JP2016055636A - Shrink label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shrink label having a shrink film excellent in transparency while maintaining relaxation suppressing properties.SOLUTION: A shrink label of the present invention is a shrink label having a shrink film. The shrink film includes a base layer part and surface layers provided on both surfaces of the base layer part. The surface layers each contains 50 wt% or more polystyrene resin. The base layer part comprises 5-65 layers. As the layers in the base layer part, two or more layers (layers A) are included which contain a polystyrene resin and a polyolefin resin, wherein the total content of the polystyrene resin and the polyolefin resin is 50 wt% or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a shrink label. More specifically, for example, the present invention relates to a shrink label that is suitable for use in containers such as beverages, foods, toiletries, and pharmaceuticals.

  Currently, plastic bottles such as PET bottles and metal bottles such as bottle cans are widely used as containers for beverages such as tea and soft drinks. These containers are often equipped with plastic labels to give display, decoration, and functionality. For example, because of the merits of decoration, workability (followability to containers), wide display area, etc., shrink Shrink labels or the like in which a printing layer is provided on a film (heat-shrinkable film) are widely used.

  As the shrink label, there is known a shrink label having a different kind of laminated film in which different resin materials are laminated for the purpose of imparting various functions to the label. For example, as a shrink label that achieves both low specific gravity and center sealability with a solvent, a polyolefin resin layer is used as the core material, and a resin layer containing polystyrene resin as the main component is laminated on both sides via an acid-modified polyethylene resin. A label made of a heat-shrinkable label film is known (for example, see Patent Document 1). In addition to low specific gravity, as a shrink label having good printability, solvent sealability, and dimensional stability, an adhesive resin layer made of hydrogenated styrene resin is provided on both surfaces of the layer made of olefin resin, A heat-shrink label having a heat-shrinkable laminated film provided with both outer layers made of styrene resin is known (for example, see Patent Document 2).

Japanese Patent No. 3286594 JP 2002-86637 A

  A heterogeneous laminated film in which such a polyolefin resin material layer and a polystyrene resin material layer are laminated has a printability superior to that of a polyolefin film by having a polystyrene resin material layer on the film surface. And it has a high relaxation inhibitory property compared with a polyester-type film and a polystyrene-type film by having a layer of a polyolefin-type resin material. Here, relaxation deterrence means a container for carbonated beverages that shrinks and deforms when the internal pressure drops when opened, and a container for frozen contents that shrinks and deforms when the frozen contents are dissolved. When deforming a deformable container such as a tube container that dents and deforms when it is squeezed to take out the contents, the label does not follow the deformation of the container, and there is a gap between the label and the container. A property that suppresses the phenomenon that occurs.

  In recent years, from the viewpoint of environmental protection, recovered materials are often used also in shrink films. In the case where the above-described different laminated film is used as a collected raw material, it is difficult to completely separate each layer of the laminated film and collect the raw material, and therefore, the mixed resin is often used as the collected raw material as it is. However, the transparency of the film produced using the mixed resin as a recovered raw material in this way may be impaired. In particular, a mixed resin of a polyolefin resin and a polystyrene resin as described above has poor compatibility between the resins, and transparency is often impaired. Accordingly, a shrink label having a shrink film using a mixed resin of a polyolefin resin and a polystyrene resin is required to have high transparency while maintaining the effect of a hybrid of the polyolefin resin and the polystyrene resin. is the current situation.

  That is, the objective of this invention is providing the shrink label which has a shrink film excellent in transparency, maintaining relaxation deterrence.

  This invention is a shrink label which has a shrink film, Comprising: The said shrink film has a base layer part and the surface layer provided in the both surfaces side of the said base layer part, and the said surface layer is a polystyrene-type resin. The base layer part contains 5 to 65 layers, the base layer part contains a polystyrene resin and a polyolefin resin, and contains the polystyrene resin and the polyolefin resin. A shrink label comprising two or more layers (A layer) having a total amount of 50% by weight or more is provided.

  Furthermore, the present invention provides the shrink label, wherein the surface layer and the outermost layer of the base layer portion are directly laminated, and the outermost layer of the base layer portion is the A layer.

  Furthermore, the present invention provides the shrink label, wherein the base layer part contains at least one layer (B layer) containing 50% by weight or more of a polyolefin-based resin as a layer in the base layer part.

  Furthermore, the present invention provides the shrink label, wherein the base layer portion has a structure in which the A layer and the B layer are directly laminated.

  Furthermore, this invention provides the said shrink label whose thickness per said A layer is 0.2-8 micrometers.

  Since the shrink label of the present invention has the above specific configuration, it has a shrink film excellent in transparency and is excellent in relaxation deterrence. Therefore, the shrink label is used when a label is attached to a container that is easily deformed. However, the label is not easily dropped from the container, and the decorativeness is excellent. In addition, even when a container with a label is held over the label, the container is less likely to become unstable.

It is the schematic (partial sectional drawing) which shows an example of the shrink label of this invention. It is the schematic (partial sectional drawing) which shows another example of the shrink label of this invention. It is the schematic (partial sectional drawing) which shows another example of the shrink label of this invention. It is the schematic which shows an example of the cylindrical shrink label which is one Embodiment of the shrink label of this invention. FIG. 5 is a schematic diagram showing an example of a cylindrical shrink label that is an embodiment of the shrink label of the present invention (enlarged view of a main part of the A-A ′ cross section in FIG. 4).

  The shrink label of the present invention is a shrink label having a shrink film. In the present specification, the shrink film (that is, the shrink film included in the shrink label of the present invention) may be referred to as “the shrink film of the present invention”. The shrink label of this invention may contain layers other than the shrink film of this invention within the range which does not impair the effect of this invention.

[Shrink film]
The shrink film of this invention has a surface layer laminated | stacked on the both surfaces side of the base layer part. That is, the shrink film of the present invention includes a base layer portion and surface layers provided on both sides of the base layer portion. Specifically, the shrink film of the present invention has a layer structure of surface layer / base layer portion / surface layer, and preferably the base layer portion and the surface layer are directly laminated. In the shrink film of the present invention, the surface layers on both sides of the base layer portion may be the same layer, or may be different from each other within the range of the surface layer defined in the present application. Layers having different resin compositions and layer thicknesses) may be used. In the shrink film of the present invention, an antistatic layer or an anchor coat layer may be provided on the outer surface of the surface layer as long as the object of the present invention is not impaired. If necessary, the surface of the shrink film of the present invention may be subjected to conventional surface treatment such as corona discharge treatment, primer treatment, and frame treatment.

<Surface layer>
The surface layer in the shrink film of the present invention (that is, the surface layer provided on each side of the base layer portion) is a layer containing 50% by weight or more of polystyrene resin in the layer. Thereby, the shrink film of this invention has good paste of printing ink, is excellent in printability, and can make heat shrinkability high.

  The surface layer contains a polystyrene resin as an essential component. The said polystyrene-type resin may use only 1 type, and may use 2 or more types. Further, the surface layer is not particularly limited, but may contain a resin other than the polystyrene resin.

  The polystyrene resin is a polymer composed of a styrene monomer as an essential monomer component. That is, it is a polymer containing at least a structural unit derived from a styrene monomer in the molecule (in one molecule).

  Although it does not specifically limit as said styrene-type monomer, For example, styrene, alpha-methyl styrene, m-methyl styrene, p-methyl styrene, p-ethyl styrene, p-isobutyl styrene, pt-butyl styrene, Examples include chloromethylstyrene. Among these, styrene is preferable from the viewpoint of availability, material price, and the like. In addition, the said styrene-type monomer may use only 1 type, and may use 2 or more types.

  The polystyrene resin is not particularly limited. For example, a homopolymer of a styrene monomer such as general-purpose polystyrene (GPPS) that is a homopolymer of styrene; only two or more styrene monomers are used alone. Copolymer constituted as a monomer component; styrene-diene copolymer; copolymer such as styrene-polymerizable unsaturated carboxylic acid ester copolymer; polystyrene and synthetic rubber (for example, polybutadiene, polyisoprene, etc.) ), High-impact polystyrene (HIPS) such as polystyrene obtained by graft-polymerizing styrene to synthetic rubber; polymers containing styrene monomers (for example, styrene monomers and (meth) acrylic acid ester monomers) A rubber-like elastic body is dispersed in a continuous phase of a copolymer with a polymer, and the copolymer is graft-polymerized on the rubber-like elastic body. Styrene (referred graft type high impact polystyrene "graft HIPS"); and styrene elastomers. Among the polystyrene resins, styrene-diene copolymers are preferable. In addition, the said polystyrene type resin may use only 1 type, and may use 2 or more types.

  The styrene-diene copolymer is a copolymer composed of styrene monomers and dienes (particularly conjugated dienes) as essential monomer components. That is, it is a polymer containing at least a structural unit derived from a styrene monomer and a structural unit derived from a diene (particularly conjugated diene) in the molecule (in one molecule).

  The diene is not particularly limited, but is preferably a conjugated diene, such as 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, 1, Examples include 3-pentadiene, 1,3-hexadiene, chloroprene. Among these, 1,3-butadiene is particularly preferable from the viewpoints of stretching properties, heat shrinkability, and interlayer strength. In addition, the said diene may use only 1 type and may use 2 or more types.

  The monomer component constituting the styrene-diene copolymer may further contain a monomer component other than the styrene monomer and the diene. Examples of monomer components other than the styrene monomer and the diene include vinyl monomers, polymerizable unsaturated carboxylic acid esters, and polymerizable unsaturated carboxylic anhydrides.

  The form of copolymerization of the styrene-diene copolymer is not particularly limited, and examples thereof include random copolymers, block copolymers, and graft copolymers. Among these, block copolymers are preferable, and examples thereof include styrene block (S) -diene block (D) type, SDS type, DSD type, and SSD type. .

  Examples of the block copolymer of styrene-diene copolymer (styrene-diene block copolymer) include styrene-butadiene block copolymers (SBC) such as styrene-butadiene-styrene block copolymer (SBS). ), Styrene-isoprene block copolymers (SIS) and other styrene-isoprene block copolymers, styrene-butadiene-isoprene-styrene block copolymers (SBIS) and other styrene-butadiene-isoprene block copolymers, etc. Among them, a styrene-butadiene block copolymer is preferable. In addition, these block copolymers may use only 1 type and may use 2 or more types.

  The styrene-butadiene block copolymer is not particularly limited as long as it is a copolymer having a styrene block in which only a styrene monomer is polymerized and a butadiene block in which only butadiene is polymerized. Styrene-butadiene block copolymer having styrene blocks at both ends, such as butadiene-styrene block copolymer (SBS) and styrene-butadiene-styrene-butadiene-styrene block copolymer (SBSBS); (SB), a styrene-butadiene block copolymer having a styrene block and a butadiene block at each end, such as a styrene-butadiene-styrene-butadiene copolymer (SBSB); a butadiene-styrene-butadiene copolymer (BSB). , Butadiene - styrene - butadiene - styrene - butadiene block copolymer, and the like - styrene with butadiene copolymer (BSBSB) butadiene block such at both ends. Among these, a styrene-butadiene block copolymer having a styrene block at both ends is preferable, and SBS is more preferable. In addition, these styrene-butadiene block copolymers may use only 1 type, and may use 2 or more types.

  The styrene-diene block copolymer can be produced by a known or conventional method for producing a block copolymer. Examples of the method for producing the styrene-diene block copolymer include living polymerization (living radical polymerization, living anion polymerization, living cation) that can easily control the molecular weight, molecular weight distribution, terminal structure and the like of the styrene-diene block copolymer. Polymerization). The living polymerization can be carried out by a known or conventional method.

  When the polystyrene resin contained in the surface layer is a styrene-diene copolymer, the content of the structural unit derived from the styrene monomer in the styrene-diene copolymer is not particularly limited. -50 weight% or more and less than 100 weight% is preferable with respect to the total weight (100 weight%) of a diene type copolymer, More preferably, it is 70 to 95 weight%, More preferably, it is 80 to 95 weight%. When the content is 50% by weight or more, the rigidity of the shrink label is increased, and the heat shrinkability of the shrink film is improved, which is preferable.

  When the polystyrene resin contained in the surface layer is a styrene-diene copolymer, the content of the structural unit derived from diene in the styrene-diene copolymer is not particularly limited, but the styrene-diene copolymer is not limited. It is preferably more than 0% by weight and 50% by weight or less, more preferably 5 to 30% by weight, still more preferably 5 to 20% by weight, based on the total weight (100% by weight) of the polymer. In particular, it is preferable that the content of the structural unit derived from the conjugated diene in the styrene-conjugated diene copolymer satisfies the above range. When the content is 5% by weight or more, the surface layer is not too hard and the film is difficult to break during the production of the shrink film, which is preferable. Moreover, the said content is 50 weight% or less, and the heat shrinkability of a surface layer and a shrink film improves more, and is preferable.

  In addition, when the surface layer is a mixed resin layer containing two or more kinds of styrene-diene copolymers, the content of the structural unit derived from the styrene monomer and the content of the structural unit derived from the diene The amount is the content in all styrene-diene copolymers.

The content of the structural unit derived from the styrene monomer and the content of the structural unit derived from the diene are the compositions of the styrene-diene copolymer (each styrene-diene copolymer contained in each styrene-diene copolymer). The content of the structural unit and the content of each styrene-diene copolymer in all styrene-diene copolymers contained in the layer can be controlled. More specifically, for example, in the styrene-diene copolymer, the content of the structural unit derived from the styrene monomer is s ₁ (% by weight) and the content of the structural unit derived from the diene is d. ₁ (% by weight) of the styrene-diene copolymer (PS1) and the content of the structural unit derived from the styrene monomer is s ₂ (% by weight) and the content of the structural unit derived from the diene. It is a resin mixture composed only of a styrene-diene copolymer (PS2) that is d ₂ (% by weight), and the content of PS1 in 100% by weight of the above resin mixture (resin mixture of PS1 and PS2) is W ₁ (wt%), when the content of PS2 is W ₂ (wt%), the content of constituent units derived from the content and diene constituent units derived from the styrene monomer of the resin mixture The amount is generally controlled as follows Kill.
Content (% by weight) of structural unit derived from styrenic monomer = (s ₁ × W ₁ + s ₂ × W ₂ ) / 100
Content (% by weight) of structural unit derived from diene = (d ₁ × W ₁ + d ₂ × W ₂ ) / 100

  The analysis / measurement of the content of the structural unit (the structural unit derived from a styrene monomer and the structural unit derived from a diene) and the content of the structural unit is not particularly limited. For example, nuclear magnetic resonance (NMR), gas chromatograph It can be performed by a tomograph mass spectrometer (GCMS) or the like. In addition, analysis / measurement of other resin layers (layers in the base layer portion, etc.) and the constituent units in the resin and the content of the constituent units can be performed in the same manner.

