JP2021080312A - Adhesive film - Google Patents

Abstract

To provide an adhesive film which can record information on an adherend itself together with the adhesive film by irradiation with laser light.SOLUTION: The adhesive film of the present invention includes a base material 12 and an adhesive layer 10 containing a discoloring agent discolored by the irradiation with the laser light, and is configured so that at least a part of a portion 11 discolored by the irradiation with the laser light is transferred to the adherend. The adhesive layer is preferably a re-peelable adhesive layer. The adhesive layer preferably contains at least one chemical compound selected from the group consisting of a bismuth-based compound, a molybdenum-based compound and a copper-based compound as the discoloring agent. The content of the discoloring agent in the adhesive layer is preferably 0.5% by mass or more and 50% by mass or less.SELECTED DRAWING: Figure 2

Description

The present invention relates to an adhesive film.

Various information such as logos, products, producer information, serial numbers, management information, etc. are printed on labels and the like, and the labels and the like are affixed to the target product as an adherend. A laser marker label that prints with laser light (laser marking) is used for the label on which such various information is printed because it enables fine printing (see, for example, Patent Document 1). ).

However, in the past, when the label was peeled off from the adherend, the recorded information became unknown, and even the fact that the information was recorded was sometimes unknown.

On the other hand, it may be necessary to manage the information recorded on the adherend of the target product or the like as a copy, but if the information is recorded separately, there is a possibility that the information is disguised.

Japanese Unexamined Patent Publication No. 2009-083185

An object of the present invention is to provide an adhesive film capable of recording information not only on the adhesive film but also on the adherend itself by irradiating the laser beam.

Such an object is achieved by the present invention described in the following (1) to (5).
(1) Base material and
It is provided with an adhesive layer containing a discoloring agent that discolors when irradiated with laser light.
An adhesive film characterized in that at least a part of a portion discolored by irradiation with a laser beam is transferred to an adherend.

(2) The pressure-sensitive adhesive film according to (1) above, wherein the pressure-sensitive adhesive layer is a removable pressure-sensitive adhesive layer.

(3) The pressure-sensitive adhesive film according to (1) or (2) above, wherein the pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive.

(4) The above-mentioned (1) to (3), wherein the pressure-sensitive adhesive layer contains at least one compound selected from the group consisting of a bismuth-based compound, a molybdenum-based compound, and a copper-based compound as the discoloring agent. Adhesive film according to any.

(5) The pressure-sensitive adhesive film according to any one of (1) to (4) above, wherein the content of the discoloring agent in the pressure-sensitive adhesive layer is 0.5% by mass or more and 50% by mass or less.

According to the present invention, it is possible to provide an adhesive film capable of recording information not only on the adhesive film but also on the adherend itself by irradiating the laser beam.

It is a schematic vertical sectional view which shows the structure of 1st Embodiment of the adhesive film of this invention. It is a schematic vertical sectional view which shows the state at the time of laser light irradiation with respect to the adhesive film which concerns on 1st Embodiment. It is a schematic vertical sectional view which shows the state which peeled off the adhesive film which concerns on 1st Embodiment from an adherend after irradiation with a laser beam. It is a schematic vertical sectional view which shows the structure of 2nd Embodiment of the adhesive film of this invention. It is a schematic vertical sectional view which shows the state at the time of laser light irradiation with respect to the adhesive film which concerns on 2nd Embodiment. It is a schematic vertical sectional view which shows the state which peeled off the adhesive film which concerns on 2nd Embodiment from an adherend after irradiation with a laser beam.

Hereinafter, preferred embodiments of the present invention will be described in detail.
[Adhesive film]
First, the adhesive film of the present invention will be described.

<< First Embodiment >>
FIG. 1 is a schematic vertical sectional view showing the configuration of the first embodiment of the pressure-sensitive adhesive film of the present invention, and FIG. 2 is a schematic view showing a state of the pressure-sensitive adhesive film according to the first embodiment when irradiated with laser light. FIG. 3 is a schematic vertical sectional view showing a state in which the adhesive film according to the first embodiment is peeled off from the adherend after irradiation with a laser beam.

The pressure-sensitive adhesive film 1 includes a base material 12 and a pressure-sensitive adhesive layer 10 containing a discoloring agent that changes color when irradiated with laser light Le. The pressure-sensitive adhesive film 1 is irradiated with laser light Le in a state where the pressure-sensitive adhesive layer 10 is attached to the adherend 20.

