JP4059684B2 - Retroreflective article having image formed thereon and method for producing the same - Google Patents

Description

【０１５１】
また、鏡面層金属が非鏡面化処理後にその場で残留して像が形成していることの確認としてＥＰＭＡ分析法により、以下の試料の像部分の分析を行った。
分析試料１： 実施例１で用いた出発原料１の鏡面反射層
分析試料２： 試料１を水酸化ナトリウムでエッチングしてアルミニウム層を除去した試料。
分析試料３： 実施例１で作成した試作品１の像形成部分
【０１５２】
図１３〜１５に分析試料１〜３の分析結果を図示する。分析試料１にはアルミニウムが存在し反射素子を覆っているが、１Ｎ−水酸化ナトリウム水溶液でエッチングした分析試料２にはアルミニウムが存在せず、像の部分で反射素子が露出していることを示している。一方、本発明の方法により像が形成された分析試料３においては、像形成部分が非鏡面化されていることが目視により確認できるが、アルミニウムが残留しておりその場で非鏡面化されていることを示している。
【０１５３】
本発明の記載により像が形成された試作品１〜６はいずれも優れた視認性と耐久性を示したが、比較例に用いた印刷像は特に耐久性に劣っていた。
【図面の簡単な説明】
【図１】 従来技術による封入型再帰反射物品
【図２】 本発明の封入型再帰反射物品の工程を説明する図
【図３】 本発明の封入型再帰反射物品の工程を説明する図
【図４】 本発明の封入型再帰反射物品の工程を説明する図
【図５】 本発明の封入型再帰反射物品の工程を説明する図
【図６】 本発明の封入型再帰反射物品の工程を説明する図
【図７】 本発明の封入型再帰反射物品の工程を説明する図
【図８】 従来技術による鏡面反射式プリズム型再帰反射物品
【図９】 本発明のプリズム型再帰反射物品の工程を説明する図
【図１０】 本発明のプリズム型再帰反射物品の工程を説明する図
【図１１】 本発明のプリズム型再帰反射物品の工程を説明する図
【図１２】 本発明のプリズム型再帰反射物品の工程を説明する図
【図１３】 分析試料１の金属分析結果
【図１４】 分析試料２の金属分析結果
【図１５】 分析試料３の金属分析結果
【符号の説明】
１ 入射光
２ 表面層
３ 印刷層(像)
４ 固着層
５ 微小硝子球
６ 焦点層
７ 鏡面反射層
８ 接着剤層
９ 剥離材層
１０ 光反応性樹脂層
１１ 光遮蔽マスク
１２ プリズム層
１３ 非鏡面化部分[0002]
[Industrial application fields]
[0003]
The present invention relates to a retroreflective article on which an image is formed and a method for manufacturing the same, and relates to a retroreflective article on which an image is formed by partially de-mirroring a specular reflection layer and a method for manufacturing the retroreflective article.
[0004]
Specifically, the present invention relates to signs such as road signs, construction signs, etc., license plates of vehicles such as automobiles and motorcycles, safety materials such as clothing and life preservers, markings such as signs, visible light, laser light or infrared. The present invention relates to a retroreflective article in which an image is formed by partially despecularizing a specular reflection layer of a retroreflective element useful for a reflection plate of a light reflection type sensor or the like, and a manufacturing method thereof.
[0005]
In particular, the radio wave transmission portion was formed by partially de-mirroring the specular reflection layer of the retroreflective element, which is useful for retroreflective articles in which non-contact type IC communication devices with thin-layer antennas are laminated. The present invention relates to a retroreflective article and a manufacturing method thereof.
[0006]
More specifically, a first layer comprising a substantially transparent layer having a flat first surface and a second layer comprising a retroreflective element layer having a second surface from which the specular reflection layer is exposed. Using a retroreflective article consisting of
A. A step of installing a photoreactive resin layer on the second surface of the specular reflection layer
B. Process of partially reacting photoreactive resin by selective light irradiation
C. Step of partially removing the non-reactive region of the photoreactive resin layer
D. Forming an image by making the exposed part of the specular reflection layer non-specular in situ
The present invention relates to a retroreflective article on which an image is formed and a method for producing the same.
[0007]
[Prior art]
[0008]
Conventionally, various methods have been proposed for forming an image on a retroreflective article.
[0009]
As a conventionally known method of forming an image, a method of forming an image by a printing method using printing ink on the surface (first surface) or the inner surface of the surface protective layer is generally used. US Pat. Nos. 3,154,872, 3,801,183, 4,082,426 (Japanese Patent Laid-Open No. 53-068596), and 4,097,838 are disclosed as printing methods. Here, this concrete description is replaced by citation of this document.
[0010]
Furthermore, a method of directly placing an image on a retroreflective element is also known.
[0011]
In Lytle's Special Table No. 10-500230 retroreflective product and its manufacture,
(A) supporting a layer of microspheres on a carrier;
(B) The first part of the microsphere layer is supported so that it has a reflective metal layer functionally coated behind it and the second part does not have such a reflective metal layer. Selectively depositing a reflective metal layer on the layer of microspheres;
(C) partially embedding a layer of microspheres in the first major surface of the binder layer;
(D) removing the carrier from the microsphere layer such that the microsphere layer remains partially embedded in the first major surface of the binder layer to form a retroreflective product having first and second segments. Wherein the first segment has a deposited reflective metal layer functionally disposed behind the embedded portion of the microsphere;
Is disclosed.
[0012]
In JP-A-4-229244 of Martin, the adhesive layer is partially formed on the metal adhesion layer formed on the surface of the retroreflective microprism, and the metal layer not protected by the adhesion layer is peeled off to In particular, a method of forming a retroreflective microprism sheet without a metal layer is disclosed. Further, it is described that the adhesive layer (protective coating material) to be partially installed is preferably a pressure-sensitive adhesive that is not significantly adversely affected in the solvent treatment stage in the subsequent process. Furthermore, a printing method is described as a method of installation.
[0013]
Furthermore, in Martin JP-A-1-231004, by partially forming an adhesive layer on the metal adhesion layer formed on the retroreflective microprism surface, the metal layer not protected by the adhesion layer is peeled off. , A method of forming a retroreflective microprism sheet that is not partially provided with a metal layer, and a metallization after applying a coating material partially on the surface of the retroreflective microprism, and then partially covering A method of forming a retroreflective microprism sheet that is not partially provided with a metal layer by removing the prepared material is disclosed.
[0014]
In addition, a method of removing the vapor deposition layer with a laser is generally used.
[0015]
U.S. Pat. No. 4,200,875 to Galanos discloses a method of forming an image with a predetermined pattern on an exposed lens type retroreflective sheet.
[Problems to be Solved by the Invention]
[0016]
An object of the present invention relates to a retroreflective article on which an image is formed and a method for producing the same, and relates to a novel retroreflective article on which an image is formed by partial non-specularization of a specular reflection layer and a method for producing the same.
[0017]
As a conventionally known method of forming an image, a method of forming an image by a printing method using printing ink on the surface (first surface) or the inner surface of the surface protective layer is generally used. However, in such a method using printing ink, it is difficult to obtain an image having excellent durability because deterioration of the resin layer forming the image is easily accelerated by the entry of light or water from the outside.
[0018]
Further, an adhesive layer is partially formed on the metal adhesion layer formed on the retroreflective microprism surface as disclosed in Martin's Japanese Patent Laid-Open Nos. 4-229244 and 1-231004. In the method of forming a retroreflective microprism sheet that is not partially provided with a metal layer by peeling off the metal layer that is not protected by the adhesive layer, the adhesive layer must be partially provided by a printing method or the like. Therefore, the adhesive containing the solvent flows out along the grooves between the prisms, and it is difficult to form a clear image. In addition, the prism is deformed by the solvent and the retroreflective performance is lowered.
