JP6936569B2 - Shrink label - Google Patents

Description

The present invention relates to shrink labels.

Currently, plastic bottles such as PET bottles and metal bottles such as bottle cans are widely used as beverage containers for tea and soft drinks. These containers are often fitted with plastic labels for labeling, decoration, and functionality. Examples of such a plastic label include a shrink label in which a printing layer is provided on a shrink film (heat shrinkable film) because of its merits such as decorativeness, processability (followability to a container), and a large display area. Widely used.

The shrink film used for the shrink label contains, for example, an amorphous aromatic polyester resin as a main component, and 0.5 to 20 parts by weight of a thermoplastic agent with respect to 100 parts by weight of the amorphous aromatic polyester resin. A surface layer (A layer) composed of a resin composition contained therein, and a central layer (B layer) composed of a resin composition containing a styrene-conjugated diene copolymer and / or a hydrogenated product thereof as a main component. However, there is known a shrink film characterized by having at least a three-layer laminated structure in which an A layer / a B layer / an A layer are laminated in this order (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2009-178887

In recent years, shrink labels have been required to be thinner from the viewpoint of cost reduction and resource saving. However, as the shrink film having a structure in which different materials are laminated as described in Patent Document 1, the interlayer strength is lowered as the wall thickness is reduced, and delamination may easily occur. Further, even if delamination does not occur in the shrink film, when the print layer is provided on the shrink film, the solvent contained in the printing ink forming the print layer erodes between the layers of the laminated dissimilar materials. However, delamination sometimes occurred. For example, when a printing ink containing a low-volatile solvent or a printing ink containing a large amount of ester-based solvent is used as the printing ink, or when a plurality of printing layers are overcoated to form a thick ink, the printing ink is like white ink. When a print layer containing a large amount of pigment such as titanium oxide was formed in the print layer, delamination was likely to occur.

Therefore, an object of the present invention is to provide a shrink label in which delamination is unlikely to occur even though a print layer is provided.

That is, the present invention is a shrink label having a shrink film and a printing layer provided on at least one surface of the shrink film, and the shrink film is provided on both sides of the base layer portion and the base layer portion. The surface layer provided on both sides thereof is a layer having a polyester resin content of 50% by weight or more, and the base layer portion contains 3 to 65 layers and is the base layer. As the layers in the film, a layer (layer A) having a polystyrene resin content of 50% by weight or more, a polyester resin content of more than 30% by weight and 92% by weight or less, and a styrene-based elastomer content. It has at least a layer (B layer) having a content of 3 to 30% by weight and a polystyrene resin other than the styrene-based elastomer in an amount of 5% by weight or more and less than 67% by weight, and at least one of the outermost layers of the base layer portion has. Provided is a shrink label which is a B layer and has at least a structure in which a surface layer provided with the printing layer and a B layer which is the outermost layer of the base layer portion are directly laminated.

The thickness of the surface layer provided with the printing layer is preferably 5 to 15 μm.

The base layer portion preferably contains 5 to 65 layers.

The styrene-based elastomer in the B layer is preferably a styrene-diene-based copolymer elastomer.

The printed layer preferably contains a layer having a titanium oxide content of 30 to 85% by weight and a thickness of 0.5 μm or more.

Since the shrink label of the present invention has the above structure, delamination is unlikely to occur even though the print layer is provided.

It is the schematic (partial sectional view) which shows an example of the shrink label of this invention. It is the schematic (partial sectional view) 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. It is a schematic diagram (the main part enlarged view of the IV-IV'cross section of FIG. 3) which shows an example of the cylindrical shrink label which is one Embodiment of the shrink label of this invention.

The shrink label of the present invention has a shrink film and a printing layer provided on at least one side of the 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 the present invention may include a layer other than the shrink film of the present invention and the above-mentioned printing layer as long as the effect of the present invention is not impaired.

[Shrink film]
The shrink film of the present invention has surface layers on both sides of the base layer portion. That is, the shrink film of the present invention includes a base layer portion and surface layers provided on both side surfaces 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. However, the surface layer provided with at least one of the above printing layers and the base layer portion are directly laminated. The surface layers in the shrink film of the present invention may be the same layer or different layers (layers having different resin compositions and layer thicknesses). The shrink film of the present invention may contain a layer other than the base layer portion and the surface layer as long as the object of the present invention is not impaired. The layers other than the base layer and the surface layer are not particularly limited, and examples thereof include an antistatic layer and an anchor coat layer. If necessary, the surface of the shrink film of the present invention may be subjected to conventional surface treatments such as corona discharge treatment, primer treatment, and frame treatment.

<Surface layer>
The surface layer (that is, the surface layers provided on both side surfaces of the base layer portion) in the shrink film of the present invention is a layer having a polyester resin content of 50% by weight or more. By having the above-mentioned surface layer, the shrink film of the present invention can improve the rigidity and strengthen the waist. In addition, the heat shrinkage rate is improved. It also has excellent transparency and solvent resistance.

The surface layer contains a polyester resin as an essential component. As the polyester resin, only one kind may be used, or two or more kinds may be used. The surface layer is not particularly limited, but may contain a resin other than the polyester-based resin.

The polyester-based resin includes, for example, a polyester composed of a dicarboxylic acid component and a diol component as essential components (that is, a polyester containing at least a structural unit derived from a dicarboxylic acid (structural unit) and a structural unit derived from a diol. ), Polylactic acid-based polymer, polyester-based elastomer and the like. The main polyesters containing at least a structural unit derived from a dicarboxylic acid and a structural unit derived from a diol include a polymer, a copolymer, or a mixture thereof by a condensation reaction of a dicarboxylic acid and a diol. As the polyester resin, a soft polyester resin such as polyethylene terephthalate to which a plasticizer is added may be used.

Examples of the dicarboxylic acid (dicarboxylic acid component) include terephthalic acid, isophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 5-t-butylisophthalic acid, 4,4'-biphenyldicarboxylic acid, and trans-3. , 3'-stillbenzicarboxylic acid, trans-4,4'-stillbenzicarboxylic acid, 4,4'-dibenzyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,3-naphthalene Dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 2,2,6,6-tetramethylbiphenyl-4,4'-dicarboxylic acid, 1,1,3-trimethyl-3-phenyl Inden-4,5-dicarboxylic acid, 1,2-diphenoxyetane-4,4'-dicarboxylic acid, diphenyletherdicarboxylic acid, 2,5-anthracenedicarboxylic acid, 2,5-pyridinedicarboxylic acid, and their substitutes. Aromatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, etc. Aliphatic dicarboxylic acids such as pentadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonadecandioic acid, icosandioic acid, docosandioic acid, 1,12-dodecandioic acid, and their substitutes; 1,3-cyclopentane Dicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-decahydronaphthalenedicarboxylic acid, 1,5-decahydronaphthalenedicarboxylic acid, 2,6 -Decahydronaphthalenedicarboxylic acids, alicyclic dicarboxylic acids such as their substitutes, and the like can be mentioned. As the dicarboxylic acid, only one kind may be used, or two or more kinds may be used.

Examples of the diol (diol component) include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. , 2,2-Dimethyl-1,3-propanediol (neopentyl glycol), 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 2,2-diethyl-1,3 -Propanediol, 1,8-octanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2,4-dimethyl-1,3-hexanediol, 1,10-decanediol, Aliphatic diols such as polyethylene glycol and polypropylene glycol; 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3- Alicyclic diols such as cyclobutanediol; ethylene oxide adducts of bisphenol compounds such as 2,2-bis (4-β-hydroxyethoxyphenyl) propane and bis (4-β-hydroxyethoxyphenyl) sulfone, xylylene glycol and the like. Aromatic diols and the like can be mentioned. As the above diol, only one kind may be used, or two or more kinds may be used.

In addition to the above, the polyester-based resin includes oxycarboxylic acids such as p-oxybenzoic acid and p-oxyethoxybenzoic acid; monocarboxylic acids such as benzoic acid and benzoylbenzoic acid; and polyvalent carboxylic acids such as trimellitic acid. It may contain a structural unit derived from a monohydric alcohol such as polyalkylene glycol monomethyl ether; or a polyhydric alcohol such as glycerin, pentaerythritol, or trimethylolpropane.

Among them, the aromatic polyester resin is preferable as the polyester resin from the viewpoint of shrinkage characteristics, rigidity, mechanical strength and the like. The aromatic polyester-based resin contains 50 mol% or more (preferably 70 mol% or more) of the total dicarboxylic acid component and / or 50 mol% or more (preferably 70 mol% or more) of the total diol component. Is a polyester-based resin in which 70 mol% or more) is an aromatic diol. Further, an aromatic polyester resin which is a polymer, a copolymer, or a mixture thereof by a condensation reaction between a dicarboxylic acid containing an aromatic dicarboxylic acid and a diol containing an aliphatic diol is preferable.

The aromatic polyester-based resin is made from the viewpoint of making the polyester-based resin amorphous so that delamination between the surface layer and the base layer portion is less likely to occur, and from the viewpoints of stretching characteristics, shrinkage characteristics, and rigidity. A modified aromatic polyester-based resin containing a modifying component (copolymerization component) rather than being composed of a single repeating unit is preferable. The modified aromatic polyester-based resin includes, for example, a modified aromatic polyester-based resin in which at least one of a dicarboxylic acid component and a diol component is composed of two or more components, that is, a modified aromatic polyester-based resin is contained in addition to the main component. Resin is preferred. In other words, the aromatic polyester-based resin is preferably a modified aromatic polyester-based resin containing a structural unit derived from at least two or more types of dicarboxylic acids and / or a structural unit derived from at least two or more types of diols.

Among the above, the modified aromatic polyester resin is a part of the dicarboxylic acid component and / or the diol component in polyethylene terephthalate (PET) using terephthalic acid as the dicarboxylic acid component and ethylene glycol (EG) as the diol component. A modified PET in which is replaced with a modified component (that is, another dicarboxylic acid component and / or another diol component) is preferably exemplified.

Examples of the dicarboxylic acid component used as the modifying component (copolymerization component) of the modified aromatic polyester resin (particularly modified PET) include cyclohexanedicarboxylic acid, adipic acid, isophthalic acid and the like. Of these, isophthalic acid is preferable. Examples of the diol component used as the denaturing component include 2,2-dialkyl-1,3-propanediol such as 1,4-cyclohexanedimethanol (CHDM) and neopentyl glycol (NPG), and diethylene glycol and the like. Of these, CHDM, 2,2-dialkyl-1,3-propanediol (particularly NPG) is preferable. The alkyl group in the above 2,2-dialkyl-1,3-propanediol is preferably an alkyl group having 1 to 6 carbon atoms, and the two alkyl groups may be the same alkyl group or different. It may be an alkyl group.

The aromatic polyester-based resin is not particularly limited, but specifically, PET using terephthalic acid as the dicarboxylic acid component and EG as the diol component from the viewpoint of heat shrinkage (shrinkage characteristics); dicarboxylic acid. A modified aromatic polyester resin using terephthalic acid as a component, ethylene glycol as a main component (for example, the most abundant diol component), and CHDM as a copolymerization component (sometimes referred to as "CHDM copolymerized PET"). ); A modified aromatic polyester resin using terephthalic acid as the dicarboxylic acid component, ethylene glycol as the main component as the diol component, and 2,2-dialkyl-1,3-propanediol as the copolymerization component ("2,2". -Dialkyl-1,3-propanediol copolymerized PET ") is preferable. Among the above 2,2-dialkyl-1,3-propanediol copolymerized PETs, in particular, a modified fragrance using terephthalic acid as the dicarboxylic acid component, ethylene glycol as the main component as the diol component, and NPG as the copolymerization component. Group polyester resins (sometimes referred to as "NPG copolymerized PET") are preferred. The aromatic polyester-based resin is particularly preferably CHDM copolymerized PET and / or 2,2-dialkyl-1,3-propanediol copolymerized PET, and more preferably CHDM copolymerized PET and / or NPG copolymerized PET. , Most preferably CHDM copolymerized PET. In the above-mentioned CHDM copolymerized PET and 2,2-dialkyl-1,3-propanediol copolymerized PET, copolymerization components other than CHDM and 2,2-dialkyl-1,3-propanediol are used, respectively. For example, isophthalic acid or diethylene glycol may be further copolymerized.