In the pressure-sensitive adhesive film 1, the pressure-sensitive adhesive layer 10 contains a discoloring agent that changes color when irradiated with the laser light Le, so that the color-changing portion 11 is a portion that is discolored to the corresponding portion of the pressure-sensitive adhesive layer 10 by irradiating the pressure-sensitive adhesive layer 10 with the laser light Le. Can be formed (see FIGS. 1 and 2). Then, at least a part of the portion discolored by the irradiation of the laser beam Le is transferred to the adherend 20, and the transfer portion 21 is formed on the adherend 20 (see FIGS. 2 and 3). ..

As a result, predetermined information can be recorded on the adherend 20 (laser marking). In particular, even when the adhesive film 1 is peeled off, the transfer unit 21 as a recording unit for recording predetermined information can remain on the adherend 20.

Therefore, for example, even if the adhesive film 1 is unintentionally peeled off from the adherend 20, or if someone maliciously maliciously peels off the adhesive film 1 from the adherend 20, the adhesive film 1 is covered. The predetermined information recorded on the body 20 can be read out.

Further, when the adherend 20 on which the above information is recorded is in a state of not having the adhesive film 1, for example, the adherend 20 is placed in an environment in which the adhesive film 1 is peeled off. It can be determined that the adhesive film 1 has a history, or that someone may have tried to peel off the adhesive film 1 with the intention of tampering with the information recorded on the adherend 20. Can be done. Therefore, for example, the history received by the adherend 20 in the process of distribution or the like can be determined based on the sticking state such as the presence or absence of the adhesive film 1.

Further, the pressure-sensitive adhesive layer 10 is generally more easily plastically deformed than other parts and is less likely to accumulate internal stress. Therefore, for example, even when the volume of the discolorable portion changes due to the discoloration, unintentional deformation of the adhesive film 1 as a whole is prevented, and the durability of the adhesive film 1 is unlikely to decrease.

In addition, the adhesive film can be easily manufactured as compared with the case where other parts of the adhesive film can be discolored. In addition, the layer structure of the adhesive film can be simplified as compared with the case where a discolorable portion is separately provided.

Further, the transfer portion 21 which is the information recorded on the adherend 20 and the discoloration portion 11 which is the information recorded on the pressure-sensitive adhesive layer 10 can be made to correspond to each other. Therefore, for example, when the adhesive film 1 is peeled off from the adherend 20 after irradiation with the laser beam Le, a part of the discolored portion due to the irradiation with the laser beam Le is transferred to the adherend 20, and the laser beam Le If the other part (more specifically, the other part in the thickness direction) of the discolored portion due to the irradiation of the adhesive layer 10 is configured to remain in the pressure-sensitive adhesive layer 10, it is covered after the irradiation with the laser beam Le. The adhesive film 1 (adhesive film 1 having the discolored portion 11) peeled off from the adherend 20 can be used as a copy of the information (transfer portion 21) formed on the adherend 20. Further, by attaching the adhesive film 1 (adhesive film 1 having the discolored portion 11) peeled off from the adherend 20 after irradiation with the laser beam Le to another adherend, information corresponding to a plurality of articles (corresponding information ( Typically, the same information) can be given.

Hereinafter, each configuration constituting the adhesive film 1 will be described in detail.
<Base material>
The base material 12 has a function of supporting the pressure-sensitive adhesive layer 10.

When the discoloration portion 11 and the transfer portion 21 are formed by a method as described with reference to FIG. 2, the constituent material of the base material 12 is not particularly limited as long as it has light transmittance. For example, polyolefins such as polyethylene, polypropylene and ethylene / propylene copolymers; polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate and polyethylene naphthalate; acetate resins, acrylonitrile-butadiene-styrene copolymer (ABS) resins, polystyrenes, etc. Examples thereof include polyvinyl chloride, polyamide, polyimide, polycarbonate, cellulose acetate and the like, and one or a combination of two or more selected from these can be used, but from the viewpoint of the transparency of visible light and laser light Le, etc. , Polyester, polyolefin, polyvinyl chloride and the like are preferable, and polyethylene terephthalate is more preferable. When the discolored portion 11 and the transfer portion 21 are formed by the method described with reference to FIG. 5 in the second embodiment, the base material 12 is not limited to the one having light transmission. For example, it may be composed of various metal materials and the like.

Further, the base material 12 may contain components other than those described above (other components). Examples of such components include colorants such as dyes and pigments, antioxidants such as anilide and phenol, ultraviolet absorbers such as benzophenone and benzotriazole, light stabilizers, modifiers, and rust preventives. Agents, fillers, surface lubricants, corrosion inhibitors, heat stabilizers, lubricants, antistatic agents, polymerization inhibitors, cross-linking agents, catalysts, plasticizers, leveling agents, thickeners, softeners, dispersants, etc. Be done.

Further, the base material 12 may be made of a single layer or may be a laminated body including a plurality of layers. Further, the base material 12 may be made of, for example, a functionally graded material whose composition changes in a gradient in the thickness direction.

