Abstract:
A method for forming three-dimensional patterns on a molded particle utilizing a mold with a male mold and a female mold defining a mold cavity, a three-dimensional pattern provided inside the mold cavity; providing an attachment film; transporting the attachment film into the mold, and providing a predetermined section of the attachment film closely applied to the mold cavity; closing the mold; closing the mold again, enabling the parting surface of the male mold and the parting surface of the female mold to contact each other, and cutting the predetermined section from the attachment film; stopping injection of plastic material; opening the mold and pushing out a molded article with three dimensional patterns corresponding to the patterns provided inside the mold cavity. A molded article made of the foregoing method is also disclosed.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present application is related to formation of three dimensional patterns in-mold on molded articles and articles molded by the method. 
         [0003]    2. Description of Related Art 
         [0004]    Portable electronic devices (such as mobile phones and electronic notebooks) are in widespread use. The external appearance of the housing of the portable electronic device has become a key factor for attracting consumers. 
         [0005]    The external appearance of the housing is often made by In-Mold Roller (IMR) process. The IMR process comprises: printing ink on a film to form an ink layer, positioning the film to correspond to the mold cavity of the a mold by a transporter, closing the mold, injecting plastic material into the mold cavity, opening the mold and separating the ink layer from the film. The film also comprises a separation layer and a hardening layer, both stripped from the molded article after opening the mold. Edges of the hardening layer are not flush with edges of the ink layer attached on the molded articles. Thickness of the hardening layer is usually less than five micrometers, so it is easy to be scratched. After being stripped off, the separation layer and the hardening layer can not be used again. 
         [0006]    Therefore, a method providing a decoration layer on a molded article with lower cost and increased hardness is desired. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a cross-section view of a mold used in an embodiment of a method for forming three-dimensional patterns on molded articles inside a mold as disclosed. 
           [0008]      FIG. 2  is a cross-section view of another mold used in the method for forming three-dimensional patterns on molded articles as disclosed. 
           [0009]      FIG. 3  is a drawing showing a first closing status of the mold of  FIG. 1 , the male mold and the female mold not in contact, and melted plastic material prepared for injection into the mold. 
           [0010]      FIG. 4  is a drawing showing a second closing status of the mold of  FIG. 1 , with the male mold and the female mold in contact, and the injection of melted plastic material is completed, meanwhile a cutting part of the male mold cuts down a predetermined section of the attachment film. 
           [0011]      FIG. 5  is a flowchart of a first embodiment of a method for forming three-dimensional patterns on molded articles inside a mold as disclosed. 
           [0012]      FIG. 6  is a flowchart of a second embodiment of a method for forming three-dimensional patterns on molded articles inside a mold as disclosed. 
           [0013]      FIG. 7A  is a perspective view of a molded article formed by the method disclosed. 
           [0014]      FIG. 7B  is a cross-section view taken along a line  7 B- 7 B in  FIG. 7A . 
           [0015]      FIG. 8A  is a perspective view of another molded article formed by the method as disclosed. 
           [0016]      FIG. 8B  is a cross-section view taken along a line  8 A- 8 B in  FIG. 8A . 
           [0017]      FIG. 9  is a partial, cross-section view taken along a line  9 - 9  in  FIG. 7B , showing three-dimensional patterns of an attachment film. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]      FIG. 1  is a cross-section view of a mold used in an embodiment of a method for forming three-dimensional patterns on molded articles as disclosed. The mold comprises a transporter  15 , a female mold  25  and a male mold  30 . The transporter  15  comprises a pair of film transporting rollers (not labeled), provided on the upper side and the lower side of the mold respectively, to transport the film. The transporter  15  also comprises a direction roller (not labeled) to direct the film to a correct transport position. 
         [0019]    A mold cavity  22  is provided in the female mold  25 . A three-dimensional pattern  222  can be provided in the bottom of the mold cavity  22  through chemical etching or curving by cutting tools. The three-dimensional pattern  222  also can be obtained by applying photoresistance on a predetermined section of the substrate of the female mold in a predetermined pattern, followed by exposure and development with the photoresistance on the predetermined section. 
         [0020]    Several exhaust slots are provided on one side of the female mold  25  opposite to the mold cavity, connected to an exhausting device, to make the film sent by the transporter  15  attached inside the mold cavity  22 . 
         [0021]    The male mold  30  comprises a parting surface on which a recess  24  is defined. The male mold  30  also comprises a cutting part  26  to cut a predetermined section of the film which corresponds to the mold cavity  22  of the female mold  25 . An injection nozzle is provided on the center of the accommodative part to inject melted plastic material into the mold cavity  22  of the female mold  25 . As shown in  FIG.2 , another embodiment of a mold, a recess  24 ′ can be defined on the parting surface of the female mold  25  along the mold cavity  22 , and a cutting part  26 ′ is formed around the mold cavity  22 . 
         [0022]    In  FIG. 5 , a flowchart of a first embodiment of a method for forming three-dimensional patterns on a molded article shows. In block S 101 , a three dimensional pattern is formed within the mold cavity  22  of the female mold  25 . In block S 102 , an attachment film  100  is provided. In block S 104 , the attachment film  100  is transported to the position between the female mold  25  and the male mold  30  along the parting surface of the female mold  25  by the transporter  15 . A determined portion of the attachment film  100  is attached to the inner side of the cavity  22  of the female mold  25 , which comprises a three dimensional pattern. The attachment is preferably implemented by exhausting air from inside the mold cavity  22 , with the attachment film  100  attached closely to the mold cavity  22  thereby. 
