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Polyimide PCB: Types, Applications, and Benefits

Most manufacturers produce their printed circuit boards with FR4 materials. After all, these boards are cheap and useful for various applications. But, apart from the FR4, other printed circuit board materials may be ideal for specific applications. Hence, an excellent example of another board material is polyimide. Indeed, the polyimide PCB properties may suit your projects—based on different factors.

But, how do you know if the polyimide or polyamide PCBs are perfect for you?

So, in this article, you’ll learn about the features of these boards, how they affect your work, and more.

Let’s begin!

What is Polyimide PCB?

Polyimide circuit board

Polyimide circuit board

Polyamide or polyimides are polymers that comprise imide monomers. This category of polymers contains different materials (synthetic and natural). That said, examples of natural polyamides are wool, silk, etc.

But, when it comes to producing PCBs, manufacturers use synthetically mass-produced polyamide for board bases.

How do you produce synthetic polyimides? In truth, you can do this by polymerizing different elements with imide structures. Plus, the process involves using maleic anhydride and bismaleimides.

Also, the type of additives and chemicals you use in polymerizing determines the kind of polyimide you’ll create.

Polyimide PCB Types

So, here are the different polyimide PCB types:

2nd Generation Polyimide or Pure Polyimide

Pure Polyimide

Source: Pixels

This PCB doesn’t have extra features like brominated flame retardants—which is a good thing. Again, that’s because lack of flame retardants translates to extreme stability and flexibility. So, you can use the pure polyimide or polyimide flex PCB for communicating and electrical devices.

No doubt, this polyimide PCB type is one of the oldest, but it has widespread use due to its thermal stability and extreme endurance against temperature.

3rd Generation Polyimide

printed circuit board

printed circuit board

In truth, the 3rd generation polyimide is an upgraded version of pure polyimides. Plus, it features extra additives that make them flame resistant. Also, this polyimide’s flammability resistance helps stop an accidental electric fire.

But this feature comes at a price because the 3rd generation polyimide isn’t thermally stable like the pure polyamides. Further, this polyimide is pretty easy to produce. Consequently, you can build this PCB in bulk, faster than another polyimide flexible PCB.

Filled Polyimide

You can classify the filler polyimide as multilayer PCBs. How? Because it consists of different filler materials, which helps prevent resin shrinkage. Also, the filled polyimide system comprises a filler and polyimide.

Further, resin shrinkage affects a board’s longevity. It makes circuit boards vulnerable to cracks and frail during the curing or drilling process. So, additional fillers help to boost a circuit board’s durability and strength.

Low-Flow Polyimides

The low-flow polyimides are the opposite of pure polyimides in terms of flexibility. You can also call them the rigid PCB. Plus, this feature is beneficial—especially if your application requires a rigid PCB that withstands adverse conditions.

Characteristics of the Polyimide PCB

You can get the best out of a polyimide PCB. But it’s crucial to understand the features first. Here they are:

Resistant to Chemicals

Polyimide PCB has chemical stability. In other words, you won’t get adverse effects when you expose the polyimide to different corrosive chemicals.

Thermal Stability

When there’s a wide range of temperatures, polyimides have extreme stability. And the PCB also supports standard hostile inhospitable temperatures (close to 260 degrees Celsius).

Also, polyimide PCBs have excellent thermal conductivity, resisting thermal damage during production or repair processes.

Remarkable Flexibility

Polyimide material has exceptional flexibility. Hence, you can use the material for manufacturing flexible and rigid-flex PCBs.

High Durability

Aside from the polyimide PCB’s resistance to chemicals and heat, they are resistant to physical stress. That is, the PCBs maintain their shape irrespective of the thermal and physical factors that affect them. Hence, they are perfect for field repairs and harsh environments applications.

Outstanding Tensile Strength

Tensile strength is when a material can support a maximum load without cracking when you stretch it, divided by the material’s original cross-sectional area.

So, even though the polyimide PCB is quite flexible, the material is solid and resilient to warping (twisted out of shape). Hence, polyimide PCBs are ideal for applications that need physical durability.

Applications

The most common applications of polyimide PCB include:

Automotive Electronics

Indeed, electric components in automotive industries usually face a lot of challenging conditions. Plus, they need to function regardless of extreme weather conditions (summer and cold) with continuous pushing of multiple components.

Car Fuse box with polyimide PCB

Car Fuse box with polyimide PCB

That said, automotive components naturally need a durable PCB, and the polyimide is up to the task.

Medical Industry

Before performing certain operations in the medical industry like prosthetics, advanced imaging, implants, etc., you need a high-efficiency application. In truth, you can get this high-performing efficiency with polyimide PCBs.  

Prosthetic limbs using Polyimide PCB

Prosthetic limbs using Polyimide PCB                                                                                                                                                                                           

Computer and Laptops

Indeed, flexibility and durability are the two significant factors that computers and laptops need to resist the physical stress of daily use. Also, the computer PCBs may become hot while operating.

Polyimide PCB in Laptop

Polyimide PCB in Laptop

Hence, you need to use a polyimide and rigid-flex PCB in the PCBs’ environment due to their thermal stability, flexibility, and durability.

Polyimide VS FR4 Materials

Here is a table that compares polyimide materials vs. FR4 materials

Here is a table that compares polyimide materials vs. FR4 materials
Here is a table that compares polyimide materials vs. FR4 materials

Final Words

Polyimide PCBs are suitable for a wide variety of applications. In truth, it’s all thanks to its properties. Also, the FR4 material poses a good option as well. But you need to determine the best option that fits your board applications perfectly.

So, do you need help knowing if polyimide boards are ideal for your projects? Or do you want to get the best PCBs? Please feel free to reach us.

Hommer Zhao
Hi, I am Hommer, the founder of WellPCB. So far, we have more than 4,000 customers worldwide. If you have any questions, you can feel free to contact me. I really appreciate any help you can provide.

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