JP2024143068A - Peel detection label - Google Patents

Abstract

[Problem] There is a demand for a peel detection label that can be suitably used in various environments and applications. [Solution] A peel detection label 101 consisting of a laminate having, in this order, a support 1, a pattern layer 2 formed on a portion of the surface of the support, and an adhesive laminate 10 having at least an intermediate layer 3 and an adhesive layer 4, wherein the support has at least one paper base layer, and the peel detection label has a concealment rate of 75.0% or less as measured in accordance with JIS K5600-4-1:1999. [Selected Figure] Figure 1

Description

The present invention relates to peel detection labels.

Peel detection labels are used in applications that require safety and high security to check whether a package has been opened once. For example, peel detection labels are used on packages of medicines and foods, containers filled with dangerous goods such as chemical bottles and fuel tanks, letters, and cosmetic boxes to prevent unauthorized opening, and to prevent unauthorized use of identification photos on identification documents such as passports.
For example, Patent Document 1 discloses a tamper-evident label or sheet that is characterized by comprising a polystyrene film having a thickness of 10 μm or more and 40 μm or less, and a heat-resistant adhesive layer having an adhesive strength of 15 N/25 mm or more at 80° C. as specified in JIS Z 0237 laminated on one surface of the polystyrene film.

JP 2010-281948 A

In recent years, there has been an increasing demand for peel detection labels that do not use plastic materials in order to reduce the impact on the environment.
Under these circumstances, there is a demand for peeling detection labels that reduce the impact on the environment while allowing easy visual confirmation of whether peeling has occurred.

The present invention provides a peel detection label comprising a laminate having, in this order, a support having at least one paper base layer, a pattern layer formed on a portion of the surface of the support, and an adhesive laminate having at least an intermediate layer (C) and an adhesive layer (Z), the hiding rate of which is adjusted to a predetermined range.
Specific aspects of the present invention are as follows [1] to [9].
[1] A peel detection label comprising a laminate having, in this order, a support, a pattern layer formed on a part of a surface of the support, and an adhesive laminate having at least an intermediate layer (C) and an adhesive layer (Z),
The support has at least one paper base layer,
The peel detection label has a concealment rate of 75.0% or less as measured in accordance with JIS K5600-4-1:1999.
[2] The peel detection label described in [1] above, wherein the breaking strength of the support at 23°C is 30 to 500 MPa.
[3] A peel detection label described in [1] or [2] above, wherein the support has a tensile modulus at 23°C of less than 50 MPa or more than 1000 MPa.
[4] The peel detection label according to any one of [1] to [3] above, wherein the thickness of the support is 10 to 150 μm.
[5] The peel detection label described in any one of [1] to [4] above, wherein the degree of beating of the support measured in accordance with JIS P8121-1:2012 is 20 mL or more.
[6] A peel detection label described in any one of [1] to [5] above, wherein the haze of the peel detection label is 40% or more.
[7] A peel detection label according to any one of the above [1] to [6], wherein the peel detection label has a total light transmittance (Tt) of 30% or more.
[8] A peel detection label described in any one of [1] to [7] above, wherein the difference (|Td - Tt|) between the total light transmittance (Tt) and the diffuse transmittance (Td) of the peel detection label is 0.10 to 30.0%.
[9] The peel detection label described in any one of [1] to [8] above, wherein the basis weight of the support is 20 to 120 g/ ^m2 .
[10] A peel detection label according to any one of the above [1] to [9], in which, after the adhesive layer (Z) of the peel detection label is affixed to an adherend, when it is peeled off from the adherend, interfacial peeling occurs between the support and the pattern layer, making it possible to visually detect whether or not the peel detection label has peeled off.

A preferred embodiment of the peeling detection label of the present invention is a peeling detection label that reduces the impact on the environment while making it easy to visually check whether peeling has occurred.

1 is a schematic cross-sectional view of a peel detection label 101, showing an example of the configuration of a peel detection label of the present invention. 1 is a schematic cross-sectional view of a peel detection label 102, showing an example of the configuration of a peel detection label of the present invention. 1 is a schematic cross-sectional view of a peel detection label 103, showing an example of the configuration of a peel detection label of the present invention. Fig. 2 is a schematic cross-sectional view showing a state in the middle of peeling a peel detection label 102, which is one example of the configuration of the peel detection label of the present invention, from an adherend 40. Fig. 3 is a schematic cross-sectional view of a sheet, showing one example of the configuration of the peel detection label of one embodiment of the present invention.

In this specification, the determination of whether a resin in question belongs to the "adhesive resin" or the "non-adhesive resin" is made based on the following steps (1) to (4).
Procedure (1): An adhesive sheet is prepared by providing a 20 μm thick resin layer formed only from the target resin on a 50 μm thick polyethylene terephthalate (PET) film, and the adhesive sheet is then cut to a size of 300 mm length x 25 mm width to prepare a test piece.
Procedure (2): In an environment of 23°C and relative humidity of 50%, the surface of the exposed side of the resin layer of the test piece of (1) above is attached to a stainless steel plate (SUS304, polished #360), and left to stand in the same environment for 24 hours.
Procedure (3): After standing, the adhesive strength is measured at a tension speed of 300 mm/min by a 180° peeling method in accordance with JIS Z0237:2000 in an environment of 23° C. and relative humidity of 50%.
Step (4): If the adhesive strength measured in step (3) is 0.1 N/25 mm or more, the resin is judged to be an "adhesive resin." On the other hand, if the adhesive strength measured is less than 0.1 N/25 mm, the resin is judged to be a "non-adhesive resin."

As used herein, the term "active ingredient" refers to the components contained in the target composition excluding diluent solvents.
In this specification, for example, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid,""(meth)acrylate" refers to both "acrylate" and "methacrylate," and similar terms.

In this specification, the mass average molecular weight (Mw) is a value calculated as standard polystyrene measured by gel permeation chromatography (GPC), and specifically, is a value measured based on the method described in the examples.
In this specification, the thickness of each layer means a value measured using an apparatus conforming to any one of JIS K6783:1994, JIS Z1702:1994, and JIS Z1709:1995, and specifically, a value measured based on the method described in the examples.
The thickness of each layer constituting the adhesive laminate may be measured in the same manner as the total thickness of the adhesive layer laminate described above, and may be measured, for example, by the method described in the Examples. A cross section of the adhesive laminate cut in the thickness direction may be observed with a scanning electron microscope to measure the thickness ratio of each layer, and the thickness ratio may be calculated from the total thickness of the adhesive laminate measured by the method described above.

In addition, for the numerical ranges (e.g., ranges of content, etc.) described in this specification, the lower limit and upper limit described in stages can be combined independently. For example, from the description "preferably 10 to 90, more preferably 30 to 60", the "preferable lower limit (10)" and the "more preferable upper limit (60)" can be combined to form "10 to 60". Similarly, from the description "preferably 10 or more, more preferably 30 or more, and preferably 90 or less, more preferably 60 or less", the preferred range can be selected as "10 to 60", or the range "60 or less". In addition, when numerical values are connected with "-" to express a numerical range such as content, the description "X to Y" means "X or more (X or more than X) Y or less (Y or less than Y)".

[Configuration of peel detection label]
A peel detection label according to one embodiment of the present invention is a peel detection label comprising a laminate having, in this order, a support, a pattern layer formed on a portion of the surface of the support, and an adhesive laminate having at least an intermediate layer (C) and an adhesive layer (Z).
Below, preferred examples of peel detection labels according to embodiments of the present invention are described using Figures 1 to 4. However, the peel detection labels of the present invention are not limited to the following examples as long as the effects of the present invention are manifested.

