Complex of hydrotalcite compound and amino acid

Abstract

To provide a composite of a hydrotalcite compound and an amino acid, with the composite having a high aspect ratio while allowing for control of coloration.SOLUTION: The present disclosure relates to a composite that includes a hydrotalcite compound and an amino acid. The composite has an aspect ratio of 85 or more. An Y.I. value of the composite is 0-5. The Y.I. value indicates yellowness. A content of the amino acid in the composite is more than 0 mass% and equal to or less than 10.0 mass%. The content of the amino acid is a content with respect to the total mass of the composite.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a complex of a hydrotalcite compound and an amino acid. [Background technology]

[0002] Hydrotalcite-type compounds, which represent hydrotalcite or its calcined product, have ion exchange ability and are used in a variety of applications, such as suppressing resin degradation by blending them with resins. A method for increasing the aspect ratio of this type of hydrotalcite-type compound using an amino acid is known (Patent Document 1 and Non-Patent Document 1). The methods disclosed in Patent Document 1 and Non-Patent Document 1 allow for the production of a complex of a hydrotalcite-type compound and an amino acid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 092453 [Non-patent literature]

[0004] [Non-Patent Document 1] NATURE COMMUNICATIONS(2019)10:2398, High gas barrier coating using non-toxic nanosheet dispersions for flexible food packaging film. Summary of the Invention [Problem to be solved by the invention]

[0005] However, the methods disclosed in Patent Document 1 and Non-Patent Document 1 mentioned above have the problem that when the aspect ratio of the hydrotalcite-based compound is increased, the compound becomes colored, limiting the applications of the composite.

[0006] Therefore, an object of the present invention is to provide a composite that has greater versatility. [Means for solving the problem]

[0007] As a result of intensive research conducted by the present inventors to achieve the above object, they found that a composite with greater usability can be formed by forming a composite of an amino acid and a hydrotalcite-type compound that has a high aspect ratio and can control colorability. The present disclosure has been completed based on this finding and includes the following aspects.

[0008] (First Disclosure) In the first disclosure, the composite has a hydrotalcite compound and an amino acid. The composite has an aspect ratio of 85 or more. The composite has a YI value of 0 to 5. The YI value indicates yellowness. The composite has an amino acid content greater than 0% by mass and not more than 10.0% by mass. The amino acid content is the content relative to the total mass of the composite.

[0009] (Second Disclosure) The second disclosure is the first disclosure, wherein the amino acid is a glycine-related compound.

[0010] (Third Disclosure) The present third disclosure is the first or second disclosure, wherein the hydrotalcite compound is represented by the following formula (1). (M 2+ ) 1-X (M 3+ ) X (OH)2(A n- ) X / n mH2O (1) (In formula (1), M 2+ is a divalent metal cation. 3+ is a trivalent metal cation. n-is an n-valent anion. In formula (1), X is a number satisfying 0.17 < X < 0.36. In formula (1), n is an integer from 1 to 6. In formula (1), m is a number satisfying 0 < m < 1.80.)

[0011] (Fourth Disclosure) In any one of the first disclosure to the third disclosure, the thickness of the primary particles of the complex is 20 nm or less. The complex has an aspect ratio of 100 or more.)

[0012] (Fifth Disclosure) This fifth disclosure is a coating liquid. The coating liquid contains the complex described in any one of the first disclosure to the fourth disclosure. The coating liquid contains a polymer.)

[0013] (Sixth Disclosure) In this sixth disclosure, in the fifth disclosure, the polymer is a water-soluble polymer.)

[0014] (Seventh Disclosure) In this seventh disclosure, in the sixth disclosure, the water-soluble polymer is polyvinyl alcohol.)

[0015] (Eighth Disclosure) This eighth disclosure is a film. The film has a coating layer.) The coating layer is formed by the coating liquid described in any one of the fifth disclosure to the seventh disclosure.)

[0016] (Ninth Disclosure) In this ninth disclosure, in the eighth disclosure, the thickness of the coating layer is 1 μm or more and 1000 μm or less.) [[ID=4​​​​​​​​

[0018] [Figure 1] FIG. 1 is a schematic diagram of a film manufacturing apparatus for manufacturing a packaging film according to one embodiment of the present invention. [Figure 2] FIG. 2 shows photographs of the slurry solutions after the heating step in Examples 1 to 3 of the present invention and Comparative Examples 1 to 3, and photographs of the slurry solutions when they were heated to 100° C. in the heating step in Comparative Examples 4 to 6. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, a preferred embodiment of the complex of the present invention between a hydrotalcite-type compound and an amino acid (hereinafter, sometimes simply referred to as the "complex of the present invention") will be described in detail. In this specification, the term "complex of the hydrotalcite-type compound and an amino acid" refers to a state in which an amino acid is chemically modified into a hydrotalcite-type compound.

[0020] [Complex] In one embodiment of the present invention, the composite is a composite of a hydrotalcite compound and an amino acid, and has an aspect ratio of 85 or more. The composite of this embodiment has a YI value, which indicates the yellowness index of the composite, of 0 to 5. Furthermore, in the composite of this embodiment, the content of the amino acid relative to the total mass of the composite is more than 0 mass% and 10.0 mass% or less.

[0021] The composite of this embodiment has a high aspect ratio, so that when a coating layer is formed, multiple composites are arranged in the coating layer so as to be parallel to the surface direction of the coating layer, thereby exhibiting excellent gas barrier properties. Furthermore, the composite of this embodiment has a YI value within a specific range of 5 or less and an amino acid content within a specific range of 10.0% by mass or less. This allows the composite of this embodiment to form a highly transparent coating layer that is free from coloration such as yellowish brown. The mechanism of action by which such a highly transparent coating layer is obtained is not limited to any theory, but is thought to be as follows.

[0022] First, the composite of this embodiment can be obtained by a production method including a solution preparation step in which a composite metal oxide obtained by calcining a precursor hydrotalcite-based compound is mixed with an amino acid (e.g., glycine) as a release agent to prepare a slurry solution, and a heating step in which the slurry solution prepared in the solution preparation step is heated. This production method is advantageous in that it produces a hydrotalcite-based compound with thin primary particles because the use of an amino acid as a release agent causes delamination of the hydrotalcite-based compound. However, the heating step for exfoliating the hydrotalcite-based compound promotes peptide bonds between amino acids under alkaline conditions, producing polyamino acids (e.g., peptides such as polyglycine). It is known that peptides such as polyglycine turn yellow as their chains become longer, and the longer the molecular chain, the more yellow they become. Therefore, if a composite of a hydrotalcite-based compound containing such a long-chain peptide (polypeptide) and an amino acid is blended with a polymer or the like in a coating solution, the transparency and aesthetics of the resulting coating layer will be impaired.

