Laminates and retort sealant films using a resin composition containing calcium oxide derived from marine organisms.

Abstract

Provided is a sealant film for retort pouched foods that uses a marine organism-derived calcium oxide-containing resin composition and achieves an excellent balance between reduced resin usage and high-temperature heat resistance (compatible with heat-pressure sterilization treatment in the high retort range) [SOLUTION] A laminate comprising a polyethylene-based resin layer I containing 3.0 wt% or more and 50 wt% or less of (A) and 50 wt% or more and 97.0 wt% or less of (B). Component (A): A polyethylene-based resin having the characteristics of (A-i) to (A-iii) (A-i) MFR is 4.0 g / 10 min or more and 20 g / 10 min or less (A-ii) Density of 0.910 g / cm 3 or more and 0.930 g / cm 3 or less (A-iii) The ratio of HLMFR to MFR is 20 to 70 Component (B): A composition consisting of marine organism-derived calcium oxide having the characteristics of (B-i) to (B-ii) and a polyethylene-based resin (B-i) The (Mw / Mn) of the polyethylene-based resin is 8.0 to 15 (B-ii) The average particle size of the marine organism-derived calcium oxide is 10 µm or less

Description

[Technical Field]

[0001] The present invention relates to a laminate, particularly preferably a retort sealant film, using a resin composition containing calcium oxide derived from marine organisms as a raw material. [Background technology]

[0002] Thermoplastic resins are widely used as materials for various molded products and packaging, either as a substitute for paper or in conjunction with it. In light of the trial of the Container Recycling Law and the trend towards resource conservation, there is a need to reduce the amount of raw material resin used. From the perspective of reducing the consumption of thermoplastic resins, for example, thermoplastic resin compositions containing organic material powders, such as wood flour, have been proposed (see Patent Document 1).

[0003] On the other hand, shellfish shells such as scallops have traditionally been treated as industrial waste, with hundreds of thousands of tons discarded annually. However, when these shells are calcined at high temperatures, a calcined powder mainly composed of calcium oxide is obtained, and development is underway to utilize the antibacterial properties of this powder for wall materials, paints, disinfectants, deodorizers, and antifungal agents (see Patent Document 2).

[0004] Under these circumstances, a marine bio-resin composition has been proposed in which inorganic material powder derived from marine organisms is filled into a thermoplastic resin (see Patent Document 3). However, the micronization of the inorganic material powder derived from marine organisms is insufficient, and it is necessary to add a reinforcing agent.

[0005] Furthermore, changes in lifestyle (an increase in single-person households and a shift towards individual meals) are driving increased demand for retort foods. Consequently, demand for retort food packaging materials is also growing. Microwave-safe pouches, in particular, are experiencing rapid growth. In addition, there is a demand for retort food packaging materials suitable not only for room-temperature storage but also for low-temperature distribution (frozen to chilled). Examples of such film configurations include the following: PET / / Ny / / PO, vapor-deposited PET / / Ny / / PO (Here, PO means PP (polypropylene) or PE (polyethylene), PET is polyethylene terephthalate, Ny is nylon, and / / means adhesive. The same applies below.) [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2012-172147 [Patent Document 2] Japanese Patent Publication No. 2007-284294 [Patent Document 3] Japanese Patent Publication No. 2022-63566 [Overview of the project] [Problems that the invention aims to solve]

[0007] The object of the present invention is to provide a sealant film for retort foods that uses a finely milled marine biological-derived calcium oxide-containing resin composition and offers an excellent balance between reduced use of thermoplastic resin and high-temperature heat resistance (suitable for heat-pressure sterilization in the high-retort range (over 120°C to under 130°C)). [Means for solving the problem]

[0008] The inventors of the present invention diligently studied to solve the above problems and found that the problems could be solved by laminating a specific ethylene-α-olefin copolymer, a specific high-density polyethylene, and a specific marine biological-derived calcium oxide-containing resin composition. Based on these findings, further studies were conducted to complete the present invention.

