JP2021009191A - Retroreflective member with bar code - Google Patents

Abstract

To provide a retroreflective member with a bar code capable of reducing or preventing a decrease in readability of the bar code even when the bar code is applied to a patterned non-retroreflective part and a retroreflective member having a retroreflective part.SOLUTION: A retroreflective member 100 includes a retroreflective layer 110 comprising an overlay layer 118 including first and second principal surfaces 116, 117, and a plurality of retroreflective elements 112 arranged on the first principal surface 116, and the retroreflective member 100 can have a patterned non-retroreflective part and a retroreflective part viewed from the side of the second principal surface 117 of the overlay layer 118. A bar code 104 is provided on the second principal surface 117 of the overlay layer 118. A maximum value of a line width of the non-retroreflective part is approximately 50% or less of a minimum value of a line width of the bar code in the region of the bar code 104 and at a place where lines of the bar code 104 are not applied.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to retroreflective members.

Various articles having retroreflective performance have a function of converting the light incident on the article in the direction of returning it to the light emitting source. Due to this function, retroreflective articles are used, for example, in a wide range of applications where safety is required.

Patent Document 1 (Japanese Patent Laid-Open No. 2002-509277) describes a retroreflective article comprising a multilayer film covering a retroreflective layer on which a patterned engraved layer is printed, wherein the multilayer film is at least first. And an alternating laminate in which the second material is alternately laminated, the alternating laminate exhibits a relatively high reflectance with respect to light vertically incident in the first spectral region, within the second spectral region. A retroreflective article is described that is configured to exhibit relatively low reflectance for light incident perpendicular to.

Patent Document 2 (Japanese Patent No. 5986068) includes a retroreflective layer including a plurality of cube corner elements that collectively form a structured surface opposite to the main surface, and a first region and a second region. A first region and a first region having an opaque pressure sensitive adhesive layer, the second region comprising an opaque pressure sensitive adhesive layer in contact with a structured surface and a barrier layer in the first region, and having the barrier layer. Retrospective, where region 2 has sufficiently different properties to form a low index of refraction layer with a refractive index of less than 1.3 between the opaque pressure sensitive adhesive layer and the structured surface of the retroreflective layer. Sexually reflective articles are listed.

Special Table 2002-509277 Japanese Patent No. 5986068

Bar codes are attached to various articles. By reading this barcode, in addition to being able to directly convert it into information such as letters and numbers, it has become possible to guide users to websites, for example, so it has been attracting attention in a wide range of fields in recent years. In order to exert such a barcode function, it is necessary to have the barcode read by a reading device such as an optical camera.

However, depending on the structure of the retroreflective material, it may not be easy to identify and recognize the barcode with an optical camera due to the presence of a pattern other than the barcode on the surface.

The present disclosure reduces or prevents a decrease in readability of a bar code even when the bar code is applied to a retroreflective member having a patterned non-retroreflective part and a retroreflective part. Provide a retroreflective member capable of.

According to one embodiment of the present disclosure, it has a retroreflective layer comprising an overlay layer having first and second main surfaces and a plurality of retroreflective elements arranged on the first main surface. , A retroreflective member in which a patterned non-retroreflective portion and a retroreflective portion can be seen from the second main surface side of the overlay layer, and a bar code is provided on the second main surface of the overlay layer. , The maximum value of the line width of the non-retroreflective part in the area of the bar code and where the line of the bar code is not applied is about 50% or less of the minimum value of the line width of the bar code. A retroreflective member is provided.

According to another embodiment of the present disclosure, an article comprising the retroreflective member described above is provided.

According to the present disclosure, even when a bar code is applied to a retroreflective member having a patterned non-retroreflective part and a retroreflective part, a decrease in readability of the bar code is reduced or prevented. It is possible to provide a retroreflective member that can be used.

The above description should not be deemed to disclose all embodiments of the invention and all advantages relating to the invention.

It is sectional drawing of the retroreflective member with a bar code by one Embodiment of this disclosure. FIG. 5 is a cross-sectional view of a retroreflective member with a barcode according to another embodiment of the present disclosure. (A) to (d) are schematic views of a patterned non-retroreflective part and a retroreflective part according to one embodiment of the present disclosure. It is a table about the schematic diagram of the bar code which changed the ratio of W / C and the non-retrospective reflection part. It is a schematic diagram about the line width of a bar code. It is a schematic diagram of the bar code reading test by visible light. It is a bar code photograph of the retroreflective member of Example 1 in the bar code reading test by visible light. It is a bar code photograph of the retroreflective member of Comparative Example 1 in the bar code reading test by visible light. It is a bar code photograph of the retroreflective member of Example 2 in the bar code reading test by visible light. It is a photograph of the retroreflective member of Example 3 in the bar code reading test by visible light. It is a schematic diagram of the bar code reading test by infrared light. (A) is a barcode photograph of the retroreflective member of Example 3 in the barcode reading test using infrared light, and (b) is a barcode photograph of Comparative Example 2 in the barcode reading test using infrared light. It is a bar code photograph of a sex reflective member.

Hereinafter, the present invention will be described in more detail with reference to the drawings for the purpose of exemplifying typical embodiments of the present invention, but the present invention is not limited to these embodiments. Regarding reference numbers in drawings, elements with similar numbers in different drawings indicate that they are similar or corresponding elements.

In the present disclosure, "retroreflective" means a phenomenon in which light from a light source incident on a material (for example, visible light, infrared light, etc.) is reflected and reflected in the direction of the light source, or a characteristic of the material. In the present disclosure, "non-retroreflective" means a phenomenon in which no retroreflective occurs or retroreflective is reduced, or a property of a material.

In the present disclosure, for example, "above" in "providing a barcode on the second main surface of the overlay layer" means that the barcode is placed directly on the second main surface of the overlay layer, or , Means that the barcode is indirectly placed on the second main surface of the overlay layer via the other layer.

In the present disclosure, for example, "below" in "the cover layer is arranged below the barcode" means that the cover layer is arranged directly on the barcode below the barcode, or , Means that the cover layer is indirectly placed on the barcode via the other layers.

In the present disclosure, "(meth) acrylic" means acrylic or methacrylic, and "(meth) acrylate" means acrylate or methacrylate.

In the present disclosure, "transparent" or "transmitted" means the transmittance of light of a specific wavelength of interest, or infrared light including light of a specific wavelength range of interest (for example, visible light, near-infrared light, etc.). Etc.) means that the average transmittance is about 60% or more, preferably about 80% or more, and more preferably about 90% or more.

