JP2021109406A - Laminate and adhesive composition - Google Patents

Abstract

To provide a laminate for laser marking which has a shielding layer having high shieldability against laser light while having a dark color.SOLUTION: There is provided a laminate (100) for laser marking which comprises a shielding layer (1) having high shieldability against laser light and a laser marking layer (3), wherein the shielding layer (1) comprises carbon black and a scaly filler.SELECTED DRAWING: Figure 1

Description

The present invention relates to, for example, a laminate for laser marking and an adhesive composition used for the laminate for laser marking.

A laser marking label is used as a name plate on which various information is described or a label for process control. The laser marking label is a label printed by being irradiated with laser light. The laser marking label is composed of, for example, a laminated body in which two or more layers are laminated on a film. By etching the surface layer of the laminate with laser light to expose the lower layer, information such as characters or barcodes is printed. However, when printing with laser light, the laser light may penetrate the label and damage the adherend, so measures such as thickening the base and providing a shielding layer have been taken.

For example, in Patent Document 1, a white ink layer containing a titanium oxide pigment and a black ink layer containing a carbon pigment are sequentially laminated on one surface of a transparent base material, and the other surface of the transparent base material is composed of light-colored ink. A laminated body for laser marking in which a shielding layer is laminated is described. Such a laminate for laser marking has a black ink layer on the surface, and when laser light is irradiated from the black ink layer side, the black ink layer is scraped off, the white ink layer or the light color ink layer is exposed, and characters and the like are exposed. Display information.

Further, for example, Patent Document 2 describes a laminate for laser marking containing a scaly filler and a white pigment on the surface side of the base film opposite to the side where the laser of the laser coloring layer is irradiated. ing.

Japanese Unexamined Patent Publication No. 2009-119658 (published on June 4, 2009) Japanese Patent No. 6344022 (issued on June 13, 2018)

However, in the laminate for laser marking described in Patent Document 1, when the first layer on the surface is formed of white or light-colored ink, information can be displayed by replacing the white ink layer with a black ink layer. It will be possible. However, the black ink layer has a high ability to absorb laser light and converts light energy into heat. Therefore, when irradiated with laser light, a part of the black ink layer may be scraped off to the extent that the surface of the base material layer is exposed. When the black ink layer is scraped off, the hue contrast between the laser marking layer and the shielding layer made of light-colored ink becomes low, and there is a problem that the information marked on the laminate cannot be read.

The laminate for laser marking described in Patent Document 2 has a shielding layer in which a scaly filler and a white pigment are used in combination. However, if the content of the scaly filler is increased, poor adhesion occurs between the shielding layer and the base material layer, cracks are likely to occur in the shielding layer itself, and there is a problem that sufficient strength cannot be obtained in the shielding layer. be. Further, when the shielding layer is a pressure-sensitive adhesive layer, a decrease in adhesive force and a decrease in cohesive force are likely to occur.

Further, a laminate for laser marking, in which the laser marking layer etched by the laser light is light-colored and the shielding layer of the laser light is dark-colored, is in high demand because information can be displayed by dark-colored characters. However, as described above, the dark-colored shielding layer is easily etched together with the laser marking layer by the laser light, and it is difficult to form a shielding layer having high shielding properties.

In order to solve the above problems, the laminate according to the embodiment of the present invention includes a shielding layer having a shielding property against laser light and a laser marking layer, and the shielding layer includes a resin component, carbon black, and the like. And contains scaly filler.

The pressure-sensitive adhesive composition according to an embodiment of the present invention is a pressure-sensitive adhesive composition for attaching a laminate for laser marking to an adherend, and contains carbon black, a scaly filler, and a resin component. contains.

According to one embodiment of the present invention, it is possible to provide a laminate for laser marking provided with a shielding layer having a high shielding property against laser light while having a dark color, and a related technique thereof.

It is a figure explaining the outline of the laminated body 100 for laser marking which concerns on one Embodiment of this invention. It is a figure which shows typically the state which the laminated body 100 shown in FIG. 1 was etched by a laser beam. It is a figure explaining the outline of the laminated body 101 for laser marking which concerns on one Embodiment of this invention. It is a figure which shows typically the state which the laminated body 101 shown in FIG. 3 was etched by a laser beam. It is a figure explaining the outline of the laminated body 102 for laser marking which concerns on one Embodiment of this invention. It is a figure explaining the outline of the laminated body 103 for laser marking which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.

<Laminated body 100>
FIG. 1 is a diagram schematically showing an example of a layer structure of a laminated body according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing a state in which the laminate shown in FIG. 1 is etched by laser light.

The laminate 100 shown in FIG. 1 is a laminate for laser marking, and is a laminate in which the shielding layer 1, the base material layer 2, and the laser marking layer 3 are laminated in this order. The film layer provided with the base material layer 2 and the laser marking layer (first layer) 3 before the shielding layer 1 is formed is referred to as a laser marking film 10. The shielding layer 1 of the laminated body 100 is a layer having both a shielding property for shielding laser light and an adhesive property to an adherend. The shielding layer 1 is formed on the back surface of the surface of the base material layer 2 provided with the laser marking layer 3. The laminated body 100 is attached to an adherend (not shown) by the adhesive surface 1a of the shielding layer 1 (FIG. 2). As shown in FIGS. 1 and 2, the shielding layer 1 of the laminated body 100 protects the adhesive surface 1a of the shielding layer 1 with the release film F until the laminated body 100 is attached to the adherend. Is preferable.

In the laminate 100 shown in FIG. 1, the hue of the shielding layer 1 facing each other via the base material layer 2 and the hue of the laser marking layer 3 are different from each other. The laminate 100 displays information on the surface 3a of the laminate 100 by the hue contrast between the shielding layer 1 and the laser marking layer 3. In the laminated body 100, the shielding layer 1 is toned to a darker hue than the laser marking layer 3, and the laser marking layer 3 is toned to a lighter hue than the shielding layer 1. In the present specification, the surface of the laser marking layer means a surface irradiated with laser light.

As shown in FIG. 2, when the surface 3a side of the laser marking layer 3 is irradiated with the laser beam B, the pigment and the resin contained in the laser marking layer 3 absorb the laser beam B to generate heat. The resin contained in the laser marking layer 3 is thermally decomposed by this heat, and the thermally decomposed resin and pigment are blown off. As a result, the laser marking layer 3 is machined from the surface 3a until the surface of the base material layer 2 is exposed, whereby the printing portion 10a is formed on the laser marking layer 3. Cutting out the laser marking layer 3 with the laser beam B in this way is called etching.

The laser for etching the laser marking layer (first layer) 3 can be appropriately selected within a range in which the laser reaching from the laser marking layer 3 to the base material layer 2 can be irradiated. Examples of lasers capable of irradiating the laser light include CO ₂ laser, Yb laser, YVO ₄ laser, Nd: YAG laser, excima laser, semiconductor laser, semiconductor excited solid-state laser, Ar laser, N ₂ / Dye laser and HeCd. Includes laser. Among them, the Yb laser, the YVO ₄ laser, and the Nd: YAG laser are referred to as short wavelength lasers. _{Generally, a CO 2} laser, a Yb laser, a YVO ₄ laser, and an Nd: YAG laser are preferable from the viewpoint that the equipment is inexpensive and the handling thereof is relatively easy.

Laser light irradiation can be appropriately performed according to the wavelength of the laser, the output of the laser, the pulse period, and the spot diameter. For example, if the output of the Yb laser is, for example, 13 W, the pulse period is 50 Hz, and the spot diameter (line width is 70 μm), the scanning speed of the laser beam may be 100 to 3000 mm / sec.