FIG. 1 is a schematic cross-sectional view of a peel detection label 101, showing an example of the configuration of the peel detection label of the present invention.
For example, a peel detection label shown as one embodiment of the present invention may be one in which a support 1, a pattern layer 2, and an adhesive laminate 10 are laminated in this order, such as a peel detection label 101 shown in Fig. 1. The adhesive laminate 10 shown in Fig. 1 is one in which an intermediate layer (C) (hereinafter also referred to as "layer (C)") 3 and an adhesive layer (Z) (hereinafter also referred to as "layer (Z)") 4 are laminated in this order from the pattern layer 2 side.
In the case of an embodiment such as the peel detection label 101 shown in Figure 1, the layer (C) 3 may be in contact with the surface 1a of the support 1 on the side on which the pattern layer 2 is formed and the pattern layer 2, and it is preferable that the layer (C) 3 is in contact with the surface 1a of the support 1 on which the pattern layer 2 is formed and the surface 2a of the pattern layer 2 opposite the support 1 side. It is more preferable that the layer (C) 3 is in contact with the surface 1a of the support 1 on which the pattern layer 2 is formed and covers all surfaces of the pattern layer 2 other than the surface in contact with the surface 1a of the support 1, as in the peel detection label 101 shown in Figure 1, and it is even more preferable that the layer (C) 3 and the layer (Z) 4 are directly laminated in this order in the adhesive laminate 10.
Here, the aforementioned “direct lamination” refers to a configuration in which, for example, in the case of the peel detection label 101 shown in Figure 1, the two layers are in direct contact with each other, with no other layers between layer (C) 3 and layer (Z) 4.
As described later, in the peel detection label according to one embodiment of the present invention, when the peel detection label is peeled off from the adherend, a tensile stress acts on the support and the intermediate layer (C), causing peeling at the interface between the pattern layer and the layer (preferably the support) adjacent to the pattern layer, making it possible to detect the peel detection label. The peel detection label is a peel detection label that does not leave any adhesive residue on the adherend.
Therefore, when the peel detection label is peeled off from the substrate, the intermediate layer (C) is capable of following the substrate without peeling at the interface between the pattern layer and the layer adjacent to the pattern layer (preferably the substrate) without peeling at the interface between layer (C) and the substrate, and at the same time, it is a layer that has the role of preventing adhesive residue on the substrate by peeling off from the substrate while holding layer (Z) in place without peeling at the interface between layer (C) and layer (Z).

FIG. 2 is a schematic cross-sectional view of a peel detection label 102, showing a preferred example of the configuration of the peel detection label of the present invention.
For example, a peel detection label shown as a suitable example of the present invention may be one in which a support 1, a pattern layer 2, and an adhesive laminate 11 are laminated in this order, such as a peel detection label 102 shown in Fig. 2. The adhesive laminate 11 shown in Fig. 2 is one in which, from the pattern layer 2 side, a coating layer (X) (hereinafter also referred to as "layer (X)") 5, a base layer (Y) (hereinafter also referred to as "layer (Y)") 6, and a layer (Z) 4 are laminated in this order.
In the case of an embodiment such as the peel detection label 102 shown in Figure 2, the layer (X) 5 may be in contact with the surface 1a of the support 1 on the side on which the pattern layer 2 is formed and the pattern layer 2, and it is preferable that the layer (X) 5 is in contact with the surface 1a of the support 1 on which the pattern layer 2 is formed and the surface 2a of the pattern layer 2 opposite the support 1 side. It is more preferable that the layer (X) 5 is in contact with the surface 1a of the support 1 on which the pattern layer 2 is formed and covers all surfaces of the pattern layer 2 other than the surface in contact with the surface 1a of the support 1, as in the peel detection label 102 shown in Figure 2, and it is even more preferable that the layer (X) 5, layer (Y) 6 and layer (Z) 4 are directly laminated in this order in the adhesive laminate 11.
2, "direct lamination" refers to a configuration in which the two layers are in direct contact with each other without any other layer between layer (X) 5 and layer (Y) 6, and the two layers are in direct contact with each other without any other layer between layer (Y) 6 and layer (Z) 4. In other words, it refers to a lamination state in which three layers are in direct contact with each other without any other layer between layer (X) 5 and layer (Y) 6, and between layer (Y) 6 and layer (Z) 4.

FIG. 3 is a schematic cross-sectional view of a peel detection label 103, showing a preferred example of the configuration of the peel detection label of the present invention.
For example, a peel detection label shown as a suitable example of the present invention may be one in which a support 1, a pattern layer 2, and an adhesive laminate 12 are laminated in this order, such as a peel detection label 103 shown in Fig. 3. The adhesive laminate 12 shown in Fig. 3 is one in which, from the pattern layer 2 side, a covering layer (X) 5 composed of a first covering layer (X1) (hereinafter also referred to as "layer (X1)") 7 and a second covering layer (X2) (hereinafter also referred to as "layer (X2)") 8, a base layer (Y) 6, and an adhesive layer (Z) 4 are laminated in this order.
In the layer (X) 5, the layer (X1) 7 and the layer (X2) 8 constituting the layer (X) 5 are present in the order of the layer (X1) 7 and the layer (X2) 8 from the layer closest to the support.
In the case of an embodiment such as the peel detection label 103 shown in FIG. 3, the layer (X1) 7 of the layer (X) 5 may be in contact with the surface 1a of the support 1 on the side on which the pattern layer 2 is formed and the pattern layer 2, and it is preferable that the layer (X1) 7 is in contact with the surface 1a of the support 1 on the side on which the pattern layer 2 is formed and the surface 2a of the pattern layer 2 opposite the support 1 side. It is more preferable that the layer (X1) 7 is in contact with the surface 1a of the support 1 on the side on which the pattern layer 2 is formed and covers all surfaces of the pattern layer 2 other than the surface in contact with the surface 1a of the support 1, as in the peel detection label 103 shown in FIG. 3, and it is even more preferable that the layer (X1) 7, the layer (X2) 8, the layer (Y) 6 and the layer (Z) 4 are directly laminated in this order in the adhesive laminate 12.

In each of the peel detection labels 101, 102, and 103 of the embodiments shown in Figures 1 to 3, the attachment surface of the layer (Z) 4 is the attachment surface 10a, 11a, and 12a of the adhesive laminate, respectively, and the label is attached to an adherend via this attachment surface.
In addition, a release material may be further laminated on the attachment surfaces 10a, 11a, and 12a.
In addition, a peel detection label according to another embodiment of the present invention may have a configuration in which an adhesive layer (W) formed from a composition that is a forming material different from that of the layer (Z) is laminated on the layer (Z). The adhesive layer (W) may be a single layer or a multilayer of two or more types.

FIG. 4 is a schematic cross-sectional view showing the state in which the peel detection label 102 shown in FIG. 2 is in the process of being peeled off from the adherend 40 after being affixed to the adherend 40, i.e., the state in which the peel detection label 102 is being peeled off.
A preferred embodiment of the peel detection label of the present invention is such that, when the peel detection label is peeled off, interfacial peeling occurs between the support and the pattern layer and/or between the pattern layer and the intermediate layer (C), making it possible to visually detect whether the peel detection label has been peeled off.
Here, the peel detection label of the present invention is preferably a label that, as shown in Figure 4, when the peel detection label 102 is peeled off from the adherend 40, interfacial peeling occurs between the support 1 and the pattern layer 2, resulting in a gap 50, thereby making the pattern apparent, and making it possible to visually detect whether the peel detection label 102 has been peeled off from the adherend 40.

That is, it is preferable that the peel detection label of one embodiment of the present invention satisfies the following requirement (1).
Requirement (1): After the adhesive layer (Z) of the peel detection label is affixed to an adherend, when it is peeled off from the adherend, interfacial peeling occurs between the support and the pattern layer, making it possible to visually detect whether or not the peel detection label has been peeled off from the adherend.

When the peel detection label of one embodiment of the present invention satisfies requirement (1), it is also preferable from the following viewpoint. For example, as described below with respect to the support, if the surface of the support facing the pattern layer is matte-finished, and interfacial peeling occurs between the support and the pattern layer, creating a gap in the peeled portion, light is diffusely reflected on the matte-finished surface exposed in the gap, and the peeled portion changes from transparent to translucent or opaque before and after peeling, forming a matte pattern. This further improves visibility when detecting peeling of the peel detection label.

The "adherend" described in the above requirement (1) refers to an adherend used when evaluating whether one characteristic of the peel detection label, i.e., whether the requirement (1) is satisfied, and is merely shown to explain the evaluation method. This can be said to be similar to, for example, an object to which an arbitrary label is attached, which is used for the purpose of measuring the adhesive strength when evaluating the "adhesive strength" of the arbitrary label, or a glass plate for preparing a preparation used when observing an arbitrary substance with a digital microscope. Therefore, the "adherend" described in requirement (1) is not a part (member) that constitutes the peel detection label of the present invention. In addition, it is not a provision for limiting the adherend to which the peel detection label of the present invention is affixed to a specific one.
In addition, in the present invention, "visually detectable" means that a change in the peel detection label before and after peeling can be visually confirmed by a human being.

Incidentally, in peel detection labels, plastic materials are necessary for making the labels into ones that allow changes resulting from interfacial peeling to be visually recognizable.
However, in recent years, there has been a demand to reduce the use of plastic materials in order to reduce the impact on the environment, and there is an increasing demand to not use plastic materials in peel detection labels as well.
In response to such demands, in one embodiment of the peel detection label of the present invention, a support having at least one paper base layer is used to reduce the impact on the environment, and the concealment rate of the peel detection label, measured in accordance with JIS K5600-4-1:1999, is adjusted to 75.0% or less in order to provide a peel detection label that makes it easy to visually check whether or not peeling has occurred.
In other words, since the peel detection label of one embodiment of the present invention has the concealment rate adjusted to 75.0% or less, when the label is peeled off after application and interfacial peeling occurs between the support and the pattern layer and/or between the pattern layer and layer (C), it becomes possible to visually detect whether or not peeling has occurred.

