Fiber-reinforced ethylene-vinyl alcohol copolymer sheet or belt

Abstract

A fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape which is characterized by containing an ethylene-vinyl alcohol copolymer (A) and continuous fibers, and which is characterized in that the continuous fibers are oriented in the MD direction such that the degree of orientation determined by a specific formula is 2 or less on average. As a result, a fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape having excellent bending strength and excellent hydrogen barrier properties is provided.

Description

Technical Field

[0001] The present invention relates to a fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape, a molded article using the same, and a method for producing the molded article. Background Art

[0002] To improve fuel efficiency, structural components, particularly automotive body parts, require materials with high specific strength. Fiber-reinforced plastics (FRP), while having a lower specific gravity than metal materials like steel and aluminum, possess comparable strength and have recently begun to be used in automotive body parts. Thermosetting resins are typically used as the matrix for FRP, but these resins suffer from issues such as long molding cycles and difficulty in post-processing and recycling, such as welding of molded parts. Consequently, the use of thermoplastic resins has been studied as alternatives. Among these, polyamides are attracting attention due to their high adhesion to carbon fibers, resulting in high-strength composite materials (Patent Document 1).

[0003] Prior art literature Patent Literature Patent Document 1: International Publication No. 2015 / 046290. Summary of the Invention

[0004] Problems to be solved by the invention As mentioned above, the use of polyamide as a matrix for FRP has attracted considerable attention. However, when polyamide is used in applications requiring gas barrier properties, particularly hydrogen barrier properties, it is necessary to use other components exhibiting even higher gas barrier properties. Furthermore, polyamide-based FRPs sometimes lack sufficient flexural strength. However, research on barrier materials using resins other than polyamide as FRP matrices has been largely absent, and suitable resins for FRP matrices remain unknown.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape having excellent flexural strength and excellent hydrogen gas barrier properties.

[0006] Means used to solve problems As a result of intensive research, the present inventors discovered that a fiber-reinforced EVOH sheet or tape containing a specific ethylene-vinyl alcohol copolymer (hereinafter sometimes abbreviated as "EVOH") and continuous fibers, where the continuous fibers satisfy a specific degree of orientation, can solve the aforementioned problems. Based on this understanding, further research was conducted, leading to the completion of the present invention.

[0007] That is, the present invention is achieved by providing the following technical solutions.

[0008] [1] A fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape (hereinafter sometimes abbreviated as "fiber-reinforced EVOH sheet or tape") comprising an ethylene-vinyl alcohol copolymer (A) (hereinafter sometimes abbreviated as "EVOH (A)") and continuous fibers, wherein the continuous fibers are oriented in the MD direction so that the average orientation degree determined by the following formula (1) is 2 or less.

[0009] Orientation degree = (F) / (S) (1) (In formula (1), (F) is the path length of the shortest path from (p) to (q) via only continuous fibers, when any intersection point between one of the two sides in the TD direction and the continuous fibers is defined as intersection point (p), and any intersection point between the other side in the TD direction that can be reached from (p) via only continuous fibers is defined as intersection point (q); and (S) is the straight-line distance between (p) and (q). If the continuous fibers intersect with each other when observing the square region in the thickness direction of the fiber-reinforced EVOH sheet or tape, the continuous fibers are actually separated from each other in the thickness direction. Even when they are not in contact with each other, the continuous fibers are considered to form a continuous path.) [2] The fiber-reinforced EVOH sheet or tape according to [1], wherein the continuous fiber is at least one selected from the group consisting of carbon fiber, glass fiber, aramid fiber, wholly aromatic polyester fiber, ceramic fiber, and metal fiber; [3] The fiber-reinforced EVOH sheet or tape according to [1] or [2], wherein the ethylene unit content of the EVOH (A) is 15 mol% or more and 50 mol% or less; [4] The fiber-reinforced EVOH sheet or tape according to any one of [1] to [3], wherein the content of EVOH (A) is 20% by mass or more and 80% by mass or less, and the content of the continuous fibers is 20% by mass or more and 80% by mass or less; [5] The fiber-reinforced EVOH sheet or tape according to any one of [1] to [4], further comprising an acid-modified polyolefin (B); [6] A molded article comprising the fiber-reinforced EVOH sheet or tape according to any one of [1] to [5]; [7] The molded article according to [6], which is a pressure vessel; [8] The molded article according to [7], which is a hydrogen tank; [9] A method for producing a molded article according to [8], comprising: winding or laminating a fiber-reinforced EVOH sheet or tape on a core rod by a winding molding method or a braiding molding method;

[10] The production method according to [9], comprising: winding or laminating a fiber-reinforced sheet or tape of a thermoplastic resin different from the ethylene-vinyl alcohol copolymer around the outside of a molded article comprising a fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape;

[11] A fiber-reinforced EVOH sheet comprising the fiber-reinforced EVOH sheet or tape according to any one of [1] to [5];

[12] A molded article comprising the fiber-reinforced EVOH sheet of

[11] ;

[13] The molded article according to

[12] , which is a hydrogen tank;

[14] A molded article comprising the fiber-reinforced EVOH sheet or tape according to any one of [1] to [5], and a fiber-reinforced sheet or tape containing a resin that reacts with EVOH;

[15] The molded article according to

[14] , wherein the resin reacting with EVOH is a polyamide resin.

[0010] Effects of the Invention According to the present invention, a fiber-reinforced EVOH sheet or tape having excellent flexural strength and excellent hydrogen gas barrier properties can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram showing a square area obtained by cutting out a fiber-reinforced EVOH sheet or tape by 2 mm in the TD direction and by 2 mm in the MD direction, as viewed from the thickness direction of the fiber-reinforced EVOH sheet or tape. DETAILED DESCRIPTION

[0012] The fiber-reinforced EVOH sheet or tape of the present invention contains EVOH (A) and continuous fibers, wherein the continuous fibers are oriented in the MD direction so that the average orientation degree determined by the following formula (1) is 2 or less.

