JP2015047758A - Shrink label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide shrink label which, even when thinned, has a shrink film excellent in solvent resistance and has excellent shrinkage properties.SOLUTION: A shrink label has a printing layer on at least one surface of a shrink film. The total thickness of the shrink film is 15-35 μm. The shrink film includes a base layer part and surface layers arranged on both sides of the base layer part and containing a polyester resin in an amount of 50 wt.% or more. The base layer part includes at least one central layer containing a polyester resin in an amount of 50 wt.% or more. The total thickness of the surface layers is 40% or more with respect to the total thickness of the shrink film. The printing layer is a solvent drying type printing layer.

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 film, for example, a shrink label including 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 (for example, 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.

JP 2002-351332 A

  In recent years, from the viewpoints of cost reduction and resource saving, shrink labels have been required to be thin (thinned). As a method for thinning the shrink label, a method for thinning the shrink film is generally used. However, when the shrink film having the laminated structure as described above is thinned, the shrink resistance of the shrink film decreases, and printing is performed when a printing ink containing a solvent as a dispersion medium is applied to provide a printing layer. When a relatively strong tension is applied to the shrink label such as when printing, making a shrink label bag, or mounting the label on a bottle using a labeler, the shrink label breaks. It was easy for a bug to occur. For this reason, even though it is thinner, it has the advantage of polystyrene resin, which is excellent in shrinking properties such as suppressing shrink wrinkles and bending of the edge caused by rapid shrinkage at the time of heat shrinkage. At present, there is a demand for shrink labels having excellent shrink films.

  That is, an object of the present invention is to provide a shrink label having a shrink film excellent in solvent resistance and excellent in shrinkage characteristics even if it is thinned.

  As a result of intensive studies to achieve the above object, the present inventors have found that a shrink film having a specific range of thickness and a shrink label having a solvent-dried printing layer, wherein the shrink film is a polystyrene resin. Having a surface layer mainly composed of a polyester-based resin on both sides of a base layer portion having at least one center layer mainly composed of a resin, and the total thickness of the surface layer is specified relative to the total thickness of the shrink film It has been found that a shrink label having a shrink film having excellent solvent resistance and excellent shrinkage characteristics can be obtained even when the thickness is reduced, and the present invention has been completed.

  That is, the present invention is a shrink label having a printed layer on at least one surface of the shrink film, wherein the shrink film has a total thickness of 15 to 35 μm, and the shrink film includes a base layer portion and a base layer portion. On both sides, it has a surface layer containing 50% by weight or more of a polyester resin, and the base layer part has at least one central layer containing 50% by weight or more of a polystyrene resin, A thickness is 40% or more with respect to the total thickness of the shrink film, and the print layer is a solvent dry type print layer.

  Furthermore, the present invention provides the shrink label, wherein the solvent-dried printing layer contains an ester and / or alcohol as a residual solvent.

  Furthermore, this invention provides the said shrink label whose total thickness of the said center layer is 20% or more with respect to the total thickness of the said shrink film.

  Furthermore, the present invention provides the shrink label, wherein the base layer portion has the center layer and an intermediate layer.

  Furthermore, the present invention provides the shrink label, wherein the base layer part includes the central layer and the intermediate layer alternately in a total of 5 to 65 layers.

  Moreover, this invention is a manufacturing method of the shrink label which has a printing layer in at least one shrink film, Comprising: The total thickness of the said shrink film is 15-35 micrometers, The said shrink film has a base layer part and a base layer part. On both sides, it has a surface layer containing 50% by weight or more of a polyester resin, and the base layer part has at least one central layer containing 50% by weight or more of a polystyrene resin, A step of preparing a shrink film having a thickness of 40% or more with respect to the total thickness of the shrink film, and a step of applying a solvent-drying type ink to the shrink film and drying and solidifying to form a printed layer. A shrink label manufacturing method is provided.

  Furthermore, the present invention provides the shrink label manufacturing method, wherein the solvent-drying ink contains an ester and / or an alcohol as a solvent, and the total content of the ester and the alcohol is 80% by weight or more based on the total solvent. I will provide a.

  The shrink label of the present invention has the above-mentioned specific configuration, so that it has a shrink film that has excellent shrinkage characteristics and excellent solvent resistance even when it is thinned. While having the advantage of the polystyrene resin that suppresses the wrinkles and the bending of the end, it is possible to suppress the disadvantage that the shrink label is broken when a relatively strong tension is applied to the shrink label.

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 solvent-dried printing layer on at least one surface of 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 the present invention may contain layers other than the shrink film of the present invention and the solvent-dried printing layer as long as the effects of the present invention are not impaired.

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

(Surface layer)
The surface layer (that is, the surface layer provided on each side of the base layer portion) in the shrink film of the present invention is a layer containing 50% by weight or more of polyester resin in the layer. By having the said surface layer, the shrink film of this invention is excellent in solvent resistance. Moreover, the shrinkage | contraction rate of the shrink label of this invention improves. Further, the rigidity is improved and the waist can be strengthened.

  The surface layer contains a polyester resin as an essential component. As for the said polyester-type resin, only 1 type may be used and 2 or more types may be used.

  Examples of the polyester resin include, for example, various polyesters having a dicarboxylic acid component and a diol component as essential components (that is, at least a structural unit derived from a dicarboxylic acid (structural unit) and a structural unit derived from a diol). As the main ones, a polymer, a copolymer, or a mixture thereof obtained by a condensation reaction of a dicarboxylic acid and a diol can be given.

  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, from the viewpoint of surface gloss, mechanical strength, and heat resistance, the polyester resin is preferably an aromatic polyester resin. The aromatic polyester-based resin means that 50 mol% or more (preferably 70 mol% or more) of the total dicarboxylic acid component is 50 mol% or more (preferably 70 mol% or more of the total diol component). Is a polyester resin whose aromatic diol is 70 mol% or more. Furthermore, the aromatic polyester-type resin which is a polymer by the condensation reaction of the dicarboxylic acid containing aromatic dicarboxylic acid and the diol containing aliphatic diol, or a mixture thereof is preferable.

  The aromatic polyester-based resin is not composed of a single repeating unit from the viewpoint of increasing the heat shrinkage rate and making it difficult to cause delamination between the surface layer and the base layer portion. A modified aromatic polyester resin containing a copolymerization component) 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.

  Specifically, as the polyester resin, from the viewpoint of shrinkage characteristics, polyethylene terephthalate (PET) using terephthalic acid as the dicarboxylic acid component and ethylene glycol (EG) as the diol component; terephthalic acid as the dicarboxylic acid component A modified aromatic polyester resin using ethylene glycol as a diol component and 1,4-cyclohexanedimethanol (CHDM) as a copolymer component (sometimes referred to as “CHDM copolymerized PET”); Modified aromatic polyester resin (“2,2-dialkyl-” using terephthalic acid as the acid component, ethylene glycol as the diol component, and 2,2-dialkyl-1,3-propanediol as the copolymer component 1,3-propanediol copolymerization Sometimes referred to as ET ") is preferable. 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 1,4-cyclohexanedimethanol copolymerized polyethylene terephthalate (CHDM copolymerized PET) and / or 2,2-dialkyl-1,3-propanediol copolymerized polyethylene terephthalate (2 , 2-dialkyl-1,3-propanediol copolymerized PET), more preferably CHDM copolymerized PET and / or neopentyl glycol copolymerized polyethylene terephthalate (NPG 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 preferably 10 mol% or more (for example, 10 to 40 mol%) from the viewpoint of optimizing the thermal deformation behavior of the surface layer and reducing delamination. Among them, for example, in the case of CHDM copolymerized PET, the CHDM ratio is preferably 12 to 30 mol% (EG is 70 to 88 mol%) in all diol components. 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 15-40 mol% (EG is 60-85 mol%) is preferable in a diol component. Further, a part of the EG component (preferably 1 to 10 mol% in the total diol component) may be replaced with diethylene glycol.

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

  The degree of crystallinity of the polyester resin measured by a differential scanning calorimetry (DSC) method (measured at a heating rate of 10 ° C./min) is preferably 15% or less, more preferably 10% or less. Further, the polyester-based resin is most preferably one having almost no melting point (melting peak) when measured by the DSC method (that is, a crystallinity of 0%). The crystallinity can be calculated from 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 same applies to the crystallinity of the polyester resin in the center layer and the polyester resin in the intermediate layer.

  The weight average molecular weight (Mw) of the polyester resin is preferably 15,000 to 100,000, more preferably 30,000 to 90,000, from the viewpoint of melting behavior and shrinkage behavior. In the case of 2,2-dialkyl-1,3-propanediol copolymerized PET, 50,000 to 70,000 is more preferable.

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

  In the present specification, the glass transition temperature (Tg) of the resin can be measured by DSC (differential scanning calorimetry) in accordance with, for example, JIS K7121. The DSC measurement is not particularly limited. For example, the DSC measurement can be performed using a differential scanning calorimeter “DSC6200” manufactured by Seiko Instruments Inc. under a temperature rising rate of 10 ° C./min.

