JP6345453B2 - Shrink label - Google Patents

Description

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

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

  As the shrink label, for example, a shrink label comprising a base film (1) in which an outer surface layer (B1) made of a polyester resin is laminated on both sides of an intermediate layer (A1) made of a polystyrene resin. The polyester-based resin contains 1,4-cyclohexanedimethanol as a diol component, and the outer surface layer (B1) is directly laminated on both sides of the intermediate layer (A1). A shrink label is known (see Patent Document 1). In the shrink label, since the base film is formed by directly laminating an outer surface layer made of a polyester resin on both sides of an intermediate layer made of a polystyrene resin, shrinkage may be inhibited by the adhesive layer. In addition, the advantages of both polystyrene resin and polyester resin, that is, excellent heat resistance, solvent resistance, and low temperature shrinkability, and the process of providing an adhesive layer can be reduced, and a simple method such as a three-layer coextrusion method. Since the base film can be manufactured, it can be easily manufactured at low cost.

  Such a shrink label is used as a tubular shrink label so that it can be easily separated from the bottle even at the consumer stage for recycling the bottle after being used in a container such as a PET bottle. What is easy to cut off a label in the vertical direction (direction orthogonal to the circumferential direction) of a label is preferable. As a method for making the label easy to cut off, for example, a film made of a material having good tearability, a thin film thickness, and a perforation in the longitudinal direction of the label are known.

JP 2002-351332 A

  However, to improve the tearability of the cylindrical shrink label in the vertical direction by the above method in order to make it easy to cut off the label, for example, when the container with the label (labeled container) falls, the drop There was a problem that the label was easy to tear due to the impact of. In particular, when the label is perforated, the ease of cutting off the label is further improved. On the other hand, the problem that the label is easily torn from the perforation and is easily broken by the impact of dropping is even more remarkable. It was. That is, there is a correlation between the tearability of the label and the difficulty of tearing the label when dropped (label drop resistance), and the thickness of the film (or label) and the perforation size when the perforation is inserted It was only possible to adjust the balance between the tearability of the label and the drop resistance of the label. Therefore, the present situation is that there is a demand for a shrink label having both excellent label drop resistance and tearability.

  That is, an object of the present invention is to provide a shrink label excellent in label drop resistance and tearability.

  This invention is a shrink label which has a shrink film, Comprising: The said shrink film has the base layer part which contains 5 to 65 layers, and the surface layer provided in the both surfaces side of the said base layer part, The said base layer part Has an interface formed by adjoining the layers, and three or more of the interfaces have an interface (interface) having a T-type peel strength lower than the T-type peel strength of the surface layer and the base layer portion. (L)) is provided.

  Furthermore, in the present invention, the base layer portion has at least a resin layer (A) and a resin layer (B) as the layers, and the resin is a main component of each of the resin layer (A) and the resin layer (B). Is a polyester resin and a polystyrene resin, a polyester resin and a polyolefin resin, or a polystyrene resin and a polyolefin resin, and the resin layer (A) and the resin layer (B) are formed adjacent to each other. The shrink label is provided, wherein the interface has an interface (interface [A / B]), and three or more of the interfaces [A / B] are the interfaces (L).

  Furthermore, the present invention provides the shrink label, wherein the combination of the outermost layer of the base layer portion and the surface layer is a combination of layers mainly composed of the same resin.

  Furthermore, this invention provides the said shrink label whose thickness (1 layer thickness) of the said layer in the said base layer part is 0.2-10 micrometers.

  Since the shrink label of the present invention has the above-mentioned specific configuration, it is excellent in label drop resistance and tearability. Therefore, when a labeled container is dropped, the label is not easily broken by the impact of the drop. Consciously, the label is easy to cut off and can be easily separated from the container.

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

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

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

(Surface layer)
The surface layer in the shrink film of the present invention is a layer (resin layer) provided on each side of the base layer.

  The surface layer is not particularly limited as long as it is a resin layer having shrinkage characteristics and capable of forming a print layer. The resin contained in the surface layer is not particularly limited. For example, a thermoplastic resin such as a polyester resin, a polystyrene resin, a polyolefin resin, a vinyl chloride resin, a polycarbonate resin, a polyamide resin, or a thermoplastic elastomer. Etc. Of these, polyester resins and polystyrene resins are preferable. As for the said thermoplastic resin, only 1 type may be used and 2 or more types may be used.

  In the present specification, as the polyester-based resin, for example, a polyester composed of a dicarboxylic acid component and a diol component as essential components (that is, a structural unit (structural unit) derived from dicarboxylic acid and a structural unit derived from diol). Polyester containing at least), polylactic acid-based polymers, 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 an alicyclic dicarboxylic acid 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 diol may be used alone or in combination of two or more.

  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 polyester resins, aromatic polyester resins are preferable from the viewpoints of rigidity, drop resistance, shrinkage characteristics, wear resistance, and heat resistance. 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.

  The aromatic polyester-based resin is not particularly limited, but it is not composed of a single repeating unit, but includes a modifying component (copolymerization component) from the viewpoints of stretch properties, shrinkage properties, and tearability of the label. A modified aromatic polyester resin is preferred. 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 a 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. Further, CHDM is particularly preferable in order to more effectively suppress delamination during shrink processing.

  The aromatic polyester-based resin is not particularly limited, but specifically, terephthalic acid was used as the dicarboxylic acid component and ethylene glycol (EG) was used as the diol component from the viewpoint of shrinkage characteristics and label tearability. Polyethylene terephthalate (PET): A modified aromatic polyester resin ("CHDM") using terephthalic acid as the dicarboxylic acid component, ethylene glycol as the diol component, and 1,4-cyclohexanedimethanol (CHDM) as the copolymerization component. Modified fragrance using terephthalic acid as the dicarboxylic acid component, ethylene glycol as the main component, and 2,2-dialkyl-1,3-propanediol as the copolymer component. Group polyester resin ("2, - sometimes referred to as dialkyl-1,3-propanediol copolymer PET ") are preferred. Among the 2,2-dialkyl-1,3-propanediol copolymerized PET, in particular, terephthalic acid is used as the dicarboxylic acid component, ethylene glycol is the main component, and neopentyl glycol (NPG) is the copolymerized component as the diol component. The modified aromatic polyester-based resin used as (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 from the viewpoint of optimizing the thermal deformation behavior of the layer and reducing delamination during shrink processing. It is 15 mol% or more (for example, 15 to 40 mol%). Among them, for example, in the case of CHDM copolymerized PET, the ratio of CHDM is preferably 10 to 30 mol% (EG is 70 to 90 mol%), more preferably 12 to 25 mol% (EG is 75%) in all diol components. ~ 88 mol%). 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 10-30 mol% (EG is 70-90 mol%) in a diol component is preferable. Further, a part of the EG component (preferably 1 to 30 mol% in the total diol component) may be replaced with diethylene glycol.

  The aromatic polyester resin is not particularly limited, but is preferably a substantially amorphous aromatic polyester resin, and 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. Thereby, the formability of the layer at the time of an extrusion process becomes favorable, and also the shrinkage | contraction characteristic of a shrink label can be improved. In addition, the tearability of the label can be improved.

  The degree of crystallinity of the polyester resin measured by the differential scanning calorimetry (DSC) method (measured at a heating rate of 10 ° C./min) is not particularly limited, but is preferably 15% or less, more preferably 10%. It is as follows. Further, the polyester-based resin is most preferably one that exhibits almost no melting point (melting peak) when measured by the DSC method (that is, a crystallinity of 0%). The crystallinity can be calculated from the 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 30,000 to 90,000, and still more preferably 30,000 to 10,000, from the viewpoint of melting behavior and shrinkage behavior. 80,000. In the case of 2,2-dialkyl-1,3-propanediol copolymerized PET, 50,000 to 70,000 is more preferable.

