Resin composition, multilayer structure, molded article, and method for producing resin composition

Abstract

As a resin composition having excellent thermal stability, a resin composition containing an ethylene-vinyl alcohol copolymer (A) and lycopene (B) is provided.

Description

Technical Field

[0001] The present invention relates to a resin composition, and more particularly, to a resin composition having improved thermal stability. Background Art

[0002] Ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as "EVOH") has very strong intermolecular forces due to hydrogen bonds between hydroxyl groups existing in the polymer side chains. Therefore, the crystallinity is high, and the intermolecular forces are also high in the amorphous part. Therefore, the film using EVOH is not easy to pass gas molecules, etc., and has excellent gas barrier properties.

[0003] Resin compositions containing EVOH are excellent in transparency, gas barrier properties such as oxygen, aroma retention, solvent resistance, oil resistance, mechanical strength, etc. Therefore, they are molded into films, sheets, bottles, etc. and widely used as various packaging materials such as food packaging materials, drug packaging materials, industrial drug packaging materials, and pesticide packaging materials. For example, Patent Document 1 discloses a multilayer structure having an EVOH layer.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-234805 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] As mentioned above, EVOH is widely used as various packaging materials, but there is room for improvement in thermal stability.

[0009] Solutions for solving problems

[0010] The present inventors have conducted intensive studies in view of the above circumstances and have found that a resin composition having excellent thermal stability can be obtained by combining EVOH and lycopene.

[0011] That is, the present invention provides the following [1] to [6].

[0012] [1] A resin composition comprising EVOH (A) and lycopene (B).

[0013] [2] The resin composition according to [1], wherein the content of the lycopene (B) is 0.001 to 100 ppm based on the resin composition.

[0014] [3] The resin composition according to [1] or [2], further comprising a polyolefin-based resin (C).

[0015] [4] A multilayer structure having a layer comprising the resin composition according to any one of [1] to [3].

[0016] [5] A molded article formed from the resin composition according to any one of [1] to [3].

[0017] [6] A method for producing a resin composition, which is a method for producing the resin composition described in any one of [1] to [3], the method comprising the following steps:

[0018] The ethylene-vinyl alcohol copolymer (A) and lycopene (B) are mixed.

[0019] Effects of the Invention

[0020] The resin composition of the present invention has excellent thermal stability. In addition, a multilayer structure having a layer containing the resin composition of the present invention and a molded body formed from the resin composition of the present invention also have excellent thermal stability. DETAILED DESCRIPTION

[0021] The present invention will be described in detail below, but these are merely examples of preferred embodiments.

[0022] In the present invention, when expressed as "X to Y" (X and Y are arbitrary numbers), unless otherwise specified, it includes the meaning of "X or more and Y or less", as well as the meaning of "preferably greater than X" or "preferably less than Y".

[0023] Furthermore, when expressed as "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number), it also includes the meaning of "preferably greater than X" or "preferably less than Y".

[0024] Furthermore, "x and / or y (x, y are arbitrary structures or components)" means three combinations of only x, only y, and x and y.

[0025] A resin composition as one embodiment of the present invention (hereinafter referred to as “the present resin composition”) contains EVOH (A) and lycopene (B).

[0026] Hereinafter, each component will be described.

[0027] [EVOH(A)]

[0028] EVOH (A) used in the present resin composition is generally a resin obtained by saponifying an ethylene-vinyl ester copolymer, which is a copolymer of ethylene and a vinyl ester monomer, and is a water-insoluble thermoplastic resin. As the vinyl ester monomer, vinyl acetate is generally used for economical reasons.

[0029] As the copolymerization method of ethylene and vinyl ester monomers, any known polymerization method such as solution polymerization, suspension polymerization, emulsion polymerization, etc. can be used, and solution polymerization using methanol as a solvent is usually used. The saponification of the obtained ethylene-vinyl ester copolymer can also be carried out by a known method.

[0030] The EVOH (A) produced in this way mainly contains ethylene structural units and vinyl alcohol structural units, and contains a trace amount of vinyl ester structural units remaining as unsaponified portions when the saponification degree is less than 100 mol %.

[0031] As the aforementioned vinyl ester monomer, vinyl acetate is generally used as described above from the perspective of economic efficiency and the efficiency of treating impurities during production. In addition, as vinyl ester monomers other than vinyl acetate, for example, aliphatic vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, and vinyl versatate, and aromatic vinyl esters such as vinyl benzoate can be cited. These can be used alone or in combination of two or more. Among them, aliphatic vinyl esters having 3 to 20 carbon atoms are preferred, 4 to 10 carbon atoms are more preferred, and 4 to 7 carbon atoms are particularly preferred.