[0019]
In addition, a method of removing the vapor deposition layer with a laser is generally used. However, the method of forming an image by the laser method has a problem that the retroreflective performance is deteriorated because the microscopic glass spheres and prisms which are reflective elements are partially destroyed. Furthermore, since the diameter of the laser beam that can be used is small, an image that can be formed is obtained as a collective image of minute dots, so that it is difficult to obtain a clear image and it is difficult to form a wide-range image.
[0020]
An object of the present invention is to provide a novel retroreflective article in which an image is formed by partially non-specularizing a specular reflection layer and a method for manufacturing the same, in order to improve the above-described problems of the prior art. It is.
[0021]
[Means for Solving the Problems]
[0022]
The present invention provides a first layer comprising a substantially transparent layer having a flat first surface and a second layer comprising a retroreflective element layer having a second surface from which the specular reflection layer is exposed. Using a retroreflective article consisting of
A. A step of installing a photoreactive resin layer on the second surface of the specular reflection layer
B. Process of partially reacting photoreactive resin by selective light irradiation
C. Step of partially removing the selected region of the photoreactive resin layer
D. Forming an image by making the exposed part of the specular reflection layer non-specular in situ
The present invention relates to a retroreflective article on which an image is formed and a method for producing the same.
[0023]
The types of retroreflective articles that can be used in the present invention have a first layer comprising a substantially transparent layer with a flat first surface and a second surface with an exposed specular reflection layer. Any retroreflective article comprising a retroreflective element layer and a second layer can be selected as appropriate, but the retroreflective element layer is an encapsulated lens type, a capsule lens type, and a specular reflection type prism type retroreflective element. A retroreflective article made of a retroreflective element selected from the group is preferred.
[0024]
As an example of an encapsulated retroreflective element, a retroreflective sheet made of a microglass spherical retroreflective element with a retroreflective element diameter of 30 to 500 μm constituting the retroreflective part is preferable, and the surface is smooth and transparent. Covered with layers. Reflective elements with a diameter of less than 30 μm are unfavorable due to excessive divergence of light due to diffraction effects, resulting in poor retroreflective performance. Reflective elements with a diameter of more than 500 μm are undesirably thick and formed. This is not preferable because the sharpness of the image is lowered.
[0025]
As an example of the capsule lens type retroreflective element, a retroreflective sheet made of a micro glass sphere type retroreflective element having a retroreflective element diameter of 30 to 500 μm constituting the retroreflective portion is preferable, and a plastic film constituting the surface protective layer is preferable. Has a smooth surface and is transparent. As with the encapsulated lens type retroreflective sheet, the reflective element with a diameter of less than 30 μm is unfavorable because the light divergence due to the diffraction effect becomes excessive and the retroreflective performance deteriorates. Is excessive, and the sharpness of the formed image is lowered.
[0026]
An example of a specular reflection type prism-type element is a retroreflective sheet consisting of a cube-corner type retroreflective element with a retroreflective element height of 50 to 500 μm constituting the retroreflective part, and the reflective surface of the element is a metal thin film Is a retroreflective sheet that has been mirror-finished to form a specular reflection layer. In cube corner reflectors with an element height of less than 50μm, light divergence due to the diffraction effect becomes excessive and the retroreflective performance deteriorates, which is not preferable. In cube corner reflectors with a height of over 500μm, the sheet thickness is excessive. In addition, the sharpness of the formed image is lowered, which is not preferable.
[0027]
As a preferred embodiment of the specular reflection type prism-type element, the bottom surface formed by intersecting V-shaped grooves having substantially symmetrical cross sections is a triangle, and three side surfaces intersecting at substantially right angles. A pair of specular reflection type triangular pyramidal prism type elements separated by each other is preferable.
[0028]
Also, the optical axis of the specular reflection type prism-type element can be tilted to improve the incident angle characteristic during retroreflection. The angle of inclination is 0.5 to 12 degrees, preferably 0.6 to 10 degrees, more preferably 0.7 to 1.5 degrees, and the direction of inclination is a pair of specular reflection type triangular pyramids facing each other. Either the direction in which the optical axes of the prism-type elements approach each other or the direction in which they move away may be used.
[0029]
As an example of a preferable specular reflection type triangular pyramidal prism type element, triangular pyramidal cube corner retroreflective elements protruding on a common bottom surface (XX ′) are mutually connected on the bottom surface (XX ′). They share one base and are arranged in a close-packed manner on the bottom face relative to each other, and the bottom face (XX ′) is a number of the bases (x−x) shared by the triangular pyramid-shaped reflective element. , X,...), And the two triangular-pyramidal reflective elements facing each other are shared by the bases (x, x,...) On the bottom surface (XX ′). ..) Are formed in pairs of substantially identical shapes facing each other so as to be symmetrical with respect to a plane (YY ′, YY ′,...) Perpendicular to the bottom surface. The triangular pyramid-shaped reflecting element includes substantially the same pentagonal inclined surfaces (c1, c2) having the shared base (x, x,...) As one side, and the triangular pyramid. The c1 plane or the c2 plane starting from the apex (H) of the reflective reflector is defined as one side, and one ridge line of the triangular pyramid reflective element is shared, and this c1 is defined as one side. It is composed of substantially the same quadrangular inclined surfaces (a1 surface, b1 surface; a2 surface, b2 surface) crossing at right angles to the surface or c2 surface, and from the apex (H) of the triangular pyramid reflector, the triangle The height (h) to the bottom surface (XX ′) including the base (x, x,...) Of the pentagonal inclined surface (c1, c2) of the cone-shaped reflecting element is the triangular pyramid shape. From the vertex (H) of the reflective element, a substantially horizontal surface (z, w) including the bases (z, w) of other inclined surfaces (a1, b1, a2, and b2 surfaces) of the triangular pyramidal reflective element ( A specular reflection type prism type element characterized by being substantially larger than the height (h ') up to the virtual plane ZZ') can be given. A triangular pyramidal cube corner retroreflective sheet including such an element is described in International Patent Publication No. WO 01 / 57560A1, and here, this specific description is used instead of this reference.
[0030]
As an example of a more preferable specular reflection type prism-type element, the triangular pyramid-shaped cube corner retroreflective element has three substantially perpendicular V-shaped grooves crossing each other so that they are substantially perpendicular to each other. One base (S-S ') where a pair of triangular-pyramidal cube-corner retroreflective elements separated by crossing side surfaces (a1, b1, c1; a2, b2, c2, etc.) The pair of triangular-pyramidal retroreflective elements are arranged in a close-packed manner so as to protrude on one side of the upper side, and the side surfaces (c1 surface, c2 surface) facing each other have one base (x) The bottom surfaces (S-S ') are the base (z, z) and the other side of one side (a1, plane a2) of the pair of triangular pyramid retroreflective elements. A common plane that includes both the bottom sides (y, y) of (b1 plane, b2 plane) The pair of triangular-pyramidal retroreflective elements that share ()) have different shapes on the side surfaces (c1, c2) facing each other, and the height from the plane (S-S ') to the apex. Specular reflection type prism type elements characterized in that are different from each other can be mentioned. A triangular pyramid cube corner retroreflective sheet including such an element is described in Japanese Laid-Open Patent Publication No. 20001-264525, and here, this specific description is used instead of this reference.
[0031]
As the material constituting the specular reflection layer of the retroreflective element, a metal film selected from aluminum, an aluminum-magnesium alloy, an aluminum-manganese alloy, silver, copper, and nickel can be provided alone or in combination. As a method for installing the specular reflection layer, a vapor deposition method, a sputtering method, an electroplating method, a chemical plating method, or a metal-like resin layer placement method with an ink or paint having a metallic luster appearance can be appropriately employed. Moreover, the thickness of the specular reflection layer to be installed can be 0.2 to 2 μm, preferably 0.5 to 1.5 μm.
