Anti-fogging multilayer film, laminate using the same, and packaging material

Abstract

The present invention provides a multilayer film comprising a sealing layer (A) and a resin layer (B) adjacent to the sealing layer (A), wherein the sealing layer (A) comprises a polyester resin (a), an antifogging agent, and polyalkylene glycol, and the resin layer (B) comprises an acid-modified polyolefin and a polyester resin (b); a laminate having the multilayer film; a packaging material using the laminate; the packaging material which is a lid material for a food packaging container; and a food packaging container which uses the packaging material as a lid material, wherein the portion of the food packaging container that adheres to the lid material contains a polyester resin.

Description

[Technical Field]

[0001] The present invention relates to a multilayer film that is suitable for use as a lid material for food packaging containers, possessing both anti-fogging properties and easy-opening properties, and a laminate using the same. [Background technology]

[0002] Traditionally, polyester containers, which offer excellent transparency and recyclability, have been widely used as packaging for chilled foods such as pre-cut vegetables and fruits. The lids of these containers are required to be anti-fogging in order to improve the visibility of the contents. This is because if moisture evaporates from the chilled food inside the container, fogging occurs on the inner surface of the packaging material, making it difficult to see the contents, which reduces the value of the product and thus fails to meet consumers' demands for food safety and security. Furthermore, while it is essential for the lid material of the container to have a secure seal until the contents are removed, in the context of the trend toward universal design, ease of opening for consumers, such as easy-to-open designs, is considered important as a consideration for socially vulnerable groups (the elderly, infants, people with disabilities, etc.).

[0003] Currently, methods for imparting anti-fogging properties to packaging materials include a method in which a resin is formed into a film and then an anti-fogging agent is applied to the surface that comes into contact with the contents (see, for example, Patent Document 1), and a method in which an anti-fogging agent is kneaded into the resin used for the packaging material, which is then formed into a film and subsequently secondarily molded for various packaging materials.

[0004] In methods where a coating liquid containing an anti-fogging agent is applied to the film surface, the process requires both the application step of the anti-fogging agent and the drying step of the coating film, resulting in low production efficiency. Furthermore, the anti-fogging agent on the coated surface is washed away by the evaporation of moisture from the contents, leading to a decrease in the durability of the anti-fogging effect.

[0005] Furthermore, when incorporating an antifogging agent into a resin, such as in single-layer films or multi-layer films where the antifogging agent is incorporated into all layers, printing on the surface or lamination with other base films can cause the antifogging agent to bleed out onto the surface, reacting with the printing ink or adhesive and potentially leading to peeling of the printed surface or poor adhesion. On the other hand, in methods of incorporating an antifogging agent into the sealing layer of a multi-layer film (see, for example, Patent Document 2), the antifogging agent has a tendency to migrate within the multi-layer film, resulting in inconsistent antifogging effects and concerns about the durability of the effect. Additionally, the migration of the antifogging agent from the layer containing the antifogging agent to adjacent layers can reduce interlayer adhesion and potentially worsen film breakability.

[0006] In response to these challenges, the applicants conducted studies and found that a film having an anti-fogging agent in the heat-seal layer, with adjusted free volume pore size and rigidity in the heat-seal layer, can suppress deterioration of film breakage over time, thus completing the invention described in Patent Document 3.

[0007] On the other hand, it is common practice to laminate a multilayer film containing an anti-fogging agent with a base film. The laminated film obtained by lamination is usually subjected to an aging treatment by storing the rolled film at 30-60°C for 1 to 4 days to accelerate the curing of adhesives and obtain high adhesive strength. However, when aging is performed in this rolled film state, the anti-fogging agent on the surface of the multilayer film may migrate to the base film surface it is in contact with, sometimes resulting in a deterioration of its anti-fogging properties. This invention was developed to create an anti-fog film that has excellent film breakability and further suppresses the deterioration of anti-fog properties due to aging treatment. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2004-025825 [Patent Document 2] Japanese Patent Application Laid-Open No. 2019-171792 [Patent Document 3 WO2023 / 063091 [Summary of the Invention [Problems to be Solved by the Invention

[0009] In view of the above circumstances, an object of the present invention is to provide a multilayer film suitable for uses such as a lid material of a packaging container, which has good film breakage properties and excellent peelability, suppresses deterioration due to aging in terms of anti-fogging properties that prevent fogging caused by water vapor from the contents, and has good seal strength, a laminate obtained by laminating this multilayer film on a base film, and a packaging material using the same. [Means for Solving the Problems

[0010] As a result of intensive studies to solve such problems, the present inventor has found that a multilayer film including a seal layer (A) and a resin layer (B) adjacent to the seal layer (A), wherein the seal layer (A) contains a polyester resin (a), an anti-fogging agent, and a polyalkylene glycol, and the resin layer (B) contains an acid-modified polyolefin and a polyester resin (b) can solve the above problems, and completed the present invention.

[0011] That is, the present invention provides the following multilayer films, packaging materials, and food packaging containers. (1) A multilayer film including a seal layer (A) and a resin layer (B) adjacent to the seal layer (A), wherein the seal layer (A) contains a polyester resin (a), an anti-fogging agent, and a polyalkylene glycol, and the resin layer (B) contains an acid-modified polyolefin and a polyester resin (b). (2) The multilayer film according to (l), wherein the polyalkylene glycol has a freezing point of 40°C or higher. (3) The multilayer film according to (1), wherein the sealing layer (A) comprises polyester resin (a1) and polyester resin (a2) as polyester resin (a), the glass transition temperature of polyester resin (a1) is 60 to 140°C, and the glass transition temperature of polyester resin (a2) is 45°C or less. (4) The multilayer film according to (1), wherein the glass transition temperature of the polyester resin (b) is 45°C or less. (5) The multilayer film according to (1), wherein the content of polyalkylene glycol in the sealing layer (A) is 0.1 to 5.0% by mass. (6) The multilayer film according to (1), wherein the mass ratio of the acid-modified polyolefin to the polyester resin (b) in the resin layer (B) is 45:55 to 95:5. (7) The multilayer film according to (1), wherein the multilayer film further includes a laminate layer. (8) A laminate having a multilayer film as described in any of (1) to (7). (9)(8) Packaging material using the laminate described above. (10) The packaging material described in (9), which is a lid material for a food packaging container. A food packaging container having the packaging material described in (11)(10) as a lid material, wherein the portion of the food packaging container that adheres to the lid material contains a polyester resin. [Effects of the Invention]

[0012] The multilayer film and laminate using the same of the present invention exhibit excellent easy-open properties when sealed as a lid material for polyester packaging containers or when sealed in a bag shape, as the sealing layer (A) firmly heat-fusible to the polyester packaging container or polyester film, preventing film tearing upon opening. Furthermore, since the deterioration of anti-fogging properties is suppressed even after aging treatment, it can be suitably used as a packaging material for chilled foods such as fresh produce and prepared foods. [Modes for carrying out the invention]

[0013] The following describes in detail the various components constituting the multilayer film of the present invention and the laminate formed using it.

[0014] <Seal layer (A)> The multilayer film of the present invention comprises a sealing layer (A) containing a polyester resin (a), an antifogging agent, and a polyalkylene glycol. The sealing layer (A) constitutes the surface layer of one side of the multilayer film and laminate of the present invention, and is a layer that seals the sealing surface of the polyester packaging container. It also has an anti-fogging function and can turn water droplets adhering to the inner surface of the multilayer film and laminate into a water film, thereby reducing fogging caused by water vapor from the contents and improving the visibility of the contents.

[0015] <Anti-fogging agent> The sealing layer (A) used in this invention contains an anti-fogging agent. The anti-fogging agent is not particularly limited as long as it is generally known to impart anti-fogging properties. For example, anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, etc., can be used. Among these, the use of nonionic surfactants is preferred.

[0016] Specifically, the nonionic surfactants mentioned above include sorbitan-based surfactants such as sorbitan monostearate, sorbitan distearate, sorbitan monopalmitate, sorbitan dipalmitate, sorbitan monobehenate, sorbitan dibehenate, sorbitan monolaurate, and sorbitan dilaurate; glycerin-based surfactants such as glycerin monolaurate, glycerin dilaurate, diglycerin monopalmitate, diglycerin dipalmitate, glycerin monostearate, glycerin distearate, diglycerin monostearate, diglycerin distearate, diglycerin monolaurate, and diglycerin dilaurate; polyethylene glycol monostearate, polyethylene Examples include polyethylene glycol-based surfactants such as glycol monopalmitate; trimethylolpropane-based surfactants such as trimethylolpropane monostearate; diethanolalkylamine-based and diethanolalkylamide-based surfactants such as lauryldiethanolamine, oleyldiethanolamine, stearyldiethanolamine, lauryldiethanolamide, oleyldiethanolamide, and stearyldiethanolamide; pentaerythritol-based surfactants such as pentaerythritol monopalmitate; and polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan distearate, and mono and distearates of sorbitan-diglycerin condensates. These can be used individually or in combination of two or more. Glycerin-based surfactants are particularly preferred.

[0017] The lower limit of the amount of antifogging agent used in the seal layer (A) in the present invention is preferably 0.5% by mass or more, and more preferably 1.0% by mass or more, relative to the total mass of the layer. Using the antifogging agent within this range makes it easier to exhibit antifogging properties. The upper limit of the amount of antifogging agent used is preferably 7.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 4.0% by mass or less, relative to the total mass of the seal layer (A). Using the antifogging agent within this range makes it less likely for the antifogging agent to migrate excessively to the layer in contact with the seal layer (A), and suppresses a decrease in interlayer strength. In other words, the amount of antifogging agent in the seal layer (A) is preferably 1.0 to 7.0% by mass, more preferably 1.0 to 6.0% by mass, even more preferably 1.0 to 5.0% by mass, and particularly preferably 1.0 to 4.0% by mass.

[0018] <Polyalkylene glycol> The sealing layer (A) used in the present invention contains polyalkylene glycol. Examples of the polyalkylene glycols mentioned above include polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene glycol, polypentamethylene glycol, polyhexamethylene glycol, polyoctamethylene glycol, and block copolymers (sometimes referred to as PEG-PPG copolymers) having polyoxyethylene glycol (polyethylene glycol) units and polyoxypropylene glycol (polypropylene glycol) units in their molecules. Among these, polyethylene glycol, polypropylene glycol, and PEG-PPG copolymers are preferred, polyethylene glycol and PEG-PPG copolymers are more preferred, and polyethylene glycol is even more preferred.

[0019] The polyethylene glycol (sometimes referred to as PEG) used above can, for example, have a number-average molecular weight of approximately 1,000 to 50,000. Commercially available PEGs can also be used, such as PEG1000, PEG1500, PEG1540, PEG2000, PEG4000, PEG6000, PEG10000, PEG20000, etc. These can be used individually or in mixtures of two or more types.

[0020] The copolymerization ratio of PEG to PPG in the above PEG / PPG copolymer is not particularly limited and can be adjusted as appropriate. For example, a PEG / PPG (mass ratio) in the range of 70 / 30 to 99 / 1 is preferred.

[0021] The above polyalkylene glycol may be used individually or as a mixture of two or more types. For example, PEG may be mixed with polypropylene glycol, PEG with polytetramethylene glycol, or PEG with PEG-PPG copolymer.

[0022] The polyalkylene glycol content in the seal layer (A) of the present invention is preferably 0.1 to 5.0% by mass, more preferably 0.1 to 3.0% by mass, even more preferably 0.3 to 3.0% by mass, and particularly preferably 0.5 to 2.5% by mass, based on the total mass of the seal layer (A). This content range is preferable because it provides a good balance between promoting the bleed of the antifogging agent and the film properties.

