Adhesive label and method for manufacturing the same

Abstract

To provide an adhesive label in which an adhesive layer is formed by partial application and the occurrence of curling and tunneling can be suppressed. [Solution] An adhesive label 1 in which a base layer 10, an adhesive layer 20, and a release liner 30 are laminated in this order, the adhesive layer being of a hot melt type and comprising, when viewed from the front, a formation region 21 where the adhesive layer is formed and a non-formation region 22 where the adhesive layer is not formed, and the release liner comprising a base paper and a release agent layer.

Description

[Technical Field]

[0001] The present invention relates to an adhesive label and a method for manufacturing an adhesive label. [Background technology]

[0002] Generally, a pressure-sensitive adhesive label is constructed by laminating a substrate layer, a pressure-sensitive adhesive layer, and a release liner in this order. When the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is an emulsion-based pressure-sensitive adhesive or a solvent-based pressure-sensitive adhesive, a pressure-sensitive adhesive composition is applied onto a release liner, followed by a drying step to form the pressure-sensitive adhesive layer, and then the substrate is attached to the pressure-sensitive adhesive layer (for example, Patent Document 1 listed below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2024-081313 Summary of the Invention [Problem to be solved by the invention]

[0004] When the adhesive layer is made of an emulsion-based adhesive or a solvent-based adhesive, a drying process at high temperatures is required. However, when the release liner is made of paper (i.e., release paper), the drying process unintentionally reduces the moisture content of not only the adhesive layer but also the release paper.

[0005] On the other hand, paper is generally made from pulp fibers. The pulp fibers contained in paper absorb or release moisture depending on the humidity of the storage or usage environment, and as this occurs, the fibers expand or contract, causing the paper to stretch or shrink.

[0006] To compensate for the loss of moisture in the release paper, a process of adding moisture to the release paper is carried out after the drying process, but there is a possibility that sufficient moisture may not be added to the release paper. In this case, for example, when the adhesive label is stored, the release paper may absorb moisture and stretch, causing curling (deformation into a curved shape) or tunneling (separation of the release paper and the adhesive).

[0007] On the other hand, so-called partial coating, in which the adhesive layer is formed to have a formed region where the adhesive layer is formed and a non-formed region where the adhesive layer is not formed, is preferred. The reasons for this include that the non-formed region can be conveniently used as a handle when peeling off the release liner, that the amount of adhesive composition used can be reduced, leading to cost savings, and that leakage of the adhesive layer to the outside can be suppressed when pressure is applied to the adhesive label.

[0008] However, when partial application of the adhesive layer is adopted, in the formation region where the adhesive layer is present, the base material layer and the release paper are restrained by the adhesive and the release paper stretches, making the above-mentioned curling more likely to occur, while in the non-formation region where the adhesive layer is not present, the base material layer and the release paper can move freely between them, making tunneling more likely to occur. Such curling and tunneling are undesirable because they reduce workability during the production process of adhesive labels.

[0009] The present invention has been made to solve the above-mentioned problems, and has an object to provide an adhesive label and a method for manufacturing an adhesive label that can suppress the occurrence of curling and tunneling even when an adhesive layer is formed by partial application. [Means for solving the problem]

[0010] The above object of the present invention can be achieved by the following means.

[0011] (1) An adhesive label having a base layer, an adhesive layer, and a release liner laminated in this order, The pressure-sensitive adhesive layer is a hot melt type, When viewed from the front, the adhesive sheet has a formation region where the pressure-sensitive adhesive layer is formed and a non-formation region where the pressure-sensitive adhesive layer is not formed, The release liner is an adhesive label comprising a base paper and a release agent layer.

[0012] (2) The adhesive label according to (1), wherein the thickness of the base paper is 90 μm or less.

[0013] (3) The basis weight of the base paper is 95 g / m 2 An adhesive label according to (1) or (2), which is:

[0014] (4) The pressure-sensitive adhesive label according to any one of (1) to (3), wherein the substrate layer is a paper substrate.

