JP2017111344A - Method of manufacturing brittle laser marker label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a brittle laser marker label for simply recording information (for example, company logo) on a black layer.SOLUTION: A brittle laser marker label 10 includes a black layer 14, a white layer 13, and an adhesive layer 12 in this sequence, and has, on a surface of the black layer, a black recess capable of being identified on the basis of the glossiness difference. In the method of manufacturing the brittle laser marker label, the black recess is formed by irradiating the black layer with laser so that the laser does not transmit through the black layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a brittle laser marker label.

  The laser marker label has a surface layer that absorbs laser light and can be removed by heat generation and destruction, and a lower layer that is disposed adjacent to the surface layer and has a brightness difference that is easily visible from the surface layer. Is a label that enables clear printing due to the color difference between the surface layer and the lower layer by cutting out characters and the like on the pattern. For example, the laser marker label has a black layer disposed on the surface layer and a white layer disposed on the lower layer of the black layer, and the black layer is shaved by laser light to expose the white layer that is the lower layer surface. Information is recorded by visually recognizing the white color inside.

  Laser marker labels are widely used for labels that display vehicle identification numbers (VIN) of automobiles, anti-theft labels, and the like. In the case of uses such as a label for displaying a vehicle identification number of an automobile or an anti-theft label, it is necessary to prevent the label from being replaced or falsified. For this reason, when trying to peel off the laser marker label from the adherend for the purpose of replacing or tampering with the label attached to the adherend, the label is destroyed and the label cannot be reused. It has been attempted to prevent the label from being replaced or tampered by imparting brittleness to the label.

  For example, Patent Document 1 discloses a laser marking film having a first label layer (for example, a black layer) as a surface layer and a second label layer (for example, a white layer) containing a brittleness imparting agent such as talc. Is disclosed. By adding this brittleness imparting agent, physically and mechanically brittle properties can be imparted to the second label layer, and the function to prevent peeling from the resulting label due to this brittleness Is going to be able to bring

  Incidentally, in a laser marker label having brittleness for the purpose of preventing falsification, a company logo or the like for preventing duplication may be recorded separately from recording information such as a vehicle identification number of an automobile. Information such as the vehicle identification number of an automobile needs to be clearly seen, for example, by making white visible in a black background as described above, while company logos are intended to prevent duplication, Rather, clear visibility is not required. As a method for differentiating the visibility of two pieces of information and recording the laser marker label, for example, Patent Document 2 discloses a technique for visually recognizing a logo or the like by providing a recess in the black layer of a laser marker label having a black layer and a white layer. It is disclosed. Specifically, a curable resin containing a black colorant such as carbon black is applied to the printed support carrier sheet, and after forming a white layer on the black layer, the support carrier sheet is removed, The indentation is formed on the black layer by transferring the print on the support carrier sheet to the black layer. Information formed by such depressions on the black layer is less visible than information performed by irradiating a laser that penetrates the black layer and reaches the white layer.

JP 2008-90063 A JP 2005-510765 A

  However, according to the method of Patent Document 2, it is necessary to prepare a support carrier sheet for each information (for example, a company logo) to be formed on the black layer, and when a plurality of information is continuously recorded on the black layer. It was very complicated.

  Accordingly, an object of the present invention is to provide a method for manufacturing a brittle laser marker label in which information (for example, a company logo) is simply recorded on a black layer.

  The present invention is a method for producing a brittle laser marker label comprising a black layer, a white layer, and an adhesive layer in this order, and having black recesses on the surface of the black layer that can be identified by the difference in glossiness. And forming a black recess by irradiating the laser so as not to penetrate the black layer.

  According to the method for manufacturing a brittle laser marker label of the present invention, a brittle laser marker label having information (for example, a company logo) on the black layer can be easily produced.

It is a section schematic diagram showing the manufacturing method of a first embodiment.

  1st embodiment of this invention is a manufacturing method of a brittle laser marker label which contains a black layer, a white layer, and an adhesive layer in this order, and has the black recessed part which can be identified by the difference in glossiness on the surface of a black layer. A method for producing a brittle laser marker label, comprising forming a black recess by irradiating a black layer with laser so as not to penetrate the black layer.

  When information is imparted to the black layer, the information has been imparted, for example, by forming a recess in the black layer by embossing as described in Patent Document 2 or printing by printing with a transparent ink. However, in the case of embossing, it is necessary to prepare a support carrier sheet for each information (for example, a company logo) to be formed on the black layer, which is very complicated. Further, in the case of printing, there has been a problem that the visibility of information printed due to wear decreases.

  On the other hand, the present embodiment is characterized in that the black recess is formed by irradiating the black layer with laser so as not to penetrate the black layer. A black recess having a lower gloss than that of the non-laser irradiated portion is formed by laser irradiation, and the black recess can be identified by a difference in gloss from the non-laser irradiated portion. The laser marker label prints information such as the product identification number by irradiating the laser under the condition that the laser reaches the white layer. Therefore, the laser irradiation condition of the laser irradiation device is changed by forming a black recess by laser irradiation. By doing so, two pieces of information can be formed in the black layer and the white layer.

