JP2008201463A - Shrink label and labeled container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superior shrink label that has no decrease in decorative property, such as cloudiness, after a shrinking process to obtain a beautifully-finished container, and has no decrease in gas barrier characteristic after the shrinking process. <P>SOLUTION: The shrink label has at least a recording layer including pigments, an anchor coat layer, and a barrier layer on at least one surface of a shrink film. The layers are laminated in order of the shrink film, the recording layer, the anchor coat layer, and the barrier layer. An arithmetic mean roughness (Ra) of a surface of the anchor coat layer is not larger than 0.80 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a shrink label. More specifically, the present invention relates to a shrink label that has a printed layer that displays a design and the like and that exhibits excellent oxygen barrier properties.

  At present, plastic containers such as PET bottles are widely used as beverage containers for tea and soft drinks from the viewpoint of light weight and recyclability. In many cases, these containers are coated with a resin composition such as an ink or a coating agent for the purpose of displaying the contents and imparting various functions such as decorativeness, scratch resistance, and slipperiness. Labels made of plastic film (such as shrink labels) are attached. As such a shrink label, those based on a film made of polyester resin, polyolefin resin, polystyrene resin or the like are generally used.

  However, since these plastic containers and labels are inferior in gas barrier properties, there is a problem that quality deterioration is likely to occur due to oxidation of the contents and the quality assurance period is shortened, and improvement of gas barrier properties has been demanded.

  As a technique for solving this problem, for example, a technique of coating a gas barrier thin layer such as DLC (diamond-like carbon) or silica on the outer surface of a plastic container is known (see Patent Document 1). However, as described above, when the coating layer is applied to the container, there are problems that the manufacturing process becomes complicated and the productivity is lowered, and expensive equipment investment is required and the cost is increased.

  In addition, as a method for solving such problems in terms of cost and productivity, a barrier coat layer containing an inorganic layered mineral is provided on a base film, and if necessary, a barrier coat layer (barrier layer) is further provided. ) A shrink label packaging material having a printed layer thereon is known (see Patent Document 2). However, when these barrier layers are used as shrink labels, they must be attached to the container with the barrier layer side inside (container side) to protect the barrier layer. When the printed layer is provided on the container side (that is, the container side from the barrier layer), after the shrinkage, the transparency of the barrier layer is lowered, and when the design is viewed through the barrier layer, the design is clouded or whitened. It was.

  That is, the present condition is that the container which satisfy | fills low cost, productivity, decorativeness etc., and has the outstanding gas barrier property is not yet obtained.

JP 2002-68308 A JP 2005-88964 A

  The inventors of the present invention have studied a shrink label having the above-described barrier coat layer and print layer. When the layer configuration is such that a barrier coat layer (hereinafter simply referred to as a barrier layer) is provided on the print layer. Since the printed layer is outside the barrier layer when attached to the container (without looking through the design through the barrier layer), the above-mentioned decorative problem can be improved, but the gas barrier property is reduced after shrink processing. It has been found that there is a new problem of significant reduction.

  That is, an object of the present invention is to provide an excellent shrink label having both decorativeness and gas barrier properties. Another object of the present invention is to provide a labeled container excellent in all of productivity, cost, decorativeness, and gas barrier property, which is provided with the shrink label.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have a specific resin composition and layer structure, and further make the surface roughness of the anchor coat layer a specific range, thereby providing a decorative property by the printed layer. Found that a shrink label having a good and excellent gas barrier property can be obtained, and the present invention has been completed.

  That is, the present invention is a shrink label having at least one printed layer containing a pigment, an anchor coat layer, and a barrier layer on at least one side of the shrink film, each layer being a shrink film / print layer / anchor coat layer / barrier. A shrink label is provided in which the layers are laminated in the order of layers, and the arithmetic average roughness (Ra) of the surface of the anchor coat layer is 0.80 μm or less.

  Furthermore, the present invention provides the shrink label, wherein the print layer includes a urethane resin or an acrylic resin, and the anchor coat layer includes a urethane acrylic resin.

  Furthermore, this invention provides the said shrink label which has the protective layer which further contains the urethane acrylic resin on the surface of the said barrier layer.

  Further, according to the present invention, the printed layer includes at least one white printed layer, and the white printed layer contains 20 to 60% by weight of titanium oxide with respect to the total solid content of the ink. A shrink label as defined above is provided.

  Furthermore, the present invention provides the shrink label, wherein the barrier layer contains an ethylene-vinyl alcohol copolymer and an inorganic layered compound.

  Furthermore, this invention provides the container with a label formed by mounting | wearing said shrink label by making the surface of the side in which the barrier layer was provided with respect to the shrink film into the container side.

  The shrink label of the present invention does not deteriorate the decorative property such as “cloudy” even after the shrink processing, and a container having a beautiful finish can be obtained. In addition, even after shrink processing, excellent gas barrier properties are maintained, so that the quality of the contents of the container equipped with the label is prevented from being deteriorated, and the quality assurance period can be extended. Further, the label container equipped with the label is excellent in productivity and cost because it is not necessary to perform special barrier processing. Therefore, it is particularly useful as a label used for PET bottles and the like.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing an example of the shrink label of the present invention. The shrink label 1 shown in FIG. 1 is provided with a printed layer 3, an anchor coat layer 4, a barrier layer 5, and a protective layer 6 in this order on at least one side of a shrink film 2.