  The polystyrene resin is not particularly limited, but may be hydrogenated. That is, the polystyrene resin may be a hydrogenated polystyrene resin (hydrogenated polystyrene resin). The hydrogenated polystyrene resin is not particularly limited, but hydrogenated styrene-butadiene-styrene block copolymer (SEBS) or hydrogenated styrene-isoprene-styrene block copolymer which is a resin obtained by adding hydrogen to SBS or SIS. Hydrogenated styrene-diene copolymers such as coalesced (SEPS) are preferred. The hydrogenated polystyrene resin may be used alone or in combination of two or more.

  Moreover, although the said polystyrene-type resin is not specifically limited, The polar group may be introduce | transduced. That is, the polystyrene resin may be a polystyrene resin into which a polar group has been introduced (modified polystyrene resin). The modified polystyrene resin includes a hydrogenated polystyrene resin into which a polar group has been introduced.

  The modified polystyrene resin is a polystyrene resin in which a polar group is introduced using a polystyrene resin as a main chain skeleton. The polar group is not particularly limited, and examples thereof include an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, a carboxylic acid chloride group, a carboxylic acid amide group, a carboxylic acid group, a sulfonic acid group, and a sulfonic acid ester group. Sulfonic acid chloride group, sulfonic acid amide group, sulfonic acid group, isocyanate group, epoxy group, amino group, imide group, oxazoline group, hydroxyl group and the like. Among these, an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, and an epoxy group are preferable, and a maleic anhydride group and an epoxy group are more preferable. As for the said polar group, only 1 type may be used and 2 or more types may be used.

  Although it does not specifically limit as said modified polystyrene resin, The modified body of hydrogenated styrene-butadiene-styrene block copolymer (SEBS) and the modified body of hydrogenated styrene-propylene-styrene block copolymer (SEPS) are preferable. . That is, the modified polystyrene resin is not particularly limited, but acid anhydride-modified SEBS, acid anhydride-modified SEPS, epoxy-modified SEBS, and epoxy-modified SEPS are preferable, and maleic anhydride-modified SEBS and maleic anhydride are more preferable. Modified SEPS, epoxy-modified SEBS, and epoxy-modified SEPS. Only 1 type may be used for the said modified polystyrene resin, and 2 or more types may be used for it.

  The polystyrene resin is not particularly limited, but may be a soft polystyrene resin. The soft polystyrene resin is not particularly limited as long as it can be used as a polystyrene resin that improves the adhesion between the layers in the shrink film of the present invention due to its softness. The soft polystyrene resin is not particularly limited, and examples thereof include styrene elastomers, styrene-diene copolymers, HIPS (high impact polystyrene) having a large rubber component, and graft HIPS having a large rubber component. Of these, styrene elastomers and styrene-diene copolymers are preferable. Only 1 type may be used for the said soft polystyrene resin, and 2 or more types may be used for it. The styrene elastomer may contain a diene component and may be a styrene-diene copolymer elastomer. In addition, HIPS with many said rubber components means HIPS in which content of a rubber component exceeds 30 weight% with respect to the total weight (100 weight%) of HIPS. The graft HIPS having a large amount of the rubber component refers to graft HIPS in which the content of the rubber component exceeds 30% by weight with respect to the total weight (100% by weight) of the graft HIPS.

  The soft polystyrene resin includes a hydrogenated soft polystyrene resin (hydrogenated soft polystyrene resin). The hydrogenated soft polystyrene resin is not particularly limited, but a hydrogenated styrene elastomer and a hydrogenated styrene-diene copolymer (particularly, a styrene-diene copolymer having a large amount of hydrogenated diene components). preferable.

  The styrene-diene copolymer elastomer is a styrene-diene copolymer in which the content of structural units derived from diene is 50% by weight or more based on the total weight (100% by weight) of the styrene-diene copolymer. A copolymer is preferable, More preferably, it is 60 to 95 weight%, More preferably, it is 65 to 90 weight%.

  Commercially available products may be used as the polystyrene-based resin. For example, “Clearen 530L”, “Clearen 730L” manufactured by Denki Kagaku Kogyo Co., Ltd., “Tufrene 126S”, “Asaprene T411” manufactured by Asahi Kasei Corporation, Kraton Polymer “Clayton D1102A”, “Clayton D1116A” manufactured by Japan Co., Ltd., “Styrolux S”, “Styrolux T” manufactured by Stylorusion Corporation, “Asaflex 840”, “Asaflex 860” manufactured by Asahi Kasei Chemicals Corporation Above, SBS), PS Japan Co., Ltd. “679”, “HF77”, “SGP10”, DIC Corporation “Dick Styrene XC-515”, “Dick Styrene XC-535” (above, GPPS), PS “475D”, “H0103”, “ T478 ", DIC Corporation" Dick Styrene GH-8300-5 "(above, HIPS), Asahi Kasei Chemicals Corporation" Tough Tech H Series ", Shell Japan Ltd." Clayton G Series "(above, SEBS ), "Dynalon" (hydrogenated styrene-butadiene random copolymer) manufactured by JSR Corporation, "Septon" (SEPS) manufactured by Kuraray Co., Ltd., "Tuftec M Series" manufactured by Asahi Kasei Chemicals Corporation, Daicel Corporation "Epofriend" manufactured by JSR, "polar group-modified dynalon" manufactured by JSR Corporation, "Reseda" manufactured by Toagosei Co., Ltd. (modified polystyrene resin), "Tuftec P Series" manufactured by Asahi Kasei Chemicals Corporation (hydrogenated) Styrene-based elastomer).

  The content of the polystyrene-based resin in the surface layer is 50% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more based on the total weight (100% by weight) of the surface layer. In particular, the SBS content in the surface layer preferably satisfies the above range. The upper limit of the content is not particularly limited, and may be 100% by weight. When the content is less than 50% by weight, the effect of improving high heat shrinkability and printability cannot be obtained.

  The surface layer is within the range not impairing the effects of the present invention, and includes lubricants, fillers, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, antifogging agents, flame retardants, colorants, pinning agents ( An additive such as an alkaline earth metal) or a compatibilizing agent may be contained.

<Base layer part>
The base layer part in the shrink film of the present invention includes 5 to 65 layers. In addition, the base layer portion contains a polystyrene resin and a polyolefin resin as a layer in the base layer portion, and the total content of the polystyrene resin and the polyolefin resin is 50% by weight or more (A Layer). When the base layer part includes a large number of layers, and the layer A includes two or more layers as the layer in the base layer part, the shrink label of the present invention suppresses a decrease in heat shrinkability and is excellent in transparency. And can maintain high relaxation deterrence.

  The base layer portion is not particularly limited, but preferably includes at least one layer (B layer) containing 50% by weight or more of a polyolefin-based resin as a layer in the base layer portion. It is preferable that the base layer portion has a B layer, because the relaxation deterrence of the shrink label can be further maintained.

  In the present specification, the “base layer portion” is a portion sandwiched between the surface layers in the shrink film of the present invention. The base layer portion has a structure in which 5 to 65 layers are laminated, and is a layer in the base layer portion, and is sandwiched between two outermost layers located on both end faces in the thickness direction and the outermost layer. It is comprised by the some intermediate | middle layer located inside thickness direction. That is, the base layer portion has a configuration of [outermost layer / intermediate layer /... / Intermediate layer / outermost layer]. The “layer containing a polystyrene resin and a polyolefin resin, and the total content of the polystyrene resin and the polyolefin resin is 50% by weight or more” may be referred to as “A layer”. The “layer containing 50% by weight or more of polyolefin resin” may be referred to as “B layer”. All or some of the plurality of A layers in the base layer portion may be the same layer, or may be different from each other within the range of the A layer defined in the present application. Layer having different resin composition and layer thickness). Similarly, when there are a plurality of B layers in the base layer portion, all or some of the plurality of B layers in the base layer portion may be the same layer, or Different layers (layers having different resin compositions and layer thicknesses) may be used. Moreover, the said base layer part may contain layers (other layers) other than A layer and B layer within the range which does not impair the effect of this invention. Further, each of the A layer and the B layer may be an outermost layer of the base layer portion, an intermediate layer, or both may be included in the base layer portion.

  In the base layer portion, the layers in the adjacent base layer portions have different raw material compositions. This is because, if the raw material compositions of the layers in the adjacent base layer portions are the same, the interface between adjacent layers in the base layer portion is not visible and overlaps to form one layer.

  The layer in the base layer part is a resin layer. The resin layer should just contain the thermoplastic resin at least. The content of the thermoplastic resin in the resin layer is not particularly limited, but is preferably 50% by weight or more, more preferably 70% by weight or more, and still more preferably 90% by weight based on the total weight (100% by weight) of the resin layer. % Or more, particularly preferably 95% by weight or more.

  The thermoplastic resin is not particularly limited. For example, polyester resin, polystyrene resin, polyolefin resin, vinyl chloride resin, polycarbonate resin, polyamide resin, thermoplastic elastomer, acrylic resin, urethane resin. And vinyl acetate resin.

  Although the layer in the said base layer part is not specifically limited, From a viewpoint of the heat shrinkable improvement of a shrink film, the polymer plasticizer may be included. Examples of the polymer plasticizer include rosin resin (rosin, polymerized rosin, hydrogenated rosin and derivatives thereof, resin acid dimer, etc.), terpene resin (terpene resin, aromatic modified terpene resin, hydrogenated terpene resin). Terpene-phenol resins, etc.), petroleum resins (aliphatic petroleum resins, aromatic petroleum resins, alicyclic petroleum resins, etc.). Among these, petroleum resin is preferable. Only 1 type may be used for the said polymeric plasticizer, and 2 or more types may be used for it. As the polymer plasticizer, “Arcon” manufactured by Arakawa Chemical Industry Co., Ltd., “Clearon” manufactured by Yashara Chemical Co., Ltd., “Imabe” manufactured by Idemitsu Kosan Co., Ltd., etc. are commercially available.

  The layer in the base layer part may contain other components (additional components) as necessary, for example, lubricants, fillers, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, antifogging agents, flame retardants. , Coloring agents, pinning agents (alkaline earth metals), softeners, compatibilizers, and the like may be included. These components may use only 1 type and may use 2 or more types. Moreover, the layer in the said base layer part may contain the collection | recovery raw material (recycled material) in the range which does not impair the effect of this invention. The recovered material is a recycled material composed of non-product parts before and after commercialization, film edges, etc., remaining parts when product films are collected from intermediate products, non-standard product film scraps, and polymer scraps. However, the recovered raw material is preferably a product (so-called self-recovered product) produced from the production of the shrink film of the present invention.

(A layer)
The A layer is a resin layer containing a polystyrene resin and a polyolefin resin in the layer, and the total content of the polystyrene resin and the polyolefin resin is 50% by weight or more. When the base layer portion has a plurality of A layers, the shrink label of the present invention has a shrink film that suppresses a decrease in heat shrinkability, maintains relaxation inhibition, and is excellent in transparency.

  The A layer contains a polystyrene resin and a polyolefin resin as essential components. Each of the polystyrene-based resin and the polyolefin-based resin may be used alone or in combination of two or more. Further, the A layer is not particularly limited, but may contain a resin other than a polystyrene resin and a polyolefin resin.

  Examples of the polystyrene resin (that is, the polystyrene resin contained in the A layer) include the polystyrene resins exemplified and explained as the polystyrene resin contained in the surface layer. The polystyrene resin may be the same polystyrene resin as the polystyrene resin contained in the surface layer, or may be a different polystyrene resin.

  As the polystyrene resin, a styrene-diene copolymer is preferable from the viewpoint of shrinkage characteristics of shrink labels and interlayer strength, more preferably a styrene-butadiene copolymer, and still more preferably a styrene-butadiene block copolymer. Polymers, particularly preferably styrene-butadiene block copolymers having styrene blocks at both ends, most preferably SBS.

  Although the content of the structural unit derived from the styrene monomer in the styrene-diene copolymer is not particularly limited, it is 50 with respect to the total weight (100% by weight) of the styrene-diene copolymer. % By weight or more and less than 100% by weight is preferable, more preferably 70 to 95% by weight, and still more preferably 80 to 95% by weight. The content of the structural unit derived from diene in the styrene-diene copolymer is not particularly limited, but is 0% by weight with respect to the total weight (100% by weight) of the styrene-diene copolymer. More than 50% by weight, more preferably 5 to 30% by weight, still more preferably 5 to 20% by weight. In particular, it is preferable that the content of the structural unit derived from the conjugated diene in the styrene-diene copolymer satisfies the above range.

  The polyolefin resin is a polymer composed of olefin as an essential monomer component (including an olefin elastomer), that is, a polymer containing at least a structural unit derived from olefin in a molecule (in one molecule). It is a coalescence. Although it does not specifically limit as said olefin, For example, alpha-olefins, such as ethylene, propylene, 1-butene, 4-methyl-1- pentene, are mentioned.

  Examples of the polyolefin resin include a polymer composed of ethylene as an essential monomer component (polyethylene resin), a polymer composed of propylene as an essential monomer component (polypropylene resin), and an ionomer. And amorphous cyclic olefin-based polymers. The polyolefin resin is not particularly limited, but among them, a polyethylene resin, a polypropylene resin, and an amorphous cyclic olefin polymer are preferable, a polyethylene resin, a polypropylene resin, and more preferably a polypropylene resin. It is. Only 1 type may be used for the said polyolefin resin, and 2 or more types may be used for it.

  The polyethylene-based resin is a polymer composed of ethylene as an essential monomer component, that is, a polymer containing at least a structural unit derived from ethylene in a molecule (in one molecule). Examples of the polyethylene resin include ethylene homopolymers, copolymers composed of ethylene and one or more monomer components (monomer components other than ethylene) as essential monomer components (ethylene copolymer). Polymer).