In the present disclosure, "opaque" or "impermeable" means the transmittance of light of a specific wavelength of interest, or infrared light including light of a specific wavelength range of interest (for example, visible light, near-infrared light, etc.). It means that the average transmittance (such as light) is about 40% or less, preferably about 20% or less, and more preferably about 10% or less.

The retroreflective member in one embodiment of the present disclosure will be illustrated with reference to the drawings.

FIG. 1 is a cross-sectional view of the retroreflective member 100 according to the embodiment of the present disclosure. The retroreflective member 100 includes a retroreflective layer 110, a first adhesive layer 130, and a low refractive index layer 138.

The retroreflective layer 110 includes an overlay layer 118 having a first main surface 116 and a second main surface 117 on the opposite side thereof, and a plurality of retroreflective elements 112 arranged on the first main surface 116. I have. The barcode 104 is arranged on the second main surface 117 of the overlay layer 118, which is on the observer 102 side. Here, the symbol "C" shown in FIG. 1 and FIG. 2 described later means the minimum value of the line width of the barcode.

The first adhesive layer 130 includes a first adhesive 132, a barrier layer 134, and a first base material 136. The barrier layer 134 is a layer for preventing the inflow of the first adhesive 132 between the structured surface 114 of the retroreflective element and the barrier layer 134, and the barrier layer 134 allows the low refractive index layer 138. Can be formed. Since the region in which the low refractive index layer 138 is formed exhibits retroreflective performance when light is incident from the observer 102 side, such a region corresponds to the retroreflective portion. On the other hand, in the region where the low refractive index layer is not formed due to the intrusion of the first adhesive 132, most of the light incident from the observer 102 side is transmitted without retroreflection, so that the region is , Corresponds to the non-retroreflective part. By the arrangement of this barrier layer, a patterned retroreflective part and a non-retroreflective part can be formed. In FIG. 1, the shape of the retroreflective element located in the non-retroreflective portion is retained, but such a shape may be crushed by a press or the like, or at a position corresponding to the non-retroreflective portion. The retroreflective element may not be formed. Here, the symbol "W" shown in FIG. 1 and FIG. 2 described later means the maximum value of the line width of the non-recursive reflection portion.

FIG. 2 is a cross-sectional view of another retroreflective member 200 according to an embodiment of the present disclosure. The retroreflective member 200 includes a retroreflective layer 210, a structured adhesive layer 230, and a low refractive index layer 238.

The retroreflective layer 210 is on the overlay layer 218 having the first main surface 216 and the second main surface 217 on the opposite side thereof, and the first main surface 216, similarly to the retroreflective layer 110 of FIG. It comprises a plurality of retroreflective elements 212 arranged in. The barcode 204 is arranged on the second main surface 217 of the overlay layer 218, which is on the observer 202 side.

The structured adhesive layer 230 includes a structured adhesive liner 240, a second adhesive layer 250, and a second base material 260. If the structured adhesive liner 240 has sufficient adhesive force to the second base material 260, the second adhesive layer 250 can be omitted. The structured adhesive liner 240 constituting the structured adhesive layer 230 has a raised region in which the adhesive is raised with respect to the surrounding region. This raised region joins the structured surface 214 of the retroreflective element 212 in the retroreflective layer 210 to define the low index layer 238. The region where the low refractive index layer 238 is formed corresponds to the retroreflective portion, and the region where the structured surface 214 of the retroreflective element 212 and the raised region of the structured adhesive liner 240 are joined is not. Corresponds to the retroreflective part. The raised region of the structured adhesive liner that joins the structured surface of the retroreflective element can form a patterned retroreflective and non-retroreflective portion. In FIG. 2, the shape of the retroreflective element located in the non-retroreflective portion is retained, but such a shape may be crushed by a press or the like, or at a position corresponding to the non-retroreflective portion. The retroreflective element may not be formed.

Hereinafter, for the purpose of exemplifying a typical embodiment of the present disclosure, details of each of the above components will be described with some reference numerals omitted.

The retroreflective layer includes an overlay layer and a plurality of retroreflective elements. The retroreflective element may be arranged directly on the overlay layer, indirectly via a bonding layer (primer layer) or the like, or the overlay layer may be shaped or printed in 3D. It may be integrally formed by using.

The material constituting the overlay layer is not particularly limited as long as it has the ability to transmit light (for example, visible light or infrared light) and can support or form a retroreflective element. For example, polycarbonate, poly (meth) acrylate (for example, polymethylmethacrylate), polyolefin (for example, polyolefin containing at least 50% by mass of alkylene having 2 to 8 carbon atoms. Specifically, polyethylene, polypropylene, etc.), polyester. (For example, polyethylene terephthalate, polyethylene naphthalate), polyamide, polyimide, phenol resin, cellulose diacetate, cellulose triacetate, polystyrene, styrene-acrylonitrile copolymer, cyclic olefin copolymer, epoxy resin can be mentioned. Alternatively, (1) fluorinated polymers such as polychlorotrifluoroethylene, polytetrafluoroethylene-co-hexafluoropyropyrene, polytetrafluoroethylene-co-perfluoroalkyl vinyl ether, polyvinylidene fluoride-co-hexafluoropropylene; (2) Polyethylene-co-methacrylic acid having sodium or zinc ions, for example, E.I. I. Inomeric ethylene polymers such as SURLYN-8920 brand and SURLYN-9910 brand available from duPont Nemours (Wilmington, Del); (3) Low density polyethylene; Linear low density polyethylene; and Ultra low density polyethylene; Plasticized poly Plasticized vinyl halide polymers such as vinyl chloride; (4) Acid-functional polymers such as polyethylene-co-acrylic acid, polyethylene-co-methacrylic acid, polyethylene-co-maleic acid, and polyethylene-cohumalic acid. Polyethylene copolymers containing: Acrylic functional polymers such as those with alkyl groups of methyl, ethyl, propyl, etc., or CH ₃ (CH ₂ ) _n − with n of 0-12, and polyethylene-co-vinyl acetate. ; And (5) aliphatic polyurethane; and the like can also be used. Alternatively, an inorganic material such as glass can also be used. These materials can be used alone or in combination of two or more. The overlay layer may contain any additives such as pigments, dyes, UV absorbers, antioxidants, light stabilizers, heat stabilizers, antistatic agents, and flame retardants, as long as they do not affect the effects of the present invention. It may contain more than a seed.

