What Materials Should Be Used for High-Temperature-Resistant Labels?

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I. Temperature Classification and Application Scenarios for High-Temperature Labels

Before selecting materials, it is essential to clearly define the temperature conditions of the application. In the industry, high-temperature-resistant labels are generally classified into three categories based on their temperature tolerance, with each level corresponding to specific use scenarios and providing a basis for material selection:

Short-term high-temperature resistance (100–200°C):
Exposure lasts from several hours to a few days. Typical scenarios include food baking identification, temporary high-temperature testing labels for electronic components, and short-term maintenance labels for high-temperature equipment. These applications have relatively low requirements for long-term thermal stability and emphasize cost control and short-term information retention.

Mid-term high-temperature resistance (200–500°C):
Exposure lasts from several days to several months. Typical applications include labeling during electronic component soldering processes, labels for automotive engine compartment parts, and identification for industrial equipment operating at elevated temperatures. Materials must offer both heat resistance and chemical corrosion resistance.

II. Mainstream High-Temperature Label Materials: Properties and Application Matching
1. Polyimide (PI): The Preferred Choice for Low- to Mid-Temperature Applications

Polyimide (PI) is currently the most widely used material for mid-range high-temperature labels. It has a long-term temperature resistance range of –40°C to 260°C and can withstand short-term exposure to temperatures up to 300°C (for 1–2 hours). Its key advantages include excellent flexibility and weather resistance, along with strong chemical resistance and electrical insulation properties. PI materials can withstand industrial oils and mild acids/alkalis, and they offer high print clarity, allowing precise display of text, barcodes, QR codes, and other high-resolution information.

PI labels are mainly suited for low- to mid-temperature industrial and electronic applications, such as labeling during PCB and electronic component soldering processes, labels for parts inside automotive engine compartments, and parameter labels in short-term high-temperature zones of industrial equipment.
Recommended printing methods include UV printing or thermal transfer printing, used in combination with high-temperature-resistant inks rated for ≥260°C to prevent fading or peeling under heat.

Notes:

Prolonged exposure above 260°C may cause aging and yellowing, making PI unsuitable for extreme temperatures above 500°C.

Surfaces should be thoroughly cleaned before application to improve adhesion and prevent edge lifting or detachment under high temperatures.

III. Core Principles for Selecting High-Temperature Label Materials
1. Accurate Temperature Matching with Safety Margins

Material selection should be based on the maximum temperature of the application, with a safety margin of 10–20% to prevent accelerated aging at critical temperatures.
For example:

If the maximum long-term temperature is 200°C, choose PI labels rated for at least 240°C.

If the maximum long-term temperature is 500°C, select ceramic or stainless-steel labels rated for at least 600°C.

It is also important to distinguish between short-term and long-term exposure: short-term applications may use lower-rated materials to control costs, while long-term exposure requires materials with higher thermal stability.

2. Adaptation to Environmental Media and Corrosive Factors

If the environment includes oil, chemicals, or salt spray, materials with strong corrosion resistance should be prioritized:

Oily industrial environments: PI or stainless-steel labels

Acidic or alkaline environments: Ceramic or glass labels

Coastal, high-salt, high-temperature environments: 316 stainless-steel labels

For outdoor high-temperature applications, UV resistance should also be considered. PI labels with UV-resistant coatings or stainless-steel labels can help prevent aging and fading caused by sunlight.

3. Compatibility with Substrates and Installation Requirements

Metal substrates: Suitable for most high-temperature labels; metal or ceramic labels are preferred, installed using screws or high-temperature inorganic adhesives.

Ceramic or glass substrates: Best paired with ceramic or glass labels using high-temperature glass adhesive.

Curved or irregular surfaces: High-temperature paint labels or flexible PI labels ensure close adhesion.

Vibration-prone or deformable substrates: Flexible PI labels are recommended to avoid cracking or detachment associated with rigid materials.

IV. Manufacturing and Usage Considerations

Manufacturing processes must match material properties:

PI labels: UV printing or thermal transfer

Ceramic and metal labels: Laser engraving or chemical etching

Glass labels: High-temperature fired ink printing

High-temperature paint labels: Spray coating followed by high-temperature curing

Avoid standard inks and processes that may fail under high temperatures. Label thickness should be controlled within 0.1–0.5 mm; excessive thickness may lead to deformation or cracking under heat.

Installation guidelines:

Thoroughly clean substrates before installation, removing oil, dust, and rust, and ensure surfaces are dry and flat.

Use high-temperature adhesives (inorganic adhesives or silicone-based high-temperature adhesives) instead of standard double-sided tape.

For screw-mounted metal labels, use high-temperature-resistant screws to prevent rusting.

After installation, allow a curing period of 24–72 hours before use to ensure full adhesion.

Maintenance:

Clean label surfaces regularly with a damp cloth or neutral detergent; avoid organic solvents such as alcohol or acetone.

Do not scrape label surfaces with sharp objects to prevent information wear.

In outdoor or high-temperature/high-humidity environments, apply specialized protective coatings periodically to enhance weather resistance.

If labels crack, detach, or become illegible, replace them promptly to avoid compromising equipment operation or safety warnings.