JP6973688B2 - Laminated film and lid material - Google Patents

Description

The present invention relates to a laminated film having good adhesiveness to an adherend such as a heat-sealed portion of a packaging container and capable of realizing easy-opening property that can be preferably peeled off.

Conventionally, materials such as polyethylene, polypropylene, and polyethylene terephthalate have been widely used for various plastic packaging materials such as packaging bags and packaging containers. In recent years, these plastic packaging materials use plant-derived raw materials because they use fossil resources as raw materials and do not decompose for a long period of time when discarded in the environment, which has a large impact on the environment. The use of carbon-neutral resins (non-fossil raw materials) that have a low environmental load, such as bio-resins that have been used, biodegradable resins that decompose by hydrolysis or biodegradation in soil or water, is being studied.

As an environment-friendly packaging material, for example, a laminated film using a heat-sealed resin layer containing a lactic acid polymer as a main component is disclosed as a film applicable to a container of a lactic acid polymer. (See Patent Document 1). The laminated film has suitable heat-sealing properties and easy-opening properties for containers and the like of lactic acid-based polymers, but is suitable for various conventionally used packaging materials as described above. It was difficult to achieve both sex and easy opening.

Japanese Unexamined Patent Publication No. 2007-290311

The problem to be solved by the present invention is to provide a laminated film which has heat-sealing property and easy-opening property suitable for various materials including environmental load reducing materials and can be suitably used for packaging applications. There is something in it.

Further, the problem to be solved by the present invention is to provide a laminated film which can realize suitable heat-sealing property and easy-opening property in a wide temperature range for various materials and also has suitable impact resistance. To do.

The present invention has a heat-sealed layer (A) and a base material layer (B), one surface layer of which is the surface of the heat-sealed layer (A) and the other surface layer of which is the surface of the base material layer (B). The heat-sealed layer (A) solves the above problem with a laminated film containing a polylactic acid-based resin (a1) and a polybutylene succinate-based resin (a2).

Since the laminated film of the present invention can realize suitable heat-sealing properties and easy-opening properties not only for polylactic acid-based resins but also for materials such as polyethylene, polypropylene, and polyethylene terephthalate, it can be used as a packaging material for various containers and bags. It is not necessary to select a film to be applied to each material, which is useful for promoting the spread of materials that reduce environmental load.

The laminated film of the present invention can be suitably used as various packaging materials because it can realize suitable impact resistance while having suitable heat sealing property and easy opening property in a wide temperature range. Further, since it contains a biodegradable resin as a material constituting the heat seal layer and a plant-derived resin or a biodegradable resin can be used as a material for other layers, it is excellent in environmental friendliness.

The laminated film of the present invention has a heat seal layer (A) and a base material layer (B), one surface layer is the surface of the heat seal layer (A), and the other surface layer is the surface of the base material layer (B). In a laminated film, the heat seal layer (A) contains a polylactic acid-based resin (a1) and a polybutylene succinate-based resin (a2).

[Heat seal layer (A)]
The heat seal layer (A) used in the present invention contains a polylactic acid-based resin (a1) and a polybutylene succinate-based resin (a2) as resin components. By containing the resin as the heat-sealing layer, it is possible to realize suitable heat-sealing properties and easy-opening properties for various adherends.

Examples of the polylactic acid resin (a1) used for the heat seal layer (A) include polylactic acid (poly (D-lactic acid), poly (L-lactic acid)), and a copolymer of D-lactic acid and L-lactic acid. , A copolymer of D-lactic acid and other hydroxycarboxylic acids, a copolymer of L-lactic acid and other hydroxycarboxylic acids, and a polyester component obtained by ester-reacting dicarboxylic acid and diol with the lactic acid component. Examples thereof include a polymer obtained by polymerizing. Of these, polylactic acid is preferable from the viewpoint of film formation stability and availability, and polylactic acid whose main structural unit is L-lactic acid is more preferable. These polymers may be used alone or in combination.

Examples of the hydroxycarboxylic acid, diol, and dicarboxylic acid include hydroxycaproic acids such as glycolic acid, hydroxybutyric acid, and hydroxycaproic acid, and hydroxycarboxylic acids such as cyclic lactones such as caprolactone, butyrolactone, lactide, and glycolide; Aliphatic diols such as propylene glycol, 1,4-butanediol and 1,4-cyclohexanedimethanol; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid; succinic acid, adipic acid, sveric acid and sebacic acid Examples thereof include aliphatic dicarboxylic acids such as.

