Resin composition, laminate, industrial film, pipe, masterbatch, and method for manufacturing resin composition

Abstract

To provide a resin composition containing EVOH which has such weather resistance as to maintain impact strength and light transmittance even after long-term outdoor use and can suppress coloring of an obtained film, a laminate, an industrial film, and a pipe, and a production method for the resin composition and a master batch used in the production method.SOLUTION: A resin composition contains EVOH (A) having an ethylene unit content of 20-60 mol%, a hindered amine-based compound (B) which has a 2,2,6,6-tetraalkylpiperidine ring structure and has an alkoxy group coupled to a nitrogen atom in the structure, and a benzotriazole-based compound (C), and contains, with respect to 100 pts.mass of the EVOH (A), 0.2-5 pts.mass of the hindered amine-based compound (B) and 0.1-5 pts.mass of the benzotriazole-based compound (C).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition containing an ethylene-vinyl alcohol copolymer, a laminate, an industrial film, a pipe, a method for producing the resin composition, and a masterbatch used in the production method. [Background technology]

[0002] Generally, ethylene-vinyl alcohol copolymers (hereinafter sometimes abbreviated as "EVOH") have excellent transparency, gas barrier properties, aroma retention, solvent resistance, and oil resistance. Taking advantage of these properties, they are molded into films, sheets, or containers such as bottles for food packaging materials, pharmaceutical packaging materials, industrial chemical packaging materials, and agricultural chemical packaging materials. Furthermore, their barrier properties, heat retention, and stain resistance make them widely used in industrial films and pipes. However, in these industrial film and pipe applications, they are often exposed to ultraviolet light (sunlight) and chemicals such as agricultural chemicals for long periods, raising concerns about the deterioration of EVOH's physical properties (mechanical strength, gas barrier properties, anti-fogging properties, etc.) due to light and chemicals. To suppress such deterioration of physical properties, for example, Patent Document 1 describes the blending of EVOH with hindered amine compounds and hindered phenol compounds having a specific structure. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2018 / 052014 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In recent years, there has been a demand for EVOH resin compositions with higher weather resistance. However, even when using resin compositions that incorporate hindered amine compounds and hindered phenol compounds with specific structures in EVOH, as in the conventional technology described above, the weather resistance was sometimes insufficient. In particular, when used outdoors for extended periods, it is important that mechanical properties such as impact strength are maintained after prolonged outdoor use. However, the conventional technology described above sometimes failed to adequately maintain impact strength after prolonged outdoor use. Furthermore, when many additives are used to improve weather resistance in order to maintain impact strength, film discoloration becomes a problem, and it has been found that it is difficult to achieve both the maintenance of impact strength and the suppression of film discoloration. Moreover, when film rolls are stored outdoors, for example, maintaining a low light transmittance of ultraviolet light (e.g., 300 nm) can more efficiently suppress the deterioration of the film inside the roll. However, it has been found that the conventional technology described above resulted in an increase in ultraviolet light transmittance after prolonged outdoor use.

[0005] The present invention has been made to solve the above problems, and aims to provide a resin composition, laminate, industrial film, pipe, and a method for producing the resin composition and a masterbatch used in the production method, which contain EVOH and have weather resistance that can maintain impact strength and light transmittance even after long-term outdoor use, and which can suppress discoloration of the resulting film. [Means for solving the problem]

[0006] According to the present invention, the above objective [1] A resin composition containing an ethylene-vinyl alcohol copolymer (A) (sometimes abbreviated as "EVOH(A)") having an ethylene unit content of 20 to 60 mol%, a hindered amine compound (B) (sometimes simply abbreviated as "hindered amine compound (B)") having a 2,2,6,6-tetraalkylpiperidine ring structure and an alkoxy group bonded to the nitrogen atom in the structure, and a benzotriazole compound (C), wherein the composition contains 0.2 to 5 parts by mass of the hindered amine compound (B) and 0.1 to 5 parts by mass of the benzotriazole compound (C) per 100 parts by mass of the EVOH(A); [2] The resin composition of [1], wherein the mass ratio (C) / (B) of the benzotriazole compound (C) to the hindered amine compound (B) is 0.2 to 3.5; [3] The resin composition of [1] or [2], wherein the molecular weight of the hindered amine compound (B) is 1000 or more; [4] A resin composition of any of [1] to [3] wherein the benzotriazole compound (C) has an aromatic ring to which a hydroxyl group is bonded, and the aromatic ring has a structure in which it is bonded to a nitrogen atom constituting the benzotriazole ring; [5] The resin composition of [4] wherein the aromatic ring to which the hydroxyl group is bonded has two or more substituents other than the benzotriazole ring and the hydroxyl group; [6] A resin composition of any of [1] to [5] having a halogen group on the benzotriazole ring of the benzotriazole compound (C); [7] A resin composition of any of [1] to [6] further comprising 5 ppm to 200 ppm of phosphate ions and 10 ppm to 400 ppm of alkali metal ions; [8] A resin composition containing a boron compound in an amount of 50 to 400 ppm in terms of elemental boron, any of [1] to [7]; A 100 μm thick film made from any of the resin compositions [9][1] to [8], wherein the light transmittance at a wavelength of 300 nm, as measured in accordance with JIS K 7361-1:1997, is 50% or less; For a 100 μm thick film made of any of the resin compositions

[11] [1] to [9], the light transmittance at a wavelength of 300 nm, measured in accordance with JIS K 7361-1:1997, was measured at 63°C, 50% RH, and with an irradiation intensity of 1000 W / m². 2 A resin composition from any of [1] to [9] in which the difference in light transmittance before and after a weather resistance test involving 50 hours of light irradiation (transmittance after weather resistance test (%)) - (transmittance before weather resistance test (%)) is 4.0% or less; A laminate comprising a layer made of any of the resin compositions

[11] [1] to [8]; Industrial films containing any of the laminates described in

[12] [9]~

[11] ; A pipe containing any of the laminates

[13] [9]~

[11] ; A masterbatch for producing a resin composition according to any one of items

[14] [1] to [8], comprising EVOH(A), a hindered amine compound (B), and a benzotriazole compound (C), wherein the masterbatch contains 2 to 20 parts by mass of EVOH(B) and 1 to 15 parts by mass of the benzotriazole compound (C) per 100 parts by mass of EVOH(A);

[15] A method for producing a resin composition, comprising the steps of: pre-melt-kneading 100 parts by mass of EVOH(A), 2 to 20 parts by mass of a hindered amine compound (B), and 1 to 15 parts by mass of a benzotriazole compound (C) to obtain a masterbatch; and melt-kneading the obtained masterbatch with EVOH(A) to obtain a resin composition containing 0.2 to 5 parts by mass of the hindered amine compound (B) and 0.1 to 5 parts by mass of the benzotriazole compound (C) per 100 parts by mass of EVOH(A); This is achieved by providing [the necessary services / services]. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a resin composition, laminate, industrial film, pipe, and a method for producing the resin composition and a masterbatch used in the production method, all of which have weather resistance that allows them to maintain impact strength and light transmittance even after long-term outdoor use, and which can suppress discoloration of the resulting film, and which have EVOH. [Modes for carrying out the invention]

