JP2017181612A - Plastic label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic label capable of stably obtaining a plastic label excellent in resistance against a chemical component.SOLUTION: A plastic label has a label base material containing a plastic film, a printing layer provided on at least one surface of the label base material, and a protective printing layer provided so as to cover the printing layer, where the protective printing layer contains at least a reactant of a urethane resin containing a structural unit derived from polyester polyol as a main component of a polyol component and an aromatic polyisocyanate compound.SELECTED DRAWING: Figure 1

Description

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

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

  The shrink label as described above is generally provided with a printing layer on one surface of a label base material, and the printing layer becomes the innermost layer when a cylindrical shrink label is formed (for example, Patent Document 1). .

JP-A-10-309771

  Thus, when the plastic label in which the printed layer constitutes the outermost layer is used as a label for a container for toiletries such as detergents and sprays, the contents of the container adhere to the label, thereby the printed layer of the label Sometimes dissolved. For this reason, there is a demand for a plastic label capable of obtaining a label having excellent resistance to chemical components (for example, resistance to acid, alkali, organic solvent, etc.) contained in the contents of the container.

  Accordingly, an object of the present invention is to provide a plastic label that can stably obtain a label having excellent resistance to chemical components.

  That is, the present invention includes a label base material including a plastic film, a printing layer provided on at least one surface of the label base material, and a protective printing layer provided so as to cover the printing layer. The plastic printing label is characterized in that the protective printing layer contains at least a reaction product of a urethane resin and an aromatic polyisocyanate compound containing a structural unit derived from polyester polyol as a main component of a polyol component.

  The proportion of the structural unit derived from the polyester polyol relative to the total weight of the structural unit derived from the polyol compound in the urethane resin is preferably 50% by weight or more.

  The plastic label preferably has the protective printing layer on the surface of the plastic label.

  The present invention also provides a cylindrical plastic label using the plastic label and having the protective printing layer on the innermost surface.

  The plastic label is preferably a shrink label using a heat-shrinkable film as the label base material.

  Since the plastic label of the present invention has the above-described configuration, it can stably obtain a label excellent in resistance to chemical components. Therefore, when using plastic as a label for a container for toiletries such as detergents and sprays, The label is stable and excellent in resistance to chemical components, and the printed layer of the label is hardly dissolved by the contents of the container.

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

  The plastic label of the present invention has at least a label substrate including a plastic film, a printing layer provided on at least one surface of the label substrate, and a protective printing layer provided so as to cover the printing layer. The protective printing layer is a layer containing at least a reaction product of a urethane resin containing a structural unit derived from polyester polyol as a main component of a polyol component and an aromatic polyisocyanate compound. In the present specification, the protective printing layer may be referred to as “the protective printing layer of the present invention”. Moreover, in this specification, the said printing layer which the protection printing layer of this invention covers may be called "printing layer (X)" in order to distinguish from the protection printing layer of this invention. The plastic label of the present invention may contain a layer (other layers) other than the label base material, the printed layer (X) and the protective printed layer of the present invention within a range not impairing the effects of the present invention. . The “urethane resin containing a structural unit derived from polyester polyol as a main component of the polyol component” may be referred to as “the urethane resin of the present invention”.

  FIG. 1 is a schematic view (partial sectional view) showing one embodiment of the plastic label of the present invention. The plastic label 1 of the present invention shown in FIG. 1 has a label substrate 2 including a plastic film, a printing layer (X) 3, and a protective printing layer 4 of the present invention. In the plastic label 1 of the present invention shown in FIG. 1, the printed layer (X) 3 is provided on one surface of the label substrate 2. The protective printing layer 4 of the present invention is provided so as to cover the printing layer (X) 3.

[Protective printing layer of the present invention]
The protective printing layer of the present invention (for example, the protective printing layer 4 of the present invention in FIG. 1) is an essential layer in the plastic label of the present invention, and is provided on at least one surface of the label substrate. The protective printing layer of the present invention contains at least a reaction product of a urethane resin containing a structural unit derived from a polyester polyol as a main component of a polyol component constituting the urethane resin, and an aromatic polyisocyanate compound. The protective printing layer of the present invention may contain an unreacted (unreacted with an aromatic polyisocyanate compound) urethane resin of the present invention or an unreacted aromatic polyisocyanate compound. That is, in the protective printing layer of the present invention, the urethane resin and aromatic polyisocyanate compound of the present invention need only partially react, and do not need to react all. In the plastic label of the present invention, since such a protective printing layer is provided so as to cover the printing layer (X), the printing layer (X) is protected from dissolution by chemical components. Excellent resistance to chemical components. In addition, as said reaction material, the compound which the urethane type resin of this invention and the aromatic polyisocyanate compound couple | bonded (or bridge | crosslinked) by the urethane bond is mentioned.

  The protective printing layer of the present invention may be a single layer or a multilayer. In the case of a multilayer, for example, a two-layer structure composed of the protective printing layer of the present invention containing a white pigment and the colorless and transparent protective printing layer of the present invention not containing a coloring material can be mentioned. Note that the term “transparent” means that the layer has transparency to the extent that an adjacent layer can be visually recognized through layers such as a label base material and a printed layer.

  The protective printing layer of the present invention is obtained by applying a composition containing the urethane resin of the present invention and an aromatic polyisocyanate compound to at least one surface of a label base material, and drying and solidifying the composition. Obtained by reaction with an aromatic polyisocyanate compound. In the protective printing layer of the present invention, when the reaction between the urethane resin of the present invention and the aromatic polyisocyanate compound is not sufficient, a plastic label having excellent resistance to chemical components can be obtained by further proceeding with the above reaction.

  Examples of the reaction include curing reactions such as active energy ray curing, thermal curing, and two-component reaction curing. When the reaction is two-component reaction curing, the reaction may proceed at room temperature or may not proceed at room temperature. When the above reaction is a two-component reaction curing that proceeds at room temperature, the reaction proceeds over time from when two components (for example, a liquid containing the urethane resin of the present invention and a liquid containing an aromatic polyisocyanate compound) are mixed. May be. When the reaction is a two-component reaction curing that does not proceed or hardly occurs at room temperature, the reaction may be promoted by irradiation with active energy rays or heating.

(Urethane resin of the present invention)
The urethane resin of the present invention contains a structural unit derived from a polyester polyol as a main component of a polyol component constituting the urethane resin. Specifically, the urethane resin of the present invention is a resin obtained by reacting a polyisocyanate compound and a polyol compound, and is a resin using a polyester polyol as a main component of the polyol compound. That is, the urethane-based resin of the present invention has a structural unit derived from a polyisocyanate compound and a structural unit derived from a polyol compound, and includes a structural unit derived from a polyester polyol as a main component derived from a polyol compound. . The said polyester polyol may use only 1 type and may use 2 or more types. In the present specification, the “main component” refers to the most material (component) among the materials (components) contained in the component. Therefore, the most abundant component in all the polyol compounds constituting the urethane resin of the present invention is a polyester polyol.

  Examples of the polyisocyanate compound include known diisocyanates such as aromatic diisocyanate, aliphatic diisocyanate, and alicyclic diisocyanate. Examples of the 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 used in combination with the diisocyanates. The said polyisocyanate compound may use only 1 type, and may use 2 or more types.

  The polyester polyol is a polyester compound having two or more hydroxyl groups in the molecule (in one molecule), and among them, a polyester diol having two hydroxyl groups in the molecule is preferable. Although the said polyester polyol is not specifically limited, It is preferable that it is a polymer comprised by using dicarboxylic acid and diol as an essential structural component. That is, the polyester polyol preferably has at least a structural unit derived from a dicarboxylic acid and a structural unit derived from a diol. Moreover, said diol and trifunctional or more than trifunctional polyol compounds (polyether polyol, polyester polyol, etc.) can also be mixed and used as needed.

  Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, 2,5-dimethylterephthalic acid, 5-t-butylisophthalic acid, 4,4′-biphenyldicarboxylic acid, 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-naphthalenedicarboxylic acid, 2,6-naphthalene Dicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 2,2,6,6-tetramethylbiphenyl-4,4′-dicarboxylic acid, 1,1,3-trimethyl-3-phenylindene-4,5-dicarboxylic acid 1,2-diphenoxyethane-4,4′-dicarboxylic acid, diphenyl ether dicarboxylic acid, 2,5-ant Aromatic dicarboxylic acids such as sendicarboxylic acid, 2,5-pyridinedicarboxylic acid, and substituted products thereof; oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic 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, 1,12-dodecanedioic acid, and Aliphatic dicarboxylic acids such as these substitutes; 1,4-decahydronaphthalenedicarboxylic acid, 1,5-decahydronaphthalenedicarboxylic acid, 2,6-decahydronaphthalenedicarboxylic acid, cis-1,4-cyclohexanedicarboxylic acid , Trans-1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedi Carboxylic acid, and alicyclic dicarboxylic acids such as substituted versions thereof and the like. Among these, from the viewpoint of suppressing discoloration (yellowing) of the protective printing layer of the present invention, aliphatic dicarboxylic acids and aromatic dicarboxylic acids are preferable, and adipic acid, terephthalic acid, and isophthalic acid are more preferable. Among these, from the viewpoint of maintaining the flexibility of the protective printing layer of the present invention, it is more preferable to use at least an aliphatic dicarboxylic acid. The said dicarboxylic acid may use only 1 type, and may use 2 or more types.

