Patent Application
20110039059
1. Technical Field
The present disclosure relates to molding articles, and particularly to a molding article having an EMI shielding film thereon.
2. Description of Related Art
Electro magnetic interference (EMI) has been a big environment problem for people. Various electronic devices such as mobile phones subject users to EMI.
Metal is known as an EMI shielding material. Currently, more and more shells of electronic devices are covered by metal to provide EMI shielding.
However, the shells are usually molded beforehand, and then coated with metal by some complicated depositing method.
What is needed, therefore, is a molding article with an EMI shielding film and a method for making same, which can overcome the above shortcomings
Many aspects of the present molding article and method can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present molding article and method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Embodiments of the present molding article and method will now be described in detail below and with reference to the drawings.
Referring to
The base 11 is made of or at least includes a thermoplastic material. The base 11 is made by an injection molding method, and can have different shapes according to need.
The EMI shielding film 12 is composed of carbon nanotubes and a polymer matrix. The carbon nanotubes are configured as a major part of the EMI shielding film, and the polymer matrix is configured as a minor part of the EMI shielding film, i.e., a volume of the carbon nanotubes is greater than that of the polymer matrix. In other words, the EMI shielding film 12 is a carbon nanotube-based film. The carbon nanotubes are parallel with each other with central axis thereof along a direction perpendicular to a main surface of the EMI shielding film 12 and perpendicular to a main surface of the base 11 where the EMI shielding film 12 is adhered on. The carbon nanotubes may contain carbon nanotube segments joined end-to-end along the central axis thereof by Van der Waals force. The carbon nanotubes have good electrical conductivity, such that the carbon nanotubes are good at shielding EMI. The polymer matrix is dielectric. The polymer matrix is configured for increasing wettability between the film 12 and the base 11.
The EMI shielding film 12 can be made very thin because of its excellent EMI shielding ability, and thus is transparent to light. The carbon nanotubes can have diameters of about 100 nanometers. The EMI shielding film 12 is transparent, such that colors of the base 11 can are still visible.
Referring to
First, a preformed carbon nanotube-based electro magnetic interference (EMI) shielding film 15, and a mold 13 including an upper mold 131 and a lower mold 132 are provided. The carbon nanotube-based EMI shielding film 15 is the same as the EMI shielding film 12 detailed above. The upper mold 131 and the lower mold 132 cooperatively define a cavity 14 therein, and the cavity 14 has a molding surface 142 at the lower mold 132. The shape of the cavity 14 can be changed according to need.
Second, the carbon nanotube-based EMI shielding film 15 is attached on the molding surface 142. The carbon nanotube-based EMI shielding film 15 can be attached to the molding surface 142 by a vacuum suction method or by adhesive.
Third, a thermoplastic material (not labeled) is injected in the cavity 14, adhered to the carbon nanotube-based EMI shielding film 12.
Fourth, the carbon nanotube-based EMI shielding film together with the thermoplastic material is ejected, thereby obtaining the molding article including a base made of the thermoplastic material and the carbon nanotube-based EMI shielding film 15 adhered to the base.
In other embodiments, the carbon nanotube-based EMI shielding film 15 is first attached to a flexible substrate, and the flexible substrate is then attached to the molding surface 142. After the base and the carbon nanotube-based EMI shielding film 15 together with the flexible substrate are ejected out from the mold 13, the flexible substrate can be peeled off.
It is understood that the above-described embodiments are intended to illustrate rather than limit the disclosure. Variations may be made to the embodiments and methods without departing from the spirit of the disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200910305528.9 | Aug 2009 | CN | national |