[0013] Orientation degree = (F) / (S) (1) (In formula (1), (F) and (S) are as defined above) In this specification, a "sheet" refers to an object with a width (TD) of 250 mm or greater, and a "tape" refers to an object with a width of less than 250 mm. In this specification, "continuous fibers" refer to substantially uncut continuous fibers, such as fibers with an aspect ratio (the ratio of the fiber length in the axial direction to the fiber diameter) of 100 or greater, or fibers with a length of 10 mm or greater. It should be noted that even if the fiber-reinforced EVOH sheet or tape of the present invention is cut so that the continuous fibers within it have an aspect ratio of less than 100 or less than 10 mm, these fibers are still considered to be substantially uncut continuous fibers within the fiber-reinforced EVOH sheet or tape, i.e., they are considered to include "continuous fibers." The thickness of the fiber-reinforced EVOH sheet or tape of the present invention is preferably 5 mm or less, more preferably 1 mm or less, even more preferably 0.5 mm or less, and particularly preferably 0.3 mm or less. Alternatively, the thickness may be, for example, 0.05 mm or greater. A thickness of 5 mm or less reduces the risk of thickness unevenness during the production of the molded article of the present invention. Furthermore, when the thickness is 0.05 μm or more, the molded article of the present invention can be easily and efficiently produced.

[0014] use Figure 1 The method for obtaining the degree of orientation in the present invention will be described. Figure 1 It is a schematic diagram of a square area formed by cutting 2 mm in the TD direction and 2 mm in the MD direction of the fiber-reinforced EVOH sheet or tape as viewed from the thickness direction of the aforementioned fiber-reinforced EVOH sheet or tape. (p) is an arbitrary intersection of one of the two sides in the TD direction of the aforementioned square area and the continuous fiber. In addition, (q) is an arbitrary intersection of the other side in the TD direction that can be reached from (p) only by passing through the continuous fiber and the continuous fiber. (F) in formula (1) is the path length of the shortest path among the paths from (p) only by passing through the continuous fiber to (q), which is Figure 1 The length of the thick solid line in . In addition, (S) is the straight-line distance between (p) and (q), which is Figure 1The length of the dashed line in . When observing the square region through the thickness of the fiber-reinforced EVOH sheet or tape, if the continuous fibers intersect, they are actually separated in the thickness direction. When they are not in contact, the continuous fibers are considered to form a continuous path. Regarding the fiber-reinforced EVOH sheet or tape of the present invention, the continuous fibers are oriented in the MD direction such that the average (number average) of the orientation degrees ((F) / (S)) obtained for all conceivable combinations of (p) and (q) is 2 or less, preferably 1.8 or less, more preferably 1.6 or less, and even more preferably 1.5 or less. The orientation degree may be 1.0 or greater, 1.1 or greater, or 1.2 or greater. The average orientation degree can be obtained by thinning the continuous fibers using 3D volume mapping software from an image obtained using a 3D X-ray CT scanner, calculating the orientation degrees ((F) / (S)) for all (p) and (q), and then taking the number average. The fiber-reinforced EVOH sheet or tape of the present invention tends to exhibit excellent bending strength by satisfying the above-mentioned orientation degree.

[0015] (EVOH(A)) The fiber-reinforced EVOH sheet or tape of the present invention contains EVOH (A). The inclusion of EVOH (A) in the fiber-reinforced EVOH sheet or tape of the present invention not only improves oxygen and hydrogen barrier properties, but also, by ensuring that the average orientation degree of the continuous fibers is 2 or less and containing EVOH (A), tends to exhibit excellent flexural strength. It should be noted that because the sheet or tape tends to exhibit even greater flexural strength in the MD direction, even greater flexural strength can be achieved by, for example, stacking the sheets or tapes in 90° rotations or stacking them in various orientations.

[0016] EVOH (A) is generally obtained by saponifying an ethylene-vinyl ester copolymer. The production and saponification of ethylene-vinyl ester copolymers can be carried out by known methods. A representative example of vinyl esters is vinyl acetate, but other fatty acid vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate can also be used.

[0017] The ethylene unit content of EVOH (A) is preferably 15 mol% or more, more preferably 20 mol% or more, and even more preferably 24 mol% or more. Furthermore, the ethylene unit content of EVOH (A) is preferably 50 mol% or less, more preferably 35 mol% or less, even more preferably 32 mol% or less, and particularly preferably 30 mol% or less. Using EVOH (A) with a low ethylene unit content can achieve particularly excellent hydrogen barrier properties and flexural strength. Generally, EVOH (A) with a low ethylene unit content tends to exhibit increased rigidity and cracking when heated and deformed. However, in the present invention, by combining it with continuous fibers having a specific degree of orientation, the specific effect of further improving flexural strength is achieved when EVOH (A) with a low ethylene unit content is included. Furthermore, cracking is naturally suppressed. Therefore, problems that are particularly prominent when using EVOH (A) with a low ethylene unit content (such as cracking due to increased rigidity) can be resolved by combining it with continuous fibers. The ethylene unit content of EVOH (A) can be determined by nuclear magnetic resonance (NMR).

[0018] The saponification degree of the vinyl ester component of EVOH (A) is preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 99 mol% or more. By setting the saponification degree to 90 mol% or more, it is possible to improve gas barrier properties, etc. In addition, the saponification degree of EVOH (A) may be 100 mol% or less, or 99.99 mol% or less. The saponification degree of EVOH (A) can be determined by 1 The H-NMR measurement is performed by measuring the peak area of ​​hydrogen atoms contained in the vinyl ester structure and the peak area of ​​hydrogen atoms contained in the vinyl alcohol structure. If the saponification degree of EVOH (A) is within the above range, the gas barrier properties tend to be good.