[0015] (5) A method for producing a pressure-sensitive adhesive label in which a base layer, a hot-melt type pressure-sensitive adhesive layer, a base paper, and a release liner having a release agent layer are laminated in this order, a method for manufacturing an adhesive label, wherein when forming the adhesive layer on the release liner, the adhesive layer is formed so as to have, in a front view, a formation region where the adhesive layer is to be formed and a non-formation region where the adhesive layer is not to be formed. [Effects of the Invention]

[0016] According to the above-mentioned pressure-sensitive adhesive label, since the pressure-sensitive adhesive layer is of a hot-melt type, a drying process is not required when forming the pressure-sensitive adhesive layer on the release paper. Therefore, a decrease in the moisture content of the release paper is suppressed. Therefore, for example, absorption of moisture during storage of the pressure-sensitive adhesive label is suppressed, and the occurrence of curling and tunneling can be suppressed. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a front cross-sectional view showing an adhesive label according to an embodiment of the present invention. [Figure 2]1 is a front cross-sectional view showing a coating device that coats a pressure-sensitive adhesive composition for a pressure-sensitive adhesive label according to the present embodiment. [Figure 3] FIG. 2 is a schematic perspective view of a coating device that coats the adhesive composition of the adhesive label according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicate explanations will be omitted. Furthermore, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0019] The configuration of an adhesive label 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing an adhesive label 1 according to this embodiment.

[0020] The adhesive label 1 according to this embodiment is not particularly limited, but may be a delivery slip label with the address and item information printed on it, which is affixed to cardboard boxes or the like when a package is transported to a destination by a courier or other means.

[0021] The adhesive strength of the adhesive label 1 is preferably 2 N / 25 mm or more, more preferably 4 N / 25 mm or more, and even more preferably 5 N / 25 mm or more. When the adhesive strength of the adhesive label 1 is equal to or greater than the above-mentioned lower limit, adhesion to the adherend is ensured. The adhesive label 1 needs to be attached to the adherend for a long period of time, and therefore requires a certain degree of adhesiveness. The upper limit of the adhesive strength is not particularly limited, but is, for example, 15 N / 25 mm or less.

[0022] As shown in Fig. 1, the adhesive label 1 has a base layer 10, an adhesive layer 20, and a release liner 30. In Fig. 1, the adhesive label 1 is a laminate having the base layer 10, the adhesive layer 20, and the release liner 30 in this order, but other intermediate layers may be present on the base layer 10 and / or between the base layer 10 and the adhesive layer 20, as long as the adhesive layer 20 is exposed when the label is attached to an adherend.

[0023] The base material layer 10 imparts functions according to the application of the pressure-sensitive adhesive label 1, such as conformability to the adherend and scratch resistance. The thickness of the base material layer 10 is not particularly limited, but is, for example, 40 μm or more and 120 μm or less.

[0024] The base material layer 10 is not particularly limited, but examples thereof include paper base materials such as kraft paper and Japanese paper, resin base materials, and synthetic paper.

[0025] Examples of resins constituting the resin substrate include olefin-based resins containing α-olefins as monomer components, such as polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer (EVA); polyester-based resins, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyvinyl chloride (PVC); vinyl acetate-based resins; polycarbonate (PC); acrylic resins; and polyurethanes. These resins may be used alone or in combination. Among these, polyvinyl chloride, acrylic resins, and polyurethanes are preferred as resins constituting the resin substrate from the viewpoints of weather resistance and flexibility.

[0026] Examples of synthetic paper include polyester film and polypropylene film having fine voids.

[0027] The substrate layer 10 may be transparent or opaque.

[0028] The substrate layer 10 may be colored or colorless. If it is colored, any colorant can be used. The colored substrate can be produced by blending a colorant with a raw resin, melt-kneading the mixture, and forming it into a film. Alternatively, it can be produced by a cast film production method in which the mixture is cast onto a process film and dried to form the film.

[0029] The base layer 10 may contain various additives such as ultraviolet absorbers, plasticizers, and heat stabilizers. Examples of ultraviolet absorbers include salicylic acid-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and benzotriazole-based ultraviolet absorbers. Examples of plasticizers include phosphoric acid-based plasticizers, phthalic acid-based plasticizers, adipic acid-based plasticizers, and polyester-based plasticizers. Examples of heat stabilizers include lead salt-based heat stabilizers, metal soap-based heat stabilizers, and organotin compound-based heat stabilizers.