[0023] In this embodiment, by setting the slurry concentration and amino acid concentration within specific ranges in the solution preparation process, the formation of peptide bonds between amino acids can be suppressed even under alkaline conditions, thereby inhibiting the production of polyamino acids (peptides). As a result, it is believed that yellowing of the resulting composite can be suppressed. In this way, a composite can be obtained that has a high aspect ratio of 85 or more, a yellowness index (YI) value of 0 to 5, and an amino acid content of more than 0% by mass and 10.0% by mass or less. Such a composite can be blended with a polymer or other component in a coating solution to form a coating layer that combines high gas barrier properties and transparency. Thus, the composite of this embodiment can be used in a wide variety of applications requiring gas barrier properties without sacrificing transparency or aesthetics. For example, when a coating solution containing the composite of this embodiment is applied to a film, high gas barrier properties can be imparted to the film without sacrificing transparency.

[0024] In the composite of this embodiment, the composite metal oxide obtained by calcining a precursor hydrotalcite-based compound in the solution preparation step is hydrated using an aqueous solution of an amino acid. Examples of the aqueous solution of amino acid include an aqueous glycine solution. During hydration, amino acid molecules in the solution are incorporated as anions between the layers of the hydrotalcite-based compound, causing the layers of the hydrotalcite-based compound to peel off. Peeling of the layers of the hydrotalcite-based compound results in the formation of thin particles. The thin particles are heated in a heating step, and a composite is formed as a hydrotalcite-based compound with accelerated particle growth in the width direction. In other words, particles with a high aspect ratio are formed. If the amount of amino acid is too small relative to the amount of hydrotalcite-based compound, insufficient hydrotalcite-based compound particles remain, resulting in a low aspect ratio of the resulting composite. In other words, the composite has an aspect ratio of less than 85.

[0025] As described above, the composite of this embodiment has a YI value, which indicates yellowness, of 0 to 5. This YI value is an index of the "polyamino acid content" that affects coloration such as yellowing. If the YI value exceeds 5, coloration such as yellowish brown occurs, and if such a colored composite is used as a component of a coating liquid to form a coating layer, transparency and aesthetics may be impaired. The YI value is preferably in the range of 4 or less, and more preferably 3 or less. If the YI value is within this range, a coating layer with higher transparency can be formed.

[0026] Hereinafter, various components contained in the composite of this embodiment will be described.

[0027] (Hydrotalcite compounds) The hydrotalcite-based compound contained in the composite of this embodiment is not particularly limited, and examples thereof include hydrotalcite-based compounds represented by the following formula (1). (M 2+ ) 1-X (M3+ ) X (OH)2(A n- ) X / n ·mH2O ···(1) (In formula (1), M 2+ is a divalent metal cation, M 3+ is a trivalent metal cation, and A n- is an n-valent anion. X is a number satisfying 0.17 < X < 0.36. n is an integer from 1 to 6, and m is a number satisfying 0 < m < 1.80.)

[0028] In the above formula (1), preferred M 2+ is Mg 2+ , and preferred M 3+ is Al 3+ . These hydrotalcite compounds have high safety for living bodies, and also have a refractive index close to that of resins such as polypropylene and polyethylene. Therefore, when a coating layer is formed on a substrate made of such a resin, it is easy to maintain transparency. Furthermore, the molar ratio of Mg / Al2 is preferably within the range of 4 to 8 from the viewpoint that a hydrotalcite structure can be more reliably obtained.)

[0029] Also, in the above formula (1), the type of anion of A n- is not particularly limited, and examples include carbonate ions (CO3 2- ) and hydroxide ions (OH - ), etc.)

[0030] Note that the above-mentioned hydrotalcite compounds are the hydrotalcite compounds contained in the composite of this embodiment, but the same applies to the precursor hydrotalcite compounds as raw materials used in the production of the composite of this embodiment. As will be described later, the precursor hydrotalcite compounds are mixed with an aqueous solution of an amino acid after being calcined into a composite metal oxide. The precursor hydrotalcite compounds, that is, the hydrotalcite compounds before calcination, are preferably carbonate ions in terms of not generating corrosive gases such as chlorine gas and nitrogen dioxide gas during calcination.)<​​(amino acid) On the other hand, the amino acids contained in the complex of this embodiment are not particularly limited, and examples thereof include various amino acids such as α-amino acids, β-amino acids, and γ-amino acids. More specific examples include aspartic acid, glutamic acid, asparagine, serine, glycine, β-alanine, β-aminobutyric acid, γ-aminobutyric acid, and β-leucine. These amino acids may contain one type of amino acid alone or two or more types of amino acids. Furthermore, these amino acids may be in the form of a multimer (i.e., a peptide) in which multiple amino acids are bound together.

[0032] Among the various amino acids listed above, the amino acids contained in the complex of this embodiment are preferably amino acids with a solubility of 10 g / 100 mL HO or more, and glycine compounds are particularly preferred. Such amino acids, particularly glycine compounds, have a high dielectric constant, which is advantageous in that a complex with a thin primary particle thickness can be obtained. Furthermore, glycine has bacteriostatic properties and is used in supplements, coloring agents, fragrances, etc., and is also advantageous in terms of biological safety.

[0033] In this specification, substances containing amino acids and amino acid polymers may be referred to as "amino acid compounds." For example, a substance containing glycine and polyglycine may be referred to as a "glycine compound."

[0034] Furthermore, in this specification, "solubility of 10 g / 100 mL H2O or more" means that the mass of the object (i.e., amino acid) that dissolves in 100 g of water at 25°C is 10 g or more.

[0035] In the composite of this embodiment, the content of the amino acid relative to the total mass of the composite is greater than 0% by mass and not more than 10.0% by mass, and is preferably 1.0% by mass to 8.0% by mass, more preferably 1.5% by mass to 6.0% by mass, in order to more reliably form a coating layer that has both high gas barrier properties and transparency.

