label

Abstract

The present invention provides a label that can be attached to a substrate, which protects the display area, such as the printed surface, while allowing for easy information to be added. [Solution] A label having a base material and an adhesive layer, wherein the adhesive constituting the adhesive layer is a re-wettable adhesive, and the label having a display portion partially disposed on the side of the adhesive layer opposite to the base material.

Description

Technical Field

[0001] The present invention relates to labels.

Background Art

[0002] Labels have a display section for transmitting various types of information. As a method of displaying information, in addition to making the information visible from the surface side by printing or the like on the surface of the label, there are cases where the information is made visible from the adherend side (the back side of the label).

[0003] As a method of displaying information that can be viewed from the adherend side (the back side of the label), in Patent Document 1, by adopting a configuration of an opaque base material, an adhesive layer, a display section with a left-right reversed image, a semi-transparent or transparent base material, and an adhesive layer, the notation on the display section can be viewed from the back side attached to the adherend.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, since the printing surface (display section) is not arranged on the surface layer, the printing surface is protected from external abrasion and the like, but printing is performed on a semi-transparent or transparent base material, and an adhesive layer is arranged on the printing surface. In such a case, it is difficult to laterally impart information to the label after forming the adhesive label, and it lacks versatility.

[0006] Therefore, an object of the present invention is to provide a label that can easily impart information while protecting a display section such as a printing surface in a label that can be attached to an adherend.

Means for Solving the Problems

[0007] The present invention provides the following:

[0008] (1) A label having a base material and an adhesive layer, wherein the adhesive constituting the adhesive layer is a re-wettable adhesive, and the label having a display portion partially disposed on the side of the adhesive layer opposite to the base material.

[0009] (2) The label according to (1), wherein the re-wettable adhesive comprises at least one selected from the group consisting of polyvinyl alcohol-based adhesives, starch-based adhesives, cellulose-based adhesives, and polyvinyl acetate-based adhesives.

[0010] (3) The label described in (1) or (2), wherein the display unit contains variable information.

[0011] (4) The display section is a label formed by printing, as described in any of (1) to (3).

[0012] (5) A label according to any of (1) to (4), wherein the adhesive layer is partially exposed. [Effects of the Invention]

[0013] According to the label of the present invention, in a label that can be attached to an object, the display area can be protected, and even after the label is formed, the display area can be formed by general printing or other methods, making it easy to add information such as variable information. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1(A) is a schematic cross-sectional view of a label according to one embodiment of the present invention, and Figure 1(B) is a schematic cross-sectional view after the label has been attached to an object. [Figure 2] Figure 2(A) is a schematic cross-sectional view of a label according to another embodiment, and Figure 2(B) is a schematic cross-sectional view after the label has been attached to the substrate. [Figure 3] Figure 3 shows an example of the use of the label in the form shown in Figure 2. [Figure 4]Figure 4 shows another example of the use of the label in the form shown in Figure 2. [Modes for carrying out the invention]

[0015] The present invention relates to a label having a base material and an adhesive layer, wherein the adhesive constituting the adhesive layer is a re-wettable adhesive, and the label has a display portion on the side of the adhesive layer opposite to the base material.

[0016] Printing on adhesive or tacky layers that exhibit tackiness under normal conditions requires the use of special inks and equipment, thus lacking versatility. Furthermore, printing on tacky adhesive layers is often technically difficult. Moreover, if the adhesive layer surface is exposed during printing, printing methods that come into contact with the adhesive layer surface are unsuitable. Even with printing methods that do not come into contact with the adhesive layer surface, such as inkjet printing, problems can arise when using a roll-to-roll production system, such as the adhesive layer sticking to the rolls.