[0019] EVOH (A) may contain monomer units other than ethylene, vinyl ester, and vinyl alcohol, as long as they do not impair the effects of the present invention. In particular, the introduction of a modifying group having a specific structure and containing a primary hydroxyl group can sometimes achieve a high level of both gas barrier properties and moldability in 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 no such units are present. Examples of such other monomers include olefins such as propylene, butene, pentene, and hexene; 3-acyloxy-1-propylene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diacyloxy-2-methyl-1-butene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diacyloxy-1-pentene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy-1-pentene, 3 ...1-pentene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diacyloxy-2-methyl-1-butene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diacyloxy-1-pentene, Ester-containing olefins such as 1-hexene, 5,6-diacyloxy-1-hexene, and 1,3-diacetoxy-2-methylenepropane, or their saponified products; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, and itaconic acid, or their anhydrides, salts, or monoalkyl esters 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-methacryloyloxypropylmethoxysilane; alkyl vinyl ethers, vinyl ketone, N-vinylpyrrolidone, vinyl chloride, and vinylidene chloride.

[0020] EVOH (A) can be modified as needed by urethanization, acetalization, cyanoethylation, oxyalkyleneization, etc. Oxyalkyleneization can be performed using epoxy compounds, such as ethylene oxide (ethylene oxide), propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, 3-methyl-1,2-butylene oxide, 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, ethylbenzene, 1-phenyl-1,2-propane, 3-phenyl-1,2-epoxypropylene, various alkyl glycidyl ethers, various alkylene glycol monoglycidyl ethers, various alkenyl glycidyl ethers, various oxirane alcohols such as glycidol, various oxirane alkanes, various oxirane olefins, etc. Among them, 1,2-butylene oxide, 2,3-butylene oxide, propylene oxide, ethylene oxide, or glycidol is preferred, and propylene oxide or glycidol is more preferred.

[0021] As the EVOH (A), one type may be used alone, or two or more types of EVOHs different in ethylene unit content, saponification degree, copolymer components, presence or absence of modification, type of modification, etc. may be used as a mixture.

[0022] The MFR of EVOH (A) at 210°C and a load of 2160 g is preferably 0.1 g / 10 min or higher, more preferably 0.5 g / 10 min or higher, and even more preferably 1 g / 10 min or higher. Meanwhile, the MFR of EVOH (A) is preferably 50 g / 10 min or lower, more preferably 20 g / 10 min or lower, and even more preferably 10 g / 10 min or lower. By setting the MFR of EVOH (A) within this range, the resulting resin composition improves melt kneading and melt moldability.

[0023] (Continuous Fiber) The fiber-reinforced EVOH sheet or tape of the present invention contains continuous fibers. By containing continuous fibers, the fiber-reinforced EVOH sheet or tape of the present invention tends to exhibit significantly improved flexural strength.

[0024] Examples of the continuous fibers include inorganic fibers such as carbon fibers, glass fibers, silicon carbide fibers, alumina fibers, ceramic fibers, basalt fibers, and metal fibers (e.g., gold, silver, copper, iron, nickel, titanium, stainless steel, etc.); and organic fibers such as wholly aromatic polyester fibers, polyphenylene sulfide fibers, aramid fibers, polysulfonamide fibers, phenolic resin fibers, polyimide fibers, and fluorocarbon fibers. These fibers may be used alone or in combination of two or more. From the perspectives of mechanical properties and availability, at least one selected from carbon fibers, glass fibers, aramid fibers, wholly aromatic polyester fibers, ceramic fibers, and metal fibers is preferred, with carbon fibers being more preferred. The continuous fibers may be coated with a surface modifier such as a coupling agent or a sizing agent.

[0025] The number average fiber diameter of the continuous fibers is preferably 1 to 100 μm, more preferably 3 to 50 μm, and even more preferably 5 to 10 μm. Continuous fibers having, for example, about 500 to 30,000 filaments can be used depending on the intended purpose.

[0026] From the perspective of strength, the fiber-reinforced EVOH sheet or tape of the present invention preferably contains 20 to 80% by mass of continuous fibers, more preferably 30 to 70% by mass. A content of 20% or more ensures sufficient strength, while a content of 80% or less allows sufficient impregnation of the continuous fibers with EVOH.

[0027] (Acid-modified polyolefin (B)) The fiber-reinforced EVOH sheet or tape of the present invention may contain an acid-modified polyolefin (B). If the fiber-reinforced EVOH sheet or tape of the present invention contains an acid-modified polyolefin (B), low-temperature flexibility is improved. Examples of the acid-modified polyolefin (B) include polyethylene, polypropylene, ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-1-hexene copolymers, ethylene-4-methyl-1-pentene copolymers, ethylene-1-octene copolymers, ethylene-1-butene-1-hexene copolymers, ethylene-1-butene-4-methyl-1-pentene copolymers, and ethylene-1-butene-1-octene copolymers, and other acid-modified copolymers. From the perspective of crack resistance of the resulting multilayer structure, at least one selected from an acid-modified ethylene-1-butene copolymer and an acid-modified ethylene-propylene copolymer is preferred, with an acid-modified ethylene-1-butene copolymer being more preferred.

[0028] Examples of the acid-modified group include unsaturated carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride, or their anhydrides. From the viewpoint of reactivity with EVOH (A), maleic anhydride modification is preferred.

[0029] When the fiber-reinforced EVOH sheet or tape of the present invention contains an acid-modified polyolefin (B), the mass ratio (B / A) of the acid-modified polyolefin (B) to the EVOH (A) is preferably 1 / 99 or greater, more preferably 3 / 97 or greater, and even more preferably 5 / 95 or greater. Furthermore, the mass ratio (B / A) is preferably 50 / 50 or less, more preferably 40 / 60 or less, and even more preferably 30 / 70 or less. When the mass ratio (B / A) is within this range, gas barrier properties tend to be maintained while imparting flexibility.

