High heat-resistant and low odor gas adsorption sealant film

Abstract

To provide a high heat resistant sealant film which adsorbs gas generated from the film itself and gas from a space in contact with the film, has little gas emission, suppresses entrance and exit of gas from / to a package and emission of the gas due to degradation with time, and can resist temperatures from boil to semi-retort sterilization treatment.SOLUTION: A high heat resistant and low odor gas sealant film 1 contains a high heat resistant and low odor resin having heat sealability, and a gas adsorbent 4b, and adsorbs gas generated from the film itself and gas (one or two or more kinds selected from hydrocarbons, aldehydes, ketones and carboxylic acids) from the outside, wherein the high heat resistant and low odor resin has a density of 0.920 g / cm3 or more and 0.960 g / cm3 or less, concentration of total leachable organic carbon (TOC) contained in the film composed of the high heat resistant and low odor resin is 1.5 ppm or more and 250 ppm or less, and the total organic carbon is eluted by boiling treatment at 90-110°C for 30 minutes and stationary storage at 35°C.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a highly heat-resistant and low-odor gas adsorption sealing film that adsorbs gases generated from itself and gases from the surrounding space, and has a low gas emission amount even when heated, without causing a change in the odor of the contents.

Background Art

[0002] In recent years, for the purpose of preventing contamination, deterioration, and odor change of the contents of a package, a packaging material containing an odor adsorbent that adsorbs odors has been proposed (Patent Document 1). In such a packaging material, an odor adsorbent such as synthetic zeolite or activated carbon is kneaded into a resin material. There is also known a packaging material containing an odor adsorbent in which a chemisorbent is supported on an inorganic porous body (Patent Document 2). However, the main adsorption target is only to adsorb odor components having a specific functional group, and in a situation where a resin material is not selected, the generation amount of organic substances having no functional group cannot be suppressed, and it is not possible to sufficiently adsorb odor components. Furthermore, a hygroscopic packaging material that suppresses the generation of off-odors due to hydrolysis of the contents is also known (Patent Document 3). Although it has an odor generation suppression effect, since the generated odor components remain as they are, a sufficient odor improvement effect cannot be obtained. In addition, for applications used in high-temperature sterilization treatments such as retort sterilization and high-temperature boiling, a lid material film having a functional resin layer containing an oxygen absorber and a gas adsorbent has been proposed to reduce residual odors and improve odor in the package (Patent Document 4). However, it cannot adsorb all the resin decomposition components generated when expressing oxygen absorption characteristics, and since it is a lid material film, an easy-peel layer is formed on the inner layer surface, so it is not suitable for general use.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

[0004] An object of the present invention is to provide a sealing film that has high heat resistance to withstand the temperature of semi-retort heat treatment (90 to 110°C) from a boiler, emits little gas from itself, adsorbs gas from the outside in contact therewith, and suppresses changes in the odor of the contents. [Means for Solving the Problems]

[0005] As a result of various studies, the present inventors have found that a sealing film containing at least a specific high heat resistance and low odor resin and a gas adsorbent achieves the above object. That is, the present invention is characterized by the following points. 1. A high heat resistance, low odor gas adsorption sealing film, The high heat resistance, low odor gas adsorption sealing film contains a high heat resistance, low odor resin having heat sealability and a gas adsorbent, and adsorbs gas generated from itself and gas from the outside. The gas is one or a combination of two or more selected from the group consisting of hydrocarbons, aldehydes, ketones, and carboxylic acids. The high heat resistance, low odor resin has a density of 0.920 g / cm 3 or more and 0.960 g / cm 3 or less, and the concentration of eluted total organic carbon (TOC) contained in the film made of the high heat resistance, low odor resin is 1.5 ppm or more and 250 ppm or less, and elutes by boiling treatment at 90 to 110°C for 30 minutes and static storage at 35°C. The high heat resistance, low odor gas adsorption sealing film as described above. 2. In the resin contained in the full-height heat-resistant low-odor gas adsorption sealant film, the content of the high heat-resistant low-odor resin is 70% by mass or more and 100% by mass or less. The content of the gas adsorbent is 0.1% by mass or more and 30% by mass or less in the layer containing the gas adsorbent, which is characterized by The high heat-resistant low-odor gas adsorption sealant film according to 1 above. 3. The high heat-resistant low-odor resin is a polyethylene-based resin, and the high heat-resistant low-odor gas adsorption sealant film according to 1 or 2 above is characterized by this. 4. The high heat-resistant low-odor resin is one or a combination of two or more selected from the group consisting of high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene, and the high heat-resistant low-odor gas adsorption sealant film according to 1 or 2 above is characterized by this. 5. The gas adsorbent contains one or a combination of two or more selected from the group consisting of hydrophobic zeolite, molecular sieve, metal-organic framework (MOF), and activated carbon, and the high heat-resistant low-odor gas adsorption sealant film according to any one of 1 to 4 above is characterized by this. 6. The high heat-resistant low-odor gas adsorption sealant film has a gas adsorption layer and a heat-sealing layer. The gas adsorption layer is a layer containing the high heat-resistant low-odor resin and the gas adsorbent. The heat-sealing layer is a layer containing the high heat-resistant low-odor resin and having heat-sealing properties. At least one outermost layer on one side of the high heat-resistant low-odor gas adsorption sealant film is a heat-sealing layer. The high heat-resistant low-odor resin contained in the gas adsorption layer and the high heat-resistant low-odor resin contained in the heat-sealing layer are the same or different, which is characterized by The high heat-resistant low-odor gas adsorption sealant film according to any one of 1 to 5 above. 7. When boiled at a temperature of 90 °C or more and 100 °C or less for 10 minutes or more and 60 minutes or less, the heat shrinkage rate is 0% or more and 10% or less. It is characterized in that there is no change like a slippery skin on the surface. The high heat-resistant and low odor gas adsorption sealant film according to any one of 1 to 6 above. 8. A high heat-resistant and low odor gas adsorption sealant film for retort sterilization or semi-retort sterilization, using the high heat-resistant and low odor gas adsorption sealant film according to any one of 1 to 7 above.