[0036] Furthermore, as described above, the composite of this embodiment has a high aspect ratio of 85 or more. This allows the composite of this embodiment to exhibit excellent gas barrier properties when a coating layer is formed. The aspect ratio of the composite is preferably 90 or more, and more preferably 100 or more, in order to obtain higher gas barrier properties. The upper limit of the aspect ratio of the composite is not particularly limited, but is, for example, 500 or less.

[0037] In this specification, the aspect ratio of a composite is the ratio of the width (diameter) to the thickness of a primary particle of a composite having a layered structure, and can be determined by dividing the width of the primary particle of the composite by the thickness.

[0038] The thickness of the primary particles of the composite of this embodiment is not particularly limited, and may be, for example, 20 nm or less, as long as it has an aspect ratio of 85 or more. In order to obtain better gas barrier properties when a coating layer is formed on the composite, it is preferable that the thickness of the primary particles of the composite is 20 nm or less and the aspect ratio is 100 or more.

[0039] The thickness of the primary particles of the composite is more preferably within the range of 0.7 nm to 10 nm. When the thickness of the primary particles of the composite is within the range of 0.7 nm to 10 nm, the hydrotalcite compound is sufficiently exfoliated, and when a coating layer is formed, higher gas barrier properties can be exhibited.

[0040] The method for producing the composite of this embodiment will be described below.

[0041] [Method of manufacturing the composite] As described above, the composite of the present embodiment can be obtained by a production method including: a solution preparation step of preparing a slurry solution by mixing an aqueous solution of an amino acid having a predetermined concentration, which serves as a release agent, with a composite metal oxide obtained by calcining a precursor hydrotalcite-type compound; and a heating step of heating the slurry solution obtained in the solution preparation step.

[0042] In the solution preparation step, the amino acid concentration of the slurry solution may be such that the content of the amino acid relative to the total mass of the resulting complex is in the range of more than 0% by mass and not more than 50.0% by mass.

[0043] (Solution preparation process) In the solution preparation step, first, a precursor hydrotalcite-based compound is calcined to obtain a composite metal oxide. The precursor hydrotalcite-based compound may be the same hydrotalcite-based compound as the hydrotalcite-based compound contained in the composite described above. The calcination time for calcining this precursor hydrotalcite-based compound is not particularly limited, but for example, when calcining using a calcination furnace, it is 0.1 hours to 24 hours. Similarly, the calcination temperature is also not particularly limited, but for example, when calcining using a calcination furnace, it is a temperature of 300°C to 700°C. When calcining the precursor hydrotalcite-based compound using microwaves, the calcination time is 1 minute to 12 hours. When calcining using microwaves, the temperature can be, for example, 300°C to 700°C.

[0044] Next, a slurry solution is obtained by adding and mixing a predetermined concentration of an amino acid aqueous solution to the composite metal oxide powder obtained by calcining the precursor hydrotalcite-based compound. In this case, the slurry concentration of the slurry solution is preferably less than 30 g / L. Typically, hydrotalcite-based compounds obtained using such a release agent have thin primary particles with a thickness of only a few nanometers. Therefore, if the slurry concentration is high, gelation occurs during the release process, resulting in a heterogeneous sample. Therefore, in the method for producing a composite of this embodiment, by setting the slurry concentration in the solution preparation step to less than 30 g / L, interparticle interactions of the hydrotalcite-based compound can be reduced and gelation during the release process can be suppressed. This allows the above production method to maintain the slurry state of the slurry solution, thereby enabling uniform and efficient production of composites.

[0045] It is more preferable that the slurry concentration in the solution preparation step is within the range of 10 g / L to 28 g / L in terms of productivity, etc. Here, the slurry concentration can be calculated by the following formula. Slurry concentration (g / L) = weight of composite metal oxide (g) / volume of slurry (L)

[0046] In the solution preparation step, the amino acid concentration of the slurry solution is preferably less than 0.6 mol / L. When the amino acid concentration of the slurry solution is within this range, a composite having an aspect ratio of 85 or more and a YI value of 0 to 5 can be more reliably obtained. In other words, a composite having high gas barrier properties and capable of forming a highly transparent coating layer free of coloration such as yellowish brown can be more reliably obtained. It is more preferable that the amino acid concentration of the slurry solution is within the range of 0.2 mol / L to 0.5 mol / L.

[0047] In the solution preparation step, the molar ratio of the amino acid in the slurry solution to the trivalent metal cation of the hydrotalcite-based compound, i.e., amino acid / (M 3+ The molar ratio of 2 to 6 is preferably in the range of 2 to 6. For example, when the amino acid is glycine and the trivalent metal cation of the hydrotalcite compound is Al 3+ In this case, the molar ratio of glycine / Al2 is preferably within a range of 2 to 6. When the molar ratio is within this range, it is possible to more reliably obtain a composite having an aspect ratio of 85 or more and a YI value of 0 to 5, that is, a composite that has high gas barrier properties and is capable of forming a highly transparent coating layer that is free from coloration such as yellowish brown.

[0048] (Heating process) In the heating step, the slurry solution obtained in the solution preparation step is heated to promote particle growth of the hydrotalcite-based compound. At this time, amino acid molecules in the solution are incorporated as anions between the layers of the hydrotalcite-based compound, causing the layers of the hydrotalcite-based compound to peel off, and complexes of the hydrotalcite-based compound and amino acids are produced as thin particles (i.e., particles with a high aspect ratio).

[0049] In the heating step, it is preferable to heat the slurry solution while stirring it. The stirring means is not particularly limited, but it is preferable to use a means that can stir the slurry solution uniformly while maintaining its fluidity.

[0050] In the heating step, the heating temperature is not particularly limited, but is preferably within the range of 20°C to 250°C, and from the viewpoint of more reliably suppressing denaturation of the amino acids, the upper limit of the heating temperature is particularly preferably 170°C. The heating time is not particularly limited, but is preferably within the range of 1 minute to 100 hours. In addition, the heating step is preferably carried out in a closed system, from the viewpoint of preventing fluctuations in the concentration of the slurry solution.

