JP2018052560A - Shrink label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shrink label hardly causing delamination while being provided with a printing layer.SOLUTION: The shrink label includes a shrink film 1, a printing layer 2 arranged at least one side of the shrink film, a base layer 12, and surface layers 11 arranged on both sides of the base layer. In the surface layer, content of polyester based resin is 50 wt% or more. The base layer is constituted by 3 to 65 layers. The layers in the base layer at least include (A layers) 12b with content of polystyrene based resin being 50 wt% or more, and (B layers) 12a with content of polystyrene based resin being more than 30 wt% and not more than 92 wt%, content of styrene based elastomer being 3 to 30 wt%, content of polystyrene based resin other than the styrene based elastomer being 5 wt% or more and less than 67 wt%. The layer structure is so configured that at least one of the outermost surfaces of the base layer is B layer, and a surface layer arranged with a printing layer and the B layer being the outermost layer of the base layer are directly laminated.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a shrink label.

  Currently, plastic containers such as PET bottles and metal bottles such as bottle cans are widely used as containers for beverages such as tea and soft drinks. In many cases, plastic labels are attached to these containers for display, decoration, and functionality. As such a plastic label, for example, a shrink label in which a printing layer is provided on a shrink film (heat-shrinkable film) from the merits of decoration, workability (followability to containers), a wide display area, and the like. Widely used.

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

JP 2009-178887 A

  In recent years, shrink labels are required to be thin from the viewpoint of cost reduction and resource saving. However, a shrink film having a structure in which different materials as described in Patent Document 1 are laminated may have a reduced interlayer strength and a tendency to cause delamination as the thickness is reduced. In addition, even when the delamination does not occur as a shrink film, when a printing layer is provided on the shrink film, the solvent contained in the printing ink forming the printing layer is eroded between layers of different materials laminated. However, delamination sometimes occurred. For example, when a printing ink containing a low-volatile solvent or a printing ink containing a large amount of an ester solvent is used as the printing ink, or when a plurality of printing layers are formed thickly by overcoating, etc. When a printing layer containing a large amount of pigment such as titanium oxide was formed, delamination was likely to occur.

  Accordingly, an object of the present invention is to provide a shrink label that is difficult to cause delamination while being provided with a printing layer.

  That is, the present invention is a shrink label having a shrink film and a printed layer provided on at least one surface of the shrink film, wherein the shrink film is provided on both the base layer portion and the base layer portion. The surface layer provided on both sides is a layer having a polyester resin content of 50% by weight or more, and the base layer portion includes 3 to 65 layers, and the base layer As a layer in the part, a layer (A layer) having a polystyrene-based resin content of 50% by weight or more, a polyester-based resin content exceeding 30% by weight and 92% by weight or less, and a styrene-based elastomer content 3 to 30% by weight, and a layer (B layer) in which the content of polystyrene resin other than the styrene elastomer is 5% by weight or more and less than 67% by weight, There is provided a shrink label characterized in that at least one of the layers is a B layer, and 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 is provided. .

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

  The base layer portion preferably includes 5 to 65 layers.

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

  The printed layer preferably includes 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-described configuration, delamination hardly occurs while the printing layer is provided.

It is the schematic (partial sectional drawing) which shows an example of the shrink label of this invention. It is the schematic (partial sectional drawing) which shows another example of the shrink label of this invention. It is the schematic which shows an example of the cylindrical shrink label which is one Embodiment of the shrink label of this invention. FIG. 4 is a schematic diagram showing an example of a cylindrical shrink label that is an embodiment of the shrink label of the present invention (enlarged view of essential parts in the section IV-IV ′ in FIG. 3).

  The shrink label of this invention has a shrink film and the printing layer provided in the at least one surface of this shrink film. In the present specification, the shrink film (that is, the shrink film included in the shrink label of the present invention) may be referred to as “the shrink film of the present invention”. The shrink label of this invention may contain layers other than the shrink film of this invention, and the said printing layer within the range which does not impair the effect of this invention.

[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 sides of the base layer portion. Specifically, the shrink film of the present invention has a layer structure of [surface layer / base layer portion / surface layer], and preferably the base layer portion and the surface layer are directly laminated. However, the surface layer on which at least one of the print layers is provided and the base layer are directly laminated. The surface layer 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 this invention may contain layers other than the said base layer part and the said surface layer within the range which does not impair the objective of this invention. The layer other than the base layer and the surface layer is 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 treatment such as corona discharge treatment, primer treatment, and frame treatment.

<Surface layer>
The surface layer in the shrink film of the present invention (that is, the surface layer provided on each side of the base layer portion) is a layer having a polyester resin content of 50% by weight or more. By having the said surface layer, the shrink film of this invention can improve rigidity and can strengthen a waist. In addition, the heat shrinkage rate is improved. Moreover, it is excellent in transparency and solvent resistance.

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

  Examples of the polyester-based resin include 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 polymer, polyester elastomer and the like. Examples of 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′-stilbene dicarboxylic acid, trans-4,4′-stilbene dicarboxylic 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 Indene-4,5-dicarboxylic acid, 1,2-diphenoxyethane-4,4′-dicarboxylic acid, diphenyl ether Aromatic dicarboxylic acids such as dicarboxylic acid, 2,5-anthracene dicarboxylic acid, 2,5-pyridinedicarboxylic acid, and substituted products thereof; oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberin Acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonadecanedioic acid, icosanedioic acid, docosanedioic acid, 1, Aliphatic dicarboxylic acids such as 12-dodecanedioic acid and substituted products thereof; 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid 1,4-decahydronaphthalenedicarboxylic acid, 1,5-decahydronaphth Dicarboxylic acid, 2,6-decahydronaphthalene dicarboxylic acid, and alicyclic dicarboxylic acids such as substituted versions thereof and the like. The said dicarboxylic acid may use only 1 type and may use 2 or more types.

  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, , 3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol and other alicyclic diols; 2,2-bis (4-β-hydroxy And ethylene oxide adducts of bisphenol compounds such as ethoxyphenyl) propane and bis (4-β-hydroxyethoxyphenyl) sulfone, and aromatic diols such as xylylene glycol. The said diol may use only 1 type and may use 2 or more types.

  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. A structural unit derived from a monohydric alcohol such as polyalkylene glycol monomethyl ether; a polyhydric alcohol such as glycerin, pentaerythritol, or trimethylolpropane;

  Among these, from the viewpoints of shrinkage characteristics, rigidity, mechanical strength, etc., the polyester resin is preferably an aromatic polyester resin. The aromatic polyester-based resin means that 50 mol% or more (preferably 70 mol% or more) of the total dicarboxylic acid component is 50 mol% or more (preferably 70 mol% or more of the total diol component). Is a polyester resin whose aromatic diol is 70 mol% or more. Furthermore, the aromatic polyester-type resin which is a polymer by the condensation reaction of the dicarboxylic acid containing aromatic dicarboxylic acid and the diol containing aliphatic diol, or a mixture thereof is preferable.

  From the viewpoint of making the delamination between the surface layer and the base layer portion more difficult by making the polyester-based resin amorphous, the above-mentioned aromatic polyester-based resin, from the viewpoint of stretching characteristics, shrinkage characteristics, and rigidity, A modified aromatic polyester-based resin containing a modifying component (copolymerization component) is preferable instead of being composed of a single repeating unit. As the modified aromatic polyester resin, for example, 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 resin containing a modified component in addition to the main component. Resins are preferred. In other words, the aromatic polyester-based resin is preferably a modified aromatic polyester-based resin including a structural unit derived from at least two kinds of dicarboxylic acids and / or a structural unit derived from at least two kinds of diols.

  Among the above modified aromatic polyester resins, among the above, in polyethylene terephthalate (PET) using terephthalic acid as the dicarboxylic acid component and ethylene glycol (EG) as the diol component, a part of the dicarboxylic acid component and / or 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, and isophthalic acid. Of these, isophthalic acid is preferable. Examples of the diol component used as the modifying component include 2,2-dialkyl-1,3-propanediol such as 1,4-cyclohexanedimethanol (CHDM) and neopentyl glycol (NPG), and diethylene glycol. Among these, CHDM and 2,2-dialkyl-1,3-propanediol (particularly NPG) are preferable. The alkyl group in the 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 or different. It may be an alkyl group.