Effects of the Invention

[0006] According to the present invention, a sealant film can be obtained which has high heat resistance to withstand temperatures from boiling to semi-retort heat treatment (90 to 110°C), has a small amount of gas emission from itself, adsorbs gas from the outside in contact, and suppresses changes in the odor of the contents.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

[0008] In each figure, for the sake of clarity, the size and ratio of the members may be changed or exaggerated in the description. In addition, for the sake of visibility, parts that are not necessary for the explanation and repeated reference numerals may be omitted. Although omitted in each figure, an adhesive layer can also be provided between each layer. Furthermore, if necessary, in order to strengthen the adhesive strength (adhesion strength) between each layer, physical surface treatments such as corona discharge treatment, ozone treatment, plasma treatment, glow discharge treatment, sandblasting treatment, etc., and chemical surface treatments such as oxidation treatment using chemical agents can be performed in advance on the laminated surfaces of each layer.

Modes for Carrying Out the Invention

[0009] The highly heat-resistant and low-odor gas adsorption sealing film of the present invention will be further described in detail below. Although it will be described with specific examples, the present invention is not limited thereto. In the present invention, the film and the sheet are treated as synonymous.

[0010] ≪Highly heat-resistant and low-odor gas adsorption sealing film≫ The highly heat-resistant and low-odor gas adsorption sealing film of the present invention contains a highly heat-resistant and low-odor resin having heat-sealability and a gas adsorbent, and thus has excellent heat-sealability. Even when exposed to temperatures from boiling to semi-retort heat treatment (90 to 110 °C), it has high heat resistance to withstand, small heat shrinkage, suppressed generation of a fish-skin appearance, a small amount of gas release (including elution) from itself, adsorbs gas from the outside in contact, and can suppress the change in the odor of the packaged contents caused by these gases.

[0011] The highly heat-resistant and low-odor gas adsorption sealing film may have a single-layer structure of one layer or a multilayer structure of two or more layers. For example, it may be composed of one layer of a gas adsorption layer containing a highly heat-resistant and low-odor resin and a gas adsorbent, it may be composed of two layers of a gas adsorption layer containing a highly heat-resistant and low-odor resin and a gas adsorbent and a heat-sealing layer containing a highly heat-resistant and low-odor resin, or it may have a three-layer structure in which two heat-sealing layers sandwich a gas adsorption layer.

[0012] In the resin contained in all the highly heat-resistant and low-odor gas adsorption sealing films, the content of the highly heat-resistant and low-odor resin is preferably 70% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, and still more preferably 90% by mass or more and 100% by mass or less. If it is less than the above range, the low gas release property of the highly heat-resistant and low-odor gas adsorption sealing film may become insufficient. If it is more than the above range, it is likely to be difficult to achieve a balance in terms of various physical properties and workability, and on the other hand, the low gas release property is not improved much.

[0013] And the content of the gas adsorbent is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.5% by mass or more and 28% by mass or less in the layer containing the gas adsorbent. If it is less than the above range, the gas adsorption effect may be insufficient, and if it is more than the above range, the film-forming property may deteriorate. Here, the layer containing the gas adsorbent refers to the entire high heat resistance and low odor gas adsorption sealant film when the high heat resistance and low odor gas adsorption sealant film is composed of only one layer, and in the case of a multilayer structure having a gas adsorption layer, a heat seal layer, etc., for example, it refers to the gas adsorption layer.

[0014] When the high heat resistance and low odor gas adsorption sealant film of the present invention has a multilayer structure having a gas adsorption layer, a heat seal layer, etc., in order to enhance the heat sealability and laminating property, it is preferable that at least one outermost layer of the high heat resistance and low odor gas adsorption sealant film is a heat seal layer, and it is more preferable that both outermost layers are heat seal layers. Also, the high heat resistance and low odor resin contained in the gas adsorption layer and the high heat resistance and low odor resin contained in the heat seal layer may be the same or different.

[0015] The high heat resistance and low odor gas adsorption sealant film can adjust the gas adsorption property and gas release property by adjusting the film thickness. The thickness of the high heat resistance and low odor gas adsorption sealant film is preferably 25 μm or more and 150 μm or less, more preferably 30 μm or more and 100 μm or less in order to have a good balance among heat sealability, gas adsorption property, and low gas release property. If it is thinner than the above range, the heat sealability and / or gas adsorption property may be insufficient, and if it is thicker than the above range, the low gas release property may be inferior.

[0016] And the high heat resistance and low odor gas adsorption sealant film can further contain a small amount of a slip agent, an antiblocking agent, an antioxidant, a solvent, and other additives. The high heat resistance and low odor gas adsorption sealant film of the present invention preferably contains an antioxidant in order to suppress the generation of release gas derived from resin deterioration in a high-temperature environment. Conversely, it is preferable to limit the use of additives that are likely to increase the gas emission amount at high temperatures.

[0017] (Gas to be adsorbed) In the present invention, the gas components to be adsorbed mainly include the gas components originally contained in the high heat resistance and low odor gas adsorption sealant film of the present invention, and the gas components generated by the decomposition of the resin in the high heat resistance and low odor gas adsorption sealant film due to heating such as heat sealing, boiling, semi-retort treatment, etc., or irradiation with UV or EB. Here, the gas components originally contained in the high heat resistance and low odor gas adsorption sealant film include the gas components contained in the raw materials constituting the high heat resistance and low odor gas adsorption sealant film, and the gas components generated by the heat history during the formation of the high heat resistance and low odor gas adsorption sealant film, etc. In particular, the gas components originally contained in the high heat resistance and low odor gas adsorption sealant film, the gas components contained in the raw materials constituting the high heat resistance and low odor gas adsorption sealant film, and the gas components generated by the heat history during the formation of the low gas emission gas adsorption sealant film, etc. are mentioned.

[0018] Specific examples of the gas to be adsorbed include organic substances with relatively low molecular weights. The organic substance is a gas component derived from the high heat resistance and low odor gas adsorption sealant film. As compounds of the gas component, those with 1 to 16 carbon atoms are numerous, and examples of the types include hydrocarbons, aldehydes, ketones, carboxylic acids, etc.