  The shrink label of the present invention has at least one shrink film, a print layer, an anchor coat layer, and a barrier layer (barrier coat layer). Moreover, it is necessary to have the structure where said each layer is laminated | stacked in order of a shrink film / printing layer / anchor coat layer / barrier layer on the at least single side | surface of a shrink film. However, the printed layer does not need to be provided on the entire surface of the label, and may partially include a portion having a laminated structure such as a shrink film / anchor coat layer / barrier layer and a shrink film / barrier layer. In each of the above layers, the anchor coat layer and the barrier layer are directly laminated without interposing other layers. Other layers may be directly laminated without interposing other layers, but may be laminated via other layers between the respective layers. Each of the above layers may be a single layer or a layer composed of two or more layers.

  As long as the shrink label of this invention has the said structure, it may have other layers other than the above, such as a protective layer, an adhesive layer, an ultraviolet absorption layer, an overlaminate layer, for example, and has a protective layer among them. It is preferable. Moreover, you may provide the coating layer which improves the adhesiveness of a printing layer and a film on an inner surface of a shrink film.

  Specific examples of the laminated structure of the shrink label of the present invention include, for example, shrink film / print layer / anchor coat layer / barrier layer, shrink film / print layer / anchor coat layer / barrier layer / protective layer, shrink film / coat layer. / Print layer / anchor coat layer / barrier layer / protective layer, etc. From the viewpoint of improving scratch resistance and water vapor barrier property, shrink film / print layer / anchor coat layer / barrier layer / protective layer, shrink film / A laminated structure of coat layer / print layer / anchor coat layer / barrier layer / protective layer is particularly preferred. In addition, the shrink label of this invention is mounted | worn with a container so that a shrink film may become an outer side (opposite side with a container), and a barrier layer may become an inner side (container side) among the said laminated structures.

  The shrink film used for the shrink label of the present invention is a layer that becomes a base material of the label, and is a layer that bears strength characteristics, shrinkage characteristics, and the like. The resin used for the shrink film can be appropriately selected according to the required physical properties and cost, and is not particularly limited. For example, polyester, polyolefin, polystyrene, polyvinyl chloride, polyamide, aramid, polyimide, polyphenylene Resins such as sulfide and acrylic can be used. Among these, a polyester film, a polyolefin film, a polystyrene film, and a polyvinyl chloride film are preferable, and a polyester film is most preferable because it can cover the entire surface of the container because of high shrinkage. As the polyester, polyethylene terephthalate (PET), poly (ethylene-2,6-naphthalenedicarboxylate) (PEN) or the like can be used, and among them, polyethylene terephthalate (PET) is preferable. In addition, as the polyolefin, polypropylene, polyethylene, cyclic olefin, or the like can be used.

  The shrink film of the present invention may be a single layer film, or may be a laminated film in which a plurality of film layers are laminated according to required physical properties, applications, and the like. In the case of a laminated film, film layers made of different resins may be laminated. For example, a three-layer laminated film composed of a center layer and a surface layer portion, a film wherein the center layer is composed of a polyolefin resin and the surface layer is composed of a polyester resin is preferable. When a polyolefin resin is used for the center layer, the water vapor barrier property is improved.

  The shrink film of the present invention is preferably a uniaxially, biaxially or multiaxially oriented film from the viewpoint of exhibiting shrink characteristics. When the shrink film is a laminated film, it is preferable that at least one film layer in the laminated film is oriented. When all the film layers are non-oriented, sufficient shrink characteristics may not be exhibited. As the shrink film, in particular, a uniaxial or biaxially oriented film is often used, and among them, a film that is strongly oriented in the film width direction (direction that becomes the label circumferential direction) (substantially uniaxially stretched in the width direction). Generally used).

  The shrink film of the present invention can be produced by a conventional method such as melt film formation or solution film formation. It is also possible to use a commercially available shrink film. The surface of the shrink film may be subjected to conventional surface treatment such as corona discharge treatment or primer treatment, if necessary. When a shrink film having a laminated structure is produced, a conventional method such as a co-extrusion method or a dry lamination method can be used as a lamination method. As a method for orienting the shrink film, biaxial stretching in the longitudinal direction (longitudinal direction; MD direction) and width direction (transverse direction; TD direction), or uniaxial stretching in the longitudinal direction or the width direction is used. As the stretching method, any of a roll method, a tenter method, and a tube method may be used. The stretching treatment is performed at a temperature of about 70 to 100 ° C., if necessary, for example, 1.01 to 1.5 times, preferably about 1.05 to 1.3 times in the longitudinal direction, and then 3 in the width direction. It is often carried out by stretching about 6 times, preferably about 4 to 5.5 times.

  The thermal shrinkage rate (90 ° C., 10 seconds) of the shrink film of the present invention is not particularly limited, but from the viewpoint of shrink workability and the like, particularly when the shrink label of the present invention is a cylindrical shrink label, the longitudinal direction is -3 to 15% and the width direction is preferably 20 to 90%. In the case of a wound shrink label, the longitudinal direction is preferably 20 to 80% and the width direction is preferably -3 to 20%.

  The transparency (haze value (%): JIS K 7105) of the shrink film of the present invention is preferably less than 10, more preferably less than 5.0, and still more preferably less than 2.0. When the haze value is 10 or more, when printing is shown through the shrink film, the printing may become cloudy and the decorativeness may be deteriorated.

  Although the thickness of the shrink film of this invention is not specifically limited, 10-100 micrometers is preferable, More preferably, it is 20-80 micrometers, More preferably, it is 30-60 micrometers. In addition, when the shrink film of the present invention is a three-layer laminated film composed of the above-described center layer and surface layer portion, the thickness ratio of the center layer to the surface layer portion (surface layer / center layer / surface layer) is 1/2 / 1-1 / 5/1 is preferable.