  Commercially available products may be used as the polyester resin. For example, “EMBRACE 21214”, “EMBRACE LV” (CHDM copolymerized PET) manufactured by Eastman Chemical (Eastman Chemical), Bell Polyester Products, Inc. “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 content of the polyester-based resin in the surface layer is 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more based on the total weight (100% by weight) of the surface layer. is there. 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 said content is less than 50 weight%, the solvent resistance of a shrink film will fall. Furthermore, the thermal contraction rate and the rigidity of the label may decrease. The content of the polyester resin is the total content of all the polyester resins contained in the surface layer.

  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)
The base layer part in the shrink film of the present invention has at least one central layer mainly composed of polystyrene resin. The base layer portion may be a single layer including only the central layer, or may be a multilayer including one or more central layers. The base layer portion is not particularly limited, but may have a layer other than the center layer, such as an intermediate layer such as a layer that improves the adhesion between the surface layer and the center layer.

  In the present specification, the “base layer portion” means a portion sandwiched between the surface layers in the shrink film of the present invention. When there are a plurality of center layers in the shrink film of the present invention, all or some of the plurality of center layers may be the same layer, or the range of the center layer defined in the present application. The layers may be different from each other (layers having different resin compositions and layer thicknesses). Similarly, when there are a plurality of intermediate layers in the shrink film of the present invention, all or some of the plurality of intermediate layers may be the same layer or different layers ( The resin composition and layer thickness which comprise a layer may differ. Further, the outermost layer of the base layer portion is not particularly limited, and may be the center layer or the intermediate layer.

<Center layer>
The center layer is a layer containing 50% by weight or more of polystyrene resin in the layer.

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

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

  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 grafted with styrene on synthetic rubber; in the continuous phase of a copolymer of styrene monomer and (meth) acrylate monomer Polystyrene (graft-type impact-resistant polystyrene) in which a rubber-like elastic body is dispersed and the copolymer is graft-polymerized to the rubber-like elastic body. Of emissions "graft TIPS"), such as styrene elastomer. Among the polystyrene resins, styrene-diene copolymers are preferable. The polystyrene resin includes hydrogenated polystyrene resin (hydrogenated polystyrene resin). The hydrogenated polystyrene resin is not particularly limited, but a hydrogenated styrene-diene copolymer is 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-based 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 interlayer strength. In addition, the said diene may use only 1 type and may use 2 or more types.

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

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

  Examples of the styrene-diene copolymer include styrene-butadiene block copolymers such as styrene-butadiene-styrene block copolymer (SBS), and styrene such as styrene-isoprene-styrene block copolymer (SIS). -Isoprene block copolymers, styrene-butadiene-isoprene block copolymers such as styrene-butadiene / isoprene-styrene block copolymers (SBIS), etc., among which styrene-butadiene block copolymers are preferred, especially SBS is preferred. In addition, these copolymers may use only 1 type and may use 2 or more types.

  The block copolymer of the styrene-diene copolymer (styrene-diene block copolymer) can be produced by a known and commonly used 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 and commonly used method.

  The styrene-diene copolymer is not particularly limited, but the content of structural units derived from the styrene monomer is 50 with respect to the total weight (100% by weight) of the styrene-diene copolymer. It is preferable that it is -95 weight%, More preferably, it is 60-90 weight%. When the content is 50% by weight or more, the shrink film is suitably hardened, the rigidity of the shrink label is moderately high, and the shrinkage property when the shrink label is attached is good, which is preferable. It is preferable for the content to be 95% by weight or less because appropriate shrinkage stress and shrinkage characteristics can be obtained.

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

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

The content of the structural unit derived from the styrene monomer and the content of the structural unit derived from the diene are the compositions of the styrene-diene copolymer (each styrene-diene copolymer contained in each styrene-diene copolymer). The content of the structural unit and the content of each styrene-diene copolymer in all the styrene-diene copolymers contained in the central 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. The same applies to the content of the structural unit derived from the styrene monomer of the styrene-diene copolymer in the intermediate layer and the content of the structural unit derived from the diene.
Content (% by weight) of structural unit derived from styrenic monomer = (s ₁ × W ₁ + s ₂ × W ₂ ) / 100
Content (% by weight) of structural unit derived from diene = (d ₁ × W ₁ + d ₂ × W ₂ ) / 100

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

  A commercially available product may be used as the polystyrene resin. Examples of commercially available products include “Clearen 530L”, “Clearen 730L” manufactured by Denki Kagaku Kogyo Co., Ltd., “Toughprene 126S” manufactured by Asahi Kasei Co., Ltd., “Asaprene T411”, “Clayton D1102A” manufactured by Clayton Polymer Japan Co., Ltd. , “Clayton D1116A”, “Styrolox S”, “Styrolox T” manufactured by Stylorus Corporation, “Asaflex 840” (above, SBS) manufactured by Asahi Kasei Chemicals, “679” manufactured by PS Japan Co., Ltd. "HF77", "SGP10", DIC Corporation "Dick Styrene XC-515", "Dick Styrene XC-535" (GPPS), PS Japan KK "475D", "H0103", "HT478" ", DIC Corporation" Dick Styrene GH-830 -5 "(or, HIPS) and the like.

  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. Examples include coalescence (SEPS). Commercially available products may be used as the hydrogenated polystyrene resin. For example, “Tough Tech H Series” manufactured by Asahi Kasei Chemicals Corporation, “Clayton G Series” manufactured by Shell Japan Co., Ltd. (hereinafter referred to as SEBS), JSR Corporation “Dynalon” (hydrogenated styrene-butadiene random copolymer), “Kuraray” “Septon” (SEPS), and the like are available on the market.

  In addition, the said polystyrene type resin may use only 1 type, and may use 2 or more types. For example, from the viewpoint of improving impact resistance, shrink performance, and rigidity of the center layer, the polystyrene resin is at least one selected from the group consisting of a styrene-diene copolymer, GPPS, HIPS, and graft TIPS. What mixed the polystyrene-type resin of this can be used.

  The content of the polystyrene-based resin in the center layer is 50% by weight or more (for example, 50 to 100% by weight), preferably 60% by weight or more with respect to the total weight (100% by weight) of the center layer. . When the above content is 50% by weight or more, the shrink finish of the shrink label is good, the wrinkle is difficult to be formed at the time of shrink processing, the shrink property is excellent, and the shrink label after the shrink processing follows the perforation. It becomes easy to cut. In the case where two or more kinds of polystyrene resins are contained in the central layer, the above-mentioned “content of polystyrene resins in the central layer” is the content of all polystyrene resins contained in the central layer. Total amount.

  When the polystyrene resin is a mixture of a styrene-diene copolymer and one or more polystyrene resins selected from the group consisting of GPPS, HIPS, and graft TIPS, GPPS, HIPS, and graft TIPS Although the total content of is not particularly limited, it is 5 to 40 wt.% With respect to the total weight (100 wt.%) Of the central layer from the viewpoints of film stretching characteristics, shrink label rigidity, flexibility, and impact resistance. % Is preferred. In addition, the content of the styrene-diene copolymer in this case is not particularly limited, but is preferably 40 to 95% by weight with respect to the total weight (100% by weight) of the center layer.

  The center layer is not particularly limited, but may contain a resin other than the polystyrene resin. Examples of the resin other than the polystyrene resin include polyester resins and polyolefin resins. Only one type of resin other than the polystyrene-based resin may be used, or two or more types may be used.

  The polyester-based resin (that is, the polyester-based resin that may be included in the central layer) is not particularly limited, and examples thereof include the polyester-based resins exemplified and described as the polyester-based resin included in the surface layer. It is done. The polyester resin may be the same polyester resin as the polyester resin contained in the surface layer or may be a different polyester resin, but the surface layer and the central layer of the base layer portion are In the case of direct lamination, the same polyester resin is preferable from the viewpoint of improving the adhesion between the surface layer and the base layer.

  As the polyester resin (that is, the polyester resin that may be contained in the center layer), a modified aromatic polyester resin is particularly preferable. The aromatic polyester resin is preferably a substantially amorphous aromatic polyester resin, more preferably an aromatic polyester resin that is an amorphous saturated polyester resin.

  Among the above aromatic polyester resins, modified aromatic polyester resins are preferable, more preferably CHDM copolymerized PET, 2,2-dialkyl-1,3-propanediol copolymerized PET (particularly, NPG copolymerized PET). ).

  As the polyester resin (that is, the polyester resin that may be included in the center layer), a commercially available product may be used. As a commercial item, the polyester type resin illustrated and demonstrated as a commercial item of the polyester type resin contained in the above-mentioned surface layer is available on the market, for example.