[0019] Specific examples of hydrocarbons include propane, propene, butane, isobutane, 2-methylbutane, butene, isobutene, 2-methylpentane, 3-ethylpentane, 2,2-dimethylpentane, 3,3-dimethylpentane, hexane, cyclohexane, 2-methylhexane, 3-methylhexane, 2,5-dimethylhexane, heptane, 2-methylheptane, 3-methylheptane, 3-ethylheptane, 2,2,4,6,6-pentamethylheptane, 3-ethyl-3-methylheptane, 3-methylheptene, octane, 2-methyloctane, 4-ethyloctane, nonane, 3-methylnonane, decane, dodecane, etc.

[0020] Specific examples of aldehydes include formaldehyde, acetaldehyde, 2-methylpropanal, 3-methylbutanal, etc.

[0021] Specific examples of ketones include acetone, MEK, MIBK, 3,3-dimethyl-2-butanone, etc.

[0022] Specific examples of carboxylic acids include acetic acid, isovaleric acid, 2-methylpropanoic acid, 2,2- dimethylpropanoic acid, etc.

[0023] Hydrocarbons, aldehydes, ketones, and carboxylic acids are derived from the thermal history of the high heat resistance and low odor gas adsorption sealant film.

[0024] [Gas adsorption layer] The gas adsorption layer is a layer containing a gas adsorbent and having high gas adsorption properties. In order to maintain low gas emission properties, it is preferably further contained a high heat resistance and low odor resin as a binder resin. However, within a range that does not significantly impair the gas adsorption properties and low gas emission properties, it can contain other resins and various additives such as antioxidants. In the high heat resistance and low odor gas adsorption sealant film, the gas adsorption layer may include one layer or two or more layers having the same or different compositions.

[0025] The thickness of the gas adsorption layer is preferably 5 μm or more and 80 μm or less, more preferably 7 μm or more and 75 μm or less, in order to exhibit good gas adsorption properties. If it is thinner than the above range, the gas adsorption property may be insufficient. Even if it is thicker than the above range, the gas adsorption property will not be improved so much, and the rigidity of the high heat resistance and low odor gas adsorption sealant film may become too strong and the workability may deteriorate.

[0026] [Heat seal layer] The heat seal layer is a layer containing a high heat resistance and low odor resin and has high heat sealability. In order to have high heat sealability, it is preferably free of a gas adsorbent. And, in order to achieve both high heat sealability and low gas emission properties, the heat sealable resin contained is preferably a high heat resistance and low odor resin. However, various additives such as a gas adsorbent, other resins, and an antioxidant can be contained within a range that does not significantly impair the heat sealability and low gas emission properties. The heat seal layer in the high heat resistance and low odor gas adsorption sealant film may include one layer or two or more layers with the same or different compositions.

[0027] The thickness of the heat seal layer is preferably 3 μm or more and 30 μm or less, more preferably 5 μm or more and 20 μm or less, in order to exhibit good heat sealability. If it is thinner than the above range, the heat sealability may be insufficient. Even if it is thicker than the above range, the heat sealability will not be improved so much, and the rigidity of the high heat resistance and low odor gas adsorption sealant film may become too weak and the workability may deteriorate.

[0028] [High heat resistance and low odor resin] A high heat resistance and low odor resin is a resin having high heat resistance and a small gas emission amount, and the gas emission amount varies depending on the shape and heat history of the resin. By incorporating a heat sealable high heat resistance and low odor resin into the high heat resistance and low odor gas adsorption sealant film, heat sealability can be imparted to the high heat resistance and low odor gas adsorption sealant film, the amount of gas released can be reduced, and the passage and release of gas can be suppressed.

[0029] The gas emission amount of the high heat-resistant and low-odor resin is highly correlated with the concentration of elutable total organic carbon (TOC = Total Organic Carbon) contained in the high heat-resistant and low-odor resin and eluted by boiling or semi-retort treatment. TOC indicates the concentration of the total amount of oxidizable organic substances (organic carbon substances) in water in terms of the concentration of carbon amount, and is used as one of the typical water quality indicators, and is standardized by JIS K0805 (Automatic Total Organic Carbon (TOC) Measuring Instrument), etc.

[0030] The concentration of elutable total organic carbon ( TOC) contained in the film made of the high heat-resistant and low-odor resin in the present invention is preferably 1.5 ppm or more and 250 ppm or less, and more preferably 5 ppm or more and 200 ppm or less. It is difficult to prepare those with less than the above range, and it is difficult to show a significant difference in practical effects. If it is more than the above range, the gas emission property of the high heat-resistant and low-odor resin may become insufficient.

[0031] Here, the reason for measuring the concentration of elutable TOC for the high heat-resistant and low-odor resin as a single raw material in the state of being formed into a film rather than in the state of raw material pellets, etc. is that when the high heat-resistant and low-odor resin is formed into a film for forming a low gas emission gas adsorption sealant layer, etc., various heat histories, etc. may be given, resulting in an increase in the elution amount of TOC.

[0032] The concentration of elutable total organic carbon (TOC) contained in the film made of the above high heat-resistant and low-odor resin can be measured as follows. For example, the film made of the high heat-resistant and low-odor resin in the present invention is placed in a gas sampling bag filled with distilled water as filling water, boiled to elute organic carbon substances, cooled and stored, and then the TOC concentration in the filling water is measured. Then, by subtracting the TOC concentration of the filling water before filling as a blank, the increase in the TOC concentration is calculated, and further, the concentration of elutable TOC contained in the film made of the high heat-resistant and low-odor resin can be calculated.

[0033] Specific conditions include a boiling temperature of 90°C to 100°C, a boiling time of 10 minutes to 60 minutes, a storage temperature of 25°C to 50°C, a storage period of 1 day to 4 weeks, and it is preferable to measure the TOC concentration of the filling water using a total organic carbon meter or HS-GC.

[0034] The density of the high heat-resistant and low-odor resin is preferably 0.920 g / cm 3 or more and 0.960 g / cm 3 or less, and more preferably 0.925 g / cm 3 or more and 0.955 g / cm 3 or less. If the density is within the above range, the gas emission amount can be reduced.