[0032] The content of ethylene structural units in the EVOH (A) measured based on ISO14663 is usually 20 to 60 mol%, preferably 25 to 50 mol%, and particularly preferably 27 to 35 mol%. When the above content is too low, there is a tendency for the gas barrier properties and melt moldability under high humidity to decrease, and conversely, when it is too high, there is a tendency for the gas barrier properties to decrease. It should be noted that the content of the above ethylene structural units can be controlled by the pressure of ethylene when copolymerizing the vinyl ester monomer with ethylene.

[0033] The saponification degree of the EVOH (A) measured in accordance with JIS K6726 (wherein the EVOH (A) is uniformly dissolved in a water / methanol solvent) is usually 90 to 100 mol%, preferably 95 to 100 mol%, and particularly preferably 99 to 100 mol%. When the saponification degree is too low, the gas barrier properties tend to be reduced. It should be noted that the saponification degree can be controlled by the amount of the saponification catalyst (usually a basic catalyst such as sodium hydroxide is used) when saponifying the ethylene-vinyl ester copolymer, the temperature, the time, etc.

[0034] The melt flow rate (MFR) (210°C, load 2160 g) of the EVOH (A) is usually 0.1 to 100 g / 10 min, preferably 1 to 50 g / 10 min, and particularly preferably 3 to 35 g / 10 min. If the MFR is too large, the film forming properties tend to become unstable, while if it is too small, the viscosity tends to become excessively high, making melt extrusion difficult.

[0035] The MFR is an index of the degree of polymerization of EVOH (A), and can be adjusted by the amount of the polymerization initiator and the amount of the solvent when ethylene and the vinyl ester monomer are copolymerized.

[0036] EVOH (A) may further contain a structural unit derived from the following comonomer within a range not impairing the effects of the present invention (for example, 10 mol % or less of EVOH (A)).

[0037] Examples of the comonomer include olefins such as propylene, 1-butene, and isobutylene; hydroxyl-containing α-olefins such as 3-butene-1-ol, 3-butene-1,2-diol, 4-pentene-1-ol, and 5-hexene-1,2-diol, and their derivatives such as esters and acylates; hydroxyalkyl vinylides such as 2-methylenepropane-1,3-diol and 3-methylenepentane-1,5-diol; 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy- Hydroxyalkyl vinylene diacetates such as 2-methylenepropane and 1,3-dibutyryloxy-2-methylenepropane; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, phthalic acid (anhydride), maleic acid (anhydride), itaconic acid (anhydride) or their salts or mono- or di-alkyl esters with an alkyl group having 1 to 18 carbon atoms; acrylamide, N-alkyl acrylamide with an alkyl group having 1 to 18 carbon atoms, N,N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or its salts, acrylamidopropyl dimethyl acrylamides such as methyl methacrylamide, N-alkyl methacrylamide with an alkyl carbon number of 1 to 18, N,N-dimethyl methacrylamide, 2-methyl acrylamide propanesulfonic acid or its salt, methyl acrylamide propyl dimethylamine or its acid salt or its quaternary salt; N-vinyl amides such as N-vinyl pyrrolidone, N-vinyl formamide, N-vinyl acetamide; vinyl cyanides such as acrylonitrile and methacrylonitrile; alkyl Vinyl ethers such as alkyl vinyl ethers, hydroxyalkyl vinyl ethers, and alkoxyalkyl vinyl ethers having 1 to 18 carbon atoms; halogenated vinyl compounds such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and vinyl bromide; vinyl silanes such as trimethoxyvinylsilane; halogenated allyl compounds such as allyl acetate and allyl chloride; allyl alcohols such as allyl alcohol and dimethoxyallyl alcohol; trimethyl-(3-acrylamide-3-dimethylpropyl)-ammonium chloride, acrylamide-2-methylpropanesulfonic acid, etc. These may be used alone or in combination of two or more.

[0038] EVOH copolymerized with hydroxyl-containing α-olefins, that is, EVOH having hydroxyl groups in the side chains is particularly preferred in terms of improving secondary moldability while maintaining gas barrier properties. EVOH having primary hydroxyl groups in the side chains is more preferred, and EVOH having a 1,2-diol structure in the side chains is particularly preferred.

[0039] In the EVOH having a primary hydroxyl group in the side chain, the content of the structural unit derived from the monomer having the primary hydroxyl group is preferably usually 0.1 to 20 mol %, further preferably 0.5 to 15 mol %, particularly preferably 1 to 10 mol % of the EVOH.

[0040] The EVOH (A) may be one that has been “post-modified” by urethanization, acetaldehyde condensation, cyanoethylation, oxyalkyleneation or the like.

[0041] Furthermore, the EVOH (A) used in the present resin composition may be a mixture of two or more types of EVOH, for example, EVOHs having different degrees of saponification, different degrees of polymerization, different copolymerization components, and the like.

