Hydrotalcite compound, method for producing same, and resin film containing same

Abstract

This hydrotalcite compound is represented by formula (I): [M12+ 1-xM23+ x(OH)2][(A1n-)x / n·mH2O] ··· (I) [In formula (I), M12+ denotes one or more divalent metal ions, M23+ denotes one or more trivalent metal ions, A1n- denotes one or more anions having a valency of n, said one or more anions having a valency of n includes at least an anionic organic dye having absorption at a wavelength of 450 nm or more, the value of m is not less than 0 but less than 1, the value of n is 1-5, and the value of x is more than 0 but less than 0.5.]　The anion further includes a carbonate ion and a nitrate ion. The hydrotalcite compound is surface treated with a higher fatty acid.

Description

Hydrotalcite compound, its production method, and resin film containing the same

[0001] The present disclosure relates to a hydrotalcite compound, a method for producing the same, and a resin film containing the same.

[0002] The resin may be mixed with a colorant for the purpose of coloring, etc. In relation to such colorants, Patent Document 1 describes, for example, a method for producing a colored pigment in which an anionic or cationic clay substantially free of clay sheet aggregates is subjected to ion exchange with an organic dye.

[0003] Patent Document 2 describes a leaching-resistant colored spherical cellulose pigment, the surface of which is coated with a hydrotalcite-type layered double hydroxide containing dye anions between the crystal structure layers.

[0004] Patent Document 3 describes a polyester composition with good dyeability, which contains 0.1 to 10% by mass of hydrotalcites or oxide solid solutions based on the polyester.

[0005] JP 2003-504481 A JP 2008-266479 A JP 2004-263123 A

[0006] However, Patent Documents 1 and 2 do not consider at all colorants used to color resin films, and Patent Document 3 does not consider at all dyeability when an anion with an absorption wavelength of 450 nm or more is used as a colorant.

[0007] Therefore, an object of the present disclosure is to provide a hydrotalcite compound that can realize a resin film with good appearance, a method for producing the same, and such a resin film.

[0008] A first embodiment of the present disclosure provides a resin film comprising a hydrotalcite-type compound and a resin, wherein the hydrotalcite-type compound comprises one or more types of anions, and the anions comprise at least an anion having absorption at a wavelength of 450 nm or more.

[0009] In a second embodiment of the present disclosure, the resin in the first embodiment may include a polyolefin resin.

[0010] In a third embodiment of the present disclosure, in any one of the first and second embodiments, the hydrotalcite compound may include a compound represented by the following formula (I): [M1 ２＋ １－ｘ M2 ３＋ ｘ (OH) ２ ][(A1 ｎ－ ) ｘ／ｎ ・mH ２ O] ... (I) In a third embodiment of the present disclosure, in any one of the first and second embodiments, M1 in the above formula (I) ２＋ In the third embodiment of the present disclosure, in any one of the first and second embodiments, M2 in the above formula (I) may represent one or more divalent metal ions. ３＋ In the third embodiment of the present disclosure, in any one of the first and second embodiments, A1 in the above formula (I) may represent one or more trivalent metal ions. ｎ－ represents one or more n-valent anions, and the one or more n-valent anions may include at least an anion having absorption at a wavelength of 450 nm or more. In a third embodiment of the present disclosure, in any one of the first and second embodiments, m in the above formula (I) may be 0 or more and less than 1. In a third embodiment of the present disclosure, in any one of the first and second embodiments, n in the above formula (I) may be 1 or more and 5 or less. In a third embodiment of the present disclosure, in any one of the first and second embodiments, x in the above formula (I) may be more than 0 and less than 0.5.

[0011] In a fourth embodiment of the present disclosure, in any one of the first to third embodiments, M1 ２＋ However, Mg ２＋ and Zn ２＋In a fourth embodiment of the present disclosure, in any one of the first to third embodiments, M2 ３＋ But, Al ３＋ and Fe ３＋ It may contain one or more selected from:

[0012] In a fifth embodiment of the present disclosure, in any one of the first to fourth embodiments, the anion having absorption at a wavelength of 450 nm or more may include one or more anions selected from a triarylmethane-based anion, a naphthoquinoneimine-based anion, an anthraquinone-based anion, a xanthene-based anion, an azo-based anion, a quinoline-based anion, an indigo-based anion, and a perylene-based anion.

[0013] In a sixth embodiment of the present disclosure, in any one of the first to fifth embodiments, the anions may further include carbonate ions and nitrate ions.

[0014] In a seventh embodiment of the present disclosure, in any one of the first to sixth embodiments, the polyolefin resin may contain one or more selected from the group consisting of polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, a copolymer of ethylene and an α-olefin other than polyethylene, a copolymer of ethylene and ethyl acrylate or methyl acrylate, a copolymer of propylene and an α-olefin other than polypropylene, and a copolymer of ethylene, propylene, 1-butene or 4-methyl-1-pentene, and vinyl acetate.

[0015] In an eighth embodiment of the present disclosure, in any one of the first to seventh embodiments, the hydrotalcite-based compound may include a hydrotalcite-based compound that has been surface-treated with a higher fatty acid.

[0016] In a ninth embodiment of the present disclosure, in any one of the first to eighth embodiments, the resin film may have a thickness of 1 μm or more and 1,000 μm or less.

[0017] In a tenth embodiment of the present disclosure, in any one of the first to ninth embodiments, the ratio of the total charge derived from the anions having absorption at wavelengths of 450 nm or more to the total charge of the anions can be 0.1% or more and 20% or less.

[0018] In an eleventh embodiment of the present disclosure, in any one of the first to tenth embodiments, the content of the hydrotalcite-type compound contained in the resin film may be 0.001 mass% or more and 0.1 mass% or less, based on a total of 100 mass% of the resin film.

[0019] In a twelfth embodiment of the present disclosure, in any one of the first to eleventh embodiments, the hydrotalcite compound may further contain a compound represented by the following formula (II): [M3 ２＋ １－ｙ M4 ３＋ ｙ (OH) ２ ][(A2 ｑ－ ) ｙ／ｑ pH ２ O] ... (II) In a twelfth embodiment of the present disclosure, in any one of the first to eleventh embodiments, M3 in the above formula (II) ２＋ is Mg ２＋ , Zn ２＋ , Ca ２＋ , Sr ２＋ , Cu ２＋ , Fe ２＋ , Mn ２＋ , Co ２＋ , Ni ２＋ , Sn ２＋ , Pb ２＋ , Cd ２＋ and Ba ２＋ In a twelfth embodiment of the present disclosure, in any one of the first to eleventh embodiments, M4 in the above formula (II) may represent one or more metal ions selected from the group consisting of ３＋ is Al ３＋ and Fe ３＋In a twelfth embodiment of the present disclosure, in any one of the first to eleventh embodiments, A2 in the above formula (II) may represent one or more metal ions selected from ｑ－ may represent one or more q-valent anions. In a twelfth embodiment of the present disclosure, in any one of the first to eleventh embodiments, p in the above formula (II) may be 0 or more and less than 1. In a twelfth embodiment of the present disclosure, in any one of the first to eleventh embodiments, q in the above formula (II) may be 1 or more and 5 or less. In a twelfth embodiment of the present disclosure, in any one of the first to eleventh embodiments, y in the above formula (II) may be more than 0 and less than 0.5.

[0020] A thirteenth embodiment of the present disclosure provides a hydrotalcite compound represented by the following formula (I): [M1 ２＋ １－ｘ M2 ３＋ ｘ (OH) ２ ][(A1 ｎ－ ) ｘ／ｎ ・mH ２ O] ... (I) In a thirteenth embodiment of the present disclosure, in formula (I), M1 ２＋ represents one or more divalent metal ions. In a thirteenth embodiment of the present disclosure, in formula (I), M2 ３＋ represents one or more trivalent metal ions. In a thirteenth embodiment of the present disclosure, in formula (I), A1 ｎ－ represents one or more n-valent anions. In a thirteenth embodiment of the present disclosure, in formula (I), the one or more n-valent anions include at least an organic dye having an anion with absorption at a wavelength of 450 nm or more. In a thirteenth embodiment of the present disclosure, in formula (I), m is 0 or more and less than 1. In a thirteenth embodiment of the present disclosure, in formula (I), n is 1 or more and 5 or less. In a thirteenth embodiment of the present disclosure, in formula (I), x is more than 0 and less than 0.5. In a thirteenth embodiment of the present disclosure, the anions further include carbonate ions and nitrate ions. In a thirteenth embodiment of the present disclosure, the hydrotalcite compound is surface-treated with a higher fatty acid.

[0021] In the fourteenth embodiment of the present disclosure, in the first embodiment, the M1 ２＋ is Mg ２＋ and Zn ２＋ In the fourteenth embodiment of the present disclosure, in the first embodiment, M2 ３＋ is Al ３＋ and Fe ３＋ The compound may contain one or more selected from the group consisting of:

[0022] In a fifteenth embodiment of the present disclosure, in any one of the first and second embodiments, the organic dye of anion having absorption at a wavelength of 450 nm or more may contain one or more anions selected from triarylmethane-based anions, naphthoquinoneimine-based anions, anthraquinone-based anions, xanthene-based anions, azo-based anions, quinoline-based anions, indigo-based anions, and perylene-based anions.

[0023] In a sixteenth embodiment of the present disclosure, in any one of the thirteenth to fifteenth embodiments, the ratio of the total charge derived from the anionic organic dye having absorption at wavelengths of 450 nm or more to the total charge of the anions can be 0.1% or more and 20% or less.

[0024] A seventeenth embodiment of the present disclosure provides a resin film including any one of the hydrotalcite-based compounds according to the thirteenth to sixteenth embodiments and a resin. In the seventeenth embodiment of the present disclosure, the resin may include a polyolefin-based resin.

[0025] In an eighteenth embodiment of the present disclosure, in the seventeenth embodiment, the polyolefin resin may contain one or more selected from the group consisting of: polyethylene; polypropylene; polybutene-1; poly-4-methylpentene-1; a copolymer of ethylene and an α-olefin other than polyethylene; a copolymer of ethylene and ethyl acrylate or methyl acrylate; a copolymer of propylene and an α-olefin other than polypropylene; and a copolymer of ethylene, propylene, 1-butene, or 4-methyl-1-pentene, with vinyl acetate.

[0026] In a 19th embodiment of the present disclosure, in any one of the 17th and 18th embodiments, the content of the hydrotalcite-type compound contained in the resin film can be 0.001 mass% or more and 0.1 mass% or less, based on a total of 100 mass% of the resin film.