When the base material layer 2 is exposed by etching with laser light, the laminate 100 has the hue of the shielding layer 1 from the printed portion 10a formed by scraping the laser marking layer 3 from the surface 3a through the base material layer 2. Is confirmed. More specifically, when the laminate 100 is viewed from the surface 3a side, the dark and dark hue of the shielding layer 1 is displayed inside the printing portion 10a formed by scanning the laser beam B, and the printing portion 10a is displayed. A bright and pale hue due to the laser marking layer 3 is displayed on the surface 3a outside the inside of the surface 3a. Information is displayed on the surface 3a due to the contrast between the shielding layer 1 and the laser marking layer 3 due to different hues and the shape of the printing portion 10a formed by etching from the top view. Here, the information may be any information formed by etching the laser marking layer 3 with the laser beam B, and may be, for example, characters such as hiragana, kanji, and alphanumeric characters, and is a bar code or two-dimensional. It may be information such as a code. By peeling off the release film F, the laminate 100 can attach the laminate 100 (label) having a print to a desired adherend via the shielding layer 1.

In the present specification, the same hue refers to a color difference that is difficult to distinguish visually. For example, a specular meter (manufactured by Konica Minolta Co., Ltd., trade name: CM-3500d) removes specularly reflected light ( The difference between the L values measured by the SCE) method is less than 7, preferably less than 5. Further, in the present specification, the different hues refer to visible color differences, for example, the difference in L value measured by the SCE method with a colorimeter (manufactured by Konica Minolta Co., Ltd., trade name: CM-3500d). 7 or more, preferably 10 or more. Among them, the hue with a lower L value is a dark and dark hue, and the hue with a higher L value is a bright and light hue.

The configuration of each layer included in the following laminate 100 will be described in more detail.

[Shielding layer 1]
The shielding layer 1 contains a scaly filler and carbon black as pigments, and contains a resin component. The scaly filler and carbon black dispersed in the resin component provide the shielding layer 1 with a darker black hue that is darker than the hue of the laser marking layer 3. Further, since the scaly filler and carbon black are contained, the shielding layer 1 has an extremely high laser light shielding property while having a deep black hue.

The film thickness of the shielding layer 1 is in the range of 1 μm or more and 200 μm or less, and more preferably in the range of 5 μm or more and 100 μm or less. When the film thickness of the shielding layer 1 is 5 μm or more, a shielding layer having high shielding properties can be formed, and when the film thickness of the shielding layer 1 is 100 μm or less, the laminated body 100 can be formed on a curved surface of an adherend. It can be attached by appropriately following the unevenness. Further, by setting the film thickness of the shielding layer 1 to 100 μm or less, when the laminated body 100 is attached, the step from the surface of the adherend to the surface 3a of the laminated body 100 can be reduced.

[1] Pigment The shielding layer 1 contains a scaly filler and carbon black as pigments. The carbon black dispersed in the resin component of the shielding layer 1 brings a darker black hue to the shielding layer 1, which is darker than the hue of the laser marking layer 3, and the carbon black and the scaly filler are the laser light in the shielding layer 1. Improves shielding.

[1-1] The content of the scaly filler and the carbon black scaly filler is within the range of 4.5 parts by mass or more and 30 parts by mass or less, assuming that the amount of the resin component contained in the shielding layer 1 is 100 parts by mass. It is preferably contained. When the content of the scaly filler is 30 parts by mass or less, it is possible to prevent the shielding layer 1 from coagulatingly breaking and leaving adhesive residue when the laminated body is peeled from the adherend. Therefore, the laminated body can be suitably reattached. Further, when the scaly filler is contained in an amount of 4.5 parts by mass or more with the amount of the resin component as 100 parts by mass, a shielding layer 1 capable of suitably shielding light from laser irradiation can be obtained.

The scaly filler is preferably a metal oxide-coated filler obtained by coating a scaly filler such as mica with a metal oxide, and the metal oxide coating the scaly filler is, for example, titanium oxide. , Zinc oxide, zirconium oxide, iron oxide, chromium oxide, tin oxide and talc. Examples thereof include scaly metal fillers such as aluminum paste. Other examples of the scaly filler include scaly silica, alumina, glass flakes, and bismuth oxychloride.

The scaly filler is more preferably a titanium oxide-coated mica because it can reflect long-wavelength light such as red light on the shielding layer 1. By including the titanium oxide-coated mica in the shielding layer 1, the reflectance of red light can be lowered, and reading defects can be less likely to occur when reading a one-dimensional code or a two-dimensional code. In addition, the scaly filler may be, for example, mica not coated with a metal oxide, and the mica may be a natural mica or a synthetic mica. Examples of natural mica include muscovite and phlogopite, and examples of synthetic mica include fluorine gold mica, potassium tetrasilicon mica, and sodium tetrasilicon mica.

Further, since the shielding layer 1 contains a scaly filler and carbon black, it is possible to form a layer having a high shielding property while being black. More specifically, carbon black has the property of absorbing laser light and generating heat. Due to this property, the shielding layer containing carbon black promotes combustion and decomposition of the resin, and the laser light easily penetrates the shielding layer. However, by adding, for example, titanium oxide-coated mica as a scaly filler to the shielding layer containing carbon black, the laser beam is reflected by the scaly filler. In addition, a scaly filler is contained in the shielding layer 1 as a non-combustible material, which reduces combustibility. As a result, it is presumed that the shielding layer can suppress heat generation due to absorption of laser light, and can suppress penetration due to combustion and decomposition of the resin. Further, for example, the reflectance of the titanium oxide-coated mica to the laser light having a wavelength of about 1000 to 1100 nm, which is the wavelength of a short-wavelength laser, or _{a wavelength of about 10000 nm to 11000 nm, which is the wavelength of CO 2 laser light, is 100 in an amount that can be added to the resin component.} It is expected to be less than%. However, the inventors of the present application have found that the transmission of the laser beam can be suitably suppressed by absorbing the laser beam with carbon black, and have completed the invention of the present application.

As described above, carbon black can suitably block light having wavelengths in the vicinity of 1000 to 1100 nm and 10000 nm to 11000 nm, but is also excellent in the ability to convert absorbed light energy into heat. Therefore, when a large amount is blended, heat generation promotes combustion and decomposition of the resin. Therefore, the content of carbon black contained in the shielding layer 1 is preferably 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the resin component.

[1-2] Other Colored Pigments The shielding layer 1 contains other colored pigments as long as the effects of the present invention are not impaired and the hue contrast with the laser marking layer (first layer) 3 described later is not impaired. It may be included.

[2] Resin component contained in the shielding layer 1 The shielding layer 1 may contain an acrylic copolymer and a cross-linking agent as a resin component, and may further contain a tackifying resin as a resin component.

The shielding layer 1 may further contain components other than the above resin components as long as the effects of the present embodiment are exhibited. For example, the resin other than the pigment in the shielding layer 1 may be one kind or more, and examples thereof include polyols, urethane resins, and cellulose resins.

[2-1] Acrylic copolymer contained in the shielding layer 1 In the present specification, the "acrylic copolymer" is a polymer having (meth) acrylic acid and a derivative thereof as a monomer, and is a copolymer. "(Meta) Acrylic" means one or both of Acrylic and Methacrylic. In addition, "(meth) acrylate" means one or both of acrylate and methacrylate. Further, "(meth) acrylic monomer" means at least one of acrylic acid, a derivative thereof, methacrylic acid and a derivative thereof. The acrylic copolymer described below reacts with the cross-linking agent and is contained in the shielding layer 1 as a product.