Since the polylactic acid-based resin (a1) tends to achieve good fluidity during extrusion molding, the melt flow rate (190 ° C., 21.18N) is preferably 0.5 to 20 g / 10 min, more preferably 2 It is 10 g / 10 min. Within the range of such a melt flow rate, extrusion molding is easy, and when coextrusion multi-layered, it becomes easy to obtain a laminated film having good fluidity with an adjacent layer and having a better appearance.

It is preferable that the density of the polylactic acid resin (a1) is 1.20~1.26g / cm ^3, more preferably 1.23~1.25g / cm ^3.

Examples of the polybutylene succinate resin (a2) include poly (butylene succinate) (PBS) and poly (butylene succinate / adipate) copolymer (PBSA). The poly (butylene succinate) is a polycondensate of 1,4-butanediol and succinic acid, and the poly (butylene succinate / adipic acid) copolymer is added to 1,4-butanediol and succinic acid. , A polycondensate to which adipic acid is added. Such poly (butylene succinate and poly (butylene succinate / adipate) copolymers) can be made high molecular weight with lactic acid or a polyfunctional isocyanate compound in order to increase the molecular weight, and can be adjusted to an appropriate molecular weight.

The melt flow rate (190 ° C., 21.18 N) of the polybutylene succinate resin (a2) is preferably about 0.5 to 30 g / 10 min, more preferably 2 to 24 g / 10 min from the viewpoint of film extrusion moldability. Is.

It is preferable that the density of the polybutylene succinate resin (a2) is 1.20~1.29g / cm ^3, more preferably 1.21~1.27g / cm ^3.

The content ratio of the polylactic acid-based resin (a1) and the polybutylene succinate-based resin (a2) in the heat-sealed layer (A) is the mass ratio represented by (a1) / (a2), which is 75 /. It is preferably 25 to 25/75, more preferably 60/40 to 30/70. Within this range, transparency is improved, the balance between rigidity and impact resistance is improved, and low-temperature drop impact resistance under freezing and low-temperature storage is increased. As a result, the laminating print processability is also improved. Furthermore, the slipperiness of the sealing surface is improved, and the blocking resistance at high temperatures is also improved.

The total content of the polylactic acid-based resin (a1) and the polybutylene succinate-based resin (a2) in the heat-sealed layer (A) is the total of both in the resin component contained in the heat-sealed layer (A). It is preferably 80% by mass or more, more preferably 90% by mass or more, and the resin component may be substantially composed of only these resins. By setting these contents, it becomes easy to obtain suitable heat-sealing property, easy-opening property, impact resistance, etc. for various materials.

The heat seal layer (A) may contain a resin other than the above as long as the effect of the present invention is not impaired. As the other resin, a polyolefin resin such as an ethylene resin or a propylene resin or a polyester resin can be preferably exemplified. Examples of the ethylene-based resin include polyethylene resins such as linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE), and ethylene-vinyl acetate copolymers. , Ethethylene-methylmethacrylate copolymer, ethylene-ethylacrylate copolymer, polyethylene-methacrylic acid copolymer and the like. Examples of the propylene-based resin include a propylene homopolymer, a propylene-ethylene copolymer, a propylene-butene-1 copolymer, a propylene-ethylene-butene-1 copolymer, a metallocene-catalyzed polypropylene, and the like.

Examples of the resin other than the polyolefin resin include an ethylene-methyl methacrylate copolymer (EMMA), an ethylene-ethyl acrylate copolymer (EEA), an ethylene-methyl acrylate (EMA) copolymer, and an ethylene-ethyl. Ethylene-based copolymers such as acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA); and further ethylene-acrylic An acid copolymer ionomer, an ethylene-methacrylic acid copolymer ionomer, and the like can be used.

The polyester-based resin contains an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid as a dicarboxylic acid component which is a constituent monomer of polyester, and is made of polyethylene terephthalate (PET) or polyethylene naphthalate. (PEN) and the like are known. Further, the diol component which is the other constituent monomer of these aromatic polyester-based resins is not particularly limited. Usually, aliphatic diols such as ethylene glycol and 1,4-butanediol are often used, but in order to reduce the crystallinity without lowering Tg, an aliphatic diol such as cyclohexanedimethanol was used. Aromatic aliphatic polyester resin (PETG) can also be used.