[0042] The content of EVOH (A) in the present resin composition is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 10% by mass or more, particularly preferably 50% by mass or more, and most preferably 80% by mass or more. It should be noted that the upper limit of the content of EVOH (A) is the total mass of the resin composition minus lycopene (B). When the above value is within the above range, there is a tendency to more effectively obtain the effect of the present invention.

[0043] [Lycopene (B)]

[0044] Lycopene (B) used in the present resin composition is a type of carotene. The present resin composition improves thermal stability by containing lycopene (B).

[0045] The content of lycopene (B) is not particularly limited, but is preferably 0.001 to 100 ppm, more preferably 0.005 to 90 ppm, further preferably 0.01 to 50 ppm, particularly preferably 0.05 to 10 ppm, and most preferably 0.1 to 1 ppm relative to the resin composition. The above-mentioned content of lycopene (B) can further improve the coloring resistance after heating.

[0046] [Polyolefin resin (C)]

[0047] The present resin composition preferably contains a polyolefin-based resin (C) as an optional component.

[0048] Examples of the polyolefin resin (C) include polypropylene; propylene resins such as propylene copolymers of propylene with α-olefins such as ethylene, 1-butene, 1-hexene, and 4-methyl-1-pentene; polyethylenes such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene; ethylene resins such as ethylene copolymers of ethylene with α-olefins such as 1-butene, 1-hexene, and 4-methyl-1-pentene; poly(1-butene), poly(4-methyl-1-pentene), and the like.

[0049] The polyolefin-based resin (C) may be used alone or as a mixture of two or more types having different copolymerization component compositions, physical properties, etc.

[0050] Among them, as the polyolefin resin (C), propylene resins such as polypropylene and propylene copolymers, and ethylene resins such as polyethylene and ethylene copolymers are preferred. From the viewpoint of obtaining a molded body with excellent heat resistance, as the polyolefin resin (C), propylene resins are preferred, and polypropylene is more preferred. On the other hand, from the viewpoint of obtaining a molded body with excellent transparency, as the polyolefin resin (C), ethylene resins are preferred, polyethylene is more preferred, and linear low-density polyethylene is further preferred.

[0051] The melt flow rate (MFR: 190°C or 210°C, load 2160 g) of the polyolefin resin (C) is not particularly limited, but is usually 0.01 to 150 g / 10 min, preferably 0.1 to 50 g / 10 min, more preferably 0.5 to 25 g / 10 min, further preferably 0.8 to 10 g / 10 min.

[0052] The content of the polyolefin resin (C) in the present resin composition is not particularly limited, and is generally 0.1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 50% by mass or more, particularly preferably 80% by mass or more, and most preferably 90% by mass or more. It should be noted that the upper limit of the content of the polyolefin resin (C) is generally 99.99% by mass.

[0053] The total content of EVOH (A) and polyolefin resin (C) in the present resin composition is not particularly limited, but is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more. It should be noted that the upper limit of the total content of EVOH (A) and polyolefin resin (C) is the total mass of the resin composition minus the mass of lycopene (B).

[0054] In the present resin composition, the mass content ratio of EVOH (A) to the polyolefin resin (C) [EVOH (A) / polyolefin resin (C)] is usually 0.1 / 99.9 to 99.9 / 0.1, preferably 1 / 99 to 99 / 1, more preferably 2 / 98 to 98 / 2, further preferably 3 / 97 to 90 / 10, particularly preferably 4 / 96 to 80 / 20, and most preferably 5 / 95 to 50 / 50. When the mass content ratio of EVOH (A) to the polyolefin resin (C) is within the above range, the effect of the present invention tends to be more effectively obtained.

[0055] [Other ingredients]

[0056] In the present resin composition, in the range that does not significantly impair the effects of the present invention, resins other than EVOH (A), polyolefin resin (C) and arbitrary additives other than lycopene (B) (hereinafter referred to as "other components") may be blended according to various purposes. Other components may be used alone or in any combination and ratio.

[0057] As examples of other components, plasticizers, reinforcing agents, fillers, pigments, dyes, lubricants, antioxidants, antistatic agents, ultraviolet absorbers, heat stabilizers, light stabilizers, surfactants, antibacterial agents, antistatic agents, desiccants, antiblocking agents, flame retardants, crosslinking agents, curing agents, foaming agents, crystal nucleating agents, etc. can be enumerated. The content of other components in this resin composition is generally 50% by mass or less in total, preferably 20% by mass or less, and more preferably 10% by mass or less.

[0058] [Method for producing resin composition]

[0059] The present resin composition is produced using the aforementioned essential components EVOH (A) and lycopene (B), and, if necessary, the polyolefin-based resin (C) and the aforementioned other components.

[0060] The present resin composition only needs to contain EVOH (A) and lycopene (B), and for example, may include a step of mixing EVOH (A) and lycopene (B). However, the method of mixing EVOH (A) and lycopene (B) is not particularly limited.