In addition, it is preferable that the peel detection label of one embodiment of the present invention is capable of visually recognizing at least the change caused by the interfacial peeling by visual observation from the support side when attached to an adherend. Such a peel detection label is excellent in terms of workability because the presence or absence of peeling can be confirmed only by visual observation from the support side without touching it.
In order to obtain a peel detection label having such characteristics, the lower the hiding rate, the more preferable.
From the above viewpoint, in the peel-off detection label of one embodiment of the present invention, the concealment rate is preferably 70.0% or less, more preferably 60.0% or less, more preferably 50.0% or less, even more preferably 45.0% or less, even more preferably 40.0% or less, still more preferably 35.0% or less, and particularly preferably 30.0% or less, and may also be 1.0% or more, 3.0% or more, 5.0% or more, 7.0% or more, or 10.0% or more.
In this specification, the concealment rate of the peel detection label refers to a value measured in accordance with JIS K5600-4-1: 1999. In addition, in cases where the peel detection label has a release material, the value is measured after removing the release material, and the specific measurement method is as described in the examples below.

The total light transmittance (Tt) of the peel detection label of one embodiment of the present invention is preferably 30% or more, more preferably 35% or more, from the viewpoint of making it easier to visually check the presence or absence of peeling and providing a peel detection label with excellent workability, and from the viewpoint of making the presence or absence of peeling easily checkable by visual observation from the support side, it is more preferably 40% or more, more preferably 50% or more, even more preferably 60% or more, even more preferably 70% or more, even more preferably 75% or more, particularly preferably 80% or more, and may also be less than 100%, 95% or less, 90% or less, 85% or less, or 83% or less.

The diffuse transmittance (Td) of the peel detection label of one embodiment of the present invention is preferably 30% or more, more preferably 35% or more, from the viewpoint of making it easier to visually check the presence or absence of peeling and providing a peel detection label with excellent workability, and from the viewpoint of making the presence or absence of peeling easily checkable by visual observation from the support side, it is more preferably 40% or more, more preferably 45% or more, even more preferably 50% or more, even more preferably 55% or more, particularly preferably 60% or more, and may also be 90% or less, 85% or less, 80% or less, 75% or less, or 70% or less.

The haze of the peel detection label of one embodiment of the present invention is preferably 40% or more, more preferably 50% or more, even more preferably 60% or more, even more preferably 65% or more, and particularly preferably 70% or more, from the viewpoint of making it easier to visually check the presence or absence of peeling and providing a peel detection label with excellent workability, and may also be less than 100%, 99% or less, or 98% or less.

The difference (|Tt - Td|) between the total light transmittance (Tt) and the diffuse transmittance (Td) of the peel detection label of one embodiment of the present invention is, from the viewpoint of making it easier to visually check the presence or absence of peeling and providing a peel detection label with excellent workability, preferably 0.10% or more, more preferably 0.15% or more, more preferably 0.30% or more, even more preferably 0.50% or more, even more preferably 1.00% or more, still more preferably 1.50% or more, particularly preferably 2.00% or more, and is also preferably 30.0% or less, more preferably 27.0% or less, even more preferably 25.0% or less, still more preferably 23.0% or less, particularly preferably 21.0% or less.

In this specification, the total light transmittance (Tt) and diffuse transmittance (Td) of the peel detection label are values measured in accordance with JIS K7361-1: 1997. The haze is a value calculated from the following formula using the total light transmittance (Tt) and diffuse transmittance (Td) values measured by the above method.
・Haze (%) = Diffuse transmittance (Td) / Total light transmittance (Tt) x 100
When the peel detection label has a release material, the release material is removed and the measurement is performed according to the above method. The specific measurement method is as described in the examples below.

The adhesive strength of the peel detection label of one embodiment of the present invention is preferably 0.3 N/25 mm or more, more preferably 0.5 N/25 mm or more, more preferably 1.0 N/25 mm or more, even more preferably 2.0 N/25 mm or more, still more preferably 3.0 N/25 mm or more, and particularly preferably 4.0 N/25 mm or more, and from the viewpoint of obtaining a peel detection label with good releasability when peeled, it is preferably 30 N/25 mm or less, more preferably 25 N/25 mm or less, even more preferably 22 N/25 mm or less, still more preferably 20 N/25 mm or less, and particularly preferably 16 N/25 mm or less.
The adhesive strength of the peel detection label can be measured by the method described in the Examples.

The thickness of the peel detection label of one embodiment of the present invention is preferably 5 to 400 μm, more preferably 10 to 250 μm, even more preferably 20 to 200 μm, still more preferably 30 to 150 μm, still more preferably 40 to 130 μm, and even more preferably 55 to 120 μm. Here, when the peel detection label is an embodiment in which a release material is further laminated as described above, the thickness of the peel detection label refers to the total thickness of the peel detection label excluding the release material.
The thickness of the peel detection label can be measured by the method described in the Examples.

Hereinafter, each configuration of the peel detection label according to one embodiment of the present invention will be described.
In addition, in the description of each layer below in this specification, matters related to each layer (type and content of components contained in each layer, physical properties or properties of each layer, layer structure of each layer, function of each layer, etc.) can be incorporated not only by referring to the matters described below but also by referring to the matters described in WO 2020/203344.

<Support>
The support of the peel detection label of one embodiment of the present invention has at least one paper base layer.
The peel-off detection label of one embodiment of the present invention uses a support having at least one paper base layer, and therefore can be a peel-off detection label with reduced impact on the environment.
There are no particular limitations on the paper material constituting the paper base layer, so long as the hiding rate of the peel detection label is adjusted to fall within the above-mentioned range.

The support used in one embodiment of the present invention may be composed of one paper base layer, or may be composed of two or more paper base layers.
In addition, the support used in one embodiment of the present invention may be a laminated paper having a resin layer containing a thermoplastic resin such as polyethylene on one or both sides of a paper base layer. From the viewpoint of reducing the impact on the environment, however, it is preferable that the resin layer is as thin as possible, and it is more preferable that no resin layer is present.
When the support used in one embodiment of the present invention has one or more paper base layers and a resin layer, the ratio of the thickness of the resin layer to the total thickness of the paper base layers [resin layer/paper base layer] is preferably 0 to 0.20, more preferably 0 to 0.10, more preferably 0 to 0.05, even more preferably 0 to 0.01, still more preferably 0 to 0.001, and particularly preferably 0 to 0.0001.

The support used in one embodiment of the present invention is preferably composed only of one or more layers of paper substrate. A peel detection label having such a support has the advantage that after being affixed to an adherend and before being peeled off, the pattern is difficult to confirm even when observed from any direction, making it difficult to notice that it is a peel detection label.

From the viewpoint of reducing the impact on the environment and from the viewpoint of producing a peel detection label in which the pattern is difficult to confirm even when observed from any direction after being affixed to an adherend and before being peeled off, it is preferable that the support used in one embodiment of the present invention does not have a resin film having a tensile modulus at 23°C of 50 MPa or more and 1000 MPa or less.

The breaking strength at 23°C of the support used in one embodiment of the present invention is preferably 30 MPa or more, more preferably 50 MPa or more, more preferably 60 MPa or more, even more preferably 70 MPa or more, even more preferably 75 MPa or more, even more preferably 85 MPa or more, even more preferably 100 MPa or more, and particularly preferably 120 MPa or more, from the viewpoint of suppressing breakage during use and providing a peel detection label with good workability, and is preferably 500 MPa or less, more preferably 400 MPa or less, more preferably 300 MPa or less, even more preferably 250 MPa or less, even more preferably 200 MPa or less, and particularly preferably 150 MPa or less, from the viewpoint of providing a peel detection label that is easy to process, such as by cutting.

The tensile modulus at 23°C of the support used in one embodiment of the present invention is preferably more than 1000 MPa, more preferably 2000 MPa or more, more preferably 2700 MPa or more, more preferably 3700 MPa or more, even more preferably 4200 MPa or more, even more preferably 4400 MPa or more, still more preferably 4700 MPa or more, still more preferably 5200 MPa or more, still more preferably 5700 MPa or more, particularly preferably 6000 MPa or more, and may also be 20000 MPa or less, 17000 MPa or less, 15000 MPa or less, 12000 MPa or less, or 10000 MPa or less.
The tensile modulus at 23° C. of the support used in another embodiment of the present invention may be less than 50 MPa, 40 MPa or less, or 30 MPa or less, or may be 1 MPa or more, 5 MPa or more, or 10 MPa or more.