The thickness of the base material 12 is not particularly limited, but is preferably 15 μm or more and 300 μm or less, and more preferably 30 μm or more and 200 μm or less.
The base material 12 preferably has light transmittance.

As a result, the visibility of the pattern by the discolored portion 11 from the surface side on which the base material 12 is provided can be improved. Further, the discolored portion 11 can be suitably formed by irradiating the laser beam Le from the surface side on which the base material 12 is provided.

The transmittance of visible light with respect to the base material 12 is not particularly limited, but is preferably 80% or more, more preferably 90% or more and 100% or less, and 95% or more and 99.99% or less. Is even more preferable.

As a result, the contrast between the discolored portion 11 formed by being discolored by irradiation with the laser beam Le in the adhesive layer 10 and the other portion (non-discolored portion that is not discolored) can be made larger. , The visibility of the pattern by the discolored portion 11 can be further improved.

The transmittance of the laser light Le (laser light Le used for forming the discolored portion 11) with respect to the base material 12 is not particularly limited, but is preferably 80% or more, more preferably 90% or more and 100% or less. It is preferably 95% or more and 99.99% or less, more preferably.

As a result, when the laser light Le is irradiated from the surface side of the adhesive film 1 on which the base material 12 is provided to form the discolored portion 11, the laser light Le irradiated from the base material 12 side can be more efficiently used. The pressure-sensitive adhesive layer 10 can be reached. As a result, the energy efficiency of the formation of the discolored portion 11 by the irradiation of the laser light Le can be further improved. Further, the contrast between the discolored portion 11 formed by being discolored by irradiation with the laser beam Le in the adhesive layer 10 and the other portion (non-discolored portion that is not discolored) can be made larger. The visibility of the pattern by the discolored portion 11 can be further improved.

<Adhesive layer>
The pressure-sensitive adhesive layer 10 is a portion that comes into contact (adhesion) with the adherend 20 when the pressure-sensitive adhesive film 1 is attached to the adherend 20.

Further, the pressure-sensitive adhesive layer 10 is a layer on which various information is recorded by discoloring the portion irradiated with the laser beam Le to form the discolored portion 11. Further, the pressure-sensitive adhesive layer 10 is configured so that at least a part of the portion discolored by irradiation with the laser beam Le is transferred to the adherend 20 and the transfer portion 21 can be formed on the adherend 20. ..

In addition, in this specification, "discoloration" means changing from the color tone before irradiating laser light Le. A typical example of discoloration is the case where the color changes from a state other than black (including colorless) to black.

Normally, the transfer portion 21 is formed near the surface of the adherend 20 to which the adhesive film 1 is attached, but may be formed inside the adherend 20 by permeation or the like.

The pressure-sensitive adhesive layer 10 may be a re-peelable type pressure-sensitive adhesive layer that is supposed to be peeled off after the pressure-sensitive adhesive film 1 is attached to the adherend 20 in a normal usage pattern, or may be a strong adhesive layer. It may be a re-peelable adhesive, such as one that is designed to easily leave adhesive residue when trying to peel off from the type or adherend 20, although it may not be supposed to be peeled off. It is preferably a layer.

As a result, it is possible to prevent undesired adhesive residue or the like from being generated when the adhesive film 1 is peeled from the adherend 20.

(Adhesive)
Examples of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 10 include acrylic-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, synthetic rubber-based pressure-sensitive adhesives, natural rubber-based pressure-sensitive adhesives, and the like. Adhesives are preferred.

As a result, the adhesiveness between the pressure-sensitive adhesive layer 10 and the base material 12 can be made higher. Further, the carbonization reaction by irradiation of the laser beam Le near the interface between the pressure-sensitive adhesive layer 10 and the adherend 20 can be suitably promoted, and the transfer portion 21 can be more preferably formed on the adherend 20. .. In addition, the transparency of the pressure-sensitive adhesive can be made higher. As a result, when the pressure-sensitive adhesive layer 10 contains white particles as described later, the effect of the effect is more remarkable, and when observing the pressure-sensitive adhesive film 1 provided with the discolored portion 11, the pressure-sensitive adhesive film 1 The contrast between the portion where the discolored portion 11 is provided and the portion other than the portion is increased, and the visibility of the recorded information is improved.

Acrylic adhesives include acrylic acid, methacrylic acid (hereinafter, these are collectively referred to as "(meth) acrylic acid") or ester compounds thereof (acrylate, methacrylate (hereinafter, these are collectively referred to as "(meth)"). It may also be referred to as "acrylate" as long as it contains a (meth) acrylic acid derivative such as)) as a monomer component, and may contain a monomer component other than the above.