[0009] In other words, according to the present invention [1], a laminate comprising at least three or more layers, characterized in that it contains a polyethylene resin layer I containing the following component (A) in an amount of 3.0% by weight or more and 50% by weight or less, and the following component (B) in an amount of 50% by weight or more and 97.0% by weight or less. Component (A): Polyethylene resin having the following properties (Ai) to (A-iii) (Ai) Melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg is 4.0 g / 10 min or higher and 20 g / 10 min or lower. (A-ii) Density is 0.910 g / cm³ 3 More than 0.930g / cm 3 below (A-iii) The ratio (HLMFR / MFR) of the melt flow rate (HLMFR) at a temperature of 190°C and a load of 21.6 kg to the melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg is between 20 and 70. Component (B): A composition consisting of marine biological-derived calcium oxide and polyethylene resin having the following properties (Bi) to (B-ii). The molecular weight distribution (Mw / Mn), which is the ratio of the number-average molecular weight (Mn) to the weight-average molecular weight (Mw) obtained from GPC (Gel Permeation Chromatography) of (Bi) polyethylene resins, is between 8.0 and 15. (B-ii) Calcium oxide of marine organism origin with an average particle size of 10 μm or less

[0010] Furthermore, according to the present invention [2], a laminate comprising at least a first layer, a second layer and a third layer stacked in this order, wherein the first and third layers consist of polyethylene resin layers II containing 5.0% by weight or more and 60% by weight or less of component (C) and 40% by weight or more and 95.0% by weight or less of component (D), and the second layer consists of polyethylene resin layers I containing component (A) and component (B). Component (A): Polyethylene resin having the following properties (Ai) to (A-iii) (A-i) a melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg of 4.0 g / 10 min or more and 20 g / 10 min or less (A-ii) a density of 0.910 g / cm 3 or more and 0.930 g / cm 3 or less (A-iii) a ratio (HLMFR / MFR) of a high-load melt flow rate (HLMFR) at a temperature of 190°C and a load of 21.6 kg to the melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg of 20 to 70 Component (B): a composition comprising marine organism-derived calcium oxide having the following properties (B-i) to (B-ii) and a polyethylene resin (B-i) a molecular weight distribution (Mw / Mn) which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) determined by GPC (Gel Permeation Chromatography) of the polyethylene resin of 8.0 to 15 (B-ii) an average particle diameter of the marine organism-derived calcium oxide of 10 µm or less Component (C): a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms having the following properties (C-i) to (C-ii) (C-i) a melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg of 0.1 g / 10 min or more and 5.0 g / 10 min or less (C-ii) a density of 0.910 g / cm3 or more and 0.930 g / cm3 or less Component (D): a polyethylene resin having the following properties (D-i) to (D-iii) (D-i) a melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg of 0.1 g / 10 min or more and 10 g / 10 min or less (D-ii) a density of 0.945 g / cm 3 or more and 0.975 g / cm 3 or less (D-iii) a molecular weight distribution (Mw / Mn) which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) determined by GPC (Gel Permeation Chromatography) of 1.0 to 10

[0011] Furthermore, according to the present invention [3], the first layer has a treated surface on the side opposite to the second layer side which is subjected to corona treatment during molding, and the third layer has a heat-sealed surface on the side opposite to the second layer side which is subjected to heat sealing, as described in the second invention. Furthermore, according to the present invention [4], the retort sealant film is obtained by laminating a base material layer selected from PET, Ny, OPP, and AL on the treated surface side of the retort sealant film described in the third invention. Furthermore, according to the present invention [5], a pouch is provided that uses the retort sealant film described in the fourth invention. [Effects of the Invention]

[0012] Laminates made from the marine bio-derived calcium oxide-containing resin composition of the present invention have an excellent balance between impact resistance (dirt drop impact) and heat seal strength, making them particularly suitable for retort sealant films, standing pouches, BIBs (bag-in-boxes), inner bags, agricultural films, and the like. [Modes for carrying out the invention]

[0013] This invention relates to a retort sealant film made from a resin composition containing calcium oxide derived from marine organisms. The present invention will be described below item by item.

[0014] The present invention relates to a laminate comprising at least three or more layers, characterized in that it includes a layer containing a composition comprising a specific ethylene-α-olefin copolymer and a specific marine biological-derived calcium oxide and polyethylene resin.