In this specification, the breaking strength and tensile modulus of the support at 23°C refer to values measured based on the method described in the Examples below.

The thickness of the support used in one embodiment of the present invention is preferably 10 μm or more, more preferably 15 μm or more, even more preferably 20 μm or more, even more preferably 25 μm or more, and particularly preferably 27 μm or more, from the viewpoint of obtaining a peel detection label that is easy to maintain its shape and has good workability when affixed to an adherend and when peeled off from the adherend, and is preferably 150 μm or less, more preferably 130 μm or less, even more preferably 110 μm or less, even more preferably 100 μm or less, and particularly preferably 90 μm or less, from the viewpoint of obtaining a peel detection label that suppresses the adverse effect of peeling over time when affixed to an adherend.

The degree of beating of the support used in one embodiment of the present invention, as measured in accordance with JIS P8121-1:2012, is, from the viewpoint of obtaining a peel detection label with good pattern expression after peeling, preferably 20 mL or more, more preferably 30 mL or more, even more preferably 50 mL or more, still more preferably 60 mL or more, and particularly preferably 70 mL or more, and there is no particular upper limit, but it is, for example, 110 mL or less.
In this specification, the degree of beating means a value measured in accordance with the Shopper-Riegler method of JIS P8121-1:2012.

The basis weight of the support used in one embodiment of the present invention is, from the viewpoint of adjusting the hiding rate of the peel detection label within the above-mentioned range, imparting appropriate elasticity to the support, and providing a peel detection label with good pattern expression upon peeling, preferably 20 g/m2 or ^more , more preferably 25 g/ ^m2 or more, even more preferably 30 g/m2 or ^more , still more preferably 32 g/m2 or ^more , and particularly preferably 35 g/m2 or ^more , and is preferably 120 g/m2 or ^less , more preferably 110 g/m2 ^{or less} , even more preferably 100 g/m2 or ^less , still more preferably 90 g/m2 or ^less , and particularly preferably 80 g/m2 or ^less .
In this specification, the basis weight refers to a value measured in accordance with JIS P8124:2011.

The hiding rate of the support used in one embodiment of the present invention is preferably 75.0% or less, more preferably 70.0% or less, more preferably 60.0% or less, more preferably 50.0% or less, even more preferably 45.0% or less, even more preferably 40.0% or less, even more preferably 35.0% or less, and particularly preferably 30.0% or less, and may also be 1.0% or more, 3.0% or more, 5.0% or more, 7.0% or more, or 10.0% or more.

<Pattern Layer>
The pattern layer of the peel detection label of the present invention is a layer necessary for making it possible to visually detect the peeling of the peel detection label when the peel detection label is peeled off.
The pattern layer is preferably a layer formed from a material that satisfies the above-mentioned requirement (1) in the peel detection label.
Moreover, since it is preferable that the pattern layer is latent before the peeling detection label is peeled off, it is preferable that the pattern layer is a transparent layer. By using a transparent pattern layer, the change before and after peeling of the peeling detection label becomes clearer, and when the peeling detection label is attached to the adherend, it is possible to confirm information such as characters and patterns on the adherend surface through the peeling detection label, or the peeling detection label itself becomes transparent and the label can be made inconspicuous.

The pattern layer is preferably a layer formed from a pattern layer forming composition containing a pattern layer forming resin.
The resin for forming the pattern layer is not particularly limited as long as the effects of the present invention are exhibited, but examples thereof include cellulose-based resins such as methyl cellulose, carboxymethyl cellulose, and hydroxyethyl cellulose; acrylic resins such as poly(meth)acrylate and polymethyl (meth)acrylate; urethane-based resins; acrylic urethane-based resins; polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polyarylate; epoxy-based resins; and the like.
These resins for forming the pattern layer may be used alone or in combination of two or more kinds.
The resin for forming the pattern layer used in one embodiment of the present invention preferably contains one or more selected from an acrylic resin, a urethane resin, an acryl urethane resin, and a polyester resin, more preferably contains one or more selected from an acrylic resin and an acryl urethane resin, and even more preferably contains an acrylic resin.

In addition, when layer (C) is an adhesive layer that is used to form a peel detection label that is likely to satisfy requirement (1), the pattern layer preferably contains a resin that has a lower adhesive strength than layer (C). Therefore, the resin for forming the pattern layer preferably contains a non-adhesive resin. The adhesive strength of layer (C) refers to the adhesive strength of layer (X1) that is located closest to the pattern layer.

In addition, from the viewpoint that interfacial peeling between the support and the pattern layer occurs more easily when the peel detection label is peeled off and requirement (1) is easily satisfied, it is preferable that the adhesive strength between the pattern layer and the support is lower than the adhesive strength between layer (C) (for example, when layer (C) is a layer including layers (X) and (Y), it refers to layer (X), and when layer (X) is formed from a plurality of layers, it refers to layer (X1) in contact with the pattern layer) and the support, and it is more preferable that the adhesive strength between the pattern layer and the support is lower than the adhesive strength between layer (C) and the support and lower than the adhesive strength between the pattern layer and layer (C). In such an embodiment, peeling at an interface other than the interface between the support and the pattern layer is more effectively prevented, which is preferable for satisfying requirement (1).

The content of the resin for forming the pattern layer is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to the total mass of the pattern layer (100% by mass) or the total amount of the composition for forming the pattern layer (100% by mass), and is preferably 100% by mass or less.

In addition, the pattern layer is formed on a part of the surface of the support. If the pattern layer is formed on the entire surface of the support, peeling occurs at the entire interface between the support and the pattern layer, resulting in adhesive residue on the adherend.
Here, the term "formed on a part of the surface of the support" means that, in the size of the peel detection label when it is actually affixed, or in the peel detection label after it has been cut into a predetermined size for use, the area on the surface of the support on which the pattern layer is formed is usually less than 100%, preferably 1 to 99%, more preferably 2 to 95%, more preferably 3 to 90%, even more preferably 5 to 80%, even more preferably 8 to 70%, still more preferably 10 to 60%, and particularly preferably 12 to 45%.

The method for forming the pattern layer is not particularly limited as long as it is a method capable of forming a pattern layer on the support. For example, the pattern layer can be formed by a general printing method such as gravure printing, screen printing, offset printing, flexographic printing, etc., using an ink containing the resin and a solvent.
Furthermore, the shape of the pattern to be formed is not particularly limited as long as it is possible to detect whether or not the peel detection label has been peeled off, and it may be a geometric pattern or design, or a character pattern.
The pattern is not necessarily limited to one "arranged" based on a certain regularity, but also includes irregular (random) shapes. For example, when the printing method is not limited to printing a specific regular shape, but is simply sprayed onto a support to form an irregular (random) shape, even if the color tone or light transmittance of the label randomly changes in some places and can be visually recognized, the places formed from the pattern layer material formed on the support are included in the pattern layer.
However, from the standpoint of more reliably and clearly detecting whether or not the peel detection label has been peeled off, and from the standpoint of production and product quality standpoints such as being able to form a pattern layer suitable for any label size regardless of the size of the label processed, it is preferable that an interface between the support and the pattern layer exists over a certain area or more, and therefore it is preferable to form a predetermined regular pattern.

As mentioned above, since the pattern layer itself can form a predetermined pattern, if the pattern layer is a transparent layer, the pattern can be formed as a hidden pattern such as hidden characters. Here, "hidden pattern" refers to a pattern in which, before the peel detection label is peeled off, the formed pattern is transparent and therefore latent and cannot be visually detected, but becomes apparent after the peel detection label is peeled off, making it possible to visually detect the pattern.

In addition, when the above-mentioned requirement (1) is satisfied, the pattern layer used in the present invention has the advantage that the pattern layer itself is peeled off at the interface from the support, and therefore it is not necessary to provide layers with separate functions, such as a peeling layer and a printing layer, as the pattern layer.
By configuring the peel detection label as described above, it is possible to cause interfacial peeling between the support and the pattern layer, while effectively suppressing interfacial peeling at other locations. Therefore, even if a relatively intricate pattern such as letters is formed in the pattern layer itself, it is possible to display the pattern to a degree that can be visually detected when the peel detection label is peeled off, so it is preferable to configure the peel detection label to satisfy the requirement (1).

The thickness of the pattern layer may be less than the thickness of the adhesive laminate described below, and is preferably less than the thickness of layer (C). The specific thickness of the pattern layer is preferably 0.05 to 16 μm, more preferably 0.1 to 12 μm, and even more preferably 0.5 to 8 μm.