  Commercially available products can be used as the shrink film of the present invention, and examples thereof include “Hispet” manufactured by Mitsubishi Plastics, “Space Clean” (PET film) manufactured by Toyobo.

  The printed layer in the shrink label of the present invention is a layer for displaying a product name, an illustration, a design, handling precautions, and the like, and includes a binder resin and a pigment. The printing layer of the present invention is formed by applying and drying a printing ink containing a binder resin, a pigment, and, if necessary, a solvent as constituent components. The printing ink of the present invention is preferably an evaporation drying type ink (such as a solvent type ink).

  As the binder resin, a known and commonly used binder resin usually used in gravure ink can be used, and is not particularly limited, and examples thereof include urethane resins, acrylic resins, and cellulose resins. Of these, urethane resins and acrylic resins are preferably exemplified.

  The urethane-based resin is a resin obtained by reacting a polyisocyanate compound and a polyol compound, and is not particularly limited. However, a conventional or known polyurethane resin having adhesion (adhesion) to a plastic film is used. preferable.

  As the polyisocyanate compound, one or a mixture of two or more known diisocyanates of aromatic, aliphatic and alicyclic groups can be used. Specific examples of diisocyanates include tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 1,5-naphthalene diisocyanate, and isophorone diisocyanate. If necessary, trifunctional or higher functional polyisocyanates and polyisocyanate adducts can be mixed with the diisocyanate.

  Examples of the polyol compound include ethylene glycol, diethylene glycol, 1,3-propanediol, propylene glycol, butanediol (1,3-butanediol, 1,4-butanediol, etc.), 1,6-hexanediol, and cyclohexanedimethanol. Low molecular weight glycols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene glycol-polycaprolactone copolymer and other polyether diols; propylene glycol, butanediol, hexanediol and other diols and adipic acid, Polyester diol obtained from dibasic acids such as sebacic acid, azelaic acid, isophthalic acid, terephthalic acid, fumaric acid; polycaprolactone polyol, polyvale Lactone polyol, a known diols, lactone diols such as lactone block copolymer polyols can be used. Moreover, said diols and a trifunctional or more than trifunctional polyol compound can also be mixed and used as needed.

Examples of the monomer component constituting the acrylic resin include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and butyl (meth) acrylate. , Isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ( (Meth) acrylic acid alkyl esters such as isononyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate [preferably (meth) acrylic acid C _1-12 alkyl ester, etc.]; (meth) acrylic acid Carboxyl group-containing polymerizable unsaturated compounds such as crotonic acid, itaconic acid, fumaric acid, maleic acid, etc. Its anhydride: 2-hydroxymethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, diethylene glycol mono (meth) acrylate, dipropylene glycol Examples thereof include hydroxyl group-containing (meth) acrylic acid esters such as mono (meth) acrylate [preferably (meth) acrylic acid hydroxy C _1-8 alkyl ester and the like].

  In addition to the above, if necessary, (meth) acrylic acid cycloalkyl esters such as cyclohexyl (meth) acrylate; N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-dimethyl (Meth) acrylic acid amide derivatives such as (meth) acrylamide and N, N-diethyl (meth) acrylamide; dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, dimethylamino (Meth) acrylic acid dialkylaminoalkyl esters such as propyl (meth) acrylate and dipropylaminopropyl (meth) acrylate; styrene compounds such as styrene, vinyltoluene and α-methylstyrene; vinyl acetate, Vinyl esters such as vinyl pionate; Vinyl halides such as vinyl chloride; Vinyl ethers such as methyl vinyl ether; Cyano group-containing vinyl compounds such as (meth) acrylonitrile; Polymerizability of olefins and dienes such as ethylene and propylene Unsaturated compounds can also be used as monomer components.

  Examples of the cellulose resin that is the binder resin include esterified cellulose resins such as nitrocellulose (nitrified cotton) resin, cellulose acetate butyrate resin, cellulose acetate, and cellulose acetate propionate.

  As the pigment used in the printing ink of the present invention, organic and inorganic coloring pigments can be used, white pigments such as titanium oxide (titanium dioxide), indigo pigments such as copper phthalocyanine blue, and red pigments such as bengara (iron oxide). Carbon black, aluminum flakes, mica (mica), etc. can be selected and used according to the application. In addition, extender pigments such as alumina, calcium carbonate, barium sulfate, silica, and acrylic beads can also be used as pigments for the purpose of adjusting gloss. Among these, when the printing layer of the present invention is a white printing layer using a white printing ink, titanium oxide is preferably used as the pigment. As the titanium oxide, any of rutile type (tetragonal high temperature type), anatase type (tetragonal low temperature type), and brookite type (orthorhombic type) may be used. For example, titanium oxide particles manufactured by Ishihara Sangyo Co., Ltd. The “Taipaque Series” and the Titanium Co., Ltd. titanium oxide “JR Series” are available.

  The average particle size of the pigment used in the printing ink of the present invention (in the case where an aggregate is formed, the particle size of the aggregate, so-called secondary particle size) varies depending on the type of pigment and the purpose of printing, and in particular. Although not limited, in the case of titanium oxide particles, for example, 0.01 to 1 μm is preferable, and 0.1 to 0.5 μm is more preferable. When the average particle size is less than the above range, the dispersibility is deteriorated. When the average particle size is exceeded, the surface of the printing layer becomes rough, and the gas barrier property after shrink processing may be deteriorated or the appearance may be deteriorated. The pigment content can be arbitrarily designed depending on the type of pigment, the target color density, etc., but is preferably about 0.1 to 70% by weight based on the total solid content of the printing ink. Among these, the content of titanium oxide is preferably 20 to 60% by weight, more preferably 30 to 55% by weight from the viewpoints of concealability, coarse protrusion formation suppression, and gas barrier property improvement.