[0023] Furthermore, the ratio of the antifogging agent to the polyalkylene glycol content in the sealing layer (A) of the present invention is preferably 6:1 to 1:3, more preferably 5:1 to 1:2, and even more preferably 4:1 to 1:1. When this ratio is within this range, a good balance is achieved between the promotion of antifogging agent bleeding and the film properties.

[0024] (Freezing point of polyalkylene glycol) The freezing point of the polyalkylene glycol is preferably 40°C or higher. When the freezing point is 40°C or higher, the anti-fogging properties are more easily maintained even after the aging process. The freezing point in this invention is a value measured by the method specified in JIS K0065. The freezing point of the polyalkylene glycol is preferably 40°C or higher, more preferably 40-65°C, even more preferably 42-60°C, particularly preferably 45-58°C, and most preferably 50-56°C, from the viewpoint of suppressing the decrease in anti-fogging properties due to the aging process and achieving both film breakability.

[0025] The above PEG can also have its freezing point adjusted to a desired value by mixing polyethylene glycols with different number-average molecular weights. Furthermore, in the above PEG / PPG copolymer, the freezing point can also be adjusted to a desired value by appropriately adjusting the copolymerization ratio of PEG and PPG and / or the number-average molecular weight. In addition, the freezing point can also be adjusted to a desired value by using the above multiple polyalkylene glycols in combination.

[0026] <Polyester resin (a)> The sealing layer (A) used in the present invention contains a polyester resin (a). The polyester resin (a) comprises, as a polyhydric carboxylic acid component, a component selected from phthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, adipic acid, sebacic acid, naphthalenedicarboxylic acid, 4,4'-diphenylsulfondicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-phenylenedioxydiacetic acid, and structural isomers thereof, dicarboxylic acids or derivatives thereof such as malonic acid, succinic acid, and adipic acid, p-hydroxybenzoic acid, p-hydroxybenzoic acid esters, oxyacids or derivatives thereof such as glycolic acid, and as a polyhydric alcohol component, ethylene glycol, diethylene glycol, propylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyltrimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methylpentanediol, 1,6-hexanediol Polyhydric alcohols such as polyhydric alcohols like 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-icosanediol, 1,4-cyclohexanedimethanol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene ether glycol, neopentyl glycol, pentaethylene glycol, and trimethylolpropane, alicyclic glycols such as isosorbide, and aromatic dihydroxy compound derivatives such as bisphenol A and bisphenol S, can be selected and combined one or more of these components to carry out a transesterification or esterification reaction between the dibasic acid component and the glycol component, followed by a melt polycondensation reaction.

[0027] From the viewpoint of exhibiting sealing properties with polyester packaging containers, the sealing layer (A) used in the present invention preferably contains 90% by mass or more of the above-mentioned polyester resin (a) relative to the total amount of resin components forming the sealing layer (A).

[0028] Polyester resin (a) may be used alone or in combination of multiple types. In particular, it is preferable to use a combination of polyester resin (a1) having a glass transition temperature of 60 to 140°C and polyester resin (a2) having a glass transition temperature of 45°C or lower. By using polyester resin (a1) and polyester resin (a2) in combination, the anti-fogging function is more easily exhibited, and it is easier to achieve both anti-fogging properties and seal strength. The glass transition temperature (Tg) of polyester resin (a) is determined by a method conforming to the Japanese Industrial Standard (JIS K7121), i.e., differential scanning calorimetry (DSC).

[0029] (Polyester resin (a1)) The polyester resin (a1) is a polyester resin (a) having a glass transition temperature of 60 to 140°C. This polyester resin (a1) is obtained by polycondensation of a polycarboxylic acid and a polyhydric alcohol.

[0030] Examples of such polycarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, hexahydrophthalic acid, 1,4-cyclohexanedicarboxylic acid, maleic acid, maleic anhydride, citraconic acid, dimethylmaleic acid, cyclopentene-1,2-dicarboxylic acid, 1-cyclohexene-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, fumaric acid, mesaconic acid, itaconic acid, glutaconic acid, phthalic acid, phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, 1,2,5-hexanetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, trimellitic acid, trimellitic anhydride, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalentricarboxylic acid, pyromellitic acid, pyromellitic anhydride, etc. These may be used individually or in combination of two or more types. Furthermore, if necessary, monocarboxylic acids such as methaneic acid, ethaneic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, heptadecanoic acid, and octadecanoic acid may be used as raw material components.

[0031] Examples of the above polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyltrimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methylpentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-icosanediol, 1,4-cyclohexanedimethanol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene ether glycol, neopentyl glycol, pentaethylene glycol, isosorbide, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and trimethylolpropane. These can be used individually, or two or more can be used together. Among them,

[0032] The polycarboxylic acids and polyhydric alcohols mentioned above can be used in any combination. Specifically, examples include terephthalic acid / ethylene glycol / neopentyl glycol copolymer, terephthalic acid / ethylene glycol / 1,4-cyclohexanedimethanol / isosorbide copolymer, terephthalic acid / isophthalic acid / ethylene glycol copolymer, terephthalic acid / ethylene glycol / 1,4-cyclohexanedimethanol copolymer, and terephthalic acid / 1,4-cyclohexanedimethanol / 2,2,4,4-tetramethyl-1,3-cyclobutanediol copolymer.

[0033] The glass transition temperature of the above polyester resin (a1) is 60 to 140°C, but is preferably 60 to 130°C, and more preferably 60 to 120°C. By using a polyester resin (a1) with this glass transition temperature, suitable film processability and heat resistance can be ensured. Examples of such polyester resins (a1) include, but are not limited to, the resin commercially available under the trade name "ECOZEN" (SK Chemical Co., Ltd.).

[0034] (Polyester resin (a2)) The polyester resin (a2) is a polyester resin (a) having a glass transition temperature of 45°C or lower. This polyester resin (a2) is obtained by polycondensation of a polycarboxylic acid and a polyhydric alcohol.

[0035] Examples of the polycarboxylic acids mentioned above include aromatic polycarboxylic acids such as phthalic acid, phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, and trimellitic acid, as well as aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, decanoic acid, undecanediic acid, dodecanediic acid, tridecanediic acid, tetradecanediic acid, heptadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanediic acid, dimer acid, and cyclohexanedicarboxylic acid. These can be used individually, or two or more can be used together. Furthermore, if necessary, monocarboxylic acids such as methaneic acid, ethaneic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, heptadecanoic acid, and octadecanoic acid may be used as raw material components.

[0036] Examples of the polyhydric alcohols mentioned above include ethylene glycol, diethylene glycol, propylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyltrimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methylpentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-icosanediol, 1,4-cyclohexanedimethanol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene ether glycol, neopentyl glycol, pentaethylene glycol, and trimethylolpropane. These may be used individually or in combination of two or more types.

[0037] The polycarboxylic acids and polyhydric alcohols mentioned above can be used in any combination. Specifically, examples include terephthalic acid / ethylene glycol copolymer, terephthalic acid / 1,4-butanediol copolymer, terephthalic acid / adipic acid / 1,4-butanediol copolymer, terephthalic acid / polytetramethylene ether glycol / 1,4-butanediol copolymer, terephthalic acid / isophthalic acid / 1,4-butanediol / polytetramethylene ether glycol copolymer, terephthalic acid / isophthalic acid / 1,4-butanediol copolymer, terephthalic acid / isophthalic acid / 1,4-butanediol / polytetramethylene ether glycol / 1,4-butanediol copolymer, and so on.

[0038] The glass transition temperature of the above polyester resin (a2) is 45°C or lower, but is preferably -80 to 40°C, more preferably -80 to 0°C, and even more preferably -80°C to -20°C. By using a polyester resin (a2) with this glass transition temperature, the anti-fogging function is more easily achieved, and it becomes easier to achieve both anti-fogging properties and seal strength. Examples of such polyester resins (a2) include, but are not limited to, the resin sold commercially under the trade name "Byron" (Toyobo Co., Ltd.).

[0039] In the sealing layer (A) of the present invention, when a polyester resin (a1) having a glass transition temperature of 60 to 140°C and a polyester resin (a2) having a glass transition temperature of 45°C or less are used in combination as the polyester resin (a), it is preferable that the total content of the polyester resin (a1) and polyester resin (a2) in the sealing layer (A) be 70% by mass or more in order to obtain suitable heat sealability and heat resistance. Furthermore, it is more preferable that the content be 75% by mass or more, and more preferably 80% by mass or more, in order to obtain a suitable film appearance. There is no particular upper limit to the content, but it is preferable that it be 99% by mass or less, and more preferably 97% by mass or less.

[0040] The content of the polyester resin (a1) in the sealing layer (A) of the present invention is preferably 20 to 90% by mass, more preferably 30 to 80% by mass, and even more preferably 50 to 70% by mass. Furthermore, the content of the polyester resin (a2) in the sealing layer (A) of the present invention is preferably 10 to 80% by mass, more preferably 20 to 70% by mass, and even more preferably 30 to 50% by mass. When the content is within this range, it is preferable to achieve both anti-fogging properties and heat-sealing properties.

[0041] Furthermore, the content ratio of the polyester resin (a1) to the polyester resin (a2) is preferably 20:80 to 90:10, more preferably 30:70 to 80:20, and even more preferably 50:50 to 70:30. When the content ratio is within this range, the antifogging function is easily exhibited, achieving both antifogging and film breakage properties, and also resulting in good transparency.

[0042] The polyester resin (a) in the sealing layer (A) used in the present invention may be a biodegradable polyester. Examples of biodegradable polyesters include polylactic acid resins, poly(butylene succinate) (PBS), poly(butylene succinate / adipate) copolymers (PBSA), poly(3-hydroxybutyric acid), copolymers of 3-hydroxybutyric acid and 3-hydroxyvaleric acid, copolymers of 3-hydroxybutyric acid and 4-hydroxybutyric acid, and other polyhydroxyalkanoates; aliphatic polyester compounds such as polyglycolic acid, polycaprolactone, ring-opening polymers such as β-propiolactone and γ-valerolactone; polyesters composed of aliphatic dibasic acids and aliphatic diols, such as adipic acid, 1,4-butanediol and terephthalic acid copolyester (polybutylene adipate terephthalate), and polyesters composed of succinic acid and ethylene glycol (polyethylene succinate); copolymers of aromatic polyesters and aliphatic polyesters; copolymers of aliphatic polyesters and polyamides. Furthermore, it may also contain other biodegradable resins such as polyvinyl alcohol, pullulan, chitosan, curdlan, starch-based green plastic, esterified starch, cellulose, and cellulose acetate.

[0043] The resin constituting the seal layer (A) in the present invention may be used in combination with other resins, as long as it does not impair sealing and anti-fogging properties. From the viewpoint of achieving sealing properties with polyester packaging containers, the content of the other resins in the seal layer (A) is preferably 10% by mass or less, preferably 5% by mass or less, and more preferably none, based on the total amount of resin components forming the seal layer (A).

[0044] Examples of the above-mentioned other resins include polyolefin resins such as ethylene resins, propylene resins, and cyclic olefin resins; thermoplastic elastomers such as polyethylene elastomers, polypropylene elastomers, and butene elastomers; ethylene copolymers such as ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), and ethylene-methacrylic acid copolymer (EMAA); and further, ionomers of ethylene-acrylic acid copolymer, ionomers of ethylene-methacrylic acid copolymer, and the above-mentioned other biodegradable resins. Examples of ethylene-based resins include polyethylene resins such as ultra-low density polyethylene (VLDPE), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), linear medium-density polyethylene (LMDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE). Examples of propylene-based resins include propylene homopolymers, propylene-α-olefin random copolymers such as propylene-ethylenebutene-1 copolymers, and propylene block copolymers such as propylene-α-olefin block copolymers. Examples of cyclic olefin-based resins include norbornene polymers, vinyl alicyclic hydrocarbon polymers, and cyclic conjugated diene polymers. Among these, norbornene polymers are preferred. Examples of norbornene polymers include ring-opening polymers of norbornene monomers (hereinafter sometimes referred to as "COP") and norbornene copolymers obtained by copolymerizing norbornene monomers with olefins such as ethylene (hereinafter sometimes referred to as "COC").

