Polymer Graphene Electronic Housing

Abstract

To address issues related to EMI and ESD housings, and other issues related to EMI shielding and ESD protection.SOLUTION: An electronic component housing defining an EMI shield and an ESD protection cover includes a polymeric core formed from a first polymeric material with a reinforcement material, and an overmolded outer layer formed from a second polymeric material with about 2 wt.% to about 30 wt.% of graphene. The reinforcement material provides structural reinforcement to the electronic component housing and is at least one of carbon fiber, glass, talc, mineral filler, and combinations thereof. The overmolded outer layer defines a housing skin disposed on the polymeric core.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates generally to polymeric component housings, and more specifically to polymeric component housings for electronic devices. [Background technology]

[0002] The background provided herein is intended to provide a general context for the present disclosure. The work of the inventors to the extent that it may be described in this background section, as well as aspects of the present specification that may not be admitted as prior art at the time of filing, are not admitted expressly or impliedly as prior art to the present technology.

[0003] Electronic circuits in electronic devices, especially electric motors, electric powertrains, radar sensors, vehicle speed sensors, electric locks, radios, consoles, etc., emit electromagnetic (EM) radiation. Such EM radiation can also interfere with other electronic devices (e.g., electronic control units (ECUs)) that are in close proximity to the EM radiation-emitting electronic device. EM radiation interference is known as Electromagnetic Interference (EMI), and EMI shielding is used to attenuate EM radiation by reflection and / or absorption. Electronic devices may also require protection from electrostatic discharge (ESD), which can result from the discharge or build-up of static electricity.

[0004] Conventional EMI and ESD protection solutions include conductive metal housings, polymer housings with electroless or electrolytic plated metal coatings, polymer housings with conductive spray coatings, and polymer housings with metallization coatings (e.g., vacuum deposited or sputtered coatings). However, conductive metal housings have weight, size, and design flexibility limitations, electroless metal, electrolytic plated metal, or polymer housings with metallization coatings have environmental health & safety (EHS) and waste disposal limitations, and conductive spray coatings can have coating adhesion limitations. Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure addresses issues related to EMI and ESD housing as well as other issues related to EMI shielding and ESD protection. [Means for solving the problem]

[0006] This section provides a general overview of the disclosure and is not a comprehensive disclosure of its entire scope or all features. In one aspect of the present disclosure, an electronics housing is provided that includes a polymer core and an outer overmolded layer, the polymer core being formed from a first polymer material, the outer overmolded layer being formed from a second polymer material having graphene, and the outer overmolded layer defining a housing skin disposed on the polymer core.

[0007] In another aspect of the present disclosure, an electronics housing defining an EMI shield and an ESD protective cover includes a polymer core formed from a first polymer material having a reinforcing material, and an outer overmolded layer formed from a second polymer material and about 2% to about 30% graphene by weight, the reinforcing material providing structural reinforcement to the electronics housing and being at least one of carbon fiber, glass, talc, inorganic fillers, and combinations thereof, and the outer overmolded layer defining a housing skin disposed on the polymer core.

[0008] In yet another aspect of the present disclosure, a method of manufacturing an electronics housing defining an EMI shield and an ESD protective cover includes injection molding a first polymeric material having a reinforcing material to form a polymeric core using a two-shot injection molding machine, and injection molding a second polymeric material having about 2% to about 30% by weight of graphene to form an overmolded outer layer defining a housing skin on the polymeric core using the two-shot injection molding machine. The reinforcing material is at least one of carbon fiber, glass, talc, inorganic fillers, and combinations thereof to provide structural reinforcement to the electronics housing. Also, the polymeric core has a thickness of about 1 mm to about 10 mm, the housing skin has a thickness of about 0.5 mm to about 5 mm, the polymeric core with the housing skin has a shielding efficiency of about 35 dB to about 90 dB for EM radiation frequencies of about 1 GHz to about 40 GHz, and / or the polymeric core with the housing skin has a shielding efficiency of about 10 dB to about 90 dB for EM radiation frequencies of about 1 GHz to about 40 GHz. -10 S / m and approximately 10 -6 Antistatic conductivity of less than 10 S / m and approx. -8 S / m and approximately 10 -3 It has both or either an electrostatic discharge conductivity of less than S / m.