  Furthermore, the black layer is provided for clearly viewing the information recorded in the laser on the white layer, and it is necessary that the laser penetrates and the label itself needs to be brittle. It is formed of a thin film. Even in such a black layer of a thin film layer, a recess can be formed by appropriately setting laser irradiation conditions.

  The information from the recesses with low glossiness in the black layer is less visible (not so noticeable) compared to the information from the recesses formed in the white layer. The information propagation can be differentiated by recording in the black layer information that is not so conspicuous as information.

  In the production method of the present embodiment, it is preferable that a dispersion obtained by dispersing a resin and a black colorant in a solvent is applied on a substrate (support film) and dried to obtain a black layer. In Cited Document 2, a paste in which an electron beam curable resin and carbon black are dispersed is applied to a support carrier sheet, and a black layer is formed by electron curing. However, in the case of the so-called solvent casting method, in which a resin-dissolved solution is applied to form a black layer, there is a problem that the solvent dissolves the support carrier sheet and the embossing cannot be performed sufficiently. The inventor found out. Therefore, in the case of embossing, there has been a limit to applying a method of forming a black layer by applying a coating solution containing a solvent. On the other hand, according to the manufacturing method of the present embodiment, since the black recess is formed by laser irradiation after the black layer is formed, the black layer can be formed even by a solvent casting method using a solvent.

  Hereinafter, this embodiment will be described.

  In this specification, “X to Y” indicating a range means “X or more and Y or less”. Unless otherwise specified, the operation and physical properties are measured under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50% RH. In the present specification, “(meth) acryl” means “acryl or methacryl”.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from actual ratios.

  FIG. 1 is a schematic cross-sectional explanatory view showing the manufacturing method of the first embodiment. In FIG. 1A, the laser marker label 10 is composed of a peeling member 11, an adhesive layer 12, a white layer 13 and a black layer 14.

  The laser marker label 10 is irradiated with laser light so as not to penetrate the black layer under a low output condition (FIG. 1B). By the laser light irradiation, a concave portion is formed in the black layer (FIG. 1C). Since the resin forming the black layer is dissolved and the bottom of the irradiated portion has irregularities, the bottom surface of the concave portion becomes a mat shape. The black recesses removed by the laser can be identified by the difference in glossiness between the glossy black layer surface and the matted recesses. That is, the black layer containing the resin can identify the black concave portion by the difference in glossiness by laser light irradiation. At this time, the irradiation condition of the laser beam is appropriately set under the condition that the concave portion is formed in the black layer 14 without penetrating the black layer 14.

  Next, the laser condition is set to medium output so that the laser beam penetrates the black layer 14 and reaches the white layer, and a concave portion is formed in the white layer (FIG. (D)). At this time, the irradiation condition of the laser beam is appropriately set so that the bottom of the concave portion is formed in the white layer 14 without penetrating the white layer 13.

  Further, the laser beam is set to a high output to cut the label and perform a punching process (FIG. 1E). By such a punching process, the laser marker label can be easily peeled off from the peeling member. At this time, the laser light irradiation conditions are set as appropriate under conditions that penetrate the black layer 14, the white layer 13, and the pressure-sensitive adhesive layer 12 and do not penetrate the peeling member 11.

  The order of laser processing is not particularly limited, and the order of removal of the black layer (FIG. 1C), removal of the white layer (FIG. 1D), and punching processing (FIG. 1E) is as follows. The order may be in order, and the removal order of the layers may be changed, or the removal may be performed collectively.

  Whether the laser marker label has brittleness can be defined by the method described in Examples.

  In the present embodiment, first, a laminate composed of the peeling member 11, the pressure-sensitive adhesive layer 12, the white layer 13 and the black layer 14 is formed (FIG. 1A). In addition, each layer is not necessarily limited to the form which adjoins, You may have a functional layer between each layer. For example, you may have an adhesive bond layer between a black layer and a white layer.

(1) Formation of black layer The formation method of a black layer is not specifically limited, It can form by the calendar method, the extrusion method, the solvent cast method, etc. Especially, it is preferable to form a black layer by the solvent cast method obtained by apply | coating and drying on a base material the dispersion liquid which disperse | distributed resin and a black colorant in the solvent. According to this method, a uniform coating film can be easily formed and formed on the support, so that the brittle black layer can be formed without breaking. The substrate (support film) is also referred to as a “process film” and is peeled off after the label is completed.

  At this time, since the glossiness of the black layer is improved and a difference in gloss between the laser non-irradiated part and the laser irradiated part is likely to occur, the support film is preferably smooth. Specifically, the black layer forming surface is a support film having an arithmetic average roughness (Ra) measured in accordance with a method defined in JIS B 0601: 2013 of 50 nm or less (lower limit: 0 nm). Is preferred. In addition, arithmetic average roughness (Ra) is specifically measured in an area of 1 μm × 1 μm for each of 10 arbitrary positions on the film surface, and the average value is calculated.