  Examples of monomer components other than ethylene include: α-olefins; vinyl monomers such as vinyl chloride and vinyl acetate; (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, 5 -Unsaturated carboxylic acids such as norbornene-2,3-dicarboxylic acid; unsaturated carboxylic anhydrides such as maleic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, tetrahydrophthalic anhydride; Methyl) methacrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylic 3-hydroxypropyl acid, glycidyl (meth) acrylate, monoethyl maleate, male Unsaturated carboxylic acid esters such as diethyl, acrylamide, methacrylamide, unsaturated amides or imides, such as maleimide; (meth) sodium acrylate, and the like unsaturated carboxylic acid salt such as zinc (meth) acrylate. Only 1 type may be used for monomer components other than the said ethylene, and 2 or more types may be used for it.

  Examples of the α-olefin include 4 to 4 carbon atoms such as 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene. 20 α-olefins (preferably α-olefins having 4 to 8 carbon atoms) and the like. Only 1 type may be used for the said alpha olefin, and 2 or more types may be used for it.

  Examples of the ethylene copolymer include a copolymer composed of ethylene and one or more α-olefins as essential monomer components (ethylene-α-olefin copolymer); an ethylene-vinyl acetate copolymer. Polymer (EVA); ethylene-carboxylic acid copolymer such as ethylene-acrylic acid copolymer (EAA) and ethylene-methacrylic acid copolymer (EMAA); ethylene-ethyl acrylate copolymer (EEA) ), And ethylene-carboxylic acid ester copolymers such as ethylene-methyl methacrylate copolymer (EMMA).

Examples of the polyethylene resin include low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE), and are not particularly limited, but LLDPE is particularly preferable from the viewpoint of heat shrinkability. The LDPE refers to polyethylene having a low density of about 0.850 to 0.945 g / cm ³ which contains at least a structural unit derived from ethylene and is produced by a high pressure method. The LLDPE refers to a low-density polyethylene of about 0.850 to 0.945 g / cm ³ having at least a structural unit derived from ethylene, produced by a medium / low pressure method, and having a short chain branch.

  Content of the structural unit derived from ethylene in the polyethylene resin (100 wt%), that is, content of ethylene in all monomer components (100 wt%) constituting the polyethylene resin is particularly limited. However, it is preferably 80% by weight or more, more preferably 85% by weight or more, still more preferably 90% by weight or more, and the upper limit is 100% by weight, 99% by weight, 98% by weight, or 95% by weight. May be.

  Among the polyethylene resins, an ethylene-α-olefin copolymer is particularly preferable. The ethylene-α-olefin copolymer may contain structural units derived from monomer components other than ethylene and α-olefin. Further, the content of structural units derived from the α-olefin in the ethylene-α-olefin copolymer (100% by weight), that is, all monomer components constituting the ethylene-α-olefin copolymer ( The content of α-olefin in (100 wt%) is not particularly limited, but is preferably 1 to 20 wt%, more preferably 2 to 15 wt%, and still more preferably 5 to 10 wt%. The total of the content of structural units derived from ethylene and the content of structural units derived from α-olefin in the ethylene-α-olefin copolymer (100 wt%), that is, the ethylene-α-olefin copolymer The total of ethylene content and α-olefin content in all monomer components (100% by weight) constituting the coalescence is not particularly limited, but is preferably 90% by weight or more, more preferably 95% by weight or more. More preferably, it is 97% by weight or more, and particularly preferably 98% by weight or more.

Although the density of the said polyethylene-type resin is not specifically limited, 0.870-0.950g / cm < ³ > is preferable, More preferably, it is 0.890-0.935g / cm < ³ >. The melt flow rate (MFR) (temperature 190 ° C., load 2.16 kg) of the polyethylene resin is not particularly limited, but is preferably 1 to 30 g / 10 minutes from the viewpoint of melt extrusion suitability and productivity. Preferably it is 1-10 g / 10min.

  Although the said polyethylene-type resin is not specifically limited, The polyethylene-type resin (metallocene catalyst-type polyethylene resin) obtained by superposing | polymerizing using a metallocene catalyst is preferable. As the metallocene catalyst, a known or commonly used metallocene catalyst for olefin polymerization can be used. The polymerization method (copolymerization method) of the polyethylene resin is not particularly limited, and examples thereof include known polymerization methods such as a slurry method, a solution polymerization method, and a gas phase method.

  As the polyethylene-based resin, commercially available products may be used. For example, “Umerit 4540F”, “Umerit 3540F”, “Umerit 2540F”, “Umerit 1540F”, “Umerit 0540F”, “Umerit 5540F”, “ "Umerit 2040FC", "Umerit 0520F", "Umerit 1520F", "Umerit 0520F", "Umerit 715FT", Prime Polymer's "Evolue SP1520", "Evolue SP2040", Nippon Polyethylene "Kernel KF260T" “Kernel KF360T”, “Kernel KF380”, “Kernel KS340T” (metallocene catalyst system LLDPE), “F234” (LDPE manufactured by Ube Maruzen Polyethylene Co., Ltd.) , Ube Maruzen Polyethylene Co., Ltd. "V206", Japan polyethylene Co., Ltd. "Novatec EVA Series" (or more, EVA) is and available in the market.

  Although it does not specifically limit as said polypropylene resin, For example, the homopolymer of propylene (homopolypropylene); Propylene and 1 or more types of monomer components (monomer components other than propylene) are essential monomer components The copolymer comprised as (propylene copolymer) etc. are mentioned.

  Examples of the monomer component other than propylene include monomer components exemplified and explained as ethylene and monomer components other than ethylene in the above-described ethylene copolymer. As the propylene copolymer, among them, a copolymer composed of propylene and one or more α-olefins as essential monomer components (propylene-α-olefin copolymer) is preferable.

  The propylene-α-olefin copolymer is a copolymer containing at least a structural unit derived from propylene and a structural unit derived from an α-olefin in a molecule (in one molecule). Examples of the α-olefin used as a copolymerization component of the propylene-α-olefin copolymer include ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-heptene. , 1-octene, 1-nonene, 1-decene and the like, such as α-olefin having 4 to 20 carbon atoms. Only 1 type may be used for the said alpha olefin, and 2 or more types may be used for it. The propylene copolymer (propylene-α-olefin copolymer or the like) may be a block copolymer, a random copolymer, or a graft copolymer. Among these, a random copolymer and a graft copolymer are preferable, and a random copolymer is more preferable.

  Among the above, the propylene-α-olefin copolymer is particularly preferably a propylene-ethylene copolymer. In the propylene-ethylene copolymer, the ratio of ethylene to propylene is, for example, the former / the latter (weight ratio) = 1/99 to 40/60 (preferably 2/98 to 30/70, more preferably 3/97. About 25/75, more preferably about 3/97 to 20/80). The propylene-ethylene copolymer may be in any form of a block copolymer, a random copolymer, and a graft copolymer, and an α-olefin other than ethylene and propylene is further copolymerized. Also good. As said propylene-ethylene copolymer, a propylene-ethylene graft copolymer and a propylene-ethylene random copolymer are preferable, and a propylene-ethylene random copolymer is more preferable. In the case of the propylene-ethylene random copolymer, the ratio of ethylene to propylene is more preferably the former / the latter (weight ratio) = 3/97 to 5/95, particularly preferably 3/97 to 4.5 / 95. 5. The propylene-ethylene random copolymer preferably has an isotactic index of 90% or more from the viewpoint of low-temperature shrinkage and the strength of shrink labels.

  The propylene-ethylene graft copolymer is particularly preferably a propylene-ethylene graft copolymer, which is a modified polypropylene resin obtained by graft copolymerizing a polyethylene resin with polypropylene as the main chain. When the propylene-ethylene graft copolymer is used as the polyolefin-based resin, the shrinkage of the shrink film (or shrink label) can be suppressed, and the heat shrinkage rate during shrink processing can be more effectively maintained. .

  Although the said polypropylene resin is not specifically limited, The polypropylene resin obtained by superposing | polymerizing using a metallocene catalyst (metallocene catalyst polypropylene resin) is preferable. As the metallocene catalyst, a known or commonly used metallocene catalyst for olefin polymerization can be used. It does not specifically limit as a polymerization method (copolymerization method) of the said polypropylene resin, Well-known polymerization methods, such as a slurry method, solution polymerization method, and a gas phase method, are mentioned.

  The propylene content in the polypropylene resin (that is, the content of the structural unit derived from propylene in the polypropylene resin) is not particularly limited, but from the viewpoint of heat shrinkability, strength, and density of the shrink film, It is preferably 50% by weight or more, more preferably 70% by weight or more, and still more preferably 80% by weight or more with respect to the total weight (100% by weight) of the resin. The upper limit of the propylene content may be 100% by weight.

  Further, the content of structural units derived from the α-olefin in the propylene-α-olefin copolymer (100% by weight), that is, all the monomer components constituting the propylene-α-olefin copolymer ( The content of α-olefin in (100 wt%) is not particularly limited, but is preferably 1 to 40 wt%, more preferably 2 to 30 wt%, and still more preferably 3 to 25 wt%. The total of the content of the structural unit derived from propylene and the content of the structural unit derived from α-olefin in the propylene-α-olefin copolymer (100% by weight), that is, the propylene-α-olefin copolymer The total of the content of propylene and the content of α-olefin in all monomer components (100% by weight) constituting the coalescence is not particularly limited, but is preferably 90% by weight or more, more preferably 95% by weight or more. More preferably, it is 97% by weight or more, and particularly preferably 98% by weight or more.

Although the density of the said polypropylene resin is not specifically limited, 0.850-0.950g / cm < ³ > is preferable.

  Commercially available products may be used as the polypropylene-based resin. “Wintech WFX6”, “Wintech WFX4”, “Wintech WFX4T”, “Wintech WFX4TA”, “Wintech WFW4” manufactured by Nippon Polypro Co., Ltd. , "Wintech WFW4F", "Wintech WFW5T", "Wintech 1987FC" (above, metallocene catalyst-based propylene-ethylene random copolymer), "Zeras # 7000", "Zeras # 5000" manufactured by Mitsubishi Chemical Corporation “Novatech FB3HAT”, “Novatech FW3GT”, “Novatech FW4BT”, “Novatech FX4E”, “Novatech FX4G” (polypropylene resin), “Vistamax” manufactured by ExxonMobil Chemical Co., Ltd. 3020FL "," Vistamaxx 3980 "," Vistamaxx 3980FL "," Vistamaxx 6102 "(or a propylene-based elastomer, a propylene - ethylene random copolymer) and the like are commercially available.

  Examples of the amorphous cyclic olefin polymer include a copolymer of an α-olefin such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene and at least one cyclic olefin. (Sometimes referred to as "cyclic olefin copolymer") and cyclic olefin ring-opening polymer or hydrogenated product thereof (sometimes referred to as "cyclic olefin ring-opening polymer or hydrogenated product thereof") Is mentioned. The cyclic olefin copolymer, the cyclic olefin ring-opening polymer, or the hydrogenated product thereof also includes a graft-modified product thereof.

Examples of the cyclic olefin used in the amorphous cyclic olefin-based polymer include bicyclo [2.2.1] hept-2-ene (norbornene), tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, hexacyclo [6.6.1.1 ^3,6 . 1 ^10,13 . 0 ^2,7 . 0 ^9,14] -4-heptadecene, octacyclo [8.8.0.1 ^2,9. 1 ^4,7 . 1 ^11,18 . 1 ^13,16 . 0 ^3,8 . 0 ^12,17 ] -5-docosene, pentacyclo [6.6.1.1 ^3,6 . 0 ^2,7 . 0 ^9,14] -4-hexadecene, heptacyclo-5-icosene, heptacyclo-5-henicosenoic, tricyclo [4.3.0.1 ^{2, 5]-3-decene,} tricyclo [4.4.0.1 ^{2 , 5} ] -3-undecene, pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene, pentacyclopentadecadiene, pentacyclo [4.7.0.1 ^2,5 . 0 ^8,13 . 1 ^9,12] -3-pentadecene, Nonashikuro [9.10.1.1 ^{4, 7.} 1 ^13,20 . 1 ^15,18 . 0 ^2,10 . 0 ^12,21 . 0 ^14,19] -5-pentacosene and the like polycyclic olefins such. Of these, norbornene is preferable. These cyclic olefins may have substituents such as ester groups such as methoxycarbonyl and ethoxycarbonyl groups, alkyl groups such as methyl groups, haloalkyl groups, cyano groups, and halogen atoms in the ring.

  The cyclic olefin copolymer is, for example, the α-olefin and the cyclic olefin in hydrocarbon solvents such as hexane, heptane, octane, cyclohexane, benzene, toluene, xylene, so-called Ziegler catalyst, metallocene catalyst, etc. It can be obtained by polymerization using a catalyst. Such cyclic olefin copolymers are commercially available, and for example, “Apel” manufactured by Mitsui Chemicals, Inc., “TOPAS” manufactured by Polyplastics Co., Ltd., and the like can be used.

  The ring-opening polymer of the cyclic olefin or the hydrogenated product thereof is usually obtained by subjecting one or more of the cyclic olefins to metathesis polymerization (ring-opening polymerization) using a molybdenum compound or a tungsten compound as a catalyst. The polymer obtained can be further hydrogenated. Such ring-opened polymers of cyclic olefins or hydrogenated products thereof are commercially available. For example, “Arton” manufactured by JSR Corporation, “Zeonex” manufactured by Nippon Zeon Co., Ltd., “Zeonor”, and the like can be used.

  The amorphous cyclic olefin polymer is not particularly limited, but a cyclic olefin copolymer is more preferable. When the polyolefin resin is mixed, the cyclic olefin copolymer has a high compatibility and compatibility with the polyolefin resin, and a shrink film excellent in transparency and impact resistance can be obtained.

  The glass transition temperature (Tg) of the amorphous cyclic olefin-based polymer is not particularly limited, but is preferably 50 to 80 ° C, more preferably 60 to 80 ° C, and still more preferably 60 to 75 from the viewpoint of stretchability. It is 65 degreeC, Most preferably, it is 65-75 degreeC (especially about 70 degreeC). The glass transition temperature of the amorphous cyclic olefin-based polymer can be adjusted by the type of monomer component (for example, cyclic olefin) and the blending ratio thereof.