  The aromatic polyester-based resin is not particularly limited. Specifically, from the viewpoint of heat shrinkability (shrinkage characteristics), PET using terephthalic acid as the dicarboxylic acid component and EG as the diol component; dicarboxylic acid In some cases, terephthalic acid is used as a component, ethylene glycol is a main component (for example, most diol component) as a diol component, and a modified aromatic polyester resin using CHDM as a copolymerization component (“CHDM copolymerized PET”). ); A modified aromatic polyester resin ("2,2") using terephthalic acid as the dicarboxylic acid component, ethylene glycol as the diol component, and 2,2-dialkyl-1,3-propanediol as the copolymer component -"Dialkyl-1,3-propanediol copolymerized PET" Is preferred). Among the 2,2-dialkyl-1,3-propanediol copolymerized PET, in particular, modified fragrance using terephthalic acid as a dicarboxylic acid component, ethylene glycol as a main component as a diol component, and NPG as a copolymerization component. A group polyester resin (sometimes referred to as “NPG copolymerized PET”) is preferred. The aromatic polyester 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 preferred is CHDM copolymerized PET. Note that copolymer components other than CHDM and 2,2-dialkyl-1,3-propanediol are used for the CHDM copolymerized PET and 2,2-dialkyl-1,3-propanediol copolymerized PET, respectively. For example, isophthalic acid or diethylene glycol may be further copolymerized.

  In the modified aromatic polyester resin, the copolymerization ratio of the copolymer component (modified component) [ratio of the copolymerized dicarboxylic acid component to the total dicarboxylic acid component (ratio), or the ratio of the copolymerized 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. Above (for example, 15 to 40 mol%). Among them, for example, in the case of CHDM copolymerized PET, the proportion of CHDM is preferably 10 mol% or more (EG is 90 mol% or less), more preferably 12 mol% or more (EG is 88 mol% or less) in all diol components. ), 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). . Further, the upper limit of the ratio of CHDM is preferably 40 mol% or less (EG is 60 mol% or more), more preferably 35 mol% or less (EG is 65 mol% or more), further preferably 30 mol in all 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 (the ratio of NPG in the case of NPG copolymerized PET) is In the diol component, 10 mol% or more (EG is 90 mol% or less) is preferable, and more preferably 15 mol% or more (EG is 85 mol% or less). Moreover, the upper limit of the ratio of NPG is preferably 40 mol% or less (EG is 60 mol% or more), more preferably 30 mol% or less (EG is 70 mol% or more) in all diol components. Further, a part of the EG component (preferably 1 to 30 mol%, more preferably 1 to 10 mol% in all diol components) may be replaced with diethylene glycol.

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

  The degree of crystallinity of the polyester resin measured by a 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, the polyester-based resin is most preferably one having almost no melting point (melting peak) when measured by the DSC method (that is, a crystallinity of 0%). The crystallinity can be calculated from a value of heat of crystal fusion obtained by DSC measurement, with a sample having a clear crystallinity measured by the X-ray method or the like as a standard. The heat of crystal melting is, for example, using a DSC (Differential Scanning Calorimetry) device manufactured by Seiko Instruments Inc. and performing a nitrogen seal at a sample amount of 10 mg and a heating rate of 10 ° C./min. It can be determined from the area of the melting peak when the temperature is raised to room temperature and then raised again. The crystallinity is preferably measured from a single resin, but when measured in a mixed state, the melting peak of the target aromatic polyester resin is subtracted from the melting peak of the resin to be mixed. You can ask for.

  The weight average molecular weight (Mw) of the polyester-based resin is preferably 15,000 to 100,000, more preferably 15,000 to 90,000, and still more preferably 30,000 to 10,000, from the viewpoint of melting behavior and shrinkage behavior. 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 addition, in this specification, although a weight average molecular weight (Mw) is not specifically limited, For example, it can measure by 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 viewpoints of stretching characteristics and shrinkage characteristics. The Tg can be controlled by the type of dicarboxylic acid or diol 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, for example, JIS K7121. The DSC measurement is not particularly limited. For example, the DSC measurement can be performed using a differential scanning calorimeter “DSC6200” manufactured by Seiko Instruments Inc. under a temperature rising rate of 10 ° C./min.

  Commercially available products may be used as the polyester resin. For example, “EMBRACE 21214”, “EMBRACE LV” (CHDM copolymerized PET) manufactured by Eastman Chemical (Eastman Chemical), Bell Polyester Products, Inc. "Velpet MGG200" (2,2-dialkyl-1,3-propanediol copolymerized PET) manufactured by Bellpolyester Products, "Velpet E02" (NPG copolymerized PET) manufactured by Bell Polyester Products, "Sky Green" manufactured by SK Chemical Co., Ltd. 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, And copolymers with other hydroxycarboxylic acids, lactones, dicarboxylic acids, diols, etc.). 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 Examples include butyric acid and 2-hydroxycaproic acid. Examples of the lactone include γ-butyrolactone, δ-valerolactone, and ε-caprolactone. Moreover, as dicarboxylic acid, the dicarboxylic acid etc. which were illustrated and demonstrated as a component which comprises the above-mentioned polyester-type resin are mentioned. Examples of the diol include diols exemplified and described as components constituting the above-described polyester resin. These other monomer components may be mixed with lactic acid in a monomer state and may be introduced into the polymer as a random copolymer, or oligomers polymerized in advance as polyester, or lactic acid and block copolymer as a prepolymer. It may be introduced into the polymer in the form of a polymer.

  The composition ratio of optical isomers of lactic acid constituting the polylactic acid-based polymer (content ratio of D-form and L-form) varies depending on the required physical properties and is not particularly limited, but from the viewpoint of crystallinity control 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 15% by weight). Especially, the case where the ratio of D-lactic acid with respect to all the lactic acid components is 1 to 20 weight% is more preferable.

  The proportion of lactic acid in all the monomers constituting the polylactic acid 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. Although the upper limit of the said ratio is not specifically limited, 100 mol% may be sufficient. The said polylactic acid-type polymer may use only 1 type, and may use 2 or more types. For example, two or more polylactic acid 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 using starch obtained from corn, moss or the like as a raw material. The polymerization method is not particularly limited, and a known or conventional method such as a condensation polymerization method or a ring-opening polymerization method can be employed. For example, in the polycondensation method, lactic acid or a polylactic acid polymer having an arbitrary composition can be obtained by directly dehydrating condensation of lactic acid and other monomer components. In the ring-opening polymerization method, lactide, which is a cyclic dimer of lactic acid, is polymerized in the presence of an appropriate catalyst to obtain a polylactic acid polymer having an arbitrary composition.

  The weight average molecular weight (Mw) of the polylactic acid 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, moldability may be reduced.

  The content of the polyester-based resin in the surface layer is 50% by weight or more, preferably 55% by weight or more, more preferably 60% by weight or more, and 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 or less than 100%, or 99% by weight or less and 98% by weight or less. When the content is 50% by weight or more, heat shrinkability can be increased. Moreover, it is excellent in transparency. Content of the said polyester-type resin is the sum total of content of all the polyester-type resins contained in a surface layer.

  The surface layer is not particularly limited, but may contain a resin other than the polyester resin. Examples of the resin 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, more preferably 10% by weight or less. The surface layer may contain a resin other than the polyester-based resin, but most preferably does not contain the resin.

  As long as the surface layer does not impair the effects of the present invention, the lubricant, filler, heat stabilizer, antioxidant, ultraviolet absorber, antistatic agent, antifogging agent, flame retardant, colorant, pinning agent (alkali Earth metals), softeners, compatibilizers and other additives may be included. Moreover, the surface layer may contain the collection | recovery raw material which re-pelletized the film piece at the time of film manufacture. In this specification, the recovered raw material includes non-product parts before and after commercialization, film edges and the like, remaining parts when product films are collected from intermediate products, non-standard product film scraps, and polymer scraps. Recycled raw material. However, the recovered raw material is preferably a product (so-called self-recovered product) produced from the production of the shrink film of the present invention.