[0032]
The specular reflection layer is preferably an aluminum specular reflection layer. The apparatus for continuous vapor deposition of an aluminum specular reflection layer is a vacuum container capable of maintaining a degree of vacuum of about 7 to 9 × 10 −4 mmHg, a base sheet installed therein, and a surface protective layer laminated on the light incident side surface The unwinding device for unwinding the prism raw sheet, the winding device for winding the vapor-deposited prism original sheet, and the heating device between them, which can melt aluminum with an electric heater in a graphite crucible It has become more. Pure graphite pellets having a purity of 99.99% by weight or more are charged into the graphite crucible, and are melted and vaporized under conditions of, for example, an AC voltage of 350 to 360 V, a current of 115 to 120 A, and a processing speed of 30 to 70 m / min. The specular reflection layer can be deposited on the surface of the retroreflective element with a thickness of 0.2 to 2 μm, for example, by the converted aluminum atoms.
[0033]
In the present invention, the first layer comprising a substantially transparent layer having a flat first surface has a retroreflective element diameter of 30 to 500 μm constituting a retroreflective portion in the case of an encapsulated retroreflective element. In the case of a capsule lens type retroreflective element, it is separated by an air layer through a partial sealed enclosure structure. Further, in the case of a specular reflection type prism type element, it may be configured as an independent layer so as to be in close contact with the reflection element layer, or may be configured as the same layer as the resin layer constituting the prism type element. Also good.
[0034]
The thickness of the first layer in the present invention can be appropriately selected within a range that does not hinder the visibility of the formed image, which is the object of the present invention, but as a preferred thickness, in any type of element, 10-2000 micrometers, More preferably, 20-100 micrometers is illustrated.
[0035]
Furthermore, it is desirable to use a resin having excellent transparency in order to improve the retroreflection performance and the visibility of the image as the resin that can be used for the first layer. As the transparency of the first layer used in the present invention, in the case of a colorless resin which is not colored, a light transmittance of 50 to 98%, preferably 60 to 97% can be used. As a method for measuring the light transmittance in the present invention, an SC-2-CH type tester manufactured by Suga Test Instruments Co., Ltd. was used based on the object color measurement method of JIS Z8722.
[0036]
In the present invention, as the resin that can be used for the first layer including the substantially transparent layer having the flat first surface, various transparent plastic resins can be used, for example, polycarbonate resin, Vinyl chloride resin, (meth) acrylic resin, epoxy resin, polystyrene resin, polyester resin, fluorine resin, polyolefin resin such as polyethylene resin and polypropylene resin, cellulose resin, polyurethane resin, and the like can be used alone or in combination. As a specific method used in combination, a monomer used for producing each resin can be used as a copolymer resin, mixed and used by being laminated.
[0037]
Furthermore, for the purpose of improving the weather resistance, an ultraviolet absorber, a light stabilizer, an antioxidant and the like can be used alone or in combination. Furthermore, various organic pigments, inorganic pigments, fluorescent pigments, dyes, fluorescent dyes and the like can be contained as colorants.
[0038]
Next, in the present invention, a first layer including a substantially transparent layer having a flat first surface and a retroreflective element layer having a second surface from which the specular reflection layer is exposed are included. Using a retroreflective article consisting of the second layer,
A. A step of installing a photoreactive resin layer on the second surface of the specular reflection layer
B. Process of partially reacting photoreactive resin by selective light irradiation
C. Step of partially removing the selected region of the photoreactive resin layer
D. Forming an image by making the exposed part of the specular reflection layer non-specular in situ
The process of forming an image by the method will be described below.
[0039]
As a step of installing a photoreactive resin layer on the second surface of the specular reflection layer in step A, continuous or sheet-like screen printing, gravure printing, Direct coating methods such as various coating methods and spraying methods can be adopted.
[0040]
At this time, it is possible to limit the area where the photoreactive resin is installed in advance and to install it partially by a printing method or a coating method. In that case, it is necessary to adjust the viscosity appropriately so that a proper viscosity is obtained so that a clear image is formed. As a preferable viscosity, 5000-10000 cps can be illustrated, for example. Also, a solvent that does not attack the device should be used depending on the resin used.
[0041]
Or the method of laminating | stacking a sheet-like photoreactive resin on a specular reflection layer by applying a pressure with a heat roll is also employable.
[0042]
In the present invention, it is desirable that the thickness of the photoreactive resin layer on the second surface of the specular reflection layer to form an image is 10 to 200 μm. More preferably, 30-100 micrometers is desirable.
[0043]
When the thickness is less than 10 μm, when the specular reflection layer is partially removed, the agent for removing the specular reflection layer penetrates through the photoreactive resin layer and reacts with the specular reflection layer. On the other hand, when the thickness exceeds 200 μm, light is easily scattered inside the photoreactive resin layer during selective photoreaction, and it is not preferable because it is difficult to form a clear image. In addition, when the specular reflection layer is partially made non-specular, it becomes difficult to enter the agent for processing the specular reflection layer, and it is difficult to remove the specular reflection layer, which makes it difficult to form a clear image. Therefore, it is not preferable. Further, it is not preferable because the thickness of the photoreactive resin layer is excessive and it is difficult to obtain a flexible sheet product.
[0044]
In the present invention, photopolymerizable, photocondensation, photocrosslinking, and photodegradable resins can be used as appropriate for the photoreactive resin layer placed on the second mirror reflection layer. These resins cause changes in physical properties such as changes in solubility, phase change from liquid to solid, and changes in adhesiveness when irradiated with light, enabling partial image formation.
[0045]
As a first example of a photoreactive resin that can be used in the present invention, a so-called acrylic prepolymer used as a UV curable ink is used as a vehicle, and a reactive monomer, a photopolymerization initiator, and an auxiliary agent are used as the vehicle. UV curable resin to which a kind is added can be used. As the vehicle, acrylic polymers such as polyester acrylate, epoxy acrylate and urethane acrylate having a weight average molecular weight of about 1000 to 5000, modified alkyd resin having an acryloyl group introduced, and the like can be used.
[0046]
Examples of the polyester acrylate include a prepolymer having acryloyl groups introduced at both ends of a polyester resin obtained from adipic acid and 1,6-hexanediol. As an example of the epoxy acrylate, a prepolymer obtained by reacting glycidyl groups at both ends of the epoxy resin with acrylic acid can be used. Examples of polyurethane acrylates include prepolymers in which both ends of a polyester resin obtained from adipic acid and 1,6-hexanediol are reacted with tolylene diisocyanate resin and subsequently reacted with 2-hydroxyethyl acrylate. Can be used.
[0047]
Examples of reactive monomers that can be used include polyfunctional acrylates such as diethylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, and pentaerythritol triacrylate. be able to.
[0048]
As the photopolymerization initiator that can be used for the photoreactive resin, those that absorb UV light and efficiently generate radicals effective for the polymerization reaction are preferable. For example, aromatic carbonyl compounds such as various benzoin derivatives, 2,2-dimethoxy-2-phenylacetophenone, benzophenone, thioxanthone, etc. that generate radicals by hydrogen abstraction by UV light irradiation in the presence of a hydrogen donor are used. be able to. Furthermore, radicals can be generated efficiently by adding amines.
[0049]
Furthermore, various pigments, thixotropy imparting agents, thermal polymerization inhibitors, waxes and the like can be added.
[0050]
These UV curable resins can be placed on the specular reflection layer by various printing methods such as screen printing, gravure printing, and various coating methods.
[0051]
As a second example of the photoreactive resin that can be used in the present invention, a so-called negative diazo resin photosensitive material obtained by condensing p-diazophenylamine with paraformaldehyde to form an aromatic sulfonate. Materials can be used.
[0052]
The above aromatic sulfonate is preferably used by being mixed with a binder polymer such as 2-ethylhydroxymethacrylate-methylmethacrylate copolymer resin. Such a photoreactive resin can be insolubilized by decomposition of a diazo group by light irradiation.
[0053]
As a third example of the photoreactive resin that can be used in the present invention, a photopolymerization composed of an acrylic polymer binder having an aryl group introduced in the side chain, a polyfunctional acrylate monomer, and a photopolymerization initiator is used. Type photopolymer can be used.