[0030] (Other ingredients) The fiber-reinforced EVOH sheet or tape of the present invention may contain other components (components other than EVOH (A), continuous fibers and acid-modified polyolefin (B)) such as resins, carboxylic acid compounds, phosphoric acid compounds, boron compounds, metal salts, heat stabilizers, antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, desiccants, inorganic substances other than continuous fibers, nucleating agents, crystallization retarding materials, anti-hydrolysis agents, free radical inhibitors, matting agents, ultraviolet absorbers, flame retardants, various fibers other than continuous fibers, and other reinforcing agents, as long as they are within the range that does not impair the effects of the present invention.

[0031] Examples of resins other than EVOH (A) and the acid-modified polyolefin (B) include unmodified polyolefins such as unmodified polyethylene, unmodified polypropylene, and unmodified ethylene-α-olefin copolymers; polyamides; polyvinyl chloride; polyvinylidene chloride; polyesters; polystyrene; epoxy resins; acrylic resins; urethane resins; and polyester resins. Among these, unmodified polyolefins are preferred due to their excellent compatibility with the acid-modified polyolefin (B), and unmodified ethylene-α-olefin copolymers are more preferred. When the fiber-reinforced EVOH sheet or tape of the present invention contains a resin other than EVOH (A) and the acid-modified polyolefin (B), the content is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and particularly preferably 0.1% by mass or less, to ensure that the effects of the present invention are not impaired. The fiber-reinforced EVOH sheet or tape of the present invention may also contain no resin other than EVOH (A) and the acid-modified polyolefin (B).

[0032] If the fiber-reinforced EVOH sheet or tape of the present invention contains a carboxylic acid compound, it shows a tendency to suppress coloration during melt molding. The carboxylic acid compound can be a monocarboxylic acid, a polycarboxylic acid, or a combination thereof. The carboxylic acid compound can be an ion, and the carboxylic acid ion can form a salt with a metal ion.

[0033] If the fiber-reinforced EVOH sheet or tape of the present invention contains a phosphate compound, it shows a tendency to suppress coloration during melt molding. The phosphate compound is not particularly limited, and various acids such as phosphoric acid and phosphorous acid, and their salts, etc. can be used. As a phosphate, it can be included in any form of dihydrogen phosphate, monohydrogen phosphate, or phosphate, preferably dihydrogen phosphate. Its cationic species are also not particularly limited, and are preferably alkali metal salts. Among them, sodium dihydrogen phosphate and potassium dihydrogen phosphate are preferred. When the fiber-reinforced EVOH sheet or tape of the present invention contains a phosphate compound, the content of the phosphate compound is preferably 5 ppm or more and 200 ppm or less in terms of phosphate radical conversion. If the content of the phosphate compound is 5 ppm or more, it shows a tendency to have good coloration resistance during melt molding. On the other hand, if the content of the phosphate compound is 200 ppm or less, there is a tendency to have good melt moldability, and more preferably 160 ppm or less.

[0034] If the fiber-reinforced EVOH sheet or tape of the present invention contains a boron compound, it tends to suppress torque fluctuations during heating and melting. Boron compounds are not particularly limited, and examples include boric acids, boric esters, borate salts, and boron hydrides. Specifically, examples of boric acids include orthoboric acid, metaboric acid, and tetraboric acid; examples of boric esters include triethyl borate and trimethyl borate; and examples of borate salts include alkali metal salts, alkaline earth metal salts, and borax of the various boric acids mentioned above. Of these, orthoboric acid (hereinafter sometimes referred to as boric acid) is preferred. When the fiber-reinforced EVOH sheet or tape of the present invention contains a boron compound, the boron compound content, calculated as the boron element, is preferably 20 ppm or more and 2000 ppm or less. A boron compound content of 20 ppm or more tends to suppress torque fluctuations during heating and melting, and more preferably 50 ppm or more. On the other hand, a boron compound content of 2000 ppm or less tends to maintain good formability, and more preferably 1000 ppm or less is preferred.

[0035] If the fiber-reinforced EVOH sheet or tape of the present invention contains an alkali metal salt, it tends to have good interlayer adhesion with other resin layers. The cationic species of the alkali metal salt is not particularly limited, and sodium salts or potassium salts are suitable. The anionic species of the alkali metal salt is also not particularly limited. It can be added in the form of carboxylates, carbonates, bicarbonates, phosphates, hydrogenphosphates, borates, hydroxides, etc. When the fiber-reinforced EVOH sheet or tape of the present invention contains an alkali metal salt, the content of the alkali metal salt is preferably 10 ppm or more and 500 ppm or less in terms of metal element conversion. If the content of the alkali metal salt is 10 ppm or more, it tends to have good interlayer adhesion, and more preferably 50 ppm or more. On the other hand, if the content of the alkali metal salt is 500 ppm or less, it tends to have excellent melt stability, and more preferably 300 ppm or less.

[0036] If the fiber-reinforced EVOH sheet or tape of the present invention contains an alkaline earth metal salt, it shows a tendency to suppress degradation during repeated melt molding of the molded body and to suppress the generation of degraded products such as gel. The cationic species of the alkaline earth metal salt is not particularly limited, and magnesium salts or calcium salts are suitable. The anionic species of the alkaline earth metal salt is also not particularly limited. It can be added in the form of carboxylates, carbonates, bicarbonates, phosphates, hydrogen phosphates, borates, hydroxides, etc.

[0037] The fiber-reinforced EVOH sheet or tape of the present invention preferably contains a heat stabilizer. Examples of the heat stabilizer include phenolic heat stabilizers, phosphorus heat stabilizers, sulfur heat stabilizers, amine heat stabilizers, copper heat stabilizers, and derivatives thereof.

[0038] Examples of the phenolic heat stabilizer include 2,2-thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], triethylene glycol bis(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, hexamethylenebis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide), phenyl) propionate), 3,9-bis[1,1-dimethyl-2-[β{(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, etc.