[0008] The resin composition of the present invention is a resin composition containing EVOH (A), a hindered amine compound (B), and a benzotriazole compound (C), wherein the composition contains 0.2 to 5 parts by mass of the hindered amine compound (B) and 0.1 to 5 parts by mass of the benzotriazole compound (C) per 100 parts by mass of EVOH (A). When the resin composition of the present invention contains the hindered amine compound (B), it tends to suppress deterioration of the film's hue after long-term outdoor use, while it tends to increase the light transmittance at 300 nm after long-term outdoor use. Furthermore, when it contains the benzotriazole compound (C), it can reduce the light transmittance at 300 nm and suppress the increase in light transmittance at 300 nm after long-term outdoor use, while it tends to worsen the film's hue after long-term outdoor use. Furthermore, by including specific amounts of hindered amine compound (B) and benzotriazole compound (C) in the resin composition of the present invention, it is surprisingly possible to significantly suppress the increase in light transmittance at 300 nm after prolonged outdoor use without degrading the hue of the film after prolonged outdoor use, and furthermore, to suppress the decrease in impact strength after prolonged outdoor use. The reason why the decrease in impact strength can be suppressed is not clear, but when specific amounts of hindered amine compound (B) and benzotriazole compound (C) are included, the decrease in molecular weight of EVOH(A) after weathering tests is significantly suppressed, while when only one of hindered amine compound (B) or benzotriazole compound (C) is included, the decrease in molecular weight is not suppressed to a great extent. Therefore, it is presumed that the synergistic effect of hindered amine compound (B) and benzotriazole compound (C) suppresses the decrease in molecular weight and thus suppresses the decrease in impact strength. In addition, the resin composition of the present invention can also suppress the decrease in barrier properties after prolonged outdoor use, so even if it is used for the purpose of suppressing the migration of pesticides, for example, its function can be maintained for a long period of time. Barrier properties can be indirectly evaluated by oxygen permeability measured in accordance with JIS K 7126:2006 (isobaric method).

[0009] In this specification, since weather resistance tests are conducted to evaluate the physical properties after long-term outdoor use, "after long-term outdoor use" may be expressed as "after weather resistance testing." Also, "light transmittance at 300 nm" may be expressed as "light transmittance (300 nm)." Furthermore, the property of suppressing the increase in light transmittance (300 nm) and the decrease in impact strength after weather resistance testing may be expressed as weather resistance.

[0010] [EVOH(A)] The resin composition of the present invention contains EVOH(A) having an ethylene unit content of 20 to 60 mol%. EVOH(A) is a copolymer having ethylene units and vinyl alcohol units, and can be obtained, for example, by saponifying a copolymer containing ethylene and a vinyl ester using an alkaline catalyst or the like. Typical vinyl esters include vinyl acetate, but other fatty acid vinyl esters (such as vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, and vinyl versatate) can also be used.

[0011] The lower limit of the ethylene unit content of EVOH(A) is 20 mol%, preferably 23 mol%, more preferably 25 mol%, and even more preferably 27 mol%. The upper limit of the ethylene unit content of EVOH(A) is 60 mol%, preferably 55 mol%, and more preferably 50 mol%. If the ethylene unit content is below the lower limit, the melt moldability of the resin composition may decrease. Conversely, if the ethylene unit content exceeds the upper limit, the gas barrier properties of the resulting industrial and agricultural films, pipes, etc., may decrease. The ethylene unit content of EVOH(A) is, 1 It can be determined by 1H-NMR measurement.

[0012] The lower limit of the degree of saponification of EVOH(A) is preferably 90 mol%, more preferably 95 mol%, and even more preferably 99 mol%. When the degree of saponification of EVOH(A) is above the lower limit, the gas barrier properties of the resulting laminate are improved. The degree of saponification refers to the ratio of vinyl alcohol units to the total number of vinyl alcohol units and vinyl ester units in EVOH(A). The upper limit of the degree of saponification may be 99.99 mol%. The degree of saponification of EVOH(A) is, 1 It can be determined by 1H-NMR measurement.

[0013] EVOH(A) may contain other monomer units other than ethylene, vinyl esters, and vinyl alcohols, as long as they do not hinder the effects of the present invention. In particular, by introducing a modified group containing a primary hydroxyl group having a specific structure, it may be possible to achieve a high level of both gas barrier properties and moldability of EVOH(A). The content of other monomer units is preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 1 mol% or less, and particularly preferably substantially absent. Examples of such other monomers include alkenes such as propylene, butylene, pentene, and hexene; 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, 3,4-diasiloxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-1-butene, 3,4-diasiloxy-1-butene, and 3-acyloxy-4-methyl -1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diasiloxy-2-methyl-1-butene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diasiloxy-1-pentene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy-1-hexene, 5,6-diasiloxy Examples include ester group-containing alkenes such as xy-1-hexene and 1,3-diacetoxy-2-methylenepropane or their saponifies; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, and itaconic acid or their anhydrides, salts, or mono- or dialkyl esters; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; olefin sulfonic acids such as vinyl sulfonic acid, allyl sulfonic acid, and methallyl sulfonic acid or their salts; vinylsilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxy-ethoxy)silane, and γ-methacryloxypropylmethoxysilane; alkyl vinyl ethers, vinyl ketones, N-vinylpyrrolidone, vinyl chloride, and vinylidene chloride.

[0014] EVOH (A) may be modified by urethanization, acetalization, cyanoethylation, oxyalkylation, etc. as necessary. Oxyalkylation can be carried out using an epoxy compound. For example, epoxyethane (ethylene oxide), epoxypropane, 1,2-epoxybutane, 2,3-epoxybutane, 3-methyl-1,2-epoxybutane, 1,2-epoxypentane, 3-methyl-1,2-epoxypentane, 1,2-epoxyhexane, 2,3-epoxyhexane, 3,4-epoxyhexane, 3-methyl-1,2-epoxyhexane, 3-methyl-1,2-epoxyheptane, 4-methyl-1,2-epoxyheptane, 1,2-epoxyoctane, 2,3-epoxyoctane, 1,2-epoxynonane, 2,3-epoxynonane, 1,2-epoxydecane, 1,2-epoxydodecane, epoxyethylbenzene, 1-phenyl-1,2-propane, 3-phenyl-1,2-epoxypropane, various alkyl glycidyl ethers, various alkylene glycol monoglycidyl ethers, various alkenyl glycidyl ethers, various epoxyalkanols such as glycidol, various epoxycycloalkanes, various epoxycycloalkenes, etc. Among them, 1,2-epoxybutane, 2,3-epoxybutane, epoxypropane, epoxyethane or glycidol is preferable, and epoxypropane or glycidol is more preferable.

[0015] The melt flow rate (MFR) (at 190 °C under a load of 2160 g) of EVOH (A) is preferably 0.1 to 30 g / 10 min, more preferably 0.3 g to 25 g / 10 min, and even more preferably 0.5 g to 20 g / 10 min. However, for those with a melting point near 190 °C or exceeding 190 °C, it is measured at a plurality of temperatures above the melting point under a load of 2160 g, plotted with the reciprocal of the absolute temperature on the horizontal axis and the logarithm of MFR on the vertical axis in a semi-logarithmic graph, and represented by the value extrapolated to 190 °C.