[0054]
Examples of the acrylic monomer that can be used in the acrylic polymer binder having an aryl group introduced in the side chain include various acrylic acids, methacrylic acid, acrylic esters, methacrylic esters, and aryl methacrylate.
[0055]
Examples of polyfunctional acrylate monomers that can be used in the present invention include diethylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, and the like. be able to.
[0056]
Examples of photopolymerization initiators that can be used in the present invention include various organic peroxides, diphenyliodonium salts, N-phenylglycine, trichloromethyltriazine, iron arene complexes, and the like, and thiopyrylium. It is preferably used in combination with a photosensitizer such as a salt, a ketocoumarin dye, and a thioxanthene dye.
[0057]
As an example of the fourth photoreactive resin that can be used in the present invention, it is generally used as a photoresist material to form an etching-resistant thin film by light irradiation to perform a partial etching process of metal. The photoreactive resin for resists to be used can be mentioned.
[0058]
Specific examples of the photoreactive resin for resist include a photosensitizer obtained by esterifying ortho-naphthoquinonediazosulfonic acid with a novolac resin, 2,3,4-trihydroxybenzophenone, tetrahydroxybenzophenone, and the like, and a cresol type novolac resin. And a positive type photoresist resin in which is mixed.
[0059]
The ortho-naphthoquinonediazide compound is decomposed by light irradiation and converted into an alkali-soluble 3-indenecarboxylic acid type compound via a carbene and ketene structure. The ortho-naphthoquinonediazidosulfonyl group acts as a dissolution inhibitor for novolak resins before light irradiation, but acts as a dissolution accelerator after photolysis, increasing the solubility of the light-irradiated part in alkaline aqueous solution. Thus, only the exposed part is dissolved and removed to form a positive image.
[0060]
The positive photoresist resin of the type described above has excellent resolution and alkali resistance from the ultraviolet region to the visible light region, and is therefore excellent in etching suitability, and the formation of the retroreflective article on which the image of the present invention is formed. Is preferable.
[0061]
Examples of water-soluble photoresist materials include materials in which 2 to 9% dichromate is added to water-soluble polymers such as casein, glue, and polyvinyl alcohol.
[0062]
A cinnamic acid resist material can also be used. This resist material is obtained by reacting cinnamate chloride having a photodimerization type photosensitive group with polyvinyl alcohol, and generates insoluble resin by irradiating with ultraviolet rays of 230 to 450 nm. Furthermore, it is preferable to add 5-nitroacenaphthene, 1,2-benzanthraquinone or the like as a photosensitizer.
[0063]
Furthermore, a rubber-based resist material can also be used. This resist material is obtained by adding a bisazide compound as a photosensitive agent to rubber such as natural rubber, cyclized polyisoprene, or polybutadiene. Upon irradiation with light, the azide group decomposes to become a reactive nitrene intermediate, which reacts with the rubber and becomes insoluble.
[0064]
Examples of bisazido compounds used in these rubber-based resist materials include 2,6-di- (4′-azidobenzylidene) cyclohexane and 2,6-di- (4′-azidobenzylidene) -4-methylcyclohexane. Can do.
[0065]
Since these rubber-based resist materials are excellent in chemical resistance, durability and resolution, they are preferable for forming a retroreflective article on which an image of the present invention is formed.
[0066]
A preferred example of the fifth photoreactive resin that can be used in the present invention is a sheet-like light sold as a product for use in the formation of printed wiring generally used for electronic equipment as a dry film photoresist. It is a reactive resin. Usually, the protective film is sold in a sandwiched form on both sides, and the protective film is peeled off and laminated with the mirror reflection layer of the retroreflective article used in the present invention.
[0067]
The material used for the dry film photoresist is composed of a binder polymer, a polyfunctional monomer, a polymerization initiator, a thermal polymerization inhibitor, an adhesion promoter, a plasticizer, and the like. As an example of the binder polymer, a (meth) acrylate resin containing methyl methacrylate as a main component, or styrene, acrylonitrile and a (meth) acrylic acid copolymer can be used. As the polymerization initiator, a benzoin derivative, 2,2-dimethoxy-2-phenylacetophenone, or the like can be used.
[0068]
This dry film photoresist becomes insoluble in an alkaline developer upon irradiation with ultraviolet rays. Examples of the thickness of the sheet that can be used include 10 to 100 μm, preferably 10 to 50 μm. Such a sheet-like photoreactive resin is excellent in resolution because it can form a uniform film, and is particularly preferable for forming a retroreflective article on which an image of the present invention is formed. In addition, since no solvent is used, deformation of the retroreflective element due to the solvent does not occur through the specular reflection layer of the retroreflective article, which is particularly preferable in the case of a prism type retroreflective article using polycarbonate resin or vinyl chloride resin.
[0069]
Care must be taken to avoid element deformation due to heat when laminating Drifalm photoresist and the specular reflection layer of the retroreflective article by thermocompression bonding. For example, in the case of a specular reflection type prism-type retroreflective article using a polycarbonate resin as a prism layer, a heating temperature of 50 to 90 degrees and a pressure of 2 kg / cm²These conditions can be exemplified. When the heating temperature is low, the adhesion with the specular reflection layer is insufficient and the developer enters, which is not preferable. When the heating temperature is too high, the retroreflective performance is deteriorated due to deformation of the prism element. The crimping temperature and pressure should be appropriately selected depending on the heat deformation temperature of the resin and resist film used in the retroreflective article.
[0070]
The photoreactive resin placed as described above is subjected to photopolymerization, photocondensation, photocrosslinking, and photolysis by selectively irradiating with light as Step B, in a pattern that matches the desired image. The photoreactive resin layer can be removed.
[0071]
As a selective light irradiation method, a method using a light shielding mask on which an image pattern is printed or cut out, a method of continuously forming an image using a laser beam, or the like can be used. As the laser beam to be used, a g-line having a wavelength of 436 nm, which is a visible light laser, and an i-line having a wavelength of 365 nm, an excimer laser line having a wavelength of 248 nm generated by KrF, or the like can be used.
[0072]
In the present invention, the light used for the reaction of the photoreactive resin is not particularly limited to visible light as long as photopolymerization, photocondensation, photocrosslinking, and photolysis can be performed, but ultraviolet light, infrared light, Electromagnetic waves such as far infrared rays and X-rays are also included.
[0073]
The photoreactive resin subjected to the selective photoreaction described above uses various solvents in Step C, and in the case of a photopolymerizable, photocondensable, negative photocrosslinkable resin, emits light. The non-reacted portion that has not been irradiated is partially removed. In the case of a positive photodegradable resin, the light-irradiated decomposition-reacted portion is partially removed.
[0074]
After the photoreaction is performed, the remaining portion as a soluble portion is removed with various solvents. The removal solvent that can be used can be appropriately selected according to the solubility of the photoreactive resin to be used. For example, in the case of an aqueous emulsion type resin, water, an acidic aqueous solution, an alkaline aqueous solution can be used, Various organic solvents may be used.
[0075]
Next, as the process D, the photoreactive resin is partially removed, and the retroreflective article in which the specular reflection layer is exposed is partially made non-specular.
[0076]
As a means to make the exposed part of the specular reflection layer non-specular, the metal layer is oxidized, hydroxide, by means of metal oxide treatment, anodized film treatment, chromate film treatment, phosphate film treatment, etc. By changing to an inorganic salt compound such as chromate and phosphate and an organic salt compound such as oxalate, the surface becomes non-specular and the reflection performance is lost, and the portion is formed as an image.
[0077]
As the non-specular means that can be used in the present invention, metal oxide treatment of a specular reflection layer made of aluminum and aluminum alloys is preferable. Since aluminum is an amphoteric metal, various inorganic acids, organic acids, and alkalis can be used as an oxidizing agent.³⁺In the alkaline solution, the aluminate ion AlO₂ ⁻As a condition of the metal oxide film, it is important to carry out in a neutral region where the pH is 4 to 8 and to passivate, that is, to passivate.