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

  The base layer portion is composed of 3 to 65 layers. The said base layer part may be formed only from A layer and B layer, and may contain layers other than A layer and B layer in the range which does not impair the effect of this invention.

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

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

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

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

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

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

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

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

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

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

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

  The styrene-diene block copolymer can be produced by a known or conventional method for producing a block copolymer. Examples of the method for producing the styrene-diene block copolymer include living polymerization (living radical polymerization, living anion polymerization, living), which can easily control the molecular weight, molecular weight distribution, terminal structure and the like of the styrene-diene block copolymer. And cationic polymerization). 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 structural units derived from the styrene monomer is such that the total weight of the styrene-diene copolymer (100% by weight). ) Is preferably 50 to 95% by weight, more preferably more than 50% by weight and 90% by weight or less, further preferably 60 to 85% by weight, particularly preferably 65 to 80% by weight. When the content is 50% by weight or more, the shrink film is suitably hardened, the rigidity of the shrink label is moderately high, and the shrinkage property when the shrink label is attached is good, which is preferable. It is preferable for the content to be 95% by weight or less because appropriate shrinkage stress and shrinkage characteristics can be obtained.

  The styrene-diene copolymer is not particularly limited, but the content of structural units derived from diene is 5 to 50% by weight based on the total weight (100% by weight) of the styrene-diene copolymer. More preferably, it is 10 wt% or more and less than 50 wt%, more preferably 15 to 40 wt%, particularly preferably 20 to 35 wt%. 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 property when the shrink label is attached is favorable, which is preferable. It is preferable for the content to be 5% by weight or more because appropriate shrinkage stress and shrinkage characteristics can be obtained.

  The styrene-diene copolymer is preferably an plastomer (that is, a styrene-diene copolymer plastomer), not an elastomer having properties as an elastomer.

  In addition, when the styrene-diene copolymer contained in the A layer contains two or more styrene-diene copolymers, the content of the structural unit derived from the styrene monomer and the diene The content of the structural unit is the content in all the styrene-diene copolymers.

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

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

  The polystyrene resin is not particularly limited, but may be hydrogenated. That is, the polystyrene resin may be a hydrogenated polystyrene resin (hydrogenated polystyrene resin). The hydrogenated polystyrene resin is not particularly limited, but 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. A hydrogenated styrene-diene copolymer such as ethylene / propylene-styrene block copolymer (SEPS) is preferred. The hydrogenated polystyrene resins such as SEBS and SEPS may be hydrogenated to all dienes or partially hydrogenated. Only one kind of the hydrogenated polystyrene resin may be used, or two or more kinds may be used.

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

  The modified polystyrene resin is a polystyrene resin in which a polar group is introduced using a polystyrene resin as a main chain skeleton. The polar group is not particularly limited, and examples thereof include an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, a carboxylic acid chloride group, a carboxylic acid amide group, a carboxylic acid group, a sulfonic acid group, and a sulfonic acid ester group. Sulfonic acid chloride group, sulfonic acid amide group, sulfonic acid group, isocyanate group, epoxy group, amino group, imide group, oxazoline group, hydroxyl group and the like. Among these, an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, and an epoxy group are preferable, and a maleic anhydride group and an epoxy group are more preferable. The said polar group may use only 1 type, and may use 2 or more types. The modified polystyrene-based resin has a polar group that has a high affinity or can react with the polyester-based resin, and is compatible with the polystyrene-based resin, so that a layer containing the polyester-based resin as a main component (for example, , Surface layer, etc.) and a layer containing polystyrene resin as a main component (for example, other A layer, etc.) tend to have high adhesion at room temperature.

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

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

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

  Among the above polystyrene resins, styrene-diene copolymers (particularly styrene-diene copolymer plastomers) are preferable, and styrene-butadiene copolymers are more preferable from the viewpoints of shrinkage characteristics, stretching characteristics, and interlayer strength. Polymer (especially styrene-butadiene copolymer plastomer), more preferably styrene-butadiene block copolymer (especially styrene-butadiene block copolymer plastomer), particularly preferably styrene-butadiene having styrene blocks at both ends. A block copolymer (in particular, a styrene-butadiene block copolymer plastomer having styrene blocks at both ends), most preferably SBS.

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

  Although the content of the structural unit derived from the styrene monomer in all the polystyrene resins contained in the A layer is not particularly limited, with respect to the total weight (100% by weight) of the polystyrene resin in the A layer The content 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 is appropriately hardened, the rigidity of the shrink label of the present invention is appropriately increased, and the shrinkage property when the shrink label is attached tends to be good. When the content is 95% by weight or less (particularly 85% by weight or less), there is a tendency that moderate shrinkage stress and shrinkage characteristics can be obtained.

  Although content of the structural unit derived from the diene in all the polystyrene-type resins contained in A layer is not specifically limited, It is 5 with respect to the total weight (100 weight%) of the polystyrene-type resin in A layer. 50 weight% is preferable, More preferably, it is 10-40 weight%, More preferably, it is 15-35 weight%, Most preferably, it is 20-30 weight%. When the content is 50% by weight or less, the shrink film is appropriately hardened, the rigidity of the shrink label of the present invention is appropriately increased, and the shrinkage property when the shrink label is attached tends to be good. When the content is 5% by weight or more (particularly 15% by weight or more), there is a tendency that appropriate shrinkage stress and shrinkage characteristics can be obtained.

  The content of the polystyrene-based resin in the A layer is 50% by weight or more, preferably 55% by weight or more, more preferably 60% by weight or more, and still more preferably based on the total weight (100% by weight) of the A 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 may be 100% by weight. When the content is 50% by weight or more, the shrink film is moderately hardened, the rigidity of the shrink label of the present invention is moderately 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 “content of polystyrene resin in the A layer” is the content of all polystyrene resins contained in the A layer. Total.

  The A layer is not particularly limited, but may contain a resin other than polystyrene resin. Examples of resins other than polystyrene resins include polyester resins, polyolefin resins, vinyl chloride resins, polycarbonate resins, polyamide resins, and thermoplastic resins such as thermoplastic elastomers. When A layer contains resin other than a polystyrene-type resin, a polyester-type resin is especially 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-based 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 wt% or less), preferably 5 to 45 wt%, more preferably 15 to 40 wt%. In addition, although A layer may contain resin other than the said polystyrene-type resin, it is most preferable not to contain it.

  The layer A is within the range not impairing the effects of the present invention, and includes lubricants, fillers, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, antifogging agents, flame retardants, colorants, pinning agents (alkalis). Earth metals), softeners, compatibilizers and other additives may be included. These components may use only 1 type and may use 2 or more types. Moreover, A layer may contain the collection | recovery raw material which re-pelletized the film piece at the time of film manufacture.

(B layer)
The B layer contains a polyester resin, a styrene elastomer, and a polystyrene resin other than the styrene elastomer as essential components. Each of the polyester resins other than the polyester resin, the styrene elastomer, and the polystyrene elastomer may be used alone or in combination of two or more. In the present specification, polystyrene resins other than the styrene elastomer may be referred to as “other polystyrene resins”. The layer B is not particularly limited, but may contain a resin other than the polyester resin, styrene elastomer, and other polystyrene resins.

  The styrene elastomer is a polymer composed of a styrene 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.

  Examples of the styrenic elastomer include a copolymer elastomer comprising a styrene monomer and one or more monomer components (monomer components other than styrene monomers) as essential monomer components. (Styrene copolymer elastomer) and the like.

  The styrene elastomer is not particularly limited as long as it contains a styrene monomer, but the content of the structural unit derived from the styrene monomer is based on the total weight (100% by weight) of the styrene elastomer. The content is preferably more than 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 monomer in the styrene elastomer include monomer components exemplified and explained as the styrene monomer in the above-mentioned polystyrene resin. Moreover, as monomer components other than the said styrene-type monomer, the monomer component illustrated and demonstrated as a monomer component other than the styrene-type monomer in the above-mentioned polystyrene resin is mentioned, for example. Among them, a diene is preferable as the monomer component other than the styrene monomer. That is, the styrene elastomer is preferably a copolymer elastomer (styrene-diene copolymer elastomer) composed of a styrene monomer and one or more dienes as essential monomer components.