In particular, acrylic pressure-sensitive adhesives include, for example, (meth) acrylic acid ester homopolymers, copolymers containing two or more (meth) acrylic acid ester units, and (meth) acrylic acid esters and other components as main components. Those containing at least one selected from copolymers with functional monomers (hereinafter, also simply referred to as "acrylic polymer") are preferably used. Examples of the (meth) acrylic acid ester include (meth) acrylic acid butyl ester, (meth) acrylic acid pentyl ester, (meth) acrylic acid hexyl ester, (meth) acrylic acid heptyl ester, and (meth) acrylic acid octyl. Examples thereof include esters, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic acid nonyl ester, and (meth) acrylic acid decyl ester. Examples of the functional monomer include (meth) acrylic acid hydroxyethyl ester, (meth) acrylic acid hydroxypropyl ester, (meth) acrylic acid, (meth) acrylamide, and dimethyl (meth) acrylamide. .. Acrylic pressure-sensitive adhesives are generally classified into solvent type and emulsion type, and solvent type includes the acrylic polymer, solvent, cross-linking agent, and tackifier, plasticizer, and antistatic agent usually used as desired. It is composed of an ultraviolet absorber and the like, and as the cross-linking system, methylol group condensation, ion cross-linking, urethane cross-linking, epoxy cross-linking and the like are used. On the other hand, the emulsion type is usually composed of the acrylic polymer, an emulsifier, an aqueous solvent, a tackifier used as desired, and the like.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 10 preferably contains a cross-linked pressure-sensitive adhesive crosslinked by a cross-linking agent.

As a result, the cohesive force of the pressure-sensitive adhesive layer 10 can be made more excellent, and the adhesive residue when peeling from the adherend 20 can be more effectively prevented.

Examples of the cross-linking agent (particularly, the cross-linking agent in acrylic pressure-sensitive adhesives) include polyimine compounds such as aliphatic isocyanate compounds, aromatic isocyanate compounds, epoxy compounds, metal chelate compounds, and aziridine compounds, melamine resins, urea resins, and di. Alaldehydes, methylol polymers, metal alkoxides, metal salts and the like can be used. More specifically, for example, an aliphatic isocyanate compound such as hexamethylene diisocyanate (HMDI) or a derivative thereof, an aluminum chelate compound such as aluminum-isopropyrate, aluminum-sec butyrate, aluminum acetylacetonate, or tetraisopropyl titanate. Examples thereof include metal chelate compounds such as titanium chelate compounds such as tetrakis (2-ethylhexoxy) titanate.

The content of the cross-linking agent component in the pressure-sensitive adhesive is not particularly limited, but is preferably 0.01 part by mass or more and 7.5 parts by mass or less with respect to 100 parts by mass of the polymer component of the pressure-sensitive adhesive main agent. It is more preferably 6.5 parts by mass or less, and further preferably 3 parts by mass or more and 6 parts by mass or less.

As a result, an appropriate adhesive force can be obtained by re-peeling, and it is possible to more effectively prevent the generation of adhesive residue when peeling from the adherend 20.

(Discoloring agent)
The discoloring agent is a component that discolors when irradiated with laser light Le, and is a component that contributes to forming the discoloring portion 11 on the pressure-sensitive adhesive layer 10.

The discoloring agent includes, for example, a substance that develops (discolors) the discoloring agent itself by a chemical reaction (for example, an oxidation reaction, a reduction reaction, etc.) by the action of the laser light Le when irradiated with the laser light Le, and the pressure-sensitive adhesive layer 10. A substance or the like in which the resin composition around the discoloring agent (for example, the resin material (adhesive) constituting the pressure-sensitive adhesive layer 10) chemically reacts (for example, carbonizes) to develop color (discoloration) can be preferably used.

The discoloring agent may be in a dispersed state or in a dissolved state in the pressure-sensitive adhesive layer 10.

Examples of the discoloring agent include copper compounds, molybdenum compounds, bismuth compounds, iron compounds, nickel compounds, chromium compounds, zirconium compounds, neodymium compounds, antimony compounds, titanium compounds, and mica compounds. , Tin compounds and the like.

Among these, the pressure-sensitive adhesive layer 10 preferably contains at least one compound selected from the group consisting of bismuth-based compounds, molybdenum-based compounds, and copper-based compounds as a discoloring agent.

As a result, the color-developing property of the pressure-sensitive adhesive layer 10 at the time of laser light Le irradiation can be made more excellent, and the transfer portion 21 can be more preferably formed on the adherend 20. Further, it is possible to more effectively prevent unintentional swelling of the pressure-sensitive adhesive layer 10 due to laser light Le irradiation and deterioration of the adhesiveness between the pressure-sensitive adhesive layer 10 and the base material 12. Therefore, the visibility of the discolored portion 11 and the reliability of the adhesive film 1 can be further improved, and the visibility and durability of the transfer portion 21 can be further improved.

