1490 and 1620 cm -1 was determined as the area (A COOX ) of the peak derived from the salt of the carboxy group. From these results, the ratio (A COOX / A COOH ) of the area of the peak derived from the salt of the carboxy group to the area of the peak derived from the carboxy group was calculated. The results are shown in Tables 1 to 3. The measurement of the surface of the first resin layer was carried out on the first laminate before aluminum vapor deposition.

[0110] <Water vapor transmission rate> For the laminates obtained in the examples and comparative examples, the water vapor transmission rate (g / m³) under an atmosphere of 40°C and 90% RH was determined. 2 The water vapor permeability ( / day) was measured using the MOCON method in accordance with JIS K7129-2. A water vapor permeability analyzer (MOCON Corporation, product name: PERMATRAN-W3 / 34G) was used for the measurement. The average of three measurements was used as the initial water vapor permeability, and is shown in Tables 1 to 3. Furthermore, accelerated testing was conducted by storing the laminates of the examples and comparative examples in an environment of 40°C and 90%RH for two months. Storage at 40°C and 90%RH is said to have a 3 to 5 times faster effect than storage at room temperature. The water vapor permeability of the samples after the accelerated testing was measured in the same manner, and the water vapor permeability after the accelerated testing is shown in Tables 1 to 3.

[0111] The laminates of Examples 1 to 9, in which the aluminum vapor deposition layer thickness exceeds 100 nm and the full width at half maximum is between 2.0° and 14.0°, exhibit a water vapor transmission rate of 5 g / m² even after accelerated testing. 2 A good barrier function of less than / day was maintained.

[0112] [Table 1]

[0113] [Table 2]

[0114] [Table 3] [Explanation of Symbols]

[0115] 1...First resin layer, 2...Second resin layer, 3...Paper substrate, 4...Aluminum vapor-deposited layer, 10...Laminate.

Claims

1. A laminate having a structure in which at least a paper substrate, a first resin layer, an aluminum vapor-deposited layer, and a second resin layer are laminated in this order, The thickness of the aluminum vapor deposition layer is greater than 100 nm. A laminate in which the full width at half maximum of the peak of the (111) crystal plane of aluminum in the aluminum vapor-deposited layer, measured by X-ray diffraction, is 2.0° or more and 14.0° or less.

2. The laminate according to claim 1, wherein the second resin layer comprises a polyolefin having an acidic group.

3. The laminate according to claim 1, wherein the first resin layer comprises at least one selected from the group consisting of polyolefins having acidic groups, polyvinyl alcohol-based resins, and polyurethane-based resins.

4. The water vapor transmission rate at a temperature of 40°C and a relative humidity of 90% is 5 g / (m³). ２ The laminate according to claim 1, wherein the number of days is less than or equal to the number of days.

5. The laminate according to claim 1, wherein the second resin layer comprises an ethylene-unsaturated carboxylic acid copolymer.

6. The laminate according to claim 1, wherein the thickness of the aluminum vapor deposition layer is 200 nm or less.

7. The first resin layer comprises a polyolefin having an acidic group, In the IR spectrum of the first resin layer, the carboxyl group originates from 1620–1770 cm⁻¹. －１ The area of ​​the peaks between 1490 and 1620 cm² is derived from the carboxyl group salt. －１ The laminate according to claim 1, wherein the ratio of the areas of the peaks in between is 0.1 or less.

8. In the IR spectrum of the second resin layer, the carboxyl group originates from 1620–1770 cm⁻¹. －１ The area of ​​the peaks between 1490 and 1620 cm² is derived from the carboxyl group salt. －１ The laminate according to claim 2, wherein the ratio of the areas of the peaks in between is 0.1 or less.

9. The first resin layer contains ethylene-modified polyvinyl alcohol, The laminate according to claim 1, wherein the second resin layer comprises a polyolefin having an acidic group.

10. A packaging bag comprising a laminate according to any one of claims 1 to 9.

Images