JP5302679B2 - Film, heat-shrinkable film, and molded article using the heat-shrinkable film, heat-shrinkable label, and container using or fitted with the molded article - Google Patents

Abstract

Disclosed is a film having at least one layer mainly composed of a polyolefin resin (A) and further containing a polylactic acid resin (B) and an acrylic resin (C). The film has excellent transparency and places little burden on the environment.

Description

  The present invention relates to a film having a low environmental load and excellent transparency, a heat-shrinkable film, and a molded article using the heat-shrinkable film, a heat-shrinkable label, and the molded article, or the label mounted thereon. Related to the container.

  Currently, soft drinks such as juice and alcoholic drinks such as beer are sold in a state of being filled in containers such as bottles and plastic bottles. At that time, in order to differentiate from other products and improve the visibility of the products, a heat-shrinkable label printed on the outside of the container is often attached. As a material for the heat-shrinkable label, a vinyl chloride resin, a styrene resin, a polyester resin, or the like is usually used. A heat-shrinkable film formed of these resins has high transparency, gloss, rigidity, and excellent low-temperature shrinkage characteristics, and therefore can be suitably used as a heat-shrinkable film.

  On the other hand, polyolefin resin is a preferable material with less environmental load that has less problems with combustion-generated gases and endocrine disrupting chemical substances, which are so-called environmental hormones, and has a low specific gravity, leading to a reduction in the weight of garbage. However, this heat-shrinkable film made of polyolefin resin has insufficient film rigidity and low-temperature shrinkability, lacks shrinkage at the time of heat shrinkage, and further spontaneous shrinkage (film at a temperature slightly higher than room temperature, for example, in summer) There is a problem that it is likely to shrink slightly before the original use) (see, for example, Patent Document 1).

  Polylactic acid resins are also attracting attention as materials with a low environmental impact. The polylactic acid-based resin is a plant-derived resin that uses lactic acid obtained by fermentation of starch as a raw material, and can save fossil resources and suppress emission of carbon dioxide. In addition, polylactic acid resin is a material excellent in physical properties such as rigidity and transparency. However, the polylactic acid resin has a drawback of being brittle. In addition, the heat-shrinkable film made of a polylactic acid-based resin has a sharp shrinkage rate change with respect to the shrinkage temperature, and thus there is a problem in terms of shrinkage finish such that uniform shrinkage is difficult to obtain and shrinkage unevenness occurs. (For example, see Patent Documents 2, 3 and 4).

  In view of the above situation, a mixed resin composition of a polylactic acid resin and a modified polyolefin resin has been studied (for example, see Patent Documents 5, 6 and 7). However, the difference in refractive index between the polylactic acid-based resin and the polyolefin-based resin is large, and the sheet made of the obtained mixed resin composition has a problem that the transparency is remarkably deteriorated. In addition, the present invention uses a matrix as a biodegradable resin, and is mainly intended to improve both mechanical properties typified by impact strength and maintain biodegradability. It was difficult to obtain finish and stretch film-forming properties.

In addition, a sheet-like material comprising a polyolefin-based resin composition containing a polyolefin-based resin as a base component, a polylactic acid-based synthetic resin component, and a vinyl acetate / ethylene copolymer is described (for example, Patent Documents). 8). However, the invention is mainly intended to prevent adhesion to the roll surface and maintain biodegradability when processing into a sheet-like material by a roll. There was a problem of lacking in stretchability and stretchability.
JP 2003-253008 A JP 2006-066332 A JP 2003-205548 A JP 2001-354786 A JP 2005-68232 A Japanese Patent Laid-Open No. 5-179110 JP 9-316310 A Japanese Patent Laid-Open No. 2003-301077

  This invention is made | formed in view of the subject of the said prior art, and the objective of this invention is that there is little environmental impact and provides the film excellent in transparency.

  Another object of the present invention is to provide a heat-shrinkable film suitable for uses such as shrink wrap, shrink-bound wrap, and shrink label with low environmental burden and excellent shrinkage characteristics and transparency.

  Furthermore, the present invention relates to a molded product using the heat-shrinkable film suitable for applications such as shrink-wrapping, shrink-bound packaging, and shrinkable labels, a heat-shrinkable label, and a container equipped with the molded product or heat-shrinkable label. The purpose is to provide.

  As a result of intensive studies on the composition, blending ratio, and processing conditions of the polyolefin-based resin, the polylactic acid-based resin, and the acrylic-based resin, the present inventors have succeeded in obtaining a film that can solve the problems of the prior art. The present invention has been completed.

1st this invention contains polyolefin-type resin (A) as a main component, and polylactic acid-type resin (B) is 1 mass part or more and 50 mass parts or less with respect to 100 mass parts of this polyolefin resin (A). , Having at least one layer containing 1 part by mass or more and 50 parts by mass or less of the acrylic resin (C), and the acrylic resin (C) is a methyl methacrylate homopolymer or methyl methacrylate and methacrylic acid A film characterized by being a copolymer of at least one other vinyl monomer selected from ethyl, butyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid, and methacrylic acid It is.

  Here, in the present invention, when the term “film” is simply used, this term includes a stretched film, an unstretched film, and a heat-shrinkable film.

  In the first invention, the polyolefin resin (A) is any resin selected from the group consisting of a polyethylene resin, a polypropylene resin, an ethylene-vinyl acetate copolymer, or a mixed resin thereof. preferable.

  In 1st this invention, it is preferable that content of polylactic acid-type resin (B) is 1 to 50 mass parts with respect to 100 mass parts of polyolefin resin.

  In 1st this invention, it is preferable that content of acrylic resin (C) is 1 to 50 mass parts with respect to 100 mass parts of polyolefin resin.

  The film of the first aspect of the present invention preferably has front and back layers mainly composed of a polylactic acid resin (B) on both sides.

  The second present invention is a heat-shrinkable film (hereinafter, also referred to as “heat-shrinkable film of the present invention”) in which the film of the first present invention has heat-shrinkability.

  In the heat-shrinkable film of the second invention, it is preferable that the shrinkage rate in at least one direction when immersed in warm water at 80 ° C. for 10 seconds is 20% or more.

  The third aspect of the present invention is a molded article using the heat-shrinkable film of the second aspect of the present invention as a base material, a heat-shrinkable label, and a container equipped with the molded article and the heat-shrinkable label.

  According to the first aspect of the present invention, it is possible to provide a film having a low environmental load and excellent transparency. In addition, according to the second aspect of the present invention, it is possible to provide a heat-shrinkable film having a low environmental load and excellent in shrinkage characteristics and transparency.

  According to the third aspect of the present invention, the heat shrinkage can be fixed in a desired position regardless of the shape of the attachment, and there is no abnormality such as wrinkles, avatars, insufficient shrinkage, etc., and a beautiful appearance Containers equipped with adhesive labels, molded articles and heat-shrinkable labels can be provided.

  Hereinafter, the film of the present invention, a heat-shrinkable film, a molded product and a heat-shrinkable label using the heat-shrinkable film, and a container equipped with the molded product or the heat-shrinkable label (hereinafter referred to as “the present” The molded article of the invention "," label of the present invention "and" container of the present invention ") will be described in detail.