[0045] The sealing layer (A) used in the present invention may contain components such as antistatic agents, heat stabilizers, nucleating agents, antioxidants, lubricants, antiblocking agents, mold release agents, ultraviolet absorbers, colorants, and biodegradability-granting agents, to the extent that they do not impair the objectives of the present invention. When using these additives, they should preferably be used in amounts of 10 parts by mass or less, and more preferably 8 parts by mass or less, per 100 parts by mass of the resin component used in the sealing layer. In particular, to provide processability during multilayer film molding and packaging suitability for filling machines, the coefficient of friction of the multilayer film surface is preferably 2.0 or less, and more preferably 1.5 or less. Therefore, it is preferable to appropriately add lubricants, antiblocking agents, and antistatic agents to the seal layer (A), which is the surface layer of the multilayer film of the present invention. The additives such as lubricants and antiblocking agents are not particularly limited, and commercially available ones can be used.

[0046] <Resin layer (B)> The resin layer (B) of the present invention is a layer adjacent to the sealing layer (A) and comprises an acid-modified polyolefin and a polyester resin (b).

[0047] <Acid-modified polyolefins> The resin layer (B) of the present invention contains an acid-modified polyolefin. The olefin component constituting the main chain of the acid-modified polyolefin is not particularly limited, but alkenes having 2 to 6 carbon atoms, such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, and 1-hexene, are preferred, and mixtures thereof may also be used. Among these, alkenes having 2 to 4 carbon atoms, such as ethylene, propylene, isobutylene, and 1-butene, are more preferred, ethylene and propylene are even more preferred, and ethylene is the most preferred.

[0048] Furthermore, the above-mentioned acid-modified polyolefin contains a (meth)acrylic acid ester component. Examples of (meth)acrylic acid ester components include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, and stearyl (meth)acrylate. From the viewpoint of ease of availability and adhesiveness, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and hexyl acrylate are more preferred, and methyl acrylate and ethyl acrylate are even more preferred. In addition, the (meth)acrylic acid ester component only needs to be copolymerized with the olefin component, and its form is not limited. Examples of copolymerization states include random copolymerization, block copolymerization, and graft copolymerization (graft modification). (Note that "(meth)acrylic acid" means "acrylic acid or methacrylic acid.") Specifically, examples of ethylene-(meth)acrylic acid ester copolymers include Elvaloy (trade name: manufactured by Dow Chemical Co., Ltd.) and Acrylift (trade name: manufactured by Sumitomo Chemical Co., Ltd.). These may be used individually or as a mixture of two or more.

[0049] Furthermore, the above-mentioned acid-modified polyolefin may be acid-modified with an unsaturated carboxylic acid component. Examples of unsaturated carboxylic acid components include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, crotonic acid, as well as half-esters and half-amides of unsaturated dicarboxylic acids. Among these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferred, with acrylic acid and maleic anhydride being particularly preferred. The unsaturated carboxylic acid component only needs to be copolymerized with the olefin component, and its form is not limited. Examples of copolymerization states include random copolymerization, block copolymerization, and graft copolymerization (graft modification). Specifically, for example, as an ethylene-acrylic acid copolymer, Nucrel (trade name: manufactured by Dow Chemical Corporation) is an example. As an ethylene-(meth)acrylic acid ester-maleic anhydride copolymer, Bondine (trade name: manufactured by Arkema) is an example. These may be used individually or in combination of two or more.

[0050] As for the acid modification rate of the above-mentioned acid-modified polyolefin, it is preferable to use one with a rate of 0.5 to 40% from the viewpoint of good adhesion, more preferably 0.5 to 35%, and particularly preferably 0.5 to 30%.

[0051] In the present invention, the resin layer (B) preferably contains 40 to 95% by mass of the above-mentioned acid-modified polyolefin, more preferably 51 to 95% by mass, and even more preferably 55 to 90% by mass. By setting the content of the acid-modified polyolefin within this range, sufficient interlayer strength can be obtained between the seal layer (A) and the resin layer (B).

[0052] <Polyester resin (b)> The resin layer (B) of the present invention uses a polyester resin (b) in combination with the acid-modified polyolefin. By using the acid-modified polyolefin and the polyester resin (b) in combination, the interlayer strength between the seal layer (A) containing the anti-fogging agent and the resin layer (B) is greatly improved without degrading transparency, and the film breakability is improved.

[0053] The polyester resin (b) can be the same as the polyester resin (a) described above, but it is particularly preferable to use a polyester resin (b) having a glass transition temperature of 45°C or lower, and can be the same as the polyester resin (a2) described above. By using a polyester resin (b) having a glass transition temperature of 45°C or lower, interlayer adhesion is improved even with the presence of an antifogging agent, and as a result the amount of antifogging agent in the seal layer (A) can be increased, leading to improved antifogging performance. Biodegradable polyester may also be used. The polyester resin (b) is preferably a polyester resin (b) obtained by polycondensation of a low molecular weight polyhydric alcohol with a molecular weight of 2000 or less and a polyhydric carboxylic acid. The glass transition temperature of the polyester resin (b) is preferably 45°C or lower, more preferably -80 to 40°C, even more preferably -80 to 0°C, and particularly preferably -80°C to -20°C.

[0054] The content of the polyester resin (b) in the resin layer (B) of the present invention is preferably 5 to 60% by mass, more preferably 5 to 49% by mass, and even more preferably 10 to 45% by mass.

[0055] The mass ratio of the acid-modified polyolefin to the polyester resin (b) in the resin layer (B) of the present invention is preferably 30:70 to 95:5, more preferably 40:60 to 95:5, and even more preferably 45:55 to 95:5. When the mass ratio is within this range, the interlayer strength is improved, which makes it easier to improve film breakability.

[0056] Polyolefin resins can be added to the above-mentioned resin layer (B) to the extent that they do not impair the objectives of the present invention.

[0057] Examples of polyolefin resins mentioned above include ethylene resins, propylene resins, and cyclic olefin resins, but are not limited to these. The resin that will be the main component of each layer should be appropriately selected according to the properties required for each layer of the multilayer film.

[0058] Examples of the ethylene-based resins mentioned above include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE), which may be used individually or in combination. Among these, high-density polyethylene is preferred.

[0059] The low-density polyethylene (LDPE) mentioned above refers to 0.935 g / cm³. 3 This refers to a homopolymer of ethylene having a density of less than [amount missing].

[0060] The above-mentioned linear low-density polyethylene is produced by low-pressure radical polymerization using a multi-site catalyst, such as the Ziegler-Natta catalyst, or a single-site catalyst, with ethylene monomers as the main component, copolymerized with α-olefins such as butene-1, hexene-1, octene-1, and 4-methylpentene as comonomers, and has a density of 0.925 g / cm³. 3 This refers to materials with a comonomer content less than 100%. Therefore, it is distinguished from low-density polyethylene (LDPE), which is a homopolymer of ethylene. The comonomer content in linear low-density polyethylene is preferably in the range of 0.5 to 20 mol%, and more preferably in the range of 1 to 18 mol%. When butene-1 is used as the comonomer, transparency, impact resistance, and tear resistance are improved, so it is preferable, and in this case, the content of the butene monomer is most preferably in the range of 1 to 5 mol%.

[0061] Examples of the single-site catalysts mentioned above include various metallocene catalyst systems such as combinations of metallocene compounds of Group IV or V transition metals in the periodic table and organoaluminum compounds and / or ionic compounds. Furthermore, since single-site catalysts have a uniform active site, they are preferable to multi-site catalysts, which have a sharper molecular weight distribution in the resulting resin compared to multi-site catalysts with non-uniform active sites. This results in less precipitation of low molecular weight components when the resin is formed into a film, and allows for the acquisition of a resin with excellent physical properties such as stable seal strength and resistance to blocking.

[0062] The above medium-density polyethylene (MDPE) refers to 0.925 g / cm³. 3 More than 0.942g / cm 3 This refers to a copolymer of ethylene and α-olefin having a density of less than 1%. As the amount of α-olefin acting as comonomer increases, the density decreases, so it is preferable to have fewer comonomers. Specifically, a comonomer ratio of 0.5 to 1% is preferred, but it is not limited to this range.

[0063] The above high-density polyethylene (HDPE) refers to 0.942 g / cm³ 3 This refers to polyethylene having the density specified above. It may be a homopolymer of ethylene or a copolymer of ethylene and α-olefin, but since the density decreases as the amount of α-olefin acting as comonomer increases, it is preferable to have fewer comonomers, and specifically, it is preferable that the comonomer ratio is 0.5% or less.

[0064] Since the comonomer ratio is not disclosed in some commercially available products, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene can be distinguished by density, and low-density polyethylene and medium-density polyethylene can be distinguished by whether or not they are homopolymers of ethylene. In this invention, even if a product is commercially available as linear low-density polyethylene, if its density is 0.925 g / cm³, 3 The above materials should be treated as medium-density polyethylene. For example, a density of 0.926 g / cm³ is also acceptable. 3If there is polyethylene, if it is a homopolymer of ethylene, it can be treated as low-density polyethylene, and if it is a copolymer of ethylene and α-olefin, it can be treated as medium-density polyethylene.

[0065] Also, as the ethylene-based resin, polyethylene derived from biomass may be used. For example, low-density polyethylene derived from biomass manufactured by Braskem (product name: SBC818, density: 0.918 g / cm 3 , MFR: 8.1 g / 10 min), low-density polyethylene derived from biomass manufactured by Braskem (product name: SPB681, density: 0.922 g / cm 3 , MFR: 3.8 g / 10 min), linear low-density polyethylene derived from biomass manufactured by Braskem (product name: SLL118, density: 0.916 g / cm 3 , MFR: 1.0 g / 10 min), etc. can be mentioned.

[0066] Also, ethylene-based copolymers such as ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), etc. can be mixed and used with the ethylene-based resin. Furthermore, ionomers of ethylene-acrylic acid copolymer, ionomers of ethylene-methacrylic acid copolymer, etc. may be mixed and used.

[0067] Examples of the above propylene-based resins include propylene homopolymer, propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-ethylene-butene-1 copolymer, metallocene catalyst-based polypropylene, etc. These may be used alone or in combination. In particular, when using a propylene-based copolymer as the propylene-based resin, it is preferable because seal strength is easily obtained.

[0068] Examples of the above-mentioned cyclic olefin resins include norbornene polymers, vinyl alicyclic hydrocarbon polymers, and cyclic conjugated diene polymers. Among these, norbornene polymers are preferred. Examples of norbornene polymers include ring-opening polymers of norbornene monomers (hereinafter sometimes referred to as "COP") and norbornene copolymers obtained by copolymerizing norbornene monomers with olefins such as ethylene (hereinafter sometimes referred to as "COC"). Hydrogenated COP and COC are particularly preferred. The weight-average molecular weight of the cyclic olefin resin is preferably 5,000 to 500,000, and more preferably 7,000 to 300,000.

[0069] The norbornene polymers and norbornene monomers used as raw materials are alicyclic monomers having a norbornene ring. Examples of such norbornene monomers include norbornene, tetracyclododecene, ethylidenenorbornene, vinylnorbornene, ethylidetetracyclododecene, dicyclopentadiene, dimethanotetrahydrofluorene, phenylnorbornene, methoxycarbonylnorbornene, and methoxycarbonyltetracyclododecene. These norbornene monomers may be used individually or in combination of two or more.

