CN110603290A

CN110603290A - Film

Info

Publication number: CN110603290A
Application number: CN201880030760.3A
Authority: CN
Inventors: 刘琛; 矢野贵明; 桑崎直人
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2017-05-11
Filing date: 2018-05-09
Publication date: 2019-12-20
Also published as: WO2018207824A1; JPWO2018207824A1; TW201903008A

Abstract

A film which comprises a base material layer and a sealant layer and has a thickness of 20 ~ μm, one surface layer of the film being the base material layer and the other surface layer being the sealant layer, the sealant layer comprising a resin composition and having a thickness of 5 ~ 100 μm, the crystal index of the surface of the sealant layer on the film surface being 0.680 ~ 0.900, wherein when the film is heat-sealed to an adherend (X) under conditions of a temperature of 160 ℃, a time of 1 second, a seal strip width of 10mm, and a pressure of 450kPa in a state where the sealant layer on the film surface is brought into contact with the adherend (X), the ratio of the thickness of a portion formed by elution and solidification of the resin composition of the sealant layer from the heat-sealed portion to the non-heat-sealed portion to the thickness of the sealant layer in the non-heat-sealed portion is 1.80 ~.20.

Description

Film

Technical Field

The present invention relates to a membrane and a lid comprising the membrane.

Background

Patent document 1 describes a laminated resin film having a seal layer formed by blown film forming, the seal layer including an ethylene copolymer obtained by copolymerizing ethylene and a vinyl alkyl ester and two ethylene- α -olefin copolymers having different degrees of crystallinity.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 6-212036.

Disclosure of Invention

Problems to be solved by the invention

The invention provides a film and a lid, which can inhibit the blocking of films overlapped in a mode that sealing layers on the surfaces of the films are contacted with each other, and have the sealing property and easy-to-open property when the sealing layers on the surfaces of the films are heat-sealed on a polypropylene adherend and a polystyrene adherend.

Means for solving the problems

The present invention provides the following [1] ~ [8 ].

[1] A film which comprises a base layer and a sealant layer and has a thickness of 20 μm or more and 150 μm or less, one surface layer of the film being the base layer and the other surface layer being the sealant layer, the sealant layer comprising a resin composition, and has a thickness of 5 to 100 [ mu ] m, and a crystal index [ D730/D720] of the surface of the sealing layer on the film surface, measured by a multiple reflection ATR-IR method, of 0.680 to 0.900, in the case where the film is heat-sealed to the adherend (X) under the conditions of a temperature of 160 ℃ for 1 second, a seal strip width of 10mm and a pressure of 450kPa in a state where the seal layer on the film surface is in contact with the adherend (X), the ratio of the thickness of the portion of the sealing layer formed by the resin composition dissolving out from the heat-sealed portion to the non-heat-sealed portion and curing to the thickness of the sealing layer in the non-heat-sealed portion is 1.80 to 2.20.

Adherend (X): an adherend comprising an impact-resistant polystyrene having a melt flow rate of 3.0g/10 min or more and 4.0g/10 min or less and a Vickers softening temperature of 95 ℃ or more and 100 ℃ or less, and having a thickness of 350 [ mu ] m or more and 550 [ mu ] m or less.

[2] The film according to [1], wherein [ D730/D720] is 0.680 or more and 0.750 or less.

[3] The film according to [1] or [2], wherein when the film is heat-sealed to an adherend (X) under conditions of a temperature of 160 ℃, a time of 1 second, a seal strip width of 10mm, and a pressure of 450kPa, a ratio of a thickness of a portion formed by dissolution and solidification of the resin composition of the seal layer from the heat-sealed portion to the non-heat-sealed portion to a thickness of the seal layer of the non-heat-sealed portion is 1.85 or more and 2.20 or less.

[4] A resin composition comprising the following components (A), (B) and (C), wherein the total amount of the components (A), (B) and (C) is 100% by weight,

the content of the unsaturated ester-based monomer unit and the content of the component (C) in the entire polymer in the resin composition are 3% by weight or more and 10% by weight or less, and 2% by weight or more and 10% by weight or less, respectively.

Component (A): the density was 850kg/m³Above 940kg/m³The following ethylene polymers

Component (B): ethylene-unsaturated ester copolymer comprising ethylene-based monomer unit and unsaturated ester-based monomer unit

Component (C): alicyclic saturated hydrocarbon resins.

[5] The resin composition according to [4], wherein the component (A) has a melt flow rate of 3g/10 min or less as measured at 190 ℃ under a load of 21.18N in accordance with JIS K7210.

[6] The resin composition according to [4] or [5], which further contains an antiblocking agent.

[7] A film comprising a layer comprising the resin composition according to any one of [4] ~ [6 ].

[8] A film comprising a layer comprising the resin composition according to any one of [4] ~ [6] and a layer comprising a vinyl polymer,

at least one surface layer among 2 surface layers of the film is a layer containing the resin composition described in [4] ~ [6 ].

[9] A film comprising a layer comprising the resin composition according to any one of [4] ~ [6] and a layer containing no vinyl polymer,

[10] A lid comprising the film of any one of [1] ~ [3] and [7] ~ [9 ].

Effects of the invention

According to the present invention, it is possible to provide an easy-to-open film and a lid which can suppress sticking between films stacked so that sealing layers on film surfaces are brought into contact with each other and which have sealability and easy-to-open property when the sealing layers on film surfaces are heat-sealed to a polypropylene adherend and a polystyrene adherend.

Detailed Description

In the present specification, the density is a value measured by the method A according to the method defined in JIS K7112-1980 after annealing as described in JIS K6760-1995. In the present specification, the melt flow rate (hereinafter sometimes referred to as MFR) is a value measured under the conditions of a temperature of 190 ℃ and a load of 21.18N in accordance with JIS K7210.

The film of the present invention is a film comprising a base layer and a sealant layer. The film of the present invention is an easy-open film.

The crystal index of the surface of the sealant layer on the film surface (hereinafter sometimes referred to as "D730/D720") was measured by the following method.