In the above-mentioned modified aromatic polyester resin, the copolymerization ratio of the copolymerization component (modification component) [the ratio (ratio) of the copolymerization dicarboxylic acid component to the total dicarboxylic acid component, or the ratio of the copolymerization diol component to the total diol component ( The ratio)] is not particularly limited, but is preferably 10 mol% or more (for example, 10 to 40 mol%), more preferably 15 mol%, from the viewpoint of optimizing the thermal deformation behavior of the layer and further reducing delamination. The above (for example, 15 to 40 mol%). Among them, for example, in the case of CHDM copolymerized PET, the ratio of CHDM is preferably 10 mol% or more (EG is 90 mol% or less), and more preferably 12 mol% or more (EG is 88 mol% or less) in the total diol component. ), More preferably 15 mol% or more (EG is 85 mol% or less), 20 mol% or more (EG is 80 mol% or less), and 25 mol% or more (EG is 75 mol% or less). .. The upper limit of the proportion of CHDM is preferably 40 mol% or less (EG of 60 mol% or more), more preferably 35 mol% or less (EG of 65 mol% or more), and further preferably 30 mol of the total diol components. % Or less (EG is 70 mol% or more), particularly preferably 25 mol% or less (EG is 75 mol% or more). In the case of 2,2-dialkyl-1,3-propanediol copolymerized PET, the ratio of 2,2-dialkyl-1,3-propanediol (in the case of NPG copolymerized PET, the ratio of NPG) is the total. Of the diol components, 10 mol% or more (EG is 90 mol% or less) is preferable, and 15 mol% or more (EG is 85 mol% or less) is more preferable. The upper limit of the proportion of NPG is preferably 40 mol% or less (EG is 60 mol% or more), and more preferably 30 mol% or less (EG is 70 mol% or more) in the total diol component. Further, a part of the EG component (preferably 1 to 30 mol%, more preferably 1 to 10 mol% in the total diol component) may be replaced with diethylene glycol.

The aromatic polyester-based resin is preferably a substantially amorphous aromatic polyester-based resin, and more preferably an aromatic polyester-based resin which is an amorphous saturated polyester-based resin. Although not particularly limited, the aromatic polyester-based resin can be made substantially amorphous by, for example, because it becomes difficult to crystallize by being modified as described above. By making the aromatic polyester resin amorphous, extrusion at a relatively low temperature becomes possible. As a result, the layer formability of the surface layer during extrusion is improved, so that delamination is less likely to occur between the surface layer and the base layer portion, and the shrinkage property of the shrink label of the present invention is improved. ..

The crystallinity of the polyester resin measured by the differential scanning calorimetry (DSC) method (measured at a heating rate of 10 ° C./min) is preferably 15% or less, more preferably 10% or less. Further, it is most preferable that the polyester resin has almost no melting point (melting peak) when measured by the DSC method (that is, one having a crystallinity of 0%). The crystallinity can be calculated from the value of the heat of fusion of crystals obtained by DSC measurement, using a sample with a clear crystallinity measured by an X-ray method or the like as a standard. The heat of fusion of crystals is, for example, using a DSC (differential scanning calorimetry) device manufactured by Seiko Instruments Inc., with a sample amount of 10 mg and a temperature rise rate of 10 ° C./min, nitrogen sealing is performed, and the temperature rises to the melting point or higher once. It can be obtained from the area of the melting peak when the temperature is raised again after warming and lowering to room temperature. The crystallinity is preferably measured from a single resin, but when measured in a mixed state, the melting peak of the mixed resin is subtracted from the melting peak of the target aromatic polyester resin. Just ask.

The weight average molecular weight (Mw) of the polyester resin is preferably 15,000 to 100,000, more preferably 15,000 to 90,000, still more preferably 30,000 to, from the viewpoint of melting behavior and shrinkage behavior. It is 90,000, particularly preferably 30,000 to 80,000. In the case of 2,2-dialkyl-1,3-propanediol copolymerized PET, 50,000 to 70,000 is particularly preferable. In the present specification, the weight average molecular weight (Mw) is not particularly limited, but can be measured by, for example, GPC using polystyrene as a standard substance.

The glass transition temperature (Tg) of the polyester resin is preferably 60 to 80 ° C., more preferably 60 to 75 ° C. from the viewpoint of stretching characteristics and shrinkage characteristics. The Tg can be controlled by the types of dicarboxylic acids and diols constituting the polyester resin and the copolymerization ratio of the copolymerization component (modification component) used for modification.

In the present specification, the glass transition temperature (Tg) of the resin can be measured by DSC (Differential Scanning Calorimetry) in accordance with JIS K 7121, for example. The DSC measurement is not particularly limited, but can be performed, for example, using a differential scanning calorimeter "DSC6200" manufactured by Seiko Instruments Inc. at a heating rate of 10 ° C./min.

As the polyester resin, commercially available products may be used, for example, "EMBRACE 21214" and "EMBRACE LV" (hereinafter, CHDM copolymer PET) manufactured by Eastman Chemical (Eastman Chemical), and Bell Polyester Products Co., Ltd. "Bellpet MGG200" (2,2-dialkyl-1,3-propanediol copolymer PET), "Bellpet E02" (NPG copolymer PET) manufactured by Bell Polyester Products Co., Ltd., "Sky Green" manufactured by SK Chemical Co., Ltd. Etc. are available on the market.

The polylactic acid-based polymer means a polymer containing lactic acid (D-lactic acid, L-lactic acid, DL-lactic acid, or a mixture thereof) as a monomer component, and lactic acid and other monomer components (for example, a mixture thereof). , Other hydroxycarboxylic acids, lactones, dicarboxylic acids, diols, etc.) are also included. Other hydroxycarboxylic acids include, for example, glycolic acid, 2-methyllactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxy-3,3-dimethyl. Butyric acid, 2-hydroxycaproic acid and the like can be mentioned. Examples of the lactone include γ-butyrolactone, δ-valerolactone, ε-caprolactone and the like. In addition, examples of the dicarboxylic acid include the dicarboxylic acids exemplified and described as the components constituting the polyester-based resin described above. In addition, examples of the diol include diols exemplified and described as components constituting the polyester resin described above. These other monomeric components may be mixed with lactic acid in a monomeric state and introduced into the polymer as a random copolymer, an oligomer prepolymerized as a polyester, or lactic acid and a block as a prepolymer. It may be guided into the polymer in the form of forming a polymer.

The composition ratio (content ratio of D-form and L-form) of the optical isomers of lactic acid constituting the polylactic acid-based polymer varies depending on the required physical properties and is not particularly limited, but from the viewpoint of controlling the degree of crystallization. , The ratio of D-lactic acid to the total lactic acid component is 1 to 20% by weight (preferably 1 to 15% by weight), or the ratio of L-lactic acid to the total lactic acid component is 1 to 20% by weight (preferably 1 to 1% by weight). 15% by weight) is preferable. Above all, the ratio of D-lactic acid to the total lactic acid component is more preferably 1 to 20% by weight.

The ratio of lactic acid to all the monomers constituting the polylactic acid-based polymer is not particularly limited, but is preferably 50 mol% or more, more preferably 65 mol% or more, and further preferably 80 mol% or more. The upper limit of the above ratio is not particularly limited, but may be 100 mol%. Only one type of the polylactic acid-based polymer may be used, or two or more types may be used. For example, two or more kinds of polylactic acid-based polymers having different ratios of L-lactic acid and D-lactic acid can be used in combination.

The polylactic acid-based polymer can be produced, for example, by polymerizing lactic acid produced from starch obtained from corn, potatoes, or the like as a raw material. The polymerization method is not particularly limited, and known or commonly used methods such as a compression polymerization method and a ring-opening polymerization method can be adopted. For example, in the reduced polymerization method, lactic acid or a polylactic acid-based polymer having an arbitrary composition can be obtained by directly dehydrating and condensing lactic acid and other monomer components. Further, in the ring-opening polymerization method, a polylactic acid-based polymer having an arbitrary composition can be obtained by polymerizing lactide, which is a cyclic dimer of lactic acid, in the presence of an appropriate catalyst.

The weight average molecular weight (Mw) of the polylactic acid-based polymer is not particularly limited, but is usually about 5,000 to 100,000, preferably about 10,000 to 50,000 from the viewpoint of mechanical properties and melt viscosity. .. If the weight average molecular weight is too small, the mechanical properties and heat resistance may be inferior. If the weight average molecular weight is too large, the molding processability may decrease.

The content of the polyester resin in the surface layer is 50% by weight or more, preferably 55% by weight or more, more preferably 60% by weight or more, still more preferably, based on the total weight (100% by weight) of the surface layer. Is 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more. The upper limit of the content is not particularly limited, but may be 100% by weight, less than 100%, 99% by weight or less, and 98% by weight or less. When the content is 50% by weight or more, the heat shrinkage can be increased. It also has excellent transparency. The content of the polyester resin is the total content of all the polyester resins contained in the surface layer.

The surface layer is not particularly limited, but may contain a resin other than the polyester resin. Examples of resins other than the polyester-based resin include thermoplastic resins such as polystyrene-based resins, polyolefin-based resins, vinyl chloride-based resins, polycarbonate-based resins, polyamide-based resins, and thermoplastic elastomers. As the resin other than the polyester resin, only one kind may be used, or two or more kinds may be used. When the surface layer contains a resin other than the polyester resin, the content of the resin is 50% by weight or less (for example, more than 0% by weight) with respect to the total weight (100% by weight) of the surface layer. 50% by weight or less), preferably 30% by weight or less, and more preferably 10% by weight or less. The surface layer may contain a resin other than the polyester resin, but it is most preferable not to contain the resin.

The surface layer is a lubricant, a filler, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, an antifogging agent, a flame retardant, a coloring agent, and a pinning agent (alkali) within a range that does not impair the effects of the present invention. It may contain additives such as earth metal), softeners and compatibilizers. Further, the surface layer may contain a recovery raw material obtained by repelleting a film piece at the time of film production. In the present specification, the recovered raw material consists of non-product parts such as before and after commercialization and film edges, residual parts when a product film is collected from an intermediate product, film scraps such as non-standard products, and polymer scraps. It is a recycled raw material. However, the recovered raw material is preferably one produced from the production of the shrink film of the present invention (so-called self-recovered product).

<Base layer>
The base layer portion is sandwiched between two surface layers in the shrink film. The base layer portion is a layer having a polystyrene resin content of 50% by weight or more, a polyester resin content of more than 30% by weight and 92% by weight or less, and a styrene elastomer content as a layer in the base layer portion. Has at least a layer having a content of 3 to 30% by weight and a polystyrene-based resin other than the styrene-based elastomer in an amount of 5% by weight or more and less than 67% by weight. In the present specification, the layer in which the polystyrene-based resin content is 50% by weight or more is the "A layer", the polyester-based resin content is more than 30% by weight and 92% by weight or less, and the styrene-based elastomer. A layer having a content of 3 to 30% by weight and a polystyrene resin content other than the styrene-based elastomer of 5% by weight or more and less than 67% by weight may be referred to as "B layer".

The base layer portion is composed of 3 to 65 layers. The base layer portion may be formed of only the A layer and the B layer, or may include layers other than the A layer and the B layer as long as the effects of the present invention are not impaired.

The layer A and the layer B may overlap each other. For example, a polyester resin is contained in an amount of more than 30% by weight and 92% by weight or less, a styrene elastomer is contained in an amount of 3 to 30% by weight, and a polystyrene resin other than the styrene elastomer is contained in an amount of 5% by weight or more and less than 67% by weight. Moreover, the layer in which the total content of the polystyrene-based resin is 50% by weight or more is both the A layer and the B layer. However, in the shrink film of the present invention, the A layer and the B layer are layers having different compositions.

(Layer A)
The A layer contains a polystyrene resin as an essential component. As the polystyrene-based resin, only one kind may be used, or two or more kinds may be used. Further, the layer A is not particularly limited, but may contain a resin other than the polystyrene-based resin.

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

The styrene-based monomer is not particularly limited, but for example, styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, p-isobutylstyrene, pt-butylstyrene, and the like. Examples thereof include chloromethylstyrene. Of these, styrene is preferable from the viewpoint of availability, material price, and the like. As the styrene-based monomer, only one kind may be used, or two or more kinds may be used.