  Examples of the diol include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 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, 3-methyl-1,5-pentanediol, Aliphatic diols such as 1,10-decanediol, polyethylene glycol and polypropylene glycol; 1,2-cyclo Cycloaliphatic diols such as xanthanimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol; 2,2-bis ( Examples thereof include ethylene oxide adducts of bisphenol compounds such as 4-β-hydroxyethoxyphenyl) propane and bis (4-β-hydroxyethoxyphenyl) sulfone, and aromatic diols such as xylylene glycol. Among these, aliphatic diols and alicyclic diols are preferable, and 1,4-butanediol, 1,6-hexanediol, neopentyl glycol (NPG), 3-methyl-1,5-pentanediol, 1, 4-cyclohexanemethanol. The said diol may use only 1 type and may use 2 or more types.

  As said polyol compound, other polyol compounds, such as polyether polyol, polycarbonate polyol, polylactone polyol, polyolefin polyol, polyacryl polyol, polyhydric alcohol, may be used besides polyester polyol. Moreover, the said other polyol compound may use only 1 type, and may use 2 or more types.

  Although the ratio of the structural unit derived from the said polyester polyol with respect to the total weight (100 weight%) of the structural unit derived from a polyol compound will not be specifically limited if it is a main component of the structural unit derived from a polyol compound, 50 weight% The above is preferable (for example, 50 to 100% by weight), more preferably 70% by weight or more, still more preferably 90% by weight or more, and particularly preferably 95% by weight or more. There exists a tendency for the tolerance with respect to a chemical component to improve that the said ratio is 50 weight% or more.

  In addition to the dicarboxylic acid and the diol, the polyester polyol includes oxycarboxylic acids such as p-oxybenzoic acid and p-oxyethoxybenzoic acid; monocarboxylic acids such as benzoic acid and benzoylbenzoic acid; trimellitic acid, etc. A polyhydric carboxylic acid; a monohydric alcohol such as polyalkylene glycol monomethyl ether; a polyhydric alcohol such as glycerin, pentaerythritol, and trimethylolpropane; and a structural unit derived from a cyclic ester such as caprolactone.

  The hydroxyl value of the urethane-based resin of the present invention (that is, the urethane-based resin of the present invention that has not reacted with other components such as an aromatic polyisocyanate compound) in the protective printing layer of the present invention is not particularly limited. 0.1-50 mgKOH / g is preferable, more preferably 0.5-30 mgKOH / g, and still more preferably 1-20 mgKOH / g. If the hydroxyl value is 0.1 mg KOH / g or more, it is presumed that the reactivity with the aromatic polyisocyanate compound is improved, but there is a tendency to be more excellent in the resistance of chemical components. When the hydroxyl value is 50 mgKOH / g or less, excessive reaction of the protective printing layer is suppressed, and when the label substrate is deformed, the protective printing layer easily follows the deformation, and the plastic label of the present invention In the case of the shrink label, the followability of the protective printing layer to the heat shrinkage of the heat shrinkable film on the label base material is improved. In the present specification, the hydroxyl value can be measured by potentiometric titration in accordance with JIS K 0070. Moreover, when the protective printing layer of this invention contains 2 or more types of urethane type resin of this invention, the said hydroxyl value is a hydroxyl value of the urethane type resin of this invention of the total.

  The weight average molecular weight (Mw) of the urethane resin of the present invention (that is, the urethane resin of the present invention that has not reacted with other components such as an aromatic polyisocyanate compound) in the protective printing layer of the present invention is particularly limited. However, it is preferably 10,000 to 100,000, more preferably 15,000 to 90,000, still more preferably 20,000 to 80,000. When the weight average molecular weight is 10,000 or more, the adhesiveness and resistance to fringing of the protective printing layer are excellent. When the weight average molecular weight is 100,000 or less, the printability of the protective printing layer is good. In addition, in this specification, although a weight average molecular weight (Mw) is not specifically limited, For example, it can measure by standard polystyrene conversion by GPC. Moreover, when the protective printing layer of this invention contains 2 or more types of urethane type resin of this invention, the said weight average molecular weight is a weight average molecular weight of the total urethane type resin of this invention.

  The glass transition temperature (Tg) of the urethane resin of the present invention (that is, the urethane resin of the present invention that has not reacted with other components such as an aromatic polyisocyanate compound) in the protective printing layer of the present invention is particularly limited. Although it is not, -80-90 degreeC is preferable, More preferably, it is -70-80 degreeC, More preferably, it is -60-70 degreeC.

  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.

  The protective printing layer of the present invention may contain the urethane resin of the present invention alone or in combination of two or more.

(Aromatic polyisocyanate compound)
The aromatic polyisocyanate compound is an aromatic compound having two or more isocyanate groups. By using an aromatic polyisocyanate compound in combination with the urethane resin of the present invention, the hardness of the protective printing layer of the present invention is increased, or the adhesiveness of the protective printing layer of the present invention to the label substrate or the printing layer (X) When the printing layer (X) contains a resin having a functional group that reacts with an isocyanate group (for example, urethane resin), the aromatic polyisocyanate compound in the protective printing layer is added to the printing layer (X). It is presumed to be due to penetration and curing of the printed layer (X), but improves resistance to chemical components. Examples of the aromatic polyisocyanate compound include known aromatic diisocyanates, such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, 1 , 3-phenylene diisocyanate, 1,5-naphthalene diisocyanate and the like. Further, if necessary, trifunctional or higher functional aromatic polyisocyanates and polyisocyanate adducts may be mixed with the aromatic diisocyanates. As for the said aromatic polyisocyanate compound, only 1 type may be used and 2 or more types may be used.

  The protective printing layer of the present invention may contain components other than the urethane resin and aromatic polyisocyanate compound of the present invention and their reactants within a range not impairing the effects of the present invention. The component is not particularly limited, but a resin other than the urethane resin of the present invention (for example, an acrylic resin, a urethane resin other than the urethane resin of the present invention, a polyester resin, a polyamide resin, a cellulose resin, Vinyl chloride resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin, polyolefin resin (for example, polyethylene resin, polybutadiene resin, etc.), isocyanate resin, rosin resin, polyvinyl alcohol resin (PVA resin) Resin), imine resins, etc.), colorants (coloring materials) such as pigments and dyes, additives (for example, curing agents other than aromatic polyisocyanate compounds, lubricants, plasticizers, anti-settling agents, dispersants, stabilizers) , Cross-linking agent, antifoaming agent, filler, antioxidant, UV absorber, antistatic agent, anti-coloring agent, perfume, deodorant, -Flops, etc.) and the like. The said component may use only 1 type and may use 2 or more types.

  It does not specifically limit as said pigment, For example, the pigment used in a well-known printing layer can be used. Examples of the pigment include white pigments such as titanium oxide (titanium dioxide), indigo pigments such as copper phthalocyanine blue, red pigments such as condensed azo pigments, yellow pigments such as azo lake pigments, carbon black, aluminum flakes, mica (Mica) and other colored pigments can be selected and used according to the application. In addition to the above pigments, extender pigments such as alumina, calcium carbonate, barium sulfate, silica, and acrylic beads can also be used for the purpose of adjusting gloss.

  Although the sum total of content of the urethane type resin of this invention and an aromatic polyisocyanate compound is not specifically limited, For example, 8 weight% or more with respect to the total weight (100 weight%) of the protective printing layer of this invention (for example, 8 to 99% by weight) or 13 to 98% by weight, preferably 50 to 97% by weight, more preferably 60 to 95% by weight, and still more preferably 70 to 90% by weight.

  When the protective printing layer of the present invention contains a white pigment such as titanium oxide (for example, when the protective printing layer of the present invention is a back surface printing layer), the content of the urethane-based resin of the present invention and the aromatic polyisocyanate compound Although total is not specifically limited, 8-70 weight% is preferable with respect to the total weight (100 weight%) of the protective printing layer of this invention, More preferably, it is 13-65 weight%, More preferably, it is 15-60 weight% %.