The infrared absorption spectrum of the sealing layer on the film surface was measured by a multiple reflection ATR-IR method. At 725cm of the measured infrared absorption spectrum^-1Above and 735cm^-1In the following range, the height of the peak having the largest height from the base line is denoted as D730. At 715cm of the measured infrared absorption spectrum^-1Above and less than 725cm^-1The height of the peak whose height from the base line is the largest is denoted as D720. The crystal index of the surface of the sealing layer on the film surface was determined by dividing D730 by D720.

At 715cm^-1Above and less than 725cm^-1The peak whose height in the region of (a) is maximized is a peak derived from a crystalline component and an amorphous component of the resin composition contained in the sealing layer. At 725cm^-1Above and 735cm^-1The peak having the largest height in the following region is a peak derived from a crystalline component of the resin composition contained in the sealing layer.

The smaller the value of D730/D720, the more amorphous components in the resin composition contained in the seal layer on the film surface, and therefore the seal layer on the film surface is sticky, and therefore, when the seal layers on the film surfaces are overlapped so as to be in contact with each other, blocking of the seal layers on the film surfaces is likely to occur.

The value of D730/D720 is preferably 0.690 or more, more preferably 0.700 or more. In the case where the value of D730/D720 is less than 0.680, sticking of the seal layers to each other easily occurs.

The value of D730/D720 is preferably 0.850 or less, more preferably 0.800 or less. When the value of D730/D720 exceeds 0.900, the sealing property of the heat-sealed film may be lowered.

The value of D730/D720 is preferably 0.690 or more and 0.850 or less, more preferably 0.700 or more and 0.800 or less.

"scraping (Poly-Ball)" means: when the film is heat-sealed to an adherend, a portion formed by the resin composition of the sealing layer dissolving out from the heat-sealed portion to the non-heat-sealed portion and curing in the vicinity of the heat-sealed portion is a portion having a larger thickness than the sealing layer of the non-heat-sealed portion. The thicker the thickness of the "gathers", the higher the heat seal strength becomes.

The film was heat-sealed to the adherend (X) under conditions of a temperature of 160 ℃ for 1 second, a seal strip width of 10mm, and a pressure of 450kPa in a state where the seal layer on the film surface was brought into contact with the adherend (X) described below, to obtain a sample. The obtained sample was cut in the thickness direction of the film in parallel with the heat-seal width using a cryomicrotome to obtain a test piece. The cut surface of the obtained test piece was set as an observation surface. The observation surface was measured by a phase difference microscope to obtain an image. Using the obtained image, the thickness of the gather (hereinafter sometimes referred to as T) is measured₁) And the thickness of the sealing layer of the non-heat-sealed portion (hereinafter sometimes referred to as "T")₀)。

The term "high impact polystyrene" as used herein means a polystyrene having a Charpy impact strength of 9 ~ 13kJ/m²The impact-resistant polystyrene of (1). Charpy impact strength was measured in accordance with JIS K7111.

The non-heat-seal-sealed portion means: the sealing layer on the film surface is not bonded to the adherend (X). T is₀Thickness of the sealing layer on the film surface of the non-heat-sealed portion.

T₁The measurement was carried out by the following method.

(1) The end point of the bonding part between the sealing layer and the adherend is denoted as P₁。

(2) Obtaining tangent lines L and P of boundary line between the sealing layer and the layer except the adherend₁The shortest distance of (c).

(3) T represents the thickness of the sealing layer having the shortest distance and a thickness greater than that of the non-heat-sealed portion among the distances obtained in (2)₁。

The ratio of the thickness of the gathered portion to the thickness of the sealing layer of the non-heat-sealed portion (hereinafter sometimes referred to as T)₁/T₀) Preferably 1.83 to 2.20, more preferably 1.85 to 218 or less.

At T₁/T₀If the amount is less than 1.80, the sealing property of the film at the time of heat sealing is lowered.

The thickness of the film is preferably 25 μm or more and 120 μm or less, more preferably 30 μm or more and 100 μm or less. The thickness of the film was measured by performing thin-cutting along the thickness direction of the film using a cryomicrotome, and observing the cross section of the resulting test piece using an optical microscope.

(sealing layer)

The sealing layer of the film comprises, for example, a resin composition containing components (a), (B) and (C).

Component (C): alicyclic saturated hydrocarbon resins.

Relative to the total weight of the resin components contained in the resin composition being 100 wt%,

the total content of the components (a), (B), and (C) is preferably 70% by weight or more, more preferably 80% by weight or more, further preferably 90% by weight or more, and particularly preferably 95% by weight or more.

< ingredient (A) >

The density of the component (A) is preferably 880 ~ 930kg/m³More preferably 910 ~ 928kg/m³。

The component (A) is substantially free of unsaturated ester-based monomer units. The content of the unsaturated ester-based monomer unit in the component (a) is preferably less than 5% by weight, more preferably less than 2% by weight. The component (A) does not substantially contain a monomer unit based on an alicyclic saturated hydrocarbon. The content of the alicyclic saturated hydrocarbon-based monomer unit in the component (a) is preferably 5% by weight or less, and preferably less than 2% by weight or less.

The MFR of the component (A) is preferably 0.1 ~ 30g/10 min, more preferably 0.2 ~ 15g/10 min, and still more preferably 0.3 ~ 3g/10 min.

As the component (A), there may be mentioned one having a density of 850kg/m³Above and940kg/m³the following high-pressure-method low-density polyethylene (hereinafter sometimes referred to as "component (A-1)") and the polyethylene had a density of 850kg/m³Above 940kg/m³The following ethylene- α -olefin copolymer (hereinafter sometimes referred to as "component (A-2)").

The resin composition may contain only 1 component (a), or may contain 2 or more components. The resin composition may contain only 1 component (A-2), or may contain 2 or more components. The resin composition may contain only the component (A-1), may contain only the component (A-2), and may contain both the component (A-1) and the component (A-2).