[0078]
As the metal oxide film agent that can be used, aqueous solutions of acetic acid, hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, ammonium hydroxide, sodium carbonate, sodium hydroxide and the like are preferable. In particular, acetic acid, sodium silicate, and aqueous ammonia are preferable because a wide range of pH conditions can be adopted. The metal oxide film formed is believed to be a hydrate of aluminum oxide such as balite and boehmite.
[0079]
The above-described metal oxide treatment can also be employed for metals other than aluminum. In that case, it is necessary to select an acid and an alkali as appropriate in accordance with the properties of the metal to be used.
[0080]
Further, as a non-specularized means by metal oxide treatment that can be used in the present invention, boehmite treatment of a specular reflection layer made of aluminum and aluminum alloys by hot water treatment is preferable.
[0081]
Examples of the boehmite treatment include a method of heat-treating aluminum and an aluminum alloy in water. At this time, it is preferable to add ammonia or amines in water because a stable film can be formed.
[0082]
Further, as a method of inorganic chromate treatment of aluminum and aluminum alloy, non-mirror surface by so-called chemical conversion film such as chromate film treatment and phosphate film treatment can be used.
[0083]
As a method for the phosphoric acid treatment, a solution obtained by adding calcium phosphate to a zinc phosphate solution can be used to make it non-mirror-like by forming a phosphorylated film by an immersion method. Furthermore, a manganese phosphate-based film can also be employed.
[0084]
As a method of chromate treatment of aluminum and aluminum alloy, chromic acid film is obtained by treating with chromic acid and chromate as a main component with a treatment liquid containing fluoride, oxidant, chloride or phosphate. A so-called chromate film can be formed to make it non-mirror surface. Although it depends on the composition of the aluminum alloy and the composition of the treatment liquid to be used, the treatment can be carried out by dipping or spraying from room temperature to 70 ° C. for several seconds to 10 minutes.
[0085]
Further, as other means for making the aluminum and aluminum alloys non-specular which can be used in the present invention, anodized film treatment is preferable.
[0086]
The anodized film treatment in the present invention can be made non-specular by electrolytic treatment using a solution of sulfuric acid, oxalic acid, phosphoric acid, chromic acid or the like with the metal mirror reflection layer as an anode, so-called alumite. Specific methods for these treatment methods are described in the sulfuric acid anodizing technical standard defined in Japanese Industrial Standard JIS H9500 and the oxalic acid anodizing technical standard defined in JIS H9501, so here It is replaced with a concrete description by citation of
[0087]
In step D above, the alkali or acid used to partially non-specularize the photoreactive resin or specular reflection layer is washed with a neutralizing agent or water, and the adjacent specular reflection layer is cleaned. It is preferred that the remaining part is not violated.
[0088]
The remaining photoreactive resin layer may or may not be left as it is. In order to remove the photoreactive resin layer, it is possible to use a method such as removal using a stronger solvent or the like, or peeling off together with the photoreactive resin layer after laminating an adhesive sheet.
[0089]
In the present invention, the exposed portion of the specular reflection layer can be made non-specular on the spot, and then the non-specular portion can be colored by a coloring method involving impregnation with a dye or pigment or a secondary electrolytic coloring method. As a coloring method, a method of impregnating a colored resin containing various dyes or pigments, a secondary electrolytic coloring method, or the like can be employed.
[0090]
Further, the chromate salt, phosphate, and the like generated in step D may be distinguished from the specular reflection portion where the product itself is colored and does not form an image. Also in the boehmite processing, the color tone of the image can be changed from white to black by appropriately changing the processing conditions. Specific boehmite treatment conditions include treatment in hot water and aluminum to Al.₂O₃・ H₂O (Boehmite) can be used, but in order to suppress dissolution of aluminum, acids such as hydrogen fluoride, chromic acid, tartaric acid and phosphoric acid and alkali compounds such as chromate and phosphate are added as inhibitors. It is preferable to do this. Furthermore, the MBV method using chromate and sodium carbonate can also be employed. The resulting boehmite film can change the color tone of the image from white to black with these additives.
[0091]
Furthermore, as a coloring method by partially impregnating the non-mirror surface portion with a dye or pigment, various pigments or dyes can be sprayed or immersed. Dyes that can be used include various direct dyes (Congo Red, etc.), acidic dyes (Orange H, Rose Red, etc.), basic dyes (Malachite Green, Auramin, etc.), and mordants such as tannic acid, gallic acid, and phenol. It is preferable to use in combination with the above. Such a coloring method using a dye or pigment is particularly preferable in a non-mirror-finished portion in which aluminum is treated in Step D to be changed into an oxide or hydroxide.
[0092]
As a specific method for dyeing aluminum oxide, it is dyed in various colors such as black, ash, brown, yellow, red, blue using a mixture of various inorganic salts and organic dyes known per se. These dyed images are particularly preferred because of excellent visibility and weather resistance.
[0093]
As a method for dyeing aluminum oxide black, a method using an ammonium molybdate and an ammonium chloride aqueous solution, a method using an ammonium molybdate and an ammonium nitrate aqueous solution, or the like can be employed.
[0094]
As a method for dyeing aluminum oxide brown, a method using an aqueous solution of potassium sulfate, vanadium sulfate, potassium dichromate and alizarin dye, a method using an aqueous solution of potassium permanganate and manganese sulfate, or the like can be employed.
[0095]
Moreover, as a method of turning the aluminum oxide brown, a method using an aqueous solution of potassium sulfate and a morin dye can be employed.
[0096]
Further, in the case of a specular reflection layer formed of aluminum, it can be colored in black, dark ash, dark yellow, dark red, dark blue, or the like by a so-called secondary electrolytic coloring method. An image colored by this method is formed as a chemically stable image, and is therefore excellent in durability and weather resistance.
[0097]
As a method of coloring an image by the secondary electrolytic coloring method, after the specular reflective layer made of aluminum is so-called alumite by anodizing film treatment in Step D, subsequently, secondary electrolytic coloring is performed by a method known per se. it can.
[0098]
The retroreflective article on which the image formed as described above is formed can be laminated with an adhesive or a pressure-sensitive adhesive for the purpose of lamination on aluminum, iron, plastic, glass, paper, wood board or the like. As a method of laminating, it is possible to employ a method in which an adhesive liner obtained by laminating an adhesive and a release liner and a retroreflective article are pressure-bonded while applying heat with a pressure-bonding roll as necessary.
[0099]
As an adhesive that can be used for the retroreflective sheet of the present invention, a pressure-sensitive adhesive, a heat-sensitive adhesive, a cross-linkable adhesive, and the like can be appropriately selected. Pressure sensitive adhesives such as butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, nonyl acrylate and other acrylic esters and silicone resin adhesives obtained by copolymerizing acrylic esters with methacrylic acid, vinyl acetate, etc. An agent, a rubber adhesive, or the like can be used. As the heat sensitive adhesive, acrylic, polyester, epoxy resin, olefin resin and the like can be used.
[0100]
Next, the present invention will be described in more detail with reference to the drawings.
[0101]
FIG. 1 is a cross-sectional view illustrating an encapsulated retroreflective article based on the prior art. The printing layer 3 is installed by a printing method to form an image. The specular reflection layer 7 forms a retroreflective element placed on the minute glass sphere 5 through the focal layer 6 and is laminated on the flat and transparent surface layer 2 through the fixing layer. Further, an adhesive layer 8 and a release material layer 9 are installed in the specular reflection layer so that the incident light 1 is retroreflected in the light incident direction.
[0102]
Next, a method for forming an encapsulated retroreflective article on which an image is formed according to the present invention will be described in detail with reference to FIGS.
[0103]
FIG. 2 is a cross-sectional view of an encapsulated retroreflective article having no image formed by the prior art for use as a starting material used in the present invention. The first surface has a flat and transparent surface layer 2, and the retroreflective element in which the specular reflection layer 7 is placed on the minute glass bulb 5 through the focal layer 6 is exposed on the second surface.
[0104]
FIG. 3 is a diagram for explaining the process A in which the photoreactive resin 10 is laminated on the exposed specular reflection layer 7.