  On the other hand, when the protective printing layer of the present invention is a colorless and transparent protective printing layer containing no color pigment, the total content of the urethane-based resin and the aromatic polyisocyanate compound of the present invention is not particularly limited. It is preferably 50 to 99% by weight, more preferably 60 to 97% by weight, still more preferably 70 to 95% by weight, based on the total weight (100% by weight) of the protective printing layer.

  Although content of an aromatic polyisocyanate compound is not specifically limited, 1-70 weight part is preferable with respect to the total weight (100 weight part) of the urethane type resin of this invention, More preferably, 5-50 weight part, More preferably, it is 10-40 weight part. The tolerance with respect to a chemical component improves more as the said content is 1 weight part or more. When the content is 70 parts by weight or less, the coating property of the composition for forming the protective printing layer of the present invention is improved, and the protective printing layer of the present invention is provided on the surface of the plastic label of the present invention. Improves the anti-blocking property.

  When the protective printing layer of the present invention contains a white pigment such as titanium oxide (for example, when the protective printing layer of the present invention is a back printing layer), the content of the white pigment is not particularly limited, but the protection of the present invention 5 to 89% by weight is preferable with respect to the total weight (100% by weight) of the printed layer, more preferably 20 to 85% by weight, and still more preferably 30 to 80% by weight.

  When the protective printing layer of the present invention is a layer on the surface of the plastic label of the present invention, the protective printing layer of the present invention preferably further contains a lubricant. The content of the lubricant in this case is not particularly limited, but is preferably 1 to 20% by weight with respect to the total weight (100% by weight) of the protective printing layer of the present invention.

  In this specification, the content of the urethane resin of the present invention includes the urethane resin of the present invention in addition to the urethane resin of the present invention itself (that is, the unreacted urethane resin of the present invention). The structural unit derived from the urethane-type resin of this invention in the reaction material with other components, such as an aromatic polyisocyanate compound, is also contained. Similarly, in addition to the aromatic polyisocyanate compound itself (that is, the unreacted aromatic polyisocyanate compound), the content of the aromatic polyisocyanate compound includes the aromatic polyisocyanate compound and the urethane resin of the present invention. A structural unit derived from an aromatic polyisocyanate compound in a reaction product with other components is also included. The same applies to the total weight of the urethane resin of the present invention.

  Further, in the present specification, the content of each component (for example, the urethane resin of the present invention, the aromatic polyisocyanate compound, the pigment, etc.) contained in each layer is 100% by weight of the total content in each layer. It can select suitably from the description range so that it may become the following.

  Although the thickness of the protective printing layer of this invention is not specifically limited, For example, 0.1-10 micrometers is preferable, More preferably, it is 0.3-5 micrometers. When the thickness is 0.1 μm or more, the printed layer (X) can be sufficiently protected, and thus is more excellent in resistance to chemical components. Moreover, it becomes easy to provide a protective printing layer uniformly. on the other hand. When the thickness is 10 μm or less, it is easy to prevent the protective printing layer from becoming brittle and easy to peel off. Moreover, consumption of the composition which forms a protective printing layer can be minimized, and cost can be held down. Furthermore, it becomes easier to apply uniformly.

[Print layer (X)]
The print layer (X) (for example, the print layer (X) 3 in FIG. 1) is not particularly limited, and examples thereof include known or commonly used print layers used in plastic labels. The print layer (X) includes, for example, design print layers (color print layers, etc.) such as product names, illustrations, handling precautions, etc. and design print layers, and back print layers formed in a single color such as white. And a primer printing layer provided to improve the adhesion between the film and the printing layer. Above all, the printed layer (X) preferably includes a design printed layer. This is because the design printing layer includes illustrations and handling precautions as described above, so that dissolution and disappearance due to chemical components should be particularly prevented and should be particularly protected by the protective printing layer of the present invention.

  Although the said printing layer (X) is not specifically limited, You may be provided only in the single side | surface side of the said label base material, and may be provided in the both surfaces side of the said label base material. Moreover, the said printing layer (X) may be provided in the whole surface of the surface of the said label base material, and may be provided in a part. Further, the print layer (X) is not particularly limited, but may be a single layer or a multilayer. Moreover, the said printing layer (X) can be provided by the well-known thru | or usual printing method. More specifically, the printing layer (X) is preferably provided by a known or known printing method such as gravure printing, flexographic printing, screen printing, or digital printing.

  Although the kind of printing layer which comprises the said printing layer (X) is not specifically limited, A solvent drying type printing layer is preferable.

  The printing layer constituting the printing layer (X) preferably contains a binder resin as an essential component. Further, it preferably contains a colorant (coloring material) such as a pigment or a dye. Examples of the pigment include pigments exemplified and described as pigments that may be contained in the protective printing layer of the present invention. Each of the above binder resins may be used alone or in combination of two or more.

  The print layer (X) is preferably a design print layer, and particularly preferably a design print layer configured by combining two or more print layers having different colorants. In this case, the printing layers in the respective design printing layers may be provided in overlapping regions or may be provided in separate regions that do not overlap. Moreover, it is preferable that the design printing layer is formed of a plurality of printing layers having different color pigments so as to have a desired design.

  The binder resin is not particularly limited, and a known or conventional printing layer or binder resin for printing ink can be used. Although the said binder resin is not specifically limited, it plays the role as the main resin component which forms the said printing layer (X). Examples of the binder resin include acrylic resins, urethane resins, polyester resins, polyamide resins, cellulose resins, vinyl chloride resins, vinyl acetate resins, polyolefin resins (eg, polyethylene resins, polybutadiene resins). Resin), isocyanate resin, rosin resin, polyvinyl alcohol resin (PVA resin), imine resin and the like. Among these, acrylic resins and urethane resins are preferable, and urethane resins are more preferable. As the binder resin, only one kind may be used, or two or more kinds may be used.

  The solvent-dried printing layer, for example, after applying a printing ink produced by mixing the binder resin, a solvent, and, if necessary, the coloring pigment and other additives, using a printing machine It is provided by volatilizing the solvent.

  The printing layer constituting the printing layer (X) is a printing layer that does not substantially contain a curing agent (crosslinking agent) (that is, a layer that does not substantially contain a structural unit derived from the curing agent (crosslinking agent)). Preferably there is. When the print layer (X) is formed from a plurality of print layers, some of the print layers may be a print layer that substantially does not contain a curing agent, and all the print layers substantially contain a curing agent. Although there may be no printing layer, it is particularly preferable that all the printing layers forming the printing layer (X) are printing layers substantially free of a curing agent. When the printing ink which forms the said printing layer (X) (especially printing layer (X) containing urethane-type resin as binder resin) contains a hardening | curing agent, although the formed printing layer is comparatively high in hardness and excellent in tolerance, The printing suitability deteriorates, for example, viscosity changes occur during printing and color blurring tends to occur. Further, the cosmetics of the finished label tended to be inferior. However, by providing the protective printing layer of the present invention, since such a printing layer does not require a curing agent, a printing layer containing no or a small amount of the curing agent is excellent in printability. For this reason, in the plastic label of this invention, when the said printing layer (X) is a printing layer which does not contain a hardening | curing agent substantially, it is especially effective. Furthermore, the printing ink which forms the said printing layer (X) is excellent also in recyclability, and is economical by not containing a hardening | curing agent substantially.

  In addition, specifically, the above does not contain substantially, content with respect to the total weight (100 weight%) of the printing layer which comprises printing layer (X) is less than 5 weight%, for example (lower limit is, for example, 0 wt%), preferably less than 3 wt%, more preferably less than 1 wt%.

  Specifically, the curing agent preferably not substantially contained in the printing layer constituting the printing layer (X) is preferably an isocyanate curing agent, more preferably an isocyanate curing agent or an aziridine curing agent. More preferably, it is a curing agent having reactivity with a hydroxy group. In addition, the said aromatic polyisocyanate compound is contained in an isocyanate type hardening | curing agent.

  The printing layer which comprises the said printing layer (X) may contain components other than the above-mentioned each component within the range which does not impair the effect of this invention. The above components are not particularly limited, but additives (for example, lubricants, plasticizers, anti-settling agents, dispersants, stabilizers, antifoaming agents, fillers, antioxidants, ultraviolet absorbers, antistatic agents, colors) Anti-separation agent, perfume, deodorant, slip agent, etc.). The said component may use only 1 type and may use 2 or more types.