[0070] The norbornene copolymer (COC) described above is obtained by copolymerizing the norbornene monomer with a copolymerizable olefin. Examples of such olefins include olefins having 2 to 20 carbon atoms, such as ethylene, propylene, and 1-butene; cycloolefins, such as cyclobutene, cyclopentene, and cyclohexene; and non-conjugated dienes, such as 1,4-hexadiene. These olefins can be used individually or in combination of two or more types.

[0071] Furthermore, the content ratio of norbornene monomers in the norbornene copolymer (COC) is preferably 40 to 90 mol%, and more preferably 50 to 80 mol%. When the content ratio is within this range, the rigidity, tear resistance, and processing stability of the film are improved.

[0072] Examples of commercially available cyclic olefin resins that can be used include, as a ring-opening polymer (COP) of norbornene monomers, "ZEONOR" manufactured by Nippon Zeon Co., Ltd., and as a norbornene copolymer (COC), "APPEL" manufactured by Mitsui Chemicals, Inc. and "TOPAS" manufactured by TICONA.

[0073] In addition to the resin layer (B) described above, components such as antistatic agents, heat stabilizers, nucleating agents, antioxidants, lubricants, antiblocking agents, mold release agents, ultraviolet absorbers, colorants, and biodegradability-granting agents can be added to the resin layer (B) to the extent that they do not impair the objectives of the present invention.

[0074] (Other layers) The multilayer film of the present invention may include layers other than the seal layer (A) and the resin layer (B). The other layers are not particularly limited, but a polyolefin resin layer is preferred, such as a polyester resin layer or a polyolefin resin layer. It is also preferable that the other layers include two or more polyolefin resin layers. In this case, the layer that constitutes the other surface of the multilayer film of the present invention other than the seal layer (A) is referred to as the "laminate layer," and the layer located between the laminate layer and the resin layer (B) is referred to as the "intermediate layer."

[0075] (Polyolefin resin layer) The multilayer film of the present invention preferably includes two or more polyolefin-based resin layers in addition to the sealing layer (A) and resin layer (B) described above.

[0076] Examples of polyolefin resins mentioned above include ethylene resins, propylene resins, and cyclic olefin resins, but are not limited to these. The resin that will be the main component of each layer should be appropriately selected according to the properties required for each layer of the multilayer film.

[0077] Examples of the ethylene-based resins mentioned above include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE), which may be used individually or in combination. Among these, linear low-density polyethylene is preferred.

[0078] The low-density polyethylene (LDPE) mentioned above refers to 0.935 g / cm³. 3 This refers to a homopolymer of ethylene having a density of less than [amount missing].

[0079] The above-mentioned linear low-density polyethylene is produced by low-pressure radical polymerization using a multi-site catalyst, such as the Ziegler-Natta catalyst, or a single-site catalyst, with ethylene monomers as the main component, copolymerized with α-olefins such as butene-1, hexene-1, octene-1, and 4-methylpentene as comonomers, and has a density of 0.925 g / cm³. 3 This refers to materials with a comonomer content less than 100%. Therefore, it is distinguished from low-density polyethylene (LDPE), which is a homopolymer of ethylene. The comonomer content in linear low-density polyethylene is preferably in the range of 0.5 to 20 mol%, and more preferably in the range of 1 to 18 mol%. When butene-1 is used as the comonomer, transparency, impact resistance, and tear resistance are improved, so it is preferable, and in this case, the content of the butene monomer is most preferably in the range of 1 to 5 mol%.

[0080] Examples of the single-site catalysts mentioned above include various metallocene catalyst systems such as combinations of metallocene compounds of Group IV or V transition metals in the periodic table and organoaluminum compounds and / or ionic compounds. Furthermore, since single-site catalysts have a uniform active site, they are preferable to multi-site catalysts, which have a sharper molecular weight distribution in the resulting resin compared to multi-site catalysts with non-uniform active sites. This results in less precipitation of low molecular weight components when the resin is formed into a film, and allows for the acquisition of a resin with excellent physical properties such as stable seal strength and resistance to blocking.

[0081] The above medium-density polyethylene (MDPE) refers to 0.925 g / cm³. 3 More than 0.942g / cm 3 This refers to a copolymer of ethylene and α-olefin having a density of less than 1%. As the amount of α-olefin acting as comonomer increases, the density decreases, so it is preferable to have fewer comonomers. Specifically, a comonomer ratio of 0.5 to 1% is preferred, but it is not limited to this range.

[0082] The above high-density polyethylene (HDPE) refers to 0.942 g / cm³ 3 This refers to polyethylene having the density specified above. It may be a homopolymer of ethylene or a copolymer of ethylene and α-olefin, but since the density decreases as the amount of α-olefin acting as comonomer increases, it is preferable to have fewer comonomers, and specifically, it is preferable that the comonomer ratio is 0.5% or less.

[0083] Since the comonomer ratio is not disclosed in some commercially available products, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene can be distinguished by density, and low-density polyethylene and medium-density polyethylene can be distinguished by whether or not they are homopolymers of ethylene. In this invention, even if a product is commercially available as linear low-density polyethylene, if its density is 0.925 g / cm³, 3 The above materials should be treated as medium-density polyethylene. For example, a density of 0.926 g / cm³ is also acceptable. 3 If polyethylene is present, it should be treated as low-density polyethylene if it is a homopolymer of ethylene, and as medium-density polyethylene if it is a copolymer of ethylene and α-olefin.

[0084] Furthermore, biomass-derived polyethylene may be used as the ethylene-based resin, for example, low-density biomass-derived polyethylene manufactured by Braskem (product name: SBC818, density: 0.918 g / cm³). 3 (MFR: 8.1g / 10 min), low-density polyethylene derived from biomass manufactured by Braskem (product name: SPB681, density: 0.922g / cm³) 3(MFR: 3.8g / 10 min), linear low-density polyethylene (product name: SLL118, density: 0.916g / cm³) derived from biomass, manufactured by Braskem. 3 Examples include MFR: 1.0g / 10 mins.

[0085] Furthermore, ethylene-based polymers such as ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), and ethylene-methacrylic acid copolymer (EMAA) may be mixed with the ethylene-based resin and used.

[0086] Examples of the propylene-based resins mentioned above include propylene homopolymers, propylene-ethylene copolymers, propylene-butene-1 copolymers, propylene-ethylene-butene-1 copolymers, and metallocene catalyst-based polypropylenes. These may be used individually or in combination. In particular, using a propylene-based copolymer as the polypropylene-based resin is preferable because it is easier to obtain seal strength.

[0087] Examples of the above-mentioned cyclic olefin resins include norbornene polymers, vinyl alicyclic hydrocarbon polymers, and cyclic conjugated diene polymers. Among these, norbornene polymers are preferred. Examples of norbornene polymers include ring-opening polymers of norbornene monomers (hereinafter sometimes referred to as "COP") and norbornene copolymers obtained by copolymerizing norbornene monomers with olefins such as ethylene (hereinafter sometimes referred to as "COC"). Hydrogenated COP and COC are particularly preferred. The weight-average molecular weight of the cyclic olefin resin is preferably 5,000 to 500,000, and more preferably 7,000 to 300,000.

[0088] The norbornene polymers and norbornene monomers used as raw materials are alicyclic monomers having a norbornene ring. Examples of such norbornene monomers include norbornene, tetracyclododecene, ethylidenenorbornene, vinylnorbornene, ethylidetetracyclododecene, dicyclopentadiene, dimethanotetrahydrofluorene, phenylnorbornene, methoxycarbonylnorbornene, and methoxycarbonyltetracyclododecene. These norbornene monomers may be used individually or in combination of two or more.

[0089] The norbornene copolymer (COC) described above is obtained by copolymerizing the norbornene monomer with a copolymerizable olefin. Examples of such olefins include olefins having 2 to 20 carbon atoms, such as ethylene, propylene, and 1-butene; cycloolefins, such as cyclobutene, cyclopentene, and cyclohexene; and non-conjugated dienes, such as 1,4-hexadiene. These olefins can be used individually or in combination of two or more types.

[0090] Furthermore, the content ratio of norbornene monomers in the norbornene copolymer (COC) is preferably 40 to 90 mol%, and more preferably 50 to 80 mol%. When the content ratio is within this range, the rigidity, tear resistance, and processing stability of the film are improved.

[0091] Examples of commercially available cyclic olefin resins that can be used include, as a ring-opening polymer (COP) of norbornene monomers, "ZEONOR" manufactured by Nippon Zeon Co., Ltd., and as a norbornene copolymer (COC), "APPEL" manufactured by Mitsui Chemicals, Inc. and "TOPAS" manufactured by TICONA.

[0092] Furthermore, as the other resin used as the resin component of the polyolefin resin layer described above, recovered film edges and other materials generated during the production of the multilayer film of the present invention and film edges and other materials generated during the production of the ethylene-based film may also be mixed. Here, an ethylene-based film means a film in which the proportion of the above-mentioned ethylene-based resin in the total resin constituting the film is 70% by mass or more. When the recovered product is added to a polyolefin resin layer, it is preferable to use it in an amount of 1 to 45% by mass of the resin components contained in the polyolefin resin layer, more preferably 5 to 40% by mass, even more preferably 10 to 35% by mass, and still more preferably 10 to 30% by mass.

[0093] (Laminate layer) The multilayer film of the present invention preferably includes a laminate layer. This laminate layer is a layer mainly composed of a polyolefin resin and, as described above, constitutes the other surface layer of the multilayer film of the present invention, as opposed to the sealing layer (A). It is also the layer to be bonded to other substrates when laminating it with other substrates to form a laminate.

[0094] Examples of polyolefin resins that form the main component of the laminate layer include the ethylene resins and propylene resins mentioned above. From the viewpoint of preventing delamination between the layer and the base film, the density should be 0.880 to 0.960 g / cm³. 3 The following ethylene-based resins or propylene-α-olefin random copolymers polymerized using a single-site catalyst are preferred, with ethylene-based resins being particularly preferred, and linear low-density polyethylene being more preferred.

[0095] As mentioned above, the density of the above ethylene-based resin is 0.880 to 0.960 g / cm³. 3 Preferably, it is 0.890 to 0.940 g / cm³. 3 It is more preferable that the value be 0.890-0.935 g / cm³. 3It is even more preferable that the density is within this range. If the density is within this range, it will have appropriate rigidity, excellent mechanical strength such as pinhole resistance, and improved film formation and extrusion suitability. In addition, the melting point is generally preferably in the range of 60 to 140°C, more preferably 70 to 135°C, and even more preferably 90 to 130°C. If the melting point is within this range, processing stability (dead hold) and co-extrusion processability will be improved. Furthermore, the MFR (190°C, 21.18N) of the ethylene resin is preferably 0.5 to 50 g / 10 min, more preferably 1 to 30 g / 10 min, even more preferably 2 to 20 g / 10 min, and particularly preferably 5 to 15 g / 10 min. An MFR within this range is preferable because it allows for good film formation. By using such ethylene-based resins, transparency can be maintained when laminated. Furthermore, its flexibility results in good pinhole resistance.

[0096] The propylene-based resin used in the laminate layer preferably has an MFR (at 230°C) of 0.5 to 30.0 g / 10 min and a melting point of 110 to 165°C, and more preferably has an MFR (at 230°C) of 2.0 to 15.0 g / 10 min and a melting point of 115 to 162°C. If the MFR and melting point are within this range, the film-forming properties of the film will be improved.