[0027] In a twentieth embodiment of the present disclosure, in any one of the seventeenth to nineteenth embodiments, a hydrotalcite compound represented by the following formula (II) may be further contained. [M3 ２＋ １－ｙ M4 ３＋ ｙ (OH) ２ ][(A2 ｑ－ ) ｙ／ｑ pH ２ O] (II) In a twentieth embodiment of the present disclosure, in any one of the seventeenth to nineteenth embodiments, M3 in the above formula (II) ２＋ is Mg ２＋ , Zn ２＋ , Ca ２＋ , Sr ２＋ , Cu ２＋ , Fe ２＋ , Mn ２＋ , Co ２＋ , Ni ２＋ , Sn ２＋ , Pb ２＋ , Cd ２＋ and Ba ２＋ In the 20th embodiment of the present disclosure, in any one of the 17th to 19th embodiments, M4 in the above formula (II) may represent one or more metal ions selected from the group consisting of ３＋ is Al ３＋ and Fe ３＋ In the twentieth embodiment of the present disclosure, in any one of the seventeenth to nineteenth embodiments, A2 in the above formula (II) may represent one or more metal ions selected from ｑ－may represent one or more q-valent anions. In the twentieth embodiment of the present disclosure, in any one of the seventeenth to nineteenth embodiments, p in the above formula (II) may be 0 or more and less than 1. In the twentieth embodiment of the present disclosure, in any one of the seventeenth to nineteenth embodiments, q in the above formula (II) may be 1 or more and 5 or less. In the twentieth embodiment of the present disclosure, in any one of the seventeenth to nineteenth embodiments, y in the above formula (II) may be more than 0 and less than 0.5.

[0028] A twenty-first embodiment of the present disclosure provides a method for producing a hydrotalcite-type compound, the method comprising: a surface treatment step of mixing a hydrotalcite-type compound containing a first anion with a higher fatty acid, and heating and holding the mixture to treat a surface of the hydrotalcite-type compound with the higher fatty acid; a substitution step of, after the surface treatment step, adding an acid having a second anion, the second anion having a smaller valence than the first anion, as a conjugate base, and further heating and holding the mixture to substitute at least a portion of the first anion with the second anion; and a retention step of, after the substitution step, adding an organic dye having absorption at a wavelength of 450 nm or more, and further heating and holding the mixture to allow the organic dye to be retained in the hydrotalcite-type compound.

[0029] In the twenty-second embodiment of the present disclosure, in the twenty-first embodiment, the substitution step can be carried out at a pH range of 2 to 5.

[0030] In a 23rd embodiment of the present disclosure, in any one of the 20th and 21st embodiments, the first anion may include a carbonate ion and / or a sulfate ion, and the second anion may include a nitrate ion.

[0031] According to the present disclosure, it is possible to provide a hydrotalcite-based compound capable of realizing a resin film with good appearance, a method for producing the same, and such a resin film.

[0032] The hydrotalcite-based compound of the present disclosure is a hydrotalcite-based compound represented by the following formula (I): [M1 ２＋ １－ｘ M2３＋ ｘ (OH) ２ ][(A1 ｎ－ ) ｘ／ｎ ・mH ２ O] ... (I) [In formula (I), M1 ２＋ represents one or more divalent metal ions, M2 ３＋ represents one or more trivalent metal ions, and A1 ｎ－ represents one or more n-valent anions, the one or more n-valent anions including at least an anionic organic dye having absorption at wavelengths of 450 nm or more, m is 0 or more and less than 1, n is 1 or more and 5 or less, and x is more than 0 and less than 0.5.] The anions further include carbonate ions and nitrate ions, and the surface of the hydrotalcite-based compound is surface-treated with a higher fatty acid.

[0033] The hydrotalcite-based compound of the present disclosure can realize a resin film with good appearance. Although the present disclosure should not be interpreted as being limited to a particular theory, the reason why the hydrotalcite-based compound of the present disclosure can exhibit such an effect is thought to be as follows.

[0034] That is, the hydrotalcite-based compound includes two or more base layers and one or more types of anions present between two adjacent base layers. The two or more base layers are composed of a double hydroxide containing a divalent metal and a trivalent metal. Because the base layers are positively charged, the anions can be stabilized between the two adjacent base layers. In addition, in the hydrotalcite-based compound of the present disclosure, the surface is treated with a higher fatty acid, which is thought to stabilize nitrate ions. As a result, it is thought that the interlayer distance of the hydrotalcite-based compound is likely to increase. Therefore, it is thought that the anionic organic dye is more likely to exist stably, making it possible to realize a resin film with a good appearance.

[0035] In the present disclosure, "hydrotalcite" means hydrotalcite in a broad sense, and ６ Al ２ (OH) １６ ][(CO ３－ ) 4H ２ The term "hydrotalcite" in the present disclosure is not limited to hydrotalcite in the narrow sense represented by the formula [0]. The term "hydrotalcite" in the present disclosure also includes compounds that differ in the type and amount of metals and the type and amount of anions compared to the hydrotalcite in the narrow sense described above.

[0036] In addition, in the present disclosure, "hydrotalcite-type compound" means a compound classified as hydrotalcite, which contains an anion that has absorption at wavelengths of 450 nm or more.

[0037] M1 ２＋ represents one or more divalent metal ions. ２＋ is Mg ２＋ , Zn ２＋ , Ca ２＋ , Sr ２＋ , Cu ２＋ , Fe ２＋ , Mn ２＋ , Co ２＋ , Ni ２＋ , Sn ２＋ , Pb ２＋ , Cd ２＋ and Ba ２＋ Preferably, the composition contains one or more selected from the group consisting of Mg ２＋ and Zn ２＋ It is more preferable that the compound contains one or more selected from the following: ２＋ However, Mg ２＋ and Zn ２＋ By including one or more selected from the above, the stability of the compound represented by formula (I) can be improved.

[0038] M2 ３＋ represents one or more trivalent metal ions. ３＋ is Al ３＋ , Fe ３＋ , Sc ３＋ , Y ３＋ , Ti ３＋ , Cr ３＋ , Fe ３＋ , Al ３＋ , Ga ３＋ , In ３＋ and La ３＋It is preferable that the composition contains one or more selected from the group consisting of Al ３＋ and Fe ３＋ It is more preferable that the compound contains one or more selected from the following: ３＋ But, Al ３＋ and Fe ３＋ By including one or more selected from the above, the stability of the compound represented by formula (I) can be improved.

[0039] A1 ｎ－ represents one or more n-valent anions, and the one or more n-valent anions include at least an anion having absorption at wavelengths of 450 nm or longer. Hereinafter, the anion having absorption at wavelengths of 450 nm or longer is also referred to as a dye anion.

[0040] The absorption wavelength of the dye anion may be, for example, 450 nm or more and 830 nm or less, preferably 500 nm or more and 605 nm or less, more preferably 500 nm or more and 595 nm or less, and even more preferably 560 nm or more and 595 nm or less. The absorption wavelength of the dye anion may be, for example, 450 nm or more, preferably 500 nm or more and more preferably 560 nm or more. The absorption wavelength of the dye anion may be, for example, 830 nm or less, preferably 605 nm or less and more preferably 595 nm or less. When the absorption wavelength of the dye anion is within this range, even if the resin discolors due to the influence of heat, light, oxygen, chemicals, or the like, the dye anion can exhibit a complementary color, thereby making it possible to counteract the discoloration of the resin.

[0041] The valence of the dye anion is not limited. The valence of the dye anion may be preferably 1 or more, more preferably 2 or more and 5 or less, and even more preferably 3 or more and 4 or less. The valence of the dye anion may be preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. The valence of the dye anion may be preferably 5 or less, and more preferably 4 or less.

[0042] The dye anion may be one or more selected from the group consisting of triarylmethane anions, naphthoquinoneimine anions, anthraquinone anions, xanthene anions, azo anions, quinoline anions, indigo anions, and perylene anions. By including these anions, the dye anion can be stably present in the hydrotalcite compound. Preferably, the dye anion is a triarylmethane anion.

[0043] In one aspect, the dye anion preferably contains a low-toxicity anion. This allows for a resin film that is highly safe for the human body to be provided, for example, a resin film that complies with the Japanese Food Sanitation Act or the Japanese Pharmaceutical Affairs Act. In the present disclosure, low toxicity means, for example, that the acceptable daily intake (ADI) is 0.1 mg / kg body weight / day in a one-year repeated-dose toxicity test.

[0044] The dye anions with low toxicity may be green, blue, brown, purple, etc. In the present disclosure, the term "dye" refers to not only the dye compound itself but also the anion that is extracted from the dye compound with Na. ＋ Also included are anions resulting from the elimination of metal ions such as:

[0045] Examples of the green dyes include Fast Green FCF, Alizarin Cyanine Green F, Quinizarin Green SS, Pyranine Conch, and Light Green SF Yellow. Examples of the blue dyes include Brilliant Blue FCF, Indigo Carmine, Indigo, Patent Blue NA, Patent Blue CA, Carbanthrene Blue, and Alphazurine FG. Examples of the brown dyes include Resorcinol Brown. Examples of the purple dyes include Alizurine Purple SS.

[0046] Examples of the anionic group include a sulfonic acid group, a carboxy group, and alkali metal salts of a sulfonic acid group or a carboxy group.

[0047] The dye anion having low toxicity is preferably the blue or purple dye, more preferably the blue dye, and even more preferably Brilliant Blue FCF.

[0048] The dye anion may have a major axis of, for example, 1 nm or more and 3 nm or less. The dye anion may have a minor axis of, for example, 0.5 nm or more and 1 nm or less. The dye anion may have a thickness of, for example, 0.1 nm or more and 0.5 nm or less. When the major axis, minor axis, and thickness of the dye anion are within these ranges, the dye anion can be stably present in the hydrotalcite compound.

[0049] In the present disclosure, the major axis of an anion refers to the length of the longest diameter of the anion. The minor axis of an anion refers to the length of the longest diameter among the diameters perpendicular to the major axis of the anion. The thickness of an anion refers to the maximum length in a direction perpendicular to a plane containing the major axis and minor axis of the anion. The major axis, minor axis, and thickness of an anion may be estimated values ​​calculated based on the structure of the anion.

[0050] The content of the low-toxicity dye anions is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less, based on 100% by mass of the total dye anions. The content of the low-toxicity dye anions is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and preferably 100% by mass or less, based on 100% by mass of the total dye anions. When the content of the low-toxicity dye anions is within this range, a resin film that is highly safe for the human body can be provided, and in particular, a resin film that complies with the Food Sanitation Act or the Pharmaceutical Affairs Act can be provided.