  The content of the polyester-based resin is not particularly limited, but may be 5% by weight or more with respect to the total weight (100% by weight) of the center layer from the viewpoint of adhesion to the surface layer, shrinkage characteristics, and the like. Preferably, it is 10% by weight or more. The upper limit of the content is not particularly limited, but is preferably less than 50% by weight, more preferably 40% by weight or less, and still more preferably 30% by weight or less.

  Examples of the polyolefin resin include polyethylene resins such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and metallocene catalyst LLDPE (mLLDPE), polypropylene, propylene-α-olefin copolymer, and the like. Polypropylene resin, ethylene-vinyl acetate copolymer, cyclic olefin resin, and the like.

  The central 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. Moreover, the center layer may contain the collection | recovery raw material formed by re-pelletizing the film piece at the time of film manufacture.

<Intermediate layer>
The intermediate layer is not particularly limited as long as it can be laminated with the surface layer, the intermediate layer, or both. In particular, the intermediate layer is preferably a layer (adhesive layer) for improving the adhesion between the surface layer and the center layer. When the adhesive layer is included in the outermost layer of the base layer portion, the adhesion between the surface layer and the central layer of the base layer portion can be improved, and delamination can be made difficult to occur. In addition, since the adhesiveness is not impaired even if the intermediate layer is interposed between the central layers, the contraction speed can be optimized by interposing the intermediate layer between the central layers in the base layer portion. It can also be used to increase the rigidity of the shrink label.

  The intermediate layer is not particularly limited as long as it can be laminated with the surface layer, the intermediate layer, or both. Although the said intermediate | middle layer is not specifically limited, For example, it is preferable that it is a resin layer containing a polystyrene-type resin and / or a polyester-type resin as an essential component.

  The adhesive layer is not particularly limited. For example, a resin layer mainly composed of a mixed resin of a polystyrene resin and a polyester resin, a soft polystyrene resin and / or a resin layer mainly composed of a modified polystyrene resin, a soft layer Examples thereof include a resin layer mainly composed of a polyester-based resin (for example, polyethylene terephthalate to which a plasticizer is added). The adhesive layer is preferably a resin layer mainly composed of a mixed resin of a polystyrene resin and a polyester resin, or a resin layer mainly composed of a soft polystyrene resin and / or a modified polystyrene resin. When the adhesive layer is a resin layer mainly composed of a mixed resin of a polystyrene resin and a polyester resin, the polystyrene resin of the center layer is the polystyrene resin of the adhesive layer, and the polyester resin of the surface layer is the adhesive layer. This is preferable because it can be bonded to each polyester resin and the adhesion between the base layer portion and the center layer of the surface layer is improved.

  When the adhesive layer is a resin layer mainly composed of a mixed resin of a polystyrene resin and a polyester resin, the polystyrene resin (that is, the polystyrene resin contained in the mixed resin) is not particularly limited. The polystyrene resins exemplified and described as the polystyrene resins contained in the above-mentioned center layer can be mentioned. The polystyrene resin may be the same polystyrene resin as the polystyrene resin contained in the center layer or may be a different polystyrene resin, but the surface layer, the base layer portion, and the center layers From the viewpoint of adhesiveness, the same polystyrene resin is preferable. Among these polystyrene resins, styrene-diene copolymers and styrene elastomers (particularly styrene-diene copolymer elastomers) are preferable.

  Although it does not specifically limit as said styrene-diene-type copolymer, For example, the styrene-diene-type copolymer illustrated and demonstrated as a polystyrene-type resin contained in the above-mentioned center layer is mentioned. Of these, styrene-butadiene block copolymers are preferable, and SBS is particularly preferable.

  The styrene-diene copolymer is not particularly limited, but from the viewpoint of shrinkage characteristics and rigidity, the content of the structural unit derived from the styrene monomer is such that the total weight of the styrene-diene copolymer (100 % By weight) is preferably 50 to 95% by weight, more preferably 60 to 90% by weight.

  The styrene-diene copolymer is not particularly limited, but from the viewpoint of shrinkage characteristics and rigidity, the content of the structural unit derived from diene is the total weight (100% by weight) of the styrene-diene copolymer. On the other hand, it is preferable that it is 5 to 50 weight%, More preferably, it is 10 to 40 weight%.

  The glass transition temperature (Tg) of the styrene-diene copolymer is not particularly limited, but is preferably 50 ° C. or higher (for example, 50 to 80 ° C.), more preferably 60 ° C. from the viewpoint of the stretch characteristics of the shrink film. It is above (for example, 60-80 degreeC).

  A commercially available product may be used as the polystyrene resin (that is, the polystyrene resin contained in the mixed resin). As a commercial item, the polystyrene type resin illustrated and demonstrated as a commercial item of the polystyrene type resin contained in the above-mentioned center layer is available on the market, for example.

  Although it does not specifically limit as said polyester resin (namely, polyester resin contained in the said mixed resin), The polyester resin etc. which were illustrated and demonstrated as a polyester resin contained in the above-mentioned surface layer are mentioned. The polyester resin may be the same polyester resin as the polyester resin contained in the surface layer, or may be a different polyester resin, but improves the adhesion between the surface layer and the base layer portion. From the viewpoint of making them, the same polyester resin is preferable. The polyester resin may be the same polyester resin as the polyester resin that may be included in the center layer, or may be a different polyester resin.

  As the polyester resin (that is, the polyester resin contained in the mixed resin), a modified aromatic polyester resin is particularly preferable. The aromatic polyester resin is preferably a substantially amorphous aromatic polyester resin, more preferably an aromatic polyester resin that is an amorphous saturated polyester resin.

  Among the above aromatic polyester resins, modified aromatic polyester resins are preferable, more preferably CHDM copolymerized PET, 2,2-dialkyl-1,3-propanediol copolymerized PET (particularly, NPG copolymerized PET). ).

  A commercially available product may be used as the polyester resin (that is, the polyester resin contained in the mixed resin). As a commercial item, the polyester type resin illustrated and demonstrated as a commercial item of the polyester type resin contained in the above-mentioned surface layer is available on the market, for example.

  When the adhesive layer is a resin layer mainly composed of a mixed resin of a polystyrene resin and a polyester resin, the content of the mixed resin (that is, the total content of the polystyrene resin and the polyester resin) is: Although not particularly limited, it is preferably 50% by weight or more based on the total weight (100% by weight) of the adhesive layer from the viewpoint of improving the adhesion between the surface layer and the base layer part and suppressing delamination. Preferably it is 60 weight% or more, More preferably, it is 70 weight% or more. The upper limit of the content is not particularly limited, but may be 100% by weight or less.

  When the adhesive layer is a resin layer mainly composed of a mixed resin of polystyrene resin and polyester resin, the content of the polystyrene resin is not particularly limited, but improves the adhesion between the surface layer and the base layer portion. From the viewpoint of suppressing delamination, the content is preferably 10 to 90% by weight, more preferably 20 to 80% by weight, based on the total weight (100% by weight) of the adhesive layer. Moreover, the content of the polyester-based resin is not particularly limited, but from the viewpoint of improving the adhesion between the surface layer and the base layer portion and suppressing delamination, the total weight of the adhesive layer (100 wt%), It is preferable that it is 10 to 90 weight%, More preferably, it is 20 to 80 weight%.

  In the case where the adhesive layer is a resin layer mainly composed of a soft polystyrene resin and / or a modified polystyrene resin, the soft polystyrene resin has an adhesive property between the surface layer and the central layer of the base layer portion due to the softness. There is no particular limitation as long as it can be used as a polystyrene-based resin for improving the viscosity. Although it does not specifically limit as said soft polystyrene resin, It is preferable that it is a polystyrene resin softer than the polystyrene resin used for the center layer. Although it does not specifically limit as said soft polystyrene resin, For example, styrene-type elastomer, a styrene-diene-type copolymer, HIPS (high impact polystyrene) with many rubber components, graft TIPS with many rubber components, etc. are mentioned. Of these, styrene elastomers and styrene-diene copolymers are preferable. In addition, the said soft polystyrene type resin may use only 1 type, and may use 2 or more types. 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 TIPS having a large amount of the rubber component refers to a graft TIPS in which the content of the rubber component exceeds 30% by weight with respect to the total weight (100% by weight) of the graft TIPS.

  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. It refers to a copolymer, preferably 60 to 95% by weight, more preferably 65 to 90% by weight.

  The glass transition temperature (Tg) of the styrene-diene copolymer elastomer is not particularly limited, but is preferably 20 ° C. or less, more preferably from the viewpoint of adhesion between the surface layer and the base layer portion, or the center layer. It is 10 ° C. or lower, more preferably 0 ° C. or lower.

  When the polystyrene resin contained in the central layer is a styrene-diene copolymer, the styrene-diene copolymer (that is, the styrene-diene copolymer as the soft polystyrene resin) is The content of the structural unit derived from the styrene monomer is, for example, all the styrene-diene copolymer contained in the adhesive layer as long as it is more flexible than the polystyrene resin used for the central layer. It is preferable that it is 50 to 95 weight% with respect to the total weight (100 weight%) of coalescence, More preferably, it is 60 to 90 weight%. On the other hand, the content of the structural unit derived from diene is 5% by weight or more and less than 50% by weight with respect to the total weight (100% by weight) of all the styrene-diene copolymers in the adhesive layer. Preferably, it is 10 to 40% by weight. In particular, when a styrene-diene copolymer is used as a main component as the central layer, the diene content is preferably higher than that of the styrene-diene copolymer used in the central layer.