[0051] (Other processes) The steps after the heating step are not particularly limited as long as they do not impair the effects of the present invention. Examples of the steps after the heating step include a washing step in which the slurry solution after the heating step is washed with an alkaline solution (e.g., a sodium hydroxide solution), a solid-liquid separation step in which a solid is obtained by performing a solid-liquid separation treatment after the washing step, a drying step in which the solid obtained in the solid-liquid separation step is dried to obtain a powder of the composite, and a surface treatment step in which the surfaces of the composite particles are treated with various surface treatment agents.

[0052] Examples of surface treatment agents used in the surface treatment step include, but are not limited to, anionic surfactants, cationic surfactants, phosphate ester treatment agents, silane coupling agents, titanate coupling agents, aluminum coupling agents, silicone treatment agents, silicic acid, and water glass. Particularly preferred surface treatment agents are one or more selected from the group consisting of oleic acid, stearic acid, octanoic acid, and octylic acid. Surface treatment of the composite particles can prevent aggregation of primary particles when they are added to, kneaded with, or dispersed in a resin.

[0053] Furthermore, before the above-mentioned washing step, a dilution step of diluting the slurry after the heating step with ion-exchanged water may be carried out, and instead of the above-mentioned drying step, a coating liquid preparation step of preparing a coating liquid by mixing the slurry with a polymer solution or the like may be carried out.

[0054] The composite of this embodiment obtained by the above production method can be mixed with a polymer solution to prepare a coating liquid, as described above.

[0055] [Coating fluid] A coating liquid containing the composite of this embodiment and a polymer can be applied to a substrate described below and dried to form a coating layer. The concentration of the composite contained in the coating liquid is not particularly limited, but from the viewpoint of coatability onto the substrate, a concentration of 20% by mass or less is preferred, and a concentration of 10% by mass or less is more preferred.

[0056] (polymer) The polymer contained in the coating liquid is used in the form of a solution dissolved in a solvent such as water, alcohol, etc. The polymer concentration in the solution is not particularly limited, but from the viewpoint of coatability onto a substrate, a concentration of 20% by mass or less is preferred, and a concentration of 10% by mass or less is more preferred.

[0057] The type of polymer contained in the coating solution is not particularly limited, and any polymer can be used depending on the application of the coating layer or film to be formed. Examples of such polymers include water-soluble polymers, and more specifically, polyvinyl alcohol, copolymers containing vinyl alcohol (e.g., polyethylene vinyl alcohol), carboxymethyl cellulose, polyacrylic acid, polyacrylamide, and the like. These water-soluble polymers may be used alone or in combination with two or more polymers. The use of water-soluble polymers facilitates separation of the substrate and coating layer, increasing recyclability and contributing to the achievement of the Sustainable Development Goals (SDGs) adopted at the United Nations Summit.

[0058] Among these water-soluble polymers, polyvinyl alcohol is preferably used in terms of gas barrier properties, transparency, and coatability.

[0059] (Other ingredients) The coating liquid may contain other additive components in addition to the above-described composite and polymer, as long as the effects of the present invention are not impaired. Examples of such additive components include, but are not limited to, antioxidants, reinforcing agents, UV absorbers, pigments, crosslinking agents, and flame retardants. These additive components may be used alone or in combination of two or more.

[0060] [film] A coating liquid containing the composite of this embodiment and a polymer can be applied to a substrate and dried to form a coating layer. Drying conditions can be appropriately set, for example, at a temperature ranging from room temperature to 160°C for 1 second to 24 hours. When a film-like substrate (hereinafter sometimes referred to as a "film-like substrate") is used as the substrate, a multilayer film can be obtained in which the film-like substrate is covered with a coating layer. Alternatively, a single-layer film consisting of the coating layer can be obtained by peeling off the coating layer from the substrate. The multilayer or single-layer film thus obtained can be suitably used, for example, as various packaging films.

[0061] When a water-soluble polymer is used, the packaging film may be formed as a multi-layer structure of the water-soluble polymer or as a single-layer structure of the water-soluble polymer. Examples of such packaging films include films for packaging detergents, pesticides, or pharmaceutical agents. The agent may be in the form of, for example, a powder, solid, gel, or liquid. The packaging film may also be used as a film for packaging fish bait. Furthermore, the packaging film may also be used as a film for packaging liquid detergents.

[0062] (base material) The substrate used to form the film is not particularly limited, and any substrate can be used depending on the application of the film to be formed, etc. Examples of such substrates include the film-like substrates described above, and more specific examples include resin films such as polyolefin films such as polyethylene and polypropylene, and polyester films such as polyethylene terephthalate; paper; and fiber sheets such as woven fabric, nonwoven fabric, and knitted fabric.

[0063] When a film-like substrate is used as the substrate, its thickness is not particularly limited, but is preferably, for example, 0.01 μm to 250 μm, and more preferably, within the range of 1 μm to 100 μm. The thickness of the coating layer formed by the above-mentioned coating liquid is also not particularly limited, but is, for example, within the range of 0.01 μm to 100 μm.

[0064] Films obtained using the composite of the present invention can be used in a wide range of fields, such as food packaging films, beverage packaging films, beverage bottles, pharmaceutical packaging films, industrial gas barrier films, gas separation films, and paper barrier materials.

[0065] Furthermore, a film containing the composite of the present invention can be used for a bag-shaped package. The package can be an individual package, an inner package, an outer package, or any other structure depending on the packaged item to be placed inside.

[0066] When a film containing the composite of the present invention is used in a bag-shaped package, the bag-shaped package can be configured, for example, to have a coating layer on the outside of the package. The coating layer can be formed by applying a coating liquid containing the composite to the outside of the package and drying it. The package can be configured to have a high aspect ratio, improving gas barrier properties, while also having controlled colorability. In particular, by having a coating layer formed from a coating liquid on the outside of the package, for example, the package can prevent leaching of coating components even when the packaged object is liquid or contains a liquid.