[0009] Other areas of applicability and various enhancements of the above techniques will become apparent from the description provided herein. The description and specific examples in this summary are for illustrative purposes only and are not intended to limit the scope of the disclosure.

[0010] The present teachings will become more fully understood from the detailed description and the accompanying drawings, wherein: [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a vehicle equipped with an electronic control unit (ECU). [Diagram 2] FIG. 2 is an exploded view of the ECU of FIG. 1 with an EMI shield and / or ESD protective cover in accordance with the teachings of the present disclosure. [Diagram 3] FIG. 3 is a cross-sectional view taken along the line 3-3 in FIG. 2. [Figure 3A] FIG. 3 is an enlarged view of portion 3A of FIG. [Figure 4A] FIG. 2 is a cross-sectional view of a polymer core of an ECU housing formed in a first mold set in accordance with the teachings of the present disclosure. [Figure 4B] FIG. 4B is a cross-sectional view of the polymer core of FIG. 4A disposed within a second mold set in accordance with the teachings of the present disclosure. [Figure 4C] FIG. 2 is a cross-sectional view of an outer overmolded layer formed on a polymer core in a second mold set in accordance with the teachings of the present disclosure. [Diagram 5] 1 is a cross-sectional view of an ECU housing for EMI shielding and / or ESD protection formed in a two-shot injection molding process in accordance with the teachings of the present disclosure. [Figure 6] 1 is a flowchart of a method of configuring an ECU housing for EMI shielding and / or ESD protection in accordance with the teachings of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present disclosure provides an electronics housing (also referred to herein simply as a "housing") comprising a polymer core (also referred to herein or known as a "polymer layer" and a "polymer substrate" or a "polymer layer" or a "polymer substrate") and an overmolded outer layer defining a housing skin disposed on the polymer core. The polymer core can be formed of a first polymer material with an added reinforcing material, and the overmolded outer layer can be formed of a second polymer material with an added graphene and / or carbon black, and the housing provides EMI shielding and / or ESD protection for an electronic device. For example, the housing provides EMI shielding and / or ESD protection for an ECU contained at least in part within the housing and located in close proximity to other electronic devices emitting EM radiation. In this manner, a lightweight EMI shielding and / or ESD protection cover is provided for one or more ECUs of a vehicle.

[0013] In some variations of the present disclosure, a two-shot injection molding or overmolding of a conductive polymer layer rich in graphene and / or carbon black onto a polymer core is used to form a housing that overcomes the problems of conventional shielding solutions. For example, the housing is manufactured through a large-scale two-shot molding process so that it is lighter than metal or metal fiber reinforced polymer housings and may not require secondary operations such as bonding, welding, etc. Also, by using the same base resin system for the polymer core and the housing skin, adhesion and durability issues may also be eliminated. Injection molding is also suitable for complex shapes, providing freedom to design parts with different graphene and / or carbon black densities and / or wall thicknesses for performance optimization.

[0014] Additional benefits can be gained from the EMI and / or ESD shielding and / or ESD protection of graphene and / or carbon black, as well as other functionalities such as heat resistance, UV resistance, abrasion resistance, wear resistance, and flame retardancy. In some variations, graphene and / or carbon black are included only in the housing coating, thereby reducing the cost of using conductive fillers in the housing.

[0015] With reference to Figures 1 and 2, Figure 1 is a perspective view of a vehicle "V" with an ECU 10, and Figure 2 is an exploded view of the ECU 10. Although Figures 1 and 2 show only one ECU 10, it is possible and common for more than one ECU to be present in a vehicle. Non-limiting examples of ECUs that control or help control various components of a vehicle include ECUs for engine control, automatic speed control, overhead console control, and electronically adjustable steering wheel control, among others. It is also understood that control of one or more vehicle components may be assigned to and performed by a single ECU. For example, an engine control unit ECU (also known as an engine control module (ECM)) may include inputs from, among others, a camshaft position sensor, an air flow sensor, a heated oxygen sensor, a manifold absolute pressure (MAP) sensor, an exhaust gas recirculation (EGR) sensor, a coolant temperature sensor, a throttle position sensor, a crankshaft position sensor, a vehicle speed sensor, and a knock sensor.