[0061] Examples of the method for producing the present resin composition include known methods such as dry blending, melt mixing, solution mixing, and impregnation, and these methods may be arbitrarily combined.

[0062] As the above-mentioned mixing method, there is no particular limitation, and the components can also be mixed by dry blending and directly utilized as a resin composition. However, what is usually used is to mix by melt mixing, solution mixing, etc., and then molded into a shape that is easy to handle such as pellets. As a method for preparing a resin composition, a melt mixing method is preferred for productivity.

[0063] As the above-mentioned melt mixing method, the method of melting and mixing after dry blending each component can be enumerated usually. As a mixing device, for example, known mixing devices such as kneader, extruder, grinding roller, Banbury mixer, PLASTOMILL can be used, and it is usually preferred to use a single screw or twin screw extruder in industry. In addition, the aforementioned extruder is also preferably provided with a vent filter device, a gear pump device, a wire mesh device, etc. as required.

[0064] The melt kneading temperature is usually set as the extruder and die temperature in the range of 160 to 300° C., preferably 170 to 260° C., and particularly preferably 180 to 240° C. If the temperature is too low, the resin is in an unmelted state and the processing state tends to become unstable. If the temperature is too high, the resin composition is thermally degraded and the quality of the obtained molded article tends to decrease.

[0065] The method for adjusting the amount of lycopene (B) and any other components in the resin composition is not particularly limited, and may be a method of adding a desired amount and adjusting, a method of preparing a masterbatch and diluting, etc. In the case of diluting the masterbatch, any method may be used for dilution, but dry blending is preferred for productivity.

[0066] The present resin composition obtained in this manner can be suitably used as a multilayer structure or a molded product.

[0067] [Multilayer structure]

[0068] The multilayer structure as one embodiment of the present invention (hereinafter referred to as “the present multilayer structure”) has at least one layer containing the present resin composition (hereinafter referred to as “resin composition layer”).

[0069] The present multilayer structure only needs to have the above-mentioned resin composition layer, and there is no particular limitation on the composition of other layers. For example, it may have a substrate layer comprising paper, nonwoven fabric, metal foil, or other substrates (hereinafter referred to as "substrate resins") having a thermoplastic resin other than the present resin composition as the main component.

[0070] Examples of the base resin include linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, polyethylene resins such as ethylene-propylene (block and random) copolymers and ethylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymers, polypropylene resins such as polypropylene and propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymers, (unmodified) polyolefin resins such as polybutene, polypentene, and polycycloolefin resins (polymers having a cycloolefin structure in at least one of the main chain and the side chain), and polyolefin resins such as these. The invention also includes polyolefin resins in a broad sense such as unsaturated carboxylic acid-modified polyolefin resins graft-modified with unsaturated carboxylic acid or its ester, ionomers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers, polyester resins, polyamide resins (including copolymerized polyamides), polyvinyl chloride, polyvinylidene chloride, acrylic resins, polystyrene resins, vinyl ester resins, polyester elastomers, polyurethane elastomers, polystyrene elastomers, chlorinated polyethylene, chlorinated polypropylene and other halogenated polyolefins, aromatic or aliphatic polyketones, etc. These can be used alone or in combination of two or more.

[0071] Among these, preferred are polyamide resins, polyolefin resins, polyester resins, and polystyrene resins, which are hydrophobic resins; more preferred are polyolefin resins such as polyethylene resins, polypropylene resins, polycycloolefin resins, and unsaturated carboxylic acid-modified polyolefin resins thereof; and it is particularly preferred to use polycycloolefin resins as the hydrophobic resin.

[0072] The layer structure of the present multilayer structure, when the resin composition layer is set to a (a1, a2, ...) and the substrate resin layer is set to b (b1, b2, ...), can be any combination of a / b, b / a / b, a / b / a, a1 / a2 / b, a / b1 / b2, b2 / b1 / a / b1 / b2, b2 / b1 / a / b1 / a / b1 / b2, etc. In addition, when the end portion, defective product generated in the process of manufacturing the present multilayer structure, or the recycled layer containing the mixture of the present resin composition and the substrate resin obtained by remelting and molding the manufactured multilayer structure is set to R, it can also be formed into b / R / a, b / R / a / b, b / R / a / R / b, b / a / R / a / b, b / R / a / R / a / R / b, etc. The number of layers of the present multilayer structure is generally 2 to 15, preferably 3 to 10 in total. In the above-mentioned layer structure, an adhesive resin layer containing an adhesive resin may be interposed between the layers as necessary.