The overlay layer may be a single layer, or may have a laminated structure of two or more layers. The shape and thickness of the overlay layer are not particularly limited, and can be appropriately adjusted according to the intended use of the retroreflective member. Examples of the shape of the overlay layer include a film shape, a sheet shape, a plate shape, a curved surface shape, and a three-dimensional shape.

The retroreflective element is not particularly limited as long as it exhibits retroreflective performance, and a known retroreflective element can be used. For example, retroreflective elements such as light-transmitting beads and cube corners can be mentioned.

In some embodiments, the retroreflective element is preferably a cube corner element from the viewpoint of efficiency of retroreflective.

For example, the cube corner element may be a complete cube (sometimes referred to as a full cube or geometry cube), a truncated cube, a cube corner type triangular pyramid, a cube corner type cavity, and the like. For example, a cube corner element includes a three-sided structure with three sides that are substantially orthogonal to each other. When used, the retroreflective member is typically placed with the bar code plane facing the intended observer and light source. Light incident from the barcode surface side is incident on the retroreflective member and is reflected by each of the three sides of the cube corner element so as to be emitted from the barcode surface side in a direction substantially toward the light source. In some embodiments, the cube corner elements are tilted relative to each other to improve retroreflective properties over a wider range of incident ray angles. Illustrative embodiments of the retroreflective layer based on cube corners are U.S. Pat. Nos. 5,138,488 (Sczzech), 5,387,458 (Pavelka), 5,450,235 (Pavelka). Smith), No. 5,605,761 (Burns), No. 5,614,286 (Bacon), No. 5,691,846 (Benson, Jr.), and No. 7,422,334. It is disclosed in the issue (Smith).

The material of the retroreflective element is not particularly limited, and the same material as the overlay layer described above can be used. For example, polycarbonate, polymethylmethacrylate, polyethylene terephthalate, aliphatic polyurethane, ethylene copolymer, and ionomers thereof can be mentioned. The retroreflective element may contain one or more arbitrary additives such as an ultraviolet absorber, an antioxidant, a light stabilizer, and a heat stabilizer as long as the effect of the present invention is not affected.

The cube corner elements contained in the retroreflective layer can be formed by casting directly onto a resin film, for example, as described in US Pat. No. 5,691,846 (Benson, Jr.). When the retroreflective element is formed by ionizing radiation curing (for example, ultraviolet curing, electron beam curing), suitable resins include, for example, polyfunctional (meth) acrylate, epoxy (meth) acrylate, (meth) acrylicized urethane and the like. Examples thereof include a cured product of an ionizing radiation curable composition.

Among the above resins, for example, it is advantageous in one or more of thermal stability, environmental stability, transparency, excellent peelability from a tool or a mold, and adhesion to other layers, and is transparent. Hardened products of polycarbonate and epoxy (meth) acrylate are particularly advantageous in terms of properties, thermal stability and the like.

The thickness of the retroreflective layer can vary, for example, it can be about 40 micrometers or more, about 50 micrometers or more, or about 55 micrometers or more, about 150 micrometers or less, about 100 micrometers. It can be less than or equal to, or less than about 60 micrometers. The thickness of the retroreflective layer refers to the distance between the bar coded main surface of the retroreflective layer (the second main surface of the overlay layer) and the highest top of the structured surface.

The height of the retroreflective element can vary, for example, the height of the cube corner element can be about 50 micrometers or more, about 70 micrometers or more, or about 80 micrometers or more, about 150. It can be micrometer or less, about 120 micrometers or less, or about 100 micrometers or less. The height of the cube corner element is the distance between the bottom surface of the cube corner element (the first main surface of the overlay layer) and the highest top of the structured surface.

The thickness of the retroreflective layer and the height of the retroreflective element are measured in the thickness direction cross section of such a layer or element using a scanning electron microscope. Then, the average value of the thickness or height of any at least 5 points in these layers or elements can be defined as the thickness of the retroreflective layer or the height of the retroreflective element.

In some embodiments, the retroreflective member of the present disclosure may include a first adhesive layer. The first adhesive layer may include a first adhesive, a barrier layer, and optionally a first substrate, as illustrated in FIG.

The barrier layer shall have sufficient structural integrity to prevent the first adhesive from flowing into the low index layer formed between the structured surface of the retroreflective element and the barrier layer. Can be done. The barrier layer may be in direct contact with the tip of the retroreflective element, may be separated from the tip of the retroreflective element, or may be slightly pushed into the tip of the retroreflective element.

The barrier layer provides a physical barrier between the first adhesive and the retroreflective element, allowing the formation of a low index of refraction layer. The presence of the barrier layer allows retroreflection of light rays incident on a portion of the structured surface of the retroreflecting element adjacent to the low index layer and / or the barrier layer. In the region where the barrier layer is not formed, the first adhesive penetrates and adheres to the retroreflective element, which efficiently seals the retroreflective region and is optically active to exhibit retroreflective. Region or cell can be formed. The first adhesive can hold the retroreflective layer and the retroreflective member including the first adhesive layer together as a whole, eliminating the need for a separate encapsulation film and encapsulation process. can do. Since the periphery of the retroreflective region is sealed by the first adhesive, deterioration of the retroreflective characteristics due to dust or the like can be prevented or reduced.

Light rays incident from the barcode side with respect to the retroreflective element adjacent to the low refractive index layer can be retroreflected. In the present disclosure, for example, the region of the retroreflective member including the low refractive index layer is an optically active region capable of retroreflective and may be referred to as a “retroreflective portion”. In contrast, for example, the region of the retroreflective member that does not include the low index of refraction layer is an optically inactive region because it does not substantially retroreflect incident light rays, and is a "non-retroreflective part". It may be called.

As the material of the barrier layer, any material that can prevent the first adhesive from coming into contact with the retroreflective element or entering the low refractive index layer can be used. Typical materials used in the barrier layer include, for example, resins (eg, UV curable polymers), films, inks, dyes, pigments, inorganic materials, particles, beads and the like. These materials can be used alone or in combination of two or more.

The dimensions and spacing of the barrier layers may vary. In some embodiments, the barrier layer may form patterns such as grids, stripes, dots, letters, etc. on the retroreflective member.

The thickness of the barrier layer may vary, for example, it can be about 2 micrometers or more or about 3 micrometers or more, such as about 10 micrometers or less, about 8 micrometers or less, or about 4 micrometers or less. can do. The thickness of the barrier layer can also be measured using a scanning electron microscope as described above, and the average value of the thicknesses of at least five points in the barrier layer can be defined as the thickness of the barrier layer. it can.