  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 polystyrene resin introduced with the polar group includes a hydrogenated polystyrene resin introduced with a polar group. 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 resin has a polar group that has high affinity or can react with the polyester resin contained in the surface layer, and is compatible with the polystyrene resin contained in the center layer. This is preferable because the adhesiveness between the layer and the base layer is increased, and the adhesiveness between the center layers is increased. Only 1 type may be used for the said functional group, and 2 or more types may be used for it.

  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.

  A commercially available product may be used as the modified polystyrene resin. Commercially available products include, for example, “Tough Tech M Series” manufactured by Asahi Kasei Chemicals Corporation, “Epofriend” manufactured by Daicel Corporation, “Polar Group Modified Dynalon” manufactured by JSR Corporation, and “Reseda” manufactured by Toagosei Co., Ltd. Etc.

  When the adhesive layer is a resin layer mainly composed of a soft polystyrene resin and / or a modified polystyrene resin, the total content of the soft polystyrene resin and the modified polystyrene resin is not particularly limited. From the viewpoint of improving the adhesion between the layer and the base layer part and suppressing delamination, it should be 50% by weight or more (for example, 50 to 100% by weight) with respect to the total weight (100% by weight) of the adhesive layer. Preferably, it is 60 to 90% by weight.

  For the purpose of improving the adhesion between the surface layer and the base layer part, the adhesive layer may further include, for example, a rosin resin, a hydrogenated rosin resin, a terpene resin, a terpene-phenol resin, a hydrogenated resin. Terpene resins, coumarone resins, hydrogenated coumarone resins, and tackifying resins such as petroleum resins; polyolefin resins; aromatic hydrocarbon resins; phenol resins; alicyclic hydrocarbon resins; styrene-acrylic copolymer Copolymer; ethylene-vinyl acetate copolymer (EVA); ethylene- (meth) acrylate copolymer and the like may be included. In addition, the intermediate layer may contain other components (additional components) as necessary, for example, lubricants, fillers, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, antifogging agents, flame retardants, A coloring agent, a pinning agent (alkaline earth metal), a softening agent, and the like may be included. These components may use only 1 type and may use 2 or more types. Moreover, the said intermediate | middle layer may contain the collection | recovery raw material formed by re-pelletizing the film piece at the time of film manufacture.

<Configuration of base layer>
The base layer in the shrink film of the present invention has at least one central layer. Moreover, the said base layer part may have an intermediate | middle layer with the said center layer. When the base layer portion includes the center layer and the intermediate layer, the base layer portion is not particularly limited. However, from the viewpoint of increasing the rigidity of the shrink label, it is preferable to include the plurality of center layers via the intermediate layer. In this case, it is preferable that the center layer and the intermediate layer are alternately stacked, and are directly stacked without any layers other than the center layer and the intermediate layer. When the base layer portion has one central layer, examples of such a base layer portion include a single-layer configuration consisting of only one central layer, and an intermediate layer provided on each side of the central layer [intermediate layer / center A three-layer structure having a structure of [layer / intermediate layer].

  When the base layer portion has a plurality of central layers via the intermediate layer, the upper limit of the total number of the central layer and the intermediate layer contained in the base layer portion is not particularly limited, but 65 layers or less are preferable, More preferably, it is 33 layers or less. Increasing the number of layers is preferable because the shrink label has high rigidity. On the other hand, when the number of layers exceeds 65, the thickness of the center layer and / or the intermediate layer (thickness per layer) is thin when the thickness (total thickness) of the shrink film is within a range suitable for the shrink label. The effect of using the center layer and / or the intermediate layer becomes small, the rigidity of the shrink film and the shrink label is lowered, and the waist may be weakened. Moreover, the transparency of the shrink film may be reduced.

  Moreover, when the said base layer part contains a center layer and an intermediate | middle layer, the minimum of the total number of layers of a center layer and an intermediate | middle layer is not specifically limited. In addition, when it is desired to increase the rigidity of the shrink film or the shrink label, the number of the central layers is not particularly limited, but is preferably 2 layers or more, more preferably 4 layers or more. Further, the total number of the central layer and the intermediate layer in this case is not particularly limited, but is preferably 5 layers or more, more preferably 9 layers or more.

  That is, when the base layer portion has a plurality of central layers via the intermediate layer, it is particularly preferable that the base layer portion includes 5 to 65 layers in total, alternately including the central layer and the intermediate layer.

  The upper limit of the number of central layers contained in the base layer is not particularly limited, but is preferably 32 layers or less, more preferably 16 layers or less. Further, the upper limit of the number of the intermediate layers contained in the base layer is not particularly limited, but is preferably 33 layers or less, more preferably 17 layers or less.

  When the base layer portion includes a center layer and an intermediate layer, the stack configuration of the base layer portion is specifically a stack configuration in which “intermediate layer / center layer” is repeated as a repeating unit (intermediate layer / center layer / intermediate layer). / Center layer /... / Intermediate layer / center layer / intermediate layer). Further, the outermost layers on both surfaces of the base layer portion may be a central layer or an intermediate layer, but from the viewpoint of improving the adhesion between the surface layer and the base layer portion and preventing delamination. A layer is preferred.

  Although not particularly limited, in the laminated structure of the base layer portion, it is preferable that all the central layers are formed from the same raw material, and it is preferable that all the intermediate layers are formed from the same raw material. That is, the center layers and the intermediate layers are preferably formed from the same raw material. In particular, all the central layers are preferably layers having the same composition, and all the intermediate layers are preferably layers having the same composition.

(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 said surface layer is laminated | stacked on the both surfaces side of the said base layer part, and is provided in the one surface side and the other surface side, respectively.

  The thickness (total thickness) of the shrink film of the present invention is 15 to 35 μm, preferably 15 to 30 μm. When the thickness is 35 μm or less, the shrink label becomes thin, leading to cost reduction and resource saving.

  The total thickness of the surface layer is 40% or more, preferably 50% or more, particularly preferably more than 50%, with respect to the thickness (total thickness) of the shrink film of the present invention. When the thickness is 40% or more, a shrink film excellent in solvent resistance can be obtained even if the thickness is reduced. The upper limit of the thickness is not particularly limited, but is preferably 75% or less.

  In addition, when the said solvent drying type printing layer is provided only in the one surface side of the shrink film of this invention, it has the said solvent drying type printing layer among the surface layers which have both surfaces of the said base layer part. The surface layer on the side may be a layer thicker than the thickness of the surface layer on the side where the solvent-dried printing layer is not provided. In the case where the solvent-dried printing layer is provided on both sides of the shrink film of the present invention, the surface layer on the side having more of the solvent-drying printing layer (for example, printing with a larger number of colors). The surface layer on the side where the layer is provided may be a layer thicker than the thickness of the surface layer on the side where the solvent-dried printing layer is few.

  Of the above surface layers, the thickness of the surface layer on the side having the solvent-dried printing layer is not particularly limited, but from the viewpoint of improving the solvent resistance against the solvent-drying ink forming the printing layer, the present invention. 20% or more is preferable with respect to the thickness (total thickness) of the shrink film, and more preferably 25% or more. The upper limit of the thickness is not particularly limited, but is preferably 70% or less.

  The thickness of the base layer is not particularly limited, but the thickness (total thickness) of the shrink film of the present invention is from the viewpoint that the shrink finish of the shrink label, the shrink characteristics, and the shrink label after shrink processing is easily cut along the perforation. ) Is preferably 20 to 60%, more preferably 25 to 50%.

  The total thickness of the center layer is not particularly limited, but is 20% by weight or more (for example, 20 to 55%) with respect to the thickness (total thickness) of the shrink film of the present invention from the viewpoint of shrink finish of the shrink label. ) Is preferred, more preferably 20-45%.

  When the base layer portion contains the intermediate layer, the total thickness of the intermediate layer is not particularly limited, but from the viewpoint of adhesion between the surface layer and the center layer of the base layer portion, the thickness of the shrink film of the present invention ( The total thickness is preferably 5% or more (for example, 5 to 40%), and more preferably 5 to 30%.

  The thickness of the surface layer (the thickness of one layer) is not particularly limited, but is preferably 5 μm or more (for example, 5 to 15 μm). When the thickness is 5 μm or more, it is possible to improve the solvent resistance with respect to the solvent-drying ink for forming the printed layer, which is preferable. In addition, the thickness of the surface layer of the one surface side and other surface side in the shrink film of this invention may be the same, and may mutually differ. In addition, when the thicknesses of the surface layer on the one surface side and the other surface side are different from each other, the thickness of the surface layer on the side having the solvent-dried printing layer may be 5 μm or more.