When a resin other than the polylactic acid-based resin (a1) and the polybutylene succinate-based resin (a2) is used, the content thereof is 20% by mass or less in the resin component contained in the heat seal layer. It is preferable to use it in an amount of 10% by mass or less.

When these other resins are used, it is preferably 20% by mass or less, and more preferably 10% by mass or less in the resin component contained in the heat seal layer (A).

Various additives may be blended in the heat seal layer (A) as long as the effects of the present invention are not impaired. Examples of the additive include antioxidants, weather-resistant stabilizers, antistatic agents, anti-fog agents, anti-blocking agents, lubricants, nucleating agents, pigments and the like.

[Base layer (B)]
The base material layer (B) used in the present invention is a layer forming a surface layer opposite to the heat seal layer (A) of the laminated film. The base material layer (B) preferably contains a polyolefin-based resin as a main resin component because it is easy to obtain suitable film-forming properties and impact resistance of the film. As the polyolefin-based resin, the ethylene-based resin and the propylene-based resin exemplified in the heat-sealed layer (A) can be preferably used. Further, as the ethylene-based resin or propylene-based resin, it is preferable to use a plant-derived resin such as biopolyethylene or biopolypropylene produced from a plant-derived raw material because it is beneficial for reducing the environmental load.

The content of the polyolefin-based resin in the base material layer (B) is preferably 80% by mass or more, and more preferably 90% by mass or more in the resin component contained in the base material layer (B). It is also preferable that the resin is substantially only a polyolefin resin. By setting the content, it becomes easy to obtain suitable film forming property, impact resistance and the like.

As the polyolefin resin used for the base material layer (B), the melt flow rate (190 ° C.) of the ethylene resin is preferably about 0.5 to 20 g / 10 min, more preferably 2 to 10 g / 10 min from the viewpoint of film extrusion moldability. It is 10 min.

The density of the polyethylene resin ^{is preferably 0.88 to 0.96 g / cm 3} , more preferably 0.89 to 0.95 g / cm ^3.

As the polyolefin resin used for the base material layer (B), the melt flow rate (210 ° C.) of the polypropylene resin is preferably about 0.5 to 20 g / 10 min, more preferably 2 to 10 g / 10 min from the viewpoint of film extrusion moldability. It is 10 min.

It is preferable that the density of the polypropylene resin is 0.89~0.91g / cm ^3, more preferably 0.89~0.90g / cm ^3.

The base material layer (B) may contain a resin other than the above, and as the other resin, those exemplified as the resin other than the polyolefin resin in the heat seal layer (A) are exemplified. Can be used.

When a resin other than the olefin resin is used in the base material layer (B), the content thereof should be 20% by mass or less of the resin component contained in the base material layer (B). It is preferable to use it in an amount of 10% by mass or less.

Various additives may be blended in the intermediate layer (B) as long as the effects of the present invention are not impaired. Examples of the additive include antioxidants, weather-resistant stabilizers, antistatic agents, anti-fog agents, anti-blocking agents, lubricants, nucleating agents, pigments and the like.

[Middle layer (C)]
In the laminated film of the present invention, an intermediate layer is provided between the heat seal layer (A) and the base material layer (B) for the purpose of improving the interlayer adhesion and the film characteristics such as impact resistance. It is also preferable to provide (C). As the resin used for the intermediate layer (C), an acid-modified olefin resin or an ethylene-α-olefin copolymer weight can be easily obtained because the interlayer adhesion between the heat seal layer (A) and the base material layer (B) can be easily obtained. Combined rubber can be preferably used.

The acid-modified olefin-based resin is a polymer obtained by graft-copolymerizing an unsaturated carboxylic acid such as maleic anhydride or a derivative thereof with an olefin-based polymer. The amount of acid denaturation is preferably 2% by mass or more because it is easy to obtain adhesiveness with other layers. As the olefin-based polymer used for the acid-modified olefin-based resin, a copolymer of ethylene and an α-olefin such as propylene, butene, hexene, and octene can be preferably used.

The ethylene-α-olefin copolymer rubber is a low-crystalline or amorphous copolymer rubber (epolymer), and is composed of 50 to 90% by mass of ethylene, which is a main component, and α-, which is a copolymer monomer. It is a random copolymer with an olefin. As the α-olefin, propylene, 1-butene, 1-hexene, 1-octene and the like having 3 to 10 carbon atoms can be used, and as a specific ethylene-α-olefin copolymer rubber, ethylene-propylene random can be used. Examples thereof include copolymer rubber (EPR), ethylene-butene random copolymer (EBR), ethylene-octene random copolymer and the like. Among them, ethylene-butene random copolymer rubber can be preferably used.