The polystyrene-based resin is not particularly limited, but for example, a homopolymer of a styrene-based monomer such as general-purpose polystyrene (GPPS) which is a homopolymer of styrene; only two or more kinds of styrene-based monomers are used alone. Copolymers composed as metric components; Styrene-diene copolymers; Styrene-polymerizable unsaturated carboxylic acid ester-based copolymers and the like; Polystyrene and synthetic rubber (for example, polybutadiene, polyisoprene and the like) ), Impact-resistant polystyrene (HIPS) such as polystyrene obtained by graft-polymerizing styrene on synthetic rubber; a polymer containing a styrene-based monomer (for example, a styrene-based monomer and a (meth) acrylic acid ester-based simple substance. Styrene in which a rubber-like elastic body is dispersed in a continuous phase of (copolymer with a metric) and the copolymer is graft-polymerized on the rubber-like elastic body (graft-type impact-resistant polystyrene called "graft HIPS"). ; Styrene-based elastomer and the like can be mentioned. As the polystyrene-based resin, a styrene-diene-based copolymer is particularly preferable. As the polystyrene-based resin, only one kind may be used, or two or more kinds may be used.

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

The diene is not particularly limited, but conjugated diene is preferable, and for example, 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, 1, Examples thereof include 3-pentadiene, 1,3-hexadiene and chloroprene. Of these, 1,3-butadiene is particularly preferable from the viewpoint of stretch characteristics, heat shrinkage, and interlayer strength. That is, as the styrene-diene copolymer, a styrene-butadiene copolymer is preferable. As the diene, only one kind may be used, or two or more kinds may be used.

The monomer component constituting the styrene-diene copolymer may further contain a monomer component other than the styrene-based monomer and the diene. Examples of the monomer component other than the styrene-based monomer and the diene include a vinyl-based monomer, a polymerizable unsaturated carboxylic acid ester, and a polymerizable unsaturated carboxylic acid anhydride.

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 them, block copolymers are preferable, and examples thereof include styrene block (S) -diene block (D) type, SD type, DSD type, SDSD type and the like. ..

Examples of the block copolymer of the styrene-diene-based copolymer (styrene-diene block copolymer) include a styrene-butadiene block copolymer (SBC) such as a styrene-butadiene-styrene block copolymer (SBS). ), Styrene-isoprene block copolymer such as styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-isoprene block copolymer such as styrene-butadiene / isoprene-styrene block copolymer (SBIS), etc. Among them, a styrene-butadiene block copolymer is preferable. As these block copolymers, only one kind may be used, or two or more kinds may be used.

The styrene-butadiene block copolymer may be a copolymer having a styrene block in which only a styrene-based monomer is polymerized and a butadiene block in which only butadiene is polymerized, and is not particularly limited. For example, styrene-butadiene block copolymer. A styrene-butadiene block copolymer having styrene blocks at both ends, such as a butadiene-styrene block copolymer (SBS) and a styrene-butadiene-styrene-butadiene-styrene block copolymer (SBSBS); a styrene-butadiene copolymer (SB), styrene-butadiene block copolymer having a styrene block such as styrene-butadiene-styrene-butadiene copolymer (SBSB) and a butadiene block at the ends; butadiene-styrene-butadiene copolymer (BSB), butadiene Examples thereof include a styrene-butadiene block copolymer having a butadiene block such as −styrene-butadiene-styrene-butadiene copolymer (BSBSB) at both ends. Among them, a styrene-butadiene block copolymer having a styrene block at both ends is preferable, and SBS is more preferable. As these styrene-butadiene block copolymers, only one kind may be used, or two or more kinds may be used.

The styrene-diene block copolymer can be produced by a known or conventional method for producing a block copolymer. As a method for producing the styrene-diene block copolymer, for example, living polymerization (living radical polymerization, living anionic polymerization, living) in which the molecular weight, molecular weight distribution, terminal structure and the like of the styrene-diene block copolymer can be easily controlled. Cationic polymerization, etc.). The living polymerization can be carried out by a known or conventional method.

The styrene-diene copolymer is not particularly limited, but from the viewpoint of shrinkage characteristics, the content of the structural unit derived from the styrene monomer is the total weight (100% by weight) of the styrene-diene copolymer. ), More preferably more than 50% by weight and 90% by weight or less, still more preferably 60 to 85% by weight, and particularly preferably 65 to 80% by weight. When the content is 50% by weight or more, the shrink film is appropriately hardened, the rigidity of the shrink label is appropriately increased, and the shrinkage characteristics when the shrink label is attached are improved, which is preferable. When the content is 95% by weight or less, appropriate shrinkage stress and shrinkage characteristics can be obtained, which is preferable.

The styrene-diene-based copolymer is not particularly limited, but the content of the constituent unit derived from diene is 5 to 50% by weight with respect to the total weight (100% by weight) of the styrene-diene-based copolymer. Is preferable, more preferably 10% by weight or more and less than 50% by weight, still more preferably 15 to 40% by weight, and particularly preferably 20 to 35% by weight. When the content is 50% by weight or less, the shrink film is appropriately hardened, the rigidity of the shrink label is appropriately increased, and the shrinkage characteristics when the shrink label is attached are improved, which is preferable. When the content is 5% by weight or more, appropriate shrinkage stress and shrinkage characteristics can be obtained, which is preferable.

The styrene-diene copolymer is preferably a plastomer (that is, a styrene-diene copolymer plastomer) rather than an elastomer having properties as an elastomer.

When the styrene-diene-based copolymer contained in the layer A contains two or more kinds of styrene-diene-based copolymers, the content of the structural unit derived from the styrene-based monomer and the diene are derived. The content of each of the constituent units is the content in all the styrene-diene-based copolymers.

The content of the structural unit derived from the styrene-based monomer and the content of the structural unit derived from the diene are the compositions of the styrene-diene-based copolymer (each contained in each styrene-diene-based copolymer). It can be controlled by the content of the structural unit and the content of each styrene-diene-based copolymer in all the styrene-diene-based copolymers contained in the layer). More specifically, for example, in the above-mentioned styrene-diene-based copolymer, the content of the structural unit derived from the styrene-based monomer is s ₁ (% by weight) and the content of the structural unit derived from the diene is d. _The content of 1 (% by weight) of the styrene-diene-based copolymer (PS1) and the constituent units derived from the styrene-based monomer is s ₂ (% by weight) and the content of the constituent units derived from diene is It is a resin mixture composed only of a styrene-diene copolymer (PS2) which 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. _When the content of 1 (% by weight) and PS2 is W ₂ (% by weight), the content of the structural unit derived from the styrene-based polymer and the content of the structural unit derived from the diene in the resin mixture are contained. The amount can generally be controlled as follows. In addition, the content of the structural unit derived from the styrene-based monomer of the styrene-diene-based copolymer elastomer or the styrene-diene-based copolymer which may be contained in the B layer described later and the configuration derived from the diene. The same applies to the content of the unit.
Content of constituent units derived from styrene-based monomer (% by weight) = (s ₁ x W ₁ + s ₂ x W ₂ ) / 100
Content of constituent units derived from diene (% by weight) = (d ₁ x W ₁ + d ₂ x W ₂ ) / 100

The analysis and measurement of the above-mentioned structural unit (the structural unit derived from the styrene-based monomer and the structural unit derived from the diene) and the content of the above-mentioned structural unit are not particularly limited, but for example, nuclear magnetic resonance (NMR) and gas chromatograph. This can be done by a tograph mass spectrometer (GCMS) or the like. It should be noted that the analysis / measurement of the constituent unit or the content of the constituent unit in the other resin layer (B layer or the like) or the resin can be performed in the same manner.

The polystyrene-based resin is not particularly limited, but may be hydrogenated. That is, the polystyrene-based resin may be a hydrogenated polystyrene-based resin (hydrogenated polystyrene-based resin). The hydrogenated polystyrene-based resin is not particularly limited, but is styrene-ethylene-butylene-styrene block copolymer (SEBS), which is a resin obtained by adding hydrogen to SBS, or styrene-, which is a resin obtained by adding hydrogen to SIS. Hydrogenated styrene-diene-based copolymers such as ethylene-propylene-styrene block copolymer (SEPS) are preferred. The hydrogenated polystyrene-based resin such as SEBS and SEPS may be hydrogenated to all diene or partially hydrogenated. As the hydrogenated polystyrene-based resin, only one kind may be used, or two or more kinds may be used.

Further, the polystyrene-based resin is not particularly limited, but a polar group may be introduced. That is, the polystyrene-based resin may be a polystyrene-based resin (modified polystyrene-based resin) into which a polar group has been introduced. The modified polystyrene-based resin includes a hydrogenated polystyrene-based resin into which a polar group has been introduced.

The modified polystyrene-based resin is a polystyrene-based resin having a polystyrene-based resin as a main chain skeleton and having a polar group introduced therein. The polar group is not particularly limited, but for example, an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, a carboxylated compound group, a carboxylic acid amide group, a carboxylic acid base, a sulfonic acid group, and a sulfonic acid ester group. , Sulfonate group, sulfonic acid amide group, sulfonic acid base, isocyanate group, epoxy group, amino group, imide group, oxazoline group, hydroxyl group and the like. Of 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 the polar group, only one kind may be used, or two or more kinds may be used. The modified polystyrene-based resin has a polar group that has a high affinity with the polyester-based resin or is reactive, and is compatible with the polystyrene-based resin, so that the layer containing the polyester-based resin as a main component (for example, , Surface layer, etc.) and layers containing polystyrene resin as the main component (for example, other A layers, etc.) tend to have high adhesiveness at room temperature.

The modified polystyrene-based resin is not particularly limited, but a modified SEBS and a modified SEPS are preferable. That is, the modified polystyrene-based 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. As the modified polystyrene-based resin, only one kind may be used, or two or more kinds may be used.

The polystyrene-based resin is not particularly limited, but may be a soft polystyrene-based resin. The soft polystyrene-based resin is not particularly limited as long as it can be used as a polystyrene-based resin that improves the adhesiveness between the layers in the shrink film of the present invention due to its softness. The soft polystyrene-based resin is not particularly limited, and examples thereof include a styrene-based elastomer, a styrene-diene-based copolymer, HIPS (high-impact polystyrene) having a large amount of rubber component, and a graft HIPS having a large amount of rubber component. Of these, styrene-based elastomers and styrene-diene-based copolymers are preferable. As the soft polystyrene resin, only one kind may be used, or two or more kinds may be used. Examples of the styrene-based elastomer include those exemplified and described as the styrene-based elastomer contained in the B layer described later. The HIPS having a large amount of the rubber component means a HIPS in which the content of the rubber component exceeds 30% by weight with respect to the total weight (100% by weight) of the HIPS. Further, the graft HIPS having a large amount of the rubber component means a 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-based resin includes a hydrogenated soft polystyrene-based resin (hydrogenated soft polystyrene-based resin). The hydrogenated soft polystyrene-based resin is not particularly limited, but a hydrogenated styrene-based elastomer and a hydrogenated styrene-diene-based copolymer (particularly, a styrene-diene-based copolymer having a large amount of hydrogenated diene component) are used. preferable.

As the polystyrene-based resin, a styrene-diene copolymer (particularly, a styrene-diene copolymer plastomer) is preferable, and styrene-butadiene is more preferable, from the viewpoints of shrinkage characteristics, stretching characteristics, and interlayer strength. Polymers (particularly styrene-butadiene copolymer plastomers), more preferably styrene-butadiene block copolymers (particularly styrene-butadiene block copolymer plastomers), particularly preferably styrene-butadiene having styrene blocks at both ends. A block copolymer (particularly, a styrene-butadiene block copolymer plastomer having a styrene block at both ends), most preferably SBS.