[0016] EVOH (A) can be used alone or in combination of two or more.

[0017] [Hindered amine compound (B)] The resin composition of the present invention contains 0.2 to 5 parts by mass of hindered amine compound (B) per 100 parts by mass of EVOH (A). The inclusion of hindered amine compound (B) in the resin composition of the present invention tends to suppress color deterioration after weather resistance testing, and when used in combination with benzotriazole compound (C) described later, the weather resistance is significantly improved. Hindered amine compound (B) has a 2,2,6,6-tetraalkylpiperidine ring structure and has an alkoxy group bonded to the nitrogen atom in the structure. As the hindered amine compound (B), commercially available products can be used, for example, TINUVIN NOR 371 (manufactured by BASF Japan Ltd., general formula (IV) below, molecular weight: 2800-4000), Hostavin NOW (manufactured by Clariant, chemical formula: general formula (I) below, molecular weight: approximately 2000), FLAMESTAB NOR 116 (manufactured by BASF Japan Ltd., chemical formula: general formula (II) below, molecular weight: 2261), Chimassorb 2020 (manufactured by BASF Japan Ltd., 1,6-Hexanediamine, N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-polymer with 2,4,6-trichloro-1,3,5-triazine, reaction products with N-butyl-1-butanamine and Examples include N-butyl-2,2,6,6-tetramethyl-4-piperidinamine (molecular weight: 2600-3400), with TINUVIN NOR 371 being particularly preferred. These hindered amine compounds (B) may be used alone or in combination of two or more.

[0018] [ka]

[0019] (In the above general formula (I), R1 is an alkyl group having 1 to 24 carbon atoms or an alkenyl group having 2 to 24 carbon atoms.)

[0020] [ka]

[0021] (In the above general formula (II), R2 is the substituent shown in the following general formula (III), and the binding site is on the triazine ring.)

[0022] [ka]

[0023] [ka]

[0024] (In the above general formula (IV), R3 to R7 are arbitrary substituents, and they may be different substituents, the same substituent, or only some of the substituents may be the same.)

[0025] The molecular weight of the hindered amine compound (B) is preferably 1000 or more. A molecular weight of 1000 or more suppresses the bleed-out and volatilization of the hindered amine compound (B) after long-term outdoor use, and tends to maintain weather resistance over a long period. Furthermore, when the resin composition of the present invention is melt-molded into a molded product such as a film, if the hindered amine compound (B) bleeds out, it may adhere to the mold of the molding machine, causing defects in the appearance of the molded product surface. Therefore, from the viewpoint of suppressing defects in appearance, it is preferable that the molecular weight of the hindered amine compound (B) is 1000 or more. The molecular weight of the hindered amine compound (B) is more preferably 1400 or more, even more preferably 1700 or more, and particularly preferably 1900 or more. The molecular weight of the hindered amine compound (B) may be 5000 or less.

[0026] The content of hindered amine compound (B) in the resin composition of the present invention is 0.2 to 5 parts by mass per 100 parts by mass of EVOH(A). The content of hindered amine compound (B) is preferably 0.25 parts by mass or more, and more preferably 0.3 parts by mass or more. If the content of hindered amine compound (B) is less than 0.2 parts by mass, sufficient weather resistance cannot be obtained. On the other hand, if the content of hindered amine compound (B) is more than 5 parts by mass, significant discoloration occurs in the film after the weather resistance test. Also, if the content is more than 5 parts by mass, the viscosity of the resin may decrease, making stable production impossible. The content of hindered amine compound (B) is preferably 4 parts by mass or less, more preferably 2.5 parts by mass or less, and even more preferably 2 parts by mass or less.

[0027] [Benzotriazole compounds (C)] The resin composition of the present invention contains 0.1 to 5 parts by mass of a benzotriazole compound (C) per 100 parts by mass of EVOH (A). The resin composition of the present invention tends to suppress the increase in light transmittance (300 nm) after weather resistance testing by containing the benzotriazole compound (C), and when used in combination with a hindered amine compound (B), the weather resistance is significantly improved. The benzotriazole compound is not particularly limited as long as it has a benzotriazole skeleton, and known compounds can be used. From the viewpoint of further improving weather resistance, it is preferable that the benzotriazole compound (C) has an aromatic ring to which a hydroxyl group is bonded, and that such aromatic ring has a structure in which it is bonded to a nitrogen atom constituting the benzotriazole ring. Furthermore, it is more preferable that the aromatic ring to which the hydroxyl group is bonded is bonded to the nitrogen at position 2 of the benzotriazole ring. Furthermore, it is preferable that the aromatic ring to which the hydroxyl group is bonded has two or more substituents other than the hydroxyl group and the benzotriazole ring. In addition, it is preferable that the benzotriazole compound (C) has a halogen group on the benzotriazole ring.

[0028] As the benzotriazole compound (C), commercially available products can be used, for example, ADEKA Stab® LA-36 (manufactured by ADEKA Corporation, chemical formula: 2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol), molecular weight: 315), Tinuvin® 329 (manufactured by BASF Japan Ltd., chemical formula: 2Phenol,2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl), molecular weight: 323), Tinuvin® 234 (manufactured by BASF Japan Ltd., chemical formula: Phenol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl), molecular weight: 448), Tinuvin® Examples include P (manufactured by BASF Japan Ltd., chemical formula: Phenol,2-(2H-benzotriazol-2-yl)-4-methyl, molecular weight: 225) and Tinuvin® 360 (manufactured by BASF Japan Ltd., chemical formula: Phenol,2,2'-methylene-bis(6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)), molecular weight: 659), with Adekastab® LA-36 being particularly preferred.

[0029] The content of benzotriazole compound (C) in the resin composition of the present invention is 0.1 to 5 parts by mass per 100 parts by mass of EVOH(A). The content of benzotriazole compound (C) is preferably 0.2 parts by mass or more, and more preferably 0.25 parts by mass or more. If the content of benzotriazole compound (C) is less than 0.1 parts by mass, the impact strength decreases due to an increase in light transmittance and a decrease in molecular weight retention after the weathering test. On the other hand, if the content of benzotriazole compound (C) is more than 5 parts by mass, significant discoloration occurs in the film after the weathering test. The content of benzotriazole compound (C) is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, and even more preferably 1 part by mass or less.

[0030] Benzotriazole compounds (C) may be used alone or in combination of two or more.

[0031] [Resin composition] In the resin composition of the present invention, the mass ratio (C) / (B) of the benzotriazole compound (C) to the hindered amine compound (B) is preferably 0.2 to 3.5. When the mass ratio (C) / (B) is 0.2 or higher, the discoloration of the film after the weathering test tends to be further suppressed. A mass ratio (C) / (B) of 0.3 or higher is more preferable, and 0.4 or higher is even more preferable. Furthermore, when the mass ratio (C) / (B) is 3.5 or lower, the discoloration of the film tends to be further suppressed. A mass ratio (C) / (B) of 3.0 or lower is more preferable, 2.0 or lower is even more preferable, 1.5 or lower is even more preferable, and 1.0 or lower is particularly preferable.