[0015] 1. Polyethylene resin layer I The polyethylene-based resin layer I of the laminate of the present invention only needs to contain an ethylene-α-olefin copolymer (component (A)) and a composition composed of marine organism-derived calcium oxide and a polyethylene-based resin (component (B)). Preferably, it consists of a polyethylene-based resin layer II containing 3.0% by weight or more and 50% by weight or less of the polyethylene-based resin (component (A)), and 50% by weight or more and 97% by weight or less of the composition composed of marine organism-derived calcium oxide and a polyethylene-based resin (component (B)). (1) Component A (A-i) The melt flow rate (MFR) of component (A) used for the polyethylene-based resin layer I included in the laminate of the present invention, measured at a temperature of 190°C and a load of 2.16 kg, is 4.0 g / 10 min or more and 20 g / 10 min or less, preferably 5.0 g / 10 min or more and 15 g / 10 min or less, more preferably 6.0 g / 10 min or more and 10 g / 10 min or less. When the MFR of component (A) is 4.0 g / 10 min or more, the resin pressure is low and the fluidity is good; when it is 20 g / 10 min or less, bubbles are stabilized during inflation molding, the moldability is good, and there is no risk of the inorganic filler exhibiting uneven distribution behavior in the resin, which is preferable. In the present invention, the MFR of a polyethylene-based resin refers to the value measured under the conditions of 190°C and a load of 21.18 N (2.16 kg) in accordance with JIS K7210 "Plastics - Test methods for melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastics". (A-ii) Density The density of component (A) used for the polyethylene-based resin layer I included in the laminate of the present invention is 0.910 g / cm 3 or more, 0.930 g / cm 3 or less, preferably 0.915 g / cm 3 or more, 0.925 g / cm 3 or less. When the density of component (A) is 0.910 g / cm 3 or more, there is no risk that the sealant film will melt after heat-pressurization sterilization treatment at more than 120°C to less than 130°C; when it is 0.930 g / cm 3The following is preferable, as it does not risk a decrease in low-temperature impact strength. In this invention, the density of the polyethylene resin composition refers to the value obtained by the following method. Here, the density of the polyethylene resin component (A) is measured at 23°C, referring to the JIS K6922-2:2023 Annex (for low-density polyethylene). (A-iii) HLMFR / MFR The HLMFR / MFR of component (A) used in the polyethylene resin layer I contained in the laminate of the present invention is 20 or more and 70 or less, preferably 25 or more and 60 or less, and more preferably 30 or more and 50 or less. HLMFR / MFR has a strong correlation with molecular weight distribution; when HLMFR / MFR is large, the molecular weight distribution becomes broad, and when HLMFR / MFR is small, the molecular weight distribution becomes narrow. When HLMFR / MFR is 20 or more and 70 or less, bubbles become stable during inflation molding and moldability is improved.

[0016] (2) Component B The composition (component (B)) used in the polyethylene resin layer I of the laminate of the present invention, consisting of marine biological-derived calcium oxide and polyethylene resin, has the following properties (Bi) to (B-ii).

[0017] (Bi) Ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (Mw / Mn) The ratio (Mw / Mn) of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of component (B) used in the polyethylene resin layer I contained in the laminate of the present invention is 8.0 or more and 15 or less, preferably 9.0 or more and 14 or less, and more preferably 10 or more and 13 or less. A ratio (Mw / Mn) of 8.0 or more is preferable because there is no risk of the resin pressure increasing during molding. Furthermore, a ratio (Mw / Mn) of 15 or less is preferable because there is no risk of a decrease in low-temperature impact strength. (B-ii) Average particle size The average particle size of the marine biological-derived calcium oxide component (B) used in the polyethylene resin layer I contained in the laminate of the present invention is 10 μm or less, preferably 9 μm or less, and more preferably 8 μm or less. If the average particle size of marine biological-derived calcium oxide is 10 μm or less, there is no risk of the inorganic filler exhibiting uneven distribution behavior in the resin, nor is there a risk of a decrease in the interfacial strength of the film.

[0018] (3) Other additives The polyethylene resin layer I contained in the laminate of the present invention may contain other optional components, as long as they do not significantly impair the effects of the present invention. Examples of such optional components include antioxidants commonly used in polyethylene resin materials (phenol-based and phosphorus-based antioxidants are preferred), antiblocking agents, neutralizing agents, heat stabilizers, crystal nucleating agents, clearing agents, lubricants, colorants, dispersants, peroxides, fillers, fluorescent whitening agents, and the like. Furthermore, to impart flexibility, rubber compounds such as ethylene-α-olefin elastomers like EBR and EPR, and styrene-based elastomers like SEBS and HSBR can be incorporated. In particular, it is preferable to add component (E), described later, as a further resin component. When adding component (E), the ratio is in the range of 0.1 to 10% by weight, preferably 0.5 to 5% by weight, relative to 100% by weight of the total amount of resin components constituting the polyethylene resin layer I.