         [0023]    In block S 106 , the mold is closed for a first time, and a parting surface of the male mold  30  and a parting surface of the female mold  25  do not contact each other. In block S 108 , melted plastic material is injected into the mold cavity  22  until 90%-95% of the space of the mold cavity  22  is filled, and a mold base is formed. The attachment film  100  is now attached on the surface of the mold base and a dimensional pattern is formed on the attachment film. 
         [0024]    In block S 110 , the mold is closed again, and the parting surface of the male mold  30  and the female mold  25  contact each other. As shown in  FIG. 4 , melted plastic material is injected into the mold. Squeezed by the male mold  30 , the cutting part  26  of the male mold  30  cuts off the predetermined section of the attachment film  100  attached on the mold base with the three dimensional pattern corresponding to the pattern  222 . In step S 112 , melted plastic material injection stops. In step S 114 , the mold is cooled. In step S 116 , the mold is opened, and a molded article is obtained. Commensurately, the transporter  15  removes the attachment film  100  from the male mold  30  and the female mold  25 , and a subsequent molding cycle begins. 
         [0025]      FIG. 6  is a flowchart of a second embodiment of a method for forming three-dimensional patterns on a molded article. In block S 201 , a three-dimensional pattern is formed in the inner side of the mold cavity  22 . In block S 202 , a serial attachment film  100  is provided. In block S 204 , the serial attachment film  100  is transported to a position between the female mold  25  and the male mold  30  along the parting surface of the female mold  25  by the transporter  15 . The mold comprises a cutting part  26 . The transportation process can be referred to  FIG. 3 . In block S 206 , the mold is closed. In block S 208 , melted plastic material is injected into the mold cavity  22  to form a mold base, and the attachment film  100  is attached on the mold base. In block S 210 , the attachment film  100  attached on the mold base with a three-dimensional pattern corresponding to the pattern in block S 201  is cut off from the serial attachment film by the cutting part  26  or  26 ′. In block S 212 , injection of melted plastic material is completed. In block S 214 , the mold is cooled. In block S 216 , the mold cavity is opened, and a molded article is obtained. The molded article have the attachment film  100  with a three-dimensional pattern corresponding to the pattern in block S 201 . 
         [0026]    Molded articles formed by the method of the present application have colorful three-dimensional patterns with higher hardness than those made by conventional molding techniques, and are not easily damaged by abrasion. Furthermore, molded articles formed by the method of the present application have uneven and rough surface that are able to prevent slight oil dirt. The disclosed method is suitable for serial automatic production, and has increased efficiency and quality in molding articles. 
         [0027]    Please refer to  FIG. 7A  and  FIG. 7B , showing a shell  10  formed by the method disclosed, comprising a substrate  200  and an attachment film  100  with a three-dimensional pattern corresponding to the pattern  222 . The substrate  200  comprises a top surface  201  and an edge  202  surrounding the top surface  201 . The attachment film  100  is attached on and envelopes the top surface  201 . 
         [0028]      FIG. 8A  and  FIG. 8B  show another shell  20  formed by the method disclosed, comprising a substrate  300  and an attachment film  500  with a three-dimensional pattern corresponding to the pattern  222 . The substrate  300  comprises a top surface  301  and an edge  302  surrounding the top surface  301 . The attachment film  500  is attached on the substrate  300  enveloping the top surface  301  and the side edge  302 . 
         [0029]    Please refer to  FIG. 9 , a cross-section view along a line  9 - 9  in  FIG. 7B , in which the attachment film  100  comprises a base layer  103 , a decoration layer  104  and an adhesive layer  106 . The base layer  102  is scrolled and received in the transporter, and a three-dimensional pattern is formed by squeezing the base layer  102  with the three dimensional pattern  222  in the mold cavity  22 . The three-dimensional pattern is attached to surface of the base  200 , protecting the decoration layer  104  and the base  200  from abrasion and scratching. The base  102  generally is made of one or more material consisting of: polycarbonate (PC), polyethylene terephthalate (PET), Polymethylmethacrylate (PMMA), oriented polypropylene (OPP), and polyvinyl chloride (PVC). The thickness of the base layer  102  is preferably within a range from 0.01 millimeters to 0.125 millimeters (mm). 
         [0030]    The decoration layer  104  is formed on the base layer  102  by color ink application to provide color or patterns. The decoration layer  104  can also be formed by vapor deposition or sputtering of a metal layer on the base layer  102 , to provide a metallic sheen. The metal can be selected from one or more material in the group consisting of aluminum, chrome, copper, nickel, indium, and tin. 
         [0031]    The adhesive layer  106  combines the attachment film  100  with the substrate  200 . The adhesive layer  106  can be made by one or more material selected from the group consisting of: polyurethane resin, chlorinated rubber, vinyl chloride-vinyl acetate copolymer resin, polyamide resin, polyester resin, epoxy resin, polycarbonate resin, alkene resin, and vinyl cyanide-butylene-styrene resin. The adhesive layer  106  can be printed on the base layer  102  by gravure printing, screen printing, or flexography. The adhesive layer  106  can also be applied on the base layer  102  by spray coating or brush coating. 
         [0032]    The base layer  102  of the attachment film  100  is embodied as transparent or translucent to show patterns and color of the decoration layer  104 , which corresponds to the three-dimensional pattern  222  of the mold cavity  22 . 
         [0033]    The substrate  200  includes a second end surface  201  of a circumferential edge, and the attachment  100  includes a first end surface  101  of a circumferential edge, wherein the second end surface  201  of a circumferential edge is flush with the first end surface  101  of a circumferential edge. 
         [0034]    While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.