The low refractive index layer of the present disclosure, if present, may be a layer having a lower refractive index than the adjacent retroreflective element, and the material to be composed is not particularly limited. The low refractive index layer is, for example, a material having a refractive index of about 1.30 or less, about 1.25 or less, about 1.20 or less, about 1.15 or less, about 1.10 or less, or about 1.05 or less. Can be included. For example, as a low refractive index material, air and, for example, US Patent Application No. Examples include low refractive index materials as described in 61 / 324,249 (all of which are incorporated herein by reference).

The first adhesive that can be used in the first adhesive layer is not particularly limited, and is, for example, a (meth) acrylic pressure-sensitive adhesive (for example, a crosslinked and plasticized (meth) acrylic pressure-sensitive adhesive). Adhesives) or hot melt pressure sensitive adhesives. Based on natural rubber, synthetic rubber, silicone or other polymers, such as tackifiers, antioxidants, UV absorbers, plasticizers, light stabilizers, heat stabilizers, antistatics, flame retardants, etc. as needed. Other pressure sensitive adhesives, including additives, can also be used. As used herein, the term "pressure sensitive adhesive" refers to an adhesive that is permanently adhesive at room temperature, adheres to various surfaces with light pressure, and does not exhibit a phase change (from liquid to solid). The first adhesive may be thermally crosslinked by a crosslinking agent or crosslinked by radiation (for example, an electron beam or ultraviolet rays).

The first base material in the first adhesive layer is not particularly limited, and for example, a resin material, an inorganic material such as glass, paper, or the like can be used. As the resin material, for example, a polyester resin such as polyethylene terephthalate, a polyolefin resin such as polyethylene, or the like can be used. The surface of the first base material may be peeled off with a silicone resin or the like and used as a peeling liner. The first substrate may contain one or more arbitrary additives such as pigments, dyes, ultraviolet absorbers, antioxidants, light stabilizers, heat stabilizers, antistatic agents, and flame retardants. ..

The thickness of the first adhesive layer may vary, for example, it can be about 30 micrometers or more, about 40 micrometers or more, or about 50 micrometers or more, about 150 micrometers or less, about 90. It can be micrometer or less, or about 60 micrometers or less. Here, the thickness of the first adhesive layer means that, when the first base material can be peeled off, the first adhesive above the top of the retroreflective element is the first base material. The distance to the surface applied to, and if the first substrate does not peel off, the surface above which the adhesive of the first substrate is applied from the top of the retroreflective element. The distance to the opposite surface of. The thickness of the first adhesive layer can also be measured using a scanning electron microscope as described above, and the average value of the thicknesses of any at least five points in the first adhesive layer can be measured. It can be defined as the thickness of the adhesive layer of 1.

In another aspect, the present disclosure relates to a method of manufacturing a retroreflective member having a retroreflective layer and a barrier layer and a first adhesive layer containing a first adhesive. The first adhesive layer comprises at least one barrier layer and a first adhesive. In this manufacturing method, a step of arranging a barrier layer on a first adhesive to form a first adhesive layer, and then a step of laminating the obtained first adhesive layer on a retroreflective layer. And include. The first adhesive layer can be formed by various methods including, but not limited to, the following typical methods. In one typical embodiment, the material forming the barrier layer is printed on the first adhesive. The printing method may be a non-contact method, for example, printing using an inkjet printer, or a contact printing method, for example, flexographic printing. In another typical embodiment, the material forming the barrier layer is printed on a flat peel surface, for example using an inkjet or screen printing method, and then transferred from the flat peel surface onto the first adhesive. Will be done. In another typical embodiment, the material forming the barrier layer is flood coated onto a liner having a microstructured surface, on which a first adhesive is laminated to microstructure the barrier layer. Transferred from the surfaced liner to the first adhesive.

In some embodiments, the retroreflective member of the present disclosure may comprise a structured adhesive layer. The structured adhesive layer can include a structured adhesive liner and any second adhesive layer and second substrate, as illustrated in FIG.

The material of the structured adhesive liner is not particularly limited, and for example, the same material as the above-mentioned first adhesive can be used. The structured adhesive liner includes a raised region that joins the structured surface of the retroreflective element, as shown in FIG. A low refractive index layer can be formed by applying a structured adhesive liner having such a raised region to the structured surface of the retroreflective element and sealing it. Light rays incident from the barcode side with respect to the retroreflective element adjacent to the low refractive index layer are retroreflective. In contrast, the region of the retroreflective member that does not include the low index of refraction layer is an optically inert region because it does not substantially retroreflect incident light rays. The retroreflective region sealed with the structured adhesive liner can prevent or reduce the deterioration of the retroreflective property due to dust and the like.

The structured adhesive liner can be formed by various methods including, but not limited to, the following typical methods. In one typical method, the structured adhesive liner optionally starts with a flat film of adhesive on the carrier web (second substrate). A carrier web with the adhesive is sandwiched between a flat roll and a roll with the desired relief pattern (raised pattern) and the relief pattern is transferred to the adhesive by applying temperature and pressure.

A second typical method can be made by preparing a castable or extrudable adhesive and extruding such an adhesive onto a roll having a desired relief pattern (raised pattern). When the adhesive is removed from the roll, the relief pattern associated with the roll is retained by the adhesive.

A third typical method prepares a flat second substrate of a thermoplastic film (such as a polyethylene film). The film is sandwiched between a flat roll and a roll with the required relief pattern and the raised relief pattern is transferred to the thermoplastic film by applying temperature and pressure. The adhesive can then be coated on the relief-patterned thermoplastic film using, for example, kiss coating or other suitable method to form a structured adhesive liner.

A fourth typical method prepares, for example, a film in which a non-adhesive raised region is formed. An adhesive can be applied to the surface of the raised portion to be joined to at least the retroreflective element of such film to form a structured adhesive liner.

The retroreflective member can be formed by applying the structured adhesive layer containing the obtained structured adhesive liner to the retroreflective element of the retroreflective layer. For example, they can be placed between two flat nip rolls and temperature and pressure can be applied as needed to form a retroreflective member. The surface of the second base material used in the production of the structured adhesive liner can be peeled off with a silicone resin or the like and used as a peeling liner. In this case, for example, a component in which the release liner is removed from the retroreflective member and the second adhesive is applied to another non-peelable second base material is structured via the second adhesive. It may be applied to an adhesive liner to form a retroreflective member having a structure as shown in FIG.