  The content of the binder resin in the printing layer (X) is not particularly limited, but is 10% by weight or more (for example, 10 to 100% by weight) with respect to the total weight (100% by weight) of the printing layer (X). Is more preferable, more preferably 20 to 95% by weight, still more preferably 30 to 90% by weight. When the printing layer (X) contains a color pigment, the content of the binder resin is not particularly limited, but is more preferably 10 to 90% by weight.

  Although the thickness of the said printing layer (X) is not specifically limited, For example, 0.1-15 micrometers is preferable, More preferably, it is 0.2-10 micrometers. If the thickness is less than 0.1 μm, it may be difficult to provide the printing layer (X) uniformly, which may cause partial “smear”, impair decorativeness, or difficult to print as designed. It may become. Further, if the thickness exceeds 15 μm, a large amount of printing ink is consumed, which increases the cost, makes it difficult to apply uniformly, and makes the printing layer (X) brittle and easy to peel off. There is a case.

[Label substrate]
The label base material (for example, the label base material 2 in FIG. 1) in the plastic label of the present invention serves as a support for the printing layer (X) and the protective printing layer of the present invention, and is mainly in the strength, rigidity and shrinkage characteristics of the label. affect.

  The label substrate includes at least a plastic film. The type of the plastic film can be appropriately selected according to the type of the plastic label, and is not particularly limited. For example, when the plastic label of the present invention is a shrink label (heat-shrinkable label), The plastic film is a shrink film (heat-shrinkable film), and when the plastic label of the present invention is a stretch label, the plastic film is a stretch film, and the plastic label of the present invention is a tack label, a roll label, or In the case of an in-mold label, it may be a heat-shrinkable film or a non-shrinkable film. Among these, the plastic film is preferably a heat-shrinkable film.

  The type of resin forming the plastic film can be appropriately selected according to the required physical properties, application, cost, etc., and is not particularly limited. For example, polyester resin, polyolefin resin (for example, polyethylene resin) Resin, polypropylene resin, etc.), polystyrene resin, polyvinyl chloride resin, polyamide resin, acrylic resin and the like. These resin may use only 1 type and may use 2 or more types. Furthermore, the same kind or different kinds of resins may be laminated to be used as a laminated film. In particular, from the viewpoint of further improving resistance to chemical components, polyester resins and polyolefin resins are preferable, and polyester resins are preferable. For example, the plastic film may be a polyester film having a polyester resin as a main component, a polyolefin film having a polyolefin resin as a main component, a polyester resin as an outer layer, and a polyolefin resin or a polystyrene resin as an inner layer. A laminated film is preferred. Examples of the polyester-based resin, polyolefin-based resin, and polystyrene-based resin include, for example, JP-A-2008-170822, JP-A-2008-170697, JP-A-2008-163215, and JP-A-2008-163231. The polyester-based resins and polyolefin-based resins described can be used. When the plastic film is a stretch film, a polyolefin film is preferable.

  Examples of the polyester resin used for the polyester film include polyethylene terephthalate (PET) resin, poly (ethylene-2,6-naphthalenedicarboxylate) (PEN), and polylactic acid (PLA). Among them, polyethylene terephthalate (PET) resin is preferable. As the PET resin, polyethylene terephthalate (PET) using terephthalic acid as the dicarboxylic acid component and ethylene glycol as the diol component; terephthalic acid as the dicarboxylic acid component, ethylene glycol as the diol component, Copolyester (CHDM copolymerized PET) using 4-cyclohexanedimethanol (CHDM) as a copolymerization component, terephthalic acid as a dicarboxylic acid component, ethylene glycol as a main component as a diol component, neopentyl glycol (NPG) as a main component Copolyester (NPG copolymerized PET) used as copolymer component, terephthalic acid as dicarboxylic acid component, ethylene glycol as main component as diol component, diethylene glycol as copolymer component Diol-modified PET such as copolymer polyester; dicarboxylic acid such as copolymer polyester using terephthalic acid as the main component, isophthalic acid and / or adipic acid as the copolymer component, and ethylene glycol as the diol component. Modified PET etc. are mentioned.

  Examples of the polystyrene-based resin used in the heterogeneous laminated film include, as constituent monomers, styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, p-isobutylstyrene, pt- Examples thereof include resins containing one or more styrene monomers such as butyl styrene and chloromethyl styrene. Specifically, for example, general-purpose polystyrene (GPPS), styrene-butadiene copolymer (for example, SBS), styrene-butadiene-isoprene copolymer (SBIS), styrene-acrylic acid ester copolymer and the like can be mentioned. .

  Polyolefin resins used for the polyolefin film include polyethylene resins such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), metallocene catalyst LLDPE (mLLDPE), and ethylene-vinyl acetate copolymer. Polypropylene resins such as polypropylene and propylene-α-olefin copolymers; cyclic olefin resins and the like. In particular, the polyolefin film preferably has a cyclic olefin resin as an outer layer, and preferably has a cyclic olefin resin as an outer layer and a polyethylene resin or a polypropylene resin as an inner layer (center layer).

  The plastic film may have a single-layer structure or a laminated structure. That is, the plastic film may be a single layer film or 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 the same kind of resin may be laminated, or film layers made of different resins may be laminated. In the case of a laminated film, a laminated film having a polyester resin as an outer layer and a polyolefin resin or polystyrene resin as an inner layer, or a laminated film having a cyclic olefin resin as an outer layer and a polyethylene resin or a polypropylene resin as an inner layer is preferable.

  The plastic film may be a non-oriented film or an oriented film. Among these, when the plastic film is a heat-shrinkable film, a film oriented in at least one direction (for example, a film oriented in one direction, A film oriented in a direction different from one direction) is preferred. When the heat-shrinkable film is a laminated film, it is preferable that at least one film layer in the laminated film is oriented, and that all the film layers are oriented in at least one direction. When all the film layers are non-oriented, sufficient shrink characteristics may not be exhibited. As the heat-shrinkable film, a film oriented in one direction (uniaxially oriented film) or a film oriented in one direction and a direction orthogonal to one direction (biaxially oriented film) is often used. An axially oriented film (including a film stretched substantially in one direction, mainly stretched in one direction and slightly stretched in a direction perpendicular to the one direction) is generally used. When the plastic film is a stretch film, it may be a non-oriented film, but may be slightly oriented (for example, oriented by stretching less than 1.5 times). When the plastic film is a non-shrinkable film, it may be a non-oriented film, slightly oriented (for example, oriented by stretching less than 1.5 times), or a biaxially oriented film. Although a biaxially oriented film may be used most commonly.

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

  The plastic film 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 plastic film. When producing a laminated plastic film, a conventional method such as a co-extrusion method or a dry lamination method can be used as a method for lamination. Examples of the method for orienting the plastic film include 2 in the longitudinal direction (film production line direction; also referred to as longitudinal direction or MD direction) and the width direction (direction perpendicular to the longitudinal direction; also referred to as lateral direction or TD direction). Stretching in the direction, stretching in one direction of the longitudinal direction or the width direction, and the like can be used. As the stretching method, for example, a roll method, a tenter method, a tube method, or the like can be used. For example, the stretching process of a film stretched substantially in one direction in the width direction is, for example, 1.01 to 1.5 times, preferably 1. After stretching about 05 to 1.3 times, the stretching can be performed by stretching 3 to 8 times, preferably about 4 to 7 times in the width direction.

  When the plastic film is a heat-shrinkable film, the heat-shrinkable film may be referred to as a “heat-shrinkage rate (90 ° C., 10 seconds)” at 90 ° C. for 10 seconds in the main shrinkage direction. There is no particular limitation, but it is preferably 30 to 90%, more preferably 40 to 85%. The heat shrink rate (90 ° C., 10 seconds) in the direction perpendicular to the main shrink direction of the heat shrinkable film is not particularly limited, but is preferably −3 to 15%. The “main shrinkage direction” is a direction having the largest thermal shrinkage rate, and is generally a direction mainly stretched, for example, a film stretched substantially in one direction in the width direction. In the case of the width direction.

  Moreover, when the said plastic film is a non-shrinkable film, the heat shrink rate (90 degreeC, 10 second) of a plastic film is although it does not specifically limit, It is preferable not to exceed 5% in any direction.

  When the plastic film is a stretch film, the stretch film can be stretched 1.25 times or more in at least one direction, and the strain after stretching 1.25 times is a stretch before stretching 1.25 times. The film length is preferably 10% or less, assuming that the length of the film is 100%. The strain can be measured using, for example, a known or conventional tensile tester. Examples of the tensile tester include “Shimadzu Autograph (AGS-50G: load cell type 500N)” manufactured by Shimadzu Corporation. Note that JIS K 7161 can be referred to for test conditions and the like as necessary.