  When the amorphous cyclic olefin polymer is a cyclic olefin copolymer, the content of the structural unit derived from the cyclic olefin (for example, norbornene) in the cyclic olefin copolymer is not particularly limited. From the viewpoint of shrinkability, the content is preferably 50 to 75% by weight, more preferably 60 to 70% by weight, based on the total weight (100% by weight) of the cyclic olefin copolymer. For example, the norbornene content in the cyclic olefin copolymer is preferably in the above range.

  The polyolefin resin is preferably an ethylene homopolymer, an ethylene-α-olefin copolymer, a propylene homopolymer, or a propylene-α-olefin copolymer, and a propylene homopolymer, propylene-α-olefin copolymer. More preferred are metallocene catalyst-based polypropylene homopolymers, metallocene catalyst-based propylene-α-olefin copolymers (particularly metallocene catalyst-based propylene-α-olefin random copolymers, among which metallocene catalyst-based propylene-ethylene is preferred. Random copolymers) are more preferred.

  The total content of the polystyrene resin and the polyolefin resin in the A layer is 50% by weight or more, preferably 70% by weight or more, more preferably 75% with respect to the total weight (100% by weight) of the A layer. % By weight or more. The upper limit of the content is not particularly limited, and may be 100% by weight. If the said content is less than 50 weight%, it will become difficult to maintain the high heat-shrinkability of a shrink label and relaxation inhibitory property highly. In addition, when two or more types of polystyrene resins and polyolefin resins are included in the A layer, the above “contents of the polystyrene resin and the polyolefin resin in the A layer” are all included in the A layer. The total content of polystyrene resin and polyolefin resin.

  The content ratio of the polystyrene resin and the polyolefin resin in the layer A [polystyrene resin content (% by weight) / polyolefin resin content (% by weight)] (weight ratio) is not particularly limited. 80-80 / 20 is preferable, More preferably, it is 30 / 70-80 / 20, More preferably, it is 40 / 60-70 / 30. When the content ratio of the polystyrene resin is 20/80 or more, the heat shrinkability can be more effectively maintained, which is preferable. Moreover, the interlayer strength between the surface layer and the base layer and the rigidity of the shrink label are improved, which is preferable. When the content ratio of the polyolefin-based resin is 80/20 or more, the relaxation deterrence due to the inclusion of the polyolefin-based resin can be more effectively maintained, which is preferable. Moreover, the interlayer strength between the surface layer and the base layer is improved, which is preferable. Furthermore, from the viewpoint of reducing the density of the shrink label, the content ratio is preferably 20/80 to 50/50, more preferably 25/75 to 45/55, and further preferably 30/70 to 40/60. is there.

  The content of the polystyrene-based resin in the A layer is not particularly limited, but is preferably 10% by weight or more, more preferably 15% by weight or more with respect to the total weight (100% by weight) of the A layer.

  The content of the polyolefin-based resin in the A layer is not particularly limited, but is preferably 10% by weight or more, more preferably 15% by weight or more with respect to the total weight (100% by weight) of the A layer.

  The content of the polymeric plasticizer (especially petroleum resin) in the A layer in the case of adding the polymeric plasticizer is not particularly limited, but is 1 to 1 with respect to the total weight (100 wt%) of the A layer. 25 weight% is preferable, More preferably, it is 2-20 weight%, More preferably, it is 3-15 weight%. When the content is 1% by weight or more, the effect of the polymer plasticizer can be sufficiently obtained. When the said content exceeds 25 weight%, a shrink film may become weak.

  The content of the compatibilizer in the A layer in the case of adding a compatibilizer for the purpose of compatibilizing the polystyrene resin and the polyolefin resin is not particularly limited, but is the total weight (100 wt%) of the A layer. On the other hand, 1-30 weight% is preferable, More preferably, it is 3-20 weight%, More preferably, it is 5-15 weight%. In addition, since hydrogenated styrene elastomers can be used effectively as compatibilizers for polystyrene resins and polyolefin resins, hydrogenated styrene elastomers may be used in a content within the above range for the purpose of compatibilization. it can.

  The layer A may contain a recovered raw material (recycled material) as long as the effects of the present invention are not impaired. In this case, the content of the recovered raw material in the A layer is preferably 1 to 95% by weight with respect to the total weight (100% by weight) of the A layer from the viewpoint of recyclability.

(B layer)
The B layer is a resin layer containing 50% by weight or more of a polyolefin resin in the layer. When the base layer portion contains at least one B layer, the shrink label of the present invention is preferable because it can maintain a relatively high relaxation inhibiting property.

  In addition, since the sum total of content of a polystyrene resin and polyolefin resin will be 50 weight% or more when the said B layer contains a polystyrene resin further in a layer, it is also said A layer. When the B layer contains a polystyrene resin in the layer, the B layer and the A layer are layers having different raw material compositions (that is, two A layers having different raw material compositions), and the polystyrene resin in each layer. And the difference in the content of at least one of the polyolefin-based resins is preferably 10% by weight or more, and more preferably 20% by weight or more.

  The B layer contains a polyolefin-based resin as an essential component. Only 1 type may be used for the said polyolefin resin, and 2 or more types may be used for it. Moreover, the B layer is not particularly limited, but may contain a resin other than the polyolefin-based resin.

  Examples of the polyolefin resin (that is, the polyolefin resin contained in the B layer) include the polyolefin resins exemplified and explained as the polyolefin resin contained in the A layer. The polyolefin resin may be the same polyolefin resin as the polyolefin resin contained in the layer A, or may be a different polyolefin resin.

  The polyolefin resin is preferably an ethylene homopolymer, an ethylene-α-olefin copolymer, a propylene homopolymer, or a propylene-α-olefin copolymer, and a propylene homopolymer, propylene-α-olefin copolymer. More preferred are metallocene catalyst-based polypropylene homopolymers, metallocene catalyst-based propylene-α-olefin copolymers (particularly metallocene catalyst-based propylene-α-olefin random copolymers, among which metallocene catalyst-based propylene-ethylene is preferred. Random copolymers) are more preferred.

  The content of the polyolefin-based resin in the B layer is 50% by weight or more, preferably 70% by weight or more, more preferably 75% by weight or more with respect to the total weight (100% by weight) of the B layer. The upper limit of the content is not particularly limited, and may be 100% by weight. It is preferable for the content to be 50% by weight or more because the relaxation deterrence of the shrink label can be kept higher. In addition, when 2 or more types of polyolefin resin is contained in B layer, said "content of polyolefin resin in B layer" is content of all the polyolefin resins contained in B layer. is there.

  The content of the polystyrene-based resin in the B layer is not particularly limited, but may be less than 15% by weight or less than 10% by weight with respect to the total weight (100% by weight) of the B layer. .

  The content of the polymer plasticizer (particularly petroleum resin) in the B layer in the case of adding the polymer plasticizer is not particularly limited, but is 5 to 5% with respect to the total weight (100% by weight) of the B layer. 30 weight% is preferable, More preferably, it is 10-25 weight%. When the content is 5% by weight or more, the effect of the polymer plasticizer can be sufficiently obtained. When the said content exceeds 30 weight%, a shrink film may become weak.

  B layer may contain the collection | recovery raw material (recycled material) in the range which does not impair the effect of this invention. In this case, the content of the recovered raw material in the B layer is preferably 1 to 50% by weight with respect to the total weight (100% by weight) of the B layer.

(Outermost layer)
The outermost layer is a layer of the base layer portion and is a layer located on both end faces in the thickness direction. The outermost layer may be the A layer or the B layer, or may be a layer other than the A layer and the B layer (another layer). The outermost layer is not particularly limited, but a resin layer containing as an essential component at least one resin selected from the group consisting of EVA, modified polystyrene resins, styrene elastomers, and olefin elastomers; A layer is preferred A layer is particularly preferred. When the outermost layer of the base layer portion is the A layer, the shrink label is preferable because, in addition to improving the interlayer strength between the surface layer and the base layer portion, the shrink label and the heat shrinkability can be kept higher. In the present specification, the “at least one resin selected from the group consisting of EVA, modified polystyrene resins, styrene elastomers, and olefin elastomers” may be referred to as “specific resin”. Further, the above-mentioned “resin layer containing at least one resin selected from the group consisting of EVA, modified polystyrene resin, styrene elastomer, and olefin elastomer as an essential component”, that is, “containing a specific resin as an essential component” The “resin layer” may be referred to as a “specific resin layer”.

  When the outermost layer is the specific resin layer, the content of the specific resin in the specific resin layer is not particularly limited, but is 50% by weight with respect to the total weight (100% by weight) of the specific resin layer. The above is preferable, more preferably 70% by weight or more, and still more preferably 75% by weight or more. The upper limit of the content is not particularly limited, and may be 100% by weight. When the specific resin layer contains two or more types of the specific resin, the content of the specific resin is the total content of all the specific resins in the specific resin layer.

(Middle layer)
The intermediate layer is a layer constituting the base layer portion, and is a layer other than the outermost layer. Although the said base layer part is not specifically limited, The layer for providing the various functions of a base layer part etc. can be used as said intermediate | middle layer, for example, intermediate layers other than A layer, B layer, A layer, and B layer Layer (other intermediate layer). The base layer portion preferably includes at least a B layer as the intermediate layer, and more preferably includes at least an A layer and a B layer.

  As said other intermediate | middle layer, layers other than A layer and B layer are mentioned among the layers illustrated and demonstrated as a layer in the above-mentioned base layer part. Among these, the specific resin layer described as the outermost layer and a layer containing 50% by weight or more of the polystyrene-based resin are preferable.

  When there are a plurality of the other intermediate layers in the base layer portion, all or some of the plurality of other intermediate layers in the base layer portion may be the same layer, Different layers (layers having different resin compositions and layer thicknesses) may be used.

  When the other intermediate layer is a layer containing 50% by weight or more of a polystyrene resin, the content of the polystyrene resin in the other intermediate layer is based on the total weight (100% by weight) of the other intermediate layer. And 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, and particularly preferably 90% by weight or more. The upper limit of the content is not particularly limited, and may be 100% by weight.

(Layer structure and physical properties of the base layer)
The number of layers included in the base layer portion is 5 to 65 layers, preferably 5 to 33 layers, and more preferably 9 to 33 layers. When the number of layers is less than 5, the effect of the base layer is not sufficient, and it is difficult to maintain high relaxation deterrence. In addition, the shrinkage of the shrink label is weak, the effect of improving the interlayer strength due to the multi-layering is small, and delamination is likely to occur during shrinking (heating). Further, when the number of layers is 5 or more, the layer thickness of each layer constituting the base layer portion becomes thin and light scattering is difficult, so that the haze of the shrink film is reduced, and the base layer portion is the same as a single layer. Excellent transparency compared to thick shrink film. On the other hand, if the number of layers exceeds 65 layers, the thickness of each layer in the base layer portion such as the A layer (thickness per layer) when the thickness (total thickness) of the shrink film is in a range suitable for shrink labels. Becomes too thin, the effect of using the A layer becomes small, and it becomes difficult to keep the heat shrinkability and relaxation inhibiting property of the shrink label high. Moreover, the rigidity of a shrink film and a shrink label may fall and a waist may become weak.

  The base layer portion includes two or more A layers as layers in the base layer portion, preferably three layers or more, more preferably four layers or more, and still more preferably five layers or more. The number of layers A is not particularly limited as long as it is 65 layers or less, but the upper limit is preferably 32 layers, more preferably 16 layers. Since the A layer is a layer containing 50% by weight or more of a mixed resin of polystyrene resin and polyolefin resin, the shrink label of the present invention having the shrink film of the present invention when the base layer portion has two or more A layers. Can sufficiently retain heat shrinkability and relaxation deterrence.

  When the said base layer part contains B layer, the number of layers of B layer in a base layer part is 1 layer or more, Preferably it is 2 layers or more, More preferably, it is 4 layers or more. The upper limit of the number of layers of the B layer is not particularly limited, but may be 63 layers or less, preferably 33 layers or less, more preferably 17 layers or less. In addition, when B layer is also A layer, the upper limit of the number of layers of B layer may be 65 layers.

  When the said base layer part has B layer, although the total number of layers of A layer and B layer is not specifically limited, 5-65 layer is preferable, More preferably, it is 5-33 layer, More preferably, it is 9-33 layer is there.

  When the said base layer part has B layer, it is preferable that the said base layer part has a laminated structure with which A layer and B layer adjoin. When the base layer portion has the above-described laminated structure, the A layer has no problem in adhesion with the B layer, and can be used to optimize the shrinkage rate and increase the compressive strength and rigidity of the shrink label. ,preferable.

  The base layer portion is not particularly limited, but preferably has three or more interfaces formed by adjoining (directly laminating) the A layer and the B layer. The number of the interfaces is not particularly limited, but is preferably 3 or more, more preferably 4 or more, and still more preferably 5 or more. The upper limit of the number of interfaces is 64, preferably 32. It is preferable that the base layer portion has three or more of the above interfaces because the tearability of the label is improved, and stress due to the impact of the drop is dispersed and relaxed at each interface when dropped and the drop resistance is also improved. In addition, since the base layer portion is multilayered, the label is difficult to delaminate even when the interlayer strength at the interface is relatively weak. In the present specification, the “interface where the A layer and the B layer are formed adjacent to each other” may be referred to as “interface [A / B]”.

  When the base layer portion has a B layer, in the base layer portion, the B layer is not particularly limited, but is preferably interposed between two or more A layers, and is interposed between all the A layers in the base layer portion. More preferably. In particular, in the base layer portion, the A layer and the B layer are not particularly limited, but are preferably alternately stacked, and more preferably directly stacked alternately without any other layer. That is, the base layer portion most preferably includes 5 to 65 layers in total, alternating between A layers and B layers.

  The base layer portion may include 5 to 65 layers, and two or more layers A may be included as layers in the base layer portion. The layered structure of the base layer part is not particularly limited. Specifically, the layered structure (A layer / B layer) that repeats “A layer / B layer” as a repeating unit without intervening layers other than the A layer and the B layer. Layer / A layer / B layer /... / A layer / B layer / A layer), (B layer / A layer / B layer / A layer /... / B layer / A layer / B layer) , (A layer / B layer / A layer / B layer /.../ A layer / B layer) or (B layer / A layer / B layer / A layer / ...... B layer / A layer) It is preferable that Further, the outermost layers on both surfaces of the base layer portion may be the A layer or the B layer, but the A layer is preferable on both surfaces. When layer A is used as the outermost layer of the base layer portion, delamination that is likely to occur during shrink processing (during thermal shrinkage) between the surface layer and the base layer portion can be suppressed, which is preferable. Moreover, since the stress at the time of thermal shrinkage is reduced and the interlayer is difficult to shift, the rigidity can be increased without decreasing the interlayer strength, which is preferable.