The material of the second base material is not particularly limited, and for example, the same material as the material of the first base material described above can be used.

The material of the second adhesive layer is not particularly limited, and for example, the same material as the above-mentioned first adhesive can be used. Alternatively, a thermoplastic resin polymer, a thermoactive adhesive, eg, an acid / acrylate or anhydride / acrylate-modified ethylene vinyl acetate copolymer (EVA), as described in US Pat. No. 7,611,251. , For example, Vinyl 310 and the like can be used.

The thickness of the structured adhesive layer can vary, for example, it can be about 30 micrometers or more, about 40 micrometers or more, or about 50 micrometers or more, about 150 micrometers or less, about 90 micrometers. It can be less than a meter, or less than about 60 micrometers. Here, the thickness of the structured adhesive layer is the surface of the structured adhesive liner above the top of the retroreflective element on the opposite side of the raised region, when the second substrate is removable. If the second substrate does not peel off, a structured adhesive liner or second adhesive layer of the second substrate above it is applied from the top of the retroreflective element. The distance to the surface on the opposite side of the surface. The thickness of the structured adhesive layer can also be measured using a scanning electron microscope as described above, and the average value of the thickness of any at least 5 points in the structured adhesive layer can be measured by structured adhesion. It can be defined as the thickness of the agent layer.

The retroreflective member of the present disclosure includes a patterned non-retroreflective portion (a portion without a hatching pattern) and a pattern as shown in FIG. 3 when viewed from the second main surface side of the overlay layer. The retroreflective part (the part where the dot-shaped hatching pattern is formed) can be visually recognized. These patterns can form various patterns depending on the arrangement state of the raised region of the barrier layer or the structured adhesive liner described above. The pattern may be, for example, a regular or irregular continuous or discontinuous pattern in the mechanical direction, the lateral direction (width direction), or both. The pattern of the retroreflective part may be, for example, an S-shaped pattern, a striped shape, a rectangular shape, a honeycomb shape, a scale shape, or a dot shape, or a written, language, alphanumeric character, symbol, image, logo. It may be.

As shown in FIGS. 1 and 2, the pattern of the non-retroreflective part corresponds to the place where the barrier layer is not formed or the raised region of the structured adhesive liner is formed, and the retroreflective part It is formed in a negative-positive relationship with respect to the pattern of. In the present disclosure, the "line width of the pattern of the non-retroreflective part" means, for example, the distance between the two retroreflective parts in the cases (a) and (b) of FIG. , In the case of (c) of FIG. 3, a common tangent line tangent outside the tangent circle of two adjacent retroreflective parts and two other adjacent retroreflective parts adjacent to the tangent line. In the case of (d) in FIG. 3, the distance between the two adjacent retroreflective parts and the opposite sides is intended, and the distance between the two adjacent retroreflective parts is intended. Intended. The maximum value of such a line width can be defined as the maximum value (W) of the line width of the pattern of the non-retroreflective part. For example, in the case of FIG. 3 (c), (g) and (h) exist as the line widths of the pattern of the non-retroreflective part, but the line (g) is the maximum value (W) of the line width. The width value is selected.

The size of the line width of the pattern of the non-retroreflective part is not particularly limited, and the required performance according to the intended use (for example, the adhesive strength between the retroreflective layer and the adhesive layer, durability, etc.) is taken into consideration. However, it can be adjusted as appropriate. For example, the maximum value of such a line width can be about 0.1 mm or more, about 0.2 mm or more, about 0.3 mm or more, about 0.5 mm or more, or about 0.7 mm or more, and about 25 mm or less. , About 20 mm or less, about 15 mm or less, about 10 mm or less, about 7 mm or less, about 5 mm or less, about 4 mm or less, about 3 mm or less, about 2 mm or less, or about 1 mm or less. The line width of the pattern of the non-retroreflective part can be measured using an optical microscope, and the average value of the line widths of any at least 5 points in the pattern of the non-retroreflective part can be measured by the non-retroreflective part. It can be defined as the line width of the pattern.

The retroreflective member of the present disclosure is provided with a barcode on the second main surface of the overlay layer on the observer side, and is within this barcode region, and the line of the barcode (light failure). The maximum value of the line width of the non-retroreflective portion at the place where the transmissive line) is not applied is configured to be about 50% or less of the minimum value of the line width of the barcode.

When the maximum value of the line width of the non-retroreflective part and the minimum value of the line width of the barcode are configured in such a ratio, it is possible to reduce or prevent a defect in reading performance by the barcode reader. it can. Since the non-retroreflective part is a region where the retroreflective performance is lower than that of the retroreflective part or does not exhibit the retroreflective performance, the non-retroreflective part is like a shadow, gray or black. It is considered that the color is recognized by the camera mounted on the reading device. As a result, the reading device tends to mistakenly recognize the non-retroreflective part as a part of the bar code. Therefore, the bar code applied to the retroreflective member having the non-retroreflective part has retroreflective ability. It is considered that the reading device is more difficult to read than the bar code applied to the non-reflexive paper or the retroreflective member having no non-retroreflective part as described in Patent Document 1.

From the viewpoint of barcode readability, the ratio of the maximum value (W) of the line width of the non-retroreflective part to the minimum value (C) of the line width of the barcode may be simply expressed as "W / C". ) Is preferably about 50% or less, about 40% or less, about 30% or less, or about 20% or less. The lower limit of such a ratio is not particularly limited, but may be, for example, about 1% or more, about 5% or more, about 7% or more, or about 10% or more. It should be noted that some barcodes may require a certain amount of margin from the viewpoint of readability. For example, in the case of a QR code (trademark), a margin called a quiet zone is required around the outer circumference. However, even if a non-retroreflective part is formed in such a margin, if the non-retroreflective part or the like is adjusted so that the W / C falls within the above-mentioned specific range, the bar It is possible to reduce or prevent a decrease in the readability of the code.

Generally, in order to prevent the above-mentioned misrecognition of the barcode, between the barcode lines other than the portion corresponding to the barcode line (the light-transparent portion colored with black or the like). It is conceivable that the portion corresponding to the above and the margin portion called the quiet zone in the QR code (trademark) are also colored with white or the like to make the light opaque. However, if the bar code is configured in this way, the number of places where the retroreflective part is not reflected increases, so that the retroreflective performance of the retroreflective member is deteriorated and the presence of the bar code which is not retroreflective becomes conspicuous. , The appearance of the article provided with the retroreflective member may be spoiled. The retroreflective member of the present disclosure makes a portion other than the line transparent in a portion corresponding to the line between the barcode lines and a margin portion called a quiet zone in the QR code ™, that is, a barcode region. Therefore, it is possible to reduce or prevent deterioration of the retroreflective performance and the appearance performance of the retroreflective member.

