JP6291766B2 - Easy-open laminated film, easy-open laminated film and lid - Google Patents

Description

  The present invention provides a laminate film and a laminate film that exhibit excellent easy-openability for adherends such as heat-sealing portions of packaging containers, regardless of the sealing temperature, and can be suitably used as cover materials for packaging containers. About.

  In recent years, with the trend toward universal design in medical device packaging and food packaging, as a consideration for the socially vulnerable (elderly, infants, people with disabilities, etc.), methods that consumers can easily open, such as easy opening Is being emphasized.

  As an easily openable lid material, a lid material using a wax-like resin generally called a hot melt agent as a sealant is often used (see, for example, Patent Document 1). In the scene where the lid provided in Patent Document 1 is actually used, the seal temperature may be raised in order to suppress the occurrence of a seal failure due to the biting of the contents, but the seal temperature is raised. As a result, there is a problem that the opening strength is increased and the easy opening property is not exhibited.

JP 2006-089521 A

  In view of the above situation, the problem of the present invention is that the adherend having a heat seal portion made of a thermoplastic resin material has excellent easy-openability regardless of the seal temperature, It is providing the laminated film suitable for a use, and the laminated film which laminated this laminated film on the base film.

  As a result of earnest research to solve such problems, the present inventor has a heat seal layer containing an ethylene-vinyl acetate copolymer and / or an ethylene-methyl methacrylate copolymer, and a specific ethylene-based resin as a main component. The present inventors have found that a laminated film having a laminated layer to solve the above-mentioned problems has completed the present invention.

  That is, the present invention includes a heat seal layer (A) containing an ethylene-vinyl acetate copolymer and / or an ethylene-methyl methacrylate copolymer, and a melt flow rate at 190 ° C. of 0.1 to 1.0 g / min. An easy-open laminate film having a laminate layer (B) mainly composed of an ethylene-based resin, and a stretched base film is laminated and bonded to the laminate layer of the laminate film via an adhesive It is an object of the present invention to provide an easy-open laminate film characterized by the above.

  The laminated film and laminated film of the present invention can surely exhibit easy-opening properties based on interfacial peeling even if there is a difference in heat seal temperature. Thereby, even if the sealing temperature is increased to prevent biting of the contents, it is easy to open, so that it can be suitably used as a lid for packaging containers.

  Below, each part which comprises the laminated | multilayer film and laminated film of this invention is explained in full detail.

  The heat seal layer (A) in the present invention contains an ethylene-vinyl acetate copolymer and / or an ethylene-methyl methacrylate copolymer. The ethylene-vinyl acetate copolymer and / or the ethylene-methyl methacrylate copolymer is not particularly limited, but, among them, the vinyl acetate and / or methyl methacrylate-derived component content is 5 to 35 mass%, and the melt flow at 190 ° C. A rate (MFR) of 0.5 to 30 g / 10 min is preferred. Since the adhesiveness to the thermoplastic resin material constituting the adherend is good and the multilayer moldability with the laminate layer (B) described later is excellent, the vinyl acetate-derived component content is 7 to 25% by mass, MFR 1.0 to The thing of 10 g / 10min is more preferable. Moreover, as ethylene-vinyl acetate copolymer and / or ethylene-methyl methacrylate copolymer, unsaturated carboxylic acids such as (meth) acrylic acid and maleic anhydride and anhydrides thereof were introduced as an adhesive function. It may be a modified product.

  The heat seal layer (A) may contain various tackifiers. Examples of the tackifier include aliphatic hydrocarbon resins (including alicyclic hydrocarbon resins), aromatic hydrocarbon resins, rosins, and polyterpene resins.