  Although the glass transition temperature (Tg) of the said polyester-type resin is not specifically limited, 60-80 degreeC is preferable from a viewpoint of an extending | stretching characteristic and a shrinkage | contraction characteristic, More preferably, it is 60-75 degreeC. 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. “Belpet MGG200” (2,2-dialkyl-1,3-propanediol copolymerized PET) manufactured by Bellpet Products, “Belpet E02” (NPG copolymerized PET) manufactured by Bell Polyester Products, Inc. is 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, , Copolymers with other hydroxycarboxylic acids, lactones, dicarboxylic acids, diols, and the like). 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 illustrated and demonstrated as a component which comprises the above-mentioned polyester-type resin, etc. 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 monomers constituting the polylactic acid polymer is not particularly limited, but is, for example, 50 mol% or more, preferably 65 mol% or more, more 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 a suitable 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.

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

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

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

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

  The diene is not particularly limited, but is preferably a conjugated diene, such as 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, 1, Examples include 3-pentadiene, 1,3-hexadiene, chloroprene. Among these, 1,3-butadiene is particularly preferable from the viewpoint of stretching characteristics and shrinkage characteristics. 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 random copolymers, block copolymers, and graft copolymers. Among these, block copolymers are preferable, and examples thereof include styrene block (S) -diene block (D) type, SDS type, DSD type, SSDSD type, and the like. .

  Examples of the styrene-diene copolymer block copolymer (styrene-diene block copolymer) include styrene-butadiene block copolymers such as styrene-butadiene-styrene block copolymer (SBS), styrene, and the like. -Styrene-isoprene block copolymers such as isoprene-styrene block copolymer (SIS), and styrene-butadiene-isoprene block copolymers such as styrene-butadiene / isoprene-styrene block copolymer (SBIS). Of these, styrene-butadiene block copolymers are preferred. 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 alternately a styrene block obtained by polymerizing only a styrene monomer and a butadiene block obtained by polymerizing only butadiene. A styrene-butadiene block copolymer having styrene blocks at both ends, such as a butadiene-styrene block copolymer (SBS) and a styrene-butadiene-styrene-butadiene-styrene block copolymer (SBSBS); Styrene block such as polymer (SB), styrene-butadiene-styrene-butadiene copolymer (SBSB) and styrene-butadiene block copolymer having a butadiene block at the end; butadiene-styrene-butadiene copolymer (BSB), Diene - styrene - butadiene - styrene - butadiene block copolymer, and the like - styrene with butadiene copolymer (BSBSB) butadiene block such at both ends. Among these, a styrene-butadiene block copolymer having a styrene block at both ends is preferable, and SBS is more preferable. In addition, these styrene-butadiene copolymers may use only 1 type, and may use 2 or more types.

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

  When the polystyrene resin is a styrene-diene copolymer, the styrene-diene copolymer is not particularly limited, but the content of structural units derived from the styrene monomer is included in the layer. It is preferably 50 to 95% by weight, more preferably 60 to 90% by weight, still more preferably 70 to 90% by weight based on the total weight (100% by weight) of all the styrene-diene copolymers. On the other hand, the content of the structural unit derived from diene is preferably 5 to 50% by weight, more preferably 10 to 10% by weight based on the total weight (100% by weight) of all the styrene-diene copolymers in the layer. 40% by weight, more preferably 10 to 30% by weight.

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

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

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

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

  The modified polystyrene resin is a polystyrene resin in which a polar group is introduced using a polystyrene resin as a main chain skeleton. The polar group is not particularly limited, and examples thereof include an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, a carboxylic acid chloride group, a carboxylic acid amide group, a carboxylic acid group, a sulfonic acid group, and a sulfonic acid ester group. Sulfonic acid chloride group, sulfonic acid amide group, sulfonic acid group, isocyanate group, epoxy group, amino group, imide group, oxazoline group, hydroxyl group and the like. Among these, an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, and an epoxy group are preferable, and a maleic anhydride group and an epoxy group are more preferable. The modified polystyrene-based resin has a polar group that has high affinity or can react with the polyester-based resin and is compatible with the polystyrene-based resin. Adhesiveness at room temperature with a layer mainly composed of a resin is increased. As for the said polar group, only 1 type may be used and 2 or more types may be used.

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

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

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

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

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

  Among the polystyrene resins, styrene-diene copolymers are preferable, more preferably styrene-butadiene copolymers, still more preferably styrene-butadiene block copolymers, and particularly preferably styrene blocks at both ends. Styrene-butadiene block copolymer, most preferably SBS.

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

  Examples of the polyolefin resin include a polymer composed of ethylene as an essential monomer component (polyethylene resin), a polymer composed of propylene as an essential monomer component (polypropylene resin), and an ionomer. And amorphous cyclic olefin-based polymers. Only 1 type may be used for the said polyolefin resin, and 2 or more types may be used for it.

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

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

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

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

Examples of the polyethylene resin include low density polyethylene (LDPE) and linear low density polyethylene (LLDPE). The LDPE refers to polyethylene having a low density of about 0.850 to 0.945 g / cm ³ which contains at least a structural unit derived from ethylene and is produced by a high pressure method. The LLDPE refers to a low-density polyethylene of about 0.850 to 0.945 g / cm ³ having at least a structural unit derived from ethylene, produced by a medium / low pressure method, and having a short chain branch.

  Content of the structural unit derived from ethylene in the polyethylene resin (100 wt%), that is, content of ethylene in all monomer components (100 wt%) constituting the polyethylene resin is particularly limited. However, it is preferably 80% by weight or more, more preferably 85% by weight or more, still more preferably 90% by weight or more, and the upper limit is 100% by weight, 99% by weight, 98% by weight, or 95% by weight. Also good. Further, the content of structural units derived from the α-olefin in the ethylene-α-olefin copolymer (100% by weight), that is, all monomer components constituting the ethylene-α-olefin copolymer ( The content of α-olefin in (100 wt%) is not particularly limited, but is preferably 1 to 20 wt%, more preferably 2 to 15 wt%, and still more preferably 5 to 10 wt%.

The density of the polyethylene resin is not particularly limited, but is preferably 0.800 g / cm ³ or more, more preferably 0.850 g / cm ³ or more, more preferably 0.870 g / cm ³ or more, and particularly preferably 0. It is 890 g / cm ³ or more. Although the upper limit of the said density is not specifically limited, 0.950 g / cm < ³ > is preferable, More preferably, it is 0.935 g / cm < ³ >. The melt flow rate (MFR) (temperature 190 ° C., load 2.16 kg) of the polyethylene resin is not particularly limited, but is preferably 1 to 30 g / 10 minutes from the viewpoint of melt extrusion suitability and productivity. Preferably it is 1-10 g / 10min.

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

  As the polyethylene-based resin, commercially available products may be used. For example, “Umerit 4540F”, “Umerit 3540F”, “Umerit 2540F”, “Umerit 1540F”, “Umerit 0540F”, “Umerit 5540F”, “ "Umerit 2040FC", "Umerit 0520F", "Umerit 1520F", "Umerit 0520F", "Umerit 715FT", made by Prime Polymer Co., Ltd., "Evolue SP1520", "Evolue SP2040" (and above, metallocene catalyst LLDPE), Japan “Kernel KF260T”, “Kernel KF360T”, “Kernel KF380”, “Kernel KS340T” manufactured by Polyethylene Co., Ltd. (above, metallocene catalyst ethylene-α-olefin copolymer) Combined), “F234” (LDPE) manufactured by Ube Maruzen Polyethylene Co., Ltd., “V206” manufactured by Ube Maruzen Polyethylene Co., Ltd., “Novatech EVA Series” manufactured by Nippon Polyethylene Co., Ltd. It is.