[0035] The MFR (melt flow rate) of the high heat-resistant and low-odor resin is preferably 0.2 g / 10 min or more and 10 g / 10 min or less, and more preferably 0.5 g / 10 min or more and 7 g / 10 min or less. If the MFR is within the above range, even when mixed with other resins or gas adsorbents, it can maintain a good MFR and exhibit good film-forming properties and adhesiveness.

[0036] As the high heat-resistant and low-odor resin, a polyethylene-based resin (low gas-emitting polyethylene-based resin) is preferable because it has excellent heat-sealing properties, is resistant to UV or EB irradiation and heating, and is difficult to decompose. The low gas-emitting polyethylene-based resin originally contains a small amount of gas that can be emitted, and is resistant to UV or EB irradiation and heating, and is difficult to decompose, so the gas emission amount can be reduced.

[0037] Specific examples of polyethylene species of the low gas emission polyethylene-based resin include, but are not limited to, low density polyethylene (LDPE), linear (linear) low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylic acid copolymer, ethylene-propylene copolymer, etc., which have been made to emit less gas, and mixtures of these resins.

[0038] Among the above, it is preferably one or a combination of two or more selected from the group consisting of HDPE, MDPE, LDPE and LLDPE. Also, LLDPE is preferably one or a combination of two or more selected from the group consisting of C4-LLDPE, C6-LLDPE, and C8-LLDPE, and C6-LLDP E is more preferred.

[0039] Here, C4-LLDPE is a linear low density polyethylene composed of a copolymer of ethylene and 1-butene, C6-LLDPE is a linear low density polyethylene composed of a copolymer of ethylene and 1-hexene and / or 4-methyl-1-pentene, and C8-LLDPE is a linear low density polyethylene composed of a copolymer of ethylene and 1-octene. Each molecular structure has a molecular structure in which side chains having 4, 6, and 8 carbon atoms derived from 1-butene, 1-hexene and / or 4-methyl-1-pentene, and 1-octene, respectively, are present in the main chain of LLDPE derived from ethylene.

[0040] In order to keep the amount of released gas contained in the resin low, for example, when manufacturing the resin, it is effective to reduce the amount of unreacted raw material residue, low molecular weight products, and by-products, or to remove the polymerization catalyst. Specifically, methods include improving the purity of the raw materials, precisely controlling conditions such as reaction temperature and pressure, removing unreacted raw materials, low molecular weight products, by-products, and polymerization catalysts by distillation or washing, and preventing oxidation by exposing to oxygen in the air while at a high temperature. As another method, when pelletizing or forming the manufactured resin into a film, it is possible to limit the use of additives that are likely to increase the amount of released gas and prevent oxidation at high temperatures. Specific additives include lubricants, antioxidants, antiblocking agents, solvents, and others.

[0041] [Gas adsorbent] In the present invention, as the gas adsorbent, it is preferable to contain one or a combination of two or more selected from the group consisting of hydrophobic zeolite, molecular sieve, metal-organic framework (MOF), and activated carbon.

[0042] (Hydrophobic zeolite) In the present invention, the hydrophobic zeolite used as the gas adsorbent preferably has an SiO2 / Al2O3 molar ratio of 2 / 1 to 10000 / 1, more preferably 30 / 1 to 2000 / 1. If the molar ratio is within the above range, it has an excellent balance between hydrophobicity and pore size and can exhibit good gas adsorption properties. The hydrophobic zeolite can be preferably used because the adsorption effect of gas components is maintained even when exposed to 230°C or higher. The hydrophobic zeolite may have any external shape such as spherical, rod-shaped, or elliptical, and may be in any form such as powder, lump, or granule. However, from the viewpoints of uniform dispersibility, kneading characteristics, film-forming properties, etc. when dispersed in the resin, the powder form is preferable.

[0043] In the present invention, the average particle size of the hydrophobic zeolite can be appropriately selected according to the application, and any average particle size can be selected. However, an average particle size of 0.01 μm or more and 30 μm or less is preferable, and an average particle size of 0.1 μm or more and 20 μm or less is more preferable. Here, the average particle size is a value measured by the dynamic light scattering method. When the average particle size is smaller than the above range, aggregation of the hydrophobic zeolite is likely to occur, and the dispersibility tends to decrease. Further, when the average particle size is larger than the above range, the film-forming property of the layer containing the hydrophobic zeolite tends to be poor, so it is difficult to add a large amount of the hydrophobic zeolite, and further, the surface area also decreases, so there is a possibility that a sufficient gas adsorption effect cannot be obtained.

[0044] Since the hydrophobic zeolite is hydrophobic, it is difficult to adsorb highly polar water molecules and the like. On the contrary, it has a high affinity for low-polarity organic gases and also has a high affinity for other low-polarity gas components, hydrophobic gases, and lipophilic gases ( including solvent-based gases), and is likely to adsorb these. That is, it has an excellent function of adsorbing gas components having no functional group. Further, when alkali metals or alkaline earth metals such as Ca, Na, and K are present on the zeolite surface, the zeolite surface shows basicity and is likely to adsorb acidic gases by a neutralization reaction.

[0045] (Molecular sieve) Molecular sieve is a kind of hydrophilic zeolite and adsorbs highly polar molecules in porous pores. In particular, it strongly adsorbs water (water vapor) molecules. Molecular sieves are designated as 3A, 4A, 5A, and 13X depending on the type of raw material zeolite. The numbers represent the approximate diameter of the pores (angstroms), and the capital letters represent the type of zeolite. A represents LTA-type zeolite, and X represents FAU-type zeolite. 3A is suitable for adsorbing large molecules such as acetonitrile and ethanol, 5A is suitable for adsorbing aromatic compounds, etc., and 13X is suitable for adsorbing large molecules such as long-chain tertiary amines.