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

  In the styrene-diene copolymer elastomer, the content of constituent units derived from diene is 40% by weight or more based on the total weight (100% by weight) of the styrene-diene copolymer elastomer. A 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 styrenic elastomer is not particularly limited, but is preferably 20 ° C. or less, more preferably 10 from the viewpoints of adhesion between the surface layer and the A layer and adhesion between the B layers. ° C or lower, more preferably 0 ° C or lower.

  The styrene elastomer may be a hydrogenated styrene elastomer. Examples of the styrene elastomer include hydrogenated elastomers of the styrene-diene copolymer elastomers (hydrogenated styrene-diene copolymer elastomers (especially styrene-diene copolymer having a large amount of hydrogenated diene components). Preferred are combined elastomers)). Examples of the hydrogenated styrene-diene copolymer elastomer include a styrene-ethylene / butylene-styrene block copolymer elastomer and a styrene-ethylene / propylene-styrene block copolymer elastomer. The hydrogenated styrene-diene copolymer elastomer may be hydrogenated to all dienes or may be partially hydrogenated. In the hydrogenated styrene-diene copolymer elastomer, the content of structural units derived from hydrogenated structural units derived from dienes such as ethylene, butylene, and propylene and structural units derived from unhydrogenated dienes. The preferable range of the total of is the same as the preferable range of the content of the structural unit derived from diene in the above-mentioned styrene-diene copolymer elastomer.

  Among the styrene elastomers, styrene-diene copolymer elastomers and hydrogenated styrene-diene copolymer elastomers are preferable, and styrene-diene copolymer elastomers (from the viewpoint of excellent transparency of the shrink film) ( That is, a styrene-diene copolymer elastomer that is not hydrogenated is particularly preferred.

  The content of the styrenic elastomer in the B layer is 3 to 30% by weight, preferably 4 to 25% by weight, more preferably 5 to 22% by weight, based on the total weight (100% by weight) of the B layer. More preferably, it is 6 to 20% by weight. When the content is within the above range, the adhesion between the surface layer and the A layer is improved, and delamination between the surface layer and the base layer portion hardly occurs. When two or more types of styrene elastomers are contained in the B layer, the above “content of styrene elastomer in the B layer” is the content of all styrene elastomers contained in the B layer. Total.

  Although it does not specifically limit as said polyester-type resin (The polyester-type resin contained in B layer), For example, the polyester-type resin illustrated and demonstrated as a polyester-type resin contained in the above-mentioned surface layer is mentioned. The polyester resin may be the same polyester resin as the polyester resin contained in the surface layer, or may be a different polyester resin, but is preferably the same polyester resin. Therefore, the preferable aspect of the polyester-type resin contained in B layer is the same as the preferable aspect of the polyester-type resin contained in the above-mentioned surface layer.

  Content of the polyester-type resin in B layer is more than 30 weight% and 92 weight% or less with respect to the total weight (100 weight%) of B layer. Although the minimum of the said content is not specifically limited, 40 weight% or more is preferable, More preferably, it is 50 weight% or more, More preferably, it is more than 50 weight%. Although the upper limit of the said content is not specifically limited, 80 weight% or less is preferable, More preferably, it is 70 weight% or less. When the said content exceeds 30 weight%, adhesiveness with a surface layer will improve more and delamination will not occur more easily. Further, the shrinkage characteristics are further improved.

  Although it does not specifically limit as said other polystyrene-type resin, For example, things other than a styrene-type elastomer are mentioned among the polystyrene-type resin illustrated and demonstrated as a polystyrene-type resin contained in the above-mentioned A layer. The other polystyrene-based resin may be the same polystyrene-based resin as the polystyrene-based resin contained in the A layer or may be a different polystyrene-based resin, but may be the same polystyrene-based resin. preferable. Therefore, the preferable aspect of the other polystyrene-type resin contained in B layer is the same as the preferable aspect of the polystyrene-type resin contained in the above-mentioned A layer.

  The content of other polystyrene-based resins 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. Although the minimum of the said content is not specifically limited, 10 weight% or more is preferable, More preferably, it is 15 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, adhesion with the A layer is further improved, and delamination is less likely to occur. Further, the shrink finish of the shrink label of the present invention is more excellent.

  The content of the polystyrene resin in the B layer (that is, the total content of the styrene elastomer and other polystyrene resins) is not particularly limited, but is 10 with respect to the total weight (100% by weight) of the B layer. % By weight or more is preferable, more preferably 20% by weight or more, and 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, adhesion with the A layer is further improved, and delamination is less likely to occur. Further, the shrink finish of the shrink label of the present invention is more excellent.

  The B layer is not particularly limited, but may contain a resin (other resin) other than a polyester resin, a styrene elastomer, and other polystyrene resins. Examples of the other resins include thermoplastic resins such as polyolefin resins, vinyl chloride resins, polycarbonate resins, polyamide resins, and thermoplastic elastomers other than styrene elastomers. Only one kind of the other resins may be used, or two or more kinds thereof 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 10), preferably 10% by weight or less, more preferably 5% by weight or less. However, it is particularly preferable that the other resins are not substantially contained in the B layer.

  Layer B is within the range not impairing the effects of the present invention, and includes lubricants, fillers, heat stabilizers, antioxidants, UV absorbers, antistatic agents, antifogging agents, flame retardants, colorants, pinning agents (alkali Earth metals), softeners, compatibilizers and other additives may be included. These components may use only 1 type and may use 2 or more types. Moreover, B layer may contain the collection | recovery raw material which re-pelletized the film piece at the time of film manufacture.

(Layer structure and physical properties of the base layer)
The base layer portion is a layer in the base layer portion and is composed of two outermost layers located on both end faces in the thickness direction and one or more intermediate layers located on the inner side in the thickness direction sandwiched between the outermost layers. The That is, the base layer portion has a configuration 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 or defined by 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, Different layers within the range of the B layer specified in the invention (layers having different resin compositions and layer thicknesses) may be used. In addition, the A layer and the B layer may be the outermost layer of the base layer portion, the intermediate layer, or both of them may be included in the base layer portion. However, at least one of the two outermost layers in the base layer portion is a B layer, and the B layer that is at least one outermost layer is directly laminated on the surface layer on which the printing layer is provided. In addition, it is preferable that both outermost layers are B layers. Moreover, when the printing layer is provided in both surfaces of the shrink film of this invention, at least one outermost layer of the two outermost layers of a base layer part should just be a B layer, but both must be a B layer Is preferred. When both outermost layers are B layers, delamination between the surface layer and the base layer portion is less likely to occur.

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

  The 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 composition constituting the layers) Or layers having different layer thicknesses). The E layer may be the outermost layer of the base layer portion or an intermediate layer.

  The E layer is not particularly limited as long as it can be laminated with at least one of the surface layer, the A layer, and the B layer. As said E layer, the layer which provides various functions to the shrink film and shrink label of this invention is mentioned, for example. 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, an ethylene-vinyl acetate copolymer resin. And a resin layer containing a thermoplastic resin such as an ethylene- (meth) acrylate copolymer resin, a urethane resin, and a thermoplastic elastomer, or a resin layer having a main component. The E layer 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 adhesion to the surface layer, the A layer, and the B layer. Examples of the adhesive resin include ethylene-carboxylate copolymer resins such as ethylene-vinyl acetate copolymer resins and ethylene- (meth) acrylate copolymer resins and their anhydrides; thermoplastic elastomers; urethanes Based resins and the like.

  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 still more preferably 7 to 17 layers. When the number of layers is 3 or more, the thickness of each layer is reduced in order to maintain the thickness of the shrink film, and the delamination tends to occur more easily in the shrink label provided with the printed layer. The label is less prone to delamination. In addition, the multi-layer structure improves the rigidity of the shrink film, strengthens it, and reduces the thickness of each layer that makes up the base layer, making it difficult to scatter light, thereby reducing the haze of the shrink film. Compared with a shrink film having the same thickness, the part being a single layer, the transparency is excellent. When the number of layers is 65 or less, when the thickness (total thickness) of the shrink film is within a range suitable for the shrink label, the thickness of the A layer and the B layer (thickness per layer) does not become too thin. The effect of using the A layer and the B layer can be easily obtained.