[0039] Examples of the phosphorus-based heat stabilizer include monosodium phosphate, disodium phosphate, trisodium phosphate, sodium phosphite, calcium phosphite, magnesium phosphite, manganese phosphite, triphenyl phosphite, trioctadecyl phosphite, tridecyl phosphite, trinonylphenyl phosphite, diphenylisodecyl phosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite), tetrakis(2,4-di-tert-butyl-5-methylphenyl)-4,4'-diphenylene diphosphonite. dioxaphosphine ester, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl)phosphite, 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]-dioxaphosphoheptane, etc.

[0040] Examples of the sulfur-based heat stabilizer include distearyl 3,3'-thiodipropionate, pentaerythritol tetrakis(3-laurylthiopropionate), 2-mercaptobenzimidazole, didodecyl 3,3'-thiodipropionate, didecyl 3,4'-thiodipropionate, and 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediyl ester.

[0041] Examples of the amine-based heat stabilizer include 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (e.g., "NOCRAC CD" manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), N,N'-di-2-naphthyl-p-phenylenediamine (e.g., "NOCRAC White" manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), N,N'-diphenyl-p-phenylenediamine (e.g., "NOCRACDP" manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), N-phenyl-1-naphthylamine (e.g., "NOCRAC PA" manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), N-phenyl-N'-isopropyl-p-phenylenediamine (e.g., "NOCRAC 810-NA" manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (e.g., "NOCRAC 6C”, etc.), N-phenyl-N'-(3-methacryloyloxy-2-hydroxypropyl)-p-phenylenediamine ("NOCRAC G-1" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., etc.), etc.

[0042] Examples of the copper-based heat stabilizer include copper halides such as copper iodide and derivatives thereof.

[0043] In particular, the fiber-reinforced EVOH sheet or tape of the present invention preferably contains at least one of a phenolic heat stabilizer, a phosphorus heat stabilizer, and an amine heat stabilizer, and more preferably contains a phenolic heat stabilizer.

[0044] If the fiber-reinforced EVOH sheet or tape of the present invention contains an antioxidant, degradation is suppressed, and the gas barrier properties and crack resistance of the fiber-reinforced EVOH sheet or tape of the present invention are further improved. As the antioxidant, a compound having a hindered phenol group, a compound having a hindered amine group, or other known antioxidants can be used. Specific examples of antioxidants include 2,5-di-tert-butylhydroquinone, 2,6-di-tert-butyl-p-cresol, 4,4'-thiobis(6-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), octadecyl 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, 4,4'-thiobis(6-tert-butylphenol), pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide]. Furthermore, the antioxidants described in paragraphs

[0029] and

[0033] to

[0035] of JP-A-2015-27813 can also be suitably used. The content of the antioxidant in the fiber-reinforced EVOH sheet or tape of the present invention is, for example, preferably 0.001 mass % to 4 mass %, more preferably 0.01 mass % to 2 mass %, and even more preferably 0.1 mass % to 1 mass %.

[0045] Examples of the ultraviolet absorber include ethyl 2-cyano-3',3'-diphenylacrylate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, and 2,2'-dihydroxy-4-methoxybenzophenone.

[0046] Examples of plasticizers include dimethyl phthalate, diethyl phthalate, dioctyl phthalate, wax, liquid paraffin, and phosphate esters. Examples of antistatic agents include pentaerythritol monostearate, sorbitan monopalmitate, sulfated polyolefins, polyethylene oxide, and carbowax. Examples of lubricants include ethylene bisstearamide and butyl stearate. Examples of colorants include carbon black, phthalocyanine, quinacridone, indoline, azo pigments, and Indian red. Examples of fillers include glass fiber, asbestos, wollastonite, and calcium silicate. Examples of the inorganic substance include carbon nanotubes, fullerenes, talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, silica, bentonite, alumina silicate, silicon oxide, magnesium oxide, aluminum oxide, zirconium oxide, titanium oxide, iron oxide, calcium carbonate, magnesium carbonate, dolomite, calcium sulfate, barium sulfate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black, and graphite. It should be noted that among the compounds exemplified as fillers and inorganic substances, those having a fibrous shape are all discontinuous fibers.

[0047] In the fiber-reinforced EVOH sheet or tape of the present invention, the proportion of EVOH (A) in the resin component other than the continuous fibers is preferably 70% by mass or greater, more preferably 80% by mass or greater, even more preferably 90% by mass or greater, and can be 95% by mass or greater, 98% by mass or greater, 99% by mass or greater, or 100% by mass. When the fiber-reinforced EVOH sheet or tape of the present invention contains an acid-modified polyolefin (B), the proportion of the combined EVOH (A) and acid-modified polyolefin (B) in the resin component other than the continuous fibers is preferably 70% by mass or greater, more preferably 80% by mass or greater, even more preferably 90% by mass or greater, and can be 95% by mass or greater, 98% by mass or greater, 99% by mass or greater, or 100% by mass.

[0048] In the fiber-reinforced EVOH sheet or tape of the present invention, the proportion of EVOH (A) and continuous fibers is preferably 70% by mass or greater, more preferably 80% by mass or greater, even more preferably 90% by mass or greater, and can be 95% by mass or greater, 98% by mass or greater, 99% by mass or greater, or 100% by mass. When the fiber-reinforced EVOH sheet or tape of the present invention contains an acid-modified polyolefin (B), the proportion of EVOH (A), acid-modified polyolefin (B), and continuous fibers in the fiber-reinforced EVOH sheet or tape of the present invention is preferably 70% by mass or greater, more preferably 80% by mass or greater, even more preferably 90% by mass or greater, and can be 95% by mass or greater, 98% by mass or greater, 99% by mass or greater, or 100% by mass.

