JP2006159794A - Decorative molded body having gradation design and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a gradation design which has a large shading difference between the darkest and lightest portions and a gradation being fine and varying in tones smoothly and is also interesting and impactful, regarding a decorative molded body decorated with a color design. <P>SOLUTION: The gradation design formed of a laminate of a diffusion layer 14 diffusing transmitted light, a halftone printed layer 15 forming a dot pattern and a ground layer 16 colored differently from the halftone printed layer 15 is formed on the molded body 13. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, a molded body represented by a key top for a push button switch (hereinafter referred to as “key top”) or a key sheet used in various electronic devices such as a mobile phone, a portable information terminal, and an AV device has a color design. More particularly, the present invention relates to a decorative molded body having a gradation design.

  Various designs have been given to decorative molded bodies such as key tops used in mobile phones and other information processing terminals due to intensifying design competition, and gradation design is also attracting attention as one of them.

  Usually, a method for obtaining a gradation design includes a method of changing the dot density and the size of each dot. For this gradation forming method, means for devising the formation of the dot pattern, such as solving the problem of the collapse of the dot pattern, is disclosed in Japanese Patent Laid-Open No. 2003-66586 (Patent Document 1) and the like. Improvements in precision and dot reproducibility are achieved. However, if this method is simply applied to a compact that has a small area such as a key top and is illuminated, there is a problem that the dot pattern is recognized and a fine gradation design cannot be obtained.

Therefore, as another method of applying a gradation design to the molded product, inks with different hues are printed in multiple times to obtain gradations with different hues, and the number and place of repeated printing using inks with the same hue. The method of obtaining gradation by changing has been studied. However, the former method has a problem that skill is required to finely adjust and change the hue. In the latter method, there is a problem that it takes time and labor to perform overprinting and that the difference in density between the darkest part and the thinnest part is small. In addition, quality is likely to vary depending on printing conditions, ink type, and other external factors, resulting in poor reproducibility. Therefore, it is not easy to obtain a decorative molded body having a gradation design, and the manufacturing cost is high. Also, by any of these methods, the resulting design is only a simple gradation, lacking in interest and having a low impact.
JP 2003-66586 A

  The present invention has been made to solve these problems, can increase the difference in density between the darkest part and the thinnest part, has a gradation that changes in tone smoothly and finely, The object is to obtain a decorative molded body that forms a gradation design with interest and impact and a method for producing the same.

  That is, the present invention relates to a decorative molded body in which the molded body is decorated with a color design, and the diffusion layer for diffusing transmitted light, the halftone printing layer for forming a dot pattern, and the halftone printing layer have different colors. Provided is a decorative molded body having a gradation design formed by laminating a colored base layer on the molded body.

  The molded body has a gradation design formed by laminating a diffusion layer for diffusing transmitted light, a halftone printing layer for forming a dot pattern, and a base layer colored differently from the halftone printing layer. Therefore, a gradation in which the dot pattern is not recognized can be obtained by the diffusion layer blurring the outline of the dot pattern. In addition, a gradation in which the halftone print layer forming the dot pattern has a large difference in density between a dark portion and a thin portion, and a gradation in which the tone is smoothly changed in a fine and adjacent portion is realized. Furthermore, since the underlayer is colored differently from the halftone print layer, it becomes a decorative molded body having a gradation design with interest and impact.

  More specifically, by making the chromatic colors of the halftone print layer and the undercoat layer different from each other, a gradation is formed with the color applied to the dot pattern forming the halftone print layer, and the undercoat layer is applied to the undercoat layer. A gradation can be formed even with the selected color.

  As for the hues of the halftone print layer and the underlayer, either the halftone print layer or the underlayer can be white. If either one is white, the gradation of the other color will be more prominent, and a gradation design that appears to form a monochrome gradation can be obtained.

  Further, at least one of the halftone print layer and the underlayer can be a metal color. If the halftone printing layer or the underlayer is made of a metallic color, a decorative molded body having gradations with different brightness and saturation can be obtained.