  Examples of the material of the support film include synthetic resin films such as polyethylene terephthalate, polyethylene naphthalate, polyimide, and polypropylene. The support film may be in a form having a release layer such as alkyd resin or silicone on these synthetic resin films. In this case, a black layer is formed on the release layer forming surface. The thickness of the support film is preferably 5 to 200 μm, more preferably 15 to 100 μm.

  Specifically, the solvent casting method prepares a dispersion in which a black colorant, a resin, and other optional components for forming a black layer are dispersed in a solvent (hereinafter also referred to as a black layer forming dispersion). After that, this dispersion is coated on the support film so as to have a predetermined dry thickness.

  Examples of the black colorant include carbon black, iron black, cobalt oxide pigment, aniline black, and perylene black. Among them, it is preferable to use carbon black as the black colorant used for the black layer because of its good absorption of laser light. The preferable average primary particle size of carbon black is in the range of 10 to 500 nm, more preferably in the range of 10 to 150 nm. Here, the average primary particle diameter of carbon black is an arithmetic average diameter obtained by observing 1000 carbon black particles with an electron microscope. Examples of carbon black include channel black, furnace black, acetylene black, and thermal black depending on the production method, and any of them can be used. The black colorants may be used alone or in combination of two or more.

  The content of the colorant in the black layer is preferably 1 to 50% by mass, and 5 to 20% by mass with respect to the solid content of the black layer forming dispersion from the viewpoint of colorability and mechanical strength. It is more preferable.

  In addition to the above black colorant, the dispersion may contain mica and aluminum powder as long as the colorability and weather resistance are not affected. When carbon black or the like is used, the black colorant can itself be a compound that converts laser light into heat. However, if the black colorant is not absorptive with respect to the laser beam, a compound for converting the laser beam into heat may be required. Examples of the compound for converting laser light into heat include cyanine-based and phthalocyanine-based infrared absorbers.

  As the resin, it is preferable to use at least one selected from the group consisting of a vinyl chloride resin, a urethane resin, and an acrylic resin from the viewpoint of laser processability.

  The resin preferably has an elongation at break of 10 to 180%, more preferably 20 to 150%. Here, when resin is comprised from multiple types, the elongation rate at the time of the whole resin points out. The elongation at break was determined by forming a film on the support film by a solvent casting method with a resin alone so as to have a dry film thickness of 15 μm, peeling the support film, and leaving at 22 to 25 ° C. for 1 hour or longer. After normal adjustment, the Instron-type tensile test was performed 6 times on a strip type test piece having a size of 20 × 100 mm under the conditions of a tensile speed of 5 mm / min, a chart speed of 100 mm / min, and a chuck interval of 50 mm. It is the value obtained by calculating the average value of the rates.

  The vinyl chloride resin includes polyvinyl chloride, vinyl chloride monomers, and copolymers of other monomers copolymerizable with vinyl chloride monomers (hereinafter also referred to as vinyl chloride copolymers). Examples of other monomers copolymerizable with vinyl chloride monomer include vinyl esters such as vinyl acetate, vinyl ethers such as ethylene vinyl ether, α-olefins such as ethylene, propylene, and 1-butene, and methyl acrylate. (Meth) acrylic acid esters such as ethyl acrylate, methyl methacrylate and butyl methacrylate, vinylidene chloride and the like. When using a vinyl chloride resin, a plasticizer is usually added for the purpose of imparting flexibility. Examples of the plasticizer to be added include, for example, dioctyl phthalate, dibutyl phthalate, diisononyl phthalate, octyl decyl phthalate, diisodecyl phthalate, di-2-ethylhexyl adipate, diisononyl adipate, Adipic acid plasticizers such as diisodecyl adipate, di-2-ethylhexyl azelate, di-2-ethylhexyl sebacate, tricresyl phosphate, trixyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, octyl phosphate Examples include diphenyl, chlorinated paraffin, chlorinated fatty acid ester, and epoxidized soybean oil. These plasticizers may be used alone or in combination of two or more. These polyvinyl chlorides or vinyl chloride copolymers can be produced by known production methods such as bulk polymerization, emulsion polymerization, and suspension polymerization. The average degree of polymerization of the vinyl chloride resin is usually 300 to 5,000. The average degree of polymerization is based on the average degree of polymerization calculation method described in JIS K 6720-2: 1999.

  As the urethane resin, a thermoplastic polyurethane resin is preferable. The thermoplastic polyurethane resin is obtained by reacting at least a polyisocyanate, a high molecular weight polyol, and a chain extender. Specifically, it is preferably obtained by reacting a chain extender with a terminal isocyanate urethane prepolymer obtained by reacting a polyisocyanate and a high molecular weight polyol.

  Examples of the polyisocyanate include aromatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate.

  Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4. '-Toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4', 4 "-triphenylmethane triisocyanate 1,4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, and the like.

  Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, Examples include 2,4,4-trimethylhexamethylene diisocyanate.

  Examples of the alicyclic polyisocyanate include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, and methyl-2. , 4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanatemethyl) cyclohexane, 1,4-bis (isocyanatemethyl) cyclohexane, etc. It is done.

  These polyisocyanates may be a trimethylolpropane adduct type modified product of the above polyisocyanate, a burette type modified product reacted with water, or an isocyanurate type modified product containing an isocyanurate ring.