The acrylic copolymer contained in the shielding layer 1 is a (meth) acrylic monomer which is a main monomer component of the acrylic copolymer and a (meth) acrylic monomer having a carboxyl group, or a (meth) having a hydroxyl group. ) It may contain an acrylic monomer or both.

Examples of the (meth) acrylic monomer, which is the main monomer component of the acrylic copolymer, include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and i-propyl (meth). Acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, cyclohexyl (meth) Meta) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, 2-methoxy (meth) acrylate, 2-ethoxy (meth) acrylate, glycidyl (meth) acrylate And tetrahydrofurfuryl (meth) acrylates. These acrylic monomer components may be one kind or more.

Among them, the (meth) acrylic monomer which is the main monomer component of the acrylic copolymer contained in the shielding layer 1 is methyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate. , T-Butyl (meth) acrylate and the like, preferably butyl (meth) acrylate. When used as a pressure-sensitive adhesive composition, it is most preferably n-butyl acrylate.

The ratio of the (meth) acrylic monomer, which is the main monomer component of the acrylic copolymer contained in the shielding layer 1, is 80% by mass or more, more preferably 90% by mass or more. Further, the ratio of the (meth) acrylic monomer, which is the main monomer component of the acrylic copolymer contained in the shielding layer 1, is 80% by mass or more, which is suitable for sticking to the adherend. The adhesive shielding layer 1 can be formed. Further, even if the laser beam B is irradiated as a resin component containing a scaly filler and carbon black, it is possible to form the shielding layer 1 having adhesiveness while preventing decomposition due to heat generation. That is, the shielding layer 1 can be provided with a function as an adhesive layer.

Examples of (meth) acrylic monomers having a carboxyl group include (meth) acrylic acid, crotonic acid, maleic anhydride, fumaric acid, itaconic acid, glutaconic acid and citraconic acid. These monomers may be one kind or more. The ratio of the acrylic monomer having a carboxyl group in the acrylic copolymer is preferably 10% by mass or less.

The acrylic copolymer contained in the shielding layer 1 may contain a (meth) acrylic monomer having a hydroxyl group. By containing the (meth) acrylic monomer having a hydroxyl group, a cross-linking reaction with a cross-linking agent occurs as in the case of containing the (meth) acrylic monomer having a carboxyl group or more.

Examples of (meth) acrylic monomers having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. , 3-Methyl-3-hydroxybutyl (meth) acrylate, 1,3-dimethyl-3-hydroxybutyl (meth) acrylate, 2,2,4-trimethyl-3-hydroxypentyl (meth) acrylate, 2-ethyl- Includes 3-hydroxyhexyl (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, poly (ethylene glycol-propylene glycol) mono (meth) acrylate and pentaerythritol tri (meth) acrylate. The (meth) acrylic monomer having a hydroxyl group may be one kind or more.

In addition, the acrylic copolymer may contain a monomer copolymerizable with the (meth) acrylic monomer as long as the effects of the present invention are not impaired. Examples of the copolymerizable monomer include vinyl esters such as vinyl acetate, vinyl ethers, acrylonitrile, and styrene.

The mass average molecular weight (Mw) of the acrylic copolymer contained in the shielding layer 1 is not limited, but is preferably 5000 or more and 1 million or less. It is preferable that the mass average molecular weight of the acrylic copolymer is 5000 or more from the viewpoint of improving the drying property of the coating liquid composition for forming the shielding layer 1. It is preferable that the mass average molecular weight of the acrylic copolymer is 400,000 or more from the viewpoint of imparting a cohesive force as a pressure-sensitive adhesive layer to the shielding layer 1. It is preferable that the mass average molecular weight of the acrylic copolymer is 1 million or less from the viewpoint of obtaining a coating liquid composition having good workability at the time of coating. Further, it is preferable that the mass average molecular weight of the acrylic copolymer is 800,000 or less from the viewpoint of obtaining a coating liquid composition having good workability at the time of coating. The adhesive shielding layer 1 is preferable from the viewpoint of easily following the unevenness of the adherend.

The mass average molecular weight of the acrylic copolymer can be determined by a standard polystyrene conversion method using gel permeation chromatography (GPC).

The glass transition temperature of the acrylic copolymer is preferably 40 ° C. or higher, preferably 60 ° C. or higher, from the viewpoint of exhibiting good drying properties when the shielding layer is formed by coating the coating liquid composition. More preferably. Further, the glass transition temperature of the acrylic copolymer is preferably 100 ° C. or lower from the viewpoint of obtaining a coating liquid that is easy to handle when formed by coating the coating liquid composition. From another viewpoint, the glass transition temperature of the acrylic copolymer contained in the shielding layer 1 is preferably −60 ° C. or higher from the viewpoint of cohesive force. Further, from the viewpoint of preferably expressing the surface tack on the adhesive surface 1a, the temperature is preferably −20 ° C. or lower. As a result, the shielding layer 1 can be provided with a function (that is, adhesiveness) as an adhesive layer.

The glass transition temperature of the acrylic copolymer can be estimated as the total of the glass transition temperatures according to the mass ratio of the (meth) acrylic monomer which is the monomer of the acrylic copolymer. The approximate value of the glass transition temperature Tg of acrylic acid is calculated by the following formula. In the following formula, Tg _{1 to Tg n} represent the glass transition temperature (K) of each of the (meth) acrylic monomers 1 to n constituting the (meth) acrylic copolymer. Further, in the following formula, w _{1 to w n} represent the ratio of the mass of each monomer to the total mass of the (meth) acrylic monomers 1 to n. n represents the type of (meth) acrylic monomer and is an integer of two or more.

The glass transition temperature Tg of acrylic acid is determined by using the absolute temperature (K), but is expressed in Celsius degree (° C.) in the present specification.

(Meth) glass transition temperature Tg _n of acrylic monomers is determined as a temperature of an inflection point of the DSC curve obtained by measurement under the following conditions using a differential scanning calorimetry (DSC) measurement apparatus.
Differential scanning calorimetry (DSC) measuring device "EXSTAR6000" (manufactured by Seiko Instruments Inc.)
Atmosphere Nitrogen airflow Measurement sample amount 10 mg
Heating rate 10 ° C / min

Typical glass transition temperatures of (meth) acrylic monomers are methyl methacrylate: 103 ° C., n-butyl methacrylate: 21 ° C., butyl acrylate: -57 ° C., 2-hydroxyethyl methacrylate: 55 ° C., 2-hydroxy. Ethyl acrylate: -15 ° C, acrylic acid: 166 ° C, methacrylic acid: 185 ° C and the like.

The resin component contained in the light-shielding layer may contain one or two or more types of acrylic copolymers.

[2-2] Cross-linking agent The cross-linking agent is a cross-linking agent that cross-links the acrylic copolymer. The shielding layer 1 reacts with the carboxyl groups and hydroxyl groups of the acrylic copolymer in the main chain skeleton to produce a crosslinked product of the acrylic copolymer.

[2-2-1] Polyisocyanate The cross-linking agent for the acrylic copolymer is typically polyisocyanate. The polyisocyanate reacts with the carboxyl group and / or the hydroxyl group contained in the acrylic copolymer.

The content of polyisocyanate in the resin component contained in the shielding layer 1 may be determined based on the content of isocyanate groups contained in the polyisocyanate. The equivalent of the isocyanate group with respect to the total amount of the carboxyl group and the hydroxyl group of the acrylic copolymer in the resin component of the shielding layer 1 is preferably 0.1 equivalent or more and 2.0 equivalent or less.

Examples of polyisocyanates include polyether MDIs such as xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), triphenylmethane triisocyanate, and aromatic polyisocyanate compounds such as tolylene diisocyanate (TDI).