Commercially available products may be used as the polystyrene resin, for example, "Clearlen 530L" and "Clearlen 730L" manufactured by Denki Kagaku Kogyo Co., Ltd., "Toughpren 126S" and "Asaprene T411" manufactured by Asahi Kasei Corporation, and Clayton Polymer. "Clayton D1102A", "Clayton D1116A" manufactured by Japan Co., Ltd., "Styrolux S", "Styrolux T" manufactured by Stylolution Co., Ltd., "Asaflex 840", "Asaflex 860" manufactured by Asahi Kasei Chemicals Co., Ltd. SBS), PS Japan Co., Ltd. "679", "HF77", "SGP10", DIC Corporation "Dickstyrene XC-515", "Dickstyrene XC-535" (above, GPPS), PS Japan Co., Ltd. "475D", "H0103", "HT478", DIC Corporation "Dick Polystyrene GH-8300-5" (HIPS), Asahi Kasei Chemicals Co., Ltd. "Tough Tech H Series", Shell Japan Co., Ltd. "Clayton G Series" (above, SEBS), JSR Co., Ltd. "Dynaron" (hydrophobicized polystyrene-butadiene random copolymer), Kuraray Co., Ltd. "Septon" (SEPS), Asahi Kasei Chemicals "Tough Tech M Series" manufactured by Tough Tech Co., Ltd., "Epofriend" manufactured by DIC CORPORATION, "Polar Group Modified Dynalon" manufactured by JSR Co., Ltd., "Rezeda" manufactured by Asahi Kasei Corporation (above, modified polystyrene resin), Examples include "Tough Tech P Series" (hydrated styrene-based elastomer) manufactured by Asahi Kasei Chemicals Co., Ltd.

The content of the structural unit derived from the styrene-based monomer in all the polystyrene-based resins contained in the layer A is not particularly limited, but is based on the total weight (100% by weight) of the polystyrene-based resin in the layer A. It is preferably 50 to 95% by weight, more preferably 60 to 90% by weight, still more preferably 65 to 85% by weight, and particularly preferably 70 to 80% by weight. When the content is 50% by weight or more, the shrink film tends to be appropriately hardened, the rigidity of the shrink label of the present invention is appropriately increased, and the shrinkage characteristics when the shrink label is attached tend to be good. When the content is 95% by weight or less (particularly, 85% by weight or less), it tends to be possible to obtain appropriate shrinkage stress and shrinkage characteristics.

The content of the constituent unit derived from diene in all the polystyrene-based resins contained in the layer A is not particularly limited, but is 5 to 5 based on the total weight (100% by weight) of the polystyrene-based resin in the layer A. It is preferably 50% by weight, more preferably 10 to 40% by weight, still more preferably 15 to 35% by weight, and particularly preferably 20 to 30% by weight. When the content is 50% by weight or less, the shrink film tends to be appropriately hardened, the rigidity of the shrink label of the present invention is appropriately increased, and the shrinkage characteristics when the shrink label is attached tend to be good. When the content is 5% by weight or more (particularly, 15% by weight or more), it tends to be possible to obtain appropriate shrinkage stress and shrinkage characteristics.

The content of the polystyrene resin in the layer A is 50% by weight or more, preferably 55% by weight or more, more preferably 60% by weight or more, still more preferably, based on the total weight (100% by weight) of the layer A. Is 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more. The upper limit of the content may be 100% by weight. When the content is 50% by weight or more, the shrink film is appropriately hardened, the rigidity of the shrink label of the present invention is appropriately increased, and the shrinkage characteristics when the shrink label is attached are improved. When two or more kinds of polystyrene resins are contained in the A layer, the above-mentioned "content of polystyrene resins in the layer A" is the content of all polystyrene resins contained in the layer A. Is the total.

The layer A is not particularly limited, but may contain a resin other than the polystyrene-based resin. Examples of resins other than polystyrene-based resins include polyester-based resins, polyolefin-based resins, vinyl chloride-based resins, polycarbonate-based resins, polyamide-based resins, thermoplastic resins such as thermoplastic elastomers, and the like. When the A layer contains a resin other than the polystyrene resin, the polyester resin is particularly preferable. As the resin other than the polystyrene-based resin, only one kind may be used, or two or more kinds may be used. When the A layer contains a resin other than the polystyrene resin, the content of the resin is 50% by weight or less (for example, more than 0% by weight) with respect to the total weight (100% by weight) of the A layer. 50% by weight or less), preferably 5 to 45% by weight, more preferably 15 to 40% by weight. The layer A may contain a resin other than the polystyrene-based resin, but it is most preferable not to contain the resin.

The A layer is a lubricant, a filler, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, an antifogging agent, a flame retardant, a coloring agent, and a pinning agent (alkali) within a range that does not impair the effects of the present invention. It may contain additives such as earth metal), softeners, and compatibilizers. Only one kind of these components may be used, or two or more kinds may be used. Further, the layer A may contain a recovery raw material obtained by repelleting a film piece at the time of film production.

(B layer)
The B layer contains a polyester resin, a styrene elastomer, and a polystyrene resin other than the styrene elastomer as essential components. As the polyester resin, the styrene elastomer, and the polystyrene resin other than the polystyrene elastomer, only one kind may be used, or two or more kinds may be used respectively. In the present specification, polystyrene-based resins other than the above-mentioned styrene-based elastomer may be referred to as "other polystyrene-based resins". Further, the B layer is not particularly limited, but may contain a resin other than the polyester-based resin, the styrene-based elastomer, and other polystyrene-based resins.

The styrene-based elastomer is a polymer composed of a styrene-based monomer as an essential monomer component, and has properties as an elastomer. That is, it is a polymer containing at least a structural unit derived from a styrene-based monomer in the molecule (in one molecule) and has properties as an elastomer.

The styrene-based elastomer includes, for example, a copolymer elastomer composed of a styrene-based monomer and one or more monomer components (monomer components other than the styrene-based monomer) as essential monomer components. (Styrene-based copolymer elastomer) and the like.

The styrene-based elastomer is not particularly limited as long as it contains the styrene-based monomer, but the content of the structural unit derived from the styrene-based monomer is based on the total weight (100% by weight) of the styrene-based elastomer. , 0% by weight and 60% by weight or less, more preferably 1 to 50% by weight, still more preferably 5 to 45% by weight, and particularly preferably 10 to 40% by weight.

Examples of the styrene-based monomer in the styrene-based elastomer include the monomer components exemplified and described as the styrene-based monomer in the polystyrene-based resin described above. Examples of the monomer component other than the styrene-based monomer include the monomer components exemplified and described as the monomer component other than the styrene-based monomer in the polystyrene-based resin described above. Among the monomer components other than the styrene-based monomer, diene is preferable. That is, as the styrene-based elastomer, a copolymer elastomer (styrene-diene-based copolymer elastomer) composed of a styrene-based monomer and one or more dienes as essential monomer components is preferable.

The diene used as the monomer component of the styrene-diene-based copolymer elastomer is not particularly limited, but a conjugated diene is preferable, for example, 1,3-butadiene, isoprene (2-methyl-1,3-butadiene). ), 2,3-Dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, chloroprene and the like. Of these, 1,3-butadiene is particularly preferable from the viewpoint of stretch characteristics, heat shrinkage, and interlayer strength. That is, as the styrene-diene copolymer elastomer, a styrene-butadiene copolymer elastomer is preferable. As the diene, only one kind may be used, or two or more kinds may be used.

The styrene-diene-based copolymer elastomer contains 40% by weight or more of a constituent unit derived from diene with respect to the total weight (100% by weight) of the styrene-diene-based copolymer elastomer. The system copolymer elastomer is preferable, more preferably 50% by weight or more, still more preferably 55 to 95% by weight, and particularly preferably 60 to 90% by weight.

The glass transition temperature (Tg) of the styrene-based elastomer is not particularly limited, but is preferably 20 ° C. or lower, more preferably 10 from the viewpoint of adhesiveness between the surface layer and the A layer and adhesiveness between the B layers. ° C or lower, more preferably 0 ° C or lower.

The styrene-based elastomer may be a hydrogenated styrene-based elastomer. The styrene-based elastomer includes an elastomer obtained by hydrogenating the styrene-diene-based copolymer elastomer (hydrogenated styrene-diene-based copolymer elastomer (particularly, a styrene-diene-based copolymer having a large amount of hydrogenated diene component). Combined polymer)) is preferred. Examples of the hydrogenated styrene-diene-based copolymer elastomer include styrene-ethylene / butylene-styrene block copolymer elastomer and styrene-ethylene / propylene-styrene block copolymer elastomer. The hydrogenated styrene-diene-based copolymer elastomer may be hydrogenated to all diene or partially hydrogenated. The content of the structural unit derived from diene such as ethylene, butylene, and propylene in the hydrogenated styrene-diene copolymer elastomer and the structural unit derived from non-hydrogenated diene. The preferable range of the total of the above is the same as the preferable range of the content of the constituent unit derived from diene in the above-mentioned styrene-diene-based copolymer elastomer.

Among the styrene-based elastomers, styrene-diene-based copolymer elastomers and hydrogenated styrene-diene-based copolymer elastomers are preferable, and from the viewpoint of superior transparency of the shrink film, styrene-diene-based copolymer elastomers ( That is, a styrene-diene-based copolymer elastomer without hydrogenation) is particularly preferable.

The content of the styrene-based elastomer in the B layer is 3 to 30% by weight, preferably 4 to 25% by weight, and more preferably 5 to 22% by weight, based on the total weight (100% by weight) of the B layer. , More preferably 6 to 20% by weight. When the content is within the above range, the adhesiveness between the surface layer and the A layer is improved, and delamination between the surface layer and the base layer portion is less likely to occur. When two or more kinds of styrene-based elastomers are contained in the B layer, the above-mentioned "content of the styrene-based elastomer in the B layer" is the content of all the styrene-based elastomers contained in the B layer. Is the total.

The polyester-based resin (polyester-based resin contained in the B layer) is not particularly limited, and examples thereof include polyester-based resins exemplified and described as the polyester-based resin contained in the surface layer. The polyester-based resin may be the same polyester-based resin as the polyester-based resin contained in the surface layer, or may be a different polyester-based resin, but the same polyester-based resin is preferable. Therefore, the preferred embodiment of the polyester resin contained in the B layer is the same as the preferred embodiment of the polyester resin contained in the surface layer described above.

The content of the polyester resin in the B layer is more than 30% by weight and 92% by weight or less with respect to the total weight (100% by weight) of the B layer. The lower limit of the content is not particularly limited, but is preferably 40% by weight or more, more preferably 50% by weight or more, and further preferably more than 50% by weight. The upper limit of the content is not particularly limited, but is preferably 80% by weight or less, and more preferably 70% by weight or less. When the content exceeds 30% by weight, the adhesiveness with the surface layer is further improved, and delamination is less likely to occur. In addition, the shrinkage characteristics are further improved.

The other polystyrene-based resin is not particularly limited, and examples thereof include polystyrene-based resins other than the styrene-based elastomer among the polystyrene-based resins exemplified and described as the polystyrene-based resin contained in the layer A described above. The other polystyrene-based resin may be the same polystyrene-based resin as the polystyrene-based resin contained in the layer A, or may be a different polystyrene-based resin, but may be the same polystyrene-based resin. preferable. Therefore, the preferred embodiment of the other polystyrene-based resin contained in the B layer is the same as the preferred embodiment of the polystyrene-based resin contained in the A layer described above.

The content of the other polystyrene-based resin in the B layer is 5% by weight or more and less than 67% by weight with respect to the total weight (100% by weight) of the B layer. The lower limit of the content is not particularly limited, but is preferably 10% by weight or more, and more preferably 15% by weight or more. The upper limit of the content is not particularly limited, but is preferably 65% by weight or less, more preferably 55% by weight or less, still more preferably 45% by weight or less, and particularly preferably less than 40% by weight. When the content is 5% by weight or more, the adhesiveness with the A layer is further improved, and delamination is less likely to occur. In addition, the shrink label of the present invention has a better shrinkage finish.

The content of the polystyrene-based resin in the B layer (that is, the total content of the styrene-based elastomer and other polystyrene-based resins) is not particularly limited, but is 10 with respect to the total weight (100% by weight) of the B layer. It is preferably% by weight or more, more preferably 20% by weight or more, still more preferably 30% by weight or more. The upper limit of the content is not particularly limited, but is preferably 70% by weight or less, more preferably 60% by weight or less, still more preferably 50% by weight or less, and particularly preferably less than 50% by weight. When the content is 10% by weight or more, the adhesiveness with the A layer is further improved, and delamination is less likely to occur. In addition, the shrink label of the present invention has a better shrinkage finish.