  The high molecular weight polyol is an organic compound having two or more hydroxyl groups and a number average molecular weight of 400 or more, preferably 1000 to 3000. For example, polyether polyol, polyester polyol, polycarbonate polyol, acrylic polyol, epoxy polyol, natural oil Macropolyols such as polyols, silicone polyols, fluorine polyols, polyolefin polyols, polyurethane polyols and the like can be mentioned.

  The polyether polyol is, for example, a low molecular weight polyol and / or a low molecular weight polyamine as an initiator, and an alkylene oxide (for example, an alkylene oxide having 2 to 5 carbon atoms such as ethylene oxide, propylene oxide, butylene oxide) or cyclic. Ring-opening addition polymerization of ether (tetrahydrofuran, 3-methyltetrahydrofuran, oxetane compound) (homopolymerization or copolymerization (when alkylene oxide is used in combination with ethylene oxide and propylene oxide, block copolymerization and / or random copolymerization) )).

  Examples of the polyester polyol include a polyester polyol obtained by a condensation reaction or a transesterification reaction between a low molecular weight polyol and a polybasic acid, an alkyl ester thereof, an acid anhydride thereof, and an acid halide thereof. Examples of polyester polyols include polycaprolactone polyols and polyvalerolactone polyols obtained by ring-opening polymerization of lactones such as ε-caprolactone and γ-valerolactone using the above-described low molecular weight polyol as an initiator. And lactone polyester polyols obtained by copolymerizing these dihydric alcohols with polycaprolactone polyols, polyvalerolactone polyols, and the like.

  Examples of the polycarbonate polyol include a polycarbonate polyol obtained by addition polymerization of carbonates such as ethylene carbonate and dimethyl carbonate using a low molecular weight polyol as an initiator.

  Examples of the acrylic polyol include a copolymer obtained by copolymerizing a polymerizable monomer having one or more hydroxyl groups and another monomer copolymerizable therewith. Examples of the polymerizable monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, 2,2-dihydroxymethylbutyl (meth) acrylate, and polyhydroxy. Examples thereof include alkyl maleates and polyhydroxyalkyl fumarate. Moreover, as another monomer copolymerizable therewith, for example, (meth) acrylic acid, alkyl (meth) acrylate (C1-12), maleic acid, alkyl maleate, fumaric acid, fumaric acid Alkyl, itaconic acid, alkyl itaconate, styrene, α-methylstyrene, vinyl acetate, (meth) acrylonitrile, 3- (2-isocyanato-2-propyl) -α-methylstyrene, trimethylolpropane tri (meth) acrylate, Examples include pentaerythritol tetra (meth) acrylate.

  Examples of the epoxy polyol include an epoxy polyol obtained by reacting a low molecular weight polyol with a polyfunctional halohydrin such as epichlorohydrin or β-methylepichlorohydrin.

  Examples of the natural oil polyol include hydroxyl group-containing natural oils such as castor oil and coconut oil.

  As the silicone polyol, for example, in the copolymerization of the acrylic polyol described above, a vinyl group-containing silicone compound such as γ-methacryloxypropyltrimethoxysilane is used as another copolymerizable monomer. Examples include coalesced and terminal alcohol-modified polydimethylsiloxane.

  As the fluorine polyol, for example, in the copolymerization of the above-mentioned acrylic polyol, a copolymer containing a vinyl group-containing fluorine compound, for example, tetrafluoroethylene, chlorotrifluoroethylene, etc., as another copolymerizable monomer Etc.

  Examples of the polyolefin polyol include polybutadiene polyol and partially saponified ethylene-vinyl acetate copolymer.

  The polyurethane polyol reacts the above-mentioned macropolyol (for example, polyester polyol, polyether polyol, polycarbonate polyol, etc.) with the polyisocyanate at a ratio in which the equivalent ratio of hydroxyl group to isocyanate group (OH / NCO) exceeds 1. Thus, it can be obtained as a polyester polyurethane polyol, a polyether polyurethane polyol, a polycarbonate polyurethane polyol, or a polyester polyether polyurethane polyol.

  High molecular weight polyols may be used alone or in combination of two or more.

  The method for preparing the terminal isocyanate urethane prepolymer is not particularly limited. For example, a polyisocyanate, a high molecular weight polyol, a urethanization catalyst to be added if necessary, and a solvent to be used if necessary are used in a reactor. Examples include a method of charging and reacting.

  Examples of the chain extender include low molecular weight polyhydric alcohols having a number average molecular weight of less than 400, such as ethylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, sorbitol, Low molecular weight polyamine compounds such as ethylenediamine, 1,3-propanediamine, hexamethylenediamine, diaminocyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine, diethylenetriamine, triethylenetetramine, 2-hydroxyethylethylenediamine, 2-hydroxyethyl Propylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, Diamines having a hydroxyl group in the molecule such as 2-hydroxypropylethylenediamine; alkylene dihydrazines such as methylene dihydrazine, ethylene dihydrazine, propylene dihydrazine, adipic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid Examples thereof include saturated or unsaturated dihydrazines such as dihydrazide, phthalic acid dihydrazide, and itaconic acid dihydrazide; dimeramine amine obtained by converting the carboxyl group of dimer acid into an amino group. Moreover, these chain extenders can be used as chain length terminators by using them in excess relative to the isocyanate groups in the prepolymer.