The high-pressure low-density polyethylene is an ethylene polymer produced by a high-pressure radical polymerization method, and examples of the method for producing the high-pressure low-density polyethylene include a method of continuously polymerizing ethylene in a pressure-resistant polymerization reactor under a pressure of 1000 ~ 2500 atm and at a temperature of 150 ~ 300 ℃ by using oxygen or an organic peroxide as a polymerization initiator.

The MFR of the component (A-1) is preferably 0.1 ~ 30g/10 min, more preferably 0.2 ~ 15g/10 min, and still more preferably 0.3 ~ 3g/10 min.

The density of the component (A-1) is preferably 910 ~ 930kg/m³More preferably 915 ~ 928kg/m³More preferably 920 ~ 925kg/m³。

The component (A-2) is a copolymer comprising an ethylene-based monomer unit and a monomer unit based on an alpha-olefin having 3 or more carbon atoms, and the component (A-2) is preferably a copolymer comprising an ethylene-based monomer unit and a monomer unit based on at least 1 monomer selected from alpha-olefins having 4 ~ 20 carbon atoms.

The α -olefin includes 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-dimethyl-1-butene, 4-methyl-1-pentene and 1-octene, and the α -olefin is preferably an α -olefin having a carbon number of 4 ~ 8, and more preferably 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene from the viewpoint of easiness of obtaining.

The component (A-2) may contain only 1 kind of monomer unit based on an alpha-olefin, or may contain 2 or more kinds.

Ingredient (a-2) may comprise monomer units based on ethylene and alpha-olefin monomers. Examples of the monomer other than ethylene and α -olefin include conjugated dienes such as butadiene and isoprene; non-conjugated dienes such as 1, 4-pentadiene; acrylic acid and methacrylic acid.

The content of the ethylene-based monomer unit in the component (A-2) is preferably 80 ~ 97% by weight relative to 100% by weight of the total weight of the component (A-2). The content of the α -olefin-based monomer unit relative to 100% by weight of the total weight of the component (A-2) is preferably 3 ~ 20% by weight.

Examples of the component (A-2) include an ethylene-1-butene copolymer, an ethylene-1-hexene copolymer, an ethylene-4-methyl-1-pentene copolymer, an ethylene-1-octene copolymer, an ethylene-1-butene-1-hexene copolymer, an ethylene-1-butene-4-methyl-1-pentene copolymer, an ethylene-1-butene-1-octene copolymer and an ethylene-1-hexene-1-octene copolymer, and preferably an ethylene-1-hexene copolymer and an ethylene-1-butene-1-hexene copolymer.

The MFR of the component (A-2) is preferably 0.1 ~ 30g/10 min, more preferably 0.2 ~ 15g/10 min, and still more preferably 0.3 ~ 3g/10 min.

The density of the component (A-2) is preferably 880 ~ 930kg/m³More preferably 910 ~ 925kg/m³。

As the polymerization method of the component (A-2), bulk polymerization, solution polymerization, slurry polymerization, gas phase polymerization and high pressure ion polymerization can be mentioned. Bulk polymerization refers to: a method of polymerizing an olefin in a liquid state as a medium at a polymerization temperature. Solution polymerization or slurry polymerization means: a method of polymerizing in an inert hydrocarbon solvent such as propane, butane, isobutane, pentane, hexane, heptane, octane, etc. Gas phase polymerization refers to: a method of polymerizing a monomer in a gaseous state in a medium containing the monomer in a gaseous state. These polymerization methods may be either a batch type or a continuous type, or may be either a single-stage type in which the polymerization is carried out in a single polymerization vessel or a multistage type in which the polymerization is carried out in a polymerization apparatus in which a plurality of polymerization reaction vessels are connected in series. Polymerization conditions such as polymerization temperature, polymerization pressure, monomer concentration, catalyst input amount, and polymerization time in the polymerization step may be appropriately determined.

Examples of the catalyst used for producing the component (A-2) include a Ziegler Natta catalyst and a single-site catalyst.

Examples of the method for producing the component (A-2) include the production methods described in Japanese patent application laid-open Nos. Hei 4-11604, 2006-233207, 2007-269997, 2009-161779 and 2009-256661.

Examples of The component (a-2) include スミカセン (registered trademark) EP, スミカセン (registered trademark) E, エクセレン (registered trademark) GMH, エクセレン (registered trademark) FX (both manufactured by sumitomo Chemical corporation), エボリュー (registered trademark), タフマー (registered trademark) (manufactured by プライムポリマー corporation), ハーモレックス (registered trademark), カーネル (registered trademark) (manufactured by japan polyethylene corporation), Enable (registered trademark), exceeded (registered trademark) (both manufactured by ExxonMobil Chemical corporation), ELITE (registered trademark), and afifinity (registered trademark) (manufactured by The dow Chemical Company).

< ingredient (B) >

Examples of the unsaturated ester-based monomer unit include an α, β -unsaturated carboxylic acid alkyl ester-based monomer unit and a carboxylic acid vinyl ester-based monomer unit.

The component (B) does not substantially contain a monomer unit based on an alicyclic saturated hydrocarbon. The content of the alicyclic saturated hydrocarbon-based monomer unit in the component (B) is preferably 5% by weight or less, more preferably 3% by weight or less.

The resin composition may contain only 1 component (B), or may contain 2 or more components.

Examples of the α, β -unsaturated carboxylic acid alkyl ester include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate.

Examples of vinyl carboxylates include vinyl acetate, vinyl propionate, vinyl butyrate and vinyl benzoate.

The unsaturated ester-based monomer unit is preferably a methyl acrylate-based monomer unit, an ethyl acrylate-based monomer unit, a butyl acrylate-based monomer unit, a methyl methacrylate-based monomer unit, and a vinyl acetate-based monomer unit.

Examples of the component (B) include an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-butyl acrylate copolymer, an ethylene-methyl methacrylate copolymer, an ethylene-ethyl methacrylate copolymer, an ethylene-vinyl acetate copolymer, an ethylene-vinyl propionate copolymer, an ethylene-vinyl butyrate copolymer, and an ethylene-vinyl benzoate copolymer, and preferably an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-butyl acrylate copolymer, an ethylene-methyl methacrylate copolymer, and an ethylene-vinyl acetate copolymer, and more preferably an ethylene-vinyl acetate copolymer.