The B layer is not particularly limited, but may contain a polyester resin, a styrene elastomer, and a resin other than the polystyrene resin (other resin). Examples of the other resins include polyolefin resins, vinyl chloride resins, polycarbonate resins, polyamide resins, thermoplastic resins such as thermoplastic elastomers other than styrene elastomers, and the like. As the above other resins, only one kind may be used, or two or more kinds may be used. When the B layer contains other resin, the content of the resin is less than 62% by weight (for example, more than 0% by weight and 62% by weight) with respect to the total weight (100% by weight) of the B layer. Less than), preferably 10% by weight or less, more preferably 5% by weight or less. However, it is particularly preferable that the above other resins are not substantially contained in the B layer.

The B layer is a lubricant, a filler, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, an antifogging agent, a flame retardant, a coloring agent, and a pinning agent (alkali) within a range that does not impair the effects of the present invention. It may contain additives such as earth metal), softeners, and compatibilizers. Only one kind of these components may be used, or two or more kinds may be used. Further, the B layer may contain a recovery raw material obtained by repelleting a film piece at the time of film production.

(Layer structure of base layer, physical properties, etc.)
The base layer portion is composed of two outermost layers, which are layers in the base layer portion and are located on both end faces in the thickness direction, and a single or a plurality of intermediate layers sandwiched between the outermost layers and located inside in the thickness direction. NS. That is, the base layer portion has a structure of [outermost layer / intermediate layer / outermost layer] or [outermost layer / intermediate layer / ... / intermediate layer / outermost layer]. When there are a plurality of A layers in the base layer portion, all or some of the plurality of A layers in the base layer portion may be the same layer, which is specified in the present invention. The layers may be different from each other within the range of the A layer (layers having different resin compositions and layer thicknesses). 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 the present invention. The layers may be different from each other within the range of the B layer specified in the invention (layers having different resin compositions and layer thicknesses). Further, the A layer and the B layer may be the outermost layer of the base layer portion, the intermediate layer, or both of them, respectively, may be included in the base layer portion. However, at least one of the two outermost layers in the base layer portion is the B layer, and at least one outermost layer, the B layer, is directly laminated on the surface layer provided with the printing layer. It is preferable that both outermost layers are the B layer. Further, when the printing layers are provided on both sides of the shrink film of the present invention, at least one of the outermost layers of the two outermost layers of the base layer portion may be the B layer, but both are the B layers. Is preferable. When both outermost layers are the B layer, delamination between the surface layer and the base layer portion is less likely to occur.

In the base layer portion, the raw material compositions are different between the layers in the adjacent base layer portion. This is because if the raw material compositions of the layers in the adjacent base layer portion are the same, the interface between the adjacent layers in the base layer portion cannot be seen, and the layers are overlapped to form one layer.

The base layer portion is not particularly limited, but may have a layer other than the A layer and the B layer (sometimes referred to as “E layer”) as a layer in the base layer portion. When there are a plurality of E layers in the base layer portion, all or some of the plurality of E layers may be the same layer or different layers (resin compositions constituting the layers). And layers with different layer thicknesses). Further, the E layer may be the outermost layer of the base layer portion or the intermediate layer.

The E layer is not particularly limited as long as it is a layer that can be laminated with at least one of the surface layer, the A layer, and the B layer. Examples of the E layer include layers for imparting various functions to the shrink film and shrink label of the present invention. The E layer is, for example, a polyester resin, a polyolefin resin, a polystyrene resin, a vinyl chloride resin, a vinylidene chloride resin, an ethylene-vinyl alcohol copolymer resin, a polyamide resin, or an ethylene-vinyl acetate copolymer resin. , Ethylene- (meth) acrylic acid ester copolymer resin, urethane resin, resin layer containing thermoplastic resin such as thermoplastic elastomer, resin layer containing as main component, and the like. The layer E does not include a layer corresponding to the A layer and a layer corresponding to the B layer.

The E layer may be a layer (adhesive resin layer) containing an adhesive resin having good adhesiveness to the surface layer, the A layer, and the B layer. Examples of the adhesive resin include ethylene-carboxylic acid ester copolymer resins such as ethylene-vinyl acetate copolymer resins and ethylene- (meth) acrylic acid ester copolymer resins and their anhydrides; thermoplastic elastomers; urethane. Examples include based resins.

The number of layers (number of layers) contained in the base layer portion is 3 to 65 layers, preferably 5 to 65 layers, more preferably 5 to 33 layers, and further preferably 7 to 17 layers. When the number of layers is three or more, the thickness of each layer is reduced in order to maintain the thickness of the shrink film, and delamination tends to occur more easily in the shrink label provided with the printing layer. However, the shrink of the present invention tends to occur. Labels are less likely to be delaminated. In addition, the multi-layered structure improves the rigidity of the shrink film and makes it stiffer, and also reduces the layer thickness of each layer constituting the base layer portion and makes it difficult for light to scatter, so that the haze of the shrink film is lowered and the base layer is formed. It is superior in transparency as compared with a shrink film of the same thickness in which the portion is a single layer. When the number of layers is 65 or less, the thickness of the A layer and the B layer (thickness per layer) does not become too thin when the thickness (total thickness) of the shrink film is within a range suitable for the shrink label. , The effect of using the A layer and the B layer can be easily obtained.

The base layer portion includes one or more layers A as a layer in the base layer portion. The number of layers of the A layer in the base layer portion is not particularly limited, but is preferably 10 to 90% of the number of layers in the base layer portion, more preferably 30 to 70%, still more preferably. Is the number of layers which is 40 to 60%. When the A layer is also the B layer, the number of layers of the A layer in the base layer portion is not limited to the above range.

The base layer portion includes one or more layers B as a layer in the base layer portion. The number of layers of the B layer in the base layer portion is not particularly limited, but is preferably 10 to 90% of the number of layers in the base layer portion, more preferably 30 to 70%, still more preferably. Is the number of layers which is 40 to 60%. When the B layer is also the A layer, the number of layers of the B layer in the base layer portion is not limited to the above range.

The total number of layers A and B is not particularly limited, but is preferably 50% or more, more preferably 60% or more, still more preferably 60% or more, based on the number of layers in the base layer portion. It is 70% or more, more preferably 80% or more, and particularly preferably 90% or more. The upper limit of the total number of layers of the A layer and the B layer may be 100%, and in this case, the base layer portion is formed only from the A layer and the B layer.

In the base layer portion, the B layer is not particularly limited, but it is preferable that the layer adjacent to the surface layer is the A layer, and it is more preferable that all the layers adjacent to the surface layer are the A layer. In particular, in the base layer portion, the A layer and the B layer are not particularly limited, but are preferably laminated alternately, and more preferably directly laminated alternately without interposing another layer. That is, it is most preferable that the base layer portion alternately contains A layer and B layer as layers.

When the base layer portion is composed of three layers, the laminated structure of the base layer portion is (B layer / A layer / B layer), (B1 layer / A layer / B2 layer) (B layer / A1 layer / A2 layer). ), (B1 layer / B2 layer / A layer), (B layer / A layer / E layer), (B layer / E layer / A layer) and the like. Of these, (B layer / A layer / B layer) is particularly preferable. The A1 layer and the A2 layer are A layers having different raw material compositions from each other. Further, the B1 layer and the B2 layer are B layers having different raw material compositions from each other.

When the base layer portion is formed of only the A layer and the B layer, the laminated structure of the base layer portion is, among other things, a laminated structure in which the "A layer / B layer" is repeated as a repeating unit without interposing other layers. It is preferable that Such a laminated structure includes, for example, (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), (B layer / A layer / B layer / ... / A layer / B layer) and the like.

Although not particularly limited, when the base layer portion includes a plurality of A layers and a plurality of B layers, it is preferable that all the A layers are formed from the same raw material, and all the B layers are formed from the same raw material. Is preferable. That is, it is preferable that the A layers and the B layers are each formed from the same raw material. In particular, it is preferable that all layers A have the same composition, and it is preferable that all layers B have the same composition.

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

The shrink film of the present invention preferably has at least a layer structure having a surface layer, a single or a plurality of B layers, and an A layer in this order. The shrink film of the present invention may have only one layer structure or two layers. The shrink film of the present invention preferably has the above layer structure on the side where the print layer is provided.

In the layer structure having the surface layer, a single or a plurality of B layers, and the A layer in this order, when the B layer is a single layer, the layer structure is the same as the layer structure of [Surface layer / B layer / A layer]. Become. Further, when the B layer is a plurality of layers in the above layer structure, the plurality of B layers are B layers having different raw material compositions. For example, when the B layer in the layer structure is composed of two B layers (B1 layer and B2 layer), the layer structure is a layer structure of [surface layer / B1 layer / B2 layer / A layer].

The content of the polyester resin in the shrink film of the present invention is not particularly limited, but is preferably 40% by weight or more, more preferably 45% by weight or more, and further preferably 45% by weight or more, based on the total weight (100% by weight) of the shrink film. It is preferably 50% by weight or more, and particularly preferably more than 50% by weight. When the content is 40% by weight or more, the heat shrinkage is further improved. The upper limit of the content is not particularly limited, but is preferably 80% by weight or less, more preferably 75% by weight or less, and further preferably 70% by weight or less.

The content of the polystyrene resin (including the styrene elastomer) in the shrink film of the present invention is not particularly limited, but is preferably 20% by weight or more, more preferably 20% by weight or more, based on the total weight (100% by weight) of the shrink film. Is 25% by weight or more, more preferably 30% by weight or more. When the content is 20% by weight or more, the shrinkage finish of the shrink label of the present invention is more excellent. The upper limit of the content is not particularly limited, but is preferably 60% by weight or less, more preferably 55% by weight or less, still more preferably 50% by weight or less, and particularly preferably less than 50% by weight.

The thickness (total thickness) of the shrink film of the present invention is not particularly limited, but is preferably 10 to 100 μm, more preferably 15 to 50 μm, and even more preferably 20 to 45 μm. When the thickness is 10 μm or more, the rigidity becomes high.

The thickness of the surface layer (thickness of one layer) is not particularly limited, but is preferably 1 to 15 μm, more preferably 2 to 10 μm, still more preferably 2.5 to 8 μm, and particularly preferably 5 to 8 μm. When the thickness is 1 μm or more, the heat shrinkage of the shrink film is improved. Further, the solvent resistance is improved, the delamination of the surface layer and the base layer portion tends to be less likely to occur, whitening due to the printing ink when the printing layer is provided is less likely to occur, and the transparency tends to be more excellent. In addition, the rigidity is improved. The thickness of each surface layer on both sides of the base layer portion in the shrink film of the present invention may be the same or different from each other.

The thickness of the surface layer on which the print layer is provided is not particularly limited, but is preferably 5 to 15 μm. When the thickness of the surface layer is 5 μm or more, delamination between the surface layer and the base layer portion is less likely to occur. When the print layers are provided on both sides of the shrink film of the present invention, the thickness of at least one surface layer may be within the above range, or the thickness of both surface layers may be within the above range. good. stomach.

The thickness of the base layer portion is not particularly limited, but is preferably 5 μm or more, more preferably 8 to 90 μm, still more preferably 10 to 45 μm, and particularly preferably 11 to 40 μm. When the thickness is 5 μm or more, the rigidity is improved.

The thickness (thickness of one layer) of the layers (A layer, B layer, E layer, etc.) in the base layer portion is not particularly limited, but is preferably 0.1 μm or more, more preferably 0.2 μm or more, and further preferably 0. It is 3 μm or more. The upper limit of the thickness is not particularly limited, but is preferably 15 μm, more preferably 10 μm, and even more preferably 8 μm. When the thickness is 0.1 μm or more, the rigidity is improved. When the thickness is 15 μm or less, the thickness of each layer tends to be thin, and the transparency of the shrink film tends to be further improved. The thickness of the layers in the base layer portion may be the same in all or part of them, or may be different from each other. For example, the outermost layer of the base layer portion may be thinner than the intermediate layer of the base layer portion. The thickness of the B layer in contact with the surface layer provided with the printing layer is preferably 0.5 μm or more, more preferably 0.7 μm or more, and further preferably 0.9 μm or more.

The ratio of the total thickness of the surface layer, the A layer, and the B layer to the thickness (total thickness) of the shrink film is not particularly limited, but is preferably 50% or more, more preferably 70% or more, still more preferably 80% or more. , Especially preferably 90% or more. The upper limit of the above ratio may be 100%.