[0049] (Method for Manufacturing Fiber-Reinforced EVOH Sheet or Tape) The fiber-reinforced EVOH sheet or tape of the present invention can be produced according to a known method for producing so-called UD sheets or tapes (for example, the method described in Japanese Patent Application Laid-Open No. 2015-30119, in which the polyamide is replaced with EVOH and the conditions are adjusted). For example, it can be produced by overlapping EVOH (A) (and, if necessary, a resin composition containing an acid-modified polyolefin (B) and other components) with continuous fibers and then heating them to impregnate the continuous fibers with the EVOH (A) (and, if necessary, a resin composition containing an acid-modified polyolefin (B) and other components). However, in order to achieve a specific degree of orientation, it is preferable to include a step of uniformly draping the EVOH (A) (and, if necessary, a resin composition containing an acid-modified polyolefin (B) and other components) melted into continuous fibers drawn out at a predetermined speed and then applying heat and pressure to adjust the degree of orientation.

[0050] When the resin impregnated into the continuous fibers is a resin composition containing components other than EVOH (A), the method for producing the resin composition is not particularly limited. For example, the composition can be produced by mixing or kneading EVOH (A), an acid-modified polyolefin (B), and other components as needed under melt conditions. Mixing or kneading under melt conditions can be performed using a known mixing or kneading device, such as a Kneader-Rider, an extruder, an open roll, or a Banbury mixer. The temperature during mixing or kneading can be appropriately adjusted based on the melting point of the EVOH (A) used, and is generally within a range of 160°C to 300°C. Alternatively, the resin composition can contain other components by impregnating EVOH (A) into an aqueous solution containing other components.

[0051] A molded article comprising the fiber-reinforced EVOH sheet or tape of the present invention is also one embodiment of the present invention. The molded article may be a known molded article, preferably a pressure vessel, and particularly preferably a hydrogen tank.

[0052] The hydrogen tank can be manufactured by winding or laminating a fiber-reinforced EVOH sheet or tape around a mandrel using a winding or braiding method. Furthermore, the method preferably includes laminating a fiber-reinforced tape or sheet made of a thermoplastic resin different from EVOH onto the outside of the molded body obtained by winding or laminating the fiber-reinforced EVOH sheet or tape. The thermoplastic resin different from EVOH is not particularly limited, and examples thereof include polyamide.

[0053] Winding and braiding are well-known molding methods in which a fiber-reinforced material (filaments, rovings, or ribbons) impregnated with a matrix resin is wound around a rotating mandrel to a predetermined thickness, cured, and then demolded. The molding method is not limited to the above methods; other well-known methods include insert molding, sandwich molding, stamping, press molding, and automated lamination.

[0054] (Fiber-reinforced EVOH board) The fiber-reinforced EVOH sheet of the present invention can be manufactured by, for example, the following methods: a method of heat-molding a fabric formed by using the fiber-reinforced EVOH sheet or tape of the present invention as warp yarn, weft yarn, or both; a method of arranging the fiber-reinforced EVOH sheets or tapes of the present invention in parallel and heat-molding them; a method of alternately stacking the fiber-reinforced EVOH sheets or tapes of the present invention at 90° relative to the direction of the continuous fibers and heat-molding them, etc., but are not limited to these.

[0055] A molded article comprising the fiber-reinforced EVOH sheet of the present invention is also one embodiment of the present invention. The molded article can be produced by, for example, preheating the fiber-reinforced EVOH sheet of the present invention using an IR heater, followed by press molding using a press, but the present invention is not limited to these methods. The molded article of the present invention is preferably a hydrogen tank.

[0056] The fiber-reinforced EVOH sheets, tapes, plates, and molded articles of the present invention are suitable for applications requiring both gas barrier properties and mechanical strength. Examples include compressed natural gas tanks, liquid propane gas tanks, and hydrogen tanks. Other examples include pipes and tubes for transporting natural gas and hydrogen. The fiber-reinforced EVOH sheets, tapes, plates, and molded articles of the present invention are not limited to the applications exemplified here.

[0057] One preferred embodiment of the molded article of the present invention includes a molded article comprising the fiber-reinforced EVOH sheet or tape of the present invention and a fiber-reinforced sheet or tape containing a resin that reacts with EVOH. By stacking the fiber-reinforced EVOH sheet or tape and the fiber-reinforced sheet or tape containing a resin that reacts with EVOH and heating them above their melting temperature, they react and integrate, achieving both hydrogen barrier properties and environmental resistance. From the perspective of their reactivity, the fiber-reinforced EVOH sheet or tape and the fiber-reinforced sheet or tape containing a resin that reacts with EVOH are preferably directly in contact and stacked. From the perspective of protecting the EVOH from the external environment, a molded article preferably comprises the fiber-reinforced EVOH sheet or tape on the inside and the fiber-reinforced sheet or tape containing a resin that reacts with EVOH on the outside.

[0058] Examples of the resin that reacts with EVOH include polyamide resins, polyurethane resins, and acid-modified polyolefin resins. Among them, polyamide resins are preferred from the viewpoint of high environmental resistance.

[0059] Polyamide resins are polymers formed by polymerization of monomers via amide bonds. Specific examples of polyamide resins include polycaproamide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-ω-aminononanoic acid (nylon 9), polyundecanamide (nylon 11), polylaurolactam (nylon 12), polyethylene adipamide (nylon 26), polybutylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecanoamide (nylon 12), and polybutylene adipamide (nylon 46). Nylon 612), polyoctyl adipamide (nylon 86), polydecanediamine adipamide (nylon 106), caprolactam / laurolactam copolymer (nylon 6 / 12), caprolactam / ω-aminononanoic acid copolymer (nylon 6 / 9), caprolactam / hexamethylenediammonium adipate copolymer (nylon 6 / 66), laurolactam / hexamethylenediammonium adipate copolymer (nylon 12 / 66), ethylenediammonium adipate / hexamethylenediammonium adipate copolymer Poly(nylon 26 / 66), Poly(hexamethylenediammonium adipate / hexamethylenediammonium sebacate) copolymer (nylon 6 / 66 / 610), Poly(ethylenediammonium adipate / hexamethylenediammonium adipate / hexamethylenediammonium sebacate) copolymer (nylon 26 / 66 / 610), Poly(hexamethylene diamine isophthalamide) (nylon 6I), Poly(hexamethylene terephthalamide) (nylon 6T), Poly(hexamethylene diamine isophthalamide) Polyamide / hexamethylene terephthalamide copolymer (nylon 6I / 6T), 11-aminoundecanamide / hexamethylene terephthalamide copolymer, polynonane terephthalamide (nylon 9T), polydecane terephthalamide (nylon 10T), polyhexamethylenecyclohexamide, polynonamethylenecyclohexamide, or polyamides modified with aromatic amines such as methylenebenzylamine and meta-xylylenediamine, meta-xylylenediamine adipate, etc. Among these, at least one of nylon 11, nylon 6T, nylon 9T, and nylon 10T is preferred from the viewpoint of environmental resistance, with nylon 9T being more preferred.