  The halftone printing layer is formed of screen printing ink, and can be a layer containing 0.1 wt% to 5.0 wt% of inorganic fine particles. Since the halftone printing layer is formed with screen printing ink and contains 0.1 to 5.0 wt% of inorganic fine particles, there is no dripping of the ink when the halftone printing layer is printed, and the formed dots spread. Hateful. Therefore, it becomes a halftone printing layer composed of dots having a large thickness and a small spread. As a result, the contrast between the dark portion and the light portion is large, and the gradation transition can be fine and fine and smooth gradation can be formed.

  Such a molded body can be a key top for a push button switch. If a key top for a pushbutton switch is used, it is possible to obtain a key top having a good design and high hobby.

  Furthermore, the present invention relates to a method for producing a decorative molded body in which a molded body is decorated with a color design, and a diffusion layer for diffusing transmitted light is provided on the molded body having translucency, and then dots are formed by screen printing. Provided is a method for producing a decorative molded body having a gradation design, characterized in that a halftone print layer for forming a pattern is provided, and then a base layer different in color from the halftone print layer is provided.

  A molded article having translucency is provided with a diffusion layer for diffusing transmitted light, then provided with a halftone printing layer for forming a dot pattern by screen printing, and then a base layer having a different color from the halftone printing layer Because of the gradation design provided, the difference between the darkest part and the thinnest part is large, and it has an excellent gradation that changes its color tone finely and smoothly. Can be manufactured. And the decorative molded object which can visually recognize a gradation design through a molded object can be obtained.

  Further, the present invention relates to a method for producing a decorative molded body in which the molded body is decorated with a color design, and a base layer is provided on the molded body, and then a dot pattern having a color different from that of the base layer is formed by screen printing. Provided is a method for producing a decorative molded body having a gradation design, characterized in that a halftone printing layer is provided and then a diffusion layer for diffusing transmitted light is provided.

  Because the molded body was provided with a base layer, then a halftone print layer that formed a dot pattern of a different color from the base layer by screen printing, and then a diffusion layer that diffused the transmitted light, and a gradation design was applied. It is possible to easily produce a decorative molded body having an excellent fine, smooth gradation and having an interesting and impactful effect. And even if it uses a molded object with poor transparency, the decorative molded object which has the outstanding gradation design can be obtained.

  Screen printing ink containing 0.1 wt% to 5.0 wt% of inorganic fine particles in the solid content can be used for printing of the halftone printing layer. Since the screen printing ink containing 0.1 to 5.0 wt% of inorganic fine particles in the solid content is used, there is no sagging of the ink when the halftone printing layer is printed, and printing with less bleeding can be performed. For this reason, it is possible to form dots that are thick and have little spread, and that appear to be fine and smoothly appear as if the density of adjacent areas changes.

  The molded body is a key sheet for a push button switch including a base sheet made of a rubber-like elastic body and a plurality of key tops fixed to the base sheet. A method for producing a decorative molded body that uses a screen printing plate having a dot pattern with different tone between key tops, prints a halftone printing layer at one time, and forms a gradation design across a plurality of key tops; can do.

  Use a screen printing plate in which each keytop has a single tone (no gradation difference) and a dot pattern with different tones among several keytops, and the halftone printed layer of the keytop is formed at once. Since the gradation design is formed by printing and forming a plurality of key tops as a whole, it is possible to easily produce a key sheet having an excellent fine and smooth gradation, and having an interesting and impactful effect.

  Thus, according to the decorative molded body and the method of manufacturing the decorative molded body of the present invention, not only can the difference in density between the darkest part and the thinnest part be increased, but also the gradation changes smoothly and finely. It is possible to obtain a decorative molded body having an excellent gradation and having a gradation design with interest and impact and a method for producing the same.

  Specific embodiments of the present invention will be described in detail with reference to the drawings. The decorative molded body in the present embodiment is a key top used for a mobile phone and a key sheet including the key top.