[0016] 2, the ECU 10 includes a housing 100, an electronic circuit board 150 (e.g., a printed circuit board (PCB)), and a base 170, which are described in more detail below. The electronic circuit board 150 includes several of the electronic components, such as a core 152 (i.e., a microcontroller) and a memory 154, among others, configured to receive sensor signal inputs and provide device signal outputs such that a desired functionality of one or more vehicle devices is provided. The base 170 provides a platform or support structure upon which the electronic circuit board 150 is mounted. The base 170 can also be attached to another structure, for example, by using threaded fasteners (not shown) extending through openings 172 in the base 170 such that the ECU 10 is securely attached to the vehicle V. Also, although the housing 100 is shown in FIGS. 1 and 2 as a vehicle component housing, the housing 100 can also be an electronics housing for the ECU 10 that is not mounted on a vehicle.

[0017] Referring to Figures 3 and 3A, Figure 3 is a cross-sectional view of the housing 100 and Figure 3A is an enlarged view of portion 3A of Figure 3. In some variations, the housing 100 is formed from or includes one or more planar portions 110 and flanges 120. The housing also includes a polymer core 112 and an overmolded outer layer 114. As used herein, the term "overmolded" refers to an injection molded layer formed on or "above" a previously formed layer, substrate, or core (which may or may not be injection molded), and the term "outer" refers to a surface or layer opposite an electronic wiring board of an ECU that is at least partially contained or disposed within or between the housing 100 and the base 170. The polymer core 112 is formed from a first polymer material and the overmolded outer layer 114 is formed from a second polymer material. The first polymeric material and the second polymeric material may be the same or different polymeric materials. In some variations, the first and / or second polymeric material is at least one of a thermoplastic, a thermosetting epoxy, and a phenolic polymer. For example, in some variations, the first and / or second polymeric material is at least one of polypropylene (PP), polybutylene terephthalate (PBT), acrylonitrile butadiene styrene (ABS), and combinations thereof, among others. Also, in at least one variation of the present disclosure, the first and / or second polymeric material is polypropylene.

[0018] In some variations, the polymer core 112 is formed from a first polymeric material to which is added a reinforcing material that provides structural reinforcement to the housing 100. Non-limiting examples of reinforcing materials include glass (e.g., fiberglass and / or glass beads), talc, one or more inorganic fillers (e.g., calcium carbonate, silica, wollastonite, clay, calcium sulfate fiber, mica, and alumina trihydrate), and combinations thereof.

[0019] In at least one variation, the overmolded outer layer 114 is formed from a second polymeric material having added graphene and / or carbon black. Also, in some variations, the overmolded outer layer 114 is formed from a second polymeric material having between about 2% and about 30% graphene by weight. In such variations, the overmolded outer layer 114 defines a housing skin that provides EMI shielding and / or ESD protection for the electronic wiring board 150. That is, the polymer core 112 and the overmolded outer layer 114 define an EMI shield and / or ESD protective cover.

[0020] The polymer core 112 has a first thickness "t1" and the overmolded outer layer 114 has a second thickness "t2". In some variations, the polymer core 112 has a first thickness t1 between about 1 millimeter (mm) and about 10 mm, and in at least one variation, the first thickness t1 is between about 2 mm and about 5 mm. Also, in some variations, the overmolded outer layer 114 has a second thickness t2 between about 0.5 mm and about 5 mm, and in at least one variation, the second thickness t2 is between about 1 mm and about 2.5 mm.

[0021] As discussed above, in some variations, the polymer core 112 and the overmolded outer layer 114, i.e., the housing 100, define an EMI shield that reflects and / or absorbs EM radiation. In such variations, the housing 100 has a shielding efficiency of at least 30 decibels (dB) for EM radiation frequencies between about 1 kHz and about 100 GHz. For example, in at least one variation, the housing 100 has a shielding efficiency of at least 35 dB for EM radiation frequencies between about 1 kHz and about 100 GHz, and in some variations, the housing 100 has a shielding efficiency of between about 40 dB and about 60 dB for EM radiation frequencies between about 1 kHz and about 100 GHz. The shielding efficiency represents the level of attenuation that the housing 100 provides, and the attenuation (in dB) represents the ratio of EM field strengths measured with and without the housing 100 present, both in coaxial transmission line testing and / or shielded box testing.