The content of the discoloring agent in the pressure-sensitive adhesive layer 10 is not particularly limited, but is preferably 0.5% by mass or more and 50% by mass or less, and 1.0% by mass or more and 3.0% by mass or less. More preferred.

As a result, the color development property of the pressure-sensitive adhesive layer 10 can be made more excellent while fully exerting the functions of the components other than the color-changing agent in the pressure-sensitive adhesive layer 10, and the visibility, durability and the like can be improved. An excellent transfer portion 21 can be more preferably formed. In addition, it is possible to more effectively prevent unintentional denaturation, deterioration, etc. of the adhesive film 1 during laser light Le irradiation.

The color of the discolored portion 11 is not particularly limited, but is preferably a dark color.
Specifically, the chromaticity diagram ^{of the L * value (L *} a ^* b ^* display defined by JIS Z8781-4) at the portion where the discolored portion 11 is provided when observed from the surface side of the pressure-sensitive adhesive layer 10. The value of L ^* in (1) is preferably 0 or more and 60 or less, and more preferably 0 or more and 40 or less.

As a result, in general, the color difference between the discolored portion 11 and the non-discolored portion can be increased, and the visibility of the discolored portion 11 can be further enhanced. In particular, when the pressure-sensitive adhesive layer 10 contains white particles, the difference in brightness between the discolored portion 11 and the non-discolored portion can be increased, the contrast can be increased, and the visibility of the discolored portion 11 can be further enhanced. Further, the dark color changing portion 11 as described above can be suitably formed by using the color changing agent described above.

(White particles)
The pressure-sensitive adhesive layer 10 may contain white particles.

As a result, the whiteness in the state where the discolored portion 11 is not formed and the portion where the discolored portion 11 is not formed is increased, the contrast between the discolored portion 11 and the non-discolored portion is improved, and the pattern by the discolored portion 11 is formed. The visibility can be further improved.

White particles are generally less susceptible to laser light Le.
Examples of such white particles include white pigments and the like, and specific examples thereof include titanium oxide (TiO ₂ ), zinc oxide, zirconium oxide, calcium carbonate, zinc sulfide, barium sulfate and the like.

Among them, the white particles preferably contain at least one of titanium oxide and calcium carbonate.

As a result, the whiteness and stability of the white particles can be made more excellent, and the above-mentioned effects can be more stably and more prominently exhibited.

The average particle size of the white particles is preferably 0.2 μm or more and 0.4 μm or less, and more preferably 0.2 μm or more and 0.3 μm or less.
As a result, the above-mentioned effect is more prominently exhibited.

The content of the white particles in the pressure-sensitive adhesive layer 10 is preferably 0.1% by mass or more and 30% by mass or less, and more preferably 0.2% by mass or more and 25% by mass or less.

As a result, the functions of the other components in the pressure-sensitive adhesive layer 10 can be fully exerted, and the effect of containing the white pigment as described above can be more prominently exerted.

(Plasticizer)
The pressure-sensitive adhesive layer 10 may contain a plasticizer.

Thereby, the flexibility of the pressure-sensitive adhesive layer 10 can be made more excellent. Further, the removability of the pressure-sensitive adhesive layer 10 can be made more excellent, and the operability when the pressure-sensitive adhesive layer 10 is peeled off from the adherend 20 can be made more excellent. In addition, the components of the pressure-sensitive adhesive layer carbonized by irradiation with laser light Le can be suitably transferred to the adherend 20.

Examples of the plasticizer include phthalate ester-based plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, di-n-octyl phthalate, and dicyclohexyl phthalate, trioctyl trimellitic acid, and trimellitic acid. Trimellitic acid ester plasticizers such as triisononyl acid, triisodecyl trimellitic acid, 2-ethylhexyl trimellitic acid, polyester plasticizers such as phthalic acid polyester, triclezyl phosphate, trioctyl phosphate, triphenyl phosphate and the like Examples thereof include acid ester-based plasticizers, epoxidized linseed oil, and epoxidized plasticizers such as butyl epoxidized stearate.

The content of the plasticizer in the pressure-sensitive adhesive layer 10 is not particularly limited, but is preferably 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the pressure-sensitive adhesive, and is 5 parts by mass or more and 25 parts by mass or less. Is more preferable.

If the content of the plasticizer is too low, the effect of containing the plasticizer as described above may not be sufficiently exhibited depending on the type of the plasticizer and the like. Further, if the content of the plasticizer is too high, the flexibility of the pressure-sensitive adhesive layer 10 may become excessive.