[0097] There are no particular restrictions on the density of the above-mentioned propylene resin, and it can be appropriately selected according to the purpose, but 0.89 g / cm³ is acceptable. 3 ~0.93g / cm 3 Preferably, 0.90 g / cm³ 3 ~0.92g / cm 3 This is preferable.

[0098] There are no particular restrictions on the melting point of the propylene resin mentioned above, and it can be appropriately selected depending on the purpose, but 110°C to 170°C is preferred, 121°C to 166°C is more preferred, and 121°C to 140°C is even more preferred.

[0099] As mentioned above, the laminate layer is mainly composed of polyolefin resin, but when laminating with other substrates using adhesives, or when printing, other resins other than polyolefin resin may be used in combination to improve adhesion with adhesives and printing inks. Other resins other than polyolefin resin that can be used in combination include ethylene copolymers such as ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), and ethylene-methacrylic acid copolymer (EMAA); furthermore, ionomers of ethylene-acrylic acid copolymer, ionomers of ethylene-methacrylic acid copolymer, and copolymers of monomers having a cyclic olefin structure such as norbornene monomers with ethylene, etc., and these may be used individually or in combination of two or more types.

[0100] The laminate layer described above may contain components such as anti-fogging agents, antistatic agents, heat stabilizers, nucleating agents, antioxidants, lubricants, antiblocking agents, mold release agents, ultraviolet absorbers, colorants, and biodegradability-enhancing agents, to the extent that they do not impair the objectives of the present invention. When using these additives, they are preferably used in amounts of 10 parts by mass or less, and more preferably 8 parts by mass or less, per 100 parts by mass of the resin component used in the base layer. In particular, to provide good processability during film formation and packaging suitability for filling machines, the coefficient of friction of the multilayer film surface is preferably 2.0 or less, and more preferably 1.5 or less. Therefore, it is preferable to appropriately add lubricants, antiblocking agents, and antistatic agents to the laminate layer, which corresponds to the surface layer of the multilayer film. The additives such as lubricants and antiblocking agents are not particularly limited, and commercially available ones can be used. In addition, the anti-fogging agents described in detail in the sealing layer (A) can be used as anti-fogging agents.

[0101] (Middle class) The multilayer film of the present invention may include an intermediate layer. This intermediate layer is a layer mainly composed of a polyolefin resin and, as described above, is located between the laminate layer and the resin layer (B). The polyolefin resin that is the main component of the intermediate layer can be the same polyolefin resin as the polyolefin resin that is the main component of the laminate layer, and the same applies to preferred polyolefin resins. The polyolefin resin used in the intermediate layer and the polyolefin resin used in the laminate layer may be the same polyolefin resin or different polyolefin resins, but it is preferable to use a combination of polyolefin resins of the same type to reduce the likelihood of delamination between layers. When combining polyolefin resins of the same type, their densities may be the same or different.

[0102] The proportion of the polyolefin resin used in the intermediate layer is preferably 50% by mass or more, preferably 70% by mass or more, and particularly preferably 90% by mass or more. Other resins that can be used in combination are the same as those exemplified as resins that can be used in combination in the laminate layer.

[0103] The intermediate layer may not be present in the multilayer film of the present invention, may be a single layer, or may consist of two or more layers.

[0104] In the intermediate layer, components such as antistatic agents, heat stabilizers, nucleating agents, antioxidants, lubricants, antiblocking agents, mold release agents, ultraviolet absorbers, colorants, and biodegradability-enhancing agents can be added to the extent that they do not impair the objectives of the present invention. Furthermore, the intermediate layer may also contain an antifogging agent. When an antifogging agent is included in the intermediate layer, the seal strength may decrease due to the migration of the antifogging agent between layers, but in the multilayer film of the present invention, such problems are less likely to occur.

[0105] <Multilayer film> The multilayer film of the present invention is a multilayer film comprising a sealing layer (A) and a resin layer (B) adjacent to the sealing layer (A). For example, the layer configuration is as follows: (1) (Laminate layer) / (Intermediate layer) / (Resin layer (B)) / (Seal layer (A)) (2) (Laminate layer) / (Resin layer (B)) / (Seal layer (A)) (3) (Laminate layer) / (Intermediate layer) / (Intermediate layer) / (Resin layer (B)) / (Seal layer (A)) These are just a few examples of specific embodiments of the present invention, and the invention is not limited to these. In particular, the configuration of (1), in which a (laminate layer) / (intermediate layer) / (resin layer (B)) / (seal layer (A)) are laminated together, is preferred.

[0106] The multilayer film of the present invention achieves suitable seal strength when heat-sealed, and maintains suitable easy opening properties with good film breakage between the seal layer (A) and resin layer (B) used in the present invention when opened. Furthermore, even when stored in an environment of about 40°C for transportation or aging treatment, the migration of the anti-fogging agent to the substrate surface in contact with it is suppressed, and stable anti-fogging performance can be exhibited.

[0107] The total thickness of the multilayer film of the present invention is preferably 20 μm or more, as this facilitates film formation. Furthermore, the total thickness is preferably 100 μm or less, and particularly preferably 50 μm or less, as this facilitates lamination when the multilayer film of the present invention is used in combination with other substrates. In addition, from the viewpoint of reducing environmental impact, there is a demand for thinner packaging materials. The multilayer film of the present invention can achieve the effects of the present invention even when the total thickness is less than 30 μm, so a total thickness of 20 μm or more and less than 30 μm is also preferable.

[0108] Furthermore, regarding the ratio of each layer in the multilayer film, from the viewpoint of sealing properties, ease of opening, and lamination properties, it is preferable that the thickness ratio of the laminate layer is in the range of 20 to 85%, the thickness ratio of the resin layer (B) is in the range of 10 to 40%, and the thickness ratio of the sealing layer (A) is in the range of 5 to 20%.

[0109] The total amount of antifogging agent contained in the antifogging multilayer film of the present invention is preferably 0.1% by mass or more relative to the total mass of the film. When the total amount of antifogging agent is within this range, suitable antifogging properties and durability of antifogging can be obtained. Furthermore, the upper limit of the total amount of antifogging agent is preferably 0.7% by mass or less, and particularly preferably 0.5% by mass or less, relative to the total mass of the film. When the total amount of antifogging agent is within this range, the film breakability is good, and deterioration of seal strength over time is easily suppressed.

[0110] In the multilayer film of the present invention, it is preferable that the laminate layer side surface is treated to have a wet tensile strength in the range of 35 to 45 mN / m. Examples of such treatment methods include surface oxidation treatments such as corona discharge treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment, or surface roughening treatments such as sandblasting, but corona discharge treatment is preferred. By performing such surface treatment, when post-processing such as printing or applying adhesive to the laminate layer side surface of the multilayer film and laminating it with a substrate is performed, the coatability of inks and adhesives is improved, and adhesion with inks, aluminum, anchor coating agents, etc. is excellent, making it easy to avoid problems such as detachment of inks and vapor-deposited aluminum, and delamination.

[0111] Furthermore, in the multilayer film of the present invention, it is also preferable that the surface on the sealing layer (A) side is treated to have a wet tensile strength in the range of 40 to 55 mN / m. By treating the surface on the sealing layer (A) side, it becomes possible to fix the anti-fogging agent to the surface for a relatively long period of time, resulting in a film with excellent anti-fogging properties and anti-fogging durability. The treatment method and degree of treatment for the laminate layer side surface and the seal layer (A) side surface may be the same or different, but from the viewpoint of productivity, it is preferable to treat them using the same method.

[0112] (Manufacturing method) The method for manufacturing the multilayer film of the present invention is not particularly limited, but for example, a co-extrusion method is used in which each resin or resin mixture used for each layer is heated and melted in separate extruders, and then laminated in the order that results in the layer configuration of the present invention in the molten state using methods such as the co-extrusion multilayer die method or the feed block method, and then formed into a film using methods such as inflation or the T-die chill roll method. This co-extrusion method is preferred because it allows for relatively free adjustment of the thickness ratio of each layer, and a multilayer film with excellent hygiene and cost performance can be obtained. Among these, the T-die chill roll method is preferred because it suppresses deterioration of the film appearance when co-extruding resins with different melting points and Tg, and makes it easy to form a uniform layer structure, making it easy to obtain a multilayer film with suitable transparency and gloss. The inflation method is also preferred because the equipment is simple and it is suitable for small-batch, high-mix production.

[0113] Since the multilayer film of the present invention is obtained as a substantially unstretched multilayer film by the above manufacturing method, secondary molding such as deep drawing by vacuum forming and embossing is also possible.

[0114] Furthermore, embossing may be applied by bringing a roll with an uneven surface into contact with the laminate layer or seal layer (A) immediately after extrusion.

[0115] Furthermore, in order to stabilize the physical properties of the multilayer film, it may be stored in an environment of about 40°C and subjected to aging treatment. The multilayer film of the present invention maintains good anti-fogging properties, with the deterioration of anti-fogging properties suppressed even after aging treatment.

[0116] (Laminated structure) The multilayer film of the present invention can be laminated by bonding it with a substrate or by other means to form a laminate. The structure of the laminate of the present invention is as follows: (1) Substrate / Adhesive layer / Multilayer film of the present invention (2) Substrate / Adhesive layer / Printed layer / Multilayer film of the present invention (3) Substrate / Adhesive layer / Second substrate / Printed layer / Adhesive layer / Multilayer film of the present invention (4) Substrate / Adhesive layer / First printing layer / Second printing layer / Multilayer film of the present invention (5) Substrate / Adhesive layer / Barrier layer / Adhesive layer / Multilayer film of the present invention (6) Substrate / Adhesive layer / Barrier layer / Printed layer / Adhesive layer / Multilayer film of the present invention (7) Substrate / Printing layer / Adhesive layer / Multilayer film of the present invention (8) Substrate / First printing layer / Second printing layer / Adhesive layer / Multilayer film of the present invention (9) Substrate / Printing layer / Adhesive layer / Barrier layer / Adhesive layer / Multilayer film of the present invention (10) Substrate / Adhesive layer / Barrier layer / Adhesive layer / Second substrate / Adhesive layer / Multilayer film of the present invention (11) Substrate / Printing layer / Adhesive layer / Barrier layer / Adhesive layer / Second substrate / Adhesive layer / Multilayer film of the present invention Examples include, but are not limited to, additional base materials may be included. The second and additional substrates may be unstretched resin films, stretched resin films, metal-deposited films such as unstretched metal-deposited films or stretched metal-deposited films, transparent metal-deposited films, or papers such as coated paper or fine paper, and are not particularly limited. Furthermore, the multiple adhesive layers may have the same composition or different compositions. Furthermore, to improve the adhesive strength of the adhesive layer, an anchor coat layer may be sandwiched between the layers.

[0117] The method for laminating the multilayer film and the base film of the present invention is not particularly limited, and composite lamination technologies such as dry lamination, wet lamination, non-solvent lamination, extrusion lamination, sand lamination, and heat lamination may be used. However, even when a technology requiring an aging treatment at around 40°C is used during lamination, good anti-fogging properties are maintained when using the multilayer film of the present invention.

[0118] Examples of the stretched resin films mentioned above include biaxially oriented polyester (PET), easily tearable biaxially oriented polyester (PET), biaxially oriented polypropylene (OPP), biaxially oriented polyamide (PA), co-extruded biaxially oriented polypropylene with ethylene vinyl alcohol copolymer (EVOH) as the core layer, biaxially oriented ethylene vinyl alcohol copolymer (EVOH), and co-extruded biaxially oriented polypropylene coated with polyvinylidene chloride (PVDC). Among these, films made of α-olefin resin can be preferably used, and in particular, polypropylene resin films such as biaxially oriented polypropylene (OPP) are preferred. Furthermore, plastic films may be used that have been coated to improve gas barrier properties or ink receptivity when applying the printing layer described later. Examples of commercially available coated plastic films include K-OPP film and K-PET film. These can be used individually or in combination.

