This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 101115246 filed in Taiwan, R.O.C. on 2012 Apr. 27, the entire contents of which are hereby incorporated by reference.
1. Technical Field
The present invention relates to a film structure, and more particularly to a multilayer decorative film structure for decorating multiple processing surfaces of a preformed three-dimensional structural part in a secondary/post processing manner.
2. Related Art
At present, for external three-dimensional structural parts of a product, such as a case, a panel, and a decorative part of an electronic device, their surfaces have a more diversified structural modeling design. The three-dimensional structure of an external three-dimensional structural part may include a local convex or concave form or a bending side edge, which is suitable for integrated printing or attachment processing.
For such an external three-dimensional structural part, in the common conventional surface decoration processing technology, methods such as paint spraying, electroplating, or sputtering are applied on a surface of the external three-dimensional structural part to form a decorative layer, so that the surface of the external structural part has specific colors, or provides a surface tactile sense of a smooth or matte surface. However, the decorative layer formed by using the foregoing mode usually only shows different colors or textures on the plane, and is not easy to form different kinds of geometric lines or patterns. Furthermore, chemical agents used in paint spraying and electroplating processes, or noxious chemical agents used in the processes such as benzene and alcohol related medicaments, volatilize into the air to result in air pollution. Even worse, the discharge of sewage containing emitted heavy metal pollutants such as nickel, chromium, cadmium, and copper leads to serious environmental pollution.
The high-cost in-mold decoration (IMD) technology is a brand-new technology, in which a plastic film is placed into a plastic injection mold of a plastic injection shaping machine to perform the surface treatment on the appearance of plastics.
In-mold label (IML) is a first kind of IMD technologies. In the engineering method, a pattern in the surface treatment is printed on a film in advance, the film is placed in a mold cavity, and injection shaping is performed. At the same time of performing the injection shaping, ink is transferred onto a plastic part by using the plastic heat. After the mold is opened and the plastic part is ejected, the two steps, that are, shaping and pattern transfer printing, are completed. A disadvantage of the IML is that it cannot be used in the surface treatment in a case of complicated shape, and is only applicable to a plastic injection shaping container of a box or cup shape.
In-mold roller (IMR) is a second kind of IMD technologies. In the engineering method, a pattern is printed on a film, and the film is wrapped around a film reel, and a film feeding device attaches a diaphragm to a shaping cavity to perform the injection shaping. After the injection shaping, an ink layer with a pattern is separated from the film and left on the plastic part to obtain a plastic part with a decorative pattern on the surface. There is no transparent protective film on the surface of the final product, and the diaphragm is just a carrier in the production. IMR is one of the mainstream surface treatment technologies of plastic cases of notebook computers. However, a disadvantage of IMR is that a printed pattern layer is likely to wear off and fade; in addition, the change of a processable curved surface cannot be too great. Therefore, IMR is not applicable to the cases with special modeling.
In-mold film (IMF) is a third kind of IMD technologies. In the engineering method, a film itself first undergoes steps such as softening and vacuum shaping; after the 3D shaping is completed, surface treatment is performed. The IMF engineering method is not applicable to mass production, and its cost is about 20% higher than that of IMR. Consequently, IMF is less popular than IMR.
An advantage of IMD technologies is that the IMD technologies integrate the plastic injection process and the surface treatment process, so that shaping and decoration of an ejected structural part are completed in one pass. However, for a preformed, especially a non-plastic external three-dimensional structural part, IMD technologies cannot be used to perform the secondary processing.
Accordingly, the present invention provides a multilayer decorative film structure used to be attached to and shaped on multiple processing surfaces of a preformed three-dimensional structural part, where the processing surfaces form a three-dimensional shape. The multilayer decorative film structure includes an adhesive layer and a bilayer structure. The adhesive layer is used to adhere to the processing surfaces of the preformed three-dimensional structural part; the bilayer structure is located at a side of the adhesive layer and includes a thermoplastic film and a decorative film. The thermoplastic film is 0.05 mm to 1 mm thick and has an inner surface and an outer surface; the decorative film is laminated at a side of the thermoplastic film, is 1 μm to 1 mm thick, and has a decorative structure. A thermal shaping temperature of the multilayer decorative film structure ranges from 80 to 250 degrees centigrade. Within the thermal shaping temperature range, the bilayer structure and the adhesive layer may be attached to and shaped on processing surfaces of the preformed three-dimensional structural part. When the temperature is lower than the thermal shaping temperature range, the bilayer structure and the adhesive layer may be solidified into a shape the same as a three-dimensional shape of the processing surfaces.
The multilayer decorative film structure according to the present invention is used to be attached to and shaped on processing surfaces of a preformed three-dimensional structural part and decorate the preformed three-dimensional structural part, so that the structural part is visually appealing; and the multilayer decorative film structure features a color structure, a pattern structure, a line structure, and a reflective structure as well as any combination thereof, thereby meeting the requirements for diversification of surface designs of products at present to achieve different visual effects and textures. By replacing the prior art effectively, the present invention avoids serious environmental pollutions caused by paint spraying and electroplating decoration industries, such as air, water source, and soil pollutions, which conforms to the environmental protection concept which is attracting more and more attention. The decorative processing surfaces according to the present invention are applicable to various products such as 3C products, household appliances, articles for daily use, decorative building materials, bicycles, and parts of automobiles and locomotives.