[0073] As the above-mentioned adhesive resin, known ones can be used, and they can be appropriately selected according to the type of thermoplastic resin used in the substrate resin layer "b". Representative examples include: modified polyolefin polymers containing carboxyl groups obtained by chemically bonding unsaturated carboxylic acids or their anhydrides to polyolefin resins through addition reactions, grafting reactions, etc. For example, maleic anhydride grafted modified polyethylene, maleic anhydride grafted modified polypropylene, maleic anhydride grafted modified ethylene-propylene (block and random) copolymers, maleic anhydride grafted modified ethylene-ethyl acrylate copolymers, maleic anhydride grafted modified ethylene-vinyl acetate copolymers, maleic anhydride modified polycycloolefin resins, maleic anhydride grafted modified polyolefin resins, etc. In addition, a mixture of one or more of these can be used.

[0074] In the present multilayer structure, when an adhesive resin layer is used between the resin composition layer and the base material layer, the adhesive resin layer is located in contact with the resin composition layer, and therefore, an adhesive resin having excellent hydrophobicity is preferably used.

[0075] The above-mentioned base resin and adhesive resin may contain conventionally known plasticizers, fillers, clay (montmorillonite, etc.), colorants, antioxidants, antistatic agents, lubricants, nucleating agents, antiblocking agents, waxes, etc., within the range that does not hinder the gist of the present invention (for example, usually 30% by mass or less, preferably 10% by mass or less relative to the base resin and adhesive resin). These may be used alone or in combination of two or more.

[0076] The lamination of the present resin composition and the above-mentioned substrate resin (including the case of sandwiching an adhesive resin layer) can be carried out by a known method. For example, the following methods can be cited: a method of melt-extrusion laminating the substrate resin on a film, sheet, etc. of the present resin composition; a method of melt-extrusion laminating the present resin composition on a substrate resin layer; a method of co-extruding the present resin composition and the substrate resin; a method of dry laminating the resin composition layer and the substrate resin layer using a known adhesive such as an organic titanium compound, an isocyanate compound, a polyester compound, a polyurethane compound, etc.; a method of removing the solvent after applying a solution of the present resin composition on the substrate resin; etc. Among them, from the perspective of cost and environment, the co-extrusion method is preferred.

[0077] The multilayer structure is subjected to (heating) stretching treatment as required. The stretching treatment may be uniaxial stretching or biaxial stretching. In the case of biaxial stretching, it may be simultaneous stretching or sequential stretching. In addition, as a stretching method, a method with a high stretching ratio such as a roller stretching method, a tenter stretching method, a tubular stretching method, a stretch blow molding method, and a vacuum pressure forming method may also be adopted. The stretching temperature is selected from a range of usually 40 to 170°C, preferably about 60 to 160°C, at a temperature near the melting point of the multilayer structure. When the stretching temperature is too low, there is a tendency for the stretchability to become poor, and when it is too high, there is a tendency for it to be difficult to maintain a stable stretched state.

[0078] The thickness of the present multilayer structure (including the stretched one), the thickness of the resin composition layer, the base resin layer and the adhesive resin layer further constituting the present multilayer structure cannot be generalized depending on the layer constitution, the type of base resin, the type of adhesive resin, the application, the packaging form, the required physical properties, etc., but the thickness of the present multilayer structure (including the stretched one) is usually 10 to 5000 μm, preferably 30 to 3000 μm, and particularly preferably 50 to 2000 μm. The resin composition layer is usually 1 to 500 μm, preferably 3 to 300 μm, and particularly preferably 5 to 200 μm, the base resin layer is usually 5 to 3000 μm, preferably 10 to 2000 μm, and particularly preferably 20 to 1000 μm, and the adhesive resin layer is usually 0.5 to 250 μm, preferably 1 to 150 μm, and particularly preferably 3 to 100 μm.

[0079] Furthermore, for the thickness ratio of the resin composition layer to the substrate resin layer in the present multilayer structure (resin composition layer / substrate resin layer), when each layer has multiple layers, the ratio of the thickest layers is usually 1 / 99 to 50 / 50, preferably 5 / 95 to 45 / 55, and particularly preferably 10 / 90 to 40 / 60. In addition, for the thickness ratio of the resin composition layer to the adhesive resin layer in the present multilayer structure (resin composition layer / adhesive resin layer), when each layer has multiple layers, the ratio of the thickest layers is usually 10 / 90 to 99 / 1, preferably 20 / 80 to 95 / 5, and particularly preferably 50 / 50 to 90 / 10.

[0080] It should be noted that, after stretching, heat setting may be performed in order to impart dimensional stability. Heat setting may be performed by known means, for example, while the stretched film is kept in a tensioned state, heat treatment is performed at 80 to 180° C., preferably 100 to 165° C., for about 2 to 600 seconds. In addition, when the multilayer stretched film obtained from the present resin composition is used as a shrink film, in order to impart heat shrinkage, for example, cold air may be blown to the stretched film and cooled and fixed without performing the above-mentioned heat setting.