[0046] (Metal-organic framework (MOF)) For metal-organic frameworks (MOF), salts composed of metal ions and organic ligands are preferably used. Compared with common activated carbon and zeolites, metal-organic frameworks can have a porous structure with smaller pore diameters and larger specific surface areas. Specific examples of metal-organic frameworks include aluminum fumarate, zirconium fumarate, copper trimesate, aluminum trimesate, zirconium trimesate, iron trimesate, aluminum terephthalate, zirconium terephthalate, zinc 2-methylimidazole, magnesium formate, zinc benzene-1,3,5-tricarboxylate, zinc 2,6-naphthalene-dicarboxylate, aluminum aminobenzene-1,4-dicarboxylate, magnesium 2,5-dioxidebenzene-1,4-dicarboxylate, magnesium 4,4-dioxidebiphenyl-3,3-dicarboxylate, etc. One or a combination of two or more selected from these groups can be used.

[0047] The pore diameter of the metal-organic framework is preferably 0.3 nm or more and 3.0 nm, more preferably 0.3 nm or more and 2.0 nm or less. For example, the pore diameters of zinc 2-methylimidazole salt are 1.1 nm and 0.6 nm, copper trimesate are 0.90 nm or 0.3 nm and 0.5 nm, aluminum terephthalate are 0.8 nm and 0.5 nm, aluminum fumarate are 1.1 nm and 0.5 nm, aluminum trimesate are 0.7 nm and 0.6 nm, zirconium trimesate are 0.46 nm, 1.15 nm, and 1.8 nm, magnesium formate are 0.3 nm and 0.4 nm, and iron trimesate are 2.5 nm and 2.9 nm.

[0048] The specific surface area of the metal-organic framework can be expressed by the BET specific surface area or the Langmuir specific surface area. In the case of the BET specific surface area, it is preferably 400 m 2 / g or more and 4000 m 2 / g or less, more preferably 900 m 2 / g or more and 2100 m 2 / g or less. In the case of the Langmuir specific surface area, it is preferably 500 m 2 / g or more and 5000 m 2 / g or less, more preferably 1200 m 2 / g or more and 2400 m 2 / g or less.

[0049] The BET specific surface area is, for example, 1350 m 2 / g for zinc 2-methylimidazole, 1500 m 2 / g for copper trimesate, 950 m 2 / g for aluminum terephthalate, 1000 m 2 / g for aluminum fumarate, 1100 m 2 / g for zirconium trimesate, 2060 m 2 / g for magnesium formate, 400 m 2 / g for zinc benzene-1,3,5-tricarboxylate, and there are those with 3600 m 2 / g. The Langmuir specific surface area is, for example, 1800 m 2 / g for zinc 2-methylimidazole, 2000 m 2 / g for copper trimesate, 1500 m 2 / g for aluminum terephthalate, and 1200 m 2 / g for aluminum fumarate, 1500 m 2 / g for zirconium trimesate, 2390 m 2 / g for magnesium formate, 500 m 2 / g for zinc benzene-1,3,5-tricarboxylate, and there are those with 5000 m 2 / g.

[0050] The above metal-organic structure can absorb a gas in an amount corresponding to its pore diameter and specific surface area. For example, zinc 2-methylimidazole salt can absorb lower hydrocarbons and carbon dioxide, copper trimesate can absorb lower hydrocarbons (especially methane) and carbon dioxide, aluminum terephthalate is excellent in the ability to absorb methane, water vapor, and carbon dioxide, aluminum fumarate and zirconium trimesate are excellent in the ability to absorb water vapor, and aluminum trimesate is excellent in the ability to absorb lower hydrocarbons (especially methane) and water vapor.

[0051] In the present invention, among the above metal-organic structures, it is preferable to use one or a combination of two or more selected from the group consisting of zinc 2-methylimidazole salt, copper trimesate, and aluminum terephthalate.

[0052] (Activated carbon) Activated carbon is a porous substance mainly composed of carbon and containing oxygen, hydrogen, calcium, etc., and is subjected to chemical or physical treatment. Due to its porous nature, it has a large surface area per unit volume and thus has the property of adsorbing many substances. Since the surface of activated carbon is non-polar, it has a low adsorbing power for polar molecules and is likely to selectively adsorb particulate organic substances smaller than the pores of activated carbon.

[0053] (Improving dispersibility by masterbatch of gas adsorbent) The gas adsorbent may be directly mixed with other constituent components of the high heat-resistant and low-odor gas adsorption sealant film and melt-kneaded. However, after mixing the gas adsorbent with a thermoplastic resin at a high concentration and then melt-kneading (melt-blending) to prepare a masterbatch, this is mixed with other constituent components of the high heat-resistant and low-odor gas adsorption sealant film at a ratio corresponding to the target content rate and melt-kneaded. By the so-called masterbatch method, it is preferable to enhance the dispersibility of the gas adsorbent in the high heat-resistant and low-odor gas adsorption sealant film. By adopting the masterbatch method, even when a gas adsorbent that is likely to cause aggregation is used, the gas adsorbent can be efficiently and homogeneously dispersed in the high heat-resistant and low-odor gas adsorption sealant film.

[0054] The mass ratio of the gas adsorbent to the thermoplastic resin in the masterbatch is not particularly limited, but a ratio of 3 / 97 or more and 50 / 50 or less is preferable, and a ratio of 5 / 95 or more and 40 / 60 or less is more preferable. As a method for kneading the gas adsorbent and the thermoplastic resin, various kneading methods can be applied. The thermoplastic resin used in the masterbatch can be used in a type and content within a range that does not significantly affect the heat sealability, film-forming property, gas adsorption property, and low gas emission property of the entire high heat resistance low odor gas adsorption sealant film. However, a resin having high compatibility with other resins such as the heat sealable resin and the high heat resistance low odor resin contained in the high heat resistance low odor gas adsorption sealant film and having heat sealability equivalent to these is preferable, and it may be the same as or different from these. For example, it may be a high heat resistance low odor resin.

[0055] Specific examples of the thermoplastic resin used in the masterbatch include, for example, polyolefin resins such as general-purpose polyethylene, polypropylene, methylpentene polymer, and acid-modified polyolefin resins, and mixtures of these resins, etc., but are not limited to these resins, and the type of thermoplastic resin can be selected according to the purpose.