  Examples of the aliphatic hydrocarbon resin include polymers having a main component of a monoolefin or diolefin having 4 to 5 carbon atoms such as butene-1, butadiene, isobutylene, and 1,3-pentadiene, cyclopentadiene, and spent. Examples thereof include a resin obtained by polymerizing a cyclic monomer such as a resin obtained by polymerizing a diene component in a C4 to C5 fraction after cyclization and dimerization, and a resin obtained by endocyclic hydrogenation of an aromatic hydrocarbon resin. Examples of the aromatic hydrocarbon resin include resins mainly composed of vinyl aromatic hydrocarbons such as α-methyltoluene, vinyltoluene, and indene. Examples of rosins include rosin, polymerized rosin, rosin glycerol ester, hydrogenated rosin glycerol ester, polymerized rosin glycerol ester, rosin pentaerythritol ester, rosin pentaerythritol ester hydrogenated, rosin Examples thereof include a polymer of pentaerythritol ester. Examples of the polyterpene resin include hydrogenated terpene resin, terpene-phenol copolymer resin, dipentene polymer, α-pinene polymer, β-pinene polymer, α-pinene-phenol copolymer resin, and the like.

  Examples of the tackifier include synthetic resin-based tackifiers other than those described above, for example, acid-modified C5 petroleum resin, C5 / C9 copolymer petroleum resin, xylene resin, coumarone indene resin and the like.

  As the tackifier, an aliphatic hydrocarbon resin can be preferably used since it is excellent in low odor, transparency, moldability and the like.

  The blending ratio of the ethylene-vinyl acetate copolymer and / or ethylene-methyl methacrylate copolymer and the tackifier in the heat seal layer (A) is excellent in adhesion to the thermoplastic resin material constituting the adherend. Since the film forming property is good, a range in which the mass ratio (copolymer / tackifier) is 97/3 to 70/30 is preferable.

  In the heat seal layer (A), an ethylene-vinyl acetate copolymer and / or an ethylene-methyl methacrylate copolymer and a tackifier can be blended with a styrene resin. Examples of the styrene resin include a styrene homopolymer; an impact-resistant styrene resin obtained by graft polymerization of a styrene monomer to a synthetic rubber such as butadiene rubber or styrene-butadiene rubber. The blend of the styrene resin is particularly effective for the adherend of the styrene resin material, the MFR of 1 to 40 g / 10 min is preferable, and the one of 5 to 20 g / 10 min is more preferable because of excellent molding processability. .

  The blending ratio in the case of blending the styrenic resin with the heat seal layer (A) is particularly effective with respect to the adherend of the styrenic resin material, and there is little decrease in transparency. The polymer / tackifier / styrene polymer) is preferably in the range of 50 to 92/3 to 30/5 to 20.

  The laminate layer (B) in the present invention essentially comprises an ethylene resin having a melt flow rate at 190 ° C. of 0.1 to 1.0 g / min as a main component. Here, the main component means that it is essential that the resin component constituting the layer (B) contains a specific ethylene resin at 65% by mass or more, preferably 80% by mass or more. It means a specific ethylene resin.

  The ethylene-vinyl acetate copolymer and / or the ethylene-methyl methacrylate copolymer used in the heat seal layer (A) described above increases the sealing temperature, causing a resin flow, and the seal portion (where heat is applied). There exists a tendency for the thickness of a seal layer (A) to reduce. For this reason, it is considered that the thickness of the portion in contact with the seal portion is relatively increased, and as a result, there is a problem that the adhesive strength is increased. In the present invention, the resin used for the laminate layer (B) to be laminated on the heat seal layer (A) is a resin having poorer fluidity (= MFR is smaller) than a general resin conventionally used for films. And ethylene-vinyl acetate copolymer and / or ethylene-vinyl acetate copolymer of the heat seal layer (A) and / or ethylene-vinyl acetate copolymer and / or ethylene-methyl methacrylate copolymer. Alternatively, by suppressing the resin flow of the ethylene-methyl methacrylate copolymer, it is possible to effectively control the improvement of the adhesive strength with the adherend when the sealing temperature is increased, and thus, the expression of stable easy opening. This is an effect.