  In the present specification, “main component” is intended to allow other components to be included as long as the action and effect of the resin constituting each layer is not hindered. Further, this term does not limit the specific content, but it is 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass with respect to the total components of each layer. It is a component occupying a range of not less than 100% and not more than 100% by mass. Further, in this specification, the “main shrinkage direction” means a direction in which the thermal shrinkage rate is large between the longitudinal direction (longitudinal direction) of the film and the lateral direction (width direction) of the film. Means a direction corresponding to the outer circumferential direction, and “orthogonal direction” means a direction perpendicular to the main contraction direction.

[the film]
The film of the present invention has at least one layer containing a polyolefin resin (A) as a main component and containing a polylactic acid resin (B) and an acrylic resin (C).

<Polyolefin resin (A)>
In the present invention, the polyolefin resin used as the resin (A) is not particularly limited, but from the viewpoints of heat shrinkage properties, mechanical properties, and moldability, polyethylene resins, polypropylene resins, ethylene-vinyl acetate copolymer It is preferable to use a combination or a mixture thereof. Examples of preferable polyethylene resins, polypropylene resins, and ethylene-vinyl acetate copolymers used in the present invention are shown below.

The polyethylene resin used in the present invention is a high density polyethylene resin (HDPE) having a density of 0.94 g / cm ³ or more and 0.97 g / cm ³ or less, and a density of 0.92 g / cm ³ or more and 0.94 g / cm ^3. density polyethylene resins in less than ³ (MDPE), density of 0.92 g / cm ³ less than the low-density polyethylene resin (LDPE) or linear low density polyethylene resin (LLDPE). Among these, linear low density polyethylene resin (LLDPE) is particularly preferably used from the viewpoints of stretchability, impact resistance of the film, transparency, and the like.

  Examples of the linear low density polyethylene resin (LLDPE) include a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, preferably 4 to 12 carbon atoms. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 3-methyl-1-butene, 4- Examples include methyl-1-pentene. Of these, 1-butene, 1-hexene, and 1-octene are preferably used. Further, the α-olefin to be copolymerized may be used alone or in combination of two or more.

The density of the polyethylene resin is 0.80 g / cm ³ or more, preferably 0.85 g / cm ³ or more, more preferably 0.90 g / cm ³ or more, and 0.945 g / cm ³ or less, preferably 0. .935g / cm ³ or less, more preferably 0.925 g / cm ³ or less. If the density is 0.80 g / cm ³ or more, the waist (rigidity at room temperature) and heat resistance of the whole film are not significantly lowered, which is practically preferable. On the other hand, if the density is 0.945 g / cm ³ or less, the stretchability at a low temperature is maintained, and when configured as a heat-shrinkable film, heat shrinkage in a practical temperature range (70 ° C. or more and about 90 ° C. or less). It is preferable in that a sufficient rate can be obtained.

  Further, the melt flow rate (MFR) of the polyethylene resin is not particularly limited, but usually MFR (JIS K7210, temperature: 190 ° C., load: 21.18 N) is preferably 0.5 g / 10 min. As mentioned above, More preferably, it is 1.0 g / 10min or more, Preferably it is 15 g / 10min or less, More preferably, it is 10 g / 10min or less. The MFR of the polyethylene resin is preferably selected to have a viscosity close to that of the polylactic acid resin in order to obtain a film having a uniform thickness.

  Next, examples of the polypropylene resin include homopropylene resin, random polypropylene resin, block polypropylene resin, and ethylene-propylene rubber. Among these, a random polypropylene resin is particularly preferably used from the viewpoints of stretchability, transparency, rigidity, and the like.

  In the random polypropylene resin, the α-olefin copolymerized with propylene preferably includes those having 2 to 20 carbon atoms, more preferably 4 to 12 carbon atoms, such as ethylene, 1-butene, 1 -Pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene and the like can be exemplified. In the present invention, from the viewpoints of stretchability, heat shrinkage characteristics, impact resistance, transparency, rigidity, and the like of the film, a random polypropylene having an ethylene unit content of 2% by mass to 10% by mass as the α-olefin is particularly preferred. Preferably used. Further, the α-olefin to be copolymerized may be used alone or in combination of two or more.

  Further, the melt flow rate (MFR) of the polypropylene resin is not particularly limited, but usually MFR (JIS K7210, temperature: 230 ° C., load: 21.18 N) is preferably 0.5 g / 10. It is not less than 15 g / 10 minutes and more preferably not less than 1.0 g / 10 minutes and not more than 10 g / 10 minutes. The MFR of polypropylene is preferably selected to have a viscosity close to that of the polylactic acid-based resin in order to obtain a film having a uniform thickness.

  Next, as the ethylene-vinyl acetate copolymer, an ethylene-vinyl acetate copolymer having an ethylene unit content of 50 mol% to 95 mol%, preferably 60 mol% to 85 mol% is used. desirable. An ethylene unit content of 50 mol% or more is preferable because the rigidity of the entire film can be maintained satisfactorily. On the other hand, if the ethylene unit content is 95 mol% or less, the waist (rigidity at room temperature) and heat resistance of the entire film are not significantly lowered, which is practically preferable.

  The melt flow rate (MFR) of the ethylene-vinyl acetate copolymer is not particularly limited, but usually MFR (JIS K7210, temperature: 190 ° C., load: 21.18 N) is 0.5 g / It is preferably 10 minutes or more and 15 g / 10 minutes or less, and more preferably 1.0 g / 10 minutes or more and 10 g / 10 minutes or less. The MFR of the ethylene-vinyl acetate copolymer is preferably selected to have a viscosity close to that of the polylactic acid resin in order to obtain a film having a uniform thickness.

  The method for producing the resin (A) is not particularly limited. For example, a known polymerization method using a known olefin polymerization catalyst, for example, a multisite catalyst represented by a Ziegler-Natta type catalyst or a metallocene-based catalyst. Examples thereof include a slurry polymerization method, a solution polymerization method, a bulk polymerization method, and a gas phase polymerization method using a single site catalyst typified by a catalyst, and a bulk polymerization method using a radical initiator.

  In the present invention, the polyolefin resin is, for example, a polyethylene resin having the trade names “Novatech HD, LD, LL”, “Kernel”, “Toughmer A, P” (manufactured by Japan Polyethylene Corporation), “Cryolex” (manufactured by Asahi Kasei Chemicals Corporation). ), “Esplen SPO”, “Excellen VL” (manufactured by Sumitomo Chemical Co., Ltd.), “Engege” (manufactured by Dow Chemical Co., Ltd.), etc., can be used. Examples of the polypropylene resin include trade names “Novatech PP” “WINTEC” (manufactured by Nippon Polypro), “Versify” “Notio” “Toughmer XR” (manufactured by Mitsui Chemicals), “Zeras” “Thermolan” ( Commercially available products such as “Mitsubishi Chemical Co., Ltd.”, “Sumitomo Noblen” “Tough Selenium” (manufactured by Sumitomo Chemical Co., Ltd.), “IDEMITSU TPO” (manufactured by Idemitsu Kosan Co., Ltd.), “Adflex” “Adsyl” (manufactured by Sun Aroma) it can. As the ethylene vinyl acetate copolymer, commercially available products such as “Evaflex” (Mitsui / DuPont Polychemical Co., Ltd.), “Novatech EVA” (Nihon Polyethylene Co., Ltd.) can be used.