  A commercially available product can be used as the plastic film used as the label substrate. Examples of the heat-shrinkable film include “Space Clean S7042” and “SV-808” manufactured by Toyobo Co., Ltd., “LX-10S”, “LX-18S”, and “LX-61S” manufactured by Mitsubishi Plastics, Inc. (Polyester film); Cbon Kasei Co., Ltd. “Bonset”, Gunze Co., Ltd. “GMLS” (Polystyrene film); Gunze Co., Ltd. “FL” (Polyolefin film); Mitsubishi Resin Co., Ltd. “Eco-Rouge” (polylactic acid film); Mitsubishi Plastics Co., Ltd. “DL”, Gunze Co., Ltd. “HGS” (The surface layer is a polyester resin and the center layer is a laminate of polystyrene resin. Film) and the like. Examples of the stretch film include “Suzuron L” manufactured by Aicello Chemical Co., Ltd. Examples of the non-shrinkable film include “OP” and “FOS” manufactured by Mitsui Chemicals Tosero Co., Ltd., “Trephan” manufactured by Toray Industries, Inc. (hereinafter referred to as biaxially stretched polypropylene film), and the like.

  The label base material may have a layer other than the plastic film. Examples of the layer other than the plastic film include an anchor coat layer, a primer coat layer, a protective layer, an antistatic layer, a sliding layer, a heat insulating layer, and a metal or metal oxide vapor deposition layer. Further, the surface of the plastic film may be subjected to conventional surface treatment such as corona discharge treatment, primer treatment, antistatic coating treatment, etc., if necessary.

  When the plastic film is transparent, the haze value [based on JIS K 7136, converted to a thickness of 40 μm, unit:%] of the plastic film is not particularly limited, but is preferably 10% or less, more preferably It is 7% or less, more preferably 5% or less. When the haze value exceeds 10%, the inside of the label base material (the side that becomes the container side when the plastic label is attached to the container) is printed, and the plastic label that shows the print through the label base material (back printing) In the case of (plastic label) applications, when the product is used, printing may become cloudy and decorativeness may deteriorate. However, even when the haze value exceeds 10%, it may be opaque in applications other than the above-described applications (printed plastic labels) that show printing through the label base material, and can be used sufficiently. Moreover, it does not specifically limit as a plastic film in an opaque label base material, For example, a milky white film, a metal vapor deposition film, etc. can be used.

  Although the thickness of the said plastic film is not specifically limited, 10-150 micrometers is preferable. In the case of a heat-shrinkable film or a non-shrinkable film, 10 to 100 μm is preferable, more preferably 12 to 80 μm, and still more preferably 15 to 60 μm. In the case of a stretch film, 50 to 150 μm is preferable.

[Other layers]
The other layers (layers other than the label base material, the printing layer (X), and the protective printing layer of the present invention) are not particularly limited. For example, a protective layer other than the protective printing layer of the present invention, an adhesive layer. (Pressure-sensitive adhesive layer, heat-sensitive adhesive layer, etc.), anchor coat layer, primer coat layer, coating layer, inner coat layer, antistatic layer, metal or metal oxide deposition layer, light shielding layer, heat insulation layer, barrier A layer, a sliding layer, and the like. Moreover, as said other layer, printing layers other than the said printing layer (X), ie, the printing layer which is not covered with the protective printing layer of this invention, is mentioned.

[Plastic label]
The plastic label of the present invention preferably has the protective printing layer of the present invention on the surface of the plastic label. Since the region sandwiched between the protective printing layer of the present invention and the label substrate is protected from chemical components, the protective printing layer of the present invention is protected from the chemical components by having the protective printing layer of the present invention on the surface of the plastic label of the present invention. The area is maximized.

  The plastic label of the present invention may be a front printed plastic label, a back printed plastic label, or a double-sided printed plastic label, but a back printed plastic label is preferred. In this specification, the front printed label is a label that shows printing without passing through the label base material, and means a label having a design print layer in front of the label base material when the label is viewed. Moreover, a back printed label is a label which shows printing through a label base material, and means the label which has a design printing layer in the back | inner side rather than a label base material when seeing a label. Moreover, a double-sided printing label means the label which has a design printing layer on the both surfaces side of a label base material.

  The plastic label of the present invention is not particularly limited, and examples thereof include stretch labels, shrink labels (including stretch shrink labels), in-mold labels, tack labels, roll labels (wrap-type glued labels), thermal labels, and the like. It is done. Among these, a shrink label, a roll label, and a heat sensitive label are preferable, and a shrink label is particularly preferable. When the plastic label of the present invention is a shrink label, it is particularly useful because it is stable before and after heat shrinkage and excellent in resistance to chemical components.

  Although the thickness (total thickness) of the plastic label of this invention is not specifically limited, 10-170 micrometers is preferable. In the case of shrink labels, in-mold labels, roll labels, and heat-sensitive labels, the thickness is preferably 10 to 120 μm, more preferably 15 to 90 μm, and still more preferably 20 to 65 μm. In the case of a tack label, 25 to 150 μm is preferable. In the case of a stretch label, 50 to 170 μm is preferable.

(Preferred embodiment of the plastic label of the present invention)
A preferred first embodiment of the plastic label of the present invention will be described with reference to FIG. In the first embodiment, in FIG. 1, the label substrate 2 is a polyester-based heat-shrinkable film, and the printing layer (X) 3 is a design printing layer using a urethane-based resin as a binder resin. The protective printing layer 4 is a shrink label which is a back printing layer containing a reaction product of the urethane resin of the present invention and an aromatic polyisocyanate compound, titanium oxide, and a lubricant. In the shrink label, the protective printing layer of the present invention comprises 8 total urethane resin and aromatic polyisocyanate compound based on the total weight (100% by weight) of the protective printing layer of the present invention. -70 wt% (preferably 13-65 wt%, more preferably 15-60 wt%), 5-89 wt% titanium oxide (preferably 20-85 wt%, more preferably 30-80 wt%), It is a white back printed layer containing 1 to 20% by weight of a lubricant. The shrink label is a back printed shrink label in which the heat-shrinkable film is transparent (preferably colorless and transparent) and printing is shown through the heat-shrinkable film.

  In the shrink label illustrated in FIG. 1, the design printing layer is partially provided on one surface of the heat-shrinkable film. The design print layer is formed of a plurality of print layers having different color pigments so as to have a desired design. The plurality of printed layers do not contain a curing agent. For this reason, when the printing ink which forms the said several printing layer remains, it can be reused. The design print layer may be transparent or opaque. The thickness of the design printing layer is not particularly limited, but is preferably 0.1 to 8 μm.

  The back print layer is provided on one surface of the heat-shrinkable film so as to cover the design print layer. Specifically, the back print layer is formed in a wider area than the design print layer, and is provided so as to cover the entire surface of the design print layer. The back printing layer is partially provided on one surface of the heat-shrinkable film, but may be provided on the entire surface. In particular, the back printed layer is preferably provided on the entire surface other than the portion that becomes the seal portion when the cylindrical shrink label is formed. The back printed layer is a printed layer that becomes the background of the design printed layer when observed from the outside of the cylinder when the shrink label is a cylindrical shrink label. Although the thickness of a back surface printing layer is not specifically limited, 0.5-10 micrometers is preferable. In the first embodiment, the back print layer is opaque, but may be transparent.

  The shrink label according to the first embodiment uses the protective printing layer of the present invention as the back printing layer. That is, the protective printing layer of the present invention has a role as a back printing layer and a role of protecting the design printing layer from dissolution by chemical components. When the shrink label has the above-described configuration, the hardness of the back printing layer which is the protective printing layer of the present invention is increased, or the adhesion of the back printing layer to the heat-shrinkable film and / or the design printing layer is improved. In addition, it is assumed that the aromatic polyisocyanate compound in the back printing layer penetrates into the design printing layer and reacts with the urethane resin in the design printing layer. High resistance to And the label excellent in the tolerance with respect to a chemical component can be obtained, without adding a layer to the structure of the conventional shrink label which has a heat-shrinkable film, a design printing layer, and a back surface printing layer.

  A preferred second embodiment of the plastic label of the present invention will be described with reference to FIG. FIG. 2 is a schematic view (partial sectional view) showing a second preferred embodiment of the plastic label of the present invention. The plastic label of the present invention shown in FIG. 2 is a shrink label 5 having a heat-shrinkable film 6, a design printing layer 7, a back printing layer 8, and a transparent printing layer 9. The shrink label 5 shown in FIG. 2 is a back-printed shrink label in which the heat-shrinkable film 6 is transparent (preferably colorless and transparent) and printing is shown through the heat-shrinkable film 6.