Preferably the density of the ethylene -α- olefin copolymer rubber is 0.88~0.93g / cm ^3, more preferably 0.88~0.91g / cm ^3.

The melt flow rate (190 ° C., 21.18N) of the ethylene-α-olefin copolymer rubber is preferably 0.5 to 20 g / 10 minutes, more preferably 2 to 15 g / 10 min. ..

The content of the acid-modified olefin resin or the ethylene-α-olefin copolymer rubber in the intermediate layer (C) is preferably 70% by mass or more in the resin component contained in the intermediate layer (C). More preferably, it is 80% by mass or more. Further, it is also preferable that the resin component contained in the intermediate layer (C) is substantially only an acid-modified olefin resin, an ethylene vinyl acetate copolymer resin, or an ethylene-α-olefin copolymer rubber. When the acid-modified olefin resin and the ethylene-α-olefin polymer rubber are used in combination, the total amount of both is preferably in the above range.

In the intermediate layer (C), it is also preferable to use a tackifier resin in combination in order to improve the interlayer adhesion with other layers. Examples of the tackifying resin include natural resin and synthetic resin having adhesiveness at room temperature, and examples thereof include rosin-based resins such as natural resin rosin, polymerized rosin, hydrogenated rosin, glycernestel rosin, and pentaerythritol; Terpene resins such as terpenes, aromatic terpenes, terpenphenols, hydrogenated terpenes; aliphatic petroleum resins, aromatic petroleum resins, hydrogen alicyclic petroleum resins; polybutadiene liquid at room temperature, polyisoprene liquid at room temperature, Examples thereof include polyisobutylene which is liquid at room temperature.

When the tackifier resin is used, the content of the tackifier resin is preferably 30% by mass or less, and more preferably 5 to 20% by mass in the resin component contained in the intermediate layer (C). preferable.

In addition to the above, an olefin resin as exemplified in the heat seal layer (A) and the base material layer (B), a resin other than the olefin resin, or the like may be appropriately used in combination in the intermediate layer (C). good. When these other resins other than the above are used, the content of the other resin components is preferably 20% by mass or less of the resin components contained in the intermediate layer (C), preferably 10% by mass or less. It is more preferable to use in.

Various additives may be blended in the intermediate layer (C) as long as the effects of the present invention are not impaired. Examples of the additive include antioxidants, weather-resistant stabilizers, antistatic agents, anti-fog agents, anti-blocking agents, lubricants, nucleating agents, pigments and the like.

[Laminated film]
The laminated film of the present invention is a laminated film having the above-mentioned heat-sealed layer (A) and base material layer (B), one surface layer is the surface of the heat-sealed layer (A), and the other surface layer is the base material. The surface of the layer (B). By adopting the laminated film of the present invention, it is possible to realize suitable sealing property and easy-opening property for packaging materials of various materials.

In the laminated film of the present invention, the base material layer (B) may be composed of a single layer or may be composed of two or more layers. In particular, in the present invention, since the ratio of the base material layer (B) to the total thickness is high, two or more layers are used to facilitate the thickness adjustment with the heat seal layer (A) when the coextrusion method is used. The configuration is also preferable because it is easy to obtain a multilayer film having excellent homogeneity. When the base material layer (B) has a multi-layer structure, each layer of the base material layer (B) may be a layer using the above-mentioned preferable resin or composition, and the resin constituting each layer of the base material layer (B) may be used. The composition may be the exact same mixture, or different mixtures having different formulations, MFRs, and densities of the respective resins may be used.

The thickness (total thickness) of the laminated film of the present invention is preferably 10 to 70 μm, particularly in the range of 20 to 60 μm, from the viewpoint of weight reduction of the packaging material and easy opening. Is more preferable.

The thickness of each layer is preferably in the range of 5 to 30% of the total thickness of the film, and more preferably in the range of 8 to 25%. When the intermediate layer (C) is provided, the thickness of the base material layer (B) is preferably 25 to 55%, more preferably 30 to 50% of the total thickness of the film. The thickness of the intermediate layer (C) is preferably 5 to 30%, more preferably 8 to 25% of the total thickness of the film. By setting the thickness of each layer within the corresponding range, the heat seal strength is stabilized and it becomes easy to obtain an appropriate ease of opening.