[0105]
FIG. 4 is a diagram for explaining a process B in which a light shielding mask 11 is placed on the laminated photoreactive resin 10 and selective light reaction is performed by irradiating light. The selective photoreaction can also be achieved by selectively irradiating light by a laser beam method without using a mask as shown in FIG.
[0106]
Fig. 5 shows the non-reaction in which the photoreactive portion formed by selective photoreaction was not irradiated with light in the case of a photopolymerizable and photocondensable negative photocrosslinkable resin using various solvents. It is a figure explaining the process C which removes the decomposition | disassembly reaction part irradiated with light partially in the case of positive type photodegradable resin. The photoreactive resin layer 10 has an image forming portion removed, and the specular reflection layer is exposed.
[0107]
FIG. 6 shows a retroreflective article in which an image is formed on a portion of the specular reflection layer 7 exposed in the step of FIG.
[0108]
FIG. 7 is a view in which an adhesive layer 8 is provided to attach the retroreflective article on which the image in FIG. 6 is formed to various base materials.
[0109]
FIG. 8 is a cross-sectional view illustrating a specular reflection type prism retroreflective article on which an image 3 is formed by a printing method based on the prior art. The first surface has a transparent and flat surface layer 2, the reflecting surface of the prism element in the prism layer 12 has a specular reflection layer 7, and an adhesive layer 8 and a release material layer 9 are provided.
[0110]
Next, a method of forming a specular reflection type prism retroreflective article on which an image is formed according to the present invention will be described in detail with reference to FIGS.
[0111]
FIG. 9 shows a process B in which a light-shielding mask 11 is installed on a prism-type retroreflective article in which a photoreactive resin 10 is installed on the specular reflection layer 7 (process A), and light is irradiated to perform a selective photoreaction. FIG. The selective photoreaction can also be achieved by selectively irradiating light by a laser beam method without using a mask as shown in FIG.
[0112]
FIG. 10 shows a non-reaction in which the photoreactive portion formed by selective photoreaction was not irradiated with light in the case of a photopolymerizable and photocondensable negative photocrosslinkable resin using various solvents. It is a figure explaining the process C which removes the decomposition | disassembly reaction part irradiated with light partially in the case of positive type photodegradable resin. The photoreactive resin layer 10 has an image forming portion removed, and the specular reflection layer is exposed.
[0113]
FIG. 11 shows a retroreflective article in which an image is formed on a portion of the specular reflection layer 7 exposed in the step of FIG.
[0114]
FIG. 12 is a diagram in which an adhesive layer 8 is installed to attach the retroreflective article on which the image in FIG. 11 is formed to various substrates.
[0115]
【The invention's effect】
[0116]
The image formed by the method according to the present invention is formed directly on the reflective element, and the image itself is a composition that is easily decomposed by the ingress of light, water, etc., such as a colorant by printing ink or an organic binder resin. Therefore, an image having excellent weather resistance and durability can be formed.
[0117]
In a method for forming an image by printing using a printing ink on the surface (first surface) or inner surface of the surface protective layer, which is a conventionally known method for forming an image, the resin layer is exposed to light from the outside. Deterioration is easily promoted by water intrusion, and it is difficult to obtain an image with excellent durability. However, in the image forming method by partial non-specularization of the specular reflection layer according to the present invention, the substance that forms the generated image is a chemically stable metal oxide or various metal salts. Since the problem of deterioration of printing ink used as an image cannot occur, an image having excellent durability is formed.
[0118]
Further, an adhesive layer is partially formed on the metal adhesion layer formed on the retroreflective microprism surface as disclosed in Martin's Japanese Patent Laid-Open No. 4-229244 and Japanese Patent Laid-Open No. 1-231004. In the method of forming a retroreflective microprism sheet that is not partially provided with a metal layer by peeling off the metal layer that is not protected by the adhesive layer, it is necessary to install the adhesive layer by printing or the like. There was a problem in that a clear image could not be formed due to the adhesive containing the solvent flowing out along the grooves in between. Furthermore, the prism tends to be deformed by the solvent and the retroreflective performance tends to deteriorate. However, in the method of forming an image by making the specular reflection layer partially non-specular in the present invention, a clear image can be formed without the above-mentioned problems.
[0119]
In addition, the laser image forming method has a problem in that the retroreflective performance is deteriorated due to partial destruction of the minute glass spheres and prisms which are reflective elements. Furthermore, because the diameter of the laser beam that can be used is small, an image that can be formed is obtained as an aggregate image of minute dots, so that it is difficult to obtain a clear image and it is difficult to form a wide range of images. In the method for forming an image by partially non-specularizing the specular reflection layer according to the present invention, it is possible to form a clear and wide-ranging image in which the above-described problems are unlikely to occur.
[0120]
Furthermore, in the present invention, the formed metal oxide or metal salt can be colored using various colorants. These colored layers do not require a binder of a necessary organic substance such as ink, and are excellent in durability. In the present invention, after the exposed portion of the specular reflection layer is made non-specular on the spot, the non-specular portion can be colored by a coloring method by impregnation with a dye or pigment or a secondary electrolytic coloring method. Therefore, it is possible to form a chemically stable colored image.
[0121]
Furthermore, in retroreflective articles in which contactless IC communication devices with thin-layer antennas are stacked, if a metal film such as aluminum, aluminum-magnesium alloy, aluminum-manganese alloy, silver, or nickel is installed, There arises a problem that communication is hindered by reflection. However, when the specular reflection layer according to the present invention is partially made non-specular, the information communication installed on the lower surface of the reflection element layer so as not to be obstructed by the reflection of radio waves by eliminating the conductivity of the specular reflection layer. It is optimal for improving the reception sensitivity of a thin-layer antenna.
[0122]
Hereinafter, the present invention will be described more specifically with reference to examples.
【Example】
[0123]
<Example 1>
Specular reflection prism type retroreflective sheet manufactured by Nippon Carbide Industries Co., Ltd., a retroreflective sheet having a second surface where the specular reflection layer is exposed before the adhesive layer of the Nikkalite crystal grade # 96502 type is installed. As a starting material (starting material 1), a retroreflective sheet having an image formed by the following steps was prepared. Below, this manufacturing process is demonstrated in detail.
[0124]
The starting material 1 used in this example has a structure without the printing layer 3, the pressure-sensitive adhesive layer 8 and the release material layer 9 of the conventionally known specular reflection type prism-type retroreflective sheet shown in FIG. Is a surface layer 2 made of acrylic resin having a flat and transparent thickness of 50 μm, and a mirror reflecting layer 7 made of aluminum having a thickness of 0.8 μm is formed on the reflecting surface of the prism element 12 made of polycarbonate by vacuum deposition. Is installed and exposed.
[0125]
As the photoreactive resin, a dry film photoresist type alkali development type photosensitive film “Photec” H2300 manufactured by Hitachi Chemical Co., Ltd. was used. This dry film resist had a film thickness of 48 μm and was protected on both sides by a light-transmitting carrier film and a protective film.
[0126]
Using a pair of thermocompression-bonding rolls, the starting material 1 is laminated so that no air remains on the exposed surface of the specular reflection layer while peeling off the protective film of the dry film resist on the starting material 1, A process product 1A in which a dry film resist and a carrier film were laminated was obtained.
[0127]
A high-pressure mercury lamp type UV irradiation device with a lamp input of 80 w / cm is installed on the surface of the carrier film side of this processed product 1A by installing a 75 μm thick polyester resin mask film printed with black ink. (Product made by USHIO INC.) Was subjected to an exposure treatment for 20 seconds to obtain a process product 1B in which the photoreactive resin was partially reacted by selective light irradiation. The mask film used was printed with alphabet letters “ABC” having a character size of 11 points and a character of “Century” for the purpose of evaluating visibility.