A part of the monomer units in the component (B) may be modified by hydrolysis or the like. As an example of the modified ethylene-unsaturated ester copolymer, a saponified ethylene-vinyl acetate copolymer can be cited.

The MFR of the component (B) is preferably 0.01 ~ 50g/10 min, more preferably 0.1 ~ 20 g/min, still more preferably 1.5 ~ 10g/10 min.

The upper limit of the content of the unsaturated ester-based monomer unit contained in the component (B) is preferably 50% by weight, more preferably 40% by weight, and still more preferably 30% by weight, and the lower limit of the content (% by weight) of the unsaturated ester-based monomer unit contained in the component (B) is preferably 5% by weight, more preferably 10% by weight, and still more preferably 15% by weight, with respect to 100% by weight of the total weight of the ethylene-based monomer unit and the unsaturated ester-based monomer unit contained in the component (B). The content (% by weight) of the unsaturated ester-based monomer unit contained in the component (B) is preferably 5% by weight or more and less than 50% by weight, more preferably 10% by weight or more and 40% by weight or less, and further preferably 15% by weight or more and 30% by weight or less.

The method for producing the component (B) includes a high-pressure radical polymerization method in which ethylene and an unsaturated ester are copolymerized in the presence of a radical initiator at 50 ~ 400MPa and 100 ~ 300 ℃ in the presence or absence of an appropriate solvent or chain transfer agent, and the average molecular weight of the component (B) and the content of the unsaturated ester in the component (B) can be controlled by adjusting the polymerization conditions of the high-pressure radical polymerization.

Examples of the component (B) include エバテート (registered trademark), スミテート (registered trademark), アクリフト (registered trademark) (all manufactured by sumitomo chemical corporation), エバフレックス (registered trademark), ニュクレル (registered trademark), エルバロイ (registered trademark) AC (manufactured by sanjing & seedy デュポンポリケミカル corporation), ノバテック (registered trademark) EVA (manufactured by japanese polyethylene corporation), ウルトラセン (registered trademark), メルセン (registered trademark) H (manufactured by eastern cao corporation), UBE polyethylene (EVA) (mada yushu pill polyethylene corporation), Elvax (registered trademark), AND APPEEL (registered trademark) (manufactured by DUPONT DE NEMOURS AND COMPANY).

< ingredient (C) >

Component (C) may contain a monomer unit based on a monomer other than the alicyclic saturated hydrocarbon. Examples of the monomer other than the alicyclic saturated hydrocarbon include aromatic hydrocarbons and alicyclic unsaturated hydrocarbons. The number of the monomer units based on the alicyclic saturated hydrocarbon is preferably 70% or more, more preferably good% or more, with respect to 100% of the total number of the monomer units contained in the component (C).

The component (C) may be a resin obtained by cyclizing and dimerizing a petroleum fraction containing a hydrocarbon having 4 carbon atoms 4 ~ 10 and polymerizing the same, a hydrogenated product of a resin obtained by polymerizing a cyclic diene compound such as cyclopentadiene, an aromatic hydrocarbon resin, or a resin obtained by intranuclear hydrogenation of an aliphatic hydrocarbon/aromatic hydrocarbon copolymer resin, and the component (C) may be obtained by partially or completely hydrogenating a polymer of a hydrocarbon having 4 carbon atoms 4 ~ 10 in a cracked oil fraction by-product in the production of ethylene, propylene, or the like.

The weight average molecular weight of the component (C) is preferably 800 ~ 1900, more preferably 1000 ~ 1800.

The Vickers softening point of the component (C) is preferably 110 ℃ or higher, more preferably 130 ℃ or higher. The Vickers softening point of the component (C) is determined by the ring and ball method.

The content of the component (C) is 2 to 10% by weight relative to 100% by weight of the total amount of the components (A), (B) and (C). The content of the component (C) in the entire polymer in the resin composition is preferably 2.5% by weight or more and 9% by weight or less, and more preferably 3% by weight or more and 8% by weight or less.

Based on 100% by weight of the total amount of the component (A), the component (B) and the component (C),

the content of the unsaturated ester-based monomer unit in the entire polymer in the resin composition is 3wt% or more and 10 wt% or less, preferably 4 wt% or more, more preferably 8 wt% or less, and may be 4 wt% or more and 8 wt% or less. The content of the unsaturated ester-based monomer unit contained in the entire polymer in the resin composition can be controlled by adjusting the contents of the components (a), (B), and (C) or the content of the unsaturated ester-based monomer unit contained in the component (B).

The content of the unsaturated ester-based monomer unit in the entire polymer in the resin composition is 3wt% or more and 10 wt% or less, and the content of the component (C) is 2 wt% or more and 10 wt% or less with respect to 100 wt% of the total amount of the components (a), (B), and (C), whereby D730/D720 can be 0.680 or more and 0.900 or less, and T1/T0 can be 1.80 or more and 2.20 or less.

The content of the component (a) is preferably 50% by weight or more and 90% by weight or less, and more preferably 65% by weight or more and 85% by weight or less, based on 100% by weight of the total amount of the components (a), (B), and (C) contained in the resin composition.

The content of the component (B) is preferably 10% by weight or more and 50% by weight or less, and more preferably 15% by weight or more and 30% by weight or less, based on 100% by weight of the total amount of the components (a), (B), and (C) contained in the resin composition.

The total amount of the components (A), (B) and (C) is preferably 90% by weight or more, more preferably good or good, based on 100% by weight of the total amount of the resin composition.

The total amount of the components (a), (B), and (C) is preferably 95% by weight or more, more preferably 98% by weight or more, and still more preferably 100% by weight, based on 100% by weight of the total amount of all polymers in the resin composition.

Additives may be added to the resin composition as needed. Examples of the additives include antiblocking agents, antioxidants, lubricants, antistatic agents and processability-improving materials.