  An acrylic resin refers to a resin produced by polymerization using a (meth) acrylic monomer as a main monomer component. Here, the main component means 50% by mass or more (upper limit 100% by mass) of the monomer component, preferably 80% by mass or more. Examples of (meth) acrylic monomers include acrylic acid esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, cyclohexyl acrylate, lauryl acrylate, stearyl acrylate; acrylic acid; methyl methacrylate, ethyl methacrylate, n -Methacrylic acid ester such as butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, stearyl methacrylate; methacrylic acid; This (meth) acryl monomer can also be used as a mixture of two or more.

  The acrylic resin may contain another monomer copolymerizable with the (meth) acrylic monomer as a monomer at the time of polymerization. For example, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, etc. Carboxyl group-containing monomers or anhydrides thereof; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; aromatic vinyl compounds such as styrene and substituted styrene; cyano group-containing monomers such as acrylonitrile; ethylene, propylene, Examples thereof include olefins such as butadiene; vinyl esters such as vinyl acetate; vinyl chloride; amide group-containing monomers such as acrylamide, methacrylamide, N-vinylpyrrolidone, and N, N-dimethylacrylamide.

  Preferable acrylic resins include, for example, (1) methyl methacrylate / methyl acrylate / butyl acrylate / styrene copolymer alone, (2) methyl methacrylate / methyl acrylate copolymer and methyl methacrylate / styrene / butyl acrylate copolymer. And a mixture thereof.

  Moreover, you may use a plasticizer for acrylic resin. As a plasticizer, what was mentioned in the column of the said vinyl chloride resin is mentioned.

  A cross-linking agent may be added to the black layer forming dispersion. As the crosslinking agent, a known crosslinking agent can be used, and examples thereof include, but are not limited to, an isocyanate crosslinking agent, an epoxy crosslinking agent, and a metal chelate crosslinking agent.

  Further, an additive may be added to the black layer forming dispersion in addition to the black colorant and the resin. Examples of the additive include an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a flame retardant, and a dispersant.

  The solvent used in the solvent casting method can be appropriately selected depending on the resin. Examples of the solvent include halogenated hydrocarbons such as methylene chloride, chloroform and tetrachloroethane, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate, ethyl lactate, butyl acetate and methyl 2-hydroxyisobutyrate, Aromatic hydrocarbons such as benzene, toluene, xylene, diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran, dioxane, and other ethers, propylene glycol monomethyl ether, ethyl cellosolve, ether alcohol such as butyl cellosolve, butyl cellosolve monoacetate, Ether esters such as propylene glycol monomethyl ether monoacetate, amides such as dimethylformamide and dimethylacetamide It can be used sulfoxides such as dimethyl sulfoxide. These solvents may be used alone or in combination of two or more.

  The amount of the solvent used in the solvent casting method is usually 100 to 400 parts by mass, preferably 150 to 350 parts by mass with respect to 100 parts by mass of the resin.

  The coating apparatus for casting the dispersion on the support film is not particularly limited, and examples thereof include coaters such as a comma coater, a lip coater, a die coater, a doctor blade coater, a bar coater, and a roll coater. It is done. Next, the solvent is removed by heating to form a film. The heating conditions are not particularly limited as long as the solvent is removed, but the heating and drying are usually performed at about 80 to 180 ° C. From the viewpoint of imparting mechanical strength and brittleness to the label, the coating thickness of the black layer forming dispersion is preferably 1 to 30 μm, and more preferably 5 to 20 μm.

  The formed black layer preferably has glossiness. Specifically, the glossiness of the black layer is defined by JIS Z 8741: 1997, and the glossiness of the surface (60 °) at an incident angle of 60 ° is 70. % Or more is preferable. In addition, the glossiness of a black layer is measured with respect to the black layer surface facing a white layer formation surface after peeling a support body film.

(2) Formation of white layer The formation of the white layer is not particularly limited, but a method of forming a white layer on the black layer formed above; after forming the white layer on a separate support film, And a method of laminating via a black layer formed by (1) and an adhesive layer. Preferably, after preparing a dispersion in which a white colorant, a filler and a resin for forming a white layer, and other optional components are dispersed in a solvent (hereinafter, a dispersion for forming a white layer), this is added to the black layer. It is preferable to use a solvent cast method in which a coating layer is applied on a (or support film) so as to have a predetermined dry thickness, and a solvent cast method in which a white layer-forming dispersion is applied on a black layer. Is more preferable. A specific solvent casting method is the same as the formation of the black layer.

  As the white colorant, inorganic pigments are preferable, and examples thereof include zinc white, zinc sulfide, titanium dioxide, calcium carbonate, clay, barium sulfate, alumina white, silica, and muscovite. Among these, from the viewpoint of imparting whiteness, the colorant is preferably rutile titanium dioxide (white). These white colorants may be used alone or in combination of two or more.