Examples of aliphatic or alicyclic isocyanates include hexamethylene diisocyanate (HDI), heptamethylene diisocyanate, isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate (hydrogenated XDI) such as 1,4-cyclohexanebismethylisocyanate. , And hydrogenated diphenylmethane diisocyanate (hydrogenated MDI) such as 4,4-methylenebiscyclohexylisocyanate. From the viewpoint of suppressing discoloration of the shielding layer 1, the polyisocyanate is preferably an aliphatic or alicyclic polyisocyanate.

Examples of polyisocyanates include dimers or trimers of isocyanate compounds. Examples of such polyisocyanates include uretdione or isocyanurates, prepolymers of isocyanate compounds and polyol resins.

In addition, examples of such polyisocyanates include adducts of isocyanates and polyhydric alcohols, urea compounds, and the like. Examples of the polyhydric alcohol include propylene glycol (bifunctional alcohol), butylene glycol (bifunctional alcohol), trimethylolpropane (TMP, trifunctional alcohol), glycerin (trifunctional alcohol) and pentaerythritol (tetrafunctional alcohol). Is included.

Examples of the above-mentioned adduct include an adduct of tolylene diisocyanate and a trifunctional alcohol, an adduct of isophorone diisocyanate and a bifunctional alcohol, and an adduct of isophorone diisocyanate and a trifunctional alcohol.

The polyisocyanate may be a commercially available product.

[2-2-2] Other cross-linking agents Examples of cross-linking agents other than polyisocyanate include melamine-based cross-linking agents, benzoguanamine-based cross-linking agents, urea-based cross-linking agents, metal chelate-based cross-linking agents, organosilane-based cross-linking agents, and epoxies. Includes cross-linking agents and acid anhydride-based cross-linking agents. Examples of melamine-based cross-linking agents include Nicarac (registered trademark) MS-11 and MS-001 (both manufactured by Nippon Carbide Industries Co., Ltd.) and My Coat 715 (manufactured by Nippon Cytec Industries Co., Ltd., "My Coat" is Orne. Kusu Japan Co., Ltd.'s registered trademark) is included.

[2-3] Adhesive-imparting resin The shielding layer 1 preferably contains an adhesive-imparting resin as a resin component. The tackifier resin is also called a tack fire resin. Since the shielding layer 1 contains the adhesiveness-imparting resin, the adhesiveness of the shielding layer is enhanced. Examples of the tackifying resin include terpene-based resins, rosin-based resins, and petroleum-based resins. Further, the tackifying resin is preferably a rosin ester because it has less bleeding to the adhesive surface 1a and has high durability against a solvent.

[2-4] Other components In addition, the shielding layer 1 is, for example, an antioxidant, a stabilizer such as an ultraviolet absorber, a leveling agent, an anti-settling agent, and an antifoaming agent, as long as the effects of the present invention are not impaired. And additives such as surfactants such as wet dispersants, and plasticizers and the like may be contained as other components.

[Base material layer 2]
The base material layer 2 may be optically transparent. “Optically transparent” means, for example, that the transmittance of visible light is 80% or more and the transmittance of laser light is 50% or more. When the transmittance of visible light in the base material layer is sufficiently high, the hue of the shielding layer 1 is sufficiently over the base material layer 2 when the etched laminate (label) is viewed in a plan view from the laser marking layer 3 side. It becomes possible to visually recognize.

Further, regarding the absorption rate of the laser light in the base material layer 2, through holes are formed in the base material layer 2 due to the influence of the shielding layer 1 arranged on the opposite side of the laser marking layer 3 from the base material layer 2 in etching. From the viewpoint of suppressing this, a lower value is preferable. On the other hand, it is preferable that the transmittance of the laser light in the base material layer 2 is high. By increasing the transmittance, it is possible to suppress the reflection and scattering of the laser light on the laser marking layer 3 side of the base material layer 2, so that finer etching can be realized. From such a viewpoint, the transmittance of the laser light in the base material layer 2 may be 50% or more. The above-mentioned light transmission in the base material layer may be uniform in one laminated body, or may be different depending on a portion to be etched.

The shape of the base material layer 2 is not limited. The thickness of the base material layer 2 may be constant, or may have different thicknesses in one laminated body. The base material layer 2 is preferably a resin base material film because it is generally preferable that the laminate (or the label after etching) has flexibility from the viewpoint of increasing the versatility of the label. The thickness of the film is not limited, and can be appropriately determined, for example, from the viewpoint of a range in which the above-mentioned through holes are not formed during etching and handleability. From this point of view, the thickness of the film may be, for example, 25 to 300 μm.

As the resin component contained in the base material layer 2, for example, a material having high transparency can be generally used. Examples of such materials include glass and thermoplastic resins (thermoplastics) such as ester resins, polycarbonate resins, acrylic resins and thermoplastic urethane resins, which are used for film molding. It is preferably a thermoplastic resin. Above all, it is preferable that the base material layer is made of a thermoplastic resin such as an ester resin from the viewpoint of enhancing the versatility of the laminate and from the viewpoint of realizing fine laser marking.

The ester resin is preferably an aromatic ester resin from the viewpoint of suppressing deformation due to heat during laser marking. The aromatic ester-based resin is more preferably a transparent resin from the viewpoint of suppressing deformation due to heat during laser light irradiation.

Examples of aromatic ester resins include polyethylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate and polyethylene naphthalate. Above all, from the above-mentioned viewpoint, the aromatic ester resin is preferably polyethylene terephthalate.

The base material layer 2 may be treated to improve the adhesion to adjacent layers such as the shielding layer 1 and the laser marking layer 3. For example, in the case of the base material layer 2 made of an aromatic ester resin, the base material layer 2 is covered with the laser marking layer 3 on the surface of the base material layer 2 in order to improve the adhesion to the laser marking layer 3. The portion in contact with other layers such as layer 1 may be subjected to a treatment for enhancing adhesion, such as corona treatment or formation of an easy-adhesion coat.

[Laser marking layer 3]
The laser marking layer 3 is a layer that is etched by laser light, and its hue is different from that of the shielding layer 1. The laser marking layer included in the laminate may be referred to as a first layer. As the material of the laser marking layer 3, a known material having an absorption property for laser light can be used. Therefore, in the laser marking layer 3, the continuous phase (for example, the resin component) of the portion irradiated with the laser beam when viewed in a plan view is decomposed by light and heat. Further, the laser marking layer 3 may contain various coloring pigments such as a white pigment at least within a range that does not impair the hue contrast with the shielding layer 1.

The film thickness of the laser marking layer 3 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. By setting the film thickness of the laser marking layer 3 to 20 μm or less, sufficient etching can be performed by irradiation with a laser beam, and printing defects can be prevented. Further, it is possible to avoid excessively increasing the intensity of the laser light in order to penetrate the laser marking layer 3 and prevent an adverse effect on the lower layer. From the viewpoint of sufficiently etching the laser marking layer 3 by irradiation with laser light, the film thickness of the laser marking layer 3 is preferably 20 μm or less, more preferably 15 μm or less, and 10 μm or less. Is even more preferable.

The film thickness of the laser marking layer 3 is preferably 2 μm or more, preferably 6 μm or more, in order to sufficiently cover the colors of the laser absorbing layer 4, the base material layer 2, and the shielding layer 1 described later by the laser marking layer 3. It is more preferably present, and further preferably 10 μm or more.

[1] Colored Pigments Examples of the colored pigments contained in the laser marking layer 3 include white pigments and organic pigments.