  The base layer portion includes one or more A layers as layers in the base layer portion. The number of layers of the A layer in the base layer is not particularly limited, but is preferably 10 to 90%, more preferably 30 to 70%, and even more preferably with respect to the number of layers in the base layer. Is the number of layers of 40-60%. In addition, when A layer is also B layer, the number of layers of A layer in a base layer part is not limited to the said range.

  The base layer portion includes one or more B layers as layers in the base layer portion. The number of B layers in the base layer is not particularly limited, but is preferably 10 to 90%, more preferably 30 to 70%, and even more preferably relative to the number of layers in the base layer. Is the number of layers of 40-60%. In addition, when B layer is also A layer, the number of layers of B layer in a base layer part is not limited to the said range.

  The total number of layers of the A layer and the B layer is not particularly limited, but is preferably 50% or more, more preferably 60% or more, and still more preferably with respect to 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%. In this case, the base layer portion is formed only of the A layer and the B layer.

  In the base layer part, the B layer is not particularly limited, but the layer adjacent to the surface layer other than the surface layer is preferably the A layer, and all the layers adjacent to the surface layer other than the surface layer are more preferably the A layer. In particular, in the base layer portion, the A layer and the B layer are not particularly limited, but are preferably alternately stacked, and more preferably directly stacked alternately without any other layer. That is, the base layer portion most preferably includes A layers and B layers alternately as layers.

  When the base layer portion is composed of three layers, the stack 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. Among 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. The B1 layer and the B2 layer are B layers having different raw material compositions.

  In the case where the base layer portion is formed of only the A layer and the B layer, the stack configuration of the base layer portion is, among other things, a stack configuration in which “A layer / B layer” is repeated as a repeating unit without interposing other layers. It is preferable that 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 A layers are formed from the same raw material, and that all the B layers are formed from the same raw material. It is preferable. That is, the A layers and the B layers are preferably formed from the same raw material. Particularly, all the A layers are preferably layers having the same composition, and all the B layers are preferably layers having the same composition.

(Configuration, physical properties, etc. of 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 sides of the base layer part, and is provided on one side and the other side of the base layer part, respectively.

  The shrink film of the present invention preferably has at least a layer structure having a surface layer, one 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. It is preferable that the shrink film of this invention has the said layer structure in the side which provides a printing layer.

  In the layer structure having the surface layer, the single or plural B layers, and the A layer in this order, when the B layer is a single layer, the layer structure is the layer structure of [surface layer / B layer / A layer] Become. In the above layer configuration, when the B layer is a multilayer, the plurality of B layers are B layers having different raw material compositions. For example, when the B layer in the layer configuration is composed of two B layers (B1 layer and B2 layer), the layer configuration is a layer configuration 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, further based on the total weight (100% by weight) of the shrink film. Preferably it is 50% by weight or more, particularly preferably more than 50% by weight. When the content is 40% by weight or more, the heat shrinkability 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 still more 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 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 shrink 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.

  Although the thickness (total thickness) of the shrink film of this invention is not specifically limited, 10-100 micrometers is preferable, More preferably, it is 15-50 micrometers, More preferably, it is 20-45 micrometers. When the thickness is 10 μm or more, the rigidity is increased.

  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 shrinkability of the shrink film is improved. Further, the solvent resistance is improved, the surface layer and the base layer part are less likely to be delaminated, the whitening caused by the printing ink when the printing layer is provided is less likely to occur, and the transparency tends to be more excellent. Further, the rigidity is improved. In addition, the thickness of each surface layer in the both surfaces side of the base layer part in the shrink film of this invention may be the same, and may mutually differ.

  The thickness of the surface layer on which the printing 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. In addition, when the printing layer is provided in both surfaces of the shrink film of this invention, the thickness of at least one surface layer may be in the said range, and the thickness of both surface layers may be in the said range. Good. Yes.

  Although the thickness of a base layer part is not specifically limited, 5 micrometers or more are preferable, More preferably, it is 8-90 micrometers, More preferably, it is 10-45 micrometers, Most preferably, it is 11-40 micrometers. When the thickness is 5 μm or more, the rigidity is improved.

  The thickness (the thickness of one layer) of the layers (A layer, B layer, E layer, etc.) in the base layer is not particularly limited, but is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0. .3 μm or more. Although the upper limit of the said thickness is not specifically limited, 15 micrometers is preferable, More preferably, it is 10 micrometers, More preferably, it is 8 micrometers. 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 is reduced, and the transparency of the shrink film tends to be further improved. In addition, as for the thickness of the layer in a base layer part, all or one part of them may be the same, and you may mutually differ. For example, the outermost layer of the base layer portion may be thinner than the intermediate layer of the base layer portion. In addition, 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, and even more preferably 80% or more. Particularly preferably, it is 90% or more. The upper limit of the ratio may be 100%.

  In the shrink film of the present invention, the ratio of the thickness of the surface layer (total thickness of all surface layers) and the thickness of the base layer [(thickness of the surface layer) :( thickness of the base layer)] is not particularly limited. 2: 1 to 1:10 are preferable, and 1: 1 to 1: 4 are more preferable. When the base layer portion is thicker than 2: 1, the 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 1:10, the rigidity and abrasion resistance of the label are improved.

  The T-type peel strength (in accordance with JIS K 6854-3) of 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, it is 1N or more. The upper limit of the T-type peel strength is not particularly limited, but is preferably 10N or less, more preferably 8N 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. In addition, it is preferable that the T-type peel strength between the surface layer on which the print layer is provided and the B layer is in the above range. Moreover, the said T-type peeling strength is in the shrink film of this invention in the state in which 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 a direction different from one direction) from the viewpoint of exhibiting heat shrinkability. Is preferred. Furthermore, 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, in particular, a film oriented in one direction (uniaxially oriented film) or a film oriented in one direction and a direction orthogonal to one direction (biaxially oriented film) is often used. Films (including films that are stretched primarily in one direction and slightly stretched in a direction perpendicular to the one direction and substantially stretched in one direction) are generally used.

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

  The shrinkage rate of the shrink film of the present invention (when unshrinked) at 100 ° C. for 10 seconds (warm water treatment) in the main shrink direction (sometimes referred to as “thermal shrinkage rate (100 ° C., 10 seconds)”) 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 a direction having the largest thermal shrinkage rate, and is generally a direction mainly stretched, for example, a film stretched substantially in one direction in the width direction. In the case of the width direction.

  In addition, although the thermal contraction rate (100 degreeC, 10 second) of the shrink film (before shrink process) of this invention in the direction orthogonal to the main shrinkage direction is not specifically limited, -5-25% is preferable, More preferably -3 to 20%.

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

  The haze value [based on JIS K 7136, unit:%] of the shrink film of the present invention after 60% thermal shrinkage in the main shrinkage direction is not particularly limited, but is preferably 5% or less, more preferably 4 .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 high shrinkage part.

(Print layer)
The printed 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. In addition, when both outermost layers of a base layer part are B layers, the said printing layer may be provided in one side of the shrink film of this invention, and may be provided in both surfaces.

  The print layer is not particularly limited, and examples thereof include known or commonly used print layers used in shrink labels. Examples of the printing layer include a solvent drying type printing layer formed with a solvent drying type printing ink, an active energy ray curable printing layer formed with an active energy ray curable printing ink, and the like. In addition, examples of the print layer include design print layers (color print layers and the like) such as product names, illustrations, handling precautions, and the like, back print layers formed in a single color such as white, films, Examples thereof include a protective printing layer provided for protecting the printing layer, and a primer printing layer provided for improving the adhesion between the film and the printing layer. Although the said printing layer is not specifically limited, You may be provided only in the single side | surface side of the shrink film of this invention, and may be provided in the both surfaces side of the shrink film of this invention. Moreover, the said printing layer may be provided in the whole surface (surface on the side in which a printing layer is provided) of the shrink film of this invention, and may be provided in part. Furthermore, the printing layer is not particularly limited, but may be a single layer or a multilayer. Further, the printing layer can be provided by a known or common printing method. Especially, it is preferable that the said printing layer is provided by the gravure printing method or the flexographic printing method.