[0032] The resin composition of the present invention may contain other optional components besides EVOH(A), hindered amine compounds (B), and benzotriazole compounds (C), such as boron compounds, carboxylic acids, phosphorus compounds, metal ions, antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, heat stabilizers, and other resins other than EVOH(A). The resin composition of the present invention may contain two or more of these components. When the resin composition of the present invention contains other optional components, the upper limit of their total content is preferably 1% by mass, and may also be preferably 0.5% by mass.

[0033] The resin composition of the present invention preferably contains a boron compound as another component. This helps to suppress torque fluctuations during heating and melting. The boron compound is not particularly limited and includes boric acids, boric acid esters, borate salts, boron hydride compounds, etc. Specifically, examples of boric acids include orthoboric acid, metaboric acid, tetraboric acid, etc. Examples of boric acid esters include triethyl borate, trimethyl borate, etc. Examples of borate salts include alkali metal salts of the above-mentioned boric acids, alkaline earth metal salts, borax, etc. Among these compounds, orthoboric acid (hereinafter sometimes simply referred to as boric acid) is preferred. The content of the boron compound is preferably 50 to 400 ppm or less in terms of boron element. When the content of the boron compound is 50 ppm or more, the melt moldability tends to stabilize, more preferably 70 ppm or more, and even more preferably 100 ppm or more. On the other hand, when the boron compound content is 400 ppm or less, the deterioration of moldability tends to be suppressed, more preferably 350 ppm or less, and may also be 300 ppm or less.

[0034] Carboxylic acids prevent discoloration of the resin composition and, consequently, the molded article, and also suppress gelation during melt molding. Examples of carboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, lactic acid, and their salts. Preferred carboxylic acids are those with four or fewer carbon atoms or saturated carboxylic acids, with acetic acid being more preferred. These acetic acids include acetic acid and acetate salts. It is preferable to use acetic acid and acetate salts in combination, and more preferable to use acetic acid and sodium acetate in combination. When the resin composition of the present invention contains carboxylic acids, the lower limit of the carboxylic acid content is preferably 50 ppm, more preferably 80 ppm, and even more preferably 120 ppm. The upper limit of the carboxylic acid content is preferably 1,000 ppm, more preferably 500 ppm, and even more preferably 400 ppm. By setting the carboxylic acid content above the above lower limit, a sufficient discoloration suppression effect can be obtained, and the occurrence of yellowing can be sufficiently suppressed. On the other hand, by keeping the carboxylic acid content below the above upper limit, gelation is less likely to occur during melt molding, especially during long melt molding periods, resulting in a better appearance for molded products.

[0035] Phosphorus compounds suppress the occurrence of defects such as streaks and fish eyes, as well as discoloration, and improve long-run performance. Examples of phosphorus compounds include phosphates such as phosphoric acid and phosphorous acid. The above phosphates may be in the form of monophosphate, diphosphate, or tertiary phosphate. The cation species of the phosphate is not particularly limited, but alkali metal salts and alkaline earth metal salts are preferred, and among these, compounds containing phosphate ions such as sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, and dipotassium hydrogen phosphate are more preferred, with sodium dihydrogen phosphate and dipotassium hydrogen phosphate being even more preferred. When the resin composition of the present invention contains a compound containing phosphate ions as a phosphorus compound, the lower limit of the phosphate ion content is preferably 5 ppm, more preferably 10 ppm, even more preferably 20 ppm, and particularly preferably 30 ppm. The upper limit of the phosphorus compound content relative to EVOH(A) is preferably 200 ppm, more preferably 150 ppm, and even more preferably 100 ppm. By setting the phosphorus compound content above the lower limit or below the upper limit, thermal stability is improved, and the formation of gel-like particles and discoloration during long-term melt molding becomes less likely.

[0036] Examples of metal ions include monovalent metal ions, divalent metal ions, and other transition metal ions, which may consist of one or more types. Among these, monovalent metal ions and divalent metal ions are preferred. Among monovalent metal ions, alkali metal ions are preferred, such as lithium, sodium, potassium, rubidium, and cesium ions, with sodium or potassium ions being preferred from the viewpoint of industrial availability. Examples of alkali metal salts that provide alkali metal ions include aliphatic carboxylates, aromatic carboxylates, carbonates, hydrochlorides, nitrates, sulfates, phosphates, and metal complexes. Among these, aliphatic carboxylates and phosphates are preferred from the viewpoint of availability, and specifically, sodium acetate, potassium acetate, sodium phosphate, and potassium phosphate are preferred. It is also preferable to include divalent metal ions as metal ions. When the metal ions include divalent metal ions, for example, the thermal degradation of EVOH when trim is recovered and reused may be suppressed, and the generation of gel and blemishes in the resulting molded article may be suppressed. Examples of divalent metal ions include beryllium, magnesium, calcium, strontium, barium, and zinc ions, but magnesium, calcium, or zinc ions are preferred from the viewpoint of industrial availability. Examples of divalent metal salts that provide divalent metal ions include carboxylates, carbonates, hydrochlorides, nitrates, sulfates, phosphates, and metal complexes, with carboxylates being preferred. Preferred carboxylic acids constituting the carboxylates are carboxylic acids having 1 to 30 carbon atoms, specifically including acetic acid, propionic acid, butyric acid, stearic acid, lauric acid, montanic acid, behenic acid, octicic acid, sebacic acid, ricinoleic acid, myristic acid, palmitic acid, etc., with acetic acid and stearic acid being preferred among them. When the resin composition of the present invention contains alkali metal ions, the lower limit of the alkali metal ion content is preferably 10 ppm, more preferably 100 ppm, and even more preferably 150 ppm. On the other hand, the upper limit of the alkali metal ion content is preferably 400 ppm, and more preferably 350 ppm. When the alkali metal ion content is above the lower limit mentioned above, the resulting multilayer structure tends to have good interlayer adhesion.On the other hand, if the metal ion content is below the above upper limit, the stain resistance tends to be good.

[0037] Examples of antioxidants include 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4'-thiobis(6-t-butylphenol), 2,2'-methylene-bis(4-methyl-6-t-butylphenol), and octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate. Examples of ultraviolet absorbers include ethylene-2-cyano-3,3'-diphenyl acrylate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, and 2-hydroxy-4-oxybenzophenone.

[0038] Examples of plasticizers include dimethyl phthalate, diethyl phthalate, dioctyl phthalate, waxes, liquid paraffin, and phosphate esters. Examples of antistatic agents include pentaerythritol monostearate, sorbitan monopalmitate, sulfated polyolefins, polyethylene oxide, and polyethylene glycol (trade name: Carbowax).

[0039] Examples of lubricants include ethylene bisstearamide and butyl stearate. Examples of colorants include carbon black, phthalocyanine, quinacridone, indoline, azo pigments, and red iron oxide. Examples of fillers include glass fiber, wollastonite, calcium silicate, talc, and montmorillonite. Examples of heat stabilizers include hindered phenol compounds and hindered amine compounds.

[0040] Other resins besides EVOH(A) include, for example, polyamides and polyolefins.