[0017] In this invention, the adhesive layer includes a re-wettable adhesive. The re-wettable adhesive exhibits tackiness upon application of water and is non-tacky under normal conditions. Therefore, the display area can be easily formed by conventional methods (e.g., printing). On the other hand, when attaching a label to an object, the adhesive layer exhibits tackiness upon application of water to the adhesive surface, making attachment to the object easy. In this specification, "printing" includes not only cases where a printing plate is used, but also cases where a printing plate is desired (so-called "printing").

[0018] Furthermore, since the re-moistened adhesive exhibits tackiness upon the application of water, it does not have tackiness when water is not applied. As a result, while a release liner is required before use for adhesive layers that are always tacky, the re-moistened adhesive layer does not require a release liner, thus reducing the environmental impact. Therefore, a label according to one embodiment of the present invention does not include a release liner. Moreover, since the adhesive layer does not require a release liner and is usually placed on the outermost layer of the label, it is easy to change the printing for each lot or print variable information.

[0019] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted. Also, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may be different from the actual ratios.

[0020] FIG. 1 is a cross-sectional view of a label according to an embodiment of the present invention. Note that the drawings are exaggerated for convenience of explanation, and the dimensional ratios of the respective components in the drawings may be different from the actual ones. As shown in FIG. 1(A), the label 10 is composed of a base material 11, an adhesive layer 12, and a display portion 13. The display portion 13 is partially formed on the adhesive layer 12. For this reason, the adhesive layer 12 is partially exposed on the back side, and when the exposed adhesive layer 12 comes into contact with water, the adhesive layer 12 exhibits tackiness, and the label 10 can be attached to the adherend 14 (FIG. 1(B)).

[0021] In the form of FIG. 1(A), the base material 11 is transparent, and after being attached to the adherend 14, the information of the display portion 13 is visible from the base material 11 side (front side) (FIG. 1(B)). Here, in order to be visible from the base material side, it is preferable that the haze of the base material is 25% or less (lower limit 0%). For the measurement of haze, the value measured in accordance with JIS K 7136:2000 using a haze meter (NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd.) is adopted. The adherend 14 may be transparent or opaque. When the adherend 14 is transparent, the display portion is also visible from the adhesive layer side (back side).

[0022] When forming the display portion by printing on the surface layer portion of the base material, in order to protect the printing from abrasion from the outside, etc., a transparent coat layer may be provided on the printing, or a laminate film may be attached. According to the configuration of the present invention, since the display portion is not arranged on the surface layer, the information of the display portion can be protected from abrasion, etc. without providing a transparent coat layer or a laminate film. Therefore, the number of manufacturing steps can be reduced, and since unnecessary members are not used, the environmental load is small.

[0023] Figure 2 is a cross-sectional view of a label according to another embodiment of the present invention. As shown in Figure 2(A), the label 20 consists of a base material 21, an adhesive layer 22, and a display portion 23. The display portion 23 is partially formed on the adhesive layer 22. Therefore, the adhesive layer 22 is partially exposed on the back side, and when this exposed adhesive layer 22 comes into contact with water, the adhesive layer 22 develops tackiness, allowing the label 20 to be attached to the adherend 25 (Figure 2(B)).

[0024] In the configuration shown in Figure 2(A), the substrate 21 is opaque, and the adherend 25 is transparent. After being attached to the transparent adherend 25, the information on the display section 23 is visible from the adherend 25 side (Figure 2(B)). If the display section 23 contains text, it may be mirrored text.

[0025] Examples of transparent substrates to which the adhesive can be applied include glass (e.g., window glass, glass bottles) and plastics (e.g., various containers, packaging materials, and sheet materials made from polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, acrylic, etc.).

[0026] Figure 3 shows an example of the use of the label in the form shown in Figure 2. In Figure 3, the label 20 from Figure 2 is affixed to a beverage bottle 15. In Figure 3(A), the beverage bottle 15 contains an opaque beverage 16, so the back of the label 20 is not visible. As the consumer drinks the beverage, the back of the label gradually becomes visible, and eventually the information on the label 20 (in the form shown in Figure 3(B), "Winner") becomes visible (Figure 3(B)).