First Embodiment : The key top 11 of the present invention and the key sheet 12 including the key top 11 of the present invention shown as the first embodiment are used in the mobile phone 1 shown in FIG. 1, and a plan view of the key sheet 12 is shown. 2 is a schematic cross-sectional view of the key sheet 12. In addition, duplication description is abbreviate | omitted about the structure which is common in each embodiment.

  As shown in FIG. 3, the key top 11 is a decorative layer formed by laminating a diffusion layer 14, a halftone printing layer 15, and a base layer 16 on the back surface 13 a of a key top main body 13 made of a translucent resin. 17 is provided. The key top 11 is fixed to a base sheet 18 made of a rubber-like elastic body with an adhesive 19 to form a key sheet 12.

  Key top body 13; The key top body 13 is a molded body formed of a hard resin having translucency. The translucency here means a visible light transmittance of 3% or more. This is because light is transmitted even if the visible light transmittance is less than 3%, but it is difficult to visually recognize the gradation design formed on the back surface 13a through the key top body 13. The key top body 13 is more preferably transparent.

  Specifically, resins such as polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), vinyl chloride, acrylonitrile butadiene styrene (ABS), polyurethane (PU), epoxy, polypropylene, nylon, and alloys thereof. It can be molded using a resin such as a resin. PC and ABS are preferable from the viewpoints of moldability and translucency, and PMMA is preferably used from the viewpoint of surface hardness. The key top body 13 is formed by molding these resins into a predetermined key top shape by injection molding or the like in advance.

  Diffusion layer 14: The diffusion layer 14 diffuses and scatters transmitted light, blurs the dot pattern, and makes it visible as a gradation. In order to exhibit such a function, it is preferable that the total light transmittance of the diffusion layer 14 is high and the haze is high.

  The diffusion layer 14 may be a resin liquid added with a scattering agent, for example, acrylic, vinyl, polyester, acrylic / PC, ABS / PS, urethane, polyolefin, epoxy. Inorganic resin selected from calcium carbonate, crosslinked polymethyl methyl methacrylate, crosslinked polystyrene, barium sulfate, silicone, titanium oxide, mica, bismuth oxychloride, etc., alone or in combination, is dispersed in a resin selected from alkyds, etc. Can be mentioned. Among these resins, ABS / PS, vinyl, and acrylic / PC are preferable materials because they have high adhesion to resins such as acrylic resins used as the key top body 13. Among these inorganic fine particles, mica and bismuth oxychloride are preferable materials because they have not only a light diffusion effect but also a pearly luster.

  The resin may be a liquid resin or a resin dissolved in a solvent. The average particle size of the inorganic fine particles is preferably 0.1 μm to 50 μm. This is because when the particle diameter is within this range, the light diffusion effect is excellent and the resin liquid is stably dispersed. On the other hand, if the average particle size is larger than 50 μm, the unevenness on the surface of the diffusion layer 14 becomes large, and bubbles are involved when the halftone printing layer 15 is provided, or the dot pattern becomes unclear, and the average particle size is 0. If it is smaller than 1 μm, a light diffusing effect can be obtained, but disadvantages increase if the amount added is increased or dispersion becomes difficult. The content of the inorganic fine particles relative to the resin is preferably 1.0 wt% to 30 wt%. If the amount is less than 1.0 wt%, the light diffusion effect cannot be obtained. If the amount is more than 30 wt%, the light diffusion effect becomes high. However, the amount of light that is diffused easily increases, and the entire image becomes dark. Because it ends up.

  The diffusion layer 14 is formed by solid printing on the back surface 13a of the key top body 13 by a method such as printing or coating by appropriately diluting a resin liquid containing inorganic fine particles. Screen printing is the preferred technique. When the solvent-diluted resin is used, the solvent is evaporated, and when the curable resin is used, the diffusion layer 14 is obtained by performing a curing reaction according to the type. The layer thickness of the diffusion layer 14 varies depending on the average particle diameter of the inorganic fine particles to be added, but is preferably thinner than half of the average particle diameter of the inorganic fine particles.