  In the present invention, the polyolefin resin (A) may further contain hydrocarbon resins. When hydrocarbon resins are included in polyolefin resins, crystallization of polyolefin resins (for example, polyethylene resins and polypropylene resins) is suppressed to improve film transparency and stretchability at low temperatures. In the case where it is configured as a heat-shrinkable film, improvement in heat-shrinkage characteristics can be expected.

In the present invention, hydrocarbon resins refer to petroleum resins, terpene resins, rosin resins, and the like. The petroleum resins can be exemplified by aromatic petroleum resins from alicyclic petroleum resins and C ₉ components from cyclopentadiene or dimer thereof. Examples of the terpene resin include terpene resins derived from β-pinene and terpene-phenol resins. Examples of rosin resins include rosin resins such as gum rosin and wood rosin, and esterified rosin resins modified with glycerin, pentaerythritol, and the like. Hydrocarbon resins are known to exhibit relatively good compatibility when mixed with polyolefin resins, etc., but it is preferable to use a hydrogenated derivative from the viewpoint of color tone, thermal stability, and compatibility. Particularly preferred are hydrogenated petroleum resins and partially hydrogenated petroleum resins.

  Some of the hydrocarbon resins have various softening temperatures depending on the molecular weight. In the present invention, those having a softening temperature of 100 ° C. or higher, preferably 110 ° C. or higher, and 150 ° C. or lower, preferably 140 ° C. or lower are suitably used. When the softening temperature is 100 ° C. or higher, it is practically preferable because it does not bleed to the surface of the sheet when mixed, causing blocking, or lowering the mechanical strength of the entire sheet and being easily broken. On the other hand, if the softening temperature is 150 ° C. or lower, the compatibility with the polyolefin-based resin is favorably maintained, and it is preferable that the film does not bleed on the surface of the film with time and blocking or transparency is not lowered.

  The content of the hydrocarbon resins is preferably 5% by mass or more, more preferably 8% by mass or more, and further preferably 10% by mass or more, based on the total amount of the polyolefin-based resin (A) (100% by mass). And, Preferably it is 50 mass% or less, More preferably, it is 40 mass% or less, More preferably, it is 30 mass% or less. Here, when the content of the hydrocarbon resins is 5% by mass or more, when the film is configured as a film transparency or heat-shrinkable film, the effect of improving the shrinkage property is remarkable, and 50% by mass or less. If this is the case, it is preferable because problems such as bleed to the surface over time and the films tend to block each other and impact resistance is reduced are unlikely to occur.

  Examples of the hydrocarbon resins include, for example, trade names “HIRAYS” (manufactured by Mitsui Chemicals), “Petrogin” (manufactured by Mitsui Chemicals), “Arcon” (manufactured by Arakawa Chemical Industries), and “Clearon” (manufactured by Yasuhara Chemical Co., Ltd.). ), “Imabe” (manufactured by Idemitsu Petrochemical Co., Ltd.), “Escollet” (manufactured by Tonex Co., Ltd.) and the like can be used.

<Polylactic acid resin (B)>
Next, the polylactic acid resin used as the resin (B) will be described. The polylactic acid resin in the present invention is a homopolymer of D-lactic acid or L-lactic acid or a copolymer thereof, and a mixture thereof is also included. More specifically, poly (D-lactic acid) whose structural unit is D-lactic acid, poly (L-lactic acid) whose structural unit is L-lactic acid, and a copolymer of L-lactic acid and D-lactic acid. Poly (DL-lactic acid), or a mixture thereof.

  When the polylactic acid resin used in the present invention is a mixture of D-lactic acid and L-lactic acid, the mixing ratio of D-lactic acid and L-lactic acid is D-lactic acid: L-lactic acid = 99.8: 0. 2 to 75:25 or D-lactic acid: L-lactic acid = 0.2: 99.8 to 25:75, preferably D-lactic acid: L-lactic acid = 99.5: 0.5 Or more preferably 80:20 or D-lactic acid: L-lactic acid = 0.5: 99.5 to 20:80. Polylactic acid composed of D-lactic acid alone or L-lactic acid alone exhibits very high crystallinity, has a high melting point, and tends to have excellent heat resistance and mechanical properties. However, when used as a heat-shrinkable film, it usually involves printing and a bag-making process using a solvent, so that the crystallinity of the constituent material itself can be lowered appropriately in order to improve printability and solvent sealability. Necessary. Moreover, when crystallinity is too high, orientation crystallization advances at the time of extending | stretching, and there exists a tendency for shrinkage | contraction characteristic to fall. From these facts, when the film of the present invention is constituted as a heat shrinkable film, the polylactic acid resin used is D-lactic acid: L-lactic acid = 99: 1 to 85:15, or D-lactic acid: L- More preferably, the lactic acid ratio is 1:99 to 15:85.

  In the present invention, the polylactic acid resin can be used by mixing copolymers of D-lactic acid and L-lactic acid having different copolymerization ratios. In that case, what is necessary is just to adjust so that the value which averaged the copolymerization ratio of D-lactic acid of a some lactic acid-type polymer and L-lactic acid may enter into the said range. Mixing two or more polylactic acid resins with different copolymer ratios of D-lactic acid and L-lactic acid according to the intended use, and adjusting the crystallinity to balance heat resistance and heat shrinkage characteristics be able to.

  The polylactic acid resin used in the present invention may be a copolymer of lactic acid and α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid. Here, the “α-hydroxycarboxylic acid” copolymerized with the lactic acid-based resin includes optical isomers of lactic acid (D-lactic acid for L-lactic acid and L-lactic acid for D-lactic acid, respectively). Glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methylbutyric acid, Bifunctional aliphatic hydroxy-carboxylic acids such as 2-hydroxycaprolactone acid, and lactones such as caprolactone, butyllactone, valerolactone and the like. Examples of the “aliphatic diol” copolymerized with the lactic acid-based resin include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like. Examples of the “aliphatic dicarboxylic acid” to be copolymerized include succinic acid, adipic acid, suberic acid, sebacic acid and dodecanedioic acid. The copolymerization ratio of the copolymer of lactic acid and α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid is lactic acid: α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid = 90: 10 to The range is preferably 10:90, more preferably 80:20 to 20:80, and still more preferably 30:70 to 70:30. If the copolymerization ratio is within the above range, a film having a good balance of physical properties such as rigidity, transparency and impact resistance can be obtained.

  The polylactic acid resin can be prepared by a known polymerization method such as a condensation polymerization method or a ring-opening polymerization method. For example, in the case of a condensation polymerization method, a polylactic acid resin having an arbitrary composition can be obtained by directly dehydrating condensation polymerization of D-lactic acid, L-lactic acid, or a mixture thereof. Further, in the ring-opening polymerization method, a lactide which is a cyclic dimer of lactic acid is subjected to ring-opening polymerization in the presence of a predetermined catalyst while using a polymerization regulator or the like, if necessary. A lactic acid resin can be obtained. The lactide includes DL-lactide, which is a racemic mixture of L-lactic acid and D-lactic acid, and these are mixed as necessary to polymerize to give a polylactic acid resin having an arbitrary composition and crystallinity. Can be obtained. Furthermore, a small amount of chain extender such as a diisocyanate compound, diepoxy compound, acid anhydride, acid chloride, etc. may be used for the purpose of increasing the molecular weight.