[0041] In the resin composition of the present invention, the proportion of EVOH(A), hindered amine compound(B), and benzotriazole compound(C) is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and particularly preferably 99% by mass or more. The resin composition of the present invention may consist substantially only of EVOH(A), hindered amine compound(B), and benzotriazole compound(C), or it may consist only of EVOH(A), hindered amine compound(B), and benzotriazole compound(C). In this specification, "substantially consisting only of" means that the inclusion of optional components is permitted as long as it does not affect the effects of the present invention, and in this specification, "consisting only of" means that optional components other than impurities that are inevitably included are excluded.

[0042] The resin composition of the present invention is used to create a 100 μm thick film made from the resin composition of the present invention, which is then subjected to irradiation at 63°C, 50% RH, and an irradiation intensity of 1000 W / m². 2 It is preferable that the retention rate of the weight-average molecular weight (Mw) after a weathering test involving 50 hours of light irradiation is 90% or higher. Here, the retention rate of the weight-average molecular weight (Mw) refers to the retention rate (%) calculated by dividing the Mw after the weathering test by the Mw before the weathering test (Mw after weathering test / Mw before weathering test × 100). A retention rate of 93% or higher is more preferable, and 95% or higher is even more preferable. Furthermore, the retention rate of the weight-average molecular weight (Mw) after the weathering test may be 99.9% or lower. When the retention rate of Mw is within the above range, the impact strength after the weathering test tends to be good. The weathering test and the retention rate of Mw can be measured by the method described in the examples.

[0043] The resin composition of the present invention is used to create a 100 μm thick film made from the resin composition of the present invention, which is then subjected to irradiation at 63°C, 50% RH, and an irradiation intensity of 1000 W / m². 2It is preferable that the retention rate of the number-average molecular weight (Mn) after a weathering test involving 50 hours of light irradiation is 80% or higher. Here, the retention rate of the number-average molecular weight (Mn) refers to the retention rate (%) calculated by dividing the Mn after the weathering test by the Mn before the weathering test (Mn after weathering test / Mn before weathering test × 100). A retention rate of 85% or higher is more preferable, and 87% or higher is even more preferable. Furthermore, the retention rate of the number-average molecular weight (Mn) after the weathering test may be 99.9% or lower. When the retention rate of Mn is within the above range, the impact strength after the weathering test tends to be good. The weathering test and the retention rate of Mn can be measured by the method described in the examples.

[0044] When the molecular weight retention rates of Mw and Mn are within the above range, the mechanical properties of the laminate, such as impact strength, are maintained at a high level.

[0045] The resin composition of the present invention is preferably such that a light transmittance (300 nm) of 50% or less, measured in accordance with JIS K 7361-1:1997 for a 100 μm thick film made from the resin composition of the present invention, is good from the viewpoint of good weather resistance of the entire roll when the laminate roll is stored outdoors. A light transmittance (300 nm) of 30% or less is more preferable, 10% or less is even more preferable, and 5% or less is particularly preferable. Also, under 63°C, 50% RH, and an irradiation intensity of 1000 W / m² 2 The light transmittance (300nm) after a weather resistance test involving 50 hours of light irradiation is preferably 50% or less, more preferably 30% or less, even more preferably 10% or less, and particularly preferably 8% or less. (63°C, 50%RH, irradiation intensity 1000W / m²) 2 The difference in light transmittance before and after a weather resistance test involving 50 hours of light irradiation (transmittance after weather resistance test (%)) - (transmittance before weather resistance test (%)) is preferably 4.0% or less, more preferably 3.0% or less, even more preferably 2.3% or less, and particularly preferably 2.0% or less.

[0046] The resin composition of the present invention preferably has an impact strength of 17.5 kgf·cm or more, more preferably 19.0 kgf·cm or more, and even more preferably 19.8 kgf·cm or more, for a film made from the resin composition of the present invention with a thickness of 100 μm. The impact strength may also be 25.0 kgf·cm or less. Furthermore, under conditions of 63°C, 50% RH, and an irradiation intensity of 1000 W / m², the impact strength is 25.0 kgf·cm or less. 2 The impact strength after a weather resistance test involving 50 hours of light irradiation is preferably 17.5 kgf·cm or higher, more preferably 18.0 kgf·cm or higher, even more preferably 18.5 kgf·cm or higher, and particularly preferably 19.5 kgf·cm or higher. The impact strength can be measured by the method described in the examples.

[0047] The method for producing the resin composition of the present invention is not particularly limited, but for example, it can be produced by mixing and melt-kneading EVOH(A), a hindered amine compound (B), a benzotriazole compound (C), and various additives such as the above-mentioned other components as needed. Specifically, it can be carried out using known mixing or kneading equipment such as a kneader-ruder, extruder, mixing roll, or Banbury mixer. The temperature during melt-kneading is usually 110 to 300°C. The above-mentioned various additives may be pre-contained in EVOH(A). The method for pre-containing the additives in EVOH(A) is not particularly limited, and for example, the various additives can be pre-contained in EVOH(A) by immersing EVOH(A) pellets in a solution containing the various additives and drying them.

[0048] Furthermore, the resin composition of the present invention can also be manufactured by a manufacturing method that includes a step through a masterbatch. A preferred manufacturing method that includes a step through a masterbatch is one in which 100 parts by mass of EVOH(A), 2 to 20 parts by mass of a hindered amine compound (B), and 1 to 15 parts by mass of a benzotriazole compound (C) are pre-melted and kneaded to obtain a masterbatch, and then the obtained masterbatch is melt-kneaded with EVOH(A). By including a step of pre-preparing a masterbatch, the hindered amine compound (B) and the benzotriazole compound (C) are better dispersed in EVOH(A) than in other mixing methods, and the weather resistance tends to be superior. Note that the EVOH(A) contained in the masterbatch and the EVOH(A) used when further melt-kneading with the masterbatch may be the same or different. The manufacturing method of the resin composition of the present invention is preferably one that includes a step through a masterbatch from the viewpoint of further improving the weather resistance of the obtained resin composition.

[0049] [Masterbatch] A masterbatch used in a method for producing a resin composition that includes the above-described steps is also an embodiment of the present invention. The masterbatch of the present invention contains EVOH(A), a hindered amine compound (B), and a benzotriazole compound (C) in high concentrations, and is used in the production of the resin composition of the present invention after being diluted to a specified ratio with EVOH(A). The masterbatch of the present invention contains EVOH(A), a hindered amine compound (B), and a benzotriazole compound (C), with 2 to 20 parts by mass of the hindered amine compound (B) and 1 to 15 parts by mass of the benzotriazole compound (C) per 100 parts by mass of EVOH(A). When the content of the hindered amine compound (B) and the benzotriazole compound (C) is within the above-described range, the masterbatch can be produced stably.

[0050] The method for incorporating the hindered amine compound (B) and the benzotriazole compound (C) into the masterbatch of the present invention is not particularly limited. Examples include a method of dry blending EVOH(A), the hindered amine compound (B), and the benzotriazole compound (C) and then melt-kneading them in an extruder; a method of immersing EVOH(A) in a solution in which the hindered amine compound (B) and the benzotriazole compound (C) are dissolved; a method of melting EVOH(A) and mixing it with the hindered amine compound (B) and the benzotriazole compound (C); and a method of melt-blending EVOH(A), the hindered amine compound (B), and the benzotriazole compound (C) in an extruder. Among these, the method of dry blending EVOH(A), the hindered amine compound (B), and the benzotriazole compound (C) and then melt-kneading them in an extruder is preferred.

