JPH043901B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a technology for displaying a label on an article having a surface-cured film, which cannot be detected under sunlight or indoor light, but can be confirmed by coloring when irradiated with ultraviolet light. [Prior Art] Currently, various surface hardening treatments are being carried out for the purpose of improving the surface hardness of plastics made of diethylene glycol bisallyl carbonate polymer, polycarbonate, and the like. However, some products have poor scratch prevention effects and are often returned as complaints by consumers. In order to respond appropriately to such complaints, it is not only necessary to be able to confirm that the product is manufactured by one's own company, but it is also preferable that the product has a structure that cannot be identified by the consumer. A specific method of such a detection means is adding a hidden mark. In other words, the label cannot be detected under sunlight or indoor light, and the label is confirmed by developing a color when irradiated with ultraviolet light.However, conventionally known methods involve using a fluorescent dye in a solid sublimable inert diluent and a liquid carrier substance. A method has been proposed in which a marker rubber stamp or the like is printed using an ink prepared by mixing the ink, and the ink is penetrated and incorporated by heat treatment (for example, JP-A-56-28886 and JP-A-54-112657). On the other hand, Japanese Patent Application Laid-open No. 17101/1983 discloses a technique in which a marker is printed using a fluorescent dye that is kneaded with water to form a paste, and a hidden mark is added by heat treatment. (Problem to be solved by the invention) These markings cannot be seen under normal use under sunlight or indoor light, but when irradiated with ultraviolet rays, they develop a color and can be confirmed. This is used for warranty purposes, but when observed under a laser beam, which is an effective means of inspecting the lens surface in detail and inspecting its optical properties,
In the prior art display method, traces of printing are recognized. This is because a slight refractive error occurs in the printed portion of the sign, which is not preferable as an optical lens such as a spectacle lens. Furthermore, the technique disclosed in JP-A-61-17101 has problems such as the amount of water used for kneading changing over time, resulting in variations in the sharpness of hidden marks. [Means for Solving the Problems] An object of the present invention is to provide an article having a surface-cured film that can be dyed or dyed through, and which cannot be detected under normal usage conditions under sunlight or indoor light, and which is irradiated with ultraviolet rays. The object of the present invention is to provide a method for displaying a label, which can be confirmed by color development and which causes no optical problems when observing the printed part with a laser beam. Still another object of the present invention is to provide a technique for adding hidden marks that achieve the above-mentioned purposes with good reproducibility, can be permanently used, and are highly productive. That is, the present invention is characterized in that a label is printed on the surface of an article having a hardened surface film that is dyeable or dye permeable using a mixed powder consisting of a fluorescent dye and a non-fluorescent solid substance, and then dyed. This is about hidden marks. In the present invention, many known film compositions can be applied to the surface hardened film capable of dyeing or dye permeation. In particular, an organopolysiloxane-based hardened surface film is preferably used because it has a high surface hardness and is dyeable or dye permeable. Specific examples of such organopolysiloxane surface hardening films include Japanese Patent Publication No. 60-11727.
Examples include techniques listed in Japanese Patent Publication No. 57-2735. Materials used as base materials for articles on which surface hardening films are provided include inorganic glass, ceramics, inorganic products such as metals such as iron plates, as well as polymethyl methacrylate and its copolymers, polycarbonate, polystyrene, polyacrylonitrile, and polychloride. Thermoplastic plastics represented by vinyl, cellulose, polyethylene, polyester, etc., diethylene glycol bisallyl carbonate polymer (CR-39 polymer), polyfunctional (meth)acrylate polymer and its copolymer, divinylbenzene polymer and It can also be applied to thermosetting plastics such as copolymers, polyurethane, and epoxy resins, as well as paper, cardboard, and wood. In particular, plastic is particularly preferred from the viewpoints of surface hardening, transparency, lightness, impact resistance, and the like. On the other hand, the shape of the article may be any shape as long as it requires the present invention, but eyeglass lenses and sunglass lenses are particularly preferable because appearance quality is important. Furthermore, plastic cleansing, which is a high value-added product, has a particularly strong need for it, and is an article to which it is preferably applied. Next, the fluorescent dye referred to in the present invention is not particularly limited as long as it emits fluorescence when irradiated with ultraviolet rays, but it is preferably substantially colorless for the purpose of hiding marks. Many such fluorescent dyes are already commercially available, and some of them are particularly popular in terms of dyeing speed, fluorescence, etc.
Mikawhite ATN conc bulk powder (manufactured by Nippon Kayaku),
Kayalight A (manufactured by Nippon Kayaku), Mitsui oil-soluble fluorescent dye (manufactured by Mitsui Toatsu Chemical), and the like are preferably used. On the other hand, the non-fluorescent solid substance used in combination with these fluorescent dyes may be anything as long as it can be powdered, does not deteriorate the surface-cured film, and can be easily mixed with the fluorescent dye into a powder. However, in terms of stability, cost, ease of powderization, etc., it is preferable to use inorganic compounds. Specific examples of such inorganic compounds include various alkali metal salts such as sodium halide, potassium halide, lithium halide, sodium carbonate, potassium carbonate, various alkaline earth metal salts, silicon dioxide fine powder,
There are many things that can be mentioned. Among these inorganic compounds, those having no hygroscopic or deliquescent properties are particularly suitable for the present invention. Incidentally, surfactants and various solvents may be added to the mixed powder as long as it does not change the appearance, dyeability, or other properties, but if you take into account the removal of excess powder after printing, It is preferably in powder form. The mixing ratio of the fluorescent dye and the non-fluorescent solid should be determined depending on the type of fluorescent dye, the composition of the surface cured film, the required fluorescent color density, etc., but in general, it is 1 part by weight of the fluorescent dye. In contrast, non-fluorescent solids