  The weight (mass) average molecular weight of the polylactic acid-based resin is preferably 20,000 or more, more preferably 40,000 or more, still more preferably 60,000 or more, and preferably 400,000 or less. Is 350,000 or less, more preferably 300,000 or less. When the weight (mass) average molecular weight is 20,000 or more, an appropriate resin cohesive force can be obtained, and the film can be prevented from being insufficiently stretched or embrittled. On the other hand, if the weight (mass) average molecular weight is 400,000 or less, the melt viscosity can be lowered, which is preferable from the viewpoint of production and productivity improvement.

  As a commercial item of the said polylactic acid-type resin, "NatureWorks" (made by NatureWorks LLC), "LACEA" (made by Mitsui Chemicals), etc. are mentioned, for example.

  In the present invention, the content of the polylactic acid resin (B) is preferably 1 part by mass or more, more preferably 5 parts by mass or more, with respect to 100 parts by mass of the polyolefin resin (A). More preferably, it is 10 parts by mass or more, and preferably 50 parts by mass or less, more preferably 40 parts by mass or less. By setting the content of the polylactic acid resin (B) to 50 parts by mass or less, a film having excellent impact resistance and transparency can be obtained. On the other hand, by including 1 part by mass or more of the polylactic acid-based resin (B), it can be made into a film with little environmental load, and when configured as a heat shrinkable film, it has excellent heat shrink characteristics, and A film with suppressed natural shrinkage can be obtained.

<Acrylic resin (C)>
Next, the acrylic resin (C) will be described. The acrylic resin used in the present invention is a methyl methacrylate homopolymer or a copolymer of methyl methacrylate and another vinyl monomer. Examples of the vinyl monomer include methacrylic acid esters such as ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylic acid-2-ethylhexyl, and methacrylic acid-2-hydroxyethyl; Acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate; methacrylic acid, acrylic acid Unsaturated acids such as styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, maleic anhydride, phenylmaleimide, cyclohexylmaleimide and the like.
The copolymer may further contain an elastomer component such as polybutadiene, butadiene / butyl acrylate copolymer, polybutyl acrylate copolymer, glutaric anhydride unit, or glutarimide unit. Among them, from the viewpoint of rigidity and moldability, polymethyl methacrylate resin (PMMA), which is a homopolymer of methyl methacrylate, or methyl methacrylate and ethyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate A copolymer with one or more other vinyl monomers selected from butyl acrylate, acrylic acid and methacrylic acid is preferably used. When using a copolymer of methyl methacrylate and at least one selected from ethyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid, methacrylic acid as an acrylic resin, The methyl methacrylate unit is preferably 30% by mass or more, more preferably 40% by mass, and still more preferably 50% by mass or more. By setting the methyl methacrylate unit to 30% by mass or more, it is preferable because the rigidity of the acrylic resin can be maintained and a film having excellent rigidity can be obtained. Moreover, the acrylic resin may further contain other monomer units as a copolymerization component as long as the object of the present invention is not impaired.

  The acrylic resin (C) may contain acrylic elastic particles. The acrylic elastic particles are particles made of an acrylic polymer and having rubber elasticity. The acrylic elastic particles may be a single layer or a multilayer structure acrylic polymer including a rubber elastic layer. A multilayer structure acrylic polymer including a rubber elastic layer is preferably used in that it becomes an acrylic resin film excellent in transparency. The multilayer structure acrylic polymer is an acrylic polymer having a multilayer structure of at least two layers, preferably three layers. For example, the inner layer is an alkyl acrylate ester having an alkyl group having 4 to 8 carbon atoms and polyfunctional. Examples thereof include a rubber elastic body made of a copolymer with a monomer, and a two-layer acrylic polymer whose outer layer is a hard polymer whose main component is methyl methacrylate. Among them, the innermost layer is a hard polymer whose main component is methyl methacrylate, and the intermediate layer is a rubber made of a copolymer of an alkyl acrylate having an alkyl group having 4 to 8 carbon atoms and a polyfunctional monomer. A three-layer acrylic polymer which is an elastic body and whose outermost layer is a hard polymer whose main component is methyl methacrylate is preferable. Such a multilayer structure acrylic polymer can be produced, for example, by the method described in Japanese Patent Publication No. 55-27576.

  The acrylic elastic particles are preferably 100 parts by mass or less, more preferably 60 parts by mass or less, with respect to 100 parts by mass of the acrylic resin (C) serving as a matrix. It is preferable to set the acrylic elastic particles to 100 parts by mass or less because the rigidity and transparency of the film can be maintained.

  The Vicat softening point of the acrylic resin (C) measured by JIS K7206 is preferably 100 ° C. or lower, more preferably 80 ° C. or lower, and further preferably 60 ° C. or lower. Vicat softening point of 100 ° C or less suppresses the generation of voids at the interface with the polyolefin resin (A) when the mixed resin consisting of the resins (A), (B), and (C) is stretched It is possible to maintain the transparency of the film, which is preferable.

  The weight (mass) average molecular weight of the acrylic resin (C) used in the present invention is 20,000 or more, preferably 40,000 or more, more preferably 60,000 or more, and 400,000 or less, preferably Is 350,000 or less, more preferably 300,000 or less. When the weight (mass) average molecular weight is 20,000 or more, it is possible to prevent the film from being insufficiently stretched or embrittled. On the other hand, if the weight (mass) average molecular weight is 400,000 or less, the melt viscosity can be lowered, which is preferable from the viewpoint of production and productivity improvement.

  Commercially available products of the acrylic resin (C) include, for example, “SUMIPEX” (manufactured by Sumitomo Chemical Co., Ltd.), “ACRYPET” (manufactured by Mitsubishi Rayon Co., Ltd.), “Parapet” (manufactured by Kuraray Co., Ltd.), “Artuglass” (Atofina) -Made by Japan), "Delpet" (made by Asahi Kasei) and the like.

  In the present invention, the content of the acrylic resin (C) is preferably 1 part by mass or more and 50 parts by mass or less of the acrylic resin (C) with respect to 100 parts by mass of the polyolefin resin (A). Is 5 to 40 parts by mass, more preferably 10 to 40 parts by mass. By setting the content of the acrylic resin (C) to 50 parts by mass or less, a heat-shrinkable film having excellent heat-shrinkability when configured as a film having excellent impact resistance and a heat-shrinkable film is obtained. be able to. On the other hand, by including 1 part by mass or more of the acrylic resin (C), it is possible to obtain a film having improved transparency and reduced natural shrinkage.

  In the present invention, in order to improve the dispersibility of the polyolefin-based resin (A), the polylactic acid-based resin (B), and the acrylic-based resin (C), and to obtain a film having more excellent transparency and mechanical properties, the compatibilization is performed. An agent can also be added. The compatibilizer is not particularly limited as long as it improves the dispersibility of the polyolefin resin (A), the polylactic acid resin (B), and the acrylic resin (C). Preferred compatibilizers are ethylene and vinyl acetate, acrylic acid, (meth) acrylic acid, ethyl (meth) acrylate, methyl (meth) acrylic acid, maleic anhydride, and glycidyl (meth) acrylate. Copolymers with at least one selected from the group consisting of, for example, maleic anhydride-modified SEBS, maleic anhydride-modified SEPS, epoxy-modified SEBS, epoxy-modified SEPS, etc., modified styrene resins, unsaturated carboxylic acids Or the modified olefin resin modified | denatured with the anhydride etc. is mentioned. The compatibilizer may be used alone or in combination of two or more.