  Although not particularly limited, in the base layer portion, it is preferable that all the A layers are formed from the same raw material, and it is preferable that all the B layers are formed from the same raw material. That is, the A layers and the B layers are preferably formed from the same raw material. Particularly, all the A layers are preferably layers having the same composition, and all the B layers are preferably layers having the same composition.

  In addition, as the laminated structure of the base layer portion, for example, it is composed of an A layer and other layers, and repeats “A layer / other layer” as a repeating unit (A layer / other layer / A layer / other layers). Layer /.../ A layer / other layer / A layer), (other layer / A layer / other layer / A layer /.../ other layer / A layer / other layer), (A layer / other layer / A layer / other layer /.../ A layer / other layer) or (other layer / A layer / other layer / A layer /.../ other) Layer / A layer). The outermost layers on both sides of the base layer portion may be the A layer or other layers.

  In addition, when the base layer portion is formed of only the A layer, the stack configuration of the base layer portion is, for example, using two A layers (A1 layer and A2 layer) having different raw material compositions as “A1 layer / A2 Layered structure (A1 layer / A2 layer / A1 layer / A2 layer /... / A1 layer / A2 layer / A1 layer), (A2 layer / A1 layer / A2 layer / A1 layer / ... / A2 layer / A1 layer / A2 layer), (A1 layer / A2 layer / A1 layer / A2 layer /.../ A1 layer / A2 layer) or (A2 layer / A1 layer / A2 layer / A1 layer /... / A2 layer / A1 layer). The outermost layers on both sides of the base layer may be A1 layers or A2 layers.

  In addition, as the laminated structure of the base layer portion, for example, the outermost layers on both sides are the specific resin layer, and the intermediate layer is “A layer / B layer”, “A layer / other layer”, or “A1 layer / A stacked structure in which the “A2 layer” is repeated as a repeating unit can be given. As such a laminated structure, specifically, when the intermediate layer is configured to repeat “A layer / B layer” as a repeating unit (specific resin layer / A layer / B layer / A layer / B layer) /..../A layer / B layer / A layer / specific resin layer), (specific resin layer / B layer / A layer / B layer / A layer /.../ B layer / A layer / B layer) / Specific resin layer), (specific resin layer / A layer / B layer / A layer / B layer /.../ A layer / B layer / specific resin layer) or (specific resin layer / B layer / A layer / B layer / A layer /... / B layer / A layer / specific resin layer). When the intermediate layer is configured to repeat “A layer / other layer” as a repeating unit (specific resin layer / A layer / other layer / A layer / other layer /.. ./A layer / other) Layer / A layer / specific resin layer), (specific resin layer / other layer / A layer / other layer / A layer /.. ./Other layer / A layer / other layer / specific resin layer) , (Specific resin layer / A layer / other layer / A layer / other layer /.. ./A layer / other layer / specific resin layer) or (specific resin layer / other layer / A layer / other) Layer / A layer /... / Other layer / A layer / specific resin layer). When the intermediate layer is configured to repeat “A1 layer / A2 layer” as a repeating unit (specific resin layer / A1 layer / A2 layer / A1 layer / A2 layer /... / A1 layer / A2 layer / A1 Layer / specific resin layer), (specific resin layer / A2 layer / A1 layer / A2 layer / A1 layer /.../ A2 layer / A1 layer / A2 layer / specific resin layer), (specific resin layer / A1 layer) / A2 layer / A1 layer / A2 layer /.../ A1 layer / A2 layer / specific resin layer) or (specific resin layer / A2 layer / A1 layer / A2 layer / A1 layer /.../ A2 layer) / A1 layer / specific resin layer).

(Configuration of shrink film of the present invention, physical properties, etc.)
The shrink film of the present invention includes the base layer portion and the surface layer. The surface layer is laminated on both sides of the base layer part, and is provided on one side and the other side of the base layer part, respectively.

  Although the thickness (total thickness) of the shrink film of this invention is not specifically limited, 10-100 micrometers is preferable, More preferably, it is 15-50 micrometers, More preferably, it is 20-45 micrometers. The thickness of 10 μm or more is preferable because an effect of improving the rigidity of the shrink label can be sufficiently obtained.

  The thickness of the surface layer (the thickness of one layer) is not particularly limited, but is preferably 1 to 15 μm, more preferably 2 to 10 μm, and still more preferably 2.5 to 8 μm. When the thickness is 15 μm or less, it is possible to suppress a significant decrease in film elongation at room temperature, which is preferable. It is preferable that the thickness is 1 μm or more because the effect of improving the rigidity of the shrink label can be sufficiently obtained. In addition, the thickness of each surface layer of the both surface sides of a base layer part may be the same, and may mutually differ.

  Although the thickness of the said base layer part is not specifically limited, 8-90 micrometers is preferable, More preferably, it is 10-45 micrometers, More preferably, it is 11-40 micrometers. It is preferable that the thickness is 8 μm or more because the rigidity of the shrink label can be made more appropriate.

  The thickness of the layer in the base layer portion (thickness per layer) is not particularly limited, but is preferably 0.2 to 15 μm, more preferably 0.3 to 10 μm. It is preferable that the thickness is 0.2 μm or more because an effect of improving the rigidity of the shrink label can be sufficiently obtained. In addition, as for the thickness of the some layer in the said base layer part, all or one part of them may be the same, and may mutually differ.

  Although the thickness (thickness per layer) of the said base layer part is not specifically limited, 0.2 micrometer or more (for example, 0.2-15 micrometers) is preferable, More preferably, it is 0.3-10 micrometers.

  The thickness of the intermediate layer (thickness per layer) is not particularly limited, but is preferably 0.3 μm or more (for example, 0.3 to 15 μm), more preferably 0.6 to 10 μm.

  The thickness (thickness per layer) of the A layer is not particularly limited, but is preferably 0.2 μm or more (for example, 0.2 to 8 μm), more preferably 0.3 to 6 μm, and still more preferably 0.4 to 8 μm. It is preferable that the thickness is 0.2 μm or more because an effect of improving the rigidity of the shrink label can be sufficiently obtained. In addition, as for the thickness of several A layer in the said base layer part, all or one part of them may be the same, and may mutually differ.

  When the said base layer part contains B layer, the thickness (thickness per layer) of B layer is although it does not specifically limit, 0.2 micrometer or more (for example, 0.2-15 micrometers) is preferable, More preferably, 0.3 It is 10-10 micrometers, More preferably, it is 0.4-8 micrometers. It is preferable that the thickness is 0.2 μm or more because an effect of improving the rigidity of the shrink label can be sufficiently obtained. In addition, when the said base layer part contains multiple B layers, as for the thickness of the some B layer in a base layer part, all or one part of them may be the same, and may mutually differ.

  In the shrink film of the present invention, the ratio of the thickness of the surface layer (total thickness of all surface layers) and the thickness of the base layer [(thickness of the surface layer) :( thickness of the base layer)] is not particularly limited. 1: 1 to 1:14 are preferable, 1: 1 to 1: 8 are more preferable, and 1: 1 to 1: 4 are particularly preferable. It is preferable that the base layer is thicker than 1: 1 because the effect of improving the transparency due to the multilayering can be easily obtained. On the other hand, it is preferable that the surface layer is thicker than 1:14 because the heat shrinkability and rigidity of the shrink label are further improved.

  When the base layer portion includes the B layer, the ratio of the thickness of the A layer (total thickness of all A layers) to the thickness of the B layer (total thickness of all B layers) [(A layer thickness): ( The thickness of the B layer)] is not particularly limited, but is preferably 2: 1 to 1:10, more preferably 1: 1 to 1: 8. It is preferable that the B layer is thicker than 2: 1 because higher transparency and more appropriate heat shrinkage and rigidity can be easily obtained. On the other hand, when the A layer is thicker than the above ratio of 1:10, the adhesive strength between the layers in the base layer is unlikely to decrease, and delamination is less likely to occur.

  In the shrink film of the present invention, two main components, each of which is a combination of a polyester resin and a polystyrene resin, a polyester resin and a polyolefin resin, and a polystyrene resin and a polyolefin resin. When there is an interface where the resin layers (resin layer (P) and resin layer (Q)) are formed adjacent to each other, the delamination strength in the 180 ° direction at 90 ° C. of the interface [P / Q] is not particularly limited. Is preferably 2N or more, more preferably 3N or more, and still more preferably 4N or more. The upper limit of the delamination strength in the 180 ° direction at 90 ° C. is not particularly limited, but is preferably 10N, more preferably 8N. When the delamination strength in the 180 ° direction at 90 ° C. is 2N or more, delamination can be hardly caused even during shrink processing. In the present specification, an interface where the resin layer (P) and the resin layer (Q) are formed adjacent to each other may be referred to as “interface [P / Q]”. When there are a plurality of interfaces [P / Q] in the shrink film of the present invention, the delamination strength in the 180 ° direction at 90 ° C. of all the interfaces [P / Q] is 2N or more. When there are a plurality of the same interface [P / Q] in the shrink film, the delamination strength in the 180 ° direction at 90 ° C. of the same interface [P / Q] may be regarded as the same.

  In this specification, the delamination strength in the 180 ° direction at 90 ° C. of the interface is not particularly limited. For example, according to JIS K 6854-2, the delamination strength in the 180 ° direction when heated to 90 ° C. It can be obtained by measuring. Specifically, it can be measured by the following method.

(Measurement method of delamination strength in the direction of 180 ° at 90 ° C. of the interface)
The interface measured from the end surface in the main shrinkage direction of the shrink label (or shrink film) is partially peeled to form a peeled portion (peeled portion) and a portion that is peeled and remains (peeled portion). The said to-be-separated part is fixed to a glass plate using an adhesive tape. Then, it heats to 90 degreeC from the glass plate side. Then, the glass plate is fixed so as not to move, the measurement width is set to 15 mm, and the peeling portion is pulled in the 180 ° direction at a pulling speed of 200 mm / min. The strength at the time of pulling is measured, and the delamination strength in the 180 ° direction at 90 ° C. of the interface for measuring the strength is set. Note that the thin side of the shrink label when peeled is the peeled portion, and the thick side is the peeled portion.

  In the present specification, the “main component” refers to the material (component) that is the most among the materials (components) contained in the layer. In addition, a layer (mixed resin layer) in which two or more types of resins among the resins contained in the layer are present corresponds in principle to any layer containing each of the two or more types of resins as a main component. . For example, a mixed resin layer containing 50% by weight of a polyolefin resin and 50% by weight of a polystyrene resin is a layer mainly composed of a polyolefin resin and also a layer mainly composed of a polystyrene resin. However, when the mixed resin layer is adjacent to a layer mainly composed of one resin as a main component in the mixed resin layer, the mixed resin layer includes a resin other than the one resin as a main component. Corresponds to the layer. For example, when a mixed resin layer containing 50% by weight of a polyolefin-based resin and 50% by weight of a polystyrene-based resin is adjacent to a layer mainly composed of a polyolefin-based resin, the mixed resin layer is mainly made of a polystyrene-based resin. It is a layer used as a component.

  The delamination strength in the 180 ° direction at 90 ° C. is, for example, the raw material composition, raw material properties, film production conditions (for example, extrusion temperature, stretching temperature, stretching ratio) constituting the resin layer (P) or the resin layer (Q). Etc.).

  The shrinkage stress at 90 ° C. of the shrink film of the present invention is not particularly limited, but is preferably 1 to 10N, more preferably 1 to 7N, still more preferably 1 to 5N, and particularly preferably 1 to 3N. It is preferable that the shrinkage stress is 1 N or more because the followability of the shrink label to the container and the like is improved. The shrinkage stress can be adjusted by, for example, the thickness, layer configuration, raw material composition, surface layer, raw material composition or thickness constituting the layer in the base layer portion of the shrink film. In the present specification, the shrinkage stress is measured with a measurement width of 15 mm.

  The shrinkage stress at 90 ° C. of the shrink film of the present invention is preferably smaller than the delamination strength in the 180 ° direction at 90 ° C. of the interface [P / Q]. In this case, delamination can be made even more difficult during shrink processing, which is preferable. When there are a plurality of interfaces [P / Q] in the base layer portion, the shrinkage stress at 90 ° C. of the shrink film of the present invention is the delamination strength in the direction of 180 ° at 90 ° C. of all the interfaces [P / Q]. Is preferably smaller.

  The shrinkage stress at 90 ° C. of the shrink film of the present invention is not particularly limited. For example, both ends of the shrink film are fixed and immersed in warm water at 90 ° C. so that there is no slack in the shrink film. Can be obtained by measuring the stress to be heat-shrinkable. The measuring machine used for the measurement of the shrinkage stress is not particularly limited, and examples thereof include “Shimadzu Autograph (AGS-50G: load cell type 500N)” manufactured by Shimadzu Corporation.

  In the shrink film of the present invention, the interface [P / Q] includes an interface formed by adjoining the outermost layer and the surface layer of the base layer, an interface formed by adjoining the outermost layer and the intermediate layer, a main component It may be an interface formed by adjacent intermediate layers having different resins. In this case, the resin layer (P) and the resin layer (Q) are not particularly limited, but the outermost layer and the surface layer of the base layer portion, the A layer and the B layer, the specific resin layer and the A layer, the specific resin layer, Examples include B layer and two other intermediate layers having different raw material compositions.

  The shrink film of the present invention is a film oriented in at least one direction (for example, a film oriented in one direction or a film oriented in one direction and a direction different from one direction) from the viewpoint of exhibiting shrink characteristics. preferable. Furthermore, it is preferable that all the film layers (surface layer, each layer of the base layer portion including the A layer) are oriented in at least one direction. As the shrink film, in particular, a film oriented in one direction (uniaxially oriented film) or a film oriented in one direction and a direction orthogonal to one direction (biaxially oriented film) is often used. Films (including films that are stretched primarily in one direction and slightly stretched in a direction perpendicular to the one direction and substantially stretched in one direction) are generally used.