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

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

  As a printed layer, a printed layer containing titanium oxide (especially a printed layer having a high titanium oxide content) is preferable as a label because the back is less transparent. It tends to peel easily (print delamination). However, the shrink label of the present invention can suppress this printing delamination. As a printing layer having high concealability (preventing see-through), a layer having a titanium oxide content of 30 to 85% by weight is preferable, more preferably 40 to 40%, based on the total weight (100% by weight) of the printing layer. 84% by weight, more preferably 50 to 83% by weight. As the binder resin contained in the printing layer containing titanium oxide, acrylic resins and urethane resins are preferable, and acrylic resins are particularly preferable.

  The solvent-dried printing layer, for example, after applying the printing ink produced by mixing the binder resin, 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 is produced, for example, by mixing the monomer component constituting the binder resin, and if necessary, the coloring pigment, solvent, and other additives. After the printing ink is applied using a printing machine, it is dried if necessary, and the monomer component is polymerized and cured by irradiation with active energy rays (for example, ultraviolet rays).

  Although the thickness of the said printing layer is not specifically limited, For example, 0.1-10 micrometers is preferable, More preferably, it is 0.3-5 micrometers. In particular, the thickness of the printing layer having high concealment is preferably 0.5 μm or more, and more preferably 1.0 μm or more.

  Therefore, the printed layer preferably 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, the printed layer is particularly preferably a layer containing an acrylic resin and titanium oxide, having a titanium oxide content of 30 to 85% by weight and a thickness of 0.5 μm or more. When such a printed layer is provided, the delamination of the shrink film is more likely to occur. However, even if the shrink label of the present invention has such a printed layer, delamination does not easily occur.

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

  Although it does not specifically limit as layers other than the shrink film and printing layer of this invention contained in the shrink label of this invention, Other film layers, such as a nonwoven fabric and a foamed sheet, An adhesive layer (Pressure-sensitive adhesive layer, heat sensitive) Adhesive layer, etc.), protective layer, anchor coat layer, primer coat layer, coating layer, antistatic layer, aluminum vapor deposition layer and the like.

  Although the thickness (total thickness) of the shrink label of this invention is not specifically limited, 10-110 micrometers is preferable, More preferably, it is 15-90 micrometers, More preferably, it is 20-80 micrometers.

  The shrink label of the present invention is not particularly limited in the T-type peel strength (in accordance with JIS K 6854-3) of the surface layer and the B layer (B layer adjacent to the surface layer) provided with the printing layer, but 0 0.5N or more is preferable, and 0.6N or more is more preferable. The upper limit of the T-type peel strength is not particularly limited, but is preferably 10N or less, more preferably 8N 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 configuration in which the surface layer provided with the printed layer and the B layer are directly laminated on both sides, the T-type peel strength only on 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 printed shrink label, a back printed shrink label, or a duplex printed shrink label. Among them, it is particularly useful to use it as a back printed shrink label. In the present specification, the front printed label is a label showing printing without passing through the shrink film, and means a label having a design print layer in front of the shrink film when viewing the label. Moreover, a back printed label is a label which shows printing through a shrink film, and means a label which has a design printing layer in the back | inner side rather than a shrink film when seeing a label. Moreover, a double-sided printing label means the label which has a design printing layer on the both surfaces side of a shrink film.

  1 and 2 are schematic views (partial cross-sectional views) showing a preferred example of the shrink label of the present invention. The shrink label 3 of the present invention shown in FIG. 1 includes the shrink film 1 of the present invention and a printing layer 2 provided on one side of the shrink film 1 of the present invention. The shrink film 1 of the present invention includes a base layer portion 12 and a surface layer 11 provided on each side of the base layer portion 12. The base layer portion 12 has three layers, and the outermost layer (the layer in contact with the surface layer 11) is a B layer 12a, and the B layer 12a and the A layer 12b are alternately laminated in total three layers. ing. The surface layer 11 on which the printing layer 2 is provided 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 that is the outermost layer of the base layer portion are directly laminated. An A layer 12b is interposed between the B layers 12a.

  The shrink label 3 of the present invention shown in FIG. 2 includes the shrink film 1 of the present invention and a printing layer 2 provided on one side of the shrink film 1 of the present invention. The shrink film 1 of the present invention has a surface layer 11 and a base layer portion 12, and the base layer portion 12 has nine layers, and its outermost layer (a layer in contact with the surface layer 11) is a B layer 12a, and a B layer A total of nine layers 12a and A layers 12b are alternately stacked. Also in FIG. 2, the surface layer 11 and the base layer portion 12 are directly laminated without interposing other layers, and the surface layer 11 and the B layer 12a that is the outermost layer of the base layer portion 12 are interposing other layers. There is no direct lamination. 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 includes two surface layers mainly composed of a polyester-based resin, and a layer (A layer) mainly composed of a polystyrene-based resin between the two surface layers, and three or more layers. A base layer portion having a multilayer structure. Thereby, rigidity can be made high, maintaining the thickness of a shrink film, it is excellent in heat shrinkability, and it is excellent in shrink finish. Moreover, since the base layer portion has a multi-layer structure, the thickness of each layer can be reduced, and thus the transparency is also excellent. In the present invention, the outermost layer of the base layer part directly laminated with the surface layer provided with the printing layer is a layer containing a specific amount of polyester resin, styrene elastomer, and polystyrene resin other than styrene elastomer (layer B). ) To improve the interlaminar strength between the surface layer and the base layer, thereby making it difficult for delamination between the surface layer and the base layer. Furthermore, even if the printing layer is a plurality of printing layers or a printing layer formed with a printing ink containing a highly soluble solvent, delamination between the surface layer and the base layer portion hardly occurs.

[Production method of shrink label of the present invention]
The shrink label of this invention is obtained by the manufacturing method which includes the process (film preparation process) which produces the shrink film of this invention, and a printing layer formation process at least. Moreover, other processes (processes other than the said film preparation process), such as the process of forming layers other than the shrink film of this invention, 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. Among these, the melt film forming method (particularly, the T-die method) is preferable. As a lamination method, a conventional method such as a co-extrusion method (feed block method, multi-manifold method, etc.), a dry lamination method, or the like can be used. Among these, the coextrusion method is preferable, and the feed block method is preferable. Further, when the base layer portion has four or more layers, the base layer portion should be further multilayered by using a layer multiplier, in particular, using a combination of a feed block and a layer multiplier. Is preferred. The layer multiplier is a device that multi-layers film layers. The method of multilayering the film layer with the layer multiplier is not particularly limited, and examples thereof include a method of dividing the film layer in the width direction and then laminating the divided film layer in the thickness direction. In the present specification, the “layer multiplier” may be simply referred to as “multiplier”. The above multiplier can be obtained from, for example, EDI and Crawlen.

  A specific example of the coextrusion method (feed block method) will be described below. For example, the raw material for forming the base layer and the raw material for forming the surface layer are respectively charged into a plurality of extruders each set to a predetermined temperature, and co-extruded from a T die, a circular die, or the like. At this time, it is preferable to use a manifold or a feed block to obtain a predetermined laminated structure. In addition, when a base layer part has four or more layers, it is preferable to use a combination of a feed block and a multiplier to make the base layer part multi-layered to have a predetermined laminated structure. Moreover, you may adjust supply_amount | feed_rate using a gear pump as needed. Furthermore, it is preferable to remove foreign substances using a filter because film tearing can be reduced. In addition, although extrusion temperature changes also with the kind of raw material to be used and is not specifically limited, 150-250 degreeC is preferable. Moreover, it is preferable that the temperature of a junction part or die | dye shall be 200-250 degreeC. A laminated unstretched film (sheet) can be obtained by quenching the coextruded polymer using a cooling drum or the like.