(Other ingredients)
Further, the pressure-sensitive adhesive layer 10 may contain components (other components) other than those described above. Examples of such components include tackifiers, dyes, colorants such as pigments, antioxidants such as anilides and phenols, ultraviolet absorbers such as benzophenone and benzotriazole, light stabilizers, and modifications. Agents, rust inhibitors, fillers, surface lubricants, corrosion inhibitors, heat stabilizers, lubricants, antistatic agents, polymerization inhibitors, cross-linking agents, catalysts, leveling agents, thickeners, softeners, dispersants, etc. Can be mentioned.

The content of these components is not particularly limited, but it is preferable that the content of these components as a whole does not exceed 10% by mass.

The pressure-sensitive adhesive layer 10 may have a uniform composition at each site, or may have sites having different compositions. For example, the discoloring agent may be unevenly distributed near the surface of the pressure-sensitive adhesive layer 10 (the surface in contact with the adherend 20) in the thickness direction of the pressure-sensitive adhesive layer 10. In this case, for example, in the production of the pressure-sensitive adhesive film 1, a composition containing a discoloring agent (for example, a coating liquid) is applied to the surface of the pressure-sensitive adhesive layer once formed to form the pressure-sensitive adhesive film 1, and the final pressure-sensitive adhesive layer 10 is also formed. Good. Further, for example, the white particles are unevenly distributed near the surface of the pressure-sensitive adhesive layer 10 (the surface in contact with the adherend 20) or near the contact surface side with the base material 12 in the thickness direction of the pressure-sensitive adhesive layer 10. You may be doing it.

The thickness of the pressure-sensitive adhesive layer 10 is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less.

As a result, the ease of handling of the adhesive film 1 such as the ease of attachment when the adhesive film 1 is attached to the adherend 20 can be further improved, and the pattern can be visually recognized by the discolored portion 11. The sex can be further improved. Further, the color densities of the discolored portion 11 and the transfer portion 21 can both be made higher, and the visibility of the information formed on the adhesive film 1 and the adherend 20 can be made more surely excellent. It is advantageous on.

Before the adhesive film 1 is attached to the adherend 20, the contact surface with the adherend 20 (the adhesive layer 10 in the present embodiment) may be covered with a release liner.

As a result, the adhesive film 1 (contact surface with the adherend 20) can be suitably protected during transportation, storage, and the like of the adhesive film 1.

The release liner is not particularly limited, and a liner usually used in the field of adhesive film can be used. Examples of the release liner include those provided with a release layer on the surface of a paper base material or a film base material.

Examples of the paper base material include papers such as high-quality paper, kraft paper, and glassine paper. Examples of the film base material include films made of various resins such as polyethylene terephthalate, polyethylene, and polypropylene. The paper base material and the film base material may contain a filler such as a filler.

Examples of the constituent material of the release layer include silicone, long-chain alkyl-based resin, and fluororesin.

The thickness of the release liner is not particularly limited, but is preferably 10 μm or more and 150 μm or less, and more preferably 20 μm or more and 130 μm or less.

The adherend 20 to which the adhesive film 1 of the present embodiment is attached is not particularly limited, and may be made of any material, and may have any shape and size. ..

[Laser marking]
The adhesive film 1 records predetermined information by irradiating laser light Le to form a discolored portion 11 at the corresponding portion of the adhesive layer 10, and at the same time, the transfer portion 21 is formed at the corresponding portion of the adherend 20. The predetermined information is recorded by forming the (laser marking).

Examples of the laser light Le used for recording information include a semiconductor laser, a YAG laser, a He-Ne laser, a CO ₂ laser, a YVO ₄ laser, and the like, and among them, the YAG laser is preferable.

As a result, the discolored portion 11 and the transfer portion 21 can be easily and surely formed, and unintentional modification and deterioration of the base material 12, the adhesive layer 10, the adherend 20 and the like can be more preferably prevented. be able to.

The content of the information recorded by the laser marking is not particularly limited, and may be, for example, various characters, symbols, signs, points, lines, figures, patterns, or any combination thereof, and the content of the information is It is optional and may be anything.

For example, the same content may be recorded on a plurality of pressure-sensitive adhesive films 1, or different information may be recorded for each pressure-sensitive adhesive film 1 for individual identification, such as serial numbers and product information.
The information may be a two-dimensional code such as a bar code.

<< Second Embodiment >>
FIG. 4 is a schematic vertical cross-sectional view showing the configuration of the second embodiment of the pressure-sensitive adhesive film of the present invention, and FIG. 5 is a schematic vertical section showing a state of the pressure-sensitive adhesive film according to the second embodiment when irradiated with laser light. FIG. 6 is a schematic vertical sectional view showing a state in which the adhesive film according to the second embodiment is peeled off from the adherend after irradiation with laser light. In the following description, the differences from the above-described embodiment will be mainly described, and the description of the same matters will be omitted.