  Commercially available products of the above-mentioned compatibilizer include, for example, “bond first”, “bondine”, “Aclift” (manufactured by Sumitomo Chemical Co., Ltd.), “Elvalloy” (manufactured by Mitsui DuPont Polychemical Co., Ltd.), and modified styrene. "Epofriend" (manufactured by Daicel Chemical), "Tuftec M" (manufactured by Asahi Kasei Chemicals), "Reseda" (manufactured by Nippon Gosei Co., Ltd.), "Admer" (manufactured by Mitsui Chemicals) as modified polyolefin resin, etc. Is mentioned.

  The mixing amount of the compatibilizer is preferably 1 part by mass or more, more preferably 100 parts by mass of the mixed resin composed of the polyolefin resin (A), the polylactic acid resin (B), and the acrylic resin (C). 2 parts by mass or more, more preferably 3 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and further preferably 20 parts by mass or less. When the mixing amount of the compatibilizer is 1 part by mass or more with respect to 100 parts by mass of the mixed resin, excellent transparency and impact resistance can be imparted to the film. On the other hand, the rigidity of a film is maintainable by making content of a compatibilizing agent into 30 mass parts or less.

  The film of the present invention has the polyolefin resin (A) as a main component, a polylactic acid resin (B) and a layer containing an acrylic resin (C) as intermediate layers, and a polylactic acid resin (B ) May be provided as a main component. By providing the front and back layers containing the polylactic acid resin (B) as a main component, a film with better transparency can be obtained.

  When the front and back layers are provided, other rubber components other than the polylactic acid resin can be added to the front and back layers for the purpose of improving the impact resistance of the film. Although this rubber component is not particularly limited, aliphatic polyesters other than polylactic acid resins, aromatic-aliphatic polyesters, copolymers of diols, dicarboxylic acids and lactic acid resins, and core-shell structure rubbers are suitable. Can be used for

  The film of the present invention comprises an intermediate layer composed of a mixed resin of a polyolefin resin (A), a polylactic acid resin (B), and an acrylic resin (C), and a front and back layer mainly composed of a polylactic acid resin (B). In order to improve the adhesiveness, an adhesive layer may be further provided. The resin constituting the adhesive layer is not particularly limited as long as it is a resin capable of exhibiting adhesiveness, but the resin exemplified as the compatibilizing agent can be suitably used.

  When the front and back layers and the adhesive layer are provided on the film of the present invention, the thickness ratio of each layer can be appropriately determined in consideration of transparency and the like. For example, the thickness ratio of the front and back layers to the thickness of the entire film (total thickness ratio of the front and back layers) is preferably 10% or more, more preferably 15% or more, still more preferably 20% or more, and preferably 70%. Below, more preferably 60% or less, and still more preferably 50% or less. The adhesive layer is preferably 0.5 μm or more, more preferably 0.75 μm or more, further preferably 1 μm or more, and preferably 6 μm or less, more preferably 5 μm or less because of its function. When the thickness ratio of each layer is within the above range, a laminated film having excellent transparency can be obtained.

  The film of the present invention has a moldability, productivity and heat-shrinkable film as long as it does not significantly impair the effects of the present invention in addition to the above-described components with respect to any one layer or two or more layers of the respective layers of the film. Recycled resin generated from trimming loss such as film ears, inorganic particles such as silica, talc, kaolin and calcium carbonate, pigments such as titanium oxide and carbon black, flame retardants, etc. Additives such as a weather resistance stabilizer, a heat resistance stabilizer, an antistatic agent, a melt viscosity improver, a crosslinking agent, a lubricant, a nucleating agent, a plasticizer, and an antiaging agent can be added as appropriate.

  In applications where transparency is required, the transparency of the film of the present invention is, for example, when a film having a thickness of 200 μm is measured according to JIS K7105, the haze value is preferably 20% or less, and 15% or less. More preferably, it is more preferably 10% or less. If the haze value is 20% or less, it can be used in applications requiring transparency.

<Film production method / use>
The film of the present invention includes an unstretched film, a stretched film, and a heat-shrinkable film. These films can be produced by a known method. The form of the film may be either a flat shape or a tube shape, but a flat shape is preferable in terms of productivity. A method of cutting a film produced by a tubular method into a flat shape can also be applied. By making it flat, several products can be taken in the width direction of the original film. As a method for producing a flat film, for example, for an unstretched film, a resin is melted using a plurality of extruders, co-extruded from a T die, cooled and solidified with a chilled roll, and then printed. Examples of the method include a method of obtaining a roll-shaped unstretched film by performing corona discharge treatment on the surface and then winding it with a winder. The stretched film melts the resin using a plurality of extruders, co-extrudes from a T-die, cools and solidifies with a chilled roll, stretches in the machine direction and / or transverse direction, and anneals to promote crystallization of the resin. When printing is performed, a method of obtaining a roll-shaped stretched film by performing corona discharge treatment on the surface and then winding it with a winder can be exemplified. A method for producing the heat-shrinkable film will be described later.

  The film of the present invention is used as a heat-shrinkable film, which will be described later, as an unstretched film, for food packaging, agriculture, horticulture, architectural civil engineering, etc., and as a stretched film for PET bottles It can be used for applications such as labels, shrink tubes, food packaging, and agriculture.

[Heat shrinkable film]
The heat-shrinkable film of the present invention is the film of the present invention described above having heat-shrinkability. The heat shrinkability can be imparted, for example, by stretching in a predetermined temperature range and then cooling while regulating crystallization.

  The heat-shrinkable film of the present invention has a layer composed of a mixed resin of the polyolefin resin (A), the polylactic acid resin (B), and the acrylic resin (C) as an intermediate layer, similar to the film of the present invention. Front and back layers mainly composed of the polylactic acid resin (B) can be provided on both sides thereof. By providing the front and back layers mainly composed of the polylactic acid-based resin (B), it is possible to obtain a heat-shrinkable film with better transparency and heat-shrinkage characteristics and with reduced natural shrinkage. In that case, the thickness ratio of each layer can be in the same range as the film. If the thickness ratio of each layer is within the above range, the heat-shrinkable laminate is particularly suitable for applications such as shrink-wrapping, shrink-bound wrapping, and shrink-labeling with excellent heat-shrinkability and transparency and with reduced natural shrinkage. A film can be obtained with good balance.

  In addition, when the front and back layers are provided, as in the case of the film, a polylactic acid-based resin is used for the front and back layers for the purpose of improving the impact resistance of the film within a range that does not impair the shrinkage characteristics and the rigidity (back strength) of the film. Other rubber components other than the above can also be added. Moreover, it adheres between the intermediate layer which consists of mixed resin of polyolefin resin (A), polylactic acid resin (B), and acrylic resin (C), and the front and back layers which have polylactic acid resin (B) as a main component. In order to improve the property, an adhesive layer can be provided with the same material and thickness as the film.