[0027] Figure 4 shows another example of the use of the label in the form shown in Figure 2. In Figure 4, the label 20 is attached to an opaque substrate 25 (Figure 4(A)). Therefore, while the label is attached, the information on the label is not visible from the surface side of the label. When the label is peeled off the substrate, the contents of the label are exposed (Figure 4(B)), and once the label is completely removed from the substrate, the contents of the label become visible (Figure 4(C)).

[0028] In the configuration shown in Figure 4, the label may be in the form of a long tape. In this configuration, it can be used as a sealing tape for packaging.

[0029] The following describes the components that make up each label. In this specification, "X~Y" indicating a range means "X or more and Y or less". Unless otherwise specified, operations and measurements of physical properties are performed under room temperature (20~25°C) / relative humidity of 45~55%RH. In this specification, "(meth)acrylic acid" refers to "acrylic acid or methacrylic acid". In the following description, the labels of the present invention may be simply referred to as "labels". The concept of "label" includes things such as films, sheets, tapes, etc.

[0030] (base material) The substrate is not particularly limited and includes resin substrates; so-called synthetic paper made of resin; metal foils such as copper, aluminum, and stainless steel; composite sheet substrates made by laminating metal foil and plastic film; vapor-deposited foil substrates with aluminum, silica, etc.; nonwoven fabric substrates; or paper substrates. As resin substrates, for example, films made of at least one resin selected from polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyvinyl chloride, polystyrene, polyurethane, polycarbonate, polyamide, polyimide, polyetherimide, poly(meth)acrylic acid ester, polybutene, polybutadiene, polymethylpentene, acrylic urethane, ethylene vinyl acetate copolymer, ethylene(meth)acrylic acid copolymer, ethylene(meth)acrylic acid ester copolymer, ABS resin, ionomer resin, and various thermoplastic elastomers, or single or multiple laminated films selected from these can be used. The paper substrate is not particularly limited and includes, for example, high-quality paper, kraft paper, glassine paper, coated paper, art paper, cast-coated paper, impregnated paper, foamed paper, synthetic paper, thermal paper, dust-free paper, parchment paper, rayon paper, recycled paper, etc. The paper substrate may also be a laminate formed by stacking two or more layers of these materials.

[0031] As a base material, paper is preferable because it is easy to peel off during the cleaning process when recycling the object to which the label is applied after use. Furthermore, from the viewpoint of ease of use as a label, high-quality paper, glassine paper, coated paper, art paper, cast-coated paper, thermal paper, recycled paper, etc., are more preferable.

[0032] Various types of information, such as letters, numbers, symbols, and figures, may be recorded on the surface of the substrate (the side facing the adhesive layer).

[0033] Furthermore, the substrate may have a printable coating layer on its surface.

[0034] The thickness of the substrate is not particularly limited, but is preferably 10 μm to 200 μm, more preferably 20 μm to 150 μm, and even more preferably 30 μm to 100 μm. Such a thickness provides good handling during application.

[0035] (adhesive layer) The adhesive constituting the bonding layer is a re-wettable adhesive. Examples of materials for the re-wettable adhesive include protein-based materials such as gelatin, casein, albumin, and soy protein; hydrated carbon-based materials such as starch and dextrin; cellulose-based materials such as methylcellulose, hydroxyethylcellulose, ethylhydroxyethylcellulose, carboxymethylcellulose, and bissose; and water-soluble compounds such as gum arabic, tragacanth gum, sodium alginate, polyvinyl alcohol, and polyvinyl acetate. These materials may be used individually or in combination of two or more. In particular, from the viewpoint of tack performance, the re-wettable adhesive is preferably one that contains at least one selected from the group consisting of polyvinyl alcohol-based adhesives, starch-based adhesives, cellulose-based adhesives, and polyvinyl acetate-based adhesives, and more preferably a re-wettable adhesive that contains a polyvinyl alcohol-based adhesive.