[0019] (4) Component (E) The thermoplastic resin (component E) that can be used in the laminate of the present invention has the following properties (Ei) to (E-iii). (Ei) Ethylene copolymer, which is a copolymer containing ethylene and a radical polymerizable acid anhydride as constituent monomers. (E-ii) Polyhydric alcohol compounds having two or more hydroxyl groups in the molecule (E-iii) Reaction accelerator

[0020] (5) The proportion of ingredients (A) and (B) The polyethylene resin layer I contained in the laminate of the present invention may contain component (A) and component (B). A preferred blending ratio of component (A) to component (B) is 3.0% to 50% by weight for component (A) and 50% to 97.0% by weight for component (B). Preferably, component (A) is 5.0% to 40% by weight and component (B) is 60% to 95.0% by weight. More preferably, component (A) is 7.5% to 37% by weight and component (B) is 63% to 92.5% by weight. (The total amount of resin components constituting resin layer I is taken as 100% by weight.) The inclusion of components (A) and (B) is preferable because it does not lead to deterioration of moldability and is expected to reduce the consumption of thermoplastic resin.

[0021] 2. Polyethylene resin layer II The polyethylene resin layer II contained in the laminate of the present invention may contain ethylene-α-olefin copolymer (component (C)) and polyethylene resin (component (D)), but preferably consists of an ethylene resin layer II containing 5.0% to 60% by weight of ethylene-α-olefin copolymer (component (C)) and 40% to 95% by weight of polyethylene resin (component (D)).

[0022] (1) Component (C) The polyethylene resin layer II included in the laminate of the present invention uses an ethylene-α-olefin copolymer (component (C)), which is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms. This copolymer has the following properties (Ci) to (C-ii), preferably (Ci) to (Cv). (Ci) Melt Flow Rate (MFR) The melt flow rate (MFR) of component (C) used in the polyethylene resin layer II contained in the laminate of the present invention, measured at a temperature of 190°C and a load of 2.16 kg, is 0.1 g / 10 min or more and 5.0 g / 10 min or less, preferably 0.5 g / 10 min or more and 3.0 g / 10 min or less. When the MFR of component (C) is 0.1 g / 10 min or more, the resin pressure is low and moldability is good. When it is 5.0 g / 10 min or less, the bubbles become stable during inflation molding and moldability is good. Furthermore, there is no risk of poor heat resistance behavior such as wrinkles forming in the sealant film after heat pressurized sterilization treatment at temperatures above 120°C to below 130°C, which is preferable. In this invention, the MFR of the ethylene-α-olefin copolymer refers to the value measured under conditions of 190°C and a load of 21.18 N (2.16 kg) in accordance with JIS K7210 "Plastics - Test methods for melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastic plastics". (C-ii) Density The density of component (C) used in the polyethylene resin layer II contained in the laminate of the present invention is 0.910 g / cm³. 3 More than 0.930g / cm 3 Preferably, 0.915 g / cm³ 3 More than 0.925g / cm 3 The following is true: The density of component (A) is 0.910 g / cm³. 3 In the above case, there is no risk of the sealant film melting after heat and pressure sterilization treatment at temperatures above 120°C but below 130°C, and the concentration is 0.930 g / cm³. 3 The following is preferable, as it does not risk a decrease in low-temperature impact strength. In this invention, the density of the polyethylene resin composition refers to the value obtained by the following method. Here, the density of component (C), the ethylene-α-olefin copolymer, is given by JIS K692 Refer to Annex 2-2:2023 (for low-density polyethylene) and measure at 23°C.

[0023] (C-iii) Monomer composition The component (C) used in the polyethylene resin layer II contained in the laminate of the present invention is a random copolymer of ethylene and α-olefin, with constituent units derived from ethylene as the main component. The α-olefin used as the comonomer is preferably an α-olefin having 3 to 12 carbon atoms. Specifically, examples include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methylpentene-1, 4-methylhexene-1, 4,4-dimethylpentene-1, etc. Specific examples of such ethylene-α-olefin copolymers include ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, and ethylene-4-methylpentene-1 copolymer. In addition, the α-olefin may be one type or a combination of two or more types. When two types of α-olefins are combined to form a terpolymer, examples include ethylene-propylene-hexecenter polymer, ethylene-butene-hexecenter polymer, ethylene-propylene-octenoterpolymer, and ethylene-butene-octenoterpolymer.