  Moreover, it is preferable that it is 5-55 mass% with respect to the dispersion liquid solid content for white layer formation, and, as for a white colorant, it is more preferable that it is 20-30 mass%.

  As the resin, it is preferable to use at least one selected from the group consisting of a vinyl chloride resin, a urethane resin, and an acrylic resin from the viewpoint of laser processability. Details of these resins are the same as those described for the black layer. The resin used for the black layer and the resin used for the white layer may be the same or different.

  The white layer forming dispersion preferably contains a filler in order to impart brittleness to the white layer. In addition, the filler here contains the coloring agent aiming at coloring. The filler may overlap with that described in the column of the colorant, but fused silica, aluminum hydroxide, barium sulfate, calcium carbonate, titanium dioxide, calcined clay, silica, diatomaceous earth, talc, alumina, Examples thereof include polyethylene terephthalate, polybutylene terephthalate, polycarbonate, nylon-6, nylon-6,6, cyclic olefin, a homopolymer of cyclic olefin, and a copolymer of cyclic olefin and ethylene. These fillers may be used alone or in combination of two or more. Among these, from the viewpoint of imparting brittleness, the filler is preferably at least one selected from fused silica, aluminum hydroxide, barium sulfate, calcium carbonate, and titanium dioxide.

  The average particle diameter of the filler is preferably 0.01 to 20 μm, more preferably 0.05 to 10 μm, and further preferably 0.1 to 4 μm. Here, the “average particle diameter” of the filler refers to a median diameter (median diameter) corresponding to a cumulative value of 50% in a volume-based particle distribution measured by a laser diffraction method.

  The content of the filler (including the white colorant) is preferably 5 to 55% by mass and more preferably 20 to 30% by mass with respect to the solid content of the white layer forming dispersion.

  A cross-linking agent may be added to the white layer forming dispersion. Examples of the crosslinking agent include the same ones as described in the column for the black layer forming dispersion.

  Furthermore, in addition to the white colorant and the resin, an additive may be added to the white layer forming dispersion. Examples of the additive include an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a flame retardant, and a dispersant.

  The thickness of the white layer is preferably 50 to 200 μm and more preferably 60 to 100 μm in consideration of the brittleness and mechanical strength of the white layer.

(3) Formation of pressure-sensitive adhesive layer The method of forming the pressure-sensitive adhesive layer is not particularly limited, and the pressure-sensitive adhesive is applied on the white layer; after the pressure-sensitive adhesive is applied to the release member and the pressure-sensitive adhesive layer is formed on the release member And a method of transferring the pressure-sensitive adhesive layer onto the white layer. The method for applying the pressure-sensitive adhesive composition is not particularly limited. For example, the adhesive composition is applied using a known coating apparatus such as a roll coater, knife coater, air knife coater, bar coater, blade coater, slot die coater, lip coater, or gravure coater. be able to. The coating thickness of the pressure-sensitive adhesive composition is usually 10 to 100 μm, preferably 20 to 60 μm after drying. A pressure-sensitive adhesive layer is formed by applying a drying treatment after applying the pressure-sensitive adhesive. It does not specifically limit as drying conditions in this case, Usually, it carries out on the conditions for 10 to 60 second at 60-150 degreeC.

  It does not specifically limit as an adhesive used for an adhesive layer, An acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a polyester adhesive, a styrene-diene block copolymer adhesive , Vinyl alkyl ether adhesives, polyamide adhesives, fluorine adhesives, and the like can be used. The pressure-sensitive adhesives may be used alone or in combination of two or more.

  As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive can be particularly preferably used from the viewpoint of reliability of adhesion. The acrylic polymer that constitutes the acrylic adhesive is a monomer (copolymerizable) that has (meth) acrylic acid alkyl ester as the main monomer component and can be copolymerized with (meth) acrylic acid alkyl ester as necessary. The monomer is preferably used. Examples of alkyl (meth) alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth) Isobutyl acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, (meth ) Dodecyl acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.

  Examples of acrylic copolymerizable monomers copolymerizable with alkyl (meth) acrylate include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, and (meth) acrylic. 2- (n-propoxy) ethyl acid, 2- (n-butoxy) ethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, (meth) acrylic acid 2 -(N-propoxy) propyl, (meth) acrylic acid 2- (n-butoxy) propyl and other (meth) acrylic acid alkoxyalkyl esters; (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, Carboxyl group-containing monomers such as isocrotonic acid or anhydrides thereof; sulfonic acid group-containing monomers such as sodium vinyl sulfonate Body; aromatic vinyl compounds such as styrene and substituted styrene; cyano group-containing monomers such as acrylonitrile; olefins such as ethylene, propylene and butadiene; vinyl esters such as vinyl acetate; vinyl chloride; acrylamide, methacrylamide, N -Amide group-containing monomers such as vinylpyrrolidone and N, N-dimethylacrylamide; Hydroxyl group-containing monomers such as hydroxyalkyl (meth) acrylate and glycerin dimethacrylate; Aminoethyl (meth) acrylate, (meth) Amino group-containing monomers such as acrylyl morpholine; Imido group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide; Epoxy group-containing monomers such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; 2 -Meta Isocyanate group-containing monomers such as liloyloxyethyl isocyanate; triethylene glycol diacrylate, diethylene glycol diacrylate, ethylene glycol diacrylate, tetraethylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, Examples thereof include polyfunctional copolymerizable monomers (polyfunctional monomer) such as trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, and divinylbenzene. These may be used alone or in combination of two or more.