[0060] Fiber-reinforced sheets or tapes of a resin reactive with EVOH can be produced by the same method as the method for producing the fiber-reinforced EVOH sheet or tape described above. Furthermore, molded articles containing fiber-reinforced sheets or tapes of a resin reactive with EVOH can be produced by the same method as the molded articles containing the fiber-reinforced EVOH sheet or tape described above. Example

[0061] The present invention will be described in more detail below using examples, etc. However, the present invention is not limited to these examples. It should be noted that while the following examples primarily describe examples using fiber-reinforced EVOH sheets, the same effects can be achieved even with tapes having a width of less than 250 mm.

[0062] [Evaluation method] (1) Orientation The fiber-reinforced EVOH sheets obtained in the Examples and Comparative Examples were measured using a 3D X-ray CT system (manufactured by Yamato Scientific) with a field of view of 2.0 mm (φ) x 2.0 mm (h), a tube voltage of 23 kV, and a tube current of 100 μA to produce 3D images. The continuous fibers in the 3D images were thinned using 3D volume imaging software (VG-StudioMAX, manufactured by Volume Graphics). The orientation ratio ((F) / (S)) was calculated for all (p) and (q) values ​​and the values ​​were number averaged.

[0063] (2) Oxygen Transmission Rate (OTR) The fiber-reinforced EVOH sheets obtained in the examples and comparative examples were humidified at 20°C / 65% RH, and then the OTR was measured using an oxygen permeability meter (OX-Tran 2 / 20 manufactured by Modern Control) at 20°C / 65% RH. The thickness of the obtained OTR was calculated as follows: OTR ÷ thickness (μm) × 20 (cc・20μm / (m 2 ・day・atm))).

[0064] (3) Hydrogen permeation rate (H2TR) The fiber-reinforced EVOH sheets obtained in the examples and comparative examples were humidified at 20°C / 0% RH and then measured for H2TR using a GTR-21 manufactured by GTR TEC Co., Ltd. at 20°C / 0% RH in accordance with ISO 15105-1 (GC method). The thickness of the obtained H2TR was calculated as follows: H2TR ÷ thickness (μm) × 20 (cc・20μm / (m 2 ・day・atm))).

[0065] (4) Fiber content Approximately 350 mg of the fiber-reinforced EVOH sheets obtained in the Examples and Comparative Examples were sampled and weighed, with this weight being designated M1. Next, 15 mL of HFIP (1,1,1,3,3,3-hexafluoro-2-propanol) was added and allowed to stand at room temperature for one day to dissolve the EVOH and produce continuous fibers. The resulting continuous fibers were then filtered and vacuum-dried at room temperature and weighed, with this weight being designated M2. The fiber content was calculated using the following formula.

[0066] Fiber content = (M2 / M1) × 100 (%) (5) Bending strength The fiber-reinforced ethylene-vinyl alcohol copolymer plates obtained in Examples and Comparative Examples were measured at 23° C. and 50% RH in accordance with ISO 14125. When the flexural strength was 1400 MPa or less, the strength was determined to be insufficient.

[0067] [Materials used] EVOH 1: "EVAL (registered trademark) L171B" (EVOH, manufactured by Kuraray Co., Ltd., ethylene unit content 27 mol%, saponification degree 99.9 mol%, 4.0 g / 10min MFR (210°C, 2160 g load)) EVOH2: "EVAL (registered trademark) F101B" (EVOH, manufactured by Kuraray Co., Ltd., ethylene unit content 32 mol%, saponification degree 99.9 mol%, 3.8 g / 10min MFR (210°C, 2160 g load)) Acid-modified PO1: "Tafmer (trademark) MH7020" (maleic anhydride-modified ethylene-1-butene copolymer, manufactured by Mitsui Chemicals, Inc.) ・PA6: "AMILAN (trademark) CM3001N" (nylon 6, manufactured by Toray Industries, Ltd., melting point 265°C) Carbon fiber 1: T700S (carbon fiber, manufactured by Toray Industries, Inc., density 1.8, diameter 7μm, filament count 12,000) (Example 1) Carbon fiber 1, opened at 120°C and widened to 30 cm in width, was pulled at 2 m / min. EVOH 1 melted at 220°C was evenly draped over the continuous fibers, with the mass ratio of EVOH 1 to continuous fibers being approximately 1:1. This was sandwiched between polyimide films and pressed using a roll press at 220°C and 2 MPa, followed by cooling to obtain a fiber-reinforced EVOH sheet with a width of 30 cm and a thickness of 0.21 mm. The resulting fiber-reinforced EVOH sheet was measured for orientation, OTR, and H2TR according to the evaluation methods (1) to (3) above. The results are shown in Table 1.

[0068] Twelve sheets of the obtained fiber-reinforced EVOH sheets were stacked in a pattern of 0°, 90°, 0°, 90°, 0°, 90°, 0°, 90°, 0°, 90°, 0°, and 0°, and placed in a 12 cm square mold. The mold was placed in a vacuum press, and the mold temperature was raised from 30°C to 220°C over 40 minutes while evacuating the mold. After maintaining the temperature at 220°C for 30 minutes, the vacuum was stopped, and the mold was cooled to 30°C over 15 minutes while applying a pressure of 5 MPa, resulting in a fiber-reinforced EVOH board with a thickness of approximately 2 mm. The fiber content and flexural strength of the obtained fiber-reinforced EVOH board were measured according to the methods described in the above-mentioned evaluation methods (4) and (5). The results are shown in Table 1.