  The polypropylene resin is not particularly limited. For example, a propylene homopolymer (homopolypropylene), a copolymer composed of propylene and one or more olefins (olefins other than propylene) as essential monomer components. Examples thereof include a blend (propylene copolymer). As the propylene copolymer, among them, a copolymer composed of propylene and one or more α-olefins as essential monomer components (propylene-α-olefin copolymer) is preferable. The propylene copolymer is a copolymer containing at least a structural unit derived from propylene and a structural unit derived from olefin in a molecule (in one molecule). The propylene-α-olefin copolymer is a copolymer containing at least a structural unit derived from propylene and a structural unit derived from α-olefin in the molecule (in one molecule). Examples of the α-olefin used as a copolymerization component of the propylene-α-olefin copolymer include ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-heptene. , 1-octene, 1-nonene, 1-decene and other C2-C20 α-olefins (excluding propylene). Only 1 type may be used for the said alpha olefin, and 2 or more types may be used for it. The propylene copolymer (propylene-α-olefin copolymer or the like) may be a block copolymer, a random copolymer, or a graft copolymer.

  The propylene copolymer is not particularly limited, but the content of the structural unit derived from propylene is preferably 50% by weight or more based on the total weight (100% by weight) of the propylene copolymer, Preferably it is 70 weight% or more, More preferably, it is 80 weight% or more.

  Among the above, the propylene copolymer is particularly preferably a propylene-ethylene copolymer. In the propylene-ethylene copolymer, the ratio of ethylene to propylene is, for example, the former / the latter (weight ratio) = 1/99 to 30/70 (preferably 2/98 to 25/75, more preferably 5/95. It can be selected from the range of about 20/80). The propylene-ethylene copolymer may be in any form of a block copolymer, a random copolymer, and a graft copolymer, and an α-olefin other than ethylene and propylene is further copolymerized. Also good. Moreover, as said propylene copolymer (especially propylene-ethylene copolymer), a thing with an isotactic index of 90% or more is preferable from a viewpoint of low-temperature shrinkage | contraction property and the elasticity of a shrink label.

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

Although the density of the said polypropylene resin is not specifically limited, 0.800 g / cm < ³ > or more is preferable, More preferably, it is 0.850 g / cm < ³ > or more. Although the upper limit of the said density is not specifically limited, 0.950 g / cm < ³ > is preferable.

  Commercially available products may be used as the polypropylene resin, such as “Wintech WFX6”, “Wintech 1987FC” (metallocene catalyst-based propylene-ethylene random copolymer) manufactured by Nippon Polypro Co., Ltd., Mitsubishi Chemical ( "Zeras # 7000" and "Zeras # 5000" manufactured by Co., Ltd., "Vistamaxx 3020FL" (polypropylene resin) manufactured by ExxonMobil Chemical Co., etc. are available on the market.

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

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

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

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

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

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

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

  Although the said surface layer is not specifically limited, The layer which has a thermoplastic resin as a main component is especially preferable. The thermoplastic resin as the main component is not particularly limited, but is preferably a polyester resin, a polystyrene resin, a polyethylene resin, a polypropylene resin, or an amorphous cyclic olefin polymer, more preferably a polyester resin, Polystyrene resin.

  When the surface layer is a layer containing a thermoplastic resin as a main component, the content of the thermoplastic resin as a main component in the surface layer is not particularly limited, but is the total weight (100% by weight) of the surface layer. On the other hand, 50 weight% or more is preferable, More preferably, it is 70 weight% or more, More preferably, it is 90 weight% or more. Although the upper limit of the said content is not specifically limited, 100 weight% or less is preferable, More preferably, it is less than 100 weight%. If the content is less than 50% by weight, the shrinkage characteristics and thermal shrinkage of the label may be lowered.

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

(Base layer)
In the present specification, the “base layer portion” is a portion sandwiched between the surface layers in the shrink film of the present invention. Of the layers in the base layer part, all or some of the layers may be the same layer or different layers (layers having different resin compositions and layer thicknesses). Also good.

  The base layer portion includes 5 to 65 layers. The base layer portion has an interface formed by adjoining the layers. Further, three or more of the interfaces are interfaces (interface (L)) having a T-type peel strength lower than the T-type peel strength of the surface layer and the base layer portion. By providing the base layer portion, the shrink label of the present invention having the shrink film of the present invention can achieve both excellent drop resistance and tearability. In the present specification, among the interfaces formed by adjoining the layers in the base layer portion, an interface having a T-type peel strength lower than the T-type peel strength of the surface layer and the base layer portion, It may be referred to as “interface (L)”. The T-type peel strength can be measured by, for example, a T-type peel test in accordance with JIS K 6854-3. When a plurality of the same interfaces exist in the base layer portion, the T-type peel strength at all the same interfaces may be regarded as the same.

  In the base layer portion, the number of the interfaces (L) is 3 or more, preferably 4 or more, more preferably 5 or more, and still more preferably 8 or more. The upper limit of the interface (L) is not particularly limited as long as it is not more than the number of interfaces formed by adjacent layers in the base layer portion. Especially, it is especially preferable that all of the interfaces formed by adhering the layers in the base layer portion are interfaces (L). Since the interface (L) has relatively low T-type peel strength in the shrink film of the present invention, when the base layer portion has 3 or more of the interfaces (L), the tearability of the label is improved and the film is dropped. At this time, the stress due to the impact of the drop is dispersed and relaxed at each interface, and the drop resistance is also improved. In addition, since the base layer is multilayered, the label is delaminated even when the T-type peel strength at the interface where the layers in the base layer are adjacent to each other is relatively weak. Hateful.

  The T-type peel strength at the interface (L) is not particularly limited, but is preferably 0.1 to 1.5N, more preferably 0.1 to 1.0N, and still more preferably 0.2 to 0.8N. . When the T-type peel strength is 0.1 N or more (particularly 0.2 N or more), delamination in the base layer at room temperature can be suppressed, which is preferable. It is preferable that the T-type peel strength is 1.5 N or less (particularly 1.0 N or less) because the dispersibility of stress on the label is improved and the label drop resistance is more excellent. The T-type peel strength is measured with a measurement width of 15 mm.

  The T-type peel strength between the surface layer and the base layer portion is not particularly limited, but preferably exceeds 0.8N, more preferably exceeds 0.9N, and further preferably exceeds 1N. 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 exceeds 0.8 N, it is preferable because delamination between the surface layer and the base layer portion can be suppressed. It is preferable that the T-type peel strength is 10 N or less because it is possible to prevent excessive stress dispersion in the base layer portion and to suppress delamination in the base layer portion. The T-type peel strength is measured with a measurement width of 15 mm.

  The number of layers (number of layers) contained in the base layer portion is 5 to 65 layers, preferably 5 to 33 layers, and more preferably 9 to 33 layers. If the number of layers is less than 5, the effect of the base layer is not sufficient, and the effect of improving the label drop resistance cannot be obtained. In addition, the effect of improving the rigidity may not be obtained. On the other hand, when the number of layers exceeds 65 layers, the thickness of the base layer portion (thickness per layer) becomes too thin when the thickness (total thickness) of the shrink film is within a range suitable for shrink labels. As a result, the drop resistance of the shrink label is reduced. In addition, the rigidity may decrease.

  The layer in the said base layer part will not be specifically limited if it is a layer which can be laminated | stacked with the surface layer, each other layer in a base layer part, or both. The layer in the above base layer portion can cause the shrink label to exhibit heat shrinkability, optimize the shrinkage rate, and reduce the rigidity of the shrink label without impairing the adhesion between the base layer portion and the surface layer and the adhesion within the base layer portion. A layer for increasing the thickness is preferable.

  Although the layer in the said base layer part is not specifically limited, The layer which has a thermoplastic resin as a main component is preferable. The thermoplastic resin is not particularly limited, but is exemplified and explained as a thermoplastic resin that may be included in the surface layer, polyester-based resin, polystyrene-based resin, polyolefin-based resin, vinyl chloride-based resin, polycarbonate-based resin Examples thereof include resins, polyamide resins, and thermoplastic elastomers. As for the said thermoplastic resin, only 1 type may be used and 2 or more types may be used.