[0036] Examples of polyvinyl alcohol used in polyvinyl alcohol-based adhesives include unmodified polyvinyl alcohol and modified polyvinyl alcohol.

[0037] Examples of modified polyvinyl alcohols include α-olefin-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, anionic-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, and mercapto-modified polyvinyl alcohol.

[0038] The adhesive strength of the adhesive layer depends, for example, on the degree of polymerization of the polyvinyl alcohol constituting the re-wettable adhesive, with the degree of polymerization of the polyvinyl alcohol preferably being 300 to 5000, more preferably 350 to 4900, and even more preferably 400 to 4800.

[0039] This makes it possible to improve the solubility of polyvinyl alcohol in water, allowing for a more favorable formation of the adhesive layer, and also improves the adhesive strength when water is applied.

[0040] In this specification, "degree of polymerization of polyvinyl alcohol" refers to the value measured by a method conforming to the "average degree of polymerization" described in JIS K 6726:1994.

[0041] Even if the degree of polymerization of polyvinyl alcohol is within the aforementioned range, the adhesion of the adhesive layer can be adjusted by varying the degree of polymerization.

[0042] For example, if the degree of polymerization of polyvinyl alcohol is in a relatively low range, the polyvinyl alcohol becomes more soluble in water, which can improve the initial adhesive strength of the adhesive layer, in other words, the adhesive strength after water is applied to the adhesive layer to induce tackiness and before it dries.

[0043] Furthermore, if the degree of polymerization of polyvinyl alcohol is in a relatively high range within the aforementioned range, the adhesive strength of the adhesive layer after drying, in other words, the adhesive strength when the adhesive layer is given water to develop tackiness, attached to the adherend, and then dried to form a film, will be high.

[0044] This allows for better final adhesive strength.

[0045] Furthermore, the degree of polymerization of polyvinyl alcohol can be determined according to the adhesive properties that are important in the adhesive layer, such as the initial adhesive strength after application to the substrate or the adhesive strength after drying.

[0046] Furthermore, considering the balance between the two above, it is also preferable to combine polyvinyl alcohols with high and low degrees of polymerization. Specifically, polyvinyl alcohol A, which has a degree of polymerization of 300 to 800, may be combined with polyvinyl alcohol B, which has a degree of polymerization of 2000 to 5000. The degree of polymerization of polyvinyl alcohol A is more preferably 350 to 700, and even more preferably 400 to 600. The degree of polymerization of polyvinyl alcohol B is more preferably 2300 to 4900, and even more preferably 4200 to 4800. The mixing ratio of polyvinyl alcohol A to polyvinyl alcohol B is preferably 30:70 to 70:30 by mass, more preferably 35:65 to 65:35, and even more preferably 40:60 to 60:40.

[0047] The degree of saponification of the polyvinyl alcohol is preferably 70 mol% to 90 mol%, more preferably 75 mol% to 90 mol%, and even more preferably 80 mol% to 90 mol%. This makes it possible to improve the tackiness that develops when water is applied to the adhesive layer.

[0048] In this specification, "degree of saponification of polyvinyl alcohol" refers to the value measured by a method conforming to the "degree of saponification" described in JIS K 6726:1994.

[0049] Examples of starches used in starch-based adhesives include cornstarch, wheat flour, sweet potato starch, potato starch, and tapioca. Note that this includes modified starch.

[0050] Polyvinyl acetate adhesives consist of polymers containing vinyl acetate as monomer units, and examples of constituent materials include polyvinyl acetate and ethylene-vinyl acetate copolymers.

[0051] Examples of materials that make up cellulose-based adhesives include methylcellulose, hydroxyethylcellulose, ethylhydroxyethylcellulose, carboxymethylcellulose, and biscellulose.

[0052] The adhesive layer may contain other components. Examples of other components include fillers, softeners, heat and light stabilizers, antioxidants, and crosslinking agents.