The above-mentioned ethylene-based resin may have an MFR of 0.1 to 1.0 g / min, and is not particularly limited in other physical properties, but from the viewpoint of good film formability, It is preferable to use 0.910 to 0.960 g / cm ³ of polyethylene, and it is particularly preferable to use linear polyethylene having a density of 0.930 to 0.950 g / cm ³ .

  As said ethylene-type resin, even if it consists of a single ethylene-type resin, you may mix and use the ethylene-type resin from which several density and MFR differ. At this time, MFR needs to be in the range of 0.1 to 1.0 g / min as defined in the present invention by MFR as a mixture.

  As long as the MFR specified in the present invention is satisfied, a resin other than the ethylene-based resin may be used in combination for the laminate layer (B). The resin that can be used at this time is preferably an olefin resin from the viewpoint of compatibility with the ethylene resin, and in particular, ethylene-vinyl acetate used in the propylene-ethylene copolymer or the heat seal layer (A) described above. A copolymer, an ethylene-methyl methacrylate copolymer, or an acid-modified ethylene resin may be used.

  In the present invention, as described above, any laminated film having a heat seal layer (A) and a laminate layer (B) may be used, and an intermediate layer (C) is further provided between the layer (A) and the layer (B). May be a laminated film.

  As the resin that can be used for the intermediate layer (C), it is preferable to use an olefin resin from the viewpoint of easy lamination with the heat seal layer (A) and the laminate layer (B) by a coextrusion lamination method. In particular, from the viewpoint of interlayer adhesion, it is preferable to use an ethylene-based resin.

  The ethylene resin used for the intermediate layer (C) may be the same as or different from the ethylene resin used for the laminate layer (B), and the MFR is particularly 0.1 to 5.0 g / min. It is preferable to use an ethylene resin having relatively poor fluidity from the viewpoint of not impairing the effects of the present invention. In this intermediate layer (C), so-called recovered products can be mixed and used.

  Although the total thickness of the laminated film of the present invention, the thickness of the heat seal layer (A) and the laminate layer (B) are not particularly limited, the total thickness is usually 20 to 100 μm, and the thickness of the heat seal layer (A) is When the thickness ratio of the heat seal layer (A) to 2 to 50 μm and the total thickness is in the range of 10 to 50%, it is preferable from the viewpoint of excellent balance between adhesion to the adherend and easy opening.

  The production method of the laminated film of the present invention is not particularly limited, but various methods such as a coextrusion lamination molding method, for example, a melt extrusion using two or more extruders, a coextrusion multilayer die method, a feed block method and the like. After laminating in a molten state by a coextrusion method, a method of processing into a long wound film by a method such as inflation or a T die / chill roll method is preferred, and a coextrusion method using a T die is more preferred.

  In general, the laminated film of the present invention is desirably laminated with a stretched substrate film because it can ensure strength that does not break, ensure heat resistance at the time of heat sealing, improve the design of printing, and the like. Examples of the base film to be laminated include a biaxially stretched polyester film, a biaxially stretched nylon film, and a biaxially stretched polypropylene film. A biaxially stretched polyester film is more preferable in terms of breaking strength and transparency. The base film may be subjected to easy tearing treatment or antistatic treatment as required. As a method for laminating the laminated film and the substrate film, a composite technique such as dry lamination, extrusion lamination, or heat lame may be used.

  In the laminated film of the present invention, the laminate layer (A) may be subjected to a surface treatment such as corona treatment for the purpose of improving the suitability of the laminate. An agent, an ultraviolet absorber, a light stabilizer, an antistatic agent, a conductive agent and the like may be added or coated as appropriate. As these additives and coating agents, it is preferable to use various additives and coating agents for olefin resins.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the examples, “%” and “part” are based on mass unless otherwise specified.