[0022] Also, as mentioned above, in some variations, the polymer core 112 and overmolded outer layer 114, i.e., the housing 100, define an ESD protective cover that discharges static electricity. In such variations, the housing 100 may be approximately 10 -10 Antistatic conductivity greater than S / m and approximately 10 -8 For example, in at least one variation, the housing 100 has a .mu.m / cm2 electrostatic discharge conductivity of approximately 10. -9 S / m and approximately 10 -6 Antistatic conductivity of less than 10 S / m and approx. -7 S / m and approximately 10 -3 It has both or either an electrostatic discharge conductivity of less than S / m.

[0023] In some variations, the housing 100 defines an EMI shield with an overmolded layer 114 formed from a second polymeric material having between about 12.5% ​​and about 30% graphene by weight (e.g., between about 15% and about 30% graphene by weight). In at least one variation, the housing 100 defines an ESD protective cover configured for electrostatic discharge with an overmolded layer 114 formed from a second polymeric material having between about 5% and about 17.5% graphene by weight (e.g., between about 5% and about 15% graphene by weight). Also, in some variations, the housing 100 defines an ESD protective cover configured for static electricity conduction with an overmolded layer 114 formed from a second polymeric material having between about 2% and about 12.5% ​​graphene by weight (e.g., between about 2% and about 10% graphene by weight).

[0024] 4A-4C, which illustrate the formation of a housing 100 using an overmolding process according to one aspect of the present disclosure. In particular, and with reference to FIG. 4A, a polymer core 112 is formed by injecting a first polymer material 112p having a reinforcing material (i.e., a mechanical mixture of the first polymer material and the reinforcing material) into a mold cavity 205 defined between a first mold die 200 and a second mold die 210 of a first mold set 20. The polymer core 112 is removed from the mold cavity 205 and placed in another mold cavity 215 defined between another first mold die 220 and another second mold die 230 of the second mold set 22, as shown in Fig. 4B, and a second polymer material 114p having graphene and / or carbon black (i.e., a mechanical mixture of the second polymer material with graphene and carbon black or graphene or carbon black) is injection molded into the mold cavity 215 to form the overmolded outer layer 114, as shown in Fig. 4C. In some variations, the first mold die 220 is the same mold die as the first mold die 200, while in other variations, the first mold die 220 is a different mold die than the first mold die 200.

[0025] Referring to FIG. 5, a two-shot injection molding process or two-shot injection molding machine 30 according to another aspect of the present disclosure is shown forming a housing 100. The two-shot injection molding machine 30 includes a rotatable first mold 300, a second mold 302 having a first mold cavity 310 and a second mold cavity 320, a first injection unit 312, and a second injection unit 314. The first injection unit 312 injects a first polymer material 112p having a reinforcing material into the first mold cavity 310 to form a polymer core 112. The rotatable first mold 300 having the polymer core 112 is then rotated about a mold axis "D" such that the polymer core 112 is disposed in the second mold cavity 320. The second injection unit 314 injects the second polymer material 114p with graphene into the second mold cavity to form the overmolded outer layer 114 on the polymer core 112, and the first injection unit 312 injects the first polymer material 112p with the reinforcing material into the first mold cavity 310 to form another polymer core 112. After the two-shot injection molded outer layer 114 is formed, i.e., after the housing 100 is formed, the rotatable first mold die 300 and the second mold die 302 are separated from each other (in the z-direction), the housing 100 is pushed out (removed) from the rotatable first mold die 300, and the rotatable first mold die 300 rotates about the mold axis D such that the another polymer core 112 is placed in the second mold cavity 320. This cycle, i.e., formation of a polymer core 112 in a first mold cavity 310, formation of an overmolded outer layer 114 on the polymer core 112 in a second mold cavity, removal of the housing from the rotatable first mold 300, and rotation of the rotatable first mold 300, continues to form multiple housings 100.

[0026] 6, which is a flow chart of a method 40 of forming the housing 100. The method 40 includes, at 410, injection molding a first polymeric material 112p having a reinforcing material to form a polymeric core 112, and, at 420, injection molding a second polymeric material 114p having graphene to form an overmolded outer layer 114 on the polymeric core 112. The first polymeric material 112p having a reinforcing material can be a mixture of thermoplastic pellets and a thermoplastic with reinforcing material pellets fed into a first hopper and barrel of a first injection unit such that the first polymeric material 112p having a reinforcing material has a desired reinforcing material content before forming the polymeric core 112 by injection molding. The graphene bearing second polymeric material 114p can also be a mixture of thermoplastic pellets and thermoplastic with graphene pellets fed into a second hopper and barrel of a second injection unit such that the graphene bearing second polymeric material 114p has a desired graphene content prior to injection molding to form the outer overmolded layer 114.