[0128]
Next, after removing the carrier film of the above-mentioned process product 1-2, a 10% sodium carbonate aqueous solution whose pH is adjusted to 8 is used as a developing solution, and the photoreactive resin of the unreacted part at a temperature of 60 ° C. After removing the film, the product was washed with water to produce a process product 1C in which the mirror layer was partially exposed.
[0129]
Subsequently, the above-mentioned processed product 1C was oxidized in a 10% aqueous sodium carbonate solution adjusted to a pH of 8 at a temperature of 60 ° C., and the partially exposed aluminum specular reflection layer was made non-specular. To form a process product 1D.
[0130]
A 50 μm thick adhesive made of acrylic resin (Nisset KP1818 manufactured by Nippon Carbide Industries Co., Ltd.) and a 80 μm thick polypropylene manufactured by Okura Industries Co., Ltd. A retroreflective sheet (Prototype 1) on which an image was formed was prepared by laminating these release materials.
[0131]
<Example 2>
Using the processed product 1C prepared in Example 1, the exposed mirror surface layer was made non-specular by subjecting the exposed mirror surface layer to a non-mirror surface under the condition of a temperature of 70 ° C. using the following chromate treatment liquid, thereby producing a processed product 2D.
<Chromate treatment solution>
2% sodium carbonate
0.2% acid sodium phosphate
2% potassium dichromate
2% potassium permanganate
[0132]
Further, the processed product 2D is coated with an acrylic resin adhesive (Nissetsu KP1818 manufactured by Nippon Carbide Industries Co., Ltd.) having a thickness of 50 μm and an Okura having a thickness of 80 μm on the second surface where the image is formed in the same manner as in Example 1. A retroreflective sheet (Prototype 2) on which an image was formed by laminating a release material made of polypropylene manufactured by Kogyo Co., Ltd. was produced.
[0133]
<Example 3>
Using the process product 1C created in Example 1, as a process 3C, hydrothermal treatment was performed in pure water at a temperature of 95 ° C., and the exposed mirror surface layer was made non-mirror surface by boehmite treatment to produce a process product 3D. .
[0134]
Further, the processed product 3D was coated with an acrylic resin adhesive (Nissetsu KP1818 manufactured by Nippon Carbide Industries Co., Ltd.) having a thickness of 50 μm and an Okura having a thickness of 80 μm on the second surface on the image-formed side as in Example 1. A retroreflective sheet (Prototype 3) on which an image was formed was prepared by laminating a polypropylene release material manufactured by Kogyo Co., Ltd.
[0135]
<Example 4>
Using the processed product 1D created in Example 2, the non-mirrored portion was dyed. As a method of dyeing, 1 liter of pure water is immersed in a dyeing solution in which 25 g of potassium sulfate, 0.5 g of vanadium sulfate, 0.5 g of potassium dichromate, and 1 g of alizarin dye are dissolved. Staining was performed.
[0136]
<Example 5>
In place of the starting material 1 used in Example 1, the specular reflective layer is exposed before the encapsulated lens type retroreflective sheet manufactured by Nippon Carbide Industries Co., Ltd., and the Nikkalite SEG type adhesive layer is exposed. A retroreflective sheet (prototype 5) on which an image was formed was produced in the same manner as in Example 1 except that a retroreflective sheet having a surface was used as a starting material (starting material 5).
[0137]
The starting material 5 used in Example 5 has a structure without the conventionally known encapsulated lens type retroreflective sheet shown in FIG. 1, the Nikkalite SEG type printing layer 3, the adhesive layer 8, and the release material layer 9. As shown in FIG. 2, the first surface is a flat and transparent surface layer 2 made of acrylic resin having a thickness of 45 μm, and a mirror reflection layer 7 made of aluminum having a thickness of 1 μm is vacuum-deposited on the minute glass sphere 5. It is installed and exposed by law.
[0138]
<Example 6>
Positive g-line resist resin manufactured by Tokyo Ohka Kogyo Co., Ltd. instead of the dry film resist film used to prepare the process product 5A described in Example 5 using the starting material 5 used in Example 5. Using OFPR800, a thickness of 40 g / m is obtained by performing a drying process after laminating on the entire second surface where the specular reflection layer is exposed by screen printing.²A retroreflective sheet (prototype 6) on which an image was formed in the same manner as in Example 5 was obtained except that the photoreactive resin layer was installed.
[0139]
It is believed that the resist resin used in Example 6 is composed of a novolac resin binder using a naphthoquinone diazide (NQD) compound as a dissolution inhibitor. The ultraviolet ray used for the exposure was an ultraviolet ray having a wavelength of 365 nm. Further, using an aqueous solution of sodium carbonate having a pH of 8 and a concentration of 15% by weight as an exposure solution, after removing the unreacted portion of the resist resin at a temperature of 60 ° C., washing with water is performed to produce a process product 6C. Went.
[0140]
Subsequently, the above-described processed product 6C was oxidized in a 15% aqueous sodium carbonate solution adjusted to a pH of 8 at a temperature of 60 ° C., and the partially exposed aluminum specular reflection layer was made non-specular. To form a process product 6D.
[0141]
Further, the non-mirror surface portion was dyed by the same method as in Example 4. As a method of dyeing, 1 liter of pure water is immersed in a dyeing solution in which 25 g of potassium sulfate, 0.5 g of vanadium sulfate, 0.5 g of potassium dichromate, and 1 g of alizarin dye are dissolved. Staining was performed.
[0142]
After the process product 6D is dyed, a 50 μm thick acrylic resin adhesive (Nisset KP1818 manufactured by Nippon Carbide Industries Co., Ltd.) and an 80 μm thick Okura Industrial Co. A retroreflective sheet (Prototype 6) on which an image was formed was prepared by laminating manufactured release materials.
[0143]
<Comparative example>
As a comparative product, instead of the starting material 1 used in Example 1, an encapsulated lens type retroreflective sheet manufactured by Nippon Carbide Industries Co., Ltd., and a retroreflective sheet having a printed image formed on the Nikkalite SEG type were used. In the retroreflective sheet used in the comparative example, a red printing layer 3 is installed in a gravure printing manner on the conventionally known encapsulated lens type retroreflective sheet shown in FIG. As shown in FIG. 2, the first surface is a flat and transparent surface layer 2 made of acrylic resin having a thickness of 45 μm, and a mirror reflection layer 7 made of aluminum having a thickness of 1 μm is vacuum-deposited on the minute glass sphere 5. It is installed and exposed by law.
[0144]
<Measurement method 1> Visibility test
Visibility of the image formed on the condition that the prototype with the character image “ABC” is placed horizontally, irradiated with fluorescent light from directly above the height of 1 m, and the observation angle is 45 degrees and the distance is 45 cm. Was evaluated visually and evaluated as follows.
A: The presence of the image “ABC” can be clearly confirmed.
B: The presence of the image “ABC” can be confirmed.
C: The presence of the image “ABC” can be faintly confirmed.
D: Presence of the image “ABC” cannot be confirmed.
[0145]
<Measuring method 2> Visibility after weather resistance test
A weather resistance test was performed according to JIS Z-9117, except that CXW-B-82501500 manufactured by Atlas Electric Device Co., Ltd. was used as a weather resistance tester and the exposure time was 3000 hours. The visibility of the image after the accelerated weather resistance test was evaluated based on the visibility test method defined in Measurement Method 1.
[0146]
<Measurement method 3> Measurement of retroreflective performance before weather resistance
The retroreflective performance measuring instrument “Model 920” manufactured by Advanced Retro Technology was used, and the retroreflective performance of a 100 mm × 100 mm prototype before the accelerated weathering resistance test was observed in accordance with JIS Z-9117. Measurement was made at 5 points at 2 ° and an incident angle of 5 °, and the average value was taken as the retroreflective performance of the retroreflective sheet.
[0147]
<Measurement method 4> Measurement of retroreflection performance after weather resistance
As with measurement method 3, the retroreflective performance measuring instrument “Model 920” manufactured by Advanced Retro Technology was used, and the retroreflective performance of the 100 mm × 100 mm prototype after the accelerated weather resistance test was in accordance with JIS Z-9117. Measured at appropriate five points with an observation angle of 0.2 ° and an incident angle of 5 °, and the average value was taken as the retroreflective performance after the accelerated weather resistance evaluation of the retroreflective sheet.