[0024] (C-iv) Polymerization catalysts and polymerization methods The component (C) used in the polyethylene resin layer II contained in the laminate of the present invention can be produced using a Ziegler catalyst, a vanadium catalyst, a metallocene catalyst, preferably a metallocene catalyst. Production methods include high-pressure ionic polymerization, gas-phase polymerization, solution polymerization, and slurry polymerization. (Cv)α-olefin content The α-olefin content in the ethylene-α-olefin copolymer of component (C) used in the polyethylene resin layer II contained in the laminate of the present invention is preferably 3% by weight or more and 40% by weight or less, more preferably 5% by weight or more and 30% by weight or less, and even more preferably 8% by weight or more and 20% by weight or less. When the α-olefin content is 3% by weight or more, the impact strength and flexibility of the film are obtained, and when it is 40% by weight or less, the heat resistance is not impaired. Here, the α-olefin content is a value measured by 13C-NMR under the following conditions. Device: JEOL-GSX270 (manufactured by JEOL Corporation) Concentration: 300mg / 2mL Solvent: Orthodichlorobenzene

[0025] The ethylene-α-olefin copolymer of component (C) may be one type or a mixture of two or more types.

[0026] (2) Component (D) The polyethylene resin (component (D)) used in the polyethylene resin layer II contained in the laminate of the present invention has the following characteristics (Di) to (D-iii). (Di) Melt Flow Rate (MFR) The melt flow rate (MFR) of component (D) used in the polyethylene resin layer II contained in the laminate of the present invention, measured at a temperature of 190°C and a load of 2.16 kg, is 0.1 g / 10 min or more and 10 g / 10 min or less, preferably 0.3 g / 10 min or more and 5.0 g / 10 min or less. When the MFR of component (D) is 0.1 g / 10 min or more, the resin pressure is low and moldability is good. When it is 5.0 g / 10 min or less, the bubbles become stable during inflation molding and moldability is good. Furthermore, there is no risk of poor heat resistance behavior such as wrinkles forming in the sealant film after heat pressurized sterilization treatment at temperatures above 120°C to below 130°C, which is preferable. In this invention, the MFR of the ethylene-α-olefin copolymer refers to the value measured under conditions of 190°C and a load of 21.18 N (2.16 kg) in accordance with JIS K7210 "Plastics - Test methods for melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastic plastics". (D-ii) Density The density of component (D) used in the polyethylene resin layer II contained in the laminate of the present invention is 0.945 g / cm³. 3 More than 0.975g / cm 3 Preferably 0.950 cm 3 More than 0.970g / cm 3 The following is true: The density of component (D) is 0.945 g / cm³. 3In the above case, there is no risk of the sealant film melting after heat and pressure sterilization treatment at temperatures above 120°C but below 130°C, and the concentration is 0.975 g / cm³. 3 The following is preferable, as it does not risk a decrease in low-temperature impact strength. In this invention, the density of the polyethylene resin composition refers to the value obtained by the following method. Here, the density of the polyethylene resin component (D) is measured at 23°C, referring to the JIS K6922-2:2023 Annex (for high-density polyethylene). (D-iii) Ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (Mw / Mn) The ratio (Mw / Mn) of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of component (D) used in the polyethylene resin layer II contained in the laminate of the present invention is 1.0 or more and 10 or less, preferably 1.5 or more and 9 or less, and more preferably 3.0 or more and 8.5 or less. A ratio (Mw / Mn) of 1.0 or more is preferable because there is no risk of the resin pressure increasing during molding. Furthermore, a ratio (Mw / Mn) of 10 or less is preferable because there is no risk of a decrease in low-temperature impact strength. Methods for adjusting Mw / Mn to a predetermined range include selecting an appropriate metallocene catalyst. Note that the (Mw / Mn) ratio is measured using gel permeation chromatography (GPC). The measurement was performed under the following conditions: Equipment: Waters GPC 150C type detector: MIRAN 1A infrared spectrophotometer (measurement wavelength, 3.42 μm) Columns: Showa Denko AD806M / S (3 pieces) [The column was calibrated by measuring monodisperse polystyrene (A500, A2500, F1, F2, F4, F10, F20, F40, F288, each at 0.5 mg / ml solution) manufactured by Tosoh Corporation. The logarithm of the elution deposition and molecular weight was approximated by a quadratic equation. Furthermore, the molecular weight of the samples was converted to polyethylene equivalent using the viscosity equations for polystyrene and polyethylene. Here, the relationship for polyethylene viscosity equations is α = 0.723, logK = -3.967, and for polyethylene, it is α = -0.723, logK = -3.407.] Measurement temperature: 140℃ Injection amount: 0.2ml Concentration: 20mg / 10ml Solvent: Orthodichlorobenzene Flow rate: 1.0ml / min