  When the resin layer as the layer in the base layer portion is a layer mainly composed of a thermoplastic resin, the content of the thermoplastic resin in the resin layer is not particularly limited, but the total weight of the resin layer (100 weight) %) Is preferably 50% by weight or more, more preferably 70% by weight or more, and still more preferably 90% by weight or more. Although the upper limit of the said content is not specifically limited, What is necessary is just 100 weight% or less. If the content is less than 50% by weight, the shrinkage characteristics and thermal shrinkage of the label may be lowered. In addition, content of the said thermoplastic resin is a total amount of content of all the thermoplastic resins contained in a resin layer.

  The resin layer as a layer in the base layer portion is a rosin resin, a hydrogenated rosin resin, a terpene resin, a terpene-phenol resin, a hydrogenated terpene resin, a coumarone within the range not impairing the effects of the present invention. It may contain a tackifier resin such as an aromatic resin, a hydrogenated coumarone resin, or a petroleum resin; an aromatic hydrocarbon resin; a phenol resin; an alicyclic hydrocarbon resin. Further, the resin layer is within the range not impairing the effects of the present invention, and includes lubricants, fillers, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, antifogging agents, flame retardants, colorants, pinning. You may contain additives, such as an agent (alkaline earth metal) and a softening agent. Moreover, the said resin layer may contain the collection | recovery raw material by which the film piece at the time of film manufacture was re-pelletized.

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

  The shrink film of the present invention is not particularly limited as long as three or more of the interfaces formed by adjacent layers in the base layer portion are interfaces (L). In order to obtain such a shrink film of the present invention, specifically, the T-type peel strength at the interface where the layers in the base layer portion are formed adjacent to each other is lowered, and the outermost layer and the surface layer of the base layer portion. What is necessary is just to make T-type peeling strength high. However, the lower limit of the T-type peel strength at the interface where the layers in the base layer portion are formed adjacent to each other needs to prevent delamination at room temperature when the film is subjected to stress.

  For example, a specific interface exists in the base layer part as a specific mode for preventing the T-type peel strength of the interface formed adjacent to each other in the base layer part from being low and preventing delamination. And the specific interface is defined as an interface (L). That is, the base layer portion is not particularly limited, but has at least two specific resin layers (the resin layer (A) and the resin layer (B)) as the layer, and the resin layer (A) and the resin layer (B ) Are adjacent (directly laminated), and three or more of the interfaces are preferably interfaces (L). In the present specification, the interface where the resin layer (A) and the resin layer (B) are formed adjacent to each other may be referred to as “interface [A / B]”.

  When the base layer portion has at least the resin layer (A) and the resin layer (B) as layers, it is not particularly limited, but it is preferable that three or more of the interfaces [A / B] are interfaces (L), more preferably. Is 4 or more, more preferably 5 or more, and particularly preferably 8 or more. The upper limit of the number of the interfaces (L) is 64, preferably 32. In particular, it is preferable that all the interfaces [A / B] are interfaces (L).

  When there are a plurality of resin layers (A) in the base layer part, all or some of the plurality of resin layers (A) may be the same layer or different layers ( The resin composition and layer thickness which comprise a layer may differ. Similarly, when there are a plurality of resin layers (B) in the base layer portion, all or some of the plurality of resin layers (B) may be the same layer, Different layers (layers having different resin compositions and layer thicknesses) may be used. The resin layer (A) and the resin layer (B) are different from each other, and are layers mainly composed of different types of resins. Although the said base layer part may contain layers (other layers) other than the resin layer (A) and the resin layer (B) as long as the effects of the present invention are not impaired, the resin layer (A) and the resin layer Most preferably, it is composed only of (B) and does not contain other layers. The other layers are included, for example, between the resin layer (A) and the resin layer (B), between the resin layers (A), between the resin layers (B), or as the outermost layer of the base layer portion. It may be.

  The combination of the resin as the main component of each of the resin layer (A) and the resin layer (B) is not particularly limited, but from the viewpoint of making the interface (L), polyester resin and polystyrene resin, polyester resin and polyolefin resin. Resin or polystyrene resin and polyolefin resin are preferred. The combination of the polyester resin and the polyolefin resin is preferably a polyester resin and a polyethylene resin, or a polyester resin and a polypropylene resin, and more preferably a polyester resin and a polyethylene resin. The combination of the polystyrene resin and the polyolefin resin is preferably a polystyrene resin and a polypropylene resin.

  In addition, when the combination of the resin having the main components of the resin layer (A) and the resin layer (B) is a polyester resin and a polystyrene resin layer, the surface layer is not particularly limited, but the polyester resin is the main component. It is preferable that the layer be Moreover, when the combination of the resin having the resin layer (A) and the resin layer (B) as the main components is a polystyrene resin and a polyolefin resin, the surface layer is not particularly limited, but the polystyrene layer is the main component. A layer is preferred. In this case, the polyolefin resin is preferably a polypropylene resin from the viewpoint of transparency.

  The resin layer (A) and the resin layer (B) are not particularly limited, but in addition to the main resin, polyester resin, polystyrene resin, polyolefin resin, vinyl chloride resin, polycarbonate resin, polyamide, respectively. A resin different from the main component, such as a resin or a thermoplastic elastomer, may be included. In the case where the resin layer (A) and / or the resin layer (B) contains a resin other than the resin as a main component, the resin layer is particularly preferable from the viewpoint of the T-type peel strength between the resin layer (A) and the resin layer (B). The resin other than the resin as the main component in (A) is preferably a resin as the main component of the resin layer (B), and the resin other than the resin as the main component in the resin layer (B) is a resin layer (A A resin having a main component of) is preferred. The content of the resin other than the main resin is not particularly limited, but is preferably 5 to 45% by weight, more preferably 10 to 40% by weight, and still more preferably 15 to 35% by weight with respect to the entire layer. .

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

  The combination of the resin layer (A) and the resin layer (B) is a combination of a layer mainly composed of a polyester resin and a layer mainly composed of a polystyrene resin. And a layer containing a polystyrene resin in an amount of 5 to 45% by weight of the whole layer and a layer containing a polystyrene resin in an amount of 90% by weight or more of the whole layer; A layer containing 5 to 45% by weight of the entire polyester resin and a layer containing 90% by weight or more of the whole polyester resin; containing 50% by weight or more of the polyester resin and A layer containing 5 to 45% by weight of the polystyrene-based resin, 50% by weight or more of the polystyrene-based resin of the whole layer, and 5% of the whole of the polyester-based resin. Combination of layers preferably contains 45 wt%. The surface layer in this case is not particularly limited, but the main component is a polystyrene resin or a polyester resin, and the content of the resin having the main component is relative to the total weight (100% by weight) of the surface layer. 90% by weight or more, more preferably 95% by weight or more.

  In the shrink film of the present invention, the T-type peel strength between the surface layer and the base layer is higher than the interface (L). In order to obtain such a shrink film of the present invention, it is preferable that the T-type peel strength between the surface layer and the base layer is higher. Specifically, the T-type peel strength between the outermost layer of the base layer and the surface layer is You can make it higher. As a specific aspect for that purpose, for example, the outermost layer and the surface layer of the base layer portion may be specified layers that increase the T-type peel strength.

  In the shrink film of the present invention, the combination of the outermost layer and the surface layer of the base layer is not particularly limited, but from the viewpoint of further increasing the T-type peel strength of the surface layer and the base layer, the same system resin is the main component. A combination of layers is preferred. The resin of the same type is not particularly limited, but a polyester resin and a polyester resin, a polystyrene resin and a polystyrene resin, a polyolefin resin and a polyolefin resin, and the like, more preferably a polyester resin and a polyester resin, Polystyrene resin and polystyrene resin.

  In the base layer portion, the resin layer (A) and the resin layer (B) are not particularly limited, but it is more preferable that the resin layer (A) and the resin layer (B) are alternately and directly laminated without interposing other layers. That is, the base layer part particularly preferably includes 5 to 65 layers of the resin layers (A) and the resin layers (B) alternately as a layer. In the present specification, as a layer, a base layer portion including a total of 5 to 65 layers of the resin layer (A) and the resin layer (B) may be referred to as a “base layer portion having a preferable configuration”. is there.