[1-1] White Pigment Examples of the white pigment include white pigments such as titanium oxide, zinc oxide (zinc white), basic lead sulfate, zinc sulfide, and antimony oxide. The white pigment may be barium sulfate, barium carbonate, precipitated calcium carbonate, diatomaceous earth, talc, clay, basic magnesium carbonate, alumina white, or the like. These white pigments can be contained in the laser marking layer 3 in an amount that does not excessively impair the absorption of laser light with respect to the resin components forming the continuous phase in the laser marking layer 3.

The content of the white pigment in the laser marking layer 3 is preferably 50 parts by mass or more and 300 parts by mass or less, with the resin component contained in the laser marking layer 3 as 100 parts by mass. When the content of the white pigment contained in the laser marking layer 3 is 50 parts by mass or more, it is possible to prevent the hue of the shielding layer 1 from being seen through the laser marking layer 3. Further, the resin component contained in the laser marking layer 3 is 100 parts by mass, and the resin component of the laser marking layer is thermally decomposed by irradiating the laser marking layer 3 with a laser beam having an appropriate output to be 300 parts by mass or less. The printed portion 10a can be preferably formed.

The median volume diameter of the white pigment is preferably 0.1 to 1 μm from the viewpoint of increasing the reflectance of light. The volume median diameter of the white pigment is a particle size (D50) corresponding to a cumulative 50% in the volume-based particle size distribution obtained by the laser diffraction / scattering method.

[1-2] Organic Pigment In addition, the laser marking layer 3 may contain an organic pigment within a range that does not impair the hue contrast with respect to the shielding layer 1. Examples of organic pigments include cyanine pigments with an elongated polymethine skeleton, nickel dithiolene pigments having a planar tetracoordinate structure, squalium pigments, naphthoquinone pigments, diimmonium pigments, azo organic pigments, and phthalocyanine. Condensed polycyclic organic pigments such as system pigments, naphthalocyanine pigments, and azulenocianine pigments are included. Examples of azulenosianin pigments include (10, 12, 22, 24, 34, 36, 46, 48-octoctyl) 2,3-azulenosianin zinc. Further, the organic pigment may be a commercially available product, and examples of the commercially available product include a near-infrared absorbing dye "FDN-010" manufactured by Yamada Chemicals, Inc. and a near-infrared absorbing dye manufactured by Yamamoto Chemicals, Inc. The dye "YKR-2200" is included. Further, the laser marking layer 3 may contain carbon black as an organic pigment as long as the hue contrast with the shielding layer 1 is not impaired on the surface 3a of the laminated body 100.

That is, the color exhibited by the material of the laser marking layer 3 may be appropriately determined according to the color exhibited by the shielding layer 1 within a range in which the printing is sufficiently clearly displayed.

The content of the organic pigment other than the white pigment contained in the laser marking layer 3 is not limited as long as the difference in L value with respect to the hue of the shielding layer 1 is 7 or more, preferably 10 or more, and the laser marking layer 3'described later is not limited. It can be used as the content of the organic pigment contained in.

[2] Resin component contained in the laser marking layer 3 The laser marking layer 3 contains an acrylic copolymer as a resin component.

The laser marking layer 3 may further contain materials other than the above resin components and pigments as long as the effects of the present embodiment are exhibited. For example, the resin other than the pigment in the laser marking layer 3 may be one kind or more, and examples thereof include a polyol, a urethane resin, a cellulose resin, and a cross-linking agent such as polyisocyanate.

<Laminated body 101 according to another embodiment>
The laminate according to one embodiment of the present invention is not limited to the laminate 100 according to the above embodiment. For example, as shown in FIG. 3, the laminate 101 according to the embodiment of the present invention has a laser marking layer (first layer) 3 and a laser marking layer (first layer) 3'from the surface 3a side. This is a laminate in which the laser absorbing layer (second layer) 4, the base material layer 2, and the shielding layer 1 are laminated in this order. That is, the laser marking layer 3'and the laser absorbing layer 4 are laminated between the laser marking layer 3 and the base material layer 2. In the laminated body 101, the film layer provided with the base material layer 2, the laser marking layers 3 and 3', and the laser absorbing layer 4 before the shielding layer 1 is formed is referred to as a laser marking film 11.

As shown in FIG. 4, the surface of the laminated body 101 is such that the laser marking layers 3 and 3'and the laser absorbing layer 4 are both etched by irradiating the laminated body 101 with laser light from the surface 3a side. The printing portion 11a is formed on the 3a side. In the laminated body 101, the members having the same functions as the members of the laminated body 100 are designated by the same reference numerals as those of the laminated body 100, and the description thereof will be omitted.

[Laser marking layer 3']
The laser marking layer 3'is a layer that serves as a base for the laser marking layer 3 in the laminated body 101 viewed from the surface 3a side, and is a layer provided between the laser marking layer 3 and the laser absorbing layer 4. The laser marking layer 3'contains both an organic pigment such as carbon black and a white pigment. The laser marking layer 3'is toned to an intermediate hue between the laser marking layer 3 which is a light and bright hue and the laser absorbing layer 4 which is a dark and dark hue. As a result, the hues of the laser absorbing layer 4 and the shielding layer 1 are transparent to the surface 3a side of the laminated body 101, and the hue of the laser marking layer 3 is prevented from changing.

The laser marking layer 3'is one aspect of the laser marking layer 3, and the content of the coloring pigment contained in the resin component is based on the content of these pigments in the laser marking layer 3. Further, since the laser marking layer 3'contains the same resin component as the laser marking layer 3, the description of the resin component will be omitted.

The laser marking layer 3'is one aspect of the laser marking layer 3, and the film thickness thereof is preferably 1 μm or more and 20 μm or less in total with the film thickness of the laser marking layer 3.

[Laser absorption layer 4]
The laser absorbing layer 4 is a layer that absorbs laser light like the laser marking layer 3, but may have the same hue as the hue of the shielding layer 1. In this respect, it differs from the laser marking layer 3. Further, the laser absorbing layer 4 is different from the shielding layer 1 in that it does not substantially contain the scaly filler. The term "substantially free of scaly filler" means that the laser absorbing layer 4 does not substantially contain the laser absorbing layer 4 to the extent that it does not function as the shielding layer 1. The difference in these points distinguishes the laser absorbing layer 4 from the laser marking layer 3 and the shielding layer 1. The laser absorbing layer 4 that absorbs the laser light is sometimes referred to as a second layer in order to distinguish it from the laser marking layer (first layer).

The laser absorbing layer 4 contains an organic pigment as a main pigment, and preferably contains carbon black as an organic pigment. Since the laser absorbing layer 4 contains an organic pigment, the hue is dark and has a dark hue, and since it does not substantially contain a scaly filler, the laser light shielding property is low. That is, the laser absorption layer is less likely to reflect the laser light, and therefore, the organic pigment contained in the laser absorption layer absorbs the laser light and easily generates heat. Therefore, the laser absorption layer 4 is easily thermally decomposed, and gas that may be generated by the decomposition of the resin component is easily generated. Therefore, when the laser absorbing layer 4 absorbs the laser light and decomposes, the laser marking layers 3 and 3'located on the laser absorbing layer 4 are etched together, and as a result, the surface 3a of the laminated body 101 is subjected to etching. Can perform precise printing. Further, in the laminate 101 according to the embodiment of the present invention, for example, as shown in FIG. 4, the shielding layer 1 is exposed even if the surface of the base material layer 2 is exposed after the laser absorbing layer 4 is successfully removed. The laser light can be shielded in. Further, the shielding layer 1 can shield a laser beam having a long wavelength while having a black hue. Therefore, it is possible to prevent the adherend attached to the adhesive surface 1a of the laminated body 101 from being damaged by the laser beam, and the hue of the shielding layer 1 can maintain a high hue contrast with the laser marking layer 3. Therefore, information such as a bar code or a two-dimensional code printed on the layered body 101 for laser marking can be suitably read by a code reader for reading the information.