  Although the manufacturing method of the shrink film of the present invention is not particularly limited, when the base layer portion is formed from the A layer and the B layer, the raw material constituting the A layer (sometimes referred to as “raw material (a)”), 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 each melted (or melt kneaded). A first stage in which the raw material (a) and the raw material (b) melted (or melt-kneaded) in the first stage are laminated, and further laminated as necessary to form a laminated body. It is preferable to include at least a third stage of laminating the raw material (c) melted in the first stage on both sides of the laminate formed in the second stage. Furthermore, other stages (stages other than the first stage, the second stage, and the third stage) may be included. The other stage is, for example, before the first stage, after the third stage, between the first stage and the second stage, between the second stage and the third stage, etc. It may be provided in the position.

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

  In the second stage, the laminate obtained by laminating the raw material (a) and the raw material (b) melted in the first stage and further multilayered is not particularly limited. The raw material (a) and the raw material (b) thus formed can be sequentially laminated or simultaneously laminated (co-extruded) using a feed block. In addition, the laminated body may be a laminated body formed by further multilayering the laminated body formed by sequentially laminating or coextrusion using the multiplier. The lamination is not particularly limited, but it is preferable to use a combination of a feed block and a multiplier. Each of the above feed blocks and multipliers may use only 1 or 2 or more. In the above laminate, the total number of layers formed from the raw material (a) and the number of layers formed from the raw material (b) is preferably 3 to 65 layers, more preferably 5 to 33 layers, still more preferably. Is 9 to 33 layers. The laminate obtained in the second stage forms the base layer portion of the shrink film of the present invention.

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

  In addition, in the second stage, the laminated body obtained by laminating the raw material (a) and the raw material (b) and further multilayered is specifically the raw material melted in the first stage, for example. (A) and the raw material (b) are extruded using a feed block to produce a laminate (sometimes referred to as “laminated body 3”) having a configuration of [raw material (a) / raw material (b)], Next, the laminate 3 is laminated as a unit 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, if the said laminated body 4 is followed from the reverse, [raw material (b) / raw material (a) / raw material (b) / raw material (a) /.../ raw material (b) / raw material (a)]. It is also a laminate having a structure.

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

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

  [Raw material (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)] has the structure [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 practice, the interface of [B layer / B layer] formed from [raw material (b) / raw material (b)] obtained by laminating the same material of the laminate 2 becomes invisible. Since it becomes one B layer, it becomes a base layer portion having a structure of [B layer / A layer / B layer / A layer /... / B layer / A layer / B layer]. In addition, when the surface layer and the outermost layer (resin layer) of the base layer portion are layers made of the same resin composition, the interface becomes invisible, and the surface layer and the outermost layer of the base layer portion are separated. It becomes one layer (surface layer).

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

  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 simultaneously, or biaxial stretching may be sequentially performed. More specifically, for example, after stretching at a stretching temperature of 65 to 100 ° C. and a stretching ratio of 1.05 to 1.50 in the longitudinal direction by a roll method, stretching at a stretching temperature of 70 to 100 ° C. in the width direction by a tenter method. The film is stretched at a magnification of 3 to 8 times (preferably 4 to 7 times).

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

  In the above film production process, the example in which the base layer portion is formed only from the A layer and the B layer has been described. Can be produced.

(Print layer forming process)
In the printing layer forming step, the printing layer can be formed by applying 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, known and usual methods can be used, and among them, gravure printing, flexographic printing, and digital printing are preferable. In addition, when the applied printing ink is dried or dried and solidified by heating or the like, a general heating device that can be heated 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 the design printing layer, generally, the printing ink is applied a plurality of times for each color to form a printing layer that is a multilayer.

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

  As said solvent, the water normally used for the printing ink used for gravure printing, flexographic printing, etc., an organic solvent, etc. can be used. Examples of the organic solvent include esters such as acetate (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; 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 . The solvent can be removed by drying after applying the printing ink to the shrink film of the present invention. The solvent includes the meaning of “dispersion medium”.

[Cylinder shrink label]
The shrink label of the present invention is, for example, a cylindrical shrink label of a type in which both ends of the label are sealed with a solvent or an adhesive and attached to the container, and one end of the label is attached to the container, and the label is wound After that, it can be used as a wrapping type shrink label in which the other end is overlapped with one end to form a cylinder. 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, the cylindrical shrink label using the shrink label of the present invention may be referred to as “the cylindrical shrink label of the present invention”.

  An example of a cylindrical shrink label which is a preferred embodiment of the shrink label of the present invention will be described with reference to FIGS. 3 and 4. The cylindrical shrink label 4 of the present invention shown in FIG. 3 is formed into a cylindrical shape by superposing the other end on the outside of one end of the shrink label of the present invention formed in a rectangular shape. This is a cylindrical body in which a seal part 41 is formed by joining the outer surface of the part with a solvent or an adhesive. The cylindrical shrink label of the present invention includes the shrink film of the present invention, and the shrink film of the present invention is at least oriented in the circumferential direction D of the cylindrical shrink label of the present invention and can be thermally contracted in that direction. In addition, it is preferable that the cylindrical shrink label of this invention is mounted | worn so that the circumferential direction may turn into a main contraction direction. Moreover, even if it is a winding type shrink label, it is preferable to make it a cylinder shape so that a circumferential direction may turn into a main contraction direction (namely, extending direction).

  4 is a cross-sectional view taken along the line IV-IV ′ in FIG. 3, that is, an enlarged view of the main part in the vicinity of the seal part of the tubular shrink label 4 of the present invention. In the seal part 41, both ends of the shrink label are solvent or Bonded with an adhesive 53. Specifically, the shrink label of the present invention has a design printing layer in a region excluding the region of a predetermined width from the other end of one surface (the surface on the cylindrical inner surface side) of the shrink film 1 of the present invention. 52 is formed, and the back printed layer 51 is formed over substantially the entire region excluding the region of a predetermined width from the end of the other end of one surface of the shrink film 1 of the present invention so as to cover the design printed layer 52. Has been. For this reason, in the shrink label of the present invention, the region having a predetermined width from the end of the other end is not formed with the back print layer 51 and the design print layer 52, and the shrink film 1 of the present invention is exposed, and the film An exposed surface is formed, and the seal portion 41 has a film exposed surface formed on the inner surface side of the other end portion of the shrink label of the present invention and an outer surface (film exposed surface) of one end portion by a solvent or an adhesive 53. It is joined. That is, in the seal part 41, it is preferable that the shrink films 1 of the present invention are joined together with a solvent or an adhesive 53. In addition, even if it has a printing layer, such as a back surface printing layer and a design printing layer, the part which is not joined among the said both ends may have a printing layer, since there is no influence on adhesiveness.

  In the cylindrical shrink label 4 of the present invention in FIG. 4, one end portion extends to a position where the end overlaps the back print layer 51 at the other end portion, and the back print layer 51 at the one end portion and the other end portion. The area | region which mutually overlaps via the shrink film 1 of this invention is formed. For this reason, there is no region where the back print layer 51 does not exist in the thickness direction. The cylindrical shrink label of the present invention may have a structure as shown in FIG. 4 that overlaps the end printed on one end and the back printed layer on the other end (overlapping in the thickness direction, that is, overlapping in the surface spreading direction). The end of the one end and the other end are not extended to a region where the end of the one end overlaps with the film exposed surface of the other end, and the end of the one end does not extend to the position overlapping the back print layer on the other end. The structure which does not overlap with the back printing layer of the side may be sufficient.

  Although the width | variety of the said seal | sticker part is not specifically limited, 0.2-10 mm is preferable, More preferably, it is 0.3-5 mm, More preferably, it is 0.4-2 mm.

(Manufacturing method of cylindrical shrink label)
Although the manufacturing method of the cylindrical shrink label of this invention is not specifically limited, For example, it is as follows. The long 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 continuous in the long direction (longitudinal direction). This long label is formed in a cylindrical shape by overlapping so that the heat shrinkable direction (that is, the shrinkage direction of the shrink film) is the circumferential direction, and the other end is outside the one end. Then, the overlapped portion is sealed in a band shape with a predetermined width, and both ends are joined to obtain a continuous continuous label body (a long cylindrical shrink label). By cutting the long cylindrical shrink label in the circumferential direction, one cylindrical shrink label (the cylindrical shrink label of the present invention) having a predetermined length in the height direction can be obtained. In the case of providing a perforation for label excision, a conventional method (for example, a method of pressing a disk-shaped blade having a cut portion and a non-cut portion repeatedly formed around it, a method using a laser, etc.) Can be applied. The process of perforating can be suitably selected after providing the printing layer or before or after the process of processing into a cylindrical shape.