[0067] Furthermore, when a film containing the composite of the present invention is used in a bag-shaped package, the bag-shaped package can be configured to have, for example, a coating layer on the inside of the package. The coating layer can be formed by applying a coating liquid containing the composite to the inside of the package and drying it. For example, by having a coating layer formed by a coating liquid on the inside of the package, the coating layer can be maintained without being damaged even when the package is subjected to external influences such as friction or water wetting. As a result, the package can maintain the effects of the coating layer, such as gas barrier properties, and therefore the quality of the contents. Note that, for example, when the bag-shaped package is configured to have a coating layer on the inside of the package, the coating layer may be formed on the fused surface of the package. Furthermore, when the bag-shaped package is configured to have a coating layer on the inside of the package, for example, an adhesive layer with gas barrier properties may be formed on the fused surface of the package, and the coating layer may be formed on the fused surface of the package, excluding the adhesive layer.

[0068] Furthermore, when a film containing the composite of the present invention is used in a bag-shaped package, the bag-shaped package can be configured, for example, to have a coating layer on both the inside and outside of the package. By having a coating layer formed by a coating liquid on both the inside and outside of the package, the bag-shaped package can achieve higher gas barrier properties than when a coating layer is provided on only one side of the package. As a result, the bag-shaped package can maintain the quality and long-term storage of contents with low water activity, such as flour, confectioneries, tea leaves, and dried vegetables.

[0069] A film containing the composite of the present invention may be formed into a multilayer film structure having a coating layer formed by a coating liquid between film-like substrates. When a multilayer film containing the composite of the present invention is used in a bag-like package, the bag-like package may be configured, for example, with a pair of multilayer films so that the packaged object can be stored inside. A bag-like package using a multilayer film containing the composite can be configured without the need to use a separate adhesive because the film-like substrates can be bonded together. A bag-like package using a multilayer film can combine the advantages of a bag-like package having a coating layer formed by a coating liquid on the outside of the package and a bag-like package having a coating layer formed by a coating liquid on the inside of the package.

[0070] When the film containing the complex has a single layer structure, the coating layer itself becomes the film. A film with a single layer structure can be produced, for example, by a film production apparatus 100 shown in FIG.

[0071] The film production apparatus 100 includes a first tank 1, a second tank 2, and a third tank 3. The film production apparatus 100 also includes a first coating drum 71, a second coating drum 72, and a casting belt 8. In the film production apparatus 100, the first coating drum 71 and the second coating drum 72 rotate, causing the casting belt 8 to move between them. In other words, the casting belt 8 can move between them by the rotation of the first coating drum 71 and the second coating drum 72. In the film production apparatus 100, a drying device 9 capable of blowing hot air 10 is disposed opposite the casting belt 8 moving between the first coating drum 71 and the second coating drum 72. In FIG. 1, the hot air 10 is illustrated by a dashed line.

[0072] A first tank 1 in FIG. 1 stores a slurry containing a complex and water. The first tank 1 is provided with a first agitator 41 that agitates the slurry. A second tank 2 stores a polymer. The second tank 2 is provided with a second agitator 42 that agitates the polymer. The first tank 1 is configured to supply the slurry to a third tank 3 via a first pump 51. The second tank 2 is configured to supply the polymer to the third tank 3 via a second pump 52. The third tank 3 is provided with a third agitator 43 that agitates a mixed polymer obtained by mixing the slurry supplied from the first tank 1 and the polymer supplied from the second tank 2.

[0073] The third tank 3 casts the mixed polymer from the casting die 6 onto the casting belt 8 via the third pump 53. The mixed polymer cast from the casting die 6 moves in the traveling direction together with the casting belt 8, and is arranged in the width direction and traveling direction of the casting belt 8. The mixed polymer moving in the traveling direction together with the casting belt 8 is dried by hot air 10 from a drying device 9 to become a film 12. In FIG. 1, the arrow parallel to the casting belt 8 indicates the traveling direction of the casting belt 8.

[0074] The film manufacturing apparatus 100 is provided with a peeling roll 11 adjacent to the second coating drum 72, which peels off the film 12 on the casting belt 8. The film manufacturing apparatus 100 is provided with a winding device 13 corresponding to the peeling roll 11. The winding device 13 winds up the film 12 peeled off by the peeling roll 11. In FIG. 1, an arrow parallel to the film 12 peeled off by the peeling roll 11 indicates the traveling direction of the film 12.

[0075] The film manufacturing apparatus 100 may use, for example, a plated roll as a support instead of the casting belt 8. The film is not limited to being formed using the solution casting method, but may also be formed using a melt extrusion method.

[0076] The packaging film using the coating layer containing the composite of this embodiment can be turned into a bag-shaped package containing the contents inside by sealing the edges of the film together using, for example, a heated seal bar. The film can be sealed by, for example, heat sealing, water sealing, or glue sealing.

[0077] The packaging film can seal and package, for example, a single dose of liquid detergent. When polyvinyl alcohol is used as the coating layer, the bag-shaped bag becomes a water-soluble bag-shaped bag. The bag-shaped bag has water solubility derived from polyvinyl alcohol, and by further containing the composite of this embodiment, it can maintain high aroma retention. Furthermore, by containing the composite, the bag-shaped bag can be made thinner while maintaining its strength. In the case of a water-soluble bag-shaped bag-shaped bag, the film thickness is preferably 1 μm or more, more preferably 10 μm or more. In the case of a water-soluble bag-shaped bag-shaped bag-shaped bag, the film thickness is preferably 1000 μm or less, more preferably 500 μm or less. The film thickness can be measured, for example, with a micrometer or a film thickness meter using optical interferometry.

[0078] The coating liquid may contain at least one auxiliary agent, such as a surfactant, a plasticizer, a release agent, a stabilizer, a colorant, an ultraviolet absorber, an extender, an antifoaming agent, or a dispersant. The auxiliary agent may be either an organic substance or an inorganic substance.

[0079] Examples of surfactants include ionic surfactants, nonionic surfactants, and polymer surfactants. Examples of ionic surfactants include anionic surfactants, cationic surfactants, and amphoteric surfactants. The content of the surfactant is not particularly limited, but is preferably 0.03 parts by mass or more, and more preferably 0.05 parts by mass or more, per 100 parts by mass of the polymer. The content of the surfactant is preferably 2.5 parts by mass or less, and more preferably 1.5 parts by mass or less, per 100 parts by mass of the polymer.

[0080] Examples of the plasticizer include glycerin, diglycerin, glucose, fructose, lactose, sorbitol, mannitol, ethylene glycol, propylene glycol, and trimethylolpropane.