The ratio of the thickness of the surface layer (total thickness of all surface layers) to the thickness of the base layer portion [(thickness of surface layer) :( thickness of base layer portion)] in the shrink film of the present invention is not particularly limited. 2: 1 to 1:10 is preferable, and 1: 1 to 1: 4 is more preferable. When the base layer portion is thicker than the above ratio of 2: 1, delamination between the surface layer and the base layer portion is less likely to occur. On the other hand, when the surface layer is thicker than the above ratio of 1:10, the rigidity and abrasion resistance of the label are improved.

The T-type peel strength (based on JIS K 6854-3) between the B layer, which is the outermost layer of the base layer, and the surface layer is not particularly limited, but is preferably 0.8 N or more, more preferably 0.9 N or more. , More preferably 1N or more. The upper limit of the T-type peel strength is not particularly limited, but is preferably 10 N or less, and more preferably 8 N or less. When the T-type peel strength is 0.8 N or more, delamination between the surface layer and the base layer portion can be further suppressed. The T-type peel strength between the surface layer on which the printing layer is provided and the B layer is preferably in the above range. Further, the T-type peel strength is that of the shrink film of the present invention in a state where the printing layer is not provided.

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 in a direction different from one direction) from the viewpoint of exhibiting heat shrinkage. Is preferable. Further, it is preferable that all the film layers (surface layer, A layer, B layer, etc.) are oriented in at least one direction. As the shrink film, a film oriented in one direction (uniaxially oriented film) or a film oriented in one direction and in a direction orthogonal to one direction (biaxially oriented film) is often used, and among them, a uniaxially oriented film is used. Films (including films stretched primarily in one direction and slightly stretched in a direction orthogonal to that one direction, substantially unidirectionally stretched) are commonly used.

The film oriented in at least one direction can be obtained by stretching the 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 the unstretched film in one direction, and when it is a biaxially oriented film, the unstretched film is stretched in one direction and the one. It is obtained by stretching in a direction orthogonal to the direction. The shrink label using the shrink film of the present invention can mainly heat shrink in the orientation direction of the shrink film of the present invention.

The heat shrinkage rate (sometimes referred to as "heat shrinkage rate (100 ° C., 10 seconds)" of the shrink film (when not shrunk) of the present invention at 100 ° C. for 10 seconds (warm water treatment) in the main shrinkage direction is Although not particularly limited, it is preferably 40% or more, more preferably 45% or more, still more preferably 50% or more, still more preferably 60% or more, and particularly preferably 65% or more. The upper limit of the heat shrinkage rate (100 ° C., 10 seconds) is not particularly limited, but is preferably 90% and may be 85%. The "main shrinkage direction" is the direction in which the heat shrinkage rate is the largest, and is generally the direction in which the film is mainly stretched. For example, a film stretched substantially in one direction in the width direction. In some cases, it is in the width direction.

The heat shrinkage rate (100 ° C., 10 seconds) of the shrink film (before shrink processing) of the present invention in the direction orthogonal to the main shrinkage direction is not particularly limited, but is preferably −5 to 25%, more preferably. It is -3 to 20%.

The haze value [JIS K 7136 compliant, unit:%] of the shrink film (when not shrunk) of the present invention is not particularly limited, but is preferably 5% or less, more preferably 4.5% or less, still more preferably. Is less than 4%. When the haze value is 5% or less, the transparency of the shrink label is excellent and preferable.

The haze value [JIS K 7136 compliant, unit:%] of the shrink film of the present invention after heat shrinking by 60% in the main shrinkage direction is not particularly limited, but is preferably 5% or less, more preferably 4 It is 5.5% or less, more preferably 4% or less. When the haze value is 5% or less, the film after shrinkage is excellent in transparency and decorativeness even in a highly shrinkable portion.

(Print layer)
The printing layer is provided on the surface layer of the shrink film of the present invention, which is directly laminated with the B layer as the outermost layer of the base layer portion. When both outermost layers of the base layer portion are the B layer, the print layer may be provided on one surface of the shrink film of the present invention or may be provided on both surfaces.

The printing layer is not particularly limited, and examples thereof include known and commonly used printing layers used in shrink labels. Examples of the printing layer include a solvent-drying type printing layer formed by a solvent-drying type printing ink, an active energy ray-curable printing layer formed by an active energy ray-curable printing ink, and the like. The printing layer includes, for example, a design printing layer (color printing layer, etc.) such as a drawing or design of a product name, an illustration, handling precautions, a back printing layer formed of a single color such as white, a film, or the like. Examples thereof include a protective printing layer provided to protect the printing layer, a primer printing layer provided to enhance the adhesion between the film and the printing layer, and the like. The printing layer is not particularly limited, but may be provided only on one side of the shrink film of the present invention, or may be provided on both sides of the shrink film of the present invention. Further, the print layer may be provided on the entire surface (the surface on the side where the print layer is provided) of the shrink film of the present invention, or may be provided on a part of the surface. Further, the printing layer is not particularly limited, but may be a single layer or a plurality of layers. Further, the printing layer can be provided by a well-known or conventional printing method. Above all, the printing layer is preferably provided by a gravure printing method or a flexographic printing method.

The printing layer is not particularly limited, but preferably contains a binder resin as an essential component. Further, if necessary, it may contain coloring pigments such as blue, red, yellow, black and white, and additives such as lubricants, dispersants and defoamers. As the binder resin and the like, only one kind may be used, or two or more kinds may be used.

The binder resin is not particularly limited, and for example, a resin used as a binder resin in known or conventional printing layers and printing inks 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. Of these, acrylic resins and urethane resins are preferable. The coloring pigment is not particularly limited, and for example, a coloring pigment used in a known or conventional printing layer or printing ink can be used. As the coloring pigment, for example, a white pigment such as titanium oxide (titanium dioxide), an indigo pigment such as copper phthalocyanine blue, carbon black, aluminum flakes, mica, and other coloring pigments can be selected and used according to the application. .. In addition, as the coloring pigment, extender pigments such as alumina, calcium carbonate, barium sulfate, silica, and acrylic beads can also be used for the purpose of adjusting gloss and the like.

When a printing layer containing titanium oxide (particularly a printing layer containing a large amount of titanium oxide) is provided as the printing layer, the back surface is difficult to see through and is preferable as a label. It tends to be easily peeled off (printing delamination). However, the shrink label of the present invention can suppress this print delamination. As the printing layer having high hiding power (prevention of show-through), a layer having a titanium oxide content of 30 to 85% by weight, more preferably 40 to 40% by weight, based on the total weight (100% by weight) of the printing layer. It is 84% by weight, more preferably 50 to 83% by weight. As the binder resin contained in the printing layer containing titanium oxide, an acrylic resin and a urethane resin are preferable, and an acrylic resin is particularly preferable.

The solvent-drying type printing layer is formed by applying, for example, a printing ink produced by mixing the binder resin, the solvent, and if necessary, the coloring pigment and other additives, using a printing machine. , It is provided by volatilizing the solvent. On the other hand, the active energy ray-curable printing layer was produced by, for example, mixing the monomer components constituting the binder resin,, if necessary, the coloring pigment, the solvent, and other additives. The printing ink is applied using a printing machine, dried if necessary, and the above-mentioned monomer components are polymerized and cured by irradiation with active energy rays (for example, ultraviolet rays).

The thickness of the print layer is not particularly limited, but is preferably 0.1 to 10 μm, more preferably 0.3 to 5 μm, for example. In particular, the thickness of the print layer having high hiding power is preferably 0.5 μm or more, more preferably 1.0 μm or more.

Therefore, it is preferable that the printing layer includes a layer having a titanium oxide content of 30 to 85% by weight and a thickness of 0.5 μm or more. In particular, it is particularly preferable that the printing layer is a layer containing an acrylic resin and titanium oxide, having a titanium oxide content of 30 to 85% by weight, and having a thickness of 0.5 μm or more. Delamination of the shrink film is more likely to occur when such a print layer is provided, but the shrink label of the present invention is less likely to cause delamination even when such a print layer is provided.

[Shrink label]
The shrink label of the present invention is a shrink label having at least the shrink film and the printing layer of the present invention. The shrink label of the present invention may have a layer other than the shrink film and the printing layer of the present invention.

The layers other than the shrink film and the printing layer of the present invention included in the shrink label of the present invention are not particularly limited, but are other film layers such as non-woven fabrics and foam sheets, and adhesive layers (pressure sensitive adhesive layer, heat sensitive). (Sexual adhesive layer, etc.), protective layer, anchor coat layer, primer coat layer, coating layer, antistatic layer, aluminum vapor deposition layer and the like.

The thickness (total thickness) of the shrink label of the present invention is not particularly limited, but is preferably 10 to 110 μm, more preferably 15 to 90 μm, and even more preferably 20 to 80 μm.

In the shrink label of the present invention, the T-type peel strength (based on JIS K 6854-3) of the surface layer provided with the printing layer and the B layer (B layer adjacent to the surface layer) is not particularly limited, but is 0. It is preferably .5N or more, more preferably 0.6N or more. The upper limit of the T-type peel strength is not particularly limited, but is preferably 10 N or less, and more preferably 8 N or less. When the T-type peel strength is 0.6 N or more, delamination between the surface layer and the base layer portion can be further suppressed. When the shrink label of the present invention has a structure in which a surface layer provided with a printing layer and a B layer are directly laminated on both sides, the T-type peel strength of only one side may be within the above range. , The T-type peel strength on both sides may be within the above range.

The shrink label of the present invention may be a front print shrink label, a back print shrink label, or a double-sided print shrink label. Above all, it is particularly useful to use it as a back print shrink label. In the present specification, the front print label is a label that shows printing without passing through a shrink film, and means a label having a design printing layer in front of the shrink film when the label is viewed. The back-printed label is a label that shows printing through a shrink film, and refers to a label that has a design printing layer on the back side of the shrink film when the label is viewed. The double-sided printing label means a label having a design printing layer on both sides of the shrink film.

1 and 2 are schematic views (partial cross-sectional views) showing a preferred example of the shrink label of the present invention, respectively. The shrink label 3 of the present invention described in FIG. 1 includes a shrink film 1 of the present invention and a print 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 both side surfaces of the base layer portion 12. The base layer portion 12 has three layers, the outermost layer thereof (the layer in contact with the surface layer 11) is the B layer 12a, and the B layer 12a and the A layer 12b are alternately laminated to form a total of three layers. ing. The surface layer 11 provided with the print layer 2 and the B layer 12a, which is the outermost layer of the base layer portion 12, are directly laminated without interposing other layers. Therefore, the shrink label 3 of the present invention has a laminated structure in which the surface layer 11 and the B layer 12a, which is the outermost layer of the base layer portion, are directly laminated. Further, the A layer 12b is interposed between the B layers 12a.

The shrink label 3 of the present invention described in FIG. 2 includes a 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 has a surface layer 11 and a base layer portion 12, and the base layer portion 12 has nine layers, the outermost layer thereof (the layer in contact with the surface layer 11) is the B layer 12a, and the B layer is formed. 12a and A layer 12b are alternately formed by laminating a total of 9 layers. Also in FIG. 2, the surface layer 11 and the base layer portion 12 are directly laminated without interposing another layer, and the surface layer 11 and the B layer 12a which is the outermost layer of the base layer portion 12 interposes the other layer. It is directly laminated without. Therefore, the shrink label 3 of the present invention has a laminated structure in which the surface layer 11 provided with the printing layer 2 and the B layer 12a, which is the outermost layer of the base layer portion, are directly laminated. Further, the A layer 12b is interposed between all the B layers 12a.

The shrink label of the present invention contains two surface layers containing a polyester resin as a main component and a layer (A layer) containing a polystyrene resin as a main component between the two surface layers, and has three or more layers. It has a base layer portion having a multi-layer structure. As a result, the rigidity can be increased while maintaining the thickness of the shrink film, the heat shrinkage property is excellent, and the shrinkage finish is excellent. Further, since the base layer portion has a multi-layer structure, the thickness of each layer can be reduced, which is excellent in transparency. In the present invention, a layer (B layer) containing a specific amount of a polyester resin, a styrene elastomer, and a polystyrene resin other than the styrene elastomer as the outermost layer of the base layer portion directly laminated with the surface layer provided with the printing layer. ) Is included to improve the interlayer strength between the surface layer and the base layer portion, thereby making it difficult for delamination between the surface layer and the base layer portion to occur. Further, even if the printing layer is a plurality of printing layers or a printing layer formed by a printing ink containing a highly soluble solvent, delamination between the surface layer and the base layer portion is unlikely to occur.