As a specific preferable thickness, the heat seal layer (A) is preferably 2 to 15 μm, more preferably 3 to 12 μm. The base material layer (B) is preferably 15 to 55 μm, more preferably 18 to 50 μm. The intermediate layer (C) is preferably 2 to 15 μm, more preferably 2 to 13 μm.

[Manufacturing method of laminated film]
The method for producing the easily openable laminated film of the present invention is not particularly limited, but for example, each resin or resin mixture used for each layer is heated and melted by a separate extruder, and a coextrusion multilayer die method or a feed block method is used. After laminating the heat seal layer (A) / base material layer (B) or the heat seal layer (A) / intermediate layer (C) / base material layer (B) in a molten state by a method such as Examples thereof include a coextrusion method of forming into a film by a die-chill roll method or the like. The coextrusion method is preferable because the thickness ratio of each layer can be adjusted relatively freely, and a laminated film having excellent hygiene and cost performance can be obtained. When a resin having a large difference between the melting point and Tg is laminated, the appearance of the film may be deteriorated during coextrusion processing, or it may be difficult to form a uniform layer structure. In order to suppress such deterioration, the T-die chill roll method, which can perform melt extrusion at a relatively high temperature, is preferable.

Further, when printing or laminating on the surface of the base material layer (B), it is preferable to perform surface treatment on the base material layer (B) in order to improve the adhesiveness with the printing ink or the adhesive. Examples of such surface treatments include corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, surface oxidation treatment such as ozone / ultraviolet treatment, and surface unevenness treatment such as sandblasting. Corona treatment is preferable.

[Laminate film]
Since the laminated film of the present invention can be suitably used as a lid material for various packaging containers, it is also preferable to laminate a laminated base material on the base material layer (A) to form a laminated film. The laminated base material is not particularly limited, but is generally a stretched base film because it can secure strength that does not break, heat resistance at the time of heat sealing, and improve the design of printing. Is preferable. As the stretched base film, a biaxially stretched polyester film, a biaxially stretched nylon film, a biaxially stretched polypropylene film and the like can be used, but in terms of breaking strength, transparency and the like, a biaxially stretched polyester film and a biaxially stretched nylon film can be used. Is more preferable. The base film may be easily torn or antistatic treated, if necessary.

The method for producing the laminated film is not particularly limited, and examples thereof include a method of laminating a laminated base material on the base layer (A) layer of the laminated film. Examples of the method for laminating a laminated base material on the laminated film of the present invention include a dry laminating method, a thermal laminating method, a multilayer extrusion coating method, and the like, and among these, the dry laminating method is more preferable. Further, examples of the adhesive used for laminating the laminated film and the laminated base material in the dry laminating method include a polyether-polyurethane-based adhesive and a polyester-polyurethane-based adhesive. Further, it is preferable to apply a corona discharge treatment to the surface of the surface layer before laminating the coextruded laminated film of the present invention and the base material because the adhesion to the base material is improved.

[Packaging]
The laminated film and the laminated film of the present invention can be suitably used as various packaging materials. In particular, it can be suitably used for dairy products, yogurt, jelly, tofu, pickle containers, kimchi containers, sweets containers, rice containers, instant noodle containers, etc., and is particularly preferably used as a lid material for packaging containers having openings. can.

As the packaging container having an opening, various packaging containers such as polylactic acid-based resin, polyolefin-based resin, paper / polybutylene succinate-based resin, paper / polyolefin-based resin, and polyethylene terephthalate can be used. The laminated film of the present invention can realize heat-sealing property and easy-opening property suitable for packaging containers of these various materials.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

(Preparation Example 1)
Ethylene-vinyl acetate copolymer resin (hereinafter abbreviated as EVA (1)) with a vinyl acetate-derived component content of 30% and MFR of 3.0 g / 10 min and a cyclic aliphatic petroleum resin (Arcon P-100 manufactured by Arakawa Chemical Co., Ltd.) Hereinafter, abbreviated as petroleum resin (1)) is used at EVA (1) / petroleum resin (1) (mass ratio) = 85/15, and erucic acid amide (blocking inhibitor) is used with respect to the total of these. And synthetic zeolite having an average particle size of 3 μm are mixed so that the amount of erucic acid amide is 2000 ppm and the amount of synthetic zeolite is 5000 ppm. Pellets of EVA resin composition were obtained.