It is preferable that the surface of the support on the side where the pattern layer is formed and the surface of the pattern layer on the side where the intermediate layer (C) is formed are surfaces that have been subjected to a surface modification treatment using an oxidation method. In this embodiment, the interfacial adhesion between the support and the layer (C) and the interfacial adhesion between the pattern layer and the layer (C) are improved, and interfacial peeling at these interfaces can be more effectively prevented. This is preferable because interfacial peeling is more likely to occur at the interface between the support and the pattern layer, not at the interface between the pattern layer and the layer (C). In other words, it is preferable because it is easier to satisfy the requirement (1).
Examples of the oxidation method include a corona discharge treatment method, a plasma treatment method, a chromic acid oxidation method (wet type), a hot air treatment method, an ultraviolet treatment method, an ozone treatment method, and an ultraviolet-ozone treatment method.

<Adhesive laminate>
The adhesive laminate of the peel detection label of the present invention has at least an intermediate layer (C) and an adhesive layer (Z), and preferably has at least layer (C) and layer (Z) in this order from the pattern layer side, and more preferably is a laminate in which at least layer (C) and layer (Z) are directly laminated in this order from the pattern layer side.

<<Intermediate layer (C)>>
The intermediate layer (C) may be a single layer or a multilayer consisting of two or more layers.
In the peel detection label of one embodiment of the present invention, the intermediate layer (C) includes at least a coating layer (X) and a substrate layer (Y), and the surface of the substrate layer (Y) that contacts the pressure-sensitive adhesive layer (Z) It is preferable that the laminate has the following structure.

[Coating layer (X)]
The coating layer (X) has a surface in contact with the support and the pattern layer and a surface in contact with the base layer (Y). The layer (X) may be a single layer or a laminate consisting of two or more layers.
For example, when the coating layer (X) is a laminate (L2) having a first coating layer (X1) and a second coating layer (X2), it is preferable that the first coating layer (X1) is a layer in contact with the surface of the support and the pattern layer, and the second coating layer (X2) is a layer in contact with the base layer (Y).
Each of the layers constituting the layer (X) is preferably a resin layer formed from a resin composition containing a resin, that is, the layer (X) is preferably a layer composed of a resin layer.

At least one of the surfaces of the layer (X) in contact with the support and the pattern layer or the surface in contact with the layer (Y) preferably has adhesiveness. Therefore, the layer (X) preferably has at least an adhesive layer (XA) (hereinafter, also referred to as "layer (XA)").
The layer (XA) is preferably a layer formed from a composition (x) containing an adhesive resin, and more preferably a layer formed by drying a coating film (x') made of the composition (x) containing an adhesive resin.
In this specification, the term "coating film" refers to a film formed from a composition, which is a forming material, by a known coating method, in which the residual rate of volatile components such as solvents contained in the film is 10 to 100 mass % relative to the total amount of volatile components contained in the composition before coating (100 mass %).
In other words, in this specification, the coating film contains a certain amount of volatile components such as solvents.

In addition, it is preferable that the layer in contact with layer (Y) of layer (X) is layer (XA). This embodiment improves the interfacial adhesion between layer (X) and layer (Y), and makes the interface between layer (X) and layer (Y) in the adhesive laminate less susceptible to peeling due to the tensile stress generated during the deformation of the peel detection label when the peel detection label is peeled off, which is thought to contribute to improving the effect of suppressing the occurrence of adhesive residue.

In addition, when the layer (X1), which is the first layer from the support side, is layer (XA), it is preferable that the pattern layer and layer (XA) each contain the same type of resin. For example, when the pattern layer is a layer formed from an acrylic resin, it is preferable that the adhesive layer (XA) is also an acrylic resin.

The composition (x) which is a material for forming the pressure-sensitive adhesive layer (XA) is a composition containing a pressure-sensitive adhesive resin.
In one embodiment of the present invention, the components other than the adhesive resin contained in the composition (x) can be appropriately adjusted depending on the intended use of the peel detection label of the present invention.
For example, in one embodiment of the present invention, from the viewpoint of adjusting the adhesive strength to a desired range, the composition (x) containing an adhesive resin may further contain, in addition to the adhesive resin, one or more selected from the group consisting of a tackifier and a crosslinking agent, and may also contain, in addition to these, one or more selected from the group consisting of a dilution solvent and an adhesive additive used in general adhesives.

The mass average molecular weight (Mw) of the adhesive resin is preferably from 10,000 to 2,000,000, more preferably from 20,000 to 1,500,000, and even more preferably from 30,000 to 1,200,000.
Examples of the adhesive resin contained in the composition (x) include acrylic resins, urethane resins, polyisobutylene resins, olefin resins, acrylic urethane resins, polyester resins, etc., which satisfy the adhesive strength of the layer (XA) described below. Among these, preferably one or more resins selected from the group consisting of acrylic resins, urethane resins, acrylic urethane resins, and polyester resins, more preferably acrylic resins.
These adhesive resins may be used alone or in combination of two or more kinds.
Furthermore, when these adhesive resins are copolymers having two or more types of constituent units, the form of the copolymer is not particularly limited and may be any of a block copolymer, a random copolymer, and a graft copolymer.
Furthermore, when the layer in contact with the layer (Y) is the layer (XA), from the viewpoint of further improving the interfacial adhesion between the layer (XA) and the layer (Y), it is preferable that these adhesive resins are non-ultraviolet-curable adhesive resins having no polymerizable functional group.

The content of the adhesive resin in the composition (x) forming the layer (XA) is preferably 30 to 99.99% by mass, more preferably 40 to 99.95% by mass, even more preferably 50 to 99.90% by mass, still more preferably 55 to 99.80% by mass, and even more preferably 60 to 99.50% by mass, based on the total amount (100% by mass) of the active ingredients in the composition (x).

[Base layer (Y)]
From the viewpoint of achieving both prevention of adhesive residue on the adherend and better pattern expression in a peel detection label, it is preferable that the base material layer (Y) is a layer having a tensile storage modulus E' (hereinafter also referred to as "elastic modulus E'") at 23°C of 10 MPa or more and 800 MPa or less.
Furthermore, from the viewpoint of achieving both prevention of adhesive transfer onto the adherend and better pattern expression, the elastic modulus E' of layer (Y) is more preferably 15 MPa or more, even more preferably 18 MPa or more, even more preferably 50 MPa or more, even more preferably 100 MPa or more, even more preferably 200 MPa or more, and more preferably 700 MPa or less, even more preferably 600 MPa or less, even more preferably 500 MPa or less, even more preferably 400 MPa or less, and even more preferably 300 MPa or less.
From the viewpoint of obtaining better pattern development, the layer (Y) is preferably a layer having a higher elastic modulus E' than the elastic modulus E' of the support.
When the value of the elastic modulus E' of the layer (Y) exceeds 100 MPa, it means the value of the tensile storage modulus E' at 23°C measured by a tensile method. When the value measured by the tensile method is 100 MPa or less, it means the value of the tensile storage modulus E' at 23°C converted from the shear storage modulus G' at 23°C measured by a torsional shear method. Specifically, it can be measured by the method described in the Examples.
The elastic modulus E' of the layer (Y) can also be adjusted by, for example, selecting the types of each component forming the layer (Y), such as a resin, a crosslinking agent, a catalyst, and an additive, and adjusting the contents thereof, as described below.

The layer (Y) is preferably a layer formed from a composition (y) containing one or more non-sticky resins (y1) selected from the group consisting of acrylic urethane resins and olefin resins, and more preferably a layer formed by drying a coating film (y') made of a composition (y) containing one or more non-sticky resins (y1) selected from the group consisting of acrylic urethane resins and olefin resins.
When layer (Y) is a layer formed by drying coating film (y') made of composition (y), it becomes an unstretched film-like or sheet-like product, and therefore has significantly superior flexibility compared to layer (Y) composed of a plastic film or sheet obtained by a method such as melt extrusion molding.
Therefore, when layer (Y) is a layer formed by drying coating film (y') made of composition (y), when the peel detection label is peeled off, layer (Y) is more likely to undergo the deformation necessary for pattern development, and the adhesive laminate is less likely to break even when the tensile stress generated in the peel detection label is greater, so it is thought that it becomes easier to achieve both excellent pattern development and prevention of adhesive residue.
Here, "unstretched film-like or sheet-like material" has the same meaning as in the explanation of "unstretched film" in the present specification above, except that "film" is changed to "film-like material or sheet-like material."

For details of one or more non-adhesive resins (y1) selected from the group consisting of acrylic urethane resins and olefin resins, and various additives contained in composition (y), which is the material for forming layer (Y), refer to the descriptions in WO 2020/203344.