[0051] In the hydrotalcite-based compound, the ratio of the total charges derived from the dye anions to the total charges of the anions is preferably 0.1% or more and 20% or less, more preferably 2% or more and 18% or less, and even more preferably 5% or more and 18% or less. In the hydrotalcite-based compound, the ratio of the total charges derived from the dye anions to the total charges of the anions is preferably 0.1% or more, more preferably 2% or more, and even more preferably 5% or more. In the hydrotalcite-based compound, the ratio of the total charges derived from the dye anions to the total charges of the anions is preferably 20% or less, more preferably 18% or less. When the ratio of the total charges derived from the dye anions is within this range, the dye anions can be stably present in the hydrotalcite-based compound, and the hue and saturation of the resin film can be easily controlled. Note that, in the present disclosure, the total charges of the anions do not include charges derived from hydroxide ions.

[0052] When the amount of dye anions contained per mole of compound (I) is Y moles and the valence of the dye anions is n1, the total charge derived from the dye anions is expressed as Y×n1. Furthermore, the total valence of the anions contained per mole of compound (I) is x. In this case, the ratio of the total charge of the anions derived from the dye anions to the total charge of the anions contained in formula (I) is expressed as (Y×n1) / x. (Y×n1) / x is preferably 0.1% or more and 20% or less, more preferably 2% or more and 18% or less, and even more preferably 5% or more and 18% or less. (Y×n1) / x is preferably 0.1% or more, more preferably 2% or more, and even more preferably 5% or more. Furthermore, (Y×n1) / x is preferably 20% or less, more preferably 18% or less, and even more preferably 18% or less. When (Y×n1) / x is within this range, the dye anion can be stably present in the hydrotalcite compound, and the hue and saturation of the resin film can be easily controlled.

[0053] m is 0 or more and less than 1, and preferably 0 or more and 0.5 or less. n is 1 or more and 5 or less, and preferably 1 or more and 3 or less. When two or more types of anions are contained, n may be calculated as a weighted average based on the charge and molar content of each anion. x is more than 0 and less than 0.5, and preferably 0.1 or more and 0.4 or less. x is more than 0, preferably 0.1 or more and less than 0.5, and preferably 0.4 or less.

[0054] The one or more n-valent anions further include carbonate ions and nitrate ions. The coexistence of carbonate ions and nitrate ions with the dye anions is thought to stabilize the physical properties of the hydrotalcite-based compound due to physical and electrochemical factors.

[0055] The ratio of the charge derived from carbonate ions to the total charge of the anions may be 20% or more and 99.9% or less, 50% or more and 99% or less, or 60% or more and 98% or less. The ratio of the charge derived from carbonate ions to the total charge of the anions may be 20% or more, 50% or more, or 60% or more. Furthermore, the ratio of the charge derived from carbonate ions to the total charge of the anions may be 99.9% or less, 99% or less, or 98% or less. When the ratio of the charge derived from carbonate ions is within this range, the dye anions can be stably present in the hydrotalcite compound.

[0056] The ratio of the charge derived from nitrate ions to the total charge of the anions may be 0% or more and 30% or less, or 0% or more and 20% or less. When the ratio of the charge derived from carbonate ions is within this range, the dye anions can be present stably in the hydrotalcite-based compound. When the ratio of the charge derived from nitrate ions is within this range, the dye anions can be present stably in the hydrotalcite-based compound.

[0057] The one or more n-valent anions may include other anions in addition to the dye anion, carbonate ion, and nitrate ion. The valence of the other anions is not limited. The valence of the other anions may be preferably 1 or more, more preferably 1 to 5, and even more preferably 1 to 3.

[0058] Specific examples of the other anions include phosphate ions and bicarbonate ions. The other anions preferably include carbonate ions, and more preferably include carbonate ions and nitrate ions.

[0059] The major axis of the other anions may be, for example, 0.3 nm or more and 0.5 nm or less. When the major axis of the other anions is in this range, the dye anions can be stably present in the hydrotalcite compound.

[0060] The hydrotalcite compound is surface-treated with a higher fatty acid. By being surface-treated with a higher fatty acid, dye anions can be stably present in the hydrotalcite compound. In the present disclosure, "surface-treated with a higher fatty acid" means that the surface of the hydrotalcite is entirely or partially coated with the higher fatty acid by the surface treatment with the higher fatty acid.

[0061] The higher fatty acid may be a saturated higher fatty acid or an unsaturated higher fatty acid. Examples of the higher fatty acid include saturated higher fatty acids such as lauric acid, myristic acid, palmitic acid, erucic acid, stearic acid, arachic acid, and behenic acid, and unsaturated higher fatty acids such as palmitoleic acid, oleic acid, elaidic acid, linoleic acid, linolenic acid, erucic acid, and ricinoleic acid. In one aspect, the higher fatty acid is preferably a saturated higher fatty acid, and more preferably stearic acid, erucic acid, palmitic acid, lauric acid, and behenic acid. The higher fatty acid preferably includes a plant-derived higher fatty acid.

[0062] The proportion of the higher fatty acid is preferably 0.1% by mass or more and 10.0% by mass or less, more preferably 0.5% by mass or more and 8.0% by mass or less, and even more preferably 1.0% by mass or more and 5.0% by mass or less, based on a total of 100% by mass of the hydrotalcite-based compounds surface-treated with the higher fatty acid. The proportion of the higher fatty acid is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, based on a total of 100% by mass of the hydrotalcite-based compounds surface-treated with the higher fatty acid. The proportion of the higher fatty acid is preferably 10.0% by mass or less, more preferably 8.0% by mass or less, and even more preferably 5.0% by mass or less, based on a total of 100% by mass of the hydrotalcite-based compounds surface-treated with the higher fatty acid. Having the proportion of the higher fatty acid within this range can improve the dispersibility of the resulting hydrotalcite-based compound in the resin and facilitate increasing the content of dye anions.

[0063] The hydrotalcite-based compound is preferably in particulate form. The average secondary particle diameter of the hydrotalcite-based compound is preferably 0.1 μm or more and 5 μm or less, more preferably 0.15 μm or more and 2 μm or less, and even more preferably 0.2 μm or more and 1.5 μm or less. The average secondary particle diameter of the hydrotalcite-based compound is preferably 0.1 μm or more, more preferably 0.15 μm or more, and even more preferably 0.2 μm or more. The average secondary particle diameter of the hydrotalcite-based compound is preferably 5 μm or less, more preferably 2 μm or less, and even more preferably 1.5 μm or less. When the average secondary particle diameter of the hydrotalcite-based compound is within this range, the haze of the resulting resin film can be suppressed to a low level.

[0064] The average secondary particle diameter of the hydrotalcite compound means the cumulative 50% volume diameter, i.e., D50, and can be measured by dynamic light scattering.

[0065] The BET specific surface area of ​​the hydrotalcite compound is preferably 12 m ２ / g or more 20m ２ / g or less, more preferably 14m ２ / g or more 18m ２The BET specific surface area of ​​the hydrotalcite compound is preferably 12 m ２ / g or more, more preferably 14m ２ / g or more, preferably 120m ２ / g or less, more preferably 18m ２ The BET specific surface area of ​​the hydrotalcite-based compound can be measured by the BET method using nitrogen gas as the adsorbate.

[0066] The hydrotalcite-type compound can be produced by a production method including: a surface treatment step of coating the surface of hydrotalcite containing a first anion with a higher fatty acid or a salt thereof; a substitution step of substituting, after the surface treatment step, at least a portion of the first anion with a second anion having a smaller valence than the first anion; and a retention step of retaining, after the substitution step, an organic dye having absorption at wavelengths of 450 nm or more on the hydrotalcite.

[0067] In the surface treatment step, the surface of the hydrotalcite containing the first anion is coated with a higher fatty acid or a salt thereof, thereby obtaining hydrotalcite surface-treated with the higher fatty acid. Such coating treatment can be carried out, for example, by mixing the hydrotalcite containing the first anion with the higher fatty acid and heating and maintaining the mixture.

[0068] The hydrotalcite is not limited as long as it contains a first anion. In one embodiment, the hydrotalcite-type compound may contain two or more basic layers made of a double hydroxide containing a divalent metal and a trivalent metal, and one or more types of anions present between two adjacent basic layers. Since the basic layers are positively charged, the anions can be stabilized between the two adjacent basic layers.

[0069] The divalent metal may be one or more types. The divalent metal preferably includes one or more types selected from the group consisting of Mg, Zn, Ca, Sr, Cu, Fe, Mn, Co, Ni, Sn, Pb, Cd, and Ba, and more preferably includes one or more types selected from Mg and Zn. When the divalent metal includes one or more types selected from Mg and Zn, the stability of the resulting hydrotalcite-type compound is good.

[0070] The trivalent metal may be one or more types. The trivalent metal preferably contains one or more types selected from the group consisting of Al, Fe, Sc, Y, Ti, Cr, Fe, Al, Ga, In, and La, and more preferably contains one or more types selected from Al and Fe. When the trivalent metal contains one or more types selected from Al and Fe, the stability of the obtained hydrotalcite-based compound is good.

[0071] The first anion is preferably a monovalent or divalent anion. The first anion is preferably one or more selected from carbonate ion, bicarbonate ion, and sulfate ion, more preferably carbonate ion and / or sulfate ion. The hydrotalcite containing the first anion may also contain anions other than the first anion.

[0072] The content of the carbonate ions and / or sulfate ions may be preferably 80 mol% or more and 100 mol% or less, more preferably 90 mol% or more and 100 mol% or less, and even more preferably 95 mol% or more and 100 mol% or less, based on 100 mol% of the first anions.

[0073] The hydrotalcite containing the first anion can be produced by a production method including the steps of: mixing, in an aqueous medium, an aqueous solution of a water-soluble metal salt of a divalent metal, an aqueous solution of a water-soluble metal salt of a trivalent metal, an alkali metal hydroxide, and an aqueous solution of a salt of an alkali metal cation and a first anion to obtain a mixed solution; maintaining the pH of the mixed solution at 8 or higher to coprecipitate a hydrotalcite precursor; and washing the hydrotalcite precursor with an aqueous solution of a salt of an alkali metal cation and a first anion to obtain a hydrotalcite compound containing the first anion.