[0051] [Laminated structure] The laminate of the present invention has at least one layer made of the resin composition of the present invention and layers made of other components. The laminate has advantages such as improved functionality compared to a single-layer molded article. The lower limit of the number of layers in the laminate may be two or three. The upper limit of the number of layers in the laminate may be 1000, 100, or 10. Furthermore, the laminate of the present invention may further have layers formed from components other than resin, such as layers formed from paper, metal layers, etc.

[0052] Other layers include thermoplastic resin layers formed from thermoplastic resins and adhesive resin layers formed from adhesive resins. The layer structure of the laminate of the present invention is not particularly limited, and when E represents a layer made from the resin composition of the present invention, Ad represents a layer obtained from an adhesive resin, T represents a layer obtained from a thermoplastic resin, and " / " indicates direct lamination, examples of structures include T / E / T, E / Ad / T, T / Ad / E / Ad / T, E / Ad / T / Ad / E, E / Ad / T / Ad / E / Ad / T / Ad / E, and so on. Each of these layers may be a single layer or a multilayer. In addition, other layers not mentioned above may be present as long as they do not hinder the effects of the present invention. An example of other layers is a recovery layer. In particular, a recovery composition containing the recovered material of the laminate of the present invention may be reused as part or all of the recovery layer.

[0053] Examples of thermoplastic resins include linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, polypropylene, propylene-α-olefin (α-olefin with 4 to 20 carbon atoms) copolymer, polybutene, polypentene, and other olefins alone or copolymers thereof; polyesters such as polyethylene terephthalate; polyester elastomers; polyamides such as nylon-6 and nylon-66; polystyrene; polyvinyl chloride, polyvinylidene chloride, acrylic resins, vinyl ester resins, polyurethane elastomers, polycarbonate, chlorinated polyethylene, and chlorinated polypropylene. Among these, polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyamide, polystyrene, and polyester are preferably used, polypropylene and polyethylene are more preferably used, and polyethylene is even more preferably used.

[0054] The adhesive resin is not particularly limited as long as it has adhesion to the gas barrier layer and the layer made of other components, but an adhesive resin containing a carboxylic acid-modified polyolefin is preferred. As the carboxylic acid-modified polyolefin, a modified olefin polymer containing a carboxyl group obtained by chemically bonding an ethylenically unsaturated carboxylic acid, its ester, or its anhydride to an olefin polymer is preferred, and a maleic anhydride-modified olefin polymer is more preferred. Here, olefin polymers refer to polyolefins such as polyethylene, linear low-density polyethylene, polypropylene, and polybutene, and copolymers of olefins and other monomers. Among these, linear low-density polyethylene, ethylene-vinyl acetate copolymer and ethylene-ethyl acrylate copolymer are preferred, and linear low-density polyethylene and ethylene-vinyl acetate copolymer are particularly preferred.

[0055] The method for producing the laminate of the present invention is not particularly limited, and examples include a method of melt-extruding other components onto a molded article (film, sheet, etc.) made of the resin composition of the present invention, a method of co-extruding the resin composition of the present invention and other components, a method of co-injection molding the resin composition of the present invention and other components, and a method of laminating a barrier layer made of the resin composition of the present invention and a layer made of other components using a known adhesive such as an organotitanium compound, an isocyanate compound, or a polyester compound.

[0056] The method for co-extruding the resin composition of the present invention with other components is not particularly limited and can include the multi-manifold confluence T-die method, the feedblock confluence T-die method, the inflation method, and the like.

[0057] [Application] The resin composition of the present invention has excellent weather resistance and manufacturing stability, making it suitable for use as industrial films and pipes having a gas barrier layer made of such a resin composition. More specifically, it is suitable for agricultural films such as soil fumigation films, silage films, and greenhouse films; grain storage bags; geomembranes; hot water circulation pipes, fuel pipes, etc. The present invention also provides agricultural films (preferably soil fumigation films, silage films, or greenhouse films), grain storage bags, geomembranes, and pipes (preferably hot water circulation pipes or fuel pipes) having a gas barrier layer made of such a resin composition of the present invention.

[0058] The resin composition of the present invention is particularly useful when used as a soil fumigation film to prevent the evaporation of chloropicrin, methyl bromide, and other substances used as soil fumigants, and as a silage film to wrap silage that becomes acidic due to fermentation. Under these conditions, the resin composition of the present invention is exposed to acidic conditions by the chemicals or silage. When used outdoors for a long period of time under acidic conditions, the deterioration of the film is further accelerated, but even under such conditions, the soil fumigation film and silage film made from the resin composition of the present invention have very good weather resistance. [Examples]

[0059] The present invention will be further explained by the following examples, but the present invention is not limited thereto. The measurement, calculation, and evaluation methods were as follows.

[0060] [Materials used] <Hindered amine compounds (B)> B-1: Tinuvin NOR 371 (manufactured by BASF Japan Ltd., molecular weight 1000 or higher) B-2: FLAMESTAB NOR 116 (manufactured by BASF Japan Ltd., molecular weight 1000 or higher) B-3: HOSTAVIN NOW (manufactured by Clariant, molecular weight 1000 or more) <Benzotriazole compounds (C)> C-1: ADEKA Stab LA-36 (manufactured by ADEKA Corporation, 2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol) C-2: Tinuvin 329 (manufactured by BASF Japan Ltd., 2Phenol,2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)) C-3: Tinuvin 234 (manufactured by BASF Japan Ltd., Phenol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)) <Additive (C') used in the comparative example> C'-1: Irganox 1098 (manufactured by BASF Japan Ltd., N,N'-(1,6-Hexanediyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide]) C'-2: Chimassorb 81 (manufactured by BASF Japan Ltd., Methanone, 2-hydroxy-4-(octyloxy)-phenyl)

[0061] [Evaluation Method] (1) Measurement of phosphate ion, alkali metal ion, and boron element content 0.5 g of resin composition pellets obtained in the examples and comparative examples were placed in a Teflon® pressure vessel, and 5 mL of concentrated nitric acid was added to decompose it at room temperature for 30 minutes. After 30 minutes, the lid was closed, and decomposition was carried out by heating at 150°C for 10 minutes, then at 180°C for 5 minutes, using a wet decomposition apparatus (Actac Co., Ltd.: "speedwave4"), and then cooled to room temperature. This processed solution was transferred to a 50 mL volumetric flask (TPX) and diluted with pure water. The metal content of this solution was analyzed using an ICP emission spectrometer (PerkinElmer "Avio500"), and the content of phosphate ions, sodium metal ions, and boron element was measured.

[0062] (2) Quantification of acetic acid 20 g of the resin composition pellets obtained in the examples and comparative examples were put into 100 ml of ion-exchanged water and heated and extracted at 95 °C for 6 hours. Using phenolphthalein as an indicator, the extract was neutral titrated with 1 / 50 N NaOH to quantify the acetic acid content.