[0081] The coating liquid may contain inorganic particles in addition to the complex having a hydrotalcite compound and an amino acid. Examples of the inorganic particles in addition to the complex include silica, talc, kaolin, mica, graphite, calcium sulfate, magnesium oxide, and magnesium hydroxide.

[0082] [Examples of applications other than film] Furthermore, the complex of the present invention can be used as an additive to be added to cosmetics. In other words, one aspect of the present invention is a cosmetic comprising the complex of the present invention. The complex inhibits the permeation of specific molecules such as oxygen and moisture. Therefore, cosmetics comprising the complex can control the permeability of specific molecules such as oxygen and moisture by adjusting the content of the complex. The complex exhibits a specific yellowness and reflects light. Therefore, cosmetics comprising the complex can be obtained that allow for control of light reflection properties.

[0083] Furthermore, the composite of the present invention can be used as an additive to be added to paint. In other words, one aspect of the present invention is a paint containing the composite of the present invention. The composite suppresses the permeation of specific molecules such as oxygen and water vapor. Therefore, by adjusting the content of the composite, the permeability of specific molecules such as oxygen and water vapor in a paint containing the composite can be controlled. The composite has flame retardancy due to the hydrotalcite compound. Therefore, by making a paint containing the composite, a paint capable of suppressing combustion can be obtained. Furthermore, the composite exhibits a specific yellowness and reflects light. Therefore, by making a paint containing the composite, a paint capable of controlling the light reflection characteristics can be obtained.

[0084] Furthermore, the composite of the present invention can be used as a resin additive to be added to a resin. One aspect of the present invention is a resin composition containing the composite of the present invention. A resin composition containing the composite as a resin additive can have increased strength compared to a resin composition that does not contain the composite. In other words, by using the composite as a resin additive, a resin composition having a reinforcing effect due to a high aspect ratio can be obtained. Furthermore, a resin composition containing the composite as a resin additive can be colored a predetermined color corresponding to the yellowness of the composite, depending on the content of the composite.

[0085] Furthermore, a resin composition containing the composite of the present invention can be molded according to the appropriate application. For example, it can be molded into a tube by extrusion molding. In other words, one aspect of the present invention is a tube containing the composite of the present invention. The composite suppresses the permeation of inert gases such as helium gas, and special molecules such as oxygen and moisture. Therefore, by adjusting the content of the composite, the permeability of a tube containing the composite to inert gases such as helium gas, and special molecules such as oxygen and moisture can be controlled. For example, a tube obtained by blending the composite of the present invention with a highly biocompatible resin can be used as various tubes required for use in the medical field, such as those with gas barrier properties. An example of such a tube is a medical catheter.

[0086] The present invention is not limited to the above-described embodiments or the examples to be described later, and appropriate combinations, substitutions, modifications, etc. are possible within the scope that does not deviate from the object and intent of the present invention. [Example]

[0087] EXAMPLES The present invention will be explained in more detail below by way of examples and comparative examples, but the present invention is not limited to these examples.

[0088] Example 1 (Production of precursor hydrotalcite compounds) Deionized water was placed in a 1 L reaction vessel, and while stirring, 160 mL of 1.5 mol / L magnesium chloride aqueous solution, 120 mL of 1 mol / L aluminum chloride aqueous solution, and a mixed solution of 90 mL of 8 mol / L sodium hydroxide aqueous solution and 60 mL of 1 mol / L sodium carbonate aqueous solution were simultaneously added dropwise to obtain a reaction product. The pH during the reaction was 9.5. The resulting reaction product was washed with water, and then deionized water was added to obtain 700 mL of re-emulsified slurry. The resulting re-emulsified slurry was subjected to hydrothermal treatment at 170°C for 13 hours. The resulting solid was then washed with water, dried at 105°C for 16 hours, and pulverized. The chemical formula of the resulting powder was Mg 0.67 Al 0.33 (OH)2(CO3) 0.17 This hydrotalcite-type compound was used as a precursor hydrotalcite-type compound to produce the composite.

[0089] (Caking of precursor hydrotalcite compounds) The obtained precursor hydrotalcite compound was calcined in an electric furnace at 450°C for 12 hours to obtain a calcined product (composite metal oxide).

[0090] (Solution preparation process) 17.5 g of the resulting fired material was placed in a glass beaker, and 175 mL of a 2 mol / L glycine aqueous solution (equivalent to 26.3 g of glycine powder) was added and stirred until homogenous. At this time, the glycine / Al2 molar ratio of the resulting slurry solution was 5.26. Ion-exchanged water was then added to bring the total volume to 700 mL, and the mixture was stirred again until homogenous. The slurry concentration at this time was 25 g / L. The glycine concentration at this time was 0.5 mol / L.

[0091] (Heating process) Next, the slurry solution was subjected to hydrothermal treatment at 100°C for 48 hours while stirring at 700 rpm. The obtained sample (slurry solution) was a white slurry with no particular odor. A photograph of the slurry solution after the heating process is shown in Figure 2.

[0092] (Washing process - Drying process) Next, ion-exchanged water was added to the resulting slurry solution to make the total volume 1750 mL, and the mixture was stirred at room temperature at 400 rpm for 16 hours using a stirrer. While stirring the slurry solution, 88.4 mL of a 3.96 mol / L aqueous sodium hydroxide solution was gradually added dropwise to the slurry solution. The resulting slurry solution was subjected to solid-liquid separation to obtain a solid. The resulting solid was then dried at 60°C for 16 hours to obtain a sample (composite) of Example 1. The characteristics of the resulting sample are shown in Table 1 below.

[0093] Example 2 A sample of Example 2 was obtained in the same manner as in Example 1, except that 14.0 g of the fired product and 140 mL of a 2 mol / L glycine aqueous solution (equivalent to 21.0 g of glycine powder) were used in the solution preparation step. The slurry concentration of the slurry solution in the solution preparation step was 20 g / L, and the glycine concentration was 0.4 mol / L.

[0094] Example 3 A sample of Example 3 was obtained in the same manner as in Example 1, except that 7.0 g of the fired product and 70 mL of a 2 mol / L glycine aqueous solution (equivalent to 10.5 g of glycine powder) were used in the solution preparation step. The slurry concentration of the slurry solution in the solution preparation step was 10 g / L, and the glycine concentration was 0.2 mol / L.