  The film oriented in at least one direction can be obtained by stretching an unstretched film in at least one direction. For example, when the film oriented in at least one direction is a uniaxially oriented film, it is obtained by stretching an unstretched film in one direction. When it is a biaxially oriented film, the unstretched film is oriented in one direction and the one direction. It is obtained by stretching in a direction perpendicular to the direction. In addition, the shrink label of this invention can be mainly heat-shrinked in the orientation direction of the shrink film of this invention.

  The shrinkage rate of the shrink film of the present invention (before shrink processing) in the main shrinkage direction at 90 ° C. for 10 seconds (warm water treatment) (sometimes referred to as “thermal shrinkage rate (90 ° C., 10 seconds)”) Although not particularly limited, it is preferably 20% or more (for example, 20 to 90%), more preferably 30% or more (for example, 30 to 85%), and still more preferably 40% or more (for example, 40 to 80%). More preferably, it is 45% or more (for example, 45 to 80%), and more preferably 50% or more (for example, 50 to 80%). When the thermal shrinkage rate (90 ° C., 10 seconds) is less than 20%, the shrink label is not sufficiently contracted in the process of heat-adhering the shrink label to the container, making it difficult to follow the shape of the container. The finish may be poor for the container. The “main shrinkage direction” is a direction having the largest thermal shrinkage rate, and is generally a direction mainly stretched, for example, a film stretched substantially in one direction in the width direction. In the case of the width direction.

  In addition, although the thermal contraction rate (90 degreeC, 10 second) of the direction orthogonal to the main contraction direction of the shrink film (before shrink process) of this invention is not specifically limited, -5-15% is preferable, More preferably -3 to 10%.

The density of the shrink film (before shrink processing) of the present invention is not particularly limited, but is less than 1 g / cm ³ (for example, 0.90 g / cm ³ or more and less than 1 g / cm ³ ) from the viewpoint of reducing the density of the shrink label. Is more preferably 0.97 g / cm ³ or less, and still more preferably 0.95 g / cm ³ or less.

  The shrink film of the present invention is transparent, and the haze (haze) value [conforming to JIS K 7136, converted to a thickness of 40 μm, unit:%] of the shrink film is not particularly limited, but is preferably 10% or less, more preferably 7 % Or less, more preferably 5% or less, and particularly preferably 4.5% or less. When the haze value exceeds 10%, the inside of the shrink film (the side that becomes the container side when the shrink label is attached to the container) is printed, and the shrink label that shows the print through the shrink film (back printed shrink label) When used as a product, the printing may become cloudy and the decorativeness may deteriorate.

[Shrink label]
The shrink label of this invention is a shrink label which at least the shrink film of this invention has. The shrink label of the present invention may have a layer other than the shrink film of the present invention.

(Layers other than the shrink film of the present invention)
The layer other than the shrink film of the present invention contained in the shrink label of the present invention is not particularly limited, but other film layers such as a printing layer, a nonwoven fabric or a foamed sheet, an adhesive layer (pressure sensitive adhesive layer, heat sensitive layer). Adhesive layer, etc.), protective layer, anchor coat layer, primer coat layer, coating layer, antistatic layer, aluminum vapor deposition layer and the like.

(Print layer)
The print layer is not particularly limited, and examples thereof include known or commonly used print layers used in shrink labels. In addition, examples of the print layer include design print layers (color print layers and the like) such as product names, illustrations, handling precautions, and the like, background print layers formed in a single color such as white, films, and the like. Examples thereof include a protective printing layer provided for protecting the printing layer and a primer printing layer provided for improving the adhesion between the film and the printing layer. Although the said printing layer is not specifically limited, You may be provided only in the single side | surface side of the shrink film of this invention, and may be provided in the both surfaces side of the shrink film of this invention. Moreover, the said printing layer may be provided in the whole surface (surface on the side in which a printing layer is provided) of the shrink film of this invention, and may be provided in part. Furthermore, the printing layer is not particularly limited, but may be a single layer or a multilayer.

  Although the said printing layer is not specifically limited, It is preferable that binder resin is included as an essential component. Furthermore, it may contain additives such as color pigments such as blue, red, yellow, black, white, lubricants, dispersants, antifoaming agents, etc., as necessary. Each of the binder resins may be used alone or in combination of two or more.

  The binder resin is not particularly limited, and for example, a resin used as a binder resin in a known or commonly used printing layer or printing ink can be used. Examples of the binder resin include acrylic resins, urethane resins, polyester resins, polyamide resins, cellulose resins (including nitrocellulose resins), vinyl chloride-vinyl acetate copolymer resins, and the like. The color pigment is not particularly limited, and for example, a color pigment used in a known or conventional printing layer or printing ink can be used. For example, white pigments such as titanium oxide (titanium dioxide), indigo pigments such as copper phthalocyanine blue, carbon black, aluminum flakes, mica (mica), and other colored pigments can be selected and used according to the application. . In addition to the above color pigments, extender pigments such as alumina, calcium carbonate, barium sulfate, silica, and acrylic beads can also be used for the purpose of adjusting gloss.

  Although the thickness of the said printing layer is not specifically limited, For example, 0.1-10 micrometers is preferable, More preferably, it is 0.3-5 micrometers. If the thickness is less than 0.1 μm, it may be difficult to provide a printing layer uniformly, and when partial “fading” occurs, decorativeness is impaired, or printing as designed becomes difficult There is. In addition, if the thickness exceeds 10 μm, a large amount of printing ink is consumed, which increases the cost, makes it difficult to apply uniformly, makes the printed layer brittle and easy to peel off, There is a case where the printing layer hardly follows the thermal shrinkage of the shrink film during the shrink processing.

  1 to 3 are schematic views (partial cross-sectional views) each showing an example of the shrink label of the present invention. The shrink label 3 of the present invention shown in FIG. 1 includes the shrink film 1 of the present invention and a printing layer 2 provided on one side of the shrink film 1 of the present invention. The shrink film 1 of the present invention includes a base layer portion 12 and a surface layer 11 provided on each side of the base layer portion 12. The base layer portion 12 is formed such that the outermost layer (the layer in contact with the surface layer 11) is the A layer 12a, and the A layer 12a and the B layer 12b are alternately laminated in a total of nine layers. In the base layer portion 12, the number of interfaces formed by adjoining (directly laminating) the A layer 12 a and the B layer 12 b is eight. Moreover, the surface layer 11 and the base layer part 12 are laminated | stacked directly, without passing through another layer. Specifically, the surface layer 11 and the A layer 12a that is the outermost layer of the base layer portion 12 are directly laminated without interposing other layers. Further, the B layer 12b is interposed between all the A layers 12a.

  The shrink label 3 of the present invention shown in FIG. 2 includes the shrink film 1 of the present invention and a printing layer 2 provided on one side of the shrink film 1 of the present invention. The shrink film 1 of the present invention includes a base layer portion 12 and a surface layer 11 provided on each side of the base layer portion 12. The shrink label 3 according to the present invention shown in FIG. 2 is a shrink label in which the base layer portion 12 is reverse in the positional relationship between the A layer 12a and the B layer 12b in relation to FIG. That is, the base layer portion 12 is formed such that the outermost layer (the layer in contact with the surface layer 11) is the B layer 12b, and the A layer 12a and the B layer 12b are alternately stacked in total nine layers. In the base layer portion 12, the number of interfaces formed by adjoining (directly laminating) the A layer 12 a and the B layer 12 b is eight. Moreover, the surface layer 11 and the base layer part 12 are laminated | stacked directly, without passing through another layer. Specifically, the surface layer 11 and the B layer 12b which is the outermost layer of the base layer portion 12 are directly laminated without interposing other layers. Further, the B layer 12b is interposed between all the A layers 12a.

  The shrink label 3 of the present invention shown in FIG. 3 includes the shrink film 1 of the present invention and a printed layer 2 provided on one side thereof. The shrink film 1 of the present invention includes a surface layer 11 and a base layer portion 12. The base layer portion 12 is formed by laminating 17 layers of A layers 12a and B layers 12a alternately, with the outermost layer (the layer in contact with the surface layer 11) being an A layer 12a. In the base layer portion 12, the number of interfaces formed by adjoining (directly laminating) the A layer 12a and the B layer 12b is 16. Also in FIG. 3, the surface layer 11 and the base layer portion 12 are directly laminated without interposing other layers, and the surface layer 11 and the A layer 12 a that is the outermost layer of the base layer portion 12 are interposing other layers. There is no direct lamination. Further, the B layer 12b is interposed between all the A layers 12a. In the shrink label 3 of the present invention shown in FIG. 3, the A layer 12a and the B layer 12b may be in the opposite positional relationship.

  Although the thickness (total thickness) of the shrink label of this invention is not specifically limited, 10-100 micrometers is preferable, More preferably, it is 15-60 micrometers, More preferably, it is 20-50 micrometers. When the thickness of the shrink label of the present invention is 10 μm or more, the rigidity of the label is increased, which is preferable.

Density of the shrink label of the present invention is not particularly limited, from the viewpoint of the shrink label and low density, preferably less than 1 g / cm ^3, more preferably less than 0.99 g / cm ^3, more preferably 0.98 g / less than cm ³ . Moreover, the minimum of the said density is 0.92 g / cm < ³ > or more, for example.

  The shrink label of the present invention is, for example, a cylindrical shrink label of a type in which both ends of the label are sealed with a solvent or an adhesive and attached to the container, and one end of the label is attached to the container, and the label is wound After that, it can be used as a wrapping type shrink label in which the other end is overlapped with one end to form a cylinder. Since the shrink film of the present invention has a shrink film excellent in transparency while maintaining heat shrinkability and relaxation deterrence, among these, it is particularly preferably used for a cylindrical shrink label. That is, the shrink label of the present invention is preferably a cylindrical shrink label. Hereinafter, the cylindrical shrink label using the shrink label of the present invention may be referred to as “the cylindrical shrink label of the present invention”.

  An example of a cylindrical shrink label which is a preferred embodiment of the shrink label of the present invention will be described with reference to FIGS. 4 and 5. The cylindrical shrink label 4 of the present invention shown in FIG. 4 is formed into a cylindrical shape by superimposing the other end on the outside of one end of the shrink label of the present invention formed in a rectangular shape. This is a cylindrical body in which a seal part 41 is formed by joining the outer surface of the part with a solvent or an adhesive. The cylindrical shrink label of the present invention includes the shrink film of the present invention, and the shrink film of the present invention is at least oriented in the circumferential direction D of the cylindrical shrink label of the present invention and can be thermally contracted in that direction. In addition, it is preferable that the cylindrical shrink label of this invention is mounted | worn so that the circumferential direction may turn into a main contraction direction.

  FIG. 5 is a cross-sectional view taken along the line AA ′ in FIG. 4, that is, an enlarged view of the main part in the vicinity of the seal part of the tubular shrink label 4 of the present invention. In the seal part 41, both ends of the shrink label are solvent or Bonded with an adhesive 53. Specifically, the shrink label 3 of the present invention is designed and printed in a region excluding the region of a predetermined width from the other end of one surface (surface on the cylindrical inner surface side) of the shrink film 1 of the present invention. The layer 52 is formed, and the background printing layer 51 is formed over substantially the entire region excluding the region of the predetermined width from the end of the other end of the one surface of the shrink film 1 so as to cover the design printing layer 52. Yes. For this reason, in the shrink label 3 of the present invention, the background print layer 51 and the design print layer 52 are not formed in the region having a predetermined width from the end of the other end, and the shrink film 1 of the present invention is exposed, A film exposed surface is formed, and the seal portion 41 includes a film exposed surface formed on the inner surface side of the other end portion of the shrink label 3 of the present invention and an outer surface (film exposed surface) of one end portion with a solvent or an adhesive. 53 are joined. That is, in the seal part 41, it is preferable that the shrink films 1 of the present invention are joined together with a solvent or an adhesive 53. In addition, even if it has a printing layer, such as a background printing layer and a design printing layer, the part which is not joined among the said both ends has an influence on adhesiveness, Therefore It may have a printing layer.

  In the cylindrical shrink label 4 of the present invention in FIG. 5, one end portion extends to a position where the end overlaps the background print layer 51 at the other end, and the background print layer 51 at the one end portion and the other end portion. A region where the layers overlap with each other via the shrink film 1 is formed. For this reason, there is no region where the background print layer 51 does not exist in the thickness direction. The cylindrical shrink label of the present invention may have a structure that overlaps the end of one end and the background printing layer on the other end as shown in FIG. 5, and the end of the one end is exposed to the film on the other end. It extends to the area that overlaps the surface, the end of one end does not extend to the position that overlaps the background print layer on the other end, and the end of the one end and the background print layer on the other end do not overlap Also good.

  Examples of the design printing layer include a layer displaying a trade name, an illustration, handling precautions, and the like. Although it does not specifically limit as said design printing layer, For example, the said printing layer etc. can be used. More specifically, the design print layer is formed by a plurality of print layers having different color pigments so as to have a desired design. Although the thickness of the said design printing layer is not specifically limited, 0.1-8 micrometers is preferable.

  The background print layer is a print layer serving as a background of the design print layer when the tubular shrink label of the present invention is observed from the outside of the tube. Although it does not specifically limit as said background printing layer, For example, the said printing layer etc. can be used. Especially, from a viewpoint used as the background of a design printing layer, background printing layers, such as a white printing layer containing 20-60 weight% of titanium oxide as a coloring pigment, are preferable. Although the thickness of the said background printing layer is not specifically limited, 0.5-10 micrometers is preferable.

  Although the width | variety of the said seal | sticker part is not specifically limited, 1-10 mm is preferable, More preferably, it is 2-4 mm.

  The shrink film of the present invention has a base layer portion and surface layers provided on both surfaces of the base layer portion, the surface layer is a layer containing 50% by weight or more of a polystyrene resin, and the base layer portion is 5 to 65 layers are included, and as the layer, two or more A layers containing a total of 50% by weight of a polystyrene resin and a polyolefin resin are included. Thereby, the shrink label of the present invention is a case where the container or the like to which the shrink label is attached is deformed even though the base layer portion includes a mixed resin layer of a polystyrene resin and a polyolefin resin which are inherently incompatible. However, it has a shrink film excellent in transparency without deteriorating the relaxation deterrence and heat shrinkability that can expand and contract following the deformation of the container.