The antiblocking agent is preferably added in an amount of 0.1 ~ 5 parts by weight, more preferably 0.3 ~ 3 parts by weight, based on 100 parts by weight of the total amount of the components (A) and (B).

The anti-blocking agent is preferably fine particles (hereinafter, sometimes referred to as component (D)) having a refractive index of 1.48 to 1.55, a particle diameter (D50) of 6 to 15 μm in terms of a cumulative percentage of volume-based particle size distribution of 50%, and a weight change rate E of less than 5% as determined by the following formula (1).

E＝100(G-F)/F (1)

(in the formula (1), E represents a weight change rate (% by weight). F represents a weight (G) of the fine particles after the fine particles are dried at a temperature of 110 ℃ under reduced pressure until a weight reduction rate per 1 hour becomes 0.1% by weight or less.) G represents a weight (G) of the fine particles after the fine particles subjected to the measurement of F are held at a relative humidity of 75% and a temperature of 40 ℃ for 24 hours under normal pressure).

The resin composition may contain only 1 component (D), or may contain 2 or more components.

The refractive index of the component (D) is more preferably 1.49 or more and 1.52 or less. The refractive index was measured by the critical angle method.

The particle diameter (D50) of the component (D) is more preferably 6 to 9 μm, and still more preferably 6 to 8 μm in terms of a cumulative percentage of volume-based particle size distribution of 50%. The volume-based particle size distribution of the component (D) is measured by a laser diffraction/scattering method.

From the viewpoint of improving the transparency of the obtained film, the particle diameter (D90) of the component (D) is preferably 9 μm or more in terms of the cumulative percentage of the particle size distribution on a volume basis of 90%.

From the viewpoint of effectively reducing blocking between the obtained sealing layers, D90 of the component (D) is preferably 18 μm or less, more preferably 16 μm or less, further preferably 15 μm or less, and particularly preferably 14 μm or less.

The component (D) is preferably at least one kind of fine particles selected from the group consisting of methyl methacrylate polymer fine particles, sodium calcium aluminosilicate fine particles, sodium aluminosilicate fine particles, calcined kaolin fine particles, calcined diatomaceous earth fine particles and calcined silica fine particles, more preferably at least one kind of fine particles selected from the group consisting of methyl methacrylate polymer fine particles, sodium calcium aluminosilicate fine particles and sodium aluminosilicate fine particles, and still more preferably sodium calcium aluminosilicate fine particles from the viewpoint of improving the film transparency.

The content of the component (D) in the resin composition is preferably 30,000ppm or less, more preferably 27,000ppm or less, further preferably 20,000ppm or less, and particularly preferably 17,000ppm or less, from the viewpoint of transparency and appearance of a film comprising the resin composition. From the viewpoint of preventing blocking of the seal layers to each other, it is preferably 3,000ppm or more, more preferably 5,000ppm or more, further preferably 10,000ppm or more, particularly preferably 15,000ppm or more, preferably 3,000ppm or more and 30,000ppm or less, more preferably 5,000ppm or more and 27,000ppm or less, further preferably 10,000ppm or more and 20,000ppm or less, particularly preferably 15,000ppm or more and 17,000ppm or less.

Examples of the antioxidant include phenol stabilizers such as 2, 6-di-t-butyl-p-cresol (BHT), tetrakis [ methylene-3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate ] methane (チバ, product name: IRGANOX1010, manufactured by Anthrix スペシャリティーケミカルズ), n-octadecyl-3- (4 '-hydroxy-3, 5' -di-t-butylphenyl) propionate (チバ, product name: IRGANOX1076), phosphite stabilizers such as bis (2, 4-di-t-butylphenyl) pentaerythritol diphosphite and tris (2, 4-di-t-butylphenyl) phosphite, and phenol-phosphite bifunctional stabilizers such as 6- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propoxy ] -2,4,8, 10-tetra-t-butylbenzo [ d, f ] [1,3,2] dioxaphosphepin (manufactured by Sumito chemical Co., product name: dioxaphosphepin) (d, f ] [1,3,2] dibenzo-p-ene) (manufactured by Sumitomo chemical Co., product name: P), preferably 0.001 parts by weight, 0.001 parts, 0.591 parts, and more preferably 0 parts by weight relative to the total weight of the component (A) and the component (B).

The amount of the lubricant added is preferably 0.01 ~ 1 parts by weight, more preferably 0.03 ~ 0.5.5 parts by weight, based on 100 parts by weight of the total amount of the component (A) and the component (B).

The antistatic agent is preferably added in an amount of 0.01 ~ parts by weight, more preferably 0.1 ~.5 parts by weight, based on 100 parts by weight of the total amount of the component (A) and the component (B) in the composition.

The workability improving agent may be a fatty acid metal salt such as calcium stearate, and the amount of the workability improving agent added is preferably 0.01 ~ 1 parts by weight, more preferably 0.1 ~ 0.5.5 parts by weight, based on 100 parts by weight of the total amount of the component (a) and the component (B).

The additive may be added after the component (a) and the component (B) and the component (C) contained in the resin composition are blended in advance, may be added to either or both of the component (a) and the component (B), or may be used as a master batch blended with either of the component (a) and the component (B).

The resin composition can be produced by a known blending method. Known blending methods include a method of dry blending the respective polymers and a method of melt blending. As a method of dry blending, a method using various mixers such as a Henschel mixer and a tumbler mixer can be exemplified. Examples of the method of melt blending include a method using various mixers such as a single-screw extruder, a twin-screw extruder, a banbury mixer, and a hot roll.

The film comprises a base material layer and a sealing layer, wherein one surface of the film is the base material layer, and the other surface of the film is the sealing layer. The film may have layers other than the substrate layer and the sealant layer.

The film can be produced by a lamination method in which a single-layer film composed only of a sealant layer or a multilayer film having a sealant layer and layers other than the base material layer and the sealant layer is laminated on a base material. Examples of the lamination method include a dry lamination method, a wet lamination method, and a sandwich lamination method.