  The heat-shrinkable film of the present invention is the same as the above-mentioned film, with respect to any one layer or two or more layers, in addition to the above-described components, within a range not significantly impairing the effects of the present invention, moldability, production Recycled resin generated from trimming loss such as film ears, inorganic particles such as silica, talc, kaolin, calcium carbonate, titanium oxide, carbon black, etc. Additives such as pigments, flame retardants, weather resistance stabilizers, heat resistance stabilizers, antistatic agents, melt viscosity improvers, cross-linking agents, lubricants, nucleating agents, plasticizers and anti-aging agents can be appropriately added.

<Physical and mechanical properties>
The heat shrinkable film of the present invention preferably has a heat shrinkage rate of 20% or more in at least one direction when immersed in 80 ° C. warm water for 10 seconds.

  This is an index for determining the adaptability to the shrinking process in a relatively short time (several seconds to about several tens of seconds) such as the use of shrinkage labels for PET bottles. For example, the shrinkage rate required for a heat-shrinkable film applied to the use of shrinkage labels for PET bottles varies depending on the shape, but is generally about 20% to 70%.

  Further, the shrinkage processing machine that is most widely used industrially for labeling of PET bottles is generally called a steam shrinker that uses steam as a heating medium for shrinking. The heat-shrinkable film needs to sufficiently heat-shrink at a temperature as low as possible from the viewpoint of the influence of heat on the object to be coated. Furthermore, with the recent increase in the speed of the labeling process, there has been an increasing demand for shrinking quickly at a lower temperature. In consideration of such industrial productivity, a film having a heat shrinkage rate of 20% or more under the above conditions is preferable because it can sufficiently adhere to the object to be coated within the shrinkage processing time. From these facts, the heat shrinkage rate when immersed in warm water at 80 ° C. for 10 seconds is preferably at least 20%, more preferably 30%, and even more preferably the lower limit in at least one direction, usually the main shrinkage direction. The upper limit is preferably 85% or less, more preferably 80% or less, and still more preferably 75% or less.

  The “main shrinkage direction” means a direction having a large thermal shrinkage rate in the longitudinal direction (longitudinal direction) and the transverse direction (width direction). For example, in the case of mounting on a bottle, it corresponds to the outer circumferential direction. It means a direction, and “orthogonal direction” means a direction orthogonal to the main contraction direction. In the examples of the present specification, the take-up (flow) direction of the laminated film and the direction perpendicular thereto are the same as the “orthogonal direction” and the “main contraction direction”, respectively.

  In the heat-shrinkable film of the present invention, in order to adjust the heat shrinkage rate when immersed in warm water at 80 ° C. for 10 seconds to the above range, the resin composition is adjusted as described above, and the stretching temperature is adjusted. Is preferably adjusted to a range described later. For example, when it is desired to further increase the heat shrinkage rate, the polyolefin resin (A) is increased by increasing the composition ratio of the polylactic acid resin (B) constituting the film, increasing the draw ratio, lowering the stretching temperature. Means such as providing front and back layers as main components may be used.

  Further, the natural shrinkage ratio of the heat-shrinkable film of the present invention is desirably as small as possible, and the natural shrinkage ratio when stored for 7 days in an environment of 40 ° C. and 50% RH is preferably less than 10%, more preferably. Is 8% or less, more preferably 6% or less, and most preferably less than 3%. If the natural shrinkage rate under the above conditions is less than 10%, even if the produced film is stored for a long period of time, it can be stably attached to a container or the like, and problems are hardly caused in practice.

  In the heat-shrinkable film of the present invention, in order to adjust the natural shrinkage ratio when stored for 7 days in an environment of 40 ° C. and 50% RH to the above range, the resin composition should be adjusted as described above. However, it is also possible to adjust the stretching temperature by adjusting the stretching temperature to a range described later or by providing front and back layers. For example, when it is desired to reduce the natural shrinkage rate, the composition ratio of the polylactic acid resin (B) constituting the heat-shrinkable film is increased, the stretching ratio is decreased, the stretching temperature is increased, and the polylactic acid resin (B It is advisable to use means such as providing front and back layers whose main component is.

  The heat-shrinkable film according to the present invention has a transparency of 40 μm thickness in applications where transparency is required, for example, in which the printed surface printed on the back surface of the heat-shrinkable film is visible from the surface. When measured according to JIS K7105, the haze value is preferably 10% or less, more preferably 7% or less, and even more preferably 5% or less. If the haze value is 10% or less, the transparency of the film can be obtained and a display effect can be obtained.

  The impact resistance of the heat-shrinkable film of the present invention is evaluated by the tensile elongation at break, and in the tensile test under the environment of 0 ° C., particularly in the label application, the elongation rate in the take-off (flow) direction (MD) of the heat-shrinkable film. However, it is preferably 100% or more, more preferably 150% or more, and still more preferably 200% or more. If the tensile elongation at break in an environment of 0 ° C. is 100% or more, it is preferable that problems such as breakage of the heat-shrinkable film during the printing / bag making process are less likely to occur. Further, even when the tension applied to the heat-shrinkable film increases as the speed of processes such as printing and bag making increases, it is preferable that the tensile breaking elongation is 100% or more, so that it is difficult to break.

  In the heat-shrinkable film of the present invention, it is preferable to configure the resin composition as described in the present invention in order to make the elongation rate in the tensile test under a 0 ° C. environment the above range, and more specific adjustment. Examples of the method include reducing the ratio of the polylactic acid resin (B) and the acrylic resin (C) constituting the heat-shrinkable film.

  The heat-shrinkable film of the present invention has a tensile modulus measured in accordance with JIS K7127 in a direction orthogonal to the main shrinkage direction of the film is 1200 MPa or more, preferably 1300 MPa, more preferably 1400 MPa or more. . Moreover, the upper limit of the tensile elasticity modulus of the heat shrinkable film used normally is about 3000 MPa, preferably about 2900 MPa, and more preferably about 2800 MPa. Here, if the tensile elastic modulus is 1200 MPa or more, the film as a whole has high waist (rigidity at room temperature), and in particular, even when the film thickness is thinned, When covering with a labeling machine or the like, it is preferable that problems such as covering at an angle or the yield being liable to decrease due to film folding or the like hardly occur. The said tensile elasticity modulus can be measured on 23 degreeC conditions according to JISK7127.

<Method for producing heat-shrinkable film>
The heat-shrinkable film of the present invention can be produced by a known method. The shape of the heat-shrinkable film may be either a flat shape or a tube shape, but it is flat in terms of productivity (a few products can be taken in the width direction of the original film) and printing on the inner surface. The shape is preferred. As a method for producing a flat heat-shrinkable film, for example, a resin is melted using a plurality of extruders, co-extruded from a T-die, cooled and solidified with a chilled roll, roll-stretched in the vertical direction, The film is then stretched, annealed, cooled under conditions that can regulate the crystallization of the resin, and if printing is applied, the surface is subjected to corona discharge treatment and wound with a winder. And a method for producing a heat-shrinkable film roll having a predetermined length (usually 1000 m or more, preferably 2000 mm or more, more preferably 3000 m or more, the same shall apply hereinafter). Moreover, the method of cutting open the film manufactured by the tubular method and making it flat is also applicable.