[0030] When the pressure-sensitive adhesive layer 20 is provided on one side of the base layer 10, one side of the base layer 10 may be subjected to a surface treatment in order to improve adhesion to the pressure-sensitive adhesive layer 20. Examples of surface treatments include corona discharge treatment, plasma treatment, and primer treatment.

[0031] When a paper substrate is used as the substrate layer 10, a paper substrate that has not undergone a drying process is bonded to a release paper that has undergone a drying process, and curling and tunneling are likely to occur due to the difference in elongation between them. On the other hand, when a synthetic paper or resin substrate is used as the substrate layer 10, a non-stretchable substrate is bonded to a stretchable release paper, and curling and tunneling are likely to occur. However, according to the present invention, the pressure-sensitive adhesive label 1 can be manufactured without performing a drying process, and therefore curling and tunneling can be suppressed regardless of whether the substrate is a paper substrate, synthetic paper, or resin substrate.

[0032] The adhesive layer 20 is a hot-melt adhesive layer. A hot-melt adhesive is an adhesive that melts when heated and returns to its original solid state when cooled, and is a material obtained by kneading a main raw material with additives. Specific examples of the main raw material include various materials such as acrylic, rubber, urethane, ester, and polyamide materials. More specific examples include polyolefins, ethylene-vinyl acetate copolymers, styrene-butadiene-styrene block copolymers, and styrene-isoprene-styrene block copolymers. Specific examples of additives include tackifying resins such as rosin esters and alicyclic hydrocarbons, and plasticizers such as naphthenic oil.

[0033] 1, in a front cross-sectional view, the adhesive layer 20 has a formation region 21 where the adhesive layer 20 is formed, and a non-formation region 22 where the adhesive layer 20 is not formed. In other words, the adhesive layer 20 is formed so as to be a so-called partial coating.

[0034] By forming the adhesive layer 20 by partial application in this manner, the non-formed area can be used as a handle when peeling off the release liner 30, the amount of adhesive composition used can be reduced, leading to cost savings, and the adhesive layer 20 can be prevented from leaking out when pressure is applied to the adhesive label 1.

[0035] The thickness of the adhesive layer 20 is not particularly limited, but is preferably in the range of 10 μm to 50 μm from the viewpoint of adhesiveness and thinning.

[0036] The release liner 30 is a member that has the function of protecting the pressure-sensitive adhesive layer 20 and preventing a decrease in adhesiveness. The release liner 30 is peeled off from the pressure-sensitive adhesive label 1 when the label is to be stuck to an adherend.

[0037] The release liner 30 comprises a base paper and a release agent layer. The release agent layer is formed by applying a release agent such as silicone resin. A coating layer may be formed on at least one surface of the base paper. The coating layer is made of, for example, polyethylene. This configuration can prevent moisture from penetrating the base paper and causing curling or tunneling in the adhesive label 1. Glassine paper is preferred as the base paper, but high-quality paper, clay-coated paper, polyethylene-laminated paper, etc. may also be used.

[0038] The coating layer may contain other additives such as pigments, pigment dispersants, defoamers, antifoaming agents, viscosity modifiers, lubricants, water-resistant agents, water retention agents, and coloring materials.

[0039] The thickness of the base paper is preferably 40 μm or more and 90 μm or less. If the thickness of the base paper is made thinner than that of ordinary base paper, it becomes more susceptible to deformation, and curling and tunneling are more likely to occur. However, according to the present invention, even when the base paper is thin, it is possible to manufacture the pressure-sensitive adhesive label 1 without carrying out a drying process, and therefore the occurrence of curling and tunneling can be suppressed.

[0040] The basis weight of the base paper is 35 g / m 2 More than 95g / m 2 It is preferable that the basis weight of the base paper is within this range. If the basis weight of the base paper is within this range, the stiffness of the paper will decrease, making curling and tunneling more likely to occur. However, according to the present invention, even if the basis weight of the base paper is within the above range, it is possible to manufacture the pressure-sensitive adhesive label 1 without carrying out a drying step, and therefore it is possible to suppress the occurrence of curling and tunneling.