[0081] In addition, the present multilayer structure can also be used to obtain a cup or tray-shaped multilayer container. In this case, a deep drawing method is usually used, and specific examples include vacuum forming, pressure forming, vacuum pressure forming, and plug-assisted vacuum pressure forming. In the case of obtaining a tube or bottle-shaped multilayer container (laminated structure) from a multilayer parison (a hollow tubular preform before blow molding), a blow molding method is used. Specifically, examples include extrusion blow molding (double-head type, mold moving type, parison displacement type, rotary type, accumulator type, horizontal parison type, etc.), frozen parison blow molding, injection blow molding, biaxial stretch blow molding (extrusion frozen parison biaxial stretch blow molding, injection frozen parison biaxial stretch blow molding, injection molding online biaxial stretch blow molding, etc.). The obtained laminate can be subjected to heat treatment, cooling treatment, calendaring treatment, printing treatment, dry lamination treatment, solution or melt coating treatment, bag making processing, deep drawing processing, box processing, tubular processing, splitting processing, etc. as needed.

[0082] [Molding body]

[0083] A molded article (hereinafter referred to as "the present molded article") as one embodiment of the present invention is obtained by molding the present resin composition.

[0084] Examples of the shape of the molded article include films, sheets, tapes, cups, trays, tubes, bottles, pipes, filaments, extrudates with irregular cross sections, and various amorphous molded products.

[0085] The molding method of the present molded article is not particularly limited, and any molding method that can be applied to a general resin composition can be applied, and a melt molding method is generally used.

[0086] Examples of the melt molding method include extrusion molding (T-die extrusion, inflation extrusion, blow molding, melt spinning, profile extrusion, etc.) and injection molding.

[0087] The melt molding temperature can be appropriately selected usually from the range of 150 to 300°C.

[0088] In further molding, in order to improve the physical properties of the molded body or to mold it into any desired container shape, a heat stretching treatment may also be implemented. The heat stretching treatment here refers to the operation of uniformly molding a film, sheet, or parison-shaped molded product that has been uniformly heated in a thermal manner into a cup, tray, tube, bottle, or film-shaped product using a chuck, a mold plug, a vacuum force, a compressed air force, a blow molding, or the like. Moreover, as the stretching method, roller stretching, tenter stretching, tubular stretching, stretch blow molding, vacuum molding, compressed air molding, vacuum compressed air molding, and the like can be cited. Stretching can be either uniaxial stretching or biaxial stretching. In the case of biaxial stretching, any method of simultaneous biaxial stretching or sequential biaxial stretching can be adopted. The stretching temperature is usually 60 to 170°C, and more preferably 80 to 160°C.

[0089] The resin composition, the molded article and the multilayer structure are particularly useful as various packaging material containers for common foods, condiments such as mayonnaise and salad dressing, fermented foods such as mayonnaise, oily foods such as salad oil, beverages, cosmetics, and pharmaceuticals.

[0090] Example

[0091] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist of the invention is exceeded.

[0092] It should be noted that, in the examples, "parts" refer to mass standards.

[0093] Prior to the examples, the following ingredients were prepared.

[0094] EVOH (A1): ethylene structural unit content 32 mol%, MFR 3 g / 10 min (210°C, load 2160 g), saponification degree 99.7 mol%

[0095] EVOH (A2): ethylene structural unit content 44 mol%, MFR 3 g / 10 min (210°C, load 2160 g), saponification degree 99.6 mol%

[0096] Lycopene (B): manufactured by Tokyo Chemical Industry Co., Ltd.

[0097] β-Carotene (B'): manufactured by Tokyo Chemical Industry Co., Ltd.

[0098] Polyethylene (C): "NOVATEC (registered trademark) UF421 (linear low-density polyethylene)" manufactured by Japan Polyethylene Corporation, MFR 0.9 g / 10 min (190° C., load 2160 g)

[0099] <Example 1>

[0100] (Manufacturing of Masterbatch 1)

[0101] 150 mg of lycopene (B) was added to 3 mL of a mixed solution of tetrahydrofuran: ethanol = "3:2 (volume ratio)", and a slurry was obtained using an ultrasonic vibration device. The obtained slurry was dry-mixed in 1.5 kg of EVOH (A1), and dried in a vacuum dryer at 40°C for 2 hours under a vacuum state to obtain a mixture 1. The mixture 1 was supplied to a twin-screw extruder with a double-hole die (manufactured by Imoto machinery Co., Ltd., 20 mmΦ, L / D = 25), and the discharged strands were air-cooled and solidified. Next, air was blown into the strands to remove water droplets on the surface of the strands, and then the strands were cut to produce pellets of the masterbatch 1. The extrusion conditions were set as follows.