[0027] (3) Other additives Other optional components may be added to the polyethylene resin layer II of the present invention, as long as they do not significantly impair the effects of the present invention. Examples of such optional components include antioxidants commonly used in polyethylene resin materials (phenol-based and phosphorus-based antioxidants are preferred), antiblocking agents, neutralizing agents, heat stabilizers, crystal nucleating agents, clearing agents, lubricants, colorants, dispersants, peroxides, fillers, fluorescent whitening agents, and the like. Furthermore, to impart flexibility, rubber compounds such as ethylene-α-olefin elastomers like EBR and EPR, and styrene-based elastomers like SEBS and HSBR can be incorporated. In particular, it is preferable to further add component (E) as a resin component. When adding component (E), the ratio is in the range of 0.1 to 10% by weight, preferably 0.5 to 5% by weight, based on 100% by weight of the total amount of resin components constituting the polyethylene resin layer II.

[0028] (4) The proportion of ingredients (C) and (D) The ethylene-based resin layer II of the present invention may contain component (C) and component (D). A preferred blending ratio of component (C) to component (D) is 5.0% to 60% by weight for component (C) and 40% to 95.0% by weight for component (D). Preferably, component (C) is 10% to 50% by weight for component (C) and 50% to 90% by weight for component (D). More preferably, component (C) is 15% to 45% by weight for component (D) and 65% to 85% by weight for component (D). (The total amount of resin components constituting the ethylene-based resin layer II is considered to be 100% by weight.) The inclusion of components (C) and (D) is preferable because it prevents the sealant film from exhibiting poor heat resistance, such as wrinkle formation, after heat and pressure sterilization treatment at temperatures above 120°C but below 130°C.

[0029] 3. Polyethylene film • Polyethylene resin composition to be used A film made from a polyethylene resin composition that satisfies the requirements of the present invention is a film characterized by comprising at least one layer made of polyethylene resin composition, wherein this layer can be sealed by fusion. There are no particular limitations on the polyethylene resin compositions that can be used, but examples include ultra-low density polyethylene (ULDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE).

[0030] • Additives The polyethylene resin composition used in polyethylene films may contain additives commonly used in resin compositions, such as antioxidants, heat stabilizers, neutralizing agents, antiblocking agents, tackifiers, antistatic agents, slip agents, nucleating agents, foaming agents, crosslinking agents, biomass resources, and biodegradation accelerators, to the extent that they do not impair the film's functionality. Furthermore, the additives used in the film made from a polyethylene resin composition that satisfies the requirements of the present invention preferably contain an antiblocking agent in an amount of 4000 ppm or less and a slip agent in an amount of 600 ppm or less. More preferably, the antiblocking agent is 2000 ppm or less and the slip agent is 300 ppm or less.

[0031] • Method and manufacturing conditions for polyethylene film Known techniques can be used for manufacturing polyethylene film. Specifically, these include inflation molding, T-die molding, and calendering, but inflation molding and T-die molding are preferred.

[0032] • Polyethylene film structure The polyethylene film may have a single-layer or multi-layer structure. In the case of a single-layer structure, the polyethylene resin composition may be used alone or mixed with other polyethylene resin compositions. In the case of a multi-layer structure, it is preferable to use the above-mentioned known techniques and to form it by co-extrusion molding, and it is preferable to have at least three layers.

[0033] 4. Laminate • Multilayer film In addition to a film composed of a polyethylene resin composition that satisfies the requirements of the present invention, the present invention may also be a film obtained by laminating layers of films made from at least one polyethylene resin composition and obtained by inflation molding or T-die molding. Examples of resins that can be used include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ultra-low-density polyethylene (ULDPE). Furthermore, the lamination method may involve further stretching of a co-extruded film obtained by co-extrusion molding, or by bonding the films together using an adhesive.

[0034] ·glue Adhesives can be used to laminate the above-mentioned resin laminates. The adhesive used contains at least one resin composition, but is not particularly limited. Examples of adhesives that can be used include epoxy, acrylic, and urethane types. Furthermore, there are no particular limitations on the adhesive containing any of the above-mentioned resin compositions, but one-component, two-component, or hot-melt types can be used as needed.

[0035] 5. Packaging materials A laminate having at least one film layer made of a polyethylene resin composition that satisfies the requirements of the present invention is particularly suitable for use as a packaging material. The shape of the packaging material is not particularly limited and may be a packaging bag or a stand-up pouch. In the case of a stand-up pouch, the body may be formed only of the resin laminate, the bottom may be formed only of the resin laminate, or both the body and the bottom may be formed of the resin laminate.

