Updated on 10.21

PET vs. PI High-Temperature Tape: What’s the Difference—and Why Does PI Cost More?

In electronics and semiconductor manufacturing, engineers often ask:

“How much heat can high-temperature tape withstand—and could choosing the wrong tape affect production yield?”

“High-temperature tape” is not a single material. It is a broad category of products. Depending on the backing material and adhesive system, the five common types cover temperature ratings from around 130°C to 350°C.

Among these, PET and PI high-temperature tapes are two of the most frequently compared options.

Both are supplied as thin-film rolls, often with a translucent or amber appearance, yet their prices can differ severalfold. Understanding the differences is essential for material selection and purchasing.

1. Understanding the Five Main Types of High-Temperature Tape

The heat resistance of a tape depends on both its backing material and its adhesive system.

Even with the same PET backing, switching from an acrylic adhesive to a silicone adhesive can change the temperature rating by around 30°C. Changing the adhesive system on a PI backing can also increase its usable temperature range.

The table below summarizes typical temperature ranges. "Continuous" refers to prolonged use, while "short-term" refers to exposure lasting no more than 30 minutes.

Tape Type	Backing and Adhesive	Continuous Use	Short-Term Exposure	Typical Applications
PET tape with acrylic adhesive	Polyester film + acrylic adhesive	130–150°C	180°C	Electronic component packaging, PCB masking, appliance paint masking
PET tape with silicone adhesive	Polyester film + high-temperature silicone adhesive	150–180°C	220°C	Electronic masking and coating protection requiring higher heat resistance
PI tape with acrylic adhesive	Polyimide film + acrylic adhesive	180–230°C	280°C	PCB soldering and electrical insulation
PI tape with silicone adhesive	Polyimide film + high-temperature silicone adhesive	220–260°C	300°C	Semiconductor processing, IC packaging, reflow soldering masking
PTFE-coated fiberglass tape	Fiberglass cloth + PTFE coating + silicone adhesive	260–300°C	350°C	Heat sealing, mold release, lithium-ion battery electrode processing, high-temperature piping

Considering heat resistance, dielectric performance, convertibility, and chemical resistance together, PI film with a high-temperature silicone adhesive offers one of the strongest overall performance profiles among these options. This helps explain its widespread use in high-temperature semiconductor masking.

The distinction between continuous and short-term ratings matters. Some suppliers advertise only the short-term peak temperature, while production processes may involve much longer exposure.

Choose a tape based on its continuous-use rating and your actual exposure conditions—not just the peak temperature on the label.

2. PET vs. PI: The Key Differences

Comparing silicone-adhesive PET tape with silicone-adhesive PI tape reveals four main differences.

① Backing Material

PET stands for polyethylene terephthalate, commonly called polyester. PI stands for polyimide.

PET is a widely used engineering plastic, while PI is a high-performance specialty polymer. Their different molecular structures give PI a substantially higher heat-resistance ceiling.

② Temperature Resistance

PET with silicone adhesive:

 150–180°C continuous use; up to 220°C short-term.

PI with silicone adhesive:

 220–260°C continuous use; up to 300°C short-term.

The continuous-use ranges are roughly 70–80°C apart, while the short-term ratings differ by about 80°C.

③ Electrical Insulation, Chemical Resistance, and Convertibility

Temperature resistance is only part of the picture.

PI generally offers stronger electrical insulation and dielectric performance, better chemical resistance, and greater dimensional stability at elevated temperatures.

For semiconductor and precision electronics applications, these properties can matter just as much as the maximum temperature rating.

④ Price

PI tape typically costs considerably more than PET tape.

The goal is to select a tape that meets the process requirements at an appropriate cost.

What Happens If You Choose the Wrong Tape?

A tape with an insufficient temperature rating may not fail immediately. Problems can develop gradually during processing.

Adhesive softening and contamination:

 Excessive heat can cause the adhesive to soften or flow, contaminating components and fixtures.

Adhesive residue:

 Residue left after removal can require additional cleaning or rework.

Component damage:

 If masking fails, hot air or molten solder may reach areas that should remain protected.

Reduced production yield:

 Any of these issues can lead to defects and lower yield.

Tape selection should therefore start with the maximum process temperature and the time spent at that temperature.

Typical Applications

PET high-temperature tape:

General electronics manufacturing
PCB masking
Paint and coating masking for appliances and metal parts
Packaging and temporary securing

PI high-temperature tape:

SMT reflow soldering masking
High-temperature protection during IC packaging
Masking in CoWoS processes
CMOS image sensor protection
High-temperature baking and curing masking
Protection of precision semiconductor components

PET is often sufficient for general electronics processes. For reflow soldering, semiconductor processing, and prolonged exposure to higher temperatures, PI is generally the more suitable choice.

3. Where Is the Global Market Heading?

Demand for high-temperature tapes is being driven by two major trends: automotive lightweighting and electric vehicle batteries.

In 2025, the global adhesive tape market was valued at approximately US$72 billion, with a compound annual growth rate of around 6.2%. Asia-Pacific accounted for more than 48% of global consumption.

Battery insulation and securing applications helped drive a 14.3% year-on-year increase in shipments of PI and heat-resistant PET tapes.

More specifically, the combined global market for cell termination tapes, electrode protection tapes, and thermally conductive tapes exceeded US$4.5 billion in 2025. Electric vehicles used approximately six times as much of these tapes as conventional internal combustion engine vehicles.

As electric vehicle sales grow, demand for high-temperature tapes becomes increasingly tied to production requirements.

Global trade patterns are also shifting.

In 2025, worldwide adhesive tape trade volume reached approximately 2.8 million metric tons. China led with a 32% share of exports, but its average export price was 5.2% lower than in 2020, reflecting intensifying price competition in lower- and mid-range products.

Germany and Japan maintained strong positions as net exporters of high-end products. Their average prices were respectively 3.1 times and 2.8 times those of comparable Chinese products.

Meanwhile:

Southeast Asia

 increasingly imported semi-finished materials from China for further processing and re-export.

India

 used tariffs to encourage import substitution.

Mexico

 strengthened its role as an assembly and distribution hub within the North American free-trade region.

4. A Practical Tape Selection Checklist

Before choosing a high-temperature tape, ask four questions:

What is the maximum process temperature, and how long will exposure last?

This helps determine whether PET or PI is the appropriate backing.

Is electrostatic discharge protection required?

Semiconductor and precision electronics applications often require ESD control.

Does the tape need to be die-cut or converted into specific shapes?

This affects the backing and converting requirements.

What surface will the tape adhere to?

Glass, metal, and IC surfaces can place different demands on the adhesive system.

There is no single best high-temperature tape—only the tape that best fits your process.

PET is a practical option for general electronics applications. PI is better suited to reflow soldering, semiconductor processing, and prolonged high-temperature exposure. For more demanding applications with sufficient budget, PTFE-coated fiberglass tape may also be worth considering.

Prepared by the high-temperature tape team at ONEMICRON TAPE. Contact us to discuss material selection for your process.