[0102] Extruder set temperature: C1 / C2 / C3 / C4=170 / 210 / 210 / 210℃

[0103] The masterbatch 1 and EVOH (A1) were dry-mixed at a ratio of 99.9:0.1 mass %, and the mixture was supplied to a twin-screw extruder with a double-hole die (manufactured by Imoto machinery Co., Ltd., 20 mm Φ, L / D = 25), and the discharged strands were air-cooled and solidified. Next, air was blown to the strands to remove water droplets on the surface of the strands, and then the strands were cut to prepare the resin composition (pellets) of Example 1. The extrusion conditions were set as follows.

[0104] Extruder set temperature: C1 / C2 / C3 / C4=170 / 210 / 210 / 210℃

[0105] <Examples 2 to 5>

[0106] A resin composition was prepared in the same manner as in Example 1 except that the type of EVOH and the content of lycopene were changed as described in Table 1 below.

[0107] <Example 6>

[0108] (Manufacturing of Masterbatch 2)

[0109] 0.9 kg of polyethylene (C) and 0.1 kg of EVOH (A1) were dry-mixed to obtain a dry-mixed product. 100 mg of lycopene (B) was added to 3 mL of a mixed solution of tetrahydrofuran: ethanol = "3:2 (volume ratio)", and a slurry was obtained using an ultrasonic vibration device. The obtained slurry was dry-mixed into the dry-mixed product, and dried in a vacuum dryer at 40°C for 2 hours under a vacuum state to obtain a mixture 2. The mixture 2 was supplied to a twin-screw extruder with a double-hole die (manufactured by Imoto machinery Co., Ltd., 20 mmΦ, L / D = 25), and the discharged strands were air-cooled and solidified. Next, air was blown into the strands to remove water droplets on the surface of the strands, and then the strands were cut to produce pellets of the masterbatch 2. The extrusion conditions were set as follows.

[0110] Extruder set temperature: C1 / C2 / C3 / C4=170 / 210 / 210 / 210℃

[0111] The masterbatch 2 and the dry blended product were supplied to a twin-screw extruder with a double-hole die (manufactured by Imoto machinery Co., Ltd., 20 mm Φ, L / D = 25) at a ratio of 99.9:0.1 mass %, and the discharged strands were air-cooled and solidified. Next, air was blown to the strands to remove water droplets on the surface of the strands, and then the strands were cut to prepare the resin composition (pellets) of Example 6. The extrusion conditions were set as follows.

[0112] Extruder set temperature: C1 / C2 / C3 / C4=170 / 210 / 210 / 210℃

[0113] <Example 7>

[0114] A resin composition was prepared in the same manner as in Example 6 except that the amount of lycopene in Example 6 was changed as described in Table 2 below.

[0115] <Comparative Example 1>

[0116] 100 mg of β-carotene (B') was added to 3 mL of a mixed solution of tetrahydrofuran:ethanol = "2:1 (volume ratio)", and a slurry was obtained using an ultrasonic vibration device. The obtained slurry was dry-mixed with 1.0 kg of EVOH (A1), and dried at 40°C for 2 hours under vacuum using a vacuum dryer to obtain a mixture 3. The mixture 3 was supplied to a twin-screw extruder with a double-hole die (manufactured by Imoto machinery Co., Ltd., 20 mmΦ, L / D = 25), and the discharged strands were air-cooled and solidified. Then, air was blown into the strands to remove water droplets on the surface of the strands, and then the strands were cut to prepare a resin composition (pellets) of Comparative Example 1 containing 100 ppm of β-carotene. The extrusion conditions were set as follows.

[0117] Extruder set temperature: C1 / C2 / C3 / C4=170 / 210 / 210 / 210℃

[0118] The prepared resin composition was used to perform the following evaluations of thermal stability and YI after heating. The evaluation results of thermal stability are shown in Tables 1 and 2 below, and the evaluation results of YI after heating are shown in Table 3 below.

[0119] <Evaluation of thermal stability>

[0120] (Examples 1 to 5, Comparative Example 1)

[0121] EVOH (A1) or EVOH (A2) was supplied to a twin-screw extruder (manufactured by Imoto machinery Co., Ltd., 20 mm Φ, L / D = 25) with a double-hole die without lycopene (lycopene was 0 ppm), and the discharged strands were air-cooled and solidified. Next, air was blown to the strands to remove water droplets on the surface of the strands, and then the strands were cut to prepare resin compositions (pellets) of EVOH (A1) or EVOH (A2) without lycopene. The extrusion conditions were set as follows.