[0056] The MFR (melt flow rate) of the thermoplastic resin used in the masterbatch is preferably 0.2 g / 10 min or more and 10 g / 10 min or less. If the MFR is within this range, melt-kneading with the gas adsorbent is easy, the gas adsorbent is easily dispersed in the high heat resistance low odor gas adsorption sealant film, and the film-forming property of the high heat resistance low odor gas adsorption sealant film is also easily maintained.

[0057] (Method for producing a high heat resistance low odor gas adsorption sealant film) For example, a gas adsorption layer resin composition for a gas adsorption layer and a high heat resistance low odor resin for a heat seal layer are each prepared and prepared, and a high heat resistance low odor gas adsorption sealant film having the following layer structure can be obtained by an inflation method. Layer structure: Heat-sealing layer 1 / Gas adsorption layer / Heat-sealing layer 2 Alternatively, a gas adsorption layer resin composition for the gas adsorption layer and a highly heat-resistant and low-odor resin for the heat-sealing layer may be laminated on a release film by extrusion or co-extrusion using an extrusion coating method, and the release film may be removed. In the case of the extrusion coating method, lamination may be performed via an adhesive layer as necessary.

[0058] <Measurement of heat resistance of highly heat-resistant and low-odor gas adsorption sealant film> The highly heat-resistant and low-odor gas adsorption sealant film of the present invention is, for example, cut into 10 cm × 10 cm, and when boiled or heated at a temperature of 90 to 110°C for 10 to 60 minutes, the heat shrinkage rate can be 0% or more and 10% or less, and the occurrence of a slippery skin-like change on the surface can be suppressed. The heat shrinkage rate is the rate of change in length, and may be, for example, the average value of the heat shrinkage rates of the lengths of each side. In the present invention, heat resistance not only simply refers to little heat deformation and thermal decomposition at high temperatures, but also includes little release of gas components originally contained in the resin and maintenance of gas adsorption properties. For example, even when a package containing contents produced using a highly heat-resistant and low-odor gas adsorption sealant film is subjected to heat treatment such as high-temperature boiling treatment at 90°C to 100°C or semi-retort treatment at 100°C to 110°C, the generation of decomposition product odor can be suppressed, and a small amount of the generated decomposition product odor and the oxide odor of the contents can be adsorbed, thereby suppressing the change in the odor of the contents.

[0059] <Measurement and calculation of the eluted TOC concentration contained in the highly heat-resistant and low-odor resin film and the highly heat-resistant and low-odor gas adsorption sealant film> The concentration of eluted total organic carbon (TOC) contained in the above-mentioned highly heat-resistant and low-odor resin film and highly heat-resistant and low-odor gas adsorption sealant film can be measured and calculated as follows. The test piece film is described as a general term for the highly heat-resistant and low-odor resin film and the highly heat-resistant and low-odor gas adsorption sealant film. First, place the test piece film in the gas sampling bag, fill it with distilled water as the filling water, and seal it. Then, boil to elute the organic carbon substances, cool it to room temperature (about 35 °C), and let it stand for a certain period of time. After that, measure the TOC concentration in the filling water. Next, subtract the TOC concentration of the filling water before filling as a blank to calculate the increase in the TOC concentration, and calculate the elutable TOC concentration contained in the test piece film. As the gas sampling bag, SMART BAG manufactured by GL Sciences Inc. etc. can be used, and as the filling water, distilled water for high performance liquid chromatography can be used. And the TOC concentration of the filling water can be measured by a total organic carbon meter, HS-GC, for example, a TOC-L total organic carbon meter (manufactured by Shimadzu Corporation etc.).

[0060] Specific conditions are as follows: the boiling temperature is 90 °C to 100 °C, the boiling time is 10 minutes to 60 minutes , the temperature during storage is 25 °C to 50 °C, the storage period is 1 day to 4 weeks. When the test piece film is a resin film made of a high heat resistance and low odor resin, the boiling conditions are 90 °C for 30 minutes, and the storage conditions are 35 °C for 2 weeks, which are preferable. When the test piece film is a high heat resistance and low odor gas adsorption sealant film, the boiling conditions are 90 °C for 30 minutes, and the storage conditions are room temperature (35 °C) for 2 weeks, which are preferable.

[0061] The following shows an example of calculating the concentration C of the elutable TOC contained in the test piece film from the increased concentration of TOC in the filling water. Weight of filling water (distilled water): W1 = 1000 [g] Test piece film Density: S [g / cm 3 Size: 15 cm × 44 cm × 50 μm thick, 2 sheets Weight: W2 = 15 × 44 × 50 × 10 -4 × 2 × S = 6.6 × S [g] Contained elutable TOC concentration: C [ppm] Increase in TOC concentration in filling water: X [ppm]​ Then, Total weight of elutable TOC contained in the test piece film = C × W2 [g] Since this elutes into W1 [g] of water, X = C × W2 / W1 = C × 6.6 × S × 10 -3 [ppm] The relationship is as follows, and the elutable TOC concentration C contained in the test piece film is calculated from the following formula. C = X / (6.6 × S × 10 -3 ) [ppm] For example, when the density S of the test piece film is 1.00 [g / cm 3 and the increase in the TOC concentration of the filling water X is 0.01 [ppm], C = 0.01 / (6.6 × 1.00 × 10 -3 ) = 1.51 [ppm] It is calculated as follows.

[0062] The elutable TOC concentration contained in the high heat-resistant low odor gas adsorption sealant film measured under the above conditions is preferably 0.01 ppm or more and 1.5 ppm or less, and more preferably 0.02 ppm or more and 1.2 ppm or less. It is difficult to produce a product with a lower concentration than the above range, and it is difficult to show a significant difference in practical effects. If it is more than the above range, the low odor property of the high heat-resistant low odor gas adsorption sealant film may become insufficient. From the viewpoint of achieving both cost and performance, it is preferably within the above range.