[Method for manufacturing shrink label of the present invention]
The shrink label of the present invention can be obtained by a production method including at least a step of producing the shrink film of the present invention (film production step) and a printing layer forming step. In addition, other steps (steps other than the above-mentioned film manufacturing step) such as a step of forming a layer other than the shrink film of the present invention may be included.

(Film production process)
The shrink film of the present invention can be produced by a conventional method such as melt film formation. Of these, the melt film forming method (particularly, the T-die method) is preferable. Further, as the laminating method, a conventional method, for example, a coextrusion method (feed block method, multi-manifold method, etc.), a dry laminating method, or the like can be used. Among them, the coextrusion method is preferable, and the feed block method is preferable. When the base layer portion has four or more layers, the base layer portion is further multi-layered by using a layer multiplier, particularly by using a feed block and a layer multiplier in combination. Is preferable. The layer multiplier is a device for multi-layering a film layer. The method of multi-layering 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 above "layer multiplier" may be simply referred to as "multiplier". The multiplier can be obtained from, for example, EDI and Chloren.

A specific example of the coextrusion method (feed block method) will be described below. For example, the raw material for forming the base layer portion and the raw material for forming the surface layer are each put into a plurality of extruders set to predetermined temperatures, and coextruded from a T die, a circular die, or the like. At this time, it is preferable to use a manifold or a feed block to form a predetermined laminated structure. When the base layer portion has four or more layers, it is preferable to use a feed block and a multiplier in combination to form a multi-layered base layer portion to form a predetermined laminated structure. Further, if necessary, the supply amount may be adjusted by using a gear pump. Further, it is preferable to remove the foreign matter by using a filter because the film tear can be reduced. The extrusion temperature varies depending on the type of raw material used and is not particularly limited, but is preferably 150 to 250 ° C. Further, the temperature of the merging portion and the die is preferably 200 to 250 ° C. A laminated unstretched film (sheet) can be obtained by quenching the co-extruded polymer using a cooling drum or the like.

The method for producing the shrink film of the present invention is not particularly limited, but when the base layer portion is formed of the A layer and the B layer, the raw material constituting the A layer (sometimes referred to as “raw material (a)”) and The raw material constituting the B layer (sometimes referred to as "raw material (b)") and the raw material constituting the surface layer (sometimes referred to as "raw material (c)") are melted (or melt-kneaded), respectively. First step; The raw material (a) and the raw material (b) melted (or melt-kneaded) in the first step are laminated, and if necessary, further multilayered to form a laminated body. The second step; and it is preferable that both sides of the laminate formed in the second step include at least a third step of laminating the raw material (c) melted in the first step. Further, other stages (stages other than the first stage, the second stage, and the third stage) may be included. The other stage may be, 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, and the like. It may be provided at the position of.

In the first step, it is preferable to melt (or melt-knead) the raw materials (a), the raw materials (b), and the raw materials (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 put into three extruders set to predetermined temperatures, respectively, to perform melting (or melt kneading). The extrusion temperature is not particularly limited, but is preferably 150 to 250 ° C.

In the second step, the laminated body obtained by laminating the raw material (a) and the raw material (b) melted in the first step and further multi-layering the raw material (a) is not particularly limited, but for example, the melting. The raw material (a) and the raw material (b) can be laminated in sequence or simultaneously laminated (coextruded) using a feed block. In addition, the laminated body may be a laminated body formed by further multi-layering the above-mentioned sequentially laminated or co-extruded laminated body using a multiplier. The lamination is not particularly limited, but it is preferable to use a feed block and a multiplier in combination. As the feed block and the multiplier, only 1 may be used, or 2 or more may be used, respectively. In the above laminated body, the total number of layers formed from the raw material (a) and the total number of layers formed from the raw material (b) is preferably 3 to 65 layers, more preferably 5 to 33 layers, still more preferably. Is 9 to 33 layers. The laminate obtained in the second step forms the base layer portion of the shrink film of the present invention.

In the second step, the raw material (a) and the raw material (b) are laminated, and the laminated body further multi-layered is specifically, for example, the raw material (a) melted in the first step. And the raw material (b) are extruded using a feed block to prepare a laminate having the composition of [raw material (b) / raw material (a) / raw material (b)] (sometimes referred to as “laminate 1”). Then, the laminate 1 is used as one unit and laminated using a multiplier to obtain [raw material (b) / raw material (a) / raw material (b) / raw material (b) / raw material (a) / raw material (b). ) / ... / Raw material (b) / Raw material (a) / Raw material (b)] can be obtained as a laminate (sometimes referred to as "laminate 2").

In addition, in the second step, the raw material (a) and the raw material (b) are laminated, and the laminated body further multi-layered is specifically, for example, the raw material melted in the first step. (A) and the raw material (b) are extruded using a feed block to prepare a laminate having the constitution of [raw material (a) / raw material (b)] (sometimes referred to as “laminate 3”). Next, the laminated body 3 is used as one unit and 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 4”) can be obtained. In addition, the laminated body 4 can be traced from the opposite direction of [raw material (b) / raw material (a) / raw material (b) / raw material (a) / ... / raw material (b) / raw material (a)]. It is also a laminated body having a structure.

When laminating the raw material (c) melted in the first step on both side surfaces of the laminate (for example, laminate 2 or 4) formed in the second step in the third step. It is preferable to use a feed block. The laminated raw material (c) forms a 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 side surfaces of the laminate formed in the second step is obtained.

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

In addition, [raw material (b) / raw material (a) / raw material (b) / raw material (b) / raw material (a) / raw material (b) / ... / raw material (b) / raw material (a) / raw material ( b)] The above-mentioned laminated body 2 has a structure of [B layer / A layer / B layer / B layer / A layer / B layer / ... / B layer / A layer / B layer]. Although it should be the base layer portion, in reality, the interface of the [B layer / B layer] portion formed from the [raw material (b) / raw material (b)] in which the same materials of the laminated body 2 are laminated becomes invisible 1 Since it is one B layer, it is a base layer portion having a structure of [B layer / A layer / B layer / A layer / ... / B layer / A layer / B layer]. When the surface layer and the outermost layer (resin layer) of the base layer portion are layers made of the same resin composition as a raw material, the interface thereof becomes invisible, and the surface layer and the outermost layer of the base layer portion are separated from each other. It becomes one layer (surface layer).

The other steps are not particularly limited, and examples thereof include a stretching step (stretching step), a surface treatment step, and the like. For example, the laminated unstretched film produced in the third step then further has a stretching step.

The stretching step includes biaxial stretching in the longitudinal direction (film production line direction; also referred to as MD direction) and width direction (direction orthogonal to the longitudinal direction; also referred to as TD direction), uniaxial stretching in the longitudinal direction or width direction, and the like. 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 at the same time, or biaxial stretching may be performed sequentially. More specifically, for example, after stretching at a stretching temperature of 65 to 100 ° C. in the longitudinal direction and a stretching ratio of 1.05 to 1.50 times by the roll method, stretching at a stretching temperature of 70 to 100 ° C. in the width direction by the tenter method. Stretch 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 a conventional surface treatment such as a corona discharge treatment, a primer treatment, and a frame treatment on the surface of the shrink film of the present invention.

In the above film manufacturing step, an example in which the base layer portion is formed only from the A layer and the B layer has been described, but even when a layer other than the A layer and the B layer is included, the base layer portion and the laminated unstretched film are formed by the same step. Can be made.

(Print layer forming process)
In the printing layer forming step, the printing layer can be formed by applying a printing ink on at least one surface of the shrink film of the present invention and solidifying it by drying or curing. As a method for applying the printing ink, a known and commonly used method can be used, and among them, gravure printing, flexographic printing, and digital printing are preferable. Further, when the applied printing ink is dried or solidified by heating or the like, a general heating device capable of heating on the printing device can be preferably used. From the viewpoint of safety, a hot air heater or the like can be preferably used. For example, in a design printing layer, the above printing ink is generally applied a plurality of times for each color to form a printing layer which is a plurality of layers.

When the printing ink is a solvent-drying type printing ink, the printing ink is produced by mixing, for example, a binder resin, a solvent, and other additives (coloring pigments, etc.), if necessary. Mixing can be performed by a known and commonly used mixing method, and is not particularly limited, but for example, a mixer such as a paint shaker, a butterfly mixer, a planetary mixer, a pony mixer, a dissolver, a tank mixer, a homomixer, a homodisper, or a roll mill. , Sand mills, ball mills, bead mills, line mills and other mills, kneaders and other mixing devices are used. The mixing time (residence time) at the time of mixing is not particularly limited, but is preferably 10 to 120 minutes. The obtained printing ink may be used after being filtered, if necessary. As each of the above components (binder resin, solvent, and other additives), only one type may be used, or two or more types may be used.

As the solvent, water, an organic solvent, or the like usually used for printing inks used for gravure printing, flexographic printing, and the like can be used. Examples of the organic solvent include esters such as acetates (eg, ethyl acetate, propyl acetate, butyl acetate); alcohols such as methanol, ethanol, isopropyl alcohol, propanol and butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; toluene. Aromatic hydrocarbons such as xylene; aliphatic hydrocarbons such as hexane and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; glycols such as ethylene glycol and propylene glycol; ethylene glycol monopropyl ether and propylene glycol monomethyl ether , Glycol ethers such as propylene glycol monobutyl ether; glycol ether esters such as propylene glycol monomethyl ether acetate and the like. The solvent can be removed by drying after applying the printing ink to the shrink film of the present invention. The solvent also includes the meaning of "dispersion medium".

[Cylindrical shrink label]
The shrink label of the present invention is, for example, a tubular shrink label of a type in which both ends of the label are sealed with a solvent or an adhesive to form a cylinder and attached to a container, or one end of the label is attached to a container and the label is wound around. 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 tubular shape. Among the above, the shrink label of the present invention 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, a tubular shrink label using the shrink label of the present invention may be referred to as a “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. 3 and 4. The tubular shrink label 4 of the present invention shown in FIG. 3 has a tubular shape in which the other end is overlapped with the outside of one end of the shrink label of the present invention formed in a rectangular shape, and the inner surface and one end of the other end are formed. It is a tubular body in which the outer surface of the portion is joined with a solvent or an adhesive to form the seal portion 41. The tubular 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 tubular shrink label of the present invention and is heat-shrinkable in that direction. The tubular shrink label of the present invention is preferably attached so that the circumferential direction is the main contraction direction. Further, even in the case of a winding type shrink label, it is preferable that the label is formed into a cylinder so that the circumferential direction is the main contraction direction (that is, the stretching direction).

FIG. 4 is an enlarged view of a cross section of IV-IV'in FIG. 3, that is, a main part of the tubular shrink label 4 of the present invention near the seal portion. It is joined with an adhesive 53. Specifically, the shrink label of the present invention covers a region excluding a region having a predetermined width from the other end of one surface (the surface on the inner surface side of the tubular shape) of the shrink film 1 of the present invention. 52 is formed, and the back printing layer 51 is formed in substantially the entire area excluding the region of a predetermined width from the other end of one surface of the shrink film 1 of the present invention so as to cover the design printing layer 52. Has been done. Therefore, in the shrink label of the present invention, the back printing layer 51 and the design printing layer 52 are not formed in the region having a predetermined width from the other end, and the shrink film 1 of the present invention is exposed and the film. An exposed surface is formed, and the seal portion 41 uses a solvent or an adhesive 53 to form an exposed film surface formed on the inner surface side of the other end of the shrink label of the present invention and an outer surface (exposed film surface) of one end thereof. It is joined. That is, in the seal portion 41, it is preferable that the shrink films 1 of the present invention are bonded to each other with a solvent or an adhesive 53. Of the above-mentioned both ends, the portions that are not joined may have a print layer because the adhesiveness is not affected even if the back print layer, the design print layer, or the like has a print layer or the like.