[0069] (Example 2) 90 parts by mass of EVOH1, 10 parts by mass of acid-modified PO1, and an antioxidant (0.25 parts by mass of pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] ("IRGANOX 1010" manufactured by BASF) and 0.25 parts by mass of N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide] ("IRGANOX 1098" manufactured by BASF)) were dry-blended and extruded using a 30 mmφ twin-screw extruder ("TEX-30SS-30CRW-2V" manufactured by Nippon Steel Works, Ltd.) at 220°C, a screw speed of 200 rpm, and an extruded resin amount of 25 kg / hour to form pellets. The mixture was then dried at 30°C under reduced pressure for 16 hours to obtain resin composition pellets. A fiber-reinforced EVOH sheet and a fiber-reinforced EVOH board were prepared and evaluated in the same manner as in Example 1, except that the obtained resin composition pellets were used instead of EVOH 1. The results are shown in Table 1.

[0070] (Example 3) A fiber-reinforced EVOH sheet and a fiber-reinforced EVOH board were produced and evaluated in the same manner as in Example 1 except that EVOH 2 was used instead of EVOH 1. The results are shown in Table 1.

[0071] (Comparative Example 1) Carbon fibers were aligned in the same direction on a 100 μm thick EVOH2 film, which was then supported on top of the film. The film-to-carbon fiber mass ratio was set to approximately 1:1. Pressing was performed using a press at 220°C and 2 MPa to produce a 0.78 mm thick fiber-reinforced EVOH sheet. The resulting fiber-reinforced EVOH sheet was then measured for orientation, OTR, and H2TR according to the evaluation methods (1) to (3) above. The results are shown in Table 1.

[0072] Six sheets of the resulting fiber-reinforced EVOH sheets were stacked in a pattern with the fiber orientations at 0°, 90°, 0°, 0°, 90°, and 0°, and then placed in a 12 cm square mold. The mold was placed in a vacuum press, and the mold temperature was raised from 30°C to 220°C over 40 minutes while evacuating the mold. After maintaining the temperature at 220°C for 30 minutes, the vacuum was stopped, and the mold was cooled to 30°C over 15 minutes while applying a pressure of 5 MPa, resulting in a fiber-reinforced EVOH sheet with a thickness of approximately 2 mm. The fiber content and flexural strength of the resulting fiber-reinforced EVOH sheet were measured according to the methods described in the above-mentioned evaluation methods (4) and (5). The results are shown in Table 1.

[0073] (Comparative Example 2) A fiber-reinforced sheet and a fiber-reinforced plate were produced and evaluated in the same manner as in Example 1 except that PA6 was used instead of EVOH1 and the temperature setting was changed from 220°C to 280°C. The results are shown in Table 1. .

Claims

1. A fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape comprising an ethylene-vinyl alcohol copolymer (A) and continuous fibers, wherein the continuous fibers are oriented in the MD direction so that the average orientation degree determined by the following formula (1) is 2 or less. Orientation degree = (F) / (S) (1) In formula (1), (F) refers to the path length of the shortest path from (p) to (q) via only continuous fibers, when any intersection point between one of the two sides in the TD direction and the continuous fibers is defined as intersection point (p), and any intersection point between the other side in the TD direction that can be reached from (p) via only continuous fibers and the continuous fibers is defined as intersection point (q), in a square area obtained by cutting the fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape by 2 mm in the TD direction and by 2 mm in the MD direction; (S) is the straight-line distance between (p) and (q); in, If the continuous fibers intersect with each other when observing the square area from the thickness direction of the fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape, the continuous fibers are actually separated from each other in the thickness direction, and even when they are not in contact, the continuous fibers are considered to constitute a continuous path.

2. The fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape according to claim 1, wherein: The continuous fiber is at least one selected from the group consisting of carbon fiber, glass fiber, aramid fiber, wholly aromatic polyester fiber, ceramic fiber and metal fiber.

3. The fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape according to claim 1, wherein The ethylene unit content of the ethylene-vinyl alcohol polymer (A) is 15 mol% or more and 50 mol% or less.

4. The fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape according to claim 1, wherein The content of the ethylene-vinyl alcohol copolymer (A) is 20% by mass or more and 80% by mass or less, and the content of the continuous fibers is 20% by mass or more and 80% by mass or less. 5 . The fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape according to claim 1 , further comprising an acid-modified polyolefin (B).

6. A molded article comprising the fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape according to any one of claims 1 to 5. The molded article according to claim 6 , which is a pressure container. The molded article according to claim 7 , which is a hydrogen tank.

9. The method for producing a molded article according to claim 8, comprising: The process of winding or laminating a fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape on a core rod using a winding molding method or a braid molding method.

10. The manufacturing method according to claim 9, comprising: A step of winding or laminating a fiber-reinforced sheet or tape made of a thermoplastic resin different from the ethylene-vinyl alcohol copolymer around the outside of a molded article comprising a fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape.

11. A fiber-reinforced ethylene-vinyl alcohol copolymer plate comprising the fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape according to any one of claims 1 to 5.

12. A molded article comprising the fiber-reinforced ethylene-vinyl alcohol copolymer sheet according to claim 11. The molded article according to claim 12 , which is a hydrogen tank.

14. A molded article comprising the fiber-reinforced ethylene-vinyl alcohol copolymer sheet or tape according to any one of claims 1 to 5, and a fiber-reinforced sheet or tape containing a resin reactive with the ethylene-vinyl alcohol copolymer.

15. The molded article according to claim 14, wherein The resin that reacts with the ethylene-vinyl alcohol copolymer is a polyamide resin.

Images