  In the base layer portion having the above preferable configuration, the laminated structure of the base layer portion is not particularly limited, but specifically, “resin layer (A) / resin layer (B)” is a repeating unit without interposing other layers. (Resin layer (A) / Resin layer (B) / Resin layer (A) / Resin layer (B) /.../ Resin layer (A) / Resin layer (B) / Resin layer (A )), (Resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) /.../ resin layer (B) / resin layer (A) / resin layer (B) ), (Resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) /.../ resin layer (A) / resin layer (B)) or (resin layer (B) ) / Resin layer (A) / resin layer (B) / resin layer (A) /... / Resin layer (B) / resin layer (A)). Further, the outermost layers on both surfaces of the base layer portion may be the resin layer (A) or the resin layer (B).

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

  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 drop resistance and rigidity of the label are further improved, which is preferable. When the thickness is 100 μm or less, the tearability of the label is more excellent and preferable.

  The thickness of the surface layer (the thickness of one layer) is not particularly limited, but is preferably 1 to 15 μm, more preferably 2 to 10 μm, and still more preferably 2.5 to 8 μm. When the thickness exceeds 15 μm, delamination may occur between the surface layer and the base layer portion. 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.

  Although the thickness of the said base layer part is not specifically limited, 8-90 micrometers is preferable, More preferably, it is 10-45 micrometers, More preferably, it is 11-40 micrometers. It is preferable for the thickness to be 90 μm or less because delamination is difficult even when the T-type peel strength at the interface between layers in the base layer portion is relatively low.

  The thickness of the layer in the base layer portion (the thickness of one layer) is not particularly limited, but is preferably 0.2 μm or more (for example, 0.2 to 10 μm), more preferably 0.3 μm or more (for example, 0.3). ~ 5 μm). In addition, as for the thickness of the some layer in a base layer part, all or one part of them may be the same, and may mutually differ. For example, the layer of the base layer portion in contact with the surface layer may be thinner than the layer in the base layer portion.

  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 is thicker than 2: 1, it is preferable because wrinkles and delamination between the surface layer and the base layer hardly occur. On the other hand, it is preferable that the surface layer is thicker than 1:10 because the rigidity and wear resistance of the label are further improved.

  In the base layer portion having the preferred configuration, the thickness of the resin layer (A) (the total thickness of all the resin layers (A)) and the thickness of the resin layer (B) (the total thickness of all the resin layers (B)) ) Ratio [(thickness of resin layer (A)) :( thickness of resin layer (B)]] is not particularly limited, but is preferably 10: 1 to 1:10, more preferably 8: 1 to 1: 8, more preferably 5: 1 to 1: 5.

  In the shrink film of the present invention, the delamination strength in the 180 ° direction at 90 ° C. at which the resin layer (A) and the resin layer (B) are formed adjacent to each other is not particularly limited, but is preferably 2N or more. Is 3N or more, more preferably 4N or more. The upper limit of the delamination strength in the 180 ° direction at 90 ° C. is not particularly limited, but is preferably 10N, more preferably 8N. When the delamination strength in the 180 ° direction at 90 ° C. is 2N or more, delamination can be hardly caused even during shrink processing. When a plurality of interfaces [A / B] are present in the shrink film of the present invention, the delamination strength in the 180 ° direction at 90 ° C. of all the interfaces [A / B] is 2N or more. When there are a plurality of the same interface [A / B] in the shrink film, the delamination strength in the 180 ° direction at 90 ° C. of the same interface [A / B] may be regarded as the same.

The delamination strength in the 180 ° direction at 90 ° C. of the interface [A / B] is not particularly limited. For example, according to JIS K 6854-2, the delamination strength in the 180 ° direction when heated to 90 ° C. Can be obtained by measuring. Specifically, it can be measured by the following method.
(Measurement method of delamination strength in the direction of 180 ° at 90 ° C. of interface [A / B])
The interface [A / B] is partially peeled from the end face in the main orientation direction of the shrink label (or shrink film), the peeled part (peeled part), and the part that is peeled off (the peeled part) Form. The said to-be-separated part is fixed to a glass plate using an adhesive tape. Then, it heats to 90 degreeC from the glass plate side. Then, the glass plate is fixed so as not to move, the measurement width is set to 15 mm, and the peeling portion is pulled in the 180 ° direction at a pulling speed of 200 mm / min. The strength at the time of pulling is measured, and the strength is defined as the delamination strength in the 180 ° direction at 90 ° C. of the interface [A / B]. Note that the thin side of the shrink label when peeled is the peeled portion, and the thick side is the peeled portion.

  In the shrink film of the present invention, the delamination strength in the 180 ° direction at normal temperature of the interface formed by adjoining the resin layer (A) and the resin layer (B) is not particularly limited, but is preferably less than 1N, more Preferably it is 0.9N or less, More preferably, it is 0.8N or less. The lower limit of the 180 ° direction delamination strength at normal temperature is not particularly limited, but is preferably more than 0N, more preferably 0.1N or more, and further preferably 0.2N or more. When the delamination strength in the 180 ° direction at room temperature is less than 1N, the delamination strength at the interface [A / B] is not too strong, the shrink film becomes soft, and the tearability of the label is improved. When there are a plurality of interfaces [A / B] in the shrink film of the present invention, the delamination strength in the 180 ° direction at normal temperature of all the interfaces [A / B] is more than 0N and less than 1N. When there are a plurality of the same interface [A / B] in the shrink film, the delamination strength in the 180 ° direction at the normal temperature of the same interface [A / B] may be regarded as the same.

The delamination strength in the 180 ° direction at normal temperature of the interface [A / B] is not particularly limited. For example, by measuring the delamination strength in the 180 ° direction at normal temperature in accordance with JIS K 6854-2. Can be obtained. Specifically, for example, it can be measured by the following method.
(Measurement method of delamination strength in the direction of 180 ° at the interface [A / B] at normal temperature)
The interface [A / B] is partially peeled from the end face in the main orientation direction of the shrink label (or shrink film), the peeled part (peeled part), and the part that is peeled off (the peeled part) Form. The said to-be-separated part is fixed to a glass plate using an adhesive tape. Then, in a normal temperature (23 ° C.) environment, the glass plate is fixed so as not to move, the measurement width is set to 15 mm, and the peeling portion is pulled in the 180 ° direction at a pulling speed of 200 mm / min. The strength at the time of pulling is measured, and the strength is defined as the delamination strength in the 180 ° direction at normal temperature of the interface [A / B]. Note that the thin side of the shrink label when peeled is the peeled portion, and the thick side is the peeled portion.

  The 180 ° direction delamination strength at 90 ° C. and the 180 ° direction delamination strength at 90 ° C. include, for example, the raw material composition, the physical properties of the resin layer (A) and the resin layer (B), and the film production conditions. (For example, extrusion temperature, stretching temperature, stretching ratio, etc.) can be adjusted.

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

  The shrinkage stress at 90 ° C. of the shrink film of the present invention is preferably smaller than the delamination strength in the 180 ° direction at 90 ° C. of the interface [A / B]. This is preferable because delamination can hardly occur even during shrink processing regardless of the level of delamination strength in the 180 ° direction at room temperature. When there are a plurality of interfaces [A / B] in the base layer, the shrinkage stress at 90 ° C. of the shrink film of the present invention is the delamination strength in the direction of 180 ° at 90 ° C. of all the interfaces [A / B]. Is preferably smaller.

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

  The shrink film of the present invention is preferably a film oriented in at least a uniaxial direction (for example, a film oriented uniaxially, biaxially or multiaxially) from the viewpoint of exhibiting shrink characteristics. Furthermore, it is preferable that all the film layers (each layer of the base layer portion including the surface layer, the resin layer (A), and the resin layer (B)) are at least uniaxially oriented. As the shrink film, in particular, a uniaxially oriented film (uniaxially oriented film) or a biaxially oriented film (biaxially oriented film) is often used. A film (substantially uniaxially stretched film) is generally used. In particular, a film uniaxially oriented in the width direction is preferable.