[0053] The thickness of the adhesive layer is, for example, 3 to 30 μm.

[0054] The adhesive layer can be formed, for example, by mixing the above components with a solvent (e.g., water) to prepare an adhesive layer-forming composition, and then coating the composition onto a substrate. The solid content of the adhesive layer-forming composition is, for example, 5 to 60% by mass.

[0055] Methods for applying the adhesive layer-forming composition include, for example, the roll coating method, bar coating method, knife coating method, roll-knife coating method, blade coating method, die coating method, and gravure coating method.

[0056] After coating, the adhesive layer-forming composition is dried to form an adhesive layer. This removes the moisture contained in the coated adhesive layer-forming composition, and the adhesive layer is formed. Drying can be done, for example, by natural drying or air drying, but it is preferable to dry it by heating. The drying temperature is preferably 60°C to 100°C, and more preferably 70°C to 90°C.

[0057] [Display] The display unit is imprinted with various types of information, such as characters, numbers, symbols, and graphics (e.g., a company logo). While there are no particular limitations on how the display unit is formed, it is preferably formed by printing because it allows for the mass production of a fixed pattern and other designs, and also allows for the easy addition of variable information. Specifically, it can be formed by flexographic printing, offset printing, letterpress printing, gravure printing, screen printing, etc., which are suitable for mass production of a fixed pattern. On the other hand, thermal transfer printing, inkjet printing, electrophotography (electrostatic) printing, etc., are suitable for imprinting variable information, such as serial numbers.

[0058] In the present invention, since the re-wet adhesive layer is placed on the surface, it is easy to form a display area by printing or other means. Therefore, even if the display area contains variable information, the information can be displayed easily. For this reason, a preferred embodiment of the present invention is one in which the display area contains variable information. Examples of variable information include lot number, serial number, manufacturing date, barcode, two-dimensional code, lottery result (winner, loser), address, name, telephone number, etc.

[0059] The ink used to form the display area, for example by printing, is not particularly limited and includes, for example, oil-based ink, latex ink, and light-curing ink (ultraviolet-curing ink, electron beam-curing ink).

[0060] The display portion is partially provided on the adhesive layer in order to leave an exposed adhesive layer for adhesion to the substrate (the adhesive layer is partially exposed). The area of ​​the display portion is, for example, 60% or less of the area of ​​the adhesive layer before the display portion is formed, but may also be 30% or less, 1 to 60%, or 3 to 30%.

[0061] [How to use the label] The label according to the present invention is attached to an object by the adhesive layer after water is applied to the adhesive layer to give it tackiness. The water applied to the adhesive layer is not particularly limited, but for example, tap water, deionized water, etc. can be used, and liquids containing water can also be used.

[0062] There are no particular limitations on the method of applying water to the adhesive layer, but examples include using a spray bottle, brush, sponge, sponge roller, etc.

[0063] Although labels according to embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the invention. [Explanation of symbols]

[0064] 10, 20 labels, 11, 21 base material, 12, 22 adhesive layer, 13, 23 display section, 14 Opaque adherend, 15 Transparent substrate (beverage bottle), 16 opaque drinks, 25 Transparent adherend.

Claims

1. Having a base material and an adhesive layer, The adhesive constituting the aforementioned adhesive layer is a re-wettable adhesive. A label having a display portion partially positioned on the side of the adhesive layer opposite to the substrate.

2. The label according to claim 1, wherein the re-wettable adhesive comprises at least one selected from the group consisting of polyvinyl alcohol-based adhesives, starch-based adhesives, cellulose-based adhesives, and polyvinyl acetate-based adhesives.

3. The label according to claim 1 or 2, wherein the display unit contains variable information.

4. The label according to claim 1 or 2, wherein the display portion is formed by printing.

5. The label according to claim 1 or 2, wherein the adhesive layer is partially exposed.

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