[0095] Comparative Example 1 A sample of Comparative Example 1 was obtained in the same manner as in Example 1, except that 70.0 g of the fired product was used in the solution preparation step, 700 mL of a 2 mol / L glycine aqueous solution (equivalent to 105.1 g of glycine powder) was used, and stirring was not performed in the heating step. The slurry concentration of the slurry solution in the solution preparation step was 100 g / L, and the glycine concentration was 2 mol / L.

[0096] Comparative Example 2 A sample of Comparative Example 2 was obtained in the same manner as in Example 1, except that 70.0 g of the fired product was used in the solution preparation step, 266 mL of a 2 mol / L glycine aqueous solution (equivalent to 39.9 g of glycine powder) was used, and stirring was not performed in the heating step. The slurry concentration of the slurry solution in the solution preparation step was 100 g / L, and the glycine concentration was 0.76 mol / L.

[0097] Comparative Example 3 A sample of Comparative Example 3 was obtained in the same manner as in Example 1, except that 70.0 g of the fired product was used in the solution preparation step, no glycine aqueous solution was used, stirring was not performed in the heating step, and the washing step was not performed. The slurry concentration of the slurry solution in the solution preparation step was 100 g / L, and the glycine concentration was 0 mol / L.

[0098] Comparative Example 4 A sample of Comparative Example 4 was obtained in the same manner as in Example 1, except that 35.0 g of the fired product and 350 mL of a 2 mol / L glycine aqueous solution (equivalent to 52.5 g of glycine powder) were used in the solution preparation step. The slurry concentration of the slurry solution in the solution preparation step was 50 g / L, and the glycine concentration was 1 mol / L.

[0099] Comparative Example 5 A sample of Comparative Example 5 was obtained in the same manner as in Example 1, except that 28.0 g of the fired product and 280 mL of a 2 mol / L glycine aqueous solution (equivalent to 42.0 g of glycine powder) were used in the solution preparation step. The slurry concentration of the slurry solution in the solution preparation step was 40 g / L, and the glycine concentration was 0.8 mol / L.

[0100] Comparative Example 6 A sample of Comparative Example 6 was obtained in the same manner as in Example 1, except that 21.0 g of the fired product and 210 mL of a 2 mol / L glycine aqueous solution (equivalent to 31.5 g of glycine powder) were used in the solution preparation step. The slurry concentration of the slurry solution in the solution preparation step was 30 g / L, and the glycine concentration was 0.6 mol / L.

[0101] Example 4 (Preparation of coating liquid) The solids concentrations of the sample of Example 1 and an aqueous polyvinyl alcohol (PVA) solution (Sigma-Aldrich Corporation, Mw 67,000, Mowiol (registered trademark) 8-88) were measured, and ion-exchanged water was added to adjust the concentration so that the complex of the hydrotalcite type compound and the glycine type compound of Example 1 was 3 wt % and the PVA was 2 wt %, and this was mixed while stirring to obtain a coating liquid.

[0102] (Film Preparation) First, a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., Lumirror (registered trademark), film thickness 50 μm, product number type #50-U483) cut to a length of 55 mm and a width of 105 mm was fixed onto the glass plate of an automatic coating device (manufactured by Tester Sangyo Co., Ltd., PI-1210 type). Next, a baker applicator (manufactured by Yoshimitsu Seiki Co., Ltd., YBA type) was set on the glass plate of the automatic coating device, and the coating liquid was applied onto the PET film to a uniform thickness of 50 μm. The coating layer formed by the applied coating liquid was dried at room temperature for 16 hours to obtain the film of Example 4.

[0103] Comparative Example 7 A film of Comparative Example 7 was obtained in the same manner as in Example 4, except that the sample of Comparative Example 1 was used instead of the sample of Example 1.

[0104] Comparative Example 8 The film of Comparative Example 8 was obtained in the same manner as in Example 4, except that the precursor hydrotalcite compound obtained in the "production of precursor hydrotalcite compound" step of Example 1 was used instead of the sample of Example 1 (complex of hydrotalcite compound and glycine compound). That is, the film of Comparative Example 8 was obtained using an unexfoliated hydrotalcite compound (unexfoliated HT) instead of the complex of hydrotalcite compound and glycine compound.

[0105] Comparative Example 9 The film of Comparative Example 9 was obtained in the same manner as in Example 4, except that no coating liquid was applied. That is, the film of Comparative Example 9 is a PET film (film-like substrate) alone on which no coating layer made of a coating liquid is formed.

[0106] Comparative Example 10 A film of Comparative Example 10 was obtained in the same manner as in Example 4, except that a coating liquid containing only PVA was used.

[0107] Example 5 (Film Preparation) The film of Example 5 was obtained in the same manner as in Example 4, except that a polypropylene (PP) film (manufactured by Toyobo Co., Ltd., Pylen (registered trademark) Film-OT, film thickness 50 μm, brand P2261) was used as the film-like substrate and the coating liquid was applied so as to achieve a uniform thickness of 25 μm.

[0108] Example 6 A film of Example 6 was obtained in the same manner as in Example 5, except that the coating liquid was applied so as to give a uniform thickness of 12.5 μm.

[0109] Comparative Example 11 The film of Comparative Example 11 was obtained in the same manner as in Example 5, except that no coating liquid was applied. That is, the film of Comparative Example 11 was a PP film (film-like substrate) alone on which no coating layer made of a coating liquid was formed.

[0110] Comparative Example 12 A film of Comparative Example 12 was obtained in the same manner as in Example 5, except that a coating liquid containing only PVA was used.

[0111] [Various measurements] Measurements of various physical properties, etc. shown below were carried out for the samples of Examples 1 to 3 and Comparative Examples 1 to 6. The measurement results are shown in Table 1 below. Photographs were also taken of the slurry solutions of Examples 1 to 3 and Comparative Examples 1 to 3 after the heating step, and of the slurry solutions of Comparative Examples 4 to 6 when they were heated to 100°C in the heating step. These photographs are shown in FIG. 2.

[0112] (Viscosity measurement after heating process) The temperature of the slurry solution was adjusted to 25°C, and then the viscosity was measured at the same temperature using a B-type viscometer (Brookfield, DV2T model).