The film thickness of the laser absorption layer 4 is preferably 0.5 μm or more, more preferably 1 μm or more, and more preferably 2 μm or more, from the viewpoint that the laser absorption layer 4 can be stably and easily produced. More preferred.

The organic pigment contained in the laser absorbing layer 4 is an organic pigment that can be contained in the above-mentioned laser marking layer 3, and more preferably carbon black.

<Laminated body 102 according to still another embodiment>
The laminate according to the embodiment of the present invention is not limited to the laminate 100 and the laminate 101. For example, as shown in FIG. 5, the laminate 102 according to still another embodiment of the present invention has a shielding layer 1'and an adhesive on the surface of the base material layer 2 facing the surface 3a of the laser marking film 11. The agent layers 5 are laminated in this order. In the laminated body 102, the pressure-sensitive adhesive layer 5 is attached to the adherend via the pressure-sensitive adhesive surface 5a. Even with this configuration, even if the laser light emitted from the surface 3a side passes through the base material layer 2 and irradiates the shielding layer 1', the laser light can be suitably shielded by the shielding layer 1'.

[Shielding layer 1']
The shielding layer 1'contains a scaly filler and carbon black, and may contain a resin component similar to the resin component of the laser marking layer 3 as a resin component. The shielding layer 1'can shield the laser beam like the shielding layer 1 by containing the scaly filler and carbon black, but the function as the adhesive layer is not always necessary.

Since the contents of the scaly filler and carbon black contained in the shielding layer 1'are the same as those of the shielding layer 1, the description thereof will be omitted.

[Adhesive layer 5]
The pressure-sensitive adhesive layer 5 may have adhesiveness to which the laminate 102 can be attached to an adherend (not shown), and the pressure-sensitive adhesive layer 5 does not substantially contain carbon black and scaly filler.

In the present specification, the composition for forming the pressure-sensitive adhesive layer substantially free of carbon black and scaly filler is simply referred to as "adhesive", whereby the shielding layer is described. It is distinguished from the "adhesive composition" which is an embodiment of the "coating composition" for forming 1 and 1'.

The pressure-sensitive adhesive layer 5 may be formed of, for example, a known pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive, a silicone rubber-based pressure-sensitive adhesive, and a synthetic rubber-based pressure-sensitive adhesive. The composition for forming the agent layer 5 is more preferably an acrylic pressure-sensitive adhesive.

The film thickness of the pressure-sensitive adhesive layer 5 is in the range of 1 μm or more and 200 μm or less, and more preferably in the range of 5 μm or more and 100 μm or less. When the film thickness of the shielding layer 1 is 5 μm or more, the pressure-sensitive adhesive layer 5 having the following suitable adhesiveness can be formed, and when the film thickness of the pressure-sensitive adhesive layer 5 is 100 μm or less, the laminated body 102 is covered. It can be attached by appropriately following the curved surface or unevenness of the body.

<Laminated body 103 according to still another embodiment>
The laminate according to the embodiment of the present invention is not limited to the laminate 100, the laminate 101, and the laminate 102. For example, as shown in FIG. 6, the laminated body 103 according to still another embodiment of the present invention is formed by laminating the shielding layer 1 ”, the laser marking layer 3, and the pressure-sensitive adhesive layer 5 in this order. The laser marking film 13 in the above includes a shielding layer 1 ”and a laser marking layer 3. In the laminated body 103, the pressure-sensitive adhesive layer 5 is formed on the shielding layer 1 ”side of the laser marking film 13.

[Shielding layer 1 "]
Since the contents of the scaly filler and the carbon black contained in the shielding layer 1 ”are the same as those of the shielding layer 1, the description thereof will be omitted.

<Other laminates>
The laminate according to the present invention is not limited to the laminates 100, 101, and 102. For example, in the laminate according to still another embodiment, the shielding layer and the laser marking layer are laminated in this order, the laser marking layer has the same configuration as the above-mentioned laser marking layer 3, and the shielding layer is described above. It has the same configuration as the shielding layer 1 or the shielding layer 1'. As a result, it is possible to obtain a laminate for laser marking having a shielding layer having a high shielding property against laser light.

<Manufacturing method of laminated body>
The method for producing a laminate according to an embodiment of the present invention can be produced by using a known method for producing a laminate for laser marking. For example, the laminate according to one embodiment includes a step of preparing a shielding layer and a step of forming a laser marking layer (first layer).

Further, the method for producing a laminate according to one embodiment may include a step for forming a laser absorption layer (second layer), or may include a step for forming an adhesive layer.

The step of applying the coating liquid composition or ink may be a step of applying the coating liquid composition or ink on the base material layer (base material film), and the method of applying the coating liquid composition or ink may be used. Is a known coating method. Examples of such coating methods include screen printing, gravure printing, bar coating, knife coating, roll coating, comma coating, blade coating, die coating, spray coating, electrostatic coating and dip coating. included.

The step of drying the coating liquid composition or ink to form the coating layer or ink layer may be, for example, a step of drying the coating liquid composition or ink by heating with a known heating device, and is known. Examples of the heating device include an infrared heater, a hot air heater, and a heating device such as an oven or a hot plate. In the step of forming the coating layer, the evaporation of the diluent contained in the coating liquid composition or the ink and the cross-linking reaction of the resin component contained in the coating liquid composition or the ink are promoted, and the coating layer or the coating layer or the ink is formed. An ink layer is formed.

In the step of curing the coating layer or the ink layer and forming the shielding layer, the laser marking layer or the laser absorbing layer, the coating layer, the laser marking layer or the laser absorbing layer is heated by the above-mentioned known heating device. It is preferable to complete the cross-linking reaction of the resin component contained in the coating layer or the ink layer to the extent that the function as a shielding layer, a laser marking layer, or a laser absorbing layer can be exhibited.

In addition, in the step of preparing the shielding layer, a thermoplastic resin for film molding is used as a resin component, and a scaly filler and carbon black are melt-kneaded with the resin component, and then, for example, extrusion molding, stretch molding, and pressing. It may be a step of molding into a film by a known molding method such as molding, blow molding, and inflation molding. Further, the step of preparing the shielding layer is not limited as long as a base film containing a scaly filler and carbon black can be obtained.

The method for producing a laminate is such that a plurality of ink layers are formed on a base material layer and a laminate having a plurality of laser marking layers (first layer) having different hues is provided within the range in which the effect of the present invention can be obtained. It may be formed. Further, as a result, a laminate in which the base material layer, the laser absorption layer (second layer) and the laser marking layer (first layer) are laminated in this order may be formed.

〔summary〕
The laminate according to the embodiment of the present invention is a laminate for laser marking, which includes a shielding layer having a shielding property against laser light and a laser marking layer, and the shielding layer is a resin component and carbon black. , And a scaly filler. As a result, the laminated body can clearly print on the surface of the laminated body by utilizing the shielding layer having a high shielding property while having a dark color.

In the laminate according to the embodiment of the present invention, it is more preferable that the scaly filler is titanium oxide-coated mica. As a result, the laminate can reduce the reflectance of red light, and it is possible to prevent reading defects from occurring when reading a one-dimensional code or a two-dimensional code.