A monolayer film composed only of the sealant layer and a multilayer film having the sealant layer and layers other than the base material layer and the sealant layer can be manufactured by inflation film forming.

Examples of the layer other than the base layer and the sealant layer include a layer containing a vinyl polymer. Examples of the ethylene polymer include high-pressure low-density polyethylene and ethylene- α -olefin copolymer.

The multilayer film having a sealant layer and layers other than the base material layer and the sealant layer may be a multilayer film (α) having a sealant layer and a layer containing an ethylene-based polymer, and at least one surface of the multilayer film being the sealant layer. The multilayer film (α) can be produced by co-extruding the resin composition for forming the sealant layer and the ethylene polymer and blow-molding the resulting film.

The thickness of the sealing layer of the film is 5 μm or more and 100 μm or less, preferably 10 μm or more and 80 μm or less, and more preferably 15 μm or more and 50 μm or less. The thickness of the sealing layer of the film was measured by performing thin cutting along the thickness direction of the film using a cryomicrotome, and observing a cross section of the resulting test piece using an optical microscope.

Examples of the substrate include polyamide resins such as cellophane, paper, cardboard, woven fabric, aluminum foil, nylon 6, and nylon 66, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and a layer containing stretched polypropylene.

The film may be used as a lid for various containers. Examples of the material of the container include propylene homopolymer, propylene random copolymer, high-density polyethylene, ethylene- α -olefin copolymer, high-pressure low-density polyethylene, and polystyrene. The film can be used as a lid for a packaging container for various foods such as jelly, pudding, yogurt, tofu, instant noodles, and noodles, pharmaceuticals, cosmetics, and industrial products.

Examples of the propylene homopolymer used as a container material include a homopolymer grade of sumitomo ノーブレン (registered trademark) (manufactured by sumitomo chemical corporation) and a homopolymer grade of プライムポリプロ (manufactured by プライムポリマー corporation). Examples of the random propylene copolymer used as a container material include a random grade of sumitomo ノーブレン (registered trademark) (manufactured by sumitomo chemical corporation) and a random grade of プライムポリプロ (manufactured by プライムポリマー corporation). Examples of the high-density polyethylene used as a container material include ノバテック (registered trademark) HD (manufactured by japanese polyethylene corporation), ハイゼックス (registered trademark), and エボリュー (registered trademark) H (all manufactured by プライムポリマー corporation). The polystyrene used as the container material includes PS プレート (HIPS) manufactured by hydroprocessmg industries, ltd.

The sealed container can be produced by superposing the lid on the flange portion of the container body so that the sealing layer of the lid including the film is in contact with the flange portion of the container body, and heat-sealing the lid and the flange portion by applying heat and pressure.

From the viewpoint of compatibility between the sealing property and the easy-opening property, the heat seal strength of the lid including the film is preferably 10 ~ 25N/mm.

Examples

(1) Raw material resin and additive

Component (A)

PE 1: metallocene catalyst Linear Low Density polyethylene スミカセン EP GT140 (ethylene-1-butene-1-hexene copolymer, manufactured by Sumitomo chemical Co., Ltd., MFR 0.9g/10 min, density 918kg/m³、Mw/Mn＝8.6、Ea＝69.3kJ/mol)

PE 2: metallocene catalyst Linear Low Density polyethylene スミカセン E FV201 (ethylene/1-hexene copolymer, manufactured by Sumitomo chemical Co., Ltd., MFR 2.3g/10 min, density 916kg/m³、Mw/Mn＝5.8、Ea＝35.8kJ/mol)。

Ingredient (B)

OE 1: スミテート KA-30 (ethylene-vinyl acetate copolymer manufactured by Sumitomo chemical Co., Ltd., having a vinyl acetate-based monomer unit content of 28 wt% and an MFR of 7.0g/10 min)

OE 2: アクリフト WK307 (ethylene-methyl methacrylate copolymer manufactured by Sumitomo chemical Co., Ltd., having a methyl methacrylate-based monomer unit content of 25 wt% and an MFR of 7.0g/10 min).

Ingredient (C)

TA 1: アルコン P-140 (ring and ball softening point 140 ℃ C. manufactured by Mitsubishi chemical industries, Ltd.)

TA 2: クレイトン G1657 (SEBS styrene-ethylene/butylene-styrene block copolymer, manufactured by クレイトンポリマージャパン Co., Ltd., MFR (230 ℃ C.) 8G/10 min, styrene monomer content 13 wt%).

Others

AO: antioxidant スミライザー GP (manufactured by Sumitomo chemical Co., Ltd.)

And SA: lubricant erucamide

AB: the anti-blocking agent Minbloc SC6 (silica, refractive index 1.51, manufactured by Sibelco).

(2) Heat seal strength

The sealing layer of the prepared laminate film was superposed so as to be in contact with each adherend described below, and heat-sealed by a heat sealer (manufactured by テスター industries, Ltd.) under the following sealing conditions to obtain a sample, the obtained sample was adjusted at 23 ℃ for 24 hours or longer, and then a test piece having a sealing portion with a sealing width of 10mm and a sealing length of 15mm was cut out along the direction perpendicular to the sealing width direction, and then the sealing portion of the obtained test piece was peeled off at a speed of 300 mm/min by a tensile tester at 180 ° to measure the heat-sealing strength per 15mm width, and the maximum value of the obtained heat-sealing strength was used, and if the heat-sealing strength was 10 ~ 25N/15mm, the film was provided with sealability and easy-sealability.

Conditions of heat sealing

Sealing temperature: 160 deg.C

Sealing time: 1 second

Width of a sealing strip: 10mm

Sealing pressure: 450 kPa.

Adherend and method for producing the same

Adherend 1: polypropylene sheet material (PP)

(ノーブレン (registered trademark) sheet of H501, 0.44mm thick).