<<Pressure-sensitive adhesive layer (Z)>>
The pressure-sensitive adhesive layer (Z) is preferably a layer formed from a composition (z) containing a pressure-sensitive adhesive resin, and more preferably a layer formed by drying a coating film (z') made of a composition (z) containing a pressure-sensitive adhesive resin.
The composition (z), which is a material for forming the adhesive layer (Z), contains an adhesive resin, and as the adhesive resin, the same adhesive resin as that described above as the adhesive resin related to the composition (x) can be used, and the preferred aspects and composition (content) thereof are also the same.
However, as the monomer (a1') of the acrylic resin, which is a suitable example of the adhesive resin forming the layer (Z), one or more selected from the group consisting of 2-ethylhexyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate are more preferable, and one or more selected from the group consisting of 2-ethylhexyl (meth)acrylate and butyl (meth)acrylate are even more preferable. Similarly, as the monomer (a2') of the acrylic resin, which is a suitable example of the adhesive resin forming the adhesive layer (Z), it is more preferable to contain both 2-hydroxyethyl (meth)acrylate and (meth)acrylic acid. Similarly, as the monomer (a3') of the acrylic resin, which is a suitable example of the adhesive resin forming the adhesive layer (Z), vinyl acetate is preferable. Note that the acrylic resin, which is a suitable example of the adhesive resin forming the adhesive layer (Z), may or may not have a structural unit (a3) derived from the monomer (a3').

In one embodiment of the present invention, the components other than the adhesive resin contained in the composition (z) can be appropriately adjusted depending on the intended use of the peel detection label of the present invention.
For example, in one embodiment of the present invention, from the viewpoint of adjusting the adhesive strength to a desired range, composition (z) may further contain one or more selected from the group consisting of a tackifier and a crosslinking agent, and may also contain, in addition to these, one or more selected from the group consisting of a dilution solvent and an adhesive additive used in a general adhesive.
The tackifier, crosslinking agent, diluting solvent, and pressure-sensitive adhesive additives used in general pressure-sensitive adhesives may be the same as those described in the description of the composition (x) above, and the preferred embodiments and contents thereof are also the same.
However, in a preferred embodiment of the present invention, as described below, the adhesive strength of the layer (XA) is preferably equal to or greater than the adhesive strength of the layer (Z), and it is more preferable that the adhesive strength of the layer (XA) is greater than the adhesive strength of the layer (Z).

The peel detection label may further include a colorant in the support and/or at least one layer selected from the layers described above. The phrase "at least one layer selected from the layers described above contains a colorant" refers to, for example, when layer (C) is a laminate, at least one layer selected from the layers constituting layer (C) contains a colorant, and the same applies to layers (X), (Y), and (Z).
When the support and/or at least one layer selected from the above-mentioned layers contains an appropriate colorant in consideration of visibility and concealment, the visibility of the peel detection pattern is further improved, and it becomes easier to detect whether the peel detection label has been peeled or not. From the same viewpoint, when the support and/or at least one layer selected from the above-mentioned layers contains a colorant, it is more preferable that at least one layer selected from the above-mentioned layers contains a colorant.

The thickness of the adhesive laminate (total thickness of the adhesive laminate) is preferably 2 to 100 μm, more preferably 4 to 80 μm, even more preferably 5 to 50 μm, even more preferably 10 to 40 μm, and even more preferably 15 to 35 μm.

The thickness (Xt) of the layer (X) is preferably 0.5 to 50.0 μm, more preferably 1.0 to 30.0 μm, even more preferably 2.0 to 20.0 μm, even more preferably 3.0 to 15.0 μm, and even more preferably 4.0 to 12.0 μm.

When the layer (X) is a laminate (Lm), the ratio of the thickness (Xmt) of the layer (Xm) to the thickness (X1t) of the layer (X1) [(X1t)/(Xmt)] is preferably 1/100 to 200/100, more preferably 2/100 to 150/100, even more preferably 3/100 to 100/100, still more preferably 5/100 to 50/100, and even more preferably 8/100 to 20/100.
For example, when the laminate (Ln) is a laminate (L2) consisting of two layers, the ratio of the thickness (X2t) of the layer (X2) to the thickness (X1t) of the layer (X1) [(X1t)/(X2t)] is preferably 1/100 to 200/100, more preferably 2/100 to 150/100, even more preferably 3/100 to 100/100, still more preferably 5/100 to 50/100, and even more preferably 8/100 to 20/100.

The thickness (Yt) of the layer (Y) is preferably 0.5 to 50.0 μm. By making the thickness (Yt) of the layer (Y) 0.5 μm or more, the layer (Y) is less likely to break when the peel detection label is peeled off, which is thought to make it easier to achieve both better pattern expression and prevention of adhesive residue. In addition, by making the thickness (Yt) of the layer (Y) 50.0 μm or less, the peel angle when peeling off the peel detection label is smaller, and the stress trying to peel between the support and the pattern layer is easily transmitted to the pattern layer side, resulting in better pattern expression. From this perspective, the thickness (Yt) of the layer (Y) is more preferably 1.0 to 30.0 μm, even more preferably 2.0 to 20.0 μm, even more preferably 2.5 to 15.0 μm, even more preferably 3.0 to 12.0 μm, and even more preferably 3.0 to 9.0 μm.

In the peel detection label, the ratio of the thickness (Xt) of the layer (X) to the thickness (Yt) of the layer (Y) [(Xt)/(Yt)] is preferably 20/100 to 500/100, more preferably 80/100 to 400/100, and even more preferably 180/100 to 300/100.
In the peel detection label, the ratio of the thickness (Zt) of the layer (Z) to the thickness (Yt) of the layer (Y) [(Zt)/(Yt)] is preferably 10/100 to 500/100, more preferably 100/100 to 400/100, and even more preferably 200/100 to 300/100.
Furthermore, when the peel detection label has the other adhesive layer (Wr) (r is an integer of 1 or more) described above, the thickness of these layers is not particularly limited as long as the effects of the present invention are exhibited independently.

<Release material>
As described above, from the viewpoint of handleability, the peel detection label of one embodiment of the present invention may further have a release material on the application surface 10a, 11a, 12a of the adhesive laminate, for example, in the embodiment shown in Figures 1 to 3. Moreover, in any of the embodiments shown in Figures 1 to 3, a release material may be further provided on the surface of the support 1 opposite the adhesive laminate, so that the label is sandwiched between two release materials. When two release materials are used, the respective release materials may be the same or different from each other.
As the release material, a release sheet with double-sided release treatment or a release sheet with one-sided release treatment is used, and examples thereof include a release material substrate having a release agent applied thereon.

[Method of manufacturing peel detection label]
The method for producing the peel detection label of one embodiment of the present invention is not particularly limited, and examples thereof include the method described in WO 2020/203344.
However, when the process of forming each layer of the peel detection label includes a step of curing the layer by irradiating it with ultraviolet light, it is preferable to carry out a step of forming an ultraviolet absorbing layer after that step.

[Use of peel detection labels]
A peeling detection label according to one embodiment of the present invention can be a peeling detection label that allows easy visual confirmation of whether or not peeling has occurred while reducing the impact on the environment, and can be suitably used in a variety of applications where security is required.
Furthermore, since the peel detection label of one embodiment of the present invention does not leave any adhesive residue on the substrate, it can be suitably used in applications where it is undesirable for adhesive residue to be left on the substrate when the peel detection label is peeled off when peeling is required, and where peel detection is required.

Specific uses of the peel detection label of one embodiment of the present invention are expected to include, for example, preventing tampering with the display content of automobile parts, electrical/electronic parts, precision machinery parts, etc.; preventing improper packaging or opening of goods when consigning or packaging them; sealing labels to guarantee the virginity of the contents of medicines, cosmetics, food, etc.; preventing improper opening and closing of various openings on vehicles such as various passenger cars, airplanes, trains, ships, etc. (for example, to prevent improper mixing of foreign objects into transport entrances or fuel tanks, etc.); preventing peeling or tampering with identification or certification labels such as various certificates such as passports and product certifications; and security measures such as preventing improper intrusion into vehicles such as various passenger cars, airplanes, trains, ships, etc. and preventing improper intrusion into various buildings.
Furthermore, since the peel-off detection label of one embodiment of the present invention has an appearance similar to that of a normal label, and no pattern can be confirmed when observed from any direction before peeling, it can also be suitably used in applications where it is desired that the peel-off detection label not be recognized.

The peel detection label can be attached to the object (adherend) in these applications, and when peeled from the adherend, interfacial peeling occurs between the support and the pattern layer as described above, making it possible to visually detect whether the peel detection label has peeled off from the adherend.

The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples. Parts and percentages in each example are by weight unless otherwise specified.
The physical properties were measured by the methods described below.