  The heat-shrinkable film 6 corresponds to a label substrate and is a laminated film having a polyester resin as an outer layer and a polystyrene resin as an inner layer. Specifically, it has two outer layers containing 80% by weight or more of a polyethylene terephthalate resin and an inner layer containing 50% by weight or more of a polystyrene resin located between the two outer layers, preferably the outer layer and the inner layer. Is a laminated film having an adhesive resin layer therebetween. Examples of the adhesive resin layer include those that can improve the adhesion between the inner layer and the outer layer. For example, a mixed resin layer of a polyethylene terephthalate resin and a polystyrene resin, a soft polyethylene terephthalate resin layer, a soft polystyrene resin Layer and the like.

  The design print layer 7 corresponds to the print layer (X), and is partially provided on one surface of the heat-shrinkable film 6. The design printing layer 7 is a design printing layer using a urethane-based resin as a binder resin, similarly to the design printing layer in the first embodiment, and a plurality of printings with different color pigments so as to have a desired design. Formed by layers. The plurality of printing layers do not contain a curing agent, and can be reused when printing ink for forming the plurality of printing layers remains. The design print layer 7 is transparent but may be opaque. Although the thickness of the design printing layer 7 is not specifically limited, 0.1-8 micrometers is preferable. Unlike the first embodiment, the design print layer 7 includes a design print layer covered with the back print layer 8 and a design print layer not covered with the back print layer 8.

  The back printing layer 8 corresponds to the printing layer (X), not the protective printing layer of the present invention, and is provided on one surface of the heat-shrinkable film 6 so as to cover a part of the design printing layer 7. . Specifically, the back print layer 8 is formed in a wider area than the part of the design print layers 7. The back printed layer 8 is composed of 10 to 90% by weight of urethane resin and 10 to 90% by weight of titanium oxide (preferably urethane resin) as a binder resin with respect to the total weight (100% by weight) of the back printed layer 8. 15 to 70% by weight and titanium oxide 30 to 85% by weight). In the shrink label 5, a region where the back printing layer 8 is provided is opaque, and a region where the back printing layer 8 is not provided is transparent.

  The transparent printing layer 9 corresponds to the protective printing layer of the present invention, is a transparent layer, and is provided on one surface of the heat-shrinkable film 6 so as to cover the back printing layer 8 and the design printing layer 7. . The transparent printing layer 9 is partially provided on one surface of the heat-shrinkable film 6, but may be provided on the entire surface. In particular, the transparent printing layer 9 is preferably provided on the entire surface other than the vicinity of the portion that becomes the seal portion when the cylindrical shrink label is formed.

  The transparent printing layer 9 is 50 to 99% by weight (preferably 60 to 97% by weight) of the urethane resin and the aromatic polyisocyanate compound of the present invention based on the total weight (100% by weight) of the transparent printing layer 9. %, More preferably 70 to 95% by weight), and a layer containing 1 to 20% by weight of a lubricant. Although the thickness of the transparent printing layer 9 is not specifically limited, 0.5-10 micrometers is preferable. The transparent printing layer 9 is preferably colorless and transparent.

  The shrink label 5 shown in FIG. 2 as the second embodiment uses a printing layer that is not the protective printing layer of the present invention as the back printing layer 8 and uses the protective printing layer of the present invention as the transparent printing layer 9. . That is, the shrink label shown in FIG. 2 has the protective printing layer of the present invention which is not mainly intended to serve as the back printing layer. Thereby, the label which is especially excellent in the tolerance with respect to a chemical component can be obtained. Moreover, by having the said structure, the hardness of the transparent printing layer 9 which is a protective printing layer of this invention raises, or the heat-shrinkable film 6, the design printing layer 7, and / or the back surface printing layer 8 of the transparent printing layer 9. The aromatic polyisocyanate compound in the transparent printing layer 9 penetrates into the design printing layer 7 and the back printing layer 8 and reacts with the urethane resin in the design printing layer 7 and the back printing layer 8. This is presumed to be due to the fact that it has a high resistance to chemical components stably before and after thermal contraction.

  In the second embodiment, the back printed layer 8 is partially provided to form a label having an opaque region and a transparent region. However, the back printed layer 8 is not provided, and the whole is a transparent region. It can be a label.

  The plastic label of the present invention is, for example, a cylindrical plastic label (for example, a cylindrical shrink label, a cylindrical stretch label, etc.) that is attached to an adherend after sealing both ends with a solvent or an adhesive to form a cylindrical shape. Roll-on shrink-on label (ROSO label) or one end of the label is attached to the adherend with an adhesive or the like, the label is wound around the adherend, and the other end is overlapped on one end to form a cylinder It can be used as a plastic label of a type (winding type shrink label, tack label, heat sensitive label). The plastic label of the present invention is particularly preferably used for a cylindrical plastic label. That is, the plastic label of the present invention is preferably a cylindrical plastic label. Hereinafter, the cylindrical plastic label using the plastic label of the present invention may be referred to as “the cylindrical plastic label of the present invention”.

(Cylindrical plastic label)
The cylindrical plastic label of the present invention preferably has the protective printing layer of the present invention on the innermost surface (the innermost surface when it is cylindrical). When a cylindrical plastic label, which is a back printed label, is attached to a container or the like, it is necessary to protect the printed layer (X) including the design and the like inside the label base material from chemical components. By having the layer on the innermost surface of the cylindrical plastic label of the present invention, the printed layer (X) is appropriately protected from chemical components.

  An example of a cylindrical shrink label which is a preferred embodiment of the plastic label of the present invention will be described with reference to FIGS. 3 and 4. A cylindrical shrink label 10 shown in FIG. 2 is formed by forming a shrink label including a label base material that is a heat-shrinkable film formed in a rectangular shape, a printing layer (X), and the protective printing layer of the present invention. A cylindrical body in which the other end is overlapped on the outside of one end of the label to form a cylinder, and the inner surface of the other end and the outer surface of the one end are joined with a solvent or an adhesive to form a seal portion 11. The tubular shrink label 10 is formed into a tubular shape so that the main shrink direction of the heat-shrinkable film is the circumferential direction D of the tubular shrink label, and is heat shrinkable in that direction.

  4 is a cross-sectional view taken along the line IV-IV 'in FIG. Specifically, the shrink label has a printing layer (X) 3 in a region excluding a region having a predetermined width from an end 42 at the other end of one surface of the label base 2 (the inner surface of the cylindrical body). The protective printing layer 4 of the present invention is formed over substantially the entire region excluding the region of a predetermined width from the end 42 at the other end of the one surface of the label base 2 so as to cover the printing layer (X) 3 formed. Is formed. For this reason, in the shrink label, the printing layer (X) 3 and the protective printing layer 4 of the present invention are not formed in the region having a predetermined width from the end 42 at the other end, and the label base 2 is exposed. A label substrate exposed surface is formed. Specifically, the cylindrical shrink label 10 includes a label base material exposed surface formed on the inner surface side of the other end portion of the shrink label and a label base material exposed surface formed on the outer surface side of the one end portion. Or it is joined by the adhesive 12. The printing layer (X) 3 and the protective printing layer 4 of the present invention may each be a single layer or multiple layers. Moreover, the layer structure of the cylindrical shrink label in FIG. 3 and FIG. 4 is not limited to the layer structure shown in FIG. 3 and FIG. 4 (that is, the layer structure of the plastic label of the present invention shown in FIG. 1), Other layer configurations (for example, the layer configuration shown in FIG. 2) may be used.

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

  In addition, in the cylindrical shrink label 10 shown by FIG.3 and FIG.4, although the joining form (envelope sticking) which joins the inner surface of an other end part and the outer surface of one end part was shown as the seal | sticker part 11, this invention The form of joining in the cylindrical plastic label is not limited to this, and the inner surface of one end and the other end or the outer surfaces are overlapped, and the overlapped portion is heat-sealed. It is also possible to use a joining form that joins together (joint palm attachment). Even in this case, it is preferable that the exposed surfaces formed on the inner surface side or the outer surface side are overlapped and joined.

  Moreover, in the cylindrical shrink label 10 in FIG. 4, one end portion extends to a position where the end 41 overlaps the protective printing layer 4 of the present invention at the other end portion. A region where the protective printing layers 4 overlap each other is formed. For this reason, there is no region in which no printed layer exists in the thickness direction. As shown in FIG. 4, the cylindrical shrink label may have a structure that overlaps the end 41 at one end and the protective printing layer 4 of the present invention on the other end, and the end of the one end is at the other end. It extends to the area overlapping with the label substrate exposed surface, and the end of one end is not extended to the position overlapping the protective printing layer 4 of the present invention on the other end. The structure which does not overlap with the protective printing layer 4 may be sufficient.