The pressure-sensitive adhesive film 1 of the present embodiment is provided between the base material 12, the pressure-sensitive adhesive layer 10 containing a discoloring agent that changes color by irradiation with laser light Le, and the base material 12 and the pressure-sensitive adhesive layer 10, and reflects light. It has a reflective layer 13 having a function of In other words, the reflective layer 13 is provided on the surface side of the adhesive film 1 opposite to the surface in contact with the adherend 20.

With such a configuration, when the adherend 20 has the transparency of the laser beam Le, even if the base material 12 does not have the light transmittance, as shown in FIG. 5, the adherend By irradiating the laser beam Le from the 20 side, the discolored portion 11 and the transfer portion 21 can be preferably formed. That is, when irradiating the laser light Le for the formation of the discoloration portion 11 and the transfer portion 21, a part of the irradiated laser light Le is not absorbed by the pressure-sensitive adhesive layer 10, but the reflection layer 13 is arranged. As a result, the unabsorbed laser light Le is reflected by the reflection layer 13 (see FIG. 5). As a result, the reflected laser light Le can contribute to the formation of the discoloration portion 11 and the transfer portion 21. Therefore, it is possible to increase the proportion of the components that contribute to the formation of the discolored portion 11 and the transfer portion 21 in the energy of the irradiated laser beam Le. Therefore, the discolored portion 11 and the transfer portion 21 can be formed with a smaller energy, and the discolored portion 11 and the transfer portion 21 having a larger degree of discoloration with a laser beam Le of a predetermined energy amount are more durable. The transfer portion 21 can be formed. Further, even when the light transmission of the base material 12 is low or the base material 12 has low resistance to laser light Le, the discolored portion 11 and the transfer portion 21 can be preferably formed. , The range of selection of the constituent materials of the base material 12 and the like can be expanded. For example, a base material 12 composed of various paper materials, non-woven fabrics, woven fabrics, and the like can be preferably used. As a result, the width of the structure of the adhesive film 1 as a whole can be expanded.

When the pressure-sensitive adhesive film 1 has a reflective layer 13 as in the present embodiment, when observing the discolored portion 11 of the pressure-sensitive adhesive film 1 peeled off from the adherend 20, usually, the surface side of the pressure-sensitive adhesive layer 10 is observed. Will be observed from.

Further, in such a case, when observing the adherend 20 on which the transfer portion 21 is formed from the surface side on which the transfer portion 21 is provided, the adhesive film is observed from the surface side of the adhesive layer 10 as described above. An inversion (mirror image relationship) pattern is observed with respect to the information in the case of.

<Reflective layer>
The reflective layer 13 may have a function of reflecting light, but is preferably a light-colored layer having a higher brightness than the discolored portion 11 formed by irradiation with the laser light Le.

As a result, in the adhesive film 1 peeled from the adherend 20, the visibility of the pattern by the discolored portion 11 can be further improved, and the energy efficiency when forming the discolored portion 11 by irradiating the laser beam Le is performed. Can be further improved.

Further, the reflective layer 13 is preferably a light-colored layer having a higher brightness than the transfer portion 21 formed by irradiation with the laser light Le.

This makes it easy to determine whether or not the transfer unit 21 has a sufficient color density in the process of laser marking, and if the color density is insufficient, adjustments such as additional irradiation with laser light Le are performed. Becomes easier.

In particular, when the reflective layer 13 exhibits a white color, the above effects are more prominently exhibited.

Such a reflective layer 13 can be made of, for example, a material containing a colorant. Specifically, it can be composed of a material containing a colorant and a binder (binder resin). The colorant is not particularly limited, but is preferably one that exhibits a bright color having a higher brightness than the discolored portion 11 and the transfer portion 21.
As a result, the same effect as described above is exhibited.

Examples of the reflective material constituting the reflective layer 13 include various metals, white-based colorants such as inorganic pigments exhibiting white color, and organic pigments.

Examples of the white inorganic pigment include zinc carbonate, zinc oxide, zinc sulfide, talc, kaolin, calcium carbonate, titanium oxide, silica, lithium fluoride, calcium fluoride, barium sulfate, alumina, zirconia, calcium phosphate, mica and the like. Can be mentioned.

Examples of the organic pigment exhibiting white color include polystyrene, polyvinyl chloride, polyethylene, polypropylene, polyvinylidene chloride, and poly (meth) acrylate copolymers.

The reflective layer 13 may be, for example, a film formed by a vapor phase film forming method (for example, a vapor-deposited film or the like), or a composition containing a light-reflecting material and a binder may be layered by coating or the like. It may be molded.