[0119] The thickness of the stretched resin film described above is preferably 10 to 60 μm, more preferably 10 to 40 μm, and even more preferably 10 to 30 μm. When the thickness of the stretched resin film is within this range, the manufacturing of the laminate film becomes easier.

[0120] Furthermore, examples of the unstretched resin films mentioned above include CPP film, nylon film, PET film, and PVC film. Combinations of two or more base materials can also be used.

[0121] Furthermore, the above-mentioned substrate may be formed from biomass polyolefin. The term "biomass polyolefin" refers to a polyolefin resin that uses plant-derived olefins as its monomer raw material. The raw material monomer may contain petroleum-derived monomers, but it does not have to contain 100% plant-derived monomers. Commercially available biomass polyolefins can also be used. Examples of commercially available products include those manufactured by Braschem, such as the SGM9450F, SLL118, SLL118 / 21, SLL218, SLL318, SLH118, SLH218, and SLH0820.

[0122] Furthermore, the substrate to be laminated to the multilayer film of the present invention may be a substrate having a vapor-deposited layer made of inorganic material and / or inorganic oxide provided on the resin film described above. By using a substrate provided with the vapor-deposited layer, barrier properties can be imparted to the laminate of the present invention. The vapor-deposited layer can be formed using known inorganic materials or inorganic oxides by known methods, and its composition and formation method are not particularly limited. Furthermore, the laminate film made of the multilayer film of the present invention may have two or more vapor-deposited films, which may have the same composition or different compositions.

[0123] As the above-mentioned vapor-deposited layer, for example, a vapor-deposited film of an inorganic substance or inorganic oxide such as silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), or yttrium (Y) can be used. Furthermore, vapor-deposited films of inorganic oxides such as silicon oxide and aluminum oxide are transparent.

[0124] The inorganic oxides mentioned above are denoted as MOx (where M represents an inorganic element), such as SiOx and AlOx. The value of x can take on the following ranges: silicon (Si) 0-2, aluminum (Al) 0-1.5, magnesium (Mg) 0-1, calcium (Ca) 0-1, potassium (K) 0-0.5, tin (Sn) 0-2, sodium (Na) 0-0.5, boron (B) 0-1.5, titanium (Ti) 0-2, lead (Pb) 0-1, zirconium (Zr) 0-2, and yttrium (Y) 0-1.5. In the above, when x=0, it represents a completely inorganic element (pure substance), which is not transparent, and when the value of x is at the upper limit of the range, it indicates that it is completely oxidized. Silicon (Si) and aluminum (Al) are preferably used as the vapor-deposited layer. For silicon (Si), x values ​​in the range of 1.0 to 2.0 can be used, and for aluminum (Al), x values ​​in the range of 0.5 to 1.5 can be used.

[0125] The above-mentioned vapor-deposited layer can be formed on the surface of the substrate or the like by methods such as physical vapor deposition (PVD), including vacuum deposition, sputtering, and ion plating, or chemical vapor deposition (CVD), including plasma chemical vapor deposition, thermochemical vapor deposition, and photochemical vapor deposition.

[0126] The thickness of the above-mentioned vapor-deposited layer is not particularly limited as long as the vapor-deposited layer alone can exhibit a certain level of gas barrier function. The preferred thickness range varies depending on the type of metal or metal oxide being deposited, but is preferably 0.05 to 70 nm, more preferably 0.1 to 70 nm, even more preferably 3 to 70 nm, and even more preferably 5 to 60 nm.

[0127] As the above-mentioned metal-deposited film, VM-CPP film, which is obtained by depositing a metal such as aluminum onto a CPP film, and VM-OPP film, which is obtained by depositing a metal such as aluminum onto an OPP film, can be used. Furthermore, examples of the transparent vapor-deposited films mentioned above include films obtained by vapor-depositing silica or alumina onto OPP film, PET film, nylon film, etc. A film with a coating applied to the vapor-deposited layer may be used for purposes such as protecting the inorganic vapor-deposited layer of silica or alumina.

[0128] Furthermore, in applications where transparency is not required, aluminum foil can be used alone or in combination as a barrier layer. However, since the multilayer film of the present invention has excellent anti-fogging properties, it is preferable not to use aluminum foil as a barrier layer in order to exhibit anti-fogging properties.

[0129] Paper can also be used as the base material mentioned above. For example, paper such as coated cardboard, cardstock, ivory paper, Manila cardboard, milk carton paper, cup paper, fine paper, kraft paper, pure white roll paper, glassine paper, parchment paper, Manila cardboard, white cardboard, coated paper, art paper, imitation paper, thin paper, thick paper, polyethylene coated paper, various synthetic papers, and acid-resistant paper can be used for printing on packaging materials for cosmetics, beverages, pharmaceuticals, toys, equipment, etc. Since the multilayer film of the present invention has excellent anti-fogging properties, it is preferable not to use paper as the base material in order to exhibit anti-fogging properties.

[0130] When a laminate is formed by laminating the above-mentioned substrate or a substrate that has been printed or vapor-deposited onto the multilayer film of the present invention, examples of lamination methods include dry lamination, wet lamination, non-solvent lamination, and extrusion lamination. At this time, the layer located between the sealant film and the substrate is called the adhesive layer.

[0131] Examples of adhesives used in the dry lamination described above include solvent-based two-component curing adhesives. A "solvent-type" adhesive refers to a form used in the so-called dry lamination method, in which the adhesive is applied to a substrate, heated in an oven or the like to evaporate the organic solvent in the coating, and then bonded to another substrate. It includes polyisocyanate compositions, polyol compositions, and organic solvents capable of dissolving (diluting) them.

[0132] In the above-mentioned two-component curing adhesive, considering the construction of a sustainable circular society (sustainability), it is preferable to use plant-derived raw materials (biomass raw materials) as raw materials for the polyisocyanate composition or polyol composition. By appropriately using biomass raw materials, the environmental burden can be reduced. Examples of biomass raw materials include castor oil-based polyols such as castor oil, dehydrated castor oil, hydrogenated castor oil (a hydrogenated form of castor oil), and 5-50 molar alkylene oxide adducts of castor oil, as well as aliphatic polybasic acids such as succinic acid, succinic anhydride, glutaric acid, adipic acid, azelaic acid, sebacic acid, and itaconic acid, and alkyl esters and dimer acids of these acids.

[0133] Commercially available adhesives can also be used as the above-mentioned adhesives that utilize biomass raw materials. Commercially available adhesives listed by the Japan Organic Resources Association can be used, such as DIC Dry BM (manufactured by DIC Corporation) and Takenate BM (manufactured by Mitsui Chemicals, Inc.).

[0134] The weight of the above adhesive layer after drying is 0.1 to 10 g / m². 2 Preferably, it is 1-6 g / m 2 It is more preferable that the amount be 2-5 g / m 2 It is even more preferable that this be the case. Furthermore, the thickness of the adhesive layer is preferably 0.1 to 10 μm, more preferably 1 to 7 μm, and even more preferably 2 to 5 μm.

[0135] Furthermore, various adhesives can be used as the adhesive layer, but it is preferable to use a pressure-sensitive adhesive. Examples of pressure-sensitive adhesives include rubber-based adhesives obtained by dissolving polyisobutylene rubber, butyl rubber, or mixtures thereof in organic solvents such as benzene, toluene, xylene, or hexane; or rubber-based adhesives obtained by compounding these with tackifiers such as rosin aviethylene acid ester, terpene-phenol copolymer, or terpene-indene copolymer; or acrylic-based adhesives obtained by dissolving acrylic copolymers with a glass transition temperature of -20°C or lower, such as 2-ethylhexyl acrylate-n-butyl acrylate copolymer or 2-ethylhexyl acrylate-ethyl acrylate-methyl methacrylate copolymer, in an organic solvent.

[0136] By using materials with gas barrier properties as the adhesive or anchor coating agent described later, a laminate film with particularly excellent barrier properties can be obtained. Particularly preferred as an adhesive with excellent gas barrier properties is 3 g / m². 2 The oxygen barrier property of the cured coating film of the adhesive applied with (non-volatile components) is 300 cc / m². 2 Water vapor barrier capacity of 120 g / m² or less per day atm, or 120 g / m². 2 This refers to a value of / day or less that satisfies at least one of the following conditions. Commercially available products include the "PASLIM" series, such as PASLIM VM001 and PASLIM J350X from DIC Corporation, and "Maxive" from Mitsubishi Gas Chemical Company.

[0137] Furthermore, the adhesive layer can also be formed from a thermoplastic resin, and it can be formed by conventionally known methods, such as the melt extrusion lamination method or the sand lamination method. Examples of thermoplastic resins that can be used in the adhesive layer include polyethylene resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE); polypropylene resins such as propylene homopolymers, propylene-α-olefin random copolymers, and propylene-α-olefin block copolymers; norbornene polymers such as ring-opening polymers (COP) of norbornene monomers and norbornene copolymers (COC) obtained by copolymerizing norbornene monomers with olefins such as ethylene, and their hydrogenated products; cyclic polyolefin resins such as vinyl alicyclic hydrocarbon polymers and cyclic conjugated diene polymers; and ethylene Examples include polyethylene-based elastomers such as vinyl acetate copolymer (EVA) and ethylene-α-olefin copolymer, as well as thermoplastic elastomers such as polypropylene-based elastomers and butene-based elastomers; ethylene-based copolymers such as ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), and ethylene-methacrylic acid copolymer (EMAA); and further, ionomers of ethylene-acrylic acid copolymer and ionomers of ethylene-methacrylic acid copolymer. Furthermore, in order to improve the adhesion between layers, acid-modified polyolefin resins, which are obtained by modifying the above-mentioned polyolefin resin with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, or itaconic acid, can also be used. Furthermore, resins obtained by graft polymerization or copolymerization of polyolefin resins with unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, or ester monomers can also be used. These resins can be used individually or in combination of two or more types. Furthermore, it is also preferable to use a polyethylene-based resin that uses biomass-derived ethylene as the monomer unit.

[0138] When laminating adhesive layers by extrusion lamination, an anchor coat layer may be provided on the surface of the layer being laminated, formed by applying an anchor coat agent and drying it. Examples of anchor coating agents include anchor coating agents made from any resin with a heat resistance temperature of 135°C or higher, such as polybutadiene resins, urethane resins, polyisocyanates / polyether polyols, polyethyleneimines, vinyl-modified resins, epoxy resins, polyester resins, alkyl titanates, etc., and anchor coating agents obtained by diluting the above adhesives with an organic solvent. In particular, polyethyleneimine-based anchor coating agents and anchor coating agents obtained by diluting the above adhesive with an organic solvent can be preferably used. Furthermore, a silane coupling agent may be used as an additive, and nitrated cotton may also be used to improve heat resistance.

[0139] When obtaining a laminate of the present invention by laminating the multilayer film of the present invention with a substrate, etc., using an extrusion lamination method or a sand lamination method, the nip roll and chill roll used during lamination may be replaced with embossing rolls to apply embossing to the surface on the sealing layer side.

[0140] Laminates obtained by lamination are typically subjected to an aging treatment, where the film roll, wound from the laminate, is stored in an environment of approximately 40°C for 1 to 4 days to accelerate the curing of adhesives and obtain high adhesive strength. The multilayer film of the present invention maintains stable anti-fogging properties even after such an aging treatment.