In the tubular shrink label 4 of the present invention in FIG. 4, one end extends to a position where the end overlaps with the back printing layer 51 at the other end, and the back printing layer 51 at one end and the other end extends. A region where the two overlap each other is formed via the shrink film 1 of the present invention. Therefore, there is no region where the back print layer 51 does not exist in the thickness direction. The tubular shrink label of the present invention may have a structure that overlaps the back printing layer on the one end end side and the other end side (that is, overlaps in the thickness direction, that is, in the surface spreading direction) as shown in FIG. However, the end of one end and the other end extend to the region where the end of one end overlaps the exposed surface of the film at the other end, and the end of one end does not extend to the position where it overlaps the back printing layer on the other end side. The structure may be such that the back printing layer on the side does not overlap.

The width of the seal portion is not particularly limited, but is preferably 0.2 to 10 mm, more preferably 0.3 to 5 mm, and even more preferably 0.4 to 2 mm.

(Manufacturing method of tubular shrink label)
The method for producing the tubular shrink label of the present invention is not particularly limited, but is as follows, for example. The elongated shrink label of the present invention is slit to a predetermined width to obtain a long label body in which a plurality of the shrink labels of the present invention are connected in the elongated direction (longitudinal direction). The long label body is formed into a tubular shape by overlapping so that the heat-shrinkable direction (that is, the heat-shrinkable direction of the shrink film) is the circumferential direction and the other end is outside the one end. , The overlapped portion is sealed in a strip shape with a predetermined width and both ends are joined to obtain a long tubular label continuum (long tubular shrink label). By cutting this long tubular shrink label in the circumferential direction, one tubular shrink label having a predetermined length in the height direction (the tubular shrink label of the present invention) can be obtained. When providing a perforation for cutting the label, a conventional method (for example, a method of pressing a disc-shaped blade in which a cut portion and a non-cut portion are repeatedly formed around the perforation, a method using a laser, etc.) is used. Can be applied. The process of perforating can be appropriately selected after providing the printing layer, before and after the process of processing into a cylindrical shape, and the like.

[Labeled container]
The shrink label of the present invention is not particularly limited, but is attached to a container and used as a labeled container. The shrink label of the present invention may be used for an adherend other than the container. For example, a shrink label of the present invention (particularly, a tubular shrink label) is arranged around a container so that the shrink label of the present invention has a tubular shape, and is attached to the container by heat shrinking to be labeled. A container (labeled container with the shrink label of the present invention) is obtained. The above containers include, for example, soft drink bottles such as PET bottles, home delivery milk bottles, food containers such as seasonings, alcoholic beverage bottles, pharmaceutical containers, chemical product containers such as detergents and sprays, and toiletries. Includes containers, cup noodle containers, etc. The shape of the container is not particularly limited, and examples thereof include various shapes such as a bottle type such as a cylindrical shape and a square shape, and a cup type. The material of the container is not particularly limited, and examples thereof include plastics such as PET, glass, and metals. The container to which the shrink label of the present invention is attached may be referred to as "the labeled container of the present invention".

The labeled container can be produced, for example, by externally fitting a tubular shrink label into a predetermined container and then heat-shrinking the tubular shrink label by heat treatment to bring it into close contact with the container (shrink processing). Examples of the heat treatment method include a method of passing through a hot air tunnel and 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. It is also possible to use dry steam at 101-140 ° C. The heat treatment is not particularly limited, but is preferably carried out in a temperature range in which the temperature of the shrink film is 85 to 100 ° C. (particularly 90 to 97 ° C.). The shrink label of the present invention can be used for a container that requires a high heat shrinkage rate. The heat treatment time is preferably 4 to 20 seconds from the viewpoint of productivity and economy.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples. In addition, Example 5 is described as a reference example.

In Table 1, the raw materials for the surface layer, the raw materials for the resin layer (A), the raw materials for the resin layer (B), the shrink films and the shrink labels produced in the examples and the comparative examples, which were used in the examples and the comparative examples, are shown. The composition and evaluation results are shown.

Example 1
(material)
As a raw material constituting the surface layer (raw material for the surface layer), 100% by weight of polyester resin B (manufactured by Eastman Chemical Company, trade name "EMBRACE LV", Tg: 69 ° C.) was used.
As a raw material (raw material for the resin layer (A)) constituting the resin layer (A), polystyrene resin A (manufactured by Stylolution Co., Ltd., trade name "Stylolux T", content of a structural unit derived from butadiene: 25 weights %) Was used in an amount of 70% by weight, and polystyrene resin B (manufactured by Stylolution Co., Ltd., trade name “Stylolux S”, content of constituent units derived from butadiene: 12% by weight) was used in an amount of 30% by weight.
As raw materials constituting the resin layer (B) (raw materials for the resin layer (B)), polyester resin B is 54% by weight, polystyrene resin A is 27% by weight, polystyrene resin B is 12% by weight, and styrene elastomer. A (manufactured by Asahi Kasei Co., Ltd., trade name "Toughprene 126S") was used in an amount of 7% by weight.

(Shrink film)
The extruder x heated to 220 ° C. is the raw material for the resin layer (A), the extruder heated to 220 ° C. is the raw material for the resin layer (B), and the extruder z heated to 250 ° C. is the raw material for the surface layer. Was thrown in. Melt extrusion was performed using the above three extruders. A resin layer using a laminating device in which the raw material for the molten resin layer (A) and the raw material for the molten resin layer (B) are combined with a feed block having a merging method of two types and three layers and a multiplier divided into four parts. The raw material for (B) / the raw material for the resin layer (A) / the raw material for the resin layer (B) is divided, merged, and laminated as one repeating unit, and the laminated body (I) (the above two types 3). A laminated body (II) in which four layer structures are laminated (repeated number 4), and the melted raw material for the surface layer is merged and laminated on both side surfaces of the laminated body (I) using a feed block. ). Further, the laminate (II) was extruded from a T-die and then rapidly cooled on a casting drum cooled to 25 ° C. to obtain a laminated unstretched film having surface layers on both sides of the base layer portion. .. The outermost layers on both sides of the base layer portion are resin layers (B).

Next, the laminated unstretched film is tenter-stretched 6 times at 85 ° C. in the width direction to be uniaxially stretched mainly in the width direction, and a long stretched film (shrink film) having heat shrinkage in the direction. I got a body. In Example 1, the resin layer (A) corresponds to the A layer, and the resin layer (B) corresponds to the B layer.

(Cylindrical shrink label)
Binder resin (trade name "Dianar BR-64", acrylic resin, manufactured by Mitsubishi Rayon Co., Ltd.) 10% by weight, pigment (trade name "JR-") with respect to the long body of the shrink film obtained above. 805 ”, titanium oxide, manufactured by Teika Co., Ltd.) 50% by weight, wax 3% by weight, ethyl acetate 19% by weight, and n-propyl acetate 18% by weight. Made by commercial gravure, applied using the trade name "GRAVO PROOF MINI"), dried and solidified, and a white back printing layer (thickness: 3 μm) is formed on the entire surface other than the part that becomes the seal part, and the length of the shrink label. I got a scale. Next, the long body of the shrink label is slit to have a predetermined width, and then one end and the other end are overlapped to form a tubular shape so that the width direction is the circumferential direction, and the one end and the other end are formed into a tubular shape. The shrink film surfaces of the parts were sealed with a solvent to obtain a tubular elongated body with a shrink label. Further, the tubular elongated body (label continuum) of the shrink label was cut into individual label sizes to obtain a tubular shrink label.

Examples 2-5, Comparative Examples 1 and 2
As shown in Table 1, the composition and component ratio of the raw material for the resin layer (A), the raw material for the resin layer (B), and the raw material for the surface layer are changed, and the shrink film and the tubular shrink are obtained in the same manner as in Example 1. Got a label. In Examples 2 to 5, the resin layer (A) corresponds to the A layer, and the resin layer (B) corresponds to the B layer. Further, as the polyester resin A, the trade name "EMBRACE" (manufactured by Eastman Chemical Company, Tg: 71 ° C.) was used.

(evaluation)
The shrink films obtained in Examples and Comparative Examples were evaluated as follows. The evaluation results are shown in Table 1.

(1) Peeling strength (shrink film)
For the shrink films obtained in Examples and Comparative Examples, the T-type peel strength between the surface layer and the resin layer (B), which is the outermost layer of the base layer portion, was measured by the following method.
From the shrink film, a rectangular sample with a width of 15 mm in the longitudinal direction of the shrink film (film formation direction of the shrink film) and a length of 200 mm in the width direction of the shrink film (orthogonal direction with the longitudinal direction) [length 200 mm (shrink) (Width direction of film) x width 15 mm (longitudinal direction of shrink film)] was collected. In the following, the long side direction of the sample refers to the width direction of the shrink film, and the width direction of the sample refers to the longitudinal direction of the shrink film.
A T-type peeling test (according to JIS K 6854-3) was performed under the following conditions with the long side direction of the sample as the measurement direction, and the peeling load between layers was measured.
The average value of the peeling load was defined as the T-type peeling strength (N).
(Measurement condition)
Measuring device: Autograph manufactured by Shimadzu Corporation (AG-IS: load cell type 500N)
Temperature and humidity: Temperature 23 ± 2 ° C, Humidity 50 ± 5% RH
Initial chuck interval: 40 mm
Sample width: 15 mm
Number of tests: 3 times Tensile speed: 200 mm / min Stroke: 150 mm
First half deletion range: 50 mm
Sensitivity: 1

(2) Peeling strength (shrink label)
Similar to the above "(1) Peeling strength (clear)" except that the tubular shrink label obtained in Examples and Comparative Examples was used, the surface layer and the base layer portion on the side where the printing layer was provided were the most. The T-type peel strength between the resin layer (B), which is the outer layer, was measured.

As can be seen from Table 1, the shrink labels (Examples 1 to 5) of the present invention contained a large amount of titanium oxide and had high interlayer strength even when a relatively thick print layer was formed. .. In addition, the shrink labels obtained in Examples 1 to 4 were also excellent in transparency (particularly, transparency after shrinking by 60%). On the other hand, when the resin layer (B) did not contain the styrene-based elastomer (Comparative Example 1) or when the resin layer (B) did not contain the polyester-based resin (Comparative Example 2), the interlayer strength was low.

1 Shrink film of the present invention 11 Surface layer 12 Base layer part 12a B layer 12b A layer 2 Printing layer 3 Shrink label of the present invention 4 Cylindrical shrink label of the present invention 41 Sealing part D Circumferential direction 51 Back surface printing layer 52 Design printing layer 53 Solvent or adhesive

Claims (4)

A shrink label having a shrink film and a printing layer provided on at least one surface of the shrink film.
The shrink film has a base layer portion and surface layers provided on both sides of the base layer portion.
The surface layers provided on both sides are layers having a polyester resin content of 90 % by weight or more.
The base layer portion contains 3 to 65 layers, and as layers in the base layer portion , a layer (A layer) having a polystyrene resin content of 90 % by weight or more and a polyester resin content of 50 to 50 to It has at least a layer (B layer) having 70% by weight, a styrene-based elastomer content of 5 to 22 % by weight, and a polystyrene-based resin content other than the styrene-based elastomer of 15 % by weight or more and less than 40% by weight. , At least one of the outermost layers of the base layer portion is the B layer,
The styrene-based elastomer in the layer B has a content of a structural unit derived from a styrene-based monomer of 10 to 50 % by weight and a content of a structural unit derived from a diene of 50 to 90% by weight. Diene-based copolymer elastomer
The polystyrene resin other than the styrene-based elastomer in the B layer has a content of structural units derived from styrene-based monomers of 65 to 90 % by weight and a content of structural units derived from diene of 10 to 35% by weight. % Is a styrene-diene-based elastomer,
The polystyrene-based resin in the layer A has a content of a structural unit derived from a styrene-based monomer of 65 to 90% by weight and a content of a structural unit derived from a diene of 10 to 35% by weight. It is a diene-based copolymer and
A shrink label having at least a structure in which a surface layer provided with the printing layer and a layer B, which is the outermost layer of the base layer portion, are directly laminated. The shrink label according to claim 1, wherein the polystyrene-based resin content in the B layer is 30 to 50% by weight. The shrink according to claim 1 or 2, wherein the T-type peel strength (according to JIS K 6854-3) between the surface layer provided with the printing layer and the B layer adjacent to the surface layer is 0.5 N or more. label. The shrink label according to any one of claims 1 to 3, wherein the printed layer contains a layer having a titanium oxide content of 30 to 85% by weight and a thickness of 0.5 μm or more.

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