[0122] Extruder set temperature: C1 / C2 / C3 / C4=170 / 210 / 210 / 210℃

[0123] Using 5 mg each of the resin composition of the above-mentioned EVOH (A1) or EVOH (A2) not containing lycopene, the resin composition of Examples 1 to 5 and Comparative Example 1, a thermogravimetric measuring apparatus (Pyris 1TGA manufactured by Perkin Elmer) was used, under nitrogen atmosphere, air flow rate: 20 mL / min, temperature range: 30 to 550°C, to measure the temperature (5% weight loss temperature) at which the mass decreased to 95% of the mass before measurement. The following Table 1 shows the difference in 5% weight loss temperature of the resin composition of Examples 1 to 5 and Comparative Example 1 relative to the 5% weight loss temperature of the resin composition of EVOH (A1) or EVOH (A2) not containing lycopene. The higher the 5% weight loss temperature (becomes +) compared to the resin composition not containing lycopene, the better the thermal stability.

[0124] <Evaluation of thermal stability>

[0125] (Examples 6 and 7)

[0126] EVOH (A1) 10 mass% and polyethylene (C) 90 mass% were supplied to a twin-screw extruder (manufactured by Imoto machinery Co., Ltd., 20 mm Φ, L / D = 25) with a double-hole die without lycopene (lycopene was 0 ppm), and the discharged strands were air-cooled and solidified. Next, air was blown to the strands to remove water droplets on the surface of the strands, and then the strands were cut to prepare a resin composition (pellet) containing EVOH (A1) 10 mass% and polyethylene (C) 90 mass% without lycopene. The extrusion conditions were set as follows.

[0127] Extruder set temperature: C1 / C2 / C3 / C4=170 / 210 / 210 / 210℃

[0128] Using 5 mg of each of the above resin composition not containing lycopene and the resin composition of Examples 6 and 7, a thermogravimetric measuring apparatus (Pyris 1TGA manufactured by Perkin Elmer) was used to measure the temperature (10% weight loss temperature) at which the mass decreased to 90% of the mass before measurement under the conditions of a nitrogen atmosphere, a gas flow rate of 20 mL / min, and a temperature range of 30 to 550° C. The difference between the 10% weight loss temperature of the resin composition of Examples 6 and 7 and the 10% weight loss temperature of the resin composition not containing lycopene is shown in Table 2 below. The higher the 10% weight loss temperature (becomes +) compared to the resin composition not containing lycopene, the better the thermal stability.

[0129] <Evaluation of YI after heating>

[0130] (Examples 1 and 2)

[0131] The resin composition of the EVOH (A1) not containing lycopene and the resin composition of Examples 1 and 2 were heated in an oven at 150°C for 5 hours, and the obtained composition was filled into a cylinder having an inner diameter of 32 mm and a height of 30 mm. The YI value after heating was measured with a spectrophotometer SE6000 (manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD.) in a rubbed state. The difference in the YI value after heating of the resin composition of Examples 1 and 2 relative to the YI value after heating of the resin composition of EVOH (A1) not containing lycopene is shown in Table 3 below. The lower the YI value after heating (becoming -) compared to the resin composition not containing lycopene, the more suppressed the coloring is.

[0132] [Table 1]

[0133]

[0134] [Table 2]

[0135]

[0136] [Table 3]

[0137]

[0138] As can be seen from Table 1, in Examples 1 to 5, the 5% weight loss temperature increased and the thermal stability improved compared to the resin composition not containing lycopene. On the other hand, in Comparative Example 1 using β-carotene instead of lycopene, the 5% weight loss temperature decreased and the thermal stability decreased compared to the resin composition not containing lycopene.

[0139] As can be seen from Table 3, in Examples 1 and 2, the YI after heating is lowered and the coloring is suppressed compared to the resin composition not containing lycopene.

[0140] As can be seen from Table 2, in Examples 6 and 7, the 10% weight loss temperature is increased compared to the resin composition not containing lycopene, and the thermal stability is improved.

[0141] In addition, the molded article and the multilayered structure obtained from the resin composition have improved thermal stability because the resin composition has thermal stability.

[0142] The above embodiments show specific aspects of the present invention, but the above embodiments are merely examples and are not to be construed as limiting. Various modifications that are obvious to those skilled in the art are intended to be within the scope of the present invention.

[0143] Industrial Applicability

[0144] The resin composition of the present invention has excellent thermal stability and is therefore particularly useful as a variety of packaging materials for various foods, including condiments such as mayonnaise and salad dressings, fermented foods such as mayonnaise, oily foods such as salad oils, beverages, cosmetics, and pharmaceuticals.

Claims

1. A resin composition comprising an ethylene-vinyl alcohol copolymer (A) and lycopene (B).

2. The resin composition according to claim 1, wherein The content of the lycopene (B) is 0.001 to 100 ppm based on the resin composition. The resin composition according to claim 1 , further comprising a polyolefin-based resin (C). 4 . A multilayer structure comprising a layer comprising the resin composition according to claim 1 . 5 . A molded product formed from the resin composition according to claim 1 .

6. A method for producing a resin composition, which is a method for producing the resin composition according to any one of claims 1 to 3, the method comprising the following steps: The ethylene-vinyl alcohol copolymer (A) and lycopene (B) are mixed.

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