  The solvent used in the printing ink of the present invention plays a role of improving coating processability and compatibility and dispersibility of each component in the ink, and is volatilized and removed in a drying step after coating. Examples of such solvents include those usually used in organic solvents such as toluene, xylene, methyl ethyl ketone, ethyl acetate, propyl acetate, methyl alcohol, ethyl alcohol, isopropyl alcohol, gravure such as water, and flexographic printing inks. Can be used.

  In the printing ink of the present invention, if necessary, for the purpose of imparting other functions, resin components other than the binder resin, dispersants, antioxidants, antistatic agents, fragrances, deodorants, stabilizers, color separations. You may add inhibitor etc. to such an extent that the effect of this invention is not impaired. In the present invention, in order to control the surface roughness of the label surface within an appropriate range, it is preferable to reduce the content of the lubricant component in the printing ink as much as possible. The addition amount is preferably less than 5% by weight, more preferably less than 3% by weight, and even more preferably no lubricant is added to the total solid content of the printing ink. If a lubricant is added in an amount of 5% by weight or more, the printed layer surface becomes too rough, and the gas barrier property after shrink processing may be lowered. The above-mentioned lubricant means, for example, polyolefin waxes such as polyethylene wax, various waxes such as fatty acid amide, fatty acid ester, paraffin wax, polytetrafluoroethylene (PTFE) wax, carnauba wax and the like.

  The viscosity (23 ± 2 ° C.) of the printing ink of the present invention is not particularly limited. For example, when it is applied by gravure printing, it is preferably 10 to 2000 mPa · s, more preferably 20 to 1000 mPa · s. is there. When the viscosity exceeds 2000 mPa · s, the gravure printability may be lowered, and “decrease” or the like may occur, and the decorating property may be lowered. On the other hand, when the viscosity is less than 10 mPa · s, the storage stability may be deteriorated, for example, the pigment or the additive may easily settle. The viscosity of the resin composition can be controlled by the blending ratio of the binder resin, the pigment and the solvent, the thickener, the thickener and the like. In the present specification, “viscosity” means that, unless otherwise specified, a B-type viscometer (single cylindrical rotational viscometer) is used and the condition is JIS 2 It means a value measured according to Z8803.

  Commercially available products can be used as the printing ink of the present invention, and examples include “Etna” manufactured by Sakata Inx Co., Ltd., “NT-Hilamic” manufactured by Dainichi Seika Kogyo Co., Ltd., and the like.

  The printing layer of the present invention can be formed by coating and drying the printing ink. As a printing ink coating method, a gravure printing method or a flexographic printing method is preferable, and a gravure printing method is particularly preferable, from the viewpoints of cost, productivity, printing decoration, and the like.

  The printing layer of the present invention may be a single layer, but may be a printing layer having a laminated structure in which a plurality of printing layers are overprinted. Above all, in order to make the color design clearer, the printed layer has a layered structure (a structure in which the white printed layer is the inside when mounted on a container) provided with a white printed layer made of white printing ink on the color designed printed layer. Is generally used. The present invention is particularly useful in the case of a laminated structure in which an anchor coat layer is provided on a white printed layer and then a barrier layer is provided. That is, when the printed layer is a multilayer laminated structure, the white printed layer is a barrier. It is preferable to be provided on the layer side. For example, it is preferable to have a layer structure of shrink film / color design print layer / white print layer / anchor coat layer / barrier layer.

  The thickness of the printing layer (single layer) of the present invention is not particularly limited, but is preferably 0.1 to 15 μm, more preferably 0.5 to 10 μm. If the thickness is less than 0.1 μm, it may be difficult to provide a uniform printing layer, and partial “blur” may occur, resulting in a loss of decorativeness or printing as designed. May be difficult. In addition, when the thickness exceeds 15 μm, a large amount of ink is consumed, which increases the cost, makes it difficult to apply uniformly, and makes the printing layer brittle and easy to peel off. To do. Especially, in the case of a white ink layer, the thickness is preferably 3 to 10 μm from the viewpoint of concealment.

  The arithmetic average roughness (Ra) (hereinafter also simply referred to as surface roughness) of the surface of the printing layer of the present invention is preferably 0.8 to 5.0 μm. When the surface roughness of the printing layer surface exceeds 5.0 μm, it may be difficult to control the label surface roughness within the range defined in the present invention.

  The anchor coat layer of the present invention is a layer that plays a role of smoothing irregularities on the surface of the print layer and improving the adhesion between the print layer and the barrier layer. The anchor coat layer of the present invention is not particularly limited, but preferably contains a urethane acrylic resin as a resin component. The urethane acrylic resin is a copolymer having a urethane component and a (meth) acrylic component in the molecule. Examples of the urethane component and (meth) acrylic component include those described above as the urethane resin and acrylic resin, respectively.

  The anchor coat layer of the present invention may be a mixture of an anchor coat main agent and an anchor coat curing agent, and is formed by applying and drying on the printed layer. As a solvent, the solvent similar to the said printing layer is mentioned, for example. A preferable coating method is the same as that for the printing layer, and a gravure printing method is particularly preferable.