In order to make this W / C easier to understand, an image diagram illustrating the barcode and the non-retroreflective part is shown in FIG. Here, the striped vertical lines at equal intervals correspond to the non-retroreflective part. In FIG. 4, the minimum value (C) of the line width of the barcode is fixed so as to have a ratio of 10, whereas the maximum value (W) of the line width of the non-retroreflective part is 3, 5, 5. It is changed so that the ratio is 7. In FIG. 4, the configurations of W / C of 30% and 50% correspond to the configurations applied to the retroreflective member of the present disclosure.

The barcode applicable to the retroreflective member of the present disclosure is not particularly limited, and includes not only a striped one-dimensional barcode but also a two-dimensional barcode such as a QR code (trademark) or a color barcode. be able to. The color of the bar code line is generally black, but one or more colors other than black may be adopted. The shape of the barcode line is not particularly limited as long as it can be read by the reading device, and is, for example, a rectangular shape, a circular shape, or a linear shape, a curved shape, or an irregular shape having an area recognizable by the reading device. The shape of can be mentioned. These barcodes can be used alone or in combination of two or more. From the viewpoint of readability and the like, the barcode is preferably composed of a black print pattern.

The barcode may be applied directly, for example, by printing on the second main surface of the overlay layer, or a transparent adhesive tape on which the barcode is printed may be attached to the second main surface of the overlay layer. It may be applied indirectly. Alternatively, a transparent display capable of displaying a barcode (for example, a transparent organic EL display) can be adopted. Such a display may be applied to the entire surface or a part of the retroreflective member.

The barcode starts from the part corresponding to the line of the barcode (the part that is light-impermeable with a color such as black) and the part corresponding to the line between the lines of the barcode (the transparent space part). It is configured. These are formed in a negative-positive relationship, and since the reading device uses any one of these parts to read the barcode, any part can be a line of the barcode. Therefore. In the present disclosure, the "bar code line width" is intended to be the width of the bar code line or the width of the space between the bar code lines that can be read by a reading device. For example, FIG. 5 shows a part of a QR code (trademark) which is a two-dimensional bar code. In this case, each of (a) to (d) corresponds to the line width of the bar code. If the lengths of (a) and (b) are the same and the lengths of (c) and (d) are longer than the lengths of (a) and (b), they are displayed in black ( The length of (a) or (b) displayed in black or white can be defined as the minimum value (C) of the line width of the barcode. Here, the white (actually transparent) or black square or rectangular block-shaped portion located below the display (b) or the display (c) as shown in FIG. 5 is also a bar code of the present application. Included in the line.

The size of the line width of the barcode is not particularly limited, and can be appropriately adjusted according to the intended use of the retroreflective member to which the barcode is attached. For example, the minimum value of the line width of the barcode shall be about 0.5 mm or more, about 0.6 mm or more, about 0.7 mm or more, about 0.8 mm or more, about 0.9 mm or more, or about 1 mm or more. It should be about 50 mm or less, about 40 mm or less, about 30 mm or less, about 20 mm or less, about 15 mm or less, about 10 mm or less, about 8 mm or less, about 6 mm or less, about 4 mm or less, about 2 mm or less, or about 1 mm or less. Can be done. The line width of the barcode can be measured using an optical microscope, and the average value of the line widths at at least five points in the barcode can be defined as the line width of the barcode.

In the present disclosure, the “bar code area” refers to an area that linearly surrounds the outermost bar code line. However, if a margin is required around the barcode for reading, the area including this margin is referred to as the "bar code area". For example, when the W / C in FIG. 4 is 30%, it is necessary to read the substantially square area surrounding the outer periphery of the barcode line in the QR code (trademark) and the surrounding QR code (trademark). The area including the quiet zone (the area indicated by the solid line of the substantially square) corresponds to the barcode area.

In some embodiments, the retroreflective members of the present disclosure may further include an infrared light transmissive and visible light opaque cover layer at least on or under the bar code. It may be preferable that the barcode is not visually recognized, for example, from the viewpoint of design. In such cases, it is advantageous to apply such a cover layer to at least the barcode. Since the cover layer has the ability to reduce or shield the transmission of light in the visible region (wavelength: about 400 nm or more and less than about 750 nm), the barcode becomes difficult to see. On the other hand, since this cover layer has the ability to transmit infrared light, particularly light in the near infrared region (wavelength: about 750 nm or more, about 2500 nm or less), for example, a near infrared camera recognizes a barcode. be able to. If the cover layer is arranged on the barcode so as to cover the barcode, the barcode cannot be seen or becomes difficult to see. Further, if the cover layer is arranged under the barcode, for example, between the barcode and the second main surface of the overlay layer, the barcode may be partially reflected in the barcode region or depending on the viewing direction. Although it may be possible to visually recognize the presence of the barcode, the barcode can be made less visible and less noticeable than when the cover layer is not arranged. That is, in any case, the cover layer can reduce or shield the visual visibility of the barcode.

The cover layer is not particularly limited as long as it is a layer capable of exhibiting both infrared light transmissive and visible light impermeable performance. For example, a layer composed of cyan ink, magenta ink, and yellow ink, or a layer composed of ink containing black azo pigment, black perylene pigment, and the like can be used as the cover layer.

The cover layer may be applied directly to, for example, a barcode or overlay layer, or, for example, a transparent substrate (eg, PET film) on which the cover layer is printed may be attached to the barcode or overlay layer. Good. The cover layer is, for example, a bar code, an overlay layer, or a transparent base material, and a colorant such as ink or toner is applied to a known printing such as gravure printing, screen printing, offset printing, electrostatic printing, inkjet printing, and thermal transfer printing. It can be formed by printing using technology. It is advantageous to use inkjet printing or thermal transfer printing because the cover layer can be easily printed on the bird code or the like even in small lot units based on the print image data corresponding to various bird code images. Examples of printers used for inkjet printing include solvent inkjet printers and UV inkjet printers. Examples of printers used for thermal transfer printing include hot melt type thermal transfer printers and sublimation type thermal transfer printers.