  The weight average molecular weight of the acrylic polymer is preferably 400,000 to 2,000,000. The weight average molecular weight is a value in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

  The acrylic pressure-sensitive adhesive preferably contains a crosslinking agent in addition to the acrylic polymer. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, and a metal chelate crosslinking agent. The addition amount of the crosslinking agent is preferably 0.001 to 10 parts by mass and more preferably 0.005 to 5 parts by mass with respect to 100 parts by mass of the acrylic polymer.

  If necessary, a colorant, a filler, an antistatic agent, a tackifier, a wetting agent, a leveling agent, a thickener, an antifoaming agent, an antiseptic, and the like can be appropriately added to the pressure-sensitive adhesive layer.

  A peeling member is a member which has a function which protects an adhesive layer and prevents the fall of adhesiveness. And a peeling member peels from a coating-film protection sheet, when affixing on a coating film. For this reason, the laser marker label in the present invention includes those not having a peeling member.

  Although it does not specifically limit as a peeling member, Plastic films, such as polyester films, such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyolefin films, such as polypropylene and polyethylene; fine paper, glassine paper, kraft paper, Paper such as clay coated paper may be mentioned.

  The thickness of the peeling member is usually about 10 to 400 μm. Moreover, the layer which consists of release agents comprised from the silicone etc. for improving the peelability of an adhesive layer may be provided in the surface of a peeling member. When such a layer is provided, the thickness of the layer is usually about 0.01 to 5 μm.

(4) A step of forming a black recess by irradiating the black layer with laser so as not to penetrate the black layer. The laser is irradiated to the formed black layer. The bottom surface of the recess formed by melting the resin by laser irradiation becomes a mat shape. Due to the difference in glossiness between the glossy black layer surface and the matted concave portion, the portion of the black concave portion removed by the laser can be visually recognized. What is recorded by forming a concave portion in the black layer with a laser is not particularly limited, and may be any character, numeral, symbol, figure, or the like.

Examples of the laser that can irradiate the black layer include a CO ₂ laser, an Nd: YAG laser, an excimer laser, a semiconductor laser, a semiconductor excitation solid laser, an Ar laser, an N ₂ / Dye laser, and a HeCd laser. In general, it is preferable to use a CO ₂ laser, an Nd: YAG laser, or the like that is inexpensive and relatively easy to handle.

  The laser irradiation conditions (scanning speed, laser intensity, etc.) for forming the black layer recesses are appropriately determined under conditions that do not penetrate the black layer in consideration of the laser irradiation apparatus to be used and the resin type that forms the black layer. Can be set.

  Moreover, it is preferable that the depth from the surface in a black layer recessed part to a bottom part is 20 to 50% with respect to the thickness of a black layer.

(5) Step of forming white recording portion by irradiating laser on white layer Next, laser irradiation is performed under the condition of penetrating the black layer and reaching the white layer (and the white portion does not penetrate). To form a white recording portion in the white layer. What is recorded by forming a concave portion with a laser in the white layer is not particularly limited, and may be any character, number, symbol, figure, or the like.

  When the white layer is exposed by the laser irradiation, a recording portion that is a desired character (for example, a vehicle identification number) or the like is visually recognized by comparing the colors of the black layer and the white layer.

  As the laser irradiation conditions (scanning speed, laser intensity, etc.) for forming the white layer recording portion, the white layer penetrates the black layer in consideration of the laser irradiation apparatus to be used and the resin type that forms the black layer. Can be set as appropriate under conditions that do not pass through.

(6) Punching process Further, the punching process may be performed by laser irradiation up to the surface of the peeling member.

  The laser irradiation conditions (scanning speed, laser intensity, etc.) for the punching process can be appropriately set in consideration of the laser irradiation apparatus to be used, the type of resin forming each layer, and the like.

(Use)
Since the laser marker label of the present embodiment is broken when the label is peeled off from the adherend, it can be used as various tamper-proof labels. For example, it can be used as an anti-tampering label for display contents such as features of automobile identification numbers, automobile anti-theft labels, automobile parts, electrical / electronic parts, precision machine parts, etc. .

  The effects of the present invention will be described using the following examples and comparative examples. In the examples, “parts” or “%” may be used, but “parts by mass” or “% by mass” is indicated unless otherwise specified. Unless otherwise specified, each operation is performed at room temperature (25 ° C.).