  The stretching ratio is preferably 2 times or more, more preferably 3 times or more, and preferably 10 times or less, more preferably 6 times or less in the longitudinal direction in applications such as overlap for shrinking in two directions. In addition, the lateral direction is preferably 2 times or more, more preferably 3 times or more, and preferably 10 times or less, more preferably 6 times or less. On the other hand, in applications such as for heat-shrinkable labels that shrink mainly in one direction, the direction corresponding to the main shrinkage direction is preferably 2 to 10 times, more preferably 4 to 8 times, and the direction orthogonal thereto. Preferably, the magnification ratio is 1 to 2 times (where 1 times refers to the case where the film is not stretched), more preferably 1.1 to 1.5 times, which is substantially in the range of uniaxial stretching. Is selected. A biaxially stretched film stretched at a stretch ratio within the above range does not have an excessively large thermal shrinkage rate in the direction orthogonal to the main shrinkage direction.For example, when used as a shrinkage label, It is preferable because the so-called vertical shrinkage phenomenon, in which the film is thermally contracted in the vertical direction, can be suppressed.

  The stretching temperature needs to be changed depending on the glass transition temperature of the resin used and the properties required for the heat-shrinkable film, but is generally 50 ° C. or higher, preferably 60 ° C. or higher, and the upper limit is 130 ° C. or lower, preferably 110 ° C. It is controlled within the following range. Next, the stretched film is subjected to a heat treatment or relaxation treatment at a temperature of about 50 ° C. or more and 100 ° C. or less for the purpose of reducing the natural shrinkage rate or improving the heat shrink property, if necessary. It cools rapidly within the time not to relax, and becomes a heat-shrinkable film.

  The heat-shrinkable film of the present invention is subjected to surface treatment and surface treatment such as corona treatment, printing, coating and vapor deposition, and bag making and perforation treatment with various solvents and heat seals as necessary. Can do.

  The heat-shrinkable film of the present invention is processed from a flat shape to a cylindrical shape or the like by an article to be packaged and provided for packaging. When printing is required in a cylindrical container such as a plastic bottle, first print the required image on one side of a wide flat film wound up on a roll, and then cut it to the required width while the print side is inside. The center seal (the shape of the seal portion is a so-called envelope) may be folded into a cylindrical shape. As the center sealing method, an organic solvent bonding method, a heat sealing method, an adhesive method, and an impulse sealer method can be considered. Among these, from the viewpoint of productivity and appearance, an adhesion method using an organic solvent is preferably used.

[Molded products, heat-shrinkable labels and containers]
The heat-shrinkable film of the present invention is excellent in low-temperature shrinkage, shrinkage finish, transparency, natural shrinkage, etc. of the film, and its use is not particularly limited. By forming a vapor deposition layer and other functional layers, it can be used as various molded products such as bottles (blow bottles), trays, lunch boxes, prepared food containers, and dairy products containers. In particular, when the heat-shrinkable film of the present invention is used as a heat-shrinkable label for food containers (eg, PET bottles, glass bottles, preferably PET bottles for soft drinks or foods), a complicated shape (eg, a narrow center) Even if it is a cylinder, a square column with a corner, a pentagonal column, a hexagonal column, etc., it can adhere to the shape, and a container with a beautiful label without wrinkles or avatars can be obtained. The molded article and container of the present invention can be produced by using a normal molding method.

  Since the heat-shrinkable film of the present invention has excellent shrinkage properties and shrinkage finishing properties, in addition to the heat-shrinkable label material of a plastic molded product that is deformed when heated to a high temperature, it has a coefficient of thermal expansion and water absorption. Materials very different from the heat-shrinkable film of the present invention, for example, polyolefin resin such as metal, porcelain, glass, paper, polyethylene, polypropylene, polybutene, polymethacrylate resin, polycarbonate resin, polyethylene terephthalate, polybutylene terephthalate It can utilize suitably as a heat-shrinkable label raw material of the package (container) which used at least 1 sort (s) chosen from polyester-type resins, such as such as a constituent material.

  Examples of the material constituting the plastic package in which the heat-shrinkable film of the present invention can be used include polystyrene, rubber-modified impact-resistant polystyrene (HIPS), and styrene-butyl acrylate, in addition to the resin described in the above section “Film”. Copolymer, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), (meth) acrylic acid-butadiene-styrene copolymer (MBS), polychlorinated Examples thereof include vinyl resins, phenol resins, urea resins, melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. These plastic packages may be a mixture of two or more resins or a laminate.

  Hereinafter, the present invention will be described in detail with reference to examples. In the examples, the film take-up (flow) direction is described as MD, and the perpendicular direction thereof as TD.

The raw materials used in the following examples and comparative examples are as follows.
<Olefin resin (A)>
A-1: PP Wintec WFX6 (MFR3.0, Tm132 ° C.) manufactured by Nippon Polypro Co., Ltd.
A-2: Ube Industries, Ltd. LLDPE UMERI T0540F (MFR4.0, Tm103 ° C.)
A-3: Hydrogenated petroleum resin Arakawa Chemical Co., Ltd. Alcon P140 (softening point 90 ° C)
A-4: Nippon Polyethylene EVA Novatec EVA LV430 (MFR1.0, Tm: 89 ° C.)

<Polylactic acid resin (B)>
B-1: Polylactic acid NatureWorks 4060D manufactured by NatureWorks LLC
B-2: Soft polylactic acid resin Puramate PD150 manufactured by Dainippon Ink & Chemicals, Inc.
B-3: Polylactic acid NatureWorks 4050D manufactured by NatureWorks LLC

<Acrylic resin (C)>
C-1: Sumitomo Chemical Co., Ltd. acrylic Sumipex LG21 (copolymer of methyl methacrylate and methyl acrylate)
C-2: Soft acrylic Sumipex FA (copolymer of methyl methacrylate and butyl acrylate) manufactured by Sumitomo Chemical Co., Ltd.
C-3: Kuraray acrylic parapet GR H24 (copolymer of methyl methacrylate and butyl acrylate)

<Compatibilizer>
D-1: Acid-modified SEBS Tuftec M1913 manufactured by Asahi Kasei Chemicals
D-2: Et-GMA copolymer Bond First 7M manufactured by Sumitomo Chemical Co., Ltd.

<Adhesive layer resin>
E-1: Modified PO Admer SE800 manufactured by Mitsui Chemicals, Inc.
E-2: EMA Elvalloy AC1242 manufactured by Mitsui DuPont Polychemical Co., Ltd.

  Furthermore, the measurement and evaluation described below were performed for the films obtained in each of the examples and comparative examples. However, for the unstretched film, only a haze value was evaluated in accordance with JIS K7105 for a film having a film thickness of 150 μm.

(1) Heat Shrinkage The film was cut into a size of MD 100 mm and TD 100 mm from the obtained heat-shrinkable film roll, immersed in a hot water bath at 80 ° C. for 10 seconds, and the amount of shrinkage was measured. As for the thermal shrinkage rate, the ratio of shrinkage to the original size before shrinkage was expressed as a% value for MD and TD.