Example

[0063] Details of the raw materials used in the examples are as follows. [High heat-resistant low odor resin] · High heat-resistant low odor resin 1: Manufactured by Prime Polymer Co., Ltd., Ultrex 3520L. C6-LLDPE, density 0.931 g / cm 3 , MFR 2.1 g / 10 min. Elutable TOC concentration contained in the resin film 42.3 ppm. · High heat-resistant low odor resin 2: Manufactured by Prime Polymer Co., Ltd., Ultrex 4020L. C6-LLDPE, density 0.937 g / cm 3, MFR 2.3 g / 10 min. The eluted TOC concentration contained in the resin film is 32.5 ppm. · High heat-resistant and low odor resin 3: High-Zex 3300F manufactured by Prime Polymer Co., Ltd. HDPE, density 0.949 g / cm 3 , MFR 1.1 g / 10 min. The eluted TOC concentration contained in the resin film is 24.4 ppm.

[0064] [General-purpose polyethylene] · General-purpose polyethylene 1: Evolue SP4020 manufactured by Prime Polymer Co., Ltd. C6-LLDPE, density 0.937 g / cm 3 , MFR 1.7 g / 10 min. The TOC concentration of the extracted water is 2 .85 ppm, and the eluted TOC concentration contained in the resin film is 461 ppm. · General-purpose polyethylene 2: Evolue SP1520 manufactured by Prime Polymer Co., Ltd. C6-LLDPE, density 0.913 g / cm 3 , MFR 2.0 g / 10 min. The TOC concentration of the resin-extracted water is 3.05 ppm, and the eluted TOC concentration contained in the resin film is 506 ppm.

[0065] [Gas adsorbent] · Hydrophobic zeolite 1: Hydrophobic zeolite manufactured by Mizusawa Chemical Industry Co., Ltd., Mizukaseb EX-122. SiO2 / AL2O3 molar ratio = 32 / 1, average particle diameter 2.5 - 5.5 μm. · Hydrophobic zeolite 2: Hydrophobic zeolite manufactured by Mizusawa Chemical Industry Co., Ltd., Siltone MT400. SiO2 / AL2O3 molar ratio = 400 / 1, average particle diameter 5 - 7 μm. · Hydrophobic zeolite 3: Hydrophobic zeolite manufactured by Mizusawa Chemical Industry Co., Ltd., Siltone MT-2000. SiO2 / AL2O3 molar ratio = 2000 / 1, average particle diameter 0.8 μm.

[0066] [Preparation of masterbatch] The masterbatch used for the gas adsorption layer was prepared as follows.

[0067] (Preparation of masterbatch 1) High heat-resistant and low-odor resin 1 and hydrophobic zeolite 1 were melt-blended at the following ratio to obtain masterbatch 1 (MB1). High heat-resistant and low-odor resin 1: 70 parts by mass Hydrophobic zeolite 1: 30 parts by mass

[0068] [Adjustment of masterbatches 2 to 5] According to the formulation in Table 1, each raw material was melt-blended in the same manner as masterbatch 1 to obtain masterbatches 2 to 5 (MB2 to 5).

[0069]

Table 1

[0070] <Example 1> [Preparation of gas adsorption layer resin composition] MB1 and high heat-resistant and low-odor resin 1 were dry-blended at the following ratio to obtain gas adsorption layer resin composition 1 for use in the gas adsorption layer. MB1: 5.6 parts by mass High heat-resistant and low-odor resin 1: 94.4 parts by mass

[0071] [Production of high heat-resistant and low-odor gas adsorption sealant film] Using the gas adsorption layer resin composition 1 obtained above and high heat-resistant and low-odor resin 1, a high heat-resistant and low-odor gas adsorption sealant film 1 with the following layer structure was obtained by the inflation method. Using the obtained high heat-resistant and low-odor gas adsorption sealant film 1, film formability, heat shrinkability, TOC elution amount, and odor functionality were evaluated. Layer structure of high heat-resistant and low-odor gas adsorption sealant film 1: Heat seal layer 1 / Gas adsorption layer / Heat seal layer 2 = High heat-resistant and low-species resin 1 (10 μm thick) / Gas adsorption layer resin composition 1 (30 μm thick) / High heat-resistant and low-odor resin 1 (10 μm thick)

[0072] <Examples 2 to 9, Comparative Examples 1 to 4> In accordance with the layer structure of the entire film shown in Tables 2 to 4, a gas adsorption layer resin composition was prepared. Using the gas adsorption layer resin composition and / or resin, a highly heat-resistant and low-odor gas adsorption sealant film was obtained by the inflation method in the same manner as in Example 1 and evaluated in the same way.

[0073]

Table 2

[0074]

Table 3

[0075]

Table 4

[0076] <Evaluation method> [Film formability] The appearance of the highly heat-resistant and low-odor gas adsorption sealant film was observed and evaluated sensorially. The evaluation criteria are as follows. ○: Film formation is possible without wrinkles or bumps. ×: Many wrinkles and bumps occur, making film formation difficult.

[0077] [Heat sealability] The highly heat-resistant and low-odor gas adsorption sealant film was cut into pieces of 10 cm × 10 cm. One side was adhered to a PET film (PET film manufactured by Toyobo Co., Ltd., Esterpet T4102, thickness 12 μm) by dry lamination adhesion via a dry lamination adhesive (manufactured by Rock Paint Co., Ltd., Adlock RU77T / H7, polyester-based adhesive) to obtain a laminate. Then, two pieces of the laminate prepared above were overlapped with the heat-sealing surfaces facing each other, and a 1 cm × 10 cm area was heat-sealed under the following conditions using a heat-sealing tester (manufactured by Tester Sangyo Co., Ltd.: TP-701-A). The ends were not heat-sealed and were not adhered, and a test piece with a peel strength in a forked state was prepared. This test piece was cut into strips 15 mm wide, and each forked end was attached to a tensile testing machine to measure the peel strength (N / 15 mm) under the following conditions, and the pass / fail judgment was made according to the following pass / fail criteria. Heat seal conditions Temperature: 160 °C Pressure: 1 kgf / cm 2 Time: 1 second Test conditions Test speed: 300 mm / min Load range: 50 N Pass / fail criteria ○: 30 N / 15 mm or more, passing. ×: Less than 30 N / 15 mm, failing.