Example 1
(1) Preparation of Resin Composition Z As resin composition Z, a methyl methacrylate / methyl acrylate copolymer [Mitsubishi Rayon Co., Ltd., “Acrypet (registered trademark) MD”, elongation at break 2.6%] 60 parts by mass, methyl methacrylate / styrene / butyl acrylate copolymer [Mitsubishi Rayon Co., Ltd., "Acrypet (registered trademark) RF065", elongation at break 165.0%] 40 parts by mass, carbon black [Mitsubishi Chemical Co., Ltd., trade name “RCF # 44”, average primary particle size 24 nm] 10 parts by mass, dimethylformamide 176 parts by mass and methyl ethyl ketone 68 parts by mass, sufficiently stirred and dispersed, dissolved, solid content concentration 31 masses % Dispersion was prepared.

(2) Preparation of Resin Composition W As the resin composition W, a methyl methacrylate / methyl acrylate copolymer [Mitsubishi Rayon Co., Ltd., “Acrypet (registered trademark) MD”, elongation at break 2.6%] 60 parts by mass, methyl methacrylate / styrene / butyl acrylate copolymer [Mitsubishi Rayon Co., Ltd., "Acrypet (registered trademark) RF065", elongation at break 165.0%] 40 parts by mass, rutile titanium dioxide [ Ishihara Sangyo Co., Ltd., trade name “Taipeku CR-57”, average particle size of 0.25 μm] is mixed with 30 parts by mass in solid content, 176 parts by mass of dimethylformamide and 68 parts by mass of methyl ethyl ketone, and sufficiently stirred and dispersed. Dissolved to prepare a dispersion having a solid content of 35% by mass.

(3) Production of laminated substrate sheet On the peelable process film [Lintec Co., Ltd., trade name “Enplus-03”; Ra 50 nm or less], the dispersion obtained in (1) above was applied, It was heated and dried at 150 ° C. to form a black layer having a thickness of 15 μm. Next, the dispersion obtained in (2) above is applied onto the black layer, heated and dried at 150 ° C. to form a white layer having a thickness of 75 μm, and then the process sheet is peeled off, A laminated substrate sheet having a thickness of 90 μm composed of a black layer and a white layer was produced. The glossiness of the black layer surface was 85%.

(4) Preparation of pressure-sensitive adhesive layer Using a reactor equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas introduction tube, 90 parts by mass of butyl acrylate monomer and 10 parts by mass of acrylic acid monomer were charged, and azobisisobuty An acrylic copolymer solution having a weight average molecular weight of 500,000 was obtained by adding 0.3 parts by mass of nitrile and polymerizing at 80 ° C. for 8 hours in a nitrogen gas atmosphere.

  An isocyanate-based crosslinking agent [Coronate L, manufactured by Tosoh Corporation] was added in an amount of 2 parts by mass based on 100 parts by mass of the solid content of the copolymer solution, and further diluted with toluene to prepare an adhesive solution.

  A pressure-sensitive adhesive having a thickness of 20 μm is obtained by applying the pressure-sensitive adhesive solution to a peeling-treated surface of a peeling member [manufactured by Lintec Corporation, “SP-8E”] using a knife coater and drying at 80 ° C. for 1 minute. A layer was formed.

  Subsequently, the said adhesive layer with a peeling member was bonded together on the white layer side of a lamination | stacking base material sheet, and the laser marker label was produced.

(5) Formation of black layer concave portion Using a CO ₂ laser marker LP-400 manufactured by Panasonic Corporation, the black layer was marked with a logo by laser irradiation so as not to penetrate the black layer. The depth from the black layer surface to the bottom of the concave portion was 5 μm.

(6) Formation of white layer recording portion Next, using a CO ₂ laser marker LP-400 manufactured by Panasonic Corporation, a laser was irradiated to mark characters by penetrating the black layer and reaching the white layer. The depth from the black layer surface to the bottom of the recording part was 20 μm.

  Both the logo formed on the black layer and the characters formed on the white layer were not faint and the printability was good.

<Brittleness>
A label was affixed to the adherend of the melamine coated plate and cured at room temperature (25 ° C.) for 24 hours. Thereafter, while warming with a dryer (temperature of 70 ° C. or higher), a razor blade was inserted into the interface between the pressure-sensitive adhesive layer and the adherend, and the label was peeled off from the adherend. At this time, the white layer that broke was considered brittle.

  The label printed on the black layer and the white layer was evaluated for the brittleness. As a result, the label was brittle.

10 Laser marker label,
11 Peeling member,
12 adhesive layer,
13 white layer,
14 Black layer.

Claims (3)

A black layer, a white layer and an adhesive layer are included in this order,
A method for producing a brittle laser marker label having a black recess that can be identified by a difference in glossiness on the surface of a black layer,
A method for producing a brittle laser marker label, comprising forming a black recess by irradiating a black layer with a laser so as not to penetrate the black layer.   The manufacturing method of the brittle laser marker label of Claim 1 which has apply | coating and drying on a base material the dispersion liquid which disperse | distributed resin and the black colorant in the solvent, and obtaining the said black layer.   The manufacturing method of the brittle laser marker label of Claim 1 or 2 with which the said black layer has at least 1 sort (s) selected from the group which consists of a vinyl chloride resin, a polyurethane resin, and an acrylic resin.