  Although the thickness of the said base layer part is not specifically limited, From a viewpoint of the shrink finish finish of a shrink label, 5 micrometers or more (for example, 5-30 micrometers) are preferable.

  The thickness of the central layer (thickness of one layer) is not particularly limited, but is preferably 0.3 μm or more (for example, 0.3 to 30 μm), more preferably 0.3 from the viewpoint of shrink finish of the shrink label. ˜20 μm. In addition, as for the thickness of the some center layer in the shrink film of this invention, all or one part of them may be the same, and may mutually differ.

  When the said base layer part contains an intermediate | middle layer, although the thickness (thickness of 1 layer) of the said intermediate | middle layer is not specifically limited, 0.2 micrometer or more (for example, 0.2-7 micrometers) is preferable. In addition, as for the thickness of the some intermediate | middle layer in the shrink film of this invention, all or one part of them may be the same, and may mutually differ. For example, the intermediate layer of the base layer portion in contact with the surface layer may be thinner than the intermediate layer in the base layer portion (intermediate layer between the central layers).

  The ratio of the thickness of the central layer (total thickness of all central layers) and the thickness of the intermediate layer (total thickness of all intermediate layers) [(central layer thickness) :( intermediate layer thickness)] is: Although it does not specifically limit, 1: 1-10: 1 are preferable, More preferably, it is 1: 1-8: 1, Especially preferably, it is 1: 1-5: 1. When the above ratio is thinner than 1: 1, the thermal shrinkage rate may be reduced, or the proper shrinkage rate and rigidity may not be achieved. On the other hand, if the intermediate layer is thinner than 10: 1, the surface layer and the base layer may be delaminated.

  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 (surface layer, center layer, intermediate layer) are films oriented in at least a uniaxial direction. 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. It is obtained by stretching. 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 tensile property (conforming to JIS K 7127) in the direction orthogonal to the main orientation direction of the shrink film of the present invention is not particularly limited, but is preferably 200% or more, more preferably 250% or more. It is preferable for the tensile properties to be 200% or more, since breakage at the time of applying solvent-drying type ink to the shrink film can be suppressed, and the manufacturing suitability of the shrink label can be improved. The above-mentioned “main orientation direction” is a direction mainly subjected to a stretching process (a direction having the largest thermal shrinkage), and is generally a longitudinal direction or a width direction, for example, substantially in the width direction. In the case of a film uniaxially stretched (substantially a uniaxially oriented film in the width direction), it is the width direction.

  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.

  The haze (haze) value [conforming to JIS K 7136, converted to a thickness of 40 μm, unit:%] of the shrink film of the present invention is preferably less than 10%, more preferably less than 7%, and still more preferably less than 5%. When the haze value is 10% or more, printing is performed on the inside of the shrink film (the side that becomes the container side when the shrink label is attached to the container), and the shrink label that shows the print through the shrink film is the product. In some cases, the printing may become cloudy and the decorativeness may deteriorate. However, even when the haze value is 10% or more, it can be sufficiently used in applications other than the above-described applications that show printing through a shrink film.

[Shrink label]
The shrink label of the present invention is a shrink label having a solvent-dried printing layer on at least one surface of 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 and the solvent-dried printing layer.

(Solvent-dried printing layer)
The solvent-drying type printing layer is a printing layer formed with solvent-drying type ink.

  The solvent-dried printing layer is not particularly limited as long as it is a printing layer formed with a solvent-drying ink. For example, a printing layer formed with a known solvent-drying ink used in a shrink label or the like. Can be mentioned. Examples of the solvent-dried printing layer include design printing layers (color printing layers, etc.) such as product names, illustrations, handling precautions, etc., and background printing formed in a single color such as white. Examples thereof include a protective printing layer provided for protecting a layer, a film and a printing layer, and a primer printing layer provided for improving the adhesion between the film and the printing layer. The solvent-dried printing layer is not particularly limited, but may be provided only on one side of the shrink film of the present invention, or may be provided on both sides of the shrink film of the present invention. The solvent-dried printing layer may be provided on the entire surface of the shrink film of the present invention (the surface on the side on which the printing layer is provided) or may be provided in part. Further, the solvent-dried printing layer is not particularly limited, but may be a single layer or a multilayer.

  The solvent-dried printing layer is not particularly limited, but preferably contains a binder resin as an essential component. Furthermore, it is preferable to include colored pigments such as blue, red, yellow, black, and white as necessary. Each of the binder resin and the color pigment may be used alone or in combination of two or more.

  It does not specifically limit as said binder resin, For example, resin used as binder resin in a well-known printing layer and 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 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.

  The solvent dry printing layer is not particularly limited, but a solvent (solvent) of solvent dry ink may remain. That is, the solvent dry printing layer is not particularly limited, but may contain a solvent as a residual solvent. As said solvent, the organic solvent etc. which are normally used for the printing ink used for gravure printing, flexographic printing, etc. are mentioned. Examples of the solvent include esters such as acetate (eg, ethyl acetate, propyl acetate, butyl acetate); alcohols such as methanol, ethanol, isopropyl alcohol, propanol, and butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; toluene, Aromatic hydrocarbons such as xylene; aliphatic hydrocarbons such as hexane and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; glycols such as ethylene glycol and propylene glycol; ethylene glycol monopropyl ether, propylene glycol monomethyl ether, Glycol ethers such as propylene glycol monobutyl ether; Glycol ether esters such as propylene glycol monomethyl ether acetate And the like. Among these, from the viewpoint of exhibiting excellent solvent resistance of the shrink film of the present invention, esters and alcohols are preferable, acetate esters and alcohols are more preferable, and ethyl acetate, propyl acetate and isopropyl alcohol are more preferable. The solvent-dried printing layer is not particularly limited, but it is preferable that isopropyl alcohol is detected as the main component. The solvent (solvent) includes the meaning of “dispersion medium”.

  In the solvent-dried printing layer, the content of the aromatic hydrocarbon is not particularly limited, but is preferably 1% by weight or less with respect to the total residual solvent (100% by weight).

  Although the thickness of the said solvent dry type 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, the shrink label is likely to be cut, and a large amount of printing ink is consumed, which increases the cost, makes it difficult to apply uniformly, and makes the printed layer brittle. In some cases, the printing layer may not easily follow the heat shrinkage of the shrink film during shrink processing.

(Layers other than the shrink film and solvent-dried printing layer of the present invention)
Layers other than the shrink film of the present invention and the solvent-dried printing layer included in the shrink label of the present invention are not particularly limited, but other film layers such as nonwoven fabrics and foam sheets, adherends of shrink labels Adhesive layer (pressure-sensitive adhesive layer, heat-sensitive adhesive layer, etc.) for bonding to and other film layers, printing layers other than the above-mentioned solvent-drying type printing layers, coatings other than the above-mentioned solvent-drying type printing layers A layer, an antistatic layer, an aluminum vapor deposition layer, and the like.

  1 to 3 are schematic views (cross-sectional views) each showing an example of the shrink label of the present invention. The shrink label 3 of the present invention shown in FIG. 1 includes the shrink film 1 of the present invention and a solvent-drying type printing layer 2 provided on one side of the shrink film 1 of the present invention. The shrink film 1 of the present invention includes a base layer portion 12 and a surface layer 11 provided on each side of the base layer portion 12. The base layer portion 12 is formed of only one central layer 12a. The surface layer 11 and the base layer portion 12 are directly laminated without interposing other layers. Specifically, the surface layer 11 and the center layer 12a are directly laminated without interposing other layers. That is, the shrink film 1 of the present invention has a two-layer / three-layer structure of [surface layer 11 / center layer 12a / surface layer 11].

  The shrink label 3 of the present invention shown in FIG. 2 includes the shrink film 1 of the present invention and a solvent-dried printing layer 2 provided on one side of the shrink film 1 of the present invention, as in FIG. . 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 includes one central layer 12a and intermediate layers 12b provided on both sides of the central layer 12a, and the outermost layer (layer in contact with the surface layer 11) is formed as the intermediate layer 12b. Yes. The surface layer 11 and the base layer portion 12 are directly laminated without interposing other layers. Specifically, the surface layer 11 and the intermediate layer 12b which is the outermost layer of the base layer portion 12 are directly laminated without interposing other layers. That is, the shrink film 1 of the present invention has a three-layer five-layer structure of [surface layer 11 / intermediate layer 12b / center layer 12a / intermediate layer 12b / surface layer 11].