[0036] ·Packaging bag The bag-shaped packaging material can be manufactured by folding the laminated material in half and overlapping the two halves so that the heat-sealed layer faces inward, and then heat-sealing the edges. Furthermore, bag-shaped packaging materials can also be manufactured by overlapping two laminated materials so that the heat-sealed layers face each other, and then heat-sealing the edges.

[0037] ·Applications The retort sealant film made of the laminate of the present invention is particularly suitable for use in heat-pressure sterilization treatments at temperatures above 120°C and below 130°C. Furthermore, the retort sealant film made of the laminate of the present invention can also be suitably used when PE / / AL / / PET and PET / / AL / / Ny are laminated on the processing surface side and then vertically pillow-packaged in an automatic liquid filling machine. Specifically, the range of possible sealing temperatures (where no liquid leakage is observed) is widened. It offers an excellent balance between sealing temperature and pressure resistance. [Examples]

[0038] The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The evaluation methods, analytical methods, and materials used in the examples are as follows.

[0039] 1. Methods for measuring physical properties (1) MFR Measurements were taken in accordance with JIS K6922-2, under conditions of 190°C and a 2.16 kg load. (2) Density Measurements were taken in accordance with JIS K6922-1 and 2. (3)Molecular weight distribution The molecular weight (number-average molecular weight (Mn), weight-average molecular weight (Mw), and Z-average molecular weight (Mz)) was measured using GPC, and the molecular weight distribution [ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (Mw / Mn)] was calculated.

[0040] 2. Film Evaluation Method (1) Dirt Drop Impact (Dirt Drop Impact Strength) Measurements were taken in accordance with JIS K 7124 1 A method.

[0041] 3.Resin used (1) Low-density polyethylene (A) A-1: Manufactured by Nippon Polyethylene Co., Ltd., product name Novatec LD, low-density polyethylene, grade name: LC605A, MFR = 7.0 g / 10 min, density = 0.918 g / cm³ 3 (2) Marine bio-derived calcium oxide-containing resin composition (B) B-1: Calcium oxide masterbatch derived from scallop shells, calcium oxide concentration = 55%, average particle size = 4 μm, polyethylene resin = LC605A, Mw / Mn = 11.6 B-2: Calcium oxide masterbatch derived from scallop shells, calcium oxide concentration = 45%, average particle size = 8 μm, polyethylene resin = NC596A, Mw / Mn = 3.2 (3) Ethylene-α-olefin copolymer (C) C-1: Manufactured by Nippon Polyethylene Co., Ltd., product name: Harmolex, metallocene-based linear low-density polyethylene, grade name: NF366A, MFR = 1.6 g / 10 min, density = 0.919 g / cm³ 3 C-2: Manufactured by Nippon Polyethylene Co., Ltd., product name: Harmolex, metallocene-based linear low-density polyethylene, grade name: NF396A, MFR = 1.3g / 10min, density = 0.935g / cm³ 3 (4) High-density polyethylene (D) D-1: Manufactured by Nippon Polyethylene Co., Ltd., product name Novatec HD, high-density polyethylene, grade name: HY540, MFR = 1.1g / 10min, density = 0.960g / cm³ 3 (5) Masterbatch F-1: Manufactured by Nippon Polyethylene Co., Ltd., Antiblocking agent masterbatch, Grade name: KMB16F, Antiblocking agent 16% by weight masterbatch F-2: Manufactured by Nippon Polyethylene Co., Ltd., slip agent masterbatch, Grade name: KMB05S, 5% by weight slip agent masterbatch

[0042] 4.3 Forming of 3-layer air-cooled inflation film A single-layer inflation film was formed using the following molding apparatus and molding conditions. Equipment: Air-cooled inflation molding machine (Equipment name: DIREX, Manufacturer: Placo Co., Ltd.) Extruder screw diameter: Outer layer (Layer I) / Intermediate layer (Layer II) / Inner layer (Layer III) = 50mmφ / 55mmφ / 50mmφ Die diameter: 200mmφ Extrusion rate: 60 kg / hr Die lip gap: 3mm Pickup speed: 14m / min Blow-up ratio: 2.0 Molding resin temperature: 180℃ Film thickness: 50 μm Cooling ring: 2-stage air cooling ring Corona treatment applied (initial wetting tension: 45 dyn / cm or higher)

[0043] [Table 1]

[0044] (Examples 1-3, Comparative Examples 1-2) Using the raw materials listed in Table 1 from the above-mentioned raw materials, inflation molding was performed according to "4.3 Forming of 3-layer air-cooled inflation films" to obtain films. The conditions for inflation molding and formability are shown in Table 2. The obtained films were evaluated for dirt drop impact strength (DDI) and heat resistance. The evaluation results are shown in Table 2.