[0063] (3) Weather resistance test Regarding the single-layer films obtained in the examples and comparative examples, using an Eye Super UV tester "SUV-W15" manufactured by Iwasaki Electric Co., Ltd., an accelerated weather resistance test was carried out for 50 hours under the conditions of an irradiance of 1000 W / m 2 , a black panel temperature of 63 °C, and a relative humidity of 50%. Before and after the test, the following were evaluated: (4) molecular weight retention rate, (5) light transmittance, (6) impact strength, and (7) film coloring.

[0064] (4) Molecular weight retention rate The weight average molecular weight (Mw) and number average molecular weight (Mn) of the single-layer film before and after the weather resistance test were measured by gel permeation chromatography (GPC). The measurement conditions are as follows. Apparatus: Gel Permeation Chromatography "HLC-8320" manufactured by Tosoh Corporation Columns: Two "GMHHR-H(S)" manufactured by Tosoh Corporation Column temperature: 40 °C Mobile phase: Hexafluoroisopropanol + 20 mM CF3COONa, flow rate: 0.2 mL / min <s Detector: RI, sample concentration: 0.1 wt% (hexafluoroisopropanol solution) Based on the measurement results, the Mw after the weather resistance test was divided by the Mw before the weather resistance test to calculate the Mw retention rate (%) (Mw after the weather resistance test / Mw before the weather resistance test × 100). Similarly, the Mn after the weather resistance test was divided by the Mn before the weather resistance test to calculate the Mn retention rate (%) (Mn after the weather resistance test / Mn before the weather resistance test × 100).

[0065] (5) Light transmittance The light transmittance at a wavelength of 300 nm was measured for the single-layer films obtained in the examples and comparative examples using a Shimadzu UV-Vis spectrophotometer "UV-2450". In addition, the difference in light transmittance before and after the weather resistance test described in evaluation method (2) above was calculated.

[0066] (6) Impact strength The single-layer films obtained in the examples and comparative examples were conditioned for 24 hours under conditions of 23°C and 50% RH, and then their impact strength was measured using a film impact tester under the same conditions. The measurement was performed five times at different locations, and the average value was adopted as the measurement result.

[0067] (7) Coloring The single-layer films obtained in the examples and comparative examples were visually inspected, and the degree of yellowing was evaluated according to the following criteria. Of the following criteria, A, B, and C were judged to be at a usable level. A: No yellowing was observed at all. B: Slight yellowing was observed. C: Slight yellowing was observed. D: Yellowing was observed. E: Significant yellowing was observed.

[0068] Example 1 A hydrated EVOH pellet with an ethylene unit content of 38 mol% and a degree of saponification of 99.9 mol% was immersed in an aqueous solution containing acetic acid, phosphoric acid, sodium acetate, and boric acid at 25°C for 6 hours with stirring, then dehydrated, dried in a hot air dryer (DN6101, manufactured by Yamato Scientific Co., Ltd.) at 80°C for 4 hours, and then dried at 120°C for 40 hours to obtain dried EVOH pellets (EVOH-1, moisture content 0.25%, MFR (190°C, under 2160g load) 1.7g / 10 min). The concentrations of acetic acid, phosphoric acid, sodium acetate, and boric acid were appropriately adjusted so that the content in the resin composition obtained in this example was 100 ppm of acetic acid, 40 ppm of phosphate ions, 150 ppm of sodium ions, and 180 ppm of boron.

[0069] To 100 parts by mass of the obtained dried EVOH pellets, 0.4 parts by mass of Tinuvin NOR 371 (B-1) (manufactured by BASF Japan Ltd.) and 0.3 parts by mass of Adeka Stub LA-36 (C-1) (manufactured by ADEKA Corporation) were dry-blended. The mixture was then melt-kneaded under the following conditions using a 25 mm extruder "2D30W2" manufactured by Toyo Seiki Seisakusho Co., Ltd., and pelletized to obtain resin composition pellets. The content of phosphate ions, alkali metal ions, and boron elements in the obtained resin composition pellets was measured using the method described in evaluation method (1) above. The phosphate ion content was 40 ppm, the sodium ion content was 150 ppm, and the boron element content was 180 ppm. Set temperature C1 / C2 / C3 / C4 / C5 / Die = 180 / 210 / 210 / 210 / 210 / 210℃ Screw rotation speed: 100 rpm Discharge amount: 6.0kg / hour

[0070] Using the obtained resin composition pellets, single-layer films were fabricated under the following conditions using a 20mm single-screw extruder "D2020" manufactured by Toyo Seiki Seisakusho Co., Ltd. (D(mm)=20, L / D=20, compression ratio=3.5, screw: full flight). The obtained single-layer films were evaluated for molecular weight retention, light transmittance, impact strength, and coloration before and after the weather resistance test using the methods described in evaluation methods (2) to (6) above. The results are shown in Table 1. Temperature settings: C1 / C2 / C3 / Die = 180 / 210 / 210 / 210℃ Screw rotation speed: 100 rpm Discharge amount: 3.0kg / hour Take-up roll temperature: 80℃ Roller retrieval speed: 1.5 m / min Film thickness: 100 μm

[0071] Examples 2-12, Comparative Examples 1-10 Resin composition pellets and single-layer films were prepared and evaluated in the same manner as in Example 1, except that the type of EVOH (A), the type and content of hindered amine compounds (B), the type and content of benzotriazole compounds, and the content of boron compounds were changed as shown in Table 1. The results are shown in Table 1.

[0072] The single-layer films obtained in Example 1 and Comparative Example 1 were subjected to weather resistance tests according to the method described in Evaluation Method (3) above, and then the oxygen permeability was measured in accordance with JIS K 7126:2006 (isobaric method). The single-layer film obtained in Example 1 had lower (superior) oxygen permeability after the weather resistance test than the single-layer film obtained in Comparative Example 1. It is presumed that because Example 1 contains specific amounts of hindered amine compound (B) and benzotriazole compound (C), it had superior weather resistance compared to Comparative Example 1, which does not contain hindered amine compound (B) and benzotriazole compound (C), and was able to maintain sufficient oxygen permeability even after the weather resistance test.

[0073] Example 13 In Example 1, dry EVOH pellets (EVOH-2) were obtained in the same manner as in Example 1, except that hydrated EVOH pellets with an ethylene unit content of 44 mol% and a degree of saponification of 99.9 mol% were used as the hydrated EVOH pellets. Resin composition pellets and single-layer films were then prepared and evaluated. The results are shown in Table 1.

[0074] Example 14 To 93.5 parts by mass of the dried EVOH pellets obtained in Example 1, 3.7 parts by mass of Tinuvin NOR 371 (B-1, manufactured by BASF Japan Ltd.) and 2.8 parts by mass of Adeka Stub LA-36 (C-1, manufactured by ADEKA Corporation) were dry-blended. The mixture was then melt-kneaded under the following conditions using a 25mm extruder "2D30W2" manufactured by Toyo Seiki Seisakusho Co., Ltd., and then pelletized to obtain masterbatch pellets. Temperature settings: C1 / C2 / C3 / C4 / C5 / Die = 180 / 210 / 210 / 210 / 210 / 210℃ Screw rotation speed: 100 rpm Discharge amount: 6.0kg / hour

[0075] Furthermore, 90 parts by mass of dried EVOH pellets obtained in Example 1 and 10 parts by mass of masterbatch pellets were dry-blended, and then a single-layer film was formed and evaluated using the same method as in Example 1. The results are shown in Table 1.