In the laminate according to the embodiment of the present invention, the content of the scaly filler contained in the shielding layer is 4.5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the resin component. It is preferable to have. As a result, the laminated body can impart sufficient strength to the shielding layer while having a high shielding property.

Further, in the laminate according to the embodiment of the present invention, the content of carbon black contained in the shielding layer is 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the resin component. Is more preferable. As a result, a laminated body having high shielding property and clear printability can be obtained.

Further, in the laminate according to the embodiment of the present invention, the resin component contains an acrylic copolymer, and the acrylic copolymer has a butyl (meth) acrylate monomer ratio of% by weight or more and a carboxyl group. It is more preferable that the ratio of the acrylic monomer having the above is less than 10% by weight. As a result, adhesiveness can be imparted to the shielding layer.

Further, the laminate according to the embodiment of the present invention is an adhesive composition for attaching a laminate for laser marking to an adherend, and contains carbon black, a scaly filler, and a resin component. Is more preferable. As a result, it is possible to produce a laminated body which can perform clear printing on the surface and can be attached to an adherend by using a shielding layer having a high shielding property while having a dark color. Therefore, the pressure-sensitive adhesive composition for forming the shielding layer is within the scope of the present invention.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

An embodiment of the present invention will be described below.
[Preparation of materials]
[acrylic resin]
The acrylic resins used in the coating liquids of the inks A1, A2 and B, Examples 1 to 16 and Comparative Examples 1 to 3 are shown below.
Acrylic resin A: Nikalite H4007K4
Molecular weight Mw: 8000
Acrylic Adhesive 1: Nisetsu SY-2523
Molecular weight Mw: 600,000 Acrylic resin A and acrylic pressure-sensitive adhesive 1 are both products of Nippon Carbide Industries Co., Ltd., and "Niclite" and "Nisetsu" are both registered trademarks of the same company.

[Polyol]
The polyols used for the inks A1, A2 and B are shown below.
Polyol 1: Praxel L320AL
Polycaprolactone polyol
Hydroxy group value: 85 mgKOH / g, molecular weight: Mn2000
Polypoly 2: Praxel 305
Polycaprolactone polyol
Hydroxy group value: 305 mgKOH / g, molecular weight: Mn500
Both polyols 1 and 2 are products of Daicel Corporation, and "Plaxel" is a registered trademark of Daicel Corporation.

[Polyisocyanate]
The polyisocyanates used in the coating liquids of the inks A1, A2 and B, Examples 1 to 16 and Comparative Examples 1 to 3 are shown below.
Polyisocyanate 1: Takenate D-268
TDI isocyanurate, NCO% = 7.5%
Polyisocyanate 2: Takenate D-140N
IPDI isocyanurate, NCO% = 10.5%
Polyisocyanate 3: Takenate D-140N-60
IPDI isocyanurate, NCO% = 8.4%
Polyisocyanate 4: Coronate HK
Polyisocyanate containing isocyanurates of HMDI
NCO% = 20%
Polyisocyanate 5: Coronate L45E
TDI TMP adduct, NCO% = 7.9%
Polyisocyanates 1 to 3 are all products of Mitsui Chemicals, Inc., and "Takenate" is a registered trademark of the company. Polyisocyanates 4 and 5 are both products of Toray Industries, Inc., and "Coronate" is a registered trademark of Toray Industries, Inc.

[Pigment]
The pigments used in the coating liquids of the inks A1, A2 and B, Examples 1 to 16 and Comparative Examples 1 to 3 are shown below.
Black Color Base 1: NBK-968 Black (manufactured by Nikko Bics Co., Ltd.)
Carbon black content: 15.7% by mass
Black Color Base 2: NX-591 Black (manufactured by Nikko Bics Co., Ltd.)
Carbon black content: 15.7% by mass
White Color Base 1: NBK-967 White (manufactured by Nikko Bics Co., Ltd.)
Titanium oxide content: 58.5% by mass
Scale-like filler 1: Iriodin 103WNT (manufactured by Merck Co., Ltd.)
Titanium oxide coated mica: 100% by mass
Scale-like filler 2: Aluminum paste FD-508H (manufactured by Asahi Kasei Corporation)
Each pigment is obtained as a color base. Therefore, the total content of the vehicle and pigments such as carbon black, titanium oxide, and titanium oxide-coated mica was calculated as the solid content.

[Preparation Example 1]
Acrylic resin A, polyol 1, and black color base 1 were added to Polyflow No. 1 with the contents shown below. 85HF was mixed and then diluted with ethyl acetate to a solid content of 30% by weight. As a result, ink A1 for the laser absorption layer (second layer) was obtained.
Acrylic resin A: 50.0 parts by mass Polyol 1: 50.0 parts by mass Polyisocyanate 1: 12.0 parts by mass Black Color base 1: 22.4 parts by mass Polyflow No. 85HF: 2.8 parts by mass Polyflow No. 85HF (manufactured by Kyoeisha Chemical Co., Ltd.) is an acrylic leveling agent.

[Preparation Example 2]
Syricia 445 was mixed with ethyl acetate at the content shown below, and then acrylic resin A, polyol 1, polyisocyanate 1, polyisocyanate 2, black color base 1, and white color base 1 were mixed. After mixing, it was diluted with ethyl acetate so that the solid content was 30% by mass. As a result, ink A2 for the laser marking layer (first layer) was obtained. Syricia 445 (manufactured by Fuji Silysia Chemical Ltd.) is silica.
Syricia 445: 22.6 parts by mass Acrylic resin A: 70.0 parts by mass Polypoly 1: 30.0 parts by mass Polyisocyanate 1: 5.2 parts by mass Polyisocyanate 2: 7.7 parts by mass Black Color base 1: 5.2 Parts by mass White color base 1: 45.2 parts by mass

[Preparation Example 3]
Polyflow No. 1 in ethyl acetate at the content shown below. 85HF, BYK-370, and Syricia 445 were mixed, and then acrylic resin A, polyol 2, polyisocyanate 3, polyisocyanate 4, and white color base 1 were mixed. After mixing, the ink B was obtained by diluting with ethyl acetate so that the solid content was 55% by mass. BYK-370 (manufactured by Big Chemie Japan Co., Ltd.) is an OH group-containing silicone.
Polyflow No. 85HF: 3.8 parts by mass BYK-370: 4.6 parts by mass Syricia 445: 30.6 parts by mass,
Acrylic resin A: 80 parts by mass Polyol 2: 20 parts by mass Polyisocyanate 3: 36.0 parts by mass Polyisocyanate 4: 16.8 parts by mass White color base 1: 232.3 parts by mass

[Preparation Examples 4 to 23 (Examples 1 to 16 and Comparative Examples 1 to 3)]
The coating liquid compositions of Examples 1 to 16 and Comparative Examples 1 to 3 were prepared according to the following procedure with the compositions shown in Table 2. The amounts of the resin components of the acrylic pressure-sensitive adhesive 1, the polyisocyanate 5, the rosin ester, and the black color base 2 shown in Table 2 are based on the solid content described in the above-mentioned material preparation column, and are the resin components other than the pigment. The amount was calculated.

The rosin ester was dissolved in ethyl acetate, and the scaly filler 1, the acrylic pressure-sensitive adhesive 1, and the black color base 2 were mixed and stirred in this order, and then the polyisocyanate 5 was mixed and stirred. Then, the solid content was further adjusted to 30% by mass with ethyl acetate to obtain the coating liquid composition of Example 1. In the same manner, the coating liquid compositions of Examples 2 to 16 and Comparative Examples 1 to 3 were prepared. Pencel D-125 (Tg = 125 ° C., manufactured by Arakawa Chemical Industry Co., Ltd.) was used as the rosin ester, and scaly filler 2 was used in Example 16.