100 to 0.1 part by weight is preferred. Various known methods can be used to mix the fluorescent dye and non-fluorescent solid material in the present invention. In addition, the particle size of the powder should be optimized depending on the content, size, and shape of the product, etc., but the primary particle size is The diameter is preferably 500 microns or less. The method of printing fluorescent dye on the surface of the article is not particularly limited, but the mixed powder prepared as described above is placed on a rubber stamp with a label engraved on it, excess powder is removed, and then the article with a surface hardening film is printed. A method of transfer printing on top is preferred. Next, in the present invention, it is necessary to fix the fluorescent dye to the article, and a dyeing treatment is performed. Here, the dyeing treatment refers to a treatment for transferring printed fluorescent dye to an article having a surface hardening film. This dyeing process is simple;
Also, heat treatment is preferable from the viewpoint of effectiveness. Heat treatment conditions vary depending on the type of powder, atmospheric humidity, surface hardening film composition, etc., and should be determined experimentally, but are usually 50 to 150°C for 5 minutes or more.
Enough hidden marks can be obtained by heating for 20 hours. The signs referred to in the present invention are kanji, hiragana, katakana,
Alphabetical letters, numbers, symbols, marks, etc.
It consists of a picture or a combination of these, etc.
Although not particularly limited, it is preferable to print clearly. In a preferred embodiment of the present invention, a surface hardening film is coated on an article substrate to make it printable, and then a label is engraved with a mixed powder consisting of a fluorescent dye and a non-fluorescent solid material, and then heat-treated. Therefore, there is a method in which the dyeing treatment and the hardening of the surface-cured film are simultaneously achieved. After the dyeing treatment, it is preferable from the viewpoint of commercial value to wind up the mixed powder remaining on the surface of the article with cloth, paper, or the like. Items created using this process are no different from unprinted items under normal usage conditions under sunlight or indoor light, but when exposed to ultraviolet light such as blacklight, the product develops color and the label becomes visible. can. Further, the obtained label will not disappear even if the surface of the article is wiped with water or an organic solvent, and will not disappear even if the article is subjected to post-processing such as dyeing or anti-reflection treatment. Next, the present invention will be explained by examples. Examples 1 to 4, Comparative Examples 1 to 2 (1) Preparation of coating composition for surface cured film (a) Co-hydrolysis of γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropylmethyldiethoxysilane Preparation of 42.4 parts of γ-glycidoxypropyltrimethoxysilane and γ-
99.7 parts of glycidoxypropylmethyldiethoxysilane was charged, and while stirring using a magnetic stirrer, 24.2 parts of a 0.05N hydrochloric acid aqueous solution was added dropwise while maintaining the liquid temperature at 10°C.
After the dropwise addition was completed, stirring was continued for another 30 minutes to obtain a hydrolyzate. (b) Preparation of coating composition 199.6 parts of isopropyl alcohol, 11.9 parts of acetylacetone,
Add and mix 1.6 parts of silicone surfactant,
After adding 338.3 parts of isopropyl alcohol-dispersed silica sol (average particle size 10 to 15 nm) and 6.45 parts of aluminum acetylacetonate and stirring thoroughly, a coating composition was obtained. (2) Preparation of surface-cured film article Using a -6.00 diopter lens of CR-39 (diethylene glycol bisallyl carbonate polymer) as a transparent base material, the coating composition prepared in (b) above was pulled up at a pulling speed of 10 cm/min. A surface cured film article was obtained which was dip coated under the following conditions and then precured at 82° C. for 12 minutes. (3) Preparation of mixed powder for hidden marks Fluorescent dye (Nippon Kayaku Mikawhite ATN
Conc bulk powder) and potassium bromide were mixed in the proportions shown in Table 1, and each was sufficiently pulverized and mixed in a mortar to obtain a mixed powder for hidden marks. (4) Preparation of Hidden Mark The mixed powder prepared in (3) was stamped on the surface-cured film article obtained in (2) above using a rubber stamp labeled with a TR stamp. After dyeing at 100° C. for 4 hours, excess mixed powder was removed with a cloth to obtain a plastic lens with hidden marks. (5) Evaluation method and results The lens obtained in (4) above was evaluated by the method shown below. The results are shown in Table 1. (a) Hidden mark performance We examined whether the TR mark printed under an ultraviolet lamp (black light) could be confirmed by color development. (b) Dyeing test 10% with disperse dye consisting of three primary colors: red, blue, and yellow.
The dyed product was dyed at 93°C for 1 minute, and the dyed product was examined for uneven dyeing.

[Table] [Effects of the Invention] The hidden mark obtained by the present invention has the following effects. The markings can be clearly seen using an ultraviolet lamp, making it easy to identify the manufacturer and provide appropriate services to consumers. When the UV lamp is removed, the symbol quickly disappears and maintains a high-quality appearance. Even if you dye from above the hidden marks, uneven dyeing will not occur. In addition, it does not affect post-processing such as anti-reflection processing and maintains hidden mark performance.

Claims (1)

[Claims] 1. A mark is printed on the surface of an article having a hardened surface film capable of dyeing or dye permeation using a mixed powder consisting of a fluorescent dye and a non-fluorescent solid substance, and is dyed. Features a hidden mark. 2. The hidden mark according to claim 1, wherein the surface cured film capable of being dyed or dyed is an organopolysiloxane cured film. 3. The hidden mark according to claim 1, wherein the fluorescent dye is substantially colorless. 4. The hidden mark according to claim 1, wherein the non-fluorescent solid substance is an inorganic compound. 5. The hidden mark according to claim 1, wherein the dyeing treatment is heat treatment. 6. The hidden mark according to claim 1, wherein the article is made of a plastic substrate. 7. The hidden mark according to claim 6, wherein the plastic substrate of the article is a plastic lens.