  The shrink label 3 of the present invention shown in FIG. 3 includes a shrink film 1 of the present invention and a solvent-dried printing layer 2 provided on one side of the shrink film 1 of the present invention, as in FIGS. including. Further, the shrink film 1 of the present invention has a surface layer 11 and a base layer portion 12, and the base layer portion 12 has an outermost layer (a layer in contact with the surface layer 11) as an intermediate layer 12 b, and a center layer 12 a and an intermediate layer. 12b are alternately stacked in a total of nine layers. 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 intermediate layer 12 b that is the outermost layer of the base layer portion 12 are interposing other layers. There is no direct lamination. That is, the shrink film 1 of the present invention has [surface layer 11 / intermediate layer 12b / center layer 12a / intermediate layer 12b / center layer 12a / intermediate layer 12b / center layer 12a / intermediate layer 12b / center layer 12a / intermediate layer 12b. / Surface layer 11] has three layers and 11 layers.

  Although the thickness (total thickness) of the shrink label of this invention is not specifically limited, 50 micrometers or less are preferable exceeding 15 micrometers, More preferably, it is 20-40 micrometers.

  When the shrink film of the present invention is a film substantially uniaxially stretched in the width direction, the tensile properties (conforming to JIS K 7127) in the direction orthogonal to the main orientation direction of the shrink label of the present invention are not particularly limited. However, 100% or more is preferable, and 150% or more is more preferable from the viewpoint that the shrink label has appropriate shrinkage characteristics.

The content of the residual solvent in the shrink label of the present invention is not particularly limited, but is preferably 200 mg / m ² or less, more preferably 150 mg / m ² or less, and still more preferably 100 mg / m ² or less. Although the minimum of the said content is not specifically limited, It is preferable to exceed 0 mg / m < ² >. When the content is 200 mg / m ² or less, the shrink label is not easily broken even when a relatively strong tension is applied to the shrink label, such as when a label is attached to a bottle when making a shrink label. It is preferable. The solvent is not particularly limited as long as it is a solvent present in the shrink label. For example, the solvent contained in the solvent dry ink is present in the solvent remaining in the printing layer, the shrink film. A solvent etc. are mentioned.

  The content of the residual solvent can be measured by, for example, a gas chromatograph mass spectrometer (GCMS).

  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 tubular shrink label from the viewpoint of excellent solvent resistance against a solvent or an adhesive in a seal portion when the tubular shrink label is mounted on a container. That is, the shrink label of the present invention is preferably a cylindrical shrink label.

  The cylindrical shrink label is formed into a cylindrical shape so that the solvent-dried printing layer (particularly, the solvent-dried design printing layer) is on the inside, and both ends (both ends) of the shrink label. A cylindrical shrink label (hereinafter, sometimes referred to as “cylindrical shrink label of the present invention”) in which a seal portion is formed by superimposing the two is preferable.

  4 and 5 are each a schematic view showing an example of a cylindrical shrink label according to 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 a solvent-dried printing layer. 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 in that direction. Heat shrinkable. 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. The background printing layer 51 and / or the design printing layer 52 are solvent-drying printing layers.

  Examples of the design printing layer include a layer displaying a trade name, an illustration, handling precautions, and the like. Although it does not specifically limit as said design printing layer, For example, the said solvent dry 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, 0.1-5 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 solvent dry type 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 a titanium oxide as a coloring pigment, are preferable. Although the thickness of the said background printing layer is not specifically limited, 0.5-8 micrometers is preferable.

  The shrink film of the present invention used for the shrink label of the present invention has a total thickness of 15 to 35 μm, and has a surface layer containing 50% by weight or more of a polyester resin on both sides of the base layer part, The base layer portion has at least one central layer containing 50% by weight or more of polystyrene-based resin, and the total thickness of the surface layer is 40% or more with respect to the total thickness of the shrink film. The shrink film of the present invention is excellent in solvent resistance even if it is as thin as 15 to 35 μm by setting the total thickness of the surface layer to a specific value or more, and it is solvent-dried on at least one surface of the shrink film. Even if it has a printing layer formed with a mold ink, it is difficult to be attacked by the solvent, so that the shrink label of the present invention can be hardly broken. In addition, the shrink film of the present invention has at least one central layer in the base layer portion, so that the shrink label of the present invention suppresses wrinkles of the shrink label and bending of the end portion caused by rapid shrinkage during heat shrinkage. It also retains the advantage of polystyrene resin.

[Production method of shrink label of the present invention]
The manufacturing method of the shrink label of this invention includes at least the process of preparing the shrink film of this invention, and the process of apply | coating solvent-drying type ink to the shrink film of this invention, and drying and solidifying, and forming a printing layer. In the present specification, the “process for preparing the shrink film of the present invention” may be referred to as a “film preparation process”. In the present specification, the above-mentioned “process for forming a print layer by applying a solvent-drying type ink to the shrink film of the present invention and drying and solidifying it” may be referred to as a “print layer formation process”. Examples of the printing layer formed by the printing layer forming step include a design printing layer, a background printing layer, a protective printing layer, and a primer printing layer. The manufacturing method of the shrink label of this invention may further include other processes, such as the process of forming layers other than the shrink film of this invention, and the said printing layer.

(Film preparation process)
In the said film preparation process, you may purchase and prepare the shrink film of this invention, and may produce and prepare the shrink film of this invention. In this specification, the process of preparing and preparing the shrink film of this invention may be called a "film preparation 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. When the base layer part includes a plurality of central layers and intermediate layers, the base layer part should be multi-layered using a layer multiplier, in particular using a combination of a feed block and a layer multiplier. Is preferred. The layer multiplier is a device that multi-layers film layers. The method of multilayering the film layer with the layer multiplier is not particularly limited, and examples thereof include a method of dividing the film layer in the width direction and then laminating the divided film layer in the thickness direction. In the present specification, the “layer multiplier” may be simply referred to as “multiplier”. The multiplier can be obtained from EDI, for example.

  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. In this case, when the base layer part is a specific repeating unit, it is preferable to use a combination of a feed block and a multiplier to make the base layer part multilayered 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.

  In the film production step, it is preferable to stretch the laminated unstretched film (having a step of stretching) from the viewpoint of exhibiting heat shrinkability. As the stretching, biaxial stretching in the longitudinal direction (the film production line direction; also referred to as the longitudinal direction or MD direction) and the width direction (the direction orthogonal to the longitudinal direction; also referred to as the transverse direction or TD direction), the longitudinal direction or the width. 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. 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 7 times (preferably 4 to 5.5 times).

  In the film preparation step, the surface of the shrink film of the present invention may be subjected to conventional surface treatment such as corona discharge treatment or primer treatment, if necessary.

  When the base layer portion is formed of only one central layer (for example, in the case of the shrink label of the present invention shown in FIG. 1), the film production step includes the raw material (“raw material (a)”) constituting the central layer. And a raw material constituting the surface layer (may be referred to as “raw material (c)”), and the molten raw material is melted on both sides of the raw material (a). At least a step of laminating (c).

  On the other hand, when the base layer portion contains a center layer and an intermediate layer (for example, in the case of the shrink label of the present invention shown in FIGS. 2 and 3), the film production process includes the raw material (a) and the raw material (c ) And the raw material constituting the intermediate layer (sometimes referred to as “raw material (b)”); the raw material (a) and the raw material melted in the first stage; (B) is laminated and further multilayered as necessary to form a laminate; and on both sides of the laminate formed in the second step, the second step It includes at least a third step of laminating the raw materials (c) melted in the first step. 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 and common extruder. For example, the raw material (a), the raw material (b), and the raw material (c) can be charged into three extruders each set at a predetermined temperature, and melted (or melt-kneaded). Although extrusion temperature is not specifically limited, 150-250 degreeC is preferable.

  In the second stage, when the raw material (a) and the raw material (b) melted in the first stage are laminated and further multilayered, a combination of a feed block and a multiplier may be used. preferable. Each of the above feed blocks and multipliers may use only 1 or 2 or more. By the second stage, a laminated body in which the raw material (a) and the raw material (b) are laminated in the first stage, or a laminated body that is further multilayered is obtained. In the laminated body, the total number of layers formed from the raw material (a) and the number of layers formed from the raw material (b) is preferably 3 to 65 layers, more preferably 3 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 laminate obtained by laminating the raw material (a) and the raw material (b) specifically includes, for example, the raw material (a) and the raw material ( b) can be extruded using a feed block to obtain a laminate (may be referred to as “laminate 1”) having a structure of [raw material (b) / raw material (a) / raw material (b)]. . Moreover, the laminated body which laminated | stacked the raw material (a) and the raw material (b), and was further multilayered specifically, laminate | stacks the said laminated body 1 as one unit, for example using a multiplier, [Raw material (b) / Raw material (a) / Raw material (b) / Raw material (b) / Raw material (a) / Raw material (b) /.../ Raw material (b) / Raw material (a) / Raw material (b) ] Can be obtained (sometimes referred to as “laminate 2”).

  In the third stage, the raw material (c) melted in the first stage is laminated on both sides of the laminate (for example, the laminate 1 and the laminate 2) formed in the second stage. When doing so, it is preferable to use a feed block. The laminated raw material (c) forms the surface layer of the shrink film of the present invention. By the third stage, a laminate is obtained in which the raw material (c) melted in the first stage is laminated on both sides of the laminate formed in the second stage.