  The plastic label of the present invention has a printing layer and a protective printing layer provided so as to cover the printing layer on at least one surface of the label substrate. And the said protective printing layer is a layer containing the reaction material of the urethane type resin which contains the structural unit derived from a polyester polyol as a main component of a polyol component, and an aromatic polyisocyanate compound. The plastic label of the present invention is characterized in that an aromatic polyisocyanate compound is used as a protective printing layer, among a number of isocyanate compounds, in combination with a specific urethane resin. By having such a structure, the plastic label of the present invention can stably obtain a label having excellent resistance to chemical components. Specifically, when the urethane-based resin of the present invention and the aromatic polyisocyanate compound in the protective printing layer of the present invention are sufficiently reacted, the protective printing layer of the present invention is hard, the printing layer ( It is presumed to be caused by high adhesion to the printing layer (X)), high adhesion to the label base material, etc., but in a container filled with highly soluble contents Even if it exists, the printing layer which comprises a design etc. is hard to melt | dissolve with this content, and is excellent in the tolerance with respect to a chemical component stably. On the other hand, when the reaction between the urethane-based resin of the present invention and the aromatic polyisocyanate compound in the protective printing layer of the present invention is insufficient, a plastic label having excellent resistance to chemical components is obtained by advancing the reaction. Therefore, a label having excellent resistance to chemical components can be obtained. Moreover, when the plastic label of this invention is a shrink label, it is excellent also in the followable | trackability with respect to the heat shrink of a heat shrink film of printing layer (X) and the protective printing layer of this invention.

  Moreover, in the conventional plastic label, in order to make the tolerance with respect to a chemical component high, the method of adding a hardening | curing agent to the printing layer which comprises a design etc. was sometimes taken. However, such a printing layer has a relatively high hardness and is excellent in the above-described durability. However, the printing suitability may be deteriorated, for example, a viscosity change occurs during printing and color blurring is likely to occur. As a result, the cosmetics of the finished label may be inferior. On the other hand, since the printed layer constituting the design or the like in the plastic label of the present invention does not require a curing agent, if the printed layer constituting the design or the like does not contain a curing agent or a small amount, the color tone changes. Hateful. Furthermore, when the printing layer which comprises a design etc. does not contain a hardening | curing agent or makes it a small quantity, the printing ink which forms the said printing layer is excellent also in recyclability, and is economical.

[Production method and processing method of plastic label of the present invention]
Examples of the manufacturing method and processing method of the plastic label of the present invention (such as a manufacturing method of a cylindrical plastic label) are shown below.

  The method for producing a plastic label of the present invention comprises a step of forming a printing layer (X) on at least one surface of a label substrate (printing layer (X) forming step), and a method for forming a label on at least one surface of the label substrate. It includes at least a step of forming the protective print layer of the invention (protective print layer forming step of the present invention).

(Printing layer (X) formation process)
In the printing layer (X) formation step, the printing layer (X) is formed by applying a printing ink for forming the printing layer (X) on at least one surface of the label base material and solidifying the layer by drying or curing. It is formed. As a method for applying the printing ink, known and usual methods can be used, and among them, gravure printing, flexographic printing, and digital printing are preferable. When the printing layer (X) is a design printing layer, in the stage of providing the design printing layer, generally, the printing ink is applied a plurality of times for each color, and the printing layer (X ) Is formed.

  When a solvent-drying type printing ink is used, the printing layer (X) is formed by applying the printing ink to form a coating film, drying and removing the solvent from the coating film, and solidifying the coating film. it can.

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

  As said solvent, the water normally used for the printing ink used for gravure printing, flexographic printing, etc., an organic solvent, etc. can be used. Examples of the organic solvent include esters such as acetate (eg, ethyl acetate, propyl acetate, butyl acetate); alcohols such as methanol, ethanol, isopropyl alcohol, propanol, and butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; Aromatic hydrocarbons such as xylene, aliphatic hydrocarbons such as hexane and octane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, glycols such as ethylene glycol and propylene glycol, ethylene glycol monopropyl ether and propylene glycol monomethyl ether Glycol ethers such as propylene glycol monobutyl ether; glycol ether esters such as propylene glycol monomethyl ether acetate . The solvent can be removed by drying after applying the printing ink to the label substrate. The solvent includes the meaning of “dispersion medium”.

(Protective printing layer forming step of the present invention)
In the protective printing layer forming step of the present invention, a composition (printing ink or the like) for forming a protective printing layer so as to cover the printing layer (X) on the surface of the label base on the side having the printing layer (X) Is applied and solidified by drying or the like to form a printed layer. In the said printing layer, the urethane type resin of this invention and an aromatic polyisocyanate compound react, and the protective printing layer of this invention is formed.

  When the protective printing layer of the present invention is a solvent-drying type printing layer, a composition for forming the protective printing layer of the present invention is applied on the surface of the label base material having the printed layer (X), and necessary A printed layer is formed by drying and solidifying accordingly. A general heating device that can be dried on a printing device when the applied composition layer (coating layer) is dried by heating, air blowing (for example, cold air, normal temperature air, hot air) or the like. A blower can be preferably used. From the viewpoint of safety and drying efficiency, a hot air heater or the like can be preferably used as the heating device.

  As a method for applying the composition, from the viewpoints of cost, productivity and the like, a gravure printing method and a flexographic printing method are preferable, and a gravure printing method is particularly preferable.

  The said composition is manufactured by mixing the urethane type resin of this invention, an aromatic polyisocyanate compound, a solvent, and another component as needed, for example. The mixing can be performed by a known or conventional mixing method, and is not particularly limited. For example, a mixing device illustrated and described as a mixing device for printing ink for forming the above-described printing layer (X) can be used. The mixing time (retention time) during mixing is not particularly limited, but is preferably 10 to 120 minutes. The obtained composition may be used after being filtered, if necessary. Each of the above components (the urethane resin of the present invention, the aromatic polyisocyanate compound, the solvent, and other components) may be used alone or in combination of two or more.

  As said solvent, the organic solvent etc. which are normally used for printing ink can be used. As said solvent, the organic solvent etc. which were illustrated and demonstrated as the organic solvent which may be contained in the printing ink which forms the above-mentioned printing layer (X) are mentioned, for example. The solvent can be removed by drying after applying the composition to a label substrate.

  Although the viscosity (23 ± 2 ° C.) of the composition is not particularly limited, for example, when applied by gravure printing, 10 to 1000 mPa · s is preferable, and 20 to 500 mPa · s is more preferable. The viscosity of the composition can be controlled by the type and blending amount (content) of the urethane resin, aromatic polyisocyanate compound and other components of the present invention, a thickener, a thinning agent, and the like. . In the present specification, unless otherwise specified, “viscosity” is JIS Z using an E-type viscometer (conical plate-type rotational viscometer) under the conditions of 23 ± 2 ° C. and the rotational speed of a cylinder of 50 rotations. The value measured according to 8803 is meant.

  The printing layer formed as described above becomes the protective printing layer of the present invention by the reaction of the urethane resin of the present invention and the aromatic polyisocyanate compound in the printing layer. Examples of the reaction between the urethane resin of the present invention and the aromatic polyisocyanate compound include active energy ray curing, thermal curing, two-component reaction curing, and the like as described above. The said thermosetting can be performed using well-known thru | or usual heating apparatuses, such as a warm air heater, an infrared heater, and a thermostat. In the two-component reaction curing, the reaction may proceed over time at normal temperature (for example, 15 to 25 ° C.) or may not proceed at normal temperature. In the case of two-component reaction curing in which the reaction proceeds at room temperature, the two-component reaction curing does not require any operation other than mixing the two components. In this case, for example, curing can be performed by performing an aging treatment for 8 to 48 hours in a constant temperature bath (or a constant temperature and humidity chamber) having the predetermined temperature. In the case of two-component reaction curing that does not proceed or is difficult to proceed at normal temperature, the reaction may be promoted using a heating device, a humidity control device, an active energy ray irradiation device, or the like in order to promote the reaction.

  In the case where the two-component reaction curing is performed with the passage of time from the time when the two components (for example, the liquid containing the urethane resin of the present invention and the liquid containing the aromatic polyisocyanate compound) are mixed, the printed layer is formed. Since the reaction between the urethane resin of the present invention and the aromatic polyisocyanate compound has started in the previous composition, the printed layer contains the reaction product of the urethane resin of the present invention and the aromatic polyisocyanate compound. The printed layer corresponds to the protective printed layer of the present invention.

  As described above, the plastic label of the present invention in which the printing layer (X) and the protective printing layer of the present invention are formed on at least one surface of the label substrate can be produced.