[0074] The hydrotalcite containing the first anion may further be subjected to hydrothermal treatment. The hydrothermal treatment can suppress crystal growth and aggregation of the hydrotalcite. The hydrothermal treatment can be carried out using an autoclave. The temperature of the hydrothermal treatment is preferably 100°C or higher, more preferably 120 to 200°C, and the time of the hydrothermal treatment is preferably 10 hours or longer. The carbonate ion-containing hydrotalcite may be dehydrated, dried, pulverized, and classified as necessary.

[0075] As the water-soluble metal salt of the divalent metal, for example, magnesium chloride can be used. As the water-soluble metal salt of the trivalent metal, for example, aluminum sulfate can be used. As the alkali metal hydroxide, for example, sodium hydroxide can be used. As the salt of the alkali metal cation and the first cation, for example, sodium carbonate and sodium nitrate can be used. The pH range of the mixed solution is preferably 9 to 11.

[0076] The hydrotalcite containing the first anion may be further calcined before being subjected to the surface treatment step. By calcining the hydrotalcite, hydration water and hydroxyl groups can be eliminated, and an oxide having a positively charged surface is obtained. It is believed that the positively charged surface of the obtained oxide makes it easier for the organic dye described below to be adsorbed onto the surface of the hydrotalcite.

[0077] The temperature during the firing may be preferably 300° C. or higher and 900° C. or lower, more preferably 350° C. or higher and 800° C. or lower, and even more preferably 400° C. or higher and 700° C. or lower. The temperature during the firing may be preferably 300° C. or higher, more preferably 350° C. or higher, and even more preferably 400° C. or higher, and preferably 900° C. or lower, more preferably 800° C. or lower, and even more preferably 700° C. or lower.

[0078] The hydrotalcite containing the first anion is not limited to that produced by the above production method.

[0079] The higher fatty acid used in the surface treatment step has the same meaning as the higher fatty acid described above. The salt of the higher fatty acid is preferably an alkali metal salt of the higher fatty acid, more preferably a sodium salt of the higher fatty acid.

[0080] In the surface treatment step, the amount of the higher fatty acid or its salt may be preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 10 parts by mass or less, and even more preferably 1 part by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the hydrotalcite containing the first anion.

[0081] In the surface treatment step, the heating temperature during heating and holding may be preferably 70° C. or higher and 95° C. or lower, more preferably 75° C. or higher and 90° C. or lower, and even more preferably 80° C. or higher and 85° C. or lower. By heating and holding at such a temperature, the surface treatment with the higher fatty acid can be promoted.

[0082] In the surface treatment step, the heating time is preferably 10 to 60 minutes, more preferably 20 to 50 minutes, and even more preferably 30 to 40 minutes. By heating and maintaining the mixture under such conditions, the surface treatment with the higher fatty acid can be promoted.

[0083] In the substitution step, after the surface treatment step, at least a portion of the first anion is substituted with a second anion having a lower valence than the first anion. This results in a hydrotalcite surface-treated with a higher fatty acid, containing the second anion and, optionally, the first anion as an anion. While not intended to be limited to a particular theory, it is believed that the second anion, which has a lower valence than the first anion, tends to increase the distance between the base layers of the hydrotalcite. Therefore, it is believed that substituting the first anion with the second anion facilitates substitution with an organic dye. Such surface treatment can be carried out, for example, by adding an acid having a conjugate base of a second anion having a lower valence than the first anion to the surface-treated hydrotalcite, and then heating and holding the mixture.

[0084] The second anion is preferably a divalent or higher anion, more preferably a divalent to pentavalent anion, and even more preferably a divalent to trivalent anion. The second anion is preferably one or more anions selected from the group consisting of nitrate anion and phosphate anion, and more preferably nitrate anion.

[0085] The acid having the second anion as a conjugate base is preferably nitric acid or phosphoric acid, more preferably nitric acid.

[0086] The content of the nitric acid may be preferably 80 mol % or more and 100 mol % or less, more preferably 90 mol % or more and 100 mol % or less, and even more preferably 95 mol % or more and 100 mol % or less, based on 100 mol % of the second anion.

[0087] In the substitution step, the amount of the acid having a second anion having a smaller valence than the first anion as a conjugate base may be preferably 10 mol % or more and 250 mol % or less, more preferably 20 mol % or more and 240 mol % or less, and even more preferably 40 mol % or more and 220 mol % or less, relative to 100 mol % of the hydrotalcite containing the first anion.

[0088] In the substitution step, the heating temperature during heating and holding may be preferably 70° C. or higher and 95° C. or lower, more preferably 75° C. or higher and 90° C. or lower, and even more preferably 80° C. or higher and 85° C. or lower. By heating and holding at such a temperature, substitution of anions can be promoted.

[0089] In the substitution step, the heating time is preferably 10 minutes or more and 60 minutes or less, more preferably 20 minutes or more and 50 minutes or less, and even more preferably 30 minutes or more and 40 minutes or less. By heating and maintaining the mixture under such conditions, substitution of anions can be promoted.

[0090] In a preferred embodiment, the substitution step can be carried out in water. The substitution step can be preferably carried out at a pH range of 2 or more and 5 or less. The pH range in the substitution step can be preferably 2.5 or more and 4.5 or less, more preferably 3 or more and 4 or less. When the pH range in the substitution step is within this range, substitution with the second anion can be further promoted.

[0091] In the holding step, an organic dye having absorption at wavelengths of 450 nm or longer is added to the surface-treated hydrotalcite in which at least a portion of the first anions have been substituted with second anions, and the mixture is further heated and held, whereby the organic dye is held in the hydrotalcite, and a hydrotalcite-type compound is obtained.

[0092] The organic dye may be one or more selected from the group consisting of triarylmethane dyes, naphthoquinoneimine dyes, anthraquinone dyes, xanthene dyes, azo dyes, quinoline dyes, indigo dyes, and perylene dyes. By using these organic dyes, dye anions derived from the organic dyes can be stably present in the obtained hydrotalcite compound. Preferably, the organic dye is a triarylmethane dye.

[0093] In the present disclosure, the organic dye includes not only the organic dye itself but also a dye obtained by condensing the organic dye with Na. ＋Therefore, in the hydrotalcite-based compound, the dye may be present in the form of an anion.

[0094] In the retention step, the amount of the organic dye may be preferably 1 mol % or more and 50 mol % or less, more preferably 5 mol % or more and 40 mol % or less, and even more preferably 7 mol % or more and 35 mol % or less, relative to 100 mol % of the hydrotalcite containing the first anion.

[0095] In the holding step, the heating temperature during heating and holding may be preferably 70° C. or higher and 95° C. or lower, more preferably 75° C. or higher and 90° C. or lower, and even more preferably 80° C. or higher and 85° C. or lower. By heating and holding at such a temperature, it is possible to promote the retention of the organic dye while suppressing the decomposition of the hydrotalcite.

[0096] In the above-mentioned holding step, the heating time during heating and holding is preferably 10 minutes to 60 minutes, more preferably 20 minutes to 50 minutes, and even more preferably 30 minutes to 40 minutes. By holding the mixture under such conditions, it is possible to suppress decomposition of the hydrotalcite and promote the retention of the organic dye.

[0097] The resin film of the present disclosure contains a hydrotalcite-based compound and a resin, and the hydrotalcite-based compound contains one or more types of anions, and the anions contain at least an anion that has absorption at wavelengths of 450 nm or greater.

[0098] The resin film of the present disclosure has a good appearance, and preferably has good appearance and mechanical properties. In a preferred embodiment, the resin film of the present disclosure is inhibited from yellowing and has good mechanical properties. In a more preferred embodiment, the resin film of the present disclosure is inhibited from yellowing, has low haze, and has good mechanical properties. In the present disclosure, good appearance can mean that the resin film is free of mottling and looks clean, due in part to the good dispersibility of the hydrotalcite-based compound itself, which has a blue tint that counteracts the yellowing of the resin. Although the present disclosure should not be interpreted as being limited to a particular theory, the reasons why the resin film of the present disclosure has a good appearance, and preferably has good appearance and mechanical properties, are thought to be as follows.

[0099] That is, in the resin film of the present disclosure, anions having absorption at wavelengths of 450 nm or more are present in an intercalated state in the hydrotalcite-type compound, and are believed to be stabilized and less susceptible to the effects of ultraviolet light, heat, water, and other chemicals. Furthermore, hydrotalcite-type compounds have excellent dispersibility in resins, resulting in uniform color development in the resin film and suppressing deterioration in mechanical properties such as tensile strength. Furthermore, because of their excellent dispersibility in resins, their size in the resin is small, which can suppress filter clogging during film production. Additionally, because the hydrotalcite-type compound contains anions having absorption at wavelengths of 450 nm or more, and the hydrotalcite-type compound has good dispersibility in the resin, migration of pigment components to the outside of the resin can be suppressed. Anions having absorption at a wavelength of 450 nm exhibit a hue corresponding to the absorption wavelength and can therefore act as dyes.

[0100] The hydrotalcite-based compound contains one or more anions, and the anions contain at least an organic dye having an anion that absorbs light at wavelengths of 450 nm or longer. This allows the hydrotalcite-based compound to function as a colorant and impart a color to the resin film that corresponds to the absorption wavelength.

[0101] The dye anion has the same meaning as the dye anion explained in the first production method.

[0102] In the hydrotalcite-based compound, the ratio of the total charges derived from the dye anions to the total charges of the anions is preferably 0.1% or more and 20% or less, more preferably 2% or more and 18% or less, and even more preferably 5% or more and 18% or less. In the hydrotalcite-based compound, the ratio of the total charges derived from the dye anions to the total charges of the anions is preferably 0.1% or more, more preferably 2% or more, and even more preferably 5% or more. In the hydrotalcite-based compound, the ratio of the total charges derived from the dye anions to the total charges of the anions is preferably 20% or less, more preferably 18% or less. When the ratio of the total charges derived from the dye anions is within this range, the dye anions can be stably present in the hydrotalcite-based compound, and the hue and saturation of the resin film can be easily controlled. Note that, in the present disclosure, the total charges of the anions do not include charges derived from hydroxide ions.

[0103] As the anionic organic dye having absorption at wavelengths of 450 nm or more, a triarylmethane anion is preferred.

[0104] The anion may contain other anions in addition to the dye anion. The valence of the other anions is not limited. The valence of the other anions may be preferably 1 or more, more preferably 1 or more and 5 or less, and even more preferably 1 or more and 3 or less.