[Container with label]
Although the shrink label of this invention is not specifically limited, It mounts | wears with a container and is used as a labeled container. In addition, the shrink label of this invention may be used for adherends other than a container. For example, the shrink label of the present invention (particularly, the cylindrical shrink label) is placed around the container so that the shrink label of the present invention is in a cylindrical shape, and attached to the container by heat shrinking. A container (a labeled container having the shrink label of the present invention) is obtained. Examples of the containers include soft drink bottles such as PET bottles, milk bottles for home delivery, food containers such as seasonings, bottles for alcoholic beverages, pharmaceutical containers, containers for chemical products such as detergents and sprays, and toiletries. Containers, cup noodle containers and the like are included. Although it does not specifically limit as a shape of the said container, For example, various shapes, such as bottle types, such as cylindrical shape and a square shape, and a cup type, are mentioned. The material of the container is not particularly limited, and examples thereof include plastics such as PET, glass, and metals. In addition, the container equipped with the shrink label of the present invention may be referred to as “the labeled container of the present invention”.

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

  EXAMPLES Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

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

Example 1
(material)
100% by weight of polyester-based resin B (manufactured by Eastman Chemical, trade name “EMBRACE LV”, Tg: 69 ° C.) was used as a raw material constituting the surface layer (surface layer raw material).
As a raw material constituting the resin layer (A) (raw material for the resin layer (A)), a polystyrene-based resin A (manufactured by Stylus Lucon, trade name “Styrolux T”, content of structural unit derived from butadiene: 25 weight %) Was used in an amount of 70% by weight, and polystyrene resin B (manufactured by Stylorusion, trade name “Styrolox S”, content of structural unit derived from butadiene: 12% by weight) was used in an amount of 30% by weight.
As raw materials constituting the resin layer (B) (raw material for the resin layer (B)), 54% by weight of polyester resin B, 27% by weight of polystyrene resin A, 12% by weight of polystyrene resin B, styrene elastomer 7% by weight of A (Asahi Kasei Co., Ltd., trade name “Tufprene 126S”) was used.

(Shrink film)
The raw material for the resin layer (A) in the extruder x heated to 220 ° C., the raw material for the resin layer (B) in the extruder y heated to 220 ° C., and the raw material for the surface layer in the extruder z heated to 250 ° C. Was introduced. Melt extrusion was performed using the above three extruders. Using a laminating apparatus in which a molten raw material for the resin layer (A) and a molten raw material for the resin layer (B) are combined with a feed block of a combination of two types and three layers and a four-part multiplier, the resin layer (B) Raw material / resin layer (A) Raw material / Resin layer (B) raw material 2 types 3 layers are divided, merged, and laminated as one repeating unit to obtain a laminate (I) (2 types 3) 4 layers are laminated (repetition number is 4)), and the melted raw material for the surface layer is merged and laminated on both sides of the laminate (I) using a feed block, and the laminate (II ). Furthermore, after the laminate (II) was extruded from a T-die, it was rapidly cooled on a casting drum cooled to 25 ° C. to obtain a laminated unstretched film in which surface layers were provided on both sides of the base layer portion, respectively. . The outermost layers on both sides of the base layer portion are resin layers (B).

  Next, the laminated unstretched film is stretched 6 times tenter at 85 ° C. in the width direction, so that the stretched film (shrink film) is mainly stretched uniaxially in the width direction and has heat shrinkability in the direction. Got the body. In Example 1, the resin layer (A) corresponds to the A layer, and the resin layer (B) corresponds to the B layer.

(Cylinder shrink label)
With respect to the long body of the shrink film obtained above, binder resin (trade name “Dianar BR-64”, acrylic resin, manufactured by Mitsubishi Rayon Co., Ltd.) 10% by weight, pigment (trade name “JR-”) 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. Applying, drying and solidifying using the trade name “GRAVO PROOF MINI” (trade name, manufactured by quotient gravure), forming a white back print layer (thickness: 3 μm) on the entire surface other than the part to be the seal part. A scale was obtained. Next, after slitting the long body of the shrink label so as to have a predetermined width, one end and the other end are overlapped to form a cylinder so that the width direction is the circumferential direction. The shrink film surfaces of the part were sealed with a solvent to obtain a cylindrical long body of a shrink label. Furthermore, the cylindrical long body (label continuous body) of the shrink label was cut into individual label sizes to obtain a cylindrical shrink label.

Examples 2 to 5, Comparative Examples 1 and 2
As shown in Table 1, the shrinkage film and the cylindrical shrinkage were made in the same manner as in Example 1 by changing 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. 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. As the polyester resin A, a trade name “EMBRACE” (manufactured by Eastman Chemical, Tg: 71 ° C.) was used.

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

(1) Peel strength (shrink film)
About the shrink film obtained by the Example and the comparative example, the T-type peeling strength between the resin layer (B) which is the outermost layer of a surface layer and a base layer part was measured with the following method.
From the shrink film, a rectangular sample with a width of 15 mm in the longitudinal direction of the shrink film (shrink film forming direction) and a length of 200 mm in the width direction of the shrink film (direction perpendicular to the longitudinal direction) Film width direction) × width 15 mm (longitudinal direction of shrink film)]. 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.
With the long side direction of the sample as the measurement direction, a T-type peel test (based on JIS K 6854-3) was performed under the following conditions to measure the peel load between the layers.
The average value of the peel load was defined as T-type peel strength (N).
(Measurement condition)
Measuring device: Autograph manufactured by Shimadzu Corporation (AG-IS: load cell type 500N)
Temperature and humidity: Temperature 23 ± 2 ℃, humidity 50 ± 5% RH
Initial chuck interval: 40 mm
Sample width: 15mm
Number of tests: 3 times Tensile speed: 200 mm / min Stroke: 150 mm
First half deletion range: 50mm
Sensitivity: 1

(2) Peel strength (shrink label)
Except that the cylindrical shrink labels obtained in the examples and comparative examples were used, the surface layer and the base layer on the side where the printed layer was provided were the same as in “(1) Peel strength (clear)”. The T-type peel strength between the outer resin layers (B) 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 printed layer was formed. . In particular, the shrink labels obtained in Examples 1 to 4 were also excellent in transparency (particularly transparency after 60% shrinkage). On the other hand, when the resin layer (B) did not contain a styrene elastomer (Comparative Example 1) or when the resin layer (B) did not contain a polyester resin (Comparative Example 2), the interlayer strength was low.

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

Claims (5)

A shrink label having a shrink film and a printed layer provided on at least one surface of the shrink film,
The shrink film has a base layer part and surface layers provided on both sides of the base layer part,
The surface layers provided on both sides are layers in which the content of the polyester resin is 50% by weight or more,
The base layer portion includes 3 to 65 layers, and the layer in the base layer portion is a layer (A layer) having a polystyrene resin content of 50% by weight or more and a polyester resin content of 30% by weight. A layer (B layer) having a content of greater than or equal to 92% and less than or equal to 92% by weight, a styrene elastomer content of 3 to 30% by weight, and a polystyrene resin content other than the styrene elastomer of 5% to less than 67% by weight And at least one of the outermost layers of the base layer portion is a B layer,
A shrink label comprising at least a structure in which a surface layer provided with the printing layer and a B layer which is an outermost layer of the base layer portion are directly laminated.   The shrink label of Claim 1 whose thickness of the surface layer in which the said printing layer was provided is 5-15 micrometers.   The shrink label according to claim 1 or 2, wherein the base layer portion includes 5 to 65 layers.   The shrink label of any one of Claims 1-3 whose styrene-type elastomer in the said B layer is a styrene-diene-type copolymer elastomer.   The shrink label according to any one of claims 1 to 4, wherein the printed layer includes 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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