[Production method of shrink label of the present invention]
The manufacturing method of the shrink label of this invention includes the process of producing the shrink film of this invention at least. In the present specification, the “process for producing the shrink film of the present invention” may be referred to as a “film production process”. The manufacturing method of the shrink label of this invention may further include other processes (processes other than the said film preparation process), such as the process of forming layers other than the shrink film of this invention.

(Film production process)
In the film production step, the shrink film of the present invention can be produced by a conventional method such as melt film formation. Among these, the melt film forming method (particularly, the T-die method) is preferable. As a lamination method, a conventional method such as a co-extrusion method (feed block method, multi-manifold method, etc.), a dry lamination method, or the like can be used. Among these, the coextrusion method is preferable, and the feed block method is preferable. Further, it is preferable that the base layer is multilayered by using a layer multiplier, in particular, a combination of a feed block and a layer multiplier. The layer multiplier is a device that multi-layers film layers. The method of multilayering the film layer with the layer multiplier is not particularly limited, and examples thereof include a method of dividing the film layer in the width direction and then laminating the divided film layer in the thickness direction. In the present specification, the “layer multiplier” may be simply referred to as “multiplier”. The above multiplier can be obtained from, for example, EDI and Crawlen.

  A specific example of the coextrusion method (feed block method) will be described below. For example, the raw material for forming the base layer and the raw material for forming the surface layer are respectively charged into a plurality of extruders each set to a predetermined temperature, and co-extruded from a T-die. At this time, it is preferable to use a combination of a feed block and a multiplier to make the base layer portion multi-layered to have a predetermined laminated structure. Moreover, you may adjust supply_amount | feed_rate using a gear pump as needed. Furthermore, it is preferable to remove foreign substances using a filter because film tearing can be reduced. In addition, although extrusion temperature changes also with the kind of raw material to be used and is not specifically limited, 150-250 degreeC is preferable. A laminated unstretched film (sheet) can be obtained by quenching the coextruded polymer using a cooling drum or the like.

  The film production step is not particularly limited, but in the case of a shrink film in which the base layer portion is formed only from the A layer and the B layer, the raw material constituting the A layer (sometimes referred to as “raw material (a)”), A first stage of melting a raw material constituting the B layer (sometimes referred to as “raw material (b)”) and a raw material constituting the surface layer (sometimes referred to as “raw material (c)”). A second stage in which the raw material (a) and the raw material (b) melted in the first stage are laminated and further laminated to form a laminated body; and formed in the second stage. It is preferable to include at least a third stage of laminating the raw material (c) one layer at a time on both sides of the laminated body. Furthermore, other stages (stages other than the first stage, the second stage, and the third stage) may be included. The other stage is, for example, before the first stage, after the third stage, between the first stage and the second stage, between the second stage and the third stage, etc. It may be provided in the position.

  In the first stage, it is preferable to melt (or melt knead) the raw material (a), the raw material (b), and the raw material (c), respectively, using a known or conventional extruder. For example, the raw material (a), the raw material (b), and the raw material (c) can be charged into three extruders each set at a predetermined temperature, and melted (or melt-kneaded). Although the extrusion temperature of a raw material is not specifically limited, 150-250 degreeC is preferable.

  In the second stage, the laminate obtained by laminating the raw material (a) and the raw material (b) melted in the first stage and further multilayered is not particularly limited. The laminated body formed by sequentially laminating the raw material (a) and the raw material (b), or simultaneously laminating (coextrusion) using a feed block, is formed by further multilayering using a multiplier. The laminated body may be sufficient. The lamination is not particularly limited, but it is preferable to use a combination of a feed block and a multiplier. Each of the above feed blocks and multipliers may use only 1 or 2 or more. In the laminate, the total number of layers formed from the raw material (a) and the number of layers formed from the raw material (b) is preferably 5 to 65 layers, more preferably 5 to 33 layers, still more preferably. Is 9 to 33 layers. The laminate obtained in the second stage forms the base layer portion of the shrink film of the present invention.

  In the second stage, the laminated body obtained by laminating the raw material (a) and the raw material (b), and more specifically, the laminated body, specifically, for example, the raw material (a) melted in the first stage Then, the raw material (b) is extruded using a feed block to produce a laminate (sometimes referred to as “laminated body 1”) having a configuration of [raw material (a) / raw material (b) / raw material (a)]. Then, the laminate 1 is laminated as a unit using a multiplier, and [raw material (a) / raw material (b) / raw material (a) / raw material (a) / raw material (b) / raw material (a ) /... / Raw material (a) / Raw material (b) / Raw material (a)] can be obtained (may be referred to as “laminated body 2”).

  In addition, in the second stage, the laminated body obtained by laminating the raw material (a) and the raw material (b) and further multilayered is specifically the raw material melted in the first stage, for example. (A) and the raw material (b) are extruded using a feed block, and may be referred to as a laminated body having a configuration of [raw material (b) / raw material (a) / raw material (b)] (“laminated body 3”). Then, the laminate 3 as a unit is laminated using a multiplier, and [raw material (b) / raw material (a) / raw material (b) / raw material (b) / raw material (a) / It is also possible to obtain a laminated body (sometimes referred to as “laminated body 4”) having a structure of raw material (b) /... / Raw material (b) / raw material (a) / raw material (b)].

  In addition, in the second stage, the laminated body obtained by laminating the raw material (a) and the raw material (b) and further multilayered is specifically the raw material melted in the first stage, for example. (A) and the raw material (b) are extruded using a feed block to produce a laminate (sometimes referred to as “laminated body 5”) having a configuration of [raw material (a) / raw material (b)], Next, the laminate 5 as a unit is laminated using a multiplier, and [raw material (a) / raw material (b) / raw material (a) / raw material (b) /.../ raw material (a) / A laminate having the structure of the raw material (b)] (sometimes referred to as “laminate 6”) can be obtained. In addition, if the said laminated body 6 is followed from the reverse, [raw material (b) / raw material (a) / raw material (b) / raw material (a) /.../ raw material (b) / raw material (a)]. It is also a laminate having a structure.

  In the third stage, the raw material (c) melted in the first stage is applied to both sides of the laminate (for example, the laminate 2, 4, or 6) formed in the second stage. When laminating, it is preferable to use a feed block. The laminated raw material (c) forms the surface layer of the shrink film of the present invention. By the third step, a multilayer structure in which the raw material (c) melted in the first step is laminated on both sides of the laminate formed in the second step is obtained.

  Although not particularly limited, a laminated unstretched film is obtained by co-extruding the laminated body formed through the first stage, the second stage, and the third stage from a T die and rapidly cooling it using a cooling drum or the like. (Sheet) can be obtained.

  [Raw material (a) / Raw material (b) / Raw material (a) / Raw material (a) / Raw material (b) / Raw material (a) /.../ Raw material (a) / Raw material (b) / Raw material ( a)] has a structure of [A layer / B layer / A layer / A layer / B layer / A layer /... / A layer / B layer / A layer]. Although it should be the base layer portion, in practice, the interface of [A layer / A layer] formed from [raw material (a) / raw material (a)] obtained by laminating the same material of the laminate 2 becomes invisible. Since it becomes one A layer, it becomes a base layer portion having a structure of [A layer / B layer / A layer / B layer /... / A layer / B layer / A layer]. Similarly, the portion of [B layer / B layer] formed from [raw material (b) / raw material (b)] obtained by laminating the same material of the above-described laminate 4 becomes one B layer because the interface becomes invisible. The base layer part derived from the laminate 4 has a structure of [B layer / A layer / B layer / B layer / A layer / B layer /... / B layer / A layer / B layer]. Actually, the base layer portion has a structure of [B layer / A layer / B layer / A layer /... / B layer / A layer / B layer]. In addition, when the surface layer and the outermost layer (resin layer) of the base layer portion are layers made of the same resin composition, the interface becomes invisible, and the surface layer and the outermost layer of the base layer portion are separated. It becomes one layer (surface layer).

  Although it does not specifically limit as said other step, The step of extending | stretching, the step of performing surface treatment, etc. are mentioned. For example, the laminated unstretched film produced in the third stage further has a stage of stretching.

  The stage of stretching (stretching stage) includes biaxial stretching, longitudinal direction or width in the longitudinal direction (film production line direction, also referred to as MD direction) and the width direction (direction orthogonal to the longitudinal direction, also referred to as TD direction). Uniaxial stretching in the direction can be used. As the stretching method, any of a roll method, a tenter method, and a tube method may be used. In the case of biaxial stretching, biaxial stretching may be performed simultaneously, or biaxial stretching may be sequentially performed. More specifically, for example, after stretching at a stretching temperature of 65 to 100 ° C. and a stretching ratio of 1.05 to 1.50 in the longitudinal direction by a roll method, stretching at a stretching temperature of 70 to 100 ° C. in the width direction by a tenter method. The film is stretched at a magnification of 3 to 8 times (preferably 4 to 7 times).

  Examples of the step of performing the surface treatment include a step of performing conventional surface treatments such as corona discharge treatment, primer treatment, and flame treatment on the surface of the shrink film of the present invention.

  In the above film production process, the example in which the base layer portion is formed only from the A layer and the B layer has been described. Can be produced. Moreover, although the said film preparation process showed the example which melt | dissolves and uses three types of raw materials, it is not limited to this, Two types of raw materials (for example, raw material (a) and raw material (b)) are used. A first stage of melting, and a second stage of stacking two kinds of raw materials (for example, the raw material (a) and the raw material (b)) that are melted in the first stage to form a laminate. In this case, the third stage is not provided, and the outermost layer of the second-stage laminate is the surface layer.

(Other processes)
Although it does not specifically limit in the manufacturing method of the shrink label of this invention, You may have the process of providing a printing layer, the process of providing a protective layer, etc. as processes (other processes) other than a film preparation process.

  In the step of providing the printing layer, the printing layer is formed by performing one or more printing steps in which printing ink is applied and solidified by drying or the like on at least one surface of the shrink film of the present invention. For example, one or more printing steps can be performed to form a design printing layer, and then one or more printing steps can be performed to form a background printing layer. For the step of providing the above-mentioned printing layer, a well-known and commonly used printing method can be used, and among them, a gravure printing method or a flexographic printing method is preferable.

  The printing ink is produced, for example, by mixing the binder resin, the color pigment, a solvent, and other additives as necessary. Mixing can be carried out by a known or conventional mixing method, and is not particularly limited. For example, a mixer such as a paint shaker, butterfly mixer, planetary mixer, pony mixer, dissolver, tank mixer, homomixer, homodisper, A mill such as a roll mill, a sand mill, a ball mill, a bead mill, or a line mill, or a mixing device such as a kneader is used. The mixing time (retention time) during mixing is not particularly limited, but is preferably 10 to 120 minutes. The obtained printing ink may be used after being filtered, if necessary. Each of the above components (binder resin, color pigment, solvent, and other additives) may be used alone or in combination of two or more.

  As said solvent (solvent), the organic solvent etc. which are normally used for printing ink can be used. Examples of the solvent include esters such as acetates (ethyl acetate, propyl acetate, butyl acetate, etc.); alcohols such as methanol, ethanol, isopropyl alcohol, propanol, and butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; toluene, xylene Aromatic hydrocarbons such as hexane, octane, etc .; Alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; Glycols such as ethylene glycol and propylene glycol; Ethylene glycol monopropyl ether, Propylene glycol monomethyl ether, Propylene Glycol ethers such as glycol monobutyl ether; Glycol ether esters such as propylene glycol monomethyl ether acetate It is. The solvent can be removed by drying after applying the printing ink to the shrink film of the present invention. The solvent (solvent) also includes the meaning of “dispersion medium”.

(Manufacturing method of cylindrical shrink label)
Although the manufacturing method of the cylindrical shrink label of this invention is not specifically limited, For example, it is as follows. A long length of the shrink film of the present invention is optionally provided with a printing layer and the like, then slit to a predetermined width, and a plurality of shrink labels of the present invention are continuous in the long direction (longitudinal direction). Get the body. This long label is formed in a cylindrical shape by overlapping so that the main shrinkage direction (that is, the main shrinkage direction of the shrink film of the present invention) is the circumferential direction, and the other end is outside the one end. Then, the overlapped portion is sealed in a band shape with a predetermined width, and both end portions are joined together to obtain a long cylindrical label continuous body (long cylindrical shrink label). By cutting this long cylindrical shrink label in the width direction so that the longitudinal direction has a predetermined length, one cylindrical shrink label having a predetermined length in the height direction (the cylindrical shrink label of the present invention) ) Can be obtained.

  In addition, when providing the perforation for label cutting to a cylindrical shrink label, the perforation of predetermined length and pitch is formed in the vertical direction (direction orthogonal to the circumferential direction). The perforation can be applied by a conventional method (for example, a method of pressing a disk-shaped blade having a cut portion and a non-cut portion repeatedly formed around it, a method using a laser, or the like). The step of perforating can be selected as appropriate after the step of providing the printed layer or before or after the step of processing into a cylindrical shape.

[Container with label]
Although the shrink label of this invention is not specifically limited, It mounts | wears with a container and is used as a labeled container. In addition, the shrink label of this invention may be used for adherends other than a container. For example, the shrink label of the present invention (particularly, the cylindrical shrink label) is placed around the container so that the shrink label of the present invention is in a cylindrical shape, and attached to the container by heat shrinking. A container (a labeled container having the shrink label of the present invention) is obtained. Examples of the containers include soft drink bottles such as PET bottles, milk bottles for home delivery, food containers such as seasonings, bottles for alcoholic beverages, pharmaceutical containers, containers for chemical products such as detergents and sprays, and toiletries. Containers, cup noodle containers and the like are included. Although it does not specifically limit as a shape of the said container, For example, various shapes, such as bottle types, such as cylindrical shape and a square shape, and a cup type, are mentioned. The material of the container is not particularly limited, and examples thereof include plastic such as PET, glass, and metal. Since the shrink label of the present invention has relaxation deterrence, it is a container for carbonated beverages that shrinks and deforms when the internal pressure is reduced when opened, and a frozen product that shrinks and deforms when the frozen contents are dissolved. It is particularly preferable to use the container for contents such as a container that deforms, such as a tube container that dents and deforms when squeezed to take out the contents.