[0105] Examples of the other anions include carbonate ions, nitrate ions, phosphate ions, and bicarbonate ions. The other anions preferably include carbonate ions, and more preferably carbonate ions and nitrate ions. The coexistence of carbonate ions and nitrate ions with the dye anions is thought to stabilize the physical properties of the hydrotalcite-based compound due to physical and charge factors.

[0106] The major axis of the other anions may be, for example, 0.3 nm or more and 0.5 nm or less. When the major axis of the other anions is in this range, the dye anions can be stably present in the hydrotalcite compound.

[0107] The ratio of the charge derived from carbonate ions to the total charge of the anions may be 20% or more and 99.9% or less, 50% or more and 99% or less, or 60% or more and 98% or less. The ratio of the charge derived from carbonate ions to the total charge of the anions may be 20% or more, 50% or more, or 60% or more. Furthermore, the ratio of the charge derived from carbonate ions to the total charge of the anions may be 99.9% or less, 99% or less, or 98% or less. When the ratio of the charge derived from carbonate ions is within this range, the dye anions can be stably present in the hydrotalcite compound.

[0108] The ratio of the charge derived from nitrate ions to the total charge of the anions may be 0% or more and 30% or less, or 0% or more and 20% or less. When the ratio of the charge derived from carbonate ions is within this range, the dye anions can be present stably in the hydrotalcite-based compound. When the ratio of the charge derived from nitrate ions is within this range, the dye anions can be present stably in the hydrotalcite-based compound.

[0109] In one embodiment, the hydrotalcite compound may include two or more elementary layers each made of a double hydroxide containing a divalent metal and a trivalent metal, and one or more anions present between two adjacent elementary layers. Since the elementary layers are positively charged, the anions can be stabilized between the two adjacent elementary layers.

[0110] The divalent metal may be one or more types. The divalent metal preferably includes one or more types selected from the group consisting of Mg, Zn, Ca, Sr, Cu, Fe, Mn, Co, Ni, Sn, Pb, Cd, and Ba, and more preferably includes one or more types selected from Mg and Zn. When the divalent metal includes one or more types selected from Mg and Zn, the stability of the hydrotalcite compound is good.

[0111] The trivalent metal may be one or more types. The trivalent metal preferably includes one or more types selected from the group consisting of Al, Fe, Sc, Y, Ti, Cr, Fe, Al, Ga, In, and La, and more preferably includes one or more types selected from Al and Fe. When the trivalent metal includes one or more types selected from Al and Fe, the stability of the hydrotalcite compound is good.

[0112] The hydrotalcite compound preferably includes a compound represented by the following formula (I). Hereinafter, the compound represented by formula (I) will also be referred to as "compound (I)". [M1 ２＋ １－ｘ M2 ３＋ ｘ (OH) ２ ][(A1 ｎ－ ) ｘ／ｎ ・mH ２ O] ... (I) [In formula (I), M1 ２＋ represents one or more divalent metal ions, M2 ３＋ represents one or more trivalent metal ions, ｎ－ represents one or more kinds of n-valent anions, and the one or more kinds of n-valent anions include at least an anion having absorption at a wavelength of 450 nm or more, m is 0 or more and less than 1, n is 1 or more and less than 5, and x is more than 0 and less than 0.5.

[0113] When the hydrotalcite-based compound contains the compound represented by formula (I), yellowing of the resin film is further suppressed, and it may become easier to suppress the degree of haze to a lower level.

[0114] M1 ２＋ represents one or more divalent metal ions. ２＋ is Mg ２＋ , Zn ２＋ , Ca ２＋ , Sr ２＋ , Cu ２＋ , Fe ２＋ , Mn ２＋ , Co ２＋ , Ni ２＋ , Sn ２＋, Pb ２＋ , Cd ２＋ and Ba ２＋ Preferably, the composition contains one or more selected from the group consisting of Mg ２＋ and Zn ２＋ It is more preferable that the compound contains one or more selected from the following: ２＋ However, Mg ２＋ and Zn ２＋ By including one or more selected from the above, the stability of the compound represented by formula (I) can be improved.

[0115] M2 ３＋ represents one or more trivalent metal ions. ３＋ is Al ３＋ , Fe ３＋ , Sc ３＋ , Y ３＋ , Ti ３＋ , Cr ３＋ , Fe ３＋ , Al ３＋ , Ga ３＋ , In ３＋ and La ３＋ It is preferable that the composition contains one or more selected from the group consisting of Al ３＋ and Fe ３＋ It is more preferable that the compound contains one or more selected from the following: ３＋ But, Al ３＋ and Fe ３＋ By including one or more selected from the above, the stability of the compound represented by formula (I) can be improved.

[0116] A1 ｎ－ represents one or more kinds of n-valent anions, and the one or more kinds of n-valent anions include at least an anion having absorption at a wavelength of 450 nm or more. The anion having absorption at a wavelength of 450 nm or more has the same meaning as the above-mentioned anion having absorption at a wavelength of 450 nm or more.

[0117] The anion having absorption at wavelengths of 450 nm or more is preferably a triarylmethane anion.

[0118] Furthermore, the anion having absorption at wavelengths of 450 nm or more preferably includes a low-toxicity anion. This allows for the provision of a resin film that is highly safe for the human body, and in particular, a resin film that complies with the Food Sanitation Act or the Pharmaceutical Affairs Act. As the low-toxicity anion having absorption at wavelengths of 450 nm or more, a blue or purple dye is preferred, the blue dye is more preferred, and Brilliant Blue FCF is even more preferred.

[0119] (Y×n1) / x is preferably 0.1% or more and 20% or less, more preferably 2% or more and 18% or less, and even more preferably 5% or more and 18% or less. (Y×n1) / x is preferably 0.1% or more, more preferably 2% or more, and even more preferably 5% or more. Furthermore, (Y×n1) / x is preferably 20% or less, more preferably 18% or less, and even more preferably 18% or less. When (Y×n1) / x is within this range, the dye anion can be stably present in the hydrotalcite compound, and the hue and saturation of the resin film can be easily controlled.

[0120] The one or more n-valent anions may contain other anions in addition to the dye anions. The other anions have the same meaning as the other anions described above, and specific examples thereof include carbonate ions, nitrate ions, phosphate ions, and bicarbonate ions. The other anions preferably contain carbonate ions, and more preferably contain carbonate ions and nitrate ions.

[0121] m is 0 or more and less than 1, and preferably 0 or more and 0.5 or less. n is 1 or more and 5 or less, and preferably 1 or more and 3 or less. When two or more types of anions are contained, n may be calculated as a weighted average based on the charge and molar content of each anion. x is more than 0 and less than 0.5, and preferably 0.1 or more and 0.4 or less. x is more than 0, preferably 0.1 or more and less than 0.5, and preferably 0.4 or less.

[0122] The content of the compound (I) is preferably 70% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, and even more preferably 90% by mass or more and 100% by mass or less, based on 100% by mass of the total of the hydrotalcite-type compounds.

[0123] The content of the hydrotalcite-based compound is preferably 0.001% by mass or more and 0.1% by mass or less, more preferably 0.003% by mass or more and 0.07% by mass or less, and even more preferably 0.005% by mass or more and 0.05% by mass or less, based on 100% by mass of the total resin film. The content of the hydrotalcite-based compound is preferably 0.001% by mass or more, more preferably 0.003% by mass or more, and even more preferably 0.005% by mass or more, based on 100% by mass of the total resin film. Furthermore, the content of the hydrotalcite-based compound is preferably 0.1% by mass or less, more preferably 0.07% by mass or less, and even more preferably 0.05% by mass or less, based on 100% by mass of the total resin film. When the content of the hydrotalcite-based compound is within this range, the resin film can achieve both high hue and saturation and low haze.

[0124] The hydrotalcite-based compound preferably includes a hydrotalcite-based compound that has been surface-treated with a higher fatty acid. Hydrotalcite-based compounds that have been surface-treated with a higher fatty acid have good dispersibility in resins. While not limited to a specific theory, the reason why hydrotalcite-based compounds that have been surface-treated with a higher fatty acid have good dispersibility in resins is thought to be as follows: Higher fatty acids typically have both hydrophobic and hydrophilic moieties. Because hydrotalcite-based compounds are highly hydrophilic, it is thought that the hydrophilic moieties undergo hydrophilic interactions with the surface of the hydrotalcite-based compound, with the hydrophobic moieties surrounding them. As a result, it is thought that hydrotalcite-based compounds that have been surface-treated with a higher fatty acid have a high affinity for highly hydrophobic resins, improving wettability with the resin and increasing repulsion between the hydrotalcite-based compounds.

[0125] Furthermore, for reasons unknown, hydrotalcite surface-treated with a higher fatty acid can contain more dye anions than non-surface-treated hydrotalcite. Therefore, it is believed that the use of a hydrotalcite-type compound surface-treated with a higher fatty acid makes it easier to control the appearance of a resin film, particularly the hue, saturation, and haze of the resin film.

[0126] As the higher fatty acid, any of the higher fatty acids described in the first production method can be used. In one aspect, the higher fatty acid is preferably a saturated higher fatty acid, more preferably stearic acid, erucic acid, palmitic acid, lauric acid, or behenic acid. The higher fatty acid preferably includes a plant-derived higher fatty acid.

[0127] The proportion of the higher fatty acid is preferably 0.1% by mass or more and 10.0% by mass or less, more preferably 0.5% by mass or more and 8.0% by mass or less, and even more preferably 1.0% by mass or more and 5.0% by mass or less, based on a total of 100% by mass of the hydrotalcite-based compounds surface-treated with the higher fatty acid. The proportion of the higher fatty acid is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, based on a total of 100% by mass of the hydrotalcite-based compounds surface-treated with the higher fatty acid. The proportion of the higher fatty acid is preferably 10.0% by mass or less, more preferably 8.0% by mass or less, and even more preferably 5.0% by mass or less, based on a total of 100% by mass of the hydrotalcite-based compounds surface-treated with the higher fatty acid. Having the proportion of the higher fatty acid within this range can improve the dispersibility of the resulting hydrotalcite-based compound in the resin and facilitate increasing the content of dye anions.

[0128] The surface treatment with a higher fatty acid can be carried out by contacting a hydrotalcite compound with an alkali metal salt of a higher fatty acid. When contacting the hydrotalcite compound with the alkali metal salt of a higher fatty acid, a dispersion medium such as water may be present. Alternatively, the hydrotalcite compound may be emulsified in advance in a dispersion medium, and then the hydrotalcite compound may be contacted with the alkali metal salt of a higher fatty acid.