[0078] [Heat shrinkage state after boiling] The highly heat-resistant and low-odor gas adsorption sealant film cut into 10 cm × 10 cm was boiled in hot water at 90 to 100 °C for 10 minutes, and the average value of the shrinkage rate of each side length after boiling was calculated, and the pass / fail judgment was made according to the following criteria. 〇: Heat shrinkage rate of 10% or less. Passing. ×: Heat shrinkage rate greater than 10% or the film is welded and cannot be measured. Failing.

[0079] [Presence or absence of orange peel after boiling] The highly heat-resistant and low-odor gas adsorption sealant film cut into 10 cm × 10 cm was boiled in hot water at 90 to 100 °C for 10 minutes, the appearance was observed visually, and the presence or absence of orange peel generation was confirmed. 〇: No orange peel, passing. ×: Presence of orange peel, failing

[0080] [Elutable TOC concentration] A gas sampling bag (GL Sciences Inc., SMART BAG) was filled and sealed with a highly heat-resistant and low-odor gas adsorption sealant film of the following size and filling water, boiled at 90 °C for 30 minutes, cooled to room temperature, and after storing at 35 °C for 2 weeks, the TOC concentration of the filling water was measured to obtain the increased concentration of the TOC concentration. High heat-resistant and low-odor gas adsorption sealant film Size: 15 cm × 44 cm × 50 μm thick × 2 sheets. Filling water: Distilled water for high performance liquid chromatography manufactured by Junsei Chemical Co., Ltd. 1000 g. TOC concentration measuring instrument: TOC-L total organic carbon meter manufactured by Shimadzu Corporation. Next, from the increased concentration of TOC in the filling water obtained above, the concentration of eluted TOC contained in the high heat-resistant and low-odor gas adsorption sealant film was calculated by the following formula. C = X × W1 / W2 = X × W1 / (6.6 × S) C: Concentration of eluted TOC contained in the high heat-resistant and low-odor gas adsorption sealant film [ppm] X: Increased concentration of TOC in the filling water [ppm] W1: Filling water weight = 1000 [g] W2: High heat-resistant and low-odor gas adsorption sealant film weight = 15 × 44 × 50 × 10 -4 × 2 × S = 6.6 × S [g] S: Density of the high heat-resistant and low-odor gas adsorption sealant film [g / cm 3

[0081] [Odor sensory evaluation] Two sheets of high heat-resistant and low-odor gas adsorption sealant film cut to 11 cm × 15 cm and 100 ml of water (Japanese natural water, Suntory) as filling water were filled into a pouch (outer dimensions: 13 cm × 17 cm) made with a gas sampling bag (GL Sciences, SMART BAG) to prepare a packaged liquid filling, boiled at 90°C for 30 minutes, and then stored at room temperature for one week. After that, a sensory evaluation of the odor of the filling water was carried out. The evaluation criteria are as follows. 1: Strong odor 2: Odor slightly reduced 3: Odor significantly reduced 4: Equivalent to natural water before filling

[0082] [Summary of results] The high heat-resistant and low-odor gas adsorption sealant film of all examples showed excellent film-forming properties, heat-sealing properties, low heat shrinkage after boiling, appearance after boiling, elution TOC concentration, and odor functionality. However, the sealant films of Comparative Examples 1, 2, and 3 using general-purpose resins showed inferior results in any of the low heat shrinkage after boiling, appearance after boiling, elution TOC concentration, and odor functionality. Also, the sealant film of Comparative Example 4 with an excessive gas adsorbent content showed inferior film-forming properties and heat-sealing properties.

Explanation of symbols

[0083] 1 High heat-resistant and low-odor gas adsorption sealant film 4a Gas adsorption layer 4b Gas adsorbent 4c Heat-sealing layer

Claims

1. A highly heat-resistant and low-odor gas adsorption sealing film, which contains a highly heat-resistant and low-odor resin having heat-sealability and a gas adsorbent, and adsorbs gases generated from itself and external gases. The gas is one or a combination of two or more selected from the group consisting of hydrocarbons, aldehydes, ketones, and carboxylic acids. The high heat-resistant and low-odor resin has a density of 0.920 g / cm 3 or more and 0.960 g / cm 3 or less, and The gas adsorbent is a hydrophobic zeolite. The content of the highly heat-resistant and low-odor resin in the resin contained in the entire highly heat-resistant and low-odor gas adsorption sealing film is 70% by mass or more and 100% by mass or less. The content of the gas adsorbent is 0.1% by mass or more and less than 27.50% by mass in the layer containing the gas adsorbent. The concentration of eluted total organic carbon (TOC) contained in the film made of the highly heat-resistant and low-odor resin is 24.4 ppm or more and 42.3 ppm or less, and elutes by boiling treatment at 90 to 110 °C for 30 minutes and standing storage at 35 °C. When boiled at a temperature of 90 °C or more and 100 °C or less for 10 minutes or more and 60 minutes or less, the heat shrinkage rate is 0% or more and 10% or less, and there is no change like a slippery skin on the surface. The highly heat-resistant and low-odor gas adsorption sealing film according to claim 10.

2. The highly heat-resistant and low-odor gas adsorption sealing film according to claim 1, wherein the highly heat-resistant and low-odor resin is a polyethylene-based resin.

3. The highly heat-resistant and low-odor gas adsorption sealing film according to claim 1, wherein the highly heat-resistant and low-odor resin is one or a combination of two or more selected from the group consisting of high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene.

4. The highly heat-resistant and low-odor gas adsorption sealing film has a gas adsorption layer and a heat-sealing layer. The gas adsorption layer is a layer containing the highly heat-resistant and low-odor resin and the gas adsorbent. The heat-sealing layer is a layer containing the highly heat-resistant and low-odor resin and having heat-sealability. At least one outermost layer on one side of the highly heat-resistant and low-odor gas adsorption sealing film is a heat-sealing layer. The highly heat-resistant and low-odor resin contained in the gas adsorption layer and the highly heat-resistant and low-odor resin contained in the heat-sealing layer are the same or different. The highly heat-resistant and low-odor gas adsorption sealing film according to any one of claims 1 to 3.

5. ​ A high heat-resistant and low odor gas adsorption sealing film for retort sterilization or semi-retort sterilization, using the high heat-resistant and low odor gas adsorption sealing film according to any one of claims 1 to 4.

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