(Example 1)
The following resins were used as the resin components forming the heat seal layer (A) and the base material layer (B), respectively, to prepare a resin mixture forming each layer. The resin mixture forming each layer is melted and supplied to two extruders, and the thickness of each layer of the laminated film formed by the heat seal layer (A) / base material layer (B) is 10 μm / 40 μm. It is supplied to a T-die-chill roll method co-extruded multilayer film manufacturing apparatus (feed block and T-die temperature: 230 ° C.) having a feed block, co-extruded, and cooled with a water-cooled metal cooling roll at 40 ° C. , A laminated film having a total thickness of 50 μm was formed.
Heat seal layer (A): Polybutylene succinate resin (PTTMCC Biochem "FD92PB", density: 1.24 g / cm ³ , melting point 84 ° C., MFR: 4 g / 10 minutes (190 ° C., 21.18N); Hereinafter referred to as "PBSA (1)") 50 parts by mass, polylactic acid resin ("4043D" manufactured by Nature Works, Inc., density: 1.24 g / cm ³ , MFR: 6 g / 10 minutes (190 ° C., 21.18 N). ); Hereinafter referred to as "PLA (1)") 50 parts by mass of resin mixture.
Base material layer (B): Linear low-density polyethylene (“UBE polyethylene 2040” manufactured by Ube-Maruzen Polyethylene Co., Ltd., density: 0.920 g / cm ³ , melting point 110 ° C., MFR: 4 g / 10 minutes (190 ° C., 21) .18N); Hereinafter referred to as "PE (1)") 100 parts by mass.

(Example 2)
The following resins were used as the resin components forming the heat seal layer (A), the base material layer (B), and the intermediate layer (C), respectively, to prepare a resin mixture forming each layer. The resin mixture forming each layer is melted and supplied to each of the three extruders, and the thickness of each layer of the laminated film formed by the heat seal layer (A) / intermediate layer (C) / base material layer (B). It is supplied to a co-extruded multilayer film manufacturing apparatus (feed block and T-die temperature: 230 ° C.) of the T-die / chill-roll method having a feed block so as to have a diameter of 3 μm / 5 μm / 22 μm, and co-extruded to 40 ° C. The film was cooled with a water-cooled metal cooling roll to form a laminated film having a total thickness of 30 μm.
Heat seal layer (A): A resin mixture of 25 parts by mass of PBSA (1) and 75 parts by mass of PLA (1).
Base material layer (B): 100 parts by mass of PE (1).
Intermediate layer (C): Acid-modified olefin copolymer (“SF730” manufactured by Mitsui Chemicals, Inc., density 0.902 ^{g / cm 3} , MFR: 2.7 g / 10 minutes (190 ° C., 21.18N); Adhesive resin (1) ") 100 parts by mass.

(Example 3)
The following resin is used as the resin component forming the heat seal layer (A), and the thickness of each layer of the laminated film formed by the heat seal layer (A) / intermediate layer (C) / base material layer (B). A laminated film having a total thickness of 30 μm was formed in the same manner as in Example 2 except that the thickness was 4 μm / 5 μm / 21 μm.
Heat seal layer (A): A resin mixture of 50 parts by mass of PBSA (1) and 50 parts by mass of PLA (1).

(Example 4)
The following resin is used as the resin component forming the heat seal layer (A), and the thickness of each layer of the laminated film formed by the heat seal layer (A) / intermediate layer (C) / base material layer (B). A laminated film having a total thickness of 30 μm was formed in the same manner as in Example 2 except that the thickness was set to 5 μm / 5 μm / 20 μm.
Heat seal layer (A): Polybutylene succinate copolymer (PTTMCC Biochem "FZ91PB", density: 1.26 g / cm ³ , melting point 115 ° C, MFR: 5 g / 10 minutes (190 ° C, 21.18N) ); Hereinafter referred to as "PBS (1)") A resin mixture of 50 parts by mass and PLA (1) by 50 parts by mass.