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

  The shrinkage rate of the shrink film of the present invention (before shrink processing) in the main orientation direction at 90 ° C. for 10 seconds (warm water treatment) (sometimes referred to as “thermal shrinkage rate (90 ° C., 10 seconds)”). Although not particularly limited, 45% or more (for example, 45 to 80%) is preferable. When the thermal shrinkage rate (90 ° C., 10 seconds) is less than 45%, in the shrink processing step in which the shrink label is closely adhered to the container by heat, the shrinkage is not sufficient, and it becomes difficult to follow the shape of the container. The finish may be poor for shaped containers.

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

  When the shrink film of the present invention is transparent, the haze value [based on JIS K 7136, converted to a thickness of 40 μm, unit:%] of the shrink film is not particularly limited, but is preferably 10% or less. Preferably it is 7% or less, More preferably, it is 5% or less. When the haze value exceeds 10%, the inside of the shrink film (the side that becomes the container side when the shrink label is attached to the container) is printed, and the shrink label that shows the print through the shrink film (back printed shrink label) When used as a product, the printing may become cloudy and the decorativeness may deteriorate. However, even if the haze value exceeds 10%, it may be opaque in applications other than the above-described applications (print printed shrink labels) that show printing through a shrink film, and can be used sufficiently.

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

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

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

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

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

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

  1 to 3 are schematic views (partial cross-sectional views) each showing an example of the shrink label of the present invention, in particular, a shrink label having a shrink film including the base layer portion having the above-mentioned preferred configuration. 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 an outermost layer (a layer in contact with the surface layer 11) as the resin layer (A) 12a, and the resin layers (A) 12a and the resin layers (B) 12b are alternately laminated in a total of nine layers. Is formed. The surface layer 11 and the base layer portion 12 are directly laminated without interposing other layers. Specifically, the surface layer 11 and the resin layer (A) 12a that is the outermost layer of the base layer portion 12 are directly laminated without interposing another layer.

  The shrink label 3 of the present invention shown in FIG. 2 includes the shrink film 1 of the present invention and a printing layer 2 provided on one side of the shrink film 1 of the present invention. The shrink film 1 of the present invention includes a base layer portion 12 and a surface layer 11 provided on each side of the base layer portion 12. In the shrink label 3 of the present invention shown in FIG. 2, the base layer portion 12 is a shrink label in which the positional relationship between the resin layer (A) 12a and the resin layer (B) 12b is reversed with respect to FIG. . That is, the base layer portion 12 has the outermost layer (the layer in contact with the surface layer 11) as the resin layer (B) 12b, and the resin layer (A) 12a and the resin layer (B) 12b are alternately laminated in a total of nine layers. Has been formed. The surface layer 11 and the base layer portion 12 are directly laminated without interposing other layers. Specifically, the surface layer 11 and the resin layer (B) 12b that is the outermost layer of the base layer portion 12 are directly laminated without interposing another layer.

  The shrink label 3 of the present invention shown in FIG. 3 includes the shrink film 1 of the present invention and a printed layer 2 provided on one side thereof. The shrink film 1 of the present invention includes a surface layer 11 and a base layer portion 12. The outermost layer (the layer in contact with the surface layer 11) is the resin layer (A) 12a, and the resin layer (A) 12a and the resin layer (B) 12b are alternately arranged in a total of 17 It is formed by layering. Also in FIG. 3, the surface layer 11 and the base layer portion 12 are directly laminated without interposing other layers, and the surface layer 11 and the resin layer (A) 12 a that is the outermost layer of the base layer portion 12 are the other layers. It is laminated directly without going through. In the shrink label 3 of the present invention shown in FIG. 3, the resin layer (A) 12a and the resin layer (B) 12b may be in the opposite positional relationship.

  Although the thickness (total thickness) of the shrink label of this invention is not specifically limited, 10-110 micrometers is preferable, More preferably, it is 15-60 micrometers, More preferably, it is 20-50 micrometers. When the thickness is 10 μm or more, the drop resistance and rigidity of the label become higher, which is preferable. When the thickness is 110 μm or less, the tearability of the label is more excellent and preferable.

  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 film of the present invention is particularly preferably used for a cylindrical shrink label from the viewpoint of excellent label drop resistance and tearability. That is, the shrink label of the present invention is preferably a cylindrical shrink label.

  The cylindrical shrink label has a background print layer, a design print layer, and a shrink label having the shrink film of the present invention in this order in a cylindrical shape so that the background print layer is inside, and both ends (both ends of the shrink label). ) Is preferably a cylindrical shrink label (hereinafter sometimes referred to as “cylindrical shrink label of the present invention”). In the cylindrical shrink label of the present invention, the shrink film of the present invention is oriented at least in the circumferential direction of the cylindrical shrink label (formed in a cylindrical shape so that the main orientation direction of the shrink film of the present invention is the circumferential direction). Preferably). Moreover, it is preferable that the said seal part is joined with the solvent or the adhesive agent. Moreover, it is preferable that the shrink film of this invention is joined to the cylindrical shrink label of this invention with the solvent or the adhesive agent in the said seal part from the adhesive viewpoint of a seal part. In order that the shrink films of the present invention are bonded to each other at the seal portion, the background printing layer is formed on a portion (one end portion of the shrink label) of the seal portion bonded with the solvent or the adhesive. And it is preferable not to have the said design printing layer. In particular, it is preferable to have a seal portion in which the shrink films of the present invention are bonded to each other with a solvent in a portion not having the background print layer and the design print layer. In addition, since the part which is not joined among the said both ends does not have influence on adhesiveness even if it has a printing layer etc., it may have the said background printing layer and the said design printing layer.

  4 and 5 are schematic views showing an example of a cylindrical shrink label which is an embodiment of the shrink label of the present invention. The cylindrical shrink label 4 of the present invention shown in FIG. 4 is formed into a cylindrical shape by superimposing the other end on the outside of one end of the shrink label of the present invention formed in a rectangular shape. A seal portion 41 is formed by joining the outer surface of the portion 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 orientation direction.

  FIG. 5 is an enlarged view of the cross section of A-A ′ in FIG. 4 near the seal portion. In the seal portion 41, both ends of the shrink label are joined with a solvent or an adhesive 53. Specifically, the shrink label 3 of the present invention has a design printing layer 52 except for an area having a predetermined width from the other end of one surface (surface on the cylindrical inner surface side) of the shrink film 1 of the present invention. The background print layer 51 is laminated in this order. In a region having a predetermined width from the other end of the shrink label 3 of the present invention, the background print layer 51 and the design print layer 52 are not formed, the shrink film 1 of the present invention is exposed, and a film exposed surface is formed. The seal portion 41 is formed by joining a film exposed surface formed on the inner surface side of the other end portion of the shrink label 3 of the present invention and an outer surface (film exposed surface) of one end portion with a solvent or an adhesive 53. Yes. That is, in the seal part 41, it is preferable that the shrink films 1 of the present invention are joined together with a solvent or an adhesive 53. In addition, even if it has a printing layer, such as a background printing layer and a design printing layer, the part which is not joined among the said both ends has an influence on adhesiveness, Therefore It may have a printing layer.

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

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

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

  The shrink film of the present invention has a base layer portion containing 5 to 65 layers and a surface layer provided on both sides of the base layer portion, and the base layer portion has an interface formed by adjoining the above layers. And the T-type peel strength of three or more of the interfaces is an interface (interface (L)) lower than the T-type peel strength of the surface layer and the base layer portion. Thereby, the shrink label of the present invention has high strength, suppresses the breakage of the label due to the impact when the labeled container is dropped, and makes it possible to consciously easily tear the label in the vertical direction. . This is because the stress that tears the label caused by the impact when the container with the label is dropped is transferred / dispersed to the stress that peels the multiple interfaces (L) in the base layer with lower T-type peel strength. It is presumed that the stress is prevented from being concentrated in one place. Note that as the number of the interfaces (L) is larger, the stress that tears the label is more dispersed, so that the strength of the label becomes higher and the resistance to dropping can be compensated. Further, the impact at the time of dropping does not concentrate on the stress at which the label is torn, but when the label is intentionally torn in the longitudinal direction, the stress is concentrated on the tearing portion, so that the label can be easily torn.