[0041] Next, with reference to Figs. 2 and 3, the configuration of a coating device 100 that coats a release liner 30 with a hot-melt pressure-sensitive adhesive composition will be described.

[0042] As shown in Figures 2 and 3, the coating device 100 has a die upper plate 110, a die lower plate 120, a manifold 130 formed between the die upper plate 110 and the die lower plate 120, and a shim plate 140 arranged between the die upper plate 110 and the die lower plate 120.

[0043] In the coating device 100 configured in this manner, the adhesive composition supplied from the injection port 121 provided in the die lower plate 120 is spread in the width direction in the manifold 130, and then extruded from the slot portion 150 formed between the shim plates 140, and is partially coated on the release liner 30 so as to form the formation region 21 and the non-formation region 22, thereby forming the adhesive layer 20. In the method for producing the adhesive label 1 according to this embodiment, the adhesive layer 20 is of the hot melt type, and therefore does not require a high-temperature drying step, which is a step required when the adhesive is an emulsion-based adhesive or a solvent-based adhesive.

[0044] As described above, the adhesive label 1 according to the present embodiment is formed by laminating, in this order, the base material layer 10, the adhesive layer 20, and the release liner 30. The adhesive layer 20 is of a hot melt type, and, in a front view, comprises a formation region 21 where the adhesive layer 20 is formed and a non-formation region 22 where no adhesive layer is formed, and the release liner 30 comprises a base paper and a release agent layer.

[0045] For example, when the adhesive constituting the adhesive layer is an emulsion-based adhesive or a solvent-based adhesive, the adhesive composition is applied to a release liner, followed by a drying process to form an adhesive layer, and then a substrate is laminated to the adhesive layer. However, in the drying process, not only the moisture in the adhesive layer but also the moisture in the release liner is unintentionally reduced. To compensate for this loss of moisture in the release liner, a process of adding moisture to the release liner is performed after the drying process, but there is a possibility that sufficient moisture cannot be added to the release liner. In this case, for example, during storage of the adhesive label, the release liner may absorb moisture, causing curling, in which the release liner is deformed into a curved shape, or tunneling, in which a tunnel-like separation occurs between the release liner and the adhesive.

[0046] In contrast, according to the adhesive label 1 according to the present embodiment, the adhesive layer is of a hot melt type, and therefore no drying step is required when forming the adhesive layer 20 on the release liner 30. This prevents a decrease in the moisture content of the release liner 30. Therefore, for example, moisture absorption during storage of the adhesive label is suppressed, and the occurrence of curling or tunneling can be suppressed.

[0047] The adhesive label 1 according to the present invention has been described above through the embodiments, but the present invention is not limited to the above-described embodiments and can be modified in various ways within the scope of the claims. [Explanation of symbols]

[0048] 1 adhesive label, 10 base material layer, 20 adhesive layer, 21 forming area, 22 non-formed area, 30 release liners.

Claims

1. An adhesive label having a base layer, an adhesive layer, and a release liner laminated in this order, The pressure-sensitive adhesive layer is a hot melt type, When viewed from the front, the adhesive sheet has a formation region where the pressure-sensitive adhesive layer is formed and a non-formation region where the pressure-sensitive adhesive layer is not formed, The release liner is an adhesive label comprising a base paper and a release agent layer.

2. The adhesive label according to claim 1 , wherein the base paper has a thickness of 90 μm or less.

3. The basis weight of the base paper is 95 g / m ２ The adhesive label according to claim 1 or 2, wherein:

4. The adhesive label according to claim 1 or 2, wherein the substrate layer is a paper substrate.

5. A method for producing a pressure-sensitive adhesive label in which a base layer, a hot-melt type pressure-sensitive adhesive layer, a base paper, and a release liner having a release agent layer are laminated in this order, a method for manufacturing an adhesive label, wherein when forming the adhesive layer on the release liner, the adhesive layer is formed so as to have, in a front view, a formation region where the adhesive layer is to be formed and a non-formation region where the adhesive layer is not to be formed.

Images