(Example 5)
The following resin is used as a resin component for forming the base material layer (B) and the intermediate layer (C), and the heat seal layer (A) / intermediate layer (C) / base material layer (B) is formed. A laminated film having a total thickness of 30 μm was formed in the same manner as in Example 3 except that the thickness of each layer of the laminated film was 5 μm / 5 μm / 20 μm.
Base material layer (B): Linear low density biopolyethylene (“Biopolyethylene SLH218” manufactured by BRASCEM, density: 0.920 g / cm ³ , melting point 110 ° C., MFR: 4 g / 10 minutes (190 ° C., 21. 18N); Hereinafter referred to as "PE (2)") 100 parts by mass.
Intermediate layer (C): 100 parts by mass of the EVA-based resin composition adjusted in the above (Adjustment Example 1).

(Example 6)
The following resin is used as the resin component forming the heat seal layer (A), and the thickness of each layer of the laminated film formed by the heat seal layer (A) / intermediate layer (C) / base material layer (B). A laminated film having a total thickness of 30 μm was formed in the same manner as in Example 2 except that the thickness was 5 μm / 6 μm / 19 μm.
Heat seal layer (A): A resin mixture of 70 parts by mass of PBS (1) and 30 parts by mass of PLA (1).

(Comparative Example 1)
The following resin is used as the resin component forming the heat seal layer (A), and the thickness of each layer of the laminated film formed by the heat seal layer (A) / intermediate layer (C) / base material layer (B). A laminated film having a total thickness of 30 μm was formed in the same manner as in Example 2 except that the thickness was set to 3 μm / 3 μm / 24 μm.
Heat seal layer (A): PLA (1) 100 parts by mass.

(Comparative Example 2)
Using PBSA (1), a single-layer film having a film thickness of 30 μm was obtained.

(Comparative Example 3)
Using PLA (1), a single-layer film having a film thickness of 30 μm was obtained.

(Comparative Example 4)
Using PE (1), a single-layer film having a film thickness of 30 μm was obtained.

The films obtained in the above Examples and Comparative Examples were evaluated as follows. The results obtained are shown in the table below.

(Making a laminated film)
A biaxially stretched polyethylene terephthalate (PET) film (thickness 12 μm) was attached to the substrate layer (B) side surface or the single layer film surface of the multilayer films obtained in the above Examples and Comparative Examples by dry lamination. A laminated film was obtained. At this time, as the adhesive for dry lamination, a two-component curable adhesive (polyester adhesive "LX63F" and curing agent "KP90") manufactured by DIC Corporation was used.

(Evaluation of transparency)
The haze of the films obtained in the above Examples and Comparative Examples was measured with a haze meter NDH5000 manufactured by Nippon Denshoku Kogyo Co., Ltd. in accordance with JIS K7105, and the transparency was evaluated.
◯: 20% or less.
×: 20% or more.

(Evaluation of rigidity)
The 1% secant modulus measured below of the films obtained in the above Examples and Comparative Examples was evaluated as rigidity (hardness) according to the following criteria. For the measurement of the 1% secant modulus, a film cut out at a length of 300 mm × a width of 25.4 mm (mark line spacing 200 mm) was used as a test piece so that the longitudinal direction was the film flow direction (vertical direction), and ASTM D- It was carried out under the condition of a tensile speed of 20 mm / min according to 882.
◯: 350 MPa or less.
X: 350 MPa or more.

(Evaluation of heat sealability (easy peelability) on various sheets)
A-PET sheet (thickness 500 μm) or PLA sheet (“4043D” manufactured by Nature Works, thickness 300 μm) obtained by producing the above-mentioned laminated film prepared in Examples and Comparative Examples was used at 80 to 130 ° C. Heat sealing was performed at each temperature in increments of 10 ° C. (0.2 MPa, 1.2 seconds). The seal sample is cut into strips of 15 mm and used as test pieces, and the test pieces are used in a constant temperature room at 23 ° C. and 50% RH using a tensile tester (manufactured by A & D Co., Ltd.) at a speed of 300 mm / min. After 180 ° peeling, the heat seal strength was measured and evaluated according to the following criteria.
⊚: Heat seal strength at all temperatures is 5N / 15mm or more.
◯: The temperature at which the heat seal strength is 5 N / 15 mm or more is more than half (3 to 5). (The temperature in the table is the lowest temperature of 5N / 15mm or more)
Δ: The temperature at which the heat seal strength was 5 N / 15 mm or more was less than half (1-2).
X: At all temperatures, the heat seal strength is 5 N / 15 mm or less or the seal surface does not peel off, and the film breaks.