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

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

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

  Although the said film preparation process is not specifically limited, In the case of the shrink film in which a base layer part is formed only from a resin layer (A) and a resin layer (B), the raw material ("Raw material (a) which comprises a resin layer (A)" ), A raw material constituting the resin layer (B) (sometimes referred to as “raw material (b)”), and a raw material constituting the surface layer (when referred to as “raw material (c)”) And a raw material (a) and a raw material (b), which are melted (or melt-kneaded) in the first stage, are laminated, and further multilayered A second step of forming a layered product by forming a layered product; and the raw material (c) melted in the first step is laminated one layer at a time on both sides of the layered product formed in the second step. It is preferable to include at least a third 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.

  The melt kneading is not particularly limited, but the raw material (a), the raw material (b), and the raw material (c) can be kneaded using a kneading apparatus after melting (or simultaneously with melting). By kneading each raw material, in the plastic film of the present invention, the T-type peel strength between the layers of the surface layer and the base layer can be adjusted to a desired strength.

  The kneading apparatus can be performed using a known or conventional kneading apparatus and is not particularly limited, and examples thereof include a static mixer, a tank mixer, a homomixer, and a homodisper.

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

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

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

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

  In the third stage, the laminate (for example, the laminate 2, 4, or 6) formed in the second stage was melted (or melt-kneaded) in the first stage, When laminating the raw material (c), 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. A multilayer structure in which the raw material (c) melted (or melt-kneaded) in the first stage is laminated on both sides of the laminate formed in the second stage by the third stage. Is obtained.

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

  [Raw material (a) / Raw material (b) / Raw material (a) / Raw material (a) / Raw material (b) / Raw material (a) /.../ Raw material (a) / Raw material (b) / Raw material ( a)] has the structure [resin layer (A) / resin layer (B) / resin layer (A) / resin layer (A) / resin layer (B) / resin layer (A) / .. ./Resin layer (A) / resin layer (B) / resin layer (A)] should be the base layer portion, but in reality, the same material of the laminate 2 was laminated [raw material ( The portion of [resin layer (A) / resin layer (A)] formed from a) / raw material (a)] becomes one resin layer (A) because the interface is not visible, and [resin layer (A) / The base layer portion has a structure of resin layer (B) / resin layer (A) / resin layer (B) /... / Resin layer (A) / resin layer (B) / resin layer (A)]. Similarly, the portion of [resin layer (B) / resin layer (B)] formed from [raw material (b) / raw material (b)] obtained by laminating the same material of the above-described laminate 4 becomes invisible. Since it becomes a resin layer (B), the base layer portion derived from the laminate 4 is [resin layer (B) / resin layer (A) / resin layer (B) / resin layer (B) / resin layer (A). / Resin layer (B) /... / Resin layer (B) / resin layer (A) / resin layer (B)] should be the base layer, but in reality, [resin layer (B ) / Resin layer (A) / resin layer (B) / resin layer (A) /... / Resin layer (B) / resin layer (A) / resin layer (B)] Become.

  Although it does not specifically limit as said other step, The step of extending | stretching, the step of performing surface treatment, etc. are mentioned. For example, the laminated unstretched film produced in the third stage further has a stage of stretching. In addition, when the surface layer and the outermost layer of the base layer portion are layers made of the same resin composition, the interface is not visible, and the surface layer and the outermost layer of the base layer portion are one layer ( Surface layer).

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

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

  In the above film production process, the example in which the base layer portion is formed only from the resin layer (A) and the resin layer (B) has been described, but also when including a layer other than the resin layer (A) and the resin layer (B), The base layer portion and the laminated unstretched film can be produced by the same process. Moreover, although the said film preparation process showed the example which melt | dissolves and uses three types of raw materials (or melt-kneading), it is not limited to this, Two types of raw materials (for example, raw material (a) and raw material) (B)) is melted (or melt-kneaded), and two kinds of raw materials (for example, raw material (a) and raw material (b)) melted (or melt-kneaded) in the first stage are adjacent to each other. In this case, the third stage is not provided, and the outermost layer of the second stage laminate is the surface layer.

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

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

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

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

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

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

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

  The labeled container can be produced, for example, by externally fitting a cylindrical shrink label to a predetermined container, and then thermally shrinking the cylindrical shrink label by heat treatment so as to follow and closely adhere to the container (shrink processing). Examples of the heat treatment method include a method of passing through a hot air tunnel or a steam tunnel, a method of heating with radiant heat such as infrared rays, and the like. In particular, a method of treating with steam at 80 to 100 ° C. (passing through a heating tunnel filled with steam and steam) is preferable. Moreover, 101-140 degreeC dry steam can also be used. Although the said heat processing is not specifically limited, It is preferable to implement in the temperature range from which the temperature of a shrink film will be 85-100 degreeC (especially 90-97 degreeC). Since the shrink film of the present invention can be heat-treated at a particularly high temperature, it can be used for containers that require high shrinkage. 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 material for the surface layer (raw material (c)), the raw material for the resin layer (A) (raw material (a)), the raw material for the resin layer (B) used in the examples and comparative examples (raw material ( The composition of b)), the structure and evaluation results of the shrink film and the shrink label produced in Examples and Comparative Examples are shown.

Example 1
(material)
As a raw material constituting the resin layer (A) (raw material for the resin layer (A)), a polystyrene resin A (manufactured by Stylus Lucon Co., Ltd., trade name “Styrolux S”, content of structural unit derived from butadiene: 12 weight 14.7% by weight, polystyrene resin B (manufactured by Stylorusion, trade name “Styrolox T”, content of structural unit derived from butadiene: 26% by weight), 34.3% by weight, polyester resin A (manufactured by Eastman Chemical, trade name “EMBRACE 21214”) was 51% by weight, and melt blended.
As a raw material constituting the resin layer (B) (raw material for the resin layer (B)), the polystyrene resin A was 30% by weight and the polystyrene resin B was 70% by weight, and melt blended.
100% by weight of polyester-based resin A was used as a raw material (surface layer raw material) constituting the surface layer.

(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 220 ° C. Was introduced. Using the above three extruders, melt-kneading and extrusion were performed. Using a laminating apparatus in which the melt-kneaded raw material for the resin layer (A) and the raw material for the resin layer (B) are combined with a feed block of a two-kind / three-layer type and a four-part multiplier, the resin layer ( A) Raw material / Resin layer (B) Raw material / Resin layer (A) Raw material 2 type 3 layer structure is divided, merged and laminated as one repeating unit to obtain a laminate (I) (the above 2 type 3 layer) 4 layers (repetition number 4)), and the melted and kneaded surface layer raw material is merged and laminated on both sides of the laminate (I) using a feed block, and the laminate (II ). Furthermore, after extruding the laminate (II) from a T-die, the laminate (II) was rapidly cooled on a casting drum cooled to 25 ° C. to obtain a laminated unstretched film in which surface layers were respectively provided on both sides of the base layer portion. .
Next, the laminated unstretched film is stretched 5 times at 85 ° C. in the width direction to be stretched mainly in the width direction, and a stretched film (shrink film) having heat shrinkability in that direction. Got.
The shrink film is [surface layer / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A). / Resin layer (B) / resin layer (A) / surface layer]. In the above-mentioned shrink film, the base layer part is 12 layers because the repeating unit of 2 types and 3 layers structure is laminated with a repetition number of 4, but the part where the raw materials for the resin layer (A) overlap is actually the interlayer The interface becomes invisible and overlaps into one layer. For this reason, the base layer portion is [resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) / Resin layer (B) / resin layer (A)], and the outermost layer of the base layer portion is the resin layer (A).