  The viscosity of the anchor coating agent (Zahn cup # 3, 23 ± 2 ° C.) is preferably 15 to 25 s, more preferably 16 to 20 s. When the viscosity exceeds 25 s, uniform coating becomes difficult and the anchor coat layer surface may become rough. If the viscosity is less than 15 s, an anchor coat layer having a sufficient thickness cannot be formed, and the unevenness of the printed layer may not be smoothed. In addition, the said viscosity means the viscosity just before coating after 2 liquid mixing.

  Commercially available products can be used as the anchor coat agent as described above, and examples thereof include “anchor coat main agent (N-1) / anchor coat curing agent (R-1)” manufactured by Sakata Inx Corporation. .

  The thickness of the anchor coat layer of the present invention is preferably from 0.1 to 10.0 μm, more preferably from 1.0 to 5.0 μm. When the thickness is less than 0.1 μm, the unevenness on the surface of the printing layer cannot be sufficiently smoothed, the surface of the anchor coat layer becomes rough, and the gas barrier property after shrink processing may be lowered. In addition, when the thickness exceeds 10.0 μm, a large amount of anchor coating agent is consumed, which may increase the cost or make it difficult to apply uniformly.

  The arithmetic average roughness (Ra) of the anchor coat layer surface of the present invention is 0.80 μm or less. When the surface roughness of the anchor coat layer surface exceeds 0.80 μm, when a barrier layer is provided on the anchor coat layer, it is difficult to form a barrier layer having a uniform thickness, and the adhesion of the barrier layer is reduced. Due to dimensional changes during shrink processing, relatively large barrier layer cracks are likely to occur, and gas barrier properties are reduced. Moreover, when an inorganic layered compound is contained in a barrier layer, since these do not arrange in a uniform direction, when shrink processing is performed, a clearance gap will be formed between inorganic layered compounds, and gas barrier property will fall.

  The barrier layer of the present invention is a layer having gas barrier properties (including water vapor barrier properties) that suppress the permeation of at least one gas selected from oxygen, water vapor, carbon dioxide gas, nitrogen and the like. Among these, a layer having an oxygen barrier property is particularly preferable. Examples of the barrier layer having an oxygen barrier property include a layer formed by coating a barrier agent mainly composed of a resin, an inorganic thin film layer such as DLC, alumina, and silica. Each layer can be formed continuously. A barrier layer formed by coating is more preferable from the viewpoint of high productivity because there is no blocking problem, and further excellent cost and shrink processing followability.

  When the barrier layer of the present invention is formed by coating with a barrier agent, as the barrier agent (coating agent), a composition comprising a resin component, an inorganic layered compound and a solvent as essential components is preferably used. The coating is preferably performed by gravure or flexographic printing.

  Although it does not specifically limit as a resin component used for the barrier agent of this invention, Polyvinyl alcohol, an ethylene- vinyl alcohol type copolymer, those modified substances, etc. are used preferably. Among these, an ethylene-vinyl alcohol copolymer is particularly preferable.

  The ethylene-vinyl alcohol copolymer is a compound obtained by saponifying an ethylene-vinyl acetate copolymer (a copolymer having ethylene and vinyl acetate as essential monomer components). The ethylene component content of the ethylene-vinyl alcohol copolymer is preferably 20 to 60% by weight with respect to the total amount of the monomer components from the viewpoint of water resistance. Further, the saponification degree of the vinyl acetate component is preferably 95 mol% or more from the viewpoint of gas barrier properties.

  Examples of the inorganic layered compound used in the barrier agent of the present invention include clay minerals such as kaolinite, dickite, nacrite, montmorillonite, synthetic fluorine mica, and graphite. Among these, montmorillonite is particularly preferable from the viewpoints of gas barrier properties, cost, workability, and the like.

  Although the solvent used for the barrier agent of the present invention is not particularly limited, water, alcohols such as ethyl alcohol, propyl alcohol, isopropyl alcohol, isobutyl alcohol, and mixed solvents thereof are preferably used. Especially, the mixed solvent which consists of water: 50-95 weight part and alcohol: 5-50 weight part is preferable from a soluble viewpoint.

  Furthermore, a coupling agent such as a titanium coupling agent or a silane coupling agent may be added to the barrier agent of the present invention for the purpose of improving water resistance.

  From the viewpoint of gas barrier properties, the thickness of the barrier layer formed by the coating is preferably 0.2 to 10.0 μm, more preferably 1.0 to 5.0 μm.

  As said barrier agent, it is also possible to use a commercial item, For example, Sakata Inx Co., Ltd. product "barrier coating agent (F-2D)" etc. are mentioned.

  When an inorganic thin film is used as the barrier layer of the present invention, the barrier layer is formed by a physical vapor synthesis method (PVD) such as vacuum deposition, sputtering method, ion plating method, reduced pressure chemical vapor synthesis method (CVD), It can be formed by a known and common technique such as plasma CVD.

  A protective layer is preferably provided on the barrier layer of the present invention as necessary. The protective layer is a layer that plays a role of protecting the barrier layer from moisture when imparting scratch resistance and protecting the barrier layer from process scraping or when an ethylene-vinyl alcohol copolymer is used. As the protective layer, known and commonly used varnish for shrink film can be used, and examples thereof include a coating layer formed by an evaporative drying type coating agent made of acrylic resin or urethane acrylic resin.

  As for the thickness of the said protective layer, 0.1-10 micrometers is preferable, More preferably, it is 1-5 micrometers.