  Halftone print layer 15; The halftone print layer 15 is a layer that is a basis of gradation in which a plurality of fine dots 15a are printed to form a dot pattern. Normally, gradation is formed such that the gradation changes gradually by changing the number and size of the dots 15a per unit area, but in the present invention, as shown in FIG. In addition, each of the individual key tops 11 arranged in 4 rows and 3 columns has a single dot pattern and only a single tone (no shade difference), which alone forms a gradation. Not. However, the three key tops 11a arranged in the first row, the three key tops 11b arranged in the second row, the three key tops 11c arranged in the third row, and the three key tops 11d arranged in the fourth row Overall, a gradation is formed in which the tone gradually changes from the first line to the fourth line. The enlarged view of the key top 11 shown in FIG. 2 is merely an example of a dot pattern, and the shape, size, and interval of the dots 15a can be variously changed as long as gradation is realized. .

  The halftone printing layer 15 can be formed by a method of printing a dot pattern, but it is preferable to use screen printing from the viewpoints of dot reproducibility and ink application amount. And it is preferable to use the resin ink which contains the inorganic microparticles | fine-particles as a thixotropic property imparting agent in a resin liquid for the ink for screen printing. Thixotropy refers to the function of increasing the residual stress by limiting the molecular motion of the resin. That is, with normal resin inks, the ink leveling is good, and the ink flows on the substrate to be printed, so that desired dots may be crushed and connected to adjacent dots. However, in order to obtain a high-quality gradation, it is necessary to prevent the ink from spreading and sagging on the substrate to prevent the spread of the dots, and the dots need to be printed accurately. Therefore, an ink with appropriate thixotropy is used. It is done.

  In the ink for halftone printing layer, acrylic resin, vinyl resin, polyester resin, acrylic / PC resin, ABS / PS resin, urethane resin, polyolefin resin, epoxy resin, alkyd resin, etc. can be used as a main component. . Moreover, aluminum oxide, talc, zinc oxide, silica, etc. can be used for the inorganic fine particles added as a thixotropic agent. These inorganic fine particles may be surface-treated or untreated. Moreover, you may use individually or as a mixture of multiple types. Among these inorganic fine particles, finely powdered silica such as fumed silica, which is untreated, is particularly good because the OH groups of SiOH groups (silanol groups) on the surface of the particles are hydrogen-bonded. This is probably because of this. Further, the untreated surface of fumed silica is particularly preferable when the halftone print layer 15 has high transparency and is used as the illuminated key top 11.

  The amount of inorganic fine particles added is preferably 0.1 wt% to 5.0 wt% in the ink solid content. This is because not only an appropriate thixotropy is imparted to the ink, but also the viscosity becomes appropriate. On the other hand, if it exceeds 5 wt%, the halftone printing layer 15 is liable to crack, becomes brittle, and the corrosion resistance decreases. On the other hand, if it is less than 0.1%, it does not have an appropriate thixotropy, the dot pattern becomes unclear, and a smooth gradation cannot be obtained.

Looking at the fine inorganic particles from the specific surface area is preferably at least 100 m ² / g in BET specific surface ^area, 105m ² / ^g~800m 2 / g is more preferable. This is because if the specific surface area is large, the thixotropic property is easily exhibited and the amount added can be suppressed. In addition, in order to increase the transparency of the halftone print layer 15, it is preferable to set it to about 350 m ² / g or more.

  The halftone printing layer 15 can be formed by preparing a plate on which a predetermined dot pattern is formed for each of the plurality of key tops 11 arranged on the base sheet 18 and forming the dot pattern by screen printing at a time. As a specific method, a 270 mesh, 130-line screen has a 40% dot arrangement density for the first row of key tops 11a, a 60% dot arrangement density for the second row of key tops 11b, Printing can be performed using a screen printing plate on which a plate film is formed so that the dot arrangement density of 80% is applied to the key top 11c of the third row and the dot arrangement density of 100% is applied to the key top 11d of the fourth row. it can.