[0141] The laminate of the present invention may further include a printed layer between the multilayer film of the present invention and the substrate. The printing layer is a layer formed by liquid printing ink to create a desired pattern on the substrate in order to impart aesthetic appeal, various information about the contents, and functionality. The printed layer is formed by printing gravure printing ink or flexographic printing ink (hereinafter referred to as liquid printing ink) containing a binder resin and a colorant, active energy ray curing ink, or inkjet ink. The printed layer may be a single layer or may consist of multiple printed layers. If there are multiple printing layers, the liquid printing ink used for each printing layer may be the same, or it may have the same composition but with different colorants, or it may have different compositions. Furthermore, printing using two types of printing inks in combination, such as liquid printing ink and inkjet ink, is also acceptable. In cases where there are multiple printing layers, for example, the printed material may have a first printing layer formed from a printing ink containing a coloring agent, a second white printing layer formed from a liquid ink containing a white pigment as a coloring agent, and a third white printing layer, in this order. The first printing layer can form a pattern using a coloring agent, while the second white printing layer and the third printing layer, formed with a liquid ink containing white pigment, can be used as the background for the pattern. If the second or third printing layer is an overprint varnish, it does not need to contain a coloring agent.

[0142] The above-mentioned liquid printing inks are used as gravure printing inks and flexographic printing inks, and are broadly classified into organic solvent-type liquid printing inks, which use organic solvents as the main solvent, and water-based liquid printing inks, which use water as the main solvent. The printing layer is preferably a general-purpose organic solvent-based liquid printing ink.

[0143] The above-mentioned organic solvent-type liquid printing ink is obtained by dispersing a mixture containing pigment, binder resin, organic solvent medium, dispersant, defoamer, etc., in a disperser to obtain a pigment dispersion. The obtained pigment dispersion is then mixed by adding a resin, an aqueous medium, and, if necessary, additives such as a leveling agent, and stirring. Dispersion machines commonly used in the production of gravure and flexographic printing inks include bead mills, Eiger mills, sand mills, gamma mills, and attritors.

[0144] Examples of the binder resins mentioned above include cellulose-based resins such as nitrated cotton, cellulose acetate propionate (CAP) and cellulose acetate butyronate (CAB), polyamide resins, polyurethane resins, acrylic resins, vinyl chloride-vinyl acetate copolymer resins, chlorinated polypropylene resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, polyvinyl chloride resins, vinyl chloride-acrylic copolymer resins, polyester resins, alkyd resins, rosin-based resins, rosin-modified maleic acid resins, ketone resins, cyclic rubbers, chlorinated rubbers, butyral, and petroleum resins. Among these, polyurethane resin is particularly suitable.

[0145] As the polyurethane resin mentioned above, a polyurethane resin obtained by polymerizing a polyol and a polyisocyanate is preferred. Furthermore, it is preferable that the polyol is a polyester polyol. Furthermore, if necessary, polyurethane resins may be synthesized in combination with polyether polyols, polyester polyols, general-purpose polyols other than polyether polyols, chain extenders, and end-capping agents. Furthermore, the polyol may be reacted with a polyisocyanate to form a urethane prepolymer having isocyanate groups at its ends, and this prepolymer may be reacted with a polyamine compound to synthesize a polyurethane resin. The polyurethane resin may be used alone in the liquid ink, or multiple polyurethane resins may be used in combination.

[0146] Examples of the above-mentioned pigments include inorganic pigments and organic pigments used in general inks, paints, and recording materials. Examples of such organic pigments include soluble azo pigments, insoluble azo pigments, azo pigments, phthalocyanine pigments, halogenated phthalocyanine pigments, anthraquinone pigments, anthancerone pigments, dianthaquinonyl pigments, anthrapyrimidine pigments, perylene pigments, perinone pigments, quinacridone pigments, thioindigo pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, azomethine azo pigments, flavanthrone pigments, diketopyrrolopyrrole pigments, isoindoline pigments, indanthrone pigments, and carbon black pigments. Other examples include carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, chromophthal yellow, chromophthal red, phthalocyanine blue, phthalocyanine green, dioxazine violet, quinacridone magenta, quinacridone red, indanthrone blue, pyrimidine yellow, thioindigobordeaux, thioindigomagenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, and daylight fluorescent pigments. Furthermore, both untreated and acid-treated pigments can be used.

[0147] Examples of such inorganic pigments include white inorganic pigments such as titanium dioxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, lithopone, antimony white, and gypsum. Among inorganic pigments, the use of titanium dioxide is particularly preferred. Titanium dioxide is white in color and is preferred in terms of coloring ability, opacity, chemical resistance, and weather resistance. From the viewpoint of printing performance, it is preferable that the titanium dioxide is treated with silica and / or alumina. Examples of inorganic pigments other than white include aluminum particles, mica, bronze powder, chrome vermilion, lead yellow, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, and zircon. Aluminum is available in powder or paste form, but it is preferable to use it in paste form for ease of handling and safety. Whether to use leafing or non-leafing aluminum is selected appropriately from the viewpoint of brightness and density.

[0148] There are no particular restrictions on the above-mentioned organic solvents, but examples include aromatic hydrocarbon organic solvents such as toluene, xylene, Solvesso #100, and Solvesso #150; aliphatic hydrocarbon organic solvents such as hexane, methylcyclohexane, heptane, octane, and decane; and various ester-based organic solvents such as methyl acetate, ethyl acetate, isopropyl acetate, n-propyl acetate, butyl acetate, amyl acetate, ethyl formate, and butyl propionate. Furthermore, examples of water-miscible organic solvents include alcohol-based solvents such as methanol, ethanol, propanol, butanol, and isopropyl alcohol; ketone-based solvents such as acetone, methyl ethyl ketone, and cycloxanone; and glycol ether-based organic solvents such as ethylene glycol (mono, di)methyl ether, ethylene glycol (mono, di)ethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono, di)methyl ether, diethylene glycol (mono, di)ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono, di)methyl ether, propylene glycol (mono, di)methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol (mono, di)methyl ether. These can be used individually or in combination of two or more types.

[0149] Furthermore, from the viewpoint of workplace hygiene during printing and the harmfulness of packaging materials, it is more preferable to use ethyl acetate, propyl acetate, isopropanol, n-propanol, etc., and to avoid using aromatic solvents such as toluene and ketone-based solvents such as methyl ethyl ketone. Among these, a mixture of isopropyl alcohol / ethyl acetate / methoxypropanol is more preferred from the viewpoint of polyurethane resin solubility. Additionally, glycol ethers may be added to adjust the drying time, provided they make up less than 10% by mass of the total ink volume.

[0150] The above-mentioned organic solvent-based liquid printing ink exhibits excellent adhesion to various substrates and can be used for printing on paper, synthetic paper, thermoplastic resin films, plastic products, steel plates, etc. It is useful as an ink for gravure printing using gravure printing plates made by electronic engraving or the like, or for flexographic printing using flexographic printing plates made by resin plates or the like. The film thickness of the liquid printing ink formed by gravure printing or flexographic printing using the above-mentioned organic solvent-type liquid printing ink is preferably 0.1 to 10 μm, more preferably 1 to 5 μm, and even more preferably 1 to 3 μm. Furthermore, the weight of the printed layer after drying is 0.1 to 10 g / m². 2 Preferably, it is 1-5 g / m 2 It is more preferable that the amount be 1-3 g / m 2 It is even more preferable that this be the case.

[0151] In the above-mentioned liquid printing inks, it is preferable to use liquid printing inks made from plant-derived raw materials (biomass raw materials), taking into consideration the construction of a sustainable circular society that should develop in a sustainable manner. Examples of plant-derived raw materials include cellulose acetate propionate resin and nitrated cotton resins, polyamide resins using dimer acids or polymerized fatty acids derived from natural oils such as soybean oil, palm oil, and rice bran oil, as well as polycarboxylic acids such as succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dimer acid, glutaric acid, and malic acid, as well as polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, pentylene glycol, 1,10-dodecanediol, dimer ol, and isosorbide, and polyisocyanates such as 1,5-pentamethylene diisocyanate and dimer isocyanate. Biomass polyurethanes synthesized from these plant-derived raw materials include rosin resin, dammar resin, and polylactic acid.

[0152] Liquid printing inks using the above-mentioned plant-derived raw materials can also be commercially available. Commercially available inks and other materials listed by the Japan Organic Resources Association can be used, such as Finart BM (manufactured by DIC Corporation), LP Bio Series (manufactured by Toyo Ink Co., Ltd.), Bellflora (manufactured by Sakata Inx Corporation), and NB300 BP Series (manufactured by Dainichi Seika Kogyo Co., Ltd.).

[0153] The above-mentioned printed layer may be printed on another substrate using a so-called reverse printing method, and then the substrate and the multilayer film of the present invention may be laminated by methods such as dry lamination, sand lamination, or extrusion lamination. The extrusion lamination method is preferable because it reduces the manufacturing load, as it allows the manufacturing of the multilayer film of the present invention, lamination with the substrate, and, if applicable, embossing of the seal layer (A) of the multilayer film to be carried out in a single step. Additionally, anchor coat varnish or overcoat varnish may be used.

[0154] <Packaging material> The multilayer film or laminate of the present invention is not particularly limited in its use, but can be used as packaging material for food, pharmaceuticals, industrial parts, general merchandise, magazines, etc., and is particularly suitable for use as lid material for food packaging containers. In particular, it is preferable that the outermost layer of the packaging container (the part that adheres to the seal layer (A) of the multilayer film of the present invention) contains a polyester resin, from the viewpoint of balancing ease of opening and seal strength. Furthermore, because it exhibits excellent anti-fogging properties, it can be suitably used for packaging foods containing a lot of moisture, and is preferably used as lid material for food packaging containers. The packaging material of the present invention may also be a packaging bag made by forming a bag from the laminate of the present invention.

[0155] Preferably, the above-mentioned packaging bag is a packaging bag formed by overlapping and sealing the sealing layers (A) of the multilayer film or laminate of the present invention, or by overlapping and sealing the outermost layer and the sealing layer (A). For example, two of the multilayer films can be cut to the desired size of a packaging bag, overlapped and sealed on three sides to form a bag, and then the contents can be filled from the unsealed side and sealed to create a sealed packaging bag. Furthermore, it is also possible to form a packaging bag by sealing the ends of a roll of film into a cylindrical shape using an automatic packaging machine, and then sealing the top and bottom.

[0156] Furthermore, the multilayer film or laminate of the present invention can also be used to form packaging bags and packaging containers by overlapping and sealing a sealing layer (A) with another sealable film. In this case, the other film can be a film with relatively low mechanical strength, such as LDPE or EVA. Alternatively, a laminate film can be used, which is made by bonding a film such as LDPE or EVA with a stretched film with relatively good tear resistance, such as biaxially oriented polyethylene terephthalate film (OPET) or biaxially oriented polypropylene film (OPP).

[0157] (Sealing method) The multilayer film or laminate of the present invention has sealing properties and can form a package by sealing. The sealing strength of the multilayer film or laminate of the present invention can be appropriately adjusted depending on the intended use, but for example, when the multilayer film or laminate of the present invention is heat-sealed to an amorphous polyethylene terephthalate (A-PET) sheet (softening point 77°C, crystallization temperature 126°C) at a temperature of 140°C and a pressure of 0.2 MPa for 1.0 second, a 15 mm wide test piece is cut out, and when peeled in the 180-degree direction at a tensile speed of 300 mm / min in a constant temperature room of 23°C and 50% RH, the maximum load is preferably 3 N / 15 mm or more, more preferably 5 N / 15 mm or more, and even more preferably 6 N / 15 mm or more. Furthermore, the upper limit of the maximum load is preferably less than 20 N / 15 mm, and more preferably less than 15 N / 15 mm. This peel strength makes it difficult for the multilayer film to peel or fall off, and particularly facilitates easy opening. Furthermore, the multilayer film of the present invention can be sealed not only by heat sealing but also by ultrasonic sealing. There are no particular limitations on the ultrasonic sealing method, and known ultrasonic sealing methods or methods using known ultrasonic sealing devices can be appropriately selected depending on the purpose.