(Method for manufacturing cylindrical plastic labels)
Although the manufacturing method of the cylindrical plastic label of this invention is not specifically limited, For example, it is as follows. The long plastic label of the present invention is slit to a predetermined width to obtain a long label body in which a plurality of the plastic labels of the present invention are continuous in the longitudinal direction (longitudinal direction). The long surface of the label is formed so that the width direction (that is, the width direction of the label base material) is the circumferential direction. The surfaces are overlapped to form a cylinder, the overlapped portion is sealed in a band shape with a predetermined width, and both ends are joined, or the long label body has a circumferential direction in the width direction. In this way, the other end is overlapped so as to be outside the one end, and is formed into a cylindrical shape. The overlapped portion is sealed in a band shape with a predetermined width, and both ends are joined together to form a long cylindrical label. A continuous body (long cylindrical plastic label) can be obtained. By cutting the long cylindrical plastic label in the circumferential direction, one cylindrical plastic label (the cylindrical plastic label of the present invention) having a predetermined length in the height direction can be obtained.

[Container with label]
Although the plastic label of this invention is not specifically limited, It mounts | wears with a container and is used as a labeled container. In addition, the plastic label of this invention may be used for to-be-attached objects (adhered body) other than a container. For example, by attaching a plastic label of the present invention (particularly, a cylindrical plastic label) to a container, a labeled container (a labeled container having the plastic label of the present invention) can be obtained. Examples of the containers include soft drink bottles, milk bottles for home delivery, seasonings, cup noodles and other food containers, alcoholic beverage bottles, pharmaceutical containers, detergents, sprays and other chemical product containers, and toiletry containers. Etc. are included. Although it does not specifically limit as a shape of the said container, For example, various shapes, such as bottle types, such as cylindrical shape and a square shape, and a cup type, are mentioned. The material of the container is not particularly limited, and examples thereof include plastics such as polyethylene terephthalate resin and olefin resin, glass, and metal.

  The cylindrical plastic label can be attached to the container by a known or conventional method. For example, for a plastic bottle with a label, the cylindrical plastic label of the present invention formed into a cylindrical shape is supplied to an automatic label mounting apparatus, cut into a required length, and then into a plastic bottle that is normally filled with contents. It can be manufactured by continuously fitting so as to cover almost the entire side surface or a predetermined part of the side surface of the bottle body, and if necessary, heat shrinking by heating.

  When the plastic label of the present invention is a shrink label, specifically, for example, after the tubular shrink label is externally fitted to a predetermined container, the tubular shrink label is thermally contracted by heat treatment, and is brought into close contact with 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 heat-shrinkable film will be 85-100 degreeC (especially 90-97 degreeC). Moreover, the processing time of heat processing has preferable 4 to 20 second from a viewpoint of productivity and economical efficiency.

  On the other hand, when the plastic label of the present invention is a stretch label, specifically, for example, the cylindrical stretch label having a diameter smaller than the minimum diameter of the portion to which the label of the container as the attachment object is attached is applied by an external force. By expanding the outer diameter of the container to be attached to the container and fitting it externally to the container, and then releasing the external force, the cylindrical stretch label is self-contracted to follow and adhere to the container. Can be manufactured.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In addition, in Table 1, the structure of the shrink label produced by the Example and the comparative example, the evaluation result, etc. were shown. Table 2 shows the details (product name, manufacturer name, etc.) of the raw materials in the printing ink used in the examples and comparative examples.

Example 1
(Printing ink)
Urethane resin solution (trade name “TA24-242”, manufactured by Hitachi Chemical Co., Ltd.), acrylic beads, olefin wax, silicone wax, and solvent are mixed at a ratio shown in Table 1, and dispersed using a mixer. A printing ink was obtained.

(Shrink label)
Polyester (PET) film (heat-shrinkable film) (Mitsubishi Resin Co., Ltd., trade name “LX-18S”, thickness: 40 μm) on one side with urethane color ink (trade name “NT Hiramic Red”, large Nissei Kasei Co., Ltd.) is coated and dried using a tabletop gravure printing machine (trade name “GRAVO PROOF MINI”, Nissho Gravure Co., Ltd.), and color printing is performed on the entire surface other than the part that becomes the seal part. A layer was formed. Next, the printing ink obtained above and the trade name “VM Hardener XB” (manufactured by Toyo Ink Co., Ltd.) were mixed on the surface of the color printing layer using a mixer so as to have the ratio shown in Table 1. The product was applied, dried and solidified using the above table gravure printing machine, and then subjected to an aging treatment at 27 ± 3 ° C. for 24 hours to form a protective printing layer on the entire surface other than the portion to be a seal portion.

  As described above, a shrink label having a laminated structure of PET film (thickness: 40 μm) / color printing layer (thickness: 1 μm) / protective printing layer (thickness: 1 μm) was obtained.

Examples 2, 3 and Comparative Examples 1-3
A shrink label was obtained in the same manner as in Example 1 except that the printing ink and polyisocyanate compound having the composition shown in Table 1 were used as the printing ink and polyisocyanate compound.

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

(1) Resistance to chemical components (drop test)
A test piece cut to 25 mm × 80 mm from the shrink label obtained in the example and the comparative example is pasted on the mount, and a predetermined test solution is placed in three locations of 0.1 ml each on the portion where the print layer of the test piece is provided. And left at 40 ° C. for 24 hours. Then, while flowing tap water through the test piece, rub the test part 20 times with a finger lightly to wash the test solution, and then visually observe the state of the printed layer dripped from the label substrate side. Resistance was evaluated according to the following criteria. Table 1 shows the test solutions used in the drop test and the evaluation results.
Good resistance to chemical components (◎): No resistance to peeling of the color printing layer (○): Poor resistance to chemical components with peeling of less than 10% in the color printing layer (x) : 10% or more peeling on the color printing layer

(2) Resistance to chemical components (immersion test)
The test pieces cut into 25 mm × 80 mm from the shrink labels obtained in Examples and Comparative Examples were put into a sealable container. An amount of a predetermined test solution into which the test piece was immersed was poured into the container and left at 40 ° C. for 24 hours. Thereafter, the test piece is taken out from the container, and while flowing tap water through the test piece, the part provided with the printing layer is lightly rubbed 20 times with a finger to wash away the test solution, and then the state of the printing layer is started from the label substrate side. It visually observed and the tolerance with respect to a chemical component was evaluated on the following reference | standard. Table 1 shows the test solutions used in the drop test and the evaluation results.
Good resistance to chemical components (◎): No peeling of color printing layer Available level of resistance to chemical components (○): Less than 10% peeling of color printing layer Poor resistance to chemical components (x): Color More than 10% peeling of printed layer

(3) Adhesion (resistance to scratching)
From the shrink labels obtained in Examples and Comparative Examples, a measurement sample of 100 mm (main shrinkage direction) × 100 mm (perpendicular to the main shrinkage direction) was collected. Hold both ends of the sample for measurement with both hands, and even 10 times. The protective printing layer on the surface of the measurement sample was visually observed, and the adhesion was evaluated according to the following criteria. The evaluation results are shown in Table 1.
Adhesion is good (○): No peeling Adhesive level (△): There is peeling along the heel Adhesion is poor (×): There is also peeling around the heel

  As can be seen from the evaluation results, the shrink label (Example) which is a plastic label of the present invention was excellent in adhesion. Moreover, it was excellent in the tolerance with respect to a chemical component compared with the shrink label of a comparative example.

DESCRIPTION OF SYMBOLS 1 Plastic label of this invention 2 Label base material 3 Printing layer (X)
DESCRIPTION OF SYMBOLS 4 Protective printing layer of this invention 5 Shrink label 6 Heat-shrinkable film 7 Design printing layer 8 Back surface printing layer 9 Transparent printing layer 10 Cylindrical shrink label 11 Seal part 12 Solvent or adhesive agent 41 End of one end part 42 End of other end part end

Claims (5)

A label substrate comprising a plastic film;
A printed layer provided on at least one surface of the label substrate;
A protective printing layer provided to cover the printing layer,
The plastic label, wherein the protective printing layer contains at least a reaction product of a urethane resin containing a structural unit derived from polyester polyol as a main component of a polyol component and an aromatic polyisocyanate compound.   The plastic label according to claim 1, wherein a proportion of the structural unit derived from the polyester polyol with respect to the total weight of the structural unit derived from the polyol compound in the urethane-based resin is 50% by weight or more.   The plastic label according to claim 1, wherein the protective printing layer is provided on a surface of the plastic label.   A cylindrical plastic label using the plastic label according to claim 3 and having the protective printing layer on the innermost surface.   The plastic label according to any one of claims 1 to 3, which is a shrink label using a heat-shrinkable film as the label substrate.

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