[0045] [Table 2]

[0046] (evaluation) The results shown in Table 2 clearly demonstrate that Examples 1 to 3, which satisfy the requirements of the present invention, exhibit improved moldability during inflation molding and superior dirt drop impact and heat resistance of the laminate. [Industrial applicability]

[0047] The sealant film for retort foods made of the laminate of the present invention has an excellent balance between low-temperature impact resistance and high-temperature heat resistance in the high-retort region (above 120°C to below 130°C), making it suitable for use not only in room temperature storage but also in low-temperature distribution (frozen to chilled).

Claims

1. A laminate comprising at least three layers, characterized in that it includes a polyethylene resin layer I containing 3.0% by weight or more and 50% by weight or less of the following component (A), and 50% by weight or more and 97.0% by weight or less of the following component (B). Component (A): Polyethylene resin having the following properties (A-i) to (A-iii) (A-i) Melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg is 4.0 g / 10 min or more and 20 g / 10 min or less. (A-ii) Density of 0.910 g / cm³ ３ Above, 0.930g / cm ３ below (A-iii) The ratio (HLMFR / MFR) of the melt flow rate (HLMFR) at a temperature of 190°C and a load of 21.6 kg to the melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg is between 20 and 70. Component (B): A composition consisting of marine biological-derived calcium oxide and polyethylene resin having the following properties (B-i) to (B-ii). (B-i) The molecular weight distribution (Mw / Mn), which is the ratio of the number-average molecular weight (Mn) to the weight-average molecular weight (Mw) obtained from the GPC (Gel Permeation Chromatography) of polyethylene resins, is between 8.0 and 15. (B-ii) Average particle size of marine organism-derived calcium oxide is 10 μm or less.

2. A laminate comprising at least a first layer, a second layer, and a third layer stacked in this order, wherein the first and third layers consist of polyethylene resin layers II containing 5.0% to 60% by weight of component (C) and 40% to 95.0% by weight of component (D), and the second layer consists of polyethylene resin layers I containing component (A) and component (B). Component (A): Polyethylene resin having the following properties (A-i) to (A-iii) (A-i) Melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg is 4.0 g / 10 min or more and 20 g / 10 min or less. (A-ii) Density of 0.910 g / cm³ ３ Above, 0.930g / cm ３ below (A-iii) The ratio (HLMFR / MFR) of the melt flow rate (HLMFR) at a temperature of 190°C and a load of 21.6 kg to the melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg is between 20 and 70. Component (B): A composition consisting of marine biological-derived calcium oxide and polyethylene resin having the following properties (B-i) to (B-ii). (B-i) The molecular weight distribution (Mw / Mn), which is the ratio of the number-average molecular weight (Mn) to the weight-average molecular weight (Mw) obtained from the GPC (Gel Permeation Chromatography) of polyethylene resins, is between 8.0 and 15. (B-ii) Average particle size of marine organism-derived calcium oxide is 10 μm or less. Component (C): Copolymer of ethylene having the following properties (C-i) to (C-ii) and α-olefins having 3 to 12 carbon atoms. (C-i) Melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg is 0.1 g / 10 min or more and 5.0 g / 10 min or less. (C-ii) Density of 0.910 g / cm³ ３ Above, 0.930g / cm ３ below Component (D): Polyethylene resin having the following characteristics (D-i) to (D-iii) (D-i) Melt flow rate (MFR) measured at a temperature of 190°C and a load of 2.16 kg is 0.1 g / 10 min or more and 10 g / 10 min or less. (D-ii) Density of 0.945 g / cm³ ３ Above, 0.975g / cm ３ below (D-iii) The molecular weight distribution (Mw / Mn), which is the ratio of the number-average molecular weight (Mn) to the weight-average molecular weight (Mw) obtained from GPC (Gel Permeation Chromatography), is between 1.0 and 10.

3. A retort sealant film using a laminate according to claim 2, wherein the first layer has a treated surface on the side opposite to the side facing the second layer, which is corona treated during molding, and the third layer has a heat-sealed surface on the side opposite to the side facing the second layer.

4. A retort sealant film according to claim 3, wherein a base material layer selected from PET, Ny, OPP, and AL is laminated on the treated surface side of the retort sealant film.

5. A pouch using the retort sealant film described in claim 4.

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