Adherend 2: impact-resistant polystyrene sheet (HIPS)

(manufactured by Nippon Plastic industries, Ltd., MFR of 3.4g/10 min, Vickers softening point of 96 ℃, PS sheet thickness of 0.5mm, Charpy impact strength of 11kJ/m²)。

(3) Haze degree

The haze (unit:%) of an inflation film (thickness: 60 μm) molded by the method described later was measured in accordance with ASTM 1003. The smaller the haze, the more excellent the transparency.

(4) Internal haze

A blown film (thickness: 60 μm) formed by the method described later was immersed in a transparent dish containing dimethyl phthalate, and the internal haze (unit:%) of the film in the immersed state was measured. The smaller the internal haze, the more excellent the transparency.

(5) Adhered up and down (upper and lower BL, unit: N/m)²)

A blown film (thickness: 60 μm) formed by the method described later was cut into 10cm X10 cm, and the film was superimposed so that the inner sides of the tubes in the blown film formation were closely adhered to each other, and the film was heated in an oven adjusted to 40 ℃ at 400g/cm²Is left standing for 7 days under the load of (1). After standing, the load amount required for peeling in the vertical direction at a peeling load speed of 20 g/min was measured using a mackenzie blocking tester (manufactured by shimadzu corporation). The smaller the value, the more excellent the blocking resistance.

(6) Melt flow Rate (MFR, Unit: g/10 min)

MFR was measured by the method A defined in JIS K7210-1995 at a temperature of 190 ℃ and a load of 21.18N.

(7) Charpy impact strength

Charpy impact strength was measured in accordance with JIS K7111.

(8) Content of vinyl acetate-based monomer units

The content of vinyl acetate-based monomer units was measured in accordance with JIS K7192.

(9) Production of the masterbatch

The component (a) and the additive were melt-kneaded at 160 ℃ in a banbury mixer at the ratio shown in table 1, and then pelletized by a pelletizer to prepare an additive masterbatch.

[ Table 1]

。

(10) Surface crystallinity index

Infrared spectroscopic measurement by Attenuated Total Reflection (ATR) method was performed according to the apparatus and measurement procedure described later.

Seed planting device: fourier transform infrared spectrophotometer FT/IR-480, multiple reflectance measurement device ATR-500M (manufactured by Japan Spectroscopy Co., Ltd.), prism KRS-5/45 ° (manufactured by Sanyo science Co., Ltd.)

Seed measurement mode: abs

Seed and seed resolution ratio: 4cm^-1、

Seed and accumulation frequency: 32 times of,

Seed production and ATR-IR measurement: the sealing layer on the film surface was brought into contact with the upper and lower surfaces of the KRS-5 prism to obtain an infrared absorption spectrum.

The absorbance Abs of the obtained infrared absorption spectrum was taken as the vertical axis, and 760 ~ 674cm was set^-1As a baseline. 725cm in the obtained infrared absorption spectrum^-1Above and 735cm^-1In the following range, the peak having the largest height from the baseline is D730. At 715cm of the obtained infrared absorption spectrum^-1Above and less than 725cm^-1D730 is defined as the peak having the largest height from the baseline. The surface crystallinity index was determined by the following formula.

Seeded surface crystallization index (D730/D720).

(11) Phase difference microscope observation

In a state where the sealing layer on the film surface was brought into contact with the adherend 2, the film was heat-sealed to the adherend 2 under conditions of a temperature of 160 ℃, a time of 1 second, a sealing strip width of 10mm, and a pressure of 450kPaAnd obtaining a sample. The obtained sample was cut in the thickness direction of the film in parallel with the heat-seal width using a cryomicrotome (manufactured by LEICA), to obtain a test piece having a thickness of 6 μm. The cut surface of the obtained test piece was set as an observation surface. Dimethyl phthalate was attached to a glass slide, and the test piece obtained thereon was placed with its cross section facing upward. The observation surface was measured by a phase-contrast microscope of NIKON MICROPHOT FXA (manufactured by Nikon corporation), and an image was obtained. Using the obtained image, T was measured₀And T₁。

The thickness of the sealant layer on the film surface of the non-heat-sealed portion was measured.

T₁The measurement was carried out by the following method.

(1) The end point of the bonding part between the sealing layer and the adherend 2 is denoted by P₁。

(2) The tangent line L and P of the boundary line between the sealing layer and the layer other than the adherend 2 were obtained₁The shortest distance of (c).

T₀The measurement was performed by performing thin cutting along the thickness direction of the film using a cryomicrotome and observing the cross section of the resulting test piece using an optical microscope.

(12) Vickers softening point

The Vickers softening point was measured by the method specified in JIS K7206 under the condition of a load of 50N.

(example 1)

[ Co-extrusion blown film formation ]

The inflation film is produced by a coextrusion inflation molding method so that an outer layer, an intermediate layer, and an inner layer are laminated in this order. As the resin composition for the outer layer and the resin composition for the intermediate layer, EFV202 (ethylene-1-hexene copolymer, manufactured by Sumitomo chemical Co., Ltd.) containing ethylene polymer スミカセン (registered trademark) having MFR of 2.0g/10 min and density of 925kg/m was used³)80 wt.% ethylene Polymer スミカセン (registered trade Mark) F200 (high pressure Low Density polyethylene, manufactured by Sumitomo chemical Co., Ltd., MFR 2.0g/10 minThe density of the resin composition was 924kg/m³) 20% by weight of the resin composition. As the resin composition for inner layer, resin compositions containing PE1, OE1, TA1 and MB1 in the compounding amounts shown in table 2 were used.

The co-extrusion inflation molding was carried out by using a three-layer inflation film processing machine manufactured by プラコー under conditions of a mold temperature of 170 ℃, a total extrusion amount of 30 kg/hour, a blow ratio of 2.0, and a take-up speed of 9.5 m/min, to produce a co-extrusion inflation film having a thickness composition ratio of 20 μm/20 μm/20 μm in the order of outer layer/intermediate layer/inner layer, and a total thickness of 60 μm. The outer layer surface of the resulting blown film tube was subjected to corona discharge treatment in such a manner that the wetting tension reached 45 dyn/cm. The physical properties of the obtained blown film are shown in table 3. The inner layer of the blown film contained a vinyl acetate-based monomer unit in an amount of 5% by weight.