Synthesis Example 1 [Production of resin composition for heat seal layer (A)]
Ethylene-vinyl acetate copolymer resin (vinyl acetate-derived component content 15%, MFR 4.0 g / 10 min., Hereinafter abbreviated as EVA1) and cycloaliphatic petroleum resin (Arukawa Chemical Alcon P-100, hereinafter). Abbreviated as petroleum resin 1) EVA1 / petroleum resin 1 (mass ratio) = 85/15, erucic acid amide (antiblocking agent) and synthetic zeolite having an average particle size of 3 μm with respect to the total of these, The mixture was mixed so that the erucic acid amide was 2000 ppm and the synthetic zeolite was 5000 ppm, melt-kneaded by a single screw extruder having a diameter of 40 mm, and pelletized to obtain a pellet of the resin composition 1 for the heat seal layer (A). .

Synthesis example 2 (same as above)
An ethylene-methyl methacrylate copolymer resin (methyl methacrylate-derived component content 15%, MFR 4.0 g / 10 min., Hereinafter abbreviated as EMMA1) and petroleum resin 1 are combined with EMMA1 / petroleum resin 1 (mass ratio) = 85. Erucamide (blocking inhibitor) and synthetic zeolite having an average particle size of 3 μm were mixed with the total of these so that erucic acid amide was 2000 ppm and synthetic zeolite was 5000 ppm. After melt-kneading with a shaft extruder, the mixture was pelletized to obtain pellets of the resin composition 2 for the heat seal layer (A).

Example 1
As the resin for the easy peel layer (A), the resin obtained in Synthesis Example 1 was used. As a resin for the laminate layer (B), an ethylene-hexene copolymer [MFR (190 ° C.) 0.9 g / 10 min, density 0.944 g / cm ³ ] polymerized using a metallocene catalyst (hereinafter referred to as metallocene LLDPE ( b)) was used. For the intermediate layer (C), the same resin as that for the laminate layer (B) was used. Resin is supplied to each of the intermediate layer extruder (40 mm diameter), the laminate layer extruder (30 mm diameter), and the heat seal layer extruder (30 mm diameter), and a T-die at an extrusion temperature of 280 ° C. by co-extrusion. To (A) / (C) / (B) are extruded so that each layer has a thickness of 10 μm / 15 μm / 5 μm, cooled with a 40 ° C. water-cooled metal cooling roll, and subjected to corona discharge treatment on the surface of the laminate layer. The film was wound on a roll and aged in a aging room at 35 ° C. for 48 hours to obtain a laminated film of the present invention having a total thickness of 30 μm.

  The obtained laminated film was bonded using a biaxially stretched polyester film 12 μm and a dry laminate adhesive and aged at 40 ° C. for 36 hours, then cut into 10 cm × 10 cm, a polypropylene round injection molding cup, and heat The upper heat seal mold is adjusted to a predetermined temperature using a cup sealer (Shinwa Machine cup sealer) with the seal surface facing the polypropylene container flange side. Heat sealed.

  The outer film part of the heat-sealed flange part was gripped by the push-pull gauge tip, and the maximum strength when the lid member was peeled off at an angle of 45 degrees from the flange horizontal plane was defined as the opening strength.

Example 2
As a resin for the laminate layer (B) and the intermediate layer (C), an ethylene-hexene copolymer polymerized using a metallocene catalyst [MFR (190 ° C.): 0.4 g / 10 min, density: 0.944 g / cm ³ (Hereinafter referred to as metallocene LLDPE (a)) was used to obtain a laminated film of Example 2 in the same manner as in Example 1.

Example 3
A laminated film of Example 3 was obtained in the same manner as in Example 1 except that extrusion was performed so that the thickness of each layer was 40 μm / 30 μm / 10 μm.

