Polyimide Labels for Electronics Manufacturing: Why They’re Used for PCB Identification

Electronics manufacturing environments place demanding requirements on product identification labels. Circuit boards often need permanent labels containing serial numbers, barcodes or QR codes that remain readable throughout manufacturing and for the lifetime of the product.

Many standard label materials cannot survive the high temperatures, chemical exposure and handling involved in PCB production. For this reason, electronics manufacturers frequently use polyimide labels, which are specifically designed for high-temperature applications.

Polyimide labels are widely used for PCB identification because they offer excellent heat resistance, dimensional stability and long-term durability.

In this guide

• What polyimide labels are
• Why they are used in electronics manufacturing
• Temperature resistance and soldering processes
• Adhesives for polyimide labels
• Polyimide vs polyester labels
• Printing barcodes and QR codes on polyimide labels
• Static dissipative options
• Common applications for polyimide labels
• Choosing the right polyimide label

What Are Polyimide Labels?

Polyimide labels are manufactured from a high-performance polymer film designed to withstand extreme temperatures and harsh industrial environments. The material is widely known for its thermal stability and is often associated with the name Kapton, which is commonly used in electronics manufacturing discussions.

Unlike many conventional label materials, polyimide does not easily shrink, distort or degrade when exposed to high temperatures. This makes it particularly suitable for printed circuit boards that will pass through soldering processes during production.

Polyimide labels are commonly used for:

• PCB identification labels
• high-temperature manufacturing processes
• electronics traceability labels
• durable barcode labels
• component and assembly identification

Because of these properties, polyimide labels are widely considered one of the standard materials for PCB labelling in demanding manufacturing environments.

Why They Are Used in Electronics Manufacturing

Electronics manufacturing presents a combination of challenges that many standard labels cannot tolerate. During production, labels may be exposed to:

• temperatures above 200°C during soldering
• flux residues and cleaning solvents
• mechanical handling during assembly
• tight space constraints on modern circuit boards
• long-term traceability requirements

Paper labels and many general-purpose plastics are not designed for this environment. They may shrink, curl, discolour or detach, especially when exposed to repeated heating cycles.

Polyimide labels are chosen because they retain their shape and remain stable under these conditions. In applications where the label must stay attached and readable throughout manufacturing, this stability is essential.

Our guide to why PCB labels fail in electronics manufacturing explains some of the most common failure modes that occur when unsuitable materials are used.

Temperature Resistance and Soldering Processes

One of the main reasons electronics manufacturers use polyimide labels is their ability to tolerate high temperatures during soldering processes.

Processes such as reflow soldering and wave soldering can expose circuit boards to temperatures well above the limits of many standard label materials. In these conditions, low-performance labels may shrink, become brittle or lose adhesive strength.

Polyimide films are specifically engineered for high-temperature environments and are widely used where boards pass through soldering stages before final assembly. Their dimensional stability is especially important on small PCB labels, where even slight material distortion can affect barcode readability.

For applications that involve direct exposure to soldering heat, you may also find our guide to labels that survive the soldering process useful.

Where manufacturing conditions are particularly demanding, engineers should also consider the number of heating cycles involved, not just the peak temperature. A label that survives one pass through a heated process may still fail if it is repeatedly exposed to elevated temperatures during multiple production stages.

Adhesives for Polyimide Labels

The face material is only part of the solution. In high-temperature PCB applications, the adhesive is equally important.

If an adhesive softens, degrades or loses bond strength during soldering or cleaning, the label may lift at the edges or detach completely. That means even a high-performance face material such as polyimide can fail if the adhesive is not suitable for the process.

For this reason, PCB labels normally require adhesives designed for:

• high-temperature exposure
• strong adhesion to circuit board surfaces
• resistance to cleaning solvents and chemicals
• long-term stability after manufacture

Adhesive selection should always be considered alongside the label material itself. In many cases, a label failure attributed to the face material is actually caused by the wrong adhesive specification.

Polyimide vs Polyester Labels

Polyimide labels are not the only durable synthetic labels available. Polyester is also widely used in industrial labelling and can be an excellent choice in many applications.

The difference is that polyester is generally used for durable identification in environments that do not involve extreme heat, whereas polyimide is selected specifically for applications where high temperature resistance is essential.

As a general rule:

• Polyimide labels are preferred for PCB manufacturing, soldering processes and high-temperature applications
• Polyester labels are often used for asset labels, rating plates and durable general industrial identification

Both materials can offer excellent durability, but where soldering or repeated thermal exposure is involved, polyimide is usually the safer choice.

We explore this comparison further in our guide to polyester vs polyimide labels for electronics manufacturing.

Printing Barcodes and QR Codes on Polyimide Labels

Polyimide labels are often used for traceability, which means they frequently carry serial numbers, barcodes, QR codes or data matrix codes.

To ensure these codes remain readable, the printing method matters. For demanding environments, thermal transfer printing with resin ribbons is typically recommended because it produces durable print that resists heat, chemicals and abrasion.

This is especially important where labels are very small. Modern PCBs often allow only a tiny area for identification, yet the code still needs to scan reliably during production and service.

When designing small polyimide barcode labels, key considerations include:

• printer resolution
• barcode size
• quiet zones around the code
• scanner capability
• material stability during heating

If you are working with compact traceability labels, our guides to how small a QR code label can be and barcode readability problems in small labels explain these issues in more detail.

Static Dissipative Options

Some electronics manufacturing environments also require label materials that help minimise the risk of electrostatic discharge.

In ESD-sensitive environments, static build-up can damage components or interfere with handling procedures. In these cases, manufacturers may specify static dissipative label constructions designed to reduce the risk of charge accumulation.

Polyimide labels can sometimes be supplied in constructions suited to these requirements, depending on the application and performance needed.

If ESD control is an important part of your process, see our guide to ESD safe labels for electronics manufacturing.

Common Applications for Polyimide Labels

Although polyimide labels are strongly associated with PCB identification, they are also used in other demanding manufacturing applications where high temperatures or harsh processing conditions are involved.

Typical uses include:

• printed circuit board serial number labels
• assembly and process tracking labels
• high-temperature component identification
• small barcode and QR code traceability labels
• electronics manufacturing work-in-progress labels

Because the material performs so well in compact, high-stress environments, it is especially valuable where identification must remain permanent and machine-readable.

In practice, many manufacturers choose custom-made polyimide labels so the size, adhesive, print format and barcode layout are all matched to the exact production process.

Choosing the Right Polyimide Label

Selecting the right polyimide label involves more than simply specifying the face material. The full label construction should be matched to the application.

Important factors include:

• maximum temperature exposure
• number of heating cycles
• label size and available PCB space
• barcode or QR code requirements
• surface type and adhesion requirements
• chemical exposure during cleaning
• ESD requirements
• expected lifespan of the label

When these factors are considered properly, polyimide labels can provide reliable long-term performance through both manufacturing and the operational life of the product.

Our guide to how to specify labels for electronics manufacturing provides a broader overview of the specification process.