  As the coating agent (top coat agent) for forming such a protective layer, a commercially available product can be used, and examples thereof include “Top Coat 667” manufactured by Sakata Inx Corporation.

  The arithmetic average roughness (Ra) of the label surface on the side provided with the barrier layer of the shrink label of the present invention is preferably 0.10 to 0.80 μm. The “label surface on the side on which the barrier layer is provided” refers to the label surface on the “side on which the laminated structure of the printing layer / anchor coat layer / barrier layer is provided” with respect to the shrink film. When the shrink label of the present invention is attached to a container, the label is usually attached with the surface inside (that is, the container side).

  In the shrink label of the present invention, the printing layer and the barrier layer are formed in the order of the shrink film, the printing layer, and the barrier layer. For this reason, when it sees from the shrink film side which is an outer side of a label, printing becomes clear after shrinkage processing and a decorating property improves. When formed in the order of a shrink film, a barrier layer, and a printing layer, the barrier layer is generally inferior in transparency, and in particular, after shrinkage processing, the decorativeness is deteriorated such that printing appears cloudy.

  On the other hand, in general, in a shrink label in which a barrier layer is provided on the surface layer side of the printed layer, there has been a problem that the barrier property (for example, oxygen permeability) is drastically lowered by shrink processing. This is because the printed layer contains a pigment and the surface has a certain degree of roughness. In this case, since the barrier layer is provided on the rough surface, it is difficult to form a barrier layer having a uniform thickness. It is presumed that the adhesiveness is lowered and a relatively large barrier layer is easily cracked due to a dimensional change during shrink processing. In addition, when the inorganic layered compound is included in the barrier layer, they are not arranged in a uniform direction, so that it is assumed that a gap is formed between the inorganic layered compounds when shrink processing is performed.

  In the present invention, by providing a specific anchor coat layer between the print layer and the barrier layer, irregularities on the surface of the print layer are filled, and the surface on which the barrier layer is formed is smoothed to a specific surface roughness. Thereby, a barrier layer having a uniform thickness can be formed, and the adhesion of the barrier layer is dramatically improved.In addition, when an inorganic layered compound is used for the barrier layer, the arrangement of the compounds becomes uniform. Achieved significant reduction in barrier properties due to shrink processing. This makes it possible to achieve both high decorativeness and barrier properties of the printed layer.

When the shrink label of the present invention is an oxygen barrier label, the oxygen permeability (23 ° C., 60% RH, JIS K7126B (MOCON method)) of the shrink label (at 50% shrinkage) is 7.5 (cc / m ² · atm · day) or less, more preferably 5.0 (cc / m ² · atm · day) or less, and even more preferably 3.0 (cc / m ² · atm · day) or less. When the oxygen permeability exceeds 7.5 (cc / m ² · atm · day), the effect of suppressing the quality deterioration of the contents due to oxidation is not sufficient.

  The shrinkage rate (90 ° C., 10 seconds) in the main orientation direction (main stretching direction) of the shrink label (before shrink processing) of the present invention is preferably 10% or more (for example, 10 to 90%), more preferably. 20-90%. When the thermal shrinkage rate is less than 10%, the shrinkage is not sufficient in the step of closely attaching the shrink label to the container with heat, so that the adhesion with the container is lowered and the gas barrier effect may be lowered. In addition, the said main orientation direction is the direction which mainly performed the extending | stretching process, and is the said extending | stretching direction (generally width direction) in the case of a uniaxially stretched film.

  The thermal shrinkage rate (90 ° C., 10 seconds) in the direction perpendicular to the main orientation direction of the shrink label (before shrink processing) of the present invention is −3 to 20 from the viewpoints of shrink label mounting properties, workability, and the like. % Is preferable, and more preferably -1 to 15%. The direction orthogonal to the main orientation direction is generally the longitudinal direction (line direction of the film production line).

  The storage stability of the shrink label of the present invention (natural shrinkage rate: shrinkage rate when (40 ° C., 7 days) has elapsed) is preferably 3.0% or less, more preferably 1.5% or less. . If the film has a natural shrinkage ratio of more than 3.0%, after shrink labels are produced and stored until processing, large deformation (shrinkage) occurs, making subsequent processing difficult and increasing productivity. It may decrease, or printing may be distorted and cause complaints.

  Although the thickness of the shrink label of this invention is not specifically limited, 10-100 micrometers is preferable, More preferably, it is 30-70 micrometers.

  Although the form of the shrink label of this invention is not specifically limited, such as a cylindrical label and a winding label, A cylindrical shrink label (cylindrical shrink label) is preferable. The cylindrical shrink label is usually formed in a cylindrical shape so that the main orientation direction (width direction) of the shrink label is the circumferential direction and the surface on the barrier layer side is the inside.

  A labeled container can be obtained by mounting the shrink label of the present invention on a container and performing shrink processing. Containers used for the labeled containers include, for example, soft drink bottles such as PET bottles, milk bottles for home delivery, food containers such as seasonings, bottles for alcoholic beverages, pharmaceutical containers, detergents, sprays, and other chemical products. Such as containers. The material of the container is not particularly limited, but plastics such as PET, paper, and the like are preferable from the viewpoint of exhibiting the gas barrier properties of the present invention. The shape of the container is not particularly limited, but a cylindrical or square bottle type is preferable. Above all, in the case of a shape having neck portions at the upper and lower ends of the bottle, by applying a heat-sensitive adhesive to the portion corresponding to the neck portion of the label and attaching it to the container, it becomes a structure in which air does not enter from the gap between the upper and lower ends. Therefore, the gas barrier property is further improved. Blow-molded bottles are preferred because the side barrel is thin and inferior in barrier properties, so that the effect of the label of the present invention is sufficiently exhibited. In addition, the adherend of the shrink label of this invention is not restricted to the said container.