[0129] The content of the hydrotalcite-type compound surface-treated with a higher fatty acid is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, but not more than 100% by mass, based on a total of 100% by mass of the hydrotalcite-type compounds. This allows for good dispersibility of the hydrotalcite-type compound in the resin, and the appearance of the resulting resin film can be improved. Furthermore, by including both a hydrotalcite-type compound surface-treated with a higher fatty acid and a hydrotalcite not surface-treated with a higher fatty acid, it can be easier to control the hue and saturation of the resin film.

[0130] The hydrotalcite-based compound is preferably in particulate form. The average secondary particle diameter of the hydrotalcite-based compound is preferably 0.1 μm or more and 5 μm or less, more preferably 0.15 μm or more and 2 μm or less, and even more preferably 0.2 μm or more and 1.5 μm or less. The average secondary particle diameter of the hydrotalcite-based compound is preferably 0.1 μm or more, more preferably 0.15 μm or more, and even more preferably 0.2 μm or more. The average secondary particle diameter of the hydrotalcite-based compound is preferably 5 μm or less, more preferably 2 μm or less, and even more preferably 1.5 μm or less. When the average secondary particle diameter of the hydrotalcite-based compound is within this range, the haze of the resulting resin film can be suppressed to a low level.

[0131] The BET specific surface area of ​​the hydrotalcite compound is preferably 12 m ２ / g or more 20m ２ / g or less, more preferably 14m ２ / g or more 18m ２The BET specific surface area of ​​the hydrotalcite compound is preferably 12 m ２ / g or more, more preferably 14m ２ / g or more, preferably 120m ２ / g or less, more preferably 18m ２ / g or less.

[0132] In one embodiment, the hydrotalcite-based compound can be produced using a hydrotalcite containing carbonate ions as a starting material. Such a production method can include a step of exchanging carbonate ions with nitrate ions and a step of exchanging nitrate ions with dye anions. While not intended to be limited to a particular theory, it is believed that nitrate ions are more likely to increase the distance between the basic layers of hydrotalcite than carbonate ions. Therefore, it is believed that exchanging carbonate ions with nitrate ions facilitates the exchange with dye anions. Note that when a hydrotalcite containing carbonate ions is heated with CO ３ It is also called type hydrotalcite.

[0133] The hydrotalcite containing carbonate ions may be calcined before ion exchange with nitrate ions. Calcining the hydrotalcite can eliminate hydration water and hydroxyl groups, resulting in an oxide having a positively charged surface. It is believed that the positive charge on the surface of the resulting oxide makes it easier for dye anions to adsorb to the surface of the oxide. For example, [M1 ２＋ １－ｘ M2 ３＋ ｘ (OH) ２ ][(CO ３ ２－ ) ｘ／２ ・mH ２ When the hydrotalcite represented by the formula [O] is calcined, M1 ２＋ １－ｘ M2 ３＋ ｘ O １＋０．５ｘ In the above formula, an oxide represented by the formula: ２＋ represents one or more divalent metal ions, M2 ３＋represents one or more trivalent metal ions, m is 0 or more and less than 1, and x is more than 0 and less than 0.5. The BET specific surface area of ​​the oxide is 50 m ２ / g or more 300m ２ / g or less, which is larger than the general BET specific surface area of ​​hydrotalcite.

[0134] The oxides can undergo a hydration reaction in water or hot water to produce hydrotalcite compounds, in which case the dye anions can be incorporated between the base layers.

[0135] The temperature during the firing may be preferably 300° C. or higher and 900° C. or lower, more preferably 350° C. or higher and 800° C. or lower, and even more preferably 400° C. or higher and 700° C. or lower. The temperature during the firing may be preferably 300° C. or higher, more preferably 350° C. or higher, and even more preferably 400° C. or higher, and preferably 900° C. or lower, more preferably 800° C. or lower, and even more preferably 700° C. or lower.

[0136] The carbonate ion-containing hydrotalcite can be produced by a production method including the steps of: mixing an aqueous solution of a water-soluble metal salt of a divalent metal, an aqueous solution of a water-soluble metal salt of a trivalent metal, an alkali metal hydroxide, and an aqueous solution of an alkali metal carbonate in an aqueous medium to obtain a mixed solution; maintaining the pH of the mixed solution at 8 or higher to coprecipitate a hydrotalcite precursor; and washing the hydrotalcite precursor with the alkali metal carbonate aqueous solution to obtain a carbonate ion-containing hydrotalcite compound.

[0137] The carbonate ion-containing hydrotalcite may further be subjected to hydrothermal treatment. Hydrothermal treatment can suppress crystal growth and aggregation of the hydrotalcite. The hydrothermal treatment can be carried out using an autoclave. The temperature of the hydrothermal treatment is preferably 100°C or higher, more preferably 120 to 200°C, and the hydrothermal treatment time is preferably 10 hours or longer. The carbonate ion-containing hydrotalcite may be dehydrated, dried, pulverized, and classified as necessary.

[0138] As the water-soluble metal salt of the divalent metal, for example, magnesium chloride can be used. As the water-soluble metal salt of the trivalent metal, for example, aluminum sulfate can be used. As the alkali metal hydroxide, for example, sodium hydroxide can be used. As the alkali metal carbonate, for example, sodium carbonate can be used. The pH range of the mixed solution is preferably 9 to 11.

[0139] The hydrotalcite-based compounds used in the present disclosure are not limited to those produced by such a production method.

[0140] The resin film of the present disclosure contains a hydrotalcite-type compound and a resin, and in a preferred embodiment, the hydrotalcite-type compound is dispersed in the resin.

[0141] The resin film preferably further contains a compound represented by the following formula (II). Hereinafter, the compound represented by formula (II) will also be referred to as "compound (II)". [M3 ２＋ １－ｙ M4 ３＋ ｙ (OH) ２ ][(A2 ｑ－ ) ｙ／ｑ pH ２ O]...(II) [In formula (II), M3 ２＋ is Mg ２＋ , Zn ２＋ , Ca ２＋ , Sr ２＋ , Cu ２＋ , Fe ２＋ , Mn ２＋ , Co ２＋ , Ni ２＋ , Sn ２＋ , Pb ２＋ , Cd ２＋ and Ba ２＋ M4 represents one or more metal ions selected from the group consisting of ３＋ is Al ３＋ and Fe ３＋ A2 represents one or more metal ions selected from ｑ－represents one or more q-valent anions, p is 0 or more and less than 1, q is 1 or more and less than 5, and y is more than 0 and less than 0.5.

[0142] The compound (II) can adsorb halogen atoms and exhibit properties as a stabilizer for resins. Therefore, by further containing the compound (II) in a resin film, it is possible to improve the stability of the resin film while maintaining a good appearance of the resin film. The compound (II) is broadly classified as hydrotalcite.

[0143] M3 ２＋ is Mg ２＋ , Zn ２＋ , Ca ２＋ , Sr ２＋ , Cu ２＋ , Fe ２＋ , Mn ２＋ , Co ２＋ , Ni ２＋ , Sn ２＋ , Pb ２＋ , Cd ２＋ and Ba ２＋ M3 represents one or more metal ions selected from the group consisting of ２＋ is Mg ２＋ and Zn ２＋ It is preferable that the compound contains one or more selected from the following: ２＋ However, Mg ２＋ and Zn ２＋ By including one or more selected from the above, the stability of the compound represented by formula (II) can be improved.

[0144] M4 ３＋ is Al ３＋ and Fe ３＋ represents one or more metal ions selected from the following:

[0145] A2 ｑ－ represents one or more q-valent anions. Examples of the q-valent anions include carbonate ions, nitrate ions, phosphate ions, and bicarbonate ions. The q-valent anions preferably include carbonate ions, and more preferably include carbonate ions and nitrate ions.

[0146] p is 0 or more and less than 1, and preferably 0 or more and 0.5 or less. q is 1 or more and 5 or less, and preferably 1 or more and 3 or less. When two or more types of anions are contained, q may be calculated as a weighted average based on the charge and molar content of each anion. y is more than 0 and less than 0.5, and preferably 0.1 or more and 0.4 or less.

[0147] The compound (II) may or may not be surface-treated with the higher fatty acid. In one embodiment, the compound (II) is preferably surface-treated with the higher fatty acid.

[0148] The compound (II) is preferably in a particulate form. The average secondary particle diameter of the compound (II) is preferably 0.1 μm or more and 1 μm or less, more preferably 0.3 μm or more and 0.5 μm or less. The compound (II) is preferably in a particulate form. The average secondary particle diameter of the compound (II) is preferably 0.1 μm or more, more preferably 0.3 μm or more, and preferably 1 μm or less, more preferably 0.5 μm or less. When the average secondary particle diameter of the compound (II) is in this range, it can be easy to reduce the haze of the obtained resin film.

[0149] The content of compound (II) is preferably 0 parts by mass or more and 20 parts by mass or less relative to 1 part by mass of the hydrotalcite-based compound. In one aspect, the content of compound (II) is preferably 1 part by mass or more and 15 parts by mass or less, more preferably 1 part by mass or more and 10 parts by mass or less, relative to 1 part by mass of the hydrotalcite-based compound. In another aspect, the content of compound (II) may be 0 parts by mass relative to 1 part by mass of the hydrotalcite-based compound.

[0150] The total content of the hydrotalcite-based compound and compound (II) is, based on 100% by mass of the resin film, preferably 0.001% by mass or more and 0.5% by mass or less, more preferably 0.005% by mass or more and 0.1% by mass or less, and even more preferably 0.01% by mass or more and 0.07% by mass or less. The total content of the hydrotalcite-based compound and compound (II) is, based on 100% by mass of the resin film, preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more. Furthermore, the total content of the hydrotalcite-based compound and compound (II) is, based on 100% by mass of the resin film, preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.07% by mass or less. This allows the resin film to have both high hue and saturation and low haze, and the stability of the resin film can be improved.

[0151] The compound (II) is preferably dispersed in a resin.

[0152] The resin film of the present disclosure may contain, in addition to the hydrotalcite-type compound and compound (II), a compound classified as hydrotalcite in a broad sense. In the resin film of the present disclosure, the total content of the hydrotalcite-type compound and compound (II) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and 100% by mass or less, based on 100% by mass of the total compounds classified as hydrotalcite.

[0153] The compound classified as hydrotalcite in the broad sense is preferably dispersed in a resin.