(Cylinder shrink label)
A part to be used as a seal part after forming a design print layer on one side of the shrink film using a process color printing ink while conveying the long body of the shrink film obtained above in the longitudinal direction by a gravure printing machine The printing layer having a thickness of about 3 μm was formed by forming a background printing layer using a white printing ink, and a long shrink label was obtained.
Subsequently, the long body of the shrink label is slit to have a predetermined width, and a plurality of cut portions and non-cut portions (length of the cut portion: 0. 0) are respectively provided at one end portion and the other end portion of the shrink label. 5 mm, the length of the non-cut parts: 3.5 mm) and provided alternately, after forming a perforation extending in the longitudinal direction (contracting direction and Cartesian directions), one end such that the width direction becomes circumferential portion And the other end are overlapped to form a cylinder, and the shrink film surfaces of the one end and the other end are sealed with a solvent to obtain a tubular long body of a shrink label. Furthermore, the cylindrical long body (label continuous body) of the shrink label was cut into individual label sizes to obtain a cylindrical shrink label.

(Container with label)
Next, the cylindrical shrink label is externally fitted to a container (Toyo Seikan Co., Ltd., 500 ml round PET container, weight 23 g), and then passed through a 90 ° C. steam tunnel to heat the tubular shrink label. Shrinked to obtain a labeled container.

Examples 2 to 4, Comparative Examples 1 and 2
As shown in Table 1, the composition and component ratio of the raw material (a), the raw material (b), and the raw material (c) are changed, and in the same manner as in Example 1, a shrink film, a cylindrical shrink label, and a label are attached. A container was obtained. Of the raw material (a), the raw material (b), and the raw material (c), a raw material using a mixed resin was obtained by melt blending a plurality of resins.

  In Examples 2 to 4 and Comparative Examples 1 and 2, the base layer portion in the shrink film has 12 layers because the repeating unit of 2 types, 3 layers is laminated with a repetition number of 4, but in reality, In the portion where the raw materials for the resin layer (A) overlap, the interface between the layers becomes invisible and overlaps to form one layer. Therefore, the shrink film is [surface layer / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer. (A) / resin layer (B) / resin layer (A) / surface layer]. Therefore, in the shrink film, the base layer portion is [resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer ( A) / resin layer (B) / resin layer (A)], and the outermost layer of the base layer portion is the resin layer (A).

Example 5
(material)
As a raw material for the resin layer (A), polystyrene resin C (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Clearen”) is 66% by weight, and polypropylene resin A (manufactured by ExxonMobil Chemical Co., trade name “Vistamaxx 3020FL”). ) Was 34% by weight and used after melt blending.
As a raw material for the resin layer (B), 100% by weight of polypropylene resin A was used.
As a raw material for the surface layer, 100% by weight of polystyrene resin C 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 220 ° C. Was introduced. Using the above three extruders, melt-kneading and extrusion were performed. The resin layer (A) and the raw material for the resin layer (B), which are melt-kneaded, are combined using a laminating apparatus in which a merging method is a combination of a two-type / three-layer type feed block and an 8-split multiplier. A) Raw material / Resin layer (B) Raw material / Resin layer (A) Raw material 2 type 3 layer structure is divided, merged and laminated as one repeating unit to obtain a laminate (III) (the 2 type 3 layer) The raw material for the surface layer that was melted and kneaded was merged and laminated on both sides of the laminate (III) using a feed block, and the laminate (IV ). Furthermore, after extruding the laminate (IV) from a T-die, it was rapidly cooled on a casting drum cooled to 25 ° C. to obtain a laminated unstretched film in which surface layers were provided on both sides of the base layer portion, respectively. .
Next, the laminated unstretched film is stretched 5 times at 85 ° C. in the width direction to be stretched mainly in the width direction, and a stretched film (shrink film) having heat shrinkability in that direction. Got.
The shrink film is [surface layer / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A). / Resin layer (B) / Resin layer (A) / Resin layer (B) / Resin layer (A) / Resin layer (B) / Resin layer (A) / Resin layer (B) / Resin layer (A) / Resin Layer (B) / resin layer (A) / surface layer]. In the above-mentioned shrink film, the base layer part is 24 layers because the repeating unit of 2 types, 3 layers structure is laminated with a repetition number of 8, but the part where the raw materials for the resin layer (A) overlap is actually the interlayer The interface becomes invisible and overlaps into one layer. For this reason, the base layer portion is [resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) / Resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A) / resin layer (B) / resin layer (A)], and the outermost layer of the base layer portion is the resin layer (A).

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

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

(1) T-type peel strength (T-type peel test)
For the shrink labels (before shrink processing) obtained in the examples and comparative examples, the interface [A / B] in the base layer part and the T-type peel strength between the surface layer and the base layer part were measured by the following method. .
From the shrink label, a rectangular sample with a width of 15 mm in the longitudinal direction of the shrink label (shrink film forming direction) and a length of 200 mm in the width direction of the shrink label (direction perpendicular to the longitudinal direction) Label width direction) × width 15 mm (longitudinal direction of shrink label)]. Hereinafter, the long side direction of the sample refers to the width direction of the shrink label, and the width direction of the sample refers to the longitudinal direction of the shrink label.
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 (If it broke, it was interrupted and data up to that point was obtained.)
First half deletion range: 50mm
Sensitivity: 1
In addition, when it was not able to peel, it was set as "it cannot peel" and shows that it is stronger than the T-type peel strength which could be measured.

(2) Label drop resistance The containers with labels obtained in the examples and comparative examples were allowed to stand for one day after being produced, and then dropped onto a concrete surface so that the bottom of the container hits from a height of 600 mm. This was repeated five times per container, and the presence or absence of label tearing was visually confirmed. The label drop resistance was evaluated according to the following criteria.
Good label drop resistance (○): No label tearing was confirmed. Label drop resistance was poor (x): Label tearing confirmed.

(3) labeled container obtained in tear Examples and Comparative Examples of the label along the label perforation, tore in the direction of contracting direction and Cartesian. And the tearability of the label was confirmed and evaluated according to the following criteria.
Good tearability (○): Easy tearability Available tearability level (×): Hard to tear

  As can be seen from Table 1, the shrink labels (Examples 1 to 5) of the present invention were excellent in the drop resistance and tearability of the label. On the other hand, among the interfaces between the resin layer (A) and the resin layer (B), a shrink label that does not have three or more interfaces having a T-type peel strength lower than the T-type peel strength between the surface layer and the base layer portion (comparative example) 1 and 2) had relatively poor label tearability.

DESCRIPTION OF SYMBOLS 1 Shrink film of this invention 11 Surface layer 12 Base layer part 12a Resin layer (A)
12b Resin layer (B)
2 Print Layer 3 Shrink Label of the Present Invention 4 Cylindrical Shrink Label of the Present Invention 41 Seal Part D Circumferential Direction 51 Background Print Layer 52 Design Print Layer 53 Solvent or Adhesive

Claims (4)

A shrink label having a shrink film,
The shrink film has a base layer portion including 5 to 65 layers, and a surface layer provided on both sides of the base layer portion,
The base layer portion has an interface formed by adjoining the layers;
The shrink label, wherein three or more of the interfaces are interfaces (interface (L)) having a T-type peel strength lower than the T-type peel strength of the surface layer and the base layer portion. The base layer portion has at least a resin layer (A) and a resin layer (B) as the layer,
A combination of resins as main components of the resin layer (A) and the resin layer (B),
Polyester resin and polystyrene resin, polyester resin and polyolefin resin, or polystyrene resin and polyolefin resin,
The resin layer (A) and the resin layer (B) have an interface (interface [A / B]) formed adjacent to each other,
The shrink label according to claim 1, wherein three or more of the interfaces [A / B] are the interfaces (L). The shrink label according to claim 1 or 2 , wherein a combination of the outermost layer of the base layer portion and the surface layer is a combination of layers mainly composed of the same resin. The shrink label according to any one of claims 1 to 3 , wherein a thickness (a thickness of one layer) of the layer in the base layer portion is 0.2 to 10 µm.

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