Cyan (C) ink, magenta (M) ink, and yellow (Y) ink are generally used as printing inks for inkjet printing, thermal transfer printing, and the like. These inks are conventionally known and generally contain pigments or dyes of corresponding colors, binders or vehicles, and if necessary, further water, organic solvents, dispersants, hardeners, antioxidants, UV absorbers. , Light stabilizer, heat stabilizer, plasticizer, flow improver, leveling agent, antistatic agent, flame retardant and the like may be included.

As inkjet printing inks, for example, genuine ink for JV5 solvent inkjet printer manufactured by Mimaki Engineering Co., Ltd., colorPainter H2-104S genuine ink for solvent inkjet printer manufactured by Seiko Eye Infotech Co., Ltd., UJV500-160UV inkjet printer manufactured by Mimaki Engineering Co., Ltd. Genuine ink for use can be used. As the thermal transfer printing ink, for example, an ink set for 3M (registered trademark) Scotch Master (trademark) Edge II system (thermal transfer printer) can be used.

The thickness of the cover layer may vary, and can be appropriately adjusted in consideration of the required shielding property of the barcode and the like. For example, the thickness of the cover layer can be about 1 micrometer or more, about 2 micrometers or more, or about 5 micrometers or more, and can be about 50 micrometers or less, about 30 micrometers or less, or about 20 micrometers. It can be less than or equal to, or about 10 micrometers or less. The thickness of the cover layer can also be measured using a scanning electron microscope as described above, and the average value of the thickness of any at least 5 points in the cover layer can be defined as the thickness of the cover layer. it can.

In some embodiments, the retroreflective members of the present disclosure may optionally apply one or more additional layers. As additional layers, for example, a protective layer for protecting a barcode or the like, an antifouling layer, a decorative layer, a coloring layer, a bonding layer (primer layer), or a retroreflective member for attaching to an article or a base material. The adhesive layer of the above can be mentioned. These layers can be appropriately prepared using generally known materials, and if necessary, antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers, antistatic agents, flame retardants, etc. can be added. It may be included.

The retroreflective characteristics of the retroreflective member of the present disclosure can be evaluated by the retroreflective coefficient (according to JIS Z 9117) at an observation angle of 0.2 degrees and an incident angle of 5 degrees. Such retro-reflective properties, for example, about 1cd / lx / ^{m 2} or more, about 5cd / lx / ^{m 2} or more, about 10cd / lx / ^{m 2} or more, about 30cd / lx / ^{m 2} or more, or about 50 cd / It can be lp / m ² or more. There is no particular limitation on the upper limit of the retro-reflective properties, for example, about 1500cd / lx / ^{m 2} or less, about 1200cd / lx / ^{m 2} or less, about 1000cd / lx / ^{m 2} or less, about 700 cd / lx / m ^{It can be 2} or less, or about 500 cd / lp / m ² or less.

The retroreflective member of the present disclosure can be adopted for various articles. Articles provided with retroreflective members include, for example, land traffic signs (for example, traffic control signs, general road signs, highway signs, automatic driving guidance signs), water traffic signs used in the sea, lakes, etc. (for example, propulsion). Signs such as buoys that are used to float without force, license plates, signs, road markings, vehicles (especially artificial vehicles such as cars, trains, tractors and other vehicles, ships, aircraft, etc.) ), Unmanned aircraft (for example, drones), robots, seat materials (for example, graphic sheet materials applied to vehicles, etc.), line-of-sight guidance signs, barricades, personal safety products, safety vests, and displays. Can be done. The retroreflective member with a barcode of the present disclosure is retroreflective by the light of a car headlight or the like even in an environment where light is difficult to reach, such as at night or in an indoor parking lot, making it easy to notice the presence of the barcode. In addition, since the barcode is excellent in readability, it can be suitably used even in such an environment.

In some embodiments, the bar coded retroreflective members of the present disclosure can be used for autonomous driving of vehicles, robots, unmanned aerial vehicles and the like. For example, assuming automatic driving of a car, by applying a retroreflective member with a barcode to a road surface and / or a road sign, position information and the like can be obtained from this barcode. For example, even when the position information cannot be confirmed by GPS or the like, accurate position information can be obtained by reading the barcode. Further, such a retroreflective member can be applied to a car, a road sign, or the like. When the retroreflective member is applied to the car, the bar code information of the retroreflective member is read by the camera installed outside the car, and based on the read information, the car is automatically driven. It is also possible to provide various necessary information. When the retroreflective member is applied to, for example, a guide sign for automatic driving installed outside the vehicle, the bar code information of the retroreflective member is read by a camera installed inside the vehicle or on the side of the vehicle. Based on the read information, various necessary information can be provided to the vehicle to automatically drive the vehicle.

In some embodiments, the bar coded retroreflective member of the present disclosure can be used for signs such as general road signs, or signs. For example, signs or signs installed on the side of a road generally have retroreflective performance from the viewpoint of safety. Such signs or signs include information on road traffic or construction, information on scenic spots, store information such as restaurants or goods stores, information on various facilities, detailed information on regional information, etc. When the retroactive reflective member of the present disclosure equipped with the barcode is adopted, for example, a passenger of the car attaches a sign or a signboard with a barcode on the side of the road to a barcode mounted on a smartphone or the like. Various information can be easily obtained by reading with a reader. Even at night, the sign or signboard provided with the retroreflective member with a barcode of the present disclosure can easily notice the existence of the barcode due to the retroreflective based on the headlight of a car or the like, so that information from the barcode can be easily obtained. can do.

Specific embodiments of the present disclosure will be illustrated in the following examples, but the present invention is not limited thereto.

The products used in this example are shown in Table 1 below.

<Example 1>
On the Adobe Illustrator ™, draw a barcode (QR code ™ (trademark) (25 cells x 25 cells)) with a width of 40 mm and a height of 40 mm shown in FIG. 7 with the halftone dot area ratio of black as 100%. Printed image data in eps format was generated. This printed image data was printed on the base material side of the transparent adhesive tape using a JV5 solvent inkjet printer manufactured by Mimaki Engineering Co., Ltd. and black ink to create a barcode. The minimum value (C) of the line width of the obtained barcode was about 1.6 mm. Next, a transparent adhesive tape on which a barcode was printed was attached to the side of the retroreflective sheet 1 having a pattern as shown in FIG. 3D to prepare a test sample of Example 1. ..