[0154] The resin may be any resin that can be used in resin films. Examples of the resin include thermoplastic resins such as polyolefin resins, polyamide resins, polyester resins, polyvinyl chloride, polystyrene resins, polyvinyl acetate, and urethane resins. A preferred example of the resin is a polyolefin resin. Polyolefin resins have mechanical properties such as tensile strength, tear strength, and impact strength, as well as properties such as waterproofness, moisture resistance, and chemical resistance, and are therefore suitable for use in resin films. Furthermore, polyolefin resins are lightweight, have excellent light transmittance, breathability, and heat sealability. Therefore, by including a polyolefin resin, a resin film suitable for, for example, food packaging can be provided. Furthermore, polyolefin resins can sometimes yellow during processing and storage due to the effects of heat, light, oxygen, and the like. However, the resin film of the present disclosure contains a specific hydrotalcite-type compound, making it easy to counteract such yellowing.

[0155] Examples of the polyolefin resin include polymers of olefin compounds and copolymers of olefin compounds with other ethylenic monomers. Preferred examples of the olefin compounds include olefin compounds having 2 to 6 carbon atoms, such as ethylene, propylene, 1-butene, and 4-methyl-1-pentene. Examples of the other ethylenic monomers include (meth)acrylic acid esters, such as vinyl acetate, (meth)acrylic acid, methyl (meth)acrylate, and ethyl (meth)acrylate.

[0156] Specific examples of the polyolefin resin include polyethylene; polypropylene; polypropylene; polybutene-1; poly-4-methylpentene-1; copolymers of ethylene and an α-olefin other than ethylene; copolymers of ethylene and ethyl acrylate or methyl acrylate; copolymers of propylene and an α-olefin other than propylene; and copolymers of ethylene, propylene, 1-butene or 4-methyl-1-pentene with vinyl acetate.

[0157] The resin may be a crystalline resin or an amorphous resin, and preferably a crystalline resin. Since the resin film of the present disclosure contains a specific hydrotalcite compound, even if the resin film contains a crystalline resin, crystal nucleation can be suppressed, and as a result, warping of the resin film and deterioration of mechanical properties due to crystallization can be suppressed.

[0158] The crystalline resin has a crystalline melting point of preferably 100°C or higher and 400°C or lower, more preferably 120°C or higher and 350°C or lower, and even more preferably 130°C or higher and 280°C or lower. The crystalline melting point of the crystalline resin is preferably 100°C or higher, more preferably 120°C or higher, and even more preferably 130°C or higher, and is preferably 400°C or lower, more preferably 350°C or lower, and even more preferably 280°C or lower. Because the resin film of the present disclosure contains a specific hydrotalcite-type compound, it has good thermal stability and is suppressed from fading, yellowing, and the like. Therefore, even if the crystalline melting point of the crystalline resin is within the above range, a resin film with good appearance can be provided. The crystalline melting point of the crystalline resin can be measured by differential scanning calorimetry.

[0159] The resin film of the present disclosure may contain other additives in addition to the hydrotalcite compound, the compound represented by formula (II) used as needed, and the resin. Such other additives include antistatic agents, pigments, matting agents, heat stabilizers, light stabilizers, flame retardants, antibacterial agents, lubricants, plasticizers, softeners, antioxidants, and UV absorbers. Phosphorus-based antioxidants and phenol-based antioxidants are preferred as the antioxidants.

[0160] According to the studies of the inventors of the present disclosure, when the compound represented by formula (II) is used in combination with a phenolic antioxidant, the resin film tends to become more yellowish. However, the resin film of the present disclosure uses the hydrotalcite compound, which can counteract such discoloration of the resin film. As a result, a resin film with good appearance can be obtained.

[0161] The content of other additives may be preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.1% by mass or more and 3% by mass or less, based on 100% by mass of the total resin film. The content of other additives may be preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, based on 100% by mass of the total resin film.

[0162] The thickness of the resin film is preferably 1 μm or more and 1,000 μm or less, more preferably 3 μm or more and 400 μm or less, and even more preferably 5 μm or more and 200 μm or less. The thickness of the resin film is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more, and is preferably 1,000 μm or less, more preferably 400 μm or less, and even more preferably 200 μm or less. When the thickness of the resin film is large, yellowing of the resin film tends to be accentuated, and in such cases, the effect of controlling the appearance of the resin film by the hydrotalcite-based compound is more easily exhibited.

[0163] In the JIS standard, a plastic membrane with a thickness of less than 250 μm is called a film, and a thin plastic plate with a thickness of 250 μm or more is called a sheet, but in this disclosure, those with a thickness of 250 μm or more are also included in the technical scope of resin films.

[0164] The resin film can be produced by a production method such as an extrusion molding method, a solution casting method, or a calendar molding method. In one embodiment, the resin film is preferably produced by an extrusion molding method. When producing the resin film, pellets containing a hydrotalcite compound and the resin may be produced in advance, and then the pellets may be used to produce the resin film.

[0165] The resin film of the present disclosure has good appearance and mechanical properties, and can be used for a variety of industrial applications, including food packaging, for example, construction materials, home appliances, automobiles, electronic devices, daily necessities, medical care, and agriculture.

[0166] The present invention will be described in more detail with reference to the following examples, but the present disclosure is not limited thereto.

[0167] Production example 1: CO ３ 36 parts by mass of an 11.5 mass% aqueous magnesium chloride solution, 13 parts by mass of a 26.2 mass% aqueous aluminum sulfate solution, 43 parts by mass of a 12.3 mass% aqueous sodium hydroxide solution, and 10 parts by mass of a 7.4 mass% aqueous sodium carbonate solution were mixed in an aqueous medium to obtain a mixed solution. Next, the pH of the mixed solution was maintained at 8 or higher using sodium hydroxide to cause coprecipitating. Thereafter, the coprecipitate was washed with an aqueous sodium carbonate solution and then with water to obtain hydrotalcite in which the interlayer anion is carbonate ion, i.e., CO ３ The synthesized hydrotalcite compound was subjected to hydrothermal treatment in an autoclave at 100°C or higher for 10 hours or more. After that, it was subjected to processes such as dehydration, drying, pulverization and classification, and then CO ３ A powder of type hydrotalcite was obtained. ３ The hydrotalcite powder has the chemical formula Mg ４．３ Al ２ (OH)12.6CO ３ ・3.3H ２ The compound was represented by CO. ３ The BET specific surface area of ​​the hydrotalcite powder is 14 m ２ / g, and the average secondary particle diameter was 0.38 μm.

[0168] Example 1-1: Method for producing hydrotalcite-based compounds CO produced in Production Example 1 ３ 61.5 g of the hydrotalcite was emulsified in 1.4 L of warm water. The hydrotalcite was surface-treated using sodium stearate. Next, 87.5 mL of a 3.5% by mass aqueous solution of nitric acid was added, and the mixture was stirred and maintained at approximately 80°C for 30 minutes. This reaction caused the hydrotalcite to undergo ion exchange, with some of the carbonate ions being replaced by nitrate ions. Then, 19.77 g of dye was added, and the mixture was again stirred and maintained at approximately 80°C for 30 minutes. The mixture was then filtered under reduced pressure, washed, and dried (60°C, 4 hours).

[0169] The amount of dye contained in the washing solution was quantified using ultraviolet-visible spectroscopy, and the amount of dye introduced into the powder was calculated by subtracting it from the added amount. As a result, it was found that 3.18 g of dye, or approximately 3.2 mol% of the dye relative to the hydrotalcite, had been introduced into the powder. FT-RI analysis also confirmed the presence of sulfo groups contained in the dye. The BET specific surface area was 15.6 m ２ / g.

[0170] Example 1-2 CO produced in Production Example 1 ３ 15 g of type hydrotalcite was emulsified in 0.6 L of warm water. 0.5 g of stearic acid was dissolved in an equivalent amount of aqueous sodium hydroxide solution and added, and the mixture was maintained at 80°C for 30 minutes to perform a surface treatment. Next, 57.7 mL of a 1.1 mol / L aqueous nitric acid solution was added so that the pH was in the range of 3.1 to 3.6, and the mixture was maintained with stirring at approximately 80°C for 30 minutes. This reaction replaced some of the carbonate ions in the hydrotalcite with nitrate ions. Thereafter, 1.21 g of dye was added, and the mixture was again maintained with stirring at approximately 80°C for 30 minutes. The mixture was then filtered under reduced pressure, washed, and dried (60°C, 4 hours).

[0171] The amount of dye contained in the washing solution was quantified using ultraviolet-visible spectroscopy, and the amount of dye introduced into the powder was calculated by subtracting it from the amount added. As a result, it was found that approximately 8.05 mol% of the dye was introduced into the powder using 3.18 g of dye and hydrotalcite. FT-RI analysis also confirmed the presence of sulfo groups in the dye. The BET specific surface area was 16.1 m ２ / g.

[0172] Comparative Example 1-1 CO produced in Production Example 1 ３ 5.00 g of dye was added to 50 g of hydrotalcite, and the mixture was stirred and maintained at approximately 80°C for 30 minutes to allow the dye to be retained. The resulting mixture was then emulsified in 1 L of warm water. 1.86 g of stearic acid was dissolved in an equivalent amount of aqueous sodium hydroxide solution and added, and the mixture was maintained at 80°C for 3 minutes to allow for surface treatment. The mixture was then filtered under reduced pressure, washed, and dried (60°C, 4 hours).

[0173] The amount of dye contained in the washing solution was quantified by ultraviolet-visible spectroscopy, and the amount of dye incorporated into the powder was calculated by subtracting it from the amount added. As a result, it was confirmed that the amount of dye incorporated into the hydrotalcite was approximately 0.15 mol%. The BET specific surface area was 12.4 m ２ / g.

[0174] Comparative Example 1-2 CO produced in Production Example 1 ３ 25 g of type hydrotalcite was emulsified in 1 L of warm water. 0.93 g of stearic acid was dissolved in an equivalent amount of aqueous sodium hydroxide solution and added, and the mixture was maintained at 80°C for 30 minutes to perform a surface treatment. Next, 2.53 g of dye was added, and the mixture was again maintained at approximately 80°C for 30 minutes with stirring to maintain the dye. The mixture was then filtered under reduced pressure, washed, and dried (60°C, 4 hours).