When the reflective layer 13 is a metal layer made of a metal material, the thickness of the reflective layer 13 is preferably 0.01 μm or more and 5.0 μm or less.

The reflective layer 13 may contain components other than those described above (other components). Examples of such components include binders, tackifiers, colorants other than white colorants, antioxidants such as anilide and phenol, ultraviolet absorbers such as benzophenone and benzotriazole, and light stabilizers. , Modifiers, rust inhibitors, fillers, surface lubricants, corrosion inhibitors, heat stabilizers, lubricants, antistatic agents, polymerization inhibitors, cross-linking agents, catalysts, plasticizers, leveling agents, thickeners, softening Examples include agents and dispersants.

The reflectance of visible light (for example, the reflectance of laser light Le) with respect to the reflective layer 13 is not particularly limited, but is preferably 30% or more and 100% or less, and more preferably 50% or more and 100% or less. It is preferable, and it is more preferably 70% or more and 100% or less.

As a result, the effect of providing the reflective layer 13 as described above is more prominently exhibited.

<Second adhesive layer>
Further, in the configuration shown in FIG. 4, a second pressure-sensitive adhesive layer 14 is provided between the base material 12 and the reflective layer 13.

Thereby, for example, even when the reflective layer 13 does not have adhesiveness, the adhesion between the base material 12 and the reflective layer 13 can be made excellent. Further, in the production of the pressure-sensitive adhesive film 1, the degree of freedom in the formation order of each layer is increased.

Examples of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 14 include the pressure-sensitive adhesive exemplified as a component of the above-mentioned pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer) 10.

The second pressure-sensitive adhesive layer 14 may contain components (other components) other than those described above. Examples of such components include tackifiers, colorants other than white colorants, antioxidants such as anilide and phenol, ultraviolet absorbers such as benzophenone and benzotriazole, light stabilizers, and modifications. Pawnbrokers, rust inhibitors, fillers, surface lubricants, corrosion inhibitors, heat stabilizers, lubricants, antistatic agents, polymerization inhibitors, cross-linking agents, catalysts, plasticizers, leveling agents, thickeners, softeners, Dispersants and the like can be mentioned.

The thickness of the second pressure-sensitive adhesive layer 14 is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less.

Thereby, the ease of handling of the adhesive film 1 such as the ease of attachment when the adhesive film 1 is attached to the adherend 20 can be further improved.

The adherend 20 to which the adhesive film 1 of the present embodiment is attached is not particularly limited as long as at least the portion to which the adhesive film 1 is attached has light transmittance.

Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto.

For example, the pressure-sensitive adhesive film of the present invention may further include a configuration other than those described above. For example, the pressure-sensitive adhesive film of the present invention may include a coat layer (for example, a coat layer for printing) and an intermediate layer.

Further, in the above-described first embodiment, the case of irradiating the laser beam from the surface side of the base material of the adhesive film (the surface side opposite to the adhesive layer) has been described, but the adherend transmits the laser beam. In the case of having a property, laser light may be irradiated from the surface side of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film via the adherend, as described in the second embodiment. In such a case, when the base material has the reflectivity of the laser light when the base material is irradiated with the laser light from the pressure-sensitive adhesive layer side (more specifically, the entire base material is made of a light-reflecting material. In the case, when the surface of the base material facing the pressure-sensitive adhesive layer is made of a light-reflecting material, the base material has a layer made of a light-reflecting material and is closer to the pressure-sensitive adhesive layer than the layer. When only a layer having light transmittance is provided in the above), the same effect as that of the second embodiment described above can be obtained.

1 ... Adhesive film 10 ... Adhesive layer (first adhesive layer)
11 ... Discolored part 12 ... Base material 13 ... Reflective layer 14 ... Second adhesive layer 20 ... Adhesive 21 ... Transfer part Le ... Laser light

Claims (5)

With the base material
It is provided with an adhesive layer containing a discoloring agent that discolors when irradiated with laser light.
An adhesive film characterized in that at least a part of a portion discolored by irradiation with a laser beam is transferred to an adherend. The pressure-sensitive adhesive film according to claim 1, wherein the pressure-sensitive adhesive layer is a removable pressure-sensitive adhesive layer. The pressure-sensitive adhesive film according to claim 1 or 2, wherein the pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive. The method according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer contains at least one compound selected from the group consisting of a bismuth-based compound, a molybdenum-based compound, and a copper-based compound as the discoloring agent. Adhesive film. The pressure-sensitive adhesive film according to any one of claims 1 to 4, wherein the content of the discoloring agent in the pressure-sensitive adhesive layer is 0.5% by mass or more and 50% by mass or less.

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