[0113] (Measurement of thickness and aspect ratio of primary particles of composite) The width and thickness of the primary particles were measured using a scanning probe microscope (Shimadzu Corporation, SPM-9700HT model). The aspect ratio was calculated using the following formula. (Aspect ratio of primary particle) = (Width of primary particle) / (Thickness of primary particle) The aspect ratio was calculated for each of 20 randomly selected primary particles, and the average value was used as the aspect ratio of the sample.

[0114] (Measurement of glycine compound content) 0.5 g of powder sample dried at 60°C for 16 hours, 5 g of potassium sulfate, and 2 g of copper(II) sulfate pentahydrate were thoroughly mixed and placed in a sample tube, followed by the addition of 15 mL of concentrated sulfuric acid. The mixture was then treated at 470°C for 90 minutes using a Kjeldahl analysis system (Buchi, KjelFlex K-360 / K-425 SpeedDigester). Steam distillation was then performed for 240 seconds using 10 mL of ion-exchanged water, 30% aqueous sodium hydroxide, and 40 mL of 2% aqueous boric acid. Three drops of a mixed indicator of methyl red and methylene blue were added to the resulting distillate, which was then titrated with 0.1 mol / L aqueous hydrochloric acid until the distillate turned purple. A blank sample without the powder sample was also titrated in the same manner, and the content of glycine compounds was calculated using the following formulas (I) and (II). (Nitrogen content) [wt%] = ((factor of 0.1 mol / L hydrochloric acid solution) × (drop amount [ml] - blank [ml]) × 1.401 [mg / ml]) × 100 / powder sample amount [mg] (I) (Glycine compound content)[wt%]=(Nitrogen N content)[wt%]×(75.07[g / mol] / 14.01[g / mol])...(II)

[0115] (Yellowness index (YI value) measurement) The powder sample was dried at 60°C for 16 hours, pulverized, and sieved through a 150 μm mesh screen. 0.2 g of the powder was then placed in a glass reagent bottle. Measurements were then performed using a 10-diameter observation glass and sample stage with a colorimeter (Nippon Denshoku Industries Co., Ltd., Color Meter ZE6000) that had been pre-calibrated against a standard white board. A total of three measurements were performed, with the reagent bottle being shaken 10 times before each measurement. The average of the three measurements was calculated to obtain the Yellow Index (YI) value.

[0116] [Film Rating] The following physical properties and the like were measured for the films of Examples 4 to 6 and Comparative Examples 7 to 12. The measurement results are shown in Tables 2 and 3 below.

[0117] (Total light transmittance and haze measurement) The film was cut 20 mm from the coating end point, and the coated surface was placed on the incident light side and measured with a haze meter (NDH4000 model, manufactured by Nippon Denshoku Industries Co., Ltd.) to obtain total light transmittance and haze.

[0118] (Oxygen gas permeability measurement) The film was cut into a circle with a diameter of approximately 55 mm, and the gas permeability was measured using a gas permeability measuring device (GTR-11AET model, manufactured by GTR Tech Co., Ltd.) according to JIS K 7126-1 Part 1 (differential pressure method) under the following conditions. ·Measurement temperature: 23.0℃ Relative humidity: zero ·Transmission area: 15.2cm 2 Measurement gas: Oxygen gas The oxygen gas that permeated the film was analyzed using a capillary gas chromatograph system (Shimadzu Corporation, GC-2014 model) to obtain the oxygen gas permeability. Note that the measurement analysis time for oxygen gas permeability measurement can be adjusted appropriately depending on the gas permeability of the film.

[0119] [Table 1]

[0120] [Table 2]

[0121] [Table 3]

[0122] As shown in Tables 1 to 3 and Fig. 2, the composites of hydrotalcite compounds and glycine compounds in the examples of the present invention were able to form films (coating layers) that had both high gas barrier properties and transparency. On the other hand, the composites in the comparative examples were colored yellowish brown or gelled, and were unable to form films that had both high gas barrier properties and transparency like those of the present invention. [Industrial Applicability]

[0123] The composite of the present invention, a coating liquid containing the composite, and a film having a coating layer formed using the coating liquid can be used, for example, as a food packaging film, a beverage packaging film, a beverage bottle, a pharmaceutical packaging film, an industrial gas barrier film, a gas separation film, etc. Furthermore, the composite of the present invention and a coating liquid containing the composite can be suitably used in a wide range of fields, such as paper barrier materials, paints, scratch-resistant materials, cosmetics, and additives. [Explanation of symbols]

[0124] 100 Film manufacturing equipment 1. First Tank 2. Second Tank 3. Third Tank 41 First mixer 42 Second agitator 43 Third Mixer 51 First Pump 52 Second Pump 53 Third Pump 6 Casting die 71 No. 1 coating drum 72 No. 2 coating drum 8 Casting Belt 9 Drying equipment 10 hot air 11 Peeling roll 12 Film 13 Winding device

Claims

1. A composite of a hydrotalcite compound and an amino acid, having an aspect ratio of 85 or more, the amino acid is a glycine-based compound, the glycine compound includes glycine and polyglycine, The hydrotalcite compound is represented by the following formula (1): The composite has a YI value indicating a yellowness index of 0 to 5, A complex, characterized in that the content of the amino acid relative to the total mass of the complex is greater than 0 mass% and 10.0 mass% or less. (M 2+ ) 1-X (M 3+ ) X (OH) 2 (A n- ) X / n ・mH 2 O ... (1) (In formula (1), M 2+ is a divalent metal cation, M 3+ is a trivalent metal cation, A n- is an n-valent anion, X is a number that satisfies 0.17<X<0.36, n is an integer from 1 to 6, and m is a number that satisfies 0<m<1.80.)

2. The complex described in claim 1, wherein the aspect ratio of the complex is 500 or less.

3. The composite according to claim 1 , wherein the thickness of the primary particle is 20 nm or less, and the aspect ratio is 100 or more.

4. A coating liquid comprising the composite of claim 1 and a polymer.

5. The coating liquid according to claim 4, wherein the polymer is a water-soluble polymer.

6. The coating liquid according to claim 5, wherein the water-soluble polymer is polyvinyl alcohol.

7. A film having a coating layer formed from the coating liquid according to claim 4.

8. 8. The film according to claim 7, wherein the thickness of the coating layer is 1 μm or more and 1000 μm or less.

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