(1) Mass average molecular weight (Mw), number average molecular weight (Mn)
Measurements were carried out using a gel permeation chromatograph (manufactured by Tosoh Corporation, product name "HLC-8020") under the conditions below, and the values measured were converted into standard polystyrene equivalent values.
(Measurement conditions)
Column: "TSK guard column HXL-L", "TSK gel G2500HXL", "TSK gel G2000HXL" and "TSK gel G1000HXL" (all manufactured by Tosoh Corporation) connected in sequence Column temperature: 40°C
Developing solvent: tetrahydrofuran Flow rate: 1.0 mL/min (2) Thickness of each layer A constant pressure thickness measuring instrument manufactured by Teclock Corporation (model number: "PG-02J", standard specifications: JIS K6783:1994, JIS Z1702: 1994, JIS Z1709:1995).

(3) Breaking strength and tensile modulus of support The support to be measured was cut into a strip shape of 10 mm wide × 80 mm long to prepare a test piece. A tensile test was carried out using a universal tensile tester (manufactured by Shimadzu Corporation, product name "Autograph") under conditions of 23°C and a relative humidity of 50%, with a chuck distance of 50 mm and a tensile speed of 200 mm/min, to measure the breaking strength and tensile modulus at 23°C (both in units of MPa).
(4) Beating Degree of Support The beaten degree of the support was measured in accordance with the Schopper-Riegler method of JIS P8121-1:2012.
(5) Basis Weight of Support Measured in accordance with JIS P8124:2011.

Production Example 1
(Preparation of composition (xa))
100 parts by mass (solid content ratio) of an adhesive resin, an acrylic copolymer (1) (an acrylic copolymer having structural units derived from raw material monomers consisting of n-butyl acrylate (BA) / methyl methacrylate (MMA) / vinyl acetate (VAc) / 2-hydroxyethyl acrylate (2HEA) = 80.0 / 10.0 / 9.0 / 1.0 (mass ratio), Mw: 1 million, dilution solvent: ethyl acetate, solid content concentration: 45 mass%), As a crosslinking agent, 25 parts by mass (solid content ratio) of a hydrogenated rosin-based resin (manufactured by Arakawa Chemical Industries, Ltd., product name "KE-359", softening point: 94 to 104°C) and 1.62 parts by mass (solid content ratio) of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "Takenate (registered trademark) D-110N") were blended and mixed, and further diluted with toluene and stirred uniformly to prepare a composition (x-a) having a solid content concentration (active ingredient concentration) of 40 mass%.

Production Example 2
(Preparation of composition (y))
(1) Synthesis of Linear Urethane Prepolymer (UY) In a reaction vessel under a nitrogen atmosphere, 100 parts by mass (solid content ratio) of polycarbonate diol having Mw=1,000 was mixed with isophorone diisocyanate such that the equivalent ratio of the hydroxyl groups of the polycarbonate diol to the isocyanate groups of isophorone diisocyanate was 1/1, and 160 parts by mass of toluene was further added. The mixture was stirred under a nitrogen atmosphere and reacted at 80° C. for 6 hours or more until the isocyanate group concentration reached the theoretical amount.
Next, a solution prepared by diluting 1.44 parts by mass (solid content ratio) of 2-hydroxyethyl methacrylate (2-HEMA) with 30 parts by mass of toluene was added, and the mixture was further reacted at 80° C. for 6 hours until the isocyanate groups at both ends disappeared, thereby obtaining a linear urethane prepolymer (UY) having a mass average molecular weight (Mw) of 29,000.
(2) Synthesis of acrylic urethane resin (II) Into a reaction vessel under a nitrogen atmosphere were added 100 parts by mass (solid content ratio) of the linear urethane prepolymer (UY) obtained in (1) above, 117 parts by mass (solid content ratio) of methyl methacrylate (MMA), 5.1 parts by mass (solid content ratio) of 2-hydroxyethyl methacrylate (2-HEMA), 1.1 parts by mass (solid content ratio) of 1-thioglycerol, and 50 parts by mass of toluene, and the mixture was heated to 105° C. with stirring.
Then, a solution prepared by diluting 2.2 parts by mass (solid content ratio) of a radical initiator (manufactured by Japan Finechem Co., Ltd., product name "ABN-E") with 210 parts by mass of toluene was added dropwise into the reaction vessel over a period of 4 hours while maintaining the temperature at 105°C.
After the dropwise addition of the solution was completed, the mixture was reacted at 105° C. for 6 hours to obtain a solution of an acrylic urethane resin (II) having a Mw of 105,000.
(3) Preparation of composition (y) 100 parts by mass (solid content ratio) of the solution of the acrylic urethane resin (II) obtained in (2) above, which is the non-tacky resin (y1), was mixed with 6.3 parts by mass (solid content ratio) of a hexamethylene diisocyanate crosslinking agent (manufactured by Tosoh Corporation, product name "Coronate (registered trademark) HL") as a crosslinking agent, and 1.4 parts by mass (solid content ratio) of dioctyltin bis(2-ethylhexanoate) as a catalyst. Further, the mixture was diluted with toluene and stirred uniformly to prepare a composition (y) with a solid content concentration (active ingredient concentration) of 30% by mass.

Production Example 3
(Preparation of composition (z))
An adhesive resin, acrylic copolymer (2) (n-butyl acrylate (BA) / 2-ethylhexyl acrylate (2EHA) / acrylic acid (AAc) / 2-hydroxyethyl acrylate (2HEA) = 47.0 / 47.0 / 5.5 / 0.5 (mass ratio) acrylic copolymer having a structural unit derived from raw material monomers, Mw: 550,000, dilution solvent: ethyl acetate, solid content concentration: 40 mass%) 100 parts by mass (solid content ratio) was mixed with an isocyanate-based crosslinking agent (manufactured by Tosoh Corporation, product name "Coronate (registered trademark) L") as a crosslinking agent (solid content ratio), and these were mixed, further diluted with toluene and stirred uniformly to prepare a composition (z) with a solid content concentration (active ingredient concentration) of 30 mass%.

Production Example 4
(Preparation of Laminate (M2))
On the surface of a release agent layer of a release sheet (manufactured by Lintec Corporation, product name "SP-8LK Blue", thickness: 88 μm, glassine paper coated with polyolefin and subjected to a silicone release treatment), a coating film (z') made of composition (z) prepared in Production Example 3, a coating film (y') made of composition (y) prepared in Production Example 2 on the coating film (z'), and a coating film (x-a') made of composition (x-a) prepared in Production Example 1 on the coating film (y') were simultaneously applied in this order from the release sheet side using a multi-layer die coater (width: 250 mm).
The three coating layers thus formed were then simultaneously dried at a drying temperature of 125°C for 60 seconds to produce a laminate (M2) in which the adhesive layer (Z), the base layer (Y), and the second coating layer (X2) were directly laminated in this order from the release sheet side.
The pressure-sensitive adhesive layer (Z) had a thickness of 13 μm, the base layer (Y) had a thickness of 5 μm, and the second coating layer (X2) had a thickness of 10 μm.

Examples 1 to 3, Comparative Example 1, Reference Examples 1 to 2
(1) Regarding the Support Used Details of the support used are as follows.
Paper base material (1): Special function paper (product name "SUKEKAKE", manufactured by Lintec Corporation), basis weight = 77 g/m ² , hiding power = 71.8%, breaking strength (23°C) = 77.66 MPa, tensile modulus (23°C) = 4422.1 MPa, beating degree = 30 mL, thickness = 90 µm.
Paper base material (2): envelope paper (product name "Clear Window CoC", manufactured by Lintec Corporation), basis weight = 35 g/m ² , hiding power = 17.3%, breaking strength (23°C) = 132.94 MPa, tensile modulus (23°C) = 9960.2 MPa, beating degree = 90 mL or more, thickness = 28 μm.
Paper base material (3): tracing paper, basis weight = 40 g/m ² , hiding power = 28.6%, breaking strength (23°C) = 122.84 MPa, tensile modulus (23°C) = 6654.77 MPa, beating degree = 90 mL or more, thickness = 47 µm.
Paper base material (4): fine paper, basis weight = 55 g/m ² , hiding power = 83.4%, breaking strength (23°C) = 99.65 MPa, tensile modulus (23°C) = 4167.9 MPa, beating degree = 30 mL, thickness = 70 µm.
Resin film (1): A resin film having a matte surface obtained by embossing one surface of a polyethylene terephthalate film (manufactured by Toray Industries, Inc.), hiding ratio = 13.8%, breaking strength (23 ° C) = 162.35 MPa, tensile modulus (23 ° C) = 3637.1 MPa, thickness = 38 μm.
Resin film (2): An ethylene-methacrylic acid copolymer film (manufactured by RIKEN TECHNOS CORPORATION, methacrylic acid content: 9% by mass) having one surface embossed to give a matte surface. Concealment ratio = 4.2%, breaking strength (23 ° C) = 25.4 MPa, tensile modulus (23 ° C) = 164.1 MPa, thickness = 80 μm.