[Preparation of film layer]
Both sides of PET film S-50 (manufactured by Unitika Ltd.) were subjected to corona treatment. Ink A1 was applied to one surface of the PET film so that the film thickness after drying was 2 μm, and dried at 100 ° C. for 1 minute to form an ink layer A1. Next, the ink A2 was applied onto the ink layer A1 so that the film thickness after drying was 2 μm, and dried at 100 ° C. for 1 minute to form the ink layer A2. Subsequently, it was cured at 40 ° C. for 3 days. Ink B is applied onto the coating film A2 obtained by curing the ink layer A1 and the ink layer A2 so that the film thickness after drying is 15 μm, and dried at 150 ° C. for 1 minute. The ink layer B was formed. Then, the film was cured at 60 ° C. for 3 days to obtain a film layer in which the PET film, the coating film A1, the coating film A2, and the coating film B were laminated in this order.

[Manufacturing of laminate for laser marking]
The materials were mixed at the composition ratios shown in Table 1, and the coating solution of Example 1 in which the solid content concentration was adjusted to 30% by weight with ethyl acetate was applied to a release paper so as to have a film thickness of 20 μm after drying. It was processed and dried at 100 ° C. for 1 minute. After drying, a layer formed from the coating liquid was laminated on the surface of the film layer opposite to the surface on which each coating film was formed to obtain a laminate for laser marking. Then, the laser marking laminate was cured under the condition of 23 ° C./50% RH for 1 week.

[Evaluation of short wavelength laser printability]
The short wavelength laser printability was evaluated with a fiber laser marker LP-Z130 (manufactured by Panasonic Corporation). The short wavelength laser printability was evaluated under the basic conditions of an output of 75%, a pulse period of 50 Hz, a line width of 0.07 mm, and a scanning speed of 2000 mm / sec. As an evaluation by changing the output, the short wavelength laser printability was evaluated for each output corresponding to 135%, 120%, 100%, 80%, 60%, and 40% of the output under the basic conditions. As an evaluation by changing the scanning speed, evaluation was performed for each condition of 2000 mm / sec, 1600 mm / sec, 1200 mm / sec, 800 mm / sec, and 400 mm / sec. Further, as an evaluation by changing the pulse period, the pulse period was evaluated for each condition of 50 Hz and 30 Hz. The character "A" was printed by changing the printing frequency to once or twice. After that, the number of prints (those with a clear hue difference from the surface layer) and the number of penetrations were divided by the total number and evaluated. At this time, the number that penetrated is not included in the number that can be printed.
Print evaluation SS: The ratio of printing is 70% or more.
S: The printable ratio is 60% or more and less than 70%.
A: The ratio of printing was 50% or more and less than 60%.
B: The ratio of printing was 40% or more and less than 50%.
C: The ratio of printing was 30% or more and less than 40%.
D: The ratio of printing was less than 30%.
Penetration evaluation S: The percentage of penetration is less than 30%.
A: The percentage that penetrated is 30% or more and less than 40%.
B: The percentage that penetrated is 40% or more and less than 50%.
C: The percentage that penetrated is 50% or more and less than 60%.
D: The ratio of penetration is 60% or more.

[ _{Evaluation of CO 2} laser printability]
With CO ₂ laser marker ML-Z9510 (manufactured by Keyence Co., Ltd.), the output is 20%, 30%, 40%, 50%, 60%, 70%, 80%, and the scanning speed is 100 mm / sec, 200 mm / sec, A 1.5 mm square with a filled interior was printed under different conditions such as 300 mm / sec, 400 mm / sec, 500 mm / sec, 600 mm / sec, 700 mm / sec, 800 mm / sec, 900 mm / sec, and 1000 mm / sec. .. After that, the number of prints (those with a clear hue difference from the surface layer) and the number of penetrations were divided by the total number and evaluated. At this time, the number that penetrated is not included in the number that can be printed.
Print evaluation SS: The ratio of printing is 50% or more.
S: The printable ratio is 40% or more and less than 50%.
A: The ratio of printing was 30% or more and less than 40%.
B: The ratio of printing was 20% or more and less than 30%.
C: The ratio of printing was 10% or more and less than 20%.
D: The ratio of printing was less than 10%.
Penetration evaluation S: The percentage of penetration is less than 10%.
A: The percentage that penetrated is 10% or more and less than 15%.
B: The percentage that penetrated is 15% or more and less than 20%.
C: The percentage that penetrated is 20% or more and less than 40%.
D: The ratio of penetration is 40% or more.

[Evaluation of adhesive strength]
The laser marking laminates formed using the coating solutions of Examples 1 to 16 and Comparative Examples 1 to 3 were cured under the conditions of 23 ° C./50% RH for 1 week, respectively. After curing, a sample having a width of 10 mm and a length of 150 mm was cut out from each laser marking laminate. After that, the sample was attached to various adherends with a 2 kg roller at a rate of 20 mm / sec, and after 24 hours, the measurement length was 100 mm, and the adhesive force when pulled at a speed of 300 mm / min at an angle of 180 ° was measured. did.

〔Evaluation results〕
In the laminates of Examples 1 to 16, the carbon black content was changed from 0.8 parts by mass to 4.2 parts by mass with respect to 100 parts by mass of the resin component for evaluation. However, in the laminates of Examples 1 to 16 in which carbon black and titanium oxide-coated mica are used in combination, the printability and penetration resistance (shielding property) of each laser beam are expected to easily absorb these lights. It was not found to have a linear relationship with the carbon black content. More specifically, when titanium oxide-coated mica is used in combination, the relationship between the carbon black content and the penetration resistance and shielding property of each laser beam is that the carbon black content is 1.5 to 3.5 parts by mass. It was found that a favorable peak was shown between them. That is, it is presumed that if the content of carbon black becomes excessive, the shielding property by the titanium oxide coated mica is canceled, but by using more than 1.5 parts by mass of carbon black in combination, the titanium oxide coated mica is used. It was confirmed that the shielding effect was enhanced. It was confirmed that the laminated bodies of Comparative Examples 1 to 3 were particularly inferior in the light-shielding property (shielding property) of the laser light.

The present invention can be suitably used for displaying product information (manufacturing number, lot number, etc.) in industrial products, for example.

1 Shielding layer 1'Shielding layer 1 "Shielding layer 3 Laser marking layer (first layer)
3'Laser marking layer (first layer)
5 Adhesive layer 100 laminated body (laminated body for laser marking)
101 Laminate (Laminate for laser marking)
102 Laminate (Laminate for laser marking)
103 Laminated body (Laminated body for laser marking)
B laser light

Claims (6)

A laminate for laser marking
A shielding layer that has a shielding property against laser light,
Equipped with a laser marking layer,
The shielding layer is a laminate containing a resin component, carbon black, and a scaly filler. The laminate according to claim 1, wherein the scaly filler is a titanium oxide-coated mica. The laminate according to claim 1 or 2, wherein the content of the scaly filler contained in the shielding layer is 4.5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the resin component. .. The content of carbon black contained in the shielding layer is 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the resin component, according to any one of claims 1 to 3. Laminated body. The above resin component contains an acrylic copolymer and contains
Claims 1 to 4 of the acrylic copolymer, wherein the ratio of the butyl (meth) acrylate monomer is 80% by mass or more, and the ratio of the (meth) acrylic monomer having a carboxyl group is 10% by mass or less. The laminate according to any one of the above items. An adhesive composition for attaching a laminate for laser marking to an adherend.
A pressure-sensitive adhesive composition containing carbon black, a scaly filler, and a resin component.

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