Last Tuesday the U.S. Patent and Trademark Office officially published a newly granted patent of Apple's that relates to a process of bonding plastic to metal, and more particularly to filling pores or other apertures in the metal with a material that bonds more strongly with the plastic than does the metal alone. While this creates a more durable product than metal alone, it could also provide a higher degree of waterproofing to the product.

At the moment, Apple is placing more emphasis on the use of glass for iPhone construction for wireless charging purposes. So, while the patent illustrates that their hybrid metal and plastic process of construction could apple to an iPhone and MacBook, it's the MacBook where this patent is likely to surface if Apple gives the project the green light.  

In some portable electronic devices, thermoplastic components may be molded directly onto metal surfaces to provide waterproofing as well as decorative and aesthetically pleasing surfaces on the device.

Waterproof thermoplastic surfaces do not rust or corrode and thus are preferred over some metal surfaces which may not be as resistant to these elements.

In addition, in order to protect the metal surface and certain electronic components, a watertight seal may be desirable between the thermoplastic material layer and the metal housing of the device.

In patent figure 3 below, the multi-layered structure of the plastic material #130, the adhesive #310, and metal substrate #120 may have sufficiently strong and structurally dense bonds between contiguous surfaces formed by the plastic, adhesive and metal, to render the structure liquid-tight.

This may be useful if the structure is an electronic device housing, insofar as a liquid-tight bond may protect components within the housing from water damage or the like.

In addition to providing a waterproof or other liquid-proof bond, the strength of the bonds between the materials may provide some degree of impact resistance to the electronic device. The increased bond strength thus results in a sturdier, more durable product.

In 2017 Patently Apple covered two titanium related patent applications into one report to illustrate that there was more to this project than a single invention.  While Apple was granted a patent for one of the two 2017 patents filings last Tuesday, you could check out our previous report here where you'll see Apple envision the use of titanium alloys for a future MacBook without the plastic hybrid approach. In fact, one Apple team envisions the use of a titanium alloy for future iPads and the Apple Watch as well. 

Apple was granted patent 10,688,624 on Tuesday by the US Patent and Trademark Office.  

Apple Inventors

Derek Krass: Plastic Material Team Manager; Lead polymer characterization laboratory team that supports all development work for iPhone, iPad, Apple Watch, MacBooks, Softgoods and Accessories.

Paul Choiniere: Experienced Engineering Manager - Plastics, Tooling, Sourcing

James Krogdahl: Was Senior Materials Engineer at Apple. He's since moved on to Facebook working on their AR/VR Hardware.