Example 4
As a resin for the laminate layer (B) and the intermediate layer (C), metallocene LLDPE (a), ethylene-hexene copolymer polymerized using a metallocene catalyst [MFR (190 ° C.) 4.0 g / 10 min, density 0.944 g / cm ³ ] (hereinafter referred to as metallocene LLDPE (c)) and low density polyethylene [MFR (190 ° C.) 0.5 g / 10 min, density 0.92 g / cm ³ ] (hereinafter referred to as LDPE (a)). The laminated film of Example 4 was obtained in the same manner as in Example 1 except that the mixture was mixed so that the ratio was 50/30/20 and the MFR was about 0.7 g / 10 min.

Example 5
A laminated film of Example 5 was obtained in the same manner as in Example 1 except that the resin obtained in Synthesis Example 2 was used as the resin for the heat seal layer (A).

Example 6
As the resin for the intermediate layer (C), an ethylene-butene copolymer polymerized using a metallocene catalyst [MFR (190 ° C.) is 3 g / 10 min, density is 0.880 g / cm ³ ] (hereinafter referred to as metallocene LLDPE (d)) The laminated film of Example 6 was obtained in the same manner as in Example 1 except that the thickness of each layer (A) / (C) / (B) was extruded to 10 μm / 10 μm / 10 μm. Obtained.

Comparative Example 1
A laminated film of Comparative Example 1 was obtained in the same manner as in Example 1 except that only metallocene LLDPE (c) was used as the resin for the laminate layer (B) and the intermediate layer (C).

Comparative Example 2
A laminated film of Comparative Example 2 was obtained in the same manner as in Example 1 except that the resin composition 1 for the heat seal layer (A) was used as the resin for the laminate layer (B) and the intermediate layer (C).

  Using the laminated film obtained in the comparative example, a laminated film was obtained in the same manner as in the example, and the same evaluation was performed. It shows in Table 1 about the opening intensity | strength in an Example and a comparative example.

  The laminated films of Examples 1 to 6 showed a value of 10 to 34 N in the measurement of the opening strength, and showed a good opening property at a heat seal temperature of 160 to 190 ° C. On the other hand, in the measurement of the opening strength using the laminated film obtained in Comparative Example 1 and Comparative Example 2, it could not be opened in heat sealing at 180 ° C. and 170 ° C., respectively.

Claims (10)

An easy-opening unstretched laminated film and an easy-opening laminated film in which a stretched base film is laminated and bonded,
The easily openable unstretched laminated film has a heat seal layer (A) containing an ethylene-vinyl acetate copolymer and / or an ethylene-methyl methacrylate copolymer, and a melt flow rate at 190 ° C. of 0.1 to 1. An easily openable unstretched laminated film having a laminate layer (B) mainly composed of ethylene resin of 0.0 g / 10 min ;
An easily openable laminate film, wherein a stretched base film is laminated and adhered onto the laminate layer (B) of the easily openable unstretched laminate film. The easy-open laminate film according to claim 1, further comprising a tackifier in the heat seal layer (A) . The easily openable laminate film according to claim 1 or 2, wherein a resin used for the heat seal layer (A) has a melt flow rate at 190 ° C of 0.5 to 30 g / 10 min . The easy-open laminate film according to any one of claims 1 to ³ , wherein a density of the ethylene-based resin used for the laminate layer (B) is in a range of 0.910 to 0.960 g / cm ³ . The easily openable laminate film according to any one of claims 1 to 4, further comprising an intermediate layer (C) between the heat seal layer (A) and the laminate layer (B) . The easily openable laminate film according to claim 5, wherein the intermediate layer (C) is mainly composed of an ethylene-based resin . The easily openable laminate film according to any one of claims 1 to 6, wherein the easily openable unstretched laminated film is produced using a coextrusion lamination method . The total thickness of the easily openable laminated film is in the range of 20 to 100 [mu] m, easily openable of any one of claims 1 to 7 thickness ratio of the heat seal layer (A) is in the range of 10-50% Laminate film. A lid for a packaging container, wherein the easy-open laminate film according to any one of claims 1 to 8 is used. The lid material according to claim 9, wherein a portion of the packaging container that contacts the lid material is made of a polyolefin resin.