[0076] The dried EVOH obtained in Example 1 and the masterbatch pellets obtained above were measured for phosphate ions, alkali metal ions, boron, and acetic acid content using the methods described in evaluation methods (1) and (2) above. The content of phosphate ions, sodium ions, boron, and acetic acid in both the dried EVOH pellets and the masterbatch pellets was 40 ppm, 150 ppm, 180 ppm, and 100 ppm, respectively. Based on these results, it was assumed that the dry blend product also contains the same amounts of phosphate ions, sodium ions, boron, and acetic acid as described above.

[0077] [Table 1]

[0078] Example 15 Using the resin composition pellets from Example 1 as the intermediate layer, polyethylene "Novatec® PE LF128" (PE) manufactured by Nippon Polyethylene Co., Ltd. as the thermoplastic resin layer, and adhesive polyolefin "Admer® NF518" (Ad) manufactured by Mitsui Chemicals, Inc. as the adhesive layer, three types of five-layer laminates (PE / Ad / resin composition layer / Ad / PE = 40 μm / 10 μm / 20 μm / 10 μm / 40 μm) were obtained under the following conditions. The film-forming equipment consisted of an extruder with a film-forming die followed by a temperature-controllable take-up roll, and the obtained multilayer structure was wound up on a winding machine. <Film forming conditions> Extruder for resin composition pellets: Single-screw extruder (Laboratory model ME type CO-EXT, manufactured by Toyo Seiki Co., Ltd.) Bore diameter 20mmφ, L / D=20, Screw, Full Flight Type Supply unit / Compression unit / Measuring unit / Die = 180 / 210 / 210 / 210℃ Extruder for PE: Single-screw extruder (GT-32-A, manufactured by Plastics Engineering Laboratory Co., Ltd.) Bore diameter 32mmφ, L / D=28, Screw, Full Flight Type Supply unit / Compression unit / Measuring unit / Die = 180 / 220 / 220 / 220℃ Extruder for AD: Single-screw extruder (SZW20GT-20MG-STD, manufactured by Technovel Corporation) Bore diameter 20mmφ, L / D=20, Screw, Full Flight Type Supply unit / Compression unit / Measuring unit / Die = 180 / 220 / 220 / 220℃ Die: 300mm wide coat hanger die (manufactured by Plastics Engineering Laboratory Co., Ltd.) Take-up roll temperature: 60℃

[0079] The resulting multilayer structure exhibited excellent weather resistance and demonstrated no problems even when stored outdoors for extended periods.

Claims

1. A resin composition, Ethylene-vinyl alcohol copolymer (A) with an ethylene unit content of 20 to 60 mol%, A hindered amine compound (B) having a 2,2,6,6-tetraalkylpiperidine ring structure and an alkoxy group bonded to the nitrogen atom in the structure, and contains a benzotriazole compound (C), The ethylene-vinyl alcohol copolymer (A) contains 100 parts by mass of the hindered amine compound (B), and the benzotriazole compound (C) contains 0.2 to 5 parts by mass of the hindered amine compound (B) and 0.1 to 5 parts by mass of the benzotriazole compound (C). A 100 μm thick film made of the aforementioned resin composition is subjected to a weathering test in which it is irradiated with light at 63°C, 50% RH, and an irradiation intensity of 1000 W / m² for 50 hours. The retention rate of the weight-average molecular weight (Mw) after the test is 90% or higher, and the retention rate of the number-average molecular weight (Mn) is 80% or higher. Resin composition.

2. The resin composition according to claim 1, wherein the mass ratio (C) / (B) of the benzotriazole compound (C) to the hindered amine compound (B) is 0.2 to 3.

5.

3. The resin composition according to claim 1, wherein the molecular weight of the hindered amine compound (B) is 1000 or more.

4. The resin composition according to claim 1, wherein the benzotriazole compound (C) has an aromatic ring to which a hydroxyl group is bonded, and the aromatic ring has a structure in which it is bonded to a nitrogen atom constituting a benzotriazole ring.

5. The resin composition according to claim 4, wherein the aromatic ring to which the hydroxyl group is bonded has two or more substituents other than the benzotriazole ring and the hydroxyl group.

6. The resin composition according to claim 1, wherein the benzotriazole compound (C) has a halogen group on the benzotriazole ring.

7. The resin composition according to claim 1, further comprising phosphate ions in an amount of 5 ppm to 200 ppm and alkali metal ions in an amount of 10 ppm to 400 ppm.

8. The resin composition according to claim 1, further comprising a boron compound in an amount of 50 to 400 ppm in terms of boron element.

9. The resin composition according to claim 1, wherein a film with a thickness of 100 μm made from the resin composition according to claim 1 has a light transmittance of 50% or less at a wavelength of 300 nm, as measured in accordance with JIS K 7361-1:1997.

10. For a 100 μm thick film made of the resin composition described in claim 1, the light transmittance at a wavelength of 300 nm, measured in accordance with JIS K 7361-1:1997, was measured at 63°C, 50% RH, and an irradiation intensity of 1000 W / m². ２ The resin composition according to claim 1, wherein the difference in light transmittance before and after a weathering test in which light irradiation is performed for 50 hours (transmittance after weathering test (%)) - (transmittance before weathering test (%)) is 4.0% or less.

11. A laminate comprising a layer made of the resin composition according to any one of claims 1 to 10.

12. An industrial film comprising the laminate described in claim 11.

13. A pipe comprising the laminate according to claim 11.

14. A masterbatch for producing the resin composition according to any one of claims 1 to 10, It contains an ethylene-vinyl alcohol copolymer (A) with an ethylene unit content of 20 to 60 mol%, a hindered amine compound (B) having a 2,2,6,6-tetraalkylpiperidine ring structure and an alkoxy group bonded to the nitrogen atom in the structure, and a benzotriazole compound (C). A masterbatch containing 100 parts by mass of the ethylene-vinyl alcohol copolymer (A), 2 to 20 parts by mass of the hindered amine compound (B), and 1 to 15 parts by mass of the benzotriazole compound (C).

15. A step of obtaining a masterbatch by pre-melt-kneading 100 parts by mass of an ethylene-vinyl alcohol copolymer (A) having an ethylene unit content of 20 to 60 mol%, 2 to 20 parts by mass of a hindered amine compound (B) having a 2,2,6,6-tetraalkylpiperidine ring structure and an alkoxy group bonded to the nitrogen atom in the structure, and 1 to 15 parts by mass of a benzotriazole compound (C), The process includes the step of melt-kneading the obtained masterbatch with an ethylene-vinyl alcohol copolymer (A) to obtain a resin composition containing 0.2 to 5 parts by mass of the hindered amine compound (B) and 0.1 to 5 parts by mass of the benzotriazole compound (C) per 100 parts by mass of the ethylene-vinyl alcohol copolymer (A), A method for producing a resin composition, wherein a 100 μm thick film made of the resin composition is irradiated with light at 63°C, 50% RH, and at an irradiation intensity of 1000 W / m² for 50 hours, and after a weathering test, the retention rate of the weight-average molecular weight (Mw) is 90% or more, and the retention rate of the number-average molecular weight (Mn) is 80% or more.

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