  Underlayer 16: The underlayer 16 is characterized by being colored differently from the halftone print layer 15, and is a layer formed by solid coating so as to cover the entire surface of the halftone print layer 15. Here, the different color means that at least one of hue, brightness, and saturation is different. That is, for example, when the halftone print layer 15 is green, the base layer 16 is yellow. By applying the base layer 16 so as to overlap the back surface of the halftone print layer 15, a portion of the halftone print layer 15 where dots are not formed is filled with the base layer 16. Therefore, the underlayer 16 is formed using an ink or a paint excellent in leveling properties. If the leveling property is good, there is no particular limitation on methods such as printing and coating.

  The decorative layer 17 having the layer structure as described above is provided on the back surface 13a of the key top body 13 together with the display unit 20 representing characters and symbols. The key top 11 thus configured is fixed to a base sheet 18 made of silicone rubber, thermoplastic elastomer or the like with an adhesive 19 to form the key sheet 12. The base sheet 18 may be a rubber-like elastic body, and the adhesive 19 may be any one that fixes the key top 11 and the base sheet 18 together.

  The key sheet 12 is used by being incorporated in the mobile phone 1. In the example in which the halftone print layer 15 is green and the base layer 16 is yellow, when the cellular phone 1 that can be folded in half is opened and the key top 11 is viewed, the green of the dots 15a of the halftone print layer 15; Although the yellow color of the underlying layer 16 between the dots 15a appears, both are visible through the diffusion layer 14. For this reason, the dots 15a of the halftone print layer 15 are not clearly seen, and an excellent gradation that is fine and smooth that changes to dark green as the key top 11a in the first row transitions to the key top 11d in the fourth row. Is seen. On the other hand, a fine, smooth and excellent gradation that darkens in yellow as the key top 11d in the fourth row transitions from the key top 11a in the first row can be seen. Therefore, an excellent gradation design in which the gradations of both green and yellow are combined is obtained.

Second Embodiment ; The key top 21 of the present invention shown as the second embodiment and the key sheet 22 including the key top 21 are also used in the mobile phone 1 shown in FIG. 1, and the plan view thereof is the same as FIG. Appear in A schematic cross-sectional view of the key sheet 22 is shown in FIG.

  Compared with the key top 11 shown in the first embodiment, the decorative layer 17 of the key top 11 and the layer structure thereof are the same, but in the key top 11, the decorative layer 17 is formed on the back surface 13a of the key top body 13. In contrast to this, the key top 21 of the present embodiment is different in that a decoration layer 27 is formed on the upper surface 23 b of the key top body 23. That is, in the key top 21, the base layer 26, the halftone printing layer 25, and the diffusion layer 24 are laminated in this order from the key top main body 23 side. The display unit 30 is provided on the upper surface 23 b of the key top body 23.

  The ink and paint for forming each layer can be the same as those for forming the key top 11 shown in the first embodiment. However, in this embodiment, the base layer 26 is provided before the halftone print layer 25. Therefore, it is not necessary to use ink having particularly good leveling properties for forming the underlayer 26. Moreover, since the decoration layer 26 is not visually recognized through the key top main body 23, the material used as the key top main body 23 may be a material with poor transparency.

  Similarly to the key sheet 12 according to the first embodiment, the key sheet 22 according to the second embodiment also has an excellent gradation design that has a large gradation difference and allows a fine and smooth gradation to be seen.

Other Embodiments Various modifications can be made to the above embodiments.

  Any one of the halftone printing layers 15 and 25 or the base layers 16 and 26 may be white. If either one is white, a distinctive gradation of the other color can be obtained. For example, as a modification of the key top 11 of the first embodiment, if the base layer 16 is formed in white instead of yellow, a green gradation can be clearly seen in a white background. Therefore, it has a gradation design that can be recognized as a key top with a gradation of green alone. In addition, when one of them is a metal color or black, it is possible to obtain a gradation in which the brightness and saturation of the other color are different.