[0175] The amount of dye contained in the washing solution was quantified by ultraviolet-visible spectroscopy, and the amount of dye incorporated into the powder was calculated by subtracting it from the amount added. As a result, it was confirmed that the amount of dye incorporated into the hydrotalcite was approximately 0.21 mol%. The BET specific surface area was 12.6 m ２ / g

[0176] Comparative Example 1-3 CO produced in Production Example 1 ３ 25 g of type hydrotalcite was emulsified in 1 L of warm water. 0.47 g of stearic acid was dissolved in an equivalent amount of aqueous sodium hydroxide solution and added, and the mixture was maintained at 80°C for 30 minutes to perform a surface treatment. Next, 2.51 g of dye was added, and the mixture was again maintained at approximately 80°C with stirring for 30 minutes to perform dye retention. The mixture was then filtered under reduced pressure, washed, and dried (60°C for 4 hours). The mixture was then filtered under reduced pressure, washed, and dried (60°C for 4 hours).

[0177] The amount of dye contained in the washing solution was quantified by ultraviolet-visible spectroscopy, and the amount of dye incorporated into the powder was calculated by subtracting it from the amount added. As a result, it was confirmed that the amount of dye incorporated into the hydrotalcite was approximately 0.46 mol%. The BET specific surface area was 12.3 m ２ / g.

[0178] Comparative Example 1-4 CO produced in Production Example 1 ３To 61.5 g of the hydrotalcite, 87.5 mL of a 3.5 mass % aqueous solution of nitric acid was added, and the mixture was stirred and maintained at about 80° C. for 30 minutes. ３ － Some of the ions are NO ３ ２－ Then, 18.22 g of dye was added, and the mixture was stirred and maintained at about 80°C for 30 minutes to retain the dye.The mixture was then filtered under reduced pressure, washed, and dried (60°C, 4 hours).

[0179] The amount of dye contained in the washing solution was quantified by ultraviolet-visible spectroscopy, and the amount of dye incorporated into the powder was calculated by subtracting it from the added amount. As a result, it was confirmed that the amount of dye incorporated into the hydrotalcite was approximately 0.51 mol%. The BET specific surface area was 19.9 m ２ / g.

[0180] Examples 2-1 to 2-4, Comparative Examples 2-1 to 2-3 Polypropylene resin (homopolypropylene resin, MFR 2.0 g / 10 min, 190°C), antioxidant 1 (phenolic antioxidant, manufactured by BASF, product name: IRGANOX 1010: 500 ppm), antioxidant 2 (phosphorus-based antioxidant, manufactured by BASF, product name: IRGAFOS 168: 1,000 ppm), acid neutralizer (calcium stearate), halogen adsorbent (CO ３ Type hydrotalcite, manufactured by Kyowa Chemical Industry Co., Ltd. Product name: DHT (registered trademark)-4A: BET specific surface area: 11 m ２ / g, average secondary particle size: 0.37 μm, chemical formula Mg ４．３ Al ２ (OH)12.6CO ３ ・3.3H ２ The hydrotalcite compound prepared in Example 1-1 and a blue pigment (a copper phthalocyanine organic pigment, manufactured by BASF, product name: Microlen (registered trademark) Blue) were mixed in the amounts shown in Table 1 and kneaded in a twin-screw extruder at 220°C to produce approximately 1,500 g of pellets. The pellets were then molded into a film having a thickness of approximately 30 µm in a single-screw extruder equipped with a T-die.

[0181] The obtained film was subjected to measurement of yellowing and transparency, and a tensile test. Separately, pellets were produced by repeating kneading using a single screw extruder once, three times, or five times, and the produced pellets were recovered, and the melt flow rate (MFR) was measured. Furthermore, the film was press-molded and the yellowing was measured.

[0182]

[0183] [Measurement of Yellowing Degree] Using a colorimeter (Color meter ZE 6000, manufactured by Nippon Denshoku Industries Co., Ltd.), spectroscopic measurement of reflected light was carried out using a halogen lamp as a light source, and the L value, a value, b value, yellow index (YI), and whiteness (W Lab) in the Lab color system were measured.

[0184] [Measurement of Haze Degree] Haze was measured in accordance with JIS K 7136 using a haze meter (Haze meter NDH 4000, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0185] [Tensile Test] A tensile test was performed using a tensile tester (Instron, 5967) at a temperature of 23°C and a pulling speed of 500 mm / min to measure the tensile strength and maximum elongation. The tensile test was performed in the length direction (MD) and width direction (TD) of the resin film. The length direction of the resin film refers to the extrusion direction of the resin film, and the width direction refers to the direction perpendicular to the extrusion direction.

[0186] [Measurement of Crystallization Temperature] Using a thermogravimetric differential thermal analyzer (STA Regulus, manufactured by Netsch Japan), the crystallization temperature was measured with a sample weight of 5 mg, a heating rate of 10°C / min, and a nitrogen flow rate of 50 mL / min.

[0187] [Measurement of Melt Flow Rate (MFR)] The melt flow rate was measured using a melt flow rate tester (Melt indexer TM21-F2A, manufactured by Tateyama Scientific Co., Ltd.) in accordance with JIS K 6922-1 (1997).

[0188] The results are shown in Table 2.

[0189]

[0190] Examples 2-1 to 2-4 are examples of the present disclosure, and the resulting resin films were inhibited from yellowing, had low haze, high transparency, and high tensile strength. Comparative Examples 2-1 and 2-2 are examples that did not contain a hydrotalcite compound, and the resulting resin films had large b values ​​and yellow indexes, and yellowing occurred. Comparative Example 2-3 is an example in which a pigment was used as the blue colorant, and the resulting resin film had high haze and high haze. Furthermore, the resin film obtained in Comparative Example 2-3 had particularly low tensile strength and elongation in the longitudinal direction, and thus had reduced mechanical properties.

[0191] Separately, kneading using a single screw extruder was repeated once, three times, or five times to produce pellets, and the produced pellets were recovered and further press-molded to measure the yellowing degree. The results are shown in Table 3.

[0192]

[0193] Examples 2-1 to 2-4 are examples of the present disclosure, and it was confirmed that the resin film had low yellowing and excellent heat resistance even when the number of kneading cycles was increased. Comparative Example 2-1 is an example that did not contain a hydrotalcite-type compound, and it was confirmed that the resulting resin film had a large b value and yellow index, and that yellowing became more pronounced as the number of kneading cycles increased. Comparative Example 2-2 is an example that did not contain a hydrotalcite-type compound and used a halogen adsorbent, and although the progression of yellowing with the number of kneading cycles was not significant, yellowing was observed regardless of the number of kneading cycles. Comparative Example 2-3 is an example that used a pigment as a blue colorant, and although the progression of yellowing with the number of kneading cycles was not significant, it was suggested that the brightness was low and the degree of haze was high regardless of the number of kneading cycles.

[0194] The resin film of the present disclosure has a good appearance and can be used for various industrial purposes, including food packaging.

Claims

1. A hydrotalcite compound represented by the following formula (I), [M1 ２＋ １－ｘ M2 ３＋ ｘ (OH) ２ ][(A1 ｎ－ ) ｘ／ｎ ・mH ２ O] ... (I) [In formula (I), M1 ２＋ represents one or more divalent metal ions, M2 ３＋ This represents one or more trivalent metal ions, A1 ｎ－ This represents one or more n-valent anions, and these one or more n-valent anions include at least one organic dye anion having absorption at a wavelength of 450 nm or higher. m is greater than or equal to 0 and less than 1. n is between 1 and 5, x is greater than 0 and less than 0.

5. The anion further comprises carbonate ions and nitrate ions. Hydrotalcite compounds that are surface-treated with higher fatty acids.

2. M1 ２＋ Mg ２＋ and Zn ２＋ Includes one or more selected from M2 ３＋ Al ３＋ and Fe ３＋ A hydrotalcite compound according to claim 1, comprising one or more selected from the above.

3. The hydrotalcite compound according to claim 1, wherein the organic dye of anions having absorption at a wavelength of 450 nm or higher comprises one or more selected from triarylmethane anions, naphthoquinone imine anions, anthraquinone anions, xanthene anions, azo anions, quinoline anions, indigo anions, and perylene anions.

4. The hydrotalcite compound according to claim 1, wherein the ratio of the total charge derived from the organic dye of the anion having absorption at a wavelength of 450 nm or more to the total charge of the anion is 0.1% or more and 20% or less.

5. A resin film comprising a hydrotalcite compound according to any one of claims 1 to 4 and a resin, wherein the resin includes a polyolefin resin.

6. The aforementioned polyolefin resin is polyethylene; polypropylene; Polybutene-1; Poly-4-methylpentene-1; Copolymers of ethylene and α-olefins other than polyethylene; A copolymer of ethylene and ethyl acrylate or methyl acrylate; Copolymers of propylene and α-olefins other than polypropylene; and, Copolymers of ethylene, propylene, 1-butene or 4-methyl-1-pentene, and vinyl acetate; The resin film according to claim 5, comprising one or more selected from the group consisting of the following.

7. The resin film according to claim 5, wherein the thickness of the resin film is 1 μm or more and 1,000 μm or less.

8. The resin film according to claim 5, wherein the content of the hydrotalcite compound contained in the resin film is 0.001% by mass or more and 0.1% by mass or less of the total mass of the resin film.

9. The resin film according to claim 5, further comprising hydrotalcite represented by the following formula (II). [M3 ２＋ １－ｙ M4 ３＋ ｙ (OH) ２ ][(A2 ｑ－ ) ｙ／ｑ ・pH ２ O ... (II) [In formula (II), M3 ２＋ Mg ２＋ , Zn ２＋ Ca ２＋ , Sr ２＋ ,Cd ２＋ Fe ２＋ Mn ２＋ Co ２＋ Ni ２＋ Sn ２＋ Pb ２＋ , Cd ２＋ and Ba ２＋ This represents one or more metal ions selected from the group consisting of the following: M4 ３＋ Al ３＋ and Fe ３＋ Represents one or more metal ions selected from, A2 ｑ－ This represents one or more q-valent anions, p is greater than or equal to 0 and less than 1. q is between 1 and 5, y is greater than 0 and less than 0.

5.

10. A surface treatment step of coating the surface of hydrotalcite containing a first anion with a higher fatty acid or a salt thereof, A substitution step is performed after the surface treatment step, in which at least a portion of the first anion is replaced with a second anion having a lower valency than the first anion. A method for producing hydrotalcite compounds, comprising the steps of: after the substitution step, a holding step of holding an organic dye having absorption at a wavelength of 450 nm or higher in the hydrotalcite.

11. The method for producing hydrotalcite compounds according to claim 10, wherein the substitution step is carried out in a pH range of 2 to 5.

12. A method for producing hydrotalcite compounds according to claim 10 or 11, wherein the first anion comprises a carbonate ion and / or a sulfate ion, and the second anion comprises a nitrate ion.