(2) Natural shrinkage rate The film was cut into a size of MD 100 mm and TD 1000 mm from the obtained heat-shrinkable film roll, and left in a constant temperature bath in an atmosphere of 40 ° C. and 50% RH for 7 days, about the main shrinkage direction (TD) The amount of shrinkage relative to the original size before shrinkage was measured, the ratio was calculated as a% value, and evaluated according to the following criteria.
◎: When the natural shrinkage rate is 6.0% or less ○: When the natural shrinkage rate is over 6.0% and 10.0% or less ×: When the natural shrinkage rate is over 10.0%

(3) Haze value The haze value of a film having a thickness of 40 μm was measured according to JIS K7105. The measurement results were evaluated according to the following criteria.
◎: Haze value is less than 5% ○: Haze value is 5% or more and less than 10% ×: Haze value is 10% or more

(4) Tensile Breaking Elongation According to JIS K7127, tensile breaking elongation was measured in the direction (MD) perpendicular to the main shrinkage direction of the film under the conditions of No. 1 type test piece, temperature 0 ° C., test speed 100 mm / min. . The measurement results were evaluated according to the following criteria.
A: Tensile breaking elongation is 200% or more B: Tensile breaking elongation is 100% or more and less than 200% X: Tensile breaking elongation is less than 100%

(5) Shrinkage finish The film which printed the grid of the 10 mm space | interval was cut out to the magnitude | size of MD100mmxTD298mm, the both ends of TD were piled up 10mm, and it heat-sealed with the heat seal machine, and produced the cylindrical film. This cylindrical film was attached to a cylindrical PET bottle having a capacity of 1.5 L, and passed through the shrinking tunnel having a length of 3.2 m (3 zones) of the steam heating system in about 8 seconds. The atmospheric temperature in the tunnel in each zone was set to a range of 75 to 95 ° C. by adjusting the amount of steam with a steam valve. After film coating, the following criteria were evaluated.
A: Shrinkage is sufficient, and the attached label has a tight feeling.
○: Shrinkage is sufficient, but the attached label is not tight.
X: Shrinkage is insufficient and the attached label is loose.

  The film was evaluated as (◎) for a film in which all of the above five evaluation items were ◎, (○) for a film containing ○, and (×) for a film having at least one x.

<Examples 1-4, Comparative Examples 1 and 2>
The polyolefin resin, polylactic acid resin, acrylic resin, and other resins and additives shown in Table 1 are put into a twin-screw extruder manufactured by Toshiba Machine Co., Ltd., melt mixed at a set temperature of 200 ° C., and then a single layer Alternatively, it was extruded from a laminated T die, taken up with a cast roll at 50 ° C., and cooled and solidified to obtain an unstretched sheet having a width of 300 mm and a thickness of 150 μm. The laminated film of Example 3 is a back layer (40 μm) / core layer (70 μm) / surface layer (40 μm), and the laminated film of Example 4 is a back layer (40 μm) / adhesive layer (10 μm) / core layer ( 50 μm) / adhesive layer (10 μm) / surface layer (40 μm).

  When the haze value of the obtained unstretched sheet was measured, the results shown in Table 2 were obtained. As a result, it was confirmed that the unstretched sheets (Examples 1 to 4) defined by the present invention can obtain good haze values when compared with the sheets of Comparative Examples 1 and 2.

<Examples 5 to 10, Comparative Examples 3 and 4, Reference Examples 1 and 2>
The polyolefin resin, polylactic acid resin, acrylic resin, and other resins and additives shown in Table 3 are put into a twin-screw extruder manufactured by Toshiba Machine Co., Ltd. The sheet was extruded from a laminated T die, taken up with a cast roll at 50 ° C., and cooled and solidified to obtain an unstretched sheet having a width of 300 mm and a thickness of 200 μm. This unstretched sheet was stretched 5.0 times in the transverse uniaxial direction at a preheating temperature of 80 ° C. and a stretching temperature of 73 ° C. by a film tenter manufactured by Kyoto Machine Co., Ltd., and then heat treated at 80 ° C. Got. Subsequently, after slitting and removing the edge part of the obtained heat-shrinkable film, this film was wound up by 1000 m. The thickness of the obtained heat-shrinkable film was 40 μm.

  Each layer thickness of the unstretched sheet of Example 8 is back layer (50 μm) / core layer (100 μm) / surface layer (50 μm), and each layer thickness of the unstretched sheets of Examples 9 and 10 is back layer (50 μm). / Adhesive layer (10 μm) / core layer (80 μm) / adhesive layer (10 μm) / surface layer (50 μm).

  When various performances of the obtained heat-shrinkable film were measured, the results shown in Table 4 were obtained.

As shown from the results in Table 4, the heat-shrinkable films (Examples 5 to 10) defined in the present invention were excellent in the evaluation results of each performance. In particular, the heat-shrinkable film having the structure shown in Examples 9 and 10 showed a high overall performance evaluation result. On the other hand, the film of Comparative Example 3 consisting only of the resin (A) was inferior in evaluation in terms of the natural shrinkage rate and shrinkage finish.
Moreover, the film of the comparative example 4 which consists of resin (A) and (B) and does not have resin (C) had a haze value exceeding 10%, and was inferior to transparency.

  While the present invention has been described in connection with embodiments that are presently the most practical and preferred, the present invention is not limited to the embodiments disclosed herein. However, the present invention can be changed as appropriate without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and a film accompanying such a change, a heat-shrinkable film, and the like are also within the technical scope of the present invention. It must be understood as included.

  The film and heat-shrinkable film of the present invention can be used for forming molded articles such as bottles and trays, or as heat-shrinkable labels for packaging bodies such as bottles.

Claims (9)

The polyolefin resin (A) is contained as a main component, and the polylactic acid resin (B) is added in an amount of 1 part by mass to 50 parts by mass with respect to 100 parts by mass of the polyolefin resin (A), and the acrylic resin (C). Having at least one layer containing 1 part by weight or more and 50 parts by weight or less,
The acrylic resin (C) is
Methyl methacrylate homopolymer, or
A copolymer of methyl methacrylate and one or more other vinyl monomers selected from ethyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid, and methacrylic acid. A film characterized by being. The polyolefin resin (A) is any resin selected from the group consisting of a polyethylene resin, a polypropylene resin, an ethylene-vinyl acetate copolymer, and a mixed resin thereof. The film described. (Compounding agent (D) as a compatibilizer (D) with respect to 100 parts by mass of the mixed resin comprising the polyolefin resin (A), the polylactic acid resin (B), and the acrylic resin (C); 1 part by weight of a copolymer of acrylic acid; ethyl (meth) acrylate; methyl (meth) acrylic acid; maleic anhydride; and at least one selected from the group consisting of glycidyl (meth) acrylates The film according to claim 1 or 2, further comprising 30 parts by mass or less. The film according to any one of claims 1 to 3, further comprising front and back layers mainly composed of a polylactic acid resin (B). A heat shrinkable film, wherein the film according to claim 1 has heat shrinkability. 6. The heat-shrinkable film according to claim 5, wherein a shrinkage rate in at least one direction is 20% or more when immersed in warm water at 80 ° C. for 10 seconds. A molded article using the heat-shrinkable film according to claim 5 as a substrate. A heat-shrinkable label using the heat-shrinkable film according to claim 5 or 6 as a substrate. A container equipped with the molded article according to claim 7 or the heat-shrinkable label according to claim 8.