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

  [Raw material (b) / Raw material (a) / Raw material (b) / Raw material (b) / Raw material (a) / Raw material (b) /.../ Raw material (b) / Raw material (a) / Raw material ( b)] has a structure of [intermediate layer / central layer / intermediate layer / intermediate layer / central layer / intermediate layer /.../ intermediate layer / central layer / intermediate layer]. Although it is a laminated unstretched film, the part of [raw material (b) / raw material (b)] in which the same material of the laminate 2 is actually laminated is the interface between the raw material (b) layer and the raw material (b) layer. Cannot be specified, and the intermediate layer becomes one intermediate layer, so that the intermediate layer / center layer / intermediate layer / center layer /.. ./Intermediate layer / center layer / intermediate layer structure is obtained.

  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.

(Print layer forming process)
In the printing layer forming step, a solvent drying type printing layer is formed by applying solvent drying type ink on at least one surface of the shrink film of the present invention and solidifying by drying. In the printing layer forming step, 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 solvent-drying ink is produced, for example, by mixing the binder resin, the color pigment, the solvent, and other additives (dispersant, etc.) as necessary.

  As the solvent (that is, the solvent contained in the solvent-drying ink), an organic solvent or the like that is usually used in inks used for gravure printing, flexographic printing, and the like can be used. Examples of the solvent include esters such as acetate (eg, ethyl acetate, propyl acetate, butyl acetate); alcohols such as methanol, ethanol, isopropyl alcohol, propanol, and butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; toluene, Aromatic hydrocarbons such as xylene; aliphatic hydrocarbons such as hexane and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; glycols such as ethylene glycol and propylene glycol; ethylene glycol monopropyl ether, propylene glycol monomethyl ether, Glycol ethers such as propylene glycol monobutyl ether; Glycol ether esters such as propylene glycol monomethyl ether acetate And the like. Among these, esters and alcohols are preferred, more preferably acetates, alcohols, and even more preferably ethyl acetate, acetic acid, from the viewpoint of not impairing the printability on the surface layer of the shrink film of the present invention and low attack on the film. Propyl and isopropyl alcohol. That is, the solvent-drying ink preferably contains an ester and / or alcohol (particularly, ethyl acetate, propyl acetate, isopropyl alcohol) as a main component of the solvent.

  The solvent-drying ink is not particularly limited, but the total content of ester and alcohol is 80% by weight or more based on the total solvent (100% by weight) from the viewpoint of low aggressiveness to the film. Is more preferable, and 85% by weight or more is more preferable. The upper limit of the content is not particularly limited, but may be 100% by weight or less.

  The above mixing can be performed by a known and common 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.

(Manufacturing method of cylindrical shrink label)
Although the manufacturing method of a cylindrical shrink label is not specifically limited, For example, it shape | molds in a cylindrical shape so that the main orientation direction of a shrink label (shrink label of this invention) may turn into a circumferential direction. Specifically, both ends of the main orientation direction of the shrink label having a predetermined width in the main orientation direction are overlapped to form a cylinder, and on one side edge portion (the other end portion) of the label, from the end to the belt shape About 2 to 4 mm in width, a solvent such as tetrahydrofuran (THF) or an adhesive (hereinafter sometimes referred to as “adhesive or the like”) is applied to the inner surface, and the adhesive or the like is applied to the other side edge. It adheres to the outer surface of (one end part), and a cylindrical shrink label is obtained.

  In addition, when providing the perforation for label cutting to a cylindrical shrink label, the perforation of predetermined length and a pitch is formed in the 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 process stage for perforating can be selected as appropriate, such as before and after the cylindrical machining process.

[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 composition of the raw material for the surface layer (raw material (c)), the raw material for the central layer (raw material (a)), the raw material for the intermediate layer (raw material (b)) used in the examples and comparative examples, The structures and evaluation results of the shrink films and shrink labels produced in the examples and comparative examples are shown.

(Example of preparation of solvent dry ink)
As a binder resin, urethane acrylic resin solution (manufactured by Taisei Fine Chemical Co., Ltd., trade name “Acryt 8UA-140”, nonvolatile content concentration: 40 wt%, volatile content of 99 wt% ethyl acetate and 1 wt% isopropyl alcohol 2 parts by weight of solvent (containing 60% by weight), acrylic resin (manufactured by Mitsubishi Rayon Co., Ltd., trade name “Dyanal BR-113”, nonvolatile content concentration: 100% by weight), 10 parts by weight, acrylic resin (Mitsubishi Rayon) Product name “Dianar BR-116”, nonvolatile content concentration: 100% by weight), cellulose resin (manufactured by Eastman Chemical, trade name “CAB-381-20”, nonvolatile content concentration) : 100 wt%) 0.5 part by weight was used.
As the coloring pigment, 37 parts by weight of titanium oxide (trade name “JR-707”, nonvolatile concentration: 100% by weight, manufactured by Teika Co., Ltd.) was used.
To the binder resin and the color pigment, 0.5 parts by weight of a dispersant, 0.5 parts by weight of an anti-settling agent, 2 parts by weight of wax, 9 parts by weight of ethyl acetate, 13 parts by weight of n-propyl acetate, propylene glycol monomethyl ether ( 5 parts by weight of PGM) and 19 parts by weight of isopropyl alcohol (IPA) were added to prepare a solvent-drying ink (sometimes referred to as “solvent-drying ink (A)”).
The content of each solvent in the solvent dry ink (A) is about 40% by weight of IPA, about 22% by weight of ethyl acetate, and about 28% by weight of n-propyl acetate with respect to 100% by weight of the total solvent. %, PGM was about 10% by weight.

Example 1
(material)
As a raw material constituting the central layer (a raw material for the central layer), polystyrene resin A (manufactured by Stylorusion, trade name “Styrolux S”, content of structural unit derived from butadiene: 12% by weight), 54% by weight, Polystyrene resin B (manufactured by Styloluson, trade name “Styrolux T”, content of constituent unit derived from butadiene: 26% by weight) 24% by weight, polyester resin A (manufactured by Eastman Chemical, trade name “EMBRACE”) LV ") 22% by weight was used.
As a raw material constituting the intermediate layer (intermediate layer raw material), 100% by weight of polystyrene resin B was used.
As a raw material constituting the surface layer (surface layer raw material), 100% by weight of polyester resin A was used.

(Shrink film)
The raw material for the central layer was charged into the extruder a heated to 220 ° C., the raw material for the intermediate layer was charged into the extruder b heated to 220 ° C., and the raw material for the surface layer was charged into the extruder c heated to 250 ° C. Melt extrusion was performed using the above three extruders. Two types of three-layer construction of intermediate layer raw material / central layer raw material / intermediate layer raw material using a feed block whose molten layer is mixed with the intermediate layer raw material and the molten intermediate layer raw material. The laminated body (I) is prepared, and the melted raw material for the surface layer is merged and laminated using a feed block so as to be on both sides (surface layer) of the laminated body (I). ). Furthermore, after the laminate (II) is extruded from a T-die, it is rapidly cooled on a casting drum cooled to 25 ° C. to have a structure of [surface layer / intermediate layer / center layer / intermediate layer / surface layer]. A five-layer laminated unstretched film (the base layer portion was a three-layer structure of [intermediate layer / center layer / intermediate layer]) was obtained.
Next, the laminated unstretched film is stretched 5 times at 85 ° C. in the width direction so as to be stretched mainly in the width direction, and a stretched film (shrink film) having heat shrinkability in the direction. Got.

(Shrink label)
For the long body of the shrink film obtained above, solvent-dried ink (A) is applied by gravure printing using a gravure printing machine and dried to form a solvent-dried printing layer, A long body of shrink label was obtained. In addition, the content of the residual solvent of the shrink label after one week from the production is 10 mg / m ² , and the ethyl acetate, n-propyl acetate, and PGM which are the solvents contained in the solvent dry ink (A) are used. And all of IPA were detected as residual solvents.

(Cylinder shrink label)
Next, after slitting the long body of the shrink label so as to have a predetermined width, one end and the other end are overlapped to form a cylinder so that the width direction is the circumferential direction. The shrink film surfaces of the part were sealed with a solvent to obtain a cylindrical long body of a shrink label. Furthermore, the cylindrical long body (label continuous body) of the shrink label was cut into individual label sizes to obtain a cylindrical shrink label.

Examples 2-4, Example 7, Comparative Example 1
As shown in Table 1, in the same manner as in Example 1, the shrinkage and shrinkage of the raw material (a), the raw material (b) and the raw material (c) were changed in composition and component ratio, thickness of each layer and shrink film, and the like. Got a label. As the polyester resin B, trade name “EMBRACE 21214” manufactured by Eastman Chemical was used.