The detailed features and advantages of the present invention are described below in detail through the following embodiments, and the content of the detailed description is sufficient for persons skilled in the art to understand the technical content of the present invention and to implement the present invention accordingly. Based upon the content of the specification, the claims, and the drawings, persons skilled in the art can easily understand the relevant objectives and advantages of the present invention.
The present invention will become more fully understood from the detailed description given herein below for illustration only, and thus not limitative of the present invention, wherein:
The multilayer decorative film structure of the present invention is applicable to the secondary processing of a preformed three-dimensional structural part. The preformed three-dimensional structural part refers to an external three-dimensional structural part which is shaped and manufactured in advance. The material thereof may be a plastic or non-plastic material, and for example, may be selected from the group consisting of polycarbonate (PC), acrylonitrile butadiene styrene (ABS), PC/ABS resin composite material, nylon, alloy, memory alloy, metal, hard rubber, soft rubber, foaming material, hard plastic, soft plastic and any combination thereof. In an actual example, the preformed three-dimensional structural part may be a housing or protective case of a mobile electronic device such as a mobile phone, a notebook PC, or a tablet PC and their peripheral products, or a housing or decorative panel of other household appliances such as an air conditioner, a TV, an audio apparatus, a refrigerator, an air cleaner, and a dehumidifier, but the present invention is not limited to this. The preformed three-dimensional structural part has multiple consecutive processing surfaces and the consecutive processing surfaces are located on different planes, so a special three-dimensional shape is formed. For different preformed three-dimensional structural parts, each processing surface may be a plane, a cambered surface, or an irregular curved surface which has different locations and sizes and may have holes or cavities with different shapes. For a protective case attached to a back and sides of a smart mobile phone, main processing surfaces of the protective case may usually be one back face and four side faces, but due to differences in the whole design and shaping, the three-dimensional shapes formed by different processing surfaces on the housing are not exactly the same. Since it is not limited by the environment of the injection shaping process, the multilayer decorative film structure using the secondary processing apparently has a wide material choice in a decorative effect. However, to adapt to different three-dimensional shapes formed on different processing surfaces, the multilayer decorative film structure should have a thermoplastic processing effect. Furthermore, the multilayer decorative film structure also needs to have a feature that the structure can still maintain a fixed shape at a normal temperature or a temperature which is two to three times of the normal temperature, so that a finished product is unlikely to deform when affected by the environmental temperature. Therefore, the application of a thermal curing material should be excluded from the multilayer decorative film structure according to the present invention.
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In some embodiments, the multilayer decorative film structure 1 may be heated to the foregoing thermal shaping temperature range, through a heating mold 3 or in other heating ways. At this time, negative pressure air pumping is applied to form a vacuum environment, so that the multilayer decorative film structure 1 is closely attached to multiple processing surfaces 21 of the preformed three-dimensional structural part 2, so as to form a rectangular case with a three-dimensional shape the same as that of the whole processing surfaces 21. After the attachment and shaping process in
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The bilayer structure 13 mainly includes the thermoplastic film 131 and the decorative film 132. The thermoplastic film 131 has an inner surface 131b and an outer surface 131a, where the surface close to the processing surfaces 21 of the preformed three-dimensional structural part 2 is referred to as an inner surface 131b, and the surface far away from the processing surfaces 21 of the preformed three-dimensional structural part 2 is referred to as an outer surface 131a. In
The adhesive layer 12 is sticky and is used to adhere onto the processing surfaces 21. In an embodiment, a thickness of the adhesive layer 12 ranges from 1 μm to 1 mm, and in some embodiments, the adhesive layer 12 may be implemented by a hot melt adhesive. In an embodiment, an implantation mode of the adhesive layer 12 is that the adhesive may be formed at a side of the bilayer structure 13 in a coating or spraying manner. In other embodiments, the adhesive layer 12 may also be implemented by a thermoplastic adhesive layer or thermoplastic adhesive film featuring a thermal shaping property, where the thermoplastic adhesive layer or thermoplastic adhesive film may be in the foregoing thermal shaping temperature range to provide attachment and shaping functions to the multilayer decorative film structure 1.
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Furthermore, when a depth of the decorative structure 132a at the outer side of the decorative film 132 in
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Furthermore, if many beads (transparent glass beads, or beads made of metal or with metal surfaces), and/or reflective surfaces (surfaces made of aluminum and its alloys, silver and its alloys, mica, shell powder, or pearl powder, and so on), are distributed on the decorative structure 132a at the outer side of the decorative film 132 and are used a reflective structure, because the decorative film 132 corresponds to the three-dimensional line structure 131c of the outer surface 131a of the thermoplastic film 131 in a concavo-convex manner, the decorative structure 132c at the outer side of the decorative film 132 forms a reflective structure facing a plurality of directions (a complicated multi-face structure formed to be of a wave shape or other three-dimensional shapes), thereby providing a better effect of multi-directional reflection and scattering.
In summary, the multilayer decorative film structure provided in the present invention may be attached to and shaped on multiple processing surfaces of different kinds of preformed three-dimensional structural parts in a proper processing environment and be formed of a special three-dimensional shape identical to a shape constructed by the processing surfaces. The thicknesses of the adhesive layer, the thermoplastic film and the decorative film may be adjusted according to requirements so as to form different decorative effects. In a general usage environment, if the temperate is lower than the thermal shaping temperature range of the multilayer decorative film structure, the curing state of the multilayer decorative film structure may be maintained, and warping deformation or shedding thereof may be avoided.
While the present invention has been described by the way of example and in terms of the preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures.
Number | Date | Country | Kind |
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101115246 | Apr 2012 | TW | national |