(2) Formation of Pattern Layer On one surface of the support of the type shown in Table 1 (on the matte surface in Reference Examples 1 and 2), a letter pattern of "VOID" was gravure printed using a resin solution containing an acrylic resin (an acrylic polymer whose main monomer is methyl methacrylate), and then dried to form a pattern layer having a thickness of 5 μm. The area ratio of the pattern layer to the area of the support surface on the side on which the pattern layer was formed was 38%.

(3) Preparation of Laminate (M1) Next, an ultraviolet-curable ink (manufactured by T&K TOKA Corporation, product name "UV161 Red S") was gravure-printed on the entire surface of the support on which the pattern layer was formed to form an ink coating film, and the coating film was cured by irradiating it with ultraviolet rays from a high-pressure mercury lamp to form a first coating layer (X1) having a thickness of 1 μm, thereby preparing a laminate (M1).

(4) Preparation of Peel Detection Label The exposed surface of the first coating layer (X1) of the laminate (M1) prepared in (3) above was laminated to the exposed surface of the second coating layer (X2) of the laminate (M2) prepared in Production Example 4.
In this way, a peel detection label was obtained by directly laminating the support, the pattern layer, the first coating layer (X1), the second coating layer (X2), the base material layer (Y), the adhesive layer (Z), and the release sheet in this order.

The release sheet of the prepared peel detection label was removed, and the adhesive surface of the exposed adhesive layer (Z) was attached to a glass plate (manufactured by NSG Precision, product name "Corning Glass Eagle XG", 150 mm x 70 mm x 2 mm) to prepare a peel detection label with a glass plate. Using this peel detection label with a glass plate, the following physical properties were measured by the following methods. The results are shown in Table 1.

[Concealment rate of peeling detection labels]
The concealment rate of the above-mentioned glass plate-attached peel detection label was measured in accordance with JIS K5600-4-1:1999.

[Total light transmittance (Tt), diffuse transmittance (Td), and haze of peel detection label]
The total light transmittance (Tt) and diffuse transmittance (Td) of the above-mentioned glass plate-attached peel detection label were measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "NDH-5000") in accordance with JIS K7361-1:1997.
The haze was calculated from the measured total light transmittance (Tt) and diffuse transmittance (Td) according to the following formula.
Haze (%) = Td / Tt x 100

In addition, the adhesive strength and holding power of the peel detection labels were measured using the following methods, and the pattern expression of the peel detection labels and the presence or absence of adhesive residue were evaluated. The results are shown in Table 1.

[Adhesive strength of peel detection label]
The prepared peel detection label was cut into a size of 200 mm in length (MD) × 25 mm in width (TD) to prepare a test piece. The release sheet of the test piece was removed in an environment of 23°C and 50% relative humidity, and the exposed adhesive surface of the pressure-sensitive adhesive layer (Z) was pressed against a stainless steel plate (SUS304 steel, polished #360) as an adherend by rolling the rubber roll back and forth once using a 2 kg rubber roll, and the test piece was left to stand for 24 hours in the same environment.
After standing for 24 hours, the test piece was peeled from the adherend at a 90° peeling method at a tensile speed of 300 mm/min in accordance with JIS Z0237:2000, and the adhesive strength of the peel detection label was measured.

[Retention power of peel detection label]
The prepared peel detection label was cut into a size of 100 mm length (MD direction) × 25 mm width (TD direction) to prepare a test piece. In an environment of 23°C and 50% relative humidity, the release sheet of the test piece was removed, and the exposed adhesive surface of the adhesive layer (Z) was pressed against a stainless steel plate (SUS304 steel, polished #360) as an adherend by rolling the rubber roll back and forth five times using a 2 kg rubber roll so that the applied surface was 25 mm length (MD direction) × 25 mm width (TD direction), and the rubber roll was left to stand for 20 minutes in the same environment.
After leaving it for 20 minutes, it was transferred to a thermostatic chamber at a temperature of 40°C, and a 1 kg weight was attached so that a load was applied vertically to the peel detection label, and the time (seconds) elapsed until the test piece slipped off and completely peeled off from the adherend was measured. The longer the elapsed time, the better the retention strength of the peel detection label. If the test piece did not peel off from the adherend even after 70,000 seconds had passed, the test was terminated. In this case, "70,000 NC" was entered in the retention strength column of Table 1.

[Evaluation of Pattern Distinguishing before Peeling]
Before the measurement of the adhesive strength, the test piece was visually observed from the support side, and the pattern distinguishability before peeling was evaluated based on the following criteria.
A: The word "VOID" on the pattern layer could not be confirmed even when observed from any angle.
B: The word "VOID" on the pattern layer cannot be seen when viewed from the front, but can be seen when observed from an oblique direction.
C: The word "VOID" on the pattern layer could be seen when viewed from the front.

[Evaluation of pattern expression after peeling]
After the above-mentioned adhesive strength measurement, the test piece peeled from the adherend was visually observed from both the support side and the adhesive layer (Z) side, and the pattern development was evaluated based on the following criteria.
A: The word "VOID" on the pattern layer was confirmed by observing both the support side and the pressure-sensitive adhesive layer (Z) side.
B: The word "VOID" on the pattern layer could not be confirmed when observed from the support side, but could be confirmed when observed from the pressure-sensitive adhesive layer (Z) side.
C: The word "VOID" on the pattern layer could not be confirmed by observation of either the support side or the pressure-sensitive adhesive layer (Z) side.

[Evaluation of Adhesive Residue on Adherend]
After the adhesive strength measurement, the test piece was peeled off and the surface of the adherend was visually observed and evaluated for the presence or absence of adhesive residue based on the following criteria.
A: No adhesive residue (transfer) was observed on the surface of the adherend.
F: Adhesive residue (transfer) was observed on the surface of the adherend.

From Table 1, it was confirmed that the peel detection labels produced in Examples 1 to 3 had good pattern expression after peeling, and no adhesive residue was found on the adherend, and had performance equivalent to that of the peel detection labels using the resin films of Reference Examples 1 and 2. Furthermore, the peel detection labels of Examples 1 to 3 had no pattern when observed from any direction before peeling, resulting in an appearance similar to that of a normal label.
On the other hand, the peel detection label produced in Comparative Example 1 did not allow the pattern to be confirmed after peeling, resulting in a problem in peel detection.

101, 102, 103 Peel detection label 1 Support 2 Pattern layer 3 Intermediate layer (C)
4 Pressure-sensitive adhesive layer (Z)
5 Coating layer (X)
6. Base material layer (Y)
7 First coating layer (X1)
8 Second coating layer (X2)
10, 11, 12 Adhesive laminate 1a Surface of support on the pattern layer side 2a Surface of pattern layer on the intermediate layer (C) side 10a, 11a, 12a Application surface of adhesive laminate 40 Adherend 50 Voids generated when peeling detection label from adherend

Claims (10)

A peel detection label comprising a laminate having, in this order, a support, a pattern layer formed on a part of a surface of the support, and an adhesive laminate having at least an intermediate layer (C) and an adhesive layer (Z),
The support has at least one paper base layer,
The peel detection label has a concealment rate of 75.0% or less as measured in accordance with JIS K5600-4-1:1999. The peel detection label according to claim 1, wherein the breaking strength of the support at 23°C is 30 to 500 MPa. The peel detection label according to claim 1 or 2, wherein the tensile modulus of the support at 23°C is less than 50 MPa or more than 1000 MPa. The peel detection label according to claim 1 or 2, wherein the thickness of the support is 10 to 150 μm. The peel detection label according to claim 1 or 2, wherein the beating degree of the support measured in accordance with JIS P8121-1:2012 is 20 mL or more. The peel detection label according to claim 1 or 2, wherein the haze of the peel detection label is 40% or more. The peel detection label according to claim 1 or 2, wherein the total light transmittance (Tt) of the peel detection label is 30% or more. The peel detection label according to claim 1 or 2, wherein the difference (|Td-Tt|) between the total light transmittance (Tt) and the diffuse transmittance (Td) of the peel detection label is 0.10 to 30.0%. The peel detection label according to claim 1 or 2, wherein the support has a basis weight of 20 to 120 g/ ^m2 . The peel detection label according to claim 1 or 2, in which, after the adhesive layer (Z) of the peel detection label is affixed to an adherend, when it is peeled off from the adherend, interfacial peeling occurs between the support and the pattern layer, making it possible to visually detect whether the peel detection label has been peeled off.