Example 5
(material)
Polystyrene resin A 30% by weight and polystyrene resin B 70% by weight were used as the raw material (center layer raw material) constituting the central layer.
Polystyrene resin A 12% by weight, polystyrene resin B 28% by weight, and polyester resin B 60% by weight were used as the raw material constituting the intermediate layer (intermediate layer raw material).
As a raw material constituting the surface layer (surface layer raw material), 100% by weight of polyester resin B was used.

(Shrink film)
The raw material for the central layer was charged into the extruder a heated to 220 ° C., the raw material for the intermediate layer was charged into the extruder b heated to 220 ° C., and the raw material for the surface layer was charged into the extruder c heated to 250 ° C. Melt extrusion was performed using the above three extruders. For the intermediate layer using a laminating apparatus in which the melted raw material for the central layer and the molten intermediate layer material are combined with a feed block that is a two-layer / three-layer type merging method and a four-part multiplier (manufactured by EDI). Dividing, merging and laminating the two-kind three-layer structure of the raw material / the raw material for the central layer / the raw material for the intermediate layer as one repeating unit, a laminate (III) The melted raw material for the surface layer is joined and laminated using a feed block so as to be on both sides (surface layer) of the laminate (III) to obtain a laminate (IV). . Further, after the laminate (IV) was extruded from a T-die, it was rapidly cooled on a casting drum cooled to 25 ° C., and an 11-layer laminated unstretched film (the base layer portion was a repeating unit of 2 types and 3 layers) Since the number of repetitions is four, the number of layers becomes 12 layers, but the portion where the intermediate layer raw materials overlap is actually one layer, so [intermediate layer / center layer / intermediate layer / center layer / intermediate layer / center Layer / intermediate layer / center layer / intermediate layer].
Next, the laminated unstretched film is stretched 5 times at 85 ° C. in the width direction so as to be stretched mainly in the width direction, and a stretched film (shrink film) having heat shrinkability in the direction. Got.

(Shrink label, cylindrical shrink label)
Using the long body of the shrink film obtained above, the long body of the shrink label and the cylindrical shrink label were obtained in the same manner as in Example 1.

Example 6
(material)
Polystyrene resin A21% by weight, polystyrene resin B49% by weight, and polyester resin B30% by weight were used as raw materials constituting the central layer (raw material for the central layer).
As a raw material constituting the surface layer (surface layer raw material), 100% by weight of polyester resin B was used.

(Shrink film)
The raw material for the central layer was charged into the extruder a heated to 220 ° C., and the raw material for the surface layer was charged into the extruder c heated to 250 ° C. Melt extrusion was performed using the above two extruders. The resin extruded from the extruder a becomes a central layer, and the resin extruded from the extruder c is merged using a merge block so as to be a layer on both sides (surface layer), and extruded from a T die (slit interval: 1 mm). Then, it was rapidly cooled on a casting drum cooled to 25 ° C. to obtain a two-kind / three-layer laminated unstretched film having a structure of [surface layer / center layer / surface layer].
Next, the laminated unstretched film is stretched 5 times at 85 ° C. in the width direction so as to be stretched mainly in the width direction, and a stretched film (shrink film) having heat shrinkability in the direction. Got.

(Shrink label, cylindrical shrink label)
Using the long body of the shrink film obtained above, the long body of the shrink label and the cylindrical shrink label 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) Tensile properties (before printing layer formation)
From the shrink films obtained in Examples and Comparative Examples, a rectangular film piece having a width direction (TD direction) of 15 mm and a longitudinal direction (MD direction) of 150 mm was cut out and used as a measurement sample. Two marked lines were drawn at positions of 25 mm from both ends of the measurement sample (both ends in the longitudinal direction) (marked line interval 100 mm).
Using a tensile tester [Shimadzu Corporation, “Shimadzu Autograph (AGS-50G: load cell type 500N)]”, temperature and humidity conditions of temperature 23 ± 2 ° C. and relative humidity 50 ± 5% (% RH) The test was conducted below.
The sample for measurement was attached to the tensile tester having a chuck interval (grip interval) of 100 mm so that the distance between the marked lines was a measurement position (initial length 100 mm). The sample for measurement was pulled by a tensile tester at a tensile speed (test speed) of 200 mm / min until the chuck interval was 300 mm (elongation 200%). Then, the tensile properties were evaluated according to the following criteria. In addition, as for the said tensile characteristic, the number of tests (n number) was set to 5 (n = 5), and the average value was made into the evaluation result.
Good tensile properties (O): No break in measurement sample with elongation of 200% Tensile properties are poor (x): Breakage of measurement sample in elongation of 200% or less

(2) Tensile properties (after printing layer formation)
From the shrink labels obtained in Examples and Comparative Examples, rectangular label pieces having a width direction (TD direction) of 15 mm and a longitudinal direction (MD direction) of 150 mm were cut out and used as measurement samples. Two marked lines were drawn at positions of 25 mm from both ends of the measurement sample (both ends in the longitudinal direction) (marked line interval 100 mm).
Using a tensile tester [Shimadzu Corporation, “Shimadzu Autograph (AGS-50G: load cell type 500N)]”, temperature and humidity conditions of temperature 23 ± 2 ° C. and relative humidity 50 ± 5% (% RH) The test was conducted below.
The sample for measurement was attached to the tensile tester having a chuck interval (grip interval) of 100 mm so that the distance between the marked lines was a measurement position (initial length 100 mm). The sample for measurement was pulled by a tensile tester at a tensile speed (test speed) of 200 mm / min until the chuck interval became 200 mm (elongation 100%). Then, the tensile properties were evaluated according to the following criteria. In addition, as for the said tensile characteristic, the number of tests (n number) was set to 5 (n = 5), and the average value was made into the evaluation result.
Good tensile properties (○): 100% elongation without breakage of measurement sample Unsatisfactory tensile properties (x): Breakage of measurement sample with elongation of 100% or less

(3) Shrink verification (shrinkage characteristics)
The cylindrical shrink labels obtained in the examples and comparative examples were externally fitted in containers (500 ml round PET containers manufactured by Toyo Seikan Co., Ltd.), and then passed through a 90 ° C. steam tunnel to form cylindrical shrink labels. The label was heat-shrinked to obtain a labeled container (the heat shrinkage rate at the container body was 5%). The occurrence frequency of wrinkles on the label of the labeled container was confirmed at n = 10. And the shrinkage | contraction characteristic was evaluated on the following references | standards.
Out of 10 wrinkles: Good (○)
Out of 10 wrinkles or more: Defective (×)

  As can be seen from Table 1, the shrink labels (Examples 1 to 7) of the present invention were excellent in the solvent resistance of the shrink film, and excellent in tensile properties before and after the formation of the printing layer. Moreover, the shrinkage | contraction characteristic was excellent. On the other hand, in the shrink label (Comparative Example 1) having a shrink film in which the total thickness of the surface layer is less than 40% with respect to the total thickness of the shrink film, the shrink film is more resistant to solvents than the shrink film of the present invention. The tensile properties were inferior after the printing layer was formed.

DESCRIPTION OF SYMBOLS 1 Shrink film of this invention 11 Surface layer 12 Base layer part 12a Center layer 12b Intermediate | middle layer 2 Solvent dry printing layer 3 Shrink label of this invention 4 Cylindrical shrink label of this invention 41 Sealing part D Circumferential direction 51 Background printing layer 52 Design printing layer 53 Solvent or adhesive

Claims (7)

A shrink label having a printed layer on at least one side of a shrink film,
The total thickness of the shrink film is 15 to 35 μm,
The shrink film has a base layer and a surface layer containing 50% by weight or more of a polyester resin on both sides of the base layer,
The base layer portion has at least one central layer containing 50% by weight or more of a polystyrene-based resin,
The total thickness of the surface layer is 40% or more with respect to the total thickness of the shrink film,
A shrink label, wherein the printing layer is a solvent drying type printing layer.   The shrink label according to claim 1, wherein the solvent-dried printing layer contains an ester and / or alcohol as a residual solvent.   The shrink label according to claim 1 or 2, wherein a total thickness of the center layer is 20% or more with respect to a total thickness of the shrink film.   The shrink label according to claim 1, wherein the base layer portion includes the center layer and an intermediate layer.   The shrink label according to claim 4, wherein the base layer portion includes the central layer and the intermediate layer alternately in a total of 5 to 65 layers. A method for producing a shrink label having a printed layer on at least one of the shrink films,
The total thickness of the shrink film is 15 to 35 μm,
The shrink film has a base layer and a surface layer containing 50% by weight or more of a polyester resin on both sides of the base layer,
The base layer portion has at least one central layer containing 50% by weight or more of a polystyrene-based resin,
Preparing a shrink film having a total thickness of the surface layer of 40% or more with respect to the total thickness of the shrink film;
A method for producing a shrink label, comprising: applying a solvent-drying type ink to the shrink film and drying and solidifying the ink to form a printed layer.   The method for producing a shrink label according to claim 6, wherein the solvent-drying ink contains an ester and / or alcohol as a solvent, and a total content of the ester and the alcohol is 80% by weight or more based on the total solvent.

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