(Evaluation of heat sealability (easy opening) to various containers)
The laminate film obtained above is used as a lid material (heat seal layer (A), a round cup container having a flange portion having an outer diameter of 70 mm, a depth of 50 mm, and a width of 5 mm made of APET, PLA, and a PBS resin (25 μm). Heat the flange of a round cup paper container having a flange with an outer diameter of 70 mm, a depth of 50 mm, and a width of 5 mm, which is made of plastic, under the conditions of a sealing temperature of 150 ° C, a sealing pressure of 0.2 MPa, and a sealing time of 1.5 seconds. Next, the heat-sealed sample was naturally cooled at 23 ° C., and then the heat-sealed portion was cut into strips having a width of 15 mm to form test pieces. Using (manufactured by A & D Co., Ltd.), 90 ° peeling was performed at a speed of 300 mm / min, and the heat seal strength was measured.
From the results of the heat seal strength measured above, the heat seal property in the paper container was evaluated according to the following criteria.
◯: Heat seal strength is 4 to 30 N / 15 mm.
X: The heat seal strength is less than 4N / 15 mm or the film does not peel off on the sealing surface and the film breaks.

(Evaluation of blocking resistance)
A load of 400 g was stored at 40 degrees for 1 month on 10 A-4 plates of the films prepared in Examples and Comparative Examples. After that, the strength of the adhered films was cut into strips with a width of 15 mm to make test pieces, and the test pieces were used in a constant temperature room at 23 ° C and 50% RH using a tensile tester (manufactured by A & D Co., Ltd.). , 90 ° peeling was performed at a speed of 300 mm / min, and the blocking strength was measured.
◯: 100 g / 15 mm or less.
X: 100 g / 15 mm or more.

(Evaluation of film forming property)
During the production of the films produced in Examples and Comparative Examples, the state of gel and hole generation was confirmed.
◯: The number of holes is 1 / m ² or less.
X: The number of holes is 1 / m ² or less.

(Impact resistance evaluation)
Specimens obtained by allowing the films obtained in Examples and Comparative Examples to stand in a constant temperature room adjusted to 0 ° C. for 4 hours were prepared. For each test piece, a 1.5-inch head was attached to the tip of the pendulum using a BU-302 type film impact tester manufactured by Tester Sangyo, and the impact strength by the film impact method was measured.
◯: Impact strength is 0.10 (J) or more ×: Impact strength is less than 0.10 (J)

As is clear from the above table, the laminated film of the present invention of Examples 1 to 6 has heat-sealing property and easy-opening property suitable for various sheets and containers in a wide temperature range, and is used for packaging. It had the appropriate rigidity, film forming property, impact resistance, and the like.

Claims (11)

A laminated film having a heat seal layer (A) and a base material layer (B), one surface layer being the surface of the heat seal layer (A) and the other surface layer being the surface of the base material layer (B).
The heat seal layer (A) has a melt flow rate (190 ° C., 21.18N) of 0. The 5 to 20 g / 10 min polylactic acid resin (a1) and the melt flow rate (190 ° C., 21.18 N) contained 0.5 to 30 g / 10 min of polybutylene succinate resin (a2).
A laminated film characterized in that the base material layer (B) contains a polyolefin-based resin as a main resin component. The content ratio of the polylactic acid-based resin (a1) and the polybutylene succinate-based resin (a2) in the heat-sealed layer (A) is 75 / in the mass ratio represented by (a1) / (a2). The laminated film according to claim 1, which is 25 to 25/75. An intermediate layer (C) is provided between the heat-sealed layer (A) and the base material layer (B), and the intermediate layer (C) is an acid-modified olefin resin or an ethylene-α-olefin copolymer rubber. The laminated film according to claim 1 or 2, which comprises. 13. The laminated film according to any one. The laminated film according to any one of claims 1 to 4, wherein the thickness of the heat seal layer (A) is 5 to 30% in total thickness, and the thickness of the base material layer (B) is 70 to 95% of the total thickness. The invention according to any one of claims 1 to 5, wherein the heat seal layer (A) has a thickness of 2 to 15 μm. Laminated film. The laminated film according to any one of claims 1 to 6 , which has a thickness of 20 to 70 μm. A packaging material made of the laminated film according to any one of claims 1 to 7. A lid material made of the laminated film according to any one of claims 1 to 7. A lid material comprising laminating a base material on the base material layer (B) of the laminated film according to any one of claims 1 to 7. The method for producing a laminated film according to any one of claims 1 to 7, which is a coextrusion method. A method for manufacturing a laminated film.