  The labeled container can be produced, for example, by externally fitting a cylindrical shrink label to a predetermined container, and then thermally shrinking the cylindrical shrink label by heat treatment so as to follow and closely adhere to the container (shrink processing). Examples of the heat treatment method include a method of passing through a hot air tunnel or a steam tunnel, a method of heating with radiant heat such as infrared rays, and the like. In particular, a method of treating with steam at 80 to 100 ° C. (passing through a heating tunnel filled with steam and steam) is preferable. Moreover, 101-140 degreeC dry steam can also be used. Although the said heat processing is not specifically limited, It is preferable to implement in the temperature range from which the temperature of a shrink film will be 85-100 degreeC (especially 90-97 degreeC). Since the shrink film of the present invention can be heated at a particularly high temperature, it can be used for containers that require high heat shrinkability. Moreover, the processing time of heat processing has preferable 4 to 20 second from a viewpoint of productivity and economical efficiency.

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.
In Table 1, composition of surface layer raw material (raw material (c)), A layer raw material (raw material (a)), B layer raw material (raw material (b)), shrink made in Examples and Comparative Examples The composition and evaluation results of the film and shrink label are shown.

Example 1
(material)
As the raw material constituting the A layer (raw material for the A layer), polypropylene resin A (manufactured by Nippon Polypro Co., Ltd., trade name “Wintech WFX6”) is 26.3% by weight, polyethylene resin A (Nippon Polyethylene Co., Ltd.) ), Trade name “Kernel KF260T”) 1.9% by weight, petroleum resin A (Arakawa Chemical Industries, trade name “Arcon P-125”) 9.4% by weight, polystyrene resin A ( 11.0% by weight of Stylolusion, trade name “Styrolux S”, content of structural unit derived from butadiene: 12% by weight, polystyrene resin B (StyloLusion, trade name “Styrolox T”) The content of the structural unit derived from butadiene was 25% by weight).
As the raw material constituting the B layer (B layer raw material), 70% by weight of the polypropylene resin A, 5% by weight of the polyethylene resin A, and 25% by weight of the petroleum resin A were used.
As raw materials constituting the surface layer (surface layer raw material), 80% by weight of polystyrene resin A and 20% by weight of polystyrene resin B were used.

(Shrink film)
The raw material for the A layer was charged into the extruder x heated to 220 ° C, the raw material for the B layer was charged into the extruder y heated to 220 ° C, and the raw material for the surface layer was charged into the extruder z heated to 220 ° C. Melt extrusion was performed using the above three extruders. Using a laminating apparatus that combines a molten A-layer raw material and a molten B-layer raw material with a two-layer / three-layer feed block and a four-part multiplier, the A-layer raw material / B-layer Dividing, merging and laminating 2 types and 3 layers of raw material / A layer raw material as one repeating unit, laminated body (I) (4 types of the above described 2 types and 3 layers are laminated (4 repetitions)) The melted raw material for the surface layer was merged and laminated on both sides of the laminate (I) using a feed block to obtain a laminate (II). Furthermore, after extruding the laminate (II) from a T-die, the laminate (II) was rapidly cooled on a casting drum cooled to 25 ° C. to obtain a laminated unstretched film in which surface layers were respectively provided on both sides of the base layer portion. .
Next, the laminated unstretched film is stretched 5 times at 85 ° C. in the width direction to be stretched mainly in the width direction, and a stretched film (shrink film) having heat shrinkability in that direction. Got.
The shrink film has an 11-layer configuration of [surface layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / surface layer]. In the above-mentioned shrink film, the base layer portion is 12 layers because the repeating unit of 2 types, 3 layers configuration is laminated with the repetition number 4, but the portion where the raw materials for the A layer overlap is actually the interface between the layers. It disappears and overlaps into a single layer. For this reason, the base layer portion has a nine-layer configuration of [A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer], and the outermost layer of the base layer portion is It is an A layer, and a B layer is interposed between all A layers. The number of interfaces [A / B] is 8 in the base layer portion.

(Cylinder shrink label)
A part to be used as a seal part after forming a design print layer on one side of the shrink film using a process color printing ink while conveying the long body of the shrink film obtained above in the longitudinal direction by a gravure printing machine The printing layer having a thickness of about 3 μm was formed by forming a background printing layer using a white printing ink, and a long shrink label was obtained.
Next, after slitting the elongated body of the shrink label to have a predetermined width and forming a perforation, the one end and the other end are overlapped to form a cylinder so that the width direction is the circumferential direction, The shrink film surfaces of the one end and the other end were sealed with a solvent to obtain a tubular long body of a shrink label. Furthermore, the cylindrical long body (label continuous body) of the shrink label was cut into individual label sizes to obtain a cylindrical shrink label.

(Container with label)
Next, the tubular shrink label was externally fitted to a 500 ml polyethylene narrow mouth container, and then passed through a 90 ° C. steam tunnel to thermally shrink the tubular shrink label to obtain a labeled container.

Example 2
(material)
The A layer raw material, the B layer raw material, and the surface layer raw material used in Example 1 were used as the A layer raw material, the B layer raw material, and the surface layer raw material.

(Shrink film)
The raw material for the A layer was charged into the extruder x heated to 220 ° C, the raw material for the B layer was charged into the extruder y heated to 220 ° C, and the raw material for the surface layer was charged into the extruder z heated to 220 ° C. Melt extrusion was performed using the above three extruders. Using the laminating apparatus that combines the melted raw material for the A layer and the molten raw material for the B layer with a two-layer / three-layer type feed block and an 8-split multiplier, the material for the A layer / for the B layer Dividing, merging and laminating 2 types and 3 layers of raw material / A layer raw material as one repeating unit, laminated body (III) (8 types of 2 types and 3 layers are stacked (repetition number 8)) Then, the melted raw material for the surface layer was joined and laminated on both sides of the laminate (III) using a feed block to obtain a laminate (IV). Furthermore, after extruding the laminate (IV) from a T-die, it was rapidly cooled on a casting drum cooled to 25 ° C. to obtain a laminated unstretched film in which surface layers were provided on both sides of the base layer portion, respectively. .
Next, the laminated unstretched film is stretched 5 times at 85 ° C. in the width direction to be stretched mainly in the width direction, and a stretched film (shrink film) having heat shrinkability in that direction. Got.
The shrink film is [surface layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer. / A layer / B layer / A layer / surface layer]. In the above-mentioned shrink film, the base layer part is 24 layers because the repeating unit of 2 types, 3 layers structure is laminated with a repetition number of 8, but the part where the raw materials for the A layer overlap is actually the interface between the layers. It disappears and overlaps into a single layer. For this reason, the base layer portion is [A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer]. The outermost layer of the base layer portion is the A layer, and the B layer is interposed between all the A layers. The number of interfaces [A / B] is 16 in the base layer portion.

(Cylinder shrink label, labeled container)
A cylindrical shrink label and a labeled container were obtained in the same manner as in Example 1 using the shrink film obtained above.

Example 3
(material)
As raw materials for layer A, polypropylene resin A is 26.3% by weight, polyethylene resin A is 1.9% by weight, petroleum resin A is 9.4% by weight, polystyrene resin A is 18.7% by weight, polystyrene The resin B was used at 43.8% by weight.
The B layer material used in Example 1 was used as the B layer material.
As the raw material for the surface layer, 30% by weight of polystyrene resin A and 70% by weight of polystyrene resin B were used.

(Shrink film, cylindrical shrink label, labeled container)
A shrink film, a cylindrical shrink label, and a container with a label were obtained in the same manner as in Example 1 except that the A layer raw material, the B layer raw material, and the surface layer raw material were used. The shrink film has an 11-layer configuration of [surface layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / surface layer]. In the above-mentioned shrink film, the base layer portion is 12 layers because the repeating units of 2 types and 3 layers are laminated at a repetition number of 4, but in reality, the portion where the raw materials for layer A overlap each other cannot see the interface between the layers. , Overlap to form one layer. For this reason, the base layer portion has a nine-layer configuration of [A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer], and the outermost layer of the base layer portion is It is an A layer, and a B layer is interposed between all A layers. The number of interfaces [A / B] is 8 in the base layer portion.

Example 4
(material)
As raw materials for the A layer, 37.5% by weight of polypropylene resin B (trade name “Vistamaxx 3980” manufactured by ExxonMobil Chemical Co., Ltd.), 11.0% by weight of polystyrene resin A, and 51.5% of polystyrene resin B % By weight was used.
As a raw material for the B layer, 100% by weight of polypropylene resin B was used.
The surface layer material used in Example 1 was used as the surface layer material.

(Shrink film, cylindrical shrink label, labeled container)
A shrink film, a cylindrical shrink label, and a container with a label were obtained in the same manner as in Example 1 except that the A layer raw material, the B layer raw material, and the surface layer raw material were used. The shrink film has an 11-layer configuration of [surface layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer / surface layer]. In the above-mentioned shrink film, the base layer portion is 12 layers because the repeating units of 2 types and 3 layers are laminated at a repetition number of 4, but in reality, the portion where the raw materials for layer A overlap each other cannot see the interface between the layers. , Overlap to form one layer. For this reason, the base layer portion has a nine-layer configuration of [A layer / B layer / A layer / B layer / A layer / B layer / A layer / B layer / A layer], and the outermost layer of the base layer portion is It is an A layer, and a B layer is interposed between all A layers. The number of interfaces [A / B] is 8 in the base layer portion.

Comparative Example 1
(material)
The A layer raw material, the B layer raw material, and the surface layer raw material used in Example 1 were used as the A layer raw material, the B layer raw material, and the surface layer raw material.

(Shrink film)
The raw material for the A layer was charged into the extruder x heated to 220 ° C, the raw material for the B layer was charged into the extruder y heated to 220 ° C, and the raw material for the surface layer was charged into the extruder z heated to 220 ° C. Melt extrusion was performed using the above three extruders. 2 types 3 layers composition of A layer raw material / B layer raw material / A layer raw material using a feed block of a 2 type 3 layer confluence system for molten A layer raw material and molten B layer raw material The laminate (V) was prepared, and the melted raw material for the surface layer was joined and laminated on both sides of the laminate (V) using a feed block to obtain a laminate (VI). Furthermore, after the laminate (VI) was extruded from a T-die, it was rapidly cooled on a casting drum cooled to 25 ° C. to obtain a laminated unstretched film in which surface layers were provided on both sides of the base layer portion. .
Next, the laminated unstretched film is stretched 5 times at 85 ° C. in the width direction to be stretched mainly in the width direction, and a stretched film (shrink film) having heat shrinkability in that direction. Got.

  The shrink film has a five-layer configuration of [surface layer / A layer / B layer / A layer / surface layer]. Therefore, in the shrink film, the base layer portion has a three-layer configuration of [A layer / B layer / A layer], and the outermost layer of the base layer portion is the A layer. The number of interfaces [A / B] is 2 in the base layer portion.

(Cylinder shrink label, labeled container)
A cylindrical shrink label and a labeled container were obtained in the same manner as in Example 1 using the shrink film obtained above.

(Evaluation)
The following evaluation was performed about the shrink label obtained by the Example and the comparative example. The evaluation results are shown in Table 1.

(1) Thermal shrinkage (90 ° C for 10 seconds)
From the shrink film (before shrink processing) obtained in the examples and comparative examples, a rectangular shape of 120 mm (width direction; main shrinkage direction, marked line interval 10 mm) × 5 mm (longitudinal direction; perpendicular direction to the main shrinkage direction) Sample pieces were prepared.
The sample piece was heat-treated for 10 seconds (under no load) in warm water at 90 ° C., the difference between the marked line intervals before and after the heat treatment was read, and the heat shrinkage rate was calculated by the following formula.
Shrinkage rate (%) = (L ₀ −L ₁ ) / L ₀ × 100
L ₀ : Size of sample piece before heat treatment (main shrinkage direction)
L ₁ : Sample dimensions after heat treatment (same direction as L ₀ )

(2) Transparency (haze value)
A label sample having a size of 100 mm (longitudinal direction; perpendicular direction to the main shrinkage direction) × 150 mm (width direction; main shrinkage direction) was cut out from the shrink labels produced in the examples and comparative examples to obtain a measurement sample. It was.
Using the “Haze-Guard II” manufactured by Toyo Seiki Seisakusho Co., Ltd., the haze value of the above measurement sample was measured in accordance with JIS K 7136.

  As can be seen from Table 1, the shrink labels (Examples 1 to 3) of the present invention had a sufficient heat shrinkage and excellent transparency of the shrink film. On the other hand, a shrink label in which the base layer portion contains a polystyrene resin and a polyolefin resin, and the total content of the polystyrene resin and the polyolefin resin is 50% by weight or more (layer A) is not more than two layers. (Comparative Example 1) had a sufficient heat shrinkage ratio, but the transparency of the shrink film was low. It should be noted that the labeled containers produced in the examples and comparative examples are all relaxed without pressing the body surface of the labeled container by hand and deforming the container 10 times so that the label is not so relaxed. The property was good.

DESCRIPTION OF SYMBOLS 1 Shrink film of this invention 11 Surface layer 12 Base layer part 12a A layer 12b B layer 2 Print layer 3 Shrink label of this invention 4 Cylindrical shrink label 41 Seal part D Circumferential direction 51 Background printing layer 52 Design printing layer 53 Solvent or adhesive

Claims (5)

A shrink label having a shrink film,
The shrink film has a base layer portion and surface layers provided on both sides of the base layer portion,
The surface layer contains 50% by weight or more of a polystyrene-based resin,
The base layer portion includes 5 to 65 layers, and contains a polystyrene resin and a polyolefin resin as a layer in the base layer portion, and the total content of the polystyrene resin and the polyolefin resin is 50 wt. The shrink label characterized by containing 2 or more layers (A layer) which are% or more.   The shrink label according to claim 1, wherein the surface layer and the outermost layer of the base layer portion are directly laminated, and the outermost layer of the base layer portion is the A layer.   The shrink label according to claim 1 or 2, wherein the base layer portion contains at least one layer (B layer) containing 50% by weight or more of a polyolefin resin as a layer in the base layer portion.   The shrink label according to claim 3, wherein the base layer portion has a structure in which the A layer and the B layer are directly laminated.   The shrink label according to any one of claims 1 to 4, wherein a thickness per one of the A layers is 0.2 to 8 µm.

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