[0158] In packaging bags using the multilayer film or laminate of the present invention, it is preferable to form arbitrary tear-initiating sections such as V-notches, I-notches, perforations, or micropores in the seal portion in order to weaken the initial tear strength and improve ease of opening. [Examples]

[0159] Next, the present invention will be described in more detail with reference to examples and comparative examples. Hereinafter, unless otherwise specified, "parts" refers to parts by mass.

[0160] <Polyester resin> The composition of the polyester resin used is shown below. Polyester 1: Terephthalic acid / Isophthalic acid / Ethylene glycol = 30 / 10 / 40 (mol ratio) [Glass transition temperature: 72°C] Polyester 2: Terephthalic acid / Adipic acid / 1,4-Butanediol = 24.5 / 25.5 / 50 (mol ratio) [Glass transition temperature: -35°C, Melting point: 120°C] Polyester 3: Terephthalic acid / Isophthalic acid / Polytetramethylene ether glycol / 1,4-Butanediol = 33.3 / 16.7 / 33.3 / 16.7 [Glass transition temperature: -70°C, Melting point: 127°C] Polyester 4: Terephthalic acid / 1,4-butanediol / polytetramethylene ether glycol = 50 / 35 / 15 [Glass transition temperature: -32°C, melting point: 165°C]

[0161] <Preparation of an anti-fogging masterbatch based on polyester resin> (Preparation Example 1) 90 parts of polyester 1 and 10 parts of nonionic surfactant 1 (diglycerin fatty acid ester, HLB:6) were melt-kneaded and granulated to obtain anti-fogging agent masterbatch pellet 1 (hereinafter referred to as anti-fogging agent MB1). (Preparation Example 2) 90 parts of polyester 1 and 10 parts of nonionic surfactant 2 (diglycerin fatty acid ester, HLB: 7.5) were melt-kneaded and granulated to obtain anti-fogging agent masterbatch pellets 2 (hereinafter referred to as anti-fogging agent MB2).

[0162] (Example 1) As the sealing layer (A), an antiblocking agent 2 (CAS number 1344-00-9), polyester 1, polyester 2, antifogging agent MB1, and polyethylene glycol 1 (freezing point 37°C) were used, and a mixture was used in the ratio of polyester 1 / polyester 2 / nonionic surfactant 1 / polyethylene glycol 1 / antiblocking agent 2 = 65.5 parts / 30 parts / 1.75 parts / 1.75 parts / 1 part. Linear low-density polyethylene (density 0.93 g / cm³) is used as the laminate layer. 3Using a melt flow rate of 6g / 10min (230℃); hereinafter referred to as LLDPE, polyethylene-based anti-fogging agent MB [ESR-793 manufactured by Riken Vitamin Co., Ltd.] and anti-blocking agent 1 (CAS number 1344-01-0), a mixture of LLDPE / anti-fogging agent MB / anti-blocking agent 1 = 96.5 parts / 2.5 parts / 1 part was used. Using LLDPE as the intermediate layer, The resin layer (B) is an acid-modified ethylene-propylene-butene copolymer [acid modification amount: 2.9 parts by mass, density: 0.89 g / cm³]. 3 Using a mixture of acid-modified polyolefin (hereinafter referred to as acid-modified polyolefin) and polyester 3, with a ratio of acid-modified polyolefin / polyester 3 = 65 parts / 35 parts, Resin was supplied to the extruder for the seal layer (A) (40 mm diameter), the extruder for the resin layer (B) (40 mm diameter), the extruder for the intermediate layer (50 mm diameter), and the extruder for the laminate layer (50 mm diameter). Using a co-extrusion method, the laminate layer / intermediate layer / resin layer (B) / seal layer (A) were extruded from the T-die at an extrusion temperature of 230°C so that the thicknesses of each layer were 9 μm / 12 μm / 6 μm / 3 μm. The film was cooled with a water-cooled metal cooling roll at 30°C, and corona discharge treatment was performed to achieve a wetting tension of 40 mN / m in the laminate layer. The film was then wound onto a roll and aged in a 40°C aging chamber for 36 hours to obtain the multilayer film of Example 1 with a total thickness of 30 μm.

[0163] (Examples 2-19) Films for Examples 2 to 19 were prepared in the same manner as in Example 1, except for the configurations shown in Tables 1 and 2.

[0164] (Comparative Examples 1-2) The films of Comparative Examples 1 and 2 were prepared in the same manner as in Example 1, except for the configuration shown in Table 2.

[0165] In Tables 1 and 2, the components other than polyester 1-4 are as follows: LLDPE: Linear low-density polyethylene (density 0.93 g / cm³) 3 (Melt flow rate 6g / 10 minutes (230℃)) HDPE: High-density polyethylene (density 0.95 g / cm³)3 Melt flow rate 16g / 10 minutes (190℃) Anti-fogging agent MB: Polyethylene-based anti-fogging agent masterbatch [ESR-793, manufactured by Riken Vitamin Co., Ltd.] Antiblocking agent 1: CAS number 1344-01-0 Acid-modified polyolefin: Acid-modified ethylene-propylene-butene copolymer (acid modification amount 2.9 parts by mass, density 0.89 g / cm³) 3 ) Nonionic surfactant 1: Diglycerin fatty acid ester (HLB: 6) Nonionic surfactant 2: Diglycerin fatty acid ester (HLB: 7.5) Polyethylene glycol 1: Freezing point 37°C Polyethylene glycol 2: Freezing point 45°C Polyethylene glycol 3: Freezing point 51°C Polyethylene glycol 4: Freezing point 55°C Antiblocking agent 2: CAS number 1344-00-9 Recovered items: Film edges generated during the manufacturing of the multilayer film of the present invention.

[0166] (Evaluation of the stability of anti-fogging properties against aging) A 12 μm thick biaxially oriented polyester film was laminated to the laminate layer side of the obtained multilayer film using a dry lamination adhesive to create an evaluation laminate film. For this dry lamination, a two-component curing adhesive (polyester adhesive "LX500" and curing agent "KW-75") manufactured by DIC Corporation was used. The prepared laminate film was subjected to aging treatment by overlapping one seal layer (A) and one stretched resin film, placing a 7.5 N weight on top to press the laminate films together, and storing it at 40°C for 24 or 96 hours. The film is made of amorphous polyethylene terephthalate (hereinafter referred to as A-PET), has a 5 mm wide, smooth flange, is 88 mm square with sides of 80 cm³, and a capacity of 80 cm³. 330 ml of 40°C water was placed in a container, and the seal layer (A) side of the resulting laminate film was aligned with the container and heat-sealed using a cup sealer. The container was then stored at 3°C, and the anti-fogging effect was visually confirmed after 3 hours. The anti-fogging effect was compared between a 24-hour aging treatment and a 96-hour aging treatment, and the stability of the anti-fogging properties against the aging treatment was evaluated according to the following criteria. (Stability evaluation criteria for anti-fogging properties against aging treatment) ◎: Anti-fog properties are further improved after 96 hours of aging treatment. ○: No change in anti-fogging properties even after 96 hours of aging treatment. △: Anti-fog performance slightly deteriorated after 96 hours of aging. ×: The anti-fog properties deteriorated significantly after 96 hours of aging treatment. ××: Poor anti-fogging performance after 24-hour aging treatment

[0167] (Method for evaluating the peeling surface (film breakability) after cup sealing) In the A-PET containers whose anti-fogging properties were measured as described above, a peel test was conducted using a 45° peel test fixture (manufactured by Imada Co., Ltd.) with the peel angle fixed at 45°. The appearance of the containers after peeling was visually inspected and evaluated according to the following criteria. (Membrane-breaking ability evaluation criteria) ◎: Even when opened at 30 mm / min, no film residue is left behind. ○: Even when opened at 100 mm / min, no film residue is generated. △: No film residue is produced even when opened at a rate of 250 mm / min. ×: Residual film of the sealing layer (A) occurred.

[0168] (Evaluation of heat seal strength) The sealing layer (A) side of the laminate film described above was aligned with an A-PET sheet (softening point 77°C, crystallization temperature 126°C). Using a precision heat sealer (manufactured by Tester Industries), the sheet was heat-sealed for 1.0 second at a temperature of 140°C and a pressure of 0.2 MPa with a 10 mm wide sealing bar. After cooling, a 15 mm wide test piece was cut from the heat-sealed sample and peeled in a 180-degree direction at a constant temperature of 23°C and 50% RH using a universal tensile testing machine (manufactured by A&D Co., Ltd.) at a tensile speed of 300 mm / min to measure the maximum load. (Unit: N / 15 mm) (Heat seal strength evaluation criteria) ○: 6N or higher / 15mm △: 4~6N / 15mm ×: 4N or less / 15mm

[0169] (Hayes's evaluation) The haze of the multilayer films in the examples and comparative examples was measured using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd.) in accordance with JIS K 7105:1981. ◎: 8% or less ○: 8-15% ×: 15% or more

[0170] [Table 1]

[0171] [Table 2]

[0172] As is clear from Tables 1 and 2 above, the multilayer films of the present invention in Examples 1 to 14 were able to achieve suitable anti-fogging properties, film breakability, and heat seal strength after aging treatment. Furthermore, Examples 6 to 14, which used polyalkylene glycol with a solidification point of 40°C or higher, showed particularly excellent stability of anti-fogging properties against aging treatment. On the other hand, the multilayer film of Comparative Example 1, which did not contain polyalkylene glycol in the sealing layer (A), had good film breakability and heat seal strength, but poor anti-fogging properties after 24 hours of aging treatment. Similarly, the multilayer film of Comparative Example 2, which did not contain polyalkylene glycol in the sealing layer (A), showed deterioration in anti-fogging properties after 96 hours of aging treatment.

Claims

1. It includes a sealing layer (A) and a resin layer (B) adjacent to the sealing layer (A), The sealing layer (A) comprises a polyester resin (a), an anti-fogging agent, and polyalkylene glycol. The resin layer (B) comprises an acid-modified polyolefin and a polyester resin (b), The glass transition temperature of the polyester resin (b) is 45°C or lower. Multilayer film.

2. The multilayer film according to claim 1, wherein the freezing point of the polyalkylene glycol is 40°C or higher.

3. The sealing layer (A) comprises polyester resin (a1) and polyester resin (a2) as the polyester resin (a), The multilayer film according to claim 1, wherein the glass transition temperature of the polyester resin (a1) is 60 to 140°C, and the glass transition temperature of the polyester resin (a2) is 45°C or lower.

4. The multilayer film according to claim 1, wherein the total thickness is 20 μm or more and 100 μm or less.

5. The multilayer film according to claim 1, wherein the content of polyalkylene glycol in the sealing layer (A) is 0.1 to 5.0% by mass.

6. The multilayer film according to claim 1, wherein the mass ratio of the acid-modified polyolefin to the polyester resin (b) in the resin layer (B) is 45:55 to 95:

5.

7. The multilayer film according to claim 1, wherein the multilayer film further includes a laminate layer.

8. A laminate having a multilayer film according to any one of claims 1 to 7.

9. A packaging material using the laminate described in claim 8.

10. The packaging material according to claim 9, which is a lid material for a food packaging container.

11. A food packaging container having the packaging material described in claim 10 as a lid material, wherein the portion of the food packaging container that adheres to the lid material contains a polyester resin.

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