[0027] 3, 4A-4C, and 5 only show the formation of the housing 100 by injection molding a polymer core and an outer overmolded layer onto the polymer core, in some variations the base 170 is similarly formed, that is, in some variations the base 170 defines an EMI shield with a polymer core formed from a first polymer material having a reinforcing material and an outer overmolded layer formed from a second polymer material having graphene.

[0028] In light of the teachings of the present disclosure, the housing 100 with the polymer core 112 and overmolded outer layer 114 (i.e., housing coating) provides EMI shielding without one or more of the limitations of conventional EMI shielding. For example, injection molding of a first polymer material 112p with a reinforcing material and a second polymer material 114p with graphene allows for EMI shielding and / or ESD protective covering that is lighter and more design flexible than metal housings and has fewer EHS and waste disposal limitations than polymer housings with electroless metal, electrolytic plated metal, and / or metallization coatings. Additionally, the housing 100 does not have the coating adhesion limitations of polymer housings with conductive spray coatings because the graphene is disposed within the second polymer material that makes up the overmolded outer layer 114 and is not present as a coating on the polymer core 112.

[0029] The above description is merely exemplary in nature and is not intended to limit the disclosure, its application, or uses in any way. As used herein, the phrase "at least one of A, B, and C" should be interpreted as meaning the logic (A or B or C) by using the non-exclusive logic "or". Various steps in a method may be performed in different orders without altering the principles of the disclosure. The disclosure of ranges includes the disclosure of all ranges and subranges contained within the entire range.

[0030] The headings (such as "Background" and "Summary") and subheadings used herein are intended to provide general organization of topics within the disclosure only and are not intended to limit the disclosure of the technology or any aspect thereof. The description of multiple embodiments having stated features is not intended to exclude other embodiments having additional features or other embodiments incorporating different combinations of the stated features.

[0031] As used herein, the term "about" when associated with a numerical value herein refers to the variation or tolerance of a known commercial and experimental measurement or commercial or experimental measurement with respect to a reference amount. In some variations, such known commercial and experimental measurements or the tolerance of a commercial or experimental measurement is ±10% of the measured value, in other variations, such known commercial and experimental measurements or the tolerance of a commercial or experimental measurement is ±5% of the measured value, and in still other variations, such known commercial and experimental measurements or the tolerance of a commercial or experimental measurement is ±2.5% of the measured value. Also, in at least one variation, such known commercial and experimental measurements or the tolerance of a commercial or experimental measurement is ±1% of the measured value.

[0032] As used herein, the terms "comprise," "include," and variations thereof are intended to be open-ended, such that a recitation of a sequence or list of items does not exclude other similar items that may also be useful in the devices and methods of the present technology. Similarly, the terms "can" and "may," and variations thereof, are intended to be open-ended, such that a recitation that an embodiment may or may include a particular element or feature does not exclude other embodiments of the present technology that do not include that element or feature.

[0033] The broad teachings of the present disclosure can be implemented in a variety of forms. Thus, while the present disclosure includes examples, the true scope of the present disclosure is not intended to be limited thereto, as other modifications will become apparent to those skilled in the art upon review of the present specification and the following claims. References herein to an aspect or aspects mean that a particular feature, structure, or characteristic described with respect to an embodiment or system is included in at least one embodiment or aspect. The appearance of the phrase "in one aspect" (or variations thereof) does not necessarily refer to the same aspect or embodiment. It is also to be understood that the various method steps discussed herein need not be performed in the same order as illustrated, and that not every method step is required in every aspect or embodiment.

[0034] The above description of the embodiments is for illustrative and explanatory purposes, and is not intended to be exhaustive or limiting of the present disclosure. Individual elements or features of an embodiment are generally not limited to the particular embodiment, and can be substituted as necessary and can be used in a selected embodiment without being specifically shown or described. Various modifications of these are also possible. Such variations should not be considered as deviations from the present disclosure, and all such improvements are intended to be within the scope of the present disclosure.

Claims

1. An electronic component housing for an ECU, comprising: The ECU is an electronic wiring board having electronic components; a base configured to mount the electronic wiring board; the electronics housing being formed from one or more flats and a flange; The electronic component housing includes: an injection molded polymer core layer comprising a first polymer material; an injection molded outer overmolded layer including a second polymeric material having graphene; Equipped with The electronic component housing, wherein the overmolded outer layer is disposed on the polymeric core layer and defines a housing skin that provides EMI shielding and / or ESD protection for the electronic wiring board.