  Since the labeled container using the shrink label of the present invention is excellent in gas barrier properties, it has effects such as prevention of quality deterioration such as oxidation of contents, dissipation of flavor, and extension of the quality guarantee period. For this reason, it is preferably used for contents such as vitamins, tea, oil, medicine, wines such as wine, and dairy products.

  The shrink label of the present invention is produced by forming a printed layer, an anchor coat layer, a barrier layer, and, if necessary, a protective layer on at least one surface of the shrink film. Below, although an example of the manufacturing method of the shrink label of this invention and the labeled container using this label is demonstrated, the manufacturing method of this invention is not limited to this.

  As described above, the printing layer, anchor coat layer, barrier layer, and protective layer are formed on the shrink film by applying and drying printing ink, anchor coat agent, barrier agent, top coat agent and the like, respectively. Can be mentioned. As the coating method, a gravure printing method is particularly preferable from the viewpoints of cost, productivity, and printing decoration. The drying method may be natural drying, but a general heating device capable of in-line heating (hot air heater, oven such as an infrared oven, infrared heater, etc.) may be used. Among these, a hot air heater is particularly preferable from the viewpoint of safety. In addition, when forming a multilayer printed layer, such as in the case of multicolor printing, or when forming each of the above layers in a continuous process, the coating and drying process may be repeated.

  The long shrink label on which each of the above layers is formed is slit into a predetermined width and wound into a roll to obtain a roll of a long shrink label.

  Next, while rolling out the roll-like material, the shrink film is formed into a cylindrical shape so that the main orientation direction (width direction) of the shrink film is the circumferential direction of the label and the barrier layer is on the inner side. Specifically, after a long shrink label is formed in a cylindrical shape, a solvent or an adhesive such as tetrahydrofuran (THF) is formed on one side edge of the label in a strip shape in the longitudinal direction with a width of about 2 to 4 mm. (Solvent, etc.) is applied to the inner surface, and the coated portion of the solvent, etc. is superposed on the position of 5 to 10 mm from the other side edge portion and adhered to the outer surface (center seal), and a continuous cylindrical shrink label A long cylindrical shrink label is obtained. In addition, it is preferable that the part which coats said solvent etc. is not printed.

  In the case where a perforation for label excision is provided, a perforation having a predetermined length and pitch is formed in the longitudinal 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 appropriately selected after the printing process and before and after the cylindrical processing process.

  Furthermore, after cutting the long cylindrical shrink label obtained above, it is attached to a predetermined container, and the container is prepared by shrinking the label by heat treatment and closely contacting the container. Specifically, the long cylindrical shrink label is supplied to an automatic label mounting device (shrink labeler), cut to a required length, externally fitted into a container filled with the contents, and hot air at a predetermined temperature. A container with a label is obtained by passing through a tunnel or steam tunnel, or by heat-shrinking by radiant heat such as infrared rays and closely contacting the container. Examples of the heat treatment include treatment with 90 ° C. steam.

[Methods for measuring physical properties and methods for evaluating effects]

(1) Oxygen permeability (at 50% contraction)
From the shrink labels (film thickness 50 μm) obtained in Examples and Comparative Examples, strip-shaped sample pieces having a length of 30 cm and a width of 20 cm were cut out in the main orientation direction (label width direction). A length portion of 20 cm in the length direction (main alignment direction) of the sample piece was fixed using a fixing jig with an interval of 10 cm, and immersed in warm water at 80 ° C., and the label was contracted in the main alignment direction. After confirming that the 20 cm length portion was contracted to 10 cm, it was used for the test.
The oxygen permeability (unit: cc / m ² · atm · day) was measured in accordance with JIS K7126B in an atmosphere of 23 ° C. and 60% RH using “OX-TRAN 100 type” manufactured by Mocon.

(2) Arithmetic mean roughness (Ra)
In the manufacturing stage of the shrink label, the anchor coat layer surface was measured using “VK-8550” manufactured by Keyence Corporation in accordance with JIS B0601. The measurement conditions are as follows.
Measurement direction: width direction (label circumferential direction)
Measurement length: 0.1 mm
Environmental conditions: 23 ° C, 60% RH

(3) Thermal shrinkage (90 ° C., 10 seconds)
A square sample piece of 100 mm (main orientation direction: width direction) × 100 mm (perpendicular direction to main orientation direction: longitudinal direction) was produced from the shrink label.
The sample piece was heat-treated for 10 seconds (under no load) in warm water at 90 ° C., the dimensions (width direction) of the sample before and after the heat treatment were read, and the heat shrinkage rate was calculated by the following formula. The average value of the test number of 5 times was defined as the shrinkage rate.
Shrinkage rate (%) = (L ₀ −L ₁ ) / L ₀ × 100
L ₀ : Size of sample before heat treatment (main orientation direction)
L ₁ : Sample dimensions after heat treatment (same direction as L ₀ )
When the main orientation direction is unknown, for example, the direction of heat shrinkage can be measured by changing the direction every 10 °, and the direction with the largest shrinkage can be set as the main orientation direction.

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

Example 1
As the shrink film, a polyethylene terephthalate film (“HISHIPET LS21S” manufactured by Mitsubishi Plastics, Inc., thickness 40 μm) was used.