[ Forming of laminated film ]

A polyester film (trade name "E5102", manufactured by Toyo Seiki Seisaku) having a thickness of 12 μm and a width of 500mm was coated with a liquid obtained by mixing "タケラック A-310" and "タケネート A-3" (both manufactured by Mitsui Wutian chemical Co., Ltd.) as an aliphatic ester coating agent at the following mixing ratio using a coater manufactured by Kangjing Seiki Seisaku. The corona-treated surface of the film obtained in the above example was bonded to the obtained polyester film, and then heated in an oven at 40 ℃ for 48 hours to obtain a laminated film.

タケラック/タケネート/EtOAc 12/1/32 (weight ratio)

The heat seal strength was measured using the laminated film. The results are shown in Table 3. Table 4 shows D730/D720 and T1/T0 of the laminate film.

(example 2)

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1, TA1 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. The inner layer of the blown film contained a content of vinyl acetate-based monomer units of 9.5 wt%.

(example 3)

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1, TA1 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. Table 4 shows D730/D720 and T1/T0 of the laminate film. The inner layer of the blown film contained a content of vinyl acetate-based monomer units of 9 wt%.

(example 4)

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1, TA1 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. Table 4 shows D730/D720 and T1/T0 of the laminate film. The inner layer of the blown film contained a vinyl acetate-based monomer unit in an amount of 3.4 wt%.

(example 5)

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1, TA1 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. Table 4 shows D730/D720 and T1/T0 of the laminate film. The inner layer of the blown film contained a vinyl acetate-based monomer unit in an amount of 8.4 wt%.

(example 6)

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE2, OE1, TA1 and MB2 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. The inner layer of the blown film contained a content of vinyl acetate-based monomer units of 9.5 wt%.

(example 7)

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE2, TA1 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. The inner layer of the blown film contained a content of a methyl methacrylate-based monomer unit of 3.8% by weight.

Comparative example 1

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, TA1 and MB1 were set to the blending amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. Table 4 shows D730/D720 and T1/T0 of the laminate film. The inner layer of the blown film contained the unsaturated ester-based monomer unit in an amount of 0% by weight.

Comparative example 2

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1 and MB1 were set to the blending amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. The inner layer of the blown film contained a vinyl acetate-based monomer unit in an amount of 10% by weight.

Comparative example 3

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1, TA1 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. The inner layer of the blown film contained a vinyl acetate-based monomer unit in an amount of 13% by weight.

Comparative example 4

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1, TA1 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. Table 4 shows D730/D720 and T1/T0 of the laminate film. The inner layer of the blown film contained a content of vinyl acetate-based monomer units of 12 wt%.

Comparative example 5

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1, TA2 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. The inner layer of the blown film contained a vinyl acetate-based monomer unit in an amount of 11 wt%.

Comparative example 6

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1, TA1 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. Table 4 shows D730/D720 and T1/T0 of the laminate film. The inner layer of the blown film contained a vinyl acetate-based monomer unit in an amount of 2.8% by weight.

Comparative example 7

Comparative example 8

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1 and MB1 were set to the blending amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. The inner layer of the blown film contained a vinyl acetate-based monomer unit in an amount of 3.4 wt%.

Comparative example 9

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1, TA1 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. Table 4 shows D730/D720 and T1/T0 of the laminate film. The inner layer of the blown film contained a content of vinyl acetate-based monomer units of 9.8 wt%.

Comparative example 10

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1, TA1 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. The crystal index of the surface of the sealing layer of the laminate film is shown in table 4. The inner layer of the blown film contained a vinyl acetate-based monomer unit in an amount of 11.8 wt%.

Comparative example 11

Blown films and multilayer films were obtained in the same manner as in example 1, except that PE1, OE1, TA2 and MB1 were used in the amounts shown in table 2. The physical properties of the blown film and the laminated film are shown in table 3. The crystal index of the surface of the sealing layer of the laminate film is shown in table 4. The inner layer of the blown film contained a vinyl acetate-based monomer unit in an amount of 4.8% by weight.

[ Table 2]

(the unit of the amount of each component in Table 2 is wt%).

[ Table 3]

。

[ Table 4]

。

This patent application is based on the priority claim of japanese patent application No. 2017-094501 (2017, 5/11/d), which is incorporated herein by reference in its entirety.

Claims

1. A film which comprises a base layer and a sealant layer and has a thickness of 20 [ mu ] m or more and 150 [ mu ] m or less,

one surface layer of the film is a base material layer, the other surface layer is a sealing layer,

the sealing layer contains a resin composition and has a thickness of 5 [ mu ] m or more and 100 [ mu ] m or less,

the surface of the sealing layer on the surface of the film has a crystallinity index D730/D720 of 0.680 or more and 0.900 or less as measured by a multiple reflection ATR-IR method,

when the film is heat-sealed to the adherend (X) under the conditions of a temperature of 160 ℃, a time of 1 second, a sealing strip width of 10mm, and a pressure of 450kPa in a state where the sealing layer on the film surface is brought into contact with the adherend (X), the ratio of the thickness of a portion formed by the resin composition of the sealing layer dissolving out from the heat-sealed portion to the non-heat-sealed portion and curing to the thickness of the sealing layer of the non-heat-sealed portion is 1.80 to 2.20,

2. The film according to claim 1, wherein D730/D720 is 0.680 or more and 0.750 or less.

3. The film according to claim 1 or 2, wherein, when heat-sealed to an adherend (X) under conditions of a temperature of 160 ℃, a time of 1 second, a seal strip width of 10mm, and a pressure of 450kPa, a ratio of a thickness of a portion formed by elution and solidification of the resin composition of the seal layer from the heat-sealed portion to the non-heat-sealed portion to a thickness of the seal layer of the non-heat-sealed portion is 1.85 or more and 2.20 or less.

4. A lid comprising the film of any one of claims 1 ~ 3.