<Comparative example 1>
A test sample of Comparative Example 1 was prepared in the same manner as in Example 1 except that the barcode was changed to a barcode having a width of 20 mm and a height of 20 mm (QR code (trademark) (25 cells × 25 cells)). .. The minimum value (C) of the line width of the obtained barcode was about 0.71 mm.

<Example 2>
The barcode was changed to a barcode having a width of 20 mm and a height of 20 mm (QR code (trademark) (25 cells × 25 cells)), and the retroreflective sheet 2 having a pattern as shown in FIG. 3 (c). A test sample of Example 2 was prepared in the same manner as in Example 1 except that the above was used. The minimum value (C) of the line width of the obtained barcode was about 0.71 mm.

(Barcode reading test 1: Visible light)
As shown in FIG. 6, the position is inclined by about 30 degrees with respect to the normal of the retroreflective surface (barcode side surface) of each test sample which is a retroreflective member, and the retroreflective reflection is performed. An LED light source (Energizer (trademark) PLED23A, Energizer Holdings, Inc. (USA)) and a barcode reading camera (iPhone (trademark) 7, Apple (USA)) were arranged at a position about 150 cm away from the surface. After irradiating the retroreflective surface with light from the LED light source, it was evaluated whether the barcode could be read by the camera, and the results are shown in Table 2. Here, the case where the barcode can be read is described as "OK", and the case where the barcode cannot be read is described as "impossible". In addition, photographs of the barcode at the time of the test are shown in FIGS. 7 to 9. FIG. 7 corresponds to Example 1, FIG. 8 corresponds to Comparative Example 1, and FIG. 9 corresponds to Example 2.

<Example 3>
Cyan halftone dot area ratio is 100%, magenta halftone dot area ratio is 100%, and yellow halftone dot area ratio is 100% in a square area of width 100 mm × height 100 mm on Adobe Illustrator ™. And generated print image data in eps format. This printed image data was printed on the base material side of the transparent adhesive tape using a JV5 solvent inkjet printer manufactured by Mimaki Engineering Co., Ltd. and cyan ink, magenta ink, and yellow ink. This was attached to a transparent polyester film (manufactured by Mitsui Chemicals Tohcello Co., Ltd.) with a thickness of 38 micrometers. Two sheets of this film were prepared, and an infrared light-transmitting and visible light-impermeable cover layer prepared by superimposing them was arranged so as to cover the barcode with respect to the test sample obtained in Example 2. Then, the test sample of Example 3 was prepared. As shown in FIG. 10, the obtained test sample could not read the barcode in the barcode reading test 1 using visible light.

<Comparative example 2>
A test sample of Comparative Example 2 was prepared in the same manner as in Example 3 except that the test sample obtained in Comparative Example 1 was used. In the test sample of Comparative Example 2, the barcode could not be read in the barcode reading test 1 using visible light.

(Barcode reading test 2: Infrared light)
As shown in FIG. 11, the position is inclined by about 40 degrees with respect to the normal of the retroreflective surface (the surface on the bar code side) of each test sample which is a retroreflective member, and the retroreflective reflection is performed. An infrared LED light source (MG-M IR850, distributor MG-MART) having a wavelength of 850 nm is placed at a position about 18 cm away from the surface, and the position is inclined by about 30 degrees and the retroreflective surface. An infrared camera (web camera webcam webcamera aa0000080a02, distributor Onrifu Co., Ltd.) was placed at a position about 17 cm away from the distance. The LED mounted on the infrared camera was used without operation. The retroreflecting surface is irradiated with light from an infrared LED light source, a bar code image taken by an infrared camera is displayed on a liquid crystal monitor (EIZO, 24 inches, model number EV2450), and the image is displayed on a bar code reading camera (iPhone (iPhone). (Trademark) 7, Apple Inc. (USA)) evaluated whether it could be read, and the results are shown in Table 3. Here, the case where the barcode can be read is described as "OK", and the case where the barcode cannot be read is described as "impossible". In addition, a photograph of the barcode at the time of the test is shown in FIG. FIG. 12 (a) corresponds to Example 3, and FIG. 12 (b) corresponds to Comparative Example 2.

It will be apparent to those skilled in the art that the above embodiments and examples can be modified in various ways without departing from the basic principles of the present invention. It is also apparent to those skilled in the art that various improvements and modifications of the present invention can be carried out without departing from the spirit and scope of the present invention.

100, 200 Retroreflective member 102, 202 Observer 104,204 Barcode 110, 210 Retroreflective layer 112, 212 Retroreflective element 114, 214 Structured surface 116, 216 First main surface 117, 217 Second Main surface 118, 218 Overlay layer 130 First adhesive layer 132 First adhesive 134 Barrier layer 136 First base material 138, 238 Low refractive index layer 230 Structured adhesive layer 240 Structured adhesive liner 250 2 Adhesive layer 260 2nd base material W Maximum line width of non-retroreflective part C Minimum line width of bar code

Claims (13)

It has a retroreflective layer including an overlay layer having first and second main surfaces and a plurality of retroreflective elements arranged on the first main surface.
A retroreflective member in which a patterned non-retroreflective portion and a retroreflective portion can be visually recognized from the second main surface side of the overlay layer.
A barcode is provided on the second main surface of the overlay layer.
The maximum value of the line width of the non-retroreflective portion in the bar code region and where the bar code line is not applied is 50% or less of the minimum value of the line width of the bar code. ,
Retroreflective member. The retroreflective member according to claim 1, wherein the barcode is a two-dimensional barcode. The retroreflective member according to claim 1 or 2, which has a low refractive index layer on the plurality of retroreflective elements. The retroreflective member according to claim 3, wherein the low refractive index layer is an air layer. The retroreflective member according to claim 3 or 4, wherein the low refractive index layer is formed of a barrier layer or a structured adhesive layer. The retroreflective member according to any one of claims 1 to 5, wherein the retroreflective element is a cube corner element. The retroreflective member according to any one of claims 1 to 6, wherein the minimum value of the line width of the barcode is 0.5 mm or more. The retroreflective member according to any one of claims 1 to 7, wherein the barcode is composed of a black print pattern. The retroreflective member according to any one of claims 1 to 8, wherein a portion other than the line of the barcode is transparent in the barcode region. The retroreflective member according to any one of claims 1 to 9, further comprising a cover layer that is transparent to infrared light and opaque to visible light. The retroreflective member according to any one of claims 1 to 10, wherein the barcode provides information necessary for automatic driving. An article comprising the retroreflective member according to any one of claims 1 to 11. The article of claim 12, which is a sign, license plate, sign, road marking, or vehicle.