  One side of the shrink film was coated with urethane white ink (“Etona” manufactured by Sakata Inx Co., Ltd., 60% by weight of titanium oxide) using a gravure printing machine and a 175-line gravure plate, and a hot air oven at a temperature of 60 ° C. And dried to form a printed layer (white ink layer). The arithmetic average roughness (Ra) of the printed layer surface after drying was 1.5 μm.

  Next, on the surface of the printing layer, using a gravure printing machine (175-line gravure plate) in the same manner as the printing layer, an anchor coat main agent (“N-1” manufactured by Sakata Inx Co., Ltd.) and an anchor coat curing agent (Sakata Inx ( Co., Ltd. “R-1”: isocyanate compound) mixture (mixing ratio (weight ratio) 3/1, viscosity (Zahn cup # 3): 16 s) was applied, dried in a hot air oven at a temperature of 60 ° C., and urethane An anchor coat layer made of an acrylic resin was formed. The arithmetic average roughness (Ra) of the anchor coat layer surface after drying was 0.78 μm.

  Further, on the surface of the anchor coat layer, a gravure printing machine (175-line gravure plate) is used in the same manner as the print layer, and a barrier coat agent (“F-2D” manufactured by Sakata Inx Co., Ltd .: ethylene-vinyl alcohol-based copolymer) The mixture was applied and dried in a hot air oven at a temperature of 60 ° C. Further, the above barrier layer coating step was repeated again, and the barrier layer was overcoated to form a barrier layer.

  A topcoat agent (“Topcoat 667” manufactured by Sakata Inx Co., Ltd.) is applied to the surface of the barrier layer using a gravure printing machine (175 gravure plate) in the same manner as the printing layer, and a hot air oven at a temperature of 60 ° C. And dried to form a protective layer.

  In the above, the process speed of gravure printing was 100 m / min.

As described above, a shrink label having a laminated structure of shrink film / printing layer (white ink layer) / anchor coat layer / barrier layer (two layers) / protective layer was obtained.
As shown in Table 1, the obtained shrink label satisfied the surface roughness of the present invention, and had excellent oxygen barrier properties before shrink processing and after 50% shrinkage processing.

  Further, the long shrink label obtained above is rolled into a cylindrical shape so that the barrier layer side is on the inner side and the width direction of the film is the circumferential direction, and center-sealed with tetrahydrofuran (THF). A tubular shrink label was obtained. Finally, the above long cylindrical shrink label is supplied to an automatic label mounting device (STS-1936 manufactured by Fujistec Corp.) and cut into each label, while a container (500 ml heat-resistant square PET bottle manufactured by Toyo Seikan Co., Ltd.) And heated and shrunk in a steam tunnel with an atmospheric temperature of 90 ° C. to obtain a labeled container. The resulting labeled container had an excellent finish.

Example 2
As shown in Table 1, a shrink label was obtained in exactly the same manner as in Example 1 except that the number of gravure plates when the anchor coat layer was printed was changed to 150.
As shown in Table 1, the obtained shrink label satisfied the surface roughness of the present invention, and had excellent oxygen barrier properties before shrink processing and after 50% shrinkage processing.

Comparative Example 1
As shown in Table 1, a shrink film was produced in the same manner as in Example 1 except that no anchor coat layer was provided.
As shown in Table 1, the obtained shrink film did not satisfy the surface roughness of the present invention, and the oxygen barrier property before shrink processing was excellent, but the oxygen barrier property was remarkably reduced by shrink processing.

Comparative Example 2
As shown in Table 1, the shrink label was applied in exactly the same way as in Example 1 except that the number of gravure plates when printing the anchor coat layer was changed to 200 and the barrier layer was changed to one. Obtained.
As shown in Table 1, the obtained shrink film did not satisfy the surface roughness of the present invention, and the oxygen barrier property before shrink processing was excellent, but the oxygen barrier property was remarkably reduced by shrink processing.

Comparative Example 3
As shown in Table 1, except that the number of gravure plates when the anchor coat layer is printed is changed to 250, and the barrier layer is changed to one layer (the number of gravure plates when printing is 200). Produced a shrink label in exactly the same manner as in Example 1.

It is a schematic sectional drawing which shows an example of the shrink label of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shrink label 2 Shrink film 3 Print layer 4 Anchor coat layer 5 Barrier layer 6 Protective layer

Claims (6)

  A shrink label having at least one printed layer containing a pigment, an anchor coat layer, and a barrier layer on at least one side of the shrink film, each layer being laminated in the order of shrink film / print layer / anchor coat layer / barrier layer A shrink label characterized by having an arithmetic average roughness (Ra) of the anchor coat layer surface of 0.80 μm or less.   The shrink label according to claim 1, wherein the printing layer includes a urethane resin or an acrylic resin, and the anchor coat layer includes a urethane acrylic resin.   The shrink label according to claim 1 or 2, further comprising a protective layer containing a urethane acrylic resin on the surface of the barrier layer.   The said printing layer contains at least 1 layer of white printing layer, This white printing layer is comprised from the white printing ink which contains 20 to 60 weight% of titanium oxide with respect to the solid content whole quantity of an ink. The shrink label according to any one of items 1 to 3.   The shrink label according to any one of claims 1 to 4, wherein the barrier layer contains an ethylene-vinyl alcohol copolymer and an inorganic layered compound.   A labeled container formed by mounting the shrink label according to any one of claims 1 to 5 with the surface of the shrink film on the side on which the barrier layer is provided as the container side.

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