2. The electronics housing of claim 1 , wherein the polymer core layer is graphene-free.

3. 10. The electronics housing of claim 1, wherein the polymer core layer includes a reinforcing material that provides structural reinforcement to the electronics housing and is at least one of carbon fiber, glass, talc, inorganic fillers, and combinations thereof.

4. The electronics housing of claim 1 , wherein the first and second polymeric materials are at least one of a thermoplastic, a thermoset epoxy, and a phenolic polymer.

5. 10. The electronics housing of claim 1, wherein the first polymeric material and the second polymeric material are at least one of polypropylene, polybutylene terephthalate, acrylonitrile butadiene styrene, and combinations thereof.

6. The electronics housing of claim 1 , wherein the first polymeric material and the second polymeric material are the same polymeric material.

7. The electronics housing of claim 1 , wherein the first polymeric material and the second polymeric material are polypropylene.

8. 10. The electronics housing of claim 1, wherein the outer overmold layer comprises the second polymeric material having between approximately 2% and approximately 30% graphene by weight.

9. The electronics housing of claim 1 , wherein the polymer core layer and the overmolded outer layer define an EMI shield with a shielding effectiveness of at least 30 dB for EM radiation frequencies from approximately 1 GHz to approximately 40 GHz.

10. 10. The electronics housing of claim 9, wherein the shielding effectiveness is at least 35 dB for EM radiation frequencies from approximately 1 GHz to approximately 40 GHz.

11. 10. The electronics housing of claim 9, wherein the shielding efficiency is from about 35 dB to about 90 dB for EM radiation frequencies from about 1 GHz to about 100 GHz.

12. The electronics housing of claim 1 , wherein the polymer core layer has a thickness of from about 1 mm to about 10 mm.

13. The electronics housing of claim 1 , wherein the outer overmolded layer has a thickness of from about 0.5 mm to about 5 mm.

14. An electronic component housing for an ECU, comprising: The ECU is an electronic wiring board having electronic components; a base configured to mount the electronic wiring board; the electronics housing being formed from one or more flats and a flange; The electronic component housing includes: an injection molded polymer core layer that provides structural reinforcement to the electronics housing and includes a first polymer material having a reinforcing material that is at least one of carbon fiber, glass, talc, inorganic fillers, and combinations thereof; an injection molded outer overmolded layer comprising a second polymeric material having between about 2% and about 30% by weight of graphene, the outer overmolded layer being disposed on the polymeric core layer and defining a housing skin that provides EMI shielding and / or ESD protection for the electronic wiring board; An electronic component housing comprising:

15. The electronics housing of claim 14 , wherein the first and second polymeric materials are at least one of a thermoplastic, a thermoset epoxy, and a phenolic polymer.

16. the polymer core layer having a thickness of about 1 mm to about 10 mm; the housing coating has a thickness of about 0.5 mm to about 5 mm; 16. The electronics housing of claim 15, wherein the polymer core layer with the housing skin has a shielding efficiency of about 35 dB to about 90 dB for EM radiation frequencies from about 1 GHz to about 100 GHz.

17. A method for producing an electronic component housing as claimed in claim 14, the method comprising the steps of: injection molding a first polymeric material having a reinforcing material comprising at least one of carbon fiber, glass, talc, inorganic fillers, and combinations thereof to form a polymeric core layer using a two-shot injection molding machine, the reinforcing material providing structural reinforcement to the electronic component housing; injection molding a second polymeric material having between about 2% and about 30% by weight of graphene to form an overmolded outer layer defining a housing skin on the polymeric core layer using the two-shot injection molding machine; Including, the polymer core layer having a thickness of about 1 mm to about 10 mm; the housing coating has a thickness of about 0.5 mm to about 5 mm; The method, wherein the polymer core layer with the housing skin has a shielding efficiency of about 35 dB to about 90 dB for EM radiation frequencies from about 1 GHz to about 100 GHz.

18. 20. The method of claim 17, wherein the first polymeric material and the second polymeric material are at least one of polypropylene, polybutylene terephthalate, and acrylonitrile butadiene styrene, and combinations thereof.

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