[0148]
<Measuring method 5> Analysis of metal components after non-specularization treatment
In order to confirm that the mirror layer metal remained in situ after the non-specular treatment and an image was formed, the metal component of the image forming portion was analyzed by the SEM-EDS method. The analyzer used for the measurement was a JSM-5900 type analyzer manufactured by JEOL Ltd., and the presence of aluminum was confirmed with a signal intensity at a voltage of 1.5 keV.
[0149]
Table 1 in which the prototypes described in the above examples are compared by the above measurement method is shown below.
[0150]
[Table 1]

[0151]
Further, the following image portion of the sample was analyzed by EPMA analysis to confirm that the mirror layer metal remained in situ after the non-specular treatment and an image was formed.
Analysis sample 1: Specular reflection layer of starting material 1 used in Example 1
Analysis sample 2: Sample obtained by etching sample 1 with sodium hydroxide to remove the aluminum layer.
Analytical sample 3: Image forming part of prototype 1 prepared in Example 1
[0152]
The analysis results of analysis samples 1 to 3 are shown in FIGS. Analytical sample 1 contains aluminum and covers the reflective element, but analytical sample 2 etched with 1N-sodium hydroxide aqueous solution does not contain aluminum, and the reflective element is exposed at the image portion. Show. On the other hand, in the analytical sample 3 on which an image is formed by the method of the present invention, it can be visually confirmed that the image forming portion is non-specular. However, aluminum remains and is non-specular on the spot. It shows that.
[0153]
Although each of prototypes 1 to 6 on which an image was formed according to the description of the present invention showed excellent visibility and durability, the printed image used in the comparative example was particularly inferior in durability.
[Brief description of the drawings]
FIG. 1 Enclosed retroreflective article according to the prior art
FIG. 2 is a view for explaining the process of the encapsulated retroreflective article of the present invention.
FIG. 3 is a diagram for explaining the process of the encapsulated retroreflective article of the present invention.
FIG. 4 is a diagram for explaining a process of an encapsulated retroreflective article according to the present invention.
FIG. 5 is a diagram for explaining the process of the encapsulated retroreflective article of the present invention.
FIG. 6 is a diagram for explaining the process of the encapsulated retroreflective article of the present invention.
FIG. 7 is a view for explaining the process of the encapsulated retroreflective article of the present invention.
FIG. 8 is a conventional specular reflection type prism type retroreflective article.
FIG. 9 is a diagram for explaining the process of the prism type retroreflective article of the present invention.
FIG. 10 is a diagram for explaining a process of the prism type retroreflective article of the present invention.
FIG. 11 is a diagram for explaining a process of the prism type retroreflective article of the present invention.
FIG. 12 is a diagram for explaining the process of the prism type retroreflective article of the present invention.
FIG. 13 shows the metal analysis result of analysis sample 1.
FIG. 14 shows the result of metal analysis of analysis sample 2
FIG. 15 shows the metal analysis result of analysis sample 3.
[Explanation of symbols]
1 Incident light
2 Surface layer
3 Print layer (image)
4 Adhesive layer
5 Minute glass bulb
6 Focus layer
7 Specular reflection layer
8 Adhesive layer
9 Release material layer
10 Photoreactive resin layer
11 Light shielding mask
12 Prism layer
13 Non-mirror surface

Claims (17)

A recursion comprising a first layer comprising a substantially transparent layer having a flat first surface and a second layer comprising a retroreflective element layer having a second surface with the specular reflection layer exposed. A. A step of installing a photoreactive resin layer on the specular reflection layer on the second surface using a reflective article B. A step of partially reacting the photoreactive resin with selective light irradiation C. Photoreactivity A step of partially removing a selected region of the resin layer. D. A retroreflective article on which an image is formed by a step of forming an image by making the exposed portion of the specular reflection layer non-specular on the spot. The material constituting the specular reflection layer is a metal film selected from aluminum, aluminum-magnesium alloy, aluminum-manganese alloy, silver, copper, and nickel, and the means for making the exposed portion of the specular reflection layer non-specular is a metal oxide treatment A retroreflective article having an image formed thereon according to claim 1, which is an anodized film treatment, a chromate film treatment, or a phosphate film treatment. 3. The image is formed by coloring the non-specularized portion by coloring with a dye or pigment or secondary electrolytic coloring after the exposed portion of the specular reflection layer is made non-specular in situ. The retroreflective article as described. The retroreflective element on which the image according to claim 1 is formed, wherein the retroreflective element layer is composed of a retroreflective element selected from the group of an encapsulated lens type, a capsule lens type, and a specular reflection type prism type retroreflective element. Sex goods. A retroreflective element constituting a specular reflection type prism type retroreflective element is a pair of triangular pyramid cube corner type retroreflective elements formed by cutting a cross section intersecting from three directions by a substantially symmetrical parallel V groove group. A retroreflective article on which the image according to claim 1 is formed. A retroreflective element constituting a specular reflection type prism type retroreflective element is a pair of triangular pyramid cube corner type retroreflective elements formed by cutting a cross section intersecting from three directions by a substantially symmetrical parallel V groove group. 6. The retroreflective article having an image formed thereon according to claim 5, wherein the depth of at least one of the three-direction V grooves is different from the depth of the other two-direction V grooves. The image according to any one of claims 1 to 6, wherein the photoreactive resin layer placed on the second-surface specular reflection layer is one of photopolymerizable, photocondensable, photocrosslinkable and photodegradable. A retroreflective article formed. The photoreactive resin layer placed on the second mirror reflection layer is one of photopolymerizable, photocondensable, photocrosslinkable, and photodegradable. The retroreflective article in which the image in any one of Claims 1-7 was formed is 10-200 micrometers in thickness. The retroreflective article in which the image in any one of Claims 1-8 formed in the sheet form form is provided with the photoreactive resin layer installed on the mirror-reflection layer of the 2nd surface. The retroreflective article on which an image according to any one of claims 1 to 9 is formed, wherein the method of selectively irradiating light is a light shielding mask method or a light scanning method. Using a retroreflective article comprising a first layer having a flat first surface and a second layer comprising a retroreflective element layer having a second surface with the specular reflection layer exposed, A.2 Step B. Placing the photoreactive resin layer on the specular reflection layer on the surface B. Partially reacting the photoreactive resin with selective light irradiation C. Partially removing the selected region of the photoreactive resin layer Step D. A method of forming an image by a step of forming an image by making the exposed part of the specular reflection layer non-specular in situ. The material constituting the specular reflection layer is a metal film selected from aluminum, aluminum-magnesium alloy, aluminum-manganese alloy, silver, copper, and nickel, and the means for making the exposed portion of the specular reflection layer non-specular is a metal oxide treatment The method for forming an image according to claim 11, which is an anodized film treatment, a chromate film treatment, or a phosphate film treatment. 13. The image is formed by coloring the non-specularized portion by a coloring method using a dye or a pigment or a secondary electrolytic coloring method after the exposed portion of the specular reflection layer is made non-specular in situ. A method of forming an image. The method for forming an image according to claim 11, wherein the photoreactive resin layer placed on the second-surface specular reflection layer is any of photopolymerizable, photocondensable, photocrosslinkable and photodegradable. . The photoreactive resin layer placed on the second mirror reflection layer is one of photopolymerizable, photocondensable, photocrosslinkable, and photodegradable. The method for forming an image according to claim 11, wherein the thickness is 10 to 200 μm. The image in any one of Claims 11-15 in which the photoreactive resin layer installed on the mirror reflective layer of a 2nd surface is supplied with a sheet-like form, and is installed on the mirror reflective layer of a 2nd surface. How to form. The method for forming an image according to claim 11, wherein the method of selectively irradiating light is a light shielding mask method or a light scanning method.

Images