  In the case of a so-called illuminated key top that emits light from a light source provided inside the device and illuminates the key tops 11 and 21, not only the diffusion layers 14 and 24 but also the halftone printing layers 15 and 25, The base layers 16 and 26 and the key top body 23 in the second embodiment also need to use a translucent material. Even in the illuminated key sheets 12 and 22 using such a material, an excellent gradation can be seen without the dots 15a being visually recognized.

  In addition to the layers shown in the above embodiment, other layers can be formed in order to add various functions. For example, it is possible to provide a metal thin film layer for giving a metallic hue, a protective layer for protecting a predetermined layer, or the like. Moreover, the positions where the display units 20 and 30 representing characters and symbols are formed can be changed as appropriate.

  The decorative molded body in the above embodiment is the key tops 11 and 21 used for the mobile phone 1 and the key sheets 12 and 22 including the key tops 11 and 21, but the key tops 11 and 21 and the key sheets 12 and 22 The decorative molded body other than 22 can be applied to, for example, the cellular phone 1 and the housings of various electric / electronic devices.

The external appearance top view of a form telephone. The top view of the key sheet (decoration molding) by 1st Embodiment of this invention. FIG. 3 is a sectional view taken along line SA-SA in FIG. 2. Sectional drawing equivalent to FIG. 3 of the key sheet by 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cellular phone 11, 21 Key top 11a, 21a First row key top 11b, 21b Second row key top 11c, 21c Third row key top 11d, 21d Fourth row key top 12, 22 Key sheet 13, 23 Key top body 13 a Back surface 23 b Upper surface 14, 24 Diffusion layer 15, 25 Halftone printing layer 15 a, 25 a Dot 16, 26 Base layer 17, 27 Decorating layer 17, 28 Base sheet 19, 29 Adhesive 20, 30 display unit

Claims (10)

In a decorative molded body in which the molded body is decorated with a color design,
A gradation design formed by laminating a diffusion layer for diffusing transmitted light, a halftone printing layer for forming a dot pattern, and a base layer colored differently from the halftone printing layer is formed on the molded body. A decorative molded body having.   The decorative molded body according to claim 1, wherein the halftone printed layer and the underlayer are chromatic colors having different colors.   The decorative molded body according to claim 1, wherein one of the halftone printed layer and the underlayer is white.   The decorative molded body according to claim 1, wherein at least one of the halftone printed layer and the underlayer is a metal color.   The decorative molded body according to any one of claims 1 to 4, wherein the halftone printed layer is a layer containing 0.1 wt% to 5.0 wt% of inorganic fine particles formed of screen printing ink.   The decorative molded body according to any one of claims 1 to 5, wherein the molded body is a key top for a pushbutton switch. In the method of manufacturing a decorative molded body in which the molded body is decorated with a color design,
A light-transmitting molded article is provided with a diffusion layer for diffusing transmitted light, then provided with a halftone printing layer for forming a dot pattern by screen printing, and then a base layer having a different color from the halftone printing layer A method for producing a decorative molded body having a gradation design, characterized in that the above is provided. In the method of manufacturing a decorative molded body in which the molded body is decorated with a color design,
The molded body is provided with a base layer, then provided with a halftone print layer for forming a dot pattern different from the base layer by screen printing, and then provided with a diffusion layer for diffusing transmitted light. A method of manufacturing a decorative molded body with a gradation design.   The method for producing a decorative molded body according to claim 7 or 8, wherein screen printing ink containing 0.1 wt% to 5.0 wt% of inorganic fine particles in the solid content is used for printing of the halftone printing layer. The molded body is a key sheet for a pushbutton switch including a base sheet made of a rubber-like elastic body and a plurality of key tops fixed to the base sheet, and each key top has a single tone, 10. A gradation design is formed on a plurality of key tops by printing a halftone printing layer at a time using a screen printing plate having a dot